Ex vivo investigation of the effect of the transverse arytenoid ligament on abduction of the arytenoid cartilage when performing equine laryngoplasty.

Aims: To investigate the effect of the transverse arytenoid ligament (TAL) on abduction of the arytenoid cartilage when performing laryngoplasty. Methods: Modified prosthetic laryngoplasty was performed on right and left sides of 13 cadaver larynges. Increasing force was sequentially applied to the left arytenoid cartilage at 3 N intervals from 0-24 N, when the force on the right arytenoid cartilage was either 0 or 24 N, before and after TAL transection. Digital photographs of the rostral aspect of the larynx were used to determine the left arytenoid abduction angles for these given force combinations and results compared before and after TAL transection. Longitudinal and transverse sections of the TAL from seven other equine larynges were also examined histologically. Results: Increasing force on the left arytenoid cartilage from 0-24 N produced a progressive increase in the angle of the left arytenoid cartilage (p < 0.001) and increasing force on the right arytenoid cartilage from 0-24 N reduced the angle of the left arytenoid cartilage (p < 0.001). Following transection of the TAL the mean angle of the left arytenoid increased from 36.7 (95% CI = 30.5-42.8)° to 38.4 (95% CI = 32.3-44.5)°. Histological examination showed that the TAL was not a discrete ligament between the arytenoid cartilages but was formed by the convergence of the ligament and the left and right arytenoideus transversus muscles. Conclusions: Transection of the TAL in ex vivo equine larynges enabled greater abduction of the left arytenoid cartilage for a given force. These results indicate that TAL transection in conjunction with prosthetic laryngoplasty may have value, but the efficacy and safety of TAL transection under load in vivo, and in horses clinically affected with recurrent laryngeal neuropathy must be evaluated. Abbreviations: Fmax: Force needed to maximally abduct the left or right arytenoid; TAL: Transverse arytenoid ligament.

Are we underestimating the quality of aviremic hepatitis C-positive kidneys? Time to reconsider.

Kidney Donor Risk Index (KDRI) introduced in 2009 included hepatitis C serologic but not viremic status of the donors. With nucleic acid amplification testing (NAT) now being mandatory, further evaluation of these donors is possible. We conducted a retrospective matched case-control analysis of adult deceased donor kidney transplants performed between December 5, 2014 to December 31, 2016 with the KDRI score and hepatitis C virus antibody (HCV Ab) and NAT testing status obtained from the United Network for Organ Sharing database. The 205 aviremic HCV Ab+ NAT - kidney transplants were compared to KDRI matched control kidneys that were HCV Ab-NAT-. The aviremic HCV kidneys were recovered from donors who were significantly younger, more likely to be white, and less likely to have hypertension and diabetes. The majority of the recipients of the aviremic HCV kidneys when compared to matched controls were HCV positive: 90.2% vs 4.3%. The recipients were significantly older, were on dialysis for a shorter time, and were transplanted sooner. The graft survival of aviremic HCV kidneys was similar (P < .08). If the HCV status of the aviremic kidneys was assumed to be negative, 122 more kidneys could have been allocated to patients with estimated posttransplant survival <20. Seven kidneys would no longer have Kidney Donor Profile Index >85%. Further policies might consider these findings to appropriately allocate these kidneys.

A high plasma: red blood cell transfusion ratio during liver transplantation is associated with decreased blood utilization.

