Harnessing the potential of data-driven strategies to optimise transfusion practice

No one doubts the significant variation in the practice of transfusion medicine. Common examples are the variability in transfusion thresholds and the use of tranexamic acid for surgery with likely high blood loss despite evidence-based standards. There is a long history of applying different strategies to address this variation, including education, clinical guidelines, audit and feedback, but the effectiveness and cost-effectiveness of these initiatives remains unclear. Advances in computerised decision support systems and the application of novel electronic capabilities offer alternative approaches to improving transfusion practice. In England, the National Institute for Health and Care Research funded a Blood and Transplant Research Unit (BTRU) programme focussing on 'A data-enabled programme of research to improve transfusion practices'. The overarching aim of the BTRU is to accelerate the development of data-driven methods to optimise the use of blood and transfusion alternatives, and to integrate them within routine practice to improve patient outcomes. One particular area of focus is implementation science to address variation in practice.

Impacts of climate change on drinking water quality in Norway

Climate change will lead to higher temperatures, increased precipitation and runoff, as well as more intense and frequent extreme weather events in Norway. More extreme rainfall and increased runoff are historically associated with higher concentrations of indicator bacteria, colour and turbidity in raw water of Norwegian waterworks. Regional information about the risk for drinking water deterioration by the end of the century is essential for evaluating potential treatment capacity upgrades at the waterworks. We combined locally downscaled future climate scenarios with historical associations between weather/runoff and water quality from a wide spread of waterworks in Norway. With continued climate change, we estimate higher concentrations of water quality indicators of raw water by the end of the century. The water quality is estimated to deteriorate mainly due to the projected increase in rainfall, and mainly in the Western and Northern parts of Norway. While large waterworks seem to be able to adapt to future conditions, the degradation of raw water quality may cause future challenges for the treatment processes at smaller waterworks. Combining these results with further studies of treatment effects and microbial risk assessments is needed to ensure sufficient treatment capacities of the raw water in the future.

Associations between salivary cytokines and periodontal and microbiological parameters in orthodontic patients

Orthodontic treatment can lead to microbial-induced gingival inflammation and aseptic periodontal inflammations. The aim of this study was to investigate the relationship between salivary pro-inflammatory cytokines levels with gingival health status and oral microbe loads among patients undergoing orthodontic treatment.The present investigation was a cross-sectional study among a sample of 111 consecutive orthodontic patients (mean age 18.4 ± 4.4 years). Clinical examinations were conducted to assess the gingival health status employing the Modified Gingival Index, Gingival Bleeding Index, and Plaque Index. Salivary microbiological assessments of total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count were undertaken. Saliva immunological assessments included Interleukin-1Beta (IL-1β) and macrophage migration inhibitory factor (MIF) ELISA assays.The mean ± standard deviation of salivary IL-1β was 83.52 ± 85.62 pg/ml and MIF was 4.12 ± 0.96 ng/ml. Moderate positive correlations were found between salivary IL-1β levels and total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count (r = 0.380-0.446, P < .001), and weak positive correlations between salivary MIF levels and total salivary aerobic and anaerobic bacteria counts (r = 0.249-0.306, P < .01) were observed. A positive correlation was found between salivary IL-1β levels and Bleeding Index (r = 0.216, P < .05).The level of salivary IL-1β positively correlates with oral bacterial load among orthodontic patients; the relationship between inflammatory cytokines and oral microflora deserved further study.

High seroprevalence of anti-Fasciola antibody among cattle farm workers and dwellers in Kelantan

Human fascioliasis is a public health problem particularly in areas where ruminants are raised. The aims of this study were to determine the seroprevalence of anti-Fasciola antibody and the associated risk factors among cattle farm workers and dwellers in Kelantan. A total of 90 blood samples were collected in this cross-sectional study. A set of validated questionnaire was used to obtain information on socio-demographic profiles and dietary habits of participants. The sera were subjected to enzyme linked immunosorbent assay (ELISA) for the detection of anti-Fasciola IgG antibody. The association between seropositivity and the significant risk factors were determined via logistic regression. From the result, serological screening revealed 60 (67%) participants positive for anti-Fasciola IgG antibody. The factors found to be significantly associated with seropositivity against anti-Fasciola IgG antibody were the age group of 18 years old and above with calculated odds ratio of 3.2 times (p=0.032) and the duration of farming activities of more than 5 years with calculated odds ratio of 2.6 times (p=0.036). In conclusion, Fasciola infection is prevalent among cattle farm workers and dwellers in Kelantan.

