salvages purine deoxyribonucleosides: Topics by WorldWideScience.org

Transmural distribution of extracellular purines in isolated guinea pig heart.

The Lesch-Nyhan (LN) syndrome is a severe X chromosome-linked disease that results from a deficiency of the purine salvage enzyme hypoxanthine phosphoribosyltransferase (HPRT). The mutations leading to the disease are heterogeneous and frequently arise as de novo events. The authors have identified nucleotide alterations in 15 independently arising HPRT-deficiency cases by direct DNA sequencing of in vitro amplified HPRT cDNA. They also demonstrate that the direct DNA sequence analysis can be automated, further simplifying the detection of new mutations at this locus. The mutations include DNA base substitutions, small DNA deletions, a single DNA base insertion, and errors in RNA splicing. The application of these procedures allows DNA diagnosis and carrier identification by the direct detection of the mutant alleles within individual families affected by LN.

1989-03-01

Fluoride ion catalyzed alkylation of purines, pyrimidines, nucleosides and nucleotides using alky halides.

The purine adenosine appears to be involved in regulation of coronary vascular tone. Little is known concerning the levels and distribution of adenosine and related purines in the extracellular fluid...Full Text Available

1991-01-15

Clinical, virological and immunological responses in Danish HIV patients receiving raltegravir as part of a salvage regimen

Alkyl halides react rapidly with purines and pyrimidines in the presence of fluoride ion. Alkylation of thymidine leads to novel dimeric nucleoside derivatives bridged through N3. Alkylation of thymidine...Full Text Available

1979-04-01

DEFF Research Database (Denmark)

Raltegravir is the first integrase inhibitor approved for treatment of HIV-infected patients harboring multiresistant viruses.

2010-01-01

Bulk CS Overpack Salvage Drums United Nations (UN) ...

Science.gov (United States)

... SHEET. UNLESS OTHERWISE SPECIFIED, MATERIALS WILL BE MINIMUM SIZE lAW MIL-STD-2073-1. 18. TOLERANCES ...

1997-08-01

Purinergic receptors in the splanchnic circulation

Conformational transitions of alternating purine-pyrimidine DNAs in perchlorate ethanol solutions.

There is considerable evidence that purines are vasoactive molecules involved in the regulation of blood flow. Adenosine is a well known vasodilator that also acts as a modulator of the response to...Full Text Available

2008-09-01

Ophidian envenomation strategies and the role of purines.

Conformational transitions of poly(dA-dC).poly(dG-dT), poly(dA-dT).poly(dA-dT), and other alternating purine-pyrimidine DNAs were studied in aqueous ethanol solutions containing molar concentrations...Full Text Available

1995-11-01

Science.gov (United States)

Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in ...

2002-04-01

Strain differences in the responsiveness between Sprague-Dawley and Fischer rats to nephropathy induced by FYX-051, a xanthine oxidoreductase inhibitor

British Library Electronic Table of Contents (United Kingdom)

To determine a rat strain appropriate for carcinogenicity testing of FYX-051, a xanthine oxidoreductase inhibitor, we performed a 4-week oral toxicity study by administering 0.3, 1 and 3?mg/kg, and 1, 3 and 10?mg/kg of FYX-051 to male Sprague-Dawley (SD) and Fischer (F344) rats, respectively. Histopathology revealed that the degree of FYX-051-induced nephropathy was 3-fold stronger in SD rats than in F344 rats. Our previous study demonstrated that the key factor of species differences in FYX-051-induced nephropathy is purine metabolism. This observation led us to examine the involvement of purine metabolism in differences among two strains of rats. However, purine metabolism was proven not to be implicated as an important factor. Subsequently, other factors responsible for the strain diffe...

2006-01-01

Synthesis, Salvage, and Catabolism of Uridine Nucleotides in Boron-Deficient Squash Roots ¹

Vectors containing a prokaryotic dihydrofolate reductase gene transform Drosophila cells to methotrexate-resistance.

