Metabolic and hormonal effects of oral DHEA in premenopausal women with HIV infection: a randomized, prospective, placebo-controlled pilot study

Women with HIV infection use dehydroepiandrosterone (DHEA) because of its potential effects on mood and energy. We examined the effects of DHEA on the hypothalamic-pituitary-adrenal and gonadal axes and on insulin sensitivity. Fifteen HIV-positive women were randomized to receive placebo (6 subjects) or oral DHEA (9 subjects). ACTH-, CRF-, and GnRH-stimulation tests were performed before and after 8 weeks of treatment. DHEA, DHEA-S, dihydrotestosterone, total testosterone, free testosterone, sex hormone-binding globulin, estrone, estradiol, cortisol, insulin, IGF-1, IGFBP-1, IGFBP-3, and adiponectin in plasma or serum were measured. There was a significant increase in DHEA (p<0.004), DHEA-S (p<0.008), total testosterone (p<0.008), dihydrotestosterone (p<0.004), androstenedione (p<0.04), and estrone (p<0.03) from baseline within the DHEA group but not within the placebo group. There was a significant increase in DHEA (p<0.0006), DHEA-S (p<0.032), total testosterone (p<0.01), and dihydrotestosterone (p<0.005) in the DHEA group compared with the placebo group. Oral DHEA produces significant increases in circulating DHEA, DHEA-S, testosterone, DHT, and, possibly, androstenedione and estrone levels in premenopausal women with HIV infection. In the current pilot study these hormone changes did not affect the pituitary or adrenal axis or insulin/IGF indices. Long-term studies with larger groups of patients are needed to confirm these data and to determine their clinical significance.

Diadenosine pentaphosphate is a potent activator of cardiac ryanodine receptors revealing a novel high-affinity binding site for adenine nucleotides

BACKGROUND AND PURPOSE

Diadenosine polyphosphates are normally present in cells at low levels, but significant increases in concentrations can occur during cellular stress. The aim of this study was to investigate the effects of diadenosine pentaphosphate (Ap5A) and an oxidized analogue, oAp5A on the gating of sheep cardiac ryanodine receptors (RyR2).

EXPERIMENTAL APPROACH

RyR2 channel function was monitored after incorporation into planar bilayers under voltage-clamp conditions.

KEY RESULTS

With10 micromol.L(-1) cytosolic Ca2+, a significant 'hump' or plateau at the base of the dose-response relationship to Ap5A was revealed. Open probability (Po) was significantly increased to a plateau of approximately 0.2 in the concentration range 100 pmol x L(-1)-10 micromol x L(-1). High Po values were observed at >10 micromol x L(-1) Ap5A, and Po values close to 1 could be achieved. Nanomolar levels of ATP and adenosine also revealed a hump at the base of the dose-response relationships, although GTP did not activate at any concentration, indicating a common, high-affinity binding site on RyR2 for adenine-based compounds. The oxidized analogue, oAp5A, did not significantly activate RyR2 via the high-affinity binding site; however, it could fully open the channel with an EC(50) of 16 micromol.L(-1) (Ap5A EC(50) = 140 micromol x L(-1)). Perfusion experiments suggest that oAp5A and Ap5A dissociate slowly from their binding sites on RyR2.

CONCLUSIONS AND IMPLICATIONS

The ability of Ap5A compounds to increase Po even in the presence of ATP and their slow dissociation from the channel may enable these compounds to act as physiological regulators of RyR2, particularly under conditions of cellular stress.

Concentration control of carbon nanotubes in aqueous solution and its influence on the growth behavior of fibroblasts

