Search PubMed⌕ Search

Biomedical subjects

G Ragno

Publications and source records attributed to G Ragno.

At least 19 recordsLinked to original sources
PubMed2006

Effects of centrifugal and roller pumps on survival of autologous red cells in cardiopulmonary bypass surgery.

BACKGROUND: Either a roller pump or a centrifugal pump can be used in the extracorporeal circuit during surgery with cardiopulmonary bypass. In this study, we assessed the effect of these two pumps on the 24-h post-transfusion survival values of autologous red blood cells (RBC). STUDY DESIGN AND METHODS: Fourteen male patients subjected to extracorporeal bypass procedures were studied. In seven patients, the autologous red cells were collected following the cardiopulmonary bypass procedure using the roller pump, and in seven patients, autologous red cells were collected following the cardiopulmonary procedure using the centrifugal pump. The 24-h post-transfusion survival values of the autologous RBC were measured using the 51 disodium chromate/99m technetium double isotope procedure. The effects of the extracorporeal bypass procedures using the roller pump and the centrifugal pump were also assessed by the measurements of hematocrit, platelet count, plasma hemoglobin, and serum lactate dehydrogenase levels. RESULTS: The 51 disodium chromate 24-h post-transfusion survival values of the autologous RBC were similar whether the roller pump or the centrifugal pump was used in the extracorporeal circulation, as were the hematocrit, platelet count, plasma hemoglobin and serum lactate dehydrogenase levels. CONCLUSION: The 24-h post-transfusion survival values of autologous RBC, measured by the 51 disodium chromate/99m technetium double isotope procedure, were not significantly different, whether the roller pump or the centrifugal pump was used in the extracorporeal circuit using membrane oxygenators during cardiopulmonary surgical procedures.

Adult↗
PubMed2005

Accelerated photostability study of tretinoin and isotretinoin in liposome formulations.

The photodegradation of retinoic acids, tretinoin and isotretinoin, in ethanol and liposomes was studied. The light irradiation was performed according to the conditions suggested by the ICH Guideline for photostability testing by using a Xenon lamp within a wavelength range of 300-800 nm. The photodegradation process was monitored by UV spectrophotometry. In ethanol solution, tretinoin and isotretinoin undergo complete isomerization just within a few seconds of light exposure to give 13-cis and 9-cis isomers, respectively. The 13-cis isomer from tretinoin undergoes in turn a slow isomerization to the same 9-cis isomer. Both retinoic acids incorporated in liposome complexes showed an increased stability in comparison to the ethanol solutions. In particular for tretinoin, a residual concentration of 60% was still present after a light irradiance of 3470 kJ/m(2), by means of a 250 W/m(2) light power for 240 min, versus a residual value of just 8% measured at the same time in ethanol solution. Moreover, the isomerization rate in liposomes resulted reduced for isotretinoin and practically irrelevant for tretinoin. The degradation rate was found to be dependent on the drug concentration. The better stability of the tretinoin in liposome complex was supposed to be related to its higher incorporation value due to the linear structure of the molecule.

Chemistry, Pharmaceutical↗
PubMed2005

Correlation between in vitro aggregation and thromboxane A2 production in fresh, liquid-preserved, and cryopreserved human platelets: effect of agonists, pH, and plasma and saline resuspension.

BACKGROUND: Some of the tests used to assess the quality of fresh and preserved platelets (PLTs) include PLT number, PLT morphology, pH of the PLT medium, PLT response to hypotonic stress, and PLT aggregation to agonists. This study was performed to assess the function of fresh and preserved PLTs by their response to aggregation and their production of thromboxane A2 after in vitro stimulation with agonists. STUDY DESIGN AND METHODS: PLTs isolated by apheresis procedures were stored at 22 degrees C for as long as 5 days and then frozen with 6 percent dimethyl sulfoxide, stored at -80 degrees C, thawed, washed, and resuspended in medium. The effects of agonists and the pH and composition of the medium on PLT aggregation and PLT production of thromboxane A2 after stimulation were measured. RESULTS: The agonists and the pH and composition of the medium affected both the aggregation response and the production of thromboxane A2 by the fresh and preserved PLTs. PLT aggregation response to arachidonic acid (AA) and adenosine diphosphate (ADP) was significantly lower in the cryopreserved PLTs than in the fresh and preserved PLTs. After stimulation with AA and ADP, the cryopreserved PLTs produced more thromboxane than did the fresh and liquid-preserved PLTs. CONCLUSIONS: The agonists and the pH and composition of the medium affected the response to aggregate and produce thromboxane in vitro in both the fresh and the liquid-preserved PLTs. PLT thromboxane A2 production may be a better in vitro test than PLT aggregation to assess PLT function in vivo.

