Application of Doehlert design to determine the combined effects of temperature, water activity and pH on conidial germination of Penicillium chrysogenum.

AIMS: The influence of temperature, water activity and pH on the time necessary for germination of 90% of Penicillium chrysogenum conidia inoculated (T90) was determined. METHODS AND RESULTS: A new experimental device was developed for easy monitoring of the germination process. Experiments were carried out according to a Doehlert matrix at 11-31 degrees C, 0.86-0.98 water activity (a(w)) and pH 3.5-6.5. In these conditions, a second order polynomial relationship between T90 and the environmental factors was established for the different humectants used throughout this study (e.g. glycerol and sorbitol) with regression coefficients close to 0.97. CONCLUSIONS: For both humectants, the major effect of temperature and water activity on T90 was highlighted, whereas the effect of pH on T90 in these experimental conditions was not significant. The combined effect of temperature and water activity on T90 was also demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: Both the experimental set-up and the Doehlert matrix were well suited to determine the influence of environmental factors on mould germination.

Prediction of conidial germination of Penicillium chrysogenum as influenced by temperature, water activity and pH.

AIMS: Conidial germination of Penicillium chrysogenum was carried out under operating conditions compatible with a pastries manufacturing process. METHODS AND RESULTS: A range, limited by two experimental values, was defined for each environmental factor tested: temperature (15 or 25 degrees C), water activity (0.75 or 0.85) and pH (3.5 or 5.5). A closed device was made, which maintained an equilibrium between water activity of the culture medium and atmospheric relative humidity during 25 days, to follow spore germination. The combined effects of temperature, water activity and pH on spore germination were studied by applying factorial design methodology. CONCLUSIONS: Higher rates of spore germination were associated with a high level of water activity. The incubation temperature also had a positive effect. A significant positive interaction between water activity and temperature was observed. Under these specific experimental conditions, pH did not have a significant effect on conidial germination. SIGNIFICANCE AND IMPACT OF THE STUDY: A model describing the behaviour of fungal conidia is proposed.

Empirical analysis of the selective attention and associated behavior checklists of the Aggregate neurobehavioral student health and educational review.

For 111 referred children, the Behavior Observation (BO) and the Selective Attention (SA) components of the Aggregate Neurobehavioral Student Health and Educational Review (ANSER) were completed by mothers and teachers and the Pediatric Examination of Educational Readiness at Middle Childhood was completed by the pediatrician. Smaller samples were used to study concurrent validity. The questionnaires presented high internal reliability. Factor analyses of the BO questionnaires resulted in a common primary factor of "Aggressiveness" for ratings by mothers and teachers. For the SA, "Hyperactivity" (mothers) and "Inattention" (teachers) accounted for the majority of variance. There were modest correlations between teachers and mothers. The correlation between the pediatrician and teachers reached the highest value. The BO-Teachers form was significantly related to the Teacher Report Form and the Conners Teacher Rating Scale. The authors concluded that the ANSER presents concurrent validity for teacher ratings, items predictive of atypical behavior, and a unique pool for defining a subgroup of children with attentional disorders. The limited relationship between mothers and teachers may be ascribed to different interpretations of the same items.

Prevalence of sexually transmitted diseases in juvenile prostitutes and street youth.

Four groups of adolescents - 35 juvenile prostitutes, 36 street youth, 31 monogamous sexually active adolescents and 35 non-sexually active adolescents - were studied between January 1, 1988 and December 31, 1988 for the presence of sexually transmitted diseases and other genital pathogens. The high prevalence of sexually transmitted diseases found in the juvenile prostitutes (Neisseria gonorrhoeae, 49%; Chlamydia trachomatis, 83%) is in contrast to other studies, which document much lower rates of infection. This could be due to the fact that there are few studies done on juvenile prostitutes as a well defined group. Despite high risk sexual behaviour, the consistent use of contraception was low. No contraceptives were used by 57% of the juvenile prostitutes and 85% of the street youth. None of the adolescents sought medical attention although 48% of the juvenile prostitutes and 53% of the street youth had genital symptoms. It appears that the present public health education and health care delivery do not reach this high risk population.

Phenylethylaminergic mechanisms in attention-deficit disorder.

Urinary excretion (24-hr) of beta-phenylethylamine (PEA), phenylacetic acid (PAA), phenylalanine (Phe), and p-tyrosine (Tyr), and plasma levels of PAA, Phe, and Tyr were examined in 18 normal children and 26 children diagnosed as having attention-deficit hyperactivity disorder (ADHD). The results indicated that urinary excretion (expressed per g of creatinine) of free and total PEA was significantly lower in the ADHD patients, and plasma levels of Phe and Tyr were also decreased in the ADHD subjects compared with the normal controls.

The role of drug-induced illness in admissions to an intensive care unit.

All patients admitted during a 33-month period to a multidisciplinary intensive care unit were prospectively studied in order to determine the incidence and severity of drug-induced illness leading to the admission. The role of underlying diseases was assessed and the avoidability of drug-induced illness considered. Out of 1651 patients, 97 (5.88%) were admitted because of drug-induced illness; 74 of these had serious underlying diseases. 13 (13.4%) of the 97 patients died, but underlying diseases accounted for 4 of the 13 fatalities. In nearly half of the cases, the drug-induced illness appeared potentially avoidable.