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Biomedical subjects

B Harrington

Publications and source records attributed to B Harrington.

31 records · Page 2Linked to original sources
PubMed1987

Evidence for diminished inhibitory neuromuscular transmission in distal small intestine.

The influence of myenteric nerves on duodenal muscle contraction and relaxation was examined in vitro and compared with muscle responses from the ileum. Proximal and distal rat small intestine was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimal lengths and subjected to electrical field stimulation (0.1-1.0 msec pulse duration, 30-300 mA, 2-26 Hz) in the presence of Krebs' solution and Krebs' plus atropine, 10(-6) M. Field stimulation produced contraction responses that were inhibited by atropine and relaxation responses that were augmented by atropine. Muscarinic blockade abolished completely contraction in circular muscle, but atropine-resistant contractions persisted in the longitudinal strips. Proximal muscle showed significantly greater relaxation responses compared to distal muscle (P less than .05) at nearly all parameters of pulse duration, current and frequency. Contraction and relaxation amplitudes were significantly greater in longitudinal than respective circular muscle (P less than .05) at either site in the intestine. Thus, not only do the two muscle layers differ in their respective nerve supplies, but inhibitory neuromuscular transmission appears to have a greater influence in proximal than distal intestine.

Animals↗
PubMed1986

Evidence for abnormal cholinergic neuromuscular transmission in diabetic rat small intestine.

Proximal and distal rat small intestine from control, diabetic, and insulin-treated diabetic rats was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, while those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimum lengths and subjected to electrical field stimulation (0.1-1.0-ms pulse duration, 30-270 mA, 1-26 Hz) in the presence of Krebs' solution and Krebs' solution plus 10(-6) M atropine. Field stimulation produced atropine-sensitive and atropine-resistant contractions in all strips. Significant differences among the three groups were found in the amplitudes of atropine-sensitive contractions in strips from distal longitudinal muscle. Controls showed the highest amplitude contractions and diabetics the lowest, whereas the insulin-treated diabetics showed contractions intermediate in amplitude. No significant differences were noted among the atropine-resistant contractions. Field stimulation delivered at pulse durations of 5.0 and 50.0 ms in the presence of neural blockade with tetrodotoxin (5 X 10(-6) M) produced similar contraction amplitudes among the three groups. These results suggest that streptozotocin-induced diabetes mellitus is associated with defective cholinergic neuromuscular transmission in the myenteric plexus of the distal small intestine. Insulin therapy seems to improve the abnormality.

Animals↗
PubMed1985

Effect of cholinergic agonists on muscle from rodent proximal and distal small intestine.

Proximal and distal rat small intestine was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90 degrees to that axis were called circular strips. Stress in circular and longitudinal muscle strips was measured continuously as they were superfused with acetylcholine, carbamylcholine, methacholine, bethanechol, or physostigmine. Resting stress during stretch, acetylcholine-stimulated active stress, and total stress were determined. Proximal circular muscle was five times as sensitive to acetylcholine as distal circular muscle (p less than 0.05); proximal longitudinal muscle was 2.8 times as sensitive to bethanechol as distal muscle (p less than 0.05). Resting, active, and total stress were similar in proximal and distal muscle, but circular muscle showed nearly twice the resting stress of longitudinal muscle at either proximal or distal sites (p less than 0.05). Physostigmine (10(-6) M) increased acetylcholine-stimulated active stress in proximal and distal circular muscle by 29% and 70%, respectively (p less than 0.05), but not in longitudinal muscle (p greater than 0.05). This difference between proximal and distal circular muscle (41%) was also significant (p less than 0.05). Thus, the proximal and distal muscle of the rat small intestine differs in its sensitivity to various cholinergic agonists, but not in its length-stress properties.

Acetylcholine↗
PubMed1982

The effects of the transcendental meditation and TM-Sidhi program on the aging process.

To evaluate the effects of the Transcendental Meditation (TM) and TM-Sidhi program on the aging process, a standardized test of biological aging, utilizing auditory threshold, near point vision, and systolic blood pressure, was given to a cross-sectional group (N = 84) with a mean age of 53 years. There were 11 controls, 33 short-term TM and TM-Sidhi participants, and 40 long-term participants. The mean biological age of the controls was 2.2 years younger than for the general population; of the short-term TM subjects, 5.0 years younger; of the long-term TM subjects, 12.0 years younger. The difference between the groups was significant covarying for a diet factor. Also, there was a significant correlation between length of time practicing the TM program and biological age (r = -0.46). Together with numerous physiological and psychological studies conducted on the TM and TM-Sidhi program, this study suggests that the TM program may affect certain neural mechanisms which in turn influence age correlated physiological variables.

Adult↗
PubMed1976

Sex differences in alcoholics: a comparison of male and femal alcoholics' self and spouse perceptions.

Self-perceptions of male and female alcoholics and the perception of them by their respective spouses were investigated in an attempt to study sex differences in alcoholics. The subjects were 20 male and 20 female hospitalized alcoholics and their spouses. Subjects were administered a modified Katz Adjustment Scale and the NIMH Mood Scale applied both to states of sobriety and intoxication. The results indicated that the female alcoholic is more likely to characterized by her spouse as guilty and depressed both in states of sobriety and intoxication than is the male alcoholic. The therapeutic implications of these and other findings are discussed.

Adult↗
PubMedDate not supplied

Pharmacokinetics of an osmotically controlled delivery indomethacin preparation in normal volunteers.

Indomethacin is still used commonly for the treatment of rheumatic diseases but is associated with side effects, particularly headache, in a number of patients. A controlled or sustained release formulation of indomethacin might provide lower peak plasma levels and thus reduce side effects while still maintaining adequate plasma levels to control pain and inflammation. In this single dose crossover study, normal volunteers received the new formulation of indomethacin (Indocid GITS 6/85) fasting or with a standard meal, indomethacin 75 mg with a standard meal or indomethacin 25 mg three times daily with a standard meal. Plasma concentration data showed that peak plasma levels were reduced but the area under the plasma concentration curve was not significantly different between the four treatments.

Adult↗