Predatory bacterial hydrogels for topical treatment of infected wounds

Wound infection is becoming a considerable healthcare crisis due to the abuse of antibiotics and the substantial production of multidrug-resistant bacteria. Seawater immersion wounds usually become a mortal trouble because of the infection of Vibrio vulnificus. Bdellovibrio bacteriovorus, one kind of natural predatory bacteria, is recognized as a promising biological therapy against intractable bacteria. Here, we prepared a B. bacteriovorus-loaded polyvinyl alcohol/alginate hydrogel for the topical treatment of the seawater immersion wounds infected by V. vulnificus. The B. bacteriovorus-loaded hydrogel (BG) owned highly microporous structures with the mean pore size of 90 μm, improving the rapid release of B. bacteriovorus from BG when contacting the aqueous surroundings. BG showed high biosafety with no L929 cell toxicity or hemolysis. More importantly, BG exhibited excellent in vitro anti-V. vulnificus effect. The highly effective infected wound treatment effect of BG was evaluated on mouse models, revealing significant reduction of local V. vulnificus, accelerated wound contraction, and alleviated inflammation. Besides the high bacterial inhibition of BG, BG remarkably reduced inflammatory response, promoted collagen deposition, neovascularization and re-epithelization, contributing to wound healing. BG is a promising topical biological formulation against infected wounds.

Preparation and physicochemical properties of PVA/HA composite microspheres for embolization / 国际生物医学工程杂志

Objective:To prepare polyvinyl alcohol (PVA) and hydroxyapatite (HA) composite embolization microspheres and investigate their physicochemical properties.Methods:PVA/HA composite embolization microspheres were prepared by reverse suspension polymerization, using PVA and HA as dispersed phases, liquid paraffin containing sorbitan fatty acid ester as the continuous phase, and glutaraldehyde as the cross-linking agent. The morphology, particle size distribution, and microscopic morphology of PVA/HA composite embolization microspheres were observed by optical microscopy and scanning electron microscopy. The chemical structure of PVA/HA composite embolization microspheres and the elasticity, drug loading, and drug release properties of PVA/HA composite bolus microspheres were characterized by Fourier infrared spectroscopy.Results:The PVA/HA composite embolization microspheres were internal, porous round spheres with a particle size distribution of 50-300 μm. The elastic properties of PVA/HA composite embolization microspheres were(13.6±0.145) kPa, which was 2.28 times that of PVA microspheres, and the drug loading capacity and encapsulation efficiency were (76.80±1.22) mg/g and (38.4±12.7)%, respectively. The maximum cumulative release rate of the microspheres within 7 days was (7.37±0.101)%, and the maximum cumulative release was (256.2±9.8) μg.Conclusions:PVA/HA composite embolization microspheres have good mechanical properties and drug-loading and drug-releasing properties, which provide an important reference for their use as medical devices.

Carvacrol-loaded polyvinyl alcohol/montmorillonite clay nanocomposite (PVA/MONT/Carva) as an antimicrobial agent for wound dressing

Aims@#This research was conducted to develop and characterize polyvinyl alcohol (PVA)/montmorillonite (MONT) clay incorporated with carvacrol (Carva) nanocomposite film as a potential material in wound dressing.@*Methodology and results@#Organophilic MONT clay, which was initially modified from commercial MONT clay by cetyltrimethylammonium bromide (CTAB), was used in the polymerization process using PVA. The synthesized nanocomposites were visualized via transmission electron microscopy (TEM). The developed film (PVA/MONT/Carva nanocomposite film) was characterized via Fourier transform infrared (FTIR). The investigation on mechanical property and antimicrobial activity of the film was also performed. All nanocomposites are spherical, with a size of 92.8 ± 22.1 nm. The -OH stretch, C-H stretch, aromatic group, SiO stretch, and C-O from acetyl group were identified in the PVA/MONT/Carva nanocomposite films. During the chemical release test, carvacrol attained a plateau at 24 h, with a total release of 62.3%. This nanocomposite exhibited a severe detrimental influence on the growth of Gram-bacteria and yeasts, which represented a broad spectrum of antimicrobial agents. All test microorganisms showed approximately up to 82% reduction of microbial growth during the Hohenstein challenge test. Physically, the nanocomposite films were yellowish and apparent. The film was sturdy, flexible, elastic and consisted of excellent water holding capacity.@*Conclusion, significance and impact of study@#PVA/MONT/Carva nanocomposite film may have a useful potential to be merged in the pharmaceutical application, especially in wound dressing production.

