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Biomedical subjects

Yong Tang

Publications and source records attributed to Yong Tang.

At least 55 records · Page 3Linked to original sources
PubMed2004

Myelinated nerve fibres in the subcortical white matter of cerebral hemispheres are preserved in alcoholic subjects.

Previous studies have found that the primary change in the brain of chronic alcoholics is a selective loss of white matter in cerebral hemispheres. It is unknown whether the loss of white matter is due to alcohol-induced degeneration of axons in white matter, and this hypothesis has never been tested. We used a newly developed stereological method to investigate whether the length and diameter of myelinated fibres change in the subcortical white matter of male alcoholic subjects. We found no significant differences between control and alcoholic subjects with respect to the total volume, total length, and mean diameter of myelinated fibres in white matter. Our results do not find any support for the hypothesis that chronic alcoholic subjects may suffer from a degeneration of axons (myelinated fibres) in white matter in cerebral hemispheres.

Alcoholism↗
PubMed2004

Bispecific minibodies targeting HER2/neu and CD16 exhibit improved tumor lysis when placed in a divalent tumor antigen binding format.

Unconjugated monoclonal antibodies have emerged as important therapeutic agents for selected malignancies. One mechanism by which antibodies can exert cytotoxic effects is antibody-dependent cellular cytotoxicity (ADCC). In an effort to increase the efficiency of ADCC at tumor sites, we have focused on the construction of bispecific antibodies specific for the tumor antigen HER2/neu and the Fc gamma RIII-activating receptor (CD16) found on NK cells, mononuclear phagocytes, and neutrophils. Here, we describe the production of bispecific minibodies in two distinct binding formats. The parent minibody was constructed such that the IgG1 C(H)3 constant domain serves as the oligomerization domain and is attached to an anti-CD16 and an anti-HER2/ neu single-chain Fv via 19- and 29-amino acid linkers, respectively. This molecule can be expressed in mammalian cells from a dicistronic vector and has been purified using sequential affinity purification techniques. Analysis by surface plasmon resonance shows that the bispecific minibody can bind to HER2/neu and CD16, both individually and simultaneously. Furthermore, cytotoxicity studies show that the minibody can induce significant tumor cell lysis at a concentration as low as 20 nm. A trimeric, bispecific minibody (TriBi) that binds dimerically to HER2/neu and monomerically to CD16 induces equivalent cytotoxicity at lower antibody concentrations than either the parent minibody or the corresponding single-chain dimer. Both minibody constructs are stable in mouse and human serum for up to 72 h at 37 degrees C. These minibodies have the potential to target solid tumors and promote tumor lysis by natural killer cells and mononuclear phagocytes.

Animals↗
PubMed2004

Synthesis and characterization of pentaerythritol-derived oligoglycol and their application to catalytic Wittig-type reactions.

Several pentaerythritol-derived oligoglycols 1 with free hydroxyl groups are readily prepared by a convergent approach. Quantitative (13)C NMR proves to be an efficient tool for the characterization of oligoglycols. The corresponding telluride of oligoglycol 17 is synthesized and used as a good catalyst for Wittig-type reactions in preparing both disubstituted and trisubstituted olefins in good to high yields.

Journal Article↗
PubMed2004

Diastereoselectivity-switchable and highly enantioselective 1,3-dipolar cycloaddition of nitrones to alkylidene malonates.

Trisoxazoline 1/Co(ClO(4))(2).6H(2)O catalyzed the 1,3-cycloaddition between nitrones 3 with alkylidene malonates 2 at 0 degrees C to give the isoxazolidines with both high enantioselectivity and high exo selectivity. However, when the temperature was lowered from 0 to -40 degrees C, the same cycloaddition afforded endo isomers as the major products with good to high enantioselectivity. A mechanism is provided.

Journal Article↗
PubMed2004

Controllable enantioselective Friedel-Crafts reaction between indoles and alkylidene malonates catalyzed by pseudo-C3-symmetric trisoxazoline copperII complexes.

Pseudo-C(3)-symmetric trisoxazoline copper(II) complexes prove to be excellent catalysts in the Friedel-Crafts alkylation of indoles with alkylidene malonates. The absolute stereochemistry of this reaction is shown to be dependent on the solvent. Reactions in isobutyl alcohol afford the Friedel-Crafts alkylation adducts in excellent yields and with up to +98% ee. In 1,1,2,2-tetrachloroethane (TTCE), however, the opposite enantiomers of the products are obtained in good yields with up to -89% ee. Water tolerance of chiral catalyst trisoxazoline 2a/Cu(OTf)(2) is examined, and it is found that the addition of up to 200 equiv of water relative to catalyst in isobutyl alcohol has almost no effect on enantioselectivity but slows down the reaction. The reaction scope is studied as well. The roles of alcohol as the solvent to accelerate the reaction are discussed. The stereochemical models of asymmetric induction for reactions both in isobutyl alcohol and in TTCE are also developed.

