Biomedical subjects

G M Zhang

Publications and source records attributed to G M Zhang.

At least 19 recordsLinked to original sources

PubMed2004

Control of nutrients after discharge to lakes through wastewater.

Control of nutrients as nitrogen and phosphorus after discharge into lakes is necessary since it is difficult and costly to control within wastewater plants currently in China. This paper studied the cycling of phosphorus and nitrogen with water and sediments from two lakes in China. It is found that oxygen plays a critical role in regulating phosphorus and nitrogen cycling within water and sediments. Three different oxygenation methods including aeration, calcium peroxide and hydrogen peroxide were studied to control phosphorus and nitrogen in overlying water. In anoxic conditions, the P concentration in water increased from an average 14 microg/L to 115.2 microg/L for Xili Lake, and from an average 24 microg/L to 1,000 microg/L for Jinchun Lake. The concentration of ammonia increased under anoxic conditions, while the concentration of nitrate increased under oxic conditions. In anoxic conditions, the nitrate concentration decreased probably through denitrification. Both N and P accumulation processes can be controlled under the three treatments. The phosphorus removal efficiency from the water body was in the order of CaO2 addition > aeration > H2O2 addition, while controlling effectiveness for ammonia was in the order of aeration > CaO2 addition > H2O2 addition.

Ammonia↗

PubMed2003

Variation of microcystins in a lake for water supply.

A site investigation was conducted to correlate the relationships between microcystins (MC) concentration and algal growth in Dianchi Lake in China. Laboratory experiments were undertaken to test the effects of sediment adsorption, photoirradiation and biodegradation on microcystins removal. Bioaccumulation of microcystins was also determined using silver carp fish. It was observed that MC concentrations varied in accordance with algae growth in Dianchi Lake. The results obtained in the laboratory demonstrated that the removal of MC with fresh sediments was less than 10%, photoirradiation removed more than 75% MC within two hours, and the biodegradation needed much longer time to produce substantial degradation of MC. The results suggest that bioaccumulation of microcystins in fish was not significant in Dianchi Lake.

Animals↗

PubMed2003

Fluctuation of microcystins in water plant.

This study was undertaken to investigate the distribution and variation of microcystins (MC) from a water resource to a water plant in China including long distance transportation, ClO2 preoxidation, coagulation/precipitation, filtration, and disinfection. Advanced treatment methods including ozonation and granular activated carbon (GAC) adsorption were tested to remove microcystins from drinking water. The results indicated that, when containing high level of algae in raw water, preoxidation at 2 mg/L of ClO2 was not enough to stop algae growth in long distance transportation. In the water plant studied, both coagulation and filtration caused significant increase instead of removal of microcystins in drinking water. Chlorine disinfection removed part of microcystins. However, both ozonation and GAC adsorption were able to remove microcystins completely, thereby improving the quality of drinking water in terms of microcystins.

China↗

PubMed2002

Miniaturization of surface acoustic waves rotary motor.

This paper presents the experimental study of a miniaturized surface acoustic waves (SAWs) rotary motor and the theoretical calculation. After the first success in SAW rotary motor operating at 9.85 MHz, a smaller rotary motor is designed. With the operating frequency of 30 MHz and the driving voltage of 120 V(p-p), the motor can rotate at a speed of 270 rpm.

Acoustics↗

PubMed2001

Ordered valence-bond states in symmetric two-dimensional spin-orbital systems.

We consider a superexchange Hamiltonian, H = -SUM ( )(2S(i) . S(j)-(1/2)) (2T(i) . T(j)-(1/2)), which describes systems with orbital degeneracy and strong electron-phonon coupling in the limit of large on-site repulsion. In an SU(4) Schwinger boson representation, a reduced spin-orbital interaction is derived exactly, and a mean field theory has been developed. In one dimension, a spin-orbital liquid state with a finite gap is obtained. On a two-dimensional square lattice a novel type of spin-orbital ferromagnetically ordered state appears, while spin and orbital are antiferromagnetic. An important relation has been found, relating the spin and orbital correlation functions to the combined spin-orbital ones.

