Adult testosterone and calculated free testosterone reference ranges by tandem mass spectrometry.

BACKGROUND: Testosterone is measured for the investigation of female hyperandrogenism and male hypogonadism. Liquid chromatography-tandem mass spectrometry (tandem MS) is becoming the method of choice but comprehensive reference ranges are lacking. METHODS: Testosterone was measured by tandem MS on 90 healthy women, 67 young healthy men and pregnant women (59 first trimester and 60 second trimester). RESULTS: The male, male calculated free, first trimester and second trimester testosterone reference ranges (derived using the antilog of mean ± 1.96 SD of log transformed data) were 10.6-31.9, 0.23-0.63, 0.6-4.9 and 0.9-4.9 nmol/L, respectively. The female testosterone upper reference range limit, derived non-parametrically from the 97.5th centile, was <1.7 nmol/L. CONCLUSIONS: We have derived tandem MS testosterone reference ranges to support clinical services.

Iron-monosulfide oxidation in natural sediments: resolving microbially mediated S transformations using XANES, electron microscopy, and selective extractions.

Iron-monosulfide oxidation and associated S transformations in a natural sediment were examined by combining selective extractions, electron microscopy and S K-edge X-ray absorption near-edge structure (XANES) spectroscopy, The sediment examined in this study was collected from a waterway receiving acid-sulfate soil drainage. It contained a high acid-volatile sulfide content (1031 micromol g(-1)), reflecting an abundance of iron-monosulfide. The iron-monosulfide speciation in the initial sediment sample was dominated by nanocrystalline mackinawite (tetragonal FeS). At near-neutral pH and an 02 partial pressure of approximately 0.2 atm, the mackinawite was found to oxidize rapidly, with a half-time of 29 +/- 2 min. This oxidation rate did not differ significantly (P < 0.05) between abiotic versus biotic conditions, demonstrating that oxidation of nanocrystalline mackinawite was not microbially mediated. The extraction results suggested that elemental S (S8(0)) was a key intermediate S oxidation product Transmission electron microscopy showed the S8(0) to be amorphous nanoglobules, 100-200 nm in diameter. The quantitative importance of S8(0) was confirmed by linear combination XANES spectroscopy, after accounting for the inherent effect of the nanoscale S8(0) particle-size on the corresponding XANES spectrum. Both the selective extraction and XANES data showed that oxidation of S8(0) to SO4(2-) was mediated by microbial activity. In addition to directly revealing important S transformations, the XANES results support the accuracy of the selective extraction scheme employed here.

Why do fiddler crabs build chimneys?

Chimneys are mud mounds built by fiddler crabs that encircle the entrance to their burrow. Their function in many species is unknown. In Uca capricornis, crabs of both sexes and all sizes build chimneys, but females do so disproportionately more often. There are no differences in the immediate physical or social environments between crabs with and without a chimney. Chimney owners spend less time feeding and more time underground than non-owners. We show experimentally that burrows with a chimney are less likely to be located by an intruder. It is possible that some crabs construct chimneys around their burrow to conceal the entrance and reduce the risk of losing it to an intruder.

A physical map of 30,000 human genes.

A map of 30,181 human gene-based markers was assembled and integrated with the current genetic map by radiation hybrid mapping. The new gene map contains nearly twice as many genes as the previous release, includes most genes that encode proteins of known function, and is twofold to threefold more accurate than the previous version. A redesigned, more informative and functional World Wide Web site (www.ncbi.nlm.nih.gov/genemap) provides the mapping information and associated data and annotations. This resource constitutes an important infrastructure and tool for the study of complex genetic traits, the positional cloning of disease genes, the cross-referencing of mammalian genomes, and validated human transcribed sequences for large-scale studies of gene expression.

Patterns of serum CEA fall after hepatic arterial chemotherapy as sole therapy and combined with cryotherapy for colorectal metastases.

BACKGROUND: Hepatic artery chemotherapy (HAC) and cryoablation are treatments for unresectable liver metastases from colorectal carcinomas. Our centre has previously published data that describe survival statistics of patients after each of these treatments. It has also been established that serial serum carcinoembryonic antigen (CEA) concentrations may be used to monitor disease progress, and that the magnitude of fall is prognostic for both treatments. The pattern of fall of CEA following cryotherapy and regional chemotherapy has not previously been compared. METHODS: In this study, we examined 26 HAC patients and 24 cryotherapy patients. RESULTS: The mean percentage of the pre-treatment CEA concentration for the HAC group was 60.5% at 50 days and 29.4% at 150 days, and for the cryotherapy group 24.9% at 50 days and 24.3% at 150 days. Calculating the difference between means revealed a significantly different mean fall in the cryotherapy group at 50 days (P < 0.001) and a difference in mean fall at 150 days (P > 0.1) which was not significant. In patients who responded to hepatic artery chemotherapy, the eventual CEA fall was very similar in magnitude. CONCLUSIONS: The pattern of fall of CEA differs in these two treatments.

Isolation and characterization of infective and non-infective clones of Leishmania tropica.

Cloning by limit dilution of an isolate of Leishmania tropica (LRC-L137) that is infective for mice resulted in 7 stable clones, only one of which was infective in BALB/c mice. Three of the non-infective clones that were examined for survival in BALB/c macrophages in vitro seemed to be killed more readily, suggesting failure to establish in macrophages as the basis for non-infectivity in vivo. Promastigotes from three non-infective clones and one infective clone were biosynthetically labelled or surface radioiodinated, and the detergent lysates were analyzed by 2-dimensional gel electrophoresis. The pattern of the radiolabelled cytoplasmic and membrane proteins of promastigotes from all L. tropica clones was similar, with minor differences. All clones as well as the uncloned population bound to the same extent to a series of lectins with galactose and N-acetylgalactosamine as specificities. They also bound in a solid-phase radioimmunoassay to 9 monoclonal antibodies raised against the uncloned L. tropica (LRC-L137). The genetic characterization of four L. tropica clones was attempted by analysis of their isolated kinetoplast DNA. The clones from two schizodemes since they possess kinetoplast DNAs which exhibit similar restriction endonuclease fingerprints and show extensive DNA sequence homology, suggesting that the four clones are closely related and that the non-infective variants may be derived from the infective presumptive parental clone L137-7-121. Further characterization of the clones of L. tropica should allow a better understanding of the genetic basis of parasite virulence in cutaneous leishmaniasis.

