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Biomedical subjects

A F Wilson

Publications and source records attributed to A F Wilson.

At least 145 records · Page 8Linked to original sources
PubMed1980

Determination of pulmonary tissue volume, pulmonary capillary blood flow and diffusing capacity of the lung before and after hemodialysis.

In order to better understand changes in lung function before and after dialysis, we studied eight patients with end-stage renal disease undergoing chronic hemodialysis. Pulmonary tissue volume (Vt), pulmonary capillary blood flow (Qc), the diffusion capacity for carbon monoxide (DLCO), arterial blood gases and body weight were measured before and after dialysis. A single breath, constant expiratory flow technique for determination of of DLCO, Qc and Vt was used. DLCO, Qc, arterial carbon dioxide, and body weight were reduced post dialysis (P less than or equal to .01) while Vt failed to change. The alveolar-arterial oxygen difference rose 123 mmHg (P = .01). These results are consistent with pulmonary microembolization during dialysis with deterioration of gas exchange and Qc. These changes appear to occur independent of significant changes in Vt. Possible physiologic mechanisms are discussed.

Adult↗
PubMed1979

Large airway constriction in allergic rhinitis: response to inhalation of helium-oxygen.

Pulmonary function results were compared in 15 allergic rhinitis and 30 normal subjects. Airways resistance (RAW) was higher (p less than 0.01) and specific conductance (SGAW) and lower (p less than 0.01) in the rhinitis group. Maximal expiratory flow (VeMax), lung volumes, and results of tests measuring airways closure, distribution of ventilation, diffusing capacity, volume of isoflow, and density-dependence of VeMax at 50% of vital capacity (deltaVeMax50) did not differ significantly between the two groups. Following inhalation of isoproterenol, RAW decreased and SGAW and VeMax increased significantly in both groups. On the other hand, delta-VeMax50 decreased significantly in the rhinitis group (p less than 0.01) and increased significantly in the control group (p less than 0.05). In addition to comparing pulmonary function in rhinitis patients and control subjects, physiologic measurements were also made on two separate occasions in the rhinitis subjects (minimal or no symptoms; very symptomatic). Although rhinitis symptomatology varied considerably (p less than 0.001), pulmonary function results were not significantly different. Hence we conclude that: (1) Rhinitis subjects have large airway constriction which does not vary with season or symptoms. (2) As in normal control subjects, airflow limitation occurs in the large airways of rhinitis subjects. (3) The predominant site of isoproterenol-associated bronchodilatation differs between allergic rhinitis and normal subjects.

Adult↗
PubMed1979

Relative sensitivities and specificities of tests for small airways obstruction.

This study compared several physiologic maneuvers for detecting small airways obstruction (SAO). Volume of isoflow best separated young smokers (average age--27.6; average cigarette consumption--9.3 pack years) from nonsmokers; this was true for comparisons of both population means and incidence of individual abnormality. However, assessment of individual abnormality by any test was greatly influenced by the criteria used to define abnormality. The best combination of test sensitivity and specificity was achieved by using the 95% confidence limits derived from a control population from the same laboratory. Even so, test results did not correlate significantly with pack years of cigarette smoking. Then, although tests for SAO are very sensitive, their prognostic value in young smokers is uncertain since abnormality presumably should correlate with extent of smoking.

Adult↗
PubMed1978

Indirect calorimetry as a guide to caloric replacement during total parenteral nutrition.

Fifty patients were studied by indirect calorimetry to assess caloric needs. Seventeen patients received total parenteral nutrition (TPN) in a fixed dose of 45 +/- 3 kcal/kg. Thirty-three patients were studied after acute injury. Indirect calorimetry and the basal energy expenditure equation (BEEE) were compared. In male patients receiving TPN, indirect calorimetry more closely approximated caloric needs than did the BEEE X 1.75. In female patients, the BEEE X 1.75, indirect calorimetry value, and calories infused were more equivalent, and positive nitrogen balance was consistently achieved. In thirty-three trauma patients, indirect calorimetry and the BEEE were compared. Indirect calorimetry consistently predicted higher caloric expenditure than did the BEEE X 1.75. In assessing caloric requirements in acutely catabolic patients, the BEEE X 1.75 appears to be inadequate. The BEEE does not take into account changes in temperature or degree of illness. Indirect calorimetry is easy to perform and gives more pointed information about the patient's caloric needs.

