Characterization of the androgen receptor in a benign prostate tissue-derived human prostate epithelial cell line: RC-165N/human telomerase reverse transcriptase

The majority of prostate epithelial cell lines stably expressing wild-type (wt) or mutant (mt) androgen receptor (AR) are derived from metastatic prostate cancers. Therefore, the wt AR-expressing RC-165N/human telomerase reverse transcriptase (hTERT) cell line derived from the benign prostate tissue of an African-American patient provides a unique opportunity to assess the functional status of AR in a cellular context not studied before. Although androgen-induced expression of known androgen responsive genes such as PMEPA1, and NDRG1 was observed in RC-165N/hTERT, this cell line expresses prostate-specific antigen (PSA) at significantly lower levels. Chromatin immunoprecipitation assay revealed androgen-dependent binding of AR to androgen response elements of PSA, PMEPA1 and NDRG1 genes. Similarities, as well as differences were noted in the expression of androgen responsive genes between RC-165N/hTERT and LNCaP cells. Comprehensive evaluations of AR functions in RC-165N/hTERT cells suggest that whereas some features of known AR functions are maintained in this benign prostatic tissue-derived cell line, other AR functions are not retained. Objective evaluations of similar cell lines will lead to the understanding of AR functions in prostate growth and differentiation.

Effects of positive end-expiratory pressure on systemic haemodynamics, with special interest to central venous and common iliac venous pressure in liver transplanted patients

BACKGROUND AND OBJECTIVES

Positive end-expiratory pressure may alter cardiac function and systemic haemodynamics. As transplanted livers may be sensitive to liver congestion, the aim of our study was to evaluate the effect of positive end-expiratory pressure on the cardiovascular system and in particular on central venous and iliac venous pressure in liver transplanted patients.

PATIENTS AND METHODS

Seventy-two liver transplant patients were enrolled in this prospective, interventional study. On admission to our Intensive Care Unit all patients were ventilated in a biphasic positive airway pressure mode. Haemodynamic effects of three randomly set levels of end-expiratory pressures (0, 5 and 10 mbar) were studied in the immediate postoperative period in all patients. Mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, central iliac venous pressure and cardiac index were recorded and analysed at each of the three end-expiratory pressure levels.

RESULTS

The values of central- and wedge-pressure significantly increased with increased end-expiratory pressure. Central venous pressure increased by 24% and wedge pressure showed a 6% increase at 10 mbar in comparison to 0 mbar. The values for cardiac index and mean arterial pressure showed no statistically significant difference at 10 mbar as compared to 0 and 5 mbar. The mean pulmonary arterial and common iliac venous pressure were unaffected by different positive end-expiratory pressure levels.

CONCLUSIONS

Short-term pressure controlled ventilation with end-expiratory pressure up to 10 mbar does not significantly impair systemic haemodynamics in liver-transplanted patients. Further studies are needed to determine whether these findings could be confirmed with higher pressure levels and/or over a longer period of ventilation time.

A phase II randomized controlled trial of a novel male contraception, an intra-vas device

The aim of this study was to introduce a novel male contraceptive method, an intra-vas device (IVD), and to assess the efficacy, safety and satisfaction of recipients compared with no-scalpel vasectomy (NSV). A phase II randomized controlled trial was conducted in China in 2003. Two hundred and eighty-eight male subjects seeking vasectomy were randomly assigned to the IVD or NSV group. Follow up included a telephone questionnaire on the 14th postoperative day and visits at the third and 12th postoperative months. The follow-up rates at the three time points were 100%, 100% and 96.5% respectively. There was no technical failure in any subject. The surgical conditions were similar in both groups, but the IVD group experienced an additional 5 min of operative time (p<0.001). The IVD group recovered normal activity and sexual intercourse more rapidly (both p<0.05). The azoospermia rate was lower in the IVD group than in the NSV group at the third and 12th postoperative months. The rate of contraceptive success based on semen analyses was similar in both groups, especially at the 12th postoperative month (94.3% in the IVD group vs. 98.6% in the NSV group; p=0.054). The IVD group had less risk of complications (i.e. pain, congestive epididymitis and sperm granuloma). More subjects reported satisfaction with IVD sterilization than with NSV. The two procedures were similar in terms of surgical complications. The IVD was slightly less effective, but had a lower risk of later adverse events than the NSV technique. The IVD group also reported a higher level of satisfaction.

