Integrated single-cell transcriptome and T cell receptor profiling reveals defects of T cell exhaustion in pulmonary tuberculosis

Tuberculosis-affected lungs with chronic inflammation harbor abundant immunosuppressive immune cells but the nature of such inflammation is unclear. Dysfunction in T cell exhaustion, while implicated in chronic inflammatory diseases, remains unexplored in tuberculosis. Given that immunotherapy targeting exhaustion checkpoints exacerbates tuberculosis, we speculate that T cell exhaustion is dysfunctional in tuberculosis. Using integrated single-cell RNA sequencing and T cell receptor profiling we reported defects in exhaustion responses within inflamed tuberculosis-affected lungs. Tuberculosis lungs demonstrated significantly reduced levels of exhausted CD8+ T cells and exhibited diminished expression of exhaustion-related transcripts among clonally expanded CD4+ and CD8+ T cells. Additionally, clonal expansion of CD4+ and CD8+ T cells bearing T cell receptors specific for CMV was observed. Expanded CD8+ T cells expressed the cytolytic marker GZMK. Hence, inflamed tuberculosis-affected lungs displayed dysfunction in T cell exhaustion. Our findings likely hold implications for understanding the reactivation of tuberculosis observed in patients undergoing immunotherapy targeting the exhaustion checkpoint.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Single-cell RNA-sequencing reveals heterogeneity and intercellular crosstalk in human tuberculosis lung

Lung inflammation indicated by 18F-labeled fluorodeoxyglucose (FDG) in patients with tuberculosis is associated with disease severity and relapse risk upon treatment completion. We revealed the heterogeneity and intercellular crosstalk in lung tissues with 18F-FDG avidity and adjacent uninvolved tissues from 6 tuberculosis patients by single-cell RNA-sequencing. Tuberculous lungs had an influx of regulatory T cells (Treg), exhausted CD8 T cells, immunosuppressive myeloid cells, conventional DC, plasmacytoid DC, and neutrophils. Immune cells in inflamed lungs showed general up-regulation of ATP synthesis and interferon-mediated signaling. Immunosuppressive myeloid and Treg cells strongly displayed transcriptions of genes related to tuberculosis disease progression. Intensive crosstalk between IL4I1-expressing myeloid cells and Treg cells involving chemokines, costimulatory molecules, and immune checkpoints, some of which are specific in 18F-FDG-avid lungs, were found. Our analysis provides insights into the transcriptomic heterogeneity and cellular crosstalk in pulmonary tuberculosis and guides unveiling cellular and molecular targets for tuberculosis therapy.

A retrospective study on drug survival of biologic among patients with psoriasis seen in tertiary hospital in Johor Malaysia

INTRODUCTION

Limited information exists regarding drug survival of biologics among psoriasis patients in Malaysia. This study aimed to determine the drug survival of biologics in Malaysian psoriasis patients, the reasons for drug discontinuation and to identify the predictor of drug survival.

MATERIALS AND METHODS

A retrospective review of case notes on adult psoriasis patients treated with biologics in Hospital Sultanah Aminah Johor Bahru Malaysia, between January 2006 and December 2020. Drug survival was analysed using the Kaplan-Meier method.

RESULTS

By December 2020, 100 patients with 154 treatment courses of biologics were included in the study. Male to female ratio was 1:1. The mean age at onset was 31.36 ± 11.72 years. Ustekinumab was the most frequently prescribed biologics (39%), followed by adalimumab (29.2%), secukinumab (14.9%), etanercept (13%), and infliximab (3.2%). Overall median drug survival for biologics was 25 months (interquartile range [IQR]= 12.0-.0). The median drug survival for ustekinumab was 35 months (IQR, 12-93); followed by 25 months (IQR, 12.0-), 18 months (IQR, 7-85), 17 months (IQR, 11-43), and 8 months (IQR, 1-10) for secukinumab, adalimumab, etanercept, and infliximab, respectively. The main reason for drug discontinuation was loss of efficacy (26%), inadequate funding (14.3%), loss to follow-up (10.4%), adverse events (4.5%), and patients' request (1.3%).

CONCLUSION

Our study shows ustekinumab has the best long-term drug survival among biologics in Malaysian patients with psoriasis in real-life setting. Further study is required to evaluate the long-term drug survival for newer biologics.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Negative Regulator Nlrc3-like Maintain the Balanced Innate Immune Response During Mycobacterial Infection in Zebrafish

The NOD-like receptors (NLRs) have been shown to be involved in infection and autoinflammatory disease. Previously, we identified a zebrafish NLR, nlrc3-like, required for macrophage homeostasis in the brain under physiological conditions. Here, we found that a deficiency of nlrc3-like leads to decreased bacterial burden at a very early stage of Mycobacterium marinum infection, along with increased production of pro-inflammatory cytokines, such as il-1β and tnf-α. Interestingly, myeloid-lineage specific overexpression of nlrc3-like achieved the opposite effects, suggesting that the impact of nlrc3-like on the host anti-mycobacterial response is mainly due to its expression in the innate immune system. Fluorescence-activated cell sorting (FACS) and subsequent gene expression analysis demonstrated that inflammasome activation-related genes were upregulated in the infected macrophages of nlrc3-like deficient embryos. By disrupting asc, encoding apoptosis-associated speck-like protein containing a CARD, a key component for inflammasome activation, the bacterial burden increased in asc and nlrc3-like double deficient embryos compared with nlrc3-like single deficient embryos, implying the involvement of inflammasome activation in infection control. We also found extensive neutrophil infiltration in the nlrc3-like deficient larvae during infection, which was associated with comparable bacterial burden but increased tissue damage and death at a later stage that could be alleviated by administration of dexamethasone. Our findings uncovered an important role of nlrc3-like in the negative regulation of macrophage inflammasome activation and neutrophil infiltration during mycobacterial infection. This highlights the importance of a balanced innate immune response during mycobacterial infection and provides a potential molecular basis to explain how anti-inflammatory drugs can improve treatment outcomes in TB patients whose infection is accompanied by a hyperinflammatory response.

Meta-analysis of clinical trials comparing triple versus dual antithrombotic therapy on risk reduction of stent thrombosis after percutaneous coronary intervention in atrial fibrillation patients

Background

Coronary artery disease (CAD) is a leading cause of mortality worldwide. Atrial fibrillation (AF) and CAD frequently coexist. Patients with acute coronary syndrome (ACS) requiring percutaneous coronary intervention (PCI) are treated with dual antiplatelet therapy (DAPT) - i.e., aspirin and P2Y12 inhibitor- to prevent stent thrombosis (ST) and recurrent myocardial infarction (MI). Patients with AF and CAD are at risk of stroke. Stroke risk is reduced with oral anticoagulant therapy (warfarin) or one of the direct oral anticoagulant agents (DOACs). Patients treated with triple antithrombotic therapy (TAT)- i.e., DAPT plus oral anticoagulant therapy- suffer higher risk of major or clinically significant bleeding compared with DAT (P2Y12 and DOAC). This appeared to be statistically significant in most but not all of the randomised controlled trials (RCTs). However, it is unclear whether the risk of stent thrombosis/MI might be higher in patients treated with DAT. Previous meta-analyses have yielded conflicting conclusions.

Purpose

To determine the optimum antithrombotic therapy for patients with AF and CAD requiring PCI and/or ACS regarding the incidence of myocardial infarction or stent thrombosis.

