Microstructure and innervation of the mystacial vibrissal follicle-sinus complex in bearded seals, Erignathus barbatus (Pinnipedia: Phocidae)

Vibrissal follicle-sinus complexes (F-SCs) are sensory receptors of the mammalian integument system. They are best developed within Pinnipedia. The objective of this study was to investigate the F-SCs of bearded seals (Erignathus barbatus) for benthic foraging adaptations. Bearded seals possessed approximately 244 mystacial F-SCs. In this species, F-SCs consisted of an outer dermal capsule (DC) surrounding a blood sinus system [upper cavernous sinus (UCS), ring sinus (RS), and lower cavernous sinus (LCS)] and concentric rings of epidermal tissue. The UCS comprised up to 62% of the F-SC length and may function as thermal protection for mechanoreceptors. A large asymmetrical ringwulst was located in the RS. A deep vibrissal nerve penetrated the DC at its base and terminated on mechanoreceptors in the epidermal tissues of the LCS and RS. The mean number of myelinated axons per F-SC was 1,314 (range, 811-1,650) and was among the highest number of axons per F-SC reported to date. An estimated mean number of 320,616 myelinated axons innervate the entire mystacial vibrissal array. Merkel-Neurite complexes (MNCs) and small simple laminated corpuscles were found in the region of the LCS. Myelinated axons also terminated on MNCs and lanceolate endings apical to the ringwulst. The number of F-SCs, their geometry in the mystacial region, the number of myelinated axons per F-SC, and the distribution of mechanoreceptors support the premise that pinniped vibrissae are sensitive active-touch receptor systems, and that structural differences in bearded seals, relative to other phocids, may be adaptations for benthic foraging.     

Deformation-corrected computer-aided three-dimensional reconstruction of immunohistochemically stained organs: application to the rat heart during early organogenesis

The application of a computer-assisted, three-dimensional reconstruction procedure for serial sections to embryonic rat hearts during the period of cardiac looping and compartmentalization is described. The procedure relies on immunohistochemical staining for the introduction of selective contrast and on episcopic and diascopic images of each of the sections for alignment and correction of compression due to sectioning. Episcopic (reference) images are taken from the embedding block just before the cutting of a slice and are still aligned and undeformed. Diascopic images are taken from the sections after immunohistochemical processing and, hence, contain selective contrast but are deformed and no longer aligned. The three-dimensional images are visualized as shaded voxel models. This approach allowed the unequivocal delineation of the developing myocardium and the inspection of its changing architecture both from the outside and from within. Furthermore, it allowed a quantification of myocardial volume. Because standardized and hence comparable views of three different stages were generated, changes in the shape of the cardiac loop, the atria, and the ventricles as well as changes in the position of the atrioventricular canal and interventricular foramen could be accurately described. Characteristic changes in the position of both the right ventricle and the atrioventricular canal that are essential for the formation of a correctly functioning four-chambered heart could be observed. These changes in shape occur while the myocardial size increases dramatically.     

Somatotopic organization of vibrissal responses in the ventro-basal complex of the rat thalamus

1. The region of the ventro-basal complex (VB) of the thalamus responding to movements of the whiskers has been mapped electrophysiologically in rats under either urethane or barbiturate anaesthesia.

2. Whisker responses were found in the dorso-medial part of VB throughout its rostro-caudal extent; they occupied one third to one half of the total VB region.

3. Most cells responded to movements of only one whisker and the responses were somatotopically organized. The different horizontal lines of whiskers were represented at different rostro-caudal levels within the nucleus, the most dorsal line being represented most caudally. At each level the larger, more caudal whiskers were represented more dorsally and laterally than the smaller, more rostral whiskers.

     

三维CT精确重建颅颌面部组织的形态学特征

背景：头影测量技术是正畸术前临床诊断与矫治计划设计的重要手段,精确的头影测量可为矫治设计提供可靠的依据。三维CT重建技术可重建出清晰、立体、真实的颅颌面解剖形态。 目的：综述CT三维重建后的头影测量在口腔正畸中的临床应用,并与传统的X射线头影测量对比。 方法：由第一作者于2010-09进行检索,检索PubMed数据库(http://www.ncbi.nlm.nih.gov/pubmed/)及CNKI数据库(http://dlib3.cnki.net/KNS50/)1996-01/2010-09有关正畸头影测量的文献,英文以“three-dimensional cephalometry,cephalometric measurements”为检索词,中文以“三维测量,头影测量”为检索词,排除重复研究或内容较陈旧的文献。 结果与结论：计算机初步检索文献共114篇,根据纳入、排除标准,最后选择中英文文献共27篇进一步分析。三维CT重建头影测量技术作为一种理想的头影测量方法,以其高效、准确、快捷的优点,已广泛应用于临床。软硬组织的三维立体重建与测量分析系统以其强大的优势,终将取代现有的二维头影测量分析系统。     