BACKGROUND: During massive transfusion, the volume ratio of administered plasma (PL Vol) to red blood cell (RBC Vol) appears to be associated with reduced blood utilization and improved survival. The aim of this study was to evaluate the optimal component ratio in the setting of liver transplantation. METHODS: This is a retrospective chart review of patients who underwent liver transplantation and received at least 500 ml of red blood cells from January 2013 through December 2015. Kernel smoothing analysis determined the proper component ratios to evaluate were a ≥0·85:1 ratio (high) to a ≤0·85:1 ratio (low). Two groups, plasma volume to RBC volume (PL Vol/RBC Vol) and plasma contained in the platelet units added to the plasma calculation [PL + PLT (platelet)] Vol/RBC Vol, were used to evaluate the component ratios. RESULTS: A total of 188 patients were included in the analysis. In the PL Vol/RBC Vol evaluation, a low ratio revealed that 1238 ml (977-1653 ml) (P < 0·0001) and 1178 ml (747-1178) (P < 0·0001) of RBC were used in excess compared to the high ratio, in the univariable and multivariable analysis, respectively. In the PL +PLT Vol/RBC Vol evaluation, a low ratio used 734 ml (193-1275) (P = 0·008) and 886 ml (431-1340) (P < 0·0001) of RBC in excess when compared to high ratio in the univariable and multivariable analysis, respectively. CONCLUSION: In patients undergoing liver transplantation, the transfusion of plasma to RBC ratio ≥0·85 was associated with decreased need of RBC transfusions.

A data-driven patient blood management strategy in liver transplantation.

BACKGROUND AND OBJECTIVES: Blood utilization during liver transplant has decreased, but remains highly variable due to many complex surgical and physiologic factors. Previous models attempted to predict utilization using preoperative variables to stratify cases into two usage groups, usually using entire blood units for measurement. We sought to develop a practical predictive model using specific transfusion volumes (in ml) to develop a data-driven patient blood management strategy. MATERIALS AND METHODS: This is a retrospective evaluation of primary liver transplants at a single institution from 2013 to 2015. Multivariable analysis of preoperative recipient and donor factors was used to develop a model predictive of intraoperative red-blood-cell (pRBC) use. RESULTS: Of 256 adult liver transplants, 207 patients had complete transfusion volume data for analysis. The median intraoperative allogeneic pRBC transfusion volume was 1250 ml, and the average was 1563 ± 1543 ml. Preoperative haemoglobin, spontaneous bacterial peritonitis, preoperative haemodialysis and preoperative international normalized ratio together yielded the strongest model predicting pRBC usage. When it predicted <1250 ml of pRBCs, all cases with 0 ml transfused were captured and only 8·6% of the time >1250 ml were used. This prediction had a sensitivity of 0·91 and a specificity of 0·89. If predicted usage was >2000 ml, 75% of the time blood loss exceeded 2000 ml. CONCLUSION: Patients likely to require low or high pRBC transfusion volumes were identified with excellent accuracy using this predictive model at our institution. This model may help predict bleeding risk for each patient and facilitate optimized blood ordering.

Utilization of Organs From Donors According to Hepatitis C Antibody and Nucleic Acid Testing Status: Time for Change.

Previous studies have grouped all donors positive for hepatitis C virus (HCV) antibody (Ab). Only recently has donor HCV nucleic acid testing (NAT) become routine, and the impact of Ab and NAT status on organ utilization is unknown. Using the United Network for Organ Sharing database, we identified 9290 donors from 2015 to 2016 for whom both HCV Ab and NAT data were available and compared organ utilization by HCV status. Overall, 93.8% of donors were Ab negative and NAT negative (Ab-NAT-), 0.15% were Ab negative and NAT positive, 1.8% were Ab positive and NAT negative (Ab+NAT-), and 4.2% were both Ab and NAT positive (Ab+NAT+). Ab-NAT- donors donated at the highest rate for all organs except livers, of which Ab+NAT- donors donated at a higher rate (81.2% vs 73.2%, p = 0.03). Livers were discarded for reasons related to abnormal biopsies in Ab+NAT+ donors, whereas kidneys from Ab- or NAT-positive donors were discarded for reasons related to HCV status. Using a propensity score-matched model, we estimated that using Ab+NAT- donors at the same rate as Ab-NAT- donors could result in 48 more kidney donors, 37 more heart donors, and 15 more lung donors annually. We urge the use of HCV Ab+NAT- donors for appropriately selected and consenting recipients.

Surface origin of high conductivities in undoped In2O3 thin films.

