Joon Wah MAK - Academia.edu (original) (raw)

Papers by Joon Wah MAK

Southeast Asian Journal of Tropical Medicine and Public Health, Jun 1, 1996

In vitro sensitivity of Acanthamoeba castellani was tested to three drugs: Chloroquine, ivermecti... more In vitro sensitivity of Acanthamoeba castellani was tested to three drugs: Chloroquine, ivermectin and fungizone (amphotericin B). Sensitivity was demonstrated to the latter two compounds but not to chloroquine. Thus ivermectin and amphotericin B show promise as therapeutic agents against this parasite.

The American Journal of Tropical Medicine and Hygiene, 1983

Adherence assays were used to demonstrate the in vitro effect of serum-dependent cellular adheren... more Adherence assays were used to demonstrate the in vitro effect of serum-dependent cellular adherence of human buffy coat cells to infective larvae of Brugia malayi in filariasis patients treated with antifilarial drugs. In this study, microfilaraemic patients were treated with either diethylcarbamazine citrate (DEC), mebendazole or levamisole hydrochloride. It was found that DEC and mebendazole decreased the motility of infective larvae due to a direct action of the drugs. Sera of levamisole-treated patients caused increased adherence of human buffy coat cells to infective larvae, leading to a decrease in motility and cuticular damage as confirmed by scanning electron microscopic studies. However, serum of levamisole-treated patients alone could cause a similar lethal effect on infective larvae. Studies with the indirect fluorescent antibody test suggested that IgM was involved in this phenomenon. Complement did not appear to be important.

The Southeast Asian journal of tropical medicine and public health, 1996

Transactions of the Royal Society of Tropical Medicine and Hygiene, 1982

References Amin, M. A. & Fenwick, A. (1977). The development of an annual regimen for blanket sna... more References Amin, M. A. & Fenwick, A. (1977). The development of an annual regimen for blanket snail control on the Gezira Irrigated Area of the Sudan. Annals of Tropical Medicine and Parasitology, 71, 205212. Greany, W. H. (1952). Schistosomiasis in the Gezira Irrigated Area of the Anglo-Egyptian Sudan. Annals of Tropical Medicine and Parasitology, 46, 250-267. Kardaman. M. H. (1979). A studv on the mevalence and clinical *manifestations of Schistokntiasis &tong differen?

Drug, Healthcare and Patient Safety, 2012

Background: For all medications, there is a trade-off between benefits and potential for harm. It... more Background: For all medications, there is a trade-off between benefits and potential for harm. It is important for patient safety to detect drug-event combinations and analyze by appropriate statistical methods. Mefloquine is used as chemoprophylaxis for travelers going to regions with known chloroquine-resistant Plasmodium falciparum malaria. As such, there is a concern about serious adverse events associated with mefloquine chemoprophylaxis. The objective of the present study was to assess whether any signal would be detected for the serious adverse events of mefloquine, based on data in clinicoepidemiological studies. Materials and methods: We extracted data on adverse events related to mefloquine chemoprophylaxis from the two published datasets. Disproportionality reporting of adverse events such as neuropsychiatric events and other adverse events was presented in the 2 × 2 contingency table. Reporting odds ratio and corresponding 95% confidence interval [CI] data-mining algorithm was applied for the signal detection. The safety signals are considered significant when the ROR estimates and the lower limits of the corresponding 95% CI are $2. Results: Two datasets addressing adverse events of mefloquine chemoprophylaxis (one from a published article and one from a Cochrane systematic review) were included for analyses. Reporting odds ratio 1.58, 95% CI: 1.49-1.68 based on published data in the selected article, and 1.195, 95% CI: 0.94-1.44 based on data in the selected Cochrane review. Overall, in both datasets, the reporting odds ratio values of lower 95% CI were less than 2. Conclusion: Based on available data, findings suggested that signals for serious adverse events pertinent to neuropsychiatric event were not detected for mefloquine. Further studies are needed to substantiate this.

Tropical biomedicine, 2019

Glycycometus malaysiensis is an allergenic domestic mite found in houses. G. malaysiensis is know... more Glycycometus malaysiensis is an allergenic domestic mite found in houses. G. malaysiensis is known to be highly similar to and is often mistaken as Blomia tropicalis, one of the major house dust mite species that causes asthma and allergic diseases in many tropical and subtropical regions. It was also suggested that these mites cross-react with each other and that the prevalence of G. malaysiensis might be higher than previous reports. A review on the taxonomic keys as well as light and scanning electron micrographs of G. malaysiensis are presented to appreciate the fine morphological structures of G. malaysiensis. The mouth, setae, legs (trochanter, femur, genu, tibia and tarsus) and the sexual organs (genital openings, genital setae and genital suckers) of G. malaysiensis are outlined. The morphology of G. malaysiensis is also compared with that of B. tropicalis to delineate the key features for the differentiation between these two mite species.