The morphology of neurons in rat tectal transplants as revealed by Golgi-Cox impregnation

Summary The Golgi technique has been used to examine the morphology of neurons within tectal transplants. Embryonic tectal tissue was transplanted to the midbrain of newborn rats. Four to eight months later, host animals were decapitated under anaesthesia, the unfixed brains removed and processed by Golgi-Cox impregnation. In tectal grafts, different types of neuron were recognized on the basis of the size and shape of their somata and the morphology of their dendritic trees. Neuronal types found in transplants resembled cell classes found in normal rat superior colliculus (SC). Neurons characteristic of the superficial collicular layers such as marginal, ganglion type I, stellate and horizontal cells and multipolar cells typical of the deeper collicular layers were identified in the transplants. Compared with normal cells, grafted neurons often had smaller dendritic fields and fewer dendritic spines. No laminar organization was discernable in the grafts and there was commonly no preferential orientation of perikarya or dendrites. Small cells with similar dendritic morphology were sometimes found grouped together in patches within the graft neuropil. These patches resembled cytologically and histochemically distinct areas described in previous studies and may represent areas homologous to the superficial layers of normal SC.     

Quantitative assessment of the rat intrahepatic biliary system by three-dimensional reconstruction

The anatomical details of the biliary tree architecture of normal rats and rats in whom selective proliferation was induced by feeding alpha-naphthylisothiocyanate (ANIT) were reconstructed in three dimension using a microscopic-computed tomography scanner. The intrahepatic biliary tree was filled with a silicone polymer through the common bile duct and each liver lobe embedded in Bioplastic; specimens were then scanned by a microscopic-computed tomography scanner and modified Feldkamp cone beam backprojection algorithm applied to generate three-dimensional images. Quantitative analysis of bile duct geometry was performed using a customized software program. The diameter of the bile duct segments of normal and ANIT-fed rats progressively decreased with increasing length of the biliary tree. Diameter of bile ducts from ANIT-fed rats (range, 21 to 264 microm) was similar to that of normal rats (22 to 279 microm). In contrast, the number of bile duct segments along the major branch reproducibly doubled, the length of the bile duct segments decreased twofold, and the length of the biliary tree remained unchanged after ANIT feeding. Moreover, the total volume of the biliary tree of ANIT-fed rats was significantly greater (855 microl) than in normal rats (47 microl). Compared with normal rats, the total surface area of the biliary tree increased 26 times after ANIT-induced bile duct proliferation. Taken together, these observations quantitate the anatomical remodeling after selective cholangiocyte proliferation and strongly suggest that the proliferative process involves sprouting of new side branches. Our results may be relevant to the mechanisms by which ducts proliferate in response to hepatic injury and to the hypercholeresis that occurs after experimentally induced bile duct proliferation.     

The three-dimensional architecture of vasa vasorum in the wall of the human aorta. A computer-aided reconstruction study

The three-dimensional architecture of vasa vasorum in the wall of aorta was studied by microcomputer-aided reconstruction from serial sections of wall tissue in two young individuals submitted to autopsy. The outer media was sparsely penetrated by special tunnels containing an arteriole and a venule, which we termed a "vascular cord" due to the broad space between neighboring cords that contained no capillary network whatsoever. A dense venular plexus was found extending along the outer surface of the media, forming a plane of low blood pressure. This characteristic pattern of vasculature appeared to provide an important basis on which to study the way the medial tissues are sustained.     

