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Biomedical subjects

F J Kelly

Publications and source records attributed to F J Kelly.

At least 127 records · Page 7Linked to original sources
PubMed1990

Time course of vitamin E repletion in the premature infant.

Plasma and erythrocyte (RBC) tocopherol-isomer concentrations were determined serially in forty-two premature infants (25-35 weeks gestation) from birth to 8 weeks of age. For comparison purposes vitamin E status was also determined in six term infants over the first 8 d following birth and in a group of thirteen adult volunteers. Vitamin E intakes in term and preterm infants were calculated from recorded food intakes and blood transfusions. In term infants plasma vitamin E concentration rose from 1.9 mg/l (day 1) to 8.2 mg/l by day 8. In comparison preterm plasma vitamin E concentration, 0.3 mg/l (day 1), did not change appreciably by day 8 (0.7 mg/l). Likewise RBC vitamin E concentration increased in term infants from 1.3 mg/l (day 1) to 2.7 mg/l (day 8), while in preterm infants it remained unchanged, 1.5 mg/1 (day 1) v. 1.3 mg/l (day 8). Over the 3 weeks following birth, RBC vitamin E concentrations in the premature infants increased to adult values, while plasma vitamin E concentration did not reach the adult range until 8 weeks post-term. These slow changes in plasma vitamin E status occurred even though the vitamin E intake of these infants was similar to that proving adequate for term infants.

Adult↗
PubMed1990

Developmental expression of antioxidant enzymes in guinea pig lung and liver.

Antioxidant enzyme activities, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total glutathione concentration were determined in guinea pig lung and liver over the final period of gestation (days 50-68) and at several ages post-partum. Pulmonary antioxidant capacity increased markedly over the final days of gestation, individual changes ranging from 29% (glutathione) to 198% (GSH-Px). Liver antioxidant capacity was always 4-fold to 10-fold greater than that of the lung and exhibited very similar developmental profiles to those observed in the lung. From day 60 gestation to term (68 days), activity of the liver antioxidants increased, ranging from 246% (CAT) to 610% (glutathione). A number of antioxidants in both lung and liver exhibited either immediate pre- or post-birth decreases in activity. These falls could not be attributed to the way in which the results were expressed: i.e. they were similar, expressed per unit DNA, per unit protein, or per g wet wt. Following birth, liver antioxidant capacity increased such that the highest enzyme activities or glutathione concentration were recorded at 66 days post-partum. In lung, only Mn-SOD and glutathione exhibited higher levels at 66 days postpartum than at birth. In combination, these results of pulmonary and hepatic antioxidant enzyme activity indicate that the lung is not unique in acquiring increased antioxidant protection in the final period of gestation. They also suggest that a tissue's antioxidant requirement is dictated more by metabolic rate (hence free radical production) than incident partial pressure of oxygen.

Animals↗
PubMed1989

Study of ideal-self discrepancy and observed social behaviors in a therapeutic community.

This descriptive study explored relations between ideal self-discrepancy (often referred to as self-esteem or self-concept) and behaviors observed in 27 residents of a therapeutic community for polydrug users. The Sliding Person Test (SPERT), an abstract, nonverbal measure of self-reported, ideal self-discrepancy was administered three times a week, for seven consecutive weeks to 27 subjects after regularly scheduled group meetings. Data were charted on graphs to reveal fluctuations of ideal self-discrepancy and incidences of observed, documented changes in behavior. Analysis suggests the instrument detects some changes in ideal self-discrepancy congruent with transitional behaviors. In more than half of the cases, fluctuation of 25% or more in discrepancy between ideal self-concept and at-the-moment self-concept was directly related to an observed change in behavior or residents' transition in the hierarchy of the program's structure. Implications for validity and reliability issues concerning measures of ideal-self-discrepancy are briefly discussed.

Humans↗
PubMed1988

Effect of hyperoxic exposure on protein synthesis in the rat.

