This paper chronicled the development of a locally produced bone graft substitute based on calcium phosphate bioceramics called "GranuMaS--from concepts to clinics, and finally to its successful commercialization all within 5-year duration. It was a Prioritized Research (PR) collaborative project of 5 institutions namely SIRIM, ANM, USM, UKM and IIUM, funded by MOSTI to the amount of approximately RM2.5 millions under RM8. This paper also highlighted the requirements needed in terms of technical expertise/manpower, facilities and infrastructure, and government/institutional supports, as well as the challenge faced in developing and commercializing such product.
In view of poor regeneration potential of the articular cartilage, in-vitro engineering of cartilage tissue offers a promising option for progressive joint disease. This study aims to develop a biologically engineered articular cartilage for autologous transplantation. The initial work involved determination of chondrocyte yield and viability, and morphological analysis. Cartilage was harvested from the knee, hip and shoulder joints of adult New Zealand white rabbits and chondrocytes were isolated by enzymatic digestion of the extra-cellular matrix before serial cultivation in DMEM/Ham's F12 media as monolayer cultures. No differences were noted in cell yield. Although chondrocytes viability was optimal (>93%) following harvest from native cartilage, their viability tended to be lowered on passaging. Chondrocytes aggregated in isogenous colonies comprising ovoid cells with intimate intracellular contacts and readily exhibited Safranin-O positive matrix; features typically associated with articular cartilage in-vivo. However, chondrocytes also existed concurrently in scattered bipolar/multipolar forms lacking Safranin-O expression. Therefore, early data demonstrated successful serial culture of adult chondrocytes with differentiated morphology seen in established chondrocyte colonies synthesizing matrix proteoglycans.
This in vivo study revealed that porous hydroxyapatite (PHA) and dense hydroxyapatite (DHA) are good implant materials that can accelerate bone healing and resorbed in acceptable time. But there were differences in the mechanism of the resorption of DHA and PHA due to variability in the physical properties and osteogenicity.
Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.
This study is to qualitatively evaluate a locally produced hydroxyapatite (HA), made by AMREC-SIRIM in an experimental animal bone defect using New Zealand White (NZW) rabbits. HA cylindrical blocks measuring 2.5 mm (D) x 1.0 mm (H) were implanted in the rabbits' left tibia. The tibias were harvested within one to three weeks post-implantation. The implantion site was cut into thin undecalcified sections of about 30 microm to 60 microm and stained with Toluidine Blue and Goldner's Masson Trichrome. Microscopic examinations using standard light microscopy of these slides were performed.
The main objective of the study was to determine the biodegradability, resorption and osteoconductivity potency of coral implant. Coral blocks (CORAGRAF) were prepared from sea coral Porites species. The blocks were implanted in the right mandible of rabbit model. Implants were harvested at 2 and 4 weeks intervals and subjected for light and scanning electron microscopy. Dense hydroxyapatite (DHA) was implanted in the left mandible as a control. The results of this study demonstrated that CORAGRAF is a good implant material that can accelerates bone healing and be resorbed in an acceptable time. The mechanisms of the resorption seemed to be the same (crumbling process), a first step where the edge of the coral become powdery then a second step which could be phagocytosis and dissolution in extracellular fluid.
Metallic materials implanted into bone defects are generally encapsulated by a fibrous tissue. Some metallic materials such as titanium and tantalum, however, have been revealed to bond to the living bone without forming the fibrous tissue, when they were subjected to NaOH solution and heat treatments. Thus treated metals form bone tissue around them even in muscle, when they take a porous form. This kind of osteoconductive and osteoinductive properties are attributed to sodium titanate or tantalate layer on their surfaces formed by the NaOH and heat treatments. These layers induce the deposition of bonelike apatite on the surface of the metals in the living body. This kind of bioactive metals are useful as bone substitutes even highly loaded portions, such as hip joint, spine and tooth root.
Management of severe tracheal anomalies remains a clinical challenge. Tissue engineering offers new hope in trachea reconstruction surgery. However to date no optimal technique achieved in the formation of human or animal trachea. The main problem lies on the biomaterial used and the complex city of forming trachea in vivo. This study was aimed at creating tissue-engineered trachea cartilage from easily accessible human and animal nasal septum cartilage using internal scaffold and biodegradable human and animal fibrin.
A study of nerve regeneration through a 1cm defect in the peroneal component of the sciatic nerve was performed on sixteen rabbits. Either silicone or polytetrafluoroethylene (PTFE) tubes or nerve graft were used to bridge the defect and the opposite limb was not operated upon. The rabbits that underwent nerve grafting had favourable findings. In the PTFE group, a nerve-like structure was seen at the former gap site and histology confirmed viable axons within the tubes and distal to the repair site. In the silicone tube group, there were no myelinated axons demonstrated. The axonal count for the grafted nerves and the nerves repaired with PTFE tube are on average 80.4% and 38.2% of that of the unoperated nerve, respectively. On average, the percentage anterior compartment muscle weight (expressed as a percentage of the unoperated limb) for the silicone, PTFE and nerve graft groups are 42.3%, 42.1%, and 72.7% respectively. The results show that although, PTFE conduits can bridge a nerve defect of 1cm, nerve grafting provides a superior and more predictable outcome.
Conjoined twins in a triplet pregnancy is an extremely rare occurrence. We present here, a 27-year-old multigravida with gestational diabetes and a conjoined twins in a triplet pregnancy.
Comment on: Teoh MK, Chong JM, Mohamed J, Phang KS. Protection by tocotrienols against hypercholesterolaemia and atheroma. Med J Malaysia. 1994 Sep;49(3):255-62
Antioxidants such as tocotrienols may protect against atherosclerosis since tissue injury from free radicals is a final common pathway of damage in arterial disease. In this study, the effects of tocotrienols on serum cholesterol, lipid peroxides, and aorta atheroma were assessed in rabbits fed an atherogenic diet for 12 weeks. Tocotrienols were more effective than tocopherols in preventing increases in serum LDL (p = 0.03) and total cholesterol (p = 0.008) levels in the cholesterol-fed rabbits. Elevation of serum lipid peroxides was effectively suppressed by tocotrienols (p = 0.01). Both tocopherols and tocotrienols offered significant protection against atheroma in the rabbit aorta, but tocotrienols had a stronger hypolipidaemic effect.
Comment in: Pathmanathan R, Wong KT. Protection by tocotrienols against hypercholesterolaemia and atheroma. Med J Malaysia. 1995 Mar;50(1):117