Role of lysine in the replication of reovirus

Summary Omission of lysine from the extracellular medium of HeLa cells infected with reovirus type 2 results in the production of virus structures which could be separated by isopycnic sedimentation in CsCl into a top band of empty particles (L-T) and a bottom band (L-B) containing a mixture of defective and complete virus structures. The L-T and L-B particles were found to be similar to the complete virus in the following properties: adsorption characteristics to HeLa cells, RNA base composition, and qualitative distribution of the double-stranded viral RNA segments and structural viral proteins.Polyacrylamide gel electrophoresis analyses of the capsid proteins of L-T and L-B particles indicated a quantitative alteration in the distribution of their protein components. In addition, L-T particles contained markedly reduced amounts of the single-stranded adenine-rich RNA component. The synthesis of viral double-stranded RNA and cytoplasmic proteins were both reduced in lysine-deficient cell cultures. In contrast, the synthesis of single-stranded RNA remained unaltered. Addition of increasing concentrations of lysine to lysine-deficient cultures resulted in increasing yields of infectious virus.This investigation was supported by research grant AI 07647 from the National Institutes of Health, U.S. Public Health Service.Post-doctoral trainee NIH 5 T 1 AI 243.     

Elephantiasis nostras verrucosa: beneficial effect of oral etretinate therapy

Elephantiasis nostras verrucosa is characterized by chronic secondary, non-filarial lymphoedema due to recurrent lymphangitis, dermal fibrosis, and epidermal changes consisting of hyperkeratotic, verrucous and papillomatous lesions. Histologically, there is pseudoepitheliomatous hyperplasia. Therapeutic efforts should aim to reduce lymph stasis, which will also lead to improvement of the cutaneous changes. In this study, rapid disappearance of the hyperkeratotic and verrucous lesions, remarkable flattening of the papillomatous nodules and improvement of lymphoedema occurred in three obese patients treated with etretinate in an initial dose of 0.6-0.75 mg/kg/day for 4-6 weeks. Monitoring of plasma concentrations of etretinate, acitretin and 13-cis-acitretin by HPLC revealed sufficient short-time absorption (4 h) and bioavailability of the drug (30 days; two out of three patients). Long-term maintenance therapy in one patient produced a remarkable improvement in the lymphoedema; another patient relapsed after discontinuation of the etretinate and responded again after this was reintroduced. In the third patient treatment was withdrawn because of an increase in triglycerides, but improvement persisted 6 months later. The clinical side-effects of oral retinoid therapy were moderate and well tolerated.     

Grafting antibiofilm polymer hydrogel film onto catheter by SARA SI-ATRP

Abstract

Catheters are widely used and play an important role in medicine. However, catheter-associated infection is prevalent even under stringent sterile conditions. Biofilms are formed when bacteria populate the surfaces of catheters. This makes the biofilm resistant to antibiotics. Hence, it is imperative for there to be an inherently antifouling and anti-bacterial catheter to mitigate the formation of biofilm. This paper aims to outline the synthesis of non-leachable anti-biofilm and anti-bacterial cationic film coatings through direct polymerization using supplemental activator and reducing agent surface initiated atom transfer radical polymerization (SARA SI-ATRP). Three crosslinked cationic coatings comprising of Diallyl dimethyl ammonium chloride (DADMAC), or ε-poly-L-lysine HCl methacrylic acid (EPL-MA) together with a crosslinker (polyethylene glycol dimethacrylate, PEGDMA) were investigated. These non-leachable covalently linked coatings with DADMAC can achieve more than 2 log reduction (99.0%) with Methicillin-resistant Staphylococcus aureus (MRSA) and 1.25 log reduction (94.4%) with Vancomycin resistant Enterococcus (VRE) in in vitro studies.