Evaluation of the sensitivities of DNA extraction and PCR methods for detection of Giardia duodenalis in stool specimens

Sensitivities of DNA extraction methods and PCR methods for Giardia duodenalis were evaluated. A combination of the most sensitive methods, i.e., FTA filter paper and a PCR protocol using RH11/RH4 and GiarF/GiarR primers, showed no significant differences compared to immunofluorescence assay in terms of their sensitivities and specificities.

Botulinum toxin B-induced mouse model of keratoconjunctivitis sicca

PURPOSE

To develop a mouse model of human chronic dry eye (keratoconjunctivitis sicca [KCS]).

METHODS

Under direct visualization with an operating microscope, CBA/J mice received a transconjunctival injection of saline or 1.25, 5, or 20 milliunits (mU) of botulinum toxin B (BTX-B) into the lacrimal gland. The mice were either left unstressed or were subjected to an air blower for 5 h/d, 5 d/wk in fixed temperature and humidity conditions. Tear production and corneal fluorescein staining were evaluated in all groups before injection and at several time points after. Tear production was measured with phenol red-impregnated cotton threads. Corneal fluorescein staining was photographed under cobalt blue light with a digital camera fitted with a macro lens.

RESULTS

BTX-B-injected mice displayed significantly decreased tear production until the 4-week time point. Throughout all time points, the addition of environmental blower stress did not appear to alter tear production significantly. Linear regression models, used to evaluate the effects of various doses of BTX-B on tear production, showed that doses higher than 1.25 mU did not provide significantly different outcomes. After 3 days, saline-injected mice showed no corneal staining, whereas BTX-B-injected mice displayed various amounts of staining. At the early time point (day 3), there did not appear to be an additional effect of the blower on corneal fluorescein staining. However, at 1, 2, and 4 weeks, the blower stress appeared to increase the amount of corneal fluorescein staining at each BTX-B dose, although not significantly. Furthermore, at 8 to 10 weeks, in the BTX B-injected groups, corneas had persistent staining, even though tear production had already returned to normal levels. Histopathologic analyses revealed no inflammatory cell infiltration of the stroma or acini of the lacrimal glands and conjunctivae of both saline-injected and BTX-B-injected animals.

CONCLUSIONS

Intralacrimal gland injection of BTX-B resulted in persistent corneal fluorescein staining within 3 days, and a significant decrease in aqueous tear production that persisted for 1 month. Intralacrimal gland injection of BTX-B suppressed lacrimation, thereby establishing a dry eye state. This animal model could be a useful tool for investigating the pathogenesis of the chronic condition KCS in humans.

Teaching medical ethics: Phramongkutklao College of Medicine's model

BACKGROUND

Third-year (first preclinical year) Royal Thai Army (RTA) medical cadets were exposed to a rural community in a community medicine field activity. The poor, kind rural people gave good conditions for student's professional development and empathy.

OBJECTIVES

To report a community medicine field work activity for professional development of the RTA medical school.

MATERIAL AND METHOD

Descriptive analysis on two occasions to evaluate the third-year RTA medical cadets' impressions immediately after the community medicine field activity in a rural area in central Thailand and one year later using baseline scores of cadets' impressions against our institute's objectives.

RESULTS

At the end of the field work, 90.9% of the cadets reported they achieved several institute objectives. The four most frequent mentioned were ethical development (70.6%), professionalism (84.3%), human relationship & communication skills (92.2%), and capability to work in the cmmunity (64.7%). Furthermore, RTA medical cadets rated the staff as good role models (51%).

CONCLUSION

The community field work course provided a good environment for the third year medical cadets in building morality and professional development to be good doctors.

Roles of the Royal Thai Army Medical Department in supporting the country to fight against HIV/AIDS: 18 years of experience and success

Human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) are global major public health problems and have a major impact on social and economic development. Thailand has been affected from HIV/AIDS epidemic since the first AIDS case was reported in 1984, making the cumulative number of reported AIDS cases more than 160,000 and estimated HIV-infected people more than 1,000,000 by the end of 2004 and more than 300,000 of them are dead. There has been a strong national response to this scourge by multi-sectoral cooperation and many evidences show Thailand's success in HIV/ AIDS control. The Royal Thai Army Medical Department has played an important role in supporting the country to fight against HIV/AIDS since 1987 by providing HIV/AIDS education to army personnel, families and civilians. It has established the sero-surveillance system in young Thai men entering the army since 1989 and behavioral surveillance system since 1991. The other important activities have been training of personnel, care and research, especially for an HIV vaccine. It facilitates the research that the army conscripts which represent young Thai men are used as samples. The experience of the RTA Medical Department and the civil-military alliance against HIV/AIDS of Thailand are good lessons for other developing countries to learn and adopt the strategies in the battle against HIV/AIDS.

