Displaying publications 81 - 100 of 131 in total

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  1. Fulltext Exploring faradaic and non-faradaic electrochemical impedance spectroscopy approaches in Parkinson's disease diagnosis
    Adam H, Gopinath SCB, Adam T, A Fakhri M, T Salim E, Subramaniam S
    Heliyon, 2024 Mar 15;10(5):e27433.
    PMID: 38495156 DOI: 10.1016/j.heliyon.2024.e27433
    Parkinson's disease is a neurodegenerative condition defined by the progressive death of dopaminergic neurons in the brain. The diagnosis of Parkinson's disease often uses time-consuming clinical evaluations and subjective assessments. Electrochemical Impedance Spectroscopy (EIS) is a useful technique for electroanalytical devices due to its label-free performance, in-situ measurements, and low cost. The development of reliable diagnostic tools for Parkinson's disease can be significantly enhanced by exploring novel techniques like faradaic and non-faradaic EIS detection methods. These techniques have the ability to identify specific biomarkers or changes in electrochemical properties linked to Parkinson's disease, allowing for an early and accurate diagnosis. Faradaic EIS detection methods utilize redox processes on the electrode surface, while non-faradaic EIS methods rely on charge transfer or capacitive properties. EIS can identify biomarkers or changes in electrical properties as indicators of Parkinson's disease by measuring impedance at different frequencies. By combining both faradaic and non-faradaic EIS approaches, it may be possible to obtain a comprehensive understanding of the electrochemical changes occurring in Parkinson's disease patients. This may lead to the development of more effective diagnostic techniques and potentially opening up new avenues for personalized treatment strategies. This review explores the current research on faradaic and non-faradaic EIS approaches for diagnosing Parkinson's disease using electrochemical impedance spectroscopy.
  2. Evaluation of illness perceptions and their associations with glycaemic control, medication adherence and chronic kidney disease in type 2 diabetes mellitus patients in Malaysia
    Balasubramaniam S, Lim SL, Goh LH, Subramaniam S, Tangiisuran B
    Diabetes Metab Syndr, 2019 07 09;13(4):2585-2591.
    PMID: 31405680 DOI: 10.1016/j.dsx.2019.07.011
    BACKGROUND: Illness perceptions (IP) involve coping strategies and behavioural responses that can influence glycaemic control. Despite the importance of good glycaemic control, the majority of patients in Asia are not achieving glycaemic targets. An evaluation of IP in association with glycaemic control, medication adherence and chronic kidney disease (CKD) in Type 2 diabetes mellitus patients (T2DM) was carried out in an outpatient setting in Malaysia METHOD: A cross-sectional study was conducted using the Revised Illness Perception Questionnaire in a purposive sample of 384 T2DM patients.

    RESULTS: There were 55.7% females, median age was 58.2 years and median duration of diabetes was 13 years. The majority (79.4%) of patients had poor diabetes control (HbA1c ≥ 7.0%) and 39.6% of patients had low medication adherence. Patients with good glycaemic control had a higher Timeline Acute/Chronic and Emotional Representations score, hence they held the correct belief that diabetes is chronic and experienced negative emotions. Highly adherent patients had a higher Illness Coherence (χ2 = 21.385, p 

  3. Estimates of genetic parameters of certain characters in Hevea brasiliensis
    Tan H, Mukherjee TK, Subramaniam S
    Theor Appl Genet, 1975 Jan;46(4):181-90.
    PMID: 24419927 DOI: 10.1007/BF00281668
    Heritability estimates of five quantitative characters, namely, yield, girth, girth increment, virgin bark and renewed bark thickness, of the breeding Phase III Hevea families have been obtained by variance component analyses. In general, the combined heritability estimates for various characters were low to moderate. The heritabilities of these characters based on female variance components, however, were high, suggesting that considerable improvement of each of the characters could be achieved in properly designed experiments.Estimates of heritability for average yields (Range: 0.11-0.34) over different years showed that the first three years' yield was adequate for predicting estimates of genetic variance for the average of five years' yield.Correlation studies on yield with other characters indicated considerable influence of environment, with genetic correlations accounting for about 0.07 to 0.36 in the characters studied.Expected direct response to selection in yield and correlated response in yield to selection for girth at opening and virgin bark thickness have been calculated using three arbitrary values of selection intensity. The efficiency of the correlated response was found to be approximately half that of the direct response. However, the indirect selection for yield using virgin bark thickness appeared to be more favourable than that using the girth at opening favoured by earlier workers.
