Age-associated differences in the inhibition of mitochondrial permeability transition pore opening by cyclosporine A

BACKGROUND

Inhibiting mitochondrial permeability transition pore (mPTP) opening is a key protection of the myocardium from ischemia/reperfusion (I/R) injury. Here, we investigated age-associated differences in the ability of cyclosporine A (CsA) to protect the heart and to modulate mPTP opening during I/R injury in vivo and its opening induced by reactive oxygen species (ROS) in vitro.

METHODS

Fischer 344 male rats were assigned from their respective age groups, young or old groups, to (1) I/R or (2) I/R+CsA. All animals were subjected to 30 min of ischemia following 120 min of reperfusion to determine myocardial infarct size in vivo. To measure mPTP opening in vivo, left ventricular tissues were collected 10 min after reperfusion and nicotinamide adenine dinucleotide (NAD(+)) levels were measured. In parallel experiments, rat ventricular myocytes were prepared from young and old hearts, loaded with tetramethylrhodamine ethylester and then subjected to oxidative stress in the presence or absence of CsA, and the mPTP opening time was measured using laser scanning confocal microscopy.

RESULTS

CsA reduced myocardial infarct size in young I/R rats. Whereas CsA failed to significantly affect myocardial infarct size in old I/R rats, NAD(+) levels were better preserved in young CsA-treated rats, but this relative improvement was not observed in old rats. CsA also significantly prolonged the time necessary to induce mPTP opening in young cardiomyocytes, but not in cardiomyocytes isolated from the old rats.

CONCLUSIONS

mPTP regulation is dysfunctional in the aged myocardium and this could account for loss of cardioprotection with aging.

High resolution transmission electron microscope observation of zero-strain deformation twinning mechanisms in Ag

We have observed a new deformation-twinning mechanism using the high resolution transmission electron microscope in polycrystalline Ag films, zero-strain twinning via nucleation, and the migration of a Σ3{112} incoherent twin boundary (ITB). This twinning mechanism produces a near zero macroscopic strain because the net Burgers vectors either equal zero or are equivalent to a Shockley partial dislocation. This observation provides new insight into the understanding of deformation twinning and confirms a previous hypothesis: detwinning could be accomplished via the nucleation and migration of Σ3{112} ITBs. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.

Protective role of HO-1 for alcohol-dependent liver damage

BACKGROUND/AIMS

Alcoholic liver disease is continuously increasing in developed countries being a leading cause of death worldwide. Chronic ethanol consumption induces oxidative stress by accumulation of reactive oxygen intermediates (ROI) while reducing the cellular antioxidant defense. Induction of heme oxygenase-1 (HO-1) may protect primary human hepatocytes (hHeps) from such damage. Thus, the aim of this study was to investigate the potential of polyphenols to protect hHeps from ethanol-dependent oxidative damage.

METHODS

hHeps were isolated by collagenase perfusion. ROI and cellular glutathione (GSH) were measured by fluorescent-based assays. Cellular damage was determined by lactate dehydrogenase (LDH) leakage and staining for apoptosis and necrosis. Nuclear translocation of Nrf2 and HO-1 expression were analyzed by Western blot.

RESULTS

Ethanol and TGF-β rapidly increase ROI and reduce GSH in hHeps, causing apoptosis with a release of approximately 40% total LDH after 72 h. Similar to incubation with hemin preincubation and co-incubation of cells with nifedipine, verapamil and quercetin significantly reduce oxidative stress and resulting cellular damage, in a dose-dependent manner, by initiating nuclear translocation of Nrf2 which in turn induces HO-1 under the control of p38 and ERK. Blocking of HO-1 activity with ZNPP9 reverses the protective effect of all three substances.

CONCLUSION

Our results suggest that increasing HO-1 activity in hHeps protects them from oxidative stress-dependent damage. As polyphenols have great potential to induce HO-1 expression, they may play an important role for future therapeutic strategies to protect liver from oxidative stress-dependent damage observed during chronic alcohol consumption.

