SpiDe-Sr: blind super-resolution network for precise cell segmentation and clustering in spatial proteomics imaging

Spatial proteomics elucidates cellular biochemical changes with unprecedented topological level. Imaging mass cytometry (IMC) is a high-dimensional single-cell resolution platform for targeted spatial proteomics. However, the precision of subsequent clinical analysis is constrained by imaging noise and resolution. Here, we propose SpiDe-Sr, a super-resolution network embedded with a denoising module for IMC spatial resolution enhancement. SpiDe-Sr effectively resists noise and improves resolution by 4 times. We demonstrate SpiDe-Sr respectively with cells, mouse and human tissues, resulting 18.95%/27.27%/21.16% increase in peak signal-to-noise ratio and 15.95%/31.63%/15.52% increase in cell extraction accuracy. We further apply SpiDe-Sr to study the tumor microenvironment of a 20-patient clinical breast cancer cohort with 269,556 single cells, and discover the invasion of Gram-negative bacteria is positively correlated with carcinogenesis markers and negatively correlated with immunological markers. Additionally, SpiDe-Sr is also compatible with fluorescence microscopy imaging, suggesting SpiDe-Sr an alternative tool for microscopy image super-resolution.

Proteome signatures of joint toxicity to arsenic (As) and lead (Pb) in human brain organoids with optic vesicles

Arsenic (As) and lead (Pb) are toxins found in the natural surroundings, and the harmful health outcomes caused by the co-exposure of such toxins have become a considerable problem. However, the joint neurotoxicity of As and Pb to neurodevelopment and the underlying mechanisms remain unclear. Pluripotent stem cell-derived human brain organoids are emerging animal model alternatives for understanding neurological-related diseases. Therefore, we utilized brain organoids with optic vesicles (OVB-organoids) to systematically analyze the neurotoxicity of As and Pb. After 24 h of As and/or Pb exposure, hematoxylin-eosin staining revealed that As and Pb exposure could cause disorders in the structure of the ventricular zone and general cell disarrangement in OVB-organoids. Immunostaining displayed that OVB-organoids are more susceptible to As and Pb co-exposure than independent exposure in apoptosis, proliferation, and cell differentiation. Meanwhile, even though As and Pb could both hinder cell proliferation, contrary to Pb, As could induce an increasing proportion of mitotic (G2/M) cells. The proteome landscape of OVB-organoids illustrated that Pb synergized with As in G2/M arrest and the common role of As and Pb in carcinogenesis. Besides, proteomics analyses suggested the consequential role of autophagy and Wnt pathway in the neurotoxicity of As and Pb co-exposure. Overall, our findings provide penetrating insights into the cell cycle, carcinogenesis, autophagy, and Wnt pathway underlying the As and Pb binary exposure scenarios, which could enhance our understanding of the mixture neurotoxicity mechanisms.

Three-dimensional microfluidics with dynamic fluidic perturbation promotes viability and uniformity of human cerebral organoids

Human cerebral organoids (COs), generated from stem cells, are emerging animal alternatives for understanding brain development and neurodegeneration diseases. Long-term growth of COs is currently hindered by the limitation of efficient oxygen infiltration and continuous nutrient supply, leading to general inner hypoxia and cell death at the core region of the organoids. Here, we developed a three-dimensional (3D) microfluidic platform with dynamic fluidic perturbation and oxygen supply. We demonstrated COs cultured in the 3D microfluidic system grew continuously for over 50 days without cell death at the core region. Increased cell proliferation and enhanced cell differentiation were also observed and verified with immunofluorescence staining, proteomics and metabolomics. Time-lapse proteomics from 7 consecutive acquisitions between day 4 and day 30 identified 546 proteins differently expressed accompanying COs growth, which were mainly relevant to nervous system development, in utero embryonic development, brain development and neuron migration. Our 3D microfluidic platform provides potential utility for culturing high-homogeneous human organoids.

SAIF: Label-Free Separation of Circulating Tumor Cells Using a Self-Amplified Inertial Focusing Microfluidic Chip

Circulating tumor cells (CTCs) are rare cells existing in the bloodstream with a relatively low number, which facilitate as a predictor of cancer progression. However, it is difficult to obtain highly purified intact CTCs with desired viability due to their low percentage among blood cells. In this chapter, we demonstrate the detailed steps for the fabrication and application of the novel self-amplified inertial-focused (SAIF) microfluidic chip that enables size-based, high-throughput, label-free separation of CTCs from the patient blood. The SAIF chip introduced in this chapter demonstrates the feasibility of an extremely narrow zigzag channel (with 40 μm channel width) connected with two expansion regions to effectively separate different-sized cells with amplified separation distance.

