Effects of the avermectin analogue MK-243 on vitellogenesis and reproduction in the ixodid tick,Amblyomma hebraeum

A dose-dependent reduction in weight of total egg mass and a slightly increased oviposition latency were observed following injection of the avermectin, analogue MK-243 (4-epi-methylamino-4-deoxyavermectin B₁) directly into the haemocoel of engorged femaleAmblyomma hebraeum Koch (Acari: Ixodidae). Egg laying was almost completely inhibited at 100 g/kg body weight. MK-243 markedly inhibited ovary development and vitellogenesis. Ticks treated with 100 g MK-243/kg also had one-tenth the haemolymph ecdysteroid concentration compared to controls 10 days post-engorgement. Thus, among its other effects on ticks, the avermectins also inhibit the process of vitellogenesis.     

Inter-relationships between pituitary-adrenal hormones and catecholamines during a 6-day Nordic ski race

The aim of the study was to investigate the inter-relationships between pituitary-adrenal hormones and catecholamines during a prolonged competition over 6 days. Plasma adrenocorticotropic hormone (ACTH), cortisol (C), beta-endorphin (beta EP), free and sulphated adrenaline (A) and noradrenaline (NA) were measured in 11 volunteer male subjects during a national Nordic-ski race (323 km). Blood samples were obtained before the competition in the evening as control (D0), and before and after each day's racing (D1-D6). The mean daily heart rate (fc) was calculated from fc values recorded every minute during the race. The results showed the following: changes in mean fc [from 147 (SEM 3) to 156 (SEM 3) beats.min-1 according to the day] were not significant during the race. Diurnal variations in ACTH, beta EP and C were no longer apparent after the race: evening levels were higher than their respective D0 values during the race, except on D3 when there was a lack of response to exercise in the three hormones. Unlike ACTH and beta EP, pre- and postexercise C values on D1 and D2 were higher than those on the subsequent days (P less than 0.001). In contrast, there was a progressive accumulation of A and NA in pre- and postrace concentrations which reached a plateau in about 4 days. Positive correlations between exercise responses in ACTH, C and beta EP were found especially on D3 and D6 (P less than 0.001) but there were no significant correlations between catecholamines and the other three hormones. Thus, prolonged competition over 6 days evoked different control mechanisms for hormones of the pituitary-adrenal axis and catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of some growth regulators on in vitro tuberization in Dioscorea alata L. ‘Brazo fuerte’ and D. abyssinica Hoch.

Summary Nodal cuttings of Dioscorea alata L. Brazo fuerte and D. abyssinica Hoch. were cultured in vitro to assess the influence of NAA on the production of microtubers. In D. alata, high concentrations of NAA (27 and 54 M) favored the production of large microtubers, whereas the highest number of microtubers was obtained with 2.7 M. D. abyssinica was found to be more sensitive to NAA since concentrations higher than 0.27 M promoted the growth of callus on the root system. In this species, the production of the largest microtubers was obtained at 2.7 M whereas the number of microtubers was not affected by any concentration tested. In D. alata, the effects of ABA and BAP were also evaluated. The weight of the microtubers increased with increasing concentrations of ABA. This effect, however, was observed only on expiants cultured under 8 h photoperiod, but not on those cultured under 16 h. Finally the presence of BAP at concentrations as low as 0.22 M adversely affected the survival of the explants.Abbreviations ABA abscissic acid - BAP benzyl aminopurine - NAA -naphthaleneacetic acid - MS Murashige and Skoog     

Unequal Day-Night Terbutaline I.V. Dosing in Acute Severe Asthma: Effect on Nocturnal Bronchial Patency, Heart Rate, and Arterial Pressure

