The experimental receptivity ofHelicella (Helicella) itala andCepaea nemoralis (Mollusca,Helicidae) to larvae ofMuellerius sp. andNeostrongylus linearis (Nematoda,Protostrongylidae) from chamois (Rupicapra rupicapra)

Two batches ofHelicella (H.) itala (adult specimens) and two ofCepaea nemoralis (adult and young specimens) were experimentally infected with larvae I (L-I) ofMuellerius sp. andNeostrongylus linearis obtained from the lungs and faeces ofRupicapra rupicapra. In assess larval development, the number and percentage of the total number of larvae (L-I+L-II+L-III) per mollusc were studied, together with the number and percentage of L-III per snail and the days on which the different larval stages were reached. The development ofMuellerius sp. andN. linearis was greater in larvae from faeces. For both species of molluscs, the values for the percentages of the total number of larvae and L-III were higher inN. linearis than inMuellerius sp., but there were no notable differences in the days on which the various larval stages were reached. Both nematodes achieved a greater degree of development in young specimens ofC. nemoralis than in adults. Whether the larvae came from facces or the lungs,H. (H.) itala was a better intermediate host thanC. nemoralis forMuellerius sp. andN. linearis.     

Selection in blood cells from female carriers of the fragile X syndrome: inverse correlation between age and proportion of active X chromosomes carrying the full mutation.

We have studied the patterns of mutation and X inactivation in female carriers of a fragile X mutation, to try to correlate them with various phenotypic features. We used a simple assay, which shows simultaneously the size of the mutation, its methylation status, and DNA fragments that represent the normal active and inactive X chromosomes. We have observed an age dependent process, whereby the 'full' fragile X mutation is found preferentially on the inactive X in leucocytes in adult females, but not in younger ones. This phenomenon was not observed in female carriers of a 'premutation', who have little phenotypic expression. Preliminary data suggest that young females who show preferential presence of a full mutation on the active X in leucocytes may be at increased risk for mental retardation. We have also obtained preliminary evidence for an age dependent decrease in the somatic heterogeneity of full mutations, possibly owing to selection for smaller mutated fragments. If confirmed, the latter phenomenon might account for the known decrease with age of the expression of the fragile site. Our observations suggest that a gene whose expression is affected by the presence of a full mutation (possibly the FMR-1 gene) has a cell autonomous function in leucocytes, leading to a slowly progressive selection for cells where the mutation is on the inactive X chromosome.     

Separation of temperature sensitive and temperature insensitive components of the postsynaptic potentials in the frog motoneurons

Intracellular measurements were made in the in situ spinal cord of the frog at temperatures below 5 degrees C. Responses to volleys in the sciatic nerve, in the descending fibres and in the motor axons were studied. About 30% of the motoneurons responded to sciatic volleys with 1-3 ms segmental latency, which was short enough to assume electrotonic mediation of these responses. Another group of motoneurons responded with 6-8 ms latency, i.e. with the expected delay at chemical synapses at low temperature. Latency distribution of the sciatic-evoked postsynaptic potentials was clearly bimodal in contrast with that found at higher temperatures. Postsynaptic discharges occurred with rather long latency and they were attributed to chemically-mediated excitation. Some of the postsynaptic potentials to descending volleys also occurred with quite short latency, indicating possible electrotonic transmission from supraspinal centres to motoneurons. Latency distribution of the action potentials evoked from the motor axons was bimodal, corresponding to the different, i.e. antidromic and recurrent facilitatory, mechanism of these spikes. Calculated Q10 ratios for the sciatic-evoked reflex discharges and the afferent fibre volleys were about 2.3 and 1.8, respectively. We concluded that cooling helps to separate postsynaptic potentials according to their electrotonic and chemical mediation and that electrotonic excitation does not seem to have a primary role in the generation of postsynaptic discharges initiated by dorsal root volleys in the frog.     

