Three-dimensional printed poly (L-lactide) and hydroxyapatite composite for reconstruction of critical bone defect in rabbits

ABSTRACT Purpose To use a 3D printed poly (L-lactide) acid (PLLA) and hydroxyapatite (HA) composite as a bone substitute for reconstruction of a critical bone defect in the radius of rabbits. Methods A 1.5 cm ostectomy was performed in the radial diaphysis of 60 New Zealand white rabbits. The rabbits were divided into three groups according to surgical treatment of the bone defect (group I - control, group II - bone graft, group III - 3D PLLA). Each group was divided into four subgroups with different radiographic and histopathologic evaluation times (T1 - 15 days, T2 - 30 days, T3 - 60 days, T4 - 90 days). Results The implant group had greater clinically lameness (p = 0.02), edema (p = 0.007), pain (p = 0.04) and more complications at the surgical site (p = 0.03). Histologically, this group showed greater congestion (p = 0.04), hemorrhage (p = 0.04) and inflammation. Osteogenesis was microscopically similar between days (p = 0.54) and treatments (p = 0.17), even though radiographically, more effective bone healing occurred in the graft group (II), with more callus and bone bridge formation. Conclusions The customization of a 3D PLLA/HA scaffold was successful. However, in animals receiving the polymer-ceramic composite less bone callus and bone bridge was formed compared to the graft group.

Poly(trimethylene carbonate-co-L-lactide) electrospun scaffolds for use as vascular grafts

Currently, there is great clinical need for suitable synthetic grafts that can be used in vascular diseases. Synthetic grafts have been successfully used in medium and large arteries, however, their use in small diameter vessels is limited and presents a high failure rate. In this context, the aim of this study was to develop tissue engineering scaffolds, using poly(trimethylene carbonate-co-L-lactide) (PTMCLLA), for application as small diameter vascular grafts. For this, copolymers with varying trimethylene carbonate/lactide ratios - 20/80, 30/70, and 40/60 - were submitted to electrospinning and the resulting scaffolds were evaluated in terms of their physicochemical and biological properties. The scaffolds produced with PTMCLLA 20/80, 30/70, and 40/60 showed smooth fibers with an average diameter of 771±273, 606±242, and 697±232 nm, respectively. When the degradation ratio was evaluated, the three scaffold groups had a similar molecular weight (Mw) on the final day of analysis. PTMCLLA 30/70 and 40/60 scaffolds exhibited greater flexibility than the PTMCLLA 20/80. However, the PTMCLLA 40/60 scaffolds showed a large wrinkling and their biological properties were not evaluated. The PTMCLLA 30/70 scaffolds supported the adhesion and growth of mesenchymal stem cells (MSCs), endothelial progenitor cells, and smooth muscle cells (SMCs). In addition, they provided a spreading of MSCs and SMCs. Given the results, the electrospun scaffolds produced with PTMCLLA 30/70 copolymer can be considered promising candidates for future applications in vascular tissue engineering.

Comparative study of peritoneal adhesions after intraperitoneal implantation in rats of meshes of polypropylene versus polypropylene/polyglecaprone versus polyester/porcine collagen

Abstract Purpose To Compare the extent and intensity of adhesions formed between the intra-abdominal organs and the intraperitoneal implants of polypropylene mesh versus polypropylene/polyglecaprone versus polyester/porcine collagen used for correction of abdominal wall defect in rats. Methods After the defect in the abdominal wall, thirty Wistar rats were placed in three groups (ten animals each) for intraperitoneal mesh implant: polypropylene group, polypropylene/polyglecaprone group, and polyester/porcine collagen group. The macroscopic evaluation of the extent and intensity of adhesions was performed 21 days after the implant. Results The polypropylene group had a higher statistically significant impairment due to visceral adhesions (p value = 0.002) and a higher degree of intense adherence in relation to polypropylene/polyglecaprone and polyester/porcine collagen groups (p value<0.001). The polyester/porcine collagen group showed more intense adhesions than the polypropylene/polyglecaprone group (p value=0.035). Conclusions The intraperitoneal implantation of polypropylene meshes to correct defects of the abdominal wall caused the appearance of extensive and firm adhesions to intra-abdominal structures. The use of polypropylene/polyglecaprone or polyester/porcine collagen tissue-separating meshes reduces the number and degree of adhesions formed.

