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Biomedical subjects

James H P Hui

Publications and source records attributed to James H P Hui.

9 recordsLinked to original sources
PubMed2007

Bone marrow-derived mesenchymal stem cells influence early tendon-healing in a rabbit achilles tendon model.

BACKGROUND: A repaired tendon needs to be protected for weeks until it has accrued enough strength to handle physiological loads. Tissue-engineering techniques have shown promise in the treatment of tendon and ligament defects. The present study tested the hypothesis that bone marrow-derived mesenchymal stem cells can accelerate tendon-healing after primary repair of a tendon injury in a rabbit model. METHODS: Fifty-seven New Zealand White rabbits were used as the experimental animals, and seven others were used as the source of bone marrow-derived mesenchymal stem cells. The injury model was a sharp complete transection through the midsubstance of the Achilles tendon. The transected tendon was immediately repaired with use of a modified Kessler suture and a running epitendinous suture. Both limbs were used, and each side was randomized to receive either bone marrow-derived mesenchymal stem cells in a fibrin carrier or fibrin carrier alone (control). Postoperatively, the rabbits were not immobilized. Specimens were harvested at one, three, six, and twelve weeks for analysis, which included evaluation of gross morphology (sixty-two specimens), cell tracing (twelve specimens), histological assessment (forty specimens), immunohistochemistry studies (thirty specimens), morphometric analysis (forty specimens), and mechanical testing (sixty-two specimens). RESULTS: There were no differences between the two groups with regard to the gross morphology of the tendons. The fibrin had degraded by three weeks. Cell tracing showed that labeled bone marrow-derived mesenchymal stem cells remained viable and present in the intratendinous region for at least six weeks, becoming more diffuse at later time-periods. At three weeks, collagen fibers appeared more organized and there were better morphometric nuclear parameters in the treatment group (p < 0.05). At six and twelve weeks, there were no differences between the groups with regard to morphometric nuclear parameters. Biomechanical testing showed improved modulus in the treatment group as compared with the control group at three weeks (p < 0.05) but not at subsequent time-periods. CONCLUSIONS: Intratendinous cell therapy with bone marrow-derived mesenchymal stem cells following primary tendon repair can improve histological and biomechanical parameters in the early stages of tendon-healing.

Achilles Tendon↗
PubMed2005

Idiopathic scoliosis in Singapore schoolchildren: a prevalence study 15 years into the screening program.

STUDY DESIGN: A point prevalence survey of 72,699 schoolchildren in four age groups was performed. OBJECTIVES: To determine the prevalence rates of idiopathic scoliosis and to compare with a previous prevalence study done 15 years earlier. SUMMARY OF BACKGROUND DATA: Prevalence rates for idiopathic scoliosis of 5 degrees or more in schoolchildren were established in a study performed in 1982. There have been no previous data on prevalence rate changes over time. METHODS: A total of 35,558 boys and 37,141 girls from randomly selected schools were screened for scoliosis. Those with scoliometer readings of more than 5 degrees underwent radiographic evaluation. Prevalence rates were calculated for scoliosis at a predefined Cobb angle of 10 degrees and 5 degrees , the latter for comparison with the previous prevalence study. Curve type and distribution, pubertal status, and symptoms were correlated with the prevalence data. RESULTS: Prevalence rates were 0.05% for girls and 0.02% for boys at 6 to 7 years of age, 0.24% for girls and 0.15% for boys at 9 to 10 years of age, 1.37% for girls and 0.21% for boys at 11 to 12 years of age, and 2.22% and 0.66%, respectively, for girls and boys at 13 to 14 years of age. The ratio of girls to boys increased from 1.6 at 9 to 10 years of age to 6.4 at 11 to 12 years of age. Thoracolumbar curves were the most common (40.1%), followed by thoracic curves (33.3%), double/triple curves (18.7%), and lumbar curves (7.9%). Older children had greater proportions of larger curves. Compared with the previous prevalence study in 1982, there was a significant increase in the prevalence rate in girls 11 to 12 years of age. Screening of 11- to 12- and 13- to 14-year-old girls detected curves in the range suitable for bracing, with nearly 96% and 32% of the age groups, respectively, still amenarche or within a year of menarche, and 57% and 34% of the age groups, respectively, having low Risser grades of 0, 1, and 2. CONCLUSIONS: The overall prevalence rate of idiopathic scoliosis in our school population in 1997 was 0.93% in girls and 0.25% in boys. The prevalence rates were low at 6 to 7 and 9 to 10 years of age but increased rapidly to 1.37% and 2.22% for girls at 11 to 12 and 13 to 14 years of age, respectively. The prevalence rate increased significantly in 11- to 12-year-old girls over a 15-year period from 1982 to 1997. Screening of 11- to 12- and 13- to 14-year-old girls identified a significant number who could benefit from brace treatment.

Adolescent↗
PubMedDate not supplied

Comparative study of the ability of mesenchymal stem cells derived from bone marrow, periosteum, and adipose tissue in treatment of partial growth arrest in rabbit.

