Functional topography of cat primary auditory cortex: response latencies

Minimum onset latency (Lmin) of single- and multiple-unit responses were mapped in the primary auditory cortex (AI) of barbiturate-anesthetized cats. Contralateral Lmin for multiple units was non-homogeneously distributed along the dorso-ventral/isofrequency axis of the AI. Responses with shorter latencies were more often located in the central, more sharply tuned region while longer latencies were more frequently encountered in the dorsal and ventral portions of the AI. For single units, a large scatter of Lmin values was found throughout the extent of the AI including cortical depth. The relationship between Lmin and previously reported spectral, intensity and temporal parameters was analyzed and revealed statistically significant correlations between minimum onset latency and the following response properties in some but not all studied animals: sharpness of tuning of a frequency response area 10 dB above threshold, broadband transient response, strongest response level, monotonicity of rate/level functions, dynamic range, and preferred frequency modulation sweep direction. This analysis suggests that Lmin is determined by several independent factors and that the prediction of Lmin based on relationships with other spectral and temporal response properties is inherently weak. The spatial distribution and the functional relationship between these response parameters may provide an important aspect of the time-based cortical representation of specific features in the animal's natural environment.     

Ultrasound‐activated Knoevenagel condensation of malononitrile with carbonylic compounds catalysed by alkaline‐doped saponites

α,β‐Unsaturated nitriles have been synthesized by Knoevenagel condensation of a carbonylic compound with malononitrile, assisted by sonochemical irradiation. Two alkaline‐promoted clays (Li⁺‐ and Cs⁺‐exchanged saponites) have been employed as catalysts. The influence of the carbonylic compound (benzaldehyde or cyclohexanone) and the use of a solvent on the catalytic activity have been studied. Remarkable increase in the conversion values has been found when the reaction is activated by ultrasound, as compared with the thermal activation. In this green, solvent‐free procedure, α,β‐unsaturated nitriles have been produced in very high yields (97%) when the Cs⁺‐saponite is used as catalyst. Copyright © 2004 Society of Chemical Industry     

Risk management in the hospital industry

The author provides an introduction to the risk management process in the hospital industry as well as explains some of the basic elements in a risk management program in such industry. The author also explains the factors to be evaluated in a risk management program.     

Relations between cardiac and vascular structure in patients with primary and secondary hypertension

BACKGROUND: Data on cardiac and vascular structure in secondary hypertension are generally scarce, and no data on the interrelations between cardiac mass and structural characteristics of the vessel wall, both in large and in small resistance arteries, are presently available. OBJECTIVES: The aim of this study was to investigate the relation between structural changes in subcutaneous small arteries, left ventricular mass and wall thickness of the common carotid artery in patients with primary and secondary hypertension. METHODS: Seventy-four subjects were included in the study: 11 patients with pheochromocytoma, 14 with primary aldosteronism (PA), 19 with renovascular hypertension (RVH), 18 with essential hypertension (EH) and 12 normotensive (NT) control subjects. All subjects were submitted to a biopsy of subcutaneous fat. Morphologic characteristics of subcutaneous small resistance arteries (relaxed diameter <300 microm) were directly evaluated using a micromyographic technique. All subjects were submitted to calculation of left ventricular mass index (LVMI) and common carotid artery intima-media thickness (CCIMT), using ultrasound technique. RESULTS: The correlation coefficients between the media to lumen ratio in subcutaneous small arteries (M/L) and LVMI or between M/L and CCIMT were closer in RVH than in pheochromocytoma, EH or NT; in PA the correlation coefficients were slightly less close than those in RVH. An excess prevalence of carotid plaques in RVH was observed. CONCLUSIONS: A close relation between small resistance artery morphology and cardiac or carotid artery structure may be observed in those hypertensive patients in whom the renin-angiotensin-aldosterone system is activated. In constrast, in NT, EH and pheochromocytoma no significant correlation between M/L and LVMI or CCIMT was observed.     

Hydrogen peroxide induced impairment of post-ischemic ventricular function is prevented by the sodium-hydrogen exchange inhibitor HOE 642 (cariporide)

Using highly degenerate, serine-protease-specific PCR primers on a midgut-specific cDNA library it was estimated that a minimum of 24 independent serine proteases were expressed in the midgut of Stomoxys calcitrans. The relative abundance of these 24 independent serine proteases has been estimated by restriction analysis of PCR products, showing that 69% fall into six almost equally abundant groups. Two highly abundant serine protease cDNAs (Ssp1 and Ssp2) were isolated and sequenced. They encode preproenzymes of 272 amino acids (Mr 28521) and 255 amino acids (Mr 27097) with putative signal peptides of 17 amino acids and 16 amino acids, putative activation peptides of 15 amino acids and 10 amino acids and mature enzymes of 239 amino acids (Mr 25322; pI 4.89) and 228 amino acids (Mr 24182; pI 7.59), respectively. Both deduced amino acid sequences contain the Asp/His/Ser catalytic triad and the highly conserved sequences surrounding it. Ssp2 also has the aspartate and two glycine residues in the specificity pocket, marking this as a typical trypsin. The positioning of the residues in the specificity pocket of Sspl is unusual; aspartate and glycine residues are present, which is typical of trypsin, but both are separated from surrounding conserved residues by additional amino acids; the second glycine found in the specificity pocket of trypsin is replaced by a serine, which is typical of chymotrypsin. Although a serine protease, the precise substrate specificity of Sspl remains to be determined. Northern analysis shows that both serine proteases are expressed constitutively with only a 20% change in the levels of expression of Ssp1 and Ssp2 through the digestive cycle, and that expression occurs predominantly in the opaque region of the midgut, the region responsible for secretion of digestive enzymes.