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Biomedical subjects

P Dexter

Publications and source records attributed to P Dexter.

6 recordsLinked to original sources
PubMed1994

Distribution and predictors of depressive symptoms in osteoarthritis.

OBJECTIVE: To determine the prevalence and correlates of depressive symptoms in a sample of elderly persons with osteoarthritis (OA). METHODS: Secondary analysis of cross sectional interview data from 108 community living persons age 50 or over who met American College of Rheumatology clinical criteria for OA of the hip and/or knee. RESULTS: The prevalence of substantial depressive symptomatology appeared to be no greater than would be expected in the general population for this age group. However, persons currently under a physician's care for OA were significantly more depressed than those not under care, and, with the exception of those who had post-high school education, depression was a better predictor of being under care than OA symptoms. The direct and interactive effects of 3 variables--education, age and self-perceived impact of the OA problem--were found to explain 40% of variance in depression scores in the total sample and 50% among those currently receiving care. Younger and less educated subjects had relatively more depressive symptoms and, furthermore, in this subgroup the correlation between OA impact and depression was high. CONCLUSIONS: The importance of assessing depression in persons who seek care for OA is supported. Furthermore, our results suggest that the observed relationship between education and arthritis outcomes could be mediated, at least in part, by depression.

Age Factors↗
PubMed1993

Relationships between social background and medical care in osteoarthritis.

Arthritis is relatively more prevalent among those of low socioeconomic status and it is important that this group have access to good arthritis care. In our study looking at relationships between socioeconomic status and medical care, histories were obtained from a convenience sample of 110 community living elderly persons of varying social backgrounds who had symptomatic osteoarthritis (OA) of the hip and/or knee. Almost all subjects had seen a physician at some time for their OA, and low income and black subjects were twice as likely to be currently receiving OA care as others. However, in looking at instruction and monitoring in relation to therapeutic joint exercises as a qualitative aspect of medical care, subjects who had both above mean OA impairment and more than a high school education were found to have received much more comprehensive care than any other subgroup.

Aged↗
PubMed1990

Regulation of the branched-chain alpha-ketoacid dehydrogenase and elucidation of a molecular basis for maple syrup urine disease.

The hepatic branched-chain alpha-ketoacid dehydrogenase complex plays an important role in regulating branched-chain amino acid levels. These compounds are essential for protein synthesis but toxic if present in excess. When dietary protein is deficient, the hepatic enzyme is converted to the inactive, phosphorylated state to conserve branched-chain amino acids for protein synthesis. When dietary protein is excessive, the enzyme is in the active, dephosphorylated state to commit the excess branched-chain amino acids to degradation. Inhibition of protein synthesis by cycloheximide, even when the animal is starving for dietary protein, results in activation of the hepatic branched-chain alpha-ketoacid dehydrogenase complex to prevent accumulation of branched-chain amino acids. Likewise, the increase in branched-chain amino acids caused by body wasting during starvation and uncontrolled diabetes is blunted by activation of the hepatic branched-chain alpha-ketoacid dehydrogenase complex. The activity state of the complex is regulated in the short term by the concentration of branched-chain alpha-ketoacids (inhibitors of branched-chain alpha-ketoacid dehydrogenase kinase) and in the long term by alteration in total branched-chain alpha-ketoacid dehydrogenase kinase activity. cDNAs have been cloned and the primary structure of the mature proteins deduced for the E1 alpha subunit of the human and rat liver branched-chain alpha-ketoacid dehydrogenase complex. The cDNA and protein sequences are highly conserved for the two species. Considerable sequence similarity is also apparent between the E1 alpha subunits of the human branched-chain alpha-ketoacid dehydrogenase complex and the pyruvate dehydrogenase complex. Maple syrup urine disease is caused by an inherited deficiency in the branched-chain alpha-ketoacid dehydrogenase complex. The molecular basis of one maple syrup urine disease family has been determined for the first time. The patient was found to be a compound heterozygote, inheriting an allele encoding an abnormal E1 alpha from the father, and an allele which is not expressed from the mother. The only known animal model for the disease (Polled Hereford cattle) has also been characterized. The mutation in these animals introduces a stop codon in the leader peptide of the E1 alpha subunit, resulting in premature termination of translation. Two thiamine responsive patients have been studied. The deduced amino acid sequences of the mature E1 alpha subunit and its leader sequence were normal, suggesting that the defect in these patients must exist in some other subunit of the complex. 3-Hydroxyisobutyrate dehydrogenase and methylmalonate-semialdehyde dehydrogenase, two enzymes of the valine catabolic pathway, were purified from liver tissue and characterized.(ABSTRACT TRUNCATED AT 400 WORDS)

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1989

Nutritional and hormonal regulation of the activity state of hepatic branched-chain alpha-keto acid dehydrogenase complex.

The hepatic branched-chain alpha-keto acid dehydrogenase complex plays an important role in regulating branched-chain amino acid levels. These compounds are essential for protein synthesis but are toxic if present in excess. When dietary protein is deficient, the hepatic enzyme is present in the inactive, phosphorylated state to allow conservation of branched-chain amino acids for protein synthesis. When dietary protein is excessive, the enzyme is in the active, dephosphorylated state to commit the excess branched-chain amino acids to degradation. Inhibition of protein synthesis by cycloheximide, even when the animal is starving for protein, results in activation of the hepatic branched-chain alpha-keto acid dehydrogenase complex to prevent accumulation of branched-chain amino acids. Likewise, the increase in branched-chain amino acids caused by body wasting during starvation and uncontrolled diabetes is blunted by activation of the hepatic branched-chain alpha-keto acid dehydrogenase complex. The activity state of the hepatic branched-chain alpha-keto acid dehydrogenase complex is regulated in the short term by the concentration of branched-chain alpha-keto acids (inhibitors of branched-chain alpha-keto acid dehydrogenase kinase) and in the long term by alteration in the total branched chain alpha-keto acid dehydrogenase kinase activity.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