The metaphyseal sleeve: an unexplored option in the treatment of complex primary knee osteoarthritis

BACKGROUND

In an ever-aging society that as a whole has become more affluent, significant emphasis has been accorded to an improved quality of life. Knee osteoarthritis is ever-increasingly treated with total knee arthroplasty. The benefits and satisfaction experienced by those who have undergone total knee replacements (TKR) are well documented in the literature. The issue arises when osteoarthritis of the affected knee is more complex than simple osteoarthritis, i.e. the patient has complex primary osteoarthritis. This collective term encompasses conditions such as massive bone loss, ligamentous laxity, coronal defects and those with contractures. There are various classifications to describe massive bone loss but we utilized the Anderson Orthopaedic Research Institute (AORI) classification. Numerous treatment options are available and we report the use of metaphyseal sleeves as a highly successful treatment option.

METHODS

We retrospectively reviewed all the patients at our centre who underwent primary TKR using the metaphyseal sleeves. Patients were assessed on symptoms and functional status, and radiographs were also taken to assess for osseointegration. Only patients who completed 2 years of follow up were included in our study.

RESULTS

The updated (2011) Knee Society Score (KSS) was used in conjunction with radiological assessments at each follow up. Mean KSS scores improved from 53.83 preoperatively to 193.39 postoperatively. All patients demonstrated increasing osseointegration throughout follow up.

CONCLUSION

The metaphyseal sleeve is an excellent treatment option for complex primary osteoarthritic knees with good results objectively, functionally and radiologically and would be a great choice for all orthopaedic surgeons to include in their armamentarium.

Erysipelothrix Septicaemia and Hepatitis in a Colony of Humboldt Penguins (Spheniscus humboldti)

This report describes an outbreak of erysipelas in a colony of captive Humboldt penguins (Spheniscus humboldti). The only previously reported case in a related species was of an individual little blue penguin (Eudyptula minor). Five Humboldt penguins in a mixed colony displayed non-specific signs of illness, including lethargy, inappetence and regurgitation after movement for exhibit upgrading. There was no improvement after 5 days of treatment with oral enrofloxacin (10 mg/kg q24h). Four Humboldt penguins, including two that were not part of the original five displaying signs of illness, died during this outbreak and Erysipelothrix rhusiopathiae was cultured from organ samples collected post mortem. Oral clavulanic acid/amoxycillin (125 mg/kg q12h) was added to the treatment of the sick Humboldt penguins, as well as itraconazole (8.5 mg/kg q12h) and silymarin (10 mg/kg q24h) for 10 days (both per os), which resolved their clinical signs. The likely source of E. rhusiopathiae was the fish they were fed, but this could not be confirmed. Another contributing factor to the growth of E. rhusiopathiae in the exhibit pool was the increase in water temperature due to a fault in the water circulating system. The temperature of the pool water had increased to 29°C, which was rectified, and the water temperature decreased to 13°C. However, there was one further Humboldt penguin death after the decrease in water temperature. This episode suggests that E. rhusiopathiae infection should be high on the differential list of piscivorous avian species with non-specific clinical signs. A liver biopsy for bacterial culture and sensitivity may be required for definitive diagnosis.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Paraneoplastic relapsing minimal change disease associated with type A thymoma in an elderly patient: A case report and literature review

Thymoma is a rare mediastinal tumour that can be accompanied by different paraneoplastic syndromes. Here we report a case of Type A thymoma associated with relapsing minimal change disease (MCD). This case highlights: (1) The need to balance rapid prednisolone weaning against risk for relapse in an elderly patient at risk for steroid-induced complications. (2) The addition of calcineurin inhibitor in relapsed thymoma-related MCD, to achieve steroid sparing effects. Resection of the offending tumour and prompt immunosuppressive therapy are critical in getting best renal and overall outcomes in this rare entity.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Optimal designs for active controlled dose-finding trials with efficacy-toxicity outcomes

We derive optimal designs to estimate efficacy and toxicity in active controlled dose-finding trials when the bivariate continuous outcomes are described using nonlinear regression models. We determine upper bounds on the required number of different doses and provide conditions under which the boundary points of the design space are included in the optimal design. We provide an analytical description of minimally supported optimal designs and show that they do not depend on the correlation between the bivariate outcomes.

A Man with Head Injury

Head injury is common and can be associated with significant morbidity and mortality. We report a 71-year-old man with typical imaging findings of depressed skull fracture on plain film and computed tomography with images in multi-planar reformat and 3-dimensional volume rendering technique, followed by a brief review of the literature.