Adenosine Diphosphate↗
PubMed2005

Survival of baboon biotin-X-N-hydroxysuccinimide and (111)In-oxine-labelled autologous fresh and lyophilized reconstituted platelets.

BACKGROUND AND OBJECTIVES: In accordance with Food and Drug Administration (FDA) regulations, platelets can be stored in the liquid state at 22 degrees C for only 5 days. Platelets frozen with 6% dimethylsulphoxide (DMSO) can be stored at -80 degrees C for 2 years, and platelets frozen with 5% DMSO can be stored at -150 degrees C for 3 years. Studies are being conducted to determine the effects of lyophilization of platelets. In the present study, we assessed the survival of autologous lyophilized-reconstituted platelets in the baboon. MATERIALS AND METHODS: We studied fresh baboon platelets and baboon platelets that had been treated with paraformaldehyde, frozen, lyophilized, thawed and reconstituted. Aliquots of these platelets were labelled with (111)In-oxine or biotin-X-N-hydroxysuccinimide (biotin-X-NHS) before autotransfusion, and measurements were made of the in vivo recovery and lifespan. We also evaluated the response of fresh and lyophilized platelets to in vitro agonists by measuring the level of platelet surface markers and heterotypic aggregates in the peripheral blood following the autotransfusions. RESULTS: The (111)In-oxine- or biotin-X-NHS-labelled lyophilized, reconstituted platelets exhibited survival times of less than 15 min. These platelets did not respond to stimulation with agonists to decrease platelet GPIb and increase platelet P-selectin and platelet GPIIb-IIIa levels 1 min post-transfusion and they accumulated more procoagulant factor V than did the fresh platelets. CONCLUSIONS: Lyophilized reconstituted baboon platelets labelled with (111)In-oxine or biotin-X-NHS before autotransfusion exhibited an in vivo circulation time of less than 15 min. Further study of the lyophilized, reconstituted platelets is required to evaluate their haemostatic function.

Animals↗
PubMed2004

In vitro testing of fresh and lyophilized reconstituted human and baboon platelets.

BACKGROUND: Studies have been performed on human fresh, liquid-preserved, and cryopreserved platelets (PLTs) to assess PLT-adhesive surface receptors, PLT membrane procoagulant activity, PLT aggregation, and thromboxane production. Lyophilization has been developed as a method to preserve PLTs. This study was performed to evaluate these measurements on human and baboon fresh and lyophilized reconstituted PLTs. STUDY DESIGN AND METHODS: In both human and baboon fresh and lyophilized PLTs, aggregation response and PLT production of thromboxane A2 were measured after stimulation, and PLT surface markers P-selectin, glycoprotein (GP) Ib, GPIIb-IIIa, and factor (F) V were measured before and after stimulation. RESULTS: Fresh PLTs responded to the dual agonists arachidonic acid and adenosine diphosphate (ADP) to aggregate and produce thromboxane A2, and in both the PLT surface markers P-selectin and GPIIb-IIIa increased and GPIb decreased after stimulation. Neither human nor baboon lyophilized reconstituted PLTs aggregated to dual agonists, and neither produced thromboxane A2, increased PLT surface markers P-selectin or GPIIb-IIIa, or decreased PLT GPIb after stimulation. Nevertheless, after recalcification the lyophilized reconstituted PLTs accumulated FV to a significantly greater degree than fresh PLTs. CONCLUSIONS: Lyophilized reconstituted PLTs exhibited modification of the PLT membrane that interfered with aggregation and thromboxane production, prevented increases in PLT P-selectin and GPIIb-IIIa and decreases in GPIb after stimulation, and increased FV accumulation after recalcification. The in vitro data suggest that lyophilized PLTs may have reduced in vivo survival. In vivo studies are needed to determine the survival and function of lyophilized PLTs.

Animals↗
PubMed2003

Design and monitoring of photostability systems for amlodipine dosage forms.

