Biomedical subjects

R Puxeddu

Publications and source records attributed to R Puxeddu.

At least 19 recordsLinked to original sources

PubMed2005

Morphological alterations induced by cytochalasin D on serous cells of human submandibular gland in basal and stimulated conditions.

Cytochalasin D (CD) is a fungal toxin which binds to the faster growing end of actin microfilament and inhibits actin polymerization. By an in vitro incubation system of slices of human submandibular glands obtained at surgery, we investigated by light microscope (LM), transmission electron microscope (TEM), and high resolution scanning electron microscope (HRSEM) the morphological changes caused by CD on serous cells. We studied the effects of the drug on secretory events induced by isoproterenol (I) and carbachol (C). With LM, following CD incubation, canaliculi were enlarged and prominent vacuoles were seen throughout the cytoplasm. By TEM, the vacuoles, which in many cases were in continuity with the lumen, represented the distinctive feature of secretory cells. With HRSEM, intercellular canaliculi, seen from their cytoplasmic side, exhibited many small spherical bulges, corresponding to the coated pits seen with TEM and indicating that the retrieval of plasma membrane was arrested at an early phase by the disruption of the actin cytoskeleton. In specimens treated with secretagogues and CD, a consequence reported here for the first time was the presence of dense granules within the vacuoles. The protrusions seen by HRSEM on the cytoplasmic side of intercellular canaliculi, following secretagogues stimulations, appeared peculiar to each stimulants, even if combined with CD, suggesting that besides actin filaments, other components, unaffected by CD, also are involved in the process of exocytosis and related phenomena.

Actin Cytoskeleton↗

PubMed2005

Revision stapes surgery for recurrent transmissional hearing loss after stapedectomy and stapedotomy for otosclerosis.

A total of 20 stapedotomy and 24 stapedectomy cases were retrospectively reviewed to establish the causes of failure, and to evaluate hearing results after revision surgery. Our series included 23 male and 21 female patients. Mean age at revision time was 42 years, and the mean interval from primary surgery and revision stapes surgery was 27 months. The retrospective review of our data, revealed that the most common cause for revision surgery was a displaced prosthesis (47.7%). After revision surgery, the mean post-operative air-bone gap was 14.78 dB. A mean post-operative air-bone gap within 10 dB occurred in 24 patients (54.5%), in 14 patients (31.5%) this was between 11 and 20 dB, in 5 patients (11.5%) between 21 and 30 dB, and in one patient (2.5%) > 30 dB. There were no "dead ears" in this series. Our results compare to other reported series, and confirm that after revision stape surgery, an air-bone gap closure within 10 dB is difficult to obtain. In the present series, the use of the total ossicular replacement prosthesis resulted in the poorest functional hearing results.

Adolescent↗

PubMed2003

Serous and mucous cells of human submandibular salivary gland stimulated in vitro by isoproterenol, carbachol and clozapine: an LM, TEM, and HRSEM Study.

We have investigated by LM, TEM, and HRSEM the effects of D,L-isoproterenol (beta-adrenergic agent), carbachol (muscarinic agent) and clozapine on biopsy specimens of human submandibular gland stimulated in vitro in an inorganic oxygenated medium. Clozapine is a dibenzodiazepine derivative used in psychotic patients that provokes hypersalivation, a displeasing side effect that often causes discontinuance of therapy. Our findings demonstrate that clozapine acts on salivary mucous and seromucous (serous) cells of the gland as a muscarinic agonist. However, the induced secretory response seems to differ qualitatively and quantitatively from that resulting from carbachol. Thus, in agreement with published data resulting from therapeutic treatments and from experimental studies on rats, the mechanism of clozapine induced hypersialorrhea remains open to further investigation.

Adrenergic beta-Agonists↗

PubMed2003

Dose-dependent morphological changes of intercellular canaliculi during stimulation with carbachol and isoproterenol in the isolated rat submandibular gland.

