Incomplete metabolism of phytoestrogens by gut microbiota from children under the age of three.

Science.gov (United States)

Gaya, Pilar; Sánchez-Jiménez, Abel; Peirotén, Ángela; Medina, Margarita; Landete, José Maria

2018-05-01

Phytoestrogens are plant-derived polyphenols with structural and functional similarities to mammalian oestrogens. The aim of this work was to study the metabolism of phytoestrogens by children's intestinal microbiota and to compare it with previous results in adults. Faecal samples of 24 healthy children were subjected to phytoestrogen fermentation assay. Only one child produced equol, while O-desmethylangolensin was found in all. Urolithin production was detected in 14 children and enterolactone in 10. Further comparison with the metabolism of phytoestrogens by adult intestinal microbiota reflected that glycitein, dihydrogenistein, urolithins D and E, enterolactone, secoisolariciresinol and arctigenin were the most important metabolites differentiating between adult and child microbial gut metabolism. Although the child intestinal microbiota showed the ability to metabolise isoflavones, ellagitannins and lignans to a certain extent, it generally showed a reduced metabolism of phytoestrogens, with a lack of 5-hydroxy equol and enterodiol, and less urolithins and enterolactone producers.

Distribution profiles of transient receptor potential melastatin- and vanilloid-related channels in rat spermatogenic cells and sperm.

Science.gov (United States)

Li, Shilin; Wang, Xinghuan; Ye, Haixia; Gao, Weicheng; Pu, Xiaoyong; Yang, Zhonghua

2010-03-01

In the present study, we aimed to investigate the expression and distribution of transient receptor potential melastatin (TRPM)- and vanilloid (TRPV)- related channels in rat spermatogenic cells and spermatozoa. Spermatogenic cells and spermatozoa were obtained from male Sprague-Dawley rats. Reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of all TRPM and TRPV channel members with specific primers. Western blot analysis was applied for detecting the expression of TRPM and TRPV channel proteins. Immunohistochemistry staining for TRPM4, TRPM7 and TRPV5 was also performed in rat testis. The mRNAs of TRPM3, TRPM4, TRPM7 and TRPV5 were detected in the spermatogenic cells and spermatozoa in rat. Western blot analysis verified the expression of TRPM4, TRPM7 and TRPV5 in the rat spermatogenic cells and spermatozoa. Immunocytochemistry staining for TRPM and TRPV channel families indicated that TRPM4 and TRPM7 proteins were highly expressed in different stages of spermatogenic cells and spermatozoa, while TRPV5 protein was lowly expressed in these cells. Our results demonstrate that mRNAs or proteins for TRPM3, TRPM4, TRPM7 and TRPV5 exist in rat spermatogenic cells and spermatozoa. These data presented here may assist in elucidating the possible physiological function of TRPM and TRPV channels in spermatogenic cells and spermatozoa.

Identification and characterization of a phytoestrogen-specific gene from the MCF-7 human breast cancer cell

International Nuclear Information System (INIS)

Ramanathan, Lakshmi; Gray, Wesley G.

2003-01-01

Phytoestrogens are a group of compounds present in human diet that display estrogenic-like properties. Several studies have demonstrated that populations who consume large quantities of phytoestrogens have a reduced risk of estrogen-dependent cancers. Although it has been shown that certain phytoestrogens modulate estrogen action, their biological role in cancer reduction remains unclear. Through the use of differential display reverse transcriptase-polymerase chain reaction and representational difference analysis of cDNA, we have identified several phytoestrogen-responsive genes from the human breast cancer cell MCF-7. Two of these genes, PE-13.1 and pRDA-D, have been characterized in greater detail in this study. These genes were not previously known to be regulated by phytoestrogen or estradiol. PE-13.1 is a novel gene that specifies the coding of a 1.10-kb mRNA transcript. Northern blot analysis confirmed that the PE-13.1 transcript is up-regulated by phytoestrogens (Genistein, sevenfold; Zearalenone, twofold) and is nonresponsive to estradiol. Conversely, the pRDA-D transcript was down-regulated by both phytoestrogens and estradiol. The antiestrogen ICI-182,780 inhibits the expression of PE-13.1 and reverses the inhibition of pRDA-D expression induced by phytoestrogens and estradiol. Analysis of the tissue distribution of PE-13.1 transcript by RNA blot reveals that this transcript is expressed in both normal and tumor tissues. This report demonstrates for the first time the presence of two phytoestrogen-responsive genes that may be used as molecular markers in understanding the role dietary estrogen plays in cancer prevention

Phytoestrogens and Mycoestrogens Induce Signature Structure Dynamics Changes on Estrogen Receptor α

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Xueyan Chen

2016-08-01

Full Text Available Endocrine disrupters include a broad spectrum of chemicals such as industrial chemicals, natural estrogens and androgens, synthetic estrogens and androgens. Phytoestrogens are widely present in diet and food supplements; mycoestrogens are frequently found in grains. As human beings and animals are commonly exposed to phytoestrogens and mycoestrogens in diet and environment, it is important to understand the potential beneficial or hazardous effects of estrogenic compounds. Many bioassays have been established to study the binding of estrogenic compounds with estrogen receptor (ER and provided rich data in the literature. However, limited assays can offer structure information with regard to the ligand/ER complex. Our current study surveys the global structure dynamics changes for ERα ligand binding domain (LBD when phytoestrogens and mycoestrogens bind. The assay is based on the structure dynamics information probed by hydrogen deuterium exchange mass spectrometry and offers a unique viewpoint to elucidate the mechanism how phytoestrogens and mycoestrogens interact with estrogen receptor. The cluster analysis based on the hydrogen deuterium exchange (HDX assay data reveals a unique pattern when phytoestrogens and mycoestrogens bind with ERα LBD compared to that of estradiol and synthetic estrogen modulators. Our study highlights that structure dynamics could play an important role in the structure function relationship when endocrine disrupters interact with estrogen receptors.

Phytoestrogens dietary intake and health status of retiree from middle-notrh Slovakia region

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Jozef Čurlej

2015-12-01

Full Text Available Phytoestrogens found in foods of plant origin presents chemical substances that possess a wide range of biochemical benefits. It has been found that they contribute in different health related problems. A wide range of commonly consumed foods contain appreciable amounts of phytoestrogens. Consumption of diet rich to phytoestrogen acts as a protective factor against many diseases such as cardiovascular diseases, post-menopausal symptoms in the context of osteoporosis, cancerous illnesses of colon, prostate and breast. Three main classes of phytoestrogens covers: isoflavones, lignans and coumestans. Selected nine major phytoestrogens had been analyzed simultaneously in the same foods. Questionnaire designed to determine intake frequency as well as amount of selected foods and the most common diseases presented in the population has been used to find relationships between dietary habits and health status. Evaluation of selected goals in the present study has been realized in cooperation with 140 respondents in retired age (divided into Males - covered by 34 individuals and Females - 106 individuals, comming from middle-north Slovakia region. On the base of collected data it can be concluded, that evaluated population is presented by high values of lignans intake and particularly secoisolariciresinol, mainly caused by relative high proportion of cereals and linseed in the diet. Furthermore, the relationship between phytoestrogens intake and eating habits as well as its contribution in protection against selected diseases was demonstrated. Normal 0 21 false false false CS JA X-NONE

Radiosensitization of mouse spermatogenic stem cells by Ro-07-0582

International Nuclear Information System (INIS)

Suzuki, N.; Withers, R.; Hunter, N.

1977-01-01

The hypoxic character of the spermatogenic stem cells of the mouse testis was investigated by measuring the effect on radiosensitivity of treatment with the hypoxic cell radiosensitizer, Ro-07-0582 or hyperbaric oxygen (30 psi). The D 0 values obtained were 181 (161-207) rad for irradiation alone, 140 (133-148) rad for irradiation after treatment with Ro-07-0582, and about 100 rad for irradiation in the presence of hyperbaric oxygen. Ro-07-0582 alone was slightly cytotoxic. The results demonstrate that mouse spermatogenic stem cells are radiosensitized by Ro-07-0582 or hyperbaric oxygen and are not as well oxygenated as other normal tissues

Endocrine disrupting effects in rats perinatally exposed to a dietary relevant mixture of phytoestrogens

DEFF Research Database (Denmark)

Boberg, Julie; Mandrup, Karen; Jacobsen, Pernille Rosenskjold

2013-01-01

Dietary phytoestrogens may prevent certain human diseases, but endocrine activity has been reported in animal studies. Sprague-Dawley rats were exposed perinatally to a 1-, 10- or 100-fold “high human dietary intake” mixture of 12 phytoestrogens consisting of mainly the lignan secoisolarici resinol...... genes in testis and prostate were unaffected. Decreased serum estradiol was seen in genistein-exposed dams. This study indicated adverse effects at high intake levels in rats, but does not provide evidence for risk of phytoestrogen-mediated endocrine disruption at normal human dietary consumption levels...

Effect of low dose X-ray irradiation on apoptosis in spermatogenic cells of mouse testes

International Nuclear Information System (INIS)

Liu Guangwei; Liu Shuchun; Lu Zhe; Gong Shouliang

2003-01-01

To study the effects of low dose radiation (LDR) with different doses of X-rays on the apoptosis in spermatogenic cells of male Kunming mouse testes. The time-effect and dose-effect of apoptosis in the different stages of spermatogenic cell cycles of mouse testis after LDR with different doses of X-rays were studied with light microscope using the methods of TdT-mediated dUTP nick end labeling (TUNEL) and HE staining. The apoptosis of spermatogenic cells induced by LDR had a remarkable regularity in cell types. When the dose was 0.025 Gy, spermatogonium apoptosis was taken as main. With the dose increase of irradiation (0.025-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic rate of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarcely occurred after irradiation with low dose. The apoptosis of spermatogenic cells induced by LDR has a regular change, which provides a further experimental evidence for the mechanism study of hormesis by LDR

Radiosensitivity of spermatogenous epithelium stem cells of mice of different strains and age

International Nuclear Information System (INIS)

Konoplyannikova, O.A.; Konoplyannikov, A.G.

1988-01-01

In experiments on CBA and BALB/c male mices (3 months of age) and F 1 (CBAxC57BL/6) hybrides (at the age of 3, 12, and 24 months) a difference was noted in the radiosensitivity of spermatogenous epithelium stem cells displayed by the changes in their colony-forming ability to testicular tubules 42 days following local 60 Co-γ-irradiation. The older the hybrid mice the smaller was the number of spermatogenous epithelium stem cells

Phytoestrogens levels determination in the cord blood from Malaysia rural and urban populations

International Nuclear Information System (INIS)

Mustafa, A.M.; Malintan, N.T.; Seelan, S.; Zhan, Z.; Mohamed, Z.; Hassan, J.; Pendek, R.; Hussain, R.; Ito, N.

2007-01-01

This study is a result of an analysis of free and conjugated phytoestrogens daidzein, genistein, daidzin, genistin and coumesterol in human cord blood plasma using LCMS. Cord blood was collected from urban and rural populations of Malaysia (n = 300) to establish a simple preliminary database on the levels of the analyzed compounds in the collected samples. The study also aimed to look at the levels of phytoestrogens in babies during birth as this may have a profound effect on the developmental process. The sample clean up was carried out by solid-phase extraction using C18 column and passed through DEAE sephadex gel before analysis by LCMS. The mean concentrations of total phytoestrogens were daidzein (1.4 ± 2.9 ng/ml), genistein (3.7 ± 2.8 ng/ml), daidzin (3.5 ± 3.1 ng/ml), genistin (19.5 ± 4.2 ng/ml) and coumesterol (3.3 ± 3.3 ng/ml). Distribution of phytoestrogen was found to be higher in samples collected from rural areas compared to that of urban areas

Phytoestrogens alter the reproductive organ development in the mink (Mustela vison)

International Nuclear Information System (INIS)

Ryoekkynen, Ari; Nieminen, Petteri; Mustonen, Anne-Mari; Pyykoenen, Teija; Asikainen, Juha; Haenninen, Sari; Mononen, Jaakko; Kukkonen, Jussi V.K.

2005-01-01

The aim of the present study was to examine the reproductive effects of two perorally applied phytoestrogens, genistein (8 mg/kg/day) and β-sitosterol (50 mg/kg/day), on the mink (Mustela vison) at human dietary exposure levels. Parental generations were exposed over 9 months to these phytoestrogens and their offspring were exposed via gestation and lactation. Parents and their offspring were sampled 21 days after the birth of the kits. Sex hormone levels, sperm quality, organ weights, and development of the kits were examined. The exposed females were heavier than the control females at the 1st postnatal day (PND). The control kits were heavier than the exposed kits from the 1st to the 21st PND. Phytoestrogens did not affect the organ weights of the adult minks, but the relative testicular weight of the exposed kits was higher than in the control kits. The relative prostate weight was higher and the relative uterine weight lower in the β-sitosterol-exposed kits than in the control kits. Moreover, the plasma dihydrotestosterone levels were lower in the genistein-exposed male kits compared to the control male kits. This study could not explain the mechanisms behind these alterations. The results indicate that perinatal phytoestrogen exposures cause alterations in the weight of the reproductive organs of the mink kits

Higher usual dietary intake of phytoestrogens is associated with lower aortic stiffness in postmenopausal women

NARCIS (Netherlands)

Schouw, van der Y.T.; Pijpe, A.; Lebrun, C.E.I.; Bots, M.L.; Peeters, P.H.M.; Staveren, van W.A.; Lamberts, S.W.J.; Grobbee, D.E.

2002-01-01

Objective¿ Phytoestrogens have been postulated to protect against cardiovascular diseases, but few studies have focused on the effect of Western dietary phytoestrogen intake. Methods and Results¿ Four hundred three women with natural menopause either between 1987 and 1989 or between 1969 and 1979

Visual spatial memory is enhanced in female rats (but inhibited in males by dietary soy phytoestrogens

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Setchell Kenneth DR

2001-12-01

Full Text Available Abstract Background In learning and memory tasks, requiring visual spatial memory (VSM, males exhibit superior performance to females (a difference attributed to the hormonal influence of estrogen. This study examined the influence of phytoestrogens (estrogen-like plant compounds on VSM, utilizing radial arm-maze methods to examine varying aspects of memory. Additionally, brain phytoestrogen, calbindin (CALB, and cyclooxygenase-2 (COX-2 levels were determined. Results Female rats receiving lifelong exposure to a high-phytoestrogen containing diet (Phyto-600 acquired the maze faster than females fed a phytoestrogen-free diet (Phyto-free; in males the opposite diet effect was identified. In a separate experiment, at 80 days-of-age, animals fed the Phyto-600 diet lifelong either remained on the Phyto-600 or were changed to the Phyto-free diet until 120 days-of-age. Following the diet change Phyto-600 females outperformed females switched to the Phyto-free diet, while in males the opposite diet effect was identified. Furthermore, males fed the Phyto-600 diet had significantly higher phytoestrogen concentrations in a number of brain regions (frontal cortex, amygdala & cerebellum; in frontal cortex, expression of CALB (a neuroprotective calcium-binding protein decreased while COX-2 (an inducible inflammatory factor prevalent in Alzheimer's disease increased. Conclusions Results suggest that dietary phytoestrogens significantly sex-reversed the normal sexually dimorphic expression of VSM. Specifically, in tasks requiring the use of reference, but not working, memory, VSM was enhanced in females fed the Phyto-600 diet, whereas, in males VSM was inhibited by the same diet. These findings suggest that dietary soy derived phytoestrogens can influence learning and memory and alter the expression of proteins involved in neural protection and inflammation in rats.

Phytoestrogens: a viable option?

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Russell, Lori; Hicks, G Swink; Low, Annette K; Shepherd, Jinna M; Brown, C Andrew

2002-10-01

Estrogen replacement therapy is one of the most commonly prescribed medicines in the United States by traditional medical professionals. Over the past decade, the market for complementary/ alternative therapies for hormone replacement has dramatically increased. Women are seeking more "natural" alternatives to treat menopausal symptoms. Well-designed randomized clinical trials are often lacking, as is the information on efficacy and safety. This article will review several popular herbal therapies for menopausal symptoms including phytoestrogens, black cohosh (Cimicifuga racemosa), dong quai (Angelica sinensis), chast tree (Vitex agnus-castus), and wild Mexican yam. Their use, mechanism of action, and adverse effects are outlined.

Roles of Dietary Phytoestrogens on the Regulation of Epithelial-Mesenchymal Transition in Diverse Cancer Metastasis

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Lee, Geum-A.; Hwang, Kyung-A.; Choi, Kyung-Chul

2016-01-01

Epithelial-mesenchymal transition (EMT) plays a key role in tumor progression. The cells undergoing EMT upregulate the expression of cell motility-related proteins and show enhanced migration and invasion. The hallmarks of EMT in cancer cells include changed cell morphology and increased metastatic capabilities in cell migration and invasion. Therefore, prevention of EMT is an important tool for the inhibition of tumor metastasis. A novel preventive therapy is needed, such as treatment of natural dietary substances that are nontoxic to normal human cells, but effective in inhibiting cancer cells. Phytoestrogens, such as genistein, resveratrol, kaempferol and 3,3′-diindolylmethane (DIM), can be raised as possible candidates. They are plant-derived dietary estrogens, which are found in tea, vegetables and fruits, and are known to have various biological efficacies, including chemopreventive activity against cancers. Specifically, these phytoestrogens may induce not only anti-proliferation, apoptosis and cell cycle arrest, but also anti-metastasis by inhibiting the EMT process in various cancer cells. There have been several signaling pathways found to be associated with the induction of the EMT process in cancer cells. Phytoestrogens were demonstrated to have chemopreventive effects on cancer metastasis by inhibiting EMT-associated pathways, such as Notch-1 and TGF-beta signaling. As a result, phytoestrogens can inhibit or reverse the EMT process by upregulating the expression of epithelial phenotypes, including E-cadherin, and downregulating the expression of mesenchymal phenotypes, including N-cadherin, Snail, Slug, and vimentin. In this review, we focused on the important roles of phytoestrogens in inhibiting EMT in many types of cancer and suggested phytoestrogens as prominent alternative compounds to chemotherapy. PMID:27231938

Spermatogenic Cell-Specific Gene Mutation in Mice via CRISPR-Cas9.

Science.gov (United States)

Bai, Meizhu; Liang, Dan; Wang, Yinghua; Li, Qing; Wu, Yuxuan; Li, Jinsong

2016-05-20

Tissue-specific knockout technology enables the analysis of the gene function in specific tissues in adult mammals. However, conventional strategy for producing tissue-specific knockout mice is a time- and labor-consuming process, restricting rapid study of the gene function in vivo. CRISPR-Cas9 system from bacteria is a simple and efficient gene-editing technique, which has enabled rapid generation of gene knockout lines in mouse by direct injection of CRISPR-Cas9 into zygotes. Here, we demonstrate CRISPR-Cas9-mediated spermatogenic cell-specific disruption of Scp3 gene in testes in one step. We first generated transgenic mice by pronuclear injection of a plasmid containing Hspa2 promoter driving Cas9 expression and showed Cas9 specific expression in spermatogenic cells. We then produced transgenic mice carrying Hspa2 promoter driven Cas9 and constitutive expressed sgRNA targeting Scp3 gene. Male founders were infertile due to developmental arrest of spermatogenic cells while female founders could produce progeny normally. Consistently, male progeny from female founders were infertile and females could transmit the transgenes to the next generation. Our study establishes a CRISPR-Cas9-based one-step strategy to analyze the gene function in adult tissues by a temporal-spatial pattern. Copyright © 2016 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

The spermatogenic process of the common vampire bat Desmodus rotundus under a histomorphometric view.

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Danielle Barbosa Morais

Full Text Available Among all bat species, Desmodus rotundus stands out as one of the most intriguing due to its exclusively haematophagous feeding habits. However, little is known about their spermatogenic cycle. This study aimed at describing the spermatogenic process of common vampire bats through testicular histomorphometric characterization of adult specimens, spermatogenic production indexes, description of stages of the seminiferous epithelium cycle and estimative of the spermatogenic process duration. Morphometrical and immunohistochemical analyzes for bromodeoxiuridine were conducted under light microscopy and ultrastructural analyzes were performed under transmission electron microscopy. Vampire bats showed higher investment in gonadal tissue (gonadosomatic index of 0.54% and in seminiferous tubules (tubulesomatic index of 0.49% when compared to larger mammals. They also showed a high tubular length per gram of testis (34.70 m. Approximately half of the intertubular compartment was found to be comprised by Leydig cells (51.20%, and an average of 23.77x106 of these cells was found per gram of testis. The germline cells showed 16.93% of mitotic index and 2.51% of meiotic index. The overall yield of spermatogenesis was 60% and the testicular spermatic reserve was 71.44x107 spermatozoa per gram of testis. With a total spermatogenesis duration estimated at 37.02 days, vampire bats showed a daily sperm production of 86.80x106 gametes per gram of testis. These findings demonstrate a high sperm production, which is commonly observed in species with promiscuous mating system.

Phytoestrogens and Their Metabolites in Bulk-Tank Milk: Effects of Farm Management and Season

Science.gov (United States)

Adler, Steffen A.; Purup, Stig; Hansen-Møller, Jens; Thuen, Erling; Steinshamn, Håvard

2015-01-01

Phytoestrogens have structures similar to endogenous steroids and may induce or inhibit the response of hormone receptors. The objectives of the present study were to compare the effects of long-term vs. short-term grassland management in organic and conventional dairy production systems, compare organic and conventional production systems and assess seasonal variation on phytoestrogen concentrations in bulk-tank milk. The concentrations of phytoestrogens were analyzed in bulk-tank milk sampled three times in two subsequent years from 28 dairy farms: Fourteen organic (ORG) dairy farms with either short-term or long-term grassland management were paired with 14 conventional (CON) farms with respect to grassland management. Grassland management varied in terms of time since establishment. Short-term grassland management (SG) was defined as establishment or reseeding every fourth year or more often, and long-term grassland management (LG) was defined as less frequent establishment or reseeding. The proportion of red clover (Trifolium pretense L.) in the herbage was positively correlated with milk concentrations of the mammalian isoflavone equol. Therefore, organically produced bulk-tank milk contained more equol than conventionally produced milk, and milk from ORG-SG farms had more equol than milk from ORG-LG farms. Milk produced during the indoor-feeding periods had more equol than milk produced during the outdoor feeding period, because pastures contained less red clover than fields intended for silage production. Organically produced milk had also higher concentrations of the mammalian lignan enterolactone, but in contrast to equol, concentrations increased in the outdoor-feeding periods compared to the indoor-feeding periods. There were no indications of fertility problems on ORG-SG farms who had the highest red clover proportions in the herbage. This study shows that production system, grassland management, and season affect milk concentrations of phytoestrogens

Phytoestrogens and their metabolites in bulk-tank milk: effects of farm management and season.

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Steffen A Adler

Full Text Available Phytoestrogens have structures similar to endogenous steroids and may induce or inhibit the response of hormone receptors. The objectives of the present study were to compare the effects of long-term vs. short-term grassland management in organic and conventional dairy production systems, compare organic and conventional production systems and assess seasonal variation on phytoestrogen concentrations in bulk-tank milk. The concentrations of phytoestrogens were analyzed in bulk-tank milk sampled three times in two subsequent years from 28 dairy farms: Fourteen organic (ORG dairy farms with either short-term or long-term grassland management were paired with 14 conventional (CON farms with respect to grassland management. Grassland management varied in terms of time since establishment. Short-term grassland management (SG was defined as establishment or reseeding every fourth year or more often, and long-term grassland management (LG was defined as less frequent establishment or reseeding. The proportion of red clover (Trifolium pretense L. in the herbage was positively correlated with milk concentrations of the mammalian isoflavone equol. Therefore, organically produced bulk-tank milk contained more equol than conventionally produced milk, and milk from ORG-SG farms had more equol than milk from ORG-LG farms. Milk produced during the indoor-feeding periods had more equol than milk produced during the outdoor feeding period, because pastures contained less red clover than fields intended for silage production. Organically produced milk had also higher concentrations of the mammalian lignan enterolactone, but in contrast to equol, concentrations increased in the outdoor-feeding periods compared to the indoor-feeding periods. There were no indications of fertility problems on ORG-SG farms who had the highest red clover proportions in the herbage. This study shows that production system, grassland management, and season affect milk concentrations of

Isolation and identification of phytoestrogens and flavonoids in an Ayurvedic proprietary medicine using chromatographic and Mass Spectroscopic analysis

Institute of Scientific and Technical Information of China (English)

Sulaiman CT; Arun A; Anandan EM; Sandhya CR; Indira Balachandran

2015-01-01

Objective: To develop analytical methods for the isolation and structural identification of poly phenols including phytoestrogens in Mensokot tablet, a herbal proprietary medicine. Methods:Isolation consisted of an ultrasound-assisted extraction, followed by acid hydrolysis and a final liquid-liquid extraction step in diethyl ether. Identification and structural characterisation was done by liquid chromatography coupled with Q-TOF-ESI-MS/MS analysis. Results:Phytoestrogens such as Coumestrol, Genistein and Glycitein have been identified in Mensokot tablet along with several other flavonoids. Conclusion: In the present research, a rapid HPLC-MS/MS method has been developed for the identification of phytoestrogens and other flavonoids from an Ayurvedic proprietary medicine. Phytoestrogens are considered to play an important role in the prevention of cancers, heart disease, menopausal symptoms and osteoporosis.

Phytoestrogens and Their Metabolites in Bulk-Tank Milk: Effects of Farm Management and Season

DEFF Research Database (Denmark)

Adler, Steffen A; Purup, Stig; Hansen-Møller, Jens

2015-01-01

Phytoestrogens have structures similar to endogenous steroids and may induce or inhibit the response of hormone receptors. The objectives of the present study were to compare the effects of long-term vs. short-term grassland management in organic and conventional dairy production systems, compare...... organic and conventional production systems and assess seasonal variation on phytoestrogen concentrations in bulk-tank milk. The concentrations of phytoestrogens were analyzed in bulk-tank milk sampled three times in two subsequent years from 28 dairy farms: Fourteen organic (ORG) dairy farms with either...... short-term or long-term grassland management were paired with 14 conventional (CON) farms with respect to grassland management. Grassland management varied in terms of time since establishment. Short-term grassland management (SG) was defined as establishment or reseeding every fourth year or more often...

Sexual selection, genetic conflict, selfish genes, and the atypical patterns of gene expression in spermatogenic cells.

Science.gov (United States)

Kleene, Kenneth C

2005-01-01

This review proposes that the peculiar patterns of gene expression in spermatogenic cells are the consequence of powerful evolutionary forces known as sexual selection. Sexual selection is generally characterized by intense competition of males for females, an enormous variety of the strategies to maximize male reproductive success, exaggerated male traits at all levels of biological organization, co-evolution of sexual traits in males and females, and conflict between the sexual advantage of the male trait and the reproductive fitness of females and the individual fitness of both sexes. In addition, spermatogenesis is afflicted by selfish genes that promote their transmission to progeny while causing deleterious effects. Sexual selection, selfish genes, and genetic conflict provide compelling explanations for many atypical features of gene expression in spermatogenic cells including the gross overexpression of certain mRNAs, transcripts encoding truncated proteins that cannot carry out basic functions of the proteins encoded by the same genes in somatic cells, the large number of gene families containing paralogous genes encoding spermatogenic cell-specific isoforms, the large number of testis-cancer-associated genes that are expressed only in spermatogenic cells and malignant cells, and the overbearing role of Sertoli cells in regulating the number and quality of spermatozoa.

Dietary Phytoestrogen Intake is Inversely Associated with Hypertension in a Cohort of Adults Living in the Mediterranean Area

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Justyna Godos

2018-02-01

Full Text Available Background: Dietary polyphenols, including phytoestrogens are abundantly present in a balanced diet. Evidence for their role in preventing non-communicable diseases is emerging. Methods: We examined the association between estimated habitual intakes of dietary phytoestrogens and hypertension in a cohort study. The baseline data included 1936 men and women aged 18 years and older. Intakes of total phytoestrogens, isoflavones, and lignans were calculated from validated food frequency questionnaire. Data on the polyphenols content in foods were retrieved from the Phenol-Explorer database. Results: Individuals in the highest quartile of dietary phytoestrogens intake were less likely to be hypertensive (OR: 0.66, 95% CI: 0.44–0.98; moreover, the association showed a significant decreasing trend. Isoflavones and lignans were not associated with lower odds of hypertension; however, some individual compounds, such as biochanin A and pinoresinol showed an independent inverse association with hypertension. Conclusions: Dietary phytoestrogens are associated with lower likelihood of hypertension in adults living in the Mediterranean area. Future studies are needed to confirm the present findings (i.e., prospective cohort studies and to better understand the mechanisms underlying such associations.

Effect of low dose radiation on cytochrome c and caspase-3 protein expressions in spermatogenic cells of mouse testis

International Nuclear Information System (INIS)

Wang Zhicheng; Zhao Hongguang; Piao Chunnan; Liu Guangwei; Liu Shuchun; Lv Zhe; Gong Shouliang

2006-01-01

Objective: To investigate the effect of low dose radiation on the expressions of cytochrome e (Cyt c) and caspase-3 proteins in spermatogenic cells of mouse testis. Methods: The relationships of dose- and time-effect of Cyt c and caspase-3 protein expressions with different dose of X-rays were observed in the spermatogenic cells of mouse testis with immunohistochemical technique (SABC). Results: After irradiation with 0, 0.025, 0.05, 0.075, 0.1 and 0.2 Gy, Cyt c and caspase-3 proteins expressed differently in all kinds of spermatogenic cells, and principally in spermatogonia and spermatocytes, and less in spermatids and spermatozoa. And the expressions increased with the increasing of irradiation dose. The expressions of both proteins after irradiation with 0.075 Gy increased with the lapse of time and reached to the peak at 12 h, and then decreased. Conclusion: Dose-and time-effect exists on the low-dose irradiation induced expressions of Cyt e and caspase-3 proteins in spermatogenic cells of mouse testis. (authors)

Redox regulation of fertilisation and the spermatogenic process

Institute of Scientific and Technical Information of China (English)

Junichi Fujii; Satoshi Tsunoda

2011-01-01

Oxidative stress is one of the major causes of male infertility; it damages spermatogenic cells, the spermatogenic process and sperm function. Recent advances in redox biology have revealed the signalling role of reactive oxygen species (ROS) that are generated by cells. While highly reactive oxidants, such as the hydroxyl radical, exert largely deleterious effects, hydrogen peroxide can feasibly serve as a signal mediator because it is moderately reactive and membrane permeable and because it can oxidize only limited numbers of functional groups of biological molecules. The amino acid side chain most sensitive to oxidation is cysteine sulphydryl, which is commonly involved in the catalysis of some enzymes. Although the reactivity of cysteine sulphhydryl is not very high in ordinary proteins, some phosphatases possess a highly reactive sulphydryl group at their catalytic centre and are thereby oxidatively inactivated by transiently elevated hydrogen peroxide levels after extracellular stimuli and under certain environmental conditions. Peroxiredoxins, in turn, show moderate hydrogen peroxide-reducing activity, and their role in the modulation of ROS-mediated signal transduction in ordinary cells, mediated by protecting phosphatases from oxidative inactivation, has attracted much attention. Although knowledge of the signalling role of ROS in the male reproductive system is limited at present, its significance is becoming a focal issue. Here, we present a review of the emerging signalling role of hydrogen peroxide in testes.

Using vaginal cytology to assess the estrogenic activity of phytoestrogen-rich herb.

Science.gov (United States)

Malaivijitnond, Suchinda; Chansri, Kullakanya; Kijkuokul, Pisamai; Urasopon, Nontakorn; Cherdshewasart, Wichai

2006-10-11

To assess the estrogenic activities of synthetic estrogen, synthetic phytoestrogen, Pueraria lobata and three distinct cultivars of Pueraria mirifica, a phytoestrogen-rich herb, a vaginal cytology assay in ovariectomized rats were used. Rats were ovariectomized and treated with DW, estradiol valerate (1 mg/kg BW), genistein (0.25-2.5 mg/kg BW), Pueraria lobata and Pueraria mirifica (10-1,000 mg/kg BW) for 14 days. The vaginal cytology was checked daily and the uteri were dissected and weighed at the end of treatment or post-treatment periods. The treatments of DW, genistein and Pueraria lobata did not influence the vaginal epithelium, but the injection of estradiol valerate induced a vaginal cornification from day-3 of treatment to day-14 of post-treatment period. The occurrence of vaginal cornification after treatment and the recovery after the cessation was dependent on dosages and cultivars of Pueraria mirifica. The increments of uterus weight in all rats agreed with the cornification of vaginal epithelium. Although both uterotropic and vaginal cytology assays can be used to assess the estrogenic activity of phytoestrogen-rich herb, however, using vaginal cytology assay has two advantages: (1) we do not need to kill the animals and (2) we can follow up the recovery after the cessation of treatment.

Occurrence and Profiles of the Artificial Endocrine Disruptor Bisphenol A and Natural Endocrine Disruptor Phytoestrogens in Urine from Children in China

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Mingyue Zhang

2015-11-01

Full Text Available Background: Exposure to artificial or natural endocrine disruptors, such as bisphenol A (BPA and phytoestrogens has been demonstrated to have health effects, especially in children. Biomonitoring of BPA and phytoestrogens in human urine can be used to assess the intake levels of these compounds. Methods: In this study, BPA and phytoestrogens in urine specimens (n = 256 collected from children in China were measured by liquid chromatography (LC-tandem mass spectrometry (MS/MS. Results: BPA was detected in most specimens, with a geometric mean concentration of 1.58 ng/mL. For the first time, levels of urinary phytoestrogens in Chinese children were reported. Daidzein and enterolactone are the typical isoflavones and lignans compounds in urine, respectively. Conclusions: Relatively high levels of urinary BPA indicate an increasing risk of BPA exposure to Chinese children. Urinary concentrations of daidzein in Chinese children are higher when compared with those reported in the U.S. children, while concentrations of urinary enterolactone and enterodiols are significantly lower. This suggests a significant difference in phytoestrogen intake between the children from China and from the U.S.

Phytoestrogens Enhance the Vascular Actions of the Endocannabinoid Anandamide in Mesenteric Beds of Female Rats

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Roxana N. Peroni

2012-01-01

Full Text Available In rat isolated mesenteric beds that were contracted with NA as an in vitro model of the vascular adrenergic hyperactivity that usually precedes the onset of primary hypertension, the oral administration (3 daily doses of either 10 mg/kg genistein or 20 mg/kg daidzein potentiated the anandamide-induced reduction of contractility to NA in female but not in male rats. Oral treatment with phytoestrogens also restored the vascular effects of anandamide as well as the mesenteric content of calcitonin gene-related peptide (CGRP that were reduced after ovariectomy. The enhancement of anandamide effects caused by phytoestrogens was prevented by the concomitant administration of the estrogen receptor antagonist fulvestrant (2.5 mg/kg, s.c., 3 daily doses. It is concluded that, in the vasculature of female rats, phytoestrogens produced an estrogen-receptor-dependent enhancement of the anandamide-vascular actions that involves the modulation of CGRP levels and appears to be relevant whenever an adrenergic hyperactivity occurs.

17 beta-estradiol but not the phytoestrogen naringenin attenuates aortic cholesterol accumulation in WHHL rabbits

DEFF Research Database (Denmark)

Mortensen, Alicja; Breinholt, V.; Dalsgaard, T.

2001-01-01

The effects of 17 beta -estradiol (17 beta -E-2) or the phytoestrogen naringenin on spontaneous atherosclerosis were studied in 36 ovariectomized homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits receiving a semisynthetic control diet; this diet added 0.0040% 17 beta -E-2, or 0.20% nari...... and its antiatherogenic effect. - Mortensen, A., V. Breinholt, T. Dalsgaard, H. Frandsen, S. T. Lauridsen, J. Laigaard, B. Ottesen, and J-J. Larsen. 17 beta -Estradiol but not the phytoestrogen naringenin attenuates aortic cholesterol accumulation in WHHL rabbits.......The effects of 17 beta -estradiol (17 beta -E-2) or the phytoestrogen naringenin on spontaneous atherosclerosis were studied in 36 ovariectomized homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits receiving a semisynthetic control diet; this diet added 0.0040% 17 beta -E-2, or 0.......20% naringenin, for 16 weeks. The uterine weight was increased (P 17 beta -E-2 group compared with the controls. Total plasma cholesterol and triglycerides were not different from those in the controls, In lipoproteins, HDL...

The association between dietary lignans, phytoestrogen-rich foods, and fiber intake and postmenopausal breast cancer risk: a German case-control study

NARCIS (Netherlands)

Zaineddin, A.K.; Buck, K.; Vrieling, A.; Heinz, J.; Flesch-Janys, D.; Linseisen, J.; Chang-Claude, J.

2012-01-01

Phytoestrogens are structurally similar to estrogens and may affect breast cancer risk by mimicking estrogenic/antiestrogenic properties. In Western societies, whole grains and possibly soy foods are rich sources of phytoestrogens. A population-based case-control study in German postmenopausal women

Adenylate cyclase regulation in the spermatogenic cell plasma membrane: Modulating effects of TPA and TCDD

International Nuclear Information System (INIS)

Beebe, L.E.

1989-01-01

This research was designed to compare the effects of TPA, a phorbol ester, and TCDD in a spermatogenic cell population, a target of TCDD toxicity. Membrane-bound adenylate cyclase activity was used an index of membrane function, and was quantified by the amount of 32 P-cAMP formed from 32 P-ATP following chromatographic separation. Exposure to male germ cells in-vitro to TPA and TCDD followed by direct measurement of enzyme activity was used to investigate the potential of each agent to perturb membrane function. TPA and TCDD consistently inhibited adenylate cyclase activity at the levels of G s -catalytic unit coupling and hormone-receptor activation, as measured by the stimulation of enzyme activity by concomitant addition of forskolin and GTP and FSH and GTP, respectively. The effect on coupling required at least 60 minutes of exposure to TPA or TCDD. Concentration-response curves demonstrated a progressive desensitization with increasing TPA concentration, while TCDD exhibited consistent inhibition over the same concentration range

Anti-inflammatory and neuroprotective effect of a phytoestrogen compound on rat microglia.

Science.gov (United States)

Marotta, F; Mao, G S; Liu, T; Chui, D H; Lorenzetti, A; Xiao, Y; Marandola, P

2006-11-01

Ovariectomized Wistar rats received orally 15 mg/kg of a phytoestrogen compound (genistein, daidzein, glycitein, black cohosh, angelica sin., licorice, vitex agnus) for 2 weeks to test its ability to modulate inflammatory microglia response. Microglial proliferation was tested by trypan blue and by absorbance. Serial supernatant sampling was performed for 24 h to check TNF-alpha, IL-beta, IL-6, and TGF-beta. LPS caused a time course increase of all cytokines, with IL-beta and TNF-alpha peaking at the 12th hour, whereas IL-6 and TGF-beta peaked at the 24 h observation. Rats fed with the phytoestrogen displayed a significantly lower level of proinflammatory cytokines and a higher level of TGF-beta, as shown also by Western blot analysis. This finding may offer promise in the field of nutraceutical intervention.

Spermatogenic structure and fertility of Mus musculus after exposure of mangosteen (Garcinia mangostana L) pericarp extract

Science.gov (United States)

Hayati, Alfiah; Agustin, Melia Eka; Rokhimaningrum, Farida Ayu; Adro'i, Hasan; Darmanto, Win

2016-03-01

This study aimed to determine the effect of mangosteen (Garcinia mangostana L.) pericarp extract on spermatogenics number, seminiferous tubules sized, profile protein of epididymal and testicular sperm, and fertility of mice (Mus musculus). Fourty two male mice strain BALB/C was divided equally into 7 groups. The control group was given 0.05 ml of 0.05% CMC solution. Three group were given mangosteen pericarp extract at various doses (75, 100 and 150 mg/kg body weight, respectively) for 7 days, while the other three groups were given the same extract dose for 35 days. Parameters evaluated on histological of spermatogonia, spermatocytes, round spermatids, seminiferous tubule diameter, and thickness of germinal epithelium, analysis of testicular and epidydimal protein profile with SDS-Page, and than fertility test on female mice. The results showed that mangosteen pericarp extract at 75 and 100 mg/kg dose for 7 days had no effect on spermatogenics number and seminiferous tubule sizes, but the treatment dose of 150 mg/kg for 7 days and all treatment (doses of 75, 100, and 150 mg/kg) for 35 days led to significant decrease on the number of spermatogenics and seminiferous tubule sizes; effect on protein profiles testicular and epididymal sperm; and lower fertilization.

Phytoestrogens and mycotoxins in Iowa streams: An examination of underinvestigated compounds in agricultural basins

Science.gov (United States)

Kolpin, Dana W.; Hoerger, Corinne C.; Meyer, Michael T.; Wettstein, Felix E.; Hubbard, Laura E.; Bucheli, Thomas D.

2010-01-01

This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km2 to >836,000 km2 Atrazine (herbicide) also was measured in all samples as a frame-of-reference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). The nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L-1 (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly take place in surface water are poorly understood and have yet to be

Effect of Bcl-2/Bax gene expression on apoptosis of spermatogenic cells of mouse testes induced by low dose radiation

International Nuclear Information System (INIS)

Liu Guangwei; Wang Chunyan; Lu Zhe; Liu Shunchun; Gong Shouliang

2003-01-01

The different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptosis and Bcl-2 and Bax protein expression were measured with flow cytometry and immunohistochemical method, respectively. The results showed the apoptosis in all kinds of spermatogenic cells induced by low dose radiation (LDR) had a obvious regularity. When the doses were 0.025 and 0.05 Gy, spermatogonia apoptosis was dominant. With the increase of irradiation dose (0.075-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic percentage of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarcely occurred after LDR. Bax protein was primarily expressed in spermatogonia and spermatocytes, and the former was significantly higher than that of the latter after LDR. With the increase of irradiation dose, Bax protein expression showed a upgrading tendency, but that of spermatids and spermatozoa scarcely occurred. Bcl-2 protein was primarily expressed in spermatids and spermatozoa, but the Bcl-2 protein expressions of spermatogonia and spermatocytes scarcely occurred after LDR. These results imply that the interacting regulation of Bcl-2 and Bax gene expression might be involved in selective apoptosis of spermatogenic cells induced by LDR, which provided an experimental evidence for further exploring the apoptotic mechanism of adaptive response of spermatogenic cells by LDR

Transport of steroid hormones, phytoestrogens, and estrogenic activity across a swine lagoon/sprayfield system.

Science.gov (United States)

Yost, Erin E; Meyer, Michael T; Dietze, Julie E; Williams, C Michael; Worley-Davis, Lynn; Lee, Boknam; Kullman, Seth W

2014-10-07

The inflow, transformation, and attenuation of natural steroid hormones and phytoestrogens and estrogenic activity were assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet, particularly, daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at 2 months postapplication. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone was found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a livestock lagoon/sprayfield and provides global insight into the fate of these analytes in this widely used waste management system.

Coumestrol and its metabolite in mares' plasma after ingestion of phytoestrogen-rich plants: potent endocrine disruptors inducing infertility.

Science.gov (United States)

Ferreira-Dias, G; Botelho, M; Zagrajczuk, A; Rebordão, M R; Galvão, A M; Bravo, P Pinto; Piotrowska-Tomala, K; Szóstek, A Z; Wiczkowski, W; Piskula, M; Fradinho, M J; Skarzynski, D J

2013-10-01

Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n = 14) kept on clover and grass-mixed pastures, and supplemented with concentrate and hay or cereal straw. Blood and feedstuff were obtained from November to March. In experiment II, stabled cyclic Lusitano mares (n = 6) were fed for 14 days with increasing amounts of alfalfa pellets (250 g to 1 kg/day). Sequential blood samples were obtained for 8 hours after feed intake on Day 0 (control) and on Days 13 and 14 (1 kg/day alfalfa pellets). Experiment III mares were fed with a mixture of alfalfa and clover haylage for 5 months (group 1; n = 4) or for 9 months (group 2; n = 12). Estrous cycle was determined on the basis of plasma estradiol (E2), progesterone (P4), and ultrasound (experiment III). Concentrations of phytoestrogen coumestrol and its metabolite methoxycoumestrol were determined by high-performance liquid chromatography coupled with mass spectrometry. Phytoestrogens decreased in pasture from November until March (P haylage) than in group 1, after haylage withdrawal (P < 0.001). These data show that in the mare, coumestrol and its metabolite increase in blood after ingestion of estrogenic plants and can influence reproduction in mares as potent endocrine disruptors. Copyright © 2013 Elsevier Inc. All rights reserved.

The influence of snakehead (Channa striata) fish extract to increase hyperglycemic mice fertility based on spermatogenic cell composition

Science.gov (United States)

Hidayati, Dewi; Abdulgani, Nurlita; Ashuri, Nova Maulidina; Sa'adah, Noor Nailis; Lukitasari, Maharani

2017-06-01

Reproductive dysfunction is recognized as a consequence of diabetes mellitus. Previous study revealed that snakehead (Channa striata) fish extract can repairing the pancreas histological structure which by that decreasing the blood glucose levels. Further research was conducted to determine the influence of snakehead fish extract (SHFE) to increasing the fertility of hyperglycemic mice based on spermatogenic cell composition. Twenty five adult mice (Mus musculus) were induced intraperitoneally to be hyperglycemic using alloxan monohydrate single dose of 190 mg/kg body weight. Hyperglycemic mice treated orally for 14 days using SHFE which grouped into five treatment dosages. Testicular histology were prepared using the paraffin methods and stained with Haematoxylin and Eosin. According to ANOVA and Tukey's test, it was found that spermatogenic cells population as well as its composition in the testis of mice that treated with SHFE are significantly higher than hyperglichemic mice. The highest dose of SHFE (0.15 ml/day), showed highest spermatogenic cell. All hyperglichemic mice that treated with SHFE exhibited the ratio composition of spermatogonia: spermatocytes: spermatids as same as with control (healthy mice) i.e. 1:1:3 respectively.

Therapeutic Perspectives of 8-Prenylnaringenin, a Potent Phytoestrogen from Hops

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Kateřina Štulíková

2018-03-01

Full Text Available Hop (Humulus lupulus L., as a key ingredient for beer brewing, is also a source of many biologically active molecules. A notable compound, 8-prenylnaringenin (8-PN, structurally belonging to the group of prenylated flavonoids, was shown to be a potent phytoestrogen, and thus, became the topic of active research. Here, we overview the pharmacological properties of 8-PN and its therapeutic opportunities. Due to its estrogenic effects, administration of 8-PN represents a novel therapeutic approach to the treatment of menopausal and post-menopausal symptoms that occur as a consequence of a progressive decline in hormone levels in women. Application of 8-PN in the treatment of menopause has been clinically examined with promising results. Other activities that have already been assessed include the potential to prevent bone-resorption or inhibition of tumor growth. On the other hand, the use of phytoestrogens is frequently questioned regarding possible adverse effects associated with long-term consumption. In conclusion, we emphasize the implications of using 8-PN in future treatments of menopausal and post-menopausal symptoms, including the need for precise evidence and further investigations to define the safety risks related to its therapeutic use.

Phytoestrogens in menopausal supplements induce ER-dependent cell proliferation and overcome breast cancer treatment in an in vitro breast cancer model

International Nuclear Information System (INIS)

Duursen, Majorie B.M. van; Smeets, Evelien E.J.W.; Rijk, Jeroen C.W.; Nijmeijer, Sandra M.; Berg, Martin van den

2013-01-01

Breast cancer treatment by the aromatase inhibitor Letrozole (LET) or Selective Estrogen Receptor Modulator Tamoxifen (TAM) can result in the onset of menopausal symptoms. Women often try to relieve these symptoms by taking menopausal supplements containing high levels of phytoestrogens. However, little is known about the potential interaction between these supplements and breast cancer treatment, especially aromatase inhibitors. In this study, interaction of phytoestrogens with the estrogen receptor alpha and TAM action was determined in an ER-reporter gene assay (BG1Luc4E2 cells) and human breast epithelial tumor cells (MCF-7). Potential interactions with aromatase activity and LET were determined in human adrenocorticocarcinoma H295R cells. We also used the previously described H295R/MCF-7 co-culture model to study interactions with steroidogenesis and tumor cell proliferation. In this model, genistein (GEN), 8-prenylnaringenin (8PN) and four commercially available menopausal supplements all induced ER-dependent tumor cell proliferation, which could not be prevented by physiologically relevant LET and 4OH-TAM concentrations. Differences in relative effect potencies between the H295R/MCF-7 co-culture model and ER-activation in BG1Luc4E2 cells, were due to the effects of the phytoestrogens on steroidogenesis. All tested supplements and GEN induced aromatase activity, while 8PN was a strong aromatase inhibitor. Steroidogenic profiles upon GEN and 8PN exposure indicated a strong inhibitory effect on steroidogenesis in H295R cells and H295R/MCF-7 co-cultures. Based on our in vitro data we suggest that menopausal supplement intake during breast cancer treatment should better be avoided, at least until more certainty regarding the safety of supplemental use in breast cancer patients can be provided. - Highlights: • Supplements containing phytoestrogens are commonly used by women with breast cancer. • Phytoestrogens alter steroidogenesis in a co-culture breast

Phytoestrogens in menopausal supplements induce ER-dependent cell proliferation and overcome breast cancer treatment in an in vitro breast cancer model

Energy Technology Data Exchange (ETDEWEB)

Duursen, Majorie B.M. van, E-mail: M.vanDuursen@uu.nl [Endocrine Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, PO Box 80177, 3508 TD, Utrecht (Netherlands); Smeets, Evelien E.J.W. [Endocrine Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, PO Box 80177, 3508 TD, Utrecht (Netherlands); Rijk, Jeroen C.W. [RIKILT - Institute for Food Safety, Wageningen UR, P.O. Box 230, 6700 AE, Wageningen (Netherlands); Nijmeijer, Sandra M.; Berg, Martin van den [Endocrine Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, PO Box 80177, 3508 TD, Utrecht (Netherlands)

2013-06-01

Breast cancer treatment by the aromatase inhibitor Letrozole (LET) or Selective Estrogen Receptor Modulator Tamoxifen (TAM) can result in the onset of menopausal symptoms. Women often try to relieve these symptoms by taking menopausal supplements containing high levels of phytoestrogens. However, little is known about the potential interaction between these supplements and breast cancer treatment, especially aromatase inhibitors. In this study, interaction of phytoestrogens with the estrogen receptor alpha and TAM action was determined in an ER-reporter gene assay (BG1Luc4E2 cells) and human breast epithelial tumor cells (MCF-7). Potential interactions with aromatase activity and LET were determined in human adrenocorticocarcinoma H295R cells. We also used the previously described H295R/MCF-7 co-culture model to study interactions with steroidogenesis and tumor cell proliferation. In this model, genistein (GEN), 8-prenylnaringenin (8PN) and four commercially available menopausal supplements all induced ER-dependent tumor cell proliferation, which could not be prevented by physiologically relevant LET and 4OH-TAM concentrations. Differences in relative effect potencies between the H295R/MCF-7 co-culture model and ER-activation in BG1Luc4E2 cells, were due to the effects of the phytoestrogens on steroidogenesis. All tested supplements and GEN induced aromatase activity, while 8PN was a strong aromatase inhibitor. Steroidogenic profiles upon GEN and 8PN exposure indicated a strong inhibitory effect on steroidogenesis in H295R cells and H295R/MCF-7 co-cultures. Based on our in vitro data we suggest that menopausal supplement intake during breast cancer treatment should better be avoided, at least until more certainty regarding the safety of supplemental use in breast cancer patients can be provided. - Highlights: • Supplements containing phytoestrogens are commonly used by women with breast cancer. • Phytoestrogens alter steroidogenesis in a co-culture breast

Improvements of insulin resistance in ovariectomized rats by a novel phytoestrogen from Curcuma comosa Roxb

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Prasannarong Mujalin

2012-03-01

Full Text Available Abstract Background Curcuma comosa Roxb. (C. comosa is an indigenous medicinal herb that has been used in Thailand as a dietary supplement to relieve postmenopausal symptoms. Recently, a novel phytoestrogen, (3R-1,7-diphenyl-(4E,6E-4,6-heptadien-3-ol or compound 049, has been isolated and no study thus far has investigated the role of C. comosa in preventing metabolic alterations occurring in estrogen-deprived state. The present study investigated the long-term effects (12 weeks of C. comosa hexane extract and compound 049 on insulin resistance in prolonged estrogen-deprived rats. Methods Female Sprague-Dawley rats were ovariectomized (OVX and treated with C. comosa hexane extract (125 mg, 250 mg, or 500 mg/kg body weight (BW and compound 049 (50 mg/kg BW intraperitoneally three times per week for 12 weeks. Body weight, food intake, visceral fat weight, uterine weight, serum lipid profile, glucose tolerance, insulin action on skeletal muscle glucose transport activity, and GLUT-4 protein expression were determined. Results Prolonged ovariectomy resulted in dyslipidemia, impaired glucose tolerance and insulin-stimulated skeletal muscle glucose transport, as compared to SHAM. Treatment with C. comosa hexane extract and compound 049, three times per week for 12 weeks, markedly reduced serum total cholesterol and low-density lipoprotein levels, improved insulin sensitivity and partially restored uterine weights in ovariectomized rats. In addition, compound 049 or high doses of C. comosa hexane extract enhanced insulin-mediated glucose uptake in skeletal muscle and increased muscle GLUT-4 protein levels. Conclusions Treatment with C. comosa and its diarylheptanoid derivative improved glucose and lipid metabolism in estrogen-deprived rats, supporting the traditional use of this natural phytoestrogen as a strategy for relieving insulin resistance and its related metabolic defects in postmenopausal women.

Comprehensive assessment of hormones, phytoestrogens, and estrogenic activity in an anaerobic swine waste lagoon

Science.gov (United States)

Yost, Erin E.; Meyer, Michael T.; Dietze, Julie E.; Meissner, Benjamin M.; Williams, Mike; Worley-Davis, Lynn; Lee, Boknam; Kullman, Seth W.

2013-01-01

In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally towards total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer.

Association between Dietary Share of Ultra-Processed Foods and Urinary Concentrations of Phytoestrogens in the US.

Science.gov (United States)

Martínez Steele, Eurídice; Monteiro, Carlos A

2017-02-28

The aim of this study was to examine the relationship between dietary contribution of ultra-processed foods and urinary phytoestrogen concentrations in the US. Participants from cross-sectional 2009-2010 National Health and Nutrition Examination Survey aged 6+ years, selected to measure urinary phytoestrogens and with one 24-h dietary recall were evaluated (2692 participants). Food items were classified according to NOVA (a name, not an acronym), a four-group food classification based on the extent and purpose of industrial food processing. Ultra-processed foods are formulations manufactured using several ingredients and a series of processes (hence "ultra-processed"). Most of their ingredients are lower-cost industrial sources of dietary energy and nutrients, with additives used for the purpose of imitating sensorial qualities of minimally processed foods or of culinary preparations of these foods. Studied phytoestrogens included lignans (enterolactone and enterodiol) and isoflavones (genistein, daidzein, O -desmethylangolensin and equol). Gaussian regression was used to compare average urinary phytoestrogen concentrations (normalized by creatinine) across quintiles of energy share of ultra-processed foods. Models incorporated survey sample weights and were adjusted for age, sex, race/ethnicity, family income, and education, among other factors. Adjusted enterodiol geometric means decreased monotonically from 60.6 in the lowest quintile to 35.1 µg/g creatinine in the highest, while adjusted enterolactone geometric means dropped from 281.1 to 200.1 across the same quintiles, respectively. No significant linear trend was observed in the association between these quintiles and isoflavone concentrations. This finding reinforces the existing evidence regarding the negative impact of ultra-processed food consumption on the overall quality of the diet and expands it to include non-nutrients such as lignans.

Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

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Pavlína Hloucalová

2016-07-01

Full Text Available The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety “Amos”, alfalfa (variety “Holyně”, and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography–mass spectrometry (LC-MS. Higher levels ( p < 0.05 of isoflavones biochanin A (3.697 mg·g −1 of dry weight and formononetin (4.315 mg·g −1 of dry weight were found in red clover than in other species. The highest isoflavone content was detected in red clover, reaching 1.001% of dry matter ( p < 0.05, representing a risk for occurrence of reproduction problems and inhibited secretion of animal estrogen. The phytoestrogen content was particularly increased in wilted forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest.

Effects of feeding dairy cows different legume-grass silages on milk phytoestrogen concentration

DEFF Research Database (Denmark)

Höjer, A; Adler, S; Purup, Stig

2012-01-01

interval of legume-grass silage on phytoestrogen intake and milk phytoestrogen concentrations. In one experiment, 15 Swedish Red dairy cows were fed 2- or 3-cut red clover-grass silage, or 2-cut birdsfoot trefoil-grass silage. In a second experiment, 16 Norwegian Red dairy cows were fed short-term ley...... red clover-grass silage diet (1,494μg/kg of milk). Because of the metabolism of biochanin A, genistein, and prunetin, their concentrations in milk and the apparent recovery were low. Coumestrol was detected in only short-term and long-term ley silage mixtures, and its milk concentration was low....... Concentrations of secoisolariciresinol and matairesinol were higher in 2-cut birdsfoot trefoil-grass and long-term ley silage mixtures, those with legume species other than red clover, and the highest grass proportions. The 2-cut birdsfoot trefoil-grass silage diet also resulted in higher enterolactone...

Cellular regulation of basal and FSH-stimulated cyclic AMP production in irradiated rat testes

International Nuclear Information System (INIS)

Kangasniemi, M.; Kaipia, A.; Toppari, J.; Mali, P.; Huhtaniemi, I.; Parvinen, M.

1990-01-01

Basal and follicle-stimulating hormone (FSH)-stimulated cyclic AMP (cAMP) productions by seminiferous tubular segments from irradiated adult rats were investigated at defined stages of the epithelial cycle when specific spermatogenic cells were low in number. Seven days post-irradiation, depletion of spermatogonia did not influence the basal cAMP production, but FSH response increased in stages II-VIII. Seventeen days post-irradiation when spermatocytes were low in number, there was a small increase in basal cAMP level in stages VII-VIII and FSH-stimulated cAMP production increased in stages VII-XII and XIII-I. At 38 days when pachytene spermatocytes and round spermatids (steps 1-6) were low in number, a decreased basal cAMP production was measured in stages II-VI and IX-XII. FSH-stimulated cAMP output increased in stages VII-XII but decreased in stages II-VI. At 52 days when all spermatids were low in number, basal cAMP levels decreased in all stages of the cycle, whereas FSH response was elevated only in stages VII-XII. All spermatogenic cell types seem to have an effect on cAMP production by the seminiferous tubule in a stage-specific fashion. Germ cells appear to regulate Sertoli cell FSH response in a paracrine way, and a part of cAMP may originate from spermatids stimulated by an unknown FSH-dependent Sertoli cell factor. The FSH-dependent functions may control such phenomena as spermatogonial proliferation, final maturation of spermatids, and onset of meiosis

Vitamin E and Lycopene Reduce Coal Burning Fluorosis-induced Spermatogenic Cell Apoptosis via Oxidative Stress-mediated JNK and ERK Signaling Pathways.

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Tian, Yuan; Xiao, Yuehai; Wang, Bolin; Sun, Chao; Tang, Kaifa; Sun, Fa

2017-12-22

Although fluoride has been widely used in toothpaste, mouthwash, and drinking water to prevent dental caries, the excessive intake of fluoride can cause fluorosis which is associated with dental, skeletal, and soft tissue fluorosis. Recent evidences have drawn the attention to its adverse effects on male reproductive system that include spermatogenesis defect, sperm count loss, and sperm maturation impairment. Fluoride induces oxidative stress through the activation of mitogen activated protein kinase (MAPK) cascade which can lead to cell apoptosis. Vitamin E (VE) and lycopene are two common anti-oxidants, being protective to reactive oxygen species (ROS)-induced toxic effects. However, whether and how these two anti-oxidants prevent fluoride-induced spermatogenic cell apoptosis are largely unknown. In the present study, a male rat model for coal burning fluorosis was established and the histological lesions and spermatogenic cell apoptosis in rat testes were observed. The decreased expression of clusterin, a heterodimeric glycoprotein reported to regulate spermatogenic cell apoptosis, is detected in fluoride-treated rat testes. Interestingly, the co-administration with VE or lycopene reduced fluorosis-mediated testicular toxicity and rescued clusterin expression. Further, fluoride caused the enhanced Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase (ERK) phosphorylation, which was reduced by VE or lycopene. Thus, VE and lycopene prevent coal burning fluorosis-induced spermatogenic cell apoptosis through the suppression of oxidative stress-mediated JNK and ERK signaling pathway, which could be an alternative therapeutic strategy for the treatment of fluorosis. ©2017 The Author(s).

The expression of Smad4 after radiation of electromagnetic pulses and apoptosis in spermatogenic cells in mouse

International Nuclear Information System (INIS)

Ji Xinxin; Hou Wugang; Zhao Jie; Zhao Yong; Li Wei; Zhang Yuanqiang

2007-01-01

The aim of the study was to investigate the relationships between apoptosis induced by radiation of electromagnetic pulses (EMP) and the expression of Smad4 in mouse spermatogenic cells. 40 adult Balb/c mice were used, and 20 were irradiated with whole-body 400kV/m EMP. The mice were sacrificed and specimens were harvested at 1, 7, 14, 21 and 28 days after the irradiation. Histological changes were observed through Hematoxylin-Eosin staining (H-E staining), the apoptosis of spermatogenic cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method (TUNEL method) and the Smad4 expression was observed using immunohistochemistry SABC methods. Severe injuries were observed 1 day after the radiation and seminiferous epithelium was mostly recovered 28d after the radiation. The localization of smad4 was significantly different in EMP group compared to the control group, and the expression densities of smad4 decreased significantly at 7, 14 and 21d after irradiation (p<0.05). TUNEL assays demonstrated that there was a significant increase in the mean apoptotic index (AI) in irradiation groups than that of control groups (p<0.01). The results suggested that Smad4 and TGF-13/Smad signal pathway might play an important role in spermatogenic cells apoptosis induced by radiation of EMP. (authors)

[Phytoestrogens in the treatment of menopause].

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Remport, Júlia; Blázovics, Anna

2017-08-01

In previous centuries many women did not even live until their menopause years due to poor economic conditions, deficiencies of medicine, epidemics and wars. Nowadays in the developed countries, people live until they are 75-80 years old, and with the expansion of average age, the number of people affected by menopause and the years spent in that state increase. Nowadays women spend one third of their lives in the menopausal stage. The only effective way to treat unpleasant symptoms for centuries was with the use of herbs, and the knowledge about them spread through oral tradition. In the 20th century, this therapeutic form was pushed into the background by the development of synthetic drug production and the introduction of hormone replacement therapy. Thanks to the influence of media in the 20th century, women began to have the social need for preserving their beauty and youth for as long as they could. Hormone replacement therapy enjoyed great popularity because women were temporarily relieved of their life quality-impairing menopausal symptoms, but years later it turned out that hormone replacement therapy could pose serious risks. A distinct advantage of herbal therapy is the more advantageous side-effect-profile opposite the used synthetics in hormone replacement therapy. Women are therefore happy to turn to valuable and well-tried natural therapies, which have been used for thousands of years. There is growing interest in herbal remedies. Studying the effects of phytoestrogens has now become an active area for research. However, the results of studies in animals and humans are controversial, some sources suggest that phytoestrogens are effective and safe, other authors claim that they are ineffective in menopause or they have particularly dangerous properties, and cannot be recommended to everyone. It is important to address this issue for the sake of health, mental health and safety of women, and so it is necessary to assess the benefits and the risks

Association between Dietary Share of Ultra-Processed Foods and Urinary Concentrations of Phytoestrogens in the US

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Eurídice Martínez Steele

2017-02-01

Full Text Available The aim of this study was to examine the relationship between dietary contribution of ultra-processed foods and urinary phytoestrogen concentrations in the US. Participants from cross-sectional 2009–2010 National Health and Nutrition Examination Survey aged 6+ years, selected to measure urinary phytoestrogens and with one 24-h dietary recall were evaluated (2692 participants. Food items were classified according to NOVA (a name, not an acronym, a four-group food classification based on the extent and purpose of industrial food processing. Ultra-processed foods are formulations manufactured using several ingredients and a series of processes (hence “ultra-processed”. Most of their ingredients are lower-cost industrial sources of dietary energy and nutrients, with additives used for the purpose of imitating sensorial qualities of minimally processed foods or of culinary preparations of these foods. Studied phytoestrogens included lignans (enterolactone and enterodiol and isoflavones (genistein, daidzein, O-desmethylangolensin and equol. Gaussian regression was used to compare average urinary phytoestrogen concentrations (normalized by creatinine across quintiles of energy share of ultra-processed foods. Models incorporated survey sample weights and were adjusted for age, sex, race/ethnicity, family income, and education, among other factors. Adjusted enterodiol geometric means decreased monotonically from 60.6 in the lowest quintile to 35.1 µg/g creatinine in the highest, while adjusted enterolactone geometric means dropped from 281.1 to 200.1 across the same quintiles, respectively. No significant linear trend was observed in the association between these quintiles and isoflavone concentrations. This finding reinforces the existing evidence regarding the negative impact of ultra-processed food consumption on the overall quality of the diet and expands it to include non-nutrients such as lignans.

