Neovascularization during venous thrombosis organization: a preliminary study.
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PURPOSE: Thrombus organization after venous thromboembolism leading to recanalization occurs at a variable rate. The angiogenic chemokine interleukin-8 (IL-8) has been found in thrombus months after thrombus initiation. We hypothesize that thrombus organization involves neovascularization and leukocyte influx and that IL-8 administered at thrombus induction will promote thrombus organization. METHODS: A group of rats underwent inferior vena caval occlusive thrombosis. At thrombus induction and every 24 hours, the rats were administered IL-8 (1 microgram) or serum albumin. The rats were killed at either day 4, day 8, or day 12, and, at death, colloidal carbon was perfused via the heart. The inferior vena cava was isolated, measured, weighed, and formalin fixed. The sections were stained with anti-polymorphonuclear leukocyte antibody, the endothelial marker factor VIII-related antigen, and with hematoxylin and eosin. Thrombus neovascularization (colloidal carbon) with morphometric analysis was normalized to the total thrombus area. In addition, the rats underwent perfusion with fluorescein isothiocyanate dextran (molecular weight, 150,000) at death to correlate with colloidal carbon perfusion, and thrombus fluorescence was determined. RESULTS: Thrombus cellularity initially involved neutrophils, followed by monocytes. Significantly more neutrophils, monocytes, and cells that were defined as spindle shaped (fibroblasts and endothelial cells) were noted in the animals treated with IL-8. Neovascularization was significantly increased at day 4 in the animals treated with IL-8 versus the animals treated with serum albumin and was corroborated with a significant increase in thrombus fluorescein isothiocyanate dextran fluorescence at day 4 in the rats treated with IL-8. Colloidal carbon perfusion was noted within vascular channels without extravasation and colocalized with factor VIII-related antigen. CONCLUSION: This study shows that thrombus organization involves neovascularization and that IL-8 augments thrombus organization. (+info)
Amsorb: a new carbon dioxide absorbent for use in anesthetic breathing systems.
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BACKGROUND: This article describes a carbon dioxide absorbent for use in anesthesia. The absorbent consists of calcium hydroxide with a compatible humectant, namely, calcium chloride. The absorbent mixture does not contain sodium or potassium hydroxide but includes two setting agents (calcium sulphate and polyvinylpyrrolidine) to improve hardness and porosity. METHODS: The resultant mixture was formulated and subjected to standardized tests for hardness, porosity, and carbon dioxide absorption. Additionally, the new absorbent was exposed in vitro to sevoflurane, desflurane, isoflurane, and enflurane to determine whether these anesthetics were degraded to either compound A or carbon monoxide. The performance data and inertness of the absorbent were compared with two currently available brands of soda lime: Intersorb (Intersurgical Ltd., Berkshire, United Kingdom) and Dragersorb (Drager, Lubeck, Germany). RESULTS: The new carbon dioxide absorbent conformed to United States Pharmacopeia specifications in terms of carbon dioxide absorption, granule hardness, and porosity. When the new material was exposed to sevoflurane (2%) in oxygen at a flow rate of 1 l/min, concentrations of compound A did not increase above those found in the parent drug (1.3-3.3 ppm). In the same experiment, mean +/-SD concentrations of compound A (32.5 +/- 4.5 ppm) were observed when both traditional brands of soda lime were used. After dehydration of the traditional soda limes, immediate exposure to desflurane (60%), enflurane (2%), and isoflurane (2%) produced concentrations of carbon monoxide of 600.0 +/- 10.0 ppm, 580.0 +/- 9.8 ppm, and 620.0 +/-10.1 ppm, respectively. In contrast, concentrations of carbon monoxide were negligible (1-3 ppm) when the anhydrous new absorbent was exposed to the same anesthetics. CONCLUSIONS: The new material is an effective carbon dioxide absorbent and is chemically unreactive with sevoflurane, enflurane, isoflurane, and desflurane. (+info)
Prevention of low temperature denaturation injury in T4Bo phage by low concentrations of traditional cryoprotective additives.
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The well known cryoprotective additives glucose, sucrose, glycerol, dimethyl sulphoxide, polyvinylpyrrolidone, dextran and ammonium acetate have been found to prevent inactivation of T4Bo phage frozen in sodium bromide solutions. Their protective effects in this experimental system could not be accounted for by a colligative mechanism. It is proposed that they may act by modifying the structure of the unfrozen aqueous phase rather than by direct interaction with the phage. (+info)
Antibacterial activity of antibiotic-soaked polyvinylpyrrolidone-grafted silicon elastomer hydrocephalus shunts.
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If shunts, inserted for the relief of hydrocephalus, are pretreated with antimicrobials, the incidence of shunt-associated infections (SAI) may be reduced. The duration of the antibacterial activity of shunts, made from conventional silicon elastomer (SE) or from SE grafted with the hydrogel polyvinylpyrrolidone (SEpvp), which had been soaked in various antibiotics, was assessed in vitro. For any antibiotic or combination, using an arbitrary breakpoint (aBP), SEpvp remained antibacterially active for longer periods than SE. Bacterial adherence to either shunt was prevented during the period of antibacterial activity. Thus, the aBP is a good indicator of the capacity of antimicrobial-treated shunts to prevent bacterial colonization in vitro. Hydrogel-grafting of shunts may be useful in preventing SAI. (+info)
The use of silane-coated silica particles for density gradient centrifugation in in-vitro fertilization.
