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Characterisation of micro-sized and nano-sized tungsten oxide-epoxy composites for radiation shielding of diagnostic X-rays

Azman NZ, Siddiqui SA, Low IM

Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4952-7.
PMID: 24094209 DOI: 10.1016/j.msec.2013.08.023

Characteristics of X-ray transmissions were investigated for epoxy composites filled with 2-10 vol% WO3 loadings using synchrotron X-ray absorption spectroscopy (XAS) at 10-40 keV. The results obtained were used to determine the equivalent X-ray energies for the operating X-ray tube voltages of mammography and radiology machines. The results confirmed the superior attenuation ability of nano-sized WO3-epoxy composites in the energy range of 10-25 keV when compared to their micro-sized counterparts. However, at higher synchrotron radiation energies (i.e., 30-40 keV), the X-ray transmission characteristics were similar with no apparent size effect for both nano-sized and micro-sized WO3-epoxy composites. The equivalent X-ray energies for the operating X-ray tube voltages of the mammography unit (25-49 kV) were in the range of 15-25 keV. Similarly, for a radiology unit operating at 40-60 kV, the equivalent energy range was 25-40 keV, and for operating voltages greater than 60 kV (i.e., 70-100 kV), the equivalent energy was in excess of 40 keV. The mechanical properties of epoxy composites increased initially with an increase in the filler loading but a further increase in the WO3 loading resulted in deterioration of flexural strength, modulus and hardness.
Dietary assessment of pre-diabetic patients by using food frequency questionnaire. A systematic review of study quality, study outcome, study questionnaire and their relative validity and reliability

Siddiqui S, Zainal H, Harun SN, Sheikh Ghadzi SM

Clin Nutr ESPEN, 2019 02;29:213-223.
PMID: 30661689 DOI: 10.1016/j.clnesp.2018.10.002

BACKGROUND: The contribution of dietary factors in the development and progression of pre-diabetes has been increasingly recognized. However, due to high variability in dietary habits measurement of dietary intake remains one of the most challenging tasks in this population. Food frequency questionnaire (FFQ) which investigates usual dietary intake can be used to identify frequent consumption of foods such as dietary fat, fiber, grains that are linked to the risk of pre-diabetes.
METHOD: This systematic review was conducted to identify and describe FFQs that measure dietary intake of pre-diabetic patients and to examine their relative validity and reliability. The systematic search was done through electronic databases such as PubMed, CINAHL, PsycINFO, ProQuest and Scopus. Methodological quality of included studies and results of study outcome was also summarized in this review.
RESULT: The search identified 445 papers, of which 18 studies reported 15 FFQs, met inclusion criteria. Most of the FFQs (n = 12) were semi-quantitative while three were frequency measures with portion size estimation of selected food items. Test-retest reliability of FFQ was reported in 7 (38.3%) studies with the correlation coefficient of 0.33-0.92. Relative validity of FFQ was reported in 16 (88.8%) studies with the range of correlation coefficient of 0.08-0.83. Dietary patterns rich in carbohydrate, fat, animal protein and n-3 fatty acids were associated with increased risk of pre-diabetes.
CONCLUSION: No well-established disease-specific FFQ identified in the literature. Development of a valid, practical and reliable tool is needed for better understanding of the impact of diet in pre-diabetic population.
Diet quality and its association with glycemic parameters in different diabetes progression stages. A cross-sectional questionnaire study at a primary care clinic

Siddiqui S, Zainal H, Harun SN, Ghadzi SMS

Clin Nutr ESPEN, 2020 10;39:165-172.
PMID: 32859312 DOI: 10.1016/j.clnesp.2020.06.022

