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At least 19 recordsLinked to original sources
PubMed1975

Postnatal development of the cerebellar cortex in the rat. IV. Spatial organization of bipolar cells, parallel fibers and glial palisades.

The ontogeny of the spatial organization of some components of the molecular layer was investigated in cerebella sectioned systematically in the sagittal, coronal and horizontal planes. There is no discernible organization in the distribution of cells of the proliferative zone of the external germinal layer (EGL) but from birth the differentiating bipolar cells of the subproliferative zone are aligned parallel to the surface and to the long axis of the folium. While they are still in or at the base of the EGL, the bipolar cells emit long processes, the future parallel fibers. The next step is the outgrowth of a vertical process which may reach the base of the molecular layer before the granule cell nucleus becomes translocated. The idea that the cell body truly migrates through the molecular layer is not supported by the observations. Bergmann glia cells are frequently seen in Golgi material in neonates but they are probably less numerous than in older infants and their processes are not as well aligned. It is only gradually that the EGL is perforated by flial endfeet which in older infants are occasionally organized into longitudinal rows. In mature cerebella the parallel fibers are separated by thin and relatively narrow, unstained spaces which are oriented in the longitudinal plane and can be traced from the pial surface to a zone just above the layer of Purkinje cells. It is postulated that these spaces are occupied by glial palisades formed by apposed thin vertical processes to which many Bergmann glia cells contribute. The alignment of these palisades is dependent on the orientation of parallel fibers. When the parallel fibers are reoriented by X-irradiation the glial palisades become correspondingly realigned. These observation indicate that the oriented growth of parallel fibers, which follows the polarization of bipolar cells, determines the spatial organization of the glial framework of the molecular layer. They also suggest that the glial palisades mediate functions that are not primarily developmental in nature.

Animals↗
PubMed1976

Palisaded, encapsulated neuroma of the lip.

A case of palisaded, encapsulated neuroma of the lower lip has been presented. To the best of our knowledge, this is the first reported instance in the dental literature. The lesion characteristically occurs on the skin of the face near the oral, nasal, and orbital mucocutaneous junctions and, therefore, is readily visible to the oral diagnostician. It occurs most often in middle-aged individuals and, although it may clinically mimic other lesions, the operative finding of an easily enucleated mass near a mucocutaneous junction should suggest this lesion in the differential diagnosis. Histologically, the lesion is characterized by three distinct zones--an outer compressed fibrous connective tissue capsule, an inner myxomatous zone, and a central zone of proliferating Schwann's cells arranged in interlacing fascicles with areas of palisaded cells and organoid structures. The lesion is treated by enucleation or excision and has no tendency to recur.

Humans↗
PubMed1978

The Churg-Strauss granuloma: cutaneous, necrotizing, palisading granuloma in vasculitis syndromes.

The cutaneous, necrotizing, palisading granuloma (Churg-Strauss granuloma) was observed on histopathologic study of skin specimens from seven patients. Two patients had Wegener's granulomatosis and one patient each had allergic granulomatosis, limited Wegener's granulomatosis, bacterial endocarditis, systemic lupus erythematosus, and rheumatoid arthritis. The microscopic picture consists of extravascular, palisading, dermal granuloma. The center of the granuloma consists of basophilic fibrillar necrosis in which linear bands of destroyed tissue are interspersed with masses of polymorphonuclear leukocytes and leukocytoclastic debris. This necrotic leukocytic mass is surrounded by histiocytes and some lymphocytes. The clinical lesions are symmetric, erythematous papules or nodules on the extremities. The histopathologic picture of the Churg-Strauss granuloma is unique and, as demonstrated in these cases, indicates the presence of systemic vasculitis.

Granulomatosis with Polyangiitis↗
PubMed1978

Fine structure of the palisade zone of the rat median eminence as revealed by freeze-fracturing.

Nerve terminals in the palisade zone of the rat median eminence were investigated with freeze-fracture electron microscopy. Fracture face P of the specific terminals showed two populations of intramembranous particles (IMP): a large and a small variety. The large IMP-s often formed small irregular clusters. In nerve terminals the total number of both populations of IMP-s was considerably less than that found on P membrane faces of ependymal feet. On fracture face E of the nerve terminals, the number of IMP-s was about a quarter of that seen on fracture face P. On both fracture faces of most terminals a few small round impressions (or elevations respectively) were found which may be interpreted as broken necks of either exo- or endocytotic vesicles. Neither gap nor tight junctions occurred at lateral membranes of the specific axon terminals. Similarly, no membrane specializations were observed with freeze-fracturing on membrane areas adjacent to the basement membrane. The findings are discussed in relation to a possible exocytosis mechanism of the hypothalamic releasing and inhibiting hormones.

