[Tumor-targeted human telomerase reverse transcriptase promoter/tk gene therapy against human nasopharyngeal carcinoma cells in vitro].

OBJECTIVE: To investigate the targeted killing effect of human telomerase reverse transcriptase promoter (hTERTp)/tk gene on human nasopharyngeal carcinoma (NPC) cells. METHODS: The recombinant plasmid hTERTp/tk/pGL3 was transfected into human NPC HNE1 cells and the expressions of TK and telomerase were investigated. The targeted killing effect induced by hTERTp/tk on HNE1 cells was assessed using RT-PCR and MTT assay. RESULTS: TK gene expression was detected in HNE1 cells transfected by hTERTp/tk/pGL3, and the cells showed reduced telomerase and hTERT expression as compared with the control cells. hTERTp/tk/pGL3 resulted in target killing of HNE1 cells but not of the normal control cells. The tumor cell-killing effect of hTERTp/tk/pGL3 was slightly milder than that of the positive control CMV/tk/pGL3 that produced nonselective cell killing. CONCLUSION: hTERTp/tk, a tumor-specific expression system, allows targeted tumor cell killing and reduces the activity of telomerase in NPC cells in vitro.

[Effect of surgical reconstruction of congenital aural atresia via the mastoid antrum approach: analysis of 48 cases].

OBJECTIVE: To assess the effect of surgical reconstruction of congenital aural atresia via the mastoid antrum approach and investigate method for preventing postoperative atresia of the reconstructed aural canal. METHODS: From 2000 to 2008, aural canal reconstruction and tympanoplasty was performed via the mastoid antrum approach. In 48 patients with congenital aural atresia (54 ears, including 45 ears of type II, 9 ears of type III). All the patients were followed-up for 18 months to assess the therapeutic effect. RESULTS: The mastoid antrum was located uneventfully for all the 54 ears, all showing ossicular chain anomalies involving most frequently the malleus and the incus followed by the upper structures of the stapes. Facial nerve abnormalities were seen in 23 ears (42.6%). Hearing improvement to over 20 dB was achieved in 45 ears (83.3%) and to over 25 dB in 25 ears (46.2%) one year later. CONCLUSION: The mastoid antrum approach for surgical reconstruction of congenital aural atresia is safe and reliable. Maintenance of the width of the aural canal and prevention of lateral healing of the transplanted tympanic membrane are crucial in the treatment of congenital aural atresia.

[Therapeutic effects of small fenestra stapedotomy with semiconductor diode laser: a comparison with microdrill].

OBJECTIVE: To compare the effects of small fenestra stapedotomy with semiconductor diode laser and microdrill in patients with otosclerosis. METHODS: Twenty-six patients (29 ears) undergoing stapedotomy with semiconductor diode laser and 19 patients (21 ears) with microdrill were compared for the hearing results and complication rates. RESULTS: No statistically significant differences were found in postoperative speech frequency and high frequency pure tone average in closing the air-bone gap between the two groups. The ears treated by stapedotomy with semiconductor diode laser showed significantly better preoperative minus the postoperative air-bone gap and milder dizziness. CONCLUSION: In spite of the good hearing outcomes in both groups, small fenestra stapedotomy with semiconductor diodelaser can achieve better results and reduce the incidence of complications.

[Therapeutic effect of insulin-like growth factor-1 injection into the inner ears through scala tympani fenestration on gentamicin-induced hearing loss in guinea pigs].

