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Biomedical subjects

G Ragno

Publications and source records attributed to G Ragno.

At least 19 recordsLinked to original sources
PubMed1999

Effect of 24-hour whole-blood storage on plasma clotting factors.

BACKGROUND: The current requirements for the preparation of fresh-frozen plasma within 8 hours of whole-blood collection were designed to maintain clotting factor activities. These requirements, however, limit the production of fresh-frozen plasma in a large blood center. There are few data on the effect of the extension of CPD whole-blood storage to 24 hours on clotting factor activity. STUDY DESIGN AND METHODS: A 500-mL unit of whole blood was collected from 10 volunteer donors. At 1 hour after collection, a plasma sample was separated by centrifugation, and each unit was equally divided into 2 half-units, with 1 half-unit stored at 4 degrees C (range, 1-6 degrees C) and 1 half-unit stored at 22 degrees C (range, 20-24 degrees C) for 8 hours after collection. Each half-unit was then placed at 4 degrees C for further storage for 16 hours. At 8 and 24 hours after collection, plasma samples were separated from each half-unit. All plasma samples were frozen at -18 degrees C. Factors V, VII, VIII, and X; fibrinogen; antithrombin III; protein C; and protein S were measured. RESULTS: No significant changes were noted in factors V, VII, and X; fibrinogen; antithrombin III; protein C; and protein S over the 24-hour storage period. Factor VIII in both half-units was significantly reduced, by 13 percent, from the baseline sample as compared to the level in the 8-hour storage sample (p<0.05). Factor VIII was further reduced by 15 to 20 percent after the 24-hour storage period (p<0.05). CONCLUSION: The coagulation factor activity for all factors measured, with the exception of factor VIII, showed no significant change over the 24-hour storage period. Factor VIII was significantly decreased by 13 percent in 8-hour storage and by an additional 15 to 20 percent in 24-hour storage. For clinical situations not requiring the replacement of factor VIII only, 24-hour frozen plasma has properties comparable to those of fresh-frozen plasma.

Analysis of Variance↗
PubMed1999

Platelet surface p-selectin, platelet-granulocyte heterotypic aggregates, and plasma-soluble p-selectin during plateletpheresis.

BACKGROUND: Plateletpheresis components have been shown to contain p-selectin-positive platelets after collection and storage. P-selectin mediates binding of activated platelets to granulocytes and monocytes. This study was undertaken to assess platelet activation, granulocyte activation, platelet-granulocyte heterotypic aggregate formation, and the plasma-soluble p-selectin level during plateletpheresis performed on a particular instrument (MCS+, Haemonetics). STUDY DESIGN AND METHODS: Flow cytometry was used to assay platelet surface p-selectin, granulocyte iC3b receptor, and platelet-granulocyte aggregates in the platelet component, residual blood in the disposable polycarbonate bowl of the MCS+, and in the donor blood with and without the addition of in vitro agonists before, during, and after plateletpheresis. The plasma-soluble p-selectin levels in the platelet component, disposable bowl, and donor venous blood were measured by an enzyme-linked immunosorbent assay. RESULTS: Levels of p-selectin-positive platelets, activated granulocytes, and platelet-granulocyte aggregates were greater in the disposable bowl than in the preapheresis donor blood. Levels of p-selectin-positive platelets, activated granulocytes, and platelet-granulocyte aggregates in the postapheresis donor blood were similar to those in the preapheresis donor blood. The platelet components contained no activated granulocytes or detectable platelet-granulocyte heterotypic aggregates, and only about 10-percent activated platelets. The plasma-soluble p-selectin level in the platelet component was significantly greater than that in the preapheresis donor blood, the residual blood in the disposable bowl, or the postapheresis donor blood. CONCLUSIONS: Measurements of platelet surface p-selectin, platelet-granulocyte heterotypic aggregates, and plasma-soluble p-selectin can be used to detect platelet activation during plateletpheresis.

Antibodies, Heterophile↗
PubMed1999

Fresh, liquid-preserved, and cryopreserved platelets: adhesive surface receptors and membrane procoagulant activity.