Animals↗
PubMed1979

The palisade endings of cat extraocular muscles: a light and electron microscope study.

The palisade endings (PEs), a particular type of nerve ending found only in extraocular muscles of mammals, have been studied using both silver-stained teased preparations and electron microscope techniques. They have been found, in act, in both the proximal and distal muscle insertions of the four recti and the two oblique mucles. PEs are exclusively associated with some of the mitochondria-poor, multiply-innervated muscle fibres present in the globar layer os these muscles, and consist of a multitude of terminal branches embracing the extremity of the muscle fibre and penetrating the infoldings formed by the muscle fibre at its tendinous attachment. The whole formation is surrounded by a thin capsule. These nerve endings present striking similarities to the developing Golgi tendon organ; the terminal branches lying among the collagen fibrils and occasionally making 'sensory-like' close contacts with the muscle fibre are disposed in such a way that they could easily have a sensory role. It was concluded that PEs present sufficient morphological evidence to be considered as sensory, encapsulated, myotendinous receptors, each related to a single multiply-innervated muscle fibre.

Animals↗
PubMed1992

Comparative light-microscopic and immunohistochemical study of traumatic and palisaded encapsulated neuromas of the skin.

The primary hyperplastic nature of palisaded encapsulated neuromas (PENs) has been recently challenged by suggesting a traumatic origin. We studied eight cases of traumatic neuroma (TN) and 12 cases of PEN by routine light-microscopic, histochemical, and immunohistochemical methods to assess evidence of previous tissue injury. Sections from the formalin-fixed, paraffin-embedded tissue were stained with hematoxylin-eosin, trichrome, elastic, reticulin, Giemsa, colloidal iron (with and without hyaluronidase), and Bielschowsky silver stains. Antibodies were applied to collagen types I, III, and IV, MAC 387, factor XIIIa, alpha 1-antitrypsin (A1AT), epithelial membrane antigen (EMA), Leu-7, and myelin basic protein using ABC techniques. We found that (a) in TN the individual fascicles were usually surrounded by perineurial cells, whereas in PEN the perineurial cells were observed mainly in the capsular areas and only rarely within the fascicles as evidenced by EMA antibodies; (b) histochemically TN contained considerably larger amounts of collagen (types I and III), acidic mucin, and myelin products than did PEN; and (c) neither PEN nor TN contained increased inflammatory cells or cells positive for factor XIIIa, MAC 387, or A1AT. We conclude that (a) there are substantial structural and histochemical differences between TN and PEN, (b) the changes suggest that the classic form of PEN has a different histogenesis than TN, and (c) on histologic grounds, chronic minor trauma could not be excluded as an etiologic factor for PEN.

Antigens, Differentiation↗
PubMed1977

Solitary renal plasmacytoma with palisading tumor vascularity.

A solitary extramedullary plasmacytoma of the kidney associated with contralateral myeloma kidney is reported. The tumor demonstrated extensive palisading tumor vessels, heretofore thought to be characteristic of renal lymphoma. Plasmacytoma as the etiology of a renal mass should be considered when there is nonfunction of a normal-appearing contralateral kidney.

Adenocarcinoma↗
PubMed1975

Influence of castration on incorporation of exogenous peroxidase into "synaptic" vesicles of the median eminence. II. The perivascular part of the palisade zone in male rats.

In the median eminence of male rats, nerve profiles in the immediate vicinity of portal capillaries have been divided into 4 categories on the basis of their vesicular content: profiles a with agranular "synaptic" vesicles of about 50 nm, b with similar agranular vesicles and also with granular vesicles of mainly 60-140 nm, c with granular vesicles alone and d without vesicles. Twenty-four hours after castration, the percentage of profiles of category a was significantly increased when compared with sham-operated animals, whereas the percentage of profiles of category b was significantly decreased. After intravenous injection of exogenous peroxidase, especially the nerve profiles located in direct contact with the outer basement membrane of the portal capillaries contained peroxidase positive "synaptic" vesicles. Injection off peroxidase after castration resulted in a significant increase in the percentage of nerve profiles containing both peroxidase positive and peroxidase negative "synaptic" vesicles (category a). It is suggested that, in certain nerve terminals, castration may lead to release off the content of granular vesicles, which may contain gonadotropin releasing factor. This release then may cause that nerve terminals with agranular vesicles and granular vesicles (category b) change in their vesicular content and are therefore classified as terminals with only agranular vesicles (category a). An increased turnover rate in the ultrastructurally affected terminals may be reflected in increased uptake of exogenous peroxidase. The observations imply that certain neurones projecting to portal capillaries in the median eminence are, directly or indirectly, sensitive to changes in the level of gonadal steroids.

