Displaying publications 1 - 20 of 156 in total

Abstract:
Sort:
  1. Fulltext Physio-Chemical Analysis of Amide and Amine Poly(dimethylsiloxane)-Modified Defoamer for Efficient Oil-Water Separation
    Hassan A, Jumbri K, Ramli A, Borhan N
    ACS Omega, 2021 Jun 15;6(23):14806-14818.
    PMID: 34151062 DOI: 10.1021/acsomega.1c00350
    The formation of foam due to the injection of surfactant foam in FAWAG causes significant problems in the oil well production and separation facilities. The excessive foam can lead to the reduction of the separator capacity as well as its efficiency. A defoamer is needed to break and destroy the foam in the separator. There are many commercially available defoamer agents in the market, but not all defoamers are suitable for every application. For this reason, four modified silicone-based defoamers were successfully synthesized and characterized based on the data obtained from the screening process using various commercial defoamers. The performance of modified defoamers was evaluated using TECLIS FoamScan that imitate real conditions of treatment. The results show that all four of the modified silicone-based defoamers, especially amide-terminated-modified defoamers (S2) showed excellent performance as a defoaming agent to mitigate foam in specific conditions. The best-case condition for the modified defoamer to perform was at a high temperature (60 °C), gas flow rate of 1.0 L/min, and low ration concentration of the surfactant to brine (30:70). The study on the bubble count and distribution using a KRÜSS Dynamic Foam Analyzer revealed that S2 excellently contributes to the formation of unstable foam that can fasten foam destruction in the foaming system.
  2. Fulltext Density Functional Theory Studies on New Possible Biobased Gemini Corrosion Inhibitors Derived from Fatty Hydrazide Derivatives
    Hassan A, Numin MS, Jumbri K, Kee KE, Borhan N, Nik Mohamed Daud NMR, et al.
    ACS Omega, 2023 Jul 04;8(26):23945-23952.
    PMID: 37426258 DOI: 10.1021/acsomega.3c02435
    Several new possible biobased corrosion inhibitors derived from fatty hydrazide derivatives were analyzed using quantum chemical calculations via the density functional theory method to investigate the chemical reactivity and inhibition efficiencies against corrosion in metal steel. The study confirmed that the fatty hydrazides showed significant inhibitive performances based on their electronic properties, revealing band gap energies of 5.20 to 7.61 eV between the HOMO and LUMO. These energy differences decreased from 4.40 to 7.20 eV when combined with substituents of varying chemical compositions, structures, and functional groups, associated with higher inhibition efficiency. The most promising fatty hydrazide derivatives are terephthalic acid dihydrazide combined with a long-chain alkyl chain, which resulted in the lowest energy difference of 4.40 eV. Further inspection showed that the fatty hydrazide derivatives' inhibitive performances increased with increasing carbon chain length [from 4 (4-s-4) to 6 (6-s-6)], with a concomitant increase and decrease in hydroxyl and carbonyl groups, respectively. Fatty hydrazide derivatives containing aromatic rings also showed increased inhibition efficiencies following their contribution to improve the compounds' binding ability and adsorption on the metal surface. Overall, all data were consistent with previously reported findings, envisaging the potential of fatty hydrazide derivatives as effective corrosion inhibitors.
  3. Motorcycle-related spinal injury: crash characteristics
    Zulkipli ZH, Abdul Rahmat AM, Mohd Faudzi SA, Paiman NF, Wong SV, Hassan A
    Accid Anal Prev, 2012 Nov;49:237-44.
