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At least 1,351 records · Page 75Linked to original sources
PubMed2000

Defining the role of laparoscopic-assisted sigmoid colectomy for diverticulitis.

PURPOSE: The purpose of this study was to evaluate the safety and efficacy of laparoscopic-assisted sigmoid colectomy for the treatment of diverticulitis. METHODS: The Norfolk Surgical Group Laparoscopic Surgery Registry identified all patients undergoing laparoscopic colon and rectal surgery. Retrospective chart review was performed for all patients undergoing elective sigmoid resection for a final diagnosis of diverticulitis and minimum follow-up of 12 months. Demographic data, indications for surgery, operative data, conversion rate, reason for conversion, complications, postoperative course (days to flatus and regular diet), and length of stay were identified. A telephone survey determined the incidence of recurrent diverticulitis. Statistical analysis was performed to evaluate the frequency of conversion over time, to determine risk factors for conversion, and to compare the laparoscopic-assisted and conversion groups with regard to postoperative days to flatus, regular diet, and discharge. RESULTS: From June 1992 to September 1997, elective laparoscopic-assisted sigmoid colectomy was attempted in 69 patients. Uncomplicated recurrent diverticulitis was the most common indication for surgery, occurring in 51 of 69 patients (75 percent). No deaths occurred. Complications were identified in seven patients (10.1 percent) including one wound infection and one incarcerated port-site hernia with small bowel obstruction. There were no anastomotic leaks or major septic complications. Conversion to laparotomy occurred in 18 of 69 patients (26 percent). Uncomplicated, recurrent diverticulitis was associated with conversion in 7 of 51 patients (14 percent), whereas complicated diverticulitis required conversion in 11 of 18 patients (61 percent). Logistic regression identified fistula and abscess as predictors of conversion (P = 0.0009). Comparison of the laparoscopic-assisted sigmoid colectomy group with the conversion group revealed that postoperative days to regular diet were 3.5 and 5.2 (P = 0.0004), respectively, and lengths of stay were 4.2 and 6.4 days (P < 0.0001), respectively. No difference was noted with regard to operative time or postoperative complications. Median follow-up was 48 (range, 13-76) months, and a single recurrence of diverticulitis has been identified. CONCLUSIONS: Laparoscopic-assisted sigmoid colectomy for diverticulitis can be safely performed. Conversion appears to be associated with complicated diverticulitis (fistula or abscess), which may be better approached by laparotomy. Short-term follow-up indicates that recurrence is rare and suggests that laparoscopic-assisted sigmoid colectomy achieves adequate resection. Laparoscopic-assisted sigmoid colectomy offers benefits of decreased ileus and length of stay and may represent the procedure of choice for elective resection for uncomplicated sigmoid diverticulitis.

Adult↗
PubMed2006

[Clinical research on effects of yunpi zhixie granule in children with diarrhea].

OBJECTIVE: To investigate the clinical effect of Yunpi Zhixie Granule (YZG) on children's diarrhea. METHODS: Three hundred diarrhea cases were randomly divided into two groups equally, the treated group treated by YZG orally and the control group by smacta, both for 7 days. The clinical efficacy was observed, routine scatologic analysis, scatologic cultivation, rotavirus antigen and urinary D-xylose content were detected. RESULTS: Clinical results showed the effective rate in treating the chronic or Pi-deficiency diarrhea as well as the negative conversion rate and improvement rate of routine scatologic analysis were all higher in the treated group than those in the control group (P < 0.05); while no significant difference was found in negative conversion rate of scatologic cultivation and rotavirus antigen and urinary D-xylose content after treatment, compared with those before treatment (P > 0.05). CONCLUSION: YZG was effective in treating children' s diarrhea, especially on chronic diarrhea and diarrhea of Pi-deficiency type.

Administration, Oral↗
PubMed1997

Evidence for AT-transversion bias in wasp (Hymenoptera: Symphyta) mitochondrial genes and its implications for the origin of parasitism.

