Seroprevalence of dengue antibodies, annual incidence and risk factors among children in southern Vietnam

Dengue is highly endemic in southern Vietnam and all four serotypes of dengue virus have already been identified. To determine the age-specific prevalence of dengue and associated risk factors, we conducted a serological study at two primary schools and assessed risk factors by analysing children's questionnaires and household surveys. Sera were collected from 961 primary schoolchildren in Binh Thuan Province and tested for the presence of dengue virus serum antibodies using an indirect immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). The antibody prevalence of the total population was 65.7% (n=631) which increased from 53.0 to 88.2% with age. The annual incidence of a first dengue infection, estimated by binary regression of the seroprevalence by age, was 11.7%. Interestingly, the prevalence of dengue IgG antibodies was significantly higher in children who confirmed using a pit latrine (RR 1.467, 95% CI: 1.245-1.730) and whose domestic environment contained discarded cans (RR 1.238, 95% CI: 1.042-1.470) and pigs (RR 1.228, 95% CI: 1.002-1.504). The epidemiology of dengue in southern Vietnam is stable with a constantly high annual incidence of first infections. Transmission occurs mainly peri-domestically, which has important public health implications.     

Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men

Free fatty acid (FFA)– and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in human skeletal muscle. Whether FAs have a direct effect on intrinsic mitochondrial capacity remains to be established. Therefore, we measured ex vivo mitochondrial respiratory capacity in human skeletal muscle after exposure to hyperinsulinemia and high levels of plasma FFA. Nine healthy lean men were studied during a 6-hour hyperinsulinemic (600 pmol/L) euglycemic clamp with concomitant infusion of Intralipid (Fresensius Kabi Nederland, Den Bosch, the Netherlands) (FFA clamped at 0.5 mmol/L) or saline. Mitochondrial respiratory capacity was measured by high-resolution respirometry in permeabilized muscle fibers using an Oxygraph (OROBOROS Instruments, Innsbruck, Austria). Each participant served as his own control. Peripheral glucose uptake (rate of disappearance) was significantly lower during infusion of the lipid emulsion compared with the control saline infusion (68 μmol/kg·min [saline] vs 40 μmol/kg·min [lipid], P = .008). However, adenosine diphosphate–stimulated and maximal carbonylcyanide-4-(trifluoromethoxy)-phenylhydrazone–stimulated uncoupled respiration rates were not different in permeabilized skeletal muscle fibers after exposure to high levels of FFA compared with the control condition. We conclude that short-term elevation of FFA within the physiological range induces insulin resistance but does not affect intrinsic mitochondrial capacity in skeletal muscle in humans.     

Pseudoaneurysm following laparoscopic cholecystectomy

BACKGROUND:Laparoscopic cholecystectomy(LC)is the operation of choice for removal of the gallbladder. Unrecognized bile duct injuries present with biliary peritonitis and systemic sepsis.Bile has been shown to cause damage to the vascular wall and therefore delay the healing of injured arteries leading to pseudoaneurysm formation.Failure to deal with bile leak and secondary infection may result in pseudoaneurysm formation. This study was to report the incidence and outcomes of pseudoaneurysm in patients with bile leak following LC referred to our hospital. METHODS:A retrospective analysis of our prospectively maintained liver database using pseudoaneurysm, bile leak and bile duct injury following laparoscopic cholecystectomy from January 2000 to December 2005 was performed. RESULTS:A total of 86 cases were referred with bile duct injury and bile leak following LC and of these,4 patients (4.5%)developed hepatic artery pseudoaneurysm(HAP) presenting with haemobilia in 3 and massive intra- abdominal bleed in 1.Selective visceral angiography confirmed pseudoaneurysm of the right hepatic artery in 2 cases,cystic artery stump in one and an intact but ectatic hepatic artery with surgical clips closely applied to the right hepatic artery at the origin of the cystic artery in the fourth case.Effective hemostasis was achieved in 3 patients with coil embolization and the fourth patient required emergency laparotomy for severe bleeding and hemodynamic instability due to a ruptured right hepatic artery.Of the 3 patients treated with coil embolization, 2 developed late strictures of the common hepatic duct. . (CHD)requiring hepatico-jejunostomy and one developed a stricture of left hepatic duct.All the 4 patients are alive at a median follow up of 17 months(range 1 to 65)with normal liver function tests. CONCLUSIONS:HAP is a rare and potentially life- threatening complication of LC.Biloma and subsequent infection are reported to be associated with pseudoaneurysm formation.Late duct stricture is common either due to unrecognized injury at LC or secondary to ischemia after embolization.     

