Prognostic utility of neuroinjury biomarkers in post out-of-hospital cardiac arrest (OHCA) patient management.

Despite aggressive intervention, patients who survive an out-of-hospital cardiac arrest (OHCA) generally have very poor prognoses, with nationwide survival rates of approximately 10-20%. Approximately 90% of survivors will have moderate to severe neurological injury ranging from moderate cognitive impairment to brain death. Currently, few early prognostic indicators are considered reliable enough to support patients' families and clinicians' in their decisions regarding medical futility. Blood biomarkers of neurological injury after OHCA may be of prognostic value in these cases. When most bodily tissues are oxygen-deprived, cellular metabolism switches from aerobic to anaerobic respiration. Neurons are a notable exception, however, being dependent solely upon aerobic respiration. Thus, after several minutes without circulating oxygen, neurons sustain irreversible damage, and certain measurable biomarkers are released into the circulation. Prior studies have demonstrated value in blood biomarkers in prediction of survival and neurologic impairment after OHCA. We hypothesize that understanding peptide biomarker kinetics in the early return of spontaneous circulation (ROSC) period, especially in the setting of refractory cardiac arrest, may assist clinicians in determining prognosis earlier in acute resuscitation. Specifically, during and after immediate resuscitation and return of ROSC, clinicians and families face a series of important questions regarding patient prognosis, futility of care and allocation of scarce resources such as the early initiation of extracorporeal cardiopulmonary resuscitation (ECPR). The ability to provide early prognostic information in this setting is highly valuable. Currently available, as well as potential biomarkers that could be good candidates in prognostication of neurological outcomes after OHCA or in the setting of refractory cardiac arrest will be reviewed and discussed.

Opposite effects of metallothionein I and spermine on mitochondrial function.

Previously, we reported that the stress-induced protein metallothionein I (MT) modulated the oxygen consumption (VO2) of isolated rat liver mitochondria [Life Sci. 55 221-226, 1994]. We now present confirmation of this finding, and the additional observations that in rat liver mitochondria, MT caused swelling and depolarization. These actions of MT were inhibited by the aliphatic polyamine, spermine. Our findings suggest that mitochondrial function could be influenced by the balance between MT and spermine.

Polyclonal antibodies raised against Bacillus Calmette-Guerin, Mycobacterium duvalii, and Mycobacterium paratuberculosis used to detect mycobacteria in tissue with the use of immunohistochemical techniques.

Commercially available polyclonal antibodies raised against strains of mycobacteria were used to detect organisms in tissue sections from 34 cases of tuberculosis, leprosy, and atypical mycobacteria. Thirty-two cases of fungal infections, granulomatous inflammation, and sarcoidosis were used as negative controls. Sections stained with the use of antibodies raised against Bacillus Calmette-Guerin (BCG), Mycobacterium duvalii (MD), and Mycobacterium paratuberculosis (MP) were compared with Kinyoun and Fite-stained tissue sections. In caseating granulomata, clumps of mycobacterial debris, cells, and cell fragments stained. In histiocytic granulomata of mycobacterial infections, histiocyte cytoplasm contained both organisms and debris. The three antibodies showed cross-reactivity against the four groups of mycobacteria tested. Mycobacterial staining using immunoperoxidase was apparent in most cases at low-power (scanning) magnification. Thirty-two of 34 cases of mycobacterial infection, including all 24 Kinyoun-Fite-positive cases, were positive for immunoreactive organisms and debris using anti-MD, anti-BCG, and/or anti-MP. Eight of ten cases of culture-proven mycobacterial infection, in which Kinyoun and Fite stains were negative, had immunoreactive organisms or antigen with anti-BCG, MD, or MP. The antibodies also stained organisms in five cases of sporotrichosis in which the organisms were identified as yeast forms in tissue sections.

Structural evidence for leucine at the reactive site of heparin cofactor II.

The reaction products formed during the enzymatic inactivation of heparin cofactor II (HCII) by a proteinase isolated from Echis carinatus were analyzed by sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gel electrophoresis and by reverse-phase high-performance liquid chromatography. By NaDodSO4-polyacrylamide gel electrophoresis, limited proteolysis of HCII was observed, which resulted in a decrease in the apparent molecular weight of the protein from approximately 68 000 to approximately 53 000. By reverse-phase high-performance liquid chromatography, at least 20 peptides were observed. Primary structure analysis of these peptides indicated that significant proteolysis had occurred in the NH2-terminal region of the protein. HCII inactivation, however, coincided with the appearance of a peptide from the COOH-terminal region of the protein. The peptide differed from the previously identified reactive site peptide [Griffith, M. J., Noyes, C. M., & Church, F. C. (1985) J. Biol. Chem. 260, 2218-2225] by only one residue: a leucyl residue at the NH2-terminal of the peptide. We conclude that leucine, as opposed to the expected arginine, is at the reactive site of HCII.

Enzymatic inactivation of heparin cofactor II by a proteinase (proteinase-1) isolated from Echis carinatus venom.

Heparin cofactor II was enzymatically inactivated by incubation with Echis carinatus venom in the presence of calcium. The initial rate of inactivation increased proportionately with the addition of heparin to a final concentration of 50 micrograms/ml. A proteinase, termed proteinase-1, was purified 17.5-fold from the venom which also enzymatically inactivated heparin cofactor II in the presence of calcium. The initial rate of heparin cofactor II inactivation by proteinase-1 was not increased by heparin at concentrations as high as 200 micrograms/ml. Heparin cofactor II was not inactivated by either unfractionated venom or proteinase-1 in the absence of calcium. The results indicate that heparin cofactor II, like antithrombin III, is susceptible to enzymatic inactivation by metalloproteinases in snake venoms.