We report a case of cavernous sinus thrombosis in a post-splenectomy male with underlying Haemoglobin E Thalassemia major. A 35-year-old man presented with a first episode of sudden onset of diplopia on lateral gaze for 1 week. He had no other ocular and systemic symptoms. There was no history of trauma or recent infection. However, he admitted that he was not compliant to his oral penicillin V and aspirin, which was prescribed to all post splenectomy patients. Unaided visual acuity in both eyes was 6/6. On examination, there was limited abduction over the left eye, suggestive of left lateral rectus palsy. Full blood count revealed leucocytosis with thrombocytosis. Magnetic resonance imaging, magnetic resonance angiography and magnetic resonance venography of the brain showed bulging of the left cavernous sinus, with a persistent focal filling defect, in keeping with left cavernous sinus thrombosis (CST). He was diagnosed with left isolated sixth nerve palsy secondary to aseptic cavernous sinus thrombosis with pro-thrombotic state post-splenectomy. He was started on subcutaneous fondaparinux and oral warfarin. His diplopia fully resolved after 1 month of treatment with complete resolution of CST on computed tomography venogram.
Haemoptysis is the clinical features of pulmonary tuberculosis (PTB) (32.5%) in Malaysia, in which if massive and left untreated it carries out a mortality risk of more than 50%. In the majority of cases, the main bleeder arises from the bronchial artery, with the pulmonary arterial circulation as a rare cause of bleeding, accounting for less than 10% of cases. Rasmussen aneurysm is a rare phenomenon following the weakening of the pulmonary artery wall resulting from adjacent cavitary tuberculosis. The sequelae which follow include pseudoaneurysm formation and subsequent rupture.
Horseshoe crab is one of the oldest existing living fossils comprising four main species today. Of these, Limulus Polyphemus is found in North America and the other three species, Tachypleus tridentatus, Tachypleus gigas and Carcinoscorpius rotundicauda are found in Southeast Asia. Horseshoe crabs play important roles in the regulation of the coastal ecology communities whereby the eggs serve as the main diet of shorebird species during the migrating season. Horseshoe crab is also seen as a versatile organism, useful in the biomedicine field particularly, as its blue blood has been widely integrated to be used for endotoxin tester in vaccines, drugs and injectables. Researchers have explored a material called perivitelline fluid (PVF) from the egg of a fertilized horseshoe crab which is rich in important proteins and amino acids that are crucial for embryogenesis. Previous studies have shown that PVF has the ability to enhance cell growth and differentiation as well as in promoting generation of certain organs. Testing of PVF on many types of cells has shown positive results and hence, it is suggested that PVF could be used as a supplement to support cell growth in future. Highlighting the horseshoe crab as a living fossil, this review brings out the relevance of the blue blood and PVF of the horseshoe crab as sources benefitting molecular research.
The aim of this study was to design and systematically optimize
triclosan loaded nanoparticles (TCS-loaded NPs) formulation for the treatment
of periodontal disease. Triclosan (TCS) is a broad spectrum antimicrobial
agent that has been used in the treatment of the disease. The free drug has
poor aqueous solubility and therefore may encounter permeability problems
when applied to the oral cavity. Resolution IV model of Design-Expert®
software (version 10) was used for the design of experiment and optimization
of TCS-loaded NPs. The nanoparticles (NPs) were prepared using the solvent
displacement method. Effect of factors that were investigated include drugpolymer ratio, surfactant concentration, stirring speed, stirring duration, and
drug-polymer injection rate. Particle size, zeta potential, polydispersity index
(PDI) and entrapment efficiency (EE) were the critical quality attributes
selected for the study. Desirability function determined by the software for
optimized TCS-loaded NPs was 0.704. The observed particle size, PDI, zeta
potential and EE of the optimized TCS-loaded NPs was found to be 135 ± 2.3
nm, 0.1 ± 0.012, -30 ± -4 mV and 75 ± 6%, respectively. It was found that
particle size increases by elevating the concentration of polymer and
decreases with an increase in surfactant concentration and stirring speed.
Zeta potential was found to increase when surfactant concentration was
reduced. Both surfactant concentration and drug to polymer ratio were found
to negatively affect PDI while % EE was positively influenced by the increase
in polymer concentration and decrease in surfactant concentration. The use of
Design-Expert®
software helped in identifying suitable levels of critical quality
parameters for preparing improved NPs formulation for delivery of TCS into
the periodontal pocket.
