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Alkaloids from the roots of Stichoneuron caudatum and their acetylcholinesterase inhibitory activities

Ramli RA, Lie W, Pyne SG

J Nat Prod, 2014 Apr 25;77(4):894-901.
PMID: 24606395 DOI: 10.1021/np400978x

Four new stichoneurine-type alkaloids, stichoneurines F and G (1-2) and sessilistemonamines E and F (3-4), have been isolated from the root extracts of Stichoneuron caudatum. The structures and relative configurations of these alkaloids have been determined by spectroscopic methods and molecular modeling experiments. Compounds 1-4 were tested for their acetylcholinesterase (AChE) inhibitory activities against human AChE. Compound 3 showed significant inhibitory activity with an IC50 value of 9.1±0.15 μM.
Synthesis, characterization, and morphology study of poly(acrylamide-co-acrylic acid)-grafted-poly(styrene-co-methyl methacrylate) "raspberry"-shape like structure microgels by pre-emulsified semi-batch emulsion polymerization

Ramli RA, Hashim S, Laftah WA

J Colloid Interface Sci, 2013 Feb 1;391:86-94.
PMID: 23123033 DOI: 10.1016/j.jcis.2012.09.047

A novel microgels were polymerized using styrene (St), methyl methacrylate (MMA), acrylamide (AAm), and acrylic acid (AAc) monomers in the presence of N,N'-methylenebisacrylamide (MBA) cross-linker. Pre-emulsified monomer was first prepared followed by polymerizing monomers using semi-batch emulsion polymerization. Fourier Transform Infrared Spectroscopy (FTIR) and (1)H Nuclear Magnetic Resonance (NMR) were used to determine the chemical structure and to indentify the related functional group. Grafting and cross-linking of poly(acrylamide-co-acrilic acid)-grafted-poly(styrene-co-methyl methacrylate) [poly(AAm-co-AAc)-g-poly(St-co-MMA)] microgels are approved by the disappearance of band at 1300 cm(-1), 1200 cm(-1) and 1163 cm(-1) of FTIR spectrum and the appearance of CH peaks at 5.5-5.7 ppm in (1)H NMR spectrum. Scanning Electron Microscope (SEM) images indicated that poly(St-co-MMA) particle was lobed morphology coated by cross-linked poly(AAm-co-AAc) shell. Furthermore, SEM results revealed that poly(AAm-co-AAc)-g-poly(St-co-MMA) is composite particle that consist of "raspberry"-shape like structure core. Internal structures of the microgels showed homogeneous network of pores, an extensive interconnection among pores, thicker pore walls, and open network structures. Water absorbency test indicated that the sample with particle size 0.43 μm had lower equilibrium water content, % than the sample with particle size 7.39 μm.
Fulltext Optimization of extraction conditions of gelatin from buffalo (Bubalus bubalis) skins using response surface methodology

Ramli RA, Mohamad Razali UH, Izzreen Mohd Noor NQ

Heliyon, 2023 Mar;9(3):e14367.
PMID: 36967921 DOI: 10.1016/j.heliyon.2023.e14367

The present study was to determine optimum conditions for gelatin extraction from the skin of buffalo (Bubalus bubalis) using response surface methodology. A central composite design (CCD) was performed to evaluate the effects of NaOH concentration ( X 1 ), pre-treatment time ( X 2 ), extraction temperature ( X 3 ), and extraction time ( X 4 ) on the yield (Y 1), gel strength (Y 2), and hydroxyproline content (Y 3) of the extracted gelatin. The optimal combination of the independent variables for a good gelatin yield with high gel strength and hydroxyproline content was found at X 1 (0.77 M), X 2 (5.08 h), X 3 (62.93 °C) and X 4 (11.62 h). The experimental values for Y 1 (16.91%), Y 2 (236.5 g), and Y 3 (41.4 g/100 g) were in good agreement with the predicted values of 17.87% yield, 237.80 g gel strength and 41.90 g/100 g of hydroxyproline content. Extraction temperature and extraction time were observed to be the most important factors that influenced the yield, gel strength, and hydroxyproline content, meanwhile pre-treatment time showed negative correlations with the yield and hydroxyproline content of the extracted gelatin. This study demonstrated that manipulation of specific parameters could improve extraction efficiency without compromising the quality of buffalo gelatin, thereby promoting it as an alternative source for gelatin production.
Comparison of Combination Between Ketamine and Parecoxib as Multimodal Preemptive Analgesia With Ketamine Alone for Elective Laparotomy

