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1.
J Plast Reconstr Aesthet Surg ; 75(9): 3234-3241, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35906161

RESUMO

Although the primary aim of pollicization is to augment function, aesthetic improvement is an important secondary aim. Satisfaction with hand appearance in children with index pollicization for thumb hypoplasia was evaluated in 18 patients at an average of 7.5 years after surgery. Patients and their parents rated the appearance of their operated hand using a 10-point visual analogue scale (VAS). Four independent surgeons and 16 non-surgeon observers also rated the hands after reviewing standardized photographs of each child. The median patient-reported and parent-reported scores were 9 for both groups (IQR: 7-10) with a trend for children 12 years and older, to report lower satisfaction with appearance. The non-surgeon group assessments varied more for a given hand than the surgeons' assessments, though when scores were averaged within these groups for each hand, there was a high degree of correlation between the two groups. Surprisingly, the patient's own assessment showed a trend towards negative correlation when compared with the average rating of the non-surgeon assessors, suggesting that patients' own assessment of their hand's appearance is more affected by subjective factors than the objective physical outcome.


Assuntos
Satisfação Pessoal , Polegar , Criança , Dedos/cirurgia , Deformidades da Mão , Força da Mão , Humanos , Polegar/anormalidades
2.
J Tissue Eng Regen Med ; 12(1): e408-e421, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28477583

RESUMO

Vascularization is a major hurdle for growing three-dimensional tissue engineered constructs. This study investigated the mechanisms involved in hypoxic preconditioning of primary rat myoblasts in vitro and their influence on local angiogenesis postimplantation. Primary rat myoblast cultures were exposed to 90 min hypoxia at <1% oxygen followed by normoxia for 24 h. Real time (RT) polymerase chain reaction evaluation indicated that 90 min hypoxia resulted in significant downregulation of miR-1 and miR-206 (p < 0.05) and angiopoietin-1 (p < 0.05) with upregulation of vascular endothelial growth factor-A (VEGF-A; p < 0.05). The miR-1 and angiopoietin-1 responses remained significantly downregulated after a 24 h rest phase. In addition, direct inhibition of miR-206 in L6 myoblasts caused a significant increase in VEGF-A expression (p < 0.05), further establishing that changes in VEGF-A expression are influenced by miR-206. Of the myogenic genes examined, MyoD was significantly upregulated, only after 24 h rest (p < 0.05). Preconditioned or control myoblasts were implanted with Matrigel™ into isolated bilateral tissue engineering chambers incorporating a flow-through epigastric vascular pedicle in severe combined immunodeficiency mice and the chamber tissue harvested 14 days later. Chambers implanted with preconditioned myoblasts had a significantly increased percentage volume of blood vessels (p = 0.0325) compared with chambers implanted with control myoblasts. Hypoxic preconditioned myoblasts promote vascularization of constructs via VEGF upregulation and downregulation of angiopoietin-1, miR-1 and miR-206. The relatively simple strategy of hypoxic preconditioning of implanted cells - including non-stem cell types - has broad, future applications in tissue engineering of skeletal muscle and other tissues, as a technique to significantly increase implant site angiogenesis.


Assuntos
Regulação para Baixo , Implantes Experimentais , MicroRNAs/genética , Mioblastos/patologia , Neovascularização Fisiológica , Engenharia Tecidual/instrumentação , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Biomarcadores/metabolismo , Hipóxia Celular/genética , Células Cultivadas , Desmina/metabolismo , Regulação para Baixo/genética , Masculino , Camundongos SCID , MicroRNAs/metabolismo , Desenvolvimento Muscular/genética , Mioblastos/metabolismo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Alicerces Teciduais/química , Regulação para Cima/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
3.
Br J Dermatol ; 178(2): 473-481, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28986976