This work investigated the biological influence of water-soluble multiwalled carbon nanotubes (wsMWCNTs) on fibroblast cell growth as a function of concentration control in an aqueous solution. The wsMWCNTs were prepared by an optimal procedure of ultrasonication/concentrated acids oxidation. The concentration of wsMWCNT in the solution was quantified by an established calibration line. A stable concentration of 0.3mg/ml was obtained in the surfactant-free water. The physicochemical properties of wsMWCNTs were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV/VIS/NIR spectroscopy, and dynamic light scattering (DLS). Cell proliferation and the cell cycle were examined by MTS assay, flow cytometry and TEM respectively. Experimental results showed that the oxidation degree was a key factor that determined the concentration and stability of wsMWCNTs in the aqueous solution. The wsMWCNTs were able to enter into the cells and mainly accumulated in the cytoplasm. The wsMWCNTs-induced variations in cell proliferation and the cell cycle were concentration dependent. Cells cultivated with wsMWCNTs of 0.3mg/ml underwent a dramatic apoptosis. The proliferation was clearly suppressed when the cells were cultivated with wsMWCNTs of 0.03 mg/ml. There were no obvious influences on cell proliferation and the cell cycle when the concentration of wsMWNTs decreased to 0.01 mg/ml.

Genotyping of Chlamydophila psittaci strains derived from avian and mammalian species

Eleven Chlamydophila (formerly Chlamydia) psittaci strains derived from avian and mammalian species (two from dairy cows, one from duck, three from sheep, three from wild birds, and two from pigs) were identified as genotype C by outer membrane protein A gene sequencing. Genotype C had been preferentially associated with waterfowl. This paper suggests that mammals may represent an underestimated source for genotype C strains and for human psittacosis cases.

Natural killer cells suppress full cycle HCV infection of human hepatocytes

The role of natural killer (NK) cells in controlling hepatitis C virus (HCV) infection and replication has not been fully delineated. We examined NK cell-mediated noncytolytic effect on full cycle HCV infection of human hepatocytes. Human hepatocytes (Huh7.5.1 cells) co-cultured with NK cells or treated with supernatants (SN) from NK cells cultures had significantly lower levels of HCV RNA and protein than control cells. This NK cell-mediated anti-HCV activity could be largely abolished by antibody to interferon-gamma (IFN-gamma). The investigation of the mechanisms for NK cell-mediated anti-HCV activity showed that NK SN-treated hepatocytes expressed higher levels of IFN-alpha/beta than the control cells. NK SN also enhanced IFN regulatory factor-3 and 7 expression in the hepatocytes. In addition, NK SN enhanced the expression of signal transducer and activator of transcription 1 and 2, the nuclear factors that are essential for the activation of IFN-mediated antiviral pathways. These data provide direct evidence at cellular and molecular levels that NK cells have a key role in suppressing HCV infection of and replication in human hepatocytes.

Realtime photoacoustic microscopy of murine cardiovascular dynamics

Non-invasive visualization of cardiovascular dynamics in small animals is challenging due to their rapid heart-rates. We present a realtime photoacoustic imaging system consisting of a 30-MHz ultrasound array transducer, receive electronics, a high-repetition-rate laser, and a multicore-computer, and demonstrate its ability to image optically-absorbing structures of the beating hearts of young athymic nude mice at rates of approximately 50 frames per second with 100 microm x 25 microm spatial resolution. To our knowledge this is the first report of realtime photoacoustic imaging of physiological dynamics.

Realtime photoacoustic microscopy of murine cardiovascular dynamics

Non-invasive visualization of cardiovascular dynamics in small animals is challenging due to their rapid heart-rates. We present a realtime photoacoustic imaging system consisting of a 30-MHz ultrasound array transducer, receive electronics, a high-repetition-rate laser, and a multicore-computer, and demonstrate its ability to image optically-absorbing structures of the beating hearts of young athymic nude mice at rates of approximately 50 frames per second with 100 microm x 25 microm spatial resolution. To our knowledge this is the first report of realtime photoacoustic imaging of physiological dynamics.

Identification of an antiapoptotic protein complex at death receptors

Stimulation of death receptors activates the extrinsic apoptotic signaling pathway that leads to cell death. Although many steps of this apoptotic signaling cascade are known, few mechanisms that counterbalance the death signal have been described. We identified an antiapoptotic protein complex associated with death receptors that contains glycogen synthase kinase-3 (GSK3), DDX3 and cellular inhibitor of apoptosis protein-1 (cIAP-1). GSK3, DDX3 and cIAP-1 are associated in cells with each other and with death receptors. Blocking the actions of GSK3 or DDX3 potentiated caspase-3 activation induced by stimulation of four different death receptors in several types of cells. GSK3 restrained apoptotic signaling by inhibiting formation of the death-inducing signaling complex and caspase-8 activation. Stimulated death receptors surmount the antiapoptotic complex by causing GSK3 inactivation and cleavage of DDX3 and cIAP-1 to enable progression of the apoptotic signaling cascade, but the antiapoptotic complex remains functional in cancer cells resistant to death receptor stimulation, a resistance that is overcome by GSK3 inhibitors. Thus, an antiapoptotic complex of GSK3, DDX3 and cIAP-1 caps death receptors, providing a checkpoint to counterbalance apoptotic signaling.

