A Bilayer Method for Measuring Toughness and Strength of Dental Ceramics

The ever-increasing usage of ceramic materials in restorative dentistry necessitates a simple and effective method to evaluate flexural strength σF and fracture toughness KC. We propose a novel method to determine these quantities using a bilayer specimen composed of a brittle plate adhesively bonded onto a transparent polycarbonate substrate. When this bilayer structure is placed under spherical indentation, tunneling radial cracks initiate and propagate in the lower surface of the brittle layer. The failure analysis is based on previous theoretical relationships, which correlate σF with the indentation force P and layer thickness d, and KC with P and mean length of radial cracks. This work examines the accuracy and limitations of this approach using a wide range of contemporary dental ceramic materials. The effect of layer thickness, indenter radius, load level, and length and number of radial cracks are carefully examined. The accuracy of the predicted σF and KC is similar to those obtained with other concurrent test methods, such as biaxial flexure and 3-point bending (σF), and bending specimens with crack-initiation flaws (KC). The benefits of the present approach include treatment for small and thin plates, elimination of the need to introduce a precrack, and avoidance of dealing with local material nonlinearity effects for the KC measurements. Finally, the bilayer configuration resembles occlusal loading of a ceramic restoration (brittle layer) bonded to a posterior tooth (compliant substrate).

Clinical utility of Pandy test in the face of quantitative CSF total protein and albumin: A retrospective study and literature review

INTRODUCTION

Qualitative Pandy test has long been used to indicate raised globulins in the cerebrospinal fluid (CSF). Despite its shortfalls and the availability of quantitative CSF protein assays, Pandy test continues to be performed in clinical laboratories across Malaysia.

OBJECTIVES

(1) Compare diagnostic performance of Pandy test to CSF total protein and albumin; (2) Conduct literature review on clinical utility of Pandy test.

MATERIALS AND METHODS

This is a retrospective, cross-sectional study involving 890 inpatients of all ages with CSF biochemistry analysed in Hospital Pulau Pinang over a period of 7 months. Patient demographics, clinical diagnosis and CSF total protein, albumin and Pandy results were collected and analysed using Mann-Whitney U test, Spearman rank-order correlation coefficient, Chi Square test and receiver operating characteristic (ROC) curve analysis.

RESULTS

CSF total protein, CSF albumin, CSF protein-albumin difference and age showed significantly higher median values in patients with positive Pandy compared to negative Pandy. Significant associations were found between positive Pandy test with clinical diagnosis (Cramers V 0.443, p<0.01), sample haemolysis (Phi 0.326, p<0.01), CSF protein-albumin difference (Spearman 0.727, p<0.001), CSF total protein (Spearman 0.710, p<0.001) and CSF albumin (Spearman 0.662, p<0.01). All three quantified CSF parameters showed comparably good sensitivity and specificity in determining positive Pandy.

DISCUSSION AND CONCLUSION

Good correlation with CSF proteins, analytical issues and reagent hazards indicate no added clinical value of Pandy test in the face of quantified CSF total protein and albumin. Abolishing the test saves resources, reduces occupational hazards and shortens turnaround time without compromising diagnosis.

O52 Plasma circulating cell-free messenger RNA as a potential biomarker of melanoma

Introduction

Blood-borne cell-free nucleic acids are increasingly emerging as significant non-invasive adjuncts to current methods of disease status evaluation in cancer patients. In this study, we sought to examine whether significant differences exist in the plasma transcriptomic profile of advanced melanoma patients with a high disease burden compared to patients with therapeutic response.

Method

Plasma circulating cell-free messenger ribonucleic acid (ccfmRNA) was extracted from twenty patients with stage IV melanoma receiving immunotherapy. Pathway focused gene expression analysis was performed. Patients were assessed with paired blood sample collection and CT scan assessments at baseline and at 3 months follow up. Response Evaluation Criteria in Solid Tumours (RECIST 1.1) was used for tumour burden estimation.

Result

In stage IV melanoma patients, CCL5, GZMB and MYD88 genes were significantly over-expressed (P &lt; 0.05 versus healthy controls). In patients with high disease burden or progressive disease, CCL18, CCR1, CCR4, CD274, CSF2, and GBP1 genes were significantly over-expressed (P &lt; 0.05 versus patients with therapeutic response). Finally, in stage IV melanoma patients with brain metastases, CCL18, CCR1, CCR4, CD274, CSF2, EGF, GBP1, and PTGS2 genes were significantly over-expressed (P &lt; 0.05, versus patients without brain metastasis).

Conclusion

Significant differences were observed in the plasma transcriptomic profile between the various melanoma patient groups, and we postulate that these differences may be exploited to identify novel therapeutic targets or biomarkers relevant to melanoma. CCL4 and CCL5 are prognostic in melanoma, both genes had significantly higher expressions in low disease burden patients compared to patients with a high disease burden.

Take-home Message

CCL4 and CCL5 ccfmRNA transcripts are prognostic in melanoma. High expression of both genes is favourable in melanoma patients.

O51 The utility of plasma circulating cell-free messenger RNA as a biomarker of glioma: a pilot study

Introduction

Research into the potential utility of plasma-derived circulating cell-free nucleic acids as non-invasive adjuncts to radiological imaging has been occasioned by the invasive nature of brain tumour biopsy. Circulating-cell-free messenger RNAs are short fragments of RNA present in blood. The objective of this study was to determine whether significant differences exist in the plasma transcriptomic profile of glioma patients relative to differences in their tumour characteristics, and also whether any observed differences were representative of synchronously obtained glioma samples and TCGA glioma derived RNA.

Method

Blood samples were collected from twenty-nine patients prior to tumour resection. Plasma ccfmRNA and glioma derived RNA were extracted and profiled.

Result

BCL2L1, CXCL5, GZMB, HLA-A, HLA-C, IRF1, MYD88, TGFB1, TLR2, and TP53 genes were significantly over-expressed in glioma (high-grade-glioma-HGG and low-grade-glioma-LGG) patients (P &lt; 0.05, versus control). BCL2L1, GZMB and HLA-A genes were significantly over-expressed in HGG patients (P &lt; 0.05, versus LGG patients). There was positive correlation between the magnitude of fold change of differentially expressed genes in plasma and glioma derived RNA (Spearman r = 0.6344, n = 14, P = 0.017), and with the mean FPKM of TCGA glioma derived RNA samples (Spearman r = 0.4614, n = 19, P = 0.047). There was positive correlation between glioma radiographic tumour burden and the magnitude of fold change of CSF3 gene (r = 0.9813, n = 20, P &lt; 0.001).

