Brittle-Ductile Threshold in Lithium Disilicate under Sharp Sliding Contact.

Computer-aided design (CAD)/computer-aided manufacturing (CAM) milling and handpiece grinding are critical procedures in the fabrication and adjustment of ceramic dental restorations. However, due to the formation of microfractures, these procedures are detrimental to the strength of ceramics. This study analyzes the damage associated with current brittle-regime grinding and presents a potential remedy in the application of a safer yet still efficient grinding regime known as "ductile-regime grinding." Disc-shaped specimens of a lithium disilicate glass-ceramic material (IPS e.max CAD) were obtained by cutting and crystallizing the lithium metasilicate CAD/CAM blanks (the so-called blue blocks) following the manufacturer's instructions. The discs were then polished to a 1 µm diamond suspension finish. Single-particle micro-scratch tests (n = 10) with a conical diamond indenter were conducted to reproduce basic modes of deformation and fracture. Key parameters such as coefficient of friction and penetration depth were recorded as a function of scratch load. Further, biaxial flexure strength tests (n = 6) were performed after applying various scratch loads to analyze their effects on ceramic strength. Scanning electron microscopy (SEM) and focused ion beam (FIB) were used to characterize surface and subsurface damage. Statistical analysis was performed using one-way analysis of variance and Tukey tests. While the SEM surface analysis of scratch tracks revealed the occurrence of both ductile and brittle removal modes, it failed to accurately determine the threshold load for the brittle-ductile transition. The threshold load for brittle-ductile transition was determined to be 70 mN based on FIB subsurface damage analyses in conjunction with strength degradation studies. Below 70 mN, the specimens exhibited neither strength degradation nor the formation of subsurface cracks. Determination of the brittle-ductile thresholds is significant because it sets a foundation for future research on the feasibility of implementing ductile-regime milling/grinding protocols for fabricating damage-free ceramic dental restorations.

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).

Synchronous Primary Parosteal Osteosarcoma and Primary Mediastinal Germ Cell Tumour with Atypical Mycobacterial Infection - A Rare Phenomenon: A Case Report.

Mediastinal germ cell tumours are a rare group of extragonadal germ cell tumours with less than 5% prevalence of all germ cell tumours. Primary mediastinal germ cell tumours themselves account for 16-36% of the extragonadal germ cell tumours. Along the spectrum of osteosarcoma, parosteal osteosarcoma is a well-differentiated surface osteosarcoma with a prevalence of 4% of all osteosarcoma. As such synchronous primary parosteal osteosarcoma and primary mediastinal germ cell tumour are exceedingly rare. This leads to complexity in determining the most appropriate chemotherapy for two different types of tumours and its potential side effects of reduced immunity leading to potential secondary infection. Here we report a case of a 16-year-old boy who presented with synchronous primary osteosarcoma and primary mediastinal germ cell tumour, complicated with atypical mycobacterial infection post-operatively. Additionally, we discuss our choice of chemotherapy and the management of the atypical mycobacterial infection.

A Survey of Zone II Flexor Tendon Repair Techniques and Rehabilitation Protocols Preferred by Malaysian Orthopaedic Practitioners.

Introduction: Flexor tendon repair is challenging mainly due to the need to balance between a strong repair technique, ease of tendon gliding and early mobilisation to prevent adhesions while preventing tendon rupture. While different countries have different preferences in repair techniques, core sutures and suture types, there is still no study in Malaysia regarding our preference and whether we are following the current evidence. Materials and methods: We performed a survey with a standard questionnaire distributed during our annual national orthopaedic meeting in 2019. The standard questionnaire consisted of 24-objective multiple-choice questions concerning the treatment of flexor tendon injury were distributed with consent. A total of 290 questionnaires that were filled out correctly were included in this study. Results: The majority of respondents preferred the Modified Kessler technique (n=96, 33.1%) followed by the Adelaide technique (n=81, 27.9%) and Double Modified Kessler (n=45, 15.5%). However, for the number of core strands in the repair, the majority utilised the 4-strand (n=203, 70%), followed by 2-strand (n=34, 11.7%) and 6-strand (n=21, 7.2%). The majority utilised Prolene sutures (n=259, 89.3%) with a suture size of 4/0 (n=157, 54.1%). For rehabilitation, 56.9% (n=165) preferred early passive motion, 27.6% (n=80) early active motion and 14.8% (n=43) would strictly immobilise. Conclusion: There is still no consensus as to the best technique; however, the aim of tendon repairs is still the same around the world. It would be helpful to know our preferences to improve our current practice and outcomes following these common flexor tendon injuries in hand.

