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Biomedical subjects

R Sandyk

Publications and source records attributed to R Sandyk.

At least 181 records · Page 10Linked to original sources
PubMed1990

Mexiletine for thalamic pain syndrome.

The thalamic pain syndrome, a rare sequelae of cerebrovascular event, is a severe and disabling form of central pain which treatment remains a major clinical problem. We present our results of a preliminary open label study using mexiletine, an orally active antiarrhythmic agent, in the management of thalamic pain in 9 patients. Using a dose of 10 mg/kg/day over a 4-week period, mexiletine produced improvement in pain in 8 of the 9 patients. Mexiletine was generally well tolerated with only two patients experiencing transient nausea and dizziness. Our findings suggest that mexiletine may be a safe and effective agent in the management of thalamic pain and possibly other paroxysmal pain syndromes of central origin.

Cerebral Hemorrhage↗
PubMed1990

The association of pineal calcification with drug-induced dystonic movements.

There is evidence that reduced melatonin secretion is associated with the pathophysiology of neuroleptic-induced movement disorders including tardive dyskinesia and Parkinsonism. It has been recently reported that pinealectomized rats developed increased incidence and severity of spontaneous chewing movements compared to normal controls. Increased chewing movements in rats has been suggested to reflect acute drug-induced dystonias in humans. To investigate the relationship between melatonin secretion and the pathophysiology of neuroleptic-induced dystonic movements, the presence and size of pineal calcification (PC) on CT scan was studied in relation to the severity of dystonic movements in 34 neuroleptic-treated chronic schizophrenic patients. The incidence of pathologically enlarged PC (greater than 1 cm in diameter) in the schizophrenic patients was 8-9 times greater than the incidence reported in the literature among nonpsychiatric patients. In addition, there were significant differences (p less than .0001) between the severity of dystonic movements in patients with no PC and those with pathologically enlarged PC, and between the severity of the dystonic movements in patients with PC of less than 1 cm and those with PC of greater than 1 cm diameter. These findings indicate an association between the pathophysiology of neuroleptic-induced dystonic movements and the presence of enlarged PCs and suggest that disturbances of melatonin secretion is associated with the emergence of neuroleptic-induced dystonic movements in schizophrenic patients. Further studies using direct measurements of plasma melatonin levels are required more precisely to confirm the association between pineal melatonin secretion and the pathophysiology of drug-induced dystonic movement disorders.

Adult↗
PubMed1990

Pineal calcification and subtypes of tardive dyskinesia.

There is evidence that reduced melatonin secretion is associated with the pathophysiology of tardive dyskinesia (TD). To investigate the relationship between melatonin secretion and TD, I evaluated scores of subtypes of TD with CT scan measurements of pineal calcification (PC) size in 77 chronic institutionalized schizophrenic and bipolar patients. There was a significantly greater incidence of pathologically enlarged calcified pineal glands (greater than 1 cm in diameter) in the patients (18.1%) compared to the reported incidence in the literature in nonpsychiatric subjects (1%). In addition, there was a significant association between scores of limb-axial (but not orofacial) dyskinesias and the presence of pathologically enlarged PC (p less than 0.05). These findings support the notion that the pathophysiology of orofacial dyskinesias may be distinct from limb-axial dyskinesias. In addition, since it is possible that a pathologically enlarged calcified pineal gland is associated with reduced melatonin secretion, these findings add further support to implicate decreased melatonin secretion in the pathophysiology of TD. Further studies using direct measurements of plasma melatonin levels are required to define more precisely the relationship between TD and melatonin secretion.

Adult↗
PubMed1990

The relationship between ECT nonresponsiveness and calcification of the pineal gland in bipolar patients.

It has been suggested recently that the therapeutic effects of electroconvulsive therapy (ECT) may be mediated in part through stimulation of pineal melatonin secretion. If melatonin does mediate the antidepressant effects of ECT and depression itself is associated in some patients with reduced melatonin secretion, patients with reduced melatonin secretion could respond less readily to ECT. There is evidence to suggest an inverse relationship between melatonin secretion and the degree of pineal calcification. Specifically, heavy pineal calcifications in animals have been reported to be associated with reduced plasma melatonin levels. In this study, an investigation was conducted to establish more precisely the relationship between the clinical response to ECT in 17 bipolar patients and the degrees of pineal calcification present on CT scan. There was a significant association between ECT nonresponsiveness and the presence of pathologically enlarged pineal calcification (i.e., greater than 1 cm in diameter) (p.01). In addition, there was a significant difference in ECT responsiveness in patients without pineal calcification compared to those with pathologically enlarged pineal calcification (F = 6.10; p = .01, one-way ANOVA). These findings indicate an association between enlarged pineal calcification and ECT nonresponsiveness and suggest that reduced melatonin secretion may be associated with ECT nonresponsiveness. An enlarged pineal calcification could be a useful radiological marker of ECT nonresponsiveness and administration of melatonin precursors (i.e., L-tryptophan; 5-HTP) and its cofactors (i.e., pyridoxine, folate) as well as melatonin-release enhancing agents (i.e., 5-methoxypsoralen) prior to ECT might augment its antidepressant effects in bipolar patients.

