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Biomedical subjects

L Watson

Publications and source records attributed to L Watson.

At least 127 records · Page 7Linked to original sources
PubMed1985

Methodology of a cerebral palsy register. The Western Australian experience.

Population-based disease registers serve a variety of purposes and have proven their value in stimulating and facilitating epidemiological research and health planning. The methods used to establish and maintain the Western Australian Cerebral Palsy Register are described. Efforts to reduce diagnostic variation by regular interobserver study meetings with clinicians have been highly productive in addition to promoting awareness of the requirements of the register. The existence of perinatal data sets as denominators are essential to monitor trends, which in turn generate hypotheses that can be readily investigated with the case population and basic variables already identified. The costs of setting up and running an ongoing register are thus offset by its output and potential uses. These, as well as its limitations, are discussed.

Australia↗
PubMed1984

Living with AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Relationships between plants relevant to allergy.

This article gives background information on the taxonomic relationships between plants, for clinicians, patients and students of allergy. A list is provided of plants considered potentially allergenic either by inhalation of pollen or by ingestion of grain products. Distributions in Australia of plant species important in assessing pollen-related allergy, and the range of foodstuffs that contain cereal-grain protein, are also indicated. Particular emphasis is placed on the grasses because of their importance as producers of both grain and pollen.

Cross Reactions↗
PubMed1984

Life Saver: a complete team approach incorporated into a hospital-based program.

Both military and civilian settings have shown that a team approach through an excellent prehospital Emergency Medical Services system, an organized regional communication system, access to rapid air evacuation with a "complete" medical team on board, and dedicated trauma resources allows a critically ill or injured patient optimal chances for survival. The Life Saver airborne emergency service, operated by Carraway Methodist Medical Center in Birmingham, Alabama, is a "complete team" concept with a well trained emergency physician and a critical care flight nurse aboard every flight. The physician upgrades the level of care at the scene of an accident, lessens the referring physician's anxiety, maintains an intensive care unit environment during transport and intervenes if a life threatening emergency occurs, which cannot be predicted prior to lift-off. This report describes the development, operations, and results in the aeromedical transport of 1047 patients from January 2, 1981 to December 31, 1982. Trauma transports accounted for 47.5%, nonsurgical problems 47.8% and nontraumatic surgical patients representing the remaining 4.7%. The in-flight mortality was 0%. This type service is not appropriate for all hospitals to provide, but should be considered by major trauma and cardiac referral centers.

Adolescent↗
PubMed1983

Change in state of nerve growth factor receptor. Modulation of receptor affinity by wheat germ agglutinin.

The binding of 125I-labeled nerve growth factor (NGF) to human melanoma cell (A875) membranes, detergent-soluble membrane extracts, and membrane extracts reconstituted into phospholipid vesicles was significantly increased when binding was carried out in the presence of wheat germ agglutinin (WGA). In the absence of WGA, all 125I-NGF binding was rapidly eliminated by trypsin treatment or rapidly dissociated in the presence of a high concentration of unlabeled NGF. However, in the presence of WGA, up to 75% of 125I-NGF bound was resistant to trypsin digestion and was only slowly dissociated by a high concentration of unlabeled NGF. The effects of WGA can be blocked or reversed by N-acetylglucosamine. Both WGA and NGF rapidly associate with soluble extracts and reconstituted vesicles and, at the concentrations used here, reach binding equilibrium within 2 min. The conversion to slowly dissociating, trypsin-resistant binding, however, was not complete for at least 10 min. Both WGA and NGF are required for maximum accumulation of trypsin-resistant, slowly dissociating binding. The order of addition of NGF and WGA has no effect on the rate of conversion of NGF-receptor, and the conversion occurs after both NGF and WGA are present. The amount of conversion is dependent on the incubation temperature, and significantly greater conversion occurs at 37 than at 0 degrees C. The generation of the trypsin-resistant, slowly dissociating state of NGF-receptor is consistent with a time- and temperature-dependent conformational change in NGF-receptor which occurs after interaction of both NGF and WGA with the receptor or closely associated structures.

Cell Line↗
PubMed1983

Purification of the receptor for nerve growth factor from A875 melanoma cells by affinity chromatography.

The receptor for nerve growth factor (NGF) has been purified to near homogeneity from octylglucoside extracts of A875 melanoma cell membranes by the use of repetitive affinity chromatography on NGF-Sepharose. Elution of purified receptor (NGF receptor) was accomplished with 0.15 M NaCl, pH 11.0, containing phosphatidylcholine and octylglucoside. Chromatography on two columns of NGF-Sepharose yielded a 1500-fold purification of the receptor, as assessed by 125I-NGF binding, and permitted recovery of 9% of the total binding activity in the soluble extract. Scatchard analysis of equilibrium binding of 125I-NGF provided similar Kd values for NGF receptors in soluble extracts of A875 membranes (2.2 nM) and with purified NGF receptor (3.1 nM). Examination of NGF receptor after electrophoresis on sodium dodecyl sulfate-polyacrylamide gels revealed the presence of two major peptides, of Mr = 85,000 and Mr = 200,000. Affinity labeling experiments, done with 125I-NGF and A875 cells, soluble extracts of A875 cell membranes, and purified receptor, show that both of these components of the NGF receptor can be specifically cross-linked to 125I-NGF.

