Displaying publications 1 - 20 of 22 in total

  1. Ramalingam S, Sinniah B, Krishnan U
    Am J Trop Med Hyg, 1983 Sep;32(5):984-9.
    PMID: 6625078
    Albendazole, a new anthelmintic drug was evaluated in Malaysia in 91 patients, with single or mixed infections of Ascaris, Trichuris, and hookworm. Albendazole was administered as a single dose of 400 mg, 600 mg, or 800 mg. The cure rate for Ascaris at all three doses was 100% at days 14 and 21 post-treatment; for hookworm it was 98.8%, 100% and 98%, respectively, at day 14 and 68.8%, 100% and 84%, respectively, at day 21; for Trichuris it was 31.2%, 57.1% and 42.3%, respectively, at day 14 and 27.3%, 60.9% and 48.0%, respectively, at day 21. The egg reduction rate at day 21 was 100% at all three doses for Ascaris, 94.5%, 100% and 96.1%, respectively, for hookworm; and 39.2%, 85.1% and 72.8%, respectively, for Trichuris. There were no side effects, and biochemical examination of blood and urine did not indicate any unfavourable changes. Based on this trial, the recommended dosage for Ascaris and hookworm is a 400 mg single dose, and for Trichuris is a 600 mg single dose. Albendazole appears to be more effective than other available anthelmintic drugs.
  2. Ramalingam S, Nurulhuda A, Bee LH
    PMID: 7444582
    A case of urogenital myiasis caused by Chrysomya bezziana (Diptera: Calliphoridae) was diagnosed in a 76-year old patient who had carcinoma of the rectum. A total of 35 larvae were obtained from ulcers near the external genitalia and urethra opening. Larvae pupated within 1 to 2 days and 6 days later emerged as adult males. These were identified as Chrysomya bezziana. Female flies possibly attracted by the fetid odour, laid eggs in the existing lesions in the urogenital area, the larvae invading and feeding on living tissue. Lack of personal hygiene was the contributing factor for the cause of urogenital myiasis in this patient.
  3. Nathan PS, Ramalingam S, Jegathesan M
    Med J Malaysia, 1977 Sep;32(1):82-4.
    PMID: 345072
  4. Ramachandran CP, Ramalingam S, Chelvam MP
    Med J Malaya, 1966 Jun;20(4):338-9.
    PMID: 4224564
  5. 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.
  6. Dissanaike AS, Ramalingam S, Fong A, Pathmayokan S, Thomas V, Kan SP
    Am J Trop Med Hyg, 1977 Nov;26(6 Pt 1):1143-7.
    PMID: 596511
    An active worm was seen in the right eye of a 62-year-old man in Malaysia. The worm was behind the lens and attached at one end to some vitreous fibers. It was tentatively identified as an immature Dirofilaria immitis. There appear to be only five previous authentic reports of filariae in the vitreous.
  7. Mohd S, Ghazali MI, Yusof N, Sulaiman S, Ramalingam S, Kamarul T, et al.
    Cell Tissue Bank, 2018 Dec;19(4):613-622.
    PMID: 30056604 DOI: 10.1007/s10561-018-9711-4
    Air-dried and sterilized amnion has been widely used as a dressing to treat burn and partial thickness wounds. Sterilisation at the standard dose of 25 kGy was reported to cause changes in the morphological structure as observed under the scanning electron microscope. This study aimed to quantify the changes in the ultrastructure of the air-dried amnion after gamma-irradiated at several doses by using atomic force microscope. Human placentae were retrieved from mothers who had undergone cesarean elective surgery. Amnion separated from chorion was processed and air-dried for 16 h. It was cut into 10 × 10 mm, individually packed and exposed to gamma irradiation at 5, 15, 25 and 35 kGy. Changes in the ultrastructural images of the amnion were quantified in term of diameter of the epithelial cells, size of the intercellular gap and membrane surface roughness. The longest diameter of the amnion cells reduced significantly after radiation (p 
  8. Singh VA, Ramalingam S, Haseeb A, Yasin NFB
    J Orthop Surg (Hong Kong), 2020 7 23;28(2):2309499020941659.
    PMID: 32696708 DOI: 10.1177/2309499020941659
    INTRODUCTION: Limb length discrepancy (LLD) of lower extremities is underdiagnosed due to compensatory mechanisms during locomotion. The natural course of compensation leads to biomechanical alteration in human musculoskeletal system leading to adverse effects. General consensus accepts LLD more than 2 cm as significant to cause biomechanical alteration. No studies were conducted correlating height and lower extremities true length (TL) to signify LLD. Examining significant LLD in relation to height and TL using dynamic gait analysis with primary focus on kinematics and secondary focus on kinetics would provide an objective evaluation method.

