ABSTRACT
This corrects the article DOI: 10.1038/pcan.2017.5.
ABSTRACT
BACKGROUND: Surgery and radiation-based therapies are standard management options for men with clinically localized high-risk prostate cancer (PCa). Contemporary patterns of care are unknown. We hypothesize the use of surgery has steadily increased in more recent years. METHODS: Using the National Cancer Data Base for 2004-2013, all men diagnosed with high-risk localized PCa were identified using National Comprehensive Cancer Network criteria. Temporal trends in initial management were assessed. Multivariable logistic regression was used to evaluate demographic and clinical factors associated with undergoing radical prostatectomy (RP). RESULTS: In total, 127 391 men were identified. Use of RP increased from 26% in 2004 to 42% in 2013 (adjusted risk ratio (RR) 1.51, 95% CI 1.42-1.60, P<0.001), while external beam radiation therapy (EBRT) decreased from 49% to 42% (P<0.001). African American men had lower odds of undergoing RP (unadjusted rate of 28%, adjusted RR 0.69, 95% CI 0.66-0.72, <0.001) compared to White men (37%). Age was inversely associated with likelihood of receiving RP. Having private insurance was significantly associated with the increased use of RP (vs Medicare, adjusted odds ratio 1.04, 95% CI 1.01-1.08, P=0.015). Biopsy Gleason scores 8-10 with and without any primary Gleason 5 pattern were associated with decreased odds of RP (vs Gleason score ⩽6, both P<0.001). Academic and comprehensive cancer centers were more likely to perform RP compared to community hospitals (both P<0.001). CONCLUSION: The likelihood of receiving RP for high-risk PCa dramatically increased from 2004 to 2013. By 2013, the use of RP and EBRT were similar. African American men, elderly men and those without private insurance were less likely to receive RP.
Subject(s)
Prostatic Neoplasms/surgery , Aged , Disease Management , Humans , Insurance, Health , Kaplan-Meier Estimate , Male , Middle Aged , Multivariate Analysis , Odds Ratio , Proportional Hazards Models , Prostatectomy/statistics & numerical data , Prostatic Neoplasms/mortality , Prostatic Neoplasms/pathology , Prostatic Neoplasms/radiotherapy , United StatesABSTRACT
Intensity modulated radiation therapy (IMRT) has achieved widespread use for prostate cancer; however, in relation to this use, outcomes studies are still relatively sparse. We report a single-institutional experience in outcomes analysis with the use of IMRT for the primary management of prostate cancer. One hundred thirty consecutive patients with adenocarcinoma of the prostate were treated at a single institution using IMRT with curative intent. Thirty-six (28%) patients were classified as low-risk, 69 (53%) as intermediate-risk, and 25 (19%) as high-risk. The median dose prescription was 76 Gy to the planning target volume. Sixty-five (50%) patients received androgen deprivation therapy (ADT) for a median 4 months, starting 2 months prior to IMRT. Biochemical failure was defined as PSA < post-treatment nadir+2. Gastrointestinal (GI) and Genitourinary (GU) toxicity were defined by RTOG criteria. Median follow-up was 53 months. By NCCN risk category, 4-year biochemical control was 97%, 94%, and 87% for low, intermediate, and high-risk patients, respectively. Among disease factors, multivariable analysis demonstrated the strongest association between biochemical control and Gleason score < or =6 (p=0.0371). Therapy was well tolerated with no Grade 4 toxicity and limited grade 3 GI or GU toxicity. Acute Grade 3+ GI and GU toxicity rates were 0% and 2%, and maximal late Grade 3+ GI and GU toxicity rates were 5% and 6%, respectively. Late rectal toxicity was associated with higher volumes of RT to the rectum. By last follow-up late Grade 3+ toxicity was 2% for both GI and GU systems. In conclusion, patients treated with IMRT for prostate cancer have excellent rates of biochemical control and low rates of severe toxicity of treatment.
Subject(s)
Prostatic Neoplasms/radiotherapy , Radiotherapy, Intensity-Modulated/adverse effects , Aged , Aged, 80 and over , Gastrointestinal Tract/radiation effects , Humans , Male , Middle Aged , Multivariate Analysis , Urogenital System/radiation effectsABSTRACT
To utilize the Surveillance, Epidemiology, and End Results (SEER) registry to examine trends in grade assignment. Data from 411 325 patients from 1984 to 2003 were analyzed for grade migration and for cause-specific survival (CSS) as a function of grade. There has been a significant grade migration during the study period (P<0.001), principally from well-differentiated (WD) to moderately differentiated (MD) disease. Five-year CSS of MD and WD patients have converged, suggesting a decreasing role of grade as a prognostic factor. A grade migration from WD to MD assignment has occurred, suggesting that prognostic categorizations based on grade across eras may be difficult to interpret.