Skipping breakfast: gender effects on resting heart rate measures in preadolescents

The cardiovascular response in children to morning nutrition has received little attention, and associated gender-related effects are virtually uninvestigated. This study evaluated resting heart-rate (HR) and heart-rate variability (HRV) in preadolescents after overnight fasting and again after eating a standardized breakfast or continuing to fast. HR increased slightly after eating and decreased significantly with continued fasting. These effects were present for both sexes. Relative to children who ate, those who continued fasting showed increases in HRV-particularly for inter-beat-interval and low frequency component (LF: 0.04-0.15 Hz) measures. Analyses revealed significant increases across variability measures for fasting children, but a selective LF decrease in those who were fed-an effect most prominent in females. Otherwise, males and females showed similar treatment-related changes in HRV. While within-gender comparisons showed similar results for HR, i.e., faster HR in fed compared with fasting males and females, respectively, fasting females-but not males-showed significantly greater increases in variability relative to their fed counterparts. Together, these findings suggest that extended overnight fasting initiates an increase in parasympathetic activity that attenuates the expected increase in cardiovascular output following a mid-morning meal. Observed gender differences were related to greater parasympathetic activity in males and to the apparent emphasis on parasympathetic regulation of LF variability. The implications of these findings for health concerns, the nature of responses to physiological and cognitive stressors, and how such differences may influence performance variables-particularly early in development when cardiovascular responses to these stressors may be more sensitive to nutritional factors-are discussed.

Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI-derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low-resolution metabolite images and multiparametric and regional statistical analysis methods can improve detection of altered metabolite distributions. As a result, full MRSI processing and analysis can involve multiple processing steps and several different data types. In this paper, a processing environment is described that integrates and automates these data processing and analysis functions for imaging of proton metabolite distributions in the normal human brain. The capabilities include normalization of metabolite signal intensities and transformation into a common spatial reference frame, thereby allowing the formation of a database of MR-measured human metabolite values as a function of acquisition, spatial and subject parameters. This development is carried out under the MIDAS project (Metabolite Imaging and Data Analysis System), which provides an integrated set of MRI and MRSI processing functions. It is anticipated that further development and distribution of these capabilities will facilitate more widespread use of MRSI for diagnostic imaging, encourage the development of standardized MRSI acquisition, processing and analysis methods and enable improved mapping of metabolite distributions in the human brain.

Characterization and application of two novel monoclonal antibodies against human OX40: costimulation of T cells and expression on tumor as well as normal gland tissues

OX40, a membrane-bound molecule of the tumor-necrosis-factor-receptor superfamily, is a critical costimulatory receptor during the immune response. Here, we newly generated two specific mouse antihuman OX40 monoclonal antibodies (mAbs) (2G2 and 1F7), whose specificities are quite different from the available OX40 mAb (ACT35) by competition assay. It was also found that both mAbs could enhance the proliferation, activation and differentiation of T lymphocytes primed by anti-CD3 mAb. These results evidenced that both were functional antihuman OX40 mAbs. Furthermore, stained by 2G2 and 1F7, FCM and immunohistochemistry detected the constitutive expression of OX40 on tumor cell lines from epithelium, breast cancer and glioma tissues. Meanwhile, the non-tumor tissues (thyroid gland, stomach gland) were also found OX40 expression. These results suggested that OX40 is not only expressed in activated T cells, but also in some tumors as well as normal gland tissues. Such expression pattern indicated that OX40 may be a valuable surface antigen in unveiling its expression and function outside the immune system. Briefly, these novel antibodies may contribute to the evaluation of the mechanism of tumor metastasis and eventually shed light on further study of tumor immunotherapy and autoimmune diseases.