Ramli RA, Hassan WMNW, Ali S, Othman AK, Zaini RHM, Hassan MH

Asian J Anesthesiol, 2021 Dec 01;59(4):161-168.
PMID: 34979631 DOI: 10.6859/aja.202112_59(4).0004

BACKGROUND: Preemptive analgesia is important for reducing postoperative analgesia requirement. Therefore, this study compared the efficacy of intravenous (IV) ketamine alone with the efficacy of a combination of low-dose IV ketamine and IV parecoxib as part of a multimodal preemptive analgesia regimen in patients undergoing elective laparotomy.
METHODS: In this prospective study, 48 patients scheduled for elective laparotomy were randomized to two groups of preemptive analgesia, namely, group K-P, in which anestheologists administered a combination of 0.3 mg/kg IV ketamine and 40.0 mg IV parecoxib, or group K, in which ones gave 0.3 mg/kg IV ketamine alone. Patients from both groups underwent surgery under general anesthesia, and total intraoperative opioid requirement was recorded. After surgery, morphine administered by automated patient-controlled analgesia (PCA) infusion device was initiated in all patients. Pain score was assessed using the visual analogue scale (VAS), and postoperative opioid requirement was recorded at 1 and 4 hours, and subsequently from 4-hour intervals up to 24 hours after surgery.
RESULTS: Compared to group K, group K-P required significantly lower rescue IV fentanyl in the recovery bay (0.10 ± 0.28 vs. 0.35 ± 0.46 μg/kg; P = 0.031), showing prolonged time-to-first analgesic request recorded by PCA device (70.8 ± 40.0 vs. 22.2 ± 15.8 mins; P ＜ 0.001), lower total morphine requirement delivered by PCA device (8.0 ± 4.6 vs. 16.8 ± 6.5 mg; P ＜ 0.001), and lower VAS values measured at all time points. There was no significant difference in intraoperative total opioid requirement between the groups.
CONCLUSIONS: Among laparotomy patients, multimodal preemptive analgesia by the use of a combination of low-dose IV ketamine and IV parecoxib was more effective than IV ketamine alone in reducing pain scores and postoperative analgesia requirement (e.g., PCA-administered morphine).
Fulltext Medical Experts' Agreement on Risk Assessment Based on All Possible Combinations of the COVID-19 Predictors-A Novel Approach for Public Health Screening and Surveillance

Ibrahim MS, Naing NN, Abd Aziz A, Makhtar M, Mohamed Yusoff H, Esa NK, et al.

Int J Environ Res Public Health, 2022 Dec 10;19(24).
PMID: 36554487 DOI: 10.3390/ijerph192416601

During the initial phase of the coronavirus disease 2019 (COVID-19) pandemic, there was a critical need to create a valid and reliable screening and surveillance for university staff and students. Consequently, 11 medical experts participated in this cross-sectional study to judge three risk categories of either low, medium, or high, for all 1536 possible combinations of 11 key COVID-19 predictors. The independent experts' judgement on each combination was recorded via a novel dashboard-based rating method which presented combinations of these predictors in a dynamic display within Microsoft Excel. The validated instrument also incorporated an innovative algorithm-derived deduction for efficient rating tasks. The results of the study revealed an ordinal-weighted agreement coefficient of 0.81 (0.79 to 0.82, p-value < 0.001) that reached a substantial class of inferential benchmarking. Meanwhile, on average, the novel algorithm eliminated 76.0% of rating tasks by deducing risk categories based on experts' ratings for prior combinations. As a result, this study reported a valid, complete, practical, and efficient method for COVID-19 health screening via a reliable combinatorial-based experts' judgement. The new method to risk assessment may also prove applicable for wider fields of practice whenever a high-stakes decision-making relies on experts' agreement on combinations of important criteria.