Hydrophilic bile salts enhance differential distribution of sphingomyelin and phosphatidylcholine between micellar and vesicular phases: potential implications for their effects in vivo

BACKGROUND/AIMS: The hepatocyte canalicular membrane outer leaflet contains both phosphatidylcholine (PC) and sphingomyelin (SM). Normally, PC is the exclusive phospholipid in bile. We examined effects of bile salt hydrophobicity on cytotoxicity and on differential SM and PC distribution between detergent-resistant aggregated vesicles (model for detergent-resistant canalicular membrane) and mixed micelles or small unilamellar vesicles (representing lipid phases in bile). METHODS: Aggregated vesicles were obtained by ultracentrifugation of cholesterol-supersaturated model systems containing SM, PC and various bile salts, micelles by ultrafiltration and unilamellar vesicles by dialysis of the supernatant. Erythrocyte hemolysis and lactate dehydrogenase release from CaCo-2 cells upon incubation with various micelles were quantified. RESULTS: Preferential SM distribution and lipid solubilization in aggregated vesicles increased in rank order taurodeoxycholate < taurocholate < tauroursodeoxycholate < taurohyodeoxycholate, with reciprocal PC enrichment in micelles and small unilamellar vesicles. Including small amounts of PC within taurohyodeoxycholate micelles increased cytotoxicity with more erythrocyte hemolysis and LDH release from CaCo-2 cells upon incubation, but decreased cytotoxicity in case of tauroursodeoxycholate micelles. CONCLUSIONS: Hydrophilic but not hydrophobic bile salts preserve integrity of pathophysiologically relevant phosphatidylcholine plus sphingomyelin-containing bilayers. Enhanced biliary phospholipid secretion during taurohyodeoxycholate but not during tauroursodeoxycholate therapy (Hepatology 25 (1997) 1306) may relate to different interactions of these bile salts with phospholipids.     

Objective Differences in Colonoscopy Technique Between Trainee and Expert Endoscopists Using the Colonoscopy Force Monitor

Background

Learning to perform colonoscopy safely and effectively is central to gastroenterology fellowship programs. The application of force to the colonoscope is an important part of colonoscopy technique.

Aims

We compared force application during colonoscopy between novice and expert endoscopists using a novel device to determine differences in colonoscopy technique.

Methods

This is an observational cohort study designed to compare force application during colonoscopy between novice and experienced trainees, made up of gastroenterology fellows from two training programs, and expert endoscopists from both academic and private practice settings.

Results

Force recordings were obtained for 257 colonoscopies by 37 endoscopists, 21 of whom were trainees. Experts used higher average forward forces during insertion compared to all trainees and significantly less clockwise torque compared to novice trainees.

Conclusions

We present significant, objective differences in colonoscopy technique between novice trainees, experienced trainees, and expert endoscopists. These findings suggest that the colonoscopy force monitor is an objective tool for measuring proficiency in colonoscopy. Furthermore, the device may be used as a teaching tool in training and continued medical education programs.

