Histocompatibility of poly(L-lactide-co-ε-caprolactone)/cross-linked polyvinylpyrrolidone ureteral stent grafted into the rat bladder / 中国组织工程研究

BACKGROUND: With the development of tissue engineering, materials science, and biomechanics, developing new biodegradable ureteral stent has become an issue of concern. The ureteral stent with poly(L-lactide-co-ε-caprolactone)/crosslinked polypyrrolidone was prepared. OBJECTIVE: To explore the histocompatibility of the ureteral stent grafted into the bladder of Sprague-Dawley rats. METHODS: Sixty male Sprague-Dawley rats (provided by Laboratory Animal Center of Sichuan Academy of Traditional Chinese Medicine) were randomly divided into four groups, each group containing 15 rats. The sham operation group was directly sutured after opening a small incision on the outside of the bladder, and no material was implanted. The other three groups were implanted with polyurethane ureteral stent (control group), poly(L-lactide-co-ε-caprolactone)/8% cross-linked polyvinylpyrrolidone ureter stent (experiment group 1), poly(L-lactide ε- caprolactone)/5% cross-linked polyvinylpyrrolidone ureteral stent (experiment group 2) after opening a small incision on the outer side of the bladder, followed by suturing the incision. At 4, 8, and 16 weeks after operation, the local anatomy of the bladder was observed. The histocompatibility of the materials in each group was observed by hematoxylin-eosin staining. The study was approved by the Ethical Committee of Laboratory Animal Analysis and Testing Center of West China School of Public Health, Sichuan University. RESULTS AND CONCLUSION: (1) Gross observation: At 4, 8 and 16 weeks postoperatively, different degrees of chronic inflammation reaction occurred in the control group and experimental group 1. In the experiment group 2, chronic inflammatory reaction appeared at 4 weeks postoperatively. The stone formation rate in the control group and experimental group 1 was significantly higher than that in the sham operation group (P 0. 05). The calculus formation rate in the experimental group 2 was significantly higher than that in the sham operation group only at 4 weeks postoperatively, and had no significant difference at other time points (P > 0. 05). (2) Pathological observation: Different degrees of foreign body in the outer membrane, inflammatory reaction and diffuse hyperplasia of the mucosa were found in the control group, experimental groups 1 and 2 at different time points postoperatively. There was no significant difference in the rate of diffuse hyperplasia of the mucosa at different time points postoperatively among groups (P > 0. 05), but higher than that in the sham operation group (P < 0. 05). (3) These results indicate that the calculus formation rate and bladder histological reaction of poly(L-lactide-co-ε-caprolactone)/cross-linked polyvinylpyrrolidone ureter stent are comparable with those of commercial ureteral stents, especially the addition of 5% cross-linked polyvinylpyrrolidone has better histocompatibility.

A Case of Hydrophilic Polymer Embolism after TEVAR / 日本心臓血管外科学会雑誌

Hydrophilic polymer embolism (HPE) associated with endovascular therapy has steadily gained attention. We report a case of a 70-year-old man who had undergone one-debranched TEVAR. He had a history of distal arch replacement for dissecting aortic aneurysm 14 years earlier. Pseudoaneurysm at the proximal site of graft anastomosis was found on computed tomography (CT) angiogram during the follow-up. 1 debranching TEVAR was performed using the pull-through technique. Fourth days after the procedure, a skin rash appeared in the right lower extremity around the access site. Skin biopsy with pathological examination revealed HPE. We decided to observe a patient because there was no symptom of limb ischemia. Skin lesions improved and he was discharged on the 27th postoperative day. Hydrophilic polymers are widely used in the endovascular devices and there is an urgent need to better understand the complication of HPE.

Antioxidants in the control of microorganism contamination and phenol oxidation in Eugenia pyriformis / Antioxidantes no controle da contaminação microbiana e da oxidação fenólica em Eugenia pyriformis

