Amperometric alcohol electrode with extended linearity and reduced interferences.

Conventional amperometric alcohol electrodes were constructed with oxygen- and hydrogen peroxide-base sensors and a much improved electrode was designed by placing a hydrophobic, gas-permeable membrane over the conventional hydrogen peroxide-based alcohol electrode. The immobilization of alcohol oxidase with glutaraldehyde was also studied and optimized. The upper linear ranges of the conventional and newly designed alcohol electrodes were 0.02 and 0.5% ethanol, respectively. The hydrophobic membrane of the new design eliminated the classical electrochemical interferences of hydrogen peroxide-based electrodes and the typical pH dependence of enzymatic systems.     

The β4Integrin Subunit Is Expressed in Mouse Fibroblasts and Modulated by Transforming Growth Factor-β1

Integrin β₄subunit is present in association with α₆chain on both normal and transformed epithelial cells. Recently α₆β₄heterodimer was found on the endothelium of medium-sized blood vessels and on immature thymocytes. In this report we show, by Northern blotting, indirect immunofluorescence, immunoprecipitation, and Western blotting, that β₄subunit is expressed also on cells of mesenchymal origin such as fibroblasts, myoblasts, and myotubes. Increased expression of α₆β₄has been related to the aggressive metastatic phenotype of human and murine carcinomas. The transforming growth factor β₁(TGF-β₁) has been found to modulate the expression of several integrins and intracellular matrix proteins, as well as to stimulate cell invasion and metastatic potential. To evaluate whether α₆β₄expression is modulated by TGF-β₁, we transfected 3T3 fibroblasts with an expression vector carrying the human TGF-β₁cDNA driven by the SV40 early promoter. We observed by indirect immunofluorescence a modification in the subcellular distribution of β₄subunit, which acquires a perinuclear localization. This finding suggests this integrin subunit correlates with the cytoskeletal reorganization induced by TGF-β₁.     

Bloom Syndrome and Maternal Uniparental Disomy for Chromosome 15

Bloom syndrome (BS) is an autosomal recessive disorder characterized by increases in the frequency of sister-chromatid exchange and in the incidence of malignancy. Chromosome-transfer studies have shown the BS locus to map to chromosome 15q. This report describes a subject with features of both BS and Prader-Willi syndrome (PWS). Molecular analysis showed maternal uniparental disomy for chromosome 15. Meiotic recombination between the two disomic chromosomes 15 has resulted in heterodisomy for proximal 15q and isodisomy for distal 15q. In this individual BS is probably due to homozygosity for a gene that is telomeric to D15S95 (15q25), rather than to genetic imprinting, the mechanism responsible for the development of PWS. This report represents the first application of disomy analysis to the regional localization of a disease gene. This strategy promises to be useful in the genetic mapping of other uncommon autosomal recessive conditions.     

Estrogen receptors: new perspectives in breast cancer management

The imbalance between proliferative and differentiative estrogenic effect, caused by quantitative and qualitative alteration of the estrogen receptor (ER) expression, may play a determinant role in mammary neoplastic transformation. Our studies demonstrate that ER levels are significantly higher in human mammary neoplastic tissues when compared to perineoplastic tissues and that increased ER expression is associated with ER gene hypomethylation. During progressive multifactorial carcinogene, ER overexpression may represent an early step in neoplastic transformation. In fact, high levels of ER represent good markers of differentiation and can predict the likelihood of benefiting from anti-estrogen therapy. Nevertheless, about 35% of ER-positive breast cancers are resistant to endocrine therapy and 10% of ER-negative tumors behave as hormone-sensitive tumors. Recent studies on ER mRNA variants, which naturally occur in human breast tumors, demonstrated mutations, deletions and alternative splicings, yielding deletions of exons 3, 4, 5 and 7. ER variants exhibited altered functions or changed the responsiveness to hormonal therapy. Analysis of these variants could be a useful parameter to better predict tumor responsiveness to anti-estrogen therapy. Recently, a regain of hormonal responsiveness by ER-negative breast cancer cells has been reported following ER gene transfection. However, estradiol treatment inhibits rather than stimulates cell growth as well as the metastatic and invasive potential of the ER gene transduced cells. Transfer of the ER gene may be considered as a new therapeutic approach in the management of hormone-independent breast cancer.     

