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Biomedical subjects

S Young

Publications and source records attributed to S Young.

At least 217 records · Page 12Linked to original sources
PubMed1989

Bilateral chorioretinitis, centripetal optic neuritis, and encephalitis in a llama.

Blindness characterized by dilated, unresponsive pupils and ophthalmoscopic evidence of optic nerve atrophy and retinal degeneration developed in a 5-year-old llama. Lesions were not progressive during 2 months of observation. The llama was euthanatized and necropsied. Histopathologic findings included chorioretinitis, optic neuritis, and encephalitis characterized by mononuclear perivascular infiltration. Attempts to prove an infectious cause were unsuccessful.

Animals↗
PubMed1989

Blindness and sexual dimorphism associated with vitamin A deficiency in feedlot cattle.

Clinical, ophthalmoscopic, and histopathologic findings of vitamin A deficiency in a group of 535 feedlot cattle are described. Liver vitamin A content and results of histologic examination of ocular and osseous (optic canal) tissue confirmed the diagnosis. Blindness was the only clinical sign observed. Even though the steers and heifers in this feedlot were approximately the same age and were fed the same ration for an equal period, none of the heifers had overt clinical signs of hypovitaminosis A. Production of vitamin A by the bovine corpus luteum may account for the sexual dimorphism observed in vitamin A-deficient cattle.

Animals↗
PubMed1989

Macrophage responsiveness to light therapy.

Macrophages are a source of many important mediators of wound repair. It was the purpose of this study to see if light could stimulate the release of these mediators. In this study an established macrophage-like cell line (U-937) was used. The cells were exposed in culture to the following wavelengths of light: 660 nm, 820 nm, 870 nm, and 880 nm. The 820-nm source was coherent and polarised, and the others were non-coherent. Twelve hours after exposure the macrophage supernatant was removed and placed on 3T3 fibroblast cultures. Fibroblast proliferation was assessed over a 5-day period. The results showed that 660-nm, 820-nm, and 870-nm wavelengths encouraged the macrophages to release factors that stimulated fibroblast proliferation above the control levels, whereas the 880-nm wavelength either inhibited the release of these factors or encouraged the release of some inhibitory factors of fibroblast proliferation. These results suggest that light at certain wavelengths may be a useful therapeutic agent by providing a means of either stimulating or inhibiting fibroblast proliferation where necessary. At certain wavelengths coherence is not essential.

Animals↗
PubMed1989

Multisite recording of brain field potentials and unit activity in freely moving rats.

A technique has been developed to record from 16 different brain sites of the freely moving rat using subminiature MOSFET preamplifiers. The high input impedance, small size, durability and light weight of the amplifiers and connecting cable allows high quality multisite recording of field potentials and unit activity. In addition, a movable headstage for positioning multiple microelectrodes is described. The compact recording system permits one to construct neocortical EEG maps, instant depth profiles of evoked and spontaneous field data, and to study neuronal synchrony of distant cell populations.

Action Potentials↗
PubMed1989

Comparison of serum beta-2-microglobulin levels in patients with symptoms of allergic rhinitis and elevated modified RAST scores vs. a control population.

Forty-four subjects, having clinical histories consistent with allergic rhinitis with modified RAST score(s) of two or more for at least one of five locally prevalent aeroantigens, were compared with 48 control subjects with modified RAST scores of zero for all given aeroallergens. There was no significant difference between these two groups in mean levels of serum beta-2-microglobulin (Student's t, p greater than 0.05).

Adult↗
PubMed1989

Spinal cord compression due to thoracic disc herniation: results of microsurgical posterolateral costotransversectomy.

Fifteen consecutive patients with thoracic disc herniation treated by posterolateral microsurgical costotransversectomy are described. With appropriate modifications to the standard technique, costotransversectomy was found to be a suitable approach even for calcified central discs, and discs which had eroded intradurally. All patients had evidence of spinal cord compression preoperatively with varying degrees of leg weakness. The results of surgery are discussed. Ten patients who were disabled but ambulant showed marked improvement in symptoms and signs. Of the remaining five, all of whom were severely disabled and nonambulant preoperatively, four demonstrated significant improvement. Most patients mobilised rapidly, 13 being able to walk unaided within 24 hours. One patient developed an intrathoracic meningocoele postoperatively, which resolved after multiple percutaneous aspirations. Otherwise there were no serious pulmonary complications. We believe that costotransversectomy is the approach of choice for central as well as centrolateral and lateral thoracic disc herniations.

