Displaying publications 1 - 20 of 45 in total

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  1. Wali HA, Mazlan R
    J Audiol Otol, 2018 Jan;22(1):20-27.
    PMID: 29061035 DOI: 10.7874/jao.2017.00227
    BACKGROUND AND OBJECTIVES: Although ethnicity effect on wideband absorbance (WBA) findings was evident for adults, its effect on neonates has not been established yet. This study aimed to investigate the influence of ethnicity on WBA measured at 0 daPa from neonates with healthy middle ear functions.

    SUBJECTS AND METHODS: Participants were 99 normal, healthy, full-term newborn babies with chronological age between 11 and 128 hours of age (mean=46.73, standard deviation=26.36). A cross-sectional study design was used to measure WBA at 16 one-third octave frequency points from 99 neonates comprising of three ethnic groups: Malays (n=58), Chinese (n=13) and Indians (n=28). A total of 165 ears (83.3%) that passed a battery of tests involving distortion product otoacoustic emissions, 1 kHz tympanometry and acoustic stapedial reflex were further tested using WBA. Moreover, body size measurements were recorded from each participant.

    RESULTS: The Malays and Indians neonates showed almost identical WBA response across the frequency range while the Chinese babies showed lower absorbance values between 1.25 kHz and 5 kHz. However, the differences observed in WBA between the three ethnic groups were not statistically significant (p=0.23). Additionally, there were no statistically significant difference in birth weight, height and head circumference among the three ethnic groups.

    CONCLUSIONS: This study showed that Malays, Chinese and Indians neonates were not significantly different in their WBA responses. In conclusion, to apply for the ethnic-specific norms is not warranted when testing neonates from population constitute of these three ethnicities.

  2. Kamrani, M.A., Sharifah Zainiyah, S.Y., Hamzah, A., Ahmad, Z.
    MyJurnal
    Adolescents are known to obtain information regarding sexual and reproductive health from a variety of sources and not just during formal lessons in schools. This cross-sectional descriptive study was carried out to determine the source of information on sexual and reproductive health among Form four secondary schools girls in the Klang Valley as well as parents’ relationship profile. A total of 520 secondary school girls were recruited for the study. In this study, the source of information on puberty and sexual topics were categorized as follows: first level of importance - mothers, second level of importance - siblings, third level of importance - fathers, fourth level of importance - friends, fifth level of importance - teachers and sixth level of importance - books/internet. A majority of respondents agreed that their mothers were the first level of importance they sought for information on puberty (74.8%) and sexual topics (53.8%). Thirty nine point three percent (39.3%) of respondents reported it was very easy to have a dialogue with their mothers while only 10.0% of the respondents said it was very easy to have a dialogue with their fathers. While this was the case, only 6.3% of the respondents reported discussing sex-related matter with their mothers.
  3. Nathan S, Aziz DH, Mahadi NM
    Curr Microbiol, 2006 Nov;53(5):412-5.
    PMID: 17036210
    We constructed recombinant phage particles displaying the Bacillus thuringiensis Cry1Ba4 active toxin using the pfUSE5 and pComb3X phagemid vectors. The recombinant phage particles were screened and evaluated for displayed biologically active Cry1Ba4 toxin against the target insect larvae. Concurrent expression of Cry1Ba4 protoxin was carried out using the pETBlue -2 plasmid expression vector in Escherichia coli Tuner (DE3)pLacI and the protoxin was successfully expressed at a size of 129 kDa. In the bioassay, 3.30 mg crude extract of Cry1Ba4 protoxin, 9.35 x 10(9) TU and 7.70 x 10(9) TU of induced recombinant phage particles carrying Cry1Ba4 active toxin displayed on pComb3X and pFUSE5, respectively, demonstrated mortality of greater than 85% against Plutella xylostella (third-instar) within 48 hours. Thus, we have successfully displayed the Cry1Ba4 activated toxin on the surface of a phage and demonstrated toxicity towards larvae.
  4. Wali HA, Mazlan R, Kei J
    Ear Hear, 2019 2 27;40(5):1233-1241.
    PMID: 30807541 DOI: 10.1097/AUD.0000000000000707
    OBJECTIVES: Wideband absorbance (WBA) is an emerging technology to evaluate the conductive pathway (outer and middle ear) in young infants. While a wealth of research has been devoted to measuring WBA at ambient pressure, few studies have investigated the use of pressurized WBA with this population. The purpose of this study was to investigate the effect of age on WBA measured under pressurized conditions in healthy infants from 0 to 6 months of age.

