ISSN:0738-1085    

DOI:10.1002/micr.1920150602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0738-1085    

DOI:10.1002/micr.1920150603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractWhile the sequence of biochemical and cellular events in the pathogenesis of ischemia/reperfusion injury is increasingly well understood, the way that these processes interact at the level of microcirculation to promote a distinctive reperfusion injury is less well defined. It is becoming clear, however, that these processes are initiated at the level of microcirculation, and that microcirculatory damage may precede actual tissue injury. Such damage causes microvascular no‐reflow, which in turn effectively prolongs the time of tissue ischemia and extends tissue injury. Recently, microcirculatory models have been adapted for study of the microvascular effects of ischemia/reperfusion. We have used a new in vivo mouse cremaster muscle model to study, by direct and quantitative measurement, the acute microvascular changes involved in ischemia/reperfusion. Previously described changes in capillary perfusion and venular leukocyte adhesion were observed in this model following reperfusion after prolonged ischemia (4–6 hours). We have further characterized an intense reactive vasoconstriction or vasospasm that occurs after prolonged ischemia; this vessel reaction may represent an important overlooked cause of no‐reflow following ischemia/reperfusion. This article summarizes our work in the context of other available methods that have been used to define the microvascular changes of ischemia/reperfusion. © 1994 Wiley‐L

ISSN:0738-1085    

DOI:10.1002/micr.1920150604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of intravital fluorescence microscopy in the models of the hamster dorsal skin fold chamber and the ear of the hairless mouse allows for the quantitative analysis of post‐ischemic microvascular reperfusion injury in striated muscle and skin. Prolonged periods of ischemia (4 hours in striated muscle and 6 hours in skin) are associated with (1) perfusion failure of nutritive capillaries at the onset of reperfusion (no‐reflow) and (2) activation, accumulation and microvascular adherence of white blood cells, formation of reactive oxygen metabolites and release of potent mediators (leukotrienes, platelet‐activating factor) with the consequence of increased microvascular permeability due to the loss of endothelial integrity, interstitial edema and cell damage (reflow‐paradox). Prophylactic and/or therapeutic regimens may, therefore, include improvement of capillary perfusion by hemodilution, and inhibition of leukocyte adherence, radical formation and mediator release by appropriate counteracting compounds, including anti‐oxidants, antibodies directed against adhesion molecules, leukotriene synthesis inhibitors and platelet‐activating factor receptor antagonists. © 1994 Wil

ISSN:0738-1085    

DOI:10.1002/micr.1920150605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractNeovascularization or angiogenesis is an essential yet poorly understood component of the healing process. In wound healing research, there is a lack of models enabling quantitative and continuous measurements of wound neovascul‐arization. The hairless mouse ear wound model permits quantitative measurements of wound epithelialization and neovascularization continuously throughout the healing process. On the ears of male homozygous (hr/hr) hairless mice, standardized circular full thickness dermal wounds are produced; then, using vital microscopy, these two processes are directly viewed and measured at day 0 and every third day thereafter until these are complete. This model system and its application to clinically relevant situations are reviewed. © 1994 Wiley‐Liss,

ISSN:0738-1085    

DOI:10.1002/micr.1920150606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractAngiogenesis, the formation of new blood vessels, is essential to a variety of normal and pathologic processes such as wound healing and tumor growth. In microsurgery the development of new vessels between the transferred tissue and the recipient bed is critical to the final outcome of the reconstruction.Several experimental models have been previously developed to study angiogenesis and the effect that new substances have on regulating this process, but they lack the ability to make quantitative measurements. Therefore, we have developed an animal model using the homozygous (hr/hr) hairless mouse ear; by using intravital microscopy and computer‐assisted analysis, angiogenesis can be quantitatively measured. Using this model we showed that basic fibroblast growth factor and transforming growth factor beta significantly increased total vessel length by 32% and 63%, respectively, during 20 days following subcutaneous injection. In this paper the importance of angiogenesis research to reconstructive microsurgery is presented and discussed. © 1994 Wiley‐Liss,

ISSN:0738-1085    

DOI:10.1002/micr.1920150607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractAlthough free tissue transfer success has been greatly improved by developments in operating microscopes, microsutures, microinstruments, and technique, free flap and replant failure remain a significant problem under certain adverse circumstances. The nature of these failures is often multifactorial and remains poorly understood. A greater understanding of the processes involved would provide the potential for greater pharmacological control of any adverse conditions prevailing and would thus offer the prospect of more effective adjunctive therapy in the presence of such adverse conditions. Research endeavors in this area have been hindered by the absence of good research models. The isolated rat cremaster muscle model is a recently developed model that simulates the conditions of free tissue transfer. Using this model, both thrombus formation and numerous microcirculatory parameters can be measured. The microcir‐culatory parameters studied to date include the formation of thromboembolism, capillary perfusion, vessel diameters, red blood cell velocity, leukocyte‐endothelium interaction, and microvascular leakage. The isolated rat cremaster muscle model addresses many of the shortcomings of earlier research models and offers the promise of answering at least some of the many unanswered questions relating to free flap and replant failure. © 1994 Wiley‐Lis