The American Journal of Tropical Medicine and Hygiene, 1980

The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samp... more The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samples obtained from patients and persons exposed to Wuchereria bancrofti and Brugia malayi in endemic areas of Peninsular Malaysia. A crude extract of adult worms of the rat filaria, Breinlia booliati, was used as the antigen. When a titer of 1:16 was taken as negative, positive IHA test rates in sera from microfilaria-negative persons in endemic areas, microfilaremic cases, and patients with clinical filariasis were 13%, 75%, and 80%, respectively. Results of the IHA test correlated well with results obtained with the indirect fluorescent technique.

The Southeast Asian journal of tropical medicine and public health, 1997

A dot-blot ELISA was compared with a previously performed sandwich ELISA for the detection of Par... more A dot-blot ELISA was compared with a previously performed sandwich ELISA for the detection of Parastrongylus cantonensis antigens in sera from patients. Using the same monoclonal antibody and the same sera, 6 of 10 sera (60%) from parastronglyiasis patients were positive in dot-blot ELISA, whereas with sandwich ELISA, 5 of the same patient sera (50%) were positive. The specificity in both assays was 100% using 50 sera from patients with other parasitic diseases; of these, 10 each were from patients with cysticercosis, filariasis, gnathostomiasis, malaria and toxocariasis. The control group consisted of 53 sera from normal health Thais and Malaysians. The sensitivity of the assays was, however, slightly better with dot-blot ELISA and because it is simple, quick and cost-effective, it may be a test of choice for specific diagnosis of human parastrongyliasis.

International e-Journal of Science, Medicine & Education

There is no substantial difference in conducting research that is both ethical and responsive to ... more There is no substantial difference in conducting research that is both ethical and responsive to the health needs in developing and developed nations. Differences are in financial constraints, technological expertise in identification and addressing needs, and in the perception of equal partnership of all stakeholders. There will be differences in emphasis of research but this is slowly blurred due to globalisation. Public health emergencies in developing countries need timely and effective global collaborative research to implement control strategies. Research needs should be based on predictive models with learning from past emergencies, technological advances, strategic critical appraisal of local and global health information, and dialogue with all stakeholders. Adequate funding will be challenging and resources from national, international and aid foundations will be needed. Issues associated with such funding include deployment of international rapid response teams, collaborating researchers, transfer of technology, and intellectual property ownership. While all types of research ranging from basic, applied, clinical studies, meta-analysis, and translational research are relevant, the relative importance and specific allocation of resources to these may differ. Is the choice related to responsiveness or based on researchers' perception of their contributions to evidence-based practice and research? Ethical issues relating to vulnerable groups, risk distribution, quality issues, research integrity and oversight are just as important. Internationally funded research including clinical trials must be sensitive to such issues to avoid allegations of exploitation. Thus the potential of utilisation and buy-in of research findings and recommendations must be considered.

Current Pharmaceutical Analysis, Jul 1, 2012

Effective, selective, precise and accurate liquid chromatographic analytical methods for the anal... more Effective, selective, precise and accurate liquid chromatographic analytical methods for the analysis of a novel chlorantraniliprole insecticide in technical and formulation (coragen, 20% SC) have been optimized and validated. Eight methods were designed based on different mobile phases, temperature and two HPLC columns. The mobile phase consists of two mixtures (acetonitrile:water, 70:30 and methanol:water, 70:30) with 25 or 40 C. HPLC analysis of chlorantraniliprole was carried out at a wavelength of 260 nm, with a flow rate of 0.8 mL/min. The calibration curves showed a good linear relationship (R 2 ˃ 0.99) in the injected quantities ranged from 0.0125 to 1.00 mg. Limit of detection (LOD) was found to be 3.94 to 14.56 ng and from 5.95 to 12.93 ng using the analytical methods I to IV by MicroPack CN-10 and V-VIII by ZORBAX Eclips Plus C18 columns, respectively, based on SDslope values. ZORBAX Eclips Plus C18 column with method VI was the best one (R 2 D 1.00 and RSD D 0.30), short retention time (4.936 min), high theoretical plates per column (65457.15) compared to others and LOD D 6.49 ng. The accuracy of the best method was demonstrated by recovery rates of 83.04% to 98.50% for grape samples supplemented with 5, 10 and 50 mg chlorantraniliprole/kg.