The microscopic cause of conductivity in transparent conducting oxides like ZnO, In{2}O{3}, and SnO{2} is generally considered to be a point defect mechanism in the bulk, involving intrinsic lattice defects, extrinsic dopants, or unintentional impurities like hydrogen. We confirm here that the defect theory for O-vacancies can quantitatively account for the rather moderate conductivity and off-stoichiometry observed in bulk In{2}O{3} samples under high-temperature equilibrium conditions. However, nominally undoped thin-films of In{2}O{3} can exhibit surprisingly high conductivities exceeding by 4-5 orders of magnitude that of bulk samples under identical conditions (temperature and O{2} partial pressure). Employing surface calculations and thickness-dependent Hall measurements, we demonstrate that surface donors rather than bulk defects dominate the conductivity of In{2}O{3} thin films.

Optimizing Risk Assessment In Simultaneous Liver and Kidney Transplant: Donor and Recipient Factors Associated With Improved Outcome.

Standardization in allocation of kidneys for transplant simultaneous with livers and the creation of a "safety net" for kidney transplant after liver transplant alone (LTA) was designed to encourage clinicians to list patients for LTA when the likelihood of renal recovery and the necessity of simultaneous liver and kidney (SLK) transplant were unclear. We analyzed the United Network for Organ Sharing database of SLK recipients starting January 1, 2015. Organs from one deceased donor were used in each individual case. Univariate analysis was used to analyze recipient and donor characteristics against patient and graft survival of at least 1 year. Cox regression was employed for multivariable analysis controlling for donor risk index variables. SLK recipients who failed to achieve 1 year of post-transplant survival were more likely to be older, have higher model for end-stage liver disease scores, have diabetes, have received dialysis within one week of transplant, and required intensive care unit admission at transplantation. Patients who failed to survive for at least 1 year after SLK were more likely to have received organs from donors who were older with a higher kidney donor profile index. Using national data we identified SLK donor and recipient characteristics associated with poor post-transplant outcome. Clinicians involved in the decision to list patients with liver failure for LTA or SLK may use these associations to help guide decision making.

Risk stratification of kidneys from donation after cardiac death donors and the utility of machine perfusion.

There has been a dramatic increase in the utilization of kidneys from donors after cardiac death (DCD). While these organs represent an opportunity to expand the donor pool, the assessment of risk and optimal perioperative management remains unclear. Our primary aim was to identify risk factors for objective outcomes, and secondarily, we sought to determine what impact pulsatile machine perfusion (PMP) had on these outcomes. From 1993 to November 2008, 6057 DCD kidney transplants were reported to the Organ Procurement and Transplantation Network database, with complete endpoints for delayed graft function (DGF) and graft survival (GS). Risk factors were identified using a multivariable regression analysis adjusted for recipient factors. Age (50 yr) [OR 1.81, p < 0.0001] and cold ischemia time (CIT) (>30 h) [OR 3.22, p < 0.0001] were the strongest predictors of DGF. The use of PMP decreased the incidence of DGF only when donor age was >60 yr and improved long-term graft survival when donor age was >50 yr. Donor warm ischemia time >20 min was also found to correlate with increased DGF. While the incidence of DGF in DCD kidneys is significantly higher, the only factors the transplant surgeon can control are CIT and the use of PMP. The data suggest that the use of PMP in DCD kidneys <50 yr old provides little clinical benefit and may increase CIT.

Bacterial culture of septic synovial structures of horses: does a positive bacterial culture influence prognosis?

