Robotic kidney transplantation in the obese patient: 10‐year experience from a single center

Despite increasing obesity rates in the dialysis population, obese kidney transplant candidates are still denied transplantation by many centers. We performed a single‐center retrospective analysis of a robotic‐assisted kidney transplant (RAKT) cohort from January 2009 to December 2018. A total of 239 patients were included in this analysis. The median BMI was 41.4 kg/m², with the majority (53.1%) of patients being African American and 69.4% of organs sourced from living donors. The median surgery duration and warm ischemia times were 4.8 hours and 45 minutes respectively. Wound complications (mostly seromas and hematomas) occurred in 3.8% of patients, with 1 patient developing a surgical site infection (SSI). Seventeen (7.1%) graft failures, mostly due to acute rejection, were reported during follow‐up. Patient survival was 98% and 95%, whereas graft survival was 98% and 93%, at 1 and 3 years respectively. Similar survival statistics were obtained from patients undergoing open transplant over the same time period from the UNOS database. In conclusion, RAKT can be safely performed in obese patients with minimal SSI risk, excellent graft function, and patient outcomes comparable to national data. RAKT could improve access to kidney transplantation in obese patients due to the low surgical complication rate.     

Effects of Odanacatib on Bone Structure and Quality in Postmenopausal Women With Osteoporosis: 5-Year Data From the Phase 3 Long-Term Odanacatib Fracture Trial (LOFT) and its Extension

Odanacatib (ODN), a selective oral inhibitor of cathepsin K, was an investigational agent previously in development for the treatment of osteoporosis. In this analysis, the effects of ODN on bone remodeling/modeling and structure were examined in the randomized, double-blind, placebo-controlled, event-driven, Phase 3, Long-term Odanacatib Fracture Trial (LOFT; NCT00529373) and planned double-blind extension in postmenopausal women with osteoporosis. A total of 386 transilial bone biopsies, obtained from consenting patients at baseline (ODN n = 17, placebo n = 23), month 24 (ODN n = 112, placebo n = 104), month 36 (ODN n = 42, placebo n = 41), and month 60 (ODN n = 27, placebo n = 20) were assessed by dynamic and static bone histomorphometry. Patient characteristics at baseline and BMD changes over 5 years for this subset were comparable to the overall LOFT population. Qualitative assessment of biopsies revealed no abnormalities. Consistent with the mechanism of ODN, osteoclast number was higher with ODN versus placebo over time. Regarding bone remodeling, dynamic bone formation indices in trabecular, intracortical, and endocortical surfaces were generally similar in ODN-treated versus placebo-treated patients after 2 years of treatment. Regarding periosteal modeling, the proportion of patients with periosteal double labels and the bone formation indices increased over time in the ODN-treated patients compared with placebo. This finding supported the observed numerical increase in cortical thickness at month 60 versus placebo. In conclusion, ODN treatment for 5 years did not reduce bone remodeling and increased the proportion of patients with periosteal bone formation. These results are consistent with the mechanism of action of ODN, and are associated with continued BMD increases and reduced risk of fractures compared with placebo in the LOFT Phase 3 fracture trial. © 2020 American Society for Bone and Mineral Research.     

Preoperative extracorporeal membrane oxygenation for postinfarction ventricular septal defect: Case series of three patients with a literature review

The mortality rate after the development of postinfarction ventricular septal defect (VSD) remains high, despite progress in pharmacologic therapy, invasive cardiology, and surgical techniques. We present three cases of preoperative venoarterial extracorporeal membrane oxygenation as a bridge to reparative surgical repair in patients with cardiogenic shock who would otherwise require emergent cardiac surgery with an associated risk. Two patients were discharged, whereas the third patient died due to pulmonary artery rupture after a right ventricular assist device implantation, despite the fact that he had a successful bridge to reparative surgery and VSD repair. Finally, a review of the current literature concerning the use of preoperative venoarterial extracorporeal membrane oxygenation as a bridge to reparative surgery is provided.     

Strong YB-1 Expression Predicts Liver Recurrence Following Resection for Colorectal Metastases

Introduction

The Y-box binding protein-1 (YB-1) is a multifunctional oncoprotein involved in the proliferation and aggressiveness of cancer cells. The aim of this study was to determine whether strong YB-1 expression in neoplastic cells of colorectal liver metastases (CRLM) may have an impact on liver disease-free survival following liver resection.

Materials and Methods

Immunohistochemistry was performed to evaluate YB-1 in 66 patients who underwent liver resection for CRLM. YB-1 expression was classified as weak (low-staining intensity) and strong (high-staining intensity).