[Chinese medicinal monomer and compound for 60Co-gamma-induced spermatogenic disturbance in mice].

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Zhang, Wei-xing; Wang, Hua-li; Wang, Rui; Li, Rui; He, Wei; Zhang, Tian-biao

2010-05-01

To explore the effects of the monomer and compound of the Chinese herbal drugs resveratrol, lycium barbarum polysaccharide (LBP) and icariin on 60Co-gamma-induced spermatogenic disturbance in mice based on the theory of modern Chinese medicine. A total of 105 male Kunming mice were randomly divided into seven groups, with 15 in each. Group A were normally raised and Groups B, C, D, E, F and G irradiated by 60Co-gamma 6 Gy followed by 60Co-gamma 4 Gy at the interval of 7 days. A week later, Groups C, D, E, F and G received intragastrically the suspension of resveratrol, resveratrol + LBP, resveratrol + icariin, resveratrol + LBP + icariin and resveratrol + LBP + icariin + L-carnitine, respectively, at the dose of 80 mg/(kg x d) for 60 days. The general condition, physical signs and body weight changes of the mice were recorded, and 24 hours after the intragastric medication, their testes were harvested to obtain the testicular weight and indexes, the levels of FSH, LH, T and E2 determined by ELISA, the T/E2 ratio calculated, and the histology of the testis tissues observed under the microscope. The testicular indexes of the mice were decreased by radiation-induced damage, but restored to some extent after intragastric medication, especially in Groups E, F and G. The levels of FSH, LH and T were obviously improved by LBP. The T level and testis weight were increased by Icariin. The level of T/E2 was elevated in Groups E, F and G. The best results were achieved in Group F, which exhibited almost complete recovery from reproductive endocrine disorder and spermatogenic damage. The Chinese medicinal monomer is effective for 60Co-gamma-induced spermatogenic disturbance in mice, and the compound suspension of resveratrol + LBP + icariin produces the best result.

The association between dietary lignans, phytoestrogen-rich foods, and fiber intake and postmenopausal breast cancer risk: a German case-control study.

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Zaineddin, Aida Karina; Buck, Katharina; Vrieling, Alina; Heinz, Judith; Flesch-Janys, Dieter; Linseisen, Jakob; Chang-Claude, Jenny

2012-01-01

Phytoestrogens are structurally similar to estrogens and may affect breast cancer risk by mimicking estrogenic/antiestrogenic properties. In Western societies, whole grains and possibly soy foods are rich sources of phytoestrogens. A population-based case-control study in German postmenopausal women was used to evaluate the association of phytoestrogen-rich foods and dietary lignans with breast cancer risk. Dietary data were collected from 2,884 cases and 5,509 controls using a validated food-frequency questionnaire, which included additional questions phytoestrogen-rich foods. Associations were assessed using conditional logistic regression. All analyses were adjusted for relevant risk and confounding factors. Polytomous logistic regression analysis was performed to evaluate the associations by estrogen receptor (ER) status. High and low consumption of soybeans as well as of sunflower and pumpkin seeds were associated with significantly reduced breast cancer risk compared to no consumption (OR = 0.83, 95% CI = 0.70-0.97; and OR = 0.66, 95% CI = 0.77-0.97, respectively). The observed associations were not differential by ER status. No statistically significant associations were found for dietary intake of plant lignans, fiber, or the calculated enterolignans. Our results provide evidence for a reduced postmenopausal breast cancer risk associated with increased consumption of sunflower and pumpkin seeds and soybeans.

Dietary supplementation of soy germ phytoestrogens or estradiol improves spatial memory performance and increases gene expression of BDNF, TrkB receptor and synaptic factors in ovariectomized rats

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Li Zhuoneng

2010-09-01

Full Text Available Abstract Background Estrogen or phytoestrogens treatment has been suggested to improve cognitive function of the brain in postmenopausal women. However, there is lack of information on the mechanism of such treatment on the central nervous system. The present study aimed to determine the effects of estradiol and soy germ phytoestrogens on spatial memory performance in ovariectomized rats and to explore the underlying mechanisms affecting the central nervous system. Methods Ovariectomized Sprague-Dawley rats were fed a basic diet supplemented with soy germ phytoestrogens (0.4 g/kg or 1.6 g/kg or 17β-estradiol (0.15 g/kg for 12 weeks. At the end of the experiment, animals were evaluated for their spatial learning and memory performance by the Morris Water Maze task. The expressions of brain-derived neurotrophic factor (BDNF and synaptic formation proteins in the hippocampal tissue were estimated using RT-PCR and ELISA. Results It was found that rats supplemented with soy germ phytoestrogens or estradiol performed significantly better in spatial memory acquisition and retention when compared to the rats fed on the control diet. Estradiol or the high dose of phytoestrogens treatment significantly increased BDNF concentration and the mRNA levels for BDNF and its TrkB receptors as well as the synaptic formation proteins, synaptophysin, spinophilin, synapsin 1 and PSD-95, in the hippocampal tissue of the experimental animals. It was also found that phytoestrogens, in contrast to estradiol, did not show any significant effect on the vaginal and uteri. Conclusion Soy germ phytoestrogens, which may be a substitute of estradiol, improved spatial memory performance in ovariectomized rats without significant side-effects on the vaginal and uteri. The memory enhancement effect may relate to the increase in BDNF and the synaptic formation proteins expression in the hippocampus of the brain.

Detection of transgenerational spermatogenic inheritance of adult male acquired CNS gene expression characteristics using a Drosophila systems model.

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Abhay Sharma

Full Text Available Available instances of inheritance of epigenetic transgenerational phenotype are limited to environmental exposures during embryonic and adult gonadal development. Adult exposures can also affect gametogenesis and thereby potentially result in reprogramming of the germline. Although examples of epigenetic effects on gametogenesis exist, it is notable that transgenerational inheritance of environment-induced adult phenotype has not yet been reported. Epigenetic codes are considered to be critical in neural plasticity. A Drosophila systems model of pentylenetetrazole (PTZ induced long-term brain plasticity has recently been described. In this model, chronic PTZ treatment of adult males causes alterations in CNS transcriptome. Here, we describe our search for transgenerational spermatogenic inheritance of PTZ induced gene expression phenotype acquired by adult Drosophila males. We generated CNS transcriptomic profiles of F(1 adults after treating F(0 adult males with PTZ and of F(2 adults resulting from a cross between F(1 males and normal females. Surprisingly, microarray clustering showed F(1 male profile as closest to F(1 female and F(0 male profile closest to F(2 male. Differentially expressed genes in F(1 males, F(1 females and F(2 males showed significant overlap with those caused by PTZ. Interestingly, microarray evidence also led to the identification of upregulated rRNA in F(2 males. Next, we generated microarray expression profiles of adult testis from F(0 and F(1 males. Further surprising, clustering of CNS and testis profiles and matching of differentially expressed genes in them provided evidence of a spermatogenic mechanism in the transgenerational effect observed. To our knowledge, we report for the first time detection of transgenerational spermatogenic inheritance of adult acquired somatic gene expression characteristic. The Drosophila systems model offers an excellent opportunity to understand the epigenetic mechanisms underlying

Detection of transgenerational spermatogenic inheritance of adult male acquired CNS gene expression characteristics using a Drosophila systems model.

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Sharma, Abhay; Singh, Priyanka

2009-06-02

Available instances of inheritance of epigenetic transgenerational phenotype are limited to environmental exposures during embryonic and adult gonadal development. Adult exposures can also affect gametogenesis and thereby potentially result in reprogramming of the germline. Although examples of epigenetic effects on gametogenesis exist, it is notable that transgenerational inheritance of environment-induced adult phenotype has not yet been reported. Epigenetic codes are considered to be critical in neural plasticity. A Drosophila systems model of pentylenetetrazole (PTZ) induced long-term brain plasticity has recently been described. In this model, chronic PTZ treatment of adult males causes alterations in CNS transcriptome. Here, we describe our search for transgenerational spermatogenic inheritance of PTZ induced gene expression phenotype acquired by adult Drosophila males. We generated CNS transcriptomic profiles of F(1) adults after treating F(0) adult males with PTZ and of F(2) adults resulting from a cross between F(1) males and normal females. Surprisingly, microarray clustering showed F(1) male profile as closest to F(1) female and F(0) male profile closest to F(2) male. Differentially expressed genes in F(1) males, F(1) females and F(2) males showed significant overlap with those caused by PTZ. Interestingly, microarray evidence also led to the identification of upregulated rRNA in F(2) males. Next, we generated microarray expression profiles of adult testis from F(0) and F(1) males. Further surprising, clustering of CNS and testis profiles and matching of differentially expressed genes in them provided evidence of a spermatogenic mechanism in the transgenerational effect observed. To our knowledge, we report for the first time detection of transgenerational spermatogenic inheritance of adult acquired somatic gene expression characteristic. The Drosophila systems model offers an excellent opportunity to understand the epigenetic mechanisms underlying the

Cytotoxic and antioxidant effect of chrysin on neonate mouse spermatogenic stem cells

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Mehran Pordel

2017-06-01

Full Text Available Background: So far, many plants have been used for the treatment of infertility. Several studies have revealed that chrysin (as an active metabolite improves animals' reproduction. Therefore, the objective of this study was to evaluate the effect of chrysin on Balb/C mice spermatogenic stem cells. Materials and Methods: In this in vitro experimental study Balb/C neonate spermatogonia stem cells cultured in DMEM-F12 medium were treated with various concentrations of chrysin (2.5, 5, 10, 20, 40 µg/ml for 6 and 12 days. Then the cytotoxicity was assessed using MTT, Akredin orange/Propodium Idid, DAPI and antioxidant concentration DCF-DA tests. Results: Chrysin showed no remarkable cytoxicity in concentrations less than 5 µg/ml. While, after 6 days the viability of cells treated with chrysin 10, 20 and 40 µg/ml was decreased to 30, 45 and 56 % (P<0.05 and P<0.001, respectiely; after 12 days the viability of cells was decreased to 44, 56 and 65 % (P<0.05, P<0.01 and P<0.001, respectiely. DCF-DA results revealed a 80 % antioxidant capacity of chrysin in 5 and 2.5µg/ml concentrations. Conclusion: Lower concentrations of chrysin has protective effect on Balb/C mice spermatogenic through improving cell viability, decreasing cells apoptosis and inhibiting free radicals.

Differential responses of neuronal and spermatogenic cells to the doppel cytotoxicity.

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Kefeng Qin

Full Text Available Although structurally and biochemically similar to the cellular prion (PrP(C, doppel (Dpl is unique in its biological functions. There are no reports about any neurodegenerative diseases induced by Dpl. However the artificial expression of Dpl in the PrP-deficient mouse brain causes ataxia with Purkinje cell death. Abundant Dpl proteins have been found in testis and depletion of the Dpl gene (Prnd causes male infertility. Therefore, we hypothesize different regulations of Prnd in the nerve and male productive systems. In this study, by electrophoretic mobility shift assays we have determined that two different sets of transcription factors are involved in regulation of the Prnd promoter in mouse neuronal N2a and GC-1 spermatogenic (spg cells, i.e., upstream stimulatory factors (USF in both cells, Brn-3 and Sp1 in GC-1 spg cells, and Sp3 in N2a cells, leading to the expression of Dpl in GC-1 spg but not in N2a cells. We have further defined that, in N2a cells, Dpl induces oxidative stress and apoptosis, which stimulate ataxia-telangiectasia mutated (ATM-modulating bindings of transcription factors, p53 and p21, to Prnp promoter, resulting the PrP(C elevation for counteraction of the Dpl cytotoxicity; in contrast, in GC-1 spg cells, phosphorylation of p21 and N-terminal truncated PrP may play roles in the control of Dpl-induced apoptosis, which may benefit the physiological function of Dpl in the male reproduction system.

Mucuna pruriens and its major constituent L-DOPA recover spermatogenic loss by combating ROS, loss of mitochondrial membrane potential and apoptosis.

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Singh, Akhand Pratap; Sarkar, Saumya; Tripathi, Muktanand; Rajender, Singh

2013-01-01

The Ayurvedic medicinal system claims Mucuna pruriens (MP) to possess pro-male fertility, aphrodisiac and adaptogenic properties. Some scientific evidence also supports its pro-male fertility properties; however, the mechanism of its action is not yet clear. The present study aimed at demonstrating spermatogenic restorative efficacy of MP and its major constituent L-DOPA (LD), and finding the possible mechanism of action thereof in a rat model. Ethinyl estradiol (EE) was administered at a rate of 3 mg/kg body weight (BW)/day for a period of 14 days to generate a rat model with compromised spermatogenesis. MP and LD were administered in two separate groups of these animals starting 15(th) day for a period of 56 days, and the results were compared with an auto-recovery (AR) group. Sperm count and motility, testis histo-architecture, level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis, peripheral hormone levels and testicular germ cell populations were analysed, in all experimental groups. We observed efficient and quick recovery of spermatogenesis in MP and LD groups in comparison to the auto-recovery group. The treatment regulated ROS level, apoptosis, and mitochondrial membrane potential (MMP), recovered the hypothalamic-pituitary-gonadal axis and the number of testicular germ cells, ultimately leading to increased sperm count and motility. M. pruriens efficiently recovers the spermatogenic loss induced due to EE administration. The recovery is mediated by reduction in ROS level, restoration of MMP, regulation of apoptosis and eventual increase in the number of germ cells and regulation of apoptosis. The present study simplified the complexity of mechanism involved and provided meaningful insights into MP/LD mediated correction of spermatogenic impairment caused by estrogens exposure. This is the first study demonstrating that L-DOPA largely accounts for pro-spermatogenic properties of M. pruriens. The manuscript bears CDRI

Development of an updated phytoestrogen database for use with the SWAN food frequency questionnaire: intakes and food sources in a community-based, multiethnic cohort study.

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Huang, Mei-Hua; Norris, Jean; Han, Weijuan; Block, Torin; Gold, Ellen; Crawford, Sybil; Greendale, Gail A

2012-01-01

Phytoestrogens, heterocyclic phenols found in plants, may benefit several health outcomes. However, epidemiologic studies of the health effects of dietary phytoestrogens have yielded mixed results, in part due to challenges inherent in estimating dietary intakes. The goal of this study was to improve the estimates of dietary phytoestrogen consumption using a modified Block Food Frequency Questionnaire (FFQ), a 137-item FFQ created for the Study of Women's Health Across the Nation (SWAN) in 1994. To expand the database of sources from which phytonutrient intakes were computed, we conducted a comprehensive PubMed/Medline search covering January 1994 through September 2008. The expanded database included 4 isoflavones, coumestrol, and 4 lignans. The new database estimated isoflavone content of 105 food items (76.6%) vs. 14 (10.2%) in the 1994 version and computed coumestrol content of 52 food items (38.0%), compared to 1 (0.7%) in the original version. Newly added were lignans; values for 104 FFQ food items (75.9%) were calculated. In addition, we report here the phytonutrient intakes for each racial and language group in the SWAN sample and present major food sources from which the phytonutrients came. This enhanced ascertainment of phytoestrogens will permit improved studies of their health effects.

[Effects of L-carnitine on the apoptosis of spermatogenic cells and epididymal sperm count and motility in rats with diabetes mellitus].

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Kang, Ning; Ma, Jie-hua; Zhou, Xin; Fan, Xiao-bo; Shang, Xue-jun; Huang, Yu-feng

2011-05-01

To explore the effects of L-carnitine (LC) on the apoptosis of spermatogenic cells and on the count and motility of epididymal sperm in rats with diabetes mellitus (DM). Twenty-four SD rats (200-230 g) were randomly divided into a control group, a DM model group and an LC group. After the establishment of DM models in the latter two groups by injection of streptozotocin (STZ) at 65 mg/kg, the controls and DM models were treated intragastrically with physiological saline, while the rats in the LC group with LC at 300 mg/kg, all for 6 consecutive weeks. Twenty-four hours after the last administration, all the rats were killed for the detection of the count and motility of epididymal sperm and the apoptosis of spermatogenic cells. The motilities of caput and cauda epididymal sperm were (53.7 +/- 1.8)% and (60.3 +/- 1.6)% in the LC group, significantly higher than in the DM model group ([32.2 +/- 2.0]% and [40.5 +/- 1.4]%, P count of cauda epididymal sperm was (25.5 +/- 1.1) x 10(6)/100 mg in the DM models, and was increased to (32.0 +/- 1.5) x 10(6)/100 mg after LC treatment (P sperm count, improved sperm motility, and reduced the apoptosis of spermatogenic cells in rats with DM.

Morphofunctional evaluation of the testis, duration of spermatogenesis and spermatogenic efficiency in the Japanese fancy mouse (Mus musculus molossinus).

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Costa, Guilherme M J; Leal, Marcelo C; França, Luiz R

2017-08-01

Japanese fancy mouse, mini mouse or pet mouse are common names used to refer to strains of mice that present with different colour varieties and coat types. Although many genetic studies that involve spotting phenotype based on the coat have been performed in these mice, there are no reports of quantitative data in the literature regarding testis structure and spermatogenic efficiency. Hence, in this study we researched testis function and spermatogenesis in the adult Japanese fancy mouse. The following values of 68 ± 6 mg and 0.94 ± 0.1% were obtained as mean testis weight and gonadosomatic index, respectively. In comparison with other investigated mice strains, the fancy mouse Leydig cell individual size was much smaller, resulting in higher numbers of these cells per gram of testis. As found for laboratory mice strains, as a result of the development of the acrosomic system, 12 stages of the seminiferous epithelium cycle have been described in this study. The combined frequencies of pre-meiotic and post-meiotic stages were respectively 24% and 64% and very similar to the laboratory mice. The more differentiated germ cell types marked at 1 h or 9 days after tritiated thymidine administration were preleptotene/leptotene and pachytene spermatocytes at the same stage (VIII). The mean duration of one spermatogenic cycle was 8.8 ± 0.01 days and the total length of spermatogenesis lasted 37.8 ± 0.01 days (4.5 cycles). A high number of germ cell apoptosis was evident during meiosis, resulting in lower Sertoli cell and spermatogenic efficiencies, when compared with laboratory mice strains.

Association between dietary phytoestrogens intakes and prostate cancer risk in Sicily.

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Russo, Giorgio I; Di Mauro, Marina; Regis, Federica; Reale, Giulio; Campisi, Daniele; Marranzano, Marina; Lo Giudice, Arturo; Solinas, Tatiana; Madonia, Massimo; Cimino, Sebastiano; Morgia, Giuseppe

2018-03-01

In this study we aimed to investigate the association between dietary phytoestrogen consumption and prostate cancer in a sample of southern Italian individuals. A population-based case-control study on the association between prostate cancer and dietary factors was conducted from January 2015 to December 2016 in a single institution of the municipality of Catania, southern Italy (Registration number: 41/2015). A total of 118 histopathological-verified prostate cancer (PCa) cases and a total of 222 controls were collected. Dietary data was collected by using two food frequency questionnaires. Patients with PCa consumed significantly higher levels of phytoestrogens. Multivariate logistic regression showed that lignans (Q[quartile]4 vs. Q1, OR [odds ratio] = 4.72; p < .05) and specifically, lariciresinol (Q4 vs. Q1, OR = 4.60; p < .05), pinoresinol (Q4 vs. Q1, OR = 5.62; p < .05), matairesinol (Q4 vs. Q1, OR = 3.63; p < .05), secoisolariciresinol (Q4 vs. Q1, OR = 4.10; p < .05) were associated with increased risk of PCa. Furthermore, we found that isoflavones (Q3 vs. Q1, OR = 0.28; p < .05) and specifically, genistein (Q4 vs. Q1, OR = 0.40; p < .05) were associated with reduced risk of PCa. We found of an inverse association between dietary isoflavone intake and PCa, while a positive association was found with lignans intake.

Mucuna pruriens and its major constituent L-DOPA recover spermatogenic loss by combating ROS, loss of mitochondrial membrane potential and apoptosis.

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Akhand Pratap Singh

Full Text Available BACKGROUND: The Ayurvedic medicinal system claims Mucuna pruriens (MP to possess pro-male fertility, aphrodisiac and adaptogenic properties. Some scientific evidence also supports its pro-male fertility properties; however, the mechanism of its action is not yet clear. The present study aimed at demonstrating spermatogenic restorative efficacy of MP and its major constituent L-DOPA (LD, and finding the possible mechanism of action thereof in a rat model. METHODOLOGY/FINDINGS: Ethinyl estradiol (EE was administered at a rate of 3 mg/kg body weight (BW/day for a period of 14 days to generate a rat model with compromised spermatogenesis. MP and LD were administered in two separate groups of these animals starting 15(th day for a period of 56 days, and the results were compared with an auto-recovery (AR group. Sperm count and motility, testis histo-architecture, level of reactive oxygen species (ROS, mitochondrial membrane potential (MMP, apoptosis, peripheral hormone levels and testicular germ cell populations were analysed, in all experimental groups. We observed efficient and quick recovery of spermatogenesis in MP and LD groups in comparison to the auto-recovery group. The treatment regulated ROS level, apoptosis, and mitochondrial membrane potential (MMP, recovered the hypothalamic-pituitary-gonadal axis and the number of testicular germ cells, ultimately leading to increased sperm count and motility. CONCLUSION/SIGNIFICANCE: M. pruriens efficiently recovers the spermatogenic loss induced due to EE administration. The recovery is mediated by reduction in ROS level, restoration of MMP, regulation of apoptosis and eventual increase in the number of germ cells and regulation of apoptosis. The present study simplified the complexity of mechanism involved and provided meaningful insights into MP/LD mediated correction of spermatogenic impairment caused by estrogens exposure. This is the first study demonstrating that L-DOPA largely accounts for pro-spermatogenic

Temperature dependence of intracellular Ca2+ homeostasis in rat meiotic and postmeiotic spermatogenic cells.

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Herrera, E; Salas, K; Lagos, N; Benos, D J; Reyes, J G

2001-10-01

The hypothesis that intracellular [Ca2+] is a cell parameter responsive to extreme temperatures in rat meiotic and postmeiotic spermatogenic cells was tested using intracellular fluorescent probes for Ca2+ and pH. In agreement with this hypothesis, extreme temperatures induced a rapid increase of cytosolic [Ca2+] in rat pachytene spermatocytes and round spermatids. Oscillatory changes in temperature can induce oscillations in cytosolic [Ca2+] in these cells. Intracellular [Ca2+] homeostasis in round spermatids was more sensitive to high temperatures compared with pachytene spermatocytes. The calculated activation energies for SERCA ATPase-mediated fluxes in pachytene spermatocytes and round spermatids were 62 and 75 kJ mol(-1), respectively. The activation energies for leak fluxes from intracellular Ca2+ stores were 55 and 68 kJ mol(-1) for pachytene spermatocytes and round spermatids, respectively. Together with changes in cytosolic [Ca2+], round spermatids undergo a decrease in pH(i) at high temperatures. This temperature-induced decrease in pH(i) appears to be partially responsible for the increase in cytosolic [Ca2+] of round spermatids induced by high temperatures. This characteristic of rat meiotic and postmeiotic spermatogenic cells to undergo an increment in cytosolic Ca2+ at temperatures > 33 degrees C can be related to the induction of programmed cell death by high temperatures in these cells.

Rapid effects of phytoestrogens on human colonic smooth muscle are mediated by oestrogen receptor beta.

LENUS (Irish Health Repository)

Hogan, A M

2012-02-01

Epidemiological studies have correlated consumption of dietary phytoestrogens with beneficial effects on colon, breast and prostate cancers. Genomic and non-genomic mechanisms are responsible for anti-carcinogenic effects but, until now, the effect on human colon was assumed to be passive and remote. No direct effect on human colonic smooth muscle has previously been described. Institutional research board approval was granted. Histologically normal colon was obtained from the proximal resection margin of colorectal carcinoma specimens. Circular smooth muscle strips were microdissected and suspended under 1g of tension in organ baths containing oxygenated Krebs solution at 37 degrees C. After an equilibration period, tissues were exposed to diarylpropionitrile (DPN) (ER beta agonist) and 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT) (ER alpha agonist) or to the synthetic phytoestrogen compounds genistein (n=8), daidzein (n=8), fisetin (n=8) and quercetin (n=8) in the presence or absence of fulvestrant (oestrogen receptor antagonist). Mechanism of action was investigated by inhibition of downstream pathways. The cholinergic agonist carbachol was used to induce contractile activity. Tension was recorded isometrically. Phytoestrogens inhibit carbachol-induced colonic contractility. In keeping with a non-genomic, rapid onset direct action, the effect was within minutes, reversible and similar to previously described actions of 17 beta oestradiol. No effect was seen in the presence of fulvestrant indicating receptor modulation. While the DPN exerted inhibitory effects, PPT did not. The effect appears to be reliant on a p38\\/mitogen activated protein kinase mediated induction of nitric oxide production in colonic smooth muscle. The present data set provides the first description of a direct effect of genistein, daidzein, fisetin and quercetin on human colonic smooth muscle. The presence of ER in colonic smooth muscle has been functionally proven and the beta

Estrogenic effects of phytoestrogens in brown trout (Salmo trutta)

DEFF Research Database (Denmark)

Nielsen, Louise Marie; Holbech, Henrik; Bjerregaard, Poul

2010-01-01

, the potential effect of the waterborne phytoestrogens on endemic fish species is largely unknown. In the present investigation, the estrogenic effect of biochanin A was tested in brown trout through water exposure experiments. Juvenile brown trout of both sexes were exposed to different concentrations...... of biochanin A. In a ten day exposure experiments, NOEC and LOEC for plasma vitellogenin induction in brown trout were found to be 0.8µg biochanin A/L and 1.2µg biochanin A/L, respectively. A six hour pulse experiment resulted in NOEC and LOEC for induction of plasma vitellogenin in brown trout of 48µg...... biochanin A/L and 186µg biochanin A/L, respectively. Investigations of the ability of genistein to induce vitellogenin synthesis in brown trout are ongoing....

Multiclass analytical method for the determination of natural/synthetic steroid hormones, phytoestrogens, and mycoestrogens in milk and yogurt.

Science.gov (United States)

Socas-Rodríguez, Bárbara; Lanková, Darina; Urbancová, Kateřina; Krtková, Veronika; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel; Pulkrabová, Jana; Hajšlová, Jana

2017-07-01

Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 μg/L (0.2-6.0 μg/kg dry weight) and 0.02-0.90 μg/kg (0.2-6.0 μg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 μg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens.

Effect of Black maca (Lepidium meyenii) on one spermatogenic cycle in rats.

Science.gov (United States)

Gonzales, G F; Nieto, J; Rubio, J; Gasco, M

2006-10-01

Lepidium meyenii (Maca) grows exclusively between 4000 and 4500 m above sea level in the Peruvian central Andes. The hypocotyls of this plant are traditionally used in the Andean region for their supposed fertility-enhancing properties. The hypocotyls have different colours. Of these, Black maca has better effects on spermatogenesis. The present study aimed to test the hypothesis that Black maca has early effects during a spermatogenic cycle (12 days) of male rats. For this, testicular spermatid, epididymal sperm and vas deferens sperm counts were measured after 1, 3, 5, 7 and 12 days of treatment with Black maca. Aqueous extract of Black maca was given orally by daily gavage at a dose of 2 g kg(-1). In a spermatogenic cycle, compared with day 1, daily sperm production (DSP) was lower at day 7 (control), whereas with Black maca, the difference was observed at day 12. Epididymal sperm count was higher in rats treated with Black maca at days 1, 3 and 7, but similar to controls at days 5 and 12; similarly sperm counts in vas deferens was higher in rats treated with Black maca in days 3, 5 and 7, but similar to controls at days 1 and 12. From this, it is suggested that first action of Black maca was at epididymal level increasing sperm count after 1 day of treatment, whereas an increase in sperm count was observed in vas deferens at day 3 of treatment. Finally, an increase in DSP was observed after 7 days of treatment with Black maca. Testicular testosterone was not affected after 7 days treatment with Black maca. In conclusion, Black maca affects sperm count as early as 1 day after beginning of treatment.

Soy and other legumes: 'Bean' around a long time but are they the 'superfoods' of the millennium and what are the safety issues for their constituent phytoestrogens?

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Setchell, K D; Radd, S

2000-09-01

The recognition that legumes and, in particular, soybeans provide not only an excellent source of vegetable protein but also contain appreciable amounts of a number of phytoprotectants has increased general awareness of their potential nutritional and health properties. Since the discovery that soybeans are one of the richest dietary sources of bioavailable phytoestrogens, this legume has been elevated to the forefront of clinical nutritional research. These natural 'selective oestrogen receptor modulators' have been shown to be bioactive. The recent approval by the Food and Drug Administration in the United States for a health claim for soy protein reducing risk for heart disease by its effects on lowering cholesterol levels has led to the increased awareness of the health benefits of soy protein. However, the presence of high levels of phytoestrogens in soybeans has also led to concerns over the potential safety of soy foods. This review will focus on the cardioprotective benefits of legumes and discuss the hypothetical concerns regarding the constituent phytoestrogens.

Model of personalised risk assessment of phytoestrogen intake based on 11 SNP in ESR1 and ESR2 genes

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Radoslav Zidek

2016-12-01

Full Text Available Phytoestrogens can induce biological responses in vertebrates by mimicking or modulating the action or production of endogenous hormones, and because of their structural similarity with estradiol they have the ability to cause estrogenic or anti-estrogenic effects. Risk assessment of phytoestrogens intake may therefore provide important information useful in the adjustment of nutrients composition, as one of nutrigenomics approaches. Proper risk assessment is an essential part of good nutrient composition. The current risk assessment procedures does use an additive effect of genes, but the accumulation of relevant factors do not count with the distribution of risk in the European population. A combination of approaches based on genetic score, along with the use of the data bases like 1000 genomes and dbSNP is a powerful tool for population risk modelling that would provide reasonable results without needs of as testing a representative number of individual genetic profiles.

Adaptive response of spermatogenic cell apoptosis selectively induced by low dose X-ray irradiation in mice

International Nuclear Information System (INIS)

Liu Guangwei; Dong Lihua; Liu Yang; Lv Zhe; Liu Shuchun; Gong Shouliang

2003-01-01

Objective: The adaptive response of spermatogenic cell apoptosis induced by whole-body X-ray irradiation at low doses was studied in mice. Methods: Kunming male mice were irradiated with an inductive dose (D1:75 mGy) and/or a challenging dose (D2:1.0, 2.0 or 3.0 Gy). Different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptotic percentages were analysed using flow cytometry (FCM). Results: When the mice were irradiated with D1 6 h before irradiation with D2, the apoptotic percentages of the spermatogonia and spermatocytes declined rapidly as compared with those in the groups irradiated with D2 only, and those of spermatids and spermatozoa showed no significant changes. When the interval times between D1 and D2 was 3, 6, 12 or 24 h, the apoptotic percentages in spermatogonia and spermatocytes reduced early, significantly and continued for a longer duration after smaller D2(1.0 and 2.0 Gy) irradiation, while the apoptotic percentages did not change after larger D2(3.0 Gy) irradiation. Conclusion: The adaptive response of apoptosis in spermatogonia and spermatocytes could be selectively induced by low dose X-ray irradiation. The adaptive response could be closely related to the D2 dose and interval time between D1 and D2

Changes of mitochondrial structure, ATPase and Ca2+ concentration in spermatogenic cells of mouse testes induced by low dose radiation

International Nuclear Information System (INIS)

Wang Zhicheng; Liu Shuchun; Li Pengwu; Kang Shunai; Liang Shuo; Zhao Gang; Gong Shouliang

2009-01-01

Objective: To observe the ultrastructure, ATPase activity and Ca 2+ concentration ([Ca 2+ ]i) of mitochondria in the sperematogenic cells of mouse testes 3-24 h after low dose radiation with 0.025-0.200 Gy X-rays, and illuminate the effects of mitochondrion structure and relative biological function on apoptosis. Methods: The ultrastructure changes of mitochondria in the spermatogenic cells were observed with transmission electron microscope; the ATPase activity was measured with protein enzymic method; [Ca 2+ ]i was measured indirectly by flow cytometry with Fluo-3 probes. Results: The mitochondria swelled and vacuolizated, and their cristae were broken in the spermatogonia and spermatocytes 12 h after irradiation, and their nuclei were karyopyknosis, the acrosomal vesicle structure was ambiguity, the membrane structure was unclear, and the mitochondria in spermatids were vacuolization. The activities of Na + -K + -ATPase in mouse testis tissue 12 h after irradiated with 0.025-0.200 Gy decreased compared with those with 0 Gy, the Na + -K + -ATPase activities of the cells irradiated with 0.05-0.200 Gy decreased significantly compared with those with 0 Gy (P 2+ -ATPase of the cells irradiated with 0.025-0.200 Gy decreased significantly compared with those with 0 Gy (P 2+ ]i in mouse testis spermatogenic cells had similar dose-response relationship, [Ca 2+ ]i after irradiated with 0.075 Gy decreased compared with those with 0 Gy (P + -K + -ATPase in mouse testis tissues decreased obviously compared with those at 0 h (P 2+ -ATPase in mouse testis tissues increased slightly at 3 h, then decreased at 6-24 h compared with those at 0 h (P 2+ ]i in mouse testis spermatogenic cells had similar time course-response relationship, [Ca 2+ ]i at 12 h decreased significantly compared with at 0 h (P 2+ ]i induced by low dose radiation. (authors)

Effects of phytoestrogen supplementation in postmenopausal women with dry eye syndrome: a randomized clinical trial.

Science.gov (United States)

Scuderi, Gianluca; Contestabile, Maria Teresa; Gagliano, Caterina; Iacovello, Daniela; Scuderi, Luca; Avitabile, Teresio

2012-12-01

To evaluate the correlation between tear osmolarity and blood levels of 17-β estradiol, estrone, and testosterone in postmenopausal women with dry eye syndrome, and to assess the efficacy and safety of oral supplementation with phytoestrogens, lipoic acid, and eicosapentaenoic acid in this population. Cross-sectional study including 66 postmenopausal women with dry eye syndrome. Sixty-six postmenopausal women with dry eye syndrome were enrolled in a randomized, double-blind, placebo-controlled, crossover study. Patients were divided into 2 groups (groups A and B) and treated, respectively, with phytoestrogen (Bioos, Montegiorgio, Italy) tablets or placebo tablets for 30 days. The 2 treatment periods were separated by a 30-day washout. Patients were examined on days 0 and 30 of each period. Assessments included blood levels of sex hormones, the Schirmer test for tear production, and measurement of tear osmolarity and tear film break-up time. At baseline, all patients had low sex hormone levels, which were correlated with high tear film osmolarity values (r = -0.59,-0.61,-0.58, respectively). After 30 days of therapy, the group treated with Lacrisek® (Bioos) had significantly decreased tear osmolarity (Pdry eye syndrome in postmenopausal women. Copyright © 2012 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Influence of partial replacement of soya bean meal by faba beans or peas in heavy pigs diet on meat quality, residual anti-nutritional factors and phytoestrogen content.

Science.gov (United States)

Gatta, Domenico; Russo, Claudia; Giuliotti, Lorella; Mannari, Claudio; Picciarelli, Piero; Lombardi, Lara; Giovannini, Luca; Ceccarelli, Nello; Mariotti, Lorenzo

2013-06-01

The study evaluated the partial substitution of soybean meal by faba beans (18%) or peas (20%) as additional protein sources in diets destined for typical Italian heavy pig production. It compared animal performances, meat quality, the presence of residual anti-nutritional factors (ANF) and phytoestrogens in plasma and meat and the possible effects on pig health, by evaluating oxidative, inflammatory and pro-atherogenic markers. The results showed that the productive performances, expressed as body weight and feed conversion ratio, of pigs fed with faba bean and pea diets were similar to those of pigs fed only the soybean meal. Meat quality of pigs fed with the three diets was similar in colour, water-holding capacity, tenderness and chemical composition. Despite the higher levels of phytoestrogen in the plasma of pigs fed only the soybean meal, phytoestrogen concentration in the muscle was equivalent to that of animals fed diets with faba beans, whereas pigs fed a diet with peas showed a lower concentration. Inflammation and pro-atherogenic parameters did not show significant differences among the three diets. Overall, the partial substitution of soybean meal by faba beans appears more interesting than with peas, particularly in relation to the higher amount of polyphenols in the diet and the highest concentration of phytoestrogens found in the plasma and muscle of animals, while the pyrimidine anti-nutritional compounds present in the diet did not appear to accumulate and had no effect on the growth performance of animals.

Molecular cloning of a novel nuclear factor, TDRP1, in spermatogenic cells of testis and its relationship with spermatogenesis

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Wang, Xuanchun [Department of Endocrinology, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Jiang, Haowen [Department of Urology, Huashan Hospital, Institute of Urology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Zhou, Wenbai; Zhang, Zhaoyun; Yang, Zhihong [Department of Endocrinology, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Lu, Yong [Department of Urology, Huashan Hospital, Institute of Urology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Lu, Bin [Department of Endocrinology, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Wang, Xiang [Department of Urology, Huashan Hospital, Institute of Urology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Ding, Qiang, E-mail: dingqiangd@hotmail.com [Department of Urology, Huashan Hospital, Institute of Urology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China); Hu, Renming, E-mail: renminghu@fudan.edu.cn [Department of Endocrinology, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical College, Fudan University, Shanghai 200040 (China)

2010-03-26

We reported the identification of a novel gene termed TDRP (encoding testis development-related protein) that might be involved in spermatogenesis. The human TDRP gene had two distinct transcripts, TDRP1 and TDRP2, which encoded proteins of 183 aa and 198 aa respectively. Tdrp mRNA was predominantly expressed in testis tissue. We generated rabbit polyclonal antibodies specific against human TDRP1. Immunohistochemistry analysis showed TDRP1 was expressed in spermatogenic cells, especially with high expression in spermatocytes. We provided evidence that TDRP1 distributed in both cytoplasm and nuclei of spermatogenic cells. Expression patterns of Tdrp1 mRNA and its protein were investigated in the rat testis tissues of different developmental stages. Both Tdrp1 mRNA and its protein were barely detected in the testis of neonatal rats, increased remarkably at 3 weeks postpartum, and peaked at 2 months postpartum. We also investigated TDRP1 expressions in testis tissues of azoospermic men with defective spermatogenesis. Western blot analysis showed that TDRP1 expressions were significantly lower in the testis tissues of azoospermic men compared with normal controls. These current data demonstrated that as a nuclear factor, TDRP1 might play an important role in spermatogenesis.

Molecular cloning of a novel nuclear factor, TDRP1, in spermatogenic cells of testis and its relationship with spermatogenesis

International Nuclear Information System (INIS)

Wang, Xuanchun; Jiang, Haowen; Zhou, Wenbai; Zhang, Zhaoyun; Yang, Zhihong; Lu, Yong; Lu, Bin; Wang, Xiang; Ding, Qiang; Hu, Renming

2010-01-01

We reported the identification of a novel gene termed TDRP (encoding testis development-related protein) that might be involved in spermatogenesis. The human TDRP gene had two distinct transcripts, TDRP1 and TDRP2, which encoded proteins of 183 aa and 198 aa respectively. Tdrp mRNA was predominantly expressed in testis tissue. We generated rabbit polyclonal antibodies specific against human TDRP1. Immunohistochemistry analysis showed TDRP1 was expressed in spermatogenic cells, especially with high expression in spermatocytes. We provided evidence that TDRP1 distributed in both cytoplasm and nuclei of spermatogenic cells. Expression patterns of Tdrp1 mRNA and its protein were investigated in the rat testis tissues of different developmental stages. Both Tdrp1 mRNA and its protein were barely detected in the testis of neonatal rats, increased remarkably at 3 weeks postpartum, and peaked at 2 months postpartum. We also investigated TDRP1 expressions in testis tissues of azoospermic men with defective spermatogenesis. Western blot analysis showed that TDRP1 expressions were significantly lower in the testis tissues of azoospermic men compared with normal controls. These current data demonstrated that as a nuclear factor, TDRP1 might play an important role in spermatogenesis.

Recovery of microtubules on the blepharoplast of Ceratopteris spermatogenous cells after oryzalin treatment.

Science.gov (United States)

Vaughn, Kevin C; Bowling, Andrew J

2008-11-01

Most land plants have ill-defined microtubule-organizing centers (MTOCs), consisting of sites on the nuclear envelope or even along microtubules (MTs). In contrast, the spermatogenous cells of the pteridophyte Ceratopteris richardii have a well-defined MTOC, the blepharoplast, which organizes MTs through the last two division cycles. This allows a rare opportunity to study the organization and workings of a structurally well-defined plant MTOC. In this study, antheridial plants were treated with levels of oryzalin that cause complete MT loss from the cells containing blepharoplasts. The oryzalin was then washed out and plants were allowed to recover for varying amounts of time. If the spermatogenous cells were fixed prior to washing out, the blepharoplasts had an unusual appearance. In the matrix (pericentriolar) material where MT ends are normally found, clear areas of about the diameter of MTs were seen embedded in a much deeper matrix, made more obvious in stereo pairs. Occasionally, the matrix material was highly distended, although the basal body template cylinder morphology appeared to be unaltered. The blepharoplasts often occurred as clusters of 2 or 4, indicating that blepharoplast reproduction is not affected by the lack of MTs, but that their movement to the poles is. Gamma (gamma) tubulin antibodies labeled the edge of the blepharoplast in areas where the pits are located, indicating that these might be sites for MT nucleation. After wash out, the new MTs always re-appeared on the blepharoplast and the recovery occurred within an hour of washout. MT lengths increased with increasing washout time and were indistinguishable from untreated blepharoplasts after 24 h of recovery. After washout, arrays formed in new sperm cells such as the spline and basal bodies were often malformed or present in multiple copies, as were the blepharoplasts in these cells prior to wash out. These data indicate that the blepharoplast serves as the site of MT nucleation and

Ouabain interactions with the α4 isoform of the sodium pump trigger non-classical steroid hormone signaling and integrin expression in spermatogenic cells.

Science.gov (United States)

Upmanyu, Neha; Dietze, Raimund; Kirch, Ulrike; Scheiner-Bobis, Georgios

2016-11-01

In addition to the ubiquitous α1 isoform of the sodium pump, sperm cells also express a male-specific α4 isoform whose function has been associated with sperm motility, fertility, and capacitation. Here we investigate in the murine spermatogenic cell line GC-2 interactions of the α4 isoform with the cardiotonic steroid ouabain in signaling cascades involved in the non-classical action of steroid hormones. Exposure of GC-2 cells to low concentrations of ouabain stimulates the phosphorylation of Erk1/2 and of the transcription factors CREB and ATF-1. As a consequence of this signaling cascade, ouabain stimulates on the mRNA level the expression of integrins αv, β3 and α5, whose expression is also modulated by the cAMP response element. Increased expression of integrins αv and β3 is also seen in cultures of seminiferous tubules exposed to 10nM ouabain. At the protein level we observed a significant stimulation of β3 integrin expression by ouabain. Abrogation of α4 isoform expression by siRNA leads to the complete suppression of all ouabain-induced signaling mentioned above, including its stimulatory effect on the expression of β3 integrin. The results presented here demonstrate for the first time the induction of signaling cascades through the interaction of ouabain with the α4 isoform in a germ-cell derived cell line. The novel finding that these interactions lead to increased expression of integrins in GC-2 cells and the confirmation of these results in the ex vivo experiments indicate that hormone/receptor-like interactions of ouabain with the α4 isoform might be of significance for male physiology. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Trifolium alexandrinum phytoestrogens on oestrous behaviour, ovarian activity and reproductive performance of ewes during the non-breeding season.

Science.gov (United States)

Hashem, N M; El-Azrak, K M; Nour El-Din, A N M; Sallam, S M; Taha, T A; Salem, M H

2018-03-08

Phytoestrogens are classified as naturally occurring endocrine disrupting chemicals that may affect reproductive performance of farm animals. To investigate the effects of Berseem clover phytoestrogens on reproductive performance of seasonal anoestrus ewes, twenty four late pregnant Rahmani ewes were fed either Berseem clover or maize silage (n = 12/treatment). Treatment started 2 months prepartum and continued until oestrous induction (week 8 postpartum), using the CIDR-eCG based protocol, and early pregnancy. Throughout the 2-8 weeks postpartum, oestrous rate and ovarian activity were not affected by treatment. After oestrous induction, ewes in both groups expressed comparable oestrous rates; however feeding Berseem clover extended (P ewes fed maize silage than for those fed Berseem clover. Fecundity and litter size tended to be greater (about 35%; P = 0.132 and 0.085, respectively) in the maize silage fed ewes. In conclusion, feeding Berseem clover throughout seasonal anoestrus disrupted aspects of behavioural oestrus and there was less luteal P 4 synthesis and fecundity of ewes. Copyright © 2018 Elsevier B.V. All rights reserved.

Role of O6-alkylguanine-DNA alkyltransferase in the resistance of mouse spermatogenic cells to O6-alkylating agents.

Science.gov (United States)

Thompson, M J; Abdul-Rahman, S; Baker, T G; Rafferty, J A; Margison, G P; Bibby, M C

2000-07-01

The O(6)-alkylguanine-DNA alkyltransferase inactivator O(6)-benzylguanine was administered to BALB/c mice either alone or before exposure to 1,3-bis(2-chloroethyl)-1-nitrosourea to study the role of the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase in the protection of the testis against anti-cancer O(6)-alkylating agents. Exposure of the mice to 1, 3-bis(2-chloroethyl)-1-nitrosourea or O(6)-benzylguanine alone did not produce any marked testicular toxicity at the times studied. Testicular O(6)-alkylguanine-DNA alkyltransferase concentrations were assayed between 0 and 240 min after O(6)-benzylguanine treatment and were shown to be > 95% depleted 15 min after treatment with O(6)-benzylguanine and remained at > 95% at all the times assayed. Histological examination, the reduction in testicular mass and the induction of spermatogenic cell apoptosis showed that this depletion significantly potentiated 1, 3-bis(2-chloroethyl)-1-nitrosourea-induced testicular damage after treatment. Major histological damage was apparent 42 days after treatment, demonstrating that the stem spermatogonia were significantly affected by the combination. These results demonstrate that O(6)-alkylguanine-DNA alkyltransferase plays a significant role in protecting the spermatogenic cells from damage caused by DNA alkylation and indicate that the observed toxicity may result from damage to stem spermatogonia.

High-purity flow sorting of early meiocytes based on DNA analysis of guinea pig spermatogenic cells.

Science.gov (United States)

Rodríguez-Casuriaga, Rosana; Geisinger, Adriana; Santiñaque, Federico F; López-Carro, Beatriz; Folle, Gustavo A

2011-08-01

Mammalian spermatogenesis is still nowadays poorly understood at the molecular level. Testis cellular heterogeneity is a major drawback for spermatogenic gene expression studies, especially when research is focused on stages that are usually very short and poorly represented at the cellular level such as initial meiotic prophase I (i.e., leptotene [L] and zygotene [Z]). Presumably, genes whose products are involved in critical meiotic events such as alignment, pairing and recombination of homologous chromosomes are expressed during the short stages of early meiotic prophase. Aiming to characterize mammalian early meiotic gene expression, we have found the guinea pig (Cavia porcellus) as an especially attractive model. A detailed analysis of its first spermatogenic wave by flow cytometry (FCM) and optical microscopy showed that guinea pig testes exhibit a higher representation of early meiotic stages compared to other studied rodents, partly because of their longer span, and also as a result of the increased number of cells entering meiosis. Moreover, we have found that adult guinea pig testes exhibit a peculiar 4C DNA content profile, with a bimodal peak for L/Z and P spermatocytes that is absent in other rodents. Besides, we show that this unusual 4C peak allows the separation by FCM of highly pure L/Z spermatocyte populations aside from pachytene ones, even from adult individuals. To our knowledge, this is the first report on an accurate and suitable method for highly pure early meiotic prophase cell isolation from adult mammals, and thus sets an interesting approach for gene expression studies aiming at a deeper understanding of the molecular groundwork underlying male gamete production. Copyright © 2011 International Society for Advancement of Cytometry.

BAX and tumor suppressor TRP53 are important in regulating mutagenesis in spermatogenic cells in mice.

Science.gov (United States)

Xu, Guogang; Vogel, Kristine S; McMahan, C Alex; Herbert, Damon C; Walter, Christi A

2010-12-01

During the first wave of spermatogenesis, and in response to ionizing radiation, elevated mutant frequencies are reduced to a low level by unidentified mechanisms. Apoptosis is occurring in the same time frame that the mutant frequency declines. We examined the role of apoptosis in regulating mutant frequency during spermatogenesis. Apoptosis and mutant frequencies were determined in spermatogenic cells obtained from Bax-null or Trp53-null mice. The results showed that spermatogenic lineage apoptosis was markedly decreased in Bax-null mice and was accompanied by a significantly increased spontaneous mutant frequency in seminiferous tubule cells compared to that of wild-type mice. Apoptosis profiles in the seminiferous tubules for Trp53-null were similar to control mice. Spontaneous mutant frequencies in pachytene spermatocytes and in round spermatids from Trp53-null mice were not significantly different from those of wild-type mice. However, epididymal spermatozoa from Trp53-null mice displayed a greater spontaneous mutant frequency compared to that from wild-type mice. A greater proportion of spontaneous transversions and a greater proportion of insertions/deletions 15 days after ionizing radiation were observed in Trp53-null mice compared to wild-type mice. Base excision repair activity in mixed germ cell nuclear extracts prepared from Trp53-null mice was significantly lower than that for wild-type controls. These data indicate that BAX-mediated apoptosis plays a significant role in regulating spontaneous mutagenesis in seminiferous tubule cells obtained from neonatal mice, whereas tumor suppressor TRP53 plays a significant role in regulating spontaneous mutagenesis between postmeiotic round spermatid and epididymal spermatozoon stages of spermiogenesis.

Behavioral and spermatogenic hybrid male breakdown in Nasonia.

Science.gov (United States)

Clark, M E; O'Hara, F P; Chawla, A; Werren, J H

2010-03-01

Several reproductive barriers exist within the Nasonia species complex, including allopatry, premating behavioral isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioral sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviors, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared with wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviorally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than nonfunctional sperm, is different from most described cases of hybrid male sterility, and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioral sterility, and indicate that Wolbachia-induced hybrid incompatibility has arisen early in species divergence, relative to behavioral sterility and spermatogenic infertility.

Behavioural and spermatogenic hybrid male breakdown in Nasonia

Science.gov (United States)

Clark, Michael E.; O’Hara, F. Patrick; Chawla, Ankur; Werren, John H.

2010-01-01

Several reproductive barriers exists within the Nasonia species complex, including allopatry, premating behavioural isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioural sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviours, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared to wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviourally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than non-functional sperm, is different from most described cases of hybrid male sterility and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioural sterility, and indicated that Wolbachia induced hybrid incompatibility has arisen early in species divergence, relative to behavioural sterility and spermatogenic infertility. PMID:20087395

Quantitative proteomics and transcriptomics addressing the estrogen receptor subtype-mediated effects in T47D breast cancer cells exposed to the phytoestrogen genistein

NARCIS (Netherlands)

Sotoca Covaleda, A.M.; Sollewijn Gelpke, M.D.; Boeren, S.; Ström, A.; Gustafsson, J.A.; Murk, A.J.; Rietjens, I.M.C.M.; Vervoort, J.J.M.

2011-01-01

The present study addresses, by transcriptomics and quantitative SILAC-based proteomics, the estrogen receptor alpha (ER) and beta (ERß)-mediated effects on gene and protein expression in T47D breast cancer cells exposed to the phytoestrogen genistein. Using the T47D human breast cancer cell line

New animal model for the study of postmenopausal coronary and cerebral artery function: the Watanabe heritable hyperlipidemic rabbit fed on a diet avoiding phytoestrogens

DEFF Research Database (Denmark)

Dalsgaard, T; Larsen, C R; Mortensen, A

2002-01-01

to treatment for 16 weeks with either 17 beta-estradiol or placebo. The chow used was semi-synthetic, thereby avoiding the influence of phytoestrogens. Ring segments of cerebral and coronary arteries were mounted for isometric tension recordings in myographs. The passive and active length-tension relationships...

The Improvement of Hypertension by Probiotics: Effects on Cholesterol, Diabetes, Renin, and Phytoestrogens

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Huey-Shi Lye

2009-08-01

Full Text Available Probiotics are live organisms that are primarily used to improve gastrointestinal disorders such as diarrhea, irritable bowel syndrome, constipation, lactose intolerance, and to inhibit the excessive proliferation of pathogenic intestinal bacteria. However, recent studies have suggested that probiotics could have beneficial effects beyond gastrointestinal health, as they were found to improve certain metabolic disorders such as hypertension. Hypertension is caused by various factors and the predominant causes include an increase in cholesterol levels, incidence of diabetes, inconsistent modulation of renin and imbalanced sexual hormones. This review discusses the antihypertensive roles of probiotics via the improvement and/or treatment of lipid profiles, modulation of insulin resistance and sensitivity, the modulation of renin levels and also the conversion of bioactive phytoestrogens as an alternative replacement of sexual hormones such as estrogen and progesterone.

Up-regulation of interleukin-4 production via NF-AT/AP-1 activation in T cells by biochanin A, a phytoestrogen and its metabolites

International Nuclear Information System (INIS)

Park, Jin; Chung, Su Wol; Kim, Seung Hyun; Kim, Tae Sung

2006-01-01

Phytoestrogens are naturally occurring compounds derived from plants. Although phytoestrogens exhibit many biological functions including estrogen agonist/antagonist properties, the effect on allergic responses remains unclear. In this study, we investigated whether biochanin A, a phytoestrogen and its metabolites, genistein, p-ethylphenol and phenolic acid, affect production of IL-4, a pro-inflammatory cytokine closely associated with allergic immune responses, in primary CD4 + T cells and EL4 T lymphoma cells. Biochanin A, genistein and p-ethylphenol significantly enhanced IL-4 production from both CD4 + T cells and EL4 cells in a dose-dependent manner, while phenolic acid did not. Biochanin A, genistein and p-ethylphenol also enhanced IL-4 gene promoter activity in EL4 cells transiently transfected with IL-4 promoter constructs, but this effect was impaired in EL4 cells transfected with an IL-4 promoter construct deleted of a P4 site carrying NF-AT and AP-1 binding sites. In addition, biochanin A, genistein and p-ethylphenol increased both NF-AT and AP-1 DNA binding activities, indicating that they might enhance IL-4 production via NF-AT/AP-1 activation. Furthermore, biochanin A, genistein and p-ethylphenol increased p38 MAPK phosphorylation and PKC activity, while they did not affect ERK phosphorylation. The enhanced NF-AT DNA binding activities were suppressed by inhibitors for PI3-K and PKC, but not by p38 MAPK inhibitors. In contrast, the enhanced AP-1 DNA binding activities and p38 MAPK phosphorylation were significantly suppressed by specific inhibitors for PKC and p38 MAPK, but not by PI3-K inhibitors. These results demonstrate, for the first time, that biochanin A, genistein and p-ethylphenol enhance IL-4 production in activated T cells by two independent pathways, PI3-K/PKC/NF-AT and PKC/p38 MAPK/AP-1

The transillumination technique as a method for the assessment of spermatogenesis using medicinal plants: the effect of extracts of black maca (Lepidium meyenii) and camu camu (Myrciaria dubia) on stages of the spermatogenic cycle in male rats.

Science.gov (United States)

Gonzales, Gustavo F; Vasquez, Vanessa Bertha; Gasco, Manuel

2013-10-01

Transillumination technique for assessment of stages of spermatogenic cycle is a useful tool for toxicological studies. This study was designed to determine the effect of two medicinal plants on spermatogenesis in male rats using the transillumination technique. For this, the effect of the combination of a fruit with highest content of ascorbic acid (Myrciaria dubia, camu camu) and extract of black maca (Lepidium meyenii) on seminiferous tubule stages scored by transillumination on intact tubules in adult male rats was assessed. Animals were treated during seven days with vehicle, black maca, camu camu or a mixture of black maca + camu camu and assessed for daily sperm production (DSP), stages of spermatogenic cycle as well as antioxidant activity and levels of flavonoids and polyphenols. Black maca increased stages of spermiation (VII-VIII) and mitosis of germ cells (IX-XI), whereas camu camu increased stages of mitosis (IX-XI) and meiosis (XII). Mixture of maca + camu camu increased stages of spermiation, mitosis and meiosis. All treatments increased DSP (pmaca. In conclusion, M. dubia (camu camu) has potential effects improving spermatogenesis and co-administered with maca increase stages of mitosis, meiosis and spermiation of the spermatogenic cycle as assessed by the transillumination technique. This technique is becoming increasingly a useful tool for assessment spermatogenesis.

Data set on the characterization of the phytoestrogenic extract and isolated compounds of the roots of Inula racemosa Hook F (Asteraceae

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Mangathayaru Kalachaveedu

2018-04-01

Full Text Available The data presented in this article are related to the research article entitled ‘ Phyto estrogenic effect of Inula racemosa Hook. f – A cardio protective root drug in traditional medicine, (Mangathayaru K, Divya R, Srivani T et al., 2018 [1]. It describes the characterization details of the root extract and the compounds isolated from them that were shown to be phytoestrogenic in vivo and in vitro respectively. Keywords: Alantolactone, Isoalantolactone, Stigmasterol glycoside, Inulin

Association of the infusion of Heteropterys aphrodisiaca and endurance training brings spermatogenetic advantages

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Marcos L M Gomes

2011-01-01

Full Text Available The species Heteropterys aphrodisiaca is commonly used as a stimulant by popular medicine in the Cerrado, a savanna-like biome, Brazil. Recent studies have proved its protective effects on testes of animals submitted to treatment using Cyclosporine A, as well as its stimulus effect in increasing testosterone secretion. Therefore, the present study was designed to analyze whether the association of the plant infusion and endurance exercise could potentiate the stimulating effect. The animals were separated into 4 groups: two control (sedentary and trained receiving water and two treated (sedentary and trained receiving the plant infusion daily (104mg/day. The proportion of the seminiferous tubule compartment and interstitium was analyzed. Within the seminiferous epithelium, the number of Sertoli and germ cells were counted in order to evaluate whether the treatment would alter the spermatogenic dynamics, analyzing: the spermatogenic yield, the mitotic and meiotic indexes, the total number of germ cells and the Sertoli cell support capacity. Trained and treated animals showed increased spermatogenic yield and spermatogonia mitosis, and no significant differences in apoptotic indexes. Despite the results showing the same pattern regarding yield and mitotic index, the meiotic index was higher in the sedentary/treated group. Therefore, the H. aphrodisiaca infusion increased both the testosterone production and the spermatogonia mitosis, thus increasing the spermatogenic yield.

Genistein, a phytoestrogen, improves total cholesterol, and Synergy, a prebiotic, improves calcium utilization, but there were no synergistic effects.

Science.gov (United States)

Legette, LeeCole L; Lee, Wang-Hee; Martin, Berdine R; Story, Jon A; Arabshahi, Ali; Barnes, Stephen; Weaver, Connie M

2011-08-01

Prebiotics and phytoestrogens have sparked great interest because evidence indicates that the consumption of these dietary constituents leads to lower cholesterol levels and inhibition of postmenopausal bone loss. The aim of this study was to determine the effect of both a prebiotic (Synergy) and a phytoestrogen (genistein) on bone and blood lipid levels in an animal model of postmenopausal women. A 4-week feeding study was conducted in 5-month-old ovariectomized (OVX) Sprague-Dawley rats to examine the effect of genistein, Synergy (a prebiotic), and genistein and Synergy combined on bone density and strength, calcium metabolism, and lipid biomarkers. There were six treatment groups: sham control, OVX control, OVX rats receiving daily estradiol injections, and OVX rats receiving an AIN-93M diet supplement with 200 ppm genistein, with 5% Synergy or with 200 ppm genistein and 5% Synergy combined. The rats receiving genistein had significantly lower total serum cholesterol concentrations than OVX rats in the control group (17%), OVX rats receiving daily estradiol injections (14%), and OVX rats fed the 5% Synergy diet (19%). Consumption of Synergy improved calcium absorption efficiency (41%) compared with nonconsumption (OVX control). Sham control rats had a significantly higher femoral bone density, as determined by underwater weighing, than did the rats in all of the OVX groups. Genistein consumption restored total and trabecular bone mineral density at the distal femur similar to the levels of sham rats. Genistein supplementation imparts modest heart health benefits and improves bone geometry at the distal femur, and prebiotic consumption (Synergy) results in improved calcium utilization strength in ovariectomized rats, but the combination produced no synergistic effects.

The fate of pharmaceuticals, steroid hormones, phytoestrogens, UV-filters and pesticides during MBR treatment.

Science.gov (United States)

Wijekoon, Kaushalya C; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Nghiem, Long D

2013-09-01

This study examined the relationship between molecular properties and the fate of trace organic contaminants (TrOCs) in the aqueous and solid phases during wastewater treatment by MBR. A set of 29 TrOCs was selected to represent pharmaceuticals, steroid hormones, phytoestrogens, UV-filters and pesticides that occur ubiquitously in municipal wastewater. Both adsorption and biodegradation/transformation were found responsible for the removal of TrOCs by MBR treatment. A connection between biodegradation and molecular structure could be observed while adsorption was the dominant removal mechanism for the hydrophobic (logD>3.2) compounds. Highly hydrophobic (logD>3.2) but readily biodegradable compounds did not accumulate in sludge. In contrast, recalcitrant compounds with a moderate hydrophobicity, such as carbamazepine, accumulated significantly in the solid phase. The results provide a framework to predict the removal and fate of TrOCs by MBR treatment. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Analysis of the Effect of Chronic and Low-Dose Radiation Exposure on Spermatogenic Cells of Male Large Japanese Field Mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant Accident.

