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J M Rabey

Publications and source records attributed to J M Rabey.

At least 37 records · Page 2Linked to original sources
PubMed1998

Dopamine uptake by platelet storage granules in first-degree relatives of Tourette's syndrome patients.

BACKGROUND: Considering that platelets have been established to be good peripheral markers for the study of catecholaminergic neurons, we have applied an assay to measure the uptake of (3H)-dopamine (DA) into platelet storage granules (PSG). Recently, we reported that Tourette's syndrome (TS) patients (pts) show decreased DA uptake into PSG. METHODS: In the present study, 28 first-degree relatives (3 with chronic motor tics, 3 with transient tics, 6 with obsessive-compulsive behavior, and 16 without symptomatology) belonging to the families of 13 patients, and 14 unrelated healthy controls were studied. RESULTS: Double reciprocal plots were constructed for each subject, and the apparent maximum velocity (Vmax) and Michaelis constant (K(m)) were determined by linear regression analysis (Lineaweaver-Burke plots). The uptake of DA (0.5-5 mumol/L) (mean +/- SEM) by PSG from relatives with symptomatology was similar to the TS patients (symptomatic relatives Vmax 181 +/- 22.2 fmol/mg protein, K(m) (mumol/L) 6.42 +/- 0.29; TS pts Vmax 108 +/- 6.9, K(m) 7.79 +/- 0.64). Relatives without symptomatology on the contrary showed DA affinity characteristics similar to the controls (t test, paired t test, multivariate analysis of variance, and log transformation). CONCLUSIONS: The data presented suggest that TS is hereditary, but they do not distinguish between an autosomal dominant inheritance and a mixed or polygenic model.

Blood Platelets↗
PubMed1998

Neurosurgical intervention for cervical disk disease in dystonic cerebral palsy.

We report five young patients with athetoid-spastic cerebral palsy who had deteriorated neurologically. Magnetic resonance imaging (MRI) was used to investigate suspected compressive cervical spine lesion. Cervical spondylosis with disk protrusions was found in all patients. Four patients underwent surgery by an anterior approach with insertion of a bone graft resulting in substantial clinical improvement. The other patient, diagnosed 8 years after onset of symptoms, was treated conservatively. The availability of MRI makes early recognition of cervical cord compression possible, allowing effective surgical intervention in this special group of patients.

Adult↗
PubMed1998

Indication to surgical management of cerebellar hemorrhage.

Few reports have compared patients operated for cerebellar infarcts with those operated for cerebellar hemorrhage. Considering our previous paper about patients with massive cerebellar infarcts, we report on our surgical experience with five patients with cerebellar hemorrhage. The indication for operation was decreased consciousness with signs of brainstem compression. In all patients hydrocephalus was absent or mild, as opposed to patients with cerebellar infarcts. Suboccipital craniotomy with hematoma evacuation was therefore the surgical procedure of choice. The outcome was worse than in patients with cerebellar infarcts. We conclude that depressed mental state in cerebellar hemorrhage is mainly due to pressure of the cerebellum on the activating reticular system of the brainstem. The surgical approach to patients with bleeding in the cerebellum differ somewhat from that of patients with cerebellar infarcts in timing and kind of first choice procedure.

Aged↗
PubMed1998

Quantified EEG in patients with vertigo of central or peripheral origin.

Computerized EEG frequency analysis was performed in 18 patients with peripheral vestibular dysfunction (PVD), 17 patients with central vestibular dysfunction (CVD) and 22 aged matched controls. Increase in the relative theta activity in the centrotemporal region was found in patients with PVD. The decrease of centroparietal beta activity in both groups of patients, as compared to controls, did not reach statistical significance. We conclude that quantified EEG may be a sensitive method to show changes of cortical electrical activity in patients with vertigo, reflecting the imbalance in afferent vestibular input to the cortex.

Adult↗
PubMed1997

Evaluation of the Short Parkinson's Evaluation Scale: a new friendly scale for the evaluation of Parkinson's disease in clinical drug trials.

