Properties of some steroid glycosyl transferases from rabbit tissues.
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Animals↗
Biomedical subjects
R S Labow
Publications and source records attributed to R S Labow.
Platelet storage. Effects of leachable materials on morphology and function.
A polyolefin plastic (PL 732) bag formulated without liquid plasticizer allows storage of platelets for 5 and, now, up to 7 days. In order to assess the leaching of compounds from this new plastic, extracts of the supernatant from platelet concentrates stored in these bags were analyzed by high-performance liquid chromatography, mass spectrometry, and gas-liquid chromatography. A leachable material was detected and identified as di(2-ethylhexyl) phthalate (DEHP). During the sterilization process, migration of the DEHP occurs from the polyvinylchloride (PVC) bags into the PL 732 plastic bag. The level of DEHP was 12-fold less in the extracts of PC supernatant stored in the PL 732 bag than those in the polyvinyl chloride (PL 146) plastic bags which were used previously for platelet storage. Platelets stored in low DEHP concentrations in the PL 732 bags were composed of 10 to 35 percent of unclassifiable shapes. These shape changes were not observed in higher concentrations of plasticizer, although the morphology scores decreased during storage in PL 146 as well. This effect on morphology was not related directly to the dose of DEHP. When platelet membranes were isolated from platelets stored in the presence of radiolabeled DEHP, the amount of bound 14C-DEHP was found to be directly proportional to the concentration of DEHP in the plasma supernatant. However, while there was a linear relationship between the protein concentration in the membrane fraction and the amount of bound DEHP, no specific DEHP binding site could be identified by electrophoresis of the solubilized platelet membranes.
Blood Platelets↗
The effects of irradiation on platelet function.
Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products.
Blood Platelets↗
Benzoporphyrin derivative monacid ring A (Verteporfin) alone has no inhibitory effect on intimal hyperplasia: in vitro and in vivo results.
Benzoporphyrin derivative monoacid ring A (Verteporfin, BPD-MA), a photosensitizing drug, has been suggested as having inhibitory effects on smooth muscle cell (SMC) proliferation in rabbit aortic intimal injuries. The effect of BPD-MA on vascular SMCs in the absence of light stimulation in vitro and in vivo was studied using models of intimal hyperplasia. Human SMCs were incubated with BPD-MA for 4 h in darkness. A small (20%) but significant decrease in viability (n =42,p < .05) was noted for BPD-MA concentrations above 15 microg/mL. This was an all-or-none phenomenon with no further decrease in viability at higher concentrations. Treatment with BPD-MA was also carried out in vivo using a balloon injury model of intimal hyperplasia in rabbit aortas. Thirty-three rabbits were randomized into five groups and given intravenous BPD-MA (2 mg/kg) according to the following schedule: Group 1 (n = 8), BPD-MA 25 min prior to injury; Group 2 (n = 8), BPD-MA 25 min prior to injury plus a second dose 4 weeks later; Group 3 (n = 4), BPD-MA immediately postinjury; Group 4 (n = 7), BPD-MA immediately postinjury plus a second dose 4 weeks later; or Group 5 (n = 6), no drug (control group). No statistically significant difference was seen in the amount of intimal hyperplasia that developed in the five groups.
Angioplasty, Balloon↗
Use of the University of Wisconsin solution for the preservation of cell organelle activities in rat heart and lungs.
BACKGROUND: The University of Wisconsin storage solution has been successful in some model systems in extending the storage period of heart-lung grafts for transplantation. METHODS: In this study an aerated preparation of rat heart and lung was stored for 24 hours at 4 degrees C in either University of Wisconsin or St. Thomas' Hospital solution. Cell organelles (reticular, mitochondrial, and cell membrane fractions) were isolated from the stored hearts and lungs. Protein yield and enzyme activities were assayed for each cell organelle (reticular fractions: Ca(2+)-ATPase, NADPH-cytochrome C reductase; mitochondria: Ca(2+)-ATPase, cytochrome C oxidase; cell membrane fraction: Na+,K(+)-ATPase, p-nitrophenylphosphatase) as a measure of the recovery of function. RESULTS: Only the cell membrane fraction of heart and lung was not affected by storage in either St. Thomas' Hospital or University of Wisconsin solution with respect to protein yield (milligrams per gram of homogenate) or enzyme activities (nanomole per milligram per minute). The reticular fraction was the most sensitive to storage, with both protein yield and enzyme activities being significantly reduced in both the heart and the lung stored in University of Wisconsin of St. Thomas' Hospital solution (p < 0.05). CONCLUSION: The mitochondrial fraction was not preserved in lung in either St. Thomas' Hospital or University of Wisconsin solution but was preserved in the heart stored in St. Thomas' Hospital solution. These criteria provide preliminary screening for a superior solution that may then be used in more complicated transplantation models to more fully assess cardiac and pulmonary function.
4-Nitrophenylphosphatase↗