Absorbable suture. Best aesthetic outcome in cesarian scar

Abstract Purpose: To compare two suture threads, poliglecaprone 25 and nylon, used as intradermal suture for skin closure in women undergoing their first cesarean section. Methods: This is a randomized clinical trial. A total of 60 women undergoing their first cesarean section were enrolled and prospectively assessed. They were randomly allocated to group I (n=30), which received an intradermal suture with nylon 4.0 or to group II (n=30), which had an intradermal suture with poliglecaprone 25, 4.0. The main author took standardized photographs of the scar 6 months after the operation. Four independent raters, two senior obstetricians and two senior plastic surgeons (a male and a female physician from each specialty) assessed the photographs.The panelists rated the scar according to Trimbos scale, composed by the subscales hypertrophy, color and width of the scar. Results: At baseline, patients in both groups were similar regarding age and body mass index. Five patients withdraw the study, four from group and one from group II. Scars of patients from group II were significantly less hypertrophic (p=0.001), thinner (p=0.019) and had more acceptable color (p=0.019). Conclusion: The intradermal suture with poliglecaprone 25 for skin closure after cesarean incision provides better aesthetic result.

Comparison of two different suture techniques in laparoscopic partial nephrectomy

ABSTRACT Objective: To comparatively evaluate the traditional interrupted knot-tying and running suture renorrhaphy with Monocryl® in laparoscopic partial nephrectomy (LPN). Materials and Methods: A retrospective analysis of 62 consecutive patients undergoing LPN using traditional interrupted knot-tying suture renorrhaphy (Group 1; n=31) or running suture technique renorrhaphy with 2-0 monofilament polyglecaprone (Monocryl®, Ethicon) (Group 2; n=31) from December 2011 to October 2015 at the University. All patients underwent LPN performed by an experienced laparoscopic surgeon. The demographic, perioperative and postoperative parameters were compared between the groups, and the effect of both suture techniques on the warm ischemic time (WIT) and trifecta were evaluated. Results: The running suture renorrhaphy with Monocryl® reduced WIT, estimated blood lost and length of hospitalization stay significantly without increasing postoperative complication rate during LPN in comparison with interrupted knot-tying suture. Conclusion: The renorrhaphy using the running suture with Monocryl® is an effective and safe technique with the advantage of shortening WIT even in more challenging and larger tumors during LPN.

Tensiometric analysis of meshes used in abdominal ventral wall defects in rats / Estudo tensiométrico de telas utilizadas na correção de defeito na parede abdominal ventral de ratos

ABSTRACT Background: Among the various strategies to avoid exaggerated foreign body reaction in the treatment of hernias is the limitation of the amount of polypropylene or the use of absorbable material. Aim: To evaluate the healing of defects in the abdominal wall of rats, comparing microporous polypropylene, macroporous polypropylene and polypropylene/polyglecaprone at the 30º, 60º and 120º postoperative day. Methods: Wistar rats were submitted to defect production in the ventral abdominal wall, with integrity of the parietal peritoneum. Prolene®, Ultrapro® and Bard Soft® meshes were used in the correction of the defect. Nine subgroups of 10 animals were submitted to euthanasia at 30th, 60th and 120th postoperative day. Fragments of the abdominal wall of the animals were submitted to tensiometric analysis. Results: The tensiometry at the 30th postoperative day showed greater resistance of the tissues with Bard Soft® (macroporous mesh) in relation to the tissues with Prolene® (microporous mesh). On the 60th postoperative day Bard Soft® maintained the superior resistance to the tissues comparing to Prolene Mesh®. On the 120th postoperative day the tissues repaired with Ultrapro® (macroporous mesh) proved to be more resistant than the ones by Prolene® (microporous mesh) and Bard Soft® (macroporous mesh). Conclusion: The tissues repaired with macroporous meshes showed greater resistance than with microporous meshes at all stages, and at 120 days postoperative Ultrapro® performed better than the others.

RESUMO Racional: Dentre as várias estratégias para evitar exagerada reação de corpo estranho no tratamento das hérnias está a limitação da quantidade de polipropileno na tela ou utilização de material absorvível. Objetivo: Avaliar a cicatrização de defeito em parede abdominal de ratos, comparando-se as telas de polipropileno microporosa, polipropileno macroporosa e polipropileno/poliglecaprone. Métodos: Em 90 ratos Wistar foi produzido defeito na parede abdominal ventral, com integridade do peritônio parietal. Na correção foram utilizadas as telas Prolene®, Ultrapro® e Bard Soft®. Nove subgrupos de 10 animais foram submetidos à eutanásia no 30º, 60º e 120º dia do pós-operatório. Fragmentos da parede abdominal dos animais foram submetidos à análise tensiométrica. Resultados: A tensiometria aos 30dias mostrou maior resistência do tecido com tela Bard Soft® em relação à de Prolene®; no 60º dia a Bard Soft® manteve a resistência superior ao Prolene®; no 120º dia a reparação com tela macroporosa Ultrapro® mostrou-se mais resistentes que a de Prolene® e Bard Soft®. Conclusão: Os tecidos reparados com telas macroporosas demonstraram maior resistência do que as microporosas em todas as fases, sendo que aos 120 dias de pós-operatório a Ultrapro® teve melhor desempenho que as demais.