Sickle-like Inertial Microfluidic System for Online Rare Cell Separation and Tandem Label-Free Quantitative Proteomics (Orcs-Proteomics)

Label-free proteomics with trace clinical samples provides a wealth of actionable insights for personalized medicine. Clinically acquired primary cells, such as circulating tumor cells (CTCs), are usually with low abundance that is prohibitive for conventional label-free proteomics analysis. Here, we present a sickle-like inertial microfluidic system for online rare cell separation and tandem label-free proteomics (namely, Orcs-proteomics). Orcs-proteomics adopts a buffer system with 0.1% N-dodecyl β-d-maltoside (DDM), 1 mM Tris (2-carboxyethyl) phosphine (TCEP), and 2 mM 2-chloroacetamide (CAA) for cell lysis and reductive alkylation. We demonstrate the application of Orcs-proteomics with 293T cells and manage to identify 913, 1563, 2271, and 2770 protein groups with 4, 13, 68, and 119 cells, respectively. We then spike MCF7 cells with white blood cells (WBCs) to simulate the patient's blood sample. Orcs-proteomics identifies more than 2000 protein groups with an average of 61 MCF7 cells. We further recruit two advanced breast cancer patients and collect 5 and 7 CTCs from each patient through minimally invasive blood drawing. Orcs-proteomics manages to identify 973 and 1135 protein groups for each patient. Therefore, Orcs-proteomics empowers rare cells simultaneously to be separated and counted for proteomics and provides technical support for personalized treatment decision making with rare primary patient samples.

Integrated microfluidic single-cell immunoblotting chip enables high-throughput isolation, enrichment and direct protein analysis of circulating tumor cells

Effective capture and analysis of a single circulating tumor cell (CTC) is instrumental for early diagnosis and personalized therapy of tumors. However, due to their extremely low abundance and susceptibility to interference from other cells, high-throughput isolation, enrichment, and single-cell-level functional protein analysis of CTCs within one integrated system remains a major challenge. Herein, we present an integrated multifunctional microfluidic system for highly efficient and label-free CTC isolation, CTC enrichment, and single-cell immunoblotting (ieSCI). The ieSCI-chip is a multilayer microfluidic system that combines an inertia force-based cell sorter with a membrane filter for label-free CTC separation and enrichment and a thin layer of a photoactive polyacrylamide gel with microwell arrays at the bottom of the chamber for single-cell immunoblotting. The ieSCI-chip successfully identified a subgroup of apoptosis-negative (Bax-negative) cells, which traditional bulk analysis did not detect, from cisplatin-treated cells. Furthermore, we demonstrated the clinical application of the ieSCI-chip with blood samples from breast cancer patients for personalized CTC epithelial-to-mesenchymal transition (EMT) analysis. The expression level of a tumor cell marker (EpCAM) can be directly determined in isolated CTCs at the single-cell level, and the therapeutic response to anticancer drugs can be simultaneously monitored. Therefore, the ieSCI-chip provides a promising clinical translational tool for clinical drug response monitoring and personalized regimen development.

Simplified ARCHITECT microfluidic chip through a dual-flip strategy enables stable and versatile tumoroid formation combined with label-free quantitative proteomic analysis

Recent years, microfluidic three-dimensional(3D) tumor culture technique has made great progress in tumor microenvironment simulation and drug screening. Meanwhile, as their functionality and complexity increase, it is more difficult for current chip models to selectively collect specific-layer cells from tumoroids for further analysis. Moreover, a simplified and robust method for tumoroid formation with highly consistent size and repeatable 3D morphology is relatively ncessary. Here, we report an ARCHITECT (ARtificial CHIp for Tumor Enables Confocal Topography observation) chip, through a dual-flip strategy to implement straightforward tumoroid establishment. This platform guarantees stable batch-to-batch tumoroids formation and allows high resolution confocal imaging. Moreover, an initial cell density as low as 65 cells per chamber is efficient to deliver a tumoroid. With this ARCHITECT chip, different-layer cells of interest could be collected from tumoroid for label-free quantitative(LFQ) proteomic analysis. For application demonstration, we mainly verified this platform for lung carcinoma (A549) tumoroid construction and proteomic analysis at out layer. Our data indicate that the out-layer cells of A549 tumoroid show extensively distinct proteomic expressions compared to two-dimensional cultured A549 cells. The up-regulated proteins are mainly related to tumorigenicity, proliferation and metastasis. And the differentially expressed proteins are mainly relevant to lipid metabolism pathway which is essential to tumor progression and proliferation. This platform provides a simplified yet robust technique to connect microfluidic tumoroid construction and LFQ proteomic analysis. The simplicity of this technique should open the way to numerous applications such as discovering the innovative targets for cancer treatment, and studying the mophological and proteomic heterogeneity of different-layer cells across the tumoroid.

Application of Microfluidics in Single-cell Manipulation, Omics and Drug Development

BACKGROUND

Cell heterogeneity exists among different tissues even in the same type of cells. Cell heterogeneity leads to a difference in cell size, functions, biological activity, and for cancer cells it causes different drug responses and resistance. Meanwhile, microfluidics is a promising tool for single-cell research to reveal cell heterogeneity.

METHOD

Through literature research conducted over the past ten years on microfluidics, we summarize and introduce the application of microfluidics in single-cell separation and manipulation, featuring techniques such as acoustic manipulation, optical manipulation, single-cell trapping, and patterning, as well as single-cell omics including single-cell genomics, single-cell transcriptomics, single-cell proteome, single-cell metabolome, and drug development.

RESULTS

Microfluidics is a flexible, precise tool, and it is easy to integrate with different functions. Firstly, it can be used as an important tool to separate rare but important cells according to the cell`s biological or physical properties. Secondly, microfluidics can provide the possibility of single-cell omics. Thirdly, microfluidics can be used in drug development specifically in drug delivery and drug combination. Meanwhile, droplet microfluidics has gradually become the most powerful tool to encapsulate single-cells with other reagents for DNA, RNA, or protein analysis.