Journal Article↗

PubMed2001

Mesoscopic Kondo screening effect in a single-electron transistor embedded in a metallic ring.

We study the Kondo screening effect generated by a single-electron transistor or quantum dot embedded in a small metallic ring. When the ring circumference L becomes comparable to the fundamental length scale xi(0)(K) = Planck's constant over upsilon(F)/T(0)(K) associated with the bulk Kondo temperature, the Kondo resonance is strongly affected, depending on the total number of electrons (mod4) and magnetic flux threading the ring. The resulting Kondo-assisted persistent currents are also calculated in both Kondo and mixed-valence regimes, and the maximum values are found in the crossover region.

Journal Article↗

PubMed2001

Marginal Fermi liquid resonance induced by a quantum magnetic impurity in d-wave superconductors.

We consider a model of an Anderson impurity embedded in a d(x(2)-y(2))--wave superconducting state to describe the low-energy excitations of cuprate superconductors doped with a small amount of magnetic impurities. Because of the Dirac-like energy dispersion, a sharp localized resonance above the Fermi energy, showing a marginal Fermi liquid behavior ( omega ln omega as omega-->0), is predicted for the impurity states. The same logarithmic dependence of self-energy and a linear frequency dependence of the relaxation rate are also derived for the conduction electrons, characterizing a new universality class for the strong coupling fixed point. At the resonant energies, the spatial distribution of the electron density of states around the magnetic impurity is also calculated.

Journal Article↗

PubMed2001

Applied anatomy of the axillary nerve for selective neurotization of the deltoid muscle.

Morphologic and internal topographic features of the axillary nerve were studied in 40 cadaveric shoulders to provide anatomic data for selective neurotization of the deltoid muscle in axillary nerve injury. The axillary nerve can be divided into three segments. Proximal to the subscapularis muscle, the axillary nerve is a single nerve trunk. Nerve fascicles to the deltoid muscle are identified at its lateral part. In front of the subscapularis muscle, the axillary nerve forms into the lateral and medial fasciculi groups. Distal to the subscapularis muscle, the nerve divides into anterior and posterior branches, which are continuations of the lateral and medial fasciculi groups, respectively. The anterior branch contains all fibers that innervate to the anterior and middle deltoid muscle. In 90% of cases, the posterior branch contains part or all nerve fibers to the posterior deltoid muscle. Nerve fibers to the teres minor and cutaneous sensory fibers are found in the posterior branch. In neurotization of the deltoid muscle, the best approach is to match the donor nerve to the lateral fasciculi group, which will give the highest percentage of reinnervation of the deltoid muscle.

Adult↗

PubMed2001

[Analyses of chromosomal karyotypes and cytogenetic variations of animal cell lines].

After the master cell stock(mcs) and working cell bank of more than 30 different strains of 7 animal kidney cell lines (F-81 or CRFK cell line, MDCK cell line, Vero or Vero-2 cell line, MA-104 cell line and BHK-21 cell line) were established in China, the chromosomal number variations and structural aberrations of the above lines, primary feline or canine kidney cell (FKC or CKC) and HeLa cell line were investigated and their karyotypes of routine or Giemsa chromosomal bands were analyzed. The carcinogenesis or tumorigenicity testing of these cells in about 700 nude mice and for colony formation in soft agar (SA) and for agglutination under different concentration of plant lectins was carried out. Both tumorigenicity-negative strains of F-81, CRFK, Vero or Vero-2 lines and very-low-tumorigenicity strains of MDCK line were successfully selected and evaluated for the production of canine or feline combination viral vaccines, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity. Rate of modal chromosome number represents the ratio of cell number having modal chromosome number to all the split cell number analyzed at random. Rate of difference represents the ratio of difference of the rate of modal chromosome number between mcs (master cell stock) + n and mcs passages. The chromosomal analysis results showed that the ratio of difference of the rate of modal chromosome number between mcs + n and mcs passages was not more than 5%-15% and the structure aberrations was generally 0%-3%, not more than 5%-10%, thus the hereditary character of cell lines is comparatively stable without significant difference between different passages. The genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species specific. Experimental models were established for the researches on the prevention and prophylaxis of malignant tumors or cancers and their genetically biological characteristics. Tests showed that there was correlation among cell line chromosome number variations, anchorage independence in soft agar, agglutination under plant lectins and tumor-forming ability in nude mice. Since testing in vitro is more economic, simpler, faster, and is thought to be reliable, we recommend plant lectins followed by SA or analysis of karyotypes as the initial means for monitoring tumorigenicity of animal cell line in nude mice.