Methods

A comprehensive literature search was done identifying all RCTs on the efficacy of antithrombotic therapy in patients with AF and ACS or PCI. A meta-analysis was performed to test the hypothesis that TAT significantly reduces the risk of stent thrombosis (ST) and MI.

Results

A total of 11,542 patients were included in the 5 RCTs, comparing TAT vs DAT – i.e., WOEST Trial 2013 [1], PIONEER AF-PCI 2016 [2], RE-DUAL PCI 2017 [3], ENTRUST-AF PCI 2019 [4], AUGUSTUS 2019 [5]. Triple therapy did not lead to significant reduction in risk of Myocardial Infarction (MI) [risk ratio (RR) 0.85, 95% CI 0.69–1.04, P=0.12], or Stent Thrombosis (RR 0.76, 95% CI 0.51–1.12, P=0.16). [Figure 1] On the other hand, the risk of major bleeding or clinically significant bleeding is significantly lower with DAT [Figure 2].

Conclusion

DAT comprising of warfarin or DOAC and P2Y12 inhibitor reduced risk of major or clinically significant bleeding without increasing the risk of ST or recurrent MI as compared to TAT. The results encourage the use of DAT rather than TAT in patients with ACS and/or patients requiring PCI with AF who require combined antiplatelet and anticoagulant therapy.

Funding Acknowledgement

Type of funding sources: None. Major bleeding risk

Eosinophils are part of the granulocyte response in tuberculosis and promote host resistance in mice

Host resistance to Mycobacterium tuberculosis (Mtb) infection requires the activities of multiple leukocyte subsets, yet the roles of the different innate effector cells during tuberculosis are incompletely understood. Here we uncover an unexpected association between eosinophils and Mtb infection. In humans, eosinophils are decreased in the blood but enriched in resected human tuberculosis lung lesions and autopsy granulomas. An influx of eosinophils is also evident in infected zebrafish, mice, and nonhuman primate granulomas, where they are functionally activated and degranulate. Importantly, using complementary genetic models of eosinophil deficiency, we demonstrate that in mice, eosinophils are required for optimal pulmonary bacterial control and host survival after Mtb infection. Collectively, our findings uncover an unexpected recruitment of eosinophils to the infected lung tissue and a protective role for these cells in the control of Mtb infection in mice.

A220 AN UNEXPECTED CAUSE OF ACUTE JAUNDICE IN A POST-TRANSPLANT PATIENT

Background

Complications post liver transplantation are common. These may include thromboses, primary graft nonfunction, biliary complications, chylothorax, infection, and rejection. Hepaticojejunostomy with Roux-en-Y limb is a common technique for pediatric liver transplantation. Complications of hepaticojejunostomy include small bowel obstruction due to incarceration of the Roux-en-Y limb within an internal hernia. Acquired diaphragmatic hernia has previously been reported in liver transplant patients. Here we present a unique case of acute biliary obstruction secondary to incarceration of a Roux limb within an acquired diaphragmatic hernia.

Aims

To describe a unique case of incarcerated Roux-en-Y limb in a diaphragmatic hernia leading to acute jaundice in a pediatric liver transplant patient.

Methods

Retrospective chart review and case review with the surgical and medical teams.

Results

A 14 month old girl with unresectable hepatoblastoma received a living donor, left lateral segment liver transplant using standard venous reconstruction, microvascular plastics arterial reconstruction, and the recipient common hepatic duct was anastomosed to the donor left hepatic duct. Serial ultrasounds showed persistent intrahepatic duct dilatation with cholestasis. Given the concern of biliary obstruction, 10 days post-transplant, she underwent repeat laparotomy and was found to have a dilated common bile duct with a proximal obstruction. A Roux-en-Y hepaticojejunostomy was performed to establish adequate biliary drainage.

Three months post-transplant she developed lung metastases that required wedge resection and chemotherapy. 7 months post-transplant, while admitted for routine chemotherapy she acutely developed jaundice, pruritus, and transaminitis. Liver ultrasound showed an apparent fluid collection at the cut surface of the liver and biliary dilatation. Extrinsic compression of the biliary tree was suspected, and so a percutaneous biliary drain was placed to drain the collection and decompress the biliary system.

Despite improvement in the transaminitis and cholestasis, several days later, she developed severe abdominal pain and associated grunting respirations. An MRI with MRCP to reassess the previous findings and rule out a new intraabdominal cause for her symptoms was completed and unexpectedly showed herniation of her Roux-en-Y limb into a diaphragmatic hernia. She had urgent diaphragmatic hernia repair with reduction of the incarcerated bowel loop, with resolution of her pain and jaundice.

Conclusions

Post liver transplant Roux-en-Y herniation is uncommon, but can occur with internal hernias and in diaphragmatic hernias. This uncommon complication should be considered for the post liver transplant patient with hepaticojejunostomy in the setting of acute jaundice, particularly if accompanied by acute onset abdominal pain and/or increased work of breathing.

Funding Agencies

None

Long non-coding RNAs ENST00000429730.1 and MSTRG.93125.4 are associated with metabolic activity in tuberculosis lesions of sputum-negative tuberculosis patients

Accurate diagnosis of complete inactivation of tuberculosis lesions is still a challenge with respect to sputum-negative tuberculosis. RNA-sequencing was conducted to uncover potential lncRNA indicators of metabolic activity in tuberculosis lesions. Lung tissues with high metabolic activity and low metabolic activity demonstrated by fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography were collected from five sputum-negative tuberculosis patients for RNA-sequencing. Differentially-expressed mRNAs and lncRNAs were identified. Their correlations were evaluated to construct lncRNA-mRNA co-expression network, in which lncRNAs and mRNAs with high degrees were confirmed by quantitative real-time PCR using samples collected from 11 patients. Prediction efficiencies of lncRNA indicators were assessed by receiver operating characteristic curve analysis. Bioinformatics analysis was performed for potential lncRNAs. 386 mRNAs and 44 lncRNAs were identified to be differentially expressed. Differentially-expressed mRNAs in lncRNA-mRNA co-expression network were significantly associated with fibrillar collagen, platelet-derived growth factor binding, and leukocyte migration involved in inflammatory response. Seven mRNAs (C1QB, CD68, CCL5, CCL19, MMP7, HLA-DMB, and CYBB) and two lncRNAs (ENST00000429730.1 and MSTRG.93125.4) were validated to be significantly up-regulated. The area under the curve of ENST00000429730.1 and MSTRG.93125.4 was 0.750 and 0.813, respectively. Two lncRNAs ENST00000429730.1 and MSTRG.93125.4 might be considered as potential indicators of metabolic activity in tuberculosis lesions for sputum-negative tuberculosis.

Increased Th17 activation and gut microbiota diversity are associated with pembrolizumab-triggered tuberculosis

INTRODUCTION

A hypersensitivity response akin to immune reconstitution inflammatory syndrome (IRIS) has been proposed as a mechanism responsible for anti-PD-1 therapy-induced tuberculosis. IRIS is associated with enhanced activation of IL-17A-expressing CD4 + T cells (Th17). Gut microbiota is thought to be linked to pulmonary inflammation through the gut-lung axis.

