The receptor locus for Escherichia coli F4ab/F4ac in the pig maps distal to the MUC4 - LMLN region

Enterotoxigenic Escherichia coli (ETEC) with fimbriae of the F4 family are one of the major causes of diarrhea and death among neonatal and young piglets. Bacteria use the F4 fimbriae to adhere to specific receptors expressed on the surface of the enterocytes. F4 fimbriae exist in three different antigenic variants, F4ab, F4ac, and F4ad, of which F4ac is the most common. Resistance to ETEC F4ab/F4ac adhesion in pigs has been shown to be inherited as an autosomal recessive trait. In previous studies the ETEC F4ab/F4ac receptor locus (F4bcR) was mapped to the q41 region on pig chromosome 13. A polymorphism within an intron of the mucin 4 (MUC4) gene, which is one of the possible candidate genes located in this region, was shown earlier to cosegregate with the F4bcR alleles. Recently, we discovered a Large White boar from a Swiss experimental herd with a recombination between F4bcR and MUC4. A three-generation pedigree including 45 offspring was generated with the aim to use this recombination event to refine the localization of the F4bcR locus. All pigs were phenotyped using the microscopic adhesion test and genotyped for a total of 59 markers. The recombination event was mapped to a 220-kb region between a newly detected SNP in the leishmanolysin-like gene (LMLN g.15920) and SNP ALGA0072075. In this study the six SNPs ALGA0072075, ALGA0106330, MUC13-226, MUC13-813, DIA0000584, and MARC0006918 were in complete linkage disequilibrium with F4bcR. Based on this finding and earlier investigations, we suggest that the locus for F4bcR is located between the LMLN locus and microsatellite S028

Characterisation of five candidate genes within the ETEC F4ab/ac candidate region in pigs

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) that express the F4ab and F4ac fimbriae is a major contributor to diarrhoea outbreaks in the pig breeding industry, infecting both newborn and weaned piglets. Some pigs are resistant to this infection, and susceptibility is inherited as a simple dominant Mendelian trait. Indentifying the genetics behind this trait will greatly benefit pig welfare as well as the pig breeding industry by providing an opportunity to select against genetically susceptible animals, thereby reducing the number of diarrhoea outbreaks. The trait has recently been mapped by haplotype sharing to a 2.5 Mb region on pig chromosome 13, a region containing 18 annotated genes. FINDINGS: The coding regions of five candidate genes for susceptibility to ETEC F4ab/ac infection (TFRC, ACK1, MUC20, MUC4 and KIAA0226), all located in the 2.5 Mb region, were investigated for the presence of possible causative mutations. A total of 34 polymorphisms were identified in either coding regions or their flanking introns. The genotyping data for two of those were found to perfectly match the genotypes at the ETEC F4ab/ac locus, a G to C polymorphism in intron 11 of TFRC and a C to T silent polymorphism in exon 22 of KIAA0226. Transcriptional profiles of the five genes were investigated in a porcine tissue panel including various intestinal tissues. All five genes were expressed in intestinal tissues at different levels but none of the genes were found differentially expressed between ETEC F4ab/ac resistant and ETEC F4ab/ac susceptible animals in any of the tested tissues. CONCLUSIONS: None of the identified polymorphisms are obvious causative mutations for ETEC F4ab/ac susceptibility, as they have no impact on the level of the overall mRNA expression nor predicted to influence the composition of the amino acids composition. However, we cannot exclude that the five tested genes are bona fide candidate genes for susceptibility to ETEC F4ab/ac infection since the identified polymorphism might affect the translational apparatus, alternative splice forms may exist and post translational mechanisms might contribute to disease susceptibility

Urinary secretion and extracellular aggregation of mutant uromodulin isoforms.

Uromodulin is exclusively expressed in the thick ascending limb and is the most abundant protein secreted in urine where it is found in high-molecular-weight polymers. Its biological functions are still elusive, but it is thought to play a protective role against urinary tract infection, calcium oxalate crystal formation, and regulation of water and salt balance in the thick ascending limb. Mutations in uromodulin are responsible for autosomal-dominant kidney diseases characterized by defective urine concentrating ability, hyperuricemia, gout, tubulointerstitial fibrosis, renal cysts, and chronic kidney disease. Previous in vitro studies found retention in the endoplasmic reticulum as a common feature of all uromodulin mutant isoforms. Both in vitro and in vivo we found that mutant isoforms partially escaped retention in the endoplasmic reticulum and reached the plasma membrane where they formed large extracellular aggregates that have a dominant-negative effect on coexpressed wild-type protein. Notably, mutant uromodulin excretion was detected in patients carrying uromodulin mutations. Thus, our results suggest that mutant uromodulin exerts a gain-of-function effect that can be exerted by both intra- and extracellular forms of the protein

Liver resection vs radiofrequency ablation in single hepatocellular carcinoma of posterosuperior segments in elderly patients