Pharmacokinetics of verapamil in diabetic rats induced by combination of high-fat diet and streptozotocin injection

The aim of this study was to investigate effects of type 2 diabetes on the pharmacokinetics of verapamil after intravenous administration. Diabetes mellitus (DM) rats were induced by combination of high-fat diet (HFD) and streptozotocin. Plasma concentrations of verapamil in DM rats, rats fed with HFD, and control (CON) rats were measured after intravenous administration of 1 mg/kg verapamil and corresponding pharmacokinetic parameters were estimated. Area under the plasma concentration in DM rats was significantly smaller than that in CON rats. In vitro microsomal study showed that intrinsic clearance of verapamil in DM rats was significantly higher than those in CON rats. Compared to CON rats, higher intrinsic clearance was also observed in HFD rats. Western blot results demonstrated higher levels of CYP3A2 in DM and HFD rats, which was in line to activity of CYP3A. All the results gave a conclusion that diabetes may enhance metabolism of verapamil in rat, and the enhancement may partly result from induction of CYP3A.

A clinical case-control study on the association between mannose-binding lectin and susceptibility to HIV-1 infection among northern Han Chinese population

Mannose-binding lectin (MBL) is a key molecule of the innate immune system and a competent to bind carbohydrates of a variety of microorganisms, resulting in complement activation and opsonophagocytosis against various pathogens. However, there is no systemic investigation on the MBL's role in innate immune responses against HIV-1 infection among northern Han Chinese. This study investigated the association between MBL and HIV-1 infection susceptibility among northern Han Chinese. A total of 91 HIV-1 infected patients and 91 HIV-1 seronegative healthy individuals were recruited. Six polymorphisms of MBL2 gene were genotyped by pyrosequencing. The quantitative measurement of serum MBL concentration and MBL complex activity were performed by ELISA. The CD4+ T-cell counts were determined by flow cytometry. The plasma viral loads of 91 HIV-1 infected patients were determined by bDNA method. The results show that there is an association between MBL and HIV-1 infection susceptibility among northern Han Chinese. The individuals with B variant, low serum MBL concentration and low MBL complex activity are more susceptible to HIV-1 infection.

Surface Morphology and Composition Characterization at the Initial Stages of AlN Crystal Growth

The morphology and composition of AlN crystals on 6H-SiC (0001) at the initial stage of crystal growth by sublimation re-condensation technique were investigated by SEM and SAM. Discontinuous AlN coverage occurred after 15 minutes growth. The AlN nuclei size, and growth rate increased as temperature increased or pressure decreased. The SiC substrate decomposed leaving hexagonal hillocks; simultaneously, the AlN nucleated on these SiC hillocks apparently rotated by 15° to 30°. The chemical composition of the substrate and different AlN crystal facets were characterized by SAM. The bare substrate area was stoichiometric SiC with insignificant conversion to silicon nitride, while Si and C preferentially incorporated in the AlN at the initial stages of growth on specific crystal planes.

Association of the glucocerebrosidase N370S allele with Parkinson's disease in two separate Chinese Han populations of mainland China

BACKGROUND AND PURPOSE

Mutations in the glucocerebrosidase (GBA) gene have been implicated in the development of Parkinson's disease (PD). However, recent screenings for GBA mutations in PD subjects from different ethnic populations have yielded contradictory results.

METHODS

We performed a case-control study to look for a possible association between PD and the GBA N370S allele involving 628 subjects in two separate Chinese Han populations from mainland China. All subjects were successfully genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

A total of six patients with PD and two control subjects carried the N370S allele. Although PD cases (1.8%) had an increased frequency of N370S compared to controls (0.7%), the difference was not statistically significant (P = 0.290). However, when PD cases were stratified by age at onset, a higher frequency of N370S in late-onset PD (LOPD) cases (3.2%) compared to controls was observed.

CONCLUSIONS

Our results suggest that the N370S allele might be associated with LOPD in Chinese Han population and that this phenomenon should be further examined in a larger study.

Oestrogen receptor-alpha polymorphism and risk of fracture: a meta-analysis of 13 studies including 1279 cases and 6069 controls

A meta-analysis was performed to evaluate the effect of oestrogen receptor-alpha (ESR1) gene PvuII polymorphism on fracture risk. It included published data from relevant studies (up to May 2010) identified from Medline, Embase and Current Contents. The 13 included studies contained 1279 fracture cases and 6069 controls. The combined results based on these studies showed no relationship between ESR1 gene PvuII polymorphism and fracture risk. No significant difference in genotype distribution was found when stratifying by race. When stratifying by fracture type, it was found that vertebral fracture cases had a significantly higher frequency of the PvuII pp genotype than controls in five studies (552 cases and 2350 controls). This meta-analysis suggests a modest but statistically significant association between the ESR1 PvuII pp genotype and vertebral fracture.