    DESIGN: Forty-four full-term healthy neonates (17 males and 27 females) participated in a longitudinal study. The neonates were assessed at 1-month intervals from 0 to 6 months of age using high-frequency tympanometry, acoustic stapedial reflex, distortion product otoacoustic emissions, and pressurized WBA. The values of WBA at tympanometric peak pressure (TPP) and 0 daPa across the frequencies from 0.25 to 8 kHz were analyzed as a function of age.

    RESULTS: A linear mixed model analysis, applied to the data, revealed significantly different WBA patterns among the age groups. In general, WBA measured at TPP and 0 daPa decreased at low frequencies (<0.4 kHz) and increased at high frequencies (2 to 5and 8 kHz) with age. Specifically, WBA measured at TPP and 0 daPa in 3- to 6-month-olds was significantly different from that of 0- to 2-month-olds at low (0.25 to 0.31 kHz) and high (2 to 5 and 8 kHz) frequencies. However, there were no significant differences between WBA measured at TPP and 0 daPa for infants from 3 to 6 months of age.

    CONCLUSIONS: The present study provided clear evidence of maturation of the outer and middle ear system in healthy infants from birth to 6 months. Therefore, age-specific normative data of pressurized WBA are warranted.

  5. Wali HA, Mazlan R, Kei J
    J Speech Lang Hear Res, 2017 10 17;60(10):2965-2973.
    PMID: 28975265 DOI: 10.1044/2017_JSLHR-H-17-0120
    Purpose: The present study aimed to establish normative data for wideband absorbance (WBA) measured at tympanometric peak pressure (TPP) and 0 daPa and to assess the test-retest reliability of both measurements in healthy neonates.

    Method: Participants of this cross-sectional study included 99 full-term neonates (165 ears) with mean chronological age of 46.7 hrs (SD = 26.3 hrs). Of the 99 neonates, 58 were Malay, 28 were Indian, and 13 were Chinese. The neonates who passed high-frequency (1 kHz) tympanometry, acoustic stapedial reflex, and distortion product otoacoustic emission screening tests were assessed using a pressurized WBA test (wideband tympanometry). To reduce the number of measurement points, the WBA responses were averaged to 16 one-third octave frequency bands from 0.25 to 8 kHz. A mixed-model analysis of variance was applied to the data to investigate the effects of frequency, ear, gender, and ethnicity on WBA. The analysis of variance was also used to compare between WBA measured at TPP and 0 daPa. An interclass correlation coefficient test was applied at each of the 16 frequency bands to measure the test-retest reliability of WBA at TPP and 0 daPa.

    Results: Both WBA measurements at TPP and 0 daPa exhibited a multipeaked pattern with 2 maxima at 1.25-1.6 kHz and 6.3 kHz and 2 minima at 0.5 and 4 kHz. The mean WBA measured at TPP was significantly higher than that measured at 0 daPa at 0.25, 0.4, 0.5, 1.25, and 1.6 kHz only. A normative data set was developed for absorbance at TPP and at 0 daPa. There was no significant effect of ethnicity, gender, and ear on both measurements of WBA. The test-retest reliability of WBA at TPP and 0 daPa was high with the interclass correlation coefficient ranging from 0.77 to 0.97 across the frequencies.

    Conclusions: Normative data of WBA measured at TPP and 0 daPa for neonates were provided in the present study. Although WBA at TPP was slightly higher than the WBA measured at 0 daPa at some frequencies below 2 kHz, the WBA patterns of the 2 measurements were nearly identical. Moreover, the test-retest reliability of both WBA measurements was high.