Uvaia (Eugenia pyriformis) is a fruit tree of the Myrtaceae family. It has recalcitrant seeds of limited longevity, making seed propagation difficult. Micropropagation is an alternative method to obtain a large quantity of progeny plants in a short period of time, by using any part of the plant as explant. The high concentration of phenols associated with the chemical composition of the Myrtaceae, and the presence of microorganisms in the plant material or culture media, can make in vitro propagation difficult and/or impossible. The objective was to evaluate various concentrations of antioxidants affecting the control of microbial contamination and phenol oxidation in vitro in uvaia. A completely randomized design was used, with a 3 (antioxidants PVP, L-cysteine, and ascorbic acid) × 3 (antioxidant concentrations 100, 200, and 300 mg L-1) × 2 (activated charcoal at 0 and 2 g L-1) factorial arrangement + 2 additional variables (absence of antioxidants and activated charcoal; absence of antioxidants with 2 g L-1 activated charcoal), with three repetitions comprising four plants each. The percentage of bacterial and fungal contaminations, along with the number of oxidized explants, was evaluated after 7, 14 and 21 days of in vitro cultivation. It was concluded that, where bacterial and fungal contaminations were concerned, in vitro cultivation of uvaia can be performed without the use of antioxidants. PVP or ascorbic acid must, however be used in the process, at a concentration of 300 mg L-1, along with 2 g L-1 of activated charcoal. This helps to minimize phenol oxidation.

A uvaia Eugenia pyriformis é uma frutífera da família das mirtáceas cujas sementes apresentam longevidade curta e aspecto recalcitrante, fato que dificulta a propagação seminífera. A micropropagação surge como alternativa para obtenção de grande quantidade de mudas em curto período de tempo, por meio da utilização de qualquer parte da planta como explante. A elevada concentração de fenóis associados à composição química das mirtáceas e a presença de microrganismos no material vegetal ou no meio de cultura podem dificultar e/ou impossibilitar a propagação in vitro. Objetivou-se avaliar tipos e concentrações de antioxidantes no controle da contaminação microbiana e da oxidação fenólica in vitro de E. pyriformis. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 3 (antioxidantes ­ PVP, L-cisteína e ácido ascórbico) x 3 (concentrações - 100, 200 e 300 mg L-1) x 2 (carvão ativado ­ 0 e 2 g L-1) + 2 adicionais (ausência de antioxidantes e de carvão ativado; ausência de antioxidantes com 2 g L-1 de carvão ativado), com três repetições constituídas por quatro plantas. Após sete, 14 e 21 dias do cultivo in vitro foram avaliadas a porcentagem de contaminação bacteriana, fúngica e de explantes oxidados. Conclui-se que o cultivo in vitro de E. pyriformis, em relação as contaminações bacterianas e fúngicas, pode ser efetuado sem a utilização de agentes antioxidantes. Entretanto, para reduzir a oxidação fenólica deve ser utilizado o PVP ou ácido ascórbico, ambos na concentração de 300 mg L-1, associados a 2 g L-1 de carvão ativado.

Hypoglycemic Effect of Acupoint Injection of Sustained-release Insulin at Different Times in SD Rats / 上海针灸杂志

Objective To observe blood glucose values and serum insulin levels at different times after acupoint injection of insulin with PVP as a sustained release agent and analyze the correlation between them in SD Rats.Methods One hundred and forty-four male SD rats were randomized into groups A (acupoint injection of insulin alone), B (acupoint injection of sustained-release insulin) and C (control). At one hour after every group received an oral gavage of 40% glucose solution (2.2 g/kg), groups A and B were given point Zusanli injection and group C was not treated. In the three groups of rats, blood glucose values and serum insulin levels were measured at six time points: 0.5, 3, 6, 8, 10 and 24 hours after acupoint injection (in group C at the corresponding time points). In every group, the reaction of Point Zusanli region to the stimulation was observed by optical microscopy in at three time points: 3, 10 and 24 hours after acupoint injection.Results The glucose-lowering rate reached its peak at 3 hours after acupoint injection and then declined in groups A and B. The hypoglycemic effect tended to be stable at 6 hours after acupoint injection in group A and at 10 hours after acupoint injection in group B. The hypoglycemic effect was better in group B than in group A at 6 and 8 hours after acupoint injection (P<0.01). In group A, serum insulin reached its peak at 3 hours and tended to be stable at 6 hours after acupoint injection (P<0.05). Serum insulin levels were significantly lower in group B than in group A at four time pints: 0.5, 3, 6 and 8 hours after acupoint injection (P<0.05). An analysis of the correlation between rat serum insulin levels and the glucose-lowering rate showed a significant positive correlation in group A (P<0.01) and a low positive correlation in group B (P<0.05). In groups A and B of rats, clear stripes and complete structure of muscle fibers were seen with no obvious degeneration, necrosis and inflammatory reaction around point Zusanli at three time points: 3, 8 and 24 hours after acupoint injection; there were no obvious pathological changes compared with group C.Conclusions PVP as a sustained release agent can slow down the absorption rate of insulin in rat point Zusanli region. Meanwhile, it prolongs the continuous time of the hypoglycemic effect of insulin. There is a low correlation between serum insulin levels and the hypoglycemic effect, suggesting that acupoint injection with a sustained release agent can prolong the effect of acupoint injection of medicine.

