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Biomedical subjects

R G Robinson

Publications and source records attributed to R G Robinson.

At least 181 records · Page 10Linked to original sources
PubMed1988

Receptor characteristics and recovery of function following kainic acid lesions and fetal transplants of the striatum. II. Dopaminergic systems.

This experiment reports the development of striosomal-like patches in fetal striatal transplants grafted either into the intact, or kainic acid-lesioned, striatum of adult female rat brain. Although D2 receptor density approached control levels in the area of the patches, otherwise the transplanted striatum was relatively empty of dopamine receptors, and overall D2 development of the graft was strikingly reduced from controls. Transplants reversed lesion-induced hyperactivity under saline, but not amphetamine/apomorphine conditions, and led to an increased sensitivity of lesion and grafted animals following haloperidol injection. Transplants into the intact brain led to a lesion-like effect. M1 muscarinic cholinergic/D2 receptor density inversely correlated with behavior following amphetamine/apomorphine injections, while striatal cross-sectional area inversely correlated with activity after saline injection. These results suggest that abnormal maturation of the grafted striatum correlates with deficits in activity in grafted animals, and suggests that abnormal transplant development significantly impacts on transplant-induced behavioral changes.

Amphetamines↗
PubMed1988

Behavioral abnormalities induced by frontal cortical and nucleus accumbens lesions.

In previous studies, we have demonstrated that in male rats, unilateral right hemisphere lesions of either the frontolateral cortex or the nucleus accumbens (NAS) result in significant postoperative locomotor hyperactivity. In the present study we carried out two experiments to assess whether the production of hyperactivity in response to these two lesions is mediated through a common mechanism. In the first experiment, male Sprague-Dawley rats received either unilateral frontocortical suction and/or unilateral electrolytic lesions of the NAS. Only rats with lesions of the right hemisphere (suction and/or electrolytic) developed locomotor hyperactivity. Similar lesions in the left hemisphere did not result in behavioral changes. While both right cortical and NAS lesions alone produced hyperactivity, there was no additive effect of both lesions. In the second experiment, the effect of cortical lesions on NAS dopaminergic activity was assessed. Male Sprague-Dawley rats received either a right, left or sham frontocortical suction lesion, and were sacrificed 1, 2, and 4 weeks after surgery. Right hemisphere suction lesions produced a significant bilateral increase in NAS and caudate nucleus dopamine turnover (as measured by DOPAC/DA ratio) 4 weeks post-lesion, while similar left hemisphere lesions did not. These findings suggest that lesions in the dorsolateral frontal cortex and NAS may affect locomotor activity through a common mechanism mediated through the NAS.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Differential mood changes following basal ganglia vs thalamic lesions.

Patients with computed tomographic scan-verified unilateral lesions in the basal ganglia or thalamus were examined for the presence of poststroke mood disorders. Patients with left-sided basal ganglia lesions (mainly in the head of the caudate nucleus) showed a significantly higher frequency and severity of depression, as compared with patients with right-sided basal ganglia or thalamic (left- or right-sided) lesions. Results suggest that damage to biogenic amine pathways and/or frontocaudate projections may play an important role in the modulation of mood.

Aphasia↗
PubMed1988

Comparison of patients with and without poststroke major depression matched for size and location of lesion.

Patients who developed major depression within two years following stroke (n = 13) were compared with patients who did not become depressed in the same period (n = 13) but who did have a similar size and location of lesion as in the depressed group. Although the depressed patients were not significantly different from the nondepressed patients in background characteristics, history of depressive disorder, neurological impairment, or social functioning, the depressed group had greater cognitive impairment as measured by Mini-Mental State score. In addition, the depressed group had significantly larger lateral and third ventricular to brain ratios than nondepressed patients on computed tomographic scan analysis. The results suggest that poststroke depression itself may produce an intellectual impairment; subcortical atrophy, which likely preceded the stroke lesion, may produce a vulnerability for depression following stroke.

Aged↗
PubMed1988

Radioiodine therapy for differentiated thyroid carcinoma.

