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.

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.

The limited value of triage vital signs in predicting influenza infection in children aged 5 years and under in the emergency department: A single-center retrospective cross-sectional study

Diagnosing influenza in children aged 5 years and under can be challenging because of their difficulty in verbalizing symptoms. This study aimed to explore the value of the triage heart rate (HR), respiratory rate (RR), and temperature, either alone or when combined with individual symptoms and signs, in predicting influenza infection in this age group.This was a retrospective study covering 4 influenza seasons from 2017 to 2019 in an emergency department (ED) in Hong Kong. We recruited patients ≤5 years of age who had an reverse transcription polymerase chain reaction influenza test within 48 hours of ED presentation. The diagnostic performance of the triage HR, RR, and temperature was evaluated as dichotomized or categorized values with diagnostic odds ratios (DORs) calculated based on different age-appropriate thresholds. Linear discriminant analysis was performed to assess the combined discriminatory effect of age, HR, RR, and temperature as continuous variables.Of 322 patients (median age 26 months), 99 had influenza A and 13 had influenza B infection. For HR and RR dichotomized based on age-appropriate thresholds, the DORs ranged from 1.16 to 1.54 and 0.78 to 1.53, respectively. A triage temperature ≥39.0 °C had the highest DOR (3.32) among different degrees of elevation of temperature. The diagnostic criteria that were based on the presence of fever and cough and/or rhinitis symptoms had a higher DOR compared with the Centers for Disease Control and Prevention influenza-like illness criteria (4.42 vs 2.41). However, combining HR, RR, or temperature with such diagnostic criteria added very little to the diagnostic performance. The linear discriminant analysis model had a high specificity of 92.5%, but the sensitivity (18.3%) was too low for clinical use.Triage HR, RR, and temperature had limited value in the diagnosis of influenza in children ≤5 years of age in the ED. Fever and cough and/or rhinitis symptoms had a better diagnostic performance than the Centers for Disease Control and Prevention influenza-like illness criteria in predicting influenza in this age group.

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

Comparison of the Efficiency and Usability of Aerosol Box and Intubation Tent on Intubation of a Manikin Using Personal Protective Equipment: A Randomized Crossover Study

Background

The aerosol box and intubation tent are improvised barrier-enclosure devices developed during the novel coronavirus pandemic to protect health care workers from aerosol transmission.

Objective

Using time to intubation as a crude proxy, we aimed to compare the efficiency and usability of the aerosol box and intubation tent in a simulated manikin.

Methods

This was a single-center, randomized, crossover manikin study involving 28 participants (9 anesthetists, 16 emergency physicians, and 3 intensivists). Each participant performed rapid sequence intubations in a random sequence of three different scenarios: 1) no device use; 2) aerosol box; 3) intubation tent. We compared the time to intubation between different scenarios.

Results

The median total intubation time with no device use, aerosol box, and intubation tent were 23.7 s (interquartile range [IQR] 19.4–28.4 s), 30.9 s (IQR 24.1–52.5 s), and 26.0 s (IQR 22.1–30.8 s), respectively. Post hoc analysis showed a significantly longer intubation time using the aerosol box compared with no device use (p < 0.001) and compared with the intubation tent (p < 0.001). The difference between the intubation tent and no device use was not significant. The first-pass intubation success rate did not differ between the groups. Only aerosol box use had resulted in breaches of personal protective equipment. Participants considered intubation with the intubation tent more favorable than the aerosol box.

Conclusions

The intubation tent seems to have a better barrier-enclosure design than the aerosol box, with a reasonable balance between efficiency and usability. Further evaluation of its efficacy in preventing aerosol dispersal and in human studies are warranted prior to recommendation of widespread adoption.

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

Clinical, laboratory, and radiological features indicative of novel coronavirus disease (COVID-19) in emergency departments - a multicentre case-control study in Hong Kong

Objectives

Little is known about the value of routine clinical assessment in identifying patients with coronavirus disease 2019 (COVID‐19) in the emergency department (ED). We aimed to compare the exposure history, signs and symptoms, laboratory, and radiographic features of ED patients who tested positive and negative for COVID‐19.