Science.gov (United States)

Takino, Sachio; Yamashiro, Hideaki; Sugano, Yukou; Fujishima, Yohei; Nakata, Akifumi; Kasai, Kosuke; Hayashi, Gohei; Urushihara, Yusuke; Suzuki, Masatoshi; Shinoda, Hisashi; Miura, Tomisato; Fukumoto, Manabu

2017-02-01

In this study we analyzed the effect of chronic and low-dose-rate (LDR) radiation on spermatogenic cells of large Japanese field mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident. In March 2014, large Japanese field mice were collected from two sites located in, and one site adjacent to, the FNPP ex-evacuation zone: Tanashio, Murohara and Akogi, respectively. Testes from these animals were analyzed histologically. External dose rate from radiocesium (combined 134 Cs and 137 Cs) in these animals at the sampling sites exhibited 21 μGy/day in Tanashio, 304-365 μGy/day in Murohara and 407-447 μGy/day in Akogi. In the Akogi group, the numbers of spermatogenic cells and proliferating cell nuclear antigen (PCNA)-positive cells per seminiferous tubule were significantly higher compared to the Tanashio and Murohara groups, respectively. TUNEL-positive apoptotic cells tended to be detected at a lower level in the Murohara and Akogi groups compared to the Tanashio group. These results suggest that enhanced spermatogenesis occurred in large Japanese field mice living in and around the FNPP ex-evacuation zone. It remains to be elucidated whether this phenomenon, attributed to chronic exposure to LDR radiation, will benefit or adversely affect large Japanese field mice.

Molecular analysis of the genus Asparagus based on matK sequences and its application to identify A. racemosus, a medicinally phytoestrogenic species.

Science.gov (United States)

Boonsom, Teerawat; Waranuch, Neti; Ingkaninan, Kornkanok; Denduangboripant, Jessada; Sukrong, Suchada

2012-07-01

The plant Asparagus racemosus is one of the most widely used sources of phytoestrogens because of its high content of the steroidal saponins, shatavarins I-IV, in roots. The dry root of A. racemosus, known as "Rak-Sam-Sip" in Thai, is one of the most popular herbal medicines, used as an anti-inflammatory, an aphrodisiac and a galactagogue. Recently, the interest in plant-derived estrogens has increased tremendously, making A. racemosus particularly important and a possible target for fraudulent labeling. However, the identification of A. racemosus is generally difficult due to its similar morphology to other Asparagus spp. Thus, accurate authentication of A. racemosus is essential. In this study, 1557-bp nucleotide sequences of the maturase K (matK) gene of eight Asparagus taxa were analyzed. A phylogenetic relationship based on the matK gene was also constructed. Ten polymorphic sites of nucleotide substitutions were found within the matK sequences. A. racemosus showed different nucleotide substitutions to the other species. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the matK gene was developed to discriminate A. racemosus from others. Only the 650-bp PCR product from A. racemosus could be digested with BssKI into two fragments of 397 and 253-bp while the products of other species remained undigested. Ten commercially crude drugs were analyzed and revealed that eight samples were derived from A. racemosus while two samples of that were not. Thus, the PCR-RFLP analysis of matK gene was shown to be an effective method for authentication of the medicinally phytoestrogenic species, A. racemosus. Copyright © 2012 Elsevier B.V. All rights reserved.

Differential binding with ERα and ERβ of the phytoestrogen-rich plant Pueraria mirifica

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C. Boonchird

2010-02-01

Full Text Available Variations in the estrogenic activity of the phytoestrogen-rich plant, Pueraria mirifica, were determined with yeast estrogen screen (YES consisting of human estrogen receptors (hER hERα and hERβ and human transcriptional intermediary factor 2 (hTIF2 or human steroid receptor coactivator 1 (hSRC1, respectively, together with the β-galactosidase expression cassette. Relative estrogenic potency was expressed by determining the β-galactosidase activity (EC50 of the tuber extracts in relation to 17β-estradiol. Twenty-four and 22 of the plant tuber ethanolic extracts interacted with hERα and hERβ, respectively, with a higher relative estrogenic potency with hERβ than with hERα. Antiestrogenic activity of the plant extracts was also determined by incubation of plant extracts with 17β-estradiol prior to YES assay. The plant extracts tested exhibited antiestrogenic activity. Both the estrogenic and the antiestrogenic activity of the tuber extracts were metabolically activated with the rat liver S9-fraction prior to the assay indicating the positive influence of liver enzymes. Correlation analysis between estrogenic potency and the five major isoflavonoid contents within the previously HPLC-analyzed tuberous samples namely puerarin, daidzin, genistin, daidzein, and genistein revealed a negative result.

Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women.

Science.gov (United States)

Teas, Jane; Hurley, Thomas G; Hebert, James R; Franke, Adrian A; Sepkovic, Daniel W; Kurzer, Mindy S

2009-05-01

Seaweed and soy foods are consumed daily in Japan, where breast cancer rates for postmenopausal women are significantly lower than in the West. Likely mechanisms include differences in diet, especially soy consumption, and estrogen metabolism. Fifteen healthy postmenopausal women participated in this double-blind trial of seaweed supplementation with soy challenge. Participants were randomized to 7 wk of either 5 g/d seaweed (Alaria) or placebo (maltodextrin). During wk 7, participants also consumed a daily soy protein isolate (2 mg isoflavones/kg body weight). After a 3-wk washout period, participants were crossed over to the alternate supplement schedule. There was an inverse correlation between seaweed dose (mg/kg body weight) and serum estradiol (E2) (seaweed-placebo = y = -2.29 x dose + 172.3; r = -0.70; P = 0.003), [corrected] which was linear across the range of weights. Soy supplementation increased urinary daidzein, glycitein, genistein, and O-desmethylangolensin (P = 0.0001) and decreased matairesinol and enterolactone (P seaweed plus soy (SeaSoy) increased urinary excretion of 2-hydroxyestrogen (2-OHE) (P = 0.0001) and the ratio of 2-OHE:16alpha-hydroxyestrone (16alphaOHE(1)) (P = 0.01). For the 5 equol excretors, soy increased urinary equol excretion (P = 0.0001); the combination of SeaSoy further increased equol excretion by 58% (P = 0.0001). Equol producers also had a 315% increase in 2:16 ratio (P = 0.001) with SeaSoy. Seaweed favorably alters estrogen and phytoestrogen metabolism and these changes likely include modulation of colonic bacteria.

Gonadotrophins, testosterone and spermatogenesis in neonatally irradiated male rates: evidence for a role of the Sertoli cell in follicle-stimulating hormone feedback

International Nuclear Information System (INIS)

De Jong, F.H.; Sharpe, R.M.

1977-01-01

Peripheral concentrations of FSH in the male rat seem to be regulated in parts by a protein hormone, inhibin, which originates from the testes. In an attempt to ascertain which type of testicular cell secretes inhibin, groups of male rats were irradiated prenatally or on days 4, 6 or 8 of postnatal life, and killed at 21, 51 or 81 days of age together with castrated and intact controls. The concentrations of FSH and LH in the pituitary gland, and FSH, LH and testosterone in the plasma were estimated for each animal, and the numbers of each class of intratubular cell in the testes were calculated. Rats irradiated neonatally had fewer Sertoli cells than controls at all ages studied, while the numbers of Sertoli cells in rats irradiated prenatally were higher than those in controls on day 21. The number of spermatogenic cells was usually decreased in rats irradiated postnatally. In the rats irradiated prenatally normal numbers of spermatogenic cells were found at day 51. Numbers of spermatogenic cells were significantly correlated with the number of Sertoli cells at the ages of 51 and 81 days. The concentration of FSH in the plasma usually increased in the postnatally irradiated animals on days 21 and 51, but not on day 81; prenatal irradiation did not result in altered levels of FSH at any age. Peripheral levels of LH and testosterone were not affected by irradiation. The concentration of FSH in the plasma was negatively correlated with the number of Sertoli cells in all age groups, whereas significant correlations between the levels of FSH and the number of spermatogenic cells were only found at days 51 and 81. It is concluded from these data that the Sertoli cell is the most likely source of inhibin. (author)

第一节 Morris水迷宫实验

African Journals Online (AJOL)

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After the individual treatments for 8 weeks ended, the serum levels of estradiol ... Transcutaneous electrical acupoint stimulation (TEAS) is an innovative and .... awareness of HRT was poor, which was influenced by menopausal, working and ... Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and.

Effects of Vehicles and Enhancers on the Skin Permeation of Phytoestrogenic Diarylheptanoids from Curcuma comosa.

Science.gov (United States)

Tuntiyasawasdikul, Sarunya; Limpongsa, Ekapol; Jaipakdee, Napaphak; Sripanidkulchai, Bungorn

2017-04-01

Curcuma comosa (C. comosa) is widely used in traditional medicine as a dietary supplement for health promotion in postmenopausal women in Thailand. It contains several diarylheptanoids, which are considered to be a novel class of phytoestrogens. However, the diarylheptanoids isolated from the plant rhizome are shown to have low oral bioavailability and faster elimination characteristics. The aim of this study was to investigate the permeation behavior of the active compounds of diarylheptanoids. The effects of binary vehicle systems and permeation enhancers on diarylheptanoids permeation and accumulation within the skin were studied using side-by-side diffusion cells through the porcine ear skin. Among the tested binary vehicle systems, the ethanol/water vehicle appeared to be the most effective system for diarylheptanoids permeation with the highest flux and shortest lag time. The presence of transcutol in the vehicle system significantly increased diarylheptanoid's permeation and accumulation within the skin in a concentration-dependent manner. Although the presence of terpenes in formulation decreased the flux of diarylheptanoids, it raised the amount of diarylheptanoids retained within the skin substantially. Based on the feasibility of diarylheptanoid permeation, C. comosa extract should be further developed into an effective transdermal product for health benefits and hormone replacement therapy.

Phytoestrogen bakuchiol exhibits in vitro and in vivo anti-breast cancer effects by inducing S phase arrest and apoptosis

Directory of Open Access Journals (Sweden)

Li eLi

2016-05-01

Full Text Available Phytoestrogen has been proposed as an alternative to hormone replacement therapy, which has been demonstrated to promote a high risk of breast cancer. However, the effect of phytoestrogen on breast cancer development has not been fully understood. Bakuchiol is an active ingredient of a traditional Chinese herbal medicine Fructus Psoraleae, the dried ripe fruit of Psoralea corylifolia L. (Fabaceae. The in vitro and in vivo estrogenic activities and anti-breast cancer effects of bakuchiol have not been well studied. We found that bakuchiol induced the GFP expression in transgenic medaka (Oryzias melastigma, Tg, Chg:GFP dose-dependently (0-1 µg/ml, demonstrating its in vivo estrogenic activity. Low dose of bakuchiol (1 µg/ml induced the cell proliferation and ERα expression in MCF-7 cells, which could be blocked by the antiestrogen ICI 182780, suggesting the in vitro estrogenic activity of bakuchiol. Our data indicated that high doses of bakuchiol (>2 µg/ml inhibited breast cancer cell growth, with a stronger antiproliferative effect than resveratrol, a widely studied analogue of bakuchiol. High doses of bakuchiol (4 µg/ml, 7 µg/ml and 10 µg/ml were used for the further in vitro anti-breast cancer studies. Bakuchiol induced ERβ expression and suppressed ERα expression in MCF-7 cells. It also induced S phase arrest in both MCF-7 and MDA-MB-231 cells, which could be rescued by caffeine. Knock-down of p21 also marginally rescued S phase arrest in MCF-7 cells. The S phase arrest was accompanied by the upregulation of ATM, P-Cdc2 (Tyr15, Myt1, P-Wee1 (Ser642, p21 and Cyclin B1, suggesting that blocking of Cdc2 activation may play an important role in bakuchiol-induced S phase arrest. Furthermore, bakuchiol induced cell apoptosis and disturbed mitochondrial membrane potential in MCF-7 cells. The bakuchiol-induced apoptosis was associated with increased expression of Caspase family and Bcl-2 family proteins, suggesting that bakuchiol may induce

Osteoporosis and prevention. Assessment of mineral density, geometry and biomechanics of bone by means of peripheral quantitative Computed Tomography (pQCT) in premenopausal women assuming phytoestrogens; Osteoporosi e fitoestrogeni: valutazione della densita' minerale ossea mediante tomografia computerizzata quantitativa periferica nelle donne lattoovovegetariane nella premenopausa

Energy Technology Data Exchange (ETDEWEB)

Di Leo, C; Tarolo, G L; Bestetti, A; Tagliabue, L; Del Sole, A; Alberti, G [Ospedale San Paolo, Milan (Italy). Servizio di Medicina Nucleare; Cestaro, B [Milan Univ., Milan (Italy). Cattedra e Scuola di Specializzazione in Medicina Nucleare; Pepe, L [ACN-L' Accessorio Nucleare, Cerro Maggiore, MI (Italy). Lab. Nucleari

2000-04-01

Aim of the work was to describe the noninvasive assessment of bone mineral density, geometrical and biochemical properties in premenopausal women with dietary intake of phytoestrogens and comparison of these parameters with those of age-matched female subjects with Mediterranean dietary intake lacking in these substances. Volumetric cortical, trabecular and total mineral density and bone geometrical properties were evaluated with peripheral quantitative computed tomography (pQCT) at the distal radius of the non dominant forearm. pQCT showed higher bone mineral density (total and trabecular) and SSI values in premenopausal with dietary intake of phytoestrogens. Despite the lack of statistical significance, these preliminary results, should further support the few literature findings about the potential role of phytoestrogens consumption in preventing trabecular bone loss. However, further studies are warranted to evaluate definitively postmenopausal osteoporosis. [Italian] Scopo del lavoro e' quello di studiare in modo non-invasivo la densita' minerale, le caratteristiche geometriche e biomeccaniche dell'osso in donne lattoovovegetariane nella premenopausa che assumevano con la dieta fitoestrogeni e confrontare questi dati con quelli di donne anch'esse in premenopausa, con dieta di tipo mediterraneo assolutamente priva di questi elementi con azione simil-ormonale. La densita' minerale, le proprieta' geometriche meccaniche dell'osso sono state valutate a livello del radio ultradistale non dominante mediante tomografia computerizzata (TC) quantitativa periferica, che nelle donne in premenopausa con dieta ricca di fitoestrogeni ha evidenziato valori della densita' minerale ossea totale, trabecolare e di resistenza ossea piu' elevati, anche se in modo non significativo, rispetto a quelli dei controlli con dieta mediterranea. Questi risultati preliminari suggerirebbero come l'assunzione quotidiana di fitoestrogeni attraverso la soia potrebbe accompagnarsi a un maggiore

Osteoporosis and prevention. Assessment of mineral density, geometry and biomechanics of bone by means of peripheral quantitative Computed Tomography (pQCT) in premenopausal women assuming phytoestrogens; Osteoporosi e fitoestrogeni: valutazione della densita' minerale ossea mediante tomografia computerizzata quantitativa periferica nelle donne lattoovovegetariane nella premenopausa

Energy Technology Data Exchange (ETDEWEB)

Di Leo, C.; Tarolo, G.L.; Bestetti, A.; Tagliabue, L.; Del Sole, A.; Alberti, G. [Ospedale San Paolo, Milan (Italy). Servizio di Medicina Nucleare; Cestaro, B. [Milan Univ., Milan (Italy). Cattedra e Scuola di Specializzazione in Medicina Nucleare; Pepe, L. [ACN-L' Accessorio Nucleare, Cerro Maggiore, MI (Italy). Lab. Nucleari

2000-04-01

Aim of the work was to describe the noninvasive assessment of bone mineral density, geometrical and biochemical properties in premenopausal women with dietary intake of phytoestrogens and comparison of these parameters with those of age-matched female subjects with Mediterranean dietary intake lacking in these substances. Volumetric cortical, trabecular and total mineral density and bone geometrical properties were evaluated with peripheral quantitative computed tomography (pQCT) at the distal radius of the non dominant forearm. pQCT showed higher bone mineral density (total and trabecular) and SSI values in premenopausal with dietary intake of phytoestrogens. Despite the lack of statistical significance, these preliminary results, should further support the few literature findings about the potential role of phytoestrogens consumption in preventing trabecular bone loss. However, further studies are warranted to evaluate definitively postmenopausal osteoporosis. [Italian] Scopo del lavoro e' quello di studiare in modo non-invasivo la densita' minerale, le caratteristiche geometriche e biomeccaniche dell'osso in donne lattoovovegetariane nella premenopausa che assumevano con la dieta fitoestrogeni e confrontare questi dati con quelli di donne anch'esse in premenopausa, con dieta di tipo mediterraneo assolutamente priva di questi elementi con azione simil-ormonale. La densita' minerale, le proprieta' geometriche meccaniche dell'osso sono state valutate a livello del radio ultradistale non dominante mediante tomografia computerizzata (TC) quantitativa periferica, che nelle donne in premenopausa con dieta ricca di fitoestrogeni ha evidenziato valori della densita' minerale ossea totale, trabecolare e di resistenza ossea piu' elevati, anche se in modo non significativo, rispetto a quelli dei controlli con dieta mediterranea. Questi risultati preliminari suggerirebbero come l'assunzione quotidiana di fitoestrogeni

Serum androgen binding protein and follicle stimulating hormone as indices of Sertoli cell function in the irradiated testis

International Nuclear Information System (INIS)

Delic, J.I.; Hendry, J.H.; Shalet, S.M.; Morris, I.D.

1986-01-01

The present study presents evidence of radiation-induced Sertoli cell damage in both the pubertal and adult rat. The indirect measurement of Sertoli cell function, serum follicle stimulating hormone (FSH), in general mirrored the changes seen in androgen binding protein (ABP), again indicating Sertoli cell dysfunction. Although FSH remained elevated in adult rats after 5 Gy and above and in pubertal rats after 10 and 20 Gy, the elevation was not as great as that observed in castrates. This suggests that FSH secretion was still inhibited by some factor. As ABP was reduced to near 'background' (castrate) levels after these high doses, suggesting Sertoli cell dysfunction, this may indicate that serum ABP levels may not adequately reflect all Sertoli cell functions. Alternatively FSH may have been inhibited by by Leydig cell androgens, which have been demonstrated to modulate, in part, FSH secretion. Although the Leydig cells were damaged, androgen secretion was not entirely reduced during the study. In general, FSH was elevated when severe damage to spermatogenesis was noted. Whether the changes were related to the absence of a specific spermatogenic cell type could not be determined. (UK)

Anti-diabetic and spermatogenic activity of Cocculus hirsutus (L) Diels

African Journals Online (AJOL)

Administrator

2007-05-16

May 16, 2007 ... lete or relative insufficiency of insulin secretion and insulin action (Balkau .... do not stimulate the pancreas and do not elevate circul- ating insulin levels. .... Physiology, section 7, Endocrinology, Am. Physiol. soc. Washington,.

Effects of the phytoestrogen genistein on bone metabolism in osteopenic postmenopausal women: a randomized trial.

Science.gov (United States)

Marini, Herbert; Minutoli, Letteria; Polito, Francesca; Bitto, Alessandra; Altavilla, Domenica; Atteritano, Marco; Gaudio, Agostino; Mazzaferro, Susanna; Frisina, Alessia; Frisina, Nicola; Lubrano, Carla; Bonaiuto, Michele; D'Anna, Rosario; Cannata, Maria Letizia; Corrado, Francesco; Adamo, Elena Bianca; Wilson, Steven; Squadrito, Francesco

2007-06-19

Observational studies and small trials of short duration suggest that the isoflavone phytoestrogen genistein reduces bone loss, but the evidence is not definitive. To assess the effects of genistein on bone metabolism in osteopenic postmenopausal women. Randomized, double-blind, placebo-controlled trial. 3 university medical centers in Italy. 389 postmenopausal women with a bone mineral density (BMD) less than 0.795 g/cm2 at the femoral neck and no significant comorbid conditions. After a 4-week stabilization period during which participants received a low-soy, reduced-fat diet, participants were randomly assigned to receive placebo (n = 191) or 54 mg of genistein (n = 198) daily for 24 months. Both the genistein and placebo tablets contained calcium and vitamin D. The primary outcome was BMD at the anteroposterior lumbar spine and femoral neck at 24 months. Secondary outcomes were serum levels of bone-specific alkaline phosphatase and insulin-like growth factor I, urinary excretion of pyridinoline and deoxypyridinoline, and endometrial thickness. Data on adverse events were also collected. At 24 months, BMD had increased in genistein recipients and decreased in placebo recipients at the anteroposterior lumbar spine (change, 0.049 g/cm2 [95% CI, 0.035 to 0.059] vs. -0.053 g/cm2 [CI, -0.058 to -0.035]; difference, 0.10 g/cm2 [CI, 0.08 to 0.12]; P power to evaluate adverse effects. Twenty-four months of treatment with genistein has positive effects on BMD in osteopenic postmenopausal women. ClinicalTrials.gov registration number: NCT00355953.

Interaction between Y chromosome haplogroup O3* and 4-n-octylphenol exposure reduces the susceptibility to spermatogenic impairment in Han Chinese.

Science.gov (United States)

Hu, Weiyue; Chen, Minjian; Ji, Juan; Qin, Yufeng; Zhang, Feng; Xu, Miaofei; Wu, Wei; Du, Guizhen; Wu, Di; Han, Xiumei; Jin, Li; Xia, Yankai; Lu, Chuncheng; Wang, Xinru

2017-10-01

Certain genetic background (mainly Y chromosome haplogroups, Y-hg) may modify the susceptibility of certain environmental exposure to some diseases. Compared with respective main effects of genetic background or environmental exposure, interactions between them reflect more realistic combined effects on the susceptibility to a disease. To identify the interactions on spermatogenic impairment, we performed Y chromosome haplotyping and measurement of 9 urinary phenols concentrations in 774 infertile males and 520 healthy controls in a Han Chinese population, and likelihood ratio tests were used to examine the interactions between Y-hgs and phenols. Originally, we observed that Y-hg C and Y-hg F * might modify the susceptibility to male infertility with urinary 4-n-octylphenol (4-n-OP) level (P inter = 0.005 and 0.019, respectively). Subsequently, based on our results, two panels were tested to identify the possible protective sub-branches of Y-hg F * to 4-n-OP exposure, and Y-hg O3 * was uncovered to interact with 4-n-OP (P inter = 0.019). In conclusion, while 4-n-OP shows an adverse effect on spermatogenesis, Y-hg O3 * makes individuals more adaptive to such an effect for maintaining basic reproductive capacity. Copyright © 2017 Elsevier Inc. All rights reserved.

Compounds from Cynomorium songaricum with Estrogenic and Androgenic Activities Suppress the Oestrogen/Androgen-Induced BPH Process.

Science.gov (United States)

Wang, Xueni; Tao, Rui; Yang, Jing; Miao, Lin; Wang, Yu; Munyangaju, Jose Edouard; Wichai, Nuttapong; Wang, Hong; Zhu, Yan; Liu, Erwei; Chang, Yanxu; Gao, Xiumei

2017-01-01

To investigate the phytoestrogenic and phytoandrogenic activities of compounds isolated from CS and uncover the role of CS in prevention of oestrogen/androgen-induced BPH. Cells were treated with CS compounds, and immunofluorescence assay was performed to detect the nuclear translocation of ER α or AR in MCF-7 or LNCaP cells; luciferase reporter assay was performed to detect ERs or AR transcriptional activity in HeLa or AD293 cells; MTT assay was performed to detect the cell proliferation of MCF-7 or LNCaP cells. Oestrogen/androgen-induced BPH model was established in rat and the anti-BPH, anti-estrogenic, and anti-androgenic activities of CS in vivo were further investigated. The nuclear translocation of ER α was stimulated by nine CS compounds, three of which also stimulated AR translocation. The transcriptional activities of ER α and ER β were induced by five compounds, within which only ECG induced AR transcriptional activity as well. Besides, ECG stimulated the proliferation of both MCF-7 cells and LNCaP cells. CS extract suppressed oestrogen/androgen-induced BPH progress in vivo by downregulation of E2 and T level in serum and alteration of the expressions of ER α , ER β , and AR in the prostate. Our data demonstrates that compounds from CS exhibit phytoestrogenic and phytoandrogenic activities, which may contribute to inhibiting the oestrogen/androgen-induced BPH development.

Endosulfan inhibiting the meiosis process via depressing expressions of regulatory factors and causing cell cycle arrest in spermatogenic cells.

Science.gov (United States)

Guo, Fang-Zi; Zhang, Lian-Shuang; Wei, Jia-Liu; Ren, Li-Hua; Zhang, Jin; Jing, Li; Yang, Man; Wang, Ji; Sun, Zhi-Wei; Zhou, Xian-Qing

2016-10-01

Endosulfan is a persistent organic pollutant and widely used in agriculture as a pesticide. It is present in air, water, and soil worldwide; therefore, it is a health risk affecting especially the reproductive system. The aim of this study was to evaluate the toxicity of endosulfan in the reproductive system. To investigate the effect of endosulfan on meiosis process, 32 rats were divided into four groups, treated with 0, 1, 5, and 10 mg/kg/day endosulfan, respectively, and sacrificed after the 21 days of treatments. Results show that endosulfan caused the reductions in sperm concentration and motility rate, which resulted into an increased in sperm abnormality rate; further, endosulfan induced downregulation of spermatogenesis- and oogenesis-specific basic helix-loop-helix transcription factor (Sohlh1) which controls the switch on meiosis in mammals, as well cyclin A1, cyclin-dependent kinases 1 (CDK1), and cyclin-dependent kinases 2 (CDK2). In vitro, endosulfan induced G2/M phase arrest in the spermatogenic cell cycle and caused proliferation inhibition. Moreover, endosulfan induced oxidative stress and DNA damage in vivo and vitro. The results suggested that endosulfan could inhibit the start of meiosis by downregulating the expression of Sohlh1 and induce G2/M phase arrest of cell cycle by decreasing the expression of cyclin A1, CDK1, and CDK2 via oxidative damage, which inhibits the meiosis process, and therefore decrease the amount of sperm.

Thyroid and male reproduction

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Anand Kumar

2014-01-01

Full Text Available Male reproduction is governed by the classical hypothalamo-hypophyseal testicular axis: Hypothalamic gonadotropin releasing hormone (GnRH, pituitary luteinizing hormone (LH and follicle stimulating hormone (FSH and the gonadal steroid, principally, testosterone. Thyroid hormones have been shown to exert a modulatory influence on this axis and consequently the sexual and spermatogenic function of man. This review will examine the modulatory influence of thyroid hormones on male reproduction.

Effect of maca supplementation on bovine sperm quantity and quality followed over two spermatogenic cycles.

Science.gov (United States)

Clément, C; Kneubühler, J; Urwyler, A; Witschi, U; Kreuzer, M

2010-07-15

Maca (Lepidium meyenii Walpers), is an Andean crop that grows between 3,800 and 4,500 m a.s.l. The persistent interest in this plant is based on its assumed effects on fertility of male mammals due to the prevalence of certain, partially specific, secondary compounds. The present study aimed at evaluating the effect of maca supplementation on quality and quantity of semen, mating behavior, and clinical status of peripubertal breeding bulls. The experiment followed a cross-over design lasting for 23 wk with 3 wk of adaptation and baseline measurements, and 2 x 10 wk of treatment feeding thus covering two times the complete 8-wk spermatogenic cycle. Seventy-eight 55 wk to 84 wk old breeding bulls received either no maca (control) or maca (233 mg dried hypocotyls/kg body weight/day) for 10 wk followed by 10 wk without maca (maca early) or maca only in the last 10 wk (maca late). Measurements were always made in the last 2 wk of each period. Apart from standard analyses, ejaculates were analyzed by flow cytometry. Data was evaluated by analysis of variance considering the repeated measurement structure of the data. Significant treatment by measurement period indicated direct or carry-over effects of maca. Maca supplementation had no direct effect on body weight, testes circumference, rectal temperature, mating behavior, and ejaculate volume. However, supplementing maca in the first 10 wk period increased the number of sperms in the second 10 wk period, i.e., when the animals no longer received maca. The DNA fragmentation index and the visually assessed motility of the sperms of bulls, that initially showed a borderline sperm quality, were significantly improved with early maca supplementation, while no such effect was observed in the two other groups. No effects occurred in the proportion of intact sperm plasma membranes or acrosomes or both. In conclusion, maca supplementation seems to improve sperm quantity and quality of bulls to a certain degree, while mating

Characterization and possible function of glyceraldehyde-3-phosphate dehydrogenase-spermatogenic protein GAPDHS in mammalian sperm.

Science.gov (United States)

Margaryan, Hasmik; Dorosh, Andriy; Capkova, Jana; Manaskova-Postlerova, Pavla; Philimonenko, Anatoly; Hozak, Pavel; Peknicova, Jana

2015-03-08

Sperm proteins are important for the sperm cell function in fertilization. Some of them are involved in the binding of sperm to the egg. We characterized the acrosomal sperm protein detected by a monoclonal antibody (MoAb) (Hs-8) that was prepared in our laboratory by immunization of BALB/c mice with human ejaculated sperms and we tested the possible role of this protein in the binding assay. Indirect immunofluorescence and immunogold labelling, gel electrophoresis, Western blotting and protein sequencing were used for Hs-8 antigen characterization. Functional analysis of GAPDHS from the sperm acrosome was performed in the boar model using sperm/zona pellucida binding assay. Monoclonal antibody Hs-8 is an anti-human sperm antibody that cross-reacts with the Hs-8-related protein in spermatozoa of other mammalian species (boar, mouse). In the immunofluorescence test, Hs-8 antibody recognized the protein localized in the acrosomal part of the sperm head and in the principal piece of the sperm flagellum. In immunoblotting test, MoAb Hs-8 labelled a protein of 45 kDa in the extract of human sperm. Sequence analysis identified protein Hs-8 as GAPDHS (glyceraldehyde 3-phosphate dehydrohenase-spermatogenic). For this reason, commercial mouse anti-GAPDHS MoAb was applied in control tests. Both antibodies showed similar staining patterns in immunofluorescence tests, in electron microscopy and in immunoblot analysis. Moreover, both Hs-8 and anti-GAPDHS antibodies blocked sperm/zona pellucida binding. GAPDHS is a sperm-specific glycolytic enzyme involved in energy production during spermatogenesis and sperm motility; its role in the sperm head is unknown. In this study, we identified the antigen with Hs8 antibody and confirmed its localization in the apical part of the sperm head in addition to the principal piece of the flagellum. In an indirect binding assay, we confirmed the potential role of GAPDHS as a binding protein that is involved in the secondary sperm

Suppression of dendritic cells' maturation and functions by daidzein, a phytoestrogen

International Nuclear Information System (INIS)

Yum, Min Kyu; Jung, Mi Young; Cho, Daeho; Kim, Tae Sung

2011-01-01

Isoflavones are ubiquitous compounds in foods and in the environment in general. Daidzein and genistein, the best known of isoflavones, are structurally similar to 17β-estradiol and known to exert estrogenic effects. They also evidence a broad variety of biological properties, including antioxidant, anti-carcinogenic, anti-atherogenic and anti-osteoporotic activities. Previously, daidzein was reported to increase the phagocytic activity of peritoneal macrophages and splenocyte proliferation, and to inhibit nitric oxide (NO) production in macrophages. However, its potential impacts on immune response in dendritic cells (DCs), antigen-presenting cells that link innate and adaptive immunity, have yet to be clearly elucidated. In this study, we evaluated the effects of isoflavones on the maturation and activation of DCs. Isoflavones (formononetin, daidzein, equol, biochanin A, genistein) were found to differentially affect the expression of CD86, a costimulatory molecule, on lipopolysaccharide (LPS)-stimulated DCs. In particular, daidzein significantly and dose-dependently inhibited the expression levels of maturation-associated cell surface markers including CD40, costimulatory molecules (CD80, CD86), and major histocompatibility complex class II (I-A b ) molecule on LPS-stimulated DCs. Daidzein also suppressed pro-inflammatory cytokine production such as IL-12p40, IL-6 and TNF-α, whereas it didn't affect IL-10 and IL-1β expression. Furthermore, daidzein enhanced endocytosis and inhibited the allo-stimulatory ability of LPS-stimulated DCs on T cells, indicating that daidzein treatment can inhibit the functional maturation of DCs. These results demonstrate that daidzein may exhibit immunosuppressive activity by inhibiting the maturation and activation of DCs. -- Highlights: ► Daidzein inhibited expression of maturation-associated cell surface markers in DCs. ► Daidzein suppressed expression of pro-inflammatory cytokines in LPS-stimulated DCs. ► Daidzein

Profiling spermatogenic failure in adult testes bearing Sox9-deficient Sertoli cells identifies genes involved in feminization, inflammation and stress

Directory of Open Access Journals (Sweden)

Barrionuevo Francisco

2010-12-01

Full Text Available Abstract Background Sox9 (Sry box containing gene 9 is a DNA-binding transcription factor involved in chondrocyte development and sex determination. The protein's absence in testicular Sertoli nurse cells has been shown to disrupt testicular function in adults but little is known at the genome-wide level about molecular events concomitant with testicular break-down. Methods To determine the genome-wide effect on mRNA concentrations triggered by the absence of Sox9 in Sertoli cells we analysed adult testicular tissue from wild-type versus mutant mice with high-density oligonucleotide microarrays and integrated the output of this experiment with regulatory motif predictions and protein-protein network data. Results We report the genome-wide mRNA signature of adult testes lacking Sox9 in Sertoli cells before and after the onset of late spermatogenic failure as compared to fertile controls. The GeneChip data integrated with evolutionarily conserved Sox9 DNA binding motifs and regulatory network data identified genes involved in feminization, stress response and inflammation. Conclusions Our results extend previous observations that genes required for female gonadogenesis are up-regulated in the absence of Sox9 in fetal Sertoli cells to the adult stage. Importantly, we identify gene networks involved in immunological processes and stress response which is reminiscent of a phenomenon occurring in a sub-group of infertile men. This suggests mice lacking Sox9 in their Sertoli cells to be a potentially useful model for adult human testicular failure.

Blackcurrant Anthocyanins Increase the Levels of Collagen, Elastin, and Hyaluronic Acid in Human Skin Fibroblasts and Ovariectomized Rats

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Naoki Nanashima

2018-04-01

Full Text Available Blackcurrants (Ribes nigrum L. contain high levels of anthocyanin polyphenols, which have beneficial effects on health, owing to their antioxidant and anticarcinogenic properties. Phytoestrogens are plant-derived substances with estrogenic activity, which could have beneficial effects on the skin. Estradiol secretion decreases during menopause, reducing extracellular matrix (ECM component production by skin fibroblasts. Using a normal human female skin fibroblast cell line (TIG113 and ovariectomized rats, the present study investigated whether an anthocyanin-rich blackcurrant extract (BCE and four blackcurrant anthocyanins have novel phytoestrogenic activities that could benefit the skin in menopausal women. In TIG113 cells, a microarray and the Ingenuity® Pathway Analysis showed that 1.0 μg/mL of BCE upregulated the expression of many estrogen signaling-related genes. A quantitative RT-PCR analysis confirmed that BCE (1.0 or 10.0 μg/mL and four types of anthocyanins (10 μM altered the mRNA expression of ECM proteins and enzymes involved in ECM turnover. Immunofluorescence staining indicated that the anthocyanins stimulated the expression of ECM proteins, such as collagen (types I and III and elastin. Dietary administration of 3% BCE to ovariectomized rats for 3 months increased skin levels of collagen, elastin, and hyaluronic acid. This is the first study to show that blackcurrant phytoestrogens have beneficial effects on skin experimental models.

Prescription profile of Chinese herbal products containing coumestrol, genestein, and/or daidzein among female users: an analysis of national health insurance data in Taiwan between 1997 and 2007

OpenAIRE

Wu, Chien-Tung; Tzeng, Jeng-Nan; Lai, Jung-Nien; Tsan, Shun-Hua; Wang, Jung-Der

2012-01-01

Abstract Background Some Chinese herbs contain several kinds of phytoestrogens, and these herbs are commonly prescribed in Taiwan. Phytoestrogens may influence the effects of estrogen in females, although their activities are weak. This study aims to identify the risk and analyze the prescription profile of commonly used phytoestrogenic herbs in Taiwan. Methods The study analyzed women who had been prescribed phytoestrogenic herbs including coumestrol, genistein and/or daidzein between 1997 a...

Morphofunctional evaluation of the testicle and the spermatogenic process of adult white-eyed parakeets (Aratinga leucophthalma MULLER, 1776) during the different seasons of the year.

Science.gov (United States)

Peixoto, J V; Paula, T A R; Balarini, M K; Matta, S L P; Santos, J A D; Lima, C B; Peixoto, G V

2012-08-01

In this experiment, testicle fragments of 14 adult White-eyed Parakeets (Aratinga leucophthalma) were evaluated as for their seasonal reproductive activities using the following quantitative parameters: average thickness of the testicular tunica albuginea, volumetric proportion of tubular and extratubular compartments, average diameter of the seminiferous tubules and corporal weight. Parameters were created for qualitative evaluations of the degree of spermatogenic development. In this experiment, all the animals were distributed into four groups, and their testicular fragments were collected during the middle of summer, fall, winter and spring. The animals were submitted to volatile general anaesthesia, and a biopsy was made by celioscopy. The fragments collected were processed histologically. The slides were prepared and later evaluated by using an optical microscope. The average seasonal values of the corporal weight increased, starting in the winter and reaching the peak during the spring. A seasonal testicle cycle was observed, because, in the spring, the testicles showed values for the quantitative and qualitative parameters of spermatic production compatible with the period of greater activity, while the opposite thing happened during the fall. Our data indicate that the parameters of sperm production may be correlated with daily light rather than with air humidity. © 2012 Blackwell Verlag GmbH.

The Effect of Soybean-Derived Phytoestrogens on Concentrations of Plasma Isoflavones, 15-keto-13,14-dihydroprostaglandin F2α and Progesterone in Dairy Cows

Directory of Open Access Journals (Sweden)

Jarmila Watzková

2010-01-01

Full Text Available The objective of the study was to determine the effect of soybean-derived phytoestrogens and their metabolites on the activity of sex hormones during the oestrous cycle in multiparous lactating dairy cows. The experiment was carried out on 4 multiparous lactating Holstein cows in the form of replicated Latin square in double reversal design. The experiment in the total length of 168 days was divided into 4 periods of 42 days, each consisting of a 21-day preliminary period and a 21-day collecting period. Cows were divided into 2 groups of 2 cows. The control group (C was fed a diet based on extruded rapeseed cake while the experimental group (S was fed a diet containing extruded full-fat soya. The intake of total isoflavones was 3297 mg/d in S and 58.0 mg/d in C (P P P > 0.05. Plasma concentration of prostaglandine PGFM throughout the oestrous cycle in the experimental group (S tended to be higher (P = 0.095 than in the control group (C. No differences in the length of the oestrous cycle between the cows fed different diets were observed.

Suppression of dendritic cells' maturation and functions by daidzein, a phytoestrogen

Energy Technology Data Exchange (ETDEWEB)

Yum, Min Kyu; Jung, Mi Young [School of Life Sciences and Biotechnology, Korea University, Seoul 136-701 (Korea, Republic of); Cho, Daeho [Department of Life Science, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Kim, Tae Sung, E-mail: tskim@korea.ac.kr [School of Life Sciences and Biotechnology, Korea University, Seoul 136-701 (Korea, Republic of)

2011-12-15

Isoflavones are ubiquitous compounds in foods and in the environment in general. Daidzein and genistein, the best known of isoflavones, are structurally similar to 17{beta}-estradiol and known to exert estrogenic effects. They also evidence a broad variety of biological properties, including antioxidant, anti-carcinogenic, anti-atherogenic and anti-osteoporotic activities. Previously, daidzein was reported to increase the phagocytic activity of peritoneal macrophages and splenocyte proliferation, and to inhibit nitric oxide (NO) production in macrophages. However, its potential impacts on immune response in dendritic cells (DCs), antigen-presenting cells that link innate and adaptive immunity, have yet to be clearly elucidated. In this study, we evaluated the effects of isoflavones on the maturation and activation of DCs. Isoflavones (formononetin, daidzein, equol, biochanin A, genistein) were found to differentially affect the expression of CD86, a costimulatory molecule, on lipopolysaccharide (LPS)-stimulated DCs. In particular, daidzein significantly and dose-dependently inhibited the expression levels of maturation-associated cell surface markers including CD40, costimulatory molecules (CD80, CD86), and major histocompatibility complex class II (I-A{sup b}) molecule on LPS-stimulated DCs. Daidzein also suppressed pro-inflammatory cytokine production such as IL-12p40, IL-6 and TNF-{alpha}, whereas it didn't affect IL-10 and IL-1{beta} expression. Furthermore, daidzein enhanced endocytosis and inhibited the allo-stimulatory ability of LPS-stimulated DCs on T cells, indicating that daidzein treatment can inhibit the functional maturation of DCs. These results demonstrate that daidzein may exhibit immunosuppressive activity by inhibiting the maturation and activation of DCs. -- Highlights: Black-Right-Pointing-Pointer Daidzein inhibited expression of maturation-associated cell surface markers in DCs. Black-Right-Pointing-Pointer Daidzein suppressed expression

Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women

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Veronika A. Myasoedova

2016-08-01

Full Text Available The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6 were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011 and by 5.2% in placebo recipients (p = 0.020; low density lipoprotein (LDL cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040 and by 5.2% in placebo recipients (non-significant, NS; high density lipoprotein (HDL cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS and by 4.5% in placebo recipients (p = 0.038; triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS and by

Phytoestrogens/insoluble fibers and colonic estrogen receptor β: Randomized, double-blind, placebo-controlled study

Science.gov (United States)

Principi, Mariabeatrice; Di Leo, Alfredo; Pricci, Maria; Scavo, Maria Principia; Guido, Raffaella; Tanzi, Sabina; Piscitelli, Domenico; Pisani, Antonio; Ierardi, Enzo; Comelli, Maria Cristina; Barone, Michele

2013-01-01

AIM: To assess the safety and effect of the supplementation of a patented blend of dietary phytoestrogens and insoluble fibers on estrogen receptor (ER)-β and biological parameters in sporadic colonic adenomas. METHODS: A randomized, double-blind placebo-controlled trial was performed. Patients scheduled to undergo surveillance colonoscopy for previous sporadic colonic adenomas were identified, and 60 eligible patients were randomized to placebo or active dietary intervention (ADI) twice a day, for 60 d before surveillance colonoscopy. ADI was a mixture of 175 mg milk thistle extract, 20 mg secoisolariciresinol and 750 mg oat fiber extract. ER-β and ER-α expression, apoptosis and proliferation (Ki-67 LI) were assessed in colon samples. RESULTS: No adverse event related to ADI was recorded. ADI administration showed a significant increases in ER-β protein (0.822 ± 0.08 vs 0.768 ± 0.10, P = 0.04) and a general trend to an increase in ER-β LI (39.222 ± 2.69 vs 37.708 ± 5.31, P = 0.06), ER-β/ER-α LI ratio (6.564 ± 10.04 vs 2.437 ± 1.53, P = 0.06), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (35.592 ± 14.97 vs 31.541 ± 11.54, P = 0.07) and Ki-67 (53.923 ± 20.91 vs 44.833 ± 10.38, P = 0.07) approximating statistical significance. A significant increase of ER-β protein (0.805 ± 0.13 vs 0.773 ± 0.13, P = 0.04), mRNA (2.278 ± 1.19 vs 1.105 ± 1.07, P < 0.02) and LI (47.533 ± 15.47 vs 34.875 ± 16.67, P < 0.05) and a decrease of ER-α protein (0.423 ± 0.06 vs 0.532 ± 0.11, P < 0.02) as well as a trend to increase of ER-β/ER-α protein in ADI vs placebo group were observed in patients without polyps (1.734 ± 0.20 vs 1.571 ± 0.42, P = 0.07). CONCLUSION: The role of ER-β on the control of apoptosis, and its amenability to dietary intervention, are supported in our study. PMID:23885143

Bidirectional regulation of bakuchiol, an estrogenic-like compound, on catecholamine secretion

International Nuclear Information System (INIS)

Mao, Haoping; Wang, Hong; Ma, Shangwei; Xu, Yantong; Zhang, Han; Wang, Yuefei; Niu, Zichang; Fan, Guanwei; Zhu, Yan; Gao, Xiu Mei

2014-01-01

Excess or deficiency of catecholamine (CA) secretion was related with several diseases. Recently, estrogen and phytoestrogens were reported to regulate the activity of CA system. Bakuchiol is a phytoestrogen isolated from the seeds of Psoralea corylifolia L. (Leguminosae) which has been used in Traditional Chinese medicine as a tonic or aphrodisiac. In the present study, bovine adrenal medullary cells were employed to investigate the effects and mechanisms of bakuchiol on the regulation of CA secretion. Further, its anti-depressant like and anti-stress effects were evaluated by using behavioral despair and chronic immobilization stress models. Our results indicated that bakuchiol showed bidirectional regulation on CA secretion. It stimulated basal CA secretion in a concentration dependent manner (p + (p + induced CA secretion was related with reduction of intracellular calcium rise. In vivo experiments, we found that bakuchiol significantly reduced immobilization time in behavioral despair mouse (p < 0.05 or 0.01), and plasma epinephrine (E) and norepinephrine (NE) levels in chronic immobilization stress (p < 0.05). Overall, these results present a bidirectional regulation of bakuchiol on CA secretion which indicated that bakuchiol may exert anti-stress and the potential anti-depressant-like effects. - Highlights: • Bakuchiol stimulated basal catecholamine secretion. • Bakuchiol inhibited various secretagogues induced catecholamine secretion. • Bakuchiol may have anti-stress and the potential anti-depression-like effects

The effect of the phytoestrogen genistein on myocardial protection, preconditioning and oxidative stress.

Science.gov (United States)

Sbarouni, Eftihia; Iliodromitis, Efstathios K; Zoga, Anastasia; Vlachou, Georgia; Andreadou, Ioanna; Kremastinos, Dimitrios Th

2006-08-01

We have previously shown that estrogen administered in ovariectomized female rabbits significantly reduce myocardial infarct size. We now investigated whether the phytoestrogen genistein similarly protects ischemic myocardium and whether this is associated with its antioxidant properties. In addition, we examined whether genistein abolishes preconditioning, since at high doses, it inhibits tyrosine kinase. We studied five groups of New Zealand white female rabbits. Group A (n = 12) were normal controls, group B (n = 14) were ovariectomized 4 weeks prior to the experiment, group C (n = 10) were ovariectomized and treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment, group D (n = 12) had intact gonads and were treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment and group E (n = 8) were ovariectomized 4 weeks prior to the experiment and treated with a single dose of genistein (0.2 mg kg(-1) day(-1) subcutaneously) just prior to the experiment. All animals underwent 30 min of heart ischemia and 120 min of reperfusion, with (subgroup I) or without (subgroup II) preconditioning. Malondialdehyde (MDA) concentration just before the experiment was determined. We found significant differences between the groups-p protect ischemic myocardium in either ovariectomized or non-ovariectomized animals-BII vs CII and AII vs DII, p = NS. There was no significant difference between the preconditioned animals, with intact gonads or ovariectomized (AI vs BI, p = NS), ovariectomized with or without genistein (BI vs CI, p = NS) and non-ovariectomized whether treated with genistein or not (AI vs DI, p = NS). A single dose of genistein did not offer any protection (EII vs BII, p = NS), nor did it modify the preconditioning effect (EI vs BI, p = NS). We found no significant difference in MDA plasma levels between the groups. Genistein, at this dose, does not reduce infarct size per se nor abolishes the

A diet containing the soy phytoestrogen genistein causes infertility in female rats partially deficient in UDP glucuronyltransferase

International Nuclear Information System (INIS)

Seppen, Jurgen

2012-01-01

Soy beans contain genistein, a natural compound that has estrogenic effects because it binds the estrogen receptor with relatively high affinity. Genistein is therefore the most important environmental estrogen in the human diet. Detoxification of genistein is mediated through conjugation by UDP-glucuronyltransferase 1 and 2 (UGT1 and UGT2) isoenzymes. Gunn rats have a genetic deficiency in UGT1 activity, UGT2 activities are not affected. Because our Gunn rats stopped breeding after the animal chow was changed to a type with much higher soy content, we examined the mechanism behind this soy diet induced infertility. Gunn and control rats were fed diets with and without genistein. In these rats, plasma levels of genistein and metabolites, fertility and reproductive parameters were determined. Enzyme assays showed reduced genistein UGT activity in Gunn rats, as compared to wild type rats. Female Gunn rats were completely infertile on a genistein diet, wild type rats were fertile. Genistein diet caused a persistent estrus, lowered serum progesterone and inhibited development of corpora lutea in Gunn rats. Concentrations of total genistein in Gunn and control rat plasma were identical and within the range observed in humans after soy consumption. However, Gunn rat plasma contained 25% unconjugated genistein, compared to 3.6% in control rats. This study shows that, under conditions of reduced glucuronidation, dietary genistein exhibits a strongly increased estrogenic effect. Because polymorphisms that reduce UGT1 expression are prevalent in the human population, these results suggest a cautionary attitude towards the consumption of large amounts of soy or soy supplements. -- Highlights: ► Gunn rats are partially deficient in detoxification by UDP glucuronyltransferases. ► Female Gunn rats are infertile on a soy containing diet. ► Soy contains genistein, a potent phytoestrogen. ► Inefficient glucuronidation of genistein causes female infertility.

A diet containing the soy phytoestrogen genistein causes infertility in female rats partially deficient in UDP glucuronyltransferase

Energy Technology Data Exchange (ETDEWEB)

Seppen, Jurgen, E-mail: j.seppen@amc.uva.nl

2012-11-01

Soy beans contain genistein, a natural compound that has estrogenic effects because it binds the estrogen receptor with relatively high affinity. Genistein is therefore the most important environmental estrogen in the human diet. Detoxification of genistein is mediated through conjugation by UDP-glucuronyltransferase 1 and 2 (UGT1 and UGT2) isoenzymes. Gunn rats have a genetic deficiency in UGT1 activity, UGT2 activities are not affected. Because our Gunn rats stopped breeding after the animal chow was changed to a type with much higher soy content, we examined the mechanism behind this soy diet induced infertility. Gunn and control rats were fed diets with and without genistein. In these rats, plasma levels of genistein and metabolites, fertility and reproductive parameters were determined. Enzyme assays showed reduced genistein UGT activity in Gunn rats, as compared to wild type rats. Female Gunn rats were completely infertile on a genistein diet, wild type rats were fertile. Genistein diet caused a persistent estrus, lowered serum progesterone and inhibited development of corpora lutea in Gunn rats. Concentrations of total genistein in Gunn and control rat plasma were identical and within the range observed in humans after soy consumption. However, Gunn rat plasma contained 25% unconjugated genistein, compared to 3.6% in control rats. This study shows that, under conditions of reduced glucuronidation, dietary genistein exhibits a strongly increased estrogenic effect. Because polymorphisms that reduce UGT1 expression are prevalent in the human population, these results suggest a cautionary attitude towards the consumption of large amounts of soy or soy supplements. -- Highlights: ► Gunn rats are partially deficient in detoxification by UDP glucuronyltransferases. ► Female Gunn rats are infertile on a soy containing diet. ► Soy contains genistein, a potent phytoestrogen. ► Inefficient glucuronidation of genistein causes female infertility.

Changes in the biochemical composition of testes during spermatogenesis in Asterias vulgaris, with emphasis on the role of polyamines in regulating proliferation

International Nuclear Information System (INIS)

Smith, F.F.

1985-01-01

Testes of Asterias vulgaris are potentially useful for investigating mechanisms regulating spermatogenic events because of their structural simplicity and annual spermatogenic cycle. Examination of major biochemical classes during the spermatogenic cycle provides a definition of the changing chemical microenvironment influencing germinal cells and also suggests temporal relationships among successive spermatogenic events. Testes from seastars collected throughout the year were homogenized and lyophilized and aliquots assayed for DNA, RNA, total protein, free amino acids, total lipids, glycogen, and other carbohydrates; spermatogenic stage was determined by examination of paraffin sections. Activity of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine synthesis, increases during the proliferative phase of spermatogenesis. Testicular ODC activity correlates well with DNA synthetic rate. To test the possible role of polyamines in regulating initiation of spermatogonial mitoses, intact testes near the beginning of the proliferative phase were incubated in vitro with exogenous polyamines. They subsequently showed a significant increase in incorporation of 3 H-thymidine into DNA. These results suggest a direct role for polyamines in the regulation of spermatogenic proliferation in a. vulgaris. Evidence for a regulatory role of polyamines in the initiation of proliferation, together with existing information on the environmental, hormonal, and cytological interactions, facilitates development of a preliminary model for regulation and entrainment of spermatogenesis

Prescription profile of Chinese herbal products containing coumestrol, genestein, and/or daidzein among female users: an analysis of national health insurance data in Taiwan between 1997 and 2007.

Science.gov (United States)

Wu, Chien-Tung; Tzeng, Jeng-Nan; Lai, Jung-Nien; Tsan, Shun-Hua; Wang, Jung-Der

2012-10-16

Some Chinese herbs contain several kinds of phytoestrogens, and these herbs are commonly prescribed in Taiwan. Phytoestrogens may influence the effects of estrogen in females, although their activities are weak. This study aims to identify the risk and analyze the prescription profile of commonly used phytoestrogenic herbs in Taiwan. The study analyzed women who had been prescribed phytoestrogenic herbs including coumestrol, genistein and/or daidzein between 1997 and 2007 in a fixed cohort taken from all female beneficiaries from the National Health Insurance Research Database of Taiwan. The prescription frequencies, cumulated dosages, and primary indications were listed. A total of 462,861 women were included in the study, of whom ~47.0% had used phytoestrogenic herbs at least once during the study period. A total of 6,270,813 prescriptions were recorded, and more than 20% of these contained phytoestrogens. The most commonly prescribed herb and formula were Puerariae Radix and Ge gen tang (Pueraria Decoction), respectively. Most of the prescriptions were issued for diseases of the respiratory system, followed by symptoms, signs, and ill-defined conditions and diseases of the musculoskeletal system and connective tissue. This study shows that women who sought medical treatment from Chinese medicine doctors for relief of respiratory discomfort had a high possibility of exposure to phytoestrogenic herbs. Safety issues related to the female endocrine system should be a priority for future research.

Analysis of the interaction of phytoestrogens and synthetic chemicals: An in vitro/in vivo comparison

International Nuclear Information System (INIS)

Charles, Grantley D.; Gennings, Chris; Tornesi, Belen; Kan, H. Lynn; Zacharewski, Timothy R.; Bhaskar Gollapudi, B.; Carney, Edward W.

2007-01-01

In the evaluation of chemical mixture toxicity, it is desirable to develop an evaluation paradigm which incorporates some critical attributes of real world exposures, particularly low dose levels, larger numbers of chemicals, and chemicals from synthetic and natural sources. This study evaluated the impact of low level exposure to a mixture of six synthetic chemicals (SC) under conditions of co-exposure to various levels of plant-derived phytoestrogen (PE) compounds. Estrogenic activity was evaluated using an in vitro human estrogen receptor (ER) transcriptional activation assay and an in vivo immature rat uterotrophic assay. Initially, dose-response curves were characterized for each of the six SCs (methoxyclor, o,p-DDT, octylphenol, bisphenol A, β-hexachlorocyclohexane, 2,3-bis(4-hydroxyphenyl)-propionitrile) in each of the assays. The six SCs were then combined at equipotent ratios and tested at 5-6 dose levels spanning from very low, sub-threshold levels, to a dose in which every chemical in the mixture was at its individual estrogenic response threshold. The SC mixtures also were tested in the absence or presence of 5-6 different levels of PEs, for a total of 36 (in vitro) or 25 (in vivo) treatment groups. Both in vitro and in vivo, low concentrations of the SC mixture failed to increase estrogenic responses relative to those induced by PEs alone. However, significant increases in response occurred when each chemical in the SC mixture was near or above its individual response threshold. In vitro, interactions between high-doses of SCs and PEs were greater than additive, whereas mixtures of SCs in the absence of PEs interacted in a less than additive fashion. In vivo, the SC and PE mixture responses were consistent with additivity. These data illustrate a novel approach for incorporating key attributes of real world exposures in chemical mixture toxicity assessments, and suggest that chemical mixture toxicity is likely to be of concern only when the mixture

Prescription profile of Chinese herbal products containing coumestrol, genestein, and/or daidzein among female users: an analysis of national health insurance data in Taiwan between 1997 and 2007

Directory of Open Access Journals (Sweden)

Wu Chien-Tung

2012-10-01

Full Text Available Abstract Background Some Chinese herbs contain several kinds of phytoestrogens, and these herbs are commonly prescribed in Taiwan. Phytoestrogens may influence the effects of estrogen in females, although their activities are weak. This study aims to identify the risk and analyze the prescription profile of commonly used phytoestrogenic herbs in Taiwan. Methods The study analyzed women who had been prescribed phytoestrogenic herbs including coumestrol, genistein and/or daidzein between 1997 and 2007 in a fixed cohort taken from all female beneficiaries from the National Health Insurance Research Database of Taiwan. The prescription frequencies, cumulated dosages, and primary indications were listed. Results A total of 462,861 women were included in the study, of whom ~47.0% had used phytoestrogenic herbs at least once during the study period. A total of 6,270,813 prescriptions were recorded, and more than 20% of these contained phytoestrogens. The most commonly prescribed herb and formula were Puerariae Radix and Ge gen tang (Pueraria Decoction, respectively. Most of the prescriptions were issued for diseases of the respiratory system, followed by symptoms, signs, and ill-defined conditions and diseases of the musculoskeletal system and connective tissue. Conclusion This study shows that women who sought medical treatment from Chinese medicine doctors for relief of respiratory discomfort had a high possibility of exposure to phytoestrogenic herbs. Safety issues related to the female endocrine system should be a priority for future research.

In-vitro secretion of inhibin-like activity by Sertoli cells from normal and prenatally irradiated immature rats

International Nuclear Information System (INIS)

Ultee-van Gessel, A.M.; Leemborg, F.G.; Jong, F.H. de; Molen, H.J. van der

1986-01-01

The influence of in-vitro conditions on the production of inhibin by Sertoli cells from 21-day-old normal and prenatally irradiated rat testes was studied by measuring inhibin activity in culture media, using the suppression of the release of FSH from cultured rat pituitary cells. Sertoli cells secreted inhibin-like activity during at least 21 days of culture, and cells cultured at 37 0 C produced significantly more inhibin than those cultured at 32 0 C. The presence of fetal calf serum had no significant effect on inhibin production at 32 0 C, while at 37 0 C the production was decreased. The presence of ovine FSH stimulated inhibin secretion, while inhibin concentrations in Sertoli cell culture media were decreased after the addition of testosterone. Testosterone, added together with ovine FSH, suppressed inhibin secretion when compared with the levels found in the presence of FSH alone. The presence of spermatogenic cells decreased the release of inhibin. From these results it was concluded that both Sertoli cells isolated from normal immature rat testes and those from testes without spermatogenic cells can secrete inhibin-like activity in culture. A number of discrepancies with in-vivo observations was observed. (author)

Brain Stimulation Therapies

Science.gov (United States)

... Magnetic Seizure Therapy Deep Brain Stimulation Additional Resources Brain Stimulation Therapies Overview Brain stimulation therapies can play ... for a shorter recovery time than ECT Deep Brain Stimulation Deep brain stimulation (DBS) was first developed ...

The Effect of Hydro-alcoholic Extract of Leaves of Vitex on the Gestation Indices of Male Rats

OpenAIRE

Fereshteh Ramezanloo; Parvaneh Najafizadeh; Tahereh Naji; Gholamreza Amin; Zahra Mousavi; Gelareh Vahabzadeh

2017-01-01

Background: Phytoestrogens are some plant compounds with estrogenic biological effects which are found in many nutritional sources as soybean, flaxseed, and sesame. Vitex agnus-castus, also called Vitex, owns phytoestrogen properties. Studies have shown that phytoestrogens have different impacts on the gestation process and reproduction indices. Objective: The present study was aimed to investigate the effects of Vitex extract on the gestation indices in the male rat as well as studyin...

Computationally Developed Sham Stimulation Protocol for Multichannel Desynchronizing Stimulation

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Magteld Zeitler

2018-05-01

Full Text Available A characteristic pattern of abnormal brain activity is abnormally strong neuronal synchronization, as found in several brain disorders, such as tinnitus, Parkinson's disease, and epilepsy. As observed in several diseases, different therapeutic interventions may induce a placebo effect that may be strong and hinder reliable clinical evaluations. Hence, to distinguish between specific, neuromodulation-induced effects and unspecific, placebo effects, it is important to mimic the therapeutic procedure as precisely as possibly, thereby providing controls that actually lack specific effects. Coordinated Reset (CR stimulation has been developed to specifically counteract abnormally strong synchronization by desynchronization. CR is a spatio-temporally patterned multichannel stimulation which reduces the extent of coincident neuronal activity and aims at an anti-kindling, i.e., an unlearning of both synaptic connectivity and neuronal synchrony. Apart from acute desynchronizing effects, CR may cause sustained, long-lasting desynchronizing effects, as already demonstrated in pre-clinical and clinical proof of concept studies. In this computational study, we set out to computationally develop a sham stimulation protocol for multichannel desynchronizing stimulation. To this end, we compare acute effects and long-lasting effects of six different spatio-temporally patterned stimulation protocols, including three variants of CR, using a no-stimulation condition as additional control. This is to provide an inventory of different stimulation algorithms with similar fundamental stimulation parameters (e.g., mean stimulation rates but qualitatively different acute and/or long-lasting effects. Stimulation protocols sharing basic parameters, but inducing nevertheless completely different or even no acute effects and/or after-effects, might serve as controls to validate the specific effects of particular desynchronizing protocols such as CR. In particular, based on

The anti-metastatic effects of the phytoestrogen arctigenin on human breast cancer cell lines regardless of the status of ER expression.

Science.gov (United States)

Maxwell, Thressi; Chun, So-Young; Lee, Kyu-Shik; Kim, Soyoung; Nam, Kyung-Soo

2017-02-01

Arctigenin is a plant lignan extracted from Arctium lappa that has been shown to have estrogenic properties. In spite of the health benefits of phytoestrogens reducing the risk of osteoporosis, heart disease, and menopausal symptoms, its benefits against the risk of breast cancer have not been fully elucidated. Thus, we investigated the effects of arctigenin on metastasis of breast cancer using both estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cell lines to see if the effects are dependent on the status of ER expression. In ER-positive MCF-7 cells, arctigenin efficiently inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration and invasion. The activity of crucial metastatic protease matrix metalloprotease (MMP)-9 in gelatin zymography was also efficiently decreased by arctigenin, as well as its mRNA expression. Notably, arctigenin exhibited similar anti-metastatic effects even in ER-negative MDA-MB-231 cells, suggesting that the anti-metastatic effects of arctigenin were not exerted via the ER. The upstream signaling pathways involved in the regulation of MMP-9 and urokinase plasminogen activator (uPA) were analyzed using western blotting. The activation of Akt, NF-κB and MAPK (ERK 1/2 and JNK 1/2) was found to be inhibited. Taken together, these data suggest that arctigenin confers anti-metastatic effects by inhibiting MMP-9 and uPA via the Akt, NF-κB and MAPK signaling pathways on breast cancer, regardless of ER expression. Therefore, we propose that the intake of arctigenin could be an effective supplement for breast cancer patients.

Red wine consumption may affect sperm biology: the effects of different concentrations of the phytoestrogen myricetin on human male gamete function.

Science.gov (United States)

Aquila, Saveria; Santoro, Marta; De Amicis, Francesca; Guido, Carmela; Bonofiglio, Daniela; Lanzino, Marilena; Cesario, Maria Grazia; Perrotta, Ida; Sisci, Diego; Morelli, Catia

2013-02-01

Myricetin is a natural flavonoid, particularly enriched in red wines, whose occurrence is widespread among plants. Despite extensive research, the beneficial effects of Myricetin on human health are still controversial. Here, we tested the estrogen-like effect of the phytoestrogen Myricetin on human ejaculated sperm biology. To this aim, human normozoospermic samples were exposed to increasing concentrations (10 nM, 100 nM, and 1 µM) of Myricetin. Motility, viability, capacitation-associated biochemical changes (i.e., cholesterol efflux and tyrosine phosphorylation), acrosin activity, as well as glucose utilization and fatty-acid oxidation (i.e., glucose and lipid metabolism) were all significantly increased by low doses of Myricetin. Importantly, both estrogen receptors α and β (ERs) and phosphatidylinositol-3-OH kinase (PI3K)/AKT signaling are activated in the presence of Myricetin since these were both abrogated by specific inhibitors of each pathway. Our results show how Myricetin, through ERs and PI3K/AKT signalings, potentiates sperm function. This effect is dose-dependent at low concentrations of Myricetin (up to 100 nM), whereas higher amounts do not seem to improve any further sperm motility, viability, or other tested features, and, in some cases, they reduced or even abrogated the efficacy exerted by lower doses. Further studies are needed to elucidate if high levels of Myricetin, which could be attained even with moderate wine consumption, could synergize with endogenous estrogens in the female reproductive tract, interfering with the physiological sperm fertilization process. Copyright © 2012 Wiley Periodicals, Inc.