Subject(s)
Prostatic Neoplasms/pathology , Registries , SEER Program/statistics & numerical data , Adult , Aged , Aged, 80 and over , Cell Differentiation , Humans , Male , Middle Aged , Neoplasm Staging , Prognosis , Prostatic Neoplasms/epidemiology , Survival RateABSTRACT
cAMP analogues, systematically substituted at position 8 of the adenine moiety (C8), were tested quantitatively for binding to each cAMP interaction site (A and B) of the regulatory subunits of cAMP-dependent protein kinase type I (RI) and II (RII). Site AII did not accommodate cAMP analogues with any bulk at position 8, whereas site AI accepted even bulky 8-substituents. This implies that the narrow, buried pocket of site AI facing position C8 of cAMP in the RI-cAMP crystal [Su, Y., Dostmann, W. R., Herberg, F. W., Durick, K., Xuong, N. H., Ten Eyck, L., Taylor, S. S., and Varughese, K. I. (1995) Science 269, 807-813] must undergo considerable conformational change and still support high-affinity cAMP analogue binding. The B sites of RI and RII differed in three respects. First, site BI had a lower affinity than site BII for cAMP analogues with hydrophobic, bulky 8-substituents. Second, site BI had a preference for substituents with hydrogen bonding donor potential close to C8, whereas site BII had a preference for substituents with hydrogen bonding acceptor potential. This implies that Tyr(371) of RI and the homologous Tyr(379) of RII differ in their hydrogen bonding preference. Third, site BI preferred analogues with a positively charged amino group that was an extended distance from C8, whereas site BII discriminated against a positive charge. The combined results allow refinement of the cAMP binding site geometry of RI and RII in solution, and suggest design of improved isozyme-specific cAMP analogues.
Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Cyclic AMP/analogs & derivatives , Animals , Binding Sites , Cattle , Cyclic AMP/chemistry , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/chemistry , Hydrogen Bonding , Isoenzymes/chemistry , Isoenzymes/metabolism , Kinetics , Molecular Conformation , Muscle, Skeletal/enzymology , Myocardium/enzymology , Rabbits , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Phosphorylation of the catalytic subunit of cyclic AMP-dependent protein kinase, or protein kinase A, on Thr-197 is required for optimal enzyme activity, and enzyme isolated from either animal sources or bacterial expression strains is found phosphorylated at this site. Autophosphorylation of Thr-197 occurs in Escherichia coli and in vitro but is an inefficient intermolecular reaction catalyzed primarily by active, previously phosphorylated molecules. In contrast, the Thr-197 phosphorylation of newly synthesized protein kinase A in intact S49 mouse lymphoma cells is both efficient and insensitive to activators or inhibitors of intracellular protein kinase A. Using [35S]methionine-labeled, nonphosphorylated, recombinant catalytic subunit as the substrate in a gel mobility shift assay, we have identified an activity in extracts of protein kinase A-deficient S49 cells that phosphorylates catalytic subunit on Thr-197. The protein kinase A kinase activity partially purified by anion-exchange and hydroxylapatite chromatography is an efficient catalyst of protein kinase A phosphorylation in terms of both a low Km for ATP and a rapid time course. Phosphorylation of wild-type catalytic subunit by the kinase kinase activates the subunit for binding to a pseudosubstrate peptide inhibitor of protein kinase A. By both the gel shift assay and a [gamma-32P]ATP incorporation assay, the enzyme is active on wild-type catalytic subunit and on an inactive mutant with Met substituted for Lys-72 but inactive on a mutant with Ala substituted for Thr-197. Combined with the results from mutant subunits, phosphoamino acid analysis suggests that the enzyme is specific for phosphorylation of Thr-197.
Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Protein Serine-Threonine Kinases/metabolism , Threonine/metabolism , Amino Acid Sequence , Animals , Cyclic AMP-Dependent Protein Kinases/biosynthesis , Escherichia coli/metabolism , Gene Expression , Mice , Molecular Sequence Data , Phosphorylation , Tumor Cells, CulturedABSTRACT
Sequential ischemia/reperfusion in a paired canine gracilis muscle model resulted in significant muscle salvage. In this model, one randomly chosen gracilis muscle was subjected to 5 h of ischemia followed by 48 h of in vivo reperfusion. The contralateral (second) muscle was then made ischemic and reperfused using the same protocol. Muscle necrosis was determined at the end of 48 h of reperfusion. A mean 60% reduction in muscle necrosis was observed in the second group of muscles. Analysis of tissue adenine nucleotides indicated that significant sparing of ATP utilization occurred in the second muscle group during ischemia. Preliminary analysis of tissue heat shock proteins (HSP) showed that the second group of muscles had a different pattern of HSP expression before the onset of ischemia. The results suggest that reduced ATP utilization and altered HSP expression in the second muscle play a role in the tissue salvage observed in this sequential muscle ischemia model.
Subject(s)
Ischemia/physiopathology , Muscle, Skeletal/blood supply , Muscle, Skeletal/physiopathology , Reperfusion , Adenosine Triphosphate/metabolism , Animals , Dogs , Female , Heat-Shock Proteins/metabolism , Ischemia/pathology , Male , Muscle, Skeletal/pathology , NecrosisABSTRACT
Thr-197 phosphate is essential for optimal activity of the catalytic (C) subunit of cAMP-dependent protein kinase enzyme, and, in the C subunit crystal structure, it is buried in a cationic pocket formed by the side chains of His-87, Arg-165, Lys-189, and Thr-195. Because of its apparent role in stabilizing the active conformation of C subunit and its resistance to several phosphatases, the phosphate on Thr-197 has been assumed to be metabolically stable. We now show that this phosphate can be removed from C subunit by a protein phosphatase activity extracted from S49 mouse lymphoma cells or by purified protein phosphatase-2A (PP-2A) with concomitant loss of enzymatic activity. By anion-exchange chromatography, inhibitor sensitivity, and relative activity against glycogen phosphorylase a and C subunit as substrates, the cellular phosphatase resembled a multimeric form of PP-2A. PP-1 was ineffective against native C subunit, but it was able to dephosphorylate Thr-197 in urea-treated C subunit. Accessibility of Thr-197 phosphate to the cellular phosphatase was enhanced by storage of C subunit in a phosphate-free buffer or by inclusion of modest concentrations of urea in the reactions and was reduced by salt concentrations in the physiological range and/or by amino-terminal myristoylation. It is concluded that a multimeric form of PP-2A or a closely related enzyme from cell extracts is capable of removing the Thr-197 phosphate from native C subunit in vitro and could account for significant turnover of this phosphate in intact cells.
Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Phosphoprotein Phosphatases/metabolism , Threonine/metabolism , Animals , Catalysis , Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors , Cyclic AMP-Dependent Protein Kinases/chemistry , Enzyme Inhibitors/pharmacology , Ethers, Cyclic/pharmacology , Mice , Okadaic Acid , Osmolar Concentration , Phosphorylation , Protein Phosphatase 2 , Tumor Cells, CulturedABSTRACT
Reperfusion of ischemic skeletal muscle is associated with neutrophil (PMN) adherence to damaged endothelium and PMN-mediated tissue destruction. Neutrophils may attach to endothelium through surface adhesive molecules, such as CD18. The purpose of this study was to determine whether monoclonal antibody blockade of CD18 would reduce skeletal muscle necrosis associated with ischemia and reperfusion. In rabbits, an entire hindlimb was rendered ischemic for 4 hr, followed by 48 hr of in vivo reperfusion. Animals were allocated to one of five treatment groups: ischemia/reperfusion without treatment (I/R controls), I/R plus treatment with the anti-CD18 antibody IB4 (end-ischemic 2 mg/kg dose), I/R plus treatment with an identical dose of isotype-matched control Ig, I/R plus anterior compartment fasciotomy, or I/R plus both IB4 and fasciotomy. After 48 hr of reperfusion anterior tibial muscle necrosis was assessed (by tetrazolium staining and computerized planimetry), wet:dry muscle weights (W:D) were determined, and muscle PMN sequestration was measured by myeloperoxidase (MPO) activity. IB4-treated animals exhibited markedly reduced muscle MPO activity, compared to untreated animals. Although all interventions reduced edema formation (W:D ratios), none did so significantly. IB4 treatment reduced muscle necrosis when used alone (to 28 +/- 7%, vs. 48% +/- 6% in untreated controls), however this was not statistically significant (P = 0.06).2+ Fasciotomy significantly reduced necrosis (to 22 +/- 2%, P < 0.05); however, the addition of IB4 to fasciotomy resulted in necrosis that was significantly lower than that after fasciotomy alone (12 +/- 4%, P < 0.05 vs fasciotomy group) and the least necrosis of any group.