  4. Fulltext Endoscopic nasopharyngectomy: the Sarawak experience
    Rohaizam J, Subramaniam SK, Vikneswaran T, Tan VE, Tan TY
    Med J Malaysia, 2009 Sep;64(3):213-5.
    PMID: 20527270 MyJurnal
    Shifting the paradigm of treatment of a locally recurrent nasopharyngeal carcinoma (NPC) from the non-surgical management to a surgical modality has always been a challenge. However, many studies on endoscopic nasopharyngectomy have proven it to be a reliable form of treatment with an excellent outcome. Since 2007, in Sarawak General Hospital, six cases of endoscopic nasopharyngectomy for locally recurrent NPC have been performed with encouraging results.
  5. Effects of salt and heat pre-treatment factors on efficient regeneration in barley (Hordeum vulgare L.)
    Haque M, Islam SMS, Subramaniam S
    3 Biotech, 2017 May;7(1):63.
    PMID: 28452013 DOI: 10.1007/s13205-017-0675-z
    An efficient callus induction and plant regeneration system has been developed using salt and heat as pre-treatment factors for three barley genotypes viz. BB-3, BB-6 and BHL-18. Different concentrations of NaCl (1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 g/L) were used and its effects were determined on the basis of the viability of callus (CV), plant regeneration (PR), relative growth rate (RGR) and tolerance index (TI). The BB-6 showed highest performance on tolerance based on CV (14.72%), PR (7.69%), RGR (0.91%) and TI (0.42%) at 6.5 g/L NaCl. Various NaCl concentrations displayed significantly differences at P 
  6. Effects of fusaric acid treatment on the protocorm-like bodies of Dendrobium sonia-28
    Dehgahi R, Zakaria L, Mohamad A, Joniyas A, Subramaniam S
    Protoplasma, 2016 Sep;253(5):1373-83.
    PMID: 26471909 DOI: 10.1007/s00709-015-0895-1
    Dendrobium sonia-28 is a popular orchid hybrid due to its flowering recurrence and dense inflorescences. Unfortunately, it is being decimated by fungal diseases, especially those caused by Fusarium proliferatum. In this study, selection of F. proliferatum-tolerant protocorm-like bodies (PLBs) was carried out by assessing the effects of differing concentrations of fusaric acid (FA). PLBs were cultured on Murashige and Skoog (MS) medium supplemented with 0.05 to 0.2 millimolar (mM) concentrations of FA. Higher concentrations of FA increased mortality of PLBs and reduced their growth. The survival rate for 0.05 mM FA was 20 % but only 1 % at the highest dose of 0.2 mM. Additionally, two different size ranges of PLBs were investigated, and growth increased more at lower FA concentrations for larger PLBs, whilst the growth rate of smaller PLBs was inhibited at an FA concentration of 0.2 mM. Histological examination using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses disclosed severe cell wall and organelle damage, as well as stomatal closure in PLBs treated with the high FA concentrations. Reductions in plantlet growth were much greater at the highest concentrations of FA. Some randomly amplified polymorphic DNA (RAPD) markers clearly discriminated between selected and non-selected variants of Dendrobium sonia-28, showing different banding patterns for each FA concentration and specific bands for selected and control plants.
  7. Fulltext Effects of droplet-vitrification cryopreservation based on physiological and antioxidant enzyme activities of Brassidium shooting star orchid
    Rahmah S, Ahmad Mubbarakh S, Soo Ping K, Subramaniam S
    ScientificWorldJournal, 2015;2015:961793.
