BDNF–TrkB signaling in the nucleus accumbens shell of mice has key role in methamphetamine withdrawal symptoms

Depression is a core symptom of methamphetamine (METH) withdrawal during the first several weeks of abstinence. However, the precise mechanisms underlying METH withdrawal symptoms remain unknown. Brain-derived neurotrophic factor (BDNF) and its specific receptor, tropomyosin-related kinase (TrkB), have a role the in pathophysiology of depression. In this study, we examined the role of BDNF–TrkB signaling in different brain regions of male mice with METH withdrawal symptoms. Repeated METH (3 mg kg⁻¹ per day for 5 days) administration to mice caused a long-lasting depression-like behavior including anhedonia. Western blot analysis showed that BDNF levels in the nucleus accumbens (NAc) of METH-treated mice were significantly higher than those of control mice whereas BDNF levels in other regions, including the prefrontal cortex and hippocampus, were not altered. METH-induced depression-like behavior, behavioral sensitization and dendritic changes in the NAc shell were improved by subsequent subchronic administration of TrkB antagonist ANA-12 (0.5 mg kg⁻¹ per day for 14 days), but not TrkB agonist 7,8-dihydroxyflavone (10 mg kg⁻¹ per day for 14 days). In vivo microdialysis showed that METH (1 mg kg⁻¹)-induced dopamine release in NAc shell of METH-treated mice was attenuated after subsequent subchronic ANA-12 administration. Interestingly, a single bilateral infusion of ANA-12 into the NAc shell, but not NAc core, showed a rapid and long-lasting therapeutic effect. However, ketamine and paroxetine had no effect. These findings suggest that increased BDNF–TrkB signaling in the NAc shell has an important role in the behavioral abnormalities after withdrawal from repeated METH administration, and that TrkB antagonists are potential therapeutic drugs for withdrawal symptoms in METH abusers.     

DEGS2 polymorphism associated with cognition in schizophrenia is associated with gene expression in brain

A genome-wide association study of cognitive deficits in patients with schizophrenia in Japan found association with a missense genetic variant (rs7157599, Asn8Ser) in the delta(4)-desaturase, sphingolipid 2 (DEGS2) gene. A replication analysis using Caucasian samples showed a directionally consistent trend for cognitive association of a proxy single-nucleotide polymorphism (SNP), rs3783332. Although the DEGS2 gene is expressed in human brain, it is unknown how DEGS2 expression varies during human life and whether it is affected by psychiatric disorders and genetic variants. To address these questions, we examined DEGS2 messenger RNA using next-generation sequencing in postmortem dorsolateral prefrontal cortical tissue from a total of 418 Caucasian samples including patients with schizophrenia, bipolar disorder and major depressive disorder. DEGS2 is expressed at very low levels prenatally and increases gradually from birth to adolescence and consistently expressed across adulthood. Rs3783332 genotype was significantly associated with the expression across all subjects (F_3,348=10.79, P=1.12 × 10⁻³), particularly in control subjects (F_1,87=13.14, P=4.86 × 10⁻⁴). Similar results were found with rs715799 genotype. The carriers of the risk-associated minor allele at both loci showed significantly lower expression compared with subjects homozygous for the non-risk major allele and this was a consistent finding across all diagnostic groups. DEGS2 expression showed no association with diagnostic status after correcting for multiple testing (P>0.05). Our findings demonstrate that a SNP showing genome-wide association study significant association with cognition in schizophrenia is also associated with regulation of DEGS2 expression, implicating a molecular mechanism for the clinical association.     

Impaired glucose tolerance and reduced beta-cell function in overweight Latino children with a positive family history for type 2 diabetes

The objective of this study was to examine relationships between impaired glucose tolerance (IGT) and body composition and insulin-related phenotypes in 150 overweight Latino children with a family history of type 2 diabetes. Glucose tolerance was assessed by an oral glucose challenge. Body composition was assessed by dual energy x-ray absorptiometry and magnetic resonance imaging. Insulin sensitivity, the acute insulin response, and the disposition index (DI), as an index of beta-cell function, were determined by an iv glucose tolerance test and compared between normal glucose-tolerant and IGT children. IGT was present in 28% of children, and was similar across obesity groups, but higher in children exposed to gestational diabetes mellitus (41% IGT). There were no significant differences in body composition, fat distribution, insulin sensitivity, or acute insulin response, but DI was significantly lower in IGT children by 16% (P < 0.02), and DI was inversely related to age. In conclusion, IGT is present in 28% of overweight Latino children with a family history of type 2 diabetes, is not influenced by obesity, is more prevalent in children exposed to gestational diabetes mellitus, and is related to poor beta-cell function, which shows signs of deterioration with age in this population.     

