Suppressing artifacts in the total focusing method using the directivity of laser ultrasound.

Based on a synthesized laser ultrasonic array, full matrix capture can be used to acquire data, which can then be post-processed using the total focusing method. However, this noncontact ultrasonic imaging technique has not been widely used because of the numerous artifacts in ultrasonic images and time-consuming data acquisition. To address these issues, this study proposes a post-processing algorithm, which uses the laser ultrasound directivity information to suppress the artifacts in the total focusing method's images. In particular, a weight factor is defined using the directivity information. By multiplying the image intensity of the total focusing method with this factor, the algorithm uses not only the amplitude and phase information of laser ultrasound but also its directivity information. The experimental results indicate that four types of artifacts are suppressed. Because the grating lobe artifacts can be suppressed, a larger element spacing can be used to reduce the data acquisition time.

Nondestructive evaluation of demineralized enamel in a human incisor and molar using laser ultrasonics.

This study aims to evaluate early caries in human teeth with different geometry structures by using the dispersion curves of a surface acoustic wave (SAW) generated by a pulsed laser. Through the finite element method, SAWs propagating on teeth models with different enamel thickness and curvature radius were simulated, and the influence of the geometry difference on the dispersion curves of SAWs was discussed. Laser ultrasonic experiments were performed on an extracted human incisor and molar with different demineralization conditions. The received dispersive surface wave signals were processed via the spectral analysis method to obtain the dispersion curves, and the difference of the dispersion spectra between the incisor and the molar was analyzed and discussed. The result demonstrates that the laser generating the SAW has the ability to evaluate the elastic properties of early caries with different geometry nondestructively.

A survey on hearing acuity of centenarians in Hainan Province.

OBJECTIVE: This study aimed to investigate hearing acuity of centenarians in Hainan Province and provide basis for interventional considerations. METHOD: Door-to-door follow-up was conducted to investigate hearing acuity of centenarians (aged 100 years or above) in Hainan Province. Physical examination, pure tone audiometry and acoustic impedance test were performed, and the results were analyzed. RESULT: A total of 460 centenarians (920 ears) were tested by pure tone audiometry. The rate of normal hearing was 0.2%, the rate of mild hearing loss was 1.5%, 12% for moderate hearing loss, 33.9% for moderate to severe hearing loss, 37.4% for severe hearing loss is and 15% for profound hearing loss. Acoustic impedance test was performed in 340 centenarians (668 ears). Tympanogram was type A in 41.2% of the ears, type As in 34.1% ears, type Ad in 6.4%, type B in 11.8%, and type C in 4.9% of the ears, while no response was elicited in 1.5% of the ears. CONCLUSION: Age related sensorineural hearing loss is prevalent among centenarians in Hainan Province. A probably beneficial intervention may be the use of hearing aids for effective communication.

Study of the impact of truncations on wedge waves by using the laser ultrasound technique.

This research focuses on measuring the impact of truncations on the dispersion characteristics of wedge waves propagating along the wedge tip by using the laser-generated ultrasound. First, the finite element method was used to simulate laser-induced wedge waves and the dispersion curves were obtained by using the 2D Fourier transformation method. Pulsed laser excitation and laser-based wedge wave detection were also utilized to investigate these characteristics experimentally. For the 20° and 60° line wedges, both experimental and numerical results indicated that a nonideal wedge tip had great impact on the wedge waves. The modes of the 20° line wedge with truncations presented anomalous dispersion, low mode closed to high mode in high frequency, and the characteristics of antisymmetric Lamb waves as truncation increased. Meanwhile, the modes of the 60° line wedge with truncations showed the characteristics of antisymmetric Lamb waves, and the A1 mode was also observed clearly. The findings of this study can be used to evaluate and detect wedge structure.

Scanning laser-line source technique for nondestructive evaluation of cracks in human teeth.