Evaluation of the effects of dietary fat, conjugated linoleic acid, and ractopamine on growth performance, pork quality, and fatty acid profiles in genetically lean gilts1

An 8-wk study of the effects of CLA, rendered animal fats, and ractopamine, and their interactive effects on growth, fatty acid composition, and carcass quality of genetically lean pigs was conducted. Gilts (n = 228; initial BW of 59.1 kg) were assigned to a 2 x 2 x 3 factorial arrangement consisting of CLA, ractopamine, and fat treatments. The CLA treatment consisted of 1% CLA oil (CLA-60) or 1% soybean oil. Ractopamine levels were either 0 or 10 ppm. Fat treatments consisted of 0% added fat, 5% choice white grease (CWG), or 5% beef tallow (BT). The CLA and fat treatments were initiated at 59.1 kg of BW, 4 wk before the ractopamine treatments. The ractopamine treatments were imposed when the gilts reached a BW of 85.7 kg and lasted for the duration of the final 4 wk until carcass data were collected. Lipids from the belly, outer and inner layers of backfat, and LM were extracted and analyzed for fatty acid composition from 6 pigs per treatment at wk 4 and 8. Feeding CLA increased (P < 0.02) G:F during the final 4 wk. Pigs fed added fat as either CWG or BT exhibited decreased (P < 0.05) ADFI and increased (P < 0.01) G:F. Adding ractopamine to the diet increased (P < 0.01) ADG, G:F, and final BW. The predicted carcass lean percentage was increased (P < 0.05) in pigs fed CLA or ractopamine. Feeding either 5% fat or ractopamine increased (P < 0.05) carcass weight. Adding fat to the diets increased (P < 0.05) the 10th rib backfat depth but did not affect predicted percent lean. Bellies of gilts fed CLA were subjectively and objectively firmer (P < 0.01). Dietary CLA increased (P < 0.01) the concentration of saturated fatty acids and decreased (P < 0.01) the concentration of unsaturated fatty acids of the belly fat, both layers of backfat, and LM. Ractopamine decreased (P < 0.01) the i.m. fat content of the LM but had relatively little effect on the fatty acid profiles of the tissues compared with CLA. These results indicate that CLA, added fat, and ractopamine work mainly in an additive fashion to enhance pig growth and carcass quality. Furthermore, these results indicate that CLA results in more saturated fat throughout the carcass.

Oncogenic Vav1 induces Rac-dependent apoptosis via inhibition of Bcl-2 family proteins and collaborates with p53 deficiency to promote hematopoietic progenitor cell proliferation

Vav1 is an hematopoietic-specific Rho guanine nucleotide exchange factor coupling tyrosine kinase receptors and Rac GTPases, and has been implicated in transformation of fibroblasts and pancreas. To determine the biologic effect and oncogenic potential of Vav1 in hematopoietic lineages, we stably express oncogenic mutant of Vav1 in primary bone marrow cells using retrovirus-mediated gene transfer. Contrary to the growth stimulatory effects observed in fibroblasts, oncogenic Vav1 inhibits hematopoietic stem cell/progenitor engraftment in vivo and progenitor cell expansion in vitro via inducing apoptosis. The oncogenic Vav1-induced apoptosis is associated with reduced expression of Bcl-2 and Bcl-xL proteins and effectively suppressed by transgenic overexpression of Bcl-2, suggesting Vav1-mediated signaling via Bcl-2 in apoptosis. Also, oncogenic Vav1 stimulates sustained activation of Rac GTPases and the biologic effects of oncogenic Vav1 are Rac-dependent. Further, when expressed in the p53-deficient cells, which express elevated Bcl-2 and Bcl-xL and are resistant to the apoptosis, oncogenic Vav1 enhances both proliferation and self-renewal of hematopoietic progenitor cells. These results demonstrate clear phenotypic differences between wild-type and p53(-/-) hematopoietic cells expressing oncogenic Vav1, and suggest oncogenic potential of Vav1-mediated pathways in primary hematopoietic cell when they collaborate with additional genetic hits that affect the p53 pathway.

