Biomedical subjects

Chun-Fu Dai

Publications and source records attributed to Chun-Fu Dai.

7 recordsLinked to original sources

PubMed2006

Reanimation of paralyzed laryngeal muscles by electrical stimulation synchronized with inspiration.

OBJECTIVE: To determine the effects of electrical stimulation on denervated cat posterior cricoarytenoid (PCA) muscle. STUDY DESIGN AND SETTING: This study was conducted on six cats with PCA muscle denervation. All animals were sacrificed 12 weeks after surgery and the glottal area in the live animals and the fiber diameters of PCA muscle were obtained. RESULTS: Signals synchronized with inspiration were recorded and transmitted to stimulate PCA muscle. The abduction of the paralyzed vocal cord during inspiration was observed; this allows enough flow of air through the larynx to maintain the respiration. The stimulated fiber diameters of PCA muscle were different from that of nonstimulated (P < 0.01). Although all denervated muscles were degenerated, electrical stimulation was used to prevent muscular atrophy. CONCLUSIONS: This study indicates that electrical stimulation of the PCA muscle synchronized with inspiration could restore the abduction of a paralyzed vocal cord and prevent the denervated muscles from atrophying. SIGNIFICANCE: Electrical stimulation synchronized with inspiration may lead to reanimation of paralyzed laryngeal muscles.

Animals↗

PubMed2005

Electrical coupling and release of K+ from endothelial cells co-mediate ACh-induced smooth muscle hyperpolarization in guinea-pig inner ear artery.

The physiological basis of ACh-elicited hyperpolarization in guinea-pig in vitro cochlear spiral modiolar artery (SMA) was investigated by intracellular recording combined with dye labelling of recorded cells and immunocytochemistry. We found the following. (1) The ACh-hyperpolarization was prominent only in cells that had a low resting potential (less negative than -60 mV). ACh-hyperpolarization was reversibly blocked by 4-DAMP, charybdotoxin or BAPTA-AM, but not by N(omega)-nitro-L-arginine methyl ester, glipizide, indomethacin or 17-octadecynoic acid. (2) Ba(2)(+) (100 microm) and ouabain (1 microm) each attenuated ACh-hyperpolarization by approximately 30% in smooth muscle cells (SMCs) but had only slight or no inhibition in endothelial cells (ECs). A combination of Ba(2)(+) and 18beta-glycyrrhetinic acid near completely blocked the ACh-hyperpolarization in SMCs. (3) High K(+) (10 mm) induced a smaller hyperpolarization in ECs than in SMCs, with an amplitude ratio of 0.49 : 1. Ba(2)(+) blocked the K(+)-induced hyperpolarization by approximately 85% in both cell types, whereas ouabain inhibited K(+)-hyperpolarization differently in SMCs (19%) and ECs (35%) and increased input resistance. 18beta-Glycyrrhetinic acid blocked the high K(+)-hyperpolarization in ECs only. (4) Weak myoendothelial dye coupling was detected by confocal microscopy in cells recorded with a propidium iodide-containing electrode for longer than 30 min. A sparse plexus of choline acetyltransferase-immunoreactive (ChAT) fibres was observed around the SMA and its up-stream arteries. (5) Evoked excitatory junction potentials (EJP) were partially blocked by 4-DAMP in half of the cells tested. We conclude that ACh-induced hyperpolarization originates from ECs via activation of Ca(2)(+)-activated potassium channels, and is independent of the release of NO, cyclo-oxygenase or cytochrome P450 products. ACh-induced hyperpolarization in smooth muscle cells involves two mechanisms: (a) electrical spread of the hyperpolarization from the endothelium, and (b) activation of inward rectifier K(+) channels (K(ir)) and Na(+)-K(+) pump current by elevated interstitial K(+) released from the endothelial cells, these being responsible for about 60% and 40% of the hyperpolarization, respectively. The role ratio of K(ir) and pump current activation is at 8 : 1 or less.

Acetylcholine↗

PubMed2005

Modified stapes prosthesis to limit postoperative vertigo.

OBJECTIVE: To investigate the anatomic relationship between utricle, saccule, and stapes footplate, and adapt the stapes prosthesis tip to reduce postoperative vertigo. STUDY DESIGN: Five temporal bones were serially sectioned and stained, and the distance from the inner lining of stapes footplate to saccule and utricle, respectively, were measured. The Fisch prosthesis was modified with a slope of 45 degrees at its tip to adapt to the anatomic configuration of the vestibule. Fisch's original piston or the modified piston was used in 174 ears (Group I) and 108 ears (Group II), randomly. RESULTS: There was no statistically significant difference in hearing improvement between the 2 groups (P > 0.5). However, postoperative vertigo was significantly reduced when the modified prosthesis was inserted (P < 0.005). CONCLUSIONS: The modified piston improved the hearing to the level of the original piston, and the incidence of postoperative vertigo was significantly decreased. SIGNIFICANCE: A modified prosthesis is presented for a patient undergoing stapedotomy.

Adolescent↗

PubMed2002

Retrograde degeneration of the facial nerve after acute traction on parotid gland: an experimental investigation.