Effects of phytoestrogen supplementation in the feed on the shell gland of laying hens at the end of the laying period.

Science.gov (United States)

Wistedt, A; Ridderstråle, Y; Wall, H; Holm, L

2012-08-01

Shell quality decreases as laying hens age and the aim of present study was to investigate how a supplement of daidzein, a natural phytoestrogen in soya, affects key factors in the shell gland and eggshell quality in late-stage laying hens. Hybrids of Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), received either a daidzein diet (50 mg/kg feed) or a control diet from 60 to 72 weeks of age. Both the total number of capillaries and capillaries with carbonic anhydrase (CA) activity were higher in the LSL hybrid than in the LB. After daidzein supplementation the number of CA positive capillaries was unaffected in the LSL but increased in the LB hybrid indicating a higher sensitivity to daidzein in this hybrid. Estrogen receptor alpha and beta (ERα, ERβ) were localized and the complete picture of the two ERs can now be described in shell gland of domestic hens. Nuclear and cytoplasmic staining was generally stronger for ERβ, while membrane associated staining was present only for ERα. Interestingly, capillary endothelium contained only ERβ and since estrogen regulation of CA is well documented, the presence of an endothelial ER provides one possible route for the increase in CA positive capillaries found in LB hybrids. Eggshell quality or egg production was not affected by daidzein supplementation. The hybrids used in this study showed anatomical differences and reacted differently to daidzein supplementation, but if this can be explained by the divergences in ERβ localization noted between the hybrids remains to be clarified. Copyright © 2012 Elsevier B.V. All rights reserved.

Kaempferol, a phytoestrogen, suppressed triclosan-induced epithelial-mesenchymal transition and metastatic-related behaviors of MCF-7 breast cancer cells.

Science.gov (United States)

Lee, Geum-A; Choi, Kyung-Chul; Hwang, Kyung-A

2017-01-01

As a phytoestrogen, kaempferol is known to play a chemopreventive role inhibiting carcinogenesis and cancer progression. In this study, the influences of triclosan, an anti-bacterial agent recently known for an endocrine disrupting chemical (EDC), and kaempferol on breast cancer progression were examined by measuring their effects on epithelial-mesenchymal transition (EMT) and metastatic-related behaviors of MCF-7 breast cancer cells. Morphological changes of MCF-7 cells were observed, and a wound-healing assay was performed after the treatment of triclosan and kaempferol. The effects of triclosan and kaempferol on protein expression of EMT-related markers such as E-cadherin, N-cadherin, Snail, and Slug and metastasis-related markers such as cathepsin B, D, MMP-2 and -9 were investigated by Western blot assay. In microscopic observations, triclosan (10 -6 M) or E2 (10 -9 M) induced transition to mesenchymal phenotype of MCF-7 cells compared with the control. Co-treatment of ICI 182,780 (10 -8 M), an ER antagonist, or kaempferol (25μM) with E2 or triclosan restored the cellular morphology to an epithelial phenotype. In a wound-healing scratch and a transwell migration assay, triclosan enhanced migration and invasion of MCF-7 cells, but co-treatment of kaempferol or ICI 182,780 reduced the migration and invasion ability of MCF-7 cells to the control level. In addition, kaempferol effectively suppressed E2 or triclosan-induced protein expressions of EMT and metastasis promoting markers. Taken together, triclosan may be a distinct xenoestrogenic EDC to promote EMT, migration, and invasion of MCF-7 breast cancer cells through ER. On the other hand, kaempferol can be an alternative chemopreventive agent to effectively suppress the metastatic behavior of breast cancer induced by an endogenous estrogen as well as exogenous xenoestrogenic compounds including triclosan. Copyright © 2016 Elsevier B.V. All rights reserved.

Genistein Stimulates Jejunum Chloride Secretion via an Akt-Mediated Pathway in Intact Female Mice

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Lana Leung

2015-02-01

Full Text Available Background/Aims: We have previously shown that daily subcutaneous injections with the naturally occurring phytoestrogen genistein (600 mg genistein/kg body weight/day, 600G results in a significantly increased basal intestinal chloride, Cl-, secretion (Isc, a measure of transepithelial secretion in intact C57BL/6J female mice after 1-week of treatment, compared to controls (DMSO vehicle injected. Removal of endogenous estrogen via ovariectomy (OVX had no effect on the 600G-mediated increase in basal Isc. Methods: Given the estrogen-like characteristics of genistein, we compared the effects of daily estradiol (E2 injections (10 mg E2/kg body weight/day, 10E2 on basal Isc in intact and OVX mice. In intact mice, 10E2 was without effect on basal Isc, however, in OVX mice, 10E2 significantly increased basal Isc (mimicked 600G. The goal of the current study was to characterize the intracellular signaling pathways responsible for mediating 600G- or 10E2-stimulated increases in basal Isc in intact female or OVX mice. Results: We measured total protein expression in isolated segments of jejunum using western blot from the following six groups of mice; intact or OVX with; 600G, 10E2 or control. The proteins of interest were: Akt, p-Akt, p-PDK1, p-PTEN, p-c-Raf, p-GSK-3β, rap-1 and ERK1/2. All blots were normalized to GAPDH levels (n = 6-18/group. Conclusion: These data suggest that the presence of the endogenous sex steroid, estrogen, modifies the intracellular signaling pathway required to mediate Cl- secretion when the intestine is exposed to exogenous 600G or E2. These studies may have relevance for designing pharmacological tools for women with intestinal chloride secretory dysfunctions.

Towards a Switched-Capacitor Based Stimulator for Efficient Deep-Brain Stimulation

Science.gov (United States)

Vidal, Jose; Ghovanloo, Maysam

2013-01-01

We have developed a novel 4-channel prototype stimulation circuit for implantable neurological stimulators (INS). This Switched-Capacitor based Stimulator (SCS) aims to utilize charge storage and charge injection techniques to take advantage of both the efficiency of conventional voltage-controlled stimulators (VCS) and the safety and controllability of current-controlled stimulators (CCS). The discrete SCS prototype offers fine control over stimulation parameters such as voltage, current, pulse width, frequency, and active electrode channel via a LabVIEW graphical user interface (GUI) when connected to a PC through USB. Furthermore, the prototype utilizes a floating current sensor to provide charge-balanced biphasic stimulation and ensure safety. The stimulator was analyzed using an electrode-electrolyte interface (EEI) model as well as with a pair of pacing electrodes in saline. The primary motivation of this research is to test the feasibility and functionality of a safe, effective, and power-efficient switched-capacitor based stimulator for use in Deep Brain Stimulation. PMID:21095987

Ultrasound stimulation on bone healing. The optimization of stimulation time

International Nuclear Information System (INIS)

Rosim, R.C.; Paulin, J.B.P.; Goncalves, R.P.

1990-01-01

Previous works in ultrasonic simulation of bone healing dealt with parameters optimization. Albertin (1983) studied the stimulation time and found forty minutes as ideal. However, this stimulation time was the largest one employed and remained some doubt about the most appropriated value. 30, 40, 50 and 60 minutes of stimulation time were selected, while others parameters were held constant with: pulse width in 200 μs, repetition rate in 1000 pulses per second and amplitude in 30 V. Partial incomplete transverse osteotomies were done in the middle third of radio in the right forearm of rabbits. Twenty four animals divided in four subgroups, with 6 animals each were stimulated. The daily stimulation time for each subgroup was 30, 40, 50 and minutes respectively, during 15 consecutive days. The stimulation procedure started 24 hours after surgery. After the stimulation period, radiological, histological and morphometric evaluations were done and greater bone healing was found for the 50 minutes stimulation subgroup, in them new bone was also prominent. (author)

Stimulating at the right time: phase-specific deep brain stimulation.

Science.gov (United States)

Cagnan, Hayriye; Pedrosa, David; Little, Simon; Pogosyan, Alek; Cheeran, Binith; Aziz, Tipu; Green, Alexander; Fitzgerald, James; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Friston, Karl J; Denison, Timothy; Brown, Peter

2017-01-01

SEE MOLL AND ENGEL DOI101093/AWW308 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Brain regions dynamically engage and disengage with one another to execute everyday actions from movement to decision making. Pathologies such as Parkinson's disease and tremor emerge when brain regions controlling movement cannot readily decouple, compromising motor function. Here, we propose a novel stimulation strategy that selectively regulates neural synchrony through phase-specific stimulation. We demonstrate for the first time the therapeutic potential of such a stimulation strategy for the treatment of patients with pathological tremor. Symptom suppression is achieved by delivering stimulation to the ventrolateral thalamus, timed according to the patient's tremor rhythm. Sustained locking of deep brain stimulation to a particular phase of tremor afforded clinically significant tremor relief (up to 87% tremor suppression) in selected patients with essential tremor despite delivering less than half the energy of conventional high frequency stimulation. Phase-specific stimulation efficacy depended on the resonant characteristics of the underlying tremor network. Selective regulation of neural synchrony through phase-locked stimulation has the potential to both increase the efficiency of therapy and to minimize stimulation-induced side effects. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain.

[Transcranial magnetic stimulation and motor cortex stimulation in neuropathic pain].

Science.gov (United States)

Mylius, V; Ayache, S S; Teepker, M; Kappus, C; Kolodziej, M; Rosenow, F; Nimsky, C; Oertel, W H; Lefaucheur, J P

2012-12-01

Non-invasive and invasive cortical stimulation allows the modulation of therapy-refractory neuropathic pain. High-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralateral motor cortex yields therapeutic effects at short-term and predicts the benefits of epidural motor cortex stimulation (MCS). The present article summarizes the findings on application, mechanisms and therapeutic effects of cortical stimulation in neuropathic pain.

Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

Science.gov (United States)

Zhou, Hui; Lu, Yi; Chen, Wanzhen; Wu, Zhen; Zou, Haiqing; Krundel, Ludovic; Li, Guanglin

2015-01-01

Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes. PMID:26193273

Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

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Hui Zhou

2015-07-01

Full Text Available Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes.

Biomarkers and Stimulation Algorithms for Adaptive Brain Stimulation

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Kimberly B. Hoang

2017-10-01

Full Text Available The goal of this review is to describe in what ways feedback or adaptive stimulation may be delivered and adjusted based on relevant biomarkers. Specific treatment mechanisms underlying therapeutic brain stimulation remain unclear, in spite of the demonstrated efficacy in a number of nervous system diseases. Brain stimulation appears to exert widespread influence over specific neural networks that are relevant to specific disease entities. In awake patients, activation or suppression of these neural networks can be assessed by either symptom alleviation (i.e., tremor, rigidity, seizures or physiological criteria, which may be predictive of expected symptomatic treatment. Secondary verification of network activation through specific biomarkers that are linked to symptomatic disease improvement may be useful for several reasons. For example, these biomarkers could aid optimal intraoperative localization, possibly improve efficacy or efficiency (i.e., reduced power needs, and provide long-term adaptive automatic adjustment of stimulation parameters. Possible biomarkers for use in portable or implanted devices span from ongoing physiological brain activity, evoked local field potentials (LFPs, and intermittent pathological activity, to wearable devices, biochemical, blood flow, optical, or magnetic resonance imaging (MRI changes, temperature changes, or optogenetic signals. First, however, potential biomarkers must be correlated directly with symptom or disease treatment and network activation. Although numerous biomarkers are under consideration for a variety of stimulation indications the feasibility of these approaches has yet to be fully determined. Particularly, there are critical questions whether the use of adaptive systems can improve efficacy over continuous stimulation, facilitate adjustment of stimulation interventions and improve our understanding of the role of abnormal network function in disease mechanisms.

A distributed current stimulator ASIC for high density neural stimulation.

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Jeong Hoan Park; Chaebin Kim; Seung-Hee Ahn; Tae Mok Gwon; Joonsoo Jeong; Sang Beom Jun; Sung June Kim

2016-08-01

This paper presents a novel distributed neural stimulator scheme. Instead of a single stimulator ASIC in the package, multiple ASICs are embedded at each electrode site for stimulation with a high density electrode array. This distributed architecture enables the simplification of wiring between electrodes and stimulator ASIC that otherwise could become too complex as the number of electrode increases. The individual ASIC chip is designed to have a shared data bus that independently controls multiple stimulating channels. Therefore, the number of metal lines is determined by the distributed ASICs, not by the channel number. The function of current steering is also implemented within each ASIC in order to increase the effective number of channels via pseudo channel stimulation. Therefore, the chip area can be used more efficiently. The designed chip was fabricated with area of 0.3 mm2 using 0.18 μm BCDMOS process, and the bench-top test was also conducted to validate chip performance.

The safety and tolerance of phytotherapies in menopausal medicine – a review of the literature

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Piotr Czuczwar

2017-04-01

Full Text Available Phytoestrogens are polyphenol, non-steroidal substances of plant origin, resembling 17-estradiol in structure. These substances can act as either agonists or antagonists of oestrogen receptors  and . Phytoestrogens are widely used to alleviate menopausal symptoms, such as hot flushes and night sweats. Most of the currently available products of plant origin registered to soften climacteric symptoms consist of extracts obtained from soy, red clover, or black cohosh. Non-hormonal phytotherapy is a new alternative for patients suffering from menopausal symptoms. Active ingredients such as PI 82-GC FEM extract do not show any direct hormonal mechanisms of action typical for oestrogens and phytoestrogens. There are concerns about the safety and tolerability of phytoestrogens. In this review we summarise the current literature regarding the clinical aspect of safety and tolerance of different phytotherapies used to relieve menopausal symptoms.

Transcranial brain stimulation: closing the loop between brain and stimulation

DEFF Research Database (Denmark)

Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

2016-01-01

-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified......PURPOSE OF REVIEW: To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS: Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain...... stimulation. Trait-related and state-related determinants contribute to this variability, challenging the standard approach to apply stimulation in a rigid, one-size-fits-all fashion. Several strategies have been identified to reduce variability and maximize the plasticity-inducing effects of noninvasive...

Vagal nerve stimulation therapy: what is being stimulated?

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Kember, Guy; Ardell, Jeffrey L; Armour, John A; Zamir, Mair

2014-01-01

Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity.

Vagal nerve stimulation therapy: what is being stimulated?

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Guy Kember

Full Text Available Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity.

A novel dual-wavelength laser stimulator to elicit transient and tonic nociceptive stimulation.

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Dong, Xiaoxi; Liu, Tianjun; Wang, Han; Yang, Jichun; Chen, Zhuying; Hu, Yong; Li, Yingxin

2017-07-01

This study aimed to develop a new laser stimulator to elicit both transient and sustained heat stimulation with a dual-wavelength laser system as a tool for the investigation of both transient and tonic experimental models of pain. The laser stimulator used a 980-nm pulsed laser to generate transient heat stimulation and a 1940-nm continuous-wave (CW) laser to provide sustained heat stimulation. The laser with 980-nm wavelength can elicit transient pain with less thermal injury, while the 1940-nm CW laser can effectively stimulate both superficial and deep nociceptors to elicit tonic pain. A proportional integral-derivative (PID) temperature feedback control system was implemented to ensure constancy of temperature during heat stimulation. The performance of this stimulator was evaluated by in vitro and in vivo animal experiments. In vitro experiments on totally 120 specimens fresh pig skin included transient heat stimulation by 980-nm laser (1.5 J, 10 ms), sustained heat stimulation by 1940-nm laser (50-55 °C temperature control mode or 1.5 W, 5 min continuous power supply), and the combination of transient/sustained heat stimulation by dual lasers (1.5 J, 10 ms, 980-nm pulse laser, and 1940-nm laser with 50-55 °C temperature control mode). Hemoglobin brushing and wind-cooling methods were tested to find better stimulation model. A classic tail-flick latency (TFL) experiment with 20 Wistar rats was used to evaluate the in vivo efficacy of transient and tonic pain stimulation with 15 J, 100 ms 980-nm single laser pulse, and 1.5 W constant 1940-nm laser power. Ideal stimulation parameters to generate transient pain were found to be a 26.6 °C peak temperature rise and 0.67 s pain duration. In our model of tonic pain, 5 min of tonic stimulation produced a temperature change of 53.7 ± 1.3 °C with 1.6 ± 0.2% variation. When the transient and tonic stimulation protocols were combined, no significant difference was observed depending on the order

Cognitive stimulation in healthy older adults: a cognitive stimulation program using leisure activities compared to a conventional cognitive stimulation program.

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Grimaud, Élisabeth; Taconnat, Laurence; Clarys, David

2017-06-01

The aim of this study was to compare two methods of cognitive stimulation for the cognitive functions. The first method used an usual approach, the second used leisure activities in order to assess their benefits on cognitive functions (speed of processing; working memory capacity and executive functions) and psychoaffective measures (memory span and self esteem). 67 participants over 60 years old took part in the experiment. They were divided into three groups: 1 group followed a program of conventional cognitive stimulation, 1 group a program of cognitive stimulation using leisure activities and 1 control group. The different measures have been evaluated before and after the training program. Results show that the cognitive stimulation program using leisure activities is as effective on memory span, updating and memory self-perception as the program using conventional cognitive stimulation, and more effective on self-esteem than the conventional program. There is no difference between the two stimulated groups and the control group on speed of processing. Neither of the two cognitive stimulation programs provides a benefit over shifting and inhibition. These results indicate that it seems to be possible to enhance working memory and to observe far transfer benefits over self-perception (self-esteem and memory self-perception) when using leisure activities as a tool for cognitive stimulation.

Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract)

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Ueno, S.; Matsuda, T.

1991-04-01

We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.

Bidirectional regulation of bakuchiol, an estrogenic-like compound, on catecholamine secretion

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Mao, Haoping; Wang, Hong; Ma, Shangwei; Xu, Yantong; Zhang, Han; Wang, Yuefei [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China); Niu, Zichang [First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin (China); Fan, Guanwei; Zhu, Yan [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China); Gao, Xiu Mei, E-mail: gaoxiumei@tjutcm.edu.cn [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China)

2014-01-01

Excess or deficiency of catecholamine (CA) secretion was related with several diseases. Recently, estrogen and phytoestrogens were reported to regulate the activity of CA system. Bakuchiol is a phytoestrogen isolated from the seeds of Psoralea corylifolia L. (Leguminosae) which has been used in Traditional Chinese medicine as a tonic or aphrodisiac. In the present study, bovine adrenal medullary cells were employed to investigate the effects and mechanisms of bakuchiol on the regulation of CA secretion. Further, its anti-depressant like and anti-stress effects were evaluated by using behavioral despair and chronic immobilization stress models. Our results indicated that bakuchiol showed bidirectional regulation on CA secretion. It stimulated basal CA secretion in a concentration dependent manner (p < 0.01), while it reduced 300 μM acetylcholine (ACh) (p < 0.01), 100 μM veratridine (Ver) (p < 0.01) and 56 mM K{sup +} (p < 0.05) induced CA secretion, respectively. We also found that the stimulation of basal CA secretion by bakuchiol may act through estrogen-like effect and the JNK pathway in an extra-cellular calcium independent manner. Further, bakuchiol elevated tyrosine hydroxylase Ser40 and Ser31 phosphorylation (p < 0.01) through the PKA and ERK1/2 pathways, respectively. Bakuchiol inhibited ACh, Ver and 56 mM K{sup +} induced CA secretion was related with reduction of intracellular calcium rise. In vivo experiments, we found that bakuchiol significantly reduced immobilization time in behavioral despair mouse (p < 0.05 or 0.01), and plasma epinephrine (E) and norepinephrine (NE) levels in chronic immobilization stress (p < 0.05). Overall, these results present a bidirectional regulation of bakuchiol on CA secretion which indicated that bakuchiol may exert anti-stress and the potential anti-depressant-like effects. - Highlights: • Bakuchiol stimulated basal catecholamine secretion. • Bakuchiol inhibited various secretagogues induced catecholamine secretion

[Transcranial magnetic stimulation].

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Tormos, J M; Catalá, M D; Pascual-Leone, A

Transcranial magnetic stimulation (TMS) permits stimulation of the cerebral cortex in humans without requiring open access to the brain and is one of the newest tools available in neuroscience. There are two main types of application: single-pulse TMS and repetitive TMS. The magnetic stimulator is composed of a series of capacitors that store the voltage necessary to generate a stimulus of the sufficient intensity of generate an electric field in the stimulation coil. The safety of TMS is supported by the considerable experience derived from studies involving electrical stimulation of the cortex in animals and humans, and also specific studies on the safety of TMS in humans. In this article we review historical and technical aspects of TMS, describe its adverse effects and how to avoid them, summarize the applications of TMS in the investigation of different cerebral functions, and discuss the possibility of using TMS for the treatment of neuropsychiatric disorders.

Evidence for estrogen receptor beta-selective activity of Vitex agnus-castus and isolated flavones.

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Jarry, Hubertus; Spengler, Barbara; Porzel, Andrea; Schmidt, Juergen; Wuttke, Wolfgang; Christoffel, Volker

2003-10-01

Recent cell culture experiments indicated that extracts of Vitex agnus-castus (VAC) may contain yet unidentified phytoestrogens. Estrogenic actions are mediated via estrogen receptors (ER). To investigate whether VAC compounds bind to the currently known isoforms ERalpha or ERss, ligand binding assays (LBA) were performed. Subtype specific ER-LBA revealed a binding of VAC to ERss only. To isolate the ERss-selective compounds, the extract was fractionated by bio-guidance. The flavonoid apigenin was isolated and identified as the most active ERss-selective phytoestrogen in VAC. Other isolated compounds were vitexin and penduletin. These data demonstrate that the phytoestrogens in VAC are ERss-selective.

Computational analysis of transcranial magnetic stimulation in the presence of deep brain stimulation probes

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Syeda, F.; Holloway, K.; El-Gendy, A. A.; Hadimani, R. L.

2017-05-01

Transcranial Magnetic Stimulation is an emerging non-invasive treatment for depression, Parkinson's disease, and a variety of other neurological disorders. Many Parkinson's patients receive the treatment known as Deep Brain Stimulation, but often require additional therapy for speech and swallowing impairment. Transcranial Magnetic Stimulation has been explored as a possible treatment by stimulating the mouth motor area of the brain. We have calculated induced electric field, magnetic field, and temperature distributions in the brain using finite element analysis and anatomically realistic heterogeneous head models fitted with Deep Brain Stimulation leads. A Figure of 8 coil, current of 5000 A, and frequency of 2.5 kHz are used as simulation parameters. Results suggest that Deep Brain Stimulation leads cause surrounding tissues to experience slightly increased E-field (Δ Emax =30 V/m), but not exceeding the nominal values induced in brain tissue by Transcranial Magnetic Stimulation without leads (215 V/m). The maximum temperature in the brain tissues surrounding leads did not change significantly from the normal human body temperature of 37 °C. Therefore, we ascertain that Transcranial Magnetic Stimulation in the mouth motor area may stimulate brain tissue surrounding Deep Brain Stimulation leads, but will not cause tissue damage.

Pudendal nerve stimulation and block by a wireless-controlled implantable stimulator in cats.

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Yang, Guangning; Wang, Jicheng; Shen, Bing; Roppolo, James R; de Groat, William C; Tai, Changfeng

2014-07-01

The study aims to determine the functionality of a wireless-controlled implantable stimulator designed for stimulation and block of the pudendal nerve. In five cats under α-chloralose anesthesia, the stimulator was implanted underneath the skin on the left side in the lower back along the sacral spine. Two tripolar cuff electrodes were implanted bilaterally on the pudendal nerves in addition to one bipolar cuff electrode that was implanted on the left side central to the tripolar cuff electrode. The stimulator provided high-frequency (5-20 kHz) biphasic stimulation waveforms to the two tripolar electrodes and low-frequency (1-100 Hz) rectangular pulses to the bipolar electrode. Bladder and urethral pressures were measured to determine the effects of pudendal nerve stimulation (PNS) or block. The maximal (70-100 cmH2O) urethral pressure generated by 20-Hz PNS applied via the bipolar electrode was completely eliminated by the pudendal nerve block induced by the high-frequency stimulation (6-15 kHz, 6-10 V) applied via the two tripolar electrodes. In a partially filled bladder, 20-30 Hz PNS (2-8 V, 0.2 ms) but not 5 Hz stimulation applied via the bipolar electrode elicited a large sustained bladder contraction (45.9 ± 13.4 to 52.0 ± 22 cmH2O). During cystometry, the 5 Hz PNS significantly (p < 0.05) increased bladder capacity to 176.5 ± 27.1% of control capacity. The wireless-controlled implantable stimulator successfully generated the required waveforms for stimulation and block of pudendal nerve, which will be useful for restoring bladder functions after spinal cord injury. © 2013 International Neuromodulation Society.

A new brain stimulation method: Noninvasive transcranial magneto–acoustical stimulation

International Nuclear Information System (INIS)

Yuan Yi; Chen Yu-Dong; Li Xiao-Li

2016-01-01

We investigate transcranial magneto–acoustical stimulation (TMAS) for noninvasive brain neuromodulation in vivo. TMAS as a novel technique uses an ultrasound wave to induce an electric current in the brain tissue in the static magnetic field. It has the advantage of high spatial resolution and penetration depth. The mechanism of TMAS onto a neuron is analyzed by combining the TMAS principle and Hodgkin–Huxley neuron model. The anesthetized rats are stimulated by TMAS, resulting in the local field potentials which are recorded and analyzed. The simulation results show that TMAS can induce neuronal action potential. The experimental results indicate that TMAS can not only increase the amplitude of local field potentials but also enhance the effect of focused ultrasound stimulation on the neuromodulation. In summary, TMAS can accomplish brain neuromodulation, suggesting a potentially powerful noninvasive stimulation method to interfere with brain rhythms for diagnostic and therapeutic purposes. (paper)

Spinal cord stimulation

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... this page: //medlineplus.gov/ency/article/007560.htm Spinal cord stimulation To use the sharing features on this page, please enable JavaScript. Spinal cord stimulation is a treatment for pain that uses ...

Stimulating thought: a functional MRI study of transcranial direct current stimulation in schizophrenia.

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Orlov, Natasza D; O'Daly, Owen; Tracy, Derek K; Daniju, Yusuf; Hodsoll, John; Valdearenas, Lorena; Rothwell, John; Shergill, Sukhi S

2017-09-01

Individuals with schizophrenia typically suffer a range of cognitive deficits, including prominent deficits in working memory and executive function. These difficulties are strongly predictive of functional outcomes, but there is a paucity of effective therapeutic interventions targeting these deficits. Transcranial direct current stimulation is a novel neuromodulatory technique with emerging evidence of potential pro-cognitive effects; however, there is limited understanding of its mechanism. This was a double-blind randomized sham controlled pilot study of transcranial direct current stimulation on a working memory (n-back) and executive function (Stroop) task in 28 individuals with schizophrenia using functional magnetic resonance imaging. Study participants received 30 min of real or sham transcranial direct current stimulation applied to the left frontal cortex. The 'real' and 'sham' groups did not differ in online working memory task performance, but the transcranial direct current stimulation group demonstrated significant improvement in performance at 24 h post-transcranial direct current stimulation. Transcranial direct current stimulation was associated with increased activation in the medial frontal cortex beneath the anode; showing a positive correlation with consolidated working memory performance 24 h post-stimulation. There was reduced activation in the left cerebellum in the transcranial direct current stimulation group, with no change in the middle frontal gyrus or parietal cortices. Improved performance on the executive function task was associated with reduced activity in the anterior cingulate cortex. Transcranial direct current stimulation modulated functional activation in local task-related regions, and in more distal nodes in the network. Transcranial direct current stimulation offers a potential novel approach to altering frontal cortical activity and exerting pro-cognitive effects in schizophrenia. © The Author (2017). Published by Oxford

The Codacs™ direct acoustic cochlear implant actuator: exploring alternative stimulation sites and their stimulation efficiency.

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Grossöhmichen, Martin; Salcher, Rolf; Kreipe, Hans-Heinrich; Lenarz, Thomas; Maier, Hannes

2015-01-01

This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia) in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW). Here the perilymph stimulation with a K-piston through a stapes footplate (SFP) fenestration (N = 10) as well as stimulation of the stapes head (SH) with a Bell prosthesis (N = 9), SFP stimulation with an Omega/Aerial prosthesis (N = 8) and reverse RW stimulation (N = 10) were performed in cadaveric human temporal bones (TBs). Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL) using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5-141.8 eq. dB SPL; Omega/Aerial: 123.6-143.9 eq. dB SPL), being significantly more efficient than K-piston perilymph stimulation (108.6-131.6 eq. dB SPL) and RW stimulation (108.3-128.2 eq. dB SPL). Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented.

In vitro magnetic stimulation: a simple stimulation device to deliver defined low intensity electromagnetic fields

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Stephanie Grehl

2016-11-01

Full Text Available Non-invasive electromagnetic field brain stimulation (NIBS appears to benefit human neurological and psychiatric conditions, although the optimal stimulation parameters and underlying mechanisms remain unclear. Although in vitro studies have begun to elucidate cellular mechanisms, stimulation is delivered by a range of coils (from commercially available human stimulation coils to laboratory-built circuits so that the electromagnetic fields induced within the tissue to produce the reported effects are ill-defined.Here we develop a simple in vitro stimulation device with plug-and-play features that allow delivery of a range of stimulation parameters. We chose to test low intensity repetitive magnetic stimulation (LI-rMS delivered at 3 frequencies to hindbrain explant cultures containing the olivocerebellar pathway. We used computational modelling to define the parameters of a stimulation circuit and coil that deliver a unidirectional homogeneous magnetic field of known intensity and direction, and therefore a predictable electric field, to the target. We built the coil to be compatible with culture requirements: stimulation within an incubator; a flat surface allowing consistent position and magnetic field direction; location outside the culture plate to maintain sterility and no heating or vibration. Measurements at the explant confirmed the induced magnetic field was homogenous and matched the simulation results. To validate our system we investigated biological effects following LI-rMS at 1 Hz, 10 Hz and biomimetic high frequency (BHFS, which we have previously shown induces neural circuit reorganisation. We found that gene expression was modified by LI-rMS in a frequency-related manner. Four hours after a single 10-minute stimulation session, the number of c-fos positive cells increased, indicating that our stimulation activated the tissue. Also, after 14 days of LI-rMS, the expression of genes normally present in the tissue was differentially

The Codacs™ direct acoustic cochlear implant actuator: exploring alternative stimulation sites and their stimulation efficiency.

Directory of Open Access Journals (Sweden)

Martin Grossöhmichen

Full Text Available This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW. Here the perilymph stimulation with a K-piston through a stapes footplate (SFP fenestration (N = 10 as well as stimulation of the stapes head (SH with a Bell prosthesis (N = 9, SFP stimulation with an Omega/Aerial prosthesis (N = 8 and reverse RW stimulation (N = 10 were performed in cadaveric human temporal bones (TBs. Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5-141.8 eq. dB SPL; Omega/Aerial: 123.6-143.9 eq. dB SPL, being significantly more efficient than K-piston perilymph stimulation (108.6-131.6 eq. dB SPL and RW stimulation (108.3-128.2 eq. dB SPL. Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented.

Evaluation of estrogenic potential of flavonoids using a recombinant yeast strain and MCF7/BUS cell proliferation assay.

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Flávia A Resende

Full Text Available Phytoestrogens are of interest because of their reported beneficial effects on many human maladies including cancer, neurodegeneration, cardiovascular disease and diabetes. Furthermore, there is a search for compounds with estrogenic activity that can replace estrogen in hormone replacement therapy during menopause, without the undesirable effects of estrogen, such as the elevation of breast cancer occurrence. Thus, the principal objective of this study was to assess the estrogenic activity of flavonoids with different hydroxylation patterns: quercetin, kaempferol, luteolin, fisetin, chrysin, galangin, flavone, 3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone via two different in vitro assays, the recombinant yeast assay (RYA and the MCF-7 proliferation assay (E-screen, since the most potent phytoestrogens are members of the flavonoid family. In these assays, kaempferol was the only compound that showed ERα-dependent transcriptional activation activity by RYA, showing 6.74±1.7 nM EEQ, besides acting as a full agonist for the stimulation of proliferation of MCF-7/BUS cells. The other compounds did not show detectable levels of interaction with ER under the conditions used in the RYA. However, in the E-screen assay, compounds such as galangin, luteolin and fisetin also stimulated the proliferation of MCF-7/BUS cells, acting as partial agonists. In the evaluation of antiestrogenicity, the compounds quercetin, chrysin and 3-hydroxyflavone significantly inhibited the cell proliferation induced by 17-β-estradiol in the E-screen assay, indicating that these compounds may act as estrogen receptor antagonists. Overall, it became clear in the assay results that the estrogenic activity of flavonoids was affected by small structural differences such as the number of hydroxyl groups, especially those on the B ring of the flavonoid.

Higher success rate with transcranial electrical stimulation of motor-evoked potentials using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery.

Science.gov (United States)

Shigematsu, Hideki; Kawaguchi, Masahiko; Hayashi, Hironobu; Takatani, Tsunenori; Iwata, Eiichiro; Tanaka, Masato; Okuda, Akinori; Morimoto, Yasuhiko; Masuda, Keisuke; Tanaka, Yuu; Tanaka, Yasuhito

2017-10-01

During spine surgery, the spinal cord is electrophysiologically monitored via transcranial electrical stimulation of motor-evoked potentials (TES-MEPs) to prevent injury. Transcranial electrical stimulation of motor-evoked potential involves the use of either constant-current or constant-voltage stimulation; however, there are few comparative data available regarding their ability to adequately elicit compound motor action potentials. We hypothesized that the success rates of TES-MEP recordings would be similar between constant-current and constant-voltage stimulations in patients undergoing spine surgery. The objective of this study was to compare the success rates of TES-MEP recordings between constant-current and constant-voltage stimulation. This is a prospective, within-subject study. Data from 100 patients undergoing spinal surgery at the cervical, thoracic, or lumbar level were analyzed. The success rates of the TES-MEP recordings from each muscle were examined. Transcranial electrical stimulation with constant-current and constant-voltage stimulations at the C3 and C4 electrode positions (international "10-20" system) was applied to each patient. Compound muscle action potentials were bilaterally recorded from the abductor pollicis brevis (APB), deltoid (Del), abductor hallucis (AH), tibialis anterior (TA), gastrocnemius (GC), and quadriceps (Quad) muscles. The success rates of the TES-MEP recordings from the right Del, right APB, bilateral Quad, right TA, right GC, and bilateral AH muscles were significantly higher using constant-voltage stimulation than those using constant-current stimulation. The overall success rates with constant-voltage and constant-current stimulations were 86.3% and 68.8%, respectively (risk ratio 1.25 [95% confidence interval: 1.20-1.31]). The success rates of TES-MEP recordings were higher using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery. Copyright © 2017

Music acupuncture stimulation method.

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Brătilă, F; Moldovan, C

2007-01-01

Harmonic Medicine is the model using the theory that the body rhythms synchronize to an outer rhythm applied for therapeutic purpose, can restores the energy balance in acupuncture channels and organs and the condition of well-being. The purpose of this scientific work was to demonstrate the role played by harmonic sounds in the stimulation of the Lung (LU) Meridian (Shoutaiyin Feijing) and of the Kidney (KI) Meridian (Zushaoyin Shenjing). It was used an original method that included: measurement and electronic sound stimulation of the Meridian Entry Point, measurement of Meridian Exit Point, computer data processing, bio feed-back adjustment of the music stimulation parameters. After data processing, it was found that the sound stimulation of the Lung Meridian Frequency is optimal between 122 Hz and 128 Hz, with an average of 124 Hz (87% of the subjects) and for Kidney Meridian from 118 Hz to 121 Hz, with an average of 120 Hz (67% of the subjects). The acupuncture stimulation was more intense for female subjects (> 7%) than for the male ones. We preliminarily consider that an informational resonance phenomenon can be developed between the acupuncture music stimulation frequency and the cellular dipole frequency, being a really "resonant frequency signature" of an acupoint. The harmonic generation and the electronic excitation or low-excitation status of an acupuncture point may be considered as a resonance mechanism. By this kind of acupunctural stimulation, a symphony may act and play a healer role.

Low intensity transcranial electric stimulation

DEFF Research Database (Denmark)

Antal, Andrea; Alekseichuk, I; Bikson, M

2017-01-01

Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears...

Approximating transcranial magnetic stimulation with electric stimulation in mouse: a simulation study.

Science.gov (United States)

Barnes, Walter L; Lee, Won Hee; Peterchev, Angel V

2014-01-01

Rodent models are valuable for preclinical examination of novel therapeutic techniques, including transcranial magnetic stimulation (TMS). However, comparison of TMS effects in rodents and humans is confounded by inaccurate scaling of the spatial extent of the induced electric field in rodents. The electric field is substantially less focal in rodent models of TMS due to the technical restrictions of making very small coils that can handle the currents required for TMS. We examine the electric field distributions generated by various electrode configurations of electric stimulation in an inhomogeneous high-resolution finite element mouse model, and show that the electric field distributions produced by human TMS can be approximated by electric stimulation in mouse. Based on these results and the limits of magnetic stimulation in mice, we argue that the most practical and accurate way to model focal TMS in mice is electric stimulation through either cortical surface electrodes or electrodes implanted halfway through the mouse cranium. This approach could allow much more accurate approximation of the human TMS electric field focality and strength than that offered by TMS in mouse, enabling, for example, focal targeting of specific cortical regions, which is common in human TMS paradigms.

Interaction of transcranial magnetic stimulation and electrical transmastoid stimulation in human subjects

DEFF Research Database (Denmark)

Taylor, Janet L; Petersen, Nicolas Caesar; Butler, Jane E

2002-01-01

Transcranial magnetic stimulation activates corticospinal neurones directly and transsynaptically and hence, activates motoneurones and results in a response in the muscle. Transmastoid stimulation results in a similar muscle response through activation of axons in the spinal cord. This study...... was designed to determine whether the two stimuli activate the same descending axons. Responses to transcranial magnetic stimuli paired with electrical transmastoid stimuli were examined in biceps brachii in human subjects. Twelve interstimulus intervals (ISIs) from -6 ms (magnet before transmastoid) to 5 ms......-wave, facilitation still occurred at ISIs of -6 and -5 ms and depression of the paired response at ISIs of 0, 1, 4 and 5 ms. The interaction of the response to transmastoid stimulation with the multiple descending volleys elicited by magnetic stimulation of the cortex is complex. However, depression of the response...

Feldspar, Infrared Stimulated Luminescence

DEFF Research Database (Denmark)

Jain, Mayank

2014-01-01

This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

Prostate cancer: The main risk and protective factors-Epigenetic modifications.

Science.gov (United States)

Adjakly, Mawussi; Ngollo, Marjolaine; Dagdemir, Aslihan; Judes, Gaëlle; Pajon, Amaury; Karsli-Ceppioglu, Seher; Penault-Llorca, Frédérique; Boiteux, Jean-Paul; Bignon, Yves-Jean; Guy, Laurent; Bernard-Gallon, Dominique

2015-02-01

With 13 million new cases worldwide every year, prostate cancer is as a very real public health concern. Prostate cancer is common in over-50s men and the sixth-leading cause of cancer-related death in men worldwide. Like all cancers, prostate cancer is multifactorial - there are non-modifiable risk factors like heredity, ethnicity and geographic location, but also modifiable risk factors such as diet. Diet-cancer linkages have risen to prominence in the last few years, with accruing epidemiological data pointing to between-population incidence differentials in numerous cancers. Indeed, there are correlations between fat-rich diet and risk of hormone-dependent cancers like prostate cancer and breast cancer. Diet is a risk factor for prostate cancer, but certain micronutrients in specific diets are considered protective factors against prostate cancer. Examples include tomato lycopene, green tea epigallocatechin gallate, and soy phytoestrogens. These micronutrients are thought to exert cancer-protective effects via anti-oxidant pathways and inhibition of cell proliferation. Here, we focus in on the effects of phytoestrogens, and chiefly genistein and daidzein, which are the best-researched to date. Soy phytoestrogens are nonsteroid molecules whose structural similarity lends them the ability to mimic the effects of 17ß-estradiol. On top of anti-oxidant effects, there is evidence that soy phytoestrogens can modulate the epigenetic modifications found in prostate cancer. We also studied the impact of phytoestrogens on epigenetic modifications in prostate cancer, with special focus on DNA methylation, miRNA-mediated regulation and histone modifications. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Noninvasive Transcranial Brain Stimulation and Pain

OpenAIRE

Rosen, Allyson C.; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

2009-01-01

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the tre...

Growth hormone stimulation test

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003377.htm Growth hormone stimulation test To use the sharing features on this page, please enable JavaScript. The growth hormone (GH) stimulation test measures the ability of ...

[Cellphone electromagnetic radiation damages the testicular ultrastructure of male rats].

Science.gov (United States)

Gao, Xiao-Hui; Hu, Hui-Rong; Ma, Xue-Lian; Chen, Jie; Zhang, Guo-Hong

2016-06-01

To investigate the influence of cellphone electromagnetic radiation (CER) on the testicular ultrastructure and the apoptosis of spermatogenic cells in male rats.atability, feasibility, applicability, and controllability in the construction of experimental animal models, we compared the major anatomic features of the penis of 20 adult beagle dogs with those of 10 adult men. Using microsurgical techniques, we performed cross-transplantation of the penis in the 20 (10 pairs) beagle dogs and observed the survival rate of the transplanted penises by FK506+MMF+MP immune induction. We compared the relevant indexes with those of the 10 cases of microsurgical replantation of the amputated penis. Thirty adult male SD rats were equally randomized into a 2 h CER, a 4 h CER, and a normal control group, the former two groups exposed to 30 days of 900 MHz CER for 2 and 4 hours a day, respectively, while the latter left untreated. Then the changes in the ultrastructure of the testis tissue were observed under the transmission electron microscope and the apoptosis of the spermatogenic cells was determined by TUNEL. Compared with the normal controls, the rats of the 2 h CER group showed swollen basement membrane of seminiferous tubules, separated tight junction of Sertoli cells, increased cell intervals, apparent vacuoles and medullization in some mitochondria, and increased apoptosis of spermatogenic cells, mainly the apoptosis of primary spermatocytes (P<0.05 ). In comparison with the 2 h CER group, the animals of the 4 h CER group exhibited swollen basement membrane of seminiferous tubules, more separated tight junction of Sertoli cells, wider cell intervals, incomplete membrane of spermatogonial cells, fragments of cytoplasm, nuclear pyknosis and notch, slight dilation of perinuclear space, abnormalities of intracellular mitochondria with vacuoles, fuzzy structure, and fusion or disappearance of some cristae, and increased damage of mitochondria and apoptosis of spermatogenic

Avoiding Internal Capsule Stimulation With a New Eight-Channel Steering Deep Brain Stimulation Lead.

Science.gov (United States)

van Dijk, Kees J; Verhagen, Rens; Bour, Lo J; Heida, Ciska; Veltink, Peter H

2017-10-15

Novel deep brain stimulation (DBS) lead designs are currently entering the market, which are hypothesized to provide a way to steer the stimulation field away from neural populations responsible for side effects and towards populations responsible for beneficial effects. The objective of this study is to assess the performances of a new eight channel steering-DBS lead and compare this with a conventional cylindrical contact (CC) lead. The two leads were evaluated in a finite element electric field model combined with multicompartment neuron and axon models, representing the internal capsule (IC) fibers and subthalamic nucleus (STN) cells. We defined the optimal stimulation setting as the configuration that activated the highest percentage of STN cells, without activating any IC fibers. With this criterion, we compared monopolar stimulation using a single contact of the steering-DBS lead and CC lead, on three locations and four orientations of the lead. In addition, we performed a current steering test case by dividing the current over two contacts with the steering-DBS lead in its worst-case orientation. In most cases, the steering-DBS lead is able to stimulate a significantly higher percentage of STN cells compared to the CC lead using single contact stimulation or using a two contact current steering protocol when there is approximately a 1 mm displacement of the CC lead. The results also show that correct placement and orientation of the lead in the target remains an important aspect in achieving the optimal stimulation outcome. Currently, clinical trials are set up in Europe with a similar design as the steering-DBS lead. Our results illustrate the importance of the orientation of the new steering-DBS lead in avoiding side effects induced by stimulation of IC fibers. Therefore, in clinical trials sufficient attention should be paid to implanting the steering DBS-lead in the most effective orientation. © 2017 International Neuromodulation Society.

Evaluation of intradural stimulation efficiency and selectivity in a computational model of spinal cord stimulation.

Directory of Open Access Journals (Sweden)

Bryan Howell

Full Text Available Spinal cord stimulation (SCS is an alternative or adjunct therapy to treat chronic pain, a prevalent and clinically challenging condition. Although SCS has substantial clinical success, the therapy is still prone to failures, including lead breakage, lead migration, and poor pain relief. The goal of this study was to develop a computational model of SCS and use the model to compare activation of neural elements during intradural and extradural electrode placement. We constructed five patient-specific models of SCS. Stimulation thresholds predicted by the model were compared to stimulation thresholds measured intraoperatively, and we used these models to quantify the efficiency and selectivity of intradural and extradural SCS. Intradural placement dramatically increased stimulation efficiency and reduced the power required to stimulate the dorsal columns by more than 90%. Intradural placement also increased selectivity, allowing activation of a greater proportion of dorsal column fibers before spread of activation to dorsal root fibers, as well as more selective activation of individual dermatomes at different lateral deviations from the midline. Further, the results suggest that current electrode designs used for extradural SCS are not optimal for intradural SCS, and a novel azimuthal tripolar design increased stimulation selectivity, even beyond that achieved with an intradural paddle array. Increased stimulation efficiency is expected to increase the battery life of implantable pulse generators, increase the recharge interval of rechargeable implantable pulse generators, and potentially reduce stimulator volume. The greater selectivity of intradural stimulation may improve the success rate of SCS by mitigating the sensitivity of pain relief to malpositioning of the electrode. The outcome of this effort is a better quantitative understanding of how intradural electrode placement can potentially increase the selectivity and efficiency of SCS

Development of Femtosecond Stimulated Raman Spectroscopy: Stimulated Raman Gain via Elimination of Cross Phase Modulation

International Nuclear Information System (INIS)

Jin, Seung Min; Lee, Young Jong; Yu, Jong Wan; Kim, Seong Keun

2004-01-01

We have developed a new femtosecond probe technique by using stimulated Raman spectroscopy. The cross phase modulation in femtosecond time scale associated with off-resonant interaction was shown to be eliminated by integrating the transient gain/loss signal over the time delay between the Raman pump pulse and the continuum pulse. The stimulated Raman gain of neat cyclohexane was obtained to demonstrate the feasibility of the technique. Spectral and temporal widths of stimulated Raman spectra were controlled by using a narrow band pass filter. Femtosecond stimulated Raman spectroscopy was proposed as a highly useful probe in time-resolved vibrational spectroscopy

Noninvasive transcranial brain stimulation and pain.

Science.gov (United States)

Rosen, Allyson C; Ramkumar, Mukund; Nguyen, Tam; Hoeft, Fumiko

2009-02-01

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two noninvasive brain stimulation techniques that can modulate activity in specific regions of the cortex. At this point, their use in brain stimulation is primarily investigational; however, there is clear evidence that these tools can reduce pain and modify neurophysiologic correlates of the pain experience. TMS has also been used to predict response to surgically implanted stimulation for the treatment of chronic pain. Furthermore, TMS and tDCS can be applied with other techniques, such as event-related potentials and pharmacologic manipulation, to illuminate the underlying physiologic mechanisms of normal and pathological pain. This review presents a description and overview of the uses of two major brain stimulation techniques and a listing of useful references for further study.

Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation.

Science.gov (United States)

Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

2017-03-03

It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

Estrogenic plant foods of red colobus monkeys and mountain gorillas in Uganda.

Science.gov (United States)

Wasserman, Michael D; Taylor-Gutt, Alexandra; Rothman, Jessica M; Chapman, Colin A; Milton, Katharine; Leitman, Dale C

2012-05-01

Phytoestrogens, or naturally occurring estrogen-mimicking compounds, are found in many human plant foods, such as soybeans (Glycine max) and other legumes. Because the consumption of phytoestrogens may result in both health benefits of protecting against estrogen-dependent cancers and reproductive costs of disrupting the developing endocrine system, considerable biomedical research has been focused on the physiological and behavioral effects of these compounds. Despite this interest, little is known about the occurrence of phytoestrogens in the diets of wild primates, nor their likely evolutionary importance. We investigated the prevalence of estrogenic plant foods in the diets of two folivorous primate species, the red colobus monkey (Procolobus rufomitratus) of Kibale National Park and mountain gorilla (Gorilla beringei) of Bwindi Impenetrable National Park, both in Uganda. To examine plant foods for estrogenic activity, we screened 44 plant items (species and part) comprising 78.4% of the diet of red colobus monkeys and 53 plant items comprising 85.2% of the diet of mountain gorillas using transient transfection assays. At least 10.6% of the red colobus diet and 8.8% of the gorilla diet had estrogenic activity. This was mainly the result of the red colobus eating three estrogenic staple foods and the gorillas eating one estrogenic staple food. All estrogenic plants exhibited estrogen receptor (ER) subtype selectivity, as their phytoestrogens activated ERβ, but not ERα. These results demonstrate that estrogenic plant foods are routinely consumed by two folivorous primate species. Phytoestrogens in the wild plant foods of these two species and many other wild primates may have important implications for understanding primate reproductive ecology. Copyright © 2012 Wiley Periodicals, Inc.

Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility.

Science.gov (United States)

Eustache, Florence; Mondon, Françoise; Canivenc-Lavier, Marie Chantal; Lesaffre, Corinne; Fulla, Yvonne; Berges, Raymond; Cravedi, Jean Pierre; Vaiman, Daniel; Auger, Jacques

2009-08-01

The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood. We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility. Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays. The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production. Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

Electrical stimulation in exercise training

Science.gov (United States)

Kroll, Walter

1994-01-01

Electrical stimulation has a long history of use in medicine dating back to 46 A.D. when the Roman physician Largus found the electrical discharge of torpedo fishes useful in the treatment of pain produced by headache and gout. A rival Greek physician, Dioscorides, discounted the value of the torpedo fish for headache relief but did recommend its use in the treatment of hemorrhoids. In 1745, the Leyden jar and various sized electrostatic generators were used to treat angina pectoris, epilepsy, hemiplegia, kidney stones, and sciatica. Benjamin Franklin used an electrical device to treat successfully a young woman suffering from convulsive fits. In the late 1800's battery powered hydroelectric baths were used to treat chronic inflammation of the uterus while electrified athletic supporters were advertised for the treatment of male problems. Fortunately, such an amusing early history of the simple beginnings of electrical stimulation did not prevent eventual development of a variety of useful therapeutic and rehabilitative applications of electrical stimulation. Over the centuries electrical stimulation has survived as a modality in the treatment of various medical disorders with its primary application being in the rehabilitation area. Recently, a surge of new interest in electrical stimulation has been kindled by the work of a Russian sport scientist who reported remarkable muscle strength and endurance improvements in elite athletes. Yakov Kots reported his research on electric stimulation and strength improvements in 1977 at a Canadian-Soviet Exchange Symposium held at Concordia University in Montreal. Since then an explosion of new studies has been seen in both sport science and in medicine. Based upon the reported works of Kots and the present surge of new investigations, one could be misled as to the origin of electrical stimulation as a technique to increase muscle strength. As a matter of fact, electric stimulation has been used as a technique to improve

Electrocutaneous stimulation system for Braille reading.

Science.gov (United States)

Echenique, Ana Maria; Graffigna, Juan Pablo; Mut, Vicente

2010-01-01

This work is an assistive technology for people with visual disabilities and aims to facilitate access to written information in order to achieve better social inclusion and integration into work and educational activities. Two methods of electrical stimulation (by current and voltage) of the mechanoreceptors was tested to obtain tactile sensations on the fingertip. Current and voltage stimulation were tested in a Braille cell and line prototype, respectively. These prototypes are evaluated in 33 blind and visually impaired subjects. The result of experimentation with both methods showed that electrical stimulation causes sensations of touch defined in the fingertip. Better results in the Braille characters reading were obtained with current stimulation (85% accuracy). However this form of stimulation causes uncomfortable sensations. The latter feeling was minimized with the method of voltage stimulation, but with low efficiency (50% accuracy) in terms of identification of the characters. We concluded that electrical stimulation is a promising method for the development of a simple and unexpensive Braille reading system for blind people. We observed that voltage stimulation is preferred by the users. However, more experimental tests must be carry out in order to find the optimum values of the stimulus parameters and increase the accuracy the Braille characters reading.

A fully implantable rodent neural stimulator

Science.gov (United States)

Perry, D. W. J.; Grayden, D. B.; Shepherd, R. K.; Fallon, J. B.

2012-02-01

The ability to electrically stimulate neural and other excitable tissues in behaving experimental animals is invaluable for both the development of neural prostheses and basic neurological research. We developed a fully implantable neural stimulator that is able to deliver two channels of intra-cochlear electrical stimulation in the rat. It is powered via a novel omni-directional inductive link and includes an on-board microcontroller with integrated radio link, programmable current sources and switching circuitry to generate charge-balanced biphasic stimulation. We tested the implant in vivo and were able to elicit both neural and behavioural responses. The implants continued to function for up to five months in vivo. While targeted to cochlear stimulation, with appropriate electrode arrays the stimulator is well suited to stimulating other neurons within the peripheral or central nervous systems. Moreover, it includes significant on-board data acquisition and processing capabilities, which could potentially make it a useful platform for telemetry applications, where there is a need to chronically monitor physiological variables in unrestrained animals.

Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study.

Science.gov (United States)

Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R

2016-01-01

A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-dependent (BOLD) signal changes across the whole brain linked to vertex stimulation. Thirty-two healthy participants to part in this study. Twenty-one were stimulated at the vertex, at 120% of resting motor threshold (RMT), with short bursts of 1 Hz TMS, while functional magnetic resonance imaging (fMRI) BOLD images were acquired. As a control condition, we delivered TMS pulses over the left primary motor cortex using identical parameters to 11 other participants. Vertex stimulation did not evoke increased BOLD activation at the stimulated site. By contrast we observed widespread BOLD deactivations across the brain, including regions within the default mode network (DMN). To examine the effects of vertex stimulation a functional connectivity analysis was conducted. The results demonstrated that stimulating the vertex with suprathreshold TMS reduced neural activity in brain regions related to the DMN but did not influence the functional connectivity of this network. Our findings provide brain imaging evidence in support of the use of vertex simulation as a control condition in TMS but confirm that vertex TMS induces regional widespread decreases in BOLD activation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Noninvasive Stimulation of the Human Brain

DEFF Research Database (Denmark)

Di Lazzaro, Vincenzo; Rothwell, John; Capogna, Marco

2017-01-01

Noninvasive brain stimulation methods, such as transcranial electric stimulation and transcranial magnetic stimulation are widely used tools for both basic research and clinical applications. However, the cortical circuits underlying their effects are poorly defined. Here we review the current...

Reducing interaction in simultaneous paired stimulation with CI.

Directory of Open Access Journals (Sweden)

Dirk Vellinga

Full Text Available In this study simultaneous paired stimulation of electrodes in cochlear implants is investigated by psychophysical experiments in 8 post-lingually deaf subjects (and one extra subject who only participated in part of the experiments. Simultaneous and sequential monopolar stimulation modes are used as references and are compared to channel interaction compensation, partial tripolar stimulation and a novel sequential stimulation strategy named phased array compensation. Psychophysical experiments are performed to investigate both the loudness integration during paired stimulation at the main electrodes as well as the interaction with the electrode contact located halfway between the stimulating pair. The study shows that simultaneous monopolar stimulation has more loudness integration on the main electrodes and more interaction in between the electrodes than sequential stimulation. Channel interaction compensation works to reduce the loudness integration at the main electrodes, but does not reduce the interaction in between the electrodes caused by paired stimulation. Partial tripolar stimulation uses much more current to reach the needed loudness, but shows the same interaction in between the electrodes as sequential monopolar stimulation. In phased array compensation we have used the individual impedance matrix of each subject to calculate the current needed on each electrode to exactly match the stimulation voltage along the array to that of sequential stimulation. The results show that the interaction in between the electrodes is the same as monopolar stimulation. The strategy uses less current than partial tripolar stimulation, but more than monopolar stimulation. In conclusion, the paper shows that paired stimulation is possible if the interaction is compensated.

The safety of transcranial magnetic stimulation with deep brain stimulation instruments

OpenAIRE

Shimojima, Yoshio; Morita, Hiroshi; Nishikawa, Noriko; Kodaira, Minori; Hashimoto, Takao; Ikeda, Shu-ichi

2010-01-01

Objectives: Transcranial magnetic stimulation (TMS) has been employed in patients with an implanted deep brain Stimulation (DBS) device. We investigated the safety of TMS using Simulation models with an implanted DBS device. Methods: The DBS lead was inserted into plastic phantoms filled with dilute gelatin showing impedance similar to that of human brain. TMS was performed with three different types of magnetic coil. During TMS (I) electrode movement, (2) temperature change around the lead, ...

Optical stimulator for vision-based sensors

DEFF Research Database (Denmark)

Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

2014-01-01

We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...

Mimicking muscle activity with electrical stimulation

Science.gov (United States)

Johnson, Lise A.; Fuglevand, Andrew J.

2011-02-01

Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

Twiddler's syndrome in spinal cord stimulation.

Science.gov (United States)

Al-Mahfoudh, Rafid; Chan, Yuen; Chong, Hsu Pheen; Farah, Jibril Osman

2016-01-01

The aims are to present a case series of Twiddler's syndrome in spinal cord stimulators with analysis of the possible mechanism of this syndrome and discuss how this phenomenon can be prevented. Data were collected retrospectively between 2007 and 2013 for all patients presenting with failure of spinal cord stimulators. The diagnostic criterion for Twiddler's syndrome is radiological evidence of twisting of wires in the presence of failure of spinal cord stimulation. Our unit implants on average 110 spinal cord stimulators a year. Over the 5-year study period, all consecutive cases of spinal cord stimulation failure were studied. Three patients with Twiddler's syndrome were identified. Presentation ranged from 4 to 228 weeks after implantation. Imaging revealed repeated rotations and twisting of the wires of the spinal cord stimulators leading to hardware failure. To the best of our knowledge this is the first reported series of Twiddler's syndrome with implantable pulse generators (IPGs) for spinal cord stimulation. Hardware failure is not uncommon in spinal cord stimulation. Awareness and identification of Twiddler's syndrome may help prevent its occurrence and further revisions. This may be achieved by implanting the IPG in the lumbar region subcutaneously above the belt line. Psychological intervention may have a preventative role for those who are deemed at high risk of Twiddler's syndrome from initial psychological screening.

Evaluation of different types of rooting stimulators

Directory of Open Access Journals (Sweden)

Petr Salaš

2012-01-01

Full Text Available This paper focuses on the assessment of selected stimulators, especially from Rhizopon product line, which are used for rooting and root system enhancement in various ornamental woody species. Two available methods of cuttings stimulation were selected from the available range of rooting stimulators: stimulation by long-term immersion in solutions or treatment of cuttings with powder stimulators. The experiment involved stimulators with two active components, currently the most commonly used phytohormones for this purpose – IBA and NAA – that were applied in different concentrations. The experiment took place in three propagation terms with twelve coniferous and deciduous shrub varieties. The results of the experiment show the different reactions of the individual species as well as varieties on the respective term of propagation and used form of stimulator.

Step-wise stimulated martensitic transformations

International Nuclear Information System (INIS)

Airoldi, G.; Riva, G.

1991-01-01

NiTi alloys, widely known both for their shape memory properties and for unusual pseudoelastic behaviour, are now on the forefront attention for step-wise induced memory processes, thermal or stress stimulated. Literature results related to step-wise stimulated martensite (direct transformation) are examined and contrasted with step-wise thermal stimulated parent phase (reverse transformation). Hypothesis are given to explain the key characters of both transformations, a thermodynamic model from first principles being till now lacking

The Underlying Mechanism of Preventing Facial Nerve Stimulation by Triphasic Pulse Stimulation in Cochlear Implant Users Assessed With Objective Measure.

Science.gov (United States)

Bahmer, Andreas; Baumann, Uwe

2016-10-01

Triphasic pulse stimulation prevents from facial nerve stimulation (FNS) because of a different electromyographic input-output function compared with biphasic pulse stimulation. FNS is sometimes observed in cochlear implant users as an unwanted side effect of electrical stimulation of the auditory nerve. The common stimulation applied in current cochlear implant consists of biphasic pulse patterns. Two common clinical remedies to prevent unpleasant FNS caused by activation of certain electrodes are to expand their pulse phase duration or simply deactivate them. Unfortunately, in some patients these methods do not provide sufficient FNS prevention. In these patients triphasic pulse can prevent from FNS. The underlying mechanism is yet unclear. Electromyographic (EMG) recordings of muscles innervated by the facial nerve (musculi orbicularis ori and oculi) were applied to quantitatively assess the effects on FNS. Triphasic and biphasic fitting maps were compared in four subjects with severe FNS. Based on the recordings, a model is presented which intends to explain the beneficial effects of triphasic pulse application. Triphasic stimulation provided by fitting of an OPUS 2 speech processor device. For three patients, EMG was successfully recorded depending on stimulation level up to uncomfortable and intolerable FNS stimulation as upper boarder. The obtained EMG recordings demonstrated high individual variability. However, a difference between the input-output function for biphasic and triphasic pulse stimulation was visually observable. Compared with standard biphasic stimulation, triphasic pulses require higher stimulation levels to elicit an equal amount of FNS, as reflected by EMG amplitudes. In addition, we assume a steeper slope of the input-output function for biphasic pulse stimulation compared with triphasic pulse stimulation. Triphasic pulse stimulation prevents from FNS because of a smaller gradient of EMG input-output function compared with biphasic pulse

Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording

Directory of Open Access Journals (Sweden)

James eDowsett

2016-03-01

Full Text Available Transcranial alternating current stimulation (tACS has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01. In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.

Effects of contraction mode and stimulation frequency on electrical stimulation-induced skeletal muscle hypertrophy.

Science.gov (United States)

Ashida, Yuki; Himori, Koichi; Tatebayashi, Daisuke; Yamada, Ryotaro; Ogasawara, Riki; Yamada, Takashi

2018-02-01

We compared the skeletal muscle hypertrophy resulting from isometric (Iso) or eccentric (Ecc) electrical stimulation (ES) training with different stimulation frequencies. Male Wistar rats were assigned to the Iso and Ecc groups. These were divided into three further subgroups that were stimulated at 10 Hz (Iso-10 and Ecc-10), 30 Hz (Iso-30 and Ecc-30), or 100 Hz (Iso-100 and Ecc-100). In experiment 1, the left plantarflexor muscles were stimulated every other day for 3 wk. In experiment 2, mammalian target of rapamycin complex 1 (mTORC1) signaling was investigated 6 h after one bout of ES. The contralateral right muscle served as a control (non-ES). Ecc contractions comprised forced dorsiflexion combined with ES. The peak torque and torque-time integral during ES were higher in the Ecc group than that in the Iso group in all stimulation frequencies examined. The gastrocnemius muscle weight normalized to body weight in ES side was increased compared with the non-ES side by 6, 7, and 17% in the Ecc-30, Iso-100, and Ecc-100 groups, respectively, with a greater gain in Ecc-100 than the Ecc-30 and Iso-100 groups. The p70S6K (Thr389) phosphorylation level was higher in the Ecc-30 and -100 than in the Iso-30 and -100 groups, respectively. The peak torque and torque-time integral were highly correlated with the magnitude of increase in muscle mass and the phosphorylation of p70S6K. These data suggest that ES-induced muscle hypertrophy and mTORC1 activity are determined by loading intensity and volume during muscle contraction independent of the contraction mode. NEW & NOTEWORTHY Eccentric contraction and high-frequency stimulation (HFS) are regarded as an effective way to increase muscle mass by electrical stimulation (ES) training. However, little is known about whether muscle hypertrophy is affected by contraction mode and stimulation frequency in ES training. Here, we provide the evidence that muscle hypertrophy and mammalian target of rapamycin complex 1 activity are

Avoiding Internal Capsule Stimulation With a New Eight-Channel Steering Deep Brain Stimulation Lead

NARCIS (Netherlands)

van Dijk, Kees J.; Verhagen, Rens; Bour, Lo J.; Heida, Ciska; Veltink, Peter H.

