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Biomedical subjects

Yuming Yang

Publications and source records attributed to Yuming Yang.

7 recordsLinked to original sources
PubMed2006

A calixarene based fluorescent Sr2+ and Ca2+ probe.

A fluorescent probe, PyCalix, which has two pyrene moieties at the lower rim of a calix[4]arene fixed in the cone conformation was synthesized and its complexation behavior with alkali and alkaline earth cations was studied by fluorescence spectrometry. The compound showed intramolecular excimer emission at approximately 480 nm in the fluorescence spectra. Upon complexation with alkaline earth metal cations, a decrease of excimer emission was observed. The decrease of excimer emission was accompanied by an increase of monomer emission of pyrenes at 397 nm. The order of complexation constants of PyCalix with metal ions was Sr(+ approximately Ca2+ > Ba2+ > Mg2+ > K+ > Na+ > Cs+ for all reagents. PyCalix doped polyvinyl chloride (PVC) membrane was fabricated and our results showed that this membrane can be used for selective detection of Sr2+.

Journal Article↗
PubMed2004

Solvent-induced microphase separation in diblock copolymer thin films with reversibly switchable morphology.

We have studied the surface morphology of symmetric poly(styrene)-block-poly(methyl methacrylate) diblock copolymer thin films after solvent vapor treatment selective for poly(methyl methacrylate). Highly ordered nanoscale depressions or striped morphologies are obtained by varying the solvent annealing time. The resulting nanostructured films turn out to be sensitive to the surrounding medium, that is, their morphologies and surface properties can be reversibly switchable upon exposure to different block-selective solvents.

Journal Article↗
PubMed2004

The interaction of Schwann cells with chitosan membranes and fibers in vitro.

The bridging of nerve gaps is still one of the major problems in peripheral nerve regeneration. A promising alternative for the repair of peripheral nerve injuries is the bioartificial nerve graft, comprised of a biomaterial pre-seeded with Schwann cells (SCs), which is an effective substrate for enhancing nerve regeneration. Interaction between cultured SCs and biomaterials is of importance. For the purposes of this study, culture systems of normal SCs were used. The biocompatibility of chitosan, including chitosan membranes and chitosan fibers, was evaluated in vitro. The growth of SCs was observed by light and scanning electron microscopy at regular intervals. SCs were identified by immunocytochemical staining and the viability of SCs was measured by MTT assay. The experimental results indicated that SCs could grow onto chitosan materials with two different shapes: spherical and long olivary. They contacted with the extensions. The long olivary cells inclined to encircle chitosan fibers up. It was also found that the cells on the chitosan fibers migrated faster than those on the chitosan membranes. There was a good biological compatibility between chitosan and SCs. Compared with the chitosan membranes, SCs migrated more easily onto the stereoframe of chitosan fibers. These studies contribute information necessary to enhancing our understanding of biocompatibility of chitosan.

Animals↗
PubMed2002

[Microsurgical management of tethered cord syndrome].

OBJECTIVE: To assess the results of 26 patients with tethered cord syndrome (TCS) after microsurgical operation. METHODS: Twenty-six patients with TCS were treated microsurgically and their clinical data were analyzed retrospectively. RESULTS: 72% of the patients with TCS showed significant improvement. Surgical outcome was excellent in relieving pain and sensorimotor deficits, but bladder dysfunction. CONCLUSION: Early diagnosis and adequate surgical release are the keys to a successful outcome.

Adolescent↗
PubMed2002

[Diagnosis and treatment of subclinical pituitary apoplexy: report of 21 cases].

OBJECTIVES: To evaluate clinical manifestations of 21 patients with subclinical pituitary apoplexy and their diagnosis and treatment. METHOD: Clinical data from 21 patients with subclinical pituitary apoplexy treated from October 1989 to November 2001 were analyzed retrospectively. RESULTS: Their clinical manifestations included chronic headache, visual deficit and field cut. Three patients showed no clinical signs. Microsurgery was performed in 20 patients, of whom 3 were treated by emergency operation. Microsurgery included transsphenoidal decompression in 17 patients, and transpterioral approach in 3. One patient was given conservative therapy, and 12 were given endocrine replacement therapy. Nineteen patients recovered with marked visual improvement (7), partial improvement (8), no changes (4); deterioration was noted in 1. CONCLUSIONS: Subclinical pituitary apoplexy characterized by atypical clinical manifestations may be misdiagnosed or in appropriately treated. MRI is superior to CT scan for the diagnosis of subclinical pituitary apoplexy. Patients with persistent chiasmatic syndromes are indicated for emergency surgery. Endocrine replacement and transsphnoidal decompression are effective for the improvement of severe visual disturbance.

Adult↗