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Biomedical subjects

C Swanson

Publications and source records attributed to C Swanson.

72 records · Page 4Linked to original sources
PubMed1987

Chemotherapy of advanced colorectal cancer. A randomized trial of sequential methotrexate and 5-fluorouracil.

Fifty-five patients with advanced colorectal cancer were entered into a randomized controlled clinical trial to evaluate order of administration and sequential methotrexate (MTX) and 5-fluorouracil (5-FU) therapy. Patients were randomized to receive either MTX, 250 mg/m2, followed 1 h later by 5-FU, 600 mg/m2, or 5-FU followed 1 h later by MTX in the same doses. Fifty-four patients were evaluable for response, of whom 15 (28%) achieved objective partial tumor response. There were no significant differences between the two sequences in response rate, time to treatment failure, or survival duration. The results of this study do not indicate a clinically significant difference between the two sequences tested, in which MTX preceded or followed 5-FU by 1 h. Determination of the value of these drugs given sequentially at longer intervals must await appropriate controlled trials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Plasma exchange in chronic inflammatory demyelinating polyradiculoneuropathy.

Plasma exchange has been reported to be efficacious in chronic inflammatory demyelinating polyradiculoneuropathy. We performed a prospective double-blind trial in which patients with static or worsening disease were randomly assigned to plasma exchange (n = 15) or to sham exchange (n = 14) for three weeks. After three weeks, we observed statistically significant differences in combined measurements of nerve conduction (total, motor, proximal, velocity, and amplitude) favoring patients who had received plasma exchange. Improvement to a greater degree than for any patient receiving sham exchange was detected in the neurologic-disability score in five patients (P = 0.025) and in subset scores for weakness and reflex in four patients (P less than 0.057). We conclude that for some patients with chronic inflammatory demyelinating polyradiculoneuropathy, plasma exchange has an ameliorating effect on neurologic dysfunction and nerve conduction, but in others no improvement is observed. Because plasma was replaced with normal serum albumin, a humoral factor or factors may have a role in the neurologic deficit of this disorder.

Chronic Disease↗
PubMed1986

Phase-II study of recombinant alpha 2-interferon in advanced malignant melanoma.

Fifteen patients with metastatic malignant melanoma, including 10 who had not previously received systemic therapy, were treated with recombinant alpha2-interferon (IFN-alpha 2) in a dose of 20 million IU/m2 by 30-min i.v. infusion daily for 5 days each 14 days. Evaluable metastatic sites included lung, subcutaneous tissue, liver, nodes, adrenals, and bone. Subjective toxicity was generally mild to moderate, with fever (38.2-40.2 degrees C), occasional rigors, fatigue, myalgia, headache, and nausea. Objective toxicity included transient neutropenia and elevation of hepatic enzymes, particularly gamma-glutamyl transpeptidase. In 1 of the 10 patients receiving more than one cycle, IFN dosage was reduced because of toxicity, but later reescalated. All patients were evaluated for response. No overall partial or complete responses were observed, but two site responses (lung and subcutaneous tissue) were seen. Median survival from start of IFN treatment was 19 weeks. High doses of IFN were reasonably well tolerated in this study, but the results suggest little activity against malignant melanoma.

Adrenal Gland Neoplasms↗
PubMed1986

Differential induction of ethoxyresorufin-O-deethylase in tissues of the rat placenta.

The placenta of the rat during late gestation is comprised of the yolk sac membranes, labyrinth and basal zone, which are of fetal origin, and the decidua basalis, which is derived maternally. Studies investigated whether the placental monooxygenase activity induced by administration of beta-naphthoflavone (beta-NF) and 3-methylcholanthrene (3-MC) to pregnant rats was localized differentially in these separate portions of the organ. Ethoxyresorufin-O-deethylation (EROD) was measured by fluorometric assay in homogenates of the respective placental tissues and of intact fetuses. EROD was very low or undetectable in feto-placental homogenates from untreated control animals. The administration of beta-NF and 3-MC increased EROD activity 50-fold over control in labyrinth and fetal homogenates, 10- to 15-fold in decidua, 8- to 20-fold in fetal membranes and 8-fold in basal zone preparations. The apparent Km value for ethoxyresorufin was significantly lower than control for EROD in labyrinth preparations from both beta-NF- and 3-MC-treated animals. Enzyme activity in labyrinth homogenates was maximally induced by 3-MC treatment for 1 to 3 days. In contrast, EROD activity was maximal after 1 to 2 days beta-NF administration, but declined markedly with longer duration of treatments. Subsequent studies compared the in vitro effects of alpha-naphthoflavone (alpha-NF) and beta-NF on induced EROD in feto-placental homogenates. The two benzoflavones were found to be equipotent as inhibitors with IC50 values less than 1 microM for labyrinth, maternal liver and fetal preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Combination therapy with methotrexate and 5-fluorouracil: a prospective randomized clinical trial of order of administration.