Conclusion

We identified significant differential expression of genes involved in cancer inflammation and immunity among patients with different glioma grades, and we identified positive correlation between the plasma transcriptomic profile and tumour samples, and with TCGA glioma derived RNA.

Take-home Message

The plasma transcriptomic profile of glioma patients appears to be representative of synchronously obtained glioma samples.

O9: DETECTION OF RELEVANT GENE MUTATIONS IN GLIOMA USING PLASMA CELL FREE DNA

Background

Comprehensive molecular profiling of gliomas provide information essential for accurate biological classification beyond traditional histopathology. Genomic profiling utilizing tumour tissue samples inevitably involves obtaining tissues through potentially hazardous surgical procedures or stereotactic biopsies carrying risks of morbidity and mortality. Tissues from biopsies may also be insufficient or fail to capture a comprehensive picture of the tumours genetic profile due to tumour heterogeneity. In these contexts, complementary minimally invasive strategies are needed for molecular profiling of gliomas. Cell free DNA (cfDNA) has emerged as an easily accessible biomarker containing fragments of circulating tumour DNA (ctDNA) released into plasma through apoptosis. We explored its potential utility in genomic profiling of brain tumours.

Method

Plasma cfDNA from patients with radiographically suspected brain malignancies were extracted and quantified before planned surgical interventions. Cell free DNA was extracted using a QIAamp Circulating Nucleic Acid Kit (Qiagen), and was quantified (ng cfDNA/mL) using a DS-11 FX Spectrophotometer (DeNovix). Pathway focused profiling of somatic mutation status was performed using QBiomarker Somatic Mutation PCR Arrays for human brain cancers (Qiagen) through real time PCR (Roche).

Result

Somatic mutations in human brain cancer were evaluated in the following genes; BRAF, CTNNB1/beta-catenin, EGFR, IDH1, IDH2, KRAS, NF2, NRAS, PIK3CA, and PTEN. A total of 14 (70%) patients had greater than 1 somatic mutation detected in their plasma cfDNA.

Conclusion

We postulate that glioma derived circulating tumour DNA occur in plasma, and genomic analysis using cell free DNA may complement current methods of glioma genomic characterisation.

Take-home message

Glioma derived circulating tumour DNA occur in plasma.

Prognostic significance of bone marrow 2-[18F]-fluoro-2-deoxy-d-glucose uptake in diffuse large B-cell lymphoma: relation to iliac crest biopsy results

AIM

To investigate the prognostic significance of bone marrow (BM) 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) uptake in relation to posterior iliac crest BM biopsy (BMB) results in diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS

Pretreatment integrated positron-emission tomography(PET)/computed tomography (CT) images of 512 DLBCL patients who underwent BMB and received rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy were analysed retrospectively. BM uptake was assessed visually and by maximum standard uptake value (SUVmax). Associations with lymphoma-specific survival (LSS) were assessed using Kaplan-Meier and Cox regression analyses.

RESULTS

FDG(+) BM was observed in 64 cases (41 focal, 12 heterogeneous, 11 diffuse). This finding distinguished iliac crest involvement (positive in 59 and negative in 453) with 89.6% accuracy (459/512) and 93.6% specificity (424/453). In BMB(+) patients, BM-to-liver SUVmax ratio >1.8 concurred perfectly with FDG(+) BM. During 52 months of follow-up, there were 156 lymphoma-related deaths. In the entire population, multivariate analysis revealed high International Prognostic Index (IPI; p<0.001), old age (p=0.003), bulky disease (p=0.011), BMB(+) (p=0.028), and FDG(+) BM (p=0.019) as independent predictors of worse LSS. In the BMB(+) subgroup, high National Comprehensive Cancer Network-revised IPI (NCCN-IPI; p=0.029) and FDG(+) BM (p=0.008) were significant independent predictors. Among BMB(+) patients with low to low-intermediate NCCN-IPI, FDG(+) BM was associated with significantly worse 2-year LSS (33.3% versus 100%; p=0.017). The same was true among those with high-intermediate NCCN-IPI (34.7% versus 76.9%.; p=0.026).

CONCLUSION

Increased BM FDG in DLBCL is a predictor of worse LSS independent of BMB results and other prognostic variables including IPI/NCCN-IPI.

Cell-Free DNA Promotes Thrombin Autolysis and Generation of Thrombin-Derived C-Terminal Fragments

Cell-free DNA (cfDNA) is the major structural component of neutrophil extracellular traps (NETs), an innate immune response to infection. Antimicrobial proteins and peptides bound to cfDNA play a critical role in the bactericidal property of NETs. Recent studies have shown that NETs have procoagulant activity, wherein cfDNA triggers thrombin generation through activation of the intrinsic pathway of coagulation. We have recently shown that thrombin binds to NETs in vitro and consequently can alter the proteome of NETs. However, the effect of NETs on thrombin is still unknown. In this study, we report that DNA binding leads to thrombin autolysis and generation of multiple thrombin-derived C-terminal peptides (TCPs) in vitro. Employing a 25-residue prototypic TCP, GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE), we show that TCPs bind NETs, thus conferring mutual protection against nuclease and protease degradation. Together, our results demonstrate the complex interplay between coagulation, NET formation, and thrombin cleavage and identify a previously undisclosed mechanism for formation of TCPs.

Angiosarcoma - a rare fatal cause of recurrent pericardial effusions

A 40-year-old man presented to the Hospital Sultanah Bahiyah, Alor Setar, Kedah, with constitutional and respiratory symptoms. Physical examination and echocardiogram demonstrated massive pericardial effusion. Patient required multiple attempts of pericardiocentesis due to recurrent pericardial effusion. Initial workup including pericardial fluids examination and computed tomography imaging did not reveal any apparent cause. Magnetic resonance imaging showed a suspicious mass infiltrating into the right atrium. Autoimmune screening was negative. Patient was subsequently treated as having tuberculous pericarditis. However, his disease progressed rapidly and he eventually passed away due to right atrial rupture. Postmortem revealed a ruptured right atrial tumour leading to massive haemothorax. Histopathological examination confirmed the diagnosis of primary pericardial angiosarcoma.

