Gastroretentive floating microspheres have a potential for enhancing the bioavailability and controlled delivery of drugs. The present study involves development of rifampicin floating microspheres in order to increase t...Gastroretentive floating microspheres have a potential for enhancing the bioavailability and controlled delivery of drugs. The present study involves development of rifampicin floating microspheres in order to increase the gastric retention time. The microspheres were prepared by solvent evaporation technique and characterized for particle size, shape, zeta-potential, entrapment, and release kinetics. The developed systems were almost spherical in shape. The entrapment efficiency was found to be 86.34%. The percentage buoyancy after 8 hours was found to be 61.06. The prepared microspheres exhibited prolonged drug release in gastric medium and hence could be utilized for sustained delivery of anti-tubercular drugs.
OBJECTIVES: To investigate the cardioprotective effect of polymerized human placenta hemoglobin (PolyPHb) for acute myocardial ischemia rat heart. METHODS: Myocardial infarcts (MI) model was set up in SD rats by permanen...OBJECTIVES: To investigate the cardioprotective effect of polymerized human placenta hemoglobin (PolyPHb) for acute myocardial ischemia rat heart. METHODS: Myocardial infarcts (MI) model was set up in SD rats by permanent ligation of the left anterior descending coronary artery (LDA). The rats were divided randomly into 3 groups with each group of 20 rats: (A) the control group with the administration of Ringer's lactated solution at a dose of 2.5ml/kg); (B) PolyPHb group, PolyPHb solution at a dose of 0.16g Hb/kg and (C), PolyPHb+CAT+SOD group, PolyPHb solution at a dose of 0.16g Hb/kg and catalase (CAT) solution and superoxide dismutase (SOD) solution at a dose of 1681 U/kg and 528000 U/kg, respectively. Each rat received treatments via caudal vein, once a day for 7 days. Qualitative evaluations were made based on the reading of cardiac troponin T (cTnT), the myocardial infarction size (MIS) derived from the staining of myocardium tissue, and the pathological changes in infarct area. The ischemia changes of cardiomyocytes were determined by haematoxylin - basic fuchsin - picric acid (HBFP) staining and the apoptosis of cardiomyocytes were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay (TUNEL). RESULTS: Compared to the control group, PolyPHb greatly decreased the cTnT (p < 0.05), MIS (p < 0.05), and the size of myocardial ischemia (p < 0.05). PolyPHb + CAT + SOD decreased the △ST change (P < 0.05), cTnT (P < 0.01), MIS (p < 0.05), the pathological scores (p < 0.01), the size of myocardial ischemia (p < 0.01), and the apoptosis level (p < 0.01). CONCLUSION: Our study demonstrated that adding PolyPHb improves cardiac functional recovery and reduces myocardial infarction of rat heart.
PEG-Alb represents a new class of low viscogenic plasma expanders that achieve super perfusion in vivo by mimicking the vasodilatory influence of high viscogenic plasma expanders. PEGylation-engineered structure of PEG a...PEG-Alb represents a new class of low viscogenic plasma expanders that achieve super perfusion in vivo by mimicking the vasodilatory influence of high viscogenic plasma expanders. PEGylation-engineered structure of PEG albumin can be envisaged as a deformable molecular domain around the rigid central protein core. The correlation between the structure of PEG-shell in terms of packing of the PEG inside the PEG shell and PEGylation induced plasma expander (PE)-like properties of albumin has been investigated as a function of the number and length of the PEG-chain. The increase in molecular radius of albumin on PEGylation is non-linear as a function of the number of PEG chains conjugated. The packing density of PEG within the PEG-shell is an inverse correlate of PEG-chain size; i.e. the shorter chains pack more compactly than the longer ones. The PEGylation induced increase in the viscosity and COP of albumin is an exponential correlation of the number of ethylene oxide units (-CH(2)-CH(2)-O-) conjugated and is also a function of the PEG-chain length. At equivalence of PEG mass conjugated, the viscosity and COP of PEG-albumin adducts correlate inversely with packing density of PEG. All PEGylated albumins are not equivalent on the basis of total PEG mass conjugated. Accordingly, the structure of PEG albumin and its solution properties can be engineered to optimize a given total PEG mass for the application of PEG albumin as a resuscitation fluid. The extension arms minimize the influence of PEG shell on the structure of the protein core. We speculate that EAF-PEGylation is a preferable platform for PEGylation of protein therapeutics and is expected to generate products with better therapeutic efficacy.