Adult↗
PubMed1990

The relationship of pineal calcification to subtypes of tardive dyskinesia in bipolar patients.

Recent studies have suggested that bipolar patients may be at high risk for developing tardive dyskinesia (TD) if exposed to chronic neuroleptic therapy. It has been suggested that reduced melatonin secretion may favor the development of TD in bipolar and schizoaffective patients. Since pinealectomized rats have been reported to develop increased incidence and severity of abnormal chewing movements, and as depression is associated with reduced melatonin secretion, the increased risk of TD in bipolar patients may be associated with diminished melatonin secretion. Evidence suggestive of an inverse correlation between pineal calcification and reduced melatonin secretion, led me to study the relationship between pineal calcification on CT scan and the severity of axial (truncal) and limb and orofacial dyskinesias in bipolar patients with TD. The incidence of pathologically enlarged pineal calcifications (i.e., greater than 1 cm in diameter) in the bipolar patients was 25 times greater than the reported incidence in the literature among nonpsychiatric patients. In addition, there was a significant difference in scores of axial dyskinesias between patients with pineal calcification of less than 1 cm in diameter compared to those with pineal calcification of greater than 1 cm in diameter (F = 3.24; p = .04, one-way ANOVA). There was no significant association between scores of limb and orofacial dyskinesias and pineal calcification. These findings suggest a meaningful association between the presence of enlarged pineal calcification, and axial dyskinesias in bipolar patients. Further studies using direct plasma melatonin measurements are required to more precisely define the association between TD and melatonin secretion in bipolar patients.

Adult↗
PubMed1990

The relationship between ECT responsiveness and subtypes of tardive dyskinesia in bipolar patients.

Despite intensive research, the mechanisms of action of electroconvulsive therapy (ECT) remain elusive. In addition, there are no known biological factors predicting ECT responsiveness in bipolar patients. A study was conducted to investigate the relationship between ECT responsiveness and tardive dyskinesia (TD), a common side effect of neuroleptic therapy, and its subtypes (i.e., orofacial and limb-axial dyskinesias) in a group of 18 bipolar patients. There was a significant difference in orofacial dyskinesia scores between ECT responders and non-responders (p less than 0.005), while there was no significant association in scores of limb-axial dyskinesia between ECT responders and non-responders. These findings suggest an association between ECT responsiveness and the presence of orofacial dyskinesias in bipolar patients with TD and add further support to the notion that TD is a heterogeneous disorder comprising at least two subtypes with distinct underlying pathophysiological mechanisms.

Adult↗
PubMed1990

Pineal melatonin functions: possible relevance to Parkinson's disease.

Barbeau hypothesized that Parkinson's disease is associated with hypothalamic deficiency of the specialized neuroendocrine cell system (A.P.U.D.) and that the degeneration of brainstem monoaminergic neurons is secondary to progressive functional loss of this cell system in the disease. The pineal gland meets criteria of the A.P.U.D. cell system and it is possible that dysfunction of the pineal gland may be associated with the pathophysiology and clinical manifestations of Parkinson's disease. Since the role of pineal melatonin in humans remains enigamatic, it is currently unclear which of the symptoms of Parkinson's disease may be associated with deregulation of the secretory activity of pineal melatonin. This review summarizes evidence linking possible alterations of pineal melatonin functions with the clinical manifestations of Parkinson's disease.

Animals↗
PubMed1990

Mechanisms of action of ECT in Parkinson's disease: possible role of pineal melatonin.

Recent clinical studies have suggested that electroconvulsive therapy (ECT) may be efficacious in the therapy of Parkinson's disease (PD). However, the mechanisms of action of ECT in PD are largely unknown. PD may be associated with reduction in the secretory activity of pineal melatonin, and the therapeutic efficacy of ECT in PD may be associated with an effect on the secretory activity of pineal melatonin. Further studies involving analysis of plasma melatonin levels and circadian release prior to and following ECT are needed more precisely to determine the role of pineal melatonin in PD and in the therapeutic efficacy of ETC in PD.

Electroconvulsive Therapy↗
PubMed1990

Serial epilepsy caused by levodopa/carbidopa administration in two patients on hemodialysis.

Two patients with similar clinical features are presented: both patients had chronic renal failure, on hemodialysis for many years but recently begun on a high-flux dialyzer; both had been receiving a carbidopa/levodopa preparation; and both had the onset of hallucinosis and recurrent seizures, which were refractory to anticonvulsants. The first patient died without a diagnosis; the second patient had a dramatic recovery following the administration of vitamin B6. Neither patient was considered to have a renal state sufficiently severe enough to explain their presentation.

Aged↗
PubMed1990

Mood-dependent fluctuations in the severity of tardive dyskinesia and psoriasis vulgaris in a patient with schizoaffective disorder: possible role of melatonin.

