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Field's stain--a rapid staining method for Acanthamoeba spp

Pirehma M, Suresh K, Sivanandam S, Anuar AK, Ramakrishnan K, Kumar GS

Parasitol Res, 1999 Oct;85(10):791-3.
PMID: 10494803

Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba sp. using the modified Field's staining technique. A. castellanii, which was used in the present experiment, is maintained in our laboratory in mycological peptone medium (Gibco). The cultures were pooled together and smears were made on glass slides for staining purposes. Different types of stains such as Field's stain, modified Field's stain, Wright's stain, Giemsa stain, Ziehl-Neelsen stain, and trichrome stain were used to determine the best stain for the identification of this amoeba. The concentration of various stains and the duration of staining were varied to provide the best color and contrast for each stain. Acanthamoeba was also obtained from the brain of experimentally infected mice and was stained with various stains as mentioned above to determine the best stain for use in identifying the presence of this parasite in experimentally infected animals. The modified Field's stain gives a very good color contrast as compared with other stains. Furthermore, it takes only 20 s to be carried out using the least number of reagents, making it suitable for both laboratory and field use.
Gelatin controversies in food, pharmaceuticals, and personal care products: Authentication methods, current status, and future challenges

Ali E, Sultana S, Hamid SBA, Hossain M, Yehya WA, Kader A, et al.

Crit Rev Food Sci Nutr, 2018 Jun 13;58(9):1495-1511.
PMID: 28033035 DOI: 10.1080/10408398.2016.1264361

Gelatin is a highly purified animal protein of pig, cow, and fish origins and is extensively used in food, pharmaceuticals, and personal care products. However, the acceptability of gelatin products greatly depends on the animal sources of the gelatin. Porcine and bovine gelatins have attractive features but limited acceptance because of religious prohibitions and potential zoonotic threats, whereas fish gelatin is welcomed in all religions and cultures. Thus, source authentication is a must for gelatin products but it is greatly challenging due to the breakdown of both protein and DNA biomarkers in processed gelatins. Therefore, several methods have been proposed for gelatin identification, but a comprehensive and systematic document that includes all of the techniques does not exist. This up-to-date review addresses this research gap and presents, in an accessible format, the major gelatin source authentication techniques, which are primarily nucleic acid and protein based. Instead of presenting these methods in paragraph form which needs much attention in reading, the major methods are schematically depicted, and their comparative features are tabulated. Future technologies are forecasted, and challenges are outlined. Overall, this review paper has the merit to serve as a reference guide for the production and application of gelatin in academia and industry and will act as a platform for the development of improved methods for gelatin authentication.
Genetic variability of Blastocystis sp. isolates obtained from cancer and HIV/AIDS patients

Tan TC, Ong SC, Suresh KG

Parasitol Res, 2009 Oct;105(5):1283-6.
PMID: 19603182 DOI: 10.1007/s00436-009-1551-5

This represents the first study to determine the genetic diversity of Blastocystis sp. among cancer and HIV/AIDS patients. Forty Blastocystis sp. isolates obtained from 20 cancer and 20 HIV/AIDS patients were genotyped by PCR using seven pairs of known sequenced-tagged site primers. Out of the 40 isolates, 38 were identified as one of the known genotypes and two isolates were negative with all the STS primers. Blastocystis sp. subtype 3 which is reported to be associated with disease was found to be predominant among the study subjects.
Fulltext Genotoxic effects of tobacco use in residents of hilly areas and foot hills of Western Ghats, Southern India

Chandirasekar R, Murugan K, Muralisankar T, Uthayakumar V, Jayakumar R, Mohan K, et al.

