In this article, the position of nanotechnology and its effects on life science are concisely discussed, including the effects of nanotechnology on biology, on the study of new type biomaterials, on the development of new drugs, on diagnosis and therapy methods. The importance of nanotechnology in life science is summarized, and the application and development of nanotechnology in life science are also discussed.
Biocompatible Materials ; Biological Science Disciplines ; Drug Design ; Humans ; Nanotechnology

Bone tumor metastases is relatively common. Approximately 5%-20% of spinal metastatic tumors will finally invade the spinal cord and exacerbate symptoms. The adoption of combined approach in recent years has significantly increased the survival rate. After excision of the tumors, internal fixation instrumentations are needed to stabilize the vertebrae. These procedures must be performed under the condition that the patients can tolerate the operation. Fused vertebra with instrumentation may cause degenerative diseases at the adjacent segments, which has been a problem of concern recently. Results of biomechanical tests indicated that these degenerative changes are related to the increased motion range of the neighboring segments. An old view is "the more rigid the instrumentation is, the better the results are", which has been disproved by clinical evidences. Improper use of internal spine fixation instrument should be avoided. Artificial intervertebral disc replacement can produce favorable short-time effects, however, its long-term effects and complications still requires further observations.
Humans ; Internal Fixators ; Intervertebral Disc ; surgery ; Spinal Fusion ; adverse effects ; methods ; Spinal Neoplasms ; secondary ; surgery ; Spine ; surgery

Osteonecrosis is a common disease, mainly affecting femoral head. Good animal models are helpful in research on the pathologic mechanism of osteonecrosis and the exploration of effective treatment. Although it is relatively easy to establish animal models of early osteonecrosis of femoral head using various approaches, it is difficult to develop an animal model that mimics the full range of osteonecrosis of femoral head. In this paper, we reviewed the current researches on experimental animal models of osteonecrosis, with an attempt to provide evidences for choosing the appropriate animal models and find the way of future development.
Animals ; Disease Models, Animal ; Osteonecrosis

ObjectiveTo explore the Apolipoprotein-E （ApoE） gene polymorphism in patients with Alzheimer's disease （AD）, vascular dementia (VD) or mild cognitive impairment (MCI). MethodsPeripheral blood was taken from patient with AD, VD or MCI to determine the ApoE genotypes. ResultsThe most of the patients were ε3/ε3 genotype, while the ε2/ε2 and ε4/ε4 could not be detected. ε3/ε4 genotype （P=0.001） and ApoE ε4 allele （P=0.013） was more frequent in AD than in MCI. ApoE ε4 was more frequent in VD than in MCI （P=0.044）. ConclusionApoE ε4 allele is a risk factor in AD, and may be associated with VD and MCI.

OBJECTIVETo observe the effect and mechanism of zoledronate on prevention of collapse in an animal model of osteonecrosis.

METHODSIschemic osteonecrosis was surgically induced in 16 SD rats (which were further divided into zoledronate group and placebo group); another 8 rats were used as sham surgery group (n=8). The animals were killed 5 weeks after surgery. Radiographic, Micro-CT, histological, and immunohistochemical assessments were performed.

RESULTSRadiographic assessment showed better preservation of the femoral head shape in the zoledronate group than in the placebo group but not significantly different from the sham surgery group. Micro-CT assessment showed higher total volume, bone volume, and total mineralized content in the zoledronate group(all P0.05). Compared with the placebo group, the zoledronate group had reduced osteoclast and osteoblast activity, as confirmed by histological examinations.

CONCLUSIONZoledronate can decrease the femoral head deformity by reducing the osteoclast activity while suppressing new bone and vessels formation in a rat model of traumatic osteonecrosis, and therefore may delay the collapse of femoral head.

Animals ; Diphosphonates ; therapeutic use ; Disease Models, Animal ; Femur Head ; drug effects ; pathology ; Femur Head Necrosis ; drug therapy ; pathology ; Imidazoles ; therapeutic use ; Male ; Osteoblasts ; drug effects ; pathology ; Osteoclasts ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo compare the angiogenesis in unstable and stable plaques and to investigate the potential role of neovessels in creating vulnerable sites for atherosclerotic plaques.

METHODSSpecimens of coronary arteries were obtained from 52 autopsy cases with acute coronary syndromes. Plaque morphology was studied by use of stained slides. 922 tissue blocks of late-stage lesions were classified into two groups: (1) unstable plaque (n = 153), the plaque was characterized by a large extracellular lipid core (more than 40% of the plaque area); (2) stable plaque (n = 769), lipid core less than 40% of the plaque area. Forty blocks were selected randomly from each group and serial sections were stained immunohistochemically with a polyclonal antibody against F VIII RAg. Computer-aided planimeter was used for quantitative analysis.

RESULTSIn unstable plaques, the occurrence of neovessels was more frequent and the neovessel density (number/mm(2)) was significantly increased as compared to that of stable plaques (frequency: 80.4% vs 66.6%, P < 0.01; shoulder: 22.16 +/- 19.96 vs 10.04 +/- 11.52, base: 21.68 +/- 20.44 vs 9.68 +/- 11.52, fibrous cap: 3.80 +/- 5.32 vs 1.48 +/- 2.28, P < 0.05). Most neovessels were located in the shoulder region and at the base of plaques.

