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The aim of this study was to explore the clinical features, hearing prognosis and differential diagnosis of recurrent low frequency sensorineural hearing loss （RLFD） . The clinical characteristics, clinical manifestations, audiological examination and auxiliary examination of RLFD patients were retrospectively analyzed. We summarized clinical features, draw the pure tone audiometry curves, and analyze the diagnosis of RLFD. Forty-seven patients （53 ears） with RLFD had a hearing review time of 1-124 months. The course of disease ranged from 3 to 320 months with an average course of 29 months. ①The incidence of tinnitus in the accompanying symptoms was 93.6%（44 cases）, and the ear suffocation was 83.0%（39 cases）, 38.3% （18 cases） of the patients developed vestibular symptoms during the course of the disease. ②During the observation period, 27 cases（57.4%） were diagnosed with related diseases: 7 cases（14.9%） Meniere's disease, 6 cases（12.8%） vestibular migraine, 2 cases（4.3%） with Meniere's disease and migraine, and 1 case（2.1%） with idiopathic intracranial hypotension 11 cases（23.4%） were possible cochlear migraine; ③Migraine-related RLFD had a younger onset age, more common in women; ④83.0%（44 ears）of the affected ears had stable or improved low-frequency hearing during the observation period, 17.0%（9 ears）of the affected ears experienced low-frequency hearing; ⑤18.9%（10 ears）of the affected ears had high-frequency hearing loss; ⑥RLFD had 6 types of audiological outcomes: low-frequency improvement combined with high-frequency stability; low-frequency stability combined with high-frequency stability; low frequency progress combined with high frequency stability type; low frequency improvement combined with high frequency progress type; low frequency stability combined with high frequency progress type; low frequency progress combined with high frequency progress type; ⑦Rising type hearing curve low frequency hearing prognosis is good, mountain type and descending low frequency hearing prognosis is poor. Tinnitus and ear stuffiness are the early symptoms and the most disturbing symptoms in patients with RLFD. The mechanism of Migraine may play an important role in the pathogenesis of RLFD. The rare causes such as intracranial hypotension syndrome should not be ignored. Most of the patients with RLFD had stable or improved hearing after long-term fluctuation, but some patients with low or high frequency hearing might decline. The type of initial hearing curve was a prognostic factor. Long-term hearing follow-up is helpful for prognosis evaluation.
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Objective@#The aim of this study was to explore the clinical features, hearing prognosis and differential diagnosis of recurrent low frequency sensorineural hearing loss （RLFD） . @*Method@#The clinical characteristics, clinical manifestations, audiological examination and auxiliary examination of RLFD patients were retrospectively analyzed. We summarized clinical features, draw the pure tone audiometry curves, and analyze the diagnosis of RLFD. @*Result@#Forty-seven patients （53 ears） with RLFD had a hearing review time of 1-124 months. The course of disease ranged from 3 to 320 months with an average course of 29 months. ①The incidence of tinnitus in the accompanying symptoms was 93.6%（44 cases）, and the ear suffocation was 83.0%（39 cases）, 38.3% （18 cases） of the patients developed vestibular symptoms during the course of the disease. ②During the observation period, 27 cases（57.4%） were diagnosed with related diseases: 7 cases（14.9%） Meniere's disease, 6 cases（12.8%） vestibular migraine, 2 cases（4.3%） with Meniere's disease and migraine, and 1 case（2.1%） with idiopathic intracranial hypotension 11 cases（23.4%） were possible cochlear migraine; ③Migraine-related RLFD had a younger onset age, more common in women; ④83.0%（44 ears）of the affected ears had stable or improved low-frequency hearing during the observation period, 17.0%（9 ears）of the affected ears experienced low-frequency hearing; ⑤18.9%（10 ears）of the affected ears had high-frequency hearing loss; ⑥RLFD had 6 types of audiological outcomes: low-frequency improvement combined with high-frequency stability; low-frequency stability combined with high-frequency stability; low frequency progress combined with high frequency stability type; low frequency improvement combined with high frequency progress type; low frequency stability combined with high frequency progress type; low frequency progress combined with high frequency progress type; ⑦Rising type hearing curve low frequency hearing prognosis is good, mountain type and descending low frequency hearing prognosis is poor. @*Conclusion@#Tinnitus and ear stuffiness are the early symptoms and the most disturbing symptoms in patients with RLFD. The mechanism of Migraine may play an important role in the pathogenesis of RLFD. The rare causes such as intracranial hypotension syndrome should not be ignored. Most of the patients with RLFD had stable or improved hearing after long-term fluctuation, but some patients with low or high frequency hearing might decline. The type of initial hearing curve was a prognostic factor. Long-term hearing follow-up is helpful for prognosis evaluation.
