Background: Iron deficiency (ID) and hemoglobinopathies are highly prevalent in Southeast Asia. Accurate estimation of reference intervals (RIs) for red cell parameters is complicated by the need to exclude individuals with these conditions from the reference population. Indirect RI estimations using machine learning could help overcome these challenges. Methods: We developed a binary classification model using eXtreme Gradient Boosting (XGB) to distinguish normal individuals from those with ID, hemoglobinopathies, or other anemias. The model was trained on an annotated dataset comprising 5,520 complete blood count (CBC) results and validated with a holdout dataset of 2,367 CBC results. An independent dataset of 64,100 CBC results was used to identify individuals predicted to be normal, from which RIs were estimated using the refineR algorithm. Results: The XGB model achieved an area under the ROC of 0.97 (95% confidence interval: 0.96–0.97) for distinguishing between individuals with normal versus abnormal values. Among individuals within the independent dataset, 40,300 (62.9%) were predicted to be normal. The refineR-based reference limits (RLs) derived from this subset approximated those obtained through a direct approach. Improvements in the accuracy of indirect RL estimates were most evident for hematocrit, hemoglobin, and red cell concentrations. Conclusions Combining XGB with refineR to indirectly derive RIs for red cell parameters improved the accuracy and yielded results comparable with those of directly derived RIs. A further benefit was the capacity to generate sex- and age-specific ranges, which has remained difficult to achieve through direct approaches.

Purpose: This systematic review evaluated the diagnostic performance of optical coherence tomography (OCT) forthe early detection of oral cancer, particularly emphasizing sensitivity, specificity, and overall diagnostic accuracy. Materials and Methods: A comprehensive literature search was conducted across PubMed, ScienceDirect, and Wiley Online Library covering publications from 2015 to 2025, supplemented by manual hand-searching of relevant references. Studies were selected using the Population, Intervention, Comparison, Outcome, Study Design (PICOS) framework. Eligible studies evaluated the diagnostic accuracy of OCT using histopathology as the reference standard. Risk of bias was assessed using the QUADAS-2 tool, and the review methodology followed PRISMA 2020 and PRISMA-DTA guidelines. The review protocol was registered in PROSPERO (CRD420251112254). Results: Seven studies met the predefined inclusion criteria. OCT demonstrated high diagnostic performance (sensitivity: 81.5%-100%, specificity: 68.8%-100%), with diagnostic accuracy reaching up to 100% in certain settings. Studies that incorporated machine learning approaches, including convolutional neural networks and support vector machines, consistently achieved superior diagnostic performance compared with conventional OCT interpretation alone. Overall methodological quality was generally low, with several studies exhibiting moderate tohigh risk of bias in specific domains. Conclusion OCT, particularly when augmented with artificial intelligence, demonstrates high diagnostic accuracy as anon-invasive imaging modality for the early detection of oral cancer. Its capability to identify dysplastic and malignant changes at the microstructural level offers meaningful diagnostic advantages over conventional examination methods.Nevertheless, larger-scale studies employing standardized protocols are required to confirm its clinical utility and support integration into routine oral cancer screening and diagnostic pathways.

Introduction: Cardiovascular disease (CVD) is a major cause of global mortality, including Brunei Darussalam. Health literacy plays an important role in the management of CVD. It is not clear how much patients could understand, judge and apply CVD knowledge in the management of their condition after completion of a cardiac rehabilitation programme at the Raja Isteri Pengiran Anak Saleha Hospital, a tertiary referral centre in Brunei Darussalam. Materials and Methods: This was a cross - sectional study of cardiac rehabilitation patients who completed Phase II of the programme over a four-month period . Patients were recruited through convenience sampling methods. A validated questionnaire was used to assess participants ’ knowledge, attitude and practice (KAP) on CVD. The data were computed using R v.3.4.4. and analysed using descriptive and inferential statistics. A p<0.05 was considered to be statistically significant. Results: Of the total (n=120) participants recruited, 89.2% were males. 90.0% were below 70 years of age and 82.5% were Malay. 54.2% achieved the highest level of education at secondary school. Hypercholesterolemia and hypertension were prevalent; accounting for 71.7% and 70.0% respectively, while obesity and diabetes mellitus accounted for 47.5% and 39.7% respectively. The mean (standard deviation) scores for knowledge, attitude and practice were 66.86 (3.71) out of 75, 57.83 (4.47) out of 65, and 33.11 (3.65) out of 44, respectively. There was a significant difference in the CVD knowledge scores between different levels of education (p=0.024). Conclusions: There is a good level of CVD knowledge, attitude and practice in cardiac rehabilitation patients post -Phase II of the programme. Delivery of education sessions in Phase II of the programme in consideration of the varied educational backgrounds of the participants may help ensure everyone can benefit equally