Sci Rep, 2019 Oct 17;9(1):14898.
PMID: 31624274 DOI: 10.1038/s41598-019-51275-w

Smoking and smokeless tobacco consumption is a significant risk factor that provokes genetic alterations. The present investigation was to evaluate the biomarkers of genotoxicity including micronucleus (MN), chromosome aberrations (CA) and DNA strand breaks among tobacco consumers and control individuals residing in hilly areas of Western Ghats, Tamilnadu, South India. This study included 268 tobacco consumers with equal number of controls. The tobacco consumers were divided into Group I (<10 years of tobacco consumption with an age range from 15 to 35 years) and group II (>10 years consumption above 35 years of age). Chromosome aberration (CA) and comet assay were performed using blood and micronucleus assay from exfoliated buccal epithelial cells obtained from tobacco consumers and controls. Elevated levels of CA were found in group II (Chromatid type: 2.39 ± 1.13 and chromosome type: 1.44 ± 1.24) exposed subjects, high micronucleus and DNA damage (TL:4.48 ± 1.24 and TM:3.40 ± 1.58) levels were significantly (p
Glycerol with fetal calf serum--a better cryoprotectant for Blastocystis hominis

Suresh K, Init I, Reuel PA, Rajah S, Lokman H, Khairul Anuar A

Parasitol Res, 1998;84(4):321-2.
PMID: 9569099
Fulltext Granular Formation during Apoptosis in Blastocystis sp. Exposed to Metronidazole (MTZ)

Dhurga DB, Suresh K, Tan TC

PLoS One, 2016;11(7):e0155390.
PMID: 27471855 DOI: 10.1371/journal.pone.0155390

The role and function of the granular life cycle stage in Blastocystis sp, remains uncertain despite suggestions being made that the granules are metabolic, reproductive and lipid in nature. This present study aims to understand granular formation by triggering apoptosis in Blastocystis sp. by treating them with metronidazole (MTZ). Blastocystis sp.cultures of 4 sub-types namely 1, 2, 3 and 5 when treated with 0.01 and 0.0001 mg/ml of metronidazole (MTZ) respectively showed many of the parasites to be both viable and apoptotic (VA). Treated subtype 3 isolates exhibited the highest number of granular forms i.e. 88% (p<0.001) (0.0001 mg/ml) and 69% (p<0.01) (0.01 mg/ml) respectively at the 72 h in in vitro culture compared to other subtypes. These VA forms showed distinct granules using acridine orange (AO) and 4',6-diamino-2-phenylindole (DAPI) staining with a mean per cell ranging from 5 in ST 5 to as high as 16 in ST 3. These forms showed intact mitochondria in both viable apoptotic (VA) and viable non-apoptotic (VNA) cells with a pattern of accumulation of lipid droplets corresponding to viable cells. Granular VA forms looked ultra-structurally different with prominent presence of mitochondria-like organelle (MLO) and a changed mitochondrial trans-membrane potential with thicker membrane and a highly convoluted inner membrane than the less dense non-viable apoptotic (NVA) cells. This suggests that granular formation during apoptosis is a self-regulatory mechanism to produce higher number of viable cells in response to treatment. This study directs the need to search novel chemotherapeutic approaches by incorporating these findings when developing drugs against the emerging Blastocystis sp. infections.
Fulltext Graphene-Gold Nanoparticles Hybrid-Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

Khalil I, Julkapli NM, Yehye WA, Basirun WJ, Bhargava SK

Materials (Basel), 2016 May 24;9(6).
PMID: 28773528 DOI: 10.3390/ma9060406

Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene-AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene-Au nanocomposites. The paper highlights the graphene-gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.
High levels of oxidative stress in rats infected with Blastocystis hominis

Chandramathi S, Suresh K, Shuba S, Mahmood A, Kuppusamy UR

Parasitology, 2010 Apr;137(4):605-11.
PMID: 19961647 DOI: 10.1017/S0031182009991351

Numerous studies have revealed the presence of oxidative stress in parasitic infections. However, such studies were lacking in the Malaysian population. Previously, we have provided evidence that oxidative stress is elevated in Malaysians infected with intestinal parasites. Stool examinations revealed that about 47.5% of them were infected with the polymorphic protozoa, Blastocystis hominis. However, they were found to have mixed infection with other intestinal parasites.
High-Sensitivity Cardiac Troponin I Levels in Normal and Hypertensive Pregnancy

Ravichandran J, Woon SY, Quek YS, Lim YC, Noor EM, Suresh K, et al.

