Displaying publications 1 - 20 of 82 in total

  1. Yusof N
    Cell Tissue Bank, 2018 Jun;19(2):175-186.
    PMID: 29022196 DOI: 10.1007/s10561-017-9651-4
    Under the auspices of the IAEA tissue banking programme on "Radiation Sterilisation of Tissue Graft" conducted from 1985 to 2004, many scientists and surgeons were involved in various regional research and development (R&D) projects mainly in dealing with radiation dose selection, radiation effects on human tissues and quality system in radiation sterilisation. New findings on radiation effects, tissue processing and preservation were shared during the regional and interregional meetings and workshops. Many tissue banks started to use radiation (25 kGy) to sterilize tissue grafts for tissue safety and efficacy and still continue to use it. The IAEA Code of Practice for Radiation Sterilization of Tissues Allografts developed in 2007 offered simpler methods to conduct radiation dose setting and dose validation experiments for tissue grafts. Advances in dose selection and dose mapping are continued under the quality management system when banks need to be certified to continue their operation. The combination of good tissue processing and preservation as well as good radiation practice will ensure the tissue products are properly sterilised thus safe and of high quality. Experience in meeting challenges in using radiation sterilisation and achievements reported by the tissue bankers are shared here.
  2. Ainul Hafiza A.H., Yusof N., Maimon A.
    A laboratory study was carried out to study the microbiological quality of local honey and its potential as an antibacterial agent. Five local honeys namely, Belimbing, Gelam (Sample 1,2, and 3), Durian (Sample 1 and 2), Kelapa and Tualang were studied. Microbial colony count of each sample was determined using filtration method. Screening for antibacterial action against Staphylococcus aureus was carried out using agar diffusion method. The result showed that all samples had low colony counts ranging from 37 cfu/ml in Kelapa honey to 161 cfu/ml in Durian honey (Sample 2). All samples showed a very clear zone of inhibition for bacterial growth and there was significant difference (ANOVA, p<0.05) among the samples. Belimbing honey showed the biggest diameter (2.1cm) and Gelam honey – Sample 3 had the smallest (1.7 cm).
    [Kajian ini dijalankan untuk mengkaji kualiti mikrobiologi madu tempatan dan keupayaannya sebagai agen antibakteria. Lima madu tempatan iaitu Belimbing, Gelam (Sampel 1, 2, dan 3), Durian (Sampel 1 dan 2), Kelapa dan Tualang telah dikaji. Bilangan koloni mikrob ditentukan menggunakan kaedah turasan. Sifat antibakteria terhadap Staphylococcus aureus pula dikaji menggunakan kaedah serapan agar. Keputusan menunjukkan bahawa semua sampel mempunyai bilangan koloni yang rendah sekitar 37 cfu/ml dalam madu Kelapa hingga 161 cfu/ml dalam madu Durian – Sampel 2. Semua sampel menunjukkan kesan rencatan pertumbuhan bakteria dan terdapat perbezaan ketara (ANOVA, p
  3. Tai KM, Sulong AF, Mohd. Yusof N
    IIUM Medical Journal Malaysia, 2019;18(3):96-103.
    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.
  4. Jamal, P., Jaswir, I., Yusof, N., Jami, M.S.
    Gelatin from fish skin is known to be an alternative source for mammalian gelatin. However, it has weaker properties compared to bovine and porcine gelatin, which limits its use in the industry. The conventional method for fish gelatin extraction requires long production time and could cause serious water pollution and chemical treatments are often being used to enhance the yield of fish gelatin and its properties but it may affect the amino acid content of the gelatin. In this regard, High-Pressure Processing (HPP) is a novel method suggested for fish gelatin extraction. The HPP method is classified as green technology as it requires low electricity throughout the process. This study will discuss the impact of HPP the technique gelatin extracted from fish skin. Skins from four types of fish, namely red tilapia (Oreochromis niloticus), black tilapia (Oreochromis mossambicus), grouper (Epinephelus areolatus) and threadfin bream (Nemipterus tambuloides), were used. High pressure was applied at either pretreatment in citric acid solution or during thermal extraction; and the pressure was maintained at 250 MPa with pressure holding time of 10 minutes and 18 hours of water extraction. Gelatin extract from traditional acid-base method was prepared as a standard for comparison. The study found that there was an increment in the yield of gelatin and the concentration of gelatin extract, and the pre-treatment time was also reduced.