BACKGROUND: Diabetes mellitus is a leading cause of preventable deaths and becomes a major public health concern in Malaysia. Multiple studies have reported the association between diet quality and glycemic parameters among known diabetic subjects. Its influence in individuals with borderline diabetes (i.e. pre-diabetes) or unknown diabetes is still unclear.
OBJECTIVE: The objective of this study was to assess the association between diet quality evaluated by healthy eating index (HEI) with the glucose outcome in individuals with distinct diabetes progression stages, as well as to identify causal factors in relation to their diabetes status.
METHOD: A cross-sectional study was conducted at clinical care setting in Universiti Sains Malaysia (USM) between October 2018-March 2019. Normoglycemic controls (n = 47), at-risk of pre-diabetes (n = 58), pre-diabetes (n = 24) as well as individuals with undiagnosed diabetes (n = 18) were queried about their habitual diet by using Food Frequency Questionnaire (FFQ). Correlation analyses were performed to examine the relationship between HEI score and 1) Fasting plasma glucose (FPG) 2) postprandial blood glucose (2-HPP) and glycosylated hemoglobin (HbA1c). Multinomial regression was performed to identify predictors associated with diabetes status of study participants.
RESULT: Overall, diet quality of study participants was unsatisfactory with the mean score of 58.05 ± 9.07 that need improvement. Total HEI score was negatively correlated with the 2-HPP levels in pre-diabetic patients (r = - 0.45, p = 0.05). No significant association was revealed between glycemic parameters and total HEI score among other groups. Age, body mass index (BMI), triglycerides and female gender were positively correlated with the risk of pre-diabetes, at-risk of pre-diabetes and undiagnosed diabetes (p
Synthesis of novel benzohydrazone-oxadiazole hybrids as β-glucuronidase inhibitors and molecular modeling studies

Taha M, Ismail NH, Imran S, Selvaraj M, Rahim A, Ali M, et al.

Bioorg Med Chem, 2015 Dec 1;23(23):7394-404.
PMID: 26526743 DOI: 10.1016/j.bmc.2015.10.037

A series of compounds consisting of 25 novel oxadiazole-benzohydrazone hybrids (6-30) were synthesized through a five-step reaction sequence and evaluated for their β-glucuronidase inhibitory potential. The IC50 values of compounds 6-30 were found to be in the range of 7.14-44.16μM. Compounds 6, 7, 8, 9, 11, 13, 18, and 25 were found to be more potent than d-saccharic acid 1,4-lactone (48.4±1.25μM). These compounds were further subjected for molecular docking studies to confirm the binding mode towards human β-d-glucuronidase active site. Docking study for compound 13 (IC50=7.14±0.30μM) revealed that it adopts a binding mode that fits within the entire pocket of the binding site of β-d-glucuronidase. Compound 13 has the maximum number of hydrogens bonded to the residues of the active site as compared to the other compounds, that is, the ortho-hydroxyl group forms hydrogen bond with carboxyl side chain of Asp207 (2.1Å) and with hydroxyl group of Tyr508 (2.6Å). The other hydroxyl group forms hydrogen bond with His385 side chain (2.8Å), side chain carboxyl oxygen of Glu540 (2.2Å) and Asn450 side-chain's carboxamide NH (2.1Å).
Gender differences in the modifiable risk factors associated with the presence of prediabetes: A systematic review

Siddiqui S, Zainal H, Harun SN, Sheikh Ghadzi SM, Ghafoor S

Diabetes Metab Syndr, 2020 07 08;14(5):1243-1252.
PMID: 32688241 DOI: 10.1016/j.dsx.2020.06.069

BACKGROUND: Prediabetes is a risk state for the future development of type 2 diabetes. Previously, it was evident that the risk factors for diabetes differ by gender. However, conclusive evidence regarding the gender difference in modifiable risk factors associated with the presence of pre-diabetes is still lacking.
AIMS: To systematically identify and summarize the available literature on whether the modifiable risk factors associated with prediabetes displays similar relationship in both the genders.
METHODS: A systematic search was performed on electronic databases i.e. PubMed, EBSCOhost, and Scopus using "sex", "gender", "modifiable risk factors" and "prediabetes" as keywords. Reference list from identified studies was used to augment the search strategy. Methodological quality and results from individual studies were summarized in tables.
RESULTS: Gender differences in the risk factor association were observed among reviewed studies. Overall, reported association between risk factors and prediabetes apparently stronger among men. In particular, abdominal obesity, dyslipidemia, smoking and alcohol drinking habits were risk factors that showed prominent association among men. Hypertension and poor diet quality may appear to be stronger among women. General obesity showed stringent hold, while physical activity not significantly associated with the risk of prediabetes in both the genders.
CONCLUSIONS: Evidence suggests the existence of gender differences in risk factors associated with prediabetes, demands future researchers to analyze data separately based on gender. The consideration and the implementation of gender differences in health policies and in diabetes prevention programs may improve the quality of care and reduce number of diabetes prevalence among prediabetic subjects.
Synthesis of 2-methoxybenzoylhydrazone and evaluation of their antileishmanial activity

Taha M, Baharudin MS, Ismail NH, Khan KM, Jaafar FM, Samreen, et al.

