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Donor Tissue (donor + tissue)

Distribution by Scientific Domains

Medical Sciences	80%
Life Sciences	20%

Selected Abstracts

Back to Basics: The Subcutaneous Island Pedicle Flap

DERMATOLOGIC SURGERY, Issue 12p2 2004
Janie M. Leonhardt MD
Background. Optimal aesthetic reconstruction of cutaneous defects following excisional surgery is largely dependent on the availability of regional donor tissue that shares a likeness of the original tissue in color, texture, sebaceous quality, and thickness. The island pedicle flap is a useful tool in facial reconstruction because it minimizes regional anatomic distortion and optimizes tissue match. Objective. The objective was to review four locations where the island pedicle flap is a well-suited closure tool. Methods. We review flap planning and specific modifications of the island pedicle flap at four sites of closure, reinforcing its role as an important tool in facial reconstruction. Results. Through careful planning and implementation, the island pedicle flap may be used on the nasal tip, the nasal ala, the upper cheek, and the upper lip for closures with much success. Conclusion. The island pedicle flap remains an important tool in the armamentarium for surgeons in the repair of facial defects. [source]

A hVIPR transgene as a novel tool for the analysis of circadian function in the mouse suprachiasmatic nucleus

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2003
V. M. King
Abstract A mouse bearing a novel transgene encoding the human VPAC2 receptor (hVIPR; Shen et al. (2000) PNAS, 97, 11575,11580) was used to investigate circadian function in the hypothalamic suprachiasmatic nuclei (SCN). Neurons expressing hVPAC2R, detected by a beta-galactosidase (,-GAL) tag, have a distinct distribution within the SCN, closely matching that of neurophysin (NP) neurons and extending into the region of peptide histidine isoleucine (PHI) cells. In common with NP and PHI cells, neurons expressing hVPAC2R are circadian in nature, as revealed by synchronous rhythmic expression of mPERIOD (mPER) proteins. A population of SCN cells not expressing PHI, NP or hVPAC2R exhibited circadian PER expression antiphasic with the rest of the SCN. Nocturnal light exposure induced mPER1 in the ventral SCN and mPER2 widely across the nucleus. Induction of nuclear mPER2 in hVPAC2R cells confirmed their photic responsiveness. Having established their circadian properties, we tested the utility of SCN neurons expressing the hVIPR transgene as functionally and anatomically explicit markers for SCN tissue grafts. Prenatal SCN tissue from hVIPR transgenic pups survived transplantation into adult CD1 mice, and expressed ,-GAL, PER and PHI. Over a series of studies, hVIPR transgenic SCN grafts restored circadian activity rhythms to 17 of 72 arrhythmic SCN lesioned recipients (23.6%). By using heterozygous hVIPR transgenic grafts on a heterozygous Clock mutant background we confirmed that restored activity rhythms were conferred by the donor tissue. We conclude that the hVIPR transgene is a powerful and flexible tool for examination of circadian function in the mouse SCN. [source]

Impaired liver regeneration and increased oval cell numbers following T cell,mediated hepatitis,

HEPATOLOGY, Issue 1 2007
Ian N. Hines
The regeneration of liver tissue following transplantation is often complicated by inflammation and tissue damage induced by a number of factors, including ischemia and reperfusion injury and immune reactions to the donor tissue. The purpose of the current study is to characterize the effects of T cell,mediated hepatitis induced by concanavalin A (ConA) on the regenerative response in vivo. Liver regeneration following a partial (70%) hepatectomy (pHx) was associated with elevations in serum enzymes and the induction of key cell cycle proteins (cyclin D, cyclin E, and Stat3) and hepatocyte proliferation. The induction of T cell,mediated hepatitis 4 days before pHx increased serum enzymes 48 hours after pHx, reduced early cyclin D expression and Stat3 activation, and suppressed hepatocyte proliferation. This inhibition of proliferation was also associated with increased expression of p21, the activation of Smad2, the induction of transforming growth factor beta and interferon gamma expression, and reduced hepatic interleukin 6 production. Moreover, the ConA pretreatment increased the numbers of separate oval cell-like CD117+ cells and hematopoietic-like Sca-1+ cell populations 48 hours following pHx. The depletion of natural killer (NK) cells, an important component of the innate immune response, did not affect liver injury or ConA-induced impairment of hepatocyte proliferation but did increase the numbers of both CD117-positive and Sca-1,positive cell populations. Finally, splenocytes isolated from ConA-pretreated mice exerted cytotoxicity toward autologous bone marrow cells in an NK cell,dependent manner. Conclusion: T cell,mediated hepatitis alters early cytokine responses, reduces hepatocellular regeneration, and induces NK cell,sensitive oval cell and hematopoietic-like cell expansion following pHx. (HEPATOLOGY 2007;46:229,241.) [source]

