Platelet preservation in large containers

The influence of the size of the container on platelet concentrate storage at 20-24 degrees C was examined. Baseline studies were obtained with 50 platelet concentrates in 300-ml PL-146 plastic containers. Experimental studies included 6 platelet concentrates each in 300-, 600- and 2,000-ml containers made of PL-146 plastic. Platelet count, total platelets, pO2, pCO2, pH, glucose consumption, lactate production, platelet morphology and recovery by platelets to osmotic stress were monitored during storage. During storage, the best pH and morphology values were observed with 2,000-ml containers. The lowest glucose consumption and lactate production were also associated with the 2,000-ml containers. Intermediate improvement in these parameters was noted in 600-ml containers. Recovery from osmotic stress was better in 2,000- and 600-ml containers as compared to 300-ml containers. In addition, characteristic changes in pO2 and pCO2 during storage suggest that improved platelet preservation in larger containers is due to improved gas exchange conditions obtained with increased surface area available for gas exchange.     

Decreased Hemolysis and Lipid Peroxidation in Blood during Storage in the Presence of Nicotinic Acid

BACKGROUND AND OBJECTIVES: There is increase in lipid peroxidation with consequent increase in hemolysis when blood is stored in di-(2-ethyl hexyl)phthalate (DEHP) plasticized bags. Studies carried out by us and others have indicated the ability of red cells to synthesize NAD+ from added nicotinic acid. Apart from the role of NAD+ in glycolysis, NADPH is required for reduction of oxidized glutathione to its reduced form by glutathione reductase. Reduced glutathione is an important antioxidant, which protects cell membrane from oxidative damage. Reduced glutathione is also involved in the regeneration of vitamin E, another important membrane antioxidant. In view of these, a study was undertaken to find out the effect of addition of nicotinic acid to the citrate-phosphate-dextrose-adenine (CPDA) solution on lipid peroxidation and integrity of red cells when whole blood is stored in DEHP plasticized bags. MATERIALS AND METHODS: Blood was collected in Penpol blood storage bags (which is a DEHP plasticized bag) in CPDA solution in the presence and absence of nicotinic acid. Various parameters of lipid peroxidation and membrane stability - level of malondialdehyde (MDA), conjugated dienes, vitamin E, reduced glutathione, plasma Hb and K+, levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) were studied in the blood samples after various periods. RESULTS: Plasma Hb and K+ concentrations were significantly lower in the presence of added nicotinic acid both after 28 and 42 days. Concentration of MDA and conjugated dienes was lower and the levels of reduced glutathione and vitamin E higher in the presence of nicotinic acid. ATP levels were not significantly different, but 2,3-DPG levels were higher. pH of the blood was nearer to 7.0 in the presence of nicotinic acid, while leaching out of DEHP into the blood was significantly lower. CONCLUSION: Inclusion of nicotinic acid in the CPDA solution has a beneficial effect in that (1) it reduces plasma Hb and K+; (2) reduces lipid peroxidation and increases antioxidant protection; (3) maintains pH nearer to 7.0, and (4) decreases the leaching out of DEHP into the blood.     

Effect of Centrifugation on the Storage Properties of Platelets

Some of the recommended centrifugation methods for the preparation of platelet concentrates may cause accelerated deterioration of platelets stored in second-generation containers. The deterioration is characterized by increasing pH, pO2 and decreasing pCO2, a high discharge of lactate dehydrogenase (LDH) and increasing amounts of small particles which have recently been shown to have platelet factor 3 activity [Solberg, C.; Osterud, B.; Little, C.: Thrombosis Res. 48: 559-565, 1987]. A short first centrifugation (3,270 g, 2 min 15 s) yielded platelets with better storage properties than platelet-rich plasma prepared with longer centrifugation times (2,200 g, 4 min 30 s and 1,100 g, 6 min). By using multivariate data analysis the effect of different platelet concentrations and metabolic parameters can be used to predict the discharge of LDH or the change in morphology.     