Am J Med, 2019 03;132(3):362-366.
PMID: 30503877 DOI: 10.1016/j.amjmed.2018.11.017

PURPOSE: The purpose of this study was to examine the association of circulating concentrations of high-sensitivity cardiac troponin I (hs-cTn) in the various trimesters of pregnancy in patients with and without hypertension.
METHODS: This was a prospective cross-sectional study of pregnant and postnatal women aged between 18-35 years with no coexisting diseases. Serum samples were analysed for hs-TnI.
RESULTS: A total of 880 women (mean age = 29.1 years [standard deviation = 5.1 years]) were recruited with 129 (14%), 207 (24%), and 416 (47%) patients in the first, second, and third trimesters, respectively. Ninety (10%) participants were recruited in the postnatal period. During pregnancy 28 (3%) patients were classified as having pregnancy-induced hypertension and 10 (1%) as preeclampsia. High-sensitivity cardiac troponin I was measurable in 546 (62%) participants with a median of 1 ng/L (range 0 to 783 ng/L). Troponin concentrations were above the 99th percentile in 19 (2%) individuals. Patients with pregnancy-induced hypertension and preeclampsia had higher concentrations of hs-TnI (median 11 ng/L [interquartile range (IQR) 6 to 22 ng/L] vs 12ng/L [IQR 3 to 98 ng/L] vs 1 ng/L [IQR 0 to 1 ng/L]). In logistic regression modeling hs-cTnI concentration remained an independent predictor of pregnancy-induced hypertension or preeclampsia in both unadjusted and adjusted models (odds ratio 9.3 [95% confidence interval 5.8 to 16.3] and 11.5 [95% confidence interval 6.3 to 24.1], respectively, per doubling of hs-TnI concentrations).
CONCLUSIONS: Cardiac troponin measured using a high-sensitivity assay is quantifiable in the majority of young pregnant women with 2% of individuals having concentration above the 99th percentile sex-specific threshold. Patients with pregnancy-induced hypertension or preeclampsia had higher cardiac troponin concentrations. Cardiac troponin was a strong independent predictor of pregnancy-induced hypertension or preeclampsia in pregnant and postnatal women.
Fulltext Identification and characterisation of heat shock protein 70 in thermal stressed Blastocystis sp

Gaythri T, Suresh K, Subha B, Kalyani R

PLoS One, 2014;9(9):e95608.
PMID: 25180903 DOI: 10.1371/journal.pone.0095608

Protistan parasites in order to ensure their viability and demonstrate successful progression in their life cycle need to respond towards various environmental stressors. Blastocystis sp. is known to be the most commonly found intestinal protistan parasite in any human stool surveys and has been incriminated to be responsible for diarrhea and bloating stomach. The present study demonstrates for the first time the presence of HSP70 in subtypes of Blastocystis sp. when the cultures were subjected to temperature of 39 and 41 °C where the growth of parasites was reduced to a minimum to majority being granular forms. The growth of parasites exposed to higher temperatures however doubled compared to the controls when the parasites were re-cultured back at 37 °C. Upon thermal stress at 41 °C, subtype 3 and subtype 5 isolates' growth reached up to 2.97 × 10(6) and 3.05 × 10(6) cells/ml compared to their respective controlled culture tubes at 37 °C which peaked only at 1.34 × 10(6) and 1.70 × 10(6) cells/ml respectively. The designed primer set that amplified Blastocystis sp. subtype 7 HSP70 gene in subtypes 1, 3 and 5 was against a conserved region. The gene was amplified at 318 bp. The multiple sequence alignment showed that the targeted sequence length ranges from 291-295 bp. The pair wise alignment result showed that the sequence identity among the four sequence ranges from 88% to 96%. These findings were further evidenced by the up regulation of HSP70 gene in thermal stressed isolates of subtype 3 and 5 at 41 °C. Higher number of granular forms was significantly found in thermal stressed isolates of subtype 3 and 5 which implicates that this life cycle stage has a role in responding to thermal stress.
Fulltext Immune response in acute Toxoplasma infection of Balb/C, ICR and CBA/J mice

Suresh K, Mak JW, Yong HS

Southeast Asian J. Trop. Med. Public Health, 1991 Sep;22(3):452-4.
PMID: 1818401
Implementation of Oral Health Education to Orphan Children

Khedekar M, Suresh KV, Parkar MI, Malik N, Patil S, Taur S, et al.

