Purification of tracer for somatomedin C radioimmunoassay by hydrophobic interaction chromatography

Energy Technology Data Exchange (ETDEWEB)

Baxter, R.C.; Brown, A.S.

1982-03-01

A tracer for use in the somatomedin C radiommunoassay by hydrophobic interaction chromatography was purified. Material showing greatest immunoreactivity binds to Octyl Sepharose CL-4B (Pharmacia) in a buffer mixture consisting of 130 mL of acetonitrile and 870 mL of 0.1 mol/L NH/sub 4/HCO/sub 3/, pH 7.8, but is eluted by increasing the acetonitrile content to 180 mL/L. As compared with tracer purified by binding to specific antiserum in liquid phase, precipitating the complex with second antibody, and then dissociating by gel chromatography at acid pH, this tracer shows equal immunoreactivity against specific somatomedin C antiserum. Either preparation allows excellent discrimination between extracts of normal, acromegalic, and hypopituitary plasma samples; thus either is suitable for use in the somatomedin C radioimmunoassay. Tracer purification by hydrophobic interaction chromatography is rapid and inexpensive. It may be useful in preparing highly immunoreactive tracers for other peptide radioimmunoassays.

Cross-validation of commercial enzyme-linked immunosorbent assay and radioimmunoassay for porcine C-peptide concentration measurements in non-human primate serum.

Science.gov (United States)

Gresch, Sarah C; Mutch, Lucas A; Janecek, Jody L; Hegstad-Davies, Rebecca L; Graham, Melanie L

2017-09-01

C-peptide concentration is widely used as a marker of insulin secretion and is especially relevant in evaluating islet graft function following transplantation, because its measurement is not confounded by the presence of exogenous insulin. To address the shortage of human islet donors, the use of porcine islets has been proposed as a possible solution and the stringent pig-to-non-human primate (NHP) model is often the most relevant for pre-clinical evaluation of the potential for diabetes reversal resulting from an islet xenograft. The Millipore radioimmunoassay (RIA) was exclusively used to measure porcine C-peptide (PCP) until 2013 when the assay was discontinued and subsequently a commercially available enzyme-linked immunosorbent assay (ELISA) from Mercodia has been widely adopted. Both assays have been used in pre-clinical trials evaluating the therapeutic potential of xenograft products in reversing diabetes in the pig-to-NHP model, to interpret data in a comparable way it may be useful to perform a harmonization of C-peptide measurements. We performed a method comparison by determining the PCP concentration in 620 serum samples collected from 20 diabetic cynomolgus macaques transplanted with adult porcine islets. All analyses were performed according to manufacturer instructions. With both assays, we demonstrated an acceptable detection limit, precision, and recovery. Linearity of the ELISA met acceptance criteria at all concentrations tested while linearity of the RIA only met acceptance criteria at five of the eight concentrations tested. The RIA had a detection limit of 0.16 ng/mL, and recovery ranged from 82% to 96% and met linearity acceptance criteria at 0.35 ng/mL and from 0.78 to 2.33 ng/mL. The ELISA had a detection limit of 0.03 ng/mL, and recovery ranged from 81% to 115% and met linearity acceptance criteria from 0.08 to 0.85 ng/mL. Both assays had intra-assay precision assay precision ELISA demonstrated a significant correlation with RIA (R

Release of leukotriene C4 from human polymorphonuclear leucocytes as determined by radioimmunoassay

International Nuclear Information System (INIS)

Aehringhaus, U.; Woelbling, R.H.; Peskar, B.M.; Peskar, B.A.; Koenig, W.; Patrono, C.

1982-01-01

Rabbits were immunized with a conjugate of leukotriene (LT)C 4 and bovine serum albumin prepared by coupling the single free amino group of the hapten to the protein using gluteraldehyde. Binding of [ 3 H]LTC 4 to the antibodies obtained is inhibited by 50% with 1.5 ng LTC 4 . The relative cross-section of LTD 4 is 16% and of LTC 4 -methyl ester 3.6%. The validity of the radioimmunoassay was demonstrated by comparison with bioassay using the isolated guinea pig ileum. Using the radioimmunoassay it could be shown that endogenous LTC 4 is released in a dose-dependent manner by human polymorphonuclear leucocytes stimulated with the divalent cation ionophore A23187. (Auth.)

Correlation of the secretion of insulin and C-peptide in cancer patients

Energy Technology Data Exchange (ETDEWEB)

Modnikov, O P; Lomtev, N G [Kirgizskij Nauchno-Issledovatel' skij Inst. Onkologii i Radiologii, Frunze (USSR)

1983-08-01

Insulin and C-peptide levels were studied with a radioimmunoassay in the peripheral blood serum of 44 patients with gastric and cervical cancer and 22 healthy persons. Hyperfunction of the pancreatic insular apparatus was shown in cancer patients which was expressed in a statistically significant increase in the C-peptide level. In gastric cancer patients hyperfunction of the insular apparatus was accompanied by hypoinsulinemia, and in cervical cancer patients by hormoinsulinemia. An analysis has shown that the ratio insulin/C-peptide in gastric and cervical cancer patients was about the same and significantly lower than the control. A conclusion has been made that in spite of difference in the initial insulin concentration, the same phenomenon - acceleration of the metabolic clearance of insulin - occurs in patients with cancer of the above sites. The C-peptide level decreased, the ratio insulin/C-peptide increased, i.e. hyperfunction of the insular apparatus disappeared and the metabolic clearance of insulin slowed down.

Correlation of the sectetion of insulin and C-peptide in cancer patients

International Nuclear Information System (INIS)

Modnikov, O.P.; Lomtev, N.G.

1983-01-01

Insulin and C-peptide levels were studied with a radioimmunoassay in the peripheral blood serum of 44 patients with gastric and cervical cancer and 22 healthy persons. Hyperfunction of the pancreatic insular apparatus was shown in cancer patients which was expressed in a statistically significant increase in the C-peptide level. In gastric cancer patients hyperfunction of the insular apparatus was accompanied by hypoinsulinemia, and in cervical cancer patients by hormoinsulinemia. An analysis has shown that the ratio insulin/C-peptide in gastric and cervical cancer patients was about the same and significantly lower than the control. A conclusion has been made that in spite of difference in the initial insulin concentration, the same phenomenon - acceleration of the metabolic clearance of insulin - occurs in patients with cancer of the above sites. The C-peptide level decreased, the ratio insulin/C-peptide increased, i.e. hyperfunction of the insular apparatus disappeared and the metabolic clearance of insulin slowed down

Radioimmunoassay of polypeptide hormones and enzymes

International Nuclear Information System (INIS)

Felber, J.P.

1974-01-01

General principles of radioimmunoassay are reviewed. Detailed procedures are reviewed for the following hormones: insulin, pituitary hormones, gonadotropins, parathyroid hormone, ACTH, glucagon, gastrin, and peptide hormones. Radioimmunoassay of enzymes is also discussed. (U.S.)

Serum and urine analysis of the aminoterminal procollagen peptide type III by radioimmunoassay with antibody Fab fragments.

Science.gov (United States)

Rohde, H; Langer, I; Krieg, T; Timpl, R

1983-09-01

A radioimmunoassay based on antibody Fab fragments was developed for the aminoterminal peptide Col 1-3 of bovine type III procollagen. This assay does not distinguish the intact aminopropeptide Col 1-3 from its globular fragment Col 1. Parallel inhibition profiles were observed with human serum and urine allowing the simultaneous quantitative determination of intact and fragmented antigens in these samples. Most of the material has a size similar to that of fragment Col 1 indicating that the aminopropeptide is degraded under physiologic conditions. The concentration of aminopeptide in normal sera was in the range 15-63 ng/ml. Daily excretion was found to be in the range 30-110 micrograms. More than 50% of patients with alcoholic hepatitis and liver cirrhosis showed elevated serum levels of aminopropeptide by the Fab assay. Elevated concentrations were detected more frequently with an antibody radioimmunoassay which measures mainly the intact form of the aminopropeptide. It is suggested that analysis of patients material by both assays could improve their diagnostic application.

Improvements in the automated radioimmunoassay for cAMP or cGMP

International Nuclear Information System (INIS)

Brooker, G.

1988-01-01

The work others in developing antibodies and the original radioimmunoassay for cyclic nucleotides provides the basis for these sensitive assays. The acetylation radioimmunoassay for cyclic nucleotides has enabled the measurement of cyclic AMP and cyclic GMP in very small biological samples. This is because accurate determinations can be made in samples containing less than 1 fmol of cyclic AMP or cyclic GMP. The Gamma-Flo automated radioimmunoassay system has been adapted to these assays such that cyclic nucleotides can be automatically measured at a rate of about 60 samples/hr. The Gamma-Flo instrument provides high-precision assays and eliminates human intervention in all steps of the radioimmunoassay. The automated assay has been in continuous operation in our laboratory over the last 10 years and this chapter summarizes the methodology and delineates improvements which have occurred over that time frame. Details for the preparation of the radioligands apply also to the manual acetylated radioimmunoassay for cyclic nucleotides

Human c-peptide immunoreactivity (CPR) in blood and urine - evaluation of a radioimmunoassay method and its clinical applications

Energy Technology Data Exchange (ETDEWEB)

Kuzuya, T; Matsuda, A; Saito, T; Yoshida, S

1976-01-01

A double-antibody radioimmunoassay method, using synthetic human connecting peptide as an immunizing antigen and standard, was evaluated for clinical assay of blood and urine samples. Normal fasting blood connecting peptide immunoreacivity (CPR) was 2.45 +- 0.96 ng/ml, increasing promptly after a 50 g oral glucose load, but somewhat slower than insulin. Molar concentration of CPR exceeded that of insulin. CPR responses to glucose were subnormal in diabetics, very low in juvenile-type cases, and often poor in patients on insulin treatment. Fasting CPR levels were elevated in patients on corticosteroid treatment and with uraemia. A patient with insulin 'auto-antibody' had high serum CPR. A considerable amount of CPR appeared in urine. Normal daily excretion of CPR was 1.52 +- 0.55 ..mu..g/kg or 55.1 +- 18.2 ng/mg creatinine. Urine CPR was very low in juvenile-type diabetics, and elevated in patients on corticosteroid treatment. The results confirm that blood and urine CPR are useful measures of the endocrine pancreatic function.

Radioimmunoassay for determination of the hormonal and immune states in patients aczema; psoriasis and neurodermatitis

International Nuclear Information System (INIS)

Baltabaev, T.S.

1989-01-01

The hormonal and immune status was investigated by a radioimmunoassay in 105 patiets with dermatosis (55 female and 50 male patients aged 15 to 80): 51 suffered frm ecsema, 41 -from psoriasis, and 13 - from neurodermatitis. Serum concentrations of T 3 , T 4 , TSH, insulin, trypsin, C-peptide, cortisol, and IgE were investigated. Disorders of the hormonal and immune status were noted in the examinees with relation to sez, type of disease, season, time-period and extent of disease

Two-site sandwich radioimmunoassay of human gamma interferon with monoclonal antibodies

Energy Technology Data Exchange (ETDEWEB)

Tanaka, E; Imai, M; Usuda, S; Tachibana, K; Okamoto, H; Ohike, Y; Nakamura, T; Miyakawa, Y; Mayumi, M [Jichi Medical School, Minamikawachi, Tochigi (Japan)

1985-03-18

Two monoclonal antibodies were raised against human gamma interferon (IFN-..gamma..) derived from E. coli harboring the recombinant cDNA for IFN-..gamma.., and one against a synthetic peptide representing its C-terminus amino acid sequence of 20 residues. The monoclonal antibody against the synthetic peptide reacted either with IFN-..gamma.. or the synthetic peptide. One monoclonal anti-IFN-..gamma.. did not react with the synthetic peptide, while the other showed a weak binding with the peptide. A 2-site '1-step' radioimmunoassay was developed. The assay was rapid with a sensitivity capable of detecting a few ng/ml of IFN-..gamma...

Characterization of an insulin-like growth factor-I/somatomedin-C radioimmunoassay specific for the C-peptide region

International Nuclear Information System (INIS)

Hintz, R.L.; Liu, F.; Seegan, G.

1982-01-01

Insulin-like growth factor-I (IGF-I) and somatomedin-C (SM-C) have been shown to be functionally identical by a number of criteria. We have synthesized the 12 amino acid C-peptide region of IGF-I (Gly-Tyr-Gly-Ser-Ser-Ser-Arg-Arg-Ala-Pro-Glu-Thr) and developed a RIA based on antibodies against this synthetic peptide. IGF-I and SM-C were indistinguishable in this RIA. No other peptides competed for this antiserum. The SM-C/IGF-I values of acid-chromatographed serum were strongly age dependent. The mean of children 1-5 yr old was 0.67 +/- 0.033 U/ml (mean +/- sD; n = 23), whereas the mean of children 12-17 yr old was 2.01 +/- 0.66 U/ml (n = 39) and the mean of 38 adults 26-85 yr old was 1.05 +/- 0.34. The SM-C/IGF-I values measured by this RIA were also growth hormone dependent. Thus, this region-specific RIA provides a clinically useful assessment of serum SM-C/IGF-I levels

Radioimmunoassay for the middle region of human parathyroid hormone: comparison of two radioiodinated synthetic peptides

International Nuclear Information System (INIS)

Sharp, M.E.; Marx, S.J.

1985-01-01

Two synthetic peptides were evaluated to develop radioligands for midregion-specific radioimmunoassay (RIA) of human parathyroid hormone (hPTH). Both radioligands were tested using three anti-PTH sera of proven clinical utility. While each of these midregion-directed antisera showed unique specificity, they all reacted with high affinity with both radioligands and none of them discriminated significantly between the two synthetic midregion peptides. Analysis of data on the relation of serum calcium and hPTH midregion immunoreactivity showed a useful separation of groups (all nonazotemic) with primary hyperparathyroidism, secondary hyperparathyroidism, primary hypoparathyroidism and secondary hypoparathyroidism. (Auth.)

Three-site sandwich radioimmunoassay with monoclonal antibodies for a sensitive determination of human alpha-fetoprotein

International Nuclear Information System (INIS)

Nomura, M.; Imai, M.; Takahashi, K.; Kumakura, T.; Tachibana, K.; Aoyagi, S.; Usuda, S.; Nakamura, T.; Miyakawa, Y.; Mayumi, M.

1983-01-01

Utilizing monoclonal antibodies against human alpha-fetoprotein, 3 distinct antigenic determinants were identified. These antigenic determinants, provisionally designated a, b and c, were arranged in such a manner that the binding of one determinant with the corresponding antibody did not inhibit, or only barely inhibited the binding of antibodies directed to the other 2 determinants. Monoclonal antibodies with 3 different specificities were, therefore, applied to develop a sandwich-type solid-phase radioimmunoassay of the antigen in which wells were coated with anti-a, and radiolabeled anti-b together with radiolabeled anti-c was employed to detect the bound antigen. The 3-site sandwich radioimmunoassay involving 3 different determinants gave a higher sensitivity than 2-site assays in which only anti-b or anti-c was employed as a radiolabeled reagent, because the radioactivity of the 2 labeled antibodies was added on the antigen bound to immobilized anti-a. (Auth.)

Radioimmunoassay of oxytocin

International Nuclear Information System (INIS)

Dawood, M.Y.; Raghavan, K.S.; Pociask, C.

1978-01-01

The evaluation of a radioimmunoassay of oxytocin is described. The method involved careful collection and transportation of blood at 4 0 C, acidification of the plasma, extraction with Fuller's earth and radioimmunoassay using antisera raised in rabbits immunized against oxytocin conjugated to bovine serum albumin and 125 I-labelled oxytocin. The antisera showed insignificant cross-reaction with a variety of small peptides including vasopressin and vasotocin. The limit of detection of the assay was 2.5 pg with intra-assay and interassay coefficients of variation of 7 to 15% and 12 to 18% respectively. Seventy-seven per cent (88 out of 116) of the pregnant women tested had detect-able maternal plasma oxytocin. Serial samples of maternal plasma showed a significant increase in oxytocin from the first to the second stage of labour and a significant decrease in the third stage. Oxytocin concentrations in the umbilical arterial plasma were significantly higher in patients in labour. The significance of these findings is discussed. (author)

Potential clinical usefulness of new glandular and circulating parathyroid peptides illuminated by sequence specific radioimmunoassay

International Nuclear Information System (INIS)

Lindall, A.W.; Cecchettin, M.

1981-01-01

It is now well known that human PTH peptides constitute a heterogeneous population of fragments of the eighty-four amino acid molecules. Over the years, considerable confusion has resulted from measurements made in both clinical and experimental settings with radioimmunoassays of either undefined or partially-defined specificity for a particular region of the intact molecule. The approach of the authors has been to make use of modern technology to synthesize peptide fragments that mimic portions of native molecules, and to use these fragments in RIA. A more detailed description of a portion of this work will appear in the Journal of Clinical Endocrinology and Metabolism. (Auth.)

Measurement of opioid peptides with combinations of reversed phase high performance liquid chromatography, radioimmunoassay, radioreceptorassay, and mass spectrometry

International Nuclear Information System (INIS)

Fridland, G.H.; Desiderio, D.M.

1987-01-01

As the first step, RP-HPLC gradient elution is performed of a Sep-Pak treated peptide-rich fraction from a tissue extract, and the eluent is monitored by a variety of post-HPLC detectors. In an effort to maximize the structural information that can be obtained from the analysis, UV provides the analog absorption trace; receptorassay analysis (RRA) data of all fractions that are collected are used to construct the profile of opioid-receptoractive peptides; radioimmunoassay (RIA) of selected HPLC fractions at retention times corresponding to the retention time of standards, or in some special cases of all 90-fractions, provides immunoreactivity information; and fast atom bombardment mass spectrometry (FAB-MS) in two modes - corroboration of the (M + H) + of the expected peptide, or MS/MS to monitor an amino acid sequence-determining fragment ion unique to that peptide in the selected ion monitoring (SIM) mode - provides structural information. As a demonstration of the level of quantification sensitivity that can be attained by these novel MS methods, FAB-MS-MS-SIM of solutions of synthetic leucine enkephalin was sensitive to the 70 femtomole level. This paper discusses RIA versus RRA data, and recent MS measurements of peptides in human tissues. 4 references, 1 figure

Problems in radioimmunoassay of human lutropin with commercially available regents

International Nuclear Information System (INIS)

Hammond, J.E.; Phillips, J.C.; Straight, C.B.; Hammond, M.G.

1980-01-01

To evaluate five commercially available reagent sets supplied for the radioimmunoassay of lutropin, we determined whether there was parallelism between the curve given by dilutions of the standards supplied by the manufacturers, by dilutions of a serum pool, and by dilutions of a standard preparation from human pituitaries, LER-907. These studies demonstrated significant analytical problems with three of the five sets. We conclude that each user should carefully evaluate all commercially available radioimmunoassays for lutropin (and, by inference, for other peptide hormones) before use

Application of radioimmunoassay in food industry

International Nuclear Information System (INIS)

Rauch, P.; Fukal, L.; Kas, J.

1983-01-01

Radioimmunoassay can be used in evaluating the quality and wholesomeness of food. The method is advantageous for its speed, specificity, high sensitivity, relative ease of performance, and the possibility of performing a great number of parallel determinations using automation and computer evaluation. It can be used in determining macromolecules of proteins and enzymes. The determination of papain in beer is shown by way of example. Other possibilities of the method include: the determination of microbial toxins of the peptide nature, vitamins, hormones, antibiotics, pesticides and their residues, alkaloids, and carcinogenic materials. (M.D.)

Studies on radioimmunoassay of peptide hormone using polyethyleneglycol. I. Insulin

Energy Technology Data Exchange (ETDEWEB)

Kihara, A; Kikuchi, A; Yaegashi, T; Ohhara, H [Sapporo Medical Coll. (Japan)

1975-06-01

Radioimmunoassay (RIA) of insulin using polyethyleneglycol (PEG) was examined for measurement conditions such as the concentration, reaction time, temperature, and amount of serum to be added in order to allow uniform separations of free insulin and bound insulin. The standard curve of the present method was in good agreement with that of the two antibody method, and the two methods showed a highly significant correlation (r=0.98, p<0.001). The reproducibility showed only the fluctuations ranging from 0.9 to 4.9%, and the recovery rate was between 70 and 100%. Since the insulin RIA by PEG is convenient and economical and yields more stable results than those obtained by the two antibody method, it is possible to use it for RIA of other peptide hormones such as glucagon.

Comparative study of radioimmunoassay dates

International Nuclear Information System (INIS)

Venegas Sanchez, Ruth.

1986-01-01

The radioimmunoassay is frequently used in clinical chemistry for the concentration determination of several substances like hormones as thyrotropine and thyroxine. In this experiment the dates of tyroxine radioimmunoassay are processed by three methods: a) like the recommendation of the IAEA, b) Dr. G. Chase method, c) according to the provider. The best method was Dr. Chase's. (author)

Connecting peptide (c-peptide) and the duration of diabetes mellitus ...

African Journals Online (AJOL)

Objective: C-peptide is derived from proinsulin and it is secreted in equimolar concentration with insulin. Plasma C-peptide is more stable than insulin and it provides an indirect measure of insulin secretory reserve and beta cell function. To determine relationship between C-peptide and duration of diabetes mellitus, age, ...

Determination of triiodothyronine in serum by enzyme- and radioimmunoassay

International Nuclear Information System (INIS)

Oellerich, M.; Haindl, H.; Medizinische Hochschule Hannover

1981-01-01

An evaluation of a heterogeneous enzyme immunoassay for determination of triiodothyronine in serum (Enzymun-Test T 3 , Boehringer Mannheim) is presented. The enzyme immunoassay was compared with the laboratory routine radioimmunoassay. The precision of both assays was satisfactory at triiodothyronine concentrations between 1.0 and 8.0 nmol/l (coefficients of variation from day to day 3 from 96-104% and with the radioimmunoassay from 88-111%. A comparison of the results obtained by Enzymun-Test T 3 and the radioimmunoassay in a series of 103 patients showed a good correlation between both methods. L-thyroxine did not cause a relevant cross-reaction in the enzyme immunoassay. About 20 unknown samples can be analyzed in triplicate by Enzymun-Test T 3 within 260 minutes. (orig.) [de

Studies on a novel peptide isolated and purified from rat insulinoma tissue

Energy Technology Data Exchange (ETDEWEB)

Al-Akhras, G N

1987-01-01

Rat insulinoma peptide (RIP) which appears to be either a fragment of, or an altered rat C-peptide was isolated and purified by dialysis. The purity of this peptide was investigated using polyacrylamide gel electrophoresis with sodium dodecyl sulfate, isoelectric focusing, and high performance liquid chromatography. RIP may contain two peptides similar to each other but differing in their isoelectric points. The molecular weight of RIP was found to be 1982 daltons by fast atoms bombardment mass spectrometry giving a chain length of approximately 22 amino acid residues. From information obtained using radioimmunoassay employing antiserum R901, RIP appears to share a common C-terminus with rat C-peptide. A radioimmunoassay for RIP was developed using the purified RIP as immunogen and for standards and tracers. An indirect enzyme linked immunosorbent assay (ELISA) for rat insulinoma peptide was developed using purified RIP for immunogen and semi-purified RIP as a standard.

Measurements of urinary kinins by HPLC-radioimmunoassay

International Nuclear Information System (INIS)

Fejes-Toth, G.; Naray-Fejes-Toth, A.; Froelich, J.C.

1984-01-01

In this paper the authors describe a method for the individual determination of urinary kinins. Extraction from the urine is performed on an Amberlite CG-50 column and kinins are eluted with formic acid. The samples are further purified and kinins are separated by reversed phase HPLC. Bradykinin and lysylbradykinin are quantified by a sensitive radioimmunoassay capable of detecting 0.1 fmol of either peptide. Procedural losses are monitored by measuring the recovery of [ 3 H]bradykinin and [ 3 H]lysylbradykinin. Simple methods for labeling of bradykinin and lysylbradykinin with tritium are also presented. Recoveries of [ 3 H]bradykinin and [ 3 H]lysylbradykinin from biological material ranged between 77 and 91%. The combination of HPLC with radioimmunoassay makes it possible to determine kinin concentrations of biological samples with a higher sensitivity and greater specificity than previous methods. (Auth.)

Evalation of a radioimmunoassay for somatomedin-C/insulin-like growth factor I (Sm-C/IGF-I) in human plasma

International Nuclear Information System (INIS)

Giannella-Neto, D.; Cavaleiro, A.M.; Wajchenberg, B.L.; Sadoyama, R.; Spencer, E.M.

1990-01-01

In the present report the authors describe the development of a very sensitive radioimmunoassay for the quantitativew determination of human somatomedin-C/insulin-like growth factor I in plasma samples extracted by an acid-ethanol procedure. (RB). 22 refs.; 1 fig.; 1 tab

Radioimmunoassay for chicken avidin. Comparison with a (/sup 14/C)biotin-binding method

Energy Technology Data Exchange (ETDEWEB)

Kulomaa, M S; Elo, H A; Tuohimaa, P J [Tampere Univ. of Tech. (Finland)

1978-11-01

A double-antibody solid-phase radioimmunoassay for chicken avidin is reported. Avidin was labelled with /sup 125/I by the chloramine-T method. The bound and free avidin were separated with a second antibody bound to a solid matrix. In the logit-log scale the standard curve was linear from 1-2 to 100-200ng of avidin/ml. Cross-reaction of ovalbumin was less than 0.015%. Saturation of biotin-binding sites of avidin with an excess of biotin decreased radioimmunoassay values by about 15%. Recovery studies indicated that avidin can be assayed from all chicken tissues studied with radioimmunoassay, whereas the (/sup 14/C)biotin/bentonite method gave poor recoveries for avidin in the liver and kidney. Radioimmunoassay and the (/sup 14/C)biotin/bentonite method gave similar concentrations for oviduct avidin.

Comparison of commercially available radioimmunoassays for the determination of bile acids in serum

Energy Technology Data Exchange (ETDEWEB)

Wildgrube, H.J.; Schiller, W.; Winkler, M.; Weber, J.; Campana, H.; Mauritz, G.

1982-05-01

Three commercially available radioimmunoassays for the determination of bile acids in serum were evaluated with respect to specificity and precision. The SLCG-radioimmunoassay (Abbott) measures only sulphated glycolithocholic acid, the CG-radioimmunoassay (Abbott) measures chiefly cholic acid conjugates, and the CBA-radioimmunoassay (Becton-Dickinson) measures all conjugated bile acids, with an over-response to taurine metabolites. With respect to cross reactions, the performances of the CG-and the CBA-radioimmunoassays differed significantly from those stated by the manufacturers, the former showing a 32% response to taurocholic acid, the latter responding only 118% to taurochenodeoxycholic acid. At physiological concentrations of albumin + globulin, the recovery of defined cholanic acids was 85-101%. Good reproducibility was shown by the CG-radioimmunoassay in the range 0.5-10.9 ..mu..mol/l, by the CBA-radioimmunoassay in the range 1.0-25.0 ..mu..mol/l, and by the SLCG-radioimmunoassay in the range 0.5-3.0 ..mu..mol/l. There were no important differences in the inter- and intra-assay precision of the three methods.

Discordant expression of pro-B-type and pro-C-type natriuretic peptide in newborn infants of mothers with type 1 diabetes

DEFF Research Database (Denmark)

Nybo, Mads; Nielsen, Lars Bo; Nielsen, Søren Junge

2007-01-01

CNP-derived peptides in newborn infants. METHODS: Plasma concentrations of proCNP-derived peptides were measured in umbilical cord plasma and human placental tissue extracts using sequence-specific radioimmunoassays raised against N-terminal and C-terminal proCNP regions, respectively. RESULTS: The median pro...... in umbilical cord plasma compared to adult plasma (4.6 vs. 1.1), which parallels our earlier findings for proBNP and BNP peptides. CONCLUSIONS: There is a discordant expression of CNP and BNP peptides in newborn infants of mothers with diabetes. Moreover, fetal metabolism of proCNP and CNP appears to differ...

Determination of digoxin by enzyme immunoassay and radioimmunoassay

International Nuclear Information System (INIS)

Mueller, H.; Braeuer, H.; Foerster, G.; Reinhardt, M.

1978-01-01

The results of parallel determinations of digoxin in the sera of non selected patients (n=104) by enzyme immunoassay (EMIT.EIA) and radioimmunoassay (J-125 labeled RIA) were compared with each other. The determinations revealed considerably different concentrations; the values determined by EIA were statistical lower (for EIA 1,09+'0,99ng/ml, for RIA 1,34+'1,01ng/ml, p [de

Changes of serum leptin and c-peptide level in children with type 1 diabetic mellitus

International Nuclear Information System (INIS)

Du Tongxin; Wang Zizheng; Sun Junjiang; Wang Shukui; Qi Shaokang

2001-01-01

To deplore the relationship between leptin and c-peptide in children with type 1 diabetic mellitus (DM). The levels of serum leptin and c-peptide (C-P) in 65 type 1 DM children (including 31 before and after insulin treatment) and 30 normal controls were measured by radioimmunoassay (RIA). The results found that there was significant differences (P < 0.01) in leptin and C-P between DM children and normal controls, also in 31 DM children before and after treatment. It showed a positive correlation between leptin and C-P. The changes of the leptin/C-P ratio in DM children compared with normal controls and that before and after treatment were also significantly different. It suggested that leptin may have close relationship in the development, progress and the occurrence of complications in children with DM and also provide a new clue for their diagnosis treatment and complication occurrence

Levels of human and rat hypothalamic growth hormone-releasing factor as determined by specific radioimmunoassay systems

International Nuclear Information System (INIS)

Audhya, T.; Manzione, M.M.; Nakane, T.; Kanie, N.; Passarelli, J.; Russo, M.; Hollander, C.S.

1985-01-01

Polyclonal antibodies to synthetic human pancreatic growth hormone-releasing factor [hpGRF(1-44)NH 2 ] and rat hypothalamic growth hormone-releasing factor [rhGRF(1-43)OH] were produced in rabbits. A subsequent booster injection by the conventional intramuscular route resulted in high-titer antibodies, which at a 1:20,000 dilution were used to develop highly sensitive and specific radioimmunoassays for these peptides. The antibody to hpGRF(1-44)NH 2 is directed against the COOH-terminal region of the molecule, as shown by its cross reactivity with various hpGRF analogues. Serial dilutions of human and rat hypothalamic extracts demonstrated parallelism with the corresponding species-specific standard and 125 I-labeled tracer. There was no cross reactivity with other neuropeptides, gastrointestinal peptides, or hypothalamic extracts of other species. Age-related changes in hypothalamic GRF content were present in rats, with a gradual increase from 2 to 16 weeks and a correlation between increasing body weight and GRF content. These radioimmunoassays will serve as important tools for understanding the regulation of growth hormone secretion in both human and rat

Radioimmunoassay for detection of VP1 specific neutralizing antibodies of foot and mouse disease virus

International Nuclear Information System (INIS)

Patzer, E.J.; Jackson, M.L.; Moore, D.M.

1985-01-01

A solid-phase radioimmunoassay was developed for the detection of antibodies against a specific region of the VP1 protein of the A24 and O1 serotypes of foot and mouth disease virus. The antibody titers from the radioimmunoassay showed a positive correlation with neutralizing antibody titers determined by a mouse protection assay. The specificity of the assay resides in the peptide used as antigen. The assay is rapid, reproducible and does not require the use of whole virions. (orig.)

Importance of radioimmunoassay of insulin secretion disorder as atherogenic factor

Energy Technology Data Exchange (ETDEWEB)

Knyazev, Yu A; Bespalova, V A; Vakhrusheva, L L; Kirbasova, N P; Severtseva, V V

1984-11-01

Using a radioimmunoassay a C-peptide levei was revealed in children, pregnant and lying-in women as well as in patients with insulin-dependent diabetes mellitus. After breakfast and insulin administration wich curative purposes the IRI concentration in children increased whereas the C-peptide level changed insignificantly. Changes of the insulin secretion were more noticeable in severe diabetes mejlitus with vascular complications and in disease decompensation. The atherogenic nature of the lipid metaboiism (an increase in the cholesterol, triglyceride and ..beta..-lipoprotein levels), changes in the liver and tendency to vascular involvement are results of insulin effect inadequacy. Such metabolic derangements in pregnant women create unfavorable conditions for the development of fetus and may lead to early atherogenic processes.

Measurement of insulin and C-peptide excitatory test levels in gestational diabetes mellitus

International Nuclear Information System (INIS)

Du Tongxin; Wang Zizheng

2001-01-01

To investigate the function of islet β cells in patients with gestational diabetes mellitus (GDM), serum insulin and C-peptide (C-P) excitatory test levels were measured dynamically by radioimmunoassay in 41 patients with GDM and 30 normal pregnant controls. The results showed that there were significant difference in insulin and C-peptide excitatory test levels between normal pregnancy for 32-40 weeks and patients with GDM (P < 0.001). The secretory peak of insulin occurred at 60 min in normal pregnancy, while at 120 min in patients with GDM, and the recovery postponed in patients with GDM. The peak time for C-P was just as same as that of insulin, but the peak error for C-P between normal pregnant controls and patients with GDM was more larger than that for insulin and it recovered more slowly. It suggested that majority of islet β cells in patients with GDM were good enough for response to islet resistance factors and big stress from pregnancy, and also suggested a relation between pregnancy and islet β cells function

Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity

International Nuclear Information System (INIS)

Nascimento, Martha do

1996-01-01

The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of β cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author)

Direct salivary cortisol radio-immunoassay determination. Clinical applications

International Nuclear Information System (INIS)

Simon, C.; Cherfan, J.; Kurtz, F.; Vignon, F.; Schlienger, J.L.; Chabrier, G.

1987-01-01

Salivary cortisol levels reflect the biologically active free fraction of blood cortisol. The authors describe the results obtained with the aim of a radio-immunoassay commercial serum cortisol kit, without prealable extraction in different physiological and pathological situations. Salivary cortisol determination appears performant both in nycthemeral studies and in stimulation or freination tests [fr

Comparative studies on the determination of alphafetoprotein by enzyme immunoassay and by radioimmunoassay

International Nuclear Information System (INIS)

Haller, G.; Linneke, P.; Voss, P.; Jeske, W.

1987-01-01

Alphafetoprotein (AFP) was determined in serum of pregnant women in the tenth till sixteenth week of pregnancy by means of two enzyme immunoassays (Enzymun-Test AFP, Boehringer Mannheim, FRG and AFP EIA 'Dessau' 1000, Research Institute for Vaccine Dessau, GDR) and a radioimmunoassay (Radioimmunoassay Kit, AFP-PR, CIS, France). Parallel determinations in sera of 438 patients, who had come to surveillance for the first consultation were estimated. A comparison between the methods showed a good correlation. (author)

Production of peptide antisera specific for mouse and rat proinsulin C-peptide 2

DEFF Research Database (Denmark)

Blume, N; Madsen, O D; Kofod, Hans

1990-01-01

for antibody binding to the immunizing antigen. Antisera to C-peptide 2, stained islet beta-cells on mouse and rat, but not monkey pancreas sections in immunocytochemical analysis. Preabsorption to the synthetic C-peptide 2, but not the synthetic mouse and rat C-peptide 1 abolished staining. In conclusion we......Mice and rats have two functional non-allelic insulin genes. By using a synthetic peptide representing a common sequence in mouse and rat C-peptide 2 as antigen, we have produced rabbit antisera specific for an epitope which is not present in mouse or rat C-peptide 1. Long-term immunization did...... not seem to increase the end point titre as tested in direct ELISA. The specificity of the antiserum was determined by competitive ELISA and histochemistry on pancreas sections. Only the synthetic C-peptide 2, but not the homologous synthetic C-peptide 1 from mouse and rat competed efficiently in ELISA...

Radioimmunoassay for antigliadin-antibodies using 14C-labelled gliadin

International Nuclear Information System (INIS)

Menzel, J.

1977-01-01

A sensitive radioimmunoassay for antibodies to gliadin has been developed. Gliadin from wheat gluten was labelled with [1- 14 C]acetic anhydride to a specific activity of 2.6 x 10 6 dpm/mg. Immunological evidence is presented that the antigen was not essentially altered by the labelling procedure. Experimentally-induced antigliadin antibodies or sera of patients with coeliac disease (CD) were reacted with labelled gliadin and the immune complexes formed precipitated by antiglobulin. Precipitating antibodies were determined by incubating CD sera with labelled gliadin and measuring the radioacticity in precipitates formed without the addition of second antibody. Comparison with other methods for the detection of antigliadin antibodies, including immunoelectrophoresis, immunodiffusion and passive hemagglutination indicated that total and precipitating antibodies were determined only by RIA. The assay also provides information on the immunoglobulin class of antigliadin-antibodies present in sera of patients with coeliac disease

 Pleiotropic action of proinsulin C-peptid

Directory of Open Access Journals (Sweden)

Michał Usarek

2012-03-01

Full Text Available  Proinsulin C-peptide, released in equimolar amounts with insulin by pancreatic β cells, since its discovery in 1967 has been thought to be devoid of biological functions apart from correct insulin processing and formation of disulfide bonds between A and B chains. However, in the last two decades research has brought a substantial amount of data indicating a crucial role of C-peptide in regulating various processes in different types of cells and organs. C-peptide acts presumably via either G-protein-coupled receptor or directly inside the cell, after being internalized. However, a receptor binding this peptide has not been identified yet. This peptide ameliorates pathological changes induced by type 1 diabetes mellitus, including glomerular hyperfiltration, vessel endothelium inflammation and neuron demyelinization. In diabetic patients and diabetic animal models, C-peptide substitution in physiological doses improves the functional and structural properties of peripheral neurons and protects against hyperglycemia-induced apoptosis, promoting neuronal development, regeneration and cell survival. Moreover, it affects glycogen synthesis in skeletal muscles. In vitro C-peptide promotes disaggregation of insulin oligomers, thus enhancing its bioavailability and effects on metabolism. There are controversies concerning the biological action of C-peptide, particularly with respect to its effect on Na /K -ATPase activity. Surprisingly, the excess of circulating peptide associated with diabetes type 2 contributes to atherosclerosis development. In view of these observations, long-term, large-scale clinical investigations using C-peptide physiological doses need to be conducted in order to determine safety and health outcomes of long-term administration of C-peptide to diabetic patients.

Identities of P2 and P3 Residues of H-2Kb-Bound Peptides Determine Mouse Ly49C Recognition.

Directory of Open Access Journals (Sweden)

Elsa A Marquez

Full Text Available Ly49 receptors can be peptide selective in their recognition of MHC-I-peptide complexes, affording them a level of discrimination beyond detecting the presence or absence of specific MHC-I allele products. Despite this ability, little is understood regarding the properties that enable some peptides, when bound to MHC-I molecules, to support Ly49 recognition, but not others. Using RMA-S target cells expressing MHC-I molecules loaded with individual peptides and effector cells expressing the ectodomain of the inhibitory Ly49C receptor, we found that two adjacent amino acid residues, P2 and P3, both buried in the peptide binding groove of H-2Kb, determine mouse Ly49C specificity. If both are aliphatic residues, this is supportive. Whereas, small amino acids at P2 and aromatic amino acids at the P3 auxiliary anchor residue are detrimental to Ly49C recognition. These results resemble those with a rat Ly49 where the identity of a peptide anchor residue determines recognition, suggesting that dependence on specific peptide residues buried in the MHC-I peptide-binding groove may be fundamental to Ly49 peptide selectivity and recognition.

Insulin C-peptide test

Science.gov (United States)

C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin the body produces and insulin someone injects ...

A radioimmunoassay for chicken avidin

International Nuclear Information System (INIS)

Kulomaa, M.S.; Elo, H.A.; Tuohimaa, P.J.

1978-01-01

A double-antibody solid-phase radioimmunoassay for chicken avidin is reported. Avidin was labelled with 125 I by the chloramine-T method. The bound and free avidin were separated with a second antibody bound to a solid matrix. In the logit-log scale the standard curve was linear from 1-2 to 100-200ng of avidin/ml. Cross-reaction of ovalbumin was less than 0.015%. Saturation of biotin-binding sites of avidin with an excess of biotin decreased radioimmunoassay values by about 15%. Recovery studies indicated that avidin can be assayed from all chicken tissues studied with radioimmunoassay, whereas the [ 14 C]biotin/bentonite method gave poor recoveries for avidin in the liver and kidney. Radioimmunoassay and the [ 14 C]biotin/bentonite method gave similar concentrations for oviduct avidin. (author)

Fasting plasma C-peptide, glucagon stimulated plasma C-peptide, and urinary C-peptide in relation to clinical type of diabetes

DEFF Research Database (Denmark)

Gjessing, H J; Matzen, L E; Faber, O K

1989-01-01

with a fasting plasma C-peptide value less than 0.20 nmol/l, a glucagon stimulated plasma C-peptide value less than 0.32 nmol/l, and a urinary C-peptide value less than 3.1 nmol/l, or less than 0.54 nmol/mmol creatinine/24 h, or less than 5.4 nmol/24 h mainly were Type 1 diabetic patients; while patients with C...

Radioimmunoassay methods for the determination of L-triiodo-thyronine and thyroxine

International Nuclear Information System (INIS)

1976-01-01

An improved, simplified radioimmunoassay method for the in vitro determination of L-triiodo-thyronine in unextracted blood serum is described which involves the use of a combination reagent constituted by a buffered solution containing radioactive L-triiodothyronine and an inhibitor for inhibiting the binding of L-triiodothyronine to thyroxine-binding globulin. Optionally the reagent may also include an antiserum containing an antibody capable of immunoreactivity with L-triiodothyronine. Packaged test kits for use in conveniently carrying out the radioimmunoassay are also provided. Certain salts of 8-anilino-1-naphtalene sulfonic acid, which may be regarded as purified forms of the acid, are preferably employed as inhibitors for inhibiting binding of L-triiodothyronine to thyroxine-binding globulin

Standardization of the radioimmunoassay technique for the determination of human gastrin and its clinical application

International Nuclear Information System (INIS)

Peig Ginabredra, M.G.

1989-01-01

It was developed and standardized a system of radioimmunoassay for the determination of gastrin, employing synthetic human gastrin for radioiodination and preparation of standard as well as specific antibody raised rabbits. The hormone was labeled with 125 I by the Cloramine T techique and purified by anion exchange chromatography in QAE-Sephadex A-25, being determined its specific activity. The tracer thus obtained was submitted to analysis of purity by poliacrilamide gel eletrophoresis and precipitation of proteins by trichloroacetic acid. Its stability evaluated according to the time of storage, being its purity and adequation for the use in radioimmunoassay also compared to a tracer obtained from a commercial diagnosis kit. The assays were performed by incubation of radioiodinated gastrin, standard gastrin prepared in plasma free from this hormone (from zero to 500 pmol/l) or samples to be assayed with the antiserum for 4 days at 4 0 C. The separation between the free gastrin and the gastrin bound to the antibody was carried out by adsorption of the free hormone to the charcoal, whose ideal concentration was previously determined. Plasma free from gastrin was obtained from time-expired blood bank plasma submitted to extraction with charcoal. When performed the quality control, this radioimmunoassay was shown specific, accurate, precise and sensitive, allowing the performance of valid assays. Its validation was even confirmed by clear discrimination not only of the gastrin concentration in subjects with very low levels (gastrectomized) and extremely high levels (Zollinger-Ellison syndrome) as well as gastrin concentrations in subjects with other diseases, such as Chagas disease, pernicious anemia and chronic renal failure. (author) [pt

Canine C-peptide for characterization of experimental diabetes in dogs

International Nuclear Information System (INIS)

Fischer, U.; Besch, W.; Freyse, E.-J.

1985-01-01

Radioimmunoassay of canine C-peptide (CCP) was developed for the characterization of endogenous beta cell function in experimentally diabetic dogs. The animals were rendered diabetic by subtotal pancreatectomy and intrasurgical infusion of 2 mg/kg streptozotocin into the superior pancreaticoduodenal artery. After an average duration of diabetes of 5 months the animals showed zero peripheral venous fasting CCP levels with no response to feeding, OGTT/i.v. glucagon loading or i.v. glucose tolerance testing. The data on CCP levels entirely coincided with simultaneously measured plasma IRI levels. In non-diabetic control animals clear-cut CCP increases were observed after all stimuli. The experimental model provided an IDDM-type diabetes without toxic symptoms but with a sufficient exocrine pancreatic function. The comparison showed that plasma IRI analyses would also allow reliable characterization of insulinogenic functions in these animals. (author)

Uncovering the Peptide-Binding Specificities of HLA-C: A General Strategy To Determine the Specificity of Any MHC Class I Molecule

DEFF Research Database (Denmark)

Rasmussen, Michael; Harndahl, Mikkel; Stryhn, Anette

2014-01-01

MHC class I molecules (HLA-I in humans) present peptides derived from endogenous proteins to CTLs. Whereas the peptide-binding specificities of HLA-A and -B molecules have been studied extensively, little is known about HLA-C specificities. Combining a positional scanning combinatorial peptide...... library approach with a peptide-HLA-I dissociation assay, in this study we present a general strategy to determine the peptide-binding specificity of any MHC class I molecule. We applied this novel strategy to 17 of the most common HLA-C molecules, and for 16 of these we successfully generated matrices...... representing their peptide-binding motifs. The motifs prominently shared a conserved C-terminal primary anchor with hydrophobic amino acid residues, as well as one or more diverse primary and auxiliary anchors at P1, P2, P3, and/or P7. Matrices were used to generate a large panel of HLA-C-specific peptide...

Radioimmunoassay of type D oncovirus from continuous J-96 cells

International Nuclear Information System (INIS)

Vlasenkova, N.K.; Altshtejn, A.D.; Zhdanov, V.M.; Kitsak, V.Ya.

1978-01-01

The radioimmunoassay of the J-96 virus and an extract of J-96 cells in the homologous and heterologous systems aimed at detecting antigenic determinants of p25 of Mason-Pfizer virus and group-specific and interspecies antigenic determinants p30 of Rauscher leukaemia virus demonstrated that (1) J-96 virus contains a major internal protein immunologically identical with p25 protein of Mason-Pfizer virus based on the antigenic determinants detectable by the radioimmunoassay used; and (2) no interspecies antigenic determinants characteristic of the major internal protein of mammalian type C viruses were detectable in the J-96 virus or the J-96 cell extract. (author)

Radioimmunoassay for determination of thyroglobulin in human serum

International Nuclear Information System (INIS)

Rodriguez Cabrera, M.E.; Blanca Fernandez, S.; Baldor Navarro, F.; Rodriguez Gonzalez, J.C.

1996-01-01

We described the development and analytical evaluation of a radioimmunoassay with double antibody in liquid phase for human serum thyroglobulin determination using a set of reagents produced in the National Institute of Endocrinology. The reference interval for normal population was 5.7 - 44 ng/ml (X± 2DS; n=170). The intra-assay precipision was 8.1 % (control serum A) and 7.0 (control serum B) and the inter-assay precision was 9.1 % (control serum A) and 9.2 % (control serum B). The sensibility was 4.7 ng/ml and the recovery was 95 %

Determination of a glucose-containing tetrasaccharide in urine by radioimmunoassay

International Nuclear Information System (INIS)

Zopf, D.A.; Levinson, R.E.; Lundblad, A.

1982-01-01

A radioimmunoassay is described that allows rapid determination of a urinary oligosaccharide - Glcα1-6Glcα1-4Glcα1-4Glc [(Glc) 4 ] - at concentrations >2pmol/μl. Antibodies produced in rabbits immunized with the phenethylamine derivative of (Glc) 4 coupled to keyhole limpet hemocyanin bind tritiated (Glc) 4 -alditol. Studies comparing the activities of (Glc) 4 and several of its derivatives and analogues as inhibitors of binding of tritiated (Glc) 4 -alditol show that (Glc) 4 is detected with maximum specificity and sensitivity only after reduction to (Glc) 4 -alditol. Quantitation of (Glc) 4 in urine samples reduced with sodium borohydride gives excellent agreement with a previously used but more laborious method that employs gas-liquid chromatography-mass spectrometry (GLC/MS) (correlation coefficient = 0.98). Studies of the excretion rate of (Glc) 4 in urine of women during pregnancy using the radioimmunoassay method confirm and extend previous results using the GLC/MS method. (Auth.)

Determination of phenobarbital by radioimmunoassay

International Nuclear Information System (INIS)

Yamaoka, A.; Takatori, T.

1979-01-01

A radioimmunoassay for phenobarbital has been studied. Antiphenobarbital antisera were obtained by repeated immunization of rabbits with p-succinamidophenobarbital conjugated to bovine serum albumin. Less than 0.2 pmol of phenobarbital could be measured by this procedure. The specificity of the antibodies was directed to substituents on the nitrogen atoms of the barbituric rings as well as to substituents at the carbon 5-position of the ring. (Auth.)

Determination of serum IgD radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Fayol, V.; Hartmann, D.J.; Sabbagh, I.; Ville, G.

1986-01-01

We describe a sensitive liquid phase radioimmunoassay for serum IgD. Extreme values obtained from 85 control patients sera are 0.2 and 121 mg/l with an arithmetic mean of 25 mg/l. In atopic patients (with high serum IgE levels), arithmetic mean is 47 mg/l.

Rapid radioimmunoassay of human apolipoproteins C-II and C-III

Energy Technology Data Exchange (ETDEWEB)

Gustafson, S; Oestlund-Lindqvist, A M; Vessby, B [Uppsala Univ. (Sweden)

1984-06-01

Apolipoprotein (apo) C-II is an activator of lipoprotein lipase, while apo C-III has the ability to inhibit apo C-II activated lipolysis. In order to study further the relationship between lipoprotein lipase mediated hydrolysis and the serum concentrations of apo C-II and apo C-III radioimmunoassays for these apolipoproteins have been developed. Formalin-treated Staphylococcus aureus Cowan I was used for immunoprecipitation and were shown to give rapid uptake of immune complexes that could easily be harvested by centrifugation. The assays were shown to be sensitive (10 ..mu..g/1), specific, precise (inter- and intra-assay coefficients of variation below 10%), rapid (completed in less than 6 h) and simple to perform. Delipidation of serum and lipoproteins had no effect on the results, indicating that the immunologically active sites of apo C-II and apo C-III are exposed to the aqueous environment under assay conditions. Serum apo C-II and apo C-III levels of normolipidaemic subjects were approximately 25 mg/1 and 110 mg/1, respectively. Highly significant positive correlations were found between VLDL apo C-II and VLDL apo C-III, respectively, and VLDL triglycerides, VLDL cholesterol and total serum TG. There was also a highly significant correlation between the HDL cholesterol concentration and the HDL apo C-III concentration.

Beta-endorphin radioimmunoassay: specificity studies

Energy Technology Data Exchange (ETDEWEB)

Colas-Linhart, N.; Perdrisot, R.; Petiet, A.; Bok, B.

1986-01-01

This note describes the technical details of a cerebrospinal fluid (CSF) B-Endorphin (B-End) radioimmunoassay (RIA). We used an antiserum raised in rabbits against human B-End which cross-reacs 100% with B-Lipotrophin (B-Lph). Thus, filtration chromatography is used to separate both peptides. The assay is sensitive (limit detection=14 pmoles/l), reproducible (the intra and inter assay coefficients of variation are 5 and 6% respectively). Specificity studies are performed to verify the cross-reactions with other opioid peptides and the non specific reactions with the biological fluid (CSF). In order to evaluate the effects of iodine-containing contrast media on the RIA, additional standard curves were analyzed in the presence of varying concentrations of two contrast materials.

A sensitive radioimmunoassay of atrial natriuretic peptide in human plasma, using a tracer with an immobilized glycouril agent

International Nuclear Information System (INIS)

Rosmalen, F.M.A.; Tan, A.C.I.T.L.; Benraad, T.J.

1987-01-01

A highly specific and sensitive radioimmunoassay (RIA) for alpha-human atrial natriuretic peptide (hANP[1-28]) in plasma was developed. The assay used a [ 125 I]monoiodotyrosyl-hANP[1-28] tracer, prepared with an immobilized glycouril agent (Protag) and purified by high pressure liquid chromatography (HPLC), and a highly specific antiserum raised against hANP[1-28], coupled to keyhole limpet haemocyanin, in sheep. Plasma was extracted using C-18 Seppak cartridges. A good parallelism was found after dilution prior to extraction of plasma of patients with congestive heart failure (CHF) or of plasma of healthy subjects. Recovery of hANP[1-28] added to plasma was 96%. The limit of detection was 0.8 pg/tube, intra- and inter-assay variation were 9 and 12%, respectively. Mean plasma ANP values in 25 normal persons with a normal salt intake was 26.0 ± 15.5 (± SD) pg/ml. Plasma levels of 18 subjects (7 normals, 11 CHF) were measured using four different antisera after the extraction step. High correlations were found between the values obtained with these four antisera. (Auth.)

Determination of serum IgD radioimmunoassay

International Nuclear Information System (INIS)

Fayol, V.; Hartmann, D.J.; Sabbagh, I.; Ville, G.

1986-01-01

We describe a sensitive liquid phase radioimmunoassay for serum IgD. Extreme values obtained from 85 control patients sera are 0.2 and 121 mg/l with an arithmetic mean of 25 mg/l. In atopic patients (with high serum IgE levels), arithmetic mean is 47 mg/l [fr

Determination of degree of oncologic disease spreading with the use of radioimmunoassay

International Nuclear Information System (INIS)

Chebotareva, Eh.D.; Shishkina, V.V.; Korolev, V.I.; Sklyar, S.Yu.; Kukot', V.A.

1989-01-01

An effort to evaluate the possibility of applying tumor morkers to determine the degree of oncologic desease propagation is made. Radioimmunoassay of 431 patients with tumors with different localization is performed. In patients with lung, esophagus, stomach, rectum cancer the level of carcinoembryonic antigen (CEA) in the blood serum is studied, with mammary gland cancer - the CEA, ferritin and prolactin levels. An increase of CEA level is detected under wide-spread forms of lung, esophagus, stomach and rectum cancer, and an increase of CEA, ferritin and prolactin levels-under mammary gland cancer. It is shown that radioimmunoassay of tumor marker level is quite information content as to the evaluation of tumor process propagation under digestive tract, lung and mammary gland cancer. 12 refs.; 5 tabs

Radioimmunoassay of human plasma protein C

International Nuclear Information System (INIS)

Wang Bocheng; Li Jinquan; Jing Jian; Zhang Manda

1995-01-01

A radioimmunoassay method for the measurement of human plasma protein C (PC) is established. PC was isolated and purified from human plasma. The antisera against PC was obtained by immunizing rabbits. Iodination of PC was carried out with chroramine-T. The sensitivity was 3.94% μg/L, and the assay covered 6.25∼1024 μg/L for PC. The intra-assay and inter-assay CV were 4.4% and 9.68% respectively, with a recovery rate of 104.28%. There was no cross reaction with factor II. The normal value was 3.84 +- 0.34 mg/L in 36 normal persons. Value of 1.03 +-0.41 mg/L was found in 16 patients with fulminating hepatitis complicated with coagulation disturbance. It is an effective approach for the diagnosis of hereditary or acquired PC deficiency and also for the study of thrombotic diseases

Use of radioimmunoassay to study secretory potentialities of β-cells in patients with insulin-independent diabetes mellitus

International Nuclear Information System (INIS)

Balabolkin, M.I.; Sharapov, A.N.

1984-01-01

The nature of insulin and C-peptides secretion in 21 patient with insulin-independent diabetes mellitus (IIDM) with different acetilating phenotype in the course of intravenous glucose loadin is studied by means of the radioimmunoassay. In all patients a different nature of insulin secretion during the first stage is revealed. In the group of fast acetilators an increase in the immuno-reactive insulin (IRI) concentration in the blood serum has been observed, more strongly pronounced in patients with accompanying obesity, whereas in the group of slow acetilators a regular decrease in the IRI level is revealed during this period. The nature of C-peptides secretion in patients with the second type of diabetes mellitus with different acetilator phenotype repeats in the main the IRI dynamics characteristic of fast and slow acetilators. In patients with IIDM with obesity belonging to fast acetilators, the nature of C-peptide secretion has dynamics with differing from IRI

Radioimmunoassay reagent and its use in a radioimmunoassay

International Nuclear Information System (INIS)

Polito, A.J.; Knight, W.S.

1977-01-01

A radioimmunoassay to detect or determine a steroid of the cortisone and aldosterone group has been developed. The invention particularly concerns a steroid derivative containing imidazole group which is radioactively labelled. The invented reagents are labelled with iodine 125. (VJ) [de

Determination of a glucose-containing tetrasaccharide in urine by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Zopf, D.A.; Levinson, R.E. (National Cancer Inst., Bethesda, MD (USA)); Lundblad, A. (University Hospital, Lund (Sweden). Dept. of Clinical Chemistry)

1982-01-15

A radioimmunoassay is described that allows rapid determination of a urinary oligosaccharide - Glc..cap alpha..1-6Glc..cap alpha..1-4Glc..cap alpha..1-4Glc ((Glc)/sub 4/) - at concentrations >2pmol/..mu..l. Antibodies produced in rabbits immunized with the phenethylamine derivative of (Glc)/sub 4/ coupled to keyhole limpet hemocyanin bind tritiated (Glc)/sub 4/-alditol. Studies comparing the activities of (Glc)/sub 4/ and several of its derivatives and analogues as inhibitors of binding of tritiated (Glc)/sub 4/-alditol show that (Glc)/sub 4/ is detected with maximum specificity and sensitivity only after reduction to (Glc)/sub 4/-alditol. Quantitation of (Glc)/sub 4/ in urine samples reduced with sodium borohydride gives excellent agreement with a previously used but more laborious method that employs gas-liquid chromatography-mass spectrometry (GLC/MS) (correlation coefficient = 0.98). Studies of the excretion rate of (Glc)/sub 4/ in urine of women during pregnancy using the radioimmunoassay method confirm and extend previous results using the GLC/MS method.