Journal Article↗
PubMed2004

Estrogen replacement increases spinophilin-immunoreactive spine number in the prefrontal cortex of female rhesus monkeys.

While studies have shown that estrogen affects hippocampal spine density and function, behavioral studies in humans and nonhuman primates have also implicated the prefrontal cortex in the effects of estrogen on cognition. However, the potential for similar estrogen-induced increases in spines and synapses in the prefrontal cortex has not been investigated in primates. Moreover, it is not known if such an estrogen effect would be manifested throughout the neocortex or primarily in the regions involved in cognition. Therefore, we investigated the effects of estrogen on dendritic spines in the prefrontal and primary visual cortices of young rhesus monkeys. Young female monkeys were ovariectomized and administered either estradiol cypionate or vehicle by intramuscular injection. Using an antibody against the spine-associated protein, spinophilin, spine numbers were estimated in layer I of area 46 and in layer I of the opercular portion of area V1 (V1o). Spine numbers in layer I of area 46 were significantly increased (55%) in the ovariectomy + estrogen group compared to the ovariectomy + vehicle group, yet spine numbers in layer I of area V1o were equivalent across the two groups. The present results suggest that estrogen's effects on synaptic organization influence select neocortical layers and regions in a primate model, and provide a morphological basis for enhanced prefrontal cortical functions following estrogen replacement.

Animals↗
PubMed2004

Unbiased quantification of the microdissected human Scarpa's ganglion neurons.

OBJECTIVE: The objective of the present study was to obtain unbiased estimates of the total number of Scarpa's vestibular ganglion neurons in individuals with normal vestibular function. STUDY DESIGN: Application of unbiased stereology using microdissected human temporal bone specimens. METHODS: Postmortem temporal bones were obtained from five young subjects with no history of audiovestibular disease (age range 42-49 years). The vestibular nerve containing the Scarpa's ganglion was microdissected, embedded in paraffin, and cut into 40 microm serial sections. Unbiased estimates of the total number of neurons were obtained using the optical fractionator technique of stereology. RESULTS: An average of 23,599 (coefficient of variation [CV] = 0.11) vestibular ganglion neurons was obtained. There was no significant difference between the results obtained from the microdissected specimens and results that had been obtained from an age-matched group derived from a previously published report from our laboratory using archival human temporal bone specimens. CONCLUSIONS: This study represents the first report to demonstrate the combination of the microdissection technique and the unbiased stereologic technique in the human temporal bone. This study demonstrates the reliability of the microdissection technique as an alternative method of human temporal bone processing for unbiased stereology. The utility of the microdissection technique is that specimens can be used for quantification, immunohistochemistry, and other powerful applications.

Adult↗
PubMed2004

Accelerating tissue expansion by application of topical papaverine cream.

The rate of tissue expansion can be accelerated by papaverine through a special delivery system, according to an early report. Because the delivery system was complex and inconvenient, another means of administrating papaverine was tested to observe the rate of tissue expansion. In this study, 24 miniature pigs were divided equally into three groups. Four 150-ml silicone expanders were implanted into each pig in groups A and C. Four modified rectangular silicone expanders were also implanted into each animal in group B. During the expansion process, 1 g of 2% hydrochloride papaverine cream was applied topically onto the surface of each pig's expanding skin in group A two times daily, and hydrochloride papaverine solution was injected into the outer shell of each modified expander in group B weekly. Group C acted as the control group. The mean sum of the first four times of saline water volume that was injected into the expanders was 142.42 +/- 5.6 ml in group A, 128.72+/-4.8 ml in group B, and 106.38+/-3.28 in group C. There were statistical differences among the three groups. The mean sum of volume saline water that was injected into hind expanders was 137.51 +/- 5.1 ml in group A, 120.35 +/- 3.6 ml in group B, and 102.63 +/- 4.76 ml in group C, and there was a statistical difference among the three groups as well. There was no statistically significant difference in the thickness of fibrous capsules among the three groups. This study shows that the rate of tissue expansion can be accelerated by topical application of papaverine cream, and the rate is better than the rate of tissue expansion induced by the special drug delivery system.