Bioorg Med Chem Lett, 2013 Jun 1;23(11):3463-6.
PMID: 23608761 DOI: 10.1016/j.bmcl.2013.03.051

Compounds 1-25 showed varying degree of antileishmanial activities with IC50 values ranging between 1.95 and 88.56 μM. Compounds 2, 10, and 11 (IC50=3.29±0.07 μM, 1.95±0.04 μM, and 2.49±0.03 μM, respectively) were found to be more active than standard pentamidine (IC50=5.09±0.04 μM). Compounds 7 (IC50=7.64±0.1 μM), 8 (IC50=13.17±0.46 μM), 18 (IC50=13.15±0.02 μM), and 24 (IC50=15.65±0.41 μM) exhibited good activities. Compounds 1, 3, 4, 5, 9, 12, 15, 18, and 19 were found to be moderately active. Compounds 13, 14, 16, 17, 20-25 showed weak activities with IC50 values ranging between 57 and 88 μM.
Analysis of dental erosion induced by different beverages and validity of equipment for identifying early dental erosion, in vitro study

Jameel RA, Khan SS, Abdul Rahim ZH, Bakri MM, Siddiqui S

J Pak Med Assoc, 2016 Jul;66(7):843-8.
PMID: 27427133

To understand early dental erosion induced by different beverages and the equipment for its detection.
Synthesis of novel N-(1,3-thiazol-2-yl)benzamide clubbed oxadiazole scaffolds: Urease inhibition, Lipinski rule and molecular docking analyses

Athar Abbasi M, Raza H, Aziz-Ur-Rehman, Zahra Siddiqui S, Adnan Ali Shah S, Hassan M, et al.

Bioorg Chem, 2019 03;83:63-75.
PMID: 30342387 DOI: 10.1016/j.bioorg.2018.10.018

Present work aimed to synthesize some unique bi-heterocyclic benzamides as lead compounds for the in vitro inhibition of urease enzyme, followed by in silico studies. These targeted benzamides were synthesized in good yields through a multi-step protocol and their structures were confirmed by IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. The in vitro screening results showed that most of the ligands exhibited good inhibitory potentials against the urease. Chemo-informatics analysis envisaged that all these compounds obeyed the Lipinski's rule. Molecular docking results showed that 7h exhibited good binding energy value (-8.40 kcal/mol) and was bound within the active region of urease enzyme. From the present investigation, it was inferred that some of these potent urease inhibitors might serve as novel templates in drug designing.
How confident are pharmacists in providing pharmaceutical care on anticoagulants? A cross-sectional, self-administered questionnaire study in Borneo, Malaysia

Tan SL, Yong ZY, Liew JES, Zainal H, Siddiqui S

J Pharm Policy Pract, 2021 Nov 09;14(1):97.
PMID: 34753518 DOI: 10.1186/s40545-021-00377-w

BACKGROUND: Anticoagulants are the cornerstone therapy for the management of venous thromboembolism (VTE) and atrial fibrillation (AF). Pharmacists should be confident and equipped with the skill and updated knowledge in managing anticoagulation therapy.
OBJECTIVE: To explore self-reported confidence level of pharmacists, perceived reasons influencing their confidence and socio-demographic associated with high confidence level in the area of anticoagulation.
METHODS: A cross-sectional, self-administered questionnaire survey was carried out among fully registered pharmacists who work in selected government hospitals and clinics in Borneo, Malaysia, from January 2019 to February 2020.
RESULTS: Overall, responses from 542 fully registered pharmacists were obtained. Proportion of respondents who claimed confident in providing necessary information to patient receiving warfarin (n = 479, 88.3%) was significantly higher (p
Patterns of dyslipidemia and its associated factors among prediabetic subjects. A cross-sectional study at a primary care clinic

