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J O Rinne

Publications and source records attributed to J O Rinne.

At least 19 recordsLinked to original sources
PubMed1992

Decrease in mesencephalic dopamine autoreceptors in experimental herpes simplex encephalitis.

Brain dopamine receptors were determined in experimental herpes encephalitis using an animal model, where herpes simplex virus type 1 was inoculated onto the cornea of rabbits. The animals exhibit an asymmetric posture and circling to the side of inoculation, which appears to be connected to the altered dopamine transmission in the mesostriatal system. In this study striatal and mesencephalic D-1 and D-2 dopamine receptors were measured by radioligand techniques using 3H-SCH 23390 and 3H-spiroperidol as ligands. In the striatal D-1 and D-2 receptors there were no significant differences between HSV-inoculated and control rabbits. In the substantia nigra-ventral tegmental area there was a significant decrease in the D-2 receptors (Bmax) on the side contralateral to the primary virus inoculation and the direction of the rotational behaviour, without any changes in the D-1 receptors. Thus experimental herpes simplex virus infection seems to affect the mesencephalic dopamine autoreceptors, leading to unilateral activation of the mesostriatal dopamine system and rotational behaviour.

Animals↗
PubMed1992

[18F]-6-fluorodopa PET scanning in Parkinson's disease after selective COMT inhibition with nitecapone (OR-462).

PET studies were performed to investigate the effects of a new cathechol-O-methyltransferase (COMT) inhibitor, nitecapone (OR-462 [3-(3,4-dihydroxy-5-nitrobenzylidene)- 2,4-pentadione]), on the accumulation of dopamine in the striatum and whether it is able to improve [18F]6-fluorodopa imaging of the brain. Altogether, three patients with Parkinson's disease (PD) and three normal volunteers were examined, first without nitecapone and then with an oral dose of 100 mg of nitecapone 1 hour before the IV injection of 3 mCi of [18F]6-fluorodopa. High-pressure liquid chromatography analysis of arterial plasma samples showed a significant reduction in the metabolic conversion rate from [18F]6-fluorodopa to [18F]3-O-methylfluorodopa after the administration of nitecapone. PET studies showed that nitecapone significantly (p less than 0.05) increased the [18F]6-fluorodopa accumulation in the striatum both in PD patients and normal controls; the magnitude of this increase was 20.0 +/- 5.5% (mean +/- SEM). The ratio of radioactivity in the striatum and arterial plasma was increased 39.0 +/- 5.0% (mean +/- SEM) after the administration of nitecapone. Consequently, the quality of PET images after OR-462 was better, which has implications for future [18F]6-fluorodopa studies. In addition, COMT inhibition may have clinical advantages by improving levodopa treatment in PD.

Adult↗
PubMed1991

A post-mortem study on striatal dopamine receptors in Parkinson's disease.

Striatal dopamine D1 and D2 receptors were investigated in 49 patients with Parkinson's disease (PD) and 33 age-matched controls with [3H]SCH 23390 and [3H]spiroperidol as ligands respectively. A full Scatchard analysis giving Bmax and Kd values was performed. In the caudate nucleus, a small but significant decrease in the number of D1 and D2 receptors was seen, whereas in the putamen the number of dopamine receptors was unchanged. Treatment with neuroleptics was found to increase the number of D2 receptors both in the caudate nucleus and putamen. The number of neither D1 nor D2 receptors correlated neither with the duration of disease or levodopa treatment of the patients nor with the post-mortem delay or storage time of the samples. Furthermore, no association was found between either D1 or D2 receptor number and clinical variables of the patients. The activity of choline acetyltransferase (ChAT) was found to be unchanged in the striatum, whereas a marked decline was seen in the hippocampus and cortical areas, indicating that intrinsic striatal cholinergic neurons are not affected in PD. The present results suggest that there is a modest decline in the number of striatal dopamine D2 receptors in advanced patients with PD at the end stage of the disease.

Aged↗
PubMed1991

A postmortem study of brain nicotinic receptors in Parkinson's and Alzheimer's disease.