Dietary behaviors and nutritional status of adolescents in a remote rural area of Thailand

INTRODUCTION

Nutritional status among adolescents is an important health indicator. The up-to-date information about nutritional status and food consumption pattern in the remote rural area is required for the effective public health intervention in the rural area of the country. The present study aimed to demonstrate the prevalence of malnutrition, eating behavior and nutritional knowledge among secondary school students in a remote rural area in Thailand.

MATERIAL AND METHOD

Body weight and height data were collected from 298 secondary school students for nutritional status calculation using the Institute of Nutrition Research, Mahidol University, INMU-Thaigrowth program. Eating behavior and nutritional knowledge were observed by self-administrated questionnaires.

RESULTS

The prevalence low height-for-age (<-2SD) 6.1% and it was 0.7% for low weight-for-height (<-2SD). Fruits (69%) and vegetables (79.4%) consumptions were in the high level. The authors found that the students always consumed commercial snacks especially salted chips more often than regular Thai dessert (74.0% VS 52.3%). The inappropriate behavior found in the present study included always drinking caffeine beverage (43.5%), always drinking alcoholic beverage (6.5%) and always consuming instant noodles (64.4%).

CONCLUSION

The prevalence of malnutrition was low among this population. The studied population had a fair knowledge about nutrition. The authoes found that regular consumption of highly commercialized snack products especially salted chips and instant noodles were at a high level in this remote rural area of Thailand. The pattern of nutritional problems in Thailand may have changed in which a public health program for children in rural areas of the country should recognize this transition.

The natural history of HIV-1 infection in young Thai men after seroconversion

The natural history and progression of HIV-1 infection in Thailand and other developing countries in Asia and Africa have not been well defined. Nevertheless, valid data are needed to evaluate the effects of interventions, which are designed to delay progression. We evaluated the progression to AIDS and death in 235 men who seroconverted during their 2 years of service in the Royal Thai Army. The men were conscripted at age 21 and seroconverted within a 6-month window during follow-up while in the military. The seroconverters were matched with men who were seronegative when discharged. Of the HIV-positive men, 156 (66.4%) were alive, 77 (32.8%) had died, and 2 (0.8%) could not be located 5-7 years after their seroconversion and discharge from the military. The 5-year survival rate was 82.3%; the median times to clinical AIDS and a CD4 cell count of <200/microL was 7.4 years and 6.9 years, respectively. The mortality rate was 56.3 deaths per 1000 patient-years for HIV-positive men and 6.1 deaths per 1000 patient-years for HIV-negative men. Our data suggest a more rapid progression to AIDS and death after HIV-1 infection in young men in Thailand than has been reported for similarly aged cohorts in developed countries.

Transmission of Enterocytozoon bieneusi genotype a in a Thai orphanage

A cross-sectional study of Enterocytozoon bieneusi infection in children who lived in an orphanage in Bangkok, Thailand was conducted in April 2003. Two hundred ninety stool specimens were collected and examined under light microscopy after staining with gram-chromotrope. Confirmation of E. bieneusi was done using transmission electron microscopy. Of 290 samples, 12 (4.1%) were positive for E. bieneusi. Genotypic characterization of 10 E. bieneusi showed that all were genotype A, which might indicate the same source of infection. Multivariate analysis showed that orphans who were 12-23 months old, girls, and living in one particular house were independently associated with E. bieneusi infection. Our study suggests that E. bieneusi infection in this orphanage might be transmitted person to person.

Dyslipidemia in Thai rural adults

The present study aimed to determine the prevalence of dyslipidemia in adults in a rural area of Thailand. Random sampling was conducted in 443 volunteers, 187 males and 256 females, aged > or = 35 years in Chachoengsao Province. After a 12-hour fast, the blood was drawn for the analysis of total cholesterol, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol. Mean serum lipids of cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were 207.79 +/- 46.98, 117.26 +/- 36.59, 50.53 +/- 2.14 and 201.21 +/- 131.07 mg/dL, respectively. Nineteen percent of them had cholesterol > or = 240 mg/dL and 10% had LDL cholesterol > or = 160 mg/dL. Seven percent had HDL cholesterol < or = 35 mg/dL. However, LDL/HDL cholesterol ratios > 5, were found in only 0.9%. In conclusion, the prevalence of dyslipidemia was high in rural Thai adults. Further surveillance in this population is essential in verifying the impact of dyslipidemia as a risk of cardiovascular disease in rural Thai adults.

Prevalence of etiologic bacteria and beta-lactamase-producing bacteria in acute and chronic maxillary sinusitis at Phramongkutklao Hospital

BACKGROUND

To date, there is an increasing trend of prescribing antibiotics that cover beta-lactamase-producing bacteria as the first line drug for sinusitis patients in Thailand This practice dose not only increases the treatment cost but might also induce resistance to antimicrobial agents.