The cloning and expression of alpha-tubulin in Monochamus alternatus

The Japanese pine sawyer Monochamus alternatus is one of the major forest pests. It damages pine directly and transfers the nematode Bursaphelenchus xylophilus to pine wood; resulting in serious economic losses around the world every year. Alpha-tubulin is one of most important proteins in most species. We cloned a ubiquitously expressed M. alternatus alpha-tubulin gene and analysed its nucleotides and protein structure; its sequence characters are consistent with what have been reported in other insects. The alignment of proteins showed that there is high homology of alpha-tubulin between M. alternatus and other species. Western blot and immunocytochemistry analyses suggested a common epitope of alpha-tubulin between M. alternatus and Strongylcentrotus purpuratus. We also expressed the protein in Escherichia coli for further functional studies.

Effects of the polysaccharide fraction of Urtica fissa on castrated rat prostate hyperplasia induced by testosterone propionate

A crude polysaccharide fraction of Urtica fissa roots and stems (UFP) was obtained by water extraction and ultrafiltration, and its effect on castrated rat prostate hyperplasia induced by testosterone propionate was evaluated by the volume index, wet and dry weight index and histopathological tests. Results showed that the crude polysaccharide fraction significantly inhibited prostatic hyperplasia in animal models at doses of 62.5, 125, 250 mg/kg body wt. (administered orally). Treatment with UFP at 62.5 mg/kg body wt. decreased the volume index by 32%, the wet weight index by 17% and the dry weight index by 23%, respectively. In the high-dose group (UFP at 250 mg/kg body wt.), the indexes of volume, wet weight and dry weight decreased further by 37%, 25% and 33%, respectively. Histopathological examination showed that proliferation of prostatic epithelial cells and fibrotic tissues were significantly inhibited.

Mechanisms underlying B-cell tolerance induction by antigen-immunoglobulin G gene transfer

Previous studies on the mechanisms underlying tolerance induction in diabetes have mainly focused on T cells, however B cells also have an important role in diabetes. Based on our previous studies that splenocytes, transduced with glutamic acid decarboxylase (GAD) 65 fused to immunoglobulin (Ig) G carrier, reduced antibody-mediated response in non-obese diabetic (NOD) mice, here we examined the mechanisms underlying B-cell tolerance in this system. We found that GAD-IgG-transduced splenocytes did not reduce CD40 expression on B-cells in NOD mice, but they did downregulate CD40 ligand (CD40L) expression. Furthermore, anti-CD40L injection reduced autoantibody levels in NOD mice and in vitro experiments demonstrated that CD40L blockade reduced the antigenpresenting capability of B-cells. In conclusion, the results of this study suggest that downregulation of CD40L may be one mechanism underlying the induction of B-cell tolerance in GAD-IgG-treated NOD mice.

Down-regulation of norepinephrine transporter expression on membrane surface induced by chronic administration of desipramine and the antagonism by co-administration of local anesthetics in mice