Formulation and evaluation of simvastatin buccal film.

The aim of this work was to develop and evaluate a buccal film for delivery of simvastatin. Buccal films containing carboxymethyl cellulose (CMC) with and without Polyvinylpyrrolidone (PVP) as polymers were prepared. Tween 80 was included with and without propylene glycol (PG) to modulate the characteristics of the films. The films were prepared by solvent casting with drug concentration being maintained at 2.5 mg/cm2. In absence of Tween and PG, the films were opaque due to precipitation of drug. PG reduced the swelling index and increased the thickness of the film due to shrinkage. Incorporation of PVP into the films increased the bioadhesion force and time. The rate of drug release depended on the composition of the film with the presence of PVP increasing the release efficiency compared to the corresponding PVP free films. Similarly, incorporation of PG increased the drug release efficiency. Thermal analysis indicated the presence of the drug in amorphous form or as a solid solution in the film components. The developed films are promising for buccal administration of simvastatin.

Size Control of 99mTc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection

Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a 99mTc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with 99mTc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid (99mTc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid (99mTc-BPTC-50) were chosen for in vitro and in vivo studies. 99mTc-BPTC-50 (100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of 99mTc-PPTC-30 decreased over time, while 99mTc-BPTC-50 increased. Therefore, 99mTc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.

Effect of metal primers and tarnish treatment on bonding between dental alloys and veneer resin

PURPOSE: The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution's tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS: Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each alloy. Half specimens (n=12 per group) in tarnished group were immersed into polyvinylpyrrolidone solution for 24 hours. In Co-Cr and Ti-alloy, Alloy Primer (MDP + VBATDT) and MAC-Bond II (MAC-10) were applied, while Alloy Primer and V-Primer (VBATDT) were applied to Au-Ag-Pd alloys. After surface treatment, veneering composite resin were applied and shear bond strength test were conducted. RESULTS: Alloy Primer showed higher shear bond strength than MAC-Bond II in Co-Cr alloys and Au-Ag-Pd alloy (P<.05). However, in Ti alloy, there was no significant difference between Alloy Primer and MAC-Bond II. Tarnished Co-Cr and Au-Ag-Pd alloy surfaces presented significantly decreased shear bond strength. CONCLUSION: Combined use of MDP and VBATDT were effective in bonding of the resin to Co-Cr and Au-Ag-Pd alloy. Tarnish using polyvinylpyrrolidone solution negatively affected on the bonding of veneer resin to Co-Cr and Au-Ag-Pd alloys.

pH-sensitive polyvinylpyrrolidone-acrylic acid hydrogels: Impact of material parameters on swelling and drug release

In this study, we fabricated pH-sensitive polyvinylpyrrolidone/acrylic acid (PVP/AA) hydrogels by a free-radical polymerisation method with variation in the content of monomer, polymer and cross-linking agent. Swelling was performed in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strength. Network structure was evaluated by different parameters and FTIR confirmed the formation of cross-linked hydrogels. X-ray crystallography showed molecular dispersion of tramadol HCl. A drug release study was carried out in phosphate buffer solutions of pH 1.2, 5.5 and 7.5 for selected samples. It was observed that swelling and drug release from hydrogels can be modified by changing composition and degree of cross-linking of the hydrogels under investigation. Swelling coefficient was high at higher pH values except for the one containing high PVP content. Drug release increased by increasing the pH of the medium and AA contents in hydrogels while increasing the concentration of cross-linking agent had the opposite effect. Analysis of the drug release mechanism revealed non-Fickian transport of tramadol from the hydrogels.

