Abstract The importance of monitoring in vivo interaction that occurs between cells /bio/tissue recipient in the understanding of tissue regeneration processes becomes ever greater. This study aims to monitor and evaluate the influence of scaffold implants of poly (L-co-D, L lactic acid) - PLDLA synthesized in the laboratory, previously cultured with primary osteoblastic cells heterologously stained with the fluorescent vital dye, PKH26, on the tissue regeneration process in 8 mm central critical defects of the Wistar rat calvaria. The results obtained by MTT assay and monitoring of cells stained with PKH26 dye over 14 days of culture showed that the dye was cytocompatible with osteoblastic cells and did not exert a negative influence on the growth of unstained cells. In the in vivo study, macroscopic observations made during deployment times corroborate the results in vitro, as no apparent signs of toxicity were observed in the implanted bone defect area. The use of mobile monitoring with the dye, PKH26 in vivo is an effective strategy for the understanding of cell behaviour in the presence of PLDLA polymer.

In bone tissue engineering, cell-scaffold constructs are used to stimulate complete, functional tissue replacement that does not occur naturally in critical-size defects. In this report, we describe the application potential of poly (L-co-D,L lactic acid)-PLDLA 70/30, synthesized in house as constructs loaded with osteoblast-like cells on bone tissue engineering. In vitro biological results show that the porogen leached PLDLA scaffolds are cytocompatible with osteoblast cells, able to stimulate significant cells growth during the first 14 days of culture, during which the morphology and cell behavior of osteoblasts cultured on the scaffolds were monitored by scanning electron microscopy (SEM). In vivo, PLDLA constructs were implanted in 5 mm bilateral critical-size defects created in rat-calvariae and then evaluated histologically 8 and 12 weeks after implantation. The histological results showed that PLDLA constructs supported the growth of new tissue, with a degradation rate close to that of native bone formation and decrease of inflammatory response over time of implantation. These data provide evidences that the synthesized PLDLA polymer has application potential as construct for bone tissue engineering.

The physiological repair of osteochondral lesions requires the development of a scaffold that is compatible with the structure of the damaged tissue, cartilage and bone. The aim of this study was to evaluate the biological performance of a PLDLA/PCL-T (90/10) scaffold for repairing osteochondral defects in rabbits. Polymeric scaffolds containing saccharose (75% w/v) were obtained by solvent casting and then implanted in the medial knee condyles of 12 New Zealand rabbits after osteochondral damage with a trephine metallic drill (diameter: 3.3 mm) in both medial femoral condyles. Each rabbit received the same treatment, i.e., the polymeric scaffold was implanted on the right side while no material was implanted on the left side (control). Four and 12 weeks later histological examination revealed bone neoformation in the implant group, with the presence of hyaline cartilage and mesenchymal tissue. In contrast, the control group showed bone neoformation with necrosis, exacerbated superficial fibrosis, inflammation and cracks in the neoformed tissue. These findings indicate that the PLDLA/PCL-T scaffold was biocompatible and protected the condyles by stabilizing the lesion and allowing subchondral bone tissue and hyaline cartilage formation.

A síndrome do anticorpo antifosfolípide (SAF), mais comum em mulheres, manifesta-se clinicamente como trombose e/ou abortamentos de repetição. Anemia hemolítica autoimune e manifestações neurológicas, cardíacas e cutâneas são comuns. Relata-se o caso de um paciente do gênero masculino cuja manifestação inicial da doença foi gangrena em pavilhão auricular, e o diagnóstico de SAF se deu por meio de biópsia de pele do membro inferior, que mostrava vasculopatia trombótica, sem evidência de vasculite. Esse resultado é um dos dois critérios maiores que, associados a um critério menor, fecham o diagnóstico dessa doença. Discutem-se neste caso os possíveis diagnósticos diferenciais e como eles se diferenciam da doença em foco, além da importância que a biópsia teve no diagnóstico de SAF nesse indivíduo.

Antiphospholipid syndrome (APS), more common in females, manifests clinically as thrombosis and/or recurrent fetal loss. Hemolytic autoimmune anemia and neurological, cardiac and cutaneous manifestations are common. This is the case report of a male patient whose first manifestation of the disease was gangrene of the auricle. The diagnosis of APS was established by biopsy of the lower limb skin, which showed thrombotic vasculopathy with no evidence of vasculitis. This is one of the two major criteria, which, along with a minor criterion, establishes the diagnosis of APS. Possible differential diagnoses are discussed. The importance of the biopsy in the APS diagnosis of this male patient is emphasized.