Analysis of p53 mutation and cyclin d1 expression in breast tumors

P53 and cyclin D1 are interacting regulatory genes and both are frequently altered in breast cancer. We analysed p53 mutation by SSCP and sequencing methods as well as p53 protein accumulation immunohistochemically in 34 consecutively operated breast tumors. None of 4 fibroadenomas revealed p53 mutation or p53 protein accumulation. Mutation of p53 was present in 7 carcinomas. Immunohistochemistry revealed accumulation of p53 protein in 6 carcinomas and there was a significant correlation between p53 mutation and protein accumulation. Overexpression of cyclin D1 protein was observed in 11 carcinomas by immunohistochemistry and no correlation was observed between cyclin D1 overexpression and p53 mutation or accumulation. Our data support the concept that the p53-cyclin D1 signal pathway and the cyclin D1 cascade are disregulated in breast cancer.     

Dexamethasone suppression test and coping behavior in psychosocial stress

The dexamethasone suppression test (DST) and the Minnesota Multiphasic Personality Inventory (MMPI) were administered to 144 healthy inductees on day 2 of military service. One hundred and four of them completed a 120-item questionnaire describing their coping responses to this particular challenge. Thirty-six subjects (25%) failed to suppress plasma cortisol adequately. Their mean scores on the MMPI clinical standard scales were within the normal range. High postdexamethasone cortisol levels were associated with denial and passivity, and with low demand for social support. These results suggest that the DST might be more related to coping with a stressor than to a specific diagnosis. The authors speculate that high hypothalamic-pituitary-adrenal activity may have a primary role in psychological defense promoting inattention to the aversive aspects of stressful situations.     

Follicular fluid concentrations of thiopental and thiamylal during laparoscopy for oocyte retrieval

Because access into ovarian tissue of drugs used during anesthesia may be potentially harmful to the oocyte and/or follicular structure, we measured concentrations of thiopental (n = 15) and thiamylal (n = 9) in follicular fluid (FF) aspirates of 24 patients who underwent laparoscopic oocyte retrieval. In both groups, measurable amounts of the respective drug were found in all FF aspirates. Within individual patients, plasma concentrations of both drugs declined during the period of sampling between initial and final follicular aspiration. The mean plasma drug concentration was 7.99 +/- 3.97 micrograms/ml in the thiamylal group and 4.13 +/- 0.90 micrograms/ml in the thiopental group. Mean drug concentrations in FF were similar in both groups (thiopental 1.62 +/- 0.61 micrograms/ml; thiamylal 1.67 +/- 0.83 micrograms/ml). The mean FF/plasma concentration ratio during the sampling period was greater in the thiopental group (0.41 +/- 0.19) as compared with the thiamylal group (0.22 +/- 0.14). Several steps in the clinical management of these patients can be taken to reduce exposure of oocytes to drugs used during anesthesia.     

Carotid artery auscultation--anachronism or useful screening procedure?

Carotid bruits are supposed to indicate the presence of high-grade common carotid or extracranial internal carotid artery stenosis in a large proportion of patients. Using a stethoscope, we prospectively auscultated 273 carotid arteries of 145 patients blinded to the results of a complete extracranial and intracranial Doppler investigation including extracranial color-coded duplex ultrasound. Fifty-four arteries showed stenosis of > or = 50%-99%, or occlusion of the extracranial internal or the common carotid artery. In 25 of these arteries, a bruit was present. In 9 out of 16 patients with extracranial stenosis from 70%-99%, a bruit was detected. In one additional patient with a middle-grade external carotid artery stenosis, a bruit was also present. In seven additional patients, a bruit was present in the absence of any carotid artery stenosis, cardiac vitium or goiter. The sensitivity of carotid auscultation for the detection of a 70%-99% stenosis of the common or extracranial internal carotid artery was 56% and specificity was 91%. The positive predictive value of a bruit found during carotid auscultation was 27%, and the negative predictive value of a normal auscultation was 97%. Carotid auscultation is a useful screening procedure in the detection of carotid stenosis or occlusion, but requires confirmation by carotid ultrasound.     

Models of chronic kidney disease

Chronic kidney diseases result from recurrent or progressive injuries in glomeruli, tubules, interstitium and/or vasculature. In order to study pathogenesis, mechanisms and effects of interventions, many animal models have been developed, including spontaneous, genetic and induced models. However, these models do not exactly simulate human diseases, and most of them are strain, gender or age dependent. We review key information on various rodent models of chronic kidney diseases.     