Brain nicotinic receptors were studied in the frontal cortex, temporal cortex, hippocampus and caudate nucleus in patients with Parkinson's disease (PD), Alzheimer's disease (AD) and control. The Bmax and Kd values of (-)-[3H]nicotine binding were determined with a Scatchard analysis. The number of nicotinic receptors declined both in PD and in AD patients in all brain areas examined. The Kd values were unchanged. There was a negative correlation between the degree of dementia in PD patients and the number of nicotinic receptors in the frontal cortex. A similar correlation was seen between the muscarinic/nicotinic receptor ratio in the frontal cortex and the degree of dementia in PD patients. The present findings indicate that nicotinic receptors are affected not only in AD, but also in PD and that dysfunction of the cholinergic system in the frontal cortex is involved in the dementia process in PD.

Aged↗
PubMed1991

Nigral degeneration in Parkinson's disease in relation to clinical features.

Neuronal loss in the substantia nigra (SN) in Parkinson's disease (PD) shows a topographical organisation where the lateral part of the SN is more affected. This is--due to projection of the lateral SN mainly to the putamen--reflected in more complete loss of dopamine content in the putamen than in the caudate nucleus. Of the parkinsonian symptoms rigidity and hypokinesia are associated with neuronal loss in the lateral substantia nigra and the resulting dopamine loss in the putamen. Neuronal mechanisms other than degeneration of the nigrostriatal system seem to be involved in the pathophysiology of tremor. Cognitive impairment and dementia in PD is related to dysfunction of the cortical cholinergic system, especially in the frontal cortex. The brain dopaminergic system, however, contributes as a subcortical component to cognitive impairment in PD. Clinical studies have shown that selegiline may slow down the progression of PD. We studied postmortem samples of patients treated with selegiline and levodopa and those with levodopa alone. The number of medial nigral neurons was significantly higher in the selegiline group. Treatment with selegiline might retard the death of nigral neurons, but further studies are needed to confirm the preliminary findings.

Corpus Striatum↗
PubMed1991

Selegiline (deprenyl) treatment and death of nigral neurons in Parkinson's disease.

We studied the effect of selegiline (deprenyl) treatment on the number of Lewy bodies and neuron counts in the substantia nigra in patients with Parkinson's disease (PD). The number of medial nigral neurons was greater and the number of Lewy bodies fewer in those PD patients who had been treated with selegiline in combination with levodopa as compared with patients who had received levodopa alone. This suggests that selegiline treatment may retard the death of nigral neurons, but alternative explanations, such as the reduction of levodopa dosage in selegiline-treated patients, are possible.

Aged↗
PubMed1990

Age-dependent decline in human brain dopamine D1 and D2 receptors.

Dopamine D1 and D2 receptor binding was investigated in the caudate nucleus and putamen in 65 individuals ranging from 6 to 93 years of age. [3H]SCH 23390 and [3H]spiroperidol were used as ligands for D1 and D2 receptors, respectively. A full Scatchard analysis with several ligand concentrations was performed yielding Bmax and Kd values. The number of D1 and D2 receptors declined with age both in the caudate nucleus and putamen without any change in the mean dissociation constant. The ratio of D1:D2 receptors remained unchanged. The results show that the dopaminergic system degenerates in the aging striatum and may contribute to the frequent occurrence of extrapyramidal symptoms in the elderly.

Adolescent↗
PubMed1990

PET demonstrates different behaviour of striatal dopamine D-1 and D-2 receptors in early Parkinson's disease.

Striatal dopamine D-1 receptor binding was investigated in vivo with positron emission tomography (PET) in five patients with early Parkinson's disease using [11C]-SCH 23390. All patients had predominantly unilateral symptoms and showed a significant reduction in the accumulation of [18F]-6-F-DOPA in the striatum contralateral to the symptoms. None of the patients had received any antiparkinsonian medication. The striatal and cerebellar radioactivity was measured and corresponding striatum/cerebellum ratios were counted. The mean striatum/cerebellum ratio of [11C]-SCH 23390 binding was symmetric between the hemispheres. By contrast, the striatum/cerebellum ratio of [11C]raclopride binding, labelling dopamine D-2 receptors, was increased significantly in the hemisphere contralateral to the symptoms as compared with the opposite hemisphere. Thus, the present results show that the behaviour of striatal D-1 and D-2 receptors is different in early Parkinson's disease.

