Therapeutic Effects of Procainamide on Endotoxin-Induced Rhabdomyolysis in Rats

Overt systemic inflammatory response is a predisposing mechanism for infection-induced skeletal muscle damage and rhabdomyolysis. Aberrant DNA methylation plays a crucial role in the pathophysiology of excessive inflammatory response. The antiarrhythmic drug procainamide is a non-nucleoside inhibitor of DNA methyltransferase 1 (DNMT1) used to alleviate DNA hypermethylation. Therefore, we evaluated the effects of procainamide on the syndromes and complications of rhabdomyolysis rats induced by lipopolysaccharide (LPS). Rhabdomyolysis animal model was established by intravenous infusion of LPS (5 mg/kg) accompanied by procainamide therapy (50 mg/kg). During the experimental period, the changes of hemodynamics, muscle injury index, kidney function, blood gas, blood electrolytes, blood glucose, and plasma interleukin-6 (IL-6) levels were examined. Kidneys and lungs were exercised to analyze superoxide production, neutrophil infiltration, and DNMTs expression. The rats in this model showed similar clinical syndromes and complications of rhabdomyolysis including high levels of plasma creatine kinase, acute kidney injury, hyperkalemia, hypocalcemia, metabolic acidosis, hypotension, tachycardia, and hypoglycemia. The increases of lung DNMT1 expression and plasma IL-6 concentration were also observed in rhabdomyolysis animals induced by LPS. Treatment with procainamide not only inhibited the overexpression of DNMT1 but also diminished the overproduction of IL-6 in rhabdomyolysis rats. In addition, procainamide improved muscle damage, renal dysfunction, electrolytes disturbance, metabolic acidosis, hypotension, and hypoglycemia in the rats with rhabdomyolysis. Moreover, another DNMT inhibitor hydralazine mitigated hypoglycemia, muscle damage, and renal dysfunction in rhabdomyolysis rats. These findings reveal that therapeutic effects of procainamide could be based on the suppression of DNMT1 and pro-inflammatory cytokine in endotoxin-induced rhabdomyolysis.     

Inducible activation of IFI 16 results in suppression of telomerase activity,growth suppression and induction of cellular senescence

Expression of the human HIN‐200 family member IFI 16 has been reported to suppress cell growth and contribute to the onset of cellular senescence. However the molecular events involved in this process have not been fully characterised. We fused IFI 16 to the estrogen receptor ligand‐binding domain to establish an inducible model for studying the molecular events that cause these phenomena. In cells induced to express the ER‐IFI 16 within the nucleus there was a decrease in cellular proliferation and concomitant growth arrest in the G1 phase of the cell cycle. Unlike previous reports, this did not appear to involve the p53‐p21^WAF1/CIP1‐cdk2‐pRb pathway. Following nuclear expression of ER‐IFI 16 we noted senescence‐like morphological changes and expression of senescence‐associated β‐galactosidase in growth arrested cells. Importantly, we also found a marked reduction in telomerase activity in arrested cells compared to controls. Moreover, IFI 16 and hTERT co‐localised within the nucleus and these two proteins physically interacted in vivo and in vitro. Together, these data suggest that IFI 16 may act as an endogenous regulator of telomerase activity and, through its interaction with hTERT, contributes to the inhibition of proliferation and induces a senescence‐like state. J. Cell. Biochem. 109: 103–112, 2010. © 2009 Wiley‐Liss, Inc.     