Introduction: The COVID -19 pandemic significantly impacted the mental health and wellbeing of healthcare workers worldwide. This study examined the prevalence and predictors of self -reported mental health problems, specifically depression, anxiety, stress, and burnout among government healthcare professionals in Brunei Darussalam during the second and subsequent waves of the pandemic. Materials and Methods : A cross -sectional online survey was distributed to all government healthcare workers employed by the Ministry of Health in Brunei Darussalam. The survey collected sociodemographic information and applied two validated tools: the Depression Anxiety Stress Scale 21 -item version (DASS -21) to assess the depression, anxiety, and stress, and the Oldenburg Burnout Inventory (OLBI) to measure burnout. Results : Of 1,759 invited healthcare workers, 704 responded (response rate 40.0%). The prevalence of common mental health problems and burnout were 32.4% and 71.7%, respectively. Older age was protective against common mental health problems. Performing clinical duties outside one's training scope, and direct involvement in managing COVID -19 patients were significant predictors of common mental health problems. Expatriate staff had significantly lower odds of burnout compared to Bruneian nationals. Shift work and additional administrative duties independently predicted burnout. A history of mental health problems and difficulty accessing mental health support were strongly associated with both outcomes. Conclusions : This study identified a substantial burden of depression, anxiety, stress, and burnout among government healthcare professionals in Brunei Darussalam, with distinct vulnerable subgroups. These findings highlight the need for targeted mental health interventions, improved access to support services, and systemic workplace strategies to safeguard the wellbeing of the healthcare workforce. The Brunei International Medical Journal (BIMJ) is a peer -reviewed official publication of the Ministry of Health and Universiti Brunei Darussalam, under the auspices of the Clinical Research Unit, Ministry of Health, Brunei Darussalam. The BIMJ publishes articles ranging from original research papers, review articl es, medical practice papers, special reports, audits, case reports, images of interest, education and technical/innovation papers, editorials, commentaries, and letters to the Editor. Topics of interest include all subjects related to clinical practice and research in all branches of medicine, both basic and clinical, including topics related to allied health care fields. The BIMJ welcome s manuscripts from contributors but usually solicits review articles and special reports. Proposals for review papers can be sent directly to the Managing Editor. Please refer to the contact inf ormation of the Editorial Office. DISCLAIMER: All articles published, including editorials and letters, represent the opinions of the contributors and do not reflect the o fficial views or policies of the Clinical Research Unit, the Ministry of Health, or the institutions with which the contributors are affiliated, unless clearly stated. The appearance of advertisements does not constitute an endorsement by the Clinical Research Unit or the Ministry of Health, Brunei Darussalam. Furthermore, the publisher cannot accept responsibility for the c orrectness or accuracy of the advertisers' text, claims, or any bimjonline@gmail.com www.bimjonline.com Author Details: 1 Psychiatry Services, Ministry of Health, Brunei Darussalam 2 Dorset Healthcare University NHS Foundation Trust, United Kingdom 3 Community Psychology Division, Ministry of Health, Brunei Darussalam 4 PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam 5 Department of Forensic Psychiatry, NHS Forth Valley, United Kingdom 6 Primary Health Care, Ministry of Health, Brunei Darussalam 25 Mikhail SOLIMAN1,2*, Fauziyyah MANAP3, Nur Syahirah CHUA3, Rina RAHMAD3, Hjh Rozailah RAHMAN3, Hanif ABDUL RAHMAN4, Najib NAIBI6, Kartini TUDIN1, Hilda HO1,5