Radioimmunoassay for biopterin

Energy Technology Data Exchange (ETDEWEB)

Nagatsu, T; Yamaguchi, T; Kato, T [Tokyo Inst. of Tech. (Japan); Sugimoto, T; Matsuura, S

1979-06-01

Specific antibodies against biopterin, neopterin, and 6,7-dimethylpterin were prepared and a new type of radioimmunoassay, to which these pterins were subjected was developed. This new type of radioimmunoassay was used to determine biopterin in human urine. Specific antiserum against biopterin did not crossreact significantly with tetrahydro-biopterin, dihydro-biopterin, neopterin, 6,7-dimethylpterin, pterin, or folic acid and showed 30% binding of biopterinyl-caproyl- ( /sup 125/I ) tyramide at a dilution of 1:800. The antisera against neopterin and dimethylpterin also showed a high specificity and did not cross-react significantly with the other pterins. The sensitivity of the radioimmunoassay was increased about ten-fold by pre-incubating the antiserum with 6,7-dimethylpterinyl-caproyl to remove antibodies against the caproic acid moiety of the biopterin conjugate. The recovery of biopterin or tetrahydro-biopterin added human urine was nearly 100% according to this type of radioimmunoassay, and the biopterin concentrations in the urine that were obtained by means of this type of radioimmunoassay showed a fairly good agreement with the values obtained by means of bioassay. The biopterin contents per milliliter of human urine showed considerable variations depending on the subjects, but those per milligram of creatinine were found to be fairly constant in normal subjects. Therefore, biopterin concentrations per milligram of creatinine in human urine may be a good indicator of biopterin metabolism in clinical chemistry. This new type of radioimmunoassay is simple, highly specific, and reproducible. Therefore, it may be very useful for the screening of atypical phenylketonuria due to biopterin deficiency and also for the study of the pathogenesis of various biopterin metabolic diseases.

Radioimmunoassay for biopterin

International Nuclear Information System (INIS)

Nagatsu, Toshiharu; Yamaguchi, Tokio; Kato, Takeshi; Sugimoto, Takashi; Matsuura, Sadao.

1979-01-01

Specific antibodies against biopterin, neopterin, and 6,7-dimethylpterin were prepared and a new type of radioimmunoassay, to which these pterins were subjected was developed. This new type of radioimmunoassay was used to determine biopterin in human urine. Specific antiserum against biopterin did not crossreact significantly with tetrahydro-biopterin, dihydro-biopterin, neopterin, 6,7-dimethylpterin, pterin, or folic acid and showed 30% binding of biopterinyl-caproyl- ( 125 I ) tyramide at a dilution of 1:800. The antisera against neopterin and dimethylpterin also showed a high specificity and did not cross-react significantly with the other pterins. The sensitivity of the radioimmunoassay was increased about ten-fold by pre-incubating the antiserum with 6,7-dimethylpterinyl-caproyl to remove antibodies against the caproic acid moiety of the biopterin conjugate. The recovery of biopterin or tetrahydro-biopterin added human urine was nearly 100% according to this type of radioimmunoassay, and the biopterin concentrations in the urine that were obtained by means of this type of radioimmunoassay showed a fairly good agreement with the values obtained by means of bioassay. The biopterin contents per milliliter of human urine showed considerable variations depending on the subjects, but those per milligram of creatinine were found to be fairly constant in normal subjects. Therefore, biopterin concentrations per milligram of creatinine in human urine may be a good indicator of biopterin metabolism in clinical chemistry. This new type of radioimmunoassay is simple, highly specific, and reproducible. Therefore, it may be very useful for the screening of atypical phenylketonuria due to biopterin deficiency and also for the study of the pathogenesis of various biopterin metabolic diseases. (J.P.N.)

Intracellular Signalling by C-Peptide

Directory of Open Access Journals (Sweden)

Claire E. Hills

2008-01-01

Full Text Available C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na+/K+ ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.

Radioimmunoassay for determination of tumor markers in the diagnosis of rectal cancer recurrences

International Nuclear Information System (INIS)

Ozhiganov, E.L.; Kuznetsova, L.F.

1991-01-01

The levels of tumor markers were determined in patients with rectal cancer recurrences by radioimmunoassay. An increase in a CEA level was observed most frequently. An increase in the levels of α-fetoprotein, ferritin and β 2 -microglobulin was observed. It was shown that the most specific and effective diagnostic test of rectal cancer recurrences was the determination of a CEA level

A beta-endorphin radioimmunoassay: specificity studies

International Nuclear Information System (INIS)

Colas-Linhart, N.; Perdrisot, R.; Petiet, A.; Bok, B.

1986-01-01

This note describes the technical details of a cerebrospinal fluid (CSF) B-Endorphin (B-End) radioimmunoassay (RIA). We used an antiserum raised in rabbits against human B-End which cross-reacs 100% with B-Lipotrophin (B-Lph). Thus, filtration chromatography is used to separate both peptides. The assay is sensitive (limit detection=14 pmoles/l), reproducible (the intra and inter assay coefficients of variation are 5 and 6% respectively). Specificity studies are performed to verify the cross-reactions with other opioid peptides and the non specific reactions with the biological fluid (CSF). In order to evaluate the effects of iodine-containing contrast media on the RIA, additional standard curves were analyzed in the presence of varying concentrations of two contrast materials [fr

Analysis of the brain ACTH-immunoreactive peptide spectrum in inbred mice

International Nuclear Information System (INIS)

Fedoseev, Yu.L.; Blednov, Yu.A.; Seredenin, S.B.

1987-01-01

Mice of the BALB/c (C) and C57BL/6 (B6) strains, characterized by high and low emotionality respectively in open field tests, have been shown to differ considerably in both the initial level and the time course of changes in the plasma ACTH concentration after exposure to stress in an open field and after administration of a benzodiazepine tranquilizer. The ACTH concentration in the pituitary gland of animals of these lines also differs. The ACTH molecule is known to contain regions with neurotropic activity. It can therefore be postulated that differences in the level of this hormone and the products of its bioconversion in the brain are an essential factor in the mechanisms of formation of the hereditary features of emotional behavior. In this first stage of this investigation, represented in this paper and undertaken to test this hypothesis, spectra of ACTH-immunoreactive peptides were studied in chromatographic fractions of an acid brain extract as well as in the blood plasma of mice belonging to B6 and C lines and their hybrids. The peptides were determined by radioimmunoassay

Radio-immunoassays for glucagon-like peptides 1 and 2 (GLP-1 and GLP-2)

DEFF Research Database (Denmark)

Orskov, C; Holst, J J

1987-01-01

in rabbits after carbodiimide conjugation of peptides to BSA. The selected antisera showed neither mutual cross-reactivity nor cross-reacted with any other peptide of the glucagon family. Trypsin digestion experiments showed that both antisera were directed against the C-terminus of the antigen peptides...

Plasma concentration of atrial natriuretic peptide in normal pregnant women and in pregnant women with preeclampsia

DEFF Research Database (Denmark)

Mikkelsen, A L; Schütten, G; Asping, U

1991-01-01

Plasma concentration of atrial natriuretic peptide (ANP) was determined in pregnant women with preeclampsia, in normal pregnant and in nonpregnant women by a specific radioimmunoassay. Results did not show important differences between nonpregnant controls and normal pregnant women, but a signifi......Plasma concentration of atrial natriuretic peptide (ANP) was determined in pregnant women with preeclampsia, in normal pregnant and in nonpregnant women by a specific radioimmunoassay. Results did not show important differences between nonpregnant controls and normal pregnant women......, but a significant rise was seen in women with preeclampsia compared to nonpregnant controls. Marked interindividual variation was found in all three groups. The mechanism of ANP release may differ between those women with normal pregnancy and those with preeclampsia. It is unclear whether the increased level of ANP...... in preeclampsia is an effect or a cause of the disease....

Application of reaction type of C-peptide release test in diabetes mellitus

International Nuclear Information System (INIS)

Chen Dong; Duan Wenruo; He Juan; Lu Zhenfang

2001-01-01

The author is to confirm the effect of C-peptide release test and types of release reaction in appraisal of pancreas function of β-cell and selection of treatment for diabetes mellitus (DM) patients. The serum C-peptide release test of 67 normal controls and 217 DM patients were determined by RIA, and the results were analyzed and compared. C-peptide release test can reflect the pancreas function of β-cell better, the peak of C-peptide ≥ 0.6 nmol/L after lunch can be the limit of whether to reduce the level of blood glucose only by oral drug. The authors should adjust the treatment through analyzing the type of C-peptide release reaction. C-peptide release test is very important in evaluating the pancreas function of β-cell, classifying the type of DM and selecting the treatment

Handbook of radioimmunoassay

International Nuclear Information System (INIS)

Abraham, G.E.

1977-01-01

This handbook provides clear, detailed descriptions of ways to set up radioimmunoassay procedures for a variety of polypeptides and low molecular weight compounds. It covers extensively the subjects of statistical evaluation of radioimmunoassay, instrumentation in radioimmunoassay, and radiation safety in the performance of radioimmunoassay. Related nonconventional methods are also discussed. Contributors to this handbook have presented their own procedures for performing the radioimmunoassay and their rationale for choosing particular reagents and conditions. Emphasis is on providing sufficient information to enable relatively inexperienced immunoassayists to set up assay systems with a minimum of difficulty

Antigenic relatedness of primate procollagens as determined by a competitive radioimmunoassay

International Nuclear Information System (INIS)

Taubman, M.B.; Goldberg, B.

1978-01-01

A radioimmunoassay specific for the nonhelical carboxy terminal portion of human type I procollagen was used to study the antigenic relatedness of primate procollagens. The assay identified reactive antigen in primate sera and in the media of primate fibroblast cultures. The displacement curves generated in the assay indicated that human and ape type I procollagens have antigenically identical carboxy terminal determinants which are partially cross-reactive with those from Old and New World monkeys. (author)

C-Peptide Is a Sensitive Indicator for the Diagnosis of Metabolic Syndrome in Subjects from Central Mexico.

Science.gov (United States)

Gonzalez-Mejia, M Elba; Porchia, Leonardo M; Torres-Rasgado, Enrique; Ruiz-Vivanco, Guadalupe; Pulido-Pérez, Patricia; Báez-Duarte, Blanca G; Pérez-Fuentes, Ricardo

2016-05-01

Metabolic Syndrome (MetS) is associated with elevated risk for developing diabetes and cardiovascular disease. A key component of MetS is the development of insulin resistance (IR). The homeostatic model assessment (HOMA) model can determine IR by using insulin or C-peptide concentrations; however, the efficiency of insulin and C-peptide to determine MetS has not been compared. The aim of the study was to compare the efficiency of C-peptide and insulin to determine MetS in Mexicans. Anthropometrics, glucose, insulin, C-peptide, triglycerides, and high-density lipoproteins were determined in 156 nonpregnant females and 114 males. Subjects were separated into normal or positive for MetS. IR was determined by the HOMA2 calculator using insulin or C-peptide. Correlations were calculated using the Spearman correlation coefficient (ρ). Differences between correlations were determined by calculating Steiger's Z. The sensitivity was determined by the area under receiver operating characteristics curve (AUC) analysis. Independent of the MetS definition [Adult Treatment Panel III (ATP III), International Diabetes Federation (IDF), or World Health Organization (WHO)], C-peptide and insulin were significantly higher in MetS subjects (P indicator of MetS. Since C-peptide has recently emerged as a biomolecule with significant importance for inflammatory diseases, monitoring C-peptide levels will aid clinicians in preventing MetS.

Radioimmunoassay compared to an enzymatic method for serum bile acid determination

International Nuclear Information System (INIS)

Samuelson, K.

1980-01-01

Radioimmunoassay (RIA) of cholic and chenodeoxycholic acid was compared to a total bile acid determination with 3α-hydroxysteroid dehydrogenase (3α HSD) and a gas liquid chromatographic (GLC) determination of individual bile acids. When sera from patients with increased bile acid concentration were analysed the results indicated a good correlation between GLC and the other methods. Analysis of sera from healthy subjects indicated a good correlation between GLC and RIA. No correlation existed between RIA and 3α-HSD when serum bile acids were analysed in healthy subjects partly due to the presence of varying amounts of secondary bile acids. (author)

New sensitive direct radioimmunoassay for human plasma renin and its clinical application

International Nuclear Information System (INIS)

Higaki, J.; Ogihara, T.; Imai, N.; Kumahara, Y.; Hontani, S.; Nishiura, M.; Ogawa, H.; Hirose, S.; Murakami, K.

1984-01-01

A new sensitive direct radioimmunoassay for human plasma renin has been developed. Renin was purified from Haas' preparation utilizing a pepstatin-C 6 -Sepharose affinity chromatography. Antiserum, prepared by immunizing rabbits with the purified renin, was used for the direct radioimmunoassay at a final dilution of 1:30,000. The antibody was specific for human renal and plasma renin, but did not cross-react with cathepsin D, trypsin, or renins of mouse, dog, and rat. Radioimmunoassay was performed by the double antibody technique using the delayed tracer addition method. In this method, a standard curve was obtained over a range from 0.2 to 8.0 ng/ml. The values from this assay correlated well with total renin activity measured as the generation rate of angiotensin I after trypsin activation, but correlated weakly with active renin activity. This finding disclosed that both active and inactive renin were detected by this method. In normal participants, plasma renin concentration determined by direct radioimmunoassay was increased by standing and furosemide injection. The plasma renin concentration determined by direct radioimmunoassay of patients with essential hypertension was not significantly different from values in normal controls. The values were higher in patients with renovascular hypertension, malignant hypertension and Bartter's syndrome, but lower in patients with primary aldosteronism than in normal controls. 20 references, 7 figures

Programs for data processing in radioimmunoassay using the HP-41C programmable calculator

International Nuclear Information System (INIS)

1981-09-01

The programs described provide for analysis, with the Hewlett Packard HP-41C calculator, of counting data collected in radioimmunoassays or other related in-vitro assays. The immediate reason for their development was to assist laboratories having limited financial resources and serious problems of quality control. The programs are structured both for ''off-line'' use, with manual entry of counting data into the calculator through the keyboard, and, in a slightly altered version, for ''on-line'' use, with automatic data entry from an automatic well scintillation counter originally designed at the IAEA. Only the off-line variant of the programs is described. The programs determine from appropriate counting data the concentration of analyte in unknown specimens, and provide supplementary information about the reliability of these results and the consistency of current and past assay performance

Qualitative determination of tubulin by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Joniau, M [Louvain Univ. (Belgium). Interdisciplinary Research Centre; Brabander, M de [Janssen Pharmaceutica, Beerse (Belgium). Lab. of Oncology; Mey, J de [Brussels Univ. (Belgium). Medische Stichting Koningin Elisabeth; Hoebeke, J [Brussels Univ. (Belgium). Lab. of Biochemical Pathology

1977-06-15

The use of an antiserum specific for tubulin in cytochemical studies was described previously. Here a report is presented on its application in a radioimmunoassay for tubulin useful in the concentration range of 0.5 to 20 ..mu..g tubulin/ml. The advantages of this technique over the classical colchicine binding assay are discussed in terms of sensitivity and nonsusceptibility to the degree of polymerization and thermal denaturation of tubulin allowing its application to cell culture homogenates.

C-Peptides for diagnostics and therapy: a veterinary medicine point of view

Directory of Open Access Journals (Sweden)

Derek A. Rosenfield

Full Text Available ABSTRACT: Empirical studies proved that C-peptides are performing numerous intrinsic biological roles, and serve as a marker for pancreatic performance analysis. Since the last decade, C-peptide assays for differential diagnosis in veterinary diabetic patients are becoming more available, but still only for a very limited number of species. Studies on C-peptide as a diagnostic tool, therapy for associated complications, or as replacement therapies for C-peptide deficiency still showed not to be a common practice in veterinary medicine. This review was conducted to determine the potential importance of C-peptide in Veterinary Medicine, relevant in the diagnosis of diabetes and for other metabolic processes, as well as its proposed therapeutic benefits. Numerous articles were identified that reported positive results in their experimental studies, whether C-peptide as a biomarker for pancreatic performance in dogs, cats, and horses, as a non-invasive method to monitor nutritional status in primates, or to investigate its potential therapeutic benefits for diabetes-related illnesses.

Protective effect of C-peptide on experimentally induced diabetic nephropathy and the possible link between C-peptide and nitric oxide.

Science.gov (United States)

Elbassuoni, Eman A; Aziz, Neven M; El-Tahawy, Nashwa F

2018-06-01

Diabetic nephropathy one of the major microvascular diabetic complications. Besides hyperglycemia, other factors contribute to the development of diabetic complications as the proinsulin connecting peptide, C-peptide. We described the role of C-peptide replacement therapy on experimentally induced diabetic nephropathy, and its potential mechanisms of action by studying the role of nitric oxide (NO) as a mediator of C-peptide effects by in vivo modulating its production by N G -nitro-l-arginine methyl ester (L-NAME). Renal injury markers measured were serum urea, creatinine, tumor necrosis factor alpha, and angiotensin II, and malondialdehyde, total antioxidant, Bcl-2, and NO in renal tissue. In conclusion, diabetic induction resulted in islet degenerations and decreased insulin secretion with its metabolic consequences and subsequent renal complications. C-Peptide deficiencies in diabetes might have contributed to the metabolic and renal error, since C-peptide treatment to the diabetic rats completely corrected these errors. The beneficial effects of C-peptide are partially antagonized by L-NAME coadministration, indicating that NO partially mediates C-peptide effects.

Proinsulin C-peptide interferes with insulin fibril formation

International Nuclear Information System (INIS)

Landreh, Michael; Stukenborg, Jan-Bernd; Willander, Hanna; Söder, Olle; Johansson, Jan; Jörnvall, Hans

2012-01-01

Highlights: ► Insulin and C-peptide can interact under insulin fibril forming conditions. ► C-peptide is incorporated into insulin aggregates and alters aggregation lag time. ► C-peptide changes insulin fibril morphology and affects backbone accessibility. ► C-peptide may be a regulator of fibril formation by β-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic β-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

Proinsulin C-peptide interferes with insulin fibril formation

Energy Technology Data Exchange (ETDEWEB)

Landreh, Michael [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden); Stukenborg, Jan-Bernd [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Willander, Hanna [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Soeder, Olle [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Johansson, Jan [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-751 23 Uppsala (Sweden); Joernvall, Hans, E-mail: Hans.Jornvall@ki.se [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden)

2012-02-17

Highlights: Black-Right-Pointing-Pointer Insulin and C-peptide can interact under insulin fibril forming conditions. Black-Right-Pointing-Pointer C-peptide is incorporated into insulin aggregates and alters aggregation lag time. Black-Right-Pointing-Pointer C-peptide changes insulin fibril morphology and affects backbone accessibility. Black-Right-Pointing-Pointer C-peptide may be a regulator of fibril formation by {beta}-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic {beta}-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

A linear graph for digoxin radioimmunoassay

International Nuclear Information System (INIS)

Smith, S.E.; Richter, A.

1975-01-01

The determination of drug or hormone concentrations by radio-immunoassay involves interpolation of values for radioisotope counts within standard curves, a technique which requires some dexterity in curve drawing and which results in some inaccuracy in practice. Most of the procedures designed to overcome these difficulties are complex and time-consuming. In radioimmunoassays involving saturation of the antibody-binding sites a special case exists in that the bound radioactivity is directly proportional to the specific activity of the ligand in the system. Thus a graph of the ratio of radioactivity bound in the absence to that in the presence of added non-radioactive ligand is linear against the concentration of added ligand (Hales,C.N., and Randle, P.J., 1963, Biochem. J., vol. 88, 137). A description is given of a simple and convenient modification of their method, and its application to the routine clinical determination of digoxin using a commercial kit (Lanoxitest β digoxin radioimmunoassay kit, Wellcome Reagents Ltd.). Specially constructed graph paper, which yields linearity with standard solutions, was designed so that it could be used directly without data transmission. The specific activity function appears as the upper arithmetical horizontal scale; corresponding values of the concentration of non-radioactive ligand in the solution added were individually calculated and appear on the lower scale opposite the appropriate values of the upper scale. The linearity of the graphs obtained confirmed that binding of digoxin was approximately constant through the range of clinical concentrations tested (0.5 to 8ng/ml), although binding declined slightly at higher concentrations. (U.K.)

Influence of C-Peptide on Glucose Utilisation

Directory of Open Access Journals (Sweden)

B. Wilhelm

2008-01-01

Full Text Available During the recent years, multiple studies demonstrated that C-peptide is not an inert peptide, but exerts important physiological effects. C-peptide binds to cell membranes, stimulates the Na,K-ATPase and the endothelial nitric oxide (NO synthase. Moreover, there is evidence that C-peptide decreases glomerular hyperfiltration and increases glucose utilisation. Nevertheless, there is still limited knowledge concerning mechanisms leading to an increased glucose utilisation either in rats or in humans. The aim of this paper is to give an overview over the published studies regarding C-peptide and glucose metabolism from in vitro studies to longer lasting studies in humans.

Intrinsic factor in human amniotic fluid as determined by radioimmunoassay

International Nuclear Information System (INIS)

Wahlstedt, V.; Stenman, U.-H.; Ylinen, K.; Graesbeck, R.

1983-01-01

The intrinsic factor (IF) concentration in 55 human amniotic fluid specimens was determined by radioimmunoassay (RIA). The antiserum was produced by immunizing rabbits with the cobalamin-IF complex isolated from human gastric juice. The median concentration of IF was 0.17 nmol/l and the extreme values <0.07-2.51 nmol/l. Three specimens with a clearly elevated level (0.96, 1.11 and 2.51 nmol/l) were observed. The highest value was associated with a fetal malformation, viz. obstruction of the proximal gut. There was no evident correlation between the concentration of IF in amniotic fluid and gestational age. (author)

Immunochemical heterogeneity of calcitonin in man: effect on radioimmunoassay

International Nuclear Information System (INIS)

Snider, R.H.; Moore, C.F.

1977-01-01

Determinations of blood levels of human calcitonin by radioimmunoassay have varied considerably in different laboratories. Much of the controversy over calcitonin levels can be attributed to the multiplicity of immunoreactive forms of the hormone (iCT), the differing region specificities of the antisera utilized for measurement by radioimmunoassay, protein effects, different rates of degradation of the various iCT fractions and the specific methodology of the radioimmunoassay

Radioimmunoassay for GRF and CRF in humans

International Nuclear Information System (INIS)

Stalla, G.K.; Losa, M.; Kaliebe, T.; Stalla, J.; Schopohl, J.; Muller, O.A.; Von Werder, K.

1987-01-01

In 1981 the structure of ovine CRF was established. One year later others isolated a 44 amino acid peptide with GH releasing activity from a pancreatic islet cell carcinoma of an acromegalic patient (hp GRF/sup 1-44/). In 1983 the gene of human CRF was cloned and the amino acid sequence of hCRF could be elucidated. It differs in 7 amino acids from oCRF. Many investigators demonstrated the biological activity of these peptides in vitro and in vivo. The aim of the authors study was to establish radioimmunoassays for GRF and hCRF with the synthetic derivates, measure endogenous GFR and CRF and circulating GRF- and CRF-levels after intravenous injection and calculate metabolic clearance rate and half-time of disappearance from serum for both releasing hormones

Determination of plasma oxytocin by radioimmunoassay

International Nuclear Information System (INIS)

Ogawa, Satsuki; Fukuchi, Soitsu; Miura, Tadashi

1978-01-01

A simple radioimmunoassay was applied to the measurement of oxytocin in human plasma. A high specificity of immunoassay was demonstrated by the fact that large excess of angiotensin I and II, and ACTH did not displace labelled oxytocin from the antibody. Lysine-8-vasopressin and arginine-8-vasopressin showed very little cross-reaction in the assay, possessing only 0.002% of the immunological potency of oxytocin. The specific activity of 125 I-oxytocin was 166 μCi/μg. Adsorption and extraction capacities of Florisil were 96.6 +- 2.1% and 85.7 +- 2.5%, respectively. Intra- and inter-assay variability were 7.2 +- 4.9% and 4.3 +- 2.2%, respectively. The sensitivity of the assay was below 1 pg/tube. Normal levels of plasma oxytocin were 0 - 2.2 pg/ml (n=13) in males and 0 - 10.4 pg/ml (n=10) in females. Plasma oxytocin levels in the 39th and 40th weeks of pregnancy were 27.9 +- 4.14 pg/ml (n=4) and 29.8 +- 17.1 pg/ml (n=13), respectively. The levels increased to 33.1 +- 12.1 pg/ml (n=7) and 37.1 +- 17.5 pg/ml (n=7) in the first and third stages of labor, and decreased to 13.6 +- 5.25 pg/ml (n=6) on the 2nd to 8th day after labor. The radioimmunoassay for oxytocin in plasma is considered to be sufficiently applicable for clinical use. (auth.)

Sensitivity and reproducibility of urinary C-peptide as estimate of islet B-cell function in insulin-treated diabetes

DEFF Research Database (Denmark)

Gjessing, H J; Matzen, L E; Faber, O K

1989-01-01

The aims of the present study were to evaluate the ability of urinary C-peptide determination to demonstrate presence of residual insulin secretion, and to evaluate the reproducibility of urinary C-peptide excretion in 125 insulin-treated diabetic patients. C-peptide was determined in two...

Radioimmunoassay for calcitonin gene-related peptide and its measurement in sera of patients with thyroid disease

International Nuclear Information System (INIS)

Yoshida, Hiromi; Morii, Hirotoshi; Hamada, Noboru; Noh, Jaeduk; Ito, Kunihiko.

1992-01-01

To investigate serum levels of calcitonin gene-related peptide (CGRP), we developed a sensitive radioimmunoassay (RIA). RIA for CGRP in serum can present problems: the serum may degradate the tracer during incubation and suppress the antigen-antibody reaction. We avoided these problems by using aprotinin and CGRP-free serum instead of a buffer for the standard curve. We detected serum CGRP in all 39 healthy subjects when CGRP-free serum was not used for the standard curve, but 34 of these subjects had serum CGRP levels below the detection limit (<80 pmol/l) when CGRP-free serum was used for the standard curve. We defined the normal range for serum CGRP as below 100.8 pmol/l, which was the maximum level found in the healthy subjects. We studied serum levels of this peptide in patients with thyroid disease, because the thyroid may be one origin of circulating CGRP. Four of 10 patients with medullary thyroid carcinoma had elevated serum levels of CGRP. Seven of 24 patients with subacute thyroiditis had elevated serum levels of CGRP, but at least one year after clinical recovery, CGRP was undetectable in all. Seven of the 37 patients with hypothyroidism had elevated serum levels of CGRP. None of the patients with hyperthyroidism, adenomatous goiter, thyroid adenoma, or thyroid carcinoma had elevated serum CGRP levels. It is necessary to use a standard curve obtained by the addition of aprotinin and CGRP-free serum to the assay standards to measure serum CGRP levels. Some patients with subacute thyroiditis, hypothyroidism, or medullary thyroid carcinoma had elevated serum CGRP levels. (author)

Clinical significance of the radioimmunological determination of C-peptide

International Nuclear Information System (INIS)

Dudczak, R.; Waldhaeusl, W.

1979-01-01

The aim of this study was to investigate the relationship of metabolic control to insulinogenic reserve in insulin-dependent diabetics. Thus, the secretory reserve of the pancreatic beta cell was estimated in insulin-dependent diabetics by measuring changes in peripheral serum immunoreactive C-peptide (IRCP) concentrations in response to intravenous arginine (n = 19; 0.5 g/kg,t = 30 min) or glibenclamide-glucose (n = 6; 2 mg HB 419 - 0.33 g/kg intravenously). In the majority of ''stable'' diabetics a small secretory reserve of the beta cell was demonstrated, but both the absolute and relative increase in IRCP was reduced after intravenous arginine or glibenclamide-glucose in comparison with normal controls. In ''unstable'' diabetics a decreased basal concentration of IRCP, significantly smaller than that seen in ''stable'' diabetics (p < 0.01), was accompanied by a complete lack of IRCP release on intravenous arginine administration. Thus, we conclude that the radioimmunological determination of IRCP is of clinical interest in assessing the residual secretory capacity of the beta cell in insulin-dependent diabetics. In revealing a lack of insulin this diagnostic tool seems to detect a group of potentially ''unstable'' diabetics in need of strict observation, which would minimize the risks of bad metabolic control. (author)

Clinical significance of the radioimmunological determination of C-peptide

Energy Technology Data Exchange (ETDEWEB)

Dudczak, R; Waldhaeusl, W [Vienna Univ. (Austria). 1. Medizinische Klinik

1979-10-12

The aim of this study was to investigate the relationship of metabolic control to insulinogenic reserve in insulin-dependent diabetics. Thus, the secretory reserve of the pancreatic beta cell was estimated in insulin-dependent diabetics by measuring changes in peripheral serum immunoreactive C-peptide (IRCP) concentrations in response to intravenous arginine (n = 19; 0.5 g/kg,t = 30 min) or glibenclamide-glucose (n = 6; 2 mg HB 419 - 0.33 g/kg intravenously). In the majority of stable diabetics a small secretory reserve of the beta cell was demonstrated, but both the absolute and relative increase in IRCP was reduced after intravenous arginine or glibenclamide-glucose in comparison with normal controls. In unstable diabetics a decreased basal concentration of IRCP, significantly smaller than that seen in stable diabetics (p < 0.01), was accompanied by a complete lack of IRCP release on intravenous arginine administration. Thus, we conclude that the radioimmunological determination of IRCP is of clinical interest in assessing the residual secretory capacity of the beta cell in insulin-dependent diabetics. In revealing a lack of insulin this diagnostic tool seems to detect a group of potentially unstable diabetics in need of strict observation, which would minimize the risks of bad metabolic control.

Human aldolase B subunit-specific radioimmunoassay

International Nuclear Information System (INIS)

Asaka, M.; Alpert, E.

1983-01-01

A radioimmunoassay was developed for the direct quantification of aldolase B in human serum and tissues. The method is a double-antibody radioimmunoassay technique using radioiodinated aldolase B homopolymer as ligand, chicken antibodies to aldolase B and rabbit antibodies to chicken IgG. This radioimmunoassay was shown to be specific for the aldolase B subunit, with no cross-reactivity with either human aldolase A subunit or homopolymeric human aldolase C (C 4 ). The lowest measurable amount by this method was 2 ng/ml. Aldolase B is predominantly found in normal liver tissue, with relatively-high aldolase B levels also observed in kidney. Aldolase B levels in the serum obtained from 11 normal subjects ranged from 23 to 38 ng/ml, with a mean of 28.5 +- 9.2 (S.D.) ng/ml. Almost all of patients with hepatitis had serum aldolase B levels greater than 30 ng/ml. In cancer patients, serum aldolase B was slightly elevated in patients with metastatic liver cancer and primary lever cell carcinoma, whereas no elevation of serum aldolase B was shown in patients without liver metastasis. (Auth.)

Theoretical and practical application of radioimmunoassays

International Nuclear Information System (INIS)

Sokolowski, G.; Wood, W.G.

1981-01-01

This book describes experiences made not only in developing and producing commercial reagent kits, but also those made in university research and diagnostic laboratories. The fundamental principles (radioactivity, immunoassay) are explained briefly and tersely. Then the components of the radioimmunoassay are described in detail and illustrated by selected practical examples (production of antibodies, separation of bound and free portions, standards). This chapter is followed by systematic instructions for composing a radioimmunoassay. The actual conditions of the complex problem of quality safety is explained, a field in which particularly the authors are to be regarded as pioneers. Finally an outlook indicates that radioactive alternatives, incorporating the principle of immunologic determinations methods, are available or will be developed for at least a few radioimmunoassays. (orig./MG) [de

Specific bile acid radioimmunoassays for separate determinations of unconjugated cholic acid, conjugated cholic acid and conjugated deoxycholic acid in serum and their clinical application

International Nuclear Information System (INIS)

Matern, S.; Gerok, W.

1977-01-01

Specific radioimmunoassays for separate determinations of serum unconjugated cholic, conjugated cholic and conjugated deoxycholic acids have been developed. Prior to the radioimmunoassay, extraction of serum bile acids was performed with Amberlite XAD-2. Unconjugated cholic acid was separated from glyco- and taurocholic acids by thin-layer chromatography. At 50% displacement of bound labeled glyco[ 3 H]cholic acid using antiserum obtained after immunization with cholic acid-bovine serum albumin-conjugate the cross-reactivity of taurocholic acid was 100%, cholic acid 80%, glycochenodeoxycholic acid 10%, chenodeoxycholic acid 7%, conjugated deoxycholic acid 3%, and conjugated lithocholic acid 3 H]cholic acid was linear on a logit-log plot from 5 to 80 pmol of unlabeled glycocholic acid. Fasting serum conjugated cholic acid in healthy subjects was 0.68 +- 0.34 μmol/l. Unconjugated cholic acid was determined by a solid phase radioimmunoassay using the cholic acid antibody chemically bound to Sepharose. The displacement curve of [ 3 H]cholic acid in the solid phase radioimmunoassay was linear on a logit-log plot from 5 to 200 pmol of unlabeled cholic acid. The coefficient of variation between samples was 5%. Fasting serum conjugated deoxycholic acid concentrations in 10 healthy subjects ranged from 0.18 to 0.92 μmol/l determined by a radioimmunoassay using antiserum obtained after immunization with deoxycholic acid-bovine serum albumin-conjugate. The clinical application of these bile acid radioimmunoassays is shown by an 'oral cholate tolerance test' as a sensitive indicator of liver function and by an 'oral cholyglycine tolerance test' as a useful test for bile acid absorption. (orig.) [de

Development and evaluation of the determination of the polyamines spermine and spermidine by radioimmunoassay

International Nuclear Information System (INIS)

Shaw, G.G.

1985-08-01

In 1975 Bartos et al described a radio-immunoassay for spermine which lacked specificity. In subsequent years the same group has reported the production of a specific antibody to spermidine and to spermine. The availability of specific antibodies potentially transformed the usefulness of radioimmunoassay from a system useful for semi-quantitative screening to one with a much broader applicability in the area of quantitative assay of polyamines. It was claimed that the assay would quantify as little as 10 picogrammes of spermidine or spermine. Up to 1982 when the present project commenced no other groups had reported using the Bartos assay. The present study was therefore indicated in order to determine whether specific antibodies could be produced in laboratories other than those of the Bartos group and to validate the assay by comparing it with the much more widely used and well established HPLC methods currently available

A Study of the Insulin and the C-Peptide Responses to Oral Glucose Load in Nondiabetic and Diabetic Subjects

Energy Technology Data Exchange (ETDEWEB)

Lee, Myung Chul; Choi, Sung Jae; Kim, Eung Jin; Koh, Chang Soon; Min, Hun Ki [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1977-03-15

The present study was undertaken to evaluate the significance of the insulin and the C-peptide response to oral glucose loads in normal and diabetic subjects and to establish the effects of the obesity. In this study, the authors have measured plasma insulin and C-peptide by means of radioimmunoassay in 10 nonobese normal, 5 obese normal, 13 nonobese moderate diabetic patients, 9 obese moderate diabetic patients and 9 severe diabetic patients. The results obtained were as follows; 1) In 10 nonobese normal subjects, the plasma insulin level at fasting state and at 30, 60, 90, and 120 min after oral glucose loads were 15.7+-3.4, 48.3+-9.8, 40.4+-6.7, 37.4+-6.5 and 26.0+-4.2 uU/ml (Mean+-S.E.) and C-peptide were 1.9+-0.3, 3.9+-0.6, 6.3+-0.6, 5.7+-0.5 and 4.0+-0.5 ng/ml. The change of C-peptide was found to go almost parallel with that of insulin and the insulin value reaches to the highest level at 30 min whereas C-peptide reaches to its peak at 60 min.. 2) The plasma insulin level in 5 obese normal subjects were 38.9+-12.3, 59.5+-12.3, 59.2+-17.1, 56.1+-20.0 and 48.4+-17.2 uU/ml and the C-peptide were 5.5+-0.4, 6.8+-0.5, 7.9+-0.8, 7.9+-0.8 and 7.8+-2.0 ng/ml. The insulin response appeared to be greater than nonobese normal subjects. 3) In 13 nonobese moderate diabetic patients, the plasma insulin levels were 27.1+-4.9, 44.1+-6.0, 37.3+-6.6, 35.5+-8.1 and 34.7+-10.7 uU/ml and the C-peptide levels were 2.7+-0.4, 4.9+-0.7, 6.5+-0.5, 7.0+-0.3 and 6.7+-1.0 ng/ml. There was little significance compared to nonobese normal groups but delayed pattern is noted. 4) In 9 obese moderated diabetic patients, the plasma insulin levels were 22.1+-7.9, 80.0+-19.3, 108.0+-27.0, 62.0+-17.6 and 55.5+-10.l uU/ml and the C-peptide levels were 5.2+-0.4, 8.0+-1.0, 10.4+-1.6, 10.4+-1.7 and 10.1+-1.0 ng/ml and its response was also greater than that of nonobese moderate diabetic patients. 5) The plasma insulin concentrations in 9 severe diabetic subjects were 8.0+-3.8, 12.1+-3.5, 16.8+-4.6, 19

Pancreatic elastase in human serum. Determination by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Geokas, M.C. (Univ. of California, Davis); Brodrick, J.W.; Johnson, J.H.; Largman, C.

1977-01-10

This study demonstrates that a serine endopeptidase of pancreatic origin (elastase 2) circulates in human blood. A specific and highly sensitive radioimmunoassay has been developed for pancreatic elastase 2 in human serum. The inactivation of elastase 2 employed as radioiodinated tracer with an active site-specific reagent (phenylmethanesulfonyl fluoride) was necessary to prevent its binding by serum ..cap alpha../sub 1/-antitrypsin and ..cap alpha../sub 2/-macroglobulin while maintaining its immunoreactivity. The assay is based upon competition of standard human pancreatic elastase 2 with /sup 125/I-labeled phenylmethanesulfonyl elastase 2 for specific antibody binding sites, after which a second antibody precipitation step is used to separate bound from free /sup 125/I-labeled phenylmethanesulfonyl elastase 2. The minimum detectable concentration of elastase 2 was 0.9 ng/ml. The average normal fasting serum level determined was 71 ng/ml, approximately 80-fold greater than the minimum detectable amount.

Radioimmunoassay of Alb, β2-M and THP

International Nuclear Information System (INIS)

Xie Zhiyuan; Li Shengqi; Ren Shusheng; Chen Yuying

1993-01-01

The combined determination of β 2 -M, THP, Alb, IgG may be used as the sensitive indication of the early degeneration of kidney function. The authors observed 107 cases, and found that the anomalous examine-out ratios of hemorrhage β 2 -M and UTHP are 50.75% and 65.67% respectively, 1.5-2.3 times higher than the C cr animals examine-out ratio. The radio-immunoassay of β 2 -M and THP is a better measure for discovering light kidney function injury in early period than C cr method. The clinical value of the radio-immunoassay of β 2 -M, THP is obviously better than the traditional and classical method. The diseases of anybody system may influence the kidney function through various mechanisms. The retrogression of kidney tissue of the patients in old-and mid-age leads to decrease of kidney function. The combination of β 2 -M and THP has the highest anomalous examine-out ratios of kidney function; the next is urine Alb

Radioimmunoassay method for determination of 3, 3', 5'-triiodothyronine (reverse - T3)

International Nuclear Information System (INIS)

Kosowicz, J.

1979-01-01

To introduce radioimmunoassay, 3, 3', 5'-triiodothyronine (reverse-T 3 ) was coupled to bovine serum albumin by the carbodiimide technique and rabbits were immunized with the conjugates obtained. The immunizations were performed by multiple site intradermal injections at places in which cornynebacterium parvum was previously injected to enhance immunologic reaction. After 3 months the rabbits raised antisera to reverse-T 3 of a high titer and specificity. To obtain labelled 125 I-reverse T 3 , 3,3'-diiodothyronine was used. Iodination was performed by the chloramine T technique and the iodination mixture was subjected to gel filtration on Sephadex G-25 (fine) column. The purified monolabelled 125 I-reverse T 3 had a specific activity of 3,000 milli Curie/mg. The reverse T 3 radioimmunoassay of a high sensitivity (ca 2 pg/tube) was introduced in the clinical studies and facilitated direct determination of reverse T 3 in sera without the need of plasma extractions. The interference of serum proteins (TBG) was avoided by adding 8-anilino-1-naphtalene sulfonic acid to serum samples. Separation of free from antibody bound antigens was achieved by polyethylene glycol precipitation or immunoprecipitation. (author)

Circulating Dopamine and C-Peptide Levels in Fasting Nondiabetic Hypertensive Patients

OpenAIRE

Tomaschitz, Andreas; Ritz, Eberhard; Kienreich, Katharina; Pieske, Burkert; M?rz, Winfried; Boehm, Bernhard O.; Drechsler, Christiane; Meinitzer, Andreas; Pilz, Stefan

2012-01-01

OBJECTIVE Accumulating evidence supports a potential role for dopamine in the regulation of insulin secretion. We examined the association between circulating dopamine and C-peptide concentrations using data from the Graz Endocrine Causes of Hypertension (GECOH) study. RESEARCH DESIGN AND METHODS After 12 h of fasting, we measured plasma dopamine and serum C-peptide levels and established determining factors of insulin secretion in 201 nondiabetic hypertensive patients (mean age 48.1 ? 16.0 y...

A high-throughput mass spectrometry assay to simultaneously measure intact insulin and C-peptide.

Science.gov (United States)

Taylor, Steven W; Clarke, Nigel J; Chen, Zhaohui; McPhaul, Michael J

2016-04-01

Measurements of fasting levels of insulin and C-peptide are useful in documenting insulin resistance and may help predict development of diabetes mellitus. However, the specific insulin and C-peptide levels associated with specific degrees of insulin resistance have not been defined, owing to marked variability among immunoassays and lack of standardization. Herein, we describe a multiplexed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for intact insulin and C-peptide. Insulin and C-peptide were enriched from patient sera using monoclonal antibodies immobilized on magnetic beads and processed on a robotic liquid handler. Eluted peptides were analyzed by LC-MS/MS. Bovine insulin and a stable isotopically-labeled (13C/15N) C-peptide were utilized as internal standards. The assay had an analytical measurement range of 3 to 320 μIU/ml (18 to 1920 pmol/l) for insulin and 0.11 to 27.2 ng/ml (36 to 9006 pmol/l) for C-peptide. Intra- and inter-day assay variation was less than 11% for both peptides. Of the 5 insulin analogs commonly prescribed to treat diabetes, only the recombinant drug insulin lispro caused significant interference for the determination of endogenous insulin. There were no observed interferences for C-peptide. We developed and validated a high-throughput, quantitative, multiplexed LC-MS/MS assay for intact insulin and C-peptide. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of carbofuran in water by radioimmunoassay

International Nuclear Information System (INIS)

Zhu Guonian; Wu Huiming; Yang Ting; Hu Xiuqing

2004-01-01

A competitive radioimmunoassay (RIA) method was established to detect carbofuran in water samples. Compared with traditional analytical methods RIA provided a easy procedure with higher sensitivity. The detective limitation of RIA for carbofuran was proved to be 0.175 ng/ml. A study was performed to test validation of the RIA. In this study carbofuran residues in water samples were detected simultaneously by RIA and by high performance liquid chromatograph (HPLC). The linear correlation coefficient of the test results was measure to be 0.9985. (authors)

Alpha-amidated peptides derived from pro-opiomelanocortin in human pituitary tumours

DEFF Research Database (Denmark)

Fenger, M; Johnsen, A H

1988-01-01

Human pituitary tumours, obtained at surgery for Cushing's disease and Nelson's syndrome, were extracted and the content and molecular forms of pro-opiomelanocortin (POMC)-derived peptides determined by radioimmunoassay, gel chromatography, reversed-phase high-performance liquid chromatography....... In conclusion, all the molecular forms of the amidated peptides detected in tumours from patients with Cushing's disease and Nelson's syndrome were similar to the molecular forms found in the normal human pituitary. The main difference between the tumours and the normal pituitary was the greater amount...... (HPLC) and sequence analysis. In the tumours from patients with Cushing's disease the mean concentrations of amidated peptides relative to the total amount of POMC were as follows: alpha-MSH, 1.7%; amidated gamma-MSH (gamma 1-MSH), 8.5% and the peptide linking gamma-MSH and ACTH in the precursor (hinge...

A Study of the Insulin and the C-Peptide Responses to Oral Glucose Load in Nondiabetic and Diabetic Subjects

International Nuclear Information System (INIS)

Lee, Myung Chul; Choi, Sung Jae; Kim, Eung Jin; Koh, Chang Soon; Min, Hun Ki

1977-01-01

The present study was undertaken to evaluate the significance of the insulin and the C-peptide response to oral glucose loads in normal and diabetic subjects and to establish the effects of the obesity. In this study, the authors have measured plasma insulin and C-peptide by means of radioimmunoassay in 10 nonobese normal, 5 obese normal, 13 nonobese moderate diabetic patients, 9 obese moderate diabetic patients and 9 severe diabetic patients. The results obtained were as follows; 1) In 10 nonobese normal subjects, the plasma insulin level at fasting state and at 30, 60, 90, and 120 min after oral glucose loads were 15.7±3.4, 48.3±9.8, 40.4±6.7, 37.4±6.5 and 26.0±4.2 uU/ml (Mean±S.E.) and C-peptide were 1.9±0.3, 3.9±0.6, 6.3±0.6, 5.7±0.5 and 4.0±0.5 ng/ml. The change of C-peptide was found to go almost parallel with that of insulin and the insulin value reaches to the highest level at 30 min whereas C-peptide reaches to its peak at 60 min.. 2) The plasma insulin level in 5 obese normal subjects were 38.9±12.3, 59.5±12.3, 59.2±17.1, 56.1±20.0 and 48.4±17.2 uU/ml and the C-peptide were 5.5±0.4, 6.8±0.5, 7.9±0.8, 7.9±0.8 and 7.8±2.0 ng/ml. The insulin response appeared to be greater than nonobese normal subjects. 3) In 13 nonobese moderate diabetic patients, the plasma insulin levels were 27.1±4.9, 44.1±6.0, 37.3±6.6, 35.5±8.1 and 34.7±10.7 uU/ml and the C-peptide levels were 2.7±0.4, 4.9±0.7, 6.5±0.5, 7.0±0.3 and 6.7±1.0 ng/ml. There was little significance compared to nonobese normal groups but delayed pattern is noted. 4) In 9 obese moderated diabetic patients, the plasma insulin levels were 22.1±7.9, 80.0±19.3, 108.0±27.0, 62.0±17.6 and 55.5±10.l uU/ml and the C-peptide levels were 5.2±0.4, 8.0±1.0, 10.4±1.6, 10.4±1.7 and 10.1±1.0 ng/ml and its response was also greater than that of nonobese moderate diabetic patients. 5) The plasma insulin concentrations in 9 severe diabetic subjects were 8.0±3.8, 12.1±3.5, 16.8±4.6, 19

The Principle and the Method of the Radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Kurata, Kunio [Dainabot Radioisotope Laboratory, Tokyo (Japan)

1970-03-15

The measurements of the amounts of various hormones in the body is one of the most important subjects in the field of endocrinology. The result obtained is not only helpful for the basic studies, such as the function studies of each organ or their interrelationship, but also valuable for routine clinical diagnosis. For the most of peptide hormones or protein hormones, a chemical measurement is very difficult. Biological methods are mostly utilized for this purpose but are not always satisfactory. The use of labeled hormone in combination with its antiserum led to the highly specific and sensitive measurement of the hormone in human plasma. This method is based essentially on the principle of isotope dilution method and is called radioimmunoassay. From the nuclear medical aspect, this is now one of the major fields of in vitro assay with radioisotope. With this method, less than 1 micro unit of insulin per ml of serum can be detected. In this lecture, I would like to talk about the principle and the method of the radioimmunoassay.

Identification of pro-opiomelanocortin and secretion of its peptide fragments in bovine adrenals

Energy Technology Data Exchange (ETDEWEB)

Tennov, A.V.; Dmitriev, A.D.; Kizim, E.A.; Ustinova, E.E.

1986-01-01

This paper describes the results of an investigation to show that biosynthesis of POMC, its proteolytic processing, an secretion of the peptide products of that processing take place in the bovine adrenals. Rabbit antisera against endorphins were obtained and used for radioimmunoassay of peptides. I 125-labeled peptides were obtained by the chloramine method and purified from free I 125 on Sephadex G-10 (0.7 x 5 cm, centrifugation for 10 min at 1500 g). To detect secretion of peptide fragments of POMC in the adrenals experiments were undertaken to determine the beta-endorphin content in perfusates obtained during retrograde perfusion of the bovine adrenals. It was found that immunoreactive compounds, indistinguishable in their immunochemical properties from beta-endorphin, are present in the perfusates, just as in the tissue extracts.

Ovulation following gonadotrophin treatment and determination of serum estradiol and progesterone by radioimmunoassay

International Nuclear Information System (INIS)

Vesper, B.; Lisse, K.; Ittrich, G.

1979-01-01

The use of gonadotrophins to release ovulation is indicated in women with urgent desire for children and with negative response to clomiphene therapy. 69 patients treated with 100 therapeutic gonadotrophin series were examined. Estrogens and progesterone were determined by radioimmunoassay. The treatment resulted in ovulation in 54 women, 12 patients developed an ovarian reaction with an increase of estrogen, and in 34 cases no ovarian response was detectable. 6 women became pregnant during gonadotrophin therapy and further 2 after treatment

Epimerization-free C-terminal peptide activation, elongation and cyclization

NARCIS (Netherlands)

Popović, S.

2015-01-01

C-terminal peptide activation and cyclization reactions are generally accompanied with epimerization (partial loss of C‐terminal stereointegrity). Therefore, the focus of this thesis was to develop epimerization-free methods for C-terminal peptide activation to enable C-terminal peptide elongation

Preparation of Double Antibody Radioimmunoassay for Determination of Alpha fetoprotein as a Tumor Marker using BALB/C Mice as Host Animals

International Nuclear Information System (INIS)

Abdel-Ghany, I.Y.; EI- Mouhty, N.R.A.; Shafil, H.M.; Mehany, N.L.

2009-01-01

The aim of the present work was to prepare liquid phase radioimmunoassay system (RIA) reagents. Development as well as optimization and validation of this RIA system for the measurement of alpha fetoprotein (AFP) in human serum are described. The production of polyclonal antibodies was carried out by immunizing four BALB/C mice subcutaneously. The preparation of 125 I-AFP tracer was performed using chloramine-T oxidation method. The preparation of AFP standards was done by diluting cord sera using assay buffer. The results obtained provide a highly sensitive,precise and accurate RIA system of AFP based on liquid phase separation. In conclusion, this assay could be used for the diagnosis and management of patients with certain malignant diseases and in prenatal diagnosis of neural tube defects

Solid phase radioimmunoassays for human C-reactive protein

International Nuclear Information System (INIS)

Shine, B.; Beer, F.C. de; Pepys, M.B.

1981-01-01

Two new, rapid and sensitive radioimmunoassays for human C-reactive protein (CRP) have been established using antiserum coupled to magnetizable cellulose particles, which facilitate phase separation. A single antibody method, using solid phase anti-CRP, provides a sensitivity of 50 μg/l with a 1-h incubation time and intra- and inter-assay coefficients of variation of 10%. A double antibody method, using fluid phase rabbit anti-CRP serum and solid phase sheep anti-rabbit IgG serum, provides a sensitivity of 3 μg/l with an overnight incubation and intra- and inter-assay coefficients of variation of 10%. Among 468 sera from normal adult volunteer blood donors the median CRP concentration was 800 μg/l, interquartile range 340-1700 μg/l and range 70-29,000 μg/l. Ninety percent of samples contained less than 3 mg/l and 99% less than 10 mg/l. Low levels (14-650 μg/l) of CRP were detected both in amniotic fluids and in cerebrospinal fluids. (Auth.)

Kinetics of circulating endogenous insulin, C-peptide, and proinsulin in fasting nondiabetic man

DEFF Research Database (Denmark)

Henriksen, Jens Henrik Sahl; Tronier, B; Bülow, J B

1987-01-01

Plasma concentrations of insulin, C-peptide, and proinsulin were measured in different vascular beds in order to determine renal, hepatic, and systemic kinetics of the endogenous peptides in the fasting condition. Nineteen nondiabetic subjects were studied, two were normal, nine had minor vascular...

Immunological half-life of porcine proinsulin C-peptide

Energy Technology Data Exchange (ETDEWEB)

Oyama, H; Horino, M; Matsumura, S [Kawasaki Medical Coll., Kurashiki (Japan). Div. of Endocrinology; Kobayshi, K; Suetsugu, N [Yamaguchi Univ., Ube (Japan). School of Medicine

1975-11-01

Immunological half-lifes of injected porcine C-peptide and insulin with RIA were studied and calculated as 9.8 and 8.0 minutes. Higher circulating levels of C-peptide as compared to insulin in normal young swines lead to speculation about a longer half-life of C-peptide. This hypothesis was verified in this study. Immunological half-lifes of porcine proinsulin and insulin in the pig were 20 and 6 minutes, respectively.

Development of SI-traceable C-peptide certified reference material NMIJ CRM 6901-a using isotope-dilution mass spectrometry-based amino acid analyses.

Science.gov (United States)

Kinumi, Tomoya; Goto, Mari; Eyama, Sakae; Kato, Megumi; Kasama, Takeshi; Takatsu, Akiko

2012-07-01

A certified reference material (CRM) is a higher-order calibration material used to enable a traceable analysis. This paper describes the development of a C-peptide CRM (NMIJ CRM 6901-a) by the National Metrology Institute of Japan using two independent methods for amino acid analysis based on isotope-dilution mass spectrometry. C-peptide is a 31-mer peptide that is utilized for the evaluation of β-cell function in the pancreas in clinical testing. This CRM is a lyophilized synthetic peptide having the human C-peptide sequence, and contains deamidated and pyroglutamylated forms of C-peptide. By adding water (1.00 ± 0.01) g into the vial containing the CRM, the C-peptide solution in 10 mM phosphate buffer saline (pH 6.6) is reconstituted. We assigned two certified values that represent the concentrations of total C-peptide (mixture of C-peptide, deamidated C-peptide, and pyroglutamylated C-peptide) and C-peptide. The certified concentration of total C-peptide was determined by two amino acid analyses using pre-column derivatization liquid chromatography-mass spectrometry and hydrophilic chromatography-mass spectrometry following acid hydrolysis. The certified concentration of C-peptide was determined by multiplying the concentration of total C-peptide by the ratio of the relative area of C-peptide to that of the total C-peptide measured by liquid chromatography. The certified value of C-peptide (80.7 ± 5.0) mg/L represents the concentration of the specific entity of C-peptide; on the other hand, the certified value of total C-peptide, (81.7 ± 5.1) mg/L can be used for analyses that does not differentiate deamidated and pyroglutamylated C-peptide from C-peptide itself, such as amino acid analyses and immunochemical assays.

Haloperidol plasmatic levels and their clinical response to the treatment. Comparison between the radioimmunoassay and radioreceptorassay: preliminary data

Energy Technology Data Exchange (ETDEWEB)

Cabranes, J A; Almoguera, I; Santos, J L; Prieto, P; Ramos, J A

1988-06-01

Schizophrenic patients were treated with haloperidol. Their haloperidol levels in plasma were determined with radioimmunoassay (RIA) and radioreceptor assay (RRA). The results obtained are compared with the clinical improvement. (M.C.B.).

Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity; Desenvolvimento e padronizacao da tecnica de radioimunoensaio para a determinacao de pro-insulina humana e sua aplicacao no estudo do diabetes mellitus tipo II associado a obesidade

Energy Technology Data Exchange (ETDEWEB)

Nascimento, Martha do

1996-12-31

The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of {beta} cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author) 133 refs., 17 figs., 36 tabs.

Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity; Desenvolvimento e padronizacao da tecnica de radioimunoensaio para a determinacao de pro-insulina humana e sua aplicacao no estudo do diabetes mellitus tipo II associado a obesidade

Energy Technology Data Exchange (ETDEWEB)

Nascimento, Martha do

1997-12-31

The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of {beta} cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author) 133 refs., 17 figs., 36 tabs.

Prenatal sex determination by radioimmunoassay of testosterone with and without chromatography of the amniotic fluid

International Nuclear Information System (INIS)

Distler, W.; Boniver-Ollmann, U.; Tigges, J.; Terinde, R.; Claussen, U.