The presence of retinal vasculitis in patients with pulmonary tuberculosis is not uncommon. However, asymptomatic presentations are quite rare. Here, we present a case of 25-year-old Malay gentleman with pulmonary tuberculosis, who was referred for an eye assessment following initiation of anti-tuberculosis drugs. His vision was good; he had no other symptoms despite having retinal neovascularization, pre-retinal haemorrhages and healed choroiditis at the fundus of the left eye. Fundus fluorescein angiography showed multiple areas of capillary fallouts at the superotemporal quadrant of the left eye with leakage from the retinal neovascularization. He was treated with laser retinal photocoagulation and oral steroids for 6 weeks, while the anti-tuberculosis drugs were continued for 9 months. Subsequent follow-ups showed regression of the neovascularization. He has remained asymptomatic since his initial visit to the eye clinic.
Sino-nasal osteoma is a common benign tumour of paranasal
sinuses and usually asymptomatic. Here, we presented a case of a huge sinonasal osteoma. Despite the large size of the tumour, the only presentation
was epiphora. There were no headache, facial pain or diplopia. Nasal
obstruction only occurred after involvement of the nasal cavity. In diagnosing
aetiology of the epiphora, sino-nasal pathology needed to be ruled out after
excluding ocular causes. Multidisciplinary approach between otolaryngology
(ORL) team and ophthalmology team was essential in managing the case.
The tumour was successfully removed surgically via endoscopic approach;
and dacryocystorhinostomy (DCR) was performed to alleviate the epiphora.
Acute lymphoblastic leukemia (ALL) is the most common
childhood leukaemia. It is a malignant neoplasm caused by the proliferation of
poorly differentiated precursors of the lymphoid cells. It is relatively
uncommon in adult. In adult ALL, central nervous system (CNS) involvement
is associated with poor prognosis. The incidence of CNS involvement has
been reported between 7% and 15 %. We report a case of optic nerve
infiltration in ALL in a 49 years old gentleman. He was diagnosed with
precursor-B ALL. He was treated with chemotherapy and CNS prophylactic
regime. He presented with sudden left eye loss of vision for one-day duration
with history of right eye inferior visual field loss for the past three months. His
visual acuity was no perception to light on the left eye and 6/9 on the right
eye. There was marked left relative afferent pupillary defect. The right eye
showed decreased in optic nerve function with inferior visual field defect.
Anterior segment examination was unremarkable in both eyes. Left optic disc
appeared normal but the right optic disc was pale. Blood investigation
showed no sign of infection or haemoconcentration. Cerebral spinal fluids
examination revealed abundant of white cells and blast cells. Magnetic
resonant imaging showed bilateral optic nerve enhancement suggesting of
bilateral optic nerves infiltration. He was started on a new regime of
chemotherapy followed by cranial radiotherapy. Unfortunately, he succumbed
to death due to septicaemia. There are variations in clinical presentation of
optic nerve infiltration in leukaemic patients. Normal appearance of optic disc
may not exclude the possibility of infiltration by malignancy. Assessment of
the optic nerve function and imaging is helpful for the detection of leukaemic
infiltration. Early detection of optic nerve infiltration is important for initiation or
change of therapy to prevent mortality.
Blood donation in Malaysia is practised as voluntary non-remunerated. However, recruiting and retaining blood donors remain a challenge in the transfusion service. The main aim of this study was to understand the factors affecting the return of first-time blood donors. This was a retrospective study involving 480 first-time temporarily deferred whole blood donors from National Blood Centre (NBC), Kuala Lumpur. Data of donors who were deferred from 2010 to 2014 were extracted from the Blood Bank Information System. Deferred blood donors were categorised into two main groups, namely, a group of donors who returned for blood donation and a group that did not return for the donation. Each blood donor was contacted personally via telephone. Donors who returned were younger (p < 0.001), with females in a higher proportion (61.3%) compared to males (38.8%) (p < 0.001). Singles (68.3%) were more likely to return for donation compared to married donors (31.7%) (p < 0.001). Donors who lived in urban areas were more likely to return for donation compared to donors who lived in rural areas (34.6%) (p < 0.005). The most common factor that had motivated these donors to return was self-satisfaction (29.9%), while the most common factor that hindered them from returning for donation was the lack of time (28.50%). As a conclusion, more awareness and education regarding regular blood donation should be considered to donors from a rural areas. Additionally, mobile blood donation drives should be made easier for blood donors who have a busy lifestyle.