Prevalence and Distribution of Anti-Amoebic IgG Antibody among Orang Asli (Aborigines) in Peninsular Malaysia

Entamoeba species are commonly detected in stool samples of Orang Asli due to their substandard living conditions and poor hygiene. Among the Entamoeba spp., Entamoeba histolytica is the only known primary pathogenic species. This study determined the prevalence and distribution of anti-amoebic IgG antibody among Orang Asli in Peninsular Malaysia. The results would reflect the prevalence of amoebiasis in the population. This study analysed a total of 375 serum samples from archives of two Orang Asli projects conducted between 2011 and 2014. They were from six different states in Malaysia, namely Johor, Kedah, Kelantan, Pahang, Perak, and Selangor. Anti-amoebic IgG antibody was detected using an enzymelinked immunosorbent assay (ELISA) with crude soluble antigen produced from axenically grown E. histolytica trophozoites. From the analysis, the overall seropositivity was approximately 71% (266/375), while the seropositivity rates for each of the three Orang Asli tribes i.e. Senoi, Negrito and Proto-Malay, were 66% (137/208), 92% (103/112), and 43% (17/ 41) respectively. Orang Asli from Kedah [95% (52/55)] showed the highest seropositivity, followed by Kelantan [79% (54/68)], Perak [73% (78/107)], Pahang [60% (57/95)], Selangor [56% (14/25)], and Johor [48% (10/21)]. Orang Asli from rural [76% (192/254)] and peripheral urban [65% (69/106)] areas showed significantly higher seropositivity (p=0.002) than those from urban areas [36% (4/11)]. The high prevalences of anti-amoebic IgG antibody in these Orang Asli populations comprised both active and past infections. This study provides current insights of amoebiasis in selected Orang Asli settlements in Peninsular Malaysia. The high seropositivity of anti-amoebic IgG antibody suggests that the settlements are endemic for amoebiasis and there is a high risk of acquiring E. histolytica infection among the dwellers.

Endovascular Stent Graft Repair is an Effective and Safe Alternative Therapy for Arteriovenous Graft Pseudoaneurysms

OBJECTIVE/BACKGROUND

Pseudoaneurysm formation occurs in 2-10% of hemodialysis arteriovenous grafts (AVGs). Surgical repair often requires pseudoaneurysm resection, interposition graft placement, and insertion of a catheter as a bridge. Endovascular stent graft repair is a controversial alternative therapy. This study was performed to examine the effectiveness and mid-term outcomes of stent graft repair for AVG pseudoaneurysms.

METHODS

All patients who had undergone stent graft repair for AVG pseudoaneurysms between December 2012 and July 2015 were identified from hospital medical records for retrospective analysis. Outcome measures were technical success, early and late complications, and primary and secondary patency rates.

RESULTS

A total of 37 stent graft repairs of AVG pseudoaneurysms were performed in 35 patients (42.9% men; mean age 66.9 years). The mean time from AVG creation to pseudoaneurysm repair was 69 months. The indications of treatment (as per the institutional policy) were large pseudoaneurysm (56.7%), impending rupture (27.1%), and bleeding (16.2%). Mean pseudoaneurysm diameter was 23.0 mm. The most common diameter and length of stent graft used were 7 mm (67.6%) and 50 mm (48.6%), respectively. Technical success was 100%. Only one early complication occurred after stent graft repair, which was due to recurrence of the pseudoaneurysm as a result of a short landing zone. Late complications included infection (17.1%) and thrombosis (37.1%). The 1, 6, and 12 month primary patency rates were 89.2%, 55.5%, and 22.0%, respectively. The 1, 6, and 12 month secondary patency rates were 100%, 88.6%, and 78.6%, respectively. The median follow up was 12.3 months.

CONCLUSIONS

The study demonstrates that endovascular stent graft repair is an effective and safe alternative therapy for AVG pseudoaneurysms. However, the rate of thrombosis and infection was high and needs to be balanced against open surgery in future studies.

Primary ventriculoperitoneal shunting outcomes: a multicentre clinical audit for shunt infection and its risk factors

OBJECTIVES

To determine the frequency of primary ventriculoperitoneal shunt infection among patients treated at neurosurgical centres of the Hospital Authority and to identify underlying risk factors.

METHODS

This multicentre historical cohort study included consecutive patients who underwent primary ventriculoperitoneal shunting at a Hospital Authority neurosurgery centre from 1 January 2009 to 31 December 2011. The primary endpoint was shunt infection, defined as: (1) the presence of cerebrospinal fluid or shunt hardware culture that yielded the pathogenic micro-organism with associated compatible symptoms and signs of central nervous system infection or shunt malfunction; or (2) surgical incision site infection requiring shunt reinsertion (even in the absence of positive culture); or (3) intraperitoneal pseudocyst formation (even in the absence of positive culture). Secondary endpoints were shunt malfunction, defined as unsatisfactory cerebrospinal fluid drainage that required shunt reinsertion, and 30-day mortality.