Animals↗
PubMed1976

Microfluorimetric quantitation of catecholamine fluorescence in rat median eminence. I. Aspects on the distribution of dopamine and noradrenaline nerve terminals.

Using the fluorescence histochemical technique of Falck and Hillarp, a quantitative microfluorimetric study of the catecholamine fluorescence in the median eminence has been performed. On the basis of morphologic criteria, the median eminence was subdivided into various areas from which the microfluorimetric measurements were made; the subependymal layer, the medial and lateral palisade zone of the rostral and the central and caudal region of the median eminence (for definitions of the various areas and regions, see Anatomical Subdivision). The highest fluorescence intensities were recorded from the lateral palisade zone, indicating that this area has the most dense catecholamine innervation, whereas the lowest fluorescence intensities were recorded from the subependymal layer. Dopamine-beta-hydroxylase inhibition produced by FLA-63, fusaric acid or diethyldithiocarbamate resulted in all cases in a 50-70% reduction of the catecholamine fluorescence in the subependymal layer, whereas only minute effects were observed in the lateral palisade zone. In the medial palisade zone, these treatments generally led to a substantial reduction (30-50%) of the catecholamine fluorescence. Basal hypothalamic deafferentation according to Halasz, or lesioning of the ventral catecholamine bundle, produced an almost complete disappearance of the fluorescence in the subependymal layer, while both procedures were largely ineffective in affecting the catecholamine fluorescence in the lateral palisade zone. On basal hypothalamic deafferentation the catecholamine fluorescence in the medial palisade zone was markedly reduced (40-60%), while the ventral bundle lesions were less efficient in this respect. From the present results it is suggested that the subependymal layer is mainly innervated by noradrenaline nerve terminals and the lateral palisade zone is mainly innervated by dopamine nerve terminals, whereas the medial palisade zone receives a mixed innervation of dopamine and noradrenaline terminals, the dopamine proportion being in the order of 50-75% of total catecholamine content.

Animals↗
PubMed1978

[Histology of cerebellar metastasis of bronchial oat cell carcinoma].

Anatomo-pathological examination of 28 bronchic oat-cell carcinoma, all with cerebellar metastases and which are very often cerebral. In half of the cases, these localized cerebellar metastases contain palisades. These formations which haven't been described until now within intracranial metastases, can't be considered as artefacts as their frequency approaches 50% of the cases. Neither the primitive tumor nor the extracerebral metastases of the series reveal palisades; sometimes some of them exist in their cerebral metastases. As far as the epidemiology, the clinical evolution, the survival time and the extracerebral localization are concerned, these 28 cases are not different from those described in medical literature. The morphological, hormonal and biochemical knowledge we possess about this type of cancer tends to prove its neuroectodermic origin as well as its close relation with both the APUD- and the "endocrinien diffus" systems. The described palisading elements represent another very specific morphological point which tends to support this theory: they appear principally in the tumors of the central and peripheral nervous system. Although the author is not able to explain the reason of palisades' genesis in cerebellar metastases, he insists on the fact that it iw very important - as far as every days' biopsy's study is concerned - to proceed to a differential histological diagnosis in regards to certain primitive tumors of the nervous system (among these the medulloblastoma) and a cerebellar metastasis of this type of bronchic carcinoma.

Aged↗
PubMed1979

[The ultrastructure of the endings of nerve fibers of ordinary hairs of mammals under normal conditions and during degeneration and regeneration].

At ultrastructural level, three zones are distinguished of the palisade endings of nerve fibers, most of them in contact with the basement membrane of the outer epithelial sheath of the radix pili on rat muzzle. After division of the supplying nerve (n. infraorbitalis) in test animals of the same species, its nerve fibers and palisade endings undergo degeneration, followed by regeneration within 4-5 months. Changes in the ultrastructure of the mentioned nerve elements are thoroughly studied and demonstrated in the course of the two processes. While within 6...12 days of the operation, the palisade endings degenerate, 130 days after the intervention most of them are restored and exhibit an appreciable difference relative to their typical ultrastructure in normal state. The Schwann's cells processes, enveloping degenerated and regenerated palisade endings, similarly display marked fine-structure alterations.

Animals↗
PubMed1977

Comparison of vegetative anatomy of Piperales. II. Leaf.