Radioiodine (iodine 131) is an effective form of adjuvant therapy that is frequently underutilized. A review of our recent experience was undertaken to assess the role of this treatment modality in the routine management of thyroid carcinoma. Over a 2-year period, 29 patients received adjuvant iodine 131 therapy. Ten of these patients (35 percent) were found to have local or distant metastasis by iodine-131 scan, and 7 (24 percent) had a metastatic lesion not suspected by operative findings or chest radiography. A complete response was obtained in 70 percent of the patients with metastatic disease. This study supports more frequent use of adjuvant radioiodine therapy in the management of differentiated thyroid carcinoma.

Adenocarcinoma↗
PubMed1988

Depressive disorders following posterior circulation as compared with middle cerebral artery infarcts.

Patients with cerebrovascular lesions in the posterior circulation territory (PC) were compared with patients having middle cerebral artery territory (MCA) strokes for the presence of mood disorders. Both groups showed a similar profile of clinical symptoms of depression during the acute evaluation in hospital. Patients with posterior circulation lesions involving the brainstem and/or cerebellum demonstrated a significantly lower frequency of depression than patients with MCA lesions or patients with posterior circulation lesions involving the left cerebral hemisphere. Moreover, depression following brainstem and/or cellebellar infarcts was of significantly shorter duration than depression following MCA lesions. These differences in the frequency and duration of depression following brainstem/cerebellar as compared with MCA lesions were not explained by differences in lesion volume, physical impairment, cognitive deficits or quality of social support. They suggest that PC and MCA induced depression may have different aetiologies.

Cerebral Arteries↗
PubMed1988

Mechanisms of mania after brain injury. 12 case reports and review of the literature.

Twelve patients who developed mania after a brain lesion are reported. Ages ranged from 20 to 83 years. Five patients had brain tumors (three frontal meningiomas, one temporal meningioma, and one temporal astrocytoma), four patients had stroke lesions (one frontal, one temporal, and two thalamocapsular), two patients had a traumatic frontal closed head injury, and one patient had a pituitary adenoma resection. Although seven patients had lesions restricted to the right hemisphere, four had bilateral or midline damage and one had a left hemisphere lesion. Damage to structures functionally connected to the obitofrontal cortex, mainly in the right hemisphere, seems to be associated with secondary mania. The possible roles of monoaminergic, genetic, and perinatal factors in the pathogenesis of secondary mania are discussed.

Adult↗
PubMed1988

Spinal compression fractures in osteoporotic women: patterns and relationship to hyperkyphosis.

A prospective study of thoracic and lumbar spinal fracture distribution and its relationship to thoracic kyphosis was performed in 87 women with osteoporosis. Anterior wedge fractures were most commonly seen in the midthoracic spine and about the thoracolumbar junction, whereas central compression fractures were most common from the first to the fourth lumbar levels. Solitary wedge fractures did not occur above the seventh thoracic vertebra, suggesting that a cause other than osteoporosis must be suspected in any patient with an isolated high thoracic fracture. Analysis of the spinal radiographs obtained in an additional 16 women without osteoporosis revealed that both forms of fracture were unusual in this small group with normal spinal mineralization. The number of anterior wedge fractures in the thoracic spine correlated (r = .546) with the degree of thoracic kyphosis. However, 19% of the women with no thoracic fractures still had thoracic hyperkyphosis. The authors conclude that the hyperkyphosis of osteoporotic women is related to anterior compression fractures but also has contributing nonskeletal factors.

Adult↗
PubMed1988

Comparison of spontaneously recovered versus nonrecovered patients with poststroke depression.

We followed 16 patients who developed depression immediately after a stroke for 6 months. By that time, six patients showed no depression (recovered group), while 10 patients were still depressed (nonrecovered group). There were no significant differences in demographic variables and social functioning between the groups, but the nonrecovered group showed less improvement in cognitive function and more physical impairments. Patients in the nonrecovered group had mainly cortical lesions, while those in the recovered group had mainly subcortical and posterior circulation strokes.

Adult↗
PubMed1988

Lateralized effect of cerebral infarction on spinal fluid monoamine metabolite concentrations in rats.

