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Biomedical subjects

G Desoye

Publications and source records attributed to G Desoye.

At least 73 records · Page 4Linked to original sources
PubMed1991

Interactions between insulin and insulin-like growth factor I in the pathogenesis of polycystic ovarian disease.

Concentrations of growth factors were examined in 28 patients with clinical and endocrinologic signs of polycystic ovarian disease (PCOD). Elevated levels of total insulin-like growth factor I (IGF-I) and decreased levels of the human growth hormone (HGH) were found. Studies of carbohydrate metabolism and of insulin receptors on erythrocytes indicated insulin resistance in all PCOD patients. Elevated insulin and IGF-I levels seem to play a pathogenetic role in PCOD by influencing the development and steroid production of ovarian follicles. Interactions between insulin and IGF-I could be shown at different levels. A positive correlation between elevated insulin and IGF-I concentrations was demonstrated in patients with different classes of gestational diabetes. Hyperinsulinemia seems to be the trigger mechanism and therefore the key to the pathogenetic loop of polycystic ovarian disease.

Adult↗
PubMed1991

Insulin and glucose do not affect the glycogen content in isolated and cultured trophoblast cells of human term placenta.

The influence of insulin and glucose on the glycogen content of isolated trophoblast cells was measured for the first time. The cells were obtained by tryptic digestion of villous tissue from term placentae of 15 healthy women, further purified on a Percoll gradient and enriched by employing a monoclonal anti HLA class-I antibody. The cells stained intensively with PKK1 and exhibited the structural and phenotypical characteristics of intermediate and syncytiotrophoblasts. The mean glycogen content of cells cultured in Dulbecco's Modified Eagle's Medium with 5.5 mM glucose was 17.7 +/- 3.2 micrograms/mg protein, remained constant from days 1-4, and was unaltered by higher glucose concentrations (17 and 28 mM) in the medium. Between 2-5 h after a medium change, the cells contained 50% more glycogen than at the time of replacement. Short term (0-5 h) as well as long term incubations (24 h) with both pathological (10(-8) M) and physiological (10(-9) M) concentrations of insulin had no effect, with respect to either the rate of increase in glycogen or the maximum level. We conclude that the glycogen content of isolated syncytiotrophoblasts in vitro is invariant to extracellular glucose concentrations and is not regulated by insulin. This suggests that cells other than syncytiotrophoblasts and their immediate precursors account for the reported alterations of glycogen content in normal human term placenta in vitro under hyperglycemic or hyperinsulinemic conditions.

Cells, Cultured↗
PubMed1990

Measurement of non-specific binding by parallel or consecutive incubation procedures in receptor homogenates following tissue disintegrations by sonification.

It was demonstrated with 125I-labeled insulin and homogenates of human placenta that the energy and duration of tissue disintegration by sonification markedly affected the extent and reproducibility of binding. If the non-specific binding was determined by consecutive incubation on identical samples, as was the total binding, the data obtained were more reproducible and closer to the affinity values and number of receptors that had been obtained on isolated trophoblast membranes when compared to experiments in which the non-specific binding was measured on different samples than for the total binding. On isolated membranes, the results were almost unaffected by the method of measuring non-specific binding. Therefore, we suggest that total and non-specific binding should be measured consecutively on identical samples if only small amounts of homogenized tissue are available.

Cell Membrane↗
PubMed1990

GZ 100, 101, 106, 107, 111, 112, 116, 121: a series of monoclonal antibodies against human trophoblast antigens.

The GZ100 series comprises a panel of monoclonal antibodies which seem to be specific for human trophoblast antigens (with the exception of GZ111, which reacts with a number of other tissues). The GZ antibodies show different reaction patterns with different trophoblast cell types. As a panel the GZ antibodies recognize all trophoblast populations (Table 2). Thus these antibodies provide a means to distinguish between trophoblast cells and maternal cells. GZ112 might be used to sort out HLA-class I positive trophoblast cells of the basal plate without blocking the HLA antigenic determinant, since GZ112 is not an anti HLA-class I antibody. At present the antigens detected by the GZ antibodies seem to be proteins, most of them with molecular weights between 50 kD and 80 kD. The function of these antigens is unclear and will be studied in future.

Animals↗
PubMed1990

[Diagnostic value of biochemical tumor markers in brain tumors. Review of the literature and own experience with serum analysis of sialic acid (NANA), carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE)].