MATERIALS AND METHODS

We used ImmuCellAI to investigate the T cell population in lung cancer and tuberculosis samples. Then, we applied flow cytometry to monitor the expression levels of the Th17 cell activation marker CD38 in the peripheral blood of a patient experiencing adverse events, including tuberculosis, in response to pembrolizumab. The gut microbiome was examined by 16S rRNA sequencing to examine the alterations caused by pembrolizumab.

RESULTS

The percentage of Th17 cells was increased in both lung cancer and tuberculosis. FACS analysis showed that pembrolizumab induced substantial CD38 expression in Th17 cells. The patient's fecal samples showed that the diversity of the gut microbiota was significantly increased in response to the pembrolizumab cycle. One enriched genus was Prevotella, which has previously been linked to lung inflammation and Th17 immune activation.

DISCUSSION

The observed Th17 activation in our patient was consistent with a role of Th17-mediated IRIS in pembrolizumab-triggered tuberculosis. Pembrolizumab might trigger airway inflammation with a Th17 phenotype through microbiota interactions in the gut-lung axis.

Zinc transporter SLC39A7 relieves zinc deficiency to suppress alternative macrophage activation and impairment of phagocytosis

Macrophages are key phagocytic cells and play an important role in eliminating external microorganisms and endogenous danger signals. Dysregulation in macrophage functions have been reported in patients with asthma. Zinc homeostasis is critical in maintaining macrophage functions. The solute carrier (SLC) protein SLC39A7, a Zn2+ importer, has recently been linked to asthma. However, the roles of SLC39A7 in macrophage phagocytosis are not well understood. Here we found that phagocytosis efficiency was significantly decreased in SLC39A7-knockdown THP-1 cells, however the phagocytosis capability could be reversed with zinc supplementation. SLC39A7 deficiency skewed macrophages towards alternative activation, as indicated by increased expression of M2 activation marker CD206 and decreased expression of M1 activation marker NOS2. Consistent to this result, SLC39A7-knockdown cells produced reduced amounts of proinflammatory cytokines TNF- and IL-6. Furthermore, the mRNA level of receptor Clec4e previously known to be involved in phagocytosis of BCG was significantly reduced in SLC39A7 knockdown cells. Importantly, all these defects due to SLC39A7 deficiency could be reversed by zinc supplementation. Thus, zinc transporter SLC39A7 provide support for phagocytosis and classical macrophage activation.

Pattern of biopsy-proven renal disease in Sabah: A retrospective cross-sectional study over 3.5 years

OBJECTIVES

To explore the epidemiological and histopathological patterns of glomerular diseases in Sabah.

METHODS

A state-wide cross-sectional study was conducted. There were 336 native renal biopsies in 296 eligible patients from 1st January 2013 to 30th June 2016. All patients aged ≥12 years with sufficient sampling (≥8 glomeruli) for histopathological assessment were included. Graft kidney biopsies, protocol-based biopsies and patients with uncertain demographics were excluded. Demographics of patients, clinical data, laboratory parameters prior to biopsy, and histology findings of renal biopsies were collected from local unit database and recorded into a standardised data collection form. Descriptive statistical analyses were employed and factors associated with Lupus nephritis (LN) were explored using logistic regression.

RESULTS

The mean age during biopsy was 34.53 years (Standard Deviation 0.759). Primary glomerulonephritis (PGN) accounted for 42.6% (126) of all native renal biopsies. The commonest cause of PGN was minimal change disease (38.9%, 49) followed by focal segmental glomerulosclerosis (33.3%, 42) and IgA nephropathy (14.3%, 18). LN is the leading cause for secondary glomerulonephritis (SGN) (87.2%, 136). Younger age (Odds Ratio, OR 0.978; 95% Confidence Interval, 95%CI 0.960, 0.996); female gender (OR 17.53; p<0.001); significant proteinuria (OR 132.0; p<0.001); creatinine level at biopsy (OR 11.26; p=0.004); positive antinuclear antibody (ANA) (OR 46.7; p<0.001); and ANA patterns (OR 8.038; p=0.018) were significant in predicting the odds of having LN.

CONCLUSION

This is the first epidemiology study of glomerular diseases in Sabah. The predominance of LN suggests lower threshold for renal biopsy in patients with suspected glomerular disorders. We have identified significant predictors for early detection and treatment of LN.

A97 TACROLIMUS-ASSOCIATED HEMOLYTIC UREMIC SYNDROME IN A PEDIATRIC LIVER TRANSPLANT RECIPIENT

Background

Tacrolimus associated hemolytic uremic syndrome (HUS) has been reported in renal and pediatric cardiac transplantation. Furthermore, in adults receiving liver transplant, there are reports of multiorgan failure, death, and end stage renal failure secondary to tacrolimus induced HUS [J NEPHROL 2003; 16: 580–585]. Although tacrolimus is commonly used in pediatric liver transplantation, there are no reports of the same entity.

Aims

To describe a case of tacrolimus induced HUS in a pediatric liver transplant patient and subsequent re-initiation of tacrolimus.

Methods

The patient was followed during his hospital admission and after discharge.

Results

An 8-year-old male with Progressive Familial Intrahepatic Cholestasis (PFIC) Type III, diagnosed at age 2, presents for living unrelated donor liver transplantation. He was previously well compensated but began to deteriorate in the months leading up to transplant with rising liver enzymes, ascites, and mild encephalopathy after presumed viral gastroenteritis.

He receives a left lateral segment liver transplantation and is started on tacrolimus immunosuppression post liver transplant as per protocol.

On initiation of tacrolimus, the patient’s hemoglobin trends downward to a trough of 59 g/L four days post transplantation. Concurrently, his haptoglobin is &lt;0.10g/L, total bilirubin peaks at 708 umol/L, creatinine rises to a peak of 71 umol/L, urea peaks at 23.0 mmol/L. Platelets reach a nadir at 27x10^9/L, seven days post transplantation. Direct antibody test was negative, and blood cultures remained negative. Given the constellation of hemolytic anemia, thrombocytopenia, and acute kidney injury following initiation of tacrolimus, a diagnosis of atypical HUS is made.

Tacrolimus is discontinued, intravenous methylprednisolone is started and the patient is switched to cyclosporine immunosuppression. Both the hemolysis and kidney injury resolve gradually.

The patient develops side effects from cyclosporine including hypertension and excessive hair growth. One month post discontinuation of tacrolimus, he is started on sirolimus, while weaning steroids and cyclosporine.

Seven weeks post discontinuation of tacrolimus, he is restarted on tacrolimus and is currently tolerating dual immunosuppression with no signs of HUS recurrence.

Conclusions

Atypical HUS secondary to tacrolimus post liver transplant in children is a rare entity.

In the acute period, discontinuation of tacrolimus is essential to preserve renal function given potentially devastating outcomes seen in adults. Cyclosporine is an alternative immunosuppressive agent used in pediatric solid organ transplantation, although it has also been implicated in causing HUS.

Funding Agencies

None

Isoniazid-induced encephalopathy in an end-stage renal disease patient - A case report and literature review

Patients with end stage renal disease have higher risk of tuberculosis due to lower cell-mediated immunity. Standard regime of anti-tuberculosis contains isoniazid where neurological side effects such as seizure and encephalopathy have been documented. We present a case of isoniazid-induced encephalopathy in a haemodialysis patient. A literature review on isoniazid-induced encephalopathy was done. Recognition of this condition is important as it is reversible with cessation of isoniazid and institution of high dose pyridoxine.

