Adoption of analytical technologies for verification of authenticity of halal foods - a review

Halal authentication has become essential in the food industry to ensure food is free from any prohibited ingredients according to Islamic law. Diversification of food origin and adulteration issues have raised concerns among Muslim consumers. Therefore, verification of food constituents and their quality is paramount. From conventional methods based on physical and chemical properties, various diagnostic methods have emerged relying on protein or DNA measurements. Protein-based methods that have been used in halal detection including electrophoresis, chromatographic-based methods, molecular spectroscopy and immunoassays. Polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) are DNA-based techniques that possess better accuracy and sensitivity. Biosensors are miniatured devices that operate by converting biochemical signals into a measurable quantity. CRISPR-Cas is one of the latest novel emerging nucleic acid detection tools in halal food analysis as well as quantification of stable isotopes method for identification of animal species. Within this context, this review provides an overview of the various techniques in halal detection along with their advantages and limitations. The future trend and growth of detection technologies are also discussed in this review.

Biosensor DNA Voltametrik Berasaskan Nanozarah Emas Bersalut Elektrod Bercetak Skrin Karbon untuk Pengesanan DNA Organisma Terubahsuai Genetik (GMO)

Genosensor voltametri untuk pengesanan DNA organisma terubah suai genetik (GMO) telah dibangunkan berasaskan nanozarah emas (AuNPs) dan elektrod pes karbon bercetak skrin (SPE). AuNPs telah dipegunkan pada SPE melalui kaedah pertumbuhan perantara benih dan dicirikan dengan mikroskop elektron pengimbasan (SEM). 6-Mercapto-1-heksanol (MCH) telah digunakan untuk membentuk lapisan mono prob DNA rantai tunggal (ssDNA) pada SPE terubah suai AuNPs (AuNPs-SPE). Biosensor GMO telah dioptimumkan secara elektrokimia menggunakan oligonukleotida sintetik melalui teknik voltametri denyutan pembezaan (DPV). Biosensor GMO yang dioptimumkan kemudiannya digunakan untuk menganalisis sampel sebenar bagi pengesanan khusus urutan DNA dalam virus mozek kubis bunga, iaitu gen CaMV 35S. Isyarat penghibridan DNA dipantau berdasarkan arus puncak pengoksidaan penunjuk redoks asid monosulfonat antrakuinona (AQMS) semasa interkalasinya ke dalam dupleks DNA. Biosensor GMO memberi rangsangan secara linear kepada DNA terubah suai genetik (GM) antara 0.1 nM dan 300.0 nM dan had pengesanan diperoleh pada 0.06 nM. Sisihan piawai relatif (RSD) kebolehulangan biosensor GMO dianggarkan pada 6.7-7.8%. Biosensor GMO berasaskan AuNPs mempamerkan prestasi pengesanan DNA yang lebih baik daripada segi julat linear dinamik dan had pengesanan berbanding dengan biosensor GMO elektrokimia yang dilaporkan sebelum ini. Biosensor DNA elektrokimia ini menyediakan satu platform pengesanan pakai buang untuk aplikasi dalam ujian bahan GMO.

Loop-Mediated Isothermal Amplification (LAMP) as a Promising Point-of-Care Diagnostic Strategy in Avian Virus Research

Simple Summary

Many of the existing screening methods of avian viruses depend on clinical symptoms and pathological gross examinations that still necessitate confirmatory microscopic testing. Confirmation of a virus is often conducted at centralized laboratories that are well-equipped with instruments for virus isolation, hemagglutinin inhibition, virus neutralization, ELISA, PCR and qPCR. These assays are known for their great accuracy and sensitivity, and hence are set as standard practices. Nevertheless, limitations arise due to the time, cost and on-site applicability. As the technology progresses, molecular diagnostics should be more accessible to isolated areas and even practicable for use by non-skilled personnel such as farmers and private breeders. One of the point-of-care diagnostic strategies to consider for such matters is loop-mediated isothermal amplification (LAMP).

