Search PubMed⌕ Search

Biomedical subjects

P M Stevens

Publications and source records attributed to P M Stevens.

At least 37 records · Page 2Linked to original sources
PubMed1980

Plasma levels and urinary excretion of orally administered propantheline bromide in man.

After a single oral dose of 30 or 60 mg of propantheline bromide peak plasma levels of the drug were reached within 2 h in six healthy men. Mean peak plasma concentrations were 20.6 and 53.1 ng/ml after 30 mg and 60 mg respectively. The mean apparent absorption and elimination half-lives after 30 mg dose were 0.22 and 1.57 h respectively, and similar half-lives were found at the higher dose level. There was a dose related change in plasma levels and AUCinfinity of the drug, and some 3% to 4% of the administered dose of propantheline bromide was excreted unchanged in urine at each dose level. Comparison of the plasma levels and urinary excretion of the drug with those seen after i.v. administration in an earlier study indicated an apparently low systemic availability of orally administered propantheline bromide. There was tentative evidence of a qualitative relationship between the oral dose administered, plasma concentrations and the effects of propantheline bromide on salivary excretion.

Administration, Oral↗
PubMed1980

A long-term review of shelf arthroplasty.

Shelf arthroplasty is briefly reviewed in historical perspective and the results in 45 hips (39 patients) which had undergone this procedure at the Royal Children's Hospital are presented. The majority of these patients were adolescents who had previously been treated for congenital dislocation or subluxation of the hip. The indications for operation and the operative technique are discussed. Clinical examination was carried out upon 33 of the 39 patients at an average of 11 years after operation. The results suggested that where pain had been an indication for operation almost 80 percent of the hips remained relatively free of symptoms at the time of follow-up and in those patients where acetabular dysplasia had been an indication, the coverage remained good and pain had not appeared. It is concluded that the shelf operation is useful for dealing with both pain and dysplasia in the adolescent.

Adolescent↗
PubMed1980

First pass radionuclide assessment of right and left ventricular ejection fraction in chronic pulmonary disease. Effect of oxygen upon exercise response.

Right and left ventricular ejection fraction (RVEF; LVEF) were determined in patients with severe chronic pulmonary disease (mean +/- SEM [FEV1 percent predicted 36 +/- 3%; PaO2: 64 +/- 3 mm Hg]), utilizing first pass radionuclide angiocardiography. RVEF and LVEF were measured at rest and again during upright bicycle exercise while patients breathed room air, and again during low flow oxygen (O2) administration. Mean RVEF was abnormal (less than 45%) at rest and did not increase with exercise while subjects breathed room air (44 +/- 2 percent vs 44 +/- 3 percent, P = ns), but improved significantly during exercise while patients breathed O2 (45 +/- 5 percent vs 51 +/- 3 percent, P less than .05). Breathing room air, RV exercise ejection fraction was abnormal (less than 5 percent increase in absolute RVEF) in 15 of 18 patients, but only 5 of 10 patients were abnormal during O2 administration. LVEF at rest was normal in all subjects. These data suggest: 1) RV exercise ejection fraction is abnormal in most patients with chronic pulmonary disease; 2) while low flow O2 does not alter RV performance at rest, it improves RV exercise ejection fraction in some patients.

Aged↗
PubMed1979

The influence of PEEP on survival of patients in respiratory failure: a retrospective analysis.

Positive end expiratory pressure breathing (PEEP) is used to decrease morbidity and mortality in patients who are hypoxemic despite breathing oxygen in concentrations potentially toxic to their lungs. We reviewed the hospital course of 78 patients whose arterial oxygen tension (PaO2) was less than 70 torr despite a fraction of inspired oxygen (FiO2) of 1.0. Only 60 per cent of these patients were treated with PEEP and their clinical illnesses and severity of cardiopulmonary dysfunction were similar to those in patients not treated with PEEP. PEEP increased the length of survival from 4.2 to 9.2 days (P less than 0.05) whereas over-all survival, defined as hospital discharge, was similar at 31 per cent with and 26 per cent without PEEP. An improvement in PaO2 and decrease in shunt fraction following a trial of PEEP portends a favorable outcome, but its continued use appears to prolong life for a few days without affecting hospital mortality. Survival appears related more to the maintenance of adequate tissue oxygenation as manifested by a high mixed venous oxygen than to improved gas exchange as reflected by an increase in PaO2.

