Anticonvulsant-induced changes in tissue manganese, zinc, copper, and iron concentrations in Wistar rats

Human epileptics have been reported to have low blood manganese (Mn) concentrations in comparison to nonepileptics, an observation that is important because Mn deficiency can increase seizure susceptibility in experimental animals. Factors that have been suggested to contribute to the low blood Mn levels in epileptics include anticonvulsant use, seizure-induced tissue redistribution of Mn, and genetics; in the present study, the first of these possibilities was tested. Wistar rats were fed semipurified diets containing diphenylhydantoin ([DPH] 3 g/kg diet), phenobarbital ([PB] 2 g/kg diet), or primidone ([PRIM] 3 g/kg diet) for 7 weeks, at which time they were killed and tissues collected and analyzed for Mn, zinc (Zn), copper (Cu), and iron (Fe) concentrations. In comparison to pair-fed rats, DPH- and PRIM-fed rats had significantly elevated liver Mn concentrations, while Mn concentrations in blood, brain, heart, and kidney were unaffected by anticonvulsant exposure. Changes in the concentrations of Zn, Cu, and Fe in specific tissues were also found. Overall, these findings suggest that the anticonvulsants tested do not lead to significant derangements in the metabolism of Mn.     

Interference of herbal drinks with urinalysis for drugs of abuse

Recently there have been claims among drug users that some herbal drinks interfere with urinalysis for drugs of abuse and yield false positive results. Proof of such claims has yet to be shown. Screening for drugs of abuse is usually carried out using fluorescence polarization immunoassay (FPIA) or thin-layer chromatography (TLC). Fifty herbal samples which are considered among the most purchased herbs in the consumer market were used to investigate such claims. The drug groups that were tested for included amphetamines, opiates, barbiturates, cocaine metabolite, methadone, and their analogs. The herbs were analyzed at different concentrations (0.1, 1, 3, and 5 g/100 mL of distilled water) using TLC and FPIA to determine if any interfere with urinalysis for drugs of abuse and yield false positive results. For the FPIA test, the sample infusions were analyzed directly using the automated ADX analyzer (Abbott Laboratory). For TLC, infusions of the herbs were added to a solid-phase extraction column (pH 9.25), then extracted with a methylene chloride-isopropanol solvent system. At this pH, neutral, basic, and acidic drugs of abuse are extractable. The developed chromatographic plates were sprayed sequentially with several reagents. None of the herbs in the concentration ranges screened showed any interference with TLC or FPIA, indicating the invalidity of such claims.     

Combined laparoscopic and endoscopic approach in patients with cholelithiasis and choledocholithiasis

BACKGROUND: The Optimal management of common bile duct stones in patients undergoing laparoscopic cholecystectomy remains controversial. METHODS: A prospective study was conducted in 145 of the 481 patients who had a preoperative endoscopic retrograde cholangiogram before their laparoscopic cholecystectomy. RESULTS: Endoscopic retrograde cholangiogram was successful in 138 patients (95%), and common duct calculi were found in 72 (50%) of them. Endoscopic sphincterotomy with ductal clearance was achieved in 62 of 67 patients during a mean of 1.4 sessions (range, 1 to 5). Five (3.4%) patients had complications after endoscopic intervention, all of which resolved uneventfully . Fourteen patients underwent laparoscopic common duct exploration, five had failed endoscopic extraction, five had their common duct stones left intentionally for laparoscopic intervention, and, in addition, four of the seven patients who had a failed endoscopic retrograde cholangiogram had stones identified by intraoperative cholangiogram. Ten of these 14 patients underwent a successful laparoscopic common duct exploration. Laparoscopic cholecystectomy was successfully completed in 134 of the 145 patients, and none had major intraoperative or postoperative complications. The mean postoperative stay was 2.7 days for those patients who underwent a successful laparoscopic procedure. The overall mean number of admissions for completing the treatment was 2.3. CONCLUSIONS: Combined laparoscopic and endoscopic approach is a viable option for patients with gallstones and choledocholithiasis.     

