Biomedical subjects

Chao Yang

Publications and source records attributed to Chao Yang.

At least 37 records · Page 2Linked to original sources

PubMed2005

Assessment of non-invasive intervertebral motion measurements in the lumbar spine.

This study compared the accuracy of new, FDA-approved, image-analysis software to conventional radiographic assessment techniques for the measurement of intervertebral motion. Six adult human cadaveric lumbar spines (L1-S1) were individually mounted in a custom Plexiglas device and electromagnetic sensors were rigidly mounted to the spinous processes of L3, L4, and L5. Lateral radiographs of the spines in neutral, full flexion, and full extension were digitized and analyzed both using the software and manually by three orthopedic surgeons. Compared to intervertebral rotations determined from the electromagnetic device, the errors in rotations reported by the software and surgeons were 0.47+/-0.24 degrees and 2.16+/-0.78 degrees , respectively. Rotations measured by the surgeons were significantly less accurate and more variable than that of the software (p<0.05).

Cadaver↗

PubMed2005

Total and intrasynovial work of flexion of human cadaver flexor digitorum profundus tendons after modified Kessler and MGH repair techniques.

PURPOSE: The purpose of this study was to compare directly the total work of flexion (TWOF) and the intrasynovial work of flexion (IWOF) of human flexor digitorum profundus tendons and to analyze the ratio of the IWOF to the TWOF of human flexor digitorum profundus tendons. These factors may be important clinically in understanding the role of different methods of postoperative tendon rehabilitation for different types of tendon repairs, especially at the early stage after tendon repair. METHODS: Two different tendon repairs, the modified Kessler and the Massachusetts General Hospital, were used in 18 digits from 6 freshly frozen human cadaver hands. The TWOF and the IWOF were tested by using a digit-resistance testing device. RESULTS: After tendon repair the TWOF increased 11.2% and 26.9% for the modified Kessler and MGH groups, respectively. The differences in increase between the 2 groups were significant. The IWOF increased 126.8% and 308.8% for the modified Kessler and Massachusetts General Hospital groups, respectively. The IWOF accounted for 16.4% of the TWOF for the intact tendon; this percentage was 28.6% and 45.0% for the modified Kessler and Massachusetts General Hospital groups, respectively. CONCLUSIONS: The IWOF accounts for 16% of the TWOF of normal human cadaver digits but it accounts for a much higher fraction after tendon repair. The ratio of the work of flexion within the synovial sheath to the TWOF varies depending on the type of repair chosen.

Aged↗

PubMed2005

Unified 3-D structure and projection orientation refinement using quasi-Newton algorithm.

We describe an algorithm for simultaneous refinement of a three-dimensional (3-D) density map and of the orientation parameters of two-dimensional (2-D) projections that are used to reconstruct this map. The application is in electron microscopy, where the 3-D structure of a protein has to be determined from a set of 2-D projections collected at random but initially unknown angles. The design of the algorithm is based on the assumption that initial low resolution approximation of the density map and reasonable guesses for orientation parameters are available. Thus, the algorithm is applicable in final stages of the structure refinement, when the quality of the results is of main concern. We define the objective function to be minimized in real space and solve the resulting nonlinear optimization problem using a Quasi-Newton algorithm. We calculate analytical derivatives with respect to density distribution and the finite difference approximations of derivatives with respect to orientation parameters. We demonstrate that calculation of derivatives is robust with respect to noise in the data. This is due to the fact that noise is annihilated by the back-projection operations. Our algorithm is distinguished from other orientation refinement methods (i) by the simultaneous update of the density map and orientation parameters resulting in a highly efficient computational scheme and (ii) by the high quality of the results produced by a direct minimization of the discrepancy between the 2-D data and the projected views of the reconstructed 3-D structure. We demonstrate the speed and accuracy of our method by using simulated data.

Algorithms↗

PubMed2005

[Allelopathy of Pseudomonas fluorescens: a preliminary study].

The study on the allelopathy of Pseudomonas fluorescens showed that 200 times dilution of its cultured solution could restrain the growth of all test crops, 400 times dilution showed a weak restraining effect on most crops, while 600 times dilution had some stimulating effect. The effects differed with crop varieties.

Crops, Agricultural↗

PubMed2005

[Study on the intercellular molecule-1 polymorphisms in an Chinese population with myocardial infarction].