2017-01-01

Objective: Novel deep brain stimulation (DBS) lead designs are currently entering the market, which are hypothesized to provide a way to steer the stimulation field away from neural populations responsible for side effects and towards populations responsible for beneficial effects. The objective of

Brain stimulation in posttraumatic stress disorder

Directory of Open Access Journals (Sweden)

Vladan Novakovic

2011-10-01

Full Text Available Posttraumatic stress disorder (PTSD is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT and Cranial electrotherapy stimulation (CES have both been in use for decades; transcranial magnetic stimulation (TMS, magnetic seizure therapy (MST, deep brain stimulation (DBS, transcranial Direct Current Stimulation (tDCS, and vagus nerve stimulation (VNS have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES, depression (ECT, CES, rTMS, VNS, DBS, obsessive-compulsive disorder (OCD (DBS, essential tremor, dystonia (DBS, epilepsy (DBS, VNS, Parkinson Disease (DBS, pain (CES, and insomnia (CES. To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in

A Programmable High-Voltage Compliance Neural Stimulator for Deep Brain Stimulation in Vivo

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Cihun-Siyong Alex Gong

2015-05-01

Full Text Available Deep brain stimulation (DBS is one of the most effective therapies for movement and other disorders. The DBS neurosurgical procedure involves the implantation of a DBS device and a battery-operated neurotransmitter, which delivers electrical impulses to treatment targets through implanted electrodes. The DBS modulates the neuronal activities in the brain nucleus for improving physiological responses as long as an electric discharge above the stimulation threshold can be achieved. In an effort to improve the performance of an implanted DBS device, the device size, implementation cost, and power efficiency are among the most important DBS device design aspects. This study aims to present preliminary research results of an efficient stimulator, with emphasis on conversion efficiency. The prototype stimulator features high-voltage compliance, implemented with only a standard semiconductor process, without the use of extra masks in the foundry through our proposed circuit structure. The results of animal experiments, including evaluation of evoked responses induced by thalamic electrical stimuli with our fabricated chip, were shown to demonstrate the proof of concept of our design.

Colony-stimulating factor (CSF) radioimmunoassay: detection of a CSF subclass stimulating macrophage production

International Nuclear Information System (INIS)

Stanley, E.R.

1979-01-01

Colony-stimulating factors (CSFs) stimulate the differentiation of immature precursor cells to mature granulocytes and macrophages. Purified 125 I-labeled murine L cell CSF has been used to develop a radioimmunoassay (RIA) that detects a subclass of CSFs that stimulates macrophage production. Murine CSF preparations that contain this subclass of CSF compete for all of the CSF binding sites on anti-L cell CSF antibody. With the exception of mouse serum, which can contain inhibitors of the bioassay, there is complete correspondence between activities determined by RIA and those determined by bioassay. The RIA is slightly more sensitive than the bioassay, detecting approximately 0.3 fmol of purified L cell CSF. It can also detect this subclass of CSF in chickens, rats, and humans. In the mouse, the subclass is distinguished from other CSFs by a murine cell bioassay dose-response curve in which 90% of the response occurs over a 10-fold (rather than a 100-fold) increase in concentration, by stimulating the formations of colonies contaning a high proportion of mononuclear (rather than granulocytic) cells, and by certain physical characteristics

Suppression of T cell-induced osteoclast formation

Energy Technology Data Exchange (ETDEWEB)

Karieb, Sahar; Fox, Simon W., E-mail: Simon.fox@plymouth.ac.uk

2013-07-12

Highlights: •Genistein and coumestrol prevent activated T cell induced osteoclast formation. •Anti-TNF neutralising antibodies prevent the pro-osteoclastic effect of activated T cells. •Phytoestrogens inhibit T cell derived TNF alpha and inflammatory cytokine production. •Phytoestrogens have a broader range of anti-osteoclastic actions than other anti-resorptives. -- Abstract: Inhibition of T cell derived cytokine production could help suppress osteoclast differentiation in inflammatory skeletal disorders. Bisphosphonates are typically prescribed to prevent inflammatory bone loss but are not tolerated by all patients and are associated with an increased risk of osteonecrosis of the jaw. In light of this other anti-resorptives such as phytoestrogens are being considered. However the effect of phytoestrogens on T cell-induced osteoclast formation is unclear. The effect of genistein and coumestrol on activated T cell-induced osteoclastogenesis and cytokine production was therefore examined. Concentrations of genistein and coumestrol (10{sup −7} M) previously shown to directly inhibit osteoclast formation also suppressed the formation of TRAP positive osteoclast induced by con A activated T cells, which was dependent on inhibition of T cell derived TNF-α. While both reduced osteoclast formation their mechanism of action differed. The anti-osteoclastic effect of coumestrol was associated with a dual effect on con A induced T cell proliferation and activation; 10{sup −7} M coumestrol significantly reducing T cell number (0.36) and TNF-α (0.47), IL-1β (0.23) and IL-6 (0.35) expression, whereas genistein (10{sup −7} M) had no effect on T cell number but a more pronounced effect on T cell differentiation reducing expression of TNF-α (0.49), IL-1β (0.52), IL-6 (0.71) and RANKL (0.71). Phytoestrogens therefore prevent the pro-osteoclastic action of T cells suggesting they may have a role in the control of inflammatory bone loss.

growth stimulant

African Journals Online (AJOL)

Effects of timing and duration of supplementation of LIVFIT VET ® (growth stimulant) as substitute for fish meal on the growth performance, haematology and clinical enzymes concentration of growing pigs.

Tonic aortic depressor nerve stimulation does not impede baroreflex dynamic characteristics concomitantly mediated by the stimulated nerve.

Science.gov (United States)

Kawada, Toru; Turner, Michael J; Shimizu, Shuji; Kamiya, Atsunori; Shishido, Toshiaki; Sugimachi, Masaru

2018-03-01

Although electrical activation of the carotid sinus baroreflex (baroreflex activation therapy) is being explored as a device therapy for resistant hypertension, possible effects on baroreflex dynamic characteristics of interaction between electrical stimulation and pressure inputs are not fully elucidated. To examine whether the electrical stimulation of the baroreceptor afferent nerve impedes normal short-term arterial pressure (AP) regulation mediated by the stimulated nerve, we electrically stimulated the right aortic depressor nerve (ADN) while estimating the baroreflex dynamic characteristics by imposing pressure inputs to the isolated baroreceptor region of the right ADN in nine anesthetized rats. A Gaussian white noise signal with a mean of 120 mmHg and standard deviation of 20 mmHg was used for the pressure perturbation. A tonic ADN stimulation (2 or 5 Hz, 10 V, 0.1-ms pulse width) decreased mean sympathetic nerve activity (367.0 ± 70.9 vs. 247.3 ± 47.2 arbitrary units, P ADN stimulation did not affect the slope of dynamic gain in the neural arc transfer function from pressure perturbation to sympathetic nerve activity (16.9 ± 1.0 vs. 14.7 ± 1.6 dB/decade, not significant). These results indicate that electrical stimulation of the baroreceptor afferent nerve does not significantly impede the dynamic characteristics of the arterial baroreflex concomitantly mediated by the stimulated nerve. Short-term AP regulation by the arterial baroreflex may be preserved during the baroreflex activation therapy.

Avoiding Internal Capsule Stimulation With a New Eight-Channel Steering Deep Brain Stimulation Lead

NARCIS (Netherlands)

van Dijk, Kees J.; Verhagen, Rens; Bour, Lo J.; Heida, Ciska; Veltink, Peter H.

2017-01-01

Novel deep brain stimulation (DBS) lead designs are currently entering the market, which are hypothesized to provide a way to steer the stimulation field away from neural populations responsible for side effects and towards populations responsible for beneficial effects. The objective of this study

Tactile stimulation interventions: influence of stimulation parameters on sensorimotor behavior and neurophysiological correlates in healthy and clinical samples.

Science.gov (United States)

Parianen Lesemann, Franca H; Reuter, Eva-Maria; Godde, Ben

2015-04-01

The pure exposure to extensive tactile stimulation, without the requirement of attention or active training, has been revealed to enhance sensorimotor functioning presumably due to an induction of plasticity in the somatosensory cortex. The induced effects, including increased tactile acuity and manual dexterity have repeatedly been observed in basic as well as clinical research. However, results vary greatly in respect to the strength and direction of the effects on the behavioral and on the brain level. Multiple evidences show that differences in the stimulation protocols (e.g., two vs. multiple stimulation sites) and parameters (e.g., duration, frequency, and amplitude) might contribute to this variability of effects. Nevertheless, stimulation protocols have not been comprehensively compared yet. Identifying favorable parameters for tactile stimulation interventions is especially important because of its possible application as a treatment option for patients suffering from sensory loss, maladaptive plasticity, or certain forms of motor impairment. This review aims to compare the effects of different tactile stimulation protocols and to assess possible implications for tactile interventions. Our goal is to identify ways of optimizing stimulation protocols to improve sensorimotor performance. To this end, we reviewed research on tactile stimulation in the healthy population, with a focus on the effectiveness of the applied parameters regarding psychophysiological measures. We discuss the association of stimulation-induced changes on the behavioral level with alterations in neural representations and response characteristics. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of stimulation parameters and electrode location on thresholds for epidural stimulation of cat motor cortex

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Wongsarnpigoon, Amorn; Grill, Warren M.

2011-12-01

Epidural electrical stimulation (ECS) of the motor cortex is a developing therapy for neurological disorders. Both placement and programming of ECS systems may affect the therapeutic outcome, but the treatment parameters that will maximize therapeutic outcomes and minimize side effects are not known. We delivered ECS to the motor cortex of anesthetized cats and investigated the effects of electrode placement and stimulation parameters on thresholds for evoking motor responses in the contralateral forelimb. Thresholds were inversely related to stimulation frequency and the number of pulses per stimulus train. Thresholds were lower over the forelimb representation in motor cortex (primary site) than surrounding sites (secondary sites), and thresholds at sites 4 mm away. Electrode location and montage influenced the effects of polarity on thresholds: monopolar anodic and cathodic thresholds were not significantly different over the primary site, cathodic thresholds were significantly lower than anodic thresholds over secondary sites and bipolar thresholds were significantly lower with the anode over the primary site than with the cathode over the primary site. A majority of bipolar thresholds were either between or equal to the respective monopolar thresholds, but several bipolar thresholds were greater than or less than the monopolar thresholds of both the anode and cathode. During bipolar stimulation, thresholds were influenced by both electric field superposition and indirect, synaptically mediated interactions. These results demonstrate the influence of stimulation parameters and electrode location during cortical stimulation, and these effects should be considered during the programming of systems for therapeutic cortical stimulation.

Phenotypic expression of partial AZFc deletions is independent of the variations in DAZL and BOULE in a Han population.

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Chen, Pu; Ma, Mingyi; Li, Lei; Zhang, Sizhong; Su, Dan; Ma, Yongxin; Liu, Yunqiang; Tao, Dachang; Lin, Li; Yang, Yuan

2010-01-01

DAZ on the Y chromosome and 2 autosomal ancestral genes DAZL and BOULE are suggested to represent functional conservation in spermatogenesis. The partial AZFc deletion, a common mutation of the Y chromosome, always involves 2 DAZ copies and represents a different spermatogenic phenotype in the populations studied. To investigate whether the variations in DAZL and BOULE influence partial AZFc deletion phenotype, the genotyping of 15 loci variations, including 4 known mutations and 11 single-nucleotide polymorphisms (SNPs), was carried out in 157 azoo-/oligzoospermic men and 57 normozoospermic men, both groups with partial AZFc deletions. The frequencies of the alleles, genotypes, and haplotypes of the variations were compared between the 2 groups. As a result, for 9 exonic variations in DAZL and BOULE, only T12A was observed in both groups with similar frequency, and I71V was identified in an azoospermic man with b2/b3 deletion, whereas the rest were absent in the population. The distribution of DAZL haplotypes from 4 variations, including T12A, and of BOULE haplotypes from 2 SNPs was similar between men with normozoospermia and spermatogenic failure. Our findings indicate that the contribution of DAZL and BOULE variations to spermatogenic impairment in men with the DAZ defect is greatly limited, suggesting that expression of spermatogenic phenotypes of partial AZFc deletions is independent of the variations in DAZL and BOULE in the Han population.

Effect of isoflavone-enriched soybean flour, zinc (Zn and vitamin E in the ration on testosterone level and total permatogenic cell in seminiferous tubules of rat

Directory of Open Access Journals (Sweden)

Astuti

2008-12-01

Full Text Available The objective of this experiment are to evaluate the effects of isoflavoneen-enriched soybean flour, zinc (Zn and vitamin E on testosterone level of male rats and total spermatogenic cells in the seminiferous tubules of rat testes as animal model. Diet was given as isonitrogen and isocaloric with 15% of dietary protein. Thirty male Sprague Dawley rats were divided into six groups and treated with isoflavoneen-riched soybean flour, Zn and vitamin E in different combination. Isoflavoneen-riched soybean flour (3mg/day was given by oral administration, whereas Zn and vitamin E were mixed wih the basic diet. The treatment was done for 2 month. Results indicated that complete treatment of isoflavoneen-riched soybean flour, Zn and vitamin E on male rats increased testosteron level and total spermatogenic cells in comparison with single treatment and the other combination. The best results showed in the group that given isoflavoneen-enriched soybean flour with diet containing both Zn and vitamin E i.e; testosteron level 3.49 ± 0.31 ng/ml; while the number of spermatogonia, spermatocytes, early spermatids, late spermatids, and total spermatogenic cells were 37.56 ± 4.48, 67 ± 4.72, 287.11 ± 31.75, 227.22 ± 29.78, and 618.89 ± 47.38, respectively. It was concluded that synergic interaction between isoflavoneen-enriched soybean flour, Zn and vitamin E increased testosteron level and total spermatogenic cells of rat testes.

Pharmacological interventions for adolescents and adults with ADHD: stimulant and nonstimulant medications and misuse of prescription stimulants

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Weyandt LL

2014-09-01

Full Text Available Lisa L Weyandt, Danielle R Oster, Marisa E Marraccini, Bergljot Gyda Gudmundsdottir, Bailey A Munro, Brynheld Martinez Zavras, Ben Kuhar Department of Psychology, University of Rhode Island, Kingston, RI, USA Abstract: Attention-deficit/hyperactivity disorder (ADHD is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity that cause functional impairment. Recent research indicates that symptoms persist into adulthood in the majority of cases, with prevalence estimates of approximately 5% in the school age population and 2.5%–4% in the adult population. Although students with ADHD are at greater risk for academic underachievement and psychosocial problems, increasing numbers of students with ADHD are graduating from high school and pursuing higher education. Stimulant medications are considered the first line of pharmacotherapy for individuals with ADHD, including college students. Although preliminary evidence indicates that prescription stimulants are safe and effective for college students with ADHD when used as prescribed, very few controlled studies have been conducted concerning the efficacy of prescription stimulants with college students. In addition, misuse of prescription stimulants has become a serious problem on college campuses across the US and has been recently documented in other countries as well. The purpose of the present systematic review was to investigate the efficacy of prescription stimulants for adolescents and young adults with ADHD and the nonmedical use and misuse of prescription stimulants. Results revealed that both prostimulant and stimulant medications, including lisdexamfetamine dimesylate, methylphenidate, amphetamines, and mixed-amphetamine salts, are effective at reducing ADHD symptoms in adolescents and adults with ADHD. Findings also suggest that individuals with ADHD may have higher rates of stimulant misuse than individuals without the disorder, and

Frequency shifts in stimulated Raman scattering

International Nuclear Information System (INIS)

Zinth, W.; Kaiser, W.

1980-01-01

The nonresonant contributions to the nonlinear susceptibility chisup(()3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering. (orig.)

Optimal number of stimulation contacts for coordinated reset neuromodulation

Science.gov (United States)

Lysyansky, Borys; Popovych, Oleksandr V.; Tass, Peter A.

2013-01-01

In this computational study we investigate coordinated reset (CR) neuromodulation designed for an effective control of synchronization by multi-site stimulation of neuronal target populations. This method was suggested to effectively counteract pathological neuronal synchrony characteristic for several neurological disorders. We study how many stimulation sites are required for optimal CR-induced desynchronization. We found that a moderate increase of the number of stimulation sites may significantly prolong the post-stimulation desynchronized transient after the stimulation is completely switched off. This can, in turn, reduce the amount of the administered stimulation current for the intermittent ON–OFF CR stimulation protocol, where time intervals with stimulation ON are recurrently followed by time intervals with stimulation OFF. In addition, we found that the optimal number of stimulation sites essentially depends on how strongly the administered current decays within the neuronal tissue with increasing distance from the stimulation site. In particular, for a broad spatial stimulation profile, i.e., for a weak spatial decay rate of the stimulation current, CR stimulation can optimally be delivered via a small number of stimulation sites. Our findings may contribute to an optimization of therapeutic applications of CR neuromodulation. PMID:23885239

Estrogen sulfotransferases in breast and endometrial cancers.

Science.gov (United States)

Pasqualini, Jorge Raul

2009-02-01

Estrogen sulfotransferase is significantly more active in the normal breast cell (e.g., Human 7) than in the cancer cell (e.g., MCF-7). The data suggest that in breast cancer sulfoconjugated activity is carried out by another enzyme, the SULT1A, which acts at high concentration of the substrates. In breast cancer cells sulfotransferase (SULT) activity can be stimulated by various progestins: medrogestone, promegestone, and nomegestrol acetate, as well as by tibolone and its metabolites. SULT activities can also be controlled by other substances including phytoestrogens, celecoxib, flavonoids (e.g., quercetin, resveratrol), and isoflavones. SULT expression was localized in breast cancer cells, which can be stimulated by promegestone and correlated with the increase of the enzyme activity. The estrogen sulfotransferase (SULT1E1), which acts at nanomolar concentration of estradiol, can inactivate most of this hormone present in the normal breast; however, in the breast cancer cells, the sulfotransferase denoted as SULT1A1 is mainly present, and this acts at micromolar concentrations of E(2). A correlation was postulated among breast cancer cell proliferation, the effect of various progestins, and sulfotransferase stimulation. In conclusion, it is suggested that factors involved in the stimulation of the estrogen sulfotransferases could provide new possibilities for the treatment of patients with hormone-dependent breast and endometrial cancers.

Evaluation of various somatosensory stimulations for functional MRI

International Nuclear Information System (INIS)

Hara, Kazushi; Nakasato, Nobukazu; Mizoi, Kazuo; Yoshimoto, Takashi; Shimizu, Hiroaki.

1997-01-01

The aim of this functional magnetic resonance imaging (fMRI) study was to test detectability of activated area using various somatosensory stimulations. The following stimulations were performed in normal volunteers: regular or irregular electrical median nerve stimulation (n=5, each), tactile stimulation to the palm and fingers (n=8), pain stimulation to the index finger (n=5) or to the palm and fingers (n=5). fMRI was acquired with a spoiled gradient echo sequence at 1.5 T. Detectability of activated area was the highest when the pain stimulation was applied to the palm and fingers (80%). A successful rate for the tactile stimulation was 25%, and the other stimulations failed to demonstrate any activation. When successful, the highest signal activation on fMRI was seen on a sulcus, which presumably arose from a vein. The sulcus was defined as the central sulcus by somatosensory evoked field using a median nerve stimulation. Our study indicates that the pain stimulation to the palm and fingers may be a choice for the sensory fMRI. (author)

Economics of nuclear gas stimulation

Energy Technology Data Exchange (ETDEWEB)

Frank, G W [Austral Oil Company Incorporated, Houston, TX (United States); Coffer, H F; Luetkehans, G R [CER Geonuclear Corporation, Las Vegas, NV (United States)

1970-05-01

Nuclear stimulation of the Mesaverde Formation in the Piceance Basin appears to be the only available method that can release the contained gas economically. In the Rulison Field alone estimates show six to eight trillion cubic feet of gas may be made available by nuclear means, and possibly one hundred trillion cubic feet could be released in the Piceance Basin. Several problems remain to be solved before this tremendous gas reserve can be tapped. Among these are (1) rates of production following nuclear stimulation; (2) costs of nuclear stimulation; (3) radioactivity of the chimney gas; and (4) development of the ideal type of device to carry out the stimulations. Each of these problems is discussed in detail with possible solutions suggested. First and foremost is the rate at which gas can be delivered following nuclear stimulation. Calculations have been made for expected production behavior following a 5-kiloton device and a 40-kiloton device with different permeabilities. These are shown, along with conventional production history. The calculations show that rates of production will be sufficient if costs can be controlled. Costs of nuclear stimulation must be drastically reduced for a commercial process. Project Rulison will cost approximately $3.7 million, excluding lease costs, preliminary tests, and well costs. At such prices, nothing can possibly be commercial; however, these costs can come down in a logical step-wise fashion. Radiation contamination of the gas remains a problem. Three possible solutions to this problem are included. (author)

Economics of nuclear gas stimulation

International Nuclear Information System (INIS)

Frank, G.W.; Coffer, H.F.; Luetkehans, G.R.

1970-01-01

Nuclear stimulation of the Mesaverde Formation in the Piceance Basin appears to be the only available method that can release the contained gas economically. In the Rulison Field alone estimates show six to eight trillion cubic feet of gas may be made available by nuclear means, and possibly one hundred trillion cubic feet could be released in the Piceance Basin. Several problems remain to be solved before this tremendous gas reserve can be tapped. Among these are (1) rates of production following nuclear stimulation; (2) costs of nuclear stimulation; (3) radioactivity of the chimney gas; and (4) development of the ideal type of device to carry out the stimulations. Each of these problems is discussed in detail with possible solutions suggested. First and foremost is the rate at which gas can be delivered following nuclear stimulation. Calculations have been made for expected production behavior following a 5-kiloton device and a 40-kiloton device with different permeabilities. These are shown, along with conventional production history. The calculations show that rates of production will be sufficient if costs can be controlled. Costs of nuclear stimulation must be drastically reduced for a commercial process. Project Rulison will cost approximately $3.7 million, excluding lease costs, preliminary tests, and well costs. At such prices, nothing can possibly be commercial; however, these costs can come down in a logical step-wise fashion. Radiation contamination of the gas remains a problem. Three possible solutions to this problem are included. (author)

Multifocal visual evoked responses to dichoptic stimulation using virtual reality goggles: Multifocal VER to dichoptic stimulation.

Science.gov (United States)

Arvind, Hemamalini; Klistorner, Alexander; Graham, Stuart L; Grigg, John R

2006-05-01

Multifocal visual evoked potentials (mfVEPs) have demonstrated good diagnostic capabilities in glaucoma and optic neuritis. This study aimed at evaluating the possibility of simultaneously recording mfVEP for both eyes with dichoptic stimulation using virtual reality goggles and also to determine the stimulus characteristics that yield maximum amplitude. ten healthy volunteers were recruited and temporally sparse pattern pulse stimuli were presented dichoptically using virtual reality goggles. Experiment 1 involved recording responses to dichoptically presented checkerboard stimuli and also confirming true topographic representation by switching off specific segments. Experiment 2 involved monocular stimulation and comparison of amplitude with Experiment 1. In Experiment 3, orthogonally oriented gratings were dichoptically presented. Experiment 4 involved dichoptic presentation of checkerboard stimuli at different levels of sparseness (5.0 times/s, 2.5 times/s, 1.66 times/s and 1.25 times/s), where stimulation of corresponding segments of two eyes were separated by 16.7, 66.7,116.7 & 166.7 ms respectively. Experiment 1 demonstrated good traces in all regions and confirmed topographic representation. However, there was suppression of amplitude of responses to dichoptic stimulation by 17.9+/-5.4% compared to monocular stimulation. Experiment 3 demonstrated similar suppression between orthogonal and checkerboard stimuli (p = 0.08). Experiment 4 demonstrated maximum amplitude and least suppression (4.8%) with stimulation at 1.25 times/s with 166.7 ms separation between eyes. It is possible to record mfVEP for both eyes during dichoptic stimulation using virtual reality goggles, which present binocular simultaneous patterns driven by independent sequences. Interocular suppression can be almost eliminated by using a temporally sparse stimulus of 1.25 times/s with a separation of 166.7 ms between stimulation of corresponding segments of the two eyes.

Genistein genotoxicity: Critical considerations of in vitro exposure dose

International Nuclear Information System (INIS)

Klein, Catherine B.; King, Audrey A.

2007-01-01

The potential health benefits of soy-derived phytoestrogens include their reported utility as anticarcinogens, cardioprotectants and as hormone replacement alternatives in menopause. Although there is increasing popularity of dietary phytoestrogen supplementation and of vegetarian and vegan diets among adolescents and adults, concerns about potential detrimental or other genotoxic effects persist. While a variety of genotoxic effects of phytoestrogens have been reported in vitro, the concentrations at which such effects occurred were often much higher than the physiologically relevant doses achievable by dietary or pharmacologic intake of soy foods or supplements. This review focuses on in vitro studies of the most abundant soy phytoestrogen, genistein, critically examining dose as a crucial determinant of cellular effects. In consideration of levels of dietary genistein uptake and bioavailability we have defined in vitro concentrations of genistein > 5 μM as non-physiological, and thus 'high' doses, in contrast to much of the previous literature. In doing so, many of the often-cited genotoxic effects of genistein, including apoptosis, cell growth inhibition, topoisomerase inhibition and others become less obvious. Recent cellular, epigenetic and microarray studies are beginning to decipher genistein effects that occur at dietarily relevant low concentrations. In toxicology, the well accepted principle of 'the dose defines the poison' applies to many toxicants and can be invoked, as herein, to distinguish genotoxic versus potentially beneficial in vitro effects of natural dietary products such as genistein

Neurologic Complications of Psychomotor Stimulant Abuse.

Science.gov (United States)

Sanchez-Ramos, Juan

2015-01-01

Psychomotor stimulants are drugs that act on the central nervous system (CNS) to increase alertness, elevate mood, and produce a sense of well-being. These drugs also decrease appetite and the need for sleep. Stimulants can enhance stamina and improve performance in tasks that have been impaired by fatigue or boredom. Approved therapeutic applications of stimulants include attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. These agents also possess potent reinforcing properties that can result in excessive self-administration and abuse. Chronic use is associated with adverse effects including psychosis, seizures, and cerebrovascular accidents, though these complications usually occur in individuals with preexisting risk factors. This chapter reviews the adverse neurologic consequences of chronic psychomotor stimulant use and abuse, with a focus on two prototypical stimulants methamphetamine and cocaine. © 2015 Elsevier Inc. All rights reserved.

Optical stimulation of peripheral nerves in vivo

Science.gov (United States)

Wells, Jonathon D.

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Brain stimulation in migraine.

Science.gov (United States)

Brighina, Filippo; Cosentino, Giuseppe; Fierro, Brigida

2013-01-01

Migraine is a very prevalent disease with great individual disability and socioeconomic burden. Despite intensive research effort in recent years, the etiopathogenesis of the disease remains to be elucidated. Recently, much importance has been given to mechanisms underlying the cortical excitability that has been suggested to be dysfunctional in migraine. In recent years, noninvasive brain stimulation techniques based on magnetic fields (transcranial magnetic stimulation, TMS) and on direct electrical currents (transcranial direct current stimulation, tDCS) have been shown to be safe and effective tools to explore the issue of cortical excitability, activation, and plasticity in migraine. Moreover, TMS, repetitive TMS (rTMS), and tDCS, thanks to their ability to interfere with and/or modulate cortical activity inducing plastic, persistent effects, have been also explored as potential therapeutic approaches, opening an interesting perspective for noninvasive neurostimulation for both symptomatic and preventive treatment of migraine and other types of headache. In this chapter we critically review evidence regarding the role of noninvasive brain stimulation in the pathophysiology and treatment of migraine, delineating the advantages and limits of these techniques together with potential development and future application. © 2013 Elsevier B.V. All rights reserved.

Comparing the force ripple during asynchronous and conventional stimulation.

Science.gov (United States)

Downey, Ryan J; Tate, Mark; Kawai, Hiroyuki; Dixon, Warren E

2014-10-01

Asynchronous stimulation has been shown to reduce fatigue during electrical stimulation; however, it may also exhibit a force ripple. We quantified the ripple during asynchronous and conventional single-channel transcutaneous stimulation across a range of stimulation frequencies. The ripple was measured during 5 asynchronous stimulation protocols, 2 conventional stimulation protocols, and 3 volitional contractions in 12 healthy individuals. Conventional 40 Hz and asynchronous 16 Hz stimulation were found to induce contractions that were as smooth as volitional contractions. Asynchronous 8, 10, and 12 Hz stimulation induced contractions with significant ripple. Lower stimulation frequencies can reduce fatigue; however, they may also lead to increased ripple. Future efforts should study the relationship between force ripple and the smoothness of the evoked movements in addition to the relationship between stimulation frequency and NMES-induced fatigue to elucidate an optimal stimulation frequency for asynchronous stimulation. © 2014 Wiley Periodicals, Inc.

Modulating Hippocampal Plasticity with In Vivo Brain Stimulation

Science.gov (United States)

2016-11-17

wires were left unhooked from stimulation device. Following stimulation , the animals were returned to their homecage until time of euthanasia and...current stimulation (tDCS) to enhance cognitive training: effect of timing of stimulation . Exp Brain Res 232:3345-3351. 15 DISTRIBUTION...AFRL-RH-WP-TR-2016-0082 MODULATING HIPPOCAMPAL PLASTICITY WITH IN-VIVO BRAIN STIMULATION Joyce G. Rohan Oakridge Institute

Addictive drugs and brain stimulation reward.

Science.gov (United States)

Wise, R A

1996-01-01

Direct electrical or chemical stimulation of specific brain regions can establish response habits similar to those established by natural rewards such as food or sexual contact. Cocaine, mu and delta opiates, nicotine, phencyclidine, and cannabis each have actions that summate with rewarding electrical stimulation of the medial forebrain bundle (MFB). The reward-potentiating effects of amphetamine and opiates are associated with central sites of action where these drugs also have their direct rewarding effects, suggesting common mechanisms for drug reward per se and for drug potentiation of brain stimulation reward. The central sites at which these and perhaps other drugs of abuse potentiate brain stimulation reward and are rewarding in their own right are consistent with the hypothesis that the laboratory reward of brain stimulation and the pharmacological rewards of addictive drugs are habit forming because they act in the brain circuits that subserve more natural and biologically significant rewards.

A wireless wearable surface functional electrical stimulator

Science.gov (United States)

Wang, Hai-Peng; Guo, Ai-Wen; Zhou, Yu-Xuan; Xia, Yang; Huang, Jia; Xu, Chong-Yao; Huang, Zong-Hao; Lü, Xiao-Ying; Wang, Zhi-Gong

2017-09-01

In this paper, a wireless wearable functional electrical stimulator controlled by Android phone with real-time-varying stimulation parameters for multichannel surface functional electrical stimulation application has been developed. It can help post-stroke patients using more conveniently. This study focuses on the prototype design, including the specific wristband concept, circuits and stimulation pulse-generation algorithm. A novel stimulator circuit with a driving stage using a complementary current source technique is proposed to achieve a high-voltage compliance, a large output impedance and an accurate linear voltage-to-current conversion. The size of the prototype has been significantly decreased to 17 × 7.5 × 1 cm3. The performance of the prototype has been tested with a loaded resistor and wrist extension/flexion movement of three hemiplegic patients. According to the experiments, the stimulator can generate four-channel charge-balanced biphasic stimulation with a voltage amplitude up to 60 V, and the pulse frequency and width can be adjusted in real time with a range of 100-600 μs and 20-80 Hz, respectively.

High frequency oscillations evoked by peripheral magnetic stimulation.

Science.gov (United States)

Biller, S; Simon, L; Fiedler, P; Strohmeier, D; Haueisen, J

2011-01-01

The analysis of somatosensory evoked potentials (SEP) and / or fields (SEF) is a well-established and important tool for investigating the functioning of the peripheral and central human nervous system. A standard technique to evoke SEPs / SEFs is the stimulation of the median nerve by using a bipolar electrical stimulus. We aim at an alternative stimulation technique enabling stimulation of deep nerve structures while reducing patient stress and error susceptibility. In the current study, we apply a commercial transcranial magnetic stimulation system for peripheral magnetic stimulation of the median nerve. We compare the results of simultaneously recorded EEG signals to prove applicability of our technique to evoke SEPs including low frequency components (LFC) as well as high frequency oscillations (HFO). Therefore, we compare amplitude, latency and time-frequency characteristics of the SEP of 14 healthy volunteers after electric and magnetic stimulation. Both low frequency components and high frequency oscillations were detected. The HFOs were superimposed onto the primary cortical response N20. Statistical analysis revealed significantly lower amplitudes and increased latencies for LFC and HFO components after magnetic stimulation. The differences indicate the inability of magnetic stimulation to elicit supramaximal responses. A psycho-perceptual evaluation showed that magnetic stimulation was less unpleasant for 12 out of the 14 volunteers. In conclusion, we showed that LFC and HFO components related to median nerve stimulation can be evoked by peripheral magnetic stimulation.

Consensus paper: combining transcranial stimulation with neuroimaging

DEFF Research Database (Denmark)

Siebner, Hartwig R; Bergmann, Til O; Bestmann, Sven

2009-01-01

neuroimaging (online approach), TMS can be used to test how focal cortex stimulation acutely modifies the activity and connectivity in the stimulated neuronal circuits. TMS and neuroimaging can also be separated in time (offline approach). A conditioning session of repetitive TMS (rTMS) may be used to induce...... information obtained by neuroimaging can be used to define the optimal site and time point of stimulation in a subsequent experiment in which TMS is used to probe the functional contribution of the stimulated area to a specific task. In this review, we first address some general methodologic issues that need......In the last decade, combined transcranial magnetic stimulation (TMS)-neuroimaging studies have greatly stimulated research in the field of TMS and neuroimaging. Here, we review how TMS can be combined with various neuroimaging techniques to investigate human brain function. When applied during...

Stuttering in Parkinson's disease after deep brain stimulation: A note on dystonia and low-frequency stimulation.

Science.gov (United States)

Mendonça, Marcelo D; Barbosa, Raquel; Seromenho-Santos, Alexandra; Reizinho, Carla; Bugalho, Paulo

2018-04-01

Stuttering, a speech fluency disorder, is a rare complication of Deep Brain Stimulation (DBS) in Parkinson's Disease (PD). We report a 61 years-old patient with PD, afflicted by severe On and Off dystonia, treated with Subthalamic Nucleus DBS that developed post-DBS stuttering while on 130 Hz stimulation. Stuttering reduction was noted when frequency was changed to 80 Hz, but the previously observed dystonia improvement was lost. There are no reports in literature on patients developing stuttering with low-frequency stimulation. We question if low-frequency stimulation could have a role for managing PD's post-DBS stuttering, and notice that stuttering improvement was associated with dystonia worsening suggesting that they are distinct phenomena. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stimulation of hair cells with ultraviolet light

Science.gov (United States)

Azimzadeh, Julien B.; Fabella, Brian A.; Hudspeth, A. J.

2018-05-01

Hair bundles are specialized organelles that transduce mechanical inputs into electrical outputs. To activate hair cells, physiologists have resorted to mechanical methods of hair-bundle stimulation. Here we describe a new method of hair-bundle stimulation, irradiation with ultraviolet light. A hair bundle illuminated by ultraviolet light rapidly moves towards its tall edge, a motion typically associated with excitatory stimulation. The motion disappears upon tip-link rupture and is associated with the opening of mechanotransduction channels. Hair bundles can be induced to move sinusoidally with oscillatory modulation of the stimulation power. We discuss the implications of ultraviolet stimulation as a novel hair-bundle stimulus.

Can the human lumbar posterior columns be stimulated by transcutaneous spinal cord stimulation? A modeling study

OpenAIRE

Danner, Simon M.; Hofstoetter, Ursula S.; Ladenbauer, Josef; Rattay, Frank; Minassian, Karen

2011-01-01

Stimulation of different spinal cord segments in humans is a widely developed clinical practice for modification of pain, altered sensation and movement. The human lumbar cord has become a target for modification of motor control by epidural and more recently by transcutaneous spinal cord stimulation. Posterior columns of the lumbar spinal cord represent a vertical system of axons and when activated can add other inputs to the motor control of the spinal cord than stimulated posterior roots. ...

Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study

OpenAIRE

Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R.

2016-01-01

Background A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-depen...

Computational modeling of epidural cortical stimulation

Science.gov (United States)

Wongsarnpigoon, Amorn; Grill, Warren M.

2008-12-01

Epidural cortical stimulation (ECS) is a developing therapy to treat neurological disorders. However, it is not clear how the cortical anatomy or the polarity and position of the electrode affects current flow and neural activation in the cortex. We developed a 3D computational model simulating ECS over the precentral gyrus. With the electrode placed directly above the gyrus, about half of the stimulus current flowed through the crown of the gyrus while current density was low along the banks deep in the sulci. Beneath the electrode, neurons oriented perpendicular to the cortical surface were depolarized by anodic stimulation, and neurons oriented parallel to the boundary were depolarized by cathodic stimulation. Activation was localized to the crown of the gyrus, and neurons on the banks deep in the sulci were not polarized. During regulated voltage stimulation, the magnitude of the activating function was inversely proportional to the thickness of the CSF and dura. During regulated current stimulation, the activating function was not sensitive to the thickness of the dura but was slightly more sensitive than during regulated voltage stimulation to the thickness of the CSF. Varying the width of the gyrus and the position of the electrode altered the distribution of the activating function due to changes in the orientation of the neurons beneath the electrode. Bipolar stimulation, although often used in clinical practice, reduced spatial selectivity as well as selectivity for neuron orientation.

An Implantable Mixed Analog/Digital Neural Stimulator Circuit

DEFF Research Database (Denmark)

Gudnason, Gunnar; Bruun, Erik; Haugland, Morten

1999-01-01

This paper describes a chip for a multichannel neural stimulator for functional electrical stimulation. The chip performs all the signal processing required in an implanted neural stimulator. The power and signal transmission to the stimulator is carried out via an inductive link. From the signals...... electrical stimulation is to restore various bodily functions (e.g. motor functions) in patients who have lost them due to injury or disease....

Gamma-radiation-induced chromosal aberration in human lymphocytes: dose-rate effects in stimulated and non-stimulated cells

International Nuclear Information System (INIS)

Liniecki, J.; Bajerska, A.; Wyszynska, K.; Cisowska, B.

1977-01-01

Stimulated and non-stimulated human peripheral blood lymphocytes were irradiated acutely and chronically, over 24 h. Dose-effect relationships for dicentric chromosomes were established and various models were fitted to the data. At prolonged irradiations, the yield decreased in basic agreement with the linear-quadratic model of aberration induction. Dose-protraction experiments on PHA + and PHA - lymphocytes, irradiated under various conditions of oxygenation and suspension (culture medium, whole blood) showed that the rejoining time increased from about 3 h in non-stimulated cells to about 10 h after PHA stimulation, and that this retarded rejoining was most likely due to blastic transformation itself and not to other conditions of irradiation

Can the human lumbar posterior columns be stimulated by transcutaneous spinal cord stimulation? A modeling study.

Science.gov (United States)

Danner, Simon M; Hofstoetter, Ursula S; Ladenbauer, Josef; Rattay, Frank; Minassian, Karen

2011-03-01

Stimulation of different spinal cord segments in humans is a widely developed clinical practice for modification of pain, altered sensation, and movement. The human lumbar cord has become a target for modification of motor control by epidural and, more recently, by transcutaneous spinal cord stimulation. Posterior columns of the lumbar spinal cord represent a vertical system of axons and when activated can add other inputs to the motor control of the spinal cord than stimulated posterior roots. We used a detailed three-dimensional volume conductor model of the torso and the McIntyre-Richard-Grill axon model to calculate the thresholds of axons within the posterior columns in response to transcutaneous lumbar spinal cord stimulation. Superficially located large-diameter posterior column fibers with multiple collaterals have a threshold of 45.4 V, three times higher than posterior root fibers (14.1 V). With the stimulation strength needed to activate posterior column axons, posterior root fibers of large and small diameters as well as anterior root fibers are coactivated. The reported results inform on these threshold differences, when stimulation is applied to the posterior structures of the lumbar cord at intensities above the threshold of large-diameter posterior root fibers. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Transcranial Alternating Current Stimulation Attenuates Neuronal Adaptation.

Science.gov (United States)

Kar, Kohitij; Duijnhouwer, Jacob; Krekelberg, Bart

2017-03-01

We previously showed that brief application of 2 mA (peak-to-peak) transcranial currents alternating at 10 Hz significantly reduces motion adaptation in humans. This is but one of many behavioral studies showing that weak currents applied to the scalp modulate neural processing. Transcranial stimulation has been shown to improve perception, learning, and a range of clinical symptoms. Few studies, however, have measured the neural consequences of transcranial current stimulation. We capitalized on the strong link between motion perception and neural activity in the middle temporal (MT) area of the macaque monkey to study the neural mechanisms that underlie the behavioral consequences of transcranial alternating current stimulation. First, we observed that 2 mA currents generated substantial intracranial fields, which were much stronger in the stimulated hemisphere (0.12 V/m) than on the opposite side of the brain (0.03 V/m). Second, we found that brief application of transcranial alternating current stimulation at 10 Hz reduced spike-frequency adaptation of MT neurons and led to a broadband increase in the power spectrum of local field potentials. Together, these findings provide a direct demonstration that weak electric fields applied to the scalp significantly affect neural processing in the primate brain and that this includes a hitherto unknown mechanism that attenuates sensory adaptation. SIGNIFICANCE STATEMENT Transcranial stimulation has been claimed to improve perception, learning, and a range of clinical symptoms. Little is known, however, how transcranial current stimulation generates such effects, and the search for better stimulation protocols proceeds largely by trial and error. We investigated, for the first time, the neural consequences of stimulation in the monkey brain. We found that even brief application of alternating current stimulation reduced the effects of adaptation on single-neuron firing rates and local field potentials; this mechanistic

Modern management of epilepsy: Vagus nerve stimulation.

Science.gov (United States)

Ben-Menachem, E

1996-12-01

Vagus nerve stimulation (VNS) was first tried as a treatment for seizure patients in 1988. The idea to stimulate the vagus nerve and disrupt or prevent seizures was proposed by Jacob Zabarra. He observed a consistent finding among several animal studies which indicated that stimulation of the vagus nerve could alter the brain wave patterns of the animals under study. His hypothesis formed the basis for the development of the vagus nerve stimulator, an implantable device similar to a pacemaker, which is implanted in the left chest and attached to the left vagus nerve via a stimulating lead. Once implanted, the stimulator is programmed by a physician to deliver regular stimulation 24 hours a day regardless of seizure activity. Patients can also activate extra 'on-demand' stimulation with a handheld magnet. Clinical studies have demonstrated VNS therapy to be a safe and effective mode of treatment when added to the existing regimen of severe, refractory patients with epilepsy. Efficacy ranges from seizure free to no response with the majority of patients (> 50%) reporting at least a 50% improvement in number of seizures after 1.5 years of treatment. The side-effect profile is unique and mostly includes stimulation-related sensations in the neck and throat. The mechanism of action for VNS is not clearly understood although two theories have emerged. First, the direct connection theory hypothesizes that the anticonvulsant action of VNS is caused by a threshold raising effect of the connections to the nucleus of the solitary tract and on to other structures. The second is the concept that chronic stimulation of the vagus nerve increases the amount of inhibitory neurotransmitters and decreases the amount of excitatory neurotransmitters. Additional research into the optimal use of VNS is ongoing. Animal and clinical research have produced some interesting new data suggesting there are numerous ways to improve the clinical performance of vagus nerve stimulation as a

Transcranial electrical stimulation accelerates human sleep homeostasis.

Directory of Open Access Journals (Sweden)

Davide Reato

Full Text Available The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO in the human electro-encephalogram (EEG. A computational model of the underlying mechanism predicts that firing rates are predominantly increased during stimulation. Assuming that synaptic homeostasis is driven by average firing rates, we expected an acceleration of synaptic downscaling during stimulation, which is compensated by a reduced drive after stimulation. We show that 25 minutes of transcranial electrical stimulation, as predicted, reduced the decay of SWO in the remainder of the night. Anatomically accurate simulations of the field intensities on human cortex precisely matched the effect size in different EEG electrodes. Together these results suggest a mechanistic link between electrical stimulation and accelerated synaptic homeostasis in human sleep.

Effect of Low-Level Laser Stimulation on EEG

Directory of Open Access Journals (Sweden)

Jih-Huah Wu

2012-01-01

Full Text Available Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

Effect of low-level laser stimulation on EEG.

Science.gov (United States)

Wu, Jih-Huah; Chang, Wen-Dien; Hsieh, Chang-Wei; Jiang, Joe-Air; Fang, Wei; Shan, Yi-Chia; Chang, Yang-Chyuan

2012-01-01

Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG) changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz) to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

Electrical stimulation and motor recovery.

Science.gov (United States)

Young, Wise

2015-01-01

In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as "neurons that fire together, wire together." This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical

Shared Neural Mechanisms for the Evaluation of Intense Sensory Stimulation and Economic Reward, Dependent on Stimulation-Seeking Behavior.

Science.gov (United States)

Norbury, Agnes; Valton, Vincent; Rees, Geraint; Roiser, Jonathan P; Husain, Masud

2016-09-28

Why are some people strongly motivated by intense sensory experiences? Here we investigated how people encode the value of an intense sensory experience compared with economic reward, and how this varies according to stimulation-seeking preference. Specifically, we used a novel behavioral task in combination with computational modeling to derive the value individuals assigned to the opportunity to experience an intense tactile stimulus (mild electric shock). We then examined functional imaging data recorded during task performance to see how the opportunity to experience the sensory stimulus was encoded in stimulation-seekers versus stimulation-avoiders. We found that for individuals who positively sought out this kind of sensory stimulation, there was common encoding of anticipated economic and sensory rewards in the ventromedial prefrontal cortex. Conversely, there was robust encoding of the modeled probability of receiving such stimulation in the insula only in stimulation-avoidant individuals. Finally, we found preliminary evidence that sensory prediction error signals may be positively signed for stimulation-seekers, but negatively signed for stimulation-avoiders, in the posterior cingulate cortex. These findings may help explain why high intensity sensory experiences are appetitive for some individuals, but not for others, and may have relevance for the increased vulnerability for some psychopathologies, but perhaps increased resilience for others, in high sensation-seeking individuals. People vary in their preference for intense sensory experiences. Here, we investigated how different individuals evaluate the prospect of an unusual sensory experience (electric shock), compared with the opportunity to gain a more traditional reward (money). We found that in a subset of individuals who sought out such unusual sensory stimulation, anticipation of the sensory outcome was encoded in the same way as that of monetary gain, in the ventromedial prefrontal cortex

Effect of transcutaneous electrical nerve stimulation induced parotid stimulation on salivary flow

Directory of Open Access Journals (Sweden)

Sreenivasulu Pattipati

2013-01-01

Full Text Available Aims and Objectives: The main objective of this study was to evaluate the duration of stimulation over the parotid salivary flow following the use of transcutaneous electric nerve stimulation (TENS in different age groups. Materials and Methods: The study was carried out in three different age groups. Under group A individuals from 21 to 35 years of age, group B 36-50 years and group C above 51 years were considered. In each group 30 subjects were taken of whom 15 were males and 15 were females. The placement of pads was approximated bilaterally over the parotid glands. The working parameters of TENS unit were fixed at 50 Hz and the unit was in normal mode. Results: Subjects belonging to group B were showing statistically significant increases in the duration of stimulated parotid salivary flow following the use of TENS. Conclusion: TENS can be considered as a non-pharmacological alternative to improve salivation for longer period in xerostomia patients.

Theory of multichannel magnetic stimulation: toward functional neuromuscular rehabilitation.

Science.gov (United States)

Ruohonen, J; Ravazzani, P; Grandori, F; Ilmoniemi, R J

1999-06-01

Human excitable cells can be stimulated noninvasively with externally applied time-varying electromagnetic fields. The stimulation can be achieved either by directly driving current into the tissue (electrical stimulation) or by means of electro-magnetic induction (magnetic stimulation). While the electrical stimulation of the peripheral neuromuscular system has many beneficial applications, peripheral magnetic stimulation has so far only a few. This paper analyzes theoretically the use of multiple magnetic stimulation coils to better control the excitation and also to eventually mimic electrical stimulation. Multiple coils allow electronic spatial adjustment of the shape and location of the stimulus without moving the coils. The new properties may enable unforeseen uses for peripheral magnetic stimulation, e.g., in rehabilitation of patients with neuromuscular impairment.

[Electrical acupoint stimulation increases athletes' rapid strength].

Science.gov (United States)

Yang, Hua-yuan; Liu, Tang-yi; Kuai, Le; Gao, Ming

2006-05-01

To search for a stimulation method for increasing athletes' performance. One hundred and fifty athletes were randomly divided into a trial group and a control group, 75 athletes in each group. Acupoints were stimulated with audio frequency pulse modulated wave and multi-blind method were used to investigate effects of the electric stimulation of acupoints on 30-meter running, standing long jumping and Cybex isokinetic testing index. The acupoint electric stimulation method could significantly increase athlete's performance (P < 0.05), and the biomechanical indexes, maximal peak moment of force (P < 0.05), force moment accelerating energy (P < 0.05) and average power (P < 0.05). Electrical acupoint stimulation can enhance athlete's rapid strength.

A Chip for an Implantable Neural Stimulator

DEFF Research Database (Denmark)

Gudnason, Gunnar; Bruun, Erik; Haugland, Morten

2000-01-01

This paper describes a chip for a multichannel neural stimulator for functional electrical stimulation (FES). The purpose of FES is to restore muscular control in disabled patients. The chip performs all the signal processing required in an implanted neural stimulator. The power and digital data...

Subliminal Stimulation: Hoax or Reality?

Science.gov (United States)

Trank, Douglas M.

Subliminal stimulation is defined as that which is perceived by an individual below the threshold of awareness or cognizance. This article traces the history of research in subliminal stimulation to illustrate that under certain circumstances and conditions, this behavioral phenomenon does occur. Although subliminal stimuli do affect human…

Optimal number of stimulation contacts for coordinated reset neuromodulation

Directory of Open Access Journals (Sweden)

Borys eLysyansky

2013-07-01

Full Text Available In this computational study we investigatecoordinated reset (CR neuromodulation designed for an effective controlof synchronization by multi-site stimulation of neuronal target populations. This method was suggested to effectively counteract pathological neuronal synchronycharacteristic for several neurological disorders. We studyhow many stimulation sites are required for optimal CR-induced desynchronization. We found that a moderate increase of the number of stimulation sitesmay significantly prolong the post-stimulation desynchronized transientafter the stimulation is completely switched off. This can, in turn,reduce the amount of the administered stimulation current for theintermittent ON-OFF CR stimulation protocol, where time intervalswith stimulation ON are recurrently followed by time intervals withstimulation OFF. In addition, we found that the optimal number ofstimulation sites essentially depends on how strongly the administeredcurrent decays within the neuronal tissue with increasing distancefrom the stimulation site. In particular, for a broad spatial stimulationprofile, i.e., for a weak spatial decay rate of the stimulation current,CR stimulation can optimally be delivered via a small number of stimulationsites. Our findings may contribute to an optimization of therapeutic applications of CR neuromodulation.

Geothermal Reservoir Well Stimulation Program: technology transfer

Energy Technology Data Exchange (ETDEWEB)

1980-05-01

Each of the following types of well stimulation techniques are summarized and explained: hydraulic fracturing; thermal; mechanical, jetting, and drainhole drilling; explosive and implosive; and injection methods. Current stimulation techniques, stimulation techniques for geothermal wells, areas of needed investigation, and engineering calculations for various techniques. (MHR)

Determination of stimulation focality in heterogeneous head models during transcranial magnetic stimulation (TMS)

Science.gov (United States)

Lee, Erik; Hadimani, Ravi; Jiles, David

2015-03-01

Transcranial Magnetic Stimulation (TMS) is an increasingly popular tool used by both the scientific and medical community to understand and treat the brain. TMS has the potential to help people with a wide range of diseases such as Parkinson's, Alzheimer's, and PTSD, while currently being used to treat people with chronic, drug-resistant depression. Through computer simulations, we are able to see the electric field that TMS induces in anatomical human models, but there is no measure to quantify this electric field in a way that relates to a specific patient undergoing TMS therapy. We propose a way to quantify the focality of the induced electric field in a heterogeneous head model during TMS by relating the surface area of the brain being stimulated to the total volume of the brain being stimulated. This figure would be obtained by conducting finite element analysis (FEA) simulations of TMS therapy on a patient specific head model. Using this figure to assist in TMS therapy will allow clinicians and researchers to more accurately stimulate the desired region of a patient's brain and be more equipped to do comparative studies on the effects of TMS across different patients. This work was funded by the Carver Charitable Trust.

Gamma radiation induced chromosal aberration in human lymphocytes: dose-rate effects in stimulated and non-stimulated cells

Energy Technology Data Exchange (ETDEWEB)

Liniecki, J; Bajerska, A; Wyszynska, K [School of Medicine, Lodz (Poland). Div. of Nuclear Medicine and Radiobiology. Medical Research Center; Cisowska, B [Copernicus Municipal Hospital, Lodz (Poland). Oncology Center. Radiotherapy Dept.

1977-05-01

Stimulated and non-stimulated human peripheral blood lymphocytes were irradiated acutely and chronically, over 24 h. Dose-effect relationships for dicentric chromosomes were established and various models were fitted to the data. At prolonged irradiations, the yield decreased in basic agreement with the linear-quadratic model of aberration induction. Dose-protraction experiments on PHA/sup +/ and PHA/sup -/ lymphocytes, irradiated under various conditions of oxygenation and suspension (culture medium, whole blood) showed that the rejoining time increased from about 3 h in non-stimulated cells to about 10 h after PHA stimulation, and that this retarded rejoining was most likely due to blastic transformation itself and not to other conditions of irradiation.

Bursting behaviours in cascaded stimulated Brillouin scattering

International Nuclear Information System (INIS)

Liu Zhan-Jun; He Xian-Tu; Zheng Chun-Yang; Wang Yu-Gang

2012-01-01

Stimulated Brillouin scattering is studied by numerically solving the Vlasov—Maxwell system. A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma. It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light, as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction. The bursting time in the reflectivity is found to be less than half the ion acoustic period. The ion temperature can affect the stimulated Brillouin scattering cascade, which can repeat several times at low ion temperatures and can be completely eliminated at high ion temperatures. For stimulated Brillouin scattering saturation, higher-harmonic generation and wave—wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter. In addition, stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light. (physics of gases, plasmas, and electric discharges)

Coupling brain-machine interfaces with cortical stimulation for brain-state dependent stimulation: enhancing motor cortex excitability for neurorehabilitation

Directory of Open Access Journals (Sweden)

Alireza eGharabaghi

2014-03-01

Full Text Available Motor recovery after stroke is an unsolved challenge despite intensive rehabilitation training programs. Brain stimulation techniques have been explored in addition to traditional rehabilitation training to increase the excitability of the stimulated motor cortex. This modulation of cortical excitability augments the response to afferent input during motor exercises, thereby enhancing skilled motor learning by long-term potentiation-like plasticity. Recent approaches examined brain stimulation applied concurrently with voluntary movements to induce more specific use-dependent neural plasticity during motor training for neurorehabilitation. Unfortunately, such approaches are not applicable for the many severely affected stroke patients lacking residual hand function. These patients require novel activity-dependent stimulation paradigms based on intrinsic brain activity. Here, we report on such brain state-dependent stimulation (BSDS combined with haptic feedback provided by a robotic hand orthosis. Transcranial magnetic stimulation of the motor cortex and haptic feedback to the hand were controlled by sensorimotor desynchronization during motor-imagery and applied within a brain-machine interface environment in one healthy subject and one patient with severe hand paresis in the chronic phase after stroke. BSDS significantly increased the excitability of the stimulated motor cortex in both healthy and post-stroke conditions, an effect not observed in non-BSDS protocols. This feasibility study suggests that closing the loop between intrinsic brain state, cortical stimulation and haptic feedback provides a novel neurorehabilitation strategy for stroke patients lacking residual hand function, a proposal that warrants further investigation in a larger cohort of stroke patients.

Stimulating Language: Insights from TMS

Science.gov (United States)

Devlin, Joseph T.; Watkins, Kate E.

2007-01-01

Fifteen years ago, Pascual-Leone and colleagues used transcranial magnetic stimulation (TMS) to investigate speech production in pre-surgical epilepsy patients and in doing so, introduced a novel tool into language research. TMS can be used to non-invasively stimulate a specific cortical region and transiently disrupt information processing. These…

New stimulation regimens: endogenous and exogenous progesterone use to block the LH surge during ovarian stimulation for IVF.

Science.gov (United States)

Massin, Nathalie

2017-03-01

The advent of embryo and oocyte vitrification today gives reproductive specialists an opportunity to consider new strategies for improving the practice and results of IVF attempts. As the freezing of entire cohorts does not compromise, and may even improve, the results of IVF attempts, it is possible to break away from the standard sequence of stimulation-retrieval-transfer. The constraints associated with ovarian stimulation in relation to the potential harmful effects of the hormonal environment on endometrial receptivity can be avoided. This review will look at the new stimulation protocols where progesterone is used to block the LH surge. Thanks to 'freeze all' strategies, the increase in progesterone could actually be no longer a cause for concern. There are two ways of using progesterone, whether it be endogenous, as in luteal phase stimulation, or exogenous, as in the use of progesterone in the follicular phase i.e. progestin primed ovarian stimulation. A literature search was carried out (until September 2016) on MEDLINE. The following text words were utilized to generate the list of citations: progestin primed ovarian stimulation, luteal phase stimulation, luteal stimulation, duostim, double stimulation, random start. Articles and their references were then examined in order to identify other potential studies. All of the articles are reported in this review. The use of progesterone during ovarian stimulation is effective in blocking the LH surge, whether endogenous or exogenous, and it does not affect the number of oocytes collected or the quality of the embryos obtained. Its main constraint is that it requires total freezing and delayed transfer. A variety of stimulation protocols can be derived from these two methods, and their implications are discussed, from fertility preservation to ovarian response profiles to organization for the patients and clincs. These new regimens enable more flexibility and are of emerging interest in daily practice. However

Studies in dosimetry using stimulated exoelectron emission

International Nuclear Information System (INIS)

Petel, Maurice.

1976-06-01

Some applications of the stimulated exoelectron emission in radiation dosimetry are discussed. The principles which govern the phenomenon are presented. The apparatus, in particular the counter, used to monitor the emission is discussed with reference to both optical and thermal stimulation. The correlation existing between thermoluminescence and thermally stimulated exoelectron emission were studied in both lithium fluoride and aluminium oxide. Furthermore, aluminium oxides from different sources were examined, and one of these, chosen to investigate the dosimetric properties of this material using both methods of stimulation [fr

Particle trapping in stimulated scattering processes

International Nuclear Information System (INIS)

Karttunen, S.J.; Heikkinen, J.A.

1981-01-01

Particle trapping effects on stimulated Brillouin and Raman scattering are investigated. A time and space dependent model assumes a Maxwellian plasma which is taken to be homogeneous in the interaction region. Ion trapping has a rather weak effect on stimulated Brillouin scattering and large reflectivities are obtained even in strong trapping regime. Stimulated Raman scattering is considerably reduced by electron trapping. Typically 15-20 times larger laser intensities are required to obtain same reflectivity levels than without trapping. (author)

Memory and convulsive stimulation: effects of stimulus waveform.

Science.gov (United States)

Spanis, C W; Squire, L R

1981-09-01

Electrical stimulation with brief pulses can produce a seizure requiring less energy than conventional sine-wave stimulation, and it has been suggested that brief-pulse stimulation might reduce the memory loss associated with electroconvulsive therapy (ECT). The authors evaluated the effects of electroconvulsive shock (ECS) on memory in mice by using various waveforms, current intensities, training-ECS intervals, pulse widths, and stimulus durations. When equated for ability to produce seizures, low-energy, brief-pulse stimulation caused as much amnesia as sine-wave stimulation and sometimes more. In the absence of comparisons of the amnesic effects of brief-pulse and sine-wave stimulation in humans, the use of brief pulses for administering ECT is unwarranted.

The safety of transcranial magnetic stimulation with deep brain stimulation instruments.

Science.gov (United States)

Shimojima, Yoshio; Morita, Hiroshi; Nishikawa, Noriko; Kodaira, Minori; Hashimoto, Takao; Ikeda, Shu-Ichi

2010-02-01

Transcranial magnetic stimulation (TMS) has been employed in patients with an implanted deep brain stimulation (DBS) device. We investigated the safety of TMS using simulation models with an implanted DBS device. The DBS lead was inserted into plastic phantoms filled with dilute gelatin showing impedance similar to that of human brain. TMS was performed with three different types of magnetic coil. During TMS (1) electrode movement, (2) temperature change around the lead, and (3) TMS-induced current in various situations were observed. The amplitude and area of each evoked current were measured to calculate charge density of the evoked current. There was no movement or temperature increase during 0.2 Hz repetitive TMS with 100% stimulus intensity for 1 h. The size of evoked current linearly increased with TMS intensity. The maximum charge density exceeded the safety limit of 30 muC/cm(2)/phase during stimulation above the loops of the lead with intensity over 50% using a figure-eight coil. Strong TMS on the looped DBS leads should not be administered to avoid electrical tissue injury. Subcutaneous lead position should be paid enough attention for forthcoming situations during surgery. Copyright 2009 Elsevier Ltd. All rights reserved.

Numerical dosimetry of transcranial magnetic stimulation coils

Science.gov (United States)

Crowther, Lawrence; Hadimani, Ravi; Jiles, David

2014-03-01

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique capable of stimulating neurons by means of electromagnetic induction. TMS can be used to map brain function and shows promise for the diagnosis and treatment of neurological and psychiatric disorders. Calculation of fields induced in the brain are necessary to accurately identify stimulated neural tissue during TMS. This allows the development of novel TMS coil designs capable of stimulating deeper brain regions and increasing the localization of stimulation that can be achieved. We have performed numerical calculations of magnetic and electric field with high-resolution anatomically realistic human head models to find these stimulated brain regions for a variety of proposed TMS coil designs. The realistic head models contain heterogeneous tissue structures and electrical conductivities, yielding superior results to those obtained from the simplified homogeneous head models that are commonly employed. The attenuation of electric field as a function of depth in the brain and the localization of stimulating field have been methodically investigated. In addition to providing a quantitative comparison of different TMS coil designs the variation of induced field between subjects has been investigated. We also show the differences in induced fields between adult, adolescent and child head models to preemptively identify potential safety issues in the application of pediatric TMS.

Imaging transcranial direct current stimulation (tDCS) of the prefrontal cortex-correlation or causality in stimulation-mediated effects?