Siddiqui S, Harun SN, Ghadzi SMS, Wahid NA, Hassan AB, Zainal H

Malays Fam Physician, 2023;18:73.
PMID: 38213389 DOI: 10.51866/oa.125

INTRODUCTION: Diabetes is closely linked to cardiovascular diseases, with diabetic dyslipidaemia serving as an established marker of the acceleration of complications, contributing to an increased cardiovascular risk among patients. Timely detection and early characterization of lipid abnormalities can help clinicians in implementing effective preventive measures. This study aimed to determine the patterns and associated factors of dyslipidaemia among Malaysian subjects with borderline diabetes.
METHODS: A retrospective study was conducted among subjects with borderline diabetes aged ≥18 years who visited a primary healthcare centre at Universiti Sains Malaysia from January 2017 to December 2018. Sociodemographic, clinical and laboratory data were obtained from electronic medical records. Data were analysed using SPSS version 25.
RESULTS: A total of 250 participants with borderline diabetes were included in the analysis. Of them, 93.6% (n=234) had lipid abnormalities. Isolated dyslipidaemia characterised by a high low-density lipoprotein cholesterol (LDL-C) level (38.8%, n=97) was the most common pattern found, followed by combined dyslipidaemia of high LDL-C and triglyceride (TG) levels (22.8%, n=57). The male sex was found to be significantly associated with hypertriglyceridemia (adjusted odds ratio [AOR] = 1.86, 95% confidence interval [CI] =1.09-3.1)(P=0.02). Diastolic blood pressure ≥90mmHg was significantly associated with a low HDL-C level (A0R=2.09, 95% CI=1.0-4.1) (P=0.03).
CONCLUSION: The majority of subjects with borderline diabetes have lipid abnormalities. Specifically, isolated dyslipidaemia characterised by a high LDL-C level is alarmingly prevalent. Further large-scale robust studies are needed to confirm the present findings.
Synthesis of novel inhibitors of α-glucosidase based on the benzothiazole skeleton containing benzohydrazide moiety and their molecular docking studies

Taha M, Ismail NH, Lalani S, Fatmi MQ, Atia-Tul-Wahab, Siddiqui S, et al.

Eur J Med Chem, 2015 Mar 6;92:387-400.
PMID: 25585009 DOI: 10.1016/j.ejmech.2015.01.009

In an effort to design and synthesize a new class of α-glucosidase inhibitor, we synthesized benzothiazole hybrid having benzohydrazide moiety (5). Compound 5 was reacted with various substituted aryl aldehyde to generate a small library of compounds 6-35. Synthesis of compounds was confirmed by the spectral information. These compounds were screened for their α-glucosidase activity. They showed a varying degree of α-glucosidase inhibition with IC50 values ranging between 5.31 and 53.34 μM. Compounds 6, 7, 9-16, 19, 21-30, 32-35 showed superior activity as compared to standard acarbose (IC50 = 906 ± 6.3 μM). This has identified a new class of α-glucosidase inhibitors. The predicted physico-chemical properties indicated the drug appropriateness for most of these compounds, as they obey Lipinski's rule of five (RO5). A hybrid B3LYP density functional theory (DFT) was employed for energy, minimization of 3D structures for all synthetic compounds using 6-311 + G(d,p) basis sets followed by molecular docking to explore their interactions with human intestinal C- and N-terminal domains of α-glucosidase. All compounds bind to the prospective allosteric site of the C- terminal domain, and consequently, may be considered as mixed inhibitors. It was hypothesized that both the dipole moment and H-bond interactions govern the biological activation of these compounds.
2-Aminothiazole-Oxadiazole Bearing N-Arylated Butanamides: Convergent Synthesis, Tyrosinase Inhibition, Kinetics, Structure-Activity Relationship, and Binding Conformations

Raza H, Rehman Sadiq Butt A, Athar Abbasi M, Aziz-Ur-Rehman, Zahra Siddiqui S, Hassan M, et al.

Chem Biodivers, 2023 Feb;20(2):e202201019.
PMID: 36597268 DOI: 10.1002/cbdv.202201019

A multi-step synthesis of novel bi-heterocyclic N-arylated butanamides was consummated through a convergent strategy and the structures of these medicinal scaffolds, 7a-h, were corroborated using spectral techniques. The in vitro analysis of these hybrid molecules revealed their potent tyrosinase inhibition as compared to the standard used. The kinetics mechanism was investigated through Lineweaver-Burk plots which exposed that, 7f, inhibited tyrosinase enzyme non-competitively by forming the enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.025 μM. Their binding conformations were ascertained by in silico computational studies whereby these molecules disclosed good binding energy values (kcal/mol). So, it was anticipated from the current research that these bi-heterocyclic butanamides might be probed as imperative therapeutic agents for melanogenesis.

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