Archivio italiano di anatomia e di embriologia. Italian journal of anatomy and embryology最新文献

The authors investigated the morphological changes in the transverse apophysis of C VII by Rx study on an isolated population. Two variations were mainly observed: the transverse mega-apophysis and the cervical rib. The authors found a remarkable incidence of variations, more than the average of the literature. Authors suppose that this results can be attributed at the geographical and economical isolation of the population and they hypothesize a genetic transmission of recessive autosomal type.

The epithelial bell which surrounds the clitoris in most mammals arises by fusion of visceral and parietal layers of the prepuce. Adhesion of the epithelia occurs between the squamous cells and a normal connection is formed by desmosomes and other junctions. There is total absence of cornifications. The squamous epithelial double lamina splits occasionally in some patches where the free surfaces are getting back to a normal process of keratinization as in the wall of the vestibule. In the closed pits the keratin scales form squamous granules without sebaceous secretion. Sometimes a similar process occurs in the human prepuce with the same results as described in cat and rabbit. The granules of keratin are different from the smegmaliths as they do not contain sebaceous secretion.

In the present study a pre-embedding immunoelectron microscopical method ideally suited to detect suspended cell surface-associated antigens, is described. In this method 5nm colloidal gold particles have been enlarged by means of silver enhancement yielding a large marker that is easily detectable at the TEM level. The present method is particularly suited when investigation are performed with a low percentage of labeled cells as well as low antigen expression.

Prenatal development of visual cortex (area 17) was studied in human fetuses of 8-9, 13-15 and 16-18 weeks of gestation, with a view to analyse the early critical events. Under light microscope, five zones of development were seen in all the age groups. The total thickness of cortex of area 17 as well as that of its cortical plate was measured with the help of camera lucida. It was observed that the total thickness of the cortex increased with increase in age. Diversity in the shape, size, staining intensity and arrangement of neurons was noted in the different zones. Most of the cells were found to have a thin rim of cytoplasm and a prominent nucleus with multiple nucleoli. The cells in subventricular zone and cortical plate were regularly arranged in vertical rows while in other zones, they were irregularly scattered. Several mitotic figures were seen in the ventricular zone at 8-9 weeks but later they were also noticed in subventricular and intermediate zones. In the later ages the mitotic figures were observed to be fewer in the ventricular zone. No mitosis was seen in cortical plate at any age period.

A functioning epidermal melanin unit implies a melanocyte capable of transferring melanosomes to keratinocytes; this requires not only melanocytes with adequate dendrites but also "receptive" keratinocytes. Skin with incontinentia pigmenti was examined by electron microscopy. Premelanosomes were occasionally found within keratinocytes and deposits of extracellular granular material that came from vacuolar degeneration of keratinocytes adjacent to melanocytes.

Human frontal cortex neurons of hydrocephalic infants were studied with electron microscope. A number of maturing neurones exhibited shrinkage and increased electron density of cytoplasmic matrix in the midst of gross hydrocephalic interstitial oedema. Remarkable preservation of growth cones and arrays of microtubules in a few neuronal perikarya and axons were discernible. Rows of normal looking neurones with parallel arrays of cisternae of rough endoplasmic reticulum were also detected. Thus, preservation of significant number of neurones was apparent even in cases of extreme hydrocephalus.

The Authors studied the postnatal development of the retinal pigment epithelium in the albino rat, in order to elucidate its morphological and functional evolution, correlated to the numerous functional roles played in Vertebrates (Scheme 1). At birth, epithelial cells show few cytoplasmic organules and the apical surface provided of small depressions. From the third to the fifth postnatal day the first apical microfolds surround the depressions. From the seventh to the ninth day inner segments develop, whilst the apical surface of the epithelial cells is covered by many finger-like microfolds. During the eleventh postnatal day the buds of the outer segments and many lamellar microfolds can be demonstrated. During the sixteenth day the retina reaches its adult morphology. It is therefore well-evident that birth, similarly to many other Vertebrates, is not the last step, but only a moment, in the development of the retina: this process is completed only during postnatal life, when environmental light is able to stimulate every ocular structure.