Animals↗

PubMed2000

Vascular anatomic variations in second toe transfers.

To devise a new classification of vascular variations in second toe transfer we analyzed the anatomic details of the first dorsal metatarsal artery in 304 cases of second toe transplantation and the venous structure in 200 cases. According to location, the arterial vascularity was classified as superficial (18% of cases), intramuscular (54%), inframuscular (23%), and absent (5%). According to diameter, it was classified into large (16%), medium (64%), and small (20%). Based on branching pattern, the artery was classified into ramifying type (88%), main trunk (4%), and fine branch type (8%). The venous drainage of the second toe was categorized as greater saphenous vein main trunk type, greater saphenous vein fine branch type, dorsal digital vein main trunk type, and dorsal digital vein fine branch type. Variations of the first dorsal metatarsal artery are common. Classification should be done according to its location, diameter, and branching pattern at the toe web. Regardless of location, big vessels entering the second toe are the most important attribute for successful outcome.

Adolescent↗

PubMed2000

Comparison of effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides.

AIM: To investigate the characterization of pharmacological action & of CH50, a recombinant polypeptide of human fibronectin, by comparing the effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides (LPS). METHODS: The production of nitric oxide (NO) as an index macrophage activation was determined by colorimetric assay. The interferon-gamma (IFN-gamma) transfection was performed with coprecipitation of calcium phosphate and DNA. The melanoma B16 cells were inoculated into abdominal cavity of mice and the number of tumor nodes was recorded. RESULTS: At lower concentrations or when given alone in vitro, CH50 produced ten times less NO than LPS (P < 0.01). But at concentrations higher than 1 mg.L-1, CH50 activated the IFN-gamma-primed macrophages to produce NO to the same extent as LPS (P > 0.05). There was no synergism between CH50 and LPS. Both CH50 and LPS alone could reduce the number of tumor nodes in abdominal cavity of mice but CH50 had a stronger inhibitory effect on the growth of tumor in vivo as compared to LPS (P < 0.01). CH50/IFN-gamma had also a better inhibitory effect on tumor growth in vivo than LPS/IFN-gamma did. CONCLUSION: In the presence of IFN-gamma, the ability of CH50 to activate macrophages is the same as that of LPS. But CH50 has better antitumorogenic effects in vivo against mouse melanoma as compared to LPS.

Animals↗

PubMed1999

Effect of recombinant human fibronectin polypeptide CH50 on growth and metastasis of melanoma.

AIM: To study the effect of recombinant human fibronectin polypeptide CH50 on murine melanoma growth and metastasis, and its antitumor mechanism. METHODS: Mouse and melanoma B16 cell tests were used to observe antitumor effect and mechanism of CH50. RESULTS: CH50 markedly inhibited melanoma growth and experimental lung metastasis. The melanoma weight was reduced from (2.3 +/- 1.2) g of control group to (0.7 +/- 0.8) g of test group (P < 0.05). CH50 at 0.125, 0.25, 0.5 mg/mouse reduced melanoma lung metastatic colonies from 87 +/- 49 of control group to 34 +/- 6, 14 +/- 12, 4 +/- 2, respectively. CH50 adhered to melanoma B16 cells and inhibited adhesion of B16 cells to laminin. CH50 enhanced the cytotoxicity of macrophages to melanoma B16 cells. CONCLUSION: CH50 inhibited tumor growth and metastasis of murine melanoma. The antitumor effect of CH50 is related to its adhesion ability to melanoma B16 cells and enhancing macrophage cytotoxicity.