In a review of the literature the current knowledge of the diagnostic significance of sialic acid (NANA), neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) in the detection and differentiation of brain tumors is demonstrated. The efficiency of some additional biochemical tumor markers is briefly described. In a total of 101 patients of our own 63 patients operated on intracranial expansive lesions and 38 patients with non-tumoral diseases of the central nervous system were examined for their serum concentrations of NANA, NSE and CEA with additional determination of total serum protein (TSP) and C-reactive protein (CRP) concentrations. 24 benign, 15 semibenign, 12 semimalign and 12 malign expansions were compared with each other and with the controls for their tumor marker concentrations. The criteria of the diagnostic reliability (sensitivity, specificity, positive and negative predictive value) were calculated for each single marker and the reliability of information for the combined used markers was evaluated. In summary the following results were found: The concentration of C-reactive protein corresponded significantly with the NANA-concentrations on the one hand and with the CEA-concentrations on the other hand (p less than 0.05). NANA: 1. The average concentration increased with increasing malignancy (no significance). 2. Patients who suffered from non-tumorous diseases of the central nervous system which coincided with brain tissue lesions had often extremely high values. 3. 4 of 10 healthy controls had NANA-levels above the reference value. 4. The sensitivity was 44%, the specificity 73%, the positive predictive value 17%, the negative predictive value 88% (patients with pathological CRP- or TSP-values excluded).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1989

[Which immunologic mechanisms facilitate a successful pregnancy].

Three possibilities are discussed for the immunological mechanisms which may be operative in establishing and maintaining a successful grafting of a semiallogenic embryo: (1) The lack of maternal allogenic recognition due to either the absence or a decreased alloantigenicity of paternal alloantigens (HLA). (2) The local suppression of maternal immune reactions against the embryo by hormonally induced decidual suppressor cells and by molecules released from the placenta. (3) The placenta may serve as an immunological barrier filtering potentially cytotoxic cells and molecules out of the maternal circulation before they reach the fetus.

Embryo, Mammalian↗
PubMed1989

[Expression of histocompatibility antigens in human pre-implantation embryos].

The expression of HLA antigens on polyploid human preimplantation embryos, obtained in an in vitro fertilization program, was investigated by indirect immunofluorescence test using a panel of well-defined monoclonal antibodies. Neither HLA class I antigens and beta 2-microglobulin, nor HLA class II molecules could be detected on blastomeres and the zona pellucida. It is supposed that the absence of HLA antigens on human preimplantation embryos may be one of the mechanisms important for the acceptance of the embryo by the immunocompetent mother.

Embryo Transfer↗
PubMed1988

Lack of HLA class I and class II antigens on human preimplantation embryos.

The expression of HLA Ag on polyploid early human embryonic stages, obtained in an in vitro fertilization and embryo transfer program, was investigated by indirect immunofluorescence tests using a panel of mAb. Neither HLA class I Ag, beta 2-microglobulin, nor HLA class II molecules could be detected on blastomers. The zona pellucida also lacked these Ag, but granulosa cells expressed HLA class I Ag, beta 2-microglobulin, and HLA class II Ag. These results make it likely that the absence of HLA Ag is one of the mechanisms involved in protecting the implanting embryo from rejection by the immunocompetent mother.

Antibodies, Monoclonal↗
PubMed1988

Error analysis in equilibrium dialysis: evaluation of adsorption phenomena.

Various sources of error in equilibrium dialysis may lead to inaccurate results of binding experiments: (i) the finite time of dialysis; (ii) the Donnan effects; (iii) the adsorption of ligand to the membrane; and (iv) release of contaminating material from dialysis casings. These errors were analyzed for a polynucleotide-oligopeptide model system with particular regard to adsorption phenomena and the underlying mechanisms. Adsorption data were treated according to Freundlich and Langmuir isotherms. The latter turned out to be more appropriate for the consideration of adsorption phenomena with respect to a minimum error propagation. Furthermore, it was shown that the degree of adsorption varies with ionic strength and temperature and could be interpreted in terms of polyelectrolyte theory. The kinetics of both adsorption and of the ligand distribution between the polymer and buffer compartments follow first order at the beginning of dialysis which is in line with a simple diffusion process. After 13-15 h data deviate from first order kinetics indicating an alteration in the transport mechanism. The effects of errors on binding parameters were determined and a detailed protocol for correction is presented allowing one to obtain binding data from equilibrium dialysis experiments with the required degree of accuracy. The fundamental principles and results for the system under investigation generally apply to all protein-ligand systems.