Introduction: Cardiovascular disease (CVD) is a major cause of global mortality, including Brunei Darussalam. Health literacy plays an important role in the management of CVD. It is not clear how much patients could understand, judge and apply CVD knowledge in the management of their condition after completion of a cardiac rehabilitation programme at the Raja Isteri Pengiran Anak Saleha Hospital, a tertiary referral centre in Brunei Darussalam. Materials and Methods: This was a cross - sectional study of cardiac rehabilitation patients who completed Phase II of the programme over a four-month period . Patients were recruited through convenience sampling methods. A validated questionnaire was used to assess participants ’ knowledge, attitude and practice (KAP) on CVD. The data were computed using R v.3.4.4. and analysed using descriptive and inferential statistics. A p<0.05 was considered to be statistically significant. Results: Of the total (n=120) participants recruited, 89.2% were males. 90.0% were below 70 years of age and 82.5% were Malay. 54.2% achieved the highest level of education at secondary school. Hypercholesterolemia and hypertension were prevalent; accounting for 71.7% and 70.0% respectively, while obesity and diabetes mellitus accounted for 47.5% and 39.7% respectively. The mean (standard deviation) scores for knowledge, attitude and practice were 66.86 (3.71) out of 75, 57.83 (4.47) out of 65, and 33.11 (3.65) out of 44, respectively. There was a significant difference in the CVD knowledge scores between different levels of education (p=0.024). Conclusions: There is a good level of CVD knowledge, attitude and practice in cardiac rehabilitation patients post -Phase II of the programme. Delivery of education sessions in Phase II of the programme in consideration of the varied educational backgrounds of the participants may help ensure everyone can benefit equally

Introduction: The COVID -19 pandemic significantly impacted the mental health and wellbeing of healthcare workers worldwide. This study examined the prevalence and predictors of self -reported mental health problems, specifically depression, anxiety, stress, and burnout among government healthcare professionals in Brunei Darussalam during the second and subsequent waves of the pandemic. Materials and Methods : A cross -sectional online survey was distributed to all government healthcare workers employed by the Ministry of Health in Brunei Darussalam. The survey collected sociodemographic information and applied two validated tools: the Depression Anxiety Stress Scale 21 -item version (DASS -21) to assess the depression, anxiety, and stress, and the Oldenburg Burnout Inventory (OLBI) to measure burnout. Results : Of 1,759 invited healthcare workers, 704 responded (response rate 40.0%). The prevalence of common mental health problems and burnout were 32.4% and 71.7%, respectively. Older age was protective against common mental health problems. Performing clinical duties outside one's training scope, and direct involvement in managing COVID -19 patients were significant predictors of common mental health problems. Expatriate staff had significantly lower odds of burnout compared to Bruneian nationals. Shift work and additional administrative duties independently predicted burnout. A history of mental health problems and difficulty accessing mental health support were strongly associated with both outcomes. Conclusions : This study identified a substantial burden of depression, anxiety, stress, and burnout among government healthcare professionals in Brunei Darussalam, with distinct vulnerable subgroups. These findings highlight the need for targeted mental health interventions, improved access to support services, and systemic workplace strategies to safeguard the wellbeing of the healthcare workforce. The Brunei International Medical Journal (BIMJ) is a peer -reviewed official publication of the Ministry of Health and Universiti Brunei Darussalam, under the auspices of the Clinical Research Unit, Ministry of Health, Brunei Darussalam. The BIMJ publishes articles ranging from original research papers, review articl es, medical practice papers, special reports, audits, case reports, images of interest, education and technical/innovation papers, editorials, commentaries, and letters to the Editor. Topics of interest include all subjects related to clinical practice and research in all branches of medicine, both basic and clinical, including topics related to allied health care fields. The BIMJ welcome s manuscripts from contributors but usually solicits review articles and special reports. Proposals for review papers can be sent directly to the Managing Editor. Please refer to the contact inf ormation of the Editorial Office. DISCLAIMER: All articles published, including editorials and letters, represent the opinions of the contributors and do not reflect the o fficial views or policies of the Clinical Research Unit, the Ministry of Health, or the institutions with which the contributors are affiliated, unless clearly stated. The appearance of advertisements does not constitute an endorsement by the Clinical Research Unit or the Ministry of Health, Brunei Darussalam. Furthermore, the publisher cannot accept responsibility for the c orrectness or accuracy of the advertisers' text, claims, or any bimjonline@gmail.com www.bimjonline.com Author Details: 1 Psychiatry Services, Ministry of Health, Brunei Darussalam 2 Dorset Healthcare University NHS Foundation Trust, United Kingdom 3 Community Psychology Division, Ministry of Health, Brunei Darussalam 4 PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam 5 Department of Forensic Psychiatry, NHS Forth Valley, United Kingdom 6 Primary Health Care, Ministry of Health, Brunei Darussalam 25 Mikhail SOLIMAN1,2*, Fauziyyah MANAP3, Nur Syahirah CHUA3, Rina RAHMAD3, Hjh Rozailah RAHMAN3, Hanif ABDUL RAHMAN4, Najib NAIBI6, Kartini TUDIN1, Hilda HO1,5

