Suppression of heparinization of central venous catheters between cycles of chemotherapy

A phase I study to evaluate heparinization of tunnelled subclavian catheters (TSC) was conducted in 42 patients who each had a TSC for chemotherapy. They were enrolled in the study from August 1994 to December 1995. The inclusion criteria were: age 18–70, no general anticoagulant treatment, TSC used only for chemotherapy, informed consent. Heparinization was performed at the end of each cycle and then at increasing intervals: 11, 13, 15, 17, 19, and 21 days. A 21-day interval was intended to mimic the suppression of heparinization between cycles. Heparinization was performed with a 250 IU/ml heparin solution. Anti-Xa activity was studied before each heparinization. For each interval, at least 5 patients were followed up for two cycles. If no blockages were present progression to the next step was authorized. If one blockage was observed 5 additional patients were required to have their TSCs heparinized after the same interval. Two blockages (block) after the same interval meant that the previous interval was recorded as the longest tolerable. There were no blocks with the 11-day interval (6 patients), 1 block after 13 days (10 patients), 1 block after 15 days (10 patients), and no blocks after 17 days (5 patients), 19 days (6 patients), or 21 days (5 patients). The median anti-Xa activity (curative rate 0.2–0.6) was, respectively 11 days 6.74; 13 days 5.47; 15 days 4.71; 17 days 3.61; 19 days 3.67; 21 days 5.10 (NS). Heparinization between two cycles of chemotherapy is unnecessary. A high level of heparin activity persisted constantly inside the catheter lumen through the 3-week observation period.     

Volatile substance misuse among high school students in South America

This article summarizes data from a 2004 study of over 300,000 high school students (aged 13-18 years) in nine South American countries. A probabilistic sample targeted urban secondary schools, utilizing a self-administered questionnaire on prevalence and frequency of substance use. Multivariate analysis showed that volatile substances were the first or second most commonly reported substances used after alcohol and cigarettes in all countries (lifetime prevalence range: 2.67% [Paraguay] to 16.55% [Brazil]). Previous studies have highlighted volatile substance misuse among street children, whereas this study demonstrates that it is common among South American high school students.     

The decision to treat moderate hypertension: repetition of office visits or ambulatory monitoring of arterial pressure?

World Health Organization (WHO) recommends antihypertensive therapy for mild to moderate hypertensive patients after 3 or more visits. We tested the hypothesis that an ambulatory blood pressure recording could also help to decide which patient need therapy. Blood pressure was measured in 89 essential, uncomplicated, hypertensive patients (diastolic (DBP): 90-110 mmHg, mean age: 41 +/- 13 years), with a mercury sphygmomanometer at 3 visits and with an ambulatory blood pressure recorder (Spacelabs) during 12 hours. According to WHO recommendations, patients were classified "WHO+" if they need a treatment (n = 44) and "WHO-" if they did not. The mean ambulatory DBP of each subject was compared to the arbitrary limit defined as the mean +2 standard deviations of the ambulatory DBP of a population of normotensive subjects in the same decade and same sex: patients with ambulatory DBP above this limit were defined "AMB+" (n = 27), the others were "AMB-". Ten patients were "WHO- AMB+" and 24 were "WHO+ AMB-". These discordances were independent of age, body weight, duration of hypertension, variability of ambulatory systolic and diastolic blood pressure defined by the standard deviation. By contrast, the difference between the measurements of the simultaneous blood pressure measurements performed with the two methods (mercury sphyngmomanometer and Spacelabs) 2 times by each patient could explain in part these discrepancies. The Spacelabs underestimates DBP measured with the mercury sphyngmomanometer in patients "AMB-" but not in patient "AMB+".(ABSTRACT TRUNCATED AT 250 WORDS)