  6. Hamzah A, Abdulrashid N
    J. Biochem. Mol. Biol. Biophys., 2002 Oct;6(5):365-9.
    PMID: 12385974
    The xylanase gene from Bacillus pumilus PJ19 amplified by polymerase chain reaction (PCR) was cloned into pCRII vector and transformed into Escherichia coli strain INValphaF'. Starting from an ATG as an initiator codon, an open reading frame coding for 202 amino acids was obtained. The recombinant xylanase sequence showed a 96% homology with the xylanase sequence from B. pumilus IPO strain and had an estimated molecular weight of 22,474. Xylanase activity expressed by E. coli INValphaF' harboring the cloned gene was located primarily in the cytoplasmic fraction.
  7. Tavakoli A, Hamzah A
    Iran J Biotechnol, 2017 Mar;15(1):67-73.
    PMID: 28959354 DOI: 10.15171/ijb.1344
    BACKGROUND: Benzaldehyde dehydrogenase (BZDH) is encoded by the xylC that catalyzes the conversion of benzaldehyde into benzoate in many pathways such as toluene degradation.

    OBJECTIVES: In this study, the xylC gene from Rhodococcus ruber UKMP-5M was expressed in Escherichia coli, purified, and characterized.

    MATERIALS AND METHODS: The xylC was amplified and cloned in E. coli. The recombinant plasmid pGEMT-xylC was digested by NdeI and HindIII to construct plasmid pET28b-xylC and transformed in E. coli BL21 (DE3). Expression of the recombinant protein was induced by 1 mM isopropyl β-D-thiogalactoside (IPTG) at 37°C. The BZDH was purified by ion exchange chromatography, in which the product was an NAD-dependent enzyme using benzaldehyde as a substrate for enzyme characterization. The end metabolite was identified via gas chromatography mass spectrometry (GC-MS).

    RESULTS: The recombinant BZDH is 27 kDa, purified by ion exchange chromatography. The activity of BZDH was 9.4 U.μL-1 The optimum pH and temperature were 8.5 and 25ºC, respectively. The Michaelis constant (Km) and maximum velocity (Vmax) were 4.2 mM and 19.7 U.mL-1, respectively. The metabolite of BZDH was benzene carboxylic acid as determined by GC-MS analysis.

    CONCLUSIONS: BZDH has the ability to degrade benzaldehyde to less toxic compounds. The BZDH is a critical enzyme for the degradation of aromatic hydrocarbons in Rhodococcus sp. The BZDH from R. ruber UKMP-5M is showed similar function with other aldehyde dehydrogenases.