Previous work has provided evidence that plants may require boron to maintain adequate levels of pyrimidine nucleotides, suggesting that the state of boron deficiency may actually be one of pyrimidine...Full Text Available

1981-12-01

Transport of Purine and Pyrimidine Bases and Nucleosides from Endosperm to Cotyledons in Germinating Castor Bean Seedlings 1

Transformed Drosophila Kc cell lines, resistant to methotrexate, an inhibitor of de novo purine and pyrimidine synthesis, have been obtained by calcium phosphate transfection of plasmids containing...Full Text Available

1983-01-01

Antianxiety and antidepressant-like effects of AC-5216, a novel mitochondrial benzodiazepine receptor ligand

During germination and early growth of castor bean (Ricinus communis), all cellular constituents of the endosperm are eventually transferred to the growing embryo. The present results...Full Text Available

1983-10-01

Anticancer activity and cDNA microarray studies of a (RS)-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl]-6-chloro-9H-purine, and an acyclic (RS)-O,N-acetalic 6-chloro-7H-purine

We investigated the ability of N-benzyl-N-ethyl-2-(7,8-dihydro-7-methyl-8-oxo-2-phenyl-9H-purin-9-yl)acetamide...Full Text Available

2004-08-01

British Library Electronic Table of Contents (United Kingdom)

Completing a SAR study, a series of (RS)-6-substituted-7- or 9-(1,2,3,5-tetrahydro-4,1-benzoxazepine-3-yl)-7H or 9H-purines was previously prepared. The most potent antiproliferative agent against the MCF-7 adenocarcinoma cell line that belongs to the benzoxazepine O,N-acetalic family is (RS)-9-[1-(9H-fluorenyl-9-methoxycarbonyl)-1,2,3,5-tetrahydro-4,1-benzo xazepine-3-yl]-6-chloro-9H-purine (16, IC50 = 0.67 +- 0.18 mM), whilst (RS)-7-{2-(N-hydroxymethylphenyl)-2-nitrobenzenesulfonamido]-1-methoxye thyl}-6-chloro-7H-purine (37) shows the lowest IC50 value between the family of acyclic O,N-acetals (IC50 = 3.25 +- 0.23 mM). Moreover, 16 showed the better in vitro Therapeutic Index in breast cell lines (3.19), whilst 37 was found to be 3.69-fold more active against HT-29 human colon cancer ce...

2011-01-01

Benefits seen in liquid explosives

Nature of plant stimulators in the production of Acetobacter xylinum ({open_quotes}Tea fungas{close_quotes}) biofilm used in skin therapy

Explosives have been used in the removal of offshore wellhead devices for a number of years. In 1975, the first liquid explosives were run to remove wellheads and have proved to be a safe and reliable method of severing and salvaging the wellhead equipment from most depths of water. Methods of explosive wellhead removal and the areas of safety, reliability, and economics are discussed.

1981-09-01

Alterations in Adenylate Kinase Activity in Human PBMCs after In Vitro Exposure to Electromagnetic Field: Comparison between Extremely Low Frequency Electromagnetic Field (ELF) and Therapeutic Application of a Musically Modulated Electromagnetic Field (TAMMEF)

Caffeine and related xanthines were identified as potent stimulators for the bacterial cellulose production in A. xylinum. These compounds are present in several plants whose infusions are useful as culture-medium supplements for this acetobacterium. The proposed target for these native purine-like inhibitory substances is the novel diguanyl nucleotide phosphodiesterase(s) that participates in the bacterial cellulogenic complex.

1991-12-31

Megavoltage electron beam therapy in the treatment of basal and squamous cell carcinomata of the pinna

This study investigated the effects of electromagnetic fields on enzymes involved in purine metabolism in human peripheral blood mononuclear cells in vitro. Cells were obtained from 20 volunteers. We...Full Text Available

2009-01-01

Failure of the Tibial Insert in a Rotating Hinge Total Knee Arthroplasty

Forty-three patients with basal and squamous cell carcinomata arising on the pinna were treated radically using a 10 MeV electron beam. The technique and dosage are described and discussed. Primary cancer control with retention of the pinna was achieved in 34 patients. Salvage pinnectomy was performed in four patients for recurrence and one patient for radiation necrosis. Two patients with large primary tumours failed to resolve and died of their disease. The advantages for the patient of the policy of primary radical electron beam therapy are discussed.