    PMID: 25861687 DOI: 10.1155/2015/961793
    Protocorm-like bodies (PLBs) of Brassidium Shooting Star orchid were successfully cryopreserved using droplet-vitrification method. Vitrification based cryopreservation protocol is comprised of preculture, osmoprotection, cryoprotection, cooling, rewarming, and growth recovery and each and every step contributes to the achievement of successful cryopreservation. In order to reveal the lethal and nonlethal damage produced by cryopreservation, histological observation, scanning electron microscopy (SEM), and biochemical analysis were carried out in both cryopreserved and noncryopreserved PLBs of Brassidium Shooting Star orchid comparing with the control PLBs stock culture. Histological and scanning electron microscopy analyses displayed structural changes in cryopreserved PLBs due to the impact of cryoinjury during exposure to liquid nitrogen. Total soluble protein significantly increased throughout the dehydration process and the highest value was achieved when PLBs were stored in liquid nitrogen. Ascorbate peroxidase (APX) and catalase (CAT) showed the highest enzyme activities in both dehydration and cryostorage treatments indicating that stress level of PLBs was high during these stages.
  8. Effects of ascorbic acid on PVS2 cryopreservation of Dendrobium Bobby Messina's PLBs supported with SEM analysis
    Antony JJ, Keng CL, Mahmood M, Subramaniam S
    Appl Biochem Biotechnol, 2013 Sep;171(2):315-29.
    PMID: 23832189 DOI: 10.1007/s12010-013-0369-x
    Regrowth of the cryopreserved protocorm-like bodies (PLBs) of Dendrobium Bobby Messina was assessed based on the plant vitrification solution 2 (PVS2) optimisation conditions. The optimized protocol obtained based on TTC spectrophotometrical analysis and growth recovery were 3-4 mm of PLBs size precultured in 0.2 M sucrose for 1 day, treated with a mixture of 2 M glycerol and 0.4 M sucrose supplemented with half-strength liquid MS media at 25 °C for 20 min and subsequently dehydrated with PVS2 at 0 °C for 20 min prior to storage in liquid nitrogen. Following rapid warming in a water bath at 40 °C for 90 s, PLBs were treated with unloading solution containing half-strength liquid MS media supplemented with 1.2 M sucrose. Subsequently, the PLBs were cultured on half-strength semi-solid MS media supplemented with 2 % (w/v) sucrose without any growth regulators and resulted in 40 % growth recovery. In addition, ascorbic acid treatment was used to evaluate the regeneration process of cryopreserved PLBs. However, growth recovery rates of non-cryopreserved and cryopreserved PLBs were 30 and 10 % when 0.6 mM ascorbic acid was added. Scanning electron microscopy analysis indicates that there are not much damages observed on both cryopreserved and non-cryopreserved PLBs in comparison to PLBs stock culture.
  9. Effect of plasmolysis on protocorm-like bodies of Dendrobium Bobby Messina orchid following cryopreservation with encapsulation-dehydration method
    Antony JJ, Mubbarakh SA, Mahmood M, Subramaniam S
    Appl Biochem Biotechnol, 2014 Feb;172(3):1433-44.
    PMID: 24218184 DOI: 10.1007/s12010-013-0636-x
    Histological observation and scanning electron microscopy analyses in Dendrobium Bobby Messina indicates the cellular process of cryopreserved protocorm-like bodies (PLBs) was different comparative to non-cryopreserved PLBs. The cellular process was not only modified by the freezing and thawing effect but also due to the dehydration process itself during the cryopreservation procedure. Histological observation in Dendrobium Bobby Messina in encapsulation-dehydration method indicated that the degree of plasmolysis causes more cellular changes to the cryopreserved PLBs comparative to non-cryopreserved and stock culture PLBs. These results revealed higher amount of homogenous cell population and denser cytoplasm in cryopreserved PLBs. Histological analysis also revealed more voluminous nucleus in cryopreserved PLBs comparative to non-cryopreserved PLBs and PLBs stock culture. In contrast, scanning electron microscope analysis showed severe damages in cryopreserved PLBs and non-cryopreserved PLBs comparative to the PLBs stock culture which in return could be the possible reason of no regrowth in encapsulation-dehydration method. Damages incurred were on top part, side part, and at the stomata of the PLBs. Histological observation and scanning electron microscopy analyses in Dendrobium Bobby Messina indicates that the degree of plasmolysis causes changes in the cellular process of PLBs from cryopreserved PLBs was different comparative to non-cryopreserved PLBs.
