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Biomedical subjects

H Gerber

Publications and source records attributed to H Gerber.

At least 145 records · Page 8Linked to original sources

Cold follicles in a multinodular human goiter arise partly from a failing iodide pump and partly from deficient iodine organification.

To investigate whether the common cold follicles in human multinodular goiters are the consequence of a functional defect of the apical membrane peroxidase, a failure of the iodide transport system, or both deficiencies, we studied iodide accumulation and iodine organification in 30 fragments of a large multinodular goiter transplanted to nude mice and labeled with 125I. Transplants were frozen to -80 C immediately after removal to avoid diffusion of inorganic iodide. Autoradiographic assessment of over 1000 cryosections (exposed either at -20 C or after thawing and washing out unbound iodide) showed two types of cold follicles, namely those that failed to accumulate iodide and, therefore, did not organify iodine, and those that readily accumulated iodide but failed to bind it, suggesting a failure of apical membrane peroxidase. The two types of pathogenetically different cold follicles coexisted in an apparently randomly intermingled fashion throughout the whole goiter.

Aged↗

[Radioimmunoscintigraphy with a 99mTc-labeled F(ab')2 fragment of a monoclonal antibody (HMW-MAA 225.28S) in 71 patients with malignant melanoma].

In 71 patients with malignant melanoma 85 radioimmunoscintigraphies (RIS) with 99mTc-radiolabeled F(ab')2 fragments of a murine monoclonal antibody have been performed. The antibody is specific for an epitope of the HMW-MAA glycoprotein complex which is present in 90% of melanoma tissue samples. Sensitivity for RIS was 79% (73 metastatic sites out of a total of 92). 20 previously unknown lesions were found and there were also 2 false positives. Conventional staging procedures alone revealed 78% of the metastatic sites (72 of 92). No side effects were observed. RIS was especially useful for detection of lymph node metastases not found by conventional methods and is therefore considered complementary to conventional preoperative staging procedures.

Adult↗

Assessment of antithyroglobulin and antimicrosomal autoantibodies in patients with autoimmune thyroid disease: comparison of haemagglutination assay, enzyme-linked immunoassay and radioligand assay.

Four different assay systems for detection of antithyroglobulin (T-Ab) and thyroid antimicrosomal autoantibodies (M-Ab) were evaluated: two passive haemagglutination assays (PHA), an enzyme-linked immunoassay (ELISA) and a radioligand assay (RLA). Antibody levels measured with these methods correlated well (T-Ab: r = 0.72 to 0.88; M-Ab: r = 0.63 to 0.84; p less than 0.0001). However, when the results of the measured samples were classified as normal, slightly elevated and pathological, only 40-50% of the samples showed congruous results in all tests; 60-70% agreed in PHA and ELISA, whereas 80 to 90% corresponded in the two PHAs. RLA and ELISA gave more frequently positive results for T-Ab and negative results for M-Ab than the PHAs. Despite the lower sensitivity of the quantitative methods for M-Ab detection, they depicted more readily small changes after thyroxine treatment than the PHAs. We suggest that differences in autoantibody levels found with different methods may be due to autoantibody heterogeneity.

Autoantibodies↗

Laboratory workshop on the characterization of anti-platelet antibodies in immune thrombocytopenic purpura.

The aim of this laboratory workshop was to evaluate the state of knowledge concerning the demonstration of membrane glycoprotein specific anti-platelet antibodies. The main interest lay in investigating whether specific antibody detection offers possibilities to distinguish the chronic from the acute form of ITP. In five laboratories four different methods were applied to demonstrate such antibodies. These methods are briefly described and compared. In all, except two, of the 45 ITP samples anti-platelet antibodies could be detected by at least one participating laboratory, in 85% of the samples antibodies were found by two or more laboratories. For seven out of eight control samples no positive results were reported. The comparison of glycoprotein specific anti-platelet antibodies shows partly considerable differences which may be due to the different methods as well as the different antibodies used (monoclonal antibody against membrane glycoprotein and antihuman globulin sera). This laboratory workshop leads to the conclusion that by exchange of reagents and patient samples the different methods may be compared and evaluated. The results obtained allowed no further characterization of ITP. All participants agreed on the usefulness of further similar laboratory workshops.

Acute Disease↗

Biochemical evidence that equine leucocyte antigens W13, W22 and W23 are present on horse major histocompatibility complex class II molecules.

A number of horse alloantisera were characterized biochemically as being directed against MHC class I or class II antigens by immunoprecipitation of the corresponding antigens from lysates of biosynthetically radioactively labelled lymphocytes and determination of their molecular weights by SDS-PAGE and fluorography. Sera recognizing A2 and A3 specificities precipitated antigens of 44,000 Daltons molecular weight (class I heavy chain), whereas sera with specificities W13, W22 and W23 precipitated antigens corresponding to class II dimers (30,000 and 32,000 Daltons). Comparison with antigens precipitated from horse lymphocyte lysates using (cross-reacting) antibodies to human class I and class II MHC molecules confirmed the results obtained.

Animals↗

Low-energy He-Ne-laser irradiation of the bovine mammary gland.

