Biomedical subjects

J C Y Cheng

Publications and source records attributed to J C Y Cheng.

16 recordsLinked to original sources

PubMed2006

Curve correction effect of rigid spinal orthosis in different recumbent positions in adolescent idiopathic scoliosis (AIS): a pilot MRI study.

In this pilot cross-sectional study, the effectiveness of rigid spinal orthoses in the correction of spinal curvature of 14 patients with moderate adolescent idiopathic scoliosis (AIS) at different recumbent positions (supine, prone, right and left decubitus) was investigated. Using magnetic resonance (MR) imaging and multi-planar reconstruction technique, evaluation of the scoliotic spine in the coronal, sagittal and axial planes and the effect of spinal orthosis on AIS at different recumbent positions was studied. There was significant reduction of coronal Cobb's angle (p < 0.05) with bracing at all four recumbent positions and the maximal reduction was found in the prone position (18% reduction). The sagittal Cobb's angle was only significantly reduced at the supine position while the axial rotation did not change significantly in all positions.

Adolescent↗

PubMed2006

The role of melatonin receptor 1B gene (MTNR1B) in adolescent idiopathic scoliosis--a genetic association study.

UNLABELLED: Many studies have demonstrated the role of melatonin in the etiology of AIS. Previous studies have shown that there is no evidence of mutations in the melatonin receptor 1A gene in AIS patients. In this study, we have examined the role of melatonin receptor 1B in predisposition for AIS. Using haplotype block tagging technique, a set of tagging SNPs were defined for MTNR1B from the Han Chinese data of the International HapMap project. The association between the tagging of single nucleotide polymorphisms (tSNPs) in MTNR1B region and the occurrence of AIS was studied. METHOD: 473 AIS girls and 311 normal controls were recruited. The age range of the patients was between 10 and 18 years old. The maximum Cobb was recorded at latest follow-up in AIS patients. Three of five tSNPs were studied; they were all located within the coding region of the MTNR1B gene. RESULTS: There was no significant difference in the genotype or allelic frequencies (AF) of the 3 tSNPs between AIS and controls. In a case-only analysis, no difference in curve severity in AIS patients was found among patients with different genotypes (by one-way ANOVA). DISCUSSION: The 3 tSNPs showed no association with either the occurrence of AIS or the maximum Cobb angle within AIS girls. Further analysis of the remaining tSNPs within the regulatory region of the MTNR1B gene and other related genes in the melatonin signaling pathway may provide further information on the role of the melatonin in AIS girls.

Adolescent↗

PubMed2006

Genetic association study of insulin-like growth factor-I (IGF-I) gene with curve severity and osteopenia in adolescent idiopathic scoliosis.

UNLABELLED: IGF-I has a pivotal role in bone growth and could be one of the putative disease-modifier genes in AIS. Two SNPs in IGF-I gene promoter region were studied for any association with occurrence of AIS and for their effect on the curve severity among AIS. METHODS: 506 AIS girls (Cobb>20 degrees) and 227 age-matched Chinese girls were recruited. The spine (L2-L4) and hip BMD of the subjects were measured by DXA. A subgroup of AIS patients (N=340) who were followed-up to skeletal maturity and the maximum Cobb's angle was recorded. Two SNPs were genotyped by PCR-RFLP (rs5742612 and rs2288377). The chi-square test and one-way ANOVA were used to test the association between genotypes and quantitative parameters, respectively. RESULTS: No association was between the genotypes and the occurrence of AIS and the BMD of the spine and hip. The allelic frequency of T allele was 0.69 in AIS and control. However, the Cobb's angle was higher in patients with the homozygous T allele (Mean Cobb's angle: 38.1 degrees in TT vs 35.9 degrees in TC vs 33.2 degrees in CC group; p=0.04). DISCUSSION: Interestingly, IGF-I polymorphism affects the curve severity of AIS though it was not associated with onset of AIS per se. It indicates that IGF-I may be a disease modifying gene. The importance of IGF-I in skeletal growth makes it a good candidate gene which would play a role in the documented association of rapid growth with curve progression in AIS.

Adolescent↗

PubMed2006

Persistent osteopenia in adolescent idiopathic scoliosis--longitudinal monitoring of bone mineral density until skeletal maturity.

