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Biomedical subjects

P Poggi

Publications and source records attributed to P Poggi.

At least 19 recordsLinked to original sources
PubMed2006

Histological evaluation of buccal penetration enhancement properties of chitosan and trimethyl chitosan.

The aim of the present work was to compare the penetration enhancement properties of chitosan hydrochloride (HCS) both as a polymeric solution and as a nanoparticulate system with that of trimethyl chitosan hydrochloride (TMC) on buccal mucosa. The hydrophilic high molecular weight fluorescein isothiocyanate dextran (FD4; 4400 Da) was used as a macromolecule model. The mechanism involved in the HCS (solution and nanoparticles) and TMC solution penetration enhancement was investigated on pig buccal mucosa, characterized by having stratified epithelium and lacking in tight junctions. The permeation/penetration of FD4 and the change in morphology and histology of the mucosa after contact with the polymers were assessed: the experiments were performed ex-vivo by applying the formulations on excised porcine buccal tissue. For the morphology and the histology studies, the epithelial cell layers from freshly excised pig buccal mucosa were analysed with light microscopy by means of routine histopathology analysis (haematoxylin and eosin staining and Toluidine blue staining) and immunohistochemistry reactions. The organization of desmosomal junctions was assessed by means of an immunochemical reaction on desmosomes and transmission electron microscopy. Confocal laser scanning microscopy (CLSM) was used to find evidence of the location of FD4 in the tissue. Furthermore, the increase of the FD4 apparent permeability coefficient was quantified by means of Franz diffusion cells using isolated buccal epithelium to demonstrate the penetration enhancement properties of the polymer systems. Morphological analysis, performed by light microscopy, transmission electron microscopy and CLSM, suggests a similar mechanism of penetration enhancement for both HCS and TMC solutions and for HCS nanoparticles. Such a mechanism probably involves a repackaging of the epithelial cells up to the basal membrane and a partial disarrangement of desmosomes. The cell viability and the nuclear integrity indicated on the semi-thin section stained with Toluidine blue and by CLSM analysis, respectively, suggest that HCS as a polymer solution and a nanoparticulate system, and TMC polymer solution, do not cause cell damage. Trimethyl chitosan and chitosan nanoparticulate systems were able to increase FD4 permeation across buccal epithelium to a greater extent than the chitosan solution.

Administration, Oral↗
PubMed2005

Nelfinavir in HIV-HCV coinfected patients: a 24-month follow-up in a cohort of 82 patients.

This retrospective and longitudinal study evaluated the long-term hepatic tolerance of a nelfinavir (NFV)-antiretroviral combined regimen in 82 patients of the HCV-HIV Cohort of CISIH-Sud of Marseilles. Follow-up data (liver enzyme levels, CD4 cell count, HIV viral load, and metabolic parameters) of patients treated with NFV on inclusion or during the follow-up of the cohort were analyzed under treatment over 24 months. Comparisons were performed with X2 or Kruskal-Wallis tests. At baseline (n = 82), the median exposure to NFV was 4.1 months; 58 patients received NFV combined with NRTI and 24 with NNRTI. The median CD4 cell count was 337/mm3 [interquartile range (IR): 216-480) and 39.7% had an undetectable HIV RNA level. Qualitative HCV PCR was positive in 91% of the patients and 19/51 patients with liver biopsy were F3-F4. Median alanine and aspartate aminotransferase (ALAT, ASAT), gamma-glutamyltransferase (GT), and alkaline phosphatase (ALP) were 46 UI/liter (IR: 36-76), 55 UI/liter (IR: 32-97), 97 UI/liter (IR: 50-194), and 88 UI/liter (IR: 72-104), respectively, with 76% of the patients with ALAT/ASAT grade <2. Median follow-up was 23 months (IR: 13.8-37). No significant difference was observed in the distribution of ALAT, ASAT, GT, and ALP as well as of ALAT/ASAT grades over the 24-month study period. Patients treated with NFV + NNRTI had significantly higher GT and ALP levels at baseline with no significant increase during follow-up. Cholesterol, triglyceride, and glycemia distributions remained stable over time. In conclusion, this study showed a good hepatic and metabolic tolerance of a long-term NFV-combined regimen in HIV-HCV coinfected patients.