We have previously reported that derivatization of hemoglobin with periodate-modified sugar derivatives such as oxidized adenosine triphosphate (oATP) leads to an increase in prooxidant reactivity at the heme. Here, we r...We have previously reported that derivatization of hemoglobin with periodate-modified sugar derivatives such as oxidized adenosine triphosphate (oATP) leads to an increase in prooxidant reactivity at the heme. Here, we report that copolymerization of hemoglobin with serum albumin alleviates this problem completely, to the extent where the copolymer even has a slightly lower autooxidation rate compared to native hemoglobin. A similar, although not as potent, effect is obtained when hemoglobin is derivatized with oATP in the presence of small-molecule antioxidants instead of albumin.
In this study, inkjet bio-printing has been used to produce miniaturized alginate microcapsules. A parametric study using subsequent Taguchi L(18) (3(1) × 2(7)) and L(16) (4(5)) designs was performed to elucidate the eff...In this study, inkjet bio-printing has been used to produce miniaturized alginate microcapsules. A parametric study using subsequent Taguchi L(18) (3(1) × 2(7)) and L(16) (4(5)) designs was performed to elucidate the effect of inkjet parameters on microcapsule size. A 120-minute pilot run using the optimal waveform parameters and 0.5% alginate ink yielded a throughput of 1.8×10(6) microcapsules/hr, averaging 40 μm in diameter. Real-time stable jetting conditions were confirmed visually by the generation of a single droplet with a straight trajectory and non-fluctuating Ohnesorge numbers. The rate of stirring of the cross-linking CaCl(2) solution determined scaffold vs. single vesicle formation.
Artif Cells Blood Substit Immobil Biotechnol
· 2011 Jun · PMID 21574914
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Polyhemoglobin-superoxide dismutase-catalase-carbonic anhydrase (PolyHb-SOD-CAT-CA) is a therapeutic antioxidant that also transports both oxygen and carbon dioxide. This is formed by crosslinking Hb with SOD, CAT, and C...Polyhemoglobin-superoxide dismutase-catalase-carbonic anhydrase (PolyHb-SOD-CAT-CA) is a therapeutic antioxidant that also transports both oxygen and carbon dioxide. This is formed by crosslinking Hb with SOD, CAT, and CA using glutaraldehyde. Crosslinking stroma free Hb from red blood cell (rbc) reduces CA activity to 55%. Addition of more CA resulted in a preparation with the same CA activity as RBC. PolyHb in the complex acts as a buffer to prevent large pH changes as carbon dioxide is converted to carbonic acid. We then prepare and optimize a novel PolyHb-SOD-CAT-CA, a therapeutic antioxidant that also transports both oxygen and carbon dioxide.
A glucose oxidase-based biosensor was developed for the determination of α-amylase activity. The determination method is based on monitoring the decrease in dissolved oxygen concentration related to the starch concentrat...A glucose oxidase-based biosensor was developed for the determination of α-amylase activity. The determination method is based on monitoring the decrease in dissolved oxygen concentration related to the starch concentration, for which starch gives a reaction with α-amylase. Optimization parameters, including glucose oxidase amount, gelatin amount, and glutaraldehyde percentage for cross-linking, were investigated. The effects of pH, buffer system, and temperature on the biosensor system were also investigated. The biosensor had a linear relation to α-amylase activity and good measurement correlation between 0.66 and 9.83 U/ml. In sample analysis studies, α-amylase activity in baker's yeast was determined by the biosensor.
This study aims to estimate the effects of using a portion of a nerve trunk to repair itself and the injured nerve simultaneously. Proximal 1/2 median nerve served as donor nerve to repair the distal 1/2 median and whole...This study aims to estimate the effects of using a portion of a nerve trunk to repair itself and the injured nerve simultaneously. Proximal 1/2 median nerve served as donor nerve to repair the distal 1/2 median and whole ulnar nerve. Four months postoperation, the number of myelinated axons and nerve conduction velocities of the distal half median and ulnar nerve were (2033 ± 135 and 24.6 ± 5.3 m/s) and (1138 ± 228 and 30.3 ± 7.2 m/s). It suggests that using a portion of a nearby nerve truck to reconstruct itself and the injured nerve simultaneously is a practical method for severe peripheral nerve injury.
Fibers comprised of reconstituted type I collagen were prepared by a gravity filament forming process and crosslinked with 0.1% glutaraldehyde. These fibers have a crosslinking index of about 90% (89.89 ± 1.82%) with hig...Fibers comprised of reconstituted type I collagen were prepared by a gravity filament forming process and crosslinked with 0.1% glutaraldehyde. These fibers have a crosslinking index of about 90% (89.89 ± 1.82%) with higher denature temperature (74.43 ± 0.08°C) as compared to that without glutaraldehyde treatment (52.1 ± 0.17°C). The ultimate tensile strength of the collagen fibers increases from 99.4 ± 12.9 to 174.4 ± 9.0 MPa after glutaraldehyde-crosslinking. L929 fibroblast cells were seeded and cultured using these newly developed collagen fibers. The fibroblast cells proliferated well and covered all surface areas of the collagen fiber. These collagen fibers have a great potential for application in 3-D tissue engineering.
