Gelatin Group Research Articles

Chemical Cross-Linking Gelatin with Natural Phenolic Compounds as Studied by High-Resolution NMR Spectroscopy

Cross-linking gelatin with natural phenolic compound caffeic acid (CA) or tannic acid (TA) above pH 9 resulted in formation of insoluble hydrogels. The cross-linking reactivity was controlled by variation of pH, the concentration of the gelatin solution, or the amount of CA or TA used in the reaction. The cross-linking chemistry was studied by high-resolution NMR technique in both solution and solid state via investigation on small molecular model systems or using (13)C enriched caffeic acid (LCA) in the reaction with gelatin. Direct evidence was obtained to confirm the chemical reactions occurring between the phenolic reactive sites of the phenolic compounds and the amino groups in gelatin to form C-N covalent bonds as cross-linking linkages in gelatin matrix. The cross-linked network was homogeneous on a scale of 2-3 nm. The cross-linking resulted in a significant decrease in the molecular mobility of the hydrogels, while the modulus of the films remained at high values at high temperatures.

The ameliorating effect of preoperative loading infusion with 4% succinylated gelatin solution on hemorheology of gastric cancer patients during perioperative period

Objective To investigate the effect of loading infusion with succinylated gelatin(GEL) solution before surgery on hemorheology of patients with gastric cancer during perioprative period. Methods Forty patients undergoing gastric cancer radical surgery were randomly divided into 2 groups (n=20): GEL solution group (GEL group) and Ringer's Lactated solution group(RL group). Twenty people received health examination were selected as normal control group. The two kinds of solution were respectively infused at a dose of 15 ml/kg over a period of 30 rain before surgery (loading infusion, LI). Blood samples were taken for determination of hemorheology variables before LI(T_0, baseline), the end of LI(T_1), 1 h after the end of Ll(T_2)and 1 h after the end of surgery (T_3). Results The blood viscosity, plasma viscosity, erythrocyte aggregation index (EAI)and fibrinogen were higher than those in normal control group (P<0.05). The blood viscosity, plasma viscosity, EAI, fibrinogen and Hct decreased significantly as compared to the baseline values at T_0 in GEL group(P<0.05). The blood viscosity at low shear rate and EAI increased significantly as compared to the baseline values at T_0 in RL group (P<0.05). The blood viscosity, plasma viscosity, EAI, fibrinogen and Hct were lower than those in RL group at T_2 and T_3(P<0.05). Conclusion Blood of patients with gastric cancer presentes hyperviscosity state.GEL solution can ameliorate hemorheology variables and alleviate hyperviscosity state during perioperative period. Key words: Gelatin; Fluid therapy; Hemorheology; Gastric neoplasms

Prospective observational study for perioperative volume replacement with 6% HES 130/0,42, 4% gelatin and 6% HES 200/0,5 in cardiac surgery

BackgroundThe constantly growing amount of different kinds of colloid fluids necessitates comparative investigations with regards to the safety and effectivity in clinical use of these preparations. Hence we compared three colloid fluids in an observational study. The objective was the exploration of the influence of these three colloids on blood coagulation, hemodynamics and renal function of the cardiac surgical patient.MethodsWe included 90 patients undergoing an elective open-heart surgery with the use of the heart-lung machine and observed them consecutively. Group 1 [gelatin 4% (n = 30)], Group 2 [HES 200/0,5 (n = 30)] and Group 3 [HES 130/0,42 (n = 30)]. We measured the perioperative volume replacement, the administration of blood- and coagulation-products, the application of catecholamines, the renal function, blood gas and the platelet aggregation using multiplate electrode analyzer (Multiplate®, Dynabyte medical, Munich, Germany).ResultsThe gelatin-group needed significantly more norepinephrine than the HES 130/0.42 group. The responsible surgeon considered the blood coagulation in the HES 200/0.5 group most frequently as impaired. Furthermore we saw a significant decrease in platelet function in the HES 200/0.5 group when performing the multiplate®-analysis (ADP-and COL-test). HES 130/0.4 as well as gelatin 4% showed no significant change in platelet function. The gelatin-group and the HES 200/0.5 needed significantly more aprotinine than the HES 130/0.4 group. We saw no significant difference with regards to administration of blood and coagulation products between the three groups. The urinary excretion during the intervention was significantly higher in the HES 200/0.5 group and in the gelatin group than in the HES 130/0.4 group.ConclusionsOur results confirm the lower stabilizing effect of gelatin on circulation during fluid resuscitation. The blood coagulation was mostly impaired due to HES 200/0.5 confirmed by the multiplate®-analysis as well as by different clinical findings.