Dynamic ubiquitination determines transcriptional activity of the plant immune coactivator NPR1

Activation of systemic acquired resistance in plants is associated with transcriptome reprogramming induced by the unstable coactivator NPR1. Immune-induced ubiquitination and proteasomal degradation of NPR1 are thought to facilitate continuous delivery of active NPR1 to target promoters, thereby maximising gene expression. Because of this potentially costly sacrificial process, we investigated if ubiquitination of NPR1 plays transcriptional roles prior to its proteasomal turnover. Here we show ubiquitination of NPR1 is a progressive event in which initial modification by a Cullin-RING E3 ligase promotes its chromatin association and expression of target genes. Only when polyubiquitination of NPR1 is enhanced by the E4 ligase, UBE4, it is targeted for proteasomal degradation. Conversely, ubiquitin ligase activities are opposed by UBP6/7, two proteasome-associated deubiquitinases that enhance NPR1 longevity. Thus, immune-induced transcriptome reprogramming requires sequential actions of E3 and E4 ligases balanced by opposing deubiquitinases that fine-tune activity of NPR1 without strict requirement for its sacrificial turnover.

Pathological outcome for Chinese patients with low-risk prostate cancer eligible for active surveillance and undergoing radical prostatectomy: comparison of six different active surveillance protocols

INTRODUCTION

Active surveillance is one of the therapeutic options for the management of patients with low-risk prostate cancer. This study compared the performance of six different active surveillance protocols for prostate cancer in the Chinese population.

METHODS

Patients who underwent radical prostatectomy for prostate cancer from January 1998 to December 2012 at a university teaching hospital in Hong Kong were reviewed. Six active surveillance protocols were applied to the cohort. Statistical analyses were performed to compare the probabilities of missing unfavourable pathological outcome. The sensitivity and specificity of each protocol in identifying low-risk disease were compared.

RESULTS

During the study period, 287 patients were included in the cohort. Depending on different active surveillance protocols used, extracapsular extension, seminal vesicle invasion, pathological T3 disease, and upgrading of Gleason score were present on final pathology in 3.3%-17.1%, 0%-3.3%, 3.3%-19.1%, and 20.6%-34.5% of the patients, respectively. The University of Toronto protocol had a higher rate of extracapsular extension at 17.1% and pathological T3 disease at 19.1% on final pathology than the more stringent protocols from John Hopkins (3.3% extracapsular extension, P=0.05 and 3.3% pathological T3 disease, P=0.03) and Prostate Cancer Research International: Active Surveillance (PRIAS; 8.0% pathological T3 disease, P=0.04). The Royal Marsden protocol had a higher rate of upgrading of Gleason score at 34.5% compared with the more stringent protocol of PRIAS at 20.6% (P=0.04). The specificities in identifying localised disease and low-risk histology among different active surveillance protocols were 59%-98% and 58%-94%, respectively. The John Hopkins active surveillance protocol had the highest specificity in both selecting localised disease (98%) and low-risk histology (94%).

CONCLUSIONS

Active surveillance protocols based on prostate-specific antigen and Gleason score alone or including Gleason score of 3+4 may miss high-risk disease and should be used cautiously. The John Hopkins and PRIAS protocols are highly specific in identifying localised disease and low-risk histology.

Newly diagnosed end stage kidney disease in a single centre in Sabah

AIM

To study the epidemiology, clinical characteristics, vascular access, and the short term survival of ESRD patients initiated on dialysis from Hospital Queen Elizabeth (HQE).

BACKGROUND

The number of patients with ESRD is increasing in Sabah, Malaysia. Most patients present late and some live in remote areas with difficult access to healthcare services. Many therefore present with potentially fatal complications.

METHODS

All the newly confirmed ESRD patients who were initiated on renal replacement therapy (RRT) from 1 January to 31 December 2014 were included. The basic epidemiological and clinical data were collected. They were divided into three groups: Group 1 - those known to the medical service and had been prepared properly for the initiation of RRT; Group 2 - those known to the medical service, but were not prepared for the RRT; Group 3 - those with undiagnosed CKD. Outcome is mainly survival at 3rd, 6th, 9th and 12th month.

RESULTS

There were 249 ESRD patients. 153 (61.4%) were male. The average age was 53.3 (range 12 - 83). The main cause of ESRD was diabetic nephropathy (128 patients, 51.4%). Most patients were started on RRT with a catheter (74.3%), 47 patients (18.9%) with a fistula, and 17 patients (6.8%) with a Tenckhoff catheter. 185 (74.3%) patients were not prepared properly (Group 2 - 66.3%, and Group 3 - 8.0%). The survival for 249 patients were 86.3% at 6 months, 77.9% at 12 months. Group 2 has the worst survival (81.9% at 6 months, 71.1% at 12 months).

CONCLUSIONS

Our data showed that most patients (74.3%) were started on dialysis in an unplanned manner with poor survival. A comprehensive and well-supported predialysis programme is needed.

Eosinophils actively participate in the host response to Mtb infection

Mycobacterium tuberculosis (Mtb) is the leading cause of mortality worldwide due to a single infectious agent. Mtb resides in pulmonary macrophages, neutrophils and phagocytes, which are also key effector cells that limit bacterial growth. The role of other granulocytic phagocytes during Mtb infection is largely unknown. Eosinophils have comparable phagocytic function to neutrophils and an overlapping repertoire of granular contents capable of limiting bacterial growth. Here we characterized eosinophil responses to Mtb in vitro and in vivo. Eosinophils from healthy human donors responded to Mtb in vitro by CD69 up-regulation and CD62L down-regulation. Mtb induced the release of the eosinophil-specific granule proteins EDN and ECP. Mtb exposure resulted in secretion of IL-1a, TNFa, MIP-1a, MIP-1b, and IL-8. These results suggest that Mtb directly affects eosinophil degranulation, and that eosinophils are able to contribute to Mtb-driven inflammation. To investigate whether eosinophils actively participate in the cellular immune response to Mtb in vivo we followed the eosinophilic response after pulmonary Mtb infection in non-human primates. Eosinophils were significantly increased in the BAL fluid of Mtb infected rhesus macaques, providing evidence that eosinophils are being actively recruited to the lung in response to Mtb in vivo. Indeed, when we analyzed Mtb infected lung tissue from patients who had undergone lung resection, eosinophils were enriched in fibrotic TB consolidations, cavity wall and necrotic caseum.

We are currently investigating the biological relevance of the eosinophilic response during Mtb infection in the mouse model.

This work was supported by the intramural research programs of NIAID, NIH.

Association of time to prostate-specific antigen nadir and logarithm of prostate-specific antigen velocity after progression in metastatic prostate cancer with prior primary androgen deprivation therapy

We investigated the association of time to prostate-specific antigen nadir (TTPN) and logarithm of prostate-specific antigen velocity after progression Log(PSAVAP) in metastatic prostate cancer with prior primary androgen deprivation therapy (ADT). All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN: TTPN of <3 months, 3–17 months, and >17 months. We compared the Log(PSAVAP) between the different TTPN groups using Mann–Whitney U-test and Kruskal–Wallis test. Further multiple linear regression analyses on Log(PSAVAP) were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months. Longer TTPN was associated with lower Log(PSAVAP) (P = 0.008) within all subgroup analyses (TTPN of <3 vs 3–17 months, P = 0.020; TTPN of 3–17 vs >17 months, P = 0.009; and TTPN of <3 vs >17 months, P = 0.001). Upon multiple linear regression analyses, baseline PSA (regression coefficient 0.001, P = 0.045), PSA nadir (regression coefficient 0.002, P = 0.040), and TTPN (regression coefficient −0.030, P = 0.001) were the three factors that were significantly associated with Log(PSAVAP). In conclusion, a longer TTPN was associated with lower Log(PSAVAP) in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log(PSAVAP). TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression.