    PMID: 23036400 DOI: 10.1016/j.aap.2011.12.011
    This study presents an analysis of crash characteristics of motorcyclists who sustained spinal injuries in motorcycle crashes. The aim of the study is to identify the salient crash characteristics that would help explain spinal injury risks for motorcyclists. Data were retrospectively collected from police case reports that were archived at MIROS from year 2005 to 2007. The data were categorized into two subcategories; the first group was motorcycle crashes with spinal injury (case) and the second group was motorcycle crashes without spinal injury (control). A total of 363 motorcyclists with spinal injury and 873 motorcyclists without spinal injury were identified and analyzed. Descriptive analysis and multivariate analysis were performed in order to determine the odds of each characteristic in contributing to spinal injury. Single vehicle crash, collision with fixed objects and crash configuration were found to have significant influence on motorcyclists in sustaining spinal injury (p<0.05). Although relatively few than other impact configurations, the rear-end impacted motorcyclist shows the highest risk of spinal injury. Helmets have helped to reduce head injury but they did not seem to offer corresponding protection for the spine in the study. With a growing number of young motorcyclists, further efforts are needed to find effective measures to help reduce the crash incidents and severity of spinal injury. In sum, the study provides some insights on some vital crash characteristics associated with spinal injury that can be further investigated to determine the appropriate counter-measures and prevention strategies to reduce spinal injury.
  4. Tualang honey supplement improves memory performance and hippocampal morphology in stressed ovariectomized rats
    Al-Rahbi B, Zakaria R, Othman Z, Hassan A, Mohd Ismail ZI, Muthuraju S
    Acta Histochem, 2014 Jan;116(1):79-88.
    PMID: 23810156 DOI: 10.1016/j.acthis.2013.05.004
    Recently, our research team has reported that Tualang honey was able to improve immediate memory in postmenopausal women comparable with that of estrogen progestin therapy. Therefore the aim of the present study was to examine the effects of Tualang honey supplement on hippocampal morphology and memory performance in ovariectomized (OVX) rats exposed to social instability stress. Female Sprague-Dawley rats were divided into six groups: (i) sham-operated controls, (ii) stressed sham-operated controls, (iii) OVX rats, (iv) stressed OVX rats, (v) stressed OVX rats treated with 17β-estradiol (E2), and (vi) stressed OVX rats treated with Tualang honey. These rats were subjected to social instability stress procedure followed by novel object recognition (NOR) test. Right brain hemispheres were subjected to Nissl staining. The number and arrangement of pyramidal neurons in regions of CA1, CA2, CA3 and the dentate gyrus (DG) were recorded. Two-way ANOVA analyses showed significant interactions between stress and OVX in both STM and LTM test as well as number of Nissl-positive cells in all hippocampal regions. Both E2 and Tualang honey treatments improved both short-term and long-term memory and enhanced the neuronal proliferation of hippocampal CA2, CA3 and DG regions compared to that of untreated stressed OVX rats.
  5. Seasonality of Anopheles aconitus mosquitoes, a secondary vector of malaria, in an endemic village near the Malaysia-Thailand border
    Rahman WA, Abu Hassan A, Adanan CR
    Acta Trop, 1993 Dec;55(4):263-5.
    PMID: 8147283
  6. The prevalence of Plasmodium falciparum and P. vivax in relation to Anopheles maculatus densities in a Malaysian village
    Rahman WA, Abu Hassan A, Adanan CR, Rashid MR
    Acta Trop, 1993 Dec;55(4):231-5.
    PMID: 8147279
    Blood from most of the residents of a remote village in northern peninsular Malaysia, bordering Thailand, was examined for malaria parasites monthly for 1 year. Plasmodium vivax was the commonest infection, but P. falciparum and mixed infections also occurred. Monthly collections of the malaria vector, Anopheles maculatus showed a positive correlation between mosquito densities and malaria positivity in the human population and a negative correlation with rainfall.
  7. A Bilayer Engineered Skin Substitute for Wound Repair in an Irradiation-Impeded Healing Model on Rat
    Mohd Hilmi AB, Hassan A, Halim AS
    Adv Wound Care (New Rochelle), 2015 May 1;4(5):312-320.