1982-05-01

British Library Electronic Table of Contents (United Kingdom)

There has been a steady increase in the number of revision total knee arthroplasties being performed in the United States. Hinge knee prostheses are used predominantly in complex primary or revision arthroplasties, often as salvage procedures. Significant improvement of the articulation between the rotating hinge mechanism and tibial component has decreased the stresses that contributed to earlier failures in previous generation designs. Two cases of fracture of the tibial metal post in the rotating hinge of a revision total knee arthroplasty were evaluated and treated at our institution within a 1-month period. We present our experience with this construct failure and subsequent patient management.

2011-01-01

Solid-phase synthesis and pharmacological evaluation of novel nucleoside-tethered dinuclear platinum(II) complexes

British Library Electronic Table of Contents (United Kingdom)

Three novel inosine-based dinuclear platinum complexes have been synthesized via a solid-phase strategy. In these compounds, the metal is linked both to the N-7 of the purine nucleus and to the terminal amine group of a hexylamine side chain installed on N-1. Cis- or trans- diamine as well as ethylenediamine ligands are coordinated to platinum along with a chloride. The synthesised complexes were tested against four different human tumor cell lines. One of these complexes proved to be more cytotoxic than cisplatin against the MCF7 cancer cell line in a short-term exposure assay.

2011-01-01

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Total skin electron beam therapy followed by adjuvant psoralen/ultraviolet-a light in the management of patients with T1 and T2 cutaneous T-cell lymphoma (mycosis fungoides)

Surgical aspects of intestinal injury due to pelvic radiotherapy

Purpose: Patients with mycosis fungoides [cutaneous T-cell lymphoma (CTCL)] may benefit from adjuvant therapy after completing total skin electron beam therapy (TSEBT). We report the results for (T1(T2)) CTCL patients treated with adjuvant oral psoralen plus ultraviolet light (PUVA) with respect to overall survival (OS), disease-free survival (DFS), salvage of recurrence, and toxicity. Methods and Materials: Between 1974 and 1993, TSEBT was administered to a total of 213 patients with CTCL. Records were reviewed retrospectively, and a total of 114 patients were identified as having T1 or T2 disease. Radiotherapy was provided via a 6-MeV linac to a total of 36 Gy, 1 Gy/day, 4 days/week, for 9 weeks. Beginning in 1988, patients were offered adjuvant PUVA within 2 months of completing TSEBT. This was started at 0.5-2 J/m"2, 1-2 treatments/week, with a taper over 3-6 months. Therapy then continued once per month. There were 39 T1 and 75 T2 patients. Six T1 (15%) and ...

1997-07-15

Strain differences in the responsiveness between Sprague-Dawley and Fischer rats to nephropathy induced by FYX-051, a xanthine oxidoreductase inhibitor

Seventy-one patients with intestinal injury secondary to pelvic irradiation had predominantly large bowel lesions. Seventeen cases were treated conservatively and 54 came to surgery, 28 patients having more than one operation. Following this essentially salvage surgery there were more ileal than colonic anastomotic leaks. Thirty-four patients died during the follow-up period (2-12 years), 19 from recurrent malignancy, and nine as a result of continuing radiation effects. Seventy per cent of the patients who had a radiation fistula died as a result of malignancy. Of 42000 cases of pelvic malignancy treated by irradiation over the decade 1972-1982, surgical referrals for complications constituted 1.7%, with an overall radiation-related mortality of 0.2%. It is our opinion that colostomy alone has little part to play in this condition, and a policy based on excisional surgery is suggested.

