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G Germanà

Publications and source records attributed to G Germanà.

At least 37 records · Page 2Linked to original sources
PubMed1997

The three-dimensional architecture of the myosalpinx in the cow as revealed by scanning electron microscopy.

The three-dimensional architecture of the myosalpinx in the cow has been investigated by means of scanning electron microscopy after removal of interstitial connective tissue with NaOH digestion. In the extramural portion of the tubo-uterine junction, in the isthmus and ampulla, the myosalpinx is made up of oblique bundles of variable orientation and length, which are loosely distributed in the tubo-uterine junction and densely packed in both isthmus and ampulla. These bundles intersect and merge into the surrounding musculature. Our observations demonstrate how myosalpinx consists mainly of bundles of muscular fibers independent one of another, which show a multiple spatial arrangement and form a complex network. Such a muscular architecture is likely more suitable for stirring rather than pushing the embryos and gametes through the tube.

Animals↗
PubMed1996

Age-related changes in the medullary reticular epithelial cells of the pigeon bursa of Fabricius.

BACKGROUND: The medulla of the avian bursal lymphoid follicles contains heterogeneous cell populations, including the so-called medullary reticular epithelial cells (REC). These cells may contribute to the bursal microenvironment for B-lymphocyte differentiation and maturation. The bursa of Fabricius undergoes well-characterized posthatching developmental changes, but the age-related changes of the medullary REC have not been studied. The present study approaches this topic by analyzing hallmarks of epithelial cells: the occurrence of cytokeratin-type intermediate filaments and of desmosomes and desmoplakins in pigeon medullary REC. METHODS: The bursae of Fabricius of male king pigeons (Columba livia L.) Morini's strain were examined at different ages (from hatching to 120 days after hatching) by light microscopic immunohistochemistry for pan-cytokeratins and desmoplakins and by transmission electron microscopy. The area occupied by medullary cytokeratin-immunoreactive cells was evaluated with quantitative image analysis. RESULTS: At hatching, cytokeratin immunoreactivity was not detected in the bursal lymphoid follicles. During the posthatching growth period of the organ (7-75 days), there was a progressive and significant increase in the area occupied by cytokeratin-immunoreactive medullary REC, in the intermediate filaments filling the cytoplasm of REC, and in the number of desmosomes. Conversely, during the regressive period analyzed (90-120 days), the density of cytokeratin-positive cells progressively decreased, although they retained their ultrastructural characteristics. The evaluation of desmoplakin immunoreactivity paralleled that of cytokeratin. CONCLUSION: The present results demonstrate that the medullary REC of the pigeon bursa of Fabricius undergoes age-dependent changes parallel with that involving the whole organ. The possible contribution of medullary REC to the bursal microenvironment is discussed.

Aging↗
PubMed1996

Muscarinic cholinergic receptor subtypes in the pigeon bursa of Fabricius: a radioligand binding and autoradiographic study.

The pharmacological profile and the anatomical localisation of muscarinic cholinergic receptor subtypes were studied in the pigeon bursa of Fabricius, using radioligand binding and autoradiographic techniques with [3H]quinuclidinyl benzilate (QNB) as a ligand. [3H]QNB was specifically bound to sections of bursa of Fabricius. The binding was time-, temperature- and concentration-dependent. The dissociation constant was 0.31 +/- 0.02 nM, and the maximum density of binding sites averaged 38 +/- 2.5 fmol/mg protein. The pharmacological profile of [3H]QNB binding to sections of pigeon bursa of Fabricius was consistent with the labelling of M2, M3 and M4 muscarinic receptor subtypes. Light microscope autoradiography showed the localisation of [3H]QNB binding sites in the medulla, in follicular septa, in the cortico-medullary border and in lesser amounts in the cortical layer. The functional significance of these receptors should be clarified in future studies.

Animals↗
PubMed1996

Localization of Trk neurotrophin receptor-like proteins in avian primary lymphoid organs (thymus and bursa of Fabricius).

