Biomedical subjects

A D Gray

Publications and source records attributed to A D Gray.

8 recordsLinked to original sources

PubMed2001

Clean-chemistry synthesis of 2-tetralones in a single-stage acylation-cycloalkylation process.

The preparation of substituted-2-tetralones by direct reaction of a 1-alkene with a substituted phenylacetic acid in a reaction system of trifluoroacetic anhydride (TFAA) and phosphoric acid is described. This single-stage process involves in situ formation of a mixed anhydride of the phenylacetic acid and acylation of the alkene by this species followed by cycloalkylation of the aromatic ring. This is a cleaner approach to the synthesis of 2-tetralones compared to Friedel-Crafts aliphatic acylation-cycloalkylation in that use of thionyl chloride, aluminum trichloride, and a chlorinated hydrocarbon solvent is eliminated. In addition, the atom efficiency is augmented by recovery of the spent TFAA as trifluoroacetic acid (TFA) and conversion of this back to TFAA by dehydration.

Journal Article↗

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↗

PubMed1991

Evaluation of the Quantitative Buffy Coat (QBC) method to detect malaria-infected red blood cells.

The conventional thin blood film method of detecting malaria is a long and tedious procedure, requiring significant technical expertise. In this study, we compared the Quantitative Buffy Coat (QBC) capillary tube method, which requires only minimal technical training, to the thin blood film method, and found it to be not only more rapid but also more sensitive than the thin blood film method in the detection of parasitized red blood cells. We do not suggest that the QBC capillary method can replace the conventional thin blood film method for the detection of malaria since it does not identify or quantitate the parasite species, only that it would serve as a valuable screening test.

Animals↗

PubMed1989

Role of thromboxane in interleukin 2-induced lung injury in sheep.

Interleukin (IL)-2 administration leads to respiratory dysfunction due to increased vascular permeability. This study examines the role of thromboxane (Tx)A2 in IL-2 induced lung injury in sheep with chronic lung lymph fistulae. This preparation enables evaluation of permeability prior to the development of gross edema. IL-2, 10(5) units/kg (n = 6), or its excipient control (n = 5) was given as an i.v. bolus over 2 min. After 2 h of IL-2 administration, plasma TxB2 increased from 168 to 388 pg/ml (P less than 0.05) and lung lymph TxB2 from 235 to 694 pg/ml (P less than 0.05). Mean pulmonary artery pressure (MPAP) rose from 13 to 29 mm of Hg (P less than 0.05) at 30 min and remained elevated for 4 h while the pulmonary artery wedge pressure was unchanged at 4 mm of Hg. Arterial oxygen tension (PaO2) fell from 88 to 77 mm of Hg (P less than 0.05). Lung lymph flow (QL) rose from 2.2 to 3.8 ml/30 min (P less than 0.05) at 1 h and to 6.4 ml/30 min at 3 h. This rise coincided with an increase in the lymph/plasma (L/P) protein ratio from 0.67 to 0.77 (P less than 0.05). In contrast, the non-IL-2-infused sheep (n = 3) recruitment of the lung vasculature by left atrial balloon inflation led to a rise in QL from 2.4 to 8.2 ml/30 min, whereas the L/P ratio declined from 0.62 to 0.25, suggesting that the protein-rich lymph flow after IL-2 administration reflected increased microvascular permeability. In further proof of an increase in permeability, IL-2 administration into sheep (n = 2) with an inflated left atrial balloon led, after a pressure-independent L/P protein ratio had been achieved, to an increase in L/P protein ratio and decrease in protein reflection coefficient. At 2 h after IL-2, the blood leukocyte count fell from 8156 to 4375/mm3 (P less than 0.05) primarily due to a 73% drop in lymphocytes. The platelet count declined from 292 to 184 x 10(3)/mm3 (P less than 0.05). Body temperature rose from 38.9-40.3 degrees C (P less than 0.05), and shaking chills were common. Pretreatment with the Tx synthetase inhibitor OKY 046 (n = 7) lowered baseline plasma and lymph TxB2 levels to 22 and 52 pg/ml (P less than 0.05) and prevented the IL-2-induced increase in plasma and lung lymph TxB2 (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1989

The safety and therapeutic effectiveness of human red cells stored at -80 degrees C for as long as 21 years.

