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Enhanced sensing of dengue virus DNA detection using O2 plasma treated-silicon nanowire based electrical biosensor

Rahman SF, Yusof NA, Hashim U, Hushiarian R, M N MN, Hamidon MN, et al.

Anal Chim Acta, 2016 Oct 26;942:74-85.
PMID: 27720124 DOI: 10.1016/j.aca.2016.09.009

Dengue Virus (DENV) has become one of the most serious arthropod-borne viral diseases, causing death globally. The existing methods for DENV detection suffer from the late stage treatment due to antibodies-based detection which is feasible only after five days following the onset of the illness. Here, we demonstrated the highly effective molecular electronic based detection utilizing silicon nanowire (SiNW) integrated with standard complementary metal-oxide-semiconductor (CMOS) process as a sensing device for detecting deoxyribonucleic acid (DNA) related to DENV in an early stage diagnosis. To transform the fabricated devices as a functional sensing element, three-step procedure consist of SiNW surface modification, DNA immobilization and DNA hybridization were employed. The detection principle works by detecting the changes in current of SiNW which bridge the source and drain terminal to sense the immobilization of probe DNA and their hybridization with target DNA. The oxygen (O2) plasma was proposed as an effective strategy for increasing the binding amounts of target DNA by modified the SiNW surface. It was found that the detection limit of the optimized O2 plasma treated-SiNW device could be reduced to 1.985 × 10-14 M with a linear detection range of the sequence-specific DNA from 1.0 × 10-9 M to 1.0 × 10-13 M. In addition, the developed biosensor device was able to discriminate between complementary, single mismatch and non-complementary DNA sequences. This highly sensitive assay was then applied to the detection of reverse transcription-polymerase chain reaction (RT-PCR) product of DENV-DNA, making it as a potential method for disease diagnosis through electrical biosensor.
Immunophenotyping analysis of lymph node biopsies by flow cytometry

Raja-Sabudin RZ, Hamid AA, Yusof N, Alauddin H, Aziz SA, Kulaveerasingam S, et al.

Saudi Med J, 2012 Oct;33(10):1131-3.
PMID: 23047221
A retrospective study on annual evaluation of radiation processing for frozen bone allografts complying to quality system requirements

Ramalingam S, Mohd S, Samsuddin SM, Min NG, Yusof N, Mansor A

Cell Tissue Bank, 2015 Dec;16(4):545-52.
PMID: 25687771 DOI: 10.1007/s10561-015-9501-1

Bone allografts have been used widely to fill up essential void in orthopaedic surgeries. The benefit of using allografts to replace and reconstruct musculoskeletal injuries, fractures or disease has obtained overwhelming acceptance from orthopaedic surgeons worldwide. However, bacterial infection and disease transmission through bone allograft transplantation have always been a significant issue. Sterilization by radiation is an effective method to eliminate unwanted microorganisms thus assist in preventing life threatening allograft associated infections. Femoral heads procured from living donors and long bones (femur and tibia) procured from cadaveric donors were sterilized at 25 kGy in compliance with international standard ISO 11137. According to quality requirements, all records of bone banking were evaluated annually. This retrospective study was carried out on annual evaluation of radiation records from 1998 until 2012. The minimum doses absorbed by the bones were ranging from 25.3 to 38.2 kGy while the absorbed maximum doses were from 25.4 to 42.3 kGy. All the bones supplied by our UMMC Bone Bank were sterile at the required minimum dose of 25 kGy. Our analysis on dose variation showed that the dose uniformity ratios in 37 irradiated boxes of 31 radiation batches were in the range of 1.003-1.251, which indicated the doses were well distributed.
Performance of cooling materials and their composites in maintaining freezing temperature during irradiation and transportation of bone allografts

Ramalingam S, Samsuddin SM, Yusof N, Mohd S, Hanafi NN, Min NW, et al.