Spatial segregation within the sacral parasympathetic nucleus of neurons innervating the bladder or the penis of the rat as revealed by three-dimensional reconstruction

The purpose of the present investigations was (1) to examine the spatial organization of preganglionic neurons of the sacral parasympathetic nucleus in the lumbosacral spinal cord of male adult rats and (2) to search, in this nucleus, for a possible segregation of sub-populations of neurons innervating the penis or the bladder, respectively. To estimate their spatial organization, neurons of the sacral parasympathetic nucleus were retrogradely labeled by wheat germ agglutinin coupled to horseradish peroxidase applied to the central end of the sectioned pelvic nerve. The sub-populations of lumbosacral neurons innervating the corpus cavernosum of the penis or the dome of the bladder were identified using transsynaptic retrograde labeling by pseudorabies virus injected into these organs in different rats. In both wheat germ agglutinin-labeled and pseudorabies virus-labeled rats, serial coronal sections were cut through the spinal L5-S1 segments. Labeled neurons were revealed by histochemistry (peroxidase experiments) or immunohistochemistry (pseudorabies virus experiments). By means of a three-dimensional reconstruction software developed in our laboratory, three-dimensional models were calculated from each spinal section image series. They revealed the spatial organization of (i) preganglionic neurons and (ii) neurons innervating the bladder or the penis. The different three-dimensional models were subsequently merged into a single one which revealed the segregation, within the sacral parasympathetic nucleus, of the sub-populations of neurons. Neurons labeled by virus injected into the penis extended predominantly from the rostral part of the L6 segment to the rostral part of the S1 segment while those labeled by bladder injections were distributed predominantly from the caudal part of the L6 segment to the caudal part of the S1 segment.These results support the hypothesis of a viscerotopic organization of sacral neurons providing the spinal control of pelvic organs.     

The three-dimensional microvascular arrangement around rat vibrissa hairs as revealed by scanning electron microscopy

The three-dimensional microvascular arrangement around the vibrissa hairs in vascular corrosion casts of adult Wistar rats was studied by scanning electron microscopy. Each hairshaft was surrounded by the sinus, which consisted of the superficial ring sinus and the deeper cavernous sinus. Many trabeculae existed in the cavernous sinus but not in the ring sinus. The hairshaft within the cavernous sinus was surrounded by a basket-like capillary network which was denser at its lower part. On the inside of the ring sinus, only a few arterioles ascended along the hairshaft. Our results indicate that the lower part of the vibrissa hair, which is the most important area for hair growth, is supplied with a more abundant blood supply and is protected from external forces by the cavernous sinus with its many trabeculae. This study was presented at the 25th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Matsumoto, September 28–30, 1993.     

The three-dimensional microvascular arrangement around rat dorsal hairs as revealed by scanning electron microscopy

The three-dimensional microvascular arrangement around the dorsal hairs in vascular corrosion casts of adult Wistar rats was studied by scanning electron microscopy. Each anagen dorsal hair was surrounded by a basket-like capillary network, which was supplied by the branches of the subcutaneous artery and drained into the veins continuous with the subcutaneous vein. The capillary network surrounding the anagen dorsal hair was denser at its lower part, and became more sparse at its upper part. Transmission electron microscopy showed that the capillaries around the hair bulb possessed fenestrations. Our findings indicate that the microvascular arrangement around the anagen dorsal hair is so organized as to supply the hair bulb, which is the most important area for hair growth, with abundant blood. This study was presented at the 24th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Okayama, September 17–19, 1992.     

Input-output organization of the rat vibrissal motor cortex

The afferent and efferent connections of the vibrissal area of the rat motor cortex (VMCx) were investigated by injecting Phaseolus vulgaris leucoagglutinin (PHA-L) or wheat germ agglutinin-horseradish peroxidase into the physiologically defined VMCx. The VMCx formed reciprocal connections with the primary and secondary somatosensory cortex, lateral and ventrolateral orbital cortex, retrosplenial cortex, and perirhinal cortex. These corticocortical afferents originated from cell bodies in layers II–III and V, and some afferents originated from cell bodies in layer VI of the primary sensory cortex. All of the VMCx efferents terminated in layers I and V or layers I–III and V. The VMCx also formed reciprocal connections with the ventrolateral, ventromedial and centrolateral nucleus, the lateral portion of the mediodorsal nucleus and the posterior complex of the thalamus. It projected bilaterally to the caudate putamen, primarily ipsilaterally to the superior colliculus, anterior pretectal nucleus, and pontine nucleus, and mainly contralaterally to the oral part of the spinotrigeminal nucleus and the reticular formation around the facial nerve nucleus. Finally, injections of PHA-L into the superior colliculus demonstrated that this structure projected contralaterally to the lateral part of the facial nerve nucleus. These data suggest that the VMCx plays a key role in sensorimotor integration, through its extensive interconnectivity with numerous brain structures, and may modulate orientation behaviors by relaying processed information to the superior colliculus.     