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Objective To explore the feature of embryonic communication between the carotid and vertebro-basilar system using MRA of head and neck on MR. Methods The MRA images from 7 246 consecutive patients in Liaocheng People's hospital between June 2009 and December 2015 were retrospectively reviewed. The feature of embryonic communication between internal carotid, external carotid artery and vertebro-basilar system using MRA was analyzed by two doctors. Results Forty-four cases of embryonic communication between the carotid and vertebro-basilar system were found. Thirty-nine cases of primitive trigeminal artery (PTA) and primitive trigeminal artery variants (PTAV) were detected by MRA. The prevalence of both PTA and PTAV was 0.54% (PTA, 27 cases;PTAV, 12 cases). Twenty-three cases of PTA were lateral types;four cases were medial types. All PTA originated from C4 portion of internal carotid artery, of which 27 cases connected with the basilar artery and two cases connected with the superior cerebellar artery. The region of the BA proximal to the site of convergence with the PTA was hypoplastic in seven cases and completely absent in two cases. Three cases of primitive hypoglossal artery and 2 cases of primitive proatlantal artery were detected by MRA. The prevalence of primitive hypoglossal artery and primitive proatlantal artery was 0.04% and 0.03 % respectively. Two cases of primitive hypoglossal artery were from the lateral internal carotid artery and one was from the external carotid artery. It's all on the right side. One case of primitive proatlantal artery was on the left which arises from the external carotid artery, one on the right which originated from the outer part of the internal carotid artery. Thirty-four cases were coexisted with other variants of head and neck vessels. All of the primitive hypoglossal arteries were coexisted with vertebral artery absence. One case of primitive proatlantal intersegmental artery was coexisted with vertebral artery dysplasia. Eighteen cases were associated with cerebral infarctions, and three cases with aneurysm. Conclusions MRA can accurately assess the variants of carotid-vertebasilar anastomoses and have diagnostic significance.
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Objective To analyze the efficacy and safety of tetrandrine in the adjuvant treatment of relapsed/refractory acute leukemia (except M3).Methods A total of 58 patients with relapsed/refractory acute leukemia (except M3) admitted to six tertiary hospitals in Jiangsu Province from January 2015 to December 2017 were included in this study.The tetrandrine-adjuvant standard chemotherapy regimen and standard chemotherapy regimen were given to treatment and control groups respectively.There were 17 and 41 patients in treatment and control groups.The treatment group was given tetrandrine for 5 days before the use of standard chemotherapy.The dose of tetrandrine was 4 mg ·kg-1 ·d-1,and patients had continuous oral administration of 5 days.After that,the patients in the treatment group started chemotherapy immediately.On the other side,the control group received standard chemotherapy without any other multidrug reversal medicine.Then the clinical efficacy and safety outcomes in both groups were analyzed.Results In the treatment group,5,3,and 9 cases achieved complete remission (CR),partial remission (PR),and nonremission (NR) respectively,and the total effective (CR+PR) rate was 47.06 ％ (8/17);in the control group,14,10,and 17 cases achieved CR,PR,and NR,and the total effective rate was 58.54 ％ (24/41).There was no significant difference in the total effective rate between the two groups (x2 =0.64,P =0.424).There was no significant difference in the efficacy between the two groups of patients with different genders (P ＞ 0.05).When the disease duration was 6-11 months,the difference of efficacy between the two groups was statistically significant (P =0.041).There was no significant difference in the proportion of myeloid leukemia cells,white blood cell count,platelet count,red blood cell count,and hemoglobin between the two groups before and after treatment (all P ＞ 0.05).There was no significant difference in clinical safety indicators (urine,faecal routine,liver and kidney function,and electrocardiogram) between the two groups (all P ＞ 0.05).Conclusions Tetrandrine is more effective in patients with relapsed/refractory acute leukemia (except M3) with shorter duration of disease.Compared with chemotherapy alone,the clinical efficacy of adding tetrandrine in chemotherapy cannot be considered superior to the former.