  5. Yusof, N., Jaswir, I., Jamal, P., Jami, M.S., Octavianti, F.
    Extraction of gelatin using traditional acid-base pretreatment method has several limitations
    such as time consuming and causes serious water pollution. Chemical treatment often being used
    as an alternative process to overcome the weaknesses of the conventional method. However,
    excessive chemical elements would damage the structure of the gelatin due to its high sensitivity
    to the acid content. High Pressure Processing (HPP) is a novel and environmental friendly
    method that has been suggested to assist gelatin extraction. Pressurization during pretreatment
    could reduce the extraction time and amount of acid used. It also has a potential in enhancing the
    properties of the gelatin extract and increasing the gelatin yield. In this research, One-Factor-
    at-Time (OFAT) and optimization study were done to determine the optimum parameters for
    extraction of gelatin assisted by HPP from red tilapia skin. Four parameters; applied pressure,
    pressure holding time, ratio of acid to skin and extraction time have been selected for the OFAT
    design and concentration of the gelatin extract and percentage of yield gelatin were evaluated.
    From OFAT, optimum technical parameters for response surface optimization design were 250
    MPa pressure, 7.5 ml of acid to 1 g of skin and 12 hours extraction time. Pressure holding
    time was fixed for 10 min. FCCCD has been used for optimization study. Results from the
    data shows that the optimum conditions for gelatin extraction from red tilapia skin were 250
    MPa for pressure, 10 min of pressure holding time, 7.5 ml of acid for 1 g of skin and 12 hours
    of extraction time while the maximum concentration and yield were 19.51 mg/ml and 32.04%
    (320.4 mg/g), respectively. These findings proved that HPP could increase the concentration
    and the yield of the gelatin while reducing the chemical waste and shortening the extraction
  6. Yaakob, K.I., Mohd Shafri, M.A., Mohd Yusof, N., Mohamed, F.
    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.
  7. Ariffin, A.A., Chan, H.H., Yusof, N., Mohd, S., Ng, W.M., Mansor A.
    JUMMEC, 2019;22(1):66-71.
    Freeze drying is a dehydration method to dry bone under freezing environment, enabling removal of water
    with no or minimial effects on bone strength and durability. Larger size bones obviously require longer freeze
    drying time to reduce water content to the required level for long term storage at room temperature. For small
    size bone cubes or chips, it is a normal practice to pool cortical and cancellous bones for freeze drying. The
    study was aimed at determining if different type of bones of the same size influence the drying time. Human
    bone cubes of 10 mm x 10 mm x 10 mm were prepared from cortical bone of tibiae and cancellous bone from
    femoral heads. The bone cubes were freeze dried to reduce water content to less than 6%. Moisture content
    was monitored using gravimetric method.Weight and density of cortical bone were significantly higher than
    cancellous bone despite of having similar small size (p
  8. Yusof N, Morales Pedraza J
    Cell Tissue Bank, 2009 May;10(2):115-7.
    PMID: 18581259 DOI: 10.1007/s10561-008-9085-0
    The IAEA was instrumental in developing the first Malaysian tissue bank at University Hospital of Universiti Sains Malaysia (HUSM), Kubang Kerian, Kelantan in early 1990s and it was officiated as National Tissue Bank in 1994. Up to date, 38 government and private hospitals have received a supply from the bank. Bone allografts in term of bone chips, morsalised bone and long bones are procured from Malaysian donors. Almost thirty students from Malaysia graduated in the training courses carried out in Singapore since 1998 at regional and interregional levels. Organ donation is more readily accepted by the public at the moments, perhaps due to the vast promotion and advertisement given by the local newspapers and other media, but gradually tissue donation is catching up as well.
