Viscoelasticity of frozen/thawed egg yolk as affected by salts, sucrose and glycerol

Based on dynamic rheological measurements, sucrose, glycerol and magnesium chloride (MgCl2) prevented egg yolk gelation at concentrations of 2% and higher, These additives showed improved cryoprotectant effects as their concentrations were increased, Sodium chloride (NaCl) at higher than 2% also prevented gelation but at 10%, it caused a considerable increase in viscosity of unfrozen yolk, Calcium chloride (CaCl2) showed an opposite effect, promoting protein coagulation before freezing, Samples with 2% CaCl2 gelled completely after 36h at -24 degrees C, Before freezing, potassium chloride (KCl) in the range 2-10% had an effect similar to that of NaCl, However, after freezing its effect changed, Yolk with 2% KCl, frozen 36h at -24 degrees C, showed very elastic behavior.

Crytallization and high-resolution X-ray diffraction data collection of an Asp49 PLA(2) from Bothrops jararacussu venom both in the presence and absence of Ca2+ ions

Snake venom PLA(2)s have been extensively studied due to their role in mediating and disrupting physiological processes such as coagulation, platelet aggregation and myotoxicity. The Ca2+ ion bound to the putative calcium-binding loop is essential for hydrolytic activity. We report the crystallization in the presence and absence of Ca2+ and X-ray diffraction data collection at 1.60 Angstrom (with Ca2+) and 1.36 Angstrom (without Ca2+) of an Asp49 PLA(2) from Bothrops jararacussu venom. The crystals belong to orthorhombic space group C222(1). Initial refinement and electron density analysis indicate significant conformational. changes upon Ca2+ binding. (C) 2004 Elsevier B.V. All fights reserved.

Effect of different glycosaminoglycans in a guinea-pig carotid-artery thrombosis model

Heparin is the most frequently used drug for the prevention and treatment of thrombosis. Its use, however, is restricted by its side-effects. To study the efficacy of other glycosaminoglycans that could substitute heparin in the management of arterial thrombosis, 60 guinea-pigs were randomly allocated into 6 groups: G1= control, G2= heparin (150 IU/kg), G3= heparan sulfate from beef pancreas (2.5 mg/kg), G4= heparan sulfate from beef lung (2.5 mg/kg), G5= N-acetylated heparan from beef pancreas, G6= dermatan sulfate from beef intestine (2.5 mg/kg). Ten minutes after intravenous injection of the drugs, thrombosis was induced by the injection of a 50% glucose solution into a segment of the right carotid artery isolated between 2 thread loops during 10 minutes. Three hours later the artery was re-exposed and if a thrombus was present it was measured, withdrawn and weighed. Thrombin time and activated partial thromboplastin time were measured in all animals. Thrombus developed in 90% of the animals in the control group, 0% in G2 and G3, 62.5% in G4, 87.5% in G5 and G6. Only in the animals treated with heparin the coagulation tests were prolonged. In conclusion, in the used dose only the heparan sulfate from beef pancreas presented an antithrombotic effect similar to heparin in this experimental model.

Heparina e K3EDTA como anticoagulantes para tambaqui (Colossoma macropomum Cuvier, 1816)

The efficacy of sodium heparin and tripotassium EDTA as anticoagulant and their effect on the hematological parameters of tambaqui (Colossoma macropomum) were evaluated in this study. Ten fish weighing 384.9 +/- 85.71 g and measuring 27.90 +/- 2.10 cm were used for heparin 5.000 IU, heparin 100 IU and K3EDTA 10% evaluation. Clotting inhibition after 10 h, erythrogram and osmotic fragility of erythrocytes were observed. The results were submitted to variance analysis and means compared by Tukey test (P < 0.05). Heparin 5.000 IU, heparin 100 IU and K3EDTA 10% were effective in preventing coagulation for more than 10 h. However, tripotassium EDTA caused hemolysis since first moments. In erythrogram there was no difference (P > 0.05) in erythrocyte count, hematocrit, hemoglobin and MCHC. on the other hand, an increase in MCV (P < 0.05) in samples kept with K3EDTA10% was observed. This anticoagulant provoked a significant increase (P < 0.01) in the osmotic fragility of erythrocytes when compared to pure heparin, diluted heparin and the control group. Heparin as an anticoagulant is more appropriate for tambaqui since it was effective in preventing coagulation for more than 10 h, without causing hemolysis, changes on hematological parameters or osmotic fragility of erythrocytes.