We inferred the incidence of nucleotide conversions in the COI and 16S rRNA mitochondrial genes of members of the Symphyta and basal Apocrita (Hymenoptera). Character-state reconstructions in both genes suggested that conversions between A and T (AT transversions) occurred much more frequently than any other type of change, although we cannot wholly discount an underlying transition bias. Parsimony analysis of COI nucleotide characters did not recover phylogeny; e.g., neither the Tenthredinoidea nor Apocrita were recovered as monophyletic. However, analysis of COI amino acid characters did recover these relationships, as well as others based on fossil and morphological evidence. Analysis of 16S rRNA characters also recovered these relationships providing conversions between A and T were down-weighted. Analysis of the combined data sets gave relatively strong support for various relationships, suggesting that both data sets supported similar topographies. These data sets, both separately and combined, suggested that the phytophagous Siricidae were more closely related to the predominantly parasitic Apocrita than were the ectoparasitic Orussoidea. This suggests that the wasp parasitic lifestyle did not have a single origin, unless the Siricidae have more recently reverted to phytophagy. Alternatively, parasitism evolved twice independently, once in the Orussoidea and again in the Apocrita. The latter scenario is supported by the observation that the evolution of parasitism was accompanied by a tendency for the larvae to develop inside plant tissues. Adaptations that accompanied the movement of wasps into a confined, wood-boring habitat may have preadapted them to becoming ectoparasitic.

Adenine↗
PubMed2004

Comparison of laboratory and clinical wear rates of resin composites.

OBJECTIVE: The purpose of this study was to use wear simulation to develop wear rates for two modern composite systems and then compare these rates with clinical studies on the same materials. METHOD AND MATERIALS: A spring-loaded piston wear simulator was used to generate localized wear rates for P50 and Z100 at 100,000, 200,000, 300,000, and 400,000 cycles. Clinical studies on P50 and Z100 conducted at Creighton University and the Catholic University of Leuven were used for comparison of clinical wear to the laboratory values. Regression analysis was employed to define the wear rates. RESULTS: The laboratory wear rates determined with simulation for P50 and Z100 were similar. Clinical occlusal contact area (OCA) wear for P50 and Z100 had small differences and were pooled to provide comparison with laboratory data. Wear rates determined from linear regression analysis provided equivalency factors between laboratory localized wear and clinical OCA wear that could be used for future studies. Further regression analysis comparing OCA and generalized clinical wear allowed a conversion factor of 4.5 to be determined. CONCLUSION: Localized wear from laboratory simulation may be a useful predictor of localized clinical wear and also clinical generalized wear using a conversion factor.

Analysis of Variance↗
PubMed1995

Degree of tumour differentiation as a prognostic factor in advanced laryngeal cancer.

Degree of tumour differentiation as a prognostic factor in advanced laryngeal cancer. As part of a retrospective analysis on treatment results in 139 patients with advanced laryngeal squamous cell carcinoma (T3-4) differentiation grade of the tumour was analyzed as a prognostic factor. Univariate analysis differentiation grade was related to tumour size, presence of neck node metastasis and conversion of N-stage during follow-up. For statistical analysis, patients with G1-G2 and G3-G4 were grouped. Prognosis for G3-G4 carcinomas is significantly worse for disease specific survival (p < 0.025), due to significantly more regional recurrence (p = 0.05). At multivariate analysis it turned out that regional control and disease specific survival in patients with no palpable neck nodes were adversely affected by the histological degree of differentiation of the diagnostic biopsy. For this group of patients extensive treatment of neck nodes is recommended.

Adult↗
PubMed1998

International price comparisons for pharmaceuticals. Measurement and policy issues.

