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Biomedical subjects

E R Berman

Publications and source records attributed to E R Berman.

At least 19 recordsLinked to original sources
PubMed1993

Hydroxyl radical generation in the cat retina during reperfusion following ischemia.

There is increasing evidence that oxygen-derived free radicals are generated during the early phase of reperfusion, and account for part of the damage caused by transient ischemia in various tissues. To study this in the retina, cats were injected intravenously with sodium salicylate (100 mg kg-1), which reacts as a hydroxyl radical trap to form 2,3- and 2,5-dihydroxybenzoic acids (DHBA). Thirty minutes following injection, the retina of one eye of each animal was subjected to ischemia by intraocular pressure elevation via cannulation of the anterior chamber, while the fellow eye served as a sham-operated control. Ischemia was induced for 60 min (six eyes) and 90 min (eight eyes) followed by 5 min of reperfusion. In six other eyes, ischemia was induced for 90 min without reperfusion. After enucleation, the retinas were immediately removed, placed in ice-cold buffer and the retinal levels of 2,3- and 2,5-DHBA were quantitated by high pressure liquid chromatography, coupled with electrochemical detection. Results were normalized and expressed as ng DHBA microgram-1 salicylate mg-1 retinal protein. After 60 min of ischemia followed by reperfusion the normalized levels of 2,3- and 2-5-DHBA were no different in the experimental and control retinas. However, the levels of both 2,3- and 2,5-DHBA were significantly higher in the retinas subjected to 90 min ischemia followed by reperfusion than in the control tissues (P = 0.012 and P = 0.036, n = 8 respectively). Following 90 min ischemia without reperfusion, the normalized dihydroxybenzoate levels in the retinas were no higher than in their controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The effect of psychiatric disorders on weight loss in obesity clinic patients.

Research on psychiatric disorders in obesity has indicated that obese people are not psychiatrically different from nonobese people. Few studies, however, have addressed the potential impact of psychopathology on weight control. In the present study, a consecutive sample of 37 patients presenting to a major metropolitan weight control unit were given structured diagnostic interviews (Structured Clinical Interviews for Diagnosis I and II). These patients completed one of two 12-week diet programs involving either behavior modification or liquid protein diets. After 12 weeks of a liquid protein formula diet, patients with no personality disorder lost significantly more weight than personality disordered patients; personality disordered patients on a behavioral diet tended (p < .15) to lose more weight during a 12-week diet than the patients without personality disorders. These data suggest that there are differential responses to liquid protein and behavioral diets, depending on the presence or absence of a personality disorder.

Adult↗
PubMed1992

Discrepancy between self-reported and actual caloric intake and exercise in obese subjects.

BACKGROUND AND METHODS: Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet--low total energy expenditure and underreporting of caloric intake--in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance. RESULTS: Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (+/- SD) of 47 +/- 16 percent and overreported their physical activity by 51 +/- 75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P < 0.05 as compared with group 2). CONCLUSIONS: The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis.

Calorimetry↗
PubMed1991

Oxygen saturation by pulse oximetry in healthy infants at an altitude of 1610 m (5280 ft). What is normal?

Pulse oximetry is a valuable, noninvasive technique for assessing oxygen saturation that has gained wide clinical acceptance despite little available information concerning normal values in the newborn, especially at an altitude different than sea level. We performed serial pulse oximetry studies on 150 term, appropriate-weight-for-gestational-age, clinically healthy infants at an altitude of 1610 m (5280 ft) at 24 to 48 hours, 1 month, and 3 months of age to define a reference range for oxygen saturation as a guideline in clinical care. We found that mean oxygen saturation at 24 to 48 hours of age is 92% to 93% and varies little with infant activity. With increasing postnatal age, there is a tendency for increased oxygen saturation during the awake states to 93% to 94%, while oxygen saturation during sleep stays the same or even decreases slightly. The lower end of the reference range (2 SDs below the mean) is as low as 85% during feeding at 24 to 48 hours of age, and as low as 86% during quiet sleep at 1 and 3 months of age, with 88% to 89% the lower limit in other activities at all ages.

Age Factors↗
PubMed1990

Prediction of the need for transfusion during anemia of prematurity.

