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Biomedical subjects

V Knobloch

Publications and source records attributed to V Knobloch.

At least 19 recordsLinked to original sources
PubMed1997

[Effectiveness of anesthetic gas scavengers fulfilling EN 740 requirements with reference to equipment leakage and fresh gas flow].

PURPOSE: During inhalation anaesthesia, contaminations of the working environment be anaesthetic volatiles and nitrous oxide occur. The amount of leaking gases is influenced by leakages of the anaesthetic ventilator, by fresh-gas flows and by the effectivity of the scavenging system. Since 1st January 1996 new ventilators have to be equipped with scavenging devices according to the European standard EN 740. We measured the effectivity of this system with anaesthetic ventilators of a type that is now superseded (mean leakage rate 100 ml/min) and recent devices (mean leakage rate 5 ml/min) using high and low fresh-gas flows. MATERIAL AND METHODS: The anaesthetic ventilators were placed in a non-air-conditioned area. A test lung was ventilated with gas flows of 1 l/min, 3 l/min and 6 l/min (concentrations of nitrous oxide 70%, Enflurane 1%). The ventilation time in each case was 1 h. The minute volume was set to 8 l/min. At 2-minute intervals the concentrations of nitrous oxide and enflurane were measured by a multigas monitor Brüel & Kjaer 1302. The experiments were carried out with an old scavenging device according to DIN 13260 and a new device according to EN 740. RESULTS: Using the scavenging device according to DIN 13260, the concentrations of the pollutant gases were significantly dependent on the fresh-gas flows. No differences were found when using old or new anaesthetic ventilators. Medians of nitrous oxide (n2o) and Enflurane (e): 6 l/min: (n2o) 204 ppm (e) 4.3 ppm 3 l/min: (n2o) 115 ppm (e) 2.1 ppm 1 l/min: (n2o) 61 ppm (e) 0.97 ppm. Scavenging devices according to EN 740 significantly reduced the amount of emitted pollutants. No dependency on fresh-gas flows could be detected. 6 l/min: (n2o) 11.25 ppm (e) 0.05 ppm 3 l/min: (n2o) 10.12 ppm (e) 0.0 ppm 1 l/min: (n2o) 9.5 ppm (e) 0.0 ppm. CONCLUSIONS: The formerly reported dependence of the room air concentrations of anaesthetic volatiles and nitrous oxide from the fresh gas flow are caused by the spillage of pollutants through scavenging devices according to DIN 13260. The use of systems according to EN 740 is not only useful in new devices but must also be recommended for superseded models of anaesthetic ventilators.

Air Pollutants, Occupational↗
PubMed1991

[Phagocytosis in pregnancy].

The authors assessed the influence of pregnancy on the phagocytic activity by the fungus test in 30 women during the first third of pregnancy and in 30 women during the third trimester of pregnancy. The control group was formed by 30 non-pregnant women. It was revealed that the capacity of phagocytosis is preserved in all phagocytizing cells, their phagocytic activity declines, however, significantly during normal pregnancy. This may be due to a hitherto unknown suppressively acting factor or to exhaustion of the phagocytic activity of leucocytes due to an excess of immune complexes in serum of pregnant women.

Adolescent↗
PubMed1989

[Circulating antitrophoblast antibodies in normal pregnancy and in EPH gestosis].

Antitrophoblastic antibodies were assessed by the bond with the antigen of syncytiotrophoblastic membranes according to Davies (ELISA system) in 17 nulligravidae, in 33 men and 70 pregnant women. The pregnancy was normal in 27 women in the Ist and in 32 in the IIIrd trimester, 11 women had signs of EPH gestosis. The incidence of antitrophoblastic antibodies rises significantly with the period of gestation, in women with toxaemia the values are reduced as compared with the group in the third trimester. The authors did not find a relationship between the values of these antibodies and the concurrently assessed level of immunoglobulin IgG, IgA and IgM. Possibilities of the development of toxic immunocomplexes during EPH toxaemia are discussed.

Adolescent↗
PubMed1988

The development of immunological relationship between mother and fetus under physiological and pathological conditions.

On the basis of results of our research and review of literature, the complex of immuno logical influences, operating during the development of the human fetus, were evaluated. It is obvious that during the early stages of pregnancy the conceptus is protected by non-specific mechanisms, i.e. hormonally (HCG, progesterone) and by certain properties of the trophoblast (barrier function, immunologically inert surface). Specific immunological tolerance is formed by gradual penetration of trophoblast particles and later by penetration of fetal blood cells into maternal circulation. Thus a specific suppression of maternal T lymphocytes against fetal antigens develops, other immunological functions being intact. - Following a strong antigenic stimulus (e.g. Rh-D), isoimmunization of the mother and serious risk for the fetus occur. Immunological causes of abortion could not be unequivocally proved in recurrent abortions. The explanation of the origin of EPH-gestosis on the basis of toxic action of immunocomplexes is highly probable, however the laboratory and experimental proof is still lacking.

Abortion, Habitual↗
PubMed1979

Pregnancy-induced morphologic changes in lymphocytes; an experimental study on materno-fetal tolerance in the rat.

Morphological changes in lymphocyte nucleoli were examined in the course of pregnancy in rats. Small amounts of lymphocytes became activated, most of them producing micronucleoli. These findings show the same changes as found in the course of pregnancy in women. Subcutaneous administration of human placental eluate to non-pregnant rats induced a low degree of activation and high micronucleoli formation, dependent on the dose of placental antigen. Repeated administration of increasing doses of placental eluate revealed almost the same morphological changes in lymphocyte nucleoli as seen in normal pregnancy. This is considered an experimental verification that the morphological changes in lymphocyte nucleoli during pregnancy are due to permanent and gradually increasing doses of foreign antigen.

Animals↗
PubMed1976

Feto-maternal relationship in normal pregnancy in mixed lymphocyte cultures.

In eight wife-husband pairs during the whole pregnancy the reactivity of lymphocytes to PHA, to lymphocytes of unrelated donor and to lymphocytes of husband was studied. No statistically significant differences were found in reactivity of wife's and husband's lymphocytes. In eleven women at delivery a statistically significant decline of MLC reaction to lymphocytes of own and unrelated newborn was found, while the reactivity to PHA and to lymphocytes of unrelated adult donor remained unchanged. Similarly, the lymphocytes of eleven newborn infants reacted statistical significantly less to lymphocytes of own mother and unrelated mother, while the reaction to PHA and to lymphocytes of unrelated donor was well expressed.

Cells, Cultured↗