This study evaluates the ability of MSCs isolated from different origins--bone marrow, periosteum, or fat--to treat partial growth arrest in immature (6-week-old) New Zealand White rabbits. Up to 50% of the medial half of the proximal physis of the tibia was excised in these New Zealand White rabbits. Three weeks later, the bony bridge was excised, and fibrin glue with and without MSCs were transferred into the physeal defect of different rabbits. Contralateral tibias, without undergoing operation, served as self-control. Four groups of rabbits were involved in the study. Each group was injected separately with bone marrow-derived MSCs (group I), periosteum-derived MSCs (group II), fat-derived MSCs (group III), and fibrin glue alone (control, group IV). The rabbits were killed 8 and 16 weeks postoperatively. Clinical, radiological, and histological analyses were subsequently performed. Similar proliferative rates for three MSCs were demonstrated on days 4, 7, and 11 of primary culture. However, MSCs derived from bone-marrow and periosteum appeared to be more homogeneous than that from fat. All MSCs demonstrated chondrogenic and osteogenic differentiation potentials in vitro. The tibias in groups I and II showed significant correction of varus angulation at 16 weeks. However, the varus angulation in group III remained significantly obvious when compared with group I (p < 0.05). The length discrepancies between operated and normal tibiae in groups I, II, and III were significantly corrected compared with control (p < 0.01). In conclusion, bone-marrow and periosteum yielded more homogenous MSCs than fat, providing better correction of physeal arrest in rabbits. The source of MSCs itself could influence the success in the treatment of growth arrest.

Adipose Tissue↗
PubMedDate not supplied

Medial approach for corrective osteotomy of cubitus varus: a cosmetic incision.

Osteotomies described previously to correct cubitus varus had been associated with unsatisfactory results such as a prominent lateral scar and condyle and injury to the triceps. The authors evaluated the results of a medial approach for the corrective osteotomy of 14 consecutive children (mean age 8.4 years) with cubitus varus. The incision was made medially and the ulnar nerve was identified and protected. An image intensifier was used to identify the wedge. Lateral closing wedge osteotomy was performed and secured with cross K-wires, and the distal fragment was translated medially to reduce the lateral prominence. Both hyperextension and internal rotation deformity could be corrected with the osteotomy. The mean carrying angle and hyperextension of the elbow of 19.3 degrees varus and 22.2 degrees were corrected to 2.4 degrees valgus and 8.8 degrees respectively. Radiographically, the Baumann's angle and the flexion angle were improved from 90.1 degrees to 77.3 degrees and 24.2 degrees to 37.2 degrees respectively. No patient had a prominent lateral condyle, and the operative scars were well concealed along the medial aspect of the elbow. There was one case of transient ulnar nerve paresis with residual varus.

Child↗
PubMedDate not supplied

Open reduction and annular ligament reconstruction with fascia of the forearm in chronic monteggia lesions in children.

Fifteen children with chronic Monteggia lesions were treated with open reduction, annular ligament reconstruction with fascia of the forearm, and ulnar osteotomy. Mean age was 8 years 3 months (range 3-16 years). The chronicity of missed Monteggia was from 6 weeks to 2 years (mean 12 weeks). All patients were classified as Bado type I, except one with Bado type III. Mean follow-up was 4 years 3 months after surgery. There was a loss of pronation in six cases with the mean of 16 degrees. However, only four cases had rotational loss; the others had a mean rotational arch increase of 5 degrees. The flexion arches improved in all patients, with a mean of 27.7 degrees. The functional result was excellent in 11 patients, good in 3 patients, and poor in 1 patient. This one-incision approach is safe in treating chronic Monteggia lesions in children.

Adolescent↗
PubMedDate not supplied

Changing glenoid version after open reduction of shoulders in children with obstetric brachial plexus palsy.

Twenty-three patients who had obstetric brachial plexus palsy and shoulder subluxation or dislocation that required open reduction and tendon lengthening were entered into a prospective study to evaluate glenoid version after surgery. All the patients had a preoperative computerized axial tomograph and postoperative computed tomography scan of both shoulders at approximately yearly intervals to assess the degree of congruity of the glenohumeral joint and glenoid version. Surgery was performed between 1988 and 1997. There were 11 girls and 12 boys. The mean age was 2 years 5 months (range 8 months-6 years 7 months). The left shoulder was affected in 12 patients and the right shoulder was affected in 11 patients. At mean follow-up of 3 years 7 months, the mean glenoid retroversion for the dislocated shoulder progressively decreased. The difference in glenoid version between the dislocated and the normal side decreased. The angle of glenoid retroversion in the affected shoulders decreased by a mean of 31% after open reduction, and the retroversion continued to improve at 9% per year.

Brachial Plexus Neuropathies↗
PubMedDate not supplied

Cultured mesenchymal stem cell transfers in the treatment of partial growth arrest.

Mesenchymal stem cells were cultured from periosteum harvested from the tibias of New Zealand White (NZW) rabbits. An experimental model for growth arrest was created by excising the medial half of the proximal growth plate of the tibia of 6-week-old NZW rabbits. The cultured mesenchymal stem cells were embedded in agarose and transferred into the growth-plate defect after excision of the bony bridge in established growth arrest. Transfer of agarose alone and a periosteum flap without cells served as the control groups. In cases of transfer of mesenchymal stem cells, growth arrest with angular deformation and loss of length of the tibia was corrected. Transfer of agarose alone and a periosteum flap yielded poor results.

Animals↗