Animals↗

PubMed1998

Long-term functional results of contralateral C7 transfer.

From 1986 to 1994, 82 patients with brachial plexus root avulsion were operated on using a contralateral C7 nerve-root transfer. Forty-four patients underwent a one-stage procedure in which the distal end of the ulnar nerve was anastomosed to the contralateral C7 root, and the other 38 underwent a two-stage procedure (first phase: C7 root --> ulnar nerve; second phase: ulnar nerve --> recipient nerve). Twenty postoperative cases were followed-up for 2 years. Of them, the ulnar nerve was transferred to the musculocutaneous nerve in six cases, with recovery of the biceps up to M3 in four and S3 in five cases; the ulnar nerve was transferred to the median nerve in eight cases, with recovery of the wrist and finger flexors up to M3 in five and S3 in six cases; the ulnar nerve was transferred to the radial nerve in four cases, with recovery of the triceps up to M4 in two and S3 in three cases; and the ulnar nerve was transferred to the thoracodorsal nerve in two cases, with recovery of the latissimus dorsi to M4 in one case. The total muscle recovery rate (up to M3) of the series was 60 percent, and the sensory recovery rate (S3) was 78 percent. Outcomes were related to patient age, operative delay, and whether or not the ulnar nerve was used as a bridge for transfer.

Adolescent↗

PubMed1998

Femoral nerve transfer for treatment of brachial plexus root avulsion.

Femoral nerve transfer to the muscular branches of the thenar and hypothenar muscles was performed to determine its protective effect on the hand intrinsic muscles. Seven cases of brachial plexus root avulsion treated from May of 1989 to October of 1991 were involved. The femoral nerve transfer to the muscular branches of the thenar and hypothenar muscles was done at the same stage of multiple neurotization. The muscular branches derived from the femoral nerve were isolated and coapted with the thenar muscle branch of the median nerve and the deep branch of the ulnar nerve. A groin flap was harvested simultaneously to form a skin-tube pedicle that covered the nerve bridge. At the second stage, when regeneration of the median and ulnar nerves was found to reach as far as the level of the wrist, the femoral nerve was divided and the muscular branches of the thenar and hypothenar muscles were anastomosed with the regenerated median and ulnar nerves. All the cases were followed up for more than 6 years. Six months after femoral nerve transfer, muscle power of the interosseous muscles and adductor pollicis recovered to MRC3, whereas that of the abductor pollicis brevis recovered to MRC1 to 2. Five cases underwent second-stage transfer. Four to five years of follow-up revealed that the muscle power of the interosseous muscles and adductor pollicis was MRC2 in one case, MRC1 in three cases, and MRC0 in one case. As for the donor area, muscle power of the quadriceps femoris reduced to M3 to 4 within 1 month after femoral nerve transfer and recovered to normal at 3 months. In conclusion, femoral nerve transfer to the muscular branches of the thenar and hypothenar muscles has some protective effect on the hand intrinsic muscles. The outcome of the second stage, however, is not satisfactory.

Adolescent↗

PubMed1997

Long-term results of toe transfer: retrospective analysis.

Between February 1966 and February 1994, 400 cases of toe transplantation were analyzed, to evaluate toe-transfer procedures in thumb and finger reconstruction. Techniques utilized included single second-toe transfer, with and without the metatarsophalangeal joint (299): second- and third-toe transfer (28); second-toe and third proximal phalanx transfer (1); second-toe with flap transfers (66); and hallux nail flap with second toe or second and third toe transfer (6). There was a survival rate of 96.5 percent, with 386 cases surviving and 14 failing. A more than 2-year follow-up was possible in 240 cases. Excellent motor and sensory function (more than 90 percent of normal) was achieved in the reconstructed fingers and thumbs, as well as satisfactory function (between 86 and 91 percent of normal) in the donor foot.

