In vivo chromosome aberration test for hydroxyapetite in mice.

This study evaluates the cytotoxic and mutagenic effect of synthetic hydroxyapatite granules (source: School of Material and Mineral Resources Engineering, Universiti Sains Malaysia) in the bone marrow cells of mice. Mice are exposed to synthetic hydroxyapatite granules, the bone marrow cells are collected and observed for chromosome aberrations. No chromosome aberrations were noticed in the animals exposed to distilled water (negative control) and to the test substance, synthetic hydroxyapatite granules (treatment) groups. Chromosome aberrations were observed in the animals exposed to Mitomycin C (positive control group). There was no indication of cytotoxicity due to synthetic hydroxyapatite granules in the animals as revealed by the mitotic index. Hence, synthetic hydroxyapatite granules are considered non-mutagenic under the prevailing test conditions.

Chromosome aberration test for hydroxyapatite in sheep.

The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.

Microsatellite instability and loss of heterozygosity in oral squamous cell carcinoma in Malaysian population.

Loss of heterozygosity (LOH) and microsatellite instability (MSI) have been documented as important events in oral squamous cell carcinoma (OSCC). Five microsatellite markers D3S192, D3S966, D3S647, D3S1228 and D3S659 were selected on chromosome 3p because of high frequency of alterations reported in head and neck squamous cell carcinoma and the involvement of von Hippel Lindau (VHL) at 3p25-26 and the fragile histidine triad (FHIT) at 3p14.2 genes proven in many tumour types. A total of 50 archival tissue samples of OSCC and corresponding normal samples were analyzed for LOH and MSI status. The overall LOH for the markers selected on 3p was 56 out of 189 informative cases (29.6%). The most frequent LOH was identified for the marker D3S966 which was 18/42 (42.8%) of informative cases suggesting the presence of putative tumour suppressor genes (TSGs) in this loci. In this study, high frequency of microsatellite instability was found in D3S966 which was 28.6% of informative cases; this reveals the possibility of mutations of MMR genes in this region. Frequent microsatellite alterations (MA) were observed in 3 markers D3S966 (71.4%), D3S1228 (56.7%) and D3S192 (41.0%). There was no significant association between LOH with gender, tumour stages and differentiation grades. However, there was a significant association between tumour stage and differentiation grades with MSI status in OSCC in Malaysian population with p values of 0.002 and 0.035, respectively. There was also a significant association between MA and differentiation grades (p=0.041).

Proliferative activity of cells from remaining dental pulp in response to treatment with dental materials.

BACKGROUND: The biological examination of pulp injury, repair events and response of dental pulp stem cells to dental restorative materials is important to accomplish restorative treatment, especially to commonly used dental materials in paediatric dentistry, such as glass ionomer cement (GIC) and calcium hydroxide (Ca(OH)(2)) lining cement. METHODS: Healthy patients aged between 9 to 11 years with carious primary molars without pulp exposure were selected and divided into two groups: Group 1 (teeth restored with GIC) and Group 2 (teeth lined using Ca(OH)(2) and restored with GIC). The proliferative activity of stem cells of teeth between these two groups was compared using colourimetric cell proliferation reagent, alamarBlue. Immunocytochemistry and flow cytometry confirmation were performed using mesenchymal stem cell markers, CD105 and CD166. RESULTS: The proliferative activity using alamarBlue assay showed that cells derived from the remaining dental pulp of exfoliated deciduous teeth were positive for CD105 and CD166 and exhibited no difference between the two groups. CONCLUSIONS: It can be concluded that the use of Ca(OH)(2) or GIC as a lining material in indirect pulp capping procedures has the same effect on cells derived from the remaining dental pulp of exfoliated deciduous teeth which have responded favourably to the restorative treatments.

Clinical manifestations in trisomy 9.

Complete trisomy 9 is a lethal diagnosis and most fetuses diagnosed thus die prenatally or during the early postnatal period and majority of such cases have been known to end in spontaneous abortion in the first trimester itself. One such rare survival of fetus ending in normal delivery and surviving until 20 days is reported here detailing the clinical manifestations of the child during the period of survival. The salient clinical features observed were small face, wide fontanel, prominent occiput, micrognathia, low set ears, upslanting palpebral fissures, high arched palate, short sternum, overlapping fingers, limited hip abduction, rocker bottom feet, heart murmurs and also webbed neck, characteristic of this trisomy 9 syndrome.

Gene expression analysis of osteoblasts seeded in coral scaffold.

Coral matrix of Porites sp. has the suitable properties for bone cell growth. This study was aimed to study the gene expression levels of osteoblast specific genetic markers; RUNX2, osteopontin, alkaline phosphatase and osteocalcin from osteoblasts seeded in coral scaffold, which are important in determining the feasibility of osteoblasts. Human osteoblasts were inoculated onto the processed coral in Dulbecco's Minimum Essential Medium. The cells were trypsinized on day 1, 7, 14, 18, and 21 and added with RNALater for preservation of RNA in cells. The RNA was extracted using commercial RNA extraction kit and the respective genes were amplified using RT-PCR kit and analyzed qualitatively on 1.5% agarose gel. The expressions were evaluated with the Integrated Density Value based on the intensity of band for different periods of cell harvest. Increased expressions of the RUNX2, osteopontin, alkaline phosphatase and osteocalcin genes in the present study proved that coral is a favorable carrier for osteogenetically competent cells to attach and remain viable.