Functional and structural analysis of two fibrinogen-activating enzymes isolated from the venoms of Crotalus durissus terrificus and Crotalus durissus collilineatus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sulfonation and anticoagulant activity of botryosphaeran from Botryosphaeria rhodina MAMB-05 grown on fructose

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Studies on the activation of the pre-kininogenin-kininogenin (pre-kallikrein-kallikrein) system by sulfated polysaccharides and kaolin

The activation of pre-kininogenin to kininogenin (pre-kallikrein to kallikrein) is one of the steps in the series of reactions of a complex system, linked also to fibrinolysis and coagulation, that leads to kinin release in plasma (See Cochrane et al., 1976; Wuepper, 1976; Kaplan et al., 1976; Kaplan et al., 1976). For human plasma, a test using kaolin as activator and measuring kallikrein activity with the chromogenic substrate Chromozym PK (Nα-benzoyl-prolyl-phenylalanyl-arginyl-nitroanilide, Pentapharm, Basle) is routinely employed. The purpose of this paper is to further study the mechanism of this activation, by means of different activators and using as inhibitor hexadimethrine bromide (Polybrene). Besides kaolin, sulfated polysaccharides, such as heparin and cellulose sulfate are able to activate pre-kininogenin to kininogenin. Hexadimethrine as expected, inhibited the activation by heparin and also that by cellulose sulfate. The activation by kaolin however followed a different pattern suggesting, at least partially, a different mode of action of this activator. © 1979.

Characterization of the colloidal products of pentacarbonyliron oxidation

Pentacarbonyliron was oxidized with H2O2, in organic solvents, to give colloidal sols. The aqueous-ethanolic sol is highly stable and undergoes thermally-reversible coagulation. Its solid phase was found to be a non-crystalline Fe (III) hydroxoacetate which is transformed to α-Fe2O3 when heated to 300°C. Iron-bound acetate groups are assumed to have a major role in the sol stability, by preserving the amorphous solid phase. Dry hydroxoacetate particles were heated under vacuum; scanning electron microscopy revealed that these particles coalesce and grow, as in a sintering process but at low temperatures (100-250°). © 1987.

Fresh autogenous rib cartilage graft to the malar process of rats with and without removal of the perichondrium: a histological study.

A comparison was made of autogenous grafts of rib cartilage with and without removal of the perichondrium, applied to the malar process of rats. Seventy-two male albino rats were divided into two groups according to the kind of graft received by each animal. The experimental periods were 5, 10, 20, 30, 60 and 120 postoperative days. The results showed that, in the control group, the grafts maintained their vitality for the whole experimental period and the perichondrium was biologically integrated into the host bed. Appositional growth was also observed. The treated animals showed intense resorption of the grafts and more intense bone neoformation. The newly formed bone was in intimate contact with the graft in both groups.

Interference of the blood clot on granulation tissue formation after tooth extraction. Histomorphological study in rats.

The interference of a blood clot in the first postoperative hours of dental extraction wounds was studied in rats. Sixty male albino rats were divided into two groups: Group I, immediately after extraction of right maxillary incisor the gingival mucosa was approximated and sutured; Group II, after 6 to 8 minutes postoperatively the blood clot was removed with saline irrigation and absorbent paper cones. The mucosa was then approximated and sutured. Six animals in each group were sacrificed after 12 hours, 1, 4, 7 and 10 days. There was a profound delay in healing in Group II since, although a new blood clot was later formed, it was not organized. The quality and the constitution, maintenance and retraction of the clot are the regulating factors in connective tissue formation during alveolar healing.

