Assessment of mastoid air cell size versus sigmoid sinus variables with a tomography-assisted digital image processing program and morphometry

We assessed the mastoid air cell size and variables of the sigmoid sinus in healthy ears and ears with chronic otitis media (COM). Thirty-eight patients with unilateral COM [15 with cholesteatoma (COM/+) and 23 without cholesteatoma (COM/–)], and 20 subjects with healthy ears, were included in the study. Assessment was performed using a quantitative digital image processing computed tomography (CT) program, and the volume of the mastoid bone was measured using the morphometric method of Cavalieri. In both COM/+ and COM/– patients the sigmoid to suprameatal spine distance and mastoid size were greater on the healthy side than on the diseased side (p<0.05). The distance and area were significantly greater in the healthy control subjects than in either the healthy or the diseased ears of the patients with COM (p<0.05). In the healthy ears of COM patients, there was significant correlation between the sigmoid to suprameatal spine distance and air cell size and mastoid volume (p<0.05). In the diseased ears of COM patients, this correlation was absent (p>0.05). The sigmoid sinus shape was of the half-moon type (62%), protrusive type (22%) and saucer type (16%). The digital image processing CT program allowed us to estimate the individual area of the air and soft tissue filled mastoid air cells. The mastoid size in both intact and disease ears of COM patients was smaller than in the healthy controls. The mastoid size may be determined genetically. However, environmental factors such as infection may also affect the mastoid size. Therefore, both genetic and environmental factors may be related to COM as far as the size of the mastoid air cells is concerned.     

单侧慢性化脓性中耳炎颞骨CT解剖学研究

目的 研究单侧慢性化脓性中耳炎颞骨CT解剖学特征及其临床意义。 方法 回顾性分析35例单侧非胆脂瘤型慢性化脓性中耳炎患侧颞骨（病例组）与健侧颞骨（对照组）CT影像资料，比较两组咽鼓管外耳道角、岩枕角、乳突窦入口直径、咽鼓管骨部直径、咽鼓管骨部长度、咽鼓管骨部最大径与咽鼓管骨部长度之比，及乳突气化程度（良好、差）等解剖参数。 结果 患侧咽鼓管外耳道角、岩枕角分别是（137.4 ± 8.1）°、（52.5 ± 3.8）°，乳突窦入口直径、咽鼓管骨部最大径分别是（0.29±0.08）cm、（0.18±0.07）cm，咽鼓管骨部长度为（1.07±0.15）cm，咽鼓管骨部最大径与骨部长度之比为（17.1±5.4）%；健侧咽鼓管外耳道角、岩枕角分别是（138.3±7.7）°、（53.1±4.3）°，乳突窦入口直径、咽鼓管骨部最大径分别是（0.35±0.07）cm、（0.21±0.07）cm，咽鼓管骨部长度为（1.17±0.17）cm，骨部最大径与骨部长度之比为（20.9±14.3）%。患侧乳突窦入口直径、咽鼓管骨部最大径、咽鼓管骨部长度较健侧小，差异具有统计学意义（t = 4.37、3.09、－3.17，P<0.05）。患侧乳突气化较健侧差，差异具有统计学意义（χ2 = 6.34，P<0.05）。患侧与健侧咽鼓管外耳道角、岩枕角及咽鼓管骨部最大径与咽鼓管骨部长度之比差异无统计学意义（P>0.05）。 结论 单侧慢性化脓性中耳炎患侧颞骨存在解剖变异。咽鼓管骨部小、乳突气化差及乳突窦入口狭窄与单侧慢性化脓性中耳炎相关。     

Posterior tympanotomy is a riskier procedure in chronic otitis media than in a normal mastoid: a high-resolution computed tomography study

Purpose

The aim of our study was to compare the difficulty in performing a posterior tympanotomy in chronic otitis media (COM) versus the same procedure in a normal mastoid.

Materials and methods

The study included 122 patients who underwent tympanomastoidectomy for unilateral chronic otitis media with contralateral normal mastoid pneumatization. We evaluated the anatomical relationships between the mastoid segment and neighboring structures by analyzing axial temporal bone computed tomography scans. A vertical line (line A) was drawn tangential to the most lateral end of the posterior semicircular canal (point A). Three distances were measured: the distance (D1) between the point A and the most lateral end of the mastoid segment of the facial nerve (point B), the distance (D2) between the line A and the point B, and the distance (D3) between the point B and the posterior end of the bony annulus of the external auditory canal.

