Biomedical subjects

Fuk-Tan Tang

Publications and source records attributed to Fuk-Tan Tang.

8 recordsLinked to original sources

PubMed2005

Ultrasound stimulation of tendon cell proliferation and upregulation of proliferating cell nuclear antigen.

Therapeutic ultrasound has been widely used in sports-related tendon injuries. However, previous research has not examined the molecular mechanism of this therapeutic effect on tendon cell proliferation. This study was designed to determine the in vitro effect of ultrasound on the proliferation of tendon cells intrinsic to rat Achilles tendon. Furthermore, the existence of a correlation between this effect and the expression of the proliferating cell nuclear antigen (PCNA) was also examined. Using cultured tendon cells, cell viability was evaluated by MTT assay. The expression of PCNA protein in cells was evaluated by immunocytochemistry. The mRNA expression of PCNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). A dose-dependent increase in the cellularity of tendon cells by either pulsed or continuous mode ultrasound was demonstrated by MTT assay (p=0.044 for the pulsed mode; p=0.004 for the continuous mode). Ten minutes of treatment achieved maximum cellularity compared to 5 min of treatment time (p=0.010 for pulsed ultrasound; p=0.004 for continuous ultrasound). Immunocyto-chemical staining revealed that ultrasound treated tendon cells were stained more strongly for PCNA than were control cells. Upregulation of PCNA at the mRNA level was also confirmed by RT-PCR. In conclusion, ultrasound stimulates tendon cell proliferation in a process that is probably mediated by the upregulation of PCNA.

Achilles Tendon↗

PubMed2004

Infrared-based communication augmentation system for people with multiple disabilities.

PURPOSE: This study describes an eyeglass-type infrared-based communication board for the nonspeaking with quadriplegia. METHOD: This system is composed of four major components: a headset, an infrared transmitting module, an infrared receiving/signal-processing module, and a main controller, the Intel-8951 microprocessor. This design concept was based on the use of an infrared remote module fastened to the eyeglasses which could allow the convenient control of the input motion on the keys of a communication board, which are all modified with infrared receiving/signal-processing modules. For system evaluation, 12 subjects (all men, 21-45 years old, six normal subjects as the control group and six nonspeaking with quadriplegia as the experimental group) were recruited. RESULTS: The average accuracy of the control group and the experimental group were 93.1 +/- 4.3% and 89.7 +/- 5.5%, respectively. The average time cost of the control group and the experimental group were 78.3 +/- 8.7 s and 89.9 +/- 10.2 s, respectively. An independent t-test revealed that the differences in the average accuracy and the average time cost of the control group and the experimental group were not significant (p>0.05). CONCLUSIONS: The increase of opportunity to communicate using the infrared-based communication board would help people with multiple disabilities to socialize actively.

Adult↗

PubMed2004

Ibuprofen inhibition of tendon cell proliferation and upregulation of the cyclin kinase inhibitor p21CIP1.

Sports-related tendon injuries are commonly treated with nonsteroidal antiinflammatory drugs. This study was designed to determine the in vitro effect of ibuprofen on the proliferation of tendon cells intrinsic to rat Achilles tendon. Furthermore, the existence of a correlation between this effect and the expression of the cyclin kinase inhibitor p21(CIP1) and retinoblastoma (Rb) protein was also examined. Using cultured tendon cells, cell viability was evaluated by MTT assay. To determine whether apoptosis was related to the effect of ibuprofen, terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay was used. The mitotic index (MI) was calculated from the number of cells in the mitotic phase as stained and identified by propidium iodide. The mRNA expression of p21(CIP1) was determined by reverse transcription-polymerase chain reaction (RT-PCR). Protein expressions of p21(CIP1) and Rb protein were determined by Western blot analysis. A dose-dependent decrease in the cellularity of tendon cells by ibuprofen was demonstrated by MTT assay (p<0.001). However, TUNEL assay revealed no evidence of apoptosis. Ibuprofen dose-dependently reduced the MI (p<0.001). Upregulation of p21(CIP1) both at the levels of mRNA expression and protein was revealed from RT-PCR and Western blot analyses. The inhibition of Rb protein phosphorylation was also noted in ibuprofen-treated cells. In conclusion, ibuprofen inhibits tendon cell proliferation in a process that is probably mediated by the upregulation of p21(CIP1) and reduced phosphorylation of Rb protein.

Animals↗

PubMed2003

Effects of total contact insoles on the plantar stress redistribution: a finite element analysis.

OBJECTIVE: To investigate the effects of total contact insoles on the plantar stress redistribution using three-dimensional finite element analysis. DESIGN: The efficacies of stress reduction and redistribution of two total contact insoles with different material combinations were compared with those of a regular flat insole used as a baseline condition. BACKGROUND: Many specially designed total contact insoles are currently used to reduce the high plantar pressure in diabetic patients. However, the design of total contact insoles is mostly empirical and little scientific evidence is available to provide a guideline for persons who prescribe such insoles. METHODS: To use three-dimensional finite element models of the foot together with insoles to investigate the effects of total contact insoles on the foot plantar pressure redistributions. Nonlinear foam material properties for the different insole materials and the contact behavior in the foot-insole interface were considered in the finite element analysis. RESULTS: Results showed that the peak and the average normal stresses were reduced in most of the plantar regions except the midfoot and the hallux region when total contact insoles were worn compared with that of the flat insole condition. The reduction ratios of the peak normal stress ranged from 19.8% to 56.8%. CONCLUSIONS: Finite element analysis results showed that the two sets of total contact insoles used in the current study can both reduce high pressures at regions such as heel and metatarsal heads and can redistribute the pressure to the midfoot region when compared with the flat insole condition. RELEVANCE: It is possible to simulate foot deformities, change in material properties, different ambulatory loading conditions, and different orthotic conditions by altering the finite element model in a relatively easy manner and these may be of interests to the medical professionals who treat foot-related problems.

