Electron spin resonance and photoacoustic spectroscopy of a-CSi:H and a-SiGe:H alloys

Results are reported of combined optical and photoacoustic spectroscopy measurements and electron spin resonance measurements (ESR) in binary alloys:a-Si_xGe_1-x:H at different x values and a-CSi:H at different deposition temperatures. Experimental values of optical data and Urbach tails agree very well with a model which takes into account the band gap fluctuations. The densities of spins as obtained by ESR measurements are correlated with the values of integrated absorption in the low energy range.     

Risk factors and prevalence of antibodies against hepatitis A virus (HAV) in children from day-care centers, in Goiania, Brazil

A comparative interim analysis was performed of clinical parameters, computed tomographic (CT) scan results and technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (SPET) findings obtained within 12 h of acute supratentorial ischaemic infarction. First, the applicability for SPET semiquantification in this study of the "method of Mountz", simultaneously accounting for extent and degrees of hypoperfusion by expressing deficits as millilitre of zero perfusion, was considered. Next, the relative contributions of perfusion SPET and CT scan in the acute stage of ischaemic infarction were compared in 27 patients (mean age 68.8 years). Finally, the correlation of SPET lesions with clinical parameters at onset was evaluated. The method of Mountz represents a workable, accurate virtual parameter, with the assumption that the contralateral brain region remains uninvolved. Interobserver reproducibility in 12 SPET studies, with lesions varying between 6 and 369 cc, showed a correlation coefficient r of 0.99. In practice, because of inconstant distribution of activities in the brain, the method can only be applied slice by slice and not on the total global volume. While the mean delay since the onset of symptomatology was approximately 7 h for both SPET and CT scan, SPET showed lesions concordant with the clinical neurological findings in 100% and CT scan in only 48%. One could hypothesize that SPET examinations performed later would show larger functional defects, because of the development of additional functional changes secondary to biochemical alterations. However, in this regard no statistically significant differences were found between two subproups, taking the median of delay before SPET examination as cut-off.(ABSTRACT TRUNCATED AT 250 WORDS)     

Percutaneous varicocele occlusion: long-term follow-up

We investigated the mechanism of resistance in murine L1210 leukaemia cells selected after treatment with FCE 23762 methoxymorpholinyl doxorubicin: (MMRDX), a methoxymorpholinyl derivative of doxorubicin active in vitro and in vivo on multidrug-resistant (mdr) cells, currently undergoing phase I clinical trials. The resistant subline obtained after repeated in vitro treatments, L1210/MMRDX, is resistant in vitro and in vivo to all tested methoxymorpholinyl derivatives and to cyanomorpholinyl doxorubicin, but shows resistance to morpholinyl derivatives only in vivo or following their activation with rat S9-liver fractions in vitro. L1210/MMRDX cells are sensitive to classic mdr- and altered topoisomerase (AT)-mdr-associated drugs. These cells do not appear to overexpress the mdr1 gene, nor do they exhibit impaired intracellular drug accumulation and efflux or altered levels of glutathione and glutathione S-transferase. The extent of DNA single-strand break formation and, after microsomal activation, of DNA interstrand cross-links after treatment with MMRDX was similar in the parent and the resistant subline. The mechanism of resistance in L1210/MMRDX cells remains to be identified but may prove a novel one, highly specific for this class of mdr-active anthracyclines.     

Interactions of amygdala lesions with effects of pilocarpine and d-amphetamine on mouse killing, feeding, and drinking in rats

Repeated injections of 7.5 mg/kg pilocarpine induced mouse killing in both amygdala-lesioned and sham-operated rats, but more injections were required in the lesioned animals. Killing was evoked least readily in rats that showed substantial weight loss after surgery and that had damage to more medial regions of the amygdala. d-Amphetamine (.75, 1.50, or 3.00 mg/kg), administered either before or after a killing test, inhibited pilocarpine-induced killing in both surgical groups. Amygdala lesions attenuated pilocarpine-facilitated drinking in sated animals but did not alter the inhibitory effects of either pilocarpine or d-amphetamine on feeding or drinking.