Demographic History of the Genus Pan Inferred from Whole Mitochondrial Genome Reconstructions

The genus Pan is the closest genus to our own and it includes two species, Pan paniscus (bonobos) and Pan troglodytes (chimpanzees). The later is constituted by four subspecies, all highly endangered. The study of the Pan genera has been incessantly complicated by the intricate relationship among subspecies and the statistical limitations imposed by the reduced number of samples or genomic markers analyzed. Here, we present a new method to reconstruct complete mitochondrial genomes (mitogenomes) from whole genome shotgun (WGS) datasets, mtArchitect, showing that its reconstructions are highly accurate and consistent with long-range PCR mitogenomes. We used this approach to build the mitochondrial genomes of 20 newly sequenced samples which, together with available genomes, allowed us to analyze the hitherto most complete Pan mitochondrial genome dataset including 156 chimpanzee and 44 bonobo individuals, with a proportional contribution from all chimpanzee subspecies. We estimated the separation time between chimpanzees and bonobos around 1.15 million years ago (Mya) [0.81-1.49]. Further, we found that under the most probable genealogical model the two clades of chimpanzees, Western + Nigeria-Cameroon and Central + Eastern, separated at 0.59 Mya [0.41-0.78] with further internal separations at 0.32 Mya [0.22-0.43] and 0.16 Mya [0.17-0.34], respectively. Finally, for a subset of our samples, we compared nuclear versus mitochondrial genomes and we found that chimpanzee subspecies have different patterns of nuclear and mitochondrial diversity, which could be a result of either processes affecting the mitochondrial genome, such as hitchhiking or background selection, or a result of population dynamics.

Health-related quality of life in pediatric intestinal transplantation

To determine HRQOL after pediatric intestinal transplantation. Thirty-four IT survivors from 1999 to 2012 were asked to complete age-specific HRQOL non-disease-specific questionnaires: TAPQOL (0-4 yr), KINDL-R (5-7 yr; 8-12 yr; 13-17 yr), and SF-36v2 (>18 yr), all validated with Spanish population. Primary caregiver completed a SF-36 questionnaire and CBI. Thirty-one participants were included. Median age was 10.2 yr (1-29) and time after transplant 4.4 yr (0-13). Overall patient scores were 78.2 ± 10.6 (n = 8), 83.3 ± 9.7 (n = 6), 72.2 ± 9.21 (n = 6), 80.5 ± 12.4 (n = 7), and 82.2 ± 12.4 (n = 4) for each age group. Highest scores were obtained for vitality (group I), self-esteem (group IV), and physical and social functioning and emotions (group V). Lowest scores were obtained in appetite and behavior (I), family and school (III), and chronic disease perception (III, IV). No significant differences were found between caregivers and their children. CBI showed stress in 52%. SF-36 for caregivers was lower than general population. No significant differences were found depending on relevant clinical and sociodemographic data. HRQOL was acceptable and improved with age and time since transplantation. Parents had a slighter own QOL and worse perception of health than their children. When successful, intestinal transplantation allows a normal life in most patients and can be offered as an attractive option.

Preservation of the native spleen in multivisceral transplantation

The native spleen is usually removed in patients undergoing MTV. The consequential asplenic state is associated with a high risk of sepsis, especially in immunosuppressed children. In contrast, the inclusion of an allogeneic spleen in multivisceral grafts has been associated with a high incidence of GVHD. We propose an alternative technique for patients undergoing MTV, consisting of the preservation of the native spleen. This approach avoids the additional risk of infection that characterizes the asplenic state without the detrimental side effects of the allogeneic spleen.

Liver transplantation in children with cystic fibrosis: experience in our centre and preliminary results with a combined en bloc liver-pancreas graft

AIM OF THE STUDY

Cystic fibrosis (CF) is a multisystemic disease, with some patients developing end-stage liver disease (ESLD), requiring liver transplantation (LT). These children usually present with severe mutations of the CFTR gene. Almost 100% of patients with severe mutations develop exocrine pancreatic insufficiency, leading later to endocrine insufficiency. Immunosuppression accelerates the development of insulin-dependent diabetes (IDD) in transplanted children with CF. Our aims were: (1) to analyze our experience with CF-related ESLD children who received LT, and the relationship to the development of IDD; (2) to report our preliminary results with en bloc liver-pancreas transplantation (CLPT).