Many characters of leaf (hair, hypodermal cells, palisade layers, intercellular space, distinction between spongy and palisade parenchyma, "palisade ratio", distribution of collenchyma and sclerenchyma, presence or absence of starch grains, calcium oxalate crystals, number, shape and arrangement of bundles of petiole) are useful distinguishing characters. Reduction of palisade layers seems to be the trend of evolution in Piper and Peperomia.

Plants↗
PubMed1979

Quantitative radioautographic light and electron microscopic analysis of the localization of monoamines in the median eminence of the rat. I. Catecholamines.

By means of light and electron microscopic radioautography a quantitative study of the regional distribution of catecholamines in the median eminence of the rat was carried out. One hour after intraventricular injection of 3H-dopamine the highest radioautographic reaction was recorded in the external zone, especially in the lateral palisade zone where many neurosecretory terminals are separated from the basal lamina of the portal pericapillary space by a glial "cuff". This area showed the highest percentage (52%) of labelled catecholamine containing neurosecretory terminals as well as the maximal silver grain density per one terminal. In the medial palisade zone where direct neurovascular contacts with the capillary loops prevail, only 27 per cent of neurosecretory terminals were found to harbour tritiated dopamine. On the average 35 per cent of neurosecretory terminals in the median eminence of the rat contain catecholamines (both dopamine and noradrenaline). Pretreatment of animals with recretory terminals as well as grain density over terminals were decreased in both the medial and lateral palisade zones, although to a lesser degree in the latter. The site of origin of catecholamine fibers as well as the mode of catecholamine action at the level of the median eminence are discussed.

Animals↗
PubMed1979

Quantative radioautographic light and electron microscopic analysis of the localization of monoamines in the median eminence of the rat.

Serotonin containing structures in the median eminence of the rat have been studied by quantitative light and electron microscopic radioautography following intraventricular infusion of tritiated 5-hydroxytryptophan. One hour after injection of the tracer the highest density of silver grains was recorded in the ependymal and external zones, especially in the lateral palisade zone. The proportion of labelled neurosecretory terminals was also larger in the lateral palisade zone (29%) as compared with the medial palisade zone (13%), although the mean number of developed silver grains per one terminal was higher in the latter. On the average, 16% of neurosecretory terminals sequestered radiolabelled 5-hydroxytryptophan in the external zone of the rat median eminence. It is suggested that serotonin, like catecholamines, is discharged from neurosecretory terminals localized in the external zone and via the portal circulation affects the function of the anterior pituitary. The sites of origin of serotoninergic structures of the median eminence as well as the possible role of monoamine (catecholamine and indolamine) neurohormones in a dual peptidergic and monoaminergic control of anterior pituitary functions are discussed.

Animals↗
PubMed1975

[Light and electron microscope studies on cysts of Sarcocystis ovicanis Heydorn et al. (1975) within muscle fibres of sheep (author's transl)].

Four conventionally reared lambs, isolated at the age of 5 and 8 weeks, were orally infected with oocysts and sporocysts from dogs, which had been fed raw muscles from sheep containing small cysts of S. tenella. Three lambs, each infected with 100,000 sporocysts, were killed at days 41, 63 and 81 p.i. The other lamb was used for a non-infected control. The development of Sarcocystis-cysts in muscle cells of the infected lambs was studied by light and electron microscopy. The cyst was always situated within a muscle fiber which was never surrounded by fibrillar layers (=no secondary cyst wall). The cyst was limited by a unit membrane, which was thickened at numerous places of the interior by osmiophilic material. This complex is called primary cyst wall (= Primärhülle), reaching a thickness of up to 25 nm. In old cysts this primary wall was regulary folded, forming palisade-like protrusions of about 3.5 mu in length. In light microscopy the combined protrusions had the appearance of a radially striated "thick wall", because of their close proximity to each other. During formation of the palisade-like protrusions the thin areas of the primary wall were restricted to the base of the protrusions and to the small space between the protrusions. Here, the single unit membrane formed vesicle-like invaginations of about 40 nm in diameter into the interior of the cyst. Vesicles seen in the cysts were thought to derive from these invaginations. Within the palisade-like protrusions never fibrillar or tubular elements appeared. In comparing the fine structure of the cyst wall of the small cysts, studied here, with the macroscopically visible cysts we found significant differences. These differences in the morphology confirm the results of transmission experiments, by which it was shown that S. tenella as described in literature is part of at least two coccidian life cycles. So the term S. tenella was replaced by two new species: S. ovicanis (final host: dog) and S. ovifelis (final host: cat) Heydorn et al. (1975).

Animals↗