Involvement of the catecholaminergic system in glucagon-induced thermogenesis in Muscovy ducklings (Cairina moschata)

Physiological studies have shown that glucagon is a potential mediator of nonshivering thermogenesis (NST) in birds. The present work was undertaken in order to investigate whether the observed thermogenesis results from a direct action of glucagon on avian thermoregulatory mechanisms or in fact requires the participation of other agents such as catecholamines. Our experiments were performed using cold-acclimated (CA) ducklings which developed muscle NST. A comparison was made with thermoneutral (TN) ducklings of the same age. Our principal results showed that: (1) at ambient temperature (25 degrees C), circulating norepinephrine (NE) was markedly decreased in CA ducklings (-42%), while circulating epinephrine (E) did not undergo any consistent change; (2) in CA and TN ducklings, an intraperitoneal injection of glucagon (360 microg x kg(-1)) was followed after 10 min by prominent lipolysis and a large increase in circulating NE (4- to 6-fold) and E (14- to 17-fold), which was sustained for at least 1 h. The elevation of circulating NE was less pronounced in CA ducklings. The thermogenic action of glucagon in birds is probably indirect and involves at least the mobilization of lipids and sympatho-adrenal stimulation. The changes in peripheral noradrenergic activity during cold acclimation could be associated with adaptive changes leading to NST.     

Developing an expert system for immunophenotypical diagnosis in immunodeficiency. Age-related reference values of peripheral blood lymphocyte subpopulations in Hungary

In the process of developing a decision support system based on flow cytometric data for the diagnosis of immunodeficiency, assessment of lymphocyte subpopulations in human peripheral blood provides the key for further analysis. Samples from 273 'healthy' Hungarian subjects were measured between 1998 and 1999. Immunophenotypic data are compared here (unadjusted for gender) by different age groups: I 0-6 years (n=45); II 7-18 years (n=71); III 19-35 years (n=72); IV 36-55 years (n=48); and V 56-99 years (n=37). Two-color flow cytometric analysis was performed using the Becton Dickinson Simultest IMK Plus kit (CD45/CD14, isotype control, CD3/CD19, CD4/CD8, CD3/HLA-DR, CD3/CD16+56). All lymphocyte subpopulations were measured in all blood samples identically. The quality criteria involved at least 95% of total lymphocytes in the analysis gate, homogenous CD45+ lymphocyte population (minimum of 2000 events in the gate, CD45+ >95%). The frequency of B lymphocytes was the highest, significantly, in the youngest Hungarian subjects, but there were no significant changes with age comparing the data of other II-V age groups. On the other hand, some T subpopulations changed with aging; both CD4 and CD8 subsets varied over time including the elevation of the fraction of activated T cells as well as LGL-NK cells. Some of these changes were significant by statistical tests. Interpretation of flow cytometric data is time-consuming and requires human knowledge of an expert laboratory staff. To facilitate the diagnosis of immunodeficiency, a pilot study aiming at the development of a diagnostic algorithm has been initiated. Algorithm nodes compare the frequency of each lymphocyte subpopulations to the generated reference values. This knowledge-based system describes a short summary report as a result of the comparison, and points to some values requiring further human examination to reach a final conclusion. These reference values and the expert system appear to be a recommended basis for comparing and combining results from different laboratories.     

High-intensity intermittent running training improves pulmonary function and alters exercise breathing pattern in children

We investigated the effects of short duration running training on resting and exercise lung function in healthy prepubescent children. One trained group (TrG) (n = 9; three girls and six boys; age = 9.7 ± 0.9 year) participated in 8 weeks of high-intensity intermittent running training and was compared to a control group (ContG) (n = 9; four girls and five boys; age = 10.3 ± 0.7 year). Before and after the 8-week period, the children performed pulmonary function tests and an incremental exercise test on a cycle ergometer. After the 8-week period, no change was found in pulmonary function in ContG. Conversely, an increase in forced vital capacity (FVC) (+7 ± 4% ; P = 0.026), forced expiratory volume in one second (+11 ± 6% ; P = 0.025), peak expiratory flows (+17 ± 4% ; P = 0.005), maximal expiratory flows at 50% (+16 ± 10% ; P = 0.019) and 75% (+15 ± 8% ; P = 0.006) of FVC were reported in TrG. At peak exercise, TrG displayed higher values of peak oxygen consumption (+15 ± 4% ; P<0.001), minute ventilation (+16 ± 5% ; P = 0.033) and tidal volume (+15 ± 5% ; P = 0.019) after training. At sub-maximal exercise, ventilatory response to exercise was lower (P = 0.017) in TrG after training, associated with reduced end-tidal partial oxygen pressure (P<0.05) and higher end-tidal partial carbon dioxide pressure (P = 0.026). Lower deadspace volume relative to tidal volume was found at each stage of exercise in TrG after training (P<0.05). Eight weeks of high-intensity intermittent running training enhanced resting pulmonary function and led to deeper exercise ventilation reflecting a better effectiveness in prepubescent children.     

