Single center results of simultaneous pancreas-kidney transplantation in patients with type 2 diabetes.

Studies have found similar outcomes of Simultaneous Pancreas-Kidney transplantation (SPKT) in patients with Type 2 (T2D) and Type 1 diabetes (T1D). However, there are scarce data evaluating the association of recipient factors such as age, BMI, or pretransplant insulin requirements with outcomes, thus the criteria for the optimal recipient selection remains unclear. In this study, 284 T1D and 39 T2D patients, who underwent SPKT between 2006 and 2017 with 1 year of follow-up at minimum, were assessed for potential relationship of pretransplant BMI and insulin requirements with posttransplant diabetes and pancreatic graft failure. Kaplan-Meier analysis showed similar rates of freedom from posttransplant diabetes (94.7% T2D vs. 92.3% T1D at 1 yr, and 88.1% T2D vs. 81.1% T1D at 5 yrs) and graft survival (89.7% T2D vs. 90.4% T1D at 1 yr, and 89.7% T2D vs. 81.2% T1D at 5 yrs). There was no significant association between BMI or pretransplant insulin requirements with posttransplant diabetes occurrence in either T1D (p = .10, .43, respectively) or T2D (p = .12, .63) patients in the cohort; or with graft failure (T1D: p = .40, .09; T2D: p = .71, .28). These observations suggest a less restricted approach to selective use of SPKT in patients with T2D.

Prevalence and outcomes of cystic lesions of the transplant pancreas: The University of Wisconsin Experience.

Literature on the behavior of cystic lesions in pancreas transplants is scarce, and hence a better understanding is warranted. Data on recipients and their respective donors that underwent simultaneous kidney and pancreas, pancreas transplant alone, and pancreas after kidney between 1994 and 2015 were reviewed (n = 1185). Cystic lesions of the transplant pancreas developed in 22 patients (1.8%): 12 pseudocysts, 2 cysts/remnants, 4 intraductal papillary mucinous neoplasms (IPMN), 2 adenocarcinomas, 1 low-grade intraepithelial pancreatic neoplasia, and 1 case of polycystic kidney disease. The median size was 3.6 cm (1.6-5.5 cm), and occurred at a median time of 65.5 months (2-183 months) posttransplant. The median age of the graft at time of diagnosis was 42 years (25.7-54.5), with 17 of 22 grafts (77%) functioning at time of diagnosis. Triggers for investigation were elevations in pancreatic enzymes, re-admissions for abdominal pain, and incidentalomas. High-resolution imaging and diagnostic biopsy/aspiration with ancillary tests were the main diagnostic tests. Most pseudocysts were managed by percutaneous drainage, and although no firm inference can be made from such a small series, we have observed that the behavior and management of IPMN and adenocarcinoma in the pancreas graft appears congruent to that of the native pancreas.

Intraspecific ecological niche divergence and reproductive shifts foster cytotype displacement and provide ecological opportunity to polyploids.

Background and Aims: Niche divergence between polyploids and their lower ploidy progenitors is one of the primary mechanisms fostering polyploid establishment and adaptive divergence. However, within-species chromosomal and reproductive variability have usually been neglected in community ecology and biodiversity analyses even though they have been recognized to play a role in the adaptive diversification of lineages. Methods: We used Paspalum intermedium, a grass species with diverging genetic systems (diploidy vs. autopolyploidy, allogamy vs. autogamy and sexuality vs. apomixis), to recognize the causality of biogeographic patterns, adaptation and ecological flexibility of cytotypes. Chromosome counts and flow cytometry were used to characterize within-species genetic systems diversity. Environmental niche modelling was used to evaluate intraspecific ecological attributes associated with environmental and climatic factors and to assess correlations among ploidy, reproductive modes and ecological conditions ruling species' population dynamics, range expansion, adaptation and evolutionary history. Key Results: Two dominant cytotypes non-randomly distributed along local and regional geographical scales displayed niche differentiation, a directional shift in niche optima and signs of disruptive selection on ploidy-related ecological aptitudes for the exploitation of environmental resources. Ecologically specialized allogamous sexual diploids were found in northern areas associated with higher temperature, humidity and productivity, while generalist autogamous apomictic tetraploids occurred in southern areas, occupying colder and less productive environments. Four localities with a documented shift in ploidy and four mixed populations in a zone of ecological transition revealed an uneven replacement between cytotypes. Conclusions: Polyploidy and contrasting reproductive traits between cytotypes have promoted shifts in niche optima, and increased ecological tolerance and niche divergence. Ecologically specialized diploids maintain cytotype stability in core areas by displacing tetraploids, while broader ecological preferences and a shift from sexuality to apomixis favoured polyploid colonization in peripheral areas where diploids are displaced, and fostered the ecological opportunity for autotetraploids supporting range expansion to open southern habitats.

