Radioimmunoassay for 3,3',5'-triiodothyronine (reverse T3, R-T3) in unextracted human serum

Highly specific antibodies against 3,3',5'-triiodothyronine (reverse T3, R-T3) have been produced in rabbits. The crossreaction with T4 is about 0.05%. A radioimmunoassay for R-T3 in unextracted serum was developed. ANS is used for blocking the binding of tracer and endogenous R-T3 to TBG. The sensitivity to the assay is 0.06 ng/ml plasma. The mean normal R-T3 concentration is 0.20 ng/ml. Thyrotoxic patients show elevated levels; in most hypothyroid patients R-T3 concentrations are below the detection limit.     

Changes in the binding capacity of thyroxine-binding globulin (TBC), of total thyroxine (T4), of the free thyroxine index (FT4-I) and of thyrotropin (TSH) during normal pregnancy and in hydatidiform mole

TBC-index and total serum thyroxine were measured in 100 healthy nonpregnant and in 163 pregnant women during the 8. and 41. weeks of gestation. The free thyroxine index was calculated. The TBC-index was found to be elevated in pregnant women and rose continously with duration of pregnancy. The amount of total serum thyroxine was greater in pregnant women (p less than 0,01) without difference between early and late pregnancy. The free thyroxine index decreased continously during pregnancy (p less than 0,01). Serum TSH level were elevated during the first two trimesters of pregnancy. At the third trimester the TSH level were found within the normal range. In patients with hydatidiform mole TSH, total thyroxine, FT4-index, ETR-index as well as TSH levels were increased.     

Immunoassay for thyroxine (T4) in serum using capillary electrophoresis and micromachined devices

As part of our ongoing effort to develop electrophoretic assay technology for clinical diagnostics, we describe a competitive immunoassay for the determination of serum thyroxine (T4) based on electrophoresis and laser induced fluorescence (LIF). Measurements of total T4 are useful for the clinical evaluation of thyroid function. A fluorescein thyroxine conjugate was utilized in conjunction with a polyclonal antibody preparation as assay reagents. Capillary electrophoresis (CE) conditions tolerant of the direct injection of serum without extraction or other sample preparation steps were developed and used for quantitation of total T4 in serum. We have been exploring the use of micromachined devices with arrays of channels for high assay throughput. Our assay protocol was carried in a microchip format. The results illustrate that gains in speed can be additionally achieved, with the electrophoretic separation of free from bound labelled T4 being performed in about 15 s for serum samples.     

Triiodothyronine (T3) and thyroxine (T4) levels in Rana curtipes during development and metamorphosis

During premetamorphosis, levels of circulating triiodothyronine (T3) and thyroxine (T4) were below the limits of detection of RIA. They became detectable in late prometamorphic stages. A gradual increase in T3 and T4 was observed during this period. A sharp rise in hormone levels was apparent at the onset of metamorphic climax. Peak levels of both hormones were found at Taylor-Kollros stage XXI. The T3 reached a peak level of 101.4 ng/dl, about 3 fold increase over the level at prometamorphosis. Thereafter the circulating hormones (particularly T4) decreased rapidly and reached levels similar to prometamorphic stages. Significant high levels of thyroid hormones (T3 and T4) in metamorphic climax suggest that like other anurans, elevation of these hormones is required for normal metamorphosis in R. curtipes tadpoles.     

A comparison of human prothrombin, factor IX (Christmas factor), factor X (Stuart factor), and protein S

Human prothrombin, factor IX, and factor X have been idolated in high yield and characterized as the their amino-terminal sequence, molecular weight, amino acid composition, and migration in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An additional human plasma protein, called protein S, has also been purified and its properties have been compared with those of prothrombin, factor IX, and factor X. Prothrombin (mol wt 72 000), factor IX (mol wt 57 000), and protein S (mol wt 69 000) are single-chain glycoproteins, while factor X (mol wt 59 000) is a glycoprotein composed of two polypeptide chains held together by a disulfide bond(s). The amino-terminal sequence of the light chain of human factor X is homologous with prothrombin, factor IX, and protein S. The heavy chain of human factor X is slightly larger than the heavy chain of bovine factor X and differs from bovine factor X in its amino-terminal sequence.     

