Immunosuppression with cis-Platinum (II) Diammino-dichloride: Effect on Antibody Plaque-Forming Spleen Cells

A new antitumor compound, cis-platinum (II) diamminodichloride, suppressed antibody plaque-forming cells in C(3)H mice when given in a single dose of 10 mg per kg of body weight within 2 days before or after sensitization.     

Selection of biomaterials for peripheral nerve regeneration using data from the nerve chamber model

Peripheral nerve regeneration has been studied in a variety of animal models. Of these, the nerve chamber model has clearly dominated. It has been used to generate a large base of data that, however, cannot be analyzed usefully due to lack of standardization of experimental conditions and assays. Lack of standardization of critical experimental parameters of the model has, however, greatly limited the opportunity to compare directly data from independent investigators; as a result, progress in understanding conditions for optimal nerve regeneration has been stunted. In this article, we provide an overview of the major experimental parameters that must be controlled in order to generate data from independent investigators that can be compared directly (normalized data). Such parameters include the gap length, animal species, and the identity of assays used to evaluate the product of the regenerative process. Use of the recently introduced concept of critical axon elongation, the gap length at which the probability of axonal outgrowth (reinnervation) across the gap is 50%, leads to generation of a normalized database that includes data from several independent investigators. Conclusions are drawn about the relative efficacy of the various biomaterials and devices employed. Nerve chamber configurations that had the highest regenerative activity were those in which the tube wall comprised collagen and certain synthetic biodegradable polymers rather than silicone, and was cell-permeable rather than protein-permeable. In addition, the following tube fillings showed very high regenerative activity: suspensions of Schwann cells; a solution either of acidic or basic fibroblast growth factor; insoluble ECM substrates rather than solutions or gels; polyamide filaments oriented along the tube axis; highly porous, insoluble analogs of the ECM with specific structure and controlled degradation rate.     

Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk

Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer.     

Comparative effects of two beta-blockers on cardiovascular reactivity and type A behavior in hypertensives

This study compared the effects of beta-blockers differing in degree of central nervous system penetration on Type A behavior and cardiovascular reactivity to mental stress. Forty-six male hypertensives were assigned randomly to receive either highly lipophilic and nonselective propranolol, hydrophilic and cardioselective atenolol, the diuretic hydrochlorothiazide, or placebo. Subjects were administered parallel forms of the Structured Interview (SI) and performed mental arithmetic and a cognitive task prior to and after 6 weeks of therapy. Results indicated that diuretic and placebo subjects (subsequently combined into a single control group) did not differ and that both beta-blockers reduced heart rate but not blood pressure reactivity to mental stress (p less than 0.02), an effect that was strongest during the mental arithmetic test. Analysis of SI components indicated a reduction only in explosive speech for beta-blockers versus controls (p less than 0.05). For global SI classifications, seven out of 12 subjects (58%) receiving propranolol, three of 12 (25%) receiving atenolol, and four of 22 control subjects (18%) became less Type A (p less than 0.05). These data do not replicate results of a prior study obtained with atenolol and suggest that only a subset of hypertensive individuals show reduced Type A behavior with propranolol. Central nervous system mechanisms may be important in producing these effects.     

Physical fitness of blind and sighted children

Summary Twenty-seven children (age 7–17 years) with varying degrees of blindness but with no other known disorder were assessed for physical fitness. Twenty-seven randomly selected children with normal eyesight were also assessed. Maximum oxygen uptake ( ) was measured directly during a progressive exercise test on a treadmill. There was a significant and substantial reduction in in totally blind children (mean ± standard deviation 35.0±7.5 ml · min^–1 · kg^–1) compared with normal children (45.9±6.6 ml · min^–1 · kg^–1). Partially sighted children had a significant but smaller reduction in . Fitness assessed by a step-test was significantly reduced in the visually impaired children, and skin-fold thickness was also significantly greater in totally blind children.The level of habitual physical activity for each child, as assessed by a questionnaire, correlated with (r=0.53,p<0.0001). Blind children were significantly less active than normal children, and the difference between mean for blind and normal children became non-significant when their different activity levels were taken into account. It is concluded that totally blind children are less fit than other children at least partly because of their lower level of habitual activity.     

Evaluation of formalin-inactivated Clostridium difficile vaccines administered by parenteral and mucosal routes of immunization in hamsters.

Clostridium difficile produces toxins that cause inflammation, necrosis, and fluid in the intestine and is the most important cause of nosocomial antibiotic-associated diarrhea and colitis. We evaluated C. difficile antigens as vaccines to protect against systemic and intestinal disease in a hamster model of clindamycin colitis. Formalin-inactivated culture filtrates from a highly toxigenic strain were administered by mucosal routes (intranasal, intragastric, and rectal) with cholera toxin as a mucosal adjuvant. A preparation of culture filtrate and killed whole cells was also tested rectally. The toxoid was also tested parenterally (subcutaneously and intraperitoneally) and by a combination of three intranasal immunizations followed by a combined intranasal-intraperitoneal boost. Serum antibodies against toxins A and B and whole-cell antigen were measured by enzyme-linked immunosorbent assay, neutralization of cytotoxic activity, and bacterial agglutination. The two rectal immunization regimens induced low antibody responses and protected only 20% of hamsters against death and 0% against diarrhea. The intragastric regimen induced high antibody responses but low protection, 40% against death and 0% against diarrhea. Hamsters immunized by the intranasal, intraperitoneal, and subcutaneous routes were 100% protected against death and partially protected (40, 40, and 20%, respectively) against diarrhea. Among the latter groups, intraperitoneally immunized animals had the highest serum anticytotoxic activity and the highest agglutinating antibody responses. Hamsters immunized intranasally and revaccinated intraperitoneally were 100% protected against both death and diarrhea. Protection against death and diarrhea correlated with antibody responses to all antigens tested. The results indicate that optimal protection against C. difficile disease can be achieved with combined parenteral and mucosal immunization.