Biomedical subjects

Yaowalark Sukthana

Publications and source records attributed to Yaowalark Sukthana.

11 recordsLinked to original sources

PubMed2006

Toxoplasmosis: beyond animals to humans.

The parasitic zoonosis toxoplasmosis, which was poorly understood before the advent of the HIV epidemic, has become a major clinical problem worldwide. Humans acquire toxoplasmosis from cats, from consuming raw or undercooked meat and from vertical transmission to the foetus through the placenta during pregnancy. Studies of the unique environmental factors in various communities indicate the important roles that eating habits and culture have on the transmission of this infection. The socioepidemiological aspects of toxoplasmosis are thought to be important contributing factors for the spread of this disease. Preventative measures should consider the cultures and beliefs of people in various communities more than solving poverty and giving orthodox health education.

Animals↗

PubMed2005

An exotic sinusitis.

We report a case of sinusitis caused by mixed free-living amoebae, Acanthamoeba and Naegleria, in an immunocompetent host; this has not been documented before. Free-living amoebae should be considered in the differential diagnosis of pathogens that cause sinusitis with or without central nervous system involvement, especially when bacteria or fungi are not found by smear, biopsy or culture.

Acanthamoeba↗

PubMed2005

Sensitivity and specificity of polymerase chain reaction for the detection of Toxoplasma gondii DNA added to laboratory samples.

We studied the sensitivity and specificity of PCR to detect T. gondii DNA by aliquoting various concentration of tachyzoites into laboratory specimens from 60 positive and 10 negative buffy-coat samples. We were able to detect the specific gene from purified DNA samples containing as few as 0.25 parasites per 100,000 human leukocytes. These results had an impressive initial 100% specificity but later it decreased because of false-negative data.

Animals↗

PubMed2005

Free-living ameba contamination in natural hot springs in Thailand.

Thermo tolerant free-living ameba, Naegleria spp and Acanthamoeba spp contamination in natural hot springs in Thailand were carried out from 13 provinces. The temperature of hot springs water varied from 28 degrees-65 degrees C and pH from 6-8. We found that 38.2 % (26/68) of water samples were positive, Acanthamoeba was 13.2% (9/68) whilst Naegleria was 35.3% (24/68). Contamination by free-living ameba in natural hot springs may pose a significant health risk to people who use such water for recreation activities.

Acanthamoeba↗

PubMed2005

Spa, springs and safety.

Natural mineral water has long been used worldwide for bathing and health purposes. At present, Thailand is famous for health spas and natural hot springs among local people and tourists. Due to possible risks of exposure to harmful agents, we studied hazardous pollutants at 57 natural hot springs from 11 provinces in northern, central, eastern and southern Thailand. Pathogenic, free-living amebae of the genera Naegleria and Acanthamoeba, which can cause central nervous system infection, were found in 26.3% (15/57) and 15.8% (9/ 57), respectively. Dissolved radon, a soil gas with carcinogenic properties, was present in nearly all hot springs sites, with concentration ranging from 0.87-76,527 Becquerels/m3. There were 5 water samples in which radon concentration exceeded the safety limit for drinking. Legionella pneumoniphila (serogroups 1, 3, 5, 6, 7 10 and 13) were found in samples from 71.9% (41/57) of studied sites. Because spas and natural springs are popular tourist attractions, health authorities should be aware of possible hazards and provide tactful measures and guidelines to ensure safety without causing undue alarm to foreign and Thai tourists.

Acanthamoeba↗

PubMed2005

Protozoal contamination of water used in Thai frozen food industry.

This study evaluated the prevalence of contamination of water that was used for food preparation. Since protozoal cysts can be found in small numbers in water, 1,000 liters of either untreated or treated water were filtered through activated carbon block filters (1 microm nominal porosity). Identification of protozoa was performed using specific monoclonal antibodies against Giardia and Cryptosporidium parasites followed by fluorescence microscopy. Twelve of 20 untreated water samples (60%) were found to be contaminated by Giardia cysts, with an average of 53.33 cysts/1,000 liters (geometric mean 39.43), whilst 7 samples (35%) were contaminated by Cryptosporidium oocysts, with an average of 28.57 oocysts/1,000 liters (geometric mean 26.92). Three samples of untreated water (15%) were positive for both organisms. In contrast, none of the treated water samples were contaminated.

Animals↗

PubMed2005

Comparison of five DNA extraction methods and optimization of a b1 gene nested PCR (nPCR) for detection of Toxoplasma gondii tissue cyst in mouse brain.