A Chronobiological Approach to Circulating Levels of Renin, Angiotensin-Converting Enzyme, Aldosterone, ACTH, and Cortisol in Addison's Disease

This study deals with a chronobiological approach to the circadian rhythm of the renin-angiotensin-aldosterone system (RAAS) and the ACTH-cor-tisol axis (ACA) in patients with Addison's disease (PAD). The aim is to explore the mechanism(s) for which the circadian rhythmicity of the RAAS and ACA takes place. The study has shown that both the RAAS and ACA are devoid of a circadian rhythm in PAD. The lack of rhythmicity for renin and ACTH provides indirect evidence that their rhythmic secretion is in some way related to the circadian oscillation of aldosterone and cortisol. This implies a new concept: a positive feedback may be included among the mechanisms which chronoregulate the RAAS and ACA.     

Role of fungal patchiness on vegetal detritus in the trophic interactions between two brackish detritivores,Idotea baltica and Gammarus insensibilis

We investigated patterns of resource partitioning between two brackish crustaceans (I. baltica and G. insensibilis) on trophic mosaics of fungal species colonizing vegetal detritus. Laboratory feeding experiments were carried out to assess consumption rates and diet selection of single individuals belonging to five populations. Adults of two co-occurring population of both G. insensibilis and I. baltica and one population of G. insensibilis, occurring alone in another habitat patch, were studied. Each individual were offered both fragments of Cymodocea nodosa conditioned by 8 fungal species and sterilized fragments as sole food source for 7 days. Both species preferred "conditioned" detritus but potential resource use was greater in G. insensibilis than in I. baltica. Individual niche breadth increased and phenotypic variability reduced in the allotopic sample. Trophic similarities were lower between individuals of co-occuring populations than between I. baltica and the allotopic G. insensibilis. The results suggest that co-occurrence is an important factor contributing to the enhancement of phenotypic variability and, consequently, to a trophic generalization at population level in G. insensibilis. It emphasizes the role of fungal patchiness on detritus in regulating resource partitioning between the two species.     

The Degradation of Romanowsky-Type Blood Stains in Methanol

The oxidative demethylation of Romanowsky-type stains in methanol has been examined quantitatively with respect to its effect upon the staining of blood smears. Spectral changes in hound dye, observed through two color filters, have been measured for the nuclei and cytoplasm of segmented neutrophils and monocytes utilizing the LARC™ automated differential analyzer. Stain decomposition in methanol results in a large loss in staining intensity with little change in color. The loss in intensity has been correlated with the observed spectral changes in the degraded stain. High-performance liquid chromatographic analysis of degraded stain samples has shown the products of methanolic degradation to be different from those obtained in aqueous polychroming reactions. To maintain a stain of defined thiazine dye composition and thus defined staining properties, refrigeration is recommended.     

Serum angiotensin-converting enzyme activity in pre-eclamptic pregnancy: evidence for a relative hypermesorACEemia

The circadian rhythm of serum angiotensin-converting enzyme (ACE) activity was investigated in pregnant women with normal and pre-eclamptic gestation. The chronobiological approach was able to document the occurrence of a circadian rhythm for serum ACE activity in normal pregnancy. Such a rhythm is characterized by a decreased mesor and amplitude and a shifted crest. The circadian rhythm for serum ACE activity was not detectable in pre-eclamptic pregnancy. Such an abrogation is accompanied by a negligible decrease of mesor suggesting the occurrence of a relative hyperACEemia. This disorder could play a role in pregnancy-induced hypertension.     

Evaluation of chemokine and cytokine profiles in osteoblast progenitors from umbilical cord blood stem cells by BIO-PLEX technology

We have used cytokine protein array to analyze the secretion of cytokines from an osteoblastic clone derived from human umbilical cord blood mesenchymal stem cells (MSCs) cultured in an osteogenic differentiation medium. The analysis demonstrated the unexpected ability of osteoblast committed cells and their early progenitors to produce significant amounts of a range of soluble immune mediators without in vitro exposure to clinically relevant bacterial pathogens. The cells were expanded and their osteogenic potential analyzed over 45 days of culture was revealed by the expression of osteoblast-specific markers (alkaline phosphatase and Runx2), and by matrix mineralization. Over this culture period, the cells secreted particularly high levels of IL-8, MCP-1 and VEGF, but did not express IL-2, IL-7, IL-17, eotaxin, G-CSF and IFN-gamma. These findings should encourage the use of human umbilical cord blood as a potential stem cells source for bone regeneration.