Differential effect of imipenem treatment on wild-type and NK cell-deficient CD8 knockout mice during acute intra-abdominal injury

CD8 knockout mice depleted of natural killer (NK) cells by treatment with anti-asialoGM1 (CD8KO/alphaAsGM1 mice) are resistant to injury caused by cecal ligation and puncture (CLP). However, CLP-induced injury is complex. Potential sources of injury include bacterial dissemination, cecal ischemia, and translocation of bacterial toxins. We treated wild-type and CD8KO/alphaAsGM1 mice with imipenem after CLP to decrease bacterial dissemination. Additional mice were subjected to cecal ligation without puncture of the cecal wall or cecal ligation and removal of cecal contents. Imipenem treatment decreased bacterial counts by at least two orders of magnitude. However, all wild-type mice, whether treated with saline or imipenem, died by 42 h after CLP and exhibited significant hypothermia, metabolic acidosis, and high plasma cytokine concentrations. Wild-type mice subjected to cecal ligation without puncture also died, despite very low bacterial counts in blood, but wild-type mice subjected to cecal ligation and washout of cecal contents survived. In CD8KO/alphaAsGM1 mice subjected to CLP, imipenem treatment increased survival from 50% to 100%. After cecal ligation without puncture, long-term survival was 80-90% in CD8KO/alphaAsGM1 mice. Hypothermia, metabolic acidosis, and cytokine production were attenuated in CD8KO/alphaAsGM1 mice compared with wild-type controls. These results indicate that bacterial dissemination is not a major source of injury in wild-type mice after CLP, but the presence of gut flora in the cecal lumen is required for induction of systemic inflammation after cecal injury. CD8KO/alphaAsGM1 mice are resistant to the systemic manifestations of cecal injury.     

Niacin-bound chromium enhances myocardial protection from ischemia-reperfusion injury

A novel niacin-bound, chromium-based energy formula (EF; InterHealth Nutraceuticals, Benicia, CA) has been developed in conjunction with D-ribose, caffeine, ashwagandha extract (containing 5% withanolides), and selected amino acids. We have assessed the efficacy of oral administration of EF (40 mg x kg body wt(-1) x day(-1)) in male and female rats over a period of 90 consecutive days on the cardiovascular and pathophysiological functions in an isolated rat heart model. After 30, 60, and 90 days of treatment with EF, the hearts of male and female rats were subjected to 30 min of global ischemia followed by 2 h of reperfusion and were measured for myocardial ATP, creatine phosphate (CP), phosphorylated AMP kinase (p-AMPK), and heat shock proteins. Myocardial ATP and CP levels were increased in both male and female rats after EF treatment compared with the controls. Western blot analyses were performed to quantify the expression of stress-related proteins such as heat shock proteins (HSP-70, -32, and -25) and are found to be increased in both male and female rats after EF treatment. The p-AMPK level, which is a sensor for the energy state in various cell types, was also found to be increased after treatment with EF in both male and female rats. Aortic flow, maximum first derivative of developed pressure, left ventricular developed pressure, and infarct size were observed after ischemia-reperfusion and found to be significantly improved in EF-treated rats compared with control animals. Thus EF demonstrated long-term safety as well as exhibiting significant cardioprotective ability during ischemia and reperfusion injury by increased energy production, improved cardiac function, and reduced infarct size.     

Threads that Guide or Ties that Bind: William Kirby and the Essentialism Story

Nineteenth-century British entomologist William Kirby is best known for his generic division of bees based on tongues and his vigorous defence of natural theology. Focusing on these aspects of Kirby’s work has lead many current scholars to characterise Kirby as an “essentialist.” As a result of this characterisation, many important aspects of his work, Monographia Apum Angliæ (1802) have been over-looked or misunderstood. Kirby’s religious devotion, for example, have lead some scholars to assume Kirby used the term “type” for connecting an ontological assumption about essences with a creationist assumption about species fixity, which I argue conceals a variety of ways Kirby employed the term. Also, Kirby frequently cautioned against organising a classification system exclusively by what he called “analytic reasoning,” a style of reasoning 20th century scholars often associate with Aristotelian logic of division. I argue that Kirby’s critique of analytic reasoning brought the virtues of his own methodological agenda into sharp relief. Kirby used familiar metaphors in the natural history literature – Ariadne’s thread, the Eleusinian mysteries, and Bacon’s bee and spider metaphors – to emphasise the virtues of building tradition and cooperation in the goals and methodological practices of 19th century British naturalists.     