Thrombin and Plasmin Alter the Proteome of Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs) consist of a decondensed DNA scaffold decorated with neutrophil-derived proteins. The proteome of NETs, or "NETome," has been largely elucidated in vitro. However, components such as plasma and extracellular matrix proteins may affect the NETome under physiological conditions. Here, using a reductionistic approach, we explored the effects of two proteases active during injury and wounding, human thrombin and plasmin, on the NETome. Using high-resolution mass spectrometry, we identified a total of 164 proteins, including those previously not described in NETs. The serine proteases, particularly thrombin, were also found to interact with DNA and bound to NETs in vitro. Among the most abundant proteins were those identified previously, including histones, neutrophil elastase, and antimicrobial proteins. We observed reduced histone (H2B, H3, and H4) and neutrophil elastase levels upon the addition of the two proteases. Analyses of NET-derived tryptic peptides identified subtle changes upon protease treatments. Our results provide evidence that exogenous proteases, present during wounding and inflammation, influence the NETome. Taken together, regulation of NETs and their proteins under different physiological conditions may affect their roles in infection, inflammation, and the host response.

Upper gastrointestinal haemorrhage in severe dengue: To scope or not to scope?

Upper gastrointestinal haemorrhage (UGIH) in severe dengue represents a clinical dilemma in term of management. The recommended treatment in dengue with UGIH involves blood product transfusion support and proton pump inhibitor (PPI) infusion. Despite being the mainstay of treatment in non-dengue UGIH, the role of endoscopic haemostatic intervention in severe dengue remains controversial. In the present report, we present a case of severe dengue complicated with upper gastrointestinal haemorrhage successfully underwent early therapeutic endoscopic intervention in a district hospital.

Thoracic Epidural Clonidine Attenuates Haemodynamic Responses Induced by Endobronchial Intubation

Laryngoscopy and endobronchial intubation usually cause transient hypertension and tachycardia. We investigated whether thoracic epidurally injected 3 μg/kg clonidine attenuates cardiovascular responses to intubation compared with 2 μg/kg fentanyl and 1 mg/kg lidocaine. Epidural catheterization was performed at the T6–T7 or T7–T8 intervertebral space, and saline or clonidine in saline was injected 20 min before anaesthetic induction. Anaesthesia was induced using 5 mg/kg thiopental sodium and 0.1 mg/kg vecuronium. Laryngoscopy and endobronchial intubation were performed 2 min later. Mean blood pressure and heart rate were measured throughout anaesthetic induction. In the control group and the fentanyl group, mean blood pressure and heart rate 3 min after endobronchial intubation were elevated significantly compared with baseline. In the clonidine group, however, mean blood pressure and heart rate did not increase compared with baseline. The control group had higher mean blood pressure and heart rate than the clonidine group 3 min after endobronchial intubation. Thoracic epidural clonidine may attenuate the haemodynamic response to endobronchial intubation.

Neutrophils Self-Regulate Immune Complex-Mediated Cutaneous Inflammation through CXCL2

Deposition of immune complexes (ICs) in tissues triggers acute inflammatory pathology characterized by massive neutrophil influx leading to edema and hemorrhage, and is especially associated with vasculitis of the skin, but the mechanisms that regulate this type III hypersensitivity process remain poorly understood. Here, using a combination of multiphoton intravital microscopy and genomic approaches, we re-examined the cutaneous reverse passive Arthus reaction and observed that IC-activated neutrophils underwent transmigration, triggered further IC formation, and transported these ICs into the interstitium, whereas neutrophil depletion drastically reduced IC formation and ameliorated vascular leakage in vivo. Thereafter, we show that these neutrophils expressed high levels of CXCL2, which further amplified neutrophil recruitment and activation in an autocrine and/or paracrine manner. Notably, CXCL1 expression was restricted to tissue-resident cell types, but IC-activated neutrophils may also indirectly, via soluble factors, modulate macrophage CXCL1 expression. Consistent with their distinct cellular origins and localization, only neutralization of CXCL2 but not CXCL1 in the interstitium effectively reduced neutrophil recruitment. In summary, our study establishes that neutrophils are able to self-regulate their own recruitment and responses during IC-mediated inflammation through a CXCL2-driven feed forward loop.

Factors influencing late stage of breast cancer at presentation in a district Hospital - Segamat Hospital, Johor

INTRODUCTION

In Malaysia, late stage presentation of breast cancer (stage III or IV) has been a healthcare problem that varies geographically throughout the country. This study aims to understand the factors influencing late stage of breast cancer at presentation among Malaysian women in Segamat Hospital, Johor, which is a district hospital.

METHODS

A retrospective descriptive study was conducted on secondary data of all newly diagnosed breast cancer women from 1st August 2011 to 28th February 2014. Secondary data includes age, ethnicity, marital status, family history, education level, occupation, presenting symptom, duration of symptom, tumour size, tumour pathology, tumour grading, oestrogen, progesterone and HER-2 receptor status were collected and analysed using SPSS version 20.0.0.

RESULT

In total, data from 52 women was analysed and two women were excluded for incompleteness as these women defaulted. Late stage at presentation was 59.6% of all new cases (17.3% stage III and 42.3% stage IV). The commonest age group of all women diagnosed with breast cancer was in the 5th decade. Majority of them were Malay, married and housewives with no family history of breast cancer. The statistically significant factors associated with late stage at presentation include Malay ethnicity (p=0.019), presenting symptoms other than breast lump (p=0.047), and duration of breast lump more than 3 months (p=0.009).

DISCUSSION/CONCLUSION

The study demonstrated presentation at late stage of breast cancer is a major health concern among Malaysian women in district hospital. This may be attributed to different sociocultural beliefs, strong belief in complementary and alternative medicine, lack of awareness, and difficult accessibility to healthcare services.

Correlation of idiopathic scoliosis assessments between newly developed Milwaukee Topographic Scanner and Quantec

The Milwaukee Topographic Scanner (MTS) is a newly developed system, which utilizes laser technology to obtain three-dimensional topographic evaluation of the spine. The goal of this study was to determine the correlation of topographic measurements between MTS and Quantec Spinal Imaging System. Twelve parameters generated by the MTS and Quantec Spinal Imaging System was compared to each other using the Pearson Coefficient. Twenty patients between the ages 16-18 with scoliosis were evaluated with the MTS and Quantec. There were several parameters, which showed high correlations especially back height (0.972), coronal curve (0.952), and left trunk volume (0.905). MTS is a reliable three-dimensional topographic alternative to radiographs without the exposure to radiation.

Paradoxical emboli from left superior vena cava causing recurrent brain abscess

Persistent left superior vena cava is a rare but well-recognised condition. We describe a case of persistent left superior vena cava draining directly into the left atrium, with a fixed anatomical right-to-left shunt and paradoxical embolic events causing recurrent brain abscess. Surgical ligation was curative.

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.