Effect of hydrosoluble coenzyme Q10 on blood pressures and insulin resistance in hypertensive patients with coronary artery disease

In a randomised, double-blind trial among patients receiving antihypertensive medication, the effects of the oral treatment with coenzyme Q10 (60 mg twice daily) were compared for 8 weeks in 30 (coenzyme Q10: group A) and 29 (B vitamin complex: group B) patients known to have essential hypertension and presenting with coronary artery disease (CAD). After 8 weeks of follow-up, the following indices were reduced in the coenzyme Q10 group: systolic and diastolic blood pressure, fasting and 2-h plasma insulin, glucose, triglycerides, lipid peroxides, malondialdehyde and diene conjugates. The following indices were increased: HDL-cholesterol, vitamins A, C, E and beta-carotene (all changes P<0.05). The only changes in the group taking the B vitamin complex were increases in vitamin C and beta-carotene (P<0.05). These findings indicate that treatment with coenzyme Q10 decreases blood pressure possibly by decreasing oxidative stress and insulin response in patients with known hypertension receiving conventional antihypertensive drugs.     

Lactic acid concentration and acid-base balance in cerebrospinal fluid: observations of diagnostic importance in non-Hodgkin lymphoma

Measurements of lactic acid concentration and gas analysis were performed in lumbar cerebrospinal fluid from 36 patients without malignant central nervous system involvement and four patients with meningeal dissemination of non-Hodgkin lymphoma. The upper lactic acid concentration in controls of 2.48 mmol/l was exceeded in all four patients, also in cases with low blast counts and normal protein and glucose content. The pH, pCO2, pO2 and standard bicarbonate concentration in spinal fluid of patients with meningeal dissemination in non-Hodgkin lymphoma did not show significant differences compared with other patients and controls. Determination of the lactic acid concentration in cerebrospinal fluid add information, relevant to the diagnosis of meningeal involvement in non-Hodgkin lymphoma.     

Lipid peroxidation and hepatic antioxidants in alcoholic liver disease

The generation of hepatic liver peroxidation by free radicals has been proposed as a mechanism for ethanol induced hepatotoxicity. To investigate this hypothesis, lipid extracts from hepatic needle biopsy specimens from alcoholic subjects were examined for evidence of lipid peroxidation by measuring total conjugated dienes by derivative spectroscopy and, after hydrolysis of hepatic lipid extract and reverse phase high performance liquid chromatography, the molar ratio between a diene-conjugated linoleic acid isomer (18:2 (9,11)) and the parent linoleic acid isomer (18:2(9,12)). Changes were related to hepatic histology, iron deposition, glutathione and vitamin E values. Derivative spectroscopy minima suggestive of diene conjugation were identified at 233 and 242 nm and correlated weakly, suggesting these two minima may represent different classes of lipid dienes. There was a weak relation with inflammatory histological changes in the biopsy specimen but no correlation with hepatic iron grade, glutathione, or vitamin E lipid ratio. The proportion of 18:2(9,11) linoleic acid in hepatic lipids correlated significantly with inflammatory histological features and inversely with hepatic glutathione. Furthermore, hepatic glutathione was lower in biopsy specimens with greater iron staining. The ratio of vitamin E to lipid was not related to histological group, inflammation, or iron grade. These findings suggest that excess alcohol consumption leads to hepatic inflammation and lipid peroxidation.     