Adult↗
PubMed2003

Reduction of oral acetaldehyde levels using a controlled-release chlorhexidine chip as a prevention strategy against upper digestive tract cancer.

Increasing evidence indicates a strong relationship exists between harmful habits like smoking and alcohol drinking and upper digestive tract cancer. In addition, smokers and alcohol drinkers also exhibit high salivary levels of carcinogenic acetaldehyde, the first metabolite of alcohol. This compound has been indicated as a major cancer causing factor in the upper digestive tract, especially among alcohol drinkers. Interestingly, acetaldehyde is produced from alcohol present in the epithelia by mucosal alcohol dehydrogenases (ADH) in the upper digestive tract. However, much higher levels derive from the bacterial oxidation of alcohol by the oral microflora. In this respect, the reduction of oral microbes can become a fundamental factor in diminishing the risk of cancer. In this article, we hypothesize that the antimicrobial agent chlorhexidine, formulated as controlled-release chip, and fixed by a dental device, (i.e., a modified orthodontic bracket), may be the most rational strategy for reducing acetaldehyde production by microflora.

Acetaldehyde↗
PubMed2002

The volatile fraction of cigarette smoke induces alterations in the human gingival fibroblast cytoskeleton.

Several in vitro investigations have indicated that the particulate phase of cigarette smoke, such as nicotine, affects many cell types, including gingival fibroblasts. However, few studies have been performed on the effects of the volatile fraction on the cellular structures that are involved in cell functions, such as adhesion and proliferation. Since the survival and reproduction of gingival fibroblasts are fundamental in maintaining the integrity of the oral connective tissue, as well as in wound healing, the effects on the cytoskeleton of acrolein and acetaldehyde, which are the volatile fractions of cigarette smoke, were examined in vitro for human gingival fibroblasts (HGFs). HGF strains that were taken from healthy subjects with non-inflamed-gingiva were utilized in this investigation. The cells were incubated in the presence of different concentrations of acrolein and acetaldehyde. Cell adhesion and viability were evaluated after incubation for 3 h and 5 days, respectively. The influence on cytoskeletal structures (tubulin, actin and vimentin intermediate filaments) was investigated with the indirect immunofluorescence technique. The results show that both substances produced similar effects, which resulted in a dose-dependent inhibition of HGF adhesion and viability. Disturbance of the HGF cytoskeleton consisted of disruption of the microtubules, actin filaments and vimentin microfilaments, which was accompanied by alterations to cell shape. Our experimental findings suggest that the volatile fractions of cigarette smoke, such as acrolein and acetaldehyde, have a cytotoxic effect on HGFs, with the result that they lose their capacity for adhesion and proliferation. The consequences of this could be impairment of the maintenance, integrity and remodelling of the oral connective tissue. According to our morphological evidence, these findings show that cigarette smoke can lead to the development and progression of periodontal disease, and indicate the need for appropriate therapy.

Acetaldehyde↗
PubMed2001

Microtubules and vimentin associated filaments (VIFs) in cultured human gingival fibroblasts (HGFs) after exposure to acrolein and acetaldehyde.

Tobacco smoke, particularly its non-volatile fraction e. g. nicotine, is considered to be a major risk factor for the development and progression of periodontal disease. The purpose of this study has been to determine the effects of acrolein and acetaldehyde of the volatile fraction of tobacco smoking, on human gingival fibroblasts (HGFs) cultured in vitro with particular attention to cytoskeletal structures. A human gingival fibroblast strain derived from healthy gingiva was utilized in this study. The cells were exposed to acrolein and acetaldehyde at various concentrations. Control and treated cells were compared as regards their adhesion on cell culture dishes. Their cytoskeletal structures [tubulin and vimentin intermediate filaments (VIFs)] were examined by fluorescence microscopy. The results revealed that both substances produced similar effects resulting in a dose dependent decrease in cell adhesion and alterations of HGF cytoskeleton consisting of rearrangement and/or disruption of microtubules and vimentin associated filaments. Changes in cell shape and decrease in cell size were also seen. On the basis of this in vitro study, it appears that tobacco, through its volatile components, may directly affect the main functions of HGFs.