Human red cells frozen by various methods have been stored in the frozen state at -80 degrees C for as long as 21 years. This report discusses: red cells frozen with 42 percent weight per volume (wt/vol) glycerol in an ionic medium in a polyvinylchloride (PVC) plastic bag using the Cohn method; red cells frozen with 45 percent wt/vol glycerol in a low ionic medium in a PVC plastic bag using the Huggins method; red cells frozen with 40 percent wt/vol glycerol in an ionic medium in a polyolefin plastic bag using the Meryman-Hornblower method; and red cells frozen with 40 percent wt/vol glycerol in an ionic medium in a standard 600-ml or an elongated 800-ml PVC plastic primary collection bag with an adapter port using the Naval Blood Research Laboratory (NBRL) method. After frozen storage for as long as 21 years by the four methods described above, the thawed red cells were deglycerolized with 50 to 150 ml of 12 percent sodium chloride and 1.5 to 2.0 l of sodium chloride-glucose or sodium chloride-glucose-phosphate solution. After washing and storage at 4 degrees C for 24 hour, the red cells had a mean freeze-thaw-wash recovery value of 90 percent, a mean 24-hour posttransfusion survival value of 85 percent, a mean index of therapeutic effectiveness of 75 percent, normal or slightly impaired oxygen transport function, and minimal hemolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗

PubMed1985

Quantitative differential agglutination method using the Coulter Counter to measure survival of compatible but identifiable red blood cells.

The method described here using a centrifuge and Coulter Cell Counter for the quantitative differential agglutination of human red cells uses commercial anti-A and anti-B antisera for the ABO system, and for the Rh system a commercial anti-D serum, a low ionic strength solution and an anti-human IgG antiserum. We compared this Coulter Counter method with the Technicon AutoAnalyzer method which utilizes bromelin and polyvinyl pyrrolidone, and anti-A, anti-B and anti-CD antisera, and found this new method to be the simpler of the two. The nonagglutinable count with the Coulter Counter was 1.07% for A1 red cells, 2.26% for A2 red cells, 1.06% for B red cells, and 1.78% for Rh-positive red cells, results similar to those seen with the Technicon AutoAnalyzer. Results with the Coulter Counter method were consistently accurate whether the ACD red cells were studied on the day of collection, after 10 days of 4 degrees C storage, or after 4 degrees C storage for up to 6 days followed by cryopreservation with 40% (w/v) glycerol at-80 degrees C, thawing and washing. In this study, red cell samples obtained from recipients who had received compatible but identifiable donor red cells were frozen with 40% glycerol and stored at-80 degrees C for 10 months, thawed and washed. Survival measurements on these washed previously frozen red cells were similar to the values in liquid-stored red cells.

Agglutination Tests↗

PubMed1981

Quantification of hyperbaric oxygen-induced toxicity utilizing a malarial system.

This study was undertaken in recognition of the need to develop quantitative systems to evaluate the toxicity associated with hyperbaric oxygen (HBO) exposure. Malaria-infected (P. berghei berghei) mice were briefly exposed to 100% oxygen at 3 ATA on day 10 of infection. At 25, 48, and 72 h thereafter, the levels of circulating erythrcytes and percent parasitized RBC were monitored and compared to those of infected non-exposed controls. The total erythrocyte counts of the infected HBO-exposed and non-exposed mice did not differ significantly. In contrast, percent parasitized cells in the oxygen-exposed mice were lowered to 55-60% control values at 24, 48, and 72 h. The mechanism of this difference needs further study, but we believe that P. berghei-infected erythrocytes are preferentially hemolyzed as a consequence of HBO exposure. this mode system is useful in the study of HBO-induced toxicity because of its high degree of selectivity and sensitivity and its amenability to strict quantification over a period of at least several days.

Animals↗

PubMedDate not supplied

The 24-hour posttransfusion survival, oxygen transport function, and residual hemolysis of human outdated-rejuvenated red cell concentrates after washing and storage at 4 degrees C for 24 to 72 hours.

Red cell concentrates with hematocrit values of 80 +/- 5 percent were stored at 4 degrees C either in citrate-phosphate-dextrose for 22 to 28 days or in citrate-phosphate-dextrose-adenine-one for 35 to 39 days. After storage, the red cells had reduced 2,3-diphosphoglycerate and adenosine triphosphate levels, and biochemical treatment with a solution called PIPA was used to restore these levels. The red cells were not preserved further, but instead were washed after rejuvenation with an unbuffered sodium chloride-glucose solution, pH 5.0, for in vivo studies, and with a buffered sodium chloride-glucose-phosphate solution, pH 6.8, for comparative in vitro studies. The red cells were stored in the wash solution at 4 degrees C for 72 hours after washing. Red cell recovery after washing was about 95 percent. Twenty-four-hour posttransfusion survival value was about 80 percent, and the index of therapeutic effectiveness was greater than 75 percent. These biochemically modified washed red cells exhibited higher than normal P50 values, even after 3 days of postwash storage at 4 degrees C. The units that were washed with the sodium chloride-glucose solution with a pH of 5.0 exhibited a greater degree of hemolysis after 3 days of postwash storage at 4 degrees C than did the units that were washed with the sodium chloride-glucose-phosphate solution with a pH of 6.8.(ABSTRACT TRUNCATED AT 250 WORDS)

2,3-Diphosphoglycerate↗