Cell Line↗
PubMed1983

A comparison of binding properties and structure of NGF receptor on PC12 pheochromocytoma and A875 melanoma cells.

Rat PC12 pheochromocytoma and human A875 melanoma cells express nerve growth factor (NGF) receptors on their surfaces. Covalent crosslinking of bound 125I-NGF to PC12 or A875 intact cells or plasma membrane-enriched fractions resulted in labelling of a peptide doublet at Mr = 110,000 and a single labelled peptide at Mr = 200,000 for each of the cell and membrane preparations. However, a difference between equilibrium binding properties of NGF-receptor on PC12 and A875 cells was observed. PC12 cells exhibited biphasic binding properties with two apparent binding sites: KD = 5.2 nM sites and KD = 0.3 nM sites. The high-affinity PC12 binding sites were trypsin resistant, and 125I-NGF dissociated slowly from them. A875 cells exhibited sites with homogeneous properties (KD = 1.0 nM), all binding sites were trypsin sensitive, and 125I-NGF dissociated rapidly in the presence of unlabelled NGF. Membrane-enriched fractions from either cell type contained binding sites with a uniform low affinity (KD = 3 nM) that were trypsin sensitive, and 125I-NGF rapidly dissociated from them. Sixty to 80 percent of binding sites in membranes could be converted to the high-affinity, trypsin-resistant state by addition of wheat germ agglutinin (WGA). The loss of high-affinity, trypsin-resistant sites from PC12 cells during preparation of plasma membrane fractions does not appear to be the result of selective isolation of low-affinity sites or proteolytic degradation since there is a loss of 125I-NGF binding immediately after cell lysis which is not blocked by protease inhibitors. Also, high-affinity, trypsin-resistant binding sites are not found associated with other cell fractions. The differences between receptor properties on PC12 cells and on A875 cells apparently are the result of differences in the respective intracellular environments. Thus, significant structural homology exists between receptors on A875 and PC12 cells. Cell components other than the binding unit of the NGF receptor may be responsible for the different properties of receptor.

Adrenal Gland Neoplasms↗
PubMed1981

Variations in Kinetic Properties of Ribulose-1,5-bisphosphate Carboxylases among Plants.

Studies of ribulose-1,5-bisphosphate (RuBP) carboxylase from taxonomically diverse plants show that the enzyme from C(3) and crassulacean acid metabolism pathway species exhibits lower K(m)(CO(2)) values (12-25 micromolar) than does that from C(4) species (28-34 micromolar). RuBP carboxylase from aquatic angiosperms, an aquatic bryophyte, fresh water and marine algae has yielded consistently high K(m)(CO(2)) values (30-70 micromolar), similar in range to that of the enzyme from C(4) terrestrial plants. This variation in K(m)(CO(2)) is discussed in relation to the correlation between the existence of CO(2)-concentrating mechanisms for photosynthesis and the affinity of the enzyme for CO(2). The K(m)(RuBP) of the enzyme from various sources ranges from 10 to 136 micromolar; mean +/- sd = 36 +/- 20 micromolar. This variation in K(m)(RuBP) does not correlate with different photosynthetic pathways, but shows taxonomic patterns. Among the dicotyledons, the enzyme from crassinucellate species exhibits lower K(m)(RuBP) (18 +/- 4 micromolar) than does that from tenuinucellate species (25 +/- 7 micromolar). Among the Poaceae, RuBP carboxylase from Triticeae, chloridoids, andropogonoids, Microlaena, and Tetrarrhena has yielded lower K(m)(RuBP) values (29 +/- 11 micromolar) than has that from other members of the grass family (46 +/- 10 micromolar).

Journal Article↗
PubMed1980

Hydrocortisone suppression test and discriminant analysis in differential diagnosis of hypercalcaemia.