Photostability of amlodipine (AML) has been monitored in several pharmaceutical inclusion systems characterized by plurimolecular aggregation of the drug and excipients with high molecular weight. Several formulations including cyclodextrins, liposomes and microspheres have been prepared and characterized. The photodegradation process has been monitored according to the conditions suggested by the ICH Guideline for photostability testing, by using a light cabinet equipped with a Xenon lamp and monitored by spectrophotometry. The formulations herein tested have been found to be able to considerably increase drug stability, when compared with usual pharmaceutical forms. The residual concentration detected in the inclusion complexes with cyclodextrins and liposomes was 90 and 77%, respectively, while a very good value of 97% was found for microspheres, after a radiant exposure of 11,340 kJm(-2).

Amlodipine↗
PubMed2003

Restoration of red blood cell volume following 2-unit red blood cell apheresis.

BACKGROUND AND OBJECTIVES: Blood donors who weigh at least 130 lbs (59 kg) and have a haematocrit of at least 40 V per cent can donate 2 units of blood, from which a 360-ml volume of red blood cells (RBC) can be isolated. This study was carried out in seven healthy male blood donors to assess the restoration of the RBC volume 1 month following a 2-unit RBC apheresis procedure. MATERIALS AND METHODS: RBC volumes were measured prior to donation and 4 weeks after the 2-unit RBC apheresis procedure without oral iron supplementation. RESULTS: Four weeks after the removal of 2 units of RBC from the male donors not supplemented with oral iron, the RBC volume was restored to 92% of the precollection value. The 360-ml volume of RBC collected represented 12-19% of the donor's original RBC volume. CONCLUSIONS: Male donors can safely donate 2 units of RBC and will restore a mean of 92% of their RBC volume within 1 month without iron supplementation.

Adult↗
PubMed2002

Circulation and distribution of autotransfused fresh, liquid-preserved and cryopreserved baboon platelets.

BACKGROUND AND OBJECTIVES: Studies were carried out in five healthy male baboons to determine the 111indium oxine (111In-oxine) survival of autologous fresh, liquid-preserved and cryopreserved platelets. Simultaneous organ-distribution studies were performed to determine the percentage uptake of platelets by the spleen and/or liver. MATERIALS AND METHODS: Each of five baboons was transfused, on three different occasions, with autologous fresh platelets stored at 22 degrees C for 18 h, liquid-preserved platelets stored at 22 degrees C for 5 days and washed previously frozen platelets, labelled with 111In-oxine. RESULTS: In vivo recovery at 2 h was 81% for the fresh platelets, 54% for the previously frozen platelets and 44% for the 5-day-old liquid-preserved platelets. The weighted mean life span was 5.4 days for fresh platelets, 4.2 days for previously frozen platelets and 2 days for liquid preserved platelets. Increased radioactivity was detected over the liver 2 h after transfusion for both the previously frozen and liquid-preserved platelets. CONCLUSIONS: Cryopreserved platelets and liquid-preserved platelets stored at 22 degrees C for 5 days had reduced survival 2 h post-transfusion and reduced life span values compared to fresh platelets. In addition, the finding of increased radioactivity over the liver in the baboons that received cryopreserved and liquid-preserved platelets suggested that the liver was the site for removal of the non-viable platelets.

Animals↗
PubMed2001

Survival, function, and hemolysis of shed red blood cells processed as nonwashed blood and washed red blood cells.

BACKGROUND: Shed nonwashed blood and shed washed red blood cells (RBC) are being used as alternatives to allogeneic liquid-preserved RBC for patients during thoracic and cardiovascular surgical procedures. METHODS: Mongrel dogs were bled a volume of blood into the abdominal cavity and the shed blood was reinfused as nonwashed blood or washed RBC. The 51Cr RBC volumes were measured before, immediately after, and 24 hours after the exchange transfusion to assess the recovery of the shed RBC and the 24-hour posttransfusion survival. Compatible dogs were given allogeneic transfusions of 51Cr-labeled nonwashed blood and washed RBC, and 24-hour posttransfusion survival and half-life were measured. RESULTS: Immediately after the 100% exchange transfusion, the recovery value was 62% for the nonwashed shed blood and 82% for the washed RBC. Both the nonwashed blood and the washed RBC had 24-hour posttransfusion survival values of 90% and normal oxygen transport function after the exchange transfusion. Compatible allogeneic 51Cr-labeled nonwashed blood and washed RBC had normal 24-hour posttranfusion survival and 51Cr half-life values. CONCLUSIONS: The survival, function, and hemolysis of shed nonwashed blood and shed washed RBC were similar to fresh blood in the dog that underwent a 100% exchange transfusion.