  8. Hasani A, Moghavvemi S, Hamzah A
    PLoS One, 2016;11(6):e0157624.
    PMID: 27341569 DOI: 10.1371/journal.pone.0157624
    In many countries, especially one such as Malaysia, tourism has become a key factor in economic development, and the industry heavily relies on feedback from local residents. It is essential to observe and examine the perceptions of residents towards tourists and tourism development for better planning in realizing successful and sustainable tourism development. Therefore, this research measured the relationship between residents' welcoming nature, emotional closeness, and sympathetic understanding (emotional solidarity) towards tourists and their respective attitudes towards supporting tourism development. To test the proposed research model, we collected data using a questionnaire survey from 333 residents in rural areas in Malaysia. We used the structural equation modelling technique (Amos) to evaluate the research model, and the results revealed that the residents' willingness (welcoming nature) to accept tourists is the strongest factor that effects the residents' attitudes towards supporting tourism development. However, there was no significant relationship between residents' emotional closeness and their sympathetic understanding towards tourists with their attitude and support towards tourism development. Welcoming nature, emotional closeness, and sympathetic understanding are able to predict 48% of residents' attitudes towards tourism development and 62% of their support towards tourism development.
  9. Tavakoli A, Hamzah A, Rabu A
    Mol Biol Res Commun, 2016 Sep;5(3):133-142.
    PMID: 28097167
    In this study, benzoate dioxygenase from Rhodococcus ruber UKMP-5M was catalyzed by oxidating the benzene ring to catechol and other derivatives. The benzoate dioxygenase (benA gene) from Rhodococcus ruber UKMP-5M was then expressed, purified, characterized, The benA gene was amplified (642 bp), and the product was cloned into a pGEM-T vector. The recombinant plasmid pGEMT-benA was digested by double restriction enzymes BamHI and HindIII to construct plasmid pET28b-benA and was then ligated into Escherichia coli BL21 (DE3). The recombinant E. coli was induced with 0.5 mM isopropyl β-D-thiogalactoside (IPTG) at 22˚C to produce benzoate dioxygenase. The enzyme was then purified by ion exchange chromatography after 8 purification folds. The resulting product was 25 kDa, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. Benzoate dioxygenase activity was found to be 6.54 U/mL and the optimal pH and temperature were 8.5 and 25°C, respectively. Maximum velocity (Vmax) and Michaelis constant (Km) were 7.36 U/mL and 5.58 µM, respectively. The end metabolite from the benzoate dioxygenase reaction was cyclohexane dione, which was determined by gas chromatography mass spectrometry (GC-MS).
  10. Razali SM, Hamzah AM
    Am J Psychiatry, 1999 Jan;156(1):158.
    PMID: 9892319
  11. Mohammat MF, Shaameri Z, Hamzah AS
    Molecules, 2009;14(1):250-6.
    PMID: 19136912 DOI: 10.3390/molecules14010250
    Some novel 2,3-dioxo-5-(substituted)-arylpyrroles have been synthesized. Among these, pyrrolidine compound 1b was converted to 2,3-dioxo-5-aryl pyrrolidine 2b. Finally a set of hydrazone derivatives was obtained from the reaction of 2b with various hydrazine salts. The structures of all the new synthesized compounds were confirmed by elemental analyses, IR and 1H-NMR spectra.
  12. Hamzah AR, Jalaluddin MA, Raman R
    Ann Otol Rhinol Laryngol, 1999 Mar;108(3):253-4.
    PMID: 10086617
    A patient with Turner's syndrome presented with a rare anomaly of absent oval window, inferiorly placed facial nerve, and abnormal stapes. To our knowledge, this is the first report of this combination of malformations.
  13. Sarmani SB, Abugassa I, Hamzah A, Yahya MD
    Biol Trace Elem Res, 1999;71-72:365-76.
    PMID: 10676512
    Medicinal herb preparations prescribed for specific treatment purposes were purchased from markets and were analyzed by instrumental neutron activation analysis with k0 standardization. Then, 500-700 mg of each sample was pelletized under a pressure of six tones and irradiated together with monitors for alpha and neutron flux ratio determinations for about 6 h in a thermal flux of 2.29 x 10(12) n/cm2/s. The accuracy of the method was established by analyzing standard reference materials. Twenty-nine elements, Ag, As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mn, Mo, Na, Rb, Sb, Sc, Se, Sm, Sr, Th, U, Yb, and Zn, were measured in all the samples, and Hg was detected in some samples, with good accuracy and reproducibility. The concentration of elements determined was found to vary depending on the composition of the herbs used. Although the trend linking the element of the medicinal plants to its curative abilities could not be clearly determined, this study showed that the toxic elements found in the samples were below the levels prescribed by health regulations. Nevertheless, such data are important to understand the pharmacological action and the exact mechanisms of action and formation of active constituents for each medicinal plant and to decide the dosage of the herbs used in the final formulation.
