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Biomedical subjects

R W Jackson

Publications and source records attributed to R W Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1982

The results of partial arthroscopic meniscectomy in patients over 40 years of age.

The role of arthroscopic meniscectomy in middle-aged patients has not previously been evaluated. This paper reports on 73 knees in 68 patients aged over 40, all of whom were shown arthroscopically to have meniscal tears and who were felt to be suitable candidates for meniscectomy. Many of these patients had typical traumatic meniscal tears, and if no degenerative joint changes were present at the time of meniscectomy, 95 per cent of them had good or excellent results an average of two and a half years later. In those instances where degenerative joint changes were present, removal of the offending segment of torn meniscus produced 80 per cent good or excellent results over the same period of time. These facts seem important now that arthroscopy permits such precise diagnosis of meniscal tears and of joint degeneration.

Adult↗
PubMed1982

The pathologic medical shelf.

It is now recognized that a previously normal fold of synovium on the medial side of the knee (a medial patellar plica) may, as a result of trauma, become pathologically inflamed and/or fibrosed, producing symptoms that may be mistakenly diagnosed as a torn meniscus or chondromalacia patellae. Clinical awareness, aided by arthroscopy, can establish the diagnosis. The correct treatment is simple and, if instituted early before irreversible changes have occurred in the femoral condyle articular cartilage, is extremely effective.

Arthroscopy↗
PubMed1981

Cardio-respiratory fitness and muscular strength in the lower-limb disabled.

The International Year of the Disabled Person has focused increased attention upon the fitness status of the wheelchair-confined. Review of the world literature indicates that cardio-respiratory assessment has been based relatively equally upon forearm cycling or wheelchair ergometry; each of these techniques have particular advantages. The evaluation of muscular strength and endurance has received much less attention, in spite of the importance of these factors to the daily function of the lower-limb impaired. Also neglected in the past has been the psychological correlates of spinal cord trauma and their possible interaction with attitudes concerning physical activity. Fitness is often poor in the disabled, and everyday wheelchair propulsion does not seem to provide a sufficient stimulus for cardio-respiratory adaptation. Additional training in the form of forearm pedalling, exercises with weights or wheelchair sports may provide an effective means of improving cardio-respiratory fitness and muscle function. Indeed, research on disabled athletes has suggested that with persistent sports participation or fitness conditioning many wheelchair-confined individuals can make a relatively good physiological and psychological adaptation.

Hemodynamics↗
PubMed1979

2-(Aminomethyl)-2-decarboxyprostaglandin F2 alpha type analogs.

The 2-(aminomethyl)-2-decarboxy analogs of prostaglandin F2 alpha (PGF2 alpha), (15S)-15-methyl-PGF2 alpha, 16-phenoxy-omega-tetranor-PGF2 alpha and 16,16-dimethyl-PGF2 alpha were synthesized. The amino analogs closely resemble the parent PGF2 alpha compounds as antifertility agents in the hamster.

Abortifacient Agents↗
PubMed1978

Synthesis of thromboxane B2 metabolites.

This paper reports the synthesis of 11-dehydrothromboxane B2 methyl ester (II), 15-dehydrothromboxane B2 methyl ester (III), 15-dehydro-13, 14-dihydrothromboxane B2 (XII) and 2,3-dinorthromboxane B2 methyl ester (XV). These compounds, as their free acids, have been reported to be thromboxane metabolites.

Methods↗
PubMed1978

Activation of the alternative complement pathway by a streptococcal lipoteichoic acid.

A glycerol lipoteichoic acid antigen from Streptococcus pyogenes 1-RP41 was found by rabbit erythrocyte hemolytic assay to activate the alternative complement pathway in human sera. Over a narrow concentration range of the teichoic acid, complement consumption was dose dependent, whereas at higher concentrations of the acid complement consumption could not be detected.

Antigens, Bacterial↗
PubMed1977

Effects of phosphate supplementation on intact and fractured femora of rats: a biomechanical study.

The production of a better and stronger healing bone has attracted the interest of many investigators in the past. Numerous substances have been used to increase both the strength and the rate of production of fracture callus. Recently phosphate, administered orally, has been suggested for this purpose. A biomechanical study was conducted with rat femora and variable doses of phosphate in this regard. Phosphate was found to benefit osteomalacic bones but to have no effect on normal bones and a toxic effect in high concentrations.

Alkaline Phosphatase↗
PubMed1976

Comparison of luteolytic effectiveness of several prostaglandin analogs in heifers and relative binding affinity for bovine luteal prostaglandin binding sites.