J Orthop Surg (Hong Kong), 2018 4 27;26(2):2309499018770906.
PMID: 29695196 DOI: 10.1177/2309499018770906

PURPOSE: Bone allografts supplied by University Malaya Medical Centre Bone Bank are sterilized by gamma radiation at 25 kGy in dry ice (DI) to minimize radiation effects. Use of cheaper and easily available cooling materials, gel ice (GI) and ice pack (IP), was explored. Composites of DI and GI were also studied for the use in routine transportations and radiation process.
METHODS: (a) Five dummy bones were packed with DI, GI, or IP in a polystyrene box. The bone temperatures were monitored while the boxes were placed at room temperature over 96 h. Durations for each cooling material maintaining freezing temperatures below -40°C, -20°C, and 0°C were obtained from the bone temperature over time profiles. (b) Composites of DI (20, 15, 10, 5, and 0 kg) and GI were used to pack five dummy bones in a polystyrene box. The durations maintaining varying levels of freezing temperature were compared.
RESULTS: DI (20 kg) maintained temperature below -40°C for 76.4 h as compared to 6.3 h in GI (20 bags) and 4.0 h in IP (15 packs). Composites of 15DI (15 kg DI and 9 GI bags) and 10DI (10 kg DI and 17 GI bags) maintained the temperature below -40°C for 61 and 35.5 h, respectively.
CONCLUSION: Composites of DI and GI can be used to maintain bones in deep frozen state during irradiation, thus avoiding radiation effects on biomechanical properties. Sterile frozen bone allograft with preserved functional properties is required in clinical applications.
Fulltext Enzymatic and genetic characterization of lignin depolymerization by Streptomyces sp. S6 isolated from a tropical environment

Riyadi FA, Tahir AA, Yusof N, Sabri NSA, Noor MJMM, Akhir FNMD, et al.

Sci Rep, 2020 05 08;10(1):7813.
PMID: 32385385 DOI: 10.1038/s41598-020-64817-4

The conversion of lignocellulosic biomass into bioethanol or biochemical products requires a crucial pretreatment process to breakdown the recalcitrant lignin structure. This research focuses on the isolation and characterization of a lignin-degrading bacterial strain from a decaying oil palm empty fruit bunch (OPEFB). The isolated strain, identified as Streptomyces sp. S6, grew in a minimal medium with Kraft lignin (KL) as the sole carbon source. Several known ligninolytic enzyme assays were performed, and lignin peroxidase (LiP), laccase (Lac), dye-decolorizing peroxidase (DyP) and aryl-alcohol oxidase (AAO) activities were detected. A 55.3% reduction in the molecular weight (Mw) of KL was observed after 7 days of incubation with Streptomyces sp. S6 based on gel-permeation chromatography (GPC). Gas chromatography-mass spectrometry (GC-MS) also successfully highlighted the production of lignin-derived aromatic compounds, such as 3-methyl-butanoic acid, guaiacol derivatives, and 4,6-dimethyl-dodecane, after treatment of KL with strain S6. Finally, draft genome analysis of Streptomyces sp. S6 also revealed the presence of strong lignin degradation machinery and identified various candidate genes responsible for lignin depolymerization, as well as for the mineralization of the lower molecular weight compounds, confirming the lignin degradation capability of the bacterial strain.
Virtual counselling of tobacco cessation during the COVID-19 pandemic: A qualitative study on the experiences and perceptions of Malaysian dental undergraduates and their patients

Roslan N, Yusof N, Md Bohari NF, Md Sabri BA, Mohd Radzi NA, Bakri NN, et al.

Eur J Dent Educ, 2024 Feb;28(1):28-40.
PMID: 37132218 DOI: 10.1111/eje.12912

INTRODUCTION: When dental institutions had to close down during the Movement Control Order (MCO) implementation due to the COVID-19 pandemic, dental students were faced with delays in completing their tobacco cessation schedule. An alternative was to allow students to conduct virtual counselling (VC) for smoking cessation for their patients to address their clinical requirements. This study aimed to explore Malaysian dental undergraduates' and patients' experiences undergoing smoking cessation counselling through virtual platforms.
MATERIALS AND METHODS: The study consisted of qualitative, semi-structured Focus Group Discussions (for students, n = 23) and in-depth interviews (for patients, n = 9); to phenomenologically describe the perceptions of participants involved in the VC. Each session was recorded with the participants' permission. The recorded session was transcribed verbatim and thematically analysed using the qualitative data analysis software, NVivo™.
RESULTS: The major themes that emerged were: (1) General opinions and experiences, (2) Content of VCs, (3) Remote access to counselling, (4) Patient-clinician relationships, (5) Technical issues, (6) Changes after VCs, and (7) Future application. Most students and patients were quite comfortable with VC as it is convenient, allowing students to be creative and avoid the hassle of transport and traffic. However, some of the students felt that it lacked the personal touch and guidance from lecturers who would normally be present during physical class.
CONCLUSION: Virtual counselling enables remote access to counselling, but it is also subjected to some limitations, especially regarding lack of clinical assessments, human touch and internet issues. Though participants were optimistic about adapting it in the future, multiple factors must be considered. Ultimately, the behavioural change will depend on the patient's motivation in making a difference.
Fulltext Secondary Sea-Blue Histiocytosis in a Patient with Transfusion Dependent HbE-Beta Thalassaemia and Osteosarcoma