Adult↗
PubMed1990

Positron emission tomography demonstrates dopamine D2 receptor supersensitivity in the striatum of patients with early Parkinson's disease.

Striatal dopamine D2 receptor binding was studied in vivo with positron emission tomography in seven patients with early Parkinson's disease using [11C]-raclopride. The patients had unilateral symptoms and none of them had received levodopa treatment. The accumulation of [11C]-raclopride in the striatum was rapid and reached a steady state at approximately 40 min after injection. The binding of [11C]-raclopride was measured in the striatum and cerebellum: The total striatal radioactivity in both hemispheres was counted and the respective striatum/cerebellum ratios were calculated. The striatum/cerebellum ratio of [11C]-raclopride binding was significantly (p less than 0.01) increased in the hemisphere contralateral to the parkinsonian symptoms as compared with the opposite hemisphere. Thus, this study demonstrates that there is denervation supersensitivity in dopamine D2 receptor binding in early Parkinson's disease.

Adult↗
PubMed1989

Brain muscarinic receptor subtypes are differently affected in Alzheimer's disease and Parkinson's disease.

The muscarinic receptor subtypes determined by displacing [3H]quinuclidinyl benzylate by carbachol showed distinct profiles in Alzheimer's disease (AD) and in Parkinson's disease (PD). A decrease in the M2-receptor count was seen in the hippocampus in AD as compared to controls, while PD patients had unaltered binding. By contrast, PD patients had increased M2-binding in the frontal and temporal cortex, whereas unchanged binding was seen in AD. In PD the total number of cortical muscarinic receptors was negatively associated with the activity of ChAT, but had a positive correlation with the degree of dementia of the patients.

Aged↗
PubMed1989

Dementia in Parkinson's disease is related to neuronal loss in the medial substantia nigra.

Regional neuronal loss in the substantia nigra was studied in relation to extrapyramidal symptoms and dementia in 12 patients with idiopathic Parkinson's disease (PD) and in 18 control subjects. Four areas of the right substantia nigra were investigated at the level of the superior colliculus and caudal red nucleus. In Parkinson's disease, the percentages of neurons, from the medial to the lateral part of the substantia nigra, were reduced to 49%, 31%, 41%, and 25% of the control values. The number of neurons in the lateral part showed a negative correlation with the severity of rigidity and hypokinesia, whereas tremor was less noticeable in patients with few neurons. The degree of dementia of the patients had a significant correlation only with neuronal loss in the medial part of the substantia nigra, suggesting, in view of the topographical organization of the neurons in the substantia nigra, that intact projections to the caudate nucleus and limbic and cortical areas are a prerequisite for normal cognitive functioning and that their dysfunction leads to clinical dementia.

Aged↗
PubMed1989

Different forms of brain acetylcholinesterase and muscarinic binding in Parkinson's disease.

Choline acetyltransferase (ChAT) activity, the sedimentation and solubility forms of acetylcholinesterase (AChE) as well as total (3H-quinuclidinyl benzilate, QNB) and M1 (3H-pirenzepine, PZ) muscarinic binding were investigated in the temporal cortex (TC) and nucleus caudatus (NC) of both non-demented and demented parkinsonian patients and controls. ChAT activity and low-salt-soluble and detergent-soluble AChE were lower in the TC of demented patients with Parkinson's disease than in controls. ChAT activity and the solubility forms of AChE in the NC did not differ between controls and parkinsonian patients. In the TC, the activity of the intermediate form of AChE was lower in parkinsonian patients, but the activity of the light form of AChE did not differ between controls and parkinsonian patients. In the TC of patients with Parkinson's disease the Bmax of 3H-QNB binding was slightly higher than in controls, but the Bmax of 3H-PZ binding did not differ between controls and parkinsonian patients. In the NC the Bmax of 3H-QNB binding was unchanged compared to that of the controls. The concomitant decrease of ChAT with soluble as well as membrane-bound tetrameric AChE suggests a close relationship between ChAT and tetrameric form of AChE. M1 receptors (3H-PZ binding sites) are not affected in the TC, but are decreased in the NC of demented parkinsonian patients. This decrease may be secondary to the loss of dopaminergic neurons projecting from the substantia nigra to the striatum.