Adolescent↗
PubMed1978

Adrenocortical activity during meditation.

We studied acute plasma cortisol and testosterone concentration changes during the practice known as "transcendental meditation" (TM) and during control rest. Three groups of normal, young adult volunteers were studied: a group of controls, these same controls restudied as practitioners after 3 to 4 months of TM practice, and a group of long-term, regular TM practitioners (3 to 5 years of practice). No change was found in controls during rest. Cortisol declined, but not significantly, in restudied controls, while cortisol decreased significantly in long-term practitioners during meditation and remained somewhat low afterward. No change in testerone concentration was noted during either rest or TM. Apparently, the practice of TM becomes associated with psychophysiologic response(s) which acutely inhibit pituitary-adrenal activity.

Adrenal Cortex↗
PubMed1978

Redistribution of blood flow in acute hypometabolic behavior.

Cardiac output, renal and hepatic blood flows, arterial lactate concentration, and minute volume were measured before, during, and after 40 min of rest induced either by the practice known as "transcendental meditation" (TM) or by an ordinary eyes-closed rest-relaxation period. Two groups of normal young adults were studied: one group consisted of regular practitioners of TM and the other of similar individuals studied prior to learning this technique. Marked declines of renal blood flow were noted in both groups. Decline of hepatic blood flow, increased cardiac output, decreased arterial lactate, and minute volume were also recorded in the TM-induced rest period. These changes imply a considerable increase of nonrenal, nonhepatic blood flow during TM (44%) and, to a lesser extent, during rest (12%). Increased cerebral and/or skin blood flow is hypothesized to account for part of the redistributed blood flow in the practitioner.

Cardiac Output↗
PubMed1978

Peripheral neuropathy related to misonidazole: incidence and pathology.

The human tolerance to multiple dosages of misonidazole (Ro-07-0582) was studied in 28 patients with different types of malignant neoplasias. The mean total dose for this group of patients was 16.2 g. The main toxicity was peripheral neuropathy with an overall incidence of 35%. This neuropathy occurred more frequently and with greater severity when the drug was administered 3 times a week and when patients received total doses of over 18 g. The best tolerated schedule appears to be once or twice a week up to total dosages of 18 g or less (approximately 11 g/m2). Electron microscopy of a sural nerve biopsy from an affected patient revealed residual of previous distal axonal degeneration, with some segmental demyelination and remyelination, which affected both large and small myelinated nerve fibres.

Drug Administration Schedule↗
PubMed1978

Pulmonary ultrastructure of the late aspects of human paraquat poisoning.

The pulmonary ultrastructure of the late aspects of a case of human paraquat poisoning is investigated and compared with normal human pulmonary ultrastructure. Alveoli in the paraquat patient are numerically reduced in comparison to the control. They are filled with edematous proteinaceous plasma-like fluid containing erythrocytes, macrophages, leukocytes, fibroblast-like cells, platelets, and fibrin. These alveoli are lined by granular pneumocytes. Interstitial areas in the paraquat patient are greatly expanded and there are no alveolar septums. Interstitial areas contain proteinaceous plasma-like material, collagen, fibrin, platelets, mature fibroblasts, plasma cells, many leukocytes, numerous erythrocytes, and capillaries. Capillary permeability seems to be enhanced in the paraquat patient either by vesicles forming transendothelial channels or pores or by disruption of endothelial cells.

Adolescent↗
PubMed1977

Behavioral alteration of plasma phenylalanine concentration.

The concentration of 13 neutral and acidic plasma amino acids was measured before, during and after either 40 min of control relaxation or 40 min of the process known as transcendental meditation (TM). An electro-oculogram, electroencephalogram, and electromyogram were simultaneously monitored in these subjects. Increased phenylalanine concentration was noted during TM practice with no change during control relaxation; no difference between the groups of total time slept or sleep stage percent was observed. The stability of phenylalanine concentration in controls and lack of correlation of increased phenylalanine with sleep in the long-term practitioners seem to suggest a relationship of the phenylalanine increase to TM practice.

Adult↗