Promotion of fracture healing by vitamin E in rats

We investigated the effects of the antioxidant alphae-tocopherol on early- and late-phase fracture healing in a rat model. Sixty male Sprague-Dawley rats were randomized into two groups. The right tibia of each rat was fractured manually under anaesthesia, and fracture sites fixed with intramedullary Kirschner wires. The alpha-tocopherol group received 20 mg/kg alpha-tocopherol intraperitoneally; the control group received intraperitoneal saline injections. Ten rats from each group were sacrificed on day 15, day 45 and day 60. In the alpha-tocopherol group, malondialdehyde concentrations, a measure of lipid peroxidation associated with oxygen free radicals, were significantly decreased on day 15 and day 45 compared with the control group, but had regained the 15-day value on day 60. On histopathological and radiological assessment, fracture healing on day 60 was significantly more advanced in the alpha-tocopherol group. We conclude that alpha-tocopherol has a positive effect on both early and late-phase fracture healing, and may be beneficial in clinical fracture     

Estimation of C* Integral for Mismatched Welded Compact Tension Specimen

The C* integral for the compact tension (CT) specimen is calculated using the estimation equation in ASTM E1457-15. This equation was developed based on the assumption of material homogeneity and is not applicable to a welded CT specimen. In this paper, a modified equation for estimating the C* integral for a welded compact tension (CT) specimen under creep conditions is proposed. The proposed equation is defined on the basis of systematically conducted extensive finite element (FE) analyses using the ABAQUS program. A crack in the welded CT specimen is located in the center of the heat-affected zone (HAZ), because the most severe type IV cracks are located in the HAZ. The results obtained by the analysis show that the equation for estimating the C* integral in ASTM E1457-15 can underestimate the value of the C* integral for creep-soft HAZ and overestimate for creep-hard HAZ. Therefore, the proposed modified equation is suitable for describing the creep crack growth (CCG) of welded specimens.     

Arterial endothelial function in a porcine model of early stage atherosclerotic vascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States and is projected to become the leading cause of mortality in the world. Atherosclerosis is the most important single factor contributing to this disease burden. In this study, we characterize relationships between endothelial dysfunction and vascular disease in an animal model of diet-induced, early-stage atherosclerotic vascular disease. We tested the hypothesis that hypercholesterolaemia induces vascular disease and impairs endothelium-dependent relaxation (EDR) in conduit arteries of adult male Yucatan pigs. Pigs were fed a normal fat (NF) or high fat cholesterol (HFC) diet for 20-24 weeks. Results indicate that, while the HFC diet did not alter EDR in femoral or brachial arteries, EDR was significantly decreased in both carotid and coronary arteries. Sudanophilic fatty streaks were significantly present in the abdominal aorta and common carotid artery. Histopathology revealed increased intima-media thickness (IMT) and foam cell accumulation in Stary Stage I-III lesions in the abdominal aorta, common carotid artery and femoral arteries. In the coronary arteries, the accumulation of foam cells in Stary Stage I and II lesions resulted in a trend for increased IMT. There was no evidence of vascular disease in the brachial arteries. These results indicate that early stages of CVD (Stary Stage I-III) precede decreases in EDR induced by HFC diet, because femoral arteries exhibited foam cell accumulation and an increased IMT but no change in endothelial function.     

