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.      

Sex Differences in Rats in the Development of and Recovery From Ethanol Dependence Assessed by Changes in Seizure Susceptibility

BACKGROUND: Previous investigations have found sex differences in rats in response to chronic ethanol exposure. The most dramatic differences were observed with anticonvulsant treatment during ethanol withdrawal, when seizure susceptibility is significantly increased. Sex differences in this response were found for both GABAergic and glutamatergic compounds. This study was aimed at exploring whether sex also influences the timing for the development of and recovery from ethanol dependence. METHODS: Ethanol was administered in a liquid diet, with pair-fed animals receiving dextrose, substituted isocalorically for the ethanol. Ethanol dependence and withdrawal were assessed by measurement of seizure thresholds after abrupt removal of the ethanol diet. Seizure thresholds were determined by slow, tail vein infusion of the gamma-aminobutyric acidA-receptor antagonist bicuculline. RESULTS: Male and female rats displayed differences in timing for both onset and recovery from ethanol dependence, as determined by changes in ethanol withdrawal seizure susceptibility. Female rats were slower to develop dependence and quicker to recover compared with male rats. Furthermore, acute ethanol administration did not alter seizure susceptibility in pair-fed control animals, but it was anticonvulsant in ethanol-withdrawn rats. Ethanol-withdrawn female rats showed a greater response to acute ethanol administration than did male rats. CONCLUSIONS: This set of experiments uncovered additional sex differences in one measure of ethanol dependence and withdrawal. Proposed mechanisms for the development of ethanol dependence involve alterations in subunit assembly of gamma-aminobutyric acidA and NMDA receptors or various posttranslational modifications. In consideration of these findings, whatever mechanisms underlie the development of ethanol dependence, there is a different sequence of events in male compared with female rats. Studies are ongoing to determine associations between behavioral measures of ethanol dependence/withdrawal and selective neuronal adaptations.     

A-V block in accidental hypothermia

His bundle electrocardiography was performed on a patient with accidental hypothermia on whom the standard electrocardiogram (ECG) showed absent P waves, prominent J waves and a slightly irregular rhythm. Sino-ventricular conduction and a prolonged AH interval not responsive to atropine were found. These abnormalities reversed with rewarming.     

Significance and treatment of nocturnal angina preceding myocardial infarction.

The presence of nocturnal angina and congestive heart failure within the month prior to admission was evaluated in the 174 patients with acute myocardial infarction. Heart size was evaluated radiographically at the time of admission. Twenty-three patients (13 per cent) experienced nocturnal angina. The incidence of nocturnal angina was significantly higher in those with anterior myocardial infarction (p less than 0.005) and subendocardial infarction (p less than 0.02) when compared with patients with inferior MI. Congestive heart failure was more common prior to admission in those with nocturnal angina (9/23) as opposed to those without (3/141) (p less than 0.001). Cardiomegaly was seen in 9/23 patients with nocturnal angina and 22/141 without (p less than 0.02). We conclude that the presence of nocturnal angina in those who develop MI increases the likelihood that the infarction will be either anterior or subendocardial rather than inferior. The association of nocturnal angina and congestive heart failure to anterior myocardial infarction is probably due to more severe and probably significant left coronary artery disease.     

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.     

Caregiver burden and disability in somatization disorder

Objective

Authors assessed disability and caregiver burden in patients with somatization disorder (SOM-D), and compared it with that in patients with schizophrenia and chronic depression.

Methods

The sample consisted of 30 patients diagnosed as SOM-D as per ICD 10 Diagnostic Criteria for Research (ICD-10-DCR), and 30 age- and gender-matched patients each of schizophrenia and depression, who served as comparison groups. Disability and caregiver burden were assessed using WHO's Disability Assessment Schedule (WHO-DAS) and the Family Burden Assessment Schedule (FBAS) respectively. Functioning and severity of illness were assessed on the Global Assessment of Functioning scale (GAF) and Clinical Global Impression scale (CGI) respectively.

Results

Severity of illness in patients with SOM-D was comparable to that in the comparison groups. Patients with SOM-D scored higher on total disability on WHO-DAS than the patients with schizophrenia and depression, though scores on family burden were comparable. Disability in patients with SOM-D was more in females, less educated, older and those working at home, compared to the other demographic groups.

Conclusion

Patients with SOM-D suffer considerable disability due to illness and impose significant burden on their caregivers, comparable to that seen in severe mental illnesses like schizophrenia and chronic depression.     

Atrioventricular block with lidocaine therapy

A case is presented of complete atrioventricular (A-V) block occurring after a 50 mg bolus injection of lidocaine. Base-line studies before administration of lidocaine showed evidence of trifascicular block manifested by complete right bundle branch block, left anterior hemiblock and a markedly prolonged H-V interval. Advanced A-V block and then complete A-V block distal to the His bundle developed after administration of lidocaine. Lidocaine should be used with caution in patients with trifascicular disease; if it is administered to such patients, insertion of a temporary pacemaker catheter should be considered.     

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.