Turner syndrome diagnosed in northeastern Malaysia.

INTRODUCTION: Turner syndrome affects about one in 2,000 live-born females, and the wide range of somatic features indicates that a number of different X-located genes are responsible for the complete phenotype. This retrospective study highlights the Turner syndrome cases confirmed through cytogenetic analysis at the Human Genome Centre of Universiti Sains Malaysia, from 2001 to 2006. METHODS: Lymphocyte cultures were set up using peripheral blood samples, chromosomes were prepared, G-banded, karyotyped and analysed in accordance to guidelines from the International System for Human Cytogenetic Nomenclature. RESULTS: The various karyotype patterns observed were 45,X; 46,X,i, (Xq); 45,X/45,X,+mar; 45,X/46,X,i,(Xq) and 45,X/46,XY. The mean age of our patients with Turner syndrome was 21 years, and the most common clinical features encountered in all these patients were short stature (100 percent), primary amenorrhoea (85.7 percent), absence of secondary sexual characteristics (57.1 percent), scanty pubic and axillary hair (50 percent), webbed neck (42.9 percent), wide carrying angle (42.9 percent), rudimentary uterus with bilateral streak ovaries (42.9 percent), underdeveloped breasts (35.7 percent) and wide-spaced nipples (21.4 percent). CONCLUSION: Even though there is no causal therapy for Turner syndrome, management and treatment are possible for malformations and conditions associated with it. In addition, counselling of the parents and of the patients themselves are necessary. Hence, establishing an early diagnosis, educating and increasing awareness among doctors, and if possible, a prenatal diagnosis, will help in early intervention, genetic counselling and in improving the quality of life in these patients.

Detection of beta-globin gene mutations among Kelantan Malay thalassaemia patients by polymerase chain reaction restriction fragment length polymorphism.

INTRODUCTION: Beta-thalassaemia major is an autosomal recessive disorder that results in severe microcytic, hypochromic, haemolytic anaemia among affected patients. Beta-thalassaemia has emerged as one of the most common public health problems in Malaysia, particularly among Malaysian Chinese and Malays. This study aimed to observe the spectrum of mutations found in Kelantan Malay beta-thalassaemia major patients who attended the Paediatrics Daycare Unit, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, the data of which was being used in establishing the prenatal diagnosis in this Human Genome Centre. METHODS: This was a cross-sectional study conducted with 35 Kelantan Malay beta-thalassaemia major patients. DNA was extracted from the blood collected from the patients and subjected to polymerase chain reaction (PCR) amplification. Six restriction enzymes were used to digest the PCR products for the detection of mutations. RESULTS: Five out of the six beta-globin gene defects were detected, namely, IVS-1 nt5 (G>C), IVS-1 nt1 (G>T), codon 26 (G>A), codon 41-42 (4 bp del) and codon 19 (A>G). The mutation which was not observed in this study was in codon 15 (G>A). The two most common mutations observed were codon 26 (G>A) and IVS-1 nt5 (G>C), which was detected in 26 and 17 patients, respectively. Two patients did not show any of the six mutations. CONCLUSION: Our results added to the existing data on the common beta-globin gene defects in Kelantan Malay beta-thalassaemia patients.

Cytogenetic and clinical profile of Down syndrome in Northeast Malaysia.

INTRODUCTION: This study was designed to evaluate the karyotype pattern, clinical features and other systemic anomalies of patients with Down syndrome in Malaysia. METHODS: Retrospective analysis was performed on the case records of 149 patients confirmed as Down syndrome by cytogenetic analysis at Human Genome Centre and Genetic Clinic at the Universiti Sains Malaysia. RESULTS: Among the 149 cases of Down syndrome presenting over a period of 4.2 years, free trisomy (non-disjunction) was present in 141 cases (94.6 percent). One case (0.7 percent) had translocation, and seven cases (4.7 percent) were mosaics. Average age at presentation was 10.6 months. Average maternal age at birth of the affected child was 32.3 years. The prominent craniofacial features noted were upslanting palpebral fissures (89.3 percent), flat facial profile (64.9 percent), low set ears (56.1 percent), epicanthic folds (17.5 percent) and protruding tongue (19.2 percent). A total of 52.6 percent of the cases had documented hypotonia. Characteristic limb and dermatoglyphic anomalies included short stubby fingers (24.5 percent), sandal gap (33.3 percent), unilateral or bilateral simian crease (36.8 percent) and clinodactyly (19.2 percent). Ophthalmological abnormalities, such as hypertelorism, were presented in 33.3 percent of the cases. Congenital heart disease was diagnosed in 35 out of 71 cases (49.3 percent) and gastrointestinal anomalies were noted in 18 out of 79 cases (22.7 percent) analysed. CONCLUSION: Efforts to establish early diagnosis and a proper screening for high association with systemic anomalies should be undertaken among the Down syndrome patients in this population.