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Biomedical subjects

A D Korczyn

Publications and source records attributed to A D Korczyn.

At least 19 recordsLinked to original sources
PubMed1992

Decreased (3H) quinuclidinyl benzilate binding to lymphocytes in Gilles de la Tourette syndrome.

In spite of an unknown pathophysiology, it has been suggested that central dopaminergic hyperactivity exists in Gilles de la Tourette syndrome (TS). Cholinergic influences have also been postulated as a dopaminergic-cholinergic balance seems to be important in other movement disorders. If TS is due to alterations of cholinergic activity, this may also be expressed at postsynaptic levels. Recently, we showed that circulating lymphocytes may serve as useful peripheral markers reflecting induced alterations or inherent changes in muscarinic receptors in the central nervous system (CNS). In the present study, we compared the muscarinic binding characteristics in peripheral lymphocytes as measured by (3H) quinuclidinyl benzilate [(3H)-QNB] in 27 unmedicated TS patients, against 22 healthy (age and gender-matched) controls. B(max) and Kd values were determined using Lineweaver-Burke plots. The mean B(max) values in nontreated TS patients was markedly and significantly lower than in controls (10.59 +/- 8.4 versus 40.16 +/- 9.2 fmole/10(6) cells, p less than 10(-6), while Kd values were similar in both groups. Our findings suggest that changes in cholinergic receptors may play a role in the pathophysiology of Tourette syndrome.

Adolescent↗
PubMed1992

Demyelinating peripheral neuropathy in Creutzfeldt-Jakob disease.

We describe 2 patients of Jewish Libyan descent, who presented with a clinical syndrome compatible with Creutzfeldt-Jakob disease and who were found to have a mutation of codon 200 in the prion protein. The patients developed symptoms and signs of peripheral nerve involvement diagnosed by electrodiagnostic and histopathological studies as demyelinating neuropathy. This may be a rare manifestation of Creutzfeldt-Jakob disease.

Action Potentials↗
PubMed1992

Topographic distribution of the periodic discharges in Creutzfeldt-Jakob disease (CJD).

A characteristic EEG abnormality in patients with Creutzfeldt-Jakob disease (CJD) consists of periodic high voltage bilateral diphasic or triphasic sharp waves widely distributed over both hemispheres. The mechanism underlying these electrographic manifestations is, however, unclear. To increase our understanding of these phenomena, we have employed the technique of microcomputer brain mapping, to analyze the electrical fields of the bilaterally-distributed complexes in four patients with CJD. Ten generalized discharges were studied in each patient. The EEG analysis demonstrated variability in the area of onset as well as the field maxima between the different complexes among patients as well as between discharges in each patient. The generalized pattern seen in routine EEG was clearly shown on brain mapping to be not strictly generalized from onset, nor bilaterally symmetrical. These findings may suggest multifocal areas of onset of the generalized discharges, or alternating pathways of activation of the cortical areas by a subcortical pacemaker.

Aged↗
PubMed1992

Pupillary responses and blink reflex in myotonic dystrophy.

We have studied pupillary responses to parasympathetic and sympathomimetic agents, pupillary cycle time and the electrophysiology of the blink reflex in 18 patients with myotonic dystrophy. The response of the iris to dilute pilocarpine and phenylephrine did not indicate pharmacologic supersensitivity. Pupillary cycle time was prolonged in nine of the 18 patients. Ipsilateral R1 blink reflex latencies were normal in all cases, and bilateral R2 were normal in 16 of the 18 patients. These results do not support either autonomic or brainstem dysfunction in the majority of patients with myotonic dystrophy. In 50% of the patients the results are compatible with smooth muscle involvement of the iris.

Adult↗
PubMed1992

Efficacy of memantine, an NMDA receptor antagonist, in the treatment of Parkinson's disease.

Memantine is a 1-amino-adamantane derivative which has been proposed to be useful in the treatment of Parkinson's disease. Its beneficial effect has been related to its novel properties as an NMDA receptor blocker which can neutralize the effect of glutamate at striatal and subthalamic levels. In the present study, conducted in an open-fashion, 14 parkinsonian patients with motor fluctuations taking L-dopa, were given a supplement of memantine 30 mg/day. After one month, 10 patients completed the treatment (4 discontinued it due to abdominal pain, psychomotor agitation, confusion and dizziness). In 5 patients, the main parkinsonian features improved significantly (1 point or more on the Webster scale). In 6 patients, "off" episodes improved (from daily mean of 273 minutes, to 172 minutes). In summary, memantine addition to parkinsonian features, could form a basis for novel therapeutic strategies directed to neutralize the effects of glutamate at striatal and subthalamic levels.

Aged↗
PubMed1992

Kinematic analysis of upper limb trajectories in Parkinson's disease.

