Concurrent Development of the Head and Pinnae and the Acoustical Cues to Sound Location in a Precocious Species,the Chinchilla (<Emphasis Type="Italic">Chinchilla lanigera)</Emphasis>

Sounds are filtered in a spatial- and frequency-dependent manner by the head and pinna giving rise to the acoustical cues to sound source location. These spectral and temporal transformations are dependent on the physical dimensions of the head and pinna. Therefore, the magnitudes of binaural sound location cues—the interaural time (ITD) and level (ILD) differences—are hypothesized to systematically increase while the lower frequency limit of substantial ILD production is expected to decrease due to the increase in head and pinna size during development. The frequency ranges of the monaural spectral notch cues to source elevation are also expected to decrease. This hypothesis was tested here by measuring directional transfer functions (DTFs), the directional components of head-related transfer functions, and the linear dimensions of the head and pinnae for chinchillas from birth through adulthood. Dimensions of the head and pinna increased by factors of 1.8 and 2.42, respectively, reaching adult values by ~6 weeks. From the DTFs, the ITDs, ILDs, and spectral shape cues were computed. Maximum ITDs increased by a factor of 1.75, from ~160 μs at birth (P0-1, first postnatal day) to 280 μs in adults. ILDs depended on source location and frequency exhibiting a shift in the frequency range of substantial ILD (>10 dB) from higher to lower frequencies with increasing head and pinnae size. Similar trends were observed for the spectral notch frequencies which ranged from 14.7–33.4 kHz at P0-1 to 5.3–19.1 kHz in adults. The development of the spectral notch cues, the spatial- and frequency-dependent distributions of DTF amplitude gain, acoustic directionality, maximum gain, and the acoustic axis were systematically related to the dimensions of the head and pinnae. The dimension of the head and pinnae in the chinchilla as well as the acoustical properties associated with them are mature by ~6 weeks.     

Geometry of the semicircular canals of the chinchilla (Chinchilla laniger)

The orientations of the semicircular canals determines the response of the canals to head rotations and, in turn, the brain's ability to interpret those motions. The geometry of chinchillas' semicircular canals has never been reported. Volumetric representations of three chinchilla skulls were generated using a microCT scanner. The centroids of each semicircular canal lumen were identified as they passed through the image slices and were regressed to a plane. Unit vectors normal to the plane representing canal orientations were used to calculate angles between canal pairs. Pitch and roll maneuvers required to bring any canal into the horizontal plane for physiologic investigation were calculated. The semicircular canals of the chinchilla were found to be relatively planar. The horizontal canal was found to be oriented 55.0 degrees anteriorly upward. Pairs of ipsilateral chinchilla canals were not orthogonal and contralateral synergistic pairs were not parallel. Despite this arrangement, the canal plane unit normal vectors were organized to respond with approximately equal overall sensitivity to rotations in any direction. The non-orthogonal chinchilla labyrinth may provide an opportunity to determine whether the frame of reference used by the central vestibular and oculomotor system is based on directions of afferent maximum sensitivity or prime directions.     

Temporal and spatial coding of periodicity information in the inferior colliculus of awake chinchilla (Chinchilla laniger)

Amplitude modulation responses and onset latencies of multi-unit recordings and evoked potentials were investigated in the central nucleus of inferior colliculus (ICC) in the awake chinchilla. Nine hundred and one recording sites with best frequencies between 60 and 30 kHz showed either phasic (18%), tonic (25%), or phasic-tonic (57%) responses. Of 554 sites tested for responses to modulation frequencies 73% were responsive and 57% showed clear preference for a narrow range of modulation frequencies. Well defined bandpass characteristics were found for 32% of rate modulation transfer functions (rate-MTFs) and 36% of synchronization MTFs (sync-MTFs). The highest best modulation frequency (BMF) of a bandpass rate-MTF was 600 Hz. Neurons with phasic responses to best-frequency tones showed strong phase coupling to modulation frequencies and were dominated by bandpass rate-MTFs and sync-MTFs. Most neurons with tonic responses showed bandpass tuning only for sync-MTFs. Both BMFs and onset latencies changed systematically across frequency-band laminae of the ICC. Low BMFs and long latencies were located medially and high BMFs and short latencies laterally. Latency distributions obtained with evoked potentials to clicks showed a similar gradient to the multi-unit data. These findings are in line with previous findings in different animals including humans and support the hypothesis that temporal processing results in a topographic arrangement orthogonal to the spectral processing axis, thus forming a second neural axis of the auditory system.     