Acetaldehyde↗
PubMed2001

Human gingival fibroblast cytoskeleton is a target for volatile smoke components.

BACKGROUND: Several in vitro investigations have indicated that the particulate phase of cigarette smoke as nicotine affects many cell types including gingival fibroblasts, but few studies have examined the effect of volatile fraction on cellular structures involved in cell functions such as adhesion and proliferation. Since gingival fibroblast survival and reproduction are fundamental to maintaining the oral connective tissue as well as to wound healing, the effects of acrolein and acetaldehyde, volatile fractions of cigarette smoke, on cytoskeleton were examined in human gingival fibroblasts (HGFs) in vitro. METHODS: Human gingival fibroblast (HGF) strains from healthy subjects with non-inflamed gingiva were utilized. The cells were incubated in different concentrations of acrolein and acetaldehyde. Cell adhesion was evaluated after 3 hours. The influence of both substances on cytoskeletal structures, tubulin and vimentin intermediate filaments (VIF), was investigated using indirect immunofluorescence technique. RESULTS: The results show that both substances produced similar effects, resulting in a dose-dependent inhibition of HGF adhesion. Disturbance of HGF cytoskeleton consisted of a disruption of microtubules and vimentin microfilaments with alterations in cell shape. CONCLUSIONS: Our experimental findings suggest that volatile fractions of cigarette smoke such as acrolein and acetaldehyde, because their ability to bind and interact with the cytoskeleton, prevent HGF adhesion. Consequently the maintenance of the oral connective tissue and integrity and remodeling could be impaired. According to our morphological evidence, these findings confirm other clinical and epidemiological investigations reporting that volatile components of cigarette smoke could lead to the initiation and progression of periodontal disease.

Acetaldehyde↗
PubMed2000

Ultrastructural changes in human gingival fibroblasts in vitro after exposure to vapour phase smoke components.

Tobacco and some of its volatile and non-volatile components have been found to affect many types of cells including gingival fibroblasts. Because normal gingival fibroblast functioning is fundamental to the maintenance of the oral connective tissue as well as to wound healing, we examined the effect of two vapour phase smoke components (acrolein and acetaldehyde) on proliferation and ultrastructure of human gingival fibroblasts (HGFs) in culture. A human gingival fibroblast strain derived from healthy individuals was used in this study. The cells were incubated in the presence of different concentrations of acrolein and acetaldehyde and cell proliferation and fine morphology were evaluated. The results show that acrolein and acetaldehyde produced dose dependent inhibition of HGF viability and alteration of cytoplasmic organelles. The main ultrastructural finding for the HGF cytoplasm was the presence of vacuoles and lysosomal structures which became prominent with increasing concentration of acrolein and acetaldehyde. Our results suggest that the ultrastructural alterations we observed in HGFs may be due to the uptake and storage of acrolein and acetaldehyde by the cells.

Acetaldehyde↗
PubMed2000

Volatile components of cigarette smoke: effect of acrolein and acetaldehyde on human gingival fibroblasts in vitro.

BACKGROUND: Tobacco and some of its volatile and non-volatile components have been found to affect many types of cells including gingival fibroblasts. Since normal gingival fibroblast functioning is fundamental to the maintenance of the periodontal connective tissue, as well as to wound healing, we examined the effect of acrolein and acetaldehyde, volatile components of cigarette smoke, on proliferation, attachment, and ultrastructure of human gingival fibroblasts (HGFs) in culture. METHODS: Human gingival fibroblast (HGF) strains derived from healthy individuals with non-inflamed gingiva were used in this study. The cells were incubated in the presence of different concentrations of acrolein and acetaldehyde. Cell attachment and proliferation were evaluated after incubation for 3 hours and 5 days, respectively. In addition, the cells were examined with a transmission electron microscope in order to evaluate their morphology. RESULTS: The results show that acrolein and acetaldehyde produced dose-dependent inhibition of HGF attachment and proliferation. The cytotoxic effect was, however, reversible when both substances were removed, after 3 days, from the medium. The main ultrastructural finding for the HGF cytoplasm was the presence of vacuoles and lysosomal structures that became prominent with increasing concentration of acrolein and acetaldehyde. CONCLUSIONS: Our experimental data suggest that acrolein and acetaldehyde, volatile components of tobacco smoke, are detrimental to HGF survival and consequently to the oral connective tissue. According to our morpho-functional evidence, these findings corroborate clinical and epidemiological investigations demonstrating smoke as a risk factor in the development of periodontal disease.