1985-04-01

Constrained NBMPR analogue synthesis, pharmacophore mapping and 3D-QSAR modeling of equilibrative nucleoside transporter 1 (ENT1) inhibitory activity

To determine a rat strain appropriate for carcinogenicity testing of FYX-051, a xanthine oxidoreductase inhibitor, we performed a 4-week oral toxicity study by administering 0.3, 1 and 3 mg/kg, and 1, 3 and 10 mg/kg of FYX-051 to male Sprague-Dawley (SD) and Fischer (F344) rats, respectively. Histopathology revealed that the degree of FYX-051-induced nephropathy was 3-fold stronger in SD rats than in F344 rats. Our previous study demonstrated that the key factor of species differences in FYX-051-induced nephropathy is purine metabolism. This observation led us to examine the involvement of purine metabolism in differences among two strains of rats. However, purine metabolism was proven not to be implicated as an important factor. Subsequently, other factors responsible for the strain differences were examined. FYX-051-induced increases in plasma xanthine concentrations were higher in SD rats than in F344 rats, suggesting ...

2006-12-15

British Library Electronic Table of Contents (United Kingdom)

Conformationally constrained analogue synthesis was undertaken to aid in pharmacophore mapping and 3D-QSAR analysis of nitrobenzylmercaptopurine riboside (NBMPR) congeners as equilibriative nucleoside transporter 1 (ENT1) inhibitors. In our previous study [J. Med. Chem. 2003, 46, 831-837], novel regioisomeric nitro-1,2,3,4-tetrahydroisoquinoline conformationally constrained analogues of NBMPR were synthesized and evaluated as ENT1 ligands. 7-NO2-1,2,3,4-Tetrahydroisoquino-2-yl purine riboside was identified as the analogue with the nitro group in the best orientation at the NBMPR binding site of ENT1. In the present study, further conformational constraining was introduced by synthesizing 5prime-O,8-cyclo derivatives. The flow cytometrically determined binding affinities indicated that the...

2008-01-01

Diagnosis and treatment of Ewing's sarcoma

Data of spleen-scintiscanning after splenectomy

Ewing's sarcoma is a small round-cell tumor typically arising in the bones, rarely in soft tissues, of children and adolescents. Ewing's sarcoma has retained the most unfavorable prognosis of all primary musculoskeletal tumors. Prior to the use of multi-drug chemotherapy, long-term survival was less than 10%. The development of multi-disciplinary therapy with chemotherapy, irradiation, and surgery has increased current long-term survival rates in most clinical centers to greater than 50%. In addition, the preferred method of tumor resection has changed; limb salvage has nearly replaced amputation of the affected limb. Limb salvage procedures can be performed in place of amputation without compromising patient survival rates. Recent studies have revealed that the pathognomonic translocations involving the EWS gene on chromosome 22 and an ETS-type gene, which is most commonly the Fli1 gene on chromosome 11, are implicated in more than 95% of ...

2007-02-01

Identification of a nucleoside triphosphate binding site on calf thymus RNA polymerase II

In 65 adult rabbits of both sexes (2.5 to 6 kg) the following salvaging procedures were performed after simulated trauma: (1) Continuous suture line; (2) closure with fibrin sealant after temporary clamping; (3) hemisplenectomy with omental wrap; (4) suture fixation of fragments and slices of spleen tissue to the peritoneum; (5) suture fixation of spleen fragments to the omentum; (6) extraperitoneal subcutaneous transposition of spleen cubes. In addition, the likelihood of spontaneous splenosis was examined in a preliminary study involving 5 animals by introducing unattached spleen meal and fragments. Scanning was repeated 4 to 12 weeks postoperatively. The functional competence of minor parenchymal islands was also investigated with well counter measurements of organ and muscle tissue homogenates. Spontaneous splenosis after abdominal injuries was not found to be the rule. Salvaging procedures at the natural vascular hilus by sutures, fibrin ...

Deficiency of the housekeeping gene hypoxanthine-guanine phosphoribosyltransferase (HPRT) dysregulates neurogenesis.

A nucleoside triphosphate binding site on calf thymus RNA polymerase II was identified by using photoaffinity analogues of adenosine 5'-triphosphate and guanosine 5'-triphosphate. Both radiolabeled 8-azidoadenosine 5'-triphosphate (8-N3ATP) and radiolabeled 8-azidoguanosine 5'-triphosphate (8-N3GTP) bound to a single polypeptide of this enzyme. This polypeptide has a molecular mass of 37 kilodaltons and an isoelectric point of 5.4. Ultraviolet (UV) irradiation was necessary for photolabeling to occur. In addition, no labeling occurred when the probe was prephotolyzed or when the enzyme was inactivated. Furthermore, photolabeling of the enzyme could be decreased by preincubation with natural substrates. To provide evidence that the radiolabeled polypeptide forms a part of the domain of the nucleoside triphosphate binding site, experiments were performed using unlabeled 8-N3ATP. Although this unlabeled analogue was not a substrate for RNA polymerase ...

