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Fractal analysis approach in the characterisation of cerebrovascular complexity in asymptomatic cerebral small vessel disease
(2023-02)
Aminuddin, Niferiti
Cerebral small vessel disease (CSVD) refers to a spectrum of clinical and neuroimaging findings caused by pathological damage of small vessels of the cerebral parenchyma. Cerebral white matter hyperintensity (WMH) is one of the commonest neuroimaging findings of CSVD. Often, CSVD is diagnosed once the symptoms developed. Detection of the underlying vascular structural changes might facilitate early disease risk stratification and disease monitoring as vascular alteration precedes cerebral parenchymal injury. Of interest, fractal analysis allows us to quantitatively measure the complexity of the cerebral vascular structure in terms of fractal dimension (Df). The cerebral vascular Df changes are indicative of inefficient tissues perfusion which renders the cerebral parenchyma vulnerable to damage. The aim of this study is to explore a novel vascular neuroimaging marker of asymptomatic CSVD by characterising the complexity of the circle of Willis (CoW) and its tributaries as measured by Df. An exploratory cross-sectional study was conducted involving 22 subjects of age between 25 - 75 years old with low to moderate QRISK2 score who underwent magnetic resonance imaging/angiography (MRI/MRA) examination. These subjects presented with or without WMH. The cerebral vascular complexity of the MRA image was characterised using Df. The cerebral vascular Df was compared between asymptomatic subjects with (WMH+; n = 8) and without cerebral WMH (WMH-; n = 14). Furthermore, cerebral vascular Df was also compared between asymptomatic subjects with both CSVD risk factors and cerebral WMH (RF+ & WMH+; n = 6), subjects with CSVD risk factors only (RF+ & WMH-; n = 5), and subjects without both CSVD risk factors and cerebral WMH (RF- & WMH-; n = 9). Simple linear regression (SLR) was performed between QRISK2 score and cerebral vascular Df. Mean cerebral vascular Df was significantly lower in the WMH+ group than WMH- group. Moreover, the mean cerebral vascular Df of the RF+ & WMH- and RF+ & WMH+ groups were significantly lower than RF- & WMH- group. The SLR model had indicated that increased QRISK2 score significantly predicted reduction in cerebral vascular Df. The cerebral vascular Df was reduced in the subjects with CSVD risk factors and asymptomatic CSVD subjects with WMH. The SLR model had indicated that QRISK2 score significantly predicted cerebral vascular Df. The results indicate that cerebral vascular Df is a promising biomarker of asymptomatic CSVD subjects with WMH. Larger-scaled studies are required to explore its potential in a broader population setting.
Development and validation of the measurement tools and health education module on knowledge and practices for dengue among kindergarten children in Kelantan
(2023-03)
Subramaniam, Neevaarthana
Dengue had been classified as one of the longest existing vector-borne diseases in Malaysia. Community members of all age groups had been prone to dengue infection, however, awareness related studies on dengue among kindergarten children aged five to six years had not been widely explored. Hence, this study aims to assess knowledge and practice levels and test the educational intervention programmes for young children in urban, sub-urban and rural areas of Kelantan. To achieve the objective, this study consisted of a cross-sectional and interventional study design which was conducted in four different phases. In Phase I, a guided interview-based questionnaire with 40 initial items to measure knowledge and practice levels was developed. Flashcards representing the illustration for selected items were also developed. The interview-based questionnaire was then validated and revised through content validity and face validity. The revised interview-based questionnaire was proceeded for item, factor and reliability analysis. The finalised interview-based questionnaire was then pre-tested following a cross-sectional study design among randomly selected 200 kindergarten children. In Phase II, a total of 396 kindergarten children were recruited to obtain knowledge and practice levels using the pre-validated interview-based questionnaire. Next, in Phase III, activity-based and module-based intervention programmes were developed, validated by experts and revised accordingly. In Phase IV, the revised activity and module intervention programmes were proceeded to be tested among 46 and 72 kindergarten children, respectively. Data from all the phases were analysed using the Statistical Package of the Social Sciences (SPSS) according to the respective tests needed to produce the results. For the outcome of this study, the final version of questionnaire consisted of 33 items, with a good internal consistency of Cronbach Alpha of 0.788. Through the measurement of knowledge and practice, practice levels were seen to be significantly higher in both urban and sub-urban areas compared to the rural area (p < 0.05). Significant differences (p < 0.001) were observed in both knowledge and practice scores among participants after implementation of educational intervention programmes. Therefore, this study concludes that the approach using the interview-based questionnaire and the specifically designed educational intervention programmes are effective. They can be considered valid and reliable study instruments for early exposure of dengue knowledge and practices among kindergarten children aged five to six years old.
Removal of arsenic from aqueous solution by various natural soil-based adsorbents
(2023-03)
Fairuz, Farah Shahirah Mohd
Rapid industrialization, mining and agricultural activities lead to the release of contaminants such as arsenic (As) into the water sources that causes adverse effect to living organism. Thus, the application of effective and efficient removal method is crucial. The objective of the study is to apply the adsorption method by utilizing natural soil-based adsorbents including red, clay, sandy and black soil for removal of arsenic from aqueous solution. This study involved the characterisation of heavy metal content and physicochemical characteristic of soil adsorbents, followed by batch adsorption process and the study of adsorption model and mechanism. The results for concentration of arsenic in all soil adsorbents were lower than the permissible limit stated by European United (EU) and mean concentration of iron (Fe) observed to be higher in red soil compared to in other soil samples. For the physicochemical characterisation analysis, red soil has highest number of functional group, content of Fe based minerals, surface area and pore volume with the smallest particle size. From this study, the optimum removal conditions of arsenic from aqueous solution were 2.2 g/50 mL dosage of adsorbents for 60 minutes of contact time at pH of 5.5±0.5 and temperature of 40°C. The adsorption capability and efficiency of soil adsorbent in removing arsenic from aqueous solution were red soil> clay soil> sandy soil> black soil. The kinetic, isotherm and thermodynamic model showed that the mechanism of adsorption of arsenic was a chemisorption, non-spontaneous and endothermic process.
