A comparative study of MED-EL FMT attachment to the long process of the incus in intact middle ears and its attachment to disarticulated stapes head.

The Vibrant Soundbridge© (VSB) active middle-ear implant provides an effective treatment for mild-to-severe sensorineural hearing loss in the case of normal middle ear anatomy and mixed hearing loss in middle ear malformation. The VSB floating mass transducer (FMT), with proper couplers, can be installed on various structures of the ossicular chain, e.g., the short and long process of the incus, the stapes head, and the stapes footplate. A long process (LP) coupler is most commonly used for FMT attachment to the long process of the incus with intact ossicular chain, while CliP and Bell couplers are two standardized and reliable methods for FMT attachment to the stapes head with missing incus and malleus. However, the difference and relationship of the vibration properties among these three FMT couplers remain unclear. In the present study, the stapes footplate velocity responses of the LP, CliP, and Bell couplers have been investigated in eight fresh temporal bones (TBs) to evaluate the vibration properties of these three couplers. Normal and reconstructed middle ear transfer functions (METFs) were determined from laser Doppler vibrometer (LDV) measurements. A mastoidectomy and a posterior tympanotomy were performed to expose the ossicular chain. The METFs of the normal middle ear and middle ear with LP-FMT-coupler were compared under acoustic stimulation, thus the mass effect of the FMT with LP coupler was evaluated. Additional comparisons were made between the stapes footplate vibrations of the LP-FMT-coupler (with the intact ossicular chain at the long process of the incus), CliP-FMT-coupler and Bell-FMT-coupler on the stapes head (after incus and malleus removed) under active electromechanical stimulation. After the installation of CliP-FMT-coupler and Bell-FMT-coupler to the middle ear, the average velocity amplitude of the stapes footplate, comparing to the LP-FMT-coupler, was about 15 dB higher between 1 and 6 kHz, and 10 dB lower at about 0.5 kHz. Quantitatively, there was no significant difference between the CliP-FMT-coupler and Bell-FMT-coupler. According to our study, installation of CliP-FMT-coupler or Bell-FMT-coupler on the stapes head provides considerable improvement of the middle ear mechanical and functional responses, comparing with the LP-FMT-coupler in the temporal bone experiments. Moreover, the installation of the Bell-FMT-coupler to the stapes head produces essentially the same footplate velocity responses in comparison to the CliP-FMT-coupler.

The Age-Related Orientational Changes of Human Semicircular Canals.

OBJECTIVES: Some changes are found in the labyrinth anatomy during postnatal development. Although the spatial orientation of semicircular canals was thought to be stable after birth, we investigated the age-related orientational changes of human semicircular canals during development. METHODS: We retrospectively studied the computed tomography (CT) images of both ears of 76 subjects ranged from 1 to 70 years old. They were divided into 4 groups: group A (1-6 years), group B (7-12 years), group C (13-18 years), and group D (>18 years). The anatomical landmarks of the inner ear structures were determined from CT images. Their coordinates were imported into MATLAB software for calculating the semicircular canals orientation, angles between semicircular canal planes and the jugular bulb (JB) position. Differences between age groups were analyzed using multivariate statistics. Relationships between variables were analyzed using Pearson analysis. RESULTS: The angle between the anterior semicircular canal plane and the coronal plane, and the angle between the horizontal semicircular canal plane and the coronal plane were smaller in group D than those in group A (P<0.05). The JB position, especially the anteroposterior position of right JB, correlated to the semicircular canals orientation (P<0.05). However, no statistically significant differences in the angles between ipsilateral canal planes among different age groups were found. CONCLUSION: The semicircular canals had tendencies to tilt anteriorly simultaneously as a whole with age. The JB position correlated to the spatial arrangement of semicircular canals, especially the right JB. Our calculation method helps detect developmental and pathological changes in vestibular anatomy.

Sulfur-impregnated core-shell hierarchical porous carbon for lithium-sulfur batteries.

Core-shell hierarchical porous carbon spheres (HPCs) were synthesized by a facile hydrothermal method and used as host to incorporate sulfur. The microstructure, morphology, and specific surface areas of the resultant samples have been systematically characterized. The results indicate that most of sulfur is well dispersed over the core area of HPCs after the impregnation of sulfur. Meanwhile, the shell of HPCs with void pores is serving as a retard against the dissolution of lithium polysulfides. This structure can enhance the transport of electron and lithium ions as well as alleviate the stress caused by volume change during the charge-discharge process. The as-prepared HPC-sulfur (HPC-S) composite with 65.3 wt % sulfur delivers a high specific capacity of 1397.9 mA h g(-1) at a current density of 335 mA g(-1) (0.2 C) as a cathode material for lithium-sulfur (Li-S) batteries, and the discharge capacity of the electrode could still reach 753.2 mA h g(-1) at 6700 mA g(-1) (4 C). Moreover, the composite electrode exhibited an excellent cycling capacity of 830.5 mA h g(-1) after 200 cycles.

[Screening analysis of retinopathy of prematurity and treatment of threshold retinopathy of prematurity].

