Biomedical subjects

Zhu Lin

Publications and source records attributed to Zhu Lin.

8 recordsLinked to original sources

PubMed2006

Cyclic stretch translocates the alpha2-subunit of the Na pump to plasma membrane in skeletal muscle cells in vitro.

The Na+-K+-ATPase and its regulation is important for maintaining membrane potential and transmembrane Na(+) gradient in all skeletal muscle cells and thus is essential for cell survival and function. In our previous study, cyclic stretch activated the Na pump in cultured skeletal muscle cells. Presently, we investigated whether this stimulation was the result of translocation of Na+-K+-ATPase from endosomes to the plasma membrane, and also evaluated the role of phosphatidylinositol 3-kinase (PI 3-kinase), the activation of which initiated vesicular trafficking and targeting of proteins to specific cell compartments. Skeletal muscle cells were stretched at 25% elongation continuous for 24h using the Flexercell Strain Unit. The plasma membrane and endosome fractions were isolated and Western blotted to localize the Na+-K+-ATPase alpha1- and alpha2-subunit protein. The results showed stretch increased Na+-K+-ATPase alpha1- and alpha2-subunit protein expression in plasma membrane fractions and decreased it in endosomes. The alpha2-subunit had a more dynamic response to mechanical stretch. PI 3-kinase inhibitors (LY294002) blocked the stretch-induced translocation of the Na+-K+-ATPase alpha2-subunit, while LY294002 had no effect on the transfer of alpha1-subunit. We concluded that cyclic stretch mainly stimulated the translocation of the alpha2-subunit of Na+-K+-ATPase from endosomes to the plasma membrane via a PI 3-kinase-dependent mechanism in cultured skeletal muscle cells in vitro, which in turn increased the activity of the Na pump.

Animals↗

PubMed2006

Effects of different magnitudes of mechanical strain on Osteoblasts in vitro.

In addition to systemic and local factors, mechanical strain plays a crucial role in bone remodeling during growth, development, and fracture healing, and especially in orthodontic tooth movement. Although many papers have been published on the effects of mechanical stress on osteoblasts or osteoblastic cells, little is known about the effects of different magnitudes of mechanical strain on such cells. In the present study, we investigated how different magnitudes of cyclic tensile strain affected osteoblasts. MC3T3-E1 osteoblastic cells were subjected to 0%, 6%, 12% or 18% elongation for 24h using a Flexercell Strain Unit, and then the mRNA and protein expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) were examined. The results showed that cyclic tensile strain induced a magnitude-dependent increase (0%, 6%, 12%, and 18%) in OPG synthesis and a concomitant decrease in RANKL mRNA expression and sRANKL release from the osteoblasts. Furthermore, the induction of OPG mRNA expression by stretching was inhibited by indomethacin or genistein, and the stretch-induced reduction of RANKL mRNA was inhibited by PD098059. These results indicate that different magnitudes of cyclic tensile strain influence the biological behavior of osteoblasts, which profoundly affects bone remodeling.

Animals↗

PubMed2006

[Effects of wrist-ankle acupuncture on functional states of the vegetative nerve in the recruit].

OBJECTIVE: To observe effects of wrist-ankle acupuncture on functional states of the vegetative nerve in the recruit. METHODS: Sixty recruits with the vegetative nerve balance index y > +0.56 determined with "Wenger-Chong Zhong Zhong Xiong"'s vegetative nerve balance factor assay were randomly divided into a treatment group and a control group. The treatment group were treated with wrist-ankle acupuncture and the control group with nothing. RESULTS: After treatment, 24 cases with y < +0.56 was found in the treatment group and 16 cases in the control group with a significant difference between the two groups (P < 0.05). CONCLUSION: Wrist-ankle acupuncture can better improve functional state of the vegetative nerve in the recruit.

Acupuncture Therapy↗

PubMed2004

Separation and identification of 20 chemical constituents in the traditional Chinese medicinal preparation Shenbao tablet by LC-ESI-MS3.

