MyMedR

Displaying all 8 publications

Abstract:

Sort:

Biophotonic effect of diode laser irradiance on tensile strength of diabetic rats

Lau PS, Bidin N, Krishnan G, Nassir Z, Bahktiar H

J Cosmet Laser Ther, 2015 Apr;17(2):86-9.
PMID: 25260140 DOI: 10.3109/14764172.2014.968587

Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers-0.1 and 0.5 W/cm(2)-and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing.
Accuracy of Modified Checklist for Autism in Toddlers (M-CHAT) in detecting autism and other developmental disorders in community clinics

Toh TH, Tan VW, Lau PS, Kiyu A

J Autism Dev Disord, 2018 01;48(1):28-35.
PMID: 28866856 DOI: 10.1007/s10803-017-3287-x

This study determined the accuracy of Modified Checklist for Autism in Toddlers (M-CHAT) in detecting toddlers with autism spectrum disorder (ASD) and other developmental disorders (DD) in community mother and child health clinics. We analysed 19,297 eligible toddlers (15-36 months) who had M-CHAT performed in 2006-2011. Overall sensitivities for detecting ASD and all DD were poor but better in the 21 to <27 months and 27-36-month age cohorts (54.5-64.3%). Although positive predictive value (PPV) was poor for ASD, especially the younger cohort, positive M-CHAT helped in detecting all DD (PPV = 81.6%). This suggested M-CHAT for screening ASD was accurate for older cohorts (>21 months) and a useful screening tool for all DD.
Fulltext Case report: Aseptic splenic abscesses in childhood-onset systemic lupus erythematosus

Sritharan S, Lau PS, Manan K, Mohan A

Front Pediatr, 2023;11:1214551.
PMID: 37520056 DOI: 10.3389/fped.2023.1214551

BACKGROUND: Systemic lupus erythematosus (SLE) can involve any organ system and cause a wide range of manifestations. Noninfectious inflammatory lesions termed aseptic abscesses have been reported in some autoimmune and autoinflammatory conditions but not in childhood-onset SLE. In this report, we highlight the unusual finding of occult splenic abscesses in two children diagnosed with SLE who had no evidence of concomitant infection.
CASE PRESENTATION: An 8-year-old and an 11-year-old were admitted separately to the hospital with fever for 7 and 14 days, respectively. In the younger child, a generalized rash preceded the fever. Both had been well, with no significant past medical history prior to the onset of the illness. In both girls, abdominal ultrasonography showed multiple small hypoechoic lesions suggestive of abscesses scattered throughout the spleen. Their C-reactive protein and blood cultures were negative, and symptoms persisted despite intravenous antibiotics. Fulfilling the clinical and immunologic criteria for diagnosis, both were ultimately diagnosed with childhood-onset SLE. Rapid recovery of symptoms and complete resolution of the abscesses ensued with corticosteroids and immunosuppressive therapy.
CONCLUSIONS: These two cases suggest that aseptic splenic abscesses may occur in childhood-onset SLE. Autoimmune conditions such as SLE should be included in the differential diagnosis of children with occult splenic abscesses.
In Vitro Functional Characterisation of Cytochrome P450 (CYP) 2C19 Allelic Variants CYP2C19*23 and CYP2C19*24

Lau PS, Leong KV, Ong CE, Dong AN, Pan Y

Biochem Genet, 2017 Feb;55(1):48-62.
PMID: 27578295 DOI: 10.1007/s10528-016-9771-8

Cytochrome P450 (CYP) 2C19 is essential for the metabolism of clinically used drugs including omeprazole, proguanil, and S-mephenytoin. This hepatic enzyme exhibits genetic polymorphism with inter-individual variability in catalytic activity. This study aimed to characterise the functional consequences of CYP2C19*23 (271 G>C, 991 A>G) and CYP2C19*24 (991 A>G, 1004 G>A) in vitro. Mutations in CYP2C19 cDNA were introduced by site-directed mutagenesis, and the CYP2C19 wild type (WT) as well as variants proteins were subsequently expressed using Escherichia coli cells. Catalytic activities of CYP2C19 WT and those of variants were determined by high performance liquid chromatography-based essay employing S-mephenytoin and omeprazole as probe substrates. Results showed that the level of S-mephenytoin 4'-hydroxylation activity of CYP2C19*23 (V max 111.5 ± 16.0 pmol/min/mg, K m 158.3 ± 88.0 μM) protein relative to CYP2C19 WT (V max 101.6 + 12.4 pmol/min/mg, K m 123.0 ± 19.2 μM) protein had no significant difference. In contrast, the K m of CYP2C19*24 (270.1 ± 57.2 μM) increased significantly as compared to CYP2C19 WT (123.0 ± 19.2 μM) and V max of CYP2C19*24 (23.6 ± 2.6 pmol/min/mg) protein was significantly lower than that of the WT protein (101.6 ± 12.4 pmol/min/mg). In vitro intrinsic clearance (CLint = V max/K m) for CYP2C19*23 protein was 85.4 % of that of CYP2C19 WT protein. The corresponding CLint value for CYP2C19*24 protein reduced to 11.0 % of that of WT protein. These findings suggested that catalytic activity of CYP2C19 was not affected by the corresponding amino acid substitutions in CYP2C19*23 protein; and the reverse was true for CYP2C19*24 protein. When omeprazole was employed as the substrate, K m of CYP2C19*23 (1911 ± 244.73 μM) was at least 100 times higher than that of CYP2C19 WT (18.37 ± 1.64 μM) and V max of CYP2C19*23 (3.87 ± 0.74 pmol/min/mg) dropped to 13.4 % of the CYP2C19 WT (28.84 ± 0.61 pmol/min/mg) level. Derived from V max/K m, the CLint value of CYP2C19 WT was 785 folds of CYP2C19*23. K m and V max values could not be determined for CYP2C19*24 due to its low catalytic activity towards omeprazole 5'-hydroxylation. Therefore, both CYP2C19*23 and CYP2C19*24 showed marked reduced activities of metabolising omeprazole to 5-hydroxyomeprazole. Hence, carriers of CYP2C19*23 and CYP2C19*24 allele are potentially poor metabolisers of CYP2C19-mediated substrates.
Photobiomodulation therapy on wound treatment subsequent to Q-switched Nd: YAG laser tattoo removal in rat model