Cross-national price comparisons for pharmaceuticals are commonly used for two purposes. Comparisons based on a sample of products are used to draw conclusions about differences in average price levels. Cross-national comparisons applied to individual products are also used by governments to set domestic prices. This paper examines the major methodological issues raised by international price comparisons, focusing on measurement of differences in average price levels and the validity of policy conclusions drawn from such price comparison studies. It argues that valid measures of average price levels can only be obtained from comparisons based on a comprehensive or representative sample of products, appropriately weighted, following standard index number methods. Comparisons of individual product prices should take into account the manufacturer's entire product portfolio over time rather than focus narrowly on a single product at a point in time. Because of the great variation across countries in both the range of drug compounds available and the dosage forms, strengths and pack sizes for each compound, obtaining a broadly comprehensive or representative sample is problematical. If products are required to match on all dimensions, including molecule, manufacturer, strength and pack, as is common in most international price comparisons, then only a very small and unrepresentative sample of the drugs available in each country can be included in the analysis. A trade-off between the desire to compare only identical products and the need to compare a truly representative sample of a country's pharmaceutical market is therefore necessary. A valid comparison of average drug prices should include generics and over-the-counter products that are good substitutes for branded prescription drugs, with all forms, strengths and packs. To achieve this broad representation, however, the requirements of same manufacturer, same brand, dosage form, strength and pack size must be dropped. When such an approach is taken to the comparison of international drug prices, quite different results from those obtained from less comprehensive comparisons may be obtained. Indeed, a major conclusion of this analysis is that international drug price comparisons are extremely sensitive to choices made about certain key methodological issues, such as sample selection, unit of measurement for price and volume, the relative weight given to consumption patterns in the countries being compared, and the use of exchange rates or purchasing power parities for currency conversion. In particular, the results of this analysis indicate that recent reports suggesting that manufacturer prices in the US are 32% higher than in Canada and 60% higher than in the UK are in fact overstatements which arise from limitations of the sample and methods used to calculate these price differentials.

Dosage Forms↗
PubMed1986

Topography of visual event-related potentials during geometric and phonetic discriminations.

Event-related potentials (ERPs) were obtained to letters during 3 tasks that involved a SIMPLE RESPONSE (SR) to each letter presentation, a FORM discrimination of the letters that formed a closed loop, and a RHYME discrimination of the letters that rhymed with the letter 'v'. The first task only required detection of the letters, the FORM task required a visual-spatial analysis, and the RHYME task, a grapheme-phoneme conversion of the letters followed by a determination of rhyming characteristics. The SR ERPs were morphologically different from the discriminative ERPs, notably by the absence of N2 and P3. The difference wave forms between the discrimination and SR conditions and between the targets and non-targets indicated differential topographies of components associated with the FORM and RHYME tasks in the 300 msec latency region. In both of these tasks, components exhibited distributions localized primarily in the occipital regions, whereas in the RHYME task they extended more anteriorly and encompassed temporo-parietal regions. Thus, although the stimulus presentation was visual, the requirement of a visual-auditory conversion in the RHYME task resulted in activity that was more proximal to auditory regions than when only a FORM analysis of the letters was required.

Adult↗
PubMed2004

[Laparoscopic repair of perforated duodenal ulcer: early postoperative results and risk factors].

BACKGROUND: Clear patient selection criteria and indications for laparoscopic repair of perforated duodenal ulcers are still of relevance. The purpose of our paper is to describe the early outcome results after this operation and to define the risk factors influencing the genesis of postoperative morbidity. PATIENTS AND METHODS: Fifty-one patients were operated on laparoscopically between October 1996 and October 2003 for perforated peptic ulcers. Out of them, 47 patients with perforated duodenal ulcers entered the final retrospective analysis. Twenty variables were identified, including the duration of acute symptoms before the operation, shock, underlying medical illness, ulcer size, age, Boey score and the predictive value of these variables for morbidity, conversion rates and hospital stay. The univariate data analysis was originally done using the Fisher exact test, t test, Mann Whitney, ANOVA and F tests. The data was reevaluated using multifactorial analysis with logistic and linear regression tests. RESULTS: Patient's age was 32.0+/-12.4 years. Duration of perforation was 8.0+/-10.8 hours. Shock was diagnosed in one patient (2.1%). High surgical risk according to ASA (III-IV) was estimated in 2 patients (4.3%). Laparoscopic duodenography was completed in 36 patients (76.6%). The other 11 patients (23.4%) underwent a conversion to open repair. Seven patients (19.4%) had postoperative complications. Suture leakage was confirmed in 4 patients (11.1%), and other abdominal complications were observed in 3 patients (8.3%). Pneumonia and pneumothorax were diagnosed in 3 patients. Hospital stay was 7.9+/-5.8 (4-45) days. There was no mortality. Ulcer perforation size >4-10 mm is the only significant risk factor influencing the conversion rate. An increase in the suture leakage rate was most significant with delayed presentation of >or=10 hours (p<0.0001). This risk factor influences both the postoperative pneumonia rate (>or=10 hrs., p=0.026) and hospital stay (p<0.05). CONCLUSION: Size of duodenal ulcer perforation and duration of ulcer perforation symptoms were found to be risk factors influencing the rates of conversion to open repair and genesis of postoperative morbidity.