The avian thymus and bursa of Fabricius are the specific organs where the maturation and differentiation of T- and B-lymphocytes, respectively, take place. In the mammalian lymphoid organs mRNAs of the neurotrophins and their receptors have been identified but their localization at the protein level remains still unknown. This study was undertaken to analyze the localization of the Trk family of tyrosine kinase receptors in the avian primary lymphoid organs (thymus and bursa of Fabricius) during the posthatching development using immunohistochemistry. These proteins serve as essential constituents of the high affinity receptors for neurotrophins. In the thymus of all groups of age specific immunoreactivity (IR) was observed for all three Trks: TrkA-like IR was found labelling medullary epithelial cells and a subpopulation of cortical epithelial cells; TrkB-like IR was found in the medullar dendritic cells and cortical macrophages; TrkC-like IR labelled the cortical epithelial cells and scattered medullar clusters of epithelial cells (including Hassal's corpuscles). Quantitative analysis revealed age-dependent decrease in the area occupied by TrkA-like IR in the cortex, and age-dependent increase in the medulla; no changes were detected in the area occupied by TrkB-like IR; the TrkC-like immunoreactive cells increase from 7 to 30 days and then decrease. Regarding to the bursa of Fabricius, TrkA-and TrkC-like IR were exclusively found in the epithelial cells of the follicle associated and the interfollicular epithelia, as well as TrkC-like IR in some medullary reticular epithelial cells of adult animals. Nevertheless, TrkB-like IR labelled extrafollicular unidentified cells in 7 days old animals, and the follicular secretory dendritic cells at 30 and 60 post-hatching. The area occupied by the medullary TrkB-like IR cells increased between 30 and 60 days. No immunostaining of lymphocytes was observed for any of the assessed antigens. The blood vessels of both the thymus and the bursa of Fabricius were immunoreactive for TrkA- and TrkC-like proteins. The present results provide evidence for the localization of Trks in the non-lymphoid cells (epithelial and dendritic) of the avian primary lymphoid organs, suggesting a role for neurotrophins in these cells. Moreover, the selective cell localization of each Trk protein, and the absence of apparent overlapping, claims for a differential role of the specific Trk ligands. Whether or not these findings have functional relevance for T- and B-lymphocytes processing in avian primary lymphoid organs is discussed.

Age Factors↗
PubMed1996

The three-dimensional architecture of the myosalpinx in the sheep as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of the myosalpinx in the sheep was studied by scanning electron microscopy after the removal of interstitial connective tissue with NaOH digestion. In the extramural portion of the tubo-uterine junction, the myosalpinx is made up of densely packed, circularly arranged superficial fibers and of innermost loose fiber bundles following an almost longitudinal course. In the isthmus and ampulla, the myosalpinx is constituted by oblique bundles of variable length, which run around the tube and merge into the surrounding musculature, giving rise to a plexiform arrangement. The present 3-D observations demonstrate that the sheep myosalpinx consists mainly of single muscular fibers and more complex bundles which show a multiple spatial arrangement and a plexiform distribution. Such a muscular architecture is more likely suited for stirring rather than pushing the embryos and gametes through the tube.

Animals↗
PubMed1996

The three-dimensional architecture of the myosalpinx in the rat (Rattus norvegicus) as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of myosalpinx in the rat has been investigated by means of scanning electron microscopy after microdissection and removing interstitial connective tissue with 6N NaOH digestion. In the extramural portion of tube-uterine junction the myosalpinx shows circularly arranged fibers originating from the uterus, together with oblique fibers typical for the salpinx, which occur more frequently in the deeper layers. As fibers approach the mucous folds they assume a plexiform arrangement, which is maintained through all tubal segments. In the isthmus surface fibers form wide muscle rings around the elbow of loops, peculiar to the rat tubal morphology. Surface fibers in the ampulla and pre-ampulla have an even circular course. Our 3-D results reveal that the muscular architecture of rat tube is mainly organized in concentric, monolayered shells with a plexiform arrangement tightly fastened together. Functionally, this muscular arrangement seems to be capable of stirring rather than pushing the embryo and gametes. Finally, such a plexiform network might work as a mechanism of "tube locking" in proximity of isthmic loops as well as at the level of the ampullary-isthmic junction.