REASONS FOR PERFORMING STUDY: The influence of synovial fluid culture on short- and long-term prognosis of cases with septic synovitis requires study. HYPOTHESES: Horses with a positive bacterial culture from septic synovial fluid are less likely to survive or return to successful athletic function than those with a negative bacterial culture from septic synovial fluid. METHODS: Records of mature horses presented to 2 equine referral hospitals for investigation of suspected septic synovitis were examined. Horses (n=206) were included in the study if synovial fluid was submitted for full laboratory examination, including bacterial culture. A diagnosis of septic synovitis was based on a nucleated cell count>30x10(9) cells/l or>90% neutrophils and other clinical, cytological and bacteriological parameters. Long-term follow-up was obtained by telephone questionnaire. Univariate analysis, using the Fisher's exact test, was used for all outcomes. RESULTS: Fourteen (20.9%) of 67 horses with a positive bacterial culture from synovial fluid were subjected to euthanasia because of persistent synovial sepsis compared to 2 (1.44%) of 139 with negative bacterial cultures (P<0.001). Overall survival and successful long-term return to function in horses with a positive bacterial culture was 50% (24/48 horses) compared to 70.5% (74/105) in culture negative horses (P=0.01). In horses that survived to be discharged, successful long-term return to function was not significantly different between culture positive and culture negative groups. Growth of Staphylococcus aureus from synovial fluid did not affect short-term survival to discharge from the hospital compared to other positive bacterial culture; however, successful long-term return to function was only 30.4% (4/13) in horses from which S. aureus was cultured compared to 73.9% (17/23) of horses in which other bacteria were cultured (P=0.015). CONCLUSIONS AND POTENTIAL CLINICAL RELEVANCE: Horses with a positive bacterial culture from a septic synovitis have a poorer prognosis for survival to discharge from hospital and overall long-term return to function than horses that yielded no bacterial growth. When S. aureus was cultured, the long-term prognosis was poorer.

Histopathology and computed tomography of age-associated degeneration of the equine temporohyoid joint.

REASONS FOR PERFORMING STUDY: The aetiology of temporohyoid osteoarthropathy (THO) is unknown; both primary infectious and degenerative causes have been suggested. HYPOTHESIS: There is a significant association between increasing age and severity of temporohyoid joint degeneration. To examine the histopathology of the temporohyoid articulation in aged horses and to compare the appearance of the joint with computed tomography (CT) and peripheral quantitative CT (pQCT). METHODS: pQCT scans of the temporohyoid articulations were obtained bilaterally from 31 horses (range age 1-44 years) post mortem and images were graded by 2 blinded observers on 2 occasions for the presence of osteophytes, irregularity of the joint surface and mineralisation. Eight heads had been examined previously by CT, with the images similarly graded for the shape and density of the proximal stylohyoid bones, bone proliferation surrounding the joint, mineralisation of the tympanohyoid cartilage and the relationship of the petrous temporal bone to the stylohyoid bone. Sixteen temporohyoid joints were then evaluated histologically. RESULTS: There was significant association between the mean pQCT degeneration score and age (rho = 0.75; P<0.0001), between the pQCT and CT score (rho = 0.63; P = 0.01) and between the degenerative changes identified within each temporohyoid joint within each horse (rho = 0.81; P<0.0001). Age-associated changes included the development of a club shape by the proximal stylohyoid bone, rounding of the synostosis with the petrous temporal bone and extension of osteophytes from the petrous temporal bone to envelope the stylohyoid head and bridge the joint. In no horse was there any evidence of osteomyelitis within the petrous temporal bone, stylohyoid bone or tympanohyoid cartilage. CONCLUSIONS: This study provides evidence that age is associated with increasing severity of degenerative changes in the equine temporohyoid joint and that similar changes are commonly found bilaterally. POTENTIAL RELEVANCE: The changes identified appear similar, albeit milder to the changes reported in horses with THO, suggesting that degenerative, rather than infectious causes may underlie the aetiology of THO. Future work should be directed at examining the histopathology of clinical THO cases.

D-MELD, a simple predictor of post liver transplant mortality for optimization of donor/recipient matching.

