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E Sommer

Publications and source records attributed to E Sommer.

At least 37 records · Page 2Linked to original sources
PubMed1992

New polymorphic HLA-DR epitopes recognized by three monoclonal antibodies produced against DR103 transfected L cells.

Production of monoclonal antibodies directed against polymorphic epitopes of HLA class II molecules using whole human cells as immunogen has often proved ineffective, because most of the antibodies produced are directed against non-MHC human cell surface molecules. One approach to overcome this problem is the use of transfected mouse L cells expressing a single HLA class II allele as immunogen. By immunizing C3H mice with DR103-transfected L cells, we obtained 3 mAb, OHA TM901, OHA TM902, and OHA TM903, that recognize different polymorphic epitopes of the HLA-DR molecule. The molecular specificities of the 3 mAb were determined on a large panel of B-lymphoblastoid cell lines (B-LCL), peripheral blood cells and HLA class II transfectants from the XIth International Histocompatibility Workshop. Interestingly, the 3 polymorphic mAb detect new HLA-DR epitopes shared by several specificities: OHA TM901 reacts with DR1 (DR101, DR103), DR9 (DR901) and DR10 (DR1001) molecules; OHA TM902 recognizes the same molecules but also DR8 (DR801, 802, 803); OHA TM903 reacts with all DR types except DR3 (DR301, 302), DR7 (DR701, 702) and DR52. Surprisingly, OHA TM901 reacts with DR9 transfectants and B-LCL but not with DR9 peripheral blood lymphocytes. Biochemical analyses indicate that the 3 mAb immunoprecipitate HLA-DR products and react in western blots with DR alpha/beta-dimer but not with free alpha- or beta-chains. This study shows that transfected L cells are very useful tools for the production and the fine characterization of mAb recognizing polymorphic epitopes of HLA class II molecules.

Animals↗
PubMed1990

[Measuring contrast sensitivity using visual acuity tests in retinal and optic nerve diseases].

The luminance contrast needed to discern various test types was measured with monochromatic and achromatic light to detect discrete functional deficiencies of the retina and optic nerve in cases of normal visual acuity. Landolt rings corresponding to visual acuity levels from 0.04 to 1.0 were used as test types. A significant increase in the necessary minimum contrast was detectable with blue test light on large Landolt rings in patients with diabetic retinopathy, ocular hypertension and glaucoma and with green or yellow test light on medium-sized and small Landolt rings in patients with central serous chorioidopathy and optic atrophy. The additional contrast needed to reach the maximum visual acuity amounts to 14-100% compared with normal visual acuity, depending on the color of the test light and the diagnosis. The amount of contrast needed is greatest in retinal diseases, and it is therefore possible to a certain extent to distinguish these from diseases of the optic nerve.

Humans↗
PubMed1989

[Immunologic phenomena in patients with proliferative retinopathy in diabetes mellitus type 1].

As a rule, in long-lasting diabetes type 1 there appear vascular complications in a form of proliferative retinopathy. While looking for the causes of fast vascular changes, the authors considered the possibility of immunological disorders. They started prospective examinations of patients with diabetes type 1 and proliferative retinopathy changes in the fundus of the eye. The authors evaluated the activity of angiogenic factors released by mononuclear cells isolated from peripheral blood of the patients examined. The authors found a significantly higher activity of these factors in patients with proliferative retinopathy in comparison with a control group of healthy persons and a group of patients with diabetes type 1 and simple retinopathy. The results obtained may indicate to immunological changes in the pathogenesis of proliferative retinopathy.

Adult↗
PubMed1988

[Nocardiosis of the lung].

A rare case of pulmonary nocardiosis is reported. The patient was a non-immunodeficient Vietnamese woman. The age of the patient was 31 years.

Adult↗
PubMed1986

A new HLA-D specificity associated with DR blank: D-BON.

