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M S Faussone Pellegrini

Publications and source records attributed to M S Faussone Pellegrini.

At least 19 recordsLinked to original sources
PubMed1995

The caecocolonic junction in humans has a sphincteric anatomy and function.

Sphincteric anatomy and function are present at the caecocolonic junction in several mammals. In humans, radiologists and endoscopists have respectively reported a circumferential contraction and a prominent ileocaecal fold at the border area between the caecum and the ascending colon. Anatomical findings on necropsy material failed to confirm its presence. Microscopic studies on surgical specimens showed the existence of muscular and innervational patterns different from those of adjacent areas. The aim of this work was to confirm the existence of a specialised fold at the caecocolonic junction in humans and to ascertain its role by carrying out a study of functional anatomy. Pancolonoscopies were performed on 100 patients and ileocaecal fold behaviour was observed before and after mechanical stimulation. Isolated ileocaecocolonic regions, surgically obtained, were filled with a fixative solution to study their macro and microscopic morphology after stimulation. Endoscopically, the ileocaecal fold was semilunar or circular in shape and spontaneous or evoked spasms occurred in 52 patients. A prominent circular fold could be seen in surgical specimens after stimulation. The entire muscle coat deeply penetrated this fold, showing the features characteristic of the ileocaecal junction. In particular, the inner portion of the circular muscle showed a peculiar arrangement and was thicker than elsewhere. These results show that in humans the caecocolonic junction is provided with a sphincter morphology and function. Little is known about its physiological relevance in ileal flow accommodation and caecal filling and emptying but it should not be underestimated with regard to some colonic motility disorders.

Aged↗
PubMed1988

Fine structure of the receptors at the myotendinous junction of human extraocular muscles.

The myotendinous junction of the human extraocular muscles was studied by electron microscopy. Some peculiar receptorial structures have been found in the majority of the samples examined. These structures are very small and consist of 1) the terminal portion of one muscle fibre, 2) the tendon into which it inserts and 3), within the tendon, a rich nerve arborization, whose branches are always very close to the muscle component. Only one discontinuous layer, made up of flat cells, which lack a basal lamina and often show pinocytotic vesicles, encapsules every musculo-tendinous complex. The tendinous component consists of amorphous ground substance of different electron density, of collagen and elastic fibres and is divided in compartments by ramified cells, which make an inner capsular-like covering to the nerve fibres. Three types of afferent nerve endings can be identified. One type is usually more frequent than the others, possesses a large number of neurotubules and neurofilaments and few mitochondria and is always surrounded by a Schwann cell which forms finger-like processes penetrating into the axoplasm. The second type is only partially enveloped by the Schwann cell. The axoplasm is devoid of neurotubules and contains few neurofilaments, several mitochondria and groups of small clear vesicles placed in the areas uncovered by the glial sheath. The third one is completely surrounded by the Schwann cell, but is devoid of neurotubules and neurofilaments and full of mitochondria. These morphological features correspond well with the probable role of these receptorial structures, which is to ensure very exact and precise ocular movements.

Adult↗
PubMed1985

Ultrastructural peculiarities of the inner portion of the circular layer of the colon. II. Research on the mouse.

A layer of muscle cells consisting of 1-3 rows is present on the inner part of the circular layer of mouse colon. These muscle cells are thinner, with a denser cytoplasm and more caveolae than those of the main portion of the circular layer. A connective interstice divides the two parts of the circular layer and is occupied by a nerve plexus rich in varicosities. Groups of cells, identified as interstitial cells of Cajal, and a nerve plexus rich in varicosities are located on the border between the innermost circular layer and the tela submucosa. The interstitial cells have many cytological features in common with muscle cells (caveolae, basal lamina, thin filaments, smooth endoplasmic reticulum, glycogen particles) and touch each other and the nerve endings frequently and the muscle cells of the innermost layer rarely.

Animals↗
PubMed1984

Morphogenesis of the special circular muscle layer and of the interstitial cells of Cajal related to the plexus muscularis profundus of mouse intestinal muscle coat. An E.M. study.

The morphogenesis of the special layer and the interstitial cells of Cajal (ICC) related to the plexus muscularis profundus (PMP) of mouse intestinal muscle coat has been studied in foetuses at term, neonates not yet fed, suckling animals, weaning animals and adult animals. In foetuses at term, the special layer is absent, but presumed myoblasts of this layer are recognized in the tela submucosa facing the developing circular layer. The ICC, too, are not differentiated and presumed ICC-blasts are tentatively identified in submucosal cells related to nerve fibers. These nerve fibers are considered to belong to the developing PMP. In neonates, the special layer, ICC and PMP are recognizable, but are made up of poorly differentiated elements. In suckling animals, these three structures develop but become almost fully differentiated only at the end of the weaning period, whereas the other components of the muscular coat are already developed.

Animals↗
PubMed1984

Ultrastructural peculiarities of the inner portion of the circular layer of colon. I. Research in the human.