Adult↗

PubMed2003

Inhibition of tendon cell migration by dexamethasone is correlated with reduced alpha-smooth muscle actin gene expression: a potential mechanism of delayed tendon healing.

Local corticosteroid injection is commonly used to treat sports-related tendon injuries. However, isolated cases of tendon rupture following injection suggest that this treatment may impair the healing process. Tendon healing requires the migration of tendon cells to the repair site, followed by the proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of dexamethasone on the migration of tendon cells intrinsic to rat Achilles tendon at concentrations similar to those typically used for local injection treatment. Furthermore, the existence of a correlation between this effect and the expression of the contractile actin isoform, alpha-smooth muscle (SM) actin, which is associated with cell motility, was also examined. Using cultured tendon cells, migration was evaluated by counting the number of initial outgrowths from the tendon explants and by transwell filter migration assay. The distribution and assembly of alpha-SM actin were assessed by immunocytochemistry. The mRNA and protein expressions of alpha-SM actin were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Dose-dependent dexamethasone inhibition was demonstrated for both tendon cells outgrowth from the explants, ex vivo, and migration of tendon cells through the transwell filter, in vitro. Immunocytochemical staining revealed significant decreases in both the amount and assembly of alpha-SM actin in cells. Suppression of mRNA expression and protein level of alpha-SM actin was revealed from RT-PCR and Western blot analyses. In conclusion, dexamethasone inhibits tendon cell migration that is correlated with decreased gene expression of alpha-SM actin.

Achilles Tendon↗

PubMed2003

Postural control during sit-to stand and gait in stroke patients.

OBJECTIVE: To investigate the relationship of sit-to-stand and gait performance in hemiplegic stroke patients. DESIGN: A total of 40 chronic stroke patients with hemiplegia and 22 age-matched healthy subjects were included in this study. Data of a motion analysis system and three force platforms were collected in a rehabilitation unit of a medical center. RESULTS: Laboratory sit-to-stand measurement and gait analysis were evaluated in both groups via three AMTI (Advanced Mechanical Technology Inc.) force platforms and a Vicon 370 system (six high-resolution cameras and one AMTI force plate), respectively. The sit-to-stand and gait parameters of hemiplegic patients were correlated significantly, especially in rising speed and the maximal vertical force of both legs during rising. CONCLUSIONS: Hemiplegic stroke patients, who could stand up within 4.5 sec or who had a maximal vertical force difference of less than 30% of body weight between both legs, had better gait performance than the others did.

Activities of Daily Living↗

PubMed2002

Visual spatial attention in children with attention deficit hyperactivity disorder.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) was characterized by deficit in the attention mechanism. Until now, the visual-spatial attention deficit in children with ADHD remains controversial. We report a study of the visual spatial attention to assess covert shifts of attention and sustained attention theoretically linked to two neuroanatomically defined attentional system in the posterior and anterior parts of the human brain. METHODS: Using the Neuroscan system, the reaction time (RT) was measured according to three different within-subject conditions including cueing (valid, invalid and neutral); delay (800 msec and 100 msec); side [right visual field (RVF) and left visual field (LVF)] as well as one between-subject condition (healthy, ADHD). RESULTS: The AHDH group showed slower RTs overall (RT = 760 msec) than the comparison group (RT = 650 msec) (p = 0.001). RTs in the delayed condition of 800 msec (RT = 680 msec) were faster than in the delayed condition of 100 msec (RT = 730 msec) in all children (p < 0.001). The ADHD group showed significant lateral differences in RT (RTRVF: 880 msec > RTLVF: 830 msec) in the 100 msec delay for the invalid cueing condition (p = 0.045) that was not found in the comparison group. CONCLUSION: General dysfunction including posterior-based covert shift of attention and anterior-based sustained attention was found in ADHD group. Furthermore, asymmetric left parietal dysfunction in the disengaged operation was noted in those with ADHD.

Attention↗

PubMed2002

Decreased expression of proliferating cell nuclear antigen is associated with dexamethasone inhibition of the proliferation of rat tendon fibroblasts.

OBJECTIVE: To investigate the effects of dexamethasone (Dex) on the proliferation of cultured rat Achilles tendon fibroblasts at concentrations typically used for local injection treatment. METHODS: Fibroblasts cultured from rat Achilles tendons were treated with Dex at concentrations of 0, 10-4, 3 10-4, and 10-3 M. [3H]thymidine incorporation was used to measure the rate of cell proliferation. mRNA expression of proliferating cell nuclear antigen (PCNA) and cyclin kinase inhibitor p21CIP1 was determined by reverse transcription-polymerase chain reaction (RT-PCR). The protein levels of PCNA and p21CIP1 were investigated by Western blot analysis. RESULTS: An initial inhibitory effect on tendon fibroblast proliferation was observed at a concentration of 10-4 M. Further, a significant decline in [3H]thymidine incorporation as a function of Dex concentration was noted (p = 0.019). RT-PCR results revealed that PCNA mRNA expression was inhibited after Dex treatment. Western blot analysis of PCNA protein also revealed Dex downregulation. Gradual declines in the levels of PCNA mRNA expression and PCNA protein as a function of Dex concentration were noted. The expression of p21CIP1 both at mRNA and the protein levels remained constant. CONCLUSION: These results suggest that Dex inhibition of the proliferation of rat tendon fibroblasts is associated with a p21CIP1 independent decrease of the PCNA gene expression.

Achilles Tendon↗