Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Carbohydr Res ; 531: 108893, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37429228

RESUMEN

An acid stable α-galactosidase was produced and purified from mannolytic fungal strain, Penicillium aculeatum APS1. Enzyme was produced using wheat bran and copra cake moistened with corn steep liquor by solid state fermentation. APS1αgal having molecular weight of 65.4 kDa was purified to electrophoretic homogeneity by three phase partitioning and gel permeation chromatography with high enzyme recovery. APS1αgal was found to be maximally active at 55 °C and pH 4.5, having high stability at acidic pH. Thermal stability and thermal inactivation kinetics of APS1αgal were also studied. APS1αgal was found to effectively hydrolyse oligosaccharides as well as polysaccharides having α-1,6 linked galactose. Abolishment of enzyme activity in N-brommosuccinimide revealed an important role of tryptophan residue in catalysis. APS1αgal had shown outstanding tolerance to NaCl and proteases. MALDI-TOF MS/MS analysis indicated that enzyme is probably a member of family GH27. Synergistic interaction between APS1αgal and ß-mannanase for hydrolysis of galactomannan was very clear and maximum 2.0° of synergy was found under simultaneous mode of action. This study reports a new source of α-galactosidase with biochemical properties suitable for applications in food and feed industries.


Asunto(s)
alfa-Galactosidasa , beta-Manosidasa , beta-Manosidasa/metabolismo , Hidrólisis , alfa-Galactosidasa/química , Espectrometría de Masas en Tándem , Concentración de Iones de Hidrógeno , Estabilidad de Enzimas , Especificidad por Sustrato , Cinética
2.
World J Orthop ; 14(4): 207-217, 2023 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-37155513

RESUMEN

BACKGROUND: Radiocarpal dislocations are rare but potentially devastating injuries. Poorer outcomes are associated with inadequate or lost reduction, such as ulnar translocation, but no consensus exists on the ideal fixation technique. Dorsal bridge plate fixation has been described for various settings in the treatment of complex distal radius fractures and can be fixed distally to the second or third metacarpal, but its application for radiocarpal dislocations has not been established. AIM: To determine whether distal fixation to the second or third metacarpal matters. METHODS: Using a cadaveric radiocarpal dislocation model, the effect of distal fixation was studied in two stages: (1) A pilot study that investigated the effect of distal fixation alone; and (2) a more refined study that investigated the effect of described techniques for distal and proximal fixation. Radiographs were measured in various parameters to determine the quality of the reduction achieved. RESULTS: The pilot study found that focusing on distal fixation alone without changing proximal fixation results in ulnar translocation and volar subluxation when fixing distally to the second metacarpal compared with the third. The second iteration demonstrated that anatomic alignment in coronal and sagittal planes could be achieved with each technique. CONCLUSION: In a cadaveric radiocarpal dislocation model, anatomic alignment can be maintained with bridge plate fixation to the second metacarpal or the third metacarpal if the described technique is followed. When considering dorsal bridge plate fixation for radiocarpal dislocations, the surgeon is encouraged to understand the nuances of different fixation techniques and how implant design features may influence proximal placement.

3.
3 Biotech ; 13(3): 107, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36875958

RESUMEN

In past several years, mannanases has attracted many researchers owing to its extensive industrial applications. The search for novel mannanases with high stability still continues. Present investigation was focused on purification of extracellular ß-mannanase from Penicillium aculeatum APS1 and its characterization. APS1 mannanase was purified to homogeneity by chromatography techniques. Protein identification by MALDI-TOF MS/MS revealed that the enzyme belongs to GH family 5 and subfamily 7, and possesses CBM1. The molecular weight was found to be 40.6 kDa. The optimum temperature and pH of APS1 mannanase were 70 °C and 5.5, respectively. APS1 mannanase was found to be highly stable at 50 °C and tolerant at 55-60 °C. The enzyme was very sensitive to Mn+2, Hg+2 and Co+2 metal ions and stimulated by Zn+2. Inhibition of activity by N-bromosuccinimide suggested key role of tryptophan residues for catalytic activity. The purified enzyme was efficient in hydrolysis of locust bean gum, guar gum and konjac gum and kinetic studies revealed highest affinity towards locust bean gum (LBG). APS1 mannanase was found to be protease resistant. Looking at the properties, APS1 mannanase can be a valuable candidate for applications in bioconversion of mannan-rich substrates into value-added products and also in food and feed processing.

