Antigenic diversity of the asexual developmental stages of Eimeria tenella

Total polypeptides from unsporulated and sporulated oocysts, sporozoites and the first two generations of merozoites of Eimeria tenella were fractionated by electrophoresis through polyacrylamide gels. The parasites are complex and the arrays of polypeptides differ for each of the developmental stages indicating that there is stagespecific control of gene expression. In particular, first generation merozoites display a markedly different polypeptide profile to that of either sporozoites or second generation merozoites. Changes in antigenicity during sporulation and the antigenic relationships between the three asexual zoite stages were examined by probing electroblotted polypeptides with a panel of antisera raised in rabbits to purified preparations of each stage. Antigenic cross-reactivity is well maintained throughout sporulation even though the sizes of antibody-reactive polypeptides change. In contrast there is a marked lack of cross-reactive epitopes between sporozoites, first and second generation merozoites.     

Working alongside the general practitioner: a child psychiatric clinic in the general practice setting

A monthly child psychiatric clinic was established in a primary health care centre in order to offer a more accessible service to patients, and to improve liaison with primary health care professionals. Compared with the base child guidance unit, at the health centre there was a better first attendance rate, a much higher proportion of referrals from health professionals especially general practitioners, and an increased proportion of younger children referred. If further follow-up was necessary at the child guidance unit the attendance rate was very good. The service provided, although not reducing the need for a main multidisciplinary base, offered an acceptable and accessible opportunity for children with psychological problems to be assessed and treated, and for the referring professionals to have easy communication with the child psychiatrist.     

Free testosterone levels in umbilical‐cord blood predict infant head circumference in females

Aim Fetal androgens influence fetal growth as well as postnatal neurocognitive ability. However, to our knowledge, no published study has prospectively examined the impact of early‐life androgens on infant brain growth. We report the association between circulating fetal androgen levels, measured from umbilical‐cord blood at birth, and a proxy measure of brain growth: head circumference. Method Participants were 82 unselected female infants from a large representative birth cohort (mean gestational age 39.4wks, SD 1.7). Umbilical‐cord blood was obtained at birth and analysed for androgen concentrations (total testosterone, androstenedione, dehyrdroepiandrosterone, and its sulphated metabolite). Head circumference and two other measures of growth – weight (mean 3311.4g, SD 461.3) and length – were measured within 3 days of birth and again at approximately 1 year of age (mean age 13.1mo, SD 1.1). Results Multivariate linear regressions found an inverse association between levels of free testosterone and growth in head circumference (correlation=?.24), even when adjusting for sociodemographic/obstetric covariates and head size at birth. Growth in weight and length could not be predicted by free testosterone concentration. Interpretation This is the first report of an association between prenatal androgen levels and postnatal growth in head circumference. These findings suggest that early‐life androgens may impact brain development during infancy.     

Daytime sleepiness, psychomotor performance, waking EEG spectra and evoked potentials in women with severe premenstrual syndrome

We assessed daytime sleepiness using objective and subjective measures in women with severe premenstrual syndrome (PMS) compared with women without significant premenstrual symptoms. Nine women with severe PMS and eight controls (aged 18−40 years) completed a laboratory-based daytime protocol including the maintenance of wakefulness test (MWT), psychomotor vigilance task (PVT), quantitative waking electroencephalogram (EEG), auditory and visual event-related potentials (ERPs), and sleepiness and mood scales during the mid-follicular and late-luteal (premenstrual) phases of the menstrual cycle. In association with increased perceived sleepiness, fatigue and other premenstrual symptoms in the late-luteal phase, women with PMS performed more poorly on the PVT, with increased lapses and slower reaction times ( P  <   0.05), compared with the follicular phase and controls. However, there were no significant group or menstrual phase differences in latency to sleep on the MWT. Waking spectral EEG power and ERP measures also did not differentiate PMS women when symptomatic. Both groups of women displayed increased spectral power in the delta/theta frequencies (2−6 Hz) and fast alpha frequency (11−12 Hz) in the late-luteal phase relative to the follicular phase. Trait-like differences were apparent in that women with PMS had increased beta1 (12−16 Hz) power and smaller P300 amplitude than controls in both menstrual cycle phases. Our findings indicate that women with severe PMS are subjectively sleepy and fatigued, and show psychomotor slowing when symptomatic compared with when they are symptom-free and compared with controls. However, the ability to maintain wakefulness under soporific conditions, spectral properties of waking EEG and cognitive processing do not vary in synchrony with premenstrual symptoms.     

Biochemical study and in vitro insect immune suppression by a trypsin‐like secreted protease from the nematode Steinernema carpocapsae

A trypsin‐like serine protease was purified by gel filtration and anion‐exchange chromatography from the excretory‐secretory products of parasitic phase Steinernema carpocapsae. The purified protease exhibited a molecular mass of about 29 kDa by SDS–PAGE and displayed a pI of 6·3. This protease exhibited high activity with trypsin‐specific substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide and was highly sensitive to aprotinin and benzamidine. The purified trypsin protease digested the chromogenic substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide with K_m, V_max and k_cat values of 594·2 μm , 0·496 μm /min and 22·8/s, respectively. The optimal pH and temperature for protease activity were 9 and 30°C, respectively. Internal amino acid sequencing yielded 150 amino acids and these were homologous to other trypsin sequences. In vitro investigation was carried out to monitor prophenoloxidase suppression in Galleria mellonella by the purified protease; about 38·9–52·6% suppression of prophenoloxidase was observed. The purified protease affected insect haemocyte spreading, causing cells to become spherical or round. Protease‐treated actin filaments were highly disorganized in haemocytes. In vitro, G. mellonella haemocytes recognized infective juveniles of Heterorhabditis bacteriophora; however, S. carpocapsae and Steinernema glaseri were not recognized. We provide experimental evidence that the purified trypsin has the potential to alter host haemocytes, actin filaments and to inhibit host haemolymph melanization.