Intercellular canaliculi (IC) form a primary mixing reservoir for transcellularly and paracellularly secreted saliva whose composition depends on the degree of elevation of cytosolic Ca2+ and of cytosolic cyclic AMP concentrations caused by the secretagogues employed. In perfused rat submandibular gland (SMG), appearance of exocytosis on IC reflected the quantity of secreted mucin. Morphological observations were carried out by HR-SEM using a modified osmium maceration method on specimens treated with CCh and/or ISP. Mild secretory stimulation revealed that exocytosis did not occur simultaneously, even along the same intercellular canaliculus. Higher doses did not alter the spatial distribution of exocytosis along intercellular canaliculi but increased its temporal frequency, dose dependently. These findings lead us to conclude that, under low levels of secretory stimulation, exocytosis does not show a dose-dependent change, but that its spatial and temporal frequency changes in a dose-dependent manner.

Adrenergic beta-Agonists↗

PubMed2003

Localisation of epidermal growth factor receptor in mucous cells of human salivary glands.

EGFR activation has been related to an increase in synthesis and secretion of mucins in epithelial cells, so that the use of EGFR tyrosine kinase inhibitors has been proposed in the therapy of mucin hypersecretory diseases. In this paper, we describe the ultrastructural localisation of EGFR in the mucous elements of human major and minor salivary glands and relate it to mucin distribution. A post-embedding immunogold staining method has been applied to normal surgical samples of human submandibular, sublingual, and labial glands, using a mouse monoclonal antibody specific for the intracellular domain of human EGFR. In mucous cells of all the glands examined, specific reactivity was detected in the cytoplasmic basolateral portions and near the mucous droplets, but not on cell surfaces. Since this pattern of labelling must be related to the internalisation process of the ligand-GFR complex, our results support the hypothesis that EGFR activation takes place in mucous cells and affects mucin production in human salivary glands.

Adult↗

PubMed2003

Endoscopic CO2 laser treatment of supraglottic carcinoma.

Aim of the study was to evaluate whether laser endoscopic microsurgery is a reliable and appropriate approach to treatment of laryngeal supraglottic cancer. A retrospective study was made of 12 patients (11 M/1 F; mean age 62.5 years) treated from December 1995 to October 2001 in the Department of Surgical Sciences and Organ Transplantations, Section of Otorhinolaryngology, University of Cagliari, Italy. Surgical steps and oncologic results are reported. These 12 patients with supraglottic cancer underwent transoral laser surgery (TNM classification: T1, 3 patients; T2, 9 patients; N-, 9 patients; N+, 3 patients; M-, 12 patients). On the basis of the different subsites removed, the following resections were performed: 1 limited excisional biopsy (false chord), 3 wide excisional biopsies (2 or 3 subsites), 2 simple epiglottectomies, 1 extended epiglottectomy, 3 horizontal supraglottic laryngectomies, and 2 horizontal supraglottic laryngectomies that were extended to the anterior commissure and to one arytenoid, respectively. Five patients underwent functional neck dissection, and one patient underwent post-operative radiotherapy at sites of tumour and lymph nodes. Temporary tracheotomy was carried out in 10 patients. Mean follow-up was 33.3 months. No local recurrences were noted. Local control was thus 100%. Aspiration was the main post-operative problem, but there were no cases of aspiration-associated pneumonia. Moreover, no patient needed laryngectomy or a permanent tracheotomy for aspiration. In conclusion, although our experience with supraglottic cancers treated by endoscopy is still too limited to confirm the definitive oncologic validity of this type of surgery, in our hands, it seems to be a reasonable tool in selected cases and a safe, time- and cost-effective alternative to traditional surgery or radiotherapy for selected supraglottic carcinomas.

Aged↗

PubMed2002

Intralobular ducts of human major salivary glands contain leptin and its receptor.