Chromosomal abnormalities (CA) can affect numerical or structural compositions of chromosomosal DNA leading to a diversity of clinical phenotypic presentations. Awareness of prenatal diagnosis and genetic counselling have improved with advancing medical research but CA remain prevalent as its aetiology is unknown. The objective of this study is to determine the frequencies of various CA in the principle region of north-western Malaysia and compare this data to previous reports to ascertain if statistical differences exist. Karyotype analyses performed at the Genetics Laboratory, Advanced Diagnostic Laboratory (ADL) during the first 5-years of cytogenetic services, totalling 1461 cases, were assessed in this report. Cases suspected of CA were initially diagnosed by clinicians and detailed clinical and family histories were recorded. Peripheral blood lymphocytes of patients were collected and cultured in vitro for acquisition of karyotype by standardized G-banding technique. Fluorescence in situ hybridization (FISH) was conducted in cases suspected of to be DiGeorge, Prader-Willi, Angelman and Williams syndrome. Of the total samples (1805) received and cultured, 1669 (92.46%) successfully yielded results. Abnormal outcomes were observed in 495 cases (29.66%) whereby pronounced majority of cases 299 (68.42%) were Down syndrome. This is followed by Edward, Turner and Patau syndrome, in order of frequency. Numerical CA appears to be prevalent accounting for 85.86% of cases. Structural CA accounted for 14.14% of total positive cases whereby the most common was deletions (34.29%) followed by translocations (20%), ring chromosomes (5.71%), Fragile X syndrome (4.29%), duplications (5.71%) and marker chromosomes (7.14%). The remainder of cases (22.86%) consisted of derivative chromosomes and other complex aberrations. The number of polymorphic variant cases were 27 (1.62%). The number of peripheral blood samples received has significantly increased from 14.3 per month in 2006 to 32.17 per month in 2011. Comparative analysis of our study to previous reports reveal statistical differences in the occurrence of several CA including Edward, Patau, Klinefelter and Fragile-X syndrome. Our experience with peripheral blood samples for cytogenetic analysis demonstrated a success rate of 92.46%. This showed an increase in clinicians validating patients’ diagnoses with karyotyping which is essential in confirming genetic anomalies with the goal to substantiate genetic counselling.
Introduction: Methylation of promoter region of p16 leading to gene silencing has been implicated ina wide range of malignancies including lymphomas. In diffuse large B cell lymphoma (DLBCL) particularly, a varying percentage of epigenetic inactivation of p16 promoter region was observed ranging from 16 -54%. However, quantitative analysis of p16 promoter methylation in DLBCL has not been extensively studied in Malaysia. Objective: This study aims to quantitatively analyse p16 methylation in DLBCL samples using pyrosequencing technique. Methods: Genomic DNA was extracted from 16 formalin-fixed paraffin-embedded lymphoma tissue blocks from patients diagnosed with DLBCL. Samples were retrieved from Hospital Tengku Ampuan Afzan, Pahang and Hospital Universiti Sains Malaysia, Kelantan. Primers were designed to amplify bisulfite-treated DNA targeting p16 promoter region. Methylation status of 7 CpG sites was determined by pyrosequencing. Results: All the 16 samples studied showed promoter methylation of p16. The range of mean methylation percentage was between 18 to 81%. Conclusion: The present study has successfully measured the level of methylation of p16 in all 7 CpG sites despite the limitation in sample size. Since p16 methylation is a common event in our series of DLBCL cases, it is worth including a larger sample size in future studies to increase the chance of finding a significant correlation with clinical parameters.