Introduction: Leydig cells (LCs) are the principal source of testosterone in males, underpinning male reproductive health and androgendependent physiology. Precise isolation of viable human LCs is essential for mechanistic steroidogenesis research and cell-based therapeutic development. Existing protocols rely on density-gradient centrifugation, which is technically demanding and often compromises yield and viability. Here, we describe a simplified density-gradient-free approach using differential adhesion to enrich functional human LCs from testicular tissue. Methodology: Human testicular fragments (~5 mm³) were minced and enzymatically digested with collagenase IV (2 mg/mL) at 37°C for 20 min under gentle agitation (100 RPM). The suspension was filtered (45 µm) and plated onto poly-L-lysine-coated T25 flasks. After 24 hours, non-adherent cells were removed by PBS washing. Viability exceeded 90% by trypan blue exclusion. Cells were maintained in DMEM/F12 with 10% FBS, 1% Antibiotic-Antimycotic, and 10 ng/mL luteinizing hormone (LH) to preserve the mature LC phenotype. Characterization employed immunofluorescence and flow cytometry using antibodies against SF-1, StAR, LHCGR, PDGFRA, and TEM-1. Testosterone secretion was quantified by ELISA under basal conditions and LH-stimulated conditions (10 ng/mL). Results: The protocol yielded ~1.25 × 10⁶ LCs per gram of tissue with >80% purity. Adherent HLCs displayed dense cytoplasmic lipid granules and intercellular networks consistent with active steroidogenesis. Flow cytometry confirmed 84.7% StAR⁺ cells, indicative of a robust steroidogenic population. A distinct progenitor subpopulation (PDGFRα⁺/TEM-1⁺) comprising ~28% of primary cultures, suggests retention of regenerative capacity. Basal testosterone secretion averaged 8.88 ng/mL per 24 hours, confirming preserved functional activity post-isolation. Conclusion This differential-adhesion protocol efficiently isolates functional human LCs without density-gradient media. Multimodal validation integrating immunofluorescence, flow cytometry, and ELISA confirms both phenotypic identity and steroidogenic competence, providing a reproducible and accessible platform for LC research and translational applications in male hypogonadism and androgen replacement.
Leydig Cells

Introduction: Primary aldosteronism (PA), most commonly caused by aldosterone-producing adenomas (APAs), represents the leading form of surgically curable secondary hypertension. While genomic studies have elucidated the mutational landscape of APAs, the spatial organisation and functional role of immune populations across APAs, aldosterone-producing micronodules (APMs), and adjacent adrenal cortex remain poorly defined at single-cell resolution. Methodology: Single-cell RNA sequencing (scRNA-seq) was integrated with spatial transcriptomics in APAs and paired adjacent adrenal cortex, complemented by immunohistochemical (IHC) validation. Immune populations were spatially mapped using canonical markers (CD14, CD68, CD163, HLA-DR, CD8A, and CD4) across defined adrenocortical regions. Results: The adrenal microenvironment in PA demonstrates structured immune organisation rather than passive infiltration. CD14+ monocyte-lineage cells localize intraparenchymally within APAs (n = 10), intercalating between CYP11B2+ aldosterone-producing cells and forming a pattern distinct from perivascular immune niches. scRNA-seq further identified a transcriptionally distinct CD14+ population within the zona reticularis (zR) that co-expresses steroidogenic markers (CYB5A, SULT2A1, TSPAN12) while lacking canonical monocyte transcripts. IHC supported this observation, demonstrating CD14 expression within adrenocortical zR parenchymal cells (n = 5). In parallel, CD4 and HLA-DRA exhibited diffuse cytoplasmic staining within zR parenchymal cells in the absence of classical macrophage marker coexpression (CD68), suggesting non-canonical or context-dependent expression within steroidogenic compartments. CD68+ and CD163+ macrophages were sparsely distributed across APA, APM and adjacent cortex, consistent with lowdensity tissue-resident populations, while CD8A+ cytotoxic lymphocytes were enriched in APAs and APMs with diffuse parenchymal cytoplasmic staining of CD8A additionally observed within the zR. Conclusion These findings reveal a previously unrecognized spatially organised immune-steroidogenic interface within the adrenal cortex. The presence of immune-associated transcriptional and protein signatures within zR cells suggests potential functional plasticity of steroidogenic cells, possibly extending to antigen presentation-related pathways, warranting further mechanistic investigation
Hyperaldosteronism ; Humans

