Reduction of extracellular methemoglobin by erythrocytes.

Erythrocytes, suspended in a glucose-containing buffer, catalyzed the partial reduction of extracellular methemoglobin. Physiological concentrations of ascorbic acid or dehydroascorbic acid greatly enhanced the rate of reaction and the ultimate extent of reduction. The relationship between erythrocyte concentration and initial reaction rate was nonlinear, which suggested that the rate limiting factor was not an erythrocyte membrane enzyme.

Hypertonic saline/dextran improves renal function after hemorrhage in conscious swine.

This study was performed to determine whether resuscitation with a single bolus of 7.5% NaCl/6% Dextran 70 (hypertonic saline/Dextran, HSD) could restore renal function following hemorrhage. Chronically instrumented, conscious pigs were hemorrhaged 28 ml/kg.

Sequential changes in alanine metabolism following partial hepatectomy in the rat.

After partial hepatectomy, the liver undergoes an array of metabolic changes until regeneration is complete. Since carbons derived from alanine can be incorporated into most metabolic pools, we studied the metabolism of (14)C-labeled alanine during the early phase of regeneration. Sham operated (controls) and partially hepatectomized rats weighing about 200 g each were injected intraperitoneally with 1-[U-(14)C]alanine at 9, 18, and 36 hours after surgery.

Increased vitamin E content in the lung after ozone exposure: a possible mobilization in response to oxidative stress.

Vitamin E (vE) is a biological free radical scavenger capable of providing antioxidant protection depending upon its tissue content. In previous studies, we observed that vE increased significantly in rat lungs after oxidant exposure, and we postulated that vE may be mobilized to the lung from other body sites under oxidative stress. To test this hypothesis, we fed Long-Evans rats either a vE-supplemented or a vE-deficient diet, injected them intraperitoneally with 14C-labeled vE, and then exposed half of each group to 0.

High-performance liquid chromatographic evaluation of pyridoxyl 5'-phosphate hemoglobin derivatives produced by different reduction procedures.

Pyridoxylated hemoglobin derivatives have been studied by many investigators. In this study hemoglobin A0 rather than stroma-free hemoglobin was used as a starting material in order to reduce the number of proteins to A0 and A1c. Derivatives were characterized using a Synchropak Q300 strong anion-exchange column, a PolyCAT A weak cation-exchange column and a VYDAC reversed-phase high-performance liquid chromatographic column.

[14C]mechlorethamine binding to proteins of the human keratinocyte.

Much mustard agent research has focused on mustard/DNA interactions. Mustard also interacts with proteins, however, and to reach the DNA any agent must first pass through the cytoplasm. We hypothesized that the cell's proteins would covalently bind mustard, and thereby limit its access to the DNA.

Attraction of mosquitoes to diethyl methylbenzamide and ethyl hexanediol.

Studies by prior workers have shown that insect repellents can act as attractants when present as low concentrations, deposits or residues. In the present study deet and ethyl hexanediol were tested in 2-fold serial doses from 1.9 X 10(-9) to 1.

Wounding effects of the AK-47 rifle used by Patrick Purdy in the Stockton, California, schoolyard shooting of January 17, 1989.

The limited disruption produced in tissue simulant by the rifle and bullets used in the Stockton, California, schoolyard shooting is entirely consistent with the autopsy reports on the five children who died of their wounds. It is also entirely consistent with well-documented battlefield studies and with previous tissue-simulant studies from many laboratories. It is inconsistent with many exaggerated accounts of assault-rifle wounding effects described by the media in the aftermath of this incident.

Relative binding constants of arsenical-antidote adducts determined by NMR spectroscopy.

Proton nuclear magnetic resonance spectroscopy was used to determine relative binding constants for several arsenical-antidote adducts. It was found that BAL (2,3-dimercaptopropanol) and DMPS (2,3-dimercaptopropanesulfonic acid) had a higher affinity than DMSA (2,3-dimercaptosuccinic acid) for the two organic arsenicals studied.