Results

The average measurements of D1 and D3 were 3.79 ± 0.55 and 2.63 ± 0.51 mm, respectively, in the normal mastoid ears and 3.47 ± 0.59 and 2.35 ± 0.44 mm, respectively, in the COM ears. The measurements of D1 and D3 were statistically shorter in the COM ears than in the normal ears.

Conclusions

These findings suggest that the facial recess in COM may be narrower than in a normal mastoid and that performing a posterior tympanotomy may be riskier in COM than in a normal mastoid due to the potential for injury to the neighboring structures and the facial nerve.

     

The distance of the sigmoid sinus and the middle fossa dura from the external auditory canal in chronic otitis media

Purpose

Mastoid pneumatization is reduced in most patients suffering from chronic otitis media (COM). In most studies, the relationship between the degree of pneumatization and the distance of the sigmoid sinus from the external auditory canal has been examined, yielding different results. This study addresses the relationship between COM and the distance of the sigmoid sinus and also middle fossa dura from the external auditory canal.

Methods

This was a case–control study on 15 adult COM patients, 12 traumatic facial palsy patients, and 15 cadaver temporal bones. After mastoidectomy, the distance between the spine of Henle and both the middle fossa dura and sigmoid sinus were measured, and the findings in each group was analyzed using Tukey’s and ANOVA tests.

Results

The average distance of the external auditory canal and the sigmoid sinus was 15.27 ± 3.3 mm in the COM group, 16.92 ± 3.23 mm in the traumatic facial palsy group, and 14.53 ± 2.92 mm in the cadaver temporal bones. There was no significant difference between the groups (p = 0.115). The average distance of the spine of Henle from the middle fossa dura was 6.73 ± 1.62 mm in the COM group, 11.4 ± 2.05 mm in the traumatic facial palsy group, and 8.93 ± 1.94 in the cadaver temporal bones. There was a significant difference between the groups (p < 0.001).

Conclusion

The distance of both the sigmoid sinus and the middle fossa dura from the external auditory canal (which indicates mastoid pneumatization) is reduced in COM patients.     

Analysis of unilateral sclerotic temporal bone: how does the sclerosis change the mastoid pneumatization morphologically in the temporal bone?

Backgrounds Some disorders, such as otitis media and Eustachian tube dysfunction, may cause the temporal bone to become sclerotic. A sclerotic temporal bone has the tendency to shrink. The aim of this study was to evaluate the morphologic changes that result from sclerosis of the temporal bone. Methods We measured 9 variables on 2 axial images, and 8 variables on 2 coronal images in healthy ears and diseased ears in 37 patients with unilateral chronic otitis media. We also measured the volume of mastoid pneumatization. Results The distance from sigmoid sinus to Henle’s spine was correlated to the degree of volume reduction, and it accounted for about 17.7% of the total variation in volume reduction. There was no difference in the sigmoid sinus type in comparisons between sclerotic and pneumatic mastoids. Conclusions The sclerosis of the temporal bone was observed to reduce the volume of the mastoid pneumatization. However, a large portion of the volume reduction may result from the sclerotic change in the air cell system, rather than from shrinkage of the mastoid bone. Therefore, the location of surgically-important structures, in the middle and inner ear, is only rarely changed in sclerotic temporal bone. Presented as a poster titled as “analysis of morphologic changes in the sclerotic temporal bone by spiral high-resolution computed tomography” at XVIII IFOS World Congress (June 25–30, 2006, Rome, Italy).     

