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Biomedical subjects

D L Levy

Publications and source records attributed to D L Levy.

At least 55 records · Page 3Linked to original sources
PubMed1989

Perceived aluminum-related disease in a dialysis population. A report from the End-Stage Renal Disease Network 28.

A survey to assess the perceived prevalence of aluminum-related disease was conducted by the Medical Review Board of the End-Stage Renal Disease Network 28 from 1986 to 1987. Responses were obtained for 855 of 3000 patients on dialysis representing 17 of 39 participating dialysis units within the network. Almost 40% of the patients surveyed had been receiving dialysis therapy for over 3 years. Patients on hemodialysis (83% of the study group) had the water used to prepare the dialysate pretreated. Serum aluminum determinations were obtained in 240 (28%) of the 855 patients; other methods of assessing body aluminum burden were performed in less than 10% of the survey population. When obtained, elevated serum aluminum measurements were more likely to be found with each year patients were given dialysis and with each year patients were treated with oral aluminum gels. With the exception of patients with bone pain, clinical signs and symptoms did not correlate with elevated serum aluminum. However, the prevalence of muscle weakness, bone pain, fractures, and dementia in the survey group did correlate with years on dialysis and/or years receiving oral aluminum gels. Data gathered from this survey are consistent with the view that signs and symptoms suggestive of an increased body aluminum burden occur in the minority of patients on dialysis. Nevertheless, patients at risk for aluminum intoxication (years on dialysis, years receiving gels, patients with clinical signs) may not be adequately identified.

Aluminum↗
PubMed1988

A single dominant gene can account for eye tracking dysfunctions and schizophrenia in offspring of discordant twins.

Eye movement dysfunctions (EMDs), detectable during smooth pursuit, occur in a majority of schizophrenics and in 45% of their first-degree relatives. Previous data suggest that they represent a biologic marker for schizophrenia. To determine the mode of transmission of the schizophrenia-EMD complex, the eye movements of offspring of monozygotic and dizygotic twins were recorded. One group of twins was discordant for schizophrenia; the other group for manic depression or reactive psychosis. The data suggest that EMDs and at least some schizophrenias can be considered expressions of a single underlying trait that is transmitted by an autosomal dominant gene.

Affective Disorders, Psychotic↗
PubMed1988

Lower limb movements and urologic function in fetuses with neural tube and other central nervous system defects.

Lower limb movements and urologic systems were evaluated by prenatal ultrasound in 120 fetuses with either neural tube defects or intracranial anomalies. Despite anticipated major lower extremity and bladder dysfunction, lower limb movements were seen in 100% of the fetuses with anencephaly and encephaloceles, 93% with isolated spina bifida, 60% with complex spina bifida and 90% with abnormal intracranial findings. In all the cases except those with cloacal exstrophy, fetal bladder and collecting systems appeared normal. Therefore, fetal lower limb movements and urinary tract integrity appear to have no diagnostic or prognostic value in fetuses with neural tube defects or other central nervous system anomalies. These diagnoses can only be made by direct ultrasound observation of the lesion itself.

Anencephaly↗
PubMed1987

Fetal sacrococcygeal teratoma.

Early prenatal diagnosis of fetal sacrococcygeal teratoma (SCT) has enabled the perinatal team to institute management of this condition during the perinatal period. We report 2 additional cases to our previous 27 cases including 1 which represents the earliest diagnosis of SCT. Fetal SCT behaves in a different manner than neonatal SCT. In utero manipulation of fetal SCT may be possible if diagnosis is made during the second trimester.

Adult↗
PubMed1987

Eye movements in schizophrenia.

Smooth pursuit and other eye movements were quantitatively studied in patients with chronic schizophrenia to characterize the pattern and severity of eye movement abnormalities in this disorder. Twenty-one patients with schizophrenia, 13 patients with other psychiatric disorders (manic-depressive psychosis, schizoaffective disorder, depression and obsessive-compulsive disorder), and 19 normal subjects were studied. Horizontal eye movements were recorded with DC electro-oculography and analyzed by an online computer system. Eye velocity and closed-loop gain of pursuit, optokinetic nystagmus (OKN), vestibulo-ocular response (VOR) and visual-vestibular interactions were calculated. The latency, accuracy and peak velocity-amplitude relationships of voluntary saccades were measured. The group mean gains of pursuit and OKN of the schizophrenic patients were significantly lower than those of the normal subjects. Suppression of the VOR by fixation was impaired, and the latency of saccades was prolonged. However, the differences in group mean values were small in magnitude, and the frequencies of outliers among the schizophrenic patients were low. The patients with other psychiatric disorders had a similar pattern and severity of eye movement abnormalities. The frequency and severity of eye movement abnormalities in schizophrenic patients are lower than those indicated by previous studies that used different techniques of analysis.

