Streptococcus sanguis bacteremia and colorectal cancer: A case report

Streptococcus sanguis, usually considered a nonpathogen of the oral cavity, was isolated from blood cultures from a patient who was subsequently found to have a cecal adenocarcinoma. Further studies are needed to determine if Streptococcus sanguis infections have diagnostic implications similar to those of Streptococcus bovis. © 1995 Wiley-Liss, Inc.     

Generation of nitric oxide from organic nitrovasodilators during passage through the coronary vascular bed and its role in coronary vasodilation and nitrate tolerance

This study investigated the release of nitric oxide (NO) from glyceryl trinitrate (GTN) and SIN-1 in Langendorff rabbit hearts. Infusion of either GTN (10-40 microM) or SIN-1 (0.45-4.5 microM) into the coronary inflow tract resulted in a decrease in coronary perfusion pressure and NO release (oxyhemoglobin technique) into the coronary effluent. NO release from SIN-1 occurred spontaneously whereas passage through the coronary circulation, i.e. active metabolism, was required for NO release from GTN. Removal of the coronary endothelium and blockade of endothelial NO formation did not affect NO release from GTN and SIN-1. In GTN-tolerant hearts, there was a considerable inhibition of GTN- but not SIN-1-induced NO formation and coronary vasodilation. These data suggest (1) that metabolic NO release from GTN occurs during passage of the coronary circulation and is independent of the presence of endothelium, and (2) reduced NO release is a major cause of nitrate tolerance.     

Intraincisional antibiotic in addition to systemic antibiotic treatment fails to reduce wound infection rates in contaminated abdominal surgery

One hundred ninety patients with peritonitis at the time of abdominal surgery were allocated at random to systemic antibiotic treatment alone or systemic antibiotic treatment combined with topical application of antibiotics in the wound at the time of wound closure. The overall wound infection rate was 17 percent without significant difference between the two treatment groups (P>0.80).     

Inhibition of platelet aggregation following chronic in vivo treatment of rats with nicotine: prevention by simultaneous application of propranolol

Platelet aggregability is known to be enhanced and platelet-survival time shortened in smokers when compared with nonsmokers. Up to now it is unknown which of the substances in tobacco smoke are responsible for these effects. To evaluate a possible role of nicotine, rats were chronically treated with the alkaloid (10 mg/kg/day), continuously released from subcutaneously implanted osmotic minipumps. Surprisingly, after 8 weeks, platelet sensitivity toward the aggregating stimulus adenosine 5'-diphosphate (ADP) was markedly reduced. The mean ADP concentration required to induce half the maximum rate of aggregation (EC50) was 0.88 mumol/L in nicotine-treated animals, as compared with 0.67 mumol/L in controls (p less than 0.002). Platelet aggregability remained normal when the rats were treated simultaneously with nicotine and the beta blocker propranolol (3.5 mg/kg/day); for these animals, the mean EC50 for ADP was 0.73 mumol/L. These results are suggestive of a catecholamine-mediated action of nicotine. However, neither the basal levels of cAMP in platelet-rich plasma, nor the cAMP levels attained after stimulation of platelet adenylate cyclase with prostaglandin E1 (PGE1), were affected by 8 weeks of treatment with nicotine or nicotine plus propranolol. No effect on platelet aggregation was observed when the rats were treated with nicotine for only 2 weeks, or when nicotine or nicotine plus cotinine were added to platelet-rich plasma in vitro in concentrations equal to those attained in vivo after 8 weeks. Thus, prolonged application of nicotine in vivo caused an inhibition of ADP-induced rat platelet aggregation presumably mediated by beta-catecholaminergic stimulation of platelets.(ABSTRACT TRUNCATED AT 250 WORDS)     

The MTT-assay as a rapid test for cell proliferation and cell killing: application to human peripheral blood lymphocytes (PBL).

The possibility to use the colorimetric MTT assay for measuring proliferation and cell death of human peripheral blood lymphocytes (PBL) was studied. In a range from 100,000-800,000 cells/well a linear correlation between the optical signal (OD signal at 570 nm) and the cell number was found. It is necessary to incubate the cells with the MTT at least 2 hours. After stimulation by different PHA concentrations a very good correlation between [3H] thymidine incorporation and MTT assay was found. A comparison of daunomycin cytotoxicity, measurement by trypan blue exclusion and MTT assay, gave also a good correlation between both methods. It can be pronounced that the MTT assay is a suitable method to measure cell proliferation and cell death of human PBL. The assay is easy to handle, a large number of probes can be assayed in a relatively short time and no radioactivity is necessary. For the measurement of the colored product a common ELISA reader can be used.