Maria Giambelluca

Ultracytochemical localization of the NADPH-d activity in the human nasal respiratory mucosa in vasomotor rhinitis.

Objectives Description of the ultrastructural localization of nitric oxide synthase in the blood vessels of the nasal respiratory mucosa in patients with vasomotor rhinitis.

MPTP-induced Parkinsonism is associated with damage to Leydig cells and testosterone loss

Genital dysfunction and testosterone deficiency occur frequently in Parkinsons disease and represent a typical non-motor symptom of the disorder. Despite that, to our knowledge no study investigated whether at experimental level this can be reproduced with classic Parkinsonism-inducing neurotoxins. In this study we evaluated the effects produced in the testis following administration of the Parkinsonism-inducing neurotoxin 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine in mice. At 7 days following treatment, in the presence of a severe nigrostriatal dopamine depletion, we found a marked decrease in testosterone plasma levels in 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine-treated mice. Such testosterone loss occurred concomitantly with loss of Leydig cells and the presence of altered morphology in the interstitium with severe mitochondrial degeneration in spared Leydig cells. The loss of Leydig cells was accompanied by a marked decrease in TH immunohistochemistry and TH protein in the interstitium. This was accompanied by a significant decrease in norepinephrine levels in the testis. These effects shed novel light to understand genital dysfunction and testosterone deficiency in Parkinsonism, while offering a new experimental model to reproduce genital dysfunction in Parkinsons disease.

Distribution of 3-nitrotyrosine in the nasal polyps of atopic patients.

Objective To investigate whether formation of nitrotyrosine in the nasal polyps of atopic patients occurs.

Cytochemical localisation of the NADPH diaphorase activity in the Leydig cells of the mouse

Abstract The distribution of the NADPH diaphorase activity was studied in mouse Leydig cells by means of light and electron microscopy. When observed by the light microscope, most Leydig cells appeared intensely stained; a few cells (about 10%) showed a slightly positive or apparently negative reaction. The inhibitory effects of NG-nitro-l-arginine and iodonium diphenyl on frozen sections suggest the colocalisation of NADPH diaphorase reaction with nitric oxide synthase. The ultrastructural study revealed that all the Leydig cells were positively stained for NADPH diaphorase; however, a small number of cells displayed weak enzymatic activity. The reaction product was located in the mitochondria, smooth endoplasmic reticulum and lipidic vacuoles, and the nuclear envelope was also stained. The possible meaning of the NADPH diaphorase activity in the Leydig cells of mice was discussed.

Ultrastructural localization of the NADPH-diaphorase activity in the Leydig cells of aging mice

Recently, it has been shown that nitric oxide may inhibit the Leydig cell steroidogenesis. The present paper describes, by means of NADPH-diaphorase histochemistry, the ultrastructural localization of the enzyme nitric oxide synthase in the Leydig cells of young adult and aging mice. In the young adult mice, the enzymatic reaction was mainly located in the mitochondria and in some clustered cisternæ of the smooth endoplasmic reticulum. The nuclear envelope was faintly labeled. In the aging mice, most Leydig cells showed an enhanced enzymatic reaction. Labeled mitochondria were increased in number, and labeled areas of the smooth endoplasmic reticulum were more numerous and extended. In addition, a strong enzymatic reaction was recognized in the nuclear envelope. We conjecture that the impaired steroidogenesis observed in the testis of aging mammals might, at least in part, depend on the increased nitric oxide production in the Leydig cells.

Epixenosomes, peculiar epibionts of the ciliateEuplotidium itoi: Involvement of membrane receptors and the adenylate cyclase-cyclic AMP system in the ejecting process

SummaryThe extrusive apparatus is the most prominent and complex structure of epixenosomes. In the present paper the mechanisms activating its ejecting process were investigated by means of in vivo treatments and cytochemical procedures at the ultrastructural level. The results obtained clearly demonstrated that the ejecting process in epixenosomes is triggered by the detection of external signals through membrane receptors and the consequent activation of the adenylate cyclase-cyclic AMP system as a transduction mechanism. The membrane receptors coming into play have an affinity for soybean agglutinin and have a precise localization at the top of the organism, just where a membrane interruption appears as a first step in the whole process. The factors that trigger ejection in nature are still unknown. In the laboratory, ejection was obtained in the presence of adrenalin, which has been proved to bind to the same receptors shown to have affinity for soybean agglutinin. So epixenosomes appear to possess specific binding molecules for a mammalian hormone in the appropriate location, i.e., in the plasma membrane, and this hormone induces a precise biological response. These results are particularly interesting if we consider that epixenosomes are enigmatic organisms in which prokaryotic and eukaryotic characteristics appear to coexist.