The mitosis-specific marker phosphohistone-H3 (PHH3) is an independent prognosticator in uterine smooth muscle tumours: an outcome-based study

AIMS

Accurate mitosis counting, which is important in the diagnosis of uterine smooth muscle tumours (USMTs), is often difficult and subjective. The mitosis-specific immunohistochemical marker phosphohistone-H3 (PHH3) has been shown to be diagnostically useful, but its expression, in relation to outcome, has not been thoroughly investigated. The aim of this study is to evaluate PHH3 as a diagnostic and prognostic marker in USMTs.

METHODS AND RESULTS

PHH3 expression was evaluated in 55 leiomyosarcomas (LMSs), 26 smooth muscle tumours of uncertain malignant potential (STUMPs), 18 leiomyomas with bizarre nuclei (LBN), and 12 leiomyomas (LMs). Scores were expressed as counts per 10 high-power fields (HPFs). Median follow-up durations of patients with LMS, STUMP, LBN and LM were, respectively, 39, 78, 65.5 and 49.5 months. Twenty-eight patients with LMSs (50.9%) died, and two (7.7%) patients with STUMPs experienced recurrence. The median PHH3 scores for LMSs were significantly higher than those for other categories of tumour. A score of ≥29/10 HPFs was also independently associated with a poor outcome. To test whether the PHH3 score could distinguish between benign USMTs with atypical histology and those that were clinically malignant, two biological groups were further delineated. Patients in group 1 (18 LBNs and 24 STUMPs) all had an uneventful outcome, whereas patients in group 2 (two recurrent STUMPs and 32 LMSs) all had a recurrence or tumour-related death. Median PHH3 scores for the two groups were, respectively, 2/10 HPFs and 27/10 HPFs. A PHH3 score of ≥7/10 HPFs was highly associated with malignancy.

CONCLUSION

PHH3 is useful in evaluation of the biological behaviour of USMTs, and may serve as a prognostic indicator for LMSs.

Separable roles for Mycobacterium tuberculosis ESX-3 effectors in iron acquisition and virulence

Mycobacterium tuberculosis (Mtb) encodes five type VII secretion systems (T7SS), designated ESX-1-ESX-5, that are critical for growth and pathogenesis. The best characterized is ESX-1, which profoundly impacts host cell interactions. In contrast, the ESX-3 T7SS is implicated in metal homeostasis, but efforts to define its function have been limited by an inability to recover deletion mutants. We overcame this impediment using medium supplemented with various iron complexes to recover mutants with deletions encompassing select genes within esx-3 or the entire operon. The esx-3 mutants were defective in uptake of siderophore-bound iron and dramatically accumulated cell-associated mycobactin siderophores. Proteomic analyses of culture filtrate revealed that secretion of EsxG and EsxH was codependent and that EsxG-EsxH also facilitated secretion of several members of the proline-glutamic acid (PE) and proline-proline-glutamic acid (PPE) protein families (named for conserved PE and PPE N-terminal motifs). Substrates that depended on EsxG-EsxH for secretion included PE5, encoded within the esx-3 locus, and the evolutionarily related PE15-PPE20 encoded outside the esx-3 locus. In vivo characterization of the mutants unexpectedly showed that the ESX-3 secretion system plays both iron-dependent and -independent roles in Mtb pathogenesis. PE5-PPE4 was found to be critical for the siderophore-mediated iron-acquisition functions of ESX-3. The importance of this iron-acquisition function was dependent upon host genotype, suggesting a role for ESX-3 secretion in counteracting host defense mechanisms that restrict iron availability. Further, we demonstrate that the ESX-3 T7SS secretes certain effectors that are important for iron uptake while additional secreted effectors modulate virulence in an iron-independent fashion.

Impact of skeletal-related events on survival in patients with metastatic prostate cancer prescribed androgen deprivation therapy

OBJECTIVE

To investigate the impact of skeletal-related events on survival in patients with metastatic prostate cancer prescribed long-term androgen deprivation therapy.

METHODS

This historical cohort study was conducted in two hospitals in Hong Kong. Patients who were diagnosed with metastatic prostate cancer and prescribed androgen deprivation therapy between January 2006 and December 2011 were included. Details of skeletal-related events and mortality were examined.

RESULTS

The median follow-up was 28 (range, 1-97) months. Of 119 patients, 52 (43.7%) developed skeletal-related events throughout the study, and the majority received bone irradiation for pain control. The median actuarial overall survival and cancer-specific survival for patients with skeletal-related events were significantly shorter than those without skeletal-related events (23 vs 48 months, P=0.003 and 26 vs 97 months, P<0.001, respectively). Multivariate analysis revealed that the adjusted hazard ratio of presence of skeletal-related events on overall and cancer-specific survival was 2.73 (95% confidence interval, 1.46-5.10; P=0.002) and 3.92 (95% confidence interval, 1.87-8.23; P<0.001), respectively. A prostate-specific antigen nadir of >4 ng/mL was an independent poor prognostic factor for overall and cancer-specific survival after development of skeletal-related events (hazard ratio=10.42; 95% confidence interval, 2.10-51.66 and hazard ratio=10.54; 95% confidence interval, 1.94-57.28, respectively).

CONCLUSIONS

Skeletal-related events were common in men with metastatic prostate cancer. This is the first reported study to show that a skeletal-related event is an independent prognostic factor in overall and cancer-specific survival in patients with metastatic prostate cancer prescribed androgen deprivation therapy. A prostate-specific antigen nadir of >4 ng/mL is an independent poor prognostic factor for overall and cancer-specific survival following development of skeletal-related events.

Minimally invasive enteroscopically guided small bowel resection

Localisation of small bowel pathology is often difficult, especially intramural small bowel lesions. Even with the use of laparoscopy, visualisation of small bowel lesion is not always possible. The most accurate method to identify such a lesion is by laparotomy with direct visualisation and palpation of the lesion. However, the recent trend in surgical development aims for minimally invasive procedures while keeping the excision of surgical pathology safe and complete, with less surgical trauma. This report illustrates a case of minimally invasive enteroscopically guided small bowel resection.

Survival outcomes of Chinese metastatic prostate cancer patients following primary androgen deprivation therapy in relation to prostate-specific antigen nadir level

AIM

To evaluate the progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS) of Chinese metastatic prostate cancer patients following primary androgen deprivation therapy (ADT) in relation to prostate-specific antigen (PSA) nadir level.

METHODS

All Chinese prostate cancer patients with bone metastases who were treated with primary ADT from 2000 to 2009 were included. Patients' and disease characteristics were recorded. Patients were categorized into two PSA nadir groups (≤1.0 and >1.0 ng/mL). Associations of PSA nadir with PFS, CSS and OS were analyzed with Kaplan-Meier and Cox regression analyses. The survival outcomes of the two PSA nadir groups were presented.

