MyMedR

Fulltext Optimization for extraction on total phenolic content and radical scavenging capacity of Henna (Lawsonia inermis) stems using response surface methodology

Tan, M. C., Tan, C. P., Khoo, H. E., Ho, C. W.

International Food Research Journal, 2014;21(2):789-794.

MyJurnal

This study aimed to optimise potential extraction conditions using response surface methodology (RSM) for yielding maximum levels of total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging capacity of henna (Lawsonia inermis) stems. The ranges for selected independent variables, namely acetone concentration (20−90%, v/v), extraction time (10−90 min), and extraction temperature (25−45°C) were identified by screening tests. Optimum conditions obtained for extraction of TPC were 47.0% acetone, extraction time of 47.6 min and extraction temperature of 37.3oC. The result also showed that 75.8% acetone, extraction time of 26.2 min and extraction temperature of 41oC yielded the highest DPPH• scavenging capacity. The optimized extraction conditions have resulted in TPC and DPPH• scavenging capacity of 5232.4 mg GAE/100 g DW and 6085.7 mg TE/100 g DW, respectively which similar to the predicted values. Therefore, RSM has successfully optimized the extraction conditions for TPC and radical scavenging capacity of henna stems.

Fulltext A study of newly diagnosed epilepsy in Malaysia

Manonmani V, Tan CT

Singapore Med J, 1999 Jan;40(1):32-5.

PMID: 10361483

To determine the characteristics of newly diagnosed epilepsy in the multiracial population of Malaysia.

Fulltext Malaysian children with: "benign epilepsy of childhood with centrotemporal spikes"

Manonmani V, Tan CT

Singapore Med J, 1994 Jun;35(3):247-9.

PMID: 7997896

Benign epilepsy of childhood with centrotemporal spikes (BECT) was studied in Malaysian children, and was observed in Chinese, Malay and Indian children in the ratio 10:6:5. There were 12 boys and 9 girls. Fit frequency varied from almost daily to a single fit. The age of onset ranged from 2-13 years and BECT was not noted in any child over 13 years old. There was a strong circadian rhythm and fits occurred mainly in sleep. Generalised seizures were more common than partial seizures. During the 3-year study from April 1989 to April 1992, 21 children with BECT were identified from the EEG records done at the University Hospital and it was found that this genetic epilepsy which is autosomal dominant with age dependent penetrance occurs in approximately 4.8% of our epileptic children. In addition there were 3 children in whom petit mal co-existed with a BECT EEG trait.

Fulltext Juvenile myoclonic epilepsy--a report of 11 patients at the University Hospital, Kuala Lumpur

Manonmani V, Tan CT

Singapore Med J, 1993 Oct;34(5):378-80.

PMID: 8153678

This is a report on 11 cases of Juvenile Myoclonic Epilepsy (JME) from the University Hospital, Kuala Lumpur, all of whom were diagnosed in the last one and a half years. This genetic syndrome is seen in all the three main racial groups: Chinese, Malays and Indians. It accounts for 2% of the epilepsy patients seen at the neurology clinic. Lack of awareness is the main hindrance to diagnosis.
Study site: Neurology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia

Fulltext Evoked response study among Malaysian multiple sclerosis patients

Tan CT, Leong S

Singapore Med J, 1992 Dec;33(6):575-80.

PMID: 1488664

A study of visual evoked potential (VEP), brainstem evoked potential (BAEP) and median nerve somatosensory evoked potential (SSEP) in 26 Malaysian patients with clinically definite Multiple Sclerosis (MS). This study showed an overall high rate of abnormality, with 85% of patients for VEP, 31% for BAEP and 65% for median nerve SSEP. The rate of abnormality was particularly high for patients who were symptomatic, reaching 100% of patients for VEP, 50% of patients in BAEP, 83% of nerves for median nerve SSEP. The rate of abnormality among those who were asymptomatic was lower, varying from 32% of eyes in VEP, 27% of patients in BAEP and 31% of nerves in median nerve SSEP. Three out of 10 patients with optic spinal form of MS have abnormal BAEP. These show the usefulness of the evoked potential studies in confirming the clinical lesions as well as demonstrating subclinical involvement. The rate of abnormal evoked responses for the asymptomatic patients in this study is generally lower than that published elsewhere.

Clinical and pathological manifestations of human henipavirus infection

Wong KT, Tan CT

Curr. Top. Microbiol. Immunol., 2012;359:95-104.