SpineLab: tool for three-dimensional reconstruction of neuronal cell morphology

SpineLab is a software tool developed for reconstructing neuronal feature skeletons from three-dimensional single- or multi-photon image stacks. These images often suffer from limited resolution and a low signal-to-noise ratio, making the extraction of morphometric information difficult. To overcome this limitation, we have developed a software tool that offers the possibility to create feature skeletons in various modes-automatically as well as with manual interaction. We have named this novel tool SpineLab. In a first step, an investigator adjusts a set of parameters for automatic analysis in an interactive manner, i.e., with online visual feedback, followed by a second step, in which the neuronal feature skeleton can be modified by hand. We validate the ability of SpineLab to reconstruct the entire dendritic tree of identified GFP-expressing neurons and evaluate the accuracy of dendritic spine detection. We report that SpineLab is capable of significantly facilitating the reconstruction of dendrites and spines. Moreover, the automatic approach appears sufficient to detect spine density changes in time-lapse imaging experiments. Taken together, we conclude that SpineLab is an ideal software tool for partially automatic reconstruction of neural cell morphology.     

复杂胸椎骨折中CT图像三维重建的应用探讨

目的直观立体地显示复杂胸椎骨折的图像，探讨螺旋CT医学图像三维重建在复杂胸椎骨折诊断中的价值及其对手术的指导意义。方法对92例胸椎骨折患者采用螺旋CT进行薄层扫描和三维重建进行诊断。CT扫描全部采用Siemens SOMATOM Sensation16型多排高速螺旋CT机，1．0mm层厚。扫猫所得断层资料通过网络传送至计算机工作站进行处理，采用Window．NT3．51平台上Insisht三维重建软件进行三维重建。结果三维CT图像能够围绕X轴和Z轴任意旋转、切割以从不同角度观察，能够清晰显示复杂的胸椎骨折和狭窄椎管的解剖形态特点。结论三维CT重建在胸椎骨折方面具有很大的临床应用价值，有助于提高脊柱骨折手术的安全性和精确性并对患者预后的估计提供帮助。     

Automatic identification of biological microorganisms using three-dimensional complex morphology

We propose automated identification of microorganisms using three-dimensional (3-D) complex morphology. This 3-D complex morphology pattern includes the complex amplitude (magnitude and phase) of computationally reconstructed holographic images at arbitrary depths. Microscope-based single-exposure on-line (SEOL) digital holography records and reconstructs holographic images of the biological microorganisms. The 3-D automatic recognition is processed by segmentation, feature extraction by Gabor-based wavelets, automatic feature vector selection by graph matching, training rules, and a decision process. Graph matching combined with Gabor feature vectors measures the similarity of complex geometrical shapes between a reference microorganism and unknown biological samples. Automatic selection of the training data is proposed to achieve a fully automatic recognition system. Preliminary experimental results are presented for 3-D image recognition of Sphacelaria alga and Tribonema aequale alga.     

Biomechanical models for radial distance determination by the rat vibrissal system

Rats use active, rhythmic movements of their whiskers to acquire tactile information about three-dimensional object features. There are no receptors along the length of the whisker; therefore all tactile information must be mechanically transduced back to receptors at the whisker base. This raises the question: how might the rat determine the radial contact position of an object along the whisker? We developed two complementary biomechanical models that show that the rat could determine radial object distance by monitoring the rate of change of moment (or equivalently, the rate of change of curvature) at the whisker base. The first model is used to explore the effects of taper and inherent whisker curvature on whisker deformation and used to predict the shapes of real rat whiskers during deflections at different radial distances. Predicted shapes closely matched experimental measurements. The second model describes the relationship between radial object distance and the rate of change of moment at the base of a tapered, inherently curved whisker. Together, these models can account for recent recordings showing that some trigeminal ganglion (Vg) neurons encode closer radial distances with increased firing rates. The models also suggest that four and only four physical variables at the whisker base -- angular position, angular velocity, moment, and rate of change of moment -- are needed to describe the dynamic state of a whisker. We interpret these results in the context of our evolving hypothesis that neural responses in Vg can be represented using a state-encoding scheme that includes combinations of these four variables.     