OBJECTIVE: To investigate the association between intercellular adhesion molecule-1 (ICAM-1) gene + 12959G/A and + 13848A/G polymorphism and myocardial infarction (MI). METHODS: Polymerase chain reaction-sequence specific primers (PCR-SSP) technology and PCR-restriction fragment length polymorphism(PCR-RFLP) were used for the detection of ICAM-1 genotypes in 165 patients with MI(including acute MI and old MI) and 199 healthy controls. Plasma lipid levels and hyper sensitive C reactive protein (quantitive ELISA method was used) levels were measured in all subjects. RESULTS: + 12959G/A polymorphism was not detected in our study. The frequencies of AA,AG and GG Genotypes of + 13848A/G were 58.2% and 45.7%, 37.0% among patients and 45.2%, 4.8% and 9.0% among controls,respectively. There were statistically significant differences in the distributions of the genotype frequencies (P<0.05) between two groups, and the relative risk suffered from MI of AA genotype was 1.651 times of the GG and GA genotype (OR = 1.651, 95% CI: 1.089-2.504). CONCLUSION: There was no + 12959G/A polymorphism found in Chinese people. The coding single nucleotide polymorphism + 13848 A/G in the exon 6 of ICAM-1 gene was associated to MI and the allele A might serve as a risk factor for MI in Chinese.

Asian People↗

PubMed2004

Efficient Agrobacterium tumefaciens-mediated transformation of soybeans using an embryonic tip regeneration system.

Here, we report the establishment of an efficient, in vitro, shoot organogenesis, regeneration system for soybeans [Glycine max (L.) Merr.]. Mature soybean seeds were soaked for 24 h, the embryonic tips were collected and cultured on MSB5 medium supplemented with 3.5 mg l(-1) N6-benzylaminopurine (BAP) for 24 h, and explants were transferred to MSB5 medium supplemented with 0.2 mg l(-1) BAP and 0.2 mg l(-1) indolebutyric acid. Use of embryonic tips yielded a higher regeneration frequency (87.7%) than regeneration systems using cotyledonary nodes (40.3%) and hypocotyl segments (56.4%) as starting materials. Regenerated embryonic tips were inoculated with Agrobacterium tumefaciens strain EHA105, which contains the binary vector pCAMBIA2301, and cultured for 20 h. Our results showed that the T-DNA transfer efficiency reached up to 78.2% and the transformation efficiency reached up to 15.8%. These data indicate that the embryonic tip regeneration system can be used for efficient, effective Agrobacterium-mediated transformation.

Agrobacterium tumefaciens↗

PubMed2004

Tendon surface modification by chemically modified HA coating after flexor digitorum profundus tendon repair.

Carbodiimide derivatized HA (cd-HA) is less soluble in water than normal HA, and therefore has an increased tissue residence time. The purpose of this study was to study the effect of cd-HA gel on gliding and repair integrity during simulated repetitive motion of a repaired tendon in vitro. A total of 36 flexor digitorum profundus (FDP) tendons from six adult mongrel dogs were used and divided into three groups of control, simple HA, and cd-HA. The gliding resistance between the FDP and the proximal pulley, FDS, and bone was measured before laceration and after modified Kessler technique repair at 1, 5, 10, 50, 100, 200, 300, 400, and 500 cycles. After gliding testing, failure load, tendon stiffness, and resistance to gap formation were measured. The results showed from the first cycle to the 10th cycle, there were no significant differences in gliding resistance between the three testing groups (p > 0.05). From the 50th cycle onwards, the friction was significantly lower in the cd-HA gel group than in the control group (p < 0.05). Neither breaking strength, nor tendon stiffness, nor resistance to gap formation of the repairs were significantly different between the three groups (p > 0.05).

Coated Materials, Biocompatible↗

PubMed2004

Gliding characteristics and gap formation for locking and grasping tendon repairs: a biomechanical study in a human cadaver model.

PURPOSE: The purpose of this study was to compare the frictional characteristics and mechanical properties of various locking and grasping suture techniques in a human in vitro model of flexor tendon repair. METHODS: Forty-five cadaveric human flexor digitorum profundus tendons were transected in zone II and repaired using 1 of 5 core suture methods (n = 9 per group): either grasping (modified grasping Kessler, modified Lee) or locking (Pennington, modified Pennington, locking Lee) loop suture techniques. All repairs used 4-0 Supramid looped core suture and an epitenon running suture of 6-0 nylon. Gliding resistance at the tendon-pulley interface was measured along with failure strength and gap formation. The force to produce 0.5-, 1.0-, 1.5-, and 2.0-mm gaps were measured. RESULTS: One of the locking repairs, the locking Lee, had a gliding resistance significantly higher than that of one of the grasping repairs (modified grasping Kessler) and the other 2 locking repairs (Pennington, modified Pennington) (p <.05). There was no significant difference between the other grasping (modified Kessler, modified Lee) and locking (Pennington, modified Pennington) suture configurations (p =.21). The maximum force of one of the locking repairs, the modified Pennington repair (48.0 N; standard deviation, 3.9) was significantly higher than the other locking and grasping repairs (p <.05). The force required to produce more than 1.5 mm of gap for the modified Pennington repair was also significantly higher than that for some of the other grasping (modified Kessler, modified Lee) and locking (Pennington) repairs (p <.05). CONCLUSIONS: The lack of significant difference in gliding resistance among the similarly designed modified grasping Kessler, Pennington, and modified Pennington repairs (overall mean, 0.87 N; standard deviation, 0.16) suggests that the locking loop configuration itself does not adversely affect tendon gliding resistance. The modified Pennington repair increased not only ultimate strength but also resistance to gap formation more than 1.5 mm.

Aged↗

PubMed2004

Reducing friction by chemically modifying the surface of extrasynovial tendon grafts.

In this study we evaluated methods to reduce the friction of an extrasynovial tendon under a pulley in vitro. The surface of canine peroneus longus (PL) tendons was modified with gelatin and/or hyaluronic acid (HA) under different conditions. The gliding resistance between treated or control tendons and the canine digital flexor pulley was measured during 500 cycles of simulated flexion/extension. After 500 cycles, the gliding resistance of normal PL tendon increased 10-fold (p<0.05), while the gliding resistance of tendons coated with carbodiimide derivatized gelatin (cd-gelatin) or carbodiimide derivatized gelatin/HA (cd-gelatin-HA) did not increase significantly. The PL tendon treated with cd-gelatin-HA had a similar friction response during the repetitive motion as the intrasynovial flexor digitorum profundus (FDP) tendon. Scanning electron microscopy after 500 cycles of motion showed that the tendon surface in the group treated with cd-gelatin-HA appeared smoother than tendons in the other groups.

Animals↗

PubMed2004

Influence of the image quality deterioration of a tilted thick specimen on electron tomography.

In electron tomography (ET) based on a transmission electron microscope, the effective thickness of a specimen increases with the tilt angle and, therefore, the projection quality may deteriorate because of electron scattering. The information-missing region, however, can be reduced by broadening the specimen tilt range. To clarify the general influence of these effects on ET, the projection quality varying with the tilt angle was quantitatively evaluated for a 5-microm thick specimen observed with a 3 MV ultrahigh-voltage electron microscope. Simulations of three-dimensional reconstruction were then performed for different specimen thicknesses and tilt ranges. As a result, the ET accuracy was shown to decrease as the specimen thickness increased. However, an optimum specimen-tilt range, at which ET could reach its highest accuracy, was found to exist and become small with the increase of the specimen thickness. The presented results are helpful for determining the specimen thickness limitation on the ET resolution and improving the ET fidelity of thick specimens.

Computer Simulation↗

PubMed2004

[Distribution features of HLA-DRB1 allele frequencies in normal cord blood donors of 3 438 Shandong Hans].

The objective of the study was to research the distribution features of HLA-DRB1 alleles in Shandong Hans' population and explore the possibility of finding the cord blood donor of HLA-DR matched to perform the stem cell transplantation for more patients from larger region of China and even other areas in the world. The subjects of the study were drawn from 3 438 Shandong Hans donors in Shandong Umbilical Cord Blood Bank and were tested by PCR-SSP technique for HLA-DR low resolution typing. The result indicated that the most prevalent five alleles of HLA-DRB1 locus were DRB1 * 15 (0.1817), * 07 (0.1369), * 09 (0.1221), * 04 (0.1084) and * 12 (0.1038). The DR18 has the lowest gene frequency 0.0003, while DRB1 * 10, * 16 and * 01 showed lower gene frequencies (GF), which GF were 0.0151, 0.0262, and 0.0322 respectively. As compared the HLA-DRB1 GF of Shandong Hans with those of other Han Chinese and other ethnic populations, there were unique distributed features of DRB1 alleles among various races populations, and those among the studied population groups from various regions with the same race origin. The difference from various regions in the same race was less than that among different races. In conclusion, a patient of Han Chinese is easier to search a DR-matched cord blood donor in Shandong Umbilical Cord Blood Bank, especially from northern Hans. No DRB1 allele is unique to single racial group and majority of DRB1 low-resolution phenotypes are common to all studied groups. It is reasonable for some patients from other races including Caucasian and Japanese to receive a transplant of cord blood stem cell matched with HLA-DR in Shandong Umbilical Cord Blood Bank.