Adult↗
PubMed1979

Preoperative pulmonary function and complications after cardiovascular surgery.

Results of preoperative pulmonary function tests were evaluated in 106 patients who had major thoracic or upper abdominal cardiovascular surgery. These results were related to the occurrence of postoperative complications by comparison of pulmonary function data in patients with an ICU stay of less than 5 days versus patients with an ICU stay of greater than 5 days. However, quantitative analysis of several specific parameters of pulmonary function tests failed to reveal any difference in the incidence of postoperative complications between patients with modest versus severe preoperative dysfunction. The occurrence of atelectasis was related to type of cardiovascular surgical procedure, but not to preoperative pulmonary function tests. Abnormalities on pulmonary function tests were not the major determinants of use of preoperative respiratory therapy, and its use was unrelated to the length of stay postoperatively in the ICU. We conclude that prior to cardiovascular surgery, routine quantitation of clinically apparent pulmonary dysfunction may be of little value in predicting postoperative morbidity and much less important than careful clinical evaluation. When pulmonary function tests are performed in such patients, simple spirometric tests and arterial blood gas levels are adequate.

Aged↗
PubMed1979

Effects of chronic amorphous silica exposure on sequential pulmonary function.

To assess clincial effects of precipitated amorphous silica (PAS), the authors reviewed serial spirograms, respiratory questionnaires, and chest radiographs of 165 workers exposed for a mean of 8.6 years. Monthly exposure was graded on a 1 to 4 scale and a "cumulative exposure index" (CEI) calculated for each worker from the sum of measured exposure. A "mean exposure index" (MEI) was calculated by dividing the CEI by total months exposed. Sputum production and dyspnea were inversely correlated with CEI, while cough and dyspnea correlated with mean pack-years of smoking but not PAS exposure. Linear regression analysis of yearly change of all pulmonary function variables (FVC, FEV1, FEV1/FVC, FEF25-75) showed no correlation with either the dose of PAS (CEI) or total years of exposure. Among 44 workers with a mean exposure time of 18 years (range 10-35 years), yearly decline of FVC and FEV1 were similar to the overall group. Of 143 workers with serial radiographs and exposure to only PAS, none had radiographic pneumoconiosis. Respiratory symptoms in PAS workers correlate with smoking but not with PAS exposure, while serial pulmonary function values and chest radiographs are not adversely affected by long-term exposure.

Adult↗
PubMed1978

Clinical implications of a "nonspecific" transbronchial biopsy.

The diagnostic accuracy of transbronchial biopsy via fiberoptic bronchoscope was reviewed in 127 noncritically ill patients. Biopsy results were analyzed according to whether a "specific" pathologic diagnosis of neoplasm, granuloma or pneumonia, or a "nonspecific" diagnosis of inflammation, fibrosis or normal lung was made. The clinical significance of a "nonspecific" biospy specimen was evaluated by clinical follow-up of at least 12 months (mean 15 months) and by grouping patients according to the type of abnormality found on chest roentgenography. Clinical follow-up was available in 119 of these patients. The over-all "specific" diagnostic yield for biopsy with secretions was 49 per cent, with transbronchial biopsy being the sole means of specific diagnosis in 14 per cent of the patients with a peripheral mass lesion, in 18 per cent of the patients with localized infiltrative processes and in 52 per cent of the patients with diffuse infiltrative processes. In 64 (52 per cent) patients both biopsy specimens and secretions were diagnostically nonspecific. In 16 (77 per cent) patients with peripheral mass lesions but nonspecific biopsy findings and secretions, neoplasm was diagnosed by more invasive procedures. However, 22 (91 per cent) patients with localized and 12 (75 per cent) patients with diffuse infiltrative processes had benign clinical follow-up suggesting that open lung biopsy in such patients should be reserved for patients with obvious clinical or roentgenographic evidence of deterioration.

Biopsy↗
PubMed1978

Radiography, radionuclide imaging, and arthrography in the evaluation of total hip and knee replacement.