Toxoplasmosis, caused by Toxoplasma gondii, is an important parasitic disease worldwide. Different techniques have been developed for T. gondii detection. At present, polymerase chain reaction (PCR) has been widely used. However, PCR for identifying T. gondii remains unsatisfactory in many laboratories because of lack of standardization and variations in efficiency. In the present study, we optimized a nested PCR protocol (n-PCR) in order to compare the amplification of T. gondii DNA, after being extracted from mouse brain by five different DNA extraction methods including phenol chloroform, QIAamp DNA minikit, Genomic DNA purification kit and Chelex with or without proteinase K. All DNA extraction methods were able to extract DNA from a single tissue cyst from mouse brain. However, among the five DNA extraction methods, the Chelex without proteinase K appeared to be the most rapid and easiest.

Animals↗

PubMed2004

PCR technique for detecting Toxoplasma gondii in animal amniotic fluid.

The goal of diagnosing congenital toxoplasmosis is early detection of maternofetal transmission, for early treatment to prevent unwanted sequelae. Polymerase chain reaction (PCR) is a method used recently for detecting toxoplasmosis during pregnancy. Amniotic fluid is a the clinical specimen used, since it provides a rapid, simple and safe method to obtain accurate results. The advantages of the PCR technique are high sensitivity, specificity and positive predictive value compared with other laboratory methods. To determine the sensitivity, specificity and lower detection limits in our laboratory, amplification of the B1 gene by nested PCR was performed on Toxoplasma gondii tachyzoites added to animal amniotic fluid samples. From 48 samples, our technique detected T. gondii in 30 out of 41 positive samples, and gave negative results for all the negative samples. The sensitivity for this nested PCR was 73%, the specificity was 100%, and the efficiency of the test was 77.1%. The nested PCR technique is recommended as a diagnostic method for detecting T. gondii in suspected congenital toxoplasmosis animals.

Amniotic Fluid↗

PubMed2003

Pathologic study of acute toxoplasmosis in experimental animals.

We studied the pathology of acute toxoplasmosis in experimental mice inoculated with RH strain tachyzoites of Toxoplasma gondii. All died from severe disseminated toxoplasmosis involving the liver, spleen and pancreas. Pathological features of acute toxoplasmosis in susceptible mice could be regarded as an excellent model for acute reactivation of Toxoplasma in the immunosuppressed host.

Acute Disease↗

PubMed2003

Toxoplasma gondii antibody in Thai cats and their owners.

Humans are thought to acquire Toxoplasma infection by three major routes: ingesting food and water contaminated with oocysts from cat excreta, consumption of under-cooked infected meat, and transplacental transfer. Congenital clinical toxoplasmosis in the newborn indicating definite transplacental transmission had been reported in Thailand, whilst studies concerning infection due to the other two routes were inconclusive. Since the way domestic cats live and eat and also the eating behavior of Thai people differ from those in the West, we conducted a sero-epidemiological study of T. gondii in cats and their owners in Bangkok metropolitan area. Among 327 humans, the prevalence of Toxoplasma antibody was 6.4% and in 315 cats it was 7.3%. These relatively low prevalence rates may result from the predominantly well-cooked fish and rice diet of stray cats, which congregate in temples where they are fed. Toxoplasma antibody seropositive was associated with living in close proximity to seropositivity cats [OR (95% CI) = 5.43 (1.28-23.04); p=0.01]. Risks were increased in and around temples, particularly if courtyards were of earth or grass, suggesting ground temperature was an important determinant of oocyst survival.

Adolescent↗

PubMedDate not supplied

Plasmodium falciparum: effect of anti-malarial drugs on the production and secretion characteristics of histidine-rich protein II.

Plasmodium falciparum histidine-rich protein II (HRP2) is one of the best documented malaria proteins. However, little is known about the development of HRP2 concentrations under the influence of anti-malarial drugs. HRP2 levels were determined in cell medium mixture, cellular compartment, and in culture supernatant using a double-site sandwich ELISA specific for HRP2. Characteristic increases in the overall HRP2 levels were found during the later ring and the trophozoite stages. Throughout the later schizont development, rupture, and reinvasion, however, the HRP2 levels remained comparatively stable. When the cultures were exposed to serial dilutions of anti-malarial drugs, a distinct inhibition of HRP2 production was seen with increasing concentrations of drugs, resulting in sigmoid dose-response curves, similar to those obtained from conventional drug sensitivity assays. HRP2 therefore allows for a very accurate estimation of parasite development and its inhibition and may therefore be ideally suited for use in drug sensitivity or bioassays.

Animals↗