We have previously shown that chronic administration of the antidepressant desipramine, a norepinephrine transporter (NET) inhibitor to mice markedly enhanced convulsions induced by local anesthetics and that behavioral sensitization may be relevant to decreased [(3)H]norepinephrine uptake by the isolated hippocampus. The co-administration of local anesthetics with desipramine reversed the behavioral sensitization and down-regulation of NET function induced by desipramine. The present study aimed to elucidate whether chronic treatment with desipramine regulates the expression of NET protein examined in membrane fractions in various brain regions and whether co-administration of local anesthetics affects the desipramine-induced alteration of NET expression. Desipramine with or without local anesthetics was injected intraperitoneally once a day for 5 days. The animals were decapitated 48 h after the last administration of drugs and the whole cell fraction, membrane fraction and cell-surface protein fraction were prepared. [(3)H]nisoxetine binding was significantly reduced in the P2 fraction of the hippocampus by chronic administration of desipramine, and the reduction was overcome by co-administration of lidocaine with desipramine. Immunoreactive NET was detected by SDS-PAGE and immunoblotting in the murine hippocampus. NET protein expression in the whole cell fraction and membrane fraction was not affected by treatment with any drugs. However, administration of desipramine significantly reduced the amount of immunoreactive NET in the cell-surface protein fraction. This reduction was blocked by simultaneous injection of lidocaine, bupivacaine or tricaine. These results indicate that the NET down-regulation indicated by the reduction of [(3)H]nisoxetine binding was induced by administration of desipramine via decrease of NET localization on the cell surface. The antagonistic actions of local anesthetics against NET down-regulation by desipramine were related to alterations of the cell-surface localization of NET.

Mechanisms of regulatory T-cell induction by antigen-IgG-transduced splenocytes

Our previous studies have demonstrated that splenocytes, transduced with glutamate decarboxylate 65 (GAD) and IgG fusion construct, protect non-obese diabetes (NOD) mice from diabetes. However, the mechanism by which this strategy prevents diabetes is not well understood. Here, we found that CD4(+)Foxp3(+)Treg cells, in vitro induced by GAD-IgG-transduced splenocytes, after transfer, were responsible for prevention of diabetes in NOD mice. Further studies suggested that GAD-IgG-transduced B cells could secrete high level of TGF-beta and stimulated CD4(+)T cells to secrete high level of IFN-gamma. Finally, we found that when TGF-beta and/or IFN-gamma were blocked, CD4(+)Foxp3(-)T cells were not converted into CD4(+)Foxp3(+)Treg cells. The results suggest that GAD-IgG-transduced B cells via TGF-beta and IFN-gamma in vitro induce the CD4(+)Foxp3(+)Treg cells which are responsible for prevention of diabetes in NOD mice by GAD-IgG-gene transfer.

Targeting SPARC expression decreases glioma cellular survival and invasion associated with reduced activities of FAK and ILK kinases

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular glycoprotein expressed in several solid cancers, including malignant gliomas, upon adoption of metastatic or invasive behaviors. SPARC expression in glioma cells promotes invasion and survival under stress, the latter process dependent on SPARC activation of AKT. Here we demonstrate that downregulation of SPARC expression with short interfering RNA (siRNA) in glioma cells decreased tumor cell survival and invasion. SPARC siRNA reduced the activating phosphorylation of AKT and two cytoplasmic kinases, focal adhesion kinase (FAK) and integrin-linked kinase (ILK). We determined the contributions of FAK and ILK to SPARC effects using SPARC protein and cell lines engineered to overexpress SPARC. SPARC activated FAK and ILK in glioma cells previously characterized as responsive to SPARC. Downregulation of either FAK or ILK expression inhibited SPARC-mediated AKT phosphorylation, and targeting both FAK and ILK attenuated AKT activation more potently than targeting either FAK or ILK alone. Decreased SPARC-mediated AKT activation correlated with a reduction in SPARC-dependent invasion and survival upon the downregulation of FAK and/or ILK expression. These data further demonstrate the role of SPARC in glioma tumor progression through the activation of intracellular kinases that may provide novel therapeutic targets for advanced cancers.

A frequent Y chromosome b2/b3 subdeletion shows strong association with male infertility in Han-Chinese population

BACKGROUND

Azoospermia factor c (AZFc) subdeletions were reported to be significant risk factors for spermatogenesis. In this study, we assessed the occurrence of classical AZF deletions and AZFc subdeletions and their impact on male infertility in a Han-Chinese population.

METHODS

This study analysed a population of 699 subjects, including 451 idiopathic infertile patients with a range of fertility disorders and 248 fertile controls, using a retrospective design. Deletions were identified by multiplex PCR.

