Sucrose density differences of Chlamydia psittaci 6BC in relation to its host

Previous studies on Chlamydia psittaci 6BC propagated in different hosts have shown differences in cytotoxicity but no differences in the ultrastructure of the individual particles. It is shown here that the 6BC strain derived from yolk sac of infected chick embryo sedimented in sucrose gradients at lower densities than the 6BC strain derived from L-cells. Host-related modifications of lipid concentrations of the 6BC strains have been previously documented by others. It is thought that the phenomenon of host-induced modifications of physical properties of the agent might provide a new approach to the study of chlamydial pathogenicity.     

Lesions of swine lymph nodes as a diagnostic test to determine mycobacterial infection.

Decisions as to the disposition of swine carcasses with lesions attributable to a mycobacterial infection are based upon a lesion criterion which is used as a diagnostic test by federal meat inspectors. Using this criterion, a federal meat inspector classified 58 of 100 pigs as "passed for cooking" and the other 42 pigs passed. Of the 58 pigs passed for cooking and the 42 pigs passed, mycobacterial isolations were made from the lymph nodes of 33 and 15 of the animals, respectively. The lesion criterion as a diagnostic test has the following attributes: 70% sensitive; 53% specific; 23% index of performance; 57% positive accuracy; and 67% negative accuracy.     

Cross-arm triangular flaps for correction of adduction contracture of the first web space in the hand: case report.

We describe the use of two oppositely-based, triangular, cross-arm flaps for primary coverage of a new first web space, created by releasing an abduction contracture of the thumb.     

Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.     

The Drosophila homologue of the dystrophin gene - introns containing promoters are the major contributors to the large size of the gene

We show that the drosophila gene encoding the dystrophin-like protein (DLP) is as complex as the mammalian dystrophin gene. Three 5' promoters and three internal promoters regulate the expression of three full-length and three truncated products, respectively. The existence of this complex gene structure in such evolutionary remote organisms suggests that both types of products have diverse important functions. The promoters of both the DLP gene and the mammalian dystrophin gene are located in very large introns. These introns contribute significantly to the large size of the genes. The possible relevance of the conservation of the large size of introns containing promoters to the regulation of promoter activity is discussed.     

Structural basis of severe acute respiratory syndrome coronavirus ADP-ribose-1''-phosphate dephosphorylation by a conserved domain of nsP3

The crystal structure of a conserved domain of nonstructural protein 3 (nsP3) from severe acute respiratory syndrome coronavirus (SARS-CoV) has been solved by single-wavelength anomalous dispersion to 1.4 A resolution. The structure of this "X" domain, seen in many single-stranded RNA viruses, reveals a three-layered alpha/beta/alpha core with a macro-H2A-like fold. The putative active site is a solvent-exposed cleft that is conserved in its three structural homologs, yeast Ymx7, Archeoglobus fulgidus AF1521, and Er58 from E. coli. Its sequence is similar to yeast YBR022W (also known as Poa1P), a known phosphatase that acts on ADP-ribose-1'-phosphate (Appr-1'-p). The SARS nsP3 domain readily removes the 1' phosphate group from Appr-1'-p in in vitro assays, confirming its phosphatase activity. Sequence and structure comparison of all known macro-H2A domains combined with available functional data suggests that proteins of this superfamily form an emerging group of nucleotide phosphatases that dephosphorylate Appr-1'-p.     

SUPRACONDYLAR AMPUTATION IN THE AGED

Of 105 consecutive supracondylar amputations done at the San Diego County General Hospital during the five-year period, 1953-58, 88 were in patients more than 60 years of age. Occlusive arterial disease was the reason for operation in 85 of the 88 cases.Presenting complaints at the time of amputation were gangrene in 45 cases, pre-gangrene associated with severe pain in 34. Acute arterial occlusion as a cause of thigh amputation was infrequent.The average age of patients requiring thigh amputation from complications of arteriosclerosis obliterans was 78.3 years; for those with diabetic arteriosclerosis or embolism it was about seven and a half years less.Supracondylar amputation was considered the procedure of choice in the elderly debilitated patients with far-advanced occlusive diffuse arteriosclerosis, complicated by gangrene, ulcer and infection of the toes or feet. Sympathectomy and direct arterial operation if done early in the course of the disease may postpone or prevent subsequent amputation.The surgical mortality rate (first two weeks) for supracondylar amputation was 12.5 per cent. More than two-thirds of the deaths were due to bronchopneumonia.     

Nerve growth factor induces changes in (2'-5')oligo(A) synthetase and 2'-phosphodiesterase activities during differentiation of PC12 pheochromocytoma cells

Treatment of rat pheochromocytoma cell line PC12 with Vipera lebetina (snake) nerve growth factor (NGF) induces a rapid increase (from 5 to 25-fold) in the level of (2'-5')oligo(A) synthetase activity and a simultaneous decrease (from 2 to 5-fold) in the activity of 2'-5' A degrading enzymes--2'-phosphodiesterases (2'-PDE). These changes in the enzyme activities led to the significant increase in the intracellular concentration of 2'-5' A. We have found that the serum starvation of PC12 cells causes a 1.5 to 2.0-fold increase in the level of 2'-5' A-synthetase activity, but the activities of 2'-PDE and the intracellular concentration of 2'-5' A remain unaltered. These results show that NGF modulates the activity of (2'-5')oligo(A) enzymes and intracellular concentration of 2'-5' A during the neural differentiation of PC12 cells.