Methods

This was a case‐control study in 7 EDs in Hong Kong from 20 January to 29 February 2020. Thirty‐seven patients with laboratory‐confirmed COVID‐19 were age‐ and sex‐matched to 111 controls. We compared the groups with univariate analysis and calculated the odds ratio (OR) of having COVID‐19 for each characteristic that was significantly different between the groups with adjustment for age and presumed location of acquiring the infection.

Results

There were no significant differences in patient characteristics and reported symptoms between the groups. A positive contact history within 14 days (adjusted OR 37.61, 95% CI: 10.86–130.19), bilateral chest radiograph shadow (adjusted OR 13.19, 95% CI: 4.66–37.35), having prior medical consultation (adjusted OR 7.43, 95% 2.89–19.09), a lower white blood cell count (adjusted OR 1.30, 95% CI: 1.11–1.51), and a lower platelet count (adjusted OR 1.07, 95% CI: 1.01–1.12) were associated with a higher odds of COVID‐19 separately. A higher neutrophil count was associated with a lower odds of COVID‐19 (adjusted OR 0.77, 95% CI: 0.65–0.91).

Conclusion

This study highlights a number of clinical features that may be useful in identifying high‐risk patients for early testing and isolation while waiting for the test result. Further studies are warranted to verify the findings.

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

Injury patterns of mass casualty incidents involving high-speed passenger ferries presenting to accident and emergency departments in Hong Kong: a retrospective review

BACKGROUND

Accidents involving high-speed passenger ferries have the potential to cause mass-casualty incidents (MCIs), yet there is a lack of relevant studies available to inform hospital disaster preparedness planning.

OBJECTIVE

The objective was to study the injury patterns and outcomes of MCI victims involved in high-speed passenger ferry accidents in Hong Kong waters.

METHODS

A retrospective study was conducted from 1 January 2005 to 31 December 2015. All MCIs involving high-speed passenger ferries were captured from the Marine Department of Hong Kong. Victims of all age who were sent to the accident and emergency departments (A&Es) of seven public hospitals around Victoria Harbour, including three trauma centres, were identified from electronic disaster registries of the study hospitals. Data on injury patterns and outcomes were extracted from medical records with the Injury Severity Score (ISS) calculated for each victim. The Kruskal-Wallis test was used to compare medians of the ISS across different mechanisms of injury. Multivariable logistic regression was performed to identify independent predictors for major trauma (ISS≥16).

RESULTS

During the study period, eight MCIs involving high-speed passenger ferries were reported and 512 victims (median age: 44 years, age range: 2-85 years) were sent to the study hospitals. The A&E triage categories were Cat 1, 3.1%; Cat 2, 4.3%; Cat 3, 19.3%; Cat 4, 72.9%; and Cat 5, 0.4%, respectively. The median ISS was 1.0 (interquartile range: 1.0-2.0). Fourteen victims (2.7%) had an ISS≥16 and age was the only independent predictor for major trauma (OR 1.06, p = 0.025, 95% CI 1.01-1.11). Trauma call was activated at A&E for 11 victims. In total, 100 victims (19.5%) were admitted to the study hospitals, including 19 (3.5%) and 15 (2.9%) who required surgery and intensive care unit stay, respectively. Eleven victims (2.1%) died, mostly due to drowning.

CONCLUSION

MCIs involving high-speed passenger ferries can result in a sudden surge in demand for both A&E and in-patient care, though the majority of victims may have minor injuries. Better access to lifejackets and mandatory seatbelt use may help to reduce injuries and deaths.

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.

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.

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.

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.

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.

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.

Cross-linking organic semiconducting molecules by preferential C-H cleavage via “chemistry with a tiny hammer”

In the context of collision-induced dissociation in chemistry and kinematics in physics, we have determined that a beam of hyperthermal protons can be used as tiny hammers to preferentially break the C-H bonds of hydrocarbon precursor molecules adsorbed on a conductive substrate with little damage to other chemical bonds. The activated molecules are thereby converted to a cross-linked molecular network, with its chemical properties tailored by the preservation of the chemical functional groups of the precursors and with its physical properties tuned by the degree of cross-linking. This “chemistry with a tiny hammer” process is adopted to induce inter-chain cross-linking of the semiconducting molecular chains in poly (3,4-ethylenedioxythiophene) molecular films and to raise the electrical conductivity and stability of the molecular films. The results exemplify the unusual reaction design of this process as well as its application in electronic and optoelectronic device fabrication. The application is particularly attractive because the process does not require any chemical additives or catalysts other than a beam of protons, and it needs no thermal budget.Key words: organic semiconductor, polymeric semiconductor, cross-linking, polymer, collision, dissociative collision, molecular electronics, device fabrication.

