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.      

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.     

Total Patellar Skin Loss From Cryotherapy After Total Knee Arthroplasty

The use of cryotherapy after total knee arthroplasty is a very common therapeutic adjunct accepted as routine postoperative care. We present 2 cases of total patellar skin loss due to cryotherapy after total knee arthroplasty. Substantial soft tissue defects were created after the initial debridement of the necrotic tissue. Both patients were evaluated for frostbite, and the wounds were sharply debrided. Application of an advanced wound management technique involves the use of a collagen-glycosaminoglycan biodegradable bilayer matrix, silver impregnated antimicrobial dressing, and low-pressure vacuum device, followed by delayed split thickness skin grafting and low-pressure vacuum device. We find that this technique provided durable soft tissue coverage for necrotic wounds of the knee that do not involve the joint capsule.     

Molecular characterization of African swine fever virus from outbreaks in Namibia in 2018

Five samples were collected from four suspected outbreaks of African swine fever in Namibia in 2018. Sequencing of the C‐terminus of the B646L gene (p72 protein), the central hypervariable region (CVR) of the B602L gene, the E183L gene (p54 protein) and the CD2v (used to determine the serogroup) was performed on DNA isolated from the samples. Phylogenetic analyses of the B646L (p72) revealed that one of the samples belonged to genotype I while the remaining samples could not be assigned to any currently known genotype. In contrast, by using the E183L gene three of the samples were shown to belong to genotype Id and only two were of unknown genotype. Based on the analysis of the partial CD2v amino acid sequences of four of the samples, one of the viruses clustered with serogroup 2 while the other three did not cluster within any of the eight known serogroups. Examination of the CVR identified three variants with 8, 18 and 24 tetrameric tandem repeat sequences. This study indicates that at least three different genetically distinct ASFV are currently present in Namibia.     

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.     

Bilateral subclavian steal syndrome

Background

Bilateral atherosclerotic subclavian artery occlusion is rare.

Aim

To describe the surgical treatment of a patient with symptomatic bilateral subclavian artery occlusion.

Methods

A midline sternotomy and bilateral aorto-subclavian bypass was performed in a male with upper limb, exercise-induced vertigo.

Results

Postoperatively symptomatic improvement paralleled an increase in brachial systolic arterial blood pressure readings.

Conclusion

Bypass grafting is the more durable option for subclavian artery occlusion, as angioplasty with or without stenting is associated with a higher rate of late stenosis.