RESUMO

BACKGROUND: An important limitation in vascular malformation research is the heterogeneity in outcome measures used for the evaluation of treatment outcome. OBJECTIVES: To reach international consensus on a core outcome set (COS) for clinical research on peripheral vascular malformations: lymphatic (LM), venous (VM) and arteriovenous malformations (AVM). In this consensus study, we determined what domains should constitute the COS. METHODS: Thirty-six possibly relevant outcome domains were proposed to an international group of physicians, patients and the parents of patients. In a three-round e-Delphi process using online surveys, participants repeatedly rated the importance of these domains on a five-point Likert scale. Participants could also propose other relevant domains. This process was performed for LM, VM and AVM separately. Consensus was predefined as 80% agreement on the importance of a domain among both the physician group and the patient/parent group. Outcomes were then re-evaluated in an online consensus meeting. RESULTS: 167 physicians and 134 patients and parents of patients with LM (n = 50), VM (n = 71) and AVM (n = 29) participated in the study. After three rounds and a consensus meeting, consensus was reached for all three types of vascular malformations on the core domains of radiological assessment, physician-reported location-specific signs, patient-reported severity of symptoms, pain, quality of life, satisfaction and adverse events. Vascular malformation type-specific signs and symptoms were included for LM, VM and AVM, separately. CONCLUSIONS: Our recommendation is that therapeutic-efficacy studies on peripheral vascular malformations should measure at least these core outcome domains.


Assuntos
Malformações Vasculares/terapia , Malformações Arteriovenosas/terapia , Consenso , Técnica Delphi , Humanos , Sistema Linfático/anormalidades , Resultado do Tratamento
5.
Lymphology ; 50(1): 16-26, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30231304

RESUMO

Lymphatic malformations are a developmental anomaly arising from a somatic mutation in the lymphatic endothelial cells. This study investigated parental experiences associated with prenatal diagnosis of LM. Parents of 5 children diagnosed prenatally with LM were recruited from the Vascular Anomalies Clinic at the Royal Childrens Hospital, Melbourne. Ten in-depth semistructured interviews were conducted with each parent separately to explore their experiences and views at the time of diagnosis and immediately after childbirth. Transcribed interviews were coded and thematically analyzed. Parents experienced prenatal diagnosis of LM as an unexpected and traumatic event. The lack of adequate information and clear care pathway created confusion and added to the difficulty of understanding the impact of LM on the unborn child and what to expect after the child was born. Parents used the internet as the primary source of additional information; however, some parents found that information distressing. Differences between mothers and fathers were noted in terms of roles that each parent played and their emotional responses during pregnancy and the prenatal diagnosis. Closer connection between obstetric centers and specialized treatment clinics are suggested to facilitate better understanding of the LM impact on the unborn child and available treatment options after birth.

6.
Br J Dermatol ; 165(6): 1223-35, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21895624

RESUMO

BACKGROUND: Inducible nitric oxide synthase (nitric oxide synthase 2, NOS 2) inhibition significantly suppresses chronically ischaemic skin flap survival, possibly because of reduced angiogenesis. OBJECTIVES: To investigate the effect of genetic NOS 2 inhibition on cutaneous wound angiogenesis in two in vivo murine models. The impact of NOS 2 manipulation on vascular endothelial growth factor (VEGF)-A stimulated and fibroblast growth factor (FGF)-2 stimulated angiogenesis was also investigated in the Matrigel(®) plug assay. METHODS: (i) Matrigel plugs/incisional wounds: two groups of NOS 2-/- mice and two groups of wild-type (WT) mice had bilateral Matrigel plugs containing 500 ng mL(-1) VEGF-A or 1000 ng mL(-1) FGF-2 injected subcutaneously in the abdomen. A 2·5 cm long dorsal incisional skin wound was created and sutured closed in the same animals. Wounds and plugs were explored at 7 or 12 days. (ii) Excisional wounds: dorsal 0·5 × 1·0 cm excisional skin wounds were created in four groups (two NOS 2-/- and two WT) and explored at 7 or 14 days. Wounds and Matrigel plugs were examined histologically and morphometrically for determination of percentage vascular volume (PVV). RESULTS: The PVV in NOS 2-/- incisional wounds and excisional wounds was significantly less than in WT wounds (P = 0·05 and P < 0·001, respectively). The PVV was significantly less in VEGF-A stimulated Matrigel plugs compared with FGF-2 stimulated plugs in NOS 2-/- mice (P < 0·01), but not in WT mice. CONCLUSIONS: NOS 2 is significantly involved in angiogenic signalling in healing skin wounds, particularly within the first 7 days. However, Matrigel plug vascularization suggests that the role of NOS 2 in angiogenesis is related to VEGF-A but not FGF-2 stimulated angiogenesis.