Rates of protein synthesis were measured in vivo [corrected] in the lung and heart from fed rats exposed to hyperoxia (less than or equal to 95% O2) for either 6 or 24 h. Protein synthesis rates were depressed by 16-32% compared with normoxic controls in these tissues. The inhibition in both tissues was greatest after 24 h hyperoxic exposure. The decreased fractional rates of synthesis in both tissues were related to changes in ribosomal activity rather than capacity. The fall in synthesis rate per ribosome was greatest in both tissues when the exposure period was increased to 24 h. The possible mechanism(s) involved in hyperoxia-induced depression of protein synthesis are discussed.

Animals↗
PubMed1986

A morphological/biochemical study on the actions of corticosteroids on rat skeletal muscle.

Four corticosteroid hormones were administered (5 mg/kg/day) to rats over 6 to 10 days. Both biochemical and microscopic techniques were employed to determine the influence of these corticosteroids on the fine structure and growth of five striated muscles. Throughout, dexamethasone and triamcinalone were more potent than prednisone or cortisone in influencing muscle growth. The corticosteroids' action on the heart was anabolic, increasing its RNA and protein content. In contrast, the same corticosteroids were catabolic against fast-twitch muscles (e.g., extensor digitorum longus), inducing appreciable atrophy. However, slow-twitch muscles (e.g., soleus) were more resistant to these hormones, exhibiting an intermediate response between that of the heart and fast-twitch muscles. Only minor morphological changes were found in both fast and slow muscles 10 days after the corticosteroid treatments. The hormones' atrophic effects on skeletal muscle primarily arose from the corticosteroid's ability to inhibit protein synthesis, via decreases in the muscles' ribosomal capacities. Whole-body protein synthesis was also suppressed by these corticosteroids, but to a lesser extent than in the whole skeletal musculature.

Adrenal Cortex Hormones↗
PubMed1985

Control of peptide-chain initiation in rat skeletal muscle. Development of methods for preparation of native ribosomal subunits and analysis of the effect of insulin on formation of 40 S initiation complexes.

A method was developed for isolation of native ribosomal subunits from rat gastrocnemius muscle. Native 40 S subunits which were isolated by this method retained their associated nonribosomal proteins and consisted primarily of particles with equilibrium densities of 1.41 and 1.48 g/cm3. Based on the binding of radiolabeled Met-tRNAmeti, the 1.41 g/cm3 particle was identified as the 40 S initiation complex. Insulin deficiency in vivo resulting from either diabetes or fasting led to a 2-fold increase in 75 S monomers but had no effect on the numbers of native 40 and 60 S subunits or the relative distribution of the 1.41 and 1.48 g/cm3 particles. The rate of protein synthesis in perfused muscle preparations derived from insulin-deficient rats was reduced to about half the control value. Addition of insulin to the perfusate restored protein synthesis and 75 S monomers to control levels. The effect of insulin on protein synthesis was associated with a 1.5-fold increase in the amount of Met-tRNAmeti bound to the 1.41 g/cm3 particle. These findings identify formation of 40 S initiation complexes as a site of action of insulin on protein synthesis in skeletal muscle.

Animals↗
PubMed1985

Protein turnover and cathepsin B activity in several individual tissues of foetal and senescent rats.

The fractional rate of protein synthesis has been measured in vivo, and compared in the whole body and 12 major individual tissues of foetal and senescent rats. This synthetic rate was found to decrease in most tissues with increasing animal age. The rate of protein degradation was also determined and compared with cathepsin B activity within each tissue; both protein turnover and the endopeptidase activity decreased with ageing. Age-related changes in each tissue's contributions to the protein mass and synthetic rates of the whole animal are also summarized and related to developmental variations in physiological function.

Aging↗
PubMed1984

Age-related growth and protein turnover in the thymus of normal and glucocorticoid-treated rats.

Age-related changes in the growth, nucleic acid content and protein turnover of the thymus have been studied in normal male rats. A rapid and massive atrophy was found at each age 24 h after exposure to cortisone acetate or dexamethasone; the thymus of sexually mature rats being most severely affected. The steroids decreased (70-90%) total protein synthesis in the thymus more than whole body synthesis (15%), indicating a more pronounced action on the thymus compared with other body tissues. Initially protein breakdown increased in the steroid-treated thymus but at longer times this change was reversed.