Time evolution of the structure function and dynamical scaling in porous SnO2 dry gels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

OLEO ESSENCIAL EM ALGUMAS ESPECIES DE EUCALYPTUS

In this work we used leaves of four species of Eucalyptus - E. bicostata Maiden, E. deanei Maiden, E. dunnii Maiden and E. viminalis Labill, grown in Colombo, Parana State, Brazil. Preliminary studies were done, in the following sequence: botanic identification, olfactory research, extraction and purification of the essential oil of each species. The physical and chemical tests done were the following: relative density, refractive index, optical rotation, solubility, coagulation point and cineol percentage. The essential oils analysed through gaseous chromatography, presented the following cineol percentage: E. bicostata Maiden - 26.92%, E. deanei Maiden - 70.21%, E. dunnii Maiden - 53.16% and E. viminalis Labill - 23.05%.

EXAFS and XRD Study of the Structural Evolution during Isothermal Sintering of SnO2 Xerogels

The formation of an ordered (crystalline) phase during isothermal sintering of SnO2 monolithic xerogels, at 200, 250, 300, 400, 500, 600 and 700°C, has been analyzed by the combined use of EXAFS and XRD techniques. For the desiccated gel (110°C), EXAFS results show the formation of small microcrystallites with the incipient cassiterite structure. Between 110 and 250°C, the dehydratation reaction leads to an amorphization evidenced by a decrease of the long and short range crystallographic order. It is due to fissure formation in the xerogel network. For higher temperatures, a continuous coagulation of the crystallites occurs, leading to grain growth. Grain and pore growth obeys the same kinetic relation, so that the microstructure grows by simple enlargement while its morphology is static.

The interaction between vitamin K nutriture and warfarin administration in patients with bacterial overgrowth due to atrophic gastritis

Atrophic gastritis patients have intestinal bacterial overgrowth which could produce menaquinones. The aim of this study was to evaluate the interaction between a diet low in phylloquinone and minidoses of warfarin in subjects with and without bacterial overgrowth. Subjects with atrophic gastritis (indicated by serum pepsinogen ratio) and healthy volunteers were studied while fed a restrictive phylloquinone diet and while receiving a minidose of warfarin. Coagulation times, serum osteocalcin, serum undercarboxylated osteocalcin, plasma phylloquinone, plasma K-epoxide, plasma undercarboxylated prothrombin (PIVKA)-II and urinary gamma-carboxyglutamic acid (Gla) were measured. At baseline, there were no differences between groups for any variable measured. Comparisons between baseline and post intervention in both groups, showed significant increases in circulating levels of K-epoxide, PIVKA II and undercarboxylated osteocalcin. However, no differences were observed when comparisons were made between groups. Our data do not support the hypothesis that bacterial synthesis of menaquinones in patients with bacterial overgrowth due to atrophic gastritis confers considerable resistance to the effect of warfarin.

Biocompatibility of an adhesive system applied to exposed human dental pulp

Human pulp tissue was directly capped with All Bond 2, or calcium hydroxide and evaluated 7, 30, or 60 days after the procedures. Histological analysis was performed to assess the inflammatory cell response, tissue disorganization, dentin bridging, and the presence of bacteria. At 7 days, with All Bond 2 capping, there was a large area of neutrophilic infiltrate underlying the pulp capping material, and the death of adjacent odontoblasts, was observed. However, with time, the neutrophilic reaction was replaced by fibroblastic proliferation with macrophages and giant cells surrounding globules of resin scattered in the coronal pulp tissue. The persistent inflammatory reaction and hyaline alteration of extracellular matrix inhibited complete pulp repair or dentin bridging. In contrast, at 7 days, the pulp tissue capped with calcium hydroxide exhibited odontoblast-like cells organized underneath coagulation necrosis. Pulp repair evolved into apparent complete dentin bridge formation at 60 days. All Bond 2 did not appear to allow any pulp repair and does not appear to be indicated for direct pulp capping of human teeth. Copyright © 1999 by The American Association of Endodontists.