Global sequence diversity of BRCA2: analysis of 71 breast cancer families and 95 control individuals of worldwide populations

The aim of this study was to evaluate the prevalence of simple sequence variation in the BRCA2 gene. To this end, 71 breast and breast-ovarian cancer (HBC/HBOC) families along with 95 control individuals from a wide range of ethnicities were analyzed by means of denaturing high-performance liquid chromatography (DHPLC) and direct sequence analysis. In the coding (10 257 bp) and non-coding (2799 bp) sequences of BRCA2, 82 sequence variants were identified. Three different, apparently disease-associated BRCA2 mutations were found in six HBC/HBOC families (8%): two splice site mutations in introns 5 and 21, and one frameshift mutation in exon 11. In the coding region, 53 simple sequence variants were found: 35 missense mutations, one 2 bp deletion (CT) resulting in a stop at codon 3364, one nonsense mutation with a stop at codon 3326, one deletion of a complete codon (AAA) resulting in the loss of leucine, and 15 silent mutations. In the non-coding region, 26 polymorphisms were detected. Of the 79 sequence variants that were not obviously disease-associated, eight were detected only in HBC/HBOC families. The remaining 71 variants were identified in both HBC/HBOC families and control individuals. Sixty three sequence variants (80%) were specific for a continent. Forty two percent (33 out of 79) of the sequence variants were detected exclusively in Africa, though only 13% of the 332 chromosomes screened were of African origin. Our data indicate that, in BRCA2, simple sequence variation is frequent [in the coding region 1 in 194 bp (straight theta = 2.2 x 10(-4)), and in the non-coding region 1 in 108 bp (straight theta = 4.4 x 10(-4)), respectively].     

Pathological features and prognostic significance of prostate cancer in the apical section determined by whole mount histology

PURPOSE: We test the hypothesis that cancer in the apical section of the prostate is an important independent factor in predicting the progression of clinically localized prostate cancer. MATERIALS AND METHODS: We analyzed clinical data and whole mount histological step sections for 500 patients who had undergone radical retropubic prostatectomy for clinically localized prostate cancer. RESULTS: Cancer was in the apex of the prostate in 175 patients (35%). These patients had a larger cancer and higher incidence of positive surgical margins, and were more likely to have a poorly differentiated cancer than the 325 patients without cancer in the apex. However, the presence of apical cancer was not a significant predictor of clinical or prostate specific antigen progression in either univariate or multivariate Cox proportional hazards models when analyzed for the entire group or only in patients with tumor confined to the prostate. CONCLUSIONS: Apical cancer in a radical prostatectomy specimen is simply a sign of a larger volume cancer and is not independently associated with an increased risk of clinical or prostate specific antigen progression.     

Resonant disk turnstile

In this paper, the resonant disk turnstile is introduced and analyzed. The disk turnstile differs from Dicke's full-waveguide turnstile in that four of the six ports are coaxial cable ports, yielding a much more compact turnstile, which is easier to construct. The disk turnstile operation is explained as a superposition of the disk TM₀₁ mode (nonradiating) and the disk TM₁₁ mode which couples directly to the circular waveguide (dominant) TE₁₁ mode. A useful operating fractional bandwidth of 3% is possible as compared to a Dicke turnstile bandwidth of about 6%     

Regulation of lung liquid secretion in immature fetal sheep: hormonal interaction

The present studies were designed to test the hypothesis that arginine vasopressin (AVP) can interact with hydrocortisone and 3,5,3'-triiodothyronine (T3) to induce maturation of lung liquid reabsorptive processes in fetal sheep < 130 days gestation. Lung liquid production rates were measured in chronically catheterized thyroidectomized fetal sheep during eight different experimental treatments. Each experiment consisted of a 2-h control period followed by a 5-h treatment period. Net secretion or reabsorption of lung liquid was measured by using impermeant marker dilution techniques. AVP alone (50 mU/kg bolus plus 5.0 mU.kg-1.min-1 i.v. infusion) does not alter lung liquid secretion in fetal sheep 125 +/- 0.72 (SE) days gestation. In contrast, AVP (same dose as above) with T3 (30 micrograms) and hydrocortisone (6.94 mg/min) depressed lung liquid secretion and caused reabsorption of fluid. T3 alone, T3 and hydrocortisone, T3 and AVP, hydrocortisone alone, hydrocortisone and AVP, and saline did not result in net lung liquid reabsorption over a 5-h treatment period. These investigations demonstrate that AVP, T3, and hydrocortisone interact to cause lung liquid reabsorption in immature fetal lungs.     

