Treatment of hepatitis C infection for current or former substance abusers in a community setting.

Substance abusers account for the largest number of hepatitis C infected cases in developed countries. We describe a care model for treating current or former substance abusers with antiviral therapy for hepatitis C virus (HCV) infection. The care model involved hepatitis nurses, a psychologist, infectious disease specialist and primary care physicians. Clients met selection criteria including regular attendance at clinic appointments and social stability. Use of alcohol and illicit substances was monitored with urine toxicology screens. The association between substance use, rates of completion of therapy and rates of response were assessed using multivariable regression analyses. A total of 109 clients (75 with genotype 1/4 and 34 with genotype 2/3) received at least one injection with pegylated interferon between November 2002 and January 2006. Treatment completion rates of 61 and 74% were achieved for genotypes 1/4 and 2/3, respectively. Treatment response rates in an intention to treat analysis were 51% for genotypes 1/4 and 68% for genotypes 2/3. A positive urine toxicology screen indicating use of illicit substances 6 months prior to initiating therapy was significantly associated with lower rates of treatment completion but not lower rates of sustained virological response. A positive urine screen indicating use of alcohol prior to therapy was significantly associated with lower rates of completion and lower rates of response. Rates of completion and response are comparable to non-substance abusing populations. Antiviral therapy for HCV infection can be successful within the context of ongoing care for substance abuse for carefully selected patients.

Two nursing home outbreaks of respiratory infection with Legionella sainthelensi.

OBJECTIVE: To describe outbreaks of infection caused by Legionella sainthelensi occurring in older residents of two nursing homes and to determine risk factors for the development of infection. DESIGN: Descriptive epidemiology and a case-control study. SETTING: Two nursing homes (140 beds and 254 beds in nursing homes A and B, respectively) located in southern Ontario, Canada, experiencing outbreaks of respiratory tract infection in July and August 1994. SUBJECTS: Case-residents of the two nursing homes who met clinical and laboratory criteria for Legionella infection. Control-residents were defined as those who were in the homes during the outbreaks and were asymptomatic. MEASUREMENTS: Active surveillance was conducted in both nursing homes to identify symptomatic residents. Residents with fever or respiratory tract symptoms had nasopharyngeal swabs taken for viral antigen detection and culture, urine for Legionella antigen detection, and acute and convalescent serology for viruses, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella. Chest X-rays were performed, and an attempt was made to obtain blood and sputum cultures. Water samples from shower heads, faucets, and air conditioning units were collected for Legionella culture and polymerase chain reaction (PCR) assay. A case-control study was done to assess possible risk factors for legionellosis. RESULTS: Twenty-nine cases -- 17 in nursing home A; 12 in nursing home B - were identified. Four (14%) case-residents had documented pneumonia and four case-residents died. Univariate analysis revealed that a history of stroke (odds ratio (OR) 2.3 (95% CI, 1.0-5.3)), eating pureed food (OR 4.6 (95% CI, 1.6-12.7)), and having fluids administered with medication (OR 2.5 (95% CI, 1.0-5.9)) were significant risk factors. Cases were less likely to wear dentures (OR .4 (95% CI, .2-.9)) or to eat solid food (OR .3, (95% CI, .1-.6)). Only eating pureed food remained significant in a multivariable analysis (OR 4.6 (95% CI, 1.6-13.0, P = .01)). CONCLUSION: This report describes outbreaks of legionellosis in two nursing homes, representing the first reported outbreaks of infection caused by Legionella sainthelensi. The association with illness of dietary characteristics indicative of swallowing disorders suggests that aspiration was the most likely mode of infection. The diagnosis of legionellosis should be considered during outbreaks of respiratory infection in nursing homes.

Epidemiological investigation of Salmonella tilene by pulsed-field gel electrophoresis and polymerase chain reaction.

Pulsed-field gel electrophoresis (PFGE) and DNA fingerprinting by the polymerase chain reaction (PCR) were performed on 11 isolates of Salmonella tilene. Five strains were from a cluster of human patients, six from sugar gliders and pygmy hedgehogs kept as family pets or from local pet retailers, and one isolate from the first North American case of S tilene described in Washington State in 1994. The PFGE restriction patterns showed all isolates to be similar. However, PCR using primers to the 16S and 23S rRNA genes of Escherichia coli demonstrated that the Washington State isolate differed from the rest of the other isolates, which were all similar based upon their DNA fingerprint. This study indicates that reliance on one technique alone may be insufficient to show nuances between strains that are, in many respects, closely related.

Myosin light chain phosphorylation and contractile performance of human skeletal muscle.

Twitch tension and maximal unloaded velocity of human knee extensor muscles were studied under conditions of low phosphate content of the phosphorylatable light chains (P-light chains) of myosin and elevated phosphate content, following a 10-s maximal voluntary isometric contraction (MVC). After the MVC, twitch tension was significantly potentiated, with greater potentiation observed at a shorter muscle length (p less than 0.05). The MVC was associated with at least a twofold increase in phosphate content of the fast (LC2F) and two slow (LC2S and LC2S') P-light chains, but this increase was unrelated to muscle length. No significant differences in knee extension velocity were observed between conditions where P-light chains had low or elevated phosphate content. Positive but nonsignificant correlations were noted between the extent of twitch potentiation and phosphate content of individual P-light chains as well as the percentage of type II muscle fibres in vastus lateralis muscle. No significant relationships were determined for myosin light chain kinase activity and either P-light chain phosphorylation or type II fibre percentage. These data suggest that, unlike other mammalian fast muscles, P-light chain phosphorylation of mixed human muscles is not strongly associated with altered contractile performance.

Myosin light chain phosphorylation in intact human muscle.

The phosphate content of the fast (LC2F) and two slow (LC2S and LC2S1) phosphorylatable light chains (P-light chains) in myosin isolated from biopsy samples of rested human vastus lateralis muscle averaged 0.21, 0.28 and 0.25 mol of phosphate per mol of P-light chain, respectively. Following a 10 s maximal contraction, phosphate content was increased by almost 2-fold in the fast and two slow P-light chains. After prolonged, moderate cycling activity phosphate content was only slightly increased in the three P-light chains. These data suggest that, unlike animal skeletal muscle, myosin light chain kinase and phosphatase activities are similar in human fast and slow muscle fibres.