Assuntos
Fator 2 de Crescimento de Fibroblastos/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Pele/lesões , Cicatrização/fisiologia , Animais , Colágeno/farmacologia , Combinação de Medicamentos , Isquemia/fisiopatologia , Laminina/farmacologia , Camundongos , Óxido Nítrico Sintase Tipo II/fisiologia , Proteoglicanas/farmacologia , Pele/irrigação sanguínea , Retalhos Cirúrgicos/irrigação sanguínea , Retalhos Cirúrgicos/patologia , Fator A de Crescimento do Endotélio Vascular/metabolismo
7.
Cells Tissues Organs ; 191(5): 382-93, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20090306

RESUMO

Intraportal islet transplantation has shown initial promise for the treatment of type 1 diabetes. However, the portal vein site is associated with complications such as thrombosis and hepatic steatosis, leading to transplant failure. The aims of this study were to (1) test the feasibility of an alternative islet transplantation method that utilises a FDA-approved gelatin sponge as a novel islet carrier and (2) assess if exogenous addition of nerve growth factor (NGF) has any additional beneficial effects on graft performance in diabetic mice. Mice were rendered diabetic by a single intraperitoneal injection of streptozotocin. Five hundred syngeneic islets were seeded onto a Gelitaspon((R)) disc in the presence or absence of NGF, and placed into a silicone chamber surrounding the femoral neurovascular pedicle. Islet function was assessed by weekly monitoring of blood glucose levels and an intraperitoneal glucose tolerance test performed at the end of the study. Chambers were harvested for further histological analysis. Four of five mice transplanted with islets seeded onto Gelitaspon with NGF showed a significant reduction in blood glucose levels by 4 weeks after transplantation, and demonstrated a response similar to non-diabetic mice when tested with an intraperitoneal glucose tolerance test. Chamber tissue from this group contained islets with insulin-producing beta cells adjacent to the vascular pedicle. Islets seeded onto Gelitaspon with NGF and sited on femoral vessels using a tissue-engineering chamber offer an alternative method for islet transplantation in diabetic mice. This may have potential as a method for clinical islet transplantation.


Assuntos
Diabetes Mellitus Experimental/cirurgia , Hiperglicemia/tratamento farmacológico , Transplante das Ilhotas Pancreáticas/métodos , Fator de Crescimento Neural/uso terapêutico , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Teste de Tolerância a Glucose , Camundongos
9.
Int J Obes (Lond) ; 32(2): 239-48, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17684510

RESUMO

OBJECTIVE: To investigate the potential of inflammation to induce new adipose tissue formation in the in vivo environment. METHODS AND RESULTS: Using an established model of in vivo adipogenesis, a silicone chamber containing a Matrigel and fibroblast growth factor 2 (1 microg/ml) matrix was implanted into each groin of an adult male C57Bl6 mouse and vascularized with the inferior epigastric vessels. Sterile inflammation was induced in one of the two chambers by suspending Zymosan-A (ZA) (200-0.02 microg/ml) in the matrix at implantation. Adipose tissue formation was assessed at 6, 8, 12 and 24 weeks. ZA induced significant adipogenesis in an inverse dose-dependent manner (P<0.001). At 6 weeks adipose tissue formation was greatest with the lowest concentrations of ZA and least with the highest. Adipogenesis occurred both locally in the chamber containing ZA and in the ZA-free chamber in the contralateral groin of the same animal. ZA induced a systemic inflammatory response characterized by elevated serum tumour necrosis factor-alpha levels at early time points. Aminoguanidine (40 microg/ml) inhibited the adipogenic response to ZA-induced inflammation. Adipose tissue formed in response to ZA remained stable for 24 weeks, even when exposed to the normal tissue environment. CONCLUSIONS: These results demonstrate that inflammation can drive neo-adipogenesis in vivo. This suggests the existence of a positive feedback mechanism in obesity, whereby the state of chronic, low-grade inflammation, characteristic of the condition, may promote further adipogenesis. The mobilization and recruitment of a circulating population of adipose precursor cells is likely to be implicated in this mechanism.


