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The major bioactive components of seaweeds and their mosquitocidal potential

Yu KX, Jantan I, Ahmad R, Wong CL

Parasitol Res, 2014 Sep;113(9):3121-41.
PMID: 25115733 DOI: 10.1007/s00436-014-4068-5

Seaweeds are one of the most widely studied natural resources for their biological activities. Novel seaweed compounds with unique chemical structures have been reported for their pharmacological properties. The urge to search for novel insecticidal compound with a new mode of action for development of botanical insecticides supports the relevant scientific research on discovering the bioactive compounds in seaweeds. The mosquitocidal potential of seaweed extracts and their isolated compounds are documented in this review paper, along with the discussion on bioactivities of the major components of seaweeds such as polysaccharides, phenolics, proteins, terpenes, lipids, and halogenated compounds. The effects of seaweed extracts and compounds toward different life stages of mosquito (egg, larva, pupa, and adult), its growth, development, and reproduction are elaborated. The structure-activity relationships of mosquitocidal compounds are discussed to extrapolate the possible chemical characteristics of seaweed compounds responsible for insecticidal properties. Furthermore, the possible target sites and mode of actions of the mosquitocidal seaweed compounds are included in this paper. The potential synergistic effects between seaweeds and commercial insecticides as well as the toxic effects of seaweed extracts and compounds toward other insects and non-target organisms in the same habitat are also described. On top of that, various factors that influence the mosquitocidal potential of seaweeds, such as abiotic and biotic variables, sample preparation, test procedures, and considerations for a precise experimental design are discussed. The potential of active seaweed extracts and compounds in the development of effective bioinsecticide are also discussed.
Reproducibility of facial soft tissue landmarks on facial images captured on a 3D camera

Othman SA, Ahmad R, Mericant AF, Jamaludin M

Aust Orthod J, 2013 May;29(1):58-65.
PMID: 23785939

Fast and non-invasive systems of the three-dimensional (3D) technology are a recent trend in orthodontics. The reproducibility of facial landmarks is important so that 3D facial measurements are accurate and may-be applied clinically. The aim of this study is to evaluate the reproducibility of facial soft tissue landmarks using a non-invasive stereo-photogrammetry 3D camera.
Fulltext Mechanomyogram for muscle function assessment: a review

Islam MA, Sundaraj K, Ahmad RB, Ahamed NU

PLoS One, 2013;8(3):e58902.
PMID: 23536834 DOI: 10.1371/journal.pone.0058902

BACKGROUND: Mechanomyography (MMG) has been extensively applied in clinical and experimental practice to examine muscle characteristics including muscle function (MF), prosthesis and/or switch control, signal processing, physiological exercise, and medical rehabilitation. Despite several existing MMG studies of MF, there has not yet been a review of these. This study aimed to determine the current status on the use of MMG in measuring the conditions of MFs.
METHODOLOGY/PRINCIPAL FINDINGS: Five electronic databases were extensively searched for potentially eligible studies published between 2003 and 2012. Two authors independently assessed selected articles using an MS-Word based form created for this review. Several domains (name of muscle, study type, sensor type, subject's types, muscle contraction, measured parameters, frequency range, hardware and software, signal processing and statistical analysis, results, applications, authors' conclusions and recommendations for future work) were extracted for further analysis. From a total of 2184 citations 119 were selected for full-text evaluation and 36 studies of MFs were identified. The systematic results find sufficient evidence that MMG may be used for assessing muscle fatigue, strength, and balance. This review also provides reason to believe that MMG may be used to examine muscle actions during movements and for monitoring muscle activities under various types of exercise paradigms.
CONCLUSIONS/SIGNIFICANCE: Overall judging from the increasing number of articles in recent years, this review reports sufficient evidence that MMG is increasingly being used in different aspects of MF. Thus, MMG may be applied as a useful tool to examine diverse conditions of muscle activity. However, the existing studies which examined MMG for MFs were confined to a small sample size of healthy population. Therefore, future work is needed to investigate MMG, in examining MFs between a sufficient number of healthy subjects and neuromuscular patients.
Three dimensional quantification of mandibular bone remodeling using standard tessellation language registration based superimposition

