Toxicologic evaluation of modified gum acacia: mutagenicity, acute and subchronic toxicity.

Modified gum acacia, produced from acacia gum by a process analogous to the production of modified food starch, was tested for mutagenicity in the microbial reverse mutation assay. The assay employed a wide range of dose levels, both with and without metabolic activation. Test results gave no indication that modified gum acacia possessed any mutagenic potential. The acute oral toxicity of modified gum acacia was determined in two studies employing Sprague-Dawley rats, and the LD50 values were found to be >2000 mg/kg. The primary dermal irritation potential of modified gum acacia was evaluated in rabbits by the Draize method. Test results indicated that modified gum acacia was slightly irritating by the Environmental Protection Agency (EPA) classification but not a primary irritant by Consumer Product Safety Commission (CPSC) guidelines. The subchronic toxicity of modified gum acacia was examined in Sprague-Dawley rats fed diets containing 0%, 1%, 2.5%, and 5% modified gum acacia for 13 weeks. No dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed. Results of these studies indicate that modified gum acacia does not possess mutagenic potential and that animals are not adversely affected by acute or subchronic exposure to modified gum acacia.     

Certifying examination performance and patient outcomes following acute myocardial infarction

OBJECTIVE: To establish whether successful certifying examination performances of doctors are associated with their patients' mortality and length of stay following acute myocardial infarction. DESIGN: Risk adjusted mortality and survivors' length of stay were compared for doctors who had satisfactorily completed training in internal medicine or cardiology and attempted the relevant examination. Specifically, the study investigated the joint effects of hospital location, availability of advanced cardiac care, doctors' specializations, certifying examination performances, year certification was first attempted and patient volume. SETTING AND PARTICIPANTS: Data on all acute myocardial infarctions in Pennsylvania for the calendar year 1993 were collected by the Pennsylvania Health Care Cost Containment Council. These data were combined with physician information from the database of the American Board of Internal Medicine. RESULTS: Holding all variables constant, successful examination performance (i.e. certification in internal medicine or cardiology) was associated with a 19% reduction in mortality. Decreased mortality was also correlated with treatment in hospitals located outwith either rural or urban settings and with management by a cardiologist. Shorter stays were not related to examination performance but were associated with treatment by high volume cardiologists who had recently finished training and who cared for their patients in hospitals located outwith rural or urban settings. CONCLUSIONS: The results of the study add to the evidence supporting the validity of the certifying examination and lend support to the concept that fund of knowledge is related to quality of practice.     

An investigation of the difficulty of computer-based case simulations

This study investigated the characteristics of computer-based case simulations (CCS) that may be associated with case difficulty. Difficulty was defined as the average rating by physicians of examinee performance on a nine-point scale or the passing rate on the cases. Two data sets were used, one from an administration of 18 cases, the other from an administration of 22 cases with 13 cases used on both occasions. Stepwise regression procedures were used separately for case properties and for analytic scoring of key variables to identify the best sets of predictors of case difficulty. Because of the small number of cases, regression results were evaluated for consistency across both data sets and both difficulty measures. For key variables, the best set of predictors included the number of different serious errors of commission, risk items, and benefit items. In general, cases were more difficult for higher values of these variables. For case variables, the only consistent variable was the length of the paragraph that provided patient history, with longer paragraphs associated with more difficult cases. Other variables were less consistent, but were often related to the structure of the simulation or the severity of the patient condition. Although the findings for case variables were limited, the analyses were very helpful in illuminating the interconnections among the variables within cases.     

Determinants of transstenotic gradients observed during angioplasty: An experimental model

Pressure gradient measurement across a stenosis is used during angiopiasty to aid catheter positioning and estimate dilatation efficacy. The angiopiasty catheter itself, however, further reduces lumen size, and therefore augments the transstenotic gradient. To more precisely define the catheter influence on gradient, we derived a theoretical expression relating the measured gradient with the angiopiasty catheter in situ to the “true” gradient; that is, the gradient in the absence of the angiopiasty catheter. We then tested this theoretical construct in a canine femoral artery angiopiasty model. Fifty-four measurements were performed using 23 separate, 3-mm-long, 40 to 70% stenoses. As predicted by the theoretic model, “true” gradient is compounded by the angiopiasty catheter principally as a function of the angiopiasty catheter diameter (Dc) and the stenosis diameter (Ds). The best-fit curve of data points relating “true” and compounded gradients to various Dc and Ds combinations can be expressed as: Measured GRADIENT = K × true gradient, where K = 0.25 (e)^4.47 (Dc÷Ds and e = 2.718. Thus, the transstenotic gradient measured at angiopiasty overestimates “true” resting gradient in a predictable manner, which is dependent on the ratio of Dc to Ds.     

Spatial abilities,sex differences and EEG functioning

The relationship of EEG asymmetry to spatial performance was studied for high and low spatial ability males and females. As in previous research for high spatial ability males relatively greater right hemispheric activity was associated with successful spatial performance. For low ability males, a group rarely studied, the opposite relationship was found. Both high and low ability females showed no consistent pattern of relationships.     

Frey's syndrome.

Frey's syndrome occurs after parotid gland surgery or injury to the parotid gland and is characterized by gustatory sweating and erythema of the face upon mastication. The syndrome occurs in 50 to 60 per cent of all patients undergoing parotid surgery but the symptoms are only distressing to about 10 per cent of patients undergoing parotidectomy. A case of Frey's syndrome is reported The patient obtained good relief of symptoms with scopolamine cream and atropine cream. Other methods of therapy are discussed along with their limitations. Noninvasive therapy with topical anticholinergic creams is effective and seems appropriate in the control of gustatory sweating.     

Sex differences in odor identification ability: a cross-cultural analysis

To ascertain the generality of a sex difference noted in odor identification ability, the University of Pennsylvania Smell Identification Test (UPSIT) was administered to four groups of subjects: Black Americans (n = 438), White Americans (n = 1559), Korean Americans (n = 106), and Native Japanese (n = 308). The women of all four groups outperformed the men to the same relative degree. The Korean American group performed better than the Black and White American groups, which, in turn, outperformed the Native Japanese. Analyses of the proportions of subjects correctly answering each of the test items revealed considerable similarity of relative item difficulty among the subject groups. Taken together, these data suggest that sex differences in odor identification ability are probably not due to ethnic or cultural factors, per se.     

Pulmonary mixed-function oxidation: stimulation by glucose and the effects of metabolic inhibitors

Substrate requirements for pulmonary mixed-function oxidation of p-nitroanisole to p-nitrophenol were evaluated using the isolated perfused rabbit lung and a lung microsomal fraction. Addition of glucose (5 mM) to the lung perfusate (Krebs bicarbonate buffer) increased the mean rate of p-nitroanisole oxidation by 25–55 per cent; addition of pyruvate (5 mM) or palmitate (0.5 mM) gave similar results. Sucrose (5 mM) had no effect. Antimycin A, KCN, oligomycin and bis-hexafluoroacetonyl acetone (an uncoupling agent) markedly depressed p-nitroanisole metabolism by the isolated lung. KCN also inhibited p-nitroanisole metabolism by lung microsomes, but antimycin A was without effect. These results indicate that pulmonary mixed-function oxidation requires substrate for intermediary metabolism as well as ATP, for maintenance of maximal rates. Glucose and mitochondrial substrates are equally effective in providing the energy requirements and the reducing potential for this reaction.