Animals↗
PubMed2001

24-hour 51Cr post-transfusion survival, 51Cr life span and haemolysis of red blood cells stored at 4 degrees C for 56 days in AS-3.

BACKGROUND AND OBJECTIVES: Red blood cells (RBC) were collected either by a manual method using a 16-gauge needle or by an apheresis procedure using an 18-gauge needle, and were stored at 4 degrees C in a solution of CP2D (anticoagulant)/AS-3 (Nutricel) for 56 days. The purpose was to compare the outcome of the autotransfused red cells collected by both techniques. MATERIALS AND METHODS: Five healthy male volunteers were studied on two occasions. RESULTS: The autotransfusions of the manual and apheresed RBC resulted in a mean 24-h post-transfusion survival of 71%, a normal mean 51Cr RBC life span, a 2,3 DPG level that was less than 10% of normal, and 0.6% haemolysis. CONCLUSIONS: Whether collected manually or by apheresis, the outcomes were similar for RBC stored at 4 degrees C for 56 days in CP2D/AS-3.

2,3-Diphosphoglycerate↗
PubMed2001

Autologous platelet-rich plasma isolated using the Haemonetics Cell Saver 5 and Haemonetics MCS+ for the preparation of platelet gel.

BACKGROUND AND OBJECTIVES: We compared three methods of isolating platelet-rich plasma (PRP) using the Haemonetics Cell Saver 5 and one method of isolating PRP by plateletpheresis using the Haemonetics MCS+. PRP contains both platelets and fibrinogen, which are used in the preparation of haemostatic agents. MATERIALS AND METHODS: When the Haemonetics Cell Saver 5 was used, 500 ml of blood from each of 30 normal volunteer donors was collected into 70 ml of citrate-phosphate-dextrose (CPD) anticoagulant. In a further 14 normal volunteers, the Haemonetics MCS+ was used to isolate PRP by plateletpheresis using an acid citrate dextrose (ACD) to blood ratio of 1 : 9. In a separate study, CPD-anticoagulated whole blood from another 30 volunteers was used for measurement of fibrinogen levels in the plasma and cryoprecipitate. RESULTS: A larger volume of PRP can be collected using the Haemonetics Cell Saver 5 than by using the Haemonetics MCS+. The platelet concentration and the total number of platelets were higher in the PRP isolated using the Haemonetics MCS+ than in the PRP isolated by the three methods used with the Haemonetics Cell Saver 5, with differences in platelet concentration and PRP volume among the four methods. The mean fibrinogen level in the plasma was 253 mg % +/- 47 (SD) and in the cryoprecipitate was 1085 mg % +/- 304 (SD). CONCLUSIONS: The most appropriate method of PRP isolation for preparation of platelet gel is dependent upon the specific surgical procedure to be undertaken and the patient's needs.

Blood Transfusion, Autologous↗
PubMed2001

In vitro and in vivo measurements of human RBCs frozen with glycerol and subjected to various storage temperatures before deglycerolization and storage at 4 degrees C for 3 days.

BACKGROUND: This study was designed to assess the effects of changes in storage temperature of frozen RBCs such as might occur during a malfunction of the -80 degrees C mechanical freezer or during shipment. STUDY DESIGN AND METHODS: Fifteen participants donated blood for autologous transfusion of RBCs; all RBCs were frozen with 40-percent (wt/vol) glycerol. Five subjects received RBCs that were stored at -80 degrees C alone before transfusion. Five subjects received RBCs that were stored initially at -80 degrees C, then at -40 degrees C for 4 weeks, and finally at -80 degrees C before transfusion. Five subjects received RBCs that were stored at -80 degrees C, then at -20 degrees C for 2 weeks, and finally at -80 degrees C before transfusion. After deglycerolization, the RBCs were stored at 4 degrees C in a sodium chloride-glucose solution for 3 days before transfusion. RESULTS: No significant differences were observed in freeze-thaw recovery, freeze-thaw-wash recovery, 24-hour posttransfusion survival, index of therapeutic effectiveness, or RBC ATP levels. Greater hemolysis and reduced RBC K+ levels were observed in the units stored at -80 degrees C/-40 degrees C/-80 degrees C and in those stored at -80 degrees C/ -20 degrees C/-80 degrees C compared with the units stored at -80 degrees C alone, but these differences did not affect the 24-hour posttransfusion survival. CONCLUSIONS: The results of this study indicated that RBCs frozen with 40-percent (wt/vol) glycerol can be stored at -40 degrees C for 4 weeks or at -20 degrees C for 2 weeks between periods of frozen storage at -80 degrees C with satisfactory results.