Thisstudy aim tocharacterize melt-derivedbioactive glass and to determinethe bioactive glass (BG) suitability for dental usagethrough proliferative activity assessment of stem cells from human exfoliated deciduous teeth (SHED)when exposed to bioactive glass conditioned medium. Bioglass 45S5 in mole percentages (46.13% SiO2, 26.91% CaO, 24.35% Na2O and 2.60% P2O5)was synthesizedthrough melt-derived and characterized usingX-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR)to confirm and identify its properties.SHEDwere used to evaluate the biocompatibility of 45S5 by exposing the cells to various concentration of BG-conditioned medium (1-10 mg/ml) using alamarBlue assay. The BG produced has an amorphous structureas shown by XRD analysis. TheSi-O-Si bending, asymmetric Si-O stretching and asymmetricSi-O-Si stretchingbands were observed in the BG structure supporting the presenceof silicate network. For alamarBlue assay, SHED cultured in BG-conditioned medium showed high proliferation rate when subjected to minimal powder content in the DMEM cell culture medium.Hence, it can be concluded that SHED cultured in lower powder content of the BG-conditioned media showedhigh proliferative activity suggesting the potential of the BG for dental usage.
The rare condition of neutrophils agglutination in-vitro may give inaccurate neutrophils count. We reported a case of a 71-year-old female admitted with a diagnosis of extended-spectrum beta-lactamase (ESBL) Escherichia Coli (E.coli) septicaemia secondary to the left lower limb cellulitis. Despite underlying infection, total white blood cell count (TWBC) and absolute neutrophil count remained in a normal range. An accidental finding of full blood picture (FBP) using K2 ethylenediaminetetraacetic acid (EDTA) tube presented numerous neutrophils agglutination. Further tests were carried out using citrated and heparinised tubes and tested at room temperature, 4 C, and 37 ͦC. The findings showed a significant reduction in neutrophils agglutination in both citrated and heparinised tubes, including when tested at room temperature (RT) and 4 ͦC. Surprisingly, at 37 ͦC, no neutrophil agglutination was observed. This indicates that temperature-dependent anti-neutrophil IgM antibody may be found in the patient's serum that reacted with the EDTA anticoagulant. In conclusion, white blood cells (WBC) agglutination has been associated with malignancy, sepsis, liver disease, and autoimmune disease. Thus, a baseline FBP is recommended, especially in these categories of patients to optimise their clinical management.
Xenobiotic substance released in the environment is a concern among the public at large. The example of this xenobiotic release into the environment is xenoestrogens. Xenoestrogens have the capability to bind to the estrogen receptors in the body even at low affinity. Food, pesticides and contraceptive pills are known sources of xenoestrogens. In this study, acute toxicity test was conducted to evaluate toxicity of synthetic estrogen such as estradiol to the embryo-larvae of zebrafish model. Morphological changes in the embryo-larvae of zebrafish were also observed. The parameters that were evaluated in acute toxicity study were half lethal concentration (LC50) and few apical endpoints such as coagulation of embryos, development of pericardial edema, and eyes size. Toxicity effect of the compound was evaluated in term of behavior activity of the larvae. Results showed that certain concentration of estradiol caused toxic effects to the embryo-larvae of the zebrafish (p
Cornea bee sting is a rare condition with mild to severe complications. We report a case series of three patients with cornea bee sting presented to a tertiary center. All patients sustained embedded stingers in the cornea stroma and presented within a few hours of injuries. All patients received topical antibiotics, topical steroids and removal of stingers. However, techniques of stinger removal and administration of the medications are among factors that contributed to different outcomes in these patients
Gene expression is the most fundamental level at which the
genotype gives rise to phenotype. The development of human salivary
exosomes has become one of the promising researches to improve cell-based
tissue engineering but their functions in human periodontal ligament fibroblast
(HPdLF) cells are not well studied. To study the effect of human salivary
derived exosomes on the gene expression of HPdLF cells. In vitro, HPdLF
cells were cultured for 24 hours with 10 µg/ml of human salivary exosomes.
Determination of gene expression levels of basic fibroblast growth factor
(bFGF) and collagen type I (COL1) in the presence and absence of human
salivary exosomes in HPdLF culture was performed using quantitative reverse
transcriptase polymerase chain reaction (RT-qPCR). Human salivary
exosomes significantly upregulated bFGF gene expression but not COL1
gene in HPdLF cells after 24 hours of culture. Human salivary exosomes are
able to upregulate bFGF gene in HPdLF cells. Thus, they might have potential
to be used as an alternative biomaterial in tissue engineering for periodontal
regeneration.