Assuntos
Adipogenia/efeitos dos fármacos , Tecido Adiposo/efeitos dos fármacos , Inibidores Enzimáticos/toxicidade , Inflamação/induzido quimicamente , Zimosan/toxicidade , Animais , Materiais Biocompatíveis/farmacologia , Colágeno/farmacologia , Combinação de Medicamentos , Imuno-Histoquímica , Laminina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteoglicanas/farmacologia , Resultado do Tratamento
10.
FASEB J ; 20(3): 565-7, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16436466

RESUMO

We have developed a chamber model of islet engraftment that optimizes islet survival by rapidly restoring islet-extracellular matrix relationships and vascularization. Our aim was to assess the ability of syngeneic adult islets seeded into blood vessel-containing chambers to correct streptozotocin-induced diabetes in mice. Approximately 350 syngeneic islets suspended in Matrigel extracellular matrix were inserted into chambers based on either the splenic or groin (epigastric) vascular beds, or, in the standard approach, injected under the renal capsule. Blood glucose was monitored weekly for 7 weeks, and an intraperitoneal glucose tolerance test performed at 6 weeks in the presence of the islet grafts. Relative to untreated diabetic animals, glycemic control significantly improved in all islet transplant groups, strongly correlating with islet counts in the graft (P<0.01), and with best results in the splenic chamber group. Glycemic control deteriorated after chambers were surgically removed at week 8. Immunohistochemistry revealed islets with abundant insulin content in grafts from all groups, but with significantly more islets in splenic chamber grafts than the other treatment groups (P<0.05). It is concluded that hyperglycemia in experimental type 1 diabetes can be effectively treated by islets seeded into a vascularized chamber functioning as a "pancreatic organoid."


Assuntos
Glicemia/análise , Diabetes Mellitus Experimental/cirurgia , Transplante das Ilhotas Pancreáticas/instrumentação , Engenharia Tecidual/instrumentação , Transplante Heterotópico/instrumentação , Animais , Colágeno , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Combinação de Medicamentos , Teste de Tolerância a Glucose , Sobrevivência de Enxerto , Virilha , Insulina/uso terapêutico , Rim , Laminina , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica , Proteoglicanas , Baço , Transplante Homólogo
11.
Br J Plast Surg ; 58(8): 1104-14, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16043148

RESUMO

UNLABELLED: The distribution of hypoxic cells in an in vivo tissue engineering chamber was investigated up to 28 days post-implantation. METHODS: Arteriovenous loops were constructed and placed into bi-valved polycarbonate chambers containing 2 x 10(6) rat fibroblasts in basement membrane gel (BM gel). Chambers were inserted subcutaneously in the groin of male rats and harvested at 3 (n = 6), 7 (n = 6), 14 (n = 4) or 28 (n = 4) days. Ninety minutes before harvest, pimonidazole (60 mg/kg) was injected intraperitoneally. Chamber tissue was removed, immersion fixed, paraffin embedded, sectioned and stained immunohistochemically using hypoxyprobe-1 Mab that detects reduced pimonidazole adducts forming in cells, where pO2 < 10 mmHg. RESULTS: At 3 days a fibrin clot/BM gel framework filled the chamber. Seeded fibroblasts had largely died. The majority of 3 day chambers did not demonstrate tissue growth from the AV loop nor was pimonidazole binding present in these chambers. In one chamber in which tissue growth had occurred strong pimonidazole binding was evident within the new tissue. In four out of six 7 day chambers a broader proliferative zone existed extending up to 0.4 mm (approximately) from the AV loop endothelium which demonstrated intense pimonidazole binding. The two remaining 7 day chambers displayed even greater tissue growth (leading edge > 0.7 mm from the AV loop endothelium), but very weak or no pimonidazole binding. At 14 and 28 days the fibrin/BM gel matrix was replaced by mature vascularised connective tissue that did not bind pimonidazole. CONCLUSION: Employing a tissue engineering chamber, new tissue growth extending up to 0.4 mm from the AV loop endothelium (chambers < or = 7 days) demonstrated intense pimonidazole binding and, therefore, hypoxia. Tissue growth greater than 0.5 mm from the AV loop endothelium (7-28 days chambers) did not exhibit pimonidazole binding due to a significant increase in the number of new blood vessels and was, therefore, adequately oxygenated.