Aging↗
PubMed1984

Protein turnover and growth in the whole body, liver and kidney of the rat from the foetus to senility.

Changes in the growth and protein turnover (measured in vivo) of the rat liver, kidney and whole body were studied between 16 days of life in utero and 105 weeks post partum. Tissue and whole-body growth were related to changes in both cellular hyperplasia (i.e. changes in DNA) and hypertrophy (protein/DNA values) and to the protein composition within the enlarging tissue mass. The suitability of using a single large dose of phenylalanine for measuring the rates of protein synthesis during both pre- and post-natal life was established. The declining growth rates in the whole animal and the two visceral tissues were then explained by developmental changes in the fractional rates of protein synthesis and breakdown, turnover rates being age-for-age higher in the liver than in the kidney, which in turn were higher than those measured in the whole animal. The declining fractional rates of synthesis in both tissues and the whole body with increasing age were related to changes in the tissues' ribosomal capacity and activity. The fall in the hepatic rate between 18 and 20 days of foetal life (from 134 to 98% per day) corresponded to a decrease in both the ribosomal capacity and the rate of synthesis per ribosome. No significant changes in any of these parameters were, however, found in the liver between weaning (3 weeks) and senility (105 weeks). In contrast, the fractional synthetic (and degradative) rates progressively declined in the kidney (from 95 to 24% per day) and whole body (from 70 to 11% per day) throughout both pre- and post-natal life, mainly as a consequence of a progressive decline in the ribosomal capacity, but with some fall in the ribosomal activity also during foetal life. The age-related contributions of these visceral tissues to the total amount of protein synthesized per day by the whole animal were determined. The renal contribution remained fairly constant at 1.6-2.9%, whereas the hepatic contribution declined from 56 to 11%, with increasing age. Approximate-steady-state conditions were reached at, and between, 44 and 105 weeks post partum, the half-life values of mixed whole-body, kidney and liver proteins being 6.4, 3.0 and 1.5 days, respectively, at 105 weeks.

Aging↗
PubMed1984

Pre- and post-natal growth and protein turnover in smooth muscle, heart and slow- and fast-twitch skeletal muscles of the rat.

The growth of one smooth and three individual striated muscles was studied from birth to old age (105 weeks), and where possible during the later stages of foetal life also. Developmental changes in protein turnover (measured in vivo) were related to the changing patterns of growth within each muscle, and the body as a whole. Developmental growth (i.e. protein accumulation) in all muscles involved an increasing proportion of protein per unit wet weight, as well as cellular hypertrophy. The contribution of the heart towards whole-body protein and nucleic acid contents progressively decreased from 18 days of gestation to senility. In contrast, post-natal changes in both slow-twitch (soleus) and fast-twitch (tibialis anterior) skeletal muscles remained reasonably constant with respect to whole-body values. Such age-related growth in all four muscle types was accompanied by a progressive decline in both the fractional rates of protein synthesis and breakdown, the changes in synthesis being more pronounced. Age for age, the fractional rates of synthesis were highest in the oesophageal smooth muscle, similar in both cardiac and the slow-twitch muscles, and lowest in the fast-twitch tibialis muscle. Despite these differences, the developmental fall in synthetic rates was remarkably similar in all four muscles, e.g. the rates at 105 weeks were 30-35% of their values at weaning. Such developmental changes in synthesis were largely related to diminishing ribosomal capacities within each muscle. When measured under near-steady-state conditions (i.e. 105 weeks of age), the half-lives of mixed muscle proteins were 5.1, 10.4, 12.1 and 18.3 days for the smooth, cardiac, soleus and tibialis muscles respectively. Old-age atrophy was evident in the senile animals, this being more marked in each of the four muscle types than in the animal as a whole. In each muscle of the senile rats the protein content and composition per unit wet weight, and both the fractional and total rates of synthesis, were significantly lower than in the muscles of younger, mature, animals (i.e. 44 weeks). In the soleus the decreased synthesis rate appeared to be related to a further fall in the ribosomal capacity. In contrast, the changes in synthesis in the three remaining muscles correlated with significant decreases in the synthetic rate per ribosome.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1984

Protein synthesis during the developmental growth of the small and large intestine of the rat.