Science.gov (United States)

Wörsching, Jana; Padberg, Frank; Ertl-Wagner, Birgit; Kumpf, Ulrike; Kirsch, Beatrice; Keeser, Daniel

2016-10-01

Transcranial current stimulation approaches include neurophysiologically distinct non-invasive brain stimulation techniques widely applied in basic, translational and clinical research: transcranial direct current stimulation (tDCS), oscillating transcranial direct current stimulation (otDCS), transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). Prefrontal tDCS seems to be an especially promising tool for clinical practice. In order to effectively modulate relevant neural circuits, systematic research on prefrontal tDCS is needed that uses neuroimaging and neurophysiology measures to specifically target and adjust this method to physiological requirements. This review therefore analyses the various neuroimaging methods used in combination with prefrontal tDCS in healthy and psychiatric populations. First, we provide a systematic overview on applications, computational models and studies combining neuroimaging or neurophysiological measures with tDCS. Second, we categorise these studies in terms of their experimental designs and show that many studies do not vary the experimental conditions to the extent required to demonstrate specific relations between tDCS and its behavioural or neurophysiological effects. Finally, to support best-practice tDCS research we provide a methodological framework for orientation among experimental designs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stimulation Technologies for Deep Well Completions

Energy Technology Data Exchange (ETDEWEB)

Stephen Wolhart

2005-06-30

The Department of Energy (DOE) is sponsoring the Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies conducted a study to evaluate the stimulation of deep wells. The objective of the project was to review U.S. deep well drilling and stimulation activity, review rock mechanics and fracture growth in deep, high-pressure/temperature wells and evaluate stimulation technology in several key deep plays. This report documents results from this project.

Vagus Nerve Stimulation for Treating Epilepsy

Science.gov (United States)

... and their FAMILIES VAGUS NERVE STIMULATION FOR TREATING EPILEPSY This information sheet is provided to help you ... how vagus nerve stimulation (VNS) may help treat epilepsy. The American Academy of Neurology (AAN) is the ...

andrographis paniculata Nees, andrographolide, HPLC

Directory of Open Access Journals (Sweden)

Anni Nurliani

2012-02-01

Full Text Available It has been conducted a study of identify population of spermatogenic cells of mice after induction Durian (Durio zibethinus Murr. bark extract. This research used completely randomized design with five treatments i.e. control without treatment; control with aquadest; 5% durian bark extract; 10%; and 20% with five repetitions for each treatment. Extract was given per oral in volume dose of 0,5 ml/ 25–30 g/BW per day during 36 days. The result of this study showed that durian bark extracts caused significantly decrease of population of spermatogenic cells in concentrate 5%, 10%, and 20%.

Non-invasive brain stimulation and computational models in post-stroke aphasic patients: single session of transcranial magnetic stimulation and transcranial direct current stimulation. A randomized clinical trial

Directory of Open Access Journals (Sweden)

Michele Devido dos Santos

2017-11-01

Full Text Available ABSTRACT CONTEXT AND OBJECTIVE: Patients undergoing the same neuromodulation protocol may present different responses. Computational models may help in understanding such differences. The aims of this study were, firstly, to compare the performance of aphasic patients in naming tasks before and after one session of transcranial direct current stimulation (tDCS, transcranial magnetic stimulation (TMS and sham, and analyze the results between these neuromodulation techniques; and secondly, through computational model on the cortex and surrounding tissues, to assess current flow distribution and responses among patients who received tDCS and presented different levels of results from naming tasks. DESIGN AND SETTING: Prospective, descriptive, qualitative and quantitative, double blind, randomized and placebo-controlled study conducted at Faculdade de Ciências Médicas da Santa Casa de São Paulo. METHODS: Patients with aphasia received one session of tDCS, TMS or sham stimulation. The time taken to name pictures and the response time were evaluated before and after neuromodulation. Selected patients from the first intervention underwent a computational model stimulation procedure that simulated tDCS. RESULTS: The results did not indicate any statistically significant differences from before to after the stimulation.The computational models showed different current flow distributions. CONCLUSIONS: The present study did not show any statistically significant difference between tDCS, TMS and sham stimulation regarding naming tasks. The patients’responses to the computational model showed different patterns of current distribution.

Brain stimulation methods to treat tobacco addiction.

Science.gov (United States)

Wing, Victoria C; Barr, Mera S; Wass, Caroline E; Lipsman, Nir; Lozano, Andres M; Daskalakis, Zafiris J; George, Tony P

2013-05-01

Tobacco smoking is the leading cause of preventable deaths worldwide, but many smokers are simply unable to quit. Psychosocial and pharmaceutical treatments have shown modest results on smoking cessation rates, but there is an urgent need to develop treatments with greater efficacy. Brain stimulation methods are gaining increasing interest as possible addiction therapeutics. The purpose of this paper is to review the studies that have evaluated brain stimulation techniques on tobacco addiction, and discuss future directions for research in this novel area of addiction interventions. Electronic and manual literature searches identified fifteen studies that administered repetitive transcranial magnetic stimulation (rTMS), cranial electrostimulation (CES), transcranial direct current stimulation (tDCS) or deep brain stimulation (DBS). rTMS was found to be the most well studied method with respect to tobacco addiction. Results indicate that rTMS and tDCS targeted to the dorsolateral prefrontal cortex (DLPFC) were the most efficacious in reducing tobacco cravings, an effect that may be mediated through the brain reward system involved in tobacco addiction. While rTMS was shown to reduce consumption of cigarettes, as yet no brain stimulation technique has been shown to significantly increase abstinence rates. It is possible that the therapeutic effects of rTMS and tDCS may be improved by optimization of stimulation parameters and increasing the duration of treatment. Although further studies are needed to confirm the ability of brain stimulation methods to treat tobacco addiction, this review indicates that rTMS and tDCS both represent potentially novel treatment modalities. Copyright © 2013 Elsevier Inc. All rights reserved.

Evoked Electromyographically Controlled Electrical Stimulation

Directory of Open Access Journals (Sweden)

Mitsuhiro Hayashibe

2016-07-01

Full Text Available Time-variant muscle responses under electrical stimulation (ES are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications.Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES are also well known source of time-varying characteristics coming from muscle response under ES. Therefore it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favour of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

Geothermal Reservoir Well Stimulation Program: technology transfer

Energy Technology Data Exchange (ETDEWEB)

1980-05-01

A literature search on reservoir and/or well stimulation techniques suitable for application in geothermal fields is presented. The literature on stimulation techniques in oil and gas field applications was also searched and evaluated as to its relevancy to geothermal operations. The equivalent low-temperature work documented in the open literature is cited, and an attempt is made to evaluate the relevance of this information as far as high-temperature stimulation work is concerned. Clays play an important role in any stimulation work. Therefore, special emphasis has been placed on clay behavior anticipated in geothermal operations. (MHR)

Follicle-stimulating hormone (FSH) blood test

Science.gov (United States)

... ency/article/003710.htm Follicle-stimulating hormone (FSH) blood test To use the sharing features on this page, please enable JavaScript. The follicle stimulating hormone (FSH) blood test measures the level of FSH in blood. FSH ...

Aromatase inhibitors in stimulated IVF cycles

DEFF Research Database (Denmark)

Papanikolaou, Evangelos G; Polyzos, Nikolaos P; Al Humaidan, Peter Samir Heskjær

2011-01-01

are available regarding their efficacy in IVF stimulated cycles. Current available evidence support that letrozole may have a promising role in stimulated IVF cycles, either when administered during the follicular phase for ovarian stimulation. Especially for women with poor ovarian response, letrozole appears...... to have the potential to increase clinical pregnancy rates when combined with gonadotropins, whereas at the same time reduces the total gonadotropin dose required for ovarian stimulation. However, given that in all of the trials letrozole has been administered in GnRH antagonist cycles, it is intriguing...... to test in the future how it may perform when used in GnRH agonist cycles. Finally administration of letrozole during luteal phase in IVF cycles offers another treatment modality for patients at high risk for OHSS taking into account that it drastically reduces estradiol levels....

Stimulation Efficiency With Decaying Exponential Waveforms in a Wirelessly Powered Switched-Capacitor Discharge Stimulation System.

Science.gov (United States)

Lee, Hyung-Min; Howell, Bryan; Grill, Warren M; Ghovanloo, Maysam

2018-05-01

The purpose of this study was to test the feasibility of using a switched-capacitor discharge stimulation (SCDS) system for electrical stimulation, and, subsequently, determine the overall energy saved compared to a conventional stimulator. We have constructed a computational model by pairing an image-based volume conductor model of the cat head with cable models of corticospinal tract (CST) axons and quantified the theoretical stimulation efficiency of rectangular and decaying exponential waveforms, produced by conventional and SCDS systems, respectively. Subsequently, the model predictions were tested in vivo by activating axons in the posterior internal capsule and recording evoked electromyography (EMG) in the contralateral upper arm muscles. Compared to rectangular waveforms, decaying exponential waveforms with time constants >500 μs were predicted to require 2%-4% less stimulus energy to activate directly models of CST axons and 0.4%-2% less stimulus energy to evoke EMG activity in vivo. Using the calculated wireless input energy of the stimulation system and the measured stimulus energies required to evoke EMG activity, we predict that an SCDS implantable pulse generator (IPG) will require 40% less input energy than a conventional IPG to activate target neural elements. A wireless SCDS IPG that is more energy efficient than a conventional IPG will reduce the size of an implant, require that less wireless energy be transmitted through the skin, and extend the lifetime of the battery in the external power transmitter.

Validating computationally predicted TMS stimulation areas using direct electrical stimulation in patients with brain tumors near precentral regions.

Science.gov (United States)

Opitz, Alexander; Zafar, Noman; Bockermann, Volker; Rohde, Veit; Paulus, Walter

2014-01-01

The spatial extent of transcranial magnetic stimulation (TMS) is of paramount interest for all studies employing this method. It is generally assumed that the induced electric field is the crucial parameter to determine which cortical regions are excited. While it is difficult to directly measure the electric field, one usually relies on computational models to estimate the electric field distribution. Direct electrical stimulation (DES) is a local brain stimulation method generally considered the gold standard to map structure-function relationships in the brain. Its application is typically limited to patients undergoing brain surgery. In this study we compare the computationally predicted stimulation area in TMS with the DES area in six patients with tumors near precentral regions. We combine a motor evoked potential (MEP) mapping experiment for both TMS and DES with realistic individual finite element method (FEM) simulations of the electric field distribution during TMS and DES. On average, stimulation areas in TMS and DES show an overlap of up to 80%, thus validating our computational physiology approach to estimate TMS excitation volumes. Our results can help in understanding the spatial spread of TMS effects and in optimizing stimulation protocols to more specifically target certain cortical regions based on computational modeling.

Immediate effect of laryngeal surface electrical stimulation on swallowing performance.

Science.gov (United States)

Takahashi, Keizo; Hori, Kazuhiro; Hayashi, Hirokazu; Fujiu-Kurachi, Masako; Ono, Takahiro; Tsujimura, Takanori; Magara, Jin; Inoue, Makoto

2018-01-01

Surface electrical stimulation of the laryngeal region is used to improve swallowing in dysphagic patients. However, little is known about how electrical stimulation affects tongue movements and related functions. We investigated the effect of electrical stimulation on tongue pressure and hyoid movement, as well as suprahyoid and infrahyoid muscle activity, in 18 healthy young participants. Electrical stimulation (0.2-ms duration, 80 Hz, 80% of each participant's maximal tolerance) of the laryngeal region was applied. Each subject swallowed 5 ml of barium sulfate liquid 36 times at 10-s intervals. During the middle 2 min, electrical stimulation was delivered. Tongue pressure, electromyographic activity of the suprahyoid and infrahyoid muscles, and videofluorographic images were simultaneously recorded. Tongue pressure during stimulation was significantly lower than before or after stimulation and was significantly greater after stimulation than at baseline. Suprahyoid activity after stimulation was larger than at baseline, while infrahyoid muscle activity did not change. During stimulation, the position of the hyoid at rest was descended, the highest hyoid position was significantly inferior, and the vertical movement was greater than before or after stimulation. After stimulation, the positions of the hyoid at rest and at the maximum elevation were more superior than before stimulation. The deviation of the highest positions of the hyoid before and after stimulation corresponded to the differences in tongue pressures at those times. These results suggest that surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. NEW & NOTEWORTHY Surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. Tongue muscles may contribute to overshot recovery

21 CFR 882.5830 - Implanted diaphragmatic/phrenic nerve stimulator.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted diaphragmatic/phrenic nerve stimulator... Implanted diaphragmatic/phrenic nerve stimulator. (a) Identification. An implanted diaphragmatic/phrenic nerve stimulator is a device that provides electrical stimulation of a patient's phrenic nerve to...

Oligofructose stimulates calcium absorption in adolescents

NARCIS (Netherlands)

Heuvel, E.G.H.M. van den; Muys, T.; Dokkum, W. van; Schaafsma, G.

1999-01-01

Background: In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects. Objective: The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents. Design:

Evaluation of Galvanic Vestibular Stimulation System

Science.gov (United States)

Kofman, I. S.; Warren, E.; DeSoto, R.; Moroney, G.; Chastain, J.; De Dios, Y. E.; Gadd, N.; Taylor, L.; Peters, B. T.; Allen, E.;

Partially non-linear stimulation intensity-dependent effects of direct current stimulation on motor cortex excitability in humans.

Science.gov (United States)

Batsikadze, G; Moliadze, V; Paulus, W; Kuo, M-F; Nitsche, M A

2013-04-01

Transcranial direct current stimulation (tDCS) of the human motor cortex at an intensity of 1 mA with an electrode size of 35 cm(2) has been shown to induce shifts of cortical excitability during and after stimulation. These shifts are polarity-specific with cathodal tDCS resulting in a decrease and anodal stimulation in an increase of cortical excitability. In clinical and cognitive studies, stronger stimulation intensities are used frequently, but their physiological effects on cortical excitability have not yet been explored. Therefore, here we aimed to explore the effects of 2 mA tDCS on cortical excitability. We applied 2 mA anodal or cathodal tDCS for 20 min on the left primary motor cortex of 14 healthy subjects. Cathodal tDCS at 1 mA and sham tDCS for 20 min was administered as control session in nine and eight healthy subjects, respectively. Motor cortical excitability was monitored by transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) from the right first dorsal interosseous muscle. Global corticospinal excitability was explored via single TMS pulse-elicited MEP amplitudes, and motor thresholds. Intracortical effects of stimulation were obtained by cortical silent period (CSP), short latency intracortical inhibition (SICI) and facilitation (ICF), and I wave facilitation. The above-mentioned protocols were recorded both before and immediately after tDCS in randomized order. Additionally, single-pulse MEPs, motor thresholds, SICI and ICF were recorded every 30 min up to 2 h after stimulation end, evening of the same day, next morning, next noon and next evening. Anodal as well as cathodal tDCS at 2 mA resulted in a significant increase of MEP amplitudes, whereas 1 mA cathodal tDCS decreased corticospinal excitability. A significant shift of SICI and ICF towards excitability enhancement after both 2 mA cathodal and anodal tDCS was observed. At 1 mA, cathodal tDCS reduced single-pulse TMS-elicited MEP amplitudes and shifted SICI

Short-Term Dosage Regimen for Stimulation-Induced Long-Lasting Desynchronization

Directory of Open Access Journals (Sweden)

Thanos Manos

2018-04-01

Full Text Available In this paper, we computationally generate hypotheses for dose-finding studies in the context of desynchronizing neuromodulation techniques. Abnormally strong neuronal synchronization is a hallmark of several brain disorders. Coordinated Reset (CR stimulation is a spatio-temporally patterned stimulation technique that specifically aims at disrupting abnormal neuronal synchrony. In networks with spike-timing-dependent plasticity CR stimulation may ultimately cause an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and neuronal synchrony. This long-lasting desynchronization was theoretically predicted and verified in several pre-clinical and clinical studies. We have shown that CR stimulation with rapidly varying sequences (RVS robustly induces an anti-kindling at low intensities e.g., if the CR stimulation frequency (i.e., stimulus pattern repetition rate is in the range of the frequency of the neuronal oscillation. In contrast, CR stimulation with slowly varying sequences (SVS turned out to induce an anti-kindling more strongly, but less robustly with respect to variations of the CR stimulation frequency. Motivated by clinical constraints and inspired by the spacing principle of learning theory, in this computational study we propose a short-term dosage regimen that enables a robust anti-kindling effect of both RVS and SVS CR stimulation, also for those parameter values where RVS and SVS CR stimulation previously turned out to be ineffective. Intriguingly, for the vast majority of parameter values tested, spaced multishot CR stimulation with demand-controlled variation of stimulation frequency and intensity caused a robust and pronounced anti-kindling. In contrast, spaced CR stimulation with fixed stimulation parameters as well as singleshot CR stimulation of equal integral duration failed to improve the stimulation outcome. In the model network under consideration, our short-term dosage regimen enables to robustly induce

Short-Term Dosage Regimen for Stimulation-Induced Long-Lasting Desynchronization.

Science.gov (United States)

Manos, Thanos; Zeitler, Magteld; Tass, Peter A

2018-01-01

In this paper, we computationally generate hypotheses for dose-finding studies in the context of desynchronizing neuromodulation techniques. Abnormally strong neuronal synchronization is a hallmark of several brain disorders. Coordinated Reset (CR) stimulation is a spatio-temporally patterned stimulation technique that specifically aims at disrupting abnormal neuronal synchrony. In networks with spike-timing-dependent plasticity CR stimulation may ultimately cause an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and neuronal synchrony. This long-lasting desynchronization was theoretically predicted and verified in several pre-clinical and clinical studies. We have shown that CR stimulation with rapidly varying sequences (RVS) robustly induces an anti-kindling at low intensities e.g., if the CR stimulation frequency (i.e., stimulus pattern repetition rate) is in the range of the frequency of the neuronal oscillation. In contrast, CR stimulation with slowly varying sequences (SVS) turned out to induce an anti-kindling more strongly, but less robustly with respect to variations of the CR stimulation frequency. Motivated by clinical constraints and inspired by the spacing principle of learning theory, in this computational study we propose a short-term dosage regimen that enables a robust anti-kindling effect of both RVS and SVS CR stimulation, also for those parameter values where RVS and SVS CR stimulation previously turned out to be ineffective. Intriguingly, for the vast majority of parameter values tested, spaced multishot CR stimulation with demand-controlled variation of stimulation frequency and intensity caused a robust and pronounced anti-kindling. In contrast, spaced CR stimulation with fixed stimulation parameters as well as singleshot CR stimulation of equal integral duration failed to improve the stimulation outcome. In the model network under consideration, our short-term dosage regimen enables to robustly induce long

Transcranial Magnetic Stimulation-coil design with improved focality

Science.gov (United States)

Rastogi, P.; Lee, E. G.; Hadimani, R. L.; Jiles, D. C.

2017-05-01

Transcranial Magnetic Stimulation (TMS) is a technique for neuromodulation that can be used as a non-invasive therapy for various neurological disorders. In TMS, a time varying magnetic field generated from an electromagnetic coil placed on the scalp is used to induce an electric field inside the brain. TMS coil geometry plays an important role in determining the focality and depth of penetration of the induced electric field responsible for stimulation. Clinicians and basic scientists are interested in stimulating a localized area of the brain, while minimizing the stimulation of surrounding neural networks. In this paper, a novel coil has been proposed, namely Quadruple Butterfly Coil (QBC) with an improved focality over the commercial Figure-8 coil. Finite element simulations were conducted with both the QBC and the conventional Figure-8 coil. The two coil's stimulation profiles were assessed with 50 anatomically realistic MRI derived head models. The coils were positioned on the vertex and the scalp over the dorsolateral prefrontal cortex to stimulate the brain. Computer modeling of the coils has been done to determine the parameters of interest-volume of stimulation, maximum electric field, location of maximum electric field and area of stimulation across all 50 head models for both coils.

A multi-channel stimulator and electrode array providing a rotating current whirlpool for electrical stimulation of wounds.

Science.gov (United States)

Petrofsky, J; Suh, H J; Fish, A; Hernandez, V; Abdo, A; Collins, K; Mendoza, E; Yang, T-N

2008-01-01

When electrical stimulation is used on wounds, the electrical current has difficulty penetrating areas where there is necrotic tissue. Further, for an irregularly shaped wound, current distribution is poor in some areas of the wound since conventional two-electrode delivery systems provide the greatest current in a line directly between the electrodes. A new stimulator and electrode system is described which uses three electrodes spaced around a wound to disperse current more evenly. The stimulator senses tissue impedance and then redirects current by altering its Thevenin's output impedance for each electrode; each of the three electrodes becomes the active one in sequence while the remaining are the sink electrodes. Eight subjects were examined to test the stimulator. Electrical stimulation was applied to the skin above the quadriceps muscle at currents of 15 mA in six subjects without wounds and in two subjects with wounds. The relationship between electrode position and current dispersion on the skin was examined with a two-electrode vs. a three-electrode system to set stimulation parameters for the computer. The results showed that the three-electrode system could (1) detect areas of the skin with high impedance; (2) compensate by altering the Thevenin's output impedance at each of the three electrodes to shift current to high impedance areas; (3) provide uniform current across the skin as assessed by skin current and blood flow measurements with a laser Doppler flow imager.

Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

Directory of Open Access Journals (Sweden)

H Nikukar

2014-05-01

We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis.  Keywords:  Mesenchymal, Nanoscale, Stem Cells.

Medical back belt with integrated neuromuscular electrical stimulation

NARCIS (Netherlands)

Bottenberg, E. (Eliza); Brinks, G.J. (Ger); Hesse, J. (Jenny)

2014-01-01

The medical back belt with integrated neuromuscular electrical stimulation is anorthopedic device, which has two main functions. The first function is to stimulate the backmuscles by using a neuromuscular electrical stimulation device that releases regular,electrical impulses. The second function of

Stimulation Technologies for Deep Well Completions

Energy Technology Data Exchange (ETDEWEB)

None

2003-09-30

The Department of Energy (DOE) is sponsoring the Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies is conducting a study to evaluate the stimulation of deep wells. The objective of the project is to assess U.S. deep well drilling & stimulation activity, review rock mechanics & fracture growth in deep, high pressure/temperature wells and evaluate stimulation technology in several key deep plays. An assessment of historical deep gas well drilling activity and forecast of future trends was completed during the first six months of the project; this segment of the project was covered in Technical Project Report No. 1. The second progress report covers the next six months of the project during which efforts were primarily split between summarizing rock mechanics and fracture growth in deep reservoirs and contacting operators about case studies of deep gas well stimulation.

Transcranial Direct Current Stimulation in Epilepsy.

Science.gov (United States)

San-Juan, Daniel; Morales-Quezada, León; Orozco Garduño, Adolfo Josué; Alonso-Vanegas, Mario; González-Aragón, Maricarmen Fernández; Espinoza López, Dulce Anabel; Vázquez Gregorio, Rafael; Anschel, David J; Fregni, Felipe

2015-01-01

Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation therapy in epilepsy with conflicting results in terms of efficacy and safety. Review the literature about the efficacy and safety of tDCS in epilepsy in humans and animals. We searched studies in PubMed, MedLine, Scopus, Web of Science and Google Scholar (January 1969 to October 2013) using the keywords 'transcranial direct current stimulation' or 'tDCS' or 'brain polarization' or 'galvanic stimulation' and 'epilepsy' in animals and humans. Original articles that reported tDCS safety and efficacy in epileptic animals or humans were included. Four review authors independently selected the studies, extracted data and assessed the methodological quality of the studies using the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions, PRISMA guidelines and Jadad Scale. A meta-analysis was not possible due to methodological, clinical and statistical heterogeneity of included studies. We analyzed 9 articles with different methodologies (3 animals/6 humans) with a total of 174 stimulated individuals; 109 animals and 65 humans. In vivo and in vitro animal studies showed that direct current stimulation can successfully induce suppression of epileptiform activity without neurological injury and 4/6 (67%) clinical studies showed an effective decrease in epileptic seizures and 5/6 (83%) reduction of inter-ictal epileptiform activity. All patients tolerated tDCS well. tDCS trials have demonstrated preliminary safety and efficacy in animals and patients with epilepsy. Further larger studies are needed to define the best stimulation protocols and long-term follow-up. Copyright © 2015 Elsevier Inc. All rights reserved.

The Mechanism of Financial Stimulation of Investment Activity

Directory of Open Access Journals (Sweden)

Vasiliy Valeryevich Tarakanov

2016-03-01

Full Text Available Modernization of the Russian economy and creation of conditions for its economic growth demand activization of investment activity that is possible by means of its financial stimulation. Financial stimulation of investment activity defines the need of changes of the contents, the directions and ways of implementation of the financial relations between subjects of investment activity. Financial stimulation of investment activity is carried out via the mechanism in the context of which these financial relations are settled. For defining the mechanism of financial stimulation of investment activity the authors consider the very concept of financial mechanism. The conclusion is drawn that all elements of the financial mechanism are the integrated unity, they are interdependent and interconnected, and the combination of types, forms, methods of the organization of the financial relations forms “a design of the financial mechanism”. The article specifies the maintenance of the mechanism of financial stimulation of investment activity, and reveals its essence. The structure of the mechanism of financial stimulation of investment activity is presented by the following elements: subjects of financial stimulation of investment activity, the purpose of attraction of investments by them, set of financial methods and tools, sources of means of achievement of goals, standard - legal and information support of financial stimulation of investment activity. It is proved that in the mechanism of financial stimulation of investment activity the leading role is played by the state by means of forms of direct and indirect participation in attraction of investments, each of which is realized by means of specific methods and the corresponding tools. The widespread instrument of financial stimulation of investment activity is the investments which are carried out by the state institutes of development participating in the organization of the process of financial

GABAB Receptor Stimulation Accentuates the Locomotor Effects of Morphine in Mice Bred for Extreme Sensitivity to the Stimulant Effects of Ethanol

OpenAIRE

Holstein, Sarah E.; Phillips, Tamara J.

2006-01-01

Mice selectively bred for divergent sensitivity to the locomotor stimulant effects of ethanol (FAST and SLOW) also differ in their locomotor response to morphine. The GABAB receptor has been implicated in the mediation of locomotor stimulation to both ethanol and morphine, and a reduction in ethanol-induced stimulation has been found with the GABAB receptor agonist baclofen in FAST mice. We hypothesized that GABAB receptor activation would also attenuate the locomotor stimulant responses to m...

Stimulation of entorhinal cortex-dentate gyrus circuitry is antidepressive.

Science.gov (United States)

Yun, Sanghee; Reynolds, Ryan P; Petrof, Iraklis; White, Alicia; Rivera, Phillip D; Segev, Amir; Gibson, Adam D; Suarez, Maiko; DeSalle, Matthew J; Ito, Naoki; Mukherjee, Shibani; Richardson, Devon R; Kang, Catherine E; Ahrens-Nicklas, Rebecca C; Soler, Ivan; Chetkovich, Dane M; Kourrich, Saïd; Coulter, Douglas A; Eisch, Amelia J

2018-04-16

Major depressive disorder (MDD) is considered a 'circuitopathy', and brain stimulation therapies hold promise for ameliorating MDD symptoms, including hippocampal dysfunction. It is unknown whether stimulation of upstream hippocampal circuitry, such as the entorhinal cortex (Ent), is antidepressive, although Ent stimulation improves learning and memory in mice and humans. Here we show that molecular targeting (Ent-specific knockdown of a psychosocial stress-induced protein) and chemogenetic stimulation of Ent neurons induce antidepressive-like effects in mice. Mechanistically, we show that Ent-stimulation-induced antidepressive-like behavior relies on the generation of new hippocampal neurons. Thus, controlled stimulation of Ent hippocampal afferents is antidepressive via increased hippocampal neurogenesis. These findings emphasize the power and potential of Ent glutamatergic afferent stimulation-previously well-known for its ability to influence learning and memory-for MDD treatment.

Effects of Navigated Repetitive Transcranial Magnetic Stimulation After Stroke.

Science.gov (United States)

Chervyakov, Alexander V; Poydasheva, Alexandra G; Lyukmanov, Roman H; Suponeva, Natalia A; Chernikova, Ludmila A; Piradov, Michael A; Ustinova, Ksenia I

2018-03-01

The purpose of this study was to test the effects of navigated repetitive transcranial magnetic stimulation, delivered in different modes, on motor impairments and functional limitations after stroke. The study sample included 42 patients (58.5 ± 10.7 years; 26 males) who experienced a single unilateral stroke (1-12 months previously) in the area of the middle cerebral artery. Patients completed a course of conventional rehabilitation, together with 10 sessions of navigated repetitive transcranial magnetic stimulation or sham stimulation. Stimulation was scheduled five times a week over two consecutive weeks in an inpatient clinical setting. Patients were randomly assigned to one of four groups and received sham stimulation (n = 10), low-frequency (1-Hz) stimulation of the nonaffected hemisphere (n = 11), high-frequency (10-Hz) stimulation of the affected hemisphere (n = 13), or sequential combination of low- and high-frequency stimulations (n = 8). Participants were evaluated before and after stimulation with clinical tests, including the arm and hand section of the Fugl-Meyer Assessment Scale, modified Ashworth Scale of Muscle Spasticity, and Barthel Index of Activities of Daily Living. Participants in the three groups receiving navigated repetitive transcranial magnetic stimulation showed improvements in arm and hand functions on the Fugl-Meyer Stroke Assessment Scale. Ashworth Scale of Muscle Spasticity and Barthel Index scores were significantly reduced in groups receiving low- or high-frequency stimulation alone. Including navigated repetitive transcranial magnetic stimulation in a conventional rehabilitation program positively influenced motor and functional recovery in study participants, demonstrating the clinical potential of the method. The results of this study will be used for designing a large-scale clinical trial.

Manual evaluation of residual curarization using double burst stimulation

DEFF Research Database (Denmark)

Drenck, N E; Ueda, N; Olsen, Niels Vidiendal

1989-01-01

Double burst stimulation (DBS) is a new mode of stimulation developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists of two short bursts of 50 Hz tetanic stimulation, separated by 750 ms, and the response to the stimulation is two short muscle contracti......Double burst stimulation (DBS) is a new mode of stimulation developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists of two short bursts of 50 Hz tetanic stimulation, separated by 750 ms, and the response to the stimulation is two short muscle...... contractions. Fade in the response results from neuromuscular blockade as with train-of-four stimulation (TOF). The authors compared the sensitivity of DBS and TOF in the detection of residual neuromuscular blockade during clinical anaesthesia. Fifty-two healthy patients undergoing surgery were studied...... with DBS than with TOF, regardless of the TOF ratio level. Absence of fade with TOF implied a 48% chance of considerable residual relaxation as compared with 9% when fade was absent with DBS. The results demonstrate that DBS is more sensitive than TOF in the manual detection of residual neuromuscular...

Radioimmunoassay for thyroid-stimulating hormone (TSH)

International Nuclear Information System (INIS)

Blakemore, J.I.; Lewin, N.; Burgett, M.W.

1978-01-01

This invention provides a method for the radioimmunoassay of thyroid-stimulating hormone which utilizes a rapid and convenient version of a double antibody procedure. Highly purified second antibody is bound, by means of covalent bonds, to hydrolyzed polyacrylamide particles to produce a two-phase system. The solid phase comprises immobilized second antibody bound to the reaction product of labeled and unlabeled thyroid-stimulating hormone with the first antibody (first antibody-antigen complex) and the liquid phase comprises free (unbound) labeled and unlabeled thyroid-stimulating hormone. The two phases are separated and the radioactivity of either phase is measured

Spinal cord stimulation for neuropathic pain: current perspectives

Directory of Open Access Journals (Sweden)

Wolter T

2014-11-01

Full Text Available Tilman Wolter Interdisciplinary Pain Centre, University Hospital Freiburg, Freiburg, Germany Abstract: Neuropathic pain constitutes a significant portion of chronic pain. Patients with neuropathic pain are usually more heavily burdened than patients with nociceptive pain. They suffer more often from insomnia, anxiety, and depression. Moreover, analgesic medication often has an insufficient effect on neuropathic pain. Spinal cord stimulation constitutes a therapy alternative that, to date, remains underused. In the last 10 to 15 years, it has undergone constant technical advancement. This review gives an overview of the present practice of spinal cord stimulation for chronic neuropathic pain and current developments such as high-frequency stimulation and peripheral nerve field stimulation. Keywords: spinal cord stimulation, neuropathic pain, neurostimulation

Closing the loop of deep brain stimulation

Science.gov (United States)

Carron, Romain; Chaillet, Antoine; Filipchuk, Anton; Pasillas-Lépine, William; Hammond, Constance

2013-01-01

High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment. PMID:24391555

Closing the loop of deep brain stimulation.

Science.gov (United States)

Carron, Romain; Chaillet, Antoine; Filipchuk, Anton; Pasillas-Lépine, William; Hammond, Constance

2013-12-20

High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.

Closing the loop of deep brain stimulation

Directory of Open Access Journals (Sweden)

Romain eCARRON

2013-12-01

Full Text Available High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfils these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.

In vivo charge injection limits increased after 'unsafe' stimulation

DEFF Research Database (Denmark)

Meijs, Suzan; Sørensen, Søren; Rechendorff, Kristian

2015-01-01

was not observed with any of the stimulation protocols and no tissue damage was observed for the 20 mA – 200 Hz stimulation group. This indicates that the ‘safe potential window’ may not be applicable in vivo, as no damage was done stimulating with 20 mA at 200 Hz, while damage was done using the same current......The effect of unsafe stimulation on charge injection limits (Qinj) and pulsing capacitance (Cpulse) was investigated. Four stimulation protocols were applied: 20 mA – 200 and 400 Hz, 50 mA – 200 and 400 Hz. Increasing Qinj and Cpulse were observed for all stimulation protocols. Corrosion...

Optimized temporal pattern of brain stimulation designed by computational evolution.

Science.gov (United States)

Brocker, David T; Swan, Brandon D; So, Rosa Q; Turner, Dennis A; Gross, Robert E; Grill, Warren M

2017-01-04

Brain stimulation is a promising therapy for several neurological disorders, including Parkinson's disease. Stimulation parameters are selected empirically and are limited to the frequency and intensity of stimulation. We varied the temporal pattern of deep brain stimulation to ameliorate symptoms in a parkinsonian animal model and in humans with Parkinson's disease. We used model-based computational evolution to optimize the stimulation pattern. The optimized pattern produced symptom relief comparable to that from standard high-frequency stimulation (a constant rate of 130 or 185 Hz) and outperformed frequency-matched standard stimulation in a parkinsonian rat model and in patients. Both optimized and standard high-frequency stimulation suppressed abnormal oscillatory activity in the basal ganglia of rats and humans. The results illustrate the utility of model-based computational evolution of temporal patterns to increase the efficiency of brain stimulation in treating Parkinson's disease and thereby reduce the energy required for successful treatment below that of current brain stimulation paradigms. Copyright © 2017, American Association for the Advancement of Science.

Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

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Hao Yu Choo

Full Text Available Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera. A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs, flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%, rapid response time (< 1.0 s, and small variation (< 0.33 s; indicating little habituation. Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.

Role of sound stimulation in reprogramming brain connectivity.

Science.gov (United States)

Chaudhury, Sraboni; Nag, Tapas C; Jain, Suman; Wadhwa, Shashi

2013-09-01

Sensory stimulation has a critical role to play in the development of an individual. Environmental factors tend to modify the inputs received by the sensory pathway. The developing brain is most vulnerable to these alterations and interacts with the environment to modify its neural circuitry. In addition to other sensory stimuli, auditory stimulation can also act as external stimuli to provide enrichment during the perinatal period. There is evidence that suggests that enriched environment in the form of auditory stimulation can play a substantial role in modulating plasticity during the prenatal period. This review focuses on the emerging role of prenatal auditory stimulation in the development of higher brain functions such as learning and memory in birds and mammals. The molecular mechanisms of various changes in the hippocampus following sound stimulation to effect neurogenesis, learning and memory are described. Sound stimulation can also modify neural connectivity in the early postnatal life to enhance higher cognitive function or even repair the secondary damages in various neurological and psychiatric disorders. Thus, it becomes imperative to examine in detail the possible ameliorating effects of prenatal sound stimulation in existing animal models of various psychiatric disorders, such as autism.

Facilitate insight by non-invasive brain stimulation.

Directory of Open Access Journals (Sweden)

Richard P Chi

Full Text Available Our experiences can blind us. Once we have learned to solve problems by one method, we often have difficulties in generating solutions involving a different kind of insight. Yet there is evidence that people with brain lesions are sometimes more resistant to this so-called mental set effect. This inspired us to investigate whether the mental set effect can be reduced by non-invasive brain stimulation. 60 healthy right-handed participants were asked to take an insight problem solving task while receiving transcranial direct current stimulation (tDCS to the anterior temporal lobes (ATL. Only 20% of participants solved an insight problem with sham stimulation (control, whereas 3 times as many participants did so (p = 0.011 with cathodal stimulation (decreased excitability of the left ATL together with anodal stimulation (increased excitability of the right ATL. We found hemispheric differences in that a stimulation montage involving the opposite polarities did not facilitate performance. Our findings are consistent with the theory that inhibition to the left ATL can lead to a cognitive style that is less influenced by mental templates and that the right ATL may be associated with insight or novel meaning. Further studies including neurophysiological imaging are needed to elucidate the specific mechanisms leading to the enhancement.

CYTOLOGICAL CHARACTERIZATION OF PREMEIOTIC VERSUS POSTMEIOTIC DEFECTS PRODUCING HYBRID MALE STERILITY AMONG SIBLING SPECIES OF THE DROSOPHILA MELANOGASTER COMPLEX.

Science.gov (United States)

Kulathinal, Rob; Singh, Rama S

1998-08-01

In accordance with Haldane's rule, hybridizations between species of the Drosophila simulans clade produce fertile females but sterile males. In this study, a comprehensive characterization was undertaken on the six types of F 1 males that were the result of the crosses between D. simulans, D. sechellia, and D. mauritiana. With the use of light and electron microscopy, it was shown that while each particular hybrid genotype exhibited a specific sterility phenotype, these phenotypes fell into two distinct classes. The two hybrid genotypes that possessed D. mauritiana X-chromosomes contained spermatogenic defects that caused arrests in premeiotic spermatogenic stages. The other four F 1 hybrids possessed postmeiotic spermatogenic defects. Nonsynchronous cell divisions, underdeveloped mitochondrial derivative-axonemal associations, and microtubule abnormalities were common to all of these hybrids. Each particular postmeiotically defective hybrid genotype demonstrated characteristically distinct profiles in sperm bundle number in addition to characteristic spermiogenic arrests in the furthest developed spermatids. These results in species hybrids contrast with the absence of significant differences in spermatogenic characters between species of this clade. In addition, by utilizing an attached-X cross, we investigated the influence of maternal effects and cytoplasmic factors on the sterility of D. simulans F 1 hybrids and found none. However, we discovered a strain of D. simulans (2119) that caused a large shift in sterility from postmeiotic to premeiotic when crossed to D. sechellia. This suggests that D. simulans is polymorphic for genes involving premeiotic and postmeiotic sterility and that the two types of sterilities between species may have a simple genetic basis. © 1998 The Society for the Study of Evolution.

Transcranial alternating current stimulation (tACS

Directory of Open Access Journals (Sweden)

Andrea eAntal

2013-06-01

Full Text Available Transcranial alternating current stimulation (tACS seems likely to open a new era of the field of noninvasive electrical stimulation of the human brain by directly interfering with cortical rhythms. It is expected to synchronize (by one single resonance frequency or desynchronize (e.g. by the application of several frequencies cortical oscillations. If applied long enough it may cause neuroplastic effects. In the theta range it may improve cognition when applied in phase. Alpha rhythms could improve motor performance, whereas beta intrusion may deteriorate them. TACS with both alpha and beta frequencies has a high likelihood to induce retinal phosphenes. Gamma intrusion can possibly interfere with attention. Stimulation in the ripple range induces intensity dependent inhibition or excitation in the motor cortex most likely by entrainment of neuronal networks, whereas stimulation in the low kHz range induces excitation by neuronal membrane interference. TACS in the 200 kHz range may have a potential in oncology.

Effect of Parkinson's Disease in Transcranial Magnetic Stimulation Treatment

Science.gov (United States)

Syeda, Farheen; Magsood, Hamzah; Lee, Erik; El-Gendy, Ahmed; Jiles, David; Hadimani, Ravi

Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

Stimulation of phagocytosis by sulforaphane

International Nuclear Information System (INIS)

Suganuma, Hiroyuki; Fahey, Jed W.; Bryan, Kelley E.; Healy, Zachary R.; Talalay, Paul

2011-01-01

Research highlights: → Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. → This effect does not require Nrf2-dependent induction of phase 2 genes. → Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-μm diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2 -/- mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

Stimulation of phagocytosis by sulforaphane

Energy Technology Data Exchange (ETDEWEB)

Suganuma, Hiroyuki, E-mail: hsuganu1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Fahey, Jed W., E-mail: jfahey@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Bryan, Kelley E., E-mail: kbryanm1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Healy, Zachary R., E-mail: zhealy1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Talalay, Paul, E-mail: ptalalay@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

2011-02-04

Research highlights: {yields} Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. {yields} This effect does not require Nrf2-dependent induction of phase 2 genes. {yields} Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-{mu}m diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2{sup -/-} mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

Evaluation of the effectiveness of transcranial direct current stimulation (tDCS) and psychosensory stimulation through DOCS scale in a minimally conscious subject.

Science.gov (United States)

Dimitri, Danilo; De Filippis, Daniela; Galetto, Valentina; Zettin, Marina

2017-04-01

The aim of our study was to assess the effectiveness of transcranial direct current stimulation (tDCS) on alertness improvement in a patient in a minimally conscious state (MCS) by means of disorders of consciousness scale combined with psycho-sensory stimulation. The effects of tDCS on muscle hypertonia through the Ashworth scale were also examined. tDCS was performed through a two-channel intra-cephalic stimulator. After stimulation, the patient followed a psychosensory stimulation training. Results pointed out an increase in DOCunit score, as well as an increase in alertness maintenance and an improvement in muscle hypertonia, although a MCS state persisted.

Transcranial magnetic stimulation in schizophrenia.

Science.gov (United States)

Zaman, Rashid; Thind, Dilraj; Kocmur, Marga

2008-11-01

Transcranial magnetic stimulation (TMS) is a non-invasive and painless way of stimulating the neural tissue (cerebral cortex, spinal roots, and cranial and peripheral nerves). The first attempts at stimulating the neural tissue date back to 1896 by d'Arsonval; however, it was successfully carried out by Barker and colleagues in Sheffield, UK, in 1985. It soon became a useful tool in neuroscience for neurophysiologists and neurologists and psychiatrists. The original single-pulse TMS, largely used as an investigative tool, was further refined and developed in the early 1990s into what is known as repetitive TMS (rTMS), having a frequency range of 1-60 Hz. The stimulation by both TMS and rTMS of various cortical regions displayed alteration of movement, mood, and behavior, leading researchers to investigate a number of psychiatric and neuropsychiatric disorders, as well as to explore its therapeutic potential. There is now a large amount of literature on the use of TMS/rTMS in depression; however, its use in schizophrenia, both as an investigative and certainly as a therapeutic tool is relatively recent with a limited but increasing number of publications. In this article, we will outline the principles of TMS/rTMS and critically review their use in schizophrenia both as investigative and potential therapeutic tools.

Inhibition of in vitro growth and arrest in the G0/G1 phase of HCT8 line human colon cancer cells by kaempferide triglycoside from Dianthus caryophyllus.

Science.gov (United States)

Martineti, Valentina; Tognarini, Isabella; Azzari, Chiara; Carbonell Sala, Silvia; Clematis, Francesca; Dolci, Marcello; Lanzotti, Virginia; Tonelli, Francesco; Brandi, Maria Luisa; Curir, Paolo

2010-09-01

The effects of phytoestrogens have been studied in the hypothalamic-pituitary-gonadal axis and in various non-gonadal targets. Epidemiologic and experimental evidence indicates a protective effect of phytoestrogens also in colorectal cancer. The mechanism through which estrogenic molecules control colorectal cancer tumorigenesis could possibly involve estrogen receptor beta, the predominantly expressed estrogen receptor subtype in colon mucosa.To validate this hypothesis, we therefore used an engineered human colon cancer cell line induced to overexpress estrogen receptor beta, beside its native cell line, expressing very low levels of ERbeta and not expressing ERalpha; as a phytoestrogenic molecule, we used kaempferide triglycoside, a glycosylated flavonol from a Dianthus caryophyllus cultivar. The inhibitory properties of this molecule toward vegetal cell growth have been previously demonstrated: however, no data on its activity on animal cell or information about the mechanism of this activity are available. Kaempferide triglycoside proved to inhibit the proliferation of native and estrogen receptor beta overexpressing colon cancer cells through a mechanism not mediated by ligand binding dependent estrogen receptor activation. It affected HCT8 cell cycle progression by increasing the G(0)/G(1) cell fraction and in estrogen receptor beta overexpressing cells increased two antioxidant enzymes. Interestingly, the biological effects of this kaempferide triglycoside were strengthened by the presence of high levels of estrogen receptor beta.Pleiotropic molecular effects of phytoestrogens may explain their protective activity against colorectal cancer and may represent an interesting area for future investigation with potential clinical applications. Copyright 2010 John Wiley & Sons, Ltd.

Prescription stimulant use is associated with earlier onset of psychosis.

Science.gov (United States)

Moran, Lauren V; Masters, Grace A; Pingali, Samira; Cohen, Bruce M; Liebson, Elizabeth; Rajarethinam, R P; Ongur, Dost

2015-12-01

A childhood history of attention deficit hyperactivity disorder (ADHD) is common in psychotic disorders, yet prescription stimulants may interact adversely with the physiology of these disorders. Specifically, exposure to stimulants leads to long-term increases in dopamine release. We therefore hypothesized that individuals with psychotic disorders previously exposed to prescription stimulants will have an earlier onset of psychosis. Age of onset of psychosis (AOP) was compared in individuals with and without prior exposure to prescription stimulants while controlling for potential confounding factors. In a sample of 205 patients recruited from an inpatient psychiatric unit, 40% (n = 82) reported use of stimulants prior to the onset of psychosis. Most participants were prescribed stimulants during childhood or adolescence for a diagnosis of ADHD. AOP was significantly earlier in those exposed to stimulants (20.5 vs. 24.6 years stimulants vs. no stimulants, p drugs of abuse, and family history of a first-degree relative with psychosis, the association between stimulant exposure and earlier AOP remained significant. There was a significant gender × stimulant interaction with a greater reduction in AOP for females, whereas the smaller effect of stimulant use on AOP in males did not reach statistical significance. In conclusion, individuals with psychotic disorders exposed to prescription stimulants had an earlier onset of psychosis, and this relationship did not appear to be mediated by IQ or cannabis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stimulant use among secondary school students in Osogbo, Nigeria.

Science.gov (United States)

Eegunranti, B A; Fatoye, F O; Morakinyo, O

2009-09-01

The objectives of this study were to determine the prevalence and pattern of stimulant use and its association with 'brain fag syndrome' among secondary school students in Osogbo, Osun State. The study also aimed to determine the association of socio-demographic variables (of the students and their parents) with stimulant use. A questionnaire consisting of sociodemographic variables, the stimulant use section of the WHO Student Drug Use Questionnaire and the Brain Fag Syndrome Scale (BFSS) was administered on randomly selected students of the two Local Government Areas of Osogbo. The prevalence rates of stimulant use were calculated and the association of stimulant use with Brain Fag Syndrome (BFS) and socio-demographic variables was determined. The 30-day prevalence rate of stimulant use was 20.3%. Users engaged more in the use of common and cheap stimulants (coffee and kola nut). Majority of users started at age 13 years or below. There was a very high relationship between stimulant use and the symptoms of the BFS (pfather and the description of mother as being too permissive. The findings suggest the need to increase the awareness of the dangers of stimulant use among students. Control programmes are urgently needed to prevent student wastage.

Systems for deep brain stimulation: review of technical features.

Science.gov (United States)

Amon, A; Alesch, F

2017-09-01

The use of deep brain stimulation (DBS) is an important treatment option for movement disorders and other medical conditions. Today, three major manufacturers provide implantable systems for DBS. Although the underlying principle is basically the same for all available systems, the differences in the technical features vary considerably. This article outlines aspects regarding the technical features of DBS systems. The differences between voltage and current sources are addressed and their effect on stimulation is shown. To maintain clinical benefit and minimize side effects the stimulation field has to be adapted to the requirements of the patient. Shaping of the stimulation field can be achieved by the electrode design and polarity configuration. Furthermore, the electric signal consisting of stimulation rate, stimulation amplitude and pulse width affect the stimulation field. Interleaving stimulation is an additional concept, which permits improved treatment outcomes. Therefore, the electrode design, the polarity, the electric signal, and the concept of interleaving stimulation are presented. The investigated systems can be also categorized as rechargeable and non-rechargeable, which is briefly discussed. Options for interconnecting different system components from various manufacturers are presented. The present paper summarizes the technical features and their combination possibilities, which can have a major impact on the therapeutic effect.

Clinical Applications of Transcranial Magnetic Stimulation in Pediatric Neurology.

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Narayana, Shalini; Papanicolaou, Andrew C; McGregor, Amy; Boop, Frederick A; Wheless, James W

2015-08-01

Noninvasive brain stimulation is now an accepted technique that is used as a diagnostic aid and in the treatment of neuropsychiatric disorders in adults, and is being increasingly used in children. In this review, we will discuss the basic principles and safety of one noninvasive brain stimulation method, transcranial magnetic stimulation. Improvements in the spatial accuracy of transcranial magnetic stimulation are described in the context of image-guided transcranial magnetic stimulation. The article describes and provides examples of the current clinical applications of transcranial magnetic stimulation in children as an aid in the diagnosis and treatment of neuropsychiatric disorders and discusses future potential applications. Transcranial magnetic stimulation is a noninvasive tool that is safe for use in children and adolescents for functional mapping and treatment, and for many children it aids in the preoperative evaluation and the risk-benefit decision making. © The Author(s) 2014.

Performance Enhancement by Brain Stimulation

Directory of Open Access Journals (Sweden)

Parisa Gazerani

2017-09-01

Full Text Available Number of substances and strategies are available to increase performance in sport (Catlin and Murray, 1996. Since 2004, the World Anti-Doping Agency (WADA posts an updated list of substances and methods prohibited to athletes. Drugs (e.g., steroids, stimulants are a major part of this list; however, technologies and methods (e.g., gene doping are increasingly being identified and added (WADA, 2017. Among technologies and methods that might exert a potential effect on athletic performance, brain stimulation has recently been subjected to extensive discussion. Neuro-enhancement for doping purposes has been termed “neurodoping” in the literature (Davis, 2013; however, this concept needs further documentation before the term “neurodoping” can be used properly. Two major non-invasive techniques of brain stimulations are transcranial magnetic stimulation (TMS (Hallett, 2007; Rossi et al., 2009, and transcranial direct current stimulation (tDCS (Stagg and Nitsche, 2011. In TMS, an electric coil held over the head applies magnetic pulses to create currents in the brain. In tDCS, a low, continuous electrical current is delivered to the brain by using surface electrodes attached on the scalp. TMS and tDCS have been used in both research and clinic (Shin and Pelled, 2017 for example to examine alterations in cognitive function or motor skills or to assist in recovering motor function after a stroke (Gomez Palacio Schjetnan et al., 2013 or reducing fatigue in patients with multiple sclerosis (Saiote et al., 2014. In an opinion paper, it was proposed that use of emerging brain stimulation techniques might also enhance physical and mental performance in sports (Davis, 2013. The assumption was based on several reports. For example some studies have shown that TMS could shorten reaction times to visual, auditory and touch stimuli, reduce tremor, and enhance the acquisition of complex motor skills. Based on the current evidence, a recent review (Colzato

21 CFR 890.5860 - Ultrasound and muscle stimulator.

Science.gov (United States)

2010-04-01

..., muscle spasms, and joint contractures, but not for the treatment of malignancies. The device also passes... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasound and muscle stimulator. 890.5860 Section... Ultrasound and muscle stimulator. (a) Ultrasound and muscle stimulator for use in applying therapeutic deep...

Adaptive deep brain stimulation in advanced Parkinson disease.

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Little, Simon; Pogosyan, Alex; Neal, Spencer; Zavala, Baltazar; Zrinzo, Ludvic; Hariz, Marwan; Foltynie, Thomas; Limousin, Patricia; Ashkan, Keyoumars; FitzGerald, James; Green, Alexander L; Aziz, Tipu Z; Brown, Peter

2013-09-01

Brain-computer interfaces (BCIs) could potentially be used to interact with pathological brain signals to intervene and ameliorate their effects in disease states. Here, we provide proof-of-principle of this approach by using a BCI to interpret pathological brain activity in patients with advanced Parkinson disease (PD) and to use this feedback to control when therapeutic deep brain stimulation (DBS) is delivered. Our goal was to demonstrate that by personalizing and optimizing stimulation in real time, we could improve on both the efficacy and efficiency of conventional continuous DBS. We tested BCI-controlled adaptive DBS (aDBS) of the subthalamic nucleus in 8 PD patients. Feedback was provided by processing of the local field potentials recorded directly from the stimulation electrodes. The results were compared to no stimulation, conventional continuous stimulation (cDBS), and random intermittent stimulation. Both unblinded and blinded clinical assessments of motor effect were performed using the Unified Parkinson's Disease Rating Scale. Motor scores improved by 66% (unblinded) and 50% (blinded) during aDBS, which were 29% (p = 0.03) and 27% (p = 0.005) better than cDBS, respectively. These improvements were achieved with a 56% reduction in stimulation time compared to cDBS, and a corresponding reduction in energy requirements (p random intermittent stimulation. BCI-controlled DBS is tractable and can be more efficient and efficacious than conventional continuous neuromodulation for PD. Copyright © 2013 American Neurological Association.

Facilitating Access to Emotions: Neural Signature of EMDR Stimulation

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Herkt, Deborah; Tumani, Visal; Grön, Georg; Kammer, Thomas; Hofmann, Arne; Abler, Birgit

2014-01-01

Background Eye Movement Desensitisation and Reprocessing (EMDR) is a method in psychotherapy effective in treating symptoms of posttraumatic stress disorder. The client attends to alternating bilateral visual, auditory or sensory stimulation while confronted with emotionally disturbing material. It is thought that the bilateral stimulation as a specific element of EMDR facilitates accessing and processing of negative material while presumably creating new associative links. We hypothesized that the putatively facilitated access should be reflected in increased activation of the amygdala upon bilateral EMDR stimulation even in healthy subjects. Methods We investigated 22 healthy female university students (mean 23.5 years) with fMRI. Subjects were scanned while confronted with blocks of disgusting and neutral picture stimuli. One third of the blocks was presented without any additional stimulation, one third with bilateral simultaneous auditory stimulation, and one third with bilateral alternating auditory stimulation as used in EMDR. Results Contrasting disgusting vs. neutral picture stimuli confirmed the expected robust effect of amygdala activation for all auditory stimulation conditions. The interaction analysis with the type of auditory stimulation revealed a specific increase in activation of the right amygdala for the bilateral alternating auditory stimulation. Activation of the left dorsolateral prefrontal cortex showed the opposite effect with decreased activation. Conclusions We demonstrate first time evidence for a putative neurobiological basis of the bilateral alternating stimulation as used in the EMDR method. The increase in limbic processing along with decreased frontal activation is in line with theoretical models of how bilateral alternating stimulation could help with therapeutic reintegration of information, and present findings may pave the way for future research on EMDR in the context of posttraumatic stress disorder. PMID:25165974

Do changes in spinal reflex excitability elicited by transcranial magnetic stimulation differ based on the site of cerebellar stimulation?

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Matsugi, Akiyoshi

2018-05-06

The present study aimed to investigate whether spinal reflex excitability is influenced by the site of cerebellar transcranial magnetic stimulation (C-TMS). Fourteen healthy volunteers (mean age: 24.6 ± 6.6 years [11 men]) participated. Participants lay on a bed in the prone position, with both ankle joints fixed to prevent unwanted movement. Right tibial nerve stimulation was provided to elicit the H-reflex in the right soleus muscle. Conditioning transcranial magnetic stimulation (TMS) was delivered at one of the following sites 110 ms prior to tibial stimulation: right, central, or left cerebellum; midline parietal (Pz) region; or sham stimulation. A total of 10 test trials were included for each condition, in random order. The unconditioned and conditioned H-reflexes were measured during random inter-test trials, and the cerebellar spinal facilitation (CSpF) ratios for each site were calculated (the ratio of conditioned to unconditioned H-reflexes). CSpF ratios were compared among TMS sites. CSpF ratios were significantly higher at cerebellar sites than at the Pz site or during sham stimulation. However, there was no significant difference in CSpF ratio among cerebellar sites. TMS conditioning over any part of the cerebellum facilitated the excitability of the spinal motoneuron pool. Facilitation of the H-reflex due to C-TMS may involve the effects of the bilateral descending tract of the spinal cord on the spinal motoneuron pool. Alternatively, direct brainstem stimulation may have activated portions of the bilateral descending tract of the spinal cord.

Combined motor point associative stimulation (MPAS) and transcranial direct current stimulation (tDCS) improves plateaued manual dexterity performance.

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Hoseini, Najmeh; Munoz-Rubke, Felipe; Wan, Hsuan-Yu; Block, Hannah J

2016-10-28

Motor point associative stimulation (MPAS) in hand muscles is known to modify motor cortex excitability and improve learning rate, but not plateau of performance, in manual dexterity tasks. Central stimulation of motor cortex, such as transcranial direct current stimulation (tDCS), can have similar effects if accompanied by motor practice, which can be difficult and tiring for patients. Here we asked whether adding tDCS to MPAS could improve manual dexterity in healthy individuals who are already performing at their plateau, with no motor practice during stimulation. We hypothesized that MPAS could provide enough coordinated muscle activity to make motor practice unnecessary, and that this combination of stimulation techniques could yield improvements even in subjects at or near their peak. If so, this approach could have a substantial effect on patients with impaired dexterity, who are far from their peak. MPAS was applied for 30min to two right hand muscles important for manual dexterity. tDCS was simultaneously applied over left sensorimotor cortex. The motor cortex input/output (I/O) curve was assessed with transcranial magnetic stimulation (TMS), and manual dexterity was assessed with the Purdue Pegboard Test. Compared to sham or cathodal tDCS combined with MPAS, anodal tDCS combined with MPAS significantly increased the plateau of manual dexterity. This result suggests that MPAS has the potential to substitute for motor practice in mediating a beneficial effect of tDCS on manual dexterity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Considering the influence of stimulation parameters on the effect of conventional and high-definition transcranial direct current stimulation.

Science.gov (United States)

To, Wing Ting; Hart, John; De Ridder, Dirk; Vanneste, Sven

2016-01-01

Recently, techniques to non-invasively modulate specific brain areas gained popularity in the form of transcranial direct current stimulation (tDCS) and high-definition transcranial direct current stimulation. These non-invasive techniques have already shown promising outcomes in various studies with healthy subjects as well as patient populations. Despite widespread dissemination of tDCS, there remain significant unknowns about the influence of a diverse number of tDCS parameters (e.g. polarity, size, position of electrodes & duration of stimulation) in inducing neurophysiological and behavioral effects. This article explores both techniques starting with the history of tDCS, to the differences between conventional tDCS and high-definition transcranial direct current stimulation, the underlying physiological mechanism, the (in)direct effects, the applications of tDCS with varying parameters, the efficacy, the safety issues and the opportunities for future research.

Electrical stimulation of the midbrain excites the auditory cortex asymmetrically.

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Quass, Gunnar Lennart; Kurt, Simone; Hildebrandt, Jannis; Kral, Andrej

2018-05-17

Auditory midbrain implant users cannot achieve open speech perception and have limited frequency resolution. It remains unclear whether the spread of excitation contributes to this issue and how much it can be compensated by current-focusing, which is an effective approach in cochlear implants. The present study examined the spread of excitation in the cortex elicited by electric midbrain stimulation. We further tested whether current-focusing via bipolar and tripolar stimulation is effective with electric midbrain stimulation and whether these modes hold any advantage over monopolar stimulation also in conditions when the stimulation electrodes are in direct contact with the target tissue. Using penetrating multielectrode arrays, we recorded cortical population responses to single pulse electric midbrain stimulation in 10 ketamine/xylazine anesthetized mice. We compared monopolar, bipolar, and tripolar stimulation configurations with regard to the spread of excitation and the characteristic frequency difference between the stimulation/recording electrodes. The cortical responses were distributed asymmetrically around the characteristic frequency of the stimulated midbrain region with a strong activation in regions tuned up to one octave higher. We found no significant differences between monopolar, bipolar, and tripolar stimulation in threshold, evoked firing rate, or dynamic range. The cortical responses to electric midbrain stimulation are biased towards higher tonotopic frequencies. Current-focusing is not effective in direct contact electrical stimulation. Electrode maps should account for the asymmetrical spread of excitation when fitting auditory midbrain implants by shifting the frequency-bands downward and stimulating as dorsally as possible. Copyright © 2018 Elsevier Inc. All rights reserved.

Enhanced motor skill acquisition in the non-dominant upper extremity using intermittent theta burst stimulation and transcranial direct current stimulation.

Science.gov (United States)

Butts, Raymond J; Kolar, Melissa B; Newman-Norlund, Roger D

2014-01-01

Individuals suffering from motor impairments often require physical therapy (PT) to help improve their level of function. Previous investigations suggest that both intermittent theta burst stimulation (iTBS) and bihemispheric transcranial direct current stimulation (tDCS) may increase the speed and extent of motor learning/relearning. The purpose of the current study was to explore the feasibility and effectiveness of a novel, non-invasive brain stimulation approach that combined an iTBS primer, and bihemispheric stimulation coupled with motor training. We hypothesized that individuals exposed to this novel treatment would make greater functional improvements than individuals undergoing sham stimulation when tested immediately following, 24-h, and 7-days post-training. A total of 26 right-handed, healthy young adults were randomly assigned to either a treatment (n = 15) or control group (n = 12). iTBS (20 trains of 10 pulse triplets each delivered at 80% active motor threshold (AMT) / 50 Hz over 191.84 s) and bihemispheric tDCS (1.0 ma for 20 min) were used as a primer to, and in conjunction with, 20 min of motor training, respectively. Our primary outcome measure was performance on the Jebsen-Taylor Hand Function (JTHF) test. Participants tolerated the combined iTBS/bihemispheric stimulation treatment without complaint. While performance gains in the sham and stimulation group were not significant immediately after training, they were nearly significant 24-h post training (p = 0.055), and were significant at 7-days post training (p iTBS/bihemispheric stimulation protocol is both feasible and effective. Future research should examine the mechanistic explanation of this approach as well as the potential of using this approach in clinical populations.

Infraclavicular brachial plexus block: Comparison of posterior cord stimulation with lateral or medial cord stimulation, a prospective double blinded study

Directory of Open Access Journals (Sweden)

Dushyant Sharma

2013-01-01

Full Text Available Background: Infraclavicular approach to the brachial plexus sheath provides anesthesia for surgery on the distal arm, elbow, forearm, wrist, and hand. It has been found that evoked distal motor response or radial nerve-type motor response has influenced the success rate of single-injection infraclavicular brachial plexus block. Aim: We conducted this study to compare the extent and effectiveness of infraclavicular brachial plexus block achieved by injecting a local anesthetic drug after finding specific muscle action due to neural stimulator guided posterior cord stimulation and lateral cord/medial cord stimulation. Methods: After ethical committee approval, patients were randomly assigned to one of the two study groups of 30 patients each. In group 1, posterior cord stimulation was used and in group 2 lateral/medial cord stimulation was used for infraclavicular brachial plexus block. The extent of motor block and effectiveness of sensory block were assessed. Results: All four motor nerves that were selected for the extent of block were blocked in 23 cases (76.7% in group 1 and in 15 cases (50.0% in group 2 (P:0.032. The two groups did not differ significantly in the number of cases in which 0, 1, 2, and 3 nerves were blocked (P>0.05. In group 1, significantly lesser number of patients had pain on surgical manipulation compared with patients of group 2 (P:0.037. Conclusion: Stimulating the posterior cord guided by a nerve stimulator before local anesthetic injection is associated with greater extent of block (in the number of motor nerves blocked and effectiveness of block (in reporting no pain during the surgery than stimulation of either the lateral or medial cord.