1979-01-01

Amniotic fluid testosterone measured by radioimmunoassay (RIA) without chromatography (immunoreactive testosterone) seems not to be a definitive test for prenatal sex determination in all cases. In this study testosterone (T) levels measured by RIA with chromatography of the amniotic fluid samples were compared with immunoreactive testosterone (iT) values, to determine the predictive accuracy of the two methods. In 111 amniotic fluid samples between 15 and 19 weeks of gestation iT and T were measured parallelly. There are significant differences between iT- and T-means of both sexes (p [de

Radioimmunoassay determination of urinary prostaglandins in patients with progressive systemic sclerosis

International Nuclear Information System (INIS)

Ramirez P, P.; Erbessd, M.L.; Mares, G.; Recinos, G.; Graef S, A.; Lavalle, C.

1985-01-01

The results of urinary determinations of E-2 prostaglandines by radioimmunoassay (RIA) in 24-hour urine are presented for three groups: progressive systemic sclerotic patients with normotension and with elevated or normal APR, progressive systemic sclerotic patients with hypertension and with normal or low APR, control group of normal subjects. In a recent report of progressive systemic sclerosis in patients we demonstrated changes in the urine concentratrion of APR levels, sodium excretion and in total blood volume. Based on these findings we felt the need to perform quantifications of E-2 prostaglandines (PGE-2) in 24-hour recently taken urine samples stored at 70 0 and measure the sodium amounts excreted in the urine. We concluded that urinary determination of E-2 prostaglandines was the most suitable for our study as it allowed the establishment of relationships between APR, aldosterone and metabolic sodium balance. (author)

Radioimmunoassay of cholecystokinin in human tissue and plasma

International Nuclear Information System (INIS)

Jansen, J.B.M.J.; Lamers, C.B.H.W.

1983-01-01

A highly sensitive radioimmunoassay for cholecystokinin (CCK) without any cross-reactivity with gastrin is described. The antibody was raised in a rabbit by immunisation with 30% CCK and bound to all COOH-terminal CCK-peptides containing at least 14 amino acid residues. The affinity constant of the antibody was 59.4 x 10 10 l/mol. CCK 33 conjugated to [ 125 I]hydroxyphenylpropionic acid-succinimide ester was used as label. The binding between label and antibody was inhibited by 50% (ID 50 ) at a concentration of 2.8 pmol/l cholecystokinin 33. The detection limit of the assay was between 0.5 and 1.0 pmol/l plasma. Concentrations of CCK in aqueous acid extracts of human upper small intestine were 36.5 +- 9.8 pmol/g and of human cerebral cortex 28.2 +- 2.5 pmol/g tissue. Plasma samples were extracted in 96% ethanol prior to assay. No advantage was obtained by adding aprotinin to the tubes. When frozen at -20 0 C plasma CCK was stable for at least 6 months. Basal plasma CCK concentrations in 30 normal subjects were very low, 0.9 +- 0.1 pmol/l, range 0.5 to 3.1 pmol/l. Intraduodenal administration of fat induced significant increases in plasma CCK from 1.1 +- 0.1 to 8.2 +- 1.3 pmol/l (p = 0.01). Infusion of exogenous CCK, resulting in plasma CCK levels slightly lower than those measured during administration of fat, induced pancreatic enzyme secretion and gallbladder contraction. The reliability of this radioimmunoassay for measurements of CCK in human plasma was extensively evaluated. (Auth.)

Assessment of the specificity of norethisterone radioimmunoassays

Energy Technology Data Exchange (ETDEWEB)

Bedolla-Tovar, N; Rahman, S A; Cekan, S Z; Diczfalusy, E [Swedish Medical Research Council, Karolinska Hospital, Stockholm

1978-06-01

It is concluded that (1) the significance of cross- reaction studies as well as that of the parallelism test for the assessment of the over-all specificity of the assay is limited, (2) a single chromatography prior to the radioimmunoassay proper improves the assay specificity, but may not be sufficient to remove all interfering compounds, (3) a comparison of the direct and chromatographic assay procedures using several antisera is useful for the selection of the relatively most specific radioimmunoassay procedure. In the present study, this is the technique employing either antiserum C or antiserum D, the latter, however, only after chromatography.

Radioimmunoassay in clinical practice

Energy Technology Data Exchange (ETDEWEB)

Ametov, A S

1982-01-01

A wide application of radioimmunoassay in clinical practice is shown. The main theoretical aspects of radioimmunoassay and the fields of application in clinical practice - endocrinology, oncology, allergology, cardiology, pharmacology, pediatrics, hematology, obstetrics and gynecology, are presented.

Release of peptides from Fibrinogen in vitro and in vivo

International Nuclear Information System (INIS)

Weibel, S.

1986-01-01

The dissertation deals experimentally with the following problem fields: The attempt was made to obtain extremely pure, native peptides from fibrinogen with micropreparation with the help of high-pressure liquid chromatography (HPLC); a HPLC-pure antigen which could be labelled (DAT-FPA) was also to be produced and a HPLC-purified, labelled antigen (J 125 DAT-FPA) for the radioimmunoassay was to be prepared. By applying HPLC-purified FPA-material to immunise rabbits, a highly specific antibody against FPA was obtained, and the radioimmunoassay was decisively improved. Furthermore, a method with a high recovery rate specific for the A-peptides could be found. A procedure was developed which is able to separate the modifications from the plasma from one another and to prove them specifically in ng-quantities. This is the first time that the sensitive method of high-pressure liquid chromatography is used to observe the effects of the snake venom enzymes on fibrinogen over a period of 20 hrs. The kinetics of intravenously administered J 123 DAT-FPA and, in comparison, J 123 FPB β 15-42 in vivo in rabbits with the help of a scintiscanning method, was investigated and the distribution in the organism and the ways of elimination were determined. (orig./MG) [de

Radioimmunoassay of human prostate-specific acid phosphatase in the diagnosis and follow-up of therapy of prostatic cancer

International Nuclear Information System (INIS)

Vihko, P.

1981-01-01

The author describes the development of a radioimmunoassay for the determination of serum prostate-specific acid phosphatase and studies its application to the diagnosis and follow-up of therapy of prostatic carcinoma. (Auth./C.F.)

Correlations between fasting plasma C-peptide, glucagon-stimulated plasma C-peptide, and urinary C-peptide in insulin-treated diabetics

DEFF Research Database (Denmark)

Gjessing, H J; Matzen, L E; Frøland, A

1987-01-01

This study correlated fasting plasma C-peptide (CP), plasma CP 6 min after stimulation with 1 mg glucagon i.v., and the mean of three 24-h urinary excretions of C-peptide (UCP)/creatinine in 132 insulin-treated diabetics. Patients were divided into three groups: group 1, stimulated CP less than 0.......06 nM (n = 51); group 2, stimulated CP 0.06-0.60 nM (n = 48); and group 3, stimulated CP greater than 0.60 nM (n = 33). In all patients fasting CP was closely correlated to stimulated CP (r = .988, P less than .001), whereas the correlations between UCP and both fasting CP (r = .904, P less than .001......) and stimulated CP r = .902, P less than .001) were slightly less pronounced. The associations between UCP and both fasting CP (r = .716, P less than .001) and stimulated CP (r = .731, P less than .001) were modest in group 2, and even more so in group 3 (r = .557, P less than .001 and r = .641, P less than .001...

Mycobacteria attenuate nociceptive responses by formyl peptide receptor triggered opioid peptide release from neutrophils.

Directory of Open Access Journals (Sweden)

Heike L Rittner

2009-04-01

Full Text Available In inflammation, pain is regulated by a balance of pro- and analgesic mediators. Analgesic mediators include opioid peptides which are secreted by neutrophils at the site of inflammation, leading to activation of opioid receptors on peripheral sensory neurons. In humans, local opioids and opioid peptides significantly downregulate postoperative as well as arthritic pain. In rats, inflammatory pain is induced by intraplantar injection of heat inactivated Mycobacterium butyricum, a component of complete Freund's adjuvant. We hypothesized that mycobacterially derived formyl peptide receptor (FPR and/or toll like receptor (TLR agonists could activate neutrophils, leading to opioid peptide release and inhibition of inflammatory pain. In complete Freund's adjuvant-induced inflammation, thermal and mechanical nociceptive thresholds of the paw were quantified (Hargreaves and Randall-Selitto methods, respectively. Withdrawal time to heat was decreased following systemic neutrophil depletion as well as local injection of opioid receptor antagonists or anti-opioid peptide (i.e. Met-enkephalin, beta-endorphin antibodies indicating an increase in pain. In vitro, opioid peptide release from human and rat neutrophils was measured by radioimmunoassay. Met-enkephalin release was triggered by Mycobacterium butyricum and formyl peptides but not by TLR-2 or TLR-4 agonists. Mycobacterium butyricum induced a rise in intracellular calcium as determined by FURA loading and calcium imaging. Opioid peptide release was blocked by intracellular calcium chelation as well as phosphoinositol-3-kinase inhibition. The FPR antagonists Boc-FLFLF and cyclosporine H reduced opioid peptide release in vitro and increased inflammatory pain in vivo while TLR 2/4 did not appear to be involved. In summary, mycobacteria activate FPR on neutrophils, resulting in tonic secretion of opioid peptides from neutrophils and in a decrease in inflammatory pain. Future therapeutic strategies may aim

C-terminal peptide extension via gas-phase ion/ion reactions

Science.gov (United States)

Peng, Zhou; McLuckey, Scott A.

2015-01-01

The formation of peptide bonds is of great importance from both a biological standpoint and in routine organic synthesis. Recent work from our group demonstrated the synthesis of peptides in the gas-phase via ion/ion reactions with sulfo-NHS reagents, which resulted in conjugation of individual amino acids or small peptides to the N-terminus of an existing ‘anchor’ peptide. Here, we demonstrate a complementary approach resulting in the C-terminal extension of peptides. Individual amino acids or short peptides can be prepared as reagents by incorporating gas phase-labile protecting groups to the reactive C-terminus and then converting the N-terminal amino groups to the active ketenimine reagent. Gas-phase ion/ion reactions between the anionic reagents and doubly protonated “anchor” peptide cations results in extension of the “anchor” peptide with new amide bond formation at the C-terminus. We have demonstrated that ion/ion reactions can be used as a fast, controlled, and efficient means for C-terminal peptide extension in the gas phase. PMID:26640400

Radioimmunoassay for hepatitis B core antigen

International Nuclear Information System (INIS)

Sagnelli, E.; Pereira, C.; Triolo, G.; Vernace, S.; Paronetto, F.

1982-01-01

Serum hepatitis B core antigen (HBcAg) is an important marker of hepatitis B virus replication. We describe an easy, sensitive radioimmunoassay for determination of HBcAg in detergent-treated serum pellets containing Dane particles. Components of a commercial kit for anticore determination are used, and HBcAG is measured by competitive inhibition of binding of 125 I-labeled antibodies to HBcAg with HBcAg-coated beads. We assayed for HBcAG in the sera of 49 patients with hepatitis B surface antigen (HBsAg)-positive chronic hepatitis, 50 patients with HBsAg-negative chronic hepatitis, and 30 healthy volunteers. HBcAg was detected in 41% of patients with HBsAg-positive chronic hepatitis but not in patients with HBsAg-negative chronic hepatitis. Hepatitis Be antigen (an antigen closely associated with the core of Dane particles) determined in the same sera by radioimmunoassay, was not detected in 50% of HBcAg-positive sera

PreproVIP-derived peptides in the human female genital tract: expression and biological function

DEFF Research Database (Denmark)

Bredkjoer, H E; Palle, C; Ekblad, E

1997-01-01

The aim of the study was to elucidate the localization, distribution, colocalization and biological effect of preproVIP-derived peptides in the human female genital tract. Radioimmunoassays applying antisera against the five functional domains of the VIP precursor in combination with immunohistoc......The aim of the study was to elucidate the localization, distribution, colocalization and biological effect of preproVIP-derived peptides in the human female genital tract. Radioimmunoassays applying antisera against the five functional domains of the VIP precursor in combination...... with immunohistochemistry were used. The effect of preproVIP 22-79, preproVIP 111-122 and preproVIP 156-170 on genital smooth muscle activity in the Fallopian tube was investigated in vitro and compared to that of VIP. All the preproVIP-derived peptides were expressed throughout the genital tract in neuronal elements...

Pathological consequences of C-peptide deficiency ininsulin-dependent diabetes mellitus

Institute of Scientific and Technical Information of China (English)

Ahmad Ghorbani; Reza Shafiee-Nick

2015-01-01

Diabetes is associated with several complicationssuch as retinopathy, nephropathy, neuropathy andcardiovascular diseases. Currently, insulin is the mainused medication for management of insulin-dependentdiabetes mellitus （type-1 diabetes）. In this metabolicsyndrome, in addition to decrease of endogenous insulin,the plasma level of connecting peptide （C-peptide） is alsoreduced due to beta cell destruction. Studies in the pastdecade have shown that C-peptide is much more than abyproduct of insulin biosynthesis and possess differentbiological activities. Therefore, it may be possible thatC-peptide deficiency be involved, at least in part, in thedevelopment of different complications of diabetes. It hasbeen shown that a small level of remaining C-peptide isassociated with significant metabolic benefit. The purposeof this review is to describe beneficial effects of C-peptidereplacement on pathological features associated withinsulin-dependent diabetes. Also, experimental andclinical findings on the effects of C-peptide on wholebodyglucose utilization, adipose tissue metabolism andtissues blood flow are summarized and discussed. Thehypoglycemic, antilipolytic and vasodilator effects ofC-peptide suggest that it may contribute to fine-tuningof the tissues metabolism under different physiologic orpathologic conditions. Therefore, C-peptide replacementtogether with the classic insulin therapy may prevent,retard, or ameliorate diabetic complications in patientswith type-1 diabetes.

Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

International Nuclear Information System (INIS)

Hoffmann, B.

1983-01-01

Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10 -11 M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced. (author)

Describing the Peptide Binding Specificity of HLA-C

DEFF Research Database (Denmark)

Rasmussen, Michael; Harndahl, Mikkel Nors; Nielsen, Morten

for 5 HLA-C molecules and for all, but one, molecule we find a high frequency of binders, >70%, among these peptides. To extend the examined peptide space, we use bioinformatic prediction tools to search for additional binders. Finally, we update our prediction tool, NetMHCpan, with the HLA-C affinity......Human leukocyte antigen (HLA) presents peptides to T-cells for immune scrutiny. Whereas HLA-A and -B have been described in great detail, HLA-C has received much less attention. Here, to increase the coverage of HLA-C and the accuracy of the corresponding tools, we have generated HLA-C molecules...... data and show that the predictive performance for HLA-C molecules now is increased to a level comparable withthat of HLA-A and -B. These novel HLA-C molecules and predictors are successfully used to generate HLA-C tetramers and validate HLA-C-restricted T cell responses....

Results of the HPL determination using a new enzymatic immunoassay - comparison with a commercial radioimmunoassay

International Nuclear Information System (INIS)

Leis, D.; Schneider, B.; Keller, A.; Braun, S.

1982-01-01

An enzymatic immunoassay recently developed by the firm Organon, Oss, Netherlands, to determine HPL in the serum of pregnant women was compared to a widely used radioimmunoassay marketed by the firm Amersham-Buchler, Braunschweig. The values determined showed a good correlation. The accuracy of measurement was within the generally accepted range for immunological assays of this kind. The assay procedures are comparable with regard to the expenditure of time and work. A great advantage of the EIA is due to the absence of radioactive substances, which permits this test to be performed in any laboratory equipped with a centrifuge and photometer. (orig.) [de

Normal levels of plasma FSH and LH in the menstrual cycle as determined by radioimmunoassay

International Nuclear Information System (INIS)

Lemgruber, I.; Pinto, J.C.M.; Linhares, E.; Granafer, A.

1981-01-01

The biological methods were not able to establish adequately the separate determination of FSH and LH. The introduction of radioimmunoassay had allowed the identification of plasma FSH and LH for the purpose of routine clinical use. The utilization of commercial kits, however, obliges each laboratory to have normal levels of his own. Such is the finality of this work, studying samples from 200 normal women, hospitalized for surgical reasons and having not any endocrinological problem. (author) [pt

Ultrasensitive radioimmunoassay for direct determination of free triiodothyronine concentration in serum

International Nuclear Information System (INIS)

Weeke, J.; Oerskov, H.

1975-01-01

Free triiodothyronine (T 3 ) in serum has been measured directly in dialysates of serum, using a wick chromatographic radioimmunoassay. Adequate sensitivity was attained by the use of [ 125 I]T 3 with a very high specific activity (2,000 to 3,000μCi/μg). Sera were dialysed against a Krebs-Ringer bicarbonate buffer modified so as to be similar to plasma water. Dialysis took place under carefully controlled circumstances. The influence on the equilibrium of total to free T 3 of temperature, serum dilution and dialysis time was studied. By the present method, free T 3 in serum from groups of subjects including 20 men, 10 women taking oral contraceptives and 20 women with normal menstrual cycles were identical, averaging 5.2 pg/ml. A chromatographic radioimmunoassay of total T 3 using high specific activity [ 125 I]T 3 and a very small test sample is also described. (auth.)

Determination of the range of control limits in radioimmunoassay measurements

International Nuclear Information System (INIS)

Fiori, A.M.C.

1981-01-01

A grouping technique is proposed for control limits in radioimmunoassay measurements. It has the advantage of working with control limits of 99.7% without the inconvenience of the confidence intervals. The method is practical and simple. It provides considerable flexibility for the processing of data. As the number of samples increases, the control limits become better defined. (author) [es

A sensitive radioimmunoassay for fentanyl

International Nuclear Information System (INIS)

Michiels, M.; Hendriks, R.; Heykants, J.

1977-01-01

Antiserum to fentanyl was obtained in rabbits repeatedly injected with carboxyfentanyl conjugated to bovine serum albumin. Using the antiserum, a highly sensitive radioimmunoassay has been developed, based on the dextran-coated charcoal method. It proved possible to assay the drug directly in plasma, in amounts as small as 30 picogram in 0.5 ml. The antibody was highly specific for fentanyl and no cross-reaction was observed with its major metabolites. This sensitive and specific radioimmunoassay method was employed to determine fentanyl in plasma from six volunteers after an intravenous bolus of 0.2 mg, and in plasma from dogs treated both intravenously and subcutaneously with 0.02 mg/kg. The plasma level of fentanyl could be followed for up to 6 h after a therapeutic dose in dogs and man. (orig.) [de

Measurement of antibodies to tubulin by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Mead, G M; Cowin, P; Whitehouse, J M.A. [CRC Medical Oncology Unit, Southampton General Hospital, Southampton, U.K.

1979-07-24

A solid-phase double antibody radioimmunoassay capable of measuring antibody to tubulin, the principal component of microtubules, is described. This assay is simple, combining sensitivity with specificity and also allowing determination of antibody subclasses.

Present status and future possibilities of radioimmunoassay in animal production

International Nuclear Information System (INIS)

Karg, H.; Claus, R.; Hoffmann, B.; Schallenberger, E.; Schams, D.

1976-01-01

Radioimmunoassays and related isotope techniques have provided new possibilities in hormone analysis. Because of the new dimensions of sensitivity (nanogram and picogram range) it became possible to elucidate for many hormones their levels in peripheral blood plasma. Since some steps of the assay procedures could be automatized, and the evaluation computerized, the efficiency (for example, it is possible to run several thousand determinations weekly in one laboratory) can hardly be equalled by non-isotopic hormone analysis techniques. In animal husbandry the technique can be applied to mapping of physiological phenomena, diagnostic approaches in clinics, control of bio-techniques, residue studies of exogenous hormones, and attempts to use hormonal parameters as guide lines in connection with breeding programmes. The discovery that progesterone levels in milk reflect the corpus luteum function introduced far-reaching radioimmunoassay (RIA) application for fertility control under field conditions. With some other hormones, results of single determinations only allow limited interpretation because of different dynamics, for example releasing pattern, short-term (episodic, diurnal) and long-term (seasonal) variations and clearance properties. Furthermore, questions concerning the interactions between the actual plasma level of the hormone determined and the receptor sites in the target organ have to be solved. There are still gaps concerning the development of radioimmunoassays for important hormones. At present and in the foreseeable future of endocrinology in animal production, radioimmunoassays are indispensible. (author)

Upregulation of α7 Nicotinic Receptors by Acetylcholinesterase C-Terminal Peptides

Science.gov (United States)

Bond, Cherie E.; Zimmermann, Martina; Greenfield, Susan A.

2009-01-01

Background The alpha-7 nicotinic acetylcholine receptor (α7-nAChR) is well known as a potent calcium ionophore that, in the brain, has been implicated in excitotoxicity and hence in the underlying mechanisms of neurodegenerative disorders such as Alzheimer's disease. Previous research implied that the activity of this receptor may be modified by exposure to a peptide fragment derived from the C-terminal region of the enzyme acetylcholinesterase. This investigation was undertaken to determine if the functional changes observed could be attributed to peptide binding interaction with the α7-nAChR, or peptide modulation of receptor expression. Methodology/Principal Findings This study provides evidence that two peptides derived from the C-terminus of acetylcholinesterase, not only selectively displace specific bungarotoxin binding at the α7-nAChR, but also alter receptor binding properties for its familiar ligands, including the alternative endogenous agonist choline. Of more long-term significance, these peptides also induce upregulation of α7-nAChR mRNA and protein expression, as well as enhancing receptor trafficking to the plasma membrane. Conclusions/Significance The results reported here demonstrate a hitherto unknown relationship between the α7-nAChR and the non-enzymatic functions of acetylcholinesterase, mediated independently by its C-terminal domain. Such an interaction may prove valuable as a pharmacological tool, prompting new approaches for understanding, and combating, the process of neurodegeneration. PMID:19287501

Arg-Phe-amide-like peptides in the primitive nervous systems of coelenterates

DEFF Research Database (Denmark)

Grimmelikhuijzen, C J; Ebbesen, Ditte Graff

1985-01-01

By using immunocytochemistry and radioimmunoassays, several substances resembling vertebrate or invertebrate neuropeptides have been found in the nervous systems of coelenterates. The most abundant neuropeptides were those related to the molluscan neuropeptide Phe-Met-Arg-Phe-amide (FMRFamide......). Of antisera against different fragments of FMRFamide, those against RFamide were superior in recognizing the coelenterate peptide. Incubation of whole mounts with these RFamide antisera visualized the coelenterate nervous system in such a detail as has previously not been possible. By using a radioimmunoassay...

Solid phase tube radioimmunoassay for digoxin detection

International Nuclear Information System (INIS)

Stellner, K.; Glatz, C.; Linke, R.

1975-01-01

A solid phase radioimmunoassay with 125 I is described for cardiac patients. The test for the digoxin determination and the poisoning due to cardiac glycosides can be measured very accurately and carried out easily. In addition, the test determination can be automatically performed in connection with other tests. (GSE/LH) [de

Using 1H and 13C NMR chemical shifts to determine cyclic peptide conformations: a combined molecular dynamics and quantum mechanics approach.

Science.gov (United States)

Nguyen, Q Nhu N; Schwochert, Joshua; Tantillo, Dean J; Lokey, R Scott

2018-05-10

Solving conformations of cyclic peptides can provide insight into structure-activity and structure-property relationships, which can help in the design of compounds with improved bioactivity and/or ADME characteristics. The most common approaches for determining the structures of cyclic peptides are based on NMR-derived distance restraints obtained from NOESY or ROESY cross-peak intensities, and 3J-based dihedral restraints using the Karplus relationship. Unfortunately, these observables are often too weak, sparse, or degenerate to provide unequivocal, high-confidence solution structures, prompting us to investigate an alternative approach that relies only on 1H and 13C chemical shifts as experimental observables. This method, which we call conformational analysis from NMR and density-functional prediction of low-energy ensembles (CANDLE), uses molecular dynamics (MD) simulations to generate conformer families and density functional theory (DFT) calculations to predict their 1H and 13C chemical shifts. Iterative conformer searches and DFT energy calculations on a cyclic peptide-peptoid hybrid yielded Boltzmann ensembles whose predicted chemical shifts matched the experimental values better than any single conformer. For these compounds, CANDLE outperformed the classic NOE- and 3J-coupling-based approach by disambiguating similar β-turn types and also enabled the structural elucidation of the minor conformer. Through the use of chemical shifts, in conjunction with DFT and MD calculations, CANDLE can help illuminate conformational ensembles of cyclic peptides in solution.

Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, B. (Institut fuer Veterinaermedizin des Bundesgesundheitsamtes (Robert von Ostertag-Institut), Berlin (Germany, F.R.))

1983-07-01

Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10/sup -11/ M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced.

Radioimmunoassay of thyrotropin releasing hormone in plasma and urine

International Nuclear Information System (INIS)

Saito, Shiro; Musa, Kimitaka; Yamamoto, Suzuyo; Oshima, Ichiyo; Funato, Toyohiko

1975-01-01

A sensitive and specific radioimmunoassay has been developed capable of measuring thyrotropin releasing hormone (TRH) in extracted human plasma and urine. All of three TRH analogues tested had little cross-reactivity to antibody. Luteinizing hormone releasing hormone, lysine vasopressin, rat growth hormone and bovine albumin were without effect, but rat hypothalamic extract produced a displacement curve which was parallel to that obtained with the synthetic TRH. Sensitivity of the radioimmunoassay was 4 pg per tube with intraassay coefficient of variation of 6.2-9.7%. Synthetic TRH could be quantitatively extracted by methanol when added to human plasma in concentration of 25, 50 and 100 pg/ml. TRH immunoreactivity was rapidly reduced in plasma at 20 0 C than at 0 0 C, but addition of peptidase inhibitors, FOY-007 and BAL, prevented the inactivation of TRH for 3 hr at 0 0 C. The TRH in urine was more stable at 0 0 C than 20 0 C, and recovered 75+-4.6% at 24 hr after being added. The plasma levels of TRH were 19 pg/ml or less in normal adults and no sex difference was observed. The rate of disappearance of TRH administered i.v. from the blood could be represented as half-times of 4-12 min. Between 5.3-12.3% of the injected dose was excreted into urine within 1 hr as an immunoreactive TRH. These results indicate the usefulness of TRH radioimmunoassay for clinical investigation. (auth.)

Some important concepts in development of radioimmunoassay (RIA) for hormones, viruses and drugs. [Peptide hormones, non-peptide hormones

Energy Technology Data Exchange (ETDEWEB)

Shah, K B; Mani, R S [Bhabha Atomic Research Centre, Bombay (India). Radiopharmaceuticals Section

1981-01-01

Radioimmunoassay (RIA) procedures for the quantitative measurement of polypeptide and steroid hormones and other substances of medical and biological interest constitute one of the most important and rapidly expanding groups of applications of radioactive tracers in analytical chemistry and the life sciences. The method consists in setting up assays wherein the isotopically tagged substance is allowed to compete with its non-radioactive counterpart for the limited binding sites of a specific antibody. The degree of competitive inhibition of binding of labelled tracer is determined by measuring the radioactivity of the bound or unbound (free) complex, and comparing with the corresponding values for standard solutions of known concentration. This paper outlines the salient features, and specific problems associated with the preparation, purification of immunoreactive labelled tracers, and other suitable RIA reagents, the stability and storage conditions and standardisation of assay procedure. The characteristics of the assay systems have been investigated in detail and regular quality control has been instituted for evaluating various statistical parameters, inter-assay and intra-assay variances, and effective shelf life of the RIA reagents, with specific reference to assays of insulin growth hormones and thyroid and pregnancy hormones.

Development of a radioimmunoassay for pig pancreatic kallikrein

Energy Technology Data Exchange (ETDEWEB)

Fink, E; Guettel, C [Muenchen Univ. (Germany, F.R.). Chirurgische Klinik

1978-07-01

A radioimmunoassay for the determination of pig pancreatic kallikrein was developed. The chloramine-T method was employed for the labelling of the antigen with /sup 125/I. The assay allows the determination of kallikrein in concentrations as low as 0.4 ..mu..g/l. Pig urinary and pig submandibular kallikreins are indistinguishable from pig pancreatic kallikrein by the assay. No cross reactivity was observed for bovine trypsin and chymotrypsin, porcine trypsin and kallikreins of guinea pig submandibular glands and guinea pig coagulation glands. Because of the high specificity of the assay, which is not attainable with conventional assays based on the enzymatic activity, the radioimmunoassay is highly suited for investigations into the physiological role and the pharmacological mechanism of action of pig glandular kallikreins.

A newly developed precise and sensitive radioimmunoassay for clonidine

International Nuclear Information System (INIS)

Arndts, D.; Struck, C.J.; Staehle, H.

1979-01-01

A new precise and sensitive radioimmunoassay for clonidine has been developed. Synthesis and analysis of the hapten (4-carboxy-clonidine; St 1984) as well as antibody production in rabbits are described in detail. At a final dilution of 1:1000 the resulting immune serum binds 50% of a tritiated clonidine standard containing 1 ng of clonidine. The detection limit of the presented radioimmunoassay for clonidine is 0.1 ng/ml. The coefficient of variation did not exceed 4.3% for any of 7 standard determinations with 5 replicates. There was no relevant crossreactivity of inactive clonidine metabolites apart from 4-OH-clonidine. To avoid any errors from cross-reaction clonidine was selectively and quantitatively extracted into diethylether from unknown plasma samples. Following concentration of the extracts even such low concentrations as 20 pg of clonidine/ml plasma were detectable. With the radioimmunoassay applied in pharmacokinetic studies a maximal clonidine concentration in blood plams of healthy human volunteers was determined to 0.6 ng/ml 1.5 h after oral administration of 150 μg. (orig.) [de

Promotion of radioimmunoassay in human health

Energy Technology Data Exchange (ETDEWEB)

Dudley, R A [International Atomic Energy Agency, Vienna (Austria). Div. of Life Sciences

1983-06-01

Radioimmunoassay is an analytical technique which makes use of highly specific and sensitive antibodies to segregate particular substances of interest and radioactive tracers to permit quantification of minute amounts. Some procedures use specific biological ''reagents'' other than antibodies and tracers other than radionuclides. Radioimmunoassay plays an enormous role in medical diagnosis and research. Depending on the services to be performed, the radioimmunoassay laboratories are classified into 4 categories. The laboratory of each category is staffed and equipped with facilities according to its scope and quantity of work. From 1980-1982, nearly US $2 million had been used under the Agency's Technical Cooperation Programme for the promotion of radioimmunoassay in human health.

Radioimmunoassay for yeast killer toxin from Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Siddiqui, F.A.; Bussey, H.

1981-01-01

A radioimmunoassay was developed for the K1 killer toxin from strain T158C/S14a of Saccharomyces cerevisiae. Iodine 125-labelled toxin was made to a specific activity of 100 μCi/mg of protein. Antibody to purified toxin was prepared in rabbits using toxin cross-linked to itself. These antibodies, partially purified by 50 percent ammonium sulfate precipitation and Sepharose CL-6B column chromatography, produced one precipitation band with killer toxin and bound 125 I-labelled toxin in a radioimmunoassay. The antibody preparation also bound with the toxins from another K1 killer, A364A, and three chromosomal superkiller mutants derived from it. (auth)

Determination of plasma aldosterone in children by thin layer chromatography and radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Parth, K; Zimprich, H; Brunel, R [The Ludwig Boltzmann Institute of Paediatric Endocrinology; The Karolinen Kinderspital, Vienna)

1976-01-01

An accurate and relatively simple radioimmunoassay for the determination of aldosterone concentration in peripheral plasma has been developed. 0.5-2.0 ml plasma with added ..cap alpha..1.2-/sup 3/H..omega..aldosterone is extracted with dichloromethane. Purification of the extract is achieved by thin layer chromatography in the system benzene-acetone 1:1. Recovery of ..cap alpha..1,2-/sup 3/H..omega..aldosterone is 58+-6 (sd) %. Bound and free fractions are separated by dextran-coated charcol. The intra-assay reproducibility is 8.8 % and the inter-assay reproducibility varies from 11.4-16.1%. The sensitivity of the assay for a 5 ml plasma sample can be put at 0.2 ng/100 ml. Normal values determined in 52 healthy children of different age groups are presented. Furthermore the aldosterone stimulating effect of low sodium diet (17 children), severe and prolonged vomiting (19 children) and synthetic ACTH (10 children) has been studied by our modified method.

Solid-phase peptide quantitation assay using labeled monoclonal antibody and glutaraldehyde fixation

International Nuclear Information System (INIS)

Kasprzyk, P.G.; Cuttitta, F.; Avis, I.; Nakanishi, Y.; Treston, A.; Wong, H.; Walsh, J.H.; Mulshine, J.L.

1988-01-01

A solid-phase radioimmunoassay utilizing iodinated peptide-specific monoclonal antibody as a detection system instead of labeled peptide has been developed. Regional specific monoclonal antibodies to either gastrin-releasing peptide or gastrin were used as models to validate the general application of our modified assay. Conditions for radioactive labeling of the monoclonal antibody were determined to minimize oxidant damage, which compromises the sensitivity of other reported peptide quantitation assays. Pretreatment of 96-well polyvinyl chloride test plates with a 5% glutaraldehyde solution resulted in consistent retention of sufficient target peptide on the solid-phase matrix to allow precise quantitation. This quantitative method is completed within 1 h of peptide solid phasing. Pretreatment of assay plates with glutaraldehyde increased binding of target peptide and maximized antibody binding by optimizing antigen presentation. The hypothesis that glutaraldehyde affects both peptide binding to the plate and orientation of the peptide was confirmed by analysis of several peptide analogs. These studies indicate that peptide binding was mediated through a free amino group leaving the carboxy-terminal portion of the target peptide accessible for antibody binding. It was observed that the length of the peptide also affects the amount of monoclonal antibody that will bind. Under the optimal conditions, results from quantitation of gastrin-releasing peptide in relevant samples agree well with those from previously reported techniques. Thus, we report here a modified microplate assay which may be generally applied for the rapid and sensitive quantitation of peptide hormones

Measurement of serum free thyroxine using fT4(fraction) determined by solidphase radioimmunoassay: First clinical results

International Nuclear Information System (INIS)

Reiners, C.; Walter, H.; Moll, E.; Boerner, W.

1983-01-01

The novel solidphase RIA SPAC ET permits the simultaneous determination of TF 4 , TT 4 and fT 4 -fraction. The duration until the complete results of this assay can be obtained is a little bit less than for parallel radioimmunologic FT 4 - and TT 4 -determinations. The results of our quality control survey indicate that the precision of the precommercial kits tested should be improved. In addition, the normal range of FT 4 from 5.5 pg/ml to 12.5 pg/ml should be adapted in the final assay version of the approximately 30% higher normal ranges which are common with alternative FT 4 -radioimunoassays. In comparison to FT 4 -I, TT 4 /TBG-ratio and other FT 4 -radioimmunoassays, the diagnostic accuracy of FT 4 determined by SPAC ET is equally good. Estrogen-mediated TBG elevations on oral contraceptives are well compensated. In pregnancy, the known tendency towards lower FT 4 levels can be seen with the beginning of the second trimester. While there are no changes of FT 4 levels on medication with acetylosalicyclic acid, a slight tendency towards lower FT 4 determined by SPAC ET can be seen on therapy with phenytoin. Under treatment with heparin, FT 4 by SPAC ET is elevated. This is more reasonable than the decreases of FT 4 concentrations observed with radioimmunoassays using FT 4 analogues as tracers. RIA SPAC ET is an interesting alternative to routinely used direct and indirect methods for determination of free thyroxine. (orig.) [de

Solid phase radioimmunoassays

International Nuclear Information System (INIS)

Wide, L.

1977-01-01

Solid phase coupled antibodies were introduced to facilitate the separation of bound and free labelled ligand in the competitive inhibition radioimmunoassay. Originally, the solid matrix used was in the form of small particles and since then a number of different matrices have been used such as very fine powder particles, gels, paper and plastic discs, magnetic particles and the inside surface of plastic tubes. The coupling of antibodies may be that of a covalent chemical binding, a strong physical adsorbtion, or an immunological binding to a solid phase coupled antigen. New principles of radioimmunoassay such as the solid phase sandwich techniques and the immunoradiometric assay were developped from the use of solid phase coupled antigens and antibodies. The solid phase sandwich techniques are reagent excess methods with a very wide applicability. Several of the different variants of solid phase techniques are suitable for automation. Advantages and disadvantages of solid phase radioimmunoassays when compared with those using soluble reagents are discussed. (orig.) [de

Radioimmunoassay for tetrahydrocortisol

International Nuclear Information System (INIS)

Mougey, E.H.

1978-01-01

A radioimmunoassay for urinary tetrahydrocortisol (THF) is described. Antibodies were produced in rabbits against a THF-monohemisuccinate:bovine serum albumin conjugate. The radioimmunoassay procedure involves enzymic hydrolysis of the urine, extraction with ethyl acetate, radioimmunoassay, and separation of free from bound steroid with Somogyi reagents. The antibody showed some cross-reaction with tetrahydro substance S (36%) which does not occur in urine in appreciable amounts and with tetrahydrocortisone (10%) which does. An analysis of monkey urine extracts before and after tlc purification revealed that the THF antibody was specific enough to permit assay of urines for THF during stress experiments without a purification step. THF values obtained correlated very highly with 17-hydroxycorticosteroid values on the same urines obtained from monkeys during a chair restraint experience (r = 0.97). Also for comparison pruposes these same urines were assayed for free THF, total cortisol, and free cortisol. The free (unconjugated) steroids showed the greatest percentage increase over basal levels

Average concentrations of FSH and LH in seminal plasma as determined by radioimmunoassay

International Nuclear Information System (INIS)

Milbradt, R.; Linzbach, P.; Feller, H.

1979-01-01

In 322 males, 25 to 50 years of age, levels of LH and FSH respectively were determined in seminal plasma by radioimmunoassay. Average values of 0,78 ng/ml and 3,95 ng/ml were found as for FSH and LH respectively. Sperm count and motility were not related to FSH levels, but were to LH levels. A high count of spermatozoa corresponded to high concentration of LH, and normal motility was associated with higher levels of LH as compared to levels associated with asthenozoospermia. With respect to count of spermatozoa of a single or the average patient, it is suggested that the ratio of FSH/LH would be more meaningful than LH level alone. (orig.) [de

Development of radioimmunoassay for pantothenic acid in biological tissues

International Nuclear Information System (INIS)

Wyse, B.W.

1977-01-01

The purpose of this research was to develop a radioimmunoassay for quantitating pantothenic acid levels in biological tissues and to compare the new method with a microbiological procedure. Since pantothenic acid is a nonantigenic compound with a small molecular weight, it was treated as a hapten and conjugated with an immunogenic protein. A new technique for covalently linking haptens with primary alcohol groups to proteins was developed. To prepare an antiserum for the radioimmunoassay, pantothenic acid-bovine serum albumin antigen was injected into the foot pads of rabbits. As antibodies to pantothenic acid hapten were elicited they were characterized using three classical techniques: ring precipitant test, gel diffusion (Ouchterlony), and skin test (Arthus). For the radioimmunoassay an appropriate dilution of antiserum was incubated in the presence of tritium labeled pantothenic acid and non-radioactive pantothenic acid for the standard curve or tissue extracts containing pantothenic acid. After incubation overnight, the antibodies were precipitated and solubilized and the radioactivity was counted in a liquid scintillation counter. Blood pantothenic acid levels of sixty-eight senior citizens were determined by the radioimmunoassay and by microbiological assay with Lactobacillus plantarum. A highly significant correlation was found between the two assays

Fall in C-Peptide During First 2 Years From Diagnosis

Science.gov (United States)

Greenbaum, Carla J.; Beam, Craig A.; Boulware, David; Gitelman, Stephen E.; Gottlieb, Peter A.; Herold, Kevan C.; Lachin, John M.; McGee, Paula; Palmer, Jerry P.; Pescovitz, Mark D.; Krause-Steinrauf, Heidi; Skyler, Jay S.; Sosenko, Jay M.

2012-01-01

Interpretation of clinical trials to alter the decline in β-cell function after diagnosis of type 1 diabetes depends on a robust understanding of the natural history of disease. Combining data from the Type 1 Diabetes TrialNet studies, we describe the natural history of β-cell function from shortly after diagnosis through 2 years post study randomization, assess the degree of variability between patients, and investigate factors that may be related to C-peptide preservation or loss. We found that 93% of individuals have detectable C-peptide 2 years from diagnosis. In 11% of subjects, there was no significant fall from baseline by 2 years. There was a biphasic decline in C-peptide; the C-peptide slope was −0.0245 pmol/mL/month (95% CI −0.0271 to −0.0215) through the first 12 months and −0.0079 (−0.0113 to −0.0050) from 12 to 24 months (P < 0.001). This pattern of fall in C-peptide over time has implications for understanding trial results in which effects of therapy are most pronounced early and raises the possibility that there are time-dependent differences in pathophysiology. The robust data on the C-peptide obtained under clinical trial conditions should be used in planning and interpretation of clinical trials. PMID:22688329

Radioimmunoassay for a human prostate specific antigen

International Nuclear Information System (INIS)

Machida, T.; Miki, M.; Ohishi, Y.; Kido, A.; Morikawa, J.; Ogawa, Y.

1983-01-01

As a marker for prostatic cancer, a prostate-specific antigen was purified from human prostatic tissues. Double antibody radioimmunoassay utilizing immune reaction was developed on the basis of the purified prostatic antigen (PA). Measurement results have revealed that PA radioimmunoassay is much better than prostatic acid phosphatase (PAP) radioimmunoassay in the diagnosis of prostatic cancer

Multiple epitopes in a dodecapeptide of myelin basic protein determined bymonoclonal antibodies

International Nuclear Information System (INIS)

Price, J.O.; Whitaker, J.N.; Vasu, R.I.; Metzger, D.W.

1986-01-01

Three custom synthesized myelin basic protein (MBP) peptides, bovine peptide 79-88, human peptide 80-89, and human peptide 82-91, were used to produce four murine monoclonal antibodies (MAb) that were selected on the basis of reaction in a solid phase radioimmunoassay (SRIA) with human MBP. The MAb were compared with respect to antigen specificity against intact MBP and 10 overlapping MBP peptides. One MAb recognized an epitope near the amino-terminus of bovine MBP peptide 79-88. A second MAb was directed towards an epitope that is more reactive in human MBP peptide 45-89 than in intact MBP, but is not recognized in any of the small MBP peptides examined. The third MAb detected an epitope near the middle of human MBP peptide 80-89, whereas the fourth MAb reacted with the carboxyl-terminal portion of human MBP peptide 82-91. Epitopes recognized in SRIA were sometimes not detected by the same MAb in a fluid phase double antibody radioimmunoassay. These results demonstrate the multiplicity of potential epitopes in a dodecapeptide of MBP and do not support the concept of a single, dominant epitope in the region of MBP peptide 80-89

Solid phase 125I labelled radioimmunoassay for spermidine

International Nuclear Information System (INIS)

Zhao Shimin

1991-01-01

Using 125 I labelled monoclonal antibody against spermidine and solid phase antigen spermidine-bovine serum albumin conjugate, the radioimmunoassay for spermidine was developed. The sensitivity of this method was about 8 times higher than that of liquid phase 14 C labelled spermidine radioimmunoassay, reaching detection limit of 10 ng/ml (0.5 ng/tube). The working range of standard curve was 0-10 5 ng/ml. The new method was suitable for spermidine measurements in saliva, stomach fluid, and cerebrospinal fluid. The coefficients of variation (CV) of within and between-assay were 4% and 13%, respectively. Preliminary clinical measurements showed that the spermidine levels in saliva of cancer patients and in cerebrospinal fluid of leukemia patients were significantly elevated

Anamnesis of the radioimmunoassay: A historical reminiscence

Energy Technology Data Exchange (ETDEWEB)

Kallee, E

1984-01-27

Anamnesis of the Radioimmunoassay - A Historical Reminiscence: Several requirements have to be met before the first radioimmunoassay of a proteohormone (i.e., insulin) could be developed. One of these requirements was that iodination ought not substantially impair the immunologic properties of the insulin molecule. Since the reversibility of antigen adsorption to antibodies is the most important basis of all immunoassays, the adsorptive behavior of proteins first had to be studied at extremely low protein concentrations. Only after these requirements had been investigated was direct electrophoretic detection of a nonprecipitating anti-hormone antibody possible by desorption of insulin on filter paper. Later, the inaccuracy of the species specificity of insulin-binding antibodies proved to be particularly useful for the determination of insulin in human sera.

Radioimmunoassay of measles virus hemagglutinin protein G

International Nuclear Information System (INIS)

Lund, G.A.; Salmi, A.A.

1982-01-01

Guinea pig and rabbit antisera from animals immunized with purified measles virus hemagglutinin (G) protein were used to establish a solid-phase four-layer radioimmunoassay for quantitative measurement of the G protein. The sensitivity of the assay was 2 ng of purified G protein, and 200 μg of protein from uninfected Vero cells neither decreased the sensitivity nor reacted non-specifically in the assay. Radioimmunoassay standard dose-response curves were established and unknown values interpolated from these using the logit program of a desktop computer. Using this procedure, a measles virus growth curve in infected Vero cells was determined by measurement of G protein production. Under these same conditions, hemagglutination was not sensitive enough to detect early hemagglutinin production. Viral antigens in canine distemper virus, Newcastle disease virus, parainfluenza viruses 1-4, simian virus 5, and respiratory syncytial virus-infected cell lysates did not cross-react in the radioimmunoassay. A small degree of cross-reactivity was detected with mumps viral antigens, both with Vero cell-derived (wild-type strain) and egg-derived (Enders strain) purified virus preparations and with a cell lysate antigen prepared from wild-type mumps virus-infected Vero cells. (Auth.)

Radioimmunoassay of measles virus hemagglutinin protein G

Energy Technology Data Exchange (ETDEWEB)

Lund, G A; Salmi, A A [Turku Univ. (Finland)

1982-08-01

Guinea pig and rabbit antisera from animals immunized with purified measles virus hemagglutinin (G) protein were used to establish a solid-phase four-layer radioimmunoassay for quantitative measurement of the G protein. The sensitivity of the assay was 2 ng of purified G protein, and 200 ..mu..g of protein from uninfected Vero cells neither decreased the sensitivity nor reacted non-specifically in the assay. Radioimmunoassay standard dose-response curves were established and unknown values interpolated from these using the logit program of a desktop computer. Using this procedure, a measles virus growth curve in infected Vero cells was determined by measurement of G protein production. Under these same conditions, hemagglutination was not sensitive enough to detect early hemagglutinin production. Viral antigens in canine distemper virus, Newcastle disease virus, parainfluenza viruses 1-4, simian virus 5, and respiratory syncytial virus-infected cell lysates did not cross-react in the radioimmunoassay. A small degree of cross-reactivity was detected with mumps viral antigens, both with Vero cell-derived (wild-type strain) and egg-derived (Enders strain) purified virus preparations and with a cell lysate antigen prepared from wild-type mumps virus-infected Vero cells.

Radioimmunoassay for 6-D-tryptophan analog of luteinizing hormone-releasing hormone: measurement of serum levels after administration of long-acting microcapsule formulations

International Nuclear Information System (INIS)

Mason-Garcia, M.; Vigh, S.; Comaru-Schally, A.M.; Redding, T.W.; Somogyvari-Vigh, A.; Horvath, J.; Schally, A.V.

1985-01-01

A sensitive and specific radioimmunoassay for [6-D-tryptophan]luteinizing hormone-releasing hormone ([D-Trp 6 ]LH-RH) was developed and used for following the rate of liberation of [D-Trp 6 ]LH-RH from a long-acting delivery systems based on a microcapsule formulation. Rabbit antibodies were generated against [D-Trp 6 ]LH-RH conjugated to bovine serum albumin with glutaraldehyde. Crossreactivity with LH-RH was less than 1%; there was no significant cross-reactivity with other peptides. The minimal detectable dose of [D-Trp 6 ]LH-RH was 2 pg per tube. In tra- and interassay coefficients of variation were 8% and 10%, respectively. The radioimmunoassay was suitable for direct determination of [D-Trp 6 ]LH-RH in serum, permitting the study of blood levels of the analog after single injections into normal men and after one-a-month administration of microcapsules to rats. In men, 90 min after subcutaneous injection of 250 μg of the peptide, serum [D-Trp 6 ]LH-RH rose to 6-12 ng/ml. Luteinizing hormone was increased 90 min and 24 hr after the administration of the analog. Several batches of microcapsules were tested in rats and the rate of release of [D-Trp 6 ]LH-RH was followed. The improved batch of microcapsules of [D-Trp 6 ]LH-RH increased serum concentrations of the analog for 30 days or longer after intramuscular injection

Comparative determination of the rheumatic factor by means of agglutination, immunofluorescence and radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Jaeger, L.; Storz, H.; Hein, G.; Schlenvoigt, G. (Friedrich-Schiller-Universitaet, Jena (German Democratic Republic). Bereich Medizin)

1982-01-01

The rheumatic factor (RF) was determined by means of agglutination, immunofluorescence (IF) test and radioimmunoassay (RIPEGA) in random groups of 56 patients with rheumatoid arthritis (RA), 13 patients with seronegative RA and 39 patients with psoriasis arthropathica. All three methods are of equal value with regard to the number of positive results. Further classification of seronegative patients, i.e. patients with a negative agglutination reaction and the clinical symptoms of RA is possible with the IF method and, above all, by means of RIPEGA. But because of the comprehensive test devices the two methods are only an alternative. Titer differences are attributed to the different indication principles and the immunological heterogeneity of RF. An improvement of the diagnosis of activity was not possible.

Comparative determination of the rheumatic factor by means of agglutination, immunofluorescence and radioimmunoassay

International Nuclear Information System (INIS)

Jaeger, L.; Storz, H.; Hein, G.; Schlenvoigt, G.

1982-01-01

The rheumatic factor (RF) was determined by means of agglutination, immunofluorescence (IF) test and radioimmunoassay (RIPEGA) in random groups of 56 patients with rheumatoid arthritis (RA), 13 patients with seronegative RA and 39 patients with psoriasis arthropathica. All three methods are of equal value with regard to the number of positive results. Further classification of seronegative patients, i.e. patients with a negative agglutination reaction and the clinical symptoms of RA is possible with the IF method and, above all, by means of RIPEGA. But because of the comprehensive test devices the two methods are only an alternative. Titer differences are attributed to the different indication principles and the immunological heterogeneity of RF. An improvement of the diagnosis of activity was not possible. (author)

Phosphorylated form of adrenocorticotropin and corticotropin-like intermediary lobe peptide in human tumors

International Nuclear Information System (INIS)

Massias, J.F.; Hardouin, S.; Vieau, D.; Lenne, F.; Bertagna, X.

1994-01-01

Many peptides contribute to the heterogeneity of immunoreactive adrenocorticotropin (ACTH) in man. The use of a radioimmunoassay (RIA) specifically directed against the C-terminal end of ACTH allowed the precise study of the following four peptides: ACTH itself, corticotropin-like intermediary lobe peptide (CLIP) or ACTH and their phosphorylated forms on SeR 31 . The authors have set up a high-performance liquid chromatography system that separates these four molecules in a single run, to establish their relative distributions in tumors responsible for Cushing's disease or for the ectopic ACTH syndrome, and to evaluate the possible interference of phospho-Ser 31 on various RIA or immuno-radiometric assay (IRMA) recognition systems for ACTH. In this system, alkaline phosphatase treatment shifted the retention time of the phosphorylated peptides to that of their non-phosphorylated counterparts. In three tumors responsible for the ectopic ACTH syndrome, CLIP peptides were predominant in two and phosphorylated molecules represented between 22% and 50% of immuno-reactive materials. In five pituitary tumors responsible for Cushing's disease, ACTH peptides were predominant and the phosphorylated molecules varied between 35% and 75% in four of them. In the same tumor the ratios of phosphorylated to non-phosphorylated CLIP or ACTH were identical. The presence of phospho-Ser 31 did not affect the recognition ability of two mid-ACTH and two C-terminal ACTH RIA's, nor of the ACTH IRMA. 15 refs., 5 figs., 2 tabs

The promotion of radioimmunoassay in human health

International Nuclear Information System (INIS)

Dudley, R.A.

1983-01-01

Radioimmunoassay is an analytical technique which makes use of highly specific and sensitive antibodies to segregate particular substances of interest and radioactive tracers to permit quantification of minute amounts. Some procedures use specific biological ''reagents'' other than antibodies and tracers other than radionuclides. Radioimmunoassay plays an enormous role in medical diagnosis and research. Depending on the services to be performed, the radioimmunoassay laboratories are classified into 4 categories. The laboratory of each category is staffed and equipped with facilities according to its scope and quantity of work. From 1980-1982, nearly US$ 2 million had been used under the Agency's Technical Cooperation Programme for the promotion of radioimmunoassay in human health

C-peptide increases Na,K-ATPase expression via PKC- and MAP kinase-dependent activation of transcription factor ZEB in human renal tubular cells.

Directory of Open Access Journals (Sweden)

Dana Galuska

Full Text Available Replacement of proinsulin C-peptide in type 1 diabetes ameliorates nerve and kidney dysfunction, conditions which are associated with a decrease in Na,K-ATPase activity. We determined the molecular mechanism by which long term exposure to C-peptide stimulates Na,K-ATPase expression and activity in primary human renal tubular cells (HRTC in control and hyperglycemic conditions.HRTC were cultured from the outer cortex obtained from patients undergoing elective nephrectomy. Ouabain-sensitive rubidium ((86Rb(+ uptake and Na,K-ATPase activity were determined. Abundance of Na,K-ATPase was determined by Western blotting in intact cells or isolated basolateral membranes (BLM. DNA binding activity was determined by electrical mobility shift assay (EMSA. Culturing of HRTCs for 5 days with 1 nM, but not 10 nM of human C-peptide leads to increase in Na,K-ATPase α(1-subunit protein expression, accompanied with increase in (86Rb(+ uptake, both in normal- and hyperglycemic conditions. Na,K-ATPase α(1-subunit expression and Na,K-ATPase activity were reduced in BLM isolated from cells cultured in presence of high glucose. Exposure to1 nM, but not 10 nM of C-peptide increased PKCε phosphorylation as well as phosphorylation and abundance of nuclear ERK1/2 regardless of glucose concentration. Exposure to 1 nM of C-peptide increased DNA binding activity of transcription factor ZEB (AREB6, concomitant with Na,K-ATPase α(1-subunit mRNA expression. Effects of 1 nM C-peptide on Na,K-ATPase α(1-subunit expression and/or ZEB DNA binding activity in HRTC were abolished by incubation with PKC or MEK1/2 inhibitors and ZEB siRNA silencing.Despite activation of ERK1/2 and PKC by hyperglycemia, a distinct pool of PKCs and ERK1/2 is involved in regulation of Na,K-ATPase expression and activity by C-peptide. Most likely C-peptide stimulates sodium pump expression via activation of ZEB, a transcription factor that has not been previously implicated in C-peptide

Radioimmunoassay for plasma renin activity

International Nuclear Information System (INIS)

1975-01-01

A radioimmunoassay for the determination of renin activity in blood plasma is described. The plasma sample is mixed with a generator buffer solution also containing an inhibitor for enzymes which convert angiotensin I into other substances. The renin in the plasma sample converts angiotensinogen into angiotensin I. The amount of angiotensin I is then measured with a competitive binding method using 125 I-labelled angiotensin I and antibodies to angiotensin I

Radioimmunoassays of papain in beer

International Nuclear Information System (INIS)

Rauch, P.; Fukal, L.; Strejcek, F.; Kas, J.

1984-01-01

A radioimmunoassay (RIA) of papain is described which is capable of detecting 0.2 μg of papain/ml in beer, a level approximately 1% of that normally used for chillproofing. Changes in incubation conditions significantly accelerate the papain determination with only slight loss of accuracy. Apart from the high sensitivity it has been shown that the method is highly specific and distinguishes papain from the other chillproofing enzymes used. (author)

Thyroxine determination in serum by radioimmunoassay and competitive protein-binding analysis (simultaneous study using four test kits)

International Nuclear Information System (INIS)

Wagner, K.

1978-01-01

Three commercial test kits for radioimmunological T 4 -determination have been tested (T 4 -RIA Abbott, RIA-mat T 4 , T 4 -RIA Henning). The RIA method has also been compared with a CPBA test (Tetralute) for routine application. 1) The results show that CPBA (Tetralute) is superior over the three radioimmuno-assays with regard to intra-assay variance. The T 4 -RIA Abbott has been inferior to the two other RIA under test and to the Tetralute with regard to inter-assay variance. 2) The four test kits show significant differences and considerable deviations from the given nominal values in comparison with the mean values of two control sera. A control for correctness does not seem to be appropriate as it cannot be decided which of the test kits yields the true value of T 4 content. No systematic difference has been observed between RIA and CPBA in the determination of T 4 in control sera. 3) No detectable difference has been found among the RIA-T 4 test kits and comparing them with the CBPA test regarding their diagnostic precision. A good correlation of T 4 values of euthyroid patients comparing the Tetralute and the three radioimmunological test kits. The mean values of euthyroid sera obtained by the three radioimmuno-assays and the Tetralute are not in agreement with each other. (orig.) [de

Plasma levels of gastrointestinal regulatory peptides in patients receiving maintenance hemodialysis

International Nuclear Information System (INIS)

Hegbrant, J.; Thysell, H.; Ekmann, R.