We reviewed erythrocyte transfusions, given after 2 weeks of age to premature infants, to derive patient selection criteria for trials of administration of recombinant human erythropoietin to maintain hematocrit during the anemia of prematurity. We first studied 122 infants, less than 36 weeks of gestational age, who remained in a level 3 nursery longer than 4 weeks. Multiple logistic regression analysis was used to select those variables associated with more than two transfusions after the second week; these included gestational age, 5-minute Apgar score, transfusion during the first week, and patent ductus ligation. The best predictor, alone or combined, was gestational age less than 30 weeks. This predictor was applied to a second population of 44 premature infants from a level 2 nursery, and we found a 94% probability of excluding those infants who did not receive a transfusion. This information will allow selection of premature infants who are candidates for administration of recombinant human erythropoietin.

Anemia↗
PubMed1990

Lipids in human lipofuscin-enriched subcellular fractions of two age populations. Comparison with rod outer segments and neural retina.

The fatty acid composition and content of total phospholipids, free fatty acids (FFA), diacylglycerols (DG), phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE) were studied in lipofuscin granules of human donors in two age groups, young (less than 40 yr old) and old (more than 47 yr old), and compared with lipids of the photoreceptor rod outer segments (ROS). Neural retina (NR) and retinal pigment epithelium (RPE) also were studied. In both age groups, the lipid composition of the lipofuscin granules differed from that of the ROS, with a decrease in the proportion of phospholipid and an increase in FFA, suggesting very high phospholipase activity in the lipofuscin granules. In ROS, docosahexaenoic acid (22:6) was the predominant FFA, whereas palmitic acid (16:0), arachidonic acid (20:4) and oleic acid (18:1) were the major fatty acids in the lipofuscin granules. The fatty acid compositions of PC, PE, and PS of lipofuscin granules were different from those of the retina. There was proportionally less 22:6 in lipofuscin, and the amounts of saturated and monounsaturated fatty acyl chains such as 16:0, stearate (18:0), and 18:1 were greater than in retina. Compared to ROS, the lipofuscin granules showed a significant decrease in DG containing 20:4 but not 22:6. With aging, there was a decrease in the amount of total polyunsaturated fatty acyl chains (22:6 and 20:4) in the lipofuscin granules. These results show that the lipid composition of lipofuscin is different from that of ingested ROS, probably because of increased phospholipase and peroxidative activities in lipofuscin, directed toward ingested ROS as well as toward other materials from the RPE and blood.

Adolescent↗
PubMed1988

The fate of immunoreactive opsin following phagocytosis by pigment epithelium in human and monkey retinas.

Polyclonal and monoclonal antibodies to human rhodopsin were used to identify and localize this principal glycoprotein of the photoreceptor outer segment discs on thin sections of human and monkey retinal pigment epithelium (RPE) and on immunoblots of RPE subcellular fractions following gel electrophoresis. Antiopsin was visualized with protein A-gold labeling by electron microscopy or peroxidase-linked second antibody on immunoblots. In immunocytochemical studies using polyclonal antibodies, the rod outer segments (ROS) were heavily labeled whereas cone outer segments labeling was variable and more sparse. Phagosomes and other small bodies in the RPE, interpreted as secondary lysosomes, were labeled. In contrast, lipofuscin granules, osmiophilic residual bodies of the lysosomal system of the RPE, were negative. No reactive sites were found in Bruch's membrane or in drusen. A monoclonal antibody (MAB) specific for the amino terminus of human opsin and another MAB specific for the carboxy terminal region of bovine opsin produced labeling patterns similar to, but about one-half the density obtained with polyclonal antibodies. In the immunoblot analyses, the lipofuscin granule fraction from a sucrose density gradient of human RPE homogenates was positive for rhodopsin only in those specimens that were found, upon ultrastructural examination, to contain recognizable phagosomes. When phagosomes were lacking and therefore did not contaminate the lipofuscin granule fraction, the immunoblots were negative for opsin. Melanolipofuscin granule fractions were uniformly negative for opsin. We conclude that the superficial hydrophilic antigen binding sites on the opsin molecule for which the antibodies are specific have been altered or destroyed by lysosomal enzyme digestion within the phagolysosomal system of the RPE prior to formation of definitive lipofuscin granules. Thus, these antibodies are of limited value in revealing the ultimate fate of the whole rhodopsin molecule, eg, the hydrophobic sequences that are the most likely residues in lipofuscin granules.

