Preparation and performance of a pH-sensitive cisplatin-loaded magnetic nanomedicine that targets tumor cells via folate receptor mediation.

The present study aimed to prepare cisplatin (CDDP)-loaded magnetic nanoparticles (MNPs), which target folate receptors via a pH-sensitive release system (FA­PEG­NH­N=MNPs­CDDP). This is of interest for the development of intelligent drug delivery systems that target tumors of the head and neck. The chemical coprecipitation method was used to prepare ferroferric oxide MNPs. These were modified with aldehyde sodium alginate complexed with the chemotherapeutic agent, CDDP on the surface of the nanoparticles. Double hydrazine­poly(ethylene glycol; PEG) was also prepared by attaching the carboxyl group of hydrazine­folate on one side of the double hydrazine­PEG, obtaining folate­hydrazine­PEG­diazenyl. This binds the aldehyde group of sodium alginic acid on the MNP to enclose CDDP, in order that it is sequestered within the carrier. This method obtained a pH­sensitive, FA­modified CDDP­loaded MNP (FA­PEG­NH­N=MNPs­CDDP), which acts as an intelligent tumor targeting drug delivery system. The mean size of the MNPs was ~10.2±1.5 nm, the mean hydrodynamic diameter detected by laser particle sizing instruments was 176.6±1.1 nm, and the ζ­potential was ­20.91±1.76 mV. The CDDP content was 0.773 mg/ml, the iron content was ~1.908 mg/ml and the maximum saturation magnetization was 16.3±0.2 emu/g. The current study produced a pH­sensitive FA­modified CDDP­loaded MNP that is stable and exhibits magnetic responsiveness, which releases CDDP in a low pH environment.

[Development of a hydrophilic anti-fogging agent for nasal endoscopy].

OBJECTIVE: To develop a transparent, non-toxic, non-irritating anti-fogging agent with long-lasting effect for nasal endoscopy. METHODS: The anti-fogging agent was prepared by mixing ethanol, propylene glycol, polyoxyethylene lauryl ether, sodium dodecyl sulfate, polyethylene glycol 400 and deionized water at different proportions based on an orthogonal test design. Twenty-seven test samples of the anti-fogging agents were obtained, which were colorless, transparent, and non-irritating, with a pH value of 7-8. Storz00 nasal endoscopy and its imaging system were used to test the anti-fogging time of the 27 samples, and each agent was tested for 3 times with medical Seoul iodine and 95% ethanol as control. RESULTS: The optimal composition of the anti-fogging agent was 20% ethanol, 10% propylene glycol, 20% polyoxyethylene lauryl ether, 4% sodium dodecyl sulfate, 4% polyethylene glycol, 42% deionized water. The anti-fogging time of this agent reached 15 min, significantly longer than that of medical Seoul iodine (4 min) and 95% ethanol (18 s). CONCLUSION: This anti-fogging agent for nasal endoscopes is colorless and safe and has a long anti-fogging time by forming a homogenous transparent membrane over the endoscopic lens.

[Cochlear implant in patients with congenital malformation of the inner ear].

OBJECTIVE: To summarize the clinical experience with multi-channel cochlear implantation in patients with inner ear malformations and evaluate and the outcomes of speech rehabilitation. METHODS: A retrospective study was conducted in 295 patients receiving cochlear implantation from 1998 to 2007, including 25 patients with large vestibular aqueduct syndrome (LVAS), 9 with Modini malformation, and 5 with common cavity deformity. All the patients received the Nucleus24 cochlear implants. In LVAS cases, 4 had Nucleus 24R (ST) implants, 8 had Contuor implants, 10 had Contuor Advance, and the remaining cases used Nucleus24(M) straight-electrode implants. RESULTS: Severe gusher appeared in 3 cases of LVAS, and perilymph fluctuation were seen in other 15 cases. Four patients with Mondini malformation and 2 with common cavity malformation also experienced severe gusher, but the electrodes were inserted smoothly in all the patients without postoperative facial paralysis or cerebrospinal fluid leakage. The hearing threshold in these patients was similar to that in patients with normal cochlear structure. After speech rehabilitation for over 6 months, the abilities of speech discrimination and spoken language improved in all the cases in comparison with the preoperative lingual functions. CONCLUSION: Multi-channel cochlear implantation can be performed in patients with inner ear malformation, but should not be attempted in patients with poor cochlear and cochlear nerve development. A comprehensive pre-operative radiographic and audiological evaluation is essential.

[Cochlear implantation in patients with large vestibular aqueduct syndrome].

