Nanoapatite-Loaded κ-Carrageenan/Poly(vinyl alcohol)-Based Injectable Cryogel for Hemostasis and Wound Healing.

Immediate control of excessive bleeding and prevention of infections are of utmost importance in the management of wounds. Cryogels have emerged as promising materials for the rapid release of medication and achieving hemostasis. However, their quick release properties pose the challenge of exposing patients to high concentrations of drugs. In this study, hybrid nanocomposites were developed to address this issue by combining poly(vinyl alcohol) and κ-carrageenan with whitlockite nanoapatite (WNA) particles and ciprofloxacin, aiming to achieve rapid hemostasis and sustained antibacterial effects. A physically cross-linked cryogel was obtained by subjecting a blend of poly(vinyl alcohol) and κ-carrageenan to successive freezing-thawing cycles, followed by the addition of WNA. Furthermore, ciprofloxacin was introduced into the cryogel matrix for subsequent evaluation of its wound healing properties. The resulting gel system exhibited a 3D microporous structure and demonstrated excellent swelling, low cytotoxicity, and outstanding mechanical properties. These characteristics were evaluated through analytical and rheological experiments. The nanocomposite cryogel with 4% whitlockite showed extended drug release of 71.21 ± 3.5% over 21 days and antibacterial activity with a considerable growth inhibition zone (4.19 ± 3.55 cm). Experiments on a rat model demonstrated a rapid hemostasis property of cryogels within an average of 83 ± 4 s and accelerated the process of wound healing with 96.34% contraction compared to the standard, which exhibited only ∼78% after 14 days. The histopathological analysis revealed that the process of epidermal re-epithelialization took around 14 days following the skin incision. The cryogel loaded with WNAs and ciprofloxacin holds great potential for strategic utilization in wound management applications as an effective material for hemostasis and anti-infection purposes.

NIR-activated electrospun nanodetonator dressing enhances infected diabetic wound healing with combined photothermal and nitric oxide-based gas therapy.

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane's PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague-Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds.

Polyvinyl alcohol addition to freezing extender can improve the post-thaw quality, longevity and in vitro fertility of ram epididymal spermatozoa.

Recovering and cryopreserving epididymal spermatozoa are suitable methods for preserving the genetic potential of livestock and endangered species. Regarding encouraging reports on the use of polyvinyl alcohol (PVA) in cryopreserving various cell types, we conducted this study to examine the impact of PVA on the post-thaw quality, longevity, and in vitro fertility of ram epididymal sperm. In the first experiment, ram epididymal spermatozoa were frozen in extenders containing 6 % glycerol and 0, 0.5, 1, 2, 5, 10, or 15 mg/ml of PVA. Polyvinyl alcohol at concentrations of 0.5, 1, and 2 mg/ml improved the motility and functional membrane integrity (FMI) of the sperm compared with the control group (P < 0.05). In the second experiment, we investigated whether PVA could partially substitute glycerol in the freezing extender. PVA was added at 0, 0.5, 1, and 2 mg/ml to the extenders containing 1 % or 2 % glycerol. After thawing, the sperm motility parameters of the group containing 1 mg/ml PVA and 2 % glycerol were significantly higher than those of the un-supplemented groups (P < 0.05). In the third experiment, the effect of PVA on the post-thaw sperm longevity were examined. Sperm were frozen in 3 extenders: one containing 6 % glycerol and 1 mg/ml PVA (Gly6P1), another containing 2 % glycerol and 1 mg/ml PVA (Gly2P1), and a control extender with 6 % glycerol. After thawing, the quality of the sperm was evaluated. Sperm were then diluted in human tubal fluid (HTF) and incubated at 37 °C for 3 h. Afterwards, the quality of the sperm was evaluated once more. The presence of PVA in the freezing extender improved motility parameters and FMI. Additionally, PVA-containing groups had lower proportions of capacitated and acrosome reacted sperm compared with the control group (P < 0.05). The Gly6P1 group performed better than the other two groups (P < 0.05). In the fourth experiment, sperm from the Gly6P1 and Control groups were used in the IVF process immediately after thawing (T0) and after a 3-h incubation at 37 °C in HTF (T3). Cleavage, blastocyst and hatching rates in both groups were similar at T0, but they were lower in the Control group at T3 (P < 0.05). In conclusion, PVA as an additive to the freezing extender significantly improves post-thaw motility, viability, acrosome integrity, longevity, and fertile lifespan of ram epididymal spermatozoa.