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Objective To study the effect of chloral hydrate on click sound evoked auditory brainstem re-sponse (ABR) in healthy adult guinea pig .Methods A total of 20 healthy wild type albino male guinea pigs were se-lected for ABR assessment with click sound stimulation conscious and cholral hydrate anesthesia conditions .The ABR threshold was determined according to the wave that presents highest occurrence rate under different stimulus intensity .The latency ,interpeak latency of each wave at 90 dB peSPL stimulation as well as the amplitude of waveⅡ ,Ⅲ ,Ⅳ under different stimulus intensity were recorded .Results The ABR threshold in chloral hydrate anes-thesia was 25 .50 ± 2 .76 dB peSPL and at the waking state was 28 .5 ± 3 .66 dB peSPL from control group (P>0 .05) .The latencies of each wave recorded under chloral hydrate anesthesia state were prolonged compared to those of under waking state ,wave Ⅲ ,Ⅳ and Ⅴ had significance differences (P0 .05) .The interpeak latency between wave Ⅰ - Ⅴ ,Ⅲ - Ⅳ ,Ⅳ - Ⅴ in chloral hydrate anesthesia were longer compared to those of under waking state with significant differences (P 0 .05) .The amplitude and occurrence rate of wave Ⅱwere the highest among all the waves in both experimental group and control group .The amplitude of wave Ⅱ and Ⅲ in chloral hydrate anesthesia was higher than that of the waking state under acoustic stimulation conditions ofhigh intensity(P<0 .05) while the amplitude of wave Ⅳ was lower than the waking state (P<0 .05) .Conclusion The chloral hydrate anesthesia may be able to apparently lengthen the ABR latencies of wave Ⅲ ,Ⅳ ,Ⅴ and affect the amplitude .This effect should be considered during the assessment of ABR under anesthesia state in guinea pig ;The ABR threshold of guinea pig could be determined according to the wave Ⅱ because it 's highest occurrence rate .
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Objective To study the auditory brainstem response (ABR) of normal adult CBA,C57BL,Kunming and 129 mice and analyze the ABR thresholds and latencies in order to obtain normal values and standardized testing process,thereby providing important reference for future auditory hearing research in mouse.Methods Six -week-old normal mice of CBA,C57BL,Kunming and 129(each strain containing 20 ears of 20 mice) were used in this study.ABR test with both the click and tone burst were carried on.The incidence of each wave and the thresholds and latencies of various strains of mice were recorded.Results For these four strains of mice,wave Ⅱ had the highest occurrence rate and was used to determine the thresholds.Four strains of mice all were sensitive to the sound at 8,12,16 kHz,most to 12 kHz.Under anesthesia condition,the latency of each ABR wave prolonged as testing time increase,especially the waves Ⅲ ～ V which reflected the functions of the part near the cerebral center.Conclusion Under anesthesia state,for these four strains of mice,wave Ⅱ has the highest occurrence rate and is used to determine the threshold.We determine the intensity level at which Wave Ⅱ just appeared as the ABR threshold.The stain of CBA mice is the best one to establish an animal model related to hearing function research because ABR of the other three strains are not stable as the CBA mice.Wave SP can reflect the hair cell functions indirectly.
