Gonadal steroids have paradoxical effects on brain oxytocin receptors

Specific brain receptors for oxytocin have been described in several mammalian species. The distribution of these receptors differs greatly across species and in the rat, receptor binding in specific brain regions appears to depend upon gonadal steroids. This study used in vitro receptor autoradiography to examine the effects of testosterone on oxytocin receptor binding in the mouse forebrain. Three groups of male mice were compared: castrates treated with blank capsules, castrates treated with testosterone filled capsules, and intact males. Irrespective of steroid treatment, the distribution of oxytocin receptors in mouse forebrain differed markedly from patterns previously described in the rat. In addition to these species differences in receptor distribution, testosterone had effects in the mouse which differed from the induction of receptors previously reported in the rat. In the mouse ventromedial nucleus of the hypothalamus, binding in the untreated castrate males was approximately double that observed in either the intact or the testosterone-treated castrates. In other regions of the mouse brain, such as the intermediate zone of the lateral septum, binding to oxytocin receptors was increased with testosterone treatment. These results suggest that the brain oxytocin receptor varies across species not only in its distribution but also in its regional regulation by gonadal steroids. These apparently paradoxical changes in oxytocin receptor binding may result from either direct or indirect effects of gonadal steroids in mouse brain.     

Eliminating memory for fragmentation within partitionable SIMD/SPMDmachines

Efficient data layout is an important aspect of the compilation process. A model for the creation of perfect memory maps for large-scale parallel machines capable of user-controlled partitionable single-instruction-multiple data/single-program-multiple data (SIMD/SPMD) operation is developed. The term perfect implies that no memory fragmentation occurs and ensures that the memory map size is kept to a minimum. A major constraint on solving this problem is based on the single program nature of both the SIMD and SPMD modes of parallelism. It is assumed that all processors within the same submachine used identical addresses to access corresponding data items in each of their local memories. Necessary and sufficient conditions are derived for being able to create perfect memory maps, and results are applied to several partitionable interconnection networks     

Fecal occult blood screening in the Minnesota study: role of chance detection of lesions

BACKGROUND: In the Minnesota Colon Cancer Control Study, annual fecal occult blood testing reduced mortality from colorectal cancer by at least 33.4%. Some attribute a large part of this reduction to chance detection of cancers by colonoscopies; rehydration of guaiac test slides greatly increased positivity and consequently the number of colonoscopies performed. This study was conducted to determine how much of the reduction resulted from chance detection. METHODS: We used a mathematical model developed by Lang and Ransohoff to estimate the proportion of the 33.4% mortality attainable by chance alone. Applying the model requires the specification of five parameters: duration of follow-up, rate of compliance with fecal occult blood testing, rate of compliance with colonoscopy, positivity rate, and efficacy of colonoscopy in reducing colorectal cancer mortality. We took values for four of the five parameters directly from the Minnesota study. For the fifth parameter, efficacy of colonoscopy, we selected a value of 60%, based on the conclusions of another study. Whereas the Lang-Ransohoff model selects persons for colonoscopy by chance alone, those with bleeding cancers would also be selected by sensitive fecal occult blood testing. We therefore adjusted the result of the Lang-Ransohoff model for this dual detectability. RESULTS: We found that 16%-25% of the reduction in colorectal cancer deaths effected by fecal occult blood testing in the Minnesota study was due to chance detection; the remainder was due to sensitive detection. CONCLUSION: Chance played a minor role in the detection of colorectal cancers by fecal occult blood testing in the Minnesota study.     

Characterization and sequence of the Escherichia coli panBCD gene cluster

A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of asparate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by orf3, which is oriented in the opposite direction. Interruptions in the remaining open reading frames did not affect growth on glucose-minimal medium. No significant similarity to sequences in databases was found for orf1 and orf2. Orf3 contained extensive similarity to reading frames defined by E. coli yjiP, yjiQ, yhgA, and yafD. The function of these amino acid sequences is as yet undefined.     

Ligature carrier specifically designed for transvaginal sacrospinous colpopexy

The purpose of this paper is to clarify whether copper accumulation in hepatocellular carcinoma (HCC) is a cause of high intensity signal pattern on T1-weighted images (T1-WI) by comparing the histologically proven copper accumulation with MR images. Forty-five surgically resected HCCs were analyzed. Distribution patterns of divalent copper by a modified Timm's method on their maximum cut surfaces were compared with signal patterns on corresponding T1-WI. The degree of copper accumulation in tumor compared with surrounding liver tissue was higher in 6 lesions, equal in 17 lesions, and lower in 22 lesions. High intensity pattern on T1-WI were observed in 3 of 6 lesions (50%), 10 of 17 lesions (59%), and 10 of 22 lesions (45%). Distribution patterns of copper were not correlated with intensity patterns on T1-WI. We conclude that the paramagnetic effect of divalent copper accumulation in HCC is insufficient to influence the MRI.     

Identification of a gene that causes primary open angle glaucoma

Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.     

Cryptococcosis in tree shrews (Tupaia tana and Tupaia minor) and elephant shrews (Macroscelides proboscides)

OBJECTIVE: To determine the relation between metabolic and anthropometric parameters and circulating leptin concentrations in women with polycystic ovary syndrome (PCOS). DESIGN AND PATIENTS: Correlation of fasting serum leptin concentrations with anthropometric measures and multiple metabolic parameters including insulin and glucose responses to a 2-hour 75-g oral glucose tolerance test (OGTT) in 85 women with PCOS (17-36 years, body mass index (BMI) 29.9 +/- 0.9 kg/m2, mean +/- SD) and 18 control women (25-47 years, BMI 25 +/- 1.7 kg/m2). Diagnostic criteria for PCOS: characteristic ovarian morphology on ultrasound plus at least two of (1) elevated serum testosterone; (2) elevated serum androstenedione; and (3) reduced serum SHBG concentrations. MEASUREMENTS: Concentrations of androgens, lipids, PRL, gonadotrophins, and leptin were measured in the baseline fasting blood sample from an OGTT. Insulin and glucose were measured throughout OGTT. Serum leptin concentrations were measured by radioimmunoassay. RESULTS: Log leptin levels in the PCOS group correlated significantly with BMI (r = 0.85, P < 0.0001) and with 8 other parameters including waist/hip ratio (r = 0.51, P = 0.0005). By stepwise regression analysis, only BMI (P < 0.0001) and plasma high density lipoprotein concentration (P = 0.02) were independently correlated with log leptin levels, both positively. There was no effect of fat distribution, as measured by waist/ hip ratio, on leptin concentrations. Comparison of control subjects to a BMI-matched subgroup of 55 PCOS subjects revealed significantly higher circulating concentrations of LH, testosterone, DHEAS, progesterone and androstenedione, and higher glucose and insulin responses to OGTT in the PCOS group. Leptin levels were not different between the PCOS subgroup and control group (14.8 +/- 1.3 vs 12.1 +/- 2.3 micrograms/l, mean +/- SE, P = 0.26) and the relation of BMI to leptin levels determined by linear regression analysis also did not differ between the two groups. CONCLUSIONS: Our results indicate that circulating leptin concentrations in women with PCOS, a condition characterized by hyperandrogenaemia, increased LH concentrations and insulin resistance, are strongly related to BMI and not independently affected by circulating levels of insulin, gonadotrophins or sex hormones.