OBJECTIVE

To determine the prevalence of the pathogenic bacteria in acute and chronic maxillary sinusitis as well as the prevalence of beta-lactamase-producing bacteria.

MATERIAL AND METHOD

The maxillary aspiration fluid specimens of 52 acute and chronic sinusitis patients at Phramongkutklao Hospital, Bangkok, Thailand during May 2002-May 2003, were collected. Aerobic and anaerobic cultures were performed and the beta-lactamase activities of isolated bacteria were determined.

RESULTS

Of 58 specimens, 44 (75.9%) and 14 (24.1%) specimens were collected from acute and chronic maxillary sinusitis patients, respectively. Of 44 specimens of acute maxillary sinusitis, the predominant isolates were Haemophilus influenzae (13, 29.5%), Streptococcus pneumoniae (4, 9%), Streptococcus viridan (4, 9%), and Klebsiella pneumoniae (4, 9%). 6 (13.6%) of them were beta-lactamase-producing bacteria. Of 14 specimens of chronic maxillary sinusitis, the predominant isolates were Pseudomonas aeruginosa (3, 16.6%), Staphylococcus spp (3, 17.5%) and Streptococcus spp. (2, 11.6%). 1 (7.1%) Haemophilus influenza isolate from this group was beta-lactamase-producing bacteria. The percentage of anaerobe was 8.9%, 23.3% for acute and chronic maxillary sinusitis, respectively.

CONCLUSION

The present study was indicated that the common organisms in acute maxillary sinusitis were Haemophilus influenzae and Streptococcus pneumoniae, Streptococcus viridians which were similar to a previous study. But the authors found an increased prevalence of anaerobe bacteria in acute maxillary sinusitis and also found beta-lactamase-producing bacteria, 21.4% Hemophilus influenzae less than the previous studies (which found beta-lactamase-producing bacteria around 50% to 70%). The authors found 23.3% anaerobe bacteria in the chronic maxillary sinusitis, less than the previous studies, and the authors also found 8.9% anaerobe in acute maxillary sinusitis.

Evaluation of DNA extraction and PCR methods for detection of Enterocytozoon bienuesi in stool specimens

An evaluation of the sensitivities of three DNA extraction methods, i.e., FTA filter paper, a QIAamp stool mini kit, and a conventional phenol-chloroform method, by using specimens with known concentrations of Enterocytozoon bieneusi spores was performed. FTA filter paper and the QIAamp stool mini kit were the most sensitive methods, which could detect E. bieneusi in specimens with a concentration of 800 spores/ml. We also compared five previously described PCR methods that use five different primer pairs for the detection of E. bieneusi and showed that MSP3-MSP4B and EBIEF1-EBIER1 were the most sensitive primers. Although both sets of primers showed the same sensitivity, using the MSP3-MSP4B primers can directly provide genotypic information by sequencing. A blinded diagnostic test to compare PCR and light microscopy methods for the detection of E. bieneusi in stool specimens was also conducted. The use of FTA filter paper for DNA extraction together with the PCR method using the primer pair MSP3-MSP4B showed 100% sensitivity and 100% specificity for the detection of E. bieneusi in stool specimens, while the light microscopy method gave a sensitivity of 86.7% and a specificity of 100%.

Evidence of waterborne transmission of Blastocystis hominis

A cross-sectional study was performed in February 2001 to evaluate the prevalence and risk factors of Blastocystis hominis infection in army personnel who resided in an army base in Chonburi, Thailand. A total of 904 army personnel were enrolled in this study. Short-term in vitro cultivation was used to detect B. hominis in stool samples. In this population, B. hominis was the parasite most frequently found, and was identified in 334 of 904 stool specimens (36.9%). A significant association between B. hominis infection and symptoms was identified that might emphasize the role of B. hominis as a human pathogen. After adjustment for potential confounders, significantly increased risk of being infection with B. hominis was associated with being a private, working in a specific unit, and consuming unboiled drinking water. Thus, waterborne transmission of B. hominis infection was indicated at this army base. However, other modes of transmission cannot be ruled out.

In-vitro cultivation: a sensitive method for detecting Blastocystis hominis

Currently, the detection of human infection with Blastocystis hominis is usually based on the examination under a light microscope of faecal samples, either directly, as 'simple smears', or after some form of concentration. Whether short-term, in-vitro cultivation would increase the sensitivity of such detection remains a matter of controversy. Over 900 fresh stool specimens, from soldiers in the Royal Thai Army, were each checked for the parasite using three methods: simple smears; formalin-ethyl-acetate concentration; and cultivation in Jones' medium. Although 334 of the samples were found to be culture-positive, the parasites were only detected in 142 of the simple smears, and faecal concentration led to an even lower sensitivity (64 positive samples). In-vitro cultivation does seem worthwhile in the detection of B. hominis carriage in field studies.

