An analog of the human albumin N-terminus (Asp-Ala-His-Lys) prevents formation of copper-induced reactive oxygen species.

Copper mobilization and redox activity form damaging reactive oxygen species (ROS) and are implicated in the pathogenesis of ischemia-reperfusion injury, chronic inflammation, Alzheimer's disease, aging, and cancer. Protein sequestration of Cu(II) ions has been shown to prevent ROS-generating reactions. The first four amino acids of the N-terminus of human albumin, Asp-Ala-His-Lys (DAHK), form a tight binding site for Cu(II) ions. We synthesized several analogs, including the enantiomer d-DAHK, to study their effects on copper-induced hydroxyl radical and superoxide formation in the presence of ascorbate. d-DAHK prevented thiobarbituric acid-reactive species (TBARS) formation within physiological and acidic pH ranges (7.5-6.5) and inhibited low-density lipoprotein lipid peroxidation. A d-DAHK/Cu complex exhibited superoxide dismutase-like activity by significantly inhibiting superoxide formation. These in vitro results suggest that d-DAHK may shift the Cu(II)-binding equilibrium from the exchangeable Cu(II) pool to the tightly-bound, nonexchangeable pool, prevent ROS formation, and potentially provide therapeutic benefit for ROS-related diseases.

Reduced albumin-cobalt binding with transient myocardial ischemia after elective percutaneous transluminal coronary angioplasty: a preliminary comparison to creatine kinase-MB, myoglobin, and troponin I.

BACKGROUND: Previous reports suggest that ischemic conditions rapidly reduce the capacity of human albumin to bind exogenous cobalt. A new assay based on human albumin-cobalt binding (ACB) may help detect early myocardial ischemia. We investigated altered ACB during the first 24 hours after transient ischemia induced during elective percutaneous transluminal coronary angioplasty (PTCA). We then compared ACB assay results with creatine kinase isoenzyme (CK-MB), myoglobin, and cardiac troponin I (cTn-I) values after PTCA. METHODS AND RESULTS: In 41 patients undergoing elective PTCA, plasma samples were tested for the ACB assay, CK-MB, myoglobin, and cTn-I before, immediately after, and 6 and 24 hours after PTCA. Thirteen additional patients served as a control group with albumin-cobalt assays performed before and after diagnostic coronary catheterization without angioplasty. ACB assay results demonstrated a significant mean percent difference (10.1%) immediately after PTCA compared with baseline (P < .000001) and returned to baseline by 6 hours after PTCA. ACB assay differences immediately after PTCA were significantly greater than in the control group (10.1% vs -0.9%, P < .001). Mean CK-MB, myoglobin, and cTn-I values were not elevated above baseline immediately after PTCA but were significantly elevated above baseline 6 and 24 hours after PTCA. CONCLUSIONS: These preliminary results suggest that human albumin undergoes a significant reduction in its capacity to bind exogenous cobalt soon after transient coronary occlusion during human PTCA and before significant elevations of CK-MB, myoglobin, or cTn-I. Further confirmatory investigations are warranted to determine if the ACB assay is a useful diagnostic test for early myocardial ischemia.

Asp-Ala-His-Lys (DAHK) inhibits copper-induced oxidative DNA double strand breaks and telomere shortening.

Both DNA and the telomeric sequence are susceptible to copper-mediated reactive oxygen species (ROS) damage, particularly damage attributed to hydroxyl radicals. In this study, ROS-induced DNA double strand breaks and telomere shortening were produced by exposure to copper and ascorbic acid. Asp-Ala-His-Lys (DAHK), a specific copper chelating tetrapeptide d-analog of the N-terminus of human albumin, attenuated DNA strand breaks in a dose dependent manner. d-DAHK, at a ratio of 4:1 (d-DAHKCu), provided complete protection of isolated DNA from double strand breaks and, at a ratio of 2:1 (d-DAHKCu), completely protected DNA in Raji cells exposed to copper/ascorbate. Southern blots of DNA treated with copper/ascorbate showed severe depletion and shortening of telomeres and Raji cell treated samples showed some conservation of telomere sequences. d-DAHK provided complete telomere length protection at a ratio of 2:1 (d-DAHKCu). The human albumin N-terminus analog, d-DAHK, protects DNA and telomeres against copper-mediated ROS damage and may be a useful therapeutic adjunct in ROS disease processes.

A novel assay for cobalt-albumin binding and its potential as a marker for myocardial ischemia-a preliminary report.

We initially observed a phenomenon of reduced in vitro binding of exogenous cobalt [Co(II)] to the N-terminus of human serum albumin (HSA) in emergency chest pain patients with early onset unstable angina and myocardial infarction. We then developed a colorimetric assay to measure cobalt-HSA binding and record the results in absorbance units (ABSU). In a preliminary clinical study of 139 emergency patients with acute chest pain, 99 patients with evidence of myocardial ischemia (Group 1) had elevated assay levels (mean ABSU +/- SD; 0.519 +/- 0.086) compared to 40 patients (Group 2) with no evidence of ischemia (0.316 +/- 0.092) (p < 0.00001). In Group 1, 95 of 99 (96.0%) patients had levels higher than a decision threshold of 0.400 ABSU and in Group 2, 37 of 40 (92.5%) samples had higher cobalt binding capacity (ABSU

Protracted metabolic acidosis: the impact of acute ethanol in hemorrhagic shock.