Experience is reported of the hydrocortisone suppression test in 140 hypercalcaemic patients, comprising 98 new cases of hyperparathyroidism and 42 cases of non-parathyroid malignant disease. The diagnostic accuracy of the test was compared in 168 patients with that of discriminant analysis, the discriminant functions being derived from plasma inorganic phosphate, alkaline phosphatase, chloride, bicarbonate, and urea, and the erythrocyte sedimentation rate. The hydrocortisone test and discriminant analysis each achieved a diagnostic accuracy of about 93% in 148 patients with either non-parathyroid malignant disease or hyperparathyroidism without osteitis fibrosa. When both tests pointed to the same diagnosis, they were wrong in less than 1% of cases. The hydrocortisone test was not helpful in patients with osteitis fibrosa. Both tests can be performed in any hospital with reliable standard laboratory services. Used in combination they have a high predictive value in distinguishing hypercalcaemia of parathyroid origin from that due to non-parathyroid malignant disease and have not led to errors of clinical importance. They should continue to play a major role in the differential diagnosis of hypercalcaemia until a prompt and reliable service finally establishes parathyroid hormone assay as the definitive laboratory procedure.

Adult↗
PubMed1980

Potentiation of cigarette smoking and radiation: evidence from a sputum cytology survey among uranium miners and controls.

To assess the effect of cigarette smoking and of exposure to radon daughters, a prospective survey consisting of periodic sputum cytology evaluation was initiated among 249 underground uranium miners and 123 male controls. Sputum cytology specimens showing moderate atypia, marked atypia, or cancer cells were classified as abnormal. As compared to control smokers, miners who smoke had a significantly higher incidence of abnormal cytology (P = .025). For miner smokers, the observed frequencies of abnormal cytology were linearly related to cumulative exposure to radon daughters and to the number of years of uranium mining. A statistical model relating the probability of abnormal cytology to the risk factors was investigated using a binary logistic regression. The estimated frequency of abnormal cytology was significantly dependent, for controls, on the duration of cigarette smoking, and for miners, on the duration of cigarette smoking and of uranium mining.

Adult↗
PubMed1980

Variations in K(m)(CO(2)) of Ribulose-1,5-bisphosphate Carboxylase among Grasses.

A survey of the K(m)(CO(2)) values of ribulose-1,5-bisphosphate carboxylase from 60 grass species shows that enzyme from C(3) grasses consistently exhibits lower K(m)(CO(2)) than does that from C(4) grasses. Systematically ordered variation in K(m)(CO(2)) of ribulose-1,5-bisphosphate carboxylases from C(3) and C(4) grasses is also apparent and, among C(4) grasses, this shows some correlation with C(4) types.

Journal Article↗
PubMed1979

An ultrastructural study of lymph nodes in antilymphocyte serum-treated mice.

The cytoarchitecture of regional axillary lymph nodes of C57BL/6 mice with DBA/1 skin allografts were examined by light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Lymph nodes from skin-grafted mice injected with rabbit anti-mouse lymphocyte serum (ALS) or normal rabbit serum (NRS) were examined ultrastructurally for the pattern of distribution, density and surface topography of their cellular constituents. The lymph node cortex consisted of smooth surface polyhedral-shaped cells tightly packed in the reticulum. A homogeneric population of lymphocytes more spherical in shape and more loosely distributed occupied the follicular region of the cortex. These cells exhibited surface microvilli and were similar in appearance to the free lymphocytes observed in the sinusoidal spaces. Post-capillary venules containing highly villous lymphocytes were observed in the deep cortex. Degradation of cellular organization and cell damage was observed in lymph nodes from ALS-treated mice. These alterations were believed to be a direct effect of ALS. This conclusion was based on the character of the cell damage observed in isolated lymphocytes, in suspension exposed to ALS with and without complement.

Animals↗
PubMed1978

Baboon veno-arterial cardiopulmonary bypass without anticoagulants.

Four hr veno-arterial cardiopulmonary bypass via a median sternotomy utilizing a membrane oxygenator was done in 15 baboons. A comparison of perfusion with and without anticoagulants was made. From this study systemic heparin had no advantage over no anticoagulants. These findings, in a clinically-relevant primate model, suggest that the scientific basis for the use of systemic heparin in membrane oxygenation is unclear.

Animals↗
PubMed1977

Opiate receptor: cooperativity of binding observed in brain slices.

Kinetic constants for binding of 3H-labeled morphine and naloxone were determined from Hill plot analyses and from experiments in which the concentration of tritiated drug was constant and that of nonlabeled drug varied. With brain slices, the binding of either drug exhibited strong positive cooperativity (Hill slope greater than 3); this was not observed in brain homogenates. Thus, in slices the relationship between opiate binding site and ligand may be more relevant physiologically and pharmacologically.

Animals↗
PubMed1977

Sclerosing mediastinitis with occlusion of pulmonary veins. Manifestations and management.

A case of mediastinal fibrosis with occlusion of the right inferior and middle lobe pulmonary veins is described. The patient had severe hemoptysis, and the diagnosis was established with thoracotomy. Review of the literature emphasizes the lethal nature of this syndrome if untreated. Resection of the involved bronchopulmonary tissue, when feasible, offers good palliation, although the long-term prognosis is unpredictable.

Adult↗