Saad Eldeen Bakheet O, Yusof N, Raja Zahratul A, Ithnin A, Abdul Aziz S, Alias H

Indian J Hematol Blood Transfus, 2016 Jun;32(Suppl 1):262-6.
PMID: 27408409 DOI: 10.1007/s12288-015-0582-6

Secondary sea-blue histiocytosis occurs more frequently than the primary form and occurs consequent to a wide range of metabolic and haematologic disorders including thalassaemia. We report an 18-year-old Chinese boy with transfusion-dependent HbE-beta thalassaemia who complained of pain and swelling at the left iliac crest region for 2 months duration. Physical examination revealed pallor with hepatosplenomegaly. Local examination revealed a huge swelling 12 cm × 12 cm in diameter, firm in consistency and tender. Histopathological examination of the mass revealed an osteosarcoma. His bone marrow aspirate showed numerous sea-blue histiocytes, the cytoplasm of which was closely packed with fine granules that stained blue with May-Grunwald-Giemsa. The nuclei were centrally located in some cells and displaced towards the periphery in other cells. There was no malignant cell infiltration in the marrow. The case is reported due to the co-incidental dual pathology in our patient (HbE-beta thalassaemia and osteosarcoma) and the unusual bone marrow finding of numerous sea-blue histiocytes.
Fulltext Mutations of pvdhfr and pvdhps genes in vivax endemic-malaria areas in Kota Marudu and Kalabakan, Sabah

Sastu UR, Abdullah NR, Norahmad NA, Saat MN, Muniandy PK, Jelip J, et al.

Malar J, 2016;15:63.
PMID: 26850038 DOI: 10.1186/s12936-016-1109-9

Malaria cases persist in some remote areas in Sabah and Sarawak despite the ongoing and largely successful malaria control programme conducted by the Vector Borne Disease Control Programme, Ministry Of Health, Malaysia. Point mutations in the genes that encode the two enzymes involved in the folate biosynthesis pathway, dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) enzymes confer resistance to pyrimethamine and sulfadoxine respectively, in both Plasmodium falciparum and P. vivax. The aim of the current study was to determine the mutation on both pvdhfr at codon 13, 33, 57, 58, 61, 117, and 173 and pvdhps genes at codon 383 and 553, which are potentially associated with resistance to pyrimethamine and sulfadoxine in P. vivax samples in Sabah.
Fulltext Microbiological and physical properties of pennywort (Centella asiatica) leaves using pulsed light technology

Siti Zaharah, R., Noranizan, M., Son, R., Roselina, K., Yusof, N. L., Koh, P. C., et al.

International Food Research Journal, 2020;27(1):16-27.
MyJurnal

Pennywort (Centella asiatica) is a herbaceous vegetable commonly consumed raw as ‘ulam’ or salad. Consumption of raw leafy green vegetables is one of the pathogenic mechanisms that could cause foodborne outbreaks. The aim of the present work was therefore to investigate the effect of pulsed light (PL) treatment at fluences of 1.5, 4.2, 6.9, 9.6, and 12.3 J/cm² on the microbiological and physical quality of pennywort stored at 4 ± 1°C. Escherichia coli (E. coli) were inoculated onto the pennywort leaves before being exposed to PL and viewed using scanning electron microscopy (SEM). PL fluences of 6.9, 9.6, and 12.3 J/cm² significantly reduced the microbial count; however, the highest inactivation was obtained by using fluences of 9.6 and 12.3 J/cm². The color of pennywort was not significantly affected by PL treatment applied at lower fluences of 1.5, 4.2, and 6.9 J/cm²; however, at higher fluence, 9.6 and 12.3 J/cm², the color was affected. PL at 1.5, 4.2, 6.9, and 9.6 J/cm² was able to retain the texture appearance of the leaves. To conclude, PL at 6.9 J/cm² showed the best fluence to reduce total aerobic mesophilic count while retaining the physical properties of pennywort leaves and extend the shelf life to about four days. The inactivation of E. coli population was significantly higher at PL fluence of 6.9 J/cm². It was observed that PL caused the destruction to the surface of E. coli’s cell membrane. The reductions of samples inoculated with E. coli were better than those achieved in native microbiota. Furthermore, the present work also demonstrated that PL treatment was able to reduce the microbial count on pennywort leaves.
Fulltext Microbial Diversity in Decaying Oil Palm Empty Fruit Bunches (OPEFB) and Isolation of Lignin-degrading Bacteria from a Tropical Environment

Tahir AA, Mohd Barnoh NF, Yusof N, Mohd Said NN, Utsumi M, Yen AM, et al.