    PMID: 26005597
    Objective: An engineered skin substitute is produced to accelerate wound healing by increasing the mechanical strength of the skin wound via high production of collagen bundles. During the remodeling stage of wound healing, collagen deposition is the most important event. The collagen deposition process may be altered by nutritional deficiency, diabetes mellitus, microbial infection, or radiation exposure, leading to impaired healing. This study describes the fabrication of an engineered bilayer skin substitute and evaluates its effectiveness for the production of collagen bundles in an impaired healing model. Approach: Rats were exposed to 10 Gy of radiation. Two months postirradiation, the wounds were excised and treated with one of three skin replacement products: bilayer engineered skin substitutes, chitosan skin templates, or duoderm(©). The collagen deposition was analyzed by hematoxylin and eosin staining. Results: On day 21 postwound, the irradiated wounds displayed increased collagen bundle deposition after treatment using bilayer engineered skin substitutes (3.4±0.25) and chitosan skin templates (3.2±0.58) compared with duoderm (2.0±0.63). Innovation: We provide the first report on the fabrication of bilayer engineered skin substitutes using high density human dermal fibroblasts cocultured with HFSCs on chitosan skin templates. Conclusion: The high density of fibroblasts significantly increases the penetration of cells into chitosan skin templates, contributing to the fabrication of bilayer engineered skin substitute.
  8. A Scoping Review of Effective Teaching Strategies in Surface Anatomy
    Abu Bakar YI, Hassan A, Yusoff MSB, Kasim F, Abdul Manan Sulong H, Hadie SNH
    Anat Sci Educ, 2021 Mar 01.
    PMID: 33650315 DOI: 10.1002/ase.2067
    To become skilled physicians, medical students must master surface anatomy. However, the study of surface anatomy is less emphasized in medical and allied health science curricula, and the time devoted to direct engagement with the human body is limited. This scoping review was designed to answer one research question: "What are the elements and strategies that are effective in teaching surface anatomy?" The review was performed using a five-stage scoping review framework, including research question identification, relevant study identification, study selection, data charting, and result collating and reporting. Three databases were searched using two search terms combined with a Boolean operator: "teaching" and "surface anatomy." The initial pool of 3,294 sources was assessed for duplication, and study eligibility was evaluated using inclusion and exclusion criteria. Data were abstracted from 26 original articles by one researcher and verified by two other researchers. A thematic analysis was performed, and several elements of effective teaching strategies for surface anatomy were identified, namely contextualized teaching, embracing experiential learning, and learning facilitation. This review revealed that a multimodal approach was most commonly used in surface anatomy instruction. Hence, future research should explore the effectiveness of multimodal teaching strategies that adopt the three aforementioned primary elements of effective teaching in an authentic learning environment. It is pertinent to clarify the effectiveness of these teaching strategies by evaluating their impact on student learning, organizational changes, and benefits to other stakeholders.
  9. Anatomy education environment measurement inventory: A valid tool to measure the anatomy learning environment
    Hadie SNH, Hassan A, Ismail ZIM, Asari MA, Khan AA, Kasim F, et al.
    Anat Sci Educ, 2017 Sep;10(5):423-432.
    PMID: 28135037 DOI: 10.1002/ase.1683
    Students' perceptions of the education environment influence their learning. Ever since the major medical curriculum reform, anatomy education has undergone several changes in terms of its curriculum, teaching modalities, learning resources, and assessment methods. By measuring students' perceptions concerning anatomy education environment, valuable information can be obtained to facilitate improvements in teaching and learning. Hence, it is important to use a valid inventory that specifically measures attributes of the anatomy education environment. In this study, a new 11-factor, 132-items Anatomy Education Environment Measurement Inventory (AEEMI) was developed using Delphi technique and was validated in a Malaysian public medical school. The inventory was found to have satisfactory content evidence (scale-level content validity index [total] = 0.646); good response process evidence (scale-level face validity index [total] = 0.867); and acceptable to high internal consistency, with the Raykov composite reliability estimates of the six factors are in the range of 0.604-0.876. The best fit model of the AEEMI is achieved with six domains and 25 items (X2  = 415.67, P 
  10. Targeted polymeric nanoparticle for anthracycline delivery in hypoxia-induced drug resistance in metastatic breast cancer cells
    Almoustafa HA, Alshawsh MA, Chik Z
    Anticancer Drugs, 2021 Aug 01;32(7):745-754.