Adsorption↗
PubMed1987

Lack of expression of HLA [corrected] class I and class II molecules on the human oocyte.

The expression of histocompatibility leukocyte antigen (HLA) class I and class II antigens on human oocytes was investigated by the indirect immunofluorescence assay using well-defined monoclonal antibodies. Oocytes were obtained from an in vitro fertilization program or were studied on frozen sections from human ovaries. Neither HLA class I, beta 2-microglobulin, nor HLA class II molecules were detected on cultured oocytes or frozen sections. The zona pellucida also lacked these antigens, but granulosa cells expressed HLA class I molecules. Our results also indicate the presence of certain types of class II molecules on granulosa cells. The present experiments demonstrate that the human oocyte belongs to those few cell types in the human body which are devoid of both types of HLA molecules.

Antibodies, Monoclonal↗
PubMed1987

CEA plasma levels in patients with intracranial tumours.

210 patients harbouring an intracranial tumour were tested for CEA plasma levels. It could be shown that this investigation was neither a useful screening test for detecting brain neoplasms nor suitable for follow-up on operated brain tumours. However, with the CEA plasma investigation an additional preoperative test is available for distinguishing between primary and secondary brain tumours. The positive evidence is only 29%, but in case of a CEA plasma value above 5.0 ng/ml a metastasis is indicated with a probability of 91%.

Brain Neoplasms↗
PubMed1987

Correlation of hormones with lipid and lipoprotein levels during normal pregnancy and postpartum.

In a comprehensive study the concentrations of plasma lipids and lipo- and apolipoproteins were measured in 24 nonpregnant women (control) and longitudinally in 42 women throughout gestation and postpartum. The results were correlated with hCG, 17 beta-estradiol (E2), progesterone (PG), human placental lactogen (hPL), and insulin levels by time series analysis. Insulin concentrations were constant until week 25 and increased thereafter. Plasma E2, PG, and hPL as well as plasma lipid levels rose continuously during gestation. Apolipoproteins AI, AII, and B concentrations increased until weeks 25, 28, and 32, respectively, and remained constant until term. Low density lipoprotein cholesterol reached maximum levels at week 36. High density lipoprotein cholesterol exhibited a triphasic behavior, with maximum levels at week 25, a fall until week 32, and maintenance of the level until term. Time series analysis revealed positive correlations with E2, PG, and hPL. These results provide evidence that apoprotein concentrations undergo pronounced serial changes during gestation, which in part might be due to the effect of E2. Furthermore, the importance of hPL as a determinant of the plasma levels of total and free cholesterol, triglycerides, and phospholipids is now documented.

Adult↗
PubMed1986

Fluctuations of plasma lipoprotein-A concentrations during pregnancy and post partum.

The changes in plasma lipoprotein-a Lp-a concentrations during pregnancy were investigated. Out of 42 women with normal pregnancy, 22 reached Lp-a values greater than 10 mg/dL. Plasma levels of Lp-a in addition to total cholesterol, and apolipoprotein B were measured at 4 to 6-week intervals during pregnancy and post partum. The hormones hCG, human placenta lactogen, progesterone, estradiol, and insulin were measured concomitantly. The results can be summarized as follows: Plasma Lp-a concentrations rose steadily during the first trimester of pregnancy and reached a maximum in the middle of the second trimester. Maximal Lp-a values in the 19th week on average were 2.8 times higher as compared to the values of the eight week of pregnancy. Plasma Lp-a fell from the 19th week of pregnancy, reaching a basal value at the time of birth. This value remained virtually unchanged until 6 months post partum. Despite the fact that apolipoprotein-B and total cholesterol rose significantly, exhibiting pronounced maxima during the course of pregnancy, there was no overlap in the shape of their concentration curve with Lp-a. The rise in plasma Lp-a concentration did not correlate with any of the measured hormones at a given time interval. Time shifted analysis of the concentration curve revealed a correlation with hCG, however, with a lag phase of approximately 11 weeks. This study substantiates the independent metabolic control of Lp-a, as compared to plasma apolipoprotein-B and total cholesterol.

Arteriosclerosis↗