  14. Nguyen NH, Hamzah A, Thoa NP
    Front Genet, 2017;8:82.
    PMID: 28659970 DOI: 10.3389/fgene.2017.00082
    The extent to which genetic gain achieved from selection programs under strictly controlled environments in the nucleus that can be expressed in commercial production systems is not well-documented in aquaculture species. The main aim of this paper was to assess the effects of genotype by environment interaction on genetic response and genetic parameters for four body traits (harvest weight, standard length, body depth, body width) and survival in Red tilapia (Oreochromis spp.). The growth and survival data were recorded on 19,916 individual fish from a pedigreed population undergoing three generations of selection for increased harvest weight in earthen ponds from 2010 to 2012 at the Aquaculture Extension Center, Department of Fisheries, Jitra in Kedah, Malaysia. The pedigree comprised a total of 224 sires and 262 dams, tracing back to the base population in 2009. A multivariate animal model was used to measure genetic response and estimate variance and covariance components. When the homologous body traits in freshwater pond and cage were treated as genetically distinct traits, the genetic correlations between the two environments were high (0.85-0.90) for harvest weight and square root of harvest weight but the estimates were of lower magnitudes for length, width and depth (0.63-0.79). The heritabilities estimated for the five traits studied differed between pond (0.02 to 0.22) and cage (0.07 to 0.68). The common full-sib effects were large, ranging from 0.23 to 0.59 in pond and 0.11 to 0.31 in cage across all traits. The direct and correlated responses for four body traits were generally greater in pond than in cage environments (0.011-1.561 vs. -0.033-0.567 genetic standard deviation units, respectively). Selection for increased harvest body weight resulted in positive genetic changes in survival rate in both pond and cage culture. In conclusion, the reduced selection response and the magnitude of the genetic parameter estimates in the production environment (i.e., cage) relative to those achieved in the nucleus (pond) were a result of the genotype by environment interaction and this effect should be taken into consideration in the future breeding program for Red tilapia.
  15. Thoa NP, Hamzah A, Nguyen NH
    Anim. Reprod. Sci., 2017 Sep;184:94-101.
    PMID: 28709735 DOI: 10.1016/j.anireprosci.2017.07.003
    The present study examines genetic variation and correlated changes in reproductive performance traits in a red tilapia (Oreochromis spp.) population selected over three generations for improved growth. A total of 328 breeding females (offspring of 111 sires and 118 dams) had measurements of body weight prior to spawning (WBS), number of fry at hatching (NFH), total fry weight (TFW) and number of dead fry (NDF) or mortality of fry including unhatched eggs at hatching (MFH). Restricted maximum likelihood (REML) analysis in a multi-trait model showed that there are heritable genetic components for all traits studied. The heritability for WBS was very high (0.80). The estimates for traits related to fecundity (NFH, TFW) and survival (NDF) were low and they were associated with high standard errors. Genetic correlations of WBS with other reproductive performance traits (NFH, TFW and NDF) were generally positive. However, NFH was negatively correlated genetically with TFW. As expected, body measurements during growth stage exhibited strong positive genetic correlations with WBS. The genetic correlations between body traits and reproductive performance (NFH, TFW, NDF) were not significant. Correlated responses in reproductive traits were measured as changes in least squares means between generations or spawning years. Except for WBS that increased with the selection programs, the phenotypic changes in other reproductive traits observed were not statistically significant (P>0.05). It is concluded that the selection program for red tilapia has resulted in very little changes in reproductive performance of the animals after three generations. However, periodic monitoring of genetic changes in fecundity and fitness related traits such as NDF or MFH should be made in selective breeding programs for red tilapia.
  16. Hamzah A, Thoa NP, Nguyen NH
    J Appl Genet, 2017 Nov;58(4):509-519.
    PMID: 28980200 DOI: 10.1007/s13353-017-0411-8