CONCLUSION

Microfluidics is a robust platform technology which is able to accomplish rare cell separation, efficient single-cell omics analysis and provide a platform for drug development and drug delivery.

Label-free Separation of Circulating Tumor Cells Using a Self-Amplified Inertial Focusing (SAIF) Microfluidic Chip

Circulating tumor cells (CTCs) are rare cells existing in the bloodstream with a relatively low number, which facilitate as a predictor of cancer progress. However, it is difficult to obtain highly purified intact CTCs with desired viability due to the low percentage of CTCs among blood cells. In this work, we demonstrate a novel self-amplified inertial focused (SAIF) microfluidic chip that enables size-based, high-throughput, label-free separation of CTCs from a patient's blood. The SAIF chip introduced in this study demonstrated the feasibility of an extremely narrow zigzag channel (with 40 μm channel width) connected with two expansion regions to effectively separate different-sized cells with amplified separation distance. The chip performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with three different types of cancer cells. The separation efficiencies for blood cells and spiked cancer cells are higher than 80%. Recovery rates of cancer cells were tested by spiking 1500 lung cancer cells (A549), breast cancer cells (MCF-7), and cervical cancer cells (HeLa) separately to 3 mL 0.09% saline with 3 × 10⁶ white blood cells (WBCs). The recovery rates for larger cells (MCF-7 and HeLa) were 79.1 and 85.4%, respectively. Viabilities of the cells harvested from outlets were all higher than 97% after culturing for 24, 48, and 72 h. The SAIF chip performance was further confirmed using the real clinical patient blood samples from four lung cancer patients. Theoretical force balance analysis in physics, computational simulations, and experimental observations indicate that the SAIF chip is simple but effective, and high-throughput separation CTCs can be readily achieved without complex structures.

How might controlled fusion fit into the emerging low-carbon energy system of the mid-twenty-first century?

We examine the characteristics that fusion-based generation technologies will need to have if they are to compete in the emerging low-carbon energy system of the mid-twenty-first century. It is likely that the majority of future electric energy demand will be provided by the lowest marginal cost energy technology-which in many regions will be stochastically varying renewable solar and wind electric generation coupled to systems that provide up to a few days of energy storage. Firm low-carbon or zero-carbon resources based on gas-fired turbines with carbon capture, advanced fission reactors, hydroelectric and perhaps engineered geothermal systems will then be used to provide the balance of load in a highly dynamic system operating in competitive markets governed by merit-order pricing mechanisms that select the lowest-cost supplies to meet demand. These firm sources will have overnight capital costs in the range of a few $/Watt, be capable of cycling down to a fraction of their maximum power output, operate profitably at low utilization fraction, and have a suitable unit size of order 100 MW_e. If controlled fusion using either magnetic confinement or inertial confinement approaches is to have any chance of providing a material contribution to future electrical energy needs, it must demonstrate these key qualities and at the same time prove robust safety characteristics that avoid the perceived dread risk that plagues nuclear fission power, avoid the generation of long-lived radioactive waste and demonstrate highly reliable operations. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 1)'.

Project IDentif.AI: Harnessing Artificial Intelligence to Rapidly Optimize Combination Therapy Development for Infectious Disease Intervention

In 2019/2020, the emergence of coronavirus disease 2019 (COVID‐19) resulted in rapid increases in infection rates as well as patient mortality. Treatment options addressing COVID‐19 included drug repurposing, investigational therapies such as remdesivir, and vaccine development. Combination therapy based on drug repurposing is among the most widely pursued of these efforts. Multi‐drug regimens are traditionally designed by selecting drugs based on their mechanism of action. This is followed by dose‐finding to achieve drug synergy. This approach is widely‐used for drug development and repurposing. Realizing synergistic combinations, however, is a substantially different outcome compared to globally optimizing combination therapy, which realizes the best possible treatment outcome by a set of candidate therapies and doses toward a disease indication. To address this challenge, the results of Project IDentif.AI (Identifying Infectious Disease Combination Therapy with Artificial Intelligence) are reported. An AI‐based platform is used to interrogate a massive 12 drug/dose parameter space, rapidly identifying actionable combination therapies that optimally inhibit A549 lung cell infection by vesicular stomatitis virus within three days of project start. Importantly, a sevenfold difference in efficacy is observed between the top‐ranked combination being optimally and sub‐optimally dosed, demonstrating the critical importance of ideal drug and dose identification. This platform is disease indication and disease mechanism‐agnostic, and potentially applicable to the systematic N‐of‐1 and population‐wide design of highly efficacious and tolerable clinical regimens. This work also discusses key factors ranging from healthcare economics to global health policy that may serve to drive the broader deployment of this platform to address COVID‐19 and future pandemics.