Water-Induced Expanded Bilayer Vascular Graft with Good Hemocompatibility and Biocompatibility.

Shape memory polymer (SMP) vascular grafts are promising interventional vascular grafts for cardiovascular disease (CAD) treatment; However, hemocompatibility and biocompatibility, which are the critical issues for the SMP vascular grafts, are not systematically concerned. Furthermore, the water-induced SMP grafts are more convenient and safer than the thermally induced ones in case of the bioapplication. Herein, in this work, the new water-induced expanded bilayer vascular graft with the inner layer of crosslinked poly(ε-caprolactone) (cPCL) and the outer layer of water-induced SMP of regenerated chitosan/polyvinyl alcohol (RCS/PVA) are prepared by hot pressing and programming approaches. The results show that the inner and outer layer surfaces of the prepared grafts are smooth, and they exhibit good interfacial interaction properties. The bilayer grafts show good mechanical properties and can be expanded in water with a diameter expansion of ≈30%. When compared with commercial expanded polytetrafluoroethylene (ePTFE), the bilayer graft shows better hemocompatibility (platelet adhesion, hemolysis rate, various clotting times, and plasma recalcification time (PRT)) and in vitro and in vivo biocompatibility, which thus is a promising material for the vascular graft.

Temporal Changes in the Surface Chemistry and Topography of Reactive Ion Plasma-Treated Poly(vinyl alcohol) Alter Endothelialization Potential.

Synthetic small-diameter vascular grafts (<6 mm) are used in the treatment of cardiovascular diseases, including coronary artery disease, but fail much more readily than similar grafts made from autologous vascular tissue. A promising approach to improve the patency rates of synthetic vascular grafts is to promote the adhesion of endothelial cells to the luminal surface of the graft. In this study, we characterized the surface chemical and topographic changes imparted on poly(vinyl alcohol) (PVA), an emerging hydrogel vascular graft material, after exposure to various reactive ion plasma (RIP) surface treatments, how these changes dissipate after storage in a sealed environment at standard temperature and pressure, and the effect of these changes on the adhesion of endothelial colony-forming cells (ECFCs). We showed that RIP treatments including O2, N2, or Ar at two radiofrequency powers, 50 and 100 W, improved ECFC adhesion compared to untreated PVA and to different degrees for each RIP treatment, but that the topographic and chemical changes responsible for the increased cell affinity dissipate in samples treated and allowed to age for 230 days. We characterized the effect of aging on RIP-treated PVA using an assay to quantify ECFCs on RIP-treated PVA 48 h after seeding, atomic force microscopy to probe surface topography, scanning electron microscopy to visualize surface modifications, and X-ray photoelectron spectroscopy to investigate surface chemistry. Our results show that after treatment at higher RF powers, the surface exhibits increased roughness and greater levels of charged nitrogen species across all precursor gases and that these surface modifications are beneficial for the attachment of ECFCs. This study is important for our understanding of the stability of surface modifications used to promote the adhesion of vascular cells such as ECFCs.

Sodium alginate/polyvinyl alcohol nanofibers loaded with Shikonin for diabetic wound healing: In vivo and in vitro evaluation.