BACKGROUND: A study in humans showed that the transfusion of previously frozen human platelets after cardiopulmonary bypass, despite decreased survival, resulted in better hemostatic function than that of liquid-preserved platelets stored at 22 degrees C for 3 to 4 days. STUDY DESIGN AND METHODS: In this study, fresh, 3- to 4-day-old liquid-preserved, and cryopreserved human platelets were studied by the use of monoclonal antibodies directed against p-selectin, glycoprotein (GP)Ib, activated GPIIb/IIIa, and coagulation factor V in a three-color flow cytometric method. RESULTS: The fresh and liquid-preserved platelets had normal surface levels of GPIb, while the cryopreserved platelets were composed of distinct subpopulations of GPIb-normal and GPIb-reduced platelets. On the basis of the binding of factor V, both subpopulations of cryopreserved platelets exhibited greater surface binding of factor V than did fresh and liquid-preserved platelets. Activated GPIIb/IIIa was elevated on GPIb-normal platelets, but not on GPIb-reduced platelets. Baboon platelets frozen by a procedure identical to that used to freeze human platelets also had GPIb-normal and GPIb-reduced subpopulations after the freezing-thawing-washing procedure. Autologous cryopreserved baboon platelets labeled with biotin-X-N-hydroxysuccinimide showed a rapid removal of GPIb-reduced platelets during the 5-minute postinfusion period, whereas GPIb-normal platelets had an in vivo recovery of 48 percent and a lifespan of slightly less than 6 days. CONCLUSIONS: Improved in vivo function of cryopreserved platelets may be related to the rapid hemostatic effect of the GPIb-reduced subpopulation secondary to increased binding of factor V and expression of p-selectin.

Animals↗
PubMed1997

Propofol assay in biological fluids in pregnant women.

A rapid, accurate and sensitive UV derivative method was described for measuring the Propofol concentration in some biological fluids. Furthermore two alternative procedures, a gaschromatographic and a colorimetric, were also defined, and the results of the three methods, when applied on blood samples spiked with known amounts of analyte, were compared. The samples were preliminary purified by a solid phase extraction on octadecyl C18 cartridge. The UV derivative method was applied to a pharmacokinetic study on pregnant women undergoing cesarean sections. After an induction dose administration of 2.5 mg kg-1, the maternal and umbilical vein blood were found to have comparable concentrations of propofol, with a mean half like of about 3.5 min; on the contrary no detectable levels of the drug were found in amniotic fluid. The drug recoveries > 98% and the response was linear over the range 0.05-40 micrograms ml-1.

Amniotic Fluid↗
PubMed1997

The effect of disinfection on viability and function of baboon red blood cells.

Methods that have been optimized for disinfection of red blood cells before transfusion must be evaluated for their effect on red blood cell viability and function in vitro and in vivo. This study evaluates (1) in vitro effects of Panavirocide treatment and benzoporphyrin (BPD) photosensitization on baboon and human red blood cell parameters and (2) in vivo effects of five disinfectant treatments on 24 h posttransfusion survival and cell lifetimes for baboon red blood cells. The in vitro studies showed that both disinfection methods resulted in a significant reduction in red blood cell potassium, suggesting that intracellular potassium is a sensitive measure of red cell injury during disinfection. The in vivo studies demonstrated significant reductions in the 24 h posttransfusion survival of baboon red blood cells and reductions in cell lifespan treated with a Panavirocide solution, BPD photosensitization and 15 mM nonactivated sodium chlorite. No effects were seen with 250 ppm formaldehyde, aluminum phthalocyanine photosensitization or activated sodium chlorite. These in vivo data showing effects of disinfection treatments support the use of baboons in studying disinfection procedures of autologous red blood cells before attempting studies in humans.

Animals↗
PubMed1996

Effect of heparin on fibrinolytic activity and platelet function in vivo.

Heparin, a polyanionic glycosaminoglycan, is used routinely before the induction of cardiopulmonary bypass. Earlier observations in our laboratory suggested that the postoperative bleeding that occurs, despite neutralization of heparin with protamine, is secondary to hypothermia and dilutional anemia during bypass. An additional, potential mechanism for excessive bleeding following cardiopulmonary bypass is that heparin activates the fibrinolytic system, which may, in turn, adversely affect hemostasis. To understand better the effects of heparin administration on the fibrinolytic system in vivo, we simulated the anticoagulant regimen of cardiopulmonary bypass by administering increasing doses of intravenous heparin to five adult baboons over 60 min. We measured fibrinolytic parameters serially following heparinization and demonstrated that heparin induces activation of the fibrinolytic system. We showed that the fibrinolytic system was activated in vivo as evidenced by an increase in plasmin activity and immunoreactive plasmin light chain, as well as an increase in immunoreactive fibrinogen fragment E in vitro. These results demonstrate that the fibrinolytic system is activated in vivo by the administration of heparin during cardiopulmonary bypass. These data suggest that, despite administration of a neutralizing agent such as protamine, heparin may contribute to postoperative bleeding complications following cardiopulmonary bypass surgery owing principally to its longer lived effects on the fibrinolytic system.