The role of small intestinal bacterial overgrowth in postgastrectomy patients

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is expected in postgastrectomy patients; however, its role has not been clarified. This study was to estimate the prevalence of SIBO and investigate the clinical role of SIBO in postgastrectomy patients.

METHODS

This prospective study involved 76 patients who underwent gastrectomy for early gastric cancer with no evidence of recurrence. An H(2)-CH(4) breath test with oral glucose challenge test was performed to diagnose SIBO and dumping syndrome. Sigstad dumping questionnaires, serum glucose, hematocrit and pulse rate were simultaneously monitored for every 30 min for 3 hours.

KEY RESULTS

There were significant differences in SIBO between the postgastrectomy patients and controls (77.6%vs 6.7%, P < 0.01). Abdominal fullness or borborygmus during oral glucose load were more common in SIBO-positive than in negative patients (50.8%vs 17.6%, P = 0.03), and were the independent factors for predicting SIBO in postgastrectomy patients (P = 0.02). The prevalences of dumping syndrome and hypoglycemia after oral glucose were 35 (46.1%) and 19 (25.0%), and were not different between both groups. However, the plasma glucose was significantly lower in SIBO-positive than in SIBO-negative patients at 120 and 150 min after oral glucose load (P < 0.05). No significant differences were observed in pulse rate and hematocrit in both groups.

CONCLUSIONS & INFERENCES

SIBO is common among postgastrectomy patients. It appears to be associated with postprandial intestinal symptoms and might aggravate late hypoglycemia. SIBO could be a new therapeutic target for managing intestinal symptoms in postgastrectomy patients.

The role of small intestinal bacterial overgrowth in postgastrectomy patients

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is expected in postgastrectomy patients; however, its role has not been clarified. This study was to estimate the prevalence of SIBO and investigate the clinical role of SIBO in postgastrectomy patients.

METHODS

This prospective study involved 76 patients who underwent gastrectomy for early gastric cancer with no evidence of recurrence. An H(2)-CH(4) breath test with oral glucose challenge test was performed to diagnose SIBO and dumping syndrome. Sigstad dumping questionnaires, serum glucose, hematocrit and pulse rate were simultaneously monitored for every 30 min for 3 hours.

KEY RESULTS

There were significant differences in SIBO between the postgastrectomy patients and controls (77.6%vs 6.7%, P < 0.01). Abdominal fullness or borborygmus during oral glucose load were more common in SIBO-positive than in negative patients (50.8%vs 17.6%, P = 0.03), and were the independent factors for predicting SIBO in postgastrectomy patients (P = 0.02). The prevalences of dumping syndrome and hypoglycemia after oral glucose were 35 (46.1%) and 19 (25.0%), and were not different between both groups. However, the plasma glucose was significantly lower in SIBO-positive than in SIBO-negative patients at 120 and 150 min after oral glucose load (P < 0.05). No significant differences were observed in pulse rate and hematocrit in both groups.

CONCLUSIONS & INFERENCES

SIBO is common among postgastrectomy patients. It appears to be associated with postprandial intestinal symptoms and might aggravate late hypoglycemia. SIBO could be a new therapeutic target for managing intestinal symptoms in postgastrectomy patients.

The analgesic effect of remifentanil on prevention of withdrawal response associated with the injection of rocuronium in children: no evidence for a peripheral action

Remifentanil pre-treatment has been reported to decrease the incidence of rocuronium injection-associated withdrawal movement. This study was designed to explore the site of action of remifentanil for reducing withdrawal response during rocuronium injection in children. Ninety-six paediatric patients were randomly assigned to three groups. After induction of anaesthesia with 5 mg/kg 2.5% thiopental sodium, 2 ml saline (placebo group) or 0.5 microg/kg remifentanil (group R), was injected intravenously 1 min before 0.6 mg/kg rocuronium. In a third group (group R'), the venous retention of 0.5 microg/kg remifentanil was maintained for 30 s followed by tourniquet release and injection of 0.6 mg/kg rocuronium. Withdrawal response was graded using a four-point scale. The incidence of withdrawal movement after rocuronium administration was 94%, 22% and 81% in the placebo, R, and R' groups, respectively. This study demonstrated that the pre-treatment effect of remifentanil for reducing rocuronium-associated withdrawal response occurs mainly through a central action.

Combined heart-liver transplantation with extended cardiopulmonary bypass

We report a case of combined heart and liver transplantation for familial amyloid polyneuropathy. This is the first such combined transplant performed in Asia, and differs from previously described cases, in that cardiopulmonary bypass was continued at partial flow during liver transplantation in our case. This was done in order to provide haemodynamic support to the cardiac graft and to protect it from the impending reperfusion insult that frequently accompanies liver transplantation. The utility of this management course is discussed, along with its actual and potential complications. We also describe the impact of a lung-protective ventilation strategy employed during cardiac transplantation.

Programmed death (PD)-1 molecule and its ligand PD-L1 distribution among memory CD4 and CD8 T cell subsets in human immunodeficiency virus-1-infected individuals

Human immunodeficiency virus (HIV)-1 causes T cell anergy and affects T cell maturation. Various mechanisms are responsible for impaired anti-HIV-1-specific responses: programmed death (PD)-1 molecule and its ligand PD-L1 are negative regulators of T cell activity and their expression is increased during HIV-1 infection. This study examines correlations between T cell maturation, expression of PD-1 and PD-L1, and the effects of their blockade. Peripheral blood mononuclear cells (PBMC) from 24 HIV-1(+) and 17 uninfected individuals were phenotyped for PD-1 and PD-L1 expression on CD4(+) and CD8(+) T cell subsets. The effect of PD-1 and PD-L1 blockade on proliferation and interferon (IFN)-gamma production was tested on eight HIV-1(+) patients. Naive (CCR7(+)CD45RA(+)) CD8(+) T cells were reduced in HIV-1 aviraemic (P = 0.0065) and viraemic patients (P = 0.0130); CD8 T effector memory subsets [CCR7(-)CD45RA(-)(T(EM))] were increased in HIV-1(+) aviraemic (P = 0.0122) and viraemic (P = 0.0023) individuals versus controls. PD-1 expression was increased in CD4 naive (P = 0.0496), central memory [CCR7(+)CD45RA(-) (T(CM)); P = 0.0116], T(EM) (P = 0.0037) and CD8 naive T cells (P = 0.0133) of aviraemic HIV-1(+) versus controls. PD-L1 was increased in CD4 T(EMRA) (CCR7(-)CD45RA(+), P = 0.0119), CD8 T(EM) (P = 0.0494) and CD8 T(EMRA) (P = 0.0282) of aviraemic HIV-1(+)versus controls. PD-1 blockade increased HIV-1-specific proliferative responses in one of eight patients, whereas PD-L1 blockade restored responses in four of eight patients, but did not increase IFN-gamma-production. Alteration of T cell subsets, accompanied by increased PD-1 and PD-L1 expression in HIV-1 infection contributes to anergy and impaired anti-HIV-1-specific responses which are not rescued when PD-1 is blocked, in contrast to when PD-L1 is blocked, due possibly to an ability to bind to receptors other than PD-1.

