Biomedical subjects

Hongyan Jiang

Publications and source records attributed to Hongyan Jiang.

4 recordsLinked to original sources

PubMed2005

Light-induced shape-memory polymers.

Materials are said to show a shape-memory effect if they can be deformed and fixed into a temporary shape, and recover their original, permanent shape only on exposure to an external stimulus. Shape-memory polymers have received increasing attention because of their scientific and technological significance. In principle, a thermally induced shape-memory effect can be activated by an increase in temperature (also obtained by heating on exposure to an electrical current or light illumination). Several papers have described light-induced changes in the shape of polymers and gels, such as contraction, bending or volume changes. Here we report that polymers containing cinnamic groups can be deformed and fixed into pre-determined shapes--such as (but not exclusively) elongated films and tubes, arches or spirals--by ultraviolet light illumination. These new shapes are stable for long time periods, even when heated to 50 degrees C, and they can recover their original shape at ambient temperatures when exposed to ultraviolet light of a different wavelength. The ability of polymers to form different pre-determined temporary shapes and subsequently recover their original shape at ambient temperatures by remote light activation could lead to a variety of potential medical and other applications.

Journal Article↗

PubMed2005

NF-kappaB pathway protects cochlear hair cells from aminoglycoside-induced ototoxicity.

Cell death in outer hair cells of the mammalian inner ear induced by aminoglycoside antibiotics is mediated by reactive oxygen species (ROS) and can be prevented by antioxidants. The current study investigates the role of the nuclear factor (NF)-kappaB pathway in cell death or survival in adult CBA mice. Kanamycin (700 mg/kg subcutaneously, twice per day) progressively destroys hair cells but after 7 days of treatment auditory function and morphology are not yet affected significantly, permitting investigations of early events in drug-induced cell death. Immunostaining for 4-hydroxynonenal, indicative of lipid peroxidation, was elevated in the cochlea, but there was no effect on nitrotyrosine, a marker for peroxynitrite. NF-kappaB was increased at 3 hr, 3 days, and 7 days of treatment, with p50 and p65 proteins as its most abundant subunits. Immunoreactivity for p50 was present in nuclei of inner hair cells and supporting cells that survive the drug treatment. In contrast, nuclei of outer hair cells were devoid of label. Concomitant injections of antioxidants, however, such as 2,3-dihydroxybenzoic acid or salicylate (which prevent cell death induced by kanamycin), promoted the translocation of NF-kappaB into the nuclei of outer hair cells. In addition, kanamycin treatment decreased tyrosine phosphorylation of the inhibitory IkappaBalpha protein, leading to increased IkappaBalpha levels in the cochlea; the effect was reversed by cotreatment with antioxidants. These results suggest that changes in the redox state of the cochlea stimulate the activation of NF-kappaB and that this activation is cell protective.

Aldehydes↗

PubMed2002

[The expression of transforming growth factor alpha, beta 1 in hyperplastic tissue after endoscopic polypectomy and the effect of corticosteroid].

OBJECTIVE: To study the expression of transforming growth factor alpha, beta 1 in hyperplastic tissue after endoscopic polypectomy and the effect of corticosteroid. METHOD: Forty patients with nasal polyps were divided into two groups randomly: corticosteroid group (n = 20) with topical application of Budesonide (BUD, 400 micrograms/d) after endoscopic polypectomy and control group (n = 20) without corticosteroid after surgery. The hyperplastic tissues in operative cavity obtained in the 1st and 8th weeks after operation were studied with HE staining and immunohistochemistry technique respectively. RESULT: Morphological changes of hyperplastic tissue after endoscopic polypectomy included pseudostratified epithelium, highly edematous lamina proper and inflammatory cells infiltration, in which the main infiltrative cells were eosinophils (67.5%). Transforming growth factor alpha(TGF alpha) protein was highly expressed in epithelial cells, grand cells and inflammatory cells in the hyperplastic tissue. Transforming growth factor beta 1 (TGF beta 1) protein was highly expressed in inflammatory cells in the hyperplastic tissue. The expression of TGF alpha and beta 1 was significantly decreased after topical BUD spray (P < 0.01, 0.05). CONCLUSION: Transforming growth factor alpha and beta 1 may play an important role in the formation and recurrence of nasal polyps.

Adult↗

PubMed2002

[Dyspnea analyse and treatment to adult acute epiglottitis].

OBJECTIVE: To discuss the estimation and treatment of adult acute epiglottitis dyspnea. METHOD: 126 adult with acute epiglottitis patients were analyzed. RESULT: None of 30 patients undergone epiglotiotomy had asphyxia, inflammation diffuse or serious hemorrhage. 8 patients undergone tracheotomy, one patient undergone thyroericotomy but died. One of 87 patients with conservative treatment died. CONCLUSION: Gaspping, salivating and dyslogia are symbols of severe larynx obstruction. Fibrous laryngoscope is the best way of examine. Keeping respiratory path open and eliminating epiglottis swelling is the key of treatment.

Acute Disease↗