Sensory recovery and Meissner corpuscle number after toe-to-hand transplantation

This study investigated the possible relationship between sensory recovery and receptor number after toe-to-hand transplantation. Moving two-point discrimination was measured after a course of sensory re-education. Meissner corpuscle number was then quantified by light microscopic examination of multiple sections of glabrous skin obtained at pulp reduction and from site-matched normal toe and fingertip skin. Meissner corpuscle number per millimeter was 0.94 in normal toe skin (n = 4), and 0.37 after toe-to-hand transplantation (n = 34). A significant correlation existed between moving two-point discrimination and Meissner corpuscle number (r = -0.62; p < 0.001). No significant relationship was found between moving two-point discrimination and patient age or interval from injury to reconstruction. The results suggest that despite sensory re-education, there may be a level of receptor reinnervation below which good sensory recovery may not be obtained.     

The three-dimensional microanatomy of Meissner corpuscles in monkey palmar skin

The Meissner corpuscle is a rapidly-adapting mechanoreceptor in the dermal papillae of digital skin. For an analysis of how the sensory endings detect tissue deformations, an examination of their fine structure and relationships with dermal collagen was carried out in the Japanese monkey, Macaca fuscata, using a combination of three methods: SEM of cell architecture denuded by 6N sodium hydroxide maceration, SEM of collagen networks exposed by a mild alkaline corrosion, and TEM according to a conventional procedure. Observations showed the sensory corpuscles to be represented by a stack of discoid components consisting of flattened axon terminals sandwiched between Schwann cell lamellae, as reported previously. Each corpuscle was entirely covered by a connective tissue capsule, which was linked with the basal aspect of the epidermis by dermal collagen fibers. Margins of the discoid components of the corpuscles were serrated with numerous fine projections of lamellar Schwann cells, which tightly held collagen trabeculae on the inner aspect of the pericorpuscular capsule. Central portions of the discoids, on the other hand, displayed extremely smooth surfaces, which were covered by a thick layer of basal lamina-like matrix. The former portions of the discoids appear susceptible to mechanical deformations of surrounding tissues, while the latter may follow the tissue movements rather slowly because of their indirect linkage with the dermal collagen network. The resulting distortions of the axon endings during dynamic phases of the tissue deformations will be in favor of the generation of rapidly adapting receptor potentials in the sensory corpuscle.     

Ultrastructure of the renal corpuscle of Testudo graeca (Chelonia). A comparison between hibernating and non-hibernating animals

The renal corpuscle of hibernating and non-hibernating Testudo graeca was studied by means of light and electron microscopy. Renal corpuscles are small and have a glomerular architecture similar to that found in other vertebrates with a limited glomerular filtration rate. In hibernating animals, unlike non-hibernating, some morphological changes took place. The cells of the renal corpuscle were densely packed, podocytes and parietal cells showed a marked cytoplasmic vacuolization, there was a highly developed capillary basement membrane and the endothelial and mesangial cells showed abundant dense granules. These morphological features apparently correspond to a vacuolar degeneration. They may also be the morphological basis of the decrease in the glomerular filtration rate observed during this period.     

Fine Structure of Subepithelial “Free” and Corpuscular Trigeminal Nerve Endings in Anterior Hard Palate of the Rat

Axonally transported protein labeled many trigeminal nerve endings in subepithelial regions of the anterior hard palate of the rat. Sensory endings were most numerous in the lamina propria near the tips of the palatal rugae where large connective tissue and epithelial papillae interdigitated. Two kinds of sensory ending were found there: “free” endings, and a variety of corpuscular endings. The “free” sensory endings consisted of bundles of unmyelinated axons separated from the connective tissue by relatively unspecialized Schwann cells covering part or all of their surface and a completely continuous basal lamina; they were commonly found running parallel to the epithelium or near corpuscular endings. The corpuscular sensory endings all had a specialized nerve form, specialized Schwann cells, and axonal fingers projecting into the corpuscular basal lamina or connective tissue. There were at least four distinct types of corpuscular ending: Ruffini-like endings were found among dense collagen bundles, and they had a flattened nerve ending with a flattened Schwann lamella on either side. Meissner endings had an ordered stack of flattened nerve terminals with flattened Schwann cells and much basal lamina within and around the corpuscle. Simple corpuscles were single nerve endings surrounded by several layers of concentric lamellar Schwann processes. Glomerular endings were found in lamina propria papillae or encircling epithelial papillae; they were a tangle of varied neural forms each of which had apposed flattened Schwann cells, and a layer of basal lamina of varied thickness. Fibroblasts often formed incomplete partitions around Meissner and simple corpuscles.

