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Biomedical subjects

K Syndulko

Publications and source records attributed to K Syndulko.

66 records · Page 4Linked to original sources
PubMed1980

Human neurologic function and the aging process.

Sixty-one normal men whose ages ranged from 20 to 80 years were evaluated on two occasions by means of a comprehensive series of 128 instrumented tests of neurologic function. The tests measured cognition, vision, strength, steadiness, reactions, speed, coordination, fatigue, gait, station, sensations, and tasks of daily living. The reliability of each test measured was determined, and any measure found unreliable (r less than or equal to 0.41) was not further analyzed. Significant age-related linear decreases were found for almost all neurologic functions. The declines over the age span varied from less than 10 percent to more than 90 percent for different functions. For the upper extremities, the largest declines (greater than 50 percent) were in hand-force steadiness, speed of hand-arm movements, and vibration sense; for the lower extremities, the largest declines were in one-legged balance with eyes closed and in vibration sense. For 13 of 14 tests in which significant dominant body-side effects were found, larger re-testing 7-10 days later, the subjects improved their scores by more than 5 percent on only 17 tests, 9 of which concerned the activities of daily living. No significant differential learning effects were found across age groups. The results point to the importance of developing a data bank on age-based neurologic function so that therapeutic effects can be evaluated in terms of age- and sex-matched normal functioning.

Adult↗
PubMed1980

Multiple sclerosis de novo CNS IgG synthesis: effect of ACTH and corticosteroids.

ACTH gel and corticosteroids were given to 28 clinically definite multiple sclerosis (MS) patients to determine whether de novo central nervous system (CNS) IgG synthesis (rate and cerebrospinal fluid [CSF] IgG oligoclonal bands) could be eradicated. The most effective treatments were ACTH gel and ACTH gel followed by prednisone, all 11 patients had a significant reduction in rate (p < 0.05), which became normal in eight patients (< 3.3 mg per day). In order of effectiveness, the other drugs used were: dexamethasone or prednisone given orally, and hydrocortisone administered intrathecally. For most treatments, reduction of the rate of CNS IgG synthesis occurred within days and persisted for months after cessation of treatment. The MS CNS immune reaction was not eradicated when IgG synthesis rate became normal, because CSF IgG oligoclonal bands persisted. None of the chronic progressive, severely disabled patients demonstrated significant change in neurologic function or persistent adverse effects.

Adrenal Cortex Hormones↗
PubMed1980

Multiple sclerosis: measurement and validation of central nervous system IgG synthesis rate.

An empirical formula has been developed to calculate the de novo rate of synthesis of IgG in the central nervous system (CNS), based on physiologic principles that govern the passage of albumin and IgG across the blood-brain barrier (BBB). To validate the formula, radiolabeled IgG and albumin from pooled normal sera were followed from the blood to the cerebrospinal fluid (CSF) over 21 days in nine patients with definite multiple sclerosis (MS). IgG synthesis rates were calculated by the isotope exchange method and compared to values obtained with the empirical formula. There was excellent concordance, from a low rate of synthesis of 5 mg per day to a high rate of 120 mg per day. A double radiolabeled IgG experiment in two patients showed that the MS BBB processed normal serum IgG in the same way as IgG derived from autologous MS serum. Accordingly, the empirical formula, which requires only one sample of CSF and matched serum, can reliably and validly estimate the de novo rate of IgG synthesis in CNS of patients with MS.

Blood-Brain Barrier↗
PubMed1979

Cortical slow negative waves following non-paired stimuli: effects of modality, intensity and rate of stimulation.

Using a simple stimulus counting task, negative after-waves following single (unpaired) stimuli were investigated under a variety of stimulus conditions. Responses were obtained to tones at 3 intensities, to light flashes at 3 intensities, and to tones at 3 rates of presentation. The acoustic stimuli led to a negative after-wave that peaked at frontal sites around 500 or 600 msec, and then trailed off to a more central scalp representation. This negative after-wave was increased in amplitude by slowing the rate of stimulus presentation. In comparison, no appreciable or sustained after-wave was elicited by visual stimuli. No significant effects in the negative after-wave were associated with intensity, either for visual or for acoustic stimuli. When analyzed by Principal Components Analysis, the negative after-waves were shown to comprise in all cases two underlying factors, although the factors contributed less to the total wave form for visual stimuli than for acoustic stimuli. Two interpretations for the negative after-wave were contrasted, one considering it to be an integral feature of the auditory evoked potential. A second interpretation, more compatible with the data obtained here, links the negative after-wave with non-specific activation processes.

Acoustic Stimulation↗
PubMed1976

Brain wave components of the contingent negative variation in humans.

In a contingent negative variation paradigm with two stimuli paired at an interstimulus interval of 4 seconds, two distinct waveforms having functional and topographic differences are observed. An early wave is maximal over the frontal cortex and is elicited by the warning stimulus. A later wave, maximal over the motor cortex, precedes the imperative stimulus and is identified with preparation for motor response.

Brain↗
PubMed1975

Psychophysiology of sociopathy: electrocortical measures.

The CNV, visual AEP and resting EEG were analyzed in sociopaths and controls matched for age and sex. Twenty-seven male sociopaths were selected by psychiatric interview and special rating scale, restricted to Shipley-Hartford IQs of 115-145 and separated into young (x = 20.5 yr) and older (x = 35.3 yr) age groups. Subjects participated in forewarned reaction-time tasks in which the imperative stimulus was either an innocuous or noxious tone that the subject escaped by pressing a response key. Sociopaths and controls did not differ in reaction time, vertex and occipital AEP amplitude or latency, and power spectral density of the EEG. Contrary to previous findings, there also were no significant differences between sociopaths and controls in overall CNV amplitude or topography. However, while most controls showed increased CNV amplitude in the noxious tone condition as compared to the innocuous tone condition, older sociopaths showed no change, or decreased amplitudes.

Acoustic Stimulation↗
PubMedDate not supplied

Aversive conditioning in the sociopath.

Results of two experiments on differential conditioning of the skin conductance (SCR) in sociopaths and normal control subjects are described. In the first experiment it was found that an equal number of sociopaths and control subjects were aware of the conditioning contingency. However, only the normal subjects displayed reliable differential SCR conditioning. Sociopaths showed a dissociation between verbal learning and conditioning of a physiological change. The second experiment examined the differential conditioning of normal subjects and sociopaths in partial remission. The number of aware subjects in the two groups did not differ. Aware subjects in both groups showed differential SCR conditioning. Differential conditioning in sociopaths did not persist over trials as it did in control subjects. A deficiency in ACTH 4--10 as well as neurological dysfunctions were considered possible factors in the etiology of sociopathy. Further research on the relation of neuropeptides to the etiology and treatment of sociopathy is suggested.

Adrenocorticotropic Hormone↗