The inner part of the circular layer of the human colon is made up of a special muscle layer, three to eight row thick. Wide areas of connective tissue are found inside this inner circular layer and between it and the outer part of the circular layer. The muscle cells of this innermost layer have several special features: numerous glycogen particles and caveolae, well-developed sarcoplasmic reticulum, and wide contact areas with each other. At the border zone with the tela submucosa, there is a fibrous lamella rich in collagen and elastic fibers, lined by an incomplete layer of circularly orientated fibroblast-like cells. A nerve plexus, rich in varicosities, is located between the two circular layers, and nerve fibers are sparsely located inside the fibrous lamella. Interstitial cells of Cajal were not recognized.

Adult↗
PubMed1983

Some ultrastructural features of the muscular coat of human small intestine.

The muscular coat of human small intestine is constituted by a 'special' layer, by the main component of the circular layer, by the region between the circular and the longitudinal layers and by the longitudinal layer. The 'special' layer is made up of the innermost 4-6 rows of muscle cells of the circular layer and is separated from the main component of the circular layer by a space in which an abundant connective tissue and numerous nerve fibers rich in nerve endings are located. Cells identified as interstitial cells of Cajal are located inside the 'special' layer, the space between it and the main component of the circular layer and in the region between the circular and the longitudinal layers. In this region small bundles of obliquely orientated muscle cells, apparently bridging the circular to the longitudinal layer, are found.

Adult↗
PubMed1982

Some ultrastructural aspects of human pathological pelvi-ureteric junction in idiopathic hydronephrosis.

Five surgical specimens of pelvi-ureteric junction from idiopathic hydronephrotic kidneys were obtained according to the Anderson-Hynes technique and were examined under an electron microscope. Fibrosis and marked alterations of several muscle cells were observed throughout all the specimens. Muscle cell alterations were different form cell to cell, namely: a noticeable development of the rough endoplasmic reticulum and of the Golgi apparatus, a great number of glycogen particles, a wide extension of the smooth endoplasmic reticulum and a disorganization of the filament pattern. The aforementioned alterations could be observed both in 'special' and 'typical' muscle cells; moreover, a reduction in the number and extension of cell-to cell junctions was observed in 'special' muscle cells only. It could be guessed that the modifications observed in the muscle cells and the fibrosis are responsible for the altered motile activity of the upper urinary tract and led to the clinical manifestations of idiopathic hydronephrosis. However, the muscle cell malfunction is probably extended more than in the surgically resected specimens, as in the patients studied it was documented by urodynamic data that the urine flow through the ureter was due to be a wide pelvic-ureteric plasty more than an effective peristaltic contraction of the upper urinary tract.

Adolescent↗
PubMed1981

[Preciseness of the ultrastructural order in the tunic of the small intestine].

The muscular cost of ileum of man was observed both at light and electron microscopes. Four muscular layers could be identified. The first layer appears as an innermost layer of circular muscle. The second layer is the circular one. The third layer occupies the region between circular and longitudinal muscle layers. The fourth layer is the longitudinal one. The structure of both circular and longitudinal layers is like that described for other mammals. The first and the third layers show a very special structure; moreover, interstitial cells of Cajal are found inside the first layer and in the connective tissue lying between the first and second layer. In the third layer two types of smooth muscle cells are present: one types shows a typical structure; the second type, which was never described before, is very peculiar and because of its similarity with interstitial cells of Cajal has been considered of the same nature. Nerve bundles are mainly concentrated between the first and second layers and in the region between circular and longitudinal layers (the third layer), where is localised the myenteric plexus. All these findings are discussed in an attempt to correlate the contractile activities of ileum of man with the structure of its muscular coat.

Humans↗
PubMed1981

[Ultrastructural aspects of the pathology of the pyeloureteral junction].

Are described some observation on the ultrastructure of the muscular coat in three cases of the ureteropelvic junction pathology; the patients were undergone at ureteropelvic resection. The authors underline the presence of an important damage of smooth muscle cells at the ureteropelvic junction, also at the renal pelvis and the upper third of the ureter. The abnormalities of muscle cells are of various type: some of these could be cause of the altered motility and fibrosis of the ureteropelvic junction, constantly observed in such pathological abnormality.

Adult↗
PubMed1981

Ultrastructure of the urinary tract muscle coat in man. Calices, renal pelvis, pelvi-ureteric junction and ureter.

Muscle coat specimens from human calices, renal pelvis, pelvi-ureteric junction, upper, middle and lower ureter segments were examined under an electron microscope. These specimens were taken from 8 patients who had undergone nephroureterectomy: 6 for localized renal carcinoma and 2 for papillary tumor of the pelvis. Two types of smooth muscle cells were observed, "typical" muscle cells and "special" muscle cells. The latter are rich in agranular endoplasmic reticulum, have few myofilaments and are interconnected in numerous, extended, peculiar contact areas. The ratio between these two types of muscle cells differs as also does their innervation between the various segments examined. On the basis of our findings we propose that the "special" muscle cells perform a "pacemaking" function.

Humans↗