Comparative analysis of molecular and morphological diversity in two diploid Paspalum species (Poaceae) with contrasting mating systems.

KEY MESSAGE: Interspecific comparison of two Paspalum species has demonstrated that mating systems (selfing and outcrossing) contribute to variation (genetically and morphologically) within species through similar but mutually exclusive processes. Mating systems play a key role in the genetic dynamics of populations. Studies show that populations of selfing plants have less genetic diversity than outcrossing plants. Yet, many such studies have ignored morphological diversity. Here, we compared the morphological and molecular diversity patterns in populations of two phylogenetically-related sexual diploids that differ in their mating system: self-sterile Paspalum indecorum and self-fertile P. pumilum. We assessed the morphological variation using 16 morpho-phenological characters and the molecular diversity using three combinations of AFLPs. We compared the morphological and molecular diversity within and among populations in each mating system. Contrary to expectations, selfers showed higher morphological variation within populations, mainly in vegetative and phenological traits, compared to outcrossers. The high morphological variation within populations of selfers led to a low differentiation among populations. At molecular level, selfing populations showed lower levels of genotypic and genetic diversity than outcrossing populations. As expected, selfers showed higher population structure than outcrossers (PhiST = 0.301 and PhiST = 0.108, respectively). Increased homozygous combinations for the same trait/locus enhance morphological variation and reduce molecular variation within populations in selfing P. pumilum. Thus, selfing outcomes are opposite when comparing morphological and molecular variation in P. pumilum. Meanwhile, pollen flow in obligate outcrossing populations of P. indecorum increases within-population molecular variation, but tends to homogenize phenotypes within-population. Pollen flow in obligate outcrossers tends to merge geographically closer populations; but isolation by distance can lead to a weak differentiation among distant populations of P. indecorum.

Competition between meiotic and apomictic pathways during ovule and seed development results in clonality.

Meiotic and apomictic reproductive pathways develop simultaneously in facultative aposporous species, and compete to form a seed as a final goal. This developmental competition was evaluated in tetraploid genotypes of Paspalum malacophyllum in order to understand the low level of sexuality in facultative apomictic populations. Cyto-embryology on ovules, flow cytometry on seeds and progeny tests by DNA fingerprinting were used to measure the relative incidence of each meiotic or apomictic pathway along four different stages of the plant's life cycle, namely the beginning and end of gametogenesis, seed formation and adult offspring. A high variation in the frequencies of sexual and apomictic pathways occurred at the first two stages. A trend of radical decline in realized sexuality was then observed. Sexual and apomictic seeds were produced, but the efficiency of the sexual pathway dropped drastically, and exclusively clonal offspring remained. Both reproductive pathways are unstable at the beginning of development, and only the apomictic one remains functional. Key factors reducing sexuality are the faster growth and parthenogenetic development in the aposporous pathway, and an (epi)genetically negative background related to the extensive gene de-regulation pattern responsible for apomixis. The effects of inbreeding depression during post-fertilization development may further decrease the frequency of effective sexuality.

Harnessing apomictic reproduction in grasses: what we have learned from Paspalum.

BACKGROUND: Apomixis is an alternative route of plant reproduction that produces individuals genetically identical to the mother plant through seeds. Apomixis is desirable in agriculture, because it guarantees the perpetuation of superior genotypes (i.e. heterotic hybrid seeds) by self-seeding without loss of hybrid vigour. The Paspalum genus, an archetypal model system for mining apomixis gene(s), is composed of about 370 species that have extremely diverse reproductive systems, including self-incompatibility, self-fertility, full sexual reproduction, and facultative or obligate apomixis. Barriers to interspecific hybridization are relaxed in this genus, allowing the production of new hybrids from many different parental combinations. Paspalum is also tolerant to various parental genome contributions to the endosperm, allowing analyses of how sexually reproducing crop species might escape from dosage effects in the endosperm. SCOPE: In this article, the available literature characterizing apomixis in Paspalum spp. and its use in breeding is critically reviewed. In particular, a comparison is made across species of the structure and function of the genomic region controlling apomixis in order to identify a common core region shared by all apomictic Paspalum species and where apomixis genes are likely to be localized. Candidate genes are discussed, either as possible genetic determinants (including homologs to signal transduction and RNA methylation genes) or as downstream factors (such as cell-to-cell signalling and auxin response genes) depending, respectively, on their co-segregation with apomixis or less. Strategies to validate the role of candidate genes in apomictic process are also discussed, with special emphasis on plant transformation in natural apomictic species.

