A case report of duplex gallbladder and review of the literature.

Gallbladder duplication is a rare congenital abnormality first described by Boyden in 1926. Pre-operative diagnosis is essential in identifying anatomical abnormalities in order to avoid biliary injuries at the time of surgery or performance of an incomplete operation. We present a case of a duplex gallbladder and review of the literature.

Non-invasive genetic identification of small mammal species using real-time polymerase chain reaction.

DNA identification of non-invasive samples is a potentially useful tool for monitoring small mammal species. Here we describe a novel method for identifying five small mammal species: wood mouse, bank vole, common shrew, pygmy shrew and water shrew. Species-specific real-time polymerase chain reaction primers were designed to amplify fragments of the mitochondrial cytochrome b gene from hair and scat samples. We also amplified nuclear DNA from scats, demonstrating their potential as a source of DNA for population genetic studies.

The nitrilase family of CN hydrolysing enzymes - a comparative study.

The enzymes nitrilase, cyanide dihydratase and cyanide hydratase are a group of closely related proteins. The proteins show significant similarities at the amino acid and protein structure level but the enzymes show many differences in catalytic capability. Nitrilases, while catalysing the hydration of nitrile to the corresponding acid, vary widely in substrate specificity. Cyanide dihydratase and cyanide hydratase use HCN as the only efficient substrate but produce acid and amide products, respectively. The similarities of all these enzymes at the amino acid level but the functional differences between them provide a rich source of material for the study of structure/function relationships in this biotechnologically important group of enzymes. This review provides an overview of current understanding of the genetics and biochemistry of this interesting group of enzymes.

Group practice strategies to manage pharmaceutical cost in an HMO network.

OBJECTIVE: To evaluate the prevalence of various pharmaceutical cost management strategies used by group practices within a managed care network and their relationship to drug costs among enrollees. STRATEGIES STUDIED: Care management (gatekeeping, practice profiling, practice guidelines, case management), techniques for maintaining clinic medication records, and policies regulating physician interaction with pharmaceutical sales representatives (PSRs). STUDY DESIGN: Cross-sectional survey of primary care group practice organizations (n = 103) affiliated with Blue Cross Blue Shield of Minnesota in early 1996. METHODS: Multivariate linear regression analysis was performed on corresponding claims data for members continuously enrolled in these practices from January 1 to December 31, 1995 (n = 76,387), using the patient as the unit of analysis. RESULTS: Substantial variation in strategy prevalence was observed; this variation was thought to influence pharmaceutical costs. Seventy-six percent of practices had medication lists in outpatient medical records, 53% had policies limiting pharmaceutical detailing, and 44% had patients assigned to primary care gatekeepers; however, only 10% used outpatient nurse case managers. Use of outpatient nurse case managers (P < .010), primary care physician gatekeeping (P < .002), policies to control pharmaceutical detailing (P < .001), and medication lists and outpatient charts (P < .001) was found to be independently associated with lower pharmaceutical expenditures. Significant colinearity was found between group size and the strategies studied. CONCLUSIONS: Significantly lower pharmaceutical costs per member per year were observed in the groups reporting primary care gatekeeping, outpatient medication records, outpatient case managers, and policies regarding physician interactions with PSRs.

Correlation and prediction of phenytoin protein binding using standard laboratory parameters in patients after renal transplantation.

Renal transplant recipients provide a unique model for protein-binding studies in that patients experience hypoalbuminemia and renal dysfunction, both of which alter protein binding. The purposes of this investigation were to model the relationship between serum creatinine, blood urea nitrogen (BUN), albumin, and the unbound fraction of phenytoin (FU, as a percentage) in patients who had undergone renal transplant, and to determine the value of these measurements in predicting FU. Blood from 29 patients was collected at various time points after establishment of graft function. Sera were spiked with phenytoin to a concentration of 15 mg/L, and total/unbound phenytoin concentrations were determined. Correlations between FU and the biochemical indices of serum creatinine, BUN, and albumin were determined using multiple regression. The algorithm with the highest correlation at all times after the transplant became the method to predict future FU. This algorithm was applied prospectively in 23 samples from 14 other patients with variable renal function after transplant. Samples were analyzed as above and the corresponding biochemical indices of serum creatinine, BUN, and albumin were used to calculate FU values. Accuracy of the predictions was evaluated using prediction-error analysis. The best relationship between FU and the measured biochemical indices incorporated serum creatinine and albumin [y = 24.3 + 0.6(serum creatinine) - 3.9(albumin)] and served as the method for FU prediction. Prediction-error analysis resulted in a bias of -5.1% and a precision of 5.7%. This method failed to estimate FU with sufficient accuracy to permit clinical utility. The predicted value underestimated the measured value, and some other variable(s) must be affecting the binding even though serum creatinine and albumin are within or approaching the reference range. Consequently, estimating FU in patients with a history of uremia and hypoalbuminemia, based on measures of serum creatinine and albumin alone, should not be used.