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.

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.

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.

Evaluation of a diagnostic 18F-FDG PET/CT strategy for differentiating benign from malignant retroperitoneal soft-tissue masses.

AIM: To investigate the optimal combined 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) diagnostic criteria for distinguishing between benign and malignant retroperitoneal soft-tissue masses (RPMs). MATERIALS AND METHODS: A total of 74 patients (M:F=34:40; age, 53±13.2 years) who underwent FDG PET/CT for the initial work-up of RPMs were included. The maximum standardised uptake value (SUVmax), tumour size, presence of fat or calcifications and separated hypermetabolic lesions were included as PET/CT diagnostic parameters. Receiver-operating characteristic (ROC) curves were used to compare the diagnostic performance. RESULTS: The final pathological diagnoses included 52 malignant and 22 benign tumours. High SUVmax (>4.8) and large size (>13 cm) favoured malignancy, and yielded a diagnostic accuracy and AUC of 64.9%, 0.820±0.059, and 68.9%, 0.738±0.061, respectively. In a subgroup of RPMs with a fat component, both SUVmax and size were significantly different between benign and malignant RPM, which yielded a diagnostic accuracy and AUC of 91%, 0.977±0.024 (cut-off, 1.9 cm) and 87.9%, 0.865±0.072 (cut-off, 13 cm), respectively. In a subgroup without a fat component, only SUVmax was significantly different with an accuracy of 90.2% and AUC of 0.919±0.043. The optimal diagnostic flow by combining SUVmax and tumour size after dividing patients into two groups according to the presence of fat showed a sensitivity of 90.4%, a specificity of 95.5%, and an accuracy of 91.9%. CONCLUSIONS: The combination of SUVmax and size according to the presence of a fat component may be the optimal PET/CT diagnostic criteria for distinguishing benign and malignant RPMs.

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.

Lactococcus lactis KR-050L inhibit IL-6/STAT3 activation.

AIMS: The purpose of this study was to investigate IL-6/STAT3 inhibitory activity using lactic acid bacteria (LABs) isolated from Gajuknamu kimchi. METHODS AND RESULTS: Six LABs were isolated from Gajuknamu kimchi and identified through 16S rRNA sequencing. Among them, the culture broth of Lactococcus lactis KR-050L inhibited IL-6-induced STAT3 luciferase activity. Fifteen compounds were isolated from the EtOAc extract of culture broth though column chromatography and preparative high-performance liquid chromatography, and they were identified as 2,5-diketopipperazine structures by spectroscopic analyses (MS, 1 H- and 13 C-NMR). They also showed inhibitory activities on IL-6-induced STAT3 activation, and showed the different in activity according to the presence of a phenylalanine residue, hydroxyl groups and isometric structure. CONCLUSIONS: The six new LABs isolated from Gajuknamu kimchi, and Lc. lactis KR-050L was selected as candidate IL-6/STAT3 inhibitors. The activity levels of 15 2,5-DKPs isolated from Lc. lactis KR-050L were verified. SIGNIFICANCE AND IMPACT OF THE STUDY: This study constitutes the first attempt to isolate various LABs from Gajuknamu kimchi and to discover IL-6/STAT3 inhibitors in the EtOAc extract of Lc. lactis KR-050L culture broth. Moreover, our data provide useful biochemical information regarding the commercialization of Lc. lactis isolated from Gajuknamu kimchi as an approach to use functional foods for the treatment of various diseases via IL-6/STAT3 activation.