Expression of HIV env gene in a human T cell line for a rapid and quantifiable cell fusion assay

Human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins present at the surface of infected cells are known to mediate fusion with CD4-positive target cells. In this study we have developed a novel Env-expressing cell line for investigating the fusion process in a biologically significant system. Cell surface expression of the HIV-1 env gene, isolated from the highly fusogenic strain SF33, was obtained in the CD4-negative T cell line A2.01. To render the system versatile and efficient, HIV-1 regulatory proteins Tat and Rev were supplied in trans. The presence of Env at the cell surface was shown by cytofluorometry and immunofluorescence and precursor processing of gp160 to gp120/gp41 was demonstrated by Western blot. The fusion capacity of A2.01-Env cells was assessed by coculture with CD4-positive T lymphocytes or the fusion indicator cell line, HeLa-CD4-LTR-beta-Gal. By coincubation with CD4-positive T cells such as SupT1, A2.01-Env cells were observed to mediate rapidly numerous well-defined syncytia in a reproducible fashion. By expressing Tat, they also had the capacity to trans-activate the LTR-linked reporter beta-Gal gene following fusion with HeLa-CD4-LTR-beta-Gal cells. The fusion-inhibiting anti-CD4 monoclonal antibodies Q425 and Q428 were used to block specifically Env-mediated fusion with CD4-positive cells and to demonstrate application of this system to the search for potential fusion-blocking agents. Our system thus offers a biologically significant model for studying fusion events with the advantages of being rapid, reproducible and versatile.     

A simple and rapid microSepharose assay for GAD65 and ICA512 autoantibodies in diabetes. Diabetes Incidence Study in Sweden (DISS)

Three scales, the Fake Bad Scale, the Fake Good Scale, and the Fake Bad-Fake Good scales were developed and evaluated with respect to their capacity to detect response manipulation on the Multiple Affect Adjective Check List-Revised. Cutting scores for each scale were cross-validated in two samples consisting of three groups: (1) college students simulating either "fake good" or "fake bad," (2) college students under standard instructions, and (3) psychiatric patients. Cutting scores on the three scales were compared with cutting scores established for the MAACL-R Dysphoria and Positive Affect plus Sensation Seeking. Analysis indicated that these scales were more accurate than the Positive Affect plus Sensation Seeking and the Dysphoria scales in detecting response manipulation.     

Determination of 3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid in human plasma by a simple and rapid high-performance liquid chromatography assay

In order to study the pharmacodynamic effects of drugs on dopamine and serotonin metabolism, a reversed-phase HPLC assay coupled with electrochemical detection (ECD) for measuring plasma concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) was developed. The system was operated isocratically using a mobile phase of aqueous 0.03 M KH2PO4 buffer containing 0.15 mM EDTA in methanol (8.75:1.25), with a final pH of 4.0. The flow rate was set at 1.5 mL/min, and potentials at +450 mV. Using a signal to noise ratio of > 3, the minimum detection limit assessed by direct on-column injection of a standard solution for DOPAC and 5-HIAA was < 1 pg. The assays were linear from basal concentrations (1-10 ng/mL) to 100 ng/mL. The intra- and interassay variations were < 10% and < 20%, respectively.     

Sensitive enzyme-linked immunosorbent assay for human serum amyloid A (SAA) and application to clearance study

Serum amyloid A (SAA), an apolipoprotein of high density lipoprotein (HDL), is a sensitive acute phase reactant. We established a sandwich type enzyme-linked immunosorbent assay for human SAA utilizing a monoclonal antibody and polyclonal antibodies. This assay was sensitive enough to detect SAA at 40 pg/ml. The use of nonionic detergent, Tween-20, in reaction buffer was essential to enhance specific binding of SAA to antibodies and reduce nonspecific binding to plastic. The values by this assay showed a good agreement with those by previously established latex agglutination immunoassay. Plasma clearance of human SAA was studied in mice by injection with SAA-rich human HDL and serial SAA measurement by the present assay. Half-life of injected SAA was 55 minutes, similar to mean of the reported value of murine SAA isotypes.     

Molecular modelling of (A4T4NN)n and (T4A4NN)n: sequence elements responsible for curvature

The molecular modelling program JUMNA has been used to investigate the origins of the strikingly different curvature of the two sequences, (A4T4NN)n and (T4A4NN)n. Gel electrophoresis and cyclisation studies have shown that only the former of these two sequences is significantly curved. By developing novel superhelical symmetry constraints we were able to study the energetic and structural aspects of polymeric DNA having a controlled curvature. The results obtained (which do not take into account specific hydration effects) correlate well with the experimental data and offer a molecular level explanation of curvature. Although curvature is found to be initiated by specific dinucleotide junctions, deformations spread to surrounding dinucleotide steps and, moreover, sequence effects beyond the dinucleotide level are observed.     