Abstract—The functions displayed by exosomes derived from saliva and
other body fluids have been established. This paper studied the stability of
human salivary exosome beginning from the collection mode, storage, and its
preservation methods. Unstimulated saliva samples were collected from
healthy subjects. Protease inhibitor was added into each samples and stored
under different temperatures and at varying periods of time. The exosomes
were isolated by ultracentrifugation and confirmed by using Western Blot.
Exosome morphology was inspected by Scanning Electron Microscope (SEM)
and the protein concentration was determined using the Protein (Bradford)
Assay. The exosome particle size distribution and concentration were
calculated using Nanoparticle Tracking Analysis (NTA). The protein assay
showed no significant differences in the exosome protein concentration values
for all conditions. Western Blot analysis also showed no differences in the
presence of exosome and all the samples were positive for protein CD63.
SEM analysis showed the fine shape of exosome which is round, in vesicle
form with the size ranging between 10 nm and 100 nm. NTA determined the
individual mean and the clumping exosome size was 203 nm. Human salivary
exosomes remained intact in the absence of protease inhibitor and in different
storage temperatures.
Tuberculosis, an ancient disease, still thrives today as the leading infection caused by Mycobacterium tuberculosis. Diagnosis of ocular tuberculosis poses a great challenge due to the varied clinical presentations. We report 3 cases of primary ocular tuberculosis with varied presentations: conjunctival abscess, sclera-uveitis and occlusive vasculitis. There were no symptoms suggestive of pulmonary tuberculosis in all cases. All patients presented with acute, unilateral painful red eye. The first case had good visual acuity (VA) OD (6/9) with a swollen upper lid, localized perilimbal-hemorrhagic conjunctival swelling superiorly, keratic precipitates and mild anterior chamber reaction. The posterior segment was normal. The second case had a VA of 6/60 OD. There was presence of conjunctival injection, keratic precipitates, posterior synechiae and anterior chamber reaction of 1+. A few days later, there was a progression to vitritis OU and hyperemic optic disc OD with choroidal folds, cystoid macula edema and a positive T sign on B scan ultrasonography. The third case had VA of 6/6 OU, AC reaction of 2+ OD. There was multiple peripheral choroiditis with peripheral vasculitis seen in the posterior segment OU. Fundus fluorescein angiography (FFA) showed peripheral periphlebitis in all 4 quadrants OU. All 3 cases had positive Tuberculin Skin Test (Mantoux test) results which were more than 20mm. Anti-tuberculous treatment was promptly started and all patients showed significant clinical improvement. This case series highlights the diverse clinical presentations of ocular tuberculosis. A high clinical index of suspicion led to prompt initiation of anti-tuberculous therapy which resulted in good clinical outcomes for all cases.
HbE/β-thalassaemia is a compound heterozygous mutation with a vast clinical phenotype [1]. To improve quality of life, HbE/β-thalassaemia individuals receive different treatment strategies, either individually or in combination with therapy(ies), including blood transfusion, iron chelation and splenectomy [2-3]. Thus far, there are limited studies conducted regarding the effect of treatments in HbE/β-thalassaemia individuals. We hereby investigated the effect of treatments with respect to red blood cell indices, haemoglobin subtypes and gene expressions among 30 HbE/beta-thalassaemia individuals. Statistical analyses were carried out using SPSS 17.0. As compared to single therapy (transfused only individuals) and double therapies (transfused-chelated only individuals), individuals receiving triple therapies (transfused-chelated-splenectomised individuals) showed significantly high mean cell volume (MCV), mean cell haemoglobin (MCH) and reticulocytes count (Fig.1).
These findings suggest that triple therapies are the most effective in ameliorating the severity of the disease in terms of microcytosis and hypochromia [3-5]. The high reticulocyte count in triple therapies also allows the bone marrow to actively produce red blood cells suggesting that these therapies have clinical benefits by suppressing the ineffective erythropoiesis and improving the erythropoietic environment significantly among HbE/β-thalassaemia individuals in our studied group [6-7].
The effectiveness of these treatments is different among each HbE/β-thalassaemia individual whereby clinical variabilities among them could be a contributing factor. Triple therapies giving the best advantage to the HbE/β-thalassaemia patient in this study.