Effect of coenzyme Q10 on experimental atherosclerosis and chemical composition and quality of atheroma in rabbits

The effects of the administration of coenzyme Q10 (3 mg/kg per day) (group A, n=10) and placebo (aluminum hydroxide, 3 mg/kg per day) (group B, n=10) were compared over 24 weeks in a randomized, single-blind, controlled trial. There were two groups of rabbits receiving a trans fatty acid (TFA)-rich diet (5-8 g/day) for 36 weeks. Oxidized rabbit chow with vitamin C plus ferric chloride was administered for 4 weeks in all rabbits. Intervention with coenzyme Q10 after feeding of TFA-rich diet was associated with a significant decline in thiobarbituric acid reactive substances (TBARS), diene conjugates and malondialdehyde, and an increase in plasma levels of vitamin E in the coenzyme Q group compared to placebo group. These changes, which were indicators of a decrease in oxidative damage, were independent of lipid lowering. The aortic and coronary artery plaque sizes, coronary atherosclerosis index, aortic and coronary atherosclerosis scores were significantly lower in the coenzyme Q group than placebo group. Aortic and coronary plaque frequencies, as well as frequencies of ulceration, thrombosis or hemorrhage, and cracks and fissures, were also significantly lower in the coenzyme Q group, indicating a better quality of atheroma compared to those in the control group. Aortic cholesterol, triglycerides and sudanophilia were significantly lower and vitamin E significantly higher in the coenzyme Q group in comparison to the placebo group indicating that coenzyme Q10 can have beneficial effect on the chemical composition of atheroma. The findings suggest that antioxidant therapy with coenzyme Q10 may be used as an adjunct to lipid lowering for additional beneficial effects related to chemical composition and quality of atheroma independent of hypolipidemic agents.     

Inhibition of adriamycin-induced human platelet lipid peroxidation by vitamin E

Adriamycin® is an important cancer chemotherapeutic agent whose clinical use is compromised by potentially lethal cardiotoxicity. In the mouse, cardiotoxicity is related to the peroxidation of cardiac lipids. Both phenomena, however, can be reduced by pretreatment of the animal with vitamin E. Using the platelet as our model we have demonstrated that Adriamycin induces lipid peroxidation of human platelets in a dose-dependent manner. Platelet malonyldialdehyde (MDA) production was used as an indicator of lipid peroxidation. Adriamycin at 5, 10, 50, and 100 μg/ml produced 1.40 ± 0.2 (1 SD), 2.23 ± 0.41, 4.23 ± 0.4, and 6.13 ± 0.43 nmoies MDA per 10⁹ platelets, respectively. Vitamin E both in vitro and in vivo inhibited this lipid peroxidation. In vitro, vitamin E at concentrations of 0.01, 0.05, and 0.1 mg/ml inhibited platelet MDA formation by 14 ± 2, 29 ± 5, and 38 ± 6%, respectively. In six controls who ingested 1,600 units vitamin E daily for two weeks, platelet MDA formation induced by N-ethyl maleimide, thrombin, and Adriamycin was decreased by 11-20%. In similar studies, the ingestion of 10 grains acelyl salicylic acid (ASA) also inhibited platelet lipid peroxidation induced by these same agents. ASA and vitamin E were not additive in their inhibition of MDA formation induced by N-ethyl maleimide or thrombin. They were additive, however, in their inhibition of Adriamycin-induced lipid peroxidation, which suggests that the effect of vitamin E on Adriamycin-induced platelet lipid peroxidation is not due to inhibition of platelet cyclooxygenase. In the light of these observations on the inhibitory effect of vitamin E on lipid peroxidation in human platelets, further studies appear warranted on the clinical effects of E in inhibiting cardiac lipid peroxidation and concomitant cardiotoxicity in humans on Adriamycin therapy.     

Increased Lipid Peroxidation of Erythrocytes in Blood Stored in Polyvinyl Chloride Blood Storage Bags Plasticized with Di-[2-Ethyl Hexyl] Phthalate and Effect of Antioxidants