1991-01-01

The fasting plasma levels of nine gastrointestinal regulatory peptides were measured by radioimmunoassay in 13 stable patients with chronic renal failure, receiving hemodialysis treatment regularly and compared with those of ten healthy controls. The plasma concentrations of gastrin-releasing peptide, motilin, neurotensin, pancreatic polypeptide, peptide YY, somatostatin, substance P, and vasoactive intestinal peptide were increased. The plasma level of gastrin was not statistically different from that of the control (p=0.077). It is concluded that patients with chronic renal failure, receiving hemodialysis treatment regularly, have increased concentrations of eight of nine measured gastrointestinal regulatory peptides. The elevated levels of gastrointestinal peptides in patients with chronic renal failure may contribute to uremic gastrointestinal symptoms and dysfunctions. It is necessary to make a renal function evaluation before interpreting measured plasma levels of gastrointestinal regulatory peptides. 62 refs., 2 tabs

A simple method for the determination of the specific activity of 125I-tracer used in radioimmunoassay

International Nuclear Information System (INIS)

Bhupal, V.; Mani, R.S.

1986-01-01

The specific activity of the 125 I-thyroxin used in thyroxin radioimmunoassay (RIA) was determined by a simple method involving combination of RIA and displacement analysis. It was compared with the value obtained by the conventional method based on radioiodination data. It is indicated that even for a non-protein hormone like thyroxin the specific activity of 125 I-thyroxin derived from iodination data is not reliable. The specific activites obtained by displacement analysis were consistent with the experimental findings. (author)

Combination of high pressure liquid chromatography and radioimmunoassay is a powerful tool for the specific and quantitative determination of endorphins and related peptides

NARCIS (Netherlands)

Loeber, J.G.; Verhoef, J.; Burbach, J.P.H.; Witter, A.

1979-01-01

A method for the separation and subsequent quantification of endorphins and related peptides was developed. Separation of the peptides was achieved by high pressure liquid chromatography on a reversed phase column. By virtue of the high resolving capacity of this system peptides differing in only

Improved radioimmunoassay for creatine kinase isoenzymes in plasma

International Nuclear Information System (INIS)

Ritter, C.S.; Mumm, S.R.; Roberts, R.

1981-01-01

We describe convenient and relatively rapid procedures for purifying creatine kinase isoenzymes MM, BB, and MB, and their use in an improved radioimmunoassay for creatine kinase isoenzymes in plasma. The modifications include use of: (a) BB with a specific activity of 400 kU/G, which can be labeled with a specific radioactivity of 20 Ci/g; (b) albumin-free purified MB as inhibitor; (c) antiserum to MB creatine kinase; and (d) a second-antibody technique that necessitates only a 15-min incubation. The radioimmunoassay for MB has a sensitivity of 0.2 μg/L (80 mU/L) and a CV of <5%. Plasma MB average 22 (SD 12) μg/L in 200 normal subjects; 24 (SD 12) μg/L in 200 patients with chest pain without infarction; and 23 (SD 7) μg/L in 43 patients with renal disease, whether measured before or after dialysis. Peak values for plasma MB averaged 191 (SD 86) μg/L in 325 patients with documented myocardial infarction; BB was negligible. Extensive clinical experience indicates the radioimmunoassay to be suitably rapid, highly sensitive, and reliable as a diagnostic assay for MB on plasma

Insulin and C peptide response, and antibody levels in hepatitis C related chronic liver disease

International Nuclear Information System (INIS)

Abbas, Z.; Tariq, N.; Iqbal, M.; Shah, M.A.

2002-01-01

Objective: Patients with cirrhosis due to hepatitis C (HC) have an increased prevalence of diabetes mellitus. The pathogenic mechanism by which HC predisposes to DM is not clear. The objective of this study was to determine the insulin and C-peptide response to 75 gram oral glucose load and measure anti phospholipid antibody levels in patients with chronic liver disease due to HC. Design: a prospective study. Place and duration of study: This study was conducted at the department of medicine, Jinnah postgraduate medical centre over period of three months. Subjects and methods: An analytical case control study was carried out on 37 patients (m-18,f=19); none of these patients had received interferon. They were divided into four groups: (a) HC cirrhosis with DM (n=9 ), (b) HC cirrhosis without DM (n=11), (c) hepatitis B (HB) cirrhosis without DM (n=7), (d) chronic hepatitis C without DM (n=10). Group C and D were taken as controls. Fasting blood samples were taken and repeated after 2 hours of 75 gram oral glucose load (2 h PG). Result: mean ages of group A,B,C and D were (yr +- SD) 51.3 +- 7.6,48.9 +- 2.4, 33.7 +-10.8 and 31.7 +- 8.8 respectively. There was no statistically significant difference in the age, Pugh score and body mass index of HC cirrhotic patients with and without DM. Patients of group A had higher fasting and 2 h PG glucose levels (P=0.003 and 0.000) and higher fasting insulin level (p=0.045). However, increments in insulin and c peptide levels 2 h PG were much less (p=0.048 and 0.003). HB cirrhotics without diabetes (group C behaved just like HC cirrhotic without diabetes (group B). Patients of group D had normal glucose tolerance and insulin and C peptide levels. All four groups had normal anti phospholipid antibody levels. Conclusion: Patients with cirrhosis due to HC nd HB show evidence of glucose intolerance in spite of hyperinsulinaemia probably due to insulin resistance. HC cirrhotics with diabetes have fasting hyperglycemia in spite of

Gonadotropin determination in 24-h-urine by sensitive LH and FSH radioimmunoassays

International Nuclear Information System (INIS)

Raid, A.; Fenske, M.; Koenig, A.

1979-01-01

Urinary lutropin (LH) and follitropin (FSH) were precipitated with acetone and measured by specific radioimmunoassays. Recovery experiments with special regard to urinary pH values were done by adding 125 I-labelled LH and FSH to unprocessed urine. At pH 4.5 68.6% of LH and 66.1% of FSH were recovered. Increasing pH values up to 6.0 resulted in a significant recovery loss of 125 I-LH, but not of 125 I-FSH. Immunoreactive FSH concentrations decreased significantly 6 and 48 hours after starting storage at room temperature. In healthy males and females there were found mean LH and FSH concentrations in 24-h-urine which were similar to those reported by others: LH: males: 22.6 IU; cycling females: 17.8 IU; postmenopausal females: 49.1 IU; FSH: males 6.0 IU; cycling females: 15.0 IU; postmenopausal females: 48.5 IU. Because of their high sensitivity and practicability. These radioimmunoassays could be clinically useful approaches in assessment of pituitary and gonadal disorders in human subjects. (author)

Radioimmunoassays - what is their diagnostic value

International Nuclear Information System (INIS)

Panitz, N.

1983-01-01

A selection is made of hormones and enzymes which are measurable by radioimmunoassay and their organ-specific function is described. Endocrine function tests together with the stimulating or suppressing substances, reaction in the organism and the examined regulation are listed. Non-radioactive immunological determination methods and the use of monoclonal antibodies in vitro and in vivo with ''tumor imaging'' are indicated. (orig.) [de

Evaluation of radioimmunoassay of anti-thyroglobulin antibodies

International Nuclear Information System (INIS)

Lourme, J.; Dessaint, J.P.; Capron, A.

1985-01-01

A statistical analysis is performed on the results of 881 determinations of thyroglobulin antibodies in humans. Antibodies were assayed comparatively by radioimmunoassay using a sandwich method and by tanned red cell haemagglutination. A very good concordance was found between the two techniques, apart from the low titer zone. A significant correlation was observed between on the one side, the radioactivity index of the diluted serum, defined as the increment of radioactivity bound by undiluted patient serum over the positive threshold, divided by this threshold, and, on the other side, the antibody titer, i.e. the reciprocal of the highest serum dilution superior to the positive threshold by radioimmunoassay. The corresponding linear regression allows to define a arbitrary unit system which associates values of the radioactivity index with an average antibody titer [fr

Identification and accurate quantification of structurally related peptide impurities in synthetic human C-peptide by liquid chromatography-high resolution mass spectrometry.

Science.gov (United States)

Li, Ming; Josephs, Ralf D; Daireaux, Adeline; Choteau, Tiphaine; Westwood, Steven; Wielgosz, Robert I; Li, Hongmei

2018-06-04

Peptides are an increasingly important group of biomarkers and pharmaceuticals. The accurate purity characterization of peptide calibrators is critical for the development of reference measurement systems for laboratory medicine and quality control of pharmaceuticals. The peptides used for these purposes are increasingly produced through peptide synthesis. Various approaches (for example mass balance, amino acid analysis, qNMR, and nitrogen determination) can be applied to accurately value assign the purity of peptide calibrators. However, all purity assessment approaches require a correction for structurally related peptide impurities in order to avoid biases. Liquid chromatography coupled to high resolution mass spectrometry (LC-hrMS) has become the key technique for the identification and accurate quantification of structurally related peptide impurities in intact peptide calibrator materials. In this study, LC-hrMS-based methods were developed and validated in-house for the identification and quantification of structurally related peptide impurities in a synthetic human C-peptide (hCP) material, which served as a study material for an international comparison looking at the competencies of laboratories to perform peptide purity mass fraction assignments. More than 65 impurities were identified, confirmed, and accurately quantified by using LC-hrMS. The total mass fraction of all structurally related peptide impurities in the hCP study material was estimated to be 83.3 mg/g with an associated expanded uncertainty of 3.0 mg/g (k = 2). The calibration hierarchy concept used for the quantification of individual impurities is described in detail. Graphical abstract ᅟ.

Radioimmunoassay for detection of IgM domains

Energy Technology Data Exchange (ETDEWEB)

Shimizu, A [Osaka Univ. (Japan); Watanabe, S; Kiyotaki, C; Yamamura, Y

1979-09-01

IgM from two macroglobulinemia patients was digested with trypsin, and Fab monomer, Fab dimer and Fc fragments of the IgM were isolated. Using these fragments as antigens and rabbit antisera prepared against another IgM from a macroglobulinemia patient, a radioimmunoassay system for the C..mu..1, C..mu..2 and Fc..mu.. was established. This system can be used as a tool for immunochemical characterization of IgM present on the surface of lymphoid cells.

Synthesis and screening of peptide libraries with free C-termini.

Science.gov (United States)

Wang, Yen-Chih; Distefano, Mark D

2014-01-01

Peptide libraries are useful tools to investigate the relationship between structure and function of proteins. The creation of peptide libraries with free C-termini presents unique synthetic challenges. In this review, methods for creating peptide libraries using either solid-phase peptide synthesis or phage display are described. Methods for screening such libraries and their application in studying several important biological problems are also reported.

Stereochemical determinants of C-terminal specificity in PDZ peptide-binding domains: a novel contribution of the carboxylate-binding loop.

Science.gov (United States)

Amacher, Jeanine F; Cushing, Patrick R; Bahl, Christopher D; Beck, Tobias; Madden, Dean R

2013-02-15

PDZ (PSD-95/Dlg/ZO-1) binding domains often serve as cellular traffic engineers, controlling the localization and activity of a wide variety of binding partners. As a result, they play important roles in both physiological and pathological processes. However, PDZ binding specificities overlap, allowing multiple PDZ proteins to mediate distinct effects on shared binding partners. For example, several PDZ domains bind the cystic fibrosis (CF) transmembrane conductance regulator (CFTR), an epithelial ion channel mutated in CF. Among these binding partners, the CFTR-associated ligand (CAL) facilitates post-maturational degradation of the channel and is thus a potential therapeutic target. Using iterative optimization, we previously developed a selective CAL inhibitor peptide (iCAL36). Here, we investigate the stereochemical basis of iCAL36 specificity. The crystal structure of iCAL36 in complex with the CAL PDZ domain reveals stereochemical interactions distributed along the peptide-binding cleft, despite the apparent degeneracy of the CAL binding motif. A critical selectivity determinant that distinguishes CAL from other CFTR-binding PDZ domains is the accommodation of an isoleucine residue at the C-terminal position (P(0)), a characteristic shared with the Tax-interacting protein-1. Comparison of the structures of these two PDZ domains in complex with ligands containing P(0) Leu or Ile residues reveals two distinct modes of accommodation for β-branched C-terminal side chains. Access to each mode is controlled by distinct residues in the carboxylate-binding loop. These studies provide new insights into the primary sequence determinants of binding motifs, which in turn control the scope and evolution of PDZ interactomes.

Stability and reproducibility of a single-sample urinary C-peptide/creatinine ratio and its correlation with 24-h urinary C-peptide.

Science.gov (United States)

McDonald, Tim J; Knight, Bridget A; Shields, Beverley M; Bowman, Pamela; Salzmann, Maurice B; Hattersley, Andrew T

2009-11-01

C-peptide measurement in blood or 24-h urine samples provides useful information regarding endogenous insulin secretion, but problems related to the rapid degradation of C-peptide in blood and difficulty of 24-h urine collection have limited widespread routine clinical use of this test. We assessed the feasibility of measuring urinary C-peptide (UCP) with correction for creatinine concentration in single urine samples. We analyzed UCP using a routine electrochemiluminescence immunoassay in samples from 21 healthy volunteers. We investigated the stability of UCP with different preservatives and storage conditions and compared the reproducibility of urinary C-peptide/creatinine ratio (UCPCR) in first- and second-void fasting urines, then assessed correlations with 24-h collections. UCPCR was unchanged at room temperature for 24 h and at 4 degrees C for 72 h even in the absence of preservative. UCPCR collected in boric acid was stable at room temperature for 72 h. UCPCR remained stable after 7 freeze-thaw cycles but decreased with freezer storage time and dropped to 82%-84% of baseline by 90 days at -20 degrees C. Second-void fasting UCPCRs were lower than first-void (median 0.78 vs 1.31, P = 0.0003) and showed less variation (CV 33% vs 52%), as second-void UCPCRs were not influenced by evening food-related insulin secretion. Second-void fasting UCPCR was highly correlated with 24-h UCP (r = 0.8, P = 0.00006). Second-void fasting UCPCR is a reproducible measure that correlates well with 24-h UCP in normal samples. The 3-day stability of UCPCR at room temperature greatly increases its potential clinical utility.

Double antibody solid-phase radioimmunoassay for staphylococcal enterotoxin A

International Nuclear Information System (INIS)

Lindroth, S.; Niskanen, A.

1977-01-01

A double antibody solid-phase (DASP) radioimmunoassay for staphylococcal enterotoxin A is described. In the assay the antigen-antibody complex is precipitated by anti-rabbit serum which is adsorbed onto a solid carrier (cellulose). The method is sensitive to 200 pg of enterotoxin. It was possible to detect a little as 2-5 ng of enterotoxin A/ml food extract from minced meat and sausage. Enterotoxins B and C were not found to inhibit the uptake of labled enterotoxin A at a level which might distort the results of the enterotoxin A assay. The DASP technique is sensitive, rapid, and easy to perform and thus compares favorably with other radioimmunoassays for enterotoxin. (orig.) [de

Association between low C-peptide and fragility fractures in postmenopausal women without diabetes.

Science.gov (United States)

Ferro, Y; Russo, C; Russo, D; Gazzaruso, C; Coppola, A; Gallotti, P; Zambianchi, V; Fodaro, M; Romeo, S; Galliera, E; Marazzi, M G; Romanelli, M M C; Giannini, S; Pujia, A; Montalcini, T

2017-10-01

C-peptide has been shown to exert several, previously unknown, biological effects. A recent cross-sectional study demonstrated an association between low C-peptide serum levels and low lumbar bone density of postmenopausal women not affected by diabetes. To date, very little research attention has been directed toward the association between C-peptide and osteoporotic fractures. To contribute toward filling this gap, we investigated the association between C-peptide and fractures in postmenopausal women. A cohort of 133 non-diabetic postmenopausal women with and without a history of fractures was evaluated in this cross-sectional investigation. Standardized interviews were performed to gather information on the patients' fracture history. All of the participants underwent a bone mineral density assessment by DXA, radiographs, and a serum C-peptide measurement. Thirty-four women presented fractures. Bivariate analysis revealed an inverse correlation between C-peptide and fractures (r = -0.27, p = 0.002). A significant difference in mean C-peptide levels was also found between women with vs. without fractures (p = 0.01, adjusted for age, BMI and glucose). Logistic regression analysis showed that C-peptide levels, femoral and vertebral BMD were all negatively associated with fracture status (B = -1.097, ES = 0.401, p = 0.006, 95% CI 0.15-0.73; B = -15.6, SE = 4.17, p C-peptide levels and a history of fractures in postmenopausal women without diabetes. These results suggest that C-peptidemay exert an effect on bone mineral density. However, further large-scale studies are needed to corroborate this finding and investigate the potential underlying mechanisms involved.

Radioimmunoassay for pantothenic acid in blood and other tissues. [/sup 3/H and /sup 14/C tracer techniques

Energy Technology Data Exchange (ETDEWEB)

Wyse, B.W.; Wittwer, C.; Hansen, R.G.

1979-01-01

We described a radioimmunoassay for pantothenic acid in biological tissues. D-Pantothenic acid was conjugated with bovine serum albumin by use of a bromoacetyl derivative of pantothenic acid, and antibody to this antigen was raised by injecting it into the foot pads of rabbits. For the radioimmunoassay, a 100-fold dilution of the resulting antiserum was incubated with radiolabeled panthothentic acid. The antibodies were precipitated and dissolved, and the radioactivity of the solution was measured in a liquid scintillation counter. Between 5 and 125 ng of pantothenic acid can be detected in 75 ..mu..L of tissue extract. Validation included recovery and precision studies, parallelism with tissue extracts, and competitive binding studies. Results of the radioimmunoassay and those of microbiological assay with use of Lactobacillus plantarum correlated well (r = 0.80).

Determination of antithrombin III by radioimmunoassay and its clinical application

Energy Technology Data Exchange (ETDEWEB)

Chan, V; Chan, T K; Wong, V; Tso, S G; Todd, D [Queen Mary Hospital, Hong Kong

1979-04-01

A radioimmunoassay (RIA) has been developed for the determination of antithrombin III (AT III) in man. The detection limit was 25 ..mu..g/dl. At III-RIA level and biological activity (anti-Xa) was significantly correlated (r = 0.737, P < 0.0001). Plasma levels in 36 healthy males (mean +- SD, 19.9 +- 2.5 mg/dl) and 21 healthy females (19.1 +- 2.4 mg/dl) were similiar. Serial AT III measurements in normal menstruating females showed lower levels during midcycle and higher concentrations during menstruation. In carcinomas, the AT III levels were lower than normal, particularly in hepatocellular carcinoma. In cirrhosis of liver, the levels were markedly decreased and in some patients were below that found in congenital AT III deficiency. Patients with deep vein thrombosis and patients with heart valve replacement had lower levels than normal, while patients with cerebral vascular occlusion had normal levels. The possible use of AT III as a diagnostic tool of post-operative deep vein thrombosis was demonstrated in one patient after hysterectomy. The increased sensitivity, specificity and precision of this type of assay offer distinct advantages over existing methods of AT III estimation.

A radioimmunoassay method for the novel gastrointestinal prokinetic agent, renzapride, in plasma

International Nuclear Information System (INIS)

Al-Azawie, D.M.; Webb, A.J.; Kelly, H.C.; Davies, B.E.

1990-01-01

Renzapride, BRL 24924 {4-amino-5-chloro-2- methoxy-N[4-(1-azabicyclo- [3,3,1] nonyl) benzamide]} is a novel compound that enhances gut motility without causing CNS dopamine block or prolactin release. It is being processed as a potential stimulant of upper gut motility and gastric emptying. Until now the only available method used to determine the concentrations of renzapride during clinical studies was a reversed phase h.p.l.c. assay (Kelly and Davies, 1988). Although the h.p.l.c. assay was used to determine renzapride in urine, the technique lacked the sensitivity required to quantify the low concentrations of the drug in plasma. The authors describe the development of a sensitive, specific, and simple radioimmunoassay method that can be used to determine renzapride concentrations in human plasma following therapeutic doses. (author)

Analysis of changes of serum leptin, C-peptide levels and peripheral fat tissue leptin receptor expression in obesity

International Nuclear Information System (INIS)

Du Tongxin; Sun Junjiang; Wang Shukui; Fu Lei

2002-01-01

Objective: To explore the mechanism of obesity and obesity accompanied type two diabetes mellitus by investigating changes of serum leptin, C-peptide (C-P) levels and leptin receptor expression in peripheral adipose tissues. Methods: Peripheral leptin receptor density was measured via radio-ligand binding method, serum leptin and C - P levels were measured via radioimmunoassay in 91 cases (38 in obesity group, 23 in over weight, and 30 in normal controls). Results: With the increase of body mass index (BMI), the peripheral leptin receptor density of the over weight and obese cases decreased and was mash less than that of normal cases (both p<0.01, respectively). There was no statistical differences for Kd value among the three groups, suggesting no associated change between the binding ability of leptin receptor to its ligand. There was a negative correlation between BMI and leptin receptor density (r = -0.70, p < 0.01). The serum leptin and C-P levels in weight excess and obese subjects with type two DM were both increased, but significantly higher in obese group than those in weight excess group (p < 0.01). The increase of C-P was much marked than that of leptin. Serum C-P level was positively correlated with BMI. Conclusion: Changes of serum leptin, C-P levels and peripheral leptin receptor expression in cases with simple obesity and obesity accompanied with type two DM were related closely with BMI. Type 2 DM in obese subjects was related with leptin resistance and insulin resistance

Prediction of Impending Type 1 Diabetes through Automated Dual-Label Measurement of Proinsulin:C-Peptide Ratio.

Directory of Open Access Journals (Sweden)

Annelien Van Dalem

Full Text Available The hyperglycemic clamp test, the gold standard of beta cell function, predicts impending type 1 diabetes in islet autoantibody-positive individuals, but the latter may benefit from less invasive function tests such as the proinsulin:C-peptide ratio (PI:C. The present study aims to optimize precision of PI:C measurements by automating a dual-label trefoil-type time-resolved fluorescence immunoassay (TT-TRFIA, and to compare its diagnostic performance for predicting type 1 diabetes with that of clamp-derived C-peptide release.Between-day imprecision (n = 20 and split-sample analysis (n = 95 were used to compare TT-TRFIA (AutoDelfia, Perkin-Elmer with separate methods for proinsulin (in-house TRFIA and C-peptide (Elecsys, Roche. High-risk multiple autoantibody-positive first-degree relatives (n = 49; age 5-39 were tested for fasting PI:C, HOMA2-IR and hyperglycemic clamp and followed for 20-57 months (interquartile range.TT-TRFIA values for proinsulin, C-peptide and PI:C correlated significantly (r2 = 0.96-0.99; P<0.001 with results obtained with separate methods. TT-TRFIA achieved better between-day %CV for PI:C at three different levels (4.5-7.1 vs 6.7-9.5 for separate methods. In high-risk relatives fasting PI:C was significantly and inversely correlated (rs = -0.596; P<0.001 with first-phase C-peptide release during clamp (also with second phase release, only available for age 12-39 years; n = 31, but only after normalization for HOMA2-IR. In ROC- and Cox regression analysis, HOMA2-IR-corrected PI:C predicted 2-year progression to diabetes equally well as clamp-derived C-peptide release.The reproducibility of PI:C benefits from the automated simultaneous determination of both hormones. HOMA2-IR-corrected PI:C may serve as a minimally invasive alternative to the more tedious hyperglycemic clamp test.

Radioimmunoassay in the diagnosis of arterial hypertension

Energy Technology Data Exchange (ETDEWEB)

Slavnov, V N; Olejnik, V A; Yakovlev, A A; Yugrinov, O G; Markov, V V [Kievskij Nauchno-Issledovatel' skij Inst. Ehndokrinologii i Obmena Veshchestv (Ukrainian SSR)

1984-11-01

The paper is concerned with the results of a study of the aldosterone concentration and renin activity, the general level of catecholamines and their fractions in the peripheral blood and blood taken at selective venography from the vena cava inferior, renal and adrenal veins of 108 patients with hypertension, aldosteroma and idiopathic hyperaldosteronism, adrenal and extraadrenal pheochromocytoma, renovascular and renoparenchymatous arterial hypertension. The aldosterone concentration and renin activity were determined with radioimmunoassay, and the general content of catecholamines and their fractions with a radioenzymatic method using standard kits. It has been shown that the radioimmunoassay to determine the aldosterone concentration and renin activity makes possible differential diagnosis of hypertension, aldosteroma, idiopathic and secondary hyperaldosteronism. A considerable increase in the blood plasma renin activity on the affected side was revealed in the patients with renovascular hypertension, and in renoparenchymatous hypertension it was equal in both renal veins. The study of the total content of catecholamines and their fractions in the blood from different parts of the venous system can be used for topical diagnosis of adrenal and extraadrenal pheochromocytoma.

Radioimmunoassay in the diagnosis of arterial hypertension

International Nuclear Information System (INIS)

Slavnov, V.N.; Olejnik, V.A.; Yakovlev, A.A.; Yugrinov, O.G.; Markov, V.V.

1984-01-01

The paper is concerned with the results of a study of the aldosterone concentration and renin activity, the general level of catecholamines and their fractions in the peripheral blood and blood taken at selective venography from the vena cava inferior, renal and adrenal veins of 108 patients with hypertension, aldosteroma and idiopathic hyperaldosteronism, adrenal and extraadrenal pheochromocytoma, renovascular and renoparenchymatous arterial hypertension. The aldosterone concentration and renin activity were determined with radioimmunoassay, and the general content of catecholamines and their fractions with a radioenzymatic method using standard kits. It has been shown that the radioimmunoassay to determine the aldosterone concentration and renin activity makes it possible to resort to differential diagnosis of hypertension, aldosteroma, idiopathic and secondary hyperaldosteronism. A considerable increase in the blood plasma renin activity on the affected side was revealed in the patients with renovascular hypertension, and in renoparenchymatous hypertension it was equal in both renal veins. The study of the total content of catecholamines and their fractions in the blood from different parts of the venous system can be used for topical diagnosis of adrenal and extraadrenal pheochromocytoma

Delta antibody radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Kselikova, M; Urbankova, J

1985-11-15

The principle and procedure are described of the radioimmunoassay of delta antibody (delta-Ab) using the ABBOTT ANTI-DELTA kit by Abbott Co. A description is given of the kit, the working procedure and the method of evaluation. The results are reported of the incidence of delta-Ab in sera of patients with viral hepatitis B, in haemophiliacs, carriers of the hepatitis B virus surface antigen (HBsAg) and blood donors. The presence was detected of delta-Ab in one HBsAg carrier. The necessity is emphasized of delta-Ab determinations in the blood of donors in view of the antibody transfer with blood and blood preparations.

Radioimmunoassay of deoxynivalenol in wheat and corn

International Nuclear Information System (INIS)

Xu, Y.C.; Zhang, G.S.; Chu, F.S.

1986-01-01

With the availability of antibody against deoxynivalenol triacetate (DON-triacetate), a radioimmunoassay (RIA) for DON in wheat was developed. DON is extracted from the sample with acetonitrile-water defatted with hexane, and then reacted with acetic anhydride to form DON-triacetate. The reaction mixture is loaded onto a C-18 cartridge to remove excess reagents and impurities. Acetylated DON is eluted from the cartridge with 50% methanol in water, and then analyzed by radioimmunoassay utilizing antiserum against DON-triacetate and tritiated DON-triacetate. Overall recovery for DON added to wheat between 50 and 5000 ppb was 86% with a standard deviation of 7% and coefficient of variation of 8%. The limit of detection for DON was about 20 ppb. Analysis of 12 naturally contaminated wheat, corn, and mixed feed samples for DON revealed that RIA results agreed well with thin layer chromatographic analyses performed by other laboratories

Lipopolysaccharide interactions of C-terminal peptides from human thrombin.

Science.gov (United States)

Singh, Shalini; Kalle, Martina; Papareddy, Praveen; Schmidtchen, Artur; Malmsten, Martin

2013-05-13

Interactions with bacterial lipopolysaccharide (LPS), both in aqueous solution and in lipid membranes, were investigated for a series of amphiphilic peptides derived from the C-terminal region of human thrombin, using ellipsometry, dual polarization interferometry, fluorescence spectroscopy, circular dichroism (CD), dynamic light scattering, and z-potential measurements. The ability of these peptides to block endotoxic effects caused by LPS, monitored through NO production in macrophages, was compared to peptide binding to LPS and its endotoxic component lipid A, and to size, charge, and secondary structure of peptide/LPS complexes. While the antiendotoxic peptide GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE) displayed significant binding to both LPS and lipid A, so did two control peptides with either selected D-amino acid substitutions or with maintained composition but scrambled sequence, both displaying strongly attenuated antiendotoxic effects. Hence, the extent of LPS or lipid A binding is not the sole discriminant for the antiendotoxic effect of these peptides. In contrast, helix formation in peptide/LPS complexes correlates to the antiendotoxic effect of these peptides and is potentially linked to this functionality. Preferential binding to LPS over lipid membrane was furthermore demonstrated for these peptides and preferential binding to the lipid A moiety within LPS inferred.

Diagnostic informative value of gastroduodenal regulatory peptides of the blood serum on an empty stomach and after test breakfasts of various compositions

International Nuclear Information System (INIS)

Ablyazov, A.A.; Korot'ko, G.F.

1992-01-01

Gastrin, secretin and cholecystokinin were determined by a radioimmunoassay in healthy persons (19) and in patients with peptic ulcer (13) on an empty stomach and after test breakfasts with different nutrients. In the healthy persons the blood concentration of regulatory peptides was lower than in the patients. Breakfasts increased the concentrations of gastrin, secretin and cholecystokinin in the patients much more than in the controls. Some differences in changes of the blood concentration of peptides were noted with regard to a type of test breakfast. However differentiated reactions of the endocrine apparatus of the gastroduodenal complex in response to the breakfasts were not a reliable functional and diagnostic criterion

A simplified radioimmunoassay of adenosine-3':5'-monophosphate

International Nuclear Information System (INIS)

Katoh, Yoshiki; Takezawa, Junichi; Suzuki, Morio; Kuninaka, Akira; Yoshino, Hiroshi

1975-01-01

Dextran-coated charcoal was proved to be able to separate free adenosine-3':5'monophosphate (cAMP) from antibody-bound cAMP. Only free cAMO was adsorbed on dextran-coated charcoal within 1 min after contacting the charcoal. In a reaction mixture of cAMP and anti-cAMP-plasma, most of antibody-bound cAMP had not been adsorbed 4 min after contacting. The data obtained were found to be almost the same as the data of another experiment using cellulose ester filter separation technique. Thus, dextran-coated charcoal could be employed to simplify the radioimmunoassay of cAMP. (author)

Radioimmunoassay for tumor antigen of human cervical squamous cell carcinoma

International Nuclear Information System (INIS)

Kato, H.; Torigoe, T.

1977-01-01

A heterologous antiserum for human cervical squamous cell carcinoma was prepared and specificity determined by Ouchterlony immunodiffusion and immunofluorescence studies. With this antiserum, a tumor antigen was purified from human cervical squamous cell carcinoma tissue. The specificities of the antigen and the antiserum were then re-examined by a radioimmunoassay method using 125 I-labeled purified antigen. Although normal cervical tissue extract showed a moderate cross-reactivity in the radioimmunoassay, the circulating antigen activity could not be detected in normal women or in several patients with other carcinomas, whereas 27 of 35 patients with cervical squamous cell carcinoma showed detectable serum antigen activity. All patients with advanced stages of cervical squamous cell carcinoma showed detectable antigen levels. These results indicate that there is a quantitative abnormality, at least, of this tumor antigen in patients with cervical squamous cell carcinoma and that the radioimmunoassay for the antigen is a potentially useful tool in clinical care

Radioimmunoassay of hair for determining opiate-abuse histories

International Nuclear Information System (INIS)

Baumgartner, A.M.; Jones, P.F.; Baumgartner, W.A.; Black, C.T.

1979-01-01

Heroin and morphine metabolites can be detected in hair with the use of commerically available radioimmunoassay reagents and with minor sample preparation. Hair samples obtained from morphine-treated mice and heroin users contained nanogram levels of the drug per milligram of hair (single human hair). The results of the hair analyses for all subjects admitting the use of heroin were positive, whereas the results of only 30% of thin-layer chromatographic urinanalyses of these same subjects were positive. In addition, differences in drug concentration for sections of hair near the scalp and near the distal end correlated with the length of time the drug had been used. These results exemplify the potential advantages of the use of hair analysis over urine and serum analyses in terms of accessibility, sample stability, and long-term retention of information

Bioorthogonal Diversification of Peptides through Selective Ruthenium(II)-Catalyzed C-H Activation.

Science.gov (United States)

Schischko, Alexandra; Ren, Hongjun; Kaplaneris, Nikolaos; Ackermann, Lutz

2017-02-01

Methods for the chemoselective modification of amino acids and peptides are powerful techniques in biomolecular chemistry. Among other applications, they enable the total synthesis of artificial peptides. In recent years, significant momentum has been gained by exploiting palladium-catalyzed cross-coupling for peptide modification. Despite major advances, the prefunctionalization elements on the coupling partners translate into undesired byproduct formation and lengthy synthetic operations. In sharp contrast, we herein illustrate the unprecedented use of versatile ruthenium(II)carboxylate catalysis for the step-economical late-stage diversification of α- and β-amino acids, as well as peptides, through chemo-selective C-H arylation under racemization-free reaction conditions. The ligand-accelerated C-H activation strategy proved water-tolerant and set the stage for direct fluorescence labelling as well as various modes of peptide ligation with excellent levels of positional selectivity in a bioorthogonal fashion. The synthetic utility of our approach is further demonstrated by twofold C-H arylations for the complexity-increasing assembly of artificial peptides within a multicatalytic C-H activation manifold. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Programs for radioimmunoassays and radioreceptorassays using SPSS-X.

Science.gov (United States)

Amador, A G; Hodges, S L

1989-01-01

Two sets of programs written using SPSS-X, and designed for the analysis of data obtained by radioimmunoassay or radioreceptorassay are presented. The main advantages of the programs are that they are easily edited, their commands are simple and logical, and they can be used for any type of radioimmunoassay or radioreceptorassay, respectively. The programs for radioimmunoassay can also be used for fluorescenceimmunoassay and luminescenceimmunoassay.

The non-peptidic part determines the internalization mechanism and intracellular trafficking of peptide amphiphiles.

Directory of Open Access Journals (Sweden)

Dimitris Missirlis

Full Text Available BACKGROUND: Peptide amphiphiles (PAs are a class of amphiphilic molecules able to self-assemble into nanomaterials that have shown efficient in vivo targeted delivery. Understanding the interactions of PAs with cells and the mechanisms of their internalization and intracellular trafficking is critical in their further development for therapeutic delivery applications. METHODOLOGY/PRINCIPAL FINDINGS: PAs of a novel, cell- and tissue-penetrating peptide were synthesized possessing two different lipophilic tail architectures and their interactions with prostate cancer cells were studied in vitro. Cell uptake of peptides was greatly enhanced post-modification. Internalization occurred via lipid-raft mediated endocytosis and was common for the two analogs studied. On the contrary, we identified the non-peptidic part as the determining factor of differences between intracellular trafficking and retention of PAs. PAs composed of di-stearyl lipid tails linked through poly(ethylene glycol to the peptide exhibited higher exocytosis rates and employed different recycling pathways compared to ones consisting of di-palmitic-coupled peptides. As a result, cell association of the former PAs decreased with time. CONCLUSIONS/SIGNIFICANCE: Control over peptide intracellular localization and retention is possible by appropriate modification with synthetic hydrophobic tails. We propose this as a strategy to design improved peptide-based delivery systems.

A new procedure for coupling antibody to paper discs for radioimmunoassay: application to the determination of alpha-fetoprotein

International Nuclear Information System (INIS)

Sasaki, T.; Tsukada, Y.; Hirai, H.

1983-01-01

Horse anti-alpha-fetoprotein was coupled to CM-cellulose discs by a modified carbodiimide reaction. The resulting coupled CM-discs were used in solid-phase radioimmunoassay of human alpha-fetoprotein. The sensitivity of these discs and conventional BrCN activated filter paper discs coupled anti-alpha-fetoprotein was approximately the same. A fair correlation between the alpha-fetoprotein levels determined by both methods was observed. The coupling procedure with carbodiimide is simple and the use of hazardous BrCN is eliminated. (Auth.)

Radioimmunoassay for Lys8, Asn9, neurotensin 8-13: tissue and subcellular distribution of immunoreactivity in chickens

International Nuclear Information System (INIS)

Carraway, R.E.; Ruane, S.E.; Ritsema, R.S.

1983-01-01

A sensitive and specific radioimmunoassay (RIA) for Lys8, Asn9, neurotensin 8-13 (LANT-6) has been developed which utilizes 125I-labeled LANT-6 and rabbit antisera raised towards conjugates of synthetic LANT-6 and bovine thyroglobulin. The antiserum described (TG-22) allows the detection of ca 100 fmol of LANT-6 and crossreacts less than 0.01% with chicken or bovine NT. Dose-response relationships for the native (chicken) and synthetic peptides were indistinguishable. Using this assay the distribution of immunoreactive LANT-6 (iLANT-6) through various tissues of the chicken was studied and compared with that of chicken NT (iNT) determined by RIA. Both iNT and ILANT-6 were found primarily in the brain and gastrointestinal tract, however, their regional distributions were found to differ. Subcellular distribution studies in homogenates of chicken brain indicated that both iNT and iLANT-6 were associated with synaptosome-like and vesicle-like particles. In homogenates of small intestine, pancreas and colon iNT and iLANT-6 appeared to be within osmotically sensitive, sedimentable particles. Analyses using high pressure liquid chromatography established that chicken iLANT-6 co-eluted with the synthetic peptide and that similar substances were present in extracts of rat brain and intestine. These results are consistent with ''messenger' roles for these peptides

Development of a radioimmunoassay for the determination of buprenorphine in biological samples

International Nuclear Information System (INIS)

Debrabandere, L.; Boven, M. Van; Daenens, P.

1993-01-01

The development of a specific and sensitive radioimmunoassay for the detection of buprenorphine in urine samples is described. With minor adjustments, the assay was also applied to the analysis for buprenorphine in plasma samples. The 2-diazobenzoic acid derivative of buprenorphine has been prepared as a hapten. The immunization of rabbits with the hapten-bovine serum albumin conjugate resulted in the production of antibodies, which cross-reacted with N-dealkylbuprenophine up to about the 90% level. The antibodies showed very low cross-reactivities with the 3-O-glucuronides and with the structural analogue etorphine. The assay was mainly used to prescreen for buprenorphine in urine samples of persons suspected of Temgesic misuse and to determine buprenorphine in plasma samples. A linear calibration graph for buprenorphine was obtained after logit-log regression. The spiking recovery study showed a linear regression. Intra-and inter-assay relative standard deviations were -1 (Student's t-distribution, p 0.01, degrees of freedom = 8). (Author)

Radioimmunoassay determination of the effect on animal reproduction of alternative of feeding suplementation in dairy cows

International Nuclear Information System (INIS)

Villalba, Patricio; Ambuludi, Eduardo

1993-01-01

The principal object of this trial was to evaluate the influence of three alternatives of feeding suplementation in dairy cows in the post-partum period in ecuadorian highlands. Thirty sic animals in fist lactation were used in this experiment and were divided in three groups according to the feed intake: Group A diet was 5 Kg. of a commercial concentrate mixture with 12 per cent of crude protein plus pasture ad libitum; Group B diet was green banans (Musa paradisiaca) and pasture and Group C diet was the control only pasture. Using Radioimmunoassay technique (RIA), progesterone values were determinated in milk from each cow. the sampling was sequential, two samples a week, starting 6 days after parturition, until the animal was pregnant or until the study was finished, 150 days after post-partum for each cow. This research allowed us to evaluate the ovaric post-partum activity of each group: Frequency and length of the oestrus cycles; efficiency of oestrus detection, calving-first, oestrus period, calving-conception length, conception rate, and services per conception. Additional datas were used in this study such as: milk production, palpations and treatments

Radioimmunoassay of cholylglycine in serum

International Nuclear Information System (INIS)

Wakushima, Tadashi; Yamanishi, Yasuhito; Hirayama, Chisato

1979-01-01

Serum levels of cholylglycines (CG) were determined by radioimmunoassay and that of total bile acids (TBA) by enzymatic method. In normal subjects, serum levels of CG, TBA and CG/TBA ratio were 0.6 +- 0.4 μM, 7 +- 2 μM, and 0.08 +- 0.06, respectively. They were increased markedly in acute hepatitis and moderately in chronic hepatitis and cirrhosis. Thus, measurement of serum CG as compared with serum TBA appears to be a sensitive liver test. (author)

Simultaneous radioimmunoassay for luteinizing hormone and prolactin

International Nuclear Information System (INIS)

Steele, M.K.; Deschepper, C.F.

1985-01-01

A combined radioimmunoassay (RIA) for the measurement of the anterior pituitary proteins luteinizing hormone (LH) and prolactin (PRL) is described and compared with individual RIAs for these hormones. The standard curves and the sample values for LH and PRL were identical when determined in a combined or in an individual RIA. This technique may prove useful to a number of laboratories where it is desirable to determine levels of more than one hormone in limited sample volumes

Development of a radioimmunoassay of tetracycline and its derivatives

International Nuclear Information System (INIS)

Zitzewitz, A. von.

1981-01-01

A radioimmunoassay for tetracycline was developed in the context of the present work. The determination of tetracycline content in biological samples is to be made valid using tetracycline RIA. As well as the carbodiimide method, a by radioimmunologists extremely seldomly used way involving a condensation reaction between protein and haptene via the Mannich reaction was successfully applied. Antibodies were produced using a conventional immunisation method after Abraham, the other applied alternative method after Vaitukaitis et al. The general working methods had to be adapted to the tetracycline RIA. All variable parameters of the antigen-antibody bond were tested to optimize the incubation conditions of the system as well as to control the tracer for a degradation. The detection limit of RIA is 10 - 12 , the measuring range from 10 - 12 to 10 - 10 mol for tetracycline hydrochloride and rolitetracycline respectively and up to 10 - 9 mol for its derivates. The investigations for cross reactions showed a high specificity for tetracycline (100%) and its intravenously appliable pyrrolidino-methyl derivative rolitetracycline (88%). Standard curves could be drawn up using either of the two compounds tetracycline and rolitetracycline as standard. The pharmaco-kinetic behaviour of the parenteral administrable tetracycline was analyzed as example for the possible applications of the tetracycline radioimmunoassay. Parallel animal tests administring 3 H tetracycline hydrochloride were performed for radioimmunoassay reference. The possible application of tetracycline radioimmunoassay in food analysis is discussed. (orig./MG) [de

Circulating osteocrin stimulates bone growth by limiting C-type natriuretic peptide clearance.

Science.gov (United States)

Kanai, Yugo; Yasoda, Akihiro; Mori, Keita P; Watanabe-Takano, Haruko; Nagai-Okatani, Chiaki; Yamashita, Yui; Hirota, Keisho; Ueda, Yohei; Yamauchi, Ichiro; Kondo, Eri; Yamanaka, Shigeki; Sakane, Yoriko; Nakao, Kazumasa; Fujii, Toshihito; Yokoi, Hideki; Minamino, Naoto; Mukoyama, Masashi; Mochizuki, Naoki; Inagaki, Nobuya

2017-11-01

Although peptides are safe and useful as therapeutics, they are often easily degraded or metabolized. Dampening the clearance system for peptide ligands is a promising strategy for increasing the efficacy of peptide therapies. Natriuretic peptide receptor B (NPR-B) and its naturally occurring ligand, C-type natriuretic peptide (CNP), are potent stimulators of endochondral bone growth, and activating the CNP/NPR-B system is expected to be a powerful strategy for treating impaired skeletal growth. CNP is cleared by natriuretic peptide clearance receptor (NPR-C); therefore, we investigated the effect of reducing the rate of CNP clearance on skeletal growth by limiting the interaction between CNP and NPR-C. Specifically, we generated transgenic mice with increased circulating levels of osteocrin (OSTN) protein, a natural NPR-C ligand without natriuretic activity, and observed a dose-dependent skeletal overgrowth phenotype in these animals. Skeletal overgrowth in OSTN-transgenic mice was diminished in either CNP- or NPR-C-depleted backgrounds, confirming that CNP and NPR-C are indispensable for the bone growth-stimulating effect of OSTN. Interestingly, double-transgenic mice of CNP and OSTN had even higher levels of circulating CNP and additional increases in bone length, as compared with mice with elevated CNP alone. Together, these results support OSTN administration as an adjuvant agent for CNP therapy and provide a potential therapeutic approach for diseases with impaired skeletal growth.

Radioimmunoassay of bleomycin in plasma and urine

International Nuclear Information System (INIS)

Teale, J.D.; Clough, J.M.; Marks, V.

1977-01-01

Antibodies to bleomycin were raised by immunization of sheep and rabbits with bleomycin-albumin conjugates. The combination of a high-titre, high-avidity sheep antiserum and iodinated bleomycin produced a radioimmunoassay sensitive to 8 ng of bleomycin per ml of plasma or urine. Untreated specimens (100 μl) of plasma or urine could be added directly to the assay tubes. The anti-serum was specific for bleomycin and showed no cross-reaction with other anti-cancer agents used in combination chemotherapy. Over a concentration range of 20 to 100 ng/ml. recovery of bleomycin from plasma was 110% and from urine, 93%. Repeated assay of plasma samples showed a decrease in bleomycin levels unless the samples were kept at 4 0 C or below. Assay of bleomycin levels in plasma and urine from patients under treatment with bleomycin showed similarities with results reported using a microbiological assay. The radioimmunoassay offers a more reliable, rapid and sensitive method for the measurement of bleomycin. (author)

A radioimmunoassay for neurotensin in human plasma

International Nuclear Information System (INIS)

Blackburn, A.M.; Bloom, S.R.

1979-01-01

A radioimmunoassay was developed for detecting the neurotensin peptide in human plasma. The plasma was specific for neurotensin as no cross-reaction was found with any of the other gut hormones tested. Changes of 5 pmol/l could be detected with 95% confidence. Neurotensin was unstable in both blood and plasma but considerable protection was afforded by addition of aprotinin, rapid separation of plasma and immediate deep freezing. Neurotensin-like immunoreactivity was detected in human plasma in both a small and large molecular form. The mean fasting level of plasma neurotensin-like immunoreactivity in 36 healthy volunteers was 29 +- 3 pmol/l. A significant increment of 27 +- 8 pmol/l plasma neurotensin immunoreactivity was detected after a large meal in nine healthy men. In view of the present results in man and also of neurotensin's potent pharmacological actions in experimental animals, neurotensin appears to fulfil some of the criteria needed for a hormone. (UK)

Stereospecific effects of morphine on plasma opioid peptide levels and nociception in dogs

Energy Technology Data Exchange (ETDEWEB)

Adams, M.L.; Morris, D.L.; Dewey, W.L.

1986-03-05

..beta..-endorphin, (met)enkephalin, and (leu)enkephalin were quantitated in canine plasma by radioimmunoassay (RIA) after extraction of the peptides on Sep Pak C18 cartridges. Plasma samples were taken one hour after a 10 mg/kg s.c. injection of (-)-morphine SO/sub 4/ or (+)-morphine HBr. Antinociception, measured by a dog tail-flick test, and morphine-induced emesis, salivation, diarrhea, and ataxia were quantitated before sampling. Control levels for each dog were taken one week earlier at the same time of day after saline injections. Antinociception, morphine signs, and opioid peptide levels in plasma were significantly increased by (-)-morphine. Antinociception increased from zero to 83.54 +/- 11.0%. The number of morphine signs increased from zero to 2.9 +/- 0.28 per dog. ..beta..-endorphin levels increased from 44.52 +/- 4.25 to 90.6 +/- 7.38 pg/ml; (met)enkephalin levels increased from 253.56 +/- 22.04 to 497.1 +/- 58.12 pg/ml; (leu)-enkephalin increased from 141.65 +/- 12.9 to 313.24 +/- 35.95 pg/ml. None of these effects were observed in the dogs that received (+)-morphine. The conclude that morphine stereospecifically inhibits nociception, induces observable signs, and increases plasma opioid peptide levels in dogs.

Stereospecific effects of morphine on plasma opioid peptide levels and nociception in dogs

International Nuclear Information System (INIS)

Adams, M.L.; Morris, D.L.; Dewey, W.L.

1986-01-01

β-endorphin, [met]enkephalin, and [leu]enkephalin were quantitated in canine plasma by radioimmunoassay (RIA) after extraction of the peptides on Sep Pak C18 cartridges. Plasma samples were taken one hour after a 10 mg/kg s.c. injection of (-)-morphine SO 4 or (+)-morphine HBr. Antinociception, measured by a dog tail-flick test, and morphine-induced emesis, salivation, diarrhea, and ataxia were quantitated before sampling. Control levels for each dog were taken one week earlier at the same time of day after saline injections. Antinociception, morphine signs, and opioid peptide levels in plasma were significantly increased by (-)-morphine. Antinociception increased from zero to 83.54 +/- 11.0%. The number of morphine signs increased from zero to 2.9 +/- 0.28 per dog. β-endorphin levels increased from 44.52 +/- 4.25 to 90.6 +/- 7.38 pg/ml; [met]enkephalin levels increased from 253.56 +/- 22.04 to 497.1 +/- 58.12 pg/ml; [leu]-enkephalin increased from 141.65 +/- 12.9 to 313.24 +/- 35.95 pg/ml. None of these effects were observed in the dogs that received (+)-morphine. The conclude that morphine stereospecifically inhibits nociception, induces observable signs, and increases plasma opioid peptide levels in dogs

Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro*

Science.gov (United States)

Swedberg, Joakim E.; Schroeder, Christina I.; Mitchell, Justin M.; Fairlie, David P.; Edmonds, David J.; Griffith, David A.; Ruggeri, Roger B.; Derksen, David R.; Loria, Paula M.; Price, David A.; Liras, Spiros; Craik, David J.

2016-01-01

Glucagon-like peptide-1 (GLP-1) signaling through the glucagon-like peptide 1 receptor (GLP-1R) is a key regulator of normal glucose metabolism, and exogenous GLP-1R agonist therapy is a promising avenue for the treatment of type 2 diabetes mellitus. To date, the development of therapeutic GLP-1R agonists has focused on producing drugs with an extended serum half-life. This has been achieved by engineering synthetic analogs of GLP-1 or the more stable exogenous GLP-1R agonist exendin-4 (Ex-4). These synthetic peptide hormones share the overall structure of GLP-1 and Ex-4, with a C-terminal helical segment and a flexible N-terminal tail. Although numerous studies have investigated the molecular determinants underpinning GLP-1 and Ex-4 binding and signaling through the GLP-1R, these have primarily focused on the length and composition of the N-terminal tail or on how to modulate the helicity of the full-length peptides. Here, we investigate the effect of C-terminal truncation in GLP-1 and Ex-4 on the cAMP pathway. To ensure helical C-terminal regions in the truncated peptides, we produced a series of chimeric peptides combining the N-terminal portion of GLP-1 or Ex-4 and the C-terminal segment of the helix-promoting peptide α-conotoxin pl14a. The helicity and structures of the chimeric peptides were confirmed using circular dichroism and NMR, respectively. We found no direct correlation between the fractional helicity and potency in signaling via the cAMP pathway. Rather, the most important feature for efficient receptor binding and signaling was the C-terminal helical segment (residues 22–27) directing the binding of Phe22 into a hydrophobic pocket on the GLP-1R. PMID:27226591

Convenient radioimmunoassay for urinary human choriogonadotropin without interference by urinary human lutropin

International Nuclear Information System (INIS)

Wehmann, R.E.; Harman, S.M.; Birken, S.; Canfield, R.E.; Nisula, B.C.

1981-01-01

We have devised a radioimmunoassay (RIA) for human choriogonadotropin (hCG) in first morning-voided urine specimens. Concanavalin A, a lectin, is used to extract and concentrate the hCG from urine. A high-affinity antiserum is used, directed to the hCGβ carboxy-terminal peptide, a unique immunological determinant not shared by the beta subunit of human lutropin. This ensures that urinary human lutropin-related molecules, which interfere with RIAs involving antisera to the intact hCGβ subunit, will not cross react in this assay. A concentration of hCG as low as 0.4 μg/L can be detected in the first morning-voided urine. The effective sensitivity of this assay for the unequivocal detection of hCG production is somewhat better than that achieved with the serum hCG RIA involving antisera to the hCGβ subunit. The improved specificity and sensitivity of this assay, and the greater convenience of collecting samples of urine rather than blood, are clinically useful advantages of this approach to assessing hCG production in humans

Radioiodinated derivatives for steroid radioimmunoassay. Application to the radioimmunoassay of cortisol

International Nuclear Information System (INIS)

Gomez-Sanchez, C.; Milewich, L.; Holland, O.B.

1977-01-01

Gamma-emitting steroid tracers for use in the radioimmunoassay of steroids have a number of advantages over the more common tritiated tracers. The steroid derivatives aldosterone-3-(p-hydroxybenzoyl) hydrazone, aldosterone-3-(p-hydroxyphenylpropionyl)hydrazone, deoxycorticosterone-3-(p-hydroxyphenylpropionyl)hydrazone, and cortisol-3-(p-hydroxyphenylpropionyl)hydrazone were synthesized by a one-step procedure and iodinated ([ 125 I]). To illustrate the usefulness of these derivatives, we describe the details of a cortisol radioimmunoassay. The use of the radioiodinated tracer appeared to increase the specificity of the antigen-antibody reaction when compared with [ 3 H]cortisol. The methodology involved in the preparation of the steroid derivatives described above can be extended to other 3-oxo-4-ene-containing steroids, with the advantages of economy, simplicity, and versatility

Therapeutic drug monitoring by radioimmunoassay: Determination of aminoglycoside antibiotics and vancomycin in plasma

International Nuclear Information System (INIS)

Glaubitt, D.; Drechsler, H.J.; Knoch, K.; Siafarikas, K.

1984-01-01

Radioimmunoassay of aminoglycoside antibiotics (gentamicin, tobramycin, netilmicin) or vancomycin in plasma may considerably aid to assess their appropriate dosage and, if necessary, to rapidly adjust it to the assumed requirement. Thus the dosage of the antibiotic is kept large enough as to lead to the desired therapeutic result but not as high as to cause side effects. (orig.)

Determination of total bile acids in serum. A comparison of a radioimmunoassay with an enzymatic-fluorimetric method

International Nuclear Information System (INIS)

Starkey, B.J.; Marks, V.

1982-01-01

A solid phase radioimmunoassay kit method for total conjugated bile acids has been compared to an enzymatic fluorimetric method for total serum bile acids. The methods were compared with respect to: precision, cross-reactivity (molar equivalence) of different bile salts, recovery of different bile salts from serum, the reference range for a healthy population, linearity, coefficient of correlation, diagnostic effectiveness, cost and ease of assay. Both assays seemed equally capable of predicting the presence or absence of liver disease. Radioimmunoassay had little advantage over the enzymatic-fluorimetric method. Its relative ease was far outweighed by its greater cost and poorer analytical performance. (Auth.)

Effect of Synthetic Truncated Apolipoprotein C-I Peptide on Plasma Lipoprotein Cholesterol in Nonhuman Primates

Directory of Open Access Journals (Sweden)

Rampratap S. Kushwaha

2004-01-01

Full Text Available The present studies were conducted to determine whether a synthetic truncated apoC-I peptide that inhibits CETP activity in baboons would raise plasma HDL cholesterol levels in nonhuman primates with low HDL levels. We used 2 cynomolgus monkeys and 3 baboons fed a cholesterol- and fat-enriched diet. In cynomolgus monkeys, we injected synthetic truncated apoC-I inhibitor peptide at a dose of 20 mg/kg and, in baboons, at doses of 10, 15, and 20 mg/kg at weekly intervals. Blood samples were collected 3 times a week and VLDL + LDL and HDL cholesterol concentrations were measured. In cynomolgus monkeys, administration of the inhibitor peptide caused a rapid decrease in VLDL + LDL cholesterol concentrations (30%–60% and an increase in HDL cholesterol concentrations (10%–20%. VLDL + LDL cholesterol concentrations returned to baseline levels in approximately 15 days. In baboons, administration of the synthetic inhibitor peptide caused a decrease in VLDL + LDL cholesterol (20%–60% and an increase in HDL cholesterol (10%–20%. VLDL + LDL cholesterol returned to baseline levels by day 21, whereas HDL cholesterol concentrations remained elevated for up to 26 days. ApoA-I concentrations increased, whereas apoE and triglyceride concentrations decreased. Subcutaneous and intravenous administrations of the inhibitor peptide had similar effects on LDL and HDL cholesterol concentrations. There was no change in body weight, food consumption, or plasma IgG levels of any baboon during the study. These studies suggest that the truncated apoC-I peptide can be used to raise HDL in humans.

A Convenient Approach to Synthesizing Peptide C-Terminal N-Alkyl Amides

Science.gov (United States)

Fang, Wei-Jie; Yakovleva, Tatyana; Aldrich, Jane V.