The effect of therapeutic drug monitoring of beta-lactam and fluoroquinolones on clinical outcome in critically ill patients: the DOLPHIN trial protocol of a multi-centre randomised controlled trial

BACKGROUND

Critically ill patients undergo extensive physiological alterations that will have impact on antibiotic pharmacokinetics. Up to 60% of intensive care unit (ICU) patients meet the pharmacodynamic targets of beta-lactam antibiotics, with only 30% in fluoroquinolones. Not reaching these targets might increase the chance of therapeutic failure, resulting in increased mortality and morbidity, and antibiotic resistance. The DOLPHIN trial was designed to demonstrate the added value of therapeutic drug monitoring (TDM) of beta-lactam and fluoroquinolones in critically ill patients in the ICU.

METHODS

A multi-centre, randomised controlled trial (RCT) was designed to assess the efficacy and cost-effectiveness of model-based TDM of beta-lactam and fluoroquinolones. Four hundred fifty patients will be included within 24 months after start of inclusion. Eligible patients will be randomly allocated to either study group: the intervention group (active TDM) or the control group (non-TDM). In the intervention group dose adjustment of the study antibiotics (cefotaxime, ceftazidime, ceftriaxone, cefuroxime, amoxicillin, amoxicillin with clavulanic acid, flucloxacillin, piperacillin with tazobactam, meropenem, and ciprofloxacin) on day 1, 3, and 5 is performed based upon TDM with a Bayesian model. The primary outcome will be ICU length of stay. Other outcomes amongst all survival, disease severity, safety, quality of life after ICU discharge, and cost effectiveness will be included.

DISCUSSION

No trial has investigated the effect of early TDM of beta-lactam and fluoroquinolones on clinical outcome in critically ill patients. The findings from the DOLPHIN trial will possibly lead to new insights in clinical management of critically ill patients receiving antibiotics. In short, to TDM or not to TDM?

TRIAL REGISTRATION

EudraCT number: 2017-004677-14. Sponsor protocol name: DOLPHIN. Registered 6 March 2018 . Protocol Version 6, Protocol date: 27 November 2019.

Microdroplets-on-chip: A review

Single-cell analysis serves as an important approach to study cell functions and interactions. Catering to the demand of Big Data Era, fast reactions for single cells and paralleled high-throughput analysis have become an urgent need. Microdroplet in microfluidics has advantages of modularity and integrity, as well as high throughput and sensitivity, which present great potential in the field of single-cell analysis. This review is carried out on three aspects to introduce microdroplet chips for single-cell analysis: droplet formation, droplet detection and practical functions. Structures of droplet formation are categorized into three types, including T-shaped channel, flow-involved channel and three-dimensional micro-vortice. The detection methods, including fluorescence, Raman spectroscopy, mass spectroscopy and electrochemical detection, are summarized from applications. Both pros and cons for existing techniques are reviewed and discussed. The functions of microdroplets-on-chip cover cell culture, nucleic acid test and cell identification. For each field, principles/mechanisms and/or schematic images are laconically introduced. Microdroplet in microfluidics has become a major research direction in single-cell analysis. With updated methods of droplet formation such as inertial ordering and micro-vortice, microdroplets-based biochips will expect high throughput detection and high-accuracy trace detection for clinical diagnosis in the near future.

High-Throughput Isolation of Circulating Tumor Cells Using Cascaded Inertial Focusing Microfluidic Channel

Circulating tumor cells (CTCs) are rare cells that detach from a primary or metastasis tumor and flow into the bloodstream. Intact and viable tumor cells are needed for genetic characterization of CTCs, new drug development, and other research. Although separation of CTCs using spiral channel with two outlets has been reported, few literature demonstrated simultaneous isolation of different types of CTCs from human blood using cascaded inertial focusing microfluidic channel. Herein, we introduce a cascaded microfluidic device consisting of two spiral channels and one zigzag channel designed with different fluid fields, including lift force, Dean drag force, and centrifugal force. Both red blood cells (RBCs)-lysed human blood spiked with CTCs and 1:50 diluted human whole blood spiked with CTCs were tested on the presented chip. This chip successfully separated RBCs, white blood cells (WBCs), and two different types of tumor cells (human lung cancer cells (A549) and human breast cancer cells (MCF-7)) simultaneously based on their physical properties. A total of 80.75% of A549 and 73.75% of MCF-7 were faithfully separated from human whole blood. Furthermore, CTCs gathered from outlets could propagate and remained intact. The cell viability of A549 and MCF-7 were 95% and 98%, respectively. The entire separating process for CTCs from blood cells could be finished within 20 min. The cascaded microfluidic device introduced in this study serves as a novel platform for simultaneous isolation of multiple types of CTCs from patient blood.

The Revised Sonographic NASCET Index: A New Hemodynamic Parameter for the Assessment of Internal Carotid Artery Stenosis

PURPOSE

A previously described Doppler parameter, the sonographic NASCET index (SNI), was derived to be more directly analogous to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) methodology for assessing carotid artery stenosis. However, this index does not account for complex changes affecting the Doppler waveform. We propose a revised SNI (rSNI) in an effort to improve predicting carotid stenosis.

MATERIALS AND METHODS

25 carotid bifurcations with stenoses ranging from 40 - 92 % were analyzed. For each vessel, the rSNI and original SNI were calculated. The peak systolic velocity (PSV), rSNI, and original SNI were correlated with angiography using linear regression analysis and relative accuracies were compared at two thresholds.

