Search PubMed⌕ Search

Biomedical subjects

I Feinberg

Publications and source records attributed to I Feinberg.

At least 73 records · Page 4Linked to original sources
PubMed1982

Serum vitamin B12, folate, and iron levels in recurrent aphthous ulceration.

Hematologic deficiencies have previously been described in some cases of recurrent aphthous ulceration (RAU). Ninety patients with RAU and twenty-three healthy control subjects were evaluated by complete blood count, serum iron, and total iron-binding capacity, serum vitamin B12, and serum or red blood cell folate. Only three of ninety RAU patients proved to have abnormalities. There were no statistically significant differences between the patient and control populations, and no one in either group had abnormal serum vitamin B12 or serum or RBC folate assays. None of the patients or controls gave a history or symptoms suggestive of iron-deficiency or megaloblastic anemia, and all were without gastrointestinal complaints. These results suggest that hematologic tests other than a complete blood count are not routinely indicated for patients with RAU.

Adolescent↗
PubMed1981

Regulation of ventilation in the obstructive sleep apnea syndrome.

The recent recognition of the sleep apnea syndrome has forced a re-evaluation of the mechanism of hypercapnia and disordered respiratory control in obese patients. Thirteen obese patients with sleep apnea were studied in an attempt to relate the pattern of sleep abnormality and awake ventilatory control to the presence of chronic hypercapnia. Patients with hypercapnia and/or hypoxemia had reduced ventilatory responses to hypercapnic and hypoxic stimulation, respectively. The presence of hypercapnia, however, did not separate the patients with respect to type, duration, or frequency of apneas. The degree of awake chemical drives could not be related to the severity of the sleep apnea phenomenon. However, patients with intact ventilatory control demonstrated augmented ventilation after apneas, which may explain their eucapnic state.

Adult↗
PubMed1979

Flurazepam effects on sleep EEG. Visual, computer, and cycle analysis.

Analysis of sleep effects of flurazepam hydrochloride on four normal subjects confirmed that this drug substantially suppresses both REM and stage 4 sleep. Computer analysis disclosed that delta wave amplitude was greatly reduced by flurazepam. However, low density delta wave activity (ie, stage 2 sleep, which was increased in duration beyond the reduction in stage 4), permitted the number of delta waves and the time they occupied per night to remain at baseline levels. This finding suggests that sedative-hypnotics increase total sleep time by slowing the metabolic processes of sleep so that a longer sleep duration is required for the same biological effects. New observations on the induction times of REM and stage 4 effects are also presented. In general, the distortions in sleep EEG produced by flurazepam qualitatively resemble, but are quantitatively greater than, those produced by barbiturates in equivalent hypnotic doses.

Adult↗
PubMed1979

An optical scan system for encoding and tabulation of visually scored sleep data.

A system for computer-assisted encoding, tabulation and analysis of visually scored sleep data is presented. The main features of the system are: (1) The use of computer-readable optical scan sheets for direct encoding of the sleep data. This eliminates the need for a separate transcription and/or key-punching operation. (2) The development of a visually scored data base, organized by NREM and REM periods, which contains all items of visually scored data indexed by time and/or page of occurrence in the sleep record. The advantages of this new system are: (a) the low cost per night of operation; (b) the facilitation of analysis of cycle phenomena and testing of new hypotheses that would usually involve retabulation of the data; and (c) the facilitation of analysis of real-time correlates of visually scored sleep stages.

Computers↗
PubMed1978

Efference copy and corollary discharge: implications for thinking and its disorders.

Many motor commands in the nervous system are associated with corollary discharges which alter the excitability in both sensory and motor systems. These discharges may assist in the distinction between self-generated and externally produced movements; they also allow (or represent) monitoring of the motor commands before the effector response has occurred. Here, I hypothesize that this mechanism of control and integration is also present in thinking, which as Hughlings Jackson pointed out, may be considered the highest and most complex form of motor activity. I speculate that if corollary discharges are normally part of the motor mechanisms of thought, their derangement could produce many of the symptoms of schizophrenia.

Animals↗
PubMed1977

Flurazepam effects on slow-wave sleep: stage 4 suppressed but number of delta waves constant.

Repeated administration of flurazepam reduced stage 4 sleep (high delta-wave concentration) but produced a greater increase in stage 2 duration so that total sleep time was increased. Computer analysis revealed that the increased amount of stage 2 (low delta-wave concentration) sleep provided a number and duration of delta waves sufficient to offset the loss of delta activity in stage 4. However, the amplitude of the average delta wave was reduced. These results demonstrate the value of direct quantification of delta-wave activity, the variable that underlies visual classification of slow-wave sleep into stages 2 to 4. They also give rise to new hypotheses regarding the relative absence of side effects in spite of profound stage 4 suppression by flurazepam and the mechanisms by which total sleep time is increased by this drug.

Anti-Anxiety Agents↗
PubMed1976

Effects of marijuana extract and tetrahydrocannabinol on electroencephalographic sleep patterns.

Marijuana extract, given in daily doses containing 70 to 210 mg delta-9-tetrahydrocannabinol (THC), induced effects on sleep that were virtually identical to those produced by the same doses of relatively pure (96%) THC. Both drugs reduced eye movements density with some tolerance developing to this effect. Stage 4 tendend to increase with drug administration. Abrupt withdrawal led to extremely high densities of eye movement, increased rapid eye movement (REM) durations, and a sharp but transient fall in stage 4 to baseline levels. These effects may be useful in the elucidation of the pharmacology of sleep. The effects on sleep of THC administration (but not withdrawal) closely resemble those induced by lithium. For this reason, we suggest further studies of THC in affective disorders. Evidence available thus far suggests that THC produces dysphoric symptoms in unipolar but not in bipolar depressed patients; these differences in response may prove of diagnostic value. An adequate therapeutic trial of THC in bipolar depressed patients has not yet been carried out.

Administration, Oral↗
PubMed1975

Effects of high dosage delta-9-tetrahydrocannabinol on sleep patterns in man.

Electroencephalographic readings and eye movement were recorded in experienced marijuana users under placebo and tetrahydrocannabinol (THC). Four subjects were studied for 3 baseline nights, 3 nights under initial dosage of 70 mg/day, the last 3 nights of a 2-wk period of 210 mg/day, and the first 3 nights of withdrawal. Three other subjects were studied only during the latter 2 conditions. Administration of THC significantly reduced eye movement activity during sleep with rapid eye movements (REM) and, to a lesser extent, the duration of REM itself. Withdrawal led to increases above baseline in both measures but the "rebound" effect was greater for eye movement. Stage 4 sleep tended to increase on drug, but this effect was not statistically significant. On withdrawal, stage 4 sleep decreased significantly; this change was marked only on the first withdrawal night. The functional or biological significance of these changes is unclear. Nevertheless, these are the most marked effects of THC on brain electrical activity demonstrated thus far. Since its pattern of effects on sleep appears unique to THC, this drug may prove to be a valuable tool in the elucidation of the pharmacology of sleep. Possible relations between effects on sleep pattern and on behavior are discussed.

Adult↗
PubMed1974

Absence of REM rebound after barbiturate withdrawal.

Administration of three different barbiturates reduced rapid eye movement (REM) sleep. Drug withdrawal led to a return to baseline REM] values without significant overshoot. Similar results are observed with administration of benzodiazepines in pharmacologically equivalent dosages; therefore, a distinction between these two drug classes on the basis of withdrawal effects on the sleep electroencephalogram appears unwarranted. Further investigation is required determine why high REM levels are sometimes associated with the withdrawal of sedative-hypnotic agents.

Amobarbital↗