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Biomedical subjects

C Davis

Publications and source records attributed to C Davis.

At least 379 records · Page 21Linked to original sources
PubMed1980

The use of radioactive isotopes for analysis of cutaneous allergic responses.

Local exudation at the sites of allergic and histamine-induced cutaneous reactions, was measured with an in vivo double-labelling procedure, based upon local serial simultaneous measurements of indium-113 m (113mIn) labelled transferrin and technitium-99m labeled red blood cells (99mTc RBC). Analyses depended upon the reaction index i.e. comparison of the ratio of 113mIn/99mTc counts at the reaction site with the ratio of 113mIn/99mTc at the corresponding unreacted site in the skin of the opposite arm. Reaction indices were initially significantly elevated at the sites of histamine and allergic reactions. After the first hour, there was a progressive reduction at histamine sites indicating a tapering of the local accumulation of indium-labelled transferrin. By contrast allergic reaction sites showed a continuing increase in the reaction index after one hour. During the first hour the curves were comparable, but they diverge and were significantly different after one hour (0.05 greater than P greater than 0.02). This is consistent with the known occurrence of late cutaneous reponses at the site of allergic but not histamine reactions.

Dermatitis, Contact↗
PubMed1980

Importance of airway closure in limiting maximal expiration in normal man.

To elucidate the importance of airway closure in limiting maximum expiration, two complementary plethysmographic techniques have been used to estimate the volume of and pressure within the trapped thoracic gas. Three young (19-23 yr) and three older (43-66 yr) subjects were studied. The first study defined the curve of possible pressure-volume relationships for the trapped gas; the second study attempted to estimate the volume of trapped gas. In the first study the subject in a Mead plethysmograph expired through a pneumotachograph and back into the box. A reduction in box volume greater than that caused by drying and cooling of expired gas implies gas compression due mainly to airway closure. In the second study a known volume of air was withdrawn from the mouth at full expiration and changes in box volume and mouth pressure were recorded. The apparent volume in pressure communication with the mouth (Vpc) was calculated using Boyle's law. In the young subjects we did not detect thoracic gas compression although there was evidence of trapped gas (RV-Vpc greater than 0). In the older subjects there was a larger volume of trapped gas that was compressed to pressures of more than 22 cmH2O. Airway closure appears to limit maximal expiration in older subjects.

Adult↗
PubMed1979

Mass culture of human corneal endothelial cells.

Human corneal endothelial cells have been grown in mass culture for the first time to our knowledge. Cultures from donors who were under 20 years of age grew well. Cells from older donors were difficult to grow or did not grow at all. Initial outgrowth usually began one week after explantation. After an initial lag phase, mass increased by 15% weekly, and confluency was approached in eight to nine weeks. The lag phase of growth correlated with the age of the donor. A basal lamina was secreted by human corneal endothelial cells in culture. Chromosomal counts demonstrated a modal number of 46. With this technique, sufficient human corneal endothelial cells may be obtained for biochemical investigation.

Adolescent↗
PubMed1979

Congenital lobar emphysema.

Congenital lobar emphysema is a rare disorder thay may present outside the newborn period. It is generally best treated surgically by excision of the affected lobe. We describe a 6 1/2-week-old infant in whom the initial auscultatory and roentgenographic findings were confusing and of no help in making the diagnosis. The etiology of congenital lobar emphysema remains unclear.

Diseases in Twins↗
PubMed1979

Bacterial aggregating activity in human saliva: simultaneous determination of free and bound cells.

Two new assays for saliva-mediated aggregation of oral bacteria have been developed, based on the use of [3H]thymidine-labeled cells. One assay separates free cells from aggregated cells by centrifugation through sucrose, whereas the other utilizes membrane filters (8 micrometers, Nuclepore) to effect the separation. Comparison of these assays with the turbidity method reveals that they are faster (X20 to 40) and require 10 times less saliva and bacteria. The aggregation of Streptococcus sanguis M5, as determined with these assays, is complete in 5 min and is dose dependent on added cells and saliva. The reaction exhibits a temperature optimum of 42 degrees C with no reaction at 0 degrees C. If the pH is reduced to below 5, saliva-dependent aggregation is inhibited. The salivary factor(s) are heat labile, losing 100% of their activity after 100 degrees C, 10 min or 70 degrees C, 30 min.