Characteristics of Cholesterol-Grafted Gelatin Micelles

Gelatin, a hydrophilic protein derived from collagen, has been widely used in drug delivery system because of its biocompatibility and biodegradability. However, its high water solubility limited its interaction with hydrophilic drugs. The current works propose a method to improve surface activity of gelatin by modifying it into an amphiphilic molecule via conjugating with cholesterol. High contents of cholesterol were conjugated to amino groups (-NH2) of gelatin using N,N’-Disuccinimidyl carbonate. Cholesterol contents were varied from 100% by mole of free -NH2 group in gelatin. The reduction of free -NH2 groups on gelatin determined by 2,4,6-trinitrobenzenesulfonic acid (TNBS) decreased with the increases of cholesterol used in the conjugation. The percentage of reduction of -NH2 content was 74.63 by mole respectively. Hydrophilicity/hydrophobicity changes were evaluated from water and ethylene glycol contact angles. The conjugated-gelatin were aggregated to form micelles at a critical micelle concentration (CMC) of 8 mg/ml in DI water (pH 5), determined by surface tension testing. Average size of the micelles were in range of 459.05±54.59 nm. The micelles were tested for curcumin entrapment for a cancer research.

Influence of colloid infusion on coagulation during off-pump coronary artery bypass grafting

This study was conducted to determine the influence of colloid infusion on coagulation in patients undergoing off-pump coronary artery bypass grafting (OP-CABG). Thirty patients undergoing elective OP-CABG received medium molecular weight hydroxyethyl starch group I (MMW-HES 200/0.5), low molecular weight hydroxyethyl starch group II (LMW-HES 130/0.4) or gelatin group III (GEL) in a prospective randomized trial. Blood samples were assessed for hemoglobin (Hb), activated coagulation time (ACT), prothrombin time (PT), activated partial thromboplastin time (aPPT), platelet count, fibrinogen and von Willebrand factor (vWF) at specified intervals. Total volume of the colloid infused and postoperative chest-time drainage was also measured. There was a significant decrease in Hb, platelet count, fibrinogen levels in all these groups, which did not warrant blood transfusion. After the colloid infusion, vWF decreased significantly to 67% from baseline in group I as compared to 85 and 79% in group II and group III, respectively. vWF levels remained lower than the baseline value in the first 24 hours in group I, whereas this factor level increased above the baseline values in groups II and III, 6 hours postoperatively. Postoperative chest tube drainage in 24 hours was significantly higher in group I (856 ± 131 ml) as compared to group II (550 ± 124 ml) and group III (582 ± 159 ml). LMW-HES 130/0.4 was superior to MMW-HES 200/0.5 and gelatin in patients undergoing OP-CABG, in terms of better preservation of coagulation associated with enhanced volume effect.

Six percent hydroxyethyl starch 130/0.4 impacts differently on blood glucose than 4% gelatine in a swine model of mixed acidaemia