Leptin, a 16-kDa hormone, plays an important role in the control of food intake and in energy homeostasis both in rodents and in man. Leptin is mainly produced and secreted by adipocytes, but other tissues and gastric glands have also recently been shown to produce it in a dual (endocrine and exocrine) mode. In addition, a leptin receptor has been detected in taste cells of mouse circumvallate papillae and in rat intestinal epithelium. These data prompted us to carry out a detailed study of human salivary glands as potential leptin-producing organs. Biopsies of salivary glands (submandibular and parotid) obtained from male and female patients during surgery for different clinical indications were subjected to immunohistochemical study for the presence of leptin, its functional receptor, insulin and glucagon. The presence and cellular distribution of glucocorticoid receptor in leptin-secreting cells were also investigated. Double immunohistochemical staining (silver-gold intensification and avidin-biotin-peroxidase) was used for the visualization of glucocorticoid receptor and leptin labelling, respectively. The results show that intralobular duct cells of submandibular and parotid glands are immunoreactive for leptin, leptin receptor and glucagon but not for insulin. Leptin was also detected in some microglobules in whole saliva obtained from four healthy volunteers. Co-localization for leptin, leptin receptor and glucocorticoid receptor in the same cell type suggested a functional relationship between glucocorticoid hormone and leptin secretion also at the level of the salivary glands.

Adult↗

PubMed2002

Morphofunctional studies on human labial salivary glands.

In this study, the first experimental investigation carried out at the ultrastructural level on mucous cells of human salivary glands, we have examined by light microscopy (LM), transmission electron microscopy (TEM), high resolution scanning electron microscopy (HRSEM), the secretory response of labial glands stimulated in vitro by the beta-adrenergic agent, D,L isoproterenol, and by the muscarinic agent carbachol. For comparison we have used identical methods to study samples of mixed portions of human submandibular glands. Morphological findings obtained here on both submandibular and labial glands mucous cells demonstrate that mucous droplets are released solely by muscarinic stimulation, and that cytological events occurring during secretory discharge are similar to those described by others, using TEM, on stimulated mucous cells of rat sublingual glands. Despite the fact that human labial glands are said to have a prominent cholinergic innervation with scanty adrenergic nerves, the response of seromucous cells in these organs to stimulation with carbachol and with isoproterenol was similar to that observed by us, (using LM, TEM and HRSEM), in serous cells of human major salivary glands.

Adult↗

PubMed2000

A high resolution sem study of human minor salivary glands.

By SEM we have investigated the human minor salivary glands using the NaOH method for the visualization of endpieces and myoepithelial cells, and the osmium maceration technique that reveals membranous intracellular structures. With the former method all minor glands, including the posterior deep (Ebner's) lingual glands, consist of tubules sometimes dilated into alveoli, while true acini of the kind observed in human major salivary glands, are absent. Tubules of the posterior deep lingual gland exhibit stellate myoepitelial cells that leave a substantial part of the secretory cells uncovered. The latter cells, at variance with serous cells of major glands, do not show basal folds. In contrast, tubules of the other minor glands, like the mucous ones of major glands, are covered almost completely by band-like myoepithelial cells. The osmium maceration method clearly demonstrates that posterior deep lingual glands are serous in character and that all the other minor glands, together with the predominant mucous cells, possess a variable number of seromucous cells that, despite variations among individuals, increase in order from palatine and posterior superficial lingual (Weber's), to minor sublingual, labial, anterior lingual (Blandin and Nuhn's), and buccal glands.

Humans↗

PubMed2000

Cell biology of human salivary secretion.

We treated surgical specimens of human parotid and submandibular glands in vitro to manipulate the receptor-signaling cascade pharmacologically and analyzed cellular responses by light microscopy on epoxy embedded sections. Treatment of specimens with the b-agonist, isoproterenol, and with the second messenger analog, dibutyryl cyclic AMP, stimulated serous acinar cells to engage in exocytosis and degranulation. The muscarinic agonist, carbachol, and the calcium ionophore, A23187, on the other hand, elicited formation of "vacuoles" in the cytoplasm of serous acinar cells. Taking previous in vivo human and animal studies into account, these changes are suggested as the morphological expression of enzyme release and fluid secretion, respectively. Specimens obtained from patients over 70 years old exhibited poor response even though their morphological appearance remained intact. Aged salivary glands are thus suggested to experience a decline in their secretory activity at the cellular level, probably by impairment of the signaling processes downstream to the receptor activation and second messenger production.

Adrenergic beta-Agonists↗

PubMed2000

The presence of a local immune system in the upper blind and lower part of the human nasolacrimal duct.