Adolescent↗
PubMed1986

An analysis of the obstetric outcome of 125 consecutive pregnancies conceived in vitro and resulting in 100 deliveries.

One hundred twenty-five consecutive pregnancies conceived in vitro resulted in 100 deliveries of 115 babies. There were 23 clinical abortions (18.4%) and two tubal pregnancies. During the same interval 30 preclinical pregnancies occurred, but these pregnancies did not progress. There were 26 multiple pregnancies (37.1%) before the twelfth week; these reduced spontaneously to 14 (22.2%) multiple births at delivery. Eight infants were delivered prematurely, and three of these died. Three babies had some congenital abnormality. Vaginal bleeding occurred during pregnancy in 59% of patients. Cesarean section was the method of delivery in 56% of patients. Other complications of pregnancy were similar to those of comparable populations.

Abortion, Spontaneous↗
PubMed1985

Pharmacologic evidence for specificity of pursuit dysfunction to schizophrenia. Lithium carbonate associated with abnormal pursuit.

Conflicting findings regarding the prevalence of abnormal smooth-pursuit eye movements in patients with major affective disorders call into question the specificity of impaired smooth-pursuit eye movements to schizophrenia. We report that pursuit is impaired in 88% of lithium carbonate-treated affective disorder patients whose pursuit was normal prior to receiving this drug. Over half of lithium carbonate-treated affective disorder patients in remission also showed impairment of smooth-pursuit eye movements. In conjunction with recent prevalence data on family members of psychiatric patients, the findings support the specificity of abnormal pursuit as a biological trait associated with schizophrenia, but not with the major affective disorders. The mechanisms by which lithium carbonate impairs pursuit are discussed.

Adult↗
PubMed1985

Oral ritodrine and preterm premature rupture of membranes.

A prospective randomized study was performed to determine whether or not oral ritodrine therapy significantly prolonged the latent period in patients with prematurely ruptured membranes. Compared with a control group of similar patients, those treated had a significantly prolonged mean latent period. In addition, 47.6% of the treatment group versus 14.2% of the control group had a latent period of more than one week.

Birth Weight↗
PubMed1984

The future of measles in highly immunized populations. A modeling approach.

Little is known about how an intensive measles elimination program changes the overall immune status of the population. A computer model was created to study the effect of the measles elimination program in the United States on the number of susceptibles in the population. The simulation reveals that in the prevaccine era, approximately 10.6% of the population was susceptible to measles, most of whom were children less than 10 years of age. With the institution of the measles immunization program, the proportion of susceptibles in the population fell to 3.1% from 1978 through 1981, but then began to rise by approximately 0.1% per year to reach about 10.9% in the year 2050. The susceptibles at this time were distributed evenly throughout all age groups. The model did not consider the potential effect of waning immunity. The results of this study suggest that measles elimination in the United States has been achieved by an effective immunization program aimed at young susceptibles combined with a highly, naturally immunized adult population. However, despite short-term success in eliminating the disease, long-range projections demonstrate that the proportion of susceptibles in the year 2050 may be greater than in the prevaccine era. Present vaccine technology and public health policy must be altered to deal with this eventuality.

Adolescent↗
PubMed1984

Mixture distributions in psychiatric research.

This paper describes the application of Gaussian mixture distributions to biological marker research in psychiatry. Mixtures of univariate and multivariate normal distributions can be used to determine if diagnostically similar psychiatric patients belong to biologically distinct subpopulations. The resulting biological subtypes may be important in understanding the etiology of psychiatric disorders. The general model and estimation procedure are described (EM algorithm; Dempster, Laird and Rubin 1977). The method is illustrated using two examples of biological data: (1) red cell membranes and monoamine oxidase activity data in normal individuals having no family history of psychiatric illness, the first-degree relatives of bipolar depressed patients and a heterogeneous patient population; and (2) smooth pursuit eye movements that classify relatives of schizophrenics, nonschizophrenics and normal controls into biologically distinct populations.