2014-01-01

Peptide C-terminal N-alkyl amides have gained more attention over the past decade due to their biological properties, including improved pharmacokinetic and pharmacodynamic profiles. However, the synthesis of this type of peptide on solid phase by current available methods can be challenging. Here we report a convenient method to synthesize peptide C-terminal N-alkyl amides using the well-known Fukuyama N-alkylation reaction on a standard resin commonly used for the synthesis of peptide C-terminal primary amides, the PAL-PEG-PS (Peptide Amide Linker-polyethylene glycol-polystyrene) resin. The alkylation and oNBS deprotection were conducted under basic conditions and were therefore compatible with this acid labile resin. The alkylation reaction was very efficient on this resin with a number of different alkyl iodides or bromides, and the synthesis of model enkephalin N-alkyl amide analogs using this method gave consistently high yields and purities, demonstrating the applicability of this methodology. The synthesis of N-alkyl amides was more difficult on a Rink amide resin, especially the coupling of the first amino acid to the N-alkyl amine, resulting in lower yields for loading the first amino acid onto the resin. This method can be widely applied in the synthesis of peptide N-alkyl amides. PMID:22252422

Structural and pharmacological characteristics of chimeric peptides derived from peptide E and beta-endorphin reveal the crucial role of the C-terminal YGGFL and YKKGE motifs in their analgesic properties.

Science.gov (United States)

Condamine, Eric; Courchay, Karine; Rego, Jean-Claude Do; Leprince, Jérôme; Mayer, Catherine; Davoust, Daniel; Costentin, Jean; Vaudry, Hubert

2010-05-01

Peptide E (a 25-amino acid peptide derived from proenkephalin A) and beta-endorphin (a 31-amino acid peptide derived from proopiomelanocortin) bind with high affinity to opioid receptors and share structural similarities but induce analgesic effects of very different intensity. Indeed, whereas they possess the same N-terminus Met-enkephalin message sequence linked to a helix by a flexible spacer and a C-terminal part in random coil conformation, in contrast with peptide E, beta-endorphin produces a profound analgesia. To determine the key structural elements explaining this very divergent opioid activity, we have compared the structural and pharmacological characteristics of several chimeric peptides derived from peptide E and beta-endorphin. Structures were obtained under the same experimental conditions using circular dichroism, computational estimation of helical content and/or nuclear magnetic resonance spectroscopy (NMR) and NMR-restrained molecular modeling. The hot-plate and writhing tests were used in mice to evaluate the antinociceptive effects of the peptides. Our results indicate that neither the length nor the physicochemical profile of the spacer plays a fundamental role in analgesia. On the other hand, while the functional importance of the helix cannot be excluded, the last 5 residues in the C-terminal part seem to be crucial for the expression or absence of the analgesic activity of these peptides. These data raise the question of the true function of peptides E in opioidergic systems. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Pregnancy-induced rise in serum C-peptide concentrations in women with type 1 diabetes

DEFF Research Database (Denmark)

Nielsen, Lene Ringholm; Rehfeld, Jens F; Pedersen-Bjergaard, Ulrik

2009-01-01

OBJECTIVE: The purpose of this study was to investigate whether pregnancy induces increased insulin production as a marker of improved beta-cell function in women with long-term type 1 diabetes. RESEARCH DESIGN AND METHODS: This was a prospective study of 90 consecutive pregnant women with type 1.......85). Multivariate regression analysis revealed a positive association between the absolute increase in C-peptide concentrations during pregnancy and decreased A1C from 8 to 33 weeks (P = 0.003). CONCLUSIONS: A pregnancy-induced increase in C-peptide concentrations in women with long-term type 1 diabetes...... in 35 women. RESULTS: C-peptide concentrations gradually increased throughout pregnancy regardless of serum glucose concentrations in the 90 women with a median duration of diabetes of 17 years (range 1-36 years). Among 35 women with paired recordings of stimulated C-peptide, C-peptide production...

A solid phase radioimmunoassay for free triiodothyronine in serum: assay development and validation

International Nuclear Information System (INIS)

Liu Fangyan; Zhou Meiying; Yin Linxiang; Yang Jianzhong; Hua Chenglin

1999-01-01

A solid phase radioimmunoassay for free triiodothyronine in serum was developed based on double-antibody coated tubes. The method was turned out to be reliable with good reproducibility, higher sensitivity and easy performance. The measurable range of FT 3 in serum was 1.2 to 38 pmol/L. The mean coefficients of variation within and between assays were 1.79%∼3.18% and 4.72%∼9.31%, respectively. The FT 3 concentrations in euthyroid serum as determined by this method were 2.8 to 7.8 pmol/L. The FT 3 values determined by this new method correlated well with those measured by a commercial radioimmunoassay (r = 0.853)

Isolation and purification of G immunoglobulin from guinea-pig for the production of a second antibody for radioimmunoassay

International Nuclear Information System (INIS)

Silva, S.R.; Borghi, V.C.; Bellini, M.H.; Wajchenberg, W.A.J.

1992-01-01

The IgG of guinea-pig was isolated and purified by precipitation with caprylic acid and the batch absorption with DEAE-cellulose. The efficiency of the operating was verified by the determination of total proteins, during the purification stages. The purity of the end product was proved by immuno electrophoresis face to rabbit serum total antiserum of guinea-pig. it was obtained 240 mg of purity IgG to be used in the production of second specific antibody for radioimmunoassay. (C.G.C.)

Radioimmunoassay analysis of baculovirus granulins and polyhedrins

International Nuclear Information System (INIS)

Summers, M.D.; Hoops, P.

1980-01-01

Granulin and polyhedrin proteins were purified by preparative sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis from the baculoviruses Autographa californica, Rachiplusia ou, Heliothis zea, Heliothis armigera. Trichoplusia ni, and Spodoptera frugiperda. Antisera were raised against Autographa californica (Ac) polyhedrin and Trichoplusia ni (Tn) granulin and analyzed for homologous and heterologous immunoreactivity by immunodiffusion and radioimmunoassay (RIA). Ac polyhedrin and Tn granulin antisera recognized antigenic determinants on several baculovirus polyhedrin and granulin proteins even though the heterologous proteins had different immunoreactivities when compared by competition radioimmunoassay. Antigenic differences among granulin and polyhedrin proteins were also detected by altered slopes of the competition reaction curves. Antiserum raised against Ac polyhedrin which was purified in the presence of SDS was tested by competition RIA for its ability to detect and react with native polyhedrin produced in the infected TN-368 cells. Ac polyhedrin antiserum had similar if not identical ability to bind to native polyhedrin and to polyhedrin purified in the presence of SDS

A radioimmunoassay of gastric inhibitory polypeptide in human plasma

International Nuclear Information System (INIS)

Sarson, D.L.; Bryant, M.G.; Bloom, S.R.

1980-01-01

A sensitive radioimmunoassay for the measurement of human gastric inhibitory polypeptide (GIP), using pure porcine GIP, has been developed. Cross-reactivity of the antiserum with all available mammalian gut peptide preparations was negligible with the exception of glucagon when it was approximately 1%. Two major molecular forms of GIP were detectable in plasma and tissue extracts, one of large molecular size and the other corresponding to the elution coefficient of pure porcine standard. Concentrations of GIP in plasma from 50 normal subjects after overnight fasting were 9+-1.0(S.E.M.) pmol/1 rising to a peak of 34+-2.8 pmol/1 following the ingestion of a small mixed test meal. Ingestion of glucose or fat resulted in a similar rise of plasma GIP, whereas no change was observed after the ingestion of protein. (author)

Antibodies to cytoskeletal proteins as evidenced by immunofluorescence microscopy and radioimmunoassay

International Nuclear Information System (INIS)

Zugehoer, M.; Struy, H.; Morenz, J.

1987-01-01

In patients suffering from chronic hepatitis, collagenosis and infectious mononucleosis, resp., as well as in blood donors antibodies against cytoskeletal antigens such as actin, myosin, actinin, desmin, keratin, and tubulin were determined by radioimmunoassay

Antibodies to cytoskeletal proteins as evidenced by immunofluorescence microscopy and radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Zugehoer, M; Struy, H; Morenz, J

1987-01-01

In patients suffering from chronic hepatitis, collagenosis and infectious mononucleosis, resp., as well as in blood donors antibodies against cytoskeletal antigens such as actin, myosin, actinin, desmin, keratin, and tubulin were determined by radioimmunoassay.

Determination by radioimmunoassay of the sum of oxidized and reduced forms of NAD and NADP in picomole quantities from the same acid extract

International Nuclear Information System (INIS)

Bredehorst, R.; Lengyel, H.; Hilz, H.

1979-01-01

The sum of the amounts of NAD + NADH was determined from the same acid tissue extract with the aid of a highly specific radioimmunoassay for 5'-AMP. NAD was converted to 5'-AMP via ADP-ribose by alkaline treatment while NADH was converted first to ADP-ribose by incubation of the acid extract at 25 0 C followed by alkaline conversion to 5'-AMP. Removal of phosphate groups in NADP and NADPH by treatment of the extracts with alkaline phosphates extended the procedure to the quantification of NADP(H). When combined with enzymic analyses of the oxidized coenzyme forms, NAD/NADH and NADP/NADPH ratios could also be obtained from the same extracts. The sensitivity of the test allows quantification of pyridine nucleotides in the range of 0.1-10 pmol. (orig.)

Importance of radioimmunoassay for the determination of tumor markers in the diagnosis of malignant lymphomas

International Nuclear Information System (INIS)

Purizhanskij, I.I.; Pavlichuk, S.N.; Toritsina, L.K.

1989-01-01

The investigation was conducted to study the role of the determination of tumor markers (CEA, β 2 -microglobulin, IgE and ferritin) in patients with malignant lymphomas. Altogether 66 patients with Hodgkin's disease, 60 with non-Hodgkin's lymphomas and 15 with clinocohematological remission over one year were investigated, using radioimmunoassay with commercial kits of reagents. An increase in the level of β 2 -MG was shown to depend on the spreading of a lymphoproliferative process. An elevated level of IgE was noted in Hodgkin's disease whereas a significant rise was unnoticed in non-Hodgkin's lymphomas. An increase in the level of serum ferritin was noted in an advanced and aggressive lymphoproliferative process. The CEA test in malignant lymphomas is not informative

The determination of antithrombin III by radioimmunoassay and its clinical application

International Nuclear Information System (INIS)

Chan, V.; Chan, T.K.; Wong, V.; Tso, S.G.; Todd, D.

1979-01-01

A radioimmunoassay (RIA) has been developed for the determination of antithrombin III (AT III) in man. The detection limit was 25 μg/dl. At III-RIA level and biological activity (anti-Xa) was significantly correlated (r = 0.737, P < 0.0001). Plasma levels in 36 healthy males (mean +- SD, 19.9 +- 2.5 mg/dl) and 21 healthy females (19.1 +- 2.4 mg/dl) were similiar. Serial AT III measurements in normal menstruating females showed lower levels during midcycle and higher concentrations during menstruation. In carcinomas, the AT III levels were lower than normal, particularly in hepatocellular carcinoma. In cirrhosis of liver, the levels were markedly decreased and in some patients were below that found in congenital AT III deficiency. Patients with deep vein thrombosis and patients with heart valve replacement had lower levels than normal, while patients with cerebral vascular occlusion had normal levels. The possible use of AT III as a diagnostic tool of post-operative deep vein thrombosis was demonstrated in one patient after hysterectomy. The increased sensitivity, specificity and precision of this type of assay offer distinct advantages over existing methods of AT III estimation. (author)

Radioimmunoassay in children with glomerulonephritis

International Nuclear Information System (INIS)

Ametov, A.S.; Gavryushova, L.P.; Shashinka, M.; Mumladze, Eh.B.; Tvorogova, T.M.; Dakhuk, B.; Dronova, V.I.; Toritsina, D.K.; Petrova, T.V.

1985-01-01

Proceeding from a radioimmunoassay of various biologically active substances in the blood and urine (ACTH, cortisol, FSH, LH, prolatin, progesterone, estradiol, plasma renin activity and β 2 -microglobulin) of 220 children with glomerulonephritis change of all indices with relation to the type and gravity of glomerulonephritis as well as renal function was revealed. The nature of influence on corticosteroid and immunosuppressive therapy was shown. The authors consider it appropriate to use the determination of biologically active substances in the blood and urine for a more profound estimation of a child's status

Quick insulin radioimmunoassay and its utilization for intra operative localization of insulinoma

International Nuclear Information System (INIS)

Ursich, M.J.M.; Fukui, R.T.; Aguiar Pupo, A. de; Machado, M.C.C.

1988-01-01

A quick insuLin radioimmunoassay performed in 90 minutes is described and the results are compared with those obtained with the conventional method. The realibility of the new procedure is pointed. (M.A.C.) [pt

Effects of phosphodiesterase inhibitors on atrial dynamics induced by C-type natriuretic peptide in isolated beating rabbit atria

International Nuclear Information System (INIS)

Ding Dazhi; Cui Xun; Jin Xiunan; Lan Ying; Liu Liping; Hong Lan

2010-01-01

Objective: To investigate the effects of phosphodiesterase inhibitors (PDEI) on atrial dynamics induced by C-type natriuretic peptide (CNP) and the contents of cyclic nucleotide (cAMP, cGMP) in isolated beating rabbit atria. Methods: After the rabbits had been anesthetized, the hearts were removed rapidly. The left auricles were isolated and fixed on the atrial perfusion system. The atrial stroke volume and the pulse pressure were observed by CNP with or without PDEIs pretreatment. The contents of cAMP and cGMP were measured by radioimmunoassay. Results: (1)Compared with control cycle group, CNP (30.0 nmol · L -1 ) obviously decreased the atrial stroke volume and pulse pressure (P 0.05). (2)Compared with control cycle group, IBMX(1000.0 nmol · L -1 ), a non-selective inhibitor of PDE, significantly increased the atrial stroke volume, pulse pressure, cAMP and cGMP contents (P -1 ) plus CNP (30.0 nmol · L -1 )group and IBMX group (P>0.05). (3)Compared with control cycle group, EHNA(30.0 nmol · L -1 ), an inhibitor of PDE2, obviously decreased the atrial stroke volume and pulse pressure (P 0.05). EHNA(30.0 nmol · L -1 ) plus CNP (30.0 nmol · L -1 ) showed similar roles with EHNA only. (4)Compared with control cycle group, milrinone (1.0 nmol · L -1 ), an inhibitor of PDE3, significantly increased the content of cAMP (P 0.05). CNP (30.0 nmol · L -1 ) obviously decreased the atrial stroke volume and pulse pressure (P 0.05). Conclusion: CNP can inhibit atrial dynamics by increasing the content of cGMP, the different inhibitors of PDEs play different roles in the CNP-induced inhibition of atrial dynamics in isolated beating rabbit atria. (authors)

Urinary osteocalcin and serum pro-C-type natriuretic peptide predict linear catch-up growth in infants

DEFF Research Database (Denmark)

Kilpeläinen, Leena; Ivaska, Kaisa K; Kuiri-Hänninen, Tanja

2012-01-01

of this longitudinal study was to determine the extent to which postnatal levels of circulating cartilage (serum pro-C-type natriuretic peptide [S-proCNP]) and urinary bone metabolic markers (urinary osteocalcin [MidOC] and two forms of C-terminal cross-linked telopeptide of type I collagen [U-α-CTX-I and U...

Improved radioimmunoassay of plasma cortisol

International Nuclear Information System (INIS)

Donohue, J.; Sgoutas, D.

1975-01-01

We report a simplified radioimmunoassay procedure for determination of plasma cortisol. The method offers the advantage that tracer, antibody, and assay buffer are added in a single step with the use of semi-automated equipment. Thus, critical pipetting procedures are minimized, and assay time is reduced to 4 h. No prior extraction or chromatographic purification of cortisol is required. The procedure is simple, reliable, and accurate. For either between-assay or within-assay determinations, the coefficients of variation are about 6 percent. Our results compare well with those obtained from a procedure that included extraction and chromatographic purification of cortisol in several plasma samples. Conditions for optimizing the assay are also discussed. (auth)

Zein nanoparticle as a novel BMP6 derived peptide carrier for enhanced osteogenic differentiation of C2C12 cells.

Science.gov (United States)

Hadavi, Mahvash; Hasannia, Sadegh; Faghihi, Shahab; Mashayekhi, Farhad; Homazadeh, Homayoun; Mostofi, Seyed Behrooz

2018-01-26

Zein nanoparticles as a carrier system for BMP6-derived peptide were prepared by liquid-liquid phase separation procedure and characterized with SEM, DLS, FTIR and thermogravimetric methods. After peptide encapsulation, nanoparticle size increased from 236.3 ± 92.2 nm to 379.4 ± 116.8 nm. The encapsulation efficiency of peptide was 72.6% and the release of peptide from Zein nanoparticles was partly sustained in trypsin containing phosphate buffered saline (pH 7.4) for up to 14 days. Peptide-loaded nanoparticles showed similar cell viability compared with blank ones. ALP activity of C2C12 cells treated with peptide-loaded nanoparticles (500 µg/mL) was evaluated 7, 14, 21 and 28 days after culture. In peptide-loaded nanoparticles, ALP activity was significantly higher (p < .05) compared with other groups at day 14. Alizarin Red S staining showed, C2C12 cells behind peptide-loaded nanoparticles had significantly (p < .05) higher calcium deposition at day 21. The results of RT-qPCR show that the BMP-6 peptide activated expression of RUNX2 as a transcription factor. In turn, RUNX2 regulates SPP1 and BGLAP gene expression, as osteogenic marker genes. The results confirm that the peptide-loaded Zein nanoparticles, as osteoinductive material, may be used to repair small area of bone defects, with low load bearing.

Amyloid fibril formation of peptides derived from the C-terminus of CETP modulated by lipids

Energy Technology Data Exchange (ETDEWEB)

García-González, Victor [Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 México, DF (Mexico); Mas-Oliva, Jaime, E-mail: jmas@ifc.unam.mx [Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 México, DF (Mexico); División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510 México, DF (Mexico)

2013-04-26

Highlights: •The secondary structure of a C-terminal peptide derived from CETP was studied. •Lipids modulate secondary structure changes of a C-terminal peptide derived from CETP. •Lysophosphatidic acid maintains a functional α-helix and prevents fibril formation. •Transfer of lipids by CETP is related to the presence of an α-helix at its C-end. -- Abstract: Cholesteryl-ester transfer protein (CETP) is a plasmatic protein involved in neutral lipid transfer between lipoproteins. Focusing on the last 12 C-terminus residues we have previously shown that mutation D{sub 470}N promotes a conformational change towards a β-secondary structure. In turn, this modification leads to the formation of oligomers and fibrillar structures, which cause cytotoxic effects similar to the ones provoked by amyloid peptides. In this study, we evaluated the role of specific lipid arrangements on the structure of peptide helix-Z (D{sub 470}N) through the use of thioflavin T fluorescence, peptide bond absorbance, circular dichroism and electron microscopy. The results indicate that the use of micelles formed with lysophosphatidylcholine and lysophosphatidic acid (LPA) under neutral pH induce a conformational transition of peptide helix-Z containing a β-sheet conformation to a native α-helix structure, therefore avoiding the formation of amyloid fibrils. In contrast, incubation with phosphatidic acid does not change the profile for the β-sheet conformation. When the electrostatic charge at the surface of micelles or vesicles is regulated through the use of lipids such as phospholipid and LPA, minimal changes and the presence of β-structures were recorded. Mixtures with a positive net charge diminished the percentage of β-structure and the amount of amyloid fibrils. Our results suggest that the degree of solvation determined by the presence of a free hydroxyl group on lipids such as LPA is a key condition that can modulate the secondary structure and the consequent formation of

Amyloid fibril formation of peptides derived from the C-terminus of CETP modulated by lipids

International Nuclear Information System (INIS)

García-González, Victor; Mas-Oliva, Jaime

2013-01-01

Highlights: •The secondary structure of a C-terminal peptide derived from CETP was studied. •Lipids modulate secondary structure changes of a C-terminal peptide derived from CETP. •Lysophosphatidic acid maintains a functional α-helix and prevents fibril formation. •Transfer of lipids by CETP is related to the presence of an α-helix at its C-end. -- Abstract: Cholesteryl-ester transfer protein (CETP) is a plasmatic protein involved in neutral lipid transfer between lipoproteins. Focusing on the last 12 C-terminus residues we have previously shown that mutation D 470 N promotes a conformational change towards a β-secondary structure. In turn, this modification leads to the formation of oligomers and fibrillar structures, which cause cytotoxic effects similar to the ones provoked by amyloid peptides. In this study, we evaluated the role of specific lipid arrangements on the structure of peptide helix-Z (D 470 N) through the use of thioflavin T fluorescence, peptide bond absorbance, circular dichroism and electron microscopy. The results indicate that the use of micelles formed with lysophosphatidylcholine and lysophosphatidic acid (LPA) under neutral pH induce a conformational transition of peptide helix-Z containing a β-sheet conformation to a native α-helix structure, therefore avoiding the formation of amyloid fibrils. In contrast, incubation with phosphatidic acid does not change the profile for the β-sheet conformation. When the electrostatic charge at the surface of micelles or vesicles is regulated through the use of lipids such as phospholipid and LPA, minimal changes and the presence of β-structures were recorded. Mixtures with a positive net charge diminished the percentage of β-structure and the amount of amyloid fibrils. Our results suggest that the degree of solvation determined by the presence of a free hydroxyl group on lipids such as LPA is a key condition that can modulate the secondary structure and the consequent formation of amyloid

Radioimmunoassay in microtiter plates

International Nuclear Information System (INIS)

Hirschberg, T.; Hirschberg, H.

1987-01-01

A radioimmunoassay was performed in the wells of casein-coated microplates employing 125 I-labelled sheep anti-human second antibody. The antigen-antibody complexes were thereafter dislodged from the well walls using detergent sodium dodecyl sulfate (SDS) and the entire contents of the wells were simultaneously absorbed into 48 cellulose acetate-absorbing cartridges. All 48 cartridges were transferred to counting vials and the radioactivity determined by standard gamma counting techniques. The particular advantage of the method described here is the ease with which the supernatants can be collected and transferred to counting vials with minimal handling of radioactive samples. 6 refs.; 1 figure; 1 table

A radioimmunoassay for anti-virus antibodies in farm animals

International Nuclear Information System (INIS)

Rodak, L.; Smid, B.; Sedlacek, M.

1978-01-01

A radioimmunoassay for determination of antibodies to Aujeszky's disease virus in piq serum is described. The results show a number of advantaqes of this method over the routinely employed virus-neutralization test. The possibility of using the RIA method in diagnosing other viral diseases of farm animals is suggested. (authors)

Phase behavior and nanoscale structure of phospholipid membranes incorporated with acylated C-14-peptides

DEFF Research Database (Denmark)

Pedersen, T.B.; Kaasgaard, Thomas; Jensen, M.O.

2005-01-01

The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated...... peptide, which is a synthetic decapeptide N-terminally linked to a C-14 acyl chain (C-14-peptide), is incorporated into DPPC bilayers in amounts ranging from 0-20 mol %. The calorimetric scans of the two-component system demonstrate a distinct influence of the C-14-peptide on the lipid bilayer...... gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C-14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10...

DNA methylation mediates the effect of maternal cognitive appraisal of a disaster in pregnancy on the child's C-peptide secretion in adolescence: Project Ice Storm.

Directory of Open Access Journals (Sweden)

Lei Cao-Lei

Full Text Available Animal and human studies suggest that prenatal exposure to stress is associated with adverse health outcomes such as type 2 diabetes. Epigenetic modification, such as DNA methylation, is considered one possible underlying mechanism. The 1998 Quebec ice storm provides a unique opportunity to study an independent prenatal stressor on child outcomes. C-peptide is the best measure of endogenous insulin secretion and is widely used in the clinical management of patients with diabetes. The objectives of this study are to determine 1 the extent to which prenatal exposure to disaster-related stress (maternal objective hardship and maternal cognitive appraisal influences children's C-peptide secretion, and 2 whether DNA methylation of diabetes-related genes mediates the effects of prenatal stress on C-peptide secretion. Children's (n = 30 C-peptide secretion in response to an oral glucose tolerance test were assessed in blood at 13½ years. DNA methylation levels of selected type 1 and 2 diabetes-related genes were chosen based upon the genes associated with prenatal maternal objective hardship and/or cognitive appraisal levels. Bootstrapping analyses were performed to determine the mediation effect of DNA methylation. We found that children whose mothers experienced higher objective hardship exhibited higher C-peptide secretion. Cognitive appraisal was not directly associated with C-peptide secretion. DNA methylation of diabetes-related genes had a positive mediation effect of objective hardship on C-peptide secretion: higher objective hardship predicted higher C-peptide secretion through DNA methylation. Negative mediation effects of cognitive appraisal were observed: negative cognitive appraisal predicted higher C-peptide secretion through DNA methylation. However, only one gene, LTA, remained a significant mediator of cognitive appraisal on C-peptide secretion after the conservative Bonferroni multiple corrections. Our findings suggest that DNA

Conformational determinants of phosphotyrosine peptides complexed with the Src SH2 domain.

Directory of Open Access Journals (Sweden)

Joseph Nachman

2010-06-01

Full Text Available The inhibition of specific SH2 domain mediated protein-protein interactions as an effective chemotherapeutic approach in the treatment of diseases remains a challenge. That different conformations of peptide-ligands are preferred by different SH2 domains is an underappreciated observation from the structural analysis of phosphotyrosine peptide binding to SH2 domains that may aid in future drug design. To explore the nature of ligand binding, we use simulated annealing (SA to sample the conformational space of phosphotyrosine-containing peptides complexed with the Src SH2 domain. While in good agreement with the crystallographic and NMR studies of high-affinity phosphopeptide-SH2 domain complexes, the results suggest that the structural basis for phopsphopeptide- Src SH2 interactions is more complex than the "two-pronged plug two-hole socket" model. A systematic study of peptides of type pYEEX, where pY is phosphotyrosine and X is a hydrophobic residue, indicates that these peptides can assume two conformations, one extended and one helical, representing the balance between the interaction of residue X with the hydrophobic hole on the surface of the Src SH2 domain, and its contribution to the inherent tendency of the two glutamic acids to form an alpha-helix. In contrast, a beta-turn conformation, almost identical to that observed in the crystal structure of pYVNV bound to the Grb2 SH2 domain, predominates for pYXNX peptides, even in the presence of isoleucine at the third position. While peptide binding affinities, as measured by fluorescence polarization, correlate with the relative proportion of extended peptide conformation, these results suggest a model where all three residues C-terminal to the phosphotyrosine determine the conformation of the bound phosphopeptide. The information obtained in this work can be used in the design of specific SH2 domain inhibitors.

Detection of human spermatozoal peptides after conjugation to 125I-labelled human serum albumin

International Nuclear Information System (INIS)

Metler, L.; Skrabei, H.; Czuppon, A.B.

1981-01-01

Human spermatozoal peptides, liberated during autolysis of the cells, were fractionated by gel-filtration chromatography and thin-layer chromatography. After conjugation to 125 I-labelled human serum albumin, all fractions were assayed with rabbit antihuman spermatozoa antiserum. In earlier publications, human sperm-immobilizing and sperm-agglutinating sera were used for the detection of solubilized spermatozoal antigen. The low sensitivity of these tests necessitated a more sensitive test. The purpose of this work is to describe a solid-phase radioimmunoassay for the detection of antigenic peptides

Radioimmunoassay of methaqualone in human urine compared with chromatographic methods

International Nuclear Information System (INIS)

Mule, S.J.; Kogan, M.; Jukofsky, D.

1978-01-01

The 125 I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 μg of methaqualone per liter of urine. The coefficient of variation was 2.88 -+ 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P < 0.001). Comparisons between the thin-layer chromatographic data and the gas--liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter techniques. Gas--liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine

Radioimmunoassay method for detection of gonorrhea antibodies

International Nuclear Information System (INIS)

1975-01-01

A novel radioimmunoassay for the detection of gonorrhea antibodies in serum is described. A radionuclide is bound to gonorrhea antigens produced by a growth culture. In the presence of gonorrhea antibodies in the serum, an antigen-antibody conjugate is formed, the concentration of which can be measured with conventional radiometric methods. The radioimmunoassay is highly specific

Determination of antioxidant activity of bioactive peptide fractions obtained from yogurt.

Science.gov (United States)

Aloğlu, H Sanlıdere; Oner, Z

2011-11-01

In this study, physicochemical and microbiological properties of traditional and commercial yogurt samples were determined during 4 wk of storage. Proteolytic activity, which occurs during the storage period of yogurt samples, was also determined. Peptide fractions obtained from yogurts were investigated and the effect of proteolysis on peptide release during storage was determined. The antioxidant activities of peptides released from yogurt water-soluble extracts (WSE) and from HPLC fractions were determined by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The antioxidant activity of WSE from traditional yogurt was greater than that of WSE from commercial yogurts. In analysis by the ABTS method, mean values increased from 7.697 to 8.739 mM Trolox/g in commercial yogurts, and from 10.115 to 13.182 mM Trolox/g in traditional yogurts during storage. Antioxidant activities of peptides released from HPLC fractions of selected yogurt samples increased 10 to 200 times. In all yogurt samples, the greatest antioxidant activity was shown in the F2 fraction. After further fractionation of yogurt samples, the fractions coded as F2.2, F2.3, F4.3, and F4.4 had the highest antioxidant activity values. Total antioxidant activity of yogurts was low but after purification of peptides by fractionation in HPLC, peptide fractions with high antioxidant activity were obtained. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Radioimmunoassay of follicle stimulating hornone in human plasma

International Nuclear Information System (INIS)

Akande, E.O.

1976-01-01

A radioimmunoassay method for Follicle Stimulating Hormone (fsh) in human plasma is described. The method proved to be reliable in determining fsh levels in normally menstruating women as well as women in varying clinical states. The patterns and levels of fsh obtained from 16 menstrual cycles in 12 normally menstruating women showed agreement with previous results of Franchimont, Faiman and Ryan, etc

Solid phase separation technique for use in radioimmunoassays

International Nuclear Information System (INIS)

Tu, J.I.

1979-01-01

A radioimmunoassay procedure, and article of manufacture for carrying out that procedure, are disclosed herein. The solid phase separation technique utilized in the radioimmunoassay of this invention utilizes a test tube, the internal surface of which has been coated with two antibody layers

Determination of progesterone for reproduction control in cows using a 3H radioimmunoassay. 1

International Nuclear Information System (INIS)

Taubert, H.; Barth, T.; Hempel, G.; Graeser, K.

1984-01-01

For verification of cow fertility a 3 H radioimmunoassay of progesterone in milk and blood plasma was developed. It is of high specificity and accuracy as well. Extraction of progesterone from milk was facilitated by application of alcohol. Suggested differences in milk and plasma progesterone levels between pregnant and nonpregnant cows could be revealed

A family of cell-adhering peptides homologous to fibrinogen C-termini

International Nuclear Information System (INIS)

Levy-Beladev, Liron; Levdansky, Lilia; Gaberman, Elena; Friedler, Assaf; Gorodetsky, Raphael

2010-01-01

Research highlights: → Cell-adhesive sequences homologous to fibrinogen C-termini exist in other proteins. → The extended homologous cell-adhesive C-termini peptides family is termed Haptides. → In membrane-like environment random coiled Haptides adopt a helical conformation. → Replacing positively charged residues with alanine reduces Haptides activity. -- Abstract: A family of cell-adhesive peptides homologous to sequences on different chains of fibrinogen was investigated. These homologous peptides, termed Haptides, include the peptides Cβ, preCγ, and CαE, corresponding to sequences on the C-termini of fibrinogen chains β, γ, and αE, respectively. Haptides do not affect cell survival and rate of proliferation of the normal cell types tested. The use of new sensitive assays of cell adhesion clearly demonstrated the ability of Haptides, bound to inert matrices, to mediate attachment of different matrix-dependent cell types including normal fibroblasts, endothelial, and smooth muscle cells. Here we present new active Haptides bearing homologous sequences derived from the C-termini of other proteins, such as angiopoietin 1 and 2, tenascins C and X, and microfibril-associated glycoprotein-4. The cell adhesion properties of all the Haptides were found to be associated mainly with their 11 N-terminal residues. Mutated preCγ peptides revealed that positively charged residues account for their attachment effect. These results suggest a mechanism of direct electrostatic interaction of Haptides with the cell membrane. The extended Haptides family may be applied in modulating adhesion of cells to scaffolds for tissue regeneration and for enhancement of nanoparticulate transfection into cells.

A short synthetic peptide fragment of human C2ORF40 has therapeutic potential in breast cancer

Energy Technology Data Exchange (ETDEWEB)

Lin, Chaoyang [Shandong Univ., Jinan (China); Zhang, Pengju [Shandong Univ., Jinan (China); Jiang, Anli [Shandong Univ., Jinan (China); Mao, Jian-Hua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wei, Guangwei [Shandong Univ. School of Medicine, Jinan (China)

2017-03-30

C2ORF40 encodes a secreted protein which is cleaved to generate soluble peptides by proteolytic processing and this process is believed to be necessary for C2ORF40 to exert cell type specific biological activity. Here, we reported a short mimic peptide of human C2ORF40 acts potential therapeutic efficacy in human cancer cells in vitro and in vivo. We synthesized a short peptide of human C2ORF40, named C2ORF40 mimic peptide fragment and assessed its biological function on cancer cell growth, migration and tumorigenesis. Cell growth assay showed that C2ORF40 mimic peptide fragment significantly suppressed cell proliferation of breast and lung cancer cells. Moreover, C2ORF40 mimic peptide fragment significantly inhibited the migration and invasion of breast cancer cells. Furthermore, we showed that this peptide suppressed tumorigenesis in breast tumor xenograft model. Cell cycle assay indicated that the C2ORF40 mimic peptide fragment suppressed the growth of tumor cells through inducing mitotic phase arrest. In conclusion, our results firstly suggested that this short synthetic peptide of human C2ORF40 may be a candidate tumor therapeutic agent.

HBsAg d and y subtypes determined by inhibition radio-immunoassay

Energy Technology Data Exchange (ETDEWEB)

Wilkinson, R [Border Blood Transfusion Service, East London (South Africa)

1981-12-01

An inhibition radioimmunoassay for the detection of HBsAg/d and HBsAg/y antigens is described. A survey of 211 asymptomatic HBsAg positive blood donors showed 190 to be of type HBsAg/d and 3 to be of type HBsAg/y, while the remaining 18 could not be typed. Of 43 patients with acute hepatitis 39 were type HBsAg/d and 4 were type HBsAg/y. The statistically significant (p smaller than 0,01) increase in type HBsAg/y may reflect a changing pattern in offending viral strain with the passage of time.

Presence of melatonin in various cat brainstem nuclei determined by radioimmunoassay

International Nuclear Information System (INIS)

Sallanon, M.; Touret, M.; Claustrat, B.

1982-01-01

Microdissected samples of juvenile cat brain tissue were assayed for melatonin content using a double antibody radioimmunoassay. Immunoreactive melatonin was consistently detected, albeit in variable amounts, in pineal, habenula, the region of the nucleus gracilis, gigantocellular reticular formation of the pons and medulla oblongata. Among the negative areas were raphe nuclei, substantia nigra dn locus caeruleus. These findings suggest that melatonin may play a role in some structures of the central nervous system outside the pineal-hypothalamo-pituitary axis. This immunoreactive melatonin could reflect a local synthesis, or a tissular uptake of melatonin from blood or cerebrospinal fluid. (author)

Determination of polycyclic aromatic hydrocarbons in urine from coke-oven workers with a radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Herikstad, B.V.; Ovrebo, S.; Haugen, A.; Hagen, I. (Center for Industrial Research, Oslo (Norway))

1993-02-01

Considerable amounts of polycyclic aromatic hydrocarbons (PAH) are present in the workplace. In order to obtain a better understanding of the occupational hazards connected with PAH exposure various biomonitoring methods need to be applied. The level of PAH in urine collected from coke-oven workers has been measured by a recently developed radioimmunoassay. A significant correlation between estimated exposure levels for PAH and urinary levels of PAH was observed. During the winter period the control group was found to have an average concentration of 0.44 ng PAH/mmol creatinine, whereas the low, medium and high exposure groups contained 0.44, 0.71 and 0.85 ng PAH/mmol creatinine respectively. The urinary PAH level in the samples collected during the summer period was higher, i.e. 0.81, 0.94 and 1.10 ng PAH/mmol creatinine, for the low, medium and high exposure groups. Furthermore, a correlation was also observed between smoking and levels of urinary PAH. We conclude that this radioimmunoassay may be suitable as a simple and sensitive routine assay for monitoring individuals exposed to PAH.

C-terminal peptides of tissue factor pathway inhibitor are novel host defense molecules.

Science.gov (United States)

Papareddy, Praveen; Kalle, Martina; Kasetty, Gopinath; Mörgelin, Matthias; Rydengård, Victoria; Albiger, Barbara; Lundqvist, Katarina; Malmsten, Martin; Schmidtchen, Artur

2010-09-03

Tissue factor pathway inhibitor (TFPI) inhibits tissue factor-induced coagulation, but may, via its C terminus, also modulate cell surface, heparin, and lipopolysaccharide interactions as well as participate in growth inhibition. Here we show that C-terminal TFPI peptide sequences are antimicrobial against the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungi Candida albicans and Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen for the "classic" human antimicrobial peptide LL-37. The killing of E. coli, but not P. aeruginosa, by the C-terminal peptide GGLIKTKRKRKKQRVKIAYEEIFVKNM (GGL27), was enhanced in human plasma and largely abolished in heat-inactivated plasma, a phenomenon linked to generation of antimicrobial C3a and activation of the classic pathway of complement activation. Furthermore, GGL27 displayed anti-endotoxic effects in vitro and in vivo in a mouse model of LPS shock. Importantly, TFPI was found to be expressed in the basal layers of normal epidermis, and was markedly up-regulated in acute skin wounds as well as wound edges of chronic leg ulcers. Furthermore, C-terminal fragments of TFPI were associated with bacteria present in human chronic leg ulcers. These findings suggest a new role for TFPI in cutaneous defense against infections.

Quantitative kinetics of proteolytic enzymes determined by a surface concentration-based assay using peptide arrays.

Science.gov (United States)

Jung, Se-Hui; Kong, Deok-Hoon; Park, Seoung-Woo; Kim, Young-Myeong; Ha, Kwon-Soo

2012-08-21

Peptide arrays have emerged as a key technology for drug discovery, diagnosis, and cell biology. Despite the promise of these arrays, applications of peptide arrays to quantitative analysis of enzyme kinetics have been limited due to the difficulty in obtaining quantitative information of enzymatic reaction products. In this study, we developed a new approach for the quantitative kinetics analysis of proteases using fluorescence-conjugated peptide arrays, a surface concentration-based assay with solid-phase peptide standards using dry-off measurements, and compared it with an applied concentration-based assay. For fabrication of the peptide arrays, substrate peptides of cMMP-3, caspase-3, caspase-9, and calpain-1 were functionalized with TAMRA and cysteine, and were immobilized onto amine-functionalized arrays using a heterobifunctional linker, N-[γ-maleimidobutyloxy]succinimide ester. The proteolytic activities of the four enzymes were quantitatively analyzed by calculating changes induced by enzymatic reactions in the concentrations of peptides bound to array surfaces. In addition, this assay was successfully applied for calculating the Michaelis constant (K(m,surf)) for the four enzymes. Thus, this new assay has a strong potential for use in the quantitative evaluation of proteases, and for drug discovery through kinetics studies including the determination of K(m) and V(max).

Somatomedin A in human serum: determined by radioimmunoassay and radioreceptorassay; results and implications

International Nuclear Information System (INIS)

Hall, K.; Sara, V.

1981-01-01

The polypeptide hormones in the somatomedin family were discovered as three different biological activities of serum: insulin-like activity (ILA), sulphation factor activity (SFA) and multiplication stimulatory activity (MSA). Three different biological actions on three different target tissues have been used to identify the somatomedins during their purification. All the somatomedins contain ILA, SFA and MSA but their order of potency of biological action varies from tissue to tissue. It is apparent that the pattern of somatomedin levels determined throughout human life varies according to the technique used for their determination. Each assay has a unqiue order of crossreaction for the various somatomedins, and is sensitive to different forms present in blood. Thus the different patterns must reflect the predominance of specific somatomedins at certain stages of life. The heterogeneity of polypeptide hormones in the circulating blood is well recognized but its relation to age and development has yet to be fully explored. Methods for the estimation of the somatomedins must take account of such differences. In the radioimmunoassay field it is generally recognized that each type of antibody has a unique recognition pattern. This applies equally to the radioreceptorassay where the specificity of the receptor varies according to species, organ and age. Consequently, it is essential that age-related standards are established for each technique for the determination of somatomedins. (Auth.)

Radioimmunoassay of capsular polysaccaride antigens of groups A and C meningococci and Haemophilus influenza type b in cerebrospinal fluid

International Nuclear Information System (INIS)

Kaeyhty, H.; Maekelae, P.H.; Ruoslahti, E.

1977-01-01

Sensitive radioimmunoassays capable of measuring 0.5 ng/ml of the Haemophilus influenza type b polysaccharide and 2 ng/ml of the groups A and C meningococcal polysaccharides were developed and used to detect these substances in cerebrospinal fluid (CSF). Polysaccharide of the causative agent was detected in the CSF of 14 out of 15 patients with Haemophilus influenza type b meningitis, in 18 out of 23 patients with group A, and in two out of four patients with group C meningococcal meningitis. In some cases the antigen could be detected even after three days of antibacterial treatment. No false positive reactions were seen. The assay procedure could be shortened to approximately three hours. These assays could be useful in routine diagnostic work and epidemiological investigations. (author)

Radioimmunoassay to quantitatively measure cell surface immunoglobulins

International Nuclear Information System (INIS)

Krishman, E.C.; Jewell, W.R.

1975-01-01

A radioimmunoassay techniques developed to quantitatively measure the presence of immunoglobulins on the surface of cells, is described. The amount of immunoglobulins found on different tumor cells varied from 200 to 1140 ng/10 6 cells. Determination of immunoglobulins on the peripheral lymphocytes obtained from different cancer patients varied between 340 to 1040 ng/10 6 cells. Cultured tumor cells, on the other hand, were found to contain negligible quantities of human IgG [pt

Quality control of radioiodinated gastrin for radioimmunoassay

International Nuclear Information System (INIS)

Ginabreda, M.G.P.; Borghi, V.C.; Bettarello, A.

1988-07-01

Radioiodinated human gastrin has been prepared at IPEN laboratory for radioimmunoassay use. This work developed the quality control of this tracer analyzing parameters of the labelling reaction, chromatographic purification and radioimmunoassay. The radioiodination yield obtained in five experiments was reproducible and similar when analyzed on 7% polyaraylamide gel eletrophoresis - PAGE - (mean + - SD of 51.70 + - 10.76%) and by1 25 I incorporation checked through thrichloroacetic acid precipitation - TCA - (57-36 + - 9.69%). Similary, after purification the labelled gastrin revaled high and reproducible purity degree when submitted to PAGE (96.57 + - 1.06%) and CA (94.82 + - 4.20%) analysis. The respective specific activities varied from 62 to 307 uCi/ug, being determined by the self-displacement method, which is based on the immunoactivity of the tracer. In this way, the antibody titers required to bind 50% of the tracer ranged from 1:32.000 to 1:180.000. Consequently, the respective doses producing 50% fall in the maximum response of the radioimmunoassays ranged from 155.0 to 24.0 pmol/1, but remained unchanged for each tracer even after three months of its preparations. The tracers presented very low non-specific binding values (1.78 + - 0.79%), stablespecific binding values (46.49 + - 5.65%) and a good between-assay precision, evaluated by an internal quality control sample (25.71 + - 4.30%) with coefficient of variation of 16.74%). The PAGE analysis of the unlabeled gastrin used in the first and last radioiodination revealed an unique and unaltered component, confirming the quality of the tracers. (author) [pt

Evaluation of extraction methods for progesterone determination in rabbit (Oryctolagus cuniculus) feces by radioimmunoassay

International Nuclear Information System (INIS)

Korndoerfer, Clotilde Maria; Meirelles, Cyro Ferreira; Bueno, Ives Claudio da Silva; Abdalla, Adibe Luiz

1998-01-01

The purpose of this study was to find a practical procedure for the extraction of progesterone (P 4 ) from feces and to determine if the P4 plasma profiles during pregnancy were reflected in total fecal P4 of pregnant rabbits. The rabbit was used as model for the techniques. Plasma and feces were collected from 11 rabbits during a period of 42 days. Three different methods of P4 extraction were used. The total P4 was measured by solid-phase radioimmunoassay (RIA) with 125 I-P4 as the tracer. Results suggested that it was possible to extract total P4 from rabbit feces with methanol and petroleum ether. Plasma and fecal P4 profiles were compared for both pregnant and ovariectomized rabbits. It was possible to differentiate total P4 extracted from day two through 28 after breeding (p<0.01). (author)

Evaluation of extraction methods for progesterone determination in rabbit (Oryctolagus cuniculus) feces by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Korndoerfer, Clotilde Maria; Meirelles, Cyro Ferreira; Bueno, Ives Claudio da Silva; Abdalla, Adibe Luiz [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Secao de Ciencias Animais]. E-mail: cfmeirel@esalq.usp.br

1998-07-01

The purpose of this study was to find a practical procedure for the extraction of progesterone (P{sub 4}) from feces and to determine if the P4 plasma profiles during pregnancy were reflected in total fecal P4 of pregnant rabbits. The rabbit was used as model for the techniques. Plasma and feces were collected from 11 rabbits during a period of 42 days. Three different methods of P4 extraction were used. The total P4 was measured by solid-phase radioimmunoassay (RIA) with {sup 125} I-P4 as the tracer. Results suggested that it was possible to extract total P4 from rabbit feces with methanol and petroleum ether. Plasma and fecal P4 profiles were compared for both pregnant and ovariectomized rabbits. It was possible to differentiate total P4 extracted from day two through 28 after breeding (p<0.01). (author)

An assessment of radioimmunoassay procedures for determination of anti-acetylcholine receptor antibodies in the sera of patients with myasthenia gravis

International Nuclear Information System (INIS)

Carter, B.; Harrison, R.; Lunt, G.G.; Morris, H.; Savage-Marengo, T.; Stephenson, F.A.

1981-01-01

A reproducible radioimmunoassay procedure for the determination of anti-acetylcholine receptor antibodies in the sera of patients with myasthenia gravis is described and examined in detail. The assay combines features of a number of methods previously outlined and allows repeat determinations of antibody titre in a given myasthenic serum sample with coefficient of variation 6%. The mean +- standard deviation for normal human serum anti-acetylcholine receptor antibodies was found by this procedure to be 0.024 +- 0.033 nmol/l α-bungarotoxin binding sites whereas the range for myasthenic patients was 0-139.14 nmol/l with a mean value of 7.55 nmol/l α-bungarotoxin binding sites. (author)

Novel thrombopoietin mimetic peptides bind c-Mpl receptor: Synthesis, biological evaluation and molecular modeling.

Science.gov (United States)

Liu, Yaquan; Tian, Fang; Zhi, Dejuan; Wang, Haiqing; Zhao, Chunyan; Li, Hongyu

2017-02-01

Thrombopoietin (TPO) acts in promoting the proliferation of hematopoietic stem cells and by initiating specific maturation events in megakaryocytes. Now, TPO-mimetic peptides with amino acid sequences unrelated to TPO are of considerable pharmaceutical interest. In the present paper, four new TPO mimetic peptides that bind and activate c-Mpl receptor have been identified, synthesized and tested by Dual-Luciferase reporter gene assay for biological activities. The molecular modeling research was also approached to understand key molecular mechanisms and structural features responsible for peptide binding with c-Mpl receptor. The results presented that three of four mimetic peptides showed significant activities. In addition, the molecular modeling approaches proved hydrophobic interactions were the driven positive forces for binding behavior between peptides and c-Mpl receptor. TPO peptide residues in P7, P13 and P7' positions were identified by the analysis of hydrogen bonds and energy decompositions as the key ones for benefiting better biological activities. Our data suggested the synthesized peptides have considerable potential for the future development of stable and highly active TPO mimetic peptides. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radioimmunoassay with heterologous antibody (hetero-antibody RIA)

International Nuclear Information System (INIS)

Iwasawa, Atsushi; Hayashi, Hiroaki; Itoh, Zen; Wakabayashi, Katsumi

1991-01-01

To develop a homologous radioimmunoassay (RIA) for a hormone of a small or rare animal often meets difficulty in collecting a large amount of purified antigen required for antibody production. On the other hand, to employ a heterologous RIA to estimate the hormone often gives poor sensitivity. To overcome this difficulty, a 'hetero-antibody' RIA was studied. In a hetero-antibody RIA system, a purified preparation of a hormone is used for radioiodination and standardization and a heterologous antibody to the hormone is used for the first antibody. Canine motilin and rat LH were selected as examples, and anti-porcine motilin and anti-hCG, anti-hCGβ or anti-ovine LHβ was used as the heterologous antibody. The sensitivities of the hetero-antibody RIAs were much higher than those of heterologous RIAs in any case, showing that these hetero-antibody RIA systems were suitable for practical use. To clarify the principle of hetero-antibody RIA, antiserum to porcine motilin was fractionated on an affinity column where canine motilin was immobilized. The fraction bound had greater constants of affinity with both porcine and canine motilins than the rest of the antibody fractions. This fraction also reacted with a synthetic peptide corresponding to the C-terminal sequence common to porcine and canine motilins in a competitive binding test with labeled canine motilin. These results suggest that an antibody population having high affinity and cross-reactivity is present in polyclonal antiserum and indicate that the population can be used in hetero-antibody RIA at an appropriate concentration. (author)

Fall in C-Peptide During First 4 Years From Diagnosis of Type 1 Diabetes: Variable Relation to Age, HbA1c, and Insulin Dose.

Science.gov (United States)

Hao, Wei; Gitelman, Steven; DiMeglio, Linda A; Boulware, David; Greenbaum, Carla J

2016-10-01

We aimed to describe the natural history of residual insulin secretion in Type 1 Diabetes TrialNet participants over 4 years from diagnosis and relate this to previously reported alternative clinical measures reflecting β-cell secretory function. Data from 407 subjects from 5 TrialNet intervention studies were analyzed. All subjects had baseline stimulated C-peptide values of ≥0.2 nmol/L from mixed-meal tolerance tests (MMTTs). During semiannual visits, C-peptide values from MMTTs, HbA1c, and insulin doses were obtained. The percentage of individuals with stimulated C-peptide of ≥0.2 nmol/L or detectable C-peptide of ≥0.017 nmol/L continued to diminish over 4 years; this was markedly influenced by age. At 4 years, only 5% maintained their baseline C-peptide secretion. The expected inverse relationships between C-peptide and HbA1c or insulin doses varied over time and with age. Combined clinical variables, such as insulin-dose adjusted HbA1c (IDAA1C) and the relationship of IDAA1C to C-peptide, also were influenced by age and time from diagnosis. Models using these clinical measures did not fully predict C-peptide responses. IDAA1C ≤9 underestimated the number of individuals with stimulated C-peptide ≥0.2 nmol/L, especially in children. Current trials of disease-modifying therapy for type 1 diabetes should continue to use C-peptide as a primary end point of β-cell secretory function. Longer duration of follow-up is likely to provide stronger evidence of the effect of disease-modifying therapy on preservation of β-cell function. © 2016 by the American Diabetes Association.

Validation of a radioimmunoassay for rat insulin

International Nuclear Information System (INIS)

Delattre, E.; Boschero, A.C.

1984-01-01

A methodological approach that permits, in a radioimmunoassay, the evaluation of rat insulin by using bovine insulin as reference is presented. As in general the technics for radioimmunoassay of different substances follow the same principles (competitive inhibition), we believe that the methodology presented here could be used for evaluation of other hormones when the adequated referential, of know biological activity, is not available. (Author) [pt

Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

International Nuclear Information System (INIS)

Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

1978-01-01

Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

Urodilatin. A renal natriuretic peptide

International Nuclear Information System (INIS)

Carstens, Jan

1998-01-01

Development and validation of a radioimmunoassay for endogenous URO in urine and synthetic URO in plasma is described. The first obstacle to overcome was to produce an antibody specific for URO. A polyclonal URO antibody with a cross-reactivity with the structural highly homologous atrial natriuretic peptide (ANP) was developed by immunization of rabbits with the whole URO(95-126). Purification of the polyclonal URO antiserum with CNBr-activated Sepharose affinity chromatography was a simple way of producing a URO-specific antibody without cross-reactivity with ANP analogues. A reliable 125 I-labelled URO tracer was made with the Iodo-Gen method. Prior to the assay, the urine samples were prepared by ethanol with a recovery of unlabelled URO between 80 - 100% and the plasma samples were Sep-Pak C 18 extracted with a recovery of about 50%. The radioimmunoassay is performed in 3 days, using polyethylene glycol for separation. The sensitivity of the assay was improved by sample preparation and concentration, reducing the amount of tracer and late addition, reducing the amount of antibody and increasing the incubation time and lowering the temperature of incubation. The infusion rate of 20 ng URO kg -1 min -1 was most potential and well tolerated in healthy subjects. The short-term natriuretic and diuretic effects were closely associated with a significant diminished sodium reabsorption in the distal nephron. Further studies are needed to exploit the therapeutical potential of URO, for example in patients with sodium-water retaining disorders. The therapeutical dose range will probably be narrow due to the blood pressure lowering effect of URO with infusion rates higher than 20-30 ng kg -1 min -1 . (EHS)

Central effects of some peptide and non-peptide opioids and naloxone on thermoregulation in the rabbit

Science.gov (United States)

Kandasamy, S. B.; Williams, B. A.

1983-01-01

The effects of several peptide and non-peptide opiods and naloxone on induced hyperthermia is studied in rabbits. The effect of tyical mu, kappa, and sigma receptor antagonists (morphine, ketocyclazcine and SKF 10,0 10, 047) and some opioid peptides (Beta-endorphin /BE/, methionine-enkaphalin /ME/, and D-Ala2-methionine-enkaphalin-amide /DAME/ are determined. The role of prostaglandins (PG), cAMP, and norepinephrine (NE) in morphine, BE, and DAME induced hyperthermia is investigated. In addition, the effect of naloxone on pyrogen, arachidonic acid, PGE2, prostacyclin, dibutyryl cAMP, and NE induced hyperthermia is determined. Among other results, it is found that the three receptor antagonists induced hyperthermia in rabbits. BE, ME, and DAME were also found to cause hyperthermia, and it is suggested that they act on the same type of receptor. It is also determined that neither NE nor cAMP is involved in the hyperthermia due to morphine, BE, and DAME. It is suggested that an action of endogenous peptides on naloxone sensitive receptors plays little role in normal thermoregulation or in hyperthermia.

Uranyl Photocleavage of Phosphopeptides Yields Truncated C-Terminally Amidated Peptide Products

DEFF Research Database (Denmark)

Elnegaard, Rasmus L B; Møllegaard, Niels Erik; Zhang, Qiang

2017-01-01

photocleavage reaction of a tetraphosphorylated β-casein model peptide. We show that the primary photocleavage products of the uranyl-catalysed reaction are C-terminally amidated. This could be of great interest to the pharmaceutical industry, as efficient peptide amidation reactions are one of the top...

Diagnosis of prostate cancer using a radioimmunoassay for prostatic acid phosphatase in serum

International Nuclear Information System (INIS)

Lea, O.A.; Hoeisaeter, P.Aa.

1981-01-01

The paper describes the development and evaluation of a specific radioimmunoassay for the determination of prostatic acid phosphatase in serum as a useful aid in the detection of prostatic cancer. (Auth.)

Erythropoietin radioimmunoassay studies

International Nuclear Information System (INIS)

Garcia, J.F.

1982-01-01

A highly sensitive radioimmunoassay capable of measuring erythropoietin concentrations in very small amounts of serum as been developed. After establishing normal human values on a large series of serum samples, serum samples from patients with polycythemia vera and patients with secondary polycythemia were obtained and the erythropoietin concentrations measured

Investigations of serum HPL during pregnancy using two different radioimmunoassays

International Nuclear Information System (INIS)

Stracke, H.

1978-01-01

The interassay investigations showed that it is absolutely necessary to standardize the HPL antisera as well as the standard sera, as it is otherwise impossible to compare and interpret the findings of different HPL radioimmunoassays. The investigations have shown that in addition to conventional clinical examinations and laboratory test methods (urine estriol determination, DHEAS-dehydroepiandrosterone sulphate test-, urine pregnandiol determination, and determination of heat-resisting alkaline serum phosphatase), HPL concentration determination is a parameter of the nutritive function of the placenta. (orig.) [de

Determination of antibody levels to Candida albicans in healthy and hospitalised adults using a radioimmunoassay

International Nuclear Information System (INIS)

Cobb, S.J.; Parratt, D.

1978-01-01

A radioimmunoassay for antibody to Candida albicans is described. The test uses whole, killed of organisms as the antigen and radiolabelled sheep anti-human globulins to quantitate different classes of antibody to C. albicans. The assay has been compared with an Ouchterlony precipitin method and found to be simpler, more rapid, and more sensitive than the latter. Results obtained from two groups of symptomless adults indicated that the range of antibody level was wider for a hospitalised group than for a group of blood transfusion donors, particularly in respect of IgG and IgA antibody. The reason for the increase of antibody in hospital patients was not clear but may have been related to antibiotic therapy. The difficulties in interpretation of Candida serology have therefore been re-assessed in the light of more detailed knowledge of the range and type of antibody to be expected in normal individuals. (author)

Radioimmunoassay and characterization of atrial natriuretic peptide in human plasma

International Nuclear Information System (INIS)

Yandle, T.G.; Espiner, E.A.; Nicholls, M.G.; Duff, H.

1986-01-01

A RIA for alpha-human atrial natriuretic peptide (alpha hANP) in plasma was developed and used to study the immunoreactive components secreted by the heart and circulating in peripheral venous plasma. The assay used [125I]diiodotyrosyl-alpha hANP, purified by high pressure liquid chromatography (HPLC), and a C-terminal-specific antiserum purchased from Peninsula Laboratories. Serial dilution curves of coronary sinus plasma samples were parallel with the standard curve, but significant nonparallelism was found in peripheral plasma samples of low immunoreactivity. When plasma was extracted using C-18 Sep-Pak cartridges, serial dilution curves from both coronary sinus and peripheral plasma samples were parallel to the standard curve. Although values for plasma samples assayed before and after extraction agreed closely (r = 0.99; n = 76), immunoreactive ANP in unextracted plasma was consistently greater (70-79 pmol/liter) than in extracts of plasma, suggesting non-specific interference by a component in plasma when assayed without extraction. Mean plasma immunoreactive ANP in 19 normal subjects consuming a normal salt intake was 14 +/- 1 (+/- SE) pmol/liter. In 5 normal men, increasing dietary sodium intake from 10 to 200 mmol sodium/day was associated with a 2-fold increment in ANP levels, and similar changes accompanied acute sodium loading using iv saline. Elevated values were found in patients with congestive heart failure (mean, 58 pmol/liter; range, 0-200; n = 9), chronic renal failure (mean, 118 pmol/liter; range, 30-290; n = 8), and primary aldosteronism (range, 32-90 pmol/liter; n = 3). HPLC and gel chromatographic analysis of the immunoreactive material found in coronary sinus plasma extracts showed that a large amount of the material eluted in the position of alpha hANP

Basal C-peptide Level as a Surrogate Marker of Subclinical Atherosclerosis in Type 2 Diabetic Patients

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Sung-Tae Kim

2011-02-01

Full Text Available BackgroundRecent studies have revealed that C-peptide induces smooth muscle cell proliferation and causes human atherosclerotic lesions in diabetic patients. The present study was designed to examine whether the basal C-peptide levels correlate with cardiovascular risk in type 2 diabetes mellitus (T2DM patients.MethodsData was obtained from 467 patients with T2DM from two institutions who were followed for four years. The medical findings of all patients were reviewed, and patients with creatinine >1.4 mg/dL, any inflammation or infection, hepatitis, or type 1 DM were excluded. The relationships between basal C-peptide and other clinical values were statistically analyzed.ResultsA simple correlation was found between basal C-peptide and components of metabolic syndrome (MS. Statistically basal C-peptide levels were significantly higher than the three different MS criteria used in the present study, the Adult Treatment Panel III (ATP III of the National Cholesterol Education Program's (NCEP's, World Health Organization (WHO, and the International Diabetes Federation (IDF criteria (NCEP-ATP III, P=0.001; IDF, P<0.001; WHO, P=0.029. The multiple regression analysis between intima-media thickness (IMT and clinical values showed that basal C-peptide significantly correlated with IMT (P=0.043, while the analysis between the 10-year coronary heart disease risk by the United Kingdom Prospective Diabetes Study risk engine and clinical values showed that basal C-peptide did not correlate with IMT (P=0.226.ConclusionBasal C-peptide is related to cardiovascular predictors (IMT of T2DM, suggesting that basal C-peptide does provide a further indication of cardiovascular disease.

Aflatoxin B1 use in radioimmunoassay

International Nuclear Information System (INIS)

Liu Yinkun; Zhang Xiaying; Chen Ruiqun; Gu Tianjue

1987-01-01

Antibodies against Aflatoxin B 1 (AFB 1 ) were obtained after multiple-site injections of bovine serum albumin-AFB 1 conjugate into rabbits. The greatest specific binding effciency of antibody for AFB 1 is 70∼80%. The sensitivity of radioimmunoassay (RIA) for AFB 1 is between 0.46∼2.3 ng. The retrievel rate of AFB 1 by RIA from intentionally contaminated serum and rice is between 70∼80%. Detailed methods for the preparation of conjugate, immune serum, and methods for antibody titer determination are described

Effect of gestational age and blood glucose on C-peptide excretion rate and clearance in neonates.

Science.gov (United States)

Salis, Emma R; Soelbeck, Mikkel K; Reith, David M; Wheeler, Benjamin J; Broadbent, Roland S; Medlicott, Natalie J

2016-01-01

The aim of this study was to measure urinary C-peptide concentrations, and then calculate C-peptide clearance (Cl), and excretion rate (UER) in neonates. In addition, the effect of gestational age (GA) and blood glucose levels (BGL) on C-peptide UER were investigated. Insulin concentrations in plasma and C-peptide concentrations were measured in plasma and urine, in 20 neonates. Chemiluminescent immunoassays were used for insulin and C-peptide measurements, with urine diluted to 40% with bovine serum albumin 1% in phosphate buffered saline. Urine volume and time of collection were recorded and used to calculate UER and Cl. The mean Cl of C-peptide was 0.309 ± 0.329 mL/min/kg, and UER was 0.0329 ± 0.0342 pmol/min/kg. Correlations between Cl or UER and GA were not significant (P > 0.05). No significant correlation was shown between Cl or UER and BGL (P > 0.05). Both Cl and UER were highly variable in neonates, but were not correlated with GA. Additionally, BGL did not appear to affect C-peptide UER and Cl. As GA and BGL did not appear to affect Cl and UER, urinary C-peptide may provide a non-invasive method of measuring insulin production in neonates. © 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Quantitative determination of the organ distribution of the cell adhesion molecule cell-CAM 105 by radioimmunoassay

International Nuclear Information System (INIS)

Odin, P.; Oebrink, B.

1987-01-01

The authors have previously identified a 105,000-Da plasma membrane glycoprotein, denoted cell-CAM 105, that is involved in intercellular adhesion of reaggregating rat hepatocytes. In this communication they report on the development of a radioimmunoassay for cell-CAM 105, employing purified cell-CAM 105, specific antisera against the molecule, and formalin-fixed protein A-containing staphylococci for precipitation of the immune complexes. The assay was shown to be sensitive, specific, precise, rapid, and easy to perform. They used this radioimmunoassay in investigations of the occurrence of cell-CAM 105 in different rat organs. Cell-CAM 105 was present in a wide spectrum of organs in varying amounts. The highest concentrations were found in the gastrointestinal tract, liver, some secretory glands, vagina, kidney, and lung. The results were confirmed by immunoblotting, which revealed one distinct protein component, corresponding to cell-CAM 105, in each positive organ

Secretin-radioimmunoassay, physiology and pathophysiology in man

International Nuclear Information System (INIS)

Haecki, W.H.

1978-01-01

Production of antibodies to secretin for radioimmunoassay is straightforward. Secretin is iodinated by weak oxydation with lactoperoxydase and subsequent purification by ionexchange chromatography (Sephadex C25). The specific activity of fresh label is between 650 and 900 mCi x mol -6 . The label is highly purified and may be used in radioimmunoassay for several months. In order to eliminate plasma interference sepharose-beads with covalently coupled secretin antibodies are used to produce secretin-free standard plasma samples. Delay in the separation of plasma from fresh blood samples can lead to erronous results, even to falsely elevated secretin levels. - Duo-denal acidification only leads to physiological increases of secretin plasma levels. This may happen by intraduodenal instillation of acid, or by an acidic oral drink, or to a lesser extent after a meal. Secretin is distributed throughout the plasma volume and has a short halflife of around 3 minutes. Impaired release of secretin is found in children with coeliac disease. The role of secretin in peptic ulcer however is not clear. Chronic pancreatitis and renal insufficiency are without effect on plasma secretin levels. (orig.) [de

Anti-DNA antibody in serum measured by radioimmunoassay (Farr technique)

Energy Technology Data Exchange (ETDEWEB)

Manthorpe, R; Palit, J; Bendixen, G [Rigshospitalet, Copenhagen (Denmark)

1978-01-01

The anti DNA antibody determination in serum is increasingly used because it supports the diagnosis of systemic lupus erythematosus (SLE) with high selectivity. The present work evaluates several of the technical variables of the Farr radioimmunoassay for anti-DNA antibody determination and describes a recommendable procedure. The most important sources of error are emphasized and the range for normal blood donors and a group of hospital patients without SLE is given.

Anti-DNA antibody in serum measured by radioimmunoassay (Farr technique)

International Nuclear Information System (INIS)

Manthorpe, R.; Palit, J.; Bendixen, G.

1978-01-01

Anti-DNA antibody determination in serums is increasingly used because it supports the diagnosis of systemic lupres erythematosus (SLE) with high selectivity. The present work evaluates several of the technical variables of the Farr radioimmunoassay for anti-DNA antibody determination and describes a recommendable procedure, emphasizes the most important sources of error and gives the range of normal blood donors and a group of hospital patients without SLE. (author)

Development of a radioimmunoassay for papain

International Nuclear Information System (INIS)

Rauch, P.; Fukal, L.; Marek, M.; Strejcek, F.; Kas, J.

1984-01-01

Various well-tried radioimmunoassay (RIA) techniques were compared for the quantitation of papain. The evaluation of individual assays was performed by logit-log analysis. The most compatible analytical steps were combined in order to obtain the optimal analytical conditions of the assay. The preferred RIA involves papain labelling with lactoperoxidase, a double antibody method as the separation step and a 24 h incubation period at 2 0 C. It permits the detection of 16 ng of papain per tube. In contrast, a method using immobilized antibody was satisfactory for rapid quantitation of papain with quite acceptable accuracy. (Auth.)

Radioimmunoassays for catalase and glutathion peroxidase

International Nuclear Information System (INIS)

Baret, A.; Courtiere, A.; Lorry, D.; Puget, K.; Michelson, A.M.

1982-01-01

Specific and sensitive radioimmunoassays for human, bovine and rat catalase (CAT) and glutathion Peroxidase (GPX) are described. The obtained values are expressed as enzymatic units per μg of immunoreactive protein. They appear to closely correspond to specific activities of the purified enzymes determined by colorimetric protein-assay. Indeed, the values of the specific activities of purified human CAT is 57.9 k/mg and that of purified rat GPX is 180 units/mg. This result validates the present RIAs and the association of the two techniques allows the determination of a further parameter. In conclusion, RIAs for CAT and GPX can be applied with great specificity and sensitivity to a wide variety of human, rat and bovine medias

The relationship between C-type natriuretic peptide and cognitive impairment in older patients with Type 2 diabetes

International Nuclear Information System (INIS)

Li Xinling; Zhu Xiangyang; Huang Huaiyu; Jin Yan

2011-01-01

Objective: To investigate the relationship between C-type natriuretic peptide and cognitive impairment in older patients with type 2 diabetes, and to explore the pathogenesis of diabetic cognitive impairment. Methods: According to the Montreal Cognitive Assessment (MoCA) scores, 80 type 2 diabetic patients over the age of 60 years were divided into two groups, one group including 31 cases with cognitive impairment, the other 49 patients with non-cognitive impairment. And 80 normal participants were selected as the control group. Plasma level of C-type natriuretic peptide was measured by radio-immunity assay in all subjects. The changes and associations of the plasma C-type natriuretic peptide level among three groups was analyzed. Result: In the non-cognitive impairment group, plasma level of C-type natriuretic peptide was higher than that in the control group (P<0.01). But the plasma level of C-type natriuretic peptide in the cognitive impairment group was degraded, significantly deferent with those in the control group and the non-cognitive impairment group (P<0.01). MoCA scores of the cognitive impairment group positively correlated with plasma level of C-type natriuretic peptide (r=0.513, P<0.01). Conclusion: In the early period of type 2 diabetes,the secretion of C-type natriuretic peptide was increased. When diabetic cognitive impairment complicated,the secretion of C-type natriuretic peptide was decompensated. Then plasma level of C-type natriuretic peptide become low. The level of C-type natriuretic peptide closely correlated with diabetic cognitive impairment. It was suggested that diabetic angiopathies may act an important role in the pathogenesis of diabetic cognitive impairment. (authors)

Improved radioimmunoassay for thyroid hormone and reagent

International Nuclear Information System (INIS)

1980-01-01

Improvements in the radioimmunoassay of the thyroid hormones, thyroxine or triiodothyronine, are described. Hydrolyzed cross-linked polyacrylamide particles covalently bonded against the thyroid hormone are employed as solid phase substrates for the thyroid hormone antibodies. The polyacrylamide particles are dyed yellow or blue to facilitate the various manipulative steps during the radioimmunoassay. The particles are characterized by their ability to form stable hydrophilic suspensions. As a result the reaction mixture, during which thyroid hormone is separated from serum proteins and competitive binding in the presence of radioactive tracer with the antibody occurs, requires no agitation to maintain the desired homogeneous condition. This is in contrast to the settling problems experienced with cellulose, dextran and glass particles. In addition, the non-specific binding property of the polyacrylamide particles is so low that the initially separated solid phase particles following incubation can be directly measured for radioactivity levels without any initial washings thus increasing the speed and convenience of the assay procedure. Details of the preparation of the dyed, hydrolyzed polyacrylamide particles, the coupling of antiserum to these particles and the radioimmunoassay procedure are given. Data obtained from the radioimmunoassays of hypothyroid, euthyroid and hyperthyroid sera demonstrated the satisfactory performance of the assay. (U.K.)

Measurement of alpha-fetoprotein in maternal serum: three commercial radioimmunoassay kits and two non-commercial radioimmunoassays compared

International Nuclear Information System (INIS)

Forest, J.C.; Verreault, F.; Pouliot, M.

1982-01-01

We evaluated three commercial radioimmunoassay kits (Amersham, Dainabot, Clinical Assays) and two non-commercial methods for determining alpha-fetoprotein in maternal serum during pregnancy. All five procedures were found to be acceptable with respect to practicability, sensitivity, linearity, and precision. Similar results were obtained with Dainabot, Clinical Assays, and the two non-commercial methods, but the Amersham method revealed a proportional error, results being about 20% lower than those by the other methods. Use of the international unit system is suggested for reporting results for AFP, to facilitate comparison between methods and laboratories

Radioimmunoassay of erythropoietin

Energy Technology Data Exchange (ETDEWEB)

Goldwasser, E; Sherwood, J B [Chicago Univ., IL (USA). Dept. of Biochemistry

1981-07-01

A brief review of the historical development of the radioimmunoassay (RIA) for serum erythropoietin is given. It has been shown that there is reasonable agreement between the results obtained by RIA and those obtained by the previously used bioassay. By RIA, a mean normal serum titre of 18 mu/ml erythropoietin has been determined in a study of 445 individuals. Serum erythropoietin results for patients with polycythaemia vera have not been shown to be significantly different from normal values but in patients with secondary polycythaemia, serum titres averaging 94 mu/ml have been found. The predicted physiological changes in erythropoietin titre have also been demonstrated in humans using the RIA; increasing after bleeding and decreasing after red cell administration. Studies of erythropoietin levels in experimental animals have shown that, with the particular antiserum used, the sensitivity of the RIA is markedly reduced.

Assay of mouse-cell clones for retrovirus p30 protein by use of an automated solid-state radioimmunoassay

International Nuclear Information System (INIS)

Kennel, S.J.; Tnnant, R.W.

1979-01-01

A solid-state radioimmunoassay system has been developed that is useful for automated analysis of samples in microtiter plates. Assays for interspecies and type-specific antigenic determinants of the C-type retrovirus protein, p30, have been used to identify clones of cells producing this protein. This method allows testing of at least 1000 clones a day, making it useful for studies of frequencies of virus protein induction, defective virus production, and formation of recombinant viruses

Continuum modeling investigation of gigahertz oscillators based on a C60 fullerene inside cyclic peptide nanotubes

Science.gov (United States)

Sadeghi, F.; Ansari, R.; Darvizeh, M.

2016-02-01

Research concerning the fabrication of nano-oscillators with operating frequency in the gigahertz (GHz) range has become a focal point in recent years. In this paper, a new type of GHz oscillators is introduced based on a C60 fullerene inside a cyclic peptide nanotube (CPN). To study the dynamic behavior of such nano-oscillators, using the continuum approximation in conjunction with the 6-12 Lennard-Jones (LJ) potential function, analytical expressions are derived to determine the van der Waals (vdW) potential energy and interaction force between the two interacting molecules. Employing Newton's second law, the equation of motion is solved numerically to arrive at the telescopic oscillatory motion of a C60 fullerene inside CPNs. It is shown that the fullerene molecule exhibits different kinds of oscillation inside peptide nanotubes which are sensitive to the system parameters. Furthermore, for the precise evaluation of the oscillation frequency, a novel semi-analytical expression is proposed based on the conservation of the mechanical energy principle. Numerical results are presented to comprehensively study the effects of the number of peptide units and initial conditions (initial separation distance and velocity) on the oscillatory behavior of C60 -CPN oscillators. It is found out that for peptide nanotubes comprised of one unit, the maximum achievable frequency is obtained when the inner core oscillates with respect to its preferred positions located outside the tube, while for other numbers of peptide units, such frequency is obtained when the inner core oscillates with respect to the preferred positions situated in the space between the two first or the two last units. It is further found out that four peptide units are sufficient to obtain the optimal frequency.

Role of C-peptide in Altered Lipid Profile among Apparently Healthy Adults of Vijayapura City, Karnataka

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Chandrahas M.Kulkarni

2016-04-01

Full Text Available Background: C-peptide is produced in equimolar concentration during insulin production as inactive molecule by beta islet cells of Langerhans. C-peptide is most useful biomarker of endogenous insulin production. Aim and Objectives: To predict metabolic syndrome in advance by estimation of C-peptide and lipid profile in healthy adults. Material and Methods: Serum C-peptide, fasting blood glucose and lipid profile of 128 healthy individuals were estimated. Adults in the age group of 18 to 60 years of both sexes were included in study. Results: C-peptide levels were increased in 27%, Serum cholesterol in 30%, LDL Cholesterol in 55% and triglyceride levels in 21% of healthy individuals. Significant correlation was observed between C peptide, age, serum cholesterol, LDL and cholesterol LDL ratio in male subjects only. In our study group most of the subjects (both males and females fell in overweight group. Conclusion: Cpeptide level and lipid profile may be considered as useful biomarkers to predict type 2 diabetes mellitus in advance, possibly due to insulin resistance.

Insulin and C-peptide secretion in non-obese patients with polycystic ovarian disease.

Science.gov (United States)

Mahabeer, S; Jialal, I; Norman, R J; Naidoo, C; Reddi, K; Joubert, S M

1989-09-01

Plasma glucose, immunoreactive insulin (IRI) and C-peptide responses during an oral glucose tolerance test (oGTT) were assessed in 11 non-obese patients with polycystic ovarian disease (PCOD) and 11 reference subjects matched for age, height and weight. Also, 6 patients with PCOD and 6 normal women were subjected to intravenous glucose tolerance testing (ivGTT) On oGTT, all subjects exhibited normal glucose tolerance; however, PCOD patients had significantly higher mean plasma glucose levels at 30, 60, 90 and 120 min and higher mean incremental glucose areas. In addition the patients with polycystic ovaries showed higher mean basal IRI and C-peptide levels, higher mean glucose stimulated IRI and C-peptide levels and higher mean incremental IRI and C-peptide values. The molar ratios of C-peptide/IRI were significantly lower in the PCOD group at all time intervals after glucose stimulation when compared to the normal women. During ivGTT, there were significantly higher mean glucose levels at 5, 40, 50 and 60 min in the PCOD group when compared to the reference group. The IRI response to intravenous glucose in the PCOD women was similar to the reference group. The findings on oGTT suggest that non-obese patients with PCOD have increased pancreatic IRI secretion as well as impaired hepatic extraction of the hormone.

Determination of the minimal fusion peptide of bovine leukemia virus gp30

International Nuclear Information System (INIS)

Lorin, Aurelien; Lins, Laurence; Stroobant, Vincent; Brasseur, Robert; Charloteaux, Benoit

2007-01-01

In this study, we determined the minimal N-terminal fusion peptide of the gp30 of the bovine leukemia virus on the basis of the tilted peptide theory. We first used molecular modelling to predict that the gp30 minimal fusion peptide corresponds to the 15 first residues. Liposome lipid-mixing and leakage assays confirmed that the 15-residue long peptide induces fusion in vitro and that it is the shortest peptide inducing optimal fusion since longer peptides destabilize liposomes to the same extent but not shorter ones. The 15-residue long peptide can thus be considered as the minimal fusion peptide. The effect of mutations reported in the literature was also investigated. Interestingly, mutations related to glycoproteins unable to induce syncytia in cell-cell fusion assays correspond to peptides predicted as non-tilted. The relationship between obliquity and fusogenicity was also confirmed in vitro for one tilted and one non-tilted mutant peptide

A competitive-inhibiton radioimmunoassay for influenza virus envelope antigens

International Nuclear Information System (INIS)

Russ, G.; Styk, B.; Vareckova, E.; Polakova, K.

1976-01-01

A double-antibody competitive-inhibition radioimmunoassay for influenza virus envelope antigens is described. A viral antigen preparation from influenza A virus recombinant MRC11 [antigenically identical to A/Port Chalmers/1/73 (H3N2)] consisting of haemagglutinin and neuraminidase was labelled with radioiodine. Rabbit antisera were allowed to react with the labelled antigen and the resultant antigen-antibody complexes were precipitated with the appropriate antiglobulin. The competitive-inhibition radioimmunoassay very sensitively elucidated differences even among closely related influenza virus strains. Attempts have been made to eliminate neuraminidase from radioimmunoprecipitation to obtain a competitive-inhibition radioimmunoassay system for haemagglutinin alone. (author)

Stereoselective determination of amino acids in beta-amyloid peptides and senile plaques.

Science.gov (United States)

Thorsén, G; Bergquist, J; Westlind-Danielsson, A; Josefsson, B

2001-06-01

A novel method for the determination of the enantiomeric composition of peptides is presented. In this paper, the focus has been on beta-amyloid peptides from deceased Alzheimer's disease patients. The peptides are hydrolyzed using mineral acid. The free amino acids are derivatized with the chiral reagent (+)- or (-)-1-(9-anthryl)-2-propyl chloroformate and subsequently separated using micellar electrokinetic chromatography (MEKC) and detected using laser-induced fluorescence (LIF) detection. The high separation efficiency of the MEKC-LIF system, yielding approximately 1 million theoretical plates/m for most amino acids, facilitates the simultaneous chiral determination of nine amino acids. The samples that have been analyzed were standard 1-40 beta-amyloid peptides, in vitro precipitated beta-amyloid fibrils, and human senile plaque samples.

Radioimmunoassay of vasoactive intestinal polypeptide (VIP) in plasma. [/sup 125/I tracer techniques

Energy Technology Data Exchange (ETDEWEB)

Fahrenkrug, J.; Schaffalitzky de Muckadell, O.B.

1977-06-01

A sensitive and specific radioimmunoassay for vasoactive intestinal polypeptide (VIP) has been developed, which can detect 3.3 pmol x L/sup -1/ of the peptide in plasma. Antisera to highly purified porcine VIP coupled to albumin were raised in eight rabbits. The final dilution, the avidity, and the specificity of each antiserum were determined. /sup 125/I-VIP served as label, and highly purified porcine VIP was used as standard. Separation of antibody-bound and free VIP was achieved by plasma-coated charcoal. Nonspecific interference with the assay system was excluded by extraction of plasm samples with ethanol. The reliability of the assay was investigated by recovery experiments, by serial dilution of plasma samples with high concentration of endogenous VIP, and by immunosorption. The within-and between assay reproducibility at a concentration of 18.3 pmol x L/sup -1/ was 1.6 and 2.3 pmol x L/sup -1/ (1 S.D.), respectively. Median fasting concentration of VIP in plasma from 74 normal subjects was 7.3 pmol x L/sup -1/ (range: 0 to 20.0 pmol x L/sup -1/).

Variables associated with persistence of C-Peptide secretion among patients with Type 1 diabetes mellitus

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Ibrahim Abbood Zaboon

2017-01-01

Full Text Available Background: C-peptide is a reliable method for estimating the beta-cell residual function. The objective of this study to assess the variables associated with persistence of C-peptide secretion among patients with Type 1 diabetes mellitus (T1DM. Patients and Methods: This was a cross-sectional study conducted from October 2015 to September 2016. This study enrolled patients with T1DM with at least 1 year or more duration. Random C-peptide with concomitant plasma glucose at least 144 mg/dl (8 mmol/l was measured and at this cutoff considered as a stimulated value. Variables that were assessed were age at the time of enrollment, age at the diagnosis of diabetes, gender, family history of diabetes, duration of diabetes, frequency of insulin per day, insulin dose (units/kg/day, type of insulin, devices delivery, body mass index (BMI at enrollment, blood pressure, glucose (plasma, lipid profile, glycated hemoglobin (HbA1c, thyrotropin (TSH, and antibodies to glutamic acid decarboxylase (GAD65, thyroid peroxidase antibodies (anti-TPO, and tissue transglutaminase antibodies-IgA (anti-TTG-IgA. Results: A total 324 patients were included in the study. A higher level of C-peptide has been seen if the disease acquired at the age of 18 years and older with detectable C-peptide observed among 17.7% of those diagnosed at age <18 years versus 31.7% for those aged 18 years or above. The more the duration of diabetes, the more is the loss of C-peptide. On logistic regression analysis, only duration of diabetes <6 years, and insulin dose <1 U/kg/day were statistically significantly associated with the detectable level of C-peptide in this cohort of T1DM. Conclusion: Diagnosis of TIDM at a late age, positive family history of diabetes, those requiring <1 U of insulin per kg per day, and higher fasting glucose was associated with higher and more detectable C-peptide. On multivariable analysis, the only duration of diabetes <6 years and insulin dose <1 U of insulin

A simplified radioimmunoassay for digoxin determination using a 125-I-labelled solid-phase kit

International Nuclear Information System (INIS)

Doering, W.; Bluemel, E.

1978-01-01

Our experience with a commercially available kit (Radioimmunoassay DIGOXIN, Boehringer, Mannheim) using ( 125 J)-labelled digoxin and antibody-coated tubes is reported. This simplified method requires only two pipetting steps per sample and results can be obtained in 70 min. The intra- and interassay coefficient of variation ranged between 7% and 8%. The specific digoxin antibody antibody gave no clinical relevant cross-reactions with spironolactone or prednisone ( [de

Radioimmunoassay of bovine heart protein kinase

International Nuclear Information System (INIS)

Fleischer, N.; Rosen, O.M.; Reichlin, M.

1976-01-01

Immunization of guinea pigs with bovine cardiac cAMP-dependent protein kinase (ATP : protein phosphotransferase, EC 2.7.1.37) resulted in the development of precipitating antibodies to the cAMP-binding subunit of the enzyme. Both the phosphorylated and nonphosphorylated cAMP-binding protein of the protein kinase reacted with the antiserum. A radioimmunoassay was developed that detects 10 ng of holoenzyme and permits measurement of enzyme concentrations in bovine cardiac muscle. Bovine liver, kidney, brain, and skeletal muscle contain protein kinases which are immunologically identical to those found in bovine cardiac muscle. However, the proportion of immunoreactive enzyme activity differed for each tissue. All of the immunologically nonreactive enzyme in skeletal muscle and heart was separable from immunoreactive enzyme by chromatography on DEAE-cellulose. Rat tissues and pig heart contained protein kinase activity that cross reacted immunologically in a nonparallel fashion with bovine cardiac enzyme. These results indicate that cAMP-dependent protein kinases within and between species are immunologically heterogeneous

Determination of hormone parathyroid by radioimmunoassay

International Nuclear Information System (INIS)

Fisher-Ferraro, Catalina; Moos de Ephraim, Monica; Mautalen, Carlos; Mitta, A.E.A.

1978-10-01

The labelling of bovine parathyroid hormone and its employment for the determination of seric PTH by radioimmunoanalysis is described. The specific activity of 131 I PTH is 200-350mCi/mg and the damage 3-5%. The method used for radioimmunoanalysis was that of C.D. Arnaud and coworkers. (author) [es

Measurement of endotoxin. I. Fundamental studies on radioimmunoassay of endotoxin

Energy Technology Data Exchange (ETDEWEB)

Kimura, H [Okayama Univ. (Japan). School of Medicine

1976-08-01

A method for estimating endotoxin by radioimmunoassay was recently introduced. The present paper describes improvements in the speed and sensitivity on this endotoxin measurement. Antigen was purified from E. coli 0111: B4(B) lipopolysaccharide by centrifugation and dialysis. Purified anti-endotoxin antibody was prepared from immunized rabbit serum. A radioimmunoassay system was established with the antigen and antibody. Dextran-coated charcoal was used to separate the antibody-bound antigen from free antigen. Experimental studies were also performed on possible factors related to the antigen-antibody reaction. Accurate measurements on quantitites as low as 100 pg/ml (10 ng/ml in the plasma) were performed by the dextran-coated charcoal method, and the reaction time was reduced to 2 hr at 4/sup 0/C. This new method does not require strict sterilization or aseptic handling, and therefore is quite practical for quantitative measurements of endotoxin.

Clinical indications of prolactin radioimmunoassay

International Nuclear Information System (INIS)

Lengyel, A.M.J.; Vieira, J.G.H.; Zanella, M.R.; Zampieri, M.; Chacra, A.R.

1980-01-01

Is a review is presented of the main clinical uses of prolactin measurements, including the galactorrhea-amenorrhea syndrome, an experiment employing the prolactin radioimmunoassay is related. (Author) [pt

A radioimmunoassay for equilin in equine pregnancy plasma

International Nuclear Information System (INIS)

Park, B.K.; Rance, Th.A.; Dean, P.D.G.

1976-01-01

It is well known that the pregnant mare produces large quantities of the ring B unsaturated steroid equilin in addition to classical oestrogens. However, the precise biogenesis of this unusual steroid remains a mystery. To facilitate a study of the interrelationship of the steroids present during equine pregnancy, a radioimmunoassay for the measurement of equilin in peripheral plasma was developed. As equilin is thought to be a product of the foeto-placental unit, such an assay may also be of use as an index of foetal well-being. Oestrone and equilin are present in similar concentrations in equine pregnancy plasma so it was important that an antiserum was produced which could differentiate between these two steroids. An antigen was synthesised in which equilin is linked to a protein carrier through the 17-position in order that the C 7 -C 8 double bond might be fully exposed for immune recognition. This stratagem proved successful as the antiserum obtained gave a cross-reaction of only 7.3% for oestrone. The use of a radioimmunoassay incorporating this antiserum is demonstrated by measuring equilin concentrations in plasma samples taken from a mare at weekly intervals from day 60 of pregnancy through to parturition. The corresponding oestrone concentrations are also recorded and demonstrate the validity of the equilin assay in this situation

C-peptide prevents SMAD3 binding to alpha promoters to inhibit collagen type IV synthesis.

Science.gov (United States)

Li, Yanning; Zhong, Yan; Gong, Wenjian; Gao, Xuehan; Qi, Huanli; Liu, Kun; Qi, Jinsheng

2018-07-01

Activation of transforming growth factor β1 (TGFB1)/SMAD3 signaling may lead to additional synthesis of collagen type IV (COL4), which is a major contributor to extracellular matrix (ECM) accumulation in diabetic nephropathy (DN). C-peptide can attenuate fibrosis to have unique beneficial effects in DN. However, whether and how C-peptide affects TGFB1/SMAD3-activated COL4 synthesis is unclear. In this study, pathological changes, expression of COL4 a1-a5 chains ( Col4a1-a5 ), COL4 distribution and protein and TGFB1 and SMAD3 protein were first assessed in a rat model of diabetes. Then, rat mesangial cells were treated with high glucose (HG) and/or C-peptide to investigate the underlying mechanism. Col4a1-a5 expression, COL4 protein and secretion, TGFB1 protein, SMAD3 nuclear translocation and binding of SMAD3 to its cognate sites in the promoters of Col4a1a2 , Col4a3a4 and Col4a5 were measured. It was found that C-peptide attenuated glomerular pathological changes and suppressed renal Col4a1 -a5 mRNA expression, COL4 protein content and TGFB1 protein content. C-peptide had a dose-dependent effect to inhibit Col4a1-a5 mRNA expression, COL4 protein content and secretion, in HG-stimulated mesangial cells. In addition, the HG-induced increase in TGFB1 protein content was significantly reduced by C-peptide. Although not apparently affecting SMAD3 nuclear translocation, C-peptide prevented SMAD3 from binding to its sites in the Col4a1a2 , Col4a3a4 and Col4a5 promoters in HG-stimulated mesangial cells. In conclusion, C-peptide could prevent SMAD3 from binding to its sites in the Col4a1a2 , Col4a3a4 and Col4a5 promoters, to inhibit COL4 generation. These results may provide a mechanism for the alleviation of fibrosis in DN by C-peptide. © 2018 Society for Endocrinology.

Cloning of cDNAs encoding new peptides of the dermaseptin-family.

Science.gov (United States)

Wechselberger, C

1998-10-14

Dermaseptins are a group of basic (lysine-rich) peptides, 27-34 amino acids in length and involved in the defense of frog skin against microbial invasion. By using a degenerated oligonucleotide primer binding to the 5'-untranslated region of previously characterized cDNAs of these peptides, it was possible to identify new members of the dermaseptin family in the South American frogs Agalychnis annae and Pachymedusa dacnicolor. Amino acid alignment and secondary structure prediction reveals, that only five of the deduced peptides can be supposed to be also functional homologs to the known dermaseptins from Phyllomedusa bicolor and Phyllomedusa sauvagei. The remaining six peptides described in this paper have not been isolated and characterized yet.

Effect of glucagon-like peptide-1 on alpha- and beta-cell function in C-peptide-negative type 1 diabetic patients

DEFF Research Database (Denmark)

Kielgast, Urd; Asmar, Meena; Madsbad, Sten

2010-01-01

The mechanism by which glucagon-like peptide-1 (GLP-1) suppresses glucagon secretion is uncertain, and it is not determined whether endogenous insulin is a necessary factor for this effect.......The mechanism by which glucagon-like peptide-1 (GLP-1) suppresses glucagon secretion is uncertain, and it is not determined whether endogenous insulin is a necessary factor for this effect....

TRH radioimmunoassay for unextracted human urine

International Nuclear Information System (INIS)

Mitsuma, Terunori; Hirooka, Yoshibumi; Nihei, Noriyuki

1975-01-01

The authors developed a TRH radioimmunoassay for unextracted human urine using anti-TRH antibody produced by immunization of rabbits with a TRH-bis-diazotized-bovine serum albumin conjugate. The antibody had no crossreactivity with TRH analogues, amino acids or pituitary hormones, but with L or DL-Aze3-TRH. TRH was radioiodinized by Greenwood-Hunter's method, followed by purification on Sephadex G-10. Inactivation of TRH by serum was well documented. The authors found however that this inactivation of TRH could be prevented by adjusting the pH to 3.0 or by keeping the temperature between 4 0 C and -20 0 C. All assay procedures were performed in 0.01 M phosphate buffer with 0.15 M NaCl (pH 7.5) at 4 0 C. Free and bound forms were separated with a second antibody system. In this system, sensitivity was 0.01 ng/tube, recovery was approximately 100%, intrassay reproducibility was 3.2% and interassay variation was 9.8%. TRH levels in urine measured with this system were undetectable to 9.0 ng/ml in normal subjects, undetectable in hyperthyroid patients or a tertiary hypothyroid patient and 13 to 24 ng/ml in primary hypothyroid patients. Approximately 6 percent of the intravenously administered TRH was excreted into the urine within 12 hours following administration in a normal subject. As a result this assay system is quite attractive for clinical determination as well as research application. (Evans, J.)

A novel bioassay for the activity determination of therapeutic human brain natriuretic peptide (BNP.

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Lei Yu

Full Text Available BACKGROUND: Recombinant human brain natriuretic peptide (rhBNP is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A. METHODOLOGY/PRINCIPAL FINDINGS: An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA. Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision. CONCLUSION/SIGNIFICANCE: The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis.

C-Peptide Is Independently Associated with an Increased Risk of Coronary Artery Disease in T2DM Subjects: A Cross-Sectional Study.

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Lingshu Wang

Full Text Available C-peptide has been reported to be a marker of subclinical atherosclerosis in type 2 diabetes mellitus (T2DM patients, whereas its role in coronary artery disease (CAD has not been clarified, especially in diabetics with differing body mass indices (BMIs.This cross-sectional study included 501 patients with T2DM. First, all subjects were divided into the following two groups: CAD and non-CAD. Then, binary logistic regression was used to determine the risk factors for CAD for all patients. To clarify the role of obesity, we re-divided all subjects into two additional groups (obese and non-obese based on BMI. Finally, binary logistic regression was used to determine the risk factors for CAD for each weight group.The patients with CAD showed a higher BMI and fasting C-peptide level in addition to an increased prevalence of traditional risk factors for CAD, such as hypertension, insulin resistance, higher cholesterol, cysteine-C (Cys-C and lower estimated glomerular filtration rate (eGFR. Logistic regression analysis showed that fasting C-peptide (OR=1.513, p=0.005, insulin treatment (OR=1.832, p=0.027 hypertension (OR=1.987, p=0.016 and hyperlipidemia (OR=4.159, p<0.001 significantly increased the risk of clinical CAD in the T2DM patients independent of age, gender, diabetes duration, smoking and alcohol statuses, fasting insulin and glucose, hypoglycemic episodes, UA and eGFR. Additionally, in both of the obese (OR=1.488, p=0.049 and non-obese (OR=1.686, p=0.037 DM groups, C-peptide was associated with an increased risk of CAD after multiple adjustments.C-peptide is associated with an increased CAD risk in T2DM patients, no matter whether they are obese or not.

Radioimmunoassay of prostaglandin F in plasma of pregnant women

International Nuclear Information System (INIS)

Albert, P.

1980-01-01

The aim of this dissertation was to determine quantitatively prostaglandin-F in the plasma of pregnant women in order to obtain further knowledge on changes in PG-F during pregnancy, in particular during the last three months. The plasma of women with clinically normal pregnancies was taken. Prior to radioimmunoassay the plasma was extracted (separation of PG from other plasma components) and chromatography carried out (group separation of PG). The efficiency of this process, as measured by the recovery rate of 3 H-PGF, lies between 60.99% and 93.01% for extraction and between 80.58% and 92.16% for chromatography. The plasma was extracted and analysed chromatographically for the assay. The radioimmunoassay was carried out according to the procedure recommended by the manufacturer. A calibration curve was produced without difficulty. The results of the examination of plasma samples were unsatisfactory because of the low sensitivity of the assay; PG-F values of the same order were obtained for all weeks of pregnancy. (orig./MG) [de

The radioimmunoassay of clomipramine (Anafranil-Geigy): a tricyclic antidepressant

International Nuclear Information System (INIS)

Read, G.F.; Riad-Fahmy, D.

1977-01-01

A radioimmunoassay has been developed for the tricyclic antidepressant, clomipramine (Anafranil-Geigy) which allows accurate determination of plasma levels without a pr-assay purification step. This is achieved by generation of specific antisera using an antigen produced by conjugation of clomipramine to bovine serum albumin via the 10,11 bridge positions. As expected cross reaction of the pharmacologically active major metabolite, desmethylclomipramine was 5% and that of didesmethyclomipramine 1%. Specificity was confirmed by comparing titres achieved in the routine assay with those observed in an assay incorporating a pre-assay thin layer chromatographic purification step. Pharmacokinetic data were in agreement with double radioisotope derivative assays and also with previously reported assays using G.C. or G.C./M.S. techniques. The sensitivity is superior to any previous assay known to us for this class of compound. The specificity and precision, coupled with the high sample turnover (greater than 300 samples/week per technician) make the assay ideal for supervision of patient compliance and routine assay of samples generated in large clinical trials. (orig.) [de

Non-equilibrium method for the radioimmunoassay of clozapine in the presence of metabolites

International Nuclear Information System (INIS)

Rosenthaler, J.; Nimmerfall, F.; Sigrist, R.; Munzer, H.

1977-01-01

Cross-reactions with metabolites are an ever-recurring problem encountered in the use of radioimmunoassay techniques to determine active compounds in biological material. Metabolites may interfere with the assay of the parent drug to a variable extent. Taking 8-chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo[b,e][1,4]diazepine (clozapine) as an example, it was shown that the extent to which the antiserum produced interacts with the parent drug and the metabolites can be estimated by determining the equilibrium constants and the kinetics. In the present case, therefore, it was advantageous to carry out the radioimmunoassay in disequilibrium, i.e. in order to differentiate the metabolites from the parent drug, the sample was incubated with the antiserum for 10 min, after which the labelled antigen was added and the reaction mixture again incubated for a brief, exactly timed interval. It was shown that cross-reactions did not occur in mixtures of clozapine and its N-demethyl and N-oxide metabolites in the proportions 1 : 1 : 2 over a range of concentration of 1.5-48 ng clozapine per 100 μl human plasma. The equilibrium constants measured with the clozapine goat antiserum were as follows: clozapine 1.2 x 10 8 M -1 , the N-demethyl metabolite 4.6 x 10 7 M -1 and the N-oxide 3.7 x 10 7 M -1 (pH 7.5 and 20 0 C). (orig.) [de

Radioimmunoassay of serum myoglobin in neuromuscular diseases

Energy Technology Data Exchange (ETDEWEB)

Askmark, H; Osterman, P O; Roxin, L E; Venge, P [University Hospital, Uppsala (Sweden)

1981-01-01

Radioimmunoassay of serum myoglobin was performed in 85 patients with muscular symptoms. Elevated levels were found in 93% of patients with myogenic myopathy, in 54% with myasthenia gravis and in 50% with neurogenic myopathy. All 11 patients with polymyositis had elevated myoglobin concentrations. In six of seven patients with polymyositis, who were followed up with repeated determinations, a clear relationship between myoglobin levels and clinical course was found. In general serum myoglobin seemed to be a more sensitive indicator of muscle disease than creatine kinase.

Radioimmunoassay of serum myoglobin in neuromuscular diseases

International Nuclear Information System (INIS)

Askmark, H.; Osterman, P.O.; Roxin, L.-E.; Venge, P.

1981-01-01

Radioimmunoassay of serum myoglobin was performed in 85 patients with muscular symptoms. Elevated levels were found in 93% of patients with myogenic myopathy, in 54% with myasthenia gravis and in 50% with neurogenic myopathy. All 11 patients with polymyositis had elevated myoglobin concentrations. In six of seven patients with polymyositis, who were followed up with repeated determinations, a clear relationship between myoglobin levels and clinical course was found. In general serum myoglobin seemed to be a more sensitive indicator of muscle disease than creatine kinase. (author)

Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

International Nuclear Information System (INIS)

Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C.; Jong, Marion de

2010-01-01

In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of 111 In-albumin, 111 In-minigastrin, 111 In-exendin and 111 In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of 111 In-albumin, 111 In-exendin and 111 In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of 111 In-minigastrin, by 88%. Uptake of 111 In-exendin and 111 In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

Radioimmunoassay of luteinizing hormone in hypothyroidism

International Nuclear Information System (INIS)

Sobieszczyk, S.

1975-01-01

Radioimmunoassay of luteinizing hormone was performed in 18 women with primary hypothyroidism and 15 women with secondary hypothyroidism. The results of determinations were compared with LH values found in healthy women at reproductive age and after menopause. It was observed that in primary hypothyroidism the level of LH is normal, in young women it was from 6 to 25 m IU/ml, while in the postmenopausal period it increased to 70 to 200 m IU/ml. In secondary hypothyroidism due to pituitary hypofunction the LH level is undetectable or lies in the range of lowest values observed in healthy subjects, not exceeding 8 m IU/ml. Determinations of serum LH may be useful for differential diagnosis of primary and secondary hypothyroidism. (author)

Development of SAAP3D force field and the application to replica-exchange Monte Carlo simulation for chignolin and C-peptide.

Science.gov (United States)

Iwaoka, Michio; Suzuki, Toshiki; Shoji, Yuya; Dedachi, Kenichi; Shimosato, Taku; Minezaki, Toshiya; Hojo, Hironobu; Onuki, Hiroyuki; Hirota, Hiroshi

2017-12-01

Single amino acid potential (SAAP) would be a prominent factor to determine peptide conformations. To prove this hypothesis, we previously developed SAAP force field for molecular simulation of polypeptides. In this study, the force field was renovated to SAAP3D force field by applying more accurate three-dimensional main-chain parameters, instead of the original two-dimensional ones, for the amino acids having a long side-chain. To demonstrate effectiveness of the SAAP3D force field, replica-exchange Monte Carlo (REMC) simulation was performed for two benchmark short peptides, chignolin (H-GYDPETGTWG-OH) and C-peptide (CHO-AETAAAKFLRAHA-NH 2 ). For chignolin, REMC/SAAP3D simulation correctly produced native β-turn structures, whose minimal all-atom root-mean-square deviation value measured from the native NMR structure (except for H) was 1.2 Å, at 300 K in implicit water, along with misfolded β-hairpin structures with unpacked aromatic side chains of Tyr2 and Trp9. Similar results were obtained for chignolin analog [G1Y,G10Y], which folded more tightly to the native β-turn structure than chignolin did. For C-peptide, on the other hand, the α-helix content was larger than the β content on average, suggesting a significant helix-forming propensity. When the imidazole side chain of His12 was protonated (i.e., [His12Hip]), the α content became larger. These observations as well as the representative structures obtained by clustering analysis were in reasonable agreement not only with the structures of C-peptide that were determined in this study by NMR in 30% CD 3 CD in H 2 O at 298 K but also with the experimental and theoretical behaviors having been reported for protonated C-peptide. Thus, accuracy of the SAAP force field was improved by applying three-dimensional main-chain parameters, supporting prominent importance of SAAP for peptide conformations.

Development of SAAP3D force field and the application to replica-exchange Monte Carlo simulation for chignolin and C-peptide

Science.gov (United States)

Iwaoka, Michio; Suzuki, Toshiki; Shoji, Yuya; Dedachi, Kenichi; Shimosato, Taku; Minezaki, Toshiya; Hojo, Hironobu; Onuki, Hiroyuki; Hirota, Hiroshi

2017-12-01

Single amino acid potential (SAAP) would be a prominent factor to determine peptide conformations. To prove this hypothesis, we previously developed SAAP force field for molecular simulation of polypeptides. In this study, the force field was renovated to SAAP3D force field by applying more accurate three-dimensional main-chain parameters, instead of the original two-dimensional ones, for the amino acids having a long side-chain. To demonstrate effectiveness of the SAAP3D force field, replica-exchange Monte Carlo (REMC) simulation was performed for two benchmark short peptides, chignolin (H-GYDPETGTWG-OH) and C-peptide (CHO-AETAAAKFLRAHA-NH2). For chignolin, REMC/SAAP3D simulation correctly produced native β-turn structures, whose minimal all-atom root-mean-square deviation value measured from the native NMR structure (except for H) was 1.2 Å, at 300 K in implicit water, along with misfolded β-hairpin structures with unpacked aromatic side chains of Tyr2 and Trp9. Similar results were obtained for chignolin analog [G1Y,G10Y], which folded more tightly to the native β-turn structure than chignolin did. For C-peptide, on the other hand, the α-helix content was larger than the β content on average, suggesting a significant helix-forming propensity. When the imidazole side chain of His12 was protonated (i.e., [His12Hip]), the α content became larger. These observations as well as the representative structures obtained by clustering analysis were in reasonable agreement not only with the structures of C-peptide that were determined in this study by NMR in 30% CD3CD in H2O at 298 K but also with the experimental and theoretical behaviors having been reported for protonated C-peptide. Thus, accuracy of the SAAP force field was improved by applying three-dimensional main-chain parameters, supporting prominent importance of SAAP for peptide conformations.

Radioimmunoassay of total IgE and allergen-specific IgE antibodies with a uniform indicator system in allergies of childhood

International Nuclear Information System (INIS)

Struy, H.; Schuster, R.; Sollich, V.; Thal, W.; Morenz, J.

1984-01-01

Solid-phase radioimmunoassays for the determination of allergen-specific and total IgE have been developed. In an indirect solid-phase radioimmunoassay for the measurement of allergen-specific antibodies PVC blisters coated with allergens and in a sandwich solid-phase radioimmunoassay blisters coated with antihuman IgE antibodies are incubated sequentially with patient serum, unlabelled antihuman IgE from rabbits purified by affinity chromatography, and finally with antirabbitglobulin from sheep. Antirabbitglobuline was purified by immunoadsorption. The 125 I-labelled antibody with a specific activity of 30 kBq/μg antibody protein could be used universally for the determination of antibodies of each immunoglobulin class. In 160 patients mostly with seasonal asthma these assays supported RAST and PRIST kits and were helpful in the diagnosis of atopic diseases. (author)

Radioimmunoassay for metabolites of 9,3''-diacetylmidecamycin, a macrolide antibiotic

International Nuclear Information System (INIS)

Shimada, N.; Ueda, T.; Yokoshima, T.; Umemura, K.; Shomura, T.

1982-01-01

A radioimmunoassay system has been developed for the measurement of two major metabolites of 9,3''-diacetylmidecamycin, Mb-6 and Mb-12. A radioimmunoassay for Mb-6 was performed by using anti-Mb-6 serum and a [ 125 I]tyramined Mb-6 derivative as a radiolabeled antigen. The labeled antigen was prepared by the chloramine T method. The antiserum was obtained from a rabbit immunized with Mb-6 conjugated to bovine serum albumin. The obtained antiserum was cross-reactive with two other metabolites of 9,3''-diacetylmidecamycin, Mb-2 and Mb-12, in addition to Mb-6. This Mb-6 radioimmunoassay system could detect Mb-6 concentrations as low as 100 pg/ml of serum. The coefficients of variation were 4.5% (intra-assay) and 5.1% (inter-assay). A radioimmunoassay for Mb-12, using anti-midecamycin serum and a [ 125 I]tyramined-Mb-12 derivative, has also been developed. The antiserum was cross-reactive only with Mb-12 among the 9,3''-diacetylmidecamycin metabolites. This Mb-12 radioimmunoassay system could detect Mb-12 concentrations as low as 2 ng/ml. The intra- and inter-assay variances were 5.9 and 5.8%, respectively

Trypsin radioimmunoassay

International Nuclear Information System (INIS)

Scheithauer, R.; Wolf, F.; Tympner, F.

1981-01-01

In 29 patients with suspicion of pancreatic disease standard secretin-pancreozymin-test was performed parallel to trypsin determination by radioimmunoassay before and after stimulation with secretin. Mean serum trypsin in normal subjects was 175 ng BIT/ml (range 90-250), the maximum after stimulation being 20 minutes after secreting injection (range 110-550). Preliminary normal values are 270 ng BIT/ml for basal concentration and 650 ng BIT/ml for 20 min after secretin stimulation. In the group of normals there was no case of misinterpretation. In patients with several pathological parameters (n = 10) basal trypsin concentration was increased in 7 cases, the stimulated value was concordant with the definite diagnosis in every case. Significant advantage for diagnostics was derived in patients having had pancreatic diseases before, however being actually normal with respect to standard diagnostic parameters. All these patients revealed increased trypsin concentrations after stimulation and 50% of them showed increased basal values. Equivocal results were seen in patients with endstage pancreatitis as well as in case of obstruction during reduced secretion. (orig.) [de

Sensitive radioimmunoassay for the determination of antibodies to mouse hepatitis virus

Energy Technology Data Exchange (ETDEWEB)

Leibowitz, J L [California Univ., San Diego, La Jolla (USA); Fung, L S; Levy, G A [Toronto Univ., Ontario (Canada)

1983-05-01

A solid-phase radioimmunoassay is described for the detection of antibodies to mouse hepatitis virus. Viruses were purified by velocity and isopycnic gradient centrifugation and 96-well plastic plates were coated with viral antigens. To allow the detection of most serotypes of low titered antisera, a pool of antigens from several viral serotypes were employed. The second antibody, an affinity-purified goat antimouse immunoglobulin, detects IgG, IgM and IgA antibodies. This assay is more sensitive than either the plaque reduction assay or the commercially available enzyme-linked immunosorbant assay and proved to be useful for screening mouse colonies for the presence of mouse hepatitis virus, following seroconversion in experimental animals and in the production of monoclonal antibodies to both structural and nonstructural proteins.

The C-Terminal O-S Acyl Shift Pathway under Acidic Condition to Propose Peptide-Thioesters

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Bo Mi Kim

2016-11-01

Full Text Available Peptide-thioester is a pivotal intermediate for peptide ligation and N-, C-terminal cyclization. In this study, desired pathway and the side products of two C-terminal handles, hydroxyethylthiol (HET and hydroxypropylthiol (HPT are described in different conditions as well as kinetic studies. In addition, a new mechanism of C-terminal residue racemization is proposed on the basis of differentiation of products derived from the two C-terminal handles in preparing peptide thioesters through an acid-catalyzed tandem thiol switch, first by an intramolecular O-S acyl shift, and then by an intermolecular S-S exchange.

Comparison of tritiated and iodinated tracers in the radioimmunoassay of progesterone in cow milk

Energy Technology Data Exchange (ETDEWEB)

Allen, R M; Redshaw, M R [Hoechst Pharmaceuticals Research Ltd., Milton Keynes (UK); Holdsworth, R [Milk Marketing Board, Worcester (UK). Veterinary Research Unit

1980-01-01

Progesterone levels in the milk of cows were determined by two radioimmunoassay methods. Excellent correlation (r = 0.95) was found between the method using an iodinated radioligand and that using a conventional tritiated tracer.

A dietary pattern that is associated with C-peptide and risk of colorectal cancer in women.

Science.gov (United States)

Fung, Teresa T; Hu, Frank B; Schulze, Matthias; Pollak, Michael; Wu, Tianying; Fuchs, Charles S; Giovannucci, Edward

2012-06-01

Higher serum C-peptide concentrations have shown to be associated with an increased risk of colorectal cancer (CRC). Therefore, we used diet information to identify food groups that correlated with fasting serum concentrations of C-peptide and assess the association of this dietary pattern and CRC risk. Major food contributors to fasting C-peptide concentrations were identified with stepwise linear regression in a subsample (n = 833) of women from a large cohort. We then summed the consumption frequency of the major food contributors to form a C-peptide dietary pattern for the entire cohort (n = 66,714). Risk for CRC was computed using Cox proportional hazard model with the C-peptide dietary pattern score as the predictor. In up to 20 years of follow-up, we ascertained 985 cases of CRC and 758 colon cancer. After adjusting for confounders, the C-peptide dietary pattern, characterized by higher meat, fish, and sweetened beverage intake, but lower coffee, high fat dairy, and whole grains intake, showed direct association with CRC risk (RR comparing extreme quintiles = 1.29, 95 % CI = 1.05-1.58, p trend = 0.048). The same comparison was slightly stronger for colon cancer (RR = 1.35, 95 % CI = 1.07-1.70, p trend = 0.009). In stratified analysis, there was no association between the C-peptide dietary pattern and colon cancer among lean and active women. However, for overweight or sedentary women, RR for the same comparison was 1.58 (95 % CI = 1.20-2.07, p trend = 0.002) (p for interaction = 0.007). We derived a dietary pattern that correlated with C-peptide concentrations. This pattern was associated with an increase in colon cancer, especially among women who were overweight or sedentary.

Applications of a solid phase radioimmunoassay (SPRIA) to the micro-determination of ABO blood group

International Nuclear Information System (INIS)

Wu Fenqiang; Guo Jingyuan

1995-01-01

The authors report a simple, rapid, sensitive and accurate solid phase radioimmunoassay (SPRIA) method which has been improved. The research included the tests of its methodological parameters, sensitivity, accuracy, and the studies on its applications to the detection of blood group substances in varied forensic biological materials. The coefficient variation of intra-assay was 5.6%, and that of inter-assay was 10.15%. As to its applications to the forensic serology, the ABO blood groups of human bloodstain, hair follicular tissues and salivary stains had been tested and the results were satisfying. Later, 50 unknown type bloodly samples had been blind tested. The judging level used to identify the positive and negative wells was 800 cpm, that meant, if the radioactive count of a well were over 800 cpm, it was determined as a positive well, if that of a well were below 800 cpm, it was negative well. As SPRIA is a method of micro-determination which can micro-test the blood group antigens contained in varied forensic biological materials, it should has a good future of its applications to the forensic medicine fields

Gastrointestinal peptide levels in obese and anorexic females

International Nuclear Information System (INIS)

Pasley, J.N.; Rice, R.L.; McCullough, S.S.; McKay, D.W.; Rayford, P.L.

