1.Plant-Derived Antimalarial Agents: From Crude Extracts To Isolated Bioactive Compounds
Malaysian Journal of Medicine and Health Sciences 2011;7(2):87-98
Despite decades of intense research, malaria remains a deadly disease of the developing worlds. Drugresistance
to limited available antimalarials, in part, has contributed to the persistence of this infectious
disease. Likewise, the use of antimalarials such as artemisinin, though effective in global malaria control
programs, is hampered by high cost and limited supply. Therefore, identification of an antimalarial
drug that is easy to isolate and produce, inexpensive, and demonstrates little toxicity across a diverse
population represents the ideal agent needed for global malaria control programs and eradication of
this deadly disease. This review discusses several antimalarial compounds containing unique structural
composition that have been isolated and characterized from plant sources. These compounds have
exhibited promising antimalarial activities in vitro and in vivo. However, limitations such as toxicity,
low bioavailability and/or poor solubility have probably restricted the scope of use for several plant
products in humans. Nevertheless, plants provide novel leads, which can be developed into safe drugs
by synthetic strategies as exemplified by artemether and quinoline class of antimalarials. Therefore,
plant bioactive compounds described herein provide useful alternatives, which could be modulated
to obtain antimalarials active against not only drug-sensitive, but also drug-resistant and multi-drug
resistant strains of Plasmodium. In this direction, semi synthetic approaches to newer and modified
antimalarials have provided useful insights into their applicability in antimalarial drug discovery.
2.Toxoplasma gondii Recombinant Surface Antigen (SAG 1;P 30) and its Applications in Serodiagnosis and Vaccine Development for Toxop;asmosis
Malaysian Journal of Medicine and Health Sciences 2010;6(1):1-18
Toxoplasmosis, caused by an intracellular protozoan parasite, Toxoplasma gondii, is widespread throughout the world. The disease is of major medical and veterinary importance, being a cause of congenital disease and abortion in humans and in domestic animals. In addition, it has gained importance recently due to toxoplasma encephalitis in AIDS patients. T.gondii was discovered 100 years ago. Its identification was rapidly followed by the recognition that it was a human pathogen. During the past 100 years, the spectrum of disease caused by this ubiquitous pathogen has expanded to include both congenital and acute infections as well as the recognition of diseases caused by this pathogen in the immune-compromised host. Recent data on behavioural changes in animals due to chronic toxoplasmosis is leading to research on the effect of this pathogen on the behaviour of human. Experimental studies on T.gondii have resulted in it becoming a model organism for studies on host pathogens interactions. Integration of clinical and experimental data on T.gondii should continue to lead to important insight into improvements in diagnosis for clinical management and vaccine development for control of toxoplasmosis.
3.A Bionomic Study of Hymenopteran Parasitoids at the Taman Beringin Landfill in Kepong and a Poultry Farm in Sungai Pelek, Selangor, Malaysia
Baharudin Omar ; Raja M. Zuha Raja Kamal ; Daniel Goh Chuan Lee ; Wan Omar Abdullah ; John Jeffery
Malaysian Journal of Health Sciences 2008;6(2):15-21
A four-month cross-sectional study found five species of parasitoids parasitizing puparia of filth flies breeding at the Taman Beringin landfill in Kepong and a
poultry farm in Sungai Pelek, Sepang, Selangor. Effect of monthly rainfalls towards density of flies and percentage of parasitoids emerging from collected
puparia were also analyzed. Spalangia sp. was the most common, consisting of Spalangia endius Walker, S. cameroni Perkins and S. gemina Boucek. Other parasitoids collected were Pachycrepoideus vindemmiae Rondani and
Exoristobia phillipinensis Ashmead. The parasitized fly hosts were Musca domestica Linn. and Chrysomya megacephala Fabricius. S. endius was the most common parasitoid attacking M. domestica at both locations. M. domestica
was the most common fly found at the Sg. Pelek poultry farm whereas C. megacephala was the most numerous at the Taman Beringin landfill. During heavy rainfall month of November 2003, density of flies were high whereas the
emerging parasitoids were low at both landfill and poultry farm. The present study revealed the endemic presence of parasitoids especially S. endius in both poultry farm and garbage landfill and the potential of the parasitoid species in fly control in Malaysia.
