Evaluation of quantitative PCR and branched-chain DNA assay for detection of hepatitis B virus DNA in sera from hepatocellular carcinoma and liver transplant patients

This study evaluated the applicability of quantitative PCR (Q-PCR) and branched-chain DNA assays for detection of hepatitis B virus (HBV) DNA in sera. For 42 samples, the detection rates were 81 and 41%, respectively, with a correlation coefficient of 0.633. The Q-PCR is useful for early monitoring of HBV load in high-risk patients.     

MR imaging of posteromedial and posterolateral stabilisers of the knee: anatomic basis and patterns of lesions in knee injuries

Summary The angular points are the ligamentous and tendinous structures that reinforce the posteromedial and posterolateral capsule of the knee and share in fixation of the posterior horns of the menisci. They are often damaged in acute injuries and this is usually associated with ruptures of the cruciate and collateral ligaments and may add to the degree of laxity. We describe the normal appearance of these structures in terms of the sectional anatomy, correlated with the lesional appearances of complete and incomplete ruptures and associated meniscal detachments as shown by clinical testing and arthrotomy findings.

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IRM des points d'angle du genou : bases anatomiques et applications aux genoux traumatiques

Résumé Les points d'angle sont des structures ligamentaires et tendineuses qui renforcent la capsule postéro-médiale et postéro-latérale et participent à la fixation des cornes postérieures des ménisques. Leurs lésions, fréquentes au cours des traumatismes aigus, sont généralement associées à des ruptures des ligaments croisés et des ligaments collatéraux et peuvent être source d'une aggravation de la laxité. Nous rapportons, en corrélation avec l'anatomie en coupe, l'aspect normal de ces structures, et en corrélation avec les données de l'arthrotomie et du testing les aspects lésionnels observés au cours des traumatismes : ruptures complètes, incomplètes et désinsertions méniscales associées.

     

Differentiation of Rhizomucor species on the basis of their different sensitivities to lovastatin

The opportunistic pathogens Rhizomucor pusillus and Rhizomucor miehei may be agents of frequently fatal mycotic diseases. In the present study, the susceptibilities of 27 clinical and environmental isolates of R. miehei and R. pusillus to lovastatin under different culturing conditions were investigated. Most of the R. miehei strains grew at lovastatin concentrations as high as 64 to 128 microg/ml. In contrast, the inhibitory effect of lovastatin on all of the R. pusillus strains was evident at lovastatin concentrations as low as 1 to 2 microg/ml. A simple and reliable method for species-level differentiation, based on the significantly higher sensitivity of R. pusillus to lovastatin than that of R. miehei, was elaborated. According this, on malt extract agar containing 6 mug of lovastatin/ml, R. pusillus is not able to produce colonies, while R. miehei will form compact colonies.     

Transient expression of keratin 19 is induced in originally negative interfollicular epidermal cells by adhesion of suspended cells

Keratin 19 and nuclear reactivity to an endogenous lectin, galectin-1, represent a potential marker of epidermal stem cells. We detected expression of keratin 19 and nuclear binding sites for galectin-1 in adult cells migrating from the hair follicle, where cells expressing keratin 19 are located in the bulge region. The results were compared with the expression of both markers in cells adhering from suspension prepared from the interfollicular epidermis without keratin-19-positive cells and with nuclear binding sites for galectin-1. The results were compared with data from basal cell carcinomas. All cells were analyzed concerning size, as it is known that cell diameter influences the clonogenic potential of keratinocytes. The major result of this study is the observation of transient expression of keratin 19 and nuclear galectin-1 binding sites in originally negative interfollicular epidermal cells induced by adhesion. These cells were very small in size, similar to basal cells of the interfollicular epidermis or the bulge region of the hair follicle. The influence of the suspension regimen on beta1-integrin expression, cell diameter and growth was also monitored. A population of cells highly positive for beta1 integrin of the same diameter as keratin-19-positive cells insensitive to induction of terminal differentiation by lack of anchorage was characterized. Cells of the same size were also observed in the keratin-19-positive cells of basal cell carcinomas. In conclusion, the expression of poor levels of differentiation induced by cell adhesion is transient. Also, keratin 19 expression should not be exclusively regarded as a marker of stem cell activity.     

Apoptotic cell death in mouse models of GM2 gangliosidosis and observations on human Tay-Sachs and Sandhoff diseases

Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative diseases resulting from the inability to catabolize GM2 ganglioside by beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit (Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B (beta beta homodimer) is also defective in Sandhoff disease. We previously developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs) mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff) mice succumb to a profound neurodegenerative disease by 4-6 months of age. Here we find that neuron death in Hexb-/- mice is associated with apoptosis occurring throughout the CNS, while Hexa-/- mice were minimally involved at the same age. Studies of autopsy samples of brain and spinal cord from human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances, in keeping with the severe expression of both diseases. We suggest that neuron death is caused by unscheduled apoptosis, implicating accumulated GM2 ganglioside or a derivative in triggering of the apoptotic cascade.      

The role of recombination signal sequences in the preferential joining by deletion in DH-JH recombination and in the ordered rearrangement of the IgH locus

The bias favoring deletion over inversion in DH-JH rearrangement has been known for years, but the underlying mechanism has yet to be fully defined. It has been suggested that the ratio of deletion/inversion is determined by the combined effect of two factors: (i) the relative strengths of 5' and 3' recombination signal sequences (RSS) of a DH segment, and (ii) the efficiency with which the deletional product (one joint) forms relative to the inversional product (two joints). In this study, we analyzed for the first time the effect of factor 1 alone on the biased 3' RSS utilization in DH-JH joining by using deletional plasmids in an extrachromosomal substrate V(D)J recombination assay. It was found that the 3' RSS and associated coding end (12 bp) mediate recombination more efficiently than the 5' RSS/coding end DH-JH plasmids. These results demonstrate that the effect of the RSS/coding end alone can account, at least partially, for the predominant deletion in DH-JH recombination. The potential effect of the relative strength of RSS and associated coding end on the ordered rearrangement of DH-JH followed by VH to DH-JH was also assessed. When recombination frequencies of D-->J (3' DH to J3) were compared with frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found that V-->D joining was, if anything, more efficient than D-->J joining. Therefore, if all three segments were accessible, RSS/coding end effects would not contribute to the ordered rearrangement of the IgH locus.      

Mechanisms of enhanced prevalence of asthma and atopy in developed countries

Atopy — a T helper 2 cell driven hypersensitivity to innocuous antigens (allergens) which causes most cases of asthma — is of complex genetic and environmental origins. There is compelling epidemiological evidence for a rise in atopic disease in ‘westernised’ communities. The changing pattern of microbial exposure in early childhood is suggested to be the principal candidate mechanism for this rise.