Bipolar Disorder↗
PubMed1983

Effects of phencyclidine, secobarbital and diazepam on eye tracking in rhesus monkeys.

Rhesus monkeys were trained to track a moving disk using a procedure in which responses on a lever were reinforced with water delivery only when the disk, oscillating in a horizontal plane on a screen at a frequency of 0.4 Hz in a visual angle of 20 degrees, dimmed for a brief period. Pursuit eye movements were recorded by electrooculography (EOG). IM phencyclidine, secobarbital, and diazepam injections decreased the number of reinforced lever presses in a dose-related manner. Both secobarbital and diazepam produced episodic jerky-pursuit eye movements, while phencyclidine had no consistent effects on eye movements. Lever pressing was disrupted at doses which had little effect on the quality of smooth-pursuit eye movements in some monkeys. This separation was particularly pronounced with diazepam. The similarities of the drug effects on smooth-pursuit eye movements between the present study and human studies indicate that the present method using rhesus monkeys may be useful for predicting drug effects on eye tracking and oculomotor function in humans.

Animals↗
PubMed1983

Relatives of unipolar and bipolar patients have normal pursuit.

Impaired smooth pursuit eye movements are significantly less prevalent among the first-degree relatives of patients who have major affective disorders than among the first-degree relatives of schizophrenics. The distribution of normal and abnormal smooth pursuit among the relatives of unipolar and bipolar patients does not differ from that of normal individuals having no family history of major psychosis. Smooth pursuit impairment is thus specific to relatives of schizophrenic patients and is not characteristic of relatives of patients with major affective disorders.

Adult↗
PubMed1983

Eye movement dysfunctions in psychiatric patients: a review.

Impairments of smooth pursuit eye movements occur in a high proportion of schizophrenic patients and in a lower but significant percentage of patients with affective psychoses, as well as patients with structural and metabolic disorders of the central nervous system. These findings have been confirmed using a wide range of tracking tasks, recording techniques, and scoring procedures, and therefore cannot be attributed to measurement artifact. The eye movement disruption in schizophrenics does not seem to result from drug treatment or simple inattention. Eye tracking pattern appears to be under genetic control and some impairments may reflect a predisposition to functional psychosis. The smooth pursuit eye movement impairment has been attributed to a central nervous system dysfunction that manifests itself in a disorder of nonvoluntary attention. The study of other oculomotor functions, such as the oculocephalic reflex, optokinetic and vestibular nystagmus, and saccadic eye movements, suggests that the locus of the central nervous system disruption is above the brainstem.

Adult↗
PubMed1983

Vestibular dysfunction and psychopathology.

A review of the empirical findings linking vestibular response abnormalities to psychopathology, and particularly to schizophrenia, indicates that these data do not unequivocally document the presence of peripheral or central disease of the vestibular system in any patient group. The reasons for this ambiguity include: use of imprecise stimulation techniques, inaccurate measures of responsiveness, unreliable measures of quantification, and the absence of experimental control over extravestibular variables. Future directions for research in this area are discussed, including the localizing information derived from properly conducted tests of the vestibulo-ocular reflex in studies of oculomotor function.

Adult↗
PubMed1982

Serum complement activity in pre-term pregnancies: relationship to duration of ruptured membranes and clinical infection.

Physiologic changes occurring during the latent period of prematurely ruptured membranes (PRM) are poorly understood. Indicators predicting maternal and neonatal infectious morbidity do not correlate well with clinical outcomes. A previous report suggested that in vivo complement consumption occurred in response to the event of membrane rupture. In this prospective study, complement activity was measured serially throughout the latent period in cases of preterm PRM. In addition to total hemolytic complement activity (CH50), C4-pro-activator (C3PA), a primary component of the alternate complement pathway, was measured in maternal and cord sera. As with CH50, cord serum C3PA levels are significantly less than those in matched maternal samples. Neither maternal nor cord serum complement activity correlated with either the duration of the latent period or maternal-neonatal infection.

Bacterial Infections↗