外耳道对鼓膜外表面的增压作用——成人有限元模型研究

目的　研究外耳道对鼓膜外表面的增压作用。方法　依据1例成年男性颞骨标本的Micro-CT扫描数据,利用Mimics软件、ANSYS软件建立正常成人中耳有限元模型后,计算一定声压刺激及外耳道条件下鼓膜表面的声压分布情况。结果　当90 dB SPL（0.632 Pa）均匀声压加载于所建模型外耳道口进行0.2～8 kHz范围内的谐响应分析时, 声压在鼓膜外表面得到增强,且具有频率特异性。于声压直接加载与鼓膜外表面向比,外耳道于0.5、1.0、2.0、3.2、4.0 kHz使得鼓膜表面声压增加分别为0.038、0.118、0.318、1.478、1.088 Pa,换算为分贝,则鼓膜外表面声压分别增加0.5、1.5、3.5、10.5、8.7 dB。结论　有限元模型研究显示外耳道对鼓膜外表面有明显频率特异性的增压作用,于共振频率处最强。进一步颞骨实验研究将加深该领域认知。     

Embryonal rhabdomyosarcoma of the head and neck in an adult

Objective

This report describes an exceedingly rare case of adult embryonal rhabdomyosarcoma arising in the head and neck, which was initially diagnosed as a primary unknown cancer.

Method

The patient underwent a radical neck dissection with the total excision of the tumor, which was diagnosed as embryonal rhabdomyosarcoma.

Result

The patient received intensive adjuvant chemotherapy, and is still alive with no signs of recurrence or metastasis.

Conclusion

This case report demonstrates not only the rarity of this neoplasm but the importance of the differential diagnosis for planning the therapeutic strategy.     

Squamous carcinoma of the head and neck in the young adult

We present a series of 2305 previously untreated histologically proven squamous carcinomas of the mucosal surfaces of the upper aerodigestive tract managed by one of us in a 27-year period. 62 (2.7%) of the patients were aged 40 years or younger. The sex ratio between young and old patients was similar but, as expected, the younger patients were in better physical condition. Furthermore, 90% of young patients were treated, compared with only 78% of the older patients. Younger patients had a higher incidence of oropharyngeal tumours and lymph node metastases, but the proportion of poorly differentiated tumours, and stage T₃-T₄ tumours, was similar, as was the metastatic rate. The crude survival of the younger patients was 10% better than that of the older group, and adjusted (life-table) survival was 9% better, and this better survival in younger patients was significant when differing site incidence and N-stage were allowed for by multivariate analysis. The recurrence rate at the primary site was 19% in the younger patients and 15% in older patients, but this difference was not significant. The recurrence rate in cervical lymph nodes was similar in both age groups: 37% at 2 years in young patients and 38% in older patients.     

Simultaneous (non-epidermoid) neoplasms involving the head and neck

The phenomenon of multiple primary malignant neoplasms involving the head and neck is well documented. Epidermoid carcinomas constitute the majority of these neoplasms. Case reports are made of two patients with simultaneously occurring chronic reticuloendothelial malignancies and non-epidermoid tumors involving the head and neck. The first case is one of chronic lymphocytic leukemia (CLL) and metastatic primary retro-peritoneal extragonadal seminoma, while the second is one of lymphocytic lymphoma (LL) and a carotid body tumor (CBT). The head and neck manifestations of metastatic seminoma, CBT, and CLL and LL are discussed. A review of the literature of the association of each of these entities to other tumors is presented. Also presented is the evidence for an increased incidence of malignancies associated with CLL and LL and the complicating factors introduced when reticuloendothelial malignancies occur simultaneously with head and neck neoplasms.     

Squamous carcinoma of the head and neck in the young adult.

We present a series of 2305 previously untreated histologically proven squamous carcinomas of the mucosal surfaces of the upper aerodigestive tract managed by one of us in a 27-year period. 62 (2.7%) of the patients were aged 40 years or younger. The sex ratio between young and old patients was similar but, as expected, the younger patients were in better physical condition. Furthermore, 90% of young patients were treated, compared with only 78% of the older patients. Younger patients had a higher incidence of oropharyngeal tumours and lymph node metastases, but the proportion of poorly differentiated tumours, and stage T3-T4 tumours, was similar, as was the metastatic rate. The crude survival of the younger patients was 10% better than that of the older group, and adjusted (life-table) survival was 9% better, and this better survival in younger patients was significant when differing site incidence and N-stage were allowed for by multivariate analysis. The recurrence rate at the primary site was 19% in the younger patients and 15% in older patients, but this difference was not significant. The recurrence rate in cervical lymph nodes was similar in both age groups: 37% at 2 years in young patients and 38% in older patients.     