Shewanella fodinae sp. nov., isolated from a coal mine and from a marine lagoon

Strains JC15(T) and JC19 were isolated from samples collected from different locations in India, including a coal mine and a marine lagoon. Both strains were Gram-stain-negative rods, motile by means of a single polar flagellum, catalase- and oxidase-positive, and hydrolysed casein, produced H(2)S and showed beta-haemolysis. Strain JC15(T) grew optimally at pH 6 (range pH 5-8) while strain JC19 grew optimally at pH 7 (range pH 6-9) and both had a growth temperature optimum of 30-37 degrees C (range 22-40 degrees C). Both strains could grow chemo-organoheterotrophically and chemolithoautotrophically. Neither strain required NaCl for growth and both could tolerate up to 9 % (w/v) NaCl, with optimum growth at 5 % NaCl. Vitamin B(12) was required as a growth factor by both strains. The major fatty acids were iso-C(15 : 0), C(17 : 1)omega8c and iso-C(13 : 0) 3-OH. The DNA G+C contents of strains JC15(T) and JC19 were 53.6 and 54.3 mol%, respectively. A phylogenetic tree based on 16S rRNA gene sequence analysis showed that strains JC15(T) and JC19 were most closely related to Shewanella haliotis DW01(T) (approximately 94 % sequence similarity) and to other members of the genus Shewanella. Genomic relatedness (DNA-DNA hybridization) between strains JC15(T) and JC19 is 88 %. On the basis of phenotypic and molecular genetic evidence, strain JC15(T) represents a novel species of the genus Shewanella, for which the name Shewanella fodinae sp. nov. is proposed. The type strain is JC15(T) (=CCUG 57102(T) =NBRC 105216(T) =KCTC 22506(T)).

Resection of a giant malignant mediastinal peripheral nerve sheath tumour under cardiopulmonary bypass

Malignant peripheral nerve sheath tumour (MPNST) is a rare occurrence in the mediastinum. It is biologically aggressive and is generally resistant to chemoradiation therapy. The mainstay of treatment is complete surgical resection. We report a large MPNST which invaded into the adjacent aortic wall in a 50-year-old man. Extensive resection, which included aortic reconstruction under cardiopulmonary bypass and deep hypothermic arrest, was necessary for a good long-term outcome.

Clinics in diagnostic imaging (126). Right atrial myxoma

A 47-year-old woman presented with dyspnoea on exertion for several weeks. Echocardiogram and multidetector computed tomography of the heart showed a right atrial mass typical of an atrial myxoma. This was confirmed on histology. The imaging features of atrial myxoma and other conditions presenting as a right-sided cardiac mass are discussed.

Antiviral activity of raoulic acid from Raoulia australis against Picornaviruses

RNA viruses are a major source of respiratory diseases worldwide. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Raoulic acid is a principal ingredient of the plant Raoulia australis Hook. F. Antiviral assay using cytopathic effect (CPE) reduction method showed that raoulic acid possessed strong antiviral activity against human rhinovirus 2 (HRV2) with a 50% inhibition concentration (IC(50)) value of less than 0.1mug/ml, human rhinovirus 3 (HRV3) with a IC(50) value of 0.19 microg/ml, coxsackie B3 (CB3) virus with IC(50) values of 0.33 microg/ml, coxsackie B4 (CB4) virus with IC(50) values of 0.40 microg/ml, and enterovirus 71 (EV71) virus with IC(50) values of less than 0.1 microg/ml. However, the compound did not possess antiviral activity against influenza A (Flu A/PR, Flu A/WS, H1N1) and B viruses at four concentrations ranging from 0.1 to 100 microg/ml.

Anaesthetists' nightmare: masseter spasm after induction in an undiagnosed case of myotonia congenita

We report an undiagnosed case of myotonia congenita in a 24-year-old previously healthy primigravida, who developed life threatening masseter spasm following a standard dose of intravenous suxamethonium for induction of anaesthesia. Neither the patient nor the anaesthetist was aware of the diagnosis before this potentially lethal complication occurred.

Evaluation of Subchronic Inhalation Toxicity of Dimethyl Disulfide in Rats

This study was carried out to investigate the potential subchronic inhalation toxicity of dimethyl disulfide (DMDS) via whole-body exposure in F344 rats. Groups of 10 rats of each sex were exposed to DMDS vapor by whole-body exposure at concentrations of 0, 5, 25, or 125 ppm for 6 h/day, 5 days/wk for 13 wk. All the rats were sacrificed at the end of treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. At 25 ppm, a decrease in the body weight gain, food intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and blood urea nitrogen (BUN) was observed in the males, but not in the females. However, at 125 ppm, a decrease in the body weight gain, food intake, and thymus weight and an increase in the weights of adrenal glands were observed in both genders. Serum biochemical investigations revealed a decrease in the AST, ALT, BUN, creatine phosphokinase (CPK), and triglyceride levels and an increase in the glucose level. In contrast, no treatment-related effects were observed in the 5 ppm group. The toxic potency of DMDS was slightly higher in males than that in females. In these experimental conditions, the target organ was not determined in rats. The no-observed-adverse-effect concentration (NOAEC) was found to be 5 ppm, 6 h/day for male rats and 25 ppm, 6 h/day for female rats.

Low-grade dysplasia in Barrett's esophagus has a high risk of progression

BACKGROUND AND STUDY AIMS

Surveillance in Barrett's esophagus relies on the detection of dysplasia by histopathology. However, the natural history of this condition, particularly that of low-grade dysplasia (LGD) is poorly understood. This paper describes our experience of LGD over a period of 21 years.

PATIENTS AND METHODS

Between 1984 and January 1995, 357 patients with Barrett's esophagus without dysplasia were recruited for annual surveillance: 34 of these patients developed LGD during this period. This was a retrospective cohort study of this group in terms of survival and cancer outcomes >/= 8 years after the original diagnosis of LGD, comparing them with the patients who did not develop LGD over the same period, with a histopathological review of the original diagnoses of LGD. The outcomes of 356/357 (99.7 %) of the patients were established in December 2004.

