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Biomedical subjects

D Powers

Publications and source records attributed to D Powers.

At least 37 records · Page 2Linked to original sources
PubMed1992

Pulmonary effects of exposure to fine fibreglass: irregular opacities and small airways obstruction.

OBJECTIVE: Man made mineral fibres imitate asbestos and produce tumours of the pleura in animals. To answer the question, Does prolonged exposure to fibreglass adversely affect pulmonary function or produce radiographic abnormalities in human subjects? we studied workers in a midwestern appliance plant where refrigerator doors and previously entire cabinets were insulated with fibreglass sheeting and loose rotary spun fibreglass. METHODS: Spirometry and lung volumes were measured, respiratory and occupational questionnaires were administered, and chest x-ray films were read for pneumoconiosis using International Labour Office (ILO) 1980 criteria in 284 workers with exposure of 20 years or more. RESULTS: Expiratory flows were reduced including FEV1 (mean 90.3% of predicted (pr), FEF25-75 (85.5% pr), and FEF75-85 (76.2% pr). Forced vital capacity was significantly reduced (92.8% pr) and total lung capacity was significantly increased (109.2% pr). In white male smokers, a group large enough for comparisons, parameters of pulmonary function were reduced further in the presence of irregular opacities. Forty three workers (15.1%) had evidence of pneumoconiosis on chest radiographs: 26 of these (9.1%), had no known exposure to asbestos and 17 (6.0%) had some exposure. The best judgement was that in 36 (13.0%), pulmonary opacities or pleural abnormalities were due to fibreglass. CONCLUSION: Commercial rotary spun fibreglass used for insulating appliances appears to produce human disease that is similar to asbestosis.

Asthma↗
PubMed1988

The influence of carbohydrate structure on the clearance of recombinant tissue-type plasminogen activator.

Modification of the carbohydrate structures of recombinant tissue-type plasminogen activator (rt-PA) can increase or decrease its rate of clearance in rabbits. When rt-PA was treated with sodium periodate to oxidize carbohydrate residues, the rate of clearance was decreased from 9.6 +/- 1.9 ml min-1 kg-1 to 3.5 +/- 0.6 ml min-1 kg-1 (mean +/- SD, n = 5). A similar change in the clearance of rt-PA was introduced by the use of endo-beta-N-acetyl-glucosaminidase H (Endo-H), which selectively removes high mannose asparagine-linked oligosaccharides; the clearance of Endo-H-treated rt-PA was 5.0 +/- 0.5 ml min-1 kg-1. A mutant of rt-PA was produced with an amino acid substitution at position 117 (Asn replaced with Gln) to remove a potential glycosylation site that normally contains a high mannose structure. The clearance of this material was also decreased, similar to the periodate and Endo-H-treated rt-PA. Conversely, when rt-PA was produced in the CHO 15B cell line, which can produce only high mannose oligosaccharide structures on glycoproteins, the clearance was increased by a factor of 1.8. These results demonstrate that the removal of rt-PA from the blood depends significantly upon the nature of its oligosaccharide structures.

Animals↗
PubMed1986

Activation of intrinsic coagulation pathway in pre-eclampsia.

Disseminated intravascular coagulation, thrombocytopenia, consumption of factors VIII and II, and antithrombin deficiency have been previously demonstrated in pre-eclampsia. However, the precise mechanism responsible for initiation of disseminated intravascular coagulation has not been elucidated. The present study documents activation of the intrinsic coagulation pathway in a patient with severe pre-eclampsia. The studies revealed marked reductions of plasma coagulant activities of all intrinsic pathway factors, i.e., XII, XI, IX, and VIII. In addition, the ratio of plasma factor XII activity to antigen concentration was markedly abnormal, and plasma high-molecular-weight kininogen concentration was diminished. It is suggested that activation of the intrinsic coagulation pathway may be operative in the genesis of disseminated intravascular coagulation in pre-eclampsia.

Adult↗
PubMed1985

Rapid detection of venous air embolism by mass spectrometry during bone marrow harvesting.

An episode of venous air embolism occurred in a 13-year-old girl undergoing bone marrow harvest for an autologous bone marrow transplant. The diagnosis was suspected with the sudden appearance of tachycardia and a new heart murmur during inadvertent application of positive pressure to marrow aspiration needles. Decreased carbon dioxide and increased nitrogen content of end-tidal expiratory gases was detected by continuous mass spectrometric monitoring. Cessation of faulty aspiration technique and application of positive end expiratory pressure with 100% oxygen prevented a potentially fatal complication. Venous air embolism may complicate bone marrow harvest. Mass spectrometric monitoring of end-tidal gases is useful for rapid, early detection of this complication.

Adolescent↗
PubMed1984

Winter flounder antifreeze proteins: a multigene family.

The nucleotide sequence of a cDNA clone of winter flounder antifreeze protein was determined by the dideoxynucleotide method. The sequence would predict a protein of 91 amino acids composed of a prepropeptide of 38 amino acids and a mature protein of 53 amino acids, which includes four complete 11-amino acid repeats. This predicted sequence corresponds to an antifreeze protein of intermediate size which is one 11-amino acid repeat longer than the smallest antifreeze proteins found in the serum of winter flounder during the cold season. Southern blot hybridization analysis of winter flounder genomic DNA with radioactive cDNA probes reveals a multigene family of potential antifreeze protein genes. This conclusion is supported by amino acid sequence analysis of several serum antifreeze proteins.

Amino Acid Sequence↗
PubMed1984

Focal renal cortical necrosis associated with zomepirac.

Anaphylactoid shock, disseminated intravascular coagulation, and anuric renal failure requiring dialysis occurred in a patient receiving zomepirac sodium for toothache. Although renal function showed gradual improvement after seven days of anuria, the recovery was slow and incomplete. Renal biopsy three weeks after the onset of renal failure revealed evidence of focal renal cortical necrosis. Association of zomepirac administration with renal cortical necrosis is not known to have been previously demonstrated. This observation adds another dimension to the previously reported renal complications of nonsteroidal anti-inflammatory agents, especially zomepirac. The proportions of lymphocyte subsets, as defined with monoclonal antibodies, and the proliferative response to mitogens were normal. The patient's lymphocytes showed no proliferative response to zomepirac. Serum complement components and immunoglobulin levels were within normal limits, and radioallergosorbent testing gave negative results. The mechanism of anaphylactoid reaction to zomepirac in this case, therefore, remains unclear.

Analgesics↗
PubMed1984

Plasma and urinary catecholamines and their metabolites in chronic renal failure.

The effect of chronic renal failure (CRF) on the plasma concentration and urinary excretion of catecholamines and their metabolites was studied in 14 patients with varying degrees of chronic renal failure who had creatinine clearances of 19 to 77 mL/min. The results were compared with those obtained in a group of age-matched normal controls. Plasma catecholamine concentrations were significantly higher in the CRF patients compared with age-matched normal controls (456.9 +/- 303.1 v 278.5 +/- 81.1 pg/mL). The urinary metanephrine (0.6 +/- 0.6 mg/g creatinine) and vanillylmandelic acid (VMA) (6.6 +/- 4.2 mg/g creatinine) were within the normal range. No significant correlations were found between creatinine clearance and urinary metanephrine and VMA excretion or with the plasma catecholamine concentrations. Our observations indicate that, despite the decrease in creatinine clearance, urinary VMA and metanephrine determinations are valid screening tests for pheochromocytoma in patients with compromised renal function. Plasma catecholamine concentrations, however, show moderate elevation with decreasing renal function.

Adult↗