Molecular characterisation of alpha-thalassaemia in patients investigated for hypochromic microcytic indices in Hospital Universiti Sains Malaysia
(2023-03)
Vijian, Divashini
Alpha (α)-thalassaemia is a common genetic disorder that affects 5 % of the worldwide population. Deletional or non-deletional mutations of one or both HBA1 and HBA2 on chromosome 16 cause a reduction/abnormal in the production of α globin chains, a component of haemoglobin (Hb) which are required for the formation of red blood cells (RBC). Thus, reduced Hb leads to anaemia. Many genetic mutations in α- thalassaemia have been discovered, which produced wide spectrum of clinical manifestation, ranging from asymptomatic to lethal. This study focused on the characterisation of RBC parameters and molecular based on α-thalassaemia mutations to determine the prevalence and to describe the RBC parameters based on the mutations detected. A cross-sectional study involving 136 suspected α-thalassaemia patients was collected. The DNA extracted from blood samples was subjected to the multiplex GAP-polymerase chain reaction, multiplex amplification refractory mutation system polymerase chain reaction (MARMS-PCR), and duplex-polymerase chain reaction to detect common deletional and non-deletional α mutations, respectively. Multiplex ligation dependent probe amplification and Sanger sequencing were performed to detect rare mutations in patients that do not carry any common mutations. The prevalence of α-thalassaemia in this study was 47.1 %. Thirty-nine and 1.4 percent of patients were found to have heterozygous and homozygous α- thalassaemia mutations, respectively, with 6.6 percent being compound heterozygous. Among the patients, the following genotypes were found: -α3.7/αα (15.4 %), -α4.2/αα (3.7 %), --SEA/αα (7.4 %), αCSα/αα (10.3 %), αAdanaα/αα (0.7 %), αQuong Szeα/αα (1.5 %), -α3.7/-α3.7 (0.7 %), αCSα/αCSα (0.7 %), -α4.2/αCSα (0.7 %), –SEA/αCSα (1.5 %), –SEA/αQuong Szeα (0.7 %), -α3.7/αAdanaα (0.7 %), --SEA/-α3.7 (2.2 %) and αCSα/αAdanaα (0.7 %). Statistical analysis of RBC parameters according to the mutations was performed. A few indicators, such as Hb (p=0.020), mean corpuscular volume (p=0.008), mean corpuscular haemoglobin (p=0.018), RBC (p=0.029) and haematocrit (p=0.049), showed significant changes among patients with deletional mutations, but there were no significant differences between patients with non-deletional mutations. patients with single gene deletional and non-deletional mutations shows only significant differences for HbA2 (p=0.028). A wide range of RBC parameters were observed among the patients, including those with the same genotypes. Thus, based on RBC parameters alone, they are not sufficient to describe the specific mutations of α- thalassaemia.
The cytotoxicity and antimicrobial activity of andrographis paniculata herbal mouthwash formulation
(2023-02)
Alojid, Anis Amiera Muhamad
Oral disease is a global health problem caused by oral pathogens. To prevent the oral disease, mouthwash is commonly used. However, commercial mouthwash contained alcohol and other chemicals found to be toxic with unfavourable side effects. Besides, existence drugs seemed to be ineffective due to excessive use and multidrug resistance against the oral pathogens. Thus, there is a demand for a safer and effective alternative treatment in dental product. As the studies on cytotoxicity and antimicrobial activities of medicinal herb, Andrographis paniculata (AP) against oral pathogens are limited, this study proposed AP aqueous extract as herbal mouthwash to determine its effectiveness against selected oral pathogens; Porphyromonas gingivalis, Streptococcus mutans, S. sobrinus, Staphylococcus aureus, and Actinomyces viscosus. In this study, antibacterial effect of AP aqueous extract against the tested oral pathogens was determined by disc diffusion and well diffusion assays, followed by antibacterial effect of five concentrations of AP herbal mouthwash at 1000, 500, 250, 125 and 62.5 mg/mL using well diffusion and broth microdilution method. Assessment of toxicity was determined by brine shrimp lethality bioassay and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay onto L929 fibroblast cells while the analysis of heavy metal was analysed using atomic absorption spectrometry (AAS). Stability study was carried out on the final product of AP herbal mouthwash. Results revealed that AP aqueous extract significantly inhibited the growth of all oral pathogens (p<0.05) except for S. aureus with inhibition zones ranging from 2.83 ± 0.83 mm to 14.37 ± 0.83.mm. Similar to AP aqueous extract, AP herbal mouthwash exhibited significant antibacterial activities onto all tested pathogens except for S. aureus (p<0.05) with inhibition ranging from median (IQR) of 9.50 (3.80) to median (IQR) of 15.00 (3.40). All mouthwash concentrations caused bacteria inhibition from 10.56% to 261.09% with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) at 3.90 mg/mL to 7.81 mg/mL and 7.81 mg/mL to 62.50 mg/mL respectively. However, there was no MBC detected for S. aureus at these concentrations. Formulation of mouthwash was non-toxic to brine shrimp and L929 fibroblast cell line with LC50 value 3255.06 μg/mL and IC50 value 43.55 mg/mL respectively. AP herbal mouthwash was free from heavy metal contamination and maintained its characteristics and sterility for 12 months storage. In conclusion, AP herbal mouthwash at 7.81 mg/mL was found to be the best mouthwash formulation. However, more research works need to be carried out for its clinical use for further product commercialization.