Search results for " transplantation."

Intraepidermal formation of Merkel cells in xenografts of human fetal skin.

1990

An experimental transplantation model using human fetal skin was applied to approach the question of the embryologic origin of human Merkel cells. Palmar and plantar skin from five fetuses, between 8 and 11 weeks of estimated gestational age (EGA), was xenografted to subcutaneous beds of nude mice. After 4 or 8 weeks of growth, biopsies were taken from these xenografts and examined for the presence of Merkel cells, using immunocytochemistry with antibodies specific for simple epithelial-type cytokeratins and neuron-specific enolase (NSE) as well as using electron microscopy. Skin from the same fetuses at the time of transplantation was screened in the same way. In all fetuses, no (or very s…

Isolation, cultivation and characterization of human somatic stem cells from adult skin, adipose tissue and bone marrow

2008

Isolation, cultivation and characterization of human somatic stem cells from adult skin, adipose tissue and bone marrow

Potential lack of "standardized" processing techniques for production of allogeneic and xenogeneic bone blocks for application in humans.

2013

In the present study, the structure of two allogeneic and three xenogeneic bone blocks, which are used in dental and orthopedic surgery, were histologically analyzed. The ultimate goal was to assess whether the components postulated by the manufacturer can be identified after applying conventional histological and histochemical staining techniques. Three samples of each material, i.e. allogeneic material-1 and -2 as well as xenogeneic material-1, -2 and -3, were obtained commercially. After decalcification and standardized embedding processes, conventional histological staining was performed in order to detect inorganic matrix, cellular or organic matrix components. Allogeneic material-1 sh…

Application of mesenchymal stem cells in bone regenerative procedures in oral implantology. A literature review

2013

Objective: The aim of this work was to review de literature about the role of mesenchymal stem cells in bone regenerative procedures in oral implantology, specifically, in the time require to promote bone regeneration. Study Design: A bibliographic search was carried out in PUBMED with a combination of different key words. Animal and human studies that assessed histomorphometrically the influence of mesenchymal stem cells on bone regeneration procedures in oral implantology surgeries were examined. Reults: - Alveolar regeneration: Different controlled histomorphometric animal studies showed that bone regeneration is faster using stem cells seeded in scaffolds than using scaffolds or platele…

Irradiation Delays Tissue Growth but Enhances Osteogenic Differentiation in Vascularized Constructs.

2018

Background Regenerative medicine is still deficient in the reconstruction after cancer due to impaired vascularization after radiotherapy and due to the need to substitute larger defects after tumor excision. Aiming at introducing regenerative medicine for reconstruction after cancer, we tested an axially vascularized bone construct in an experimental setting that mimics the clinical situation after tumor resection and adjuvant radiotherapy. Methods Twenty bone constructs were axially vascularized using microsurgically created arteriovenous loops and were implanted subcutaneously in Lewis rats. After 2 weeks, the animals were randomly allocated either to receive a clinically relevant singl…

Human bone marrow mesenchymal stem cells display anti-cancer activity in SCID mice bearing disseminated non-Hodgkin's lymphoma xenografts.

2010

Background Although multimodality treatment can induce high rate of remission in many subtypes of non-Hodgkin's lymphoma (NHL), significant proportions of patients relapse with incurable disease. The effect of human bone marrow (BM) mesenchymal stem cells (MSC) on tumor cell growth is controversial, and no specific information is available on the effect of BM-MSC on NHL. Methodology/Principal Findings The effect of BM-MSC was analyzed in two in vivo models of disseminated non-Hodgkin's lymphomas with an indolent (EBV− Burkitt-type BJAB, median survival = 46 days) and an aggressive (EBV+ B lymphoblastoid SKW6.4, median survival = 27 days) behavior in nude-SCID mice. Intra-peritoneal (i.p.) i…

Could tubular interstitium be a source of adult epithelial stem cells?

2006

Cardiac tissue engineering: a reflection after a decade of hurry

2014

The heart is a perfect machine whose mass is mainly composed of cardiomyocytes, but also fibroblasts, endothelial, smooth muscle, nervous, and immune cells are represented. One thousand million cardiomyocytes are estimated to be lost after myocardial infarction, their loss being responsible for the impairment in heart contractile function (Laflamme and Murry, 2005). The potential success of cardiac cell therapy relies almost completely on the ability of the implanted cells to differentiate toward mature cardiomyocytes. These cells must be able to reinforce the pumping activity of the injured heart in the absence of life-threatening arrhythmias due to electrophysiological incompatibility. Th…

Unexpected postmortem diagnosis of Acanthamoeba meningoencephalitis following allogeneic peripheral blood stem cell transplantation.

2008

Meningoencephalitis caused by pathogenic free-living amebas is usually fatal. Only a few cases of Acanthamoeba meningoencephalitis, diagnosed at autopsy, have been reported following hematopoietic stem cell transplantation. We here report a case of Acanthamoeba meningoencephalitis following allogeneic peripheral blood stem cell transplantation with rapidly evolving neurologic symptoms that remained unexplained. Magnetic resonance imaging failed to show brain lesions and cerebrospinal fluid was negative for microbiological cultures. Definite diagnosis was an unexpected autopsy finding. As overall and teaching hospital autopsy rates are declining worldwide, we must emphasize the need of autop…

Immunomodulation in vascularized composite allotransplantation: What is the role for adipose-derived stem cells?

2019

Hand and face transplants are becoming increasingly common, recording progressively more penile, uterus, abdominal wall, and allotransplantation cases reported worldwide. Despite current protocols allow long-term survival of the allografts, the ultimate goal of donor-specific tolerance has not been achieved yet. In fact, the harmful adverse effects related to the lifelong administration of immunosuppressive agents are the main drawbacks for vascularized composite allotransplantations. Research is very active in investigating alternative methods to induce greater tolerance while minimizing toxicity. Adipose-derived stem cells (ASCs) represent promising cell therapies for immunomodulation in …