Because of biochemical and tissue culture evidence casting doubt on the physiologic relevance of reported synergy afforded by sequential administration of methotrexate (MTX) followed by 5-fluorouracil (5-FU), a randomized controlled clinical trial was conducted in 108 patients with advanced cancer, including 70 with squamous cell carcinoma (SCC) of the head and neck, nine with SCC of other primary sites, 24 with colorectal, and five with gastric adenocarcinomas. Patients were randomized to receive weekly therapy consisting of MTX followed one hour later by 5-FU, or 5-FU followed one hour later by MTX. There was a trend to higher tumor response rates in patients treated with MTX before 5-FU (45% v 33% overall; 65% v 39% in patients with previously untreated head and neck cancer), but these differences were not significant, either by chi-square test or by multivariate stepwise logistic regression. The trend in survival favoring the reverse sequence of 5-FU before MTX was not significant in univariate analyses. Stepwise multivariate Cox model analysis showed that Eastern Cooperative Oncology Group performance status at study entry was the major prognostic factor for survival (P less than 0.001), but among the 70 patients with head and neck cancer, the sequence of drug administration was the only other significant prognostic factor for survival, and favored the sequence of 5-FU followed by MTX (P less than 0.025).

Adenocarcinoma↗
PubMed1983

Experimental Pseudomonas aeruginosa ulcerative keratitis model in the dog.

Primary Pseudomonas aeruginosa ulcerative keratitis and accompanying secondary ocular disease were induced bilaterally in 12 of 12 dogs subjected to corneal trephination and intrastromal inoculation. Successful experimental infection was based on recovery of viable Pseudomonas organisms from the lesions, as well as gross and biomicroscopic appearance of the corneas.

Animals↗
PubMed1982

The Mayo Clinic experience with plasma exchange in chronic inflammatory-demyelinating polyneuropathy (CIDP).

Fourteen patients with static or progressive CIDP with a neurologic disability score (NDS) greater than or equal to 50 were entered into a double-blind, stratified, 3-week trial of twice-weekly plasma exchange or sham plasma exchange. The end-points evaluated included the NDS, computer assisted sensory examination of the foot, and various attributes of nerve conduction of motor and sensory fibers of limb nerves. Of the 7 patients receiving plasma exchange, 4 improved by more than 10 points on the NDS (45, 32, 11, and 24 points) while 3 remained unchanged (2, -2, and -3 points). One patient, who did not appear to respond to either sham or plasma exchange, improved (100 points) with a 3 month alternate day course of prednisone. Of the 7 patients on sham exchange, 3 improved by more than 10 points (26, 15, and 16), 3 remained unchanged (-5, 4, and 8) and 1 was not able to complete the study due to cardiac tamponade. This preliminary trial will end with acquisition of 30 patients. It is too early to draw any conclusion from these studies other than that the double-blind study employed here is feasible and should provide information on the efficacy of plasma exchange in CIDP if its effect is prompt and large. The improvement which may be seen in the sham group appears to suggest that studies of efficacy require a double-blind design.

Adult↗
PubMed1980

Long latency components of the visually evoked potential in man: effects of aging.

Visual stimuli were used to elicit event related potential (ERPs) from frontal, central, and parietal midline scalp of ten right-handed male subjects in each of five groups (mean ages 28, 47, 63, 72, and 79 years). Stimuli consisted of 35 mm slides in three categories: 80% background; 10% target; and 10% colorful novel slides. Amplitude and latency of four ERP components, N1, P2, N2 and P3 were examined with three-way analysis of variance. Significant differences were found among age groups, stimulus categories and scalp locations. Although ERP component amplitudes were minimally affected by age, two waves, N2 and P3, showed reliable age-related changes in latency with latencies of both being prolonged in older subjects. Advancing age was associated with an acceleration of P3 slowing. Latency increased from 0.8 msec per year between ages 28 and 63 to 1.6 msec per year between ages 63 and 79. An effort was made to relate these results to a neurophysiological model involving the possible neural mechanisms of the P3 component.