Animals↗
PubMed1996

Nasal spray bromocriptine: effects on serum prolactin in puerperal women.

BACKGROUND: The objective of this study was to investigate the effectiveness of a single nasal spray administration of 0.8 mg bromocriptine in reducing PRL serum levels. METHODS: Eighteen physiologically hyperprolactemic women in the early days of puerperium were randomized to receive nasal bromocriptine or placebo; PRL serum levels were measured by RIA at 45, 30 and 15 minutes before the administration and after the following times: 15, 30, 45, 60, 120, 180, 240, 300, and 480 minutes. RESULTS: After the administration of bromocriptine serum levels of PRL decreased rapidly; the reduction was statistically significant after 45 minutes. Four hours after the administration mean serum levels of PRL resulted in the normal range (< 20 micrograms/l); at the eighth hour the PRL levels were still normal. No one patient complained of any local or systemic side-effects. CONCLUSION: Nasal route seems to be an effective and probably safe administration route for bromocriptine.

Aerosols↗
PubMed1994

Safety and therapeutic effectiveness of reinfused shed blood after open heart surgery.

This prospective study was designed to determine whether use of nonwashed shed mediastinal blood exacerbated platelet and related hematologic dysfunctions after cardiopulmonary bypass, compared with the alternative use of autologous and homologous standard liquid preserved blood for volume support. Thirty-two patients undergoing cardiopulmonary bypass for open heart operations were randomized to receive either nonwashed shed mediastinal blood (group 1; n = 16) or liquid preserved packed red blood cells (group 2; n = 16) for transfusion therapy in the management of postoperative bleeding. Patient blood samples and bleeding times were obtained preoperatively, after cardiopulmonary bypass but before transfusions, 2 and 24 hours after transfusion, and on postoperative days 2, 3, and 7. Group 1 patients received an average of 710 +/- 90 mL (range, 300 to 1,700 mL) of nonwashed shed mediastinal blood containing significantly greater (p < 0.0001) amounts of fibrin degradation products and D-dimer protein. Of the hematologic, microaggregate, and plasma protein measurements performed, only the protein C level was significantly greater in group 1 (p < 0.05) after transfusion. Patient bleeding times were not significantly different between the groups at any of the time points, and the total postoperative blood loss was not different between the groups. There was a trend toward less need for homologous transfusion in group 1 (p < 0.1). This study documents the safety and ease of using nonwashed shed mediastinal blood as a primary blood volume support after an open heart operation.

Adult↗
PubMed1992

Effect of skin temperature on platelet function in patients undergoing extracorporeal bypass.

Thirty-seven patients undergoing cardiopulmonary bypass operations were studied to assess the effect of skin temperature on platelet function. Differences in skin temperature between the two arms were created during bypass, at the completion of bypass, and at 2 and 24 hours after the completion of bypass. In each of 37 patients the temperature of one arm was increased with a water-filled blanket set at 40 degrees C. In 11 of these patients the other arm was allowed to equilibrate with the environment, and in the other 26 patients the arm was cooled with ice. Except for the differences in local skin temperature between the two arms, all factors known to affect the patient's bleeding time were similar. Measurements were made of bleeding times and the levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha in shed blood obtained at the template bleeding time site. In the 33 patients not treated with aspirin, local hypothermia produced an increased bleeding time and a significant reduction in the thromboxane B2 level at the bleeding time site, but no reduction in 6-keto-prostaglandin F1 alpha level. Local rewarming produced a significant increase in the shed blood thromboxane B2 level. In the four patients treated with aspirin, local hypothermia produced no differences in bleeding times or shed blood levels of thromboxane B2 or 6-keto-prostaglandin F1 alpha. These data show the benefits of rewarming patients with hypothermia who have nonsurgical blood loss to restore to normal both core and peripheral temperatures before resorting to the transfusion of homologous blood products.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Hematologic changes during and after cardiopulmonary bypass and their relationship to the bleeding time and nonsurgical blood loss.