Photochemical labeling of human erythrocyte membrane proteins with radioiodinated 4-azidosalicylic acid derivatives of G(M3), G(D3), G(M1), and FucG(M1) gangliosides

Photoreactive gangliosides of high specific radioactivity may prove useful for studies on glycosphingolipid functions. We prepared 4-azidosalicylic acid (ASA) acylated derivatives of GM3, GD3, GM1, and FucGM1 gangliosides (gangliosides-ASA). Gangliosides-ASA were characterized by their TLC mobility, UV spectra, carbohydrate composition, and digestion with leech endoceramidase. After radioiodination to about 200 Ci/mmole gangliosides-ASA were used for photochemical labeling of human erythrocytes. Radioiodinated gangliosides-ASA were incorporated into erythrocytes in a time and concentration dependent manner, the kinetics and extent of incorporation being similar for all the gangliosides-ASA used. Radioiodinated gangliosides-ASA incorporated into erythrocytes were resistant to trypsin digestion while treatment with 1% BSA removed about 90% of the label. Incubation with cholera toxin protected radioiodinated GM1-ASA and, to a lesser extent, FucGM1-ASA but not GM3-ASA and GD3-ASA, against removal with BSA. After photolysis about 40-50% of radioactivity was firmly bound to erythrocyte lipids and proteins. The ratio of lipid- to protein-bound radioactivity ranged from 2.2:1 to 3.2:1. Photolabeled proteins were analyzed by SDS/PAGE followed by autoradiography. Band 3 was the most extensively photolabeled protein with all the radioiodinated gangliosides-ASA used. DIDS, an inhibitor of band 3 protein activity, caused reduction in photolabeling of this protein by about 20%.     

Extrathyroidal conversion of thyroxine to 3,3',5'-triiodothyronine (reverse-T3) and to 3,5,3'-triiodothyronine (T3) in humans

In order to estimate the relative magnitude of the two alternative pathways of monodeiodination of thyroxine (T4) in adult humans, the metabolic clearance rates (MCR) and production rates (PR) of 3,3',5'-triiodothyronine (reverse-T3,rT3) and of 3,5,3'-triiodothyronine (T3) were determined in six euthyroid control subjects (C) and in five hypothyroid patients (H) receiving L-T4 as replacement therapy (0.15-0.3 mg/day). MCR was computed by a non-compartmental method of analysis from the plasma disappearance of 125I rT3 and 131I T3 during 72 h following simultaneous injection of tracers. PR was calculated from MCR and the serum concentration of rT3 and T3, respectively, determined by radioimmunoassay. In the H subjects, rT3 MCR averaged 97.1 +/- 12.8 (SD) 1/day and rT3 PR, 34.3 +/- 12.8 microng/day; T3 MCR was 28.7 +/- 6.1 1/day and T3 PR, 20.3 +/- 6.6 microng/day (all corrected to 70 kg body weight). These results were not significantly different from those in the control group; rT3 MCR 104 +/- 24 1/day, rT3 PR 33.0 +/- 9.2 microng/day; T3 MCR 24.0 +/- 5.9, T3 PR 24.2 +/- 4.1. The proportionof total triiodothyronine (rT3 averaged 62% in H patients and was similar (57%) in the C group. The results obtained in the H subjects indicate that the production of rT3 is a major route of T4 metabolism, equal to or exceeding that of T3. From the close agreement between the mean values for rT3 PR in the C and H groups it is concluded that most, if not all of the rT3 produced in normal humans is derived by extrathyroidal conversion from T4.     

Lack of germ-line mutations of CDK4, p16(INK4A), and p15(INK4B) in families with glioma

Gliomas are tumors of the central nervous system that may be inherited in some patients. The gene(s) responsible for the clustering of gliomas in families have not yet been identified. Molecular studies of sporadic high-grade gliomas have revealed mutations or deletions of the genes encoding the protein kinase inhibitors p16(INK4A) and p15(INK4B) in a large proportion of tumors. Moreover, those tumors without deletions frequently display gene amplification and/or over-expression of mRNA encoding the protein kinase cdk4. We hypothesized that germ-line mutations in the p16(INK4A), p15(INK4B), or CDK4 genes might contribute to some cases of familial gliomas. To address this issue, we analyzed 36 kindreds with a predisposition to glial tumors. Genomic DNA from index members of these families was screened by PCR-single-strand conformational polymorphism analysis. We did not detect any functional mutations in the p16(INK4A), p15(INK4B), or CDK4 genes, although two individuals did have a previously described A140T polymorphism in p16(INK4A). Thus, despite the association between the sporadic forms of high-grade glioma and abnormalities of p16(INK4A), p15(INK4B), or CDK4, we found no evidence that germ-line mutations in the coding region of these three genes predispose to inherited glial tumors.     