Adolescent↗

PubMed1996

Corepression of RelA and c-rel inhibits immunoglobulin kappa gene transcription and rearrangement in precursor B lymphocytes.

Multiple members of the NF-kappa B/Rel protein family are induced during B cell differentiation and have been implicated in transcriptional activation of the immunoglobulin kappa (Ig kappa) locus. Despite these findings, normal numbers of Ig kappa + B lymphocytes are produced by mice bearing targeted mutations in individual NF-kappa B/Rel genes. In the present study, precursor B lymphocytes were engineered to express a trans-dominant form of I kappa B alpha that simultaneously impairs the c-Rel and RelA transactivating subunits of NF-kappa B. This dual block in NF-kappa B/Rel signaling led to potent inhibition of germline Ig kappa transcription and rearrangement, whereas recombinase activity was unaffected. These findings suggest that c-Rel and RelA serve compensatory functional roles in the developmental mechanisms that govern Ig kappa gene assembly.

Animals↗

PubMed1995

Anatomic study of a new axial skin flap based on the cutaneous branch of the medial plantar artery.

A new axial skin flap based on the middle cutaneous branch of the medial plantar artery was evaluated in 33 fresh cadaver legs. The vascular pedicle of the skin flap is based on the middle cutaneous artery, its venae comitantes, and segments of the great saphenous vein, if necessary. The middle cutaneous artery is the largest cutaneous branch, arising from the medial plantar artery 2.5 cm distal to its origin. The diameter of its origin is 1.2 mm, and its pedicle is 2 cm long. The midline of the flap runs from the first web space to the heel tip. The upper and lower borders of the flap are 3 to 4 cm on either side of this line. The upper border is medial to the extensor hallucis tendon, and the lower border is medial to the abductor hallucis. Distally, the border begins 2 cm proximal to the metatarsalphalangeal joint; proximally, the border is at the middle of the medial malleolus. The flap diameter can be up to 8 x 12 cm. The middle cutaneous branch of the medial plantar artery was found in all cadaver specimens, except for one with a common trunk. The new flap design leaves the major blood supply to the foot and the plantar aponeurosis intact. It is easy to harvest and may be used either as an island flap or free flap.

Arteries↗

PubMed1994

Effect of diallyl trisulfide on the activation of T cell and macrophage-mediated cytotoxicity.

At high concentration (50 micrograms/ml), diallyl trisulfide (DATS) had an inhibitory effect on T cell activation (compared with control group, P < 0.05). But at appropriate concentrations (3.125-12.5 micrograms/ml), DATS augmented the activation of T lymphocytes by Con A (compared with control group, P < 0.01). The augmentation of T cell activation by DATS was related to its inhibitory effect on the production of nitric oxide (NO) by macrophages. In a wide range of concentrations (1-100 micrograms/ml), DATS can inhibit the production of NO by macrophages (P < 0.05, P < 0.01). In addition, DATS can antagonize the inhibition of tumor-derived immunosuppressive factors produced by S180 cells and Ehrlich ascitic cancer cells on the activation of T cells, and reduce the inhibitory rate significantly (P < 0.01). DATS, despite its inhibition of the production of NO by macrophages, can significantly enhance the production of hydrogen peroxide (H2O2) by macrophages. When macrophages were pretreated with DATS for 24 h, the cytotoxicity % of macrophages to three tumor cell lines was significantly higher than that in corresponding control group (P < 0.05, P < 0.01). In the presence of both DATS and LPS, the cytotoxicity of macrophages was further enhanced so that the cytotoxicity % of macrophages to tumor cells was significantly higher than either that in the presence of DATS alone or that in the presence of LPS alone (P < 0.05, P < 0.01). These results indicate that DATS can augment the activation of T cells and enhance the anti-tumor function of macrophage, suggesting that DATS may be potentially useful in tumor therapy.

Allyl Compounds↗