    PMID: 33675612 DOI: 10.1097/CAD.0000000000001065
    Poly lactic-co-glycolic acid (PLGA) nanoparticles are intensively studied nanocarriers in drug delivery because of their biodegradability and biochemical characteristics. Polyethylene glycol (PEG) coating for nanocarriers gives them long circulation time in blood and makes them invisible to the reticuloendothelial system. Breast cancer cells have greater uptake of hyaluronic acid compared to normal cells as it binds to their overexpressed CD44 receptors. Since hypoxia plays an important role in cancer metastasis; we formulated PEG-PLGA nanoparticles coated with hyaluronic acid as targeted delivery system for doxorubicin (DOX) using nanoprecipitation method, and characterized them for chemical composition, size, surface charge, shape, and encapsulation efficiency. Then we tested them in vitro on hypoxia-optimized metastatic breast cancer cells. The nanoparticles were spherical with an average size of about 106 ± 53 nm, a negative surface charge (-15 ± 3 mV), and high encapsulation efficiency (73.3 ± 4.1%). In vitro investigation with hypoxia-elevated CD44 MDA-MB-231 cells showed that hyaluronic acid-targeted nanoparticles maintained their efficacy despite hypoxia-induced drug resistance unlike free DOX and nontargeted nanoparticles. In conclusion, this study revealed a simple third generation nanoparticle formulation for targeted treatment of hypoxia-induced drug resistance in breast cancer metastatic cells. Further, optimization is needed including In vivo efficacy and nanoparticle-specific pharmacokinetic studies.
  11. Fulltext Spring loaded plunger attachment for retention of removable partial denture: a case report
    Awang, R.A.R., Arief, E.M., Hassan, A.
    Archives of Orofacial Sciences, 2008;3(1):32-35.
    MyJurnal
    Since the establishment of implant in dentistry, the use of removable partial denture in replacing missing teeth apparently becomes less popular. The situation is made worse by the renowned limitations of removable partial denture. One of the obvious limitations of removable partial denture, especially in replacing missing anterior teeth is the unsightly view of metal used for retentive clasp. This case report describes the use of spring loaded plunger attachments as an alternative way to achieve retention and at the same time improving the aesthetic of the prosthesis.
  12. Fulltext Cluster Analysis Evaluating PM2.5, Occupation Risk and Mode of Transportation as Surrogates for Air-pollution and the Impact on Lung Cancer Diagnosis and 1-Year Mortality
    Abdul Wahab S, Hassan A, Latif MT, Vadiveel Y, Jeyabalan T, Soo CI, et al.
    Asian Pac J Cancer Prev, 2019 07 01;20(7):1959-1965.
    PMID: 31350951 DOI: 10.31557/APJCP.2019.20.7.1959
    Objective: Epidemiological studies have reported the close relationship between risk for lung cancers and air pollution
    in particular, for non-smoking related lung cancers. However, most studies used residential address as proxies which may
    not estimate accurately an individual’s air pollution exposure. Therefore, the aim of this study was to identify risk factors
    such as occupation and mode of transportation associated with lung cancer diagnosis and death. Methods: Subjects
    with lung cancer (n=514) were evaluated both by chart reviews for clinical data and interviews to determine residential
    address for ten years, main occupation and main mode of transportation. Annual particulate matter with diameter size
    less than 2.5 micrometre (PM2.5) concentration were calculated based on particulate matter with diameter size less than
    10 micrometre (PM10) data recorded by Malaysian Department of Environment. Logistic regression analysis, cluster
    analysis and the Cox regression analysis were performed to the studied variables. Results: This study concurred with
    previous studies that lung adenocarcinoma were diagnosed in predominantly younger, female non-smokers compared
    to the other types of lung cancers. Lung adenocarcinoma subjects had annual PM2.5 that was almost twice higher than
    squamous cell carcinoma, small cell carcinoma and other histological subtypes (p=0.024). Independent of smoking,
    the κ -means cluster analysis revealed two clusters in which the high risk cluster involves occupation risk with air
    pollution of more than four hours per day, main transportation involving motorcycle and trucks and mean annual PM2.5
    concentration of more than 30 based on residential address for more than ten years. The increased risk for the high-risk
    cluster was more than five times for the diagnosis of lung adenocarcinoma (OR=5.69, 95% CI=3.14-7.21, p<0.001).
