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Biomedical subjects

L Lawson

Publications and source records attributed to L Lawson.

At least 55 records · Page 3Linked to original sources
PubMed1988

Effects of nonsteroidal antiinflammatory drugs on renal function in sickle cell anemia.

Renal hemodynamics and solute and water handling were evaluated in 19 sickle cell patients and 8 matched normal subjects during water diuresis, before and after acute oral administration of a nonsteroidal antiinflammatory drug (NSAID). Baseline GFR and RPF were higher in the patients compared to the normals. In contrast to normals, indomethacin and sulindac induced a 16% and 14% decrease in GFR, respectively. Indomethacin resulted in a slight increase in UOsm in normals, but a substantially greater rise in the patients. Following indomethacin a greater fall in FENa, fractional solute delivery to the diluting segment of the nephron [(CH2O + CNa + K)/GFR], fractional solute reabsorption in the diluting segment [CH2O/GFR] and the fraction of distally delivered solute reabsorbed [CH2O/(CH2O + CNa + K)] was observed in the sickle cell patients than in the normal subjects. A similar trend, but of significantly lesser magnitude than that induced by indomethacin, was observed following sulindac in the sickle cell patient. The data imply that the supranormal GFR observed in the sickle cell patients was prostaglandin-mediated. The effects of NSAID's on renal solute and water handling in the sickle cell patients are compatible with a prostaglandin-dependent decreased salt reabsorption in the medullary thick ascending limb of Henle, together with a hyperfunctioning proximal tubule. The data also imply an additional indomethacin-sensitive antinatriuretic effect in the diluting segment in these patients. Moreover, the results suggest that in sickle cell anemia sulindac may not have a "renal sparing" advantage over other NSAID's.

Adolescent↗
PubMed1988

Decreased heart rate variability in significant cardiac events.

The heart rate variability (HRV) of 82 patients exhibiting sinus rhythm and admitted for possible myocardial infarction (MI) was evaluated. Using a simple information entropy measure to quantify the HRV, patients subsequently diagnosed with MI or experiencing significant dysrhythmia (n = 35) exhibited less entropy (0.28 +/- 0.15) within the first 24 h after admission than those patients (n = 45) with no MI (0.36 +/- 0.14; p less than .01). Although correlations between entropy and age and heart rate (HR) were significant (p less than .01), the additional explained variance was minimal. The groups were compared for sex, age, mean HR, past medical history and medications taken and were found to be statistically similar. In our patients without significant dysrhythmias on admission, HRV appeared to be an index for significant cardiac events, and thus may prove to be a useful tool in clinical situations where other objective decision criteria are lacking.

Adult↗
PubMed1987

The effect of a structured education program on knowledge and psychomotor skills of patients using beclomethasone dipropionate aerosol for steroid dependent asthma.

The purpose of the study was to evaluate the efficacy of a structured education program on knowledge and psychomotor skills of subjects using inhaled beclomethasone dipropionate. The sample was comprised of 26 male outpatients with a mean age of sixty years (range 49-69 yrs) and mean educational level of 11 years (range 7-18 yrs). Subjects were tested to assess knowledge of drug action, self-administration, and side effects. Skill in self-administration was assessed by two independent raters who were blind to group assignment. Then, patients were randomly assigned to an experimental group (n = 13), who received a structured educational program, or a control group (n = 13), who received no structured educational interventions. Patients were retested four weeks after randomization. Subjects in the experimental and control groups did not differ significantly with respect to their initial mean knowledge and performance scores. The post-test mean knowledge score was significantly higher when compared to initial score for each group. Mean knowledge score at post-test did not differ significantly between groups. However, when comparing post-test performance scores to initial scores the experimental group had a significantly greater increase in mean score than the control group. It is concluded that a structured patient education program is an effective method for improving the psychomotor skills necessary for proper use of beclomethasone dipropionate aerosol.

Aerosols↗
PubMed1987

An elderly man with bilateral lung disease.

A 60-year-old man with a past history of sprue was admitted with cough and dyspnea and was found to have diffuse, bilateral interstitial lung disease with Kerley-B lines and pleural effusions. An open lung biopsy revealed a diffuse lymphatic infiltration of the interstitium with lymphocytes which were judged to be neoplastic rather than inflammatory. Thus non-Hodgkin's lymphoma was diagnosed. A good response to therapy was obtained.

Humans↗
PubMed1986

Malignant mesothelioma caused by childhood exposure to long-fiber low aspect ratio tremolite.

A 41-year-old man was found to have a malignant mesothelioma of the pleura. During childhood in Corsica, he had been exposed at home to chrysotile ore from the Canari mine. Analysis of lung mineral content revealed background levels of chrysotile but an elevated level of tremolite and actinolite asbestos. The latter had a geometric mean length of 3.7 microns, a value considerably longer than we have found for tremolite and actinolite from Quebec chrysotile miners but roughly the same as the mean length of amosite and crocidolite in workers with occupational amphibole exposure. No tremolite or actinolite fibers of length greater than 8 microns microns and width less than 0.25 micron were observed. The mean aspect ratio of the tremolite and actinolite fibers was 7, a value similar to that found in chrysotile miners with mesothelioma but considerably less than the mean aspect ratio of amosite and crocidolite from those with occupational exposure. These data suggest that long-fiber tremolite is a potential mesothelial carcinogen in humans, and that fiber length is more important than fiber aspect ratio in this regard.

Adult↗
PubMed1986

Chronic fatigue.

Explore the source record for details and available documents.

Anxiety↗
PubMed1983

The structure and function of the pulmonary vasculature in mild chronic obstructive pulmonary disease. The effect of oxygen and exercise.

The structure and function of the pulmonary circulation was investigated in 17 patients requiring pulmonary resection. All 17 performed pulmonary function tests and 13 underwent right heart catheterization preoperatively. The surgical specimens of the lung were analyzed with respect to the severity of the emphysema, the severity of the airways disease, and the hypertensive changes in the small pulmonary arteries and arterioles. The data show that pulmonary artery (Ppa) and pulmonary artery wedge (Ppaw) pressures and cardiac output were normal at rest. However, patients with more severe disease showed greater increases in Ppa and Ppaw with exercise than did patients with minimal or no disease. Oxygen breathing had no effect at rest but lowered Ppa and Ppaw during exercise in the patients with more severe disease. Histologic studies showed that greater degrees of emphysema and small airways disease were associated with hypertensive changes in the pulmonary vasculature. We conclude that patients with moderate obstructive lung disease have elevated pulmonary vascular pressures during exercise and structural changes in the pulmonary arteries consistent with pulmonary hypertension when compared with patients with minimal or no disease. Although there are several possible explanations for the increased vascular pressures seen with exercise, we favor gas trapping leading to increased alveolar and pleural pressures, with oxygen breathing preventing this response by shortening the time constants of the peripheral lung units.

Aged↗
PubMed1983

Transsphenoidal microsurgery of pituitary macroadenomas with long-term follow-up results.

The authors have reported on 108 patients with pituitary macroadenomas (measuring 2 cm in at least one diameter) who underwent 117 transsphenoidal operations and five craniotomies, and were followed for periods ranging from 6 months to 14 years. Vision improved in 90% of the patients. Gross total tumor removal with no evidence of residual tumor tissue demonstrable on the postoperative computerized tomography scan was accomplished in 41% of cases. However, gross total tumor removal is not synonymous with complete tumor removal. Endocrine cure was possible in 25% of prolactin-secreting and 20% of growth hormone-secreting adenomas. The incidence of recurrence was 12%, with the majority occurring from 4 to 8 years postoperatively. Both the tumors with suprasellar extension of more than 2 cm and the hard fibrotic tumors had a higher recurrence rate. Postoperative administration of radiation therapy has been associated with a significantly lower recurrence rate than when this therapy was withheld. Transsphenoidal surgery of pituitary macroadenomas confined to the extra-arachnoid space is associated with a relatively small number of complications. The operative technique used in this series is described.

Adenoma↗
PubMed1983

Selective immunosuppression resulting from exposure to the carcinogenic congener of benzopyrene in B6C3F1 mice.

B6C3F1 mice were exposed to two congeners of benzopyrene, either the carcinogen benzo(a)pyrene (B(a)P) or the non-carcinogen benzo(e)pyrene (B(e)P. Exposure of mice to B(a)P resulted in a reduced number of IgM and IgG antibody plaque forming cells (PFC) to the T-dependent (TD) antigen SRBC and IgM PFC's to the T-independent (TI) antigen LPS. The IgM response to hapten conjugated TI antigens was examined using TNP-LPS for reactivity of less mature B cells (B1) and TNP-Ficoll for more mature B cells (B2). Exposure to B(a)P severely depressed the TNP-Ficoll PFC response by up to 77% without altering the TNP-LPS response. These data indicated that exposure to B(a)P alters differentiation and antibody production in mature B cells to both TD and B2 TI antigens. No change in PFC was observed following exposure to B(e)P. Mishell-Dutton co-cultures confirmed that B cells were affected and that T helper cells or suppressor Mphi were not involved. Parameters of cell-mediated immunocompetence including delayed cutaneous hypersensitivity to KLH, allograft or tumour cell rejection and susceptibility to Listeria monocytogens were unaltered in B(a)P treated mice.

Animals↗