Abstract

Over the years, development of molecular diagnostics has evolved significantly in the detection of pathogens within humans and their surroundings. Researchers have discovered new species and strains of viruses, while mitigating the viral infections that occur, owing to the accessibility of nucleic acid screening methods such as polymerase chain reaction (PCR), quantitative (real-time) polymerase chain reaction (qPCR) and reverse-transcription qPCR (RT-qPCR). While such molecular detection methods are widely utilized as the benchmark, the invention of isothermal amplifications has also emerged as a reliable tool to improvise on-field diagnosis without dependence on thermocyclers. Among the established isothermal amplification technologies are loop-mediated isothermal amplification (LAMP), recombinant polymerase amplification (RPA), strand displacement activity (SDA), nucleic acid sequence-based amplification (NASBA), helicase-dependent amplification (HDA) and rolling circle amplification (RCA). This review highlights the past research on and future prospects of LAMP, its principles and applications as a promising point-of-care diagnostic method against avian viruses.

Integration of advanced technologies for plant variety and cultivar identification

Identification of plant variety and cultivar is pivotal in the agricultural sector due to the abundance of plant varieties and cultivars developed in many crop species. However, plant variety and cultivar identification via basic morphological features is problematic and challenging when differentiating closely related species not only due to their limited differences but also due to technical limitations of the process being time-consuming, labour-intensive and costly, and statistically imprecise information being available due to phenotypic plasticity. Therefore, it is imperative to have rapid and highly efficient techniques to mitigate these limitations. This review provides an overview and summarization of the development and application of molecular markers such as Random Amplified Polymorphic DNA (RAPD), Restriction Fragment Length Polymorphism (RFLP), Simple Sequence Repeats (SSR), Inter-simple sequence repeats (ISSR), Amplified Fragment Length Polymorphism (AFLP), Single nucleotide polymorphism (SNP) and DNA barcoding, High-resolution melting (HRM) and biosensor technology as potential tools in the identification of plant variety and cultivar.

A turning point: Head and neck cancer patients' exercise preferences and barriers before and after participation in an exercise intervention

This study examined the exercise barriers and preferences of head and neck cancer (HNC) survivors in relation to exercise experience. Participants (n = 22; 46.8% response rate) completed retrospective self-report questionnaires on demographic and medical information, exercise barriers and preferences. A subset of participants then completed semi-structured interviews (n = 18). Participants had previously engaged in the ENHANCE trial during, or immediately following, radiation treatment, an average of 22.1 ± 5.8 months before. Retrospective questionnaires revealed that before ENHANCE participation, lack of interest and time were the primary exercise barriers. After participation, there was a significant decrease in typical barriers including lack of interest (p = .008), exercise not a priority (p = .039) and exercise not in routine (p = .004). Number of barriers experienced after ENHANCE participation was negatively correlated with age, quality of life and minutes of resistance exercise training per week. After ENHANCE participation, significant increases were found in preference for exercising at a cancer centre (p = .031) and with other cancer survivors (p = .016). Four higher order themes emerged inductively from interview data analysis pertaining to preferences (i.e., class format) and three higher order themes regarding barriers (physical, psychological and external). By investigating participants' perspectives after ENHANCE participation, key factors for effective HNC exercise programme design were identified.

Advanced DNA-Based Point-of-Care Diagnostic Methods for Plant Diseases Detection

Diagnostic technologies for the detection of plant pathogens with point-of-care capability and high multiplexing ability are an essential tool in the fight to reduce the large agricultural production losses caused by plant diseases. The main desirable characteristics for such diagnostic assays are high specificity, sensitivity, reproducibility, quickness, cost efficiency and high-throughput multiplex detection capability. This article describes and discusses various DNA-based point-of care diagnostic methods for applications in plant disease detection. Polymerase chain reaction (PCR) is the most common DNA amplification technology used for detecting various plant and animal pathogens. However, subsequent to PCR based assays, several types of nucleic acid amplification technologies have been developed to achieve higher sensitivity, rapid detection as well as suitable for field applications such as loop-mediated isothermal amplification, helicase-dependent amplification, rolling circle amplification, recombinase polymerase amplification, and molecular inversion probe. The principle behind these technologies has been thoroughly discussed in several review papers; herein we emphasize the application of these technologies to detect plant pathogens by outlining the advantages and disadvantages of each technology in detail.

