Hormonal and reproductive influences and risk of melanoma in women

Ratiometric images of cytoplasmic Ca2+ concentration ([Ca2+]c) in individual cells were recorded simultaneously with a confocal ultraviolet-laser microscope in the Indo-1-loaded islets isolated from mice. After changes in [Ca2+]c in response to glucose or amino acids were recorded, the islet was fixed, permeabilized, and stained by the indirect immunofluorescence method against insulin or glucagon in situ; the individual cells were then identified in the focal plain identical to that used for the [Ca2+]c imaging. Almost all cells identified as insulin-positive (beta-cells) by their distinct immunofluorescence responded to the increase in glucose concentration from 3 to 11 mmol/l with an increase in [Ca2+]c. Major populations of cells (approximately 65%) identified as glucagon-positive (alpha-cells) responded to the addition of arginine (5-10 mmol/l) to 3 mmol/l glucose solution with an increase in [Ca2+]c. About half of the alpha-cells (47.6%) responded to the addition of alanine (5-10 mmol/l) to 3 mmol/l glucose solution with an increase in [Ca2+]c. In contrast, <13% of beta-cells responded to the addition of alanine (5-10 mmol/l) or arginine (5-10 mmol/l) to 3 mol/l glucose with an increase in [Ca2+]c. More than one-fourth of alpha-cells responded with an increase in [Ca2+]c when glucose concentration in perifusion solution was reduced from 11 to 0 mmol/l. These results indicate that [Ca2+]c changes in islet cells stimulated by glucose or amino acid were characteristic of the cell species, at least in the alpha- and beta-cell. This technique provides a useful tool to investigate not only the intracellular signal transduction but also the intercellular signal transmission in the intact islet.     

Ureteral stricture formation after removal of impacted calculi

PURPOSE: We retrospectively evaluated the records of 21 patients a mean of 46.1 years old with ureteral stones that had been impacted for greater than 2 months to determine predisposing factors for stricture formation. MATERIALS AND METHODS: Between January 1993 and September 1996, 21 patients were referred for ureteral stones that had remained unchanged in location for at least 2 months. In 11 patients previous attempts at stone removal had failed. Each patient underwent successful stone extraction by retrograde or percutaneous antegrade ureteroscopy, or laparoscopic or open ureterolithotomy. Outcome was determined by reviewing the clinical records and radiographic studies, including excretory urography and nephrostography. RESULTS: Average duration of stone impaction before definitive treatment was 8.8 months (range 2 to 48) and mean stone size was 10.3 mm. (range 1 to 30). All stones were calcium based. There were 3 proximal, 8 mid and 10 distal ureteral calculi. At a mean followup of 7 months ureteral strictures developed in 5 patients (24%) at the previous stone site. Mean duration of stone impaction was 11 months (range 5 to 17) in patients with stricture versus 8.2 months (range 2 to 48) in those with no stricture. Four of the 5 strictures occurred in patients who had had iatrogenic ureteral perforation during previous unsuccessful attempts at stone removal. CONCLUSIONS: Ureteral stone impaction more than 2 months in duration is associated with a 24% incidence of stricture formation. Ureteral perforation at the site of the stone was identified as the primary risk factor for stricture formation in these cases.     

Targeted downregulation of caveolin-1 is sufficient to drive cell transformation and hyperactivate the p42/44 MAP kinase cascade

Caveolin-1 is a principal component of caveolae membranes in vivo. Caveolin-1 mRNA and protein expression are lost or reduced during cell transformation by activated oncogenes. Interestingly, the human caveolin-1 gene is localized to a suspected tumor suppressor locus (7q31.1). However, it remains unknown whether downregulation of caveolin-1 is sufficient to mediate cell transformation or tumorigenicity. Here, we employ an antisense approach to derive stable NIH 3T3 cell lines that express dramatically reduced levels of caveolin-1 but contain normal amounts of caveolin-2. NIH 3T3 cells harboring antisense caveolin-1 exhibit anchorage-independent growth, form tumors in immunodeficient mice and show hyperactivation of the p42/44 MAP kinase cascade. Importantly, transformation induced by caveolin-1 downregulation is reversed when caveolin-1 protein levels are restored to normal by loss of the caveolin-1 antisense vector. In addition, we show that in normal NIH 3T3 cells, caveolin-1 expression levels are tightly regulated by specific growth factor stimuli and cell density. Our results suggest that upregulation of caveolin-1 may be important in mediating contact inhibition and negatively regulating the activation state of the p42/44 MAP kinase cascade.     

