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The liver has a unique ability to regenerate1,2; however, in the setting of acute liver failure (ALF), this regenerative capacity is often overwhelmed, leaving emergency liver transplantation as the only curative option3–5. Here, to advance understanding of human liver regeneration, we use paired single-nucleus RNA sequencing combined with spatial profiling of healthy and ALF explant human livers to generate a single-cell, pan-lineage atlas of human liver regeneration. We uncover a novel ANXA2+ migratory hepatocyte subpopulation, which emerges during human liver regeneration, and a corollary subpopulation in a mouse model of acetaminophen (APAP)-induced liver regeneration. Interrogation of necrotic wound closure and hepatocyte proliferation across multiple timepoints following APAP-induced liver injury in mice demonstrates that wound closure precedes hepatocyte proliferation. Four-dimensional intravital imaging of APAP-induced mouse liver injury identifies motile hepatocytes at the edge of the necrotic area, enabling collective migration of the hepatocyte sheet to effect wound closure. Depletion of hepatocyte ANXA2 reduces hepatocyte growth factor-induced human and mouse hepatocyte migration in vitro, and abrogates necrotic wound closure following APAP-induced mouse liver injury. Together, our work dissects unanticipated aspects of liver regeneration, demonstrating an uncoupling of wound closure and hepatocyte proliferation and uncovering a novel migratory hepatocyte subpopulation that mediates wound closure following liver injury. Therapies designed to promote rapid reconstitution of normal hepatic microarchitecture and reparation of the gut–liver barrier may advance new areas of therapeutic discovery in regenerative medicine.Harnessing single-nucleus RNA sequencing and spatial profiling, this work dissects unanticipated aspects of human liver regeneration to uncover a novel migratory hepatocyte subpopulation mediating wound closure following acute liver injury. [ABSTRACT FROM AUTHOR]

Liver cirrhosis is a major cause of death worldwide and is characterized by extensive fibrosis. There are currently no effective antifibrotic therapies available. To obtain a better understanding of the cellular and molecular mechanisms involved in disease pathogenesis and enable the discovery of therapeutic targets, here we profile the transcriptomes of more than 100,000 single human cells, yielding molecular definitions for non-parenchymal cell types that are found in healthy and cirrhotic human liver. We identify a scar-associated TREM2+CD9+ subpopulation of macrophages, which expands in liver fibrosis, differentiates from circulating monocytes and is pro-fibrogenic. We also define ACKR1+ and PLVAP+ endothelial cells that expand in cirrhosis, are topographically restricted to the fibrotic niche and enhance the transmigration of leucocytes. Multi-lineage modelling of ligand and receptor interactions between the scar-associated macrophages, endothelial cells and PDGFRα+ collagen-producing mesenchymal cells reveals intra-scar activity of several pro-fibrogenic pathways including TNFRSF12A, PDGFR and NOTCH signalling. Our work dissects unanticipated aspects of the cellular and molecular basis of human organ fibrosis at a single-cell level, and provides a conceptual framework for the discovery of rational therapeutic targets in liver cirrhosis. Single-cell RNA sequencing is used to characterize and compare the functional diversity of cells from liver biopsies of human scarred and normal liver, and identifies markers for scar-associated macrophages and endothelial cells. [ABSTRACT FROM AUTHOR]

