Large Grafts Research Articles

CMR diagnosis of coronary graft fistula

the patient is a 54-year old man with a previous history of cerebral aqueduct stenosis and hydrocephalus resulting in malignant hypertension who had surgery for permanent ventriculo-peritoneal shunt. At age 41, he had coronary artery bypass graft (CABg) surgery with the right internal mammary artery anastomosed to the posterior descending artery and a saphenous vein graft to the first obtuse marginal branch. the patient was recently admitted with pneumonia that rapidly deteriorated and he went in respiratory failure requiring mechanical ventilation. A thoracic Ct investigation showed massive bilateral pulmonary infiltrates, pulmonary artery embolism and a large vein graft aneurysm with a maximal diameter of 40 mm (Figure 1 A-B). the management course was complicated with prolonged respiratory failure, persistent infection, despite negative cultures and extended hospital stay. After 50 days of slow recovery the patient was discharged with a need for home oxygen therapy. ten days later, he was re-admitted with chest pain requiring admission to the coronary care unit where severe pulmonary hypertension was diagnosed with doppler echocardiography. troponin-t was mildly elevated, 1,3 ug/l (ref <0,01), CRp was 50 mg/l and chest X-ray showed bilateral lung infiltrates and wide pulmonary vessels. At this point a systo-diastolic murmur was heard at the left lower sternal edge. with a view of potential coronary reintervention and to evaluate the pulmonary hypertension, a coronary angiogram and a pulmonary artery cathetherisation were performed. this showed a new stenosis in the left anterior descending coronary artery and the pulmonary catheterisation showed a “step-up” in oxygen saturation in the pulmonary artery, suggesting a left-to-right shunt. the vein graft aneurysm did not contribute to the coronary circulation. A cardiovascular magnetic resonance scan revealed a communication between the vein graft aneurysm and the left branch pulmonary artery (Figure 1 C-d), causing a left-to-right shunt with Qp/Qs 2:1. Biventricular systolic function was normal.

Meningeal cells influence midbrain development and the engraftment of dopamine progenitors in Parkinsonian mice

Dopaminergic neuroblasts, isolated from ventral midbrain fetal tissue, have been shown to structurally and functionally integrate, and alleviate Parkinsonian symptoms following transplantation. The use of donor tissue isolated at an age younger than conventionally employed can result in larger grafts — a consequence of improved cell survival and neuroblast proliferation at the time of implantation. However studies have paid little attention to removal of the meninges from younger tissue, due to its age-dependent tight attachment to the underlying brain. Beyond the protection of the central nervous system, the meninges act as a signaling center, secreting a variety of trophins to influence neural development and additionally impact on neural repair. However it remains to be elucidated what influence these cells have on ventral midbrain development and grafted dopaminergic neuroblasts. Here we examined the temporal role of meningeal cells in graft integration in Parkinsonian mice and, using in vitro approaches, identified the mechanisms underlying the roles of meningeal cells in midbrain development. We demonstrate that young (embryonic day 10), but not older (E12), meningeal cells promote dopaminergic differentiation as well as neurite growth and guidance within grafts and during development. Furthermore we identify stromal derived factor 1 (SDF1), secreted by the meninges and acting on the CXCR4 receptor present on dopaminergic progenitors, as a contributory mediator in these effects. These findings identify new and important roles for the meningeal cells, and SDF1/CXCR4 signaling, in ventral midbrain development as well as neural repair following cell transplantation into the Parkinsonian brain.

Vascularization in bone tissue engineering constructs.

Vascularization of large bone grafts is one of the main challenges of bone tissue engineering (BTE), and has held back the clinical translation of engineered bone constructs for two decades so far. The ultimate goal of vascularized BTE constructs is to provide a bone environment rich in functional vascular networks to achieve efficient osseointegration and accelerate restoration of function after implantation. To attain both structural and vascular integration of the grafts, a large number of biomaterials, cells, and biological cues have been evaluated. This review will present biological considerations for bone function restoration, contemporary approaches for clinical salvage of large bone defects and their limitations, state-of-the-art research on the development of vascularized bone constructs, and perspectives on evaluating and implementing novel BTE grafts in clinical practice. Success will depend on achieving full graft integration at multiple hierarchical levels, both between the individual graft components as well as between the implanted constructs and their surrounding host tissues. The paradigm of vascularized tissue constructs could not only revolutionize the progress of BTE, but could also be readily applied to other fields in regenerative medicine for the development of new innovative vascularized tissue designs.