The aim of this study was to monitor BMD changes occurring during periods of rapid growth and to investigate whether osteopenia was a persistent phenomenon in skeletally matured AIS girls. 196 AIS Chinese girls and 122 healthy controls, aged 11-16, were follow-up for 3.5 years. Bilateral femoral neck bone mineral density (BMD) and volumetric BMD (vBMD) of the distal tibia were obtained by dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Osteopenia was defined if the age-adjusted BMD was below or equal to -1 standard deviation (SD). The average age at the final follow-up was 16.8 years old. The median initial Cobb angle for this group of patients was 26 degrees. The prevalence of osteopenia at the baseline measurement was 35.9%. Longitudinal BMD results demonstrated that 86.0% of osteopenic AIS girls had persistently low BMD at the time of skeletal maturity (age of 16). vBMD of distal tibia of AIS was significantly lower than that of the controls throughout the age of 13 to 17 during the period of rapid growth. In addition, there were also significant differences in vBMD among AIS (moderate and severe group) and the controls by one-way ANOVA (p<0.05). The present study for the first time revealed that over 86% of osteopenic AIS patients had persistently low BMD, at both distal tibia and femoral neck regions, at the time of skeletal maturity. Early detection and treatment of AIS-related osteopenia might help in maximizing peak bone mass during peripubertal growth that thereby minimizing risks of developing osteoporotic fractures later in life.

Adolescent↗

PubMed2006

Lower degree of mineralization found in cortical bone of adolescent idiopathic scoliosis (AIS).

UNLABELLED: A lowered bone mineral density (BMD) was observed in trabecular bone in a significant number of AIS patients. The present study aims at investigating whether lower BMD is a systemic phenomenon, which would also be present in the cortical component of long bone. SUBJECTS AND METHODS: 78 AIS girls (age:15-18y.o) with either moderate (Cobb: 20-40) or severe (Cobb: >40) curve and 44 age-matched controls were recruited. The BMD of the distal region and the mid-shaft of radius were measured with a multi-layer peripheral quantitative computed tomography (pQCT). The trabecular bone and cortical bone BMD and the morphology of mid-shaft were compared. RESULTS: Both trabecular and cortical BMD in severe AIS group was significantly lower than the control by 8.7% and 1.7% (p<0.05 for both), respectively. However, the cortical bone area of the mid-shaft did not show any differences from the normal control subjects. DISCUSSION: This study demonstrates a systemic low BMD including the cortical bone. It is suggested that AIS girls may have disturbance in mineralization and ossification during peripubertal growth.

Adolescent↗

PubMed2005

Bone mineral density and calcium metabolism of Hong Kong Chinese postpartum women--a 1-y longitudinal study.

OBJECTIVE: This paper reports longitudinal changes in bone mineral density (BMD), calcium homeostasis and dietary calcium intake in a group of Hong Kong breastfeeding women during the first year postpartum. DESIGN AND SUBJECTS: Nine mothers who breastfed exclusively or almost exclusively for at least 3 months and 14 formula feeding mothers aged 20-40 y were interviewed after delivery, 2 and 6 weeks, 3, 6 and 12 months postpartum. BMD at L2-L4 lumbar spine (LS), trochanter (Tro) and femoral neck (FN), serum intact parathyroid hormone (iPTH), serum bone-specific alkaline phosphatase (b-ALP), urinary deoxypyridinoline (Dpd), serum and urinary calcium (Ca) and phosphorus (P) and dietary intake of macronutrients were assessed. RESULTS: Compared to the formula feeding group, BMD assessed at LS, Tro and FN decreased significantly in the breastfeeding group over the first 6 months, with rebound to approximate baseline values at 12 months for the latter two sites. Serum iPTH increased in both groups, whereas serum b-ALP was consistently higher in the breastfeeders. Urinary Ca and P excretion decreased early postpartum in both groups, but the breastfeeders had higher excretion at 3 and 6 months. Breastfeeding mothers consumed significantly more Ca than the formula feeding mothers in the early postpartum. CONCLUSIONS: Increased calcium requirement during early lactation is affected through mobilisation of bone and renal calcium conservation. Bone mineral loss during lactation is temporary. Further studies are warranted to investigate the effects of diet and other hormonal factors on the calcium homeostasis during lactation.

Adult↗

PubMed2005

A cross-sectional study on the development of foot arch function of 2715 Chinese children.