PMID: 22427144 DOI: 10.1007/82_2012_205

The clinicopathological features of human Nipah virus and Hendra virus infections appear to be similar. The clinical manifestations may be mild, but if severe, includes acute encephalitic and pulmonary syndromes with a high mortality. The pathological features in human acute henipavirus infections comprise vasculopathy (vasculitis, endothelial multinucleated syncytia, thrombosis), microinfarcts and parenchymal cell infection in the central nervous system, lung, kidney and other major organs. Viral inclusions, antigens, nucleocapsids and RNA are readily demonstrated in blood vessel wall and numerous types of parenchymal cells. Relapsing henipavirus encephalitis is a rare complication reported in less than 10% of survivors of the acute infection and appears to be distinct from the acute encephalitic syndrome. Pathological evidence suggests viral recrudescence confined to the central nervous system as the cause.

Fulltext Acute renal failure and posterior reversible encephalopathy syndrome following multiple wasp stings: a case report

Loh HH, Tan CHH

Med J Malaysia, 2012 Feb;67(1):133-5.

PMID: 22582570 MyJurnal

Wasp stings can present in various ways, ranging from mild self-limiting illness to severe multi organ failure with a potentially fatal outcome. We report a case of multiple wasp stings leading to acute renal failure needing prolonged dialysis support and posterior reversible encephalopathy syndrome.

Fulltext A review of multiple sclerosis with Asian perspective

Chong HT, Tan CT

Med J Malaysia, 2008 Dec;63(5):356-61.

PMID: 19803290 MyJurnal

Multiple sclerosis, although a rare disease in Asia, often presents significant diagnostic challenges to clinicians. There has been rapid advancement in the understanding of the underlying genetic influence, pathophysiology, investigation and treatment recently. This paper reviewed the latest development of various aspects of the disease and examined the differences between the manifestations of Asian and Western patients. The implications of these differences to investigation and treatment were also touched upon.

Fulltext The current practice of sedation and analgesia in intensive care units in Malaysian public hospitals

Ahmad N, Tan CC, Balan S

Med J Malaysia, 2007 Jun;62(2):122-6.

PMID: 18705443 MyJurnal

We sought to review the current practice of sedation and analgesia in intensive care units (ICUs) in Malaysian public hospitals. A questionnaire survey was designed and sent by mail to 40 public hospitals with ICU facility in Malaysia. The anaesthesiologists in charge of ICU were asked to complete the questionnaire. Thirty seven questionnaires were returned (92.5% response rate). Only 35% respondents routinely assess the degree of sedation. The Ramsay scale was used prevalently. A written protocol for sedation was available in only 14 centers (38%). Although 36 centers (95%) routinely adjust the degree of sedation according to patient's clinical progress, only 10 centers (14%) interrupt sedation on a daily basis. Most respondents agreed that the selection of agents for sedation depends on familiarity (97%), pharmacology (97%), the expected duration for sedation (92%), patient's clinical diagnosis (89%) and cost (73%). Midazolam (89%) and morphine (86%) were the most commonly used agents for sedation and analgesia, respectively. Only 14% respondents still frequently use neuromuscular blocking agents, mostly in head injury patients. Our survey showed similarity in the choice of sedative and analgesic agents in ICUs in Malaysian public hospitals comparable to international practice. Nevertheless, the standard of practice could still be improved by implementing the practice of sedation score assessment and daily interruption of sedative infusion as well as having a written protocol for sedation and analgesia.

High-titred neutralizing antibodies to human enterovirus 71 preferentially bind to the N-terminal portion of the capsid protein VP1

Tan CS, Cardosa MJ

Arch Virol, 2007;152(6):1069-73.

PMID: 17318736

Human enterovirus 71 has emerged as an important pathogen of children in the Asia Pacific region, and it may be important to consider the development of a vaccine against this virus. Human cord serum was used as a source of neutralizing antibodies to determine whether the N- or C-terminal half of the VP1 capsid protein was more likely to harbour neutralizing determinants. Cord sera from 205 individuals were tested for neutralizing antibodies against human enterovirus 71 in an indirect ELISA against recombinant VP1 antigen as well as the N- and C-terminal portions of VP1 antigen. High-titred human neutralizing antibodies were significantly more reactive with the N-terminal half of VP1 than weak or negative sera. The N-terminal half of human enterovirus 71 is likely to have important neutralizing antibody determinants and should be investigated further in vaccine development efforts.

Nipah encephalitis outbreak in Malaysia

Tan CT, Wong KT

Ann Acad Med Singap, 2003 Jan;32(1):112-7.

PMID: 12625108

INTRODUCTION: Between September 1998 and June 1999, there was a severe outbreak of viral encephalitis among the pig farm workers in Malaysia.

METHODS: This is a review of the published literature related to the outbreak with the focus on human diseases.

