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C Ogle

Publications and source records attributed to C Ogle.

8 recordsLinked to original sources
PubMed1995

Burn injury stimulates multiple proteolytic pathways in skeletal muscle, including the ubiquitin-energy-dependent pathway.

BACKGROUND: Burn injury is associated with increased muscle protein breakdown. However, the role of different intracellular proteolytic pathways in burn-induced muscle proteolysis is not known. STUDY DESIGN: A 30 percent total body surface area burn injury was inflicted on rats. Total and myofibrillar proteolysis was determined in incubated extensor digitorum longus muscles as release of tyrosine and 3-methylhistidine, respectively. Lysosomal proteolysis was assessed by using the lysosomotropic agents leupeptin and methylamine. Calcium-dependent proteolysis was determined by incubating muscles in the absence or presence of calcium or by blocking the calcium-dependent proteases calpain I and II. Energy-dependent proteolysis was determined in muscles depleted of adenosine triphosphate (ATP) by 2-deoxyglucose and 2,4-dinitrophenol. Muscle ubiquitin messenger RNA (mRNA) was determined by Northern blot analysis to assess ATP-ubiquitin-dependent proteolysis. RESULTS: Calcium-dependent total protein breakdown was stimulated in muscles from burned rats. However, the sensitivity to calcium in vitro was not increased after burn. The lysosomal and energy-dependent components of total protein breakdown were doubled in muscles from burned rats and the energy-dependent myofibrillar protein breakdown was increased almost seven-fold. Ubiquitin mRNA was increased in muscles from burned rats. CONCLUSIONS: Burn injury stimulates multiple proteolytic pathways in skeletal muscle. The ubiquitin-energy-dependent pathway may be particularly important for the breakdown of myofibrillar proteins.

Animals↗
PubMed1995

Influence of burn injury on protein metabolism in different types of skeletal muscle and the role of glucocorticoids.

BACKGROUND: Negative nitrogen balance after burn injury mainly indicates muscle catabolism, but the exact influence of burn on protein synthesis and breakdown in different types of skeletal muscle and the role of glucocorticoids in this metabolic response are unknown. STUDY DESIGN: A 30 percent body surface area flame burn was inflicted on rats. Protein turnover rates were measured in vitro in the white fast-twitch extensor digitorum longus (EDL) muscle and the red slow-twitch soleus muscle. To test the role of glucocorticoids, groups of rats were treated with the glucocorticoid receptor antagonist RU 38486 or vehicle. RESULTS: Burns resulted in reduced protein synthesis and stimulated protein breakdown, in particular myofibrillar protein breakdown, and the changes were substantially more pronounced in the EDL than in the soleus muscle. A burn-induced increase in muscle proteolysis was abolished by treatment with RU 38486, whereas the reduced protein synthesis was not affected by the glucocorticoid receptor antagonist. CONCLUSIONS: The results suggest that the white fast-twitch muscle is more sensitive to the effects of burn injury than the red slow-twitch muscle. Burn-induced muscle proteolysis may be mediated, at least in part, by glucocorticoids, whereas protein synthesis is probably regulated by other mechanisms.

Animals↗
PubMed1994

Detrimental effect of nitric oxide synthase inhibition during endotoxemia may be caused by high levels of tumor necrosis factor and interleukin-6.

BACKGROUND: Nitric oxide (NO) production increases during sepsis and endotoxemia. Inhibition of NO synthase has been suggested as a therapeutic modality in sepsis and endotoxemia, but in recent reports NO synthase inhibition increased mortality rate. The mechanism of this phenomenon is not known. Other studies have shown that high levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6) contribute to death during sepsis and endotoxemia. We tested the effect of NO synthase inhibition on survival in endotoxemic rats and hypothesized that inhibition of NO synthase during endotoxemia increases circulating levels of TNF and IL-6. METHODS: Rats were treated with subcutaneous injection of saline solution or 100 mg/kg of the NO synthase inhibitor N-nitro-L-arginine 1 hour before intravenous injection of endotoxin (15 mg/kg) or saline solution. Survival was followed for 24 hours. Plasma nitrite-nitrate (NO2/NO3), TNF, and IL-6 levels were determined at intervals. RESULTS: Endotoxin caused a significant increase in levels of plasma NO2-/NO3-, TNF, and IL-6 and a 33% mortality rate. Pretreatment with N-nitro-L-arginine increased mortality rate to 74%, decreased NO2/NO3, and substantially increased TNF and IL-6 levels. CONCLUSIONS: Inhibition of NO synthase increases mortality rate during endotoxemia. The detrimental effect of NO synthase inhibition during endotoxemia may be caused by excessive production of TNF and IL-6.

