Correlation of MRT imaging with real-time axiography of TMJ clicks

There is a series of tools useful for gathering diagnostic information on patients with temporomandibular joint disorders. Tracings of the joint movement (axiography) provide useful information about the motion of the joints. Since the availability of electronic axiographic tracers, the movement of the condyles can be resolved with high resolution both in space and in time. In order to obtain information about the anatomical relation of the joint surfaces and the disc, magnetic resonance tomography imaging (MRI) is routinely carried out. It is common practice to take MR images of the joints with the mouth closed and fully open. In order to correlate the MR images with the axiographic tracings, a series of images can provide much more information. In this study we examined patients with distinct temporomandibular joint (TMJ) clicks. In one case, the click occurs once a day, while in the other case the click happens every time the mouth is opened. In order to obtain information about both motion and anatomical relation of the TMJ at and around the position where the clicks occur, we recorded a series of MRI scans with the mouth gradually opened and before and after joint clicks. Real-time axiographic tracings during the click were taken with an optimized system where the polar moments were reduced as much as possible to follow the movement during the click. These tracings were correlated with the MRI scans to determine the exact internal conditions of the TMJ and the changes during the click. In particular cases, the additional information provided by this procedure can be useful in deciding whether and which therapeutic intervention is advisable.     

Human and rodent humoral immune responses to Andes virus structural proteins

In the present work we identified B-cell epitopes recognized by sera of humans and rodents naturally infected with Andes virus, a hantavirus present in Chile and Argentina. Analysis of patient and rodent sera with overlapping peptides revealed 21 human and rodent epitopes on the three structural proteins. Whereas in the nucleoprotein the region comprising aa 248-260 was shown to be the key determinant of human sera, the major antigenic site of rodent antibody reactivity is located at aa 326-338. In G1, the main epitope recognized by human sera was mapped to aa 14-26, while rodent antibodies bound predominantly to aa 599-611. In contrast, humans and mice had strong responses to three regions in G2 (aa 691-703, aa 918-930, aa 955-967), of which the last two are associated with neutralization of Hantaan virus. This insight affords important information for the development of immunotherapies for the acute phase of hantavirus cardiopulmonary syndrome.     

生物软组织力学特性的研究进展

本文对生物软组织力学本构关系的研究进展进行了综述,内容涉及肌肉、韧带、肌腱、皮肤、粘膜、血管、腔体器官(如眼球)等领域.     

Microvascular structural entropy: A novel approach to assess angiogenesis in pituitary tumors

Entropy, a measure of the degree of disorder in a system, has recently been used in different morphologic studies to quantify regularity. Our aims were (a) to study the structural organization of the microvascular bed in prolactin (PRL)-producing adenomas and carcinomas, the most vascularized of pituitary tumors, by assessing microvascular structural entropy (MSE), and (b) to determine whether the degree of disorder of the capillary bed correlates with tumor cell proliferation as estimated by MIB-1 labeling, microvessel density (MVD), the most widely used method of quantifying blood vessel formation, and various clinicopathologic parameters (gender, age, tumor size and invasiveness). The morphometric study demonstrated statistically significant differences in MIB-1 labeling, MVD, and MSE between PRL-producing adenomas and carcinomas. Unlike MIB-1 labeling index (PRL-producing adenomas 1.5±0.27; carcinomas 15.0±4.04) and MVD (PRL-producing adenomas 2.7±0.34; carcinomas 4.2±0.72), the MSE values were significantly higher in adenomas (171.5±25.37) than in carcinomas (67.9±17.45). These results indicate that PRL-producing carcinomas have a less chaotic distribution of vessels than benign adenomas. In contrast to a lack of correlation between, microvessel density and other morphometric parameters, a strong negative correlation was found between MSE and MIB-1 labeling index (r=0.511, p=0.003). It thus appears that regular, less chaotic microvascular geometry contributes to increased proliferative activity in PRL cell tumors. Analysis of MSE may provide an independent parameter of tumor behavior, and contributes to a better understanding of the role of microvasculature in pituitary tumor progression.     

Presence of a linear plasmid-like DNA molecule in the fungal pathogen Ceratocystis fimbriata Ell. & Halst.

Summary A plasmid-like molecule was detected in a strain of the ascomycete Ceratocystis fimbriata Ell. & Halst., a pathogenic fungus of Populus spp. The DNA replicon, designated pFQ501, was found to have a linear structure with a length of 6.0 kb (3.9 × 10⁶ daltons) and a density of 1.685 g/cc. This molecule was found to be associated with the mitochondria and was isolated from the gel; its restriction map was deduced from single and double digestions.     

Alternative common factor models for multivariate biometric analyses

In prior research we have shown how linear structural equation models and computer programs (e.g., LISREL) may be simply and directly used to provide alternatives for the traditional biometric twin design. We use structural equations and path models to define biometric group differences, we write traditional common-factor models in the same way, and then we take a detailed look at some alternative multivariate and biometric models. We contrast the biometricfactors covariance structure approach used by Loehlin and Vandenberg (1968), Martin and Eaves (1977), and others with the psychometric-factors approach used by McArdle et al. (1980) and others. We use the multivariate primary mental abilities data on monozygotic (MZ) and dizygotic (DZ) twins from Loehlin and Vandenberg (1968) to detail fundamental differences in model specification and results. We extend both multivariate biometric approaches using exploratory and confirmatory multiple-factor models. These comparisons show that each alternative multivariate methodology has useful features for empirical applications.This research has been supported by grants from the National Institute on Aging (AG02695, AG04704, and AG07137) to McArdle, and a Research Career Development Award (HD00694) to Goldsmith.     

