Molecular genetic analysis of 675 group A streptococcus isolates collected in a carrier study at Lackland Air Force Base,San Antonio,Texas

Contemporary molecular genetic analysis methods have not been used to study large samples of carriage isolates of group A Streptococcus. To determine the emm types causing asymptomatic carriage and pharyngitis in a closed population, we analyzed 675 isolates recovered from a population-based surveillance study of 10,634 recruits at Lackland Air Force Base, Texas, during 4 months in 1993-1994. Strains with emm1 and emm6 alleles accounted for only 22% of the isolates recovered from asymptomatic recruits at entrance to training. However, these 2 emm types caused 69% of the pharyngitis cases identified during training and represented 51% of the isolates recovered from the throat on exit from training. Sequence analysis of the hypervariable sic gene documented that distinct emm1 subclones disseminated in specific training groups called flights. The preferential increase in the prevalence of emm1 and emm6 isolates during the 6-week training period indicates an enhanced ability of these strains to disseminate and cause disease in this population.     

Molecular epidemiology of fecal Oxalobacter formigenes in healthy adults living in Seoul,Korea

BACKGROUND AND PURPOSE: Oxalobacter formigenes is a member of the intestinal flora that degrades oxalate. This bacterium maintains an important symbiotic relation with its hosts by regulating oxalic acid absorption in the intestine as well as oxalic acid concentrations in plasma. We tried to define the prevalence of fecal O. formigenes positivity in healthy adults. MATERIALS AND METHODS: Whole-bacterial DNA was isolated directly from fresh stool samples obtained from 233 healthy adults known to be free of urolithiasis. Genus-specific oligonucleotide sequences corresponding to homologous regions residing in the oxc gene that encodes oxalyl-coenzyme A decarboxylase were designed. A PCR-based assay was done on the stool samples. RESULTS: A PCR product of 416 bp encoding the oxc gene was detected in 197 of the 233 stool samples (76.8%). Adjusted to the Seoul population census 1995, the calibrated fecal O. formigenes-positive rate was estimated to be 76.7%: 79.2% in men and 74.2% in women, with no significance difference according to age or sex. CONCLUSION: These results suggest that O. formigenes inhabits the intestine of three fourths of the normal Korean populations. These data provide a base for further studies to uncover the relation between O. formigenes and urolithiasis.     

RNA expression patterns change dramatically in human neutrophils exposed to bacteria

A comprehensive study of changes in messenger RNA (mRNA) levels in human neutrophils following exposure to bacteria is described. Within 2 hours there are dramatic changes in the levels of several hundred mRNAs including those for a variety of cytokines, receptors, apoptosis-regulating products, and membrane trafficking regulators. In addition, there are a large number of up-regulated mRNAs that appear to represent a common core of activation response genes that have been identified as early-response products to a variety of stimuli in a number of other cell types. The activation response of neutrophils to nonpathogenic bacteria is greatly altered by exposure to Yersinia pestis, which may be a major factor contributing to the virulence and rapid progression of plague. Several gene clusters were created based on the patterns of gene induction caused by different bacteria. These clusters were consistent with those found by a principal components analysis. A number of the changes could be interpreted in terms of neutrophil physiology and the known functions of the genes. These findings indicate that active regulation of gene expression plays a major role in the neutrophil contribution to the cellular inflammatory response. Interruption of these changes by pathogens, such as Y pestis, could be responsible, at least in part, for the failure to contain infections by highly virulent organisms.     

Effect of supplementation of vitamin E and vitamin C on brain acetylcholinesterase activity and neurotransmitter levels in rats treated with scopolamine, an inducer of dementia

In the present study, the effects of vitamins E and C on the levels of neurotransmitters and acetylcholinesterase activity in the brains of rats treated with scopolamine, an inducer of dementia, were examined. Fifty male Sprague-Dawley rats at the age of 5 wk were divided into five groups after 1 wk of adaptation and fed five different diets for 6 wk: a no-scopolamine group, which was a scopolamine-untreated group fed only a basal diet: a scopolamine-treated group fed a basal diet; a vitamin E-supplemented scopolamine-treated group: a vitamin C-supplemented scopolamine-treated group; and a vitamins E and C-supplemented scopolamine-treated group. Scopolamine was twice administered by intraperitoneal injection (300 mg/kg, body weight), 3 d and 20 min prior to sacrifice. Brain acetylcholinesterase activity was markedly reduced by scopolamine injection. However, the supplementation of vitamins E and C in the diet significantly increased the reduced brain acetylcholinesterase activity up to the level of the scopolamine-untreated group. Brain serotonin concentration in the vitamin C-supplemented scopolamine-treated group was significantly higher than that in the scopolamine-treated group. However, there were no significant differences in brain dopamine and norepinephrine concentrations among all groups. In conclusion, supplementation with vitamin E and/or vitamin C might be useful in maintaining brain acetylcholinesterase activity at the normal level and serotonin concentration for some extent under the condition to induce dementia by scopolamine administration.     