  9. Low KL, Idris A, Mohd Yusof N
    Food Chem, 2020 Mar 01;307:125631.
    PMID: 31634761 DOI: 10.1016/j.foodchem.2019.125631
    Lutein available in the current market is derived from marigold petals. However, extensive studies showed that microalgae are rich in lutein content and potentially exploitable for its dietary and other industrial applications. In this study, microwave assisted binary phase solvent extraction method (MABS) was the novel protocol being developed and optimized to achieve maximum lutein recovery from microalgae Scenedesmus sp. biomass. Results showed that 60% potassium hydroxide solution with acetone in the ratio of 0.1 (ml/ml) was the ideal binary phase solvent composition. Empirical model developed using response surface methodology revealed highest lutein content can be recovered through MABS extraction method at 55 °C treatment temperature, 36 min in extraction time, 0.7 (mg/ml) for biomass to solvent ratio, 250 Watt microwave power and 250 rpm stirring speed. This optimized novel protocol had increased the amount of lutein recovered by 130% and shorten the overall extraction time by 3-folds.
  10. Siti Zaharah, R., Noranizan, M., Son, R., Roselina, K., Yusof, N. L., Koh, P. C., et al.
    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.
  11. Yusoff K, Razak TA, Yusof N, Rafee NM
    Int J Clin Pract, 1999 Jun;53(4):277-80.
    PMID: 10563072
    ACE inhibitors are important therapeutic agents in controlling hypertension, correcting some of its pathophysiological derangement and improving its prognosis. While there are many such agents, there may be some important differences between them. This placebo run-in, double blind, crossover study, using 24-hour ambulatory blood pressure monitoring, compares the efficacy of perindopril 4-8 mg and enalapril 10-20 mg as once daily antihypertensive agents on 32 patients. For diastolic blood pressure (DBP), perindopril had a placebo-corrected peak (P) reduction of blood pressure (BP) of -6.4 +/- 1.3 mmHg vs its placebo-corrected trough (T) of -5.2 +/- 1.7 mmHg. Enalapril had a reduction in DBP of -8.5 +/- 1.3 mmHg (P) and -5.7 +/- 1.7 mmHg (T). For systolic blood pressure (SBP), perindopril had a reduction of -7.5 +/- 1.6 mmHg (P) vs -7.3 +/- 2.2 mmHg (T) compared to enalapril with -10.8 +/- 1.6 mmHg (P) vs -8.3 +/- 2.3 mmHg (T). Placebo-corrected trough-to-peak ratio (SBP/DBP) for perindopril was 0.97/0.81 vs 0.77/0.67 for enalapril. There was no difference noted in 24-hour mean BP, area under the curve or post-dose casual BP measurements. Both perindopril and enalapril were well tolerated and the two treatment groups had similar safety profiles. Perindopril thus had a predictable and sustained blood pressure effect giving a 24-hour cover for the patient without excessive peak effect or poor trough effect.
  12. Mohd S, Yusof N, Ramalingam S, Ng WM, Mansor A
    Malays Orthop J, 2017 Jul;11(2):1-6.
    PMID: 29021871 MyJurnal DOI: 10.5704/MOJ.1707.004
    Despite increasing use of bone graft in Malaysia, there was still lack of data to quantify knowledge level on bone banking among orthopaedic community who are involved in transplantation related work. Therefore, a survey on awareness in tissue banking specifically bone banking, usage and choice of bone grafts was conducted. From 80 respondents, 82.5% were aware about tissue banking however only 12.5% knew of the existence of tissue banks in Malaysia. Femoral head was the bone allograft most often used as a substitute to autograft. Only 34.8% respondents preferred irradiated bone grafts whilst 46.9% preferred nonirradiated, indicating the need to educate the importance of radiation for sterilising tissues. Exhibition was the most preferred medium for awareness programme to disseminate information about bone banking in the orthopaedic community. The professional awareness is necessary to increase the knowledge on the use of bone graft, hence to increase bone transplantation for musculoskeletal surgeries in the country.