The bovine mammary gland was used to examine the effects of low-energy laser irradiation. Laser irradiation with 25 mW on an area of 7.5 cm in diameter on the right front quarter lasted 30 minutes daily for five consecutive days. Six cows were used to assess the effects of this treatment on the healthy mammary gland. Subclinical mastitis was induced in twelve quarters of the same six cows with oyster glycogen and the same laser protocol was followed on the right front quarters. In both experiments the left hind quarter served as a control. Four cases of spontaneous subclinical mastitis were treated in the same way. Parameters measured included milk yield, somatic cell count, conductivity, Na/K-ratio in milk serum, and fat, protein and lactose concentrations in milk. The bovine mammary gland was chosen in view of its particular suitability for the assessment of changes in biosynthetic capacity and inflammation course. In several respects, mastitis may be compared to currently recommended indications. No evidence for any stimulation of the healthy mammary gland or therapeutic effects on mastitis by low-energy He-Ne-laser could be found.

Animals↗

[Assessment and course of 110 patients with mono-arthritis].

This is a follow up study of 110 patients referred to the hospital because of mono-arthritis of unknown etiology. Patients with mechanical synovitis and infectious arthritis have been excluded from this study initially. From a total of 110 patients (100%) a diagnosis could be made in 49 patients (44.6%), namely in 24 (21.8%) by the initial very thorough work up or by the repeated examinations during the follow up period in 25 patients (22.8%). In 61 patients (55.4%) the cause of the disease remained unknown despite extensive investigations and follow up controls for many years. Of these 61 cases three (2.7%) developed polyarthritis and six (5.5%) oligoarthritis still of unknown origin. The rest, namely 52 (47.2%) remained mono-arthritis and are called mono-arthritis of unknown origin ("Arthritis unbekannter Ursache"). 67% of these 52 patients with mono-arthritis of unknown origin went into complete remission after one year and 80% after two years. 13 patients (11.8%) of the 110 developed rheumatoid arthritis within one month up to three years. Arthroscopy was important in making some diagnosis initially. Twelve patients had relief of symptoms after arthroscopy, ten of the group with mono-arthritis of unknown origin. 19 patients claimed that the initiating factor was a trauma to the joint.

Arthritis↗

[Animal rights].

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Animal Welfare↗

[The cervical vertebral column of horses--a clinico-radiological study].

For various anamnestic reasons the cervical vertebral column of 78 horses was examined radiologically. Statistical comparisons showed that male "warmbloods" were more frequently affected than was expected. Our horses were older than comparable animals in the international literature. Independently of their history the radiologic diagnosis of "cervical spondylarthrosis" was established in 56 horses. Arthrosis and other conditions were clinically manifested by spinal ataxia (44 horses) or mechanical impairment of the neck's mobility (21 horses). 10 of the arthrotic patients had synovial cysts causing compression of the spinal cord. 79 percent of all dorsal intervertebral arthrotic joints were found in the caudal column (C6/7 to C7/Th1). With 38 percent, C6/7 was the most frequently affected joint. Clinical and radiological findings could be compared with patho-anatomic results in 29 horses. The correlation was satisfactory.

Aging↗

Age-related involution and terminal disorganization of the human thymus.

The terminal involution pattern of the human thymus was studied based on autopsy cases (both sexes, age range 63-91 years). Large sections through the entire thymic fat body were examined with the help of both conventional histological and immunohistochemical techniques. The findings demonstrate that thymic atrophy in old humans (a) goes far beyond the degree of involution observed in small rodents; (b) results in a system of thin, branching, in part interrupted, non-keratinizing epithelial plates containing no typical Hassall bodies; (c) concerns all components of the thymus except fat tissue which progressively replaces original thymic structures; and (d) involves various types of disorganization of individual lobules with T and B lymphocytes often located outside rather than within epithelial remnants. Effects of low-level radiation on this final regression of the human thymus are unknown.

Age Factors↗

Serological and genetic study of the ELA W21 specificity.

Investigations on the W21 specificity showed that this antigen is expressed on lymphocytes and platelets but not on erythrocytes. The molecule carrying the antigen W21 moves in the cell membrane independently from ELA locus A and B encoded antigens, as observed in 'lysostripping'. The W21 specificity occurs with very different gene frequencies in various breeds. In informative families it segregates together with defined gene products of the MHC region. The data suggest strongly that the W21 specificity belongs to the ELA system as a class I gene product, but is governed by a separate locus than the known locus A and locus B allelic series.

Absorption↗

Restriction fragment length polymorphisms of horse class II MHC genes observed using various human alpha- and beta-chain cDNA probes.

Genomic DNA isolated from 20 horses was digested with up to six restriction endonucleases and subjected to southern blot hybridization analysis using various human class II alpha- and beta-chain cDNA probes. A high degree of restriction fragment length polymorphism (RFLP) was found for the DQ alpha, DP beta, DQ beta and DR beta probes, about 20 polymorphic bands being detected for each. DR alpha showed 2-4 polymorphic bands, whereas no evidence for DP alpha-like genes was found. A number of correlations of RFLPs with individual alloantisera were apparent.

Animals↗