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Biomedical subjects

M Atkinson

Publications and source records attributed to M Atkinson.

138 records · Page 8Linked to original sources
PubMedDate not supplied

Palliative therapy of malignant esophageal stricture with the bipolar tumor probe and prosthetic tube.

Patients with malignant esophageal stricture and dysphagia were prospectively randomized to receive palliative therapy with the bipolar tumor probe (17) or prosthetic tube insertion (13). Both treatments gave good relief of dysphagia compared with pretreatment values on a dysphagia score, the results being statistically significant (p less than 0.005). However, there was no difference in the improvement achieved by one method compared with the other. The tumor probe was not difficult to use and complication rates were comparable. In the Atkinson tube group, two patients developed complications related to the position of the prosthesis and in three others food blocked the tube. Treatment with the tumor probe needed repeating at intervals (median, 28 days; range, 2 to 86 days) in all but four individuals to maintain palliation, with each patient needing a median of two treatments (range, 1 to 8). The probe may have advantages in very high esophageal lesions and may facilitate the treatment of tumor overgrowth or undergrowth of a tube. The prosthetic tube may give long-lasting relief of dysphagia and remains the treatment of choice for bronchopulmonary fistulas.

Adenocarcinoma↗
PubMedDate not supplied

Selective fetal malnutrition: effect of acute and chronic ethanol exposure upon rat placental Na,K-ATPase activity.

Intrauterine growth retardation (IUGR) is characteristic of the fetal alcohol syndrome (FAS). This IUGR is partly due to the toxic effect of ethanol upon placental function, including amino acid transport. Amino acid transport is dependent, in part, upon Na,K-ATPase; therefore, plasma membrane activity of Na,K-ATPase was measured in rat placentas following acute or chronic ethanol exposure. Acute (A) animals were chow fed and gavaged with ethanol on day 20 of gestation and killed 2 hr later; controls (A-C) received sucrose. Binge (B) animals were gavaged on gestation days 18 and 19; controls (B-C) received sucrose. Chronic animals were fed ethanol in a liquid diet containing 2% (CHR-2%) or 6% (CHR-6%) ethanol by volume and killed on day 20. Controls (CHR-2%-C or CHR-6%-C) were isocalorically pair fed. Maternal blood ethanol levels were 197.1 +/- 29.7 mg/dl (mean +/- SE) for A dams and 128.2 +/- 15.2 for B (drawn at time of death); 12.6 +/- 2.2 for CHR-2% and 195.0 +/- 26.0 for CHR-6% (drawn weekly and at time of death). Placental weight was increased and fetal weight decreased in the CHR-6% animals. A, B, and CHR-2% placental and fetal weights were unaffected. Na,K-ATPase specific activity was increased in B placentas: B = 134.7 +/- 16.5 versus B-C = 50.0 +/- 7.4 nmol of Pi/mg of protein/min (p less than 0.01). Conversely, CHR-6% treatment diminished enzyme activity: CHR-6% = 37.0 +/- 4.5 versus CHR-6%-C = 58.5 +/- 4.4 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Autorhythmometry in manic-depressives.

Three manic-depressives were studied longitudinally. Several times a day, the patients measured and recorded their mood, vigor, oral temperature, finger counting, blood pressure, pulse rate, and urine volume. Then the acrophases of their circadian rhythms were computed by a least-squares fit. These patients displayed rhythm phases that were grossly abnormal. Systematic acrophase changes over time supported the hypothesis that manic-depressives have circadian rhythms that free-run faster than one cycle per 24 hrs. Lithium appeared to slow these rhythms and help the environmental synchronizer force physiological functions to coordinate better with the usual 24-h environmental cycles.

17-Hydroxycorticosteroids↗
PubMedDate not supplied

In vitro low frequency electromagnetic field effect on fast axonal transport.

The objective of this study was to evaluate the effects of a low frequency electromagnetic field on fast axonal transport for future neuroprosthetic applications. Changes in speeds and densities of retrograde fast organelle transport in rat sciatic nerve preparations were measured in vitro upon exposure to 15 and 50 Hz pulsed magnetic fields with peak intensities of 4.4 and 8.8 mT. Maximum current density of the induced eddy current was calculated to be about 40 microA/cm2. Video enhanced differential interference contrast microscopy was used to record axons supporting active organelle transport. Strong effects were observed in myelinated axons (cessation of transport in up to 10 min). Such effects may eventually be used as part of a neuroprosthesis to noninvasively modify or couple to various parts of the nervous system.

Animals↗