Nesse estudo, preparamos hidrogéis de polivinilpirrolidona/ácido acrílico(PVP/AA), sensíveis ao pH, por meio de método de polimerização de radical livre, com variações no conteúdo de monômero, de polímero e de agente de ligação cruzada. O inchamento foi realizado em soluções tampão fosfato USP pH 1,2, 5,5, 6,5 e 7,5, com força iônica constante. A estrutura reticular foi avaliada por diferentes parâmetros e o FTIR confirmou a formação de hidrogéis de ligação cruzada. A cristalografia de raios X mostrou dispersão molecular do cloridrato de tramadol. Realizou-se estudo de liberação do fármaco em soluções tampão fosfato pH 1,2, 5,5 e 7,5 para amostras selecionadas. Observou-se que o inchamento e a liberação do fármaco dos hidrogéis podem ser modificados mudando-se a composição e o grau de ligação cruzada dos hidrogéis em estudo. O coeficiente de inchamento foi alto em pH mais altos, exceto para um deles com alto conteúdo de PVP. A liberação do fármaco aumentou com o aumento do pH do meio e do conteúdo em AA nos hidrogéis, enquanto que o aumento na concentração do agente de ligação cruzada apresentou efeito oposto. A análise do mecanismo de liberação do fármaco revelou transporte não Fickiano do tramadol dos hidrogéis.

Comparison of different methods for total RNA extraction from sclerotia of Rhizoctonia solani

Background Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is one of the most important pathogens of rice (Oryza sativa L.) that causes severe yield losses in all rice-growing regions. Sclerotia, formed from the aggregation of hyphae, are important structures in the life cycles of R. solani and contain a large quantity of polysaccharides, lipids, proteins and pigments. In order to extract high-quality total RNA from the sclerotia of R. solani, five methods, including E.Z.N.A.™ Fungal RNA Kit, sodium dodecyl sulfate (SDS)-sodium borate, SDS-polyvinylpyrrolidone (PVP), guanidinium thiocyanate (GTC) and modified Trizol, were compared in this study. Results The electrophoresis results showed that it failed to extract total RNA from the sclerotia using modified Trizol method, whereas it could extract total RNA from the sclerotia using other four methods. Further experiments confirmed that the total RNA extracted using SDS-sodium borate, SDS-PVP and E.Z.N.A.™ Fungal RNA Kit methods could be used for RT-PCR of the specific amplification of GAPDH gene fragments, and that extracted using GTC method did not fulfill the requirement for above-mentioned RT-PCR experiment. Conclusion It is concluded that SDS-sodium borate and SDS-PVP methods were the better ones for the extraction of high-quality total RNA that could be used for future gene cloning and expression studies, whereas E.Z.N.A.™ Fungal RNA Kit was not taken into consideration when deal with a large quantity of samples because it is expensive and relatively low yield.

Molecular dynamics simulation on mechanical properties of PVP/PVA / 医用生物力学

Objective To study the mechanical properties of PVP/PVA composite hydrogel and its interaction principle based on the molecular dynamics (MD) theory. Methods MD simulation was applied to investigate mechanical properties and radial distribution functions of PVP, PVA and their mixed system PVP/PVA. Results Compared with the pure PVP, mechanical properties of PVP/PVA were significantly improved, and not affected by temperature. The interaction between PVA and PVP was expected to occur through the interchain hydrogen bonding between the oxygen atom of PVP and the hydroxyl group of PVA. Conclusions MD method revealed the interaction mechanism of PVP/PVA hydrogel at molecular microscopic level and proved it better than pure PVP. Meanwhile, its mechanical properties were stable at different environment temperatures. These results provide a reliable theoretical research method for studying the fabrication process of hydrogel prosthesis in clinic and its mechanical properties.

Formulation and evaluation of transdermal patches and to study permeation enhancement effect of eugenol.

Since oral bioavailability of Propranolol Hydrochloride is poor due to high first pass metabolism different matrix- type transdermal patches incorporating Propranolol Hydrochloride were formulated with an objective to study the effect of polymers on transdermal release of the drugs. The polymers selected for sustaining the release of drug were polyvinylpyrrolidone, Hydroxypropylmethycellulose (HPMC) and Ethyl cellulose (EC). The patches were formulated using combination of polymers and propylene glycol as plasticizer. The physicochemical evaluation of the polymer matrices was performed for suitability. In vitro permeation studies were performed using rat abdominal skin as the permeating membrane in Franz diffusion cell. The result indicated that maximum release was obtained at 2% solution of EC. Optimized batch was evaluated for permeation enhancement through rat skin using natural permeation enhancer Eugenol and it was concluded that permeation enhancement through Eugenol was comparable to the commercially available permeation enhancer Dimethyl sulfoxide 1% (DMSO). All the films were found to be stable at 37ºC and 45ºC with respect to their physical parameters and drug content.