Update on clarithromycin resistance in Helicobacter pylori in Hong Kong and its effect on clarithromycin-based triple therapy

AIM

To determine the antibiotic susceptibility of Helicobacter pylori and evaluate the efficacy of a clarithromycin-based triple therapy in relation to antibiotic resistance.

METHODS

Consecutive patients referred for upper endoscopy due to dyspeptic symptoms were recruited. Gastric biopsies were obtained for the CLO test, histology and culture. Antibiotic susceptibility was assessed by the E-test. Patients with H. pylori infection received rabeprazole 20 mg, clarithromycin 500 mg, and amoxicillin 1,000 mg, all twice daily for 7 days.

RESULTS

Of 234 patients recruited, 124 were H. pylori-positive and culture was successful in 102 patients. The updated prevalences of resistance to clarithromycin, amoxicillin and metronidazole were 7.8, 0 and 39.2%, respectively. A total of 86 patients received 1-week triple therapy with rabeprazole 20 mg, clarithromycin 500 mg, and amoxicillin 1,000 mg, all twice daily, and 81 patients attended the follow-up test. Eradication rates by per-protocol and intention-to-treat analysis were 92.6 and 87.2%, respectively. The eradication rate by per protocol was significantly higher in patients with clarithromycin-susceptible strains than in those with clarithromycin-resistant strains (98.6 vs. 28.6%, p < 0.001).

CONCLUSION

Clarithromycin resistance reduces the clinical efficacy of clarithromycin-based triple therapy. However, due to the low prevalence of clarithromycin resistance, clarithromycin-based therapy is still the first choice for clinical use.

Trends in the prevalence of peptic ulcer disease and Helicobacter pylori infection in family physician-referred uninvestigated dyspeptic patients in Hong Kong

BACKGROUND

Peptic ulcer disease is mainly caused by Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs.

AIM

To investigate the trends in the prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use in uninvestigated dyspeptic patients over recent years in Hong Kong.

METHODS

Data from consecutive patients with uninvestigated dyspeptic symptoms referred by family physicians for open access upper endoscopy during 1997 and 2003 were analysed in relation to peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use.

RESULTS

Among 2700 patients included, 405 (15%) had peptic ulcer disease and 14 (0.5%) had gastric cancer. There was a reduced trend from 1997 to 2003 in the prevalence of peptic ulcer disease (17, 20, 14, 16, 13, 14 and 14%, respectively, chi2 = 5.80, P = 0.016) (mainly because of decrease in duodenal ulcers), H. pylori infection (44, 50, 49, 44, 40, 40, 36 and 43%, respectively, chi2 = 13.55, P < 0.001) and non-steroidal anti-inflammatory drug use (13, 5, 5, 6, 3, 4, 4 and 5% respectively, chi2 = 13.61, P < 0.001). The prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use between 2001 and 2003 were significantly lower than that between 1997 and 2000 (17% vs. 13%, OR = 0.78, 95% CI: 0.63-0.96, P = 0.020 for peptic ulcer disease; 47% vs. 39%, OR =0.72, 95% CI: 0.60-0.86, P < 0.001 for H. pylori infection; and 6% vs. 4%, OR = 0.56, 95% CI: 0.39-0.82, P = 0.002 for non-steroidal anti-inflammatory drug use). H. pylori infection was associated with both duodenal ulcer (OR = 15.87, 95% CI: 10.60-23.76, P < 0.001) and gastric ulcer (OR = 3.12, 95% CI: 2.15-4.53, P < 0.001) whereas non-steroidal anti-inflammatory drug use was only associated with gastric ulcer (OR = 2.97, 95% CI: 1.70-5.20, P < 0.001).