Optimal versus maximal safety of the blood transfusion chain in The Netherlands; results of a conference. College for Blood Transfusion of the Dutch Red Cross

The distribution of major components of the basement membrane, such as type IV collagen, laminin, and heparan sulfate proteoglycan (HSPG), was investigated in the rat cochlear duct. Immunofluorescence demonstrated that type IV collagen, laminin and HSPG were distributed along capillaries in the cochlear duct, including the stria vascularis, spiral ligament, spiral prominence and spiral limbus. Additionally, type IV collagen, laminin and HSPG were found to be distributed from the basement membrane of Reissner's membrane to that of the spiral prominence in a linear pattern. The scala media was surrounded by these basement membrane components, demarcating endolymph from perilymph, along epithelial cells except at the stria vascularis. These findings suggest that type IV collagen, laminin and HSPG create the anatomical separation between endolymph and perilymph, thus indicating that they may be involved in the regulation of fluid transport between the endolymph and perilymph.     

Characterization of recombinant Saccharomyces cerevisiae manganese-containing superoxide dismutase and its H30A and K170R mutants expressed in Escherichia coli

All known Mn-containing superoxide dismutases (MnSODs) have a highly conserved histidine (His-30 in Escherichia coli FeSOD) in the active-site channel, and nearly all have an active-site arginine (Arg-170) that has been proposed to play a combined structural and functional role [Chan et al., Arch. Biochem. Biophys. 279, 195-201 (1990)]. In Saccharomyces cerevisiae MnSOD, the active-site arginine is replaced by a lysine. The S. cerevisiae MnSOD gene has been cloned and expressed in E. coli, and H30A and K170R site-specific mutants have been prepared. The purified recombinant native (RN) and mutant enzymes were compared to one another and to the native enzyme purified from S. cerevisiae (SC) in terms of activity, temperature stability, and sensitivity to 2,4,6-trinitrobenzenesulfonate (TNBS) and phenylglyoxal (PG). All enzymes had high specific activities (SC = 5000, RN = 5600, H30A = 4500, K170R = 4600) (U/mg, using the pyrogallol assay). SC, RN, and H30A were very stable at 75 degreesC (pH 8.0), with half-lives of 4.7, 2.8, and 2.7 h, respectively, while K170R had a much greater temperature lability, with a half-life of 0.36 h under these conditions. TNBS (0.5 mM, pH 9.0, 25 degreesC) rapidly inactivated SC, RN, and H30A, with half-lives of 3. 5, 5.1, and 5.5 min, respectively, but only slowly inactivated K170R, with a half-life of 101 min. PG (20 mM, pH 9.0, 25 degreesC) caused very slow inactivation of SC, RN, and H30A by biphasic kinetics, and each enzyme retained >/=25% activity after 3 h of modification. K170R, on the other hand, was completely inactivated by PG under these conditions by first-order kinetics, with a half-life of 7.0 min. The data suggest that His-30, a residue highly conserved in the active-site channel of MnSODs and FeSODs, does not play a crucial role in catalysis or stability. In addition, Lys-170, a residue that is almost always arginine in the numerous other MnSODs and FeSODs sequenced to date, can be replaced by arginine with no loss of catalytic activity, but K170R is less stable and Arg-170 in this mutant is more exposed than the corresponding arginine in other SODs. RN and SC showed some surprising differences. Thus, while the specific activities of RN and SC are very similar, SC is more stable to inactivation at 75 degreesC, and less susceptible to inactivation by phenylglyoxal, than RN. These data suggest that there may be slight differences in the tertiary structures of SC, the native enzyme expressed in S. cerevisiae, and RN, the recombinant native enzyme expressed in E. coli.     

Food preferences, eating patterns, and physical activity among adolescents: correlates of eating disorders symptoms

PURPOSE: Food preferences, eating patterns, and physical activity patterns were examined in a cohort of adolescent females and males participating in a longitudinal study of the developmental antecedents of eating disorders. METHODS: All adolescents (n = 1494) in grades seven through ten in an entire school district completed a survey about their dieting behaviors, eating, and exercise patterns. RESULTS: Principal components analysis showed similar factor structures for food preferences and eating patterns among males and females. Gender differences were present in physical activity patterns. Sports participation was correlated with healthy food preference and was a significant predictor of eating disorders symptoms. Junk food preference was marginally inversely related to eating disorders symptoms in females. Preference for other types of foods and reported intake of foods were not related to eating disorders symptoms. The percent of variance in risk score accounted for by dietary intake and physical activity patterns was small. CONCLUSIONS: Psychological and social/environmental variables may explain a larger proportion of the variance in eating disorders risk than the dietary and physical activity variables examined in this study. Implications for understanding the etiology and behavioral expression of eating disorders are discussed.     

