Daily cough frequency in tuberculosis and association with household infection.

SETTING: Although cough in tuberculosis (TB) is presumed to be important for transmission, there is little objective supporting evidence. OBJECTIVE: To describe 24-h cough frequency in a group with TB, and investigate associations with household rates of infection. DESIGN: Patients with a new diagnosis of pulmonary TB underwent 24-h cough frequency measurement at or just before initiation of anti-tuberculosis treatment. A group with latent Mycobacterium tuberculosis infection (LTBI) acted as controls. Rates of infection among household contacts of sputum smear-positive TB were measured using the interferon-gamma release assay and the tuberculin skin test, and compared with variables relating to the contacts themselves, and to the index case, including cough frequency. RESULTS: Daily cough frequency in TB patients (n = 44) was variable (geometric mean [GM] 174, interquartile range [IQR] 68-475 coughs/24 h), higher than in LTBI (n = 17; GM 19 coughs/24 h, IQR 8-53; P < 0.001), and higher during the day than overnight (GM 8.9 coughs/h, IQR 4.1-19.0 vs. GM 2.9 coughs/h, IQR 0.7-13.4; P < 0.0001). Also, 24-h cough frequency in TB was associated with sputum smear status (P = 0.040), but not smoking (P = 0.475). Multivariable logistic regression confirmed that infection in contacts was independently associated with index case sputum smear grade (P = 0.014) and cough frequency (P = 0.022). CONCLUSION: Measurement of 24-h cough frequency in pulmonary TB helps predict infectiousness and transmission patterns.

The use of ethnically specific norms for ventilatory function in African-American and white populations.

BACKGROUND: In the USA, different standards are usually set for spirometric values in African-American and white populations. It is unclear to what extent the lower lung function found in African-Americans is 'normal' in the sense of having no adverse consequences. METHODS: African-American and white participants in the Atherosclerosis Risk in Communities (ARIC) limited access data set, from four communities in the USA had spirometric testing at baseline beginning in 1986 and were followed up to assess survival to the end of 2002. RESULTS: Forced Expiratory Volume in 1 s (FEV(1)) and Forced Vital Capacity (FVC) were lower in the African-American than the white sample both for men and women and adjustment for potential confounders had little effect on the estimated difference {difference in FVC after adjustment: men, -0.68 l [95% confidence interval (95% CI) -0.75 to -0.61]; women, -0.41 l (95%CI -0.45 to -0.36)}. The FEV(1)/FVC ratio was slightly greater among African-American than white participants [difference: men, 1.5% (95%CI 0.7-2.1); women, 1.7% (95%CI 1.1-2.2)]. After adjustment for age and height, survival was similar in each ethnic group for any given level of FVC before and after adjustment for potential confounders. The hazard ratio for African-American compared with white participants was 1.24 for men (95% CI 0.91-1.69) and 0.96 for women (95% CI 0.66-1.38). CONCLUSIONS: A given FVC has the same prognostic significance for 'normal' African-American and white participants. It is inappropriate to use ethnic norms when assessing prognosis.

Measurement of quality of life in alcohol-dependent subjects by a cancer symptoms checklist.

There are few studies of Quality of Life measures (QoL) in alcohol-misusing patients. The present study addresses this deficiency. The sample consisted of 60 (39 men, 21 women) alcohol dependent subjects defined by DSM-IV criteria (American Psychiatric Association, 1994). At baseline (4-5 days after admission and detoxification) sociodemographic data were collected, and three questionnaires were administered: the Rotterdam Symptoms Checklist (RSCL), the Severity of Alcohol Dependence Questionnaire (SADQ), and Alcohol Problems Questionnaire (APQ). QoL scores for dependent alcoholics both for physical and psychological measures were significantly worse (higher) than those reported for a variety of cancer patients. Psychological symptom scores were higher than physical symptoms at baseline. Correlations of RSCL scores to both SADQ and APQ were greater for RSCL physical compared to psychological symptom scores. The subjects were followed up at 12 weeks when the RSCL was re-administered and relapse status ascertained. Fifty-eight (97%) subjects were successfully contacted at 12 weeks of whom 36 (62%) had relapsed. After a repeated measures ANOVA psychological and physical symptom subscores were statistically significantly improved as a result of not relapsing to heavy drinking. There was no significant change in scores in the relapse group when baseline and week 12 scores were compared. The RSCL measure is a useful QoL assessment tool in alcohol-dependent subjects.

Efficacy of diethyl methylbenzamide (deet) against Aedes dorsalis and a comparison of two end points for protection time.

The repellent deet (N,N-diethyl-3-methylbenzamide) was tested against the mosquito Aedes dorsalis in a coastal salt marsh in California. The experimental design incorporated a multiple regression model, sequential treatments and a proportional end point (95%) for protection time. The ED95 (95% effective dose) and 4-h ED95 were estimated at 0.05 mg/cm2 and 0.09 mg/cm2, respectively. The 0.05 mg/cm2 protection time and 0.10 mg/cm2 protection time were estimated at 0.2 h and 4.4 h. The decay constant and half-life were estimated at 0.17 h-1 and 4.1 h. The design and analysis of repellent field trials are discussed.

A field trial of ethyl hexanediol against Aedes dorsalis in Sonoma County, California.

The repellent ethyl hexanediol (2-ethyl-1,3-hexanediol) was tested against the mosquito Aedes dorsalis in a coastal salt marsh in California. The experimental design incorporated a linear regression model, sequential treatments and a proportional end point (95%) for protection time. The protection time of 0.10 mg/cm2 ethyl hexanediol was estimated at 0.8 h. This time is shorter than that obtained previously for deet (N,N-diethyl-3-methylbenzamide) against Ae. dorsalis (4.4 h).

Lipid and salt effects on carbocyanine dye-induced photo-voltages in bilayer membranes.

Voltage transients induced by flash illumination of bilayer membranes with sorbed dye, 3,3' -dimethyl-2,2' -oxacarbocyanine chloride (diO-C1-3-CI), vary with membrane lipid composition and aqueous solution salt concentration. The voltage transients are probably induced by physical movements of sorbed dye molecules following photo-isomerization. Increased salt (NaCl and NaBr) concentrations in the aqueous solutions reduced the photo-voltage amplitudes by reducing the amount of dye sorbed to the membranes, and by decreasing the effective membrane thickness. The photo-voltage risetimes and falltimes varied systematically with salt concentration and membrane lipid composition, reflecting structural changes in the membrane's surface layer.