Amino Acid Oxidoreductases↗
PubMed1989

Diclofenac.

Diclofenac is the newest NSAID to be introduced to the United States. Extensive worldwide clinical studies with diclofenac have demonstrated its efficacy in the treatment of rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. Its overall safety and efficacy is comparable to other available NSAIDs. The potential advantage of diclofenac is its short serum half-life but long synovial fluid concentration which enables twice daily dosing.

Diclofenac↗
PubMed1987

Superoxide dismutase in rats with sepsis. Effect on survival rate and amino acid transport.

In a recent study, administration of the free radical scavenger superoxide dismutase (SOD) improved survival in rats with sepsis when administered two hours before induction of sepsis. The present study was designed to determine whether free radical-induced membrane damage is involved in the pathogenesis of decreased muscle amino acid uptake, noted in sepsis. Additionally, the effect on survival rate of SOD given after the onset of sepsis was studied. Sepsis was induced by cecal ligation and puncture in rats. Amino acid transport in incubated soleus muscles was studied using tritiated alpha-aminoisobutyric acid. Amino acid uptake was significantly reduced in muscle from rats with sepsis. Administration of SOD before induction of sepsis or added in vitro to incubated muscles with sepsis had no effect on alpha-aminoisobutyric acid uptake. Survival rate was not increased when SOD was given two hours after cecal ligation and puncture. The results suggest that free radical-induced membrane damage is not the mechanism of inhibited muscle amino acid transport in sepsis. Since survival was not improved by SOD administered after induction of sepsis, the role of the enzyme in the treatment of sepsis may be questioned.

Amino Acids↗
PubMed1987

Evaluation of serum proteins in relation to body nitrogen in tumor-bearing rats.

Assessment of visceral and somatic protein stores by serum proteins in surgical oncology patients has been difficult to interpret. Tumor-bearing (methylcholanthrene sarcoma) (TB) and nontumor-bearing (NTB) Fischer 344 rats were infused with a total parenteral nutrition solution at either 25, 100, or 175% of an infusion rate that provided sufficient nutrients for normal rat growth: On the fifth day after diet initiation, the rats were exsanguinated, decapitated, eviscerated, and skinned. Serum was analyzed for transferrin (TF), complement C3, albumin (ALB), retinol-binding protein (RBP), and transthyretin (TTR). Carcass (CAR) and organ (VIS) nitrogens were determined by the Kjeldahl method. TTR, TF, and RBP correlated significantly with TB and NTB VIS nitrogen and TB CAR nitrogen. The correlation of NTB VIS nitrogen with TTR, TF, and RBP (r range = 0.70-0.85, P less than 0.001) was higher than for TB rats (r range = 0.53-0.57, P less than 0.005). The correlation of TB carcass nitrogen (r range = 0.47-0.51, P less than 0.01) with TTR, TF, and RBP was higher than for NTB carcass nitrogen which was not significant (r range = 0.25-0.37, P less than 0.57). These data indicate that TTR, TF, and RBP do correlate with components of body nitrogen mass, but factors other than nutrition may influence their metabolism in the TB host.

Animals↗
PubMed1986

Reduced muscle amino acid uptake in sepsis and the effects in vitro of septic plasma and interleukin-1.

Inhibited amino acid transport in skeletal muscle during sepsis has been demonstrated previously. In the present study we investigated the effects in vitro of plasma from septic animals or fractions of septic plasma that contain solutes with a molecular weight less than 30,000 daltons or less than 2000 to 3000 daltons on amino acid transport in incubated rat soleus (SOL) muscles. The influence of interleukin-1 (IL-1), prostaglandin E2 (PEG2), and the "catabolic" hormones corticosterone, glucagon, and epinephrine on muscle amino acid uptake was also investigated. Amino acid transport was studied with 3H-alpha-aminoisobutyric acid (AIB). Whole-septic plasma and the two low molecular-weight fractions of the septic plasma reduced muscle amino acid uptake by about 20%. IL-1 or PGE2 did not affect amino acid transport. When the catabolic hormones were added individually to incubated SOL muscles, no changes in AIB uptake were noticed. When glucagon or epinephrine was added in combination with corticosterone or when all three hormones were added together, amino acid transport was reduced by 10% to 15%. The results suggest that inhibited muscle amino acid uptake in sepsis is caused by a circulating factor(s) with a molecular weight less than 2000 to 3000 daltons. A synergistic action among the catabolic hormones may be one important factor for reduced muscle amino acid transport in sepsis.

Amino Acids↗