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Biomedical subjects

M Böttcher

Publications and source records attributed to M Böttcher.

At least 37 records · Page 2Linked to original sources

Early signs of cognitive deficits among human immunodeficiency virus-positive hemophiliacs.

A total of 181 human immunodeficiency virus (HIV)-seropositive hemophiliacs and 28 hemophilic controls were evaluated by psychometric tests and by electroencephalogram (EEG). Patients were classified from stages 1-6 according to the immunological criteria of the Walter Reed staging system. Statistical analysis of psychometric data showed an effect of the stage of the disease on test performances, indicating a decline in attention, accumulation of perceptual interferences, decline in visuoperceptual speed and visuomotor response speed and reduced verbal memory performance, especially in stage 6 patients. Comparison of performance levels with normative test data already revealed cognitive deficits in about 20-30% of the patients in stages 2-5. As regards verbal memory, especially learning and recognition of new verbal information were impaired. In contrast, there was no significant deficit for nonverbal memory processing. Compared with the controls, patients exhibited an increasing number of abnormal EEG findings in stages 2-6. As a conclusion, in the stages before acquired immunodeficiency syndrome (AIDS) develops, EEG findings as well as psychometric findings indicate central nervous system involvement of AIDS in about 20-30% of cases, whereas in full-blown AIDS there is a marked increase to 80%. Besides a more general deficit of attention and psychomotor speed as is seen in subcortical dementia, there is evidence for a particular verbal learning disorder, suggesting additional selective impairment of the brain.

AIDS Dementia Complex↗

[Selected factors influencing the in vitro maturation of oocytes of cattle].

Studies were conducted into hormonal additives to medium and culturing time and their effects on in vitro maturation of bovine oocytes. The best maturation results were ensured in vitro by substitution of TCM-199 with FSH, HCG, and 17 beta-oestradiol: The stage of fertilisation capability (telophase I or metaphase II) was reached by 86% of all oocytes (115 of 134). The rate of maturation was worse with significance in FSH-free medium (62% or 101 of 163), and the amount of degenerated oocytes was twice as high (18%). Maturation in hormone-substituted medium for 28 to 30 hours is recommended under the condition that immature oocytes were cultured from juvenile antral follicles (2--5 mm in diameter).

Animals↗

[The influence of follicular factors on the in vitro maturation of bovine oocytes].

Immature oocytes from antral follicles of cattle were tested for the effect of follicular factors on maturation. In vitro maturation was accomplished by use of follicular fluid from small (2--5 mm) and large (above 15 mm) follicles and by addition to the medium of a granulose factor (GF) which had been isolated from the surface of granulosa cells. The parent material, with 84% (72/86) of oocytes at the germinal vesicle stage (GV-S) at the beginning of culturing, could be rated immature. 46% of all oocytes (41/89) had reached telophase I or metaphase II (full maturation) after 24 hours of maturation in hormone-free control medium (TCM 199 + 10% of foetal calf serum). 36% of oocytes (53/84), on the other hand, stayed between GV breakdown (GVBD) and anaphase I (incipient maturation). Full maturation was reached by as little as 14%. GF and follicular fluid from small antral follicles were found to inhibit GVBD in the oocytes. 59% (36/61) or 48% (61/127) of oocytes were blocked at GV stage. Positive determination of maturation inhibiting action of the above follicular components may provide a chance for their target-oriented use in control of the maturation process. The pool of immature oocytes of the ovaries, under such circumstances, might be more systematically utilised for in vitro manipulations.

Animals↗

[The effect of cumulus oophorus on the fertilization in vitro of mature oocytes of cattle].

The effect of the cumulus oophorus on fertilisation was investigated by 478 in vitro maturated bovine oocytes. Culturing revealed that the amount of defects on the pellucid zone and in ooplasm of cumulus-free oocytes was higher than that in oocytes cultured in the cumulus-oocyte complex (38 percent or 77/203 versus eleven percent or 30/275). Insemination of the cumulus-oocyte complex (COC) seemed to increase the fertilisation capability of bovine oocytes (63 percent or 70/111), though its penetration rate was only 45 percent (111/245) and was thus below that of cumulus-free oocytes (55 percent or 69/126). Use of COC is recommended as basic material for in vitro maturation and fertilisation.