The relative binding affinities for both the prostaglandin (PG)E1 and PGF2alpha specific bovine luteal binding sites were determined for five PGE and fourteen PGF derivatives and analogs. Relative binding affinity was determined in vitro using membranes prepared from bovine corpora luteal (CL) obtained from the slaughterhouse. The parent structure of the analog was a dominant feature in determining the affinity for the respective PG binding site. Luteolysis was determined in cattle following intramuscular injection of various doses of prostaglandin once between days 6 and 14 after estrus and measuring CL regression by ovarian palpation per rectum, interval between injection and return to estrus and duration of the subsequent estrous cycle. A dose which was luteolytic was established for each of eight PGF-type compounds, and a dose which was not luteolytic was also established. There appeared to be limited association between the relative affinity for the PGF2alpha specific site in vitro and the estimated luteolytic dose range of these PGF analogs when tested in cattle. Differences in in vivo luteolytic potency for the compounds tested could not be explained by differences in binding affinity. Differences in metabolism and absorption may also be important in the determination of in vivo potency.

Animals↗
PubMed1976

Effects of a streptococcal lipoteichoic acid on host responses in mice.

A teichoic acid (TA) extracted from Streptococcus pyogenes 1-RP41 was previously shown to be an immunosuppressant under certain conditions (Miller and Jackson, 1973). The TA has now been shown to be a lipoteichoic acid composed of 40% glycerol, 20% alanine, 13% phosphorus, and 8% glucose, with a variable content of fatty acids. Teh presence of the polyglycerol phosphate backbone and fatty acid was required for maximum immunosuppression of the primary immunoglobulin M response to sheep cells. A complex, nonlinear, time-dependent dosage relationship in suppression of the anti-sheep erythrocyte response in mice was observed. TA depressed the anamnestic response to sheep cells in the mouse and could affect this response whether administered before the primary antigen challenge or immediately before the secondary challenge. In distinct contrast, TA enhanced antibody production to Escherichia coli O55:B5 lipopolysaccharide when assessed by counting plaque-forming cells or measuring antilipopolysaccharide serum titers. The TA failed to stimulate a large uptake of [3H]TdR by murine spleen cells; however, it significantly enhanced the clearance of carbon by the reticuloendothelial system.

Animals↗
PubMed1976

Immunogenicity of a purified and carrier-complexed streptococcal lipoteichoic acid.

Solublie teichoic acid could not stimulate the formation of antibodies either as an aqueous solution or in an emulsion with Freund incomplete adjuvant. However, when given as precipitates with methylated bovine serum albumin, it stimulated strong anti-teichoic acid responses. High levels of anti-teichoic acid antibodies usually resulted in allergic symptoms upon secondary challenge either with immunogenic teichoic acid-methylated bovine albumin complexes or with non-immunogenic soluble teichoic acid. These symptoms suggested anaphylatic shock, but probably also included the formation of complement-consuming immune complexes.

Adjuvants, Immunologic↗
PubMed1975

Amniotic fluid phospholipids and fetal lung maturity. I. Assessment of various methods of determining lecithin and sphingomyelin.

The measurement of the lecithin/sphingomyelin ratio in amniotic fluid as an index of fetal lung maturity has been a controversial and much-discussed topic since the initial report of this procedure appeared in the literature in 1971. Our laboratory has investigated several methods of measuring phospholipid components of amniotic fluid and compared relative reproducibility and accuracy. Correlation of these phospholipid determinations with the clinical presence or absence and relative severity of neonatal respiratory distress syndrome forms the basis of this report. Our findings indicate that careful attention to the biochemical basis of this test results in the ability to predict with great accuracy developmental respiratory distress syndrome. This presentation describes our method of determining lecithin/sphingomyelin ratios in amniotic fluid, compares our results with other tests for determining fetal maturity, and assesses the value of this procedure in clinical situations.

Amniotic Fluid↗
PubMed1975

Synthesis of dl-4,5,6-trinor-3,7-inter-m-phenylene-3oxaprostaglandins including one which inhibits platelet aggregation.

The synthesis of dl-4,5,6-trinor-3,7-inter-m-phenylene-3-oxaprostaglandins of the E1 and F1alpha series from 6-endo-(1-heptenyl)-bicyclo[3:1:0]hexan-3-one (III), is described. Preliminary biological screening data for gerbil colon smooth muscle stimulation, rat blood pressure and substrate specificity toward 15-hydroxyprostaglandin dehydrogenase is presented. Platelet function studies, both in vitro and in vivo of dl-4,5,6-trinor-3,7-inter-m-phenylene-3-oxa-PGE1, methyl ester (VIII) are presented.

Adenosine Diphosphate↗