Characteristics of the fibroplasia and collagen expression in the abdominal wall after implant of the polypropylene mesh and polypropylene/polyglecaprone mesh in rats

ABSTRACT PURPOSE: To compare fibroplasia and the resistance of the abdominal wall when polypropylene meshes and polypropylene/poliglecaprone are used. METHODS: Seventy-seven male Wistar rats were divided into three groups: Control Group (for resistance); Group E (polypropylene mesh); and Group U (polypropylene/poliglecaprone mesh). The animals in Groups E and U had a standard muscular and aponeurotic defect, with integral peritoneum, and correction with the mesh. Measurements were taken 4, 7, 14, 28 and 56 days after surgery. The resistance, and collagen density were studied. RESULTS: Resistance on the 56th day was similar in both meshes. The gain in resistance described an ascending curve for the polypropylene mesh and was irregular in the case of the polypropylene/poliglecaprone. Fibroplasia showed a gain in type I and type III collagen in both groups (p<0.001). Collagen III stabilized in the 14th day and collagen I continued to ascend. CONCLUSIONS: The gain in resistance of the polypropylene mesh is regular and ascending, whereas the polypropylene/poliglecaprone is not regular. The final resistance of both meshes is similar; the collagen density increases over time, and show the same inflammatory potential.

In vivo performance of different scaffolds for dental pulp stem cells induced for odontogenic differentiation

Abstract This study was designed to determine the in vivo performance of three different materials as scaffolds for dental pulp stem cells (DPSC) undergoing induced odontogenic differentiation. An odontogenic medium modified by the addition of recombinant human bone morphogenetic protein 2 was used in the experimental groups to induce differentiation. Mesenchymal stem cell medium was used in the control groups. DPSC were transplanted onto the backs of mice via three scaffolds: copolymer of L-lactide and DL-lactide (PLDL), copolymer of DL-lactide (PDL) and hydroxyapatite tricalcium phosphate (HA/TCP). The expression levels of dentin sialo-phosphoprotein (DSPP), dentin matrix protein-1 (DMP1), enamelysin/matrix metalloproteinase 20 (MMP20) and phosphate-regulating gene with homologies to endopeptidases on X chromosome (PHEX) were analysed using RT-PCR. The expressions in the experimental groups were compared to those in the control groups. The transcript expressions at 6 and 12 weeks were significantly different for all scaffolds (p < 0.05), except for the expression of DSPP in the PLDL group with regard to the time variable. Although there was a decrease in the expression of enamelysin/MMP20 in PLDL and HA/TCP at 12 weeks, all other expressions increased and reached their highest level at 12 weeks. The highest DSPP expression was in the PDL group (p < 0.05). The highest expression of DMP1 was detected in the HA/TCP group (p < 0.05). The highest expression of PHEX was in the PLDL group (p < 0.05). Consequently, PLDL and PDL seemed to be promising scaffold candidates for odontogenic regeneration at least as HA-TCP, when they were applied with the DPSC induced for odontogenic differentiation.

Polypropylene and polypropylene/polyglecaprone (Ultrapro(r)) meshes in the repair of incisional hernia in rats

PURPOSE: To compare the inflammatory response of three different meshes on abdominal hernia repair in an experimental model of incisional hernia. METHODS: Median fascial incision and skin synthesis was performed on 30 Wistar rats. After 21 days, abdominal hernia developed was corrected as follows: 1) No mesh; 2) Polypropylene mesh; and, 3) Ultrapro(r) mesh. After 21 days, the mesh and surrounding tissue were submitted to macroscopic (presence of adhesions, mesh retraction), microscopic analysis to identify and quantify the inflammatory and fibrotic response using a score based on a predefined scale of 0-3 degrees, evaluating infiltration of macrophages, giant cells, neutrophils and lymphocytes. RESULTS: No significant difference was seen among groups in adherences, fibrosis, giant cells, macrophages, neutrophils or lymphocytes (p>0.05). Mesh shrinkage was observed in all groups, but also no difference was observed between polypropylene and Ultrapro mesh (7.0±9.9 vs. 7.4±10.1, respectively, p=0.967). Post-operatory complications included fistula, abscess, dehiscence, serohematic collection and reherniation, but with no difference among groups (p=0.363). CONCLUSION: There is no difference between polypropylene (high-density) and Ultrapro(r) (low-density) meshes at 21 days after surgery in extraperitoneal use in rats, comparing inflammatory response, mesh shortening, adhesions or complications. .