  13. Onubi HO, Yusof N, Hassan AS
    Environ Sci Pollut Res Int, 2022 Jan;29(4):5431-5444.
    PMID: 34420175 DOI: 10.1007/s11356-021-15705-5
    Studies have proven that client satisfaction (CS) is greatly affected by the nature of construction practices on site. However, not much attention has been given to CS in projects that adopt green construction practices (GCPs). This study examines the effect of GCPs on CS, and the means by which CS can be achieved through health and safety performance (HSP). This study also analyses how the relationship between HSP and CS could vary depending on the level of GCPs adopted. A questionnaire with 27 items drawn from literature was used in collecting data from class A contractors in Nigeria. The study's hypotheses were tested using the partial least squares structural equation modelling (PLS-SEM) technique. The findings of the study reveal that GCPs have a positive effect on CS. HSP proved to only partially mediate the relationship between GCPs and CS. The findings also show that the effect of HSP on CS is moderated by GCPs with the stronger effect from projects with low adoption of GCPs. The study's findings highlight the pivotal role of HSP in ensuring CS in construction projects that adopt GCPs. This study makes practical contributions to the body of existing knowledge by highlighting the need for concerted efforts by contractors such as investing in health and safety training and ensuring site workers wear personal protective equipment aimed at adhering to acceptable health and safety standards. This can be achieved through provision of funds for safety activities, monitoring, and supervision of workers to guarantee HSP which translates to CS while adopting GCPs. However, the obstacles to these are the lack of safety culture by construction organizations, lack of enlightenment on the part of construction site workers, and poor safety climate on the construction project site. Additionally, the study provides greater insight on the practice of green construction among contractors by showing that the effect of HSP on CS would differ considerably on account of the level of GCPs adopted.
  14. Fallahiarezoudar E, Ahmadipourroudposht M, Idris A, Mohd Yusof N
    Mater Sci Eng C Mater Biol Appl, 2015 Mar;48:556-65.
    PMID: 25579957 DOI: 10.1016/j.msec.2014.12.016
    The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems.
  15. Yousuf R, Abdul Aziz S, Yusof N, Leong CF
    Indian J Hematol Blood Transfus, 2014 Sep;30(3):208-10.
    PMID: 25114411 DOI: 10.1007/s12288-012-0211-6
    We report a 47-year-old Malay lady, para 4 + 1, with known medical history of hypertension whom presented at Emergency Department with severe anaemia, most likely secondary to menorrhagia caused by uterine fibroids. Her haemoglobin was 5.5 g/dl and she was transfused with three units of packed cell without any adverse reaction, her haemoglobin level increased to 9.8 g/dl. She was then planned for total abdominal hysterectomy and bilateral salpingo-oophorectomy later. Four months later when she came for the elective surgery, her pre transfusion investigations showed blood group as B Rh D positive, with a probable R1R1 phenotype. Her antibody screening was positive in all the three panel cells. Further testings showed a negative Direct Coomb's test and negative autocontrol, antibody identification showed pan-agglutination reaction on all 11 panel cells with enzyme enhancement. Patient's red cell phenotype was Jk(a-b-). Anti-Jk3 was suspected and further confirmed in the reference laboratory by phenotyping as well as negative urea lysis test. This case report highlights an extremely rare but clinically significant anti-JK3 antibody detected during pretransfusion testing. This phenotype is rare in the white population, more commonly seen in various polynesians. Increased awareness among the blood bank personnel regarding the variability of the blood group phenotype and the capricious nature of the Kidd antibodies may contribute to the better management of these patients.
  16. Zahari NK, Sheikh Ab Hamid S, Yusof N
    Cell Tissue Bank, 2015 Mar;16(1):55-63.