RESULTS

After 8 years, high-grade dysplasia (HGD) or cancer had developed in 9/34 patients with LGD (27 %) and in 16/322 controls (5 %). Cox's proportional hazards model revealed that the time from the first diagnosis of Barrett's esophagus to the first "event" of either HGD, esophageal cancer, or death did not show a statistically significant difference between the two groups. A further analysis treating death as "loss to follow-up" showed a significantly increased risk for the LGD group to progress to HGD or cancer (hazard ratio 5.9 [95 % confidence interval 2.6 - 13.4], P< 0.001). The histopathology review demonstrated a fair level of agreement between pathologists, with a kappa value of 0.48.

CONCLUSIONS

Patients diagnosed with LGD during surveillance of Barrett's esophagus are at a considerably increased risk of progressing to develop esophageal cancer over an 8-year period but most deaths are not cancer-related.

Bilateral pneumothoraces as a complication of acupuncture

Pneumothorax developing secondary to acupuncture is rare. However, in an undiagnosed case, it may cause fatality. The real incidence of acupuncture-related pneumothorax is not known but is acknowledged to be underdiagnosed and under-reported. We describe pneumothorax occurring in a 52-year-old woman who developed bilateral pneumothoraces, with one side being a tension pneumothorax, immediately following acupuncture. The needle was inserted at a paravertebral point at the level of the third vertebral spinous process.

Retinocollicular synaptogenesis and synaptic transmission during formation of the visual map in the superior colliculus of the wallaby (Macropus eugenii)

Spontaneous retinal activity has been implicated in the development of the topographic map in the superior colliculus (SC) but a direct demonstration that it reaches the colliculus is lacking. Here we investigate when the retinocollicular projection is capable of transmitting information from the retina in a marsupial mammal, the wallaby (Macropus eugenii). The projection develops postnatally, allowing in vivo analysis throughout development. Quantification of retinocollicular synaptogenesis has been combined with electrophysiology of the development and characteristics of retinocollicular transmission, including in vivo and in vitro recording in the same animals. Prior to postnatal day (P) 12-14 in vitro recording detected only presynaptic activity in retinal axons in the colliculus, in response to stimulation of the optic nerve. Postsynaptic responses, comprising both N-methyl-d-aspartate (NMDA) and non-NMDA responses, were first detected in vitro at P12-14 and retinal synapses were identified. In contrast, postsynaptic responses to optic nerve stimulation could not be detected in vivo until P39, around the time that retinal axons begin arborizing. Around this age density and numbers of total synapses began increasing in the retinorecipient layers of the colliculus. By P55-64, the numbers of retinal synapses had increased significantly and density and numbers of retinal and total synapses continued to increase up to P94-99. During this time the map is undergoing refinement and degenerating axons and synapses were present. The discrepancy between in vitro and in vivo onset of functional connections raises the question of when retinal activity reaches collicular cells in the intact, unanaesthetized animal and this will require investigation.

The outcome of suspected upper gastrointestinal bleeding with 24-hour access to upper gastrointestinal endoscopy: a prospective cohort study

BACKGROUND AND STUDY AIM

The aim was to evaluate the 30-day mortality after endoscopy for suspected upper gastrointestinal bleed, following the implementation of national audit guidelines at our hospital.

PATIENTS AND METHODS

All patients with suspected upper gastrointestinal bleeding, referred for endoscopy to our teaching hospital between October 2001 and December 2003, were included in a prospective cohort study.

RESULTS

A total of 716 patients with suspected upper gastrointestinal tract haemorrhage were referred for urgent endoscopy. The median age was 69 years (interquartile range 51 - 80 years). Bleeding from peptic ulcer remained the single most common endoscopic diagnosis (40 %). The overall re-bleeding rate for all patients with a gastrointestinal haemorrhage was 10 %. The overall 30-day mortality rate was 14.6 %. This was not significantly different from the mortality rate in 1995 of 10.5 % ( P = 0.11). Patients who died were significantly older (78 vs. 67 years, 95 %CI of the difference 5 to 12, P < 0.001). However, in only 29 % (30/105) was gastrointestinal haemorrhage stated in the death certificate as a factor which contributed to their death.

CONCLUSIONS

Our results show that implementing the good practice guideline has a limited impact on overall mortality because of contributing factors that are beyond the control of clinicians.

Regulation of the cell swelling-activated chloride conductance by cholesterol-rich membrane domains

AIM

The role of high cholesterol-containing microdomains in the signal transduction cascade leading to the activation of volume-regulated anion channels (VRACs) was studied.

METHODS

Osmotic cell swelling-induced efflux of 125I- was determined in human epithelial Intestine 407 cells and in skin fibroblasts obtained from healthy controls or Niemann-Pick type C (NPC) patients. Cellular cholesterol content was modulated by pre-incubation with 2-hydroxypropyl-beta-cyclodextrin in the presence of acceptor lipid vesicles.

RESULTS

Osmotic cell swelling of human Intestine 407 cells leads to the rapid activation of a compensatory anion conductance. Treatment of the cells with cyclodextrin enhanced the response to submaximal hypotonic stimulation by approx. twofold, but did not further increase the efflux elicited by a saturating stimulus. In contrast, the volume-sensitive anion efflux was markedly inhibited when cholesterol-loaded cyclodextrin was used. Potentiation of the response by cholesterol depletion was maintained in caveolin-1 deficient Caco-2 colonocytes as well as in sphingomyelinase-treated Intestine 407 cells, indicating that cholesterol-rich microdomains are not crucially involved. However, treatment of the cells with progesterone, an inhibitor of NPC1-dependent endosomal cholesterol trafficking, not only markedly reduced the hypotonicity-provoked anion efflux, but also prevented its potentiation by cyclodextrin. In addition, the volume-sensitive anion efflux from human NPC skin fibroblasts was significantly smaller when compared with control fibroblasts.

CONCLUSIONS

The results support a model of regulatory volume decrease involving recruitment of volume-sensitive anion channels from intracellular compartments to the plasma membrane.