Epixenosomes, peculiar epibionts of the ciliated protozoonEuplotidium itoi: what kind of organisms are they?

SummaryEpixenosomes live on the dorsal surface of their ciliate host,Euplotidium itoi. They lack a nuclear envelope and divide like prokaryotes. On the other hand they have a morphological and functional cell compartmentalization and possess tubules that are sensible to tubulin inhibitors and positively react with different antitubulin antibodies. In the present paper, as a first step to investigate their real nature, the in situ hybridization technique was applied at the ultrastructural level. Different prokaryotic and eukaryotic probes suitable for detecting rRNA genes were used. An additional test was performed with the gene encoding for β tubulin in the ciliateEuplotes crassus. Positive results, evidenced by a precise localization of gold particles, were obtained with all the eukaryotic probes used. These probes were obtained from organisms belonging to three different kingdoms (Protista, Animalia, Plantae). On the contrary, no hybridization was obtained with prokaryotic probes, not even when the probe used was an oligonucleotide complementary to all bacterial 16S rRNA so far sequenced. On the basis of these results and of the other observations so far accumulated, the possible eukaryotic nature of epixenosomes is discussed.

Ultrastructural Localization of NADPH-Diaphorase Activity in the Endothelial Cells of Human Nasal Respiratory Mucosa:

The cavernous sinuses are the most peculiar feature of the nasal angioarchitecture, due to their ability to retain a large quantity of blood in reply to a variety of topical and systemic stimuli. Recently, nitric oxide (NO) has seemed to be crucially involved in the nasal vascular regulation. The distribution of NO-synthase (NOS), the enzyme that catalyzes the formation of NO, was studied in the endothelium of nasal blood vessels by the ultracytochemical detection of reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) enzymic activity. The endothelium of the cavernous sinuses appeared strongly positive, whereas the endothelium of arterioles was occasionally labeled. The endothelial cells of capillaries and venules were found to be NADPH-d negative. The strong enzymic activity observed in the cavernous sinuses suggests a major role of NO in the capacitance vessels compared to the resistance vessels. The hypothesis of a reciprocal inhibition between the NOS enzymic pathways present in the respiratory epithelium and in the endothelium of cavernous sinuses is put forward. The nasal disorders characterized by anomalous vasomotility and vascular permeability could be caused in part by the irregular control of these complex interactions.

Ultrastructure of the supporting cells in the paratympanic organ of chicken, Gallus gallus domesticus.

The paratympanic organ is a specialized sensory organ of birds located in the medial wall of the tympanic cavity. It possesses a sensory epithelium formed by type II hair cells and supporting cells. The supporting cells are tall, narrow units that extend from the basement membrane to the free epithelial surface. They show a fine structure characterized by numerous mitochondria, a conspicuous Golgi complex and a well‐developed RER. Moreover, some uncommon structures, probably formed by heaped RER cisternae, are frequently present in the cytoplasm. Adjacent supporting cells are connected by numerous and extensive gap junctions; moreover, small gap junctions between hair cell and supporting cells are to be found. The possible mechanical and metabolical functions of the paratympanic organ supporting cells are discussed. J. Morphol. 236:65–73, 1998.

Chronic alcohol administration causes expression of calprotectin and RAGE altering the distribution of zinc ions in mouse testis

Abstract Several studies reported that chronic alcohol consumption alters the intestinal mucosa barrier, and subsequent entrance of endotoxins into the bloodstream. In many tissues endotoxin exposure causes the expression of calprotectin (CP) and the receptor for advanced glycation -end products (RAGE). In this study we investigated whether chronic alcohol administration causes expression of CP and RAGE in mouse testis. The distribution of free and loosely bound Zn2+ (FLB-Zn2+) in the testicular tissues was also evaluated. Alcohol-induced testicular damage was documented by measuring testosterone blood levels and by light and electron microscope studies. Twenty mice were treated daily for three weeks with 3.0 g/kg of a 25% solution of alcohol. Ten mice were treated in the same period of time with a solution of maltose dextrins, isocaloric to alcohol. Twenty untreated mice were used as controls. Alcohol treated mice showed diffuse expression of CP and RAGE in the interstitial cells. RAGE was found also in the basal compartment of the seminiferous tubules. Depletion of FLB-Zn2+ was observed in the adluminal compartment of the seminiferous tubules. Expression of CP and RAGE was not found in control mice and maltose dextrin treated mice. Our results indicated novel mechanisms by which alcohol acts in testis. Indeed, CP and RAGE may cause the generation of oxidants and inflammatory mediators, with negative impact on testicular functions. Depletion of FLB-Zn2+ may contribute to the dysregulation of spermatogenesis.