Therapeutic potential of mesenchymal stem cells to treat Achilles tendon injuries.

Rupture of the Achilles tendon diminishes quality of life. The gold-standard therapy is a surgical suture, but this presents complications, including wound formation and inflammation. These complications spurred evaluation of the therapeutic potential of mesenchymal stem cells (MSCs) from adipose tissue. New Zealand rabbits were divided into 6 groups (three treatments with two time points each) evaluated at either 14 or 28 days after surgery: cross section of the Achilles tendon (CSAT); CSAT + Suture; and CSAT + MSC. A comparison between all groups at both time points showed a statistically significant increase in capillaries and in the structural organization of collagen in the healed tendon in the CSAT + Suture and CSAT + MSC groups at the 14-day assessment. Comparison between the two time points within the same group showed a statistically significant decrease in the inflammatory process and an increase in the structural organization of collagen in the CSAT and CSAT + MSC groups. A study of the genomic integrity of the cells suggested a linear correlation between an increase of injuries and culture time. Thus, MSC transplantation is a good alternative for treatment of Achilles tendon ruptures because it may be conducted without surgery and tendon suture and, therefore, has no risk of adverse effects resulting from the surgical wound or inflammation caused by nonabsorbable sutures. Furthermore, this alternative treatment exhibits a better capacity for wound healing and maintaining the original tendon architecture, depending on the arrangement of the collagen fibers, and has important therapeutic potential.

Individual variation is the key to the development of a vaccine against Staphylococcus aureus: a comparative study between mice lineages.

Bacterial infections occur worldwide and are a major public health problem. Among pathogens, Staphylococcus aureus is the main causative agent of bacterial diseases in the world. This study aimed to evaluate which components of the immune system could act protectively against a S. aureus infection in intradermally immunized mice. C57BL/6 and A/j mice were immunized intradermally with S. aureus inactivated by heat and then challenged with viable strains in an air pouch model. At 6, 12, and 24 h after the challenge, euthanasia was performed, and the cellular profile of the inflammatory infiltrate, cytokines, and the bacterial load were evaluated in the air pouch lavages. Immunized mice demonstrated that the intradermal immunization with S. aureus promoted protection in C57BL/6 mice by reducing the bacterial, which was correlated with increased serum concentration of IgG antibodies (IgG1 and IgG2a) against S. aureus. The increase in IgG2a antibody levels was correlated with a decrease of bacterial load in intradermally immunized C57BL/6 mice, along with production of IL-17A at the inflammation site, as well as IgG1consumption. Similar results were not found in the A/j lineage. In conclusion, a vaccine against S. aureus should focus more on the individual characteristics of the host because it is a determinant factor for the success of the immunization.

Knowledge about transplantation and attitudes toward organ donation: a survey among medical students in northeast Brazil.

During the registration for the second semester of 2002, 779 of the 1001 students from the Medical School, Federal University of Bahia, Brazil, answered an anonymous multiple-choice questionnaire including demographic variables, knowledge about transplantation issues, and willingness to donate organs. Mean age was 21.9 +/- 2.9 years (range: 17 to 51 years); 59.5% were men. Regarding the knowledge of which organs and tissues could be transplanted, 99.1% answered kidneys, 96.1% heart, 88.2% liver, 41.1% lung, 24.0% pancreas, 9% bowel, 98.3% corneas, 89.5% bone marrow, 38.1% heart valves, 47.7% skin, and 18.5% bone and tendons. Regarding the criteria of death, 82.4% answered that it is the lack of all brain activity, 8.2% cardiac arrest, 5.2% irreversible coma, and 4.2% did not know. As to the Brazilian transplantation law, 47.3% did not know, 51% had heard about it, and 1.7% answered that they knew the law in detail. As to the willingness to donate organs, 538 (69.2%) were donors. Of 239 nondonors, 51.1% answered the reason for not donating was the lack of confidence in the heath system, 14.3% had no knowledge of the matter, 17.7% were concerned about organ removal before brain death, and 1.7% for religious reasons. The percentage of those willing to donate organs was greater among spiritualists than among Catholics and Protestants. The results of this study support a greater emphasis on providing information regarding transplantation in medical schools to improve the knowledge of future heath care professionals about transplantation and organ donation issues.

Molecular identification of Paracoccidioides brasiliensis by PCR amplification of ribosomal DNA.

We have amplified and sequenced the 5.8S and 28S ribosomal DNA genes and intergenic regions of Paracoccidioides brasiliensis, strain Pb01. Using primers specifically designed for both ribosomal DNA regions, we were able to discriminate between P. brasiliensis and other human pathogenic fungi by PCR. The use of this molecular marker could be important for paracoccidiodomycosis diagnosis and ecological and molecular epidemiological studies of P. brasiliensis in Latin America.

Differential expression of an hsp70 gene during transition from the mycelial to the infective yeast form of the human pathogenic fungus Paracoccidioides brasiliensis.

We have isolated and characterized cDNA and genomic clones that encode a 70 kDa heat shock protein (Hsp70) from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis. The gene encodes a 649-amino-acid protein showing high identity with other members of the hsp70 gene family. The hsp70 gene is induced during both heat shock of yeast cells at 42 degrees C and the mycelial to yeast transition. A differential expression of this gene can be observed between mycelial and yeast forms, with a much higher level of expression in the yeast. We found two introns of 178 and 72 nucleotides in the P. brasiliensis hsp70 gene. Splicing of these introns is regulated during the heat shock process and possibly during infection. In order to analyse the differential accumulation of unspliced mRNA following cellular differentiation and/or heat shock, reverse transcriptase-polymerase chain reaction (RT-PCR) experiments were carried out. The temperature-induced mycelial to yeast transition results in the transient accumulation of unspliced hsp70 mRNA transcripts. Yeast cells, after adaptation at 36 degrees C, seem to be more proficient at splicing, at least with respect to hsp70 mRNA because, during a severe heat shock (42 degrees C), the unspliced form of this mRNA does not accumulate. The mycelial to yeast differentiation will have the adaptational effect of increasing the resistance of the organism to environmental stress, which may be necessary for parasite survival in the mammalian host.