Diabetic wounds are typically chronic wounds and the healing process is limited by problems such as high blood glucose levels, bacterial infections, and other issues that make wound healing difficult. Designing drug-loaded wound dressings is an effective way to promote diabetic wound healing. In this study, we developed an SA/PVA nanofiber (SPS) containing Shikonin (SK) for the treatment of diabetic wounds. The prepared nanofibers were uniform in diameter, had good hydrophilicity and high water vapor permeability, and effectively promoted gas exchange between the wound site and the outside world. The results of in vitro experiments showed that SPS was effective in antimicrobial, antioxidant, and biocompatible. In vivo tests showed that the wound healing rate of mice treated with SPS reached 85.5 %. Immunohistochemical staining results showed that SPS was involved in the diabetic wound healing process through the up-regulation of growth factors (CD31, HIF-1α) and the down-regulation of inflammatory factors (CD68). Western blotting experiments showed that SPS attenuated the inflammation through the inhibition of the IκBα/NF-κB signaling pathway. These results suggest that SPS is a promising candidate for future clinical application of chronic wound dressings.

Kartogenin-loaded polyvinyl alcohol/nano-hydroxyapatite composite hydrogel promotes tendon-bone healing in rabbits after anterior cruciate ligament reconstruction.

Accumulating evidence supports the role of cartilage tissue engineering in cartilage defect repair, but the biological function has yet to be fully explained. In this work, kartogenin (KGN), an emerging chondroinductive nonprotein small molecule, was incorporated into a composite hydrogel of polyvinyl alcohol/nano-hydroxyapatite (PVA/n-HA) to fabricate an appropriate microenvironment for tendon-bone healing after anterior cruciate ligament (ACL) reconstruction. KGN/PVA/n-HA composite hydrogel scaffolds were prepared by in situ synthesis and physical adsorption, followed by characterization under a scanning electron microscope. The scaffolds were transplanted into healthy New Zealand White (NZW) rabbits. It was confirmed that KGN/PVA/n-HA scaffolds were successfully prepared and exhibited good supporting properties and excellent biocompatibility. Unilateral ACL reconstruction was constructed with tendon autograft in NZW rabbits, and the morphology and diameter of collagen fiber were analyzed. The scaffolds were shown to promote ACL growth and collagen fiber formation. Furthermore, microcomputerized tomography analysis and bone formation histology were performed to detect new bone formation. KGN/PVA/n-HA scaffolds effectively alleviated cartilage damage and prevented the occurrence of osteoarthritis. Meanwhile, ligament-bone healing and bone formation were observed in the presence of KGN/PVA/n-HA scaffolds. In conclusion, these results suggest that the KGN/PVA/n-HA scaffolds can facilitate tendon-bone healing after ACL reconstruction and might be considered novel hydrogel biomaterials in cartilage tissue engineering.

Strong, tough, high-release, and antibacterial nanocellulose hydrogel for refrigerated chicken preservation.

Enormous amounts of food resources are annually wasted because of microbial contamination, highlighting the critical role of effective food packaging in preventing such losses. However, traditional food packaging faces several limitations, such as low mechanical strength, poor fatigue resistance, and low water retention. In this study, we aimed to prepare nanocellulose hydrogels with enhanced stretchability, fatigue resistance, high water retention, and antibacterial properties using soy hull nanocellulose (SHNC), polyvinyl alcohol (PVA), sodium alginate (SA), and tannic acid (TA) as raw materials. These hydrogels were applied in food packaging to extend the shelf life of refrigerated chicken. The structure and properties (e.g., mechanical, antibacterial, and barrier properties) of these hydrogels were characterized using different techniques. Fourier-transform infrared spectroscopy revealed the presence of hydrogen and ester bonds in the hydrogels, whereas scanning electron microscopy revealed the three-dimensional network structure of the hydrogels. Mechanical testing demonstrated that the SHNC/PVA/SA/TA-2 hydrogel exhibited excellent tensile properties (elongation = 160 %), viscoelasticity (storage modulus of 1000 Pa), and mechanical strength (compressive strength = 10 kPa; tensile strength = 0.35 MPa). Moreover, under weak acidic and alkaline conditions, the ester bonds of the hydrogel broke down with an increase in pH, improving its swelling and release properties. The SHNC/PVA/SA/TA-2 hydrogel displayed an equilibrium swelling ratio exceeding 300 %, with a release rate of >80 % for the bioactive substance TA. Notably, antibacterial testing showed that the SHNC/PVA/SA/TA-2 hydrogel effectively deactivated Staphylococcus aureus and Escherichia coli, prolonging the shelf life of refrigerated chicken to 10 d. Therefore, the SHNC/PVA/SA/TA hydrogels can be used in food packaging to extend the shelf life of refrigerated meat products. Their cost-effectiveness and simple preparation make them suitable for various applications in the food industry.