The nasolacrimal duct is exposed to exogenous agents, including potentially harmful microorganisms, coming from the eye surface by the lacrimal sac, and from the nasal cavity by the inferior meatus of the nose. The upper blind and lower part of the human nasolacrimal duct were examined immunohistochemically to ascertain the presence and localization of immunoglobulin-producing cells and the epithelial expression of IgA, IgM, and IgG in order to verify the possible antimicrobial properties of this duct. IgA-, IgM-, and IgG-positive immunocompetent cells were recognizable in the lamina propria of the upper blind and lower part of the human nasolacrimal duct, while an evident immunoreactivity for sIgA, IgM, and IgG was demonstrated in the cytoplasm of the apical epithelial cells. The results suggest that all the effector components of the mucosal immune system are present in that area of the human nasal mucosa next to the opening of the nasolacrimal duct as well as in the human lacrimal sac.

Adolescent↗

PubMed2000

Endoscopic revision of failed external dacryocystorhinostomy.

Obstruction of the lacrimal pathways is a relatively frequent problem usually corrected by external dacryocystorhinostomy. Failure of the external approach may be due to an inadequate rhinostomy, excessive scar tissue production, anatomical anomalies or concomitant paranasal sinus infectious. The introduction of direct and angled endoscopes for paranasal sinus surgery and the refinement of endoscopic surgical procedures allows a complete intranasal exposure and surgical management of the lacrimal sac, even in cases of recurrent obstruction. The present work offers a retrospective review of the records of seven patients who underwent a revision endoscopic dacriocystorhinostomy (ENDCR) between January 1994 and June 1997 for failed external dacryocystorhinostomy. The preoperative evaluation of the patients, the surgical technique and the postoperative management are examined in detail. A permanent dacryocystorhinostomy was obtained in six patients. One patient underwent a successful bilateral procedure. One patient experienced a persistent stenosis. There were no complications related to the surgical procedure. In our experience the revision endoscopic dacryocystorhinostomy offered several advantages, including a complete exposure of those anatomical anomalies or inflammatory changes of the normal structures that commonly hinder conventional external surgery. Although a larger series will further elucidate the efficacy of this procedure in failed external dacryocystorhinostomy, we recommend considering revision ENDCR as an alternative to the external revision technique.

Adult↗

PubMed2000

A randomized controlled trial showing efficacy of once daily intranasal budesonide in nasal polyposis.

A randomized, double-blind, placebo-controlled trial was performed to assess the efficacy of once daily budesonide in patients with nasal polyps. After a 2-week run-in period, 157 patients with symptomatic bilateral nasal polyposis were randomized to receive budesonide, 140 micrograms once or twice daily or 280 micrograms once daily (delivered doses) via Turbuhaler, or placebo for 8 weeks. Polyp size was assessed endoscopically and, in two centres, by magnetic resonance imaging (MRI). Nasal symptoms (blocked nose, runny nose, sneezing) were recorded daily, and patients provided an overall assessment of efficacy at the end of the study. Budesonide, 280 micrograms/day (280 micrograms o.d. and 140 micrograms twice daily), significantly reduced polyp size, compared with placebo, whereas budesonide, 140 micrograms once daily, had no significant effect. Nasal polyp mass score, measured by MRI, was also significantly reduced in patients receiving 280 micrograms/day. All three doses of budesonide significantly reduced symptom scores, and there were no significant differences between the groups. Overall, approximately 70% of patients receiving budesonide, 280 micrograms/day, reported substantial or total control of symptoms, compared with 45% of placebo-treated patients. It is concluded that budesonide, 280 micrograms once daily, reduces polyp size and relieves symptoms in patients with nasal polyposis.

Administration, Intranasal↗

PubMed1999

A scanning and transmission electron microscope study of the human minor salivary glands.

All human minor salivary glands, apart from the posterior deep lingual (von Ebner's) glands which were serous, contained a minor population of seromucous cells that increased from palatine and posterior superficial lingual (Weber's) to labial, anterior lingual (Blandin and Nuhn's) and buccal glands, in that order. Unlike the predominant mucous cells, whose structure was uniform, serous and seromucous cells exhibited, in each gland, peculiar cytological and cytoarchitectural characters.