正常人面神经管垂直部与外耳道解剖位置关系的影像与临床研究

目的 观察、测量面神经管垂直部毗邻解剖关系及乳突的形态学指标,分析面神经管垂直部和外耳道后壁、外耳门后缘位置变化的相关性,探讨乳突气化程度与面神经管垂直部之间的关系及临床意义。 方法 1. 评价CT影像测量相关结构的正确性,采用64层螺旋CT对4具干颅标本进行扫描,在横断位测量面神经管垂直部至外耳道后壁、外耳门后缘的距离,在矢状平面上测量乳突的前后径（外耳道下壁最低点至乳突后缘的水平距离）和高度（外耳道下壁至乳突尖的垂直距离）;按影像层面锯开标本,对上述距离行实体测量。影像测量均值与实体测量均值的差异行显著性检验。2. 在体研究：随机入选无耳部疾患的118人（236侧）,其中男性55例（110侧）,女性63例（126侧）,行颌面部CT扫描。如上选择层面,并测量面神经管垂直部至外耳道后壁、外耳门后缘及乳突前后径和高度的距离,以乳突前后径与高度乘积的1/2定义为乳突面积,以乳突面积的大小来定义乳突气化程度,同时将乳突面积分别与面神经管垂直部至外耳道后壁、外耳门后缘距离分别进行相关和回归分析。 结果 1. 标本部分：各项指标的影像测量值与实体测量值差异无统计学意义（P>0.05）。2. 在体研究：各项指标测量结果侧别差异无统计学意义（P>0.05）,性别差异有统计学意义（P<0.05）。乳突面积与面神经管垂直部至外耳道后壁距离之间呈负相关性,且相关性有统计学意义;乳突面积与面神经管垂直部至外耳门后缘有相关性,但相关性无统计学意义。 结论 乳突发育气化好,面神经垂直部位置偏前。 CT检查可以明确面神经管垂直部与外耳道后壁的关系,有助于耳外科手术术式的选择以及对术中重要结构损伤的控制。     

面听神经血管压迫综合征患者小脑下前动脉血管袢与患者典型面听神经症状的MRI研究

目的 探讨小脑下前动脉前(AICA)血管袢的位置对面听神经血管压迫综合征患者典型面、听神经症状的影响。方法 回顾性研究。纳入兰州大学第二医院核磁共振科311例患者(622侧耳)内耳MR可变翻转角三维快速自旋回波(3D-SPACE)序列影像资料,其中男113例、女198例,年龄22~77(48±10.8)岁。统计AICA血管袢发生率及其Chavda分型占比。311例中,单侧面肌痉挛患者107例,比较其患侧(107侧)与健侧(107侧)AICA血管袢发生率、Chavda分型占比,以及AICA走行全程与神经有无接触。自血管袢阳性患者中选择90例(148侧)为血管袢组,比较不同Chavda分型AICA血管袢患者临床表现的差异;将ChavdaⅡ型及Ⅲ型的63侧耳纳入内耳道内血管袢组,将内耳道中的神经分布分为4个象限,观察AICA血管袢与面、听神经接触的位置象限不同的患者间典型面、听神经症状的差异。结果 本组311例622侧患者AICA血管袢的发生率为65.43%(407/622),其中双侧AICA血管袢形成144例、单侧119例,ChavdaⅠ型170侧(41.77%)、Ⅱ型189侧(46.44%)、Ⅲ型48侧(11.79%)。107例单侧面肌痉挛患者健侧AICA血管袢发生率为71.96%(77/107)、患侧70.09%(75/107),两侧比较差异无统计学意义(P＞0.05);健侧和患侧神经血管接触率分别为57.9%(62/107)、43.9%(47/107),差异有统计学意义(χ²=4.207, P＜0.05)。血管袢组90例(148侧)中,不同Chavda分型患者面肌痉挛、听力下降、耳鸣症状的发生率比较,差异均无统计学意义(P值均＞0.05);内耳道内血管袢组共63侧,内耳道内AICA血管袢所处象限不同患者的典型面、听神经症状比较,差异均无统计学意义(P值均＞0.05)。结论 内耳MR 3D-T₂-SPACE成像可清晰显示AICA血管袢及其与内耳道的位置关系,血管袢深度、位置对面听神经压迫综合征典型面、听神经症状无明显影响。     

The Effect of sex steroid hormones on substrate oxidation during prolonged submaximal exercise in women