Acellular dermal allograft for vestibuloplasty,an alternative to autogenous soft tissue grafts in preprosthetic surgical procedures: A clinical report

JOURNAL OF PROSTHODONTICS, Issue 2 2003
Monish Bhola DDS
Various vestibular extension procedures have been described in the literature over the past 6 decades, including the use of free gingival grafts. An acellular dermal allograft has been used as a substitute for autogenous soft tissue grafts in root coverage procedures. This clinical report describes the use of such an allograft as a substitute for palatal donor tissue in the vestibular extension of an edentulous maxillary arch with multiple frenum attachments before fabrication of a complete denture. In this patient, healing was uneventful, and 6-month clinical observations demonstrated an apical positioning of the mucogingival junction with an increase in vestibular depth, and the absence of multiple frenae. The acellular dermal allograft appears to be a useful substitute for autogenous palatal grafts in preprosthetic surgery. This approach has many advantages over the free gingival graft, including no donor site morbidity, unlimited availability, and better color match. [source]

Cartilage tissue engineering using resorbable scaffolds

JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2007
Nicole Rotter
Abstract Cartilage tissue engineering holds considerable promise for orthopaedic and reconstructive head and neck surgery. With an increasingly ageing population, the number of patients affected by arthritis and recurrent joint pain is constantly growing, along with the associated socio-economic costs. In head and neck surgery reconstructive procedures gain increasing importance in multimodal tumour therapies. These procedures require the harvesting of large amounts of donor tissue, which causes significant donor site morbidity. Therefore, in vitro -engineered cartilage may provide for a cost-effective and clinically valuable medical need. This article presents an overview of the clinical background as well as considerations for engineered cartilage in the head and neck, and provides examples of cartilage tissue engineering based on various scaffolds. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Myogenic precursor cells in craniofacial muscles

ORAL DISEASES, Issue 2 2007
LK McLoon
Craniofacial skeletal muscles (CskM), including the masticatory (MM), extraocular (EOM) and laryngeal muscles (LM), have a number of properties that set them apart from the majority of skeletal muscles (SkM). They have embryological origins that are distinct from musculature elsewhere in the body, they express a number of immature myosin heavy chain isoforms and maintain increased and distinct expression of a number of myogenic growth factors and their receptors from other adult SkMs. Furthermore, it has recently been demonstrated that unlike limb SkM, normal adult EOM and LM retain a population of activated satellite cells, the regenerative cell in adult SkM. In order to maintain this proliferative pool throughout life, CSkM may contain more satellite cells and/or more multipotent precursor cells that may be more resistant to apoptosis than those found in limb muscle. A further exciting question is whether this potentially more active muscle precursor cell population could be utilized not only for SkM repair, but be harnessed for repair or reconstruction of other tissues, such as nervous tissue or bone. This is a highly attractive speculation as the innate regenerative capacity of craniofacial muscles would ensure the donor tissue would not have compromised future function. [source]

Grafting of the posterior cornea.

ACTA OPHTHALMOLOGICA, Issue 5 2000
Description of a new technique with 12-month clinical results
ABSTRACT. Purpose: To describe the technique of grafting only the posterior cornea and to report 12-month clinical results. Method: A two-layer technique with an anterior recipient flap created by a microkeratome and a posterior penetrating donor graft allows for a watertight wound closure and at the same time a peroperative correction of astigmatism. Four eyes (3 patients) were followed for 12 months. Results: The surgical technique could be completed in all cases without complications. The postoperative course was uneventful. The intrastromal absorbable sutures disappeared spontaneously and completely. Graft thickness showed the expected 6-month minimum while recipient flap thickness remained constant. After 1 year endothelial cell densities were 1200,2300 cells/mm2. Confocal microscopy showed activated keratocytes in the flap and quiescent keratocytes in the donor tissue by one year. The anterior chamber depth was normal in all cases. The optical quality of the cornea was studied by automatic keratometry and keratoscopy (TMS). The obtained optical properties were not optimal. Conclusions: The developed novel technique gives a better wound closure and a complication free postoperative course. It may allow for better control of postoperative astigmatism. In order to disseminate the use of the technique, eyebanks should supply posterior corneas to the surgeon. [source]