CONCLUSIONS

The prevalence of peptic ulcer disease, mainly duodenal ulcers, was reduced in association with a decreasing trend in the prevalence of H. pylori infection and non-steroidal anti-inflammatory drug use from 1997 to 2003.

A pilot study of participation in faecal occult blood testing and screening colonoscopy after health education in Hong Kong

Colorectal cancer is the second commonest cancer in Hong Kong. The screening behaviour of the Chinese population has not been assessed. The aim of this study is to report a pilot study of educating and subsequent evaluation of colorectal cancer screening behaviour in the Hong Kong Chinese population. Subjects were invited to attend a free health talk on colorectal cancer. Both self-paid faecal occult blood testing (FOBT) and free screening colonoscopy were offered after the education programme. Of the participants taking part in the education programme 113/119 (95%) completed the FOBT. Of the FOBT 8/113 (7%) showed positive result and three patients had neoplasia at colonoscopy. Twenty-five patients with negative FOBT also completed colonoscopy; two had adenomas. Screening colonoscopy after FOBT was accepted by 28% of subjects. Those younger than 65 years and those with a positive FOBT (7/8 versus 25/105 for those with negative FOBT, P=0.0003) were more likely to agree to screening colonoscopy. In conclusion, health education is important for ensuring high acceptance and implementation of colorectal cancer screening in Hong Kong Chinese. FOBT is an acceptable and feasible screening method in Hong Kong.

Biodegradation of phenanthrene by the indigenous microbial biomass in a zinc amended soil

AIMS

To study the effect of zinc on the biodegradation of phenanthrene by the microbial biomass in soil.

METHODS AND RESULTS

Uncontaminated soil was amended with zinc and phenanthrene as single or co-contaminants, and microbial metabolic activity was measured using an intracellular dehydrogenase enzyme bioassay over 37 days. Contaminants were amended at optimum, action and double the action level specified in 'The New Dutch List' (Ministry of Housing, Spatial Planning and Environment, the Netherlands, 2000). Microbial activity in soils with zinc or phenanthrene alone indicated the presence of tolerant, albeit inhibited soil micro-organisms. A zinc concentration at the optimum level of 140 mg kg(-1) in the co-contaminated soil (phenanthrene at 40 mg kg(-1)) resulted in marginal stimulation of the rate of phenanthrene biodegradation. However, Zn2+ concentrations at the action and double the action level of zinc (720 and 1440 mg kg(-1)) inhibited phenanthrene degradation.

CONCLUSIONS

Biodegradation of phenanthrene in soils co-contaminated with zinc at concentrations above the action value is impeded.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bioremediation efforts to remove polycyclic aromatic hydrocarbon in zinc co-contaminated soils are likely to be constrained.

A secure communication scheme based on the phase synchronization of chaotic systems

Phase synchronization of chaotic systems with both weak and strong couplings has recently been investigated extensively. Similar to complete synchronization, this type of synchronization can also be applied in secure communications. We develop a digital secure communication scheme that utilizes the instantaneous phase as the signal transmitted from the drive to the response subsystems. Simulation results show that the scheme is difficult to be broken by some traditional attacks. Moreover, it operates with a weak positive conditional Lyapunov exponent in the response subsystem.

A prospective comparison of performance of biopsy forceps used in single passage with multiple bites during upper endoscopy

BACKGROUND AND STUDY AIMS

A single biopsy is usually obtained for each passage of a biopsy forceps. It was hypothesized that multiple bites per passage might improve the quantity and quality of tissue obtained, without significant artifacts. This hypothesis was tested in a prospective, pathologist-blinded study using different forceps.

PATIENTS AND METHODS

Forty consecutive patients who underwent elective upper endoscopy were included. Five different forceps were used in six different ways, varying in the number of bites taken per passage. Two pathologists, who were blinded to the type of biopsy forceps used, evaluated the specimens according to the parameters of maximum weight (mg), size of largest fragment (mm), depth, squash artifact, adequacy, and overall rating.

RESULTS

A total of 240 biopsy specimens were obtained. The Microvasive Multibite and Megabite forceps obtained specimens with the maximum weight (P<0.05) and the largest size (P<0.05), respectively. Alligator forceps were able to obtain specimens significantly larger in size than the oval-shaped forceps (P<0.05). The Olympus FB-24K forceps performed best in both the adequacy score and the overall rating score (P<0.05).