Metal-amplified sonodynamic therapy of Ti-based chitosan-polyvinyl alcohol hybrid hydrogel dressing against subcutaneous Staphylococcus aureus infection.

Ultrasound (US)-mediated sonodynamic therapy (SDT) has received extensive attention in pathogen elimination for non-invasiveness and high spatial and temporal accuracy. Considering that hydrogel can provide a healing-friendly environment for wounds, in this work, hybrid hydrogels are constructed by embedding Ag doped TiO2 nanoparticles in chitosan-polyvinyl alcohol hydrogels for enhanced sonodynamic antibacterial therapy. With metal silver doped, TiO2 nanoparticles sonosensitivity is improved to generate more reactive oxygen species (ROS), which endows hybrid hydrogels with high-efficient antibacterial properties. In vivo results show that hybrid hydrogel dressing can prevent infection and promote wound closure within 2 days. The healing ratio excess 95 % with no pus produced at the end of treatment. The therapeutic mechanism was identified that heterojunction formed in Ag doped TiO2 facilitates the separation of charge carriers under US irradiation, leading to elevating ROS generation. The generated ROS promote hybrid hydrogels sonodynamic antibacterial therapeutic efficacy to thoroughly eliminate pathogen via disrupting bacterial cell membrane integrity, decreasing membrane fluidity and increasing membrane permeability. Besides, biofilm formation could be effectively inhibited. This work developed a hybrid hydrogel with amplified SDT effect for wound healing, which is expected to provide inspiration of hybrid hydrogels design and Ti-based nanomaterials sonosensitivity enhancement.

Development of a tannic acid- and silicate ion-functionalized PVA-starch composite hydrogel for in situ skeletal muscle repairing.

The repair capacity of skeletal muscle is severely diminished in massive skeletal muscle injuries accompanied by inflammation, resulting in muscle function loss and scar tissue formation. In the current work, we developed a tannic acid (TA)- and silicate ion-functionalized tissue adhesive poly(vinyl alcohol) (PVA)-starch composite hydrogel, referred to as PSTS (PVA-starch-TA-SiO32-). It was formed based on the hydrogen bonding of TA to organic polymers, as well as silicate-TA ligand interaction. PSTS could be gelatinized in minutes at room temperature with crosslinked network formation, making it applicable for injection. Further investigations revealed that PSTS had skeletal muscle-comparable conductivity and modulus to act as a temporary platform for muscle repairing. Moreover, PSTS could release TA and silicate ions in situ to inhibit bacterial growth, induce vascularization, and reduce oxidation, paving the way to the possibility of creating a favorable microenvironment for skeletal muscle regeneration and tissue fibrosis control. The in vivo model confirmed that PSTS could enhance muscle fiber regeneration and myotube formation, as well as reduce infection and inflammation risk. These findings thereby implied the great potential of PSTS in the treatment of formidable skeletal muscle injuries.

Antimicrobial effect of two fluoride-releasing adhesive tapes on Streptococcus mutans biofilm.

