Search PubMed⌕ Search

Biomedical subjects

B Levin

Publications and source records attributed to B Levin.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

Chondrocalcinosis in elderly persons.

Fifty-eight elderly people were surveyed for chondrocalcinosis with knee, hip and pelvic roentgenograms using Type M industrial x-ray film. Chondrocalcinosis was found in 16 subjects (27.6%), an incidence greater than reported in previous studies. Roentgenograms of the knees alone showed the presence of chondrocalcinosis in 15 subjects. Varus deformity of the knees, increased wrist complaints and wrist involvement with clinical arthritis were significantly more common in subjects with chondrocalcinosis. Symptoms associated with acute inflammatory arthritis were not more common in people with chondrocalcinosis.

Aged↗
PubMedDate not supplied

The cusum test of homogeneity with an application in spontaneous abortion epidemiology.

We test the hypothesis of homogeneity over time in the rate of an event with a modification of Page's cumulative sum (cusum) procedure. The modification draws on an indifference zone approach to testing that is well suited to the epidemiologic study of retrospective data. We provide procedures for evaluating the significance level of the largest observed cusum value occurring in a sequence of fixed length. We draw inferences unconditionally with a known baseline rate of the event, and conditionally on observed margins with unknown baseline rate. Data collected over a five year period from one New York City hospital serve to illustrate the modified cusum test in a study of fluctuations in the proportions of chromosomally normal, trisomic, X-monosomic and triploid spontaneous abortions.

Abortion, Spontaneous↗
PubMedDate not supplied

Contrast sensitivity in dyslexia.

Contrast sensitivity was determined for dyslexic and normal readers. When testing with temporally ramped (i.e. stimuli with gradual temporal onsets and offsets) gratings of 0.6, 4.0, and 12.0 cycles/deg, we found no difference in contrast sensitivity between dyslexic readers and controls. Using 12.0 cycles/deg gratings with transient (i.e. abrupt) onsets and offsets, we found that dyslexic individuals had, compared to controls, markedly inferior contrast sensitivity at the shortest stimulus durations (i.e. 17, 34, and 102 ms). This deficit may reflect more sluggish temporal summation. There was no difference in sensitivity to 0.6 cycles/deg gratings with transient onsets and offsets. Under these conditions, the two groups showed a consistent and equal increase in sensitivity relative to the ramped baseline condition at 0.6 cycles/deg at the longer stimulus durations. This demonstrates that dyslexic readers have no deficit in their ability to detect stimulus transients, a finding which appears to be inconsistent with a transient system deficit. That detection of the low-frequency stimuli was mediated by the transient system is further indicated by the fact that these stimuli were more susceptible to forward masking than were the high-frequency stimuli. The effects of masking of both high and low spatial-frequency stimuli were about equal for dyslexic readers and controls. This is not in agreement with the transient system deficit theory, according to which one would expect there to be less masking of high spatial-frequency stimuli in the case of dyslexic readers.

Adolescent↗
PubMedDate not supplied

Effect of ionic and non-ionic contrast medium on aortic and pulmonary arterial pressure. An angiocardiographic study in rabbits.

Effects in angiocardiography from injections into the right atrium of rabbit hearts of a new, non-ionic contrast medium (Amipaque) were studied and were compared with the effects from injections of an ionic medium (Isopaque Coronar) at a dose of 3 ml/kg rabbit and concentration of 370 mg I/ml. Forty-seven experiments in 11 rabbits are reported. Amipaque produced a significantly (p less than 0.001) smaller increase in pulmonary arterial pressure (29%) than Isopaque Coronar (82%). Simultaneously (within 12 seconds from the beginning of an injection) Amipaque produced an increase in aortic pressure of 21%. About 10-15 seconds later when the contrast media had reached peripheral vessels Amipaque produced a significantly (p less than 0.001) smaller decrease of aortic pressure (12%) than the decrease produced by Isopaque Coronar (40%). The differences found between the two types of contrast media are believed to be related to, among other factors, their different osmolality. The osmolality of Amipaque was about one third of the osmolality of Isopaque Coronar.

Angiocardiography↗
PubMedDate not supplied

Life event questionnaires for measuring presumptive stress.

Cumulative stress from the impact of life events has become an important variable in psychosomatic and psychological research. This article provides both short and long life events questionnaires that add to incidence information the remoteness or recency in time of a given experience. In the weight assignment system that leads to a single presumptive stress score, events remote in time have less influence than recent events. The reliability of weight assignment was checked in subject groups that differed by sex, age, and status. Women weighted life events as more stressful than did men; other differences in groups were less important. In spite of the sex differential, review of these data suggests use of the same weight assignments for all subgroups rather than differential weighting by sex and age. Reliability was also checked by test and retest methods in contrast to common sense expectation, a disappointingly low level of reliability was found. The implications for investigative use of life events questionnaires are discussed.

Adult↗