Valsalva minimal leak point pressure: a useful approximation to type III female urinary incontinence

Aging is associated with changes in physical characteristics and decline of many physiological functions. The aging process have been described by various theories, in particular the free radical theory of aging has received widespread attention. It has been accepted that the oxidative stress or damage induced by free radicals is related to aging. In this study, we determined the serum concentration of lipid peroxide and antioxidant as biomarker for aging. Healthy subjects were classified into 3 groups, elderly (65-), middle-aged (40-64) and young group (20-39). Findings in the elderly were as follows: 1. Lipid peroxides in the elderly group were significantly higher than those in the young group. 2. Preventive antioxidant concentrations of superoxide dismutase, glutathione peroxidase and albumin were lower than those in the young group, but ceruloplasmin values increased and catalase activity was unchanged. 3. The total antioxidant capacity of serum was slightly decreased. 4. Superoxide generation by neutrophils while resting was significantly higher in the young group.     

Inhibitory action of a truncated derivative of the amphibian skin peptide dermaseptin s3 on Saccharomyces cerevisiae

The inhibitory activity of a truncated derivative of the natural amphibian skin peptide dermaseptin s3-(1-16)-NH2 [DS s3 (1-16)] against Saccharomyces cerevisiae was studied. Significant growth inhibition was observed after exposure to 3.45 microgram of the peptide per ml at pH 6.0 and 7.0, with complete growth inhibition occurring at 8.63 microgram of peptide per ml for all pH values tested. Using confocal scanning laser microscopy, we have shown that DS s3 (1-16) disrupted the yeast cell membrane resulting in the gross permeabilization of the cell to the nuclear stain ethidium bromide. However, the principal inhibitory action of the peptide was not due to disruption of intracellular pH homeostasis. Instead, growth inhibition by the peptide correlated with the efflux of important cellular constituents such as ADP, ATP, RNA, and DNA into the surrounding medium. The combination of DS s3 (1-16) with mild heating temperatures as low as 35 degreesC significantly enhanced the inhibitory effect of the peptide (8.63 microgram/ml), and at 45 degreesC greater than 99% of the population was killed in 10 min. In summary, a derivative of a natural antimicrobial peptide has potential, either alone or in combination with mild heating, to prevent the growth of or kill spoilage yeast.     

Model for ocular tear film function

Blepharitis patients have a number of disturbances in their tear film associated with meibomian gland dysfunction that affect evaporation and tear osmolarity. We tested a series of 156 consecutive patients, with a presumed diagnosis of blepharitis, dry eye, or allergic disease, and a series of 72 normals. We compared their tear film characteristics using tear osmolarity, tear volume, tear production (fluorophotometric and Schirmer test), tear turnover (decay constant), tear evaporation, and meibomian gland function evaluated by gland drop-out, expressed lipid viscosity, and volume. Of the 156 patients tested, we found 37 had dry eye, 10 had only allergic disease, 73 had meibomian gland dysfunction and dry eye, and 36 had only meibomian gland dysfunction. We created a model of the relative influence some of these factors had on each other using their correlation coefficients. The highest correlations for osmolarity were Schirmer test (-0.44), lipid volume low (-0.44), lipid viscosity high (0.39), gland drop-out (0.39), and tear evaporation (0.36). With regression analysis we accounted for 47% of the total variation in osmolarity, but only 17% of the variation in tear evaporation. We also present our classification system for blepharitis and dry eye patients based on our measurable physiologic parameters.     