4.
Prep Biochem Biotechnol ; 53(6): 599-609, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36129679

RESUMEN

Present study aims at sustainable utilization of sugarcane bagasse (SCB) for production of valuable prebiotic xylooligosaccharides (XOS) along with second generation ethanol. Fractionation of SCB into hemicellulose rich liquid fraction and cellulose rich solid residue was achieved using alkaline treatment. Carbohydrate rich precipitate obtained from liquid fraction was utilized for XOS production using inhouse produced endoxylanase. XOS production from SCB xylan was optimized by employing response surface methodology. Under optimized conditions, maximum XOS yield was 227.72 mg/g of carbohydrate rich precipitates. The solid residue obtained after alkaline pretreatment was used for ethanol fermentation by prehydrolysis and simultaneous saccharification and fermentation (P-SSF) process using cellulolytic enzyme cocktail and Saccharomyces cerevisiae SM1. Maximum ethanol concentration, productivity and yield were 79.76 ± 0.16 g/L, 0.83 g/L/h and 69.38%, respectively by employing P-SSF process. Based on the experimental data it can be predicted that bioconversion of 100 g raw SCB can yield 6.26 g of XOS (DP 2-DP 5), 15.95 g ethanol and 1.44 g of xylitol. Present investigation reports an integrated process for effective bioconversion of SCB into value added products by maximum utilization of cellulosic and hemicellulosic fractions simultaneously using indigenously produced fungal enzymes.


Asunto(s)
Saccharum , Administración de Residuos , Celulosa/metabolismo , Etanol , Saccharum/química , Álcalis , Hidrólisis , Fermentación , Saccharomyces cerevisiae/metabolismo
5.
J Obstet Gynaecol India ; 72(Suppl 2): 363-365, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36457447
6.
Mycology ; 12(4): 325-340, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34900384

RESUMEN

Brown rot basidiomycetes are a principal group of wood-decaying fungi which degrade wood cellulose and hemicellulose by the combination of carbohydrate active enzymes and non-enzymatic oxidation reactions. Very scant information is available on carbohydrate active enzymes of brown rot fungi. In this context, present study focused on the production of cellulolytic-hemicellulolytic enzymes from newly isolated brown rot Fomitopsis meliae CFA 2. Under solid-state fermentation using wheat bran as the substrate Fomitopsis meliae CFA 2 was able to produce a maximum of 1391.12 ± 21.13 U/g of endoglucanase along with other cellulolytic and hemicellulolytic enzymes. Various fermentation parameters were optimised for enhanced production of endoglucanase by employing Plackett-Burman design followed by Box-Behnken design. A well-fitted regression equation with R2 value of 98.91% was attained for endoglucanase. The yield of endoglucanase was enhanced by 1.83-fold after executing statistical optimisation of various fermentative parameters. The newly isolated Fomitopsis meliae CFA 2 was found to be a potential producer of endoglucanase. Enzymatic saccharification of alkali-treated wheat straw and rice straw resulted in release of 190.8 and 318.8 mg/g of reducing sugars, respectively.

7.
Int J Biol Macromol ; 182: 1161-1169, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33892036

RESUMEN

Endoglucanases from glycoside hydrolase family 5 (GH5) are the key enzymes in degradation of diverse plant polysaccharides. Present study reports purification, characterization and partial sequencing of novel thermostable GH5 family endoglucanase from a newly isolated brown rot fungi Fomitopsis meliae CFA 2. Endoglucanase was purified 34.18 fold with a specific activity of 302.90 U/mg. The molecular weight of the endoglucanase was 37.87 kDa as determined by SDS PAGE. LC MS/MS analysis identified the protein to be a member of GH5_5 family. The temperature and pH optima for endoglucanase activity were 70 °C and 4.8, respectively. The enzyme catalyzed the hydrolysis of carboxymethyl-cellulose with a Km of 12.0 mg/ml, Vmax of 556.58 µmol/min/mg and Kcat of 129.41/sec. The enzyme was stimulated by Zn+2 and K+ metal ions and DTT. Half-life (t1/2) for endoglucanase was found to be 11.36 h with decimal reduction time (D) of 37.75 h at 70 °C. The activation energy for endoglucanase was found to be 30.76 kJ/mol (50 °C-70 °C). Looking at the results, the endoglucanase from Fomitopsis meliae CFA 2 seems to be a promising thermostable enzyme which may be applicable in applications like biomass hydrolysis.


