The innervation of human muscularis mucosae: an ultrastructural study

The muscularis mucosae, a thin band of smooth muscle located at the base of the gastrointestinal mucosa, has been the topic of very few studies .The muscularis mucosae might regulate the absorptive and secretory functions of the gut through movements of the mucosal surface (1).The autonomic innervation of this tissue is almost completely unknown.Therefore we have carried out an ultrastructural study on nerve fibers of muscolaris mucosae by using archived mucosal rectal biopsies of children of different age , examined in the past for the diagnosis of neurometabolic disease and resulted negative. Nerve fibers of muscularis mucosae were unmyelinated. They contain several axons with the characteristics of intervaricose tract completely or almost surrounded by Schwann cells . Other axons in the nerve fibers appear as varicosities partly covered with Schwann cell cytoplasm or naked, and filled with vesicles and mitochondria .The vesicles in the same varicosity appear pleomorphic: small clear-core vesicles , dense -core of small diameter or less often dense-core of larger type. The membrane of muscle cells often protruded toward the varicosity . No synaptic specialization was observed.With very low frequency we found varicosities in intimate contact with the plasmalemma . Pleomorphic vesicles inside the same varicosity suggest a complex neurotransmission based on the release of classical transmitter and cotransmitters.The physiological relevance of these nerves remains unclear. Strips of longitudinal muscularis mucosae isolated from the human, guinea pig and rat colon responded with concentration-dependent contractions to the application of several spasmogens (1). In the human muscularis mucosae, neurokinin A was most potent, followed by carbachol, prostaglandin F2 and acetylcholine. These findings suggest the possibility that the muscularis mucosae is innervated by excitatory cholinergic nerves (1).On the other hand in oesophagus exogenously applied adrenaline inhibited spontaneous activities of the muscularis mucosae motor activity. Adrenergic nerves might inhibit spontaneous motility via the inhibition of cholinergic neurotransmission. VIP- , NPY-, CGRP- and galanin-immunoreactive nerve fibers were observed in the human esophageal muscularis mucosae but their function remains unknown (2)

Sternal foramina : anatomy and clinical significance

Vengono presentati casi di forami sternali multipli e viene discussa l'importanza della conoscenza da parte dei clinici di questa anomalia

Osteologic topography of the trochlear spine and fovea as landmarks to locate the superior oblique trochlea

The position of the superior oblique tendon, attached to the orbital roof by a cartilaginous trochlea, is marked by osteologic landmarks like the trochlear spine and/or fovea, approximately located at the superomedial angle of the orbit. Aim of the study is to place the trochlea within the orbit with a series of measurements to give the surgeon detailed references of the trochlea location. For this purpose, we undertook the study of a collection of dry skulls of known sex and age to investigate bony landmarks. Measurements were taken to assess the position of the trochlear spine/fovea on a frontal plane employing a system of vertical and horizontal lines passing through known bony reference points. Measurements were also recorded between the trochlear spine/fovea and the orbital opening on one side and the anterior rim of the optic canal on the other side. The distances of the trochlear spine/fovea from the lines passing along the supraorbital notch and the frontozygomatic suture were respectively 8.5 ± 2.3 mm and 5.7 ± 1.5 mm. The distances of the trochlear fovea/spine from the anterior orbital opening and from the anterior rim of the optic foramen were respectively 4.2 ± 0.11 and 37.5 ± 3.1 mm. Only the distance from the optic canal showed sex-related differences. In conclusion, to avoid unwanted injuries of the trochlea of the superior oblique in surgery of the superomedial angle of the orbit, the surgeon should be aware of its precise position

HISTOPATHOLOGICAL FINDINGS IN SYSTEMIC SCLEROSIS-RELATED MYOPATHY: FIBROSIS AND MICROANGIOPATHY

Objectives: The objective of this study was to identify specific histopathological features of skeletal muscle involvement in systemic sclerosis (SSc) patients. Methods: A total of 35 out of 112 SSc-patients (32%, including 81% female and 68% diffuse scleroderma) presenting clinical, biological and electromyographic (EMG) features of muscle weakness, were included. Patients underwent vastus lateralis biopsy, assessed for individual pathologic features including fibrosis [type I collagen (Coll-I), transforming growth factor β (TGF-β)], microangiopathy [cluster of differentiation 31 (CD31), pro-angiogenic vascular endothelial growth factor A (VEGF-A), anti-angiogenic VEGF-A165b], immune/ inflammatory response [CD4, CD8, CD20, human leucocyte antigens ABC (HLA-ABC)], and membranolytic attack complex (MAC). SSc biopsies were compared with biopsies of (n = 35) idiopathic inflammatory myopathies (IIMs) and to (n = 35) noninflammatory myopathies (NIMs). Ultrastructural abnormalities of SSc myopathy were also analyzed by transmission electron microscopy (TEM). Results: Fibrosis in SSc myopathy (81%) is higher compared with IIM (32%, p < 0.05) and with NIM (18%, p < 0.05). Vascular involvement is dominant in SSc muscle (92%), and in IIM (78%) compared with NIM (21%, p < 0.05). In particular, CD31 shows loss of endomysial vessels in SSc myopathy compared with IIM (p < 0.05) and with NIM (p < 0.01). VEGF-A is downregulated in SSc myopathy compared with IIM (p < 0.05) and NIM (p < 0.05). Conversely, VEGF-A165b is upregulated in SSc myopathy. The SSc immune/inflammatory response suggested humoral process with majority (85%) HLA-ABC fibral neoexpression and complement deposits on endomysial capillaries MAC, compared with IIM (p < 0.05), characterized by CD4+/CD8+/B-cell infiltrate, and NIM (p < 0.05). TEM analysis showed SSc vascular alterations consisting of thickening and lamination of basement membrane and endothelial cell ‘swelling’ coupled to endomysial/perimysial fibrosis. Conclusions: Fibrosis, microangiopathy and humoral immunity are predominant in SSc myopathy, even if it is difficult to identify specific histopathological hallmarks of muscle involvement in SSc, since they could be present also in other (IIM/NIM) myopathies. © 2016, © The Author(s), 2016