The extensive use of the Unified Parkinson's Disease Rating Scale (UPDRS) has revealed low interrater reliability in some items and redundancy in others. In view of these shortcomings, we have structured a new scale that includes a zero-to three-point scale for each item in the evaluation of PD. The mental axis includes memory, thought disorders, and depression. Activities of daily living (ADL) includes eight items: speech, eating, feeding, dressing, hygiene, handwriting, walking, and turning in bed. The motor examination includes eight items: speech, tremor, rest and posture, rigidity, finger tapping, arising from chair, gait, and postural stability. Complications of therapy were also included: dyskinesias, dystonia, motor fluctuations, and freezing episodes, collected by history. In addition, a global scoring for motor fluctuations that should complement the Hoehn and Yahr Scale was incorporated. In this report, we present a statistical analysis of the ADL, motor evaluation, and complications of therapy sections. Concerning the interrater reliability mean, Kendall's W values were >0.9 for most of the items in the Short Parkinson's Evaluation Scale (SPES). Kendall's W <0.8 (motor evaluation) was found for two items of the SPES and nine items of the UPDRS. The mean interrater reliability for both scales across all seven centers (seven Kendall's W for seven centers) (Mann-Whitney test) showed no statistical differences between the scales. Spearman's correlations between items of both scales were significant. Factor analysis of the SPES and UPDRS data revealed a four-factor solution that explained approximately 60% of the data. All participating centers found the SPES easier to apply and quicker to complete, when compared with the UPDRS. The results obtained strongly favor the introduction of SPES for clinical practice.

Activities of Daily Living↗
PubMed1996

Arginine and ornithine decarboxylation in rodent brain: coincidental changes during development and after ischemia.

Agmatine, product of arginine decarboxylation, is known to occur mainly in bacteria and plants where it serves as a precursor for the synthesis of polyamines. Recently however, agmatine and arginine decarboxylation were detected in mammalian brain. Here we examined changes in rodent brain arginine decarboxylation during cerebellum development and after global forebrain ischemia and compared them to changes in ornithine decarboxylase, the enzyme catalyzing the first limiting step in polyamine synthesis. The findings suggest that (1) arginine decarboxylation is transiently increased during development and after ischemia in parallel to ornithine decarboxylase activity. (2) Arginine decarboxylation reaction is catalyzed by ornithine decarboxylase. (3) Decarboxylation of both ornithine and arginine becomes more pronounced in membrane fractions, rather than in the cytosol, during brain maturation. (4) During development, ornithine decarboxylase activity is reduced in the cytosol, but increased in the membrane fractions.

Animals↗
PubMed1996

Metabolism of agmatine into urea but not into nitric oxide in rat brain.

Agmatine is a guanidino compound abundant in bacteria and plants where it serves as a precursor for polyamine synthesis. It can interfere with several neurotransmission-related functions and can exert neuroprotective effects after brain injury. Agmatine was recently identified in mammalian brain and its synthesis by arginine decarboxylation was characterized. Its metabolism by the brain is, however, unknown. Here we report evidence indicating that agmatine can be selectively metabolized in the rat brain (cerebellum) into urea and thus, may lead to formation of putrescine, the precursor of polyamine synthesis. In addition, while agmatine can inhibit brain nitric oxide synthase, it did not serve as a substrate for nitric oxide formation.

Agmatine↗
PubMed1996

Accelerated recovery following polyamines and aminoguanidine treatment after facial nerve injury in rats.

Accelerated axon regeneration is of paramount importance for improved functional recovery after motor nerve injuries. Following injury of their axon neurones undergo a series of changes, termed the axon reaction, aimed at survival and regeneration of a new axon. We and others have found that early treatment with exogenous polyamines can enhance neuronal survival and accelerate the rate of axon regeneration and functional recovery after sympathetic and motor (sciatic) nerve injuries. Results of the present study corroborate the previous findings and demonstrate that after facial nerve injury in adult rats, polyamine treatment can accelerate the early phases of motor function recovery (vibrissae movement). Treatment with aminoguanidine, an inhibitor of several oxidation reactions, produced a further improvement at the early phase of functional recovery. In the facial nucleus, the injury-induced transient reduction in the activity of the acetylcholine synthesizing enzyme choline acetyltransferase was not affected by the treatment. After nerve injury in 5-day-old male rats, polyamines and aminoguanidine treatment exerted a minor neuroprotective effect (127.6% surviving neurones compared to control). We conclude that polyamines and aminoguanidine may have therapeutic potential in the acceleration of recovery after nerve injuries.