Isoprenylcysteine carboxylmethyltransferase is critical for malignant transformation and tumor maintenance by all RAS isoforms

Despite extensive effort, there has been limited progress in the development of direct RAS inhibitors. Targeting isoprenylcysteine carboxylmethyltransferase (ICMT), a unique enzyme of RAS post-translational modification, represents a promising strategy to inhibit RAS function. However, there lacks direct genetic evidence on the role of ICMT in RAS-driven human cancer initiation and maintenance. Using CRISPR/Cas9 genome editing, we have created Icmt loss-of-function isogenic cell lines for both RAS-transformed human mammary epithelial cells (HME1) and human cancer cell lines MiaPaca-2 and MDA-MB-231 containing naturally occurring mutant KRAS. In both in vitro and in vivo tumorigenesis studies, Icmt loss-of-function abolishes the tumor initiation ability of all major isoforms of mutant RAS in HME1 cells, and the tumor maintenance capacity of MiaPaca-2 and MDA-MB-231 cells, establishing the critical role of ICMT in RAS-driven cancers.

Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes

Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics.

Field Demonstration of a Multiplexed Point-of-Care Diagnostic Platform for Plant Pathogens

Effective disease management strategies to prevent catastrophic crop losses require rapid, sensitive, and multiplexed detection methods for timely decision making. To address this need, a rapid, highly specific and sensitive point-of-care method for multiplex detection of plant pathogens was developed by taking advantage of surface-enhanced Raman scattering (SERS) labeled nanotags and recombinase polymerase amplification (RPA), which is a rapid isothermal amplification method with high specificity. In this study, three agriculturally important plant pathogens (Botrytis cinerea, Pseudomonas syringae, and Fusarium oxysporum) were used to demonstrate potential translation into the field. The RPA-SERS method was faster, more sensitive than polymerase chain reaction, and could detect as little as 2 copies of B. cinerea DNA. Furthermore, multiplex detection of the three pathogens was demonstrated for complex systems such as the Arabidopsis thaliana plant and commercial tomato crops. To demonstrate the potential for on-site field applications, a rapid single-tube RPA/SERS assay was further developed and successfully performed for a specific target outside of a laboratory setting.

Adenoid cystic carcinoma of head and neck: clinical predictors of outcome from a Canadian centre

OBJECTIVES

Adenoid cystic carcinoma (acc) is often treated with surgery, with or without adjuvant radiation therapy (rt). We evaluated disease characteristics, treatments, and potentially prognostic variables in patients with acc.

METHODS

Our retrospective analysis considered consecutive cases of acc presenting at a tertiary care hospital between 2000 and 2014. Factors predictive of overall survival (os) and disease-free survival (dfs) were identified by univariate analysis.

RESULTS

The 60 patients analyzed had a mean age of 58 years (range: 22-88 years), with a 2:1 female:male ratio. Tumour locations included the major salivary glands (40% parotid, 17% submandibular and sublingual), the oro-nasopharyngeal cavity (27%), and other locations (16%). Of the 60 patients, 35 (58%) received surgery with adjuvant rt; 12 (20%), rt only; 13 (22%), surgery only. Of 18 patients (30%) who experienced a recurrence within 5 years, 3 (5%) developed local recurrence only, and the remaining 15 (25%), distant metastasis. The 5-year os and dfs were 64.5% [95% confidence interval (ci): 45.9% to 78.1%] and 46.2% (95% ci: 29.7% to 61.2%) respectively. In patients without recurrence, 5-year os was 77% (95% ci: 52.8% to 89.9%), and in patients with recurrence, it was 42.7% (95% ci: 15.8% to 67.6%). Patients treated with rt only had a 5-year os of 9.2%. Predictors of 5-year dfs were TNM stage, T stage, nodal status, treatment received, and margin status; age, nodal status, treatment received, and margin status predicted 5-year os.

CONCLUSIONS

Despite surgery and rt, one third of patients with acc experience distant recurrence. Patients whose tumours are not amenable to surgery have a poor prognosis, indicating a need for alternative approaches to improve outcomes.

Angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in a Chinese paediatric population

OBJECTIVE

To identify specific angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in Chinese paediatric patients.

DESIGN

Retrospective cross-sectional observational study.