Numerous donor and recipient risk factors interact to influence the probability of survival after liver transplantation. We developed a statistic, D-MELD, the product of donor age and preoperative MELD, calculated from laboratory values. Using the UNOS STAR national transplant data base, we analyzed survival for first liver transplant recipients with chronic liver failure from deceased after brain death donors. Preoperative D-MELD score effectively stratified posttransplant survival. Using a cutoff D-MELD score of 1600, we defined a subgroup of donor-recipient matches with significantly poorer short- and long-term outcomes as measured by survival and length of stay (LOS). Avoidance of D-MELD scores above 1600 improved results for subgroups of high-risk patients with donor age >/=60 and those with preoperative MELD >/=30. D-MELD >/=1600 accurately predicted worse outcome in recipients with and without hepatitis C. There is significant regional variation in average D-MELD scores at transplant, however, regions with larger numbers of high D-MELD matches do not have higher survival rates. D-MELD is a simple, highly predictive tool for estimating outcomes after liver transplantation. This statistic could assist surgeons and their patients in making organ acceptance decisions. Applying D-MELD to liver allocation could eliminate many donor/recipient matches likely to have inferior outcome.

Two- and three-dimensional computed tomographic anatomy of the enamel, infundibulae and pulp of 126 equine cheek teeth. Part 1: Findings in teeth without macroscopic occlusal or computed tomographic lesions.

REASONS FOR PERFORMING STUDY: Dental disorders are of major clinical importance in equine practice; however, the knowledge of normal dental anatomy, especially that of the pulp remains incomplete. Computed tomography (CT) is being used increasingly in the diagnosis of dental disease, although the normal 2- (2D) and 3-dimensional (3D) CT anatomy has not yet been fully described. OBJECTIVE: To describe the 2D and 3D CT appearance of the enamel, infundibulae and pulp of normal equine cheek teeth. METHODS: One-hundred-and-twenty-six cadaveric cheek teeth with eruption ages of 0.5-19 years were evaluated; CT scans of each tooth were performed after occlusal surface examination with a dental probe. Three-dimensional reconstructions of the enamel, infundibulae and pulp were created from the CT scans using greyscale thresholding and subsequent polynomial meshing. Each tooth was sectioned coronally or axially into serial slices using a band saw and the sections compared to the corresponding CT images. RESULTS: The CT reconstructions enabled the systematic description of the pulpar anatomy of the mandibular and maxillary cheek teeth in 3D, which has not been described in detail previously. The number of interpulpar communications between pulp horns and the pulpar volume of each tooth was shown to decrease with increasing age. The interpulpar communications of the maxillary cheek teeth were found to be of greater complexity and variety in comparison to their mandibular counterparts. Mandibular and maxillary cheek teeth showed different, but consistent patterns in their pulpar and enamel morphology. CONCLUSIONS AND POTENTIAL RELEVANCE: The detailed description of the normal 2D and 3D CT appearance of equine cheek teeth provides a reference basis for the diagnosis of dental disease with CT. Additionally, in depth knowledge of the pulpar anatomy of the equine cheek teeth is an essential prerequisite if endodontic therapy is to develop further in the future.

Two- and three-dimensional computed tomographic anatomy of the enamel, infundibulae and pulp of 126 equine cheek teeth. Part 2: Findings in teeth with macroscopic occlusal or computed tomographic lesions.

REASONS FOR PERFORMING STUDY: Dental disease often presents a diagnostic challenge in the horse. Computed tomography (CT) is increasingly used in the evaluation of head related disease in the horse, but the CT appearance of the most common dental diseases of horses has not yet been fully described. OBJECTIVE: To describe the CT appearance of the peripheral enamel, pulp, infundibular enamel and cement in equine cheek teeth with macroscopic occlusal or CT lesions. METHODS: In this study, 126 cadaveric cheek teeth with eruption ages of between 05 and 19 years were evaluated for lesions of their infundibulae, pulp and enamel using occlusal surface morphology, 2- (2D) and 3-dimensional (3D) CT and anatomical sectioning. Variations in teeth with no macroscopic lesions have been described in a previous study. The infundibular lesions were categorised further into one of 6 classifications. RESULTS: Infundibular lesions were identified on CT in 90% (115/128) of infundibulae. Of these, 65% (83/128) had infundibular lesions on occlusal surface examination. The extent of infundibular lesions observed varied with age group. All infundibulae over 6 years post eruption had detectable lesions. Peripheral enamel hypoplasia and enamel prolapses, were observed in 10% (12/126) and 1.6% (2/126) of teeth, respectively. The CT appearance of teeth with pulp infections was seen to vary with differing pathologies. CONCLUSIONS AND POTENTIAL RELEVANCE: The high prevalence of infundibular lesions should encourage consideration of their clinical significance, in addition to the role of infundibulae in dental disease of the horse. Two-dimensional and 3D CT proved to be highly valuable imaging modalities for dental disease, enabling lesions within the enamel, infundibulae and pulp of equine cheek teeth to be easily detected. The results of this study will facilitate the use of 2D and 3D CT as clinical diagnostic tools for dental disease and aid in the selection of the most appropriate treatment protocol.