Acetylcholinesterase↗
PubMed1989

Treatment of early Parkinson's disease with controlled-release levodopa preparations.

Therapeutic responses to Sinemet CR were studied in 37 patients with early Parkinson's disease previously treated with standard (Madopar) or controlled-release (Madopar HBS) levodopa/benserazide combinations. Patients were followed up for a 3-month period. The optimal therapeutic response of parkinsonian disability to Sinemet CR was equal to that obtained with Madopar or Madopar HBS. The optimal therapeutic dosage of Sinemet CR was equal to that of Madopar HBS but 12% higher than that of standard Madopar. However, with Sinemet CR treatment, the number of daily doses needed was significantly fewer than with both previous treatments. End-of-dose failure, which had developed in 4 patients, and peak-dose dyskinesias present in 6 patients during treatment with standard Madopar, improved significantly with Sinemet CR. Thus, Sinemet CR seems to be beneficial and useful in the treatment of early Parkinson's disease.

Aged↗
PubMed1989

Neuronal loss in the substantia nigra in patients with Alzheimer's disease and Parkinson's disease in relation to extrapyramidal symptoms and dementia.

Regional neuronal loss in the substantia nigra (SN) was studied in relation to extrapyramidal symptoms and dementia in 27 patients with Alzheimer's disease (AD), 12 patients with idiopathic Parkinson's disease (PD) and 18 controls. Four areas of the right SN were investigated at the level of the caudal red nucleus. In AD the number of neurons were reduced to 97%, 79%, 83% and 78% of the control values from the medial to lateral SN respectively. The number of lateral neurons showed a negative correlation with the severity of rigidity and hypokinesia. The degree of dementia did not have a significant correlation with nigral neuronal counts. In PD, the number of neurons was markedly reduced in all parts of the SN, most pronouncedly in the lateral part. The number of lateral neurons showed a negative correlation with the severity of rigidity and hypokinesia, whereas tremor had a positive correlation. The degree of dementia of the patients had a negative correlation with the number of medial neurons, suggesting that degeneration of the nigrostriatal neurons may contribute as a subcortical component to dementia in PD patients.

Aged↗
PubMed1988

Free amino acids in the brain of patients with Parkinson's disease.

To study free brain amino acids and their relation to dementia, the levels of glutamate, glutamate, asparagine, aspartate, glycine, taurine, homocarnosine and gamma-aminobutyric acid were determined in the temporal cortex and caudate nucleus in demented and non-demented patients with Parkinson's disease. In the temporal cortex, the levels of aspartate and asparagine were significantly increased in non-demented parkinsonian patients as compared both to demented patients and to controls. In the caudate nucleus no significant changes in amino acid levels were seen. Thus, the cortical and striatal glutamate/aspartate systems seem to be preserved in dementia in Parkinson's disease.

Aged↗
PubMed1988

A comparison of brain choline acetyltransferase activity in Alzheimer's disease, multi-infarct dementia, and combined dementia.

Brain choline acetyltransferase (ChAT) activity was determined in 43 patients with Alzheimer's disease (AD), 14 with multi-infarct dementia (MID), and 15 with combined dementia (CD) and in 53 age-matched controls. The activity of ChAT declined in the hippocampus, temporal and frontal cortex in patients with AD and CD compared to the controls. In the AD group the reduced activity of ChAT in all brain areas was associated with a greater number of cortical neurofibrillary tangles. The degree of dementia had a negative correlation with the activity of ChAT in the frontal cortex in both AD and CD patients. The activity of ChAT in the temporal cortex of CD patients was negatively associated with the cortical tangle counts. In contrast, the activity of ChAT and MID patients was not essentially different from that of the controls. Neither did the various clinical and neuropathological variables show any significant correlation with ChAT activity in MID patients. Thus, in this study the reduction in the activity of ChAT seems to be associated with Alzheimer-type pathology but not with dementia due to vascular changes.

Aged↗