Imrigha NAA, Bidin N, Lau PS, Musa N, Zakaria N, Krishnan G

J Biophotonics, 2017 Oct;10(10):1287-1291.
PMID: 28464516 DOI: 10.1002/jbio.201600295

Q-switched Nd: YAG laser is the most effective laser for tattoo removal. Photobiomodulation (PBM) therapy is an alternative method applied to accelerate the wound healing. This paper investigated the effects of PBM therapy using 808 nm diode laser on tattooed skin after laser tattoo removal. Forty-five rats were selected and tattooed with black ink on their dorsal, and then distributed into three groups. G0 was received non-laser irradiation. G1 was treated by laser tattoo removal using 1064 nm with energy density of 3.4 J/cm2 without PBM therapy, while G2 was treated daily with PBM therapy using 808 nm diode laser of 5 J/cm2 after a single session of laser tattoo removal. The effects of tattoo removal and healing progress of the wound were analyzed using histological studies. Findings showed 808 nm laser promotes the healing process through enhancing epithelialization and collagen deposition. Moreover, PBM therapy stimulated immune cells to improve phagocytosis process for removing the tattoo ink fragments effectively. The PBM therapy treated group was capable of improving the healing process and increasing the quality of skin following the laser tattoo removal. It was also found that stimulation of cellular function by PBM therapy increased tattoo clearance efficiency.
Fulltext Invasive Salmonella infections among children in Bintulu, Sarawak, Malaysian Borneo: a 6-year retrospective review

Mohan A, Munusamy C, Tan YC, Muthuvelu S, Hashim R, Chien SL, et al.

BMC Infect Dis, 2019 Apr 18;19(1):330.
PMID: 30999894 DOI: 10.1186/s12879-019-3963-x

BACKGROUND: Invasive Salmonella infections result in significant morbidity and mortality in developing countries. In Asia, typhoid and paratyphoid fever are reported to be the major invasive Salmonella infections, while invasive non-typhoidal Salmonella (iNTS) infections are believed to be uncommon. Data from Sarawak, in Malaysian Borneo, are limited.
METHODS: A retrospective study identifying all children aged
Fulltext Detection of spleen abscesses facilitates diagnosis of melioidosis in Malaysian children

Mohan A, Manan K, Tan LS, Tan YC, Chin ST, Ahmad R, et al.

Int J Infect Dis, 2020 Sep;98:59-66.
PMID: 32535300 DOI: 10.1016/j.ijid.2020.06.025

OBJECTIVES: Melioidosis is associated with extremely high case fatality ratios. The aim of this study was to determine whether detection of abdominal visceral abscesses can facilitate diagnosis of melioidosis in children.
METHODS: We conducted a retrospective analysis of all children who had liver and/or spleen abscesses on abdominal ultrasonography admitted to Bintulu Hospital in Sarawak, Malaysia, from January 2014 until December 2018.
RESULTS: Fifty-three children had liver and/or spleen abscesses. Spleen abscesses were present in 48 (91%) cases; liver abscesses in 15 (28%). Melioidosis was confirmed by culture in 9 (17%) children; small occult splenic abscesses were present in all cases. In 78% of these cases, the lesions were detected before any positive culture (or serology) results were available. Four (8%) children had bacteriologically-confirmed tuberculosis. Two (4%) had Staphylococcus aureus infection. Of the remaining 38 (72%) culture-negative cases, 36 (95%) had clinical and imaging characteristics similar to that of children with culture-confirmed melioidosis and improved with empirical melioidosis antibiotic therapy.
CONCLUSIONS: A large number of children in Bintulu Hospital in Sarawak, Malaysia, were found to have spleen abscesses. Melioidosis was the most common etiology identified in these children. Abdominal ultrasonography is extremely useful in facilitating the diagnosis of pediatric melioidosis.
Fulltext Fine-needle aspiration to improve diagnosis of melioidosis of the head and neck in children: a study from Sarawak, Malaysia

Mohan A, Podin Y, Liew DW, Mahendra Kumar J, Lau PS, Tan YY, et al.

BMC Infect Dis, 2021 Oct 15;21(1):1069.
PMID: 34654392 DOI: 10.1186/s12879-021-06754-9

BACKGROUND: Melioidosis, the infection caused by Burkholderia pseudomallei, is associated with a high case fatality rate, due in part to difficulties in clinical recognition and diagnostic confirmation of the disease. Although head and neck involvement is common in children, specific disease manifestations differ between geographic regions. The aim of this study was to provide a detailed description of melioidosis of the head and neck among children in Sarawak, Malaysia, and determine if fine-needle aspiration of suspected head or neck lesions could improve melioidosis diagnosis.
METHODS: We conducted a retrospective descriptive study of all children aged