The purpose of this study was to analyze the kinematic properties of upper limb trajectories in Parkinson's disease (PD) patients and to investigate the role of visual feedback from the moving limb. Beyond the characteristic bradykinesia, PD patients differed from controls by generating hand trajectories with asymmetrical velocity profiles that lacked smoothness and were composed of a short initial accelerative phase, followed by a prolonged interval composed of alternating decelerative and accelerative phases. In both groups, the reaction times for movements directed away from the body were longer than for movements directed toward the body; this effect was accentuated in PD. In both groups, initial peak accelerations were significantly larger for distally as compared to proximally directed movements. In the absence of visual feedback from the limb a deterioration in the accuracy of reaching the target was observed in both control and PD patients only for distally directed movements. However, this deterioration and the effect of target location on final accuracy was substantially larger in PD. Taken together, our study suggests that in PD visual information is continuously relied upon for ongoing movement correction, therefore accentuating the bradykinesia. The deficit in final accuracy in the absence of visual feedback reflects the important role played by the basal ganglia in sensorimotor integration.

Acceleration↗
PubMed1992

DSM-III-R criteria for primary degenerative dementia and multi-infarct dementia [corrected].

Primary degenerative dementia (PDD) and multi-infarct dementia (MID) are the two most common categories of cognitive decline in old age. The definitions of these two clinical entities are currently based on clinical evaluation and on the exclusion of other underlying causes, and still lack a consensus. The DSM-III-R criteria are widely used for the diagnosis of dementia. However, their role in the differentiation between PDD and MID has not been thoroughly examined. A consecutive series of 98 demented patients who met the DSM-III-R criteria for dementia were admitted to a clinical study. Upon evaluating their type of dementia according to these criteria, 53 patients could not be diagnosed either as having PDD or MID. The DSM-III-R criteria for these two types of dementia are critically reviewed. Proposed modifications, aimed at refining their differential diagnostic role, are presented, enabling better allocation of demented patients into PDD, MID, or intermediate groups.

Aged↗
PubMed1992

Naproxen sodium versus ergotamine tartrate in the treatment of acute migraine attacks.

A double-blind parallel study compared the efficacy and safety of naproxen sodium (NPX) and ergotamine tartrate (ERG) as abortive therapy for acute headache in 79 patients with classical or common migraine. The design study was of the double-blind design. Forty-two patients completed the study. Discontinuation of treatment was generally due to lack of efficacy or adverse reactions. NPX was significantly better than ERG in the overall efficacy of treatment rated by the patients (p less than 004). NPX was comparable to ERG in reducing the severity and duration of the headache and its associated symptoms. In classical migraine, NPX was better than ERG in alleviating the severity of headache. Patients in the NPX group tended to use less rescue medication. There was no significant difference in the frequency of side-effects reported by the patients under NPX or ERG. This study demonstrates that NPX is as safe as ERG, and somewhat more effective in acute migraine attacks (although the difference is not statistically significant) and that migrainous patients tend to prefer NPX to ERG in treating their acute migraine headaches.

Acute Disease↗
PubMed1992

Heparin in the treatment of acute stroke.

It has been over 50 years since the first publication on the clinical use of heparin for the prevention of thrombosis appeared. The indications for heparin use have been well defined in several medical fields, but there is still much debate and confusion as to the indications and possible benefits of this treatment in neurology. This article reviews the theoretical considerations regarding heparin use, various side effects, and indications for administration.

Cerebrovascular Disorders↗
PubMed1991

Carpal tunnel syndrome: a complication of idiopathic torsion dystonia.

Carpal tunnel syndrome (CTS) is usually an idiopathic disorder. Certain occupations that require frequent flexion movements of the hand at the wrist are recognized as precipitating the development of CTS. Dystonia can cause similar excessive movements at the wrists. We report the clinical and electromyographic findings of two patients with idiopathic torsion dystonia (ITD), with frequent flexion postures of the wrists, in both of whom typical CTS developed in the more involved hand. It is concluded that nerve entrapment such as CTS has to be considered a possible complication in patients with ITD and other motor control disorders.

Adult↗
PubMed1991

Creutzfeldt-Jacob disease associated with the PRNP codon 200Lys mutation: an analysis of 45 families.

200Lys mutation in the human PRNP coding region has been identified in 45 of the 55 CJD-affected families thus far presented to our NIH laboratory. These codon 200Lys families have a total of 87 patients, and originate from 7 different countries: Slovakia, Poland, Germany, Tunisia, Greece, Libya, and Chile. Forty-seven patients were neuropathologically verified, and brain tissue from 14 patients transmitted disease to experimental primates. The mutation was found by direct sequencing in 4 patients, and it was detected by restriction endonuclease analysis with BsmA 1 and/or the single nucleotide extension reaction in 36 other patients and 45 of 109 first degree relatives (1 parent, 14 siblings, and 30 children). The mutation is associated with all known geographical clusters of CJD (Slovakia, Libyan Jews, Chile) in which the annual mortality rate is tens or hundreds of times higher than the world average of 1 per million. All patients originating from the cluster areas carried the mutation, but it was seen in only 1 of 103 unrelated control individuals from the same areas, and in none of 102 controls from other areas, indicating a strong association between the mutation and disease. The penetrance of the mutation was estimated to be 0.56. Branches of some families migrating from cluster areas to other countries continue to have CJD over several generations, suggesting that CJD in these families is a genetic disorder, in which the 200Lys mutation is responsible for the disease.

Africa↗