In Vivo Stress Analysis of a Pacing Lead From an Angiographic Sequence

In this paper, a method is presented to analyze the mechanical stress distribution in a pacing lead based on a sequence of paired 2D angiographic images. The 3D positions and geometrical shapes of an implanted pacemaker lead throughout the cardiac cycle were generated using a previously validated 3D modeling technique. Based on the Frenet–Serret formulas, the kinematic property of the lead was derived and characterized. The distribution of curvature and twist angle per unit length in the pacing lead was calculated from a finite difference method, which enabled a rapid and effective computation of the mechanical stress in the pacing lead. The analytical solution of the helix deformation geometry was used to evaluate the accuracy of the proposed numerical method, and an excellent agreement in curvature, twist angle, and stresses was achieved. As demonstrated in the example, the proposed technique can be used to analyze the complex movement and deformation of the implanted pacing lead in vivo. The information can facilitate the future development of pacing leads.

Genetic diversity of mitochondrial cytochrome b gene in Chinese native buffalo

The origins of the domestic water buffalo remain contentious. To better understand the origins of Chinese water buffalo, we sequenced the complete mitochondrial cytochrome b (MT-CYB) gene from 270 individuals representing 13 Chinese domestic swamp buffalo populations. We found genetic evidence of introgression of river buffalo into Chinese swamp buffalo herds. Swamp buffalo haplotypes can be divided into two highly divergent lineages (A and B), suggesting that Chinese native swamp buffalo have two maternal origins. We found that the A→G transition in the buffalo MT-CYB gene stop codon resulted in buffalo haplotypes being terminated by one of two stop codons: AGA or AGG. AGA is common to river buffalo and lineage A of swamp buffalo, while AGG is specific to lineage B of swamp buffalo. Lineage A appears to have been domesticated in China. Further genetic evidence is required to clarify the origins of lineage B.

Value of CYP3A5 genotyping on determining initial dosages of tacrolimus for Chinese renal transplant recipients

Optimal blood levels of tacrolimus in transplant recipients are critically important to preserve the allograft. Suboptimal doses of the immunosuppressant can result in allograft toxicity or rejection. In the present study, we determined CYP3A5 genotypes of patients and analyzed their medical documents in 2 successive periods. In the first period, a fixed initial dosage of 0.1 mg/kg was prescribed daily for 28 patients regardless of their CYP3A5 genotype. In the second period, CYP3A5 genotyping was performed with polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing. The frequency distribution of CYP3A5 genotypes was 47.4% (38/78) for *1/*3, 2.6% (2/78) for *1/*1, and 50% (39/78) for *3/*3. The patients with *1/*3 had shown significantly lower tacrolimus blood levels than those with the *3/*3 when the initial dose of 0.10 mg/kg was given for 2 weeks postoperatively. In the second period, initial dosages were selected according to individuals' CYP3A5 genotypes, 0.08 mg/kg/d for recipients with CYP3A5 *3/*3 and 0.15 mg/kg/d for recipients with *1/*3. Adjustment of the initial dosage of tacrolimus was documented to improve the proportion of patients achieving target drug blood levels in the early postoperative stage: from 46.7% to 81.8% of the *1/*3 group and from 46.2% to 73.1% of the *3/*3 group on the third day. In conclusion, CYP3A5 polymorphism plays an important role in influencing tacrolimus blood levels. Initial tacrolimus dosage selection based on CYP3A5 genotyping can improve drug blood levels in the early stage following renal transplantation.

A B2 SINE insertion in the Comt1 gene (Comt1(B2i)) results in an overexpressing, behavior modifying allele present in classical inbred mouse strains

Catechol-O-methyltransferase (COMT) is a key enzyme for dopamine catabolism and COMT is a candidate gene for human psychiatric disorders. In mouse it is located on chromosome 16 in a large genomic region of extremely low variation among the classical inbred strains, with no confirmed single nucleotide polymorphisms (SNPs) between strains C57BL/6J and DBA/2J within a 600-kB window. We found a B2 SINE in the 3′ untranslated region (UTR) of Comt1 which is present in C57BL/6J (Comt1^B2i) and other strains including 129 (multiple sublines), but is not found in DBA/2J (Comt1⁺) and many other strains including wild-derived Mus domesticus, M. musculus, M. molossinus, M.castaneus and M. spretus. Comt1^B2i is absent in strains closely related to C57BL/6, such as C57L and C57BR, indicating that it was polymorphic in the cross that gave rise to these strains. The strain distribution of Comt1^B2i indicates a likely origin of the allele in the parental Lathrop stock. A stringent association test, using 670 highly outbred mice (Boulder Heterogeneous Stock), indicates that this insertion allele may be responsible for a difference in behavior related to exploration. Gene expression differences at the mRNA and enzyme activity level (1.7-fold relative to wild type) indicate a mechanism for this behavioral effect. Taken together, these findings show that Comt1^B2i (a B2 SINE insertion) results in a relatively modest difference in Comt1 expression and enzyme activity (comparable to the human Val-Met polymorphism) which has a demonstrable behavioral phenotype across a variety of outbred genetic backgrounds.

Preparation and lithium storage performances of mesoporous Fe₃O₄@C microcapsules

Fe(3)O(4)@C microcapsules were prepared using carbon-coated α-FeOOH nanorods as precursors, which were synthesized via two-step hydrothermal reactions. During the subsequent sintering procedure, α-FeOOH was reduced to Fe(3)O(4) by carbon, accompanied by the formation of mesopores. In Fe(3)O(4)@C microcapsules, mesoporous Fe(3)O(4) nanorods are coated with amorphorous carbon layers. The Fe(3)O(4)/C composites with such special structures demonstrate high specific capacity and good cyclic stability as anode materials in Li test cells.

Inhibition of p38 mitogen-activated protein kinase promotes ex vivo hematopoietic stem cell expansion

Hematopoietic stem cell (HSC) self-renewal is tightly regulated by a complex crosstalk between many cell-intrinsic regulators and a variety of extrinsic signals from the stem cell niche. In this study, we examined whether the p38 mitogen-activated protein kinase (p38) is one of the intrinsic regulators that can negatively regulate HSC self-renewal in vitro and whether inhibition of p38 activity with a small molecule inhibitor can promote HSC expansion ex vivo. The results from this study showed that sorted mouse bone marrow Lin(-)Sca1(+)c-kit(+) cells (LSK(+) cells) exhibited selective activation of p38 after culture in a serum-free medium supplemented with 100 ng/mL stem cell factor, thrombopoietin, and Flt3 ligand. The activation of p38 was associated with a significant reduction in HSCs and induction of apoptosis and cellular senescence in LSK(+) cells and their progeny. Addition of the specific p38 inhibitor SB203580 (SB, 5 μM) to the culture inhibited the activation of p38 in LSK(+) cells, which led to increase in HSC self-renewal and ex vivo expansion as shown by the cobblestone area forming cell assay, competitive repopulation, and serial transplantation. The increase in HSC expansion is likely attributable to SB-mediated inhibition of HSC apoptosis and senescence and upregulation of HoxB4 and CXCR4. These findings suggest that p38 plays an important role in the regulation of HSC self-renewal in vitro and inhibition of p38 activation with a small molecule inhibitor may represent a novel approach to promote ex vivo expansion of HSCs.

Features of Hirayama Disease on Fully Flexed Position Cervical MRI

This study reports on cervical magnetic resonance imaging (MRI) performed in the fully flexed position in 13 male patients with Hirayama disease and 12 normal controls (males). The anterior–posterior diameter of the cervical cord at the superior margin of the C6 vertebral body was measured, as well as the angle between adjacent cervical bodies. Localized lower cervical-cord atrophy, cord flattening and abnormal signals in the posterior epidural space were studied. Patients demonstrated an increased angle between C5 and C6, and C6 cord lesions. There were significant differences between patients and controls in localized lower cervical-cord atrophy and cord flattening. Many patients were found to have a crescent-shaped high-intensity mass on T2WI MRI and a low-intensity mass on T1WI MRI in the posterior epidural space. In patients, there were specific imaging features of Hirayama disease on fully flexed MRI. Cervical MRI in the fully flexed position has significant value in the clinical diagnosis of Hirayama disease.

Transcription factors BmPOUM2 and BmβFTZ-F1 are involved in regulation of the expression of the wing cuticle protein gene BmWCP4 in the silkworm, Bombyx mori