Adult↗
PubMed1987

Vitamin E in human neural retina and retinal pigment epithelium: effect of age.

Vitamin E levels were measured in retina and retinal pigment epithelium from human eye bank donors of from 12-82 years of age. In comparison to an age group of 12-45 years, humans 59-82 years of age had a higher concentration of vitamin E in both retina and retinal pigment epithelium. Depending on age, the concentration of vitamin E in retinal pigment epithelium was from 4-7 times higher than in retina. Vitamin E accumulated in the human retinal pigment epithelium in an age dependent fashion, so that by 80 years it was from 3-4 times higher than in those 20 years old. The level of vitamin E in young human retinal epithelium, however, was higher than in comparable bovine tissue. The age-related increase in human tissue vitamin E levels does not appear to be affected by postmortem time.

Adult↗
PubMed1985

Retinyl ester hydrolase of bovine retina and pigment epithelium: comparisons to the rat liver enzyme.

The hydrolysis of 3H-retinyl ester was examined in the retinal pigment epithelium (RPE) and neural retina of cattle eyes and compared to that in homogenates of rat liver. The optimum pH for hydrolysis was 4.0-4.5 for RPE and 7.5-8.0 for liver. The RPE activity, which shows no variability between individual animals, is localized mainly in the lysosomal fraction of the cell. It is strongly inhibited by bile salts at concentrations as low as 0.2-0.5% and conversely, is strongly activated by Triton X-100, with maximum stimulation found at a concentration of approximately 1%. The apparent Vmax for hydrolysis of labeled retinyl ester in the RPE is 2.7 nmoles/hr/mg protein, a value approximately 1/150 to 1/200 of the rate of retinol esterification in these cells. Little or no hydrolytic activity could be detected in neural retina or in rod outer segments. Studies on the specificity of the RPE retinyl ester hydrolase activity revealed unexpectedly high hydrolytic activity toward both cholesteryl oleate and triolein, approximately 20 and 5 times greater, respectively, than in rat liver. The hydrolytic activity for cholesteryl oleate in the RPE was mainly at pH 3.5, while that for triolein showed three pH maxima, one at pH 4.5-5.0, a second near neutral pH and the third at pH 8. These findings reflect an active and complex pattern of fatty acyl ester lipid-metabolizing enzymes in cattle RPE whose interrelationships to one another require further clarification.

Animals↗
PubMed1980

Enzymatic esterification of vitamin A in the pigment epithelium of bovine retina.

The kinetic properties and subcellular distribution of an esterifying enzyme in the pigment epithelium of bovine retina have been studied using both [1-3H]retinol and [3H]retinol bound to cellular retinol-binding protein as substrates. The most active esterifying fraction in pigment epithelial cell preparations was the microsomes, but the lysosome plus mitochondria fraction also showed some activity, probably due to endoplasmic reticulum present as an impurity. The microsomal enzyme showed optimum activity at pH 7.5, and the reaction was linear up to 30 microgram protein and for the first 10-15 min. The apparent Km values were 16.6 . 10(-6) and 5.5 . 10(-6) M for [3H]retinol and bound [3H]retinol, respectively. This is the first time that retinol bound to cellular retinol-binding protein has been shown to undergo metabolic transformation. The microsomal esterifying activity was destroyed by boiling for 1 min, or after freezing for 2 months. No clear requirement for ATP, CoA or fatty acid could be demonstrated. Of all the other tissues examined under the same experimental conditions as those used for the pigment epithelium, only intestine showed measurable activity. With larger amounts of tissue protein and longer incubation periods, activity was also detectable in microsomes of liver, testis and retina.

Animals↗
PubMed1980

Lipofuscin of human retinal pigment epithelium.

Analysis of the fluorescent spectra of chloroform-methanol extracts of human retinal pigment epithelium confirmed the presence of lipofuscin pigments in the pigment epithelium of older individuals. Similar fractions in the pigment epithelium of young individuals were present in insufficient quantities for spectral analysis. Electron microscopy of the pigment epithelium of these eyes showed few or no lipofuscin granules in young eyes but large numbers in older eyes.

Adult↗