  10. Effect of graphene oxide nanoparticles on in vitro growth of Fragaria x ananassa (Cameron Highlands white Strawberry) and evaluation of genetic stability using DAMD and ISSR markers
    Pang WQ, Lai CS, Mad' Atari MF, Pandian BR, Mohamad Ibrahim MN, Tan ST, et al.
    Plant Physiol Biochem, 2023 Nov;204:108104.
    PMID: 37862933 DOI: 10.1016/j.plaphy.2023.108104
    Graphene oxide (GO) is a novel nanomaterial with distinct physical properties and significant biological applications. The use of GO in plant tissue culture offers several new properties and potential applications. This research is vital due to the growing need for innovative techniques to promote plant growth, improve plant productivity and mitigate challenges posed by environmental stressors. This study focused on the rare Cameron Highlands white strawberry plants (Fragaria x ananassa) and addressed issues such as callus production during direct shoot induction and hyperhydricity. The research aimed to investigate the effects of GO on the regeneration process and genetic stability of white strawberry plants and to use molecular markers to ensure that plants propagated in vitro are true to type. For this purpose, shoot tip explants were used and different concentrations of GO (0, 2.5, 5.0, 7.5, 10 mg/L) were added to the Murashige and Skoog (MS) medium for six weeks. The results showed that the optimum concentration for promoting the development of white strawberry seedlings was 7.5 mg/L of GO. The study also revealed that the addition of 7.5 mg/L GO in combination with 8 μM TDZ to the MS medium facilitated the induction of multiple shoots. Moreover, the clonal fidelity of the in vitro plants treated with GO showed a genetic similarity of over 97%. These results confirm that lower GO concentrations improve plant development and stability. Consequently, this nanomaterial has a positive effect on the growth of strawberry plants and is therefore well suited for strawberry tissue culture.
  11. Fulltext Effect of aflatoxin B1 exposure on the progression of depressive-like behavior in rats
    Subramaniam S, Sabran MR, Stanslas J, Kirby BP
    Front Nutr, 2022;9:1032810.
    PMID: 36466381 DOI: 10.3389/fnut.2022.1032810
    While it is well documented that aflatoxin B1 (AFB1); one of the most toxic food contaminants is linked to the development of depression. However, the mechanism on how it affects the gut and brain health leading to depressive-like behavior remains unclear. This study was conducted to determine the effect of AFB1 on the progression of depressive-like behavior. Thirty-two (n = 32) male Sprague Dawley rats were randomly allocated into four groups: control, low-dose (5 μg AFB1/kg), high-dose (25 μg AFB1/kg) and positive control group; exposed on chronic unpredictable mild stress (CUMS). After 4 weeks of exposure, sucrose preference test (SPT) and force swim test (FST) were used to measure behavioral despair. Fecal samples were selectively cultured to profile the bacteria. Body weight and relative organs weights were compared among groups. AFB1 and CUMS caused reduction in body weight and food intake as well as increased relative weight of adrenal glands, liver, and brain. Rats in AFB1 and CUMS groups had suppressed sucrose preference and prolonged immobility time in FST, wherein this could indicate anhedonia. Besides, fecal count of Lactobacillus spp. was significantly low following AFB1 exposure, with increasing count of Bifidobacterium spp, in comparison to the control. Indeed, further biochemical analysis and metagenomic approach are warranted to explore the underlying mechanisms on the role of gut microbiota dysbiosis and dysregulation of gut-brain axis due to AFB1 neurotoxicity on the progression of depressive-like behavior.
  12. Fulltext Effect of a Screening and Education Programme on Knowledge, Beliefs, and Practices Regarding Osteoporosis among Malaysians
    Chan CY, Subramaniam S, Chin KY, Ima-Nirwana S, Muhammad N, Fairus A, et al.
    Int J Environ Res Public Health, 2022 May 17;19(10).