Background and Objectives : Previous work in this laboratory has shown significant decrease in vitamin E in erythrocytes in blood stored in polyvinyl chloride (PVC) bags plasticized with di-[2-ethyl hexyl] phthalate (DEHP), and in erythrocytes incubated in vitro with DEHP. Since vitamin E is a major antioxidant, a study was carried out to find out whether this decrease observed in vitamin E has an effect on lipid peroxidation in blood stored in DEHP-plasticized PVC blood bags. Materials and Methods : Blood was collected in Penpol blood storage bags (which is a DEHP-plasticized PVC bag) and parameters of lipid peroxidation, i.e. activity of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, concentration of malondialdehyde (MDA), conjugated dienes, hydroperoxides, glutathione and vitamin E studied in erythrocytes after various periods of storage as compared to glass bottles. Erythrocytes were also incubated in vitro with DEHP with and without vitamin E, and changes in lipid peroxidation studied. Results :Blood stored in Penpol bags showed increased lipid peroxidation in erythrocytes as compared to that stored in glass bottles, as is evident from a greater increase in MDA and a greater decrease in glutathione and a significant decrease in vitamin E. The addition of vitamin E decreased the formation of MDA and conjugated dienes and prevented the decrease in vitamin E. However in spite of increased lipid peroxidation in the presence of DEHP, the release of K⁺ and hemoglobin from erythrocytes was lower. When there was an increase in DEHP taken up by erythrocytes, there was a corresponding decrease in vitamin E. More important, whenever there was an increase in vitamin E in erythrocytes (when RBCs in the presence of DEHP were incubated with vitamin E), there was a progressive decrease in DEHP. Conclusion : DEHP caused increased lipid peroxidation in erythrocytes. At the same time, it decreased the release of K⁺ and hemoglobin from erythrocytes. It is possible that the stabilizing effect of DEHP on the erythrocyte membrane may offset the detrimental effects of the increased lipid peroxidation it causes.     

Requirement for coenzyme Q in plasma membrane electron transport.

Coenzyme Q is required in the electron transport system of rat hepatocyte and human erythrocyte plasma membranes. Extraction of coenzyme Q from the membrane decreases NADH dehydrogenase and NADH:oxygen oxidoreductase activity. Addition of coenzyme Q to the extracted membrane restores the activity. Partial restoration of activity is also found with alpha-tocopherylquinone, but not with vitamin K1. Analogs of coenzyme Q inhibit NADH dehydrogenase and oxidase activity and the inhibition is reversed by added coenzyme Q. Ferricyanide reduction by transmembrane electron transport from HeLa cells is inhibited by coenzyme Q analogs and restored with added coenzyme Q10. Reduction of external ferricyanide and diferric transferrin by HeLa cells is accompanied by proton release from the cells. Inhibition of the reduction by coenzyme Q analogs also inhibits the proton release, and coenzyme Q10 restores the proton release activity. Trans-plasma membrane electron transport stimulates growth of serum-deficient cells, and added coenzyme Q10 increases growth of HeLa (human adenocarcinoma) and BALB/3T3 (mouse fibroblast) cells. The evidence is consistent with a function for coenzyme Q in a trans-plasma membrane electron transport system which influences cell growth.     

Sustained elevation of intracellular cyclic 3'-5' adenosine monophosphate is necessary for preservation of platelet integrity during long-term storage at 22 degrees C

Preservation of platelet integrity and responsiveness was examined in platelet concentrates prepared in the presence of various formulations and combinations of platelet-activation inhibitors affecting intracellular levels of cyclic 3'-5' adenosine monophosphate (cAMP). Platelet concentrates were prepared and stored in an artificial medium for two weeks at 22 degrees C. Markers of metabolic activity (pH, lactate, pO2, pCO2 in the medium), aggregation response, hypotonic shock response, and glycoprotein Ib (GPIb) expression were assessed along with direct measurements of cAMP in platelet pellets and thromboxane B2 (TxB2) in the supernate. The platelet concentrates prepared with only adenylate-cyclase stimulators (prostaglandin E-1 or forskolin) showed less maintenance of the integrity and responsiveness markers and greater loss of GPIb than concentrates prepared with phosphodiesterase inhibitors (theophylline or caffeine) or combinations with the above. These results were correlated with the ability of these compounds to sustain elevation of cAMP above basal level during the entire extended-storage period. The strong correlation (rs = -0.67) between elevation of cAMP levels and suppression of TxB2 production suggests that the phosphodiesterase inhibitors provided better protection than stimulators of adenylate cyclase alone through a reduction in platelet activation and its deleterious effects on preservation of platelets during storage.     