RESULTS

The prevalence and phenotypes of the classical AZF deletions were similar to previous studies. Subdeletions of the AZFc region in patients showed similar overall frequencies in all sperm concentration categories of gr/gr (7.0%) and b2/b3 (8.9%). For controls, these subdeletions were also found with a prevalence of gr/gr (7.7%) and b2/b3 (3.2%). b1/b3 deletions were not found either in the patients or in the controls.

CONCLUSION

Our data showed a higher frequency of deletion events in this Han-Chinese population than in populations elsewhere in the world. The classical AZF deletions were the primary genetic factors for spermatogenic failure, while no significant association was found for AZFc subdeletions with sperm concentration. However, the b2/b3 subdeletion was significantly associated with idiopathic male infertility (odds ratio, 2.93; 95% confidence interval 1.34-6.39) (P = 0.005), indicating a potential impairment of male fertility.

Differential expression of litchi XET genes in relation to fruit growth

Xyloglucan endotransglycosylase (XET) catalyses the transglycosylation of xyloglucan, the major hemicellulose polymer, which has been thought to mediate the cross-linking of cellulose microfibrils in cellular walls and proposed to be involved in the control of cell wall relaxation. To understand the relationship between litchi fruit cracking and gene expression patterns, three XET genes from litchi fruit were identified and then examined for their expression profiles in pericarp and aril tissues at different development stages, using a cracking-resistant cultivar, 'Huaizhi', and a cracking-susceptible cultivar, 'Nuomici'. Three full-length cDNAs of 1267, 1095 and 1156 bp encoding XETs, named LcXET1, LcXET2 and LcXET3, respectively, were isolated from expanding fruit using RT-PCR and RACE-PCR (rapid amplification of cDNA ends) methods. Northern blotting analysis showed that LcXET1 mRNA accumulation occurred much earlier in aril tissues at 59 days after anthesis (DAA) than in pericarp tissues at 73 DAA in 'Nuomici'. However, it appeared at almost the same time (66 DAA) in pericarp and aril tissues in 'Huaizhi', which suggested that differential accumulation of LcXET1 in pericarp and aril tissues in 'Nuomici' and 'Huaizhi' was closely associated with fruit cracking. LcXET2 mRNA accumulation could be detected in pericarp and aril tissues throughout fruit development but exhibited a differential accumulation pattern between pericarp and aril tissues. In the aril of 'Nuomici', intensive signal bands were detectable at 59-73 DAA in rapidly expanding fruits of 'Nuomici' but only weak bands could be found in the pericarp tissues. In contrast, moderate signal bands were detectable both in pericarp and aril tissues of 'Huaizhi' fruits. Furthermore, LcXET3 showed constitutive expression in both pericarp and aril tissues of developing 'Nuomici' and 'Huaizhi' litchi fruit. In addition, differential expression patterns of three XETs genes were observed in different tissues of litchi, with only LcXET1 being fruit-specific. To further address the role of LcXET in fruit cracking, alpha-naphthalene acetic acid (NAA) was used to treat 'Nuomoci' to reduce fruit cracking. Enhanced LcXET1 mRNA accumulation appeared in pericarp while LcXET2 and LcXET3 mRNA accumulation enhanced in aril tissues in the NAA-treated fruits. Thus, LcXET1 is more likely to play a role in reducing litchi fruit cracking than LcXET2 and LcXET3.

Periodic ZnO nanorod arrays defined by polystyrene microsphere self-assembled monolayers

We demonstrate a low-cost and effective method to fabricate hexagonally patterned, vertically aligned ZnO nanorod arrays. Selective wet-etching is used to develop the catalyzing gold particle hexagonal pattern with the aid of a polystyrene microsphere self-assembled monolayer. The gold particles have tunable sizes independent of the polystyrene microsphere's diameter and are inherently round in shape. Each ZnO rod is grown individually from a catalyzing site via catalyst-initiated epitaxy, and the original hexagonal periodicity is well-preserved. The rods have flat ends, and the diameters of the rods can be controlled well by the amount of source materials. This method provides a promising way to create ZnO one-dimensional nanostructures for applications as two-dimensional photonic crystal, sensor arrays, nanolaser arrays, and optoelectronic devices.