Adolescent↗
PubMed2003

Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network.

The aim of this study was to explore whether there are networks of regions where maturation of white matter and changes in brain activity show similar developmental trends during childhood. In a previous study, we showed that during childhood, grey matter activity increases in frontal and parietal regions. We hypothesized that this would be mediated by maturation of white matter. Twenty-three healthy children aged 8-18 years were investigated. Brain activity was measured using the blood oxygen level-dependent (BOLD) contrast with functional magnetic resonance imaging (fMRI) during performance of a working memory (WM) task. White matter microstructure was investigated using diffusion tensor imaging (DTI). Based on the DTI data, we calculated fractional anisotropy (FA), an indicator of myelination and axon thickness. Prior to scanning, WM score was evaluated. WM score correlated independently with FA values and BOLD response in several regions. FA values and BOLD response were extracted for each subject from the peak voxels of these regions. The FA values were used as covariates in an additional BOLD analysis to find brain regions where FA values and BOLD response correlated. Conversely, the BOLD response values were used as covariates in an additional FA analysis. In several cortical and sub-cortical regions, there were positive correlations between maturation of white matter and increased brain activity. Specifically, and consistent with our hypothesis, we found that FA values in fronto-parietal white matter correlated with BOLD response in closely located grey matter in the superior frontal sulcus and inferior parietal lobe, areas that could form a functional network underlying working memory function.

Adolescent↗
PubMed1998

Repeat instability at human minisatellites arising from meiotic recombination.

Little is known about the role of meiotic recombination processes such as unequal crossover in driving instability at tandem repeat DNA. Methods have therefore been developed to detect meiotic crossovers within two different GC-rich minisatellite repeat arrays in humans, both in families and in sperm DNA. Both loci normally mutate in the germline by complex conversion-like transfer of repeats between alleles. Analysis shows that inter-allelic unequal crossovers also occur at both loci, although at low frequency, to yield simple recombinant repeat arrays with exchange of flanking markers. Equal crossovers between aligned alleles, resulting in recombinant alleles but without change in repeat copy number, also occur in sperm at a similar frequency to unequal crossovers. Both crossover and conversion show polarity in the repeat array and are co-suppressed in an allele showing unusual germline stability. This provides evidence that minisatellite conversion and crossover arise by a common mechanism, perhaps by alternative processing of a meiotic recombination initiation complex, and implies that minisatellite instability is a by-product of meiotic recombination in repeat DNA. While minisatellite recombination is infrequent, crossover rates indicate that the unstable end of a human minisatellite can act as a recombination warm-spot, even between sequence-heterologous alleles.

Crossing Over, Genetic↗
PubMed1998

Symptomatic cholelithiasis: a different disease in men? Connecticut Laparoscopic Cholesystectomy Registry.

OBJECTIVE: To determine the importance of gender in the clinical presentation and subsequent clinical outcome (risk of conversion from laparoscopic to open technique and risk of postoperative mortality) for patients undergoing cholecystectomy. SUMMARY BACKGROUND DATA: Age and clinical presentation have consistently been found to be important predictors of cholecystectomy outcomes; male gender has been cited in disparate studies as possibly having prognostic significance. METHOD: A statewide cholecystectomy registry (30,145 cases between 1989-1993) was analyzed. Hierarchical log-linear modeling was used to identify associations between characteristics of clinical presentation. Multivariate logistic regression analysis was used to determine predictions of conversion and mortality. RESULTS: Male gender was associated with twice the expected incidence of acute cholecystitis and pancreatitis in the elderly (> or = 65 years). Males had a significantly increased risk for conversion to open technique, but this decreased during the time frame of the study. Mortality was twice as high among males (confidence interval, 1.4-2.9, p = 0.0001). CONCLUSIONS: Males presenting for cholecystectomy are more likely to have severe disease. Independent of clinical presentation, they face increased risks of conversion to open technique and of postoperative mortality.