The structure, the ultrastructure and the number of myonuclei and satellite cells in Duchenne's muscular dystrophy and in control muscles were compared in order to determine the possible changes in the satellite cells population. The bioptical fragments were obtained from 16 healthy (control) and from 16 dystrophic male children from 12 to 96 months of age. The biopsies were embedded in paraffin and in Durcupan and the sections were stained with ematossilin-eosin, P.A.S. for the light microscope observation and with uranil-acetate and lead-citrate for the electron microscope study. Moreover the semithin sections were stained according to the method of Ontell (1974) that is specific for the satellite cells identification. The morphological aspects of the dystrophic muscles are the same previously reported by other authors. The quantitative analysis of the myonuclei and satellite cells in control and dystrophic muscles was carried out on five random sections of each biopsy. The whole number of nuclei (myonuclei and satellite cell nuclei) and the number of the satellite cells nuclei were evaluated and the mean values in controls and dystrophic muscles were compared with the t Student test. The obtained results show that: 1) in the control muscles the satellite cells number is nearly the same in all ages considered; 2) in the dystrophic muscles the satellite cells number is in a statistically significant way greater than in control muscles and show a moderate trend to increase with aging; 3) in the dystrophic muscles the whole number of nuclei (myonuclei and satellite cells) is greater than in control in a statistically significant way and this increase is due to the number of satellite cells.

The results of many investigations on the morphology of the eyes of Vertebrates are proposed, comparing our personal data with the literature available on this argument. It is firstly taken into account the retinal nourishment: it takes place according to direct and indirect mechanisms (Scheme 1). The former (Scheme 2) consist of intraretinal blood vessels and are particularly rare among the Vertebrates; the latter are more numerous and can be classified as constant (choriocapillaris) (Schemes 3A, B), if they are present in all the species up today investigated, or unconstant [Müller cells increased in their number and size (Scheme 5A), papillary cone (Schemes 5B, 8B), membrana vascularis retinae (Schemes 6A, C), falciform process (Schemes 6B, 7A, B, 8B), pecten oculi (Schemes 8A, B)], if they can be demonstrated only in some species, even if belonging to different classes. Their structural and ultrastructural organization, likewise their embryological processes, are examined in detail. The effects of the cyclic changes of light and darkness during a 24 hrs period on the eyeball are then examined; quantitative and qualitative modifications of the mitochondria (Schemes 9A, B) and of the synaptic ribbons (Schemes 10A, B) in the outer plexiform layer, of the photosensitive disks of rods and cones, and of the secretory cells and of the excretory ducts of the Meibomian tarsal glands (Schemes 11A, B, 12A, B) are described. If the animals are exposed to prolonged darkness, no structural changes can be demonstrated; nevertheless, a dark environment can induce the differentiation of peculiar structural specializations, such as the retinal or choroidal tapetum lucidum (Schemes 13, 14, 15). On the contrary, the light, if prolonged or of high intensity, is able to induce irreversible lesions on the photoreceptors and on the pigment epithelium, according to similar mechanisms in all the animals up to now investigated (Scheme 16). In conclusion, it is confirmed the peculiar structural complexity of the eyeball in all the classes of Vertebrates, due to adaptation to the various environmental requests and developed either during the evolutionary processes or during the different steps of the life of a single animal.

Proprioceptive innervation of moufflon extrinsic ocular musculature and m. levator palpebrae superioris was studied. Muscle spindles and Golgi tendon organs were found. The first ones are usually between 1st and 2nd order muscle fascicles. The muscle spindles are highly represented in the extrinsic ocular muscles, but less numerous in m. levator palpebrae superioris. Their number varies according to muscles and individuals. In the same subject, also the ratio between the number of the muscle spindles found in m. rectus dorsalis and that of m. levator palpebrae superioris was examined. Besides, the histological structure of the intrafusal fascicles was investigated. Particular attention was devoted to the nerve supply of the muscle spindle. By means of impregnating methods, sensory and motor endings were identified. Primary and secondary sensory endings only in a few cases showed their usual pattern: motor fibres can end in form of plates or trails. Golgi tendon organs were observed between the tendon and the muscular tissue and are always less numerous.