Asunto(s)
Celulasa/metabolismo , Coriolaceae/enzimología , Biomasa , Celulasa/química , Electroforesis en Gel de Poliacrilamida , Peso Molecular , Espectrometría de Masas en Tándem
8.
J Reconstr Microsurg ; 37(4): 315-321, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-32892332

RESUMEN

BACKGROUND: Microvascular thrombosis has been associated with cytokine release and inflammatory syndromes which can occur as a result of blood transfusions. This phenomenon could potentially lead to complications in breast free flap reconstruction. The aim of this study was to evaluate the impact of perioperative blood transfusion in free flap breast reconstruction using large population analysis. METHODS: The American College of Surgeons National Quality Improvement Program database was queried for delayed free flap breast reconstructions performed in 2016. The study population was divided based on perioperative blood transfusion within 24 hours of the start of the operation. Propensity score matching analysis was used to ensure homogeneity between the two study groups. Primary outcome was unplanned return to the operating room (OR) within 30 days. Secondary outcomes were readmission and complications. RESULTS: A total of 1,256 patients were identified. Out of those, 91 patients received a perioperative blood transfusion. All the patients received only one unit of PRBC within the first 24 hours. Those patients were matched with similar patients who did not receive a transfusion on a ratio of 1:3 (273 patients). Patients who received a transfusion had a significantly higher incidence of reoperation (42 vs. 10%, p < 0.001). Patients who received a transfusion were more likely to return to the OR after 48 hours from the initial operation (13 vs. 5%, p = 0.001). All returns to the OR were due to flap-related complications. Perioperative blood transfusion increased the incidence of wound dehiscence (9 vs. 2%, p = 0.041) but had no protective effect on the development of other postoperative complications. CONCLUSION: Perioperative blood transfusion in free flap breast reconstruction is associated with an increased probability of flap-related complications and subsequent return to the OR without decreasing the probability of developing other systemic postoperative complications.


Asunto(s)
Colgajos Tisulares Libres , Mamoplastia , Transfusión Sanguínea , Humanos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/cirugía , Puntaje de Propensión , Estudios Retrospectivos , Factores de Riesgo
9.
Plast Reconstr Surg Glob Open ; 8(11): e3301, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33299727

RESUMEN

The SARS-CoV-2 pandemic resulted in the implementation of healthcare practice regulations and restrictions across the United States. To facilitate safe patient management practices for facial plastic and reconstructive surgeons, appropriate guidelines and recommendations should be followed. Guidelines and recommendations should include a synthesis of the best evidence available from public health authorities and respected members in the surgery community. This review contains evidence-based suggestions that prioritize the safety of healthcare professionals and patients to help guide facial and reconstructive surgeons toward safe patient management.

10.
Plast Reconstr Surg Glob Open ; 8(3): e2662, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32537330

RESUMEN

Perioperative liberal fluid resuscitation (LFR) can result in interstitial edema and venous congestion and may be associated with compromised perfusion of free flaps and higher incidence of wound complications. We hypothesized that restrictive intraoperative fluid resuscitation improves flap perfusion and lowers the wound complication rate in free flap breast reconstruction. METHODS: Patients undergoing free flap reconstruction of the breast from 2010 to 2018 were retrospectively reviewed. The study population was divided into 2 groups, LFR (≥7 ml/kg/h) and restrictive fluid resuscitation (RFR) (<7 ml/kg/h). Mean percutaneous oximetry readings of the flap over the first 24 hours were recorded. Primary outcome was development of any wound complication. Secondary outcomes were mean percutaneous oximetry readings within the first 24 hours, length of stay, and development of acute kidney injury. RESULTS: One hundred twenty-six patients were identified, with 41 patients undergoing LFR. The mean fluid received for the RFR group was 5.5 versus 10.2 ml/kg/h for the LFR group (P < 0.001). LFR resulted in a significantly higher incidence of wound complications (76% versus 15%, P < 0.001). The mean oximetry readings within 24 hours were significantly lower for the LFR group (41% versus 56%, P < 0.001). Urine output intraoperatively and within the first 24 hours was similar between the 2 groups. No patients developed acute kidney injury. CONCLUSION: RFR in free flap breast reconstruction is associated with increased flap perfusion and lower incidence of wound-related complications and should be considered whenever possible.