The axoplasm of all kinds of subepithelial sensory endings contained numerous mitochondria and vesicles, as well as occasional multivesicular bodies and lysosomes; the axoplasm of all endings was pale with few microtubules and neurofilaments. The specialized lamellar Schwann cells had much pinocytotic activity. Four kinds of junctions were found between the corpuscular sensory endings and the lamellar Schwann cells: (1) symmetric densities that resemble desmosomes; (2) asymmetric densities with either the neuronal or glial membrane more dense; (3) neural membrane densities adjacent to Schwann parallel inner and outer membrane densities; and (4) sites of apparent Schwann endocytosis associated with neural blebs. The “free” sensory endings only made occasional desmosome-like junctions with their Schwann cells.

These observations are discussed in relation to possible mechanosensory transduction mechanisms, with particular attention to axoplasmic structure, axonal fingers, and neural and nonneural cell associations.     

Topography, architecture and structure of the plexus submucosus internus (Meissner) of the porcine small intestine in scanning electron microscopy

Scanning electron microscopy of whole-mount preparations of the tela submucosa in the porcine small intestine, examined after trypsin digestion, fixation and HCl hydrolysis, visualized a clear differentiation of the submucosal plexuses, i.e., the plexus submucosus internus (Meissner) and the plexus submucosus externus (Schabadasch). The distinctive features refer to the topography, number, size and shape of the ganglia and the number and diameter of the nerve strands. The plexus of Meissner is closely apposed to the external surface of the lamina muscularis mucosae by the enveloping connective tissue and by connecting strands penetrating the lamina muscularis mucosae. Three distinctive subdivisions of connecting strands can be identified. Since the glial cells covering the ganglia and connecting strands have been preserved, neither individual neuronal cells nor axons can be observed.     

中华花龟五种器官组织学观察

利用石蜡切片法对中华花龟的心脏、肝脏、脾脏、肺和肾脏等组织器官进行了组织学观察.结果显示心肌的特点是暗带较窄,心肌纤维束状排列.肝脏分3叶,肝实质内结缔组织少,肝小叶分界不清楚.脾脏分被膜和实质两部分,实质由白髓和红髓构成,白髓包括椭球周围淋巴鞘(PELS)和动脉周围淋巴鞘(PALS),红髓由脾索和脾窦组成,未发现淋巴小结和生发中心.肺一对,为长形扁平囊,肺泡囊状,肺泡内可见管壁的结节状膨大.肾脏由肾小体、颈段、近曲小管、中间段、远曲小管和收集管6部分构成,肾小体由肾小球和肾小囊组成,在肾小体附近可见致密斑样结构.     

Identification of the Ruffini corpuscle in human hairy skin

Summary A Ruffini corpuscle was identified in the dense reticular dermis of the human scalp from a patient with alopecia areata. The corpuscle measured approximately 50 m in diameter. One afferent myelinated axon with a diameter of 4–6 m supplies the corpuscle. Branched axon terminals and the associated Schwann cells tightly envelop parallel bundles of collagen fibrils. Axon terminals evidenced focal swellings, and small finger-like protrusions projected into the endoneural connective tissue. The terminals are characterized by the presence of abundant mitochondria, numerous vesicles, particles of glycogen and electron-opaque lipid material. A thin perineural capsule envelops the bundles of collagen fibrils and associated terminals. The present study provides the first electron-microscopic characterization of a Ruffini corpuscle in human hairy skin.This study was supported in part by the Deutsche ForschungsgemeinschaftSupported in part by U.S. Public Health Service Research Contracts NIDR72-2401 and HD4-2869 and Research Grant HD 11216     

A transduction model of the Meissner corpuscle

I propose a transduction model of the Meissner corpuscle that integrates ideas put forth by Freeman and Johnson and results obtained by Looft. The principal development in the present model is its specification that RA receptor potentials are updated as a linear function of stimulus velocity above baseline; the model thus readily accommodates non-sinusoidal input. It also incorporates modifications to Freeman and Johnson's model proposed by Slavík and Bell, namely a period of refractoriness lasting 1 ms followed by a period of hyperexcitability lasting 13.5 ms. The model is applied to various psychophysical and physiological situations: psychophysical threshold vs. frequency, RA afferent impulse rates vs. intensity, impulse regularity vs. frequency, phase retardation vs. frequency, and responses to non-repeating noise and to complex stimuli. Model output closely matches psychophysical and neurophysiological data. The proposed model thus reliably predicts RA afferent responses to arbitrary stimuli and may facilitate the development of theories relating psychophysical phenomena to their underlying neural representations.     