1986-01-14

Science.gov (United States)

Neuronal transcription factors play vital roles in the specification and development of neurons, including dopaminergic (DA) neurons. Mutations in the gene encoding the purine biosynthetic enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) cause the resulting intractable and largely untreatable neurological impairment of Lesch-Nyhan disease (LND). The disorder is associated with a defect in basal ganglia DA pathways. The mechanisms connecting the purine metabolic defect and the central nervous system (CNS) phenotype are poorly understood but have been presumed to reflect a developmental defect of DA neurons. We have examined the effect of HPRT deficiency on the differentiation of neurons in the well-established human (NT2) embryonic carcinoma neurogenesis model. We have used a retrovirus expressing a small hairpin RNA (shRNA) to knock down HPRT gene expression and have examined the expression of a number of transcription factors ...

2009-08-11

Tree and fruit traits of progenies from the cross between (Annona cherimola Mill.??A. squamosa L.)??A. reticulata L. and approaches for the introgression of valuable genes from A. reticulata L.

British Library Electronic Table of Contents (United Kingdom)

Annona reticulata L. possesses many traits desirable in other edible annonas, and hybridization is the simplest means to combine desirable features of related species. In this study, A. reticulata was hybridized with atemoya (A. cherimola Mill.??A. squamosa L.), and 250 trispecies hybrids were studied for 28 traits (12 tree traits and 16 fruit traits) with the objective of salvaging useful genes from the three edible annonas and determining the extent of variation in the progeny. The heterozygous nature of Annona spp. and simultaneous segregation of three distant genomes resulted in a tremendous heterogeneity in the progenies. The fitness of the progenies ranged from very vigorous to very weak, with a wide range of values for tree height (1.75?5.9?m), canopy spread (1.15?5.07?m) and trunk...

2010-01-01

Second malignancies after treatment for Ewing's sarcoma: a report of the CESS-studies

Results of electron beam therapy using intra-oral cone for carcinoma of the oral tongue

Purpose: During recent years, more intensified systemic and local treatment regimens have increased the 5-year survival figures in localized Ewing's sarcoma to more than 60%. There is, however, concern about the risk of second malignancies (SM) in long-term survivors. We have analyzed the second malignancies in patients treated in the German Ewing's Sarcoma Studies CESS 81 and CESS 86. Materials and Methods: From January 1981 through June 1991, 674 patients were registered in the two sequential multicentric Ewing's sarcoma trials CESS 81 (recruitment period 1981-1985) and CESS 86 (1986-1991). The systemic treatment in both studies consisted of a four-drug-regimen (VACA = vincristine, actinomycin D, cyclophosphamide, and adriamycin; or VAIA = vincristine, actinomycin D, ifosfamide, and adriamycin) and a total number of four courses, each lasting nine weeks, was recommended by the protocol. Local therapy in curative patients was either complete surgery (n = 162), surgery plus ...

1998-09-01

Radiation therapy for gastrointestinal lymphomas: indications and techniques

Retrospective analyses were performed to evaluate the therapeutic efficacy of intra-oral cone (IOC) radiation therapy for carcinoma of the oral tongue, especially about its faculty of local control and complications. Thirty-nine patients with squamous cell carcinoma of the oral tongue were treated with IOC radiation therapy alone or in combination with external irradiation. IOC radiation therapy was given not only for T1 and T2, but also for T3 tumors. Hypofractionation was used for IOC radiation therapy. The 2 year local control rates, including surgical salvage, for T1, T2, T3 and T4 were 100%, 73.3%, 40% and 0%, respectively. The 5 year actuarial survival rates for Stage I, II, III and IV were 100%, 65.3%, 35.4% and 0%, respectively. The incidences of radiation complications, i.e. soft tissue ulceration and osteoradionecrosis, were 42.9% and 2.9%, respectively. It is suggested that relatively high rate of soft tissue ulceration was due to hypofractionation. We ...