Detection and determination of theobromine and caffeine in urine after administration of chocolate-coated peanuts to horses

BACKGROUND AND OBJECTIVES: Most patients with colorectal liver metastases are not eligible for resection because they have multiple lesions or because of anatomical constraints. We report the use of cryotherapy to destroy residual metastases following liver resection in patients with disease too widespread for treatment by resection alone. METHODS: Twenty patients with bilobar disease confined to the liver (median 3; range 2-8 lesions) were treated in this way. Seventeen patients also received regional chemotherapy postoperatively. RESULTS: Morbidity was high, but there were no procedure-related deaths and only one patient's hospital stay exceeded 24 days. Significant destruction of tumor, as evidenced by a decline in CEA levels, occurred within 3 months of surgery in all patients (P < 0.001). Median duration of follow-up was 15 (6-53) months. Survival rates at 1 and 2 years were 88% and 60%, respectively, and median survival was 32 months. Seven patients remain well and seven are alive with recurrent liver and/or other metastases. CONCLUSIONS: Although this is not a control study, it would appear that some patients with irresectable liver metastases benefit from this multimodality approach.     

Leukotrienes in renal transplant rejection in rats. Distinct roles for leukotriene B4 and peptidoleukotrienes in the pathogenesis of allograft injury

To investigate the role of leukotrienes in renal allograft rejection, we studied the effects of specific leukotriene inhibitors in a rat kidney transplant model. The enhanced renal production of leukotrienes observed in allograft recipients was reduced in a dose-dependent manner by the specific 5-lipoxygenase inhibitor MK886. This suppression of leukotriene production caused a substantial improvement in renal function. Inhibition of 5-lipoxygenase also reduced the severity of vascular inflammation and endothelial injury in allografts, and profoundly inhibited expression of donor MHC class II Ag on kidney cells. Survival of renal allograft recipients was prolonged from 10 +/- 1 days in controls to 16 +/- 1 days in animals that received a 6-day course of MK886 (p < 0.05). To investigate the relative roles of LTB4 compared to peptidoleukotrienes in these processes, we treated a separate group of animals with the specific peptidoleukotriene receptor antagonist SKF106203. This agent inhibits the interaction of peptidoleukotrienes with their receptor(s) but does not affect the biologic actions of LTB4. In these studies, SKF106203 caused a modest improvement in renal allograft function that was of lesser magnitude than that seen with the 5-lipoxygenase inhibitor. SKF106203 also reduced vascular inflammation in allografts, but had no effect on expression of MHC class II Ag. We conclude that leukotrienes play a key role in the pathogenesis of renal allograft rejection. Furthermore, the detrimental effects of leukotrienes in rejection are mediated by distinct actions of LTB4 and peptidoleukotrienes.     

Colorectal cancer incidence and survival among Alaska Natives, 1969-1993

BACKGROUND: Although colorectal cancer rates are low among most groups of Native Americans in North America, rates for Alaska Natives have been substantially elevated compared with US rates for all races combined. METHODS: To better describe the epidemiology of colorectal cancer incidence and survival among Alaska Natives, stratified by gender and tribal/ethnic affiliation, we examined data collected by the Alaska Native Cancer Registry 1969-1993. We calculated age-adjusted and age-specific incidence as well as actuarial survival rates, and examined histological type, site, stage at diagnosis, and treatment. We compared these data to colorectal cancer data from whites living in western Washington. RESULTS: In all, 587 colorectal cancer cases were identified among Alaska Natives over the 25-year period, for an age-adjusted annual incidence rate of 71.4/100000 in women, and 69.3/100000 in men. Compared to Alaska Indians, colon cancer rates were significantly higher in Aleuts (relative risk [RR] = 1.6, 95% CI: 1.2-2.2) and in Eskimos (RR = 1.5, 95% CI: 1.2-1.8), while rectal cancer rates did not differ by race/ethnicity. Alaska Natives experienced a 50% higher incidence rate of colorectal cancer overall compared to western Washington whites (RR = 1.5, 95% CI: 1.3-1.6), although rectal cancer rates were similar in the two populations. The highest RR were seen among Alaska Native women; Aleuts and Eskimos had colon cancer rates more than twice that of western Washington white women. No unusual qualitative features were found in the cancers occurring in Alaska Natives. Actuarial colorectal cancer survival rates for Alaska Natives overall were 74% at one year and 42% at 5 years; these rates were very similar to those observed for the western Washington population. Both one and 5-year survival rates showed a significant trend towards improvement over time. CONCLUSIONS: Alaska Natives had substantially higher colorectal cancer incidence rates compared to western Washington whites. Rates were particularly high for Aleut and Eskimo women. These data suggest a need for intensified secondary prevention strategies for this high-risk population, while further research is needed to identify modifiable risk factors.     