Lead inhibited N-methyl-D-aspartate receptor-independent long-term potentiation involved ryanodine-sensitive calcium stores in rat hippocampal area CA1

Lead exposure is known to be associated with cognitive dysfunction in children. Impairment of the induction of long-term potentiation (LTP) has been reported in area CA1 of rat hippocampus following lead exposure in vivo and in vitro. The present study was carried out to investigate whether the alterations of N-methyl-d-aspartate (NMDA) receptor-independent LTP following lead exposure involve internal calcium stores in hippocampus CA1 synapses. Monosynaptic field excitatory postsynaptic potentials in hippocampal slice area CA1 were recorded using the whole-cell patch-clamp upon acute lead treatment, and these studies were coupled with calcium imaging experiments to observe internal calcium changes in cultured hippocampal neurons. Inhibiting calcium release by ryanodine significantly reduced NMDA receptor-independent LTP, and depletion of internal calcium stores with thapsigargin blocked this form of LTP. Caffeine, an agonist of ryanodine receptors, enhanced this form of LTP. However, caffeine-enhanced NMDA receptor-independent LTP was depressed after bath application of lead. Moreover, lead further decreased ryanodine- and thapsigargin-reduced NMDA receptor-independent LTP. Calcium imaging also confirmed that lead had an effect on internal calcium release and uptake. Taken together, these results demonstrated that lead inhibited NMDA receptor-independent LTP by action on calcium release and uptake by ryanodine-sensitive stores in rat hippocampal area CA1.

Transhemispheric functional reorganization of the motor cortex induced by the peripheral contralateral nerve transfer to the injured arm

Peripheral nerve injury in a limb usually causes functional reorganization of the contralateral motor cortex. However, a dynamic process of the novel transhemispheric functional reorganization in the motor cortex was found in adult rats after transferring the seventh cervical nerve root from the contralateral healthy side to the injured limb. Initially the ipsilateral motor cortex activated the injured forepaw for 5 months after the operation. Then, both hemispheres of the cortex activated the injured forepaw, and finally the contralateral cortex exclusively controlled the injured forepaw. It is concluded an extensive functional shift occurred between two hemispheres based on neural plasticity in the CNS. The experimental results of the later lesions of the ipsilateral cortex suggest that maintaining transhemispheric functional reorganization does not depend on the corpus callosum, but depends on mechanisms involving central axonal sprouting. Possible mechanisms underlying the alternative changes in cortical functions were discussed in rats and in patients having similar operations.

Risk factors of myelodysplastic syndromes: a case-control study

Little is known about the etiology of myelodysplastic syndromes (MDS). A hospital-based case-control study of 354 adult de novo MDS cases and 452 controls was conducted to investigate associations between lifestyle characteristics and MDS risk. The distribution by French-American-British (FAB) type was 67 (19%) refractory anemia (RA), 38 (11%) refractory anemia with ringed sideroblasts (RARS), 43 (12%) chronic myelomonocytic leukemia (CMML), 136 (38%) RA with excess blasts (RAEB), and 70 (20%) RAEB in transformation (RAEBT). Multivariate logistic regression analyses were performed among all MDS cases and among each FAB type and gender. For all MDS combined, family history of hematopoietic cancer (odds ratio (OR) = 1.92), smoking (OR = 1.65), and exposure to agricultural chemicals (OR = 4.55) or solvents (OR = 2.05) were associated with MDS risk. Among RA/RARS cases, smoking (OR = 2.23) and agricultural chemical exposure (OR = 5.68) were the only risk factors identified. For RAEB/RAEBT cases, family history of hematopoietic cancer (OR = 2.10), smoking (OR = 1.52), and exposure to agricultural chemicals (OR = 3.79) or solvents (OR = 2.71) were independent risk factors. Drinking wine reduced risk for all FAB types by almost 50% (OR = 0.54). We found a joint effect between smoking and chemical exposure with the highest risk among smokers exposed to solvents/agricultural chemicals (OR = 3.22). Results from this large study suggest that several factors play a role in MDS predisposition with possible joint effects. Risk profiles seem to differ by FAB type and gender.