Immunohistochemical detection of myosin heavy chain isoforms in human cremaster muscle

Cremaster muscle (CM) forms a thin network of fascicles, around the spermatic cord and testis, connected by loose areolar tissue forming the cremasteric fascia. CM has a non somitic embryologic origin, as it derives from mesenchymal differentiation of the gubernacular tip (1).Thus it is not to be considered a passive extension of internal oblique muscle. CM is composed both of striated and smooth muscle cells; it is innervated by genitofemoral nerve (2). Its striated fibres, in contrast with skeletal muscles, present with a multifocal innervation by multiple neuromuscular synapses (3). Myosin isoforms are the major determinant of the contractile and biochemical heterogeneity of skeletal muscle fibers. Non somitic muscles, such as extrinsic ocular muscles, show a distinct pattern of myosin heavy chains distribution. The aim of our study was to characterize the expression of myosin isoforms in CM fascicles; biopsy samples were obtained from cases of cryptorchidism, retractile testis and inguinal hernia, undergoing surgery. Immunohistochemistry confirmed the previously identified type 1 predominance (1) and showed a high occurrence of hybrid fibres, coexpressing two or more myosin isoforms. In contrast with age-matched limb muscles, persistence of developmental/neonatal myosin heavy chains was detected, beyond the determined timecourse of physiological shifting from immature isoforms (4). On the basis of shared peculiar embryological derivation, expression of superfast extraocular myosin MyH13 was also investigated on CM specimens, showing sarcoplasmic reactivity, undetectable in limb muscles. The high share of hybrid fibres, the persistence of immature myosin and MyH13/MyHCslow coexpression are peculiar features, suggesting a functional/biochemical individuality of CM, related with multiple innervation and distinct embryological development

The anatomical world of Paolo Mascagni. Reasoned reading of the anatomy works of his library

Paolo Mascagni was a man with deep interests in various fields of knowledge. This explains the richness and diversity of his library, where alongside the volumes that treat of Medicine issues there are books of Physics, Chemistry, Natural Sciences, but also of Agriculture and Hydrology, without neglecting the Humanities. It is obvious, however, the strong preponderance of Anatomy volumes, subject of this paper. Mascagni was well aware of how necessary it was for an anatomist of that time to possess the textbooks of ‘greats’ that had traced the history of Anatomy until the eighteenth century. He bases his knowledge on the works of his predecessors to fundamentally innovate the methodology of Anatomy studies: an innovation that can be observed in his writings and in his approach of anatomical science analysis. © Mattioli 1885

Geometric complexity identifies platelet activation in familial hypercholesterolemic patients

Familial hypercholesterolemia (FH), a genetic disease, is associated with a severe incidence of athero-thrombotic events, related, also, to platelet hyperreactivity. A plethora of methods have been proposed to identify those activated circulating platelets, none of these has proved really effective. We need efficient methods to identify the circulating platelet status in order to follow the patients after therapeutic procedures. We propose the use of computerized fractal analysis for an objective characterization of the complexity of circulating platelet shapes observed by means of transmission electron microscopy in order to characterize the in vivo hyperactivated platelets of familial hypercholesterolemic patients, distinguishing them from the in vivo resting platelets of healthy individuals. Platelet boundaries were extracted by means of automatically image analysis. Geometric complexity (fractal dimension, D) by box counting was automatically calculated. The platelet boundary observed by electron microscopy is fractal, the shape of the circulating platelets is more complex in FH (n = 6) than healthy subjects (n = 5, P < 0.01), with 100% correct classification in selected individuals. In vitro activated platelets from healthy subjects show an analogous increase of D. The observed high D in the platelet boundary in FH originates from the in vivo platelet activation. Computerized fractal analysis of platelet shape observed by transmission electron microscopy can provide accurate, quantitative data to study platelet activation in familial hypercholesterolemia and after administration of drugs or other therapeutic procedures. © 2015 Wiley Periodicals, Inc