1992-07-01

Radiation therapy for Kasabach-Merritt syndrome. Analysis of unfavorable factors in 5 children

Gastrointestinal lymphomas are almost exclusively of a non Hodgkin's type. The Western form is characterized by a higher incidence of stomach location (50 %), a MALT type (mucosa associated lymphoid tissue) (40 %), a B-cell type (90 %), and a high grade (55 %). Chronic infection with Helicobacter pylori is an important risk factor. Mediterranean lymphomas form a particular clinical and pathological entity with diffuse involvement of the small bowel and are frequently being associated with a chronic malabsorption disorder. Eradication of Helicobacter pylori in early lymphomas, and the use of tetracyclines in early Mediterranean lymphomas, have been shown to induce durable remissions. For more advanced gastric lymphomas, treatment usually consists of anthracycline-based chemotherapy followed by involved field radiotherapy. Surgery is usually reserved for complications such as perforation or bleeding, or in some selected cases for salvage after failure of non-surgical ...

Demonstrating leadership inside and out : green building project trains employees, educates clients

During the past 10 years, five infants with Kasabach-Merritt syndrome (K-M) receiving radiation therapy were reported. We investigated whether radiation therapy for K-M was useful and what the unfavorable factors of K-M were. During the past 10 years, we have treated five infants with K-M. The syndrome occurred at ages ranging from birth to 4 months. The incidence of female to male ratio was 3:2. Among 5 cases, the site of hemangioma was as follows; shoulder, anterior chest wall, lower abdominal wall, face and neck and inguinal site. All 5 cases received medication to control the coagulopathy including prednisone and blood transfusion at first. Because the platelet count and the bleeding tendency did not improve in any case, these cases received radiation therapy. Total dose ranged from 5 to 10 Gy and fraction-size ranged from 0.5 to 1.75 Gy. Irradiation session was 2 or 3 times per week. In 5 cases, 4 cases showed cure of bleeding tendency and disappearance of tumor, and survived. In ...

1996-03-01

Radiation-induced damage to DNA; Les lesions radio-induites de l'ADN

This article described a full-scale green renovation project undertaken by a construction management firm in Newton, Massachusetts. Chapman Construction and Design began renovating its own office building in late 2007 and completed it in September 2008. The firm set out to achieve LEED Platinum certification from the United States Green Building Council. The project involved energy saving modifications to its mechanical systems; replacing plumbing fixtures with high efficiency alternatives to reduce water consumption by at least 40 per cent; installing skylights and additional windows to allow more natural light into the interior space; salvaging doors, lighting, metal studs and masonry whenever possible; and using sustainable products such as recyclable carpets, tiles and low-VOC paint. The main feature of the renovation was a new 47 kW (DC) photovoltaic (PV) solar power array installed on the rooftop. The PV array includes 208 panels and a SunPower SPR-225 system ...

2009-01-15

Extracellular ATP4- promotes cation fluxes in the J774 mouse macrophage cell line

This short survey focuses on the main radiation-induced base lesions that have been identified within cellular DNA. For this purpose, sensitive assays that are aimed at measuring a few modifications per 10{sup 7} normal bases were set-up. In that respect high performance liquid chromatography - tandem mass spectrometry (CLHP-MS/MS) was found to be able to single out the formation of 9 oxidized nucleosides and two modified nucleo-bases out of the 70 oxidative base lesions that have been identified in model systems. As a striking result, it was found that in the DNA of {gamma}-irradiated human monocytes, the formamide-pyrimidine derivative of guanine is produced in a higher yield than the ubiquitous 8-oxo-7,8-dihydro-guanine damage, both arising from the same radical precursor. However, relatively high doses of ionizing radiation (> 20 Gy) have to be applied in order to detect an increase in the level of the damage. This is due to the low efficiency for both low and high LET ...

