Molecular genetic diversity and genetic structure of Vietnamese indigenous pig populations.

The study characterized genetic diversity and genetic structure of five indigenous pig populations (Ha Lang, Muong Te, Mong Cai, Lung and Lung Pu), two wild pig populations (Vietnamese and Thai wild pigs) and an exotic pig breed (Yorkshire) using FAO/ISAG recommended 16 microsatellite markers in 236 samples. All estimated loci were very polymorphic indicated by high values of polymorphism information content (from 0.76 in S0225 to 0.92 in Sw2410). Indigenous populations had very high level of genetic diversity (mean He = 0.75); of all indigenous breeds, Lung Pu showed highest mean number of alleles (MNA = 10.1), gene diversity (He = 0.82), allele richness (5.33) and number of private alleles (10). Thirteen percentage of the total genetic variation observed was due to differences among populations. The neighbour-joining dendrogram obtained from Nei's standard genetic distance differentiated eight populations into four groups including Yorkshire, two wild populations, Mong Cai population and a group of four other indigenous populations. The Bayesian clustering with the admixture model implemented in Structure 2.1 indicated seven possible homogenous clusters among eight populations. From 79% (Ha Lang) to 98% (Mong Cai). individuals in indigenous pigs were assigned to their own populations. The results confirmed high level of genetic diversity and shed a new light on genetic structure of Vietnam indigenous pig populations.

Mechanisms of neurovascular dysfunction in acute ischemic brain.

The neurovascular unit is now well accepted as a conceptual framework for investigating the mechanisms of ischemic stroke. From a molecular and cellular perspective, three broad mechanisms may underlie stroke pathophysiology--excitotoxicity, oxidative stress and inflammation. To date, however, most investigations of these basic mechanisms have focused on neuronal responses. In this mini-review, we ask whether these mechanisms of excitotoxicity, oxidative stress and inflammation can also be examined in terms of non-neuronal interactions in the neurovascular unit, including the release of extracellular vesicles for cell-cell signaling.

Statin use and neurologic morbidity after coronary artery bypass grafting: A cohort study.

BACKGROUND: Statin use before surgery has been associated with reduced morbidity and mortality after vascular surgery. The effect of preoperative statin use on stroke and encephalopathy after coronary artery bypass grafting (CABG) is unclear. METHODS: A post hoc analysis was undertaken of a prospectively collected cohort of isolated CABG patients over a 10-year period at a single institution. Primary outcomes were stroke and encephalopathy. Univariable analyses identified risk factors for statin use, which were applied to a propensity score model using logistic regression and patients were divided into quintiles of propensity for statin use. Controlling for propensity score quintile, the odds ratio (OR) of combined stroke and encephalopathy (primary endpoint), cardiovascular mortality, myocardial infarction, and length of stay were compared between statin users and nonusers. RESULTS: There were 5,121 CABG patients, of whom 2,788 (54%) were taking statin medications preoperatively. Stroke occurred in 166 (3.2%) and encephalopathy in 438 (8.6%), contributing to 604 patients (11.8%) who met the primary endpoint. The unadjusted OR of stroke/encephalopathy in statin users was 1.053 (95% confidence interval [CI] 0.888-1.248, p = 0.582). Adjustment based on propensity score resulted in balance of stroke risk factors among quintiles. The propensity score-adjusted OR of stroke/encephalopathy in statin users was 0.958 (95% CI 0.784-1.170, p = 0.674). There were no significant differences in cardiovascular mortality, myocardial infarction, or length of stay between statin users and otherwise similar nonusers. CONCLUSIONS: In this large data cohort study, preoperative statin use was not associated with a decreased incidence of stroke and encephalopathy after coronary artery bypass grafting.

Use of sequence analysis of the VP4 gene to classify recent Vietnamese rotavirus isolates.

Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh City, Vietnam, during 2002-2003, were investigated by sequence analysis of the VP4 gene. Seven of the 28 P(8) rotavirus VP4 sequences clustered in the P(8)-3 lineage, or the rare, so-called OP354-like lineage. Amino-acid sequence comparison revealed that Vietnamese P(8)-3 rotaviruses were generally very similar to Malawian strains, including the prototype OP354 strain. The numerical severity scores of diarrhoeal disease caused by the Vietnamese P(8)-3 rotaviruses were statistically higher than those of diarrhoeal disease caused by rotaviruses in the more common P(8)-2 lineage. Sequence and phylogenetic analysis of the VP4 gene of a Vietnamese G9P(19) rotavirus isolate showed a high degree of homology with the cognate genes of other human and porcine rotaviruses, including the prototype 4F strain.

Interacting antiferromagnetic droplets in quantum critical CeCoIn5.

The heavy fermion superconductor CeCoIn5 can be tuned between superconducting and antiferromagnetic ground states by hole doping with Cd. Nuclear magnetic resonance data indicate that these two orders coexist microscopically with an ordered moment approximately 0.7 microB. As the ground state evolves, there is no change in the low-frequency spin dynamics in the disordered state. These results suggest that the magnetism emerges locally in the vicinity of the Cd dopants.

Reversible tuning of the heavy-fermion ground state in CeCoIn5.

Cadmium doping the heavy-fermion superconductor CeCoIn(5) at the percent level acts as an electronic tuning agent, sensitively shifting the balance between superconductivity and antiferromagnetism and opening new ambient-pressure phase space in the study of heavy-fermion ground states.

Androgen regulation of signaling pathways in late fetal mouse lung development.

During lung development there is tension between positive and negative regulators of fibroblast-epithelial communication controlling type II cell differentiation. A clinical consequence of imbalance of this tension is the increased risk for respiratory distress syndrome in male infants. We hypothesized that chronic intrauterine androgen exposure alters fetal lung fibroblast maturation by down-regulating epidermal growth factor receptor (EGF-R) activity and by up-regulating transforming growth factor-beta receptor (TGFbeta-R) activity, leading to an inhibition of surfactant protein B (SP-B) and -C (SP-C) gene expression in type II cells. We treated pregnant mice with dihydrotestosterone (DHT; 2 mg/day) or vehicle for 7 days, starting on gestational day 11. On day 18, EGF binding, EGF-R phosphorylation, TGFbeta-R binding, and TGFbeta1-induced cell proliferation were studied in sex-specific fibroblast cultures. SP-B and -C messenger RNA levels were measured in whole lungs. Chronic DHT treatment reduced both EGF binding (females to 78+/-8% and males to 65+/-9% of controls) and EGF-induced EGF-R phosphorylation. TGFbeta-R binding was increased (females to 173+/-39% and males to 280+/-64% of controls), and TGFbeta-induced cell proliferation was increased in female cells (231+/-57% of controls). SP-B and -C messenger RNA expression was reduced to 55+/-10% and 75+/-4%, respectively. We conclude that chronic DHT exposure beginning early in lung development alters the balance of growth factor signaling that regulates lung maturation.

Expression of aquaporin-4 water channels in rat cholangiocytes.

We recently reported that secretin induces the exocytic insertion of functional aquaporin-1 water channels (AQP1) into the apical membrane of cholangiocytes and proposed that this was a key process in ductal bile secretion. Because AQP1 is present on the basolateral cholangiocyte membrane in low amounts, we hypothesized that another AQP must be expressed at this domain to facilitate transbasolateral water movement. Thus, we investigated the expression, subcellular localization, possible regulation by secretin, and functional activity of AQP4, a mercury-insensitive water channel expressed in other fluid transporting epithelia. Using reverse transcription-polymerase chain reaction (RT-PCR) on RNA prepared from purified rat cholangiocytes, we amplified a product of 311 bp that was 100% homologous to the reported AQP4 sequence. RNase protection assay confirmed the presence of an appropriate size transcript for AQP4 in cholangiocytes. Immunoblotting detected a band of approximately 31 kd corresponding to AQP4 in basolateral but not apical membranes of cholangiocytes. Secretin did not alter the amount of plasma membrane AQP4 but, as expected, induced AQP1 redistribution from intracellular to apical plasma membranes. Functional studies showed that AQP4 accounts for about 15% of total cholangiocyte membrane water permeability. Our results indicate that: (1) cholangiocytes express AQP4 messenger RNA (mRNA) and protein and (2) in contrast to AQP1, which is targeted to the apical cholangiocyte membrane by secretin, AQP4 is constitutively expressed on the basolateral cholangiocyte membrane and is secretin unresponsive. The data suggest that AQP4 facilitates the basolateral transport of water in cholangiocytes, a process that could be relevant to ductal bile formation.