Transcutaneous Spinal Direct Current Stimulation (tsDCS

Directory of Open Access Journals (Sweden)

Filippo eCogiamanian

2012-07-01

Full Text Available In the past ten years renewed interest has centered on non-invasive transcutaneous weak direct currents applied over the scalp to modulate cortical excitability (brain polarization or transcranial direct current stimulation, tDCS. Extensive literature shows that tDCS induces marked changes in cortical excitability that outlast stimulation.Aiming at developing a new, non invasive, approach to spinal cord neuromodulation we assessed the after-effects of thoracic transcutaneous spinal DC stimulation (tsDCS on somatosensory potentials (SEPs evoked in healthy subjects by posterior tibial nerve (PTN stimulation. Our findings showed that thoracic anodal tsDCS depresses the cervico-medullary PTN-SEP component (P30 without eliciting adverse effects. tsDCS also modulates post-activation H-reflex dynamics. Later works further confirmed that transcutaneous electric fields modulate spinal cord function. Subsequent studies in our laboratory showed that tsDCS modulates the flexion reflex in the human lower limb. Besides influencing the laser evoked potentials, tsDCS increases pain tolerance in healthy subjects. Hence, though the underlying mechanisms remain speculative, tsDCS modulates activity in lemniscal, spinothalamic and segmental motor systems.Here we review currently available experimental evidence that non-invasive spinal cord stimulation influences spinal function in humans and argue that, by focally modulating spinal excitability, tsDCS could provide a novel therapeutic tool complementary to drugs and invasive spinal cord stimulation in managing various pathologic conditions, including pain.

Thermo-stimulated current and dielectric loss in composite materials

International Nuclear Information System (INIS)

Nishijima, S.; Hagihara, T.; Okada, T.

1986-01-01

Thermo-stimulated current and dielectric loss measurements have been performed on five kinds of commercially available composite materials in order to study the electric properties of composite materials at low temperatures. Thermo-stimulated current measurements have been made on the composite materials in which the matrix quality was changed intentionally. The changes in the matrices were introduced by gamma irradiation or different curing conditions. Thermo-stimulated current and dielectric loss measurements revealed the number and the molecular weight of dipolar molecules. The different features of thermo-stimulated current and dielectric losses were determined for different composite materials. The gamma irradiation and the curing conditions especially affect the thermo-stimulated current features. The changes in macroscopic mechanical properties reflect those of thermo-stimulated current. It was found that the change in quality and/or degradation of the composite materials could be detected by means of thermo-stimulated current and/or dielectric loss measurements

21 CFR 874.1800 - Air or water caloric stimulator.

Science.gov (United States)

2010-04-01

... vestibular function testing of a patient's body balance system. The vestibular stimulation of the... stimulator. (a) Identification. An air or water caloric stimulator is a device that delivers a stream of air...

Stimulation of protein synthesis by internalized insulin

International Nuclear Information System (INIS)

Miller, D.S.; Sykes, D.B.

1991-01-01

Previous studies showed that microinjected insulin stimulates transcription and translation in Stage 4 Xenopus oocytes by acting at nuclear and cytoplasmic sites. The present report is concerned with the question of whether hormone, internalized from an external medium, can act on those sites to alter cell function. Both intracellular accumulation of undegraded 125I-insulin and insulin-stimulated 35S-methionine incorporation into oocyte protein were measured. Anti-insulin antiserum and purified anti-insulin antibody were microinjected into the cytoplasm of insulin-exposed cells to determine if insulin derived from the medium acted through internal sites. In cells exposed for 2 h to 7 or 70 nM external insulin, methionine incorporation was stimulated, but intracellular hormone accumulation was minimal and microinjected antibody was without effect. In cells exposed for 24 h, methionine incorporation again increased, but now accumulation of undegraded, intracellular hormone was substantial (2.6 and 25.3 fmol with 7 and 70 nM, respectively), and microinjected anti-insulin antibody significantly reduced the insulin-stimulated component of incorporation; basal incorporation was not affected. For cells exposed to 70 nM insulin for 24 h, inhibition of the insulin-stimulated component was maximal at 39%. Thus under those conditions, about 40% of insulin's effects were mediated by the internal sites. Together, the data show that inhibition of insulin-stimulated protein synthesis by microinjected antibody was associated with the intracellular accumulation of insulin. They indicate that when oocytes are exposed to external insulin, hormone eventually gains access to intracellular sites of action and through these stimulates translation. Control of translation appears to be shared between the internal sites and the surface receptor

Analysis of Facial Expression by Taste Stimulation

Science.gov (United States)

Tobitani, Kensuke; Kato, Kunihito; Yamamoto, Kazuhiko

In this study, we focused on the basic taste stimulation for the analysis of real facial expressions. We considered that the expressions caused by taste stimulation were unaffected by individuality or emotion, that is, such expressions were involuntary. We analyzed the movement of facial muscles by taste stimulation and compared real expressions with artificial expressions. From the result, we identified an obvious difference between real and artificial expressions. Thus, our method would be a new approach for facial expression recognition.

THE AVAILABILITY AND PORTRAYAL OF STIMULANTS OVER THE INTERNET

Science.gov (United States)

Schepis, Ty S.; Marlowe, Douglas B.; Forman, Robert F.

2008-01-01

Purpose To quantify the online availability and portrayal of amphetamine-class prescription stimulants with a focus on those medications commonly prescribed to and abused by adolescents. Methods The Google™ search engine was used in searches to assess the frequency of websites offering to sell controlled stimulants (retail sites) or websites that directly linked to retail sites (portal sites). Also, separate searches evaluated the portrayal of controlled prescription stimulants by the initial 20 websites returned by Google™. Retail and portal website frequency was collected for each search. For searches measuring the portrayal of stimulants, webpages were categorized as pro-abuse, anti-abuse, neutral or other, based on set criteria. Results Sites offering to sell stimulants without a prescription were found for nearly all search terms. Across all searches, the Schedule III stimulants indicated for the treatment of obesity returned more sites offering to sell stimulants without a prescription than Schedule II stimulants indicated for the treatment of ADHD. Internet site portrayal of each stimulant varied. However, sites that contained “methamphetamine” often included anti-abuse information. Discussion The apparent availability of stimulants over the Internet without a prescription indicates the potential for a significant public health problem. The extent to which teens are obtaining these drugs via the Internet remains unclear, but clinicians must be aware of the potential for abuse, concomitant prescription use issues, illicit sources, and diversion of these highly addictive medications. Education of consumers and physicians as well as further governmental interventions is needed to limit the potential scope of this problem. PMID:18407040

The Effect of Electrical Stimulation in Improving Muscle Tone (Clinical)

Science.gov (United States)

Azman, M. F.; Azman, A. W.

2017-11-01

Electrical stimulation (ES) and also known as neuromuscular electrical stimulation (NMES) and transcutaneous electrical stimulation (TES) involves the use of electrical current to stimulate the nerves or nerve endings that innervate muscle beneath the skin. Electrical stimulation may be applied superficially on the skin (transcutaneously) or directly into a muscle or muscles (intramuscularly) for the primary purpose of enhancing muscle function. The basic theoretical premise is that if the peripheral nerve can be stimulated, the resulting excitation impulse will be transmitted along the nerve to the motor endplates in the muscle, producing a muscle contraction. In this work, the effect of mere electrical stimulation to the muscle bulk and strength are tested. This paper explains how electrical stimulation can affect the muscle bulk, muscle size, muscle tone, muscle atrophy and muscle strength. The experiment and data collection are performed on 5 subjects and the results obtained are analyzed. This research aims to understand the full potential of electrical stimulation and identifying its possible benefits or disadvantages to the muscle properties. The results indicated that electrical stimulation alone able to improve muscle properties but with certain limits and precautions which might be useful in rehabilitation programme.

New York Canyon Stimulation

Energy Technology Data Exchange (ETDEWEB)

Raemy, Bernard

2012-06-21

The New York Canyon Stimulation Project was to demonstrate the commercial application of Enhanced Geothermal System techniques in Buena Vista Valley area of Pershing County, Nevada. From October 2009 to early 2012, TGP Development Company aggressively implemented Phase I of Pre-Stimulation and Site/Wellbore readiness. This included: geological studies; water studies and analyses and procurement of initial permits for drilling. Oversubscription of water rights and lack of water needed for implementation of EGS were identified and remained primary obstacles. Despite extended efforts to find alternative solutions, the water supply circumstances could not be overcome and led TGP to determine a "No Go" decision and initiate project termination in April 2012.

Stimulation of Managers in Regional Enterprises

Directory of Open Access Journals (Sweden)

Vladimir Nikiforovich Belkin

2018-03-01

Full Text Available Most of the principles related to top managers work incentives were inherited from the planned economy that produces demotivation and opportunistic behaviour. Remuneration is a commercial secret and shall not be disclosed. The system of top managers’ stimulation is unbalanced and does not motivate them to achieve medium- and long-term goals of the company. The study pays great attention to the development of managers’ stimulation policies, the transparency of remuneration, correlation between pay and performance. We provide practical examples of foreign and national experience, showing the ability to ensure the transparency of remuneration of managers, and the relation between compensation and performance. These examples show that managers’ remuneration amount does not always correspond to the efficiency of enterprises and return on capital. To solve these problems, we offer to develop philosophy and policy for the stimulation of managers in enterprises. It will allow to find a balance between the interests of shareholders and managers. Furthermore, this philosophy will have a positive impact on the competitiveness of enterprises in a region. The policy of stimulating managers should include certain key areas. Firstly, it should ensure the competitiveness of managers’ remuneration. Secondly, it implies studying the motives of managers’ work and the integration of these motives in the development of incentive system for the managers. Thirdly, it should include an optimal combination of elements to stimulate labour: base salary, material and social remuneration, short and long-term remuneration, etc. And last, it should consider the indicators and norms of enterprise’s effectiveness as well as the assessment of working results of managers. The results of this research can be used for further study of the stimulation of managers’ work in Russian companies. They can also be used in practice for the analysis of labour incentives of

A Stimulator ASIC Featuring Versatile Management for Vestibular Prostheses.

Science.gov (United States)

Dai Jiang; Demosthenous, Andreas; Perkins, Timothy; Xiao Liu; Donaldson, Nick

2011-04-01

This paper presents a multichannel stimulator ASIC for an implantable vestibular prosthesis. The system features versatile stimulation management which allows fine setting of the parameters for biphasic stimulation pulses. To address the problem of charge imbalance due to rounding errors, the digital processor can calculate and provide accurate charge correction. A technique to reduce the data rate to the stimulator is described. The stimulator ASIC was implemented in 0.6-μ m high-voltage CMOS technology occupying an area of 2.27 mm(2). The measured performance of the ASIC has been verified using vestibular electrodes in saline.

Aromatase inhibitors in stimulated IVF cycles

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Tournaye Herman

2011-06-01

Full Text Available Abstract Aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with PCOS. Although several randomized trials have been conducted regarding their use as ovulation induction agents, only few trials are available regarding their efficacy in IVF stimulated cycles. Current available evidence support that letrozole may have a promising role in stimulated IVF cycles, either when administered during the follicular phase for ovarian stimulation. Especially for women with poor ovarian response, letrozole appears to have the potential to increase clinical pregnancy rates when combined with gonadotropins, whereas at the same time reduces the total gonadotropin dose required for ovarian stimulation. However, given that in all of the trials letrozole has been administered in GnRH antagonist cycles, it is intriguing to test in the future how it may perform when used in GnRH agonist cycles. Finally administration of letrozole during luteal phase in IVF cycles offers another treatment modality for patients at high risk for OHSS taking into account that it drastically reduces estradiol levels

Noninvasive brain stimulation with transcranial magnetic or direct current stimulation (TMS/tDCS)-From insights into human memory to therapy of its dysfunction.

Science.gov (United States)

Sparing, Roland; Mottaghy, Felix M

2008-04-01

Noninvasive stimulation of the brain by means of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) has driven important discoveries in the field of human memory functions. Stand-alone or in combination with other brain mapping techniques noninvasive brain stimulation can assess issues such as location and timing of brain activity, connectivity and plasticity of neural circuits and functional relevance of a circumscribed brain area to a given cognitive task. In this emerging field, major advances in technology have been made in a relatively short period. New stimulation protocols and, especially, the progress in the application of tDCS have made it possible to obtain longer and much clearer inhibitory or facilitatory effects even after the stimulation has ceased. In this introductory review, we outline the basic principles, discuss technical limitations and describe how noninvasive brain stimulation can be used to study human memory functions in vivo. Though improvement of cognitive functions through noninvasive brain stimulation is promising, it still remains an exciting challenge to extend the use of TMS and tDCS from research tools in neuroscience to the treatment of neurological and psychiatric patients.

Right-sided vagus nerve stimulation inhibits induced spinal cord seizures.

Science.gov (United States)

Tubbs, R Shane; Salter, E George; Killingsworth, Cheryl; Rollins, Dennis L; Smith, William M; Ideker, Raymond E; Wellons, John C; Blount, Jeffrey P; Oakes, W Jerry

2007-01-01

We have previously shown that left-sided vagus nerve stimulation results in cessation of induced spinal cord seizures. To test our hypothesis that right-sided vagus nerve stimulation will also abort seizure activity, we have initiated seizures in the spinal cord and then performed right-sided vagus nerve stimulation in an animal model. Four pigs were anesthetized and placed in the lateral position and a small laminectomy performed in the lumbar region. Topical penicillin, a known epileptogenic drug to the cerebral cortex and spinal cord, was next applied to the dorsal surface of the exposed cord. With the exception of the control animal, once seizure activity was discernible via motor convulsion or increased electrical activity, the right vagus nerve previously isolated in the neck was stimulated. Following multiple stimulations of the vagus nerve and with seizure activity confirmed, the cord was transected in the midthoracic region and vagus nerve stimulation performed. Right-sided vagus nerve stimulation resulted in cessation of spinal cord seizure activity in all animals. Transection of the spinal cord superior to the site of seizure induction resulted in the ineffectiveness of vagus nerve stimulation in causing cessation of seizure activity in all study animals. As with left-sided vagus nerve stimulation, right-sided vagus nerve stimulation results in cessation of induced spinal cord seizures. Additionally, the effects of right-sided vagus nerve stimulation on induced spinal cord seizures involve descending spinal pathways. These data may aid in the development of alternative mechanisms for electrical stimulation for patients with medically intractable seizures and add to our knowledge regarding the mechanism for seizure cessation following peripheral nerve stimulation.

Spinal cord stimulation for neuropathic pain: current perspectives.

Science.gov (United States)

Wolter, Tilman

2014-01-01

Neuropathic pain constitutes a significant portion of chronic pain. Patients with neuropathic pain are usually more heavily burdened than patients with nociceptive pain. They suffer more often from insomnia, anxiety, and depression. Moreover, analgesic medication often has an insufficient effect on neuropathic pain. Spinal cord stimulation constitutes a therapy alternative that, to date, remains underused. In the last 10 to 15 years, it has undergone constant technical advancement. This review gives an overview of the present practice of spinal cord stimulation for chronic neuropathic pain and current developments such as high-frequency stimulation and peripheral nerve field stimulation.

Improved Pain Relief With Burst Spinal Cord Stimulation for Two Weeks in Patients Using Tonic Stimulation: Results From a Small Clinical Study.

Science.gov (United States)

Courtney, Peter; Espinet, Anthony; Mitchell, Bruce; Russo, Marc; Muir, Andrew; Verrills, Paul; Davis, Kristina

2015-07-01

Conventional spinal cord stimulation (SCS) delivers a tonic waveform with consistent stream of pulses; burst delivers groups of pulses separated by short pulse-free periods. The current study compared the short-term safety and efficacy of burst with tonic stimulation in subjects already receiving SCS. At 4 IRB-approved sites, 22 subjects previously implanted with an SCS device for intractable, chronic pain gave informed consent and received burst stimulation for 14 days. Subjects reported average daily Visual Analog Scale (VAS) for overall, trunk, and limb pain using tonic stimulation and after 7 and 14 days of burst stimulation. Thoughts about pain were assessed using the Pain Catastrophizing Scale. Areas of paresthesia were assessed during tonic and burst stimulation using body maps. Assessment of patient satisfaction and preferred stimulation occurred after 14 days of burst. Average daily overall VAS reduced 46% from a mean of 53.5 (±20.2) mm during tonic SCS to 28.5 (±18.1) mm during burst (p pain relief was the most common reason cited for preference. A majority of subjects reported improved pain relief using burst compared with tonic stimulation. Most subjects experienced less paresthesia during burst and preferred burst citing better pain relief. © 2015 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.

Massive hydraulic fracturing gas stimulation project

International Nuclear Information System (INIS)

Appledorn, C.R.; Mann, R.L.

1977-01-01

The Rio Blanco Massive Hydraulic Fracturing Project was fielded in 1974 as a joint Industry/ERDA demonstration to test the relative formations that were stimulated by the Rio Blanco Nuclear fracturing experiment. The project is a companion effort to and a continuation of the preceding nuclear stimulation project, which took place in May 1973. 8 figures

Elevated progesterone during ovarian stimulation for IVF

DEFF Research Database (Denmark)

Al-Azemi, M; Kyrou, D; Kolibianakis, E M

2012-01-01

of Medline and PubMed were searched to identify relevant publications. Good-quality evidence supports the negative impact on endometrial receptivity of elevated progesterone concentrations at the end of the follicular phase in ovarian stimulation. Future trials should document the cause and origin...... phase in ovarian stimulation. The databases of Medline and PubMed were searched to identify relevant publications. Good-quality evidence supports the negative impact on endometrial receptivity of elevated progesterone concentrations at the end of follicular phase in ovarian stimulation. Future trials...

Enhanced Motor Skill Acquisition in the Non-dominant Upper Extremity using Intermittent Theta Burst Stimulation and Transcranial Direct Current Stimulation

Directory of Open Access Journals (Sweden)

Ray eButts

2014-06-01

Full Text Available Individuals suffering from motor impairments often require physical therapy (PT to help improve their level of function. Previous investigations suggest that both intermittent theta burst stimulation (iTBS and bihemispheric transcranial direct current stimulation may increase the speed and extent of motor learning/relearning and that this increase may be related to brain derived neurotrophic factor (BDNF. The purpose of the current study was to explore the feasibility and effectiveness of a novel, non-invasive brain stimulation approach that combined an iTBS primer, and bihemispheric stimulation coupled with motor training. We hypothesized that individuals exposed to this novel treatment would make greater functional improvements than individuals undergoing sham stimulation when tested immediately following, 24-hours, and 7-days post-training. A total of 26 right-handed, healthy young adults were randomly assigned to either a treatment (n = 15 or control group (n = 12. iTBS (20 trains of 10 pulse triplets each delivered at 80% AMT / 50Hz over 191.84 seconds and bihemispheric tDCS (1.0 ma for 20 minutes were used as a primer to, and in conjunction with, 20 minutes of motor training, respectively. Our primary outcome measure was performance on the Jebsen-Taylor Hand Function Test. Participants tolerated the combined iTBS/bihemispheric stimulation treatment without complaint. While performance gains in the sham and stimulation group were not significant immediately after training, they were nearly significant 24-hours post training (p = 0.055, and were significant at 7-days post training (p < 0.05. These results suggest that the combined iTBS/bihemispheric stimulation protocol is both feasible and effective. Future research should examine the mechanistic explanation of this approach as well as the potential of using this approach in clinical populations.

Sacral nerve stimulation increases activation of the primary somatosensory cortex by anal canal stimulation in an experimental model.

LENUS (Irish Health Repository)

Griffin, K M

2011-08-01

Sacral and posterior tibial nerve stimulation may be used to treat faecal incontinence; however, the mechanism of action is unknown. The aim of this study was to establish whether sensory activation of the cerebral cortex by anal canal stimulation was increased by peripheral neuromodulation.

Technological Advances in Deep Brain Stimulation.

Science.gov (United States)

Ughratdar, Ismail; Samuel, Michael; Ashkan, Keyoumars

2015-01-01

Functional and stereotactic neurosurgery has always been regarded as a subspecialty based on and driven by technological advances. However until recently, the fundamentals of deep brain stimulation (DBS) hardware and software design had largely remained stagnant since its inception almost three decades ago. Recent improved understanding of disease processes in movement disorders as well clinician and patient demands has resulted in new avenues of development for DBS technology. This review describes new advances both related to hardware and software for neuromodulation. New electrode designs with segmented contacts now enable sophisticated shaping and sculpting of the field of stimulation, potentially allowing multi-target stimulation and avoidance of side effects. To avoid lengthy programming sessions utilising multiple lead contacts, new user-friendly software allows for computational modelling and individualised directed programming. Therapy delivery is being improved with the next generation of smaller profile, longer-lasting, re-chargeable implantable pulse generators (IPGs). These include IPGs capable of delivering constant current stimulation or personalised closed-loop adaptive stimulation. Post-implantation Magnetic Resonance Imaging (MRI) has long been an issue which has been partially overcome with 'MRI conditional devices' and has enabled verification of DBS lead location. Surgical technique is considering a shift from frame-based to frameless stereotaxy or greater role for robot assisted implantation. The challenge for these contemporary techniques however, will be in demonstrating equivalent safety and accuracy to conventional methods. We also discuss potential future direction utilising wireless technology allowing for miniaturisation of hardware.

Modulating the brain at work using noninvasive transcranial stimulation.

Science.gov (United States)

McKinley, R Andy; Bridges, Nathaniel; Walters, Craig M; Nelson, Jeremy

2012-01-02

This paper proposes a shift in the way researchers currently view and use transcranial brain stimulation technologies. From a neuroscience perspective, the standard application of both transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) has been mainly to explore the function of various brain regions. These tools allow for noninvasive and painless modulation of cortical tissue. In the course of studying the function of an area, many studies often report enhanced performance of a task during or following the stimulation. However, little follow-up research is typically done to further explore these effects. Approaching this growing pool of cognitive neuroscience literature with a neuroergonomics mindset (i.e., studying the brain at work), the possibilities of using these stimulation techniques for more than simply investigating the function of cortical areas become evident. In this paper, we discuss how cognitive neuroscience brain stimulation studies may complement neuroergonomics research on human performance optimization. And, through this discussion, we hope to shift the mindset of viewing transcranial stimulation techniques as solely investigatory basic science tools or possible clinical therapeutic devices to viewing transcranial stimulation techniques as interventional tools to be incorporated in applied science research and systems for the augmentation and enhancement of human operator performance. Published by Elsevier Inc.

Neural dynamics during repetitive visual stimulation

Science.gov (United States)

Tsoneva, Tsvetomira; Garcia-Molina, Gary; Desain, Peter

2015-12-01

Objective. Steady-state visual evoked potentials (SSVEPs), the brain responses to repetitive visual stimulation (RVS), are widely utilized in neuroscience. Their high signal-to-noise ratio and ability to entrain oscillatory brain activity are beneficial for their applications in brain-computer interfaces, investigation of neural processes underlying brain rhythmic activity (steady-state topography) and probing the causal role of brain rhythms in cognition and emotion. This paper aims at analyzing the space and time EEG dynamics in response to RVS at the frequency of stimulation and ongoing rhythms in the delta, theta, alpha, beta, and gamma bands. Approach.We used electroencephalography (EEG) to study the oscillatory brain dynamics during RVS at 10 frequencies in the gamma band (40-60 Hz). We collected an extensive EEG data set from 32 participants and analyzed the RVS evoked and induced responses in the time-frequency domain. Main results. Stable SSVEP over parieto-occipital sites was observed at each of the fundamental frequencies and their harmonics and sub-harmonics. Both the strength and the spatial propagation of the SSVEP response seem sensitive to stimulus frequency. The SSVEP was more localized around the parieto-occipital sites for higher frequencies (>54 Hz) and spread to fronto-central locations for lower frequencies. We observed a strong negative correlation between stimulation frequency and relative power change at that frequency, the first harmonic and the sub-harmonic components over occipital sites. Interestingly, over parietal sites for sub-harmonics a positive correlation of relative power change and stimulation frequency was found. A number of distinct patterns in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (15-30 Hz) bands were also observed. The transient response, from 0 to about 300 ms after stimulation onset, was accompanied by increase in delta and theta power over fronto-central and occipital sites, which returned to baseline

Electrical and optical co-stimulation in the deaf white cat

Science.gov (United States)

Cao, Zhiping; Xu, Yingyue; Tan, Xiaodong; Suematsu, Naofumi; Robinson, Alan; Richter, Claus-Peter

2018-02-01

Spatial selectivity of neural stimulation with photons, such as infrared neural stimulation (INS) is higher than the selectivity obtained with electrical stimulation. To obtain more independent channels for stimulation in neural prostheses, INS may be implemented to better restore the fidelity of the damaged neural system. However, irradiation with infrared light also bares the risk of heat accumulation in the target tissue with subsequent neural damage. Lowering the threshold for stimulation could reduce the amount of heat delivered to the tissue and the risk for subsequent tissue damage. It has been shown in the rat sciatic nerve that simultaneous irradiation with infrared light and the delivery of biphasic sub-threshold electrical pulses can reduce the threshold for INS [1]. In this study, deaf white cats have been used to test whether opto-electrical co-stimulation can reduce the stimulation threshold for INS in the auditory system too. The cochleae of the deaf white cats have largely reduced spiral ganglion neuron counts and significant degeneration of the organ of Corti and do not respond to acoustic stimuli. Combined electrical and optical stimulation was used to demonstrate that simultaneous stimulation with infrared light and biphasic electrical pulses can reduce the threshold for stimulation.

Anal sphincter responses after perianal electrical stimulation

DEFF Research Database (Denmark)

Pedersen, Ejnar; Klemar, B; Schrøder, H D

1982-01-01

By perianal electrical stimulation and EMG recording from the external anal sphincter three responses were found with latencies of 2-8, 13-18 and 30-60 ms, respectively. The two first responses were recorded in most cases. They were characterised by constant latency and uniform pattern, were...... not fatigued by repeated stimulation, were most dependent on placement of stimulating and recording electrodes, and always had a higher threshold than the third response. The third response was constantly present in normal subjects. It had the longest EMG response and the latency decreased with increasing...... stimulation to a minimum of 30-60 ms. This response represented the clinical observable spinal reflex, "the classical anal reflex". The latencies of the two first responses were so short that they probably do not represent spinal reflexes. This was further supported by the effect of epidural anaesthesia which...

Thermally stimulated exoelectron emission from solid Xe

International Nuclear Information System (INIS)

Khyzhniy, I.V.; Grigorashchenko, O.N.; Savchenko, E.V.; Ponomarev, A.N.; Bondybey, V.E.

2007-01-01

Thermally-stimulated emission of exoelectrons and photons from solid Xe pre-irradiated by low-energy electrons were studied. A high sensitivity of thermally-stimulated luminescence (TSL) and thermally-stimulated exoelectron emission (TSEE) to sample prehistory was demonstrated. It was shown that electron traps in unannealed samples are characterized by much broader distribution of trap levels in comparison with annealed samples and their concentration exceeds in number that in annealed samples. Both phenomena, TSL and TSEE, were found to be triggered by release of electrons from the same kind of traps. The data obtained suggest a competition between two relaxation channels: charge recombination and electron transport terminated by TSL and TSEE. It was found that TSEE predominates at low temperatures while at higher temperatures TSL prevails. An additional relaxation channel, a photon-stimulated exoelectron emission pre-irradiated solid Xe, was revealed

Effect of electrical stimulation on consumer acceptance of mutton ...

African Journals Online (AJOL)

MarianaD

-voltage electrical stimulation, HVES – high-voltage electrical stimulation, ... Electrical stimulation varied between 21 V – 1100 V. The drop in pH was significantly faster in the .... Table 2 Gender and age distribution of consumer panel (n=229).

Optimal stimulation as theoretical basis of hyperactivity.

Science.gov (United States)

Zentall, Sydney

1975-07-01

Current theory and practice in the clinical and educational management of hyperactive children recommend reduction of environmental stimulation, assuming hyperactive and distractable behaviors to be due to overstimulation. This paper reviews research suggesting that hyperactive behavior may result from a homeostatic mechanism that functions to increase stimulation for a child experienceing insufficient sensory stimulation. It is suggested that the effectiveness of drug and behavior therapies, as well as evidence from the field of sensory deprivation, further support the theory of a homeostatic mechanism that attempts to optimize sensory input.

Cortical Plasticity Induction by Pairing Subthalamic Nucleus Deep-Brain Stimulation and Primary Motor Cortical Transcranial Magnetic Stimulation in Parkinson's Disease.

Science.gov (United States)

Udupa, Kaviraja; Bahl, Nina; Ni, Zhen; Gunraj, Carolyn; Mazzella, Filomena; Moro, Elena; Hodaie, Mojgan; Lozano, Andres M; Lang, Anthony E; Chen, Robert

2016-01-13

Noninvasive brain stimulation studies have shown abnormal motor cortical plasticity in Parkinson's disease (PD). These studies used peripheral nerve stimulation paired with transcranial magnetic stimulation (TMS) to primary motor cortex (M1) at specific intervals to induce plasticity. Induction of cortical plasticity through stimulation of the basal ganglia (BG)-M1 connections has not been studied. In the present study, we used a novel technique of plasticity induction by repeated pairing of deep-brain stimulation (DBS) of the BG with M1 stimulation using TMS. We hypothesize that repeated pairing of subthalamic nucleus (STN)-DBS and M1-TMS at specific time intervals will lead to plasticity in the M1. Ten PD human patients with STN-DBS were studied in the on-medication state with DBS set to 3 Hz. The interstimulus intervals (ISIs) between STN-DBS and TMS that produced cortical facilitation were determined individually for each patient. Three plasticity induction conditions with repeated pairings (180 times) at specific ISIs (∼ 3 and ∼ 23 ms) that produced cortical facilitation and a control ISI of 167 ms were tested in random order. Repeated pairing of STN-DBS and M1-TMS at short (∼ 3 ms) and medium (∼ 23 ms) latencies increased M1 excitability that lasted for at least 45 min, whereas the control condition (fixed ISI of 167 ms) had no effect. There were no specific changes in motor thresholds, intracortical circuits, or recruitment curves. Our results indicate that paired-associative cortical plasticity can be induced by repeated STN and M1 stimulation at specific intervals. These results show that STN-DBS can modulate cortical plasticity. We introduced a new experimental paradigm to test the hypothesis that pairing subthalamic nucleus deep-brain stimulation (STN-DBS) with motor cortical transcranial magnetic stimulation (M1-TMS) at specific times can induce cortical plasticity in patients with Parkinson's disease (PD). We found that repeated pairing of STN

Transcranial direct-current stimulation as treatment in epilepsy.

Science.gov (United States)

Gschwind, Markus; Seeck, Margitta

2016-12-01

Neuromodulation (NM) is a complementary therapy for patients with drug-resistant epilepsy. Vagal nerve stimulation and deep brain stimulation of the anterior thalamus are established techniques and have shown their efficacy in lowering seizure frequency, but they are invasive and rarely render patients seizure-free. Non-invasive NM techniques are therefore increasingly investigated in a clinical context. Areas covered: Current knowledge about transcranial direct-current stimulation (tDCS) and other non-invasive NM in patients with epilepsy, based on the available animal and clinical studies from PubMed search. Expert commentary: tDCS modulates neuronal membrane potentials, and consequently alters cortical excitability. Cathodal stimulation leads to cortical inhibition, which is of particular importance in epilepsy treatment. The antiepileptic efficacy is promising but still lacks systematic studies. The beneficial effect, seen in ~20%, outlasts the duration of stimulation, indicating neuronal plasticity and is therefore of great interest to obtain long-term effects.

Precise positional measurement system in transcranial magnetic stimulation

International Nuclear Information System (INIS)

Inoue, Tomonori; Mishima, Yukuo; Hiwaki, Osamu

2006-01-01

Transcranial magnetic stimulation (TMS) is a method for noninvasive stimulation of cerebral cortex, and it has contributed to clinical and basic researches of brain function. In order to estimate the accurate stimulating points of the cortex in TMS, precise measurement of the subject's head and the stimulating coil is necessary. In this study, we have developed the positioning TMS system with a three-dimensional (3-D) digitizer and a multi-articular system. We proposed a method for the accurate measurement of a subject's head and cortex, in which the location data of the subject's face surface captured by a 3-D digitizer were superimposed on the magnetic resonance imaging (MRI) data of the subject's face surface. Using this system, the precise estimation of the stimulated sites of the cortex in TMS was achieved. The validity of the system was verified by the experiment on the TMS of the motor cortex. (author)

Effects of polycationic compounds on mitogen stimulation

DEFF Research Database (Denmark)

Heron, I; Larsen, B; Hokland, M

1981-01-01

The effects of polycations added to phytomitogen stimulated human lymphocyte cultures have been studied. Within certain dose ranges all polycations tested gave rise to augmented thymidine uptake in mitogen stimulated cultures. The optimum enhancing concentrations of polycations was depending on t...

Stimulation of seeds by low dose irradiation

International Nuclear Information System (INIS)

Lawson, Helen

1976-05-01

The first section of the bibliography lists materials on the stimulation of seeds by low dose irradiation, with particular reference to stimulation of germination and yield. The second section contains a small number of selected references on seed irradiation facilities. (author)

Boosting the LTP-like plasticity effect of intermittent theta-burst stimulation using gamma transcranial alternating current stimulation.

Science.gov (United States)

Guerra, Andrea; Suppa, Antonio; Bologna, Matteo; D'Onofrio, Valentina; Bianchini, Edoardo; Brown, Peter; Di Lazzaro, Vincenzo; Berardelli, Alfredo

2018-03-24

Transcranial Alternating Current Stimulation (tACS) consists in delivering electric current to the brain using an oscillatory pattern that may entrain the rhythmic activity of cortical neurons. When delivered at gamma frequency, tACS modulates motor performance and GABA-A-ergic interneuron activity. Since interneuronal discharges play a crucial role in brain plasticity phenomena, here we co-stimulated the primary motor cortex (M1) in healthy subjects by means of tACS during intermittent theta-burst stimulation (iTBS), a transcranial magnetic stimulation paradigm known to induce long-term potentiation (LTP)-like plasticity. We measured and compared motor evoked potentials before and after gamma, beta and sham tACS-iTBS. While we delivered gamma-tACS, we also measured short-interval intracortical inhibition (SICI) to detect any changes in GABA-A-ergic neurotransmission. Gamma, but not beta and sham tACS, significantly boosted and prolonged the iTBS-induced after-effects. Interestingly, the extent of the gamma tACS-iTBS after-effects correlated directly with SICI changes. Overall, our findings point to a link between gamma oscillations, interneuronal GABA-A-ergic activity and LTP-like plasticity in the human M1. Gamma tACS-iTBS co-stimulation might represent a new strategy to enhance and prolong responses to plasticity-inducing protocols, thereby lending itself to future applications in the neurorehabilitation setting. Copyright © 2018 Elsevier Inc. All rights reserved.

Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

Science.gov (United States)

Moloney, Tonya M; Witney, Alice G

2014-01-01

The primary motor cortex (M1) is an effective target of non-invasive cortical stimulation (NICS) for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. Here we investigate whether transcranial direct current stimulation (tDCS) primed 1 Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs) from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST) through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (ppain thresholds (ppain. This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

Electrical Stimulation for Pressure Injuries: A Health Technology Assessment.

Science.gov (United States)

2017-01-01

Pressure injuries (bedsores) are common and reduce quality of life. They are also costly and difficult to treat. This health technology assessment evaluates the effectiveness, cost-effectiveness, budget impact, and lived experience of adding electrical stimulation to standard wound care for pressure injuries. We conducted a systematic search for studies published to December 7, 2016, limited to randomized and non-randomized controlled trials examining the effectiveness of electrical stimulation plus standard wound care versus standard wound care alone for patients with pressure injuries. We assessed the quality of evidence through Grading of Recommendations Assessment, Development, and Evaluation (GRADE). In addition, we conducted an economic literature review and a budget impact analysis to assess the cost-effectiveness and affordability of electrical stimulation for treatment of pressure ulcers in Ontario. Given uncertainties in clinical evidence and resource use, we did not conduct a primary economic evaluation. Finally, we conducted qualitative interviews with patients and caregivers about their experiences with pressure injuries, currently available treatments, and (if applicable) electrical stimulation. Nine randomized controlled trials and two non-randomized controlled trials were found from the systematic search. There was no significant difference in complete pressure injury healing between adjunct electrical stimulation and standard wound care. There was a significant difference in wound surface area reduction favouring electrical stimulation compared with standard wound care.The only study on cost-effectiveness of electrical stimulation was partially applicable to the patient population of interest. Therefore, the cost-effectiveness of electrical stimulation cannot be determined. We estimate that the cost of publicly funding electrical stimulation for pressure injuries would be $0.77 to $3.85 million yearly for the next 5 years.Patients and caregivers

Electrical Stimulation for Pressure Injuries: A Health Technology Assessment

Science.gov (United States)

Lambrinos, Anna; Falk, Lindsey; Ali, Arshia; Holubowich, Corinne; Walter, Melissa

2017-01-01

Background Pressure injuries (bedsores) are common and reduce quality of life. They are also costly and difficult to treat. This health technology assessment evaluates the effectiveness, cost-effectiveness, budget impact, and lived experience of adding electrical stimulation to standard wound care for pressure injuries. Methods We conducted a systematic search for studies published to December 7, 2016, limited to randomized and non–randomized controlled trials examining the effectiveness of electrical stimulation plus standard wound care versus standard wound care alone for patients with pressure injuries. We assessed the quality of evidence through Grading of Recommendations Assessment, Development, and Evaluation (GRADE). In addition, we conducted an economic literature review and a budget impact analysis to assess the cost-effectiveness and affordability of electrical stimulation for treatment of pressure ulcers in Ontario. Given uncertainties in clinical evidence and resource use, we did not conduct a primary economic evaluation. Finally, we conducted qualitative interviews with patients and caregivers about their experiences with pressure injuries, currently available treatments, and (if applicable) electrical stimulation. Results Nine randomized controlled trials and two non–randomized controlled trials were found from the systematic search. There was no significant difference in complete pressure injury healing between adjunct electrical stimulation and standard wound care. There was a significant difference in wound surface area reduction favouring electrical stimulation compared with standard wound care. The only study on cost-effectiveness of electrical stimulation was partially applicable to the patient population of interest. Therefore, the cost-effectiveness of electrical stimulation cannot be determined. We estimate that the cost of publicly funding electrical stimulation for pressure injuries would be $0.77 to $3.85 million yearly for the next 5

Criminality Among Rural Stimulant Users in the United States

OpenAIRE

Oser, Carrie; Leukefeld, Carl; Staton-Tindall, Michele; Duvall, Jamieson; Garrity, Thomas; Stoops, William; Falck, Russel; Wang, Jichuan; Carlson, Robert; Sexton, Rocky; Wright, Patricia; Booth, Brenda

2011-01-01

Despite the increase in media attention on “meth cooking” in rural areas of the United States, little is known about rural stimulant use, particularly the criminality associated with stimulant use. Data were collected from community stimulant users in rural Ohio, Arkansas, and Kentucky (N=709). Findings from three logistic regression models indicate that younger stimulant users (x =32.55, SD = 10.35), those with more convictions, and those who used crack frequently were significantly more lik...

A Radiation Dosimetry Method Using Pulsed Optically Stimulated Luminescence

International Nuclear Information System (INIS)

Akselrod, M.S.; McKeever, S.W.S.

1999-01-01

A method for the determination of absorbed radiation dose is described based on pulsed optically stimulated luminescence (POSL). The method relies upon the stimulation of an irradiated sample with a train of light pulses from a suitable light source (e.g. a laser) using a wavelength which is within the range of wavelengths corresponding to the radiation-induced optical absorption in the irradiated sample. The subsequent emitted light, due to the detrapping of trapped charges and their subsequent recombination with charge of the opposite sign, is synchronously detected in the period between each stimulation pulse. The total luminescence is summed over the desired number of stimulation pulses and this forms the measured POSL signal. By monitoring the emitted light only in the period between stimulation pulses one can reduce the optical filtering required to discriminate between the stimulation light and the emission light; in this way a high measurement efficiency, and, therefore, a high radiation sensitivity (luminescence intensity per unit absorbed dose) is achieved. Key parameters in the method are the intrinsic luminescence lifetime for the material being used as the luminescent detector, the width of the optical stimulation pulse, and the period between pulses. For optimum operation the measurement parameters should be such that both the pulse width and the time between pulses are much less than the luminescence lifetime. By appropriate choice of the power of the optical stimulation, the frequency of the stimulation pulses, and the total stimulation period, one can also re-measure the absorbed dose several times. In this way, a re-read capability is available with the procedure. The method is illustrated using light from a 2nd-harmonic Nd:YAG laser, with irradiated, anion-deficient aluminium oxide as the luminescent detector material. (author)

Thyroid stimulating hormone and subclinical thyroid dysfunction

International Nuclear Information System (INIS)

Guo Yongtie

2008-01-01

Subclinical thyroid dysfunction has mild clinical symptoms. It is nonspecific and not so noticeable. It performs only for thyroid stimulating hormone rise and decline. The value of early diagnosis and treatment of thyroid stimulating hormone in subclinical thyroid dysfunction were reviewed. (authors)

Closed loop deep brain stimulation: an evolving technology.

Science.gov (United States)

Hosain, Md Kamal; Kouzani, Abbas; Tye, Susannah

2014-12-01

Deep brain stimulation is an effective and safe medical treatment for a variety of neurological and psychiatric disorders including Parkinson's disease, essential tremor, dystonia, and treatment resistant obsessive compulsive disorder. A closed loop deep brain stimulation (CLDBS) system automatically adjusts stimulation parameters by the brain response in real time. The CLDBS continues to evolve due to the advancement in the brain stimulation technologies. This paper provides a study on the existing systems developed for CLDBS. It highlights the issues associated with CLDBS systems including feedback signal recording and processing, stimulation parameters setting, control algorithm, wireless telemetry, size, and power consumption. The benefits and limitations of the existing CLDBS systems are also presented. Whilst robust clinical proof of the benefits of the technology remains to be achieved, it has the potential to offer several advantages over open loop DBS. The CLDBS can improve efficiency and efficacy of therapy, eliminate lengthy start-up period for programming and adjustment, provide a personalized treatment, and make parameters setting automatic and adaptive.

Optogenetic stimulation effectively enhances intrinsically generated network synchrony

Science.gov (United States)

El Hady, Ahmed; Afshar, Ghazaleh; Bröking, Kai; Schlüter, Oliver M.; Geisel, Theo; Stühmer, Walter; Wolf, Fred

2013-01-01

Synchronized bursting is found in many brain areas and has also been implicated in the pathophysiology of neuropsychiatric disorders such as epilepsy, Parkinson’s disease, and schizophrenia. Despite extensive studies of network burst synchronization, it is insufficiently understood how this type of network wide synchronization can be strengthened, reduced, or even abolished. We combined electrical recording using multi-electrode array with optical stimulation of cultured channelrhodopsin-2 transducted hippocampal neurons to study and manipulate network burst synchronization. We found low frequency photo-stimulation protocols that are sufficient to induce potentiation of network bursting, modifying bursting dynamics, and increasing interneuronal synchronization. Surprisingly, slowly fading-in light stimulation, which substantially delayed and reduced light-driven spiking, was at least as effective in reorganizing network dynamics as much stronger pulsed light stimulation. Our study shows that mild stimulation protocols that do not enforce particular activity patterns onto the network can be highly effective inducers of network-level plasticity. PMID:24155695

Optogenetic stimulation effectively enhances intrinsically generated network synchrony

Directory of Open Access Journals (Sweden)

Ahmed eEl Hady

2013-10-01

Full Text Available Synchronized bursting is found in many brain areas and has also been implicated in the pathophysiology of neuropsychiatric disorders such as epilepsy, Parkinson’s disease and schizophrenia. Despite extensive studies of network burst synchronization, it is insufficiently understood how this type of network wide synchronization can be strengthened, reduced or even abolished. We combined electrical recording using multi-electrode array with optical stimulation of cultured channelrhodopsin-2 transducted hippocampal neurons to study and manipulate network burst synchronization. We found low frequency photo-stimulation protocols that are sufficient to induce potentiation of network bursting, modifying bursting dynamics and increasing interneuronal synchronization. Surprisingly, slowly fading-in light stimulation, which substantially delayed and reduced light driven spiking, was at least as effective in reorganizing network dynamics as much stronger pulsed light stimulation. Our study shows that mild stimulation protocols that do not enforce particular activity patterns onto the network can be highly effective inducers of network-level plasticity.

Are Prescription Stimulants "Smart Pills"? The Epidemiology and Cognitive Neuroscience of Prescription Stimulant Use by Normal Healthy Individuals

Science.gov (United States)

Smith, M. Elizabeth; Farah, Martha J.

2011-01-01

Use of prescription stimulants by normal healthy individuals to enhance cognition is said to be on the rise. Who is using these medications for cognitive enhancement, and how prevalent is this practice? Do prescription stimulants in fact enhance cognition for normal healthy people? We review the epidemiological and cognitive neuroscience…

NTP-CERHR monograph on Soy Infant Formula.

Science.gov (United States)

2010-09-01

Soy infant formula contains soy protein isolates and is fed to infants as a supplement to or replacement for human milk or cow milk. Soy protein isolates contains estrogenic isoflavones ("phytoestrogens") that occur naturally in some legumes, especially soybeans. Phytoestrogens are non-steroidal, estrogenic compounds. In plants, nearly all phytoestrogens are bound to sugar molecules and these phytoestrogen-sugar complexes are not generally considered hormonally active. Phytoestrogens are found in many food products in addition to soy infant formula, especially soy-based foods such as tofu, soy milk, and in some over-the-counter dietary supplements. Soy infant formula was selected for evaluation by the National Toxicology Program (NTP) because of the: (1)availability of large number of developmental toxicity studies in laboratory animals exposed to the isoflavones found in soy infant formula (namely, genistein) or other soy products, as well as a number of studies on human infants fed soy infant formula, (2)the availability of information on exposures in infants fed soy infant formula, and (3)public concern for effects on infant or child development. The NTP evaluation was conducted through its Center for the Evaluation of Risks to Human Reproduction (CERHR) and completed in September 2010. The results of this soy infant formula evaluation are published in an NTP Monograph. This document contains the NTP Brief on Soy Infant Formula, which presents NTP's opinion on the potential for exposure to soy infant formula to cause adverse developmental effects in humans. The NTP Monograph also contains an expert panel report prepared to assist the NTP in reaching conclusions on soy infant formula. The NTP concluded there is minimal concern for adverse effects on development in infants who consume soy infant formula. This level of concern represents a "2" on the five-level scale of concern used by the NTP that ranges from negligible concern ("1") to serious concern ("5"). This

The inability of phosphatidylinositol 3-kinase activation to stimulate GLUT4 translocation indicates additional signaling pathways are required for insulin-stimulated glucose uptake.

Science.gov (United States)

Isakoff, S J; Taha, C; Rose, E; Marcusohn, J; Klip, A; Skolnik, E Y

1995-10-24

Recent experimental evidence has focused attention to the role of two molecules, insulin receptor substrate 1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase), in linking the insulin receptor to glucose uptake; IRS-1 knockout mice are insulin resistant, and pharmacological inhibitors of PI3-kinase block insulin-stimulated glucose uptake. To investigate the role of PI3-kinase and IRS-1 in insulin-stimulated glucose uptake we examined whether stimulation of insulin-sensitive cells with platelet-derived growth factor (PDGF) or with interleukin 4 (IL-4) stimulates glucose uptake; the activated PDGF receptor (PDGFR) directly binds and activates PI3-kinase, whereas the IL-4 receptor (IL-4R) activates PI3-kinase via IRS-1 or the IRS-1-related molecule 4PS. We found that stimulation of 3T3-L1 adipocytes with PDGF resulted in tyrosine phosphorylation of the PDGFR and activation of PI3-kinase in these cells. To examine whether IL-4 stimulates glucose uptake, L6 myoblasts were engineered to overexpress GLUT4 as well as both chains of the IL-4R (L6/IL-4R/GLUT4); when these L6/IL-4R/GLUT4 myoblasts were stimulated with IL-4, IRS-1 became tyrosine phosphorylated and associated with PI3-kinase. Although PDGF and IL-4 can activate PI3-kinase in the respective cell lines, they do not possess insulin's ability to stimulate glucose uptake and GLUT4 translocation to the plasma membrane. These findings indicate that activation of PI3-kinase is not sufficient to stimulate GLUT4 translocation to the plasma membrane. We postulate that activation of a second signaling pathway by insulin, distinct from PI3-kinase, is necessary for the stimulation of glucose uptake in insulin-sensitive cells.

Motor cortex stimulation: role of computer modeling

NARCIS (Netherlands)

Manola, L.; Holsheimer, J.; Sakas, D.E.; Simpson, B.A

Motor cortex stimulation (MCS) is a promising clinical technique used to treat chronic, otherwise intractable pain. However, the mechanisms by which the neural elements that are stimulated during MCS induce pain relief are not understood. Neither is it known which neural elements (fibers (parallel

Kinetics of infrared stimulated luminescence from feldspars

DEFF Research Database (Denmark)

Jain, Mayank; Sohbati, Reza; Guralnik, Benny

2015-01-01

thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

[Relationship between phthalates and testicular dysgenesis syndrome].

Science.gov (United States)

Chen, Guo-Rong; Dong, Lei; Ge, Ren-Shan; Hardy, Matthew P

2007-03-01

Recent epidemiological evidence demonstrates that boys born to women exposed to phthalates during pregnancy have an increased incidence of cryptorchidism, hypospadias, testicular cancer and spermatogenic dysfunction, which are collectively referred to as testicular dysgenesis syndrome (TDS). TDS may be attributed to the dysfunction of Leydig cells and Sertoli cells during their differentiation after exposure to phthalates in utero. Fox example, Leydig cell functions are significantly affected by phthalates, leading to the decrease of two Leydig cell products--insulin-like growth factor 3 (INSL3) and testosterone, which are critical factors for testis descent. The disorientation of Leydig cells and Sertoli cells in the adult testis may be the cause of spermatogenic dysfunction.

Synergistic nonuniform shortening of atrial refractory period induced by autonomic stimulation.

Science.gov (United States)

Takei, M; Furukawa, Y; Narita, M; Ren, L M; Karasawa, Y; Murakami, M; Chiba, S

1991-12-01

We investigated the nonuniform effects of autonomic nerve stimulation of the effective refractory period (ERP) of the right atrium in the anesthetized dog. Stimulation of the discrete intracardiac sympathetic nerves to the sinoatrial (SA) nodal region uniformly shortened ERPs at three sites in the right atrium after administration of atropine. Right ansa subclavia (RS) stimulation similarly shortened ERPs in the absence of atropine. Stimulation of the discrete intracardiac parasympathetic nerves to the SA nodal region (SAP stimulation) shortened ERPs of the right atrium in a nonuniform manner. Simultaneous RS and SAP stimulation additively shortened ERPs at each site and decreased sinus rate much more than SAP stimulation alone. Shortening of ERP induced by SAP stimulation was greater than that induced by RS stimulation at similar absolute changes in heart rate. These results suggest that simultaneous activation of sympathetic and parasympathetic nerves nonuniformly shortens the ERP in the right atrium as the algebraic sum of the individual responses to each stimulation. However, parasympathetics exert the principal neural control over atrial ERP.

Appetite stimulants for people with cystic fibrosis.

Science.gov (United States)

Chinuck, Ruth; Dewar, Jane; Baldwin, David R; Hendron, Elizabeth

2014-07-27

Chronic loss of appetite in cystic fibrosis concerns both individuals and families. Appetite stimulants have been used to help cystic fibrosis patients with chronic anorexia attain optimal body mass index and nutritional status. However, these may have adverse effects on clinical status. The aim of this review is to systematically search for and evaluate evidence on the beneficial effects of appetite stimulants in the management of CF-related anorexia and synthesize reports of any side-effects. Trials were identified by searching the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register, MEDLINE, Embase, CINAHL, handsearching reference lists and contacting local and international experts.Last search of online databases: 01 April 2014.Last search of the Cystic Fibrosis Trials Register: 08 April 2014. Randomised and quasi-randomised controlled trials of appetite stimulants, compared to placebo or no treatment for at least one month in adults and children with cystic fibrosis. Authors independently extracted data and assessed the risk of bias within eligible trials. Meta-analyses were performed. Three trials (total of 47 recruited patients) comparing appetite stimulants (cyproheptadine hydrochloride and megesterol acetate) to placebo were included; the numbers of adults or children within each trial were not always reported. The risk of bias of the included trials was graded as moderate.A meta-analysis of all three trials showed appetite stimulants produced a larger increase in weight z score at three months compared to placebo, mean difference 0.61 (95% confidence interval 0.29 to 0.93) (P children, appetite stimulants improved only two of the outcomes in this review - weight (or weight z score) and appetite; and side effects were insufficiently reported to determine the full extent of their impact. Whilst the data may suggest the potential use of appetite stimulants in treating anorexia in adults and children with cystic fibrosis

Design of efficient and safe neural stimulators a multidisciplinary approach

CERN Document Server

van Dongen, Marijn

2016-01-01

This book discusses the design of neural stimulator systems which are used for the treatment of a wide variety of brain disorders such as Parkinson’s, depression and tinnitus. Whereas many existing books treating neural stimulation focus on one particular design aspect, such as the electrical design of the stimulator, this book uses a multidisciplinary approach: by combining the fields of neuroscience, electrophysiology and electrical engineering a thorough understanding of the complete neural stimulation chain is created (from the stimulation IC down to the neural cell). This multidisciplinary approach enables readers to gain new insights into stimulator design, while context is provided by presenting innovative design examples. Provides a single-source, multidisciplinary reference to the field of neural stimulation, bridging an important knowledge gap among the fields of bioelectricity, neuroscience, neuroengineering and microelectronics;Uses a top-down approach to understanding the neural activation proc...

Swelling of rat hepatocytes stimulates glycogen synthesis

NARCIS (Netherlands)

Baquet, A.; Hue, L.; Meijer, A. J.; van Woerkom, G. M.; Plomp, P. J.

1990-01-01

In hepatocytes from fasted rats, several amino acids are known to stimulate glycogen synthesis via activation of glycogen synthase. The hypothesis that an increase in cell volume resulting from amino acid uptake may be involved in the stimulation of glycogen synthesis is supported by the following

Human transient response under local thermal stimulation

Directory of Open Access Journals (Sweden)

Wang Lijuan

2017-01-01

Full Text Available Human body can operate physiological thermoregulation system when it is exposed to cold or hot environment. Whether it can do the same work when a local part of body is stimulated by different temperatures? The objective of this paper is to prove it. Twelve subjects are recruited to participate in this experiment. After stabilizing in a comfort environment, their palms are stimulated by a pouch of 39, 36, 33, 30, and 27°C. Subject’s skin temperature, heart rate, heat flux of skin, and thermal sensation are recorded. The results indicate that when local part is suffering from harsh temperature, the whole body is doing physiological thermoregulation. Besides, when the local part is stimulated by high temperature and its thermal sensation is warm, the thermal sensation of whole body can be neutral. What is more, human body is more sensitive to cool stimulation than to warm one. The conclusions are significant to reveal and make full use of physiological thermoregulation.

Evaluation of focused multipolar stimulation for cochlear implants: a preclinical safety study

Science.gov (United States)

Shepherd, Robert K.; Wise, Andrew K.; Enke, Ya Lang; Carter, Paul M.; Fallon, James B.

2017-08-01

Objective. Cochlear implants (CIs) have a limited number of independent stimulation channels due to the highly conductive nature of the fluid-filled cochlea. Attempts to develop highly focused stimulation to improve speech perception in CI users includes the use of simultaneous stimulation via multiple current sources. Focused multipolar (FMP) stimulation is an example of this approach and has been shown to reduce interaction between stimulating channels. However, compared with conventional biphasic current pulses generated from a single current source, FMP is a complex stimulus that includes extended periods of stimulation before charge recovery is achieved, raising questions on whether chronic stimulation with this strategy is safe. The present study evaluated the long-term safety of intracochlear stimulation using FMP in a preclinical animal model of profound deafness. Approach. Six cats were bilaterally implanted with scala tympani electrode arrays two months after deafening, and received continuous unilateral FMP stimulation at levels that evoked a behavioural response for periods of up to 182 d. Electrode impedance, electrically-evoked compound action potentials (ECAPs) and auditory brainstem responses (EABRs) were monitored periodically over the course of the stimulation program from both the stimulated and contralateral control cochleae. On completion of the stimulation program cochleae were examined histologically and the electrode arrays were evaluated for evidence of platinum (Pt) corrosion. Main results. There was no significant difference in electrode impedance between control and chronically stimulated electrodes following long-term FMP stimulation. Moreover, there was no significant difference between ECAP and EABR thresholds evoked from control or stimulated cochleae at either the onset of stimulation or at completion of the stimulation program. Chronic FMP stimulation had no effect on spiral ganglion neuron (SGN) survival when compared with

Criminality among Rural Stimulant Users in the United States

Science.gov (United States)

Oser, Carrie; Leukefeld, Carl; Staton-Tindall, Michele; Duvall, Jamieson; Garrity, Thomas; Stoops, William; Falck, Russel; Wang, Jichuan; Carlson, Robert; Sexton, Rocky; Wright, Patricia; Booth, Brenda

2011-01-01

Despite the increase in media attention on "meth cooking" in rural areas of the United States, little is known about rural stimulant use--particularly, the criminality associated with stimulant use. Data were collected from community stimulant users in rural Ohio, Arkansas, and Kentucky (N = 709). Findings from three logistic regression…

Focal Hemodynamic Responses in the Stimulated Hemisphere During High-Definition Transcranial Direct Current Stimulation.

Science.gov (United States)

Muthalib, Makii; Besson, Pierre; Rothwell, John; Perrey, Stéphane

2017-07-17

High-definition transcranial direct current stimulation (HD-tDCS) using a 4 × 1 electrode montage has been previously shown using modeling and physiological studies to constrain the electric field within the spatial extent of the electrodes. The aim of this proof-of-concept study was to determine if functional near-infrared spectroscopy (fNIRS) neuroimaging can be used to determine a hemodynamic correlate of this 4 × 1 HD-tDCS electric field on the brain. In a three session cross-over study design, 13 healthy males received one sham (2 mA, 30 sec) and two real (HD-tDCS-1 and HD-tDCS-2, 2 mA, 10 min) anodal HD-tDCS targeting the left M1 via a 4 × 1 electrode montage (anode on C3 and 4 return electrodes 3.5 cm from anode). The two real HD-tDCS sessions afforded a within-subject replication of the findings. fNIRS was used to measure changes in brain hemodynamics (oxygenated hemoglobin integral-O 2 Hb int ) during each 10 min session from two regions of interest (ROIs) in the stimulated left hemisphere that corresponded to "within" (L in ) and "outside" (L out ) the spatial extent of the 4 × 1 electrode montage, and two corresponding ROIs (R in and R out ) in the right hemisphere. The ANOVA showed that both real anodal HD-tDCS compared to sham induced a significantly greater O 2 Hb int in the L in than L out ROIs of the stimulated left hemisphere; while there were no significant differences between the real and sham sessions for the right hemisphere ROIs. Intra-class correlation coefficients showed "fair-to-good" reproducibility for the left stimulated hemisphere ROIs. The greater O 2 Hb int "within" than "outside" the spatial extent of the 4 × 1 electrode montage represents a hemodynamic correlate of the electrical field distribution, and thus provides a prospective reliable method to determine the dose of stimulation that is necessary to optimize HD-tDCS parameters in various applications. © 2017 International Neuromodulation Society.

Motor cortex stimulation suppresses cortical responses to noxious hindpaw stimulation after spinal cord lesion in rats.

Science.gov (United States)

Jiang, Li; Ji, Yadong; Voulalas, Pamela J; Keaser, Michael; Xu, Su; Gullapalli, Rao P; Greenspan, Joel; Masri, Radi

2014-01-01

Motor cortex stimulation (MCS) is a potentially effective treatment for chronic neuropathic pain. The neural mechanisms underlying the reduction of hyperalgesia and allodynia after MCS are not completely understood. To investigate the neural mechanisms responsible for analgesic effects after MCS. We test the hypothesis that MCS attenuates evoked blood oxygen-level dependent signals in cortical areas involved in nociceptive processing in an animal model of chronic neuropathic pain. We used adult female Sprague-Dawley rats (n = 10) that received unilateral electrolytic lesions of the right spinal cord at the level of C6 (SCL animals). In these animals, we performed magnetic resonance imaging (fMRI) experiments to study the analgesic effects of MCS. On the day of fMRI experiment, 14 days after spinal cord lesion, the animals were anesthetized and epidural bipolar platinum electrodes were placed above the left primary motor cortex. Two 10-min sessions of fMRI were performed before and after a session of MCS (50 μA, 50 Hz, 300 μs, for 30 min). During each fMRI session, the right hindpaw was electrically stimulated (noxious stimulation: 5 mA, 5 Hz, 3 ms) using a block design of 20 s stimulation off and 20 s stimulation on. A general linear model-based statistical parametric analysis was used to analyze whole brain activation maps. Region of interest (ROI) analysis and paired t-test were used to compare changes in activation before and after MCS in these ROI. MCS suppressed evoked blood oxygen dependent signals significantly (Family-wise error corrected P cortex and the prefrontal cortex. These findings suggest that, in animals with SCL, MCS attenuates hypersensitivity by suppressing activity in the primary somatosensory cortex and prefrontal cortex. Copyright © 2014. Published by Elsevier Inc.

Comparing the Efficacy of Excitatory Transcranial Stimulation Methods Measuring Motor Evoked Potentials

Directory of Open Access Journals (Sweden)

Vera Moliadze

2014-01-01

Full Text Available The common aim of transcranial stimulation methods is the induction or alterations of cortical excitability in a controlled way. Significant effects of each individual stimulation method have been published; however, conclusive direct comparisons of many of these methods are rare. The aim of the present study was to compare the efficacy of three widely applied stimulation methods inducing excitability enhancement in the motor cortex: 1 mA anodal transcranial direct current stimulation (atDCS, intermittent theta burst stimulation (iTBS, and 1 mA transcranial random noise stimulation (tRNS within one subject group. The effect of each stimulation condition was quantified by evaluating motor-evoked-potential amplitudes (MEPs in a fixed time sequence after stimulation. The analyses confirmed a significant enhancement of the M1 excitability caused by all three types of active stimulations compared to sham stimulation. There was no significant difference between the types of active stimulations, although the time course of the excitatory effects slightly differed. Among the stimulation methods, tRNS resulted in the strongest and atDCS significantly longest MEP increase compared to sham. Different time courses of the applied stimulation methods suggest different underlying mechanisms of action. Better understanding may be useful for better targeting of different transcranial stimulation techniques.

Broadband stimulated Raman spectroscopy in the deep ultraviolet region

Science.gov (United States)

Kuramochi, Hikaru; Fujisawa, Tomotsumi; Takeuchi, Satoshi; Tahara, Tahei

2017-09-01

We report broadband stimulated Raman measurements in the deep ultraviolet (DUV) region, which enables selective probing of the aromatic amino acid residues inside proteins through the resonance enhancement. We combine the narrowband DUV Raman pump pulse (1000 cm-1) to realize stimulated Raman measurements covering a >1500 cm-1 spectral window. The stimulated Raman measurements for neat solvents, tryptophan, tyrosine, and glucose oxidase are performed using 240- and 290-nm Raman pump, highlighting the high potential of the DUV stimulated Raman probe for femtosecond time-resolved study of proteins.