J Coll Physicians Surg Pak, 2015 Dec;25(12):856-9.
PMID: 26691356 DOI: 12.2015/JCPSP.856859

To determine the knowledge and oral hygiene status of orphanage children in Pune and changes in them after health education.
In vitro and in vivo thermal stress induces proliferation of Blastocystis sp

Thergarajan G, Govind SK, Bhassu S

Parasitol Res, 2018 Jan;117(1):177-187.
PMID: 29188368 DOI: 10.1007/s00436-017-5688-3

Blastocystis sp. is known to be the most commonly found intestinal protozoan parasite in human fecal surveys and has been incriminated to cause diarrhea and abdominal bloating. Binary fission has been widely accepted as the plausible mode of reproduction for this parasite. The present study demonstrates that subjecting the parasites in vitro to higher temperature shows the proliferation of parasite numbers in cultures. Transmission electron microscopy was used to compare the morphology of Blastocystis sp. subtype 3 isolated from a dengue patient having high fever (in vivo thermal stress) and Blastocystis sp. 3 maintained at 41 °C (in vitro thermal stress) and 37 °C (control). Fluorescence stains like acridine orange (AO) and 4',6'-diamino-2-phenylindole (DAPI) were used to demonstrate the viability and nuclear content of the parasite for both the in vitro and in vivo thermal stress groups of parasites. Blastocystis sp. at 37 °C was found to be mostly vacuolar whereas the in vitro thermal stressed isolates at 41 °C were granular with electron dense material seen to protect the granules within the central body. Parasites of the in vivo thermal stressed group showed similar ultrastructure as the in vitro ones. AO and DAPI staining provided evidence that these granules are viable which develop into progenies of Blastocystis sp. These granular forms were then observed to rupture and release progenies from the mother cells whilst the peripheral cytoplasmic walls were seen to degrade. Upon exposure to high temperature both in vitro and in vivo, Blastocystis sp. in cultures show higher number of granular forms seen to be protected by the electron dense material within the central body possibly acting as a protective mechanism. This is possibly to ensure the ability to survive for the granules to be developed as viable progenies for release into the host system.
Fulltext In vitro culture of Toxoplasma gondii

Suresh K, Mak JW, Yong HS

Southeast Asian J. Trop. Med. Public Health, 1991 Sep;22(3):449-51.
PMID: 1818400
In vivo encystation of Blastocystis hominis

Suresh K, Venilla GD, Tan TC, Rohela M

Parasitol Res, 2009 Jun;104(6):1373-80.
PMID: 19238443 DOI: 10.1007/s00436-009-1340-1

Blastocystis from infected stools of a person who showed chronic symptoms of abdominal discomfort and diarrhea were examined over a 6-month period, using transmission electron microscopy, for the ultrastructural changes from vacuolar to cystic stage. The study confirms the irregular shedding phenomenon of the organism previously reported, and for the first time, records sequential changes in encystation in stools collected over a time period. The study also confirms the existence of a precystic stage which has an immature cell wall consisting of a layer of a homogenous electron-dense mass surrounding the cell which acts as a intermediatory stage between the vacuolar and cystic stage.
Infections of Blastocystis hominis and microsporidia in cancer patients: are they opportunistic?

Chandramathi S, Suresh K, Anita ZB, Kuppusamy UR

Trans R Soc Trop Med Hyg, 2012 Apr;106(4):267-9.
PMID: 22340948 DOI: 10.1016/j.trstmh.2011.12.008