Fluoride-releasing adhesive tapes have been developed as a new fluoride delivery agent. However, application as caries prevention agents remains underexplored. This study aimed at evaluating the antimicrobial activity of two fluoride-releasing adhesive tapes against S. mutans biofilm. Two polyvinyl alcohol (PVA) tapes were investigated: (i) a fluoride-PVA (F-PVA) tape, (ii) a pullulan incorporated F-PVA (PF-PVA) tape. S. mutan strains were cultured and treated with the tapes. Antimicrobial effects were evaluated using the agar diffusion test, field-emission scanning electron microscopy (FE-SEM), and confocal laser scanning microscopy (CLSM). F-PVA tapes showed higher inhibition-zone diameters than PF-PVA at 48 h and 72 h. However, there were no significant differences (p > 0.05) between the effects of F-PVA and PF-PVA. The bio-volume of S. mutans and extracellular polymeric substances significantly decreased in the F-PVA tapes than in the PF-PVA tapes (p < 0.05). FE-SEM micrographs revealed less S. mutans colonization in F-PVA. F-PVA exhibited better antimicrobial activity against S. mutans than PF-PVA.

Construction of organ of Corti organoid to study the effects of berberine sulfate on damaged auditory cells.

Sensorineural hearing loss (SNHL) is mainly caused by injury or loss of hair cells (HCs) and associated spiral ganglion neurons (SGNs) in the inner ear. At present, there is still no effective treatment for SNHL in clinic. Recently, advances in organoid bring a promising prospect for research and treatment of SNHL. Meanwhile, three-dimensional (3D) printing provides a tremendous opportunity to construct versatile organoids for tissue engineering and regenerative medicine. In this study, gelatin (Gel), sodium alginate (SA), and polyvinyl alcohol (PVA) were used to fabricate biomimetic scaffold through 3D printing. The organ of Corti derived from neonatal mice inner ear was seeded on the PVA/Gel/SA scaffold to construct organ of Corti organoid. Then, the organ of Corti organoid was used to study the potential protective effects of berberine sulfate on neomycin-juried auditory HCs and SGNs. The results showed that the PVA/Gel/SA biomimetic 3D scaffolds had good cytocompatibilities and mechanical properties. The constructed organoid could maintain organ of Corti activity well in vitro. In addition, the injury intervention results showed that berberine sulfate could significantly inhibit neomycin-induced HC and SGN damage. This study suggests that the fabricated organoid is highly biomimetic to the organ of Corti, which may provide an effective model for drug development, cell and gene therapy for SNHL.

Silver-loaded poly(vinyl alcohol)/polycaprolactone polymer scaffold as a biocompatible antibacterial system.

A chronic nonhealing wound poses a significant risk for infection and subsequent health complications, potentially endangering the patient's well-being. Therefore, effective wound dressings must meet several crucial criteria, including: (1) eliminating bacterial pathogen growth within the wound, (2) forming a barrier against airborne microbes, (3) promoting cell proliferation, (4) facilitating tissue repair. In this study, we synthesized 8 ± 3 nm Ag NP with maleic acid and incorporated them into an electrospun polycaprolactone (PCL) matrix with 1.6 and 3.4 µm fiber sizes. The Ag NPs were anchored to the matrix via electrospraying water-soluble poly(vinyl) alcohol (PVA), reducing the average sphere size from 750 to 610 nm in the presence of Ag NPs. Increasing the electrospraying time of Ag NP-treated PVA spheres demonstrated a more pronounced antibacterial effect. The resultant silver-based material exhibited 100% inhibition of gram-negative Escherichia coli and gram-positive Staphylococcus aureus growth within 6 h while showing non-cytotoxic effects on the Vero cell line. We mainly discuss the preparation method aspects of the membrane, its antibacterial properties, and cytotoxicity, suggesting that combining these processes holds promise for various medical applications.

Promoting the healing of infected diabetic wound by nanozyme-containing hydrogel with anti-bacterial inflammation suppressing, ROS-scavenging and oxygen-generating properties.

