Detection of heat-labile Escherichia coli enterotoxin with the use of adrenal cells in tissue culture.

Cell-free culture filtrates of heat-labile enterotoxin-producing strains of Escherichia coli are capable of inducing morphological changes and steroidogenesis in monolayer cultures of adrenal cells. These tissue culture changes are simiar to those induced by cholera enterotoxin and cannot be effected by culture filtrates of other enterotoxigenic or enteropathogenic types of bacteria. The results of the tissue culture studies correlated well with those done in the standard intestinal-loop systems and suggest that this tissue culture system could be used to significantly aid epidemiological and molecular studies with heat-labile Escherichia coli enterotoxin.

Gap junction assembly and endocytosis correlated with patterns of growth in a cultured adrenocortical tumor cell (SW-13).

After seeding at subconfluent densities, human adrenocortical adenocarcinoma cells (SW-13) proliferate to form a typical epithelial monolayer upon the culture vessel substratum. Single cells of the confluent monolayer are spontaneously released into the medium, however, where they may remain isolated or reaggregate with other floating cells. In this study, we examined the growth patterns of these cells in culture and analyzed alterations of their most prominent intercellular contact specialization, the gap junction, as cellular relationship changed during growth and development of the cell culture. We report here details of gap junction assembly during cellular aggregation and correlate the apparent endocytosis of gap junctions with the spontaneous release of single cells from the monolayer into the medium.

Sulindac-induced aseptic meningitis.

A 22-year-old woman with systemic lupus erythematosus experienced generalized pruritus, shortness of breath, pleuritic chest pain, visual blurring, severe photophobia, a stiff neck, an occipital headache, and a temperature of 39.4 degrees C within one hour after taking sulindac (Clinoril). Findings from a CSF examination disclosed a notable elevation of protein and a polymorphonuclear pleocytosis. All symptoms disappeared within 24 hours. Inhibition of prostaglandin synthesis did not seem to be the mechanism of this adverse reaction, since the patient tolerated aspirin.

Therapy of Mycobacterium marinum infections. Use of tetracyclines vs rifampin.

We describe four patients with Mycobacterium marinum infections who did not respond to two- to six-week courses of therapy with tetracycline, minocycline, and doxycycline. All four patients had prompt responses to therapy with either rifampin alone (two patients) or rifampin in combination with ethambutol. Results of antimicrobial sensitivity tests may be helpful in guiding therapy. Rifampin may be the drug of choice for treatment of these infections.

Cephalosporin-associated colitis and Clostridium difficile.

A case of cephalosporin-associated colitis occurred in which a tissue-cultured morphologic-altering activity was demonstrated in the patient's feces during the active episode. Neutralization of the tissue culture activity by antiserum directed against a partially purified toxin of Clostridium difficile provided a more suggestive link between the colitis and this clostridial species.

Statistical evaluation of the role of Helicobacter pylori in stress gastritis: applications of splines and bootstrapping to the logistic model.

Stress gastritis is a serious problem in the intensive care unit population. The recent discovery of the causal nature of Helicobacter pylori (H. pylori) in the development of gastric ulcers led us to examine its relationship with stress gastritis. We investigated this relationship in 874 veterans admitted to intensive care units who were tested for the presence of H. pylori and followed for 6 weeks for the development of stress gastritis. We fit spline models to assess functional relationships and used the logistic model to determine the association between H. pylori and stress gastritis. The predictive ability of the model was assessed with receiver operating characteristic (ROC) curve analysis and validated with the bootstrapping technique. Increased anti-H. pylori immunoglobulin A concentrations were found to be an important predictor of stress gastritis independent of other known risk factors.

The efficacy of rifampin as adjunctive therapy in selected cases of staphylococcal endocarditis.

Three patients with bacterial endocarditis (one case due to Staphylococcus aureus and two to S epidermidis) failed to improve on standard therapeutic regimens which were judged adequate by in vitro testing for sensitivity. Rifampin was added to the regimen in each case and resulted in increased bactericidal activity in the serum, sterilization of the cardiac valves, and clinical cure. The apparent clinical success that was achieved suggests that further investigation of the effectiveness of therapy with rifampin in selected cases of staphylococcal endocarditis is warranted.

Infective endocarditis due to penicillin-tolerant Streptococcus bovis.

Two Streptococcus bovis isolates obtained from patients with endocarditis were found to be tolerant to penicillin and other cell wall active agents. By time-kill analysis, penicillin and streptomycin acted synergistically against these strains. The existence of tolerant S. bovis strains should be considered when initially choosing antibiotics for the treatment of serious S. bovis infections.

Adherence of Enterobacteriaceae to human buccal cells.

A preliminary examination has been made of the adherencae isolated from sputa. The radioadherence method was found to correlate well with the conventional light-microscope adherence technique. Saturation of buccal-cell binding sites with bacteria occurred when less than 10% of the buccal-cell surface was occupied. The adherence of Enterobacter aerogenes to buccal cells was impaired by the prior adherence of bacilli of either the same strain, or of a strain of Klebsiella pneumoniae.

Inhibition of beta-adrenergic binding by fungal metabolites.