The complete genome sequence of a new necrovirus isolated from <Emphasis Type="Italic">Olea europaea</Emphasis> L.

Summary. The complete nucleotide sequence of a virus isolated from Olea europaea L. (GP isolate), previously identified as an isolate of Tobacco necrosis virus D (TNV-D) based on its coat protein sequence, was determined. The viral RNA genome consists of 3683 nucleotides and contains five open reading frames. The putative RNA-dependent RNA polymerase shows 91.2% amino acid identity with that of an isolate of Olive latent virus 1 (OLV-1) and the coat protein reveals highest sequence identity with that of TNV-D. Based on the deduced genome organization and phylogenetic analysis of predicted functional translation products with that of other necroviruses, the GP isolate genome appears to represent an example of a new virus arisen by gene exchange and is proposed to be a new necrovirus, provisionally named Olive mild mosaic virus.     

Theory of mind and motion perception in schizophrenia

This study investigated the relationship between theory of mind (ToM) deficits and visual perception in patients with schizophrenia (N=52; 17 remitted and unmedicated) compared with healthy controls (N=30). ToM was assessed with the Eyes Test, which asked participants to choose which of 4 words best described the mental state of a person whose eyes were depicted in a photograph. Visual perception was evaluated with form and motion coherence threshold measurements. Results revealed that patients with schizophrenia (both remitted and nonremitted) showed deficits on the Eyes Test and the motion coherence task. ToM dysfunctions were associated with higher motion coherence thresholds and more severe negative symptoms. This suggests that ToM deficits are related to motion perception dysfunctions, which indicates a possible role of motion-sensitive areas in the pathophysiology of schizophrenia.     

Evaluation of the mutagenic and cytotoxic effects of mercurous chloride by the micronuclei technique in golden Syrian hamsters

The aims of this study were to evaluate the mutagenic and cytotoxic activity of mercurous chloride by the micronucleus technique in vivo on the bone marrow of golden Syrian hamsters after a single i.p. drug administration. Forty male golden Syrian hamsters were classified into eight groups: negative control, positive control and six groups treated with different doses of mercurous chloride (1.25, 2.5, 5, 10, 20 and 40 mg/kg). The negative control was injected with physiological saline i.p. and the positive control with cyclophosphamide at a dose of 80 mg/kg i.p. With respect to mutagenic effect, the average number of micronucleated polychromatic erythrocytes (MPE) in hamsters treated with different doses of mercurous chloride was not significant compared with the negative control. With respect to cytotoxic effect, the average polychromatic erythrocyte/red blood cell ratio showed a significant decrease when the doses were higher than the 2.5 mg/kg dose compared with the negative control. In conclusion, this preliminary study shows a cytotoxic effect but not a mutagenic effect of calomel in vivo at one time point (24 h).     

Hepatitis E in the south west of France in individuals who have never visited an endemic area

A total of 431 consecutive patients from the Midi Pyrenees area with acute hepatitis with unknown etiology in 2001-2002 were tested for the presence of immunoglobulin G-class (IgG) anti-hepatitis E virus (HEV) antibodies. Forty-six (10.7%) had anti-HEV IgG, and the results were questionable for a further 17 (3.9%). Real time PCR based on TaqMan detection was used to identify HEV genome fragments in the serum of patients with positive or questionable anti-HEV serology. HEV RNA was found in 25.4% of cases. All amplification products were sequenced and analyzed. Phylogenetic analysis revealed that all the strains were genotype 3. In conclusion, virological and epidemiological data indicate that genotype 3 viruses are circulating in the south west part of France (Midi-Pyrenees) in patients with acute hepatitis and who have not visited recently areas in which HEV is endemic.