Secretin induces the apical insertion of aquaporin-1 water channels in rat cholangiocytes.

Aquaporin-1 (AQP1) water channels are present in the apical and basolateral plasma membrane domains of bile duct epithelial cells, or cholangiocytes, and mediate the transport of water in these cells. We previously reported that secretin, a hormone known to stimulate ductal bile secretion, increases cholangiocyte osmotic water permeability and stimulates the redistribution of AQP1 from an intracellular vesicular pool to the cholangiocyte plasma membrane. Nevertheless, the target plasma membrane domain (i.e., basolateral or apical) for secretin-regulated trafficking of AQP1 in cholangiocytes is unknown, as is the functional significance of this process for the secretion of ductal bile. In this study, we used primarily an in vivo model (i.e., rats with cholangiocyte hyperplasia induced by bile duct ligation) to address these issues. AQP1 was quantitated by immunoblotting in apical and basolateral plasma membranes prepared from cholangiocytes isolated from rats 20 min after intravenous infusion of secretin. Secretin increased bile flow (78%, P < 0.01) as well as the amount of AQP1 in the apical cholangiocyte plasma membrane (127%, P < 0.05). In contrast, the amount of AQP1 in the basolateral cholangiocyte membrane and the specific activity of an apical cholangiocyte marker enzyme (i.e., gamma-glutamyltranspeptidase) were unaffected by secretin. Similar observations were made when freshly isolated cholangiocytes were directly exposed to secretin. Immunohistochemistry for AQP1 in liver sections from secretin-treated rats showed intensified staining at the apical region of cholangiocytes. Pretreatment of rats with colchicine (but not with its inactive analog beta-lumicolchicine) inhibited both the increases of AQP1 in the cholangiocyte plasma membrane (94%, P < 0.05) and the bile flow induced by secretin (54%, P < 0.05). Our results in vivo indicate that secretin induces the microtubule-dependent insertion of AQP1 exclusively into the secretory pole (i.e., apical membrane domain) of rat cholangiocytes, a process that likely accounts for the ability of secretin to stimulate ductal bile secretion.

The potential contribution of the polymerase chain reaction to the diagnosis of tuberculous meningitis.

OBJECTIVE: To examine diagnostic utility of polymerase chain reaction (PCR) on cerebrospinal fluid (CSF) in tuberculous meningitis (TBM). DESIGN: Comparison study. SETTING: Referral center for tuberculosis diagnosis and treatment in Ho Chi Minh City, Vietnam, and research laboratory in Amsterdam, the Netherlands. PATIENTS: One hundred thirty-six consecutive patients, aged 4 months to 85 years, with features compatible with TBM seen during a 12-month period. MEASUREMENTS: Clinical examination; cytology; Gram, india ink, and Ziehl-Neelsen staining; culture of CSF for bacteria, mycobacteria, fungi, and viruses; and CSF chloride, protein, and glucose. All these tests were performed in Vietnam. The PCR on CSF was performed in the Netherlands. RESULTS: Patients were managed in Vietnam without knowledge of PCR results. Based on clinical grounds and the results of initial CSF microscopy, antituberculous treatment was given to 104 patients, 66 of whom had evidence of extraneural tuberculosis. Among the 39 patients with confirmed TBM (ie, positive Ziehl-Neelsen staining or culture or PCR results for Mycobacterium tuberculosis), PCR detected 32 patients (82%), 1 case was proven positive through microscopy and 17 (44%) had positive culture results. There were no false-positive PCR results. In 99 patients with a final diagnosis of confirmed or probable TBM (ie, clinical features of TBM and response to antituberculous treatment), PCR had a sensitivity of 32%; culture, 17% and microscopy, 1%. CONCLUSIONS: Many patients who respond to treatment for TBM do not have M tuberculosis in the CSF identifiable by microscopy, PCR, or culture. Polymerase chain reaction on CSF is the best method for the laboratory diagnosis of TBM. Polymerase chain reaction is especially useful for the early diagnosis of TBM in those without active extraneural tuberculosis.

