MyMedR

Displaying all 5 publications

Abstract:

Sort:

Fulltext The Acquisition, Analyses and Interpretation of fMRI Data: A Study on Functional Specialisation in Primary Auditory Cortices

Yusuf, A.N., Abdul Hamid, K., Mohamad, M., Abd hamid, A.I.

Medicine & Health, 2008;3(2):300-317.
MyJurnal

In this study, functional magnetic resonance imaging (fMRI) is used to investigate func-tional specialisation in human auditory cortices during listening. A silent fMRI paradigm was used to reduce the scanner sound artefacts on functional images. The subject was instructed to pay attention to the white noise stimulus binaurally given at an inten-sity level of 70 dB higher than the hearing level for normal people. Functional speciali-sation was studied using the Matlab-based Statistical Parametric Mapping (SPM5) software by means of fixed effects (FFX), random effects (RFX) and conjunction analyses. Individual analyses on all subjects indicated asymmetrical bilateral activation of the left and right hemispheres in Brodmann areas (BA) 22, 41 and 42, involving the primary and secondary auditory cortices. The percentage of signal change is larger in the BA22, 41 and 42 on the right as compared to the ones on the left (p>0.05). The average number of activated voxels in all the respective Brodmann areas are higher in the right hemisphere than in the left (p>0.05). FFX results showed that the point of maximum intensity was in the right BA41 whereby 599±1 activated voxels were ob-served in the right temporal lobe as compared to 485±1 in the left temporal lobe. The RFX results were consistent with that of FFX. The analysis of conjunction which fol-lowed, showed that the right BA41 and left BA22 as the common activated areas in all subjects. The results confirmed the specialisation of the right auditory cortices in pro-cessing non verbal stimuli.
Fulltext Effective Connectivity of a Default Mode Network In Human Brain: In Search of a Dominant Node Using Spectral Dynamic Causal Modeling

Mohd Nawi, N. S. A., Rahmad, A. A., Abdul Hamid, K., Rahman, S., Osman, S. S., Surat, S., et al.

Physics and Technology in Medicine, 2020;1(1):1-14.
MyJurnal

The connectivity patterns among the DMN nodes when the brain is resting are still in great debate. Among the unknowns is whether a dominant node exists in the network and if any, how does it influences the other nodes. Resting state functional magnetic resonance imaging (rsfMRI) was utilized in data acquisition on 25 healthy male and female participants. The DMN nodes selected were posterior cingulate cortex (PCC), bilateral inferior parietal cortex (IPL) and medial prefrontal cortex (mPFC). Fully connected causal models were constructed comprising four DMN nodes. The time invariant covariance of the random fluctuations between nodes was then estimated to obtain the effective connectivity (EC) between the DMN nodes. The EC values among the DMN nodes were averaged over the participants using Bayesian Parameter Averaging (BPA). All the DMN nodes have self-inhibitory dynamics. All connections between nodes were significant (P > 0.9) with a condition for any of the two nodes, one node inhibited the others. The PCC which exhibited the highest signal intensity was in fact inhibited by others. Inter-hemispheric RIPC to LIPC connections acted the same way, with excitatory LIPC to RIPC and inhibitory RIPC to LIPC connections. The results also showed a stronger mPFC to RIPC connection in the right hemisphere (as compared to mPFC to LIPC connection in the left hemisphere) and a weaker PCC to RIPC connection in the right hemisphere (as compared to PCC to LIPC connection in the left hemisphere). PCC can be regarded as a dominant node among the four nodes, being connected to all other nodes in different ways. All the four nodes were significantly activated and connected to each other even though the brain was in a state of resting.
Fulltext Development and characterisation of ibuprofen-loaded nanoemulsion with enhanced oral bioavailability

