Revised laboratory manual helps solve problems

This paper describes a project to design a laboratory manual which could be easily understood and used by both those who work in and those who utilize the laboratory in a large teaching hospital complex. Results indicated increased employee knowledge of laboratory policies and procedures, and an improved relationship between patient units and the laboratory.     

An Eikenella corrodens toxin detected by plaque toxin-neutralizing monoclonal antibodies

Bacterial plaque from the gingival region of teeth contains cytotoxic agents which lyse undifferentiated human HL60 cells. A small panel of monoclonal antibodies (MAbs) was found to abrogate much of this activity and to detect antigens in certain strains of Streptococcus mitis and Eikenella corrodens. The aim of this study was to determine whether these bacterial antigens might be involved in HL60 cells cytolysis. Saline extracts were obtained by homogenizing washed, stationary-phase cells in 65 mM NaCl with a tight-fitting Potter-Elvehjem homogenizer. The extracts of E. corrodens were toxic to HL60 cells, whereas similar extracts of S. mitis were nontoxic. Adding plaque toxin-neutralizing MAb 3hE5 blocked the toxic effect of E. corrodens extract S. mitis extracts contained a single, strongly reactive antigen of 140 kDa (s140K antigen) detected on Western blots (immunoblots) by three MAbs from the panel. Rabbit antibodies raised to this antigen excised from the gel (anti-s140K serum) detected larger antigens in addition to s140K. E. corrodens extracts contained a number of antigens detected by the MAbs. Immunoglobulin G (IgG) was purified from anti-s140K serum by passage through DE52 cellulose. A 100-fold excess (by weight) of the purified IgG to E. corrodens protein specifically cross-precipitated an 80-kDa antigen plus a nonantigenic 16-kDa protein, presumably attached noncovalently. The remaining supernatant fraction had no toxic activity. A similar ratio of control IgG (from nonimmunized rabbits) did not precipitate these proteins, and the supernatant fraction had the same activity as the extract not treated with IgG. The proteins of 80 and 16 kDa were also detected in the anti-s140K immunoprecipitate by rabbit IgG antibodies to E. corrodens whole cells. The 80-kDa antigen, alone or complexed with the 16-kDa protein, may be involved in mediating the toxic activity in E. corrodens and plaque extracts.     

Evaluation of the gastrotoxicity of anti-inflammatory drugs: contribution of general registries of digestive endoscopy

The evaluation of the rate of gastroduodenal toxicity of anti inflammatory drugs is a difficult problem. We tried to analyse that question by studying the general endoscopic registers of the Gastro-Enterologic department of the hospital. This retrospective study concerns 2,945 endoscopies performed during the year 1988 and 1992 randomly chosen among the last 5 years. 992 results show injuries suggestive of non steroidal anti inflammatory drugs (NSAID) toxicity, however only in 65 cases the potential role of an anti inflammatory drug is mentioned: 36 men and 29 women, mean age: 50.6 +/- 19.6 years. Concerning the drugs, only the pharmacological classes they belong to are mentioned except for Aspirin. Acetyl salicylate acid 7 cases, NSAIDS 36 and Steroids 22. In the drug group 63% of injuries are located to the stomach (ulcers 13%, gastritis 50%), 37% to the duodenum (19% ulcers, 18% duodenitis). Compared to the groups with the same kind of injuries, but without any mention of drugs, there are no statistical difference in the proportion of ulcers. Aging and sex are not influent in our results on the genesis of drug induced ulcers. These results must be discussed because a lot of datas are missing in the registers and so the number of patients taking drugs is probably underestimated. This means that unless a prospective study is held with someone enquiring for all the risk factors, the study of the general endoscopic registers is not a good way to estimate gastrointestinal damages due to drugs.     

Pressure diuresis and natriuresis in DOCA-salt mice

The increasing use of mice in renal and cardiovascular studies has necessitated adapting physiological methods used for rats to mice, which are far smaller in size. We have adapted measurements of continuous renal blood flow, pressure natriuresis and diuresis, and laser-Doppler cortical and medullary flow to 40 g mice with DOCA-salt hypertension. We demonstrated a rightward shift in the pressure-natriuresis-diuresis curve. We conclude that with current, commercially-available equipment, sophisticated renal physiology can be conducted in the mouse. These methods will be important to investigations of gene-targeted mice.     

Nutrition of the fetus and premature infant

Nutrition in the fetus and the premature infant is a rapidly changing field, not solely due to the acquisition of new knowledge but also because there have been major conceptual advances that have altered our approach to nutrition during early stages of development. This special report will highlight some of these conceptual advances in this area.