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Biomedical subjects

B Lahiri

Publications and source records attributed to B Lahiri.

At least 19 recordsLinked to original sources

The trajectory of change over multiple outcome areas during comprehensive outpatient pulmonary rehabilitation.

Although pulmonary rehabilitation has proven effectiveness in multiple outcome areas, the optimum duration of this intervention is not clear. We evaluated in an observational study the trajectory of change in upper and lower extremity exercise performance, exertional dyspnea and health status over the course of 12 weeks (24 sessions) of pulmonary rehabilitation in individuals with chronic obstructive pulmonary disease. Demonstrating a plateau in response in these areas might be of practical use for pulmonary rehabilitation programs. We measured outcomes at baseline and at four-session (two week) intervals over the course of our comprehensive outpatient pulmonary rehabilitation program. These included treadmill endurance time at approximately 85% of initial maximal workrate, the number of arm lifts per minute, dyspnea at isotime during treadmill walking and the Chronic Respiratory Disease Questionnaire (CRQ) total score. Thirteen patients with chronic obstructure pulmonary disease (COPD) (five male, eight female) were studied; their age was 66 +/- 8 years and their FEV1 was 34 +/- 11% of predicted. Improvement was noted in all four outcome areas very early in the course of pulmonary rehabilitation. Treadmill endurance time and arm lifts increased significantly over baseline by the fourth and eighth session, respectively, and both increased in a near-linear fashion throughout pulmonary rehabilitation. Exertional dyspnea and CRQ also improved very early, with each showing a significant change from baseline by the fourth session. Their improvement, however, appeared to plateau relatively early during the course of pulmonary rehabilitation. Although the numbers studied are small and the applicability of these results to other programs is undetermined, this study does suggest that 20 or more sessions are needed for optimal acute changes in exercise performance, but improvement in dyspnea and quality of life may occur earlier.

Aged↗

Structural requirements for glycosaminoglycan recognition by the Lyme disease spirochete, Borrelia burgdorferi.

Borrelia burgdorferi, the Lyme disease agent, binds glycosaminoglycans (GAGs) such as heparin, heparan sulfate, and dermatan sulfate. Heparin or heparan sulfate fractions separated by size or charge were tested for their ability to inhibit attachment of B. burgdorferi to Vero cells. GAG chains of increasing length and/or charge showed increasing inhibitory potency, and detectable heparin inhibition of bacterial binding required a minimum of 16 residues. The ability of a given heparin fraction to inhibit binding to Vero cells was strongly predictive of its ability to inhibit hemagglutination, suggesting that hemagglutination reflects the capacity of B. burgdorferi to bind to GAGs.

Animals↗

Depolymerization of heparin by complexed ferrous ions.

Treatment of porcine heparin with the ferrous-EDTA complex and ascorbic acid for 24 h at 37 degrees C results in the degradation of most of the glycosaminoglycan to smaller fragments. About 65% of the products comprise oligosaccharides composed of less than 30 sugar units. The extent of depolymerization is decreased significantly if ascorbate or EDTA is not included in the reaction mixture. Gel filtration of the reaction products yielded fractions with narrow chain length ranges. The sulfate content of the fractions and their electrophoretic mobilities on cellulose acetate indicate that the components have equivalent charge densities. Depolymerization products with 20 or more sugar units retain significant anticoagulant potencies as measured by their effect in accelerating the neutralization of factor Xa by antithrombin.

Animals↗

Effect of inhaled triamcinolone on bronchial hyperreactivity and airways obstruction in asthma.

We measured changes in methacholine bronchial hyperreactivity and airways obstruction in 37 asthmatics treated with inhaled triamcinolone for 6 weeks. All received regular bronchodilator therapy but not steroids or cromolyn. Initial studies included spirometry and the provocative concentration of methacholine required to decrease the FEV1 by 20% (PC20). Patients were randomized into two groups: those given inhaled triamcinolone, 200 micrograms four times daily (T) by metered dose inhaler, and those given a placebo inhaler (P). Daily AM and PM peak flow measurements were recorded, while PC20 and pulmonary function tests were obtained at 3 and 6 weeks. Change in canister weight was used to determine treatment compliance. The PC20 of T increased from a baseline 1.00 mg/mL to 2.90 mg/mL at 6 weeks, whereas in P it decreased from 1.15 mg/mL to 1.05 mg/mL. Percent change in PC20 (delta PC20) for each patient was defined as: [(PC20(week 6)--PC20(baseline]/PC20 (baseline)] X 100. At 6 weeks, this was 290% in T versus 65% in P (P less than .05). Likewise, at 6 weeks T was significantly greater than P with respect to: delta FEV1 (4.1% versus -3.8%, P less than .05) and delta FEF25-75% (20.3% versus -5.6%, P less than .01). Patients were further separated into higher and lower complier subgroups. In T, higher compliers showed more improvement at 6 weeks than lower compliers in: delta PC20 (533.3 versus 67.8%, P less than .05), delta FEV1 (8.7 versus -1.7%, P less than .01), and delta FEF25-75% (31.9 versus 1.1%, P less than .01). These data suggest that triamcinolone improves bronchial hyperreactivity as well as airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

Captopril-induced hypersensitivity lung disease. An immune-complex-mediated phenomenon.

Captopril has not yet been included in the list of drugs causing hypersensitivity lung disease. We report a patient with hypertension, congestive heart failure, and chronic renal failure who, when rechallenged with captopril, developed upper lung field infiltrates associated with productive cough and striking peripheral eosinophilia. Gallium scan, transbronchial biopsy histologic findings, and direct immunofluorescent study were consistent with an immune-complex-mediated hypersensitivity reaction. There was no other etiology discovered for the patient's eosinophilia, nor was there evidence for an infectious etiology to explain his presentation.

Aged↗

Preparation and characterization of NH2-terminal fibrinogen B beta fragments from N-DSK of human fibrinogen.

In order to investigate the early release of NH2-terminal plasmic fragments from the B beta chain of fibrinogen, substantial quantities of B beta 1-42 and B beta 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and B beta 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. B beta 1-42 and B beta 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of B beta 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.

Amino Acid Sequence↗

Applications of high-performance liquid chromatography to the characterization of the interactions of heparin with antithrombin III and thrombin.

A rapid method for differentiating active heparin from inactive components by high-performance liquid chromatography is described. Additionally, the procedure allows for the distinction of heparin fractions with different molecular weights. The methodologies were extended to investigations on the effects of heparin in the interaction between thrombin and antithrombin III. The product formed in the presence of heparin has a characteristic retention time that is ascribed to the binding of heparin to the protein-protein complex.

Animals↗

Adult respiratory distress syndrome in Rocky Mountain spotted fever.

A culture-proved case of Rocky Mountain spotted fever is described in which the typical findings of the adult respiratory distress syndrome developed. Rocky Mountain spotted fever should be added to the list of conditions associated with the adult respiratory distress syndrome. This case also illustrates the difficulties in distinguishing Rocky Mountain spotted fever from atypical measles.

Adolescent↗

Pulmonary function studies in patients with prolapse of the mitral valve.

We studied the pulmonary function and chest x-ray films of 20 nonsmokers with idiopathic prolapse of the mitral valve. Forty-five percent of these patients complained of dyspnea. Of the 16 chest films reviewed, 44 percent had radiographic evidence of pectus excavatum and 25 percent thoracic scoliosis. The most common pulmonary function abnormalities were increased residual volume (63 percent) and a reduced steady state diffusing capacity (50 percent of patients). There was no relationship between the presence of dyspnea and either chest wall deformity of abnormality of pulmonary function. These pulmonary function abnormalities may reflect a pulmonary parenchymal disorder possibly secondary to a connective tissue abnormality in the lung.

Adolescent↗