Variability of resting endoscopic grading for assessment of recurrent laryngeal neuropathy in horses.

REASONS FOR PERFORMING STUDY: The extent to which variability affects endoscopic grading of arytenoid cartilage movement is uncertain. OBJECTIVE: To determine the observer and within horse variability of grading arytenoid cartilage movement in horses during resting endoscopic examination, using a 7-grade system. METHODS: Endoscopic recordings of the upper respiratory tract made at rest in 270 draught horses were reviewed independently by 2 veterinarians to assess interobserver variability when scoring horses' laryngeal function with a 7-grade system. Grading was repeated by both examiners in 80 randomly selected recordings in order to assess intraobserver variability. In 120 horses, endoscopy was repeated after 24-48 h, with videos graded by both veterinarians to assess intrahorse variability. RESULTS: The mean weighted kappa statistic for concordance within examiners was 0.867, with a mean intraobserver agreement of 763%. The weighted kappa statistic for concordance between the 2 examiners was 0.765, with an interobserver agreement of 63.1%. Of the horses receiving 2 endoscopic examinations, the same grade was assigned to 57.1% of horses at the second examination, when effects resulting from interobserver variability were removed. The mean weighted kappa statistic for concordance between the grade assigned at first vs. second examinations was 0.588, indicating only moderate agreement. CONCLUSIONS AND POTENTIAL RELEVANCE: Intra- and interobserver reliability of resting endoscopic grading of arytenoid cartilage movement using a 7-grade system was high when examinations were conducted by experienced veterinarians. However, there was moderate daily intrahorse variability, suggesting that results of resting endoscopic examinations performed on a single day should be interpreted with caution.

Effect of left-sided valvular regurgitation on mortality and causes of death among a population of middle-aged and older horses.

The effect of left-sided valvular regurgitation (LSVR) on the mortality of middle-aged and older horses was investigated in a prospective cohort study involving 19 yards and 1153 horses. The horses were examined to determine whether they had a cardiac murmur and its type, and their age, sex, breed type and occupation were recorded. They were followed up at intervals of two years by postal questionnaire, and after four years information on 773 horses was available. There was no significant difference in the mortality of the horses with and without LSVR, but small horses had a significantly higher risk of having LSVR than small ponies (odds ratio [OR] 2.33), and older horses were slightly more likely to have LSVR than young horses (OR 1.07). Twenty-nine per cent of the deaths reported by the owners were due to orthopaedic problems, 23.3 per cent to gastrointestinal problems, and only 7.9 per cent to cardiovascular problems. Orthopaedic problems were the main cause of death in the horses, and gastrointestinal problems were the main cause of death in the ponies.

New insights into mechanisms of spontaneous liver transplant tolerance: the role of Foxp3-expressing CD25+CD4+ regulatory T cells.