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Antibodies, Monoclonal/therapeutic use , Antigens, CD/physiology , Ischemia , Muscles/blood supply , Reperfusion Injury/prevention & control , Animals , Antigens, CD/immunology , CD18 Antigens , Female , Muscles/pathology , Necrosis , Neutrophils/physiology , Organ Size , Peroxidase/metabolism , RabbitsABSTRACT
Reperfusion of ischemic skeletal muscle is associated with white blood cell (WBC) sequestration and hydroperoxy-conjugated diene (HCF) formation, a marker of free radical-mediated phospholipid peroxidation. The purpose of this study was to define the kinetics of phospholipid fatty acyl peroxidation, deacylation, and remodeling in postischemic skeletal muscle during prolonged reperfusion in vivo, and to determine whether reperfusion with WBC and plasma-depleted blood would attenuate postischemic phospholipid peroxidation and myocyte necrosis. The isolated, paired, canine gracilis muscle model was used. After 5 h of ischemia, muscles underwent unaltered reperfusion or initial reperfusion with WBC-deficient blood cells resuspended in hydroxyethyl starch, followed by return to normal circulation (modified reperfusion). The concentration of native fatty acids and HCDs of linoleic acid extracted from muscle phospholipids was quantified by gas chromatography and positively identified by mass spectrometry. Ischemia and reperfusion resulted in phospholipid deacylation and a selective increase in phospholipid stearic acid content, but had no effect on total phospholipid phosphorus. Modified reperfusion decreased 1) early HCD formation (54%) and 2) postischemic skeletal muscle necrosis (49%). These data suggest that reperfusion results in phospholipid deacylation and remodeling, and that the initial oxidant stress during reperfusion may be a significant determinant of ultimate muscle necrosis.
Subject(s)
Ischemia/metabolism , Lipid Peroxides/metabolism , Muscles/blood supply , Phospholipids/metabolism , Reperfusion , Acylation , Animals , Dogs , Fatty Acids, Unsaturated/metabolism , In Vitro Techniques , Ischemia/pathology , Muscles/metabolism , Muscles/pathology , Necrosis , Peroxidase/metabolism , Phospholipids/chemistry , Phosphorus/analysisABSTRACT
Skeletal muscle ischemia results in energy depletion and intracellular acidosis. Reperfusion is associated with impaired adenine nucleotide resynthesis, edema formation, and myocyte necrosis. The purpose of these studies was to define the time course of cellular injury and adenine nucleotide depletion and resynthesis in postischemic skeletal muscle during prolonged reperfusion in vivo. The isolated canine gracilis muscle model was used. After 5 h of ischemia, muscles were reperfused for either 1 or 48 h. Lactate and creatine phosphokinase (CPK) release during reperfusion was calculated from arteriovenous differences and blood flow. Adenine nucleotides, nucleosides, bases, and creatine phosphate were quantified by high-performance liquid chromatography, and muscle necrosis was assessed by nitroblue tetrazolium staining. Reperfusion resulted in a rapid release of lactate, which paralleled the increase in blood flow, and a delayed but prolonged release of CPK. Edema formation and muscle necrosis increased between 1 and 48 h of reperfusion (P less than 0.05). Recovery of energy stores during reperfusion was related to the extent of postischemic necrosis, which correlated with the extent of nucleotide dephosphorylation during ischemia (r = 0.88, P less than 0.001). These results suggest that both adenine nucleotide resynthesis and myocyte necrosis, which are protracted processes in reperfusing skeletal muscle, are related to the extent of nucleotide dephosphorylation during ischemia.
Subject(s)
Adenine Nucleotides/biosynthesis , Ischemia/metabolism , Muscles/blood supply , Reperfusion Injury/metabolism , Animals , Creatine Kinase/metabolism , Dogs , Ischemia/pathology , Lactates/metabolism , Lactic Acid , Muscles/metabolism , Muscles/pathology , Necrosis , Nitroblue Tetrazolium , Organ Size , Phosphocreatine/metabolism , Regional Blood Flow , Reperfusion Injury/pathology , Time FactorsABSTRACT
Primary radiotherapy for 127 early breast cancers produced five-year local control of 96.1 percent and NED results of 81.1 percent. Results from a large community cancer center in New Jersey are comparable to results of major university cancer centers.