The vestibulo-ocular reflex in three dimensions

The purpose of this paper is to review the kinematics and dynamics of the vestibulo-ocular reflex (VOR) in three dimensions. We give a brief, didactic tutorial on vectors and matrices and their importance as representational schemes for describing the kinematics and dynamics of the angular and linear accelerations that activate the vestibular system. We show how the vectors associated with angular and linear head accelerations are transformed by the peripheral and central vestibular systems to drive the oculomotor system to produce eye movements in three-dimensional space. We also review critical questions and controversies related to the compensatory and orientation behavior of the VOR. One such question is how the central vestibular system distinguishes tilts of the head, which generate interaural linear acceleration from translations along the interaural axis. Another question is how the velocity-position integrator is implemented centrally. The review has been placed in the context of a model that explains the behavior of the VOR in three dimensions. Model processes have been related to peripheral and central neural behavior in order to gain insight into the nature of the three-dimensional organization and the controversial questions that are addressed.     

Saccular and utricular inputs to single vestibular neurons in cats

Saccular and utricular organs are essential for postural stability and gaze control. Although saccular and utricular inputs are known to terminate on vestibular neurons, few previous studies have precisely elucidated the origin of these inputs. We investigated the saccular and utricular inputs to single vestibular neurons in whole vestibular nuclei of decerebrated cats. Postsynaptic potentials were recorded from vestibular neurons after electrical stimulation of the saccular and utricular nerves. Ascending and descending axonal projections were examined by stimulating the oculomotor/trochlear nuclei and the cervical segment of the spinal cord, respectively. After each experiment, locations of recorded neurons were identified. The recorded neurons (140) were classified into vestibulo-spinal (79), vestibulo-oculo-spinal (9), and vestibulo-ocular (3) neurons based on antidromic responses; 49 other vestibular neurons were unidentified. The majority of recorded neurons were mainly located in the lateral vestibular nucleus. Most of the otolith-activated vestibular nuclei neurons seemed to participate in vestibulospinal reflexes. Of the total 140 neurons recorded, approximately one third (51) received saccular and utricular inputs (convergent neurons). The properties of these 51 convergent neurons were further investigated. Most (33/51) received excitatory postsynaptic potentials (EPSPs) after saccular and utricular nerve stimulation. These results implied that most of the convergent neurons in this study additively coded mixed information for vertical and horizontal linear acceleration. Based on the latencies of convergent neurons, we found that an early integration process for vertical and horizontal linear acceleration existed at the second-order level.     

The terminal protein of a linear mitochondrial plasmid is encoded in the N-terminus of the DNA polymerase gene in white-rot fungus Pleurotus ostreatus

The gene structure and expression of the linear mitochondrial plasmids of the white-rot fungus Pleurotus ostreatus, pMLP1 and pMLP2, were analyzed. Cleavage by proteinase K and exonucleases indicated that the 5′ ends of pMLP1 and pMLP2 DNAs were associated with terminal proteins. Nucleotide sequencing of the entire pMLP1 DNA revealed that it consists of 9,879 bp with terminal inverted repeat (TIR) sequences of 381 bp. The end sequence of TIR in pMLP1 is 3′-CCCCC-5′, similar to those of Escherichia coli phage PRD1. The pMLP1 plasmid harbors two long open reading frames (ORF1 and ORF2) and at least one minor ORF (mORF1). The deduced product of ORF1 is homologous to RNA polymerases of yeast mitochondria and several bacteriophages, whereas that of ORF2 is homologous to the protein-primed DNA polymerases of family B type. The mORF1 encodes a highly basic protein, most likely a TIR-binding protein, with no apparent sequence homology in the database. Expression of the predicted gene products from pMLP1 in mitochondria was demonstrated by Western blot analysis using antibodies against various expressed regions of pMLP1 ORFs. A plasmid-free strain, generated by curing with ethidium bromide, did not express any of these gene products. Terminal proteins of 70 kDa (TP1) and 73 kDa (TP2) were identified from pMLP1 and pMLP2, respectively. Western blot analysis indicated that TP1 was generated from the N-terminal half of the full-length product of ORF2 encoding a putative DNA polymerase. Received: 9 February 2000 / Accepted: 18 July 2000     

胸部体表导纳变化与胸腔中血管导纳变化的关系

目的：探讨胸部体表导纳变化与胸腔中血管导纳变化的关系。方法：根据导纳与阻抗互为倒数的关系，导出胸部体表导纳变化公式，并用模型实验证明。结果：单根血管在胸部体表引起的导纳变化与血管本身的导纳变化和基础导纳的比值成正比，与血管的长度和胸部体表两检测电极之间的基础导纳成正比，与血管到两检测电极连线的距离成反比；多根血管在胸部体表共同引起的导纳变化等于各血管单独在胸部体表产生的导纳变化的代数和，即在电导纳图测量中导纳变化遵从标量迭加原理。结论：本文结果可为心导纳图的波形重建奠定理论基础。