CONCLUSIONS

Forceps with a needle, or the Multibite forceps, allow more biopsies to be taken per passage and improve the quality of tissues obtained. "Needleless" forceps can be used to obtain two samples per passage through the endoscope that are as good as when only one sample is collected. This approach can save time, and causes no significant damage to the biopsy specimens.

A rapid-release 50-mg tablet-based 13C-urea breath test for the diagnosis of Helicobacter pylori infection

BACKGROUND

Recently, a rapid-release 100-mg 13C-urea tablet with citrate supplement (Diabact UBT) showed excellent performance in a European population.

AIM

To investigate the accuracy of a 50-mg tablet-based 13C-urea breath test protocol.

METHODS

: Consecutive dyspeptic patients referred for upper endoscopy were recruited. 13C-Urea breath test was performed using a 50-mg 13C-urea tablet (Diabact UBT) and compared with the gold standard (rapid urease test and histology). Baseline, 10-min, 20-min and 30-min breath samples were collected in all cases. The cut-off values at each measurement interval were determined by three standard deviations above the mean excess delta 13CO2 excretion of Helicobacter pylori-negative patients.

RESULTS

Two hundred patients (150 before therapy and 50 after therapy) were available for analysis, with a mean age of 48.4 years, and 99 patients (50%) were H. pylori positive. The sensitivity and specificity of the 50-mg tablet-based 13C-urea breath test at 10 min, 20 min and 30 min were 100% and 98%, 100% and 100%, and 100% and 98%, respectively.

CONCLUSION

A 20-min, 50-mg tablet-based 13C-urea breath test (Diabact UBT) protocol is highly accurate for the diagnosis of H. pylori infection.

MRI of muscular hamartoma of the breast

Muscular hamartoma is a well-demarcated tumour composed of smooth muscle and adipose tissue. We report the MRI findings of a patient with benign breast neoplasm. To the best of our knowledge, its appearance has not been previously reported.

Phase synchronization in coupled chaotic oscillators with time delay

The phase synchronization (PS) of two Rössler oscillators with time-delayed signal coupling is studied. We find that time delay can always lead to PS even when the delay is very long. Moreover, with the increase of time delay, the coupling strength at the transition to PS undergoes a nearly periodic wave distribution. At some fixed time-delayed signal coupling, a PS region is followed by a non-PS region when the coupling strength increases. However, an increase of the coupling leads to the PS state again. This phenomenon occurs in systems with a relatively large PS transition point.

Clinical and endoscopic characteristics of non-Helicobacter pylori, non-NSAID duodenal ulcers: a long-term prospective study

BACKGROUND

The proportion of duodenal ulcers not associated with Helicobacter pylori infection or the use of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing.

AIM

To identify the clinical and endoscopic characteristics of non-H. pylori, non-NSAID duodenal ulcers.

METHODS

Clinical and endoscopic data and H. pylori status were prospectively collected from consecutive patients who underwent upper endoscopy from 1997 to 1999. Patients with duodenal ulcers were identified, and those with non-H. pylori, non-NSAID duodenal ulcers were analysed further.

RESULTS

A total of 11 717 upper endoscopies were performed in 8344 patients. Of these, 1153 (14%) had duodenal ulcers. Of 599 patients with active ulcers and known H. pylori status, 104 (17%) had ulcers not associated with H. pylori or the use of NSAIDs, 393 (66%) had ulcers associated with H. pylori alone, 51 (8.5%) had ulcers associated with the use of NSAIDs alone and 51 (8.5%) had ulcers associated with both. Multivariate logistic regression analysis revealed that the presence of concomitant diseases (odds ratio=15.0; 95% confidence interval, 8.64-25.9; P < 0.001) and the absence of epigastric pain/discomfort (odds ratio=0.52; 95% confidence interval, 0.29-0.91; P=0.022) were independent predictors for non-H. pylori, non-NSAID duodenal ulcers.

CONCLUSIONS

Non-H. pylori, non-NSAID duodenal ulcers exhibit certain distinct clinical and endoscopic characteristics. The presence of concomitant diseases is an important predictive factor.