Niacin bound chromium treatment induces myocardial Glut-4 translocation and caveolar interaction via Akt,AMPK and eNOS phosphorylation in streptozotocin induced diabetic rats after ischemia-reperfusion injury

Diabetes, one of the major risk factors of metabolic syndrome culminates in the development of Ischemic Heart Disease (IHD). Refined diets that lack micronutrients, mainly trivalent chromium (Cr³⁺) have been identified as the contributor in the rising incidence of diabetes. We investigated the effect of niacin-bound chromium (NBC) during ischemia/reperfusion (IR) injury in streptozotocin induced diabetic rats. Rats were randomized into: Control (Con); Diabetic (Dia) and Diabetic rats fed with NBC (Dia + NBC). After 30 days of treatment, the isolated hearts were subjected to 30 min of global ischemia followed by 2 h of reperfusion. NBC treatment demonstrated significant increase in left ventricular functions and significant reduction in infarct size and cardiomyocyte apoptosis in Dia + NBC compared with Dia. Increased Glut-4 translocation to the lipid raft fractions was also observed in Dia + NBC compared to Dia. Reduced Cav-1 and increased Cav-3 expression along with phosphorylation of Akt, eNOS and AMPK might have resulted in increased Glut-4 translocation in Dia + NBC. Our results indicate that the cardioprotective effect of NBC is mediated by increased activation of AMPK, Akt and eNOS resulting in increased translocation of Glut-4 to the caveolar raft fractions thereby alleviating the effects of IR injury in the diabetic myocardium.     

Social Stigma and Knowledge of Tuberculosis and HIV among Patients with Both Diseases in Thailand

Introduction

Disease-related stigma and knowledge are believed to be associated with patients'' willingness to seek treatment and adherence to treatment. HIV-associated tuberculosis (TB) presents unique challenges, because TB and HIV are both medically complex and stigmatizing diseases. In Thailand, we assessed knowledge and beliefs about these diseases among HIV-infected TB patients.

Methods

We prospectively interviewed and examined HIV-infected TB patients from three provinces and one national referral hospital in Thailand from 2005–2006. At the beginning of TB treatment, we asked patients standardized questions about TB stigma, TB knowledge, and HIV knowledge. Responses were grouped into scores; scores equal to or greater than the median score of study population were considered high. Multiple logistic regression analysis was used to identify factors associated with scores.

Results

Of 769 patients enrolled, 500 (65%) reported high TB stigma, 177 (23%) low TB knowledge, and 379 (49%) low HIV knowledge. Patients reporting high TB stigma were more likely to have taken antibiotics before TB treatment, to have first visited a traditional healer or private provider, to not know that monogamy can reduce the risk of acquiring HIV infection, and to have been hospitalized at enrollment. Patients with low TB knowledge were more likely to have severe TB disease, to be hospitalized at enrollment, to be treated at the national infectious diseases referral hospital, and to have low HIV knowledge. Patients with low HIV knowledge were more likely to know a TB patient and to have low TB knowledge.

Discussion

We found that stigma and low disease-specific knowledge were common among HIV-infected TB patients and associated with similar factors. Further research is needed to determine whether reducing stigma and increasing TB and HIV knowledge among the general community and patients reduces diagnostic delay and improves patient outcomes.     

A novel 9-bp insertion detected in steroid 21-hydroxylase gene (CYP21A2): prediction of its structural and functional implications by computational methods

Background

Steroid 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia (CAH). Detection of underlying mutations in CYP21A2 gene encoding steroid 21-hydroxylase enzyme is helpful both for confirmation of diagnosis and management of CAH patients. Here we report a novel 9-bp insertion in CYP21A2 gene and its structural and functional consequences on P450c21 protein by molecular modeling and molecular dynamics simulations methods.

Methods

A 30-day-old child was referred to our laboratory for molecular diagnosis of CAH. Sequencing of the entire CYP21A2 gene revealed a novel insertion (duplication) of 9-bp in exon 2 of one allele and a well-known mutation I172N in exon 4 of other allele. Molecular modeling and simulation studies were carried out to understand the plausible structural and functional implications caused by the novel mutation.

Results

Insertion of the nine bases in exon 2 resulted in addition of three valine residues at codon 71 of the P450c21 protein. Molecular dynamics simulations revealed that the mutant exhibits a faster unfolding kinetics and an overall destabilization of the structure due to the triple valine insertion was also observed.

Conclusion

The novel 9-bp insertion in exon 2 of CYP21A2 genesignificantly lowers the structural stability of P450c21 thereby leading to the probable loss of its function.     

Biodegradable dental implants of ciprofloxacin beta-cyclodextrin inclusion complex in the treatment of periodontitis

Dental implants of ciprofloxacin beta-cyclodextrin inclusion complex were formulated using poly (epsilon-caprolactone), a biodegradable polymer and evaluated. Clinical evaluation was carried out in ten patients with acute peridontitis. Various clinical parameters, viz. gingival index, plaque score, attachment gain, reduction in pocket depth were evaluated at 10, 20, 30, 40 days of treatment and compared with placebo as control. A significant (P < 0.0001) improvement in the healing of periodontal pockets treated with ciprofloxacin beta-cyclodextrin implant was observed in most of the clinical parameters. Estimation of gingival crevicular fluids (GCF) for the drug content revealed that drug levels above the minimum inhibitory concentration (10.2 micrograms/mg) for many of the periodontal pathogens were maintained throughout the period of study (40 days). This confirms the clinical efficacy of the dose and the duration of the study. It was found that biodegradable carrier was better accepted than the non-biodegradable carriers reported earlier.