Since 1980, a DR blank specificity undefined by serology but known to segregate in families linked to DQw1 has been recognized. We describe a Caucasoid family, BON... where 4 among 8 children are homozygous for such a specificity; their cells can be used as homozygous typing cells and the specificity defined is provisionally called D-BON. There is no known consanguinity in this family. The homozygous D-BON cells carry DR molecules as shown by their reactivity with monomorphic anti-DR monoclonal antibodies. In a random family material consisting of 210 haplotypes, the gene frequency of D-BON is between 1 and 2%, which corresponds to about 40% of the DR blank frequency. The D-BON specificity seems associated with DQw1 and also with B35 and C4B2.

Adult↗
PubMed1985

Platelet absorption on the test tray (PATT): a rapid method for the screening of HLA class II antibodies using the two-colour fluorescence method.

Several strategies have been proposed for the screening of alloantisera towards HLA class II antigens. Most often the absorption of the sera with platelets is required in order to remove their anti-HLA-A, B, C activity. We have developed a simple micromethod for platelet absorption of sera: platelet absorption on the test tray (PATT); 0.5 microliter of platelet suspension is incubated with 0.5 microliter of the serum to be absorbed in the same tray which is subsequently used for the microlymphocytotoxicity by the two-colour fluorescence method. This technique is proved to be almost as efficient as classical absorption procedures: out of 44 anti-HLA-A, B sera the T-cell activity is completely removed in 43 by a classical procedure as compared to 41 by PATT; only 8% discrepancies were found among 394 reactions. PATT was then used for anti-B lymphocyte screening in 419 anti-HLA-A, B sera; 4% of the sera remained cytotoxic towards T and B lymphocytes while 35% reacted only with B cells, several of them being DR specific. PATT can also be useful for T/B lymphocyte differential cross-matches before kidney transplantation. The method is now routinely used in our laboratory for anti-HLA class II antibody screening.

Absorption↗
PubMed1985

[Effect of intestinal circulation on the osmotic balance between the intestinal lumen and blood in awake rats].

Total electrolyte concentrations in portal vein and aortic blood of unanesthetized rats were measured continuously by means of ultrafiltrate conductometry. Portal flow rate and mesenteric venous pressure (pmes) could also be measured. The last could be raised to any desired level by a specially developed portal vein clamp. Intraduodenal injections of water (0.5 or 1% BW) were given in a first series of experiments with and without sham-attacking (activating) the animal for 10 s and in a second series with and without raising pmes. Portal flow rate dropped in both cases. But whereas activation led to a decrease in the concentration changes in the v. portae and in arteriovenous differences, a rise in pmes had the opposite effect. Comparison of the total free water change in the v. portae (Mpo) with the quantity of water given (MH2O) revealed that Mpo/MH2O dropped in both series of experiments, provided that pmes was not increased by much more than 2 mm Hg (portal flow did not decrease much under normal). The differing results were explained by taking into account the specificities of blood circulation in the gut wall. The experiments have shown that even transient obstruction of gut tissue perfusion can delay dissipation of concentration imbalance between the gut and parenteral space, thus having adverse effects on the gut cells.

Animals↗
PubMed1983

Studies on intestinal absorption by single-injection technique and continuous measurement of portal vein blood electrolyte concentration and hematocrit in the alert rat.

Whole blood and ultrafiltrate conductivity in the portal vein (as a measure of hematocrit and total electrolyte concentration, Cel, respectively) and arterial pressure of alert rats were measured continuously. Single intraduodenal injections of solutions iso- and hyperosmotic to blood (0.5 or 1 per cent of body weight) produced characteristic changes which were compared with those after the application of water. Whereas H2O and isosmotic passively absorbed substances (sorbose and urea) caused a very variable Cel drop, isosmotic actively absorbed nutrients elicited individually constant but interindividually different (glucose greater than alanine++ greater than arginine) changes due to solute coupled electrolyte free water transport. This was taken as evidence of variable paracellular shunt permeability playing a role in passive, but not in active absorption. The magnitude of Cel changes was related to absorption rate, which was confirmed by behaviour with hypertonic solutions, where osmotic activity in the gut was lost the sooner, the more rapid absorption rate was. Shunt permeability was temporarily blocked by arginine. Hct changes immediately after injections indicated fluid loss from portal vein blood, which could be evaluated in the case of mannitol. The thickness of the absorptive layer, obtained from latency of Cel change after urea, delivered values not exceeding 0,51 mm for the unstirred layer. The latencies after glucose and alanine were usually not much greater than after urea. Cel rise after hypertonic solutions had the same latency as Cel drop after water. Small arterial pressure changes after nutrient solutions, mostly absent after injections of water and NaCl, indicated circulatory effects originating in the gut in association with the former.

