Killing of Plasmodium falciparum in vitro by nitric oxide derivatives.

We have investigated the in vitro susceptibility of the human malaria parasite Plasmodium falciparum to killing by nitric oxide and related molecules. A saturated solution of nitric oxide did not inhibit parasite growth, but two oxidation products of nitric oxide (nitrite and nitrate ions) were toxic to the parasite in millimolar concentrations. Nitrosothiol derivatives of cysteine and glutathione were found to be about a thousand times more active (50% growth inhibitory concentration, approximately 40 microM) than nitrite.     

Spontaneous recovery of the decreased expression in vitro of interleukin 2 receptors in rheumatoid arthritis.

Peripheral blood mononuclear cells (PBM) from 11 patients with rheumatoid arthritis (RA) stimulated with 0.13 and 0.25 microgram/ml phytohaemagglutinin (PHA) for 3 days showed a depressed expression of interleukin 2 receptor (IL-2R) when compared with 14 normal controls (P less than 0.01). At these two doses of PHA a depressed lymphocyte proliferative response was also observed (P less than 0.01). However the kinetics of the response of the RA group differed from those of the control group. Whereas by day 6 IL-2R expression and lymphocyte proliferation in the control group was decreased compared with day 3, responses of the RA cells were increased. Following stimulation with the higher dose of PHA (1 microgram/ml) the kinetics of lymphocyte proliferation and IL-2R expression were equivalent in control and RA cultures. These results demonstrate that the impaired IL-2R expression and lymphocyte proliferation observed with sub-optimally stimulated PBM from RA patients is spontaneously reversed during prolonged culture and is consistent with the hypothesis that there is a lack of available IL-2 in the early stages of culture.     

Lymphocyte infiltration in oesophageal carcinoma: lack of correlation with MHC antigens,ICAM-1, and tumour stage and grade.

Infiltration by T lymphocytes into oesophageal carcinomas was assessed immunohistochemically, total T lymphocyte numbers by staining for CD3 and activated T lymphocytes by staining for CD25. Five squamous carcinomas and seven adenocarcinomas, resected without neoadjuvant treatment, were studied. Computer aided quantitation showed that total numbers of tumour infiltrating CD3 positive cells were highly variable (range 48-1673 cells/mm2). They were located largely in the stromal (87.9-99.2%) rather than intratumoral regions. Up to 84% of tumour infiltrating T lymphocytes were CD25 positive, although the median figure was 33%. There was no correlation between T lymphocyte infiltration or activation and expression of class I and II histocompatibility antigens, intercellular adhesion molecule-1, tumour stage or grade. These results imply that the local inflammatory response in oesophageal carcinomas is deregulated, which may be a factor contributing to the aggressive nature of the tumours.     

Application of DNA arrays to toxicology.

DNA array technology makes it possible to rapidly genotype individuals or quantify the expression of thousands of genes on a single filter or glass slide, and holds enormous potential in toxicologic applications. This potential led to a U.S. Environmental Protection Agency-sponsored workshop titled "Application of Microarrays to Toxicology" on 7-8 January 1999 in Research Triangle Park, North Carolina. In addition to providing state-of-the-art information on the application of DNA or gene microarrays, the workshop catalyzed the formation of several collaborations, committees, and user's groups throughout the Research Triangle Park area and beyond. Potential application of microarrays to toxicologic research and risk assessment include genome-wide expression analyses to identify gene-expression networks and toxicant-specific signatures that can be used to define mode of action, for exposure assessment, and for environmental monitoring. Arrays may also prove useful for monitoring genetic variability and its relationship to toxicant susceptibility in human populations.     

Conservering van cosmetica en contactlensvloeistoffen

Conclusie De verscheidenheid aan conserveermiddelen die in cosmetica worden toegepast, is zeer groot. Het is wenselijk het gebruik van deze verbindingen zo beperkt mogelijk te houden in verband met ongewenste bijwerkingen voor de gebruikers. Een effectieve conservering van produkten, waarin micro-organismen goed kunnen groeien, is echter noodzakelijk. Deskundige microbiologische begeleiding bij de ontwikkeling en fabricage van cosmetische produkten is dan ook essentieel.

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Voordracht gehouden tijdens het symposium Conserveermiddelen op 13 november 1980 te Rotterdam.

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Dit artikel wordt gelijktijdig geplaatst in De Waren Chemicus.