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Silane-coated silica particles (PureSperm) were evaluated as an alternative to Percoll for gradient separation of spermatozoa, for use in assisted reproduction. Recovery of motile and morphologically normal spermatozoa after using a four-layer Percoll and a two- and four-layer PureSperm gradient respectively was recorded. In-vitro fertilization (IVF) results after using PureSperm for the sperm preparation were also evaluated. No difference in sperm recovery or sperm motility was found when comparing the use of Percoll and the four-layer gradient of PureSperm. When using a two-layer PureSperm gradient, motility was significantly decreased (P < 0.05) compared to Percoll. Normal sperm morphology increased from 8-17.2% after using Percoll and to 12.7% and 11.4% after using a four-layer and a two-layer PureSperm gradient respectively. All gradient preparations showed a significant decrease in the teratozoospermia index compared to the ejaculate (P < 0.01). No significant differences in IVF results regarding fertilization and pregnancy rates were found when PureSperm or the swim-up technique were used for the sperm preparation. PureSperm seems to be an acceptable alternative to Percoll but although the percentage of sperm recovery was higher after PureSperm we still recommend the swim-up technique to be the first choice, as a higher percentage of progressive motile spermatozoa is obtained without using other chemicals than IVF culture medium. (+info)
Biomaterial-associated persistence of Staphylococcus epidermidis in pericatheter macrophages.
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Biomaterial surfaces may be modified to reduce bacterial adhesion. The susceptibility in mice to Staphylococcus epidermidis infection in tissue surrounding the commonly used catheter materials-silicon elastomer (SE), polyamide (PA), and their surface-modified polyvinylpyrrolidone (PVP)-grafted derivatives, SE-PVP and PA-PVP, respectively-was assessed. Abscesses developed around SE-PVP. Around SE, PA, and PA-PVP catheters, no signs of infection were observed, although mice carrying PA-PVP developed septicemia after 14-21 days. S. epidermidis was cultured from the tissue surrounding PA-PVP segments. Cells around PA-PVP segments containing large numbers of bacteria were identified as macrophages by use of immunohistochemistry and electron microscopy. This persistence of intracellular bacteria was also observed around SE-PVP, SE, and PA catheters, although to a lesser extent. The cytokine profiles around the 4 materials were different. Implanted biomaterial induces an inflammatory response favorable to the persistence of S. epidermidis. Intracellular persistence of bacteria inside macrophages may be a pivotal process in the pathogenesis of biomaterial-associated infection. (+info)
Relationship between biological activities of polymers. I. Immunogenicity, C3 activation, mitogenicity for B cells and adjuvant properties.
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The effect of thirteen compounds on C3 activation, mitogenicity for B lymphocytes and on the immune response was tested. Only two of the compounds tested, polyinosinic acid and a high molecular weight polyethylenesulphate induced C3 conversion, while eleven out of the thirteen compounds (negative charged immunogenic or non-immunogenic polymers including the three C3 active compounds) stimulated thymidine incorporation in B lymphocytes. The non-charged (T-independent) immunogens dextran and polyvinylpyrrolidone neither activated C3 nor BP lymphocytes. With the exception of single-stranded polyribonucleic acids, the compounds stimulating DNA synthetis in B cells enhanced the response of the mice to a suboptimal dose of sheep red blood cells. In conclusion C3 activation, intrinsic (T-independent) immunogenicity and B-cell stimulation are not correlated properties. However, B-cell mitogenicity and adjuvanticity seem to be related. (+info)
High developmental rates of vitrified bovine oocytes following parthenogenetic activation, in vitro fertilization, and somatic cell nuclear transfer.
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Successful cryopreservation of mammalian oocytes would provide a steady source of materials for nuclear transfer and in vitro embryo production. Our goal was to develop an effective vitrification protocol to cryopreserve bovine oocytes for research and practice of parthenogenetic activation, in vitro fertilization, and nuclear transfer. Bovine oocytes matured in vitro were placed in 4% ethylene glycol (EG) in TCM 199 plus 20% fetal bovine serum (FBS) at 39 degrees C for 12-15 min, and then transferred to a vitrification solution (35% EG, 5% polyvinyl-pyrrolidone, 0.4 M trehalose in TCM 199 and 20% FBS). Oocytes were vitrified in microdrops on a precooled (-150 degrees C) metal surface (solid-surface vitrification). The vitrified microdrops were stored in liquid nitrogen and were either immediately thawed or were thawed after storage for 2-3 wk. Surviving oocytes were subjected to 1) parthenogenetic activation, 2) in vitro fertilization, or 3) nuclear transfer with cultured adult fibroblast cells. Treated oocytes were cultured in KSOM containing BSA or FBS for 9 to 10 days. Embryo development rates were recorded daily and morphologically high-quality blastocysts were cryopreserved for nuclear transfer-derived embryos at Day 7 or Day 8 of culture. Immediate survival of vitrified/thawed oocytes varied between 77% and 86%. Cleavage and blastocyst development rates of vitrified oocytes following in vitro fertilization or activation were lower than those of the controls. For nuclear transfer, however, vitrified oocytes supported embryonic development as equally well as fresh oocytes. (+info)