In animals, female sex steroid hormones (SS, estrogens-progesterone) influence the energy substrate that is metabolized. Human research on this issue is controversial. This study examined whether changes in circulating SS hormone levels affected the carbohydrate-lipid metabolism during submaximal prolonged (60 min) exercise. Young, physically active females were studied. Four were classified as anovulatory-oligomenorrheic and four were classified as ovulatory-eumenorrheic. Subject responses were pooled to form one group (n = 8) and then their responses under low (L) and high (H) pharmaceutically manipulated SS hormone conditions were examined. During exercise, the mean oxygen consumption levels were 1.70 +/- 0.10/ x min(-1) for L-SS and 1.75 +/- 0.11/ x min(-1) for H-SS (p = 0.07), respectively. The respiratory exchange ratio (RER) responses were significantly different during exercise between the conditions: 0.93 +/- 0.04 for L-SS and 0.90 +/- 0.04 for H-SS (p < 0.05), respectively. RER responses were utilized to calculate substrate oxidation. Significantly less carbohydrate oxidation was found in the H-SS condition as compared to the L-SS condition (p < 0.05). Lipid oxidation was also significantly different, but for this measure, the levels of oxidation were greater in the H-SS than in the L-SS condition (p < 0.05). Finally, total energy expenditure for the 60 min of exercise was not significantly different between the hormonal conditions. Results suggest that sex steroid hormones have an impact upon substrate oxidation in women during exercise. Specifically, high circulating concentrations of the SS hormones result in an enhanced reliance upon the oxidation of lipid as an energy substrate and consequently induce a reduction in carbohydrate oxidation. The mechanism inducing this "metabolism shift" appears due to sex steroid hormones directly and indirectly increasing lipid mobilization and lipolysis.     

Specific IgG antibody subclasses to Angiostrongylus cantonensis in patients with angiostrongyliasis

Total IgG, IgG1, IgG2, IgG3, IgG4, IgA and IgM specific antibodies against Angiostrongylus cantonensis somatic antigen were determined by enzyme-linked immunosorbent assay (ELISA) in sera from proven human angiostrongyliasis (PA) cases, clinically suspected angiostrongyliasis cases with eosinophilic meningitis (EM) and healthy control (HC). The specific IgA antibody in each of the patient groups was significantly higher than those of the HC group (p < 0.05). The mean ELISA value of the specific IgM in the PA group was not significantly different from that of the HC group (p > 0.05). However, the mean specific IgM ELISA value in the EM group was significantly higher than that of the HC group (p < 0.05). The levels of the specific IgG and IgG subclasses in both patient groups were significantly higher than in the healthy control (HC) group (p < 0.001). Major differences were evident in the distribution of the IgG subclass antibodies between the patient groups. The IgG1 antibody demonstrated the highest sensitivity and specificity while the IgM and IgA responses were generally poor in both patient groups. The levels of the specific IgG antibody subclasses possibly explain immune responses to the parasite.     

The relationship between presbycusis and mastoid pneumatization

Presbycusis is defined as the natural hearing loss accompanying aging, caused by degenerative changes in the inner ear. The etiology of presbycusis is uncertain. However, it would appear that a complex genetic cause is most likely. The determinants of mastoid size continue to be controversial. One of the pneumatization theories is the hereditary theory. In this study, the possible relationship between presbycusis and the extent of mastoid pneumatization was investigated. This study was carried out on 21 patients with presbycusis and 21 normal subjects of similar ages. The pneumatized volume was measured by computerized tomography. The temporal bone was scanned at 2 mm thickness intervals. Exposure (kV 130, mA105). The scan plane was parallel to the orbitomeatal line and the CT images covered the entire mastoid region. The average mastoid pneumatization in presbycusis group was 6.08 +/- 2.52 cm(3) in the right ear and 6.19 +/- 2.93 cm(3) in the left ear. However, in the control group it was 4.69 +/- 3.17 cm(3) in the right ear (p=0.12) and 5.10 +/- 3.49 cm(3) in the left ear (p=0.28). No significant difference was found between the presbycusis patients and normal subjects in terms of the volume of mastoid pneumatization.     