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OBJECTIVE@#To investigate the applicability of EuroQol 5-Dimension 3-Level questionnaire (Chinese Version 1.0) (EQ-5D-3L) in the assessment of life quality of patients with idopathic sudden hearing loss.@*METHOD@#In this retrospect study, the EQ-5D-3L was assigned to 60 patients with idopathic sudden hearing loss before and after drug therapy. Audiometry examinations were undertaken and concomitant symptoms were recorded. A Wilcoxon rank sum test was applicated to the comparisons of results of EQ-5D-3L before and after the treatment, a t-test for results of EQ-VAS and a Kappa measurement for the consistency of certain dimension correlated with the symptoms.@*RESULT@#Sixty patients completed the five questions and visual analog scale of the EQ-5D. A statistically significant changes of pain/discomfort, anxiety/depression before and after the treatment were observed (P 0.05). The dimension of pain/discomfort was in agreement with the concomitant symptoms. And the result of EQ-VAS was in agreement with the therapeutic outcome.@*CONCLUSION@#It is suitable for the EQ-5D to be a general health measure with sensitivity to clinical change in idiopathic sudden sensorineural hearing loss, which monitors the patients' outcomes.
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Humans , Depression , Hearing Loss, Sensorineural , Diagnosis , Quality of Life , Self Care , Surveys and Questionnaires , Treatment Outcome , Visual Analog ScaleABSTRACT
Objective To investigate the guiding value of serum procalcitonin (PCT) level in antibiotic treatment of stroke-associated pneumonia (SAP) after spontaneous intracerebral hemorrhage. Methods A total of 120 patients with SAP after acute cerebral hemorrhage were enroled and were randomly divided into either a conventional treatment group ( n=59) or a PCT guided group ( n=61). In accordance w ith the guidelines for the use of antibiotics in China, the conventional treatment group w as treated w ith antibiotics and the course of antibiotics w as determined by the treating physician. The serum PCT of the PCT group w as monitored continuously after using antibiotics for 5 days. When PCT w as 2 w as poor outcome. They were folowed up for 6 months after discharge. A Kaplan-Meier survive curve was use to compare the survival rate of both groups. Results The course of antibiotics ( 8.95 ±2.73 d vs.13.26 ± 4.11 d;t=6.407, P<0.001) and the length of hospitalization ( 15.64 ±2.63 d vs.18.36 ±4.27 d; t=3.967, P<0.001) of the PCT group w ere significantly shorter than those of the conventional treatment group. There w ere no significant differences in the proportions of 30 d mortality ( 9.8%vs.10.1%; χ2 =0.003, P=0.951) and 90 d good outcome ( 60.6%vs.59.3%; χ2 =0.022, P=0.881) betw een the PCT guided group and the conventional treatment group. At the end of the 6-month folow-up period, a total of 13 patients (12.0%) died, including 6 in the conventional treatment group and 7 in the PCT group. The Kaplan-Meier analysis show ed that there w as no significant difference in the 6-month survival rate betw een the 2 groups (χ2 = 0.070, P= 0.791 ). Conclusions Monitoring the serum PCT level for guiding antibiotic treatment of SAP after spontaneous intracerebral hemorrhage is safe, and it may shorten the course of antibiotics and reduce the length of hospitalization.
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Objective To evaluate the value of D-dimer in assessing severity and predicting longterm prognosis in patients with community acquired pneumonia (CAP).Methods From June 2009 to December 2010,a total of 189 patients with CAP were enrolled.After admission,D-dimer,procalcitonin (PCT) and C-reactive protein (CRP) were measured,and Pneumonia Severity Index (PSI) was calculated.They were assigned into two groups according to their D-dimer levels:high D-dimer levels group (D-dimer levels≥500 μg/L) and normal D-dimer levels group (D-dimer levels ＜ 500 μg/L).The followup time was one year.A Kaplan-Meier survive curve was constructed to assess the 1-year mortality,and multivariate logistic regression analysis were used to assess the value of D-dimer for predicting long-term prognosis.Results D-dimer levels increased with increasing PSI class [class Ⅰ-Ⅲ:378.37 μg/L (216.74,649.50) μg/L; class Ⅳ:673.41 μg/L (544.77,866.85) μg/L; class Ⅴ:831.58 μg/L (591.78,1066.39) μg/L,x2 =56.58,P ＜ 0.01].The Kaplan-Meier survival curve showed that 1-year mortality rate of high D-dimer levels group was higher than normal D-dimer levels group (log-rank test,x2 =52.51,P ＜ 0.01).The multivariate logistic regression analysis showed an independent relationship between higher D-dimer levels and long-term mortality (OR =2.05,95％ CI:1.48-2.61,P ＜ 0.01).Conclusion D-dimer is an independent predictor of severity and long-term prognosis in patients with CAP.