Effect of cell sheet combined with 3D printing an antler powder/silk fibroin/polyvinyl alcohol scaffold on the repair of mandibular defects in sheep / 口腔疾病防治

Objective @#To explore the feasibility of antler powder/silk fibroin/polyvinyl alcohol scaffolds as tissue engineering bone scaffolds and the relationship between their degradation performance and the healing speed of bone defects.@*Methods @# Antler powder/silk fibroin/polyvinyl alcohol scaffolds and nano hydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds were prepared by 3D printing. The whole bone marrow culture method was used to prepare blood cell sheets of Altay big tail sheep’s iliac bone marrow. With observation times of 1, 2 and 3 months, the mandibular defects of 4 sheep were established. The experimental group was coated with antler powder/silk fibroin/polyvinyl alcohol scaffolds. The control group was coated with nanohydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds. The negative control group was coated with gel-free sponges. According to the self-control method of the bilateral mandible defect area, scaffolds wrapped with cell membranes or gel sponges wrapped with cell membranes were implanted. At the ends of the first, second and third months after implantation, the experimental animals were killed, cone beam CT was performed, and paraffin sections were taken for HE staining to evaluate the effect of different scaffold materials on bone regeneration and scaffold degradation.@* Results@# Scanning electron microscopy showed that both groups had regular pores and good continuity, and there was no difference in pore size and porosity between the two groups (P > 0.05). The results of CBCT imaging showed that in 3 months after operation, the experimental group had significantly better repair effects on bone defects than the control group, and the degradation rate matched the bone repair rate. The bone mineral density in the center of the defect was higher than that of the control group, which was close to that of normal bone tissue. The central bone mineral density of the experimental group at each time point was higher than those of the control group and the negative control group, and the difference was statistically significant (P < 0.05). HE staining results showed that the bone cells in the experimental group were more active, with more new capillaries and bone trabeculae formed, and the scaffold material absorbed more than the control group. @*Conclusion @#The antler powder/silk fibroin/polyvinyl alcohol scaffold can promote the repair of critical bone defects. Its degradability matches its bone tissue healing rate. It is expected to become a promising scaffold material for bone tissue engineering.

Research status of 3D⁃printed composite PVA bone tissue engineering scaffolds / 口腔疾病防治

@# Three dimensionally printed composite porous bone tissue engineering scaffolds have become a research focus. Composite polyvinyl alcohol (PVA) has good biocompatibilityand degradability, but it cannot be prepared indepen⁃dently because it cannot resist highmechanical resistance. This material shows many advantages, such as good biocom⁃patibility, degradability and mechanical properties, when compounded with other materials with good mechanical proper⁃ties and good biocompatibility. Therefore, 3D printed composite PVA scaffold material can optimize the performance of PVA scaffolds. This article reviews 3D printing bone scaffold technology, polyvinyl alcohol (PVA), and composite PVA scaffolds for in vivo and in vitro bone formation.

