Endoscopic Third Ventriculostomy for Non-Tumor Obstructive Hydrocephalus in Children under Two Years of Age

The goal of this work is to report on the efficacy of endoscopic third ventriculostomy (ETV) for non-tumor obstructive hydrocephalus in children aged two years and below. In the period between June 2007 and December 2014, we had performed ETV in 30 patients with hydrocephalus from diverse etiologies. Among them were eight children aged two years or below. Clinical, radiological and outcome data of these children were retrospectively reviewed to assess ETV efficiency in this age group. Eight children (6 boys, 2 girls) with age range from 6 to 24 months (mean 12.5 months, median 15 months) suffering from non-tumor obstructive hydrocephalus underwent ETV as primary treatment. Seven patients (87.5%) were under two years and 3 had less than one year of age at the time of surgery. Macro crania, suture diastasis, scalp vein bulging and sunset gaze were the most common findings on physical examination. Computed tomography scanning was done in all patients but none had magnetic resonance imaging. Hydrocephalus was due to primary (congenital) aqueductal stenosis in all cases and was associated with myelomeningocele in one. ETV was successful in 7 (87.50%) cases but failed in one. Operation time varied from 28 to 35 minutes (mean 31.12 minutes, median 31.5 minutes). No intraoperative complication occurred. The child in whom ETV failed had postoperative CSF leak. No death related to procedure occurred. Hospital stay ranged from 2 to 4 days (mean, 2.87 days, median, 3 days). Follow up range was 5.5 to 86 months (0.46 to 7.16 years);mean, 59.14 months (4.92 years);median, 45.75 months (3.81 years).

Numerical simulation of dynamic characteristics of a cable-stayed aqueduct bridge

In this paper, a full-scale 3-D finite element model of the Jundushan cable-stayed aqueduct bridge is established with ANSYS Code. The shell, fluid, tension-only spar and beam elements are used for modeling the aqueduct deck, filled water, cables and support towers, respectively. A multi-element cable formulation is introduced to simulate the cable vibration. The dry （without water） and wet （with water） modes of the aqueduct bridge are both extracted and investigated in detail. The dry modes of the aqueduct bridge are basically similar to those of highway cable-stayed bridges. A dry mode may correspond to two types of wet modes, which are called the in-phase （with lower frequency） and out-of-phase （with higher frequency） modes. When the water-structure system vibrates in the in-phase/out-of-phase modes, the aqueduct deck moves and water sloshes in the same/opposite phase-angle, and the sloshing water may take different surface-wave modes. The wet modes of the system reflect the properties of interaction among the deck, towers, cables and water. The in-phase wet frequency generally decreases as the water depth increases, and the out-of-phase wet frequency may increase or decrease as the water depth increases.

Optimizing CT for the evaluation of vestibular aqueduct enlargement:Inter-rater reproducibility and predictive value of reformatted CT measurements

Enlarged vestibular aqueduct(EVA), the most frequent identifiable cause of congenital hearing loss, is evaluated with high-definition multidetector CT in the axial plane. Our purpose was to determine which reformatted CT measurements are most reproducible. Seven multiplanar reformatted images were created for each of the 64 temporal bones in patients with EVA. Intraclass correlation coefficients(ICC) were used to assess inter-observer variability, and both linear regression and ROC analyses were used to compare the measurements with severity of hearing loss, as assessed by pure tone audiometry. All seven measurements had excellent inter-observer variability, with average-measure ICC ranging from 0.92 to 0.98. There was no statistically significant correlation between the radiologic degree of aqueduct enlargement and severity of hearing loss using any of the seven measurements; ROC analyses revealed areas under the curves ranging from 0.57 to 0.73. Optimal accuracy was obtained with a threshold of 1.75 mm as measured at the aqueductal aperture in the P€oschl plane, with sensitivity of 0.75 and specificity of0.63. Although the radiologic measurement may not serve as a reliable tool for assessing severity of EVA, P€oschl plane reformatting has proven to be better than conventional axial acquisition plane for identifying patients with clinically significant hearing loss.