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Objective To obtain the auditory brainstem response (ABR)wave of normal adult mice ,and to analyze the thresholds ,latency and amplitudes to provide reference for future mice auditory research .Methods To determine the thresholds according to the high occurrence rate wave of click ABR at high (90 dB SPL) ,moderate (40 dB SPL)and low(20 dB SPL)sound intensities .thresholds ,latencies and amplitudes decreased as the wave with high occurrence rate .Results The occurrence rates of wave I ,II ,III ,IV ,and V were 100% ,100% ,100% ,75% 65% at high levels ;75% ,100% ,100% ,45% ,40% at moderate levels ,and 30% ,90% ,40% ,5% ,0% at low levels ,respec-tively .The results showed wave morphology was suitable to judging thresholds :the average threshold was 20 ± 5 .62 dB SPL ,latency and amplitude ranged from 2 .71 ± 0 .17~3 .08 ± 021 ms and 6 .20 ± 2 .24~1 .63 ± 0 .85 μV ,respectively , when sound intensities changed from 90 to 20 dB SPL .Conclusion Wave II is regarded as the best wave to determine threshold latency and amplitude .It will help future researches about mice auditory under pathophysiology conditions .
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Objective Analysis of the expression of CD38,CD133 antigen and their clinical significance in myelodysplastic syndrome (MDS).Methods CD38 and CD133 antigen were analyzed by flow cytometry in 31 cases of MDS patients.Results CD38 was expressed in 18 cases (58.1% ),among them,12 cases were found to be myelodysplastic syndrome refractoryanermia ( MDS-RA ),accounting for 57.1%,6 cases were found to be MDS-RAEB,accounting for 66.7%.CD133 was expressed in 20 cases(64.5% ) ,among them,11 cases were found to be MDS-RA ( 52.4% ),1 case MDS-RAS,and 8 cases of MDS-RAEB,accounting for 88.9% .CD38 expressed significantly higher in MDS than anemia and relatively normal group ( P ＜ 0.05 ).CD133 expression in anemia groups was different from MDS-RA without statistical significance ( P ＞ 0.05 ),but was significantly different from relatively normal group (P ＜0.05).CD133 expression was significantly higher in these with MDS-RAEB than those in anemia and normal group ( P ＜ 0.05 ).Conclusions Combining with conventional antibodies,flow cytometry used in detection of CD38 ,CD133 ,could improve the diagnostic rate of MDS.
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Objective To investigate the clinical significance of flow cytometry (FCM) assay in following up of the minimal residual disease (MRD) used for predicting relapse and guiding chemotherapy. Methods The clinical data of 43 acute leukemia patients diagnosed by MIC were collected in our hospital from 2005 July to 2008 June.Bone marrow aspirates were collected from 43 patients with newly diagnosed acute leukemia after induction therapy and during constimulation therapy. The cells with leukemia associated with immunophenotype were investigated using FCM, as immunologic target of MRD. Results MRD were detected earlier in predicting the relapse than those of the traditional bone marrow cells morphology assay by an average of 4-6 months. The results of the MRD following up: MRD was negative at CR in 26 cases, 6 cases relapse, 20 cases of them were kept negative during following up. MRD was positive in 17 cases at CR, 9 cases of them were relapse. 4 cases after intensified chemotherapy the MRD became negative and kept egative for more than one year. The MRD of the 43 cases at CR were divided into 3 groups, MRD less than 1×10-4 group (A group) MRD between 5×10-3 and 1×10-4 group (B group) and MRD above 5×10-3 group(C group). By chi square test. There was no statistical significance between A group and B group, but there was tatistical significance between B group and C group (P=0.02). Conclusion The application of FCM in detecting MRD has important clinical significance in predicting relapse and guiding chemotherapy.
