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Biomedical subjects

S E Ewing

Publications and source records attributed to S E Ewing.

4 recordsLinked to original sources
PubMed1992

Recovery in hemiparkinsonian rats following intrastriatal implantation of activated leukocytes.

Behavioral improvement has been seen in hemiparkinsonian animals after surgical lesions of the denervated caudate nucleus. This study was designed to investigate the role of inflammatory cells in injury-induced recovery. A hemiparkinsonian syndrome was induced in rats by unilateral injections of 6-hydroxydopamine into the pars compacta of the substantia nigra. Phytohemagglutinin-stimulated rat peritoneal cells, predominantly T cells and macrophages, were stereotactically implanted in the lesioned caudate-putamen, and amphetamine-induced turning was used to assess recovery. Animals receiving implants of activated peritoneal cells showed a 47% decrease in amphetamine-induced turning 8 weeks after implantation, which was not seen in control or sham-operated animals. Immunocytochemistry revealed increased tyrosine hydroxylase reactive fibers in the leukocyte-implanted striatum. We conclude that implantation of activated leukocytes promotes functional recovery in hemiparkinsonian rats.

Animals↗
PubMed1989

A 6-hydroxydopamine-induced selective parkinsonian rat model.

Previous parkinsonian rat models have generally been characterized by unilateral destruction of both the nigrostriatal pathway and the mesolimbic pathway using the neurotoxin 6-hydroxydopamine (6-OHDA). We created a hemiparkinsonian model in which there is 6-OHDA-induced destruction of the dopaminergic nigrostriatal pathway but sparing of the dopaminergic mesolimbic pathway. This resulted in reproducible, quantifiable rotational behavior in response to either amphetamine or apomorphine and a near total depletion of dopamine in the striatum ipsilateral to the lesion with a dorsolateral distribution of supersensitive dopaminergic D2 receptors. This model parallels the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced hemiparkinsonian model in primates and more closely approximates the extent of neurodegeneration seen in human idiopathic Parkinson's disease than previous parkinsonian rat models. It may therefore prove a convenient model for studying the recently reported phenomenon of sprouting from host dopaminergic neurons following tissue implantation.

Amphetamine↗
PubMedDate not supplied

Tridimensional personality questionnaire and treatment response in major depressive disorder: a negative study.

BACKGROUND: Recent studies have found that the Tridimensional Personality Questionnaire can be used to help predict antidepressant treatment response in depressed outpatients. As this finding could be of great clinical importance, we attempted to replicate these findings. METHODS: Our study included 199 outpatients with major depressive disorder in an 8-week open trial with fluoxetine 20 mg/day. The Tridimensional Personality Questionnaire (TPQ) was administered to all patients before treatment. RESULTS: There was a significant correlation between pre-treatment scores on the TPQ subscale of harm avoidance and severity of depression at baseline as determined by Hamilton Depression Rating Scale-17 (HAM-D-17) scores. There was no correlation of harm avoidance scores and percent improvement of HAM-D-17 after treatment with fluoxetine. There was also no correlation of baseline HAM-D-17 scores or percent improvement with the subscales of reward dependence and novelty seeking. LIMITATIONS: Our study's limitations include a possible selection bias, lack of controls and fixed dosing of fluoxetine. CONCLUSIONS: In contrast to previous studies, we failed to find a relationship between temperament type as defined by the TPQ and antidepressant response. Our failure to replicate the findings of other studies may in large part be related to the use of different classes of antidepressants. Further studies using similar antidepressants may be helpful to clarify this discrepancy.

Adolescent↗