SLC26A4 mutation testing for hearing loss associated with enlargement of the vestibular aqueduct

Pendred syndrome(PS) is characterized by autosomal recessive inheritance of goiter associated with a defect of iodide organification, hearing loss, enlargement of the vestibular aqueduct(EVA), and mutations of the SLC26A4 gene. However, not all EVA patients have PSor SLC26A4 mutations. Two mutant alleles of SLC26A4 are detected in 1/4 of North American or European EVA populations, one mutant allele is detected in another 1/4 of patient populations, and no mutations are detected in the other 1/2. The presence of two mutant alleles of SLC26A4 is associated with abnormal iodide organification, increased thyroid gland volume, increased severity of hearing loss, and bilateral EVA. The presence of a single mutant allele of SLC26A4 is associated with normal iodide organification, normal thyroid gland volume, less severe hearing loss and either bilateral or unilateral EVA. When other underlying correlations are accounted for, the presence of a cochlear malformation or the size of EVA does not have an effect on hearing thresholds. This is consistent with observations of an Slc26a4 mutant mouse model of EVA in which hearing loss is independent of endolymphatic hydrops or inner ear malformations. Segregation analyses of EVA in families suggest that the patients carrying one mutant allele of SLC26A4 have a second, undetected mutant allele of SLC26A4, and the probability of a sibling having EVA is consistent with its segregation as an autosomal recessive trait. Patients without any mutations are an etiologically heterogeneous group in which siblings have a lower probability of having EVA. SLC26A4 mutation testing can provide prognostic information to guide clinical surveillance and management, as well as the probability of EVA affecting a sibling.

The genetic load for hereditary hearing impairment in Chinese population and its clinical implication

Objective To understand the genetic load in the Chinese population for improvement in diagnosis, prevention and rehabilitation of deafness. Methods DNA samples, immortalized cell lines as well as detailed clinical and audiometric data were collected through a national genetic resources collecting network. Two conventional genetic approaches were used in the studies. Linkage analysis in X chromosome and autosomes with microsatellite markers were performed in large families for gene mapping and positional cloning of novel genes. Candidate gene approach was used for screening the mtDNA 12SrRNA, GJB2 and SLC26A4 mutations in population -based samples. Results A total of 2,572 Chinese hearing loss families or sporadic cases were characterized in the reported studies, including seven X-linked, one Y-linked, 28 large and multiplex autosomal dominant hearing loss families, 607 simplex autosomal recessive hereditary hearing loss families, 100 mitochondrial inheritance families, 147 GJB2 induced hearing loss cases, 230 cases with enlarged vestibular aqueduct (EVA) syndrome, 169 sporadic cases with auditory neuropathy, and 1,283 sporadic sensorineural hearing loss cases. Through linkage analysis or sequence analysis, two X-linked families were found transmitting two novel mutations in the POU3F4 gene, while another X -linked family was mapped onto a novel locus, nominated as AUNX1 (auditory neuropathy, X-linked locus 1). The only Y-linked family was mapped onto the DFNY1 locus(Y-linked locus 1, DFNY1). Eight of the 28 autosomal dominant families were linked to various autosomal loci. In population genetics studies, 2,567 familial cases and sporadic patients were subjected to mutation screening for three common hearing loss genes: mtDNA 12S rRNA 1555G, GJB2 and SLC26A4. The auditory neuropathy cases in our samples were screened for OTOF gene mutations. Conclusions These data show that the Chinese population has a genetic load on hereditary hearing loss. Establishing personalized surveillance and prevention models for hearing loss based on genetic research will provide the opportunity to decrease the prevalence of deafness in the Chinese population.

Transverse seismic response of beam aque-duct considering fluid-structure coupling

Based on the theory of Housner, the transverse seismic response of beam aqueduct considering fluid-structure coupling is established. With the variation of aqueduct cross-section ratio of depth to width, the aqueduct transverse seismic response change. The transverse seismic response of a large-scale aqueduct in several work condition are calculated. It shows that the transverse seismic response is greatly influenced by the water mass in the aqueduct, but the shaking water play a TLD role. ff the whole water is appended aqueduct body, it will magnify seismic inertia action. When aqueduct cross-section is selected, the influence of ratio of depth and width to pier seismic response should be considered in order to reduce seismic action.

颞骨畸形和非综合征性耳聋SLC26A4基因

先天性颞骨畸形（主要为大前庭水管综合征）所致耳聋是儿童感音神经性聋的常见原因，与SLC26A4基因突变有密切关系。SLC26A4基因突变的临床特点和发生频率在不同国家、地区、不同种族之间有很大的差异。本文就SLC26A4基因及其突变热点的分子流行病学研究情况做一综述。

大前庭导水管综合征早期诊断的价值

大前庭水管综合征（large vestibular aqueduct syndrome,LVAS）是一种很有临床特点的先天性致聋性疾病,是一种以渐进性、波动性听力下降为主要特征的感音神经性听力损失,早在20世纪70年代末就被Valvassori定义为一种由于内耳畸形所致的听力障碍[1],而国内对这一疾病的认识开始于20世纪90年代初期。近年随着全社会对听力保健关注度的增加和相关基础研究的深入,