    METHODOLOGY: Forty participants with no evidence of LLD were recruited. Height and TL were measured. Reflective markers were attached at specific points in lower extremity and subjects walked in gait lab at a self-selected normal walking pace with artificial LLDs of 0, 1, 2, 3, and 4 cm simulated using shoe raise. Accommodation period of 30 min was given. Infrared cameras were used to capture the motion. Primary kinematic (knee flexion and pelvic obliquity (PO)) and secondary kinetic (ground reaction force (GRF)) were measured at right heel strike and left heel strike. Functional adaptation was analyzed and the postulated predictor indices (PIs) were used as a screening tool using height, LLD, and TL to notify significance.

    RESULTS: There was a significant knee flexion component seen in height category of less than 170 cm. There was significant difference between LLD 3 cm and 4 cm. No significant changes were seen in PO and GRF. PIs of LLD/height and LLD/TL were analyzed using receiver operating characteristic curve. LLD/height as a PI with value of 1.75 was determined with specificity of 80% and sensitivity of 76%.

    CONCLUSION: A height of less than 170 cm has significant changes in relation to LLD. PI using LLD/height appears to be a promising tool to identify patients at risk.

  9. 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.
  10. Raj JJ, Kow RY, Ramalingam S, Low CL
    Cureus, 2021 Jul;13(7):e16155.
    PMID: 34367767 DOI: 10.7759/cureus.16155
    Secondary hyperparathyroidism is a complication arising from untreated end-stage renal disease (ESRD). It can invariably lead to osteoporosis and subsequently cause pathological neck of femur (NOF) fracture. Despite being young, osteosynthesis in neck of femur fractures of these patients often leads to nonunion and implant failure due to severely osteoporotic bone. We present our experience in managing three young patients with ESRD and secondary hyperthyroidism who sustained NOF fractures. All three patients were successfully treated and showed no complication at one year post-operation. Based on our experience and literature review, we propose a simple algorithm to guide the management of these patients.
  11. 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.
  12. Mohd S, Samsuddin SM, Ramalingam S, Min NW, Yusof N, Zaman TK, et al.
    Cell Tissue Bank, 2015 Dec;16(4):523-30.
    PMID: 25656787 DOI: 10.1007/s10561-015-9499-4
    The main advantage of establishing in-house bone banks is its ability to readily provide allograft bones for local surgeries. Bone procurement activities of our university bone bank during the 10 years of operation were reviewed. Socio-demographic data of donors, types of bone procured, cases of rejected bones and types of allograft bones transplanted are presented. From 179 potential donors, 73 % were accepted with 213 procured bones. Femoral head was the common bone transplanted (45 %), as it was also the most common procured (82 %). Bones were rejected mainly due to non-technical reasons (83 %) rather than positive results of microbiological (13 %) and serological (4 %) tests. Comprehensive data could not be obtained for further analysis due to difficulties in retrieving information. Therefore, quality assurance system was improved to establish more systematic documentations, as the basis of good banking practice with process control hence allowing traceability.
  13. 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.

  14. Ariffin AF, Yusof N, Mohd S, Rahman SA, Ramalingam S, Mansor A, et al.
    Cell Tissue Bank, 2019 Dec;20(4):527-534.
    PMID: 31456097 DOI: 10.1007/s10561-019-09785-4
    Calcium contents of demineralised human cortical bone determined by titrimetric assay and atomic absorption spectrophotometry technique were verified by comparing to neutron activation analysis which has high recovery of more than 90%. Conversion factors determined from the comparison is necessary to correct the calcium content for each technique. Femurs from cadaveric donors were cut into cortical rings and demineralised in 0.5 M hydrochloric acid for varying immersion times. Initial calcium content in the cortical bone measured by titration was 4.57%, only 21% of the measurement by neutron activation analysis; while measured by atomic absorption spectrophotometer was 13.4%, only 61% of neutron activation analysis. By comparing more readings with the measurements by neutron activation analysis with 93% recovery, a conversion factor of 4.83 was verified and applied for the readings by titration and 1.45 for atomic absorption spectrophotometer in calculating the correct calcium contents. The residual calcium content started to reduce after the cortical bone was demineralised in hydrochloric acid for 8 h and reduced to 13% after 24 h. Using the linear relationship, the residual calcium content could be reduced to less than 8% after immersion in hydrochloric acid for 40 h. Atomic absorption spectrophotometry technique is the method of choice for calcium content determination as it is more reliable compared to titrimetric assay.
  15. Yang Harmony TC, Yusof N, Ramalingam S, Baharin R, Syahrom A, Mansor A
    Clin Orthop Relat Res, 2022 02 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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