Treating recurrent aphthous stomatitis with oral mucoadhesive films containing chitosan: a clinical random⁃ized controlled study / 口腔疾病防治

Objective@#To study the efficacy and safety of oral mucoadhesive containing chitosan for the treatment of recurrent aphothous stomatitis (RAS)@* Methods@#72 subjects, who were diagnosed with RAS, were involved in the study. The subjects were randomly allocated to the test or control group and shown how to use the films. The film con⁃taining chitosan was provided to the participants in the test group and the polyvinyl alcohol film was provided to the con⁃trol group. Baseline, pain score (visual analog scale), ulcer size and adverse effects were recorded@* Results @#The reduc⁃tion in ulcer size was significantly greater (P < 0.05) in the treatment group (2.91 ± 3.66)mm 2 than in the control group (1.10 ± 2.26) mm 2 between days 4 and 6. There was no significant difference between the treatment and control groups in the pain score, ulcer size, or reduction in the pain score (P > 0.05). No obvious adverse effects were observed.@* Con⁃clusion @#The oral mucoadhesive film containing chitosan promotes healing of RAS.

Films Based on Blends of Polyvinyl Alcohol and Microbial Hyaluronic Acid

Abstract The aims of this work were to produce hyaluronic acid (HA) by Streptococcus zooepidemicus ATCC 39920 in a low cost sugarcane molasses fermentation medium and to employ the produced HA to obtain films blends based on polyvinyl alcohol (PVA). The films were produced using solution casting method and they were characterized according to their microstructure, mechanical and barrier properties. HA was added in different concentrations (0, 5, 10 and 15% (w/w)), and glycerol was used as a plasticizer (25 g/100 g solids). All formulations resulted in easily manipulated films with good appearance. The addition of HA on PVA films increased their thermal stability, solubility, swelling index, water vapor permeability and elongation. Microbial HA sample combined with PVA showed to be a promising material to biomedical application, and an addition between 5 and 10% (w/w) was sufficient to improve PVA films properties.

Optical properties of polyvinyl alcohol membrane with n-HAp for bio-medical applications

Composite membrane as a flexible materials have found diverse applications in industrial and biomedical simultaneously, the recent studies have shown intrinsic improvement for membrane properties by inclusion of nanoparticles as a fillers with high portion ratio in inorganic polymers, the combination between two parts polymer and filler is as a result of collection the advantage of two component systems parts together. In this work, samples of polyvinyl alcohol (PVA)-nanoHaydroxyapatite (nHAp) composites were prepared by using casting method. The effects of addition of (nHAp) with different concentration on the optical properties of (PVA- nHAp) composite membrane have been studied by using wavelength range (220-820) nm. The absorption spectra, transmittance spectra, absorption coefficient, energy gap, refractive index, optical conductivity and extinction coefficient have been determined. The results show that the optical constants change with the increase of nHPA concentrations.

Comparison of the efficacy of partial splenic embolization with different sizes of polyvinyl alcohol / 实用放射学杂志

Objective To compare the efficacy of partial splenic embolization (PSE)with 150－350 μm and 350－560 μm polyvinyl alcohol (PVA).Methods A total of 24 patients were analyzed retrospectively in this study.Among them,9 patients underwent PSE with PVA of 1 50－350 μm (group A)and 1 5 patients with PVA of 350－560 μm (group B).Hematological parameters including white blood cell and platelet counts before and 1 week after surgery were compared between the two groups,as well as postoperative complications. Results The white blood cell and platelet counts were both significantly increased after 1 week of surgery compared with that before surgery (both P＜0.05).Furthermore,group A had obvious advantage over group B in increasing platelets (P＝0.05).The incidences of postoperative complications were 100% (9/9)in group A and 87% (13/15)in group B,respectively,but the incidence and severity of complications between two groups were comparable.Conclusion PSE with PVA of 1 50－3 50 μm has advantage in postoperative platelet improvement over PVA of 350－560 μm.

A Noval Method for Producing Antibacterial Wound Dressing by Using Fused Deposition Molding with Post-3D-printed Process / 中国医疗器械杂志

Using three-dimensional printing to produce antibacterial wound dressing is a new topic that will change the production style of wound dressing industry. Combining with post-3D-printed process, a desktop fused deposition molding equipment can be used to produce wound dressing containing polyvinyl alcohol, alginate and chitosan. The wound dressing produced by FDM has good aspects of absorbency, moisture vapour transmission rate and mechanical property. After loaded with antibacterial agent iodine and silver nano particle, the antibacterial activity rate increases to 99% and it is suitable to use as antibacterial wound dressing. This method affects the production of wound dressing to a more cost-effective way, and provides a possible individualized treatment for patient in the future.