A Novel Technique of Defattening Large Full Thickness Skin Grafts.

Sir, Full Thickness Skin Graft (FTSG) holds an irreplaceable position in a reconstructive and aesthetic surgeon’s armamentarium. Particularly for coverage of defects over face and hands, FTSG provides superior aesthetic and functional result as compared to the split thickness graft. FTSG is harvested free hand with a scalpel and invariably tends to include some of the underlying fat with it. Defattening of the graft is an important step to avoid fat necrosis [1] and to facilitate approximation of the dermis to wound bed which is essential for the revascularisation of the graft and eventually affects the ‘take’ [2]. Placing the skin graft under tension over a convex surface is a prerequisite for optimal defattening. As originally described in text [3] and as per the conventional teaching, the FTSG has always been defattened by stretching it upside down over the tip of surgeon’s index finger of non dominant hand while cutting with a sharp scissors [Table/Fig-1] [3]. This may at times lead to inadequate or irregular defattening, may also cause buttonholing and may be quite time consuming for large area grafts. [Table/Fig-1]: Conventional technique of defattening of FTSG We have tried a novel way of defattening of a large FTSG by placing it over the dorsum of the non dominant hand of the assistant with dermal side facing upwards and defattening by using sharp scissors [Table/Fig-2a,b]. This technique has been particularly found useful for the large FTSG required for resurfacing of extensive facial post burn scars as the sheer size of the graft renders it unmanageable to defattening by conventional technique. Other advantages are that it is easier and faster and provides better outcome in terms of more uniform defattening of the FTSG and also prevents any inadvertent buttonholing of the precious graft. It is worth noting that this technique keeps both hands of the surgeon free to work. [Table/Fig-2a,b]: Our technique for defattening of large grafts placing the graft on back of the assistant’s hand: a) relative position of surgeon and assistant; b) the way graft is held over back of the hand of assistant while fat is trimmed off In our practice we cover large post burn scars over face and neck with large FTSGs harvested from lower abdomen with or without the use of tissue expansion. These grafts may sometimes be of dimensions upto 25 x 10 cm. As the surgery is being done for aesthetic effect, buttonholing and graft necrosis due to inadequate defattening is not acceptable. Defattening of such large grafts proves to be a challenge. The authors have been using this technique routinely for the cases requiring large size full thickness grafts (in more than 100 patients till now) with excellent outcomes and never had complications associated with the conventional technique as discussed above [Table/Fig-3]. [Table/Fig-3]: Cases of post burn scar over face resurfaced with large FTSG from lower abdomen Thus we see that with this modified technique, one can defatten FTSG with precision in just few minutes and it makes the surgeon’s life easier while also giving a superior aesthetic result as compared to the conventional technique.

The Role of Fibers in the Femoral Attachment of the Anterior Cruciate Ligament in Resisting Tibial Displacement