Administration, Topical↗
PubMed2004

[Study on antitumor and synergy effect of "bushen huayu jiedu formula" on mice hepatocarcinoma H22].

OBJECTIVE: To explore antitumor and synergy effect of "Bushen Huayu Jiedu Formula" (BSHYJDF) on hepatocarcinoma H22. METHODS: Transplanted hepatocarcinoma H22 mice were used, the inhibitory rates of H22 were observed respectively to BSHYJDF and BSHYJDF combined with cisplatin (DDP). RESULTS: BSHYJDF could significantly inhibit hepatocarcinoma H22 in transplanted mice (P < 0.05). CONCLUSION: BSHYJDF had inhibitive effect and synergy with chemotherapy to a certain extent in transplanted hepatocarcinoma mice.

Animals↗
PubMed2004

Influence of cryopreserved olfactory ensheathing cells transplantation on axonal regeneration in spinal cord of adult rats.

OBJECTIVE: To observe the effects of cryopreserved olfactory ensheathing cells (OECs) transplantation on axonal regeneration and functional recovery following spinal cord injury in adult rats. METHODS: Twenty-four rats were divided into experimental and control groups, each group having 12 rats. The spinal cord injury was established by transecting the spinal cord at T10 level with microsurgery scissors. OECs were purified from SD rat olfactory bulb and cultured in DMEM (Dulbecco's minimum essential medium) and cryopreserved (-120 degree) for two weeks. OECs suspension [(1-1.4)x10(5)/ul] was transplanted into transected spinal cord, while the DMEM solution was injected instead in the control group. At 6 and 12 weeks after transplantation, the rats were evaluated with climbing test and MEP (moter evoked potentials) monitoring. The samples of spinal cord were procured and studied with histological and immunohistochemical stainings. RESULTS: At 6 weeks after transplantation, all of the rats in both transplanted and control groups were paraplegic, and MEPs could not be recorded. Morphology of transplanted OECs was normal, and OECs were interfused with host well. Axons could regrow into gap tissue between the spinal cords. Both OECs and regrown axons were immunoreactive for MBP. No regrown axons were found in the control group. At 12 weeks after transplantation, 2 rats (2/7) had lower extremities muscle contraction, 2 rats (2/7) had hip and/or knee active movement, and MEP of 5 rats (5/7) could be recorded in the calf in the transplantation group. None of the rats (7/7) in the control group had functional improvement, and none had MEPs recorded. In the transplanted group, histological and immunohistochemical methods showed the number of transplanted OECs reduced and some regrown axons had reached the end of transected spinal cord. However, no regrown axons could be seen except scar formation in the control group. CONCLUSIONS: Cryopreserved OECs could integrated with the host and promote regrowing axons across the transected spinal cord ends.

Animals↗
PubMed2004

[Purification of recombinant humanized anti-HBsAg Fab antibody by affinity chromatography].

AIM: To establish a steady purification method for producing recombinant humanized anti-HBsAg Fab from yeast fermentation supernatant. METHODS: Humanized anti-HBs scFv was used to immunize BALB/c mice to obtain anti-scFv monoclonal antibody (mAb) which was used to purify recombinant humanized anti-HBsAg Fab from yeast fermentation supernatant by affinity chromatography. RESULTS: The purity of purified recombinant anti-HBsAg Fab was above 95% and its recovery rate was about 75%-85%. CONCLUSION: An efficient affinity chromatography suitable for purification of recombinant humanized anti-HBsAg Fab in large-scale was established.

Animals↗
PubMed2004

[Improvement of the model of pancreas-duodenal transplantation in swines].

OBJECTIVE: To improve the procedures of pancreas-duodenal transplantation in swines in order to establish a technically stable model that accords with the physiological situation. METHODS: The whole pancreatoduodenal graft was harvested with in situ flush using 4 degrees C preservation solution. Type 1 diabetes was induced surgically by total pancreatectomy. By end-to-side fashion, the segment of abdominal aorta containing the celiac artery and the anterior mesenteric artery (equal to superior mesenteric artery in human) was anastomosed to the abdominal aorta of recipient which is behind the renal artery, the portal vein was anastomosed to the anterior mesenteric vein of the recipient, the duodenum was anastomosed to the jejunum of the recipient. The graft was placed in the anterior right peritoneal cavity. RESULTS: A total of 28 swines were used as recipients. Of them, two died of anesthetic accident, another two died of hyperacute rejection 2 hours, 19 hours after operation respectively; the others underwent the operation uneventfully. Their survival time was 5-21 days, blood sugar was (11.33+/-1.66) mmol/L on the first day after operation, and (5.65+/-0.89) mmol/L on the third day. CONCLUSION: This kind of model is stable, and the operative method and procedures are relatively simple and practicable.