SETTING

Four locoregional tertiary neurosurgical centres in Hong Kong: Queen Elizabeth Hospital, Tuen Mun Hospital, Kwong Wah Hospital, and Pamela Youde Nethersole Eastern Hospital.

PATIENTS

Patients aged 18 years or younger who underwent pretreatment digital subtraction angiography for brain arteriovenous malformation between 1 January 2005 and 31 July 2013 were included. Patients were divided into haemorrhagic and non-haemorrhagic groups based on the initial presentation. Pretreatment digital subtraction angiographies were independently reviewed by two experienced neuroradiologists.

MAIN OUTCOME MEASURES

The following parameters were evaluated for their association with haemorrhagic presentation by univariate and multivariate analyses: nidus location, nidus size, nidus morphology (diffuse or compact); origin and number of arterial feeders; venous drainage; number of draining veins; presence of aneurysms, venous varices, and venous stenosis.

RESULTS

A total of 67 children and adolescents (28 male, 39 female) with a mean age of 12 years were included. Of them, 52 (78%) presented with haemorrhage. Arteriovenous malformation size (P=0.004) and morphology (P=0.05) were found to be associated with haemorrhagic presentation by univariate analysis. Small arteriovenous malformation nidus size and diffuse nidal morphology were identified as independent risk factors for haemorrhage by multivariate analysis.

CONCLUSION

Smaller arteriovenous malformation size and diffuse nidal morphology are angiographic factors independently associated with haemorrhagic presentation. Bleeding risk is important in determining the therapeutic approach (aggressive vs conservative) and timeframe, particularly in paediatric patients.

Re-purposing bridging flocculation for on-site, rapid, qualitative DNA detection in resource-poor settings

Developing molecular diagnostics in resource-poor settings is challenging. As such, we purpose-built a novel bridging flocculation assay for qualitative evaluation of isothermally amplified DNA by naked eye. The flocculation assay was dependent on pH, DNA polymer amounts and lengths. The method was first applied to the rapid and sensitive detection of important plant pathogens and subsequently extended to other pathogens across the animal kingdom to demonstrate the wide applications of our approach.

Molecular inversion probe: a new tool for highly specific detection of plant pathogens

Highly specific detection methods, capable of reliably identifying plant pathogens are crucial in plant disease management strategies to reduce losses in agriculture by preventing the spread of diseases. We describe a novel molecular inversion probe (MIP) assay that can be potentially developed into a robust multiplex platform to detect and identify plant pathogens. A MIP has been designed for the plant pathogenic fungus Fusarium oxysporum f.sp. conglutinans and the proof of concept for the efficiency of this technology is provided. We demonstrate that this methodology can detect as little as 2.5 ng of pathogen DNA and is highly specific, being able to accurately differentiate Fusarium oxysporum f.sp. conglutinans from other fungal pathogens such as Botrytis cinerea and even pathogens of the same species such as Fusarium oxysporum f.sp. lycopersici. The MIP assay was able to detect the presence of the pathogen in infected Arabidopsis thaliana plants as soon as the tissues contained minimal amounts of pathogen. MIP methods are intrinsically highly multiplexable and future development of specific MIPs could lead to the establishment of a diagnostic method that could potentially screen infected plants for hundreds of pathogens in a single assay.

Paediatric vesicoureteric reflux imaging: where are we? Novel ultrasound-based voiding urosonography

Vesicoureteric reflux is an important association of paediatric urinary tract infection. Fluoroscopic micturating cystourethrography and radionuclide cystography have been employed for detecting and grading vesicoureteric reflux. However, both modalities involve ionising radiation, which can pose significant radiation risk to growing children. They also have a lower detection rate due to intermittent fluoroscopic technique in micturating cystourethrography, and lower spatial resolution in radionuclide cystography. Therefore, newer radiation-free ultrasound-based contrast-enhanced voiding urosonography has been developed in Europe for 15 years. This article aimed to summarise the current literature and discuss the first local pilot study in our institution on detection of vesicoureteric reflux by contrast-enhanced voiding urosonography. Contrast-enhanced voiding urosonography is a valid alternative to micturating cystourethrography in assessing vesicoureteric reflux, based on its superior diagnostic performance, reliability, safety, feasibility, and radiation safety for children. Therefore, it should be incorporated in the guideline for investigating paediatric urinary tract infection.