Ahmad R, Abu-Hassan MI, Li Q, Swain MV

Clin Oral Implants Res, 2013 Nov;24(11):1273-9.
PMID: 22862429 DOI: 10.1111/j.1600-0501.2012.02566.x

The aim of this study was to evaluate a new method to quantify longitudinal mandibular bone remodeling three-dimensionally by superimposition of cone beam computed tomography images.
Contrecoup injury in patients with traumatic temporal bone fracture

Asha'Ari ZA, Ahmad R, Rahman J, Kamarudin N, Ishlah LW

J Laryngol Otol, 2011 Aug;125(8):781-5.
PMID: 21524330 DOI: 10.1017/S0022215111000545

To study the prevalence and patterns of contrecoup injury in traumatic temporal bone fracture cases.
Patterns of intracranial hemorrhage in petrous temporal bone fracture

Asha'ari ZA, Ahmad R, Rahman J, Yusof RA, Kamarudin N

Auris Nasus Larynx, 2012 Apr;39(2):151-5.
PMID: 21592698 DOI: 10.1016/j.anl.2011.02.010

To study the relationship pattern of intracranial hemorrhage in cases of traumatic petrous temporal bone fracture.
Lactobacillus gasseri [corrected] CHO-220 and inulin reduced plasma total cholesterol and low-density lipoprotein cholesterol via alteration of lipid transporters

Ooi LG, Ahmad R, Yuen KH, Liong MT

J Dairy Sci, 2010 Nov;93(11):5048-58.
PMID: 20965319 DOI: 10.3168/jds.2010-3311

This randomized, double-blind, placebo-controlled, and parallel-designed study was conducted to investigate the effect of a synbiotic product containing Lactobacillus gasseri [corrected] CHO-220 and inulin on lipid profiles of hypercholesterolemic men and women. Thirty-two hypercholesterolemic men and women with initial mean plasma cholesterol levels of 5.7±0.32 mmol/L were recruited for the 12-wk study. The subjects were randomly allocated to 2 groups; namely the treatment group (synbiotic product) and the control group (placebo), and each received 4 capsules of synbiotic or placebo daily. Our results showed that the mean body weight, energy, and nutrient intake of the subjects did not differ between the 2 groups over the study period. The supplementation of synbiotic reduced plasma total cholesterol and low-density lipoprotein (LDL)-cholesterol by 7.84 and 9.27%, respectively, compared with the control over 12 wk. Lipoproteins were subsequently subfractionated and characterized. The synbiotic supplementation resulted in a lower concentration of triglycerides in the very low, intermediate, low, and high-density lipoprotein particles compared with the control over 12 wk. The concentration of triglycerides in lipoproteins is positively correlated with an increased risk of atherosclerosis. Our results showed that the synbiotic might exhibit an atheropreventive characteristic. Cholesteryl ester (CE) in the high-density lipoprotein particles of the synbiotic group was also higher compared with the control, indicating greater transport of cholesterol in the form of CE to the liver for hydrolysis. This may have led to the reduced plasma total cholesterol level of the synbiotic group. The supplementation of synbiotic also reduced the concentration of CE in the LDL particles compared with the control, leading to the formation of smaller and denser particles that are more easily removed from blood. This supported the reduced LDL-cholesterol level of the synbiotic group compared with the control. Our present study showed that the synbiotic product improved plasma total- and LDL-cholesterol levels by modifying the interconnected pathways of lipid transporters. In addition, although Lactobacillus gasseri [corrected] CHO-220 could deconjugate bile, our results showed a statistically insignificant difference in the levels of conjugated, deconjugated, primary, and secondary bile acids between the synbiotic and control groups over 12 wk, indicating safety from bile-related toxicity.
Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes

Teh SS, Ahmad R, Wan-Abdullah WN, Liong MT

J Food Sci, 2010 Apr;75(3):M155-64.
PMID: 20492305 DOI: 10.1111/j.1750-3841.2010.01538.x

Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).
Evaluation of agrowastes as immobilizers for probiotics in soy milk

Teh SS, Ahmad R, Wan-Abdullah WN, Liong MT

J Agric Food Chem, 2009 Nov 11;57(21):10187-98.
PMID: 19821558 DOI: 10.1021/jf902003a