Animals↗
PubMed2004

[Study on tissue culture of pasqueflower].

OBJECTIVE: To speed up seedling production of pasqueflower (Puzlsatilla chinenses) and their modernization in pasqueflower. METHOD: With tissue culture method, primary culture of different explants, culture of cluster buds and their rooting culture were conducted on medium of treatment combinations of adding different hormones. RESULT: The appropriate medium for different culture stages were MS + 6-BA 1.0-3.0 mg x L(-1) + NAA 0-0.05 mg x L(-1) + Sucrose 30 g x L(-1) in primary culture, MS + 6-BA 0.2 mg x L(-1) + NAA 0.02 mg x L(-1) + BR 0.00001 mg x L(-1) + Sucrose 30 g x L(-1) in differentiation and subculture of cluster buds, 1/2 MS + NAA 0.4 mg x L(-1) + Sucrose 20 g x L(-1) in rooting. CONCLUSION: Applying stem tip and flower buds as explants, high frequency propagation of seedlings can be achieved with plant tissue culture in Pasqueflower.

Flowers↗
PubMed2004

[Reconstruction of the mentum in the surgical management of cervical scar contracture].

OBJECTIVE: To investigate the effects of the reconstruction of the mentum with cervical tissue flaps in the surgical management of postburn cervical scar contracture. METHODS: Thirteen postburn patients with severe cervical scar contracture and mental deformity were enrolled in the study. The platysma flap (3 cases), scar tissue flap (6 cases) and cervical deep fascia tissue flap (3 cases), with the pedicle containing the facial and the superior thyroidal artery, were turned upwards to replenish mental soft tissue, and to form new mentum and sulcus mentolabialis. The cervical scars were repaired with expanded flap (11 cases), free flap (1 case) or trapezius muscular flap. RESULTS: The post-operative cervical configuration was found to be good, and the tissue flaps for mental reconstruction healed satisfactorily. Ten patients were followed-up for 6 to 24 months. All flaps were successful and achieved good results, except that scar formation was found in the cervical linear incision in 4 patients. CONCLUSION: Transfer of the platysma flaps, scar tissue flaps, or deep cervical fascial flaps for the reconstruction of cervical scar were simple and effective. The use of cervical scar tissue flaps could not only loose the constructed scar, but also beneficial in rectifying the configuration of the chin.

Adolescent↗
PubMed2004

[Experimental study on inhibition of skin graft contraction with papaverine cream].

OBJECTIVE: To evaluate the effect of exteral use of papaverine cream on enhancement of skin graft. METHODS: Five mini-pigs were used for the study. 20 full-thickness wounds were created on the back of each animal. Along the midline of the abdomen, a 40 cm x 2 cm full-thickness skin graft was harvested and the wound sutured.The full-thickness graft was prepared and trimmed to 2 cm x 2 cm of 0.6 mm thickness split-skin grafts, which were transplanted to each wound with tie-over bolsters. The sutures were removed 2 weeks after the operation. Twelve pairs of 100%-survived skin grafts were selected and divided into group A (the left side) and group B (the right side), with each pair locating on the same and opposite position. From the day of suture removal, 2% papaverine cream was used to group A while plain cream was used to group B. The grafts were measured and observed for healing condition at the time of suture removal and the first, second, third, fourth, fifth, and sixth month. The surface area of the graft was measured and the shrinking ratio was calculated. After the animals were killed at the sixth month, samples of the skin grafts were taken and processed with 10% formalin, routine paraffin wax and Hematoxylin-eosin staining. The tissue structure was observed and the results were analyzed statistically. RESULTS: The grafts in two groups did not have significant differences at the time of suture removal. Observations from the first to the sixth month showed that the two groups had significant differences in skin graft contracture and histological changes. HE stains demonstrated that the skin grafts in group A had less fibroblasts, more microvessels and orderly-arranged collagenous fibers. CONCLUSIONS: External use of papaverine cream can inhabit the contraction of skin grafts. It is a safe, effective, simple, and reliable method,which has the advantages of easy delivery,cheapness, less injury and infection,and no side effects.

Animals↗