Adult↗
PubMed1988

Non-mydriatic Polaroid photography in screening for diabetic retinopathy: evaluation in a clinical setting.

Because of fears that Polaroid colour prints produced with a non-mydriatic fundus camera may not detect important sight threatening lesions in diabetes a study was conducted comparing retinal images obtained on Polaroid prints taken in "field" conditions with those on 35 mm transparencies and fluorescein angiograms. Almost one in five (22/127) Polaroid prints could not be assessed owing to poor quality compared with 3 (2.4%) 35 mm transparencies and 2 (1.6%) fluorescein angiograms. The pick up rate of microaneurysms, haemorrhages, and hard and soft (cotton wool spots) exudates was equivalent for Polaroid prints and 35 mm transparencies of equivalent quality. In two cases with disc new vessels, however, these were not seen on the Polaroid prints. The widespread use of Polaroid colour prints obtained with a non-mydriatic camera without the necessary operative and interpretive skills further limits the usefulness of the technique.

Diabetic Retinopathy↗
PubMed1988

A monoclonal antibody recognising the site of limited proteolysis of protein kinase C. Inhibition of down-regulation in vivo.

A monoclonal antibody to protein kinase C is described that recognises the site of limited proteolysis on the native enzyme. Binding of the antibody to the purified kinase in vitro blocks partial proteolysis by trypsin, and introduction of the Fab fragment into a rodent glioma cell line inhibits phorbol-ester-induced down-regulation of the kinase. These observations are discussed in the context of the domain structure of protein kinase C and the agonist-induced proteolysis of the kinase in vivo.

Animals↗
PubMed1988

Isolation of a cDNA clone from the B-G subregion of the chicken histocompatibility (B) complex.

The B-G antigens are highly polymorphic antigens encoded by genes located within the major histocompatibility complex (MHC) of the chicken, the B system. The B-G antigens of the chicken MHC are found only on erythrocytes and correspond to neither MHC class I nor class II antigens. Several clones were selected from a lambda gt11 erythroid cell expression library by means of rabbit antisera prepared against a purified, denatured B-G antigen. One clone chosen for further study, lambda bg28, was confirmed as a B-G subregion cDNA clone by the results obtained through using it as a nucleic acid hybridization probe. In Northern hybridizations lambda bg28 anneals specifically with erythroid cell mRNA. In Southern blot analyses the lambda bg28 clone could be assigned to the B system-bearing microchromosome of the chicken karyotype on the basis of its hybridization to DNA from birds disomic, trisomic, and tetrasomic for this microchromosome. The cDNA clone was further mapped to the B-G subregion on the basis of its pattern of hybridization with DNA from birds of known B region recombinant haplotypes. Southern blot analyses of the hybridization of lambda bg28 with genomic DNA from birds of known haplotypes strongly suggest that the B-G antigens are encoded by a highly polymorphic multigene family.

Animals↗
PubMed1988

Low-dose sufentanil as a supplement to halothane/N2O anaesthesia in infants and children.

Sufentanil as a supplement to halothane/N2O anaesthesia was evaluated in 32 unpremedicated infants and children age 6 months to 9 yr undergoing elective orthopaedic surgery. Patients were randomly assigned in a double-blind manner to receive one of four intravenous supplements: placebo, sufentanil 0.5, 1.0 or 1.5 micrograms.kg-1. Systolic arterial pressure (SAP), heart rate (HR) and end-tidal halothane concentration were recorded before and after induction, supplement administration, tracheal intubation, incision and every 15 min during the procedure. Venous catecholamine samples were obtained before and after incision. A pain score was assigned to the patients in the postanaesthesia care unit (PACU). Sufentanil at all three doses prevented increases in SAP and HR with intubation and incision, provided superior pain relief in the PACU and did not prolong wake-up time. Sufentanil 1.0 and 1.5 micrograms.kg-1 allowed for a reduction in the halothane requirements. Sufentanil 1.5 micrograms.kg-1 was associated with lower catecholamine levels than in the placebo group following incision. Sufentanil supplementation at 1.0 and 1.5 micrograms.kg-1 was associated with bradycardia and/or hypotension during induction and an increased incidence of vomiting during the first 24 hours postoperatively. One patient in the sufentanil 1.0 micrograms.kg-1 group whose surgical time was less than 45 min exhibited respiratory depression in the PACU requiring narcotic reversal. In conclusion, sufentanil 0.5 micrograms.kg-1 improved immediate postoperative pain relief and is acceptable as a supplement during halothane anasethesia in infants and children. The associated side effects of larger doses of sufentanil (1.0 and 1.5 micrograms.kg-1) make their use as a supplement to halothane anaesthesia unacceptable.