自体肋软骨支架复合乳突区皮肤扩张再造耳郭46例

背景：耳郭支架再造可供选择的材料较多,总体分为人工合成材料及自体组织两种,但各有利弊。 目的：回顾性分析自体肋软骨支架并乳突区皮肤扩张耳郭重建后的临床效果及并发症发生情况。 方法：选择淮安市第一人民医院烧伤整形科进行人工耳郭再造的患者46例,入院后行乳突区皮肤扩张,采用自体肋软骨支架耳郭再造,乳突区皮瓣转移覆盖的方法进行耳郭再造,观察再造效果及再造后并发症发生情况。 结果与结论：46例患者均获得满意耳郭再造效果,耳郭形态逼真,耳颅角清晰。患者治疗后3个月,再造侧耳颅角、耳郭长度及耳郭高度同健侧比较,差异无显著性意义(P > 0.05)。患者治疗后3个月及1年再造耳耳颅角、耳郭长度及耳郭高度比较差异无显著性意义(P> 0.05)。提示乳突区皮肤扩张肋软骨支架耳郭再造安全性高,能够取得较好的再造效果。     

Körner’s septum (petrosquamosal lamina) and chronic ear disease

To assess the clinical significance of Körners septum (KS) or petrosquamosal (PS) lamina in different chronic ear pathologies, a surgical and anatomic study was carried out, in which the significance of KS was assessed in various otologic diseases. Of 639 patients who underwent ear surgery between 1998 and 2001, 426 were included in the study. The diagnoses were chronic otitis media without cholesteatoma (COM), tympanosclerosis (TS), adhesive otitis media (AOM) and cholesteatoma (COL) in 160, 100, 70 and 96 patients respectively. The operative records of the patients were reviewed for the presence of KS. There was antral blockage by KS in all patients who also had Cog (the middle portion of the PS lamina). KS was mostly seen in cases of TS. The prevalence of KS was not significantly different when the result of the COM group was compared with that of the COL and AOM groups ( p >0.05). The prevalence of KS was significantly higher in patients with TS than in those with COM. Both antral and epitympanic blockages were more prevalent in cases of TS than in those of COM (² =3.9, p =0.04 and ² =6.6, p =0.01 respectively). There is a significant association between the presence of KS and TS. Based on this finding, it is recommended that a mastoidectomy be performed in cases of severe tympanosclerosis in order to remove KS. How the removal of this anatomic impact will affect the natural course of the disease is still a question that needs further investigation.Part of this study was presented at the International Symposium on Morphological Sciences on September11–15, 2002, in Romania     

Effect of anterior tympanomeatal angle blunting on the middle ear transfer function using a finite element ear model

The anterior tympanomeatal angle (ATA) blunting is clinically defined as a certain degree of the ATA obliteration due to excessive fibrous tissue formation, which is a relatively common complication of external auditory canal (EAC) related operations. The aim of this study was to examine the effect of ATA blunting on the middle ear transfer function using a finite element (FE) model. Results showed that the displacements at the tympanic membrane (TM), at the manubrium and at the stapes footplate, and also the ratio of stapes footplate velocity to the sound pressure in the EAC were decreased to various degrees from ATA blunting of Grades 1–4. This was more significant with TM thickening at the frequencies below 3.2 kHz, particularly in Grades 3 and 4 when analyzing the anterior region of the TM. The phase differences of TM and stapes footplate increased with the ATA blunting from Grades 1 to 4 in relation to normal ATA. It is noteworthy that the vibration mode of the malleus does not show obvious change, compared to the displacement reduction at the TM with ATA blunting Grades 1–4. These results suggest that FE analysis of ATA blunting effect appears to be effective.     

Neuroendocrine adenoma of the middle ear with extension into the external auditory canal

We report a case of middle ear adenoma (neuroendocrine adenoma of the middle ear) protruding into the external ear canal. The patient was a 65-year-old man with hearing alterations and a headache in whom an otoscopy disclosed a sessile, pea-sized, brown-reddish, focally bleeding mass located in the posterior-superior aspect of the right external auditory canal. Histopathologically, there was a neoplasm composed of closely packed, sometimes back-to-back glandular structures formed by small uniform cuboidal or cylindrical cells. Small solid islands were also present. Following the histopathologic examination, a high resolution computed tomography was performed showing an extensive osteolytic defect mostly involving the mastoid air cells of the mastoid process with a partial destruction of the middle ear cavity. This defect was filled with a mass-like lesion with the density of soft tissue which bulged to the external auditory canal. Histopathologic examination of the mass in the middle ear cavity revealed findings identical to those seen in the original biopsy, confirming diagnosis of middle ear adenoma extending into the external ear canal. Keywords: skin - external auditory canal - neuroendocrine adenoma of the middle ear - carcinoid tumor.     