Assuntos
Hipóxia Celular/fisiologia , Nitroimidazóis/farmacocinética , Engenharia Tecidual/instrumentação , Animais , Derivação Arteriovenosa Cirúrgica , Biomarcadores/metabolismo , Divisão Celular/fisiologia , Movimento Celular/fisiologia , Células Cultivadas , Cultura em Câmaras de Difusão , Endotélio Vascular , Fibrina , Fibroblastos , Géis , Masculino , Ratos , Ratos Sprague-Dawley
12.
Kidney Int ; 60(2): 786-96, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11473663

RESUMO

BACKGROUND: Organs used for transplantation may experience long periods of cold ischemic preservation and consequently oxygen free radical-mediated damage following reperfusion. Lecithinized superoxide dismutase (lec-SOD) is a novel free radical scavenger that has been shown to bind with high affinity to cell membranes. The aim of this study was to determine whether lec-SOD bound to endothelial cells under organ preservation conditions to mediate direct antioxidant activity at the endothelial cell surface and thus offer protection against the harmful effects of ischemia/reperfusion injury. METHODS: An in vitro study was performed on large vessel endothelial cells (HUVEC) and a human microvascular endothelial cell line HMEC-1, to investigate the potential therapeutic benefits of incorporating lec-SOD into organ preservation solution. A cold hypoxia/reoxygenation system was developed to examine lec-SOD binding affinity to endothelial cells, protection against hypoxia/reoxygenation-induced cell death, and neutrophil adhesion. RESULTS: Lec-SOD bound to endothelial cells with higher affinity than unmodified recombinant human superoxide dismutase (rhSOD) and significantly protected both HUVEC and HMEC-1 from cell death following 27 hours of cold hypoxia (P < 0.01). Furthermore, neutrophil adhesion to the endothelium stimulated by hypoxia and reoxygenation was significantly inhibited by treatment with lec-SOD but not by lecithin or rhSOD (P < 0.01). Analysis by flow cytometry demonstrated that E-selectin and ICAM-1 were up-regulated by hypoxia/reoxygenation that was inhibited in part by lec-SOD. CONCLUSIONS: The results from this study suggest that incorporation of lec-SOD into organ preservation solutions provides effective protection to endothelial cells against cold ischemia and reperfusion injury following transplantation.


Assuntos
Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Fosfatidilcolinas/farmacologia , Traumatismo por Reperfusão/metabolismo , Superóxido Dismutase/farmacologia , Antioxidantes/farmacologia , Adesão Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Células Cultivadas , Criopreservação , Selectina E/metabolismo , Citometria de Fluxo , Radicais Livres , Humanos , Soluções Hipertônicas/química , Soluções Hipertônicas/farmacologia , Molécula 1 de Adesão Intercelular/metabolismo , Transplante de Rim , Neutrófilos/citologia , Soluções para Preservação de Órgãos/química , Soluções para Preservação de Órgãos/farmacologia , Veias Umbilicais/citologia
13.
Tissue Eng ; 7(1): 73-80, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11224925