The parotid gland of the cat underwent traction for 2 hours (group A) or until the facial nerve was broken (group B). The cats survived postoperatively for 1 day, 2 weeks, 1 month, and 3 months, respectively. Each cat underwent an electroneurography session before they were killed. The facial nerve was harvested and underwent histologic examination. The present study demonstrated that, in group A, the degree of facial nerve degeneration indicated with evoked electroneurography was 100% at 1 day and 2 weeks and 85% and 35%, respectively, at 1 and 3 months after damage. In group B, no electric response was recorded, epineurium of extratemporal segment was broken. This study also showed that the pronounced alteration of the facial nerve following acute traction on the parotid gland was retrograde degeneration; it involved up to its internal acoustic meatus segment. Furthermore, pronounced damage was noted in its stylomastoid foramen and extratemporal segment.

Animals↗

PubMed2002

Apoptosis and expression of BCL-2 in facial motoneurons after facial nerve injury.

BACKGROUND: Apoptosis has been implicated in neuronal degeneration after optic and sciatic nerve injury. The mechanisms contributing to facial motoneuron death are poorly understood. This study investigated the mechanisms underlying facial motoneuronal death and the expression of BCL-2 in facial motoneurons after facial nerve injury. METHODS: Morphologic changes in the facial motoneurons were examined by light and transmission electron microscopy, and TdT-mediated dUTP-biotin nick end labeling (TUNEL) methods was used. Expression of BCL-2 was studied by immunohistochemistry and in situ hybridization after facial nerve injury. RESULTS: Cell shrinkage, condensed cytoplasm, and apoptotic bodies were demonstrated in numerous cells under light microscopy. The chromatin was condensed and localized to the nuclear envelope, forming a crescent or cap, and the endoplasmic reticulum was still visible but appeared swollen under electron microscopy. In vivo TUNEL staining displayed positive facial motoneurons 7 days after facial nerve transsection. The BCL-2 expression in facial motoneurons declined and reached its lowest level on the fifteenth day (p < 0.05). The reduction in BCL-2 expression after facial nerve transsection close to the facial motoneuron nucleus was greater than that of facial nerve transsection far away from the facial motoneuron nucleus (p < 0.05). BCL-2 expression after crushing of the facial nerve was found to be more intense in comparison with that after nerve transsection at the stylomastoid foramen (p < 0.05). CONCLUSIONS: These findings indicated that motoneuron death induced by facial nerve transsection was consistent with the process of apoptosis. The endogenous BCL-2 in these motoneurons may protect facial motoneurons from axotomy-induced cell death.

Animals↗

PubMed2002

Isolated sphenoid sinus disease: an analysis of 122 cases.

Isolated sphenoid sinus disease (ISSD) is a relatively uncommon disease. The present study is a retrospective review of 122 patients with ISSD who were treated at the Department of Otolaryngology, Eye, Ear, Nose and Throat Hospital at Shanghai Medical University over a 25-year period. The diagnosis of ISSD was made on the basis of history and physical examination, signs and symptoms, nasal endoscopy, and computed tomography (CT) and magnetic resonance imaging (MRI). The final diagnosis of ISSD was confirmed by histopathologic and microbiological examinations of the surgical specimens. The pathological findings in this study included sphenoid cyst (47 cases), sphenoid sinusitis (31 cases), fungal disease (19 cases), inverted papilloma (4 cases), sphenochoanal polyp (1 case), foreign body (8 cases), malignant tumors (8 cases), and others (4 cases). The most common initial symptom was headache, followed in decreasing order by visual changes, cranial nerve palsies, and nasal symptoms. The more frequent use of routine CT and MRI scanning, as well as endoscopy, in the diagnosis of sinus disease has led to an increase in the early diagnosis of ISSD. The recent advances in endoscopic sphenoidotomy has allowed for relatively safe and immediate treatment of ISSD, preventing late extension into adjacent vital structures, which is commonly fatal. Endoscopic surgery also enables the surgeon to make a precise pathological diagnosis.

Adolescent↗

PubMed2002

[Clinical and experimental study of treatment of nanmiqing capsule for chronic prostatitis].

OBJECTIVES: To investigate the clinical effect and therapeutic mechanism of Nanmiqing capsule made of rheum palmatum, leech, astragalus memberanaceus on patients with chronic prostatitis(CP). METHODS: Seventy-six CP cases were treated with Nanmiqing, while 32 CP cases were treated with Qianliekang as a control. The changes of EPS were observed pre- and post-treatment. The rat model of CP got by Xiaozhiling inducing were treated with Nanmiqing and Qianliekang respectively. The concentration of endothelin, TXB2, 6-keto-PGF1 alpha and SOD, IgG, IgA in plasma were measured pre- and post-treatment, meanwhile, pathological changes of prostate tissues were observed. RESULTS: The total effective rate was 89.47% in treatment group, which was significantly higher than 71.88% in the control group (P < 0.01). Experimental study for CP rats showed that the Nanmiqing was more effective medicine than Qianliekang (P < 0.01). CONCLUSIONS: Nanmiqing was an effective medicine for CP. The mechanism of clearing heat and resolving toxin, activating blood and removing stasis and reinforcing Qi in chinese medicine could be the explanation of the useful treatment including three therapentic ways.

6-Ketoprostaglandin F1 alpha↗