Strains of Aspergillus flavus, Fusarium sp., Rhizopus sp. and Candida albicans all produced inhibitors of beta-adrenergic receptor binding; strains of Saccharomyces sp. and Schizosaccharomyces sp. did not. In tests with glutamic acid as the sole nutrient source, a Fusarium sp. produced four-fold larger amounts of inhibitor than the other fungi. The inhibitor from the Fusarium sp. was further purified by lyophilisation and sequential solvent extraction in chloroform, ethyl acetate and butanol; 60% of the original activity was recovered. The inhibitor had an estimated molecular size of 650 Da, and did not absorb light in the visible or ultraviolet range. When compared with a similar inhibitor from Escherichia coli, the Fusarium sp. inhibitor appeared to be a more potent inhibitor of beta-adrenergic and dopaminergic binding to mammalian cells.

Drug removal during continuous arteriovenous hemofiltration: theory and clinical observations.

We have discussed the basic principles of pharmacokinetics and convective solute removal in the context of each other. Clinical observations appear to follow the theoretical expectations. For practical purposes plasma and plasma water are not different. In the calculation of drug sieving, venous samples do not contribute enough to warrant their extra costs. We recommend that drug removal in hemofiltration be expressed by the sieving coefficient, UF/A. Drug sieving data in humans undergoing CAVH are tabulated. Recommendations for supplemental dosing are discussed which are applicable to any clinical setting.

Serum antibody to Escherichia coli heat-labile enterotoxin in cattle and swine.

Antibody titers to Escherichia coli heat-labile enterotoxin (LT) were measured in serum samples collected from mature cows, butcher pigs, mature sows and adult sheep, horses, dogs, cats, turkeys, and chickens. The frequency of LT antitoxin titers was greatest in sows (94%) and less in cows (38%). Titers were higher in swine than in cattle. There were no LT antitoxin titers in serums from sheep, horses, dogs, cats, turkeys, and chickens. It was concluded that LT-producing Escherichia coli are prevalent in the swine population, but much less so in cattle and the other species examined.

Tetracycline therapy for chronic Lyme disease.

Two hundred seventy-seven patients with chronic Lyme disease were treated with tetracycline for 1 to 11 months (mean, 4 months); the outcomes for these patients were generally good. Overall, 20% of the patients were cured; 70% of the patients' conditions improved, and treatment failed for 10% of the patients. Improvement frequently did not take place for several weeks; after 2 months of treatment, 33% of the patients' conditions were significantly improved (degree of improvement, 75%-100%), and after 3 months of treatment, 61% of the patients' conditions were significantly improved. Treatment outcomes for seronegative patients (20% of all patients) were similar to those for seropositive patients. Western immunoblotting showed reactions to one or more Borrelia burgdorferi-specific proteins for 65% of the patients for whom enzyme-linked immunosorbent assays were negative. Whereas age, sex, and prior erythema migrans were not correlated with better or worse treatment outcomes, a history of longer duration of symptoms or antibiotic treatment was associated with longer treatment times to achieve improvement and cure. These results support the use of longer courses of treatment in the management of patients with chronic Lyme disease. Controlled trials need to be conducted to validate these observations.

Alteration of tyrosine aminotransferase activity in hepatoma cells in tissue culture by amphotericin B.

Two clonal lines of rat hepatoma cells, in tissue culture, that have steroid-inducible tyrosine aminotransferase (TAT) activities were shown to have different responses to amphotericin B. One of the cell lines (HTC) was relatively resistant to the growth-inhibiting effects of amphotericin B and demonstrated an inhibition of only its steroid-inducible TAT activity when exposed to the antifungal agent. In contrast, not only was the other cell line (MHC) sensitive to amphotericin B during its growth, but uninduced and induced enzyme activities were affected. During the first few hours after the exposure of MHC cells to amphotericin B, both basal and dexamethasone-induced TAT activity were reduced; with continued exposure, enzyme activity increased over that of untreated cells and was superinduced in the presence of maximal, stimulating amounts of steroid. The mechanisms by which enzyme activity is induced by amphotericin B are probably different from those mediated by steroids.

Interactions of choleragenoid and GM1 ganglioside with enterotoxins of Vibrio cholerae and Escherichia coli in cultured adrenal cells.

The heat-labile enterotoxins of Vibrio cholerae and Escherichia coli induce morphologic changes and steroidogenesis in clonal lines of adrenal tumor cells in tissue culture; these effects are preventable by prior incubation of either toxin with GM1 ganglioside (galactosyl-N-acetylgalactosaminyl [sialosyl] lactosyl ceramide; GGnSLC) but are not preventable by prior incubation of adrenal cells with choleragenoid. Choleragenoid, however, is capable of interfering with the ability of GM1 ganglioside to neutralize the effects of either toxin. These results suggest that the GM1 ganglioside may not be the true receptor for the toxins on adrenal cells, but that it is acting as a pseudoreceptor. The ability of a subunit (A) of the cholera enterotoxin molecule to induce in adrenal cells morphologic changes and steroidogenesis similar to those effects inducible by the whole toxin indicates the possibility that separate receptor sites on these adrenal cells may exist for the binding and active fragments of the molecule.