4.In vitro Antiplasmodial Activity and Cytotoxicity of Ten Plants Used as Traditional Medicine in Malaysia
Wan Omar Abdullah ; Ngah Zasmy Unyah ; Rukman Awang Hamat ; Baharudin Omar ; Mohamed Kamel Abd Ghani ; Mohammad Rayani ; Gholam Reza HAtam
Malaysian Journal of Health Sciences 2011;9(2):5-8
Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on chloroquineresistant strain of Plasmodium falciparum (FCB strain), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human diploid embryonic lung cells. Most extracts of ten selected plants used in Malay traditional medicine in Malaysia had activity in vitro. This supports continued investigations of traditional medicine in the search for new antimalarial agent. The compounds responsible for the observed antiplasmodial effects are under investigation.
5.Descriptions of the Larval Instars of Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae), a Species of Forensic Importance in Malaysia
Raja M. Zuha Raja Kamal ; Mohamed Abdullah Marwi ; John Jeffery ; Ahmad Firdaus Mohd. Salleh ; Wan Omar Abdullah ; Baharuddin Omar
Malaysian Journal of Health Sciences 2008;6(2):35-41
The anatomical structures of the first, second and third instars of Chrysomya rufifacies (Macquart) were examined by light microscopy. Observations were
documented on the three main characteristics; the cephalopharyngeal skeleton, anterior spiracle and posterior spiracle. The first instar larva bore cornuae of
fairly pigmented delineation with slim hypostomal sclerite and distinct dental sclerite. First instar did not have obscured anterior spiracle but posterior
spiracles were obscured with thin lining of opened peritreme. Intersegmental spines were evident. The second instar larva displayed a prominent anterodorsal
process approaching closer to hypostomal sclerite while upper margin of the dorsal cornua was slightly pigmented. Each anterior spiracle consisted of
nine to ten papillae, arranged in a single row. Peritreme of the posterior spiracle thick, opening at the end of peritreme was not wide and confined to
two spiracular slits. The third instar larva showed a prominent arch of the ventral cornua with broad and bold appearance. It approached the dorsal
cornua and became narrow at the incision median. The anterior spiracle consisted of a single row of nine to ten papillae while intersegmental spine
could be identified with one to three dark pigmented tips. A dark pigmented and wide periterime was observed confining three short and thick spiracular
slits while button was poorly pigmented. The most distinctive feature of this second and third instar larva was the slender, thorn-like tubercle with numerous
spined tips on the middle line segment of the body. These findings provide identification features of C. rufifacies larvae instars.
7.Intestinal microsporidiosis: A new entity in Malaysia?
A.H. Rukman ; O. Malina ; M.I. Noorhayati * ; M. Marlyn ** ; A. Wan Omar ; A.M. Roslaini ; Z. Ngah ; M. Norhayati *
Malaysian Journal of Medicine and Health Sciences 2008;4(2):11-24
Intestinal microsporidia is an emerging human disease caused by microsporidia. A study was conducted to determine the prevalence of microsporidia in patients with gastro-intestinal symptoms and to examine the clinical manifestations associated with intestinal microsporidiosis. A descriptive cross-sectional study using a well-structured questionnaire; a review of medical records was also undertaken. Positive stool samples were defined as presence of one or more pinkish-violet ovoid structures with a belt-like stripe under high power field (100x) using modified gram-chromotrope stain (MGC). A total of 353 faecal specimens of patients was examined and 100 patients were found to have positive stool samples for microsporidia. The overall prevalence of microsporidia was 28.3%. Acute and chronic diarrhoea were seen in 49.0% and 36.0% patients, respectively. The commonest clinical presentations were diarrhoea (85.0%) with 83.0% of patients having loose or watery stools, vomiting (75.0%), foul-smelling stools (60.0%), nausea (59.0%) and cramping abdominal pain (39.0%). The least common symptoms were fever (15.0%), mucous in stool (5.0%) and blood in stool (4.0%). This study concludes that the prevalence of microsporidia is still high (28.3%) and the majority of patients (93.0%) are symptomatic; the most common gastro-intestinal symptom is diarrhoea with loose or watery stools. Hence, it is recommended that a stool screening for microsporidia be done in selected patients presented with gastrointestinal symptoms.