RESULTS: The encephalitis was caused by a newly discovered paramyxovirus related to Hendra virus, later named Nipah virus. There were 265 patients with acute encephalitis. The disease is thought to spread from pig to man through close contact. The risk of human-to-human spread is thought to below. The disease affected mainly adult Chinese males, half of whom had affected family members. The disease presented mainly as acute encephalitis with a short incubation period of less than two weeks, with the main symptoms of fever, headache, and giddiness followed by coma. Distinctive clinical signs include segmental myoclonus, areflexia and hypotonia, hypertension, and tachycardia. Initial cerebrospinal fluid was abnormal in 75% of patients. Serology was helpful in confirming the diagnosis. Magnetic resonance imaging showed distinctive changes of multiple, discrete, and small high signal lesions, best seen with fluid-attenuated inversion recovery (FLAIR) sequences. Mortality was high at 40% and death was probably due to severe brainstem involvement. The main necropsy finding in acute encephalitis was that of disseminated microinfarction associated with vasculitis and direct neuronal involvement. Ribavirin was able to reduce the mortality by 36%. Relapse encephalitis was seen in 7.5% of those who recovered from acute encephalitis, and late-onset encephalitis in 3.4% of those with initial non-encephalitic or asymptomatic diseases. The mean interval between initial illness and the onset of the complication was 8.4 months. The relapse and late-onset encephalitis which manifested as focal encephalitis arose from recurrent infection.

CONCLUSION: Nipah virus, a recently discovered paramyxovirus, causes a unique encephalitis with high mortality as well as relapse and late-onset encephalitis. The infection is mainly spread from pigs to man.

Plasmapheresis in the University of Malaya Medical Centre, Malaysia

Chong HT, Tan CT

Ther Apher, 2001 Apr;5(2):147-9.

PMID: 11354300

Over the past 3 decades, plasmapheresis has been used more extensively for a variety of neurological and hematological disorders. We undertook a retrospective review to ascertain its safety, efficacy, and factor(s) that predispose to poor outcome. We reviewed 117 plasma exchanges in 24 patients with a mean age of 43 +/- 15 years; half were male. A total of 79% of the patients had neurological diseases, and the most common were chronic inflammatory demyelinating polyneuropathy, Guillain-Barré syndrome, and myasthenic crisis. Plasmapheresis was effective in 79% of the patients, especially for neurological indications. Complications occurred in 23% of the exchanges affecting 58% of the patients. Most complications were mild; sepsis was the most common (9.4% of exchanges), especially catheter related sepsis (6%), rash (4.3%), and hypotension (4.3%). Only 2 (8%) patients had severe complications that required mechanical ventilation. There were 5 mortalities (21%), 3 due to sepsis and 2 due to myocardial ischemia and arrhythmia, none of which occurred within 48 h of the last exchange. Patients with poor renal function had higher mortality. Overall, our figures agree with those from other institutions and indicate that plasma exchange is an effective and safe procedure, especially for a variety of neuroimmunological conditions.

Fulltext Neurosyphilis--a clinical survey

Loh TG, Tan CT

Med J Malaysia, 1980 Dec;35(2):112-6.

PMID: 7266402

A report of 25 cases of neurosyphilis seen in University Hospital, Kuala Lumpur since 1970. Classical form of the disease still constitute the majority of the patients with often long delay before diagnosis.

Fulltext Myasthenia gravis--a clinical survey in Malaysia

Tan CT, Loh TG

Med J Malaysia, 1980 Dec;35(2):144-9.

PMID: 7266408

A retrospective study of 62 cases of myasthenia gravis in Malaysia is reviewed. It shows an apparent prevalence among the ethnic Chinese compared with the Malay and Indian. The incidence of male and female and their average age of onset are similar. Unlike the western figure, among those with age of onset less than 20 years. both sexes are equally affected. The symptomatology, morbidity and mortality and incidence of thymoma are the same as those
reported elsewhere.

A comparative study of cobra (Naja) venom enzymes

Tan NH, Tan CS

Comp. Biochem. Physiol., B, 1988;90(4):745-50.

PMID: 2854766

1. The L-amino acid oxidase, hyaluronidase, alkaline phosphomonoesterase, protease, phosphodiesterase, acetylcholinesterase, phospholipase A and 5'-nucleotidase activities of 47 samples of venoms from all the six species of cobra (Naja), including five subspecies of Naja naja, were examined. 2. The results demonstrated interspecific differences in the venom contents of phospholipase A, acetylcholinesterase, hyaluronidase and phosphodiesterase. These differences in venom enzyme contents can be used for the differentiation of species of the genus Naja. 3. Thus, our results revealed a correlation between the enzyme composition of venom and the taxonomic status of the snake at the species level for the genus Naja.