RESULTS

A correlation between rSNI and angiography was found to be significantly better than that between PSV or internal carotid artery-common carotid artery (ICA-CCA) peak velocity ratio and angiography (r² = 0.47 vs. 0.22; r² = 0.47 vs. 0.16). The accuracy of PSV in predicting high-grade stenosis was 68% and 72%, compared with 80% and 88% for rSNI, at each of two thresholds. The original SNI better correlated with angiography compared to the rSNI (r² = 0.55 vs. 0.47), but with slightly lower accuracy in predicting high-grade stenosis (76% vs. 80%).

CONCLUSION

The revised SNI correlates more closely with angiographic stenosis than either the PSV or the ICA-CCA ratio, and is more accurate in predicting high-grade stenosis. However, it is overall comparable to the original SNI, suggesting that the previously unaccounted for effects over the remainder of the cardiac cycle do not significantly improve the ability to sonographically predict significant stenosis.

Quality of life of children and adolescents with type 1 diabetes in Kuwait

OBJECTIVES

To evaluate the health-related quality of life (HRQoL) of children and adolescents with type 1 diabetes (T1DM) in Kuwait using the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scale and PedsQL 3.0 Diabetes Module, and to identify the risk factors associated with unsatisfactory QoL and their effects on metabolic control.

SUBJECTS AND METHODS

A total of 436 patients (2-18 years) with T1DM (>6 months) and 389 healthy controls, with the parents of both groups, completed the Arabic Generic Core Scale. Those with T1DM also completed the Arabic Diabetes Module.

RESULTS

The mean total score of the PedsQL Diabetes Module was 70.2 ± 9.8 reported by children and 59.9 ± 11.1 reported by parents (higher scores indicate better QoL). Young age and long duration of diabetes were associated with poor QoL (p < 0.001). Boys had better total scores than girls in most age groups (70.3 ± 9.3 vs. 52.3 ± 7.2, p < 0.001); however, girls did better than boys regarding treatment barriers and adherence (71.3 ± 7.8 vs. 68.1 ± 6.2, p < 0.005). Higher HbA1c values were associated with lower QoL scores (31.1 ± 5.1 at HbA1c of 15% vs. 82.5 ± 6.1 at HbA1c of 6%, p < 0.0001).

CONCLUSION

HRQoL of children and adolescents with T1DM was consistently poorer than controls. Parents consistently reported poorer QoL scores than their children. We recommend that more support should be provided for the care of children with diabetes in Kuwait.

P-selectin mediates neutrophil rolling and recruitment in acute pancreatitis

BACKGROUND

The adhesive mechanisms regulating leucocyte-endothelium interactions in the pancreas remain elusive, but selectins may play a role. This study examined the molecular mechanisms mediating leucocyte rolling along the endothelium in the pancreas and the therapeutic potential of targeting the rolling adhesive interaction in acute pancreatitis (AP).

METHODS

Pancreatitis was induced by retrograde infusion of 5 per cent sodium taurocholate into the pancreatic duct, repeated intraperitoneal administration of caerulein (50 µg/kg) or intraperitoneal administration of L-arginine (4 g/kg) in C57BL/6 mice. A control and a monoclonal antibody against P-selectin were administered before and after induction of AP. Serum and tissue were sampled to assess the severity of pancreatitis, and intravital microscopy was used to study leucocyte rolling.

RESULTS

Taurocholate infusion into the pancreatic duct increased the serum level of trypsinogen, trypsinogen activation, pancreatic neutrophil infiltration, macrophage inflammatory protein (MIP) 2 formation and tissue damage. Immunoneutralization of P-selectin decreased the taurocholate-induced increase in serum trypsinogen (median (range) 17·35 (12·20-30·00) versus 1·55 (0·60-15·70) µg/l; P = 0·017), neutrophil accumulation (4·00 (0·75-4·00) versus 0·63 (0-3·25); P = 0·002) and tissue damage, but had no effect on MIP-2 production (14·08 (1·68-33·38) versus 3·70 (0·55-51·80) pg/mg; P = 0·195) or serum trypsinogen activating peptide level (1·10 (0·60-1·60) versus 0·45 (0-1·80) µg/l; P = 0·069). Intravital fluorescence microscopy revealed that anti-P-selectin antibody inhibited leucocyte rolling completely in postcapillary venules of the inflamed pancreas.

CONCLUSION

Inhibition of P-selectin protected against pancreatic tissue injury in experimental pancreatitis. Targeting P-selectin may be an effective strategy to ameliorate inflammation in AP.

Rho-kinase signalling regulates trypsinogen activation and tissue damage in severe acute pancreatitis

BACKGROUND AND PURPOSE

Severe acute pancreatitis (SAP) is characterized by trypsinogen activation, infiltration of leucocytes and tissue necrosis but the intracellular signalling mechanisms regulating organ injury in the pancreas remain elusive. Rho-kinase is a potent regulator of specific cellular processes effecting several pro-inflammatory activities. Herein, we examined the role of Rho-kinase signalling in acute pancreatitis.

EXPERIMENTAL APPROACH

Pancreatitis was induced by infusion of taurocholate into the pancreatic duct in C57BL/6 mice. Animals were treated with a Rho-kinase inhibitor Y-27632 (0.5-5 mg·kg⁻¹) before induction of pancreatitis.