ISSN:0738-1085    

DOI:10.1002/micr.1920150608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA common cause of free flap and replant failure is thrombotic occlusion of the anastomosed pedicle vessel(s). Clinical observations and subsequent experimental studies showed that platelet emboli generated at the arterial anastomosis caused significant alterations in the downstream microcirculation. To study both the thrombogenic arterial (anastomosis) site and the downstream microcirculation, we developed an animal model (the isolated rat cremaster) in which we could directly view and quantitatively analyze thrombus formation and the appearance of emboli in the downstream microcirculation. Using this model we studied the effect that reducing blood flow across the arterial anastomotic site had on thrombus formation at the anastomotic site and the appearance of emboli in the downstream microcirculation. In 40 male Spra‐gue‐Dawley rats we found that reducing blood flow velocity to approximately half of normal during reperfusion nearly eliminated emboli appearing in the downstream microcirculation compared with controls, 43.9 ± 31.5 vs. 259.5 ± 117.8 emboli, respectively. We also found that the same low flow had no effect on thrombus size at the pedicle artery injury site yet significantly decreased the rate at which thrombus formation occurred (time to maximum thrombus size; low flow = 25.3 ± 8 minutes, normal flow = 6.6 ± 3 minutes). From these studies we conclude that reducing pedicle artery blood flow in our rat model during reperfusion can protect the downstream microcirculation from platelet emboli‐induced injury; however, the same reduction in flow does not affect thrombus formation in the pedicle artery. Further studies using direct observation/measurement techniques are needed for a better understanding of the mechanisms regulating free flap and replant failure. © 1994 Wiley

ISSN:0738-1085    

DOI:10.1002/micr.1920150609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe long‐term patency of the 2.5 mm mechanical microvascular anastomotic device (the Unilink system) was evaluated in 10 cases of free flap transfer in nine patients between July 1991 and July 1993. Flap survival indicated adequate patency to time of healing. All cases were considered critical end‐to‐end venous anastomoses, without a parallel conventional microvascular hand‐sewn anastomosis associated with the coupling device. The types of flaps used were seven rectus abdominous and one each of serratus anterior and lateral arm muscles and a free jejunum.There were no postoperative complications requiring reexploration. The 2.5 mm device had a rate of 100% flap take with complete healing at an average of 15 months postoper‐atively. Selected Doppler flow studies depicted the coupler device in vivo with duplex scan verification of venous patency.The 2.5 mm coupler is a versatile anastomotic device for vessels with a diameter of 2.4–3.2 mm. This expands the applicability of the UNILINK system for use in larger diameter vessels. © 1994 Wil

ISSN:0738-1085    

DOI:10.1002/micr.1920150610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBetween 1985 and 1991, 13 muscular free flaps with split thickness skin grafts (10 latissimus dorsi, 2 rectus abdominis, and 1 gracilis) were done in 12 patients to cover the weight bearing surface of the foot. Four open wounds were closed primarily and nine unstable scars were replaced with a free flap.A retrospective analysis shows that over the short term the flaps provided a complete coverage of wounds, with a 100% survival of flaps, and permitted normal weight bearing ambulation starting at 1 month postoperatively. Long‐term results show deep pressure sensation but no light touch sensation. All patients are able to wear normal shoes. Six patients (seven flaps) required further surgery to close subsequent wounds on the flaps: Three hypertrophic scars with recurrent ulcerations needed scar revisions, one child presented a fistula through the flap due to underlying osteomyelitis, and one patient presented a friction wound on the lateral malleolus requiring thinning of the flap. Two flaps presented an area of pressure necrosis through the full thickness of the flap and had to be replaced with another free flap (fasciocutaneous sensate flap) over the heel area.In conclusion, it seems that in the pediatric population, skin‐grafted muscular coverage of the weight bearing surface of the foot is a good alternative, even if more problems with hypertrophic scarring around the grafts have been found than in the adult population. In two cases, the flaps had to be replaced because of pressure necrosis over the calcaneus. Long‐term follow‐up of the sensate fasciocutaneous flaps will be needed to find out if they provide a better alternative for foot coverage. © 1994 Wiley

ISSN:0738-1085    

DOI:10.1002/micr.1920150611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY