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Biomedical subjects

S Lieberman

Publications and source records attributed to S Lieberman.

At least 19 recordsLinked to original sources
PubMed1996

Association of macronutrients and energy intake with hypertension.

Hypertension, a major public health problem, becomes more prevalent during aging. Epidemiological studies suggest that environmental factors such as nutrition may play a major role in blood pressure (BP) regulation. It is generally accepted that obesity and sodium/alcohol consumption are important factors, and many believe that calcium, magnesium and potassium consumption are regulatory as well. Less emphasis has been placed on whether macronutrients influence blood pressure significantly. This review focused on the ability of excess calories and consumption of carbohydrates, fats, and proteins to regulate blood pressure.

Dietary Carbohydrates↗
PubMed1995

Effects of chromium and guar on sugar-induced hypertension in rats.

Ingestion of sugars (sucrose, fructose, glucose) by various rat strains is associated with perturbations in the glucose/insulin system and higher systolic blood pressure (SBP). The association suggests causality, because alterations in insulin metabolism have been found in essential hypertension and many experimental forms of hypertension. To test the hypothesis that sugar-induced SBP elevation is secondary to perturbed insulin metabolism, we examined in 2 experiments effects of chromium and guar, substances known to affect insulin metabolism, on SBP of Spontaneously Hypertensive Rats (SHR). In both studies, sucrose compared to starch ingestion caused significant elevation of SBP; but addition of 2 chromium nicotinate complexes and guar prevented development of sugar-induced SBP elevations. The basal, genetic hypertension of the SHR was not affected by either nutrient. An additional finding in the first study was that sugar-consuming SHR supplemented with chromium had greater BW and increased organ weight (kidney, spleen, and liver) than nonsupplemented SHR. Accordingly, we have shown that two different mechanisms known to ameliorate insulin perturbations, use of chromium and guar, prevent sugar-induced SBP elevations. Since essential hypertension may be due to insulin perturbations and high dose chromium supplementation seems nontoxic, this may prove to be a useful means to lower blood pressure (BP) in some essential hypertensives, as well as diabetic hypertensives. Soluble fiber in the form of guar is also quite effective in favorably influencing sugar-induced SBP elevations.

Animals↗
PubMed1994

Precursors of the neurosteroids.

In addition to the neurosteroids pregnenolone and dehydroepiandrosterone, organic solvent extracts of rat brains contain related compounds that react with various reagents to yield additional amounts of these ketosteroids. Among the chemicals producing these increments are triethylamine, HCl, FeCl3, and Pb(OAc)4. Most revealing is the action of FeSO4 on these extracts. This reducing agent also converts components of the extract into the two neurosteroids, suggesting the presence of sterol hydroperoxides or peroxides in brain. The clues provided by this study indicate that the chemical nature of the steroidal constituents existing in extracts of mammalian brains remains to be determined. It is likely that their association with neurological functions will be better understood when the structures of these substances are established.

Animals↗
PubMed1993

Steroids and their conjugates in the mammalian brain.

Five steroids--3 beta-hydroxypregn-5-en-20-one (pregnenolone; P), 3 beta-hydroxy-5 alpha-pregnan-20-one (3 beta-AP), 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-AP), 3 beta-hydroxyandrost-5-en-17-one (dehydroepiandrosterone; D), and 3 beta-hydroxy-5 alpha-androstan-17-one (EpiA)--were extracted from the brains of adult male rats, rabbits, and dogs. The steroids exist in this organ as unconjugated compounds and as sulfates, lipoidal esters, and sulfolipids. The techniques for separating these four classes of steroids from each other and for separating the five steroids from each other are described. In all cases, the steroids were identified by their retention time (Rt) on HPLC, their Rt by gas chromatography, and by selected ion monitoring of their mass spectra. The latter were also used for quantification. In their reaction toward organic bases, the sulfolipid conjugates resemble previously described sulfolipids of cholesterol and sitosterol. These conjugates are relatively abundant in brain, particularly those of P and D, and this suggests that, in the search for the physiological significance of these brain constituents, these conjugates warrant attention.

