Fluoroscopic chest tube insertion and patient care

Catheters and chest tubes may be placed under fluoroscopic control to reduce pleural effusions. This procedure has been adopted as a routine procedure at the UCLA School of Medicine in Los Angeles, California to improve patient care. This technique was modified for the placement of large chest tubes, which can be placed by a radiologist without multiple attempts or complications. Our experience with 2234 patients who underwent this procedure between 1977 and 1990 is described.     

Progressive neuropathologic lesions in vitamin E-deficient rhesus monkeys

A consistent group of progressive central and peripheral nervous system lesions developed in seven rhesus monkeys maintained on a vitamin E-deficient diet for 30 to 33 months. These lesions were absent from vitamin E-supplemented monkeys. The principal neuropathologic alteration was loss of sensory axons in the posterior columns, sensory roots, and peripheral nerves. Morphologic and morphometric studies indicated that the distal segments of the axons were affected most severely and large-caliber myelinated fibers are selectively involved. Swollen, dystrophic axons (spheroids) occurred infrequently. Degeneration and phagocytosis of small numbers of neuronal perikarya were observed in the dorsal root ganglia and the anterior horns. The number of affected neurons was not proportional to the number of affected axons. Accumulation of lipopigment was evident in neuronal perikarya and CNS endothelial cells. The nervous system lesion were usually accompanied by a chronic necrotizing myopathy. The neuropathologic lesions in vitamin E-deficient monkeys are compared with those in vitamin E-deficient rats and in humans with low serum vitamin E concentrations. A similar type of sensory axonopathy is associated with chronic deficiency of vitamin E in these three species.     

Time-dependent changes in the response of cartilage to static compression suggest interstitial pH is not the only signaling mechanism

The goal of the present study was to reexamine the role of interstitial pH in regulating the biosynthetic rate in cartilage tissue by addressing two research questions: (a) Do small, short-term changes in interstitial pH, induced independently by two different mechanisms (namely, by controlling the pH of the medium or by mechanical compression), result in biosynthetic rates commensurate with those expected from the "natural" relationship between interstitial pH and biosynthesis? and (b) Are the effects of changes in the pH of the medium or in compression the same for short-term (14-hour) and long-term (60-hour) exposures? Biosynthetic rates were estimated from incorporation of sulfate and proline into explants of bovine epiphyseal cartilage during the final 14 hours of culture. These rates decreased with decreasing pH of the medium, with increasing compression, and with decreasing native glycosaminoglycan content; or, expressed in terms of interstitial pH, acidification induced by compression or by lowering the pH of the medium resulted in a decreased biosynthetic rate, whereas interstitial acidification effected by increasing glycosaminoglycan content enhanced it. When the time for which tissue was exposed to changes in the pH of the medium was increased from 14 to 60 hours, the relationship between the biosynthetic rate and the pH remained constant whereas the relationship between the biosynthetic rate and compression was reversed. These data suggest that the transduction mechanisms underlying the response to pH of the medium and compression differ and that some adaptation or stimulation by modest levels of compression can occur with longer exposures. Interstitial pH is not the sole determinant of biosynthesis, and it cannot really account for the long-term response of cartilage tissue to static compression.     

Structural families in loops of homologous proteins: automatic classification, modelling and application to antibodies

Loop regions of polypeptide in homologous proteins may be classified into structural families. A method is described by which this classification may be performed automatically and "key residue" templates, which may be responsible for the loop adopting a given conformation, are defined. The technique has been applied to the hypervariable loops of antibodies and the results are compared with the previous definition of canonical classes. We have extended these definitions and provide complete sets of structurally determining residues (SDRs) for the observed clusters including the first set of key residues for seven-residue CDR-H3 loops.     

Skeletal muscle metabolism in two Pavulon treated tetanus patients

In two patients with severe tetanus the skeletal muscle metabolism was studied. Muscle biopsies were taken 4-6 weeks after the development of tetanus. The patients were treated during this time with a neuromuscular blocking agent. In one of the patients a biopsy was also taken before treatment, 2 days after the first symptoms of the disease. Enzyme activities representative for glycogen synthesis, glycogen greakdown, glycolysis, fatty acid beta-oxidation and respiratory chain, and fluxes of glucose, palmitate and leusine in vitro, and the concentrations of glycogen, triglycerides, phospholipids, cholesterol, proteins and RNA were determined in the muscle tissue. The enzyme activities in the muscle tissue examined 2 days after the development of tetanus were close to normal, excep for decreased activities of phosphofructokinase and glycogen synthase. After 4-6 weeks of treatment the fluxes of glucose and palmitate and the corresponding enzyme activities were low in both patients. These findings are consistent with muscular inactivity. In contrast the activity of glucose-6-phosphate dehydrogenase, the incorporation rate of leucine-carbon into proteins and the RNA content were high, indicating a high protein synthesis as a probable manifestation of active repairative processes. It is concluded that the skeletal muscle metabolism in these patients was affected in a degenerative manner and that this effect was attributed more to the treatment than to the disease per se. Dynamic physical training under supervision is recommended for the period after the generalized spasms to overcome the "disuse" effects in the skeletal muscles.     

Platelet aggregation measured by the screen filtration pressure method in hypertensive patients

In this study platelet aggregation was measured by the screen filtration pressure method in 2 groups of hypertensives separated according to age. They were perfectly matched for levels of various "risk factors", with normotensive "controls". No significant difference in platelet aggregate filtration pressure (PAFP) was found between hypertensives and normotensives. Contrary to normotensive subjects, there was no significant increase in the PAFP values with age in the hypertensives. This might be due to the significantly higher blood urea values in the hypertensives as compared to the normotensives. An inverse relationship between blood urea concentration and PAFP values was in fact confirmed by in vivo and in vitro studies.