Activation of cellular transcriptional responses, mediated by hypoxia-inducible factor (HIF), is common in many types of cancer, and generally confers a poor prognosis. Known to induce many hundreds of protein-coding genes, HIF has also recently been shown to be a key regulator of the non-coding transcriptional response. Here, we show that NEAT1 long non-coding RNA (lncRNA) is a direct transcriptional target of HIF in many breast cancer cell lines and in solid tumors. Unlike previously described lncRNAs, NEAT1 is regulated principally by HIF-2 rather than by HIF-1. NEAT1 is a nuclear lncRNA that is an essential structural component of paraspeckles and the hypoxic induction of NEAT1 induces paraspeckle formation in a manner that is dependent upon both NEAT1 and on HIF-2. Paraspeckles are multifunction nuclear structures that sequester transcriptionally active proteins as well as RNA transcripts that have been subjected to adenosine-to-inosine (A-to-I) editing. We show that the nuclear retention of one such transcript, F11R (also known as junctional adhesion molecule 1, JAM1), in hypoxia is dependent upon the hypoxic increase in NEAT1, thereby conferring a novel mechanism of HIF-dependent gene regulation. Induction of NEAT1 in hypoxia also leads to accelerated cellular proliferation, improved clonogenic survival and reduced apoptosis, all of which are hallmarks of increased tumorigenesis. Furthermore, in patients with breast cancer, high tumor NEAT1 expression correlates with poor survival. Taken together, these results indicate a new role for HIF transcriptional pathways in the regulation of nuclear structure and that this contributes to the pro-tumorigenic hypoxia-phenotype in breast cancer. [ABSTRACT FROM AUTHOR]

Geochronology and stratigraphic revision of the Lake Johnston greenstone belt and adjacent granitoids and granitic gneiss provide new insight into the age of komatiites in the Southern Cross Domain of the Archean Yilgarn Craton. Roundtop Komatiites are geochemically similar to undated komatiites in the adjacent Ravensthorpe and Southern Cross—Forrestania greenstone belts, and the results can be extrapolated to improve the regional understanding and geodynamic evolution. Consequently, the further refined knowledge of the regional stratigraphy improves the understanding of the evolution and targeting of komatiite-hosted nickel deposits. A minimum age ofca2773 Ma for the succession of the Lake Johnston greenstone belt is provided by crosscutting granitic rocks, with a maximum age for the underlying Roundtop Komatiite given by a maximum depositional age ofca2876 Ma for felsic volcaniclastic rocks of the underlying Honman Formation. These new results suggest that komatiites of the Southern Cross Domain are significantly younger than previously assumed, which has implications for Yilgarn-wide geodynamic models regarding ‘plume activity’ and global correlations in the Meso- to Neoarchean. [ABSTRACT FROM AUTHOR]

Background:Clear cell renal cancer frequently harbours von Hippel-Lindau (VHL) gene mutations, leading to stabilisation of the hypoxia-inducible factors (HIFs) and expression of their target genes. We investigated HIF-1 and HIF-2 in the regulation of microRNA-210 (miR-210), and its clinical relevance in renal tumours.Methods:RCC4 and 786-O renal cancer cell lines transfected with either an empty vector or functional VHL and incubated in normoxia or hypoxia were examined for miR-210 expression. Hypoxia-inducible factor siRNAs were used to examine their regulation of miR-210. Seventy-one clear cell renal tumours were sequenced for VHL mutations. Expression of miR-210, VHL, CA9, ISCU and Ki-67 were determined by immunohistochemistry and qRT-PCR.Results:In addition to HIF-1 regulating miR-210 in renal cancer, HIF-2 can regulate this microRNA in the absence of HIF-1. MicroRNA-210 is upregulated in renal cancer compared with normal renal cortex tissue. MicroRNA-210 correlates negatively with its gene target ISCU at the protein and mRNA level. MicroRNA-210 correlated with positive outcome variables and negatively with Ki-67.Conclusion:We provide further evidence of miR-210 activity in vivo, and show that high miR-210 expression is associated with better clinico-pathological prognostic factors. [ABSTRACT FROM AUTHOR]

