AIDS and the social irresponsibility of the insurance industry.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
K Chetty
Publications and source records attributed to K Chetty.
Antibodies to mycobacterial peptidoglycolipid and to crude protein antigens in sera from different categories of human subjects.
Sera from patients with disease caused by the Mycobacterium avium complex (M. avium and M. intracellulare), M. kansasii, or M. tuberculosis and from subjects who did not have a mycobacterial disease were tested by enzyme-linked immunosorbent assay against peptidoglycolipid antigens representing each of the 15 most common serovars of the M. avium complex and against crude protein antigen extracts of M. avium and M. tuberculosis. The highly specific peptidoglycolipid antigens yielded positive reactions in 83% of M. avium complex patients, 57% of active-tuberculosis patients, and 14% of subjects without mycobacterial disease. Reactions to more than 1 of the 15 peptidoglycolipid antigens were found only in patients with infections caused by mycobacteria, suggesting that a mycobacterial pulmonary lesion is readily colonized by mycobacteria other than the one that initiated the lesion. The two crude mycobacterial protein antigens were highly cross-reactive, with little if any capacity to discriminate between infections caused by any of the mycobacteria studied. Moreover, they did not appear to be more sensitive than the peptidoglycolipids. The data suggest that it is unlikely that a practical and reliable serological test can be developed that will distinguish between transient subclinical infection and significant disease caused by common environmental mycobacteria, such as members of the M. avium complex. Success in developing such a test for nonenvironmental mycobacteria, such as M. tuberculosis, appears more likely.
Antibodies, Bacterial↗
The impact of routine admission chest x-ray films on patient care.
We evaluated the impact of routine chest x-ray films, obtained on admission, on the treatment of patients on internal medicine wards of the Veterans Administration Medical Center, Long Beach, California--a population known to have a high prevalence of cardiopulmonary disease. The reasons for ordering chest films were determined prospectively, and three Department of Medicine faculty members reviewed the charts of admitted patients to determine the impact of chest-film results on patient care. Routine chest x-ray films were ordered for 294 (60 per cent) of the 491 patients studied. Abnormalities were noted in 106 (36 per cent) of these 294 patients. The findings were previously known, chronic, and stable in 86 patients; they were new in only 20. Treatment was changed because of chest-film results in only 12 (4 per cent) of the patients. In only one of these patients would appropriate treatment probably have been omitted if a chest film had not been obtained, and the patient's outcome was not improved by the treatment instituted. We conclude that the impact of routine admission chest x-ray films on patient care is very small, even in a population with a high prevalence of cardiopulmonary disease. We recommend that such films not be ordered solely because of admission.
Adult↗
Comparison of the effects of labetalol and hydrochlorothiazide on the ventilatory function of hypertensive patients with asthma and propranolol sensitivity.
Previous studies have shown that labetalol, a new alpha- and beta-adrenergic antagonist, is relatively safe for the treatment of hypertension in patients with chronic obstructive pulmonary disease (COPD). This multicenter study was designed to evaluate its effects in hypertensive patients with asthma and propranolol sensitivity. Hypertension was successfully controlled in 18 of 21 patients who received labetalol in increasing doses, up to 1,200 mg/day. The decrease in mean FEV1 (1.5 percent) two hours after the highest dose of labetalol was not statistically significant, although there was a gradual decline in mean baseline FEV1 during the four-week treatment period. Antihypertensive agents other than adrenergic antagonists should be considered for the management of hypertension in patients with asthma, especially those with marked reversibility of airflow. If treatment with beta-adrenergic antagonists is indicated, labetalol is recommended over other currently available agents.
Adolescent↗
Elastic fibers in the anulus fibrosus of the dog intervertebral disc.
A light microscopic investigation of the anulus fibrosus in cervical intervertebral discs of the dog was conducted to ascertain the arrangement and distribution of elastic fibers. Elastic fibers were observed in all lamellae of the anulus fibrosus. However, collagenous fibers were the predominant type of connective tissue fiber, and elastic fibers were randomly dispersed among them. Intralamellar (collagenous and elastic) fibers were vertically and obliquely oriented in both superficial and deep lamellae of the anulus fibrosus. All intralamellar fibers were densely and regularly arranged in superficial lamellae, but they were more loosely organized in deep lamellae. A narrow border of interlamellar, elastic fibers was observed between broader, contiguous lamellae in the superficial zone of the anulus fibrosus. Interlamellar elastic fibers wer vertically and obliquely arranged in superficial lamellae; however, they were radially oriented in deep lamellae. The deepest lamella of the anulus fibrosus consisted of a loose, three-dimensional network of intermeshing collagenous and elastic fibers. These observations suggest that elastic fibers are integral components of the articular and shock absorption mechanisms of the anulus fibrosus, and the cervical intervertebral disc of the dog is a suitable model for experimental investigation of the role of elastic fibers in intervertebral disc herniation.
Animals↗
The distribution and arrangement of elastic fibres in the intervertebral disc of the adult human.
Selected cervical and thoracic intervertebral discs were removed from twelve human adults at autopsy. The discs were prepared by the paraffin method, stained with orcein or by Verhoff's technique and examined with the light microscope for the presence of elastic fibres. Elastic fibres were located only in the lamellae of the anulus fibrosus and the superficial zones of the nucleus pulposus from regions of intervertebral disc that connected or interfaced with osseous vertebrae. Elastic fibres were longitudinally, circularly and obliquely arranged in lamellae of the anulus fibrosus and penetrated bony vertebrae as Sharpey's fibres. Elastic fibres assumed a three dimensional lattice work in the superficial zone of the nucleus pulposus and connected it to the hyaline cartilage end plate as Sharpey's fibres. Irregularly arranged elastic fibres interconnected the superficial zone of the nucleus pulposus and lamellae of the anulus fibrosus. Elastic fibres were a major histological component of the ligamenta flava and anterior longitudinal ligaments.