Evidence for sexual differentiation of glia in rat brain

It is well established that gonadal steroids mediate sexual differentiation of the brain via direct effects on neurons during a restricted critical period. In addition, estrogen can influence glial morphology in the adult brain, and in vitro studies suggest estrogen induces glial differentiation. However, there is a lack of in vivo evidence for steroid effects on glia during the critical period. We report here a hormone-mediated sexual differentiation of arcuate glia as early as Postnatal Day 1. Using glial fibrillary acidic protein immunoreactivity (GFAP-ir), we compared the responsiveness of astroglia in the rat arcuate nucleus among five hormonally different groups. The results indicate increased GFAP-ir cell surface area 24 hr after hormonal manipulation in castrate males compared to intact males, intact females (ANOVA; P < 0.01), and females injected with testosterone propionate (50 microg; ANOVA; P < 0.05). However, astroglia in intact males extended their processes significantly greater distances from the cell body compared to all other treatment groups (ANOVA; P < 0.01). The GFAP-ir cells were categorized into four distinct classes ranging from a simple bipolar to a fully stellate morphology. The frequency distribution of classes varied between groups with more stellate cells found in intact males. Finally, these sex differences in arcuate glia persisted into adulthood. We hypothesize that during the critical period, testosterone, or its metabolite estrogen, induce sexual differentiation of glia. We further hypothesize that in females glial cells remain partially undifferentiated and this may be important to glial plasticity seen in adult female arcuate.     

CYP2D6 mRNA expression in circulating peripheral blood mononuclear cells correlates with in vivo debrisoquine hydroxylase activity in extensive metabolizers

The interaction of microtubule associated proteins (MAPs) with the microtubule system has been characterized in depth in neuronal cells from various mammalian species. These proteins interact with well-defined domains within the acidic tubulin carboxyl-terminal regulatory region. However, there is little information on the mechanisms of MAPs-tubulin interactions in nonmammalian systems. Recently, a novel tau-like protein designated as DMAP-85 has been identified in Drosophila melanogaster, and the regulation of its interactions with cytoskeletal elements was analyzed throughout different developmental stages of this organism. In this report, the topographic domains involved in the binding of DMAP-85 with tubulin heterodimer were investigated. Affinity chromatography of DMAP-85 in matrixes of taxol-stabilized microtubules showed the reversible interaction of DMAP-85 with domains on the microtubular surface. Co-sedimentation studies using the subtilisin-treated tubulin (S-tubulin) indicated the lack of association of DMAP-85 to this tubulin moiety. Moreover, studies on affinity chromatography of the purified 4 kDa C-terminal tubulin peptide bound to an affinity column, confirmed that DMAP-85 interacts directly with this regulatory domain on tubulin subunits. Further studies on sequential affinity chromatography using a calmodulin affinity column followed by the microtubule column confirmed the similarities in the interaction behaviour of DMAP-85 with that of tau. DMAP-85 associated to both calmodulin and the microtubular polymer. These studies support the idea that the carboxyl-terminal region on tubulin constitutes a common binding domain for most microtubule-interacting proteins.     

Low dose desensitisation does not reduce the toxicity of sulphasalazine in rheumatoid arthritis

To investigate the apoptosis-inducing effect of glucocorticoid on gastric epithelial cell expressing different p53 genes, a human gastric epithelial cell line-GES-1 was transfected with either wild type or mutant p53 cDNA in vitro. The cells were treated with hydrocortisone in a concentration range of 0.2-0.8 g/L. Apoptotic cells were found in those transfectants. The apoptotic response of the wild-type p53-transfected GES-1 cells was much more marked than that of the mutant p53 transfected ones. It can be inferred that the glucocorticoid secreted not only suppress the immunological response during inflammation, but induce gastric epithelial cell apoptosis as well. If the gastric epithelial cell contains mutant p53 genes, the glucocorticoid confer a selective growth advantage which advance the malignant process.