Liver allografts in mice are accepted across MHC barriers without requirement for immunosuppressive therapy. The mechanisms underlying this phenomenon remain largely undefined. In this study, we investigated the role of Foxp3-expressing CD25(+)CD4(+) regulatory T cells (Treg) in the induction of murine liver transplant tolerance. Foxp3(+)CD25(+)CD4(+) T cells were increased in liver grafts and recipient spleens from day 5 to day 100 posttransplantation, associated with enhanced CTLA4 and TGF-beta expression and IL-4 production. Depletion of recipient CD25(+)CD4(+) T cells using anti-CD25 mAb (250 microg/day) induced acute liver allograft rejection. This was associated with a decreased ratio of Foxp3(+) Treg: T effector cells, decreased IL-4 and elevated IL-10 and IL-2 production by graft-infiltrating T cells, and reduced apoptotic activity of graft-infiltrating CD4(+) and CD8(+) T cells in anti-CD25-mAb-treated recipients. Thus, the data suggest that Foxp3(+)CD25(+)CD4(+)Treg are involved in spontaneous acceptance of liver allografts in mice. The ratio of Treg to T effector cells appears to determine liver transplant outcome. CTLA4, IL-4, TGF-beta and apoptosis of graft-infiltrating T cells are also associated with liver transplant tolerance and may contribute, at least in part, to the mechanisms of Treg-mediated immune regulation in this model.

Modified first or second cervical nerve transplantation technique for the treatment of recurrent laryngeal neuropathy in horses.

BACKGROUND: In horses, the only established method for reinnervation of the larynx is the nerve-muscle pedicle implantation, whereas in human medicine, direct nerve implantation is a standard surgical technique for selective laryngeal reinnervation in human patients suffering from bilateral vocal fold paralysis. OBJECTIVES: (1) To describe a modified first or second cervical nerve transplantation technique for the treatment of recurrent laryngeal neuropathy (RLN) in horses and (2) evaluate the outcomes of reinnervation using direct nerve needle-stimulation of the first cervical nerve and exercising endoscopy before and after surgery. STUDY DESIGN: Case series. METHODS: Nerve transplantation surgery, in which the first or second cervical nerve is tunnelled through the atrophied left cricoarytenoideus dorsalis muscle, was performed in combination with ipsilateral laser ventriculocordectomy. Ultrasound-guided stimulation of the first cervical nerve at the level of the alar foramen was used to confirm successful reinnervation post-operatively. Exercising endoscopy was performed before and after surgery. The exercising RLN grade of the left arytenoid was blindly determined at the highest stride frequency for each examination. RESULTS: Surgery was performed in 17 client-owned animals with RLN. Reinnervation was confirmed by nerve stimulation and subsequent arytenoid abduction observed in 11 out of 12 cases between 4 and 12 months post-operatively. Fourteen horses had exercising endoscopy before and after surgery. Nine horses had an improved exercising RLN grade, four horses had the same exercising grade and one horse had a worse exercising grade after surgery. MAIN LIMITATIONS: A sham-operated control group was not included and follow-up beyond 12 months and objective performance data were not obtained. CONCLUSIONS: The modified first or second cervical nerve transplantation technique, using tunnelling and direct implantation of the donor nerve into the cricoarytenoideus dorsalis muscle, resulted in reinnervation in 11 out of 12 cases and improved exercising grade in 9 out of 14 horses within 12 months after surgery.

Unintended Consequences in Use of Increased Risk Donor Kidneys in the New Kidney Allocation Era.

BACKGROUND: The new kidney allocation system (KAS) intends to allocate the top 20% of kidneys to younger recipients with longer life expectancy. We hypothesized that the new KAS would lead to greater allocation of Public Health Service (PHS) increased-risk donor organs to younger recipients. METHODS: Analyses of the Organ Procurement and Transplantation Network data of patients who underwent primary deceased kidney transplantation were performed in pre- and post-KAS periods. RESULTS: The allocation of PHS increased-risk kidney allografts in various age groups changed significantly after implementation of the new KAS, with an increased proportion of younger individuals receiving increased-risk kidneys (7% vs 10% in age group 20-29 y and 13% vs 18% in age group 30-39 y before and after KAS, respectively; P < .0001). This trend was reversed in recipients 50-59 years old, with 31% in the pre-KAS period compared with 26% after KAS (P < .0001). CONCLUSIONS: The new KAS resulted in a substantial increase in allocation of PHS increased-risk kidneys to candidates in younger age groups. Because increased-risk kidneys are generally underutilized, future efforts to optimize the utilization of these organs should target younger recipients and their providers.