Tris-hydroxymethyl aminomethane can be used as a buffer in case of restricted ventilation, but hypoglycaemia is one adverse effect. The influence of a starch-based colloid [6% hydroxyethyl starch 130 kDa/0.4 (HES130)] vs. a gelatine-based colloid (4% polysuccinated gelatine) on blood glucose was investigated in a swine model of mixed acidaemia. Continuous colloid infusion was done in anaesthetized pigs with exogenously induced mixed acidaemia, which was maintained for 3 h. Pigs (approximately 40 kg, n = 6 in each group) were randomized to HES130 or 4% gelatine infusion (4 ml kg h(-1)). Infusion of an acid solution and low tidal volume ventilation induced mixed acidaemia. Treatment of mixed acidaemia with tris-hydroxymethyl aminomethane buffer, which is known to induce hypoglycaemia, prolonged anaesthesia, and volume support challenged the control of blood glucose. Hypoglycaemia was treated by individually dosed infusion of 5% glucose in sterile water. Bolus infusion of HES130 led to a moderate peak in blood glucose in four pigs. Four pigs in the 4% gelatine group and three in the HES130 group needed glucose infusion to prevent a drop in blood glucose levels below the set threshold (4 mmol l(-1)). The total amount of the glucose infusion was significantly lower in the HES130 group compared with the 4% gelatine group (100 vs. 295 ml per pig, median, P < 0.05). Generally, the HES130 pigs required glucose at later time points during anaesthesia. The first HES130 pig needed 5% glucose 2 h later than the first 4% gelatine pig to prevent a drop of blood glucose below 4 mmol l(-1). Volume support impacted specifically on blood glucose in this porcine model. Thus, an additional control of blood glucose seems recommendable whenever a change in the volume support occurs.

Is 6% Hydroxyethyl Starch 130/0.4 Safe in Coronary Artery Bypass Graft Surgery?

The aim of this study was to compare 6% hydroxyethyl starch 130/0.4 with 4% succinylated gelatin for priming the cardiopulmonary bypass circuit and as volume replacement in patients undergoing coronary artery bypass, in terms of postoperative bleeding, blood transfusion requirements, renal function, and outcome after surgery. Forty-five patients received 6% hydroxyethyl starch 130/0.4 (Voluven) and another 45 were given 4% succinylated gelatin (Gelofusine) as the priming solution for the cardiopulmonary bypass circuit as well as for volume replacement. Postoperative bleeding was quantified from the hourly chest drainage in the first 4 h and at 24 h postoperatively. The baseline characteristics of both groups were similar. In the hydroxyethyl starch group, the total amount of colloid used was 1.9 +/- 1.0 L, while the gelatin group had 2.0 +/- 0.7 L. There was no significant difference in hourly chest drainage between groups. Blood transfusion requirements, estimated glomerular filtration rate, extubation time, intensive care unit and hospital stay were similar in both groups. It was concluded that 6% hydroxyethyl starch 130/0.4 is a safe alternative colloid for priming the cardiopulmonary bypass circuit and volume replacement in patients undergoing coronary artery bypass surgery.

Effects of Local and Sustained Release of FGF, IGF, and GH on Germ Cells in Unilateral Undescended Testis in Rats

To evaluate the effects of the local release of fibroblast growth factor (FGF), insulin-like growth factor (IGF), and growth hormone (GH) on a germ cell population of ipsilateral undescended and contralateral descended testes of rats with a surgically created unilateral abdominal testis for 12 weeks and after the application of growth factors after orchidopexy. Forty 4-week old male Wistar albino rats were divided into 5 groups as follows: group 1, sham; group 2, gelatin; group 3, FGF; group 4, IGF; and group 5, GH. In the sham group, the right testis was exposed and sutured with 5-0 silk sutures. In groups 2-5, a right intra-abdominal testis was surgically created. After 12 weeks, orchidopexy was performed, and 1 cm(2) gelatin films were sutured to the right testes, either unloaded (group 2), or containing 2.5 microg FGF (group 3), 5 microg IGF (group 4), or 5 microg GH (group 5). After 30 days, both testes were removed for histopathologic investigation and DNA flow cytometry. The mean seminiferous tubular diameters (MSTDs), mean testicular biopsy scores (MTBSs), and percentages of haploid (1n) cells were calculated. Ipsilateral MSTD and MTBS significantly decreased in the gelatin and FGF groups compared with the sham, IGF, and GH groups. Contralateral MSTDs and MTBSs did not differ among groups. The haploid cell percentage significantly decreased in the ipsilateral and contralateral testes of the gelatin group compared with the sham, FGF, IGF, and GH groups. Local release of IGF and GH resulted in the preservation of germ cell histology in the ipsilateral testes of rats with a surgically created unilateral undescended testis for 12 weeks and after orchidopexy. The administration of IGF, GH, and FGF increased the haploid germ cell population in both ipsilateral undescended and contralateral descended testes.