OBJECTIVE: To investigate the incidence and the risk factors associated with the development of retinopathy of prematurity (ROP) by ROP screening in the premature infants and to evaluate the treatment effect of threshold ROP. METHODS: From March 2000 to December 2004, 108 premature infants with birth weight less than 2.0 kg or gestational age less than 37 weeks admitted to the Neonatal Intensive Care Unit at Guangdong Provincial People's Hospital were enrolled in the present study. They were examined with binocular indirect ophthalmoscope. The perinatal variables of the premature infants were analyzed to evaluate their correlation with the development of ROP. The infants with threshold ROP were treated with retinal photocoagulation or cryotherapy. RESULTS: The overall incidence of ROP was 21.3% (23 of 108). Among 23 premature infants with ROP, 56.5% (13 of 23) were in stage 1, 13.0% (3 of 23) in stage 2 and 30.4% (7 of 23) in stage 3. All infants with ROP stage 3 fulfilled the criteria of threshold ROP. As compared with non-ROP group, ROP infants had lower birth weight [(1.43 +/- 0.25) kg; t = 4.059, P < 0.001], shorter gestation age [(31.0 +/- 2.3) W; t = 2.637, P = 0.013], longer median time of oxygen supplementation (17 d; Z = -3.630, P < 0.001) and more demand of mechanical ventilation (chi(2) = 12.009, P = 0.001). Cases with multiple gestational births in ROP group were not significantly different from that in non-ROP group (chi(2) = 1.013, P = 0.314). Multivariate logistic regression analysis showed that low birth weight (beta = -2.542, OR = 0.079, P = 0.032) and mechanical ventilation (beta = 1.341, OR = 3.823, P = 0.025) were significantly associated with the development of ROP. In a total of seven cases with threshold ROP, six cases were treated with retinal laser photocoagulation or transscleral cryotherapy timely. After followed up for two months to two years, all treated eyes had normal pupil response to the light. The optic disk, macula and posterior retina appeared normal. No abnormal retinal vessels and proliferative vitreoretinopathy were found. One premature infant with threshold ROP, not treated by laser photocoagulation or transscleral cryotherapy, developed retinal detachment in both eyes. CONCLUSIONS: Premature infants with low birth weigh, shorter gestational age, longer history of oxygen supplemental and the using of mechanical ventilation have more chance of developing ROP. The analysis of risk factors will be helpful in understanding and prediction of development of ROP. ROP screening and timely treatment for threshold ROP are very important for preventing the development of advanced ROP in premature infants.

[The combination of positive cylinders with negative cylinders in the detection of mixed astigmatism].

OBJECTIVE: To study clinical retinoscopy combined positive cylinders with negative cylinders in the detection of mixed astigmatisms. METHOD: 189 cases (340 eyes) with mixed astigmatism were divided into three groups (< 3.00 D; 3.00 approximately 6.00 D; > 6.00 D). There are 156 eyes with mixed astigmatism less than 3.00 D (76 eyes in experiment group, 80 eyes in control group); 132 eyes with mixed astigmatism between 3.00 D to 6.00 D (68 eyes in experiment group, 64 eyes in control group) and 53 eyes with mixed astigmatism over 6.00 D (29 eyes in experiment group, 24 eyes in control group). They were examined with cycloplegic retinoscopy. Retinoscopy of combined positive cylinders with negative cylinders was applied in experiment group, while conventional retinoscopy was used in control group. According to the shape of neutralized image, the accuracy and facility of the axis judgement, operating time and the number of combined lens, the result of retinoscopy was classified into three grades. Grade I: The shape of neutralized image is well distributed. The axis is easy to be evaluated precisely. Operating time is less than five minutes and only need one or two piece of lens. Grade II: The shape of neutralized image is not so well distributed. The axis is not difficult to be evaluated. Operating time is from five to ten minutes and needs two or three piece of lens to combine with. Grade III: The shape of neutralized image is not so well distributed and would be interfered by the combined lens or other factors easily. The axis is difficult to be evaluated precisely. Operating time is more than ten minutes and needs more than three piece of lens to combine with. RESULT: In the group of mixed astigmatism less than 3.00 D, no significant difference was found between experiment group and control group. (chi(2) = 0.094, P = 0.759). However, significant difference (chi(2) = 5.546, P = 0.019) was found between the groups with mixed astigmatisms from 3.00 D to 6.00 D and very significant difference (chi(2) = 8.509, P = 0.004) was found between the groups with mixed astigmatisms over 6.00 D. CONCLUSION: Retinoscopy of combined positive cylinders with negative cylinders is an effective, convenient and precise method for detection higher degree mixed astigmatisms. It's an additional assistance for the conventional retinoscopy.

[Dry eye in graft-versus-host disease].

OBJECTIVE: To investigate patients who had ocular presentations after allogeneic hematopoietic stem cell transplantation. METHODS: The eyes of 20 patients of leukemia who had undergone allogeneic hematopoietic stem cell transplantation were examined. The ocular surface of these patients was examined by slit-lamp. The eye examination also included evaluation of tear break-up time, Schirmer tests with and without nasal stimulation, and fluorescein staining, rose bengal staining, etc. Conjunctival impression cytology and pathological examination of surgical specimens from 3 patients were performed. RESULTS: Fourteen of 20 patients developed chronic graft-versus-host disease (cGVHD). Eight patients suffered from dry eye accompanied by GVHD simultaneously. The incidence of dry eye in GVHD was 57%. Among them, 4 cases were severe dry eye associated with significant decrease of visual acuity and even development of corneal ulcer. Ophthalmic pathology findings were as follows: loss of conjunctival goblet cells or significant reduction in amount; conjunctival and corneal epithelial keratinization and squamous metaplasia; and dominance of T cell in conjunctival inflammatory infiltration cells. CONCLUSION: Dry eye is the major ocular complication after allogeneic hematopoietic stem cell transplantation. It affected the patients' life quality severely. The high incidence and potentially severe ocular problems in these patients suggest that close ophthalmic monitoring is important in allogeneic hematopoietic stem cell transplantation.