RESULTS

Four hundred nineteen patients were included in the study. PSA nadir appeared to be a good predictor for PFS (hazard ratio [HR] 1.86, 95% confidence interval [CI] 1.35-2.56, P < 0.001), CSS (HR 1.60, 95% CI 0.98-2.64, P = 0.063) and OS (HR 1.77, 95% CI 1.20-2.41, P < 0.001) upon multivariate Cox regression analyses. In the PSA nadir groups of ≤1.0 and >1.0 ng/mL, the median PFS were 15 and 10 months, and the 1-year PFS rates were 64% and 40%, respectively; the median CSS were 42 and 27 months, and the 5-year OS rates were 53% and 28%, respectively; and the median OS were 41 and 24 months, and the 5-year OS rates were 45% and 19%, respectively.

CONCLUSIONS

Higher PSA nadir was associated with shorter PFS, CSS and OS in Chinese metastatic prostate cancer patients following primary ADT. The survival outcomes may serve as references in deciding the best treatment strategy in Chinese prostate cancer patients.

Inhibition of breast cancer resistance protein (ABCG2) in human myeloid dendritic cells induces potent tolerogenic functions during LPS stimulation

Breast cancer resistance protein (ABCG2), a member of the ATP-binding cassette transporters has been identified as a major determinant of multidrug resistance (MDR) in cancer cells, but ABC transporter inhibition has limited therapeutic value in vivo. In this research, we demonstrated that inhibition of efflux transporters ABCG2 induced the generation of tolerogenic DCs from human peripheral blood myeloid DCs (mDCs). ABCG2 expression was present in mDCs and was further increased by LPS stimulation. Treatment of CD1c⁺ mDCs with an ABCG2 inhibitor, Ko143, during LPS stimulation caused increased production of IL-10 and decreased production of pro-inflammatory cytokines and decreased expression of CD83 and CD86. Moreover, inhibition of ABCG2 in monocyte-derived DCs (MDDCs) abrogated the up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in these cells in response to LPS. Furthermore, CD1c⁺ mDCs stimulated with LPS plus Ko143 inhibited the proliferation of allogeneic and superantigen-specific syngenic CD4⁺ T cells and promoted expansion of CD25⁺FOXP3⁺ regulatory T (Treg) cells in an IL-10-dependent fashion. These tolerogenic effects of ABCG2 inhibition could be abolished by ERK inhibition. Thus, we demonstrated that inhibition of ABCG2 in LPS-stimulated mDCs can potently induce tolerogenic potentials in these cells, providing crucial new information that could lead to development of better strategies to combat MDR cancer.

Fucoidan can function as an adjuvant in vivo to enhance dendritic cell maturation and function and promote antigen-specific T cell immune responses

Fucoidan, a sulfated polysaccharide purified from brown algae, has a variety of immune-modulation effects, including promoting antigen uptake and enhancing anti-viral and anti-tumor effects. However, the effect of fucoidan in vivo, especially its adjuvant effect on in vivo anti-tumor immune responses, was not fully investigated. In this study, we investigated the effect of fucoidan on the function of spleen dendritic cells (DCs) and its adjuvant effect in vivo. Systemic administration of fucoidan induced up-regulation of CD40, CD80 and CD86 expression and production of IL-6, IL-12 and TNF-α in spleen cDCs. Fucoidan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in an IL-12-dependent manner. When used as an adjuvant in vivo with ovalbumin (OVA) antigen, fucoidan promoted OVA-specific antibody production and primed IFN-γ production in OVA-specific T cells. Moreover, fucoidan enhanced OVA-induced up-regulation of MHC class I and II on spleen cDCs and strongly prompted the proliferation of OVA-specific CD4 and CD8 T cells. Finally, OVA immunization with fucoidan as adjuvant protected mice from the challenge with B16-OVA tumor cells. Taken together, these results suggest that fucoidan can function as an adjuvant to induce Th1 immune response and CTL activation, which may be useful in tumor vaccine development.

Comparison of plasmid DNA versus PCR amplified gene of insert DNA for nucleofection in Kasumi-1 cells

Plasmid electroporation, or its optimized version nucleofection, is an important technique for gene transfection of cells in suspension. However, substantial cell death and/or low transfection efficiency are still common for some cell lines. By using enhanced green fluorescent protein (EGFP) as a reporter, we compared the use of PCR amplified EGFP (PaEGFP) and its parental plasmid (pEGFP-N2) for nucleofection in Kasumi-1 cells. We found that PaEGFP induced significantly lower cell death but had similar transfection efficiency compared to its parent plasmid (pEGFP-N2). Most importantly, contrary to the pEGFP-N2-nucleofected cells, the PaEGFP-nucleofected cells subsequently grew properly. Tests in other cell lines also implied that PaEGFP indeed induced consistently less cell death, but transfection efficiencies varied, being good in suspension cell lines but lower in adhesive cell lines. We suggest that direct transfection with PCR amplified genes can be a simple and useful approach for optimization of electropulse-based transfection not only of Kasumi-1 cells, but also may be useful for other cell lines that are difficult to transfect in suspension.

How can the R.E.N.A.L. nephrometry scoring system aid management of a solid renal mass?

OBJECTIVES. To investigate use of the R.E.N.A.L. nephrometry score in relation to the choice of treatment and postoperative complications for renal masses. DESIGN. Case series. SETTING. A tertiary referral hospital in Hong Kong. PATIENTS. Data of patients undergoing nephrectomy were collected retrospectively from a clinical database and analysed. A R.E.N.A.L. nephrometry score was allocated to each renal tumour by a blinded qualified radiologist, utilising computerised imaging systems. Patient demographics, choice of surgery (radical vs partial), and approaches (open vs minimally invasive) were analysed with respect to their R.E.N.A.L. score. RESULTS. In all, 74 patients were included during the study period, of which 38 underwent partial nephrectomy and 36 underwent radical nephrectomy. No differences between the groups were found with respect to patient demographics. There were significant differences between the partial and radical nephrectomy groups in terms of their mean nephrometry score (6.9 vs 9.3, P<0.001). The mean nephrometry sum was also significantly different in the open approach versus the minimally invasive approach in patients having partial nephrectomy (7.8 vs 6.0, P=0.001). There was no difference in the postoperative 90-day morbidity and mortality in the partial nephrectomy and radical nephrectomy groups. CONCLUSIONS. The R.E.N.A.L. nephrometry score of a renal mass correlated significantly with our choice of surgery (partial vs radical) and our approach to surgery (open vs minimally invasive surgery), particularly in the partial nephrectomy group. It does not, however, correlate with postoperative complications. The nephrometry score provides a useful tool for objectively describing renal mass characteristics and enhancing better communication for the operative planning directed at renal masses.

Melioidosis and peritoneal dialysis related peritonitis

We report a case of melioidosis presenting as peritonitis in a patient on continuous ambulatory peritoneal dialysis (CAPD). A 47-year-old man, a lorry driver, with end-stage renal disease due to diabetes mellitus on CAPD presented in PD-related peritonitis. He was started on intraperitoneal cloxacillin and ceftazidime, and changed to intraperitoneal vancomycin and meropenam after day 5 due to nonresponse. Burkholderia pseudomallei was identified from the dialysate culture. He was treated with intraperitoneal meropenam for two weeks, and IV ceftazidime for 4 weeks. He responded, and the Tenckhoff catheter was not removed. He was discharged well and continued on oral sulfamethoxazole/trimethoprim for six months. This patient had done his PD exchanges in a lorry.