Introduction: Capivasertib is a selective oral AKT inhibitor approved for hormone receptor-positive, HER2-negative advanced breast cancer with AKT pathway mutations. As AKT is integral to insulin signaling, its inhibition predisposes patients to hyperglycemia. We report a case of severe capivasertib-induced hyperglycemia with profound insulin resistance in a non-diabetic patient. Case: A 56-year-old female with metastatic breast cancer (ER/ PR-positive, HER2-negative, AKT1- and ESR1-mutated, TMB-high) presented with severe hyperglycemia following capivasertib initiation. She had no prior diabetes history, with a baseline hemoglobin A1c of 5.6%. Her first cycle (200 mg twice daily, 7 April 2025) was uncomplicated metabolically. The second cycle was escalated to 400 mg twice daily on 21 April 2025. By Day 3, blood glucose rose significantly. Premixed insulin 20 units failed to achieve glycemic control, necessitating intravenous insulin infusion. Despite escalation to 30 units per hour, euglycemia could not be achieved. Notably, there was no biochemical evidence of diabetic ketoacidosis or hyperosmolar hyperglycemic state, and the patient remained hemodynamically stable. No corticosteroids or other contributing medications were administered. Blood glucose normalized spontaneously approximately 36 hours after the last capivasertib dose, and all insulin was weaned and discontinued by 26 April 2025. She remained euglycemic without antidiabetic therapy thereafter. The patient and family opted for palliative care, and she passed away on 6 May 2025. Conclusion Capivasertib can precipitate severe, insulin-resistant hyperglycemia even in non-diabetic patients, without progression to overt hyperglycemic crisis. Spontaneous resolution upon drug cessation supports a direct drugmediated mechanism via AKT-disrupted insulin signaling. Clinicians should monitor glucose closely during therapy and consider drug cessation in refractory cases. Further studies are warranted to guide optimal glycemic management.
capivasertib ; Hyperglycemia ; Insulins

Introduction: Clinically important drug–drug interactions are a frequently overlooked cause of severe hypoglycemia in patients with type 2 diabetes mellitus (T2DM). Gliclazide is primarily metabolized via cytochrome P450 2C9 (CYP2C9), while fluconazole is a potent inhibitor of this enzyme.1,2 Concomitant administrations markedly increase gliclazide plasma concentration and prolong its hypoglycemic effect, substantially increasing the risk of severe and prolonged hypoglycemia. In some cases of refractory sulfonylureainduced hypoglycemia, octreotide may need to be considered early. Case: A 63-year-old Malay female with a 15-year history of T2DM on maximum-dose gliclazide (320 mg/day) presented with syncope and recurrent severe hypoglycemia 5 days after receiving a single oral dose of fluconazole 150 mg for a superficial fungal skin infection. Her other antidiabetic medications included metformin 1 g twice daily and vildagliptin 50 mg once daily. Her blood pressure on presentation was 151/74 mmHg, and her glucose level was 2.8 mmol/L. Her presentation was compounded by community-acquired pneumonia and acute kidney injury (estimated glomerular filtration rate 52 mL/min/1.73 m²). Biochemical evaluation excluded adrenal insufficiency, with normal serum cortisol (1,098 µg/dL), serum sodium (141 mmol/L), and serum potassium (4.6 mmol/L). Thyroid and liver function tests were normal. Despite repeated boluses of 50% dextrose and continuous infusion of 20% dextrose, recurrent hypoglycemia persisted for up to 48 hours after discontinuation of gliclazide, with glucose ranging from 1.7 to 5.1 mmol/L, reflecting prolonged sulfonylurea activity. Conclusion This case highlights a clinically significant yet preventable interaction between fluconazole and gliclazide, mediated through CYP2C9 inhibition, resulting in sustained hyperinsulinemic hypoglycemia. Gliclazide should be reduced or withheld prior to initiating fluconazole, and medication review should be performed at every consultation.
Fluconazole ; Gliclazide ; Hypoglycemia