Chemotherapy can cause immunosuppression, which may trigger latent intestinal parasitic infections in stools to emerge. This study investigated whether intestinal parasites can emerge as opportunistic infections in breast and colorectal cancer patients (n=46 and n=15, respectively) undergoing chemotherapy treatment. Breast cancer patients were receiving a 5-fluorouracil/epirubicin/cyclophosphamide (FEC) regimen (6 chemotherapy cycles), and colorectal cancer patients were receiving either an oxaliplatin/5-fluorouracil/folinic acid (FOLFOX) regimen (12 cycles) or a 5-fluorouracil/folinic acid (Mayo) regimen (6 cycles). Patients had Blastocystis hominis and microsporidia infections that were only present during the intermediate chemotherapy cycles. Thus, cancer patients undergoing chemotherapy should be screened repeatedly for intestinal parasites, namely B. hominis and microsporidia, as they may reduce the efficacy of chemotherapy treatments.
Isolate resistance of Blastocystis hominis to metronidazole

Haresh K, Suresh K, Khairul Anus A, Saminathan S

Trop Med Int Health, 1999 Apr;4(4):274-7.
PMID: 10357863

Isolates of Blastocystis hominis from infected immigrant workers from Indonesia, Bangladesh and infected individuals from Singapore and Malaysia were assessed for growth pattern and degree of resistance to different concentrations of metronidazole. Viability of the cells was assessed using eosin-brillian cresyl blue which stained viable cells green and nonviable cells red. The Bangladeshi and Singaporean isolates were nonviable even at the lowest concentration of 0.01 mg/ml, whereas 40% of the initial inoculum of parasites from the Indonesian isolate at day one were still viable in cultures with 1.0 mg/ml metronidazole. The study shows that isolates of B. hominis of different geographical origin have different levels of resistance to metronidazole. The search for more effective drugs to eliminate th parasite appears inevitable, especially since surviving parasites from metronidazole cultures show greater ability to multiply in subcultures than controls.
Long term maintenance of Toxoplasma gondii (Rh strain) in Vero cell line and use of harvested antigens for immunodiagnosis

Suresh K, Mak JW, Yong HS

Southeast Asian J. Trop. Med. Public Health, 1991 Dec;22 Suppl:124-8.
PMID: 1822869

Thirty in vitro serial passages of Toxoplasman gondii cultures in Vero cell line performed once in every five days had a mean increase in parasite count of 74.4 +/- 14.8 times from that of initial counts. Long term cultures in Vero cell line did not alter the virulence of the parasite. The good correlation (r = 0.99) between the IFA titer and ELISA OD values using the parasite antigens from in vitro sources indicates that long term maintenance of T. gondii in culture does not affect significantly the ability to recognize antibodies to surface and soluble antigens. The results also show that soluble antigens containing host cells can be directly used for immunodiagnostic purposes without purification. The in vitro maintenance of T. gondii is safer and cheaper when compared to the in vivo method.
Fulltext Modified Field stain - rapid viability test for Trichomonas vaginalis

Afzan MY, Sivanandam S, Suresh K

J Appl Microbiol, 2012 Jan;112(1):132-7.
PMID: 22040369 DOI: 10.1111/j.1365-2672.2011.05185.x

We previously reported that Modified Field Stain (MF) can be used as a rapid stain for diagnosis. In the present study we extend the observation to include the stain as an alternative method to assess viability of the cells.
Fulltext Optic disc swelling in a patient with tuberculous meningitis: a diagnostic challenge

Zuhaimy H, Leow SN, Vasudevan SK

BMJ Case Rep, 2017 Aug 09;2017.
PMID: 28794092 DOI: 10.1136/bcr-2017-221170

We discuss the diagnostic challenge in an adult patient presented with purely ocular symptoms diagnosed with tuberculous meningitis (TBM). A 38-year-old woman presented with bilateral painless blurring of vision. There were bilateral sixth cranial nerve palsy and bilateral optic disc swelling. Optic nerve function tests were normal. Patient was lucid with no signs of meningism. Brain imaging were normal. She had a positive Mantoux test, high erythrocyte sedimentation rate but no clinical evidence of active pulmonary tuberculosis infection. Her Quantiferon-TB Gold in-tube test was negative. Cerebrospinal fluid analysis revealed a high opening pressure but no biochemical parameters to suggest TBM, hence she was treated as idiopathic intracranial hypertension. A diagnosis of TBM was finally made following a positive PCR for Mycobacterium tuberculosis Her vision improved with reduction in optic disc swelling following antituberculous treatment.

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