Animals↗
PubMed1993

The octamer/mu E4 region of the immunoglobulin heavy-chain enhancer mediates gene repression in myeloma x T-lymphoma hybrids.

We have shown previously that the immunoglobulin heavy-chain enhancer acts as a repressor of gene transcription in hybrids between immunoglobulin-producing myelomas and a T-lymphoma line. We have now mapped this repressive activity to a 51-bp enhancer subfragment which contains the octamer and mu E4 protein-binding motifs. Even a single copy of this subfragment will repress gene expression in hybrid cells. Mutational analyses of the repressor fragment suggest that in non-B cells, a strong transcriptional repressor(s) functions through the same motifs important for gene activation in B cells. Changes in chromatin structure that accompany reporter gene repression suggest a general mechanism for prohibiting immunoglobulin heavy-chain locus activation in inappropriate cell types.

Animals↗
PubMed1992

Steroidogenic potential of lyophilized mitochondria from bovine adrenocortical tissue.

When incubated with [3H]cholesterol, a bovine adrenocortical mitochondrial pellet obtained by centrifugation at 12,000 x g yielded, as expected, only the C21O2 metabolites progesterone and pregnenolone. However, the steroidogenic potential of the 12,000 x g pellet fraction was augmented significantly by lyophilization. After lyophilization, the 12,000 x g pellet converted the sterol into C19 androgens and corticosteroids, in addition to C21O2 pregnane derivatives. Leaching the lyophilized mitochondrial fraction with either hexane or acetone increased substantially the yields of the metabolites. It did not change qualitatively the array of metabolites formed during in vitro incubation, but 5 alpha-reductase activity was unmasked by the washings, particularly with acetone. Thus, the fraction sedimented at 12,000 x g contains the complete complement of steroidogenic enzymes required for the biosynthesis of the aforementioned adrenal hormones. These results cast doubt upon the widely held belief that the various enzymes required for adrenocortical steroidogenesis are distributed between two different subcellular compartments, the mitochondrion and the endoplasmic reticulum.

Adrenal Cortex↗
PubMed1992

Family therapy.

The discipline of family therapy, one of the psychotherapies, is defined and illustrated clinically in this article using case material. References are provided which allow further reading about family systems medicine.

Aged↗
PubMed1990

Troubled parents: vulnerability and stress in childhood cancer.

The psychosocial stresses of having a child with cancer were examined in a group of 18 parents using standard psychiatric measurement scales and a lengthy semi-structured interview. Findings confirmed that staff/parent communication is difficult in a large institution but can be facilitated by staff who are aware of the difficulty. Two kinds of psychopathology were demonstrated in the parents. Thirteen of the 18 suffered symptoms of anxiety outside the normal range: of these 13, six had moderate or severe symptoms which warranted further attention. A group of six parents showed marked communication difficulty with staff, friends and their own spouses. The latter may represent a pre-existing personality trait but one which makes the experience of having a child with cancer even more distressing.

Adaptation, Psychological↗
PubMed1989

Studying the 'Grammar of Psychotherapy' Course using a student and control population. Some results, trends and disappointments.

In a study of the effects of the teaching of the 'Grammar of Psychotherapy' Course, 26 subjects were matched with 27 controls. The students were found to have significantly better interviews than the controls as rated by their patients and by independent blind assessment of their audiotapes six months later. There are some trends which were of interest, although not statistically significant.

Adult↗
PubMed1989

Effects of ocular functioning and time upon reading proficiency.

We hypothesize that children with fusional and/or accommodative abnormalities will tend to tire more readily when reading than will children with normal vision and that, consequently, they will show a greater decrement in reading proficiency over time on a task requiring reading. Forty-five subjects who passed the New York State Optometric Association Vision Screening Battery and 32 who failed were given a "maze" reading test developed for the study. The abnormal vision group made significantly more errors than did the normal vision group on the reading test. The abnormal vision group also made progressively more errors than did the normal vision group at the end of each segment of the reading test. The differences, however, were not statistically significant. While the correlations between speed and accuracy reversed over time, the abnormal vision group began and ended at the most extreme levels, having undergone a significantly more radical shift in this regard.

Accommodation, Ocular↗