Use of the INNO-LIA syphilis score assay in the resolution of discordant positive screening enzyme immunoassay results for the serological diagnosis of syphilis

We studied the use of the INNO-LIA syphilis score assay in the resolution of discordant positive screening results of the Murex ICE Syphilis enzyme immunoassay (EIA) with the confirmatory results of both the Serodia Treponema pallidum particle agglutination (TPPA) and the fluorescent treponemal antibody-absorption (FTA-Abs) assays, for the serological diagnosis of syphilis. This was an observational study on the serum samples received by the Syphilis Laboratory, Hong Kong, during the period from January 2006 to December 2012. A total of 801 serum samples with discordant positive screening EIA results were used. Consensus results of such serum samples were derived from results of the EIA, TPPA and FTA-abs assays. The age range of the individuals was 14 to 104 years (median of 52). There were 369 males and 432 females. Of 378 serum samples, 139 showed agreement among positive results, 23 of 310 showed agreement among indeterminate results and 277 of 465 showed agreement among negative results. The proportions of agreement among positive, indeterminate and negative results were 0.37 (95% CI 0.32–0.42), 0.07 (95% CI 0.05–0.11) and 0.60 (95% CI 0.55–0.64), respectively; kappa 0.55 (95% CI 0.49–0.60). There were 60 serum samples with positive consensus results but negative INNO-LIA syphilis score results and 10 with negative consensus results but positive INNO-LIA syphilis score results. Although the INNO-LIA syphilis score assay can be considered a valid alternative confirmatory test for the serological diagnosis of syphilis, the present study showed that its use in the resolution of discordant positive screening EIA results was moderate. A more extensive characterization of serum samples with discordant reactive screening treponemal test results is necessary.

Hospitalisation associated with the 2009 H1N1 pandemic and seasonal influenza in Hong Kong, 2005 to 2010

Reliable estimates of the morbidity burden caused by the 2009 pandemic influenza (pH1N1) are important for assessing the severity of the pandemic. Poisson regression models were fitted to weekly numbers of cause-specific hospitalisation in Hong Kong from 2005 to 2010. Excess hospitalisation associated with the 2009 pandemic and seasonal influenza was derived from the model by incorporating the proxy variables of weekly proportions of specimens positive for the pandemic influenza A(H1N1)pdm09, seasonal influenza A (subtypes H3N2 and H1N1) and B viruses. Compared with seasonal influenza, pH1N1 influenza was associated with higher hospitalisation rates for acute respiratory disease (ARD) among children younger than 18 years and adults aged between 18 and 64 years, but among the elderly aged 65 years and older the hospitalisation rates were lower for pH1N1 than for seasonal H3N2 and H1N1 influenza. Hospitalisation rates for chronic diseases associated with pH1N1 influenza were generally higher than those associated with seasonal influenza. The reported hospitalised cases with laboratory-confirmed pandemic infections accounted for only 16% of pH1N1 influenza-associated hospitalisations for ARD in the age group 75 years and older, and 5‒66% of hospitalisations for chronic diseases in those older than 40 years. The 2009 H1N1 influenza pandemic was associated with a dramatically increased risk of hospitalisation among children and young adults. The morbidity burden of pandemic was underreported in old people and in those with chronic conditions.

Hospitalisation associated with the 2009 H1N1 pandemic and seasonal influenza in Hong Kong, 2005 to 2010

Reliable estimates of the morbidity burden caused by the 2009 pandemic influenza (pH1N1) are important for assessing the severity of the pandemic. Poisson regression models were fitted to weekly numbers of cause-specific hospitalisation in Hong Kong from 2005 to 2010. Excess hospitalisation associated with the 2009 pandemic and seasonal influenza was derived from the model by incorporating the proxy variables of weekly proportions of specimens positive for the pandemic influenza A(H1N1)pdm09, seasonal influenza A (subtypes H3N2 and H1N1) and B viruses. Compared with seasonal influenza, pH1N1 influenza was associated with higher hospitalisation rates for acute respiratory disease (ARD) among children younger than 18 years and adults aged between 18 and 64 years, but among the elderly aged 65 years and older the hospitalisation rates were lower for pH1N1 than for seasonal H3N2 and H1N1 influenza. Hospitalisation rates for chronic diseases associated with pH1N1 influenza were generally higher than those associated with seasonal influenza. The reported hospitalised cases with laboratory-confirmed pandemic infections accounted for only 16% of pH1N1 influenza-associated hospitalisations for ARD in the age group 75 years and older, and 5?66% of hospitalisations for chronic diseases in those older than 40 years. The 2009 H1N1 influenza pandemic was associated with a dramatically increased risk of hospitalisation among children and young adults. The morbidity burden of pandemic was underreported in old people and in those with chronic conditions.