The objective of this study was to evaluate agricultural wastes as immobilizers for probiotics in liquid foods, such as soy milk. Probiotic strains were initially evaluated for acid and bile tolerance and the ability to produce alpha-galactosidase. Rinds of durian, mangosteen, and jackfruit were dried, ground, and sterilized prior to immobilization of selected strains ( Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and Lactobacillus bulgaricus FTCC 0411). Immobilized cells were inoculated into soy milk, and growth properties were evaluated over 168 h at 37 degrees C. Soy milk containing free cells without agrowastes was used as the control. Immobilized probiotics showed increased growth, greater reduction of stachyose, sucrose, and glucose, higher production of lactic and acetic acids, and lower pH in soy milk compared to the control. The results illustrated that agrowastes could be used for the immobilization of probiotics with enhanced growth, utilization of substrates, and production of organic acids.
Predicting safe tonsillectomy for ambulatory surgery

Ahmad R, Abdullah K, Amin Z, Rahman JA

Auris Nasus Larynx, 2010 Apr;37(2):185-9.
PMID: 19720483 DOI: 10.1016/j.anl.2009.06.010

To assess the safety of tonsillectomy procedure in local setting.
Fulltext Posterior mediastinal abscess secondary to esophageal perforation following fish bone ingestion

Ahmad R, Ishlah W, Shaharudin MH, Sathananthar KS, Norie A

Med J Malaysia, 2008 Jun;63(2):162-3.
PMID: 18942310 MyJurnal

Accidental swallowing of fish bone, which arrested in esophagus, is fairly common. However the incidence of esophageal perforation due to fish bone swallowing is low. Delayed posterior mediastinal abscess as a result of the esophageal perforation is a rare manifestation and may lead to fatal outcome. Two cases of delayed formation of posterior mediastinal abscess following esophageal perforation due to accidental fish bone ingestion are described here. In these cases patients presented with interscapular back pain. In one of the cases the patient died because of the presentation was misdiagnosed hence leading to delay in the intervention. Radiological findings and surgical management namely esophagoscopy and neck exploration are briefly described.
Fulltext Surgical management of juvenile nasopharyngeal angiofibroma without angiographic embolization

Ahmad R, Ishlah W, Azilah N, Rahman JA

Asian J Surg, 2008 Oct;31(4):174-8.
PMID: 19010758 DOI: 10.1016/S1015-9584(08)60081-0

Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign neoplasm that occurs almost exclusively in the nasopharynx of adolescent males. Surgery remains the primary treatment of choice. JNA has always presented a management challenge to surgeons because of its vascular nature, site of occurrence, and local tissue destruction. The surgical approaches are either standard open method which include external or intraoral incisions, or the recent advanced approach, i.e. via using the endonasal endoscope. It is widely accepted that the use of preoperative angiographic embolization reduces the occurrence of intraoperative bleeding and facilitates tumour removal. However, angiographic embolization is not available at all centres. The purpose of this article is to present our experience with five patients diagnosed with JNA who were resected without embolization, using various surgical approaches. Two tumours were removed via endonasal endoscopic surgery. None of the tumours were embolized prior to surgery. We highlight the preoperative evaluation of tumour extent, using both computed tomography (CT) and magnetic resonance angiography, and the importance of temporary clamping of the external carotid artery intraoperatively. Our results suggest that the latter procedure is a safe and effective means of facilitating surgery and reducing intraoperative bleeding.
Current status and future trends in Cryptosporidium and Giardia epidemiology in Malaysia

Lim YA, Ahmad RA, Smith HV

J Water Health, 2008 Jun;6(2):239-54.
PMID: 18209286 DOI: 10.2166/wh.2008.023

Cryptosporidium and Giardia are major causes of diarrhoeal diseases of humans worldwide, and are included in the World Health Organisation's 'Neglected Diseases Initiative'. Cryptosporidium and Giardia occur commonly in Malaysian human and non-human populations, but their impact on disease, morbidity and cost of illness is not known. The commonness of contributions from human (STW effluents, indiscriminate defaecation) and non-human (calving, lambing, muck spreading, slurry spraying, pasturing/grazing of domestic animals, infected wild animals) hosts indicate that many Malaysian environments, particularly water and soil, are sufficiently contaminated to act as potential vehicles for the transmission of disease. To gain insight into the morbidity and mortality caused by human cryptosporidiosis and giardiasis, they should be included into differential diagnoses, and routine laboratory testing should be performed and (as for many infectious diseases) reported to a centralised public health agency. To understand transmission routes and the significance of environmental contamination better will require further multidisciplinary approaches and shared resources, including raising national perceptions of the parasitological quality of drinking water. Here, the detection of Cryptosporidium and Giardia should be an integral part of the water quality requirement. A multidisciplinary approach among public health professionals in the water industry and other relevant health- and environment-associated agencies is also required in order to determine the significance of Cryptosporidium and Giardia contamination of Malaysian drinking water. Lastly, adoption of validated methods to determine the species, genotype and subgenotype of Cryptosporidium and Giardia present in Malaysia will assist in developing effective risk assessment, management and communication models.
Fulltext Antioxidant Activity and Phenolic Content of Streblus asper Leaves from Various Drying Methods

Ibrahim NM, Mat I, Lim V, Ahmad R

Antioxidants (Basel), 2013;2(3):156-66.
PMID: 26784343 DOI: 10.3390/antiox2030156

Aqueous and ethanol extracts of oven and freeze-dried Streblus asper leaves were investigated using DPPH assay. The presence of phenolic compounds and flavonoids in the extracts, which were detected by Folin and colorimetric assays, respectively, may be responsible for the antioxidant activities of S. asper. The different drying treatments resulted in significant differences (p < 0.05) in the antioxidant properties as well as the phenolic and flavonoid contents of the S. asper extracts. Freeze-dried S. asper leaf extracts exhibited high DPPH radical scavenging activity ranging from 69.48% ± 0.03% to 89.25% ± 0.01% at concentrations ranging from 0 to 1 mg/mL, significantly higher compared with the oven-dried extracts which were in the range of 68.56% ± 0.01% to 86.68% ± 0.01%. Generally, the 70% ethanol extract of the freeze-dried samples exhibited higher phenolic and flavonoid content than the aqueous extract, with values of 302.85 ± 0.03 mg GAE/g and 22.70 ± 0.02 mg QE/g compared with 226.8 ± 0.03 mg GAE/g and 15.38 ± 0.05 mg QE/g, respectively. This study showed that S. asper leaf extracts contain a number of health promoting bioactive compounds, such as phenolic compounds, and are potential sources of natural antioxidants.
An evaluation of the effects of handpiece speed, abrasive characteristics, and polishing load on the flexural strength of polished ceramics

Ahmad R, Morgano SM, Wu BM, Giordano RA

J Prosthet Dent, 2005 Nov;94(5):421-9.
PMID: 16275301

Many studies on the strengthening effects of grinding and polishing, as well as heat treatment on ceramics, are not well standardized or use commercially available industrial polishing systems. The reported effectiveness of these strengthening mechanisms on ceramics may not be applicable to clinical dentistry.
Fulltext Mosquitocidal and Oviposition Repellent Activities of the Extracts of Seaweed Bryopsis pennata on Aedes aegypti and Aedes albopictus

Yu KX, Wong CL, Ahmad R, Jantan I

Molecules, 2015;20(8):14082-102.
PMID: 26247928 DOI: 10.3390/molecules200814082

The ever-increasing threat from infectious diseases and the development of insecticide resistance in mosquito populations drive the global search for new natural insecticides. The aims of this study were to evaluate the mosquitocidal activity of the extracts of seaweed Bryopsis pennata against dengue vectors Aedes aegypti and Aedes albopictus, and determine the seaweed's toxic effect on brine shrimp nauplii (as a non-target organism). In addition, the chemical compositions of the active larvicidal extract and fraction were analyzed by using liquid chromatography-mass spectrometry (LC-MS). Chloroform extract exhibited strong ovicidal activity (with LC50 values of 229.3 and 250.5 µg/mL) and larvicidal activity against Ae. aegypti and Ae. albopictus. The larvicidal potential of chloroform extract was further ascertained when its A7 fraction exhibited strong toxic effect against Ae. aegypti (LC50 = 4.7 µg/mL) and Ae. albopictus (LC50 = 5.3 µg/mL). LC-MS analysis of the chloroform extract gave a tentative identification of 13 compounds; Bis-(3-oxoundecyl) tetrasulfide was identified as the major compound in A7 fraction. Methanol extract showed strong repellent effect against female oviposition, along with weak adulticidal activity against mosquito and weak toxicity against brine shrimp nauplii. The mosquitocidal results of B. pennata suggest further investigation for the development of effective insecticide.
Fulltext Biomechanics of oral mucosa