Functional characteristics of S-59 photochemically treated platelet concentrates derived from buffy coats

BACKGROUND: A photochemical treatment (PCT) process for inactivation of infectious pathogens and leukocytes has been developed and evaluated using single-donor platelet concentrates. This study assessed the application of PCT to platelets prepared from pooled buffy coats. In this study, in vitro functional characteristics of PCT platelets were compared to control platelets prepared from pooled buffy coats using the approved platelet-additive solution T-Sol((R)). Platelets in platelet PAS III additive solution without PCT were evaluated as well. PCT also included the use of a psoralen (S-59) reduction device (SRD). MATERIALS AND METHODS: Four types of platelet concentrates were compared: (1) platelet concentrate in plasma/T-Sol; (2) platelet concentrate in plasma/PAS III; (3) platelet concentrate in plasma/PAS III, PCT, 9 h SRD and (4) platelet concentrate in plasma/PAS III, PCT, 16 h SRD. PCT occurred on the day after whole-blood collection. In vitro assay parameters included: pH, pO(2), pCO(2), HCO(-)(3), platelet count, mean platelet volume, plasma glucose, plasma lactate, total ATP, expression of p-selectin, hypotonic shock response and electron microscopy. RESULTS: The results indicate that PCT is compatible with platelet concentrates prepared from pooled buffy coats for up to 7 days of storage. CONCLUSION: The PCT process resulted in acceptable in vitro platelet functional characteristics and is currently in clinical trials to evaluate the haemostatic efficacy of PCT platelets in thrombocytopenic patients requiring multiple platelet transfusions.     

Platelet Concentrates Stored at 22°C Need Oxygen The Significance of Plastics in Platelet Preservation

Platelet concentrates prepared by platelet apheresis were stored in plastic blood bags with different gas permeability properties. Inadequate oxygen supply gave an insufficient adenosine triphosphate (ATP) regeneration and a compensatory increase in glycolysis and lactic acid production, giving a rapidly falling pH. At pH below 6.0 the glycolysis was inhibited, oxygen consumption ceased, and ATP dropped towards depletion. Adequate oxygen supply kept the lactic acid production low with small pH changes only, and allowed a sufficient ATP regeneration. The release of alpha-granular platelet Factor 4 (PF4) was almost total at pH below 6.0, while at intact metabolic function there was a slow release of PF4. Platelet preservation is enhanced by the use of blood bags with adequate gas exchange properties. In our study one polyvinyl chloride plastic (PVC) bag gave poor results, while another PVC bag and a polyolefin bag showed intact metabolism for 5 days and a moderate release of PF4.     

Metabolic Status of Platelet Concentrates during Extended Storage: Improvement with Pharmacological Inhibitors and Reduced Surface-to-Volume Ratio

The depletion of plasma nutrients and buffering capacity may present a potential barrier to the long-term liquid storage of platelet concentrates (PC). We have found that PC prepared with reversible inhibitors of platelet activation added to the citrate anticoagulant and stored at a reduced surface-to-volume (S/V) ratio have a much slower rate of lactate build-up (p less than 0.01), slower consumption of glucose (p = 0.05), and more stable pH (p less than 0.01) than controls. By pO2 and pCO2 measurements, PC prepared with inhibitors showed evidence of continued respiration and responsiveness even after storage at 22 degrees C for 15 days. In addition, these PC released only 11% of the total cellular LDH during the storage period as compared to the release of 43-67% of the total LDH in control PC. Maximum benefit of the inhibitors was seen after reduction of the S/V ratio of the storage container, which was made possible by the reduced metabolic demands of platelets stored in the unactivated state. These data suggest that the fall in pH and loss of platelet integrity associated with the platelet storage lesion are correlated with a high metabolic rate which can be controlled by inhibiting the activation of platelets during preparation and storage. The use of these inhibitors and reduced bag surface area may make prolonged liquid storage of platelets feasible.     