Subject(s)
Breast Neoplasms/radiotherapy , Breast Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Combined Modality Therapy , Female , Follow-Up Studies , Humans , Middle Aged , Neoplasm Recurrence, Local , Neoplasm Staging , Survival RateABSTRACT
The clinical significance and applicability of interventions aimed at reducing reperfusion injury in postischemic skeletal muscle remain unproven, since long-term muscle salvage has not been demonstrated by most treatment protocols that attenuate early reperfusion injury. We have shown that reperfusion of ischemic skeletal muscle results in an early and prolonged sequestration of white blood cells and activation of the alternative complement cascade. The purpose of this study was to determine if 40 minutes of reperfusion with blood depleted of white blood cells and complement proteins, followed by 2 days of normal perfusion, would reduce muscle necrosis after 5 hours of ischemia. The isolated paired canine gracilis muscle model was used. The treatment muscle was initially reperfused with arterial blood that had been spun, washed, passed through a leukocyte removal filter, and resuspended in hydroxyethyl starch (greater than 99.9% removal of white blood cells and the complement proteins factor B and C4). The contralateral control muscle was subjected to unaltered reperfusion. Blood flow (ml/min/100 gm) was measured by timed collection of gracilis venous blood. Myeloperoxidase activity (absorbance at 655 nm/min/mg tissue protein) in muscle biopsies was used to monitor white blood cell sequestration. After 48 hours of reperfusion in vivo, necrosis was quantified by nitroblue tetrazolium staining. Initial reperfusion with white blood cell and complement depleted blood significantly reduced muscle necrosis (53% +/- 3% vs 29% +/- 8%, p less than 0.0025, paired t test). Early blood flow was improved, (p = 0.0025, repeated measure-ANOVA), but subsequent white blood cell sequestration was not altered (p = 0.33, repeated measure-ANOVA). This suggests that a significant amount of white blood cell mediated injury occurs during the first 40 minutes of reperfusion. Preventing early complement activation and white blood cell mediated reperfusion injury is an intervention that is feasible during surgery and may result in clinically significant salvage of postischemic skeletal muscle.
Subject(s)
Ischemia/therapy , Muscles/blood supply , Animals , Biopsy , Complement System Proteins/physiology , Dogs , Female , In Vitro Techniques , Ischemia/enzymology , Ischemia/pathology , Leukocytes/physiology , Male , Muscles/enzymology , Muscles/pathology , Necrosis/enzymology , Necrosis/pathology , Perfusion/methods , Peroxidase/analysis , Reperfusion/methods , Reperfusion Injury/enzymology , Reperfusion Injury/etiology , Reperfusion Injury/pathology , Time FactorsABSTRACT
After skeletal muscle ischemia, tissue damage is augmented during reperfusion. White blood cells (WBCs) and complement proteins may participate in the reperfusion injury. The purpose of this study was to define the kinetics of classical and alternative pathway complement activation and WBC sequestration by postischemic skeletal muscle during the first 48 h of reperfusion in vivo. The isolated canine gracilis muscle model was used. Systemic levels of the complement proteins factor B (alternative pathway) and C4 (classical pathway) were quantitated by hemolytic assay. WBC sequestration was measured by gracilis arterial-venous WBC differences and tissue myeloperoxidase activity. Reperfusion was associated with an 18% decrease in systemic factor B levels but no consistent change in systemic C4 levels. WBCs were sequestered during the first 4 h of reperfusion, and tissue myeloperoxidase activity was elevated 97-fold after 48 h of reperfusion. These results suggest that skeletal muscle ischemia-reperfusion stimulates 1) activation of the alternative but not the classical complement pathway and 2) an immediate and prolonged sequestration of WBCs.