This paper describes the first application of a remote nondestructive laser ultrasonic (LU) system for clinical diagnosis of cracks in human teeth, to our knowledge. It performs non-contact cracks detection on small-dimension teeth samples. Two extracted teeth with different types of cracks (cracked tooth and craze lines), which have different crack depths, are used as experimental samples. A series of ultrasonic waves were generated by a scanning laser-line source technique and detected with a laser-Doppler vibrometer on the two samples. The B-scan images and peak-to-peak amplitude variation curves of surface acoustic waves were obtained for evaluating the cracks' position and depth. The simulation results calculated by finite element method were combined with the experimental results for accurately measuring the depth of crack. The results demonstrate that this LU system has been successfully applied on crack evaluation of human teeth. And as a remote, nondestructive technique, it has great potential for early in vivo diagnosis of cracked tooth and even the future clinical dental tests.

Experimental and numerical studies for nondestructive evaluation of human enamel using laser ultrasonic technique.

In this paper, a nondestructive laser ultrasonic technique is used to generate and detect broadband surface acoustic waves (SAWs) on human teeth with different demineralization treatment. A scanning laser line-source technique is used to generate a series of SAW signals for obtaining the dispersion spectrum through a two-dimensional fast Fourier translation method. The experimental dispersion curves of SAWs are studied for evaluating the elastic properties of the sound tooth and carious tooth. The propagation and dispersion of SAWs in human teeth are also been studied using the finite element method. Results from numerical simulation and experiment are compared and discussed, and the elastic properties of teeth with different conditions are evaluated by combining the simulation and experimental results.

MGRN1-dependent pigment-type switching requires its ubiquitination activity but not its interaction with TSG101 or NEDD4.

Mice lacking the E3 ubiquitin ligase mahogunin ring finger-1 (MGRN1) have a pleiotropic phenotype that includes spongiform neurodegeneration, embryonic patterning defects, and dark fur due to a defect in pigment-type switching. The only MGRN1 ubiquitination target identified to date is tumor susceptibility gene 101 (TSG101), a component of the endosomal trafficking machinery. Here, we show that MGRN1 also interacts with but does not ubiquitinate NEDD4, a HECT-domain ubiquitin ligase involved in endosomal trafficking. Using transgenesis in mice, we demonstrate that pigment-type switching likely requires MGRN1's ubiquitin ligase activity but not its ability to bind TSG101 or NEDD4. This indicates that MGRN1-dependent ubiquitination of an as-yet unidentified target protein is required for agouti-mediated melanocortin signaling.

Abnormal regulation of TSG101 in mice with spongiform neurodegeneration.

Spongiform neurodegeneration is characterized by the appearance of vacuoles throughout the central nervous system. It has many potential causes, but the underlying cellular mechanisms are not well understood. Mice lacking the E3 ubiquitin ligase Mahogunin Ring Finger-1 (MGRN1) develop age-dependent spongiform encephalopathy. We identified an interaction between a "PSAP" motif in MGRN1 and the ubiquitin E2 variant (UEV) domain of TSG101, a component of the endosomal sorting complex required for transport I (ESCRT-I), and demonstrate that MGRN1 multimonoubiquitinates TSG101. We examined the in vivo consequences of loss of MGRN1 on TSG101 expression and function in the mouse brain. The pattern of TSG101 ubiquitination differed in the brains of wild-type mice and Mgrn1 null mutant mice: at 1 month of age, null mutant mice had less ubiquitinated TSG101, while in adults, mutant mice had more ubiquitinated, insoluble TSG101 than wild-type mice. There was an associated increase in epidermal growth factor receptor (EGFR) levels in mutant brains. These results suggest that loss of MGRN1 promotes ubiquitination of TSG101 by other E3s and may prevent its disassociation from endosomal membranes or cause it to form insoluble aggregates. Our data implicate loss of normal TSG101 function in endo-lysosomal trafficking in the pathogenesis of spongiform neurodegeneration in Mgrn1 null mutant mice.

Transgenic analysis of the physiological functions of Mahogunin Ring Finger-1 isoforms.