RESULTS

A primary ventriculoperitoneal shunt was inserted in 538 patients during the study period. The mean age of patients was 48 years (range, 13-88 years) with a male-to-female ratio of 1:1. Aneurysmal subarachnoid haemorrhage was the most common aetiology (n=169, 31%) followed by intracranial tumour (n=164, 30%), central nervous system infection (n=42, 8%), and traumatic brain injury (n=27, 5%). The mean operating time was 75 (standard deviation, 29) minutes. Shunt reinsertion and infection rates were 16% (n=87) and 7% (n=36), respectively. The most common cause for shunt reinsertion was malfunction followed by shunt infection. Independent predictors for shunt infection were: traumatic brain injury (adjusted odds ratio=6.2; 95% confidence interval, 2.3-16.8), emergency shunting (2.3; 1.0-5.1), and prophylactic vancomycin as the sole antibiotic (3.4; 1.1-11.0). The 30-day all-cause mortality was 6% and none were directly procedure-related.

CONCLUSIONS

This is the first Hong Kong territory-wide review of infection in primary ventriculoperitoneal shunts. Although the ventriculoperitoneal shunt infection rate met international standards, there are areas of improvement such as vancomycin administration and the avoidance of scheduling the procedure as an emergency.

Non-tuberculous mycobacterial head and neck infections in children: Analysis of results and complications for various treatment modalities

OBJECTIVES

Analyze the results and complications of various surgical interventions in a large cohort of children with non-tuberculous mycobacterial (NTM) head and neck infections and suggest a heuristic treatment protocol for managing this condition while aiming to maximize cure and minimize complications.

METHODS

Retrospective chart review of 104 consecutive patients diagnosed with head and neck NTM at a tertiary paediatric hospital between January 1994 and December 2013 inclusive.

RESULTS

104 patients ranged in age between 8 months to 15 years (mean age 27 months) were reviewed and 97 patients were included in the final analysis. 6 patients excluded due to lack of follow-up and one excluded due to systemic immunocompromised condition. Sub-sites of NTM infections were submandibular (n=48, 46%), cervical (n=40, 38%), parotid (n=18, 17%) and submental (n=4, 4%). Some patients had more than one lesion so counted twice. Higher cure rates were demonstrated for primary excision (81%, p<0.01) versus incisional interventions (44%, p<0.01). Marginal mandibular nerve palsy following surgery was seen in 7 patients (7.2%). This was permanent in 4 patients (4%) and temporary in 3 patients (3%). All children who were complicated with marginal mandibular palsies had lesions in the submandibular region. The rate of palsy for submandibular disease alone was 15%, while 8% presented permanent palsy and 6% temporary. Marginal mandibular nerve palsy was more likely following excisional compared to incisional procedures (6 versus 1 patient, p<0.01). Hypertrophic scarring occurred in 7 patients: 3 patients following excision and 4 patients after an incisional procedure. One patient suffered long term spinal accessory nerve damage presented as winged scapula.

CONCLUSIONS

Excision of NTM provides better cure rates compared to incision although at the expense of long term post-surgical morbidity. Excision should probably be the first line of treatment when the risk for neural damage is low. Incision and drainage with or without antimycobacterial treatment may be the preferred option for at-risk sub-sites (submandibular or parotid) in order to reduce long term morbidity.

Detection of carotid artery calcification on the panoramic images of post-menopausal females is significantly associated with severe abdominal aortic calcification: a risk indicator of future adverse vascular events

OBJECTIVES

Outcome studies among post-menopausal females with calcified carotid artery plaque (CCAP) on their panoramic images have not been previously undertaken. We sought to compare the extent of abdominal aortic calcification (AAC) on lateral lumbar spine radiographs (LLSRs), among groups of females with (CCAP+) and without (CCAP-) carotid lesions on their panoramic images. "Severe" levels of AAC have previously been validated as a risk indicator of future adverse cardiovascular events.

METHODS

This cross-sectional case-control study included a "CCAP+ group" consisting of females more than 50 years of age having the carotid lesion diagnosed by their dentists and an atherogenic risk factor (age, body mass index, hypertension, diabetes and dyslipidaemia)-matched "CCAP- group". A physician radiologist, using the Framingham index, evaluated the LLSRs for the magnitude of AAC. Summary statistics for key variables were computed and conditional logistic regression techniques were considered.

RESULTS

Members of the CCAP+ group were significantly (p=0.038) more likely to demonstrate "severe" levels of AAC on their LLSRs than members of the CCAP group.

CONCLUSIONS

This is the first published study demonstrating that CCAP on panoramic images of post-menopausal females is significantly associated with "severe" levels of AACs on LLSRs independent of traditional risk factors. Given that these levels of AAC are a validated risk indicator of future myocardial infarction and stroke, dentists must evaluate the panoramic images of post-menopausal females for the presence of CCAP. Patients with carotid atheromas should be referred to their physicians for further evaluation given the systemic implications.

A cautionary tale: dealing with missing data in clinical trials for rheumatic diseases

OBJECTIVES

Missing data are found in nearly all clinical trials and it is important to use appropriate statistical techniques to analyse clinical trials with missing data. We discuss common statistical methods for tackling missing data and how to handle results when the analyses give different results.