Animals↗
PubMed1995

Age-related changes of the noradrenergic and acetylcholinesterase reactive nerve fibres innervating the pigeon bursa of Fabricius.

Age-dependent changes in the innervation of the pigeon (Columba livia, L.) bursa of Fabricius, from hatching to 120 days of age, were studied by fluorescence-histochemical and neurochemical methods for demonstrating noradrenergic and acetylcholinesterase (AChE)-reactive nerve fibres respectively. The distribution of both nerve fibre types was largely perivascular. Furthermore, a few isolated nerve fiber profiles were observed beneath the bursal epithelium, in the interfollicular septa and in the follicular cortex. No nerve fibre profiles reaching the medulla of the lymphoid follicles were observed. In addition to nerve fibres, AChE reactive neuron-like cells were encountered within the capsule and interfollicular septa. AChE reactivity was also found in dendritic-like cells localized in the cortical and cortico-medullary border. No changes in the density of perivascular noradrenergic innervation were noticeable during the ages studied, whereas the density of AChE-reactive fibres supplying vessels reached the adult pattern at 30 days, and then remained unvaried. The density of non-perivascular nerve fiber profiles, specially the AChE reactive type, increased until 30 days, remained unchanged until 75 days and then increased with aging (90-120 days). The interrelationship between the autonomic nervous system and the immune system is discussed.

Acetylcholinesterase↗
PubMed1995

Immunohistochemical localization of neurotrophin receptor proteins in human skin.

The target organs of neurotrophin-dependent sympathetic and sensory neurons, including the skin, synthesize and release neurotrophins, primarily NGF. Neurotrophins undergo retrograde axonal transport, and exert specific function in the perikarya of the responsive neurons. Moreover, evidence exists for an autocrine and/or paracrine function of neurotrophins in the skin. This study analyses the immunohistochemical localization of low (gp75) and high-affinity (gp140 trkA, gp145trkB and gp145trkC) neurotrophin receptor proteins in the human glabrous skin. We consider that the expression of neurotrophin receptors may be indicative of neurotrophin activity. Specific gp75 and gp140trkA-like immunoreactivity (IR) were observed highly co-localized in (1) epidermis, primarily in the basal keratinocytes; 2) sweat glands; (3) blood vessel walls, mainly in the muscular layer; (4) Schwann and perineurial cells of nerve trunks; (5) periaxonic cells forming sensory nerve formations (Meissner's and Pacini's corpuscles); (6) large axons of nerve bundles and of sensory corpuscles; gp145trkB-like and gp145trkC-like were found labelling nerve fibers and sensory nerve formations, as well as blood vessels and sweat glands, but not epidermic cells. The results suggest that, in addition to the well known neurotrophic functions, neurotrophins may also regulate unknown functions in non-nervous cutaneous cells, which are targets for neurotrophin-dependent sympathetic and sensory neurons.

Humans↗
PubMed1995

Experimental incomplete spinal cord injury: treatment with a combination of nimodipine and adrenaline.