Infantile cortical hyperostosis (Caffey disease): a possible misdiagnosis as physical abuse

Infantile cortical hyperostosis (Caffey disease) is a rare self-limiting inflammatory bony disease of early infancy. We report a 1-month-old Chinese boy with Caffey disease who presented with painful swelling over his shins bilaterally. Physical abuse was initially suspected, but the radiological findings of periosteal thickening over multiple bones (particularly the mandible), symmetrical involvement, diaphyseal involvement with sparing of the epiphysis, made Caffey disease a likely diagnosis. This report highlights that infantile cortical hyperostosis is an important differential diagnosis for children suspected of being abused, and clinicians should have a high index of suspicion to avoid misdiagnosis.

A prospective, randomised, double-blinded trial to study the efficacy of topical tocotrienol in the prevention of hypertrophic scars

BACKGROUND

Despite widespread beliefs regarding the use of topical tocotrienol in the prevention of hypertrophic scars, there is very little evidence from well controlled and randomised clinical trials to justify its benefits for surgical scars.

OBJECTIVE

This study was conducted to evaluate the efficacy of topical tocotrienol in preventing the development of hypertrophic scars.

METHODS

A prospective, randomised, double-blinded study was performed on 122 patients with recently healed (<2 weeks) surgical scars, who were randomised into either a treatment group with 5% topical tocotrienol or a placebo group. The patients were required to apply the preparation to their scars twice a day for 6 weeks starting at 2 weeks after surgery. Assessments of the scars were performed at weeks 0, 2, 6 and 16 following the onset of topical application using three methods: a clinical assessment using the Patient and Observer Scar Assessment Scale (POSAS), a photographic scar assessment by two independent assessors using a visual analogue scale and laser Doppler imaging (LDI). Data analysis was performed on 85 patients (tocotrienol group: 45 patients; placebo group: 40 patients), who had completed four assessments.

RESULTS

There was no statistically significant difference in scar parameters between the tocotrienol and the placebo groups in the POSAS, photographic scar assessment or mean flux of LDI (p>0.05) categories. The mean LDI flux showed a decreasing trend over time, which was positively correlated with vascularity (correlation coefficient=0.325, p=0.008) and total scores (correlation coefficient=0.248, p=0.034) of the observer scar assessment scale on week 0. No significant adverse effect was observed.

CONCLUSIONS

Twice-daily application of 5% topical tocotrienol had no significant effect on the appearance and vascularity of scars over 4 months post-surgery. LDI has a promising role as a scar assessment tool.

Comparative evaluation of the INNO-LIA syphilis score and the MarDx Treponema pallidum immunoglobulin G Marblot test assays for the serological diagnosis of syphilis

We evaluated the performance of two immunoblot assays: the INNO-LIA Syphilis Score (LIA) and the MarDx T. pallidum IgG Marblot Test (TWB), as compared with that of the Murex ICE Syphilis enzyme immunoassay (EIA), the Serodia Treponema pallidum particle agglutination (TPPA) assay and the fluorescent treponemal antibody-absorption (FTA-abs) assay, for the serological diagnosis of syphilis using serum samples of 135 attendees of the social hygiene clinics of the Department of Health in Hong Kong newly diagnosed with syphilis and provided with clinical stages (39 in primary, 20 in secondary, 18 in early latent and 58 in latent of unknown duration) and of 43 normal healthy subjects between October and December 2004. The differences in the overall sensitivities of the LIA assay and the EIA/TPPA/FTA-abs assays were not statistically significant ( P > 0.05) whereas the overall sensitivity of the TWB assay was significantly lower ( P < 0.05) than the overall sensitivities of the EIA, the TPPA and the FTA-abs assays. The LIA assay had an overall sensitivity of 94.1% (95% CI 88.7–97.0%) whereas the TWB assay 65.2% (95% CI 56.8–72.7%). Both the LIA and the TWB assays have a specificity of 100%. When consensus results were derived from the most predominant results of the EIA, the TPPA and the FTA-abs assays, the LIA assay had a positive agreement with the consensus results of 98.5% (95% CI 94.5–99.6%) whereas the TWB assay 68.2% (95% CI 59.8–75.6%). Therefore, the LIA assay performed significantly better ( P < 0.05) than the TWB assay. The LIA assay can be considered to be a valid alternative confirmatory test for the serological diagnosis of syphilis.

