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.      

Association of bacterial vaginosis with a history of second trimester miscarriage

The aim of this study was to determine whether bacterial vaginosis(BV) is associated with a history of recurrent pregnancy loss.A total of 500 consecutive patients attending the RecurrentMiscarriage Clinic were screened for the presence of BV. Inwomen who had had at least one late miscarriage BV was foundtwice as commonly (27/130; 21%) as in women who had had onlyearly losses (31/370; 8%) (P<0.001). The difference was evenlarger (26 versus 8%) if women who had had term pregnancieswere excluded. Moreover, BV was found three times more commonlyin Afro-Caribbean women [17 (29%) of 58] than in Caucasian women[36 (9%) of 379] and, in both groups of women, BV was diagnosedat least twice as frequently in those with a history of at leastone late miscarriage than in those who had experienced firsttrimester pregnancy losses only (P<0.001). The conditionoccurred twice as often among smokers than non-smokers and,in both groups, it was at least twice as common in women witha history of at least one late miscarriage as in those who hadhad early pregnancy losses only (P<0.001). However, the relationshipbetween BV and smoking was independent of ethnic origin. Womenwho douched with chloroxylenol were mostly Afro-Caribbean andhad BV more than twice as often as women who did not douche.     

The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission

Factors involved in the stability of trinucleotide repeats during transmission were studied in 139 families in which a full mutation, premutation or intermediate allele at either FRAXA or FRAXE was segregating. The transmission of alleles at FRAXA, FRAXE and four microsatellite loci were recorded for all individuals. Instability within the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for FRAXE) was extremely rare; only one example was observed, an increased in size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were unstably transmitted. Instability was more frequent for FRAXA intermediate alleles that had a tract of pure CGG greater than 37 although instability only occurred in two of 13 such transmissions: the changes observed were limited to only one or two repeats. Premutation FRAXA alleles over 100 repeats expanded to a full mutation during female transmission in 100% of cases, in agreement with other published series. There was no clear correlation between haplotype and probability of expansion of FRAXA premutations. Instability at FRAXA or FRAXE was more often observed in conjunction with a second instability at an independent locus suggesting genomic instability as a possible mechanism by which at least some FRAXA and FRAXE mutations arise.      

Quantitation of carcinogen-induced DNA damage and repair in human cells with the UVR ABC excision nuclease from Escherichia coli

Recent studies by others have shown that the endonuclease complexcoded for by the uvrA, uvrB and uvrC genes of Escherichia coli(UVR ABC excision nuclease) can incise DNA containing a varietyof ‘bulky-type’ lesions, such as those resultingfrom u.v. light, (±)-7, 8ß-dihydroxy-9, 10-epoxy-7,8, 9, 10-tetrahydrobenzo[a]pyrene (anti-BPDE), and N-acetoxy-2-acetylaminofluorene.Using partially purified UVR ABC excision nuclease, we havequantitated the number of endonuclease sensitive sites (ESS)in purified DNA isolated from human fibroblasts treated withu.v. light or BPDE. The number of ESS/10⁸ daltons of DNA werecalculated from the number average mol. wt. of the DNA as determinedby sedimentation in alkaline sucrose gradients. The number ofendonuclease sites increased linearly with increasing dosesof either u.v. light or BPDE. The UVR ABC excision nucleasewas able to incise a majority of the BPDE-DNA adducts. Xerodermapigmentosum fibroblasts, complementation group A (XP12BE) had20–25% more ESS at each dose than the BPDE-treated normal(HSBP) cells. Cells treated with 4 µM BPDE and allowed12 h of incubation to perform excision repair showed removalof 60% of the initial number of ESS from HSBP DNA and 40% ofthe ESS from XP-A DNA. Beyond 12 h XP12BE cells lost no additionalESS while HSBP cells continued to lose ESS, athough at a slowerrate, until at 48 h only 22% of the initial ESS remained. Incells treated with 10 J/m² of u.v. light, the UVR ABC excisionnuclease detected 60% of the sites recognized by the pyridiminedimer specific Micrococcus luteus glycosylase/apyrimidinic endonuclease.These results demonstrate the potential use of the UVR ABC excisionnuclease in a quantitative assay for determining the numberof carcinogen-induced lesions in human DNA.     