In Bombyx mori, the wing cuticle protein gene BmWCP4 is expressed specifically in the epidermis at the onset and mid-stage of pupation and is responsible for the formation of the pupal cuticle during the larval-pupal metamorphosis. The gene consists of four exons and three introns and is present as a single copy in the genome. Its expression was up-regulated by 20-hydroxyecdysone (20E) and the 20E-induced expression was suppressed by juvenile hormone (JH) III. The upstream regulatory sequence region of the BmWCP4 gene was cloned and the regulatory elements responsible for 20E induction were identified. Two cis-regulatory elements (CREs) bound by the transcription factors BmPOUM2 and BmβFTZ-F1 were identified that mediated 20E-regulated expression of this gene. An electrophoretic mobility shift assay detected two nuclear proteins isolated from the epidermis and the BmN cell line that specifically bound to the POU and βFTZ-F1 CREs, respectively. BmPOUM2 recombinant protein explicitly bound to the POU CRE. Developmental and 20E-induced expression of the BmWCP4, BmPOUM2 and BmβFTZ-F1 genes showed that BmPOUM2 and BmβFTZ-F1 were initially expressed, followed by BmWCP4. These data suggest that the 20E-induced expression of BmWCP4 is mediated by the transcription factors BmPOUM2 and BmβFTZ-F1 binding to their CREs in the regulatory sequence region of the BmWCP4 gene.

A randomized phase II study of gemcitabine (G) plus the cardiac glycoside huachansu (H) in the treatment of patients with locally advanced (LAPC) or metastatic pancreatic cancer (MPC)

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Background: Wild toad venom has been used for over 1,000 years as a traditional Chinese medicine; H, the extract of dried toad skin glands, is a potent cardiac glycoside without significant toxicity. H has demonstrated preliminary evidence of antitumor activity in phase I clinical trial evaluation (Cancer 2009, 115:5309-18).

Methods: We conducted a randomized, single-blind, phase II clinical trial of G + H versus G + placebo in patients with LAPC or MPC. Plasma bufalin levels were performed in H-treated subjects. 80 evaluable subjects accrued from October 2007 to May 2010 and were treated with G 1,000mg/m2 (iv on days 1, 8, 15, q 28d) plus either H (20 mL/m2 iv daily for 21 days followed by 7 days off, q 28d) or placebo. Demographic data is demonstrated in the table below.

Results: Grade 3/4 adverse events, objective radiographic response rates (ORR), time to progression (TTP), quality of life (QOL), and overall survival (OS) were similar in the two groups (Table). There was not a statistically significant difference in the average plasma bufalin levels in patients with a radiographic partial response (PR) or stable disease versus those with progressive disease (PD) (0.098 ± 0.093 ng/mL vs. 0.071 ± 0.048 ng/mL, p=0.679).

Conclusions: H when added to G was well tolerated but did not improve OS, TTP, QOL, or ORR. Further investigation of a more potent oral formulation of H is planned. H provided by Shenzhen 999 Traditional Chinese Medicine & Development Co., Ltd. Supported by NIH U19CA121503-01.

[Table: see text]

No significant financial relationships to disclose.

Tissue-specific dysregulation of hexose-6-phosphate dehydrogenase and glucose-6-phosphate transporter production in db/db mice as a model of type 2 diabetes

AIMS/HYPOTHESIS

Tissue-specific amplification of glucocorticoid action through 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) affects the development of the metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) mediates intracellular NADPH availability for 11β-HSD1 and depends on the glucose-6-phosphate transporter (G6PT). Little is known about the tissue-specific alterations of H6PDH and G6PT and their contributions to local glucocorticoid action in db/db mice.

METHODS

We characterised the role of H6PDH and G6PT in pre-receptor metabolism of glucocorticoids by examining the production of the hepatic 11β-HSD1-H6PDH-G6PT system in db/db mice.

RESULTS

We observed that increased production of hepatic H6PDH in db/db mice was paralleled by upregulation of hepatic G6PT production and responded to elevated circulating levels of corticosterone. Treatment of db/db mice with the glucocorticoid antagonist RU486 markedly reduced production of both H6PDH and 11β-HSD1 and improved hyperglycaemia and insulin resistance. The reduction of H6PDH and 11β-HSD1 production by RU486 was accompanied by RU486-induced suppression of hepatic G6pt (also known as Slc37a4) mRNA. Incubation of mouse primary hepatocytes with corticosterone enhanced G6PT and H6PDH production with corresponding activation of 11β-HSD1 and PEPCK: effects that were blocked by RU486. Knockdown of H6pd by small interfering RNA showed effects comparable with those of RU486 for attenuating the corticosterone-induced H6PDH production and 11ß-HSD1 reductase activity in these intact cells. Addition of the G6PT inhibitor chlorogenic acid to primary hepatocytes suppressed H6PDH production.

CONCLUSIONS/INTERPRETATION

These findings suggest that increased hepatic H6PDH and G6PT production contribute to 11β-HSD1 upregulation of local glucocorticoid action that may be related to the development of type 2 diabetes.