d-serine regulation of the timing and architecture of the inspiratory burst in neonatal mice.

d-serine, released from mouse medullary astrocytes in response to increased CO2 levels, boosts the respiratory frequency to adapt breathing to physiological demands. We analyzed in mouse neonates, the influence of d-serine upon inspiratory/expiratory durations and the architecture of the inspiratory burst, assessed by pwelch's power spectrum density (PSD) and continuous wavelet transform (CWT) analyses. Suction electrode recordings were performed in slices from the ventral respiratory column (VRC), site of generation of the respiratory rhythm, and in brainstem-spinal cord (en bloc) preparations, from the C5 ventral roots, containing phrenic fibers that in vivo innervate and drive the diaphragm, the main inspiratory muscle. In en bloc and slice preparations, d-serine (100 µM) reduced the expiratory, but not the inspiratory duration, and increased the frequency and the regularity of the respiratory rhythm. In en bloc preparations, d-serine (100 µM) also increased slightly the amplitude of the integrated inspiratory burst and the area under the curve of the integrated inspiratory burst, suggesting a change in the recruitment or the firing pattern of neurons within the burst. Time-frequency analyses revealed that d-serine changed the burst architecture of phrenic roots, widening their frequency spectrum and shifting the position of the core of firing frequencies towards the onset of the inspiratory burst. At the VRC, no clear d-serine induced changes in the frequency-time domain could be established. Our results show that d-serine not only regulates the timing of the respiratory cycle, but also the recruitment strategy of phrenic motoneurons within the inspiratory burst.

Multispecies high-energy emitter for CO2, CH4, and H2O monitoring in the 2 µm range.

We demonstrate the first emitter, based on a single optical source device, capable of addressing three species of interest (CO2, CH4, and H2O) for differential absorption Lidar remote sensing of atmospheric greenhouse gases from space in the 2 µm region. It is based on an amplified nested cavity optical parametric oscillator. The single frequency source shows a total conversion efficiency of 37% and covers the 2.05-2.3 µm range.

In vitro conditions for the study of the in vivo performance of sustained-release theophylline matrix tablets administered in fasted conditions and with a high-fat diet.

Dissolution profiles of theophylline (TP) from three types of sustained-release (SR) matrix tablets (plastic [PL], lipid [LP], and hydrophilic [HP]) in different dissolution media, with and without enzymes, were established. Also investigated was the influence of a treatment of the tablets with peanut oil prior to the dissolution test. The in vivo behavior of the tablets under the fasted state and with the concomitant administration with a high-fat diet was previously evaluated; the diet produced changes in the absorption profiles for the three matrix tablets in comparison with fasted administration. Level A correlations were obtained between cumulative percentage dissolved (CPD) and cumulative percentage absorbed (CPA). For the fasted condition, better correlations were obtained with water as the dissolution medium for the HP and LP matrix; for PL matrix, the best correlation was obtained with a medium with gradual change of pH. The pretreatment with peanut oil showed better correlations for the fed state.

A prospective one-year study evaluating the clinical outcome of recipients of living donor kidneys treated with cyclosporin and azathioprine.

Thirty recipients of living related donor kidneys treated either with cyclosporin or azathioprine were evaluated clinically and functionally in a 1-year prospective study. Only the azathioprine group showed either accelerated or chronic rejection (one patient each). The azathioprine patients had higher rate of infectious episodes (P = 0.05), leukopenia (P = 0.003) and steroidal side-effects (P less than 0.007). During the early post-transplant period the renal functional performance was the same in both groups. Afterwards, however, the plasma creatinine was higher in the cyclosporin group (P less than 0.01). Mean arterial pressure remained similar throughout the study in both groups. The anaemia correction was similar in both groups but the haematocrit was greater in the cyclosporin-treated subjects (P less than 0.005).