Microbes Environ, 2019 Jun 27;34(2):161-168.
PMID: 31019143 DOI: 10.1264/jsme2.ME18117

Oil palm empty fruit bunches (OPEFB) are the most abundant, inexpensive, and environmentally friendly lignocellulosic biomass in Malaysia. Investigations on the microbial diversity of decaying OPEFB may reveal microbes with complex enzymes that have the potential to enhance the conversion of lignocellulose into second-generation biofuels as well as the production of other value-added products. In the present study, fungal and bacterial diversities in decaying OPEFB were identified using Illumina MiSeq sequencing of the V3 region of the 16S rRNA gene and V4 region of the 18S rRNA gene. Fungal diversity in decaying OPEFB was dominated by the phylum Ascomycota (14.43%), while most of the bacterial sequences retrieved belonged to Proteobacteria (76.71%). Three bacterial strains isolated from decaying OPEFB, designated as S18, S20, and S36, appeared to grow with extracted OPEFB-lignin and Kraft lignin (KL) as the sole carbon source. 16S rRNA gene sequencing identified the 3 isolates as Paenibacillus sp.. The molecular weight distribution of KL before and after degradation showed significant depolymerization when treated with bacterial strains S18, S20, and S36. The presence of low-molecular-weight lignin-related compounds, such as vanillin and 2-methoxyphenol derivatives, which were detected by a GC-MS analysis, confirmed the KL-degrading activities of isolated Paenibacillus strains.
Fulltext Retrospective study on the microbial drug resistance profile and predictive risk factors in early infection of open fractures.

Tai KM, Sulong AF, Mohd. Yusof N

IIUM Medical Journal Malaysia, 2019;18(3):96-103.
MyJurnal

This study was conducted to evaluate the susceptibility of microorganisms involved in early infection of open fractures in orthopaedics to current prophylactic antibiotics practice and determine the association of various parameters related to the causative organism, patient, injury and management to the resistance of such microorganisms. Methods: This is a retrospective study that reviewed cases collected from the surgical operations record from January 2015 to December 2017 in Hospital Tengku Ampuan Afzan, Kuantan. A total of 179 cases were collected with 110 cases fulfilling the proposed inclusion / exclusion criteria. They all underwent routine debridement followed by culture and sensitivity. Previous clinical records were traced to identify the various risk factors for infection and evaluate these against the resistance of the microorganisms to prophylactic antimicrobial drugs. Results: Admission to the intensive care unit, blood transfusion, antibiotic regime and duration, fracture grade, injury severity score and duration of admission were all significantly associated with resistance of microorganism. The study also demonstrated the predominance of Gram-negative microorganisms constituting 65.9% of isolates. Gram-negative microorganisms were seen more in higher fracture grades and Injury Severity Scale, and longer duration of admission and antibiotic treatment. The overall susceptibility of microorganisms to antibiotics was also demonstrated with up to 68.6% resistance to cefuroxime and 36.9% to Gentamicin. Staphylococcus aureus and MRSA were the commonest Gram-positive organisms while Pseudomonas and Acinetobacter spp. the commonest Gram-negatives. Conclusion: Admission to Intensive Care Unit, blood transfusion, antibiotic regime and duration, fracture grade, injury severity score and duration of antibiotics have a significant positive predictive value to the development of resistance of microorganisms. The shift to predominantly Gram-negative microorganisms indicate an urgency to modify management of open fracture to achieve optimal results. This will also prevent the emergence of new multi-drug resistance microorganism which is already a worldwide public health problem.
Fulltext Development of Copper-Aluminum Layered Double Hydroxide in Thin Film Nanocomposite Nanofiltration Membrane for Water Purification Process

Tajuddin MH, Yusof N, Wan Azelee I, Wan Salleh WN, Ismail AF, Jaafar J, et al.