Aged↗
PubMed2002

Prenatal diagnosis of 21-hydroxylase deficiency caused by gene conversion and rearrangements: pitfalls and molecular diagnostic solutions.

OBJECTIVES: The present paper reports the prenatal diagnosis of congenital adrenal hyperplasia (CAH) in two cases of 21-hydroxylase deficiency. DNA diagnostic errors can be caused by the presence of the highly homologous 21-hydroxylase pseudogene, CYP21P, adjacent to the functional gene, CYP21. The present paper details how complex gene conversions and rearrangements between the CYP21 and CYP21P pose unique complications for prenatal diagnosis. METHODS: Analysis of eight common mutations in the 21-hydroxylase gene as well as deletion of the entire gene is accomplished using polymerase chin reaction (PCR) followed by amplified created restriction site (ACRS) or allele-specific oligohybridization (ASO) and Southern blot followed by hybridization to a CYP21-specific probe. Linkage analysis was performed using microsatellite markers flanking the CYP21 gene. RESULTS: The direct mutation detection assay indicated a complicated gene conversion and rearrangement in the probands of both families. Interpretation of these rearrangements made it difficult to determine whether or not the fetuses would be affected with CAH. Linkage studies revealed that each fetus had inherited both parental disease chromosomes and was therefore predicted to be affected with CAH. CONCLUSION: As observed in the two reported cases, direct DNA analysis may provide limited information due to gene conversion or rearrangement between the CYP21 and CYP21P genes. These cases suggest that direct mutation detection should be supported by linkage analysis, whenever possible, to provide more comprehensive information for the family.

Adrenal Hyperplasia, Congenital↗
PubMed1977

Gas chromatographic analysis of acetophenone oxime and its metabolites.

A gas-liquid chromatographic (GLC) method has been developed for monitoring the metabolic reduction of acetophenone oxime or oxidative metabolism of the corresponding amine, alpha-methylbenzylamine in liver homogenates. The oxime, amine, n-hydroxy-alpha-methylbenzylamine and acetophenone are quantitatively determined after GLC separation of components with temperature programming on an SP-2401-DB-coated column. The first three compounds were silylated with N,O-bis(trimethylsilyl)-acetamide prior to chromatographic analysis to enhance the stability and improve the chromatographic properties of these components. The effluent gas was monitored with flame ionization detection, and permitted quantitation of components at sub-microgram/ml levels with reproducibility between injections of +/-2%. The optimal composition of enantiomeric mixtures of (R,S)-alpha-methylbenzylamines formed during metabolic reduction of acetophenone oximes were determined by conversion to diastereomeric amides and subsequent GLC analysis.

Acetophenones↗
PubMed1977

Automated high-speed analysis of gastrointestinal myoelectric activity.

The value of myoelectric recording in the gastrointestinal tract has been limited by the difficulty of analyzing the prolonged recordings which are required to demonstrate integrated physiological activity. This problem has been solved by the use of a tape recording system with accelerated replay, originally developed for cardiac monitoring. Rapid replay not only reduces the time required for data retrieval but also increases the frequency of the recorded signals to allow electronic separation of fast and slow wave activity for on-line conversion into digital pulses suitable for computer analysis. The technique is illustrated by the analysis of an imperfect prolonged multichannel recording of cannine gastrointestinal myoelectric activity, demonstrating some of the possibilities for data analysis and error detection inherent in the system.