Effect of Nitric Oxide Donor on Metabolism of Apheresis Platelets

The aim of this study is to investigate the effects of a nitric oxide (NO) donor S-nitrosoglutathione (GSNO) on the metabolism and improvement of preservation quality in apheresis platelets. A GSNO solution with a certain concentration was added into fresh apheresis platelets, and the parameters associated with platelet morphology, metabolism and function were temporally monitored for 7 days. The results showed that the NO level in GSNO group were remarkably higher than those in the control group during the whole storage stage. No significant morphology or function difference was observed between the control and GSNO groups such as Platelet count, platelet distribution width, mean platelet volume and mitochondrial metabolic activity. But in metabolism there are something differences from morphology data: pCO₂, pO₂, cHCO₃ ^? were also found to have no clear difference between the control and GSNO groups; the lactic acid content, sugar consumption and Lactate dehydrogenase activity in the GSNO group were lower than that in the control group at some time point; and pH values in the GSNO group were higher than the control group. Our study discovered that the NO donor GSNO can reduce the metabolism and maintain the cellular characteristics of platelets in vitro during the platelet storage period.     

Crotalocytin: characterization of the timber rattlesnake platelet activating protein

Crotalocytin, a platelet activating protein from timber rattlesnake venom, was studied to characterize its nature and to investigate its action on platelets. It exhibited proteolytic activity on the substrate azocoll and amidolytic activity on several peptide p-nitroanilides. The platelet activating and amidolytic activity of Crotalocytin was inhibited by diisopropylfluorophosphate. In addition, phenylmethylsulfonyl fluoride inhibited Crotalocytin's ability to stimulate platelets. Active site titration with p-nitrophenyl guanidobenzoate indicated that 52% of Crotalocytin's molecules were active and that the enzyme could also hydrolyze the titrant. These studies showed that Crotalocytin is a serine protease. Like thrombin and collagen, Crotalocytin induced simultaneous platelet aggregation and adenosine triphosphate (ATP) secretion. EDTA and prostaglandin E (PGE1) blocked Crotalocytin's ability to activate platelets; hirudin and antithrombin III did not. Crotalocytin stimulated the secretion of serotonin from dense granules and low affinity platelet factor 4 and fibrinogen from alpha-granules. Crotalocytin did not cause platelet lactic dehydrogenase loss or agglutinate formalin-fixed platelets, but it did aggregate chymotrypsin-treated platelets. Studies with antimycin A and 2 deoxy- D-glucose showed that Crotalocytin-induced platelet secretion was dependent on metabolic energy. Furthermore, Crotalocytin's induction of platelet secretion was prevented by eliminating exogenous ADP and blocking activation of the arachidonate pathway. Timber rattlesnake venom contains a serine protease that is unique, potent platelet activator.     

In vitro evaluation of Haemonetics MCS+ apheresis platelet concentrates treated with photochemical pathogen inactivation following plasma volume reduction using the INTERCEPT Preparation Set

Pathogen inactivation using the INTERCEPT Blood System requires platelet resuspension in InterSol and reduced plasma. Platelets in plasma collected on the Haemonetics MCS+ were processed on the INTERCEPT Preparation Set for plasma volume reduction and addition of InterSol. The use of the Preparation Set resulted in a mean platelet loss of 5.6 +/- 3.4%. Subsequent photochemical treatment (PCT) with amotosalen and ultraviolet A light, and 7 days of storage, resulted in acceptable changes for platelet swirling, lactate, lactate dehydrogenase (LDH), platelet factor-4 (PF4), p-selectin, glycoprotein V (GpV), pO2, pCO2, tumour necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8). All platelet units processed with the Preparation Set and PCT met European requirements for leucoreduction and pH values.     