Blood gas and acid-base status of conscious pigs subjected to fixed-volume hemorrhage and resuscitated with hypertonic saline dextran.

Conscious, chronically instrumented pigs were subjected to a progressive, fixed-volume hemorrhage (37.5 ml/kg over 1 h) and subsequent resuscitation with 7.5% hemorrhage (37.

Superiority of hypertonic saline/dextran over hypertonic saline during the first 30 min of resuscitation following hemorrhagic hypotension in conscious swine.

We compared the effectiveness of intravenously administering hypertonic saline/dextran (HSD; 7.5% NaCl in 6% Dextran-70, n = 6) to hypertonic saline (HS) alone (7.5% NaCl, n = 8) in rectifying detrimental effects of hemorrhage on cardiovascular function.

Resistance of permethrin to weathering in fabrics treated for protection against mosquitoes (Diptera: Culicidae).

Two different methods of treating cotton and nylon-cotton fabrics with permethrin were evaluated for protection from mosquito bites after laboratory weathering. Cotton fabric treated by the individual dynamic absorption method provided consistently better protection than cotton fabric treated by the aerosol method. The nylon-cotton fabric provided similar protection regardless of the treatment method.

Quantitation of polymorphonuclear leukocyte adherence to endothelial cells by electronic particle size discrimination.

A method for quantitating the number of polymorphonuclear leukocytes (PMNs) adhering to endothelial cells in vitro is presented. Confluent human umbilical vein endothelial cells cultured in 24-well multiplates and treated with tumor necrosis factor alpha (TNF alpha) were incubated subsequently with PMNs which adhere to the endothelial cell as a function of TNF alpha concentration. Adherent PMNs and endothelial cells were proteolytically dissociated from the multiwell and, using an electronic particle counter, the number of endothelial cells and PMNs were determined simultaneously on the basis of size.

A method for isolating neutrophils from moderate volumes of human blood.

The Flow Laboratories procedure for isolating polymorphonuclear leukocytes (PMNs) from human blood whereby whole blood is centrifuged through Mono-Poly resolving medium (MPRM) has been modified. Using this modification, as much as 30 ml of whole blood could be processed in a single centrifuge tube, and erythrocyte contamination of the final PMN suspension was reduced significantly. PMN suspensions were composed of 96% neutrophils, and neutrophil recovery was 42-55% depending upon the volume of blood processed.

Mutagenic potential of permethrin in the Drosophila melanogaster (Diptera: Drosophilidae) sex-linked recessive lethal test.

When permethrin was tested for mutagenicity in Drosophila melanogaster Meigen with the sex-linked recessive lethal test, it was nonmutagenic under conditions of this study. The frequencies of spontaneous mutation for permethrin and the negative control were 0.135% and 0.

Determination of the oximes 2-hydroxyiminomethyl-3-methyl-1-[2-(3-methyl- 3-nitrobutyloxymethyl)]imidazolium chloride and 1-[1-(3-butynyloxymethyl)]-2-hydroxyiminomethyl-3-methylimida zolium chloride in plasma by high-performance liquid chromatography.

An assay is presented for the extraction and quantitation of two oximes, 2-hydroxyimino-methyl-3-methyl-1-[2-(3-methyl-3-nitrobutyloxyme thyl)] imidazolium chloride (oxime A) and 1-[1-(3-butynyloxymethyl)]-2-hydroxyiminomethyl-3-methylimidazo lium chloride (oxime B), in human plasma and is demonstrated to be linear over two overlapping concentration ranges: 10-500 and 100-1000 ng/ml. The assay utilizes a liquid-liquid, ion-pair extraction and a normal-phase chromatographic separation on a silica column with ultraviolet detection at 270 nm. The method is sensitive, rapid and accurate.

Normal physiological values for conscious pigs used in biomedical research.

