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Biomedical subjects

J Ware

Publications and source records attributed to J Ware.

122 records · Page 7Linked to original sources
PubMed1982

Induced hyperosmolality effects on extracellular fluid volume, lymph flow and osmolar equilibrium: studies in the rat.

The effects of experimentally induced hyperosmolality has been studied in rats. Renal vascular pedicle ligation was performed on all animals to prevent renal clearance of the infused solute, xylose, and allow accurate ECF space determinations with 51Cr EDTA. Small volume hyperosmolar xylose infusions caused parallel elevation of the osmolality of thoracic duct lymph and arterial plasma. A positive correlation was obtained between lymph osmolality and flow alterations. The maximal osmolality elevation of 22 mosm X kg-1 H2O was associated with an intracellular fluid mobilisation which was equal to 7.1% of the ECF space. The infused and mobilised fluid volumes were distributed unequally between the intra and extra vascular compartments of the ECF.

Animals↗
PubMed1982

51Cr EDTA determinations of the extracellular fluid volume in hemorrhage: a study with fed and starved rats.

Extracellular fluid volumes have been determined in fed and 24-30 h starved rats, before and after 60 min of hemorrhagic hypotension at 70 mmHg. Bilateral renal vascular ligation was carried out to prevent clearance of the isotope tracer used, 51Cr EDTA. The time taken for a bolus of the tracer to distribute itself in its space, was determined in fed and starved animals after the standard period of hypotension. This was found to be 37 min for fed animals, and 50 min for those which had been starved. When the isotope ECF space was compared before and after hemorrhage in fed animals, it was unchanged, despite an estimated blood volume loss of 39%. The isotope ECF space was reduced 5.5% after hemorrhage in animals which had been starved. It is concluded that fed rats mobilised intracellular fluid to the interstitium in hemorrhage, whereas, starved animals did not. This finding of variable fluid homeostasis is ascribed to the different nutritional status of the animals investigated, and has considerable implications.

Animals↗
PubMed1982

Glucose, insulin and osmolality changes in rats sustaining different hemorrhage volumes.

Plasma glucose, osmolality and insulin have been investigated during hemorrhage in non-starved rats. The rate of blood loss leading to hemorrhages of 44% and 55% of the estimated original blood volume determined the patterns of response. Substantial hyperglycemic hyperosmolality and insulin values appropriate for the raised levels of glucose were observed in the animals bleeding more rapidly. The slower rate of hemorrhage was associated with only moderate hyperglycemia and hyperosmolality, while the insulin values rose to very high levels, 45 times basal. It is postulated that altered glucose-insulin metabolism in haemorrhage may have important consequences for fluid homeostasis, and the rate of bleeding is the fundamental factor steering this effect.

Animals↗
PubMed1982

Osmolar changes in haemorrhage: the effects of an altered nutritional status.

Fed and 24-30 hour starved rats were submitted to haemorrhagic hypotension, 70 mmHg, with a modified Wigger's system. Neuroleptanalgesia was used to ensure a normal degree of stress reactivity. Despite fed animals losing 53% of their original blood volume (BV) and starved animals 47% (BV = 6% prestarved body weight), blood gas data and creatinine levels confirmed a well intact and compensated status in both groups. Fed animals compensated for the greater haemorrhage with a haematocrit reduction which was double that in starved animals. When the alterations in osmole skeletons were compared, evidence for an intracellular fluid (ICF) shift to the interstitium was obtained in fed rats. Their NaCl space increased by 5.5%. Glucose increased its osmolar effect by 224% among fed animals and was reduced in those which had been starved. Glucose was identified as the solute causing an acute mobilisation of ICF to the interstitium.

Animals↗
PubMed1981

Factors affecting the size of platelet aggregates in blood.