METHODS

Using data from a placebo-controlled, randomised bovine Type I collagen (CI) study in diffuse cutaneous systemic sclerosis (dcSSc), we apply different statistical approaches to handling missing data. We also describe simple ways to ascertain the type of missing data in the data set, to the extent possible.

RESULTS

We examine eleven different methods to impute missing data. An analysis based on completers alone (complete case analysis and available case analysis) and the last observation carried forward (LOCF) methods require underlying assumptions which are rarely met in practice. Multiple imputation, mixed effects, and repeated measures try to account for the differences among patients and account for patient's specific response patterns, although the assumption that the missing data is directly related to the observed characteristics may well not be true. The joint likelihood based model combines the mixed effect model and logistic regression model to explicitly handle data not missing at random and so it is more realistic and potentially takes an additional step toward decreasing bias.

CONCLUSIONS

We discussed various ways of handling missing data and provide recommendations on how to arrive at a conclusion when different statistical approaches to analyse missing data analysis in clinical trials give conflicting answers.

Sequence memory based on coherent spin-interaction neural networks

Sequence information processing, for instance, the sequence memory, plays an important role on many functions of brain. In the workings of the human brain, the steady-state period is alterable. However, in the existing sequence memory models using heteroassociations, the steady-state period cannot be changed in the sequence recall. In this work, a novel neural network model for sequence memory with controllable steady-state period based on coherent spininteraction is proposed. In the proposed model, neurons fire collectively in a phase-coherent manner, which lets a neuron group respond differently to different patterns and also lets different neuron groups respond differently to one pattern. The simulation results demonstrating the performance of the sequence memory are presented. By introducing a new coherent spin-interaction sequence memory model, the steady-state period can be controlled by dimension parameters and the overlap between the input pattern and the stored patterns. The sequence storage capacity is enlarged by coherent spin interaction compared with the existing sequence memory models. Furthermore, the sequence storage capacity has an exponential relationship to the dimension of the neural network.

Pinning controllability of complex networks with community structure

In this paper, we study the controllability of networks with different numbers of communities and various strengths of community structure. By means of simulations, we show that the degree descending pinning scheme performs best among several considered pinning schemes under a small number of pinned nodes, while the degree ascending pinning scheme is becoming more powerful by increasing the number of pinned nodes. It is found that increasing the number of communities or reducing the strength of community structure is beneficial for the enhancement of the controllability. Moreover, it is revealed that the pinning scheme with evenly distributed pinned nodes among communities outperforms other kinds of considered pinning schemes.

Efficacies of two in-house indirect ELISAs for diagnosis of amoebic liver abscess

Entamoeba histolytica causes amoebic diarrhoea, colitis and liver abscess (ALA). Diagnosis of ALA is difficult, as most patients do not have simultaneous intestinal amoebic infection. At Hospital Universiti Sains Malaysia (HUSM), diagnosis of ALA relies on a combination of clinical findings, ultrasound examination of the liver and serodiagnosis using a commercial kit. In this study, two in-house indirect ELISAs were developed and evaluated. One of the in-house assays utilises E. histolytica crude soluble antigen (CSA) to detect serum IgG specific to the parasite whereas the other uses E. histolytica ether extract antigen (EEA). Preparation of CSA requires a sonicator to lyse the amoeba whereas EEA was prepared by chemically solubilizing the trophozoites. Based on the cut-off value of mean optical density + 3SD, CSA-ELISA showed 100% (24/24) sensitivity and 93.33% (210/225) specificity; while EEA-ELISA showed 91.67% (22/24) sensitivity and 95.11% (214/225) specificity. In conclusion, both the in-house indirect ELISAs were found to be efficacious for diagnosis of ALA; and the EEA is easier to prepare than the commonly used CSA.

An analytic criterion for generalized synchronization in unidirectionally coupled systems based on the auxiliary system approach

An analytic criterion is developed to investigate generalized synchronization (GS) in unidirectionally coupled systems based on the auxiliary system approach. The criterion is derived by transforming the existence problem of generalized synchronization into an eigenvalue problem. Numerical simulations show that the analytic criterion is almost as accurate as the response Lyapunov exponents method, and may provide an estimation of the threshold of strong generalized synchronization. A significant result can be deduced from our analysis that the more the number of equilibria of the unidirectionally coupled systems, the greater the chance of generalized synchronization, but the harder it may be for strong generalized synchronization to occur.

Laparoscopic sleeve gastrectomy: a novel procedure for weight loss

INTRODUCTION

Morbid obesity is associated with increased morbidity and mortality. Bariatric surgery offers morbidly obese individuals substantial and sustainable weight loss and reduction in obesity-related comorbidities. Laparoscopic sleeve gastrectomy (LSG) is a new restrictive procedure in bariatric surgery. We aimed to evaluate our experience with LSG with regard to its safety and feasibility and early weight loss.