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8.The Impact of Preventive Fogging on Entomological Parameters in a University Campus in Malaysia
A Ruhil Amal ; O Malina ; AH Rukman ; U Ngah Zasmy ; A Wan Omar ; M Norhafizah
Malaysian Journal of Medicine and Health Sciences 2011;7(1):9-16
Introduction: Preventive fogging is defined as space spraying of insecticide against mosquitoes in
order to prevent outbreak of mosquito borne infection. Despite provision of various preventive and
control activities against dengue and chikungunya infection by Ministry of Health Guideline, the detail
on preventive fogging has not yet specified. However, this has been adopted by certain institutions as
part of the routine strategies against dengue outbreak. A study on preventive fogging was conducted
in one of the hostels in Universiti Putra Malaysia. The research was done for 16 weeks in which one
routine fogging activity was done at the mid period of study. The main objectives of this study were to
determine the effectiveness of preventive fogging activities against Aedes mosquitoes and to identify
the distribution and abundance of Aedes mosquitoes in the area. Method: The fogging activity was
carried out by the management staff as part of their preventive measures in the student hostels. Ovitrap
was used as an indicator to monitor the impact of fogging activity and its continuous surveillance was
monitored weekly. The ovitraps were placed indoors and outdoors. Species identification was carried
out in the laboratory. The SPSS program was used to analyse the statistical data on the effectiveness of
fogging activity. Larval count (indoors and outdoors) and ovitrap index (OI) readings were identified
as ovitrap surveillance data for statistical analysis. Results: The results showed that Aedes albopictus
was the only species of the genus Aedes found in this hostel. The area had been highly infested by Ae.
Albopictus as indicated by high Ovitrap Index ranging between 48.33% to 90.00%. The mean (SD) of
Ovitrap Index was reduced from 71.67% (12.73%) (before the preventive fogging), to 69.42% (14.40%)
(after the fogging). Overall reduction in mosquito and larval density was also observed between pre
and post fogging activity in this study. Conclusion: The implementation of preventive fogging has
favourably reduced the dengue vector population up to 5 weeks after the introduction of preventive
fogging. However, sole dependency on preventive fogging may lead to insecticide resistance. Revisiting
the policy on preventive fogging; and identifying it as an additional tool for preventing dengue infection
in higher learning institutions are recommended.
9.A recombinant 19 kDa Plasmodium berghei merozoite surface protein 1 formulated with alum induces protective immune response in mice.
A Wan Omar ; A M Roslaini ; Z U Ngah ; A A Azahari ; M Zahedi ; O Baharudin
Tropical biomedicine 2007;24(1):119-26
We investigated the immunogenicity of recombinant rMSP1 (rPbMSP1) that was generated from Plasmodium berghei. The rPbMSP1 formulated in alum was found to be immunogenic which induced high levels of specific anti-rPbMSP1 antibody. The IgG2a response predominated over IgG1 during the challenge infection in the vaccinated mice. Mice vaccinated with rPbMSP1 in alum mounted significant protective immunity against challenge infection (P < 0.01). On day 121 after the booster, three out of ten mice immunized with rPbMSP1 in PBS survived parasite infection (P < 0.05) and eight out of ten mice vaccinated with r MSP1 in alum did (P < 0.01). Hence, immunization with MSP1 in alum obviously has conferred protective effects, which prevented death from P. berghei lethal infection in mice (P < 0.01). These observations provide an excellent model for clinical assessment of this formulation in human subjects.
aluminum sulfate
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Laboratory mice
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upper case pea
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Infection as complication of medical care
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10.Butterflies (Lepidoptera: Nymphalidae) Associated with Pig Carrions in Malaysia
Heo Chong Chin ; Mohamad Abdullah Marwi ; John Jeffery ; Sofian-Azirun M ; Chen Chee Dhang ; Wan Omar Abdullah ; Ismarulyusda Ishak ; Baharudin Omar
Malaysian Journal of Health Sciences 2010;8(1):1-4
An entomological study was conducted in Tanjung Sepat, Selangor, Malaysia in May until September 2007 revealing
five species of butterflies (all from family Nymphalidae) were attracted to pig carcasses placed in an oil palm plantation. Euploea mulciber (Cramer 1777), Hypolimnas bolina (Linnaeus 1758), Elymnias hypermnestra (Linnaeus 1763), Mycalesis mineus (Linnaeus 1758) and Ypthima baldus (Fabricius 1775) came to the carcasses at different stages of decomposition. From this study, we know that nymphalid butterflies are attracted to carcasses but their roles are most probably unimportant in post-mortem estimation.