Inflammatory reaction and tensile strength of the abdominal wall after an implant of polypropylene mesh and polypropylene/poliglecaprone mesh for abdominal wall defect treatment in rats

PURPOSE: To compare the inflammatory reaction and the growing resistance of the abdominal wall with the use of poliglecaprone meshes and polypropylene meshes associated with poliglecaprone in the correction of abdominal defects. METHODS: Seventy-seven Wistar rats were divided into three groups: CG (non-operated animals: EG (polypropylene mesh) and UG (polypropylene and poliglecaprone mesh). A muscular and aponeurotic defect was formed and treated according to the group. Evaluations were made after 4, 7, 14, 28 and 56 days. The resistance and inflammatory pattern were studied. RESULTS: There was a gradual and significant gain in resistance, regularly in the EG and irregularly in the UG, which was lower on the 14th day (p=0.008). The inflammatory reaction was acute and more intense in the UG on the fourth day. At all other times, the inflammatory pattern was acute to chronic, similar in both groups, with minimum intensity on the 56th day. CONCLUSION: The greater resistance offered by the polypropylene mesh was regular and ascending, stabilizing on the 28th day, while that of the polypropylene/poliglecaprone was not even. In the end, the resistances were similar. The inflammatory response was greater in the UG on the fourth day and similar at all other times. .

Estudo comparativo entre os fios de algodão, poliglactina e poliglecaprone nas anastomoses intestinais de cães / Comparative study of cotton, polyglactin and polyglecaprone sutures in intestinal anastomoses in dogs

RACIONAL: Nos últimos anos muitos fios de sutura foram desenvolvidos e depois abandonados. Até hoje não foi encontrado um fio cirúrgico ideal aos intestinos ou a outros tecidos de um modo geral, tornando sua escolha tarefa difícil. OBJETIVO: Avaliar macro e microscopicamente a cicatrização de anastomoses do intestino delgado de cães, utilizando suturas com fios de poliglecaprone 25; poliglactina 910 e algodão. MÉTODOS: Vinte cães machos adultos foram operados e submetidos a três anastomoses no intestino delgado empregando a técnica extramucosa com pontos separados. Foram utilizados os três tipos fios e as anastomoses foram analisadas em diferentes períodos no pós-operatório: grupo I -três dias; grupo II - sete dias; grupo III - 14 dias; grupo IV - 21dias. A análise macroscópica consistiu em avaliar a presença ou não de peritonite, aspecto das anastomoses e aderências. Os estudos histológicos das anastomoses, empregando a hematoxilina e eosina e o tricrômico de Masson analisaram a inflamação exsudativa, inflamação granulomatosa, o revestimento epitelial da mucosa e as fibras colágenas. RESULTADOS: Na avaliação macroscópica os fios apresentaram boa coaptação das bordas com moderado grau de aderência entre alças e omento do 3º ao 21º dia do pós-operatório. A avaliação microscópica mostrou inflamação exsudativa com neutrófilos e fibrina que variou de discreta a moderada até o 14º dia; inflamação granulomatosa com presença de macrófagos, células gigantes multinucleadas e células epitelioides mais evidentes ao 14º dia para o fio algodão; presença de tecido de granulação (fibroblastos) e fibras colágenas, de forma moderada, a partir do 7º dia para os três fios. CONCLUSÃO: Os três tipos de fios de sutura apresentaram comportamento semelhante, com boa cicatrização e podem ser recomendados em anastomoses do intestino delgado.

