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Biomedical subjects

M Richter

Publications and source records attributed to M Richter.

At least 397 records · Page 22Linked to original sources
PubMed1978

[Organochlorine insecticide residues in tobacco and tobacco products. 1. Analytical method].

An analysis method for quantitative serial estimation of organochlorine insecticide residues in tobacco is reported. This method is based on an hexane extraction followed by column chromatographic clean-up and preseparation as well as qualitative and quantitative gas chromatographic analysis. The following 16 substances are analyzed: HCB, alpha-HCH, lindane, heptachlor, aldrin, heptachlor epoxide, o,p'-DDE, p,p'-DDE, O,P'-TDE, p,p'-TDE, o,p'-DDT, dieldrin, endosulfan, beta-endosulfan and endosulfan sulfate. In a sample of 5 g of tobacco there can be detected: HCB, alpha-HCH, lindane, heptachlor, aldrin, heptachlor epoxide--o,oo1 ppm; o,p'-DDE, p,p'-DDE, dieldrin--o,oo3 ppm; o,p'-TDE, p,p'-TDE-- o,o1 ppm; o,p'-DDT, alpha-endosulfan, beta-endosulfan--o,o2 ppm; endosulfan sulfate--o,o3 ppm; p,p-DDT--o,o5 ppm.

Chromatography↗
PubMed1978

[Organochlorine insecticide residues in tobacco and tobacco products. 2. Residue levels in raw tobaccos used in the DDR].

The levels of insecticide residues in GDR and imported leaf tobaccos are reported. With our analysis method 16 chlorinated hydrocarbons can be analyzed. No DDT was found in tobaccos from the People's Republic of Corea. The mean DDT level of tobaccos from Hungary was lower than 0,1 ppm, the possibly value of the future tolerance. With few exceptions samples of other countries contained less than 1 ppm of the total DDT-group. Only a cigar tobacco from Paraguay showed a very high residue level of 7,20 ppm. Except this sample the residue values are to be attributed to the DDT persistence in soil and the relatively high intake by tobacco, since with the exception of few countries no DDT is anymore used with tobacco. The lindane concentration was very low in all tabaccos. In some tobaccos traces or only very small quantities of other organochlorine residues were detected.

Commerce↗
PubMed1977

Binding of 16alpha-gitoxin and its 16-acetate to human serum albumin.

The binding of semi-synthetic (16alpha-gitoxin and its 16-acetate) and naturally occurring cardioactive glycosides (digitoxin, ouabain) to human serum albumin was studied using equilibrium dialysis, ultracentrifugation and gel filtration. 16alpha-gitoxin was 75% bound and its 16-acetate 95%. The percentage binding of digitoxin and ouabain was in good agreement with values reported in literature.

Chromatography, Gel↗
PubMed1977

[Little epidemic caused by Salmonella panama (author's transl)].

Between 8. 1. 1976 and 10. 8. 1976 16 new or premature born children got a gastroenteritis due to salmonella panama. All these children were together in one pediatric ward of the hospital. Most of them came directly for the labour ward or from the newborn-ward. They had antibiotic therapy due to the indication of the mother or the child. It was impossible to fine the source of the salmonella infection, therefore, finally the ward was closed. After radical desinfection new patients came to the ward. Again they were infected with salmonella panama. Now it became clear that contaminated milk (Humanan-Heilnahrung) was the source of infections. Most papers mention a mild benign course of the infections. In contrary we could see severe conditions dependent on the pre-damage of the child or his reduced immunity. The minimal number of germs of dietic food products needs to be examinated.

Cross Infection↗
PubMed1976

Immunocompetent cells in patients with malignant disease. I. The lack of naturally occurring killer cell activity in the unfractionated circulating lymphocytes from patients with chronic lymphocytic leukemia (CLL).

The unfractionated, buffy coat cells of patients with chronic lymphocytic leukemia (CLL) were compared with their counterpart cells from normal volunteers for the capacity to lyse chromium-labeled xenogeneic target cells in vitro. Whereas killer cells were consistently detected in the circulation of normal individuals, no significant numbers of killer cells could be detected in the circulation of CLL patients. It is concluded that either these cells are not present in the circulation of CLL patients or that they are present in small numbers undetectable by this procedure. The possibility that killer cells in CLL patients are diluted by the much larger number of immunoincompetent cells has been ruled out.

Cytotoxicity Tests, Immunologic↗
PubMed1976

Naturally occurring immunosuppressive agents. II. The ability of cell-free liver extracts to modify the rejection of allogeneic skin grafts in the rabbit.

It has been demonstrated that cell-free extracts of pig, rabbit and human liver, but not of other parenchymal organs, contain a factor or factors capable of suppressing the proliferative responses of allogeneic and xenogeneic lymphoid cells stimulated with PHA, PWM, Con-A and allogeneic lymphocytes. Intravenous injection of the liver extract is capable of modifying significantly the skin allograft rejection reaction in normal adult outbred rabbits. Work is now in progress to isolate this factor and to determine its composition.

Animals↗
PubMed1976

Immunocompetent cells in man. IV. The inhibition of pokeweed mitogen-induced blastogenesis of normal human peripheral leukocytes by trypsin: a B-cell mitogen of mouse, but not of human, lymphocytes.

Normal human peripheral blood lymphocytes were tested for their blastogenic response in vitro to trypsin. Although it has been shown by other investigators that mouse B lymphocytes are stimulated trypsin to undergo blastogenesis, we have shown that human lymphocytes are not stimulated by trypsin. Paradoxically, trypsin inhibits the response of human lymphocytes to pokeweed mitogen, a B-cell stimulat, without significantly affecting the response of these cells to phytohemagglutinin, a T-cell stimulant. These results serve to underline the functional dissimilarity of mouse spleen cells and human circulating lymphocytes, at least with respect to their blastogenic responses to mitogenic agents.

Animals↗