Complete genome sequence of an M1 strain of Streptococcus pyogenes

The 1,852,442-bp sequence of an M1 strain of Streptococcus pyogenes, a Gram-positive pathogen, has been determined and contains 1,752 predicted protein-encoding genes. Approximately one-third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of human disease than any other bacterial species, more than 40 putative virulence-associated genes have been identified. Additional genes have been identified that encode proteins likely associated with microbial "molecular mimicry" of host characteristics and involved in rheumatic fever or acute glomerulonephritis. The complete or partial sequence of four different bacteriophage genomes is also present, with each containing genes for one or more previously undiscovered superantigen-like proteins. These prophage-associated genes encode at least six potential virulence factors, emphasizing the importance of bacteriophages in horizontal gene transfer and a possible mechanism for generating new strains with increased pathogenic potential.     

The subunits of activator 1 (replication factor C) carry out multiple functions essential for proliferating-cell nuclear antigen-dependent DNA synthesis.

p37 and p40 are two cloned gene products of the five-subunit human cellular DNA replication factor activator 1 (A1) protein complex (also called replication factor C). Here, we describe the solubilization, purification, and characterization of these two proteins that were overproduced in Escherichia coli. Using a nitrocellulose filter binding assay, we demonstrated that the purified A1 p37 protein associated with DNA preferentially at the primer terminus, a property resembling that of the A1 complex. We also show that in the presence of relatively high levels of salt, the recombinant p37 protein alone activated DNA polymerase epsilon but not polymerase delta in catalyzing the elongation of DNA chains. The p40 protein specifically associated with cellular p37 and proliferating-cell nuclear antigen (PCNA) present in HeLa cell cytosolic extract. The addition of purified p40 protein abolished the in vitro polymerase delta-catalyzed DNA elongation reaction dependent on both PCNA and A1. However, this inhibition was reversed by excess polymerase delta, suggesting a specific interaction between the polymerase and the p40 protein. Thus, while p37 binds DNA at the primer end and has a specific affinity for pol epsilon, p40, which binds ATP, interacts with PCNA and pol delta. These activities are essential for the DNA elongation reactions that lead to the synthesis of leading-strand DNA and the maturation of Okazaki fragments.     

Increased identification of the primary care provider as the main source of asthma care among urban minority children

Objective: Urban, minority, and disadvantaged youth with asthma frequently use emergency departments (EDs) for episodic asthma care instead of their primary care providers (PCPs). We sought to increase the rate of guardians' identification of the PCP as the source of asthma care for their children through integrated electronic health records and care coordination. Methods: In this prospective cohort study, we implemented an electronic communication process between an asthma specialty clinic and PCPs coupled with short-term care coordination in sample of youth aged 2–12 years with asthma and surveyed their guardians at baseline and 3 and 6 months after the intervention. Results: Guardians of 50 children (median age 5.8 years, 64% male, 98% African American, 94% public insurance) were enrolled. Compared to baseline, at 3 and 6 months after the intervention, significantly more guardians reported that the PCP was their child's primary asthma health care provider [70% at baseline, 85% at 3 months, 83% at 6 months (time averaged adjusted OR 77.4, 95% CI 3.0, 2027.1]. Further, significantly more guardians reported that they took their child to the PCP when the child experienced problems with his/her asthma [16% at baseline, 35% at 3 months, 41% at 6 months (time averaged adjusted odds ratio (OR) 10.6, 95% CI 2.7, 41.7]. Conclusion: Care in a subspecialty asthma clinic augmented by electronic communication with PCPs and short term care coordination was associated with significantly improved identification of PCPs as the primary source of asthma care in a cohort of urban minority youth.     

Effects of autogenous reinfusion of ascitic fluid on plasma atrial natriuretic peptide and renin activity in cirrhotic patients]

Acute volume loading produced by autogenous reinfusion of ascitic fluid provides an ideal volume expansion model for studying hormonal regulation and it was carried out in 10 cirrhotic patients with massive ascites. The basal plasma ANP level in the cirrhotic patients with ascites was 1776.00 +/- 160.72 ng/L, which was significantly elevated as compared with the level in normal controls (378.36 +/- 39.58 ng/L, P less than 0.01), PRA was significantly higher in patients with ascites (5.13 +/- 0.18 micrograms/l/h) than in healthy volunteers (1.46 +/- 0.31 micrograms/l/h, P less than 0.01). During reinfusion of ascitic fluid there was a significant natriuresis and diuresis; ANP rose from a basal mean value to a peak value of 2166.00 +/- 195.70 ng/l (P less than 0.05) at periinfusion. Subsequently, ANP dropped at 1 hour after infusion (1819.00 +/- 165.92ng/L, P less than 0.05), PRA dropped progressively from a mean basal level to that of 2.48 +/- 0.58 micrograms/l/h (P less than 0.05) at periinfusion. These data demonstrate that there is no evidence for absolute deficiency of ANP in cirrhosis with ascites. The immediate diuresis and natriuresis were associated with a rise in ANP, but the sustained renal consequences may be possibly connected with suppression of RAAS.     