    PMID: 24647964 DOI: 10.1007/s10561-014-9438-9
    Preserved human amniotic membrane either air dried or glycerol preserved has been used effectively to treat superficial and partial thickness wounds without leaving any obvious hypertrophic scar. The preserved amnion, sterilised by ionising radiation, is known as an effective barrier for heat, fluid and protein loss while adheres nicely on wound. Air drying slightly reduced the oxygen transmission rate (OTR) of the amnion and the value significantly dropped after 15 kGy (p < 0.05). Glycerol preservation significantly reduced (p < 0.05) the OTR indicating less oxygen transmitted through the well structured cells of the amnion. Increase in the OTR with the increasing radiation doses up to 35 kGy possibly due to direct effects of radiation that resulted in large intercellular gaps. Both preservation methods significantly increased (p < 0.05) the water vapour transmission rate (WVTR). However, the low WVTR in the air dried amnion at 15 and 25 kGy was postulated due to cross-linking of collagen. Changes in the biophysical properties can be linked to direct and indirect effects of radiation on collagen bundles. The radiation dose of 25 kGy caused no adverse effect on biophysical properties hence it is still acceptable to sterilize both the air dried and the glycerol preserved amnions.
  17. Yousuf R, Abdul Aziz S, Yusof N, Leong CF
    Indian J Hematol Blood Transfus, 2013 Jun;29(2):65-70.
    PMID: 24426338 DOI: 10.1007/s12288-012-0155-x
    Red blood cell alloimmunization is a common complication among the transfusion recipients. In Malaysia, multiple ethnicity causes genetic heterogeneity among the population which in turn can cause a wide variation of antibody. The objective of this study was to analyse the red cell alloantibody detected during the pre-transfusion testing. This was a cross-sectional study done in the blood bank of Universiti Kebangsaan Malaysia Medical Centre during the period of January-December 2010. The data was retrieved from the hospital laboratory information system. A total of 24,263 patients' blood samples were subjected for pre-transfusion testing. Antibody screening was done using an indirect antiglobulin test method. The positive samples were further identified for antibody specificity. Antibody screening tests were positive in 184 patients out of 24,263 samples with the incidence of 0.76 %. Autoantibodies and alloantibodies were detected in 39/184 (21.2 %) and 140/184 (76.1 %) of the patients respectively. In five patients (2.7 %) the antibody specificity remained undetermined. Total 161 alloantibodies were identified. The suspected Anti-Mia alloantibody was observed most frequently (49/161, 30.4 %) followed by anti-E (30/161, 18.6 %) and anti-D (22/161, 13.7 %). Anti-E and anti-c were the most common combination of multiple alloantibodies. In view of the high incidence of suspected Anti-Mia antibodies, more efforts are needed to look into the techniques for confirmation of the Anti-Mia antibodies. Besides that, we suggested that all multiply transfused patients should be phenotyped for the Rh system and to supply Rh phenotype specific blood in order to limit alloimmunization.
  18. Abdollahi Y, Abdullah AH, Gaya UI, Zainal Z, Yusof NA
    Environ Technol, 2012 Jun;33(10-12):1183-9.
    PMID: 22856288
    The effective removal of o-cresol is currently both an environmental and economic challenge. ZnO is not only an efficient photocatalyst but is also cost effective, as its photoabsorption can extend from the ultraviolet (UV) to the visible range thereby allowing the use of inexpensive visible light sources, such as sunlight. The principal objective of the present work is to investigate the visible light-driven removal of o-cresol from aqueous solution in the presence of 1.0 wt% Mn-doped ZnO. To measure the efficiency ofphotodegradation, the variables studied included the amount ofphotocatalyst, concentration of o-cresol, pH and irradiation time. The concentration ofo-cresol and residual organic carbon was monitored using a UV-visible spectrophotometer, ultra high-pressure liquid chromatography and a total organic carbon analyser. The optimum conditions under which the photodegradation of o-cresol was most favourable corresponded to 1.5 g/l ZnO, 35 ppm o-cresol and pH 9. The ZnO-1 wt% Mn photoprocess has demonstrated reusability for more than three times, which warrants its scale-up from laboratory- to in industrial-scale application.
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