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Biomedical subjects

A Laihinen

Publications and source records attributed to A Laihinen.

28 records · Page 2Linked to original sources
PubMed1990

Striatal kinetics of [11C]-(+)-nomifensine and 6-[18F]fluoro-L-dopa in Parkinson's disease measured with positron emission tomography.

The kinetics in brain of the dopamine reuptake blocking agent [11C]-(+)-nomifensine and the L-dopa analogue 6-[18F]fluoro-L-dopa were compared in 3 patients with idiopathic Parkinson's disease and age-matched healthy volunteers using positron emission tomography. Regional uptake was analyzed and quantified according to a 3-compartment model. Retention of both tracers in striatal regions of the parkinsonian patients were reduced compared with the healthy volunteers mainly in the putamen, while the caudate nucleus was only mildly affected. The reductions were considerably less than the decrease previously reported postmortem for striatal dopamine content in the basal ganglia of patients with Parkinson's disease. A fairly constant ratio between 6-[18F]fluoro-L-dopa utilization and [11C]-(+)-nomifensine binding in the caudate nucleus and the putamen were found in both groups unrelated to the size of the estimated parameters. This indicates that a limiting factor for the utilization of exogenous levodopa in Parkinson's disease may be a reduced transport capacity for the amino acid into the dopaminergic terminals.

Adult↗
PubMed1990

Brain substance P receptors in Parkinson's disease.

The distribution of SP receptors was studied both in the normal human brain and in the parkinsonian brain by means of tritiated SP. The highest levels of binding were found in the striatal areas and in the NbM. The distribution was similar to that found in laboratory animals in earlier studies. In PD the binding was significantly reduced in the NbM and parietal cortex as compared with controls. The level of SPLI was reduced in both parts of the SN, in the NbM, and in the GPi.

Aged↗
PubMed1987

Sleep movements and associated autonomic nervous activities in patients with Parkinson's disease.

Nine parkinsonian patients were studied during one night using the static charge sensitive bed (SCSB) method for the monitoring of respiration, ballistocardiogram (BCG) and body movements. The parkinsonian sleep was more restless than that of the controls. As the SCSB-defined levels of autonomic nervous activity were concerned, the amount of motor active wakefulness (MAW) was significantly (P less than 0.05) increased in parkinsonian patients, who also had less quiet sleep (P less than 0.05) than the controls. Parkinsonian tremor was present during 29.8 +/- 15.8% of the time in bed. Usually it was observed during wakefulness; it disappeared when the patient fell asleep. The frequency of turning-over events in bed was smaller in the parkinsonian patients than in the controls (P less than 0.05). When the heart rate changes associated with sleep movements were studied it was found that the parasympathetic deceleration component in the parkinsonian patients was absent. The motor dysfunction associated with Parkinson's disease is reflected in many ways in the sleep movement activity. Sleep disturbances in PD seem to be secondary in character; i.e. they can be due to impaired motor functions like turning around in the bed, or due to impaired arousal mechanisms during sleep.

Aged↗
PubMed1987

Psychosomatic aspects in dermatoses.

The purpose of this presentation is to offer a classification of psychocutaneous disease and to examinine factors which result in itching and scratching becoming chronic. Pruritus is a very common sensation in dermatoses. All forms of itching, whatever the cause, may be intensified by emotional stress. The patient sample of my own study consisted of seven diagnostic groups, giving a total of 99 patients. The dermatoses were: dermatitis herpetiformis, lichen ruber planus, chronic eczema, atopic eczema, neurodermatitis circumscripta, lichen corneus obtusus and pruritus psychogenes. The principal findings were as follows: 1. Many of the different mechanisms by which skin diseases became chronic had a psychological background. 2. Psychiatric disturbances were clearly more common than in the average population. Possibilities of psychiatric treatment were evaluated. The results confirm the hypothesis that in those skin diseases in which the disease mechanism is not yet sufficiently understood, psychosomatics is of considerable importance or offers an easier way to explain the mechanism.

Humans↗
PubMed1986

Function of dopamine receptors in Parkinson's disease: prolactin responses.