Animals↗

A first screening for hemocompatibility of a universal support for selective and specific hemoperfusion.

A modified filmadsorber is presented, intended to be used for selective and specific hemoperfusion. It consists of a spirally wound cellulose nitrate film, onto which--after chemical activation with sodium periodate--albumin is bound, stabilized, sterilized and activated with glutaraldehyde. Various bioactive ligands containing amino groups can be coupled to this support. A subsequent treatment with dimethylamino borane stabilizes the bonds between cellulose nitrate, albumin, glutaraldehyde and ligand. Columns in which a second layer of albumin is bound to the support as a model for a bioactive ligand were first screened for hemocompatibility using rabbits. Leukocyte, thrombocyte and hematocrit behaviour during hemoperfusion showed that hemocompatibility of the support was good.

Adsorption↗

[Scanning electron microscopy study of the peritoneum as a dialysis membrane--a morphological study on the etiology of sclerosing peritonitis].

Scanning electron microscopy investigations of the surface of rat peritoneum were performed after application of isotonic saline solution and peritoneal dialysis solutions with osmolalities of 375, 528, and 680 mosmol x kg-1 and intraabdominal stay periods of 15, 30, and 45 minutes. Severe morphological changes of the peritoneal surface were shown as clotting and atrophy of microvilli, detachment of surface cells from the basement layer, destruction of the basal lamina and appearance of rough-fibrous submembranous connective tissue, which was observed even after application of isotonic saline solution into the abdominal cavity. In conclusion, sclerosing peritonitis is caused by a fruitless inflammation reaction of the organism against the unphysiological function of the peritoneum as dialysis membrane forced upon peritoneal dialysis.

Animals↗

[Hemocompatibility testing in the rat model by noninvasive blood flow measurement using an arteriovenous shunt].

The flowing periods of blood through biomaterial shunts were measured by means of a noninvasive sensor with sufficient reliability. Falsifications of the measuring results by foreign influences as roller pumps, punctures, changes of the cross section, or the coupling of different materials were avoided extensively. The accomplishment of the test is possible routinely without a great display of apparatus.

Animals↗

[Extracorporeal blood circulation in the unanesthetized free-moving rabbit--an animal model for biocompatibility studies].

The rabbit is suitable as a basis model for the extracorporal circuit (ECC) in long-term test (20 days). A decrease of the leucocytes and platelets is established already in the blank test qualified by catheter material and pumping influence. This effect can be compensated by the rabbit in long-term test. The typical decrease of the leucocytes and platelets does not show any significant alteration during many test days independent of the number of tests which were carried out in one rabbit (blank test and hemoperfusion). A hemoperfusion across activated carbon--independent of the albumin coating--leads to a significant decrease of the leucocytes in comparison to the blank test. This rabbit model is well-suitable for biocompatibility investigations respectively also for effective investigations of detoxication techniques taken as a basis of our results.

Animals↗

[Problems of exposure to organic mercury compounds in pregnancy].

On account of oral intake of mercury by contaminated foodstuff (eggs eaten by pregnant women) due to non-observance of legal decisions increased mercury concentrations in the maternal and infantile blood, in the urine and hair of the mother, in the placenta, the amnion, the cord blood and the breast milk could be proved in comparison to non-exposed pregnant women. Clinical and laboratory-chemical parameters did not show any symptoms of an intoxication in mothers and children. Demands for observance of the legal decisions and avoidance of professional dealing are particularly important for pregnant women.

Female↗

[Experimental testing of the left-ventricular and biventricular assistant systems in dogs].

The left-ventricular (LVAD) and bi-ventricular assistant system (BVAD) were tested in dogs. Our hitherto existing experiences give information specially for the indication of LVAD and BVAD. The risk of a belated application of the LVAD exists in case of only a clinical control by pressure parameters for the degree of a cardiac insufficiency caused by coronary starvations. An aortic pressure of nearly 150/70 mm Hg could be reached by means BVAD on condition of heart fibrillation and a left-atrial pressure of 20 mm Hg. The aortic pressure and the left-atrial pressure decrease drastically after disconnection of the BVAD and these attain the initial values again very promptly after a new connection with the BVAD.

Animals↗