METHODS

The surgical outcome, complications and early clinical results of all patients who underwent LSG at Singapore General Hospital were studied.

RESULTS

30 patients underwent LSG between December 2008 and October 2010. The mean preoperative weight of the patients was 113.4 (range 91.0-170.0) kg, while the mean body mass index (BMI) was 42.6 (range 33.0-60.0) kg/m². Diabetes mellitus was present in 39 percent of the patients, hypertension in 43 percent, hyperlipidaemia in 35 percent, obstructive sleep apnoea in 30 percent and osteoarthritis in 22 percent. The majority of patients had two or more obesity-related comorbidities (52 percent). Mean operative time was 142 (range 80-220) minutes and median duration of postoperative stay was three days. At two weeks, one, three and six months post operation, the mean BMI was 38.6 kg/m², 37.8 kg/m², 34.5 kg/m² and 30.8 kg/m², the mean percentage of excess weight loss was 17.7 percent, 23.3 percent, 40.9 percent and 56.7 percent, and absolute weight loss was 8.00 kg, 11.52 kg, 18.77 kg and 26.85 kg, respectively.

CONCLUSION

LSG is a promising procedure for surgical treatment of obesity, with good early weight loss and low morbidity.

Guideline on training and credentialing in endoscopic retrograde cholangiopancreatography

The aim of the Endoscopic Retrograde Cholangiopancreatography (ERCP) Working Group was to examine the issues of training, credentialing and quality control in ERCP in Singapore. Published guidelines and clinical trials concerning issues of training, complications and quality control in ERCP have been reviewed. The Working Group recommended that a trainee reach a minimum threshold of 200 cases before the assessment of competency. The target for achievement of competency was set at an 85 percent successful cannulation rate for native papilla. To perform advanced ERCP, endoscopists should have undergone dedicated training either in a recognised training centre or in conjunction with and under the guidance of a more experienced colleague, until technical competency is achieved. Precut should only be performed by endoscopists with experience and expertise in performing Levels II and III ERCP, who have been formally proctored. An audit of ERCP should examine parameters such as appropriate indication, success rates of selective cannulation, technical success rate of commonly performed procedures and procedure-related complications. To maintain technical competency, an individual should be performing ERCP on a regular basis. In conclusion, the innate risks of ERCP necessitate that all ERCP practitioners should be appropriately trained, practise within their expertise level and maintain regular practice in order to minimise risks and improve patient outcome.

Multiobjective synchronization of coupled systems

In this paper, multiobjective synchronization of chaotic systems is investigated by especially simultaneously minimizing optimization of control cost and convergence speed. The coupling form and coupling strength are optimized by an improved multiobjective evolutionary approach that includes a hybrid chromosome representation. The hybrid encoding scheme combines binary representation with real number representation. The constraints on the coupling form are also considered by converting the multiobjective synchronization into a multiobjective constraint problem. In addition, the performances of the adaptive learning method and non-dominated sorting genetic algorithm-II as well as the effectiveness and contributions of the proposed approach are analyzed and validated through the Rössler system in a chaotic or hyperchaotic regime and delayed chaotic neural networks.

Randomized controlled trial of standard versus high-dose intravenous omeprazole after endoscopic therapy in high-risk patients with acute peptic ulcer bleeding

Background

Rebleeding from peptic ulcers is a major contributor to death. This study compared standard (40-mg intravenous infusion of omeprazole once daily for 3 days) and high-dose (80-mg bolus of omeprazole followed by 8-mg/h infusion for 72 h) in reducing the rebleeding rate (primary endpoint), need for surgery, duration of hospital stay and mortality in patients with peptic ulcer bleeding after successful endoscopic therapy.

Methods

This was a single-institution prospective randomized controlled study based on a postulated therapeutic equivalence of the two treatments. All patients who had successful endoscopic haemostasis of a bleeding peptic ulcer (Forrest classification Ia, Ib, IIa or IIb) were recruited. Informed consent was obtained and patients were randomized to receive standard- or high-dose infusions of intravenous omeprazole.

Results

Two (3 per cent) of 61 patients in the high-dose group and ten (16 per cent) of 61 in the standard-dose group exhibited rebleeding, a difference of − 13 (95 per cent confidence interval − 25 to − 2) per cent. The upper limit of the one-sided confidence interval exceeded a predefined equivalence absolute difference of 16 per cent. Equivalence of standard- and high-dose omeprazole in preventing rebleeding was not demonstrated.

Conclusion

Intravenous standard-dose omeprazole was inferior to high-dose omeprazole in preventing rebleeding after endoscopic haemostasis for peptic ulcer bleeding. Registration number: NCT00519519 (http://www.clinicaltrials.gov).