Sj23, the target antigen in Schistosoma japonicum adult worms of an immunodiagnostic hybridoma antibody.

An IgG2a mouse hybridoma-derived antibody (designated I.134) has been identified which binds to Schistosoma japonicum adult worms and which has immunodiagnostic potential (for detection of antibody) in schistosomiasis japonica in the Philippines. The target epitope of this hybridoma antibody is contained in a 23 000 molecular weight protein of adult worms as analysed by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis of immunoprecipitates and a gel overlay technique. This adult worm antigen has been labelled biosynthetically using 35S-methionine as well as exogenously using lactoperoxidase-catalysed radioiodination and the Bolton and Hunter reagent with intact worms. As anticipated, the low molecular weight protein antigen (designated Sj23) appears to be one of several major immunogenic proteins of worms which induce antibodies in infected Philippine patients.

Lung granulomatous hypersensitivity to eggs of Schistosoma japonicum in mice analysed by a radioisotopic assay and effects of hybridoma (idiotype) sensitization.

The radioisotopic assay for acute granulomatous hypersensitivity (AGH) to eggs of Schistosoma japonicum in mice sensitized with eggs in adjuvant has been examined in the high responder strain. C57BL/6. Responsiveness is expressed as the lung-kidney ratio of radioactivity in mice challenged intravenously with eggs and injected with 125I-iododeoxyuridine. Eggs vary in their AGH sensitizing and eliciting potency; eggs proven to be superior in the circumoval precipitation (COP) test for detection of human serum anti-S. japonicum antibodies are superior in the C57BL/6 AGH assay. CBA/H are non responders and BALB/c are low to intermediate responders and are thus different from C57BL/6 mice. Short-term infected CBA/H mice are low COP antibody responders relative to infected C57BL/6 and titres of IgM anti-egg antibodies are low in the CBA/H strain as determined in a solid-phase radioimmunoassay (RIA). Following egg sensitization, CBA/H mice are also lower responders than C57BL/6 mice in terms of antibodies with the specificity of a COP-positive IgM hybridoma-derived antibody, P.41, measured in a competitive RIA. No evidence has been obtained that alteration of the response to the target epitope of P.41 alters the responsiveness of C57BL/6 mice to S. japonicum eggs. Thus, large amounts of injected P.41 antibody do not alter lung AGH and induced anti-idiotype responses to the P.41 protein do not influence AGH in egg-sensitized C57BL/6 mice. However, immunization of C57BL/6 mice with another IgM anti-schistosome hybridoma antibody, 1.39, results in partial inhibition of lung AGH responsiveness. The nature of the effect of 1.39 immunization on AGH to eggs remains unknown, but further analysis of the phenomenon may lead to novel approaches to the control of granulomatous inflammatory disease in high responders.

Stage-specific, strain-specific, and cross-reactive antigens of Leishmania species identified by monoclonal antibodies.

The fusion of NS-1 myeloma cells with spleen cells from mice chronically infected with Leishmania tropica resulted in nine clones of hybridomas producing monospecific antibodies to membrane antigens of L. tropica. One of the antibodies (L-5-85) bound specifically to the promastigote form of the parasite, and the remaining eight recognized antigens shared by the promastigote and amastigote of L. tropica. Four of the antibodies (L-5-16, L-5-34, L-5-44, and L-2-3F11) detected parasite antigens on the surface of L. tropica-infected macrophages. Common antigens shared by L. tropica, L. mexicana, and L. donovani were identified as well as one antigen apparent on most Leishmania spp. and present also in Crithidia fasciculata. Two monoclonal antibodies (L-5-27 and L-5-41) were found to bind only to strains of L. tropica from simple cutaneous leishmaniasis. A special property shared by these two antibodies was the inhibition of parasite growth in macrophages in vitro.

Murine hybridoma-derived antibodies in the processing of antigens for the immunodiagnosis of hydatid (Echinococcus granulosus) infection in sheep.

Mice experimentally infected with hydatid parasite Echinococcus granulosus (secondary echinococcosis), were used as spleen cell donors for hybridoma production. Two hybridomas were produced which secreted antibody with anti-E. granulosus cyst fluid (EgCF) activity. Radioimmunoassays comparing the binding of these hybridoma-derived antibodies to E. granulosus versus several other antigen preparations from sheep parasites showed that the antibodies had a high degree of specificity for the hydatid parasite. However, using a panel of clinically defined sheep sera in a competitive radio-immunoassay, the binding of the hybridoma-derived antibodies to EgCF was inhibited strongly by sera from sheep infected with the common parasites Fasciola hepatica and Taenia hydatigena. When the hybridoma-derived antibodies were conjugated to CNBr-activated Sepharose and the crude EgCF applied to the affinity column, the "run through' antigen preparation showed a significant increase in specificity for experimental E. granulosus infection. A useful means of applying the hybridoma technology in the development of new immunodiagnostic reagents may be to select those murine hybridomas which produce high-affinity, cross-reacting antibodies and to use these antibodies in the processing of homologous antigen by affinity chromatography.