Sequence characterization, in silico mapping and cytosine methylation analysis of markers linked to apospory in Paspalum notatum.

In previous studies we reported the identification of several AFLP, RAPD and RFLP molecular markers linked to apospory in Paspalum notatum. The objective of this work was to sequence these markers, obtain their flanking regions by chromosome walking and perform an in silico mapping analysis in rice and maize. The methylation status of two apospory-related sequences was also assessed using methylation-sensitive RFLP experiments. Fourteen molecular markers were analyzed and several protein-coding sequences were identified. Copy number estimates and RFLP linkage analysis showed that the sequence PnMAI3 displayed 2-4 copies per genome and linkage to apospory. Extension of this marker by chromosome walking revealed an additional protein-coding sequence mapping in silico in the apospory-syntenic regions of rice and maize. Approximately 5 kb corresponding to different markers were characterized through the global sequencing procedure. A more refined analysis based on sequence information indicated synteny with segments of chromosomes 2 and 12 of rice and chromosomes 3 and 5 of maize. Two loci associated with apomixis locus were tested in methylation-sensitive RFLP experiments using genomic DNA extracted from leaves. Although both target sequences were methylated no methylation polymorphisms associated with the mode of reproduction were detected.

Combined Tricuspid Valve Repair and Orthotopic Liver Transplantation in a Patient With Severe Tricuspid Regurgitation and Pulmonary Hypertension.

Severe pulmonary hypertension and severe tricuspid regurgitation are often considered strict contraindications for orthotopic liver transplantation. A combined approach of tricuspid repair and subsequent liver transplantation could provide a novel approach for patients with severe pulmonary hypertension and tricuspid regurgitation to undergo orthotopic liver transplantation. A 62-year-old male with a history of end-stage renal disease on hemodialysis, cirrhosis, and third-degree atrioventricular heart block status post single lead pacemaker insertion presented for an orthotopic liver transplant. However, after placement of a Swan-Ganz catheter by the anesthesia team, the patient's central venous pressure was found to be high, and his mean pulmonary artery pressure was 40 mmHg. His case was canceled due to concern for poor postoperative outcomes after a subsequent transesophageal echocardiogram revealed a severely dilated right heart and 4+ tricuspid regurgitation with flow reversal into the hepatic veins. After discussion among the hospital's transplant committee, the patient was planned to have a tricuspid valve repair, liver transplant, and kidney transplant surgery several months later. The patient successfully underwent tricuspid valve repair and orthotopic liver transplant and then kidney transplant the following day.

Dallas UtErus Transplant Study: Early Outcomes and Complications of Robot-assisted Hysterectomy for Living Uterus Donors.

BACKGROUND: Uterus transplantation is a treatment for absolute uterine infertility and can be performed with living and deceased donors. Given the safety and increased utilization of robotic assistance with other gynecologic and transplant donor operations, we adopted a robot-assisted approach to donor hysterectomy. This study compared early outcomes and morbidity of the robot-assisted approach to donor hysterectomy with the traditionally performed open approach and addressed whether the robot-assisted approach is safe and offers advantages for the donor. METHODS: Our institution has performed 18 living donor hysterectomies for uterus transplantation. This retrospective review compared the last 5 cases utilizing a robot-assisted technique and vaginal extraction of the uterus graft with the first 13 cases performed with an open laparotomy technique. Demographic, intraoperative, and postoperative data were examined. RESULTS: There were no differences between the robot-assisted and the open living donor group with respect to age, body mass index, or gynecological history. Although the median operative time was shorter for the open approach (6.27 versus 10.46 h), the donors' median estimated blood loss, length of hospital stay, and length of sick leave were less with the robot-assisted approach. There was no conversion to open hysterectomy in the robot-assisted cases, and the incidence of complications was similar between the 2 groups. There was no difference in early graft function. CONCLUSIONS: These preliminary results show that robot-assisted living donor hysterectomy is feasible and safe for the donors; it allows a faster postoperative recovery and the same early graft function.