Results

YB-1 expression was observed in the cytoplasm of all CRLM. YB-1 expression was weak in 17 patients (25.8 %) and strong in 49 patients (74.2 %). Liver recurrence rate was significantly higher in the strong than in the weak expression group: 55.1 vs. 23.5 % (p?=?0.023). Multivariable logistic regression analysis showed that YB-1 strong expression was the only independent risk factor for liver recurrence. The 5-year specific liver disease-free survival rate was 76.0 % in the weak expression group and 41.5 % in the strong expression group (p?=?0.034). These results were not influenced by clinical prognostic factors of tumor recurrence.

Conclusions

This is the first study showing that the degree of YB-1 expression in tissue specimens of CRLM predicts liver recurrence following liver resection.     

Dissecting human cytomegalovirus gene function and capsid maturation by ribozyme targeting and electron cryomicroscopy

Human CMV (HCMV) is the leading viral cause of birth defects and causes one of the most common opportunistic infections among transplant recipients and AIDS patients. Cleavage of internal scaffolding proteins by the viral protease (Pr) occurs during HCMV capsid assembly. To gain insight into the mechanism of HCMV capsid maturation and the roles of the Pr in viral replication, an RNase P ribozyme was engineered to target the Pr mRNA and down-regulate its expression by >99%, generating premature Pr-minus capsids. Furthermore, scaffolding protein processing and DNA encapsidation were inhibited by 99%, and viral growth was reduced by 10,000-fold. 3D structural comparison of the Pr-minus and wild-type B capsids by electron cryomicroscopy, at an unprecedented 12.5-angstroms resolution, unexpectedly revealed that the structures are identical in their overall shape and organization. However, the Pr-minus capsid contains tenuous connections between the scaffold and the capsid shell, whereas the wild-type B capsid has extra densities in its core that may represent the viral Pr. Our findings indicate that cleavage of the scaffolding protein is not associated with the morphological changes that occur during capsid maturation. Instead, the protease appears to be required for DNA encapsidation and the subsequent maturation steps leading to infectious progeny. These results therefore provide key insights into an essential step of HCMV infection using an RNase P ribozyme-based inhibition strategy.     

Three novel mutations in CYP21 gene in Brazilian patients with the classical form of 21-hydroxylase deficiency due to a founder effect

Three different new mutations were found after CYP21 gene sequencing in three unrelated patients with the classical form of the 21-hydroxylase deficiency. These mutations were also screened in their affected relatives. In one patient and her brother, both affected with the simple virilizing form and in their aunt, with the nonclassical form, an AG>GG transition was found in the acceptor site of intron 2. In another patient with the salt wasting form, we found a 1003 1004 insA, in exon 4, that altered the reading frame and created a stop codon in codon 297. In the third patient and his sister, we found a C>T transition in codon 408. This transition led to the substitution of arginine by cysteine (R408C) in a conserved region where arginine is conserved in at least four different species. These siblings with the R408C mutation, both affected with the salt wasting form, have the IVS2-13A/C>G mutation in the other allele, suggesting that the R408C should lead to complete impairment of enzymatic activity. To rule out the possibility of polymorphism, R408C was screened through allele specific PCR, and it was not found in 100 normal alleles. The screening of these three new mutations by allele-specific PCR or enzymatic restriction in 212 CAH patients disclosed their presence in 2.3% (9/387) of the alleles. All three new mutations were found in compound heterozygous state with previously known mutations. Microsatellite studies, using markers flanking CYP21 gene, revealed that each new mutation presents the same haplotype, suggesting a gene founder effect, similar to what was previously observed with the G424S mutation also described in our population. Although microconversion events are the main cause of mutations in the CYP21 gene, random mutations with a common origin can also be the cause of 21-hydroxylase deficiency.     

Cholesteryl esters stabilize human CD1c conformations for recognition by self-reactive T cells