Asian People↗

PubMed2004

[Utilization of powdered peanut hull as biosorbent for removal of anionic dyes from aqueous solution].

An untried, low cost, locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated. Powder prepared from peanut hull had been used for biosorption of three anionic dyes, amaranth (Am), sunset yellow (SY) and fast green FCF (FG). The effects of various experimental parameters (e.g. initial pH and dye concentration, sorbent dosage, particle size, ion strength, contact time etc.) were examined and optimal experimental conditions were decided. At initial pH 2.0, three dyes studied could be removed effectively. When the dye concentration was 50 mg x L(-1), the percentages of dyes sorbed was 95.5% in Am, 91.3% in SY and 94.98% in FG, respectively. The ratios of dyes sorbed had neared maximum values in all three dyes when sorbent dose of 5.0 g x L(-1) and the sorbent particle size in 80-100 mesh was used. The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes. The equilibrium values arrived at about 36 hour for all three dyes. The isothermal data of biosorption followed the Langmuir and Freundlich models. The biosorption processes conformed the pseudo-first-order rate kinetics. The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.

Adsorption↗

PubMed2003

Biocompatibility of a physiological pressure sensor.

A newly developed fiber optic micropressure sensor was evaluated for biocompatibility using the International Organization for Standardization (ISO) test standard 10993-6. The test material and an inert control (fused silica glass) were tested in New Zealand white rabbits. Four test specimens were implanted in the paravertebral muscles on one side of the spine about 2-5 cm from the mid-line and parallel to the spinal column. Similarly, four control specimens were implanted on the opposite side. The implantation periods were 1, 4, and 12 weeks to ensure a steady state biological tissue response. Four animals were tested at each time period. Macroscopic and microscopic observations were performed to compare the biological reactions between the test and control materials. There was an inflammatory reaction at 1 week which subsided at 4 weeks. There was fibrous tissue growth near the implant that also decreased over time. Most importantly, there was no significant difference in the biological response between the test and control materials. Therefore, we conclude that the pressure microsensor is biocompatible.

Animals↗

PubMed2003

Xanthanolides, germacranolides, and other constituents from Carpesium longifolium.

Three new xanthanolides, 1-3, along with nine known compounds, were isolated from the aerial parts of Carpesium longifolium. The structures of the new compounds were elucidated as 1beta,4beta-epoxy-5beta-hydroxy-10alphaH-xantha-11(13)-en-12,8beta-olide (1), 1beta,4beta,4alpha,5beta-diepoxy-10alphaH,11alphaH-xantha-12,8beta-olide (2), and 4-acetoxy-1beta,5beta-epoxy-10alphaH-xantha-11(13)-en-12,8beta-olide (3) by spectroscopic methods including IR, EIMS, HRESIMS, and 1D and 2D NMR experiments. Parthenolide and michelenolide exhibited significant cytotoxic activity against cultured SMMC-7721 (human hepatoma) and HO-8910 (human ovarian carcinoma) cells.

Antineoplastic Agents, Phytogenic↗

PubMed2003

Sesquiterpenes and other constituents from the aerial parts of Inula japonica.

Three new sesquiterpenes, 1beta-hydroxy-8beta-acetoxycostic acid methyl ester, 1beta-hydroxy-8beta-acetoxyisocostic acid methyl ester and 1beta-hydroxy-4alpha,11alpha-eudesma-5-en-12,8beta-olide, along with fourteen known compounds were isolated from the aerial parts of Inula japonica. The structures of these new compounds were elucidated by spectroscopic methods (IR, EIMS, HRMS, 1D and 2D NMR). 1,6alpha-dihydroxy-4alphaH-1,10-secoeudesma-5(10),11(13)-dien-12,8beta-olide exhibited appreciable cytotoxic activity against cultured SMMC-7721 (human hepatoma cell) and HO-8910 (human ovarian carcinoma cell) with IC 50 values of 52.22 and 21.32 microg/mL, while 5alphaH-eudesma-4(15),11(13)-dien-12,8beta-olide showed remarkable cytotoxic activity against cultured SMMC-7721 and HO-8910 with IC 50 values of 6.21 and 5.28 microg/mL, respectively.