Sexual modulation in a polyploid grass: a reproductive contest between environmentally inducible sexual and genetically dominant apomictic pathways.

In systems alternating between sexual and asexual reproduction, sex increases under unfavorable environmental conditions. In plants producing sexual and asexual (apomictic) seeds, studies on the influence of environmental factors on sex are equivocal. We used Paspalum intermedium to study environmental effects on the expression of sexual and apomictic developments, and on resulting reproductive fitness variables. Flow cytometric and embryological analyses were performed to characterize ploidy and reproductive modes, and effects of local climatic conditions on sexual and apomictic ovule and seed frequencies were determined. Seed set and germination data were collected and used to estimate reproductive fitness. Frequencies of sexual and apomictic ovules and seeds were highly variable within and among populations. Apomictic development exhibited higher competitive ability but lower overall fitness. Frequencies of sexual reproduction in facultative apomictic plants increased at lower temperatures and wider mean diurnal temperature ranges. We identified a two-fold higher fitness advantage of sexuality and a Tug of War between factors intrinsic to apomixis and environmental stressors promoting sexuality which influence the distribution of sex in apomictic populations. This points toward a crucial role of local ecological conditions in promoting a reshuffling of genetic variability that may be shaping the adaptative landscape in apomictic P. intermedium plants.

Reproductive Systems in Paspalum: Relevance for Germplasm Collection and Conservation, Breeding Techniques, and Adoption of Released Cultivars.

The objective of this review is to analyze and describe the impact that mode of reproduction in Paspalum has on germplasm conservation, genetic improvement, and commercialization of cultivars. Germplasm collection and conservation can now be rethought considering the newly available information related to how diversity is allocated in nature and how it can be transferred between the sexual and apomictic germplasm using novel breeding approaches. An inventory of species and accessions conserved around the world is analyzed in relation to the main germplasm banks. Because of the importance of apomixis in Paspalum species different breeding approaches have been used and tested. Knowledge related to the inheritance of apomixis, variable expressivity of the trait and techniques for early identification of apomicts has helped to improve the efficiency of the breeding methods. Novel breeding techniques are also being developed and are described regarding its advantages and limitations. Finally, the impact of reproductive mode on the adoption of the released cultivars is discussed.

Segregation for sexual seed production in Paspalum as directed by male gametes of apomictic triploid plants.

BACKGROUND AND AIMS: Gametophytic apomixis is regularly associated with polyploidy. It has been hypothesized that apomixis is not present in diploid plants because of a pleiotropic lethal effect associated with monoploid gametes. Rare apomictic triploid plants for Paspalum notatum and P. simplex, which usually have sexual diploid and apomictic tetraploid races, were acquired. These triploids normally produce male gametes through meiosis with a range of chromosome numbers from monoploid (n = 10) to diploid (n = 20). The patterns of apomixis transmission in Paspalum were investigated in relation to the ploidy levels of gametes. METHODS: Intraspecific crosses were made between sexual diploid, triploid and tetraploid plants as female parents and apomictic triploid plants as male parents. Apomictic progeny were identified by using molecular markers completely linked to apomixis and the analysis of mature embryo sacs. The chromosome number of the male gamete was inferred from chromosome counts of each progeny. KEY RESULTS: The chromosome numbers of the progeny indicated that the chromosome input of male gametes depended on the chromosome number of the female gamete. The apomictic trait was not transmitted through monoploid gametes, at least when the progeny was diploid. Diploid or near-diploid gametes transmitted apomixis at very low rates. CONCLUSIONS: Since male monoploid gametes usually failed to form polyploid progenies, for example triploids after 4x x 3x crosses, it was not possible to determine whether apomixis could segregate in polyploid progenies by means of monoploid gametes.

Determination by Multi-NMR Studies of New Stable Aluminum Complexes with Pyrophosphate and Fluoride in Aqueous Solution.

Multi-NMR studies ((27)Al, (19)F, (31)P) show that, in the presence of pyrophosphate at pH 7, fluoride and aluminum (Al(3+)) ions combine in aqueous solution, to generate a wide variety of ternary complexes. Among the latter, a new class of stable complexes, showing J(FF) and J(FP) coupling constants, has been identified in which two octahedral aluminum cations are bound by two pyrophosphate moieties, with a common fluorine atom bridging the two aluminum ions. Both the pyrophosphate groups and the fluoride ion contribute to the stability of these molecules. The existence of J(FF) couplings provides evidence for the octahedral coordination of aluminum in these complexes.