Front Chem, 2019;7:3.
PMID: 30800647 DOI: 10.3389/fchem.2019.00003

This study aims to fabricate a thin film composite (TFC) membrane, modified with copper-aluminium layered double hydroxide (LDH) nanofillers via interfacial polymerization technique for nanofiltration (NF) processes. It was found that Cu-Al LDH nanofillers possessed layered structured materials with typical hexagonal plate-like shape and positive surface charge. The study revealed that TFN membrane exhibits a relatively smooth surface and a less nodular structure compared to pristine TFC membrane. The contact angle of TFN progressively decreased from 54.1° to 37.25°, indicating enhancement in surface hydrophilicity. Moreover, the incorporation of LDH nanofillers resulted in a less negative membrane as compared to the pristine TFC membrane. The best NF performance was achieved by TFN2 membrane with 0.1° of Cu-Al LDH loading and a water flux of 7.01 Lm-2h-1.bar. The addition of Cu-Al LDH resulted in excellent single salt rejections of Na2SO4 (96.8%), MgCl2 (95.6%), MgSO4 (95.4%), and NaCl (60.8%). The improvement in anti-fouling properties of resultant TFN membranes can be observed from the increments of pure water flux recovery and normalized water flux by 14% and 25% respectively. The findings indicated that Cu-Al LDH is a promising material in tailoring membrane surface properties and fouling resistance. The modification of the LDH-filled TFN membrane shows another alternative to fabricating a high-performance composite membrane, especially for water softening and partial desalination process.
Does bone marrow aspirate help enhance the integration of gamma irradiated allograft bone?

Thong FY, Mansor A, Ramalingam S, Yusof N

Cell Tissue Bank, 2020 Mar;21(1):107-117.
PMID: 31894432 DOI: 10.1007/s10561-019-09804-4

Bone allografts donated by other individuals offer a viable alternative to autograft. Risks of disease transmission are overcome by sterilizing the bone; unfortunately sterilization methods generally affect bone functional properties including osteogenic potential and biomechanical integrity. This study aimed to determine any enhancement effect when gamma sterilised allografts was impregnated with autologous bone marrow in improving the rate and quality of integration in metaphyseal-tibial defects of rabbits. Almost all subjects showed 50% of the defect being covered by new bones by the third week and smaller residual defect size in the treated group at the fifth week. Hounsfield units at the defect site showed increasing healing in all samples, with the treated group having an apparent advantage although insignificant (p > 0.05). In the histopathological score evaluating healing over cortical and cancellous bone at the fracture site showed only slight variations between the groups (p > 0.05). Therefore no enhanced healing by the autologous bone marrow was observed when added to the bone allografts in treating the unicortical defects.
Bio-cellulose Production by Beijerinckia fluminensis WAUPM53 and Gluconacetobacter xylinus 0416 in Sago By-product Medium

Voon WWY, Muhialdin BJ, Yusof NL, Rukayadi Y, Meor Hussin AS

Appl Biochem Biotechnol, 2019 Jan;187(1):211-220.
PMID: 29915916 DOI: 10.1007/s12010-018-2807-2

Bio-cellulose is the microbial extracellular cellulose that is produced by growing several microorganisms on agriculture by-products, and it is used in several food applications. This study aims to utilize sago by-product, coconut water, and the standard medium Hestrin-Schramm as the carbon sources in the culture medium for bio-cellulose production. The bacteria Beijerinkia fluminensis WAUPM53 and Gluconacetobacter xylinus 0416 were selected based on their bio-cellulose production activity. The structure was determined by Fourier transform infrared spectroscopy and scanning electron microscopy, while the toxicity safety was evaluated by brine shrimp lethality test. The results of Fourier transform infrared spectroscopy showed that the bio-cellulose produced by B. fluminensis cultivated in sago by-products was of high quality. The bio-cellulose production by B. fluminensis in the sago by-product medium was slightly higher than that in the coconut water medium and was comparable with the production in the Hestrin-Schramm medium. Brine shrimp lethality test confirmed that the bio-cellulose produced by B. fluminensis in the sago by-product medium has no toxicity, which is safe for applications in the food industry. This is the first study to determine the high potential of sago by-product to be used as a new carbon source for the bio-cellulose production.
Superwetting materials for hydrophilic-oleophobic membrane in oily wastewater treatment

Wan Ikhsan SN, Yusof N, Aziz F, Ismail AF, Jaafar J, Wan Salleh WN, et al.