The three-dimensional microvascular and collagen fibrillar arrangements around rat vibrissa hairs as revealed by scanning electron microscopy

The three-dimensional microvascular and collagen fibrillar arrangements around the vibrissa hairs of adult Wistar rats were studied by scanning electron microscopy. Each hair root was surrounded by the sinus, which consisted of the superficial ring sinus and the deeper cavernous sinus. Many trabeculae existed in the cavernous sinus but not in the ring sinus. The hair root within the cavernous sinus was surrounded by a basket-like capillary network which was denser at its lower part. The capillary network surrounding the lower part of the hair root was supplied by the radical artery and drained into the radical vein, while that surrounding the upper part of the hair root was supplied by the subcapsular artery and drained into the subcapsular vein. On the inside of the ring sinus, only a few arterioles ascended along the hair root and gave rise to the capillaries which were located below the epidermis. Our findings indicate that the lower part of the vibrissa hair, which is the most important area for hair growth, receives a more abundant blood supply than the upper part and is protected from external forces by the cavernous sinus with its many trabeculae. A part of this study was presented at the 25th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Matsumoto, September 28–30, 1993, and published as a short report in Medical Electron Microscopy, Vol. 27, No. 1.     

The three-dimensional ultrastructure of diabetic glomeruli revealed by the quick-freezing and deep-etching method

The three-dimensional ultrastructure of the glomerular basement membrane (GBM) and mesangial matrix (MM) in streptozotocin (STZ)-induced diabetic rats and in one case of a human diabetic nephropathy were examined using the quick-freezing and deep-etching method. In the diabetic rats, the GBM inner layer was diffusely enlarged, and the meshwork structures in the GBM middle layer and the MM were markedly irregular due to the rupturing of fine fibrils. These irregularities and enlargements of the mesh pores in the diabetic rats developed during the experimental period and were significantly different from those in the control rats. Insulin treatment after STZ injection significantly prevented ultrastructural changes in the GBM and MM. The human diabetic case was a 69-year-old male who had been suffering from non-insulin dependent diabetes mellitus for 29 years. He had a background diabetic retinopathy, microalbuminuria and a decrease in lower limb tendon reflexes. Conventional electron microscopy revealed electron-lucent areas in enlarged subendothelial spaces and mesangium. By the quick-freezing and deep-etching method, the GBM inner layer was diffusely enlarged, and the meshwork structure of the GBM middle layer and the MM showed marked irregularity due to the rupturing of fine fibrils. These findings suggest that the initial morphological changes in diabetic nephropathy include structural abnormalities of fine fibrils in the GBM and MM, which may correspond to the subendothelial and mesangial electron-lucent areas as observed in conventional ultrathin sections.     

Neural substrates of two different rhythmical vibrissal movements in the rat

Normal rats show two types of rhythmical vibrissal movement, one synchronized precisely with alpha waves (about 9 Hz) of the thalamocortical system, and the other often synchronized with theta waves (about 7 Hz) of the septohippocampal system. The alpha-synchronized vibrissal movements appear while the rat stands still with a slow respiratory pattern, and are of small amplitude (a fine tremor). The theta-synchronized vibrissal movements appear during exploratory sniffing behavior, and are of large amplitude. Thus, a group of facial motoneurons which constitute the final common pathway for vibrissal movement apparently receive input convergently from these two neural systems. In the present study, we observed the following: (1) the two types of movement rarely, if ever, appeared simultaneously and the same was true of the two brain wave patterns. Topographically, the predominant appearance of the alpha waves was in the frontal (sensorimotor) cortex, whereas that of the theta waves was in the occipital cortex and hippocampus. (2) Bilateral ablation of either the entire neocortex or just its anterior (but not posterior) half eliminated the vibrissal alpha-tremor movement while leaving vibrissal theta-sniffing movement normal. In anterior decorticate rats, the tremor movements started to recover by 1-4 months, and were abolished again by the removal of the remaining posterior cortex. (3) Lesions of the medial septum or the fornix eliminated hippocampal theta waves, but had no effect on vibrissal sniffing movement or alpha wave-vibrissal tremor. (4) Cerebellectomy and, to a lesser extent, pharmacological lesions of the inferior olive slowed, but did not block, alpha waves. In addition, vibrissal tremor movement became intermittent and less vigorous. The same manipulations, however, did not affect theta wave-vibrissal sniffing movement. (5) Harmaline (30 mg/kg, i.p.) did not induce alpha-tremor, which, in combination with the results with cerebellectomy and inferior olive lesions, indicates that alpha-tremor is generated by a neural mechanism that is different from that for harmaline-induced generalized tremor of 10 Hz. These findings confirmed that there exist two patterns of synchrony between vibrissal movement and rhythmical brain activity in the rat, i.e. alpha wave-vibrissal tremor movement and theta wave-vibrissal sniffing movement, and suggest that the two patterns reflect a rhythmical mode of functioning of two different neural systems, probably the thalamocortical and the septohippocampal system, respectively.