Cluster of differentiation 1c (CD1c)-dependent self-reactive T cells are abundant in human blood, but self-antigens presented by CD1c to the T-cell receptors of these cells are poorly understood. Here we present a crystal structure of CD1c determined at 2.4 Å revealing an extended ligand binding potential of the antigen groove and a substantially different conformation compared with known CD1c structures. Computational simulations exploring different occupancy states of the groove reenacted these different CD1c conformations and suggested cholesteryl esters (CE) and acylated steryl glycosides (ASG) as new ligand classes for CD1c. Confirming this, we show that binding of CE and ASG to CD1c enables the binding of human CD1c self-reactive T-cell receptors. Hence, human CD1c adopts different conformations dependent on ligand occupancy of its groove, with CE and ASG stabilizing CD1c conformations that provide a footprint for binding of CD1c self-reactive T-cell receptors.Cluster of differentiation 1 (CD1) proteins are a family of MHC class I-like glycoproteins that present lipid antigens to T cells. CD1 restricted T cells are abundant in humans and play important roles in host defense and immune regulation. Human CD1 proteins comprise five CD1 isoforms, CD1a, CD1b, CD1c, CD1d, and CD1e, which exhibit different intracellular trafficking behaviors and ligand binding preferences (1). Structurally, the main differences between these CD1 isoforms lie in the architecture of their lipophilic ligand binding grooves. Whereas all CD1 isoforms share a highly conserved A′ channel (or pocket) for binding C18–C26 acyl chains, specialization is provided by further connecting channels (2–7). In CD1a, the A′ channel is “fused” to a wide and shallow F′ channel, enabling binding of lipopeptides such as mycobacterial didehydroxymycobactin (DDM) (8). CD1b features a unique T′ tunnel that connects A′ and F′, thereby forming a “superchannel” for accommodating very long acyl chains (e.g., mycobacterial mycolates) (2, 4). CD1d, the only isoform also conserved in rodents, exhibits a two-branched ligand binding groove with two linear channels A′ and F′ connected near the main portal into the groove, known as the F′ portal. A similar two-branched arrangement of A′ and F′ is seen in CD1e, the only CD1 isoform not expressed on the cell surface. Compared with CD1d, CD1a, and CD1b, the portal into the groove in CD1e is widely exposed, consistent with its known role in lipid transfer processes inside lysosomes (6).CD1c presents foreign- (9, 10) as well as self-lipid antigens to T cells (11). Two recent crystal structures of human CD1c revealed a two-branched design similar to that of CD1d and CD1e, with two channels A′ and F′ connecting near the groove portal. In these structures, a mycobacterial phosphomycoketide (PM) or mannosyl-β1-phosphomycoketide (MPM) occupied the A′ channel, whereas an undefined short ligand was present in the F′ channel (7, 12). The spatial arrangement of these ligands in the CD1c groove was very similar to and virtually overlapping in 3D comparisons with that of alpha-galactosylceramide (αGC) in human CD1d (Fig. S1 A and B). Because CD1c and CD1d are known to traffic to the same intracellular compartments for antigen sampling (13), these CD1c-PM and CD1c-MPM structures did not readily explain how CD1c and CD1d could functionally differentiate. Furthermore, the F′ channel in both CD1c-PM and CD1c-MPM was widely open to solvent, which was strikingly different from known structures of CD1a, CD1b, and CD1d and reminiscent of CD1e (7, 12). Based on these facts we hypothesized that human CD1c might undergo substantial conformational transformations in the F′ channel region upon binding of more optimal ligands, with relevance for T-cell receptor binding.Open in a separate windowFig. S1.Published CD1d-αGC and CD1c-MPM structures show a similar arrangement of their bound ligands in both the A′ and F′ channel. (A) Comparison of the configurations of bound ligands in CD1d-αGC (PDB ID code 1ZT4), CD1c-MPM (PDB ID code 3OV6), and CD1c-SL (PDB ID code 5C9J). (B) Ligands bound to CD1d (PDB ID code 1ZT4) (αGC; shown in yellow) and CD1c (PDB ID code 3OV6) (MPM; shown in blue, and spacer lipid shown in cyan) are superimposed and shown in two different orientations.     

Non-invasive measurement of adrenocortical and gonadal activity in male and female guinea pigs (Cavia aperea f. porcellus)

Taking blood samples is a common method in biomedical and biological research using guinea pigs. However, most blood sampling techniques are complicated and highly invasive and may therefore not be appropriate for certain research topics concerning stress and reproduction. Thus, a non-invasive method to measure steroid hormones is critically needed. The aim of this study was the biological validation of corresponding enzyme immunoassays for the measurement of fecal cortisol, progesterone, estrogen, and testosterone metabolites in guinea pigs. We examined the effect of subcutaneous injections of ACTH or saline on fecal cortisol metabolites to investigate the suitability of fecal samples to monitor adrenocortical activity. Furthermore, we investigated whether fecal sex steroid metabolites accurately reflected endocrine changes observed in plasma samples during female estrous cycles and male puberty, respectively. In addition, we compared fecal testosterone metabolites of intact males, castrated males, and females to investigate the reliability of fecal samples in discriminating gonadal status of males. Concentrations of fecal cortisol metabolites were significantly increased following ACTH challenge, indicating that adrenocortical activity can be monitored via fecal samples. Secondly, in females, plasma and fecal gonadal steroids were significantly correlated in most subjects. The assay for testosterone metabolites, on the other hand, could not clearly discriminate between test groups. From these findings we conclude that fecal samples can be used for the non-invasive assessment of adrenocortical and female reproductive status in guinea pigs. Testosterone metabolism seems to be more complex and further investigations are needed to establish a more suitable assay.