安南龟肝脏和肾脏的组织学观察

采用常规石蜡切片对安南龟的肝脏和肾脏进行了组织学观察。研究结果发现,肝脏分为3叶,肝实质内结缔组织少。肝脏由无数肝小叶构成,肝小叶分界不清。肝细胞为多角形的腺上皮细胞,细胞核圆球形,位于中央。胆小管沿着肝细胞索向肝小叶四周放射并连成细长的微细管道。肾脏由肾小体、颈段、近曲小管、中间段、远曲小管和收集管6部分构成,肾小体由肾小球和肾小囊组成,在肾小体附近可见致密斑样结构,未见髓袢结构。肾小球由盘曲的毛细血管构成。肾小囊是肾小管的起始端,由内、外两层壁层构成,内层与肾小球的毛细血管紧贴,外层为单层扁平上皮细胞。     

Glycosaminoglycans in the touch corpuscle of the dog

Synopsis Alcian Blue staining of the touch corpuscle of dog skin indicates that glycosaminoglycans are present as globular masses in some of the basal cells and are also seen in high concentration in the connective tissue core. The function of these basal cells is not clear but they may be responsible for the production of the large amount of glycosaminoglycan present in the underlying dermis.     

End-to-end linkage (EEL) clustering algorithm: a study on the distribution of Meissner corpuscles in the skin

A novel hierarchical clustering algorithm was applied to the distribution of Meissner corpuscles in the skin of mammals. This method, called end-to-end linkage (EEL), is useful for grouping data that consists of chain-like contingencies in the multivariable space. Unlike the traditional techniques which uncover hyperspherical clusters (e.g. single linkage), EEL considers the shortest distance between the predefined end pairs of the two clusters as an inter-group distance. This scheme allows characterizing the internal structure of data better than other hierarchical techniques. The anatomical data used in the case study is important for studying the sense of touch. The results show a substantial improvement over the traditional single-linkage method. On average, the number of correctly classified corpuscles is increased to twice the number identified by the single-linkage method. EEL can also be used for analyzing other sensory modalities where geometric relationships need to be explored. In addition, the report contains corpuscle density and epidermal-ridge width data obtained from several species.     

Morphological aspect of the skin terminal corpuscles, previous corrosion with pancreatin.

The capsulated corpuscles of the skin have been studied by pancreatin corrosion methods. With this corrosion, Meissner's corpuscles disappear while those, whose fundamental structure is collagenous, remain intact. We have observed structural differences in these collagenous corpuscles, some being formed as a fine reticulum or with longitudinal or concentric sheaths. Within the corpuscle, there is a totally vascular compartment, the 'vascular hill', which is easily differentiated from the other laminar or reticular segment which is the 'nerve hill'. We conclude that the connective tissue arrangement and the vascular content of the corpuscles contribute to the regulation of the different degrees of sensations perceived by these corpuscles. The tendency that these corpuscles show to unite may be caused because the places, where they are grouped, are the points of greatest sensory perception.     

On the Structure of the Corpuscles of de Quatrefages (Branchiostoma lanceolatum (P))

Corpuscles of de Quatrefages in the rostral connective tissue of amphioxus have been serially sectioned and examined in the electron microscope. It is shown that each corpuscle is composed of one or a few main cells separated and enveloped by sheath cells. From the main cell two cilia protrude into a lumen formed by a bulge in the sheath. The ciliation of the main cell and its axonic continuation into one of the associated nerves suggests that this cell is a primary sensory neurone and the corpuscles of de Quatrefages probably mechanoreceptors.     

PS-100 and NF 70-200 double immunolabeling for human digital skin meissner corpuscle 3D imaging.

For detailed study of complex structures such as corpuscular mechanoreceptors, confocal microscopy can be used with multiple immunolabeling that identifies specifically different subcomponents. In addition, anatomic interpretation is enhanced by three-dimensional reconstruction. Confocal laser micrographs, reconstructed from serial images 1 microm thick of human skin Meissner corpuscles simultaneously immunostained for neurofilaments (NF 70-200) and protein S-100 (PS-100), clearly reveal the complex 3D relationship between Schwann-related lamellar cells immunoreactive for PS-100 and the nerve fibers marked by NF 70-200. The nerve fiber, after branching into the corpuscle, divides into several ramifications, presenting discoidal expansions and flattened fringed sections. The mean nerve diameter was 4 microm +/- 1 (2-5 microm) and the mean size of the discoidal expansions was 15 microm +/- 1 (7-30 microm). Corpuscle size varied from 30-140 +/- 1 microm in length and from 20-60 +/- 1 microm in diameter. This study confirms the presence of neural discoidal areas in Meissner's corpuscles, which are probably involved to some extent with the transduction process. Despite the accuracy of immunolabeling and imaging, an extracorpuscular neural network was never observed in the vicinity of corpuscles, thus giving doubt as to their existence. (J Histochem Cytochem 48:295-302, 2000)     