OBJECTIVE: To study the therapeutic effect of insulin-like growth factor-1 (IGF-1) injection into the inner ears through a scala tympani fenestration on sensorineural deafness in a guinea pig model of gentamicin-induced hearing loss. METHODS: Twenty guinea pigs with gentamicin-induced hearing loss were randomized equally into IGF-1 group and control group. In both groups, scala tympani fenestration was performed for injection of IGF-1 (10 microl) or artificial perilymphatic fluid (10 microl). Auditory brainstem responses (ABR) test was performed before and 7 and 14 days after surgery, respectively, and the cochlea was removed by decollation of 3 guinea pigs from each group after ABR test for observing the changes in the hair cells using scanning electron microscope. RESULTS: Significant reduction in the ABR response threshold (RT) occurred in IGF-1 group 7 and 14 days after the surgery, and on day 14, ABR RT showed significant difference between IGF-1 group and the control group. Scanning electron microscopy revealed severer damages of the hair cells in the control group, and in the IGF-1 group, finger-like microvilli was detected on the surface of the damaged hair cells. CONCLUSION: IGF-1 injection in the inner ear through the scala tympani fenestration may ameliorate the damages of the auditory function and relieve sustained toxicity of gentamicin in guinea pigs possibly by protection and partial repair of the damaged cochlea hair cells as well as protection of the afferent nerves.

[Subcloning of human neurotrophin-3 gene and construction of its genetically engineered cell model].

OBJECTIVE: To subclone human neurotrophin-3 gene (NT3) and transfer this gene into human bone marrow mesenchymal stem cells (BM-MSCs) to construct genetically engineered cells that produce NT3 in vitro. METHODS: Human BM-MSCs were cultured in low-glucose DMEM supplemented with 10% fetal bovine serum and 10 ng/ml epidermal growth factor. Flow cytometry (FCM) was used to examine the phenotypes of the cells. The eukaryotic expression vector pcDNA3.1(+)/NT3 was constructed and transferred into human BM-MSCs in vitro via liposomes. The genetically engineered BM-MSCs were selected several times with G418 and the clones were obtained and then amplified, followed by extraction of the RNA for detection of NT3 gene expression by reverse transcriptional (RT) PCR. The biological activity of the genetically engineered cells was examined by the collecting the supernatant of the culture medium for incubation of guinea pig cochlea hair cells. RESULTS: The cultured cells expressed CD13, CD29 and CD59, but no7 CD11, CD14, CD31, CD34, CD45, CD80, CD86, CD117 or HLA-DR. The BM-MSCs genetically modified with pcDNA3.1(+)/NT3 not only expressed and produced NT3, but also promoted the survival of the guinea pig cochlea hair cells in vitro. CONCLUSION: It is possible to construct the genetically engineered BM-MSCs that excrete NT3 in vitro.

[Telomere shortening in the pathogenesis of nasopharyngeal carcinoma].

OBJECTIVE: To explore the role of telomere shortening in the pathogenesis of nasopharyngeal carcinoma (NPC). METHODS: Southern blotting was employed to determine the mean telomere length (MTL) in 42 tumor samples and 15 samples of the tissues adjacent to the tumors obtained from 42 NPC patients, along with the tissue specimens from 17 patients with chronic nasopharyngitis. RESULTS: In NPC tissues, the length of the MTL was 4.5+/-2.3 kb, obviously shorter than those of the MTL in tissues adjacent to the tumor 14.6+/-2.8 kb and in chronic nasopharyngitis 15.8+/-3.1 kb. CONCLUSION: Telomere shortening may play an important role in the pathogenesis of nasopharyngeal epithelium cell malignancies.

[Two cases of ectopic thyroid tumor].

We report our experience with 2 cases of ectopic thyroid tumor and on the basis of literature review, attempting to investigate the origin, clinical manifestations, diagnosis and treatment of this disease.

Resection of nasopharyngeal angiofibroma with extranasal and extrapharyngeal involvement.

The authors report their own experiences with the diagnosis and therapy of 7 cases of nasopharyngeal angiofibroma with extranasal and extrapharyngeal involvement, thereby attempt to formulate the surgical approach for resection of huge nasopharyngeal angiofibroma with extensive involvement. The results suggested that appropriate surgical approach was of paramount importance for eliminating the tumor and may effectively reduce traumatic injury during the operation. Elective embolization of the vessels feeding the tumor could reduce bleeding and therefore increase the safety of the operation.