METHODS

9 children (6M/3F) with CF and ESLD underwent LT between 1993 and 2010; median age and weight were 12.3 years (range: 5.4-17.0) and 36.7 kg (range: 14.2-58.5), respectively. 4 patients received a whole graft, 4 had reduced grafts (1 split) and 1 underwent CLPT. Immunosuppression followed the protocols at the time of transplantation.

RESULTS

Liver function was restored in all patients and none of them needed re-transplantation. Median follow-up was 105 months (range: 4-206). 1 child died of respiratory failure at 23 months after transplantation while awaiting pulmonary transplantation. Survival (Kaplan-Meier) at 105 months was 87.5%. 4 children already had IDD before transplantation and 3 developed diabetes immediately after transplantation. 2 had not developed IDD at the end of the study: the youngest at the time of LT (5.4 years, follow-up 7.1 years) and the girl who had had CLPT and who recovered normal exocrine and endocrine pancreatic function after transplantation.

CONCLUSIONS

LT is a realistic option to treat CF-related ESLD children. IDD is common in these patients. En bloc liver-pancreas transplantation is an appealing option, since it simultaneously restores exocrine function and prevents IDD. This procedure has clear technical advantages over simultaneous isolated liver and pancreas transplantation.

Variant techniques for liver transplantation in pediatric programs

INTRODUCTION

Several variant techniques have been developed as alternatives to whole liver transplantation to improve size matching, timing, or simply to increase the pool of donors. The aim of this study was to assess the requirements of these techniques and their outcomes in a pediatric transplant program.

PATIENTS AND METHOD

A retrospective analysis of children on the waiting list in the last 4 years was carried out. Data of patients who died while on the waiting list (WL) were recorded. Transplanted patients were divided according to the type of graft: whole liver, split, living donor and reduced liver. The analyzed outcome variables were: age, weight, UNOS status, cause of liver failure, complications and graft and patient survival. Comparisons between types of graft were performed by using Kaplan-Meier, log-rank, chi (2) and Kruskal-Wallis tests.

RESULTS

During the period studied, 116 children were listed for liver transplantation. Of these 116 children, nine (7.7 %) died after a mean period of 40.5 (5-175) days waiting for a suitable graft. Their median age at inclusion was 214 (35-1607) days, and median weight was 7.2 (12.3-3.6) kg. The cause of liver failure in this group was: 1 hemochromatosis, 1 hepatoblastoma, 2 biliary atresia, 2 acute liver failure, 2 primary non-function (PNF) and 1 chronic rejection. Liver transplantation was performed in 103 children: 25 (24 %) whole livers, 17 (16.5 %) split, 29 (28 %) living donor, 32 (31 %) reduced and 4 remain on the waiting list. Recipient age and weight were significantly lower in those receiving split and living donor than in those who given whole livers. Patient and graft survival were similar in all groups although there was a trend to lower graft survival in patients receiving whole livers. More than 50 % of patients with UNOS status I received a split graft and 5/6 children with hepatoblastoma underwent living donor transplantation. There were no differences in the rate of acute vascular complications, but long-term biliary complications were more frequent in split and living donor grafts.

CONCLUSIONS

As long as the goal of zero mortality for children on the waiting list is not achieved, variant techniques will be necessary in pediatric liver transplantation programs. Split and living donor were employed mostly to treat younger children and particularly those with a higher UNOS status. Children with tumors were treated mainly with living donor grafts. Variant techniques, which are absolutely necessary in a pediatric program, need to be improved in order to avoid long-term biliary complications.

Long-term results of the treatment of total colonic aganglionosis with two different techniques

AIM

Aim of this study was to assess the long-term results of the treatment of total colonic aganglionosis (TCA) with 2 different techniques in terms of growth, continence and quality of life (QOL).

PATIENTS AND METHODS

Forty-one patients treated for TCA between 1972 and 2007 were reviewed retrospectively with special attention paid to the length of aganglionosis, complications, growth, continence and QOL. Until 1992, patients underwent subtotal colonic resection and side-to-side ileosigmoid anastomosis (modified Martin). Since 1992, straight ileo-anal pull-through was preferred. At the end of follow-up (median 18 years, range 1-35), the height and weight, continence and QOL (scoring feeding habits, school/work performance, family life and professional development) were assessed by clinical visit or phone interview.