CONCLUSIONSThese findings suggest that neovessels in coronary atherosclerotic plaques are closely associated with the decreased stabilization of the plaques.

Aged ; Aged, 80 and over ; Coronary Artery Disease ; pathology ; Coronary Vessels ; pathology ; Female ; Humans ; Male ; Neovascularization, Pathologic ; pathology

OBJECTIVESTo analyze the relationship between oxidized low density lipoprotein (oxLDL), angiogenesis and stabilization of atherosclerotic plaques in human coronary arteries; and to investigate the role of oxLDL in creating vulnerable sites in atherosclerotic plaques.

METHODSSamples of coronary arteries were obtained at autopsies of 42 patients with acute coronary syndrome. Eighty randomly selected blocks were studied by immunohistochemistry using antibodies against oxLDL and endothelial cells (factor VIII). Computer-aided planimeter was used for quantitative analysis.

RESULTSIn unstable plaques, percentage of immunoreactive areas for oxLDL was significantly higher than that in stable plaques. Most of the oxLDL were located in shoulder region of these plaques, as compared to the fibrous cap and basal regions. The details of distribution of oxLDL were as follows: shoulder region (20.43 +/- 3.12 for unstable plaques and 17.65 +/- 4.22 for stable plaques), fibrous cap (4.77 +/- 2.03 for unstable plaque and 2.80 +/- 0.22 for stable plaques) and basal region (5.65 +/- 1.65 for unstable plaques and 3.22 +/- 1.02 for unstable plaques). OxLDL was also a main component in the lipid core. In the shoulder region, there was a significant positive correlation between neovascularization and oxLDL (r = 0.8247, P = 0.000).

CONCLUSIONSThe amount of oxLDL is significantly higher in unstable atherosclerotic plaques, especially over the shoulder region. OxLDL in coronary atherosclerotic plaques is thus an important factor in determining stabilization of the plaques. OxLDL may induce influx of inflammatory cells which subsequently leads to decreased plaque stabilization.

Angina, Unstable ; metabolism ; pathology ; Coronary Artery Disease ; metabolism ; pathology ; Humans ; Immunohistochemistry ; Lipoproteins, LDL ; metabolism ; Myocardial Infarction ; metabolism ; pathology ; Neovascularization, Pathologic ; metabolism ; pathology

OBJECTIVETo develop a procedure by which Schwann cells and myelin in the peripheral nerve could be removed while the basal lamina tubes remained intact, and to obtain a thick and long acellular nerve allograft in humans.

METHODSFour ulnar nerves 10.0 cm long and 4.0 - 5.0 mm in diameter were excised from a donated male body and cleaned from external debris. The nerves were treated with a solution of Triton X-100 and a solution of sodium deoxycholate at room temperature. After a final wash in water, the nerves were stored in phosphate-buffered saline (PBS, pH 7.2) at 4 degrees C. HE, luxol fast blue and fibrin staining were performed to visualize cells, myelin and basal membranes respectively and immunohistochemical staining was performed to visualize the presence of laminin, a Schwann cell lamina component, both in fresh and acellular nerve segments. To reveal overall structure better, methylene blue-fuchsin staining was performed in semithin section. The ultrastructure of acellular and fresh nerves were observed and photographed in a transmission electron microscope.

RESULTSThe acellular human ulnar nerve was white long cylinder with well elasticity and ductility. HE, myelin and fibrin staining revealed that cells, axons and myelin sheath were removed and basal membrane was preserved after extraction procedure. Staining for the presence of laminin showed that the Schwann cell basal lamina component were present in the nerves after chemical treatment. Methylene blue-fuchsin staining and transmission electron microscopy showed that the myelin sheaths were absent in the extracted nerve segments and empty basal lamina tubes remained in the endoneurium.

CONCLUSIONSWe developed an extracted procedure with the detergents of Triton X-100 and deoxycholate, by which cells, axons and myelin sheaths could be removed from a human ulnar nerve while the basal lamina tubes remain intact and a thick long acellular nerve allograft is obtained. The laminin, a Schwann cell basal lamina component, can be preserved in the acellular nerve.

Adult ; Axons ; drug effects ; Cell Separation ; methods ; Deoxycholic Acid ; pharmacology ; Humans ; Male ; Myelin Sheath ; drug effects ; Octoxynol ; pharmacology ; Transplantation, Homologous ; Ulnar Nerve ; cytology ; transplantation ; ultrastructure

OBJECTIVETo investigate modulatory role of Rac1 protein in epidermal stem cell (ESC) migration during wound healing, in order to provide a reference for enriching basic theory of wound healing and guiding clinical application.