BACKGROUND: Over the years, many sutures were developed and then abandoned. Until now was not found an ideal suture to the intestinal tract or other tissues in general, making the choice a difficult task. AIM: To evaluate, macroscopically and microscopically, the healing process of intestinal anastomoses in dogs using polyglecaprone 25, polyglactin 910 and cotton sutures. METHODS: Twenty adult male dogs were operated on and underwent to three small bowel anastomosis using the technique with submucosal sutures. Were used three threads and the anastomoses were evaluated at different postoperative periods - group I - three days; group II - seven days; group III - 14 days and group IV - 21days. Macroscopic analysis was to assess the presence or absence of peritonitis, aspect of the anastomosis and adhesions. Histological studies of the anastomoses, using hematoxylin and eosin and Masson's trichrome analyzed the exudative inflammation, granulomatous inflammation, the mucosal epithelial coating and collagen fibers. RESULTS: The macroscopic analysis showed good coaptation of the edges with a moderate degree of adhesion between the intestines and omentum three to 21 days after surgery. The microscopic evaluation revealed exudative inflammation with neutrophils and fibrin, which ranged from mild to moderate until the 14th day; granulomatous inflammation with macrophages, multinucleated giant cells and epithelioid cells were more evident at 14th day for the cotton, presence of granulation tissue (fibroblasts) and collagen fibers, a moderate way, from the 7th for the three threads. CONCLUSION: All three threads showed similar behavior and thus they can be indicated for anastomoses of the small intestine.

Effect of copaiba oil on correction of abdominal wall defect treated with the use of polypropylene/polyglecaprone mesh

PURPOSE: To evaluate the effects of copaiba oil on the correction of abdominal defect treated with the use of polypropylene/polyglecaprone mesh in rats. METHODS: A defect in the abdominal wall was created and corrected with polypropylene/polyglecaprone mesh in 36 rats. They were randomly distributed into three groups: control, copaiba by oral administration (gavage) and copaiba oil dip in the mesh. Euthanasia was performed after seven, 14 and 21 post-operative days. The healing process was analyzed regarding the meshes and macroscopic and microscopic aspects. RESULTS: All animals had abdominal adhesions, which were smaller in the copaiba (gavage) group (p<0.05). In microscopy, all animals had an acute inflammation stage and the inflammatory response was best characterized by foreign body-type granulomas around the mesh fragments, which was not found in the mesh fragments within the copaiba dip group. There was a greater area of necrosis and fibrosis in the copaiba dip group compared to the control group (p<0.05). The copaiba (gavage) group had a greater quantity of collagen fibers compared to the control group. CONCLUSION: Copaiba oil administered by gavage decreased the amount of abdominal adhesions, besides accelerating the process of collagen fibers formation, without damages within the early stages of healing. However, when used by dip directly on the mesh, it had corrosive effects compromising the healing process of the abdominal wall.

Comparative study between polypropylene and polypropylene/poliglecaprone meshes used in the correction of abdominal wall defect in rats / Estudo comparativo entre as telas de polipropileno e polipropileno/poliglecaprone utilizadas na correção de defeito na parede abdominal ventral de ratos

PURPOSE: To evaluate the healing process of a defect in the ventral abdominal wall of rats, comparing the polypropylene and polypropylene/poliglecaprone meshes on the 30th and 60th postoperative day. METHODS: Thirty two Wistar rats were submitted to a ventral abdominal wall defect, with integrity of the parietal peritoneum. In the repair, were used polypropylene (group A) and polypropylene/poliglecaprone (group B) meshes. The groups were subdivided into four subgroups of eight animals euthanized on the 30th (A30 and B30) and 60th postoperative day (A60 and B60). Fragments of the abdominal wall of the animals were submitted to macroscopic, tensiometric and histological evaluations. RESULTS: The tensiometry on subgroup A30 showed a mean average break point of 0.78 MPa and in A60, 0.66 Mpa. In subgroup B30 it was 0.84 MPa and in B60, 1.27 Mpa. The score of the inflammatory process showed subacute phase on A30 and B30 sub-groups and chronic inflammatory process in subgroups A30 and 60B. CONCLUSIONS: The tensile strength was higher on the wall repaired by polypropylene/poliglecaprone mesh in the 60th post-operative day. Histology showed higher concentration of fibrosis on the surface of the polypropylene mesh with a tendency to encapsulation. In polypropylene/poliglecaprone subgroups the histology showed higher concentration of fibrosis on the surface of mesh filaments.