Chen J, Ahmad R, Li W, Swain M, Li Q

J R Soc Interface, 2015 Aug 06;12(109):20150325.
PMID: 26224566 DOI: 10.1098/rsif.2015.0325

The prevalence of prosthodontic treatment has been well recognized, and the need is continuously increasing with the ageing population. While the oral mucosa plays a critical role in the treatment outcome, the associated biomechanics is not yet fully understood. Using the literature available, this paper provides a critical review on four aspects of mucosal biomechanics, including static, dynamic, volumetric and interactive responses, which are interpreted by its elasticity, viscosity/permeability, apparent Poisson's ratio and friction coefficient, respectively. Both empirical studies and numerical models are analysed and compared to gain anatomical and physiological insights. Furthermore, the clinical applications of such biomechanical knowledge on the mucosa are explored to address some critical concerns, including stimuli for tissue remodelling (interstitial hydrostatic pressure), pressure-pain thresholds, tissue displaceability and residual bone resorption. Through this review, the state of the art in mucosal biomechanics and their clinical implications are discussed for future research interests, including clinical applications, computational modelling, design optimization and prosthetic fabrication.
Worm burden and leukocyte response in Angiostrongylus malaysiensis-infected rats: the influence of testosterone

Kamis AB, Ahmad RA, Badrul-Munir MZ

Parasitol Res, 1992;78(5):388-91.
PMID: 1495916

Gonadectomized male albino rats aged 7 weeks were given 1.5 mg/kg testosterone propionate daily and inoculated with 50 third-stage larvae of Angiostrongylus malaysiensis. The treatment significantly increased the number of larvae and adult worms recovered from the brain and pulmonary arteries, respectively, and the rats exhibited smaller thymus glands. The total numbers of leukocytes, monocytes, neutrophils, and especially eosinophils increased significantly post-infection, but the counts were higher in the untreated infected controls. Presumably, immunosuppressive effects of testosterone may at least partly be responsible for the higher loads of A. malaysiensis worms found in male rats as compared with females in the field.
The influence of thyroxine and propyl thiouracil on Parastrongylus malaysiensis infection in rats

Kamis AB, Ahmad RA, Chang JS, Ambu S

Parasitol Res, 1994;80(1):87-8.
PMID: 8153134

Daily intramuscular injection with thyroxine (T4) at a dose of 2.5 micrograms/100 g body weight decreased the larvae and adult worm burden of Parastrongylus malaysiensis in the brain and pulmonary arteries of male Sprague-Dawley albino rats. In contrast, rats treated with propyl thiouracil (PTU), an antithyroid drug, at a dose of 3.75 mg/100 g body weight retained greater numbers of larvae and adult worms. The results may reflect the contrasting immunomodulatory effects of T4 and PTU that influence the susceptibility of the host.
Effects of estradiol on worm burden and peripheral leukocytes in Parastrongylus malaysiensis-infected rats

Kamis AB, Ahmad RA, Badrul-Munir MZ

Parasitol Res, 1994;80(1):74-7.
PMID: 8153130

Gonadectomized male laboratory rats were given 0.06 mg/kg estradiol benzoate daily for 14 days before being inoculated with 50 third-stage larvae of Parastrongylus malaysiensis. Hormone treatment was continued until the rats were killed. The numbers of larvae in the brain and of adult worms in the pulmonary area of the rats were determined every 7 days after the inoculation. It was found that the rats treated daily with estradiol benzoate had significantly and consistently higher numbers of larvae and adult worms as compared with the controls. The number of total leukocytes increased significantly after the rats were infected. The results show that estradiol-treated rats become susceptible to P. malaysiensis infection, which may indicate that the immunosuppressive effects of testosterone observed in earlier studies may partly be caused by estradiol that was peripherally aromatized from testosterone.

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