A study of polyvinyl alcohol hydrogel simulating human vitreous body / 眼科新进展

Objective To screen a kind of polyvinyl alcohol (PVA) hydrogel with similar physical properties to human vitreous body as to provide basis for exploring new vitreous substitutes.Methods Different concentrations (1％,3％,7％) PVA solution were crosslinked by γ-irradiation (Co60),and 1％,3％ and 7％ PVA hydrogels were harvested.Then PVA hydrogels with similar properties to natural vitreous were screened by detecting the physical and optical properties (density,water content,light transmittance,refractive index,pH value,swelling property) and rheological properties and cytotoxicity of PVA hydrogels.Results As for the physical and optical properties of the hydrogels,the water content,refractive index,light transmittance,pH value and density of 1％,3％ and 7％ PVA hydrogel was 98.90％ vs.98.10％ vs.93.50％,1.335 5 vs.1.336 1 vs.1.342 5,94.80％ vs.93.20％ vs.88.20％,7.22 vs.7.25 vs.7.41 and 1003.9 g · L-1d vs.1014.4 g · L-1 vs.1114.7 g · L-1,respectively.Finally,1％ and 3％PVA hydrogels had the similar physical and optical properties to the human vitreous.As for rheological properties,the storage modulus (G') of the three PVA hydrogels was larger than the loss modulus (G"),indicating that these three hydrogels were viscoelastic gel,and the elastic properties was greater than the viscosity.1％ PVA:G'was (3.2 ±1.1)Pa,G" was (0.8 ±0.5)Pa;3％ PVA:G'was (6.1 ± 1.3)Pa,G" was (1.3 ±0.9)Pa;7％ PVA:G'was (106.5 ± 18.6) Pa and G" was (18.3 ± 12.8) Pa.According to resilience,the hydrogels can be ranked as follows:7％ PVA ＞ 3％ PVA ＞ 1％ PVA;in terms of creep,3％ PVA ＞ 7％ PVA ＞ 1％ PVA.Additionally,MTT colorimetric assay showed that there was no significant difference in A values among the three groups by cells culture in 1％,3％ and 7％ PVA for 72 hours (all P ＞0.05),suggesting that all the three hydrogels showed no obvious cytotoxicity and had good biocompatibility.Conelusion 3％ PVA hydrogel has similar optical,physical and rheological properties to the human vitreous,and shows good biocompatibility,which can be one of vitreous substitutes.

Research Progress of Polyvinyl Alcohol (PVA) Based on Hydrogel Dressings / 中国医疗器械杂志

This review introduces a brief description on the featured properties of polyvinyl alcohol based on hydrogel dressings. During past ten years many new artificial polymeric dressings have been developed, which meet requirements of wound healing. This review mainly focuses on one representative of ideal polymeric wound dressing membranes, polyvinyl alcohol based hydrogel dressings. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite hydrogel membranes to achieve the ideal wound dressing requirements.

Clinical effect observation of pranoprofen combined with deproteinized calf blood extract eye drops for moderate to severe dry eye / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To explore clinical effect of pranoprofen combined with deproteinized calf blood extract eye drops for moderate to severe dry eye. ·METHODS: A total of 84 patients (132 eyes) who received treatment at the Zhengzhou Second Hospital were selected from January 2016 to January 2017. According to random number table method they were divided into control group 42 cases (68 eyes) and observation group 42 cases (64 eyes), the control group using polyvinyl alcohol eye drops with pranoprofen, observation group with pranoprofen with deproteinized extract of calf blood eye drops. Subjective and objective scores before and after treatment were recorded. · RESULTS: There was no statistically significant difference on the four objective indicators of pretreatment FL,BUT,SⅠt,and vision between the two groups (P>0.05). Dry eye symptom scores of the two groups decreased after treatment,both with significantly different (P<0.05);after treatment,the symptom scores of the observation group were significantly lower than those in the control group, and the difference was statistically significant (P< 0. 05), indicating that the subjective symptoms of the observation group were better than that of the control group after treatment. After treatment of the control group and the observation group,the FL index was significantly lower than before treatment, BUT, S Ⅰ t and vision were significantly higher than before treatment, and the differences within either group were statistically significant(P<0.05);those indexes of observation group were different compared with control group (P < 0. 05), indicating that the objective symptoms of the observation group were better than that of the control group after treatment. None of the patients showed serious adverse reactions. ·CONCLUSION: The clinical effect of praprofen on the treatment of moderate to severe dry eye with the deproteinized calf blood extract is better.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate

Abstract Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30 °C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability.

A comparative study on the fertility of uterine artery embolization and myomectomy for leiomyoma / Монголын Анагаах Ухаан

Objective@#To compare the nature of pregnancy and deliveryin women with leiomyoma who were treated with uterine artery embolization to the outcomes in women who were treated with abdominal myomectomy. @*Material and Methods@#A prospective, clinical study was conducted in 2010-2013 at “Urguu” Maternity Hospital, Ulaanbaatar. 94 women meeting the criteria were selected for the study. Post-treatment, the patients were reviewed for a period of two years. Uterine artery embolization was performed using polyvinyl alcohol particles (300-500 µm in diameter).@*Results@#The percentage of conception in UAE group was 25.5% and 31.9% in myomectomy group (p=0.494); complication of pregnancy was 50.0% and 57.1% respectively (p=0.729); complication of delivery was 33.3% and 0.0% respectively (p=0.047). 88.9% and 90.0% (p=0.596) had Caesarean delivery. 16 (84.2%) women had uncomplicated and 3 (15.8%) women had complicated delivery due to placenta praevia, placenta acreta and uterine hypotonia. These cases all belonged to UAE group. @*Conclusion@#Pregnancy rates in women with leiomyoma who were treated by uterine artery embolization, compared with pregnancies after abdominal myomectomy, were similar.(p=0.494) In this study, there was the rate of Cesarean delivery above 80 percent in both group. There were no differences in newborn weights and Apgar scores.

Transcatheter arterial sclerosing embolization combined Propranolol for treatment of huge hemangioma in infants / 中国介入影像与治疗学

Objective To evaluate the therapeutic effects and safety of transcatheter arterial sclerosing embolization (TASE) combined with oral Propranolol in infantile huge hemangiomas.Methods A total of 76 infants with huge hemangioma were treated by TASE.All patients received oral Propranolol based on their weight.The follow-up and efficacy evaluation were performed from the last treatment.And the complications were analyzed.Results Seventy-six cases underwent 95 case-times of TASE totally.The success rate of puncture technique was 100％ (95/95).All patients were divided into 5 levels (0-Ⅳ levels) based on the curative effect of the follow-up,including 6 cases (6/76,7.90％) of level Ⅰ,19 cases (19/76,25.00％) of level Ⅱ,23 cases (23/76,30.26％) of level l,and 28 cases (28/76,36.84％) of level Ⅳ.The total effective rate was 100％ (76/76).There was no serious complications,and the curative effect was stable during the follow-up.Conclusion TASE combined with oral Propranolol in infantile huge hemangiomas is effective with less invasiveness and fewer complications.

Transcatheter arterial sclerosing embolization combined Propranolol for treatment of huge hemangioma in infants / 中国介入影像与治疗学

Objective To evaluate the therapeutic effects and safety of transcatheter arterial sclerosing embolization (TASE) combined with oral Propranolol in infantile huge hemangiomas.Methods A total of 76 infants with huge hemangioma were treated by TASE.All patients received oral Propranolol based on their weight.The follow-up and efficacy evaluation were performed from the last treatment.And the complications were analyzed.Results Seventy-six cases underwent 95 case-times of TASE totally.The success rate of puncture technique was 100％ (95/95).All patients were divided into 5 levels (0-Ⅳ levels) based on the curative effect of the follow-up,including 6 cases (6/76,7.90％) of level Ⅰ,19 cases (19/76,25.00％) of level Ⅱ,23 cases (23/76,30.26％) of level l,and 28 cases (28/76,36.84％) of level Ⅳ.The total effective rate was 100％ (76/76).There was no serious complications,and the curative effect was stable during the follow-up.Conclusion TASE combined with oral Propranolol in infantile huge hemangiomas is effective with less invasiveness and fewer complications.