KEY RESULTS

Taurocholate infusion caused a clear-cut increase in blood amylase, pancreatic neutrophil infiltration, acinar cell necrosis and oedema formation in the pancreas. Levels of pancreatic myeloperoxidase (MPO), macrophage inflammatory protein-2 (MIP-2), trypsinogen activation peptide (TAP) and lung MPO were significantly increased, indicating local and systemic disease. Inhibition of Rho-kinase activity dose-dependently protected against pancreatitis. For example, 5 mg·kg⁻¹ Y-27632 reduced acinar cell necrosis, leucocyte infiltration and pancreatic oedema by 90%, 89% and 58%, respectively, as well as tissue levels of MPO by 75% and MIP-2 by 84%. Moreover, Rho-kinase inhibition decreased lung MPO by 75% and blood amylase by 83%. Pancreatitis-induced TAP levels were reduced by 61% in Y-27632-treated mice. Inhibition of Rho-kinase abolished secretagogue-induced activation of trypsinogen in pancreatic acinar cells in vitro.

CONCLUSIONS AND IMPLICATIONS

Our novel data suggest that Rho-kinase signalling plays an important role in acute pancreatitis by regulating trypsinogen activation and subsequent CXC chemokine formation, neutrophil infiltration and tissue injury. Thus, these results indicate that Rho-kinase may constitute a novel target in the management of SAP.

Role of platelets in experimental acute pancreatitis

BACKGROUND

Platelets not only control thrombosis and haemostasis but may also regulate inflammatory processes. Acute pancreatitis (AP) is characterized by changes in both coagulation and proinflammatory activities. The role of platelets in AP is not yet known.

METHODS

AP was induced in C57BL/6 mice by repeated caerulein administration (50 µg/kg intraperitoneally). Mice received a platelet-depleting or control antibody before caerulein challenge. Neutrophil infiltration, myeloperoxidase (MPO) and macrophage inflammatory protein (MIP) 2 levels, acinar cell necrosis and haemorrhage in the pancreas, as well as serum amylase activity, were determined 24 h after caerulein injection. In an alternative model of pancreatitis, L-arginine (4 g/kg intraperitoneally) was given twice with an interval of 1 h and tissue samples were taken after 72 h [Correction added after online publication 29 September 2010: in the preceding sentence, 4 mg/kg was corrected to 4 g/kg].

RESULTS

Caerulein administration increased acinar cell necrosis, neutrophil infiltration, focal haemorrhage and serum amylase levels. Platelet depletion reduced acinar cell necrosis, haemorrhage and serum amylase levels in AP. Depletion of platelets decreased caerulein-induced MPO levels and neutrophil recruitment in the pancreas. Platelet depletion abolished caerulein-induced MIP-2 generation in the pancreas and circulation. The effects of platelet depletion on necrosis, neutrophils and MPO levels were confirmed in L-arginine-induced pancreatitis.

CONCLUSION

Platelets play a crucial role in AP by regulating neutrophil infiltration, most likely mediated by MIP-2 production in the pancreas.

Effect of midazolam, dexamethasone and their combination on the prevention of nausea and vomiting following strabismus repair in children

BACKGROUND

Postoperative nausea and vomiting is a common complication following strabismus surgery. This randomized and double-blind study was designed to evaluate the efficacy of midazolam alone or in combination with dexamethasone in reducing the incidence of postoperative nausea and vomiting in children undergoing strabismus repair.

METHODS

One hundred ASA I children, aged 4-12 yr, scheduled to undergo elective strabismus surgery, were enrolled. No premedication was given. Anaesthesia was induced with sevoflurane, nitrous oxide and oxygen. After induction, fentanyl 2 microg kg-1 and cisatracurium 0.1 mg kg-1 were administered and an endotracheal tube was inserted. After induction of anaesthesia and before start of surgery, patients were randomly allocated into one of four groups of 25 children each to receive placebo, midazolam 50 microg kg-1, dexamethasone 0.5 mg kg-1 or a combination of midazolam 50 microg kg-1 and dexamethasone 0.5 mg kg-1. Episodes of nausea, and retching and vomiting were recorded during the first 24 h after surgery.

RESULTS

The incidence of postoperative nausea was 48%, 32%, 12% and 0% with placebo, dexamethasone, midazolam and the midazolam-dexamethasone combination, respectively. The incidence of vomiting was 52% and 32% with placebo and dexamethasone, respectively; no child vomited with midazolam alone, or with the midazolam-dexamethasone combination.

CONCLUSION

Prophylactic midazolam with or without dexamethasone reduces the incidence of PONV in children undergoing strabismus repair.

U.S. medical students choice of careers and its future impact on health care manpower

During the last 10-15 years, the health care system of this country has faced major challenges, among them, spiraling increases of health care costs, physician manpower maldistribution, excessive production of subspecialists, shortages of primary care physicians (family practice, general internal medicine, and general pediatrics), and lack of access to health care, predominantly among the poor and disadvantaged populations. As a way of shedding light on some of these challenges, the authors conducted a study among junior medical students from the University of Texas Medical School at Houston which focused on some of the factors that might influence medical students' choice of careers. In this article, the authors review the most salient findings for some of the problems that currently plague the health care system of this nation. Certainly, the outcome of this study has important educational and health service delivery implications not only in the United States but abroad as well, particularly among developing nations.