Intraoperative Volume Replacement: Crystalloids Versus Colloids In Surgical Myocardial Revascularization Without Cardiopulmonary Bypass (CPB)

The use of crystalloids or colloids for volume replacement in large size surgeries is controversial. The objective of this study was to compare the effects of the intraoperative administration of crystalloids (normal saline - NS) with those of colloids (modified fluid gelatin) for surgical myocardial revascularization (SMR) without cardiopulmonary bypass (CPB). Forty patients undergoing SMR without CPB were randomly divided in two similar groups. The first group received modified fluid gelatin and NS and the second group received only NS. Urine output, hemoglobin level, intra- and postoperative bleeding, blood glucose levels, and intraoperative lactate in four distinct measurements were recorded. Postoperative morbidity and mortality, length of stay in the intensive care unit (ICU), and length of hospitalization were analyzed. Time to extubation in the gelatin group was 6.6 hours versus 7.3 hours in the NS group. The length of stay in the ICU was 2.4 days in the gelatin group versus 3.3 days in the NS group. The length of hospitalization was 10.3 days in the gelatin group versus 6.8 days in the NS group. The incidence of renal and respiratory complications, cardiac arrhythmias, myocardial infarctions, infections, reintubations, blood transfusions, and reoperation was the same in both groups. The use of colloids represented here by modified fluid gelatin associated with crystalloids or the use of crystalloids alone did not change the postoperative prognosis of patients undergoing SMR without CPB. Perhaps maintenance of the hemodynamic balance during the surgery is more important than the type of fluid administered.

Adding enzymatically modified gelatin to enhance the rehydration abilities and mechanical properties of bacterial cellulose

Bacterial cellulose (BC) possesses excellent water holding capacity. However, increased crystallization causes a decrease in the rehydration ability of dried BC. Due to its excellent hydrophilic properties, we used gelatin and its enzymatically modified form (EMG) to prepare BC nano-composites in an attempt to enhance the rehydration abilities properties of BC. The polar peptide fraction was increased by extended hydrolysis of fish gelatin in Alcalase. Peptides smaller than 10 kDa were obtained by hydrolysis at 50 °C for 20 min. Protein contents of composites prepared by immersing BC in 5% gelatin (Gelatin/BC) or EMG (EMG/BC) solution were 81% and 92%, respectively, both of which then formed high gelatin/BC composites (HGBC). The protein content of EMG/BC was higher than that of Gelatin/BC, as compared with low gelatin/BC composites (LGBC) that were formed by immersion in a corresponding 0.5% solution. Among both HGBC and LGBC composites, EMG/BC exhibited the best rehydration abilities. Freeze-dried EMG/BC also exhibited the fastest rehydration rate and the best ability to restore wet-type composites. Composite microstructures revealed that BC was enveloped by gelatin when non-polar EMG (NPEMG) and polar EMG (PEMG) entered the BC network and adsorbed onto cellulose ribbons. The microstructure of EMG/BC contained both PEMG/BC and NPEMG/BC structures. Gelatin hydrolysates, penetrating BC networks and forming stable composites, improved the rehydration ability of dried BC. The polar functional groups of gelatin and its hydrolysates represent the key factors contributing to the hydrophilic nature of composites.

Trabeculectomy and gelatin implants. A retrospective, long-term follow-up study.

In a retrospective follow-up study including 60 eyes with simple or capsular glaucoma, the results obtained by using a gelatin implant under the scleral flap during trabeculectomy were compared with those obtained without such implants. One month postoperatively the mean IOP was significantly lower in the gelatin group than in the control group (15.0 mmHg and 17.9 mmHg, respectively) (p = 0.024). At the long-term follow-up, however, the mean IOP in the two groups were very similar (13.6 mmHg and 14.8 mmHg, respectively).