RESUMO

Isogenous fibroblasts derived from the skin of inbred Sprague-Dawley rats were cultured in vitro, labeled with bisbenzamide (BB) or carboxyfluorescein diacetate (CFDA), and seeded into polycarbonate growth chambers. After 24 h incubation in vitro, the chambers, either empty or containing an arteriovenous (AV) shunt, were implanted subcutaneously into the inguinal region of Sprague-Dawley rats and examined by fluorescence microscopy 2 or 7 days later. The AV shunt remained patent in all experiments. The density of labeled cells on the chamber surface in all chambers decreased in the first 2 days after insertion. At 7 days, the cell density in the empty chambers had not altered from the 2-day level, but the density in the AV shunt containing chambers had increased to almost three times the day 2 level (p = 0.013). It appears that an AV shunt can induce a significant proliferation of fibroblasts implanted adjacent to it. For at least 7 days after labeling, BB and CFDA provide a simple and effective method of quantitative detection of implanted fibroblasts. It is concluded that nutrients from the AV shunt implanted in a growth chamber result in a significant increase in the number of viable, matrix-synthesizing cells, compared with AV shunt-free controls.


Assuntos
Derivação Arteriovenosa Cirúrgica , Engenharia Biomédica/métodos , Fibroblastos/citologia , Animais , Bisbenzimidazol/metabolismo , Contagem de Células , Sobrevivência Celular , Células Cultivadas , Fibroblastos/metabolismo , Fluoresceínas/metabolismo , Corantes Fluorescentes/metabolismo , Humanos , Masculino , Microscopia de Fluorescência , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Pele/citologia
14.
Ann N Y Acad Sci ; 944: 429-42, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11797691

RESUMO

In a recently described model for tissue engineering, an arteriovenous loop comprising the femoral artery and vein with interposed vein graft is fabricated in the groin of an adult male rat, placed inside a polycarbonate chamber, and incubated subcutaneously. New vascularized granulation tissue will generate on this loop for up to 12 weeks. In the study described in this paper three different extracellular matrices were investigated for their ability to accelerate the amount of tissue generated compared with a no-matrix control. Poly-D,L-lactic-co-glycolic acid (PLGA) produced the maximal weight of new tissue and vascularization and this peaked at two weeks, but regressed by four weeks. Matrigel was next best. It peaked at four weeks but by eight weeks it also had regressed. Fibrin (20 and 80 mg/ml), by contrast, did not integrate with the generating vascularized tissue and produced less weight and volume of tissue than controls without matrix. The limiting factors to growth appear to be the chamber size and the capacity of the neotissue to integrate with the matrix. Once the sides of the chamber are reached or tissue fails to integrate, encapsulation and regression follow. The intrinsic position of the blood supply within the neotissue has many advantages for tissue and organ engineering, such as ability to seed the construct with stem cells and microsurgically transfer new tissue to another site within the individual. In conclusion, this study has found that PLGA and Matrigel are the best matrices for the rapid growth of new vascularized tissue suitable for replantation or transplantation.


Assuntos
Vasos Sanguíneos/crescimento & desenvolvimento , Matriz Extracelular/fisiologia , Engenharia Tecidual , Animais , Colágeno , Combinação de Medicamentos , Imuno-Histoquímica , Ácido Láctico , Laminina , Masculino , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros , Proteoglicanas , Ratos , Ratos Sprague-Dawley
15.
Tissue Eng ; 6(6): 595-603, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11103081