Mycobacterium tuberculosis exploits human interferon γ to stimulate macrophage extracellular trap formation and necrosis

Human neutrophils form extracellular traps during M. tuberculosis infection, but a similar phenomenon has not been reported in human macrophages. Here we demonstrate that M. tuberculosis induces release of extracellular traps from human macrophages. This process is regulated by elastase activity, previously shown to regulate formation of extracellular traps by neutrophils. Interestingly, formation of extracellular traps by macrophages during M. tuberculosis infection is inducible by interferon γ (IFN-γ). These traps are mainly produced by heavily infected macrophages. Accordingly, IFN-γ is found to stimulate M. tuberculosis aggregation in macrophages. Both IFN-γ–inducible events, extracellular trap formation and mycobacterial aggregation, require the ESX-1 secretion system. In addition, IFN-γ is found to enhance ESX-1–mediated macrophage necrosis. In the absence of ESX-1, IFN-γ does not restore any extracellular trap formation, mycobacterial aggregation, or macrophage necrosis. Thus, initial characterization of macrophage extracellular trap formation due to M. tuberculosis infection led to the uncovering of a novel role for IFN-γ in amplifying multiple effects of the mycobacterial ESX-1.

Quality of diabetes care in public primary care clinics in Hong Kong

BACKGROUND

Little is known about the quality of care for patients with Type 2 diabetes in primary care setting in Hong Kong.

OBJECTIVES

To investigate the quality of care for patients with Type 2 diabetes in Hong Kong primary care setting and potential disparities by patient characteristics and clinics.

METHODS

Cross-sectional study in three general outpatient clinics (GOPCs; public primary care clinics) in Hong Kong involving 1970 patients. Main outcome measures were achievement rates of seven process measures and three intermediate outcome targets and adjusted odds ratios of age, sex, socio-economic status and clinic on the quality measures.

RESULTS

The achievement rates for the recording of HbA1c, blood pressure (BP), cholesterol, body mass index, smoking status, nephropathy screening and retinopathy screening in the previous 12 months were 92.8%, 99.9%, 91.0%, 47.9%, 91.3%, 69.0% and 38.0%, respectively. A total of 58.0%, 38.2% and 36.4% of patients achieved the glycaemic, BP and cholesterol targets, respectively. Older patients were less likely to have records of process measures and more likely to achieve the HbA1c target. Women were less likely to have smoking status recorded and to achieve the HbA1c target. Patients of lower socio-economic status were less likely to have records of process measures and to achieve the BP target. Family medicine training practices had better achievements of the quality measures.

CONCLUSIONS

There is scope for improvement in the quality of diabetes care in the GOPCs. Variations in the quality of care were observed. Family medicine training may enhance the health care quality.

Prevalence of undiagnosed diabetes mellitus and cardiovascular risk factors in Hong Kong professional drivers

AIMS

To investigate the prevalence of undiagnosed diabetes mellitus (DM) and cardiovascular risk factors among professional drivers in Hong Kong.

METHODS

Chinese professional drivers with no history of DM were invited to complete a questionnaire on their health status, followed by taking their body measurements, fasting blood glucose (FG) and lipids. 75g OGTT were performed when FG≥5.6 to <7.0mmol/L.

RESULTS

Of these 3376 drivers (male 92.6%, mean age 50.9±7.6 years), the prevalence of undiagnosed DM, prediabetes, and metabolic syndrome was 8.1% (272/3376, 95% CI 7.1-9.0%), 10.0% (337/3376, 95% CI 9.0-11.0%) and 26.8% (904/3376, 95% CI 25.3-28.3%) respectively, while the corresponding WHO Standard Population age-standardized prevalence was 7.8%, 9.0% and 24.7% respectively. Many of them were obese (51.2%), had hypertension (57.0%) and high cholesterol (58.7%), and a third had hypertriglyceridaemia (34.9%) and low HDL-cholesterol (29.3%). Their median working hours were 60.0 (IQR 14)h. Majority had exercise <1h/week (56.0%) and ate out ≥6times/week (54.9%).

CONCLUSIONS

Hong Kong professional drivers have higher prevalence of undiagnosed DM, cardiovascular risk factors and metabolic syndrome than the general population. Therefore, health care measures targeting against them should be taken to prevent and detect DM and cardiovascular diseases.

Effects of microstructure on flow properties of fibrous porous media at moderate Reynolds number

In this study, effects of microstructure on the viscous permeability and Forchheimer coefficient of monodispersed fibers are investigated. The porous material is represented by a unit cell which is assumed to be repeated throughout the medium. Based on the orientation of the fibers in the space, fibrous media are divided into three categories: one-, two-, and three-directional (1D, 2D, and 3D) structures. Parallel and transverse flow through square arrangements of 1D fibers, simple 2D mats, and 3D simple cubic structures are solved numerically over a wide range of porosity (0.35 < ε < 0.95) and Reynolds number (0.01 < Re < 200). The results are used to calculate the permeability and the inertial coefficient of the considered geometries. An experimental study is performed; the flow coefficients of three different ordered tube banks in the moderate range of Reynolds number (0.001 < Re < 15) are determined. The numerical results are successfully compared with the present and the existing experimental data in the literature. The results suggest that the permeability and Forchheimer coefficient are functions of porosity and fiber orientation. A comparison of the experimental and numerical results with the Ergun equation reveals that this equation is not suitable for highly porous materials. As such, accurate correlations are proposed for determining the Forchheimer coefficient in fibrous porous media.

Critical role for NLRP3 in necrotic death triggered by Mycobacterium tuberculosis

Induction of necrotic death in macrophages is a primary virulence determinant of Mycobacterium tuberculosis. The ESX-1 secretion system and its substrate ESAT-6 are required for M. tuberculosis to induce necrosis, but host factors that mediate the ESAT-6-promoted necrosis remain unknown. Here we report that ESAT-6-promoted necrotic death in THP-1 human macrophages is dependent on the NLRP3 inflammasome, as shown by RNA interference and pharmacological inhibitions. Phagosomes containing ESAT-6-expressing M. tuberculosis recruit markers previously associated with damaged phagosomal membrane, such as galectin-3 and ubiquitinated protein aggregates. In addition, ESAT-6 promoted lysosomal permeabilization by M. tuberculosis. ESAT-6 mutants defective for ubiquitination were unable to trigger NLRP3 activation and necrotic death. Furthermore, Syk tyrosine kinase, recently implicated in NLRP3 activation during fungal and malarial infections, was necessary for mediating the ESAT-6-promoted necrosis and NLRP3 activation. Our results thus link phagosomal damage and Syk activity to NLRP3-mediated necrotic death triggered by M. tuberculosis ESAT-6 during infection.