Adenosine Triphosphate↗
PubMed2001

In vitro and in vivo measurements of gamma-radiated, frozen, glycerolized RBCs.

BACKGROUND: Transfusion-associated GVHD results from the presence of viable lymphocytes in transfused allogeneic blood components. Viable immunocompetent lymphocytes have been detected in RBCs that were frozen with glycerol and washed before transfusion. STUDY DESIGN AND METHODS: The study reported here assessed the effect of irradiation on human RBCs frozen with 40-percent (wt/vol) glycerol and stored at -80 degrees C. In vitro and in vivo testing was done on human RBCs that were frozen with 40-percent (wt/vol) glycerol at -80 degrees C, with some units exposed to 2500 cGy of gamma radiation and others not irradiated, and that, after thawing and washing, were stored in a sodium chloride-glucose solution at 4 degrees C for 3 days before autologous transfusion. RESULTS: The glycerol-frozen RBCs treated with 2500 cGy before deglycerolization had a mean freeze-thaw-wash recovery of 87 percent and a mean 24-hour posttransfusion survival of 86 percent after storage for 3 days at 4 degrees C in a 0.9-percent NaCl and 0.2-percent glucose solution. For the nonirradiated units, the mean freeze-thaw-wash recovery was 85 percent and the mean 24-hour posttransfusion survival was 83 percent. CONCLUSION: These data show similar, acceptable results for RBCs frozen with 40-percent (wt/vol) glycerol at -80 degrees C and treated in the frozen state with 2500 cGy of gamma radiation and for RBCs that were not irradiated, all of which were washed and then stored in a sodium chloride-glucose solution for 3 days before autologous transfusion.

Cryopreservation↗
PubMed2001

In vivo survival of apheresis RBCs, frozen with 40-percent (wt/vol) glycerol, deglycerolized in the ACP 215, and stored at 4 degrees C in AS-3 for up to 21 days.

BACKGROUND: The FDA has approved the storage of frozen RBCs at -80 degrees C for 10 years and the postwash storage at 4 degrees C for no more than 24 hours. The 4 degrees C postwash storage period is limited to 24 hours, because the current deglycerolization systems are functionally open systems. STUDY DESIGN AND METHODS: Two units of RBCs were collected from each of 13 healthy male volunteers. The RBCs were collected in CP2D by the FDA-approved protocol for an automated apheresis device (MCS, LN8150, Haemonetics) and were stored at 4 degrees C in AS-3 for 6 days. Using a single disposable glycerolization set in an automated, functionally closed system (ACP 215, Haemonetics) each unit was transferred to a 1000-mL PVC plastic bag and glycerolized to a concentration of 40-percent (wt/vol) glycerol and frozen at -80 degrees C. A single disposable deglycerolization set in the ACP 215 was used to deglycerolize the 2 units from the same donor. The deglycerolized RBCs were stored at 4 degrees C in AS-3 for as long as 21 days. RESULTS: The mean +/- SD freeze-thaw-wash recovery value was 89.4 +/- 3 percent. The residual hemolysis in the RBCs stored at 4 degrees C in AS-3 for 21 days after deglycerolization was 0.9 +/- 0.2 percent, and the units were negative for both aerobic and anaerobic bacteria. The mean Nageotte WBC count was 9 x 10(6) per unit. When the deglycerolized RBCs were given as an autologous transfusion after storage at 4 degrees C in AS-3 for the 7- to 18-day period, the mean +/- SD 24-hour posttransfusion survival was 77 +/- 7 percent, and the index of therapeutic effectiveness was 69 +/- 8 percent. CONCLUSION: Two units of human RBCs collected from a single donor by apheresis in the MCS using an LN8150 set can be glycerolized sequentially with a single disposable set and deglycerolized sequentially with another single disposable set in the ACP 215. The previously frozen RBCs stored in AS-3 for 7 to 18 days at 4 degrees C had acceptable hemolysis and an acceptable mean 24-hour posttransfusion survival value and index of therapeutic effectiveness.

Adenine↗
PubMed2001

A multicenter study of in vitro and in vivo values in human RBCs frozen with 40-percent (wt/vol) glycerol and stored after deglycerolization for 15 days at 4 degrees C in AS-3: assessment of RBC processing in the ACP 215.