Mahogunin Ring Finger-1 (Mgrn1) null mutant mice have a pleiotropic phenotype that includes the absence of yellow hair pigment, abnormal head shape, reduced viability, and adult-onset spongiform neurodegeneration. Mgrn1 encodes a highly conserved E3 ubiquitin ligase with four different isoforms which are differentially expressed and predicted to localize to different subcellular compartments. To test whether loss of specific isoforms causes different aspects of the mutant phenotype, we generated transgenes for each isoform and bred them onto the null mutant background. Mice expressing only isoform I or III appeared completely normal. Isoform II rescued or partially rescued the mutant phenotypes, whereas isoform IV had little or no effect. Our data show that different Mgrn1 isoforms are not functionally equivalent in vivo and that the presence of only isoform I or III is sufficient for normal development, pigmentation, and neuronal integrity.

Mitochondrial dysfunction precedes neurodegeneration in mahogunin (Mgrn1) mutant mice.

Oxidative stress, ubiquitination defects and mitochondrial dysfunction are commonly associated with neurodegeneration. Mice lacking mahogunin ring finger-1 (MGRN1) or attractin (ATRN) develop age-dependent spongiform neurodegeneration through an unknown mechanism. It has been suggested that they act in a common pathway. As MGRN1 is an E3 ubiquitin ligase, proteomic analysis of Mgrn1 mutant and control brains was performed to explore the hypothesis that loss of MGRN1 causes neurodegeneration via accumulation of its substrates. Many mitochondrial proteins were reduced in Mgrn1 mutants. Subsequent assays confirmed significantly reduced mitochondrial complex IV expression and activity as well as increased oxidative stress in mutant brains. Mitochondrial dysfunction was obvious many months before onset of vacuolation, implicating this as a causative factor. Compatible with the hypothesis that ATRN and MGRN1 act in the same pathway, mitochondrial dysfunction and increased oxidative stress were also observed in the brains of Atrn mutants. Our results suggest that the study of Mgrn1 and Atrn mutant mice will provide insight into a causative molecular mechanism common to many neurodegenerative disorders.

[Application of fourier transform infrared spectroscopy to non-invasive detection of pleomorphic adenoma of salivary gland in vivo].

In the present work, 20 patients with salivary pleomorphic adenoma were recruited for FTIR spectroscopic measurement. These obtained FTIR spectra were analyzed and compared. It was found that there were significant differences in the spectral features of the skin covering normal salivary gland, pleomorphic adenoma, and carcinoma change of pleomorphic adenoma, such as the changes in peak position, band shape and relative intensity of the bands in the ranges of 1000-1800 cm(-1) and 2800-3000 cm(-1). Pathological diagnosis demonstrated that 2 of the 20 patients suffered actually carcinoma change of pleomorphic adenoma, which is in good agreement with the result of FTIR spectroscopicmeasurement. FTIR spectroscopic m ethodsuggested that pleomorphic adenoma is the intermediate between normal salivary gland and carcinoma change of pleomorphic adenoma.

Characteristics of benign lymphoadenosis of oral mucosa.

AIM: To investigate the pathological characteristics and carcinogenesis mechanism of benign lymphoadenosis of oral mucosa (BLOM). METHODS: The expressions of Ki-67, CD34 and apoptosis were evaluated by immunohistochemical SP staining in 64 paraffin-embedded tissue samples. Of them, 9 were from BLOM with dysplasia, 15 from BLOM without dysplasia, 15 from oral squamous cell carcinoma (OSCC), 15 from oral precancerosis, and 10 from normal tissues. Cell proliferation, apoptosis and angiogenesis of tissue samples were also analyzed. RESULTS: The expression of Ki-67 in BLOM with dysplasia, oral precancerosis and OSCC was significantly higher than in BLOM without dysplasia and normal mucosa. The microvascular density (MVD) in BLOM with and without dysplasia, oral precancerosis, and OSCC was significantly higher than in normal mucosa. Apoptosis in BLOM and oral precancerosis was significantly higher than in OSCC and normal mucosa. CONCLUSION: Benign lymphoadenosis of oral mucosa has potentialities of cancerization.