Assessing the impact of continuous quality improvement on clinical practice: what it will take to accelerate progress

The literature on continuous quality improvement (CQI) has produced some evidence, based on nonrandomized studies, that its clinical application can improve outcomes of care while reducing costs. Its effectiveness is enhanced by a nucleus of physician involvement, individual practitioner feedback, and a supportive organizational culture. The few randomized studies, however, suggest no impact of CQI on clinical outcomes and no evidence to date of organization-wide improvement in clinical performance. Further, most studies address misuse issues and avoid examining overuse or underuse of services. The clinical application of CQI is more likely to have a pervasive impact when it takes place within a supportive regulatory and competitive environment, when it is aligned with financial incentives, and when it is under the direction of an organizational leadership that is committed to integrating all aspects of the work.     

Degradation of hyaluronic acid, poly- and monosaccharides, and model compounds by hypochlorite: evidence for radical intermediates and fragmentation

Degradation of hyaluronic acid by oxidants such as HO. and HOCl/CIO- is believed to be important in the progression of rheumatoid arthritis. While reaction of hyaluronic acid with HO. has been investigated extensively, reaction with HOCl/ClO- is less well defined. Thus, little is known about the site(s) of HOCl/ClO- attack, the intermediates formed, or the mechanism(s) of polymer degradation. In this study reaction of HOCl/ClO- with amides, sugars, polysaccharides, and hyaluronic acid has been monitored by UV-visible (220-340 nm) and EPR spectroscopy. UV-visible experiments have shown that HOCl/ClO- reacts preferentially with N-acetyl groups. This reaction is believed to give rise to transient chloramide (R-NCl-C(O)-R') species, which decompose rapidly to give radicals via either homolysis (to produce N. and Cl.) or heterolysis (one-electron reduction, to give N. and Cl.) of the N--C bond. The nature of the radicals formed has been investigated by EPR spin trapping. Reaction of HOCl/ClO- with hyaluronic acid, chondroitin sulphates A and C, N-acetyl sugars, and amides gave novel, carbon-centered, spin adducts, the formation of which is consistent with selective initial attack at the N-acetyl group. Thus, reaction with hyaluronic acid and chondroitin sulphate A, appears to be localized at the N-acetylglucosamine sugar rings. These carbon-centered radicals are suggested to arise from rapid rearrangement of initial nitrogen-centered radicals, formed from the N-acetyl chloramide, by reactions analogous to those observed with alkoxyl radicals. The detection of increasing yields of low-molecular-weight radical adducts from hyaluronic acid and chondroitin sulphate A with increasing HOCl/ClO-concentrations suggests that formation of the initial nitrogen-centered species on the N-acetylglucosamine rings, and the carbon-centered radicals derived from them, brings about polymer fragmentation.     

Physical activity in urban white, African-American, and Mexican-American women

PURPOSE AND METHODS: The purpose of this study was to analyze physical activity in a large, diverse sample of urban women (N = 521; X = 40.5 +/- 10.5 yr) relative to race/ethnicity, income, age, and education, using a sex-specific physical activity questionnaire. We also examined demographic and behavioral predictors of high levels (> or = 2000 kcal.wk-1) of leisure-time physical activity (LTPA; exercise, sports, recreational activities) in this population. RESULTS: The majority of women were sedentary (0-666 kcal.wk-1 in LTPA), and only 8% of African-American women (N = 6), 11% of Mexican-American women (N = 4), and 13% of white women (N = 55) participated in the level of physical activity recommended by the surgeon general (i.e., moderate to vigorous physical activity most days of the week for at least 30 min). Women of color, women over 40, and women without a college education had the lowest levels of participation in LTPA. Logistic regression analysis indicated that education was the only significant predictor of high LTPA in white women (P < 0.01) and marital status was the only significant predictor of high LTPA in minority women (P < 0.001). Age, body mass index (BMI; kg.m-2), income, self-rated health, alcohol intake, and smoking were not significant predictors of high LTPA for any of the women. Because the majority of adult women from this sample do not participate in adequate amounts of physical activity as recommended by the surgeon general, they may be at increased risk for hypokinetic diseases. CONCLUSIONS: These results indicate that public health efforts to increase physical activity in women should be focused on women of color, women over 40, and women without a college degree. More attention to predictors of physical activity that are specific to race or ethnicity may improve intervention program design and implementation.