OBJETIVO: Avaliar a cicatrização de um defeito, na parede abdominal ventral de ratos, comparando-se as telas de polipropileno e polipropileno/poliglecaprone no 30º e 60º dia do pós-operatório. MÉTODOS: Trinta e dois ratos Wistar foram submetidos à produção de defeito na parede abdominal ventral, com integridade do peritônio parietal. Na correção foram utilizadas as telas de polipropileno (grupo A) e polipropileno/poliglecaprone (grupo B). Houve subdivisão em quatro subgrupos (A30, A60, B30 e B60) de oito animais que foram submetidos à eutanásia no 30º e 60º dia do pós-operatório. Fragmentos da parede abdominal foram submetidos à análise macroscópica, tensiométrica e histológica. RESULTADOS: A tensiometria no subgrupo A30 mostrou tensão média de ruptura de 0,78 Mpa e no subgrupo A60 de 0,66 MPa. No subgrupo B30 foi de 0,84 MPa e no B60 de 1,27 MPa. O escore do processo inflamatório mostrou fase subaguda nos subgrupos A30 e B30 e processo inflamatório crônico no subgrupo A60 e B60. CONCLUSÕES: A resistência à tensão foi maior na parede reparada pela tela de polipropileno/poliglecaprone no 60º dia pós-operatório. Na análise histológica houve maior concentração da fibrose na superfície da tela de polipropileno com tendência ao encapsulamento. Nos subgrupos polipropileno/poliglecaprone a análise histológica mostrou maior fibrose entre os filamentos da tela.

Cecorraphy in single layer using polypropylene and poliglecaprone 25 threads: comparative study in rats / Cecorrafia em plano único com fios de polipropileno e poliglecaprone 25: estudo comparativo em ratos

PURPOSE: To compare sutures with polypropylene and poliglecaprone 25 after partial cecotomy in rats. METHODS: Thirty six rats divided into two groups, A and B, of 18 animals; each group was also divided into three subgroups of six animals sacrificed at 4th, 7th and 14th days after surgery. Were studied the mortality, morbidity, complications attributable to sutures, macroscopy, optical microscopy and measurement of hydroxyproline at the level of the suture. RESULTS: There were no deaths or wound complications such as hematoma, seroma, abscess, evisceration or eventration. On microscopic evaluation reepithelization, coaptation and inflammation in both groups did not differ significantly. The average rate of tissue hydroxyproline found in the samples on the 4th day after surgery, was 21.38 mg/g tissue for group A and 16.68 mg/g for group B; on day 7 after surgery, the average was 15.64 mg/g tissue for group A and 26.53 mg/g for group B; on day 14, the average was 8.09 mg/g tissue for group A and 25.07 mg/g for group B. CONCLUSION: There were no differences on clinical evolution, macroscopic aspect, microscopic data and hydroxyproline concentration on both sutures.

OBJETIVO: Comparar a sutura com fio de polipropileno e poliglecaprone 25 após cecotomia parcial em ratos. MÉTODOS: Trinta e seis ratos foram distribuídos em dois grupos A e B de 18 animais, e cada grupo foi dividido em três subgrupos de seis, sacrificados no 4º, 7º e 14º dias do pós-operatório. Estudou-se a mortalidade, morbidade, complicações atribuíveis às suturas, macroscopia, microscopia ótica e dosagem de hidroxiprolina no nível da sutura. RESULTADOS: Não houve mortalidade ou complicações da ferida operatória como hematoma, seroma, abscesso, evisceração ou eventração. Na avaliação microscópica os critérios de re-epitelização, coaptação e processo inflamatório ambos os grupos não apresentaram diferença significativa. A taxa tecidual média da hidroxiprolina encontrada nas amostras no 4º dia de pós-operatório foi de 21,38 mg/g de tecido para o grupo A e 16,68 mg/g para o grupo B; no 7º dia a média foi de 15,64 mg/g de tecido para o grupo A e 26,53 mg/g para o grupo B; no 14º dia ela foi de 8,09 mg/g de tecido para o grupo A e 25,07 mg/g para o grupo B. CONCLUSÃO: Não houve diferença estatística entre a evolução clínica, avaliação macroscópica, microscopia e dosagem de hidroxiprolina entre as suturas realizadas com os fios estudados.

Correlating the solubility of indomethacin in 1.4-dioxane + water mixtures by means of the Jouyban-Acree model / Correlación de la solubilidad de indometacina en mezclas 1.4-dioxano + agua mediante el modelo de Jouyban-Acree

In this work the validity of the Jouyban-Acree and Yalkowsky-Roseman models is evaluated to correlate the solubility of indomethacin in 1,4-dioxane + water cosolvent mixtures. The solubility correlation is studied as a function of temperature and cosolvent composition. Both models require only the experimental solubility values in the pure solvents at all the temperatures evaluated. The solubility calculated values by using both models deviate notoriously from experimental values in several cases.