Metabolic efficacy of preprandial administration of Lys(B28), Pro(B29) human insulin analog in IDDM patients. A comparison with human regular insulin during a three-meal test period

OBJECTIVE: The objective of this study was to compare the efficacy of the rapid-acting Lys(B28), Pro(B29) human insulin analog, insulin lispro, with currently available short-acting human insulin in a multiple injection therapy (MIT) regimen with respect to blood glucose and plasma insulin profiles and to serum metabolites (lactate, free fatty acids, glycerol, and beta-hydroxybutyrate) in 12 well-controlled type 1 diabetic subjects (8 male, HbA1c 6.8 +/- 0.9% [mean +/- SD]). RESEARCH DESIGN AND METHODS: After a run-in period of 4 weeks, patients were treated with either lispro at mealtime or human insulin 30 min before the meal for two periods of 4 weeks in a randomized open-label crossover study. Intermediate-acting insulin (NPH insulin) was given at bedtime. At the end of both study periods, metabolic profiles were assessed from 10:00 P.M. to 7:00 P.M. the next day. RESULTS: During the treatment periods, glycemic control was stable during lispro but improved during human insulin (delta HbA1c lispro 0.1 +/- 0.48, NS; human insulin -0.41 +/- 0.34%, P < 0.05). Glucose excursions, as measured by the incremental AUC, during the day and for the 2-h postprandial periods, were lower, although not significantly, for lispro. Insulin profiles demonstrated a faster rise after administration of lispro as compared with human insulin, peaking at 61 +/- 11.9 and 111 +/- 48.1 min (P < 0.01). Glycerol levels showed a slight increase before lunch and dinner, suggestive of enhanced lipolytic activity and compatible with the lower insulin levels. CONCLUSIONS: Lispro insulin applied in an MIT regimen creates more physiologic insulin profiles and tends to lower the glycemic excursions during the day compared with short-acting insulin. The analog can be applied safely in an MIT regimen, with mealtime intervals up to 5 h.     

Long-term followup of all patients with muscle invasive (stages T2, T3 and T4) bladder carcinoma in a geographical region

PURPOSE: We studied the relationship between long-term survival and treatment of stages T2, T3 and T4 bladder carcinoma in an unselected patient population. MATERIALS AND METHODS: A total of 680 patients with the initial diagnosis of bladder carcinoma in 1987 to 1988 in Western Sweden was prospectively registered and followed until 1994. Of these patients 107 had stage T2 to T3 and 41 had stage T4 disease. RESULTS: Of the patients with stage T2 to T3 disease 30 (mean age 66) underwent radical cystectomy, 33 (mean age 75) full dose radiotherapy and 44 (mean age 81) nonradical therapy (mainly transurethral resection of the bladder). The 5-year crude survival rates were 33, 15 and 14%, respectively. Of the patients with stage T4 disease 6 (mean age 61) underwent radical cystectomy, 9 (mean age 73) full dose radiotherapy and 26 (mean age 81) nonradical therapy (mainly transurethral resection of the bladder). All except 1 patient died of disease within 4 years. CONCLUSIONS: More than 60% of the patients in the cohort were considered unsuitable for radical cystectomy and their survival was poor, whether treated with full dose radiotherapy or transurethral resection of the bladder alone.     

Zinc(II) and copper(II) binding to serum albumin. A comparative study of dog, bovine, and human albumin

Metal binding strategies employing low molecular weight chelators and equilibrium dialysis were used to investigate several unresolved aspects of zinc and copper binding to serum albumin. Direct measurement of histidine binding to bovine serum albumin when the histidine is presented either as a metal-chelate or alone provides no evidence for an albumin-metal-histidine ternary complex. Using previously determined intrinsic constants for Zn(II) and Cu(II), we have measured zinc binding to bovine serum albumin in the presence of saturating amounts of copper. The results of these experiments unambiguously show that zinc and copper bind at separate noninteracting sites on this protein. The intrinsic constants for zinc and copper binding to dog serum albumin have been determined. Contrary to previous reports, we find that dog serum albumin has a specific high affinity site for copper, log10K 10.17 for Cu(II) compared to 6.85 for Zn(II) at the separate site.