Drug distribution in spinal cord during administration with spinal loop dialysis probes in anaesthetized rats

The present investigation aimed to study two methodological concerns of an experimental model, where a spinal loop dialysis probe is used for administration of substances to the spinal cord and sampling of neurotransmitters by microdialysis from the same area of anaesthetized rats. [(3)H]Epibatidine in concentrations of 1, 10 and 100 nM was dissolved in Ringer's solution and administered through the dialysis membrane into the dorsal region of the cervical spinal cord. First, the outflow of [(3)H]epibatidine from the probe into the spinal cord was examined with respect to different concentrations and changes over time. Then, the distribution of the different [(3)H]epibatidine concentrations along the spinal cord was studied. It was found that the percentage of [(3)H]epibatidine entering the spinal cord did not differ between different administered concentrations after a stabilization period of 60 min. The administered [(3)H]epibatidine was found to be distributed to the area closest to the dialysis probe and not dispersed along the spinal cord, and the distribution was equal for all concentrations. The data presented in this investigation provide information, which is important for interpretation of data from intraspinal administration of substances through the spinal loop dialysis probe.     

Population structure in the Western Pyrenees: social class,migration and the frequency of consanguineous marriage, 1850 to 1910

The effects of social class on migration distances and on the frequency of consanguineous marriages in Errazu, a Pyrenean village in Navarre, Spain, have been studied using data from parish records of baptisms and marriages, 1850–1910, and the census data for the year 1897.

Migration distances are greater for tenants than for land-owners. Mean marital distances are not significantly different for the two social classes, but the movement of tenant families during married life results in significantly different parent-offspring distances for the two classes, at the 0·001 level for fathers and at the 0·002 level for mothers, by a t-test.

Consanguineous marriages, up to and including third cousin marriages, are more frequent among land-owners (16·3 per cent) than among tenants (3·7 per cent). These frequencies are consistent with estimates based on the demographic characteristics of the population. Some implications of these results are discussed with reference to the findings of communities elsewhere in Europe and studies of communities in Japan. The implications of variation in the social class composition of populations with population density, for pedigree inbreeding values, are also considered.     

Determination of the solute removal index for urea by using a partial spent dialysate collection method

In 22 hemodialysis patients, during a dialysis session, the solute removal index (SRI) for urea obtained from the use of a partial spent dialysate collection method was compared with that derived from the use of a total spent dialysate collection technique. The partial spent dialysate collection method was used to harvest a small representative sample of the total spent dialysate. The volumes of spent dialysate collected by the partial and the total spent dialysate collection methods were 1.7 +/- 0.4 L and 129.6 +/- 15.3 L, respectively. The total amount of urea nitrogen removed by dialysis as estimated by the partial spent dialysate collection method was similar to that determined by the total spent dialysate collection approach. As a result, the SRI value for urea obtained by the partial spent dialysate collection method (namely, 63% +/- 8%) correlated very well (r = 0.95, P < 0.001) with that derived by the total spent dialysate collection technique (namely, 62% +/- 8%). Our data suggest that it is feasible to use a simple partial spent dialysate collection method to obtain SRI results in patients treated with hemodialysis.     

Anxious and depressive disorders and their comorbidity: effect on central nervous system noradrenergic function.

BACKGROUND: Although comorbidity of anxiety with depression is common, investigations of physiologic abnormalities related specifically to comorbidity are rare. This study examined relationships of DSM-IV-defined depression, anxiety, and their comorbidity to noradrenergic function measured by blunting of the growth hormone (GH) response to the alpha2 adrenoreceptor agonist (and imidazoline receptor agent) clonidine and by blood pressure and symptom responses. METHODS: Fifteen subjects with pure social anxiety or panic disorder, 15 with pure major depression, and 18 with both depression and anxiety were compared with healthy control subjects matched for age and gender. Other factors known to affect GH (weight, menstrual status, prior antidepressant, or other drug exposure) were controlled. RESULTS: Anxiety produced GH blunting, but depression was associated with normal GH responses. The comorbid state did not affect results beyond the impact of anxiety. Preclonidine stress-related GH elevations were observed, to the greatest degree in anxious subjects. Relevant symptom, but not blood pressure, changes were significantly associated with blunting. CONCLUSIONS: With use of pure depression and anxiety groups and careful control of other factors known to affect GH, these results demonstrate central nervous system noradrenergic dysfunction in anxiety disorders. In contrast to less rigorously controlled studies, noradrenergic function in depression was normal.