The effect of combination of nimodopine and adrenaline treatment on the motility deficits following secondary spinal cord damage was studied. Morphometric axonal analyses were also done. Incomplete spinal compression was induced in albino New Zealand rabbits anesthetized with ketamine. Neurological deficit was assessed by Tarlov's scale. The animals were divided into different groups. In one group the animals were anesthetized and subjected to all procedures except spinal cord injury and pharmacological treatment. Each of the other groups were divided into 2 subgroups; the spinal cord compression was induced for 2 min in one subgroup and 5 min in other subgroup. The pharmacological treatment in different groups consisted of slow intravenous infusions of saline alone, combination of adrenaline and nimodipine, nimodipine alone and adrenaline alone. The evolution of the motor damage was evaluated by comparing scores obtained with Tarlov's scale 1, 24 and 48 hrs after the end of spinal cord compression. In all animals, spinal cord compression for 2 and 5 min induced a 5th degree motor deficit. Treatment with saline improved slightly the motor deficit. The improvement of motor deficit was much better when a combination of nimodipine and adrenaline was used. The animals treated with nimodipine alone showed a better recovery in comparison with the animals treated with saline alone.

Animals↗
PubMed1994

Age-related changes in the secretory-dendritic cells of the pigeon bursa of Fabricius: an immunohistochemical and ultrastructural study.

The present study was undertaken to determine, by means of immunohistochemical techniques, image analysis and ultrastructural methods, whether the secretory-dendritic cells (SDC) of the pigeon bursa of Fabricius undergo changes from hatching to the involutive stage (120 days) of the organ. A monoclonal antibody against vimentin (VIM) was used to label SDC. VIM-like immunoreactivity (VIM-L IR) was observed labelling dendritic cell profiles in all age groups. These cells are primarily localized within the medulla and at the cortico-medullary border of the lymphoid follicles. At hatching VIM-L IR was present mainly in the cell bodies, whereas during post-hatching bursal growth (7 to 75 days) it was also present in the cell processes. Conversely, the involutive period examined (90-120 days) was characterized by a progressive decrease of VIM-L IR in the SDC processes. Quantitative studies confirmed the immunohistochemical findings. At the ultrastructural level, there was a progressive increase from 0 to 90 days of age in both the number and size of secretory granules and break-down bodies, as well as in the length of the SDC processes. The involutive stage showed the reverse phenomena. The present results demonstrate that the SDC of the pigeon bursa of Fabricius undergo age-related changes parallel with that of the organ. The possible involvement of SDC in the maintenance of the bursal microenvironment and their role in the maturation of lymphoid line cells is discussed.

Aging↗
PubMed1993

Circadian rhythm of glucose utilization in the pineal body of rats of different ages.

Employing quantitative autoradiography, pineal body glucose utilization (GU) was measured in daytime or at night in prepubertal (aged 1 month), adult (aged 3 months), and mature (over 12 months old) rats. In prepubertal and adult rats, in daytime, GU values within the pineal tissue were homogeneously distributed around 65 mumol glucose/100 g per min. In prepubertal animals no significant variations in GU were observed between daytime and nocturnal measurements. A circadian metabolic rhythmicity was evident in adult rats, with a GU peak measured at 2 a.m. In mature animals, GU also varied between day and night, with an increment in the relative difference between the two values. The present investigation is the first to demonstrate that circadian metabolic rhythmicity is absent before sexual maturation while it is enhanced in 12-month-old rats. These changes in pineal energy metabolism with advancing age are intriguing in view of the concept that the pineal gland may be involved in functional changes occurring during the process of aging.

Animals↗
PubMed1993

[Comparative anatomo-microscopic observations on the esophagus of teleosts with different feeding habits].

The authors describe the micro-anatomy of the oesophagus of different diet fish: herbivorous (Boops salpa), omnivorous (Liza aurata) and carnivorous fish (Blennius gattorugine and Gaidropsarus mediterraneus). In all the observed species the oesophagus is formed by a tunica mucosa, tunica muscularis and tunica serosa. The tunica mucosa of the herbivorous fish arises to form thin plicae which protrude into the lumen and are covered with squamous stratified epithelium. The goblet cells do not arrange among the covering cells but take place laterally and on the basis of the plicae. The tunica muscularis is constituted by an external circular layer and an inner longitudinal layer of striated muscle. The oesophagus of omnivorous fish shows thick plicae covered with a higher epithelium than that of the herbivorous fish. Among the epithelial cells a lot of taste buds have been found. The tunica muscularis is like that of the herbivorous fish. In the carnivorous fish Blennius the tunica mucosa presents thin plicae like those of the herbivorous fish but they are covered with a thicker epithelium. The tunica muscularis is formed by an external circular layer and by an inner longitudinal layer which constitutes two diametrically opposed bundles placed dorsally and ventrally. In the other carnivorous fish Gaidropsarus, the tunica mucosa shows very thick plicae covered with a quite high squamous epithelium among which there are many goblet cells. In this fish too numerous taste buds have been found. The tunica muscularis is arranged in the same manner observed in the other carnivorous fish.