The effects of acute ethanol administration on acid-base balance and hemodynamic parameters were studied in a canine model. Ten mongrel dogs, anesthetized and maintained on a volume ventilator, underwent splenic artery ligation 30 minutes prior to study. Group A (N = 5) served as controls. Thirty minutes after drug administration, the animals underwent a 20-cc/kg hemorrhage over 15 minutes. Thirty minutes postphlebotomy, resuscitation was performed with the same volume of homologous blood. Acid-base and hemodynamic parameters were monitored over 3.5 hours. Ethanol levels peaked 60 minutes following administration at 207 +/- 13 mg%. During the entire study, no differences were observed in heart rate, pulmonary capillary wedge pressure, systemic vascular resistance index, pO2, or pCO2, between the two groups. Following hemorrhage, statistically significant decreases in pH, mean arterial pressure (MAP), cardiac index (CI), and left ventricular stroke work index (LVSWI) developed in group A compared to controls. Maximal disparity developed in pH (7.21 +/- 0.05 to 7.33 +/- 0.02, P < 0.01), MAP (67 +/- 11 v 110 +/- 9 torr, P < 0.01), CI (1.69 +/- 0.24 compared to 2.72 +/- 0.19 L/min/M2, and LVSWI (18.7 +/- 1.2 compared to 44.9 +/- 4.8 gr-meter/M2/beat, P < 0.01) at 60, 45, 30, and 75 minutes postphlebotomy. In this study, ethanol directly or indirectly caused an increased metabolic acidosis and myocardial depression in the post-hemorrhage period.

Mothball differentiation: naphthalene from paradichlorobenzene.

In order to develop a rapid, simple test to differentiate toxic naphthalene from the less toxic mothball ingredient paradichlorobenzene, both types of mothballs were dissolved in isopropyl alcohol, ethanol, methanol, and turpentine. Twenty-five naphthalene and 25 paradichlorobenzene mothballs were weighed, randomly grouped, and then dissolved in the solvents. After 30 minutes, the mothballs were reweighed. Isopropyl alcohol, ethanol, and methanol did not differentially dissolve the mothballs fast enough to provide a useful test. Turpentine, however, dissolved paradichlorobenzene at a much more rapid rate than naphthalene (P less than .001). After 60 minutes, all of the paradichlorobenzene mothballs had dissolved, while at least 25% of the naphthalene remained. Thus, when confronted with an ingestion of unlabeled mothballs, the physician could gain preliminary information regarding possible toxicity by dissolving a remaining mothball in turpentine for 60 minutes.

Naloxone: effects on hypoxic pulmonary vasoconstriction.

To determine the effect of naloxone on the hypoxic pulmonary vasoconstrictive response, six mongrel dogs were rendered hypoxic with 10% oxygen and were given either saline or naloxone. Following hypoxia all dogs had significant increases in mean pulmonary artery pressure (PAP) and pulmonary arterial resistance index (PARI) without changes in cardiac output or systemic blood pressure. Beta endorphins did not change at any time following hypoxia. Dogs receiving naloxone had significant lowering of PAP and PARI without changes in plasma beta endorphin levels. We conclude that naloxone attenuates hypoxic pulmonary vasoconstriction without measurable alterations of plasma beta endorphin levels.

Prehospital use of the Glasgow Coma Scale in severe head injury.

To determine the prognostic value of prehospital Glasgow Coma Scale (GCS) scores in severe blunt head injuries, the GCS at the scene of injury (INGCS) and the GCS in the emergency department (EDGCS) were compared with neurologic outcomes in 33 consecutive head-injured patients. Patients were categorized according to final outcome: Group I (n = 7) had no neurologic deficits, group II (n = 3) had only minor neurologic deficits, group III (n = 11) had major neurologic deficits, and group IV (n = 12) died. Mean INGCS was not significantly different for any of the four groups (range 4.14 to 4.67). However, mean EDGCS was significantly higher (P less than .05) for group I (9.43 +/- 4.08) than for group IV (5.17 +/- 3.13), and mean EDGCS for groups I and II (8.8 +/- 3.99) were significantly higher (P less than .05) than that of groups III and IV (5.7 +/- 2.88). The net change in GCS (EDGCS--INGCS) was significantly higher (P less than .05) for groups I and II (4.5 +/- 4.4) than for groups III and IV (1.3 +/- 2.91). We conclude that INGCS alone has no prognostic value, but that EDGCS and any prehospital change in GCS may have prognostic value for severely head-injured patients.

Relative lack of coronary blood flow during closed-chest resuscitation in dogs.

Recent studies have shown that blood flow during closed-chest cardiopulmonary resuscitation (CPR) results primarily from generalized changes in intrathoracic pressure rather than direct compression of the heart. Since ascending aortic and right atrial pressures rise and fall synchronously and to comparable levels during CPR, we hypothesized that the absence of a pressure difference across the coronary vascular bed during CPR precludes coronary blood flow. To test this hypothesis, we compared high-fidelity ascending aortic and right atrial pressures and carotid and coronary blood flow (electromagnetic flowmeters) during closed-chest CPR in 12 fibrillating dogs. Chest compression force was increased from 40 to 140 pounds in 20-pound increments using a pneumatic chest compression device. Although ascending aortic and right atrial pressures were always similar, high-compression-force CPR produced small mean pressure differences across the coronary vascular bed (5.6 +/- 0.8 mm Hg [+/- SEM] at 140 pounds). These pressure differences were accompanied by low levels of coronary blood flow. However, coronary flow was less than 1% control (prearrest) values whenever chest compression force was less than 100 pounds, and carotid flow exceeded coronary flow under all conditions (carotid and coronary flows at 140 pounds = 26.2 +/- 6.4% and 4.3 +/- 2.0% of prearrest values, respectively, p less than 0.01). We conclude that generalized changes in intrathoracic vascular pressures during closed-chest CPR promote carotid but not coronary blood flow. High-compression-force CPR produces small pressure differences across the coronary vascular bed, allowing low levels of coronary flow. However, even high-compression-force CPR is over six times more effective in maintaining carotid flow than coronary flow.