Stimulation with type I collagen induces changes in gene expression in peripheral blood mononuclear cells from patients with diffuse cutaneous systemic sclerosis (scleroderma)

An autoantigenic role for collagen type I (CI) has been suggested previously in diffuse cutaneous systemic sclerosis (dcSSc). Whether CI is indeed capable of affecting the immune system in dcSSc is not known. Patients with early (3 years or less) or late (>3 years) dcSSc and healthy controls donated blood. Peripheral blood mononuclear cells (PBMC) were cultured with or without CI, and expression of genes known for their involvement in autoimmune and inflammatory processes was assessed using cDNA arrays; results were confirmed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay for selected genes. Patients with early and late dcSSc were similarly different from healthy controls in basal gene expression. When cultured with CI, PBMC from patients with early dcSSc differed from healthy controls in expression of 34 genes, whereas PBMC from patients with late dcSSc differed from healthy controls in expression of only 29 genes. Direct comparisons of matched PBMC samples cultured with and without CI revealed differences in expression of eight genes in healthy controls, of five genes in patients with early dcSSc, and no differences in patients with late dcSSc. Thus, PBMC from patients with dcSSc respond differently than do PBMC from healthy controls when cultured with CI. Exposure to CI in culture of PBMC from patients in the early stage of dcSSc in contrast to PBMC from patients with late-stage dcSSc evokes a greater degree of activation of immune-related genes, suggesting that CI is more dominant as an autoantigen in early versus late dcSSc.

Identification of Entamoeba histolytica trophozoites in fresh stool sample: comparison of three staining techniques and study on the viability period of the trophozoites

Entamoeba histolytica causes about 50 million infections worldwide with a death rate of over 100,000 annually. In endemic developing countries where resources are limited, microscopic examinations based on Wheatley trichrome staining is commonly used for diagnosis of intestinal amoebiasis. Other than being a time-consuming method, it must be performed promptly after stool collection as trophozoites disintegrate rapidly in faeces. The aim of this study was to compare the efficacies of Eosin-Y, Wheatley trichrome and Iodine stains in delineating the diagnostic features of the parasite, and subsequently to determine the suitable microscopy observation period for detection of erythrophagocytic and non-erythrophagocytic trophozoites spiked in semi-solid stool sample. Wheatley trichrome staining technique was performed using the standard method while the other two techniques were performed on the slides by mixing the respective staining solution with the spiked stool sample. One million of axenically cultured non-erythrophagocytic E. histolytica and erythrophagocytic E. histolytica were separately spiked into 2 g of fresh semisolid faeces. Percentage viability of the trophozoites in the spiked stool sample was determined at 30 minute intervals for eight hours using the 0.4% Trypan blue exclusion method. The results showed that Eosin-Y and Wheatley trichrome stained the karyosome and chromatin granules better as compared to Iodine stain. The percentage viability of non-erythrophagocytic trophozoites decreased faster than the erythrophagocytic form in the first 5 hours and both dropped to ~10% in the 6th hour spiked sample. In conclusion, Eosin-Y staining technique was found to be the easiest to perform, most rapid and as accurate as the commonly used Wheatley trichrome technique; Eosin-Y stained slide sealed with DPX could also be kept as a permanent record. A period not exceeding 6 hours after stool collection was found to be the most suitable in order to obtain good microscopy results of viable trophozoites.

Seroprevalence of anti-amoebic antibody among blood donors by indirect hemeagglutination assay

The screening for anti-amoebic antibody among a group of donors was to obtain negative control serum samples for an on-going antigen development assay in diagnosis of amoebic liver abscess. Out of 200 samples, 125 (62.5%) were negative, whereas 44 (21.5%) had IHA titer of less than 1:128 and 31 (16.0%) of the samples had significant IHA titers of 1:128 or more, in which 2 serum samples gave titers of 1:4096.

Organ-specific hemosiderosis and functional correlation in Chinese patients with thalassemia intermedia and hemoglobin H disease

We performed MRI assessment in 37 adult Chinese patients with thalassemia intermedia and hemoglobin H disease. Despite abnormal ferritin and liver T2*, only 5% of patients had cardiac hemosiderosis. The two patients with reduced ejection fraction had normal cardiac T2*. Half of the cases showed pituitary and pancreatic iron loading. Subclinical endocrine abnormalities (HOMA, insulin growth factor) showed correlation with pancreatic, pituitary, and cardiac MRI values. Prospective data with serial functional and imaging monitoring is needed to verify the utility for chelation to improve cardiac and endocrine function in this group of patients.

Spleen-preserving distal pancreatectomy

INTRODUCTION

Splenectomy is routinely performed in conventional distal pancreatectomies. Spleen removal with its possible sequelae of infections and haematological complications has prompted the development of spleen-preserving techniques. This study aimed to evaluate the safety and clinical outcomes of distal pancreatectomy with preservation of the spleen.

METHODS

A retrospective review of 24 consecutive patients who underwent spleen-preserving distal pancreatectomy in a tertiary care hospital was conducted.