Expert Review of Clinical Immunology, 2006

Iron is an important trace element in the human body. The absorption of iron is strictly controll... more Iron is an important trace element in the human body. The absorption of iron is strictly controlled through hepcidin, while there are no efficient physiologic mechanisms to excrete iron from the body. Under conditions where iron metabolism is disturbed, such as in transfusion-dependent patients with thalassemia major, myelodysplastic syndromes, aplastic anemia, or sickle cell disease, excessive iron deposition occurs in the liver, heart, and endocrine organs, resulting in reactive oxygen species (ROS) through the Fenton and Haber-Weiss reaction. [1] ROS can attack components of cells [2,3] and further induce organ dysfunction, such as liver fibrosis, cirrhosis, hepatic carcinoma, [2] myocarditis, pericarditis, [4] and other diseases. [4-8] In the liver of chronic hepatitis C (CHC) patients, iron deposition has been found in both hepatocytes and reticuloendothelial cells [9-13] although the mechanism is not fully clarified. Like other viruses, hepatitis C virus (HCV) needs constituents of host cells to proliferate, and iron is one of the most important constituents. Many studies have explored the connection between iron overload and HCV life cycle with differing results. Some studies have found that iron promotes HCV replication, [14,15] while others have shown that iron suppresses HCV replication. [16-19] Most of the studies suggest the positive role of iron on HCV translation. [20-23] To summarize the interactions between HCV and iron, and understand the mechanisms of iron overload in CHC, we searched articles published in the PubMed databases up to January 28, 2017, to gain an in-depth understanding and knowledge of relevant areas.

Journal of Helminthology, 1987

ABSTRACTFour Presbytis cristata were treated with oral ivermectin at the same time as the subcuta... more ABSTRACTFour Presbytis cristata were treated with oral ivermectin at the same time as the subcutaneous inoculation of 100 infective larvae monthly for three months. Two animals given 0·2 mg/kg monthly and two others given 0·3 mg/kg monthly as well as three control animals became patent for microfilaraemia. However, only 1% of the infective dose was recovered as adult worms from animals in the higher drug dosage group compared to 8·2% and 6·2% in the lower dosage and control groups respectively.

Additional file 7. SROC plot of studies that used Pf LAMP.

Additional file 3. Characteristics of included studies.

Additional file 4. Summary of the methodological quality assessment across all studies.

Background: Numerous studies have reported that polymorphisms in the tumour necrosis factor-alpha... more Background: Numerous studies have reported that polymorphisms in the tumour necrosis factor-alpha (TNF-a-308) gene are implicated in susceptibility to gastric cancer. However, individual genetic association studies that assessed the relationship between TNF-a- 308 and the risk of gastric cancer showed inconclusive results. The objective of this study was to synthesis evidence on the association between polymorphisms in the TNF-a-308 and gastric cancer risk. Methods: This is a meta-analysis of genetic association studies. We searched relevant case-control studies, assessing TNF- 308 polymorphisms and gastric cancer in health-related electronic databases. The methodological quality of included studies was assessed by the Newcastle-Ottawa quality assessment scale. The strength of association was calculated as odds ratios (ORs) with its 95% confidence intervals (CIs). Pooled ORs and 95 % CIs were estimated using random-effect model or fixed effect model, based on between-study heterogen...

Parasitology Open, 2016

SUMMARYToxoplasmosis affects a third of the global population and is of particular concern for im... more SUMMARYToxoplasmosis affects a third of the global population and is of particular concern for immunologically compromised individuals. Toxoplasmosis induces host physiological events ranging from immunological to metabolic responses across multiple biological compartments. To understand the sequence of host responses during acute and chronicToxoplasma gondiiinfection, eight male BALB/c mice were infected with 2000T. gondiiME49 tachyzoites with a further eight uninfected mice used as controls. Plasma cytokines status, urinary metabolic profiling and fecal microbial profiles were characterized to monitor temporal variation related toT. gondiiinfection. The results showed elevated serum interferon-γ(IFN-γ), interleukin-12p40 and necrosis factor-αduring acute phase of infection with concomitant perturbation in host energy metabolism and host-gut microbiome co-metabolism of phenolics and a shift in microbial composition. However, the differences were less pronounced during the putative...

Tropical biomedicine, 2004

Intestinal protozoa are increasingly being studied because of their association with acute and ch... more Intestinal protozoa are increasingly being studied because of their association with acute and chronic diarrhoea in immunocompromised as well as immunocompetent patients. Various community outbreaks due to contamination of water or food with these protozoa have further highlighted their importance in public health. Among these important pathogens are Giardia duodenalis, Entamoeba histolytica, Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli, and microsporidia. Except for the cyst-forming G. duodenalis and E. histolytica, the others are intracellular and form spores which are passed out with the faeces. These organisms are also found in various animals and birds and zoonotic transmission is thought to occur. These infections are distributed worldwide, with a higher prevalence in developing compared to developed countries. However, the relative importance of zoonotic infections especially in developing countries has not been studied in detail. The prevalence rates are g...

The Southeast Asian journal of tropical medicine and public health, 1988

Biotechnological tools are being used in malaria, filariasis and dengue research. The main emphas... more Biotechnological tools are being used in malaria, filariasis and dengue research. The main emphasis has been on the production of reagents for immunodiagnosis and research. In this respect monoclonal antibodies (McAbs) against various species and stages of the above pathogens have been produced. It is hoped that these McAbs will be useful not only in immunodiagnosis but also for seroepidemiological applications. A DNA probe against Brugia malayi has been tested in Malaysia and was found to be sensitive and specific.