The hemostatic dysfunction induced by cardiopulmonary bypass is due, in part, to a platelet dysfunction evidenced by a postoperative extension of the bleeding time; it leads to increased postoperative blood loss and morbidity. This study, which was conducted in 85 patients undergoing cardiopulmonary bypass, was designed to characterize the hematologic changes during and after cardiopulmonary bypass and to elucidate the relationships between these changes, the extension of the bleeding time, and the magnitude of the postoperative nonsurgical blood loss. Variables were measured before, during, and 2, 24, 48, and 72 hours after cardiopulmonary bypass. Univariate and multivariate analyses were performed with either the 2-hour postbypass bleeding time or the 4-hour postbypass blood loss as the dependent variables. The reversal of the extension of the bleeding time in the postoperative period was accompanied by a significant increase in the mean platelet volume and by a significant increase in the level of thromboxane B2 measured in the blood shed from the site of the bleeding time determination. The postoperative bleeding time correlated with the postoperative blood loss, and both parameters were dependent on the duration of cardiopulmonary bypass. In addition, the postoperative bleeding time correlated with the skin temperature and the plasma level of D-dimer, while the postoperative blood loss also correlated with temperature and the plasma levels of C3. These data establish a direct relationship between the postoperative bleeding time, the postoperative blood loss, and temperature. They indicate that the reversal of the postoperative extension of the bleeding time is due in part to rewarming and to the release of larger platelets into the circulation, and they suggest that hyperfibrinolysis and complement activation may play an important role in the cardiopulmonary bypass-induced platelet dysfunction.

Bleeding Time↗
PubMed1992

Inactivation of viruses in red cell and platelet concentrates with aluminum phthalocyanine (AIPc) sulfonates.

Aluminum phthalocyanine tetrasulfonates (AIPcS) are photoactive compounds with absorption maxima at 665-675 nm. The inactivation of viruses (vesicular stomatitis virus, VSV; human immunodeficiency virus, HIV) added to either whole blood or red blood cell concentrates (RBCC) and platelet concentrates (PC) on treatment with tetrasulfonated AIPc (AIPcS4) was evaluated. Treatment of RBCC with 10 microM AIPcS4 and 44 J/cm2 visible light resulted in the inactivation of greater than or equal to 10(5.5) infectious doses (TCID50) of cell-free VSV, greater than or equal to 10(5.6) TCID50 of cell-associated VSV, and greater than or equal to 10(4.7) TCID50 of cell-free sindbis virus. Both greater than or equal to 10(4.2) TCID50 of cell-free and greater than or equal to 10(3.6) TCID50 of cell-associated forms of HIV were also shown to be inactivated. Encephalomyocarditis virus, used as a model for nonenveloped viruses, was not inactivated. Equivalent virus kill with Photofrin II required a substantially higher concentration of dye and longer exposure to visible light. Following AIPcS4 treatment, red cell integrity was well maintained as judged by the low level (less than 2%) of hemoglobin release immediately following treatment and on subsequent storage, by measurements of erythrocyte osmotic fragility, and by the normal recovery and circulatory survival on infusion of treated, autologous red blood cells in baboons. Treatment of PC with 10 microM AIPcS4 and 44 J/cm2 visible light also resulted in effective virus kill (greater than or equal to 10(5.5) TCID50) of VSV; however, both the rate and extent of platelet aggregation in response to collagen addition declined by at least 50%. Based on these results, further characterization of AIPcS4-treated RBCC is justified.

Animals↗
PubMed1991

Nasally-administered progesterone: comparison of ointment and spray formulations.

The aim of the study was to compare the bioavailability and clinical usefulness of progesterone (P) administered nasally in spray or ointment form. Twenty healthy post-menopausal women were randomly allocated to treatment by either intranasal spray (4 doses of an oil-based P solution at a concentration of 2 mg/0.1 ml, corresponding to a total dose of approximately 11 mg of P) or an ointment (quantity 0.1 ml, P concentration 20 mg/0.1 ml). Circulating P levels were calculated at various time intervals following administration. The spray formulation yielded a mean maximum concentration (CMax) of 3.75 ng/ml after 60 min (TMax) and the area under the curve (AUC) 0-720 min was 1481.6 +/- 343 ng.h/ml. The ointment yielded a mean CMax of 1.19 ng/ml at TMax = 30 min, the AUC 0-720 value being 404.35 +/- 148 ng.h/ml. The study findings confirmed that the intranasal route is a potentially useful alternative for the administration of natural sex steroid hormones, making it possible to avoid first-pass liver metabolism. P administered by spray showed greater bioavailability than it did when administered in ointment form, while both formulations seemed to be acceptable to patients and were probably clinically safe.

Administration, Intranasal↗
PubMed1991

Progesterone administration by nasal spray.