Efficient uptake of Yersinia pseudotuberculosis via integrin receptors involves a Rac1-Arp 2/3 pathway that bypasses N-WASP function

Efficient uptake of Yersinia pseudotuberculosis into cultured mammalian cells is the result of high-affinity binding of invasin to beta1 chain integrins. We demonstrate here that uptake requires Rac1 and Arp 2/3 function. Bacterial uptake was stimulated by GTPgammaS, but was inhibited in mammalian cells transfected with the interfering Rac1-N17 derivative. Rac1 was found to be activated in response to integrin engagement by invasin, whereas Rac1 and Arp 2/3 were found to be intensely localized around phagosomes bearing bacteria, indicating a specific role for Rac1 signalling from the nascent phagosome to downstream effectors. To determine whether the Arp 2/3 complex was a component of this proposed pathway, cells overproducing various derivatives of Scar1/WAVE1, an Arp 2/3-binding protein, were analysed. Sequestration of Arp 2/3 away from the phagocytic cup as a result of Scar1/WAVE1 overproduction dramatically inhibited uptake. To determine whether signalling from Rac1 to Arp 2/3 occurred via N-WASP, uptake was analysed in a cell line lacking expression of WASP and N-WASP. Uptake was unaffected by the absence of these proteins, indicating that beta1 integrin signalling from Rac1 to Arp 2/3 can occur in the absence of N-WASP function.

Prevalence of and risk factors for erectile dysfunction in Hong Kong diabetic patients

AIM

To estimate the prevalence of erectile dysfunction (ED) in Chinese diabetic men and to identify its risk factors, we carried out a cross-sectional survey of 500 Chinese diabetic men attending a community hospital diabetic clinic in Hong Kong.

METHODS

Patients were interviewed and asked to report on their experience of ED as defined in the National Institutes of Health Consensus Conference 1993. Diabetic complications and patient clinical data were obtained from patients' medical records.

RESULTS

Of the 486 patients studied, the prevalence of ED was 63.6% (95% confidence interval 59.3-67.9%). The prevalence of ED increased with age, from 33.3% to 73.8% for diabetic men aged between 21 and 80 years (P = 0.001). Severity of ED also increased with age. Among diabetic men with ED, there was no report of complete ED for diabetic men aged 40 years and below, whereas the proportion of patients with complete ED increased from 7.4% to 71.1% between the ages of 41 and 80 years. ED occurred early in the course of the disease, with a prevalence increasing from 56.0% in men with diabetes mellitus (DM) for < 5 years to 72.0% in those with DM for > 20 years (P = 0.038). Duration of DM was also associated with severity; the proportion of patients with complete ED increased from 30.8% for those with DM for < 5 years to 72.2% for those with DM for > or = 20 years (P < 0.001). Using logistic regression analysis, DM duration, diabetic complications including retinopathy, abnormal albuminuria and sensory neuropathy, and higher level of education were associated with a higher risk of ED. By polychotomous logistic regression, age was the only factor found to be associated with the severity of ED, after adjusting for other variables.

CONCLUSIONS

Chinese diabetic patients have a prevalence of self-reported ED that appears to be higher than that of Western populations. This may be due to cultural differences and the association of abnormal albuminuria and hypertension.

Twenty-minute 50 mg 13C-urea breath test without test meal for the diagnosis of Helicobacter pylori infection in Chinese

BACKGROUND

We have previously shown that the 75 mg 13C-urea breath test without citrate test meal is highly accurate for the diagnosis of Helicobacter pylori infection in Chinese subjects. A lower dose 50 mg 13C-urea breath test protocol with a sampling time at 20 min has not been validated previously.

AIM

To investigate the accuracy of a 20-min 50 mg 13C-urea breath test protocol in Chinese subjects.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. 13C-urea breath test was performed using (a) 75 mg and 50 mg of 13C-urea on two separate days without a test meal, and (b) 50 mg of 13C-urea with 2.4 g citrate as test meal, and compared with the gold standard [rapid urease test (CLO test) and histology]. Baseline, 20-min and 30-min breath samples were collected in all cases.

RESULTS

Two hundred and six patients were tested. The accuracy of the 50 mg 13C-urea breath test (no citrate) at 20 min and 30 min was 98%, comparable to that of the 50 mg 13C-urea breath test with citrate (99.1%) and the 75 mg 13C-urea breath test without citrate (100%).