There is evidence that patients with affective disorders are at high risk for developing Tardive dyskinesia (TD). In addition, in patients with bipolar illness, depressive episodes have been associated with exacerbation of the TD, while manic episodes were accompanied by attenuation of TD. Since depression is associated with diminished melatonin secretion, the high incidence of TD in patients with history of depression may be linked to diminished secretory activity of the pineal melatonin. We report a 28-year old female patient with schizoaffective disorder associated with psoriasis vulgaris in whom periodic exacerbation of depressive moods and suicidal thoughts were accompanied by worsening of the TD as well as the psoriatic lesions. Spontaneous improvements of mood were associated with disappearance of the involuntary movements and regression of the psoriatic lesions. Since melatonin secretion is diminished in patients with depression and in patients with psoriasis vulgaris, this report may add further support to the hypothesis that the development of TD may be associated with diminished secretory activity of pineal melatonin. The mechanisms by which diminished melatonin secretion may facilitate the emergence of TD are discussed. In addition, the possibility that light therapy, as has been successfully used in the management of seasonal affective disorders, may be useful in the management and perhaps prophylaxis of TD is discussed.

Adult↗
PubMed1990

Seborrhea and persistent tardive dyskinesia.

The following communication concerns two schizophrenic patients with Tardive dyskinesia (TD) in whom fluctuations in the severity of the dyskinesias were accompanied by changes in the severity of the seborrheic skin lesions. Since seborrheic dermatitis may be associated with increased plasma melanocyte-stimulating hormone (MSH) level, these observations suggest an association between the severity of TD and increased pituitary MSH release. In addition, TD may be associated with hypothalamic-pituitary dysfunction of MSH autoregulation.

Adult↗
PubMed1990

Increased incidence of neuroleptic-induced perioral movements in the rat by hyperglycemia.

It has been suggested that Tardive dyskinesia (TD) is associated with abnormal glucose metabolism. To investigate further the issue the effects of alloxan-induced hyperglycemia on the incidence and severity of haloperidol-induced perioral movements were studied in the rat. Hyperglycemic rats showed significantly higher incidence and severity of rating of abnormal perioral movements than did control rats. Severity ratings of perioral movements were significantly correlated with blood glucose levels in the hyperglycemic rats. These findings suggest that hyperglycemia may increase the severity of neuroleptic-induced perioral movements, and support the possibility that glucose intolerance may increase the risk of TD.

Alloxan↗
PubMed1990

The relationship of negative schizophrenia to parkinsonism.

The positive-negative distinction of schizophrenia has emerged as a valid means of clarifying its heterogeneity. Despite evidence that the two symptom classes may reflect different dimensions of the disease, there is presently no integrated model for understanding of the pathophysiology of these symptoms and their co-occurrence in schizophrenia. We propose that negative phenomena of schizophrenia may be a variant of Parkinsonism. This view is supported by the overlap with Parkinsonism in terms of clinical features, neurochemistry, pharmacology, as well as neuroradiological and neuropathological aspects. As such, negative symptoms may be a manifestation of disease of the basal ganglia and constitute the core pathology in schizophrenia. Positive symptoms, conversely, may reflect an "accessory" process related to a compensatory increase in striatal and limbic dopamine activity following an injury to the dopaminergic system. In the present communication we present a series of studies that support the association of negative schizophrenia and Parkinsonism. Based on this evidence, we suggest that schizophrenic patients with prominent negative symptoms might be managed like patients with Parkinson's disease, namely, with dopaminergic drugs and MAO-B inhibitors. Finally, the association of negative schizophrenia with Parkinsonism raises the possibility that adrenal medullary tissue transplantation, which may benefit a selected group of Parkinsonian patients, may be a future promising therapy for refractory negative schizophrenia.

Adult↗
PubMed1990

MIF-induced augmentation of melatonin functions: possible relevance to mechanisms of action of MIF-1 in movement disorders.

MIF-1, a synthetic tripeptide with MSH-release inhibitory properties, has been reported to improve symptoms of Parkinson's disease, attenuate levodopa-related dyskinesias and diminish the dyskinetic movements of Tardive dyskinesia. More recently, MIF-1 has been reported partially to protect against the nigro-striatal dopamine depleting effects of MPTP in mice, raising the possibility that it may exert protective effects against the development of Parkinson's disease. There is evidence to suggest that MIF-1 increases nigro-striatal dopaminergic activity, but its ability to improve symptoms in patients with Parkinson's disease, levodopa-related dyskinesias and Tardive dyskinesia cannot be explained solely on the basis of the drug's effect on striatal dopaminergic neurons. MIF-1 has been reported to potentiate the melanocyte-lightening effect of melatonin in rats and its effects in patients with Parkinson's disease and Tardive dyskinesia are associated with marked mood elevation. It is, therefore, possible that the effects of MIF-1 in movement disorders are associated with increased melatonin secretion. Thus, hypothalamic MIF may modulate nigro-striatal dopaminergic functions in part via pineal melatonin. Such an interaction represents a novel mechanism by which hypothalamic peptides act to modulate the expression of movement disorders.

Affect↗