RESUMO

A major requirement for the microsurgical repair of contour defects of the skin, for example, following removal of a skin cancer on the face, is a mass of vascularised subcutaneous tissue. Such tissue can be generated in vivo using basic tissue engineering principles. In previous studies in our laboratory, we have used a model comprising an arteriovenous (AV) shunt loop sandwiched in artificial dermis, placed in a cylindrical plastic growth chamber, and inserted subcutaneously to grow new connective tissue progressively up to 4 weeks. To learn more about the basic growth characteristics with this model, the same AV shunt loop within a chamber without added extracellular matrix was inserted subcutaneously into the groins of rats for 2, 4, or 12 weeks (n = 5 per group). There was a progressive increase in the mass and volume of tissue such that the chamber was two-thirds full after 12 weeks. Histological examination showed that at 2 weeks there was evidence of fibroblast and vascular outgrowth from the AV shunt, with the formation of granulation tissue, surrounded by a mass of coagulated exudate. At 4 weeks the connective tissue deposition was more extensive, with a mass of more mature granulation tissue containing considerable collagen. By 12 weeks there was an extensive, well vascularized mass of mature fibrous tissue. The blood vessels and residual adventitia of the AV shunt were the likely source of growth factors and of the cells which populated the chamber with new maturing connective tissue. A patent AV shunt in an isolated chamber appears to be the minimal requirement for the generation of new vascularized tissue that is potentially suitable for microsurgical transplantation.


Assuntos
Derivação Arteriovenosa Cirúrgica , Tecido Conjuntivo/fisiologia , Matriz Extracelular/fisiologia , Neovascularização Fisiológica , Animais , Fístula Arteriovenosa , Derivação Arteriovenosa Cirúrgica/métodos , Tecido Conjuntivo/patologia , Artéria Femoral , Veia Femoral , Masculino , Ratos , Ratos Sprague-Dawley , Regeneração/fisiologia
16.
Ann Plast Surg ; 44(3): 304-10, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10735223

RESUMO

Storage of skin flaps in the cold before replantation increases their tolerance to ischemic damage. Rat epigastric skin flaps were perfused immediately before 2 days of cold ischemia with 3 ml of normal saline containing either 10 U per milliliter of heparin (group 1, N = 11) or normal saline (group 2, N = 10), or stored without perfusion (group 3, N = 6), and replanted. Flap viability was assessed 7 days later. The mean flap survival in groups 1, 2, and 3 was 73% (p<0.01 compared with group 2), 10%, and 33% respectively. Intravascular fibrin deposits were detected histochemically 5 minutes before reperfusion in nonperfused flaps and 5 minutes after reperfusion in saline-perfused flaps, but not in flaps perfused with heparinized saline. Angiography revealed evidence of no reflow in the first 5 minutes of reperfusion in saline-perfused flaps, but normal blood flow in heparinized saline-perfused flaps. Tissue water content, myeloperoxidase activity, and hydroperoxide levels after 1 and 24 hours of reperfusion were not significantly different in flaps perfused with heparinized saline and normal saline. These findings indicate that in skin flaps perfused before ischemia, flaps perfused with heparinized saline survive significantly better than flaps perfused with normal saline. They also survive better than nonperfused flaps but the improvement is not significant.


Assuntos
Heparina/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Retalhos Cirúrgicos/irrigação sanguínea , Animais , Temperatura Baixa , Masculino , Ratos , Ratos Sprague-Dawley , Reperfusão , Pele/irrigação sanguínea , Cloreto de Sódio
17.
Br J Plast Surg ; 52(6): 458-61, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10673922

RESUMO

Skin defects in the leg can be among the most difficult to cover. Split skin grafting of such defects can be complicated by delayed healing and poor cosmesis and this has led to the description of several local flap techniques. Here a technique of V-Y flap closure is described based laterally on a random fascial pedicle. Twenty patients aged from 51 to 85 years had flaps for skin closure after excision of skin tumours, 17 of them in the middle or lower third of the leg. All but one were performed under local anaesthetic, seven as day cases and eight with an overnight stay. No patient was excluded because of medical conditions or skin quality and two patients had significant lymphoedema. A single V-Y flap was used in each case and was found to have much greater mobility than previously described similar flaps. Cosmetic results, and in particular contour preservation, were found to be excellent. There were no complete flap losses but four patients had delayed healing, two related to partial flap necrosis. Four patients had wound infections, one requiring readmission for intravenous antibiotics but no patient had further surgery. The fasciocutaneous V to Y island flap was found to be a very satisfactory method of wound closure in the leg with an acceptable complication rate and excellent cosmetic results.