PurposeThe purpose was to clarify the load-bearing functions of the fibers of the femoral anterior cruciate ligament (ACL) attachment in resisting tibial anterior drawer and rotation.MethodsA sequential cutting study was performed on 8 fresh-frozen human knees. The femoral attachment of the ACL was divided into a central area that had dense fibers inserting directly into the femur and anterior and posterior fan-like extension areas. The ACL fibers were cut sequentially from the bone: the posterior fan-like area in 2 stages, the central dense area in 4 stages, and then the anterior fan-like area in 2 stages. Each knee was mounted in a robotic joint testing system that applied tibial anteroposterior 6-mm translations and 10° or 15° of internal rotation at 0° to 90° of flexion. The reduction of restraining force or moment was measured after each cut.ResultsThe central area resisted 82% to 90% of the anterior drawer force; the anterior fan-like area, 2% to 3%; and the posterior fan-like area, 11% to 15%. Among the 4 central areas, most load was carried close to the roof of the intercondylar notch: the anteromedial bundle resisted 66% to 84% of the force and the posterolateral bundle resisted 16% to 9% from 0° to 90° of flexion. There was no clear pattern for tibial internal rotation, with the load shared among the posterodistal and central areas near extension and mostly the central areas in flexion.ConclusionsUnder the experimental conditions described, 66% to 84% of the resistance to tibial anterior drawer arose from the ACL fibers at the central-proximal area of the femoral attachment, corresponding to the anteromedial bundle; the fan-like extension fibers contributed very little. This work did not support moving a single-bundle ACL graft to the side wall of the notch or attempting to cover the whole attachment area if the intention was to mimic how the natural ACL resists tibial displacements.Clinical RelevanceThere is ongoing debate about how best to reconstruct the ACL to restore normal knee function, including where is the best place for ACL graft tunnels. This study found that the most important area on the femur, in terms of resisting displacement of the tibia, was in the central-anterior part of the femoral ACL attachment, near the roof of the intercondylar notch. The testing protocol did not lead to data that would support using a large ACL graft tunnel that attempts to cover the whole natural femoral attachment area.

Tissue engineering of a vascularized bone graft of critical size with an osteogenic and angiogenic factor-based in vivo bioreactor.

Engineering a large vascularized bone graft is a much greater challenge than engineering small bone tissues. Although this is essentially feasible through an osteogenic factor-based in vivo bioreactor technique, the ossification needs improving. This study was aimed to investigate the possibility and efficacy of ectopic cultivation of sizeable bone grafts with large angiogenic and osteogenic factor-loaded natural bovine bone mineral (NBBM) scaffolds. For this purpose, six groups of sizeable composite scaffolds were constructed, consisting of a titanium mesh cage of NBBM or a mixture of NBBM/autogenous bone particles (AB), which were preloaded with 660 μg recombinant human bone morphogenetic protein-7 (rhBMP-7) and/or 4 μg recombinant human vascular endothelial growth factor165 (rhVEGF165). The scaffolds were implanted in bilateral latissimus dorsi muscles in eight pigs to construct in vivo bioreactors. Sequential fluorescence labeling was then applied to trace bone formation at the early stage. The implants were retrieved 12 weeks later. The undecalcified sections were observed in turn under the fluorescence microscope and light microscope to investigate early stage osteogenesis and histology. Moreover, new bone density (BD) was measured with histomorphometry. Compared with rhBMP-7-delivered NBBM scaffolds, rhVEGF165/rhBMP-7-delivered NBBM scaffolds were with more intense intra-scaffold osteogenesis at the early stage and the ultimate sizeable bone grafts of microstructurally more lamellae and trabeculae, and quantitatively higher BD (31.93% vs. 22.37%, p<0.01). This study demonstrated that as for the endocultivation of a large bone graft with bioactive factor-based in vivo bioreactor technique, dual delivery of rhVEGF165/rhBMP-7 has synergic effects on improving early stage bone formation and subsequently bone quality and quantity of the bone grafts.

Course of the Mandibular Incisive Canal and Its Impact on Harvesting Symphysis Bone Grafts

To characterize the anatomic course of the mandibular incisive canal to define parameters for harvesting autogenous bone from the symphysis of the mandible. A series of osteotomies were completed between the mental foramina in the anterior mandibles of 19 cadavers. Methylene blue dye was used to help identify the incisive canal. From the canal, distances to key adjacent landmarks were measured with a Boley gauge to 0.1 mm. Measurements included distances from the mandibular incisive canal to the buccal cortex, the lingual cortex, the inferior border of the mandible, the apices of the teeth, and the buccal cementoenamel junction (CEJ) of the teeth. The canal decreased in diameter from lateral to medial. It tended to be closer to the buccal cortical bone than to the lingual cortex (P < .001) and was, at times, directly abutting the buccal cortex (average distance to buccal cortex, 3.5 mm). The canal maintained a relatively constant distance from the apices of the teeth (approximately 7 to 8 mm), coursing inferiorly under the longer canines bilaterally. The canal became increasingly difficult to identify toward the midline, likely dispersing into microscopic tributaries. The authors suggest several modifications to the standard surgical approach to the symphysis area during the harvest of bone grafts. When the goal is to avoid the mandibular incisive canal, osteotomies should not exceed a depth of 4 mm, should be at least 5 mm anterior to the mental foramen, and 9 mm below the root apices (or 23 mm below the lowest facial CEJ) and should maintain the contour of the mandible's inferior border. Alternatively, some degree of canal compromise can be accepted and larger grafts can be obtained by increasing the depth of the harvest in the horizontal dimension or decreasing the distance from the osteotomy to the root apices (or the CEJ) in the vertical dimension.