Acetaldehyde↗
PubMed1999

Morphologic characteristics of initial lymphatics of the healthy and diseased human gingiva.

Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium.

Gingiva↗
PubMed1998

Inhibition of prostanoid synthesis protects against neuronal damage induced by focal ischemia in rat brain.

Changes in prostanoids concentration and effects of the non-specific COX inhibitor indomethacin on prostanoids levels and extension of tissue damage were studied following focal ischemia induction in the fronto-parietal region of rat brain. Ischemia was induced in animals bearing a transcerebral microdialysis probe by injection of Rose Bengal, a photosensitive dye, followed by light activation. Prostanoid levels were determined in the dialysate using immunoenzymatic techniques. PGD2 levels rose significantly up to 237+/-22 pg/ml compared to a basal level measured before ischemia induction which was below the detection limit. TXB2 changes were smaller and had a different time course. Treatment with indomethacin abolished the ischemia-induced PGD2 release and reduced the extent of injury to the area by 43+/-3.7%. These results suggest that prostanoid release may play an important role in neurodegenerative processes and that cyclooxygenase inhibitors may contribute to protect against cerebral tissue damage.

Animals↗
PubMed1997

Localization of beta-D-galactosidase activity in semithin epon sections of embryonic tissues using differential interference contrast optics.

In the present study we describe a method for the histochemical demonstration of beta-D-galactosidase activity on tissue sections processed for light microscopy at high resolution. 5-Bromo-indolyl-beta-D-galactopyranoside (Bluo-Gal) was utilized as an indigogenic method for the demonstration of Escherichia coli beta-D-galactosidase reporter gene activity whose expression was studied in a transgenic line where the enzyme, with a nuclear localization signal (nlacZ), is under the transcriptional control of a striated muscle-specific promoter. At the light-microscopic level, by using Differential Interference Contrast (DIC) optics, the reaction product was detected as precipitates in the form of fine birefringent crystals. These were located around and inside the nuclei of beta-gal-expressing cells. This simple method allows an easy and rapid identification of few or even one labeled cell(s) within large microscopic fields (whole embryos) and the labeled cell(s) can be evaluated both morphologically and quantitatively.

Animals↗
PubMed1996

Structure of the initial lymphatics of the human urinary bladder with invasive urothelial tumors.

The ability of urothelial tumors of the urinary bladder to metastasize via the lymphatic circulation and the extent of metastatic involvement of regional lymph nodes is an important parameter in the staging and prognosis of these neoplasms. Accordingly, we examined the site and morphology of initial lymphatic vessels in the mucosa of the human urinary bladder in patients with invasive transitional cell carcinoma. Lymphatics in the papillary tumoral mass was also examined. Endoscopic transurethral biopsies from the urinary bladder of 120 patients with invasive transitional cell papillary carcinoma were utilized for this study. Biopsy from the uninvolved lateral wall of the same patient was utilized as a control. On histopathology of biopsies of neoplastic tissues, initial lymph vessels were seen in the deeper region of the mucosa but not in the subepithelial layer nor in the stroma of the tumoral papillae. The latter were often associated with arteriolar and venular vessels. When edema and inflammation occurred in peritumoral regions, lymphatics showed a dilated lumen, non-indented wall with dissociated perivascular collagen and elastic fibers. Tumoral permeation or embolization of lymphatics was seen in 12% of patients with invasive tumors, and these lymphatic vessels did not display significant morphologic changes. The absence of initial lymphatics in the stroma of tumoral papillae and in infiltrated subepithelial regions of the urinary bladder may explain the absence of lymph node metastasis in early-stage invasive urothelial tumors.