Necrotizing fasciitis of the lower limb: an outcome study of surgical treatment

Necrotizing fasciitis is a limb- and life-threatening rapidly spreading infection affecting the deep fascia with secondary necrosis of the subcutaneous tissue. It requires immediate medical attention and emergency surgery to prevent morbidity and death. This study was undertaken to determine its co-morbidity and risk factors affecting the outcome of its surgical treatment. This is a retrospective review of 36 cases of necrotizing fasciitis of the lower limb treated in our center between 1998 and 2002. Only 19% of the cases were correctly diagnosed upon admission and 48.6% were initially diagnosed as 'cellulitis'. Diabetes mellitus was the most common co-morbid. Pseudomonas, Staphylococcus, Streptococcus and Enterobactericae were the common pathogens isolated. Ten patients (27.8%) had major amputation as part of radical debridement. The overall mortality rate was 36% with laboratory parameters: high serum urea and creatinine, and low haemoglobin levels were predictors for higher mortality. Poor white cell response which is common in diabetic patients and a delay in surgical debridement were. notable attributes to a higher mortality. Necrotizing fasciitis is a serious infection associated with significant morbidity and mortality. A poor white blood cell response, high serum urea and creatinine, and low haemoglobin level were the predictors for mortality. Early diagnosis and prompt treatment are of paramount importance in the treatment of this infection.

Prospective study of acute gastrointestinal bleeding attributable to anti-inflammatory drug ingestion in the Yorkshire region of the United Kingdom

OBJECTIVE

To assess the general use of all non-steroidal anti-inflammatory drugs (NSAID) and their relation to upper gastrointestinal bleeding in view of National Institute for Clinical Excellence guidelines published in July 2001 in the UK.

METHODS

Cross sectional study on all patients who were referred for endoscopy for suspected upper gastrointestinal bleeding in six hospitals in Yorkshire region of the UK.

RESULTS

One hundred and sixty three patients presented for endoscopy for suspected upper gastrointestinal bleeding, 43 patients were taking at least one ulcerogenic drug, and 120 were not. The mean age difference between these two groups was eight years (p<0.01). The absolute difference between the proportion of patients with peptic ulcer disease/erosion (PUD) in NSAID with/without aspirin group and no ulcerogenic drug group was 31% (p = 0.02). The difference between the proportion of PUD in cyclo-oxygenase 2 with/without aspirin group and no ulcerogenic drug group was 30% (p = 0.1). The overall 30 days mortality rate was 14.1%.

CONCLUSIONS

Elderly patients are being inappropriately prescribed conventional NSAIDs. NSAIDs with or without aspirin use are still associated with a significant risk of upper gastrointestinal bleeding in the era of cyclo-oxygenase 2 selective agents. Substitution with cyclo-oxygenase 2 selective NSAIDs is not without risk of upper gastrointestinal bleeding.

Oesophageal haematoma and associated Mallory-Weiss tear

Intramural oesophageal haematoma is a rare condition that may present as vomiting or haematemesis. Mallory-Weiss tear has been proposed as a possible aetiology but the evidence to support this is circumstantial. A case of oesophageal haematoma associated with evidence of Mallory-Weiss tear on endoscopy that helps to support this hypothesis is presented.

Bioequivalence of pravastatin tablet formulations assessed in Korean males

AIM

Determination of the bioequivalence of 2 pravastatin tablet formulations manufactured in Korea.

PATIENTS AND METHODS

Twenty-three healthy male Korean volunteers received each of the 2 pravastatin formulations at a dose of 20 mg in a 2 x 2 crossover study. There was a 1-week washout period between doses. Plasma concentrations of pravastatin were monitored using high-performance liquid chromatography over a period of 8 hours after administration. AUC(0-8h) (the area under the plasma concentration-time curve from time zero to the last measured time in plasma, 8 h) was calculated using the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC(0-8h) and Cmax and untransformed tmax.

RESULTS

The point estimates and 90% confidence intervals for AUC(0-8h) (parametric) and Cmax (parametric) were 1.067 (0.968 to approximately 1.176) and 1.074 (0.999 to approximately 1.155), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. The corresponding value of tmax was 0.000 (-0.250 to approximately 0.250).

CONCLUSION

These results indicate that the 2 medications of pravastatin are bioequivalent and, thus, may be prescribed interchangeably.

Ten year follow up of ulcerative colitis patients with and without low grade dysplasia

BACKGROUND AND AIMS

Low grade dysplasia (LGD) is believed to predispose to colorectal cancer (CRC), and proctocolectomy has been advocated when this is identified. Between 1978 and 1990, 160 patients with longstanding extensive ulcerative colitis (UC) were recruited for annual colonoscopic surveillance and 40 developed LGD at some stage. We report the outcome of this cohort 10 years after the original study ended.

METHODS

Retrospective cohort study and histopathological review of the original diagnoses of LGD. The outcome of 158/160 (98.8%) patients was established in 2000.

RESULTS

Of the 128 patients still alive and with an intact colon at the end of 1990, two were not traceable, 29 had LGD, and 97 had no dysplasia (controls). After 10 years, high grade dysplasia (HGD) or CRC developed in 3/29 LGD (10%) and in 4/97 controls (4.0%). Kaplan-Meier analysis from 1991 to death or colectomy did not show a statistically significant difference between the two groups (log rank test p=0.63). Histopathological review demonstrated the unreliability of LGD diagnosis. Agreement between pathologists was uniformly poor: kappa <0.4 for all comparisons.

CONCLUSION

LGD diagnosis is not sufficiently reliable to justify prophylactic colectomy. Conservative management of established LGD cases should not be ruled out.

Synthesis and binding affinities of 2 beta-(3-iodoallyloxycarbonyl)-3 beta-(4-substituted-aryl)tropane analogues as ligands for the dopamine transporter studies

Tropane analogues from cocaine, which is known to be one of the most reinforcing and addictive compounds, were designed, synthesized, and characterized for inhibition of presynaptic uptake of dopamine (DA) in brain. Eight new derivatives of 3 beta-aryl-2 beta-(3-iodoallyloxycarbonyl)tropanes were synthesized and tested for their potential abilities to displace [(3)H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN 35,428) binding to the rat striatal membranes.