Use of office-based smoking cessation activities in family practices.

BACKGROUND: Smoking is the leading cause of morbidity and mortality in the United States. Recommendations for increasing physician effectiveness in smoking cessation through the use of office-based activities have been disseminated, but the extent of implementation is unknown. We describe the degree to which selected family practices in Nebraska have implemented 15 specific office-based activities. METHODS: We employed a cross-sectional integrated multimethod design. A research nurse observed a target physician and his or her staff during a 1-day visit in a random sample of 89 family practices. Data collection consisted of focused observation of the practice environment, key informant interviews, medical record reviews, and in-depth interviews with the physicians. RESULTS: The majority of the practices sampled had an office environment that restricted smoking, but few used visual cessation messages or information in the waiting room offering help and encouraging patients to quit. Most had educational materials that were supplied by pharmaceutical companies for promoting nicotine replacement systems. These materials were easily accessible in more than half of the practices. Smoking cessation activities were initiated and carried out by physicians with minimal use of their staff. Smoking status was documented in 51% of the medical records reviewed but seldom in a place readily accessible to the physician. All physicians were very aware of the importance of smoking cessation counseling, and most felt confident in their skills. CONCLUSIONS: Despite identification of patient smoking as a problem, most practices were not using office-based activities to enhance and support physician counseling. New perspectives for helping practices with this task need to be explored.

The role of breastfeeding in sudden infant death syndrome.

The objective of this article is to review the literature regarding the risk of sudden infant death syndrome (SIDS) in bottle-fed infants compared to those that are breastfed. A meta-analysis and qualitative literature review were performed. Cohort and case-control studies were included if they met a minimum SIDS definition and presented data allowing calculation of an odds ratio (OR). Twenty-three studies were included in the meta-analysis. The studies were heterogeneous, and a majority (14) were of "fair" or "poor" quality. Crude ORs from 19 individual studies favored breastfeeding as protective against SIDS. The combined analysis indicated that bottle-fed infants were twice as likely to die from SIDS (pooled OR = 2.11; 95% CI 1.66-2.68). The results of the analysis show that there is an association between bottle-feeding and SIDS, but this may be related to confounding variables.

Expression of the cyanide hydratase enzyme from Fusarium lateritium in Escherichia coli and identification of an essential cysteine residue.

The filamentous fungus Fusarium lateritium is cyanide tolerant, due partly to the induction of the enzyme cyanide hydratase in the presence of cyanide. This enzyme catalyses the hydration of cyanide to formamide. The expression in Escherichia coli of a cDNA clone encoding cyanide hydratase is described. The cDNA cloned was expressed as a transcriptional fusion in the expression vector pKK233-2 and a high level of activity of cyanide hydratase was detected in E. coli. Site-directed mutagenesis of the cys-163 residue inactivated the enzyme.

Beyond patient satisfaction. Broaden the scope of quality measurement by integrating the marketing view with other perspectives.

The patient satisfaction perspective has dominated recent marketing efforts to measure and understand health care quality. The authors propose a broader health care quality model that includes medical outcomes, access to health care services, and personnel dimensions along with patient satisfaction concerns as the foci of quality measurement. The model also encompasses important contextual factors that clearly affect the level of health care quality.

Purification and properties of cyanide hydratase from Fusarium lateritium and analysis of the corresponding chy1 gene.

The filamentous fungus Fusarium lateritium is cyanide tolerant, due, at least in part, to the induction by cyanide of the enzyme formamide hydrolyase (EC 4.2.1.66). This enzyme, more commonly known as cyanide hydratase, catalyses the hydration of cyanide to formamide. The enzyme was purified from F. lateritium and showed a subunit molecular mass of 43 kDa (as judged by SDS-PAGE), while the native protein appeared to form aggregates of up to 1217 kDa (as judged by gel-filtration and non-denaturing PAGE). mRNA samples from cultures grown with and without cyanide were in vitro translated and immunoprecipitated. This demonstrated that, in this species, the gene encoding the enzyme designated chy1, is cyanide inducible. Differential screening was used to isolate a cyanide hydratase cDNA clone which was subsequently used to obtain the corresponding genomic clone. A fragment of the cDNA clone encoding all but the first seven amino acids of the protein was expressed in E. coli using the expression vector pGEX-2T. Features of F. lateritium cyanide hydratase together with an analysis of the nucleotide sequence encoding this enzyme are presented.