Animals↗
PubMed1992

Morphometric analysis of sciatic nerve and its main branches in the rabbit.

In the rabbit the myelinated fibres with the largest diameter originating from the sciatic nerve distribute mainly into the peroneal nerve, even though there is no difference in the density of myelinated fibres of the representative unit between the sciatic nerve and its branches. The distribution of the myelinated fibre diameters is unimodal in the sciatic nerve, but bimodal both in the peroneal and tibial nerves. The quotient axon diameter/fiber diameter (g ratio) shows a different trend between the sciatic nerve and the branches originating from it. Except for the peroneal nerve, the increase of the axon calibre corresponds to the reduction of the relative myelin sheath thickness and therefore to the reduction of internodal distance. The results show that the sciatic nerve and its terminal branches in the rabbit have morphometrical characteristics that are peculiar and differ from those of the other rodents.

Animals↗
PubMed1991

Architecture of the myosalpinx of the isthmus in the guinea pig by means of scanning electron microscopy.

The three-dimensional architecture of the isthmic myosalpinx in the guinea pig was investigated by means of a technique that involves stretching the myosalpinx under a dissecting microscope, followed by selective digestion of the interstitial connective tissue with KOH and, finally, observation under a scanning electron microscope. The images obtained in this way prove that the myosalpinx is arranged in single bundles of smooth muscle cells which essentially do not show any specific geometrical course. Furthermore, smooth muscle cell bundles following an oblique course, not referred in the literature prior to this report, were demonstrated. These new three-dimensional microanatomical results call for a reevaluation of the functional role of oviduct motility.

Animals↗
PubMed1991

The three-dimensional architecture of the myosalpinx in the rabbit as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of the myosalpinx in the rabbit has been investigated by means of scanning electron microscopy after microdissection and the removal of interstitial connective tissue with KOH digestion. In the extramural portion of the tubo-uterine junction, the myosalpinx presents outer longitudinal bundles which form a well-defined continuous muscular layer extending towards the ampulla. Underlying this layer there are single muscular bundles which follow an uneven circular arrangement. At a deeper level the same bundles present a plexiform arrangement. Several bundles reach the base of the mucous folds and follow a discontinuous, approximately longitudinal arrangement. In the isthmus, the myosalpinx shows superficial longitudinal strips that abruptly bend sideways as they approach the ampulla, thereby enveloping the underlying muscular structure. The latter is arranged in the same way as at the extramural portion of the tubo-uterine junction, except for the lack of the outer longitudinal layer originating from the uterus. Our 3-D results revealed that the architecture of the rabbit myosalpinx consists of muscular bundles independent of one another that follow multiple spatial arrangements and form a complex network. Such a type of structure seems to be capable of stirring rather than pushing the embryo and gametes.

Animals↗
PubMed1989

An ultrastructural study of pigeon bursa of Fabricius during involution.

The ultrastructure of the pigeon bursa of Fabricius during involution is described. According to the AA, the involutive process may be divided into 3 stages: an early involutive stage, a late involutive stage and a residual stage. The involutive process starts from epithelium later affecting the follicular medulla and all other structures of the organ. A mucoid degeneration can be observed, followed by an impressive fatty degeneration.

Aging↗