    PMID: 35627609 DOI: 10.3390/ijerph19106072
    Background: Osteoporosis is an emerging geriatric condition with high morbidity and healthcare cost in developing nations experiencing rapid population ageing. Thus, identifying strategies to prevent osteoporosis is critical in safeguarding skeletal health. This study aimed to evaluate the effects of a bone health screening and education programme on knowledge, beliefs, and practice regarding osteoporosis among Malaysians aged 40 years and above. Methods: A longitudinal study was conducted from April 2018 to August 2019. During the first phase of the study, 400 Malaysians (190 men, 210 women) aged ≥ 40 years were recruited in Klang Valley, Malaysia. Information on subjects’ demography, medical history, knowledge, and beliefs regarding osteoporosis, physical activity status, and dietary and lifestyle practices were obtained. Subjects also underwent body anthropometry measurement and bone mineral density scan (hip and lumbar spine) using a dual-energy X-ray absorptiometry device. Six months after the first screening, similar investigations were carried out on the subjects. Results: During the follow-up session, 72 subjects were lost to follow up. Most of them were younger subjects with a lower awareness of healthy practices. A significant increase in knowledge, beliefs (p < 0.05), calcium supplement intake (p < 0.001), and dietary calcium intake (p = 0.036) and a reduction in coffee intake (p < 0.001) were found among subjects who attended the follow-up. In this study, the percentage of successful referrals was 41.86%. Subjects with osteoporosis were mostly prescribed alendronate plus vitamin D3 by medical doctors, and they followed the prescribed treatment accordingly. Conclusions: The bone health screening and education programmes in this study are effective in changing knowledge, beliefs, and practice regarding osteoporosis. The information is pertinent to policymakers in planning strategies to prevent osteoporosis and its associated problems among the middle-aged and elderly population in Malaysia. Nevertheless, a more comprehensive bone health education program that includes long-term monitoring and consultation is needed to halt the progression of bone loss.
  13. Fulltext Eagle's syndrome
    Subramaniam S, Abd Majid MD
    Med J Malaysia, 2003 Mar;58(1):139-41.
    PMID: 14556342
    Eagle's syndrome is an uncommon condition resulting from an elongated styloid process, which causes cervico facial pain, tinnitus and otalgia. A 48-year-old female presented to the clinic with bilateral upper neck pain radiating to the ears with tinnitus for almost one-year duration. Examination of the oral cavity revealed atrophic tonsils and palpable bony projection deep in the tonsillar fossa. Plain lateral neck X-ray and CT scan confirmed the presence of bilateral elongated styloid processes, which were subsequently resected surgically through an oropharyngeal approach. The patient was asymptomatic at follow up at 2 years.
  14. Fulltext Droplet-vitrification of Aranda Broga Blue orchid: Role of ascorbic acid on the antioxidant system and genetic fidelity assessments via RAPD and SCoT markers
    Khor SP, Yeow LC, Poobathy R, Zakaria R, Chew BL, Subramaniam S
    Biotechnol Rep (Amst), 2020 Jun;26:e00448.
    PMID: 32368510 DOI: 10.1016/j.btre.2020.e00448
    A droplet-vitrification cryopreservation protocol has been successfully developed for Aranda Broga Blue orchid hybrid using protocorm-like bodies (PLBs). However, maximum growth regeneration percentage was recorded at 5% only based on previous report. Thus, to improve growth recovery of cryopreserved PLBs, cryopreservation stages were supplemented with ascorbic acid, tested at 50, 100 and 150 mg/L. However, results demonstrated that exogenous ascorbic acid was not favorable in regeneration of cryopreserved explants (maximum value of 1.67 % with 50 mg/L ascorbic acid supplementation). Total soluble protein and various antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) were evaluated after each cryopreservation stages in conjunction with the application of exogenous ascorbic acid. Addition of antioxidant must be carefully evaluated and its application may not guarantee successful growth recovery. RAPD and SCoT molecular analysis confirmed the genetic stability of regenerated cryopreserved PLBs as no polymorphism was detected compared to control PLBs culture.
  15. Development of a PVS2 droplet-vitrification cryopreservation technique for Aranda Broga Blue orchid protocorm-like bodies (PLBs)
    Ping KS, Poobathy RR, Zakaria R, Subramaniam S
    Cryo Letters, 2018 5 8;38(4):290-298.
    PMID: 29734430
    　　BACKGROUND: Conservation of commercially important ornamental plants is important to maintain its unique beauty to cater the market demands.

