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Biomedical subjects

M Gersten

Publications and source records attributed to M Gersten.

8 recordsLinked to original sources
PubMed1990

Psychiatric correlates of behavioral inhibition in young children of parents with and without psychiatric disorders.

Behavioral inhibition is a laboratory-based temperamental category by the tendency to constrict behavior in unfamiliar situations and assumed to reflect low thresholds of limbic arousal. We previously found behavioral inhibition prevalent in the offspring of parents with panic disorder and agoraphobia. In this report, we examined the psychiatric correlates of behavioral inhibition by evaluating the sample of offspring of parents with panic disorder and agoraphobia, previously dichotomized as inhibited and not inhibited, and an existing epidemiologically derived sample of children, followed by Kagan and colleagues and originally identified at 21 months of age as inhibited or uninhibited. A third group of healthy children was added for comparison. Our findings indicate that inhibited children had increased risk for multiple anxiety, overanxious, and phobic disorders. It is suggested that behavioral inhibition may be associated with risk for anxiety disorders in children.

Agoraphobia↗
PubMed1990

3-D corneal modeling system.

New surgical procedures have been introduced recently that provide refractive correction to replace the use of eyeglasses or contact lenses. The procedures involve reshaping the cornea to compensate for the optical anomalies of astigmatism and nearsightedness. Although thousands of operations are currently performed in the U.S., there are no instruments available for monitoring the results. Thus, a critical need has arisen to inspect and measure the cornea's surface both before and after surgery. In this paper an instrument is presented which provides a detailed topographical model of an individual's cornea. The method uses a novel structured light source. The cornea is modeled as a convex mirror which forms a virtual image of the structured light source. A single image is recorded from the patient's cornea. The depth is obtained from triangulation between the acquired image and a reference image of a sphere. The reconstruction of the depth map is complicated by the fact that the magnification used in recording the image varies with the radius of curvature of the cornea. An iterative method is presented which solves for the radius of curvature despite the variation in magnification. The virtual image is digitized and the instantaneous curvature of the cornea is obtained. The instantaneous curvature is displayed in units of optical power (diopters). This display provides the ophthalmologist or optometrist with the essential optical properties of the cornea.

Cornea↗
PubMed1988

Behavioral inhibition in children of parents with panic disorder and agoraphobia. A controlled study.

To investigate the role of "behavioral inhibition to the unfamiliar" as an early temperamental characteristic of children at risk for adult panic disorder and agoraphobia (PDAG), we compared children of parents with PDAG with those from psychiatric comparison groups. Fifty-six children aged 2 to 7 years, matched for age, socioeconomic status, ethnic background, and ordinal position, were blindly evaluated at the Harvard Infant Study laboratory, Cambridge, Mass. The rates of behavioral inhibition in children of probands with PDAG, with or without comorbid major depressive disorder (MDD), were significantly higher than for our comparison group without PDAG. Further, the data suggest a progression of increasing rates of inhibition from the comparison group without MDD (15.4%), to MDD (50.0%), and to comorbid PDAG and MDD (70%) and PDAG (84.6%). In contrast, the rate of behavioral inhibition in children of probands with MDD did not meaningfully differ from the comparison group without MDD. Behavioral inhibition to the unfamiliar, as defined and measured in the previous work of the Harvard Infant Study program, is highly prevalent in the offspring of adults in treatment for PDAG. These children appear to be at risk for distress and disability in childhood and also perhaps for development of psychiatric disorder in later childhood and aulthood.

Adolescent↗
PubMed1988

Corneal modeling.

The Corneal Modeling System is presented as an integrated instrument system designed to give the corneal surgeon the capability of measuring and designing alterations of corneal shape that are comparable to the computer-aided design (CAD) capability used in aerospace design and other industries. The system provides realtime digital video image acquisition using a high-resolution, cylindrical photokeratoscope and scanning laser slit lamp. From these digitized images, the system's computer derives topographic and pachymetric information in sufficient density to produce a continuous mathematical function that represents both the front and the back surface of the cornea. The mathematical model may then be sampled in as many points as the clinical application requires, in the form of either computer graphics or a numerical data stream to control precision machinery to make contact lenses or tissue lenses. Representative computer graphics of normal and pathologic corneal conditions are presented.

Cornea↗
PubMed1986

The effect of verapamil on pancreatic exocrine secretion.

This study set out to examine the effects of a Ca++ channel blocker, verapamil, on pancreatic exocrine secretion because of the known relationship between amylase secretion and intracellular Ca++. Pancreatic secretion was stimulated in dogs by infusing secretin and cholecystokinin. Verapamil was found to inhibit the secretion of amylase but to have no effect on lipase, trypsin, or total protein. There was no effect on the secretion of water and bicarbonate. To determine the possible physiologic significance of these findings, the pancreas was stimulated by a meat meal, and verapamil was found to inhibit amylase secretion again and in addition to inhibit the secretion of water and bicarbonate. The results suggest that verapamil has an inhibitory effect on amylase secretion by blocking the influx of Ca++ into the acinar cell and has an indirect effect leading to inhibition of water and bicarbonate secretion from the duct cells.

Amylases↗
PubMed1976

Separation of two hepatitis B human antibody fractions by cold-ethanol precipitation.

Antibodies to three different samples of hepatitis B antigen-positive serum were found to be absent from a Cohn fraction II hepatitis B immune globulin preparation, but present in the whole plasma from which the immune globulin was made. Fractions containing the antibodies specific for the three antigen samples were isolated from the plasma by euglobulin precipitation, and the antibodies were characterized as to immunoglobulin class and precipitability in the Cohn fractionation procedure. They appear to be IgG antibodies which, however, were detectable only in Cohn fraction I, while the remainder of the HB specificity present in the original plasma was found, as expected, in fraction II.

Antibodies↗