    Quantitative genetic analysis was performed on 10,919 data records collected over three generations from the selection programme for increased body weight at harvest in red tilapia (Oreochromis spp.). They were offspring of 224 sires and 226 dams (50 sires and 60 dams per generation, on average). Linear mixed models were used to analyse body traits (weight, length, width and depth), whereas threshold generalised models assuming probit distribution were employed to examine genetic inheritance of survival rate, sexual maturity and body colour. The estimates of heritability for traits studied (body weight, standard length, body width, body depth, body colour, early sexual maturation and survival) across statistical models were moderate to high (0.13-0.45). Genetic correlations among body traits and survival were high and positive (0.68-0.96). Body length and width exhibited negative genetic correlations with body colour (- 0.47 to - 0.25). Sexual maturity was genetically correlated positively with measurements of body traits (weight and length). Direct and correlated genetic responses to selection were measured as estimated breeding values in each generation and expressed in genetic standard deviation units (σG). The cumulative improvement achieved for harvest body weight was 1.72 σG after three generations or 12.5% per generation when the gain was expressed as a percentage of the base population. Selection for improved body weight also resulted in correlated increase in other body traits (length, width and depth) and survival rate (ranging from 0.25 to 0.81 genetic standard deviation units). Avoidance of black spot parent matings also improved the overall red colour of the selected population. It is concluded that the selective breeding programme for red tilapia has succeeded in achieving significant genetic improvement for a range of commercially important traits in this species, and the large genetic variation in body colour and survival also shows that there are prospects for future improvement of these traits in this population of red tilapia.
  17. Abdul-Wahab J, Naznin M, Suhaimi A, Amir-Hamzah AR
    Singapore Med J, 2007 Jul;48(7):e206-8.
    PMID: 17609817
    Familial myelodysplastic syndrome occurring at a young age is a very rare childhood haematological malignancy. Two siblings, aged three and 18 years, from a consanguineous marriage, presented with pancytopenia and was subsequently diagnosed to have myelodysplastic syndrome. Both remained clinically stable throughout the illness. Splenectomy appeared to have fully corrected the cytopenia in one of them.
  18. Hamzah SR, Suandi T, Krauss SE, Hamzah A, Tamam E
    Int J Adolesc Youth, 2014 Oct 2;19(4):419-433.
    PMID: 25431513
    This study was carried out on the moderating effect of peer attachment on the relationships between religiosity and worldview, and on how hedonistic behaviour among Malaysian undergraduate students is shaped by such influences. With regard to peer attachment, the study focused on the influences of communication, trust and alienation among youth. Bronfenbrenner's theory of human ecology and Armsden and Greenberg's attachment model were used as the framework. Drawing on a quantitative survey of 394 Malaysian university students (M age = 21.0, SD = 0.40), structural equation modelling and path analysis revealed a significant relationship between worldview and hedonistic behaviour. Peer attachment moderated the relationships between religiosity and religious worldview. The results further showed that the unique moderating effect of the lower level of attachment with peers is positively related to the hedonistic behaviour. Implications from the findings are discussed.
  19. Amir Hamzah AR, Tiow CA, Koh GT, Sharifah AM
    Med J Malaysia, 2011 Mar;66(1):19-21.
    PMID: 23765137
    Transcatheter closure of small and moderate sizes of Patent Ductus Arteriosus (PDA) is a standard and well accepted form of treatment. The aim of this study is to describe the experience of transcatheter closure of PDA in Penang Hospital. All patients who underwent transcatheter closure of PDA at our institution between 20th January 2006 and 27th June 2008 were retrospectively identified and studied. There were a total of 66 patients who had undergone transcatheter closure of PDA during this period which comprised of 24 male and 42 female. The PDA was closed by Amplatzer Duct Occluder (ADO) in 31 patients, Gianturco coil in 29 patients and other types of devices in 6 patients. There were 4 patients (6%) who had developed acute complication during the procedure (3 of them developed coil embolization and 1 had bleeding from puncture site). The PDA was successfully close in 95.5% of the study population without any residual PDA shunting. All the patients were alive but 5 of them (4.5%) have some abnormalities (2 has mild left pulmonary stenosis, 3 has small residual). Comparison between ADO and Gianturco coil revealed no significant difference in the outcome. Transcatheter closure of PDA has proven to be safe and effective with good midterm outcome. There was no significant difference between Amplatzer Ductal Occluder and Gianturco coil in term of the outcome.
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