It is important to study optimism as it is negatively correlated with anxiety and depressive and positively correlated with quality of life in cancer patients. This study translated and investigated the psychometric properties of the Malay version of the Life Orientation Test-Revised (LOT-R) among Malaysian cancer patients. The validated Malay version of the LOT-R will be used for assessing level of optimism among Malaysian cancer patients in future studies and determine factors associated with it in order to design effective psychosocial intervention which will enhance level of optimism in cancer patients. Concurrent translation and back translation of original English version of the LOT-R to Malay was performed and the Malay version was administered to 195 cancer patients of different cancer diagnoses at baseline assessment and repeated 2 months later at follow up. Reliability was assessed with internal consistency (Cronbach’s α) and test-retest reliability (intraclass correlation coefficient), validity was assessed with face, content, convergent, and discriminant validities. Construct validity was examined with exploratory factor analysis. Two third of the participants (n = 129/195; 66%) were of middle age, three forth were females (n = 142/195; 72.8%) and eight tenth were Malays (n = 160/195; 82.1%). The LOT-R (Malay) total score (Cronbach’s α = 0.58; ICC = 0.62) and its domains (Cronbach’s α [Optimism) = 0.60; Cronbach’s α[Pessimism) = 0.42; ICC[Optimism] = 0.61; ICC[Pessimism] = 0.59) demonstrated questionable internal consistencies but acceptable test-retest reliability. Convergent and discriminant validities were achieved by the LOT-R (Malay). Construct validity was also demonstrated by the LOT-R (Malay) as exploratory factor analysis showed that all the items had factor loadings > 0.4.
The LOT-R (Malay) has acceptable psychometric properties and suitable to assess optimism in Malaysian cancer patients. It should be validated for use in other Malaysian populations.
Globally, α-thalassaemia is a highly prevalent disease. In Malaysia, this disorder is a well-known public health problem [1]. The three most common deletional α-thalassaemia found in this region include --SEA deletion, -α3.7 and -α4.2 deletions [2]. The prevalence rate of triplication alpha cases such as αααanti3.7 and αααanti4.2 is unknown in Malaysia although it plays a pivotal role in exacerbating the clinical phenotypes in beta thalassaemia carriers [3]. Therefore, the purpose of this study was to design an assay for the detection of triplications and common deletional alpha thalassaemia using droplet digital PCR (ddPCR). Copy number changes were analysed using Quanta-SoftTM software version 1.6.6 after performing ddPCR. Sensitivity and validation analysis were also performed on the DNA samples. The changes in copy number changes (common deletions, duplications and triplications) in the alpha globin gene has been quantitatively detected using ddPCR. For the samples validation as determined by ddPCR, the mean copy number values for αα/αα are 2.0275±0.0177 (HS-40), 1.8175±0.0389 (HBA2), 2.0450±0.0848 (HB 3.7), 2.0050±0.0000 (HBA1). For -α3.7 /--SEA, the mean copy number values are 2.0225±0.2180 (HS-40), 0.9325±0.1213 (HBA2), 0 (HB 3.7), 0.9984±0.1333 (HBA1). As for –α4.2 /--SEA, the mean copy number values are 1.9350 (HS-40), 0 (HBA2), 0.7945 (HB 3.7), 0.8480 (HBA1). The mean copy number values for --SEA/αα samples are 1.9067±0.1327 (HS-40), 0.8164±0.0364 (HBA2), 0.8920±0.0434 (HB 3.7), 0.9148±0.0338 (HBA1) respectively. This study has found that the use of ddPCR is convenient as it allows direct quantification without the requirement of a calibration curve unlike qPCR [4]. Secondly, this study also showed that ddPCR is accurate and precise in the detection of alpha thalassaemia deletions and triplications based on the gene dosages using absolute quantification. In addition, the non-requirement of post-PCR work has minimised the risk of PCR carryover contamination. Thirdly, ddPCR saves time with less turnaround time and minimise the labour work required as compared to techniques such as MLPA which requires DNA denaturation and hybridisation reaction on day 1 while ligation and PCR reaction on day 2. Fourthly, this study found that the detection of α-thalassaemia using ddPCR is sensitive. DNA samples with low concentration as low as 1 ng were able to be detected for α-thalassaemia using ddPCR. The ability to detect minute amount of DNA concentration is crucial particularly in the diagnosing of the lethal HbH hydrops foetalis during the neonatal stage in α-thalassaemia. In conclusion, this is an alternative method (ddPCR) that can be employed for rapid detection of alpha thalassaemia variants in Malaysia.