Formulation and characterization of gastroretentive discs containing famotidine

In this work a different type of formulation, as disc, containing a selected mucoadhesive polymer, fillers, and binders were investigated for their potential as a mucoadhesive gastroretentive delivery system to deliver famotidine in the stomach. Various types of hydrophilic diluents were evaluated for their swelling and mucoadhesive property and one (polyvinylpyrrolidone, PVP) was selected to combine with the selected mucoadhesive polymer (polyethylene oxide, PEO). Discs with different ratios of PEO and PVP were prepared and evaluated for swelling, dissolution, and mucoadhesion. The swelling property of the discs increased as the concentration of PEO was increased and also did the mucoadhesion. These discs retained their integrity and adherence onto gastric mucosa for more than 10 h under in-vitro conditions. The PEO, in combination with PVP, yielded a non-disintegrating type mucoadhesive dosage form which was suitable for gastroretentive applications to achieve the desired release profile of the drug.

Hydroxypropylcellulose controlled release tablet matrix prepared by wet granulation: effect of powder properties and polymer composition

The aim of this study was to attain 100 percent drug release of caffeine after 24 h from hydroxypropylcellulose (HPC) tablet matrices and to investigate the effect of co-excipient. Physical properties of the powders were evaluated and suggested for a wet granulation process. The tablet containing caffeine was formulated by different weight ratios of hydrophilic polymers. The results of polymer evaluation confirmed that the increase of HPC level with the same drug content significantly decreased the rate of drug release. The presence of co-polymer excipients carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) in the tablet matrix was also investigated. The release rate was also controlled by low levels of CMC (<10 percent) while PVP did not show any considerably effect. The best fit release rate 100 percent at 24 h was obtained when 10 percent of α-lactose monohydrate was added to the formulation.

O objetivo deste estudo é desenvolver a liberação 100 por cento da droga cafeína em 24 horas em comprimidos matrizes e investigar o uso de hidroxipropilcelulose (HPC) mais os efeitos de co-excipiente. As propriedades físicas dos pós foram avaliadas assim como seu uso no processo de granulação úmida. O comprimido contendo a cafeína foi formulado por diferentes relações de peso dos polímeros hidrofílicos. Os resultados da avaliação do polímero confirmaram que o aumento do nível de HPC com o mesmo índice da droga diminuiu significativamente a taxa de liberação da droga. A presença do co-polímero excipiente carboximetilcelulose (CMC) e do polivinilpirrolidona (PVP) na matriz do comprimido foi também investigado. A taxa de liberação foi controlada principalmente por baixos níveis de CMC (< 10 por cento) enquanto PVP não mostrou efeito diferente considerável. A melhor taxa de liberação de cafeína 100 por cento em 24 horas foi obtida quando 10 por cento da lactose monoidrato foi adicionado na formulação.

The curative effect of the pressure sore treated by iodophors associating with oxygen and peptide / 中国基层医药

Objective To explore the curative effect of the pressure sore treated by iodophors associating with oxygen and peptide. Method 36 cases with pressure sore in stage Ⅲ and stage Ⅵ were randomly divided into the observation group and the control group. After ebriding was carried out in both groups, the control group was trea-ted with the rout change dressing and the other group was treated by iodophors associating with oxygen and peptide es-pecially. Result The cicatrization time of the observation group was remarkablely shorter than the control group. Conclusion Treating the pressure sore by iodopbors associating with oxygen and peptide has the advantage of less passion, shorter course of treatment, better curative effect, economy and mote convenience which is worth for the pro-moting of clinical usage.

Optimization of the Formulation and Technology of Lovastatin Capsule by Orthogonal Test / 中国药房

OBJECTIVE: To optimize the preparation technology for the lovastatin capsules.METHODS: Orthogonal test was used to optimize the conditions for the technology of preparation meanwhile a dissolution test was conducted.RESULTS: According to the results of the single factor analysis and orthogonal test,the optimal condition for the lovastatin capsules were as follows: agglomerant: 10%PVP;disintegrator: CMS-Na was used by combining exterior and interior addition(2∶1);stuffing capsule by granules;wetting agent of twice granulating: 75% alcohol.The 30 min dissolution rate of the capsules prepared in the optimized technology reached above 92%.CONCLUSION: This preparation is stable in technology,reproducible and with high dissolution rate.