Alanine↗
PubMed1982

HLA-A, B, C, DR antigens, Bf, C4 and glyoxalase I (GLO) polymorphisms in French Basques with insulin-dependent diabetes mellitus (IDDM).

The Basques were previously shown to present a high frequency of HLA-B18 and BfF1, which are known to be associated with insulin dependent diabetes mellitus (IDDM). During the VIII International Histocompatibility Workshop, we studied HLA-A, B, C, DR; Bf, C4 and GLO.I polymorphisms in 51 unrelated French Basque IDDM patients and in 50 controls. Haplotypes were established by family studies in all controls and some patients. Two haplotypes were frequently found in the controls: HLA-A1, Bw57, BfS, C4 F1S, DR7 and HLA-Aw30, Cw5, B18, Bf F1, C4Fs degree, DR3. The first one was not found in the patients. All the components of the second haplotype had increased frequencies possibly as a consequence of linkage disequilibrium with HLA-DR3: a highly significant association between IDDM and HLA-DR3 was observed (90.2% vs 24.0%, relative risk (RR) = 29.1, P less than 10(-11)). The HLA-DR4 frequency was slightly increased (37.3% vs 16.0%), and HLA-DR2 was not found. The silent allele C4s degree was particularly associated with early diagnosed IDDM (86.7% in patients with age at onset under 20 years vs 57.1% in other patients, P less than 0.02). The high relative risk for HLA-DR3/DR4 heterozygous vs that of individuals, possibly HLA-DR3 homozygous, supported the hypothesis that two HLA-DR linked genetic factors could be involved in the inheritance of IDDM susceptibility.

Adult↗
PubMed1980

HLA-a, B typing in Basque and other Pyrenean populations.

Fourteen HLA-A and 18 HLA-B antigens were studied in three samples of Pyrenean populations: 198 unrelated individuals of a "Pays Basque" group; 212 non-Basque individuals from a valley in Bearn, l'Ouzom; and 73 non-Basque individuals from the neighboring valley of Bareges. The results in the Basque and the non-Basque people from l'Ouzom were comparable: the gene frequencies of HLA-A29, Aw19.2, B17 were increased and the haplotypes HLA-Aw19.2, B18; A29, B12; A2, B5; A1, B17 were found frequently with a striking linkage disequilibrium; HLA-B18 had an increased gene frequency in all these Pyrenean populations, while Bw35 was frequent in l'Ouzom and Bareges, but not among the Basques. The characteristics of Bareges were very different: the gene frequencies of HLA-A2, A11, B7 were increased while the frequency of HLA-B5 was low; the most characteristic haplotypes were HLA-A2, B12; A2, B18; A11, Bw35; A11, B27. It is interesting to note discrepancies between ethnic and HLA classification of the Basques and the non-Basque population of l'Ouzom. The HLA characteristics are quite different in the Hareges sample, more closely resembling those of Northern Europe.

Ethnicity↗
PubMed1979

[Urinary cytology in tumors of the urinary tract].

Views on the usefulness of urinary cytology and the best methodological technic differ widely. We perform the examination with spontaneously voided urine; after centrifugation, a smear of the sediment is Papanicolaou-stained. With this method 15 patients were found over a two-year period to have a tumor of the urinary tract or a positive urinary cytology. In 13 patients a tumor was diagnosed; of these 10 had a positive, 1 a questionable and 2 a false negative cytology. In 2 patients the cytology was false positive. Retrospective reexamination of the two false negative results revealed unequivocally malignant cells. One of the two false positive results was confirmed retrospectively and the second could not be checked. The sensitivity of the method was 84.6% and the specificity for unequivocally positive cytologies was 83.3%. Provided the examination is performed by an experienced cytologist, urinary cytology is a useful method which is suitable as a screening test in hematuria and for regular checks in high risk patients (e.g. with analgesic nephropathy).

False Negative Reactions↗