Bacterial infections already pose a significant threat to skin wounds, especially in diabetic patients who have difficulty healing wounds. However, wound or bacterial infections are known to produce excess reactive oxygen species (ROS), and hypoxia may further hinder wound healing and the development of chronic wounds. In this study, a multifunctional hydrogel for ROS scavenging and bacterial inhibition was developed by cross-linking polyvinyl alcohol (PVA) and sodium alginate (SA) with graphene oxide (GO) loaded with silver-platinum hybrid nanoparticles (GO@Ag-Pt). The PVA/SA hydrogel loaded with GO@Ag-Pt exhibited the ability to scavenge different types of ROS, generate O2, and kill a broad spectrum of bacteria in vitro. The silver-platinum hybrid nanoparticles significantly increased the antibacterial ability against Escherichia coli and Staphylococcus aureus compared with silver nanoparticles (AgNps). GO@Ag-Pt loaded hydrogel was effective in treating infections caused by S.aureus, thereby significantly promoting wound healing during the inflammatory phase. Hydrogel therapy significantly reduced the level of ROS and alleviated inflammation levels. Notably, our ROS-scavenging, antibacterial hydrogels can be used to effectively treat various types of wounds, including difficult-to-heal diabetic wounds with bacterial infections. Thus, this study proposes an effective strategy for various chronic wound healing based on ROS clearance and bacteriostatic hydrogels.

Synthesis and characterization of chitosan-PVA hydrogel containing PEGylated recombinant epidermal growth factor on cell culture for wound healing substitute

Abstract The aim of the current study was to assess the physicochemical characteristics and wound healing activity of chitosan-polyvinyl alcohol (PVA) crosslinked hydrogel containing recombinant human epidermal growth factor (rh-EGF) or recombinant mouse epidermal growth factor (rm-EGF). The hydrogels were prepared and analyses were made of the morphological properties, viscosity, water absorption capacity, mechanical and bio-adhesive properties. The viscosity of the formulations varied between 14.400 - 48.500 cPs, with the greatest viscosity values determined in K2 formulation. F2 formulation showed the highest water absorption capacity. According to the studies of the mechanical properties, H2 formulation (0.153±0.018 N.mm) showed the greatest adhesiveness and E2 (0.245±0.001 mj/cm2) formulation, the highest bio-adhesion values. Hydrogels were cytocompatible considering in vitro cell viability values of over 76% on human keratinocyte cells (HaCaT, CVCL-0038) and of over 84% on human fibroblast cells (NIH 3T3, CRL-1658) used as a model cell line. According to the BrdU cell proliferation results, B1 (197.82±2.48%) formulation showed the greatest NIH 3T3 and C1 (167.43±5.89%) formulation exhibited the highest HaCaT cell proliferation ability. In addition, the scratch closure assay was performed to assess the wound healing efficiency of formulation and the results obtained in the study showed that F2 formulation including PEGylated rh-EGF had a highly effective role.

Viability of mesenchymal stem cells during electrospinning

Tissue engineering is a technique by which a live tissue can be re-constructed and one of its main goals is to associate cells with biomaterials. Electrospinning is a technique that facilitates the production of nanofibers and is commonly used to develop fibrous scaffolds to be used in tissue engineering. In the present study, a different approach for cell incorporation into fibrous scaffolds was tested. Mesenchymal stem cells were extracted from the wall of the umbilical cord and mononuclear cells from umbilical cord blood. Cells were re-suspended in a 10 percent polyvinyl alcohol solution and subjected to electrospinning for 30 min under a voltage of 21 kV. Cell viability was assessed before and after the procedure by exclusion of dead cells using trypan blue staining. Fiber diameter was observed by scanning electron microscopy and the presence of cells within the scaffolds was analyzed by confocal laser scanning microscopy. After electrospinning, the viability of mesenchymal stem cells was reduced from 88 to 19.6 percent and the viability of mononuclear cells from 99 to 8.38 percent. The loss of viability was possibly due to the high viscosity of the polymer solution, which reduced the access to nutrients associated with electric and mechanical stress during electrospinning. These results suggest that the incorporation of cells during fiber formation by electrospinning is a viable process that needs more investigation in order to find ways to protect cells from damage.