    OBJECTIVE: The main objective is to develop an efficient cryopreservation technique for Aranda Broga Blue orchid PLBs using droplet-vitrification method.

    MATERIALS AND METHODS: Several critical factors in cryopreservation were accessed such as preculture concentrations and durations, choice of vitrification solutions, two-step or three-step vitrification, growth recovery medium and PVS2 exposure duration.

    RESULTS: The best growth regeneration percentage (5%) was obtained when 3-4mm PLBs were precultured in 0.2M sucrose for 3 days, followed by osmoprotection for 20 minutes, dehydration in PVS2 for 20 minutes at 0 degree C, LN storage, thawed and unloading for 20 minutes, and growth regeneration in VW10 medium. PLBs were found to be very sensitive to osmotic stress imposed by high molecular weight cryoprotectant such as sucrose and glycerol. Osmotic potential of growth recovery medium is one of the main factors that affect growth recovery in cryopreserved PLBs.

    CONCLUSION: Current report showed possibilities in cryopreserving Aranda Broga Blue PLBs using droplet-vitrification technique. However, further improvement of growth recovery can be done by focussing on approaches that facilitate sufficient water removal from PLBs without causing severe osmotic injuries to the plant cells.

  16. Fulltext Development of Osteoporosis Screening Algorithm for Population Aged 50 Years and above in Klang Valley, Malaysia
    Subramaniam S, Chan CY, Soelaiman IN, Mohamed N, Muhammad N, Ahmad F, et al.
    Int J Environ Res Public Health, 2020 04 07;17(7).
    PMID: 32272697 DOI: 10.3390/ijerph17072526
    Background: The current osteoporosis screening instruments are not optimized to be used among the Malaysian population. This study aimed to develop an osteoporosis screening algorithm based on risk factors for Malaysians. Methods: Malaysians aged ≥50 years (n = 607) from Klang Valley, Malaysia were interviewed and their bone health status was assessed using a dual-energy X-ray absorptiometry device. The algorithm was constructed based on osteoporosis risk factors using multivariate logistic regression and its performance was assessed using receiver operating characteristics analysis. Results: Increased age, reduced body weight and being less physically active significantly predicted osteoporosis in men, while in women, increased age, lower body weight and low-income status significantly predicted osteoporosis. These factors were included in the final algorithm and the optimal cut-offs to identify subjects with osteoporosis was 0.00120 for men [sensitivity 73.3% (95% confidence interval (CI) = 54.1%-87.7%), specificity 67.8% (95% CI = 62.7%-85.5%), area under curve (AUC) 0.705 (95% CI = 0.608-0.803), p < 0.001] and 0.161 for women [sensitivity 75.4% (95% CI = 61.9%-73.3%), specificity 74.5% (95% CI = 68.5%-79.8%), AUC 0.749 (95% CI = 0.679-0.820), p < 0.001]. Conclusion: The new algorithm performed satisfactorily in identifying the risk of osteoporosis among the Malaysian population ≥50 years. Further validation studies are required before applying this algorithm for screening of osteoporosis in public.
  17. Fulltext Cytomegalovirus retinitis associated with high CD4 counts and DHEA abuse
    Keat GY, Ahmad SS, Subramaniam S, Ghani SA, Samsudin A
    Indian J Sex Transm Dis AIDS, 2020 06 18;41(1):119-122.
    PMID: 33062999 DOI: 10.4103/ijstd.IJSTD_90_15
    The most frequent ocular manifestation of acquired immunodeficiency syndrome (AIDS) is cytomegalovirus retinitis (CMVR). This infection is reportedly inversely proportional to the CD4 counts. Usually CMVR develops once the CD4 counts fall below 50/mm3. Our case report documents an AIDS patient who developed CMVR despite CD4 counts being persistently >200/mm3. The patient was self-administering dehydroepiandrosterone, high dose Vitamin C, testosterone and hydrocortisone. This case report describes a unique case of pharmacologically induced elevated CD4 counts, which however, did not prevent the development of CMVR in the patient.