Preparation of new type polyvinyl alcohol-porphyrin nanoparticles and its photothermal properties / 重庆医学

Objective To analyze the physicochemical properties and photothermal properties after introducing a certain proportion of phaeophorbide into polyvinyl alcohol-lipoic acid polymer.Methods The "one-step" method was adopted to synthesize the PVA27K-4 ％LA-10 ％ Pheide (PLP) polymer.The laser particle diameter tester was used to detect the particle size,polydispersity index and ζ potential of PLP nanoparticle (PLPN);the morphology was observed under transmission electron microscope (TEM);the in vitro fluorescent and photothermal properties were investigated by using spectrophotometric method and infrared thermal imager;the ovarian-cancer nude mice models were established and the preliminary in vivo experiment evaluation was performed.Results The synthetic PLP polymer could self-assembly form spherical PLPN in aqueous environment,which showed the tightly spherical structure under TEM.The average particle diameter,polydispersity index and ζ potential were (22.92 ± 9.00)nm,(0.117±0.056) and (-25.43±0.77)mV respectively.The fluorescence intensity of PLPN in PBS solution was significantly lower than that in SDS solution (P＜0.05).However,the temperature of the PBS solution of PLPN was significantly higher than that of the SDS solution after exposure to the near infrared light (P＜0.05).In the model of tumor-bearing nude mice,PLPN could targetaccumulated in the tumor site.The temperature in the tumor site was significantly increased after exposure to the near infrared light,which could kill tumor cells.Conclusion PLPN could emit red fluorescence,and could target-accumulated in tumor site and conduct the in vivo image,which has significant photothermal conversion properties in vivo and in vitro,and can effectively inhibit the tumor growth in vivo.

Study on formation process of vacuum negative pressure of micro power negative pressure technology / 医疗卫生装备

Objective To explore the formation process of vacuum pressure differential of micro power negative pressure technology to facilitate its clinical application.MethodsThe formation of negative pressure differential and changes of negative pressure values in enclosure space were studied which was formed by liquid aspiration after the compressive polyvinyl alcohol foam material was enclosed.Micro power negative pressure technology was applied to the treatment of the right ear necrosis patient after focal cleaning,and the efficacy was observed.Results Medical adhesive film was raised gradually during the expansion of polyvinyl alcohol foam due to liquid aspiration,and then the enclosure space extended increasingly to form local vacuum negative pressure.The range of maximal negative pressure was between-110 and-200 Pa,and the mean maximal negative pressure value was-132.7 Pa.Micro power negative pressure technology behaved well in healing the wound.Conclusion Micro power negative pressure technology gains advantages in reliability and easy operation over other technologies and products,and may be a new choice for healing of refractory wounds.

Optimization of Film-forming Materials for Compound Rhizoma Corydalis Plastics / 中国药师

Objective:To optimize the formula of film-forming materials for compound rhizoma corydalis plastics. Methods:Poly-vinyl alcohol 124 (PVA124) and bletilla striata gum were selected as the film-forming materials. The amounts of PVA 124, bletilla striata gum, glycerol and absolute ethanol were used as the influencing factors in an orthogonal test with the composite score of film-forming time and appearance as the indices to screen out the best composition of film-forming materials. Results:The best composition of film-forming materials was as follows:8 g PVA 124, 1 g bletilla striata gum, 2 ml glycerol and 15 ml ethanol. Conclusion:The op-timized film-forming materials can be used for the preparation of compound rhizoma corydalis plastics.