Role of insulin like growth factor-I in repair response in immature cartilage

OBJECTIVE: The purpose of this study was to investigate the effects of exogenous local Insulin like growth factor-I (IGF-I) on the repair of full-thickness articular cartilage defects in immature rabbits. DESIGN: Thirty-six skeletally immature New Zealand rabbits between 6 and 8 weeks old were used. A single defect, 3.5-mm-wide by 4-mm-deep full-thickness articular cartilage defect in the medial femoral condyle, was created. The defect was either filled with a collagen sponge or with a collagen sponge impregnated with 5 mug of recombinant IGF-I. The animals were sacrificed at 4, 8 or 12 weeks, and the repair tissue was examined macroscopically and histologically. Repair tissue was also examined immunohistochemically for the presence of type-I collagen, type-II collagen and PCNA at all weeks. RESULTS: Newly formed tissue in all of the defects in the IGF-I group had the gross, histological and histochemical appearance of a smooth, intact hyaline articular cartilage. The average total scores on the histological grading scale were significantly better (p<0.05) for the defects treated with recombinant IGF-I at all time points. Immunostaining with an antibody against type-II collagen showed the diffuse presence of the repair cartilage in the IGF-I treated defects. The control groups demonstrated minimum staining with type-II collagen antibody. CONCLUSIONS: These findings suggest that repair of full-thickness immature cartilage defects can be enhanced by recombinant IGF-I.     

Emergence of rifampicin resistance in methicillin-resistant Staphylococcus aureus isolated at a Turkish university hospital

Twenty-three rifampicin-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolated in three wards at a university hospital in Turkey between June, 2000, and February, 2001, were studied for their genetic relatedness using a combination of antibiogram, coagulase serotyping, coagulase gene polymorphism (coa-RFLP), and pulsed-field gel electrophoresis (PFGE). They all expressed high-level rifampicin resistance (MIC, >256 mg/L) and were resistant to gentamicin, kanamycin, amikacin, ciprofloxacin, tetracycline, and cadmium acetate and were susceptible to fusidic acid, vancomycin, trimethoprim, and mupirocin. They belonged to the same coagulase serotype (serotype IV) and had identical coa-RFLP patterns. In contrast, PFGE generated nine banding patterns designated type A, types A1-A5, B, C, and D. The most common PFGE pattern (type A) and its subtypes (types A1-A5) were seen in 20 (87%) of the 23 isolates in the three wards. The results demonstrated the acquisition of rifampicin resistance by different MRSA clones and the spread of one clone among patients in the three wards.     

Human and mouse perforin are processed in part through cleavage by the lysosomal cysteine proteinase cathepsin L

Summary Infection of mice with the gastrointestinal nematode Trichuris muris represents a valuable tool to investigate and dissect intestinal immune responses. Resistant mouse strains respond to T. muris infection by mounting a T helper type 2 response. Previous results have shown that CD4⁺ T cells play a critical role in protective immunity, and that CD4⁺ T cells localize to the infected large intestinal mucosa to confer protection. Further, transfer of CD4⁺ T cells from immune mice to immunodeficient SCID mice can prevent the development of a chronic infection. In the current study, we characterize the protective CD4⁺ T cells, describe their chemokine receptor expression and explore the functional significance of these receptors in recruitment to the large intestinal mucosa post‐T. muris infection. We show that the ability to mediate expulsion resides within a subpopulation of CD4⁺ T cells marked by down‐regulation of CD62L. These cells can be isolated from intestine‐draining mesenteric lymph nodes (MLN) from day 14 post‐infection, but are rare or absent in MLN before this and in spleen at all times post‐infection. Among CD4⁺ CD62L^low MLN cells, the two most abundantly expressed chemokine receptors were CCR6 and CXCR3. We demonstrate for the first time that CD4⁺ CD62L^low T‐cell migration to the large intestinal mucosa is dependent on the family of Gα_i‐coupled receptors, to which chemokine receptors belong. CCR6 and CXCR3 were however dispensable for this process because neutralization of CCR6 and CXCR3 did not prevent CD4⁺ CD62L^low cell migration to the large intestinal mucosa during T. muris infection.     