Myocardial rupture associated with bolus injection of contrast medium during computed tomographic study in a patient with acute myocardial infarction: a rare but lethal complication

Well-documented potential cardiovascular complications associated with the use of contrast media include bradycardia, hypotension, arrhythmia, and conduction disturbances. Rupture of the myocardium after acute myocardial infarction is a known cause of death, but has yet to be recognised as a potential complication of the use of a bolus injection of contrast medium. On the contrary, contrast-enhanced computed tomographic studies have been performed widely for the diagnosis and evaluation of myocardial infarction. We report a case of complicated myocardial rupture after a single bolus injection of contrast medium during a computed tomographic study in an elderly woman with acute myocardial infarction, which led to cardiac tamponade and rapid death. Although rare, this should alert us to the need for cautious use of contrast medium in patients with acute myocardial infarction.

The role of biofilms and protozoa in Legionella pathogenesis: implications for drinking water

Current models to study Legionella pathogenesis include the use of primary macrophages and monocyte cell lines, various free-living protozoan species and murine models of pneumonia. However, there are very few studies of Legionella spp. pathogenesis aimed at associating the role of biofilm colonization and parasitization of biofilm microbiota and release of virulent bacterial cell/vacuoles in drinking water distribution systems. Moreover, the implications of these environmental niches for drinking water exposure to pathogenic legionellae are poorly understood. This review summarizes the known mechanisms of Legionella spp. proliferation within Acanthamoeba and mammalian cells and advocates the use of the amoeba model to study Legionella pathogenicity because of their close association with Legionella spp. in the aquatic environment. The putative role of biofilms and amoebae in the proliferation, development and dissemination of potentially pathogenic Legionella spp. is also discussed. Elucidating the mechanisms of Legionella pathogenicity development in our drinking water systems will aid in elimination strategies and procedural designs for drinking water systems and in controlling exposure to Legionella spp. and similar pathogens.

In vitro cytotoxicology model of oligo-chitosan and n, o-carboxymethyl chitosan using primary normal human epidermal keratinocyte cultures

Chitosan (beta-1, 4-D-glucosamine) is a deacetylated form of chitin with excellent biological properties in wound management. The natural properties of chitosan have the physical and chemical limitations to be widely used in biomedical fields. The improvement of the physical and chemical properties of chitosan with some additional chemicals will alter its biocompatibility. Therefore, the biological attribute of the modified chitosan must be evaluated. In this study, the cytotoxicity of oligo-chitosan (OC) and N, O- carboxymethyl-chitosan (NO-CMC) derivatives (O-C 1%, O-C 5%, NO-CMC 1% and NO-CMC 5%) was evaluated using primary normal human epidermal keratinocyte (pNHEK) cultures as an in vitro toxicology model at standardized cell passages (fourth passages). 3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl tetrazolium bromide (MTT) was used as a cell viability assay. The O-C 1% is one of the most compatible chitosan derivatives because it steadily sustained >70% of viable cells until 72 hr post-treatment. This was followed by O-C 5%, NO-CMC 5% and NO-CMC 1%. Therefore, oligo-chitosan had the ideal properties of a biocompatible material compared to N, O- carboxymethyl-chitosan in this study.