Inducible proteins binding to the murine thymidine kinase promoter in late G1/S phase.

By performing DNase I footprint and band-shift analyses of a 170-base-pair region of the murine thymidine kinase promoter, we identified an inducible DNA binding activity that we named Yi. Yi binding activity was not detected in G0 and G1 extracts, but it was observed as cells crossed the G1/S boundary. Yi proteins bind specifically to a consensus sequence (CCCNCNNNCT) found at three distinct sites in this promoter region. We also observed a murine Sp1 binding activity that was constitutive throughout the cell cycle. We propose that the G1/S-specific Yi binding is important for murine thymidine kinase gene regulation and perhaps also for initiation of DNA synthesis.     

Pattern of left ventricular filling in hypertrophic cardiomyopathy: Assessment by Doppler echocardiography and radionuclide angiography

Aims The left ventricle in hypertrophic cardiomyopathy is anatomicallyand functionally non-uniform. This study was undertaken to verifywhether a heterogeneity in the pattern of diastolic fillingcan be detected along the left ventricular inflow tract in hypertrophiccardiomyopathy. Methods and results Early (E) and late (A) diastolic velocitieswere recorded by Doppler echocardiography at mitral and at mid-ventricularlevel in 16 normal volunteers and 30 patients with hypertrophiccardiomyopathy. Patients with hypertrophic cardiomyopathy alsounderwent radionuclide angiography to assess left ventricularfunction. E wave decreased significantly in normal volunteers(80±15 to 60±14cm.s^–1;P<0·001),but it increased in hypertrophic cardiomyopathy (76±22to 87±28cm.s^–1;P=0·04), whereas the A wavedecreased similarly in both. By multivariate analysis, systolicasynchrony and the ejection fraction of left ventricular lateralwall were directly related to the pattern of early filling progression(r=0·656; F=9·467;P<0·002). Moreover,systolic asynchrony showed a univariate direct correlation withchanges in E velocity (r=0·42;P=0·02). Conclusion Many patients with hypertrophic cardio-myopathy havean acceleration of filling within the left ventricular inflowtract; this phenomenon is directly related to systolic asynchronyand ejection fraction of the left ventricular lateral wall,suggesting increased suction.     

Irritable bowel syndrome: is the search for lactose intolerance justified?

OBJECTIVES: To determine if confirmation of hypolactasia offers any benefit to the dietary treatment of patients with irritable bowel syndrome (IBS). METHODS: One hundred and twenty-two consecutive IBS patients (37 male, 85 female) were given lactose hydrogen breath tests (LHBT). Those with positive LHBT followed a low lactose diet for 3 weeks. Those improving on the diet were given double-blind, placebo-controlled challenges (DBPCC) with 5 g, 10 g and 15 g of lactose and a placebo, to confirm lactose intolerance. Those who did not respond to the low lactose diet followed either an exclusion or low fibre diet. Symptoms scores were kept prior to the LHBT, 8 h post-LHBT and daily whilst following any dietary change. Patients with negative LHBT returned to clinic and subsequent dietary interventions were recorded. RESULTS: LHBT was positive in 33/122 (27%) IBS patients. Syrr otom scores prior to LHBT were not significantly different between the two groups, but after LHBT the symptoms in the positive group were significantly worse. Twenty-three patients followed a low-lactose diet of which only nine (39%) improved. Six who did not improve followed an exclusion diet, three improved and all were intolerant of milk. Three tried a low fibre diet with two improving. DBPCC were inconclusive. In the negative LHBT group 35 agreed to try a diet and 24 improved (69%). Eight were intolerant of cow's milk. CONCLUSIONS: Use of a low lactose diet was disappointing in IBS patients with lactose malabsorption. Food intolerance was demonstrated in IBS patients with positive or negative LHBT and milk was identified as a problem in both groups. DBPCC were inconclusive. There appears to be little advantage in trying to separate patients who malabsorb lactose from others with IBS.