The clinical spectrum of Clostridium sordellii bacteraemia: two case reports and a review of the literature

Clostridium sordellii is rarely associated with disease in humans. Since its first report in 1922 only a few cases of bacteraemia have been reported. This report describes two cases of C sordellii bacteraemia; the oldest and youngest patients reported to date. The first, is a previously well 81 year old woman presented with perianal infection, which was later complicated by thrombosis of the aorta, and the second is a 12 year old boy with epilepsy who presented with an ear infection. These cases are also highlighted to demonstrate the wide spectrum of presentation of sordellii bacteraemia.

Interferon-alpha in chronic hepatitis C infection in dialysis patients

This study assesses the efficacy and adverse effects of interferon-alpha (IFN-alpha) administered at a dosage of 3 million units three times weekly for 1 year in 17 hemodialysis patients with hepatitic C virus (HCV)-associated chronic hepatitis (biopsy proven). The patients were prospectively followed up for a period of 18 months. Liver biopsy was repeated after 6 months of treatment in 13 patients. Patients were classified according to the histological activity index. Biochemical and virological responses were evaluated at the end (end-of-treatment response) and 6 months after completion of therapy (sustained response). HCV RNA became negative in 76% of the patients after 12 weeks of treatment, in 88% after 12 months of treatment, and in 71% of the patients 6 months after completion of therapy. HCV genotype 4 was found in 60% of our population. Alanine aminotransferase (ALT) levels were initially increased in only 6 patients and normalized in 4 of these patients after 12 weeks of therapy, with end-of-treatment and sustained biochemical responses of 83% and 67%, respectively. Of 13 patients who underwent liver biopsies after 6 months of therapy, 11 patients (85%) showed histological improvement. One patient could not tolerate therapy because of marked lethargy and myalgia; the other patients had minor side effects that did not require discontinuation of treatment. Two patients received a cadaveric renal transplant after 1 year of IFN treatment, and they continued to maintain biochemical and virological responses after a follow-up of 17 and 28 months, respectively.

Benign recurrent intrahepatic cholestasis in a Saudi child

We report a case of benign recurrent intrahepatic cholestasis (BRIC) in an 11-year-old Saudi girl who developed three episodes of pruritus and jaundice at the ages of 4, 8, and 9 years. These episodes were almost stereotypic and lasted 5-8 weeks. Although she had elevated liver enzymes and serum bile acids in her blood during the attacks, they returned to normal between attacks. Thorough investigation excluded other causes of liver disease and her recurrent attacks were shortened by cholestyramine therapy. A diagnosis of BRIC should be kept in mind in patients with cholestasis.

Women's advancement in medicine and academia: barriers and future perspectives

Although women made early advancements in the field of medicine during the second half of the 19th century, they were not able to make relevant strides in both medicine and academia until the 1960s. Despite women's recent advancements, obstacles and barriers to their hope of achieving fairness and equality in their professional and academic careers still exist. These practices include professional discrimination, blatant sexism, lack of appropriate mentors, and unfair faculty promotion processes. In this article, we address the most common problems affecting women physicians' advancement in academic medicine. We also focus on the role of mentorship as a relevant and beneficial factor for progress in their medical and academic careers. Finally, we provide a perspective designed to resolve most of the barriers confronting women physicians in their quest for advancement in academic medicine.

Follow-up of HIV western blot indeterminate results

Indeterminate results obtained with the Western blot (WB) confirmatory test on HIV enzyme immunoassay (EIA)-positive samples, constituted 15.6% (444/2849) over a 2.5-year period at the referral laboratory for the Western region at the King Fahd General Hospital, Jeddah. Two hundred and fourteen WB-indeterminate samples were followed up by repeat WB testing of subsequent samples from the same patients over a 3-12 month period. One hundred and forty-two samples (66.4%) gave negative results. Sixty-five samples (30%) remained indeterminate. Only seven samples (3.3%) not initially meeting WHO criteria for positivity turned clear-cut positive, with high EIA readings on follow-up. It was discovered initally that a significant proportion of indeterminates was due to low-grade cross-contamination between samples as a result of aerosol backflow during aspiration in the washing procedure. This was eliminated by rinsing the lines between samples, separating samples with high EIA from those with low EIA, and rerunning indeterminate samples. A reduction of indeterminates from 21% to 8.5% subsequently followed. After this improvement, most of the samples that remained indeterminate had low EIA readings, and few bands of mainly anti-gag (p55, p24 or p18) or anti-pol (p51) antibodies, while the few turning positive all had anti-gp160, in addition to anti-p24 or p55. Interestingly, over the last year and a half of the study, 1.4% of the total samples (21/1506) had repeatedly high EIA readings but were negative by WB. In addition, 16 samples (1.1%) were positive for HIV-2. A separate computer-based system for the storage of data was very helpful in ascertaining proper follow-up of indeterminate WB results.

Hypodermoclysis as a means of rehydration

This article discusses the use of hypodermoclysis, a method of fluid replacement that is little practised by today's physicians and nurses, although it was widely used in the early 1950s. The article reviews the literature on the use of hypodermoclysis as a safe and convenient method of fluid administration, and spotlights some concerns surrounding the use of hypodermoclysis.