Scaffold proteins IRSp53 and spinophilin regulate localized Rac activation by T-lymphocyte invasion and metastasis protein 1 (TIAM1)

The Rac exchange factor Tiam1 is involved in diverse cell functions and signaling pathways through multiple protein interactions, raising the question of how signaling and functional specificity are achieved. We have shown that Tiam1 interactions with different scaffold proteins activate different Rac-dependent pathways by recruiting specific Rac effector proteins, and reasoned that there must be regulatory mechanisms governing each interaction. Fibroblasts express at least two Tiam1-interacting proteins, insulin receptor substrate protein 53 kDa (IRSp53) and spinophilin. We used fluorescent resonance energy transfer (FRET) to measure localized Rac activation associated with IRSp53 and spinophilin complexes in individual fibroblasts to test this hypothesis. Pervanadate or platelet-derived growth factor induced localized Rac activation dependent on Tiam1 and IRSp53. Forskolin or epinephrine induced localized Rac activation dependent on Tiam1 and spinophilin. In spinophilin-deficient cells, Tiam1 co-localized with IRSp53 in response to pervanadate or platelet-derived growth factor. In IRSp53-deficient cells, Tiam1 co-localized with spinophilin in response to forskolin or epinephrine. Total cellular levels of activated Rac were affected only in cells with exogenous Tiam1, and were primarily increased in the membrane fraction. Downstream effects of Rac activation were also stimulus and scaffold-specific. Cell ruffling, spreading, and cell adhesion were dependent on IRSp53, but not spinophilin. Epinephrine decreased IRSp53-dependent adhesion and increased cell migration in a Rac and spinophilin-dependent fashion. These results support the idea that Tiam1 interactions with different scaffold proteins couple distinct upstream signals to localized Rac activation and specific downstream pathways, and suggest that manipulating Tiam1-scaffold interactions can modulate Rac-dependent cellular behaviors.

NAD+ auxotrophy is bacteriocidal for the tubercle bacilli

The human tubercle bacillus Mycobacterium tuberculosis can synthesize NAD(+) using the de novo biosynthesis pathway or the salvage pathway. The salvage pathway of the bovine tubercle bacillus Mycobacterium bovis was reported defective due to a mutation in the nicotinamidase PncA. This defect prevents nicotinic acid secretion, which is the basis for the niacin test that clinically distinguishes M. bovis from M. tuberculosis. Surprisingly, we found that the NAD(+)de novo biosynthesis pathway (nadABC) can be deleted from M. bovis, demonstrating a functioning salvage pathway. M. bovisDeltanadABC fails to grow in mice, whereas M. tuberculosisDeltanadABC grows normally in mice, suggesting that M. tuberculosis can acquire nicotinamide from its host. The introduction of M. tuberculosis pncA into M. bovisDeltanadABC is sufficient to fully restore growth in a mouse, proving that the functional salvage pathway enables nicotinamide acquisition by the tubercle bacilli. This study demonstrates that NAD(+) starvation is a cidal event in the tubercle bacilli and confirms that enzymes common to the de novo and salvage pathways may be good drug targets.

Allelic imbalance at 13q31 is associated with reduced GPC6 in Chinese with sporadic retinoblastoma

BACKGROUND/AIMS

Loss of heterozygosity (LOH) has been discovered in retinoblastoma (RB) in previous studies. In this study, we aimed to discover potential tumour suppressor genes through investigation of the incidence of allelic loss in chromosome 1, 6, 9, 13, 19, 20, 21, 22 and X in Chinese sporadic retinoblastoma patients and to study the expression of genes flanking LOH region 13q31.

METHODS

Twenty-five microdissected RB samples were analysed to investigate the LOH in 140 microsatellite markers. Expression of genes flanking D13S265 was investigated by real-time quantitative-PCR on available frozen samples. The promoter and entire coding region of GPC6 were examined for sequence changes in an extended batch of 29 RB samples.

RESULTS

Allele losses were found in 92% (23/25) of the tumours. We identified a new LOH locus at 13q31 (D13S265) with a high occurrence rate (67%, 14/21) apart from the RB1 locus (68%, 17/25). Expression study detected the reduced expression of Glypican 6 (GPC6) transcript significantly associated with the LOH at 13q31 (p=0.024). Furthermore, mutation screening revealed no remarkable sequence alteration in GPC6 that could affect its expression.

CONCLUSION

Results suggest that a reduction in GPC6 mRNA in retinoblastoma is associated with the non-random allelic loss at 13q31 that could contribute to RB development.

Is ultrasonography-guided modified coaxial core biopsy of the breast a better technique?

OBJECTIVE

To compare the diagnostic rate, patient comfort, and complications of ultrasonography-guided breast biopsy using a modified coaxial technique with ultrasonography-guided fine needle aspiration and traditional core biopsy. A secondary objective was to describe the use of the coaxial technique for the biopsy of breast lesions and our initial experience.

DESIGN

Retrospective study.

SETTING

A regional hospital in Hong Kong.

PATIENTS

Patients, who were referred for ultrasonography-guided fine needle aspiration or biopsy from 23 November 2007 to 19 March 2008, were divided into three groups. For breast lesions of 8 mm or smaller, fine needle aspirations were performed. For breast lesions larger than 8 mm, the patients were randomly divided into groups receiving traditional core biopsies and coaxial biopsies. The pathological reports were reviewed.

MAIN OUTCOME MEASURES

Diagnostic rate, patient comfort assessed in terms of pain, and any procedural complications.

RESULTS

A total of 45 ultrasonography-guided fine needle aspirations or biopsies of breast lesions were performed. All core biopsies using the traditional core technique (n=15) and coaxial technique (n=16) were diagnostic. While for fine needle aspirations, three (21%) of 14 were not diagnostic and repeat biopsies were undertaken for the corresponding patients. Except for one breast lesion biopsied with the coaxial technique that revealed invasive ductal carcinoma, all others yielded benign lesions. The average pain score for coaxial biopsies was 2.2, while for traditional core biopsies and fine needle aspirations, average scores were 3.7 and 3.8, respectively (P=0.022). No procedure-related complication was documented with either of the three techniques.

CONCLUSION

Modified coaxial core biopsy of the breast has an optimal diagnostic rate and hence avoids the need for repeat biopsies. It is associated with better patient comfort and no increase in the risk of complications.

Simple co-electrodeposition of functionalized multi-walled carbon nanotubes/chitosan composite coating on mainspring for enhanced modulus of elasticity

Co-electrodeposition of functionalized multi-walled carbon nanotubes (f-MWCNTs) with chitosan was performed on pieces of a stainless steel mainspring. Under moderate conditions, composite coatings with controllable thickness from a few hundred nanometers to tens of micrometers can be achieved. After coating an 8 microm composite layer on a piece of mainspring 120 microm thick (i.e. 6.7% increase in thickness), the Young's modulus of the mainspring was found to have increased by more than approximately 25%. Moreover, the coated mainsprings possess much stronger mechanical strength as demonstrated by fatigue tests. The significant enhancement of Young's modulus and intrinsic strength are mostly attributed to the effect exerted by the subtle combination of chitosan and MWCNT. In the current study, the intensive cross-linkages formed between the -COOH groups in f-MWCNTs and the hydroxyl (-OH) and amino (-NH2) groups in chitosan were exploited. The chitosan molecular chains and f-MWCNTs both chemically react and physically knot with each other, leading to a three-dimensional interlaced f-MWCNT/chitosan composite coating. The reported co-electrodeposition provides a simple approach to form a stable, reproducible and rigid f-MWCNTs composite coating, which leads to the realization of a high-performance mainspring with reinforced mechanical strength.