Xenobiotic response in humanized double transgenic mice expressing tetracycline-controlled transactivator and human CYP1B1

The cytochrome P450 enzymes (P450s or CYPs) are a superfamily of hemeproteins that catalyze the monooxygenation of a wide range of endobiotic and xenobiotic substrates. A typical strategy in toxicological research and testing involves applying a toxicant at high doses for a short period to homogeneous animals under controlled conditions. However, the conditions of this approach have very little in common with actual human exposure. Transgenic (Tg) mice carrying human genes encoding a drug-metabolizing enzyme (CYP) offer a solution to many of the difficulties in the evaluation of chemical toxicity. It has been demonstrated that the expression of human CYP transgenes under the control of mammalian-inducible promoters exhibits relatively poor fold increases after induction. In this study, we used the tetracycline-regulated (tet) promoter system to increase the expression of the human CYP1B1 (hCYP1B1) gene in the tissues of transgenic mice. By mating two lineages of transgenic mice, double transgenic (dTg) mice expressing both tTA and hCYP1B1 genes under the control of the tet promoter were successfully produced, into which the two transgenes were introduced in an embryo. The expression pattern of tTA-driven hCYP1B1 transgene featured a fold induction of more than 3 to 12 in the brain, heart, and lung and 2- to 4-fold induction in the liver, kidney, and intestine upon doxycycline removal. Immunohistochemical staining with hCYP1B1 antibody was also increased by the removal of doxycycline. In addition, the activities of CYP liver microsomes in the dTg mice without doxycycline showed an increase compared to that in the dTg mice treated with doxycycline. The level of activities correspond to the levels of human CYP1B1 protein expression in the Tg mice (-dox) that was increased by 2-fold induction as compared to that of the dTg mice with doxycycline. Thus, overproduction in Tg can be purified and the activity of purified human CYP1B1 can be characterized by alterations to the coding sequence in order to solve the physiological function of this enzyme in a humanized in vivo system. It is also possible to examine the activity of purified human CYP1B1 using several environmental toxicants such as procarcinogens.

Occlusive myocardial infarction: investigation of bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging in a cat model

PURPOSE

To test whether bis-gadolinium mesoporphyrins-enhanced magnetic resonance (MR) imaging can accurately depict irreversibly damaged myocardium in occlusive myocardial infarction.

MATERIALS AND METHODS

Ten cats were subjected to 90 minutes of occlusion of the left anterior descending coronary artery. Bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging was performed in the cats for 6 hours. Histopathologic examinations with 2'3'5-triphenyl tetrazolium chloride (TTC) staining and electron microscopy were performed on the resected specimens. The time course and pattern of signal intensity enhancement were evaluated. The size of the infarcted myocardium was estimated on the MR images by measuring the size of the signal intensity-enhanced area.

RESULTS

In eight of 10 cats, it was impossible to distinguish infarcted myocardium from normal myocardium at visual inspection of T1-weighted MR images. The contrast ratio between infarcted and normal myocardium did not increase significantly over time. In one of the two remaining cats, a doughnut pattern of signal intensity enhancement was noted. The other cat showed intensely homogeneous enhancement of infarcted myocardium at MR imaging. The size of the area of signal intensity enhancement at MR imaging in these two cats was accurately mapped to that of the infarction on the TTC-stained specimens.

CONCLUSION

Occlusive myocardial infarction cannot be accurately detected at bis-gadolinium mesoporphyrins-enhanced MR imaging.

Irreversibly damaged myocardium at MR imaging with a necrotic tissue-specific contrast agent in a cat model

PURPOSE

To investigate the capability of a necrosis-avid magnetic resonance (MR) contrast agent, bis-gadolinium mesoporphyrins, for assessment of irreversibly damaged myocardium and to evaluate the time course of signal enhancement in the reperfused myocardium.

MATERIALS AND METHODS

Nine cats were subjected to 90 minutes of occlusion of the left anterior descending coronary artery followed by 90 minutes of reperfusion. Contrast material-enhanced T1-weighted spin-echo images were obtained for 12 hours in five cats and 6 hours in four cats. Pathologic examinations of the resected specimens were performed with 2'3'5-triphenyl tetrazolium chloride (TTC) histochemical staining and electron microscopy. The size of enhanced area on MR images was compared with that of irreversibly damaged myocardium with TTC staining. The time course of signal enhancement was evaluated.

RESULTS

The size of enhanced area on MR images was well correlated with that of irreversibly damaged myocardium with TTC staining. Maximum enhancement occurred 1-3 hours after administration of the contrast material, with mean enhancement of 171% that of normal myocardium. Electron microscopic examinations showed severe myocardial damage in the irreversibly damaged myocardium but only mild edematous changes in the reversibly damaged myocardium.

CONCLUSION

MR images enhanced with bis-gadolinium mesoporphyrins provide accurate sizing of irreversibly damaged myocardium with a strong and persistent signal enhancement in the reperfused myocardium.

Application of breath-hold T2-weighted, first-pass perfusion and gadolinium-enhanced T1-weighted MR imaging for assessment of myocardial viability in a pig model

The purpose of this study was to correlate the abnormal signal area on various magnetic resonance (MR) images to the infarct area on pathologic examination and to assess the myocardial viability on the basis of MR images. T2-weighted, first-pass perfusion, and delayed gadolinium-enhanced T1-weighted images were used as "one-stop examinations" in a pig model of reperfused myocardial infarction. The results of each MR image were compared with those of 2,3, 5-triphenyltetrazolium chloride (TTC) staining. The abnormal signal areas on T2-weighted and Gd-enhanced T1-weighted images were larger than the infarct areas on TTC staining (34.7% and 32.3% vs. 28.3%; P< 0.05), whereas the nonperfused areas on perfusion images were correlated (25.6% vs, 28.3%; P = 0.139). Electron microscopic examination showed severely distorted ultrastructures in the infarct areas and mildly damaged ultrastructures in the peri-infarct areas. Perfusion images probably reflected the infarct areas, whereas T2-weighted and Gd-enhanced T1-weighted images seemed to include peri-infarct as well as infarct areas.

Medical radiologic technologist review: effects on a population-based breast cancer screening program

PURPOSE

To evaluate the effects of medical radiologic technologist review of mammograms in a population-based breast cancer screening program.

MATERIALS AND METHODS

A technologist review pilot project was incorporated into the Regina, Saskatchewan, Canada, reading center. Technologists received special training in mammographic interpretation. They reviewed all 27,863 mammograms obtained at the center from July 1995 to September 1996 that were reviewed by a radiologist and selected cases for second blind reading by another radiologist. When the two radiologists' readings were in agreement, the report was sent. When the readings differed, a third opinion was obtained from the program's consulting radiologist. Changes in the number of mammograms interpreted as abnormal and the number of cancers detected were assessed.

RESULTS

The technologist review was responsible for the detection of nine cancers missed at the first radiologist's interpretation. Technologists were very discriminating; only 391 cases (1.4%) were sent for double reading. The positive predictive value of screening did not change significantly (7.5% without review, 8.1% with review; P > .20).

CONCLUSION

A substantial number of cancers were found with the technologist review. The number of mammograms interpreted as abnormal was reduced slightly. The technologist review proved to be a cost-effective alternative to double reading by two radiologists.