Inhibition by albumin of merocyanine 540-mediated photosensitization of platelets and viruses

The effect of the photosensitizer merocyanine 540 (MC 540) on platelets and on three marker viruses was examined to assess its potential in reducing virus transmission by blood products. The results demonstrated several deleterious effects of MC 540 (4-24 micrograms/mL) on platelet morphology and function in both the absence and presence of light (450-600 nm). Treatment of washed platelets with MC 540 in the dark resulted in a significant release of serotonin in the absence of added agonist, as well as a diminished response to thrombin as measured in vitro. In addition, photosensitization caused spontaneous platelet aggregation and release of 92 percent of the releasable serotonin without the addition of an agonist. Because photo-treatment of blood products is likely to be performed in a protein-rich medium, the influence of albumin on the phototoxic effects on platelets was assessed. Albumin added to the suspension medium at concentrations greater than or equal to 1.0 percent protected the platelets against the effects of MC 540 in the dark, whereas 5-percent albumin was required for protection against the phototoxic effects of MC 540 on the platelet response to thrombin. The antiviral activity of MC 540 and light was examined by using the lipid-containing viruses herpes simplex virus (HSV) and bacteriophages phi 6 and PM2. Of the lipid-enveloped viruses, HSV was 25 times more photosensitive to MC 540 than was phi 6 (15 micrograms/mL). PM2, which has an internal lipid layer, was almost 300 times less sensitive to MC 540 and light than was HSV.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduced bacteria on transplantable allograft skin after preparation with chlorhexidine gluconate, povidone-iodine, and isopropanol

A comparison was made of the residual microbiologic contamination on transplantable allograft skin for burn wound coverage taken from cadaver donors prepared by two different protocols. One group was prepared with povidone-iodine, detergent, and 70% isopropanol; the other was prepared with these agents and 4% chlorhexidine gluconate (CG). The skin from each of the donor bodies was removed from independently prepared body areas. Without CG, 13.7% of donor body areas were contaminated; with CG, only 5.6% were contaminated. The number of gram-positive bacterial species isolated from skin after CG preparation was dramatically reduced. The gram-positive bacterial contamination rate dropped from 12.1% to 2.2% of donor body areas, a drop of 82%. With CG, 12 of the 15 contaminant species were eliminated; and we saw a general reduction in the total number of contaminated body areas, a specific and pronounced reduction in gram-positive bacteria, and an increase from 86.3% to 94.4% in the amount of skin obtained from donor cadavers that tested negative for bacterial contamination.     

Circumcision — An Outdated and Unnecessary Procedure?

The origins and significance of circumcision, while somewhat obscure, do not seem to have any definite connection with medicine. This operation is now largely elective and constitutes certain risks to the newborn. It should therefore be restricted to children over three years of age whose foreskin remains unretractable. Routine hygiene is a much more acceptable alternative to circumcision.     

Increase in circulating colony-forming units-granulocyte-macrophage during large-volume leukapheresis: evaluation of a new cell separator