Comparison of the egg recovery rates and limit of detection for soil-transmitted helminths using the Kato-Katz thick smear,faecal flotation and quantitative real-time PCR in human stool

BackgroundMonitoring the success of soil-transmitted helminth (STH) control programs relies on accurate diagnosis and quantitative assessment of infection prevalence and intensity. As preventative chemotherapeutic program coverage for STH expands, the necessity of gaining insights into the relative or comparative sensitivities, in terms of limits of detection (LOD) and egg-recovery-rates (ERR) for microscopy and quantitative polymerase chain reaction qPCR-based diagnostic techniques becomes imperative to inform suitability for their intended use for large scale STH monitoring and treatment efficacy studies.Methodology/Principal findingsThe diagnostic performance in terms of ERR and LOD of the Kato-Katz (KK) thick smear technique, sodium nitrate (NaNO₃) faecal floatation (FF) and qPCR for the accurate detection and enumeration of STH eggs were calculated and expressed in eggs per gram (EPG), by experimentally seeding parasite-free human faeces with Ascaris spp., Trichuris spp. and Necator americanus eggs representing low, medium and high intensity infections. The efficiency of NaNO₃ flotation was also calculated over a range of specific gravities (SpGr) for the optimum recovery of STH eggs. FF of SpGr 1.30 recovered 62.7%, 11% and 8.7% more Trichuris spp., Necator americanus and Ascaris spp. eggs respectively, than the recommended SpGr of 1.20. All diagnostic methods demonstrated strong direct correlation to the intensity of seeded EPG. KK and FF (SpGr 1.30) resulted in significant lower ERRs compared to qPCR (p <0.05). qPCR demonstrated significantly (p <0.05) greater sensitivity with an ability to detect as little as 5 EPG for all three STH, compared to 50 EPG by KK and FF (SpGr 1.30).Conclusions/SignificanceThis study compares the diagnostic parameters in terms of LOD and ERRs of STHs for the KK, FF and qPCR. These results indicate that the diagnostic performance of qPCR assays should be considered by control programs in the phase that aims to seek confirmation of transmission break and cessation of preventive chemotherapy in low-transmission settings, in line with the control targets of the WHO neglected tropical diseases 2030 Roadmap.     

Leukocyte numbers and function in subjects eating <Emphasis Type="Italic">n</Emphasis>-3 enriched foods: selective depression of natural killer cell levels

Introduction  

While consumption of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) has been recommended for those at risk of inflammatory disease such as rheumatoid arthritis, the mechanism of their anti-inflammatory effect remains to be clearly defined, particularly in relation to the dose and type of n-3 LCPUFA. The objective of this study was to determine whether varying the levels of n-3 LCPUFA in erythrocyte membrane lipids, following dietary supplementation, is associated with altered numbers and function of circulating leukocytes conducive to protection against inflammation.     

Insecticide susceptibility status of Aedes aegypti (Diptera: Culicidae) from Townsville

Insecticide susceptibility of a 1995 Townsville Aedes aegypti (L.) population was investigated in the laboratory according to World Health Organization guidelines. Using baseline data from two Townsville populations (1955 and 1989), larval bioassays detected significant increases in susceptibility to synthetic pyrethroids and malathion, and significant reductions in susceptibility to most organophosphates and propoxur. Adult bioassays detected significant resistance to bendiocarb and DDT. Comparison of larval data with the international reference ROCK strain showed substantial resistance to have developed to malathion and fenthion. Further analysis revealed the presence of distinct substrains in the baseline 1989 population, which displayed varying levels of temephos susceptibility. We concluded that susceptibility investigations should assess mosquito populations collected from many sites within an area rather than taking a single population from one site, and that the 1989 Ae. aegypti colony would be unsuitable for use as a susceptible reference population.     

Induction of acyl coenzyme A synthetase and hydroxyacyl coenzyme A dehydrogenase during fatty acid degradation in Neurospora crassa

Neurospora crassa is able to use long-chain fatty acids as the sole carbon and energy source. After growth on oleate there was nearly a 10-fold induction of the acyl coenzyme A (CoA) synthetase and a fivefold increase in the activity of the 3-hydroxyacyl-CoA dehydrogenase. There was a slight induction of the enoyl-CoA hydratase and 3-ketoacyl-CoA thiolase, but no apparent induction of the flavin-linked acyl-CoA dehydrogenase. These noncoordinate changes in the fatty acid degradation enzymes suggest that they are not organized into a multienzyme complex as is found in bacteria.