A Pacinian corpuscle in the human bladder lamina propria

The fortuitous finding of a complex Pacinian corpuscle within the lamina propria of the human urinary bladder is described. It consisted of a complex of encapsulated nerve endings within the areolar connective tissue of the lamina propria immediately adjacent to the inner aspect of the detrusor muscle. It showed no structural evidence of directional sensitivity and was associated on its outer aspect with small unmyelinated axons containing small clear and dense-cored vesicles. This appears to be the first report of an encapsulated nerve ending within the lining of the adult human urinary bladder.     

家鸽Herbst小体对振动的反应特征

鸟类的Herbst小体是一种形态特殊的感觉性神经末梢器官.本文利用电生理学方法,研究了家鸽腿部胫骨-腓骨之间的Herbst小体对振动刺激的反应特征.这种小体对振动刺激非常敏感,当振动频率在600—800赫时,它们有反应的最低阈值约为0.3微米.不同的Herbst小体的反应阈值与频率的关系曲线表明:这种小体具有明显的带通滤波的特征,对振动反应的最佳频率范围为400—1000赫.在适宜频率、超阈值强度的振动刺激下,Herbst小体能以1:1的方式作出反应,即相对于每次正弦波振动刺激都有一个锁相的神经脉冲产生.在背根脊神经节内的细胞外记录表明:对振动敏感的神经节细胞具有和Herbst小体完全相似的反应特征.     

Marfan's Syndrome: The S. Family Re-visited

Marfan''s syndrome has been transmitted by a single pleiotropic autosomal gene through six generations of a Canadian family. At least 42 members of this family have been affected to date. The natural history of this inherited affliction in this family supports the hypothesis that Marfan''s syndrome is an abiotropic disorder of the connective tissues. Premature degeneration of the connective tissues is responsible for the serious ocular and cardiovascular complications of Marfan''s syndrome, for the shortened life span of affected individuals, and indirectly, for the economic distress of affected members of this family. Because no definitive treatment is available for Marfan''s syndrome, an educational approach to the restriction of child-bearing by affected individuals is proposed.     

Cholinergic innervation of the gastric wall of the cat.

The inbuilt intrinsic cholinergic nervous apparatus of the gastric wall of the cat was studied by using two thiocholine methods for mapping the acetylcholinesterase-positive nerves and nerve cells. A rich distribution of acetylcholinesterase-positive nerves was observed in all layers of the gastric wall, except the superficial half of the lamina propria (with the epithelium), which was completely devoid of acetylcholinesterase activity, and the submucosa, in which a scarce distribution of large nerve fascicles and nerve trunks was observed. Acetylcholinesterase-positive ganglia were observed both in the subserous layer and in the myenteric plexus of Auerbach, whereas none were recognized in the submucous plexus of Meissner. This obviously fits well to the results of some electrophysiological experiments which indicate that the submucous plexus of Meissner includes an important intramural pathway from the extrinsic vagus nerves to the antrum region; so the submucous plexus of Meissner seems to be mainly involved in direct rapid conduction of nerve impulses without integrative activities, like a cable. Certain clear differences exist in the pattern of organization of the cholinergic intrinsic nervous apparatus within the different layers of the gastric wall in the fundic and pyloric regions. These differences seem to correspond quite logically to the different types of motor, secretory and neurohumoral activities of these main regions of the stomach. The activity of the non-specific cholinesterases was localized both in the neural elements and the smooth muscle, as well as in some epithelial cells.     

On the fine structure of corpuscles of Stannius of the eel,Anguilla japonica

Summary The Stannius corpuscle of the eel (Anguilla japonica) consists of numerous ovoid or polymorphic lobules separated by loose connective tissue containing blood capillaries. Each lobule is composed of a number of columnar secretory cells, containing numerous secretory granules, and arranged more or less radially. Each secretory granule, spherical, 0.5–1.0 in diameter, and osmiophilic, is surrounded by a limiting membrane derived from the Golgi membrane. The well developed rough-surfaced endoplasmic reticulum is closely associated with the Golgi field. Some Golgi elements might also be intimately associated with the outer nuclear membrane. Numerous glycogen particles are distributed throughout the cytoplasm. The secretory granules which tend to accumulate near the basal part of the cell might be released into the loose connective tissue. From these facts, the corpuscles of Stannius are considered to be protein-secretory endocrine glands without any similarity to the adrenal gland.