Somatostatin inhibits secretin-induced ductal hypercholeresis and exocytosis by cholangiocytes.

Previous work from our laboratory has implicated hormone-induced plasma membrane movement (i.e., endo- and exocytosis) in water and electrolyte transport by the epithelial cells that line the ducts in the liver (i.e., cholangiocytes). To further explore the cellular mechanisms regulating ductal bile secretion, we infused somatostatin and/or secretin intravenously into rats 2 wk after either bile duct ligation (BDL), a procedure that induces selective proliferation of cholangiocytes, or sham surgery and measured bile flow and biliary constituents. We also determined the effect of somatostatin on basal and secretin-induced exocytosis by purified cholangiocytes isolated from rat liver after BDL. Finally, we studied the expression of the somatostatin receptor gene by both ribonuclease (RNase) protection and nuclear run-on assays using cDNA encoding for two subtypes of the somatostatin receptor gene (i.e., SSTR1 and SSTR2). In vivo, somatostatin infusion caused a dose-dependent bicarbonate-poor decrease (57% maximal decrease below baseline; P < 0.05) in bile flow in BDL but not in sham-operated rats; in contrast, secretin caused a dose-dependent bicarbonate-rich choleresis (228% maximal increase above baseline; P < 0.05) in BDL but not in sham-operated rats. Simultaneous or prior infusion of somatostatin inhibited the secretin-induced hypercholeresis in BDL rats. In vitro, somatostatin had no effect on basal exocytosis by cholangiocytes isolated from BDL rats; however, somatostatin inhitibed (88% maximal inhibition; P < 0.05) secretin-induced exocytosis by cholangiocytes in a dose-dependent fashion. In addition, somatostatin inhibited secretin-induced increases in levels of adenosine 3',5'-cyclic monophosphate (cAMP) in cholangiocytes isolated from BDL rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Upregulation of secretin receptor gene expression in rat cholangiocytes after bile duct ligation.

Secretion stimulates ductular bile secretion by binding to receptors on intrahepatic bile duct epithelial cells (i.e., cholangiocytes). In the rat, this choleretic effect increases after bile duct ligation (BDL). Although cholangiocyte proliferation induced by BDL contributes to secretin-induced hypercholeresis, the mechanisms modulating these alterations in secretin-induced ductular bile secretion are obscure. Thus we studied the expression of secretin receptor mRNA (SR-mRNA) in purified liver cells from normal and BDL rats. Northern blot analysis and RNase protection assays with mRNA from purified liver cells demonstrated SR-mRNA only in cholangiocytes; moreover, SR gene expression showed a seven- to ninefold increase in individual cholangiocytes from BDL rats compared with controls. This increase in SR-mRNA expression was related to a similar increase in the rate of transcription of SR-mRNA in cholangiocytes from BDL rats. Thus our studies indicate that 1) SR-mRNA is detected in liver only in cholangiocytes; 2) BDL causes an increase in SR-mRNA in individual cholangiocytes; and 3) the increase in SR-mRNA after BDL is partly related to an increase in the rate of transcription of SR-mRNA by cholangiocytes after BDL. Our data suggest that upregulation of the SR gene may contribute to secretin-induced hypercholeresis.