Twenty patients with 21 total joint replacements including 17 hips and 4 knees were studied by plain film radiography, radionuclide imaging, and subtraction arthrography to evaluate these procedures for assessing prosthetic complications. Surgery was performed in 14 patients and confirmed loosening of 8 femoral and 7 acetabular hip prosthesis components and 1 femoral and 4 tibial knee prosthesis components. Plain films suggested loosening of only 9 hip components and no knee components. In contrast, radionuclide imaging and subtraction arthrography were considerably more effective in demonstrating loosening as well as other causes of the painful total joint prosthesis.

Hip Joint↗
PubMed1978

Immunoglobulin secreting cells in normal human bronchial lavage fluids.

Immunoglobulin secreting cells were quantitated in the bronchial lavage fluids of 12 normal volunteers and compared with immunoglobulin secreting cells in peripheral blood, by a reverse hemolytic plaque assay. The mean number of cells secreting immunoglobulin (Ig)G in bronchial lavage fluids was 489 per million lymphocytes vs. a mean of 175 IgG secreting cells per million lymphocytes in peripheral blood (P < 0.02). The mean number of IgA secreting cells in bronchial lavage fluids was 633 per million lymphocytes as compared to 100 per million lymphocytes in peripheral blood (P < 0.005). Thus, compared to peripheral blood, cells from the lavage fluids were relatively enriched for both IgG and IgA secreting cells. However, IgA secreting cells were the major class of immunoglobulin secreting cells in bronchial lavage fluids, whereas IgG secreting cells predominated in peripheral blood. The prominence of IgA secreting cells in bronchial lavage fluids was further demonstrated by a mean ratio of IgA/IgG secreting cells in bronchial lavage fluids of 1.26 compared to a ratio in peripheral blood of 0.57 (P < 0.02). Cells secreting IgM were identified in only four of seven bronchial lavage fluid samples studied but in all peripheral blood samples. IgE secreting cells were not present in normal peripheral blood but could be demonstrated in 5 of 11 lavage fluid specimens. Thus, cells actively secreting immunoglobulins can be identified in the lower bronchial-alveolar tree of normal human subjects. Cells secreting IgG, IgA, or IgM may function in local lung defenses against infection; cells secreting IgE may contribute to hypersensitivity reactions in the lung.

Adult↗
PubMed1978

Tibial lengthening.

Tibial lengthening as a means of correcting certain discrepancies in lower limb length has become a well-accepted, though rarely indicated, procedure. Success depends upon knowledgable evaluation of all factors involved in the problem, upon adherence to the indications and prerequisites, and upon strict attention to all details of the operation. Nearly all cases of tibial lengthening are accompanied or followed by problems and/or complications. Problems such as delayed union, inadequate union and failure of union must be anticipated and appropriately coped with. Complications such as fracture through the lengthened area, compartment syndromes, infection, and foot and ankle deformities must be prevented if at all possible, and aggressively treated when they occur. Utilizing the appropriate indications and meticulous technique, one can expect to achieve lengthening of 4--5 cm in nearly all cases. Bone grafting and internal fixation will be required in a significant number of tibial lengthenings in order to achieve strong, solid union. The technique currently employed by the authors utilizes the Anderson percutaneous osteotomy, accompanied by the Wagner apparatus. In critically analyzing the results of 73 personal cases of tibial lengthening, the authors conclude that the procedure is justified in carefully selected patients.

Adolescent↗
PubMed1977

Evaluation of transbronchial biopsy of the lung.

Transbronchial biopsy of the lung through the fiberoptic bronchoscope is becoming a widely utilized clinical diagnostic technic. The authors reviewed the histologic features of 109 consecutive cases. The primary problem is the small size of the pulmonary tissue samples obtained, which is further compounded by an apparent mechanical inability to enter the biopsy forceps into dense nodules of neoplastic tissue. The diagnosis of carcinoma can best be made by examining the periphery of the cancer for microscopic extension into adjacent pulmonary parenchyma; however, multiple levels of the tissue block are needed to find such foci. A second problem reflects the use of transbronchial biopsy in the early clinical evolution of various infectious diseases in which pulmonary tissue may contain organisms without a fully developed inflammatory response, which would ordinarily provide the clue to the infective agent. The latter problem appears in cases of infections by Pneumocystis carinii. Close cooperation between the clinician and the pathologist is particularly important in all of these clinical situations.

Biopsy↗