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Biomedical subjects

D L Levy

Publications and source records attributed to D L Levy.

14 recordsLinked to original sources
PubMed1978

Vestibular responses in schizophrenia.

In a study of vestibular responses to caloric stimulation that controlled opportunity for fixation and state of alertness, we evaluated previous findings of diminished nystagmus in schizophrenia. We failed to replicate earlier reports in these respects: (1) None of the psychotic patient groups, when compared with normal controls, showed lower response intensity, latency, or culmination time of the nystagmic response. (2) The schizophrenic groups did not manifest a prevalence of clinically significant asymmetry. We did, however, observe that chronic deteriorated schizophrenics and recent schizophrenics have significantly greater dysrhythmic responses. This diminished orderliness of nystagmus may explain previous reports of absent or diminished nystagmus in the schizophrenics. The results are not compatible with peripheral vestibular disease in schizophrenia, but they may reflect state-related phenomena consistent with disturbances in alertness, which are not necessarily voluntary or motivational in origin.

Acute Disease↗
PubMed1977

Visual interference on vestibular response. A case study.

Eliminating opportunity for visual fixation as well as providing for the maintenance of an optimal degree of a patient's mental alertness are necessary for a valid assessment of nystagmic response to caloric stimulation. Controlling only for alertness can result in suppressed, absent, or dysrhythmic nystagmus. Data from four normal patients dramatically illustrate the suppressing effects of fixation opportunity despite an alert state. A new clinical instrument for obtaining optimal control over visual influences is described.

Adult↗
PubMed1977

Abnormal-pursuit eye movements in schizophrenia. Evidence for a genetic indicator.

Disordered smooth-pursuit eye movements occur in a high percentage of schizophrenic patients and their first-degree relatives. A Test of the hypothesis that these disorders represent a genetic indicator of schizophrenia was undertaken by testing pursuit eye movements in a sample of monozygotic and dizygotic twins discordant for clinical schizophrenia. Deviant eye tracking is significantly concordant within monozygotic twin pairs, and less so with dizygotic twin pairs discordant for schizophrenia. A genetic interpretation is consistent with these results.

Adult↗
PubMed1976

Smooth pursuit eye movements, attention, and schizophrenia.

In previous studies, smooth pursuit eye movements (SPEM) have been shown to be disordered in about 70% of schizophrenics and about 45% of their first-degree relatives. In this report, the role of attention in these eye movements is addressed in three experiments (using as subjects schizophrenics, their first-degree relatives, and normals administered chloral hydrate) that recruit focused attention to the task. These studies show that voluntary attention in the form of inattention, "heedless negligence," or failure to cooperate, is not the specific attentional quality that is disordered in SPEM of schizophrenics and their relatives. Rather, the data both indicate that nonvoluntary attending is specifically disordered in these persons, and implicate a neurophysiological substrate that can be described as a failure of inhibitory, synchronizing integrating systems which may be located in the brain stem.

Adult↗
PubMed1976

Persistent brow presentation: a new approach to management.

When the fetal vertex is extended on the spinal column and the brow becomes the presenting part, it is termed "brow presentation." Persistent brow presentation occurs when there is no spontaneous conversion after the onset of active labor. Since there is a risk in the vaginal delivery of such fetuses, it should not be attempted where there is known maternal disease or evidence of acute or chronic intrauterine fetal distress. During labor, cesarean section is indicated if there is cephalopelvic disproportion, if the fetal head is not in the frontoanterior position, if there is abnormal labor, or if there is evidence of fetal distress. Continuous lumbar epidural anesthesia should be given, and only manual conversion is used. The fetus is monitored continuously.

Anesthesia, Epidural↗
PubMed1976

47,XXX karyotype obtained by amniocentesis.

A 29-year-old pregnant patient, gravida 4, para 3, sought genetic counseling because of a daughter who had Down's syndrome. Amniotic fluid obtained by amniocentesis indicated the fetal karyotype to be 47,XXX. The pregnancy was terminated and the karyotype was confirmed by typing venous blood from the fetus and the finding of double Barr bodies in the histologic sections of fetal tissue.

Abortion, Induced↗
PubMed1976

The specificity of gonadotropin binding by the human corpus luteum.

The specificity of gonadotropin binding was studied in fresh and frozen human corpora lutea. Ovine, bovine, and porcine luteinizing hormone (LH) competed with 125I-labeled human LH (125I-hLH) and 125I-labeled human chorionic gonadotropin (125I-hCG) for binding to tissue receptors in homogenates of human corpora lutea frozen for 3 to 12 months. In contrast, oLH, bLH, and pLH competed minimally for 125I-hLH and 125I-hCG binding sites in homogenates of fresh human corpora lutea. Ovine follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) did not compete in homogenates of fresh or frozen tissue. Competition of oLH and hCG for 125I-hCG binding sites at several dose levels in a homogenate of a fresh corpus luteum was studied. One hundred micrograms of oLH and ten nanograms of hCG gave an equivalent competition--a 10,000-fold difference in competitive potency. Only hCG competed with 125I-hCG for binding when the competition of oLH, bLH, pLH, oFSH, oTSH, hCG and hCG subunits, and hCG were compared at the 10-mug level in a homogenate of fresh human corpus luteum. The binding of 125I-labeled homologous human hormones by the corpus luteum was examined in a limited fashion. 125I-Prolactin did not bind to preparations of fresh stroma from a patient with polycystic ovaries nor did it bind to three separate preparations of fresh corpora luteum which did bind 125I-hCG. 125I-hTSH did not show significant binding to a fresh human corpus luteum preparation which did bind 125I-hCG. These studies indicate that the gonadotropin receptor of the fresh human corpus luteum possesses a unique species specificity and illustrate the importance of working with human corpora lutea in their most native state.

Binding, Competitive↗
PubMed1975

Smooth-pursuit eye movements, and diazepam, CPZ, and secobarbital.

This study examined the effects on smooth-pursuit eye tracking of single doses of CPZ (0.667 and 1.334 mg/kg), diazepam (0.071, 0.142, and 0.284 mg/kg), and secobarbital (100 mg). Only the barbiturate significantly affected the ability to follow a moving target with smooth-pursuit eye movements. In repeated testing of a single subject, 130 mg of secobarbital disrupted smooth-pursuit movements at least until 24 hrs after ingestion.

Adult↗