Surgical therapies for corneal perforations: 10 years of cases in a tertiary referral hospital.

PurposeTo report surgical therapies for corneal perforations in a tertiary referral hospital.MethodsThirty-one eyes of 31 patients (aged 62.4±18.3 years) with surgically treated corneal perforations from January 2002 to July 2013 were included in this study. Demographic data such as cause of corneal perforation, surgical procedures, and visual outcomes were retrospectively analyzed.ResultsThe causes of corneal perforation (n=31) were divided into infectious (n=8, 26%) and noninfectious (n=23, 74%) categories. Infectious causes included fungal ulcer, herpetic stromal necrotizing keratitis, and bacterial ulcer. The causes of noninfectious keratopathy included corneal melting after removal of a metal foreign body, severe dry eye, lagophthalmos, canaliculitis, the oral anticancer drug S-1, keratoconus, rheumatoid arthritis, neurotrophic ulcer, atopic keratoconjunctivitis, and unknown causes. Initial surgical procedures included central large corneal graft (n=17), small corneal graft (n=7), and amniotic membrane transplantation (n=7). In two cases the perforation could not be sealed during the first surgical treatment and required subsequent procedures. All infectious keratitis required central large penetrating keratoplasty to obtain anatomical cure. In contrast, several surgical options were used for the treatment of noninfectious keratitis. After surgical treatment, anatomical cure was obtained in all cases. Mean postoperative best corrected visual acuity was better at 6 months (logMAR 1.3) than preoperatively (logMAR 1.8).ConclusionSurgical therapies for corneal perforations in our hospital included central large lamellar/penetrating keratoplasty, small peripheral patch graft, and amniotic membrane transplantation. All treatments were effective. Corneal perforation due to the oral anticancer drug S-1 is newly reported.

Engineering a vascularized collagen-β-tricalcium phosphate graft using an electrochemical approach

Vascularization of three-dimensional large synthetic grafts for tissue regeneration remains a significant challenge. Here we demonstrate an electrochemical approach, named the cell electrochemical detachment (CED) technique, to form an integral endothelium and use it to prevascularize a collagen-β-tricalcium phosphate (β-TCP) graft. The CED technique electrochemically detached an integral endothelium from a gold-coated glass rod to a collagen-infiltrated, channeled, macroporous β-TCP scaffold, forming an endothelium-lined microchannel containing graft upon removal of the rod. The in vitro results from static and perfusion culture showed that the endothelium robustly emanated microvascular sprouting and prevascularized the entire collagen/β-TCP integrated graft. The in vivo subcutaneous implantation studies showed that the prevascularized collagen/β-TCP grafts established blood flow originating from the endothelium-lined microchannel within a week, and the blood flow covered more areas in the graft over time. In addition, many blood vessels invaded the prevascularized collagen/β-TCP graft and the in vitro preformed microvascular networks anastomosed with the host vasculature, while collagen alone without the support of rigid ceramic scaffold showed less blood vessel invasion and anastomosis. These results suggest a promising strategy for effectively vascularizing large tissue-engineered grafts by integrating multiple hydrogel-based CED-engineered endothelium-lined microchannels into a rigid channeled macroporous scaffold.

Tumor necrosis factor improves vascularization in osteogenic grafts engineered with human adipose-derived stem/stromal cells.