11.
Plast Reconstr Surg Glob Open ; 8(1): e2581, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32095396

RESUMEN

According to the American Society of Plastic Surgeons, the male to female ratio of plastic surgeons is approximately 5:1. As more surgical specialties are recruiting female residents, there has been an increase in the amount of females. We set out to examine the current trends in residency recruitment and whether a quantifiable gender bias exists. METHODS: A review of all the integrated plastic surgery programs within the United States was conducted. Data were collected regarding department or division status, the gender of the chairman and the program directors, the number of residents per year and gender of residents per year. The ratio of male to female residents was calculated. RESULTS: A total of 62 residency programs were identified. The vast majority had a male program director with only 8 female program directors identified. The mean ratio of female/male (F/M) residents overall was 1/1.2. Female program directors selected residents in the same ratio as their male counterparts [F/M ratio: 1/1.26 versus 1/1.18, p:0.813]. A linear logistic regression failed to identify the geographic location, department status, gender of the department chairman or the number of residents selected per year as predictors of higher F/M ratio. CONCLUSIONS: There are still fewer female program directors and residents in plastic surgery overall. However, neither was more likely to select a resident of their own gender. This analysis does not rule out the possible self-selection factor.

12.
Plast Reconstr Surg Glob Open ; 8(12): e3281, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33425595

RESUMEN

Clostridium difficile-associated infections (CDI) have a significant impact on morbidity and mortality of hospitalized medical and surgical patients. There is a paucity of data regarding the incidence, impact, and modifiable risk factors in the plastic surgery population. METHODS: The ACS NSQIP database was retrospectively queried for all cases performed by plastic surgeons during 2016. All plastic surgery cases, combined cases, demographics, and baseline clinical characteristics were extracted from the database. The study population was divided into 2 groups based on the development of CDI. Independent variables for development of CDI were identified. RESULTS: During the study period, a total of 29,256 patients underwent a procedure by plastic surgery, with the most commonly performed procedures involving the breast (58%) and trunk (14%). Only 44 patients developed post-operative CDI (0.1%). Factors independently associated with development of CDI were wound classification at the end of the surgery, COPD, procedures involving the trunk, and surgery for reconstruction of pressure ulcers. Outpatient surgery was associated with decreased odds of developing CDI [AOR (95% CI):0.2 (0.1, 0.4), adj P < 0.001]. Staying overnight did not increase the odds of developing CDI; however, staying for >1 day in the hospital was associated with an increased risk of CDI development [AOR (95% CI): 1.03 (1.01, 1.13), adj P = 0.001]. Combined cases, ASA, body mass index, diabetes, and active smoking were not associated with CDI. CONCLUSIONS: CDI are rare in the plastic surgery population and are most associated with trunk/decubitus ulcer reconstructions, inpatient hospital stay, and contaminated wounds. The patients that usually fit in these categories have acutely or chronically infected wounds, which are often treated with systemic antibiotics. For patient with decubitus ulcers and other trunk reconstruction, the guidelines for pre and post-operative systemic antibiotic usage is not well defined. For patients who have had trunk reconstruction, development of evidence-based antibiotic stewardship guidelines may help these patients by limiting antibiotic usage and thereby reducing the incidence of CDI.