  18. Fulltext Cryopreservation of oil palm (Elaeis guineensis Jacq.) polyembryoids via encapsulation-desiccation
    Palanyandy SR, Gantait S, Subramaniam S, Sinniah UR
    3 Biotech, 2020 Jan;10(1):9.
    PMID: 31850156 DOI: 10.1007/s13205-019-1997-9
    The current report assesses the efficiency of encapsulation-desiccation protocol to cryopreserve oil palm (Elaeis guineensis Jacq.) polyembryoids. Specifically identified polyembryoids, comprising of haustorium and torpedo-shaped structures, were encapsulated [comprising 3% (w/v) sodium alginate and 100 mM CaCl2]. Calcium alginate-encapsulated and sucrose-precultured polyembryoids were subjected to different spans of desiccation in a laminar air-flow cabinet, followed by freezing in liquid nitrogen. The effect of sucrose preculture (with gradual exposure to 0.3, 0.5, 0.75 and 1 M for 7 days) and dehydration periods (0-10 h) under sterile air-flow on post-freezing survival and regrowth of encapsulated polyembryoids were studied. Cryopreserved and thawed polyembryoids (initially precultured in sucrose, followed by 9 h air-desiccated to 23.3% moisture content) displayed the highest survival percentage (73.3%) and regeneration (of shoot, root and secondary somatic embryo) on Murashige and Skoog regrowth medium containing sucrose (0.3-1 M) and 0.2 mg/l 2,4-dichlorophenoxy acetic acid. In addition, ultrastructural study using scanning electron microscopy exhibited successful revival of cryopreserved polyembryoids, owing to retention of cellular membrane stability through optimized and protected (encapsulated) desiccation. The present study thus substantiates the potential of this encapsulation-desiccation procedure in cryopreservation of oil palm polyembryoids for long-term conservation programs.
  19. Cryopreservation of Brassidium Shooting Star orchid using the PVS3 method supported with preliminary histological analysis
    Mubbarakh SA, Rahmah S, Rahman ZA, Sah NN, Subramaniam S
    Appl Biochem Biotechnol, 2014 Jan;172(2):1131-45.
    PMID: 24146369 DOI: 10.1007/s12010-013-0597-0
    Cryopreservation is an alternative, safe, and cost-effective method for long-term plant genetic resource conservation. This study was conducted to optimize the conditions for cryopreserving the protocorm-like bodies (PLBs) of Brassidium Shooting Star orchid with the PVS3 vitrification method. Five parameters were assessed in this study: PLB size, sucrose concentration, preculture duration, PVS3 duration, and unloading duration. The viability of the cryopreserved PLBs was determined using the triphenytetrazolium chloride assay and growth recovery assessments. The optimum condition for the cryopreservation of the PLBs of Brassidium Shooting Star orchid is based on the size range between 3 and 4 mm precultured with half-strength semi-solid MS media supplemented with 0.25 M sucrose for 24 h, followed by treatment with loading solution mixture of 2 M glycerol and 0.4 M sucrose supplemented with half-strength liquid MS media at 25 °C for 20 min. The PLBs were then dehydrated with PVS3 at 0 °C for 20 min prior to immersion in liquid nitrogen; finally, the PLBs were immersed with half-strength liquid MS media supplemented with 1.2 M sucrose for 30 min. Histological analyses displayed denser cytoplasm and voluminous nucleus in the cryopreserved PLBs of Brassidium Shooting Star orchid.
  20. Fulltext Comparison of HIV antibody profiles in intravenous drug users and individuals infected by the sexual route
    Subramaniam S, Balasubramaniam V, Sinniah M, Thayan R, Lim LY
    Malays J Pathol, 1993 Dec;15(2):143-6.
    PMID: 8065176
    HIV-1 antibody patterns in two groups, those infected by the intravenous route (IV drug users) and those infected by the sexual route (prostitutes, male homosexuals and sexually transmitted disease patients) were compared using the Western blot technique. A total of 160 cases were studied. The intravenous drug user (IVDU) group appeared to respond to fewer antibody markers than the sexually infected group, the difference being significant for markers p31, p51, p55, p66, gp41 and gp120. Furthermore, a higher proportion (63%) of the sexually infected group carried antibodies to all Western blot markers as compared to the IVDU group (49%).
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