A cross-sectional study was conducted to investigate the foot arch function of Chinese children. A total of 2715 children, 1246 girls, and 1369 boys, 4-18 years of age were recruited from kindergartens, primary, and secondary schools. The dynamic footprints of the children were collected using a portable pressure-sensing mat. The Contact Force Ratio (CFR, i.e. the ratio of the mid-foot loading to the total loading of the contacted foot, with the toes ignored) of each age group was calculated. In general, the CFR decreased from 4 to 10 years and plateaued at 10-12 years and then increased until 15-16 years. An abnormal low arch foot was defined as the foot that had a CFR value larger than the corresponding age mean plus one standard deviation. The cut-off CFR values of each age group were calculated. With the exception of the 17 years age group, which consisted of a relatively small number of subjects, the percentage of low arch subjects of all the other age groups ranged from 15 to 20%.

Adolescent↗

PubMed2005

A work study of the CAD/CAM method and conventional manual method in the fabrication of spinal orthoses for patients with adolescent idiopathic scoliosis.

A study was conducted to compare the CAD/CAM method with the conventional manual method in fabrication of spinal orthoses for patients with adolescent idiopathic scoliosis. Ten subjects were recruited for this study. Efficiency analyses of the two methods were performed from cast filling/ digitization process to completion of cast/image rectification. The dimensional changes of the casts/ models rectified by the two cast rectification methods were also investigated. The results demonstrated that the CAD/CAM method was faster than the conventional manual method in the studied processes. The mean rectification time of the CAD/CAM method was shorter than that of the conventional manual method by 108.3 min (63.5%). This indicated that the CAD/CAM method took about 1/3 of the time of the conventional manual to finish cast rectification. In the comparison of cast/image dimensional differences between the conventional manual method and the CAD/CAM method, five major dimensions in each of the five rectified regions namely the axilla, thoracic, lumbar, abdominal and pelvic regions were involved. There were no significant dimensional differences (p < 0.05) in 19 out of the 25 studied dimensions. This study demonstrated that the CAD/CAM system could save the time in the rectification process and offer a relatively high resemblance in cast rectification as compared with the conventional manual method.

Adolescent↗

PubMed2005

A comparison of treatment effectiveness between the CAD/CAM method and the manual method for managing adolescent idiopathic scoliosis.

The treatment effectiveness of the CAD/CAM method and the manual method in managing adolescent idiopathic scoliosis (AIS) was compared. Forty subjects were recruited with twenty subjects for each method. The clinical parameters namely Cobb's angle and apical vertebral rotation were evaluated at the pre-brace and the immediate in-brace visits. The results demonstrated that orthotic treatments rendered by the CAD/CAM method and the conventional manual method were effective in providing initial control of Cobb's angle. Significant decreases (p < 0.05) were found between the pre-brace and immediate in-brace visits for both methods. The mean reductions of Cobb's angle were 12.8 degrees (41.9%) for the CAD/CAM method and 9.8 degrees (32.1%) for the manual method. An initial control of the apical vertebral rotation was not shown in this study. In the comparison between the CAD/CAM method and the manual method, no significant difference was found in the control of Cobb's angle and apical vertebral rotation. The current study demonstrated that the CAD/CAM method can provide similar result in the initial stage of treatment as compared with the manual method.

Adolescent↗

PubMed2005

Osteopenia: a new prognostic factor of curve progression in adolescent idiopathic scoliosis.

BACKGROUND: Studies have shown that 27% to 38% of girls with adolescent idiopathic scoliosis have systemic osteopenia. The aim of this study was to investigate whether osteopenia could serve as one of the important prognostic factors in predicting curve progression. METHODS: A prospective study was performed in 324 adolescent girls with adolescent idiopathic scoliosis who had a mean age of thirteen and a half years. Bone mineral density of the spine and both hips was measured at the time of the clinical diagnosis of scoliosis. All patients were followed longitudinally until skeletal maturity or until the curve had progressed > or =6 degrees . The univariate chi-square test and stepwise logistic regression were used to predict the prevalence of curve progression, and a receiver operating characteristic curve was plotted. RESULTS: The overall prevalence of curve progression was 50%. The prevalence of osteopenia at the spine and hips was 27.5% and 23.1%, respectively. A larger initial Cobb angle (odds ratio = 4.6), a lower Risser grade (odds ratio = 4.7), premenarchal status (odds ratio = 2.5), osteopenia in the femoral neck of the hip on the side of the concavity (odds ratio = 2.3), and a younger age at the time of diagnosis (odds ratio = 2.1) were identified as risk factors in predicting curve progression. A predictive model was established, and the area under the receiver operating characteristic curve of the model was 0.80 (p < 0.01). CONCLUSION: Osteopenia may be an important risk factor in curve progression. The measurement of bone mineral density at the time of diagnosis may serve as an additional objective measurement in predicting curve progression in adolescent idiopathic scoliosis. The bone mineral density-inclusive predictive model may be used in treatment planning for patients with adolescent idiopathic scoliosis who are at high risk of curve progression.

