Applications of ultraviolet light in the preparation of platelet concentrates

Passenger lymphocytes in platelet concentrates (PCs) may induce the formation of lymphocytotoxic antibodies (LCTAbs) and subsequent refractoriness to platelet transfusions. Ultraviolet (UV) irradiation can prevent lymphocytes' acting as stimulator or responder cells in mixed-lymphocyte reactions (MLRs) and could theoretically prevent LCTAb formation in vivo. A system has been devised for the delivery of UV irradiation to PCs; platelet storage characteristics and MLRs were evaluated in UV-irradiated PCs harvested from healthy donors with the Haemonetics V50 and PCS cell separators. MLR and response to phytohemagglutinin stimulation were abolished by a dose of 3000 joules per m2 at a mean wavelength of 310 nm. Platelet aggregatory responses to adenosine diphosphate (ADP), ristocetin, collagen and epinephrine, hypotonic shock response, and pH showed no important differences when control PCs and PCs irradiated as above were compared during 5 days of storage in Fenwal PL-1240 packs. Lactate production during storage was significantly higher in UV-treated PCs (p less than 0.001), but values did not exceed 20 mmol per L. UV transmission at 310 nm in standard blood product containers, including the Fenwal PL-146, PL-1240, and PL-732, was low (less than 30%), but it was acceptable in the Delmed Cryostorage and DuPont SteriCell packs (greater than 50%). UV irradiation may provide a simple and inexpensive means of producing nonimmunogenic PCs.     

The acute effects of pneumonectomy on pulmonary vascular impedance in the dog

Pulmonary vascular impedance is a measure of the pulsatile characteristic of pressure and flow that occurs in the proximal pulmonary arteries. Pulmonary vascular resistance (PVR) is most influenced by the distal circulation of the lung. This study was performed to evaluate the changes that occurred in pulmonary vascular impedance, as well as in other hemodynamic variables, following pneumonectomy by a closed-chest method in 10 anesthetized dogs. The following observations were made (numbers compare mean values for the 10 dogs before and after pneumonectomy): (1) PVR increased from 447 to 761 dyne sec cm-5 (p = .02); (2) the oscillatory work of the right ventricle increased from 1.23 to 1.76 J/min (p = .006); (3) the mean pulmonary artery pressure increased from 14 to 18.8 mm Hg (p = .0001); and (4) cardiac output and heart rate remained unchanged. Surprisingly, the estimated characteristic impedance (the impedance to oscillatory flow in the proximal bed) did not change significantly (279 to 296 dyne sec cm-5). This observation cannot be explained by the usual lumped compartmental models classically used to characterize the pulmonary vascular bed.     

Double-lumen needle for percutaneous ureteral pressure-flow studies

Ureteral perfusion studies in patients without preexisting renal access currently must be intermittently interrupted for intrarenal pressure measurement. A double-lumen needle has been successfully placed in four patients (two with native and two with transplanted kidneys). This permits simultaneous perfusion and intrarenal pressure monitoring yet maintains the safety and ease of use of a single skinny needle.     

Regional heterogeneity of elastin and collagen gene expression in intralobar arteries in response to hypoxic pulmonary hypertension as demonstrated by in situ hybridization.

In situ hybridization was used to determine the morphologic distribution of tropoelastin and alpha 1(I) procollagen mRNA expression in elastic intralobar arteries from neonatal calves with hypoxic pulmonary hypertension induced by a 15-day exposure to a simulated altitude of 1500 m. In vessels from normotensive control animals, low levels of hybridizable tropoelastin mRNA were detected in smooth muscle cells (SMC) of the inner media associated with large elastic lamellae. Compared to control arteries, vessels from hypertensive animals demonstrated a markedly different pattern of hybridization. In these arteries, strong hybridization signals for tropoelastin mRNA were seen in SMC lying between the elastic lamellae of the outer media, and the density of labeling associated with these medial cells decreased progressively toward the lumen. Endothelial and adventitial cells in both control and hypertensive arteries were negative for tropoelastin mRNA. Type I procollagen mRNA was dispersed through the media of control arteries, and in hypertensive calves, the hybridization signal was more intense and was unevenly distributed through the media similarly to that for tropoelastin mRNA. Adventitial cells were strongly positive for procollagen mRNA, and the signal was equally intense for both control and hypertensive arteries. Cells that had no detectable tropoelastin mRNA were noted in the outer media of both control and hypertensive vessels. These cells occurred as broad circumferential bands in the normotensive artery and as nodular foci in the hypertensive artery. Immunocytochemical studies with antibodies to smooth muscle specific actin, desmin, and vimentin demonstrated that cells within these foci, as well as tropoelastin mRNA-positive cells, were SMC. These studies demonstrate that expression of tropoelastin and procollagen mRNA was differentially stimulated by pulmonary hypertension within specific regions and SMC populations of the vascular wall.     

The effect of retinal isomers on the VER and ERG of vitamin A deprived rats

Male weanling Long-Evans and Sprague-Dawley rats were administered a vitamin A deficient diet and the electroretinogram (ERG) and/or visual evoked response (VER) were recorded weekly. After 6–10 weeks, when the animal showed a greatly decreased VER and ERG, the animal was injected intraperitoneally with a retinal isomer. Following dark adaptation for 18 hr, the ERG and VER were recorded. The rat was then sacrificed and the retina dissected. The retina was used for either solubilizing the visual pigment in 2% Ammonyx LO or extracting the retinals in methylene chloride. The visual pigments were characterized by the absorbance spectra and the retinal isomers were identified by high pressure liquid Chromatography (HPLC). The physiologically occurring isomers of retinal (11- cis and all- trans) are incorporated in the retina of deprived animals and the VER and ERG amplitudes for a given light intensity, diminished as a result of vitamin A deprivation, are restored to their normal values. 9- cis retinal is also incorporated into the retina, as shown by extraction of the retina with organic solvent and identification of the isomers by HPLC; a pigment is formed which has a λ_max blue-shifted from that of rhodopsin. The ERG and VER amplitudes of deprived rats injected with 9- cis retinal are restored to normal. No incorporation of 13- cis retinal into the retina is observed and the ERG and VER amplitudes are not significantly affected.