Phagocytic function in cyclists: correlation with catecholamines and cortisol.

Flow cytometer measurements were made of the basal variations in peripheral blood functional monocytes and granulocytes over the course of a training season (January to November) of a cycling team. Parallel determinations were made of plasma concentration of catecholamines (chromatography) and cortisol (RIA) in a search for neuroendocrine markers. The results showed the greatest phagocytic capacity to occur in the central months (March, May, and July), coinciding with the greatest number and highest level of competitive events with good correlation with a peak in epinephrine during these months (r(2) = 0.998 for monocytes and r(2) = 0.674 for granulocytes). No good correlations were found between phagocytosis and norepinephrine or cortisol. The highest values for phagocytosis and epinephrine concentration were found in May. These results suggest that blood epinephrine concentration could be a good neuroendocrine marker of sportspeople's phagocytic response.     

A predictive model for freshwater bioassessment (Mondego River,Portugal)

We sampled macroinvertebrates at 75 locations in the Mondego river catchment, Central Portugal, and developed a predictive model for water quality assessment of this basin, based on the Reference Condition Approach. Sampling was done from June to September 2001. Fifty-five sites were identified as “Reference sites” and 20 sites were used as “Test sites” to test the model. At each site we also measured 40 habitat variables to characterize water physics and chemistry, habitat type, land use, stream hydrology and geographic location. Macroinvertebrates were generally identified to species or genus level; a total of 207 taxa were found. By Unweighted Pair Group Method with Arithmetic mean (UPGMA) clustering and analysis of species contribution to similarities percentage (SIMPER), two groups of reference sites were established. Using Discriminant Analysis (stepwise forward), four variables correctly predicted 78% of the reference sites to the appropriate group: stream order, pool quality, substrate quality and current velocity. Test sites’ environmental quality was established from their relative distance to reference sites, in MDS ordination space, using a series of bands (BEAST methodology). The model performed well at upstream sites, but at downstream sites it was compromised by the lack of reference sites. As with the English RIVPACS predictive model, the Mondego model should be continually improved with the addition of new reference sites. The adaptation of the Mondego model methodology to the Water Framework Directive is possible and would consist mainly of the integration of the WFD typology and increasing the number of ellipses that define quality bands. Handling editor: K. Martens     

Interaction of the organic anion 1-aniline 8-naphthalene sulfonate (ANS) with isolated rat hepatocytes

The interaction of ANS with rat hepatocytes in time was studied by fluorescence spectroscopy. The intercept of the first linear portion of the time curve of interaction showed a positive value over all the ANS concentration range employed. This value was maintained after cellular disruption by homogenization. It was affected by ionic strength, pH, and divalent cation in the incubation medium, all conditions affecting the cellular surface. These data suggest that this phenomenon might be a binding of the compound to the hepatocytes surface. Due to the time constant and its disappearance after cellular disruption the other slower component of the curve seems to correspond to a process of translocation across the membrane.     

Heat stress in the presence of low RNA polymerase activity increases chromosome copy number of Escherichia coli

Summary A temperature shift-up accompanied by a reduction in RNA polymerase activity in Escherichia coli causes an increased rate of initiation leading to a 1.7- to 2.2-fold increase in chromosome copy number. A temperature shift-up without a reduction in polymerase activity induces only a transient non-scheduled initiation of chromosome replication caused by heat shock with no detectable effect on chromosome copy number.     

The spread of somatosensory-evoked potentials within the nervous system

Four thalamic and cortical recordings were carried out in 5 patients. The thalamic-evoked potentials were typical and revealed a triphasic complex, but their latencies showed a relatively high standard deviation. They could be divided into two groups according to their latencies, both of which had low SD. These data suggested that there could be two types of latency of thalamic SEP, because the 4 patients' body sizes were very similar. More detailed surface, cortical and depth recordings are needed to resolve these questions.