Background: A transcription regulatory complex (TRC) that includes Ets1, Ets2, PEA3 and β-catenin/T-cell factors regulates osteopontin (OPN) that is implicated in colorectal cancer (CRC) dissemination. The consistency of OPN transcriptional control between primary CRC and metastases is unclear. This study investigates expression and prognostic significance of the OPN-TRC in primary human CRC and associated colorectal liver metastases (CRLM).Methods: Osteopontin-TRC factors were assayed by digital microscopy in 38 primary CRCs and matched CRLM specimens and assessed against clinical prognosis.Results: In primary CRC, OPN expression intensity correlated with that of its co-activators, PEA3 (r=0.600; P<0.01), Ets1 (r=0.552; P<0.01), Ets2 (r=0.521; P<0.01) and had prognostic significance. Osteopontin intensity in primary CRC inversely correlated with the interval between diagnosis and resection of CRLM. Overall OPN intensity was lower in CRLM than primary CRC and correlations with co-activators were weaker, for example, Ets1 (P=0.047), PEA3 (P=0.022) or nonsignificant (Ets2). The ratio of OPN expression in CRLM vs primary CRC had prognostic significance.Conclusion: This study supports transcriptional control of OPN by known coregulators in both primary and secondary CRC. Weaker associations in CRLM suggest involvement of other unknown factors possibly from the liver microenvironment or resulting from additional genetic or epigenetic changes that drive tumour metastatic capability in OPN transcriptional control. [ABSTRACT FROM AUTHOR]

Background: Blunt and penetrating liver trauma is common and often presents major diagnostic and management problems. Methods: A literature review was undertaken to determine the current consensus on investigation and management strategies. Results: The liver is the most frequently injured organ following abdominal trauma. Immediate assessment with ultrasound has replaced diagnostic peritoneal lavage in the resuscitation room, but computerised tomography remains the gold standard investigation. Nonoperative management is preferred in stable patients but laparotomy is indicated in unstable patients. Damage control techniques such as perihepatic packing, hepatotomy plus direct suture, and resectional debridement are recommended. Major complex surgical procedures such as anatomical resection or atriocaval shunting are now thought to be redundant in the emergency setting. Packing is also recommended for the inexperienced surgeon to allow control and stabilisation prior to transfer to a tertiary centre. Interventional radiological techniques are becoming more widely used, particularly in patients who are being managed nonoperatively or have been stabilised by perihepatic packing. Conclusions: Management of liver injuries has evolved significantly throughout the last two decades. In the absence of other abdominal injuries, operative management can usually be avoided. Patients with more complex injuries or subsequent complications should be transferred to a specialist centre to optimise final outcome. [ABSTRACT FROM AUTHOR]

Treitz's hernia is the eponymous name for a paraduodenal hernia. These are rare hernias that arise in the potential spaces and folds of the posterior parietal peritoneum adjacent to the ligament of Treitz. Presentation may be acute with small bowel obstruction or bowel ischaemia, or with chronic intermittent abdominal pain. Treatment is by surgery, due to the high (50%) lifetime risk of obstruction. Here, we present two cases from our own institution and review the literature regarding the embryology, anatomy, cross-sectional imaging and surgery of these fascinating hernias. [ABSTRACT FROM AUTHOR]

Treitz’s hernia is the eponymous name for a paraduodenal hernia. These are rare hernias that arise in the potential spaces and folds of the posterior parietal peritoneum adjacent to the ligament of Treitz. Presentation may be acute with small bowel obstruction or bowel ischaemia, or with chronic intermittent abdominal pain. Treatment is by surgery, due to the high (50%) lifetime risk of obstruction. Here, we present two cases from our own institution and review the literature regarding the embryology, anatomy, cross-sectional imaging and surgery of these fascinating hernias. [ABSTRACT FROM AUTHOR]

The article evaluates the mesenteric lymph pathway and the lymph injury proteome in experimental acute pancreatitis (AP)-associated multiple organ failure (MOF). It tests the hypothesis that immunoregulatory tryptophan catabolites contribute to mesenteric lymph cytotoxicity. The results of the study support the concept that mesenteric lymph-borne kynurenines may contribute to pancreatitis-associated MOF.

Background: Reverse total shoulder arthroplasty is currently being used to treat selected patients with disabling shoulder arthropathy. The purposes of this study were to investigate the medium-term results of reverse total shoulder arthroplasty and to analyze the influence of etiology on the result.Methods: We carried out a multicenter study with a minimum follow-up of five years and determined the survival rate of the prosthesis according to the initial etiology of the shoulder arthropathy. Eighty prostheses were implanted in seventy-seven patients between 1992 and 1998. Sixty-six shoulders had an arthropathy with a massive rotator cuff tear, and fourteen shoulders had a disorder with another etiology (rheumatoid arthritis, trauma, or revision arthropathy). At the time of review, eighteen patients had died and two were lost to follow-up. The remaining fifty-seven patients (sixty shoulders) were examined or interviewed by telephone at a mean follow-up of 69.6 months. Cumulative survival curves were generated with replacement of the prosthesis, glenoid loosening, and a functional Constant score of <30 as the end points.Results: The survival rate with replacement of the prosthesis and glenoid loosening as the end points were 91% and 84%, respectively, at 120 months, with shoulders that had arthropathy with a massive rotator cuff tear demonstrating a significantly better result than those that had a disorder with another etiology (p < 0.05). On the other hand, the survival rate with an absolute Constant score of <30 as an end point was 58% at 120 months, with no significant difference with respect to etiology. Two breaks were observed in the survival curves. The first concerned survival until replacement of the prosthesis and occurred at around three years, reflecting early loosening of the prosthesis. The curve then became stable. A second break started at around six years and reflected progressive deterioration of the functional result.Conclusions: Our findings indicate that the reverse total prosthesis should be reserved for the treatment of very disabling shoulder arthropathy with a massive rotator cuff rupture, and it should be used exclusively in patients over seventy years old with low functional demands. [ABSTRACT FROM AUTHOR]

This article describes the prospective validation of a chromatography data system used for quantitative Good Laboratory Practice studies within a contract research organization. An outline of the overall process and the documentation produced to support the data system validation is presented. [ABSTRACT FROM AUTHOR]

Hypoxia-inducible factor (HIF) is central in coordinating many of the transcriptional adaptations to hypoxia. Composed of a heterodimer of α and β subunits, the α subunit is rapidly degraded in normoxia, leading to inactivation of the hypoxic response. Many models for a molecular oxygen sensor regulating this system have been proposed, but an important finding has been the ability to mimic hypoxia by chelation or substitution of iron. A key insight has been the recognition that HIF-α is targeted for degradation by the ubiquitin-proteasome pathway through binding to the von Hippel-Lindau tumour suppressor protein (pVHL), which forms the recognition component of an E3 ubiquitin ligase complex leading to ubiquitylation of HIF-α. Importantly, the classical features of regulation by iron and oxygen availability are reflected in regulation of the HIF-α /p VHL interaction. It has recently been shown that HIF-α undergoes an iron- and oxygen-dependent modification before it can interact with pVHL, and that this results in hydroxylation of at least one prolyl residue (HIF-1α, Pro 564). This modification is catalysed by an enzyme termed HIF-prolyl hydroxylase (HIF-PH), and compatible with all previously described prolyl-4-hydroxylases HIF-PH also requires 2-oxoglutarate as a cosubstrate. The key position of this hydroxylation in the degradation pathway of HIF-α, together with its requirement for molecular dioxygen as a co-substrate, provides the potential for HIF-PH to function directly as a cellular oxygen sensor. However, the ability of these enzyme(s) to account for the full range of physiological regulation displayed by the HIF system remains to be defined. [ABSTRACT FROM AUTHOR]

Hyperbaric oxygen therapy is an effective treatment for more than just diving-related injuries. It has been successfully used for a variety of conditions, including carbon monoxide and cyanide poisoning, refractory wounds, and osteomyelitis. [ABSTRACT FROM AUTHOR]

As a primary care physician, you may be asked to assess the eligibility of a potential diver. A thorough evaluation can help you determine a candidate's physical, mental, and emotional fitness. [ABSTRACT FROM AUTHOR]

Looks into the importance of conducting cross-checking after initial anatomical orientation to reduce perceptual error and improve patient safety during laparoscopic cholecystectomy. Occurrence of bile duct injury at the stage of initial anatomical orientation or preliminary dissection usually due to perceptual error; System of orientation and cross-checking that has been developed to counter the limitations and risks of relying solely on anatomical reliance points in the area of the gall bladder and Calot's triangle; Need to elevate the anatomical orientation process from the automatic, subconscious level to an orally expressed cross-check.