Assuntos
Procedimentos de Cirurgia Plástica/métodos , Neoplasias Cutâneas/cirurgia , Retalhos Cirúrgicos , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Perna (Membro)/cirurgia , Pessoa de Meia-Idade , Complicações Pós-Operatórias
18.
Br J Plast Surg ; 50(5): 343-8, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9245868

RESUMO

In three groups of rabbits, the rectus femoris muscle was subjected to 4 hours of total ischaemia. In Group 1 (normothermia, n = 5) the core temperature was maintained within the range 36-38 degrees C for the duration of ischaemia. In Group 2 (total hypothermia, n = 5) the core temperature was allowed to fall to 31.5-33.5 degrees C. In Group 3 (muscle only hypothermia, n = 5) core temperature was maintained as in Group 1 but the muscle temperature was allowed to fall to 29.5-31.5 degrees C. After 24 hours of reperfusion the muscles were harvested and measurements made of muscle viability, oedema and myeloperoxidase content. The mean (s.e.m.) muscle viability of Group 1, 19.5 (3.8)%, was significantly less than that of both Group 2, 86.0 (2.0)%, and Group 3, 87 (4.1)%, (P < 0.001). Muscle oedema and myeloperoxidase levels were elevated in all experimental groups, but differences were not significant. These findings indicate that ischaemia-reperfusion injury in skeletal muscle in this model is highly temperature-sensitive, small reductions in muscle temperature during ischaemia providing significant protection against ischaemia-reperfusion injury.


Assuntos
Hipotermia Induzida , Músculo Esquelético/irrigação sanguínea , Traumatismo por Reperfusão/prevenção & controle , Animais , Temperatura Corporal , Edema/prevenção & controle , Feminino , Masculino , Músculo Esquelético/enzimologia , Músculo Esquelético/patologia , Doenças Musculares/prevenção & controle , Peroxidase/metabolismo , Coelhos , Traumatismo por Reperfusão/patologia , Temperatura
19.
Plast Reconstr Surg ; 99(2): 378-85, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9030143

RESUMO

Vascular pedicle implantation into the subdermal level of the skin induces an angiogenic response that can be sufficient to artificially create or "prefabricate" an axial-pattern flap suitable for island pedicle or free-flap transfer. This technique allows the creation of large, thin skin flaps that retain the qualities of the donor-site skin. Three cases are presented in which such thin flaps have been created to cover defects, one on the knee and two on the face. While the reconstructions are satisfactory, difficulties were encountered with venous insufficiency in the flaps after the second-stage transfer. We believe that the complexity and staged nature of these procedures limit their application to highly selected patients, but their role probably lies in the transfer of supraclavicular skin for the reconstruction of facial defects.


Assuntos
Retalhos Cirúrgicos/irrigação sanguínea , Retalhos Cirúrgicos/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
Scand J Plast Reconstr Surg Hand Surg ; 30(4): 299-305, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8976025

RESUMO

Reconstruction of a full thickness defect of the abdominal or chest wall requires a combination of a rigid or semi-rigid layer and skin cover. The tensor fasciae latae (TFL) flap is unique in that it provides both of these in substantial quantities, but the most difficult aspect of using this flap in the anterior chest and abdomen is finding suitable recipient vessels. We describe a series of nine cases in which full thickness defects of the chest and abdominal wall were repaired using free vascularised TFL flaps. The recipient vessels included the gastroepiploic vessels (n = 2), the deep inferior epigastric artery (n = 3), the internal mammary artery (n = 2), and the superior thyroid and acromiothoracic arteries (n = 1 each). The gastroepiploic and internal mammary vessels are preferred because of their reliability and because the flap pedicle enters the centre of the deep surface of the flap so that if these vessels are used, circumferential tight closure of the fascial layer can be achieved, with consequent decreased risk of vessel kinking and future herniation.


Assuntos
Músculos Abdominais/cirurgia , Retalhos Cirúrgicos/métodos , Cirurgia Torácica , Adulto , Idoso , Artérias , Evolução Fatal , Feminino , Hérnia Ventral/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Osteorradionecrose/cirurgia , Estômago/irrigação sanguínea
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