RESULTS

There were 17 female and seven male patients, and the mean age was 47 (range 14-77) years. Median American Society of Anesthesiologists score was II (range I-III) . The indications were as follows : mucinous cystadenoma (n = 7), serous cystadenoma (n = 6), insulinoma (n = 3), intraductal papillary mucinous tumour (n = 2), pseudocyst (n = 3), papillary cystic adenoma (n = 1), neuroendocrine neoplasm (n = 1), and metastatic carcinoma of the thyroid (n = 1). Two patients developed postoperative pancreatic fistula and another two patients developed postoperative ileus with spontaneous resolution. Mean operative time was 172 (range 105-250) minutes. Mean length of postoperative hospital stay was 6.7 (range 5-11) days. There was no perioperative mortality in this series.

CONCLUSION

Spleen-preserving distal pancreatectomy can be safely performed with low morbidity, and should be considered in the surgical management of distal pancreatic disease.

Development and validation of a new method for measuring friction between skin and nonwoven materials

A new method for measuring the coefficient of friction between nonwoven materials and the curved surface of the volar forearm has been developed and validated. The method was used to measure the coefficient of static friction for three different nonwoven materials on the normal (dry) and over-hydrated volar forearms of five female volunteers (ages 18–44). The method proved simple to run and had good repeatability: the coefficient of variation (standard deviation expressed as a percentage of the mean) for triplets of repeat measurements was usually (80 per cent of the time) less than 10 per cent. Measurements involving the geometrically simpler configuration of pulling a weighted fabric sample horizontally across a quasi-planar area of volar forearm skin proved experimentally more difficult and had poorer repeatability. However, correlations between values of coefficient of static friction derived using the two methods were good ( R = 0.81 for normal (dry) skin, and 0.91 for over-hydrated skin). Measurements of the coefficient of static friction for the three nonwovens for normal (dry) and for over-hydrated skin varied in the ranges of about 0.3–0.5 and 0.9–1.3, respectively. In agreement with Amontons' law, coefficients of friction were invariant with normal pressure over the entire experimental range (0.1–8.2 kPa).

A magnetic resonance imaging study of iron overload in hemopoietic stem cell transplant recipients with increased ferritin levels

We performed a study of magnetic resonance imaging (MRI) assessment of hemosiderosis in the heart (T2/T2*), liver (T2*), pancreas (T2*), and pituitary gland (T2/T2*/SIR) in 20 hemopoietic stem cell transplant (HSCT) recipients (median peak ferritin levels 7615 pmol/L, range 3411 to 33000 pmol/L). MRI reading was abnormal in the heart (5%), liver (85%), pancreas (40%), and pituitary gland (55%). The heart T2 correlated with peak ferritin levels (P=.024), while the liver T2* correlated with current ferritin (P=.038) values only. Pancreatic T2* values correlated with pituitary T2 and signal intensity ratio values. The ejection fraction was abnormal in 10% of cases and did not correlate with ferritin level or heart T2. The peak liver enzymes correlated with peak ferritin (P=.025), but the current liver enzymes were mostly normal. Pancreatic assessments (fasting glucose, insulin, beta cell function, insulin reserve, and C-peptide) and pituitary growth hormone axis assessments (growth hormone, insulin growth factor-1, and insulin growth factor binding protein-3) were abnormal in 40% to 70% of cases. They were unrelated to pancreas or pituitary MRI values. Interestingly, endocrine assessments correlated with heart T2 values and peak (but not current) ferritin levels. We concluded that iron overload may contribute to organ damage after HSCT, and MRI assessment may be useful in its detection and treatment monitoring.

Clinical spectrum and surgical management of acute mesenteric ischaemia in Singapore

INTRODUCTION

Acute mesenteric ischaemia (AMI) is a surgical emergency with a dismal prognosis. Much of the literature concerning this condition is from the West. This study aims to present a single-centre Asian experience of management of patients with AMI and the immediate outcome following surgical treatment.

METHODS

This is a retrospective study of patients managed for AMI in our department between 1990 and 2003. The data was obtained from a prospectively-collected surgical data base as well as from clinical case records.

RESULTS

65 patients were managed by our department for AMI over 14 years. The median age of this patient group was 69 years, with a high prevalence of cardiovascular diseases. The majority of patients presented with abdominal pain, distension and vomiting. The commonest subtype of AMI was caused by mesenteric arterial occlusion; this subtype also had the highest in-hospital mortality. Our overall in-hospital mortality for all 65 patients was 55.4 percent.

CONCLUSION

Clinical suspicion, especially in a patient with the relevant risk factors, remains the mainstay of appropriate early management of AMI. Our patient demographics, coexistent diseases and commonest subtype of AMI were similar to that reported in the Western literature. In this paper, we also suggest a management algorithm for patients with suspected AMI.