CONCLUSIONS

A 20-min 50 mg 13C-urea breath test without citrate produced highly accurate results for the diagnosis of Helicobacter pylori infection and is more economical and convenient for the Chinese population.

Intermittent phase synchronization of coupled spatiotemporal chaotic systems

Phase synchronization is studied with a discrete system formed by two coupled map lattices, in which phases are measured in two-dimensional vectors. Simulation results show that by imposing external coupling between the two lattices, phase synchronization can be found in all two-dimensional phase planes between them. When the system is approaching the phase synchronizing state, unstable phase synchronization is observed. This is referred to as intermittent phase synchronization that appears when the trajectories on two interacting phase planes have opposite directions of rotation but with only a small phase difference. The intermittent phase synchronization could also be observed in coupled autonomous systems with diffusive attractors although their phase concepts are inconsistent. Our results show that the intermittent phase synchronization of both discrete and autonomous systems relates to the diffusion or the complexity of the attractors.

Bacillus subtilis CodY represses early-stationary-phase genes by sensing GTP levels

CodY, a highly conserved protein in the low G + C, gram-positive bacteria, regulates the expression of many Bacillus subtilis genes that are induced as cells make the transition from rapid exponential growth to stationary phase and sporulation. This transition has been associated with a transient drop in the intracellular pool of GTP. Many stationary-phase genes are also induced during exponential-growth phase by treatment of cells with decoyinine, a GMP synthetase inhibitor. The effect of decoyinine on an early-stationary-phase gene is shown here to be mediated through CodY and to reflect a reduction in guanine nucleotide accumulation. CodY proved to bind GTP in vitro. Moreover, CodY-mediated repression of target promoters was dependent on a high concentration of GTP, comparable to that found in rapidly growing exponential-phase cells. Because a codY-null mutant was able to sporulate under conditions of nutrient excess, CodY also appears to be a critical factor that normally prevents sporulation under such conditions. Thus, B. subtilis CodY is a novel GTP-binding protein that senses the intracellular GTP concentration as an indicator of nutritional conditions and regulates the transcription of early-stationary-phase and sporulation genes, allowing the cell to adapt to nutrient limitation.

High prevalence of mixed infections by Helicobacter pylori in Hong Kong: metronidazole sensitivity and overall genotype

BACKGROUND

Diversity in metronidazole susceptibility and genotypes of Helicobacter pylori have been reported with varying results in different areas.

AIMS

To investigate the prevalence of multiple strain infection in a symptomatic Chinese population and to determine the metronidazole susceptibility pattern and genotypic characteristics of these infecting strains.

METHODS

Gastric biopsies from antrum, body and cardia were taken during upper endoscopy in symptomatic patients referred to our department. Pooled cultures and single colony isolates were obtained and tested for metronidazole susceptibility and random amplified polymorphic DNA (RAPD) fingerprint patterns.

RESULTS

A total of 461 isolates were successfully cultured from 46 patients. Fifty-seven per cent of subjects had metronidazole-resistant strains. Among them, 77% carried a mixture of sensitive and resistant strains, non-uniformly distributed in the gastric mucosa. Mixed genotypes were found by RAPD typing in 24% of subjects. These did not correlate with the metronidazole susceptibility/resistance pattern.

CONCLUSION

H. pylori infections with mixed metronidazole sensitive/resistant strains and mixed genotypes are common in Hong Kong. This makes it prudent to use bacterial strains from several biopsy sites when testing for traits such as drug resistance or virulence in relation to disease.

Phase signal coupling induced n:m phase synchronization in drive-response oscillators

We have studied phase synchronization between two identical Rössler oscillators connected in the drive-response configuration by a single phase signal. Before the transition to phase synchronization, the distribution of the time interval between consecutive 2pi jumps shows several sharp peaks. With a strong phase signal coupling, the n:m phase synchronization between the oscillators can be achieved. For the n (not equal) m phase synchronizing state, some values of coupling strength result in a phenomenon characterized by a reduction in the mean amplitude of the response termed amplitude reduction. In these regions, the mean rotation speed of the response remains approximately constant while the locking ratio n:m varies.