Influence of polyvinylpyrrolidone and hydroxypropyl - beta - cyclodextrine on solubility of dehydro epiandrosterone

PVP only does not enhance the solubility of DHEA but a combination effect will manifeste once the substance is used concurrently with HPCD. In 5,59% HPCD solution, this solubility was enhanced by 115 times and in 5,59% HPCD solution adding 0,1% PVP it was enhanced by 139 times. There is a strict interaction between its components, different evidently from the physical mixed graphic

Preparation and dissolution of solid dispersion of Fructus Schisandrae Chinensis extracts / 中草药

Objective To prepare Wurenchun solid dispersion of alcohol extracts of Fructus Schisandrae Chinensis so as to improve the dissolution of its active compound in vitro.Methods The Wurenchun solid dispersions were prepared with various carriers and drug/carrier ratios by mixing the carrier in alcohol extractive solution of FSC directly,and the apparent solubility and dissolution of deoxyschisandrin in them were tested and compared.Results The apparent solubility and dissolution of deoxyschisandrin of Wurenchun solid dispersion(extracts: polyvinylpyrrolidone(PVP) K30=1∶3) were increased remarkably to 5.06 ?g/mL and 43.2% in water individually,including dispersed and dissolved drug whose particle size is below 0.22 ?m,compared with that of the self-prepared Wurenchun capsules.Conclusion Wurenchun solid dispersion made of PVP K30 can remarkably enhance apparent solubility and dissolution of the active compound in vitro.

Study on Optimization of Nano-silver Prepared by Method of Liquid Reduction / 环境与健康杂志

Objective The various influencing factors in the process of nano-silver preparation were studied in order to prepare nano-silver that has uniformity particle size distribution and good crystallinity. Methods Through the method of liquid reduction at room temperature,the nano-silver powders were prepared directly using silver nitrate as raw material,water as the reactive medium,polyvinylpyrrolidone(PVP) as protecting agent and ammonium formate as reducing agent. By means of EDS and TEM(transmission electron microscopy),the prepared silver particles were characterized. The various influencing factors in the process of preparation were also discussed. Results With the increasing concentration of AgNO3,the particle diameter of nano-silver changed obviously. When the concentration of silver nitrate was 0.25-0.30 mol/L,the size of product is the smallest. With the increasing concentration of reductant,the diameter of nano-silver decreased gradually. While at the concentration of 0.70 mol/L HCOOH,the average diameter of nano-silver is not more than 10 nm. Smaller and more well-distributed silver powder could be prepared at ratio of concentration of PVP to AgNO3 with the value of 1.5-1.0,at which PVP presented effective protection. Conclusions This method can prepare particle of nano-silver which revealed well dispersed and uniform size. The process is stable and reliable,easy to operate,high yields and suitable for industrial production.

Osteonecrosis of the Femoral Head Associated with Polyvinylpyrrolidone Storage / 대한정형외과학회잡지

Eighteen cases of osteonecrosis of the femoral head associated with macromolecular polyvinylpyrrolidone (PVP) deposition were analysed on the basis of clinical, radiologic and pathologic features. The cases were observed during 8 years period from January, 1974 to December, 1981. The pathogenesis of the osteonecrosis of the femoral head due to PVP storage in reticuloendothelial system were discussed in detail. Parenteral administration of high-molecular PVP in repeated, long duration led to osteonecrosis of the femoral head. Storage of PVP in the histiocytes of the bone marrow resulted in osteonecrosis of the femoral head followed by microciculation disturbance. PVP-induced osteonecrosis were manifested as multiple foci of necrosis involving not only the femoral head, other long bones around joints, but also the visceral reticuloendo-thelial system characterized by infiltrates of histiocytes laden with PVP. The patients with PVP induced osteonecrosis complianed multiple joint pain in their early course of the disease. On roentgenogram, osteonecrosis were often noted in the hip, shoulder, knee, and ankle in order or frequency. Foamy histiocytes laden with PVP were characteristic on hematoxylin-eosin stain diagnostic on Weigert's elastica, phosphotungstic acid hematoxylin, and Congo red stains. As far as rationale of the treatment concerning a number of staging systems for Osteonecrosis, the choice of surgical procedures were similar to those given by W.F. Enneking et al. In the series, we have performed two hips in total surface replacement, 26 hips in total hip replacement mostly for 3rd generation-configuration of Charnley prosthesis. In addition, one case for free vascularized fibula graft and trans-trochanteric rotational osteotomy after Sugioka were also included for this study. The result of treatment was rather optimistic. However, complications have occured in 4 hips of 3 patients which required removal of whole prosthetic components. Therefore, we underwent revisional surgery in three out of four hips subsequently during the short post-poerative follow-up. These will be published in the future.