Evidence that glucose metabolism regulates leptin secretion from cultured rat adipocytes

Circulating leptin secreted from adipocytes is correlated with fat mass and plasma insulin concentrations in humans and rodents. Plasma leptin, insulin, and glucose decrease during fasting and increase after refeeding; however, the underlying mechanisms regulating the changes of leptin secretion are not known. To investigate the role of insulin-stimulated glucose metabolism in the regulation of leptin secretion, we examined the effects of insulin and inhibitors of glucose transport and metabolism on leptin secretion from rat adipocytes in primary culture. Insulin (0.16-16 nM) increased leptin secretion over 96 h; however, the increase in leptin was more closely related to the amount of glucose taken up by the adipocytes (r = 0.64; P < 0.0001) than to the insulin concentration per se (r = 0.20; P < 0.28), suggesting a role for glucose transport and/or metabolism in regulating leptin secretion. 2-Deoxy-D-glucose (2-DG), a competitive inhibitor of glucose transport and phosphorylation, caused a concentration-dependent (2-50 mg/dl) inhibition of leptin release in the presence of 1.6 nM insulin. The inhibitory effect of 2-DG was reversed by high concentrations of glucose. Two other inhibitors of glucose transport, phloretin (0.05-0.25 mM) and cytochalasin-B (0.5-50 microM), also inhibited leptin secretion. Inhibition of leptin secretion by these agents was proportional to the inhibition of glucose uptake (r = 0.60 to 0.86; all P < 0.01). Two inhibitors of glycolysis, iodoacetate (0.005-1.0 mM) and sodium fluoride (0.1-5 mM), produced concentration-dependent inhibition of leptin secretion in the presence of 1.6 nM insulin. In addition, both 2-DG and sodium fluoride markedly decreased the leptin (ob) messenger RNA content of cultured adipocytes, but did not affect 18S ribosomal RNA content. We conclude that glucose transport and metabolism are important factors in the regulation of leptin expression and secretion and that the effect of insulin to increase adipocyte glucose utilization is likely to contribute to insulin-stimulated leptin secretion. Thus, in vivo, decreased adipose glucose metabolism may be one mechanism by which fasting decreases circulating leptin, whereas increased adipose glucose metabolism would increase leptin after refeeding.     

Single strand breaks and mutagenesis in yeast induced by photodynamic treatment with chloroaluminum phthalocyanine

The CD53 antigen is a member of the tetraspan family of proteins with unknown function. Stimulation of rat IR938F B-cell lymphoma cells with monoclonal antibody MRC OX44 (anti-rat CD53) triggered a homotypic adhesion reaction which reached a maximum effect at 24 hr. This effect occurred at 37 degrees C but not at 4 degrees C. Adhesion was prevented by removal of divalent cations, Ca2+ and Mg2+, with EGTA and EDTA as chelating agents. The adhesion induced by MRC OX44 was inhibited by cycloheximide and actinomycin D, suggesting that de novo protein synthesis was required for this effect. The addition of mAb WT1 against rat LFA-1 (CD11a) antigen had no effect on adhesion, suggesting that the cell-cell interaction is not mediated by the expression of LFA-1 antigen. The intracellular signals required to induce adhesion were inhibited by two tyrosine kinase inhibitors, genistein and piceatannol. Wortmannin, a selective inhibitor of phosphoinositide 3-kinase activity, completely blocked adhesion. Two protein kinase C inhibitors, H7 and bisindolylmaleimide, inhibited the adhesion, suggesting that part of the signal is mediated by PKC. Electron microscopy of aggregated cells showed that the interaction is localized to short membrane regions, where contact areas of higher density in opposing zones from both cells were detected. We postulate that there is a common adhesion mechanism that is modulated by several tetraspan family members and associated proteins. This adhesion structure might represent a novel form of cell communication among lymphoid cells.