2002-03-01

Direct photoaffinity labeling of gizzard myosin with ["3H]uridine diphosphate places Glu185 of the heavy chain at the active site

Extracellular ATP stimulates transmembrane ion fluxes in the mouse macrophage cell line J774. In the presence of Mg2+, nonhydrolyzable ATP analogs and other purine and pyrimidine nucleotides do not elicit this response, suggesting the presence of a specific receptor for ATP on the macrophage plasma membrane. One candidate for such a receptor is the ecto-ATPase expressed on these cells. We, therefore, investigated the role of this enzyme in ATP-induced /sup 86/Rb+ efflux in J774 cells. The ecto-ATPase had a broad nucleotide specificity and did not hydrolyze extracellular ATP in the absence of divalent cations. /sup 86/Rb+ efflux was not blocked by inhibition of the ecto-ATPase and did not require Ca2+ or Mg2+. In fact, ATP-stimulated /sup 86/Rb+ efflux was inhibited by Mg2+ and correlated with the availability of ATP4- in the medium. In the absence of divalent cations, the slowly hydrolyzable ATP analogs adenosine 5'-(beta, gamma-imido)triphosphate ...

1987-03-05

Alteration of nucleoside diphosphate binding specificity of E. coli elongation factor Tu (EF-Tu) by single amino acid substitution at position 138

The active site of chicken gizzard myosin was labeled by direct photoaffinity labeling with ["3H]UDP. ["3H] UDP was stably trapped at the active site by addition of vanadate (Vi) and Co"2"+. The extraordinary stability of the myosin.Co2+.[3H]UDP.Vi complex (t1/2 greater than 5 days at 0 degrees C) allowed it to be purified free of extraneous ["3H]UDP before irradiation began. Upon UV irradiation, greater than 60% of the trapped ["3H]UDP was photoincorporated into the active site. Only the 200-kDa heavy chain was labeled, confirming earlier results using ["3H]UTP. Extensive tryptic digestion of photolabeled myosin subfragment 1 followed by high performance liquid chromatography separations and removal of nucleotide phosphates by treatment with alkaline phosphatase allowed two labeled peptides to be isolated. Sequencing of the labeled peptides and radioactive counting showed that Glu185 was the residue labeled. Since UDP is a zero-length cross-linker, Glu185 is located at the ...

The role of interventional radiology in management of patients with end-stage renal disease

A single amino acid substitution (Asp #-># Asn) at position 138 of E. coli EF-Tu was induced in the tufA gene by an M13 phage oligonucleotide site-directed mutagenesis protocol. The mutated tufA gene was then subcloned in a plasmid vector and expressed in maxicells. The properties of ["3"5S]methionine labelled mutant and wild type EF-Tu's were compared by in vitro assays. Mutant and wild-type EF-Tu's bound EF-Ts with approximately equal affinities. The 138-Asn mutation greatly reduced the protein's affinity for GDP; however, this mutation dramatically increased the proteins affinity for XDP. The mutant protein forms a stable complex with phe-tRNA and XTP, which binds to ribosomes; whereas, it does not form a complex with phe-tRNA and GTP. These results suggest that in EF-Tu x NDP complexes amino acid residue 138 must interact with the substituent on C-2 of the purine ring. Thus in wild-type EF-Tu Asp-138 would H-bond to 2-NH_2 of GDP, and in the mutant EF-Tu ...

1987-06-07

Second malignancies after treatment for Ewing's sarcoma

The aim of the paper is to review the role of interventional radiology in the management of hemodialysis vascular access and complications in renal transplantation. The evaluation of patients with hemodialysis vascular access is complex. It includes the radiology/ultrasound (US) evaluation of the peripheral veins of the upper extremities with venous mapping and the evaluation of the central vein prior to the access placement and radiological detection and treatment of the stenosis and thrombosis in misfunctional dialysis fistulas. Preoperative screening enables the identification of a suitable vessel to create a hemodynamically-sound dialysis fistula. Clinical and radiological detection of the hemodynamically significant stenosis or occlusion demands fistulography and endovascular treatment. Endovascular prophylactic dilatation of stenosis greater than 50% with associated clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. The technical success ...

2003-05-01