Sensory adaptation to electrical stimulation of the somatosensory nerves.

Science.gov (United States)

Graczyk, Emily Lauren; Delhaye, Benoit; Schiefer, Matthew A; Bensmaia, Sliman J; Tyler, Dustin J

2018-03-19

Sensory systems adapt their sensitivity to ambient stimulation levels to improve their responsiveness to changes in stimulation. The sense of touch is also subject to adaptation, as evidenced by the desensitization produced by prolonged vibratory stimulation of the skin. Electrical stimulation of nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial touch is also subject to adaptation, despite the fact that the peripheral mechanotransducers are bypassed. Approach: Using well-established psychophysical paradigms, we characterize the time course and magnitude of sensory adaptation caused by extended electrical stimulation of the residual somatosensory nerves in three human amputees implanted with cuff electrodes. Main results: We find that electrical stimulation of the nerve also induces perceptual adaptation that recovers after cessation of the stimulus. The time course and magnitude of electrically-induced adaptation are equivalent to their mechanically-induced counterparts. Significance: We conclude that, in natural touch, the process of mechanotransduction is not required for adaptation, and artificial touch naturally experiences adaptation-induced adjustments of the dynamic range of sensations. Further, as it does for native hands, adaptation confers to bionic hands enhanced sensitivity to changes in stimulation and thus a more natural sensory experience. . Creative Commons Attribution license.

A Fully Implantable Stimulator With Wireless Power and Data Transmission for Experimental Investigation of Epidural Spinal Cord Stimulation.

Science.gov (United States)

Xu, Qi; Hu, Dingyin; Duan, Bingyu; He, Jiping

2015-07-01

Epidural spinal cord stimulation (ESCS) combined with partial weight-bearing therapy (PWBT) has been shown to facilitate recovery of functional walking for individuals after spinal cord injury (SCI). The investigation of neural mechanisms of recovery from SCI under this treatment has been conducted broadly in rodent models, yet a suitable ESCS system is still unavailable. This paper describes a practical, programmable, and fully implantable stimulator for laboratory research on rats to explore fundamental neurophysiological principles for functional recovery after SCI. The ESCS system is composed of a personal digital assistant (PDA), an external controller, an implantable pulse generator (IPG), lead extension, and stimulating electrodes. The stimulation parameters can be programmed and adjusted through a graphical user interface on the PDA. The external controller is placed on the rat back and communicates with the PDA via radio-frequency (RF) telemetry. An RF carrier from the class-E power amplifier in the external controller provides both data and power for the IPG through an inductive link. The IPG is built around a microcontroller unit to generate voltage-regulated pulses delivered to the bipolar electrode for ESCS in rats. The encapsulated IPG measures 22 mm × 23 mm × 7 mm with a mass of  ∼  3.78 g. This fully implantable batteryless stimulator provided a simplified and efficient method to carry out chronic experiments in untethered animals for medical electro-neurological research.

Magnetic fields in noninvasive brain stimulation.

Science.gov (United States)

Vidal-Dourado, Marcos; Conforto, Adriana Bastos; Caboclo, Luis Otávio Sales Ferreira; Scaff, Milberto; Guilhoto, Laura Maria de Figueiredo Ferreira; Yacubian, Elza Márcia Targas

2014-04-01

The idea that magnetic fields could be used therapeutically arose 2000 years ago. These therapeutic possibilities were expanded after the discovery of electromagnetic induction by the Englishman Michael Faraday and the American Joseph Henry. In 1896, Arsène d'Arsonval reported his experience with noninvasive brain magnetic stimulation to the scientific French community. In the second half of the 20th century, changing magnetic fields emerged as a noninvasive tool to study the nervous system and to modulate neural function. In 1985, Barker, Jalinous, and Freeston presented transcranial magnetic stimulation, a relatively focal and painless technique. Transcranial magnetic stimulation has been proposed as a clinical neurophysiology tool and as a potential adjuvant treatment for psychiatric and neurologic conditions. This article aims to contextualize the progress of use of magnetic fields in the history of neuroscience and medical sciences, until 1985.

Pathways of translation: deep brain stimulation.

Science.gov (United States)

Gionfriddo, Michael R; Greenberg, Alexandra J; Wahegaonkar, Abhijeet L; Lee, Kendall H

2013-12-01

Electrical stimulation of the brain has a 2000 year history. Deep brain stimulation (DBS), one form of neurostimulation, is a functional neurosurgical approach in which a high-frequency electrical current stimulates targeted brain structures for therapeutic benefit. It is an effective treatment for certain neuropathologic movement disorders and an emerging therapy for psychiatric conditions and epilepsy. Its translational journey did not follow the typical bench-to-bedside path, but rather reversed the process. The shift from ancient and medieval folkloric remedy to accepted medical practice began with independent discoveries about electricity during the 19th century and was fostered by technological advances of the 20th. In this paper, we review that journey and discuss how the quest to expand its applications and improve outcomes is taking DBS from the bedside back to the bench. © 2013 Wiley Periodicals, Inc.

Strigolactones Stimulate Arbuscular Mycorrhizal Fungi by Activating Mitochondria

Science.gov (United States)

Besserer, Arnaud; Puech-Pagès, Virginie; Kiefer, Patrick; Gomez-Roldan, Victoria; Jauneau, Alain; Roy, Sébastien; Portais, Jean-Charles; Roux, Christophe; Bécard, Guillaume

2006-01-01

The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10 −13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants. PMID:16787107

Strigolactones stimulate arbuscular mycorrhizal fungi by activating mitochondria.

Directory of Open Access Journals (Sweden)

Arnaud Besserer

2006-07-01

Full Text Available The association of arbuscular mycorrhizal (AM fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10(-13 M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants.

Stimulant ADHD medication and risk for substance abuse.

Science.gov (United States)

Chang, Zheng; Lichtenstein, Paul; Halldner, Linda; D'Onofrio, Brian; Serlachius, Eva; Fazel, Seena; Långström, Niklas; Larsson, Henrik

2014-08-01

There are persistent concerns of long-term effects of stimulant ADHD medication on the development of substance abuse. Using Swedish national registers, we studied all individuals born between 1960 and 1998 and diagnosed with ADHD (26,249 men and 12,504 women). We investigated the association between stimulant ADHD medication in 2006 and substance abuse during 2009. Substance abuse was indexed by substance-related death, crime, or hospital visits. ADHD medication was not associated with increased rate of substance abuse. Actually, the rate during 2009 was 31% lower among those prescribed ADHD medication in 2006, even after controlling for medication in 2009 and other covariates (hazard ratio: 0.69; 95% confidence interval: 0.57-0.84). Also, the longer the duration of medication, the lower the rate of substance abuse. Similar risk reductions were suggested among children and when investigating the association between stimulant ADHD medication and concomitant short-term abuse. We found no indication of increased risks of substance abuse among individuals prescribed stimulant ADHD medication; if anything, the data suggested a long-term protective effect on substance abuse. Although stimulant ADHD medication does not seem to increase the risk for substance abuse, clinicians should remain alert to the potential problem of stimulant misuse and diversion in ADHD patients. © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.

Self-Rated Attentiveness Interacts with Transcranial Direct Current Stimulation and Noise Stimulation in Reaction Time in a Go/No-Go Task.

Science.gov (United States)

Sikström, Sverker; Jürgensen, Anna-Maria; Haghighi, Maryam; Månsson, Daniel; Smidelik, David; Habekost, Thomas

2016-01-01

Previous research has found that stimulating inattentive people with auditory white noise induces enhancement in cognitive performance. This enhancement is believed to occur due to a statistical phenomenon called stochastic resonance, where noise increases the probability of a signal passing the firing threshold in the neural cells. Here we investigate whether people with low attentiveness benefit to a larger extent than attentive people from stimulation by auditory white noise and transcranial direct current stimulation (tDCS). The results show, for both auditory noise and tDCS stimulation, that the changes in performance relative to nonstimulation correlate with the degree of attentiveness in a Go/No-Go task, but not in a N-back task. These results suggest that the benefit of tDCS may interact with inattentiveness.

Palatoglossus coupling in selective upper airway stimulation.

Science.gov (United States)

Heiser, Clemens; Edenharter, Günther; Bas, Murat; Wirth, Markus; Hofauer, Benedikt

2017-10-01

Selective upper airway stimulation (sUAS) of the hypoglossal nerve is a useful therapy to treat patients with obstructive sleep apnea. Is it known that multiple obstructions can be solved by this stimulation technique, even at the retropalatal region. The aim of this study was to verify the palatoglossus coupling at the soft palate during stimulation. Single-center, prospective clinical trail. Twenty patients who received an sUAS implant from April 2015 to April 2016 were included. A drug-induced sedated endoscopy (DISE) was performed before surgery. Six to 12 months after activation of the system, patients' tongue motions were recorded, an awake transnasal endoscopy was performed with stimulation turned on, and a DISE with stimulation off and on was done. Patients with a bilateral protrusion of the tongue base showed a significantly increased opening at the retropalatal level compared to ipsilateral protrusions. Furthermore, patients with a clear activation of the geniohyoid muscle showed a better reduction in apnea-hypopnea index. A bilateral protrusion of the tongue base during sUAS seems to be accompanied with a better opening of the soft palate. This effect can be explained by the palatoglossal coupling, due to its linkage of the muscles within the soft palate to those of the lateral tongue body. 4 Laryngoscope, 127:E378-E383, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Outcomes in spasticity after repetitive transcranial magnetic and transcranial direct current stimulations

OpenAIRE

Gunduz, Aysegul; Kumru, Hatice; Pascual-Leone, Alvaro

2014-01-01

Non-invasive brain stimulations mainly consist of repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Repetitive transcranial magnetic stimulation exhibits satisfactory outcomes in improving multiple sclerosis, stroke, spinal cord injury and cerebral palsy-induced spasticity. By contrast, transcranial direct current stimulation has only been studied in post-stroke spasticity. To better validate the efficacy of non-invasive brain stimulations in improving ...

Psychophysical Evaluation of Subdermal Electrical Stimulation in Relation to Prosthesis Sensory Feedback.

Science.gov (United States)

Geng, Bo; Dong, Jian; Jensen, Winnie; Dosen, Strahinja; Farina, Dario; Kamavuako, Ernest Nlandu

2018-03-01

This paper evaluated the psychophysical properties of subdermal electrical stimulation to investigate its feasibility in providing sensory feedback for limb prostheses. The detection threshold (DT), pain threshold (PT), just noticeable difference (JND), as well as the elicited sensation quality, comfort, intensity, and location were assessed in 16 healthy volunteers during stimulation of the ventral and dorsal forearm with subdermal electrodes. Moreover, the results were compared with those obtained from transcutaneous electrical stimulation. Despite a lower DT and PT, subdermal stimulation attained a greater relative dynamic range (i.e., PT/DT) and significantly smaller JNDs for stimulation amplitude. Muscle twitches and movements were more commonly elicited by surface stimulation, especially at the higher stimulation frequencies, whereas the pinprick sensation was more often reported with subdermal stimulation. Less comfort was perceived in subdermal stimulation of the ventral forearm at the highest tested stimulation frequency of 100 Hz. In summary, subdermal electrical stimulation was demonstrated to be able to produce similar sensation quality as transcutaneous stimulation and outperformed the latter in terms of energy efficiency and sensitivity. These results suggest that stimulation through implantable subdermal electrodes may lead to an efficient and compact sensory feedback system for substituting the lost sense in amputees.

Auditory beat stimulation and its effects on cognition and mood states

Directory of Open Access Journals (Sweden)

Leila eChaieb

2015-05-01

Full Text Available Auditory beat stimulation may be a promising new tool for the manipulation of cognitive processes and the modulation of mood-states. Here we aim to review the literature examining the most current applications of auditory beat stimulation and its targets. We give a brief overview of research on auditory steady-state responses and its relationship to auditory beat stimulation. We have summarized relevant studies investigating the neurophysiological changes related to auditory beat stimulation and how they impact upon the design of appropriate stimulation protocols. Focusing on binaural beat stimulation, we then discuss the role of monaural and binaural beat frequencies in cognition and mood-states, in addition to their efficacy in targeting disease symptoms. We aim to highlight important points concerning stimulation parameters and try to address why there are often contradictory findings with regard to the outcomes of auditory beat stimulation.

Spinal cord stimulation therapy for localized central pain

International Nuclear Information System (INIS)

Hirato, Masafumi; Takahashi, Akio; Watanabe, Katsushige; Kazama, Ken; Yoshimoto, Yuhei

2008-01-01

We studied the pathophysiology of localized central pain and the surgical result of spinal cord stimulation. There were 10 cases; 7 males and 3 females from 24 to 77 years old. Pain was caused by peripheral nerve injury in one case, spinal cord injury in two cases and cerebrovascular disease (CVD) (thalamic pain) in 7 cases. All cases were treated by epidural spinal cord stimulation and followed from 0.8 to 8.8 years. Sufficient pain relief was achieved in one case of peripheral nerve and spinal cord injury and in 4 cases of CVD. Moderate pain control was achieved in 2 cases of CVD. In one each case of spinal cord injury and of CVD, pain control was ineffective. In cases with thalamic pain, we studied the correlation between the surgical result of spinal cord stimulation and the clinical features, MRI, fluoro-deoxyglucose (FDG)-positron emission tomography (PET), and somatosensory evoked potentials (SEP) findings before operation. MRI revealed a small to moderate sized lesion on the thalamus or putamen in each case. PET also showed decreased accumulation of FDG on the affected thalamus. In all cases without one fair responder to spinal cord stimulation, we could recognize definite SEP originating in the sensory cortex ipsilateral side to the CVD lesion during contralateral median or posterior tibial nerve stimulation. In the good responders, we could recognize SEP originating in the sensory cortex of the lesion side with less delayed latency or decreased amplitude than in the moderate responders. In this group, test stimulation with low voltage on the spinal cord evoked a sensory effect (paresthesia) over the painful part of the body. Spinal cord stimulation proved to be an effective treatment for localized central pain. In cases with localized central pain after CVD, we could expect to ameliorate the intractable pain in those cases in which SEP or spinal cord test stimulation revealed that the thalamo-cortical system was preserved. (author)

Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

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Tonya M Moloney

Full Text Available BACKGROUND: The primary motor cortex (M1 is an effective target of non-invasive cortical stimulation (NICS for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. OBJECTIVE: Here we investigate whether transcranial direct current stimulation (tDCS primed 1 Hz repetitive transcranial magnetic stimulation (rTMS modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. METHOD: 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. RESULTS: Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (p<0.001 with a parallel increase in pressure pain thresholds (p<0.01. In contrast, anodal tDCS-primed 1 Hz-rTMS resulted in a corresponding decrease in cortical excitability (p<0.05, with no significant effect on pressure pain. CONCLUSION: This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

21 CFR 340.10 - Stimulant active ingredient.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Stimulant active ingredient. 340.10 Section 340.10 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE STIMULANT DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE Active Ingredient § 340.10...

A Microfabricated Transduction Coil for Inductive Deep Brain Stimulation

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Jie (Jayne WU

2006-07-01

Full Text Available "Inductively Coupled Deep Brain Stimulator" describes a chip/system design to inductively couple arbitrary waveforms to electrodes embedded in the brain for deep brain stimulation or other neurostimulation. This approach moves the conventionally implanted signal generator outside the body and provides flexibility in adjusting waveforms to investigate optimum stimulation waveforms. An "inlaid electroplating" process with through-wafer plating is used to reduce microcoil resistance and integrate microstructures and electronics. Utilizing inductive link resonance specific to microcoils, waveforms are selectively transmitted to microcoils, which further produces biphasic waveforms that are suitable for deep brain stimulation.

Neuromuscular Electrical Stimulation for Mobility Support of Elderly.

Science.gov (United States)

Mayr, Winfried

2015-08-24

The stimulator for neuromuscular electrical stimulation for mobility support of elderly is not very complicated, but for application within "MOBIL" we have some additional demands to fulfill. First we have specific safety issues for this user group. A powerful compliance management system is crucial not only to guide daily application, but for creating hard data for the scientific outcome. We also need to assure easy handling of the stimulator, because the subjects are generally not able to cope with too difficult and complex motor skills. So, we developed five generations of stimulators and optimizing solutions after field tests. We are already planning the sixth generation with wireless control of the stimulation units by the central main handheld control unit. In a prototype, we have implemented a newly available high capacity memory, a breakthrough in "compliance data storage" as they offer the necessary high storage capacity and fast data handling for an affordable prize. The circuit also contains a 3D accelerometer sensor which acts as a further important safety features: if the control unit drops, this event is detected automatically by the sensor and activates an emergency switch-off that disables the stimulation to avoid associated risks. Further, we have implemented a hardware emergence shutdown and other safety measures. Finally, in the last example muscle torque measurements are referenced with compliance data. In the study normalized maximum voluntary contraction (MVC) and maximum stimulation induced contraction (MSC) were assessed in regular check-ups along the training period. With additional consideration of adjusted stimulation intensity for training out of the compliance data records we are able to estimate the induced contraction strength, which turned out to amount in average 11% of MVC. This value may seem on a first sight rather low, and ought to be considered in relation to the results at the end of the training period. Therefore the

Neuromuscular electrical stimulation for mobility support of elderly

Directory of Open Access Journals (Sweden)

Winfried Mayr

2015-10-01

Full Text Available The stimulator for neuromuscular electrical stimulation for mobility support of elderly is not very complicated, but for application within "MOBIL" we have some additional demands to fulfill. First we have specific safety issues for this user group. A powerful compliance management system is crucial not only to guide daily application, but for creating hard data for the scientific outcome. We also need to assure easy handling of the stimulator, because the subjects are generally not able to cope with too difficult and complex motor skills. So, we developed five generations of stimulators and optimizing solutions after field tests. We are already planning the sixth generation with wireless control of the stimulation units by the central main handheld control unit. In a prototype, we have implemented a newly available high capacity memory, a breakthrough in “compliance data storage” as they offer the necessary high storage capacity and fast data handling for an affordable prize. The circuit also contains a 3D accelerometer sensor which acts as a further important safety features: if the control unit drops, this event is detected automatically by the sensor and activates an emergency switch-off that disables the stimulation to avoid associated risks. Further, we have implemented a hardware emergence shutdown and other safety measures. Finally, in the last example muscle torque measurements are referenced with compliance data. In the study normalized maximum voluntary contraction (MVC and maximum stimulation induced contraction (MSC were assessed in regular check-ups along the training period. With additional consideration of adjusted stimulation intensity for training out of the compliance data records we are able to estimate the induced contraction strength, which turned out to amount in average 11% of MVC. This value may seem on a first sight rather low, and ought to be considered in relation to the results at the end of the training period

Autistic spectrum disorder, epilepsy, and vagus nerve stimulation.

Science.gov (United States)

Hull, Mariam Mettry; Madhavan, Deepak; Zaroff, Charles M

2015-08-01

In individuals with a comorbid autistic spectrum disorder and medically refractory epilepsy, vagus nerve stimulation may offer the potential of seizure control and a positive behavioral side effect profile. We aimed to examine the behavioral side effect profile using longitudinal and quantitative data and review the potential mechanisms behind behavioral changes. We present a case report of a 10-year-old boy with autistic spectrum disorder and epilepsy, who underwent vagus nerve stimulation subsequent to unsuccessful treatment with antiepileptic medication. Following vagus nerve stimulation implantation, initial, if temporary, improvement was observed in seizure control. Modest improvements were also observed in behavior and development, improvements which were observed independent of seizure control. Vagus nerve stimulation in autistic spectrum disorder is associated with modest behavioral improvement, with unidentified etiology, although several candidates for this improvement are evident.

Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

Science.gov (United States)

Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

2016-01-01

Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (cyborg insects or biobots.

Electrical stimulation in dysphagia treatment: a justified controversy?

NARCIS (Netherlands)

Bogaardt, H. C. A.

2008-01-01

Electrical stimulation in dysphagia treatment: a justified controversy? Neuromuscular electrostimulation (LAMES) is a method for stimulating muscles with short electrical pulses. Neuromuscular electrostimulation is frequently used in physiotherapy to strengthen healthy muscles (as in sports

Vagus nerve stimulation magnet activation for seizures: a critical review.

Science.gov (United States)

Fisher, R S; Eggleston, K S; Wright, C W

2015-01-01

Some patients receiving VNS Therapy report benefit from manually activating the generator with a handheld magnet at the time of a seizure. A review of 20 studies comprising 859 subjects identified patients who reported on-demand magnet mode stimulation to be beneficial. Benefit was reported in a weighted average of 45% of patients (range 0-89%) using the magnet, with seizure cessation claimed in a weighted average of 28% (range 15-67%). In addition to seizure termination, patients sometimes reported decreased intensity or duration of seizures or the post-ictal period. One study reported an isolated instance of worsening with magnet stimulation (Arch Pediatr Adolesc Med, 157, 2003 and 560). All of the reviewed studies assessed adjunctive magnet use. No studies were designed to provide Level I evidence of efficacy of magnet-induced stimulation. Retrospective analysis of one pivotal randomized trial of VNS therapy showed significantly more seizures terminated or improved in the active stimulation group vs the control group. Prospective, controlled studies would be required to isolate the effect and benefit of magnet mode stimulation and to document that the magnet-induced stimulation is the proximate cause of seizure reduction. Manual application of the magnet to initiate stimulation is not always practical because many patients are immobilized or unaware of their seizures, asleep or not in reach of the magnet. Algorithms based on changes in heart rate at or near the onset of the seizure provide a methodology for automated responsive stimulation. Because literature indicates additional benefits from on-demand magnet mode stimulation, a potential role exists for automatic activation of stimulation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Collegiate misuse of prescription stimulants: examining differences in self-worth.

Science.gov (United States)

Giordano, Amanda L; Prosek, Elizabeth A; Reader, Emily A; Bevly, Cynthia M; Turner, Kori D; LeBlanc, Yvette N; Vera, Ryan A; Molina, Citlali E; Garber, Sage Ann

2015-02-01

Prescription stimulant medication is commonly used to treat attention-deficit hyperactivity disorder (ADHD). However, stimulant medication misuse is a prevalent problem among the college population. There is limited research on psychological factors associated with collegiate nonmedical stimulant misuse. To examine the association between college students' self-worth and stimulant medication misuse. A quantitative study implemented during the 2013-2014 academic year in which we utilized a convenience sample of undergraduate students at a public university. College students (N = 3,038) completed an electronic survey packet including a stimulant use index and the Contingencies of Self-Worth Scale. We conducted descriptive discriminant analysis (DDA) to measure the associations between four groups: Nonusers, Appropriate Users, Nonprescribed Misusuers, and Prescribed Users. Significant differences in contingencies of self-worth existed between the four groups of students. Specifically, external contingencies of self-worth, such as appearance and approval, were associated with stimulant medication misuse, whereas, internal contingencies of self-worth, such as God's love and virtue, were associated with nonuse and appropriate prescribed use. Conclusions/Importance: The findings of the current study suggested contingencies of self-worth partially explain prescription stimulant misuse among the collegiate population. Addressing self-worth may be helpful in the treatment of stimulant misuse with college students.

Galvanic Vestibular Stimulation in Hemi-Spatial Neglect

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David eWilkinson

2014-01-01

Full Text Available Hemi-spatial neglect is an attentional disorder in which the sufferer fails to acknowledge or respond to stimuli appearing in contralesional space. In recent years, it has become clear that a measurable reduction in contralesional neglect can occur during galvanic vestibular stimulation, a technique by which transmastoid, small amplitude current induces lateral, attentional shifts via asymmetric modulation of the left and right vestibular nerves. However, it remains unclear whether this reduction persists after stimulation is stopped. To estimate longevity of effect, we therefore conducted a double-blind, randomized, dose-response trial involving a group of stroke patients suffering from left-sided neglect (n=52, mean age=66 years. To determine whether repeated sessions of galvanic vestibular stimulation more effectively induce lasting relief than a single session, participants received 1, 5, or 10 sessions, each lasting 25mins, of sub-sensory, left-anodal right-cathodal noisy direct current (mean amplitude=1mA. Ninety five percent confidence intervals indicated that all three treatment arms showed a statistically significant improvement between the pre-stimulation baseline and the final day of stimulation on the primary outcome measure, the conventional tests of the Behavioural Inattention Test. More remarkably, this change (mean change=28%, SD=18 was still evident 1month later. Secondary analyses indicated an allied increase of 20% in median Barthel Index score, a measure of functional capacity, in the absence of any adverse events or instances of participant non-compliance. Together these data suggest that galvanic vestibular stimulation, a simple, cheap technique suitable for home-based administration, may produce lasting reductions in neglect that are clinically important. Further protocol optimization is now needed ahead of a larger effectiveness study.

Galvanic vestibular stimulation speeds visual memory recall.

Science.gov (United States)

Wilkinson, David; Nicholls, Sophie; Pattenden, Charlotte; Kilduff, Patrick; Milberg, William

2008-08-01

The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However, several neuropsychological studies have shown that much weaker, imperceptible currents that do not elicit unpleasant side-effects can help overcome visual loss after stroke. Here, we show that visual processing in neurologically healthy individuals can also benefit from galvanic vestibular stimulation. Participants first learnt the names of eight unfamiliar faces and then after a short delay, answered questions from memory about how pairs of these faces differed. Mean correct reaction times were significantly shorter when sub-sensory, noise-enhanced anodal stimulation was administered to the left mastoid, compared to when no stimulation was administered at all. This advantage occurred with no loss in response accuracy, and raises the possibility that the procedure may constitute a more general form of cognitive enhancement.

Comparison of the shock artifacts induced by tripolar and bipolar electrical stimulation techniques.

Science.gov (United States)

Wee, A S; Jiles, K; Brennan, R

2001-01-01

Tripolar and bipolar electrical stimulation procedures were performed on the upper limbs of eight subjects. The mid-forearm was stimulated electrically (tripolar or bipolar) by surface electrodes, and the induced stimulus shock artifacts were recorded simultaneously from the wrist and elbow. During tripolar stimulation, two types of stimulating configurations were utilized: with the center electrode designated as the cathode and the two outermost electrodes connected to a common anode, and vice versa. During bipolar stimulation, the center electrode served as one pole of the stimulator, and one of the two outermost electrodes of the tripolar stimulator was disconnected. The stimulus intensity was kept constant in all stimulating procedures. Artifacts were reduced significantly during tripolar compared to bipolar stimulation, if the outermost electrodes of the tripolar stimulator (which were facing the recording electrodes) were also oriented toward the recording sites during bipolar stimulation and had the same stimulus polarity. Artifacts were slightly reduced in amplitude from tripolar stimulation, if the center electrode were oriented toward the recording sites during bipolar stimulation and had the same stimulus polarity as previously used during tripolar stimulation.

Activation of sensory cortex by imagined genital stimulation: an fMRI analysis.

Science.gov (United States)

Wise, Nan J; Frangos, Eleni; Komisaruk, Barry R

2016-01-01

During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. This study extends our previous findings by further characterizing how the brain differentially processes physical 'touch' stimulation and 'imagined' stimulation. Eleven healthy women (age range 29-74) participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions - imagined dildo self-stimulation and imagined speculum stimulation - were included to characterize the effects of erotic versus non-erotic imagery. Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex) and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region), and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the 'reward system'. In addition, these results suggest a mechanism by which some individuals may

Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

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Nan J. Wise

2016-10-01

Full Text Available Background: During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. Objective: This study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation. Design: Eleven healthy women (age range 29–74 participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery. Results: Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region, and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. Conclusion: The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the �

21 CFR 882.5870 - Implanted peripheral nerve stimulator for pain relief.

Science.gov (United States)

2010-04-01

....5870 Implanted peripheral nerve stimulator for pain relief. (a) Identification. An implanted peripheral nerve stimulator for pain relief is a device that is used to stimulate electrically a peripheral nerve... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted peripheral nerve stimulator for pain...

Well screening for matrix stimulation treatments

International Nuclear Information System (INIS)

Saavedra, N; Solano, R; Gidley, J; Reyes, C.A; Rodriguez; Kondo, F; Hernandez, J

1998-01-01

Matrix acidizing is a stimulation technique only applicable to wells with surrounding damage. It is therefore very important to differentiate the real formation damage from the damage caused by flow Ni dynamic effects. The mechanical damage corresponds to flow restrictions caused by partial penetration, poor perforation as well as to reduce diameters of the production tubing. The dynamic effects are generated by inertia caused by high flow rates and high-pressure differentials. A common practice in our oil fields is to use a general formulation as acid treatment, most of the times without previous lab studies that guarantee the applicability of the treatment in the formation. Additionally, stimulation is randomly applied even treating undamaged wells with negative results and in the best of the cases, loss of the treatment. The selection of the well for matrix stimulation is an essential factor for the success of the treatment. Selection is done through the evaluation of the skin factor (S) and of the economic benefits of reducing the skin in comparison to the cost of the work. The most appropriate tool for skin evaluation is a good pressure test where the radial flow period can be identified. Nevertheless, we normally find-outdated tests most of the times taken with inaccurate tools. The interpretation problem is worsened by completions in which there is simultaneous production from several sand packages and it is difficult to individually differentiate damage factors. This works states a procedure for the selection of wells appropriate for stimulation; it also proposes a method to evaluate the skin factor when there are no accurate interpretations of the pressure tests. A new and increasingly applied methodology to treat wells with high water cuts, which are usually discarded due to the risk of stimulating water zones, is also mentioned

Proinflammatory mediators stimulate neutrophil-directed angiogenesis.

LENUS (Irish Health Repository)

McCourt, M

2012-02-03

BACKGROUND: Vascular endothelial growth factor (VEGF; vascular permeability factor) is one of the most potent proangiogenic cytokines, and it plays a central role in mediating the process of angiogenesis or new blood vessel formation. Neutrophils (PMNs) recently have been shown to produce VEGF. HYPOTHESIS: The acute inflammatory response is a potent stimulus for PMN-directed angiogenesis. METHODS: Neutrophils were isolated from healthy volunteers and stimulated with lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and anti-human Fas monoclonal antibody. Culture supernatants were assayed for VEGF using enzyme-linked immunosorbent assays. Culture supernatants from LPS- and TNF-alpha-stimulated PMNs were then added to human umbilical vein endothelial cells and human microvessel endothelial cells and assessed for endothelial cell proliferation using 5-bromodeoxyuridine labeling. Tubule formation was also assessed on MATRIGEL basement membrane matrix. Neutrophils were lysed to measure total VEGF release, and VEGF expression was detected using Western blot analysis. RESULTS: Lipopolysaccharide and TNF-alpha stimulation resulted in significantly increased release of PMN VEGF (532+\\/-49 and 484+\\/-80 pg\\/mL, respectively; for all, presented as mean +\\/- SEM) compared with control experiments (32+\\/-4 pg\\/mL). Interleukin 6 and Fas had no effect. Culture supernatants from LPS- and TNF-alpha-stimulated PMNs also resulted in significant increases (P<.005) in macrovascular and microvascular endothelial cell proliferation and tubule formation. Adding anti-human VEGF-neutralizing polyclonal antibody to stimulated PMN supernatant inhibited these effects. Total VEGF release following cell lysis and Western blot analysis suggests that the VEGF is released from an intracellular store. CONCLUSION: Activated human PMNs are directly angiogenic by releasing VEGF, and this has important implications for inflammation, capillary leak syndrome

Inhibition of stimulated Raman scattering due to the excitation of stimulated Brillouin scattering

Science.gov (United States)

Zhao, Yao; Yu, Lu-Le; Weng, Su-Ming; Ren, Chuang; Liu, Chuan-Sheng; Sheng, Zheng-Ming

2017-09-01

The nonlinear coupling between stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) of intense laser in underdense plasma is studied theoretically and numerically. Based upon the fluid model, their coupling equations are derived, and a threshold condition of plasma density perturbations due to SBS for the inhibition of SRS is given. Particle-in-cell simulations show that this condition can be achieved easily by SBS in the so-called fluid regime with kLλDDebye length [Kline et al., Phys. Plasmas 13, 055906 (2006)]. SBS can reduce the saturation level of SRS and the temperature of electrons in both homogeneous and inhomogeneous plasma. Numerical simulations also show that this reduced SRS saturation is retained even if the fluid regime condition mentioned above is violated at a later time due to plasma heating.

Recruitment order of quadriceps motor units: femoral nerve vs. direct quadriceps stimulation.

Science.gov (United States)

Rodriguez-Falces, Javier; Place, Nicolas

2013-12-01

To investigate potential differences in the recruitment order of motor units (MUs) in the quadriceps femoris when electrical stimulation is applied over the quadriceps belly versus the femoral nerve. M-waves and mechanical twitches were evoked using femoral nerve stimulation and direct quadriceps stimulation of gradually increasing intensity from 20 young, healthy subjects. Recruitment order was investigated by analysing the time-to-peak twitch and the time interval from the stimulus artefact to the M-wave positive peak (M-wave latency) for the vastus medialis (VM) and vastus lateralis (VL) muscles. During femoral nerve stimulation, time-to-peak twitch and M-wave latency decreased consistently (P  0.05). For the VM muscle, M-wave latency decreased with increasing stimulation level for both femoral nerve and direct quadriceps stimulation, whereas, for the VL muscle, the variation of M-wave latency with stimulus intensity was different for the two stimulation geometries (P recruitment order during direct quadriceps stimulation was more complex, depending ultimately on the architecture of the peripheral nerve and its terminal branches below the stimulating electrodes for each muscle. For the VM, MUs were orderly recruited for both stimulation geometries, whereas, for the VL muscle, MUs were orderly recruited for femoral nerve stimulation, but followed no particular order for direct quadriceps stimulation.

Network-targeted cerebellar transcranial magnetic stimulation improves attentional control

Science.gov (United States)

Esterman, Michael; Thai, Michelle; Okabe, Hidefusa; DeGutis, Joseph; Saad, Elyana; Laganiere, Simon E.; Halko, Mark A.

2018-01-01

Developing non-invasive brain stimulation interventions to improve attentional control is extremely relevant to a variety of neurologic and psychiatric populations, yet few studies have identified reliable biomarkers that can be readily modified to improve attentional control. One potential biomarker of attention is functional connectivity in the core cortical network supporting attention - the dorsal attention network (DAN). We used a network-targeted cerebellar transcranial magnetic stimulation (TMS) procedure, intended to enhance cortical functional connectivity in the DAN. Specifically, in healthy young adults we administered intermittent theta burst TMS (iTBS) to the midline cerebellar node of the DAN and, as a control, the right cerebellar node of the default mode network (DMN). These cerebellar targets were localized using individual resting-state fMRI scans. Participants completed assessments of both sustained (gradual onset continuous performance task, gradCPT) and transient attentional control (attentional blink) immediately before and after stimulation, in two sessions (cerebellar DAN and DMN). Following cerebellar DAN stimulation, participants had significantly fewer attentional lapses (lower commission error rates) on the gradCPT. In contrast, stimulation to the cerebellar DMN did not affect gradCPT performance. Further, in the DAN condition, individuals with worse baseline gradCPT performance showed the greatest enhancement in gradCPT performance. These results suggest that temporarily increasing functional connectivity in the DAN via network-targeted cerebellar stimulation can enhance sustained attention, particularly in those with poor baseline performance. With regard to transient attention, TMS stimulation improved attentional blink performance across both stimulation sites, suggesting increasing functional connectivity in both networks can enhance this aspect of attention. These findings have important implications for intervention applications

A long-lasting wireless stimulator for small mammals

Directory of Open Access Journals (Sweden)

Ian D Hentall

2013-10-01

Full Text Available The chronic effects of electrical stimulation in unrestrained awake rodents are best studied with a wireless neural stimulator that can operate unsupervised for several weeks or more. A robust, inexpensive, easily built, cranially implantable stimulator was developed to explore the restorative effects of brainstem stimulation after neurotrauma. Its connectorless electrodes directly protrude from a cuboid epoxy capsule containing all circuitry and power sources. This physical arrangement prevents fluid leaks or wire breakage and also simplifies and speeds implantation. Constant-current pulses of high compliance (34 volts are delivered from a step-up voltage regulator under microprocessor control. A slowly pulsed magnetic field controls activation state and stimulation parameters. Program status is signaled to a remote reader by interval-modulated infrared pulses. Capsule size is limited by the two batteries. Silver oxide batteries rated at 8 milliamp-hours were used routinely in 8 mm wide, 15 mm long and 4 mm high capsules. Devices of smaller contact area (5 by 12 mm but taller (6 mm were created for mice. Microstimulation of the rat’s raphe nuclei with intermittent 5-minute (50% duty cycle trains of 30 µA, 1 ms pulses at 8 or 24 Hz frequency during 12 daylight hours lasted 21.1 days ±0.8 (mean ± standard error, Kaplan-Meir censored estimate, n=128. Extended lifetimes (>6 weeks, no failures, n=16 were achieved with larger batteries (44 milliamp-hours in longer (18 mm, taller (6 mm capsules. The circuit and electrode design are versatile; simple modifications allowed durable constant-voltage stimulation of the rat’s sciatic nerve through a cylindrical cathode from a subcutaneous pelvic capsule. Devices with these general features can address in small mammals many of the biological and technical questions arising neurosurgically with prolonged peripheral or deep brain stimulation.

Penfield's prediction: a mechanism for deep brain stimulation

Directory of Open Access Journals (Sweden)

Richard W. Murrow

2014-10-01

Full Text Available (1Context: Despite its widespread use, the precise mechanism of action of Deep Brain Stimulation (DBS therapy remains unknown. The modern urgency to publish more and new data can obscure previously learned lessons by the giants who have preceded us and whose shoulders we now stand upon. Wilder Penfield extensively studied the effects of artificial electrical brain stimulation and his comments on the subject are still very relevant today. In particular, he noted two very different (and seemingly opposite effects of stimulation within the human brain. In some structures, artificial electrical stimulation has an effect which mimics ablation, while, in other structures, it produces a stimulatory effect on that tissue. (2Hypothesis:The hypothesis of this paper is fourfold. First, it proposes that some neural circuits are widely synchronized with other neural circuits, while some neural circuits are unsynchronized and operate independently. Second, it proposes that artificial high frequency electrical stimulation of a synchronized neural circuit results in an ablative effect, but artificial high frequency electrical stimulation of an unsynchronized neural circuit results in a stimulatory effect. Third, it suggests a part of the mechanism by which large scale physiologic synchronization of widely distributed independently processed information streams may occur. This may be the neural mechanism underlying Penfield’s centrencephalic system which he emphasized so many years ago. Fourth, it outlines the specific anatomic distribution of this physiologic synchronization, which Penfield has already clearly delineated as the distribution of his centrencephalic system. (3Evidence:This paper draws on a brief overview of previous theory regarding the mechanism of action of DBS and on historical, as well as widely known modern clinical data regarding the observed effects of stimulation delivered to various targets within the brain. Basic science in

Peripheral nerve recruitment curve using near-infrared stimulation

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Dautrebande, Marie; Doguet, Pascal; Gorza, Simon-Pierre; Delbeke, Jean; Nonclercq, Antoine

2018-02-01

In the context of near-infrared neurostimulation, we report on an experimental hybrid electrode allowing for simultaneous photonic or electrical neurostimulation and for electrical recording of evoked action potentials. The electrode includes three contacts and one optrode. The optrode is an opening in the cuff through which the tip of an optical fibre is held close to the epineurium. Two contacts provide action potential recording. The remaining contact, together with a remote subcutaneous electrode, is used for electric stimulation which allows periodical assessment of the viability of the nerve during the experiment. A 1470 nm light source was used to stimulate a mouse sciatic nerve. Neural action potentials were not successfully recorded because of the electrical noise so muscular activity was used to reflect the motor fibres stimulation. A recruitment curve was obtained by stimulating with photonic pulses of same power and increasing duration and recording the evoked muscular action potentials. Motor fibres can be recruited with radiant exposures between 0.05 and 0.23 J/cm2 for pulses in the 100 to 500 μs range. Successful stimulation at short duration and at a commercial wavelength is encouraging in the prospect of miniaturisation and practical applications. Motor fibres recruitment curve is a first step in an ongoing research work. Neural action potential acquisition will be improved, with aim to shed light on the mechanism of action potential initiation under photonic stimulation.

Human abuse liability evaluation of CNS stimulant drugs.

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Romach, Myroslava K; Schoedel, Kerri A; Sellers, Edward M

2014-12-01

Psychoactive drugs that increase alertness, attention and concentration and energy, while also elevating mood, heart rate and blood pressure are referred to as stimulants. Despite some overlapping similarities, stimulants cannot be easily categorized by their chemical structure, mechanism of action, receptor binding profile, effects on monoamine uptake, behavioral pharmacology (e.g., effects on locomotion, temperature, and blood pressure), therapeutic indication or efficacy. Because of their abuse liability, a pre-market assessment of abuse potential is required for drugs that show stimulant properties; this review article focuses on the clinical aspects of this evaluation. This includes clinical trial adverse events, evidence of diversion or tampering, overdoses and the results of a human abuse potential study. While there are different types of human experimental studies that can be employed to evaluate stimulant abuse potential (e.g., drug discrimination, self-administration), only the human abuse potential study and clinical trial adverse event data are required for drug approval. The principal advances that have improved human abuse potential studies include using study enrichment strategies (pharmacologic qualification), larger sample sizes, better selection of endpoints and measurement strategies and more carefully considered interpretation of data. Because of the methodological advances, comparisons of newer studies with historical data is problematic and may contribute to a biased regulatory framework for the evaluation of newer stimulant-like drugs, such as A2 antagonists. This article is part of the Special Issue entitled 'CNS Stimulants'. Copyright © 2014 Elsevier Ltd. All rights reserved.

21 CFR 882.5880 - Implanted spinal cord stimulator for pain relief.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted spinal cord stimulator for pain relief... Implanted spinal cord stimulator for pain relief. (a) Identification. An implanted spinal cord stimulator for pain relief is a device that is used to stimulate electrically a patient's spinal cord to relieve...

An intermediate animal model of spinal cord stimulation

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Thomas Guiho

2016-06-01

Full Text Available Spinal cord injuries (SCI result in the loss of movement and sensory feedback as well as organs dysfunctions. For example, nearly all SCI subjects loose their bladder control and are prone to kidney failure if they do not proceed to intermittent (self- catheterization. Electrical stimulation of the sacral spinal roots with an implantable neuroprosthesis is a promising approach, with commercialized products, to restore continence and control micturition. However, many persons do not ask for this intervention since a surgical deafferentation is needed and the loss of sensory functions and reflexes become serious side effects of this procedure. Recent results renewed interest in spinal cord stimulation. Stimulation of existing pre-cabled neural networks involved in physiological processes regulation is suspected to enable synergic recruitment of spinal fibers. The development of direct spinal stimulation strategies aiming at bladder and bowel functions restoration would therefore appear as a credible alternative to existent solutions. However, a lack of suitable large animal model complicates these kinds of studies. In this article, we propose a new animal model of spinal stimulation -pig- and will briefly introduce results from one first acute experimental validation session.

Uncovering the mechanism(s) of deep brain stimulation

International Nuclear Information System (INIS)

Li Gang; Yu Chao; Lin Ling; Lu, Stephen C-Y

2005-01-01

Deep brain stimulators, often called 'pacemakers for the brain', are implantable devices which continuously deliver impulse stimulation to specific targeted nuclei of deep brain structure, namely deep brain stimulation (DBS). To date, deep brain stimulation (DBS) is the most effective clinical technique for the treatment of several medically refractory movement disorders (e.g., Parkinson's disease, essential tremor, and dystonia). In addition, new clinical applications of DBS for other neurologic and psychiatric disorders (e.g., epilepsy and obsessive-compulsive disorder) have been put forward. Although DBS has been effective in the treatment of movement disorders and is rapidly being explored for the treatment of other neurologic disorders, the scientific understanding of its mechanisms of action remains unclear and continues to be debated in the scientific community. Optimization of DBS technology for present and future therapeutic applications will depend on identification of the therapeutic mechanism(s) of action. The goal of this review is to address our present knowledge of the effects of high-frequency stimulation within the central nervous system and comment on the functional implications of this knowledge for uncovering the mechanism(s) of DBS

STIMULATION TECHNOLOGIES FOR DEEP WELL COMPLETIONS

Energy Technology Data Exchange (ETDEWEB)

Stephen Wolhart

2003-06-01

The Department of Energy (DOE) is sponsoring a Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies is conducting a project to evaluate the stimulation of deep wells. The objective of the project is to assess U.S. deep well drilling & stimulation activity, review rock mechanics & fracture growth in deep, high pressure/temperature wells and evaluate stimulation technology in several key deep plays. Phase 1 was recently completed and consisted of assessing deep gas well drilling activity (1995-2007) and an industry survey on deep gas well stimulation practices by region. Of the 29,000 oil, gas and dry holes drilled in 2002, about 300 were drilled in the deep well; 25% were dry, 50% were high temperature/high pressure completions and 25% were simply deep completions. South Texas has about 30% of these wells, Oklahoma 20%, Gulf of Mexico Shelf 15% and the Gulf Coast about 15%. The Rockies represent only 2% of deep drilling. Of the 60 operators who drill deep and HTHP wells, the top 20 drill almost 80% of the wells. Six operators drill half the U.S. deep wells. Deep drilling peaked at 425 wells in 1998 and fell to 250 in 1999. Drilling is expected to rise through 2004 after which drilling should cycle down as overall drilling declines.

Stimulants for the control of hedonic appetite

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Alison Sally Poulton

2016-04-01

Full Text Available The focus of this paper is treatment of obesity in relation to the management of hedonic appetite. Obesity is a complex condition which may be potentiated by excessive reward seeking in combination with executive functioning deficits that impair cognitive control of behaviour. Stimulant medications address both reward deficiency and enhance motivation, as well as suppressing appetite. They have long been recognised to be effective for treating obesity. However, stimulants can be abused for their euphoric effect. They induce euphoria via the same neural pathway that underlies their therapeutic effect in obesity. For this reason they have generally not been endorsed for use in obesity. Among the stimulants, only phentermine (either alone or in combination with topiramate and bupropion (which has stimulant-like properties and is used in combination with naltrexone, are approved by the United States Food and Drug Administration (FDA for obesity, although dexamphetamine and methylpenidate are approved and widely used for treating attention deficit hyperactivity disorder (ADHD in adults and children. Experience gained over many years in the treatment of ADHD demonstrates that with careful dose titration, stimulants can be used safely. In obesity, improvement in mood and executive functioning could assist with the lifestyle changes necessary for weight control, acting synergistically with appetite suppression. The obesity crisis has reached the stage that strong consideration should be given to adequate utilisation of this effective and inexpensive class of drug.

Impact of behavioral control on the processing of nociceptive stimulation

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James W Grau

2012-08-01

Full Text Available How nociceptive signals are processed within the spinal cord, and whether these signals lead to behavioral signs of neuropathic pain, depends upon their relation to other events and behavior. Our work shows that these relations can have a lasting effect on spinal plasticity, inducing a form of learning that alters the effect of subsequent nociceptive stimuli. The capacity of lower spinal systems to adapt, in the absence of brain input, is examined in spinally transected rats that receive a nociceptive shock to the tibialis anterior muscle of one hind leg. If shock is delivered whenever the leg is extended (controllable stimulation, it induces an increase in flexion duration that minimizes net shock exposure. This learning is not observed in subjects that receive the same amount of shock independent of leg position (uncontrollable stimulation. These two forms of stimulation have a lasting, and divergent, effect on subsequent learning: Controllable stimulation enables learning whereas uncontrollable stimulation disables it (learning deficit. Uncontrollable stimulation also enhances mechanical reactivity (allodynia. We review evidence that training with controllable stimulation engages a BDNF-dependent process that can both prevent and reverse the consequences of uncontrollable shock. We relate these effects to changes in BDNF protein and TrkB signaling. Controllable stimulation is also shown to counter the effects of peripheral inflammation (from intradermal capsaicin. A model is proposed that assumes nociceptive input is gated at an early stage, within the dorsal horn. his gate is sensitive to current environmental relations (between proprioceptive and nociceptive input, allowing stimulation to be classified as controllable or uncontrollable. We further propose that the status of this gate is affected by past experience and that a history of uncontrollable stimulation will promote the development of neuropathic pain.

Impact of Behavioral Control on the Processing of Nociceptive Stimulation

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Grau, James W.; Huie, J. Russell; Garraway, Sandra M.; Hook, Michelle A.; Crown, Eric D.; Baumbauer, Kyle M.; Lee, Kuan H.; Hoy, Kevin C.; Ferguson, Adam R.

2012-01-01

How nociceptive signals are processed within the spinal cord, and whether these signals lead to behavioral signs of neuropathic pain, depends upon their relation to other events and behavior. Our work shows that these relations can have a lasting effect on spinal plasticity, inducing a form of learning that alters the effect of subsequent nociceptive stimuli. The capacity of lower spinal systems to adapt, in the absence of brain input, is examined in spinally transected rats that receive a nociceptive shock to the tibialis anterior muscle of one hind leg. If shock is delivered whenever the leg is extended (controllable stimulation), it induces an increase in flexion duration that minimizes net shock exposure. This learning is not observed in subjects that receive the same amount of shock independent of leg position (uncontrollable stimulation). These two forms of stimulation have a lasting, and divergent, effect on subsequent learning: controllable stimulation enables learning whereas uncontrollable stimulation disables it (learning deficit). Uncontrollable stimulation also enhances mechanical reactivity. We review evidence that training with controllable stimulation engages a brain-derived neurotrophic factor (BDNF)-dependent process that can both prevent and reverse the consequences of uncontrollable shock. We relate these effects to changes in BDNF protein and TrkB signaling. Controllable stimulation is also shown to counter the effects of peripheral inflammation (from intradermal capsaicin). A model is proposed that assumes nociceptive input is gated at an early sensory stage. This gate is sensitive to current environmental relations (between proprioceptive and nociceptive input), allowing stimulation to be classified as controllable or uncontrollable. We further propose that the status of this gate is affected by past experience and that a history of uncontrollable stimulation will promote the development of neuropathic pain. PMID:22934018

Claustral single cell reactions to tooth pulp stimulation in cats.

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Jastreboff, P; Sikora, M; Frydrychowski, A; Słoniewski, P

1983-01-01

Single unit activity in the central region of the claustrum, evoked by electrical stimulation of tooth pulp or paws was studied on cats under chloralose anesthesia. The majority of cells responded in similar manner to stimulation of tooth pulp or paws, but there were cells with clear preference to a given type of stimulation. Latencies of reactions evoked by tooth pulp stimulation were significantly shorter than those for limb stimulation. In the former case latencies as short as 8 rns were observed. It is postulated that the central region of the claustrum receives a projection from the tooth pulp, and that in those cases with very short latency the projection is direct and does not involve the cerebral cortex.

Low dose stimulation in foeniculum vulgare

International Nuclear Information System (INIS)

Jahagirdar, H.A.; Khalatkar, A.W.; Dnyansagar, V.R.

1974-01-01

Genetically pure seeds with a moisture content of 12.5% were irradiated in a 60 Co γ-source at a dose rate of 1.1 KR/min, the radiation dose varying between 2 and 14 KR. Four days after irradiation the seeds were sown into the open field. Stimulation was determined on the basis of a lot of parameters e.g. height. The results indicated a significant stimulation after 10 KR as far as seed yield is concerned. (MG) [de

The effect of Hegu acupoint stimulation in dental acupuncture analgesia

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Fransiskus Andrianto

2007-03-01

Full Text Available In daily life, dental treatments are often related with oral pain sensation which needs anesthesia procedures. Sometimes local anesthetics can not be used because patients have hypersensitive reaction or systemic diseases which may lead to complications. Stimulating acupoint, such as Hegu activates hypothalamus and pituitary gland to release endogenous opioid peptide substances that reduce pain sensitivity. The aim of the study was to determine Hegu acupoint stimulation effect on the pain sensitivity reduction in maxillary central incisor gingiva. The laboratory experimental research was conducted on 12 healthy male Wistar rats (3 months old, weights 150–200 grams. All rat samples received the same treatments and adapted within 1 month. The research was done in pre and post test control group design. 40-Volt electro-stimulation was done once on the maxillary central incisor gingiva prior to the bilateral Hegu acupoint stimulation, then followed by 3 times electro-stimulation with 3 minutes intervals. The pain scores were obtained based on the samples’ contraction in each electro-stimulation. The responses were categorized into 5 pain scores and statistically analyzed using Wilcoxon Test. The results showed that Hegu acupoint stimulation lowered the pain scores significantly (p < 0.05. Hegu acupoint stimulation could reduce the pain sensitivity in maxillary central incisor gingiva. Therefore, the use of acupuncture analgesia in dental pain management can be considered in the future.

Effect of anatomical variability in brain on transcranial magnetic stimulation treatment

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Syeda, F.; Magsood, H.; Lee, E. G.; El-Gendy, A. A.; Jiles, D. C.; Hadimani, R. L.

2017-05-01

Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

Luminescence optically stimulated: theory and applications

International Nuclear Information System (INIS)

Rivera M, T.; Azorin N, J.

2002-01-01

The thermally stimulated luminescence (Tl) has occupied an important place in the Solid state physics (FES) by the flexibility of the phenomena, mainly for its applications in the fields of Radiation Physics (FR) and Medical Physics (MF). The reason of this phenomena lies in the fact of the electrons release by the action of heat. Under that same reason, it can be used the action of another stimulant agent for releasing the trapped electrons in the metastable states (EM), this agent is the light which has the same effect that the heat, giving as result the production of light photons at using light in the visible spectra, of different wavelength that the excitation light. This phenomena is called Luminescence optically stimulated (LOE). The LOE has a great impact in the Solid State Physics (FES), dating and now in the use of the phenomena as a dosimetric method, alternate to the Tl, for its use in the ionizing and non-ionizing radiations fields. (Author)

Measured stimulated Raman gain in methane

International Nuclear Information System (INIS)

Lopert, R.B.

1983-01-01

This report is about the stimulated Raman effect in methane due to the nu 1 vibration. For various gas pressures between 150 torr and 30 atm, the Raman lineshape function was both experimentally measured and synthesized using a computer model. The stimulated Raman gain was measured by sending a pump laser beam provided by an argon-ion laser and a weak probe beam provided by a tunable dye laser through a cell of methane gas. The stimulated Raman effect caused some of the energy from the pump beam to be transferred to the probe beam. The intensity of the pump beam was low so the gain of the probe beam was on the order of parts per million. A two detector arrangement and a differential amplifier system that had a feedback loop to balance the detectors was constructed to measure the small gains. A detailed description of this detection system that was able to measure gains as small as 0.2 parts per million is provided

Are Participants Aware of the Type and Intensity of Transcranial Direct Current Stimulation?

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Matthew F Tang

Full Text Available Transcranial direct current stimulation (tDCS is commonly used to alter cortical excitability but no experimental study has yet determined whether human participants are able to distinguish between the different types (anodal, cathodal, and sham of stimulation. If they can then they are not blind to experimental conditions. We determined whether participants could identify different types of stimulation (anodal, cathodal, and sham and current strengths after experiencing the sensations of stimulation during current onset and offset (which are associated with the most intense sensations in Experiment 1 and also with a prolonged period of stimulation in Experiment 2. We first familiarized participants with anodal, cathodal, and sham stimulation at both 1 and 2 mA over either primary motor or visual cortex while their sensitivity to small changes in visual stimuli was assessed. The different stimulation types were then applied for a short (Experiment 1 or extended (Experiment 2 period with participants indicating the type and strength of the stimulation on the basis of the evoked sensations. Participants were able to identify the intensity of stimulation with shorter, but not longer periods, of stimulation at better than chance levels but identification of the different stimulation types was at chance levels. This result suggests that even after exposing participants to stimulation, and ensuring they are fully aware of the existence of a sham condition, they are unable to identify the type of stimulation from transient changes in stimulation intensity or from more prolonged stimulation. Thus participants are able to identify intensity of stimulation but not the type of stimulation.

Theory of feedback controlled brain stimulations for Parkinson's disease

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Sanzeni, A.; Celani, A.; Tiana, G.; Vergassola, M.

2016-01-01

Limb tremor and other debilitating symptoms caused by the neurodegenerative Parkinson's disease are currently treated by administering drugs and by fixed-frequency deep brain stimulation. The latter interferes directly with the brain dynamics by delivering electrical impulses to neurons in the subthalamic nucleus. While deep brain stimulation has shown therapeutic benefits in many instances, its mechanism is still unclear. Since its understanding could lead to improved protocols of stimulation and feedback control, we have studied a mathematical model of the many-body neural network dynamics controlling the dynamics of the basal ganglia. On the basis of the results obtained from the model, we propose a new procedure of active stimulation, that depends on the feedback of the network and that respects the constraints imposed by existing technology. We show by numerical simulations that the new protocol outperforms the standard ones for deep brain stimulation and we suggest future experiments that could further improve the feedback procedure.

β-Blockers, Cocaine, and the Unopposed α-Stimulation Phenomenon.

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Richards, John R; Hollander, Judd E; Ramoska, Edward A; Fareed, Fareed N; Sand, I Charles; Izquierdo Gómez, María Manuela; Lange, Richard A

2017-05-01

Cocaine abuse remains a significant worldwide health problem. Patients with cardiovascular toxicity from cocaine abuse frequently present to the emergency department for treatment. These patients may be tachycardic, hypertensive, agitated, and have chest pain. Several pharmacological options exist for treatment of cocaine-induced cardiovascular toxicity. For the past 3 decades, the phenomenon of unopposed α-stimulation after β-blocker use in cocaine-positive patients has been cited as an absolute contraindication, despite limited and inconsistent clinical evidence. In this review, the authors of the original studies, case reports, and systematic review in which unopposed α-stimulation was believed to be a factor investigate the pathophysiology, pharmacology, and published evidence behind the unopposed α-stimulation phenomenon. We also investigate other potential explanations for unopposed α-stimulation, including the unique and deleterious pharmacologic properties of cocaine in the absence of β-blockers. The safety and efficacy of the mixed β-/α-blockers labetalol and carvedilol are also discussed in relation to unopposed α-stimulation.

Enhancement of Phonological Memory Following Transcranial Magnetic Stimulation (TMS

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Matthew P. Kirschen

2006-01-01

Full Text Available Phonologically similar items (mell, rell, gell are more difficult to remember than dissimilar items (shen, floy, stap, likely because of mutual interference of the items in the phonological store. Low-frequency transcranial magnetic stimulation (TMS, guided by functional magnetic resonance imaging (fMRI was used to disrupt this phonological confusion by stimulation of the left inferior parietal (LIP lobule. Subjects received TMS or placebo stimulation while remembering sets of phonologically similar or dissimilar pseudo-words. Consistent with behavioral performance of patients with neurological damage, memory for phonologically similar, but not dissimilar, items was enhanced following TMS relative to placebo stimulation. Stimulation of a control region of the brain did not produce any changes in memory performance. These results provide new insights into how the brain processes verbal information by establishing the necessity of the inferior parietal region for optimal phonological storage. A mechanism is proposed for how TMS reduces phonological confusion and leads to facilitation of phonological memory.

MOTORIC STIMULATION RELATED TO FINE MOTORIC DEVELOPMENT ON CHILD

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Mira Triharini

2017-07-01

Full Text Available Introduction: Motor developmental stimulation is an activity undertaken to stimulate the children basic skills and so they can grow and develop optimally. Children who obtain a direct stimulus will grow faster than who get less stimulus. Mother’s behavior of stimulation is very important for children, it is considering as the basic needs of children and it must be fulfilled. Providing good stimulation could optimize fine motor development in children. The purpose of this study was to analyze mother’s behavior about motor stimulation with fine motor development in toddler age 4-5 years old. Method: Design have been  used in this study was cross sectional. Population were mothers and their toddler in Group A of Dharma Wanita Persatuan Driyorejo Gresik Preschool. Sample were 51 respondents recruited by using purposive sampling technique according to inclusion and exclusion criteria. The independent variable was mother’s behavior about motor stimulation whereas dependent variable was fine motor development in toddler. The data were collected using questionnaire and conducting observation on fine motor development based on Denver Development Screening Test (DDST. Data then analyzed using Spearman Rho (r test to find relation between mother’s behaviors about stimulation motor on their toddler fine motor development. Result: Results  of this study showed that there were correlations between mother’s knowledge and fine motor development in toddler (p=0.000, between mother’s attitude and fine motor development in toddler (p=0.000, and between mother’s actions and fine motor development in toddler (p=0.000. Analysis: In sort study found that there were relation between fine motor development and mother’s behavior. Discussion: Therefore mother’s behavior needed to be improved. Further research about stimulation motor and fine motor development aspects in toddler is required.

Mechanisms of magnetic stimulation of central nervous system neurons.

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Tamar Pashut

2011-03-01

Full Text Available Transcranial magnetic stimulation (TMS is a stimulation method in which a magnetic coil generates a magnetic field in an area of interest in the brain. This magnetic field induces an electric field that modulates neuronal activity. The spatial distribution of the induced electric field is determined by the geometry and location of the coil relative to the brain. Although TMS has been used for several decades, the biophysical basis underlying the stimulation of neurons in the central nervous system (CNS is still unknown. To address this problem we developed a numerical scheme enabling us to combine realistic magnetic stimulation (MS with compartmental modeling of neurons with arbitrary morphology. The induced electric field for each location in space was combined with standard compartmental modeling software to calculate the membrane current generated by the electromagnetic field for each segment of the neuron. In agreement with previous studies, the simulations suggested that peripheral axons were excited by the spatial gradients of the induced electric field. In both peripheral and central neurons, MS amplitude required for action potential generation was inversely proportional to the square of the diameter of the stimulated compartment. Due to the importance of the fiber's diameter, magnetic stimulation of CNS neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. Passive dendrites affect this process primarily as current sinks, not sources. The simulations predict that neurons with low current threshold are more susceptible to magnetic stimulation. Moreover, they suggest that MS does not directly trigger dendritic regenerative mechanisms. These insights into the mechanism of MS may be relevant for the design of multi-intensity TMS protocols, may facilitate the construction of magnetic stimulators, and may aid the interpretation of results of TMS of the CNS.

Mechanisms of magnetic stimulation of central nervous system neurons.

Science.gov (United States)

Pashut, Tamar; Wolfus, Shuki; Friedman, Alex; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

2011-03-01

Transcranial magnetic stimulation (TMS) is a stimulation method in which a magnetic coil generates a magnetic field in an area of interest in the brain. This magnetic field induces an electric field that modulates neuronal activity. The spatial distribution of the induced electric field is determined by the geometry and location of the coil relative to the brain. Although TMS has been used for several decades, the biophysical basis underlying the stimulation of neurons in the central nervous system (CNS) is still unknown. To address this problem we developed a numerical scheme enabling us to combine realistic magnetic stimulation (MS) with compartmental modeling of neurons with arbitrary morphology. The induced electric field for each location in space was combined with standard compartmental modeling software to calculate the membrane current generated by the electromagnetic field for each segment of the neuron. In agreement with previous studies, the simulations suggested that peripheral axons were excited by the spatial gradients of the induced electric field. In both peripheral and central neurons, MS amplitude required for action potential generation was inversely proportional to the square of the diameter of the stimulated compartment. Due to the importance of the fiber's diameter, magnetic stimulation of CNS neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. Passive dendrites affect this process primarily as current sinks, not sources. The simulations predict that neurons with low current threshold are more susceptible to magnetic stimulation. Moreover, they suggest that MS does not directly trigger dendritic regenerative mechanisms. These insights into the mechanism of MS may be relevant for the design of multi-intensity TMS protocols, may facilitate the construction of magnetic stimulators, and may aid the interpretation of results of TMS of the CNS.

Spectral characteristics of light sources for S-cone stimulation.

Science.gov (United States)

Schlegelmilch, F; Nolte, R; Schellhorn, K; Husar, P; Henning, G; Tornow, R P

2002-11-01