Bacterial Physiological Phenomena↗
PubMed1979

The architectural design of a psychotherapeutic milieu.

The physical environment of a treatment program affects patient outcome, but how and to what degree is not known. However, decisions about the design of the environment must be made, and they must be made in the face of cost and building-code constraints and widely varying patient characteristics and treatment models. The authors describe the design principles and philosophies they followed in the remodeling of an in-patient treatment and research service in a university psychiatric hospital and indicate where cost and code constraints resulted in a less than ideal solution. They point out that many apparent amenities, such as a ward kitchen, are significant milieu therapy resources, and they advocate the involvement of all levels of staff in the planning process.

Adolescent↗
PubMed1978

Project lithium.

Explore the source record for details and available documents.

Humans↗
PubMed1978

Lack of effect of bromocriptine on ACTH levels in patients with bilateral adrenalectomy for pituitary-dependent Cushing's syndrome.

Bromocriptine lowers plasma ACTH levels in patients with pituitary-dependent Cushing's syndrome. It seemed possible that the drug would also be effective in patients who had been adrenalectomised for the disease. The effect of 5.0 mg of bromocriptine on plasma ACTH and prolactin levels in 13 patients, bilaterally adrenalectomised for pituitary-dependent Cushing's syndrome, was therefore studied. In only one patient was a fall in plasma ACTH observed. This may be of doubtful significance since marked spontaneous fluctuation in plasma ACTH levels were found in the five patients tested. Bromocriptine lowered the plasma prolactin in all of the patients, including two with hyperprolactinaemia.

Adolescent↗
PubMed1978

Variation in the disposition of morphine after i.m. administration in surgical patients.

The disposition of morphine when administered by i.m. injection was studied in 36 patients receiving morphine as part of premedication before general anaesthesia, and in five patients who received morphine as a postoperative analgesic after median sternotomy for coronary artery surgery (PCA group). Maximum plasma concentration of morphine (CP max) was 75.3 +/- 6.0 (mean elimination rate constant (k) 4.85 X 10(-3) min-1 and half-life (T1/2) = 143 min for the preanaesthetic group. The corresponding values for PCA group were CPmax = 58.0 +/- 18.0 ng ml-1 (range 30--130 ng ml-1), k = 5.63 X 10(-3) min-1 and T 1/2 = 123 min. Analysis of variance showed no differences between the groups. Within the preanaesthetic group, there was a significant difference in k between males (k = 4.01 X 10(-3) min-1) and females (6.30 X 10(-3) min-1, P less than 0.01). The corresponding T 1/2 for males was 173 min; and 110 min for females. The variation in the disposition of morphine is thought to be the result of variations in resting muscle blood flow and inadvertent injection into adipose tissue. There were no significant differences between males and females in the preanaesthetic group with respect to age, Cpmax or time from injection to Cpmax.

Adult↗
PubMed1978

Transient ischemic attacks: a prospective study of 225 patients.

Between the years 1964 and 1973, 225 patients with transient ischemic attacks (TIAs) due primarily to atherosclerosis were evaluated and treated. They have now been followed for from 3 to 14 years (average 5.5 years). As of 1976, 82 of the 225 patients were dead, 21 from cerebral infarction, 52 from heart disease and nine from other causes. Of the 56 untreated patients, 11 (19 percent) had cerebral infarctions, four (7 percent) of which were fatal; six (11 percent) were still having TIAs. Of the 45 patients medically treated, 10 (24 percent) had cerebral infarctions, three (7 percent) of which were fatal; 11(25 percent) still experienced TIAs. In the surgical group of 124, 27 (21 percent) had postoperative cerebral infarctions, seven (6 percent) of which were fatal; 23 (18 percent) had cerebral infarctions during follow-up, of which seven (6 percent) were fatal; and 15 (12 percent) were still having TIAs. No statistically significant differences (p less than 0.05) related to cerebral infarction or TIAs developed among the three groups. The majority (23 percent) eventually succumbed to myocardial infarction, leading us to conclude that great emphasis must be placed upon TIAs as a warning for cardiac as well as cerebrovascular disease.

Aged↗