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Recent Submissions
Adaptation of archival egg-cultured Orientia tsutsugamushi to L929 mammalian cells enables persistent qPCR-detectable growth
(2025-01-01) Rosli S.N.Z.; Dimeng S.R.; Munawar W.A.S.W.A.; Hendri N.A.M.; Zahidi J.M.; Yong T.B.; Hashim R.; Abdad M.Y.; Ahmad N.; Ramli S.R.; Rosli S.N.Z.; Mahidol University
Rickettsial infections are a leading cause of febrile illness in Southeast Asia and Malaysia, although they are often underreported. Rickettsial pathogens largely fall within the genera Rickettsia and Orientia and classified within the Rickettsiaceae family. In Malaysia, scrub typhus, caused by Orientia tsutsugamushi, is the most frequently reported rickettsial infection. Traditionally, rickettsial organisms have been isolated and cultured from embryonated eggs. However, this method is labor and skill intensive, has limited scalability, and requires specialized equipment, making it less accessible to many laboratories. An alternative approach is to use mammalian/amphibian/invertebrate cell culture as a host for rickettsial propagation. In this study, we evaluated the potential for culturing rickettsial pathogens previously adapted and maintained in embryonated eggs in mammalian cell lines. Two mammalian cell lines (Vero E6 and L929) were inoculated with rickettsial strains previously identified as O. tsutsugamushi (strains Karp [n=8], Kato [n=4], and Gilliam [n=2]). The presence of O. tsutsugamushi was assessed by quantitative qPCR at 14-day intervals. After 90 days of culture, only one of the fifteen isolates (GL94) showed evidence of propagation in L929 cells, whereas O. tsutsugamushi DNA remained below the qPCR detection limit in Vero E6 cells for all isolates tested. Most of the other isolates showed little to no growth, with some exhibiting the presence of other bacteria. The identification and morphology of GL94 were confirmed via transmission electron microscopy (TEM), followed by full-length 16S sequencing. This study highlights the challenges of transitioning rickettsial culture from embryonated eggs to mammalian cell cultures.
Frailty and Upper Gastrointestinal Surgery: Initial Findings from Thailand’s First Surgical Frailty Study
(2025-08-01) Gonggetyai G.; Techalertsuwan N.; Nampoolsuksan C.; Parakonthun T.; Swangsri J.; Methasate A.; Siriussawakul A.; Chaiwat O.; Srinonprasert V.; Gonggetyai G.; Mahidol University
Objective: Thailand’s aging population has led to an increase in elderly patients undergoing major surgery. Frailty is a key predictor of adverse surgical outcomes, but its impact in Thai patients remains underreported. This study aimed to determine the prevalence of frailty and its association with short-term postoperative outcomes among patients undergoing upper gastrointestinal (UGI) surgery. Materials and Methods: This prospective cohort study included all adult patients undergoing elective UGI surgery at Siriraj Hospital between May 2020 and November 2021. Preoperative frailty was assessed using the Thai Frailty Index (TFI), with scores >0.25 indicating frailty. Demographic data, surgical details, and postoperative outcomes — including complications and survival at 3, 6, and 12 months — were compared between frail and robust groups. Results: Among 56 patients (median age 61.5 years), 18 (32.1%) were classified as frail. Frail patients were significantly older and had poorer functional status and nutritional risk. Frail patients also underwent fewer resection procedures (61.1% vs 84.2%, p=0.001). While the overall complication rate did not differ significantly between groups (50.0% vs 47.4%; p=0.457), frail patients experienced higher rates of major complications (16.7% vs 10.5%; p=0.045) and non-surgical complications (33.3% vs 21.1%; p=0.044). Mortality was significantly higher in the frail group at 3, 6, and 12 months postoperatively (p=0.001, 0.003, 0.006 respectively). Conclusion: Frailty is common among Thai patients undergoing UGI surgery and is associated with worse short-term outcomes and higher postoperative mortality. Routine frailty screening using the TFI may improve preoperative risk stratification and perioperative care planning.