耳内镜下新西兰兔中耳的解剖研究

目的　耳内镜下观察兔中耳解剖结构,探讨兔作为耳内镜解剖训练模型的可行性,为兔中耳相关的其他实验研究提供解剖学依据。 方法　5只（10耳）新西兰兔麻醉处死后,耳内镜下经外耳道入路观察兔鼓膜、中耳鼓室结构,辨别听小骨、上中下鼓室、面神经等。 结果　与人对比,新西兰兔听小骨由锤砧联合体和镫骨组成;上鼓室外侧壁部分骨质缺如,由鼓膜向上延续并覆盖;听泡类似于人的中、下鼓室,包含咽鼓管、面神经、鼓岬、前庭窗、蜗窗以及鼓室神经等结构,乳突为听泡尾侧的板障型骨管;面神经鼓室段水平走行于上鼓室下方骨壁内,后经锥隆起垂直走行于听泡后壁,经茎乳孔出听泡。 结论　新西兰兔中耳结构与人相似,既可作为耳科医生练习耳内镜操作的解剖模型,也可作为耳部三维解剖结构的教学标本。     

面神经鼓乳段在斜矢状断面与HRCT上的定位及临床意义

目的　探讨面神经鼓乳段在斜矢状位最佳显示的扫描基线,为面神经鼓乳段疾病的影像诊断和耳显微外科手术治疗提供解剖学依据。 方法　利用HRCT对16例(32耳) 外观无异常的成人颅骨标本行斜矢状位扫描获得层厚为0.625 mm的HRCT图像后,再用火棉胶包埋技术将颞骨标本切制层厚为1mm的连续斜矢状断面标本,选取面神经鼓乳段显示良好的CT图片与对应的切片标本对照观测。 结果　16例（32耳）在斜矢状位均可完整显示面神经鼓乳段全程,面神经鼓乳段全长为（23.58±1.44）mm,鼓室段到外半规管的距离为（0.75±0.12）mm,面神经鼓室段到鼓室的距离为（0.34±0.08）mm,鼓室段和乳突段的夹角为（108.88±2.49）度。 结论　颞骨斜矢状位HRCT图像结合对应切片标本能良好显示面神经鼓乳段及其周围结构的解剖位置和毗邻关系,以与正中矢状面成（21.40±4.35）度为扫描基线作斜矢状位扫描显示面神经鼓乳段最佳,对颞骨的影像诊断和耳显微外科手术治疗具有重要意义。     

耳内镜下新西兰兔中耳的解剖研究

目的　耳内镜下观察兔中耳解剖结构,探讨兔作为耳内镜解剖训练模型的可行性,为兔中耳相关的其他实验研究提供解剖学依据。 方法　5只（10耳）新西兰兔麻醉处死后,耳内镜下经外耳道入路观察兔鼓膜、中耳鼓室结构,辨别听小骨、上中下鼓室、面神经等。 结果　与人对比,新西兰兔听小骨由锤砧联合体和镫骨组成;上鼓室外侧壁部分骨质缺如,由鼓膜向上延续并覆盖;听泡类似于人的中、下鼓室,包含咽鼓管、面神经、鼓岬、前庭窗、蜗窗以及鼓室神经等结构,乳突为听泡尾侧的板障型骨管;面神经鼓室段水平走行于上鼓室下方骨壁内,后经锥隆起垂直走行于听泡后壁,经茎乳孔出听泡。 结论　新西兰兔中耳结构与人相似,既可作为耳科医生练习耳内镜操作的解剖模型,也可作为耳部三维解剖结构的教学标本。     

Lsr2 peptides of Mycobacterium leprae show hierarchical responses in lymphoproliferative assays, with selective recognition by patients with anergic lepromatous leprosy