RESULTS

Twenty-eight patients were male and 13 female. Six had total intestinal aganglionosis and were excluded from this review together with the 2 who died before definitive treatment. The 33/41 persons in whom aganglionosis had involved less than 50 cm above the ileocecal valve and who had been considered suitable for the reestablishment of transanal fecal flow were included. Eighteen children underwent a modified Martin and 15 straight ileo-anal pull-through. Postoperative intestinal obstruction occurred in 4 cases, prolapse and prolonged TPN requirement in 2, and wound disruption and fistula in 1. Thirteen patients (39 %) had postoperative enterocolitis. Two children died after operation (1 wound disruption with sepsis and 1 pneumonia). Out of 31 survivors, 57 % and 53 % were > p50 with regard to height and weight whereas only 15 % and 19 % were <p3 respectively. Only half the patients had more than 3 bowel movements per day and the median Wildhaber continence score (normal = 14) was 11 (range 6-14). Both types of operations resulted in comparable defecation and continence patterns. QOL was rated as good in all cases but one. All patients but 2 attended high school, 8 attend university, 4 are employed and 1 is married and has 2 daughters. Social life is normal except for 1 patient who perceives his disease as a burden.

CONCLUSIONS

Patients with TCA amenable to reestablishment of the transanal fecal flow can have adequate growth, normal feeding, reasonably good continence and satisfactory QOL. However, complications and enterocolitis are frequent. A modified Martin's procedure was performed as well as straight ileo-anal pull-through with little influence on the long-term outcome.

Surgery of liver tumors in children in the last 15 years

AIM

Aim of the study was to review our experience in the management of liver tumors in children over the last 15 years.

PATIENTS AND METHODS

A cohort of 78 children with liver tumors managed in our institution between 1991 and 2006 was retrospectively reviewed. There were 45 males and 33 females with a mean age of 32 +/- 41 months at diagnosis. Most tumors were malignant (n = 57); the most frequently occurring tumor was hepatoblastoma (n = 47), followed by hepatocarcinoma (n = 5), sarcoma (n = 4), and lymphoma (n = 1). Vascular tumors (n = 12) predominated among the benign tumors followed by mesenchymal hamartoma (n = 4), focal nodular hyperplasia (n = 3), adenoma (n = 1), and inflammatory pseudotumor (n = 1). We reviewed the epidemiologic features, clinical presentation, diagnosis, treatment and outcomes. We employed MRI and angio-CT for SIOPEL PRETEXT staging and selected the management accordingly for malignant tumors. We analyzed the long-term survival using Kaplan-Meier curves.

RESULTS

Benign tumors had an excellent outcome with both medical or surgical management. Of the malignant tumors 4 were PRETEXT I and were treated by left lateral segmentectomy with 100 % survival; 20 were PRETEXT II (12 left and 8 right lobe) and were treated by lobectomy of the corresponding side, except for 1 case which required OLT (90 % survival); 9 children had PRETEXT III tumors requiring trisegmentectomy or extended lobectomies with OLT in 1 case (77.7 % survival). Fourteen children had PRETEXT IV tumors: 10 received OLT and 9 of them are still alive (64.2 % survival). Overall survival was 80.8 %, and actuarial survival at 6 years was 82.2 %. Other malignant tumors had variable results.

CONCLUSIONS

Outcomes have improved much in the last years. Surgical removal is necessary in most cases. Transplantation is a very useful adjunct. Treatment of these tumors should be concentrated in centers with expertise.

[What can we do when a esophagocoloplasty fails?]

BACKGROUND

Postoperative complications of esophageal replacement are potentially severe, and they can even make impossible the digestive continuity. However, several surgical options have been used for such situations. The aim of the study is to assess the early and late results in patients who have been managed or referred to our department for this problem.

PATIENTS AND METHODS

We reviewed 8 patients operated between 1975 and 2005, four of them were referred from other hospitals. The ranging in age was from 4 months and 23 years at the moment of the first colonic replacement, and who required a second plasty because of intra or postoperative complications. The esophagocoloplasty was retrosternal in 6 cases and transhiatal in 2, with a left colon graft in 6, ileocolonic in I and right colon in the last one. The initial diagnosis was traqueoesophageal fistula in 6 (type III in 3, type I in 2 and IV in 1), caustic injury in 1 and herpetic esophagitis in 1. Complications requiring reoperation were stricture of the cervical esophagococolic anastomosis because of postoperative dehiscence (n=4), perioperative deficient graft vascularisation (n=2), graft necrosis (n= 1) and symptomatic gastric-colic reflux (n=l).