Using a rat model of stroke, we studied the effect of unilateral middle cerebral artery ligation on cerebrospinal fluid monoamine metabolites at different intervals over a 40-day postoperative period. Male Sprague-Dawley rats were divided into four groups: an unoperated control group (n = 9), a sham-operated group (n = 9), a right middle cerebral artery ligation group (n = 10), and a left middle cerebral artery ligation group (n = 10). One hundred microliters of cerebrospinal fluid were collected percutaneously from the cerebellomedullary cistern just before and 5, 20, and 40 days after the surgical procedure. Monoamine metabolites--3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxy-indoleacetic acid (5-HIAA), and homovanillic acid (HVA)--were measured using high-performance liquid chromatography. MHPG concentration in the right lesion group was significantly depleted from control levels 5, 20, and 40 days after surgery. No such depletion was observed in the left lesion rats. Concentration of 5-HIAA was relatively lower at Days 5 and 20 in the right lesion group than in the left lesion group. HVA concentration did not differ among the groups at any time. Our study has demonstrated a differential effect of unilateral ischemia on cerebrospinal fluid neurochemistry in rats dependent on the cerebral hemisphere involved.

Analysis of Variance↗
PubMed1988

Comparison of mania and depression after brain injury: causal factors.

Patients who developed secondary mania after brain injury (N = 17) had a significantly greater frequency of injury to right hemisphere areas connected with the limbic system than poststroke patients with major depression (N = 31), who had injury primarily in the left frontal cortex and basal ganglia. For patients without mood disturbance after brain injury (N = 28), the location of the lesion was not significant. Secondary mania patients also had a significantly greater frequency of family history of affective disorder than did the other two groups. These results suggest that an interaction between injury to certain areas of the right hemisphere and genetic factors or other neuropathological conditions produces secondary mania.

Aged↗
PubMed1988

PET imaging of cortical S2 serotonin receptors after stroke: lateralized changes and relationship to depression.

Patients with right-hemisphere strokes (N = 9) more than 1 year after injury had greater cortical binding of (3-N-[11C]methyl)spiperone than a similar group of patients with left-hemisphere strokes (N = 8) or normal control subjects (N = 17). The higher S2 serotonin receptor binding occurred in uninjured regions of the right parietal and temporal cortex. The ratio of binding in the ipsilateral to contralateral cortex showed a significant negative correlation with severity of depression scores in the left temporal cortex. These findings suggest that the biochemical response of the brain may be different depending on which hemisphere is injured and that some depressions may be a consequence of the failure to upregulate serotonin receptors after stroke.

Adult↗
PubMed1988

The sensitivity and specificity of the Center for Epidemiologic Studies Depression Scale in screening for post-stroke depression.

The present study examines the sensitivity and specificity of the Center for Epidemiologic Studies Depression Scale (CES-D) as a screening instrument for post-stroke depression. Eighty stroke patients were evaluated by a research nurse over a two-year period using the CES-D and also by a trained psychiatrist using a standardized interview for affective, cognitive, physical and social functioning. CES-D scores correlated significantly with DSM-III diagnoses of depression in-hospital and at three months, six months, and one year follow-up but not at two years follow-up, reflecting the natural course of these depressions, as well as the predictive validity of the CES-D. Furthermore, at a cut-off point of 16, the CES-D was found to have a specificity of 90 percent, a sensitivity of 86 percent and a positive predictive value of 80 percent and thus may be a potentially useful screening instrument for post-stroke depression.

Adult↗
PubMed1988

A two year longitudinal study of poststroke mood disorders: prognostic factors related to one and two year outcome.

In a prospective study of mood disorders in 103 stroke patients, we examined the predictive value of affective, cognitive, social and neurologic variables obtained in-hospital and at six months poststroke in terms of outcome as determined by the same measures at one and two years follow-up. The following factors were found to have prognostic significance: 1) Lesion Location: proximity of the lesion on CT scan to the frontal pole in patients with left anterior infarcts showed a strong positive relationship with severity of depression at one year but not at two years poststroke. 2) Affective Status: depression (in-hospital and at 6 months) strongly predicted depression at one year but not at two years poststroke. Additionally, in-hospital depression significantly correlated with physical impairment at two years, while depression at six months bore a moderate relationship to physical impairment at one year. 3) Physical Impairment: impairment in activities of daily living in-hospital bore a modest relationship to depression at one year while such impairment at six months correlated strongly with depression at both one and two years. These findings may reflect the natural course of major depression which remits between one and two years poststroke. Although stroke lesion location is the strongest predictor of subsequent depression, there appears to be a reciprocal relationship between physical impairment and depression (i.e., depression predicts impairment and impairment predicts depression). Since poststroke depressions are amenable to therapeutic intervention, these prognostic factors may have implications for the treatment and rehabilitation of stroke patients.

Adult↗