The innate immune response following bone injury plays an important role in promoting cellular recruitment, revascularization, and other repair mechanisms. Tumor necrosis factor-α (TNF) is a prominent pro-inflammatory cytokine in this cascade, and has been previously shown to improve bone formation and angiogenesis in a dose- and timing-dependent manner. This ability to positively impact both osteogenesis and vascular growth may benefit bone tissue engineering, as vasculature is essential to maintaining cell viability in large grafts after implantation. Here, we investigated the effects of exogenous TNF on the induction of adipose-derived stem/stromal cells (ASCs) to engineer pre-vascularized osteogenic tissue in vitro with respect to dose, timing, and co-stimulation with other inflammatory mediators. We found that acute (2-day), low-dose exposure to TNF promoted vascularization, whereas higher doses and continuous exposure inhibited vascular growth. Co-stimulation with platelet-derived growth factor (PDGF), another key factor released following bone injury, increased vascular network formation synergistically with TNF. ASC-seeded grafts were then cultured within polycaprolactone-fibrin composite scaffolds and implanted in nude rats for 2 weeks, resulting in further tissue maturation and increased angiogenic ingrowth in TNF-treated grafts. VEGF-A expression levels were significantly higher in TNF-treated grafts immediately prior to implantation, indicating a long-term pro-angiogenic effect. These findings demonstrate that TNF has the potential to promote vasculogenesis in engineered osteogenic grafts both in vitro and in vivo. Thus, modulation and/or recapitulation of the immune response following bone injury may be a beneficial strategy for bone tissue engineering.

Perioperative changes in nutritional parameters and impact of graft size in patients undergoing adult living donor liver transplantation.

Derangements of various serum biochemical nutritional/metabolic parameters are common in patients with end-stage liver disease who undergo liver transplantation (LT). The aim of this study was to explain the benefit of LT with respect to parameter changes and to examine the impact of the graft-to-recipient weight ratio (GRWR) on such changes. We investigated each parameter's course in 208 adult recipients for 1 year after living donor LT and analyzed changes in the parameters with a GRWR of 0.8% as the cutoff point. Bonferroni corrections were applied to account for multiple testing. Liver disease-induced high pretransplant ammonia and tyrosine levels and low branched-chain amino acids to tyrosine ratio (BTR) and zinc levels normalized within 2 weeks after transplantation, and the total lymphocyte count (TLC) normalized within 2 months, whereas low pretransplant prealbumin levels took 1 year to normalize. Branched-chain amino acids (BCAA), zinc, and TLC levels transiently dropped shortly after transplantation and then were corrected later. An accelerated recovery of ammonia and tyrosine levels and the BTR were found with larger grafts, especially early after transplantation, whereas zinc, prealbumin, BCAA, and TLC levels recovered regardless of the graft size. In conclusion, graft size had little effect on the recovery of nutritional/metabolic parameters except for ammonia and tyrosine levels.

Abdominal Compartment Syndrome: An Underrated Complication in Pediatric Kidney Transplantation

The transplantation of a large kidney in small children can lead to many complications, including an underrated complication known as abdominal compartment syndrome (ACS), which is defined as intra-abdominal pressure (IAP) ≥20 mm Hg with dysfunction of at least one thoracoabdominal organ. Presenting signs of ACS include firm tense abdomen, increased peak inspiratory pressures, oliguria, and hypotension. Between June 1, 1985, and September 30, 2013, our center performed 420 kidney transplants (deceased/living related donors: 381/39) in 314 pediatric recipients (female/male: 147/167). ACS occurred in 9 pediatric patients (weight <15 kg) who received a large kidney from adult donors. In 1 case, the patient underwent abdominal decompression with re-exploration and closure with mesh in the immediate postoperative period. In a second case, the patient developed a significant respiratory compromise with hemodynamic instability necessitating catecholamines, sedation, and assisted ventilation. For small children transplanted with a large kidney, an early diagnosis of ACS represents a critical step. From 2005 we have measured IAP during transplantation via urinary bladder pressure, and immediately after wound closure we use intraoperative and postoperative duplex sonography to value flow dynamics changes. We recommend that bladder pressure should be routinely checked in small pediatric kidney recipients who are transplanted with a large graft.

Targeting survival pathways to create infarct-spanning bridges of human embryonic stem cell–derived cardiomyocytes

Generating myocyte grafts that bridge across infarcts could maximize their functional impact and best utilize small numbers of stem cells. To date, however, graft survival within acute infarcts has not been feasible. To enhance intrainfarct graft viability, human embryonic stem cell-derived cardiomyocytes (hESC-CMs) were pretreated before implantation with cobalt protoporphyrin (CoPP), a pharmacologic inducer of cytoprotective heme oxygenase-1. After preculturing with CoPP (vs phosphate-buffered saline), hESC-CMs were injected intramyocardially into acutely infarcted rat hearts, using directed injections to span the infarct. A further group received CoPP-pretreated hESC-CMs plus 4 weekly doses of systemic CoPP to prolong exposure to cytoprotectants. Two control groups with infarcts received vehicle-only intramyocardial injections or weekly systemic CoPP without cell therapy. Postinfarct ventricular function was gauged by echocardiography and graft size quantified at 8 weeks by histomorphometry. CoPP-preconditioned hESC-CMs formed stable grafts deep within infarcted myocardium, while grafts without CoPP exposure survived mainly at the infarct periphery. Fractional shortening was improved at 4 and 8 weeks in all hearts receiving cell therapies (P<.01 vs vehicle-only injections). CoPP treatment of both graft hESC-CMs and recipient animals resulted in the largest grafts, highest fractional shortening, preserved wall thickness, and reduced infarct dimensions. Cellular therapy delivered acutely after infarction significantly improved postinfarct ventricular function at 1 and 2 months. CoPP pretreatment of cells resulted in stable hESC-CM grafts within infarcted myocardium. This design enables construction of directionally oriented, infarct-spanning bands of new cardiomyocytes that might further improve functional restoration as engrafted myocytes proliferate and mature.

Porcine acellular dermal matrix for delayed abdominal wall closure after pediatric liver transplantation.

Children are one of the groups with the highest mortality rate on the waiting list for LT. Primary closure of the abdominal wall is often impossible in the pediatric population, due to a size mismatch between a large graft and a small recipient. We present a retrospective cohort study of six pediatric patients, who underwent delayed abdominal wall closure with a biological mesh after LT, and in whom early closure was impossible. A non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) Reconstructive Tissue Matrix; LifeCell Corp, Bridgewater, NJ, USA) was used in all of the cases of the series. After a mean follow-up of 26 months (21-32 months), all patients were asymptomatic, with a functional abdominal wall after physical examination. Non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) ) is a good alternative for delayed abdominal wall closure after pediatric LT. Randomized controlled trials are necessary to determine the best moment and the best technique for abdominal wall closure.

Prognostic Value of Coronary CTA in Coronary Bypass Patients: A Long-Term Follow-Up Study

The goal of this study was to determine the long-term prognostic value of coronary computed tomography angiography (CTA) in a large coronary artery bypass graft (CABG) population. Coronary CTA has shown prognostic utility in patients without previous revascularization. However, prognostication with coronary CTA in CABG patients has not been fully assessed. Between March 2005 and April 2009, 887 consecutive CABG patients (mean age 66.8 ± 8.4 years) were considered for the inclusion in the study. Patients were classified by the number of unprotected coronary territories (UCTs) and a summary of native vessel disease and graft patency: the coronary artery protection score (CAPS). A primary endpoint (cardiovascular [CV] death, nonfatal myocardial infarction [MI]) and a secondary combined adverse events endpoint (CV death, MI, unstable angina, and late revascularizations) were recorded. Among the 887 evaluated, 166 did not meet the inclusion criteria. The final study population consisted of 721 subjects. Ten patients were excluded for unevaluable coronary CTA images. Of the remaining 711 patients, follow-up (mean 73.5 ± 14 months) was obtained in 698. Three hundred forty-seven events were recorded. By univariable analysis, the strongest coronary CTA predictors of events were UCT 2 and 3 (hazard ratio [HR] for CV death/MI: 7.5 and 10.19, p < 0.0001 and p < 0.0003, respectively) and CAPS 4 (HR for CV death/MI: 24.1, p < 0.0001). A high number of UCTs was also a strong multivariable independent predictor of CV death/MI (HR: 7.78 and 10.18 for UCT 2 and 3, p < 0.0001 and p < 0.0007, respectively). Cumulative survival rates for CV death/MI and composite adverse CV events were 86% and 73% with UCT 0, 84% and 49% with UCT 1, 53% and 3% with UCT 2, and 29% and 0% with UCT 3, respectively. Coronary CTA appears to be a promising tool for long-term risk stratification of CABG patients. The UCT score has significant prognostic value to predict CV deaths/MI.

Impact of season and grafter skill on nucleus retention and pearl oyster mortality rate in Pinctada margaritifera aquaculture

The mollusc Pinctada margaritifera is the top economic aquaculture species in French Polynesia (export value) and forms the basis of the black pearl industry. Mass production of this unique gem, produced by a living organism, relies on a surgical operation requiring tissue from a donor pearl oyster to be grafted, together with a nucleus made of shell, into the gonad of a receiving pearl oyster. This technique is performed by expert grafters, whose work constitutes the first step influencing pearl farm production yield. This study makes the first report of effects mediated by individual grafters and by the season of grafting on three rates scored at 45 days post operation: nucleus retention, nucleus rejection and pearl oyster mortality. These results were obtained in a very large scale grafting experiment, designed and conducted in a single culture site in the atoll of Arutua (Tuamotu Archipelago) and involving a total of 52,910 grafts performed by ten professional grafters, during two contrasting seasons: autumn (four grafting experiments) and spring (three grafting experiments). Statistical analysis using linear mixed-effect model for both univariate and multivariate analysis was performed. The results show a very highly significant season effect (p < 0.001), with a higher rate of nucleus retention in autumn than spring: 91.1 versus 79.4 %, respectively. A very highly significant season effect was also recorded for nucleus rejection rate (p < 0.001), which was greater in spring than in autumn: 12.6 versus 7.7 %. Oyster mortality rate was up to six times higher in spring than in autumn (p < 0.001). Within the two seasons, there was no significant difference between the grafting experiments for any of the three variables, adding robustness to the inter-season results. Taking into account this seasonal variation effect, grafter skill had a significant impact on the three variables (p < 0.001), making it possible to rank grafters from most to least efficient. Aside from skill differences between grafters, grafting in autumn may significantly increase graft success. Water temperature and its indirect consequences could be one of the most important environmental factors implicated in overall efficiency. These findings may help the potential development of an annual grafting schedule according to season/ lagoon temperature as a way to maximize production yield for the black-lipped pearl oyster industry in French Polynesia.

Risk Factors for Portal Vein Stenosis in Living-Donor Liver Transplantation

BackgroundIn living-donor liver transplantation (LDLT), the recipient's portal vein is short. Furthermore, portal vein thrombosis and stenosis can be lethal complications. We had begun the systemic administration of gabexate mesilate, a strong serine protease inhibitor, which has cytoprotective effects of endothelial cells. It is often effective on disseminated intravascular coagulation. The purpose of this study was to examine the effects of gabexate mesilate and to reveal risk factors for portal vein stenosis in LDLT. MethodsFrom 1991 to 2012, we performed 153 LDLTs. For the present cohort study, patients were divided into 2 groups. In group I, we treated with gabexate mesilate mildly (0–20 mg/kg/d; n = 29). In group II, we treated with gabexate mesilate at full dose (40 mg/kg/d; n = 124). We investigated the survival rates of both groups and performed univariate and multivariate analyses to identify the independent risk factors for portal vein stenosis. ResultsThe survival rate of group II was significantly better than that of group I (P < .05). On univariate analysis, the risk factors identified to be associated with a P value of <.20 were old age (P = .0385), heavy body weight (P = .1840), tall height (P = .1122), small lumen diameter of portal vein (P = .1379), high volume of blood loss (P = .0589), small amount of gabexate mesilate infusion (P = .0103), and large graft weight (P = .1326). On multiple logistic regression analysis we identified old age (P = .0073) and small amount of gabexate mesilate infusion (P = .0339) to be the independent risk factors for portal vein stenosis. ConclusionsOn multivariate analysis, we found that gabexate mesilate infusion contributed to the reduction of portal vein stenosis.

Jet-assisted fat transfer to the female breast: preliminary experiences

Background Nowadays, autologous fat grafting is used as a versatile tool for distinct touch-ups after performed breast reconstruction or aesthetic augmentation. Different approaches of fat harvest, filtering, and reinjection have been described in last three decades. After the first report in 2010, the Berlin Autologous Lipotransfer (BEAULI) method became one of the latest popular techniques in the field of large volume fat grafting. Preliminary experiences with the rising jet-assisted fat transfer in a large case series of two specialized European centers are presented.

D-MELD as a Predictor of Early Graft Mortality in Adult-to-Adult Living-Donor Liver Transplantation

Ensuring a good match between donor and recipient is critically important to achieve acceptable graft outcomes after living-donor liver transplantation (LDLT). Our objective was to evaluate the product of donor age and Model for End-stage Liver Disease score (D-MELD) as a predictor of graft survival after LDLT. We retrospectively evaluated the records of 355 adults who underwent LDLT for chronic liver disease and explored the relationship between D-MELD and graft outcome. High MELD score and advanced donor age were significantly associated with graft survival; D-MELD had the strongest association with in-hospital mortality. Receiver operating characteristic curve analysis showed that a D-MELD score of 462 had the highest sensitivity for predicting in-hospital mortality. Patients were allocated to three groups based on D-MELD (Class A [≤449; n=142], Class B [450-899; n=163], and Class C [≥900; n=50]) and were found to have stratified cumulative 2-year graft survivals of 94.1%, 85.3%, and 63.1%, respectively (P<0.01). Although D-MELD Class C patients had larger graft volume-to-standard liver volume ratio (P<0.01) and received right lobe grafts more often (P<0.01), they still exhibited significantly higher rates of primary graft dysfunction (P<0.01) and in-hospital mortality (P<0.01). Outcomes in D-MELD Class C were significantly worse in hepatitis C-positive patients (P<0.05). The D-MELD score is a simple and reliable predictor of early graft survival that assists the matching of donors and recipients in LDLT in adults.

The Role of Immunologic Response in Fresh Osteochondral Allografting of the Knee

Background: Osteochondral allografting, a restorative treatment option for articular cartilage lesions in the knee, involves transplantation of fresh osteochondral tissue with no tissue matching. Although retrieval studies have not consistently shown evidence of immunologic response, development of anti–human leukocyte antigen class I cytotoxic antibodies has been observed in allograft recipients. Hypothesis: Postallograft antibody formation is related to graft size and may affect clinical outcome. Study Design: Case-control study; Level of evidence, 3. Methods: This study retrospectively compared 42 antibody-positive postallograft patients with 42 antibody-negative patients. Groups were matched for age, sex, and body mass index but not intra-articular disease severity. Seventeen patients (20%) were lost to follow-up. Of the remaining 67 patients (33 antibody-positive and 34 antibody-negative), average follow-up time was 50.3 months (range, 24-165 months). Mean age was 38.1 years (range, 15-68 years) with 58% being male. Graft area was categorized as small (<5 cm2), medium (5-10 cm2), or large (>10 cm2). Graft survival and Knee Society function scores were used to measure clinical outcome. Results: Of the 84 patients, 80 had graft area data. Of 27 patients with large graft area, 19 (70%) had positive postoperative antibody screens, compared with 1 of 16 (6%) with small graft area (P < .001). Graft survival rates in the antibody-positive and antibody-negative groups were 64% and 79%, respectively (P = .152). Mean postoperative Knee Society function scores in surviving antibody-positive and antibody-negative groups were 88.3 and 84.6 points, respectively (P = .482). Conclusion: Antibody development after fresh, non-tissue-matched osteochondral allograft transplants in the knee appears related to graft size. No difference was observed in clinical outcome between groups. Graft survival is multifactorial, and the effect that the immunologic response has on clinical outcome merits further investigation.