METHODSConstitutively active mutant of Rac1 protein (Rac1Q61L) or dominant negative isoform of Rac1 protein (Rac1T17N) was transfected into ESC using a retroviral vector FUGW, and retroviral vector FUGW transfected into ESC in singles was used as blank control. The cells were divided into 3 parts according to the random number table and treated as follows. First, equal numbers of cells were inoculated into 24-well plates coated with collagen I (20 µg/mL), collagen IV (20 µg/mL) or fibronectin (10 µg/mL). Cells adhered to above matrices were quantitated using CytoTox 96 colorimetric kit. Second, 1000 cells adhered to collagen IV, after being stained with tetramethyl rhodamine isothiocyanate-phalloidin, were collected for observation of cell morphology and comparison of spreading area under confocal laser scanning microscope. Third, ESC with density of 2 × 10(5) cells per well were placed in upper compartment of Transwell chamber, DK-SFM culture medium alone or that containing stromal cell derived factor 1 (SDF-1) was added into lower compartment of Transwell chamber. Migration of ESC was observed using inverted phase contrast microscope, and the result was denoted as migration rate. Lastly, ESC with density of 7.5 × 10(5) cells per well was inoculated into 6-well plates for 12 hours, and treated with 4 µg/mL mitomycin C for 2 hours. The remaining scratch width of monolayer was respectively measured 6 hours or 12 hours after scratching to calculate the percentage of remaining scratch width. Data were processed with t test.

RESULTSCompared with that of blank control, the number of Rac1Q61L-transfected cells adhered to collagen I was significantly increased (t = 5.302,P < 0.05), while the number of Rac1T17N-transfected cells adhered to collagen I, IV, and fibronectin were all obviously decreased (with t value respectively 13.741, 15.676, 8.256, P values all below 0.05). Confocal laser scanning microscope showed that spreading area of Rac1Q61L-transfected ESC (with laminate pseudopodia on edge) and Rac1T17N-transfected ESC was respectively larger and smaller as compared with that of blank control. With SDF-1 effect, the migration rate of Rac1T17N-transfected ESC was decreased by 78.0% and Rac1Q61L-transfected ESC was increased by 43.4% as compared with that of blank control. Without SDF-1 effect, the migration rate of Rac1T17N-transfected ESC was decreased by 55.2%, while the migration rate of Rac1Q61L-transfected ESC was close to that of blank control. Six or 12 hours after scratching, the percentage of remaining scratch width in Rac1Q61L-transfected ESC was lower as compared with that in blank control [(39 ± 9)% vs. (43 ± 5)%, (6 ± 5)% vs. (18 ± 7)%, with t value respectively 1.027, 4.389, with P value respectively above and below 0.05], while that in Rac1T17N-transfected ESC [(81 ± 9)%, (71 ± 11)%, respectively] was obviously higher as compared with that in blank control (with t value respectively 11.386, 11.726, P values all below 0.05).

CONCLUSIONSRac1 protein may control the migration of ESC by regulating its adhesion, spreading, and chemotaxis, and it plays an active role in wound healing accelerated by ESC.

Cell Movement ; Cell Proliferation ; Epidermis ; cytology ; Epithelial Cells ; Humans ; Mutation ; Stem Cells ; cytology ; Transfection ; Wound Healing ; rac1 GTP-Binding Protein ; genetics ; metabolism

OBJECTIVETo evaluate application of the sponge of demineralized bone matrix (SDBM) in tissue engineering of bone.

METHODSSDBM was prepared from long bone of rabbits. Bone marrow cells were flushed from the bone shaft of femurs of a two-month-old New Zealand white rabbit. After the cells were cultured for 9 days, the flasks were added into dexamethasone (10(-8) mol/L), beta-glycerophosphate sodium (10 mmol/L) and L-ascorbic acid (50 micrograms/ml). After 5 weeks, the cultured cells were collected and marked by 5-Bromo-2'-dexyouridine (BrdU). The grand sum of cells seeded on a piece of SDBM was about (4-6) x 10(6). The composites of cells and SDBM (tissue engineered chip, TEC) were implanted into muscles and bone defects of radius in rabbits. A standard procedure was applied to make a 10 mm long defect bilaterally in the radius of nine skeletally mature male New Zealand white rabbits. All of the 18 defects were randomly divided into three groups: group I, six defects were grafted by TEC; group II, six defects were grafted with SDBM alone; group III, six defects were empty.

RESULTSThe results of radiographic and histological evaluation showed that all of the defects were repaired in group I and group II at 6 weeks, none of the defects was repaired in group III. The results of BrdU staining showed that the staining was positive in group I, but negative in group II. Biomechanical test showed that the compressive ultimate strength (CUS) of new bone in TEC implanted group was comparable with normal radius (P = 0.623) and in SDBM implanted group was significant lower than normal radius (P = 0.038).

CONCLUSIONSThe TEC can form cartilage and bone tissue in muscles and repair segmental bone defects. SDBM is a kind of effective natural scaffold in tissue engineering of bone.

Animals ; Bone Demineralization Technique ; Bone Marrow Cells ; cytology ; Bone Marrow Transplantation ; Bone Matrix ; Implants, Experimental ; Male ; Rabbits ; Radius Fractures ; surgery ; Random Allocation ; Stem Cells ; cytology ; Tissue Engineering