Dissection and cotransplantation of large pieces of RPE and neural retina; effect of protease K on the development

ACTA OPHTHALMOLOGICA, Issue 1 2000
Rajesh Kumar Sharma
ABSTRACT. Purpose: This study attempts to cotransplant large pieces of the RPE and neural retina in the subretinal space of rabbits by using protease K for dissection of the donor tissue, and to investigate the effect of dissection technique on the development of the grafts. Methods: Eyes from 15-day-old pigmented rabbit embryos were partly digested by protease K to assist dissection of sclera and the choroid from RPE and neural retina. Large pieces of RPE and the neural retina thus obtained were cotransplanted into the eyes of adult albino rabbits who were allowed to survive for up to 63 days. The transplants were examined under light microscope. Results: It was possible to transplant large sheets of RPE and neural retina together. Both the RPE and the neural retina survived after cotransplantation. Retinal pigment epithelium survived in layers, but at places formed clusters. In cotransplants neural retina formed rosettes, developed gliosis, and photoreceptors failed to develop outer segments, possibly due to the action of protease K. Conclusion: Proteases seem to be injurious for the development of the neural retina. [source]

Reviewing the vascular supply of the anterior abdominal wall: Redefining anatomy for increasingly refined surgery

CLINICAL ANATOMY, Issue 2 2008
W.M. Rozen
Abstract The abdominal wall integument is becoming the standard donor tissue for postmastectomy breast reconstruction, with its vascular supply of key importance to the reconstructive surgeon. Refinements in tissue transfer, from pedicled to free flaps and musculocutaneous to perforator flaps, have required increasing understanding of finer levels of this vascular anatomy. The widespread utilization of the deep inferior epigastric artery (DIEA) perforator flap, particularly for breast reconstruction, has rekindled clinical interest in further levels of anatomical detail, in particular the location and course of the musculocutaneous perforators of the DIEA. Advances in operative techniques, and anatomical and imaging technologies, have facilitated an increase in this understanding. The current review comprises an appraisal of both the anatomical and clinical literature, with a view to highlighting the key anatomical features of the abdominal wall vasculature as related to reconstructive flaps. Clin. Anat. 21:89,98, 2008. © 2008 Wiley-Liss, Inc. [source]

Musculoskeletal tissue banking in Western Australia: review of the first ten years

ANZ JOURNAL OF SURGERY, Issue 8 2005
Joyleen M. Winter
Background: Musculoskeletal tissue allotransplantation has been used as a standard approach for reconstructive surgery. The present study has reviewed the banking of musculoskeletal tissue at the Perth Bone and Tissue Bank (PBTB) and provided evidence of quality assurance on musculoskeletal tissue allotransplantation. Methods: All donor tissues were processed in accordance with the Therapeutic Goods Administration's relevant codes of good manufacturing practices. Microbiological monitoring at each step of manufacture and postoperative surveying of the musculoskeletal allotransplantations were both conducted. The possible contribution of contaminants in allografts to postoperative infections was also assessed. Results: Of the 5276 donors obtained over the last 10 years, 1672 were rejected, giving an overall donor rejection rate of 32%. Milled femoral heads were the most frequently implanted allografts, followed by whole femoral heads. In the postoperative survey an infection rate of 4.9% was found (113/2321 recipients). The infectious agents were identified in 65 cases but for 60 of these there were no correlations with the positive culture test results for the allografts. The organism most commonly identified in postoperative infections was Staphylococcus species. Conclusions: The present study shows evidence that musculoskeletal tissue allotransplantation is a safe procedure when accompanied by high standards of quality assurance. [source]