Anuar N, Sabri AH, Bustami Effendi TJ, Abdul Hamid K

Heliyon, 2020 Jul;6(7):e04570.
PMID: 32775730 DOI: 10.1016/j.heliyon.2020.e04570

Lipophilic compounds constitute a majority of therapeutics in the pipeline of drug discovery. Despite possessing enhanced efficacy and permeability, some of these drugs suffer poor solubility necessitating the need of a suitable drug delivery system. Nanoemulsion is a drug delivery system that provides enhanced solubility for poorly soluble drugs in an attempt to improve the oral bioavailability. The purpose of this study is to develop a nanoemulsion system using ibuprofen as a model drug in order to investigate the potential of this colloidal system to enhance the absorption of poorly water-soluble drugs. Ibuprofen loaded-nanoemulsion with different drug concentrations (1.5, 3 and 6% w/w) were formulated from olive oil, sucrose ester L-1695 and glycerol using D-phase emulsification technique. A pseudoternary phase diagram was utilised to identify the optimal excipient composition to formulate the nanoemulsion system. In vitro diffusion chamber studies using rodent intestinal linings highlighted improved absorption profile when ibuprofen was delivered as nanoemulsion in comparison to microemulsions and drug-in-oil systems. This was further corroborated by in vivo studies using rat model that highlighted a two-fold increase in ibuprofen absorption when the drug was administered as a nanoemulsion relative to drug-in-oil system. On the other hand, when ibuprofen was administered as microemulsions, only a 1.5-fold increase in absorption was observed relative to drug-in-oil system. Thus, this study highlights the potential of using nanoemulsion as a drug delivery system to enhance the oral bioavailability of hydrophobic drugs.
Circumventing the Gastrointestinal Barrier for Oral Delivery of Therapeutic Proteins and Peptides (PPTS): Current Trends and Future Trajectories

Hashim LE, Sabri AH, Mohamad MA, Anjani QK, Mustaffa MF, Abdul Hamid K

Curr Drug Deliv, 2024;21(2):211-235.
PMID: 37076462 DOI: 10.2174/1567201820666230418091506

Therapeutic proteins and peptides (PPTs) have become one of the most important biological molecules for the management of many common and complex diseases due to their high specificity and high bioactivity. However, these biomolecules are mainly given by the hypodermic injection, which often leads to poor patient compliance due to the invasive nature of this route of administration. The oral route has been considered the most convenient and patient-friendly route for drug delivery relative to hypodermic injections. Despite the ease and simplicity conferred by oral administration, this drug delivery route suffers rapid peptide degradation in gastric fluid and low intestinal uptake. In order to circumvent these issues, several strategies, such as enzyme inhibitors, permeation enhancers, chemical modification, mucoadhesive and stimuli-responsive polymers, and specialised particulate formulation have been developed. Such strategies are designed with the aim of protecting PPTs from the harsh gastrointestinal environment as well as providing a strategy to enhance the uptake of the therapeutic across the gastrointestinal tract. This review aims to provide an overview of the current development in enteral drug delivery strategies for PPTs. The design of these drug delivery systems in overcoming physical and chemical barriers along the gastrointestinal tract while improving oral bioavailability will be highlighted and discussed.
Fulltext A Pilot Study of the Striatal Dopamine Transporter Levels in Kratom-Dependent and Normal Subjects Using 99mTc-TRODAT-1 Single Photon Emission Computed Tomography-Computed Tomography (SPECT-CT)

Zainudin NAB, Zulkifli NN, Abdul Hamid K, Hashim H, Mansor S

Cureus, 2023 Aug;15(8):e43251.
PMID: 37692587 DOI: 10.7759/cureus.43251

OBJECTIVE: The study aims to elucidate the effects of kratom addiction on dopamine transporter (DAT) using [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N20,S2,S20]oxo-[1R-(exo-exo)]-[99mTc] technetium (99mTc-TRODAT-1) brain single photon emission computed tomography-computed tomography (SPECT-CT) in kratom-dependent and healthy subjects.
MATERIALS AND METHODS: We recruited 12 kratom-dependent subjects and 13 healthy men to participate in this study. Addiction, craving, depression, and cognitive scores were assessed. All subjects received a single bolus injection of 99mTc-TRODAT-1 with 914.1 MBq ± 65.5 of activity (mean ± SD). The brain SPECT-CT images were reconstructed using 3D ordered subset expectation maximization (3D-OSEM) along with attenuation correction (AC), scatter correction (SC), and resolution recovery (RR) with an iteration number of four and a subset of 10. The Cohen's Kappa interrater-reliability between two raters, the standardized uptake value of body weight (SUVBW), and the asymmetrical index percentage (AI%) were evaluated.
RESULTS: Kappa statistics showed a fine agreement of abnormal 99mTc-TRODAT-1 uptake in the striatum region for the kratom-dependent group with the κ value of 0.69 (p = 0.0001), and the percentage of agreement for rater 1 and rater 2 was 56% and 64%, respectively. There was a reduction in average SUV in kratom-dependent subjects compared to healthy control subjects in the left caudate and left striatum (0.938 vs. 1.251, p = 0.014, and 1.055 vs. 1.29, p = 0.036, respectively). There was a significant difference in the AI% of the caudate region between the kratom-dependent group and the normal group (33% vs. 14%, p = 0.019).
CONCLUSION: Our findings signify that kratom addiction, may cause a change in DAT level and the results can be confirmed using 99mTc-TRODAT-1 SPECT-CT.