BACKGROUND: The FDA has approved the storage of frozen RBCs at -80 degrees C for 10 years. After deglycerolization, the RBCs can be stored at 4 degrees C for no more than 24 hours, because open systems are currently being used. Five laboratories have been evaluating an automated, functionally closed system (ACP 215, Haemonetics) for both the glycerolization and deglycerolization processes. STUDY DESIGN AND METHODS: Studies were performed at three military sites and two civilian sites. Each site performed in vitro testing of 20 units of RBCs. In addition, one military site and two civilian sites conducted autologous transfusion studies on ten units of previously frozen, deglycerolized RBCs that had been stored at 4 degrees C in AS-3 for 15 days. At one of the civilian sites, 10 volunteers received autologous transfusions on two occasions in a randomized manner, once with previously frozen RBCs that had been stored at 4 degrees C in AS-3 for 15 days after deglycerolization and once with liquid-preserved RBCs that had been stored at 4 degrees C in AS-1 for 42 days. RESULTS: The mean +/- SD in vitro freeze-thaw-wash recovery value was 87 +/- 5 percent; the mean +/- SD supernatant osmolality on the day of deglycerolization was 297 +/- 5 mOsm per kg of H(2)O, and the mean +/- SD percentage of hemolysis after storage at 4 degrees C in AS-3 for 15 days was 0.60 +/- 0.2 percent. The paired data from the study of 10 persons at the civilian site showed a mean +/- SD 24-hour posttransfusion survival of 76 +/- 6 percent for RBCs that had been stored at 4 degrees C for 15 days after deglycerolization and 72 +/- 5 percent for RBCs stored at 4 degrees C in AS-1 for 42 days. At the three sites at which 24-hour posttransfusion survival values were measured by three double-label procedures, a mean +/- SD 24-hour posttransfusion survival of 77 +/- 9 percent was observed for 36 autologous transfusions to 12 females and 24 males of previously frozen RBCs that had been stored at 4 degrees C in AS-3 for 15 days after deglycerolization. CONCLUSION: The multicenter study showed the acceptable quality of RBCs that were glycerolized and deglycerolized in the automated ACP 215 instrument and stored in AS-3 at 4 degrees C for 15 days.

Blood Preservation↗
PubMed2001

Anemia-induced increase in the bleeding time: implications for treatment of nonsurgical blood loss.

BACKGROUND: Preoperative bleeding time (BT) does not correlate with postoperative bleeding in patients subjected to surgical procedures. A significant positive correlation has been reported between the BT 2 hours after cardiopulmonary bypass surgery and the nonsurgical blood loss during the first 4 hours after bypass surgery. This study was done to investigate the effect of Hct and platelet count on the BT measurement in normal, healthy men and women. STUDY DESIGN AND METHODS: To assess the relative effect of RBCs and platelets on the BT, 22 healthy male and 7 healthy female volunteers were subjected to the removal of 2 units of RBCs (360 mL), followed by the return of the platelet-rich plasma (PRP) from both units and the infusion of 1000 mL of 0.9-percent NaCl. Four of the men and all seven women received their RBCs 1 hour after their removal. Shed blood levels of thromboxane B(2) (TXB(2)), 6-keto prostaglandin F(1 alpha), and peripheral venous Hct were measured. BTs were measured in 15 men and 13 women before and after a plateletpheresis procedure to collect 3.6 x 10(11) platelets per unit. RESULTS: The 2-unit RBC apheresis procedure produced a 60-percent increase in the BT associated with a 15-percent reduction in the peripheral venous Hct and a 9-percent reduction in the platelet count. The plateletpheresis procedure produced a 32-percent decrease in the platelet count, no change in peripheral venous Hct, and no change in the BT. After the removal of 2 units of RBCs, the shed blood TXB(2) level decreased significantly. Reinfusion of 2 units of RBCs restored the BT and restored the TXB(2) level to the baseline levels. CONCLUSION: The acute reduction in Hct produced a reversible platelet dysfunction manifested by an increase in BT and a decrease in the shed blood TXB(2) level at the template BT site. Return of the RBCs restored both the BT and the shed blood TXB(2) level to normal. The platelet dysfunction observed with the reduction in Hct was due in part to a reduction in shed blood TXB(2) and other, unknown mechanisms.

Adult↗