Effect of renal embolization with trisacryl and PAVc

OBJECTIVES: Evaluate the degree of vascular occlusion, vascular recanalization, and necrosis of the vascular wall caused by polyvinyl alcohol-covered polyvinyl acetate (PVAc) particles compared to trisacryl particles after renal embolization. METHODS: Seventy-nine female albino New Zealand rabbits underwent arterial catheterization of the right kidney. Thirty-three animals were embolized with trisacryl particles, thirty-one with PVAc particles, and fifteen were kept as controls. Four animals were excluded (three trisacryl and one PVAc) due to early death. Five subgroups of six animals were created. The animals in the different groups were sacrificed either 48 hours, 5 days, 10 days, 30 days, or 90 days after embolization. The control group was divided into subgroups of three animals each and kept for the same periods of time. The kidneys were dyed with hematoxylin-eosin and Masson's trichrome and then examined using optical microscopy. RESULTS: There were significant differences in the degree of vascular occlusion caused by the trisacryl and the PVAc particles between the five-day and the ten-day groups. Additional differences were noted between the five-day and 48-hour groups in regard to the amount of necrosis. For both findings, the PVAc group members showed adequate tissue reaction (ischemia and volumetric reduction) and less recanalization than those treated with trisacryl. CONCLUSION: The use of PVAc as an embolization material exhibited an adequate tissue reaction (ischemia and volumetric reduction), more expressive vascular occlusion and necrosis, and less recanalization than the trisacryl material.

Evaluation of polyvinyl alcohol for fatty acid supplementation in adipose tissue explant culture

Cultures of adipose tissue explants are a valuable tool for studying the intracellular mechanisms involving hormones and nutrients. However, testing how fatty acids affect cells requires a carrier molecule; bovine serum albumin (BSA) has been used for this purpose. However, contaminants can alter the cellular response. Our objectives were to: 1) test BSA as a fatty acid carrier and 2) evaluate polyvinyl alcohol (PVA) as a replacement for BSA. Adipose tissue explants from nine pigs were cultured in medium 199 for 4, 12, 24, and 48 h, with the following treatments: control, PVA (100 mM PVA added) and PVA + pGH (100 mM PVA plus 0.1 mg/mL porcine growth hormone). After each culture period, explants were collected and assayed for lipogenesis. After 48 h in culture, explants were assayed for lipolysis. A preliminary study with different commercial sources and high concentrations showed that BSA affected lipogenic rates. On the other hand, there were no effects of PVA on lipid synthesis, while pGH (positive control) reduced glucose incorporation into lipids (P < 0.01) when compared to both control and PVA (P < 0.05). There was no difference between control and PVA for lipolysis rates. However, pGH increased lipolysis when compared to control (P < 0.01) and PVA (P < 0.05). We demonstrated that BSA can alter lipogenesis, which precludes its use as a carrier molecule. On the other hand, addition of PVA had no effect on lipolysis or lipogenesis. We suggest the use of PVA instead of BSA for adding bioactive fatty acids to cultures of adipose tissue

The use of filter paper plasticized with polyvinyl alcohol-glutaraldehyde in ELISA

F1-antigen purified from Yersinia pestis was covalently linked to 5-mm diameter filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde. These discs were used both for ELISA and dot-ELISA for the detection of anti-F1 IgG in rabbits. The best conditions were achieved using 1.25 µg of F1 antigen/disc, 3 percent w/v skim milk in PBS as blocking agent, anti-IgG peroxidase conjugate diluted 12,000 times, and serum from rabbits immunized or not against Y. pestis, diluted 6,400 times. The absorbance values obtained from the comparative study between this procedure and conventional ELISA were not significantly different but the low cost of the reagents employed in ELISA using the filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde makes this method economically attractive.