1989-01-01

The role of gastrointestinal peptides in eating disorders has yet to be determined. Methods: In this study we examined plasma levels of gastrin (G), cholecystokinin (CCK), and pancreatic polypeptide (PP) in adolescent anorexic, and obese female subjects hospitalized for feeding behavior disorders. Six anorexic, six obese and six control young females (ages 13-26) were studied after an overnight fast and after consuming a liquid test meal. The liquid test meal (Ensure, Ross Laboratories; Columbus OH) consisted of 14% calories as protein, 31.5% calories as fat and 54.5% calories as carbohydrate in a 240ml volume. Plasma levels of gastrointestinal peptides, G, CCK and PP were determined by specific radioimmunoassay. The data were analyzed by one way analysis of variance and the Student's t-test. Results: show that fasting levels of G were greater in control and obese groups than the anorexic subjects. Postprandial G levels for controls were higher than the anorexic, and obese groups respectively. When fasting and postprandial G levels were compared among the same groups only the controls increased after eating. Fasting CCK levels were lower in control and anorexic groups than the obese group. Postprandial CCK levels were higher among control patients compared to anorexic and obese subjects. When fasting and postprandial CCK levels were compared among groups, only control levels increased after eating. Fasting and postprandial PP levels were not different between groups. Postprandial PP levels increased over fasting PP levels only in controls

Identification of novel inhibitors of Pseudomonas aeruginosa MurC enzyme derived from phage-displayed peptide libraries.

Science.gov (United States)

El Zoeiby, Ahmed; Sanschagrin, François; Darveau, André; Brisson, Jean-Robert; Levesque, Roger C

2003-03-01

The machinery of peptidoglycan biosynthesis is an ideal site at which to look for novel antimicrobial targets. Phage display was used to develop novel peptide inhibitors for MurC, an essential enzyme involved in the early steps of biosynthesis of peptidoglycan monomer. We cloned and overexpressed the murA, -B and -C genes from Pseudomonas aeruginosa in the pET expression vector, adding a His-tag to their C termini. The three proteins were overproduced in Escherichia coli and purified to homogeneity in milligram quantities. MurA and -B were combinatorially used to synthesize the MurC substrate UDP-N-acetylmuramate, the identity of which was confirmed by mass spectrometry and nuclear magnetic resonance analysis. Two phage-display libraries were screened against MurC in order to identify peptide ligands to the enzyme. Three rounds of biopanning were carried out, successively increasing elution specificity from round 1 to 3. The third round was accomplished with both non-specific elution and competitive elution with each of the three MurC substrates, UDP-N-acetylmuramic acid (UNAM), ATP and L-alanine. The DNA of 10 phage, selected randomly from each group, was extracted and sequenced, and consensus peptide sequences were elucidated. Peptides were synthesized and tested for inhibition of the MurC-catalysed reaction, and two peptides were shown to be inhibitors of MurC activity with IC(50)s of 1.5 and 0.9 mM, respectively. The powerful selection technique of phage display allowed us to identify two peptide inhibitors of the essential bacterial enzyme MurC. The peptide sequences represent the basis for the synthesis of inhibitory peptidomimetic molecules.

Evaluation of a radioimmunoassay for the determination of anti-native DNA antibodies

International Nuclear Information System (INIS)

Johanet, C.; Soulie, E.; Absalon, Y.B.; Ocwieja, T.; Abuaf, N.

1991-01-01

The anti-native DNA antibodies were measured by a radioimmunoassay (RIA) type Farr assay in the sera from 648 patients: 108 with active or inactive systemic lupus erythematosus (SLE), 181 with clinical symptoms of another connective tissue disease, 171 with liver diseases, 29 with different pathology and 159 normal sera were obtained from a blood bank. The anti-DNA kit has been calibrated against the first international units/ml. This assay has proved to be sensitive and specific, and appears to be reliable for the diagnosis and follow-up of SLE patients. The authors propose a new reference cut-off level higher than producer's one [fr

Basic and clinical study on determination of gastrin in the blood by radioimmunoassay

International Nuclear Information System (INIS)

Yonahara, Yoshio; Kato, Masayuki; Kashima, Hiroshi; Ito, Yasushi; Takahara, Yoshiko

1975-01-01

The usefulness of a radioimmunoassay kit in the determination of gastrin in the blood was examined with the following results. (1) The kit is best used within two weeks during which time its specific radioactivity remains high. Correction of the pH of the buffer solution must be conducted without fail. (2) If the temperature and time of the incubation are strictly controlled, it is possible to obtain almost the same results for each condition of time and temperature. (3) As for reproducibility, scattering was observed to some extent at high concentrations, but little at low concentrations. The recovery rate was as good as 100.6% on the average, indicating the usefulness of this method in clinical tests. (4) In 30 normal subjects, the blood levels of gastrin ranged from 52 to 123 (average 86.8 23.3) pg/ml. In gastric ulcers and duodenal ulcers, it was normal or slightly higher. Further, duodenal ulcers showed higher blood levels than did gastric ulcers, and chronic gastritis showed values slightly higher than normal. It was also interesting that blood levels of gastrin were unusually high in megaloblastic anemias. (author)

A different approach to the radioimmunoassay of thyrotropin releasing hormone

International Nuclear Information System (INIS)

Visser, T.J.; Klootwijk, W.; Docter, R.; Hennemann, G.

1977-01-01

Thyrotropin releasing hormone (TRH) was linked to hemocyanin by means of a dinitrophenylene moiety. TRH (pGlu-His-Pro-NH 2 ) was made to react with a large excess of 1,5-difluoro-2,4-dinitrobenzene to yield Nsup(im)-[5-fluoro-2,4-dinitrophenyl]TRH. After removal of excess reagent the derivative was coupled to hemocyanin with a minimum of side-reactions. From two rabbits out of four immunized with this material valuable antisera were obtained, which were used in the radioimmunoassay of the hypothalamic hormone at a final dilution of 1:7,500 and 1:15,000, respectively. The properties, especially with regard to specificity, of these antisera were studied and compared with another antiserum, which was obtained using a conjugate having TRH linked to thyroglobulin via a p-azophenyl-acetyl moiety. Despite the difference between the derivatives, i.e. the nature and the point of attachment of the side chains, the specificities of the assays were very similar. Deamidation of TRH, deletion of either one of the terminal residues, hydrolysis of the lactam of the pyroglutamyl residue, and replacing Pro-NH 2 by Pro-Gly-NH 2 or by an octapeptide chain yield peptides with strongly diminished cross-reactivities. However, Nsup(im)-benzyl-TRH and pGlu-Phe-Pro-NH 2 were 5-10 times as active as TRH probably due to a closer physico-chemical similarity to the arrangement of the haptens in the conjugates. This suggests that the sensitivity of the radioimmunoassay may be increased markedly by conversion of TRH into the Nsup(im)-dinitrophenyl derivative and by using a related compound for radioiodination. (orig.) [de

Radioimmunoassay of pancreatic glucagon

International Nuclear Information System (INIS)

Nooijen, W.J.

1979-01-01

The author presents some of the problems and concepts related to the development of a radioimmunoassay of pancreatic glucagon. A specific derivatization of glucagon for raising specific anti-glucagon antisera is introduced, and special procedures for diminishing the non-specific effect are outlined. (G.T.H.)

Radioimmunoassay of 17-beta - estradiol in plasma

International Nuclear Information System (INIS)

Kyian, T.S.; Wajchenberg, B.L.

1980-01-01

A radioimmunoassay technique for the measurement of plasma E 2 was standardized utilizing a highly specific antisera against E 2 [-6(-0-carboximetil)-oxime] BSA without the need of previous chromatographic purification. The anti-E 2 serum was highly specificic, showing high affinity with affinity constants:K 1 =1.62 x 10 12 M -1 and K 2 =2.94x10 11 M -1 , calculated by Scatchard plot. The standard-curve sensitivity was 2 picograms. The method was specific and accurate, showing an intra-assay precision with a mean C.V. of 2.9%, with the inter-assay evaluation showing a mean C.V. of 5.0%. This method was employed to evaluate E 2 secretion during the menstrual cycle in 6 normal female. (Author) [pt

Fasting serum C-peptide is useful for initial classification of diabetes mellitus in children and adolescents

Directory of Open Access Journals (Sweden)

Min Jung Cho

2014-06-01

Full Text Available PurposeWith rising obesity rates in children, it is increasingly difficult to differentiate between type 1 and type 2 diabetes mellitus (T1DM, T2DM on clinical grounds alone. Using C-peptide as a method of classifying diabetes mellitus (DM has been suggested. This study aimed to find a correlation between fasting C-peptide level and DM types in children and adolescents.MethodsA total of 223 diabetic children, newly diagnosed at 5 hospitals between January 2001 and December 2012, were enrolled in this study. Initial DM classification was based on clinical and laboratory data including fasting C-peptide at diagnosis; final classification was based on additional data (pancreatic autoantibodies, human leukocyte antigen type, and clinical course.ResultsOf 223 diabetic children, 140 were diagnosed with T1DM (62.8% and the remaining 83 with T2DM (37.2%. The mean serum C-peptide level was significantly lower in children with T1DM (0.80 ng/mL than in children with T2DM (3.91 ng/mL. Among 223 children, 54 had a serum C-peptide level 3.0 ng/mL; 48 of them (97.9% were diagnosed with T2DM.ConclusionIn this study, we found that if the C-peptide level was 3.0 ng/mL, a T1DM diagnosis is unlikely. This finding suggests that serum fasting C-peptide level is useful for classifying DM type at the time of diagnosis in youth.

Comparison of radioimmunoassay and gas chromatographic mass spectrometric assay for d-amphetamine

International Nuclear Information System (INIS)

Powers, K.H.; Ebert, M.H.

1979-01-01

Quantification of low levels of psychotropic drugs (10 -7 to 10 -9 g ml -1 ) in small volumes of plasma requires sensitive and accurate methods. Validation of these methods is best achieved by comparing results obtained using several techniques. In this study, amphetamine levels in plasma were measured using gas chromatography mass spectrometry and radioimmunoassay. Correlation of the results obtained by the two methods was found to be positive and high (R = 0.9822). The average coefficient of variation between assays for gas chromatography mass spectrometry was 5.8% and for radioimmunoassay was 12.3%, while the average coefficient of variation within assays for gas chromatography mass spectrometry was 4.9% and for radioimmunoassay 6.9%. Although gas chromatography mass spectrometry was 1.9 times more sensitive than radioimmunoassay, for most purposes, the convenience of the radioimmunoassay method outweighs the technical superiority of gas chromatography mass spectrometry. (author)

Dwarfism and early death in mice lacking C-type natriuretic peptide

Science.gov (United States)

Chusho, Hideki; Tamura, Naohisa; Ogawa, Yoshihiro; Yasoda, Akihiro; Suda, Michio; Miyazawa, Takashi; Nakamura, Kenji; Nakao, Kazuki; Kurihara, Tatsuya; Komatsu, Yasato; Itoh, Hiroshi; Tanaka, Kiyoshi; Saito, Yoshihiko; Katsuki, Motoya; Nakao, Kazuwa

2001-01-01

Longitudinal bone growth is determined by endochondral ossification that occurs as chondrocytes in the cartilaginous growth plate undergo proliferation, hypertrophy, cell death, and osteoblastic replacement. The natriuretic peptide family consists of three structurally related endogenous ligands, atrial, brain, and C-type natriuretic peptides (ANP, BNP, and CNP), and is thought to be involved in a variety of homeostatic processes. To investigate the physiological significance of CNP in vivo, we generated mice with targeted disruption of CNP (Nppc−/− mice). The Nppc−/− mice show severe dwarfism as a result of impaired endochondral ossification. They are all viable perinatally, but less than half can survive during postnatal development. The skeletal phenotypes are histologically similar to those seen in patients with achondroplasia, the most common genetic form of human dwarfism. Targeted expression of CNP in the growth plate chondrocytes can rescue the skeletal defect of Nppc−/− mice and allow their prolonged survival. This study demonstrates that CNP acts locally as a positive regulator of endochondral ossification in vivo and suggests its pathophysiological and therapeutic implication in some forms of skeletal dysplasia. PMID:11259675

Secretoneurin and PE-11 immunoreactivity in the human dental pulp.

Science.gov (United States)

Steiner, René; Fischer-Colbrie, Reiner; Bletsa, Athanasia; Laimer, Johannes; Troger, Josef

2018-02-01

To explore whether there are differences in the concentration of the secretogranin II-derived peptide secretoneurin and the chromogranin B-derived peptide PE-11 between the healthy and inflamed human dental pulps. Furthermore, colocalization studies with calcitonin gene-related peptide were performed to confirm the sensory origin of the peptidergic nerves in the dental pulp. The concentrations of secretoneurin and PE-11 were determined by highly sensitive radioimmunoassays in extracts of dental pulps, the molecular form of secretoneurin immunoreactivities by RP-HPLC with subsequent radioimmunoassay and colocalization studies with calcitonin gene-related peptide were performed by double immunofluorescence. Only secretoneurin but not PE-11 was detectable by radioimmunoassays whereas nerve fibers could be made visible for both secretoneurin and PE-11. Furthermore, there was a full colocalization of secretoneurin and PE-11 with calcitonin gene-related peptide in immunohistochemical experiments. There were no differences in the concentration of secretoneurin between the healthy and inflamed human dental pulp and moreover, the characterization of the secretoneurin immunoreactivities revealed that only authentic secretoneurin was detected with the secretoneurin antibody. There is unequivocal evidence that secretoneurin and PE-11 are constituents of the sensory innervation of the human dental pulp and although not exclusively but are yet present in unmyelinated C-fibers which transmit predominantly nociceptive impulses. Secretoneurin might be involved in local effector functions as well, particularly in neurogenic inflammation, given that this is the case despite of unaltered levels in inflamed tissue. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elevated C-peptide and insulin predict increased risk of colorectal adenomas in normal mucosa

International Nuclear Information System (INIS)

Vidal, Adriana C; Keku, Temitope O; Lund, Pauline Kay; Hoyo, Cathrine; Galanko, Joseph; Burcal, Lauren; Holston, Rachel; Massa, Berri; Omofoye, Oluwaseun; Sandler, Robert S

2012-01-01

Lower concentrations of the insulin–like growth factor binding protein-1 (IGFBP-1) and elevated concentrations of insulin or C-peptide have been associated with an increase in colorectal cancer risk (CRC). However few studies have evaluated IGFBP-1 and C-peptide in relation to adenomatous polyps, the only known precursor for CRC. Between November 2001 and December 2002, we examined associations between circulating concentrations of insulin, C-peptide, IGFBP-1 and apoptosis among 190 individuals with one or more adenomatous polyps and 488 with no adenomatous polyps using logistic regression models. Individuals with the highest concentrations of C-peptide were more likely to have adenomas (OR = 2.2, 95% CI 1.4-4.0) than those with the lowest concentrations; associations that appeared to be stronger in men (OR = 4.4, 95% CI 1.7-10.9) than women. Individuals with high insulin concentrations also had a higher risk of adenomas (OR = 3.5, 95% CI 1.7-7.4), whereas higher levels of IGFBP-1 were associated with a reduced risk of adenomas in men only (OR = 0.3, 95% CI 0.1-0.7). Overweight and obese individuals with higher C-peptide levels (>1 st Q) were at increased risk for lower apoptosis index (OR = 2.5, 95% CI 0.9-7.1), an association that remained strong in overweight and obese men (OR = 6.3, 95% CI 1.0-36.7). Higher levels of IGFBP-1 in overweight and obese individuals were associated with a reduced risk of low apoptosis (OR = 0.3, 95% CI 0.1-1.0). Associations between these peptides and the apoptosis index in overweight and obese individuals, suggest that the mechanism by which C-peptide could induce adenomas may include its anti-apoptotic properties. This study suggests that hyperinsulinemia and IGF hormones predict adenoma risk, and that outcomes associated with colorectal carcinogenesis maybe modified by gender

The clinical evaluation of combining radionuclide imaging with radioimmunoassay for hashimoto's thyroiditis

International Nuclear Information System (INIS)

Huang Chenggang; Chen Xiaoyan; Deng Yan

2003-01-01

By analysing nuclide image characteristics and radioimmunoassay data of 61 cases with Hashimoto's thyroiditis (HT), HT can be classified five types as below: uneven distribution, diffusion, with hyperfunction, with nodules, nearly normal. The results of radionuclide imaging and the radioimmunoassay of all the types indicate that HT can be preliminarily diagnosed by conscientiously analysing nuclide image characteristics and radioimmunoassay data and linking clinical symptoms and signs

Role of C-type natriuretic peptide in the function of normal human sperm

Directory of Open Access Journals (Sweden)

Hui Xia

2016-01-01

Full Text Available C-type natriuretic peptide (CNP is a newly discovered type of local regulatory factor that mediates its biological effects through the specific, membrane-bound natriuretic peptide receptor-B (NPR-B. Recent studies have established that CNP is closely related to male reproductive function. The aims of this study were to determine the distribution of CNP/NPR-B in human ejaculated spermatozoa through different methods (such as immunolocalization, real time polymerase chain reaction and Western Blot, and then to evaluate the influence of CNP on sperm function i n vitro, such as motility and acrosome reaction. Human semen samples were collected from consenting donors who met the criteria of the World Health Organization for normozoospermia. Our results show that the specific receptor NPR-B of CNP is localized in the acrosomal region of the head and the membrane of the front-end tail of the sperm, and there is no signal of CNP in human sperm. Compared with the control, CNP can induce a significant dose-dependent increase in spermatozoa motility and acrosome reaction. In summary, CNP/NPR-B can affect sperm motility and acrosome reaction, thus regulating the reproductive function of males. CNP may be a new key factor in regulating sperm function.

C-type natriuretic peptide in prostate cancer

DEFF Research Database (Denmark)

Nielsen, Soeren Junge; Iversen, Peter; Rehfeld, Jens F.

2009-01-01

C-type natriuretic peptide (CNP) is expressed in the male reproductive organs in pigs. To examine whether the human prostate also expresses the CNP gene, we measured CNP and N-terminal proCNP in prostate cancer tissue extracts and performed immunohistochemical biopsy staining. Additionally, pro......CNP-derived peptides were quantitated in plasma from patients with prostate cancer. Blood was collected from healthy controls and patients before surgery for localized prostate cancer. Tissue extracts were prepared from tissue biopsies obtained from radical prostatectomy surgery. N-terminal proCNP, proCNP (1......-50) and CNP were measured in plasma and tissue extracts. Biopsies were stained for CNP-22 and N-terminal proCNP. Tissue extracts from human prostate cancer contained mostly N-terminal proCNP [median 5.3 pmol/g tissue (range 1.0-12.9)] and less CNP [0.14 pmol/g tissue (0.01-1.34)]. Immunohistochemistry...

Radioimmunoassay in endocpinology

International Nuclear Information System (INIS)

Ametov, A.S.; Torjtsina, L.K.

1983-01-01

Radioimmunoassay of the level of various hormones in blood for the diagnosis of thyroid gland diseases, diabetes mellitus, pancreatic gland diseases, adrenal cortex, phophorous-calcium exchange, cerebral-hypophysial deseases, peripheric endocrine glands diseases and others are considered. It is shown that CEA methods implantation in clinical practice permits to obtain a number of new data on mechanism of neurohumoral interrelations of various organs and organism systems

Ginkgotides: Proline-Rich Hevein-Like Peptides from Gymnosperm Ginkgo biloba.

Science.gov (United States)

Wong, Ka H; Tan, Wei Liang; Serra, Aida; Xiao, Tianshu; Sze, Siu Kwan; Yang, Daiwen; Tam, James P

2016-01-01

Hevein and hevein-like peptides belong to the family of chitin-binding cysteine-rich peptides. They are classified into three subfamilies, the prototypic 8C- and the 6C- and 10C-hevein-like peptides. Thus far, only five 8C-hevein-like peptides have been characterized from three angiosperms and none from gymnosperm. To determine their occurrence and distribution in the gymnosperm, Ginkgo biloba leaves were examined. Here, we report the discovery and characterization of 11 novel 8C-hevein-like peptides, namely ginkgotides gB1-gB11. Proteomic analysis showed that the ginkgotides contain 41-44 amino acids (aa), a chitin-binding domain and are Pro-rich, a distinguishing feature that differs from other hevein-like peptides. Solution NMR structure determination revealed that gB5 contains a three β-stranded structure shaped by a cystine knot with an additional disulfide bond at the C-terminus. Transcriptomic analysis showed that the ginkgotide precursors contain a three-domain architecture, comprised of a C-terminal tail (20 aa) that is significantly shorter than those of other 8C- and 10C-hevein-like peptides, which generally contain a protein cargo such as a Barwin-like protein (126 aa) or class I chitinase (254 aa). Transcriptomic data mining found an additional 48 ginkgotide homologs in 39 different gymnosperms. Phylogenetic analysis revealed that ginkgotides and their homologs belong to a new class of 8C-hevein-like peptides. Stability studies showed that ginkgotides are highly resistant to thermal, acidic and endopeptidase degradation. Ginkgotides flanked at both the N- and C-terminal ends by Pro were resistant to exopeptidase degradation by carboxypeptidase A and aminopeptidase. Antifungal assays showed that ginkgotides inhibit the hyphal growth of phyto-pathogenic fungi. Taken together, ginkgotides represent the first suite of hevein-like peptides isolated and characterized from gymnosperms. As a group, they represent a novel class of 8C-hevein-like peptides that

21 CFR 862.1135 - C-peptides of proinsulin test system.

Science.gov (United States)

2010-04-01

.... Measurements of C-peptides of proinsulin are used in the diagnosis and treatment of patients with abnormal insulin secretion, including diabetes mellitus. (b) Classification. Class I (general controls). The device...

Radioimmunoassay - renin - angiotensin. Principles of radioimmunoassay and their application in measuring renin and angiotensin

Energy Technology Data Exchange (ETDEWEB)

Krause, D K; Hummerich, W; Poulsen, K [eds.

1978-01-01

Typical pitfalls such as impurity of 'standard', tracer damage, crossreactivity of antiserum, unspecific binding of protecting proteins, blank effects with negative results, charcoal stripping, invisible coprecipitate or uncertainty in the analysis of the calibration curve (graph, logit-log, polynormal or spline function) can occur in any type of radioimmunoassay; they are detailed in the general part of this book. The special position occupied by radioimmunological quantification of parameters of the renin-angiotensin system creates additional, even more serious problems. While the radioimmunological determination of the decapeptide angiotensin I no longer causes major obstacles, measurement of the biologically active octapeptide angiotensin II is still only possible in a few centers. The (indirect) determination of plasma renin is characterized by a situation where the enzyme renin may be clearly defined in theory as a specific 10-11-leucine-leucine-endopeptidase cleaving only a decapeptide, but the actual renin assay, however, measures various forms of renin and other angiotensin-forming (or angiotensin-destroying) enzymes at the same time.

Carcinoembryonic antigen radioimmunoassay in hepatic tumor

International Nuclear Information System (INIS)

Aburano, Tamio; Tonami, Norihisa; Hisada, Kinichi

1976-01-01

Carcinoembryonic antigen (CEA) radioimmunoassay with the sandwich method was performed in addition to both α 1 -fetoprotein (AFP) radioimmunoassay and liver scintigraphy to elevate the diagnostic accuracy of hepatic tumor in nuclear medicine. All of the ten healthy controls and 47 of 52 cases with benign disease showed a CEA titer less than 2.5ng/ml. 78 of 188 cases (41%) of malignant disease showed a titer of over 2.5ng/ml; however most positive cases were metastatic, especially to the liver. In metastatic liver cancer, thirtythree out of 46 cases (72%) showed a strongly positive CEA titer. Over 5ng/ml was taken as the lower limit for predicting metastasis to the liver. On the other hand, in primary liver cancer thirty-two out of 35 cases (91%) showed a strongly positive AFP titer over 200ng/ml, although only one case showed a CEA titer over 5ng/ml. Seven cases (15%) of metastatic liver cancer also showed a strongly positive AFP titer; however six of these positive cases showed a CEA titer over 5ng/ml. In metastatic liver cancer, eleven out of 46 cases (24%) showed no clearcut focal defects on liver scintigram. Nine of these negative cases showed a CEA titer over 5ng/ml, and at subsequent operation metastatic liver lesions were found. The overall diagnostic accuracy for detecting metastatic liver cancer with a combination of both methods was 95%. CEA radioimmunoassay was found to be useful for the elucidation of the nature of focal hepatic lesions in addition to AFP radioimmunoassay, and moreover could be used as an adjunct to liver scintigraphy for the detection of metastatic lesions in the liver. (auth.)

Determination of bovine lactoferrin in dairy products by ultra-high performance liquid chromatography–tandem mass spectrometry based on tryptic signature peptides employing an isotope-labeled winged peptide as internal standard

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jingshun [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Lai, Shiyun [Beingmate Research Institute, Beingmate Baby and Child Food Co., Ltd., Hangzhou 310007 (China); Cai, Zengxuan [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Chen, Qi [Beingmate Research Institute, Beingmate Baby and Child Food Co., Ltd., Hangzhou 310007 (China); Huang, Baifen [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Ren, Yiping, E-mail: renyiping@263.net [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China)

2014-06-01

Highlights: • A UHPLC–MS/MS method for quantification of bovine lactoferrin was developed. • Tryptic fragment LRPVAAEIYGTK was chosen as signature peptide of bovine lactoferrin. • A winged peptide containing isotopically-labeled signature peptide was designed as internal standard. • The method for determining lactoferrin does not discriminate between the different forms of lactoferrin. • Meet the growing demand to quantify bovine lactoferrin in different dairy products. Abstract: A new and sensitive determination method was developed for bovine lactoferrin in dairy products including infant formulas based on the signature peptide by ultra high-performance liquid chromatography and triple-quadrupole tandem mass spectrometry under the multiple reaction monitoring mode. The simple pretreatment procedures included the addition of a winged peptide containing the isotope-labeled signature peptide as internal standard, followed by an enzymatic digestion with trypsin. The signature peptide was chosen and identified from the tryptic hydrolyzates of bovine lactoferrin by ultra high-performance liquid chromatography and quadrupole-time-of-flight tandem mass spectrometry based on sequence database search. Analytes were separated on an ACQUITY UPLC BEH 300 C18 column and monitored by MS/MS in seven minutes. Quantitative result bias due to matrix effect and tryptic efficiency was corrected through the use of synthetic isotope-labeled standards. The limit of detection and limit of quantification were 0.3 mg/100 g and 1.0 mg/100 g, respectively. Bovine lactoferrin within the concentration range of 10–1000 nmol L⁻¹ showed a strong linear relationship with a linear correlation coefficient (r) of >0.998. The intra- and inter-day precision of the method were RSD < 6.5% and RSD < 7.1%, respectively. Excellent repeatability (RSD < 6.4%) substantially supported the application of this method for the determination of bovine lactoferrin in dairy samples. The present method

Determination of bovine lactoferrin in dairy products by ultra-high performance liquid chromatography–tandem mass spectrometry based on tryptic signature peptides employing an isotope-labeled winged peptide as internal standard

International Nuclear Information System (INIS)

Zhang, Jingshun; Lai, Shiyun; Cai, Zengxuan; Chen, Qi; Huang, Baifen; Ren, Yiping

2014-01-01

Highlights: • A UHPLC–MS/MS method for quantification of bovine lactoferrin was developed. • Tryptic fragment LRPVAAEIYGTK was chosen as signature peptide of bovine lactoferrin. • A winged peptide containing isotopically-labeled signature peptide was designed as internal standard. • The method for determining lactoferrin does not discriminate between the different forms of lactoferrin. • Meet the growing demand to quantify bovine lactoferrin in different dairy products. - Abstract: A new and sensitive determination method was developed for bovine lactoferrin in dairy products including infant formulas based on the signature peptide by ultra high-performance liquid chromatography and triple-quadrupole tandem mass spectrometry under the multiple reaction monitoring mode. The simple pretreatment procedures included the addition of a winged peptide containing the isotope-labeled signature peptide as internal standard, followed by an enzymatic digestion with trypsin. The signature peptide was chosen and identified from the tryptic hydrolyzates of bovine lactoferrin by ultra high-performance liquid chromatography and quadrupole-time-of-flight tandem mass spectrometry based on sequence database search. Analytes were separated on an ACQUITY UPLC BEH 300 C18 column and monitored by MS/MS in seven minutes. Quantitative result bias due to matrix effect and tryptic efficiency was corrected through the use of synthetic isotope-labeled standards. The limit of detection and limit of quantification were 0.3 mg/100 g and 1.0 mg/100 g, respectively. Bovine lactoferrin within the concentration range of 10–1000 nmol L −1 showed a strong linear relationship with a linear correlation coefficient (r) of >0.998. The intra- and inter-day precision of the method were RSD < 6.5% and RSD < 7.1%, respectively. Excellent repeatability (RSD < 6.4%) substantially supported the application of this method for the determination of bovine lactoferrin in dairy samples. The present

Radioimmunoassay for the determination of free and conjugated abscisic acid

International Nuclear Information System (INIS)

Weiler, E.W.

1979-01-01

The characterization and application of a radioimmunoassay specific for free and conjugated abscisic acid (ABA) is reported, The antibodies produced against a bovine serum albumin-(+-)-ABA conjugate have a high affinity for ABA (Ka= 1.3 x 10 9 l mol -1 ). Trans, trans-ABA and related compounds, such as xanthoxin, phaseic acid, dihydrophaseic acid, vomifoliol or violaxanthin do not interfere with the assay. The detection limit of this method is 0.25 x 10 -12 mol ABA, the measuring range extends to 20 x 10 -12 mol, and average recoveries are 103%. Because of the high specificity of this immunoassay, no extract purification steps are required prior to analysis. Several hundred plants can be analyzed per day in a semi-automatic assay performance. ABA has been detected in all higher plant families examined, but was absent in the blue-green alga, Spirulina platensis, the liverwort Marchantia polymorpha, and two species of fungi. (orig.) [de

Atrial natriuretic peptide stimulates salt secretion by shark rectal gland by releasing VIP

Energy Technology Data Exchange (ETDEWEB)

Silva, P.; Stoff, J.S.; Solomon, R.J.; Lear, S.; Kniaz, D.; Greger, R.; Epstein, F.H.

1987-01-01

Salt secretion by the isolated perfused rectal gland of the spiny dogfish shark, Squalus acanthias, is stimulated by synthetic rat atrial natriuretic peptide (ANP II) as well as extracts of shark heart, but not by 8-bromo-cyclic guanosine 5'-monophosphate. Cardiac peptides have no effect on isolated rectal gland cells or perfused tubules, suggesting that stimulation requires an intact gland. The stimulation of secretion by ANP II is eliminated by maneuvers that block neurotransmitter release. Cardiac peptides stimulate the release of vasoactive intestinal peptide (VIP), known to be present in rectal glands nerves, into the venous effluent of perfused glands in parallel with their stimulation of salt secretion, but the release of VIP induced by ANP II is prevented by perfusion with procaine. VIP was measured by radioimmunoassay. Cardiac peptides thus appear to regulate rectal gland secretion by releasing VIP from neural stores within the gland. It is possible that other physiological effects of these hormones might be explained by an action to enhanced local release of neurotransmitters.

Atrial natriuretic peptide stimulates salt secretion by shark rectal gland by releasing VIP

International Nuclear Information System (INIS)

Silva, P.; Stoff, J.S.; Solomon, R.J.; Lear, S.; Kniaz, D.; Greger, R.; Epstein, F.H.

1987-01-01

Salt secretion by the isolated perfused rectal gland of the spiny dogfish shark, Squalus acanthias, is stimulated by synthetic rat atrial natriuretic peptide (ANP II) as well as extracts of shark heart, but not by 8-bromo-cyclic guanosine 5'-monophosphate. Cardiac peptides have no effect on isolated rectal gland cells or perfused tubules, suggesting that stimulation requires an intact gland. The stimulation of secretion by ANP II is eliminated by maneuvers that block neurotransmitter release. Cardiac peptides stimulate the release of vasoactive intestinal peptide (VIP), known to be present in rectal glands nerves, into the venous effluent of perfused glands in parallel with their stimulation of salt secretion, but the release of VIP induced by ANP II is prevented by perfusion with procaine. VIP was measured by radioimmunoassay. Cardiac peptides thus appear to regulate rectal gland secretion by releasing VIP from neural stores within the gland. It is possible that other physiological effects of these hormones might be explained by an action to enhanced local release of neurotransmitters

The association between newborn regional body composition and cord blood concentrations of C-peptide and insulin-like growth factor I

DEFF Research Database (Denmark)

Carlsen, Emma M; Renault, Kristina M; Jensen, Rikke B

2015-01-01

BACKGROUND: Third trimester fetal growth is partially regulated by C-peptide and insulin-like growth factor I (IGF-I). Prenatal exposures including maternal obesity and high gestational weight gain as well as high birth weight have been linked to subsequent metabolic disease. We evaluated...... with both C-peptide (p tissue accumulation was associated with cord blood C-peptide and IGF-I. Total and abdominal fat masses were related to C-peptide but not to IGF-I. Thus, newborn adiposity is partially mediated through C-peptide and early...

Radioimmunoassay of anabolic steroids

International Nuclear Information System (INIS)

Hampl, R.; Stranska, I.; Starka, L.; Picha, J.; Chundela, B.

1978-01-01

Alternative antisera against 17 α-methyltestosterone and 19-nortestosterone were raised and used for radioimmunoassay of anabolic steroids. Tritiated compounds were used as radioligands. The RIA method suitable for doping control is proposed for 17 α-alkylated anabolic steroids in both plasma and urine, using qoat antiserum against methyltestosterone-3-carboxymethyloxime-BSA. Sensitivity of the method was expressed as least amount of nonradioactive methandienone which, when added to normal urine or plasma, caused statistically significant decrease of measured supernatant radioactivity at 99% level. The amounts from 50 to 500 pg were tested, each in eight parallel determinations. The amounts of 100 pg for plasma and 200 pg for urine met these criteria. The respective coefficients of variation did not depend on the amount of steroid added in this range. They averaged 4.60% for plasma and 4.95% for urine, respectively. (T.I.)

Steroid radioimmunoassay: contribution of standards to blank values, ch. 4

International Nuclear Information System (INIS)

Froelich, M.; Termorshuizen, W.; Kenter, E.; Molenaar, A.J.

1977-01-01

The sensitivity of the radioimmunoassay of steroids is considerably reduced by high blank values which may be derived in part from co-chromatographed standards. Blank levels approach the detection limit of the radioimmunoassay of aldosterone, testosterone and androstenedione when 10,000 dpm (30-35 pg) labelled steroids are used as reference standard. When 20 μg aldosterone, testosterone, or androstenedione is used as standard, blank levels of up to 12,800 pg were measured in the radioimmunoassay. Application of the standards on a separate strip does not improve the results. From the experiments it appeared that contamination took place by transport by the solvent

Reduced ability of C-type natriuretic peptide (CNP) to activate natriuretic peptide receptor B (NPR-B) causes dwarfism in lbab−/− mice

Science.gov (United States)

Yoder, Andrea R.; Kruse, Andrew C.; Earhart, Cathleen A.; Ohlendorf, Douglas H.; Potter, Lincoln R.

2015-01-01

C-type natriuretic peptide (CNP) stimulates endochondrial ossification by activating the transmembrane guanylyl cyclase, natriuretic peptide receptor-B (NPR-B). Recently, a spontaneous autosomal recessive mutation that causes severe dwarfism in mice was identified. The mutant, called long bone abnormality (lbab), contains a single point mutation that converts an arginine to a glycine in a conserved coding region of the CNP gene, but how this mutation affects CNP activity has not been reported. Here, we determined that thirty to greater than one hundred-fold more CNPlbab was required to activate NPR-B as compared to wild-type CNP in whole cell cGMP elevation and membrane guanylyl cyclase assays. The reduced ability of CNPlbab to activate NPR-B was explained, at least in part, by decreased binding since ten-fold more CNPlbab than wild-type CNP was required to compete with [125I][Tyr0]CNP for receptor binding. Molecular modeling suggested that the conserved arginine is critical for binding to an equally conserved acidic pocket in NPR-B. These results indicate that reduced binding to and activation of NPR-B causes dwarfism in lbab−/− mice. PMID:18554750

Radioimmunoassay apparatus

International Nuclear Information System (INIS)

1981-01-01

Apparatus for performing a quantitative radioimmunoassay comprising: a substantially spherical bead for carrying an antibody and a gripper for gripping said bead, said gripper comprising an integrally formed unit having a single elongate handle portion and a plurality of resilient fingers arranged at the base of the handle so that when said bead is secured within said fingers, said bead may be freely rotated about any diametric axis of the bead. In particular the invention relates to an apparatus for a two site immunoradiometric assay for serum ferritin in human blood samples. (author)

Purification and characterization of insulin and the C-peptide of proinsulin from Przewalski's horse, zebra, rhino, and tapir (Perissodactyla).

Science.gov (United States)

Henry, J S; Lance, V A; Conlon, J M

1993-02-01

Within the order Perissodactyla, the primary structure of insulin has been strongly conserved. Insulin from Przewalski's horse and the mountain zebra (suborder Hippomorpha) is the same as that from the domestic horse and differs from insulin from the white rhinoceros and mountain tapir (suborder Ceratomorpha) by a single substitution (Gly-->Ser) at position 9 in the A-chain. A second molecular form of Przewalski's horse insulin isolated in this study was shown to represent the gamma-ethyl ester of the Glu17 residue of the A-chain. This component was probably formed during the extraction of the pancreas with acidified ethanol. The amino acid sequence of the C-peptide of proinsulin has been less well conserved. Zebra C-peptide comprises 31 amino acid residues and differs from Przewalski's horse and domestic horse C-peptide by one substitution (Gln30-->Pro). Rhino C-peptide was isolated only in a truncated form corresponding to residues (1-23) of intact C-peptide. Its amino acid sequence contains three substitutions compared with the corresponding region of horse C-peptide. It is postulated that the substitution (Pro23-->Thr) renders rhino C-peptide more liable to proteolytic cleavage by a chymotrypsin-like enzyme than horse C-peptide. C-peptide could not be identified in the extract of tapir pancreas, suggesting that proteolytic degradation may have been more extensive than in the rhino. In contrast to the ox and pig (order Artiodactyla), there was no evidence for the expression of more than one proinsulin gene in the species of Perissodactyla examined.

The relationship of radioimmunoassay to bioassay: In vitro studies with synthetic lysine vasopressin in aqueous solution inactivated by heat

International Nuclear Information System (INIS)

Loeve Lemboel, H.

1978-01-01

The relationship of radioimmunoassay to pressor assay and antidiuretic assay was investigated in a simple in vitro system of synthetic lysine vasopressin in aqueous solution inactivated by heating at 100 deg C for 9, 18, 27, 36, 54 and 72 h. An apparent dissociation between radioimmunoassay and bioassay was demonstrated, with biological activity being lost more rapidly than immunological activity. The half-times were 32 h for radioimmunoassay, 23 h for antidiuretic assay and 22 h for pressor assay. However, ion-exchange chromatography showed immunological heterogeneity but biological homogeneity of the lysine vasopressin used, and indicated that the presence of impurities in the vasopressin might to some extent explain the discrepancy between assay results. Synthetic arginine vasopressin and arginine vasopressin of pituitary origin showed a similar immunological heterogeneity by ion-exchange chromatography. (author)

Radioimmunoassay for pantothenic acid in blood and other tissues

International Nuclear Information System (INIS)

Wyse, B.W.; Wittwer, C.; Hansen, R.G.

1979-01-01

We described a radioimmunoassay for pantothenic acid in biological tissues. D-Pantothenic acid was conjugated with bovine serum albumin by use of a bromoacetyl derivative of pantothenic acid, and antibody to this antigen was raised by injecting it into the foot pads of rabbits. For the radioimmunoassay, a 100-fold dilution of the resulting antiserum was incubated with radiolabeled panthothentic acid. The antibodies were precipitated and dissolved, and the radioactivity of the solution was measured in a liquid scintillation counter. Between 5 and 125 ng of pantothenic acid can be detected in 75 μL of tissue extract. Validation included recovery and precision studies, parallelism with tissue extracts, and competitive binding studies. Results of the radioimmunoassay and those of microbiological assay with use of Lactobacillus plantarum correlated well

Natriuretic peptides stimulate the cardiac sodium pump via NPR-C-coupled NOS activation

DEFF Research Database (Denmark)

William, M.; Hamilton, E.J.; Garcia, A.

2008-01-01

Natriuretic peptides (NPs) and their receptors (NPRs) are expressed in the heart, but their effects on myocyte function are poorly understood. Because NPRs are coupled to synthesis of cGMP, an activator of the sarcolemmal Na(+)-K(+) pump, we examined whether atrial natriuretic peptide (ANP) regul...

Structural basis of nonribosomal peptide macrocyclization in fungi.

Science.gov (United States)

Zhang, Jinru; Liu, Nicholas; Cacho, Ralph A; Gong, Zhou; Liu, Zhu; Qin, Wenming; Tang, Chun; Tang, Yi; Zhou, Jiahai

2016-12-01

Nonribosomal peptide synthetases (NRPSs) in fungi biosynthesize important pharmaceutical compounds, including penicillin, cyclosporine and echinocandin. To understand the fungal strategy of forging the macrocyclic peptide linkage, we determined the crystal structures of the terminal condensation-like (C T ) domain and the holo thiolation (T)-C T complex of Penicillium aethiopicum TqaA. The first, to our knowledge, structural depiction of the terminal module in a fungal NRPS provides a molecular blueprint for generating new macrocyclic peptide natural products.

Local production of donkey anti-rabbit's sera for human prolactin radioimmunoassay

International Nuclear Information System (INIS)

Hassan, Ammar Mohamed Elamin

2001-11-01

Pure Rabbit's IgG was used in this study to raise donkey anti rabbit's sera to be used as separating agent in radioimmunoassay. Two healthy donkeys have been immunized. The anti rabbit's sera have been titrated as (i) crude, (ii) purified and dialysed coupled to magnetic particles. Then this antibody was used as separating agent in a radioimmunoassay for measurement of human prolactin (PRL). Coupled Sudanese donkey and rabbit's sera (Sud-DARS) was used as 1/8 titre using chelsea RIA kit for human prolactin while 1/200 of liquid Sud-DARS was found to be the best titre using the Chinese kit. The best condition for estimation of the prolactin were optimized by determining the suitable incubation time and temperature. The assay can be done at room temperature but it should be incubated for 6 hours as recommended by the Chinese kit. Validity tests were done. The regression coefficients were 0.994 and 0.999 for linearity and recovery tests respectively. Measurement of human PRL wa found to be reproducible using Sud-DARS as separating agent since the coefficient of variation (C.V. %) was found to be less than 15% for both within batch and between assays. Comparing Sud D ARS to the Chinese kit, separating agent as reference agent, regression coefficient was found to be 0.977 which indicate that Sud-DARS can be used as separating agent. Prolactin in Sudanese subject was determined using the Chinese kit the Sud-DARS as separating agent. The ranges were 74-398 mIU/L in males and 102-414 mI/L in the preovulatory phase for the females while in the post ovulatory phase it was 114-442 mIU/L. Ovulation was confirmed by measurement of progesterone level 7 days before the next suspected mensuration. (Author)

Radioimmunoassay of steroid hormone

International Nuclear Information System (INIS)

Murakami, Tadashi

1975-01-01

Low acid pepsin treated gamma-globulin was applied to ammonium sulfate salting out method, which was a method to separate bound fraction from free one in radioimmunoassay of steroid hormone, and the effect of the separation and the standard curve were examined. Pepsin treated gamma-globulin was prepared in pH 1.5 to 5.5 and then the pepsin was completely removed. It had an effect to accelerate the precipitation in radioimmunoassay of steroid hormone labelled with 3 H. The effect of pepsin treated gamma-globulin to adhere free steroid hormone and to slat out bound one was compared with that of human gamma-globulin. Pepsin treated gamma-globulin, which was water soluble, could easier reach its optimal concentration, and the separation effect was better than human gamma-globulin. The standard curve of it was steeper, particularly in a small dose, and the reproducibility was also better. It could be applied not only to aldosterone and DOC, but also to the steroid hormones, such as progesterone and DHEA, and it seemed suitable for routine measurement method. (Kanao, N.)

Microfilter paper radioimmunoassay of cortisol and dehydroepiandosterone sulphate in capillary blood

International Nuclear Information System (INIS)

Bodrogi, L.; Feher, T.

1982-01-01

A microfilter paper method is reported for cortisol and dehydroepiandosterone sulphate radioimmunoassay in fingertip capillary blood. The steroid content of dry blood spot on filter paper is determined. The results are compared to those obtained by conventional technique used for venous blood. Control experiments validated the introduction of this simple and rapid method to assess hormone function in clinical chemistry. (author)

Dexamethasone stimulates expression of C-type Natriuretic Peptide in chondrocytes

Directory of Open Access Journals (Sweden)

Beier Frank

2006-11-01

Full Text Available Abstract Background Growth of endochondral bones is regulated through the activity of cartilaginous growth plates. Disruption of the physiological patterns of chondrocyte proliferation and differentiation – such as in endocrine disorders or in many different genetic diseases (e.g. chondrodysplasias – generally results in dwarfism and skeletal defects. For example, glucocorticoid administration in children inhibits endochondral bone growth, but the molecular targets of these hormones in chondrocytes remain largely unknown. In contrast, recent studies have shown that C-type Natriuretic Peptide (CNP is an important anabolic regulator of cartilage growth, and loss-of-function mutations in the human CNP receptor gene cause dwarfism. We asked whether glucocorticoids could exert their activities by interfering with the expression of CNP or its downstream signaling components. Methods Primary mouse chondrocytes in monolayer where incubated with the synthetic glucocorticoid Dexamethasone (DEX for 12 to 72 hours. Cell numbers were determined by counting, and real-time PCR was performed to examine regulation of genes in the CNP signaling pathway by DEX. Results We show that DEX does influence expression of key genes in the CNP pathway. Most importantly, DEX significantly increases RNA expression of the gene encoding CNP itself (Nppc. In addition, DEX stimulates expression of Prkg2 (encoding cGMP-dependent protein kinase II and Npr3 (natriuretic peptide decoy receptor genes. Conversely, DEX was found to down-regulate the expression of the gene encoding its receptor, Nr3c1 (glucocorticoid receptor, as well as the Npr2 gene (encoding the CNP receptor. Conclusion Our data suggest that the growth-suppressive activities of DEX are not due to blockade of CNP signaling. This study reveals a novel, unanticipated relationship between glucocorticoid and CNP signaling and provides the first evidence that CNP expression in chondrocytes is regulated by endocrine

Radioimmunoassay and some properties of human antibodies to hepatitis B core antigen

Energy Technology Data Exchange (ETDEWEB)

Neurath, A R; Szmuness, W; Stevens, C E; Strick, N; Harley, E J [New York Blood Center, N.Y. (USA)

1978-03-01

A solid-phase radioimmunoassay for antibodies to hepatitis B core antigen (anti-HBsub(c)) is described. Polystyrene beads coated with anti-HBsub(c), hepatitis B core antigen prepared from pooled sera of humans infected with hepatitis B virus (HBV) and /sup 125/I-labelled anti-HBsub(c) were used for the test. Distinct patterns of development and changes of anti-HBsub(c) and their immunological properties are all related to variations of other markers specific for HBV infections. Knowledge concerning the detailed features of the immune response to hepatitis B core antigen may provide deeper insight into the pathogenesis of HBV infections.

Comparison of the methods for tissue triiodothyronine T(3) extraction and subsequent radioimmunoassay

International Nuclear Information System (INIS)

Takaishi, M.; Miyachi, Y.; Aoki, M.; Shishiba, Y.; Asahi Life Foundation, Tokyo

1978-01-01

Although there have been various reports on tissue T 3 concentration, the examination of the quality of radioimmunoassay has not been available. In the present study, we tried to determine whether the available methods for T 3 extraction are adequate for the various methods of T 3 radioimmunoassays used. T 3 was extracted from liver by ethanol extraction or by acid butanol extraction (Flock's method) and the extract was applied to radioimmunoassay either by Seralute T 3 column, ANS-double antibody or the ANS-charcoal method. The values of T 3 were compared with those obtained by isotope-equilibration method. The dilution curve of ethanol extract was not parallel with that of the standard in ANS-charcoal or ANS-double antibody technique. When the extract was tested by Seralate method, the dilution curve was parallel to the standard, whereas the T 3 value obtained with this method was two-fold higher than that with the isotope equilibration technique. The analysis of the ethanol extract suggested that the lipid extracted by ethanol interfered with the assay. The acid butanol extract when tested either by the ANS-double antibody or Seralate method, showed parallelism to the standard curve and gave T 3 values almost identical with those by the isotope-equilibration method. When tested by ANS-charcoal method, the dilution curve of the acid butanol extract was not parallel to the standard. Thus, to obtain reliable results, tissue extraction by Flock's method and subsequent T 3 radioimmunoassay by either ANS-double antibody or Seralate T 3 method are recommended. (author)

Ginkgotides: Proline-rich Hevein-like Peptides from Gymnosperm Ginkgo biloba

Directory of Open Access Journals (Sweden)

Ka Ho Wong

2016-11-01

Full Text Available Hevein and hevein-like peptides belong to the family of chitin-binding cysteine-rich peptides. They are classified into three subfamilies, the prototypic 8C- and the 6C- and 10C-hevein-like peptides. Thus far, only five 8C-hevein-like peptides have been characterized from three angiosperms and none from gymnosperm. To determine their occurrence and distribution in the gymnosperm, Ginkgo biloba leaves were examined. Here, we report the discovery and characterization of eleven novel 8C-hevein-like peptides, namely ginkgotides gB1–gB11. Proteomic analysis showed that the ginkgotides contain 41–44 amino acids (aa, a chitin-binding domain and are Pro-rich, a distinguishing feature that differs from other hevein-like peptides. Solution 1H-NMR structure determination revealed that gB5 contains a three β-stranded structure shaped by a cystine knot with an additional disulfide bond at the C-terminus. Transcriptomic analysis showed that the ginkgotide precursors contain a three-domain architecture, comprised of a C-terminal tail (20 aa that is significantly shorter than those of other 8C- and 10C-hevein-like peptides, which generally contain a protein cargo such as a Barwin-like protein (126 aa or class I chitinase (254 aa. Transcriptomic data mining found an additional 48 ginkgotide homologs in 39 different gymnosperms. Phylogenetic analysis revealed that ginkgotides and their homologs belong to a new class of 8C-hevein-like peptides. Stability studies showed that ginkgotides are highly resistant to thermal, acidic and endopeptidase degradation. Ginkgotides flanked at both the N- and C-terminal ends by Pro were resistant to exopeptidase degradation by carboxypeptidase A and aminopeptidase. Antifungal assays showed that ginkgotides inhibit the hyphal growth of phyto-pathogenic fungi. Taken together, ginkgotides represent the first suite of hevein-like peptides isolated and characterized from gymnosperms. As a group, they represent a novel class of 8C

A rapid radioimmunoassay using 125I-labeled staphylococcal protein A for antibody to varicella-zoster virus

International Nuclear Information System (INIS)

Richman, D.D.; Cleveland, P.H.; Oxman, M.N.; Zaia, J.A.

1981-01-01

A sensitive radioimmunoassay for serum antibody to varicella-zoster virus is described; it uses 125I-labeled staphylococcal protein A and a specially designed immunofiltration apparatus. The assay accurately distinguishes between individuals who are susceptible and those who are immune to infection with varicella-zoster virus. In addition, it can detect passive antibody in recipients of varicella-zoster immune globulin. This radioimmunoassay also detects the heterologous antibody responses that occasionally occur in patients infected with herpes simplex virus, which also have been detected by other antibody assays. The particular advantages of this assay are the use of noninfectious reagents, the speed of execution (less than 3 hr), the requirement for only small quantities of serum (30 microliters), the objectivity of end-point determination, and the capability of screening large numbers of sera. Consequently, this radioimmunoassay is especially useful for the rapid identification of susceptible individuals, which is essential for the appropriate management of patients and hospital personnel after exposure to varicella

A sensitive radioimmunoassay for the determination of antibodies to mouse hepatitis virus

International Nuclear Information System (INIS)

Leibowitz, J.L.; Fung, L.S.; Levy, G.A.

1983-01-01

A solid-phase radioimmunoassay is described for the detection of antibodies to mouse hepatitis virus. Viruses were purified by velocity and isopycnic gradient centrifugation and 96-well plastic plates were coated with viral antigens. To allow the detection of most serotypes of low titered antisera, a pool of antigens from several viral serotypes were employed. The second antibody, an affinity-purified goat antimouse immunoglobulin, detects IgG, IgM and IgA antibodies. This assay is more sensitive than either the plaque reduction assay or the commercially available enzyme-linked immunosorbant assay and proved to be useful for screening mouse colonies for the presence of mouse hepatitis virus, following seroconversion in experimental animals and in the production of monoclonal antibodies to both structural and nonstructural proteins. (Auth.)

Development of a double-antibody radioimmunoassay for detecting ovarian tumor-associated antigen fraction OCA in plasma

International Nuclear Information System (INIS)

Knauf, S.; Urbach, G.I.

1978-01-01

Ovarian tumor-associated antigen isolated from human tumor tissue was shown to have a different mobility from that of carcinoembryonic antigen (CEA) in both acrylamide gel electrophoresis and immunoelectrophoresis in agarose. The ovarian tumor antigen is composed of six species with different electrophoretic mobility in acrylamide gel electrophoresis. Three of these species were detected in Sephadex G-100 ovarian fraction OCA (from the void volume peak) and the other three species of lower apparent molecular weight were detected in fraction OCD (from the second peak). Fractions OCA and OCD did not share common antigenic determinants as determined by immunodiffusion. CEA was shown to share antigenic determinants with both OCA and OCD. A double-antibody radioimmunoassay capable of detecting nanogram quantities of plasma OCA was developed. In a preliminary study of ovarian cancer patients, OCA appeared to be a more sensitive marker for ovarian cancer than CEA. There was virtually no correlation (r 2 = 0.1) between OCA and CEA levels in these patients, as determined by radioimmunoassay

Structure of antigenetic determinants in the amino-terminal region of bovine fibrinogen Aα chain

International Nuclear Information System (INIS)

Tanswell, P.; Reiter, H.; Timpl, R.

1978-01-01

A radioimmunoassay was developed for peptide F-CB1α from the amino of bovine fibrinogen Aα chain, isolated after reduction and carboxymethylation of the multichain disulfide-linked cyanogen bromide peptide F-CB1. Seven out of twelve different rabbit antisera produced against fibrinogen, peptide F-CB1 or Aα chain showed distinct binding to 125 I-labelled F-CB1α. Thrombin cleavage of F-CB1α yielded two fragments: fibrinopeptide A (residues 1-19) and the carboxy-terminal fragment Th2 (residues 20-54). Antisera could be classified into three groups according to whether they recognized antigenic determinants on fibrinopeptide A, on peptide Th2 or as they showed diminished reactions with both fragments. Only little or no cross-reaction was observed with the amino-terminal cyanogen bromide peptides of Bβ and γ chain. Proteolytic fragments of fibrinopeptide A were isolated and tested for inhibitory activity with two antisera. One antiserum contained anitbodies binding selectively to the amino-terminal sequence (residues 4-11) and did not cross-react with human fibrinopeptide A. Another antiserum showed a specific binding restricted to the carboxy-terminal sequence (residues 11-18) and cross-reacted completely with human fibrinopeptide A. These results correlate well with the primary structures of the two fibrinopeptides. The antigenic activity of the peptide fragment Th2 was localized on a 15-residue tryptic peptide derived from the central portion of the sequence. These and further data indicate that at least six different antigenic determinants are present in peptide F-CB1α. (orig.) 891 AJ [de

The differences in heparin binding for the C-terminal basic-sequence-rich peptides of HPV-16 and HPV-18 capsid protein L1

International Nuclear Information System (INIS)

Sun Jian; Yu Jisheng; Yu Zhiwu; Zha Xiao; Wu Yuqing

2012-01-01

Graphial abstract: The differences in heparin binding for the C-terminal basic-sequence-rich peptides of HPV-16 and HPV-18 capsid protein L1. Highlights: ► Several driving forces contribute to the interaction between heparin and peptides. ► C-terminal of HPV L1 is a potential candidate for the attachment to host cells. ► The C-terminal peptides of HPV-16 and -18 L1 have different heparin-binding. ► The different heparin-binding provides an explanation for the distinct prevalences. - Abstract: The high-risk types of human papillomaviruses (HPV) HPV-16 and -18 are the predominant types associated with cervical cancer. HPV-16 and -18 account for about 50% and 20%, respectively, of cervical cancers worldwide. While the reason and molecular mechanism of the distinct prevalence and distributions between them remain poorly understood, the binding affinity of cell surface receptor with capsid proteins, especially L1, may be involved. We examined heparin binding with two synthetic peptides corresponding to the 14 amino acid C-terminal peptides of HPV-16 and -18 L1 with the goal of comparing the equivalent residues in different HPV types. Using isothermal titration calorimetry (ITC) and static right-angle light scattering (SLS), we determined the binding constant K, reaction enthalpy ΔH, and other thermodynamic parameters in the interaction. Especially, we assessed the role of specific residues in binding with heparin by comparing the NMR spectra of free and heparin-bound peptides.