Relationship between the external aperture and hearing loss in large vestibular aqueduct syndrome

Backgroud Large vestibular aqueduct syndrome （LVAS） is a major cause of hearing loss in childhood. This study aimed at measuring external aperture of enlargement of the vestibular aqueduct （EVA） and analyzing relationship between the size of external aperture and hearing loss. Methods Diagnostic criteria of LVAS were based on hearing loss and CT images. CT images of temporal bone of 100 LVAS patients were collected and 60 control subjects were reviewed retrospectively in the past 10 years. A battery of audiometric and vestibular function tests were performed. The width of the vestibular aqueduct （VA） was measured on axial CT images of the temporal bone. Results One hundred patients （65 men, 35 women） were diagnosed as having the isolated EVA. Hearing loss mostly occurred in early childhood. The diagnosis age of LVAS was 7.7 years on average. The causes of hearing loss could not be confirmed by initial consult. Typically, audiometric curve is the high-frequency down-sloping configuration. 92% of the cases had severe or profound sonsorineural hearing loss （SNHL）. The mean size of the external aperture was （7.5±1.2） mm in present LVAS. Statistical analysis showed that the degree of hearing loss is unrelated to the width of VA. Conclusions LVAS is a distinct clinical entity characterized by fluctuating, progressive SNHL. The degree of hearing loss is unrelated to the size of external aperture of VA. The protective management and hearing aid have become the main therapies. The cochlear implantation might be performed if the hearing loss affected learning at school.

大前庭水管综合征研究进展

大前庭水管综合征（large vestibular aqueduct syndrome, LVAS）为SLC26A4基因造成的隐性遗传性听力障碍疾病。影像学可表现为前庭导水管扩大，而临床表现可为波动性听力减退，个别伴耳鸣及眩晕等。近年来，听力学检查统计多显示混合性聋。虽有许多已知研究报道，但LVAS的发病基础、生理改变等仍无确切定论，而至今仍未有一确切治疗手段可治愈甚至预防该病。本文就LVAS的解剖基础、病因、发病基础、诊断、检查及治疗进行综述。

Ceftriaxone-induced immune hemolytic anemia in a case with large vestibular aqueduct syndrome after cochlear implant

To the Editor:Drug-induced immune hemolytic anemia (DIIHA)is a rare but severe condition.Ceftriaxone,a third-generation cephalosporin with a wide antibacterial spectrum and effective antibacterial action,is one of the most common drugs causing DIIHA.^[1]Ceftriaxoneinduced immune hemolytic anemia (CIIHA)is a potentially fatal complication.^[2]Most of the patients were children.The reported fatality rate of CIIHA was as high as 40%.

STUDY ON THE EROSION RATE OF POWDERED ACTIVATED CARBON IN RAW WATER AQUEDUCT

Growing interest in using Powdered Activated Carbon （PAC） in raw water aqueduct, as a method of polluted surface water treatment, raises the question of transport of PAC in the aqueduct, which is related to the potential PAC erosion along the aqueduct. By means of a recently developed re-circulating flume, erosion rates of PAC with the grain size of 230 meshes （less than 62μm） depending on shear stress and bulk density were the discussed with real-time measurement of suspended PAC concentration. Lateral cross sectional averaging shear stress was decided by the actual value in the raw water conveying aqueduct of upstream Huangpu River, Shanghai, China, smaller than 1.8 N＇m 2. As for the bulk density, it was measured with compacting times varying from 1 d to 15 d, equivalent to 1 550 kg/m3-1 800 kg/m3. Experiments were conducted for the shear stress and bulk density separately, so as to isolate and quantify the effects of one of the parameters. The results demonstrate that, for a particular PAC particle, the erosion rate increases with shear stress and decreases with bulk density as a function of power form. A product of powers of the lateral cross sectional averaging shear stress and bulk density to estimate PAC erosion rate is presented by approximating experimental data sets.

Molecular basis of hearing loss associated with enlarged vestibular aqueduct

Enlarged vestibular aqueduct(EVA)is a radiologic malformation of the inner ear most commonly seen in children with sensorineural hearing loss.Most cases of EVA with hearing loss are caused by biallelic mutations of SLC26A4.In this review,we discuss the potential mechanisms underlying the pathogenesis of hearing loss with EVA due to malfunction of SLC26A4,the detection rates of SLC26A4 mutations in EVA patients from different populations,and the role of other genetic factors(eg,mutations in FOXI1 and KCNJ10)as etiologic contributors to EVA.Elucidating the molecular etiology of EVA-associated hearing loss may facilitate genetic counseling and lead to potential therapeutic strategies.