Dissection of the descending aorta post coarctation repair in a patient with Turner's syndrome has rarely been described. A 45-year-old woman with Turner's syndrome had repair of coarctation by resection and interposition graft. Her postoperative course was uneventful. Chest X-ray two months postoperatively showed a hematoma in the proximal descending aorta, and a CT scan confirmed dissection distal to the coarctation repair, which was treated medically. Subsequent CT scanning one year later showed the hematoma resolving with no increase in the diameter of the dissected segment. [ABSTRACT FROM AUTHOR]

Introduction The peptide hormone relaxin (H2-RLN) has a broad range of biological activities including antifibrotic, anti-inflammatory and haemodynamic effects in a range of target tissues. Increased intrahepatic vascular resistance in cirrhosis is due to mechanical factors related to scarring, but also a dynamic component mediated by myofibroblast (MFB) contractility. We hypothesised that H2-RLN could modulate the dynamic attribute of portal hypertension (PHT) via a direct effect on hepatic stellate cell (HSC)-MFB mediated vasoconstriction. Aim To determine whether H2-RLN could target the contractile phenotype of activated HSC-MFBs in vitro, counterbalance the contractile response in vivo in a model of sinusoidal portal hypertension, and explore the mechanisms underlying its portal hypotensive effect. Method Gene expression in culture activated human HSCs was analysed by qRT-PCR and Western blotting. Collagen gel contraction assays were used to assess HSC-MFB contractility. Nitric oxide (NO) production was measured by Griess assay. Cirrhosis and portal hypertension was induced in age matched male Sprague–Dawley rats by 8 weeks bi-weekly i.p. CCl4, before randomisation to treatment with recombinant human H2-RLN or placebo delivered by s.c. osmotic minipump for 72 hrs (n=10 per group). Portal pressure was measured by direct cannulation. Serum H2-RLN levels were quantified by immunoassay. Liver fibrosis was measured after Sirius red staining by calculation of collagen proportionate area by digital image analysis. Finally, systemic arterial and portal pressure was measured simultaneously in groups of cirrhotic and control rats randomised to acute i.v. H2-RLN or placebo. Results Treatment of culture activated HSCs with H2-RLN downregulated expression of the major cytoskeletal protein, alpha-smooth muscle actin (alpha-SMA), in a dose dependent manner. In collagen gel contraction assays, H2-RLN inhibited HSC-MFB contraction, an effect shown by RNA interference to be mediated via RXFP-1 receptor signaling and increased NO production. Rats treated with CCl4 for 8 weeks developed micronodular cirrhosis, splenomegaly and portal hypertension. Treatment with s.c. H2-RLN for 72 h achieved physiologically relevant serum concentrations and decreased portal pressure by 24% (mean 12.8±0.8 mm Hg vs 9.8±0.3 mm Hg; p=0.002), whereas placebo had no significant effect. The observed haemodynamic response was independent of fibrosis regression. Hepatic expression of alpha-SMA and other intermediate filament proteins was markedly inhibited by H2-RLN, while eNOS activity was increased. Infusion of i.v. H2-RLN in cirrhotic rats rapidly depressed portal pressure (mean 28%±6) but not systemic pressure, compared to placebo which had minimal effect on either parameter. Conclusion We demonstrate for the first time that H2-RLN will effectively downregulate MFB contractile filament expression, contractile function and has a portal hypotensive effect in vivo. Our findings support the deployment of H2-RLN in clinical studies of cirrhosis and PHT. [ABSTRACT FROM PUBLISHER]

A letter to the editor is presented in response to an article about the importance of art and skills in evidence-based dentistry, which was previously published in the "British Dental Journal."

Presents an obituary for David J. Stanley, a dental practitioner, who died on March 11, 2003.

A life cycle approach was used to validate a new LC-MS data system for use in GLP/GMP submissions. Acquisition and processing functions were validated, but specific attention was paid to the validation of data migration from legacy systems using the Mac OS platform to the Windows NT platform to meet 21 CFR Part 11 requirements. [ABSTRACT FROM AUTHOR]