RESULTS

The deficient graft irrigation was detected and managed during the surgical procedure in 2 cases, left colonic graft was remplaced by a gastric tube and the right colon, respectively, with excellent results. Repeated endoscopic dilatations (n=4) as well as surgical revision with resection and reanastomosis of the stenotic segment (n=2), did not suffice in children with severe strictures (100%). A second plasty was tried in 2 patients: a failed microsurgical sigmoid graft in one of them, and a presternal esophagocoloplasty with a left colonic graft in the other one. It was impossible to perform a new plasty in two chidren, because of the severe mediastinal fibrosis. One patient was referred with severe gastro-colic reflux and the cologastric anastomosis and the gastrostomy were refashioned. Another patient with graft necrosis required total resection of the coloplasty and a new esophagostomy and gastrostomy. 50% of the patients recovered digestive continuity, and nowadays three of them eat normally. The fourth one died after several years because of an Guillain Barré syndrome. Four patients are still waiting for future attempts of esophageal substitution.

CONCLUSIONS

There are surgical options to reestablish the digestive continuity whenever the initial esophageal replacement fails. Severe postoperative strictures do not dissapear with endoscopic dilatations or stenotic resection and reanastomosis, but they usually require a new graft in another less injured place. Poor vascularisation of the graft can be prevented, giving the best solution for each patient, and at minimal suspicion of ischemia, consider another plasty or access during the operation.

Liver transplantation for malignant tumours in children

OBJECTIVE

The object of this study was to analyse our results with liver transplantation (LTX) for primitive malignant unresectable liver tumours in children and to discuss the controversial indications, based on our experience.

METHODS/PATIENTS

We report on 12 patients, aged 6 months to 14 years, with hepatic malignant tumours: 11 with hepatoblastoma and 1 with fibrolamellar hepatocelullar carcinoma without cirrhosis. LTX was the primary treatment in 10 patients (PRETEXT IV or any grade, if there was extension to the retrohepatic vena cava, 3 hepatic veins or portal vein) and a rescue therapy after recurrence for 1 and for persistence of unresectable macroscopic residuals in 2 patients. One of the patients who underwent a LTX as primary therapy had lung metastases previously resolved with chemotherapy. We used entire liver (n = 5), left lateral segment from cadaveric donor (n = 3), living related donor (n = 3; 2 segments II-III and 1 right lobe) and left lateral segment from split liver (n = 1). All children received chemotherapy prior and post transplantation following the SIOPEL protocol. We analysed procedure tolerance, survival, recurrence rate, disease-free period and risk factors for adverse evolution.

RESULTS

All patients overcame LTX and no early graft loss was recorded. Two cases died because of tumour relapse, 1 after primary LTX and 1 after rescue LTX (survival rate of both groups, 90% and 50%). Graft and patient survival rates at 1 year, 3 years, 5 years and 14 years were 91%, 91%, 82% and 82% respectively. The boy who presented with lung metastases developed new ones one year after LTX that were removed and he is currently free of disease. The disease-free period has a probability at 1, 3 and 5 years of 91%, 75% and 75%, respectively. Tumour tissue persistence was the only risk factor for an adverse clinical course in our series.

CONCLUSIONS

LTX is a reasonable therapeutic approach for unresectable malignant liver tumours, providing outcomes comparable to those for resectable tumours. Results obtained with LTX are better when it is used as a primary treatment than when used as a rescue procedure. Proper staging and early referral to centres with enough expertise optimise the results. LTX for patients with lung metastases could be a controversial option. Living related-donor transplantation is an excellent alternative to avoid disease progression while on the waiting list for cadaveric donors.

A prevalent POLG CAG microsatellite length allele in humans and African great apes

The human nuclear gene for the catalytic subunit of mitochondrial DNA polymerase gamma ( POLG) contains within its coding region a CAG microsatellite encoding a polyglutamine repeat. Previous studies demonstrated an association between length variation at this repeat and male infertility, suggesting a mechanism whereby the prevalent (CAG)(10) allele, which occurs at a frequency of >80% in different populations, could be maintained by selection. Sequence analysis of the POLG CAG microsatellite region of more than 1000 human chromosomes reveals that virtually all allelic variation at the locus is accounted for by length variation of the CAG repeat. Analysis of POLG from African great apes shows that a prevalent length allele is present in each species, although its exact length is species-specific. In common chimpanzee ( Pan troglodytes) a number of different sequence variants contribute to the prevalent length allele, strongly supporting the idea that the length of the POLG microsatellite region, rather than its exact nucleotide or amino acid sequence, is what is maintained. Analysis of POLG in other primates indicates that the repeat has expanded from a shorter, glutamine-rich sequence, present in the common ancestor of Old and New World monkeys.