Although the domestic pig is rapidly becoming an animal of choice in certain areas of biomedical research requiring a large animal model, effective utilization of the species is often encumbered by a lack of reference values for common functional variables. To address this problem, normal data for over 100 physiologic or related variables were collected from conscious chronically instrumented animals that were maintained under near basal conditions. Included were measurements of body composition, fluid volumes, blood physical and biochemical characteristics, blood gas and acid-base status, plasma hormone levels, energy metabolism, renal function, hemodynamics and pulmonary function.

Reexamination of the polymerization of pyridoxylated hemoglobin with glutaraldehyde.

Pyridoxylated adult human hemoglobin (HbAo) was prepared using a one molar equivalent of pyridoxal 5-phosphate (PLP) per heme and reduced with either NaCNBH3 or NaBH4. A separate sample was pyridoxylated and passed through a mixed-bed ion exchange column without reduction. All three preparations had a P50 of 29 +/- 2 torr and a cooperativity of n = 2.

Stress protein synthesis in human keratinocytes treated with sodium arsenite, phenyldichloroarsine, and nitrogen mustard.

Cells from bacteria to man respond to sublethal thermal and certain chemical stresses by synthesis of heat shock, or stress, proteins. The human epidermal keratinocyte is a target for a variety of cytotoxic substances. One response of cells exposed to such agents may be the synthesis of stress proteins.

Automated assays for superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity.

Automated assays for catalase, glutathione peroxidase, glutathione reductase, and superoxide dismutase are presented. The assay for catalase is based on the peroxidatic activity of the enzyme. The glutathione peroxidase and reductase assays measure the consumption of NADPH following the reduction of t-butyl hydroperoxide and oxidized glutathione, respectively.

Morphologic effects of hypervolemic administration of DBBF hemoglobin in the rat.

Conscious rats were given either 14 g/dl bis(3,5-dibromosalicyl) fumarate cross-linked hemoglobin (DBBF-Hb) in lactated Ringer's (LR) as an intravenous bolus (40, 50, or 60% of blood volume), 12.5 g/dl human serum albumin (HSA) in LR as a control for oncotic effects, or LR as a control for injection volume. The high dose HSA and DBBF-Hb rats experienced pulmonary edema after injection; one rat in each of these groups died soon after dosing.

Morphologic alterations in rat retina after hypervolemic infusion of cross-linked hemoglobin.

Hypervolemic infusion in rats of bis (3,5-dibromosalicyl) fumarate cross-linked hemoglobin (DBBF-Hb) to 40-60% of blood volume produced histologic lesions in retina which were not observed in rats similarly infused with human serum albumin or lactated Ringer's solution. Rats treated with 40% DBBF-Hb, exhibited intermittent zones of dense retinal pigmented epithelium while 60% DBBF-Hb animals exhibited severe inner retinal edema and retinal pigmented epithelium vacuolization, large focal zones of photoreceptor outer segment disruption and in one animal, subretinal hemorrhage. Light microscopic immunocytochemical evaluation of retinas with antibodies directed to human hemoglobin and albumin, showed the presence of both hemoglobin and albumin in this tissue.

Coronary vasoconstrictor activity of purified and modified human hemoglobin.

Unpurified stroma-free hemoglobin (SFH) from water-lysed human red blood cells, hemoglobin Ao (HbAo), and hemoglobin cross-linked between alpha chains with 3,5-bis-dibromosalicyl-fumarate (HbXLDBBF) were infused into isolated perfused rabbit hearts. Vasoactivity and myocardial performance were determined using an isovolumic Langendorff preparation. With constant coronary flow, infusion of SFH (55 mg/dl) resulted in a 56% increase in aortic pressure as opposed to 29% and 11% increases with HbAo and HbXLDBBF, respectively.

Liver and kidney injury after administration of hemoglobin cross-linked with bis(3,5-dibromosalicyl) fumarate.

Human hemoglobin cross-linked between the alpha chains with bis (3,5-dibromosalicyl) fumarate (DBBF-Hb) was exchange transfused in swine and the histomorphologic changes were evaluated. Following exchange, animals were euthanized and tissues were taken for light and electron microscopy at 7.5 hours and days 1, 4, 7, and 15.