En este trabajo se evaluó la utilidad de los modelos Jouyban-Acree y Yalkowsky-Roseman en la correlación de la solubilidad de la indometacina en mezclas cosolventes 1,4-dioxano + agua. La correlación de la solubilidad se estudió en función de la temperatura y la composición cosolvente. Los dos modelos requieren únicamente los valores de solubilidad en los solventes puros a todas las temperaturas de interés. Los valores calculados se desvían significativamente de los experimentales en muchos casos.

Tensile strength study of the abdominal wall following laparotomy synthesis using three types of surgical wires in Wistar rats

PURPOSE: To study the tensile strength of the abdominal wall following laparotomy synthesis utilizing three types of surgical wires. METHODS: Thirty Wistar rats were randomized into three groups of ten rats each. Each group underwent a 3cm-laparotomy which was closed with 3-0 polyglactin 910, polyglecrapone and catgut wires. After 63 days, euthanasia was performed and part of the abdominal wall was removed with which a strip was produced measuring 2.0 cm in length by 6.0 cm in width comprising the abdominal muscles with the implanted mesh. The sample was fixed in a mechanical test machine in which constant force was applied contrary to the tissue strips. Maximum force was considered, expressed in Newton, until full rupture of the tissue occurred. The non-parametrical Kruskal - Wallis test was used for the statistical analysis, admitting p<0.05. RESULTS: The average strength of the catgut group was slightly lower (33.50 N) than that of the polyglactin group (34.23 N), the difference not being statistically significant (p=0.733). The polyglecaprone group was the one which presented the lowest strength value of all three wires analyzed (29.86 N). No statistical difference was obtained when comparing the strength values of the polyglecaprone group and the catgut group (p=0.06 ). However, when the polyglecaprone group was compared to the polyglactin 910 group no statistical difference was obtained (p=0.029). CONCLUSION: The polyglactin wire presented the highest tensile strength among the three wires analyzed, such value being statistically significant when polyglactin was compared to the polyglecaprone wire.

OBJETIVO: Estudar a resistência tênsil da parede abdominal após síntese de laparotomia utilizando três tipos de fios cirúrgicos. MÉTODOS: Trinta ratos da linhagem Wistar randomizados em três grupos de dez exemplares cada um. Em cada grupo fez-se uma laparotomia de dois centímetros que foi fechada com fios 3-0 de poliglactina 910, poliglecaprone e categute. Após 63 dias, foi feita a eutanásia e retirou-se uma área da parede abdominal com a qual fez-se uma tira medindo 2,0 cm de comprimento por 6,0 cm de largura englobando os músculos abdominais com a tela implantada. A amostra foi fixada em máquina de ensaios mecânicos na qual se aplicou força constante contrária às tiras de tecido. Foi considerada a força máxima expressa em Newton até ocorrer a ruptura total da amostra. Para a análise estatística, utilizou-se teste não paramétrico de Kruskal - Wallis admitindo-se p<0,05. RESULTADOS: A média de resistência do grupo categute foi ligeiramente menor (33.50 N) ao da poliglactina (34.23 N), sendo essa diferença não estatisticamente significativa (p=0,733). O grupo poliglecaprone foi o que apresentou menor resistência entre os três fios analisados (29.86 N). Comparando as resistências do grupo poliglecaprone ao grupo categute não se obteve significância estatística (p=0,06). Entretanto quando o grupo poliglecaprone foi comparado à poliglactina 910 houve significância estatística (p=0,029). CONCLUSÃO: O fio de poliglactina apresentou a maior resistência tênsil dentre os três fios analisados, sendo esta estatisticamente significativa quando comparado ao fio de poliglecaprone.

Lignin concentration in oat (Avena byzantina L. ) aerial part as measured by four analytical methods

The current analytical methods to quantify lignin in forages are not satisfactory. A spectrophotometric method, the acetyl bromide lignin(ABL), has been employed to determine lignin concentration in forages; however, it suffers from the lack of an ideal standard with which the optical density readings of samples are compared to. A lignin, extracted from the plant with a solution of acidic dioxane, was employed to build a calibration curve for this method. This procedure was then compared with other methods (acid detergent lignin - ADL, Klason lignin – KL and potassium permanganate lignin – PerL) to determine lignin content on different fractions (stem, leaf and whole plant) of eight oat cultivars (Avena byzantina L.). There was no agreement among the four methods. In general, ABL and KL methods yielded thehighest values while ADL method yielded the lowest, particularly for the young plants. Lignin concentration was higher in the stem fractionas compared to leaf. It was detected influence of maturity stage in the investigated samples. It is concluded that the ABL method employingas standard lignin extracted with acidic dioxane has potential to be employed as a method to determine lignin concentration.