Adult↗
PubMedDate not supplied

Orthodromic reciprocating tachycardia and heart failure in a dog with a concealed posteroseptal accessory pathway.

A 4-month-old male Labrador Retriever was presented for recurrent bouts of pulmonary edema associated with tachycardia. Initial physical examination and echocardiography were unremarkable, and the electrocardiogram revealed only an intraventricular conduction disturbance. Subsequent recordings showed paroxysmal supraventricular tachycardia (SVT) (340 beats/min), which consistently produced pulmonary edema. The supraventricular tachycardia was unresponsive to adenosine, esmolol, and propranolol; was variable and transiently responsive to various vagal maneuvers and precordial thumps; and was always responsive to IV diltiazem. Multiple life-threatening episodes of SVT occurred, however, despite the chronic administration of oral diltiazem, propranolol, and procainamide. Diastolic cardiac dysfunction was documented by Doppler echocardiography and was thought to contribute to the development of pulmonary edema. A subsequent electrophysiologic study confirmed the presence of an atrioventricular posteroseptal accessory pathway that participated in orthodromic reciprocating tachycardia. This pathway was determined to conduct only in the retrograde direction ("concealed accessory pathway"). Intraoperative IV procainamide titration terminated the arrhythmia, which could not be reinduced when procainamide blood concentration approximated 20 micrograms/dL. Increasing the oral procainamide dose to achieve such plasma concentrations was successful in eliminating orthodromic reciprocating tachycardia, preventing heart failure, and returning Doppler indices of diastolic function to normal.

Animals↗
PubMedDate not supplied

From Machiavelli to Ms: differences in male-female power styles.

While the concept of power has always been a concern to students of political science and public administration, it has been examined only peripherally in the last few years. Recent work by McClelland has indicated that power may be a very important variable in explaining managerial behavior and organizational effectiveness. Starting with a definition of power provided by McClelland, this paper develops a conceptual framework for analyzing power-related behavior in an organizational setting. The framework is then applied to a problem area of particular interest to the authors--the question of whether or not women managers can be expected to behave differently than their male counterparts because of possible differences in their orientations toward power. We conclude that differences in power needs will not impede the effectiveness of female managers, but women may be at a disadvantage in the work environment due to possible differences in the way they express these needs.

Administrative Personnel↗
PubMedDate not supplied

Assessment of long-term (1 year) graft survival and metabolic and hormonal changes after intrasplenic canine pancreatic microfragment transplantation.

Few data have been published so far on the long-term metabolic and endocrine consequences of intrasplenic islet autografts in dogs and the available information mainly deals with glucose response and, more rarely, insulin secretion during intravenous glucose tolerance tests. The effect of islet transplantation on glucagon levels has never been reported. In this study we measured glucose, insulin, total glucagon, and pancreatic glucagon in dogs before and after (up to 1 year) intrasplenic islet autografts. Pancreata were retrieved from 21 adult dogs and the islets were isolated by collagenase digestion. The endocrine tissue was transplanted into the spleen by direct pulp injection. Autografts resulted in normoglycaemia in 19 out of 21 dogs (90%). Among the successfully transplanted dogs, the percentage of functioning grafts was 71% at 1 year. The metabolic and hormonal results of the follow-up showed that fasting glucose and insulin concentrations did not differ significantly before and after transplantation. However, glucose tolerance and insulin secretion on intravenous glucose tolerance testing were significantly reduced in transplanted animals. Fasting total and pancreatic glucagon, and their integrated releases during the test did not change significantly after islet transplantation. These results demonstrate that: 1) long-term function of intrasplenic canine islet autografts can be achieved in high percentages; 2) autotransplanted animals have normal or near normal fasting glucose and insulin levels, but reduced glucose disappearance and insulin secretion on intravenous glucose tolerance tests; 3) normal glucagon secretion is a feature of successful islet grafts.

Animals↗