J Environ Manage, 2021 Jul 15;290:112565.
PMID: 33873023 DOI: 10.1016/j.jenvman.2021.112565

The vast amount of oily wastewater released to the environment through industrialization has worsened the water quality in recent years, posing adverse impacts on general human health. Oil emulsified in water is one of the most difficult mixtures to be treated, making it imperative for new technology to be explored to address this issue. The use of conventional water treatment such as flotation, coagulation, precipitation, adsorption, and chemical treatment have low separation efficiencies and high energy costs, and are not applicable to the separation of oil/water emulsions. Therefore, there is a demand for more efficient methods and materials for the separations of immiscible oil/water mixtures and emulsions. Superwetting materials that can repel oil, while letting water pass through have been widely explored to fit into this concern. These materials usually make use of simultaneous hydrophilic/oleophobic mechanisms to allow a solid surface to separate oily emulsion with little to no use of energy. Also, by integrating specific wettability concepts with appropriate pore scale, solid surfaces may achieve separation of multifarious oil/water mixtures namely immiscible oil/water blends and consolidated emulsions. In this review, materials used to impart superwetting in solid surfaces by focusing on superhydrophilic/superoleophobic wetting properties of the materials categorized into fluorinated and non-fluorinated surface modification are summarized. In each material, its background, mechanism, fabricating processes, and their effects on solid surface's wetting capability are elaborated in detail. The materials reviewed in this paper are mainly organic and green, suggesting the alternative material to replace the fluorine group that is widely used to achieve oleophobicity in oily wastewater treatment.
Fulltext Halloysite Nanotube-Ferrihydrite Incorporated Polyethersulfone Mixed Matrix Membrane: Effect of Nanocomposite Loading on the Antifouling Performance

Wan Ikhsan SN, Yusof N, Mat Nawi NI, Bilad MR, Shamsuddin N, Aziz F, et al.

Polymers (Basel), 2021 Jan 30;13(3).
PMID: 33573140 DOI: 10.3390/polym13030441

Membrane filtration is an attractive process in water and wastewater treatment, but largely restricted by membrane fouling. In this study, the membrane fouling issue is addressed by developing polyethersulfone (PES)-based mixed matrix membranes (MMMs) with the incorporation of hydrophilic nanoparticles as an additive. Ultrafiltration MMMs were successfully fabricated by incorporating different loadings of halloysite nanotube-ferrihydrates (HNT-HFO) into a polyethersulfone (PES) matrix and their performance was evaluated for the separation of bovine serum albumin (BSA) solution and oil/water emulsion. The results show that wettability is endowed to the membrane by introducing the additive aided by the presence of abundant -OH groups from the HFO. The loading of additive also leads to more heterogeneous surface morphology and higher pure water fluxes (516.33-640.82 L/m2h) more than twice that of the pristine membrane as reference (34.69 L/m2h) without affecting the rejection. The MMMs also provide much enhanced antifouling properties. The filtration results indicate that the flux recovery ratio of the modified membrane reached 100% by washing with only distilled water and a total flux recovery ratio of >98% ± 0.0471 for HNT-HFO-loaded membranes in comparison with 59% ± 0.0169 for pristine PES membrane.
Fulltext Rare but Potentially Fatal Presentations of Diffuse Large B-cell Lymphoma: Leukemic Phase or Hemophagocytic Syndrome in Bone Marrow

Wan Mohd Zohdi WA, Ismail AZ, Yusof N, Ithnin A, Shuib S, Masir N, et al.

Clin Pathol, 2022 01 09;15:2632010X211070774.
PMID: 35036912 DOI: 10.1177/2632010X211070774

Diffuse large B-cell lymphoma (DLBCL) is a type of non-Hodgkin Lymphoma commonly presenting as a solid tumor either by nodal or extra-nodal manifestations. Here we describe two atypical presentations of lymphoma, finally resulting in the diagnosis of DLBCL. Case 1: A 53-year-old man with a previous history of nasopharyngeal carcinoma presented with a two-week history of B-symptoms and hyperleukocytosis. Peripheral blood film showed 78% abnormal mononuclear cells. Immunohistochemical stain showing Ki-67 of 90%, negative c-myc, BCL2 and BCL6, and negative c-MYC with fluorescence in-situ hybridization studies on the trephine biopsy, concluded the diagnosis of CD5+ DLBCL of ABC subtype. He received intravenous cyclophosphamide and oral prednisolone for cytoreduction, followed by 6 cycles of chemo-immunotherapy. However, he succumbed due to severe sepsis after the completion of therapy. Case 2: A 56-year-old lady who was initially investigated for pyrexia of unknown origin was noted to have hemophagocytosis upon bone marrow aspirate examination. The bone marrow trephine biopsy revealed some atypical clusters of B-cells positive for CD20 which was inconclusive. PET-CT scan noted an enlarged hypermetabolic spleen without lymphadenopathy. Splenic biopsy with immunohistochemical studies revealed DLBCL of ABC subtype. The diagnosis was consistent with primary splenic DLBCL. She became unwell post splenic biopsy and was admitted to the intensive care unit where she passed away 2 weeks later from Candida and Sternotrophomonas septicemia. These cases highlight the atypical presentations of a common subtype of NHL in our center. Arriving at the definitive diagnosis can be difficult especially when patients are acutely ill, hampering the necessary invasive procedures for diagnosis. The outcomes of both cases are briefly discussed hoping to spread awareness among clinicians on the rare and acutely critical presentations of DLBCL.
Assessing sequence heterogeneity in Chlorellaceae DNA barcode markers for phylogenetic inference