Risk factors for contact lens-related microbial keratitis in Singapore.

PURPOSE: To investigate independent risk factors for contact lens-related microbial keratitis in Singapore and estimate their impact on disease load. METHODS: Cases were contact lens wearers presenting to Singapore National Eye Centre with microbial keratitis between 2008 and 2010. Community contact lens wearers were recruited as controls. All wearers completed a previously validated questionnaire describing contact lens wear history, hygiene and compliance habits, and demographics. Risk factors significant in univariate analysis (P<0.2) were evaluated in a multivariate model. RESULTS: In all, 58 cases of microbial keratitis and 152 contemporaneous controls were identified. When controlling for other variables, Chinese had a 7 × lower risk compared with other races (95% CI: 2.3-21.3, P=0.001). Those aged between 25 and 44 years were at 3 × increased risk compared with younger wearers (95% CI: 1.1-9.6, P=0.04). Occasional overnight contact lens wear (less often than one night per week) was associated with a 4 × higher risk (95% CI: 1.2-15.4, P=0.03) compared with daily use. Not washing hands before handling was associated with a 13 × increased risk (95% CI: 1.9-84.8, P=0.008). Use of multipurpose solution A carried a 16 × higher risk compared with hydrogen peroxide (95% CI: 1.5-174.0, P=0.02). The combined PAR% for modifiable risk factors (occasional overnight wear, not washing of hands, and MPS A) was 82%. CONCLUSIONS: Consistent with previous findings, independent risk factors for contact lens-related microbial keratitis include poor hand hygiene, occasional overnight wear, and type of lens care solution. Prolonged overnight or extended contact lens use was infrequent in this population.

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.

Mitochondrial ATP transporter Ant2 depletion impairs erythropoiesis and B lymphopoiesis.

Adenine nucleotide translocases (ANTs) transport ADP and ATP through mitochondrial inner membrane, thus playing an essential role for energy metabolism of eukaryotic cells. Mice have three ANT paralogs, Ant1 (Slc25a4), Ant2 (Slc25a5) and Ant4 (Slc25a31), which are expressed in a tissue-dependent manner. While knockout mice have been characterized with Ant1 and Ant4 genes, which resulted in exercise intolerance and male infertility, respectively, the role of the ubiquitously expressed Ant2 gene in animal development has not been fully demonstrated. Here, we generated Ant2 hypomorphic mice by targeted disruption of the gene, in which Ant2 expression is largely depleted. The mice showed apparently normal embryonic development except pale phenotype along with a reduced birth rate. However, postnatal growth was severely retarded with macrocytic anemia, B lymphocytopenia, lactic acidosis and bloated stomach, and died within 4 weeks. Ant2 depletion caused anemia in a cell-autonomous manner by maturation arrest of erythroid precursors with increased reactive oxygen species and premature deaths. B-lymphocyte development was similarly affected by Ant2 depletion, and splenocytes showed a reduction in maximal respiration capacity and cellular ATP levels as well as an increase in cell death accompanying mitochondrial permeability transition pore opening. In contrast, myeloid, megakaryocyte and T-lymphocyte lineages remained apparently intact. Erythroid and B-cell development may be particularly vulnerable to Ant2 depletion-mediated mitochondrial dysfunction and oxidative stress.

Intraoperative esophagoscopy provides accuracy and safety in video-assisted thoracoscopic enucleation of benign esophageal submucosal tumors.