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BACKGROUND: Frenulum of prepuce of penis contained many nerve terminals is an extremely sensitive region. If the frenulum is injured in circumcision or other operations, the complication, such as postoperative spontaneous pain of penis, sexual disturbance and so on, will occur. But there still is no define explanation for this up to now.OBJECTIVE: To observe the distribution of immunoreactive nerve terminal of calcitonin gene-related peptide (CGRP) in prepuce of penis and frenulum of prepuce of adult SD rats, and look for the source of CGRP immunoreactive nerve terminal in frenulum of prepuce.DESIGN: A single sample trial.SETTING:Department of Anatomy, School of Medicine, Zhejiang University.MATERIALS: The experiment was performed at Department of Anatomy,School of Medicine. Zhejiang University from September 2004 to May 2005. A total of 20 adult male SD rats were selected, and were raised in warm, quiet, photophygous environment for 1 week before the trial so as to make the rats fit for the environment and maintain their basal state.METHODS: The rats were assigned randomly into 2 groups. Ten rats in the first group were treated with the immunohistochemical method to observe the distribution of CGRP immunoreactive nerve terminal in prepuce of penis and frenulum of prepuce of adult rats. Ten rats in the second group were treated with fluorogold (FG) retrograde labeled combined with CGRP immunofluorescence labeled method to look for the source of CGRP immunoreactive nerve terminal in frenulum of prepuce of penis. MAIN OUTCOME MEASURES: ①The morphology and distribution of CGRP immunoreactive nerve terminal in prepuee of penis and frenulum of prepuce of adult SD rats were observed under light microscope. ②The distributive density and difference of CGRP immunoreactive nerve terminal in prepuce of penis and frenulum of prepuce were detected and compared (represented by A). ③Morphology and distribution of FG retrograde labeled -positive, CGRP single-labeled positive and FG/CGRP double-labeled positive neurons in dorsal root ganglion were observe under fluorescence microscope. ④Mean quantity of FG retrograde labeled positive, CGRP single abeled positive and FG/CGRP double-labeled positive neurons in dorsal root ganglion was counted.RESULTS: Totally 20 rats were involved in the analysis of results. ① Amber-coloured CGRP immunoreactive nerve terminal appeared in prepuce of penis and frenulum of prepuce of adult rats. These nerve terminal mainly occurred in basal layer of epidermis and papillary layer of dermis, distributed as twig shape or intestiniform; mostly of them were bundled, different in length, and some of them showed enlarged nodosity. ②The distributive density of CGRP immunoreactive nerve terminal in frenulum of prepuce of penis was significantly larger than that in prepuce of penis (2.15±0.32, 1.02±0.22,t =-2.03,P＜0.01). ③Combined with the FG retrograde labeled method it was found that these nerve terminal was derived from neurons of dorsal root ganglion opposed to the sixth lumbar spinal cord and the neurons of dorsal root ganglion opposed to the first acral spinal cord. FG retrograde labeled positive neurons differed in length. The cell body showed round or orbicular-ovate, without obvious prominence. Bright inaurate fine particle appeared in cytoplasm, no label in nucleus. Most cells arranged in line along nerve tract or diffusedly distributed. Most CGRP single-labeled positive neurons were middle or small cells found by CGRP immunofluorescence labeling. Dyeing was too dark.Reaction product distributed evenly in cytoplasm, which showed bright dark green (FITC labeled color). The same positive section was observed comparatively under different excitation light. It was found that FG/CGRP double-labeled positive cells were middle or small, and its amount accounted for a half of the total number of FG retrograde positive cells.CONCLUSION: CGRP may participate the transmission of sensory information in prepuce of penis and frenulum of prepuce of rats. The CGRP immunoreactive nerve terminal in frenulum of prepuce of penis of rats is sourced from neurons of dorsal root ganglion opposed to the sixth lumbar spinal cord and the neurons of dorsal root ganglion opposed to the first sacral spinal cord.
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<p><b>OBJECTIVE</b>To investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss.</p><p><b>METHODS</b>Forty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca(2+)-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE + CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE + NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope.</p><p><b>RESULTS</b>The CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92 +/- 2.90 dB and 59.30 +/- 3.95 dB in group 2. There were significant differences (P < 0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P < 0.01). Stereocilia of 89 OHC(3) were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC(2),3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion.</p><p><b>CONCLUSIONS</b>Low calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.</p>