13.
Breast J ; 25(2): 286-289, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30734417

RESUMEN

To assess the impact of internal mammary (IM) vessels radiation dose on autologous free-flap based breast reconstruction outcomes. We retrospectively evaluated the medical records of breast cancer patients who underwent mastectomy and free-flap breast reconstruction after postoperative radiation therapy (RT) to the breast/chest wall with (n = 9) or without (n = 11) electively including the IM lymph nodes. Twenty patients were included. Median age at diagnosis was 50 years (range, 33-63). The median time interval between the start of RT and reconstructive surgery was 16 months (range, 6-45). The maximal IM vessels dose was not associated with the risk of all complications (P = 0.44) or fat necrosis (P = 0.31). The mean IM vessels dose was not significant for the risk of all complications (P = 0.13) but was significant for fat necrosis (P = 0.04). A high mean IM vessels dose was related to the occurrence of fat necrosis.


Asunto(s)
Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Mamoplastia/efectos adversos , Glándulas Mamarias Humanas/irrigación sanguínea , Dosificación Radioterapéutica , Adulto , Anastomosis Quirúrgica , Vasos Sanguíneos/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Femenino , Colgajos Tisulares Libres , Humanos , Mamoplastia/métodos , Glándulas Mamarias Humanas/efectos de la radiación , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Factores de Tiempo
14.
Plast Reconstr Surg ; 141(4): 1063-1070, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29595742

RESUMEN

Because plastic surgery trainees generally spend the majority of their training in academic centers and may have minimal exposure to other practice models, it can be difficult to decide which is the best route to achieve satisfaction and success. Surgeons need to be aware of benefits and challenges associated with different practice models and with workplace factors in general that contribute to happiness at work. This article reviews common practice models and provide specific and practical advice for the female surgeon.


Asunto(s)
Selección de Profesión , Movilidad Laboral , Docentes Médicos , Satisfacción en el Trabajo , Médicos Mujeres , Práctica Privada , Cirugía Plástica , Docentes Médicos/educación , Docentes Médicos/organización & administración , Docentes Médicos/psicología , Femenino , Humanos , Liderazgo , Mentores , Médicos Mujeres/organización & administración , Médicos Mujeres/psicología , Práctica Privada/organización & administración , Sexismo , Cirugía Plástica/educación , Cirugía Plástica/organización & administración , Estados Unidos
15.
Int J Biol Macromol ; 109: 1260-1269, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29174354

RESUMEN

ß-Xylosidase plays an important role in xylan degradation by relieving the end product inhibition of endo-xylanase caused by xylo-oligosaccharides. ß-Xylosidase has a wide range of applications in food, feed, paper and pulp, pharmaceutical industries and in bioconversion of lignocellulosic biomass. Hence, in the present study focused on purification, biochemical characterization and partial sequencing of purified ß-xylosidase from xylanolytic strain Aspergillus niger ADH-11. Acetone precipitation followed by GPC using Sephacryl S-200 yielded 20.59-fold purified ß-xylosidase with 58.30% recovery. SDS-PAGE analysis of purified ß-xylosidase relieved a monomeric subunit with a molecular weight 120.48kDa. Kinetic parameters of purified ß-xylosidase viz Km, Vmax, Kcat and catalytic efficiency were assessed. Purified ß-xylosidase was additionally active on p-nitrophenyl-ß-d-glucopyranoside substrate also. Moreover, peptide mass fingerprinting analysis support our biochemical studies and showed that the purified protein is a novel ß-xylosidase with ß-glucosidase activity and belongs to the bi-functional GH3 superfamily. Besides, tolerance of purified ß-xylosidase towards glucose and xylose was also assessed.


Asunto(s)
Aspergillus niger/enzimología , Xilosidasas/química , Xilosidasas/metabolismo , beta-Glucosidasa/química , beta-Glucosidasa/metabolismo , Cromatografía en Gel , Activación Enzimática , Estabilidad de Enzimas , Concentración de Iones de Hidrógeno , Iones , Metales , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Relación Estructura-Actividad , Temperatura , Xilosidasas/aislamiento & purificación , beta-Glucosidasa/aislamiento & purificación
16.
Clin Plast Surg ; 44(3): 603-610, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28576249

RESUMEN

Severe pediatric burns require a multidisciplinary team approach at a specialized pediatric burn center. Special attention must be paid to estimations of total body surface area, fluid resuscitation and metabolic demands, and adequate analgesia and sedation. Long-term effects involve scar management and psychosocial support to the child and their family. Compassionate comprehensive burn care is accomplished by a multidisciplinary team offering healing in the acute setting and preparing the child and family for long-term treatment and care.