Os métodos analíticos para quantificar a concentração de lignina atualmente em uso não se tem mostrado satisfatórios. Um método espectrofotométrico, a lignina brometo de acetila (LBA) tem sido empregado para determinar o teor de lignina em plantas forrageiras; entretanto, padece da inexistência de um padrão de referência ideal, com o qual as leituras de densidade óptica das amostras são comparadas. Uma lignina, extraída da planta com solução ácida dedioxano, foi empregada para a construção de uma curva de calibração para o método em questão. Este procedimento foi comparado com outros métodos (lignina detergente ácido - LDA, lignina Klason –LK e lignina permanganato de potássio - LPer) na estimativa do teor de lignina em diferentes frações vegetais (caule, folha e parte aérea) de oito cultivares de aveia (Avena byzantina L.). Não houve concordância de valores entre os quatro métodos analíticos. Num âmbito geral,LBA e LK forneceram as maiores estimativas enquanto a LDA resultounos menores valores, particularmente nas amostras de plantas mais jovens. A concentração de lignina foi mais elevada na fração caule do que na folha. Foi detectado efeito da maturidade nas amostras analisadas. Conclui-se que o método LBA usando como padrão de referência a lignina extraída com dioxano ácido tem potencial para ser empregado nas determinações dos teores de lignina.

Estudo clínico e histopatológico da reacão tecidual às suturas interna e externa dos fios monofilamentares de nylon e poliglecaprone 25 em ratos / Clinical and histopathological study of tissue reactivity to monofilament suture materials: nylon and poliglecaprone 25 in rats

OBJETIVOS: Neste estudo realizamos a análise clínica e histopatológica da reacão tecidual dos fios de nylon e poliglecaprone 25 monofilamentares nas suturas interna e externa em ratos. MÉTODOS: Foram utilizados 40 Rattus norvegicus (Wistar) machos. O ato operatório consistiu de incisão e divulsão dos planos muscular e cutâneo realizadas na região posterior das coxas dos animais. As suturas internas e externas da coxa direita foram realizadas com o fio de nylon nº5-0, e na coxa esquerda aplicamos o poliglecaprone 25 nº5-0. Os animais foram divididos em 4 grupos (n=10) de acordo com o tempo pós-operatório G1 (7 dias), G2 (14 dias), G3 (21 dias) e G4 (28 dias). Para a avaliacão cínica foi considerada a ocorrência de deiscência, de exsudato e edema. Na análise histopatológica objetivou-se avaliar reacão inflamatória, células gigantes de corpo estranho, proliferacão fibroblástica e fibrose. RESULTADOS: Clinicamente, não foram observadas alteracões nos grupos estudados. Histopatologicamente a reacão inflamatória, presenca de células gigantes de corpo estranho, proliferacão fibroblástica e fibrose foram maiores nas suturas internas realizadas com Nylon. Nas suturas realizadas com poliglecaprone 25 essa reacão declinou com o passar do tempo pós-operatório. CONCLUSAO: De acordo com a metodologia empregada podemos concluir que as suturas externas realizadas com nylon induziram menor reacão tecidual, enquanto que nas suturas internas este fio contribuiu para perpetuar a reacão tecidual. As suturas externas realizadas com poliglecaprone 25 apresentaram maior reacão tecidual, e suturas internas realizadas com o mesmo fio a reacão tecidual declinou na medida em que o fio estava sendo absorvido.

Comparative study of tissue response to polyglecaprone 25, polyglactin 910 and polytetrafluorethylene suture materials in rats

The authors evaluated the biocompatibility of three suture materials, polyglecaprone 25, polyglactin 910 and polytetrafluorethylene, implanted into subcutaneous tissue in the dorsal region of 20 Wistar albinus rats. After periods of 2, 7, 14 and 21 days, the rats were sacrificed and the specimens were processed for routine histotechnical analysis and stained with hematoxylin and eosin. The rate of fibrosis, angioblastic and fibroblastic proliferation, and also the intensity of inflammation were observed with the optic microscope. The results showed that polyglecaprone 25 suture material induced a mild inflammatory reaction, followed by polyglactin 910 and polytetrafluorethylene, respectively. Such biological behavior must be considered during the selection of the suture material to be used in oral surgery.