Adolescent↗

PubMed2004

Evaluation of the expression of collagen type I in porous calcium phosphate ceramics implanted in an extra-osseous site.

The aim of the present study is to demonstrate the newly formed tissue in calcium phosphate (Ca/P) ceramics after extra-osseous implantation by histological and immunohistochemistry (IHC) methods. Synthesis porous Ca/P ceramics without adding any growth factor and living cell were implanted in the dorsal muscle of dogs for 1 and 2 months. Undecalcified and decalcified sections were stained by hematoxylin and eosin (H&E), and IHC, respectively. The histological results showed the beginning of osteogenesis and angiogenesis after being implanted for 1 month and the obvious new bone formation after being implanted for 2 months. IHC were conducted via the avidin-biotin peroxidase complex (ABC) method and the primary antibody was collagen type I. IHC results indicated that collagen type I was expressed within osteoblast-like cells and newly formed bone-like tissue in Ca/P ceramics after 1 month, and in the mineralized matrix of newly formed bone and osteoblasts, some osteocytes and some lacunae after 2 months. No cartilage and chondrocytes were observed in the histological and IHC-stained sections. Evidence of intramembranous osteogenesis was confirmed.

Animals↗

PubMed2004

Contact force ratio: a new parameter to assess foot arch function.

Static footprint parameters have been used to quantify arch height with conflicting results. This could be caused by the inherent inaccuracy and variations of the methodology used. Since the foot is a dynamic structure that undergoes changes during a step, it is more desirable to capture and analyse the dynamic footprint at an instant during the gait cycle that can most closely reflect the weight-bearing foot function. Forty (40) volunteer subjects were recruited for the reliability test of a new parameter, the Contact Force Ratio (CFR), derived from dynamic footprint. This is a measure of midfoot loading during gait. The mid-gait dynamic footprints were collected using a pressure sensing mat. Results of ICC tests showed that the CFR had good intratester (0.918) and intertester (0.909) reliability. The validity of the method was examined by correlating the parameter to the functional change in arch height, i.e. the Navicular Drop between the non-weight-bearing and weight-bearing conditions.

Adult↗

PubMed2004

Orthotic design and foot impression procedures to control foot alignment.

The traditional theory on subtalar joint neutral position and intrinsic foot deformities for the evaluation and treatment of foot and ankle disorders has been the basis for foot orthotics for many years. Although clinical evaluations have suggested a relationship between subtalar pronation and a variety of lower limb problems, such as shin splints and anterior knee pain, recent research has raised serious concerns about the reliability and validity of the assessment and intervention methods. Results of recent studies in foot biomechanics suggest that the orthosis design to control foot alignment should stabilise the medial apical bony structure of the arch to control the first ray mobility and transmit load through the lateral support structures of the foot, locking the calcaneocuboid joint and decreasing strain in the plantar aponeurosis. The concept of "posting" according to a measured foot deformity is de-emphasised. Reliable foot impression procedures are required to provide appropriate orthotic design and thus management. A prone lying position manipulated foot impression method using polycaprolactone based low temperature thermoplastic material was introduced. Ten (10) subjects were recruited to participate in the reliability tests, which were conducted by 2 orthotists specialized in foot orthotics. Results showed high intrarater and interrater reliability of the measured forefoot width and the navicular height. The reliability of the forefoot-rearfoot relationship was demonstrated by the small variance of the root mean square calculation. Subsequently orthotic intervention can be done in a more consistent manner.

Calcium Sulfate↗

PubMed2003

The effect of hyaluronan on osteoblast proliferation and differentiation in rat calvarial-derived cell cultures.