Asunto(s)
Quemaduras/terapia , Adolescente , Factores de Edad , Unidades de Quemados , Quemaduras/complicaciones , Quemaduras/metabolismo , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Cicatrización de Heridas
17.
3 Biotech ; 6(1): 62, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28330132

RESUMEN

The present study describes the rapid and efficient indirect lysis method for environmental DNA extraction from athalassohaline soil by newly formulated cell extraction buffer. The available methods are mostly based on direct lysis which leads to DNA shearing and co-extraction of extra cellular DNA that influences the community and functional analysis. Moreover, during extraction of DNA by direct lysis from athalassohaline soil, it was observed that, upon addition of poly ethylene glycol (PEG), isopropanol or absolute ethanol for precipitation of DNA, salt precipitates out and affecting DNA yield significantly. Therefore, indirect lysis method was optimized for extraction of environmental DNA from such soil containing high salts and low microbial biomass (CFU 4.3 × 104 per gram soil) using newly formulated cell extraction buffer in combination with low and high speed centrifugation. The cell extraction buffer composition and its concentration were optimized and PEG 8000 (1 %; w/v) and 1 M NaCl gave maximum cell mass for DNA extraction. The cell extraction efficiency was assessed with acridine orange staining of soil samples before and after cell extraction. The efficiency, reproducibility and purity of extracted DNA by newly developed procedure were compared with previously recognized methods and kits having different protocols including indirect lysis. The extracted environmental DNA showed better yield (5.6 ± 0.7 µg g-1) along with high purity ratios. The purity of DNA was validated by assessing its usability in various molecular techniques like restriction enzyme digestion, amplification of 16S rRNA gene using PCR and UV-Visible spectroscopy analysis.

18.
Ann Plast Surg ; 77(1): 122-8, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25144419

RESUMEN

Tissue-engineering scaffolds are often seeded with a single type of cell, but there has been more focus on cocultures to improve angiogenesis and bone formation for craniofacial applications. Investigation of bone-derived osteoblasts (OBs) is important because of the use of bone grafts and migration of OBs from native bone into constructs in vivo and therefore, their contribution to bone formation in vivo. The limitation of primary OBs has been their inability to mineralize without osteogenic factors in vitro. Through coculture of OBs and endothelial cells (ECs) and manipulation of the coculture ratio, mineralization can be achieved without osteogenic media or additional growth factors, thus enhancing their utility for tissue-engineering applications. An optimal ratio of EC/OB for vasculogenesis and mineralization has not been determined for human primary cells. Human umbilical vein ECs were cultured with normal human primary OBs in different EC/OB ratios, namely, 10:1, 5:1, 1:1, 1:5, and 1:10 with EC and OB monocultures as controls. The number of vasculogenic networks in a collagen matrix was highest in ratios of 5:1 and 1:1. ECs lined up and formed capillary-like networks by day 10, which was not seen in the other groups. On polystyrene, cells were cocultured with ECs and OBs in direct contact (direct coculture) or separated by a transwell membrane (indirect coculture). At day 21, Alizarin Red staining showed mineralization on the 1:5 and 1:10 direct coculture ratios, with 1:5 having more mineralization nodules present than 1:10. No mineralization was seen in other direct coculture ratios or in any of the indirect coculture ratios. Alkaline phosphatase secretion was highest in the 1:5 direct coculture group. Vascular endothelial growth factor secretion from OBs was present in the 1:5 and 1:10 direct coculture ratios at all time points and inhibited after day 1 in other coculture groups. To improve vasculogenesis, cocultures of primary human ECs and OBs in ratios of 5:1 should be used, but to improve bone formation, the 1:5 direct coculture ratio results in most mineralization.