In 64 patients with Parkinson's disease (PD), the basal level of prolactin (PRL) was normal. Bromocriptine (BCT) caused a significant suppression of PRL in all parkinsonian patients and controls. When given after BCT treatment, thyrotropin-releasing hormone (TRH) induced a significantly lower PRL rise in recent-onset parkinsonian patients than in controls or advanced patients. In advanced parkinsonian patients with daily fluctuations in disability, the corresponding TRH-induced PRL response was significantly higher than in controls. In advanced parkinsonian patients without fluctuations, the PRL response to TRH was almost the same as in controls.

Aged↗
PubMed1983

Brain receptor changes in Parkinson's disease in relation to the disease process and treatment.

With regard to the behaviour of striatal D-2 receptors it was possible to divide parkinsonian patients into two subgroups, because either an increase or a decrease in the number of D-2 receptors was found. Dyskinesias, daily fluctuations in performance, and psychotic episodes together with neuroleptic medication, were associated with an increase in the number of striatal D-2 receptors. Clinically, the patients with a decreased number of striatal D-2 receptors were more disabled and had lost the beneficial response to levodopa. In agreement with post-mortem brain studies, increased responses of prolactin secretion to TRH in vivo also suggested a decreased D-2 receptor function in parkinsonian patients with recent onset and supersensitivity in patients with on-off phenomena. D-3 receptor binding sites had decreased in the parkinsonian striatum. In contrast to D-2 receptors, the D-3 sites seem to be less sensitive to treatment with neuroleptic drugs. Changes in the binding of 3H-enkephalins indicated that there is a supersensitivity of a population of enkephalin receptors (delta) in the striatum and limbic system. Treatment with levodopa did not have any significant effect on the binding of 3H-enkephalins. The binding of 3H-naloxone decreased in the parkinsonian caudate nucleus, suggesting that a population of opiate receptors (mu) is located on the dopamine nerve terminals in the striatum. Thus there are multiple neuronal disturbances in the parkinsonian brain, although those of nigrostriatal dopamine neurons seem to be greater and more closely related to the parkinsonian clinical features and to treatment responses.

Apomorphine↗
PubMed1979

Pontine gigantocellular field neuron activity time-locked with the PGO waves in the transitional phase of sleep in the cat.

The extracellularly recorded discharge of pontine gigantocellular tegmental field (FTG) neurons was studied in the cat during the transitional phase of sleep (TPS), which signifies in this study the shift from slow wave sleep (S) to paradoxical sleep (PS). The first appearance of pontogeniculo-occipital (PGO) waves, which were led off from the lateral geniculate nucleus, indicated the start, and the decrease of neck muscle tone the end of TPS. TPS was chosen because most PGO waves were then isolated and thus suitable for comparison with the discharge of neurons, which were localized to the antero-lateral part of the FTG. In order to analyze the possible role of these neurons in the control of PGO wave activity, the mean discharge rate of FTG neurons was studied in greater detail during 200 ms periods before and after the onset of each isolated PGO wave. Most FTG neurons discharged phasically and their activity was closely related to isolated PGO waves, so that the highest rate of unit discharge occurred within 40 ms period after the onset of the isolated PGO wave, being time-locked with its first deflection.

Animals↗
PubMed1978

The relationship between cortical recruiting responses and ponto-geniculo-occipital waves during paradoxical sleep in the cat.

In an earlier study it was found that during paradoxical sleep (PS) thalamo-cortical recruiting responses (RRs) and rapid eye movements usually did not appear simultaneously. As shown elsewhere, ponto-geniculo-occipital (PGO) wave activity and rapid eye movements are during PS closely related to each other in time. Similarly, in the present study it was observed that during paradoxical sleep in cats in which the center median nucleus of the thalamus was being stimulated at a rate of 7--9 Hz PGO waves in the geniculate nuclei did not in the rule occur in the presence of RRs recorded from the motor cortex. This effect was most pronounced with respect to series of PGO waves which usually occur at a rate of 4--7 Hz. On the basis of these experiments it was concluded that PGO waves and RRs are reciprocal events and mutually exclusive. Considering to the well-known fact that RRs represent synchronization, this negative correlation between RRs and PGO waves indicates that the desynchronizing tendency typical to paradoxical sleep is most pronounced during the occurrence of PGO waves.

Animals↗