The role of Foxp3+ regulatory T cells in liver transplant tolerance.

The liver has long been considered a tolerogenic organ that favors the induction of peripheral tolerance. The mechanisms underlying liver tolerogenicity remain largely undefined. In this study, we characterized Foxp3-expressing CD4+ CD25+ regulatory T cells (Treg) in liver allograft recipients and examined the role of Treg in inherent liver tolerogenicity by employing the mouse spontaneous liver transplant tolerance model. Orthotopic liver transplantation was performed from C57BL/10 (H2b) to C3H/HeJ (H2k) mice. The percentage of CD4+ CD25+ Treg was expanded in the liver grafts and recipient spleens from day 5 up to day 100 posttransplantation, associated with high intracellular Foxp3 and CTLA4 expression. Immunohistochemistry further demonstrated significant numbers of Foxp3+ cells in the liver grafts and recipient spleens and increased transforming growth factor beta expression in the recipient spleens throughout the time courses. Adoptive transfer of spleen cells from the long-term liver allograft survivors significantly prolonged donor heart graft survival. Depletion of recipient CD4+ CD25+ Treg using anti-CD25 monoclonal antibody (250 microg/d) induced acute liver allograft rejection, associated with elevated anti-donor T-cell proliferative responses, CTL and natural killer activities, enhanced interleukin (IL)-2, interferon-gamma, IL-10, and decreased IL-4 production, and decreased T-cell apoptotic activity in anti-CD25-treated recipients. Moreover, CTLA4 blockade by anti-CTLA4 monoclonal antibody administration exacerbated liver graft rejection when combined with anti-CD25 monoclonal antibody. Thus, Foxp3+ CD4+ CD25+ Treg appear to underpin spontaneous acceptance of major histocompatability complex- mismatched liver allografts in mice. CTLA4, IL-4, and apoptosis of alloreactive T cells appear to contribute to the function of Treg and regulation of graft outcome.

Anti-CD25 mAb administration prevents spontaneous liver transplant tolerance.

Liver allografts are accepted spontaneously in all mouse strain combinations without immunosuppressive therapy. The mechanisms underlying this phenomenon remain largely undefined. In this study, we examined the effect of CD4+ CD25+ T regulatory cells (Treg) on the induction of mouse liver transplant tolerance. Orthotopic liver transplantation was performed from B10 (H2b) to C3H (H2k) mice. Depleting rat anti-mouse CD25 mAb (PC61) was given to the donors or recipients (250 microg/d IP) pretransplant or to the recipients postoperatively. At day 5 posttransplantation, both effector T cells (mainly CD8) and CD4+ CD25+ Treg were increased in the liver allografts and host spleens compared to naïve mice. Anti-CD25 mAb administration, either pretransplantation or posttransplantation, reduced the ratio of CD4+ CD25+ Treg to the CD3 T cells of liver grafts and recipient spleens and induced liver allograft acute rejection compared to IgG treatment. Anti-CD25 mAb administration elevated anti-donor T-cell proliferative responses and CTL and NK activities of graft infiltrates and host splenocytes; reduced CTLA4, Foxp3, and IDO mRNA levels; increased IL-10 and IFN-gamma; and decreased IL-4 mRNA levels in the livers or host spleens. The number of apoptotic T cells was reduced significantly in the liver grafts and treated host spleens. Therefore, anti-CD25 mAb administration changed the balance of CD4+ CD25+ Treg to activated T cells of liver graft recipients, preventing liver transplant tolerance. This was associated with enhanced anti-donor immune reactivity, downregulated Treg gene expression, and reduced T cell apoptosis in the grafts and host spleens.