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Veterinary medicine has made tremendous progress for domestic dogs, which are irreplaceable family members enriching human life. Nevertheless, no adequate supply system exists for their blood products. This study examined the synthesis, structure, safety, and efficacy of poly(2-ethyl-2-oxazoline)-conjugated porcine serum albumin (POx-PSA) as an artificial plasma expander for dogs. The aqueous POx-PSA solution showed moderately high colloid osmotic pressure and good blood cell compatibility. Actually, lyophilized powder stored for 1 year can regenerate into a homogeneous solution. The circulation half-life of POx-PSA in rats was 2.1-fold longer than that of naked PSA. Rats produced neither anti-PSA IgG antibody nor anti-POx IgG antibody, which suggests excellent immunological stealth properties of POx-PSA. Complete resuscitation of hemorrhagic shock in rats was achieved soon after injection of POx-PSA solution. Serum biochemistry tests and histopathological observations indicated no abnormality in the related organs. When POx-PSA was administered to dogs intravenously, (i) no serum biochemical or hematological alteration was observed, also (ii) no overt deterioration of animal health was observed. These results indicate that POx-PSA has potential as an artificial plasma expander for dogs. [ABSTRACT FROM AUTHOR]

Myoglobin combined with human serum albumin (Mb‐HSA) can be produced using yeast Pichia pastoris as a host strain, with secretion into the culture medium. This Mb‐HSA fusion protein possesses identical O2 binding affinity to that of naked Mb. The Mb unit is reconstituted with a zinc(II) protoporphyrin IX, yielding (zinc substituted Mb)‐HSA, ZnMb‐HSA. The photophysical property and singlet O2 generation ability of ZnMb‐HSA are equivalent to those of ZnMb. In vitro cell experiments revealed that ZnMb‐HSA acts as a superior photosensitizer for photodynamic cancer therapy. It is noteworthy that ZnMb‐HSA shows long circulation lifetime in vivo. [ABSTRACT FROM AUTHOR]

A bovine hemoglobin (HbBv) or human adult hemoglobin (HbA) wrapped covalently by human serum albumins (HSAs), hemoglobin–albumin clusters (HbBv–HSA3 and HbA–HSA3), are artificial O2 carriers used as a red blood cell substitute. This article describes the physicochemical properties of the HbBv–HSA3 and HbA–HSA3 solutions, and their abilities to restore the systemic condition after resuscitation from hemorrhagic shock in anesthetized rats. The HbBv–HSA3 and HbA–HSA3, which have high colloid osmotic activity, showed equivalent solution characteristics and O2 binding parameters. Shock was induced by 50% blood withdrawal. Rats exhibited hypotension and significant metabolic acidosis. After 15 min, the rats were administered shed autologous blood (SAB), HbBv–HSA3, HbA–HSA3, or Ringer's lactate (RL) solution. Survival rates, circulation parameters, hematological parameters, and blood gas parameters were monitored during the hemorrhagic shock and for 6 h after administration. All rats in the SAB, HbBv–HSA3, and HbA–HSA3 groups survived for 6 h. The HbBv–HSA3 and HbA–HSA3 groups restored mean arterial pressure after the resuscitation. No remarkable difference was observed in the time courses of blood gas parameters in any resuscitated group except for the RL group. Serum biochemical tests showed increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HbBv–HSA3 and HbA–HSA3 groups compared to the SAB group. Therefore, we observed other rats awakened after resuscitation with HbA–HSA3 for 7 days. The blood cell count, AST, and ALT recovered to the baseline values by 7 days. All the results implied that HbBv–HSA3 and HbA–HSA3 clusters provide restoration from hemorrhagic shock as an alternative material for SAB transfusion. [ABSTRACT FROM AUTHOR]

Re-expansion of a collapsed lung increases the microvascular permeability and causes reexpansion pulmonary edema. Neutrophils and their products have been implicated in the development of this phenomenon. The small GTP-binding proteins Rho and its target Rho-kinase (ROCK) regulate endothelial permeability, although their roles in reexpansion pulmonary edema remain unclear. We studied the contribution of ROCK to pulmonary endothelial and epithelial permeability in a rabbit model of this disorder. Endothelial and epithelial permeability was assessed by measuring the tissue-to-plasma (T/P) and bronchoalveolar lavage (BAL) fluid-to-plasma (B/P) ratios with [sup.125I]-1abeled albumin. After intratracheal instillation of [sup.125I]-albumin, epithelial permeability was also assessed from the plasma leak (PL) index, the ratio of [sup.125I]-albumin in plasma/total amount of instilled [sup.125I]-albumin. T/P, B/P, and PL index were significantly increased in the reexpanded lung. These increases were attenuated by pretreatment with Y-27632, a specific ROCK inhibitor. However, neutrophil influx, neutrophil elastase activity, and malondialdehyde concentrations in BAL fluid collected from the reexpanded lung were not changed by Y-27632. In endothelial monolayers, Y-27632 significantly attenuated the [H.sub.2][O.sub.2]-induced increase in permeability and mitigated the morphological changes in the actin microfilament cytoskeleton of endothelial cells. These in vivo and in vitro observations suggest that the Rho/ ROCK pathway contributes to the increase in alveolar barrier permeability associated with reexpansion pulmonary edema. acute lung injury; acute respiratory distress syndrome; re-expansion pulmonary edema; Rho; Rho-kinase

We examined the effects of prolonged hyperoxia (75% [O.sub.2]) on lung structure and collagen metabolism in the subacute phase of lung injury induced by continuous infusion of endotoxin (LPS) in a rat model. Experimental groups included control, endotoxin alone, endotoxin plus hyperoxia, and byperoxia alone. Endotoxin-treated rats received a bolus of LPS (10 mg/kg iv) followed by 500 [micro]g x [kg.sup.-1] x [day.sup.-1] in continuous infusion for 10 days. The bronchoalveolar lavage (BAL) fluid/plasma albumin concentration ratio, an index of capillary permeability, and neutrophil and macrophage counts in BAL fluid were highest in the endotoxin plus hyperoxia group. On pathological examination, prolonged hyperoxia exacerbated destruction of the alveolar wall and caused most prominent emphysematous changes in the endotoxin plus hyperoxia group. Lung tissue hydroxyproline concentration was significantly decreased in the hyperoxia group and increased in the endotoxin group. The latent forms of MMP-2 and MMP-9 increased in BAL fluid of the endotoxin- and/or hyperoxia-treated groups, whereas the activities of collagenase and gelatinase, and the active form of MMP-2 were all increased in the hyperoxia-treated groups. Added to endotoxin, prolonged hyperoxia degraded collagen, the major structural component of basement membranes, and caused emphysematous changes associated with activation of collagenase and MMP-2. Our observations suggest that, in the subacute phase of endotoxin-induced lung injury, prolonged hyperoxia causes pulmonary emphysematous changes with persistent injury to the alveolar capillary barrier. Collagenase and MMP-2 activated by byperoxia, together with MMP-9, may play prominent roles in disruption of the alveolar basement membranes and degradation of collagen lining the alveolar walls. emphysema; matrix metalloproteinase