Background: Liver resection and radiofrequency ablation are considered curative options for hepatocellular carcinoma. The choice between these techniques is still controversial especially in cases of hepatocellular carcinoma affecting posterosuperior segments in elderly patients. Aim: To compare post-operative outcomes between liver resection and radiofrequency ablation in elderly with single hepatocellular carcinoma located in posterosuperior segments. Methods: A retrospective multicentric study was performed enrolling 77 patients age ≥ 70-years-old with single hepatocellular carcinoma (≤ 30 mm), located in posterosuperior segments (4a, 7, 8). Patients were divided into liver resection and radiofrequency ablation groups and preoperative, peri-operative and long-term outcomes were retrospectively analyzed and compared using a 1:1 propensity score matching. Results: After propensity score matching, twenty-six patients were included in each group. Operative time and overall postoperative complications were higher in the resection group compared to the ablation group (165 min vs 20 min, P < 0.01; 54% vs 19% P = 0.02 respectively). A median hospital stay was significantly longer in the resection group than in the ablation group (7.5 d vs 3 d, P < 0.01). Ninety-day mortality was comparable between the two groups. There were no significant differences between resection and ablation group in terms of overall survival and disease free survival at 1, 3, and 5 years. Conclusion: Radiofrequency ablation in posterosuperior segments in elderly is safe and feasible and ensures a short hospital stay, better quality of life and does not modify the overall and disease-free survival

Neuroacanthocytosis associated with a defect of the 4.1R membrane protein

BACKGROUND: Neuroacanthocytosis (NA) denotes a heterogeneous group of diseases that are characterized by nervous system abnormalities in association with acanthocytosis in the patients' blood. The 4.1R protein of the erythrocyte membrane is critical for the membrane-associated cytoskeleton structure and in central neurons it regulates the stabilization of AMPA receptors on the neuronal surface at the postsynaptic density. We report clinical, biochemical, and genetic features in four patients from four unrelated families with NA in order to explain the cause of morphological abnormalities and the relationship with neurodegenerative processes. CASE PRESENTATION: All patients were characterised by atypical NA with a novel alteration of the erythrocyte membrane: a 4.1R protein deficiency. The 4.1R protein content was significantly lower in patients (3.40 ± 0.42) than in controls (4.41 ± 0.40, P < 0.0001), reflecting weakened interactions of the cytoskeleton with the membrane. In patients IV:1 (RM23), IV:3 (RM15), and IV:6 (RM16) the 4.1 deficiency seemed to affect the horizontal interactions of spectrin and an impairment of the dimer self-association into tetramers was detected. In patient IV:1 (RM16) the 4.1 deficiency seemed to affect the skeletal attachment to membrane and the protein band 3 was partially reduced. CONCLUSION: A decreased expression pattern of the 4.1R protein was observed in the erythrocytes from patients with atypical NA, which might reflect the expression pattern in the central nervous system, especially basal ganglia, and might lead to dysfunction of AMPA-mediated glutamate transmission

Genetic and Clinical Predictors of Age of ESKD in Individuals With Autosomal Dominant Tubulointerstitial Kidney Disease Due to UMOD Mutations

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Performance of the model for end-stage liver disease score for mortality prediction and the potential role of etiology

Bakground &amp; aims Although discrimination of the model for end stage liver disease (MELD) is generally considered acceptable, its calibration is still unclear. In a validation study, we assessed the discrimination and calibration performance of 3 versions of the model: original MELD-TIPS, used to predict survival after transjugular intra-hepatic portosystemic shunt (TIPS); classic MELD-Mayo; MELD-UNOS, used by United Network for Organ Sharing (UNOS). Recalibration and model updating were also explored. Methods 776 patients submitted to elective TIPS (TIPS cohort), and 445 unselected patients (non-TIPS cohort) were included. Three, 6 and 12-month mortality predictions were calculated by the 3 MELD versions: discrimination was assessed by c-statistics and calibration by comparing deciles of predicted and observed risks. Cox and Fine and Grey models were used for recalibration and prognostic analyses. Results Major patient characteristics in TIPS/non-TIPS cohorts were: viral etiology 402/188, alcoholic 185/130, NASH 65/33; mean follow-up± SD 25±9/19±21months; 3-6-12 month mortality were respectively, 57-102-142/31-47-99. C-statistics ranged from 0.66 to 0.72 in TIPS and 0.66 to 0.76 in non-TIPS cohorts across prediction times and scores. A post-hoc analysis revealed worse c-statistics in non-viral cirrhosis with more pronounced and significant worsening in non-TIPS cohort. Calibration was acceptable with MELD-TIPS but largely unsatisfactory with MELD-Mayo and -UNOS whose performance improved much after recalibration. A prognostic analysis showed that age, albumin, and TIPS indication might be used for a MELD updating. Conclusions In this validation study the MELD performance was largely unsatisfactory, particularly in non-viral cirrhosis. MELD recalibration and candidate variables for a MELD updating are proposed. Lay summary While discrimination performance of the Model for End Stage Liver Disease (MELD) is credited to be fair to good, its calibration, the correspondence of observed to predicted mortality, is still unsettled. We found that application of 3 different versions of the MELD in two independent cirrhosis cohorts yielded largely imprecise mortality predictions particularly in non-viral cirrhosis and propose a validated model recalibration. Candidate variables for a MELD updating are proposed