The production of antibodies for radioimmunoassay

International Nuclear Information System (INIS)

Court, G.

1975-01-01

Three factors which affect the outcome of any immunisation schedule designed to produce antisera for radio-immunoassay, the antigen, the method of immunisation and the choice of animal are considered. Several factors concerning the nature of the antigen are dealt with, for example, the molecular size and immunogenicity of the antigen. It is noted that the larger polypeptide and proteins are sufficiently immunogenic to elicit a useful antibody response alone and that whilst substances with molecular weights of less than 2000 may produce a response alone they will probably produce a better one if they are conjugated (chemically coupled) to a much larger molecule. The method of immunisation is discussed including a consideration of the use of adjuvant and the route and timing of injections. It is noted that antisera showing the relevant properties for radio-immunoassay are rarely produced without emulsification of the immunogen in Freund's adjuvant although this is not an absolute requirement for antibody production. Data are presented comparing the intramuscular and multiple intradermal routes of injection. The results, however, fail to demonstrate any major advantage for either method although the latter may be more economical, producing high titre antisera with relatively small amounts of immunogen. Because of their convenience rabbits are generally the first choice of animal for raising antisera for radioimmunoassay although guinea pigs, chickens and sheep have been used successfully in many cases

Occurrence of C-Terminal Residue Exclusion in Peptide Fragmentation by ESI and MALDI Tandem Mass Spectrometry

Science.gov (United States)

Dupré, Mathieu; Cantel, Sonia; Martinez, Jean; Enjalbal, Christine

2012-02-01

By screening a data set of 392 synthetic peptides MS/MS spectra, we found that a known C-terminal rearrangement was unexpectedly frequently occurring from monoprotonated molecular ions in both ESI and MALDI tandem mass spectrometry upon low and high energy collision activated dissociations with QqTOF and TOF/TOF mass analyzer configuration, respectively. Any residue localized at the C-terminal carboxylic acid end, even a basic one, was lost, provided that a basic amino acid such arginine and to a lesser extent histidine and lysine was present in the sequence leading to a fragment ion, usually depicted as (bn-1 + H2O) ion, corresponding to a shortened non-scrambled peptide chain. Far from being an epiphenomenon, such a residue exclusion from the peptide chain C-terminal extremity gave a fragment ion that was the base peak of the MS/MS spectrum in certain cases. Within the frame of the mobile proton model, the ionizing proton being sequestered onto the basic amino acid side chain, it is known that the charge directed fragmentation mechanism involved the C-terminal carboxylic acid function forming an anhydride intermediate structure. The same mechanism was also demonstrated from cationized peptides. To confirm such assessment, we have prepared some of the peptides that displayed such C-terminal residue exclusion as a C-terminal backbone amide. As expected in this peptide amide series, the production of truncated chains was completely suppressed. Besides, multiply charged molecular ions of all peptides recorded in ESI mass spectrometry did not undergo such fragmentation validating that any mobile ionizing proton will prevent such a competitive C-terminal backbone rearrangement. Among all well-known nondirect sequence fragment ions issued from non specific loss of neutral molecules (mainly H2O and NH3) and multiple backbone amide ruptures (b-type internal ions), the described C-terminal residue exclusion is highly identifiable giving raise to a single fragment ion in

Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

Science.gov (United States)

Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

2015-01-01

Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

Transdermal delivery of a melanotropic peptide hormone analogue

International Nuclear Information System (INIS)

Dawson, B.V.; Hadley, M.E.; Kreutzfeld, K.; Dorr, R.T.; Hruby, V.J.; Al-Obeidi, F.; Don, S.

1988-01-01

We previously reported that topical application of [Nl3 4 ,D-Phe 7 ]alpha-MSH, a superpotent analogue of alpha-melanocyte stimulating hormone, to mice induces a darkening of follicular melanocytes throughout the skin. We now report that the melanotropin analogue can be delivered across mouse but not rat skin in an in vitro model system. Passage of the analogue from the topically applied vehicle (polyethylene glycol) across the skin into a subcutaneous receiving vessel was demonstrated by both bioassay as well as by radioimmunoassay. The bioassay data demonstrate that percutaneous absorption of the melanotropin did not result in loss of biological activity of the peptide. The differential penetration of the peptide across rodent skin reveals that one cannot predict percutaneous absorption of a substance across the stratum corneum from studies on a single species. The present results are the first to demonstrate, by direct quantitative measurements, that a bioactive peptide can be delivered across the vertebrate integument in vitro. These studies point out the potential of a topically applied melanotropin for tanning of the skin and possibly for treatment of certain hypopigmentary disorders

Oxytocin determination by radioimmunoassay in cattle. 1

International Nuclear Information System (INIS)

Schams, D.; Schmidt-Polex, B.; Kruse, V.

1979-01-01

A radioimmunoassay for oxytocin in cow plasma is described. Antisera were raised in rabbits against synthetic oxytocin coupled to bovine thyroglobulin. Iodinated oxytocin free of unlabelled oxytocin and most likely also free of diiodo-oxytocin was used as radioactive tracer. The tracer showed a high degree of purity, and was stable on storage. It could be used in the assay for 2-3 months. The assay showed very little cross-reactivity with vasopressin. Acetone was used for the extraction of oxytocin from plasma as well as from standards made of synthetic exytocin in pooled cow plasma. Inhibition curves obtained with plasma collected from cows at parturition were parallel to those obtained with the oxytocin standard preparation. The mean recovery of oxytocin added to cow plasma was 106% (SD=14). The within-assay coefficient of variation (CV) varied from 5.2 to 10.9%, and the between-assay CV was in the order of 13%. The assay sensitivity was 1 pg (0.5 μU) per tube, corresponding to 3 pg/ml plasma. Around the time of milking the plasma oxytocin profile showed a strong response to the preparation for milking, and a further effect related to the attachment of the teat cups of the milking machine. Peak concentrations were in the range of 15-50 pg/ml. During parturition there was a peak of oxytocin (65 pg/ml) coinciding with the expulsion phase. After this peak levels decreased by remained measurably elevated until the expulsion of the placenta. The plasma disappearance curve for immunoreactive oxutocin after the infusion of 100 IU oxytocin over a period of 1 h showed two components with apparent half-lives of 7-9 and 25 min, respectively. (author)

Radioimmunoassay and evaluation for serum SIgA and CG of the hepatopathy patients

International Nuclear Information System (INIS)

Liu Junchi; Du Shujun; Lu Jun; Tang Xiaolin; Mao Shaorong

1995-01-01

Serum SIgA and CG of 247 hepatopathy (male 140, female 99) are radioimmunoassayed. The Clinical Significance of SIgA, CG for hepatisms is evaluated. The results show that the assay of SIgA, CG has an important significance for the doctor to choose the treatment plans and determine the prognosis

Immunodiagnosis of opportunistic mycoses: detection of fungal antigenemia by radioimmunoassays in systemic candidiasis and aspergillosis

International Nuclear Information System (INIS)

Weiner, M.H.

1980-01-01

The authors have developed radioimmunoassays to the Candida carbohydrate, mannan, and to an Aspergillus cell wall carbohydrate. They evaluate these radioimmunoassays with sera from rabbit models of disseminated mycoses, and further evaluate the radioimmunoassays for their diagnostic usefulness in a panel of patient sera. (Auth.)

Development of an enzyme-radioimmunoassay for the measurement of dopamine in human plasma and urine

International Nuclear Information System (INIS)

Faraj, B.A.; Walker, W.R.; Camp, V.M.; Ali, F.M.; Cobbs, W.B. Jr.

1978-01-01

An enzyme-radioimmunoassay for the measurement of dopamine is described. It is based on the incubation of plasma or urine in the presence of catechol-0-methyltransferase and S-adenosylmethionine. The 0-methylated dopamine metabolite formed (3-0-methyldopamine) was characterized by radioimmunoassay. As little as 0.5 ng of dopamine can be detected. The assay was found to be specific, since no cross-reactivity was noted for several compounds related to dopamine. The enzyme-radioimmunoassay of dopamine was used to determine the concentrations of dopamine in urine and plasma of normal volunteers. In this group, urinary dopamine averaged 182.1 +- 2.2 μg/24 hr, and the plasma concentration 0.211 +- 0.052 ng/ml. However, in children wPth neuroblastoma, there was a several-fold increase over controls in the average urinary and plasma levels of dopamine (8,500 μ/24 hr and 2.3 ng/ml). The assay was also used to monitor blood levels of dopamine following the administration of L-dopa and dopamine to patients with cardiomyopathy

The effect of oral and intravenous dextrose on C-peptide secretion in ponies.

Science.gov (United States)

de Laat, M A; van Haeften, J J; Sillence, M N

2016-02-01

Managing equine hyperinsulinemia is crucial for preventing laminitis, but our understanding of the mechanisms involved in insulin dysregulation in this species is incomplete. C-peptide is co-secreted with insulin but is resistant to hepatic metabolism and can be used to study insulin dysregulation. This study examined C-peptide secretion in serial blood samples collected after oral and i.v. dextrose (0.75 g/kg) administration to 9 ponies (BCS, 7.1 ± 0.5). The ponies were designated as hyperinsulinemic (HI) or normoinsulinemic (NI) responders before the study, using oral glucose tests and fasted glucose-to-insulin ratios, and responses were compared between the 2 groups. C-peptide concentrations increased ( dextrose, with similar area under the concentration-time curve (AUC) for both tests and a significant correlation with AUC. The AUC was similar in HI and NI ponies after i.v. dextrose, indicating similar pancreatic capacity for both groups. However, for oral dextrose, the AUC and the AUC were markedly higher ( < 0.05) in the HI ponies, indicating a greater secretion rate of these peptides. Slower insulin clearance might have also contributed to the larger AUC in HI ponies, but this hypothesis requires further investigation with specific measures of hepatic insulin clearance.

A cGMP kinase mutant with increased sensitivity to the protein kinase inhibitor peptide PKI(5-24).

Science.gov (United States)

Ruth, P; Kamm, S; Nau, U; Pfeifer, A; Hofmann, F

1996-01-01

Synthetic peptides corresponding to the active domain of the heat-stable inhibitor protein PKI are very potent inhibitors of cAMP-dependent protein kinase, but are extremely weak inhibitors of cGMP-dependent protein kinase. In this study, we tried to confer PKI sensitivity to cGMP kinase by site-directed mutagenesis. The molecular requirements for high affinity inhibition by PKI were deduced from the crystal structure of the cAMP kinase/PKI complex. A prominent site of interaction are residues Tyr235 and Phe239 in the catalytic subunit, which from a sandwich-like structure with Phe10 of the PKI(5-24) peptide. To increase the sensitivity for PKI, the cGMP kinase codons at the corresponding sites, Ser555 and Ser559, were changed to Tyr and Phe. The mutant cGMP kinase was stimulated half maximally by cGMP at 3-fold higher concentrations (240 nM) than the wild type (77 nM). Wild type and mutant cGMP kinase did not differ significantly in their Km and Vmax for three different substrate peptides. The PKI(5-24) peptide inhibited phosphotransferase activity of the mutant cGMP kinase with higher potency than that of wild type, with Ki values of 42 +/- .3 microM and 160 +/- .7 microM, respectively. The increased affinity of the mutant cGMP kinase was specific for the PKI(5-24) peptide. Mutation of the essential Phe10 in the PKI(5-24) sequence to an Ala yielded a peptide that inhibited mutant and wild type cGMP kinase with similar potency, with Ki values of 160 +/- 11 and 169 +/- 27 microM, respectively. These results suggest that the mutations Ser555Tyr and Ser559Phe are required, but not sufficient, for high affinity inhibition of cGMP kinase by PKI.

Postprandial C-Peptide to Glucose Ratio as a Marker of β Cell Function: Implication for the Management of Type 2 Diabetes

Directory of Open Access Journals (Sweden)

Yoshifumi Saisho

2016-05-01

Full Text Available C-peptide is secreted from pancreatic β cells at an equimolar ratio to insulin. Since, in contrast to insulin, C-peptide is not extracted by the liver and other organs, C-peptide reflects endogenous insulin secretion more accurately than insulin. C-peptide is therefore used as a marker of β cell function. C-peptide has been mainly used to assess the presence of an insulin-dependent state for the diagnosis of type 1 diabetes. However, recent studies have revealed that β cell dysfunction is also a core deficit of type 2 diabetes, and residual β cell function is a key factor in achieving optimal glycemic control in patients with type 2 diabetes. This review summarizes the role of C-peptide, especially the postprandial C-peptide to glucose ratio which likely better reflects maximum β cell secretory capacity compared with the fasting ratio in assessing β cell function, and discusses perspectives on its clinical utility for managing glycemic control in patients with type 2 diabetes.

Radioimmunoassay of diagoxin with the aid of the solid phase - microtitre plating technique

International Nuclear Information System (INIS)

Scheidt, C.

1982-01-01

Preliminary results are reported here on the development of a digoxin-radioimmunoassay with an anti-digoxin antibody (goat) in a solid phase technique (mictrotitre plate). The advantages compared to conventional RIAs are: Cross reactions towards digoxin is minimal, both in vitro and in vivo. The calibraton range extends from 0.25 to 8 ng/ml. The radioactive load could be reduced significantly by use of smaller amounts of tracer (0.004 μCi/single determination) and by reduction of waste volume (solid), waste weight (solid) and liquid waste. The DIGOXIN RIA BIOTEST MTP is, in addition, the only digoxin radioimmunoassay where radioactive waste is produced in a sealed form. The test is a simple one and can be carried out without the need for complicated apparatus and techniques. (orig./MG) [de

Estimation of antibodies to human cytomegalovirus by immunofluorescence and radioimmunoassay

International Nuclear Information System (INIS)

Jankowski, M.; Gut, W.; Nawrocka, E.

1980-01-01

The 125 I labelled IgG fraction against rabbit IgG of goat origin was employed for the detection of CMV IgG and IgM antibodies in the double indirect radioimmunoassay. The results were compared with those obtained in complement fixation, indirect immunofluorescence and anti-complement immunofluorescence tests. The application of labelled anti-fc antisera, instead of antisera against whole IgG in the tests for detection of specific CMV IgG antibody resulted in increased sensitivity of radioimmunoassay and reduction of non-specific cytoplasmatic reactions in preparations stained by indirect immunofluorescence. The absorption of sera with protein A rich staphylococci and aggregates to immunoglobulin eliminated unwanted secondary IgM staining caused by rheumatoid factors both in indirect immunofluorescence and radioimmunoassay tests for CMV antibodies. (author)

Immunoradiometric assay for prolactin in serum and tissue; Comparison with radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Ohnami, Shumpei; Nakata, Hajime; Eto, Sumiya (University of Occupational and Environmental Health Hospital, Kitakyushu, Fukuoka (Japan))

1990-09-01

Prolactin (PRL) concentrations in sera and tumors of patients with various pituitary tumors were measured by both immunoradiometric assay (IRMA) and radioimmunoassay (RIA). PRL concentrations in sera and tumor tissues measured by IRMA were well correlated with those measured by RIA. PRL concentrations in sera reflected those of tumors removed. This IRMA is a simple and useful method for PRL determination in serum and tissue. (author).

Radioimmunoassay for urinary albumin

International Nuclear Information System (INIS)

Woo, J.; Floyd, M.; Cannon, D.C.; Kahan, B.

1978-01-01

We describe a rapid, sensitive, and precise radioimmunoassay for urinary albumin (U/sub alb/). Aliquots of diluted urine were incubated at room temperature for 1 h with 125 I-labelled albumin and a rabbit antiserum monospecifid for human albumin. Phase separation was effected by the double-antibody technique. The dose-response curve was linear in the range of 15.6 to 10,000 ng, equivalent to 4 to 3000 mg/liter of urine. The limit of sensitivity was 16 ng of albumin. The coefficient of assay variation was 4.8%, both at 44 mg/liter and at 1304 mg/liter. A displacement curve obtained with a serially diluted urine sample of high albumin concentration was completely superimposable with the curve for which human albumin was used as a standard. In 26 normal individuals the range for U/sub alb/ was 2.2 to 12.6 mg/24 h, and for albumin clearance (C/sub alb/), 1.8 x 10 -5 --19.6 x 10 -5 ml/min. After renal homografts in 25 patients, U/sub alb/ ranged from 16.9 to 9928 mg/24 h, and C/sub alb/ from 2.7 x 10 -4 to 1.7 x 10 -1 ml/min. Both increased U/sub alb/ and C/sub alb/ correlated well with the severity of renal homograft rejection

Peptide release, side-chain deprotection, work-up, and isolation

DEFF Research Database (Denmark)

Pedersen, Søren Ljungberg; Jensen, Knud Jørgen

2013-01-01

After having successfully synthesized a peptide, it has to be released from the solid support, unless it is being used for on-resin display. The linker and, in some cases, the cleavage mixture determine the C-terminal functionality of the released peptide. In most cases, the peptide is released w...

Radioimmunoassay of alpha-foeto-protein in hepatology. Observation of 151 cases

International Nuclear Information System (INIS)

Dao, Mouhamadou.

1976-03-01

Alpha-foeto-protein, although discovered several years ago, was considered as only able to exist in primary adult liver cancer. With progress in science and in research it was observed that AFP can be found in normal subjects, without any pathological significance. APF has been found moreover in illnesses other than primary liver cancer. This range of diseases, restricted at first, has continued to widen, a development due to the discovery of new AFP detection methods and radioimmunoassay. Our work, covering 151 cases discussed in detail in the 'Material and Methods' chapter, is interesting from two viewpoints: in hepatology it is useful to know whether the very sensitive radio-immunological method reveals abnormal AFP content variations in different liver diseases; given the large number of hepatomas in our series it is also interesting to have the value of this determination confirmed in primary liver cancer diagnosis. Radioimmunoassay now replaces other quantitative methods (MANCINI's radial immunodiffusion and LAURELL's elec. diffusion) and is the most accurate [fr

Heterologous radioimmunoassay for arginine vasopressin

International Nuclear Information System (INIS)

Shimamoto, K.; Murase, T.; Yamaji, T.

1976-01-01

A sensitive and specific radioimmunoassay for arginine vasopressin (AVP) was developed utilizing the antisera against lysine vasopressin (LVP) in combination with a labeled AVP. The assay employs an acetone extraction procedure and detects as little as 0.8 pg. per millimeter of AVP in human plasma. In normal subjects, the mean (+- S.D.) plasma concentration of AVP was 4.9 +- 1.2 pg. per milliliter after fluid deprivation and 1.2 +- 0.4 pg. per milliliter after water loading. Plasma AVP levels correlated significantly with plasma osmolalities. In four patients with diabetes insipidus, plasma AVP concentrations ranged from less than 0.8 to 1.2 pg. per milliliter, whereas six patients with the syndrome of inappropriate ADH secretion showed plasma levels of AVP which correspond to those of the dehydrated state in normal subjects or greater, although plasma osmolalities were low in all cases. It was concluded that the present radioimmunoassay method for AVP provides a useful way of assessing neurohypophyseal function in man

Does bombesin-like peptide mediate radiation-induced anorexia and satiety?

Energy Technology Data Exchange (ETDEWEB)

Aalto, Y.; Franzen, L.; Henriksson, R. [Umeaa Univ. (Sweden). Dept. of Oncology; Forsgren, S.; Kjoerell, U. [Umeaa Univ. (Sweden). Dept. of Anatomy; Funegaard, U. [Umeaa Univ. (Sweden). Dept. of Cardiology

1999-07-01

Bombesin (BN) and its mammalian counterpart gastrin-releasing peptide (GRP) act as neuroregulatory hormones and peripheral and central satiety-inducing agents. Previously, we demonstrated that irradiation induces an increase in the expression of BN/GRP in the innervation of the salivary glands in rats. We therefore carried out a study using radioimmunoassay (RIA) analysis and immunohistochemistry to examine whether saliva contains BN and whether irradiation affects the BN release to saliva in rats. Immunoreactivity for BN was detected not only in the innervation of the parenchyma but also in the duct cells and in the lumina of the ducts, suggesting entrance of BN into saliva. The RIA analysis confirmed that rat saliva contains a BN-like peptide. The observation shows that saliva contains this peptide but that there is no significant increase following the radiation schedule used. Nevertheless, the occurrence of an enhanced expression of BN in different peripheral tissues such as the salivary and laryngeal glands should be taken into consideration when discussing the clinically important problem of reduced food intake and anorexia in cancer patients. (orig.)

Does bombesin-like peptide mediate radiation-induced anorexia and satiety?

International Nuclear Information System (INIS)

Aalto, Y.; Franzen, L.; Henriksson, R.; Forsgren, S.; Kjoerell, U.; Funegaard, U.

1999-01-01

Bombesin (BN) and its mammalian counterpart gastrin-releasing peptide (GRP) act as neuroregulatory hormones and peripheral and central satiety-inducing agents. Previously, we demonstrated that irradiation induces an increase in the expression of BN/GRP in the innervation of the salivary glands in rats. We therefore carried out a study using radioimmunoassay (RIA) analysis and immunohistochemistry to examine whether saliva contains BN and whether irradiation affects the BN release to saliva in rats. Immunoreactivity for BN was detected not only in the innervation of the parenchyma but also in the duct cells and in the lumina of the ducts, suggesting entrance of BN into saliva. The RIA analysis confirmed that rat saliva contains a BN-like peptide. The observation shows that saliva contains this peptide but that there is no significant increase following the radiation schedule used. Nevertheless, the occurrence of an enhanced expression of BN in different peripheral tissues such as the salivary and laryngeal glands should be taken into consideration when discussing the clinically important problem of reduced food intake and anorexia in cancer patients. (orig.)

Islet Cell Associated Autoantibodies and C-Peptide Levels in Patients with Diabetes and Symptoms of Gastroparesis

Directory of Open Access Journals (Sweden)

Elias S. Siraj

2018-02-01

Full Text Available IntroductionIndividuals with diabetes are at increased risk for complications, including gastroparesis. Type 1 diabetes mellitus (T1DM is an autoimmune disorder resulting in decreased beta-cell function. Glutamic acid decarboxylase-65 antibody (GADA is the most commonly used test to assess autoimmunity while C-peptide level is used to assess beta-cell function. Patients with type 2 diabetes mellitus (T2DM, who are GADA positive, are labeled latent autoimmune diabetes in adults (LADA.ObjectiveTo characterize patients with T1 and T2DM who have symptoms of gastroparesis using GADA and C-peptide levels and to look for association with the presence of gastroparesis and its symptom severity.Design113 T1DM and 90 T2DM patients with symptoms suggestive of gastroparesis were studied. Symptom severity was assessed using Gastroparesis Cardinal Symptom Index (GCSI. Serum samples were analyzed for GADA and C-peptide.ResultsDelayed gastric emptying was present in 91 (81% of T1DM and 60 (67% of T2DM patients (p = 0.04. GADA was present in 13% of T2DM subjects [10% in delayed gastric emptying and 20% in normal gastric emptying (p = 0.2]. Gastric retention and GCSI scores were mostly similar in GADA positive and negative T2DM patients. GADA was present in 45% of T1DM subjects [46% in delayed gastric emptying and 41% in normal gastric emptying (p = 0.81]. Low C-peptide levels were seen in 79% T1DM patients and 8% T2DM. All seven T2DM patients with low C-peptide were taking insulin compared to 52% of T2DM with normal C-peptide.ConclusionGADA was present in 13% while low C-peptide was seen in 8% of our T2DM patients with symptoms of gastroparesis. Neither did correlate with degree of delayed gastric emptying or symptom severity.ClinicalTrials.gov IdentifierNCT01696747.

A Novel Apolipoprotein C-II Mimetic Peptide That Activates Lipoprotein Lipase and Decreases Serum Triglycerides in Apolipoprotein E–Knockout Mice

Science.gov (United States)

Sakurai, Toshihiro; Sakurai-Ikuta, Akiko; Sviridov, Denis; Freeman, Lita; Ahsan, Lusana; Remaley, Alan T.

2015-01-01

Apolipoprotein A-I (apoA-I) mimetic peptides are currently being developed as possible new agents for the treatment of cardiovascular disease based on their ability to promote cholesterol efflux and their other beneficial antiatherogenic properties. Many of these peptides, however, have been reported to cause transient hypertriglyceridemia due to inhibition of lipolysis by lipoprotein lipase (LPL). We describe a novel bihelical amphipathic peptide (C-II-a) that contains an amphipathic helix (18A) for binding to lipoproteins and stimulating cholesterol efflux as well as a motif based on the last helix of apolipoprotein C-II (apoC-II) that activates lipolysis by LPL. The C-II-a peptide promoted cholesterol efflux from ATP-binding cassette transporter ABCA1-transfected BHK cells similar to apoA-I mimetic peptides. Furthermore, it was shown in vitro to be comparable to the full-length apoC-II protein in activating lipolysis by LPL. When added to serum from a patient with apoC-II deficiency, it restored normal levels of LPL-induced lipolysis and also enhanced lipolysis in serum from patients with type IV and V hypertriglyceridemia. Intravenous injection of C-II-a (30 mg/kg) in apolipoprotein E–knockout mice resulted in a significant reduction of plasma cholesterol and triglycerides of 38 ± 6% and 85 ± 7%, respectively, at 4 hours. When coinjected with the 5A peptide (60 mg/kg), the C-II-a (30 mg/kg) peptide was found to completely block the hypertriglyceridemic effect of the 5A peptide in C57Bl/6 mice. In summary, C-II-a is a novel peptide based on apoC-II, which promotes cholesterol efflux and lipolysis and may therefore be useful for the treatment of apoC-II deficiency and other forms of hypertriglyceridemia. PMID:25395590

A sensitive radioimmunoassay for a component of mouse casein

International Nuclear Information System (INIS)

Enami, Jumpei; Nandi, S.; California Univ. Berkeley

1977-01-01

Mouse casein (m.w. 22,000 daltons) has been purified by employing Sephadex G-100 and DEAE-cellulose column chromatographies. A sensitive radioimmunoassay method has been developed by using [ 125 I]-labelled casein and antiserum elicited in rabbits after injection of glutaraldehyde-treated casein. The assay method is capable of detecting as little as 0.1 ng of casein. The use of the present radioimmunoassay method in detecting casein production in cultured mouse mammary explants has also been demonstrated

Localization of receptors for bombesin-like peptides in the rat brain

International Nuclear Information System (INIS)

Moody, T.W.; Getz, R.; O'Donohue, T.L.; Rosenstein, J.M.

1988-01-01

BN-like peptides and receptors are present in discrete areas of the mammalian brain. By radioimmunoassay, endogenous BN/GRP, neuromedin B, and ranatensin-like peptides are present in the rat brain. High-to-moderate concentrations of BN/GRP are present in the rat hypothalamus and thalamus, whereas moderate-to-high densities of neuromedin B and ranatensin-like peptides are present in the olfactory bulb and hippocampus, as well as in the hypothalamus and thalamus. While the distribution of neuromedin B and ranatensin-like peptides appears similar, it is distinct from that of BN/GRP. When released from CNS neurons, these peptides may interact with receptors for BN-like peptides. BN, GRP, ranatensin, and neuromedin B inhibit specific [ 125 I-Tyr4]BN binding with high affinity. By use of in vitro autoradiographic techniques to detect binding of [ 125 I-Tyr4]BN to receptors for BN-like peptides, high grain densities were found in the olfactory bulb and tubercle, the nucleus accumbens, the suprachiasmatic and paraventricular nucleus of the hypothalamus, the central medial and paraventricular thalamic nuclei, the hippocampus, the dentate gyrus, and the amygdala of the rat brain. Some of these receptors may be biologically active and mediate the biological effects of BN-like peptides. For example, when BN is directly injected into the nucleus accumbens, pronounced grooming results and the effects caused by BN are reversed by spantide and [D-Phe12]BN. Thus, the putative BN receptor antagonists may serve as useful agents to investigate the biological significance of BN-like peptides in the CNS

Radioimmunoassay method for triiodothyronine and thyroxine

International Nuclear Information System (INIS)

Hollander, C.S.

1975-01-01

This invention relates to a radioimmunoassay method for triiodothyronine or thyroxine or triiodothyronine and thyroxine present in unextracted serum containing thyroxine binding prealbumin and thyroxine binding globulin. Procedures using 125 I and 131 I are described

C-Peptide Decline in Type 1 Diabetes Has Two Phases: An Initial Exponential Fall and a Subsequent Stable Phase.

Science.gov (United States)

Shields, Beverley M; McDonald, Timothy J; Oram, Richard; Hill, Anita; Hudson, Michelle; Leete, Pia; Pearson, Ewan R; Richardson, Sarah J; Morgan, Noel G; Hattersley, Andrew T

2018-06-07

The decline in C-peptide in the 5 years after diagnosis of type 1 diabetes has been well studied, but little is known about the longer-term trajectory. We aimed to examine the association between log-transformed C-peptide levels and the duration of diabetes up to 40 years after diagnosis. We assessed the pattern of association between urinary C-peptide/creatinine ratio (UCPCR) and duration of diabetes in cross-sectional data from 1,549 individuals with type 1 diabetes using nonlinear regression approaches. Findings were replicated in longitudinal follow-up data for both UCPCR ( n = 161 individuals, 326 observations) and plasma C-peptide ( n = 93 individuals, 473 observations). We identified two clear phases of C-peptide decline: an initial exponential fall over 7 years (47% decrease/year [95% CI -51%, -43%]) followed by a stable period thereafter (+0.07%/year [-1.3, +1.5]). The two phases had similar durations and slopes in patients above and below the median age at diagnosis (10.8 years), although levels were lower in the younger patients irrespective of duration. Patterns were consistent in both longitudinal UCPCR ( n = 162; ≤7 years duration: -48%/year [-55%, -38%]; >7 years duration -0.1% [-4.1%, +3.9%]) and plasma C-peptide ( n = 93; >7 years duration only: -2.6% [-6.7%, +1.5%]). These data support two clear phases of C-peptide decline: an initial exponential fall over a 7-year period, followed by a prolonged stabilization where C-peptide levels no longer decline. Understanding the pathophysiological and immunological differences between these two phases will give crucial insights into understanding β-cell survival. © 2018 by the American Diabetes Association.

Assessment of plasminogen synthesis in vitro by mouse tumor cells using a competition radioimmunoassay for mouse plasminogen

International Nuclear Information System (INIS)

Roblin, R.O.; Bell, T.E.; Young, P.L.

1978-01-01

A sensitive, specific competition radioimmunoassay for mouse plasmin(ogen) has been developed in order to determine whether mouse tumor cells can synthesize plasminogen in vitro. The rabbit anti-BALB/c mouse plasminogen antibodies used in the assay react with the plasminogen present in serum from BALB/c, C3H, AKR and C57BL/6 mice, and also recognized mouse plasmin. The competition radiommunoassay can detect as little as 50 ng of mouse plasminogen. No competition was observed with preparations of fetal calf, human and rabbit plasminogens. A variety of virus-transformed and mouse tumor cell lines were all found to contain less than 100 ng mouse plasminogen/mg of cell extract protein. Thus, if the plasminogen activator/plasmin system is important in the growth or movement of this group of tumor cells, the cells will be dependent upon the circulatory system of the host for their plasminogen supply. (Auth.)

A double antibody radioimmunoassay specific for placental alkaline phosphatase

International Nuclear Information System (INIS)

Dass, S.; Bagshawe, K.D.

1984-01-01

Placental alkaline phosphatase (PLAP) is normally found in enzymically measurable amounts in second and third trimester pregnancy serum. Its occurrence in sera and tumours from patients with malignant disease has led to the development of methods to specifically identify and quantitate the enzyme. Recently immunological techniques have been used, employing antibodies raised to purified PLAP; these include solid phase radioimmunoassays and enzyme-immunoassay. The development of a sensitive, specific, automated double-antibody radioimmunoassay for the measurement of PLAP in serum is reported. (Auth.)

Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

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Ming, Wei, E-mail: weiming@xiyi.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Department of Pharmacology, Xi’an Medical University, Xi’an 710021 (China); Lu, Gan, E-mail: leonming99@163.com [Department of Gynecology of Shaanxi Provincial People’s Hospital, Xi’an, 710068 (China); Xin, Sha, E-mail: 248967979@qq.com [Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an 710032 (China); Huanyu, Lu, E-mail: 2366927258@qq.com [Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi’an 710032 (China); Yinghao, Jiang, E-mail: jiangyh@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Xiaoying, Lei, E-mail: leixiaoy@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Chengming, Xu, E-mail: chengmingxu@yeah.net [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Banjun, Ruan, E-mail: running@163.com [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Li, Wang, E-mail: wanglifw@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); and others

2016-08-05

Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

International Nuclear Information System (INIS)

Ming, Wei; Lu, Gan; Xin, Sha; Huanyu, Lu; Yinghao, Jiang; Xiaoying, Lei; Chengming, Xu; Banjun, Ruan; Li, Wang

2016-01-01

Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

C9/12 Ribbon-Like Structures in Hybrid Peptides Alternating α- and Thiazole-Based γ-Amino Acids.

Science.gov (United States)

Bonnel, Clément; Legrand, Baptiste; Simon, Matthieu; Martinez, Jean; Bantignies, Jean-Louis; Kang, Young Kee; Wenger, Emmanuel; Hoh, Francois; Masurier, Nicolas; Maillard, Ludovic T

2017-12-11

According to their restricted conformational freedom, heterocyclic γ-amino acids are usually considered to be related to Z-vinylogous γ-amino acids. In this context, oligomers alternating α-amino acids and thiazole-based γ-amino acids (ATCs) were expected to fold into a canonical 12-helical shape as described for α/γ-hybrid peptides composed of cis-α/β-unsaturated γ-amino acids. However, through a combination of X-ray crystallography, NMR spectroscopy, FTIR experiments, and DFT calculations, it was determined that the folding behavior of ATC-containing hybrid peptides is much more complex. The homochiral α/(S)-ATC sequences were unable to adopt a stable conformation, whereas the heterochiral α/(R)-ATC peptides displayed novel ribbon structures stabilized by unusual C 9/12 -bifurcated hydrogen bonds. These ribbon structures could be considered as a succession of pre-organized γ/α dipeptides and may provide the basis for designing original α-helix mimics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Serum gonadotropins levels in childhood. Critical comparison between immunoradiometric assays and radioimmunoassays

Energy Technology Data Exchange (ETDEWEB)

Hertogh, R. De; Vankrieken, L. (Physiology of Human Reproduction Research Unit, University of Louvain, School of Medicine, Brussels (Belgium)); Wolter, R.; Vliet, G. Van (Hopital Universitaire des Enfants, Reine Fabiola, Free University of Brussels (Belgium))

1989-01-01

The complex changes in serum LH and FSH levels from infancy to adulthood are diversely evaluated by radioimmunoassays or bioassays. The relative lack of sensitivity and specificity of radioimmunoassay, using polyclonal antibodies, could possibly be overcome by new immunoradiometric assays, using specific antibodies to LH and FSH. Significant differences were indeed observed between radioimmunoassays and immunoradiometric assays. During the prepubertal period, LH levels, measured by the immunoradiometric assays, were below the sensitivity of the method in the majority of the samples. LH levels were, however, well detectable when measured with radioimmunoassay, showing the heterogeneity of circulating LH structures. At the onset of puberty, LH levels increased at least 3 to 4 times in both sexes, when measured with immunoradiometric assays, whereas their increase was only 20 to 60% with the radioimmunoassays. FSH levels remained well detectable in the prepubertal period whether measured by immunoradiometric or radioimmunoassays. At pubertal onset, FSH increase in both sexes was more important in the immunoradiometric assays. The results obtained with immunoradiometric assays give a better insight into the quantitative and qualitative function of the gonadotropes during childhood. The almost complete absence of LH during the prepubertal period and the steep increase at the onset of puberty better reflects the reported data obtained with bioassays. The persistance of significant levels of FSH in the prepubertal ages, and the lesser increase at the onset of puberty, when compared with LH, illustrates that the individual regulation of LH and FSH secretion vary over time and is influenced by developmental factors. (author).

Radioimmunoassay for thyroid stimulating hormone (TSH)

International Nuclear Information System (INIS)

1980-01-01

An improved double antibody radioimmunoassay method is described for the determination of thyroid stimulating hormone (TSH) in biological and other fluids. Highly purified second antibody is immobilised on to hydrophilic, hydrolyzed polyacrylamide particles of a suspendable size to form a solid phase second antibody reagent. The immobilised second antibody reagent is used to precipitate the reaction product of the first antibody with labelled and unlabelled thyroid stimulating hormone (TSH-anti-TSH-complex) so as to produce a two-phase system which permits rapid and efficient separation of bound TSH in the solid phase from free TSH in the liquid phase. Details of the preparation of this novel second antibody-polyacrylamide reagent and of the assay procedure for human TSH are described. (U.K.)

Significance of production of peptide leukotrienes in murine traumatic shock

International Nuclear Information System (INIS)

Craft, D.V.; Lefer, D.J.; Hock, C.E.; Lefer, A.M.

1986-01-01

The authors studied the formation of a leukotriene metabolite in plasma and bile during traumatic shock. Anesthetized rats subjected to Noble-Collip drum trauma developed a lethal shock state characterized by a survival time of 1.9 +/- 0.3h, a 4.5-fold increase in plasma cathepsin D activity, and a reduction in mean arterial blood pressure to 45 +/- 2 mmHg compared with 108 +/- 5 mmHg in sham-shock controls. Plasma and bile samples were analyzed by reverse-phase high-pressure liquid chromatography (HPLC) for peptide leukotrienes, and their retention times were confirmed by co-elution with radioactive standards, radioimmunoassay (RIA), and UV spectrophotometry. No leukotrienes or metabolites were found in plasma. The major peptide leukotriene from bile was eluted between LTC 4 and LTD 4 and corresponds to a metabolite of LTE 4 , N-acetyl-LTE 4 , which is also produced during endotoxin shock. The metabolite increased nearly sevenfold in traumatic shock compared with sham trauma. The identity of the metabolite was confirmed by UV scan, which revealed a spectrum consistent with a peptide leukotriene and similar to that of previously reported spectra for N-acetyl-LTE 4 . In conclusion, peptide leukotrienes are rapidly cleared from the blood and appear in the bile as N-acetyl-LTE 4 , a metabolite of the peptide leukotrienes. These findings support a role of the peptide leukotrienes in the pathogenesis of traumatic shock

Clinical Significance of Determination of the Serum Levels of NT-proBNP and hs-CRP in Patients with Acute Coronary Syndrome

International Nuclear Information System (INIS)

Zheng Zhaojun; Zheng Jing; Sun Weili; Yuan Yuan; Tao Jian; Li Weipeng

2010-01-01

To explore the clinical significance the serum levels of N-Terminal proB-Type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hs-CRP) in patients with acute coronary syndrome,the serum levels of NT-proBNP and hs-CRP in patients and normal controls were determined by ECi Immunity Analyzer and radioimmunoassay respectively. The results showed that the serum levels of NT-proBNP and hs-CRP in patients with acute coronary syndrome were significantly higher than that of controls (P<0.05). The diagnostic specificity for acute coronary syndrome was 100% by combined detection of NT-proBNP and hs-CRP. The results suggest that the combined detection of serum NT-proBNP and hs-CRP levels are very important to evaluate heart function in patients with acute coronary syndrome. (authors)

1 α-hydroxycholecalciferol-25-hydroxy esters and their use in radioimmunoassay

International Nuclear Information System (INIS)

Fairney, A.; Baggiolini, E.; Uskokovic, M.R.

1981-01-01

The invention relates to the determination of 1 α, 25-dihydroxycholecalciferol and of optical enantiomers and racemates thereof. More particularly, the invention is concerned with a radioimmunoassay and a reagent for the determination of 1 α, 25-dihydroxycholecalciferol and of optical enantiomers and racemates thereof, with novel antigens and antibodies useful in the said process and with a process for the preparation of the said antigens and antibodies. The invention is also concerned with novel haptens useful in the preparation of said antigens and with a process for the preparation of said haptens. (author)

Peptide-DNA conjugates as tailored bivalent binders of the oncoprotein c-Jun.

Science.gov (United States)

Pazos, Elena; Portela, Cecilia; Penas, Cristina; Vázquez, M Eugenio; Mascareñas, José L

2015-05-21

We describe a ds-oligonucleotide-peptide conjugate that is able to efficiently dismount preformed DNA complexes of the bZIP regions of oncoproteins c-Fos and c-Jun (AP-1), and therefore might be useful as disrupters of AP-1-mediated gene expression pathways.

Automation of radioimmunoassay

International Nuclear Information System (INIS)

Yamaguchi, Chisato; Yamada, Hideo; Iio, Masahiro

1974-01-01

Automation systems for measuring Australian antigen by radioimmunoassay under development were discussed. Samples were processed as follows: blood serum being dispensed by automated sampler to the test tube, and then incubated under controlled time and temperature; first counting being omitted; labelled antibody being dispensed to the serum after washing; samples being incubated and then centrifuged; radioactivities in the precipitate being counted by auto-well counter; measurements being tabulated by automated typewriter. Not only well-type counter but also position counter was studied. (Kanao, N.)

Some methodic aspects in optimizing the radioimmunoassay of β-endorphin

International Nuclear Information System (INIS)

Rueckert, R.I.; Hoffmann, Y.; Rohde, W.

1986-01-01

A specific double antibody radioimmunoassay (RIA) for human β-endorphin (β-EP) using an antibody to synthetic β/sub h/-endorphin was established. This antibody cross-reacted with β-lipotropin (β-LPH) at 42% on molar basis and allowed a usable range of 20 pg to 4 ng of β-endorphin per ml in the assay. Comparing the efficiency of the conventional extraction procedures under various conditions using Corning glass, Vycor glass, QUSO G-32, silicic acid and controlled pore glass 75, the optimal result was obtained by Corning glass, with a recovery rate of more than 80%. The most simple and rapid method with an extraction efficiency of more than 90% was found to be the extraction by use of Sep-Pak C18 cartridges. The separation of β-EP from β-LPH was studied using Sephadex G-50, G-75, G-100 and Bio-Gel P-60 columns and different elution media. The use of a Sephadex G-50 column (0.9 x 55 cm) and elution with 0.1 N acetic acid-0.05% HSA gave the best result. The reliability of the radioimmunoassay was shown under physiological and pathophysiological conditions. (author)

The Association between Newborn Regional Body Composition and Cord Blood Concentrations of C-Peptide and Insulin-Like Growth Factor I.

Directory of Open Access Journals (Sweden)

Emma M Carlsen

Full Text Available Third trimester fetal growth is partially regulated by C-peptide and insulin-like growth factor I (IGF-I. Prenatal exposures including maternal obesity and high gestational weight gain as well as high birth weight have been linked to subsequent metabolic disease. We evaluated the associations between newborn regional body composition and cord blood levels of C-peptide and IGF-I.We prospectively included obese and normal-weight mothers and their newborns; cord blood was collected and frozen. Analyses of C-peptide and IGF-I were performed simultaneously, after recruitment was completed. Newborn regional body composition was assessed with dual-energy X-ray absorptiometry scanning (DXA within 48 hours of birth.Three hundred thirty-six term infants were eligible to participate in the study; of whom 174 (52% infants had cord blood taken. Total, abdominal and arm and leg fat mass were positively associated with C-peptide (p < 0.001. Arm and leg fat mass was associated with IGF-I concentration: 28 g [95% confidence interval: 4, 53] per doubling of IGF-I. There was no association between total or abdominal fat mass and IGF-I. Fat-free mass was positively associated with both C-peptide (p < 0.001 and IGF-I (p = 0.004.Peripheral fat tissue accumulation was associated with cord blood C-peptide and IGF-I. Total and abdominal fat masses were related to C-peptide but not to IGF-I. Thus, newborn adiposity is partially mediated through C-peptide and early linear growth is associated with IGF-I.

Fluorescent turn-on determination of the activity of peptidases using peptide templated gold nanoclusters

International Nuclear Information System (INIS)

Luo, Junjun; Wang, Liqiang; Zeng, Ke; Shen, Congcong; Qian, Pin; Yang, Minghui; Rasooly, Avraham; Qu, Fengli

2016-01-01

The fluorescence intensity of gold nanoclusters (AuNCs) is inversely related to the length of a peptide immobilized on its surface. This finding has been exploited to design a turn-on fluorescent method for the determination of the activity of peptidase. The β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) was chosen as a model peptidase. BACE1 cleaves the peptide substrates on AuNCs, and the fluorescence intensity of the AuNCs (at exCitation/emission wavelengths of 320/405 nm) carrying the rest of the cleaved peptide is significantly higher than that of the AuNCs with uncleaved peptide. Transmission electron microscopy revealed a decrease in the size of the AuNCs which is assumed cause fluorescence enhancement. The assay was applied to the determination of BACE1 activity in spiked cell lysates, and recoveries were between 96.9 and 104.0 %. (author)

[Regulatory effect of Erbao granules on brain-gut peptide in juvenile animal model of anorexia].

Science.gov (United States)

Zhang, Y; Du, Y; Wang, S

2000-10-01

To study the regulatory effect of Erbao granules (EBG) on central and peripheral brain-gut peptide in juvenile animal model of anorexia. Juvenile rat model of anorexia was established by imitating the major cause of infantile anorexia and treated with EBG. The cholocystokinin-octapeptide (CCK-8) and beta-endorphin (beta-EP) concentration in hypothalamus, antrum pyloricum and peripheral blood were examined by radioimmunoassay. CCK-8 concentration in hypothalamus and plasma in the model rats increased (P anorexia model.

Relation of muscle indices with metabolic parameters and C-peptide in type 2 diabetes mellitus

International Nuclear Information System (INIS)

Tuzun, S.; Oner, C.; Dabak, M.R.; Kasikci, H.O.; Sargin, M.

2017-01-01

Objective: To assess the relation between bioimpedance measurements and metabolic parameters and C-peptide in patient with type 2 diabetes mellitus (DM). Study Design: Cross-sectional study. Place and Duration of Study: Kartal Dr Lutfi Kirdar Training and Research Hospital, Pendik Kaynarca Diabetes Center, Exercise and Metabolism Unit, between January and March 2015. Methodology: Patients with DM, aged less than 65 years, were assessed for bioimpedance analysis, fasting plasma glucose (FPG), HbA1c, C-peptide levels, triglyceride levels, LDL-cholesterol, and HDL-cholesterol levels. Skeletal muscle index, total muscle index, skeletal muscle percentage, and total muscle percentage were used for muscle-related analyses. Mann-Whitney U-test or independent t-test were used to compare differences between two independent groups. Pearson correlation test or Spearman correlation test were used to find out correlation between variables. Results: A total of 359 DM patients were enrolled in the study. Mean age was 51.6+-8.0 years, and 278 (77.7%) of the participants were females. After adjusting age and gender variables, there was no relation between muscle-related measurements and FPG, triglyceride, LDL-cholesterol (p>0.05). However, there was muscle-related indexes (MRI) positively correlation with C-peptide and inversely associated with HDL-cholesterol (p<0.05). Conclusion: Muscle-related indices positively correlated with C-peptide, which showed endogenous insulin reserve. (author)

Apparatus for use in radioimmunoassays

International Nuclear Information System (INIS)

Chen, C-H.; Tsay, H-M.; Heyer, R.E.

1979-01-01

Apparatus for solid-phase antibody separation techniques used in radioimmunoassays is described in this invention. It consists of a rectangular prism tray with multiple wells protruding into its interior from one side. Near the base of the tray is an orifice used for creating evacuated condition within the structure. At the base of each well there is an orifice of such size and shape as to retain an aqueous liquid under given pressure conditions but permit the evacuation of this liquid at reduced pressure. The outlet of these orifices is in the shape of an inverted conical frustrum. Each of the wells contains an antibody coated disc of porous cellulose paper surrounded by a plastic support. The porous nature of the cellulose paper ensures contact between the antibody coating and the antigen. The use of antibody coated porous cellulose paper in combination with the vacuum operated apparatus simplifies the manipulative steps whilst still maintaining the sensitivity of the radioimmunoassay. It also obviates the need for aspiration and thus lessens the risk of contamination from one sample to another. (UK)

Conjugated oestrogen during the menstrual cycle measured by a direct radioimmunoassay with an antiserum prepared against oestradiol-17-glucosiduronate-(C-6)-BSA conjugate

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Honjo, H.; Otsubo, K.; Yasuda, J.; Kitawaki, J.; Okada, H. (Department of Obstetrics and Gynaecology, Kyoto Prefectural University of Medicine, Kyoto); Ohkubo, T.; Nambara, T. (Pharmaceutical Institute, Tohoku University, Sendai, Japan)

1984-01-01

Early morning and 24 h urine samples and serum were collected daily throughout the menstrual cycle in women. Urinary oestradiol-17-glucosiduronate (E/sub 2/-17G) was measured with a direct radioimmunoassay whose antiserum has been prepared against E/sub 2/-17-G-(C-6)-bovine serum albumin conjugate and was very specific. On the average, E/sub 2/-17-G in early morning and 24 h urine samples showed a prominent peak one day before the peak of urinary LH. The time relationship between these urinary E/sub 2/-17-G and serum E/sub 2/ levels and peaks was also investigated.

Radioimmunoassay and related procedures in medicine

International Nuclear Information System (INIS)

1978-01-01

symposium provided opportunities for an exchange of information of all of these topics. The introductory lecture by Dr. W.D. Odell of the USA, entitled 'We Don't Look at Hormones the Way We Used to', drew attention to the very great conceptual changes that have arisen in relation to hormones in recent years, largely as a result of the applications of radioassay procedures in endocrinology. Dr. Odell emphasized that bioassay, radioimmunoassay, radioreceptor assay and the consideration of molecular structure provide four distinct approaches to the quantification of hormones and that it is not to be expected that these approaches will yield comparable results. However, the results taken together may permit an understanding of disease not previously possible. Individual sessions on assay methodology were devoted to reagents, automation, data analysis, and alternatives to radioassay. Individual sessions on applications were devoted to assays for steroids and other small molecules, assays for thyroid-related hormones and assays for peptides. Each session was introduced by an invited review paper summarizing recent advances in the particular subject field. The subject of assay standardization and quality control was considered at length in two round-table discussion sessions, one on assay design, standardization and within laboratory quality control and one on external quality control, arranged in co-operation with the World Health Organization Special Programme of Research in Human Reproduction. These sessions evoked much interest and the importance of the concepts and techniques presented therein in the development of effective assay services was recognized. The proceedings of the symposium, comprising the papers presented and the edited discussions, will be published by the IAEA. (author)

Radioimmunoassay and related procedures in medicine

Energy Technology Data Exchange (ETDEWEB)

NONE

1978-02-15

symposium provided opportunities for an exchange of information of all of these topics. The introductory lecture by Dr. W.D. Odell of the USA, entitled 'We Don't Look at Hormones the Way We Used to', drew attention to the very great conceptual changes that have arisen in relation to hormones in recent years, largely as a result of the applications of radioassay procedures in endocrinology. Dr. Odell emphasized that bioassay, radioimmunoassay, radioreceptor assay and the consideration of molecular structure provide four distinct approaches to the quantification of hormones and that it is not to be expected that these approaches will yield comparable results. However, the results taken together may permit an understanding of disease not previously possible. Individual sessions on assay methodology were devoted to reagents, automation, data analysis, and alternatives to radioassay. Individual sessions on applications were devoted to assays for steroids and other small molecules, assays for thyroid-related hormones and assays for peptides. Each session was introduced by an invited review paper summarizing recent advances in the particular subject field. The subject of assay standardization and quality control was considered at length in two round-table discussion sessions, one on assay design, standardization and within laboratory quality control and one on external quality control, arranged in co-operation with the World Health Organization Special Programme of Research in Human Reproduction. These sessions evoked much interest and the importance of the concepts and techniques presented therein in the development of effective assay services was recognized. The proceedings of the symposium, comprising the papers presented and the edited discussions, will be published by the IAEA. (author)

Synthetic lung surfactants containing SP-B and SP-C peptides plus novel phospholipase-resistant lipids or glycerophospholipids

Directory of Open Access Journals (Sweden)

Robert H. Notter

2016-10-01

Full Text Available Background This study examines the biophysical and preclinical pulmonary activity of synthetic lung surfactants containing novel phospholipase-resistant phosphonolipids or synthetic glycerophospholipids combined with Super Mini-B (S-MB DATK and/or SP-Css ion-lock 1 peptides that replicate the functional biophysics of surfactant proteins (SP-B and SP-C. Phospholipase-resistant phosphonolipids used in synthetic surfactants are DEPN-8 and PG-1, molecular analogs of dipalmitoyl phosphatidylcholine (DPPC and palmitoyl-oleoyl phosphatidylglycerol (POPG, while glycerophospholipids used are active lipid components of native surfactant (DPPC:POPC:POPG 5:3:2 by weight. The objective of the work is to test whether these novel lipid/peptide synthetic surfactants have favorable preclinical activity (biophysical, pulmonary for therapeutic use in reversing surfactant deficiency or dysfunction in lung disease or injury. Methods Surface activity of synthetic lipid/peptide surfactants was assessed in vitro at 37 °C by measuring adsorption in a stirred subphase apparatus and dynamic surface tension lowering in pulsating and captive bubble surfactometers. Shear viscosity was measured as a function of shear rate on a Wells-Brookfield micro-viscometer. In vivo pulmonary activity was determined by measuring lung function (arterial oxygenation, dynamic lung compliance in ventilated rats and rabbits with surfactant deficiency/dysfunction induced by saline lavage to lower arterial PO2 to <100 mmHg, consistent with clinical acute respiratory distress syndrome (ARDS. Results Synthetic surfactants containing 5:3:2 DPPC:POPC:POPG or 9:1 DEPN-8:PG-1 combined with 3% (by wt of S-MB DATK, 3% SP-Css ion-lock 1, or 1.5% each of both peptides all adsorbed rapidly to low equilibrium surface tensions and also reduced surface tension to ≤1 mN/m under dynamic compression at 37 °C. However, dual-peptide surfactants containing 1.5% S-MB DATK + 1.5% SP-Css ion-lock 1 combined with

Local preparation and evaluation of liquid phase radioimmunoassay for determination of human serum cortisol

International Nuclear Information System (INIS)

Sallam, Kh.M.; El-Bayoumy, A.S.A.; Ebeid, N.H.; Michael, E.; Zein, N.; Elfarargy, Ah.F.

2017-01-01

The main objective of the present study was the preparation of the primary reagents of cortisol radioimmunoassay (RIA) using liquid phase double antibody technique. Three basic components were prepared and characterized to obtain valid and accurate system. These components were polyclonal anti-cortisol antibody, "1"2"5I-cortisol RIA tracer and cortisol standards. Cortisol requires conjugation step to be real antigen. Therefore, in this study this mandatory conjugation step was performed & characterized. Then formulation, optimization and validation of this liquid phase RIA technique were carried out. This assay is precise, specific and sensitive enough for using as a diagnostic tool for the adrenal cortex status. (author)

Development of a radioimmunoassay for circulating levels of gonadotropin releasing hormone

International Nuclear Information System (INIS)

Moodbidri, S.B.; Joshi, L.R.; Sheth, A.R.; Rao, S.S.

1976-01-01

A specific and sensitive radioimmunoassay system has been developed for measuring gonadotropin releasing hormone (GnRH) in unextracted human serum. Circulating levels of GnRH, LH and FSH were determined in 37 serum samples obtained from twenty normal healthy women on different days of the menstrual cycle. GnRH and LH but not FSH exhibited similar patterns during the menstrual cycle. 125 I-labelled GnRH was used in the RIA system. (author)

Development and clinical application of human gastrin radioimmunoassay

International Nuclear Information System (INIS)

Ginabreda, M.G.P.; Borghi, V.C.; Bettarello, A.

1988-08-01

The determination of human gastrin levels in the blood is very important for diagnosis of gastrointestinal disorders. This work describes the radioimmunoassay of gastrin developed according to Russell et al. and its clinical application measuring fasting levels of this hormone in normal subjects, gastrectomized, chagasics, patients with chronic renal failure (CRF), pernicious anemia (PA) and Zollinger-Ellison syndrome (ZES). Synthetic human gastrin was used for radioiodination and as standard, while the specific antibody was raised in rabbits. Gastrin was radioiodinated by a modification of the chloramine T technique and purified by anion exchange chromatography in QAE-Sephadex A-25 to a specific activity around 200 uCi/ug. The assays were performed by incubation of 125 I-gastrin, standard gastrin (zero to 500 pmol/l) or unknown samples with the antiserum for 4 days at 4 0 C. The antibody bound and free 125 I-gastrin was separated by adsorption of the latter to the charcoal. The basal gastrin values of normal subjects ranged from 2 to 74 pmol/l, being these levels higher in the chagasics (from 6 to 261 pmol/l). Higher levels of gastrin were determined in patients with CRF (from 12 to 350 pmol/l), PA (from 160 to 680 pmol/l) and with ZES(1010 pmol/l), while very low levels were confirmed in gastrectomized (from 1 to 8 pmol/l). (author) [pt

Liquid-phase and solid-phase radioimmunoassay with herpes simplex virus type 1 nucleocapsids

International Nuclear Information System (INIS)