Effects of lead on voltage-gated sodium channels in rat hippocampal CA1 neurons

In this study, the effects of lead (Pb2+) on voltage-gated sodium channel currents (INa) were investigated in acutely dissociated rat hippocampal CA1 neurons using the conventional whole-cell patch-clamp technique. We found that Pb2+ reduced the amplitudes of INa in a concentration-dependent manner, and the effect could be washed out by extracellular application of 3 mM EGTA. The results also showed that at the concentration of 100 microM, Pb2+ decreased the activation threshold and the voltage at which the maximum INa current was evoked and caused negative shifts of INa steady-state activation curve, and enlarged INa tail-currents; Pb2+ induces a left shift of the steady-state inactivation curve, and delayed the recovery of INa from inactivation, and reduced the fraction of available sodium channels; Pb2+ delayed the activation of INa in a concentration- and voltage-dependent manner, and prolonged the time course of the fast inactivation of sodium channels; activity-dependent attenuation of INa was not altered by Pb2+. It was suggested that Pb2+ might exert its effects on sodium channels by binding a specific site on the extracellular side of sodium channels and dragging the IIS4 voltage sensor outwardly. The interaction of Pb2+ with voltage-dependent sodium channels may lead to change in electrical activity and contribute to worsen the neurotoxicological damage.

PAF levels and PAF-AH activities in placentas from normal and preeclamptic pregnancies

OBJECTIVE

The aim of this study was to determine: (1) platelet-activating factor (PAF) levels and PAF-acetylhydrolase (PAF-AH) activities in normal and preeclamptic placentas; (2) lipid peroxide production by placental tissues stimulated with PAF.

METHODS

Placentas were obtained immediately after delivery from normal and preeclamptic pregnancies. Tissue pieces were snap frozen in liquid nitrogen and stored at -70 degrees C. One gram of tissue from each placenta was used for PAF extraction and for total RNA isolation. PAF was measured by PAF [3H] scintillation proximity assay (SPA) system. Trophoblast PAF-AH activity was determined by enzyme-linked immunosorbent assay (ELISA). mRNA expression for PAF receptor was assessed by RNase protection assay (RPA). Normal placental explants were incubated with PAF at concentrations of 1 and 10 microg/ml for 48 h. Lipid peroxide productions of 8-isoprostane and malondialdehyde (MDA) were measured by ELISA and thiobarbituric acid reaction, respectively. Data were presented as mean+/-SE and analyzed by nonparametric Mann-Whitney U test and ANOVA. A p level less than 0.05 was considered statistically significant.

RESULTS

(1) The mean tissue level for PAF was elevated, but not statistically different, in preeclamptic (n=7) than in normal (n=8) placentas, 6.45+/-1.05 versus 4.47+/-0.60 ng/g, p=0.42. (2) PAF-AH activity was higher in trophoblasts from preeclamptic (n=7) placentas than that in trophoblasts from normal (n=8) placentas, 0.69+/-0.16 versus 0.38+/-0.03 micromol/min/microg protein, p<0.05. (3) The relative mRNA expression for PAF receptor was not different between normal (0.70+/-0.08) and preeclamptic (0.76+/-0.13) placental tissues, p=0.60. (4) Productions of 8-isoprostane and MDA were not increased in tissues with PAF in culture, 8-isoprostane: 0.37+/-0.09 ng/mg (control) versus 0.32+/-0.09 ng/mg (1 microg/ml) and 0.37+/-0.07 ng/mg (10 microg/ml), p>0.5; MDA: 0.62+/-0.05 nmol/mg (control) versus 0.68+/-0.04 nmol/mg (1 microg/ml) and 0.69+/-0.03 nmol/mg (10 microg/ml), p>0.5.

CONCLUSIONS

Increased PAF-AH activity in trophoblasts may be a compensatory effect to control PAF level in the preeclamptic placenta. The co-existence of PAF-AH and PAF receptor in trophoblasts suggests an autocrine regulation of PAF in these cells to limit PAF and its metabolites within the placenta.