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Computed and conventional chest radiography: a comparison of image quality and radiation dose

Ramli K, Abdullah BJ, Ng KH, Mahmud R, Hussain AF

Australas Radiol, 2005 Dec;49(6):460-6.
PMID: 16351609

The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P > 0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (chi(2) tests).
Fulltext Defects in nerve conduction velocity and different muscle fibre-type specificity contribute to muscle weakness in Ts1Cje Down syndrome mouse model

Bala U, Leong MP, Lim CL, Shahar HK, Othman F, Lai MI, et al.

PLoS One, 2018;13(5):e0197711.
PMID: 29795634 DOI: 10.1371/journal.pone.0197711

BACKGROUND: Down syndrome (DS) is a genetic disorder caused by presence of extra copy of human chromosome 21. It is characterised by several clinical phenotypes. Motor dysfunction due to hypotonia is commonly seen in individuals with DS and its etiology is yet unknown. Ts1Cje, which has a partial trisomy (Mmu16) homologous to Hsa21, is well reported to exhibit various typical neuropathological features seen in individuals with DS. This study investigated the role of skeletal muscles and peripheral nerve defects in contributing to muscle weakness in Ts1Cje mice.
RESULTS: Assessment of the motor performance showed that, the forelimb grip strength was significantly (P<0.0001) greater in the WT mice compared to Ts1Cje mice regardless of gender. The average survival time of the WT mice during the hanging wire test was significantly (P<0.0001) greater compared to the Ts1Cje mice. Also, the WT mice performed significantly (P<0.05) better than the Ts1Cje mice in the latency to maintain a coordinated motor movement against the rotating rod. Adult Ts1Cje mice exhibited significantly (P<0.001) lower nerve conduction velocity compared with their aged matched WT mice. Further analysis showed a significantly (P<0.001) higher population of type I fibres in WT compared to Ts1Cje mice. Also, there was significantly (P<0.01) higher population of COX deficient fibres in Ts1Cje mice. Expression of Myf5 was significantly (P<0.05) reduced in triceps of Ts1Cje mice while MyoD expression was significantly (P<0.05) increased in quadriceps of Ts1Cje mice.
CONCLUSION: Ts1Cje mice exhibited weaker muscle strength. The lower population of the type I fibres and higher population of COX deficient fibres in Ts1Cje mice may contribute to the muscle weakness seen in this mouse model for DS.
Human bone marrow-derived MSCs spontaneously express specific Schwann cell markers

Ramli K, Aminath Gasim I, Ahmad AA, Hassan S, Law ZK, Tan GC, et al.

Cell Biol Int, 2019 Mar;43(3):233-252.
PMID: 30362196 DOI: 10.1002/cbin.11067

In peripheral nerve injuries, Schwann cells (SC) play pivotal roles in regenerating damaged nerve. However, the use of SC in clinical cell-based therapy is hampered due to its limited availability. In this study, we aim to evaluate the effectiveness of using an established induction protocol for human bone marrow derived-MSC (hBM-MSCs) transdifferentiation into a SC lineage. A relatively homogenous culture of hBM-MSCs was first established after serial passaging (P3), with profiles conforming to the minimal criteria set by International Society for Cellular Therapy (ISCT). The cultures (n = 3) were then subjected to a series of induction media containing β-mercaptoethanol, retinoic acid, and growth factors. Quantitative RT-PCR, flow cytometry, and immunocytochemistry analyses were performed to quantify the expression of specific SC markers, that is, S100, GFAP, MPZ and p75 NGFR, in both undifferentiated and transdifferentiated hBM-MSCs. Based on these analyses, all markers were expressed in undifferentiated hBM-MSCs and MPZ expression (mRNA transcripts) was consistently detected before and after transdifferentiation across all samples. There was upregulation at the transcript level of more than twofolds for NGF, MPB, GDNF, p75 NGFR post-transdifferentiation. This study highlights the existence of spontaneous expression of specific SC markers in cultured hBM-MSCs, inter-donor variability and that MSC transdifferentiation is a heterogenous process. These findings strongly oppose the use of a single marker to indicate SC fate. The heterogenous nature of MSC may influence the efficiency of SC transdifferentiation protocols. Therefore, there is an urgent need to re-define the MSC subpopulations and revise the minimal criteria for MSC identification.
Efficacy of Human Cell-Seeded Muscle-Stuffed Vein Conduit in Rat Sciatic Nerve Repair

Ramli K, Gasim AI, Ahmad AA, Htwe O, Mohamed Haflah NH, Law ZK, et al.

Tissue Eng Part A, 2019 10;25(19-20):1438-1455.
PMID: 30848172 DOI: 10.1089/ten.TEA.2018.0279

We investigated the efficacy of a muscle-stuffed vein (MSV) seeded with neural-transdifferentiated human mesenchymal stem cells as an alternative nerve conduit to repair a 15-mm sciatic nerve defect in athymic rats. Other rats received MSV conduit alone, commercial polyglycolic acid conduit (Neurotube®), reverse autograft, or were left untreated. Motor and sensory functions as well as nerve conductivity were evaluated for 12 weeks, after which the grafts were harvested for histological analyses. All rats in the treatment groups demonstrated a progressive increase in the mean Sciatic Functional Index (motor function) and nerve conduction amplitude (electrophysiological function) and showed positive withdrawal reflex (sensory function) by the 10th week of postimplantation. Autotomy, which is associated with neuropathic pain, was severe in rats treated with conduit without cells; there was mild or no autotomy in the rats of other groups. Histologically, harvested grafts from all except the untreated groups exhibited axonal regeneration with the presence of mature myelinated axons. In conclusion, treatment with MSV conduit is comparable to that of other treatment groups in supporting functional recovery following sciatic nerve injury; and the addition of cells in the conduit alleviates neuropathic pain. Impact Statement It is shown that pretreated muscle-stuffed vein conduit is comparable to that of commercial nerve conduit and autograft in supporting functional recovery following peripheral nerve injury. The addition of neural-differentiated mesenchymal stem cells in the conduit is shown to alleviate neuropathic pain.