[Senile chronic submandibular sialadenitis].

OBJECTIVE: To evaluate the clinic characteristic and treatment of senile chronic submandibular sialadenitis. METHODS: The clinical records of the patients over 50 years old whose final diagnosis was chronic submandibular sialadenitis were reviewed. The patients were diagnosed as neoplasm of submandibular gland before operation, There was no radiographic sign of sialolithiasis, no clinical and laboratory signs of Sjögren syndrome or related autoimmune disease. RESULTS: Thirty-five patients were presented in masses in the submandibular space, which was not related to eating. Histopathologic study showed destruction of acinus, infiltration of inflammatory cell, and micro-calcification in the intercalated duct. CONCLUSIONS: The diagnosis of senile chronic submandibular sialadenitis should be considered if a mass in the submandibular space occurs in the old patients and radiographic study shows no sialolithiasis and neoplasm. Resection of the submandibular gland is not necessary for these patients.

[Immunohistochemical study of benign lymphoadenosis of oral mucosa].

OBJECTIVE: To study the expression of Ki-67 and the changes of MVD and apoptosis in benign lymphoadenosis of oral mucosa (BLOM). METHODS: The expression of Ki-67, CD34 and apoptosis were evaluated by SP immunohistochemical staining in 15 BLOM, 9 BLOM with dysplasia, 15 oral squamous cell carcinoma (OSCC). RESULTS: The expression of Ki-67 in BOLM with dysplasia and OSCC was significantly higher than that of BLOM without dysplasia and normal oral mucosa (P < 0.05). The MVD in all BLOM and OSCC was significantly higher than that in normal mucosa (P < 0.05). Apoptosis in BLOM was higher than in normal mucosa and OSCC (P < 0.05). CONCLUSIONS: The expression of Ki-67 and MVD in BLOM with dysplasia were between normal oral mucosa and oral carcinoma. The occurrence of apoptosis in BLOM was significantly higher than in normal oral mucosa. The results suggest that BLOM had the potentiality of malignant transformation.

[Gene expression and pathological changes of rat submandibular glands after adenovirus-mediated gene transfer].

OBJECTIVE: To investigate luciferase gene expression and pathological changes of submandibular glands (SMG) of rats after adenovirus-mediated gene transfer. METHODS: Adenovirus-mediated luciferase gene (AdCMVLuc, 10(8) pfu in 50 microl) was injected in to SMG of forty wistar rats. The SMGs were harvested for gene expression measurement and pathological study after 3 days, 1,2,4 and 8 weeks. RESULTS: Peak expression was observed in three days following administration of the vector however, gene expression in submandibular glands decreased rapidly. the pathological changes induced by retrograde injection of AdCMVLuc included: after 3 days to one week, compression of acini, dilation of terminal ducts; after two weeks, slight atrophy of a part of acini, increase of iteracinar distance and focal lymphocyte infiltration in lobules and interlobular ducts; after 4 weeks, recovery evidence was found in acini; after 8 weeks, normal acini and ducts were found. The ultrastructural changes included: 3 days, much more rough endoplasmic reticulum was found both in acini and duct epithelial cell; a lot of mucus drops were found in acini; after 1 week, microvillus decreased in duct epithelial cells, mitochondria increased significantly in acini; intercellular space was enlarged. CONCLUSIONS: Adenovirus-mediated gene transfer can produce biological proteins and induce marked inflammatory changes in rat SMG. The ultrastructural changes suggest high protein synthesis activity in the acinar cells after gene transfer.

Myoepithelial carcinoma of the salivary glands: behavior and management.