The developmental growth and associated changes in protein synthesis were measured (in vivo) in the combined small and large intestine from 18 days in utero to 105 weeks post partum. Similar post-natal (3-105 weeks) changes were also studied in the separated large and small intestine, and in the mucosal and muscularis externa + serosal layers of the small intestine. Although the protein and nucleic acid contents of the whole intestine increased throughout both pre- and post-natal life, the maximal (11%) intestinal contribution to whole-body growth occurred 3 weeks after birth; this value declined to only 2.5-3.5% at both extremes of the age range studied. Between the 18-day foetus and old age the fractional rate of protein synthesis decreased from 107 to 61% per day. This developmental decline (43%) was, however, much smaller than that found in most other body tissues over the same period. Similar developmental trends (between weaning and senility) were found in both the small and the large intestine when studied separately, the small intestine in all respects contributing proportionately more than the large intestine to both the combined intestinal and whole-body values. At each age the large intestine possessed significantly lower fractional rates of synthesis and associated ribosomal activities. For the most part, the fractional synthesis rates in the mucosa and serosa of the small intestine were very similar, with each declining slightly with increasing age. These developmental changes are discussed with respect to functional aspects within the gastrointestinal tract.

Aging↗
PubMed1983

Age-related growth of the spleen in normal and glucocorticoid treated rats.

1. Age-related changes in the growth, nucleic acid content and protein turnover of the spleen have been studied in normal male rats. 2. A rapid and marked atrophy of the spleen, was found 24 hr after exposure to cortisone or dexamethasone; increased rates of protein breakdown being primarily responsible. 3. Nonetheless, the total amount of protein synthesized in the spleen (measured in vivo) was significantly decreased (30-50%) 24 hr after exposure to these steroids. 4. This compared with only a 15% decrease in whole body protein synthesis, indicating a more pronounced hormonal effect on the spleen than on most other body tissues.

Age Factors↗
PubMed1982

The differing responses of four muscle types to dexamethasone treatment in the rat.

The glucocorticoid dexamethasone dramatically altered growth patterns in four muscle types, inducing atrophy of smooth and fast-twitch skeletal muscle, suppressing protein accumulation in slow-twitch muscle and enhancing growth in the heart. These differing responses were explained by steroid-induced changes in RNA content, protein synthesis and protein breakdown.

Animals↗
PubMed1982

Exercise-induced morphological and biochemical changes in skeletal muscles of the rat.

Morphological and biochemical changes have been studied in two forelimb (i.e., brachialis and extensor carpi radialis) and two hindlimb (i.e., soleus and extensor digitorum longus) muscles of rats subjected to short bursts of high-intensity exercise over 2 wk. Regardless of muscle type, all four muscles grew significantly, accumulating protein, RNA, and DNA at faster rates than in the growing control tissues. Of the intrinsic fiber types within the individual muscles all increased their cross-sectional areas, but the fast-oxidative, glycolytic fibers (type IIa) showed marginally more hypertrophy than the slow-oxidative (I) or fast-glycolytic fibers (IIb). Induced changes in protein turnover were consistent with the additional growth of the exercised muscles. However, the precise alterations in the rates of protein synthesis and protein breakdown varied according to the fiber type composition of the muscle. The increased growth rate of the two principally fast-twitch muscles (i.e., brachialis and extensor digitorum longus) correlated solely with an enhancement of protein synthesis (measured in vivo). In contrast, the hypertrophy of the slow-twitch soleus appeared to relate only to a decrease in protein breakdown (a calculated value). In a more intermediate type of muscle (i.e., extensor carpi radialis) a complementary combination of an increase in synthesis and a decrease in breakdown was found.

Animals↗