Prevalence of Blastocystis hominis carriage in Thai army personnel based in Chonburi, Thailand

Blastocystis hominis is one of the most common intestinal parasites found in humans. The prevalence of B. hominis carriage in personnel who worked in the First Army Support Command, Chonburi, Thailand, was determined. Forty-four percent of 616 stool samples were positive for B. hominis using both simple smear and concentration (Formalin/ethyl acetate) techniques. The usefulness of the concentration technique in the diagnosis of B. hominis has been confirmed. Of 272 positive specimens, 75% were detected by simple smear and 25% were additionally identified by the concentration technique. The prevalence of B. hominis carriage was highest among the privates who had lived longest in this command. This finding indicates that they might have acquired B. hominis during their stay at this base. The significantly high prevalence of B. hominis carriage was found in the Ordnance Ammunition Battalion. In this battalion, privates who had education lower than the secondary school level had significantly greater risk of B. hominis carriage.

Trends in long-term survival following liver resection for hepatic colorectal metastases

OBJECTIVE

To examine trends in outcomes of patients undergoing resection at a single tertiary care referral center over a 16-year period.

SUMMARY BACKGROUND DATA

Hepatic resection is considered the treatment of choice in selected patients with colorectal metastasis confined to the liver. Although a variety of retrospective studies have demonstrated improvements in short-term outcomes in recent years, changes in long-term survival over time are less well-established.

METHODS

Data from 226 consecutive patients undergoing potentially curative liver resection for colorectal metastases between 1984 and 1999 were analyzed. Actuarial survival rates related to prognostic determinants were analyzed using the log-rank test.

RESULTS

The median survival for the entire cohort was 46 months, with 5- and 10-year survival rates of 40% and 26% respectively. Ninety-three patients operated on between 1984 and 1992 were found to have an overall survival of 31% at 5 years, compared to 58% for the 133 patients operated on during the more recent period (1993-1999). Both overall and disease-free survival were significantly better in the recent time period compared with the earlier period on both univariate and multivariate analyses. Other independent factors associated with improved survival included number of metastatic tumors < or = 3, negative resection margin, and CEA < 100. Comparisons were made between time periods for a variety of patient, tumor and treatment-related factors. Among all parameters studied, only resection type (anatomical versus nonanatomical), use of intraoperative ultrasonography, and perioperative chemotherapy administration differed between the early and recent time periods.

CONCLUSIONS

Long-term survival following liver resection for colorectal metastases has improved significantly in recent years at our institution. Although the reasons for this survival trend are not clear, contributing factors may include the use of newer preoperative and intraoperative imaging, increased use of chemotherapy, and salvage surgical therapy.

The validity of the Medisafe self-monitoring blood glucose system

Self-monitoring blood glucose (SMBG) meters are widely used in the management of diabetes. The new SMBG meter Medisafe, which is based on the optoelectric colorimetry method, has been introduced. The objective of this study was to validate the Medisafe SMBG meters in comparison with the reference autoanalyzer (Hitachi 717) and to assess the repeatability of the instrument as well as variations of tip replacement. Samples of capillary and venous blood from 299 patients were tested. The correlation coefficients between the Medisafe-measured capillary and venous blood glucose levels and the reference autoanalyzer venous plasma glucose levels were 0.976 and 0.975, respectively. The range of differences from the reference value was examined; only 4% was in excess of +/- 20% of the reference laboratory value, and more than 40% of the values were within 5% of the reference laboratory value. Moreover, repeatability of the Medisafe capillary blood samples measured in three patients with three different blood glucose levels was determined. The coefficients of variation of blood glucose values are within 5%. In addition, the results of mean and SEM from each replication in three patients and glucose measurement from different lots of tips showed no significant difference (p > 0.05). It is concluded that the Medisafe SMBG meter has shown good results in terms of validity and repeatability. Furthermore, it provides safety from blood contamination, which is recommended in countries with a high prevalence of human immunodeficiency virus.

Transmission of intestinal blastocystosis related to the quality of drinking water

A cross-sectional study was performed to evaluate the risk factors of Blastocystis hominis infection in the Thai army population of the 11th Infantry Division, Chachoengsao Province, Thailand. 201 army personnel and their family members were enrolled in this study. Intestinal parasitic infections in this population were assessed by stool examination using simple smear, formalin/ether technique and Kato-thick smear. Approximately one third of the specimens were positive for one or more intestinal parasites. With the prevalence of 21.9%, B. hominis was the most common intestinal parasite found in this population. Our data indicated that blastocystosis in this army population was significantly linked to the quality of drinking water. After being adjusted for potential confounders, consuming neither filtered nor boiled water was independently associated with blastocystosis.