Animals↗
PubMed1996

Cognitive effects of scopolamine in dementia.

Cholinergic deficiency was postulated to play an important role in the mental decline observed in Alzheimer's (AD), Parkinson's (PD) and multiinfarct (MID) dementia. In the present study, 11 AD, 8 MID and 7 PD patients (DSM III-R diagnostic criteria for dementia) and 9 healthy age-matched controls (CTRL) were given IV 0.5 mg scopolamine (SCO) or placebo (PLA) in random order (double blind) within one week. The Hebrew Short Mental Test (SMT) and Wechsler Memory Scale (WMS) were administered before and after SCO and PLA in each patient. A comparison of SCO vs. PLA utilizing MANCOVA (the covariate being the basal mental performance [BAS] with SMT or WMS) showed that SCO affected all the groups similarly, except for the Wechsler subtest of logic memory which showed larger deterioration in CTRL compared to demented patients. ANOVA and MANCOVA analyses did not distinguish between the three demented groups. SCO administration does not differentiate between demented patients and CTRL and does not enable discrimination between patients with AD, MID and PD. Moreover, some CTRL with still normal cognitive performance, but lower BAS may be more vulnerable to SCO than others. The integrity of the cholinergic system may be responsible for the different sensitivity to SCO challenge.

Aged↗
PubMed1996

Agmatine treatment is neuroprotective in rodent brain injury models.

Agmatine is a naturally occurring guanidino compound, found in bacteria and plants, with several proposed nervous system-related functions suggestive of beneficial effects in central nervous system injury. Here evidence is presented that agmatine can exert potent neuroprotection in both in vitro and in vivo rodent models of neurotoxic and ischemic brain injuries. The cumulative evidence lead us to suggest that agmatine, a relatively nontoxic compound, be tried for potential therapeutic use after neurotrauma and in neurodegenerative disorders.

Agmatine↗
PubMed1996

Electroencephalographic findings with low-dose clozapine treatment in psychotic Parkinsonian patients.

Twenty patients with Parkinson's disease (PD), who developed delusions and psychotic behavior, underwent electroencephalogram (EEG) recordings before and during treatment with low-dose clozapine. Resolution of the psychotic features was observed in all cases. The EEG was unaltered in 15, whereas five patients exhibited increased generalized or focal slowing when compared with the pretreatment tracings. These findings contrast with the high incidence of EEG abnormalities, including epileptiform activity, which are observed when larger doses of clozapine are used in schizophrenic patients, but they underscore that even in low doses, clozapine may cause EEG changes.

Adult↗
PubMed1996

Double-blind comparison of cabergoline and bromocriptine in Parkinson's disease patients with motor fluctuations.

In the present study we compared the efficacy and safety of the new dopamine agonist cabergoline (CBG) with bromocriptine (BCR) in Parkinson's disease (PD). CBG has a very long half-life and can be administered as a single daily dose. Forty-four PD patients with uncontrolled motor fluctuations participated in the study. Patients were randomly and blindly assigned to equivalent doses of either CBG or BCR in addition to preexisting levodopa. Dosage was titrated to optimal, using up to 6 mg of CBG or 40 mg of BCR daily. CBG was given as a single morning dose whereas BCR was administered tid. Sixteen patients were followed for 1 year and 16 additional patients for 6 months. The mean follow-up duration was 9 +/- 5 months. The main effect of both drugs was observed on motor UPDRS scores, rigidity, bradykinesia items, and the percentage of awake hours spent during "on" and "off". In general, the effect of CBG was similar to that of BCR. The percentage of awake hours spent during "on" was higher with CBG as compared with BCR. Adverse events included dyskinesias, orthostatism, confusion, edema, and paresthesias in limbs. These effects were seen at similar frequencies with both drugs. The study shows that CBG given as a single morning dose is at least as efficacious as BCR given tid. CBG is a promising dopamine agonist for the treatment of motor fluctuations in PD.