Acidimetric assay for phospholipase A using egg yolk suspension as substrate

Tan NH, Tan CS

Anal Biochem, 1988 May 1;170(2):282-8.

PMID: 3394929

A convenient acidimetric assay for phospholipase A using egg yolk suspension as substrate has been developed. The substrate mixture consists of 1 part egg yolk, 1 part 8.1 mM sodium deoxycholate, and 1 part 18 mM calcium chloride. Phospholipase A activity is measured by following the initial rate of pH change, which is linear between pH 8.0 and 7.75 and is proportional to enzyme concentration over a wide range. The assay is highly reproducible, with a coefficient of variation of 3%, and as sensitive as most established assays for phospholipase A. The assay uses inexpensive and easily available substrate and is simple to perform. It is particularly useful for monitoring phospholipase A activity in chromatography fractions.

The enzymatic activities and lethal toxins of Trimeresurus wagleri (speckled pit viper) venom

Tan NH, Tan CS

Toxicon, 1989;27(3):349-57.

PMID: 2543103

Trimeresurus wagleri (speckled pit viper) venom exhibited the usual set of enzyme activities occurring in pit viper venoms but the content of alkaline phosphomonoesterase was unusually high, whereas the proportions of protease and arginine ester hydrolase were very low. The venom also exhibited weak thrombin-like activity but did not exhibit hemorrhagic or anticoagulant activity. Analysis of the Sephadex G-200 gel filtration fractions of the venom indicated that the lethal fraction was a low mol.wt protein, and that fractions exhibiting phosphodiesterase, phosphomonoesterase, arginine ester hydrolase, thrombin-like enzyme, L-amino acid oxidase and phospholipase A activities were not lethal. Two lethal toxins, designated as wagleri toxins 1 and 2, were isolated from the venom using Sephadex G-50 gel filtration chromatography followed by SP-Sephadex C-25 ion exchange chromatography. The mol.wts of the two toxins were 8900 by gel filtration. The LD50 (i.v.) values in mice for wagleri toxins 1 and 2 are 0.17 microgram/g and 0.19 microgram/g, respectively.

Partial purification of acetylcholinesterase from the venom of the shore pit viper (Trimeresurus purpureomaculatus)

Tan NH, Tan CS

Toxicon, 1988;26(5):505-8.

PMID: 3188057

Trimeresurus purpureomaculatus venom acetylcholinesterase has been partially purified by Sephadex G-200 gel filtration chromatography and DEAE Sephacel ion exchange chromatography. The enzyme has a mol. wt of 58,600. It was strongly inhibited by physostigmine salicylate and edrophonium chloride and exhibited substrate inhibition at high substrate concentration. The content of acetylcholinesterase in Trimeresurus purpureomaculatus venom was estimated to be much less than 0.3%.

Enzymatic activities of Malayan cobra (Naja naja sputatrix) venoms

Tan NH, Tan CS

Toxicon, 1987;25(11):1249-53.

PMID: 3433296

The enzymatic activities of four samples of Malayan cobra venom were investigated. There was significant variation in the contents of L-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase A, 5'-nucleotidase and hyaluronidase. The phosphodiesterase content was, however, constant. Storage of the lyophilized venom powder at 25 degrees C for 1 month did not affect the enzymatic activities. The venom enzymatic activities were generally also stable at 4 degrees C in 0.85% saline solution. After incubation at 37 degrees C for 39 days in 0.85% saline solution, the venom still retained considerable amounts of enzymatic activities. SP-Sephadex C-25 ion-exchange chromatography of the venom showed that the phospholipase A, L-amino acid oxidase, 5'-nucleotidase, phosphodiesterase and alkaline phosphomonoesterase exist in multiple forms.

Fractionation of Sumatran pit viper (Trimeresurus sumatranus sumatranus) venom by DEAE-Sephacel ion exchange chromatography and some biological properties of the fractions

Tan NH, Tan CS

Toxicon, 1989;27(6):697-702.

PMID: 2749766

Sumatran pit viper (Trimeresurus sumatranus sumatranus) venom was fractionated by DEAE-Sephacel ion exchange chromatography into seven fractions. Fractions 4, 5 and 6 were lethal to mice and exhibited strong hemorrhagic activity, as well as some enzymatic activities. Fraction 6 also exhibited potent anticoagulant and thrombin-like activities. Analysis of the biological and enzymatic properties of the three lethal fractions suggests that the major lethal component of fractions 4 and 5 may be the hemorrhagic principle, and that the lethality of fraction 6 may be due to the hemorrhagic principle and/or the anticoagulant principle.

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