The bioavailability and the clinical usefulness of the P administered by nasal spray were investigated. Ten healthy menopausal women received an IN spray administration (4 doses of an oleic P solution 20 mg/mL, corresponding to nearly 11.2 mg of P) and the circulating P levels were calculated. Sixty minutes after administration, the maximum concentration (CMax, 3.75 +/- 0.214 ng/mL) was reached. High P levels (greater than 2 ng/mL) lasted until 360 minutes, and the AUC 0 to 720 was 1,481.6 +/- 343 ng.h/mL. Progesterone administration by spray formulation has proven to be effective in reaching therapeutic levels and to be acceptable to patients and, probably, clinically safe.

Absorption↗
PubMed1990

A rapid evaluation of tetracycline and its dehydration products by UV derivative spectrophotometry.

This paper described a rapid ultraviolet spectrophotometric assay for simultaneous determination of tetracyclines (TC + ETC) and their anhydroderivatives (ATC + EATC), by using third- or fourth-derivative spectra recorded on samples in ethanol or dioxane. The analytical procedures are based on linear relationships between specific peak-trough values and the relative concentrations of tetracycline and of ATC-EATC, in mixtures containing TC, ATC and EATC. The toxic EATC can be estimated about half of the anhydrotetracyclines concentration values. The determination limit of anhydroderivatives is 0.05%. A simple purity test of the antibiotic is also reported. Accuracy, precision and linearity are discussed. The method is particularly applicable to routine analysis of products containing TC, in bulk and in some pharmaceutical formulations.

Capsules↗
PubMed1988

The 24-hour posttransfusion survival and lifespan of autologous baboon red cells treated with inositol hexaphosphate-polyethylene glycol or inositol hexaphosphate-adenosine triphosphate-polyethylene glycol to decrease oxygen affinity.

Baboon red cells were treated to reduce oxygen affinity by an osmotic-pulse procedure using dimethyl-sulfoxide. Inositol hexaphosphate (IHP) alone or IHP and adenosine triphosphate (ATP) were incorporated into the red cells in the presence of polyethylene glycol (PEG). The procedure produced variable increases in the red cell P50 value, i.e., the partial pressure of oxygen at which 50% of the hemoglobin was saturated. The effect of treatment of autologous baboon red cells on the 24-hour posttransfusion survival value and lifespan T50 value was measured using a double-label procedure. The data demonstrate that the increase in the P50 value of treated red cells was negatively correlated with the 24-hour posttransfusion survival value; the higher the P50 value, the poorer the 24-hour posttransfusion survival value. The 24-hour posttransfusion survival value for nontreated baboon red cells was 90% and the T50 value was 14 days. The IHP-ATP-PEG-treated red cells had significantly higher red cell ATP levels than did IHP-PEG-treated red cells. The 24-hour posttransfusion survival value was 68% for the IHP-ATP-PEG treated red cells and 52% for the IHP-PEG-treated red cells when the increase in P50 ranged from 10 to 20 mm Hg; the lifespan T50 value for both the IHP-ATP-PEG-treated red cells and the IHP-PEG-treated red cells was 15 days. Osmotic pulse treatment produced significant red cell injury manifested by the 24-hour posttransfusion survival value. However, modification of the RBC with IHP-PEG or IHP-ATP-PEG to decrease hemoglobin affinity for oxygen did not affect their lifespan.

Adenosine Triphosphate↗
PubMed1987

Hypothermia-induced reversible platelet dysfunction.

Baboons that were subjected to systemic hypothermia at 32 C had an arm skin temperature of 27.3 C and bleeding time of 5.8 minutes. With local warming of the arm skin to 34 C, the bleeding time was 2.4 minutes. In normothermic baboons with arm skin temperature of 34.6 C, the bleeding time was 3.1 minutes. Local cooling of the arm skin to 27.6 C produced a bleeding time of 6.9 minutes. Increasing the skin temperature of the arm in hypothermic baboons to 38.9 C and in normothermic baboons to 40.1 C reduced bleeding times to 2.1 and 2.3 minutes, respectively. In both hypothermic and normothermic baboons there was a negative and significant correlation between the bleeding time and the arm skin temperature and the thromboxane B2 level in the shed blood obtained at the template bleeding time site. There was a significant positive correlation between the thromboxane B2 level in the shed blood and the arm skin temperature. Both in-vivo and in-vitro studies have shown that the production of thromboxane B2 by platelets is temperature-dependent, and that a cooling of skin temperature produces a reversible platelet dysfunction. Data also suggest that when a hypothermic patient bleeds without surgical cause, skin and wound temperature should be restored to normal before the administration of blood products that are not only expensive but may also transmit disease.

Animals↗