    The hazard ratio for the high-risk cluster was 3.89 (95% CI=2.12-4.56, p=0.02) for lung adenocarcinoma mortality at
    1 year. Conclusion: High-risk cluster including PM2.5, occupation risk and mode of transportation as surrogates for
    air-pollution exposure was identified and highly associated with lung adenocarcinoma diagnosis and 1-year mortality.
  13. Fulltext Molecular basis of Rh blood group system in the Malaysian population
    Musa RH, Muhamad NA, Hassan A, Ayob Y, Yusoff NM
    Asian J Transfus Sci, 2015 Jan-Jun;9(1):48-54.
    PMID: 25722573 DOI: 10.4103/0973-6247.150951
    Rh molecular studies have been previously mainly conducted in Caucasians and African population. There is a limited data on the molecular basis for Rh genotypes among Asians.
  14. Fulltext Anatomy Education Environment Measurement Inventory (AEEMI): a cross-validation study in Malaysian medical schools
    Hadie SNH, Yusoff MSB, Arifin WN, Kasim F, Ismail ZIM, Asari MA, et al.
    BMC Med Educ, 2021 Jan 14;21(1):50.
    PMID: 33446203 DOI: 10.1186/s12909-020-02467-w
    BACKGROUND: The Anatomy Education Environment Measurement Inventory (AEEMI) evaluates the perception of medical students of educational climates with regard to teaching and learning anatomy. The study aimed to cross-validate the AEEMI, which was previously studied in a public medical school, and proposed a valid universal model of AEEMI across public and private medical schools in Malaysia.

    METHODS: The initial 11-factor and 132-item AEEMI was distributed to 1930 pre-clinical and clinical year medical students from 11 medical schools in Malaysia. The study examined the construct validity of the AEEMI using exploratory and confirmatory factor analyses.

    RESULTS: The best-fit model of AEEMI was achieved using 5 factors and 26 items (χ 2 = 3300.71 (df = 1680), P

  15. Fulltext Chitosan dermal substitute and chitosan skin substitute contribute to accelerated full-thickness wound healing in irradiated rats
    Mohd Hilmi AB, Halim AS, Jaafar H, Asiah AB, Hassan A
    Biomed Res Int, 2013;2013:795458.
    PMID: 24324974 DOI: 10.1155/2013/795458
    Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation.
  16. Fulltext Mood and memory function in ovariectomised rats exposed to social instability stress
    Al-Rahbi B, Zakaria R, Othman Z, Hassan A, Muthuraju S, Wan Mohammad WM
    Biomed Res Int, 2013;2013:493643.
    PMID: 23841073 DOI: 10.1155/2013/493643
    This study aims to compare the effects of social instability stress on memory and anxiety- and depressive-like behaviour between sham-operated controls and ovariectomised (OVX) rats. Forty adult female Sprague-Dawley rats (8 weeks old) were randomly divided into four groups, (n = 10 per group). These were non-stressed sham-operated control rats, stressed sham-operated control rats, non-stressed OVX rats, and stressed OVX rats. The rats were subjected to social instability stress procedure for 15 days. Novel object recognition, open field, and forced swim tests were conducted after the stress procedure. Serum estradiol, ACTH and corticosterone levels were measured using commercially available ELISA kits. Lower serum estradiol level and uterine weight with higher weight gain were observed in OVX rats compared to sham-operated controls. Serum ACTH, and corticosterone levels were higher in stressed compared to non-stressed groups. Memory deficit and anxiety- and depressive-like behaviour were significantly increased in stressed compared to non-stressed OVX rats but these changes were not seen in sham-operated controls. These results suggest that the high circulating corticosterone acts synergistically with low circulating estradiol to exert negative effects on mood and memory function.
  17. Fulltext Molecular mechanistic pathways underlying the anticancer therapeutic efficiency of romidepsin
    El Omari N, Lee LH, Bakrim S, Makeen HA, Alhazmi HA, Mohan S, et al.
    Biomed Pharmacother, 2023 Aug;164:114774.