Analgesics, Opioid↗
PubMed1988

Comparison of efficiency of cardiologists and internists in managing patients with suspected myocardial chest pain.

The charts of 56 patients with chest pain who were admitted to the critical care units to rule out myocardial infarction were evaluated concurrently and retrospectively to compare the efficiency of cardiologists and internists. The number of unnecessary days used to rule out myocardial infarction, the number of unnecessary inhospital days used after ruling out myocardial infarction, the length of cardiac work-up, and the length of hospital stay were determined for 23 patients of cardiologists and 33 patients of internists. The cardiologists' patients had fewer unnecessary days after ruling out myocardial infarction (2.76 vs. 0.43 days, p less than .01) and a shorter length of hospital stay (5.15 vs. 2.91 days, p less than .02). We concluded that consideration should be given to increasing and refining the supplementary role of physician-experts to primary care physicians as one means of improved resource allocation.

Angina Pectoris↗
PubMed1988

Comparison of the effects of moist and dry conditions on dermal repair.

The effects on dermal repair of moist conditions, achieved by covering excised wounds with the adhesive polyurethane dressing OPSITE, and dry conditions, achieved by exposure to air through dry gauze dressings, were compared in full thickness excised wounds on porcine skin during the period from 1 to 21 d after injury. Quantitative studies were made of changes in the populations of neutrophils, macrophages, fibroblasts, and endothelial cells. The number of inflammatory phase cells (neutrophils and macrophages) decreased more rapidly under moist conditions than under dry conditions. There was also a more rapid increase in the number of proliferative phase cells (fibroblasts and endothelial cells) in the moist wounds; by 5 d after injury 66% of the cells of the granulation tissue of the moist wounds were of this type, compared with only 48% of the cells of equivalent areas of the dry wounds. By 21 d after injury the number of fibroblasts in the granulation tissue of the moist wounds had fallen below that in the dry wounds, suggesting that progress from the proliferative into the remodelling phase of repair was more rapid in the moist wounds. It was concluded that there was an acceleration of the inflammatory and proliferative phases of dermal repair in wounds healing under moist conditions when compared with those healing under dry conditions.

Air↗
PubMed1988

Relief of lumbar canal stenosis using multilevel subarticular fenestrations as an alternative to wide laminectomy: preliminary report.

We describe an operative approach to lumbar canal stenosis which, unlike laminectomy, takes into account the segmental pathology of the disease. At each level involved, a bilateral subarticular fenestration is performed under high magnification. The medial third of each facet joint is first removed with an air-powered drill; then the remaining two-thirds of the joint is undercut with the drill to allow a generous fenestration in the thickened ligamentum flavum and adjacent laminae. All tissue responsible for neural compression is removed, but the spinous processes, interspinous ligaments, and much of the facet joints and laminae are preserved. Spinal stability is maintained and, because tissue disruption is minimized, postoperative discomfort is usually reduced, promoting early mobility and reduced hospital stay. The operation is described in detail, and the results of operation in 32 patients are assessed. The follow-up periods now range from 17 to 58 months. Of 23 patients who presented with neurogenic claudication, 14 (61%) obtained complete relief and 7 (30%) improved significantly. The mean hospital stay was 9 days (range, 4 to 17 days).

Adult↗
PubMed1988

The St Georg sledge for unicompartmental replacement of the knee. A prospective study of 115 cases.

Since 1974, we have made a prospective study in Bristol of the results of unicompartmental knee replacement using the St Georg sledge prosthesis. A total of 115 knees in 100 patients have been followed up for 2 to 12 years (mean, 4 years 9 months). Results have assessed both by the Bristol knee score and by survivorship studies on the total series of 138 knees. Results were excellent or good in 86% and fair or poor in 14%. The survivorship study (based on a definition of failure which included significant pain or a dissatisfied patient or the need for revision) showed a cumulative success rate of 76.4% at six years, with no further failures after that time. Seven knees have been revised, in most cases for deterioration of the contralateral compartment. The operation is recommended as a satisfactory and durable form of treatment for osteoarthritis affecting a single tibiofemoral compartment.

Adult↗