Animals↗
PubMed1995

Interactions between residues in staphylococcal alpha-hemolysin revealed by reversion mutagenesis.

alpha-Hemolysin (alpha HL), a pore-forming polypeptide of 293 amino acids, is secreted by Staphylococcus aureus as a water-soluble monomer. Residues that play key roles in the formation of functional heptameric pores on rabbit red blood cells (rRBC) have been identified previously by site-directed mutagenesis. alpha HL-H35N, in which the histidine at position 35 of the wild-type sequence is replaced with asparagine, is nonlytic and is arrested in assembly as a heptameric prepore. In this study, second-site revertants of H35N that have the ability to lyse rRBC were generated by error-prone PCR under conditions designed to produce single base changes. The analysis of 22 revertants revealed new codons clustered predominantly in three distinct regions of the H35N gene. One cluster includes amino acids 107-111 (four revertants) and another residues 144-155 (five revertants). These two clusters flank the central glycine-rich loop of alpha HL, which previously has been implicated in formation of the transmembrane channel, and encompass residues Lys-110 and Asp-152 that, like His-35, are crucial for lytic activity. The third cluster lies in the region spanning amino acids 217-228 (eight revertants), a region previously unexplored by mutagenesis. Single revertants were found at amino acid positions 84 and 169. When compared with H35N, the heptameric prepores formed by the revertants underwent more rapid conversion to fully assembled pores, as determined by conformational analysis by limited proteolysis. The rate of conversion to the fully assembled pore was strongly correlated with hemolytic activity. Previous work has suggested that the N terminus of alpha HL and the central loop cooperate in the final step of assembly. The present study suggests that the key N-terminal residue His-35 operates in conjunction with residues flanking the loop and C-terminal residues in the region 217-228. Hence, reversion mutagenesis extends the linear analysis that has been provided by direct point mutagenesis.

Amino Acid Sequence↗
PubMed2003

Cloning, purification, crystallization and preliminary crystallographic analysis of galactokinase from Pyrococcus furiosus.

Galactokinase catalyses the conversion of galactose to galactose-1-phosphate as the first step in the Leloir pathway, a metabolic route that eventually enables the degradation of galactose via the glycolytic pathway. Galactokinases have been isolated from a wide range of prokaryotic and eukaryotic organisms and the enzyme has been identified as a member of the GHMP kinase (galactokinase, homoserine kinase, mevalonate kinase and phosphomevalonate kinase) superfamily. Pyrococcus furiosus galactokinase was cloned, expressed in Escherichia coli, purified and crystallized using the hanging-drop method of vapour diffusion with ammonium sulfate as the precipitant. The crystals belong to the space group C222(1), with more than eight subunits in the asymmetric unit and with approximate unit-cell parameters a = 211.7, b = 355.4, c = 165.5 A, alpha = beta = gamma = 90 degrees. The crystals diffract X-rays to 2.9 A resolution on a synchrotron-radiation source. Determination of the structure will provide insights into the molecular basis of substrate recognition and catalysis of this enzyme, for which no structures are currently available.

Cloning, Molecular↗
PubMed1979

Analysis of in vitro replication of different DNAs.

The conversion of single-stranded circular DNA to duplex DNA in vitro occurs by at least three different mechanisms. These differences reside in the manner of priming of these DNAs. In contrast, the elongation of primed DNA templates is a general reaction. A number of these proteins have been isolated and further characterized. In addition, cell-free preparations capable of supporting phi X RFI DNA replication as well as the synthesis of progeny viral phi X174 single-stranded circular DNA have been prepared.

Coliphages↗
PubMed2004

[Outcome of pulmonary Mycobacterium avium complex (MAC) disease treated with clarithromycin (CAM)-containing regimens].

We retrospectively investigated the efficacy of regimens including clarithromycin (CAM) in 129 patients with Mycobacterium avium complex (MAC) pulmonary disease and their outcomes. None of the patients suffered from acquired immunodeficiency syndrome. All were observed for over 12 months. We studied the factors that may affect sputum conversion and fatal outcomes by logistic regression analysis. The results indicated that the presence of either cavitation or bronchiectasis was significantly correlated with persistent MAC-positive culture results in sputum (Odds ratio, 4.71, 95%; CL, 1.21-18.5; P<0.05). Regimens including antituberculous drugs and CAM were administered to 118 patients, 11 of whom received CAM alone because of the adverse events of antituberculous agents. There was no difference in sputum conversion or mortality between the two groups, suggesting that the pattern of drug combination should be further investigated.

Aged↗