OBJECTIVE: To investigate the biological behavior and proper management of myoepithelial carcinomas of salivary glands. METHODS: Twenty-seven cases of myoepithelial carcinoma of salivary glands were retrospectively studied and their detailed clinical and follow-up data were presented. RESULTS: The subjects consisted of 17 men and 10 women aged 16 to 73 years (mean age: 51 years). The parotid gland was the most common site (n = 14) of cancer. Clinical features included extensive local growth, invasion of the surrounding tissues, infrequent cervical lymph node metastasis but high rates of distant metastasis, frequent/multiple recurrences and poor prognosis. CONCLUSIONS: Myoepithelial carcinomas of the salivary gland should be classified as high-grade malignancies. Early and radical surgery with close follow-up are essential for achieving favorable outcomes. Radiotherapy appears to be non-sensitive and elective neck dissection is generally unnecessary.

Mucinous adenocarcinoma of salivary glands.

OBJECTIVE: To investigate the clinicopathological features of mucinous adenocarcinoma of salivary glands. METHODS: The clinical manifestations and histopathological characteristics of 6 cases of mucinous adenocarcinoma of salivary gland were studied by retrospective and routine histopathology and immunohistochemistry. RESULTS: Four mucinous adenocarcinoma occurred in palate and 2 in mouth floor. Average age of patients was 60 years (48 - 70) and males were affected more often than females (4:2). Pathologically, the tumor grew with infiltration of surrounding tissues. The tumor consisted of unitary mucinous cells and mucin pool was obvious. The cell pleomorphism and nuclear mitosis were often seen. Some tumors showed acinus-like structure. Tumor cells often formed incomplete duct-like structure and small clusters floating in mucinous pool. There were intracellular mucin and signet ring cells in the tumor. Tumor cells showed positive reaction to PAS, Alcin blue, and some cytokeratin staining. CONCLUSIONS: Mucinous adenocarcinoma of salivary gland is a rare malignant tumor which mainly affects palate and mouth floor of older patients. The tumor may originate from acinic cell of mucous acinus or multi-potential cell of salivary gland.

[A clinical and histological study of Bio-Oss in combination with guided bone regeneration membrane technique].

OBJECTIVE: To evaluate the reliability of Bio-Oss particles as bone grafts in combination with membrane-technique. METHODS: 6 small biopsy specimens were retrieved without causing iatrogenic damage in 6 patients (implant sites). The Donath's hard tissue section and micro grinding technique was adopted, and Leval Laczko staining method was used. RESULTS: The histological results showed Bio-Oss particles were easily distinguished from the newly formed bone, but new bone was formed among different particles of Bio-Oss, no connective tissue was found. Intimate contact between newly formed bone and particles of the graft was present. CONCLUSIONS: Bio-Oss appears to be highly biocompatible and osteoconductive. It can be used success fully as a bone substitute in combination with guided bone regeneration membrane technique.

[FTIR microspectroscopic investigation on the stained and unstained histotomic section of oral tissues].

In this paper, stained and unstained samples of oral tissues have been investigated using FT-microspectroscopy. The experimental results demonstrated that staining did not influence the characteristic features of the FTIR spectra of the oral tissues, thereby providing abundant opportunity of further understanding of the structural-spectral relationship of normal and malignant tissues.

Ultrastructural changes of TMJ articular cartilage and synovial membrane following occlusal trauma in rabbit.

OBJECTIVE: To study the effects of occlusal trauma on the ultra-structure of synovial membrane and articular cartilage in rabbit's temporomandibular joints (TMJ). METHODS: TMJs from six rabbits with occlusal trauma and three control rabbits were studied by transmission electron microscopy. RESULTS: Degenerative changes in synovial membrane and articular cartilage of TMJ were induced following occlusal trauma. The structure of the articular surface was damaged, and chondrocytes in cartilage showed signs of degeneration. The synovial lining cells contained dense accumulations of vimentin intermediate filaments (IFs), which were especially prevalent in the cellular processes as well as paranuclearly. Microvilli on the synovial cell membrane were commonly seen. The "vermiform bodies" in the deeper interstitium of the synovial tissue were also found. Our findings of the punctate adherens between synovial lining cells were described in detail. CONCLUSIONS: The occlusal trauma is really a factor inducing degenerative changes of the TMJ.