Surgical confirmation of ProstaScint abnormalities in two patients with high risk prostate cancer

We describe our initial experience using ProstaScint scanning in addition to conventional imaging modalities for staging of high risk prostate cancer. Using our protocol, ProstaScint images detected abnormalities in pelvic lymph nodes not seen on CT scan or magnetic resonance imaging (MRI) in two patients. Subsequent surgical pelvic lymphadenectomy confirmed these abnormalities. Further patients will be accrued on this study to estimate the sensitivity and specificity of ProstaScint scanning.

Enhanced accuracy of needle placement in horizontal stereotactic core biopsy by a plastic slot

Horizontal stereotactic core biopsy can be used in the investigation of clinically occult mammographic abnormalities especially when breast thickness is less than 3 cm. We designed a 6-mm plastic slot that can be inserted between the bushing and the biopsy gun to enhance the accuracy of needle placement within the lesion. With this device, the centre of the lesion can be targeted at the centre of the biopsy trough. We advocate the use of this piece of small, simple and inexpensive instrument in every case of horizontal stereotactic core biopsy.

Primary Swenson pull-through compared with multiple-stage pull-through in the neonate

BACKGROUND

In Hirschsprung's disease, the trend has been for earlier performance of definitive surgery. In our institution, primary Swenson pull-through has become the preferred procedure.

METHODS

Retrospective review of the patients treated for Hirschsprung's disease from January 1988 through March 1998 was performed. Sixty-five patients were identified. Median values, analysis of variance and x2 were used for comparisons.

RESULTS

The multiple-stage group (M, n = 47) was similar to the primary group (P, n = 18) for gestational age (40 v 39 weeks), time to meconium passage (37.9 v 35.5 hours), and age at diagnosis (median, M 27 vP 3.5 days). Age (median, M 268 vP 5 days) and weight (mean, M 9.4 v P 3.7 kg; P < .001) at pull-through were lower in the primary group. Length of stay (LOS) was lower in the primary group (mean, M 40.8 vP 20.3 days; P < .05). Operating time for pull-through was decreased in P (mean, M 305.2 v P 272.2 minutes; P = .02). Total complications were lower in the primary group (P = .03), with no differences in mortality or enterocolitis rates.

CONCLUSIONS

At our institution there were no increases in total complications or enterocolitis in the group undergoing primary Swenson. Primary pull-through is a viable option for the treatment of Hirschsprung's disease.

Large needle core biopsy--avoidance of biopsy table bombardment by the biopsy needle in stereotactic guided breast biopsy

Table bombardment by automated biopsy needle is an occasional technical problem during stereotactic core biopsy of the breast. It is most commonly encountered in small breasts and when lesions are close to the biopsy table. A reference chart is devised for stereotactic core biopsy using an add-on erect stereotactic biopsy table and automated spring-loaded biopsy gun. The chart serves as a reference for pre-biopsy assessment of the feasibility of core biopsy in the vertical approach due to the constraints of lesion depth and breast thickness. It allows easy and quick reference for the required needle length input for the stereotactic system to prevent table bombardment.

Orbital lymphoma: results of radiation therapy

Orbital lymphoma is a rare presentation of non-Hodgkin's lymphoma. Treatment with radiotherapy is well-established. Twenty cases of orbital lymphoma treated at the Singapore General Hospital with radiation therapy were reviewed. All patients had improvement of their initial presenting symptoms and complete remission after radiation. Long-term local control was achieved in 17 of 20 (85%) of the treated orbits.

Inhibition of rat peritoneal mast cell exocytosis by frusemide: a comparison with disodium cromoglycate

Among the loop diuretics, frusemide possesses unique airway protective activities which may be due to the inhibition of airway inflammatory cells such as the mast cell. We previously reported that frusemide and disodium cromoglycate (DSCG) demonstrated a similar profile of inhibitory activities against histamine release from rat peritoneal mast cells activated by various stimuli which increased intracellular calcium via different routes. Furthermore, the inhibitory activities of both compounds demonstrated marked tachyphylaxis and we hence postulated that frusemide and DSCG might share the same mechanism of action which involves the prevention of extracellular calcium influx into the mast cell cytoplasm. The present study confirmed the postulation by (a) demonstrating that cross-tachyphylaxis exists between the two compounds and (b) extending the observations on histamine release to the influx of extracellular calcium (45Ca) into rat peritoneal mast cells.