SummaryAnecdotal reports have suggested that reduced efficacy of pediculicides against Pediculus humanus capitis could be related to resistance to treatments.Ovicidal and pediculicidal activities of 0.5% malathion and 0.3% d-phenothrin lotions 'were tested in an experimental model of P humanus capitis grown on rabbits to ensure that the two treatments were pharmacologically equipotent. We then did a randomised controlled trial in which the lotions were administered to 193 P humanus capitisinfested schoolchildren (malathion, 95; d-phenothrin, 98). Success rate was defined as the absence of both live lice and viable nits. Before treatment, live lice were collected and subjected to a pediculicidal test. Pharmacological tests showed 100% killing of the rabbit-grown nits and lice after exposure to both pediculicides. On day 1 of the controlled trial, the success rate was 92% in the malathion group (95% CI, 0-86-0.97) and 40% in the d-phenothrin group (0.30-0.49) (pc0.0001); on day 7, it was 95% in the malathion group These results suggest an acquired resistance to d-phenothrin in the schoolchildren tested, since all other conditions of the administration of insecticides were standardised.

Background/Aims-A study was undertaken of liver biopsy samples from 229 consecutive patients with alcoholic or hepatitis C virus related cirrhosis who were prospectively followed until January 1996 to evaluate the influence of liver iron content on survival and the occurrence of hepatocellular carcinoma. Conclusions-These results suggest that hepatic iron enhances liver lesions caused by alcohol but not those caused by hepatitis C virus. (Gut 2000;46:277-282) Methods-Hepatic

The cases of one hundred and forty-one patients (85 males, 56 females) treated for hyperleucocytic acute lymphocytic leukemia (H-ALL) were reviewed. In all cases the initial white blood cell count was over 100,000/cu mm. One hundred patients (71%) attained complete remission (CR). The median duration of CR was six months and the median survival was nine months for all patients and 11 months for those who attained CR. Age, initial hemoglobin, and the height of initial white blood cell count over 100,000 had no significant prognostic value. Relapses occurred earlier in patients with a mediastinal mass. The results depended on the treatment used. With modern treatment, including more intensive chemotherapy and central nervous system prophylaxis, CR rate increased from 65% to 81% and median duration of CR improved from four months to ten months. The most important prognostic difference was related to the sex: CR rate was higher (78.5% vs. 66%) and median duration of CR and hematological remission was longer for females (nine months vs. six months and ten months vs. 6.5 months, respectively). This difference only appeared with modern treatments, however: before 1972 the median duration of CR was four months for both sexes, and after 1972, it was eight months for males and 17 months for females. This difference could be explained by the site of the first relapse, which was testicular in only 2% of cases before 1972 and 27% (47% of the males who relapsed) after 1972.

Concentrations of magnesium and potassium in erythrocytes and plasma were determined in a population of 381 unselected elderly men and women, most of them in their eighties. The effects of biological factors (age, sex, weight) and a large set of pathological conditions, malignant or not, were examined. Analyses of variance showed a relation between age and concentrations of plasma potassium and between weight and concentrations of plasma magnesium. The chi-square test showed correlations between low concentrations of plasma magnesium and diabetes, abuse of alcohol and tobacco, and also between low values for erythrocyte magnesium and hypertension. Low values for plasma potassium were correlated with hypertension whereas high values were correlated with cardiovascular disease. Although some of the differences in the mean concentrations observed were statistically significant, these differences were always small. Most interesting was the distribution of the concentrations of the cations. This study shows that assays of both of these cations in erythrocytes were better than assays in plasma to evidence a deficiency. Indeed, about 20% of the studied population had low concentrations of both erythrocyte potassium and magnesium, whereas 2 and 10% had low values for plasma potassium and magnesium, respectively. This study underlines the large prevalence of magnesium and potassium deficiencies in the elderly, an observation we could not attribute to pathology or treatment. Routine electrolyte studies therefore appear to be justified in aged human subjects.

The complete hematological remission (CHR) rate, duration of remission and survival were studied in relation to age, peripheral blast cell (PBC) count, presence or absence of tumor masses, cytological type, and treatment in 650 patients with acute lymphoblastic leukemia. Prognostic factors were considered separately and divided into prognostic classes. Age and PCB count correlated with both the rate and the duration of CHR. This correlation was still observed for more recent treatment schedules though it appears to be becoming progressively less significant. Meningeal relapses were more common in patients less than 1 year old and in those with a high PCB count. It is suggested that stratification of patients according to such factors as age, PCB count, presence or absence of tumor, and cytological type might be necessary for the design of new treatment protocols and for the evaluation of their results.