     

Systematic review of prognostic importance of extramural venous invasion in rectal cancer

AIM: To systematically review the survival outcomes relating to extramural venous invasion in rectal cancer.METHODS: A systematic review was conducted using PRISMA guidelines. An electronic search was carried out using MEDLINE, EMBASE, CINAHL, Cochrane library databases, Google scholar and Pub Med until October 2014. Search terms were used in combination to yield articles on extramural venous invasion in rectal cancer. Outcome measures included prevalence and 5-year survival rates. These were graphically displayed using Forest plots. Statistical analysis of the data was carried out.RESULTS: Fourteen studies reported the prevalence of extramural venous invasion(EMVI) positive patients. Prevalence ranged from 9%-61%. The pooled prevalence of EMVI positivity was 26% [Random effects: Event rate 0.26(0.18, 0.36)]. Most studies showed that EMVI related to worse oncological outcomes. The pooled overall survival was 39.5% [Random effects: Event rate 0.395(0.29, 0.51)].CONCLUSION: Historically, there has been huge variation in the prevalence of EMVI through inconsistent reporting. However the presence of EMVI clearly leads to worse survival outcomes. As detection rates become more consistent, EMVI may be considered as part of risk-stratification in rectal cancer. Standardised histopathological definitions and the use of magnetic resonance imaging to identify EMVI will improve detection rates in the future.     

A multitest regimen of pain provocation tests as an aid to reduce unnecessary minimally invasive sacroiliac joint procedures

OBJECTIVE: To compare the diagnostic accuracy of a multitest regimen of 5 sacroiliac joint (SIJ) pain provocation tests with fluoroscopically controlled double SIJ blocks using a short- and long-acting local anesthetic in order to reduce the exposure of patients to unnecessary invasive SIJ procedures. DESIGN: Prospective, observational study. SETTING: Hospital setting. PARTICIPANTS: Sixty patients with chronic low back pain. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Visual analog scale score and receiver operating characteristic (ROC) curve. RESULTS: Twenty-seven patients responded positively to the blocks, of whom 23 were found positive after the multitest regimen and 4 were negative. For the nonresponders (n=33), these figures were 7 positive and 26 negative. The calculated sensitivity and specificity were .85 (95% confidence interval [CI], .72-.99) and .79 (95% CI, .65-.93), respectively. Positive and negative predictive values were .77 (95% CI, .62-.92) and .87 (95% CI, .74-.99), respectively. The positive likelihood ratio was 4.02 (95% CI, 2.04-7.89); the negative likelihood ratio was .19 (95% CI, .07-.47). The area under the ROC curve was .799. CONCLUSIONS: The test regimen with 3 or more positive tests is indicative of SIJ pain. It can be used in early clinical decision making to reduce the number of unnecessary minimally invasive diagnostic SIJ procedures.     

Intestinal ABCA1 directly contributes to HDL biogenesis in vivo

Plasma HDL cholesterol levels are inversely related to risk for atherosclerosis. The ATP-binding cassette, subfamily A, member 1 (ABCA1) mediates the rate-controlling step in HDL particle formation, the assembly of free cholesterol and phospholipids with apoA-I. ABCA1 is expressed in many tissues; however, the physiological functions of ABCA1 in specific tissues and organs are still elusive. The liver is known to be the major source of plasma HDL, but it is likely that there are other important sites of HDL biogenesis. To assess the contribution of intestinal ABCA1 to plasma HDL levels in vivo, we generated mice that specifically lack ABCA1 in the intestine. Our results indicate that approximately 30% of the steady-state plasma HDL pool is contributed by intestinal ABCA1 in mice. In addition, our data suggest that HDL derived from intestinal ABCA1 is secreted directly into the circulation and that HDL in lymph is predominantly derived from the plasma compartment. These data establish a critical role for intestinal ABCA1 in plasma HDL biogenesis in vivo.     

