Identification and characterization of aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus with partial vasopressin response

Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused most often by mutations in the vasopressin V2 receptor (AVPR2). We studied a family which included a female patient with NDI with symptoms dating from infancy. The patient responded to large doses of desmopressin (dDAVP) which decreased urine volume from 10 to 4 I/day. Neither the parents nor the three sisters were polyuric. The patient was found to be a compound heterozygote for two novel recessive point mutations in the aquaporin-2 (AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is the site for inhibition of water permeation by mercurial compounds and is located near to the NPA motif conserved in all aquaporins. Osmotic water permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2 was not increased over water control, while expression of L22V cRNA increased the Pf to approximately 60% of that for wild-type AQP2. Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO cells showed that the C181W mutant had an endoplasmic reticulum-like intracellular distribution, whereas L22V and wild-type AQP2 showed endosome and plasma membrane staining. Water permeability assays showed a high Pf in cells expressing wild-type and L22V AQP2. This study indicates that AQP2 mutations can confer partially responsive NDI.      

Myocardial and circulatory effects of inosine

The action of inosine (2.5, 5, or 10 mg.kg-1.min-1 iv) was investigated in open chest rats (n = 46) and guinea pigs (n = 16). Left ventricular and aortic pressures, dP/dtmax, and stroke volume were measured. Additionally, isovolumic peak pressure and peak dP/dtmax were measured during short occlusions of the aorta for assessing myocardial performance independent of circulatory changes. In rats inosine caused a dose dependent decrease in dP/dtmax (-5%, -21%, -40% of preinfusion values), heart rate (-7%, -23%, -55%), and mean aortic pressure. Additionally, a subgroup of seven rats was paced at their initial preinfusion heart rate, but independently from the heart rate there was a reduction in dP/dtmax (-15%). The isovolumic measurements confirmed the negative inotropic effect of inosine in rats. Peak dP/dtmax was reduced to 85% of preinfusion values with a dose of 2.5 mg.kg-1 min-1 (to 70% of preinfusion values with 10 mg.kg-1.min-1). Similarly, the maximum isovolumic pressure for a defined filling volume was decreased by 30 mmHg (at 350 microliter; 5 mg.kg-1.min-1; p less than 0.05). The mean aortic pressure decreased with 2.5 mg.kg-1.min-1 inosine indicating vasodilative properties. In contrast to the significant effects in rats even 10 mg.kg-1.min-1 inosine did not have an effect on heart rate, mean aortic pressure, or dP/dtmax in guinea pigs. The isovolumic peak left ventricular pressure in guinea pigs was also unchanged after inosine infusion. Thus the haemodynamic effects of inosine were species dependent.     

ATG16L1 and NOD2 polymorphisms enhance phagocytosis in monocytes of Crohn’s disease patients

AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.     

Evaluation of Efficacy of Microwave Irradiation in Disinfecting Dental Gypsum Casts: An Ex Vivo Study

The aim of this study is to assess the efficacy of microwave irradiation in disinfecting gypsum casts and also to compare its efficacy with validated method of chemical disinfection. The present study is an ex vivo study conducted on a sample of five irreversible hydrocolloid impressions in vitro and on ten patients gypsum casts in vivo following standard impression techniques to check the efficacy of microwave oven irradiation and compare its efficacy with standard chemical method of disinfection. Results were analysed using Mann–Whitney test and Wilcoxon signed rank test. Untreated gypsum casts showed cfu/ml counts with a median log value of 6, while microwave-irradiated ones had median cfu/ml counts of 0. Casts poured from chemically disinfected impressions demonstrated cfu/ml counts with a median log value of 5. Microwave irradiation was found to be effective in disinfecting gypsum casts when compared to chemical disinfectant in disinfecting dental impressions.     

Children with ADHD and motor dysfunction compared with children with ADHD only

The purpose of this study was to identify group differences in children with attention-deficit-hyperactivity disorder and motor dysfunction (ADHD-MD) and ADHD only, and to evaluate the medication responsiveness of ADHD-MD. Sixty-three children (49 males and 14 females; mean age 9 years 10 months, SD 2 years 10 months) underwent a triple blind, placebo-controlled crossover study evaluating two dose levels of methylphenidate (0.3 mg/kg and 0.5 mg/kg [corrected], twice daily) and placebo. Forty-nine trials were completed. Nineteen were children with ADHD-MD, 44 had ADHD only. Behavior and functioning were assessed at home and at school. Treatment effects were assessed using the Abbreviated Symptom Questionnaire for Parents and Teachers. Children with ADHD-MD were more likely to have severe ADHD-combined type and other neurodevelopmental and behavioral problems. Both groups of children had a linear dose response to medication (placebo, low, high) and there was no evidence of a group by dose interaction or an overall group effect at home or school. The lack of group effect suggests that these children responded to medication like the other subgroups.