Factor V Leiden and recurrent miscarriage-prospective outcome of untreated pregnancies

BACKGROUND: Some cases of recurrent miscarriage and later pregnancy complications have a thrombotic basis. Factor V Leiden is a common thrombophilic mutation. METHODS: The prospective outcome of untreated pregnancies amongst 25 women heterozygous for the Factor V Leiden allele who had a history of either recurrent early miscarriages only (three or more miscarriages at <12 weeks gestation; n = 19) or of late miscarriage (>12 weeks gestation; n = 9) was studied. Control groups of women with a similar pregnancy history but who had a normal Factor V genotype were also studied. RESULTS: The live birth rate was significantly lower amongst women with a history of recurrent early miscarriage who carried the Factor V Leiden allele (6/16; 37.5%) compared with that amongst those with a normal Factor V genotype (106/153; 69.3%; odds ratio 3.75, 95% confidence intervals 1.3-10.9). The live birth rate was 11.1% (1/9) amongst those with a history of late miscarriage carrying the Factor V Leiden allele and 48.9% (22/45) amongst those with a normal Factor V genotype. CONCLUSIONS: Attention should be directed at screening women with recurrent miscarriage associated with placental thrombosis for Factor V Leiden and a policy of targeted thromboprophylaxis during future pregnancies should be assessed in the form of a randomized controlled trial.     

Assuring the quality of in-home supportive services: an evolving challenge

This article reports on the Ohio Quality Assurance Project, a two year demonstration. The project developed a model quality assurance system for in-home supportive services funded by Title III of the Older Americans Act including home health aide, personal care, homemaker, transportation and escort, home delivered meals, chore and home maintenance services. Using four planning and service areas in the state of Ohio comprising over 40 countries, the project developed, implemented and evaluated quality assurance standards and monitoring activities for Older Americans Act services. In addition, a second part of the project included in-depth case studies with consumers receiving in-home care.     

Expression of three alpha 2-adrenergic receptor subtypes in rat tissues: implications for alpha 2 receptor classification

Based on biochemical and ligand binding studies in various tissues and species, evidence for several alpha 2-adrenergic receptor subtypes has accumulated. The current alpha 2-adrenergic receptor classification (alpha 2A, alpha 2B, alpha 2C) is based exclusively on pharmacological criteria. The molecular cloning of three distinct genes for human alpha 2-adrenergic receptors has confirmed the existence of multiple alpha 2-adrenergic receptor subtypes. According to their localization on different human chromosomes, the receptor genes were termed alpha 2-C10, alpha 2-C4, and alpha 2-C2. The relationship, however, between the pharmacologically characterized alpha 2-adrenergic receptors and the isolated genes has yet to be clarified. Using Northern blot hybridization, we analyzed the expression of the three cloned alpha 2-adrenergic receptor genes in 13 rat tissues, as well as in cell lines previously described as model systems for the pharmacologically defined alpha 2-adrenergic receptor subtypes. The alpha 2-C10 receptor corresponds to the alpha 2A subtype and is expressed in rat brainstem, cerebral cortex, hippocampus, pituitary gland, cerebellum, kidney, aorta, skeletal muscle, spleen, and lung. Messenger RNA coding for the alpha 2-C4 receptor was detected only in brain regions, not in peripheral tissues, whereas the alpha 2-C2 message was found only in liver and kidney. Hybridization experiments with RNA derived from tissues and cells from which the pharmacological alpha 2-receptor classification has been developed lead to the conclusion that the alpha 2B subtype represents two distinct receptor molecules, the alpha 2-C4 and a subtype previously undetected by classical ligand binding approaches. Furthermore, our results suggest that the alpha 2C subtype characterized in opossum kidney cells is an interspecies variation of alpha 2-C4 rather than a separate subtype. Finally, the cloned alpha 2-C2 receptor was found to be "alpha 2B-like" and not covered by the current pharmacological classification.     

Histopathologic features of composite ganglioneuroblastoma. Immunohistochemical distinction of the stromal component is related to prognosis

Histopathologic features of 18 cases of composite ganglioneuroblastoma (CGNB) were studied with immunohistochemical staining techniques using antibodies against S-100 protein (S-100), ferritin (FER), and leukocytic common antigen (LCA). Cases of CGNB were divided on the basis of the morphologic features of neuroblastic elements into three prognostic subgroups: "Type A Intermixed," having individual microscopic nests of neuroblasts (N = 4, 100% survival); "Type B Intermixed," having microscopic aggregates of multiple neuroblastic nests (N = 6, 67% survival); and "Nodular," having grossly visible nodule(s) of neuroblastic proliferation (N = 8, 0% survival). Survival rates are significantly different for the prognostic subgroups (P less than 0.025). Each prognostic subgroup demonstrated an immunohistochemically distinct pattern of stromal cell composition in the neuroblastic elements: Type A Intermixed had numerous S-100 cells and no FER cells, Type B Intermixed contained many S-100 cells and a moderate number of FER cells, and Nodular had few S-100 cells with many FER cells. The S-100 and FER scores, determined by counting the positive cells through a line sampling method, differed significantly between these prognostic subgroups. Lymphocytic aggregations in tumor tissue evaluated by volumetric assessment with LCA staining, on the other hand, showed no contribution in predicting the outcome of the patients. There was also an inverse relationship between S-100 and FER score, suggesting a relationship between the relative predominance of these stromal cell types, tumor histopathologic features, and the biologic behavior of CGNB.