Antioxidants in the treatment of diabetes

Diabetes is a chronic metabolic disorder that continues to present as a major health problem worldwide. It is characterized by absolute or relative deficiencies in insulin secretion and/or insulin action and is associated with chronic hyperglycemia and disturbances of carbohydrate, lipid, and protein metabolism. Many studies suggest a central role for oxidative stress in the pathogenesis of this multi-faceted metabolic disorder. This has prompted investigations in the use of antioxidants as a complementary therapeutic approach. In this review we briefly summarize oxidative mechanisms implicated in diabetic complications and then focus on the findings resulting from human clinical trials where antioxidants were studied as an adjuvant to standard diabetes treatment during the last ten years. A literature search using PubMed (last ten years) was performed using the following terms: vitamin E, vitamin C, coenzyme Q10, alpha lipoic acid, L-carnitine, ruboxistaurin or LY 333531 and diabetes. This search was limited to human clinical trials. We concluded there is not any established benefit for antioxidants use in the management of diabetic complications. Therefore, routine vitamin or mineral supplementation is not generally recommended.     

Extended storage of platelets in an artificial medium with the platelet activation inhibitors prostaglandin E1 and theophylline

The addition of platelet activation inhibitors to the anticoagulant and the replacement of plasma with a fortified electrolyte medium have been shown separately in previous work to improve the storage of platelets during a 2-week period. In the present study, we have combined these strategies to investigate whether a synergistic improvement could be obtained. A total of 85 concentrates was studied with 300 nM prostaglandin E1 (PGE1) and 1.9 mM theophylline added to the whole blood, platelet-rich plasma (PRP), and/or the storage medium during the preparation of platelet concentrates. In vitro markers of platelet aggregation, respiration, and cell integrity were measured over a 20-day storage period and evaluated in an analysis of variance. We found that a single-step addition of PGE1 and theophylline to the PRP prior to centrifugation was not sufficient in terms of preventing a rapid fall in pH, rise in pO2, fall in pCO2, loss of hypotonic shock response, and loss of aggregation response, compared to the addition of the inhibitors to the storage medium used to resuspend the platelet pellet. Factorial analysis showed that a reduction in the surface-to-volume ratio of the storage container further improved the maintenance of platelet respiration and, for three in vitro markers (hypotonic shock response, released lactic dehydrogenase, and surface glycoprotein Ib levels) displayed an interactive effect with the inhibitors. The addition of protease inhibitors to the formulation of PGE1 and theophylline showed further improvement in several markers. These findings demonstrate the possibility of preserving platelets for 15-20 days with the synergistic effects of activation inhibitors and an electrolyte storage medium fortified with citrate, buffers, and dextrose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in Microsomal Phospholipases and Arachidonic Acid in Experimental Alcoholic Liver Injury: Relationship to Cytochrome P-450 2E1 Induction and Conjugated Diene Formation

We evaluated the role of changes in microsomal phospholipases (A and C) and arachidonic acid in the intragastric rat feeding model. The experimental animals (male Wistar rats), divided into 4–5 rats/group, were fed the following diets: corn oil and ethanol and corn oil plus dextrose. One set of groups was killed after 2 weeks of feeding, and the second set was killed after 1 month. For each animal, microsomal analysis of cytochrome P-450 2E1 (CYP 2E1) and fatty acids was done. Fourteen animals had analyses of phospholipase C (PLC) and phospholipase A (PLA), and 10 animals had measurements of conjugated dienes. A significant correlation was obtained between the level of CYP 2E1 and the decrease in arachidonic acid (AA) from baseline levels ( r = 0.69, p < 0.01). The decrease in AA also correlated with the increase in conjugated dienes ( r = 0.70, p < 0.05). PLA and PLC activities were both significantly increased in the corn oil and ethanol groups. The activity of PLC correlated with the decline in AA ( r = 0.69, p < 0.01). The correlations noted between the decrease in microsomal AA and CYP 2E1 induction and conjugated diene formation suggest that these processes may be interlinked especially in regard to generation of lipid peroxides that may play a role in alcoholic liver injury.