Advances in separation methods for the use of platelet-rich fibrin in tissue repair: an integrative review.

Plasma preparations originating from the centrifugation of blood samples, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), have proven useful for the treatment of gingival recession due to their rich concentration of cells and cytokines fundamental in the mechanisms of both soft tissue and hard tissue repair. Depending on the preparation method used to generate PRP and PRF, different concentrations of plasma elements and physicochemical characteristics can be obtained. This study sought to perform an integrative literature review to compile the available data on different protocols for generating plasma preparations and their indications, benefits, and results. A descriptive research method was adopted for assessing the literature on processes for obtaining PRF, and articles indexed in the MEDLINE database were searched. The literature review showed that changes in the PRF protocols for obtaining blood concentrates have led to better isolation of cells and growth factors and more promising results in tissue repair. The evolution in protocols has resulted in various forms of PRF with different components: (1) a membrane that aggregates platelets and leukocytes (L-PRF); (2) a PRF rich in growth factors and cytokines, known as advanced PRF (A-PRF); (3) a liquid phase called injectable PRF (I-PRF) that shows greater cell accumulation than L-PRF; (4) A-PRF plus (A-PDF+), which improved the release of growth factors for a period of 10 days; and (5) concentrated PRF (C-PRF) obtained by progressive pipetting, which has the greatest cell accumulation among all of the types of platelet aggregates. Subsequently, the observation that the speed of centrifugation influenced the acquisition of specific cells resulted in the development of the low-speed centrifugation concept. Then, it was determined that reduction of the relative centrifugation forces significantly increased the number of platelets, leukocytes, and growth factors. Recently, evaluation of the centrifugation angle revealed greater entrapment of large cells, such as red blood cells, when centrifugation was changed from a fixed to a horizontal angle. Tissue bioengineering studies are allowing for significant advances in the process of obtaining blood components and enabling their use for tissue repair with greater predictability and less morbidity.

Primer registro de Saguinus fuscicollis melanoleucus (Miranda Ribeiro, 1912) en la Amazonía peruana / First record of Saguinus fuscicollis melanoleucus (Miranda Ribeiro, 1912) in the Peruvian Amazon

En el presente trabajo reportamos la presencia de Saguinus fuscicollis melanoleucus en la AmazoníaPeruana. Esta subespecie fue registrada, durante los censos de fauna silvestre y también de manera ocasional, en las cuencas altas del río Breu y de la quebrada Beu cerca de la frontera con Brasil en el distrito de Yurúa, departamento de Ucayali. En la Amazonía peruana, los hábitats de Saguinus fuscicollis melanoleucus comprenden el bosque primario y el bosque mixto con Guaduasp. en buen estado de conservación. Esta zona es habitada por las comunidades indígenas Amahuaca, en el lado peruano y Kashinawa, en el lado brasileño.

The fist record of Saguinus fuscicollis melanoleucus to the Peruvian Amazon is reported. This subspecies was registered by wildlife census and by an occasional record from the headwaters of the Breu and Beu rivers near to the limit with Brazil in the district of Yurua, department of Ucayali. The habitat of Saguinus fuscicollis melanoleucus in Peru includes primary forest and forests with Guadua sp. This place is inhabited by Amahuaca (Peruvian side) and Kashinawa (Brazilian side) indigenous communities.

Cell surface phenotype and human T lymphotropic virus type 1 antigen expression in 12 T cell lines derived from peripheral blood and cerebrospinal fluid of West Indian, Guyanese and African patients with tropical spastic paraparesis

Twelve long term cell lines were established from peripheral blood mononuclear cells (PBMC) or cerebrospinal fluid cells of patients with human T lymphotropic virus type I (HTLV-I) seropositive tropical spastic paraparesis (TSP) originating from the French West Indies, French Guyana or the Central African Republic. Most of these long term interlukin-2-dependent cell lines exhibited a pattern characteristic of CD4+ -activated T cells with high expression of CD2, CD3 and CD4 antigens, associated with a strong density of TAC and DR molecules. Nevertheless, in five cases CD8 expression was present at a significant level. HTLV-I antigens were expressed in a few cells after short-term culture and after 4 months the majority of the cells were HTLV-I positive, as demonstrated by indirect immunofluorescence (IF) using polyclonal or monoclonal anti-p19 and anti-p24 antibodies. Low and variable levels of reverse transcriptase activity were detected in supernatant fluids of these cell lines only after 4 months of culture, when at least 50 percent of the cells exhibited HTLV-I antigens by IF. However numerous type C HTLV-I-like viral particles were detected, mostly in the extracellular spaces, with rare budding particles. Similar findings were found in three T cell lines derived from West Indian and African patients with adult T-cell leukaemia/lymphoma (ATLL). Differences in high M-r polypeptides were detected by Western blot in cell lysates when comparing TSP-or ATLL-derived T cell lines. Thus a signal of 62K was easily detectable in all the TSP lines, but not in the ATLL lines. In all cell lines bands corresponding to p53, p24 and p19 viral core polypeptides were present, as was the env gene-coded protein p46. (AU)