Factors affecting the size distribution of platelet aggregates formed in whole blood were measured using an electronic particle counter. Lysis of red cells after dilution of blood for analysis allows detection of smaller aggregates without altering aggregate measurement. Differences in platelet response to increasing concentrations of ADP are detected by an increase in the mean size of platelet aggregates while the total volume of aggregates varies linearly with the volume of available platelets (r = .99). The mean aggregate size varies directly with the total volume of aggregates formed (r = .99). Mean aggregate size is inversely related to the packed red cell volume. As the reactivity of platelets is reduced by incubation with aggregation inhibitors at increasing concentrations, the mean size of aggregates becomes smaller, followed by a decrease in the total volume of aggregates. The total volume and mean size of aggregates formed after incubation with collagen and epinephrine, but not ADP, increases with time after venepuncture.

Adenosine Diphosphate↗
PubMed1981

Are clinical trials in coronary heart disease oversold or undersold?

Randomized clinical trials constitute the formal experiments in therapeutics. Many such trials in coronary heart disease have terminated inconclusively or in controversy. In this editorial, we analyze some of the methodologic issues that may lead to controversy; the main reason for the low success rate may lie in insufficient understanding of the complex biology of the disease and in failure to select the appropriate models for therapy. We argue that these difficulties only strengthen the need for the rigorous experimental approach to the evaluation of therapies for coronary heart disease.

Aspirin↗
PubMed1980

Channeling health: a review of the evaluation of televised health campaigns.

This article reviews efforts to assess the effectiveness of television programs on changing health behaviors. The relatively limited literature to date has featured primarily correlational studies which permitted no causal conclusions. The few experimental studies available present a mixed picture. Numerous methodologic problems beset any effort at assessment of effectiveness. Perhaps the greatest difficulty is operationalizing a design that permits true experimental manipulation on a relevant sample without contamination. The several methodologic problems and some potential means of surmounting them are discussed.

Attitude to Health↗
PubMed1978

Echocardiographic measurements in normal subjects. Growth-related changes that occur between infancy and early adulthood.

Echocardiographic measurements of the left ventricular dimensions and wall thicknesses at end diastole and end systole, aortic root and left atrial dimensions, mitral valve E-F slope, left ventricular ejection fraction, percent fractional shortening of the left ventricular internal dimension, estimated left ventricular mass and percentage systolic thickening of the ventricular septum and left ventricular free wall were obtained in 105 normal subjects ranging from one day to 23 years of age. Each parameter was found to follow a linear regression upon one of three functions of the body surface area. The internal dimensions of left ventricle, the left atrium, and the aortic root, and the mitral valve E-F slope varied in a linear relation to the cube root of the body surface area. Thickness of the ventricular septum and left ventricular free wall varied in a linear relation to the square root of the body surface area. Estimated left ventricular mass varied linearly with the direct measurement of body surface area. Ejection fraction, percent fractional shortening of the left ventricle and percent systolic thickening of the ventricular septum and left ventricular free wall were independent of body surface area despite a marked increase in the size of the left ventricle during normal growth and development.

Adolescent↗
PubMedDate not supplied

A model for predicting the counseling practices of physicians.

The authors present a conceptual model of the determinants of the counseling practices of physicians and an empirical test of the model. Seventy-six per cent of a 50% random sample of physicians in a western county medical society completed a questionnaire (n = 151). This instrument measures the aggressiveness, the indications and techniques used by physicians in counseling patients about smoking, exercise, weight control and alcohol use. The independent variables assessed by this instrument are motivations, perceived skills and barriers, medical specialty, and personal health habits. Significant associations were found between the counseling practices reported and physicians' personal health habits, attitudes and specialties. Non-surgeons counseled more patients, counseled more intensively, and used a greater variety of techniques than surgeons and obstetrician-gynecologists. In general, physicians who had poor health habits did not fully counsel patients about those habits; however, physicians attempting to improve poor habits counseled patients significantly more often than physicians who were not trying to change their own behavior. Health maintenance efforts among physicians may have a multiplier effect.

Alcohol Drinking↗