Adolescent↗

PubMed1998

Exocytosis in human salivary glands visualized by high-resolution scanning electron microscopy.

The luminal membrane of salivary acinar cells creates a specialized cell surface area that accepts exocytosis and undergoes dynamic changes during secretion. These changes were visualized three-dimensionally from both the inside and outside of the cell in human parotid and submandibular glands, by application of in vitro secretory stimulation and then of OsO4 maceration to remove cytoplasmic organelles by varying degrees. In control glands treated without secretagogues, the luminal surface of serous acinar cells bore well-developed microvilli with only an occasional incidence of exocytotic profiles. Following treatment with the beta-adrenergic agonist, isoproterenol, considerable shortening and loss of microvilli occurred along the luminal membrane where, on its cytoplasmic side, many protuberances of sizes similar to or smaller than those of single secretory granules (approximately 1 micron in diameter) appeared. The cytoplasmic surface of these protuberances exhibited small vesicles (approximately 100-150 nm in diameter) that, by transmission electron microscopy, were shown to be coated pits or vesicles present on or around the exocytosed granule membranes. Treatment of tissues with the muscarinic agonist carbachol also caused a decrease of microvilli and the appearance of protrusions at the luminal membrane. However, unlike isoproterenol treatment, many of these protrusions were devoid of small pits or vesicles and were much larger than a single secretory granule. These results indicate that (1) secretory stimulation causes the dynamic transformation of microvilli at the luminal membrane, where granule docking and membrane fusion take place, and (2) after fusion, the exocytosed membranes are processed differently, by coated pit/vesicle mediated or non-mediated mechanisms, according to the autonomic receptor control.

Adrenergic beta-Agonists↗

PubMed1998

Immunohistochemical localization of secretory immunoglobulins in the main excretory duct of the human submandibular gland.

The localization of IgA, IgG, and IgM was investigated immunohistochemically in the mucosal surface of the main excretory duct of the human submandibular gland in order to verify the possible antimicrobial properties of this duct. Only secretory IgA-immunoreactivity was recognized in the epithelial cells of the duct. An intense immunoreactivity was observed in the cytoplasm of some cells and at the luminal surface of most of the cells. Clusters of IgA-positive immuno-competent cells were also recognizable in the subepithelial layers. No reactivity for IgG and IgM was noticed. The results suggest that the ductal epithelium may actively be involved in the release of secretory IgA, which could play a prominent role in the local defense mechanism of the duct.

Adult↗

PubMed1998

Polymorphous low-grade adenocarcinoma of the parotid gland.

Polymorphous low-grade adenocarcinoma of the salivary glands is a well-defined clinico-pathological entity which occurs almost exclusively in the oral cavity. Only few reports have documented it in the parotid gland. The authors report an additional case of de novo polymorphous low-grade adenocarcinoma of the parotid and describe the histological and immunocytochemical features of the neoplasm. The current literature is also reviewed.

Adenocarcinoma↗

PubMed1997

Colon adenocarcinoma metastatic to the larynx.

Secondary neoplasms of the larynx are rare and account for 0.09 to 0.4% of all laryngeal tumors. These tumors can occur by hematogenous or lymphogenous spread and may represent a diagnostic dilemma when the laryngeal localization is the only manifestation of disease. When multiple metastases are present, the appropriate treatment becomes even more controversial. To our knowledge only 148 cases of metastatic laryngeal neoplasms have been reported in the literature, with cutaneous melanomas and carcinomas from the kidney representing the most frequent primary sites of origin. Our research of the available literature has shown that only nine cases of metastases from colon adenocarcinomas have been described. In general, the overall prognosis of patients with a secondary laryngeal tumor is poor, since involvement of the larynx by a distant tumor commonly occurs in the terminal phase of the primary disease process. As such, the aim of treatment frequently is only to improve the quality of life of the patient. We report a case of colon adenocarcinoma metastatic to the larynx and discuss the problems related to its pathogenesis, diagnosis and treatment.

Adenocarcinoma↗