Abstract: An ascorbate oxidase purified from the green fruit of zucchini squash (Cucurbita pepo medullosa) was immobilized photochemically on a polyethylene disc with 85% retention of initial activity of free enzyme. The...Abstract: An ascorbate oxidase purified from the green fruit of zucchini squash (Cucurbita pepo medullosa) was immobilized photochemically on a polyethylene disc with 85% retention of initial activity of free enzyme. The optimum pH (5.5) was unchanged, while K(m) was decreased. The polyethylene discs were employed for determination of ascorbic acid in serum and foodstuffs. The working linear range was 2.8 μM to 16 μM. The mean value of ascorbic acid in serum as measured by the method was 0.16 mg/dl in males and 0.209 mg/dl in females. The immobilized enzyme was used 100 times over 4 months, when stored at 4°C.
Encapsulation of cells in polymeric shells allows for separation of biological material from produced factors, which may find biotechnological and biomedical applications. Human T-lymphocyte cell line Jurkat as well as r...Encapsulation of cells in polymeric shells allows for separation of biological material from produced factors, which may find biotechnological and biomedical applications. Human T-lymphocyte cell line Jurkat as well as rat pancreatic islets were encapsulated using LbL technique within shells of polyelectrolyte modified by incorporation of biotin complexed with avidin to improve cell coating and to create the potential ability to elicit specific biochemical responses. The coating with nano-thin modified shells allowed for maintenance of the evaluated cells' integrity and viability during the 8-day culture. The different PE impact may be observed on different biological materials. The islets exhibited lower mitochondrial activity than the Jurkat cells. Nevertheless, coating of cells with polyelectrolyte modified membrane allowed for functioning of both model cell types: 10 μm leukemia cells or 150 μm islets during the culture. Applied membranes maintained the molecular structure during the culture period. The conclusion is that applied modified membrane conformation may be recommended for coating shells for biomedical purposes.
Herein, we describe a non-conventional method for immobilization of enzymes onto different solid surfaces using ultrasound as a source of energy. When horseradish peroxidase (HRP) was taken on the surface of an activated...Herein, we describe a non-conventional method for immobilization of enzymes onto different solid surfaces using ultrasound as a source of energy. When horseradish peroxidase (HRP) was taken on the surface of an activated support and allowed to float on a sonicator bath operating at a frequency of 40 KHz, it readily started binding itself to the surface. Maximum binding was observed in 10 min whereas a control experiment carried out similarly without ultrasound waves showed insignificant immobilization. Ultrasound wave-mediated immobilization is rapid and reproducible and is better suitable for versatile applications in different fields, including fabrication of enzyme-based biosensors or bioreactors.
Zhu H, Dang X, Yan K
… +6 more, Dai P, Luo C, Ma J, Li Y, Chang TM, Chen C
Artif Cells Blood Substit Immobil Biotechnol
· 2011 Jun · PMID 21381891
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The objective of the present study is to evaluate the pharmacodynamic properties of polymerized porcine hemoglobin (pPolyHb) in an exchange transfusion model. Each of two groups of rats received a volume of pPolyHb or he...The objective of the present study is to evaluate the pharmacodynamic properties of polymerized porcine hemoglobin (pPolyHb) in an exchange transfusion model. Each of two groups of rats received a volume of pPolyHb or hetastarch that equalled 120-140% of estimated total blood volume (70 ml/kg) exchange transfusion. The results showed pPolyHb retained hemodynamic stability and exhibited superior volume expansion capability. Furthermore, pPolyHb effectively reverse anaerobic metabolism caused by a large amount of volume exchange. In comparison with hetastarch, pPolyHb increased blood oxygen content and tissue oxygenation. All these properties contribute to a higher effectiveness in sustaining the lives of rats in pPolyHb group.
Human plasma fraction IV is an intermediate precipitate during the production of human serum albumin using cold ethanol method. Haptoglobin locates in this fraction can be purified for various applications. A new process...Human plasma fraction IV is an intermediate precipitate during the production of human serum albumin using cold ethanol method. Haptoglobin locates in this fraction can be purified for various applications. A new process integration of polyethylene glycol (PEG) precipitation and ion-exchange chromatography (IEC) was developed for purification of haptoglobin, which could effectively purify the haptoglobin from 16.6% to 95%. The recovery of the new process was 58.2% in comparison to 30.3% of the conventional affinity chromatography. Furthermore, 175 mg haptoglobin production in a scaled-up process showed the method to be simple, fast, and low-cost.
