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Biomedical subjects

P Zimmerman

Publications and source records attributed to P Zimmerman.

9 recordsLinked to original sources
PubMed1991

Lesions of the suprachiasmatic nucleus disrupt circadian locomotor rhythms in the mouse.

Entrained and free-running rhythms of wheel-running activity were recorded in male BALB/cByJ mice with electrolytic lesions of the suprachiasmatic nucleus (SCN), site of a circadian pacemaker in mammals. Complete ablation of the nucleus abolished the circadian locomotor rhythm; in some cases, wheel-running was synchronized by a light-dark cycle, but the phase relationship of this activity to the cycle was often aberrant. Unilateral lesions or those missing the SCN did not eliminate rhythmicity.

Animals↗
PubMed1991

Monitoring asthma.

The authors outline the management of asthma once the 'best lung function' is determined and answer some questions that may arise in general practice during the long-term monitoring of asthmatic patients. The answers represent the opinion of the authors, but are referenced where applicable.

Adult↗
PubMed1990

Circadian timekeeping in BALB/c and C57BL/6 inbred mouse strains.

Circadian rhythms of locomotion (wheel-running activity) in 12 inbred mouse strains were recorded for interstrain differences in tau DD, the endogenous (free-running) period of the circadian pacemaker measured in constant environmental darkness. The results indicate that 1 or more genetic loci influence the value of tau DD, and a large (50 min) difference in mean tau DD between 2 of the strains, BALB/cByJ and C57BL/6J, allowed further characterization of the origins and inheritance of the polymorphic expression of this circadian pacemaker property. The interstrain difference in mean tau DD was associated with an interstrain difference in light-induced shifts of the phase of the free-running locomotor rhythm; the BALB/c strain (with the shorter mean tau DD) displayed relatively fewer advance phase shifts. Neither the history of previous light exposure, albinism, nor elevated circulating testosterone levels could account for the interstrain difference in mean tau DD. The value of tau DD based on the circadian rhythm of drinking activity (with the running wheel removed) was longer than that based on locomotion; this discrepancy was significantly greater and more variable in BALB/c than in C57BL/6 mice, though the interstrain difference in mean tau DD could not be attributed entirely to this effect. Reciprocal F1 hybrids of BALB/c x C57BL/6 matings revealed dominance of the C57BL/6 genotype, no sex linkage, and a significant (but small) maternal effect. Examination of CXB recombinant inbred strains provided no support for the hypothesis of monogenic inheritance. Further study of inherited differences in the BALB/c and C57BL/6 strains may be a useful noninvasive experimental approach for investigation of the neurobiological substrates of circadian rhythmicity.

Animals↗
PubMed1989

Fluoxetine-induced akathisia: clinical and theoretical implications.

Five patients receiving fluoxetine for the treatment of obsessive compulsive disorder or major depression developed akathisia. The typical fluoxetine-induced symptoms of restlessness, constant pacing, purposeless movements of the feet and legs, and marked anxiety were indistinguishable from those of neuroleptic-induced akathisia. Three patients who had experienced neuroleptic-induced akathisia in the past reported that the symptoms of fluoxetine-induced akathisia were identical, although somewhat milder. Akathisia appeared to be a common side effect of fluoxetine and generally responded well to treatment with the beta-adrenergic antagonist propranolol, dose reduction, or both. The authors suggest that fluoxetine-induced akathisia may be caused by serotonergically mediated inhibition of dopaminergic neurotransmission and that the pathophysiology of fluoxetine-induced akathisia and tricyclic antidepressant-induced "jitteriness" may be identical.

Adolescent↗
PubMed1988

Myocardial protection by perfluorochemical infusion during transient ischemia produced by balloon coronary occlusion.

To assess the efficacy of the perfluorochemical Fluosol-DA 20% for myocardial protection during repeated periods of balloon occlusion of the left circumflex coronary artery, 25 anesthetized dogs were randomized to receive either oxygenated perfluorochemical, (Fluosol-DA [F]; n = 10) or oxygenated Ringer's lactate (R; n = 6), at the rate of 30 ml/min, during inflation of the balloon. A control group (C; n = 9) received no infusion. A total of eight inflations were performed, each lasting 90 seconds, followed by an equivalent deflation time. Hemodynamics, ECGs, regional myocardial function, and biochemical parameters were studied. Significant differences were noted in ST segment elevation at 90 seconds of inflation in the F (1.5 mm +/- 0.6), C (3.7 mm +/- 0.75), and R (2.9 mm +/- 0.75) groups (F vs C or R p less than 0.05). This was associated with significant improvement in radial shortening in the jeopardized zone at 45 seconds into occlusion in the F group compared to the C and R groups (F = 21.1% +/- 5.1 vs C = 3.5% +/- 4.5 or R = 1.1% +/- 3.2; p less than 0.05). Results of electron microscopy showed reversible changes of ischemia within the mitochondria, and these were most marked in the C and R groups compared to the F group. Endothelial swelling was mild and was present only focally in the R and C groups. Thus perfluorochemicals may enhance the safety and efficacy of balloon angioplasty.

Adenine Nucleotides↗