Wong EB, Kamaruddin N, Mokhtar M, Yusof N, Khairuddin RFR

J Genet Eng Biotechnol, 2023 Oct 18;21(1):104.
PMID: 37851281 DOI: 10.1186/s43141-023-00550-5

Phylogenetic inference is an important approach that allows the recovery of the evolutionary history and the origin of the Chlorellaceae species. Despite the species' potential for biofuel feedstock production, their high phenotypic plasticity and similar morphological structures among the species have muddled the taxonomy and identification of the Chlorellaceae species. This study aimed to decipher Chlorellaceae DNA barcode marker heterogeneity by examining the sequence divergence and genomic properties of 18S rRNA, ITS (ITS1-5.8S rRNA-ITS2-28S rRNA), and rbcL from 655 orthologous sequences of 64 species across 31 genera in the Chlorellaceae family. The study assessed the distinct evolutionary properties of the DNA markers that may have caused the discordance between individual trees in the phylogenetic inference using the Robinson-Foulds distance and the Shimodaira-Hasegawa test. Our findings suggest that using the supermatrix approach improves the congruency between trees by reducing stochastic error and increasing the confidence of the inferred Chlorellaceae phylogenetic tree. This study also found that the phylogenies inferred through the supermatrix approach might not always be well supported by all markers. The study highlights that assessing sequence heterogeneity prior to the phylogenetic inference could allow the approach to accommodate sequence evolutionary properties and support species identification from the most congruent phylogeny, which can better represent the evolution of Chlorellaceae species.
Fulltext Confocal laser scanning microscope analysis on post-biofilm assessment of biofilmproducing osteomyelitic Staphylococcus aureus treated with new Gentamicin-Nigella sativa fusion emulsion (GNFE)

Yaakob, K.I., Mohd Shafri, M.A., Mohd Yusof, N., Mohamed, F.

Malaysian Journal of Microscopy, 2015;11(1):68-73.
MyJurnal

Biofilm complicates osteomyelitis as there is antibiotic resistance and toxicity involved. In order to overcome the challenges of current treatment, gentamicin, the current antibiotic of choice for osteomyelitis, is fused with Nigella sativa oil to form an emulsion. Its efficacy as anti-biofilm agent is assessed using confocal laser scanning microscope (CLSM) against different strains of biofilm-producing Staphylococcus aureus. These strains of S.aureus were first allowed to express biofilm before being exposed for 24 hours to the emulsion with (0.1% (w/v) gentamicin; 40.2% (v/v) N.sativa. Later, the emulsion was removed and the biofilm was stained with fluorescence staining. The slides were viewed under CLSM at 100 times resolution. 3D images of biofilm were reconstructed, using Image J software, to measure the thickness of biofilm and viability of bacteria cells. Results revealed that the emulsion significantly reduced biofilm thickness compared to gentamicin and N.sativa alone in all strains of S.aureus (Tukey’s test p < 0.05). The emulsion was also able to produce more than 80% and 15% surface percentage (%) of non-viable (dead) bacteria in the sensitive and resistant strain, respectively, at a significant level when compared to gentamicin and N.sativa (Tukey’s test p < 0.05). As a conclusion, this new fusion of gentamicin-N.sativa may be effective towards the biofilm of S.aureus, and can be developed further as a new promising anti-biofilm agent in osteomyelitis.
Fulltext Deep-Freezing Temperatures During Irradiation Preserves the Compressive Strength of Human Cortical Bone Allografts: A Cadaver Study

Yang Harmony TC, Yusof N, Ramalingam S, Baharin R, Syahrom A, Mansor A

Clin Orthop Relat Res, 2022 Feb 01;480(2):407-418.
PMID: 34491235 DOI: 10.1097/CORR.0000000000001968