Adult↗
PubMed1995

The lymphatic vessels and their relationship to lymph formation in the human urinary bladder.

After endoscopic transurethral biopsies of normal human urinary bladder, an extensive network of small initial lymphatic vessels was depicted by means of light and electron microscopy. Using light microscopy, lymphatic vessels were seen in the mucosa and submucosa and formed a complex network in the detrusor muscular coat. These lymphatics were characterized by an irregular and attenuated wall and increased in number and size from the superficial to the deeper region of the bladder. Ultrastructurally, the lymphatic wall was characterized by endothelial cells joined together end-to-end or by complicated interdigitations. Often intercellular channels and gaps between two contiguous endothelial cells were present. A broad network of elastic and collagen fibers joined the lymphatic endothelial wall to the neighboring connective tissue. Nevertheless, as far as the fibrillar component was concerned, the vesical intramuscular lymphatic endothelial wall lacked elastic fibers. These anatomic variations were examined in reference to lymph formation in an organ (the urinary bladder) which undergoes continual changes in volume and pressure.

Adult↗
PubMed1995

Ultrastructural Localization of elastin-like immunoreactivity in the extracellular matrix around human small lymphatic vessels.

The distribution of elastin-like immunoreactivity around small lymphatic vessels was investigated in three different human tissues (skin, heart and dental pulp) using high resolution immunocytochemistry. Quantitative assessment of the immunogold reaction was performed with an image analysis system. Intense and moderate elastin-immuno-reactivity was detected in the extracellular matrix around small lymphatic vessels of the skin and heart, respectively. By contrast, absence of immunostaining was observed around lymphatic vessels in the dental pulp. Although the staining was mostly detectable on the non-fibrillar amorphous component of the extracellular matrix, some microfibrils were also immunostained in close proximity to the lymphatic vessel wall. These findings support the concept that small lymphatic vessels may be heterogeneous with respect to the composition of the extracellular matrix around their wall. The observation that it is possible to observe small lymphatic vessels displaying low or no elastin-immunoreactivity in the adjoining matrix militates against the hypothesis that elastic fibers play a pivotal role in the mechanisms that regulate the function of small lymphatic vessels.

Elastin↗
PubMed1994

Lymphatic capillaries of the pig lung: TEM and SEM observations.

Pulmonary lymphatic vessels extend within the connective tissue sheets surrounding airways and blood vessels. Frequently in this location they also border the lobular parenchyma, but not lymphatic vessels have been found within intralobular compartments between blood capillaries and alveoli. The presence and distribution of lymphatic vessels in pulmonary tissue are consistent with an important role for the lymphatic system in the clearance of interstitial fluids in the lung. Pulmonary lymphatic channels have structural characteristics of initial lymphatics; their walls are formed only by an endothelial layer, and no muscular cells are present. A network of anchoring filaments and collagen and elastic fibers surrounds the vessel walls. Because the lung is a mobile organ the tissue undergoes compression and distension during respiratory phases. These modifications could have a role in the mechanisms for lymph formation and flow.

Animals↗
PubMed1994

Morphological changes of dermal blood and lymphatic vessels in chronic venous insufficiency of the leg.

Morphological changes of dermal blood and lymphatic microcirculation in skin biopsies from patients affected by Chronic Venous Insufficiency (CVI) associated with stasis dermatitis of the lower limbs, are reported here. Blood vessels are characterized by an occluded lumen, thickening and reduplication of the basement membrane. The structural changes in dermal lymphatic vessels are: (i) collapsed lumen of lymphatics located in the papillar dermis; (ii) numerous and complex interdigitations between contiguous endothelial cells and lack of open junctions; (iii) derangement of the anchoring filaments that normally pull the lymphatic lumen open. The connective matrix is characterized by fibrosis with formation of dense bundles of collagen and elastic fibers. These results suggest that the dermal lymphatic and blood microcirculation in CVI are connected to a reduced fluid exchange capacity because of the structural changes occurred in the vascular and lymphatic wall and in the surrounding connective tissue.

Biopsy↗