Peripheral blood stem cell (PBSC) collection was evaluated in two groups of normal donors who underwent large-volume leukapheresis on a blood cell separator. In Group A (n = 10), a 3-hour leukapheresis was performed. An average of 11.8 L of blood was processed with a mean flow rate of 66 mL per minute and a collection rate of 3 mL per minute. The PBSC product contained a mean 1.4 x 10(10) mononuclear cells (MNCs) (lymphocytes and monocytes), 1.27 x 10(6) colony-forming units-granulocyte-macrophage (CFUs-GM), and an average hematocrit of 4 percent (0.04). Postapheresis blood counts showed significant reductions in MNCs (19%) and platelets (45%) (p less than 0.005). Twenty-four hours later, the MNCs had returned to preapheresis levels. The platelet count returned to baseline only after 7 days. Circulating CFUs-GM remained stable for 3 days after apheresis but were increased twofold by Day 7 after apheresis (p = 0.025). Varying the product hematocrit from 1 percent (0.01) to 13.3 percent (0.13) did not change the number of CFUs-GM collected per MNC. In Group B (n = 4), an average of 18.5 L of blood was processed with a mean flow rate of 94 mL per minute and a collection rate of 3 mL per minute. The PBSC product was collected as four sequential samples and assayed for MNCs and CFUs-GM. Total MNCs averaged 1.7 x 10(10) (an increase of 21% relative to Group A) and CFUs-GM averaged 3.08 x 10(6) (an increase of 143%). Mean MNCs did not vary significantly among the four samples. However, CFUs-GM collected per minute (relative to the first sample) did show 1.26-fold (p = 0.001), 1.86-fold (p = 0.011), and 2.52-fold (p = 0.04) increases in the second, third, and fourth samples. These data suggest that MNCs and committed progenitor cells are recruited during large-volume leukapheresis. Moreover, there is a twofold increase in circulating CFUs-GM 1 week after apheresis.     

Pain associated with an adherent polyurethane wound dressing

Patient ratings of pain associated with autograft skin donor sites covered by an adherent polyurethane film dressing (Op-Site, Smith & Nephew) were collected using a modified Visual Analogue Scale. Analyses were undertaken to examine differences between pain levels under conditions of rest and activity, and with variations in application technique. It was found that with proper application and with at-rest patients, Op-Site-covered donor sites could be maintained relatively pain free. However, both specific conditions of application and increases in patient ambulation could result in the patient experiencing donor-site pain of an intensity comparable to concurrent burn-wound pain. To utilize fully their potential for pain control, the polyurethane film dressings must be appropriately applied and maintained, and their use coupled with an adequate analgesic regimen.     

尼莫地平胃内滞留漂浮型缓释片的研究

将尼莫地平先制成速释型固体分散体,再压制成胃内滞留漂浮型缓释片(NM-FSRT)。均匀设计法优选处方,并考察处方因素对尼莫地平释放的影响,在人体内对NM-FSRT进行了初步评价。结果表明优选处方于体外漂浮达10h,0.15～6h释放符合零级动力学。HPMC量越大,药物释放越慢,PEG 6000量越大,释放越快。饮食后NM-FSRT于胃内滞留时间约5h,空腹时约3h;对照非漂浮片饭后服滞留时间为3h,空腹2h排空。体内相对生物利用度为391.46%,MRT较普通片延长一倍多。     

Albumin gradients do not enrich Y-bearing human spermatozoa

The aim of this study was to evaluate objectively whether or not discontinuous albumin gradients enrich the proportion of Y-bearing human sperm. A blinded, collaborative trial design was employed whereby a licensed centre prepared the sperm fractions using licensed procedures, coded the sperm slides and then sent them to an independent laboratory for determination of the X:Y ratio in each sperm fraction using X and Y chromosome-specific probes and double label fluorescence in-situ hybridization (FISH). The identification codes and FISH results were collated by an independent third observer. Two albumin gradient methods which are currently used by licensed centres for male sex pre- selection, protocol 3 and modified protocol 3, were tested. Essentially the same results were obtained for the two methods. Highly motile sperm fractions were recovered from the albumin gradients, and the recoveries of motile spermatozoa (1.3-8.5%) were within the optimal range reported to produce maximal enrichment of Y-bearing spermatozoa. FISH analysis, however, revealed no enrichment for Y-bearing spermatozoa with either method, and the overall X:Y ratios were not significantly different from 1.0. Some samples showed marginal enrichment of Y-bearing spermaotozoa, whereas others showed marginal enrichment of X-bearing spermaotozoa. In conclusion, this collaborative study has demonstrated that the protocol 3 and modified protocol 3 albumin gradient procedures do not enrich Y-bearing spermatozoa. The clinical use of albumin gradients for male sex preselection should be reconsidered in the light of this and other evidence.