BACKGROUND: Gamma irradiation, which minimizes the risk of infectious disease transmission when human bone allograft is used, has been found to negatively affect its biomechanical properties. However, in those studies, the deep-freezing temperature during irradiation was not necessarily maintained during transportation and sterilization, which may have affected the findings. Prior reports have also suggested that controlled deep freezing may mitigate the detrimental effects of irradiation on the mechanical properties of bone allograft.
QUESTION/PURPOSE: Does a controlled deep-freezing temperature during irradiation help preserve the compressive mechanical properties of human femoral cortical bone allografts?
METHODS: Cortical bone cube samples, each measuring 64 mm3, were cut from the mid-diaphyseal midshaft of five fresh-frozen cadaver femurs (four male donors, mean [range] age at procurement 42 years [42 to 43]) and were allocated via block randomization into one of three experimental groups (with equal numbers of samples from each donor allocated into each group). Each experimental group consisted of 20 bone cube samples. Samples irradiated in dry ice were subjected to irradiation doses ranging from 26.7 kGy to 27.1 kGy (mean 26.9 kGy) at a deep-freezing temperature below -40°C (the recommended long-term storage temperature for allografts). Samples irradiated in gel ice underwent irradiation doses ranging from 26.2 kGy and 26.4 kGy (mean 26.3 kGy) in a freezing temperature range between -40°C and 0°C. Acting as controls, samples in a third group were not subjected to gamma irradiation. The mechanical properties (0.2% offset yield stress, ultimate compression stress, toughness, and the Young modulus) of samples from each group were subsequently evaluated via axial compression loading to failure along the long axis of the bone. The investigators were blinded to sample group during compression testing.
RESULTS: The mean ultimate compression stress (84 ± 27 MPa versus 119 ± 31 MPa, mean difference 35 [95% CI 9 to 60]; p = 0.005) and toughness (3622 ± 1720 kJ/m3 versus 5854 ± 2900 kJ/m3, mean difference 2232 [95% CI 70 to 4394]; p = 0.009) of samples irradiated at a higher temperature range (-40°C to 0°C) were lower than in those irradiated at deep-freezing temperatures (below -40°C). The mean 0.2% offset yield stress (73 ± 28 MPa versus 109 ± 38 MPa, mean difference 36 [95% CI 11 to 60]; p = 0.002) and ultimate compression stress (84 ± 27 MPa versus 128 ± 40 MPa, mean difference 44 [95% CI 17 to 69]; p < 0.001) of samples irradiated at a higher temperature range (-40°C to 0°C) were lower than the nonirradiated control group samples. The mean 0.2% offset yield stress (73 ± 28 MPa versus 101 ± 28 MPa, mean difference 28 [95% CI 3 to 52]; p = 0.02; effect size = 1.0 [95% CI 0.8 to 1.2]) of samples irradiated at higher temperature range (-40°C to 0°C) were no different with the numbers available to those irradiated at deep-freezing temperature. The mean toughness (3622 ± 1720 kJ/m3 versus 6231 ± 3410 kJ/m3, mean difference 2609 [95% CI 447 to 4771]; p = 0.02; effect size = 1.0 [95% CI 0.8 to 1.2]) of samples irradiated at higher temperature range (-40°C to 0°C) were no different with the numbers available to the non-irradiated control group samples. The mean 0.2% offset yield stress, ultimate compression stress, and toughness of samples irradiated in deep-freezing temperatures (below -40°C) were not different with the numbers available to the non-irradiated control group samples. The Young modulus was not different with the numbers available among the three groups.
CONCLUSION: In this study, maintenance of a deep-freezing temperature below -40°C, using dry ice as a cooling agent, consistently mitigated the adverse effects of irradiation on the monotonic-compression mechanical properties of human cortical bone tissue. Preserving the mechanical properties of a cortical allograft, when irradiated in a deep-freezing temperature, may have resulted from attenuation of the deleterious, indirect effects of gamma radiation on its collagen architecture in a frozen state. Immobilization of water molecules in this state prevents radiolysis and the subsequent generation of free radicals. This hypothesis was supported by an apparent loss of the protective effect when a range of higher freezing temperatures was used during irradiation.
CLINICAL RELEVANCE: Deep-freezing temperatures below -40°C during gamma irradiation may be a promising approach to better retain the native mechanical properties of cortical bone allografts. A further study of the effect of deep-freezing during gamma radiation sterilization on sterility and other important biomechanical properties of cortical bone (such as, tensile strength, fracture toughness, and fatigue) is needed to confirm these findings.

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