β-galactosidase splits lactose into glucose and galactose. Because of its biotechnological interest, we presented a biosensor system in order to monitor β-galactosidase activity. Immobilization steps of the biosensor wer...β-galactosidase splits lactose into glucose and galactose. Because of its biotechnological interest, we presented a biosensor system in order to monitor β-galactosidase activity. Immobilization steps of the biosensor were identified by cyclic voltammograms and electrochemical impedance spectroscopy. β-galactosidase was voltammetrically detected at about +150 mV (vs. Ag/AgCl) in citrate buffer solution (0.05 M, pH 4.8). The linear response for β-galactosidase detection was in the range of 0.0118 U mL(-1)to 0.47 U mL(-1)and a shorter response time of ∼50 s. Our results demonstrated the biosensor's electrochemical properties and analytical characteristics were very useful and effective for monitoring of β-galactosidase activity.
Abstract: In this paper, a new viewpoint on the activity determination of β-galactosidase is reported. Glucose oxidase was directly immobilized on a glassy carbon electrode and mediated by ferrocene. The biosensor's perf...Abstract: In this paper, a new viewpoint on the activity determination of β-galactosidase is reported. Glucose oxidase was directly immobilized on a glassy carbon electrode and mediated by ferrocene. The biosensor's performance was based on mediated electron transfer by ferrocene, which reduced via glucose oxidase reaction. In this reaction, substrate of glucose oxidase, glucose was provided by the activity of β-galactosidase in the sample. The parameters of the fabrication process for the electrode were optimized. Experimental conditions influencing the biosensor performance, such as pH, ferrocene and lactose concentrations, and temperature, were investigated and assessed. Finally, the biosensor was successfully applied to determination of β-galactosidase activity of artificial intestinal juice.
We have developed a strategy to immobilize β-galactosidase as a model enzyme by using polymeric supports having Schiff bases, which were prepared from (aminomethyl)polystyrene and 2-phenlyindole-3-carboxaldehyde by conde...We have developed a strategy to immobilize β-galactosidase as a model enzyme by using polymeric supports having Schiff bases, which were prepared from (aminomethyl)polystyrene and 2-phenlyindole-3-carboxaldehyde by condensation. β-galactosidase was immobilized onto the new polymer supports via covalent bonds. The influence of temperature, pH, reusability, and storage capacity on the free and immobilized β-galactosidase was investigated. Our results indicate that the (aminomethyl)polystyrene with Schiff bases is most suitable for the immobilization of β-galactosidase. These kinds of new supports can be used for the immobilization of β-galactosidase due to their strong storage capacity and reusability.
Injection of endothelial progenitor cells (EPCs) into arteries for cell therapy is a promising field in regenerative medicine. However, adhesion of EPCs during capillary passage is restricted, and non-adhering cells are...Injection of endothelial progenitor cells (EPCs) into arteries for cell therapy is a promising field in regenerative medicine. However, adhesion of EPCs during capillary passage is restricted, and non-adhering cells are lost into circulation. Here we demonstrate that it is possible to achieve a three- to sevenfold higher rate of EPC adhesion to endothelium and extracellular matrix molecules after short-term activation with phorbol myristate acetate (PMA). In addition, differentiation and toxicity analyses of PMA activated EPCs showed no impact on cell differentiation and negligible impact on cell survival.
The intraperitoneal instillation of perfluorocarbons augmented systemic oxygenation and was protective in mesenteric ischemia-reperfusion and experimental lung injury. To study biocompatibility and potential anti-inflamm...The intraperitoneal instillation of perfluorocarbons augmented systemic oxygenation and was protective in mesenteric ischemia-reperfusion and experimental lung injury. To study biocompatibility and potential anti-inflammatory effects of intraperitoneal perfluorocarbons, we evaluated the influence of perfluorohexane and/or inflammatory stimuli on human mesothelial cells in vitro. Perfluorohexane exposure neither impaired cell viability nor induced cellular activation. TNFα enhanced ICAM-1 expression, which was not attenuated by simultaneous perfluorohexane treatment. Concentration of intracellular surfactant protein A tended to be higher in perfluorohexane treated cells compared to controls. Our in vitro data add further evidence that intraperitoneal perfluorocarbon application is feasible without adverse local effects.