Tamoxifen enhances therapeutic effects of gemcitabine on cholangiocarcinoma tumorigenesis

Cholangiocarcinoma is a highly malignant tumor with limited therapeutic options. We have previously reported that tamoxifen (TMX) induces apoptosis of cholangiocarcinoma cells and reduces cholangiocarcinoma tumorigenesis in mice. In the present studies, we determined the effect of combination therapy of TMX and gemcitabine (GMT), another chemotherapeutical reagent for many cancers, on cholangiocarcinoma tumorigenesis and investigated the responsible mechanisms. GMT inhibited cell growth and induced apoptosis of cholangiocarcinoma cells in a concentration-dependent manner. TMX enhanced GMT-induced apoptosis of cholangiocarcinoma cells. Consistently, GMT (15?mg/kg) inhibited cholangiocarcinoma tumorigenesis in nude mice by 50%. TMX (15?mg/kg) enhanced the inhibitory effect of GMT on tumorigenesis by 33%. The inhibition of tumor growth correlated with enhanced apoptosis in tumor tissues. To elucidate the mechanisms underlying the additive effects of TMX on GMT-induced apoptosis, we determined the activation of caspases in cholangiocarcinoma cells exposed to GMT, TMX, or both. Activation of caspases 9 and 3, as well as cytochrome c release to the cytosol, was demonstrated in cells exposed to both reagents. In contrast, TMX activated caspase 2, whereas GMT had no effect. Inhibition of caspase 2 activation decreased TMX-, but not GMT-, induced activation of caspase 3 and apoptosis of cholangiocarcinoma cells. Similarly, activation of caspase 2 was found in tumors from TMX-treated mice, but not GMT-treated mice. Therefore, the enhanced effect of TMX on GMT-induced cholangiocarcinoma cell death is partially mediated by activation of caspase 2. TMX and GMT both induce apoptosis and inhibit cholangiocarcinoma tumorigenesis, which may be attributed to the activation of distinct apoptosis signals by TMX and GMT. Our studies provide in vivo evidence and molecular insight to support the use of TMX and GMT in combination as an effective therapy for cholangiocarcinoma.     

Effect of vitamin D deficiency on the 75 g oral glucose tolerance test screening and insulin resistance

Abstract

Gestational diabetes mellitus (GDM), is the most common medical complications of pregnancy. This study aimed to clarify the effect of second-trimester vitamin D deficiency on the 75?g oral glucose tolerance test (OGTT) screening and insulin resistance. A total of 120 pregnant women with a singleton pregnancy at a gestational age of 26–28?weeks were analyzed. Participants were divided into two groups according to 25-hydroxyvitamin D levels; vitamin D deficiency, and control groups. For GDM scan, 75?g OGTT was preferred. GDM prevalence was 17.5% in vitamin D deficiency group and 13.75% in control group, there is no significant difference in GDM prevalence (p?=?0.149). Fasting plasma glucose and 1-h plasma glucose levels were significantly higher in the vitamin D deficiency group than in the control group (p?<?.001 and p?<?.001, respectively). No significant differences were observed between 2-hour plasma glucose levels (p?=?.266). The HOMA-IR level was significantly higher in the vitamin D deficiency group than in the control group (p?<?.001). The findings of the present study suggested that vitamin D deficiency in the second trimester was inversely correlated with fasting and 1-h plasma glucose after 75?g glucose challenge test; also, low 25 OHD₃ levels were associated with insulin resistance.     

Multiple pathways to tumor immunity and concomitant autoimmunity

Summary: The immune repertoire contains T cells and B cells that can recognize autologous cancer cells. This repertoire is directed against self, and in some cases altered self (mutations). Priming immune responses against self antigens can be difficult. Strategies are presented using altered self to elicit immunity against self in poorly immunogenic tumor models. Mechanisms underlying immunity to self antigens on cancer cells show that the immune system can use diverse strategies for cancer immunity, in both the immunization and the effector phases. CD4⁺ T cells are typically, but not always, required for immunization. The effector phase of tumor immunity can involve cytotoxic T cells, macrophages with activating Fc receptors, and/or killer domain molecules. This diversity in the effector phase is observed even when immunizing with conserved paralogs. A consequence of tumor immunity is potentially autoimmunity, which may be undesirable. Autoimmunity uses similar mechanisms as tumor immunity, but tumor immunity and autoimmunity can uncouple. These studies open up strategies for active immunization against cancer.