Widespread and Early Tracheal Cartilage Regeneration by Synchronous Slow Release of b-FGF and BMP-2

Our previous studies have demonstrated that slow release of basic fibroblast growth factor (b-FGF) or bone morphogenetic protein 2 (BMP-2) induces cartilage regeneration. In the present study, we investigated whether synchronous slow release of b-FGF and BMP-2 would induce more widespread and earlier cartilage regeneration than that induced by each growth factor alone. A 1-cm defect was made in the mid-ventral portion of each of 10 consecutive tracheal rings. In four controls, the defect was left untreated. In the gelatin group (n = 4), empty gelatin sponge was implanted. In the b-FGF + BMP-2 group (n = 5), two gelatin sponges containing 100 microg of b-FGF or BMP-2 solution were implanted. After various periods, we euthanatized the dogs, and examined the implant sites. In the b-FGF + BMP-2 group, regenerated fibrous cartilage connected the host cartilage stumps and completely filled the defect between them at 1, 2, 3, and 12 months. Regenerated cartilage was covered by regenerated perichondrium originating from the host perichondrium, and showed neovascularization in the extracellular matrix. We succeeded in inducing more widespread and earlier cartilage regeneration using synchronous slow release of b-FGF and BMP-2 than that induced by release of each growth factor alone.

Effects of different culture conditions on isolation and expansion of stem cells from second-trimester amniotic fluids

To investigate the effects of different culture conditions on the isolation and expansion of stem cells from second-trimester amniotic fluids. Amniotic fluids were obtained from 15 pregnant women undergone amniocenteses for medical indications between 16 - 24 gestation weeks by transabdominal amniocenteses from September 2007 to June 2008. Amniotic fluids (10 - 20 ml) samples were collected and each was cultured under different conditions or groups. (1) Low-glucose DMEM (LD) medium supplemented with 10% of fetal bovine serum (group of 10%FBS); (2) LD medium with 20% of FBS (group of 20%FBS); (3) LD medium with 15% of FBS and 4 ng/ml of basic fibroblast growth factor (group of bFGF); (4) LD medium with 10% of FBS as well as the culture plate coated with gelatin (group of gelatin). The effects of different conditions were evaluated by comparing the number of primary colonies, the cell morphology and the ability of expansion. The isolated stem cells were identified by flow cytometry, RT-PCR and differentiation ability to adipocyte. (1) The success rates of primary culture of the group of 10%FBS, 20%FBS, bFGF and gelatin were 60%, 73%, 73% and 60% respectively (P > 0.05). The numbers of colonies were 0.9 +/- 0.5, 2.6 +/- 1.5, 2.9 +/- 1.5, 1.1 +/- 0.8 (P < 0.01 when group of 10%FBS and gelatin compared with group of 20%FBS and bFGF); among the primary colonies, fibroblast-like colonies accounted for 46%, 49%, 64%, 44% respectively (P > 0.05). (2) The second passage cells obtained from all of these four groups could differentiate into adipocyte after induction. (3) In the group of bFGF, stem cells were isolated from 5 samples and expanded to nearly 10(7) cells after 5 passages (P < 0.01 compared with other groups). (4) Karyotype were normal in all samples. (5) Stem cells from bFGF group showed positive expression of SSEA-4, Oct-4 and Nanog gene detected by flow cytometry and RT-PCR. Stem cells can be isolated from second-trimester amniotic fluids; moderate serum concentration and supplementation of bFGF can improve the efficiency of isolation and expansion of amniotic fluid of stem cells.

Phase behavior and properties of polyvinyl alcohol/gelatin blends with novel pH-dependence

A novel change of phase behavior and properties of polyvinyl alcohol (PVA)/gelatin blends as a function of pH was reported. The PVA/gelatin blends were found to be completely miscible in acidic condition (pH 8), and immiscible in neutral condition (pH was ca. 6). As a result, the membranes cast from acidic condition showed the highest tensile strength and the lowest alcohol vapor permeation (AVP) rate; those obtained from neutral condition showed the lowest tensile strength and highest AVP rate; the properties of membranes cast from basic condition lay in between. The interaction between PVA and gelatin was investigated via Fourier transform infrared spectrum (FTIR), differential scanning calorimetry (DSC), and Zetasizer measurement. The novel pH-dependence of the blends was ascribed to the protonation of amino groups of gelatin in acidic condition, which resulted in a strong electrostatic attraction between NH of gelatin and OH of PVA. The partial miscibility in basic condition was due to the ionization of carboxyl groups of gelatin, which caused a stretching of gelatin via electrostatic repulsive force and a breakage of the H-bonding among the molecular chains, leading to a limited interaction between PVA and gelatin and forming a partially miscible blend. In neutral conditions, there were almost no charges (very limited protonation and ionization) at the weak polyampholyte gelatin, and the strong H-bonding among gelatin molecules themselves or PVA molecules themselves caused the phase separation between gelatin and PVA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 239–247, 2009