Liver transplantation at king fahad national guard hospital riyadh, kingdom of saudi arabia

Liver disease is a major medical problem in the Kingdom of Saudi Arabia and is mostly due to viral hepatitis. Liver transplantation is the only option for patients with end-stage liver disease offering good long-term survival. The first liver transplant at the King Fahad National Guard Hospital was performed in February 1994 and since then, 40 liver transplants have been performed on 37 patients. Immunosuppression consisted of prednisone combined with cyclosporin (Neoral) or FK 506. Maintenance immunosuppression was with the use of cyclosporin or FK 506 as monotherapy. All, but one patient, survived the surgical procedure; there were no cases of primary non-function; acute cellular rejection occurred in 12 patients all of whom responded to steroids. Pneumonia and biliary sepsis occurred in 12 patients each. A total of 10 patients died, with sepsis being the leading cause of death. The overall graft survival was 73%. Donor shortage continues to be a major limiting factor.

Aluminum monitoring for chronic renal failure patients in kuwait

The importance of monitoring serum aluminum (Al) level in patients undergoing long-term hemodialysis (HD) is well known. This study on 94 HD patients from Mubarak Hospital, Kuwait revealed that serum Al level was significantly higher in HD patients on aluminum hydroxide therapy (n = 57) than those not on this treatment (n = 37) (p = 100 ug/L. Analysis of water and dialysis fluid showed Al levels just above the permissible limit, on certain occasions, suggesting the need for regular monitoring of these substances for Al contamination. Patients on HD for longer than five years and those above the age of 50 years had higher serum Al levels. The most important single factor causing elevated serum Al levels in the study patients was aluminum hydroxide therapy, administered orally as a phosphate binder.

Diagnosis and management of heart failure. Canadian Cardiovascular Society

Many of the recommendations presented in this consensus report are summarized in Figure 2. All patients with known or suspected heart failure should undergo a detailed history and physical examination. Other causes for the symptoms and/or clinical signs indicative of heart failure should be excluded. Routine biochemical tests, as well as a standard chest x-ray and ECG, should be performed on all patients with heart failure. Precipitating or aggravating causes of heart failure should be eliminated. Patients with potentially surgically correctable lesions, such as constrictive pericarditis, valvular disease or left ventricular aneurysm, should be referred for cardiological evaluation and the appropriate surgery. Patients with ischemic induced heart failure should be assessed for possible revascularization by either angioplasty or bypass surgery. Pending clinical findings and the degree of systolic or diastolic dysfunction present, determined by noninvasive tests, the panel made recommendations concerning the choice of various therapeutic agents. These clinical guidelines have been developed for practising physicians who manage patients with heart failure. The process by which consensus recommendations were developed by the Canadian Cardiovascular Society was based on the principle that guidelines have the best chance of succeeding if they are developed by those who will be using them. Strategies that ensure physicians are aware of the current guidelines, and that their implementation leads to measurable improvement in the diagnosis and management of patients with heart failure must be developed. Consensus reports represent an ongoing process which is subject to revision when further conclusive evidence is obtained by ongoing and future clinical trials.

Acute renal failure occurring in scleroderma treated with cyclosporin A: a report of three cases

Cyclosporin A, which is a nephrotoxic agent, has been a mainstay antirejection drug in heart, kidney and lung transplant programmes for about 10 yr. Renal transplant physicians have become adept in balancing its powerful immunosuppressive effects with its undoubted potential nephrotoxicity. Here we report three of eight systemic sclerosis (SSc) patients treated with cyclosporin A who developed acute renal failure. Consideration is given to the evidence of benefit from this agent in SSc and to the management of acute hypertensive renal failure in this disease.

Noninvasive identification of left main and triple vessel coronary artery disease: improved accuracy using quantitative analysis of regional myocardial stress distribution and washout of thallium-201

The capabilities of visual and quantitative analysis of stress redistribution thallium-201 scintigrams, exercise electrocardiography and exercise blood pressure response were compared for correct identification of extensive coronary disease, defined as left main or triple vessel coronary artery disease, or both (50% or more luminal diameter coronary narrowing), in 105 consecutive patients with suspected coronary artery disease. Extensive disease was present in 56 patients and the remaining 49 had either less extensive coronary artery disease (n = 34) or normal coronary arteriograms (n = 15). Although exercise blood pressure response, exercise electrocardiography and visual thallium-201 analysis were highly specific (98, 88 and 96%, respectively), they were insensitive for identification of patients with extensive disease (14, 45 and 16%, respectively). Quantitative thallium-201 analysis significantly improved the sensitivity of visual thallium-201 analysis for identification of patients with extensive disease (from 16 to 63%, p less than 0.001) without a significant loss of specificity (96 versus 86%, p = NS). Eighteen (64%) of the 28 patients who were misclassified by visual analysis as having less extensive disease were correctly classified as having extensive disease by virtue of quantitative analysis of regional myocardial thallium-201 washout. When the results of quantitative thallium-201 analysis were combined with those of blood pressure and electrocardiographic response to exercise, the sensitivity and specificity for identification of patients with extensive disease was 86 and 76%, respectively, and the highest overall accuracy (0.82) was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)