Usefulness of linked DNA probes for prenatal diagnosis of cystic fibrosis: report of a case in a 1:4 risk pregnancy

Prenatal diagnosis of cystic fibrosis was performed with linked DNA probes in a couple with a 1:4 risk. The limits and the future of molecular prenatal diagnosis are discussed.     

Cytogenetic and molecular investigations of an abnormal Y chromosome: evidence for a pseudo-dicentric (Yq) isochromosome.

A derivative Y chromosome was found in a 55-year-old man with Lambert-Eaton paraneoplasic pseudomyastheniform disease. Small testicles, azoospermia were noticed and hormonal level values were as in the Klinefelter syndrome. A 45,X/46,XYp+ mosa?cism was described on peripheral blood lymphocytes. Cytogenetic investigations with R-G-C- and Q-banding have been performed. In situ hybridization with the GMGY 10 DNA probe showed two copies of proximal Yp sequences. Southern blot analyses were performed using the Y DNA probes 27a, 47z, 64a7, 50f2 disclosing specific Yp and Yq sequences from the pseudoautosomal boundary to the Yq proximal portion. The der(Y) has been defined as a dicentric isochromosome for the long arm with one active and one apparently suppressed centromere. The breakpoint leading to the der(Y), has been located in the pairing segment of the Y short arm (i.e. Yp11.32). So the der(Y) was interpreted as a psu dic(Y) (qter-->cen-->p11.32 ::p11.32-->qter). There was thus an almost complete duplication of the Y chromosome.     

Inferring landscape resistance to gene flow when genetic drift is spatially heterogeneous

In connectivity models, land cover types are assigned cost values characterizing their resistance to species movements. Landscape genetic methods infer these values from the relationship between genetic differentiation and cost distances. The spatial heterogeneity of population sizes, and consequently genetic drift, is rarely included in this inference although it influences genetic differentiation. Similarly, migration rates and population spatial distributions potentially influence this inference. Here, we assessed the reliability of cost value inference under several migration rates, population spatial patterns and degrees of population size heterogeneity. Additionally, we assessed whether considering intra-population variables, here using gravity models, improved the inference when drift is spatially heterogeneous. We simulated several gene flow intensities between populations with varying local sizes and spatial distributions. We then fit gravity models of genetic distances as a function of (i) the ‘true’ cost distances driving simulations or alternative cost distances, and (ii) intra-population variables (population sizes, patch areas). We determined the conditions making the identification of the ‘true’ costs possible and assessed the contribution of intra-population variables to this objective. Overall, the inference ranked cost scenarios reliably in terms of similarity with the ‘true’ scenario (cost distance Mantel correlations), but this ‘true’ scenario rarely provided the best model goodness of fit. Ranking inaccuracies and failures to identify the ‘true’ scenario were more pronounced when migration was very restricted (<4 dispersal events/generation), population sizes were most heterogeneous and some populations were spatially aggregated. In these situations, considering intra-population variables helps identify cost scenarios reliably, thereby improving cost value inference from genetic data.     

Multiple effects of temperature,photoperiod and food quality on the performance of a pine sawfly

相似文献   

Interstitial deletion of chromosome 15: two cases

Summary Two cases of interstitial deletion of chromosome 15 with similar clinical features are presented. In one case, assay of hexosaminidase A enabled us to confirm that the structural gene is located between 15q22 and 15q25 and that it is included in the deletion.     

Proof-of-concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentin

There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs.     

Industrial microbiology of solar salt production

Solar salterns can be modeled as giant outdoor chemostats, much like a series of dams on a slow-moving river. Microorganisms and their products play an essential, but sometimes uncharacterized, role in salt production in these ponds, from seawater salinity up through NaCl saturation. They may physically affect the evaporation process and their by-products may chemically modify or bind with dissolved ions. Many solar salt facilities engage microbiologists to establish monitoring programs for analyses of nutrients, standing crop and associated biological variables in the ponds. Other solar salt companies engage microbiologists only when there are “crises” in the ponds that interfere with salt production. Journal of Industrial Microbiology & Biotechnology (2002) 28, 42–47 DOI: 10.1038/sj/jim/7000173 Received 20 May 2001/ Accepted in revised form 13 June 2001