The genetic structure and history of Africans and African Americans.

Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (approximately 71%), European (approximately 13%), and other African (approximately 8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies.

Resectability and prognostic factors after resection of hilar cholangiocarcinoma.

BACKGROUND/AIMS: Hilar cholangiocarcinoma, still a challenging problem for surgeons and resectional surgery, is the treatment of choice for long-term survival. In this study we tried to evaluate different prognostic factors after resection. METHODOLOGY: From January 1995 to October 2004, 440 patients with hilar cholangiocarcinoma were admitted to the Gastroenterology Surgical Center, Mansoura University, Egypt. Of these patients 73 underwent potentially curative resection giving respectability rate of 17%, and the remaining 367 patients underwent non-surgical treatment because of advanced disease, advanced cirrhosis and poor general condition. Of the 73 patients, 35 (48%) underwent localized hepatic resection and 38 (52%) patients underwent major hepatic resection. Various prognostic factors for survival were evaluated by univariate and multivariate analysis. RESULTS: Hospital mortality occurred in 8 (11%) patients. The most common postoperative complications were: bile leak, liver cell failure and wound infection 23.2%, 17.8% and 9.5% respectively. The survival rates at 1, 2, 3, 4, and 5 years were 79%, 32.6, 18.5, 137% and 13% respectively. The result of univariate analysis revealed that radicality of resection, lymph nodes status, tumor differentiation, modified Bismuth staging, underlying liver pathology, HCV viral infection, blood transfusion, preoperative serum bilirubin <10mg and CA19-9 are dependent prognostic factors. By multivariate Cox analysis radicality of resection, lymph nodes status, serum bilirubin below 10mg/dL level of CA19-9 and hepatitis viral infection were independent predictor factors. CONCLUSIONS: From this study we found that aggressive surgical procedure to obtain curative resection with preoperative serum bilirubin below 10mg and HCV infective negative especially in noncirrhotic liver may bring a better prognosis in hilar cholangiocarcinoma.

Prevalence of Helicobacter pylori, gastric myoelectrical activity, gastric mucosal changes and dyspeptic symptoms before and after laparoscopic cholecystectomy.

BACKGROUND/AIMS: Cholecystectomy may lead to anatomic and functional alterations which eventually induce reflux of duodenal contents with its sequlae. The aim of this study is to evaluate the prevalence of Helicobacter pylori (H. pylori), gastric myoelectrical activities and gastric mucosal changes before and after laparoscopic cholecystectomy. METHODOLOGY: This prospective study has been carried out on 46 patients (20 M & 26 F) with mean age 41.7+/-0.2 years for whom laparoscopic cholecystectomy for gallstones was carried out. Prior to the operation and 1 year after, all patients were subjected to clinical assessment, upper gastrointestinal endoscopy, histopathology of antral mucosa, reflux gastritis score, detection of H. pylori and electrogastrography. RESULTS: There was an increase in the postoperative suggestive symptoms of reflux gastritis compared to the preoperative: epigastric pain increased from 8 (17.4%) to 11 (23.39%) patients, nausea increased from 6 (13%) to 12 (26.1%) and bilious vomiting increased from 3 (6.5%) to 11 (23.9%) patients. Mild antral gastritis was detected endoscopically before laparoscopic cholecystectomy in 20 patients (43.5%) and increased to 27 patients (58.7%) after surgery. Meanwhile, severe antral gastritis and erosions were only detected after the operation in 10 (21.7%) patients, respectively. The histological results showed an increase of the histopathologic score of reflux gastritis after cholecystectomy from 4.28 (+/-1.56) to 9.28 (+/-1.99) (p<0.001). Active chronic superficial gastritis decreased from 23 (50%) to 13 (28.2%) patients while the inactive form increased from 15 (32.6%) to 23 (50%) patients. Also, chronic atrophic gastritis, intestinal metaplasia and dysplasia were detected postoperatively in 4 (8.6%) patients. The incidence of H. pylori infection was decreased from 32 (69.6%) to 19 (41.3%) patients (p<0.0001). Electrogastrography abnormal frequency decreased in fasting from 26.1% to 8.7% (p<0.001), and postprandial from 16.9% to 4.4% recording (p<0.002). On the other hand, there was an increase in the number of patients with decreased electrogastrography amplitude after a meal from 4.3% to 28.3% (p<0.0001). CONCLUSIONS: Our study shows that dyspeptic symptoms, endoscopic and histologic gastric changes as well as electrogastrography abnormalities are present before and increase after cholecystectomy; meanwhile H. pylori colonization in gastric mucosa is decreased after cholecystectomy.

High-performance liquid chromatographic analysis of vancomycin in plasma, bone, atrial appendage tissue and pericardial fluid.

Solid-phase extraction coupled with reversed-phase high-performance liquid chromatography and UV detection was employed for the analysis of the antibiotic vancomycin in patient plasma, bone, atrial appendage, and pericardial fluid. Vancomycin was quantitated in samples from patients undergoing cardiac surgery. Calibrations were linear in the range 3-100 micrograms/ml vancomycin; the lower limit of detection was approximately 3 micrograms/ml in fluids with an absolute limit of detection in bone samples of 0.75 microgram per injection.