Subject(s)
Complement Activation , Ischemia/blood , Leukocytes/physiology , Muscles/blood supply , Reperfusion , Animals , Complement C4/analysis , Complement Factor B/analysis , Dogs , Muscles/enzymology , Peroxidase/metabolismABSTRACT
Prolonged ischemia to skeletal muscle as occurs after an acute arterial occlusion results in alterations in adenine nucleotide metabolism. Adenosine triphosphate continues to be used for cellular functions, and an ischemia-induced degradation of phosphorylated adenine nucleotides is initiated. In this experiment we demonstrated the time-dependent aspect of adenine nucleotide depletion during ischemia and the production of large quantities of soluble precursors. In addition, we studied the rate of conversion of xanthine dehydrogenase to xanthine oxidase, a potential source of oxygen-free radicals, after controlled periods of total normothermic ischemia (4 hours and 5 hours) and during the reperfusion phase. During ischemia complete depletion of creatine phosphate occurred in both groups, and adenosine triphosphate fell from 22.1 +/- 1.3 to 10.3 +/- 1.4 mumol/gm dry weight after 4 hours and from 21.6 +/- 0.7 to 3.9 +/- 0.8 mumol/gm dry weight after 5 hours (p less than 0.05). During reperfusion, creatine phosphokinase resynthesis occurred in both groups, but adenosine triphosphate levels were not significantly increased (p greater than 0.05). A washout of lipid soluble products of adenine nucleotide metabolism occurred equally in both groups. The relationship between phosphorylated adenine nucleotides as measured by the energy charge potential fell significantly in both groups (p less than 0.05), but after the shorter period of ischemia (4 hours it returned to normal during early reperfusion but did not after 5 hours of ischemia. There was 21% +/- 4% necrosis after 4 hours and 51% +/- 8% after 5 hours of ischemic stress when assessed at 48 hours. In conclusion, the degree of adenine nucleotide degeneration as determined primarily by the length of the ischemic period, may be the most important determinant of the ultimate extent of skeletal muscle ischemic necrosis that results from an acute interruption of circulation.
Subject(s)
Adenine Nucleotides/metabolism , Ischemia/metabolism , Muscles/metabolism , Xanthine Oxidase/biosynthesis , Adenine Nucleotides/analysis , Animals , Dogs , In Vitro Techniques , Muscles/blood supply , Phosphocreatine/analysis , Purines/analysis , Xanthine Dehydrogenase/metabolismABSTRACT
The lower extremity may be exposed to prolonged periods of ischemia, resulting in depletion of intracellular energy stores in the affected skeletal muscle. The role of adenine nucleotide reduction and failure of resynthesis on reperfusion in determining the extent of muscle necrosis was investigated in this study, in addition to the possible beneficial effects of the addition of exogenous adenosine triphosphate-magnesium chloride during early reperfusion. The isolated paired canine gracilis muscle model was used. After 4 hours of normothermic ischemia in group I, a perfusate Krebs-Henseleit solution plus the gradual reintroduction of oxygenated blood flow was compared to standard reperfusion. In group II, a similar infusion protocol was used, with the addition of 2 mmol/L adenosine triphosphate-magnesium chloride and compared to normal reperfusion. Adenosine triphosphate-magnesium chloride resulted in the salvage of skeletal muscle, 57% +/- 12% versus 44% +/- 14% (p less than 0.05, n = 6 pairs). Reperfusion with the solution alone increased the resulting necrosis (42% +/- 13% vs 60% +/- 20%, n = 6 pairs). Adenine nucleotide stores were not increased, but oxygen consumption was increased by magnesium chloride-adenosine triphosphate (p less than 0.05, analysis of variance [ANOVA]). A clear relationship was demonstrated between the fall in energy stores, as measured by a change in energy charge potential from preischemia to end ischemia levels, and the extent of resulting necrosis (p less than 0.01). In summary, the addition of 2 mmol/L to an infusion of Krebs-Henseleit solution during reperfusion results in significant salvage of skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Adenosine Triphosphate/therapeutic use , Magnesium Chloride/therapeutic use , Muscles/blood supply , Reperfusion Injury/prevention & control , Adenine Nucleotides/metabolism , Animals , Dogs , Hindlimb/blood supply , Muscles/metabolism , Reperfusion/methodsABSTRACT
Changes in the skeletal muscle adenine nucleotide pool during prolonged periods of normothermic ischemia, followed by reperfusion are a result of an exaggerated breakdown to lipid soluble precursors, the degree of reactive hyperemia, and activities of the salvage and direct pathways for resynthesis. We show that the degree of breakdown of ATP, ADP and AMP, is time dependent, and with restoration of circulation there is washout of these lipid soluble precursors, and no resynthesis of ATP. We demonstrated a relationship between the loss of energy during ischemia, and the degree of resultant necrosis, suggesting that a limit on the effectiveness of therapeutic interventions during reperfusion in reducing the extent of necrosis may exist.