Antineoplastic Agents, Phytogenic↗

PubMed2003

[Ecological distribution of macrofungi in Qingliang Mountain Natural Reserve, Anhui Province].

The north side of Qingliang Mountain Natural Reserveis is very rich of macrofungi resources. There are 160 species, belonging to 72 genera, 38 families, 10 orders and 2 classes, and distributing in the evergreen broadleaf forest, Pinus massoniana forest, evergreen-decidous mixed broadleaf forest, and Pinus taiwanensis forest. According to their economic value, these macrofungi may be grouped into two types: edible (72 species) and medicinal (55 species); and according their ecological habitat, they may be grouped into lignicolous (68 species), entomophilous (84 species), and ectomycorrhizal (21 species). Our study showed a certain regularity of their distribution, i.e., it varied with the ecological conditions of forests, tree species, soil types and altitude. Many economical macrofungi in this region could serve as one of the important natural resources, and had great potential usage on the edibility, medicinal and forestation.

Conservation of Natural Resources↗

PubMed2002

Sesquiterpene lactone glycosides, eudesmanolides, and other constituents from Carpesium macrocephalum.

Two new sesquiterpene lactone glycosides and two new eudesmanolides, along with twelve known compounds were isolated from seeds of Carpesium macrocephalum. The structures of these new compounds were elucidated as 2alpha- O-beta- D-glucopyranosyl-5alpha, 11alpha H-eudesma-4(15)-en-12,8beta-olide ( 1), 2alpha- O-beta- D-glucopyranosyl-5alpha H-eudesma-4(15),11(13)-dien-12,8beta-olide ( 2), 2alpha-acetoxy-5alpha-hydroxy-11alpha H-eudesma-4(15)-en-12,8beta-olide ( 3) and 2alpha,5alpha-dihydroxy-11alphaH-eudesma-4(15)-en-12,8beta-olide ( 4) by spectroscopic methods including 2D NMR techniques ( (1)H- (1)H COSY, (1)H- (1)H NOESY, HMQC, HMBC) and chemical transformations. Compounds 1, 6, 8, 9 and 10 exhibited moderate antibacterial activity, while compound 4 showed appreciable cytotoxic activity against cultured SMMC-7721 (human hepatoma cell).

Anti-Bacterial Agents↗

PubMed2002

Clinical practice of video-assisted thoracoscopic surgery in children.

OBJECTIVE To estimate the value of video-assisted thoracoscopic surgery (VATS) in diagnosis and treatment of children with chest diseases. METHODS From May 1997 to October 2001, forty-one children (25 boys and 16 girls) with chest diseases received VATS under general anesthesia in our hospital. Their average age was 6.9 years (range 9 days to 16 years) and their median body weight was 22.5 kg (2.8-54.0 kg). Operative procedures included fibrinopurulent empyema with debridement and decortication in 15 children, biopsy and(or) resection of mediastinal tumor in 11, bullectomy and cystectomy of the lung in 6, lobectomy with huge cyst of the lung or sequestration in 5, clearance of hemothorax in 2, and exploration, and repair of diaphragmatic hernia in 2. RESULTS The mean operative time was 74 minutes (range 30 to 220 minutes). The lost blood volume was 33 ml (range 10 to 150 ml). The mean duration of chest drainage and hospital stay after surgery was 2.4 days and 7.0 days (range 4 to 15 days) respectively. One infant born after 9 days with congenital diaphragmatocele died of respiratory failure due to left pulmonary hypoplasia 10 days after operation. Postoperative morbidity was 7.3% (3 patients). Forty patients were followed up for an average of 15.6 months, 38 patients lived and developed normally, and 2 received chemotherapy. CONCLUSION Video-assisted thoracoscopy is a safe and effective diagnostic and therapeutic procedure for children with chest disease, and this approach has an important place in pediatric thoracic surgery.

Adolescent↗