Relevance of hereditary defects in lipid transport proteins for the pathogenesis of cholesterol gallstone disease

In the formation of cholesterol gallstones, cholesterol hypersecretion into bile causing cholesterol supersaturation and crystallization appears to be the primary factor, with disturbed gallbladder and intestinal motility as secondary factors. Although intestinal uptake mechanisms have not yet been fully elucidated, the HDL receptor scavenger receptor B1 (SRB1) may be involved. Since HDL-cholesterol, both from the intestine and peripheral sources, is the preferred type of cholesterol for biliary secretion, increased HDL transport to the liver can also cause cholesterol hypersecretion in bile. In the hepatocyte, bile formation is regulated by several transmembrane proteins, all belonging to the ABC family. A change in the activity in one of these proteins can have a profound impact on biliary lipid secretion. The bile salt export pump (BSEP or ABCB11) regulates the excretion of bile salts into bile and mutations cause severe cholestasis. The second ABC transporter, ABCB4 (MDR3) regulates the secretion in bile of phosphatidylcholine (PC), while ABCG5/G8 is active in the excretion of cholesterol and sterols into bile. These transporters also facilitate transport of sterols back into the intestinal lumen. Mutations in either of these genes cause sitosterolaemia with increased absorption of plant sterols and cholesterol. Until now, evidence for a genetic background of human gallstone disease is mostly indirect and based on ethnic differences. Only two single gene defects are associated with gallstones. One is an ABCB4 mutation which causes a deficiency in biliary PC secretion and the other is a CYP7A1 mutation, the rate-limiting enzyme in the synthesis of bile salts from cholesterol in the liver. Recently, several common DNA polymorphisms in the ABCG8 gene were discovered that are associated with variations in plasma sterols, which could also influence biliary cholesterol secretion, but there is still a paucity of human studies.     

Transplantation of enriched and purged peripheral blood progenitor cells from a single apheresis product in patients with non-Hodgkin's lymphoma

High-dose chemotherapy with or without radiotherapy followed by autologous transplantation of hematopoietic progenitor cells is an effective treatment for patients with high-risk or relapsed non- Hodgkin's lymphoma. Chemotherapy and/or hematopoietic growth factors have been used to mobilize progenitor cells in the peripheral blood for transplantation. However, the mobilized blood cell products have been found to be frequently contaminated with tumor cells, and techniques have not been developed to purge tumor cells from these products. In addition, the minimum number of hematopoietic progenitor cells required for engraftment has not yet been fully elucidated. We treated 21 patients with a single infusion of cyclophosphamide (4 g/m2) followed by daily administration of granulocyte colony-stimulating factor (G- CSF). After recovery of the white blood cell count, a single 3-hour apheresis collection was performed. The apheresis product was then applied to a discontinuous Percoll gradient. The low-density fractions resulting from this separation procedure were enriched for CD34+ progenitor cells (total cell yield, 19.5%; CD34+ cell recovery, 81.2%). These enriched cellular products were treated with a panel of anti-B cell or anti-T cell monoclonal antibodies and complement in an effort to remove residual tumor cells. After treatment of the patient with myeloablative therapies, the enriched and purged cells were reinfused. Hematologic recovery was rapid, with median neutrophil engraftment in 10 days [absolute neutrophil count (ANC), greater than 0.5 x 10(9)/L] and 11 days (ANC, greater than 1.0 x 10(9)/L). Median platelet transfusion independence required 13 days. The rapidity of multilineage engraftment correlated with the number of CD34+ cells per kilogram that were infused. Patients who received more than 2 x 10(6) CD34+ cells per kilogram had rapid hematologic engraftment, whereas those patients transplanted with less than 2 x 10(6) CD34+ cells per kilogram had slower platelet recovery. Modeling studies using a lymphoma cell line with a t(14; 18) chromosomal translocation demonstrated the successful removal of tumor cells assayed using the polymerase chain reaction (PCR) after the processing and purging. Four of the 21 patients had PCR- detectable lymphoma cells in the bone marrow and peripheral blood; however, the enriched and purged blood products reinfused in all four did not contain detectable tumor cells.(ABSTRACT TRUNCATED AT 400 WORDS)