Francesco Giannessi

Effect of microwave radiation on Bacillus subtilis spores

Aims:  To compare the killing efficacy and the effects exerted by microwaves and conventional heating on structural and molecular components of Bacillus subtilis spores.

Ultrastructural and ultracytochemical study of the human nasal respiratory epithelium in vasomotor rhinitis

Objectives—Several pieces of evidence have suggested that nitric oxide (NO) fulfills important functions in the respiratory mucosa, under both normal and pathological conditions. This study was performed to investigate the role of NO in the nasal respiratory epithelium of patients affected by vasomotor rhinitis. The structure and ultrastructure of the epithelium were also examined. Material and Methods—The localization of NO synthase activity was determined by means of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase ultracytochemistry. Nasal mucosa was obtained from patients who had undergone surgical therapy for reduction of the inferior turbinate. Results—Examination of hematoxylin–eosin-stained sections revealed that most of the nasal mucosa covering the surgical samples was characterized by severe epithelial damage. The ultrastructural study confirmed the light microscopic observations. Ciliary loss, absence of the intercellular junctions and distension of the intercellular spaces were found in the damaged epithelium. The basement membrane was frequently interrupted. Some epithelial cells were identified as basal cells. Other cells of the damaged epithelium were probably involuted ciliated and goblet cells. The ultracytochemical study showed that the basal cells were NADPH-diaphorase-negative in healthy subjects and strongly NADPH-diaphorase-positive in subjects with vasomotor rhinitis. Conclusions—It is suggested that NO has cytotoxic effects and causes inhibition of mitotic activity in the basal cells, leading to epithelial disruption and breakdown of the protective functions of the epithelium.

Cytokine secretion in nasal mucus of normal subjects and patients with allergic rhinitis

Allergic rhinitis is regulated by the local production and release of several cytokines. The levels of Th2 cytokines IL-4, IL-6, IL-10 and the Th1 cytokine IFN-gamma were studied in nasal mucus from 30 subjects with allergic rhinitis and 45 non-atopic healthy controls. In this study a sampling technique for collecting nasal mucus, well tolerated by the subjects and with a minimal stimulation of the mucosa, was performed. The cytokine concentrations in nasal mucus samples were detected and quantitated by a new paramagnetic particle-based immunofluorescent assay system more sensitive than the conventional ELISA techniques. The new technique showed reliable values of the measured parameters. The nasal mucus from allergic patients contained significantly higher concentrations of IL-4 (25.5 +/- 3.6 pg/ml; P < 0.001) and IL-10 (1300 +/- 190 pg/ml; P < 0.05) compared to the nasal mucus from control subjects (15.2 +/- 2.3 and 532 +/- 28 pg/ml, respectively, for IL-4 and IL-10). No significant modification in IFN-gamma levels of allergic patients was found when compared to control group (respectively, 19.9 +/- 3.3 vs. 25.7 +/- 5.1 pg/ml; P > 0.05). Moreover, the allergic patients showed lower levels of IL-6 concentrations in the nasal mucus compared to control subjects (64.8 +/- 9.1 vs. 129.0 +/- 18.1 pg/ml; P = 0.0099). These data can be interpreted by the hypothesis that in response to environmental allergens there is a preferential Th2 polarity by activated CD4+ T cells and that the cytokines IL-6 and IL-10 have, respectively, an important anti-inflammatory and counterregulatory action in the pathogenesis of allergic rhinitis.

The paratympanic organ: a barometer and altimeter in the middle ear of birds?

A century has passed since the discovery of the paratympanic organ (PTO), a mechanoreceptive sense organ in the middle ear of birds and other tetrapods. This luminal organ contains a sensory epithelium with typical mechanosensory hair cells and may function as a barometer and altimeter. The organ is arguably the most neglected sense organ in living tetrapods. The PTO is believed to be homologous to a lateral line sense organ, the spiracular sense organ of nonteleostean fishes. Our review summarizes the current state of knowledge of the PTO and draws attention to the astounding lack of information about the unique and largely unexplored sensory modality of barometric perception.

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.

The ultrastructure of the sensory hairs of the paratympanic organ receptor cells in chicken

The hair bundle of the receptor cells in the paratympanic organ of the chicken was studied by TEM, after fixation in aldehydes/osmium tetroxide or in aldehydes/osmium tetroxide/tannic acid. The bundles are formed by a kinocilium and by 40–70 stereocilia. The stereocilia are linked to each other by an extensive network of filaments. Three types of these connectors are present: basal, shaft and apical; the latter consist of side-to-side and tip-to-side connectors. We observed that the shaft connectors are well-highlighted only when tannic acid was used, while the other connectors are to be found in the conventionally fixed specimens also. The tip-to-side connector consists of a filament which joins the tip of a stereocilium with the side of an adjacent taller stereocilium; we suggest that the distortion of this filament would give rise to the mechanosensory transduction. The other connectors probably serve to maintain the regular spatial arrangement of the hair bundle and the mechanical coupling of the stereocilia. Our study shows that the general conformation of the hair bundle and the stereociliary links of the hair cells in the paratympanic organ of chicken are similar to those previously described in the hair cells of the acoustico lateralis system.