Regulation of proliferation of skeletal muscle precursor cells by NADPH oxidase

Skeletal muscle precursor cells are adult stem cells located among muscle fibers. Proliferation, migration, and subsequent differentiation of these cells are critical steps in the repair of muscle injury. We document in this study the roles and mechanisms through which the NAPDH oxidase complex regulates muscle precursor cell proliferation. The NADPH oxidase subunits Nox2, Nox4, p22(phox), p47(phox), and p67(phox) were detected in primary human and murine skeletal muscle precursor cells. In human muscle precursor cells, NADPH oxidase-fusion proteins were localized in the cytosolic and membrane compartments of the cell, except for p47(phox), which was detected in the nucleus. In proliferating subconfluent precursor cells, both Nox2 and Nox4 contributed to O(2)(-) production. However, Nox4 expression was significantly attenuated in differentiated myotubes. Proliferation of precursor cells was significantly reduced by antioxidants (N-acetylcysteine and apocynin), inhibition of p22(phox) expression by using siRNA oligonucleotides, and reduction of Nox4 and p47(phox) activities with dominant-negative vectors and siRNA oligonucleotides resulted in attenuation of activities of the Erk1/2, PI-3 kinase/AKT and NFkappaB pathways and significant reduction in cyclin D1 levels. We conclude that NADPH oxidase is expressed in skeletal muscle precursor cells and that its activity plays an important role in promoting proliferation of these cells.     

Lack of integrin alpha1beta1 leads to severe glomerulosclerosis after glomerular injury

Severity of fibrosis after injury is determined by the nature of the injury and host genetic susceptibility. Metabolism of collagen, the major component of fibrotic lesions, is, in part, regulated by integrins. Using a model of glomerular injury by adriamycin, which induces reactive oxygen species (ROS) production, we demonstrated that integrin alpha1-null mice develop more severe glomerulosclerosis than wild-type mice. Moreover, primary alpha1-null mesangial cells produce more ROS both at baseline and after adriamycin treatment. Increased ROS synthesis leads to decreased cell proliferation and increased glomerular collagen IV accumulation that is reversed by antioxidants both in vivo and in vitro. Thus, we have identified integrin alpha1beta1 as a modulator of glomerulosclerosis. In addition, we showed a novel pathway where integrin alpha1beta1 modulates ROS production, which in turn controls collagen turnover and ultimately fibrosis. Because integrin alpha1beta1 is expressed in many cell types this may represent a generalized mechanism of controlling matrix accumulation, which has implications for numerous diseases characterized by fibrosis.     

Electrophoretic karyotype of two Micromucor species

Electrophoretic karyotype analysis was applied to obtain information on the organisation and intrageneric variability of the nuclear genome in three Micromucor isolates of two different species (M. isabellina and M. ramanniana). A protoplast formation protocol, conditions for the preparation of highly-intact chromosome-size DNA molecules and for the separation of DNA molecules were established. The chromosomal banding patterns revealed substantial variability among the isolates: 11 to 14 chromosomal mobility groups were resolved. The DNA in the Micromucor chromosomes were rather small; their estimated sizes were calculated to be between 2.60 and 0.4 Mb. Using Saccharomyces cerevisiae and Schizosaccharomyces pombe as size standard, the minimum total genome sizes were estimated to be between 24.19 and 24.9 Mb.     

Recruitment of NIMA kinase shows that maturation of the S. pombe spindle-pole body occurs over consecutive cell cycles and reveals a role for NIMA in modulating SIN activity

Mitotic exit in Saccharomyces cerevisiae and septation in Schizosaccharomyces pombe are regulated by a conserved signaling network called the mitotic exit and septum initiation networks (SIN), respectively. The network is active on one of the two anaphase B spindle-pole bodies (SPBs). Whereas the inherent asymmetry of growth by budding accounts for elements of the asymmetry in S. cerevisiae, it has been unclear how, or why, the pathway is asymmetric in S. pombe. We show that elements of SPB duplication in S. pombe are conservative, and that the SIN is active on the new SPB. SIN association with the new SPB persists after transient depolymerization of microtubules. The localization of the NIMA-related kinase, Fin1, reveals further complexity in SPB inheritance. Fin1 associates with the SPB bearing the older components in all cells and with the "new" SPB in half of the population. Fin1 only binds the new SPB when this new SPB has arisen from the duplication of an SPB that is two or more cycles old. Thus, each of the four SPBs generated over two consecutive cell cycles are different, because they have distinct fates in the next cell cycle. Fin1 binds the SPB once the SIN is active and the association requires the SIN inhibitors Byr4 and Cdc16. Fin1 physically associates with Byr4. Compromising Fin1 function leads to SIN activation on both anaphase B SPBs and promotes septation, indicating that Fin1 restrains SIN activity on the old SPB.