Malherbe's calcifying epithelioma (pilomatrixoma) of the head and neck

Calcifying Epitheliomas of Malherbe (Pilomatrixomas) are benign tumors that have their origin in the hair matrix and clinically resemble a hard subcutaneous swelling. Most of these tumors are placed in the head and neck region, in our sample the Pilomatrixomas of this location were 49.6% of the total. The middle age of presentation of this tumor were 32.2 years, with two main peaks of incidence below 20 years and under 50. The most frequent locations were the auricular, cervical, ciliar, frontal, and temporal regions, with one case of multiple location. The middle size of the tumor in our sample was 1.2 cm. In this paper we review the main pathologic, clinic and therapeutic features of this lesion in the head and neck region.     

Aggressive fibromatosis of the head and neck (desmoid tumours)

Desmoid tumours are histologically benign fibrous neoplasms arising from the musculoaponeurotic structures throughout the body. They are characterized as infiltrative, usually well-differentiated firm overgrowth of fibrous tissue and are locally aggressive. An aggressive clinical behaviour with tendency for recurrence makes the treatment of these relatively rare fibrous tumours difficult. Local recurrence rates are reported as high as 70 per cent of cases, the recurrence of desmoid fibromatosis in the head and neck is difficult to ascertain because of the different classification schemes used by different authors. A review of cases of desmoid tumours of the head and neck presented in the last 10 years is reported in this paper. Complete surgical excision of desmoid tumours is considered to be the only effective method of cure by most authorities.     

Adenoid cystic carcinomas of the head and neck (cylindromas)

In the years 1958-1997 111 patients with adenoid cystic carcinoma in the head and neck of different localization were treated at the Department of Otolaryngology--Head and Neck Surgery. Majority of the tumors originated of the major salivary glands, mainly in the parotid gland (47 cases). The most common location among the tumor of the minor salivary glands was the palate (14 persons). The tumors arising from other mucous glands, most frequently has located in the maxillo-ethmoideal complex (20 cases). The authors stress diagnostic difficulties, the necessity of a proper selection of the surgical method and postoperative radiotherapy, describing the treatment results in the patients. Radial surgical procedure of the adenoid cyctic carcinoma yelds optimal local control and survival rates.     

Human papilloma virus (HPV) and carcinomas of the head and neck

Increasing evidence for a causal link between human papilloma virus and carcinomas of the cervix has emerged in recent research. This group of species-specific, epitheliotropic viruses has also been associated with tumours of the head and neck, but the individual reports deal only with relatively small sample numbers. In the present review these reports are considered in relation to the methods employed, and it is concluded that HPV is associated with more than 50% of oral and nasal carcinomas, as well as with carcinomas of the larynx and oesophagus. The clinical relevance and strategies for future work are outlined.     

头颈部异位脑膜瘤(附10例报告)

目的：提高临床对头颈部异位脑膜瘤的诊治水平。方法：回顾性分析了１０例头颈异位脑膜瘤的资料其中内皮型脑膜瘤２例,砂粒体型脑膜瘤２例,过渡型脑膜瘤２例,过渡型脑膜瘤１例,恶性脑膜瘤１例,余者为分型。所有病例均行手术治疗。结果：４例复发后再次手术后随访多年未再复发。结论：头颈部异位脑膜瘤的治疗应以手术为主。     

Treatment of lymphangiomas of the head and neck in children by intralesional injection of OK-432 (Picibanil)

The treatments previously used for lymphangiomas of the head and neck in children-surgery and intralesional injection of sclerosants-are associated with significant morbidity. A new treatment-intralesional injection of OK-432-was used for lymphangiomas of the head and neck in 11 children. The results were total shrinkage in two, marked shrinkage in two, slight shrinkage in five and no response in two. The results were not affected by previous surgery nor by whether aspiration prior to injection was possible. There were no recurrences in those children in whom shrinkage occurred and no child had subsequent surgery following injection. The results of this series support those of previous series showing that OK-432 injection is an effective and safe treatment for lymphangiomas of the head and neck in children.     

Modulation of vestibulo-ocular reflex (VOR) by active stabilization of head to trunk

Horizontal vestibulo-ocular reflex (VOR) with covered eyes was tested in 15 healthy subjects sitting on a rotation chair (40 degrees, 0.05, 0.1, 0.2, 0.33 Hz) under two conditions: (a) head fixed to chair by a neck support; (b) with instruction to turn the head together with the passively moved trunk. In situation (b), saccadic amplitudes/sec, nystagmus frequency, gain of nystagmus slow phase velocity and amplitudes of maximum eye shift were enhanced significantly. The phase of maximum eye shift changed from 180 degrees up to 270 degrees with respect to stimulus position. The distribution of nystagmus saccades over the stimulus period showed enhanced peak values and a slight phase shift.