OBJECTIVE: To evaluate the hearing and speech recognition in patients with large vestibular aqueduct syndrome undergoing multi-channel cochlear implantation. METHODS: From 2005 to 2008, multi-channel cochlear implantation surgeries were performed in 22 patients with large vestibular aqueduct syndrome. All the patients received multi-channel cochlear implantation through transmastoid facial recess approach. The postoperative outcomes of the patients were compared with those of 22 patients with non-malformed cochlear. RESULTS: Severe gusher occurred in 3 cases during the implantation, and perilymph fluctuation was found in another 15 cases, with a rate of anomalies of 81.8%. All the electrodes were totally inserted into the cochlear, and no facial paralysis or cerebrospinal fluid leakage occurred after the operation. The hearing threshold in these patients was similar to that in patients with normal cochlear receiving the implantation. After speech rehabilitation for over 6 months, all the patients showed improved hearing and verbal ability. CONCLUSION: Multi-channel cochlear implantation can be performed in patients with large vestibular aqueduct syndrome, but preoperative hearing assessment and radiographic examinations should be performed.

[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.

[Audiological assessment in 88 patients with otosclerosis].

OBJECTIVE: To analyze the clinical data of the hearing in otosclerosis patients and explore their association with the clinical manifestations. METHOD: A retrospective analysis of 88 otosclerosis cases (162 ears) was performed. Pure tone audiometry was performed in all the cases 1 to 3 days before the operation for speech analysis at the frequencies of 500, 1 k, 2 kHz and to determined the average pure-tone hearing threshold (PTA) and gas Bone gap (ABG). The incidence of carhart notch was observed in patients with simple conductive hearing loss and mixed hearing loss, and in the early, middle and late stage of otosclerosis. RESULTS: Carhart notch occurred at significant higher incidence in patients with simple conductive hearing loss and in early otosclerosis (P<0.05). CONCLUSION: For common otosclerosis, the lesion invades initially the vestibular window, round ligament and stapes floor, followed by the base of the cochlea, and therefore observation of the carhart notch may help determine the disease course.

[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.

[Establishment of tympanosclerosis by intratympanic injection of Staphylococcus aureus in guinea pigs].

OBJECTIVE: To establish a guinea pig model of tympanosclerosis and investigate the development and progression of tympanosclerosis in the tympanic membranes and middle ear mucosa. METHODS: Twenty-one healthy guinea pigs were subjected inoculation of 1x10(8)/L Staphylococcus aureus into the left middle ear cavities under general anaesthesia, with the right ears as the control, to establish models of chronic purulent otitis media. The animals were sacrificed by decapitation after 1, 3 and 6 months after model establishment for histological examination of the middle ear mucosa. RESULTS: The histological changes of tympanosclerosis occurred in some of the animals 3 months after model establishment, and the extent of calcium deposition and fibrosis across the mucosa were positively correlated with the duration of chronic purulent otitis media. CONCLUSION: Tympanosclerosis may occur in some guinea pigs after inoculation of Staphylococcus aureus into the middle ear cavity, and this model can be useful for study of tympanosclerosis.

[Audiological assessment in 79 patients with tympanosclerosis].

OBJECTIVE: To conduct audiological assessment in patients with tympanosclerosis. METHODS: A retrospective review was conducted in 79 patients with tympanosclerosis (involving 79 ears) with complete records, including 30 patients (30 ears) with fixed Malleus-incus complex, 29 (29 ears) with fixed stapes, and 20 (20 ears) with fixations of both the stapes footplate and the Malleus-incus complex. Audiometry was performed for all the patients one or two days before operation, and the audiological features of the patients were compared between the 3 groups. RESULTS: Most of the patients (65.8%) suffered conductive hearing loss, 32.9% had mixed deafness, and one patient had sensorineural hearing loss. No statistically significant differences was noted in the speech frequency (0.5, 1, and 2 kHz) air conduction pure tone average (PTA) or the air-bone gap (ABG) in the 3 groups (P<0.05). CONCLUSION: Most of the patients with tympanosclerosis suffer conductive hearing loss, and the severity of hearing loss is not associated with the site of tympanosclerosis.

[Effects of ossicular reconstruction with partial ossicular replacement prosthesis in patients with tympanosclerosis].

OBJECTIVE: To evaluate the effect of ossicular reconstruction with partial ossicular replacement prosthesis (PORP) in patients with tympanosclerosis. METHODS: The data of 28 cases of tympanosclerosis treated between 1992 and 2006 were reviewed. Of the 28 patients, 14 (14 ears) underwent ossicular reconstruction with PORP and 14 (14 ears) had ossicular mobilization, and all the patients were followed-up for 3-24 months. RESULTS: Significant improvement was found in postoperative speech frequency (500, 1000, 2000 Hz) pure tone average (PTA) and air-bone gap (ABG) closure after in the operation the two groups. Ossicular reconstruction using PORP resulted in statistically better ABG closure and PTA (P<0.05). CONCLUSION: In ossicular attic fixation, ossicular reconstruction using PORP can yield better results than mobilization of the major ossicles in patients with tympanosclerosis.