Hydrogen exchange kinetics and the mechanism of reaction B of yeast tryptophan synthase.

It has been shown that yeast tryptophan synthase (L-serine hydro-lyase (adding indoleglycerol-phosphate) EC 4.2.1.20) catalyses tritium exchange reactions between protons on the alpha-carbon of L-serine of L-tryptophan, and water. The absolute rates of these reactions and indole-serine condensation (reaction B), all of which are pyridoxal phosphate-dependent, were measured. L-Serine exchange was resolved into two components, a high-affinity, slow, Michaelian reaction (KmS,H = 0.06 mM, kcats,H 3 X 10(-3) s-1) and a faster reaction (kcat greater than 2.5 S-1) which was not saturated even at 100 mM L-serine. Hydrogen exchange by tryptophan was a Michaelian process (KmT,H = 2.9 mM; kcatT,H = 0.6 s-1). Indole did not inhibit either exchange reaction. A plausible explanation of the results, that reaction B has a ping-pong mechanism with serine as first substrate and water and L-tryptophan as first and second products, respectively, was inadequate because of the observations that L-tryptophan is as first and second products, respectively, was inadequate because of the observations that L-tryptophan is synthesised with less than 1 mol of exchanged proton per mol amino acid, and that the ratio kcat/Km for serine changes between enzyme reactions. A branched modification with two enzyme-serine complexes, only one of which will exchange protons with water, will fit all the results.

Molecular cloning of genes involved in purine biosynthetic and salvage pathways of Salmonella typhimurium.

Genes have been cloned from Salmonella typhimurium which when present on the multicopy plasmid pBR322 in the E. coli strain NT31 confer a Gua+ phenotype on this strain. NT31 is a purE gpt double mutant and it was expected that a Gua+ phenotype could be conferred on it by the cloning of either gpt or purE. It was, however found that in addition to these two loci the molecular cloning of another gene, which has been identified as hpt, in pBR322 confers a Gua+ phenotype on NT31. This result is explained by the overproduction of the hpt gene product, hypoxanthine phosphoribosyl transferase, which compensates for the lack of the gpt product guanine-xanthine phosphoribosyl transferase. Restriction analysis of the three loci, gpt, hpt and purE is also presented.

Purification and properties of tryptophan synthase from baker's yeast (Saccharomyces cerevisiae).

Tryptophan synthase was purified from baker's yeast. The purified enzyme exhibited one band on polyacrylamide-gel electrophoresis, had no detectable N-terminal amino acid and C-terminal alanine. The amino acid composition was close to that predicted by recent studies on the DNA sequence of the structural gene for the enzyme. Kinetic parameters for the following three activities were measured: indole-serine condensation, indolylglycerol phosphate lyase and the overall reaction of serine with 1-(indol-3-yl)glycerol 3-phosphate. The Km for indole was much lower than suggested by previous investigations, and the value of 11 microM was measured by a fluorimetric assay.

Glutamate receptor binding in insects and mammals.

High affinity stereospecific binding sites for L-glutamate have been reported in several regions of mammalian brain. The binding sites in the hippocampus and cerebellum have been studied more extensively than binding in other brain regions. The hippocampal and cerebellar binding sites show similar properties with respect to their pharmacology and their independence of Na+. There is evidence, particularly good in the case of hippocampus, of mechanisms that may regulate the availability of the binding sites in both brain areas. Some progress has been made with the isolation of the hippocampal binding site but the protein has not been extensively characterised. In the case of insect muscle, high-affinity stereospecific binding of L-glutamate to whole membrane preparations, to detergent-solubilised membranes and to isolated proteolipids has been reported. Much greater variability in the binding characteristics is seen than is the case with the mammalian brain preparations. Preliminary experiments suggest that at least four distinct binding sites may be present on insect muscle. The complete characterisation of glutamate binding sites is at present precluded by a lack of potent agonists and antagonists. However, recent advances in the pharmacological classification of receptor sites for the excitatory amino acids in mammalian brain could provide sufficient information to permit the identification of the binding sites as synaptic receptors. Invertebrate toxins whose site of action is the insect neuromuscular junction may well prove to be useful tools with which to isolate and characterise the synaptic receptor proteins.