Hyaluronan (or hyaluronic acid, HA) is an essential component of extracellular matrices. It interacts with other macromolecules and plays a predominant role in tissue morphogenesis, cell migration, differentiation, and adhesion. The cell signaling functions of HA are mediated through the CD-44 receptor and are dependent upon the molecular weight of the polymer. We hypothesized that an HA of appropriate molecular weight alone in optimal concentration may induce osteoblast differentiation and bone formation. Enzyme-digested calvarial-derived mesenchymal cells from 2-day-old newborn rats were cultured with the addition of HA of three different molecular weights (2300, 900, and 60 kDa). We added, 0.5, 1.0, and 2.0 mg/mL HA for each molecular weight to the medium at the first plating of cells. After 7 to 20 days in culture, cell proliferation and differentiation were evaluated by measuring thymidine incorporation, alkaline phosphatase activity, and osteocalcin gene expression. The effects of HA on bone formation were examined by using Alizarin red staining for mineralization. The results showed that low molecular weight HA (60 kDa) significantly stimulated cell growth, increased osteocalcin mRNA expression in a dose-dependent manner, but showed no apparent effects on alkaline phosphatase activity and bone mineralization. On the other hand, high-weight HA (900 and 2,300 kDa) significantly increased all the parameters examined, particularly alkaline phosphatase activity, in a dose-dependent manner and stimulated cell mineralization to 126% and 119% of the controls, respectively, in the 1.0 mg/mL dose. Our findings suggest that HA has a molecular weight-specific and dose-specific mode of action that may enhance the osteogenic and osteoinductive properties of bone graft materials and substitutes due to its stimulatory effects on osteoblasts.

Alkaline Phosphatase↗

PubMed2003

Unintentional residential child injury surveillance in Hong Kong.

OBJECTIVES: To provide an overall pattern of morbidity in unintentional residential childhood injuries (URCI) in Hong Kong. METHODOLOGY: A cross-sectional telephone survey of caregivers of children aged under 16-years and adolescents suffering from URCI and admitted to three selected local Accident and Emergency Departments. RESULTS: Falls, cuts and scalds were the most common external causes of URCI observed, while boys predominated in the sample population. Most of the observed URCI were of moderate to mild severity. Children of new immigrant mothers were more likely to receive first aid immediately after the incidents. Parents were aware of potentially injurious behaviour and intervened on occasion, but most resorted to verbal warnings only. CONCLUSIONS: Prevalence of falls among observed URCI offers evidence in support of the hypothesis that the high population density in Hong Kong plays an integral role in understanding mechanisms of morbidity. Parents show concern about URCI but often lack substantial action that modifies injury risk. Considering the local injury differentials, an active prevention effort such as behavioural intervention and education for parents may be useful.

Accident Prevention↗

PubMed2003

Relative anterior spinal overgrowth in adolescent idiopathic scoliosis. Results of disproportionate endochondral-membranous bone growth.

We undertook a comparative study of magnetic resonance imaging (MRI) vertebral morphometry of thoracic vertebrae of girls with adolescent idiopathic thoracic scoliosis (AIS) and age and gender-matched normal subjects, in order to investigate abnormal differential growth of the anterior and posterior elements of the thoracic vertebrae in patients with scoliosis. Previous studies have suggested that disproportionate growth of the anterior and posterior columns may contribute to the development of AIS. Whole spine MRI was undertaken on 83 girls with AIS between the age of 12 and 14 years, and Cobb's angles of between 20 degrees and 90 degrees, and 22 age-matched controls. Multiple measurements of each thoracic vertebra were obtained from the best sagittal and axial MRI cuts. Compared with the controls, the scoliotic spines had longer vertebral bodies between T1 and T12 in the anterior column and shorter pedicles with a larger interpedicular distance in the posterior column. The differential growth between the anterior and the posterior elements of each thoracic vertebra in the patients with AIS was significantly different from that in the controls (p < 0.01). There was also a significant positive correlation between the scoliosis severity score and the ratio of differential growth between the anterior and posterior columns for each thoracic vertebra (p < 0.01). Compared with age-matched controls, the longitudinal growth of the vertebral bodies in patients with AIS is disproportionate and faster and mainly occurs by endochondral ossification. In contrast, the circumferential growth by membranous ossification is slower in both the vertebral bodies and pedicles.

Adolescent↗