Pulmonary physiological and surfactant changes during injury and recovery from hyperoxia

The time course of lung injury and recovery from a sublethal exposure to 100% O2 was investigated in adult rabbits. Animals were exposed to 100% O2 for 64 h and then returned to room air for varying periods of time up to 200 h. By the end of the exposure period, the alveolar permeability to solute increased significantly, and biochemical analyses of bronchoalveolar lavages showed a 30% decline in phospholipid content and a threefold increase in protein levels. However, other parameters such as wet-to-dry lung weight ratios, blood gas values, and pressure-volume mechanics were not significantly different from control levels after 64 h of hyperoxia. Twenty-four hours postexposure, alveolar phospholipid levels had declined even further (51% of control), and mean protein levels in lavage increased to eight times control values. These lavages exhibited severely impaired dynamic surface activity at 37 degrees C and 100% humidity in an oscillating bubble apparatus. In addition, total lung capacity, lung compliance, and arterial O2 partial pressure declined greatly at this time. Between 12 and 48 h postexposure, animal mortality was 35%; the remaining animals survived, and physiological parameters returned to normal by 200 h postexposure. Bronchoalveolar lavages from the recovered animals contained protein levels equal to those of controls and phospholipid levels approximately twice those in control lavages. Lavage surface activity also returned to normal by the 200 h postexposure time point.     

Hormone-sensitive lipase is localized at synapses and is necessary for normal memory functioning in mice

Hormone-sensitive lipase (HSL) is mainly present in adipose tissue where it hydrolyzes diacylglycerol. Although expression of HSL has also been reported in the brain, its presence in different cellular compartments is uncertain, and its role in regulating brain lipid metabolism remains hitherto unexplored. We hypothesized that HSL might play a role in regulating the availability of bioactive lipids necessary for neuronal function and therefore investigated whether dampening HSL activity could lead to brain dysfunction. In mice, we found HSL protein and enzymatic activity throughout the brain, localized within neurons and enriched in synapses. HSL-null mice were then analyzed using a battery of behavioral tests. Relative to wild-type littermates, HSL-null mice showed impaired short-term and long-term memory, yet preserved exploratory behaviors. Molecular analysis of the cortex and hippocampus showed increased expression of genes involved in glucose utilization in the hippocampus, but not cortex, of HSL-null mice compared with controls. Furthermore, lipidomics analyses indicated an impact of HSL deletion on the profile of bioactive lipids, including a decrease in endocannabinoids and eicosanoids that are known to modulate neuronal activity, cerebral blood flow, and inflammation processes. Accordingly, mild increases in the expression of proinflammatory cytokines in HSL mice compared with littermates were suggestive of low-grade inflammation. We conclude that HSL has a homeostatic role in maintaining pools of lipids required for normal brain function. It remains to be tested, however, whether the recruitment of HSL for the synthesis of these lipids occurs during increased neuronal activity or whether HSL participates in neuroinflammatory responses.     

Neo-Timm and selenium stainable glial cells of the rat telencephalon

Summary The presence of endogenous growth-related polypeptide hormones, such as growth hormone (GH), somatomadin-C/insulin-like growth factor-1 (SM-C/IGF-1), prolactin (PRL) and Mullerian inhibiting substance (MIS) on chick embryonic tissues have been detected by electron microscopic (EM) immunocytochemistry. Antiserum against GH, anti-SM-C/IGF-1, anti-PRL and anti-MIS were used respectively as primary antibodies for immunolabeling probes by peroxidase (PO) and avidin-biotin complex (ABC)-gold ligands. Cross-reaction studies by ELISA showed negative or weak antigen-antibody interactions. Chick embryos, gonads, and Mullerian ducts (Mds) of various ages were fixed in 2.5% glutaraldehyde for 30 min. Washes in phosphate buffer were administered between each of the following incubations: (i) 2% BSA; (ii) primary antibody; (iii) biotinylated or PO-conjugated secondary antibody; (iv) avidin conjugated with gold particles. SM-C/IGF-1 bindings were negative on 1d embryonic disc, heavily stained on 2d endoderm. However, the GH bindings were found on the embryonic layers of 1d and 2d embryos, and increasing on the luminal epithelial cells of Mds during development. PRL was found in parallel with GH, but in less amount. The 10d Mds were double labeled with anti-SM-C/IGF-1-gold and anti-MIS-PO (MIS-PO), and the results showed SM-C/IGF-I negative, but MIS-PO positive bindings. This study provides the first immunocytochemical evidences for: (i) The presence of GH, SM-C/IGF-1, PRL and MIS bindings on chick embryonic tissues, and further supports their potential role as growth mediators during embryonic development. (ii) The amount of GH and MIS bindings were found correspondingly to their physiological status of Md growth or regression. (iii) MIS is secreted by the embryonic gonads.     

Ultrasonically-guided Liver Biopsy

A method is described of fine-needle aspiration biopsy of liver metastases under direct guidance by ultrasonic scanning. Comparing the results with this technique and those with liver biopsy by Menghini''s method in 18 cases, we found that it was more accurate than the usual blind method.