Lsr2 protein of Mycobacterium leprae was shown earlier to elicit B and T cell responses in leprosy patients (20, 28). Lymphoproliferation to M. leprae and Lsr2 antigens was observed in >70% of tuberculoid (T) patients and in 16 and 34% of lepromatous (L) patients, respectively. We focused on the M. leprae nonresponders in the lepromatous group using 22 synthetic Lsr2 peptides (end-to-end peptides A to F and overlapping peptides p1 to p16) in in vitro T cell responses. A total of 125 leprosy and 13 tuberculosis patients and 19 healthy controls from the area of endemicity (here, healthy controls, or HC) were investigated. The highest responses were observed (67 to 100%) in HC for all peptides except p1 to p3, and the lowest was observed in tuberculosis patients. Significant differences in lymphoproliferation were observed in T, L, and HC groups (analysis of variance [ANOVA], P = 0.000 to 0.015) for all end-to-end peptides except B and for p5 and p7 to p10. Hierarchical recognition between lepromatous and tuberculoid leprosy was noted for p8 (P < 0.05) and between the HC and L groups for p7 to p10, p15, and p16 (P < 0.005 to P < 0.02). Significant lymphoproliferation was observed to peptides A to F and p1 to p9, p11, p12, p15, p16 (P = 0.000 to 0.001) with 40% responding to peptides C and p16 in L patients. Lepromatous patients also showed significantly higher levels of a gamma interferon (IFN-γ) response to peptide C than to other peptides (P < 0.05). Major histocompatibility complex (MHC) class II bias for peptide recognition was not observed. These studies indicate that Lsr2 has multiple T cell epitopes that induce in vitro T cell responses in the highly infective lepromatous leprosy patients.     

Changes in external ear position modify the spatial tuning of auditory units in the cat's superior colliculus

This study examines the influence of external ear position on the auditory spatial tuning of single units in the superior colliculus of the anesthetized cat. Unit responses to broad-band stimuli presented in a free sound field were measured with the external ears in a forward symmetrical position or with one or the other ear turned 40 degrees to the side; the ears are referred to as contra- or ipsilateral with respect to the side of the recording site. Changes in the position of either ear modified the spatial tuning of units. The region of space from which a stimulus was most effective in activating a unit is referred to as the unit's "best area". Whenever the contralateral ear was turned to the side, best areas shifted peripherally and somewhat upward, roughly in proportion to the magnitude of the change in ear position. A turn of the ipsilateral ear to the side had more variable effects, but best areas generally shifted frontally. Best areas located between approximately 10 and 40 degrees contralateral when the ears were forward were least affected by changes in ipsilateral ear position. Changes in ear position also modified the maximum response rates of many units. Units with best areas located within approximately 20 degrees of the frontal midline when the ears were forward exhibited a pronounced decrease in responsiveness when either ear was turned. Units with more peripheral best areas tended to show no change or a slight increase in responsiveness. The influence of ear position on the directionality of the external ears was determined by mapping the cochlear microphonic response to tones or one-third-octave bands of noise before and after turning the ear. When the ears were forward, maximum interaural intensity differences (IIDs) were produced by high-frequency sound sources (greater than or equal to 20 kHz) located 20-40 degrees from the frontal midline and by lower frequency sources located further peripherally. The influence of ear position on the locations from which maximum IIDs were produced was similar to the influence of ear position on unit best areas. Changes in ipsilateral ear position had different effects on high- and low-frequency IIDs that were comparable with the effects of changes in ear position on frontally and peripherally located best areas, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)     

Modification of neuromagnetic responses of the human auditory cortex by masking sounds

Summary We have studied the effects of masking sounds on auditory evoked magnetic fields (AEFs) of healthy humans. The AEFs were elicited by 25-ms tones presented randomly to the left or to the right ear, and the responses were recorded over the right auditory cortex. Without masking, the 100-ms deflection (N100m) was of somewhat higher amplitude and of shorter latency for contrathan ipsilateral stimuli. Continuous speech, music, or intermittent noise, delivered to the left ear, dampened N100m to stimulation of both ears without correlated changes in sensation. Intermittent noise had a weaker effect on N100m than speech or music. Continuous noise fed to the left ear dampened both the sensation of and the responses to the left-ear stimuli, with no significant effect on the responses to the right-ear stimuli. The results suggest that the masking effects of continuous noise, seen at the auditory cortex, derive mainly from the periphery whereas the effects of sounds with intensity and frequency modulations take place at more central auditory pathways.