Growth and structure of crystalline silica sheet on Ru(0001)

Thin SiO₂ films were grown on a Ru(0001) single crystal and studied by photoelectron spectroscopy, infrared spectroscopy and scanning probe microscopy. The experimental results in combination with density functional theory calculations provide compelling evidence for the formation of crystalline, double-layer sheet silica weakly bound to a metal substrate.

The beneficial effect of n-3 polyunsaturated fatty acids on doxorubicin-induced chronic heart failure in rats

This study was designed to assess the effects of dietary supplementation with n-3 polyunsaturated fatty acids (PUFA) from fish oil on the response of doxorubicin-induced chronic heart failure in rats. Male Sprague-Dawley rats were treated daily for 8 weeks with normal saline or n-3 PUFA intragastrically after induction of myocardial injury by intraperitoneal injection of doxorubicin 2 mg/kg once weekly for 8 weeks. Cardiac function was assessed by echocardiography. The cytoprotective role of n-3 PUFA against doxorubicin-induced myocardial injury was demonstrated by light microscopy, and serum cytokines (tumour necrosis factor-alpha and interleukin-10) were analysed by enzyme-linked immunosorbent assay. Doxorubicin induced death, alterations in echocardiography parameters and histological damage, all of which are features that characterize heart failure. There were significant differences between the doxorubicin-induced heart failure group and the n-3 PUFA-treated group in terms of echocardiography parameters and cytokine changes. Thus, dietary supplementation with n-3 PUFA attenuated doxorubicin-induced cardiac dysfunction, an effect that might be associated with recovery from an imbalance of the cytokine network.

Celastrol attenuates hypertension-induced inflammation and oxidative stress in vascular smooth muscle cells via induction of heme oxygenase-1

BACKGROUND

The aim of this study was to investigate the potential beneficial effects of celastrol, a compound with anti-inflammatory and antioxidant properties, on vascular smooth muscle cells (VSMCs) under hypertensive conditions.

METHODS

Hypertension was induced in rats by fructose feeding. Hypertensive rats were injected with celastrol, and systolic blood pressure (SBP) and diastolic BP (DBP) were monitored by the tail-cuff method. Insulin sensitivity in animals was measured by glucose tolerance test (GTT). Serum levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay. Real-time reverse transcription-PCR and western blot were applied to quantify mRNA and protein levels in tissues and primary cultured VSMCs. Generation of reactive oxygen species (ROS) was measured using lucigenin chemiluminescence for tissue homogenates and dichlorodihydrofluorescein diacetate staining for VSMC cells.

RESULTS

Celastrol decreased both SBP and DBP while improving insulin sensitivity in fructose-induced hypertensive rats. Celastrol also inhibited vascular and cardiac hypertrophy. Hypertension augmented circulating and mRNA levels of inflammatory cytokines, and celastrol treatment suppressed their induction. Celastrol also blocked activation of extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) and Akt signaling both in vivo and in vitro. More importantly, celastrol increased heme oxygenase-1 (HO-1) expression and activity, whereas zinc protoporphyrin 9 (ZnPP9), a HO-1 inhibitor, partially abolished the beneficial effects of celastrol on hypertensive rats and VSMCs. Finally, ROS generation in tissue homogenates and in VSMCs was reduced by celastrol.

CONCLUSIONS

These findings suggest that celastrol attenuates hypertension-induced inflammation and oxidative stress in VSMCs via HO-1 induction, and this compound may therefore serve as a novel drug to treat hypertension.

Preparation, characterization and in vitro analysis of novel structured nanofibrous scaffolds for bone tissue engineering

In a previous study, a three-dimensional nanofibrous spiral scaffold for bone tissue engineering was developed, which showed enhanced human osteoblast cell attachment, proliferation and differentiation compared with traditional cylinder scaffolds, owing to the incorporation of spiral structures and nanofiber. However, the application of these scaffolds to bone tissue engineering was limited by their weak mechanical strength. This limitation triggered the design for novel structured scaffolds with reinforced physical characteristics. In this study, spiral polycaprolactone (PCL) nanofibrous scaffolds were inserted into poly(lactide-co-glycolide) (PLGA) microsphere sintered tubular scaffolds to form integrated scaffolds to provide mechanical properties and bioactivity appropriate for bone tissue engineering. Four experiment groups were designed: PLGA cylinder scaffold; PLGA tubular scaffold; PLGA tubular scaffold with PCL spiral structured inner core; PLGA tubular scaffold with PCL nanofiber containing spiral structured inner core. The morphology, porosity and mechanical properties of the scaffolds were characterized. Furthermore, human osteoblastic cells were seeded on these scaffolds, and the cell attachment, proliferation, differentiation and mineralized matrix deposition on the scaffolds were evaluated. The integrated scaffolds had Young's modulus 250-300 MPa, and compressive strength 8-11 MPa under uniaxial compression. With the addition of an inner highly porous insert to the tubular shell, human osteoblast cells seeded on the integrated scaffolds showed slightly higher cell proliferation, 20-25% more alkaline phosphatase expression and twofold higher calcium deposition than those on the cylinder and tubular scaffolds. Furthermore, compared with sintered PLGA cylinder scaffolds, the integrated scaffolds allowed better cellular infiltration Therefore, this design demonstrates great potential for integrated scaffolds in bone tissue engineering applications.

Impaired dopaminergic neurotransmission and microtubule-associated protein tau alterations in human LRRK2 transgenic mice

Mutations in the Leucine Rich Repeat Kinase 2 (LRRK2) gene, first described in 2004 have now emerged as the most important genetic finding in both autosomal dominant and sporadic Parkinson's disease (PD). While a formidable research effort has ensued since the initial gene discovery, little is known of either the normal or the pathological role of LRRK2. We have created lines of mice that express human wild-type (hWT) or G2019S Lrrk2 via bacterial artificial chromosome (BAC) transgenesis. In vivo analysis of the dopaminergic system revealed abnormal dopamine neurotransmission in both hWT and G2019S transgenic mice evidenced by a decrease in extra-cellular dopamine levels, which was detected without pharmacological manipulation. Immunopathological analysis revealed changes in localization and increased phosphorylation of microtubule binding protein tau in G2019S mice. Quantitative biochemical analysis confirmed the presence of differential phospho-tau species in G2019S mice but surprisingly, upon dephosphorylation the tau isoform banding pattern in G2019S mice remained altered. This suggests that other post-translational modifications of tau occur in G2019S mice. We hypothesize that Lrrk2 may impact on tau processing which subsequently leads to increased phosphorylation. Our models will be useful for further understanding of the mechanistic actions of LRRK2 and future therapeutic screening.

Telmisartan alleviates rosiglitazone-induced bone loss in ovariectomized spontaneous hypertensive rats

In the present study, we systematically examined telmisartan, an angiotensin AT(1) receptor antagonist, on rosiglitazone-induced bone loss in ovariectomized spontaneously hypertensive rats. Telmisartan (5 mg/kg/d, 90 days) was found to be able to significantly alleviate rosiglitazone (10 mg/kg/d, 90 days)-induced decrease in BMD of femur and lumbar vertebrae. The BMD changes were associated with positive biomechanical changes of lumbar vertebrae, improvements in microarchitecture of tibial metaphysic and normalized serum osteocalcin (OC) levels and urinary deoxypyridinoline/creatinine (DPD/Cr) ratio. MicroCT analysis of the tibial metaphysis showed that telmisartan significantly prevented the decreases in bone volume/tissue volume (BV/TV), connect density (Conn. D.), trabecular number (Tb. N.) and trabecular thickness (Tb. Th.), and increase in trabecular separation (Tb. Sp.) induced by rosiglitazone. Histomorphometric analysis also showed that telmisartan had protective effects on rosiglitazone-reduced bone formation indices such as histomorphometric bone volume fraction (BV/TV-Histo), mineralizing surface/bone surface (MS/BS), mineral apposition rate (MAR) and bone formation rate (BFR/BS). Our study clearly showed that telmisartan alleviated rosiglitazone-induced bone loss in ovariectomized spontaneous hypertensive rats. The relief of bone loss provides a possible therapeutic application of telmisartan with rosiglitazone for the treatment of elderly women patients afflicted with metabolic syndrome.

Contribution of magnetic resonance imaging to prenatal differential diagnosis of renal tumors: report of two cases and review of the literature

Enlargement of a kidney on prenatal imaging is usually due to hydronephrosis or cystic renal disease, and much less often results from solid tumors such as mesoblastic nephroma, Wilms' tumor, nephroblastomatosis, renal sarcoma, and angiomyolipoma. All can be diagnosed by ultrasound. Magnetic resonance imaging is useful not only in confirming the presence of a renal mass, but also in the evaluation of the contralateral kidney for subtle abnormalities. We present one case each of Wilms' tumor and mesoblastic nephroma, both detected on antenatal ultrasound and further studied with fetal magnetic resonance imaging.

Skeletal phenotype of mice with a null mutation in Cav 1.3 L-type calcium channel

This study aimed to understand the role of Cav1.3, one of the four L-type voltage sensitive calcium channels (VSCC) alpha(1) subunits, in the skeletal response to mechanical loading and intermittent PTH treatment. The Cav1.3 mRNA is expressed in osteoblasts. The Cav1.3 mRNA level in male wild type mice is higher than those in female. Loss of Cav1.3 resulted in a smaller skeleton in male mice as indicated by significantly lower body weight, less bone mineral content and smaller cross-sectional area of femoral midshaft. However, the osteogenic response to mechanical loading of the ulna was normal in Cav1.3(-/-) compared to the normal control mice. Male mice Cav1.3(-/-) were then treated daily with PTH at a dose of 40 microg/kg. A 6-week course of intermittent PTH treatment enhanced bone mineral content and mechanical strength equally in wild type control and Cav1.3 null mice. We also found that Cav1.2 subunit significantly increases in the absence of Cav1.3 gene. In conclusion, Cav1.3 is involved in bone metabolism, especially in male mice. Cav1.3 does not mediate osteoblast response to mechanical loading and PTH. Our data suggest that Cav1.1 and Cav1.2 subunits may substitute for Cav1.3 to maintain bone response to mechanical loading.

Jak/STAT signaling is involved in the inflammatory infiltration of the kidneys in MRL/lpr mice

Cytokines are known to play an important role in the pathogenesis of lupus nephritis (LN) and the Jak/STAT (Janus kinase-signal transducer and activator of transcription factor) pathway is important in mediating signal transduction of cytokines. This study examined the pathogenic role of Jak/STAT signaling in LN. MRL/lpr mice were either treated with a selective Jak2 inhibitor tyrphostin AG490 or with vehicle alone from 12 weeks of age until being sacrificed at week 20. AG490 significantly inhibited the phosphorylation of Jak2 and STAT1 (p < 0.05). Compared with the vehicle-treated mice, AG490 treatment significantly reduced proteinuria, improved renal function and suppressed histological lesions of the kidneys and salivary glands (p < 0.05). AG490 treatment significantly inhibited the renal expression of monocyte chemotactic protein (MCP)-1, interferon (IFN)-gamma and class II MHC, which was accompanied by reduced renal infiltration of T cells and macrophages (p < 0.05). In addition, AG490 treatment resulted in a decrease in serum anti-double-stranded DNA (anti-dsDNA) antibody and attenuated the deposition of IgG and C3 in the kidneys (p < 0.05). This study demonstrated that Jak/STAT pathway is implicated in the progression of renal inflammation in MRL/lpr mice and targeting this pathway may provide a potential therapeutic approach for LN.

Comparative In Vivo Study on the Desensitizing Efficacy of Dentin Desensitizers and One-bottle Self-etching Adhesives

Dentin desensitizers and one-bottle self-etching adhesives can significantly reduce dentin hypersensitivity. Clinical desensitizing effectiveness depends on the individual dentin desensitizers/adhesives used.

MicroRNA-25 functions in regulation of pigmentation by targeting the transcription factor MITF in Alpaca (Lama pacos) skin melanocytes

Although the influence of endocrine factors is well established, the molecular and cellular mechanisms controlling coat color are not completely understood. A major mechanism for post-transcriptional regulation of gene expression is through the action of microRNAs (miRNAs), which anneal to the 3' untranslated region of mRNAs in a sequence-specific fashion and either block translation or promote transcript degradation. In this study, we investigated the expression of miRNAs in the skin of alpacas with brown vs white coat color using a microarray screen; identified potential mRNA targets for identified miRNAs among coat color genes; and subsequently determined the ability of a specific, differentially expressed miRNA (miR-25) to suppress expression of micropthalmia-associated transcription factor (MITF), a predicted miR-25 target gene that regulates genes linked to coat color. Expression of 10 different miRNA species in the skin of alpacas with brown vs white coat color was identified from microarray screens. Of the 10 alpaca skin miRNAs identified, predicted binding sites in the 3' untranslated region of RNAs encoding for known genes linked to coat color were primarily for miR-25, but sites were also identified for miR-129 and miR-377. Potential miR-25 binding sites were present in transcripts encoding for 11 coat color genes, including MITF. An inverse relationship between transcript abundance for MITF and miR-25 was observed in skin samples collected from alpacas with white vs brown coat color. Furthermore, overexpression of miR-25 in cultured melanocytes reduced MITF mRNA and protein abundance and corresponding mRNA abundance for the MITF-regulated enzymes tyrosinase and tyrosinase-related protein 1. Results support a novel functional role for miRNA-25 in the regulation of gene expression linked to coat color.

Hyperglycemia suppresses ABCA1 expression in vascular smooth muscle cells

Hyperglycemia is a major risk factor for atherosclerotic disease. The ATP-binding cassette transporter A1 (ABCA1) functions as a pivotal regulator of lipid efflux from cells to apolipoproteins and is thus involved in lowering the risk of atherosclerosis. In this study, we have examined the glucose-mediated regulation of the ABCA1 gene expression in vascular smooth muscle cells. ABCA1 expression was examined by real-time polymerase chain reaction (PCR), Western blot analysis, and reporter gene assay. The results showed that the expression of the ABCA1 mRNA and protein decreased after the cells were treated with 22.4 mM glucose for 48 h. The transcriptional activity of the ABCA1 promoter paralleled the endogenous expression of the ABCA1 gene. Next, we used inhibitors of certain signal transduction pathways to demonstrate that the glucose-induced ABCA1 suppression is sensitive to the p38-mitogen-activated protein kinase (MAPK) inhibitors. The expression of a constitutively active form of p38-MAPK in the cells inhibited the ABCA1 promoter activity, irrespective of the presence of glucose. A dominant-negative mutant of p38-MAPK abrogated the inhibitory effect of glucose on the ABCA1 promoter activity. These results indicate that the glucose-induced suppression of ABCA1 expression is partially mediated by the activation of the p38-MAPK pathway.

Early Onset of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) after Allogeneic Haematopoietic Stem Cell Transplantation: Case Report and Review of the Literature

Severe hyponatraemia and syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare but fatal complication following stem cell transplantation (SCT). This case report details a patient with early-onset SIADH after allogeneic haematopoietic SCT (allo-HSCT) and reviews the literature on risk factors for the development of this condition. The patient, who had chronic myelogenous leukaemia, developed acute graft-versus-host disease (GVHD) on day 5 after allo-HSCT, which was relieved promptly by steroids. On day 18, he presented with hyponatraemia, which was refractory. Despite intensive restriction of fluid and administration of hypertonic saline, his condition worsened and he died of multiple systemic organ dysfunction. A review of the literature reveals that early-onset SIADH following SCT is insidious, but progresses rapidly. The severity of the disorder is underestimated because of the non-specific clinical features and the lack of effective treatment. Myeloablative conditioning and acute GVHD are two major important predisposing factors in SIADH.

Effects of n-3 Polyunsaturated Fatty Acid Therapy on Plasma Inflammatory Markers and N-Terminal Pro-brain Natriuretic Peptide in Elderly Patients with Chronic Heart Failure

Several previous studies have suggested that n-3 polyunsaturated fatty acids ( n-3 PUFA) can exert favourable effects in patients with heart failure, but the mechanisms involved are not fully understood. This study was designed to investigate the effects of n-3 PUFA on circulating inflammatory markers and N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with heart failure. Seventy-six patients with heart failure were randomly assigned to receive 2 g/day of n-3 PUFA or placebo for 3 months. Treatment with n-3 PUFA significantly decreased plasma levels of tumour necrosis factor, interleukin-6, intercellular adhesion molecule 1 and NT-proBNP. Left ventricular ejection fraction showed a small, non-significant improvement. High-sensitivity C-reactive protein levels decreased significantly in smokers after n-3 PUFA treatment. Thus, n-3 PUFA can reduce levels of plasma inflammatory markers and NT-proBNP as biomarkers of risk stratification in patients with heart failure. n-3 PUFA may offer a novel therapy for heart failure.