A sensitive and specific high-performance liquid chromatography (HPLC)-electrospray ionization multiple-stage mass spectrometry for the simultaneous separation and identification of 20 chemical constituents in the traditional Chinese medicinal preparation of the Shenbao tablet is established. The samples are separated with an Alltima C(18) column (250 x 4.6 mm, 5 microm) by linear gradient elution using water-acetic acid (A; 100:0.5, v/v) and acetonitrile (B; 0 min, 76:24; 15 min, 70:30; 40 min, 53:47; 50 min, 30:70; and maintain 10 min) as the mobile phase at a flow rate of 1.0 mL/min. The ion trap mass spectrometer is coupled to the HPLC system. Satisfactory results are obtained within 60 min for the simultaneous separation and identification of the 20 constituents. This is the first report on the analysis of main chemical constituents in the Shenbao tablet.

Chromatography, High Pressure Liquid↗

PubMed2004

[Cloning genes sensitive to mechanical stretch in osteoblasts through subtractive hybridization technique].

OBJECTIVE: In this experiment, genes sensitive to mechanical stretch in osteoblast like cells were cloned through subtractive hybridization technique. METHODS: Two dimensional mechanical stretch with deformation of 12% and frequency of 6 cycles was loaded on human osteoblastic like cell line Saos-2. Complementary deoxyribonucleic acid (cDNA) library of cells was constructed 12 h after loading, acting as tester. cDNA library of cells without loading was constructed, acting as driver. A subtractive cDNA library osteoblastic like cell stimulated with mechanical stretch was constructed through subtractive hybridization technique. RESULTS: Of clones randomly selected from this library, fifteen genes were identified to be the differentially expressed genes. Comparing with the sequences published in GeneBank via Internet, two sequences located in chromosome 9 and 18 respectively were identified to be novel, which were named as stretch sensitive gene 1 and stretch sensitive gene 2. CONCLUSION: It is an efficient approach to clone and study genes relative to mechanical stretch through subtractive hybridization technique.

Cell Line↗

PubMed2003

[Effect of different tension stress on collagen synthesis in human periodontal ligaments fibroblasts in vitro].

OBJECTIVE: To observe the change in amount of collagen synthesis under different tension stress patterns in vitro. METHODS: Human periodontal ligament fibroblasts (HPDLF) were harvested and subjected to the cellular mechanical research system for the detection of collagen synthesis under static and dynamic tension stress in different frequency and magnitude with 3H-Proline for 16 h, 24 h and 32 h. RESULTS: Dynamic tension stress group 2(5 kPa-2.5 kPa-5 kPa) could most obviously increase collagen synthesis in HPDLF, and then control group (0 kPa), static tension stress group (5 kPa) and dynamic tension stress group 1(5 kPa-0 kPa-5 kPa) came next in order. CONCLUSION: Tension stress pattern can affect collagen synthesis in HPDLF. Appropriate dynamic tension stress can increase the amount of collagen synthesis in HPDLF.

Collagen↗

PubMed2003

[Effect of different tension stress on the proliferation activity of human periodontal ligament fibroblast in vitro].

OBJECTIVE: The aim of this study was examine the proliferation activity of human periodontal ligament fibroblasts (HPDLF) under different tension stress in vitro so as to learn the stress-biological effect and growth regularity in orthodontic treatment of HPDLF. METHODS: HPDLF were harvested and subjected to the cellular mechanical research system, and the levels of proliferation activity under static and dynamic tension stress in different frequency and magnitude were detected by use of 3H-TdR at 16 h, 24 h and 32 h. RESULTS: It was found that the proliferation activity of HPDLF obviously increased in the static tension stress group (5 kPa), whereas the proliferation activity of HPDLF appeared to decrease in the dynamic tension stress groups (5 kPa-2.5 kPa-5 kPa; 5 kPa-0-5 kPa). CONCLUSION: Different tension stress patterns have different effects on the proliferation of HPDLF. Static tension stress can obviously enhance the proliferation of HPDLF.

Cell Division↗

PubMed2002

Study on the correlation between tongue size and openbite.

OBJECTIVE: To investigate the correlation between tongue size and openbite. METHODS: The tongue size of the openbite patients and the subjects with normal occlusion was measured by B-type ultrasonic imaging respectively. The tongue size of the openbite patients and the subjects with normal occlusion was compared. RESULTS: The tongue size in openbite group was larger than in normal occlusion group. The difference was statistically significant. CONCLUSIONS: Tongue size was related to the openbite.

Adolescent↗