    PMID: 37224749 DOI: 10.1016/j.biopha.2023.114774
    Romidepsin, also known as NSC630176, FR901228, FK-228, FR-901228, depsipeptide, or Istodax®, is a natural molecule produced by the Chromobacterium violaceum bacterium that has been approved for its anti-cancer effect. This compound is a selective histone deacetylase (HDAC) inhibitor, which modifies histones and epigenetic pathways. An imbalance between HDAC and histone acetyltransferase can lead to the down-regulation of regulatory genes, resulting in tumorigenesis. Inhibition of HDACs by romidepsin indirectly contributes to the anticancer therapeutic effect by causing the accumulation of acetylated histones, restoring normal gene expression in cancer cells, and promoting alternative pathways, including the immune response, p53/p21 signaling cascades, cleaved caspases, poly (ADP-ribose) polymerase (PARP), and other events. Secondary pathways mediate the therapeutic action of romidepsin by disrupting the endoplasmic reticulum and proteasome and/or aggresome, arresting the cell cycle, inducing intrinsic and extrinsic apoptosis, inhibiting angiogenesis, and modifying the tumor microenvironment. This review aimed to highlight the specific molecular mechanisms responsible for HDAC inhibition by romidepsin. A more detailed understanding of these mechanisms can significantly improve the understanding of cancer cell disorders and pave the way for new therapeutic approaches using targeted therapy.
  18. Design, synthesis, in vitro Evaluation and docking studies on dihydropyrimidine-based urease inhibitors
    Iftikhar F, Ali Y, Ahmad Kiani F, Fahad Hassan S, Fatima T, Khan A, et al.
    Bioorg Chem, 2017 10;74:53-65.
    PMID: 28753459 DOI: 10.1016/j.bioorg.2017.07.003
    In our previous report, we have identified 3,4-dihydropyrimidine scaffold as promising class of urease inhibitor in a structure based virtual screen (SBVS) experiment. In present study, we attempted to optimize the scaffold by varying C-5 substituent. The elongation of the C-5 chain was achieved by the reaction of C-5 ester with hydrazine leading to C-5 carbohydrazides which were further used as building blocks for the synthesis of fifteen new compounds having diverse moieties. A significantly higher in vitro urease inhibitory activity with IC50 values in submicromolar range was observed for semithiocarbazide derivatives (4a-c, 0.58-0.79µM) and isatin Schiff base derivative 5a (0.23µM). Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its key amino acid residues. The overall results of urease inhibition have shown that these compounds can be further optimized and developed as lead urease inhibitors.
  19. A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system
    Endut A, Jusoh A, Ali N, Wan Nik WB, Hassan A
    Bioresour Technol, 2010 Mar;101(5):1511-7.
    PMID: 19819130 DOI: 10.1016/j.biortech.2009.09.040
    The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate.
  20. Study of the D-- phenotype reveals erythrocyte membrane alterations in the absence of RHCE
    Flatt JF, Musa RH, Ayob Y, Hassan A, Asidin N, Yahya NM, et al.
    Br J Haematol, 2012 Jul;158(2):262-273.
    PMID: 22571328 DOI: 10.1111/j.1365-2141.2012.09149.x
    Red cells with the D-- phenotype do not express the RHCE protein because of mutations in both alleles of the RHCE gene. At present, little is known of the effect this has on the normal function of erythrocytes. In this study a group of five families belonging to a nomadic tribe in Malaysia were identified as carriers of the D-- haplotype. Analysis of homozygous individuals' genomic DNA showed two separate novel mutations. In four of the families, RHCE exons 1, 9 and 10 were present, while the 5th family possessed RHCE exons 1-3 and 10. Analysis of cDNA revealed hybrid transcripts, suggesting a gene conversion event with RHD, consistent with previously reported D-- mutations. Immunoblotting analysis of D-- erythrocyte membrane proteins found that Rh-associated glycoprotein (RHAG) migrates with altered electrophoretic mobility on sodium dodecyl sulphate polyacrylamide gel electrophoresis, consistent with increased glycosylation. Total amounts of Rh polypeptide in D-- membranes were comparable with controls, indicating that the exalted D antigen displayed by D-- red cells may be associated with altered surface epitope presentation. The adhesion molecules CD44 and CD47 are significantly reduced in D--. Together these results suggest that absence of RHCE polypeptide alters the structure and packing of the band 3/Rh macrocomplex.
Related Terms
    Try searching for something
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links