Benign esophageal tumors are rare; complete surgical resection is essential for the management of the submucosal tumors. Larger, symptomatic, or non-diagnostic lesions should be resected for both diagnostic and therapeutic indications. Video-assisted thoracic surgery has become a popular treatment in the field of thoracic surgery; however, thoracoscopic esophageal surgery may lead to an increase in operative complications. The effect and safety of thoracoscopic surgery for esophageal submucosal lesions were evaluated. A retrospective study evaluated patients undergoing thoracoscopic treatment of benign submucosal tumors. Between March 2011 and December 2013, 17 patients underwent thoracoscopic resection of benign submucocal tumors. Intraoperative esophagoscopy was performed for tumor localization by transillumination and confirmation of mucosal integrity after enucleation in every patient. Median patient age was 47 years (range 30-65). The median surgery time was 170 minutes (range 80-429). The median tumor size was 3.8 cm (range 1.3-9). The median hospital stay was 4 days (range 2-12). There were 16 leiomyoma and 1 neurogenic tumor. There was one case of conversion to thoracotomy because of residual tumor after enucleation. Mucosal injuries occurred in three patients, two accidentally and one intentionally; each patient was treated with primary repair and confirmed integrity with flexible esophagoscopy at operating room. The small sized tumor with intraoperative esophagoscopy could be localized. Esophagoscopic assistance was necessary in eight patients to have better idea where to make myotomy. There were no major morbidities such as postoperative leakage or mortality. Esophageal submucosal tumors can be treated safely with thoracoscopic surgery. However, intraoperative esophagoscopy allows accurate tumor localization, direction of esophageal access incision, and decreases complications during VATS enucleation of esophageal submucosal tumors.

Suicide prevention program for at-risk groups: pointers from an epidemiological study.

OBJECTIVES: The aim of this paper is to identify at-risk groups for a focused suicide prevention program for Malaysia. METHODS: Data from 20,552 persons aged 16 years and above (males 45.9%), was obtained using stratified, random sampling in a national survey of psychiatric morbidity using locally validated General Health Questionnaire (GHQ-28) which included questions on suicidal ideation. RESULTS: The overall prevalence of suicidal ideation (SI) was 6.3%, CI 6.1-6.8 (n=1288). Logistic regression analysis was performed with age, ethnicity, gender, urban/rural residence, age group, marital status, household income, type of household, presence of chronic pain, social dysfunction, somatic, anxiety or depressive symptoms, obesity, and chronic medical illnesses as independent variables. Only Insomnia, Religion, Marital Status, Depression, Social Dysfunction and Anxiety were seen to be significant predictors. Prevalence of SI was significantly higher among Indians (11.0%, CI 9.5-12.5), especially those of the Hindu faith (12.2%, CI 10.5-14.0), Chinese (9.7%, CI 8.8-10.7) and those having depressive symptoms. CONCLUSION: In a developing country with competing priorities, prudent allocation of resources requires focusing suicide prevention efforts on treating depression in vulnerable groups.

The clinical characteristics of gastroesophageal reflux disease in patients with laryngeal symptoms who are referred to gastroenterology.

The prevalence of gastroesophageal reflux disease (GERD) has increased recently in Asia-Pacific countries. However, little is known about its prevalence and clinical characteristics in GERD patients with atypical symptoms in Asia. The aim of this study was to investigate the clinical characteristics of GERD in patients who had laryngeal symptoms in Korea. Data were gathered retrospectively from patients who presented with atypical symptoms, such as throat discomfort, globus pharyngeus, hoarseness, and chronic cough. They underwent a 24-hour ambulatory intraesophageal pH monitoring and filled in a validated reflux questionnaire. Overall, 128 patients (36 men and 92 women) with laryngeal symptoms were included. Of these 128, 43 patients (34%) had erosive esophagitis or pathological reflux from 24-hour ambulatory pH monitoring, and 24 (19%) had a positive Bernstein test or positive symptom index from 24-hour pH monitoring. Sixty-one patients (48%) had no evidence of reflux esophagitis on upper endoscopy and pathological acid reflux on 24-hour pH monitoring. Fifty-six patients (44%) had weekly heartburn or regurgitation. Typical symptoms and dyspepsia were significantly more common in patients with GERD who had laryngeal symptoms than non-GERD. Fifty-two percent of patients had laryngeal symptoms that were associated with GERD. The presence of typical reflux symptoms and dyspepsia are risk factors for GERD in patients who present with laryngeal symptoms.

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.