Asunto(s)
Regeneración Ósea/fisiología , Calcificación Fisiológica/fisiología , Células Endoteliales de la Vena Umbilical Humana/fisiología , Neovascularización Fisiológica/fisiología , Osteoblastos/fisiología , Ingeniería de Tejidos/métodos , Técnicas de Cocultivo , Humanos , Andamios del Tejido
19.
Biomed Res Int ; 2014: 353845, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25093166

RESUMEN

Pentyl valerate was synthesized biocatalytically using Candida rugosa lipase (CRL) immobilized in microemulsion based organogels (MBGs). The optimum conditions were found to be pH 7.0, temperature of 37 °C, ratio of concentration of water to surfactant (Wo) of 60, and the surfactant sodium bis-2-(ethylhexyl)sulfosuccinate (AOT) for MBG preparation. Although kinetic studies revealed that the enzyme in free form had high affinity towards substrates (K(m) = 23.2 mM for pentanol and 76.92 mM for valeric acid) whereas, after immobilization, the K(m) values increased considerably (74.07 mM for pentanol and 83.3 mM for valeric acid) resulting in a slower reaction rate, the maximum conversion was much higher in case of immobilized enzyme (~99%) as compared to free enzyme (~19%). Simultaneous effects of important parameters were studied using response surface methodology (RSM) conjugated with Box-Behnken design (BBD) with five variables (process parameters), namely, enzyme concentration, initial water content (Wo), solvent used for MBG preparation, substrate ratio and time, and response as the final product formation, that is, pentyl valerate (%). The MBGs were reused for 10 consecutive cycles for ester synthesis. Efficacy of AOT/isooctane as dehydrating agent for extracting excess water from MBGs was found to exert a positive effect on the esterification reaction.


Asunto(s)
Candida/enzimología , Enzimas Inmovilizadas/química , Lipasa/química , Valeratos/síntesis química , Emulsiones/química , Esterificación , Ésteres/síntesis química , Ésteres/química , Geles/síntesis química , Geles/química , Cinética , Valeratos/química , Valeratos/uso terapéutico , Agua/química
20.
J Craniofac Surg ; 25(4): 1504-9, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24943502

RESUMEN

Critical-sized bone defects can lead to significant morbidity, and interventions are limited by the availability and donor-site morbidity of bone grafts. Polymer scaffolds seeded with cells have been explored to replace bone grafts. Adipose-derived stem cells have shown great promise for vascularization and osteogenesis of these constructs, and cocultures of differentiated stem cells are being explored to augment vessel and bone formation. Adipose-derived stem cells were differentiated into endothelial cells and osteoblasts, and in vitro studies showed increased proliferation of cocultured cells compared with undifferentiated adipose-derived stem cells and monocultures of endothelial cells and osteoblasts. The cells were seeded into polylactic acid gas-plasma-treated scaffolds as cocultures and monocultures and then implanted into critical-sized rat calvarial defects. The cocultures were in a 1:1 osteoblast to endothelial cell ratio. The increase in proliferation seen by the cocultured cells in vitro did not translate to increased vascularization and osteogenesis in vivo. In vivo, there were trends of increased vascularization in the endothelial cell group and increased osteogenesis in the osteoblast and endothelial monoculture groups, but no increase was seen in the coculture group compared with the undifferentiated adipose-derived stem cells. Endothelial cells enhance vascularization and osteoblast and endothelial cell monocultures enhance bone formation in the polymer scaffold. Predifferentiation of adipose-derived stem cells is promising for improving vascularization and osteogenesis in polymer scaffolds but requires future evaluation of coculture ratios to fully characterize this response.


Asunto(s)
Tejido Adiposo/citología , Regeneración Ósea/fisiología , Células Madre/fisiología , Ingeniería de Tejidos/métodos , Andamios del Tejido , Animales , Materiales Biocompatibles/química , Densidad Ósea/fisiología , Enfermedades Óseas/cirugía , Capilares/patología , Diferenciación Celular/fisiología , Proliferación Celular , Células Cultivadas , Técnicas de Cocultivo , Células Endoteliales/fisiología , Ácido Láctico/química , Neovascularización Fisiológica/fisiología , Osteoblastos/fisiología , Osteogénesis/fisiología , Gases em Plasma/química , Poliésteres , Polímeros/química , Ratas , Ratas Endogámicas Lew , Cráneo/irrigación sanguínea , Cráneo/cirugía , Andamios del Tejido/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA