Graft Regeneration Research Articles

Partial Inhibition of HO-1 Attenuates HMP-Induced Hepatic Regeneration against Liver Injury in Rats.

We found better liver graft regeneration with hypothermic machine perfusion (HMP) compared with static cold storage (SCS) for the first time in our pilot study, but the underlying mechanisms are unknown. Upregulated heme oxygenase- (HO-) 1 expression has been reported to play a pivotal role in promoting hepatocyte proliferation. Here, we evaluated the novel role of HO-1 in liver graft protection by HMP. Rats with a heterozygous knockout of HO-1 (HO-1+/−) were generated and subjected to 3 h of SCS or HMP pre-half-size liver transplantation (HSLT) in vivo or 6 h of SCS or HMP in vitro; control rats were subjected to the same conditions (HO-1+/+). We found that HSLT induced significant elevation of the HO-1 protein level in the regenerated liver and that HO-1 haplodeficiency resulted in decreased proliferation post-HSLT. Compared with SCS, HMP induced significant elevation of the HO-1 protein level along with better liver recovery, both of which were reduced by HO-1 haplodeficiency. HO-1 haplodeficiency-induced decreased proliferation was responsible for the attenuated regenerative ability of HMP. Mechanistically, HO-1 haploinsufficiency resulted in suppression of hepatocyte growth factor (HGF)/Akt activity. Our results suggest that inhibition of HO-1 mitigates HMP-induced liver recovery effects related to proliferation, in part, by downregulating the HGF-Akt axis.

Dual-graft adult living donor liver transplantation with ABO-incompatible graft: short-term and long-term outcomes.

ABO-incompatible (ABOi) dual-graft (DG) adult living donor liver transplantation (ALDLT) is not commonly performed due to its inherently intricate surgical technique and immunological complexity. Therefore, data are lacking on the short- and long-term clinical outcomes of ABOi DG ALDLT. We performed a retrospective study by reviewing the medical records of patients who underwent ABOi DG ALDLT between 2008 and 2014. Additionally, computed tomography volumetric analysis was conducted to assess the graft regeneration rate. The mean age of a total of 28 recipients was 50.2±8.5years, and the mean model for end-stage liver disease score was 12.2±4.6. The 1-, 3-, and 5-year patient survival rate was 96.4% during the mean follow-up period of 57.0±22.4months. The 1-, 3-, and 5-year graft survival rate was 96.4%, 94.2%, and 92.0%, respectively, and no significant differences were observed between ABO-compatible (ABOc) and ABOi grafts (P=.145). The biliary complication rate showed no significant difference (P=.195) between ABOc and ABOi grafts. Regeneration rates of ABOi grafts were not significantly different from those of ABOc grafts. DG ALDLT with ABOi and ABOc graft combination seems to be a feasible option for expanding the donor pool without additional donor risks.

Significance of Portal Venous Velocity in Short-term Graft Function in Living Donor Liver Transplantation

BackgroundGraft regeneration and functional recovery after reperfusion of transplanted graft are very important for successful living donor liver transplantation (LDLT). The aim of this study was to evaluate the significance of postoperative portal venous velocity (PVV) in short-term recovery of graft function in LDLT. Patients and MethodsFrom February 2007 through December 2015, we performed 17 primary LDLTs, which were included in the present study. The patients ranged in age from 12 to 65 years (mean: 50 years), and 11 were female patients. Postoperatively, Doppler ultrasonography was performed daily to measure PVV (cm/s), and liver function parameters were measured daily. The change in PVV (ΔPVV) was defined as follows: ΔPVV = PVV on postoperative day (POD) 1 − PVV on POD 7. Maximal value of serum aspartate aminotransferase (ASTmax) and maximal value of serum alanine transaminase (ALTmax) at 24 hours after graft reperfusion were used as parameters of reperfusion injury. Correlation analyses were performed as follows: (1) correlation of ΔPVV and PVV on POD 1 (PVV-POD 1) with the values such as ASTmax, ALTmax, other liver function parameters on POD 7 and graft regeneration rate; (2) correlation of ASTmax and ALTmax with other liver function parameters on POD 7. ResultsΔPVV significantly correlated with the values of serum total bilirubin (P < .01), prothrombin time (P < .01), and platelet count (P < .05), and PVV-POD 1 significantly correlated with the values of serum total bilirubin (P < .05) and prothrombin time (P < .05). ConclusionΔPVV and PVV-POD 1 may be useful parameters of short-term functional recovery of the transplant liver in LDLT.

Postoperative changes in neutrophil-to-lymphocyte ratio and platelet count: A simple prognostic predictor for adult-to-adult living donor liver transplantation

The neutrophil-to-lymphocyte ratio (NLR) is a simple index that represents systemic inflammatory change. The number of platelets is also known to reflect both post-transplant graft regeneration and dysfunction. Thus, we aimed to investigate the usefulness of NLR and platelet number in predicting the clinical course after adult-to-adult living donor liver transplantation (AA-LDLT) in the acute postoperative period in recipients. Between January 1999 and December 2013, 61 patients underwent their first AA-LDLT at our institute. We retrospectively analyzed their clinical data, including NLR and number of platelets, until postoperative day 14, and evaluated their ability to predict prognosis after AA-LDLT. The optimal cutoff values of postoperative maximum NLR and maximum platelets to predict prognosis were 50 and 80×103/μL, respectively. The 1- and 5-year survival rates were 87.5% and 79.1% in the normal maximum NLR group, respectively, and 46.2% for both in the high maximum NLR group (p=0.0033). The 1- and 5-year survival rates, respectively, were 90.9% and 84.1% in the high maximum platelets group and 47.1% and 41.2% in the low maximum platelets group (p<0.0001). In multivariate analysis, maximum NLR≥50 and maximum platelets<80×103/μL were independently associated with 1-year mortality. A high NLR and a low platelet count during acute postoperative period might correlate with poor prognosis after AA-LDLT.

Autogenous bone harvesting from iliac crest and symphysis for implant reconstruction

Horizontal and vertical bone resorption may be seen after tooth loss in the maxilla and mandible. The deficient edentulous ridge may interfere with the insertion of implants of adequate length placed in the correct position and with the ideal inclination. The severe alveolar bone resorption or pneumatisation of the maxillary sinus makes it difficult to perform the conventional dental implantation procedure. Functional implant-supported oral rehabilitation is increasingly being used as a restoration strategy for fully and partially edentulous patients, whenever sufficient bone volume is available. Implant-supported restoration is possible even in severely resorbed jaws using a reconstruction technique with bone augmentation that includes vascularised or nonvascularised bone grafting and tissue regeneration techniques. Standard donor sites for free autogenous bone-graft techniques are: the chin or ramus mandible, the iliac crest, the tibia and the calvaria. Advantages of intraoral mandibular sources include easy access, low morbidity, short healing periods, minimal graft resorption, and maintenance of high bone density; side effects include possible postoperative sensory disturbances and discomfort. Calvaria and iliac crest donor areas are most commonly used in cases of extensive alveolar ridge augmentation. The iliac crest generally supplies large quantities of corticocancellous bone. In this report, we present autogenous bone graft harvesting of 48 patients (40 iliac anterior crest, 8 symphysis) for facial reconstructive surgery.

Predictive Role of Intraoperative Plasma Fibrinogen for Postoperative Portal Venous Flow in Living Donor Liver Transplantation.

BACKGROUND Previous studies have reported poor graft regeneration after living donor liver transplantation (LDLT) due to inappropriate portal venous flow (PVF). In this study, we investigated the perioperative factors affecting postoperative PVF after LDLT. MATERIAL AND METHODS The perioperative data of 366 LDLT patients were retrospectively reviewed. The average PVF on postoperative days 1, 3, and 5 was measured and dichotomized at a cut-off value for patient survival of 1,477 mL/min. Perioperative variables, including coagulation profiles, were compared between high and low postoperative PVF groups. The factors potentially significant (p<0.1) for a low postoperative PVF were evaluated in a univariate analysis, followed by the development of a predictive model for a low postoperative PVF. RESULTS A low post-LDLT PVF was determined in 113 patients (30.9%). The univariate analysis identified systemic hypertension, LDLT duration, average mean blood pressure, and insulin administration as the significantly related factors. Other significant factors were a plasma fibrinogen, at the anhepatic phase and 1 h after graft reperfusion, as well as the platelet count at the anhepatic phase. After multivariate adjustment, plasma fibrinogen 1 h after graft reperfusion against a recipient background of systemic hypertension was independently associated with a low mean postoperative PVF. CONCLUSIONS A low mean PVF during the early post-LDLT period was independently related to the plasma fibrinogen level 1 h after graft reperfusion, and to a history of systemic hypertension. Thus, the practice of aggressive supplementation of plasma fibrinogen during the immediate post-reperfusion period merits serious consideration.

Periodontal wound healing following reciprocal autologous root transplantation in class III furcation defects.

PurposeFurcation involvement in the molars is difficult to treat, and has been recognized as a risk factor for tooth loss. Although periodontal regenerative therapies, including guided tissue regeneration and various types of bone grafts, have been applied to furcation defects, the effects of these treatments are limited, especially in large class III furcation defects. The purpose of this pilot study was to investigate the effect of reciprocal autologous root transplantation on periodontal wound healing and regeneration in class III furcation defects in dogs.MethodsFurcation defects (7 mm wide and 6 mm high) were surgically created after root separation of the unilateral third and fourth premolars in 4 dogs. Eight furcation defects were randomized to receive either reciprocal autologous root transplantation (test) or no further treatment (control). In the test group, the mesial and distal roots were transplanted into the distal and mesial extraction sockets, respectively. The animals were sacrificed 10 weeks after surgery for histologic evaluation.ResultsThe healing pattern in the control group was characterized by extensive collapse of the flap and limited periodontal regeneration. New bone formation in the test group (3.56±0.57 mm) was significantly greater than in the control group (0.62±0.21 mm). Dense collagen fibers inserting into the residual cementum on the transplanted root surfaces were observed in the test group. Slight ankylosis was observed in 2 of the 4 specimens in the test group on the mesiodistal sides where the root-planed surfaces faced the existing bone. Root resorption (RR) was detected in both the control and test groups.ConclusionsWithin the limits of this study, it can be concluded that reciprocal autologous root transplantation was effective for bone regeneration in class III furcation defects in dogs. However, further studies are required to standardize the approach in order to prevent unwanted RR prior to clinical application.

Regeneration and Cell Recruitment in an Improved Heterotopic Auxiliary Partial Liver Transplantation Model in the Rat

Auxiliary partial liver transplantation (APLT) in humans is a therapeutic modality used especially to treat liver failure in children or congenital metabolic disease. Animal models of APLT have helped to explore therapeutic options. Though many groups have suggested improvements, standardizing the surgical procedure has been challenging. Additionally, the question of whether graft livers are reconstituted by recipient-derived cells after transplantation has been controversial. The aim of this study was to improve experimental APLT in rats and to assess cell recruitment in the liver grafts. To inhibit recipient liver regeneration and to promote graft regeneration, we treated recipients with retrorsine and added arterial anastomosis. Using green fluorescence protein transgenic rats as recipients, we examined liver resident cell recruitment within graft livers by immunofluorescence costaining. In the improved APLT model, we achieved well-regenerated grafts that could maintain regeneration for at least 4 weeks. Regarding the cell recruitment, there was no evidence of recipient-derived hepatocyte, cholangiocyte, or hepatic stellate cell recruitment into the graft. Macrophages/monocytes, however, were consistently recruited into the graft and increased over time, which might be related to inflammatory responses. Very few endothelial cells showed colocalization of markers. We have successfully established an improved rat APLT model with arterial anastomosis as a standard technique. Using this model, we have characterized cell recruitment into the regenerating grafts.

Synergistic Effects of Growth Factor, Bone Graft, and Resorbable Barrier Membrane in Management of Dehiscence and Fenestration of Dental Implants

ABSTRACT Aim The present study was primarily designed to evaluate the outcome of guided bone graft regeneration in peri-implant defects by combining recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and granules of beta-tricalcium phosphate (B-TCP) mounted by resorbable biomesh membrane. Secondary objective was to determine the value of resorbable barrier membrane to improve the efficacy of the growth factormediated regeneration. Materials and methods A randomized controlled study comprised 14 participants (8 males and 6 females, mean age 37 years, range 19—55 years), in which a total of 15 implants (10 in maxilla and 5 in the mandible) were placed. Fifteen implant sites were randomly divided by picking a code into three groups: Test group I (n = 5) ß-TCP + rhPDGF (0.3 mg/mL) + biomesh, test group II (n = 5) ß-TCP + rhPDGF, and control (n = 5) ß-TCP + biomesh. The experimental site was examined clinically for the gingival status and radiographically for the bone status. Results Statistically significant difference in preoperative and postoperative measurements was observed for test groups I and II in all the parameters except width; in contrast, there was no significant difference observed for the control group from baseline to 5 months postoperatively. On intergroup comparison, statistically significant difference was observed between test group I vs control group and test group II vs control group, but it was not significant between test groups I and II, which was further confirmed using global performance scale score. Conclusion It concluded that rhPDGF-BB and ß-TCP mounted by resorbable biomesh membrane played a synergistic role in the management of peri-implant defects. Clinical significance Bone regenerated using ß-TCP with rhPDGF-BB in the reversal of peri-implant defects. How to cite this article Arora R, Verma UP, Dixit J, Lal N. Synergistic Effects of Growth Factor, Bone Graft, and Resorbable Barrier Membrane in Management of Dehiscence and Fenestration of Dental Implants. World J Dent 2017;8(3):177-182.

Association Between Intraoperative Platelet Transfusion and Early Graft Regeneration in Living Donor Liver Transplantation.

To evaluate the association between anesthetic management before and after graft reperfusion and early graft regeneration in living donor liver transplantation (LDLT). Sufficient graft regeneration is essential for the success of LDLT. Diverse signals start to trigger liver regeneration immediately after graft reperfusion. Graft volume at 14 ± 2 days after LDLT was measured in 379 consecutive recipients using computed tomography images with 3-dimensional reconstruction. The association between anesthetic variables and the degree of graft regeneration for 2 weeks was analyzed using simple and multiple linear regressions. The anesthetic variables included hemodynamics, laboratory measurements, vasoactive drugs, and blood products transfusion. The degree of graft regeneration for 2 weeks was 52% in median and ranged from 5% to 123%. Platelet transfusion was identified as the sole independent anesthetic factor contributing to graft regeneration. Platelet concentrate transfusion of 1 to 6 units vs none was correlated with a 6.5% increase in graft regeneration (P = 0.012). Platelet concentrate transfusion of more than 6 units vs none was further correlated with an 18.4% increase in regeneration (P < 0.001). In the subgroup of recipients without intraoperative platelet transfusion, mean platelet count measured during the intraoperative reperfusion phase was positively associated with graft regeneration (P = 0.033). Graft regeneration after LDLT increased in relation to a graded increase in the amount of transfused platelets and higher postreperfusion platelet counts during surgery. These results offer additional evidence regarding the important role of platelets in initiating liver regeneration and, furthermore, the indications for and the benefits vs risks of platelet transfusion during LDLT.

Impact of Portal Hemodynamic Changes in Partial Liver Grafts on Short-Term Graft Regeneration in Living Donor Liver Transplantation.

Regeneration of partial liver grafts is critical for successful living donor liver transplantation (LDLT), especially in adult recipients. The purpose of this study was to investigate the intraoperative hemodynamic changes in partial liver grafts and characterize their potential impact on post-transplant liver regeneration in LDLT. We examined the portal venous flow (PVF) and hepatic arterial flow (HAF) to partial liver grafts by means of ultrasonic transit time flowmeter of donors immediately before graft retrieval and of the corresponding recipients after vascular reconstruction in 48 LDLT cases. We evaluated post-transplant liver regeneration according to the changes in graft liver volume between the time of transplantation and the 7th post-transplant day. There was a significant increase in PVF to the partial liver grafts in recipients (rPVF) compared with that in donors. In contrast, graft HAF in recipients significantly decreased compared with that in donors. The rPVF inversely correlated with graft weight (GW)-recipient body weight ratio (GRWR), whereas HAF volume showed no significant correlation. The rPVF/GW positively correlated with the rate of liver regeneration (GRR), which inversely correlated with GRWR. The rPVF/GW was significantly higher, and GRR tended to be larger in the small graft group than in the non-small graft group. Intraoperative portal hemodynamic changes in partial liver grafts strongly affect their post-transplant regeneration. In particular, in small liver grafts, an immediate and remarkable increase in graft PVF may contribute to rapid liver regeneration after LDLT if the increased PVF remains within a safe range.

Engineered acellular collagen scaffold for endogenous cell guidance, a novel approach in urethral regeneration.

The treatment of congenital malformations or injuries of the urethra using existing autologous tissues can be associated with post-operative complications. Using rat-tail collagen, we have engineered an acellular high-density collagen tube. These tubes were made of 2 layers and they could sustain greater burst pressures than the monolayered tubes. Although it remains a weak material this 2 layered tube could be sutured to the native urethra. In 20 male New Zealand white rabbits, 2cm long grafts were sutured in place after subtotal excision of the urethra. This long-term study was performed in Lausanne (Switzerland) and in Kuala Lumpur (Malaysia). No catheter was placed post-operatively. All rabbits survived the surgical implantation. The animals were evaluated at 1, 3, 6, and 9months by contrast voiding cysto-urethrography, histological examination and immunohistochemistry. Spontaneous re-population of urothelial and smooth muscle cells on all grafts was demonstrated. Cellular organization increased with time, however, 20% of both fistula and stenosis could be observed post-operatively. This off-the shelf scaffold with a promising urethral regeneration has a potential for clinical application. In this study we have tissue engineered a novel cell free tubular collagen based scaffold and used it as a urethral graft in a rabbit model. The novelty of our technique is that the tube can be sutured. Testing showed better burst pressures and the grafts could then be successfully implanted after a urethral excision. This long term study demonstrated excellent biocompatibility of the 2cm graft and gradual regeneration with time, challenging the current literature. Finally, the main impact is that we describe an off-the-shelf and cost-effective product with comparable surgical outcome to the cellular grafts.

Simultaneous Osteoperiosteal Autologous Iliac Crest Graft and Lateral Meniscus Allograft Transplantation for Osteochondral Lesion with Bony Defect and Lateral Discoid Meniscus Tear.

The optimal treatment for combined osteochondritis dissecans (OCD) with considerable bony defect of the lateral femoral condyle (LFC) and torn discoid lateral meniscus is unclear. We present a case of a 15-year-old female who was a gymnast and had a large OCD lesion in the LFC combined with deficiency of the lateral meniscus. The patient underwent the "one-step" technique of osteoperiosteal autologous iliac crest graft and lateral meniscus allograft transplantation after a failure of meniscectomy with repair at another hospital. Twenty-four months postoperatively, clinical results were significantly improved. Follow-up imaging tests and second-look arthroscopy showed well incorporated structured bone graft and fibrous cartilage regeneration as well as stabilized lateral meniscus allograft. She could return to her sport without any pain or swelling. This "one-step" surgical technique is worth considering as a joint salvage procedure for massive OCD lesions with torn discoid lateral meniscus.

Composite vascular grafts with high cell infiltration by co-electrospinning

There is an increasing demand for functional small-diameter vascular grafts (diameter<6mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation.

The effect of infliximab on bone healing in osteoporotic rats

Purpose: The aim of this study was to evaluate the effect of the infliximab on autogenous-mediated bone regeneration and resorption of autogenous graft in the ovariectomised rat model. Materials and methods: Forty rats underwent ovariectomy and 6 weeks later the animals were randomly assigned to four groups. Critical size defects were created in each rat calvarium. In the control group (C), the flap was closed without any further action. In the only infliximab group (In), the flap was closed without any further action. After the operation, intravenous infliximab was injected. In the autogenous graft group (Ag), autogenous bone was applied in to the defect. In autogenous graft + infliximab group (Ag+In), autogenous graft was placed on the defect. After the operation, intravenous infliximab was injected. The animals were sacrificed at 4 weeks. Bone formation was assessed by micro-computed tomography (micro-CT) scans and stereological analysis. Results: The mean new bone volume was the greatest in Ag+In group (1.76 ± 0.20), followed by the Ag group (1.51 ± 0.05) (statistically significant difference at P &lt;0.05). The lowest new bone was found in the control group (1.05 ± 0.09), however no difference was observed from the In group (1.14 ± 0.08) ( P &gt;0.05). Besides there was a statistically significant difference between the Ag+In group (1.00 ± 0.05) and Ag group (0.74 ± 0.04) in terms of the graft volume ( P &lt;0.05). Conclusion: This study, despite its limitations, showed that infliximab has a beneficial effect for prevent graft resorption and bone regeneration in osteoporotic rats.

Bacterial influence on consolidation of bone grafts in maxillary sinus elevation.

The aim of this study was to identify microorganisms present on the maxillary sinus floor at the moment of sinus elevation surgery and, using tomography, to investigate the repercussions these might have for regenerated bone 9months after the procedure. 174 patients (90 women and 84 men) with a mean age of 55.92years underwent 227 sinus elevations (120 left sinus, 107 right sinus). As the membrane was lifted, a sample of the maxillary sinus floor was collected with a cotton swab, and placed on a blood agar and chocolate agar culture to incubate for 48h at 37°C; the samples then underwent microbiological analysis. Orthopantomographs and computerized tomographs were made immediately after the sinus grafting and after 9months to measure the amount of remaining and regenerated bone in vertical and transversal direction. 18.1% of 227 cultures were bacteria-positive. 45% of the germs were of the Streptococcus genus, most of which belonged to the S.viridans group (61.1%). Patients presenting negative cultures had 5% more regenerated bone than patients with bacteria-positive cultures, which represents an additional 2.28 mmof vertical bone (with a confidence interval between 0.83mm and 3.73mm). Patients with bacteria-positive cultures obtained previously to the sinus grafting procedure have greater risk of bone height loss after 9months, which indicates that bacterial contamination may influence bone graft regeneration.

Effect of bone regeneration of CMC- and HA-based bone grafts in rabbits.

Event Abstract Back to Event Effect of bone regeneration of CMC- and HA-based bone grafts in rabbits. Soo Jin Son1, Seong Soo Kang2, Jun Sik Son3 and Seok Hwa Choi1* 1 Chungbuk National University, Veterinary Medical Center, Korea 2 Chonnam National University, Department of Veterinary Surgery, Korea 3 Korea Textile Development Institute, Fusion Textile Research, Korea Although autogenous bone is the most widely used graft material for bone defects, demineralized bone matrix materials are available as alternatives to autograft. This study was undertaken to assess the bone regeneration of bone graft substitutes in a rabbit segmental defect model. Comparison of bone regeneration between carboxymethylcellulose (CMC)-based bone source and hyaluronic acid (HA)-based bone source was the primary interest of the study, and to determine whether CMC-based demineralized or non-demineralized bone sources produce bone regeneration in a rabbit segmental defect model. Each 15-mm segmental defect in both left and right radiuses was created in 36 New Zealand White rabbits and filled either with HA-based demineralized cortical bone matrix (DBX), CMC-based demineralized cortical bone matrix (DB) or CMC-based demineralized cortical bone with cancellous bone (NDDB) in random order. Additional two rabbits as control were used to no treatment and they were used to radiographic examination only during 12 weeks post-operation. Four rabbits from each group were sacrificed at 4, 8, and 12 weeks post-implantation. The wound area was evaluated by radiology, micro-computerized tomography (CT) and histopathology. DBX has significantly lower radiopacity, bone volume fraction, and bone mineral density compared to DB and NDDB before implantation. However, there were no significant differences in bone healing capacity as revealed by similar bone healing score, bone volume fraction, bone mineral density, and residual bone area in radiographic assessment, micro-CT, and histological evaluation at 4, 8, and 12 weeks post-implantation. In conclusion, application of CMC-based and HA-based bone graft substitutes in a segmental bone defect rabbit model results in similar effects on bone regeneration.

Comparative accuracy of CT, dual-echo MRI and MR spectroscopy for preoperative liver fat quantification in living related liver donors.

Background:It is of significant importance to assess the extent of hepatic steatosis in living donor liver transplant (LDLT) surgery to ensure optimum graft regeneration as well as donor safety.Aim:To establish the accuracy of non-invasive imaging methods including computed tomography (CT), dual-echo in- and opposed-phase magnetic resonance imaging (MRI), and MR spectroscopy (MRS) for quantification of liver fat content (FC) in prospective LDLT donors with histopathology as reference standard.Settings and Design:This retrospective study was conducted at our institution on LDLT donors being assessed for biliary and vascular anatomy depiction by Magnetic Resonance Cholangiopancreatography (MRCP) and CT scan, respectively, between July 2013 and October 2014.Materials and Methods:Liver FC was measured in 73 donors by dual-echoT1 MRI and MRS. Of these, CT liver attenuation index (LAI) values were available in 62 patients.Statistical Analysis:CT and MRI FC were correlated with histopathological reference standard using Spearman correlation coefficient. Sensitivity, specificity, positive predictive value, negative predicative value, and positive and negative likelihood ratios with 95% confidence intervals were obtained.Results:CT LAI, dual-echo MRI, and MRS correlated well with the histopathology results (r = 0.713, 0.871, and 0.882, respectively). An accuracy of 95% and 96% was obtained for dual-echo MRI and MRS in FC estimation with their sensitivity being 97% and 94%, respectively. False-positive rate, positive predictive value (PPV), and negative predicative value (NPV) were 0.08, 0.92, and 0.97, respectively, for dual-echo MRI and 0.03, 0.97, and 0.95, respectively, for MRS. CT LAI method of fat estimation has a sensitivity, specificity, PPV, and NPV of 73%, 77.7%, 70.4%, and 80%, respectively.Conclusion:Dual-echo MRI, MRS, and CT LAI are accurate measures to quantify the degree of hepatic steatosis in LDLT donors, thus reducing the need for invasive liver biopsy and its associated complications. Dual-echo MRI and MRS results correlate better with histological results in the study, as compared to CT LAI method for fat quantification.

Outcomes of Tissue Expander Application for Scalp Reconstruction in Extensive Aplasia Cutis Congenita

Aplasia cutis congenita (ACC) is a rare congenital disorder. The purpose of this study was to present outcomes of tissue expander application for scalp reconstruction in extensive ACC. In this retrospective study, medical records were reviewed for six patients who underwent serial tissue expander application for scalp reconstruction in ACC between 2000 and 2015. Patient average age was 14.5 (range, 4-25 years). One of the six cases had frontal bone defect, the others had bone and soft tissue defect at the vertex. In the newborn period, all patients have been managed by split-thickness skin grafts without cranioplasty procedures. After grafting and calvarial regeneration, one (or more) sessions of tissue expanders and scalp flap applications were performed for alopecia and soft tissue correction. Radiologic and clinical examination was performed for complications and outcomes. Computerized tomography showed intact calvarium with patchy hyperostosis in all patients. The mean size of grafted areas was 69.5 cm(2) (range, 32-148.5 cm(2)). Minimal distal flap necrosis (6 × 1 cm) was observed in one patient. Serial scalp tissue expansion was performed with at least one session in a 1-year interval. One expander was extracted due to exposition and infection. No total flap losses and no calvarial defects were observed during follow-up (mean; 8.6 years). Clinical examination revealed acceptable cosmetic results in all patients. We advocate late expander scalp reconstruction for management of extensive ACC cases. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Hepatic Arterial Buffer Response Maintains the Homeostasis of Graft Hemodynamics in Patient Receiving Living Donor Liver Transplantation.

In living donor liver transplantation (LDLT), the hepatic hemodynamics plays important roles in graft regeneration, and the hepatic blood inflows are associated with graft size. However, the data of interplay between the hepatic arterial buffer response (HABR) and graft-to-recipient weight ratio (GRWR) in clinical LDLT are lacking. To identify the effect of the HABR on the hepatic hemodynamics and recovery of graft function and to evaluate the safe lower limit of the GRWR in carefully selected recipients. Portal venous and hepatic arterial blood flow was measured in recipients with ultrasonography, and the graft functional recovery, various complications, and survive states after LDLT were compared. In total, 246 consecutive patients underwent LDLT with right lobe grafts. In total, 26 had a GRWR < 0.7 % (A), 29 had a GRWR between 0.7 and 0.8 % (B), and 181 had a GRWR > 0.8 % (C). For small-for-size syndrome, there was no significant difference (P = 0.176). Graft survival rates at 1, 3, and 5 year were not different (P = 0.710). The portal vein flow and portal vein flow per 100 g graft weight peaks were significantly higher in the A. Hepatic arterial velocity and hepatic arterial flow decreased in all the three groups on postoperative day 1; however, the hepatic arterial flow per 100 g graft weight was close to healthy controls. HABR played important roles not only in the homeostasis of hepatic afferent blood supply but also in maintaining enough hepatic perfusion to the graft.