Heparin is biocompatible and can induce differentiation of human dental pulp cells.

AIM: To investigate the biocompatibility, osteogenic bioactivity and mRNA expression of the osteo/odontogenic markers bone morphogenetic protein 2 (BMP-2), osteocalcin (OC) and alkaline phosphatase (ALP), induced by heparin in human dental pulp cells (hDPCs). METHODOLOGY: hDPCs were exposed to the heparin, and cell viability was assessed by 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT), and cell death was evaluated by flow cytometry. Osteogenic bioactivity was evaluated by the alkaline phosphatase (ALP) assay, and the detection of calcium deposits by alizarin red staining (ARS). The gene expression of BMP-2, OC and ALP was quantified with real-time PCR. Statistical analysis was performed with ANOVA and Bonferroni or Tukey post-test and t-test (α = 0.05). RESULTS: Heparin had no cytotoxic effect and did not induce apoptosis. After 3 days, heparin had significantly higher ALP activity in comparison with the control (P < 0.05). Heparin had a significant (P < 0.05) stimulatory effect on the formation of mineralized nodules. BMP-2 and OC mRNA expressions were significantly higher in cells exposed to heparin than control group after 1 day (P < 0.05). CONCLUSIONS: Heparin was biocompatible in hDPCs, induced osteogenic bioactivity and enhanced mRNA expression of osteo/odontogenic markers BMP-2 and OC. These results suggest that heparin has potential to induce osteo/odontogenic cell differentiation of hDPCs.

Polymorphism of the ITS-2 region of the ribosomal DNA of the Triatominae Rhodnius domesticus, R. pictipes, R. prolixus and R. stali.

The polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP) was used to compare Rhodnius domesticus (Neiva & Pinto), R. pictipes (Stal), R. prolixus (Stal) and R. stali (Lent, Jurberg & Galvão) (Hemiptera: Reduviidae). The enzyme BstUI differentiated R. domesticus, R. pictipes and R. prolixus, and HhaI differentiated R. domesticus, R. pictipes and R. stali. With the fingerprinting analysis generated by these two enzymes, it was possible to clearly identify all four species in the study.

Strains of Xylella fastidiosa rapidly distinguished by arbitrarily primed-PCR.

Genomic DNAs isolated from strains of Xylella fastidiosa that caused citrus variegated chlorosis, coffee leaf scorch, Pierce's Disease of grapevine, and plum leaf scorch were analyzed by arbitrarily primed polymerase chain reaction. Purified DNA was amplified under nonstringent conditions with single primers 21 nucleotides (nt) long. Thirty-nine amplification products were observed that were useful to distinguish among the strains and to derive a similarity matrix and construct a phenogram showing possible relationships among the strains. Strains isolated from diseased coffee and citrus in Brazil were closely related to each other (coefficient of similarity of 0. 872), but only distantly related to a strain isolated from diseased grapevine in the USA (coefficient of similarity of 0.650). Strains of Xylella fastidiosa isolated from diseased plums in the USA and Brazil clustered with strains from different hosts isolated from their respective countries of origin. Thus, there may be two quite dissimilar clusters of strains of Xylella fastidiosa, one in North America and the other in South America. Each cluster contains strains that can cause disease in plum. The methods described provide a convenient and rapid method to distinguish between strains of Xylella fastidiosa that cause diseases of coffee and citrus in the same region of Brazil. This has not been possible previously. This will potentially enable the two strains to be distinguished in alternate hosts or in insect vectors.

[Immunological aspects of the phenoloxidase enzymatic system of Schistosoma mansoni]. / Aspectos imunológicos do sistema enzimático fenoloxidase de Schistosoma mansoni.

The phenol oxidase enzymatic system (EC 1.10.3.1, EC 1.10.3.2) is widespread in different species of the animal and vegetal kingdom. Despite its importance in the eggshell formation of the trematodes phenol oxidase (PO) has been little studied in these organisms, mainly in S. mansoni. This report presents the initial results concerning the immunization of rabbits with PO of S. mansoni and mushroom tyrosinase. The immunological analysis done by means of double immunodifusion (Ouchterlony) and immunoelectrophoresis techniques revealed some immunological identity between the PO of males and females. It was not seen cross reaction between the antisera against PO and tyrosinase, what suggests that the antigenic determinants of both enzymes are different in spite of their catalytic sites being similar, since they act over the same substrate. The results reported here represent a first step in way to obtain the PO isoenzymes in their pure form and should open new insights for further studies on the molecular mechanisms involved in the sclerotization process of the S. mansoni eggshell.

South American rattlesnake venom: its hemolytic power.

The hemolytic power of rattlesnake venom (Crotalus durissus terrificus) was studied. A high percentage of sample with negative hemolytic power was detected when sheep red blood cells were used. A large number of venoms with hemolytic power, though with a low hemolysis percentage, were detected when liquid, recently extracted venom was used. When crystallized venom was used under the same experimental conditions, a higher percentage of positivity for hemolysis was obtained. When the results obtained on agar plates were compared to those obtained in test tubes, a large number of animals with a higher percentage of hemolysis were detected, though this value was not proportional to the number of animals showing positive plate hemolysis. When the hemolytic power of these venoms was tested on human red blood cells, a large percentage of animals with venoms having a low hemolytic power was also detected. Hemolytic power was much greater when human red blood cells were tested with crystallized venom. The preparation of red blood cells also had an important effect and the use of red blood cells from defibrinated blood is recommended. We conclude that rattlesnake venom has hemolytic power that increases when the venom is crystallized. Red blood cells should be properly prepared for the lysis reactions. We suggest that the lytic power of the venom is related to venom concentration and to the purity of its fractions.