Intrahepatic splenosis: imaging features

We report a patient who presented with asymptomatic focal liver lesions and in whom a diagnosis of intrahepatic splenosis was made. This rare condition mostly occurs in patients who previously underwent splenic trauma or surgery. Magnetic resonance imaging (MRI) characteristics suggesting this diagnosis are described. The lesions were mainly hypointense on T1- and hyperintense on T2-weighted images. After administration of small iron oxide particles (SPIO-Endorem), the lesions remained slightly hyperintense relative to the hypointense liver parenchyma but showed a 50% loss in signal intensity. Knowledge of these MRI characteristics may avoid the use of surgical interventions to arrive at the correct diagnosis of these rare liver lesions. Received: 14 June 1999/Accepted: 14 July 1999     

DengueInfo: A web portal to dengue information resources.

DengueInfo (http://www.dengueinfo.org) is a web portal and database that brings clarity to dengue research by integrating the growing number of complete genome sequences of dengue virus with relevant literature and curated epidemiological information. Additionally, it represents a repository of on-going prospective and retrospective studies of dengue disease severity. We intend the database to be a flagship resource for the dengue community, providing standardized and high quality information and facilitating research into key aspects of dengue biology and assisting in its control. To aid this process we also introduce a standard nomenclature for dengue isolates inspired by globally accepted system used for influenza virus.     

Ureteroenteric fistula after retrograde balloon dilatation of ureteral stricture.

Advances in endourology have made transluminal balloon dilatation a safe and effective procedure for the treatment of ureteral strictures. Bilateral ureteral stricture was treated with retrograde balloon dilatation and ureteral stenting in a 59-year-old-woman. The patient had previously undergone abdominoperineal resection and adjuvant radiotherapy due to rectosigmoid adenocarcinoma. Subsequently, unilateral ureteroenteric fistula was detected on follow-up retrograde ureteropyelography. To our knowledge, this is the first case of ureteroenteric fistula after balloon dilatation for ureteral stricture in a patient with predisposing factors for compromised vascularity of the ureter.     

Targeting regions with highest lipid content on MR spectroscopy may improve diagnostic yield in stereotactic biopsy.

Gliomas are heterogeneous brain tumors and prognosis and treatment are dependent on the highest histological grade present. Stereotactic biopsy is associated with an inherent risk of sampling error. Magnetic resonance spectroscopy (MRS) uses clinical MR scanners to provide chemical in addition to conventional information. MRS studies in brain tumors have found increased levels of choline-containing compounds (Cho) and decreased levels of N-acetylaspartate (NAA), creatine (Cr) and phosphocreatine (PCr) which are all associated with increased grade of glioma. We propose the use of MRS-guided stereotactic biopsy of astrocytomas to increase diagnostic yield and reduce the sampling error rate. MRS was performed on two patients undergoing stereotactic biopsy for suspected astrocytoma. Spectral peak heights of the metabolites Cho at 3.2 parts per million (ppm) chemical shift, NAA at 2.0 ppm and lipid (Lip) at 1.2 ppm, were measured. Biopsy targets were selected from the voxels with the highest Cho/NAA and normalised against Cho levels in the contralateral normal tissue, as well as those with highest lipid content. The biopsies were taken and tissue diagnosis was obtained via standard histological techniques. Histological grade was found to be different in one case: the region with a high Lip/Cr and Cho/NAA ratios showed glioblastoma, whereas the region with high Cho/NAA but low Lip/Cr ratios showed anaplastic astrocytoma. The second patient had high Cho/NAA ratio but low Lip/Cr ratio in both targets and the histology revealed anaplastic astrocytoma in both samples. MRS is a useful biomedical imaging tool for diagnosing and grading astrocytomas. Targeting regions with highest lipid content can potentially improve the diagnostic yield and minimize sampling error in stereotactic biopsy.