Our study investigated the differential effects of continuous or unequal day-night terbutaline dosing on circadian bronchial patency, heart rate, and arterial pressure in severe acute asthma. Forty-five hospitalized asthmatic patients (19 women and 26 men, mean age 45.4 years, mean weight 63.5 kg) were included in this multicenter study. Three groups of patients (corresponding to three dosing schedules) were randomized; the three groups were comparable, since no statistically significant difference was detected in the age, weight, or peak expiratory flow values at the beginning of the study. In order to reach immediately the concentrations of terbutaline corresponding to the desired unequal day-night concentrations, a theoretical pharmacokinetic simulation was done to predict the outcome in terms of the plasma concentrations after the three dosing regimens; the results of this simulation allowed us to calculate the initial bolus dose to be given over 5 min to groups A, B, and C, i.e., 1.47, 2.94, and 4.41 Mg/kg, respectively. This bolus was given to all patients at 0700 h, the beginning of the study. The patients were randomly divided into three groups (A, B, C) receiving one of these treatments: 0.0111 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate delivered by an electrical pump and 0.0222 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (A) (one third the total daily dose during the day and the remaining two thirds at night), 0.0166 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0166 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (B) (one half the total daily dose during the day and the remaining one half at night), or 0.0222 mg/kg of terbutaline i.v. from 0700 to 1900 h at a constant rate and 0.0111 mg/kg of terbutaline i.v. from 1900 to 0700 h at a constant rate (C) (two thirds the total daily dose during the day and the remaining one third at night). Since acute severe asthma could not be treated without steroids, a 40 mg dose of SoluMedrol was injected into all patients at 0700. Peak expiratory flow rate, heart rate, systolic arterial pressure, and possible side effects were recorded at different times during the 24-h scale: 0700, 1000, 1300, 1600, 1900, 2300, 0300, and 0700 h. Our results have shown a significant therapeutic effect of terbutaline i.v. dosing in severe acute asthma whatever the unequal daynight dosing, but did not demonstrate the efficacy of one of the three dosing schedules over the others.     

Protein kinase activities during maturation in xenopus laevis oocytes

Protein kinase activities have been compared in ovarian oocytes and in ovulated eggs of $\text{Xenopus laeyis}$.In ovaries and ovarian oocytes, we have detected, in addition to an already known (1) cyclic AMP stimulated phosphoprotein kinase, a second very active phosphoprotein kinase which is cAMP-independent.Besides these two activities, a third protein kinase activity becomes detectable after maturation and ovulation: it is a cAMP and cGMP-dependent histone kinase.     

Gas chromatography-mass spectrometry analysis of tert.-butyldimethylsilyl derivatives of 2-acetylaminofluorene and metabolites in isolated rat hepatocytes

A new technique for the conversion of 2-acetylaminofuorene and several ring-hydroxylated metabolites to mono- and di-tert.-butyldimethylsilyl derivatives was developed to permit their analysis by gas chromatography-mass spectrometry in order to quantify the metabolism of 2-acetylaminofluorene incubated in freshly isolated rat hepatocytes. This new gas chromatography-mass spectrometry method allowed the separation, identification and quantitation of seven known metabolites comprising five arylhydroxylated compounds, 2-aminofuorene and N-hydroxy-2-acetylaminofuorene.Abbreviations 2-AAF 2-acetylaminofluorene - 2-AF 2-aminofluorene - DMF dimethylformamide - El electron impact ionization - FBS fetal bovine serum - GC-MS gas chromatography-mass spectrometry - MtBSTFA N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide - MU methylene unit - N-OH-2-AAF N-hydroxy-2-acetylaminofluorene - 4,4-OH-BP 4,4-hydroxybiphenyl - tBDMS tert.-butyldimethylsilyl     

Inversion (14)(q12qter) or (q11.2q32.3): The most frequently acquired rearrangement in lymphocytes

Summary In a large study of chromosome rearrangements occurring in human lymphocytes from normal subjects, inv (14)(q12qter) or (q11.2q32.3) is found to be the most frequent, affecting 0.15% of mitoses. The same inversion is observed in the lymphocytes of the chimpanzee, indicating the ancestry of this inversion. It is not induced by ionizing radiations, and its frequency may be increased in Fanconi anemia, but not in ataxia telangiectasia. It may represent one of the steps of the process of leukemogenesis.     

18q- Syndrome resulting from a tdic(14p;18q)

Summary A case of 18q- syndrome due to a de novo tdic(14p;18q) is presented. The interest of this observation lies in the rarity of stable dicentric chromosomes arising from reciprocal translocations between autosomes.