Aged↗
PubMed1996

Posterior fossa lesions associated with neuropsychiatric symptomatology.

We reviewed 7 cases with posterior fossa structural abnormalities (3 tumors, 2 megacisterna magna and 2 Dandy-Walker syndrome) presenting with neuropsychiatric symptomatology. Derangement in the balance of dopamine, serotonin and noradrenergic networks has been implicated in the pathogenesis of schizophrenia, affective and even personality disorders. Disruption of the cerebellar output to mesial dopaminergic areas, locus coeruleus and raphe nuclei, or deafferentation of the thalamolimbic circuits by a cerebellar lesion may lead to behavioral changes. Seven patients (pts) (comprising 4 men and 3 women with mean age 22 years) were diagnosed as suffering from psychosis (2 pts), major depression (1 pt), personality disorders (2 pts) and somatoform disorders (2 pts) (DSM-IV criteria). Brain CT scan (7 pts) and MRI (4 pts) revealed tumors of the posterior fossa (2 pts), megacisterna magna (2 pts) and Dandy-Walker variant (2 pts). In one patient a IVth ventricle tumor was removed in childhood.

Adult↗
PubMed1995

Decreased dopamine uptake into platelet storage granules in Gilles de la Tourette disease.

The movement disorder of Gilles de la Tourette (GdlT) disease may reflect hyperactivity of the basal ganglionic dopamine system. Since platelets have been suggested as peripheral models for the study of catecholamine neurons, we developed a method to measure the uptake of [3H]-DA into platelet storage granules (PSG). In the present report, PSG were incubated with [3H] DA, and Vmax and Km values were calculated by linear regression analysis (Lineweaver Burke plot). The uptake of DA (0.5-5 microM) by PSG from 18 GdlT patients was significantly lower (p < .0001) compared to 15 controls (Vmax mean +/- SD, 107.5 +/- 42.5 and 265.3 +/- 66.5 fmole/mg protein resp.). The decrease of DA uptake in GdlT may reflect compensatory presynaptic changes that reduce DA activity.

Adolescent↗
PubMed1995

Low-dose clozapine in the treatment of levodopa-induced mental disturbances in Parkinson's disease.

Delusions and other manifestations of psychotic behavior are common side effects in Parkinson's disease (PD) patients chronically treated with dopaminergic drugs. Clozapine, a dibenzodiazepine derivative, is an antipsychotic drug largely devoid of extrapyramidal side effects. We evaluated the effects of low doses of clozapine on the mental and motor functions in PD patients requiring antipsychotic treatment. Twenty-seven PD patients taking dopaminergic drugs and who had psychotic behavior received clozapine at 12.5 to 75 mg/d. Fifteen patients received clozapine for 1 to 11 months (mean, 6.8 months) and seven received it for 12 to 24 months (mean, 18 months). No patient exhibited motor deterioration, and the psychotic features disappeared immediately, allowing discontinuation of clozapine after several months in 10 patients. Fifteen patients are still receiving clozapine and are free of psychiatric symptoms. The clozapine treatment was discontinued after 5 days (25 mg/d) in two patients because of somnolence. No patient developed neutropenia. Clozapine in low doses is effective in the treatment of drug-induced delusions and hallucinations in PD.

Aged↗
PubMed1995

Second generation of dopamine agonists: pros and cons.

Dopamine agonists (DAGs) were first used in patients with moderate or advanced Parkinson's disease (PD). At that time, it was thought that DAGs could replace levodopa (LD) with fewer side effects. However, it soon became clear that while they could not replace LD, they did allow reduction of the dose of LD and diminished its side effects. Since the use of DAGs reduces response fluctuations as well as dyskinesias, there is a tendency to introduce them in the first stages of the disease, trying to delay motor fluctuations. While many DAGs have been developed, only four have been marketed and are used extensively for the treatment of Parkinson's disease: apomorphine, bromocriptine, lisuride and pergolide. In the present chapter, following a review of the "old" DAGs, the experience with three new promising DAGs is reported: cabergoline, ropinirole and pramipexole.

Antiparkinson Agents↗