Aged↗
Effects of isosorbide dinitrate on pulmonary hypertension in chronic obstructive pulmonary disease.
Eighteen patients with chronic obstructive pulmonary disease with pulmonary hypertension were studied to assess the hemodynamic response to acute oxygen administration and to oral isosorbide dinitrate (ISDN). All 18 patients had baseline hemodynamic measurements and hemodynamic measurements during low-flow nasal oxygen. Following a second baseline measurement, patients received either oral ISDN (11 patients) or placebo (7 patients) in a randomized, double-blind protocol. Heart rate decreased with oxygen administration but there were no other significant hemodynamic changes. With oral ISDN, there was a significant fall in pulmonary artery and brachial artery pressure. Cardiac output, right atrial pressure, pulmonary wedge pressure, and pulmonary vascular resistance all fell but not significantly. We conclude that oral ISDN is effective in reducing pulmonary hypertension in patients with chronic obstructive pulmonary disease.
Blood Pressure↗
P pulmonale in status asthmaticus.
We studied 129 patients during acute, severe asthmatic attacks. Electrocardiograms showed P pulmonale in 49% of patients who had an arterial carbon dioxide tension (PaCo2) greater than or equal to 45 mm Hg and an arterial pH less than or equal to 7.37, whereas P pulmonale was present in only 2.5% of asthmatics who had a PaCO2 less than or equal to 44 mm Hg and a pH greater than or equal to 7.38 (p less than 0.001). P wave and QRS axes were 79 +/- 8 degrees and 80 +/- 20 degrees, respectively, in the presence of P pulmonale. When P pulmonale disappeared, the P wave and QRS axes shifted significantly to the left (p less than 0.001). Electrocardiographic P pulmonale persisted 12 to 60 hr after correction of hypoxemia, hypercapnia, and acidosis. In 7 patients with P pulmonale and respiratory acidosis, cardiac catheterization demonstrated normal artery pressures (PAPs) measured relative to atmospheric pressure. In 12 of these peak inspiratory pulmonary artery transmural pressures (PATPs) were increased. Since increased right heart transumural pressures could result in chamber distention, these data are consistent with the hypothesis that reversible P pulmonale in status asthmaticus is explainable on the basis of markedly negative tidal pleural pressures and increased right heart transmural pressures.
Adolescent↗
Comparison of noninvasive with hemodynamic data in patients with pulmonary hypertension due to chronic obstructive pulmonary disease.
Twenty-one patients with chronic obstructive pulmonary disease were studied with right heart catheterization. The mean pulmonary artery pressure (PAP) was compared with several noninvasive tests. The pulmonary lobar diameter/thoracic ratio correlated with the PAP, r = 0.677, P less than 0.01. The oxygen saturation and pH were used to derive a calculated value for PAP. The calculated PAP correlated with PAP values measured below 40 mm Hg, r = 0.787, P less than 0.01 but correlated very poorly with PAP values measured above 40 mm Hg. The electrocardiogram revealed at least one criterion for right ventricular abnormality in all 18 patients with pulmonary hypertension, but was too nonspecific to correlate with PAP. The hemoglobin concentration did not correlate with PAP. There was such wide variation between the measured PAP and the various noninvasive tests that these noninvasive tests could not be used to accurately predict the PAP in an individual patient.
Blood Gas Analysis↗
The effect of salicylate infusion on the alveolar epithelial membrane in the isolated perfused lung.
We observed two patients with aspirin (ASA) ingestion (blood levels of 87 and 56.5 mg/100 ml) who presented with noncardiogenic pulmonary edema (adult respiratory distress syndrome. To determine if ASA had a direct effect on the alveolar epithelial membrane, we established an in vitro isolated lung model and perfused it with platelet free plasma. T1/2 (in minutes), the time for 50% equilibration between the plasma and the saline filled lung, was determined before and after 500 mg salicylate infusion for various molecular weight dextrans. T1/2 decreased significantly (p less than 0.05) as follows: 3000 MW dextran, 2273 +/- 932 to 961 +/- 375; 40,000 MW dextran, 4059 +/- 1550 to 733 +/- 275; 70,000 MW dextran, 11,730 +/- 2750 to 7700 +/- 2230. Histamine levels in plasma and lung liquid did not change significantly with ASA infusion. We conclude that ASA directly increases alveolar epithelial permeability to dextrans less than 70,000 MW.
Aged↗
Tumor necrosis factor receptor 2 plays a minor role for mycobacterial immunity.
Tumor necrosis factor (TNF) signalling via the TNF receptor 1 (TNF-R1) is required for host resistance to mycobacterial infection. The role of TNF-R2 in anti-mycobacterial immunity is not known. Therefore, we compared TNF-R1 and TNF-R2 knockout (KO) mice infected with Mycobacterium bovis BCG (10(7) CFU, i.v.). While the bacterial burden of TNF-R1-deficient mice was significantly increased and the mice succumbed to infection between 4 and 5 weeks, TNF-R2 KO mice were less sensitive, and only 3 of 10 mice died within 12 weeks. Wild-type (WT) mice were resistant to BCG infection. The inability to clear the infection of TNF-R1 KO mice was associated with a reduced delayed-type hypersensitivity (DTH) response to purified protein derivative and severe impairment in forming granulomas with reduced macrophage recruitment and activation, and diminished expression of adhesion molecules. By contrast, TNF-R2 KO mice developed normal DTH response and mature mycobactericidal granulomas as the WT mice. Therefore, anti-mycobacterial immunity is largely dependent on TNF signalling via the TNF-R1, while activation of TNF-R2 plays a minor role.
Animals↗