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Biomedical subjects

K Lifshitz

Publications and source records attributed to K Lifshitz.

15 recordsLinked to original sources
PubMed1991

Effect of extended depot fluphenazine treatment and withdrawal on social and other behaviors of Cebus apella monkeys.

To examine whether or not prolonged exposure to a depot neuroleptic has either residual or "tardive pathological" effects on normal behavior, 38 Cebus apella monkeys were observed daily for 108 weeks. The issue of stress influencing such effects was also addressed. During weeks 25-48 half of the monkeys received 0.22 mg/kg fluphenazine decanoate, IM, every 3 weeks, with the dose increased to 0.33 mg/kg during weeks 49-72. Behavioral measures were combined to form composite behavioral variables which quantify four major aspects of behavior: self- and environment-directed behavior, affiliation, aggression, and normal locomotor activity. Mean plasma fluphenazine levels at 48 h post-injection were 0.13 (+/- 0.03) ng/ml for injections 3-8 and 0.24 (+/- 0.07) ng/ml for injections 11-16. The pre-study null hypothesis that the four major aspects of behavior would not be adversely affected by this treatment during the drug-discontinuation phase of the study (weeks 73-108) was not statistically negated. There were highly significant decreases in self- and environment-directed behaviors and affiliation during the treatment periods, implying that treatment may contribute to the negative symptoms of treated schizophrenics. Stress reduced the above effects. Aggression showed some increase during early drug discontinuation, accentuated by stress. Recovery of normal (baseline) behavioral scores began by week 7 after the last treatment. Mild (bucco-lingual) tardive dyskinesias persisted in 30% of the animals for a prolonged time.

Animals↗
PubMed1990

A computer workstation for clinical medicine.

New computer tools for physicians, nurses, and the medical care team will become common in the 1990s. This paper describes a clinical workstation (CWS) development project that uses new technology that moves the technical support for medical decision making from the computer room to the nursing station. Collection, processing, and display of clinical information including patient identification, laboratory, and radiology results and current medications are carried out in the environment of a multi-windowed computer workstation. Easy access to automated medical literature databases from the workstation is also provided. This pilot project has successfully demonstrated a CWS operating on an acute general neurology and neurosurgical inpatient nursing unit and a critical care unit at The Johns Hopkins Hospital.

Baltimore↗
PubMed1987

Event-related EEG field changes in aroused subjects and schizophrenic patients.

The average auditory event-related potential (AAEP) to nonmeaningful stimuli has maximum vertex negative and positive amplitudes at about 100 and 200 msec, respectively. This "vertex potential" was studied under different arousal conditions in 15 normal men and 30 chronic schizophrenic subjects using the average event-related vector electro-encephalogram (AEVE) and the AAEP. The AEVE shows the path, in time, of the event-related electric field vector. To produce intramodal arousal, normal subjects also had EEG recordings made during the random sounding of a loud bell. AAEPs and AEVEs were calculated for spontaneous changes in arousal, as indicated by EEG delta band power. Bell arousal of the normal subjects increased the AAEP and AEVE measures of vertex potential maxima, thus increasing the existing differences between normals and schizophrenics. Analysis of the AEVE path indicates that arousal increased the electric field intensity, but probably did not alter, within the first 250 msec, the spatial distribution of the cortical EEG generators. After 250 msec, a reorganization of generators was indicated for the three groups. Schizophrenics differed from normals in the decreased maximum intensity of the vertex negative electric field, which was indicated by both the AEVE and AAEP.

Adult↗
PubMed1987

Long-term replicability of EEG spectra and auditory evoked potentials in schizophrenic and normal subjects.

The spectral characteristics and average, auditory evoked potentials (AEPs) were determined from EEGs repeatedly recorded over a span of several years. Data from a vertex lead is presented for 4 chronic schizophrenic patients and 5 normal subjects. Measurements were made under identical conditions. For each subject characteristic spectra and AEPs were exhibited despite the passage of time. Patients had recordings performed both on and off antipsychotic medication. While receiving antipsychotic medication the patients' EEG spectra showed an increase in alpha activity. Less consistently there was a decrease in delta or an increase in beta activity; theta activity was unchanged. These latter effects are different from those generally reported for an acute antipsychotic dose and may be more representative of antipsychotic effects (which occur after days or weeks of treatment). Psychopathology tended to be inversely related to alpha power, the magnitude of the AEP N100, and medication.

Adult↗
PubMed1980

Average evoked potentials and amplitude modulation.

Average auditory evoked potentials (AEPs) to amplitude modulated (AM) linear voltage ramps within a limited intensity range were investigated in a group of 4 subjects. Increasing linear voltage ramps evoked the familiar vertex potential; the average AEP to decreasing ramps was difficult to measure because of its small amplitude. The amplitude of the average AEP to increasing ramps depended on the tone that preceded it. The average amplitude was largest when the tone preceding the onset of the ramp was constant and decreased in amplitude when the slope of the preceding tone deviated from zero either in the positive or negative direction with the positive slope having the more marked attenuating effect. The standard deviation (S.D.) of the distributions of reaction times to stimulus onset correlated negatively with the average AEP amplitude. The attenuation of the averaged AEP appeared to be related to the uncertainty of the subjects as to when the various types of stimuli occurred. The above findings on AM ramp stimuli closely parrellel our previously reported findings on frequency modulated ramp stimuli.

Acoustic Stimulation↗
PubMed1978

Averaged evoked potentials and frequency modulation.

Frequency modulated (FM) auditory stimuli result in average vertex potentials similar to the usual auditory average evoked potential (AEP). For stepwise increase or decrease in tone frequency the AEPs are similar. For FM stimuli modulated by pulses of different durations 'on' responses are evoked by the transition of the stimulus from the longer duration to the shorter duration frequency tone while 'off' responses result when the frequency transition is from the shorter to the longer duration tone. Ramp modulation of the stimulus frequency results in average evoked responses; the amplitude of these responses is proportional to the slope of the ramp as well as the frequency of the tone that precedes the ramp. Thus, if the tone preceding the ramp is also a ramp but of smaller slope the AEP is attenuated and with sufficiently large slope the AEP can be completely extinguished. No AEPs were obtained at the offset of ramp modulated stimuli. The standard deviation (S.D.) of the reaction time (RT) distributions to stimulus onset indicate that the AEP amplitude is inversely proportional to the S.D. values. Thus, the attenuation phenomena appeared to be related to the uncertainty of the subject as to the exact time the stimulus occurred, both of which seem to be the result of sensory difficulty to the type of stimuli used. AEPs to negative ramps were smaller than AEPs to positive ramps; this may be on account of the psychological inequality between the stimuli.

Acoustic Stimulation↗