Biopolymeric Nanoparticles for the Sustainable Removal of Pharmaceutical and Dye Wastes
(2025-01-01) Gunaseelan D.J.; Sivakumar M.; Sundaram G.A.; Vaishali C.V.; Alagarsamy A.; Thillaichidambaram M.; Gunaseelan D.J.; Mahidol University
The presence of pharmaceutical and dye contaminants in aquatic wastewater has emerged as a serious environmental issue due to their persistence, bioaccumulation, and toxic nature. However, both wastewater treatment methods repeatedly decrease or completely remove these pollutants. In this chapter, biopolymeric nanoparticles show special attention as eco-friendly, biodegradable, and efficient alternatives for wastewater purification. The green synthesis of natural polymers such as chitosan, alginate, cellulose, and starch, these nanoparticles exhibit high surface area, tunable functional groups, and strong adsorption or catalytic capabilities from pollutant water. This chapter talks about how to make biopolymeric nanoparticles and change surface area and physicochemical properties, all designed to effectively remove pharmaceutical waste and synthetic dyes. It also explores recent advances in removal mechanisms—including adsorption/degradation and photo-degradation performance. Additionally, this chapter emphasises how these biopolymeric materials are safe for the environment, can be reused, and shows their potential for treating large amounts of wastewater. The integration of biopolymeric nanoparticles with green synthesis methods underscores their promise as next-generation solutions for combating water pollution in a system that promotes recycling and sustainability.
The Use of Therapeutic Drug Monitoring to Personalize Once-daily Intravenous Busulfan in Thai Pediatric Patients Underwent Hematopoietic Stem Cell Transplantation
(2025-08-01) Ratanatharathorn C.; Meeudompong U.; Ratanatharathorn C.; Sanpakit K.; Ratanatharathorn C.; Mahidol University
Objective: Therapeutic drug monitoring (TDM) for personalizing busulfan dosing in pediatric hematopoietic stem cell transplantation (HSCT) is recommended. The proportion of patients requiring dose adjustments and the frequency of achieving the target area under the time curve (AUC) was observed. Materials and Methods: This study included children who underwent once-daily intravenous busulfan-conditioning HSCT during October 2020 to April 2024. The initial busulfan dosage followed the European Medicines Agency nomogram, set between 3.2 and 4.8 mg/kg/day. Blood samples were collected to analyze pharmacokinetics and calculate AUC. Dose adjustments were made if AUC fell outside the target of 3,600 to 6,000 μMolar·min. Results: The study comprised 26 children. Dose adjustments for busulfan were performed in 17 patients (65.4%). Individual average AUCs ranged from 2,566.2 to 6,943.05 μMolar·min. Patients under 10 years had a higher likelihood of an out-of-range target AUC following dose adjustment compared to those aged ≥ 10 years (43.8% and 0%, respectively; P=0.023). A lower-than-target average AUC was significantly related to an earlier disease relapse compared to non-lower range AUCs (P<0.005). Conversely, higher AUCs did not correlate with busulfan-related side effects or treatment-related mortality. Conclusion: Our findings support TDM as a strategy to enhance the efficacy of once-daily intravenous busulfan in HSCT among Thai pediatric patients. TDM may help reduce the frequency of subtherapeutic exposures, which is associated with disease relapse. Patients under 10 years face more difficulties in achieving the target AUC, indicating the need for careful monitoring and dose adjustments in this age group.
Evaluation of Land Use Land Cover Changes in Nan Province, Thailand, Using Multi-Sensor Satellite Data and Google Earth Engine
(2023) Jiratiwan Kruasilp; Sura Pattanakiat; Thamarat Phutthai; Poonperm Vardhanabindu; Pisut Nakmuenwai
Land use and land cover (LULC) conversion has become a chronic problem in Nan province. The primary factors of changes are lacking arable land, agricultural practices, and agriculture expansion. This study evaluated the usefulness of multi-sensor Landsat-5 (LS5), Landsat-8 (LS8), Sentinel-1 (S1), and Sentinel-2 (S2) satellite data for monitoring changes in LULC in Nan province, Thailand during a 30-year period (1990-2019), using a random forest (RF) model and the cloud-based Google Earth Engine (GEE) platform. Information of established land management policies was also used to describe the LULC changes. The median composite of the input variables selection from multi-sensor data were used to generate datasets. A total of 36 datasets showed the overall accuracy (OA) ranged from 51.70% to 96.95%. Sentinel-2 satellite images combined with the Modified Soil-Adjusted Vegetation Index (MSAVI) and topographic variables provided the highest OA (96.95%). Combination of optical (i.e., S2 and LS8) and S1 Synthetic Aperture Radar (SAR) data expressed better classification accuracy than individual S1 data. Forest cover decreased continuously during five consecutive periods. Coverage of maize and Pará rubber trees rapidly expanded in 2010-2014. These changes indicate an adverse consequence of the established economic development promoted by industrial and export agriculture. The findings strongly support the use of the RF technique, GEE platform and multi-sensor satellite data to enhance LULC classification accuracy in mountainous area. This study recommended that certain informative and science-based evidence will encourage local policymakers to identify priority areas for land management and natural resource conservation.