Structural modifications of serum transthyretin in rats during protein‐energy malnutrition

Transthyretin (TTR) is a sensitive marker of protein-energy malnutrition and changes in serum and expression levels during protein and energy deficiency are well described. However, little is known about structural modifications of TTR during protein and/or energy deprivation. Therefore, the aim of this study was to determine the effects of protein inadequacies on post-translational modifications of TTR. For this purpose, male Wistar rats were fed a diet with either casein or gelatine as sole protein source subsequent to a protein wash-out period. Changes in TTR serum levels as well as other markers of nutritional status as body weight, food consumption, total serum protein and serum RBP4 levels as well as antioxidative capacity were determined. Post-translational modifications of TTR were examined by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) analysis. The rats from the gelatine group revealed a marked change in the post-translational modification pattern of TTR which was reflected by a significant elevation of sulfonated TTR and which was inversely correlated to the antioxidative capacity. Additionally, the elevation of sulfonated TTR was accompanied by a decrease in body weight and food consumption, low antioxidative capacity as well as a deprivation of serum TTR, RBP4 and total serum protein levels in the animals of the gelatine group. Protein-energy malnutrition leads therefore next to changes in TTR serum concentration, also to changes in the post-translational modification pattern of TTR. Such changes are probably induced by protein-energy malnutrition-driven oxidative stress and might be linked to alterations in protein function and stability.

Alteration of anion gap and strong ion difference caused by hydroxyethyl starch 6% (130/0.42) and gelatin 4% in children

Synthetic colloid administration is a common practice for preventing perioperative hypovolemia and consecutive circulatory failure in children. This prospective, randomized study was conducted to investigate the effects of two different unbalanced synthetic colloid solutions on acid-base equilibrium in children. Fifty pediatric patients (aged 0-12 years) scheduled for major pediatric surgery were randomized to receive either 10 ml x kg(-1) of 6% hydroxyethyl starch solution 130/0.42 (HES) or 4% modified fluid gelatin (GEL) to maintain adequate systemic hemodynamics. Before and after colloid administration, a blood sample was collected to analyze hemoglobin, hematocrit, electrolytes, and acid-base parameters. The anion gap and the strong ion difference (SID) were calculated using standard formulas. Both HES and GEL administration caused a significant increase in plasma chloride concentration (P < 0.01) and an accompanying decrease in SID (P < 0.01). In the HES group, the anion gap decreased significantly (P < 0.01) whereas the anion gap remained stable in the GEL group. In both groups, initial actual base excess and pH did not change significantly after colloid administration. Moderate intraoperative plasma replacement with unbalanced synthetic colloids HES and GEL leads to a decrease in SID and, in the case of HES, to a significant decrease in the anion gap in children. These alterations may result in a possible misinterpretation when the anion gap and SID are used for differential diagnosis of metabolic disturbances during major pediatric surgery.

Buffer capacity of 4% succinylated gelatin does not provide any advantages over acidic 6% hydroxyethyl starch 130/0.4 for acid-base balance during experimental mixed acidaemia in a porcine model

Four percent gelatine is an alkaline compound due to NH2 groups, whereas 6% hydroxyethyl starch 130/0.4 (HES130) has acidic features. We investigated whether these solutions lead to differences in acid-base balance in pigs during acidaemia and correction of pH. Anaesthetized pigs were randomized to HES130 or gelatine infusion (n = 5 per group). Animals received acid infusion (0.4 M solution of lactic acid and HCl diluted in normal saline) and low tidal volume ventilation (6-7 mL kg(-1), PaCO2 of 80-85 mmHg, pH 7.19-7.24). Measurements were made before and after induction of acidaemia, before and after correction of pH with haemofiltration (continuous venovenous haemofiltration) and tris-hydroxymethylaminomethane infusion. We measured parameters describing acid-base balance according to Stewart's approach, ketone body formation, oxygen delivery, haemodynamics, diuresis and urinary pH. Acid-base balance did not differ significantly between the groups. In HES130-treated pigs, the haemodilution-based drop of haemoglobin (1.4 +/- 1.0 g dL(-1), median +/- SD) was paralleled by an increase in the cardiac output (0.5 +/- 0.4 L min(-1). Lacking increases in cardiac output, gelatine-treated pigs demonstrated a reduction in oxygen delivery (149.4 +/- 106.0 mL min(-1)). Tris-hydroxymethylaminomethane volumes required for pH titration to desired values were significantly higher in the gelatine group (0.7 +/- 0.1 mL kg(-1) h(-1) vs. HES130: 0.5 +/- 0.2 mL kg(-1) h(-1)). The buffer capacity of gelatine did not lead to favourable differences in acid-base balance in comparison to HES130.

Effects of concentration on nanostructural images and physical properties of gelatin from channel catfish skins

Physical properties are crucial to gelatin utilization and the physical properties are determined by structure. Therefore, it is important to investigate the nanostructure and physical properties of gelatin over the full range of concentrations which are widely applied in research and industry. Nanostructure of gelatin can be investigated by atomic force microscopy (AFM). However, it is hard to obtain reliable AFM images of gelatin with high concentrations (1–6.67%). In this study, methods for imaging gelatin with high concentration were explored and developed, which mainly included six steps. Then the relationships among concentration, nanostructure and physical property of gelatin extracted from channel catfish skins ( Ictalurus punctatus) were studied. The high-resolution AFM images show fibril structure in gelatins with concentrations from 1% to 6.67%. However, in low concentrations (<1%), most nanostructures of gelatin were spherical aggregates and fibril structure only existed occasionally. Correspondingly, there were no significant differences of gel strength, texture profile and viscosity among several groups of gelatin when the concentration was lower than 1%, in contrast, these properties changed dramatically when the concentration was greater than 1%. It indicates that there must be some close relationships among concentration, nanostructure and physical property of gelatin. The illustration of nanoscale transition would help us understand the macroscale changes of physical properties.

Characterization of polyvinyl alcohol/gelatin blend hydrogel films for biomedical applications

AbstractIn the present investigation, attempt was made to prepare blend hydrogel by esterification of polyvinyl alcohol with gelatin. The blend hydrogel was further converted into films by the conventional solution‐casting method. These films were characterized by FTIR, DSC, and X‐ray diffraction studies. The refractive index and viscosity of different composition of the blends were measured in the solution phase of the material. The mechanical properties of the blend films were measured by tensile test. Swelling behavior of the blend hydrogel was also studied. The FTIR spectrum of the blend film indicated complete esterification of the free carboxylic group of gelatin. The DSC results indicate that the addition of gelatin with PVA changes the thermal behavior like melting temperature of PVA, which may be due to the miscibility of PVA with gelatin. The interaction of gelatin with PVA molecule changes the crystallite parameters and the degree of crystallinity. The crystallinity of the blend film was mainly due to gelatin. The comparison of viscosity indicated an increase in the segment density within the molecular coil. The results revealed the changes observed in the properties of the gel, and it enhances the gel formation at viscoelastic phase of the material. The blend film had sufficient strength and water‐holding capacity. The results obtained indicated that the blend film could be used for various biomedical applications such as wound dressing and drug‐delivery systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Is Sodium Alginate an Alternative Hemostatic Material in the Tooth Extraction Socket

SYNOPSIS Alginate has been used in wound dressing and tissue engineering. In this study, our designed alginate sponge was examined for use as an optimal occlusion material. Alginate powder was mixed in double-distilled water (3.0% w/v), sterilized and lyophilized to become a sponge. Sixty Wistar rats were undergone the right mandibular incisor extraction and divided into 3 groups: the first group received an alginate sponge; the second received a gelatin sponge; and the third was untreated. The mandibles were retrieved after 1, 2, 4 and 8 weeks and subjected for bleeding measurement, radiographic and histological analyses. Alginate and Gelatin groups showed significantly shorter bleeding time until hemostasis than control. In Alginate group, as well as the other groups, bone formation was observed from 2 weeks post operation. The extraction socket receiving alginate was finally filled with osteoblasts and bone, suggesting that alginate might be considered as a candidate for not only cartilage but bone generation.