Biomedical subjects

A Sannino

Publications and source records attributed to A Sannino.

At least 19 recordsLinked to original sources

PubMed2006

Synthesis and characterization of macroporous poly(ethylene glycol)-based hydrogels for tissue engineering application.

Peptide activated poly(ethylene glycol) (PEG)-based hydrogels have received wide attention as material for tissue engineering application. However, the close structure of these materials may pose severe barriers to tissue invasion and nutrient transport. The aim of this work was to synthesize highly interconnected macroporous PEG hydrogels, suitable for use as tissue engineering scaffolds, by combining the photocrosslinking reaction with a foaming process. In particular, various porous samples, differing for both the polymer molecular weight and concentration in the starting precursor solution, have been prepared and characterized by means of scanning electron microscopy and mercury porosimetry. Moreover, water swelling properties have been evaluated and compared with those of the conventional nonporous ones, by performing both equilibrium and kinetic swelling measurements in distilled water. Results indicated that foamed hydrogels display a well-interconnected porous network, suitable for tissue invasion and free molecular trafficking within them. Pores dimension as well as swelling rate can be modulated by polymer concentrations and bubbling agent composition in the precursor solution.

Biocompatible Materials↗

PubMed2006

Hyaluronic acid based materials for intestine tissue engineering: a morphological and biochemical study of cell-material interaction.

A wide number of gastro-intestinal disorders are associated with structural alterations of this district leading to an impaired gastrointestinal function. The study of cell material interactions represents one of the major issues for the development of tissue engineering purposes. Benzyl esters of hyaluronic acid are promising materials because they exhibit good tissue compatibility and are available in various configurations. In this work they have been studied for the possible application of intestinal cell growth and functioning. The preliminary investigation on the morphologic and biochemistry data obtained by monitoring the growth and differentiation of intestinal epithelial cells on two hyaluronic acid benzyl esters is reported. Two types of materials structures were studied: a three dimensional matrix and a macroporous flat sheet membrane. Caco-2 cell line was used: these cells undergo spontaneous enterocytic differentiation after several days in culture. The differentiation status of these cells grown on different materials was used as a parameter of biocompatibility and cell functioning. The status of cell growth and differentiation was monitored by studying cell morphology using scanning electron microscopy. The results obtained were confirmed by biochemical determinations. Although both the configurations of the two polymers exhibited good compatibility with respect to intestinal cells, only the flat sheet membrane proved to induce cell differentiation, leading us to the conclusion that it is a promising substrate for the proposed application.

Biocompatible Materials↗

PubMed2005

Polymeric meshes for internal sutures with differentiated adhesion on the two sides.

The aim of this work is to investigate the effects of different plasma treatments on ePTFE abdominal prostheses with the final goal of obtaining a new prosthesis, made of a single strand of ePTFE, with clearly differentiated adhesion properties on the two sides, which should be able to promote tissue ingrowth on one side and prevent post surgical visceral adhesions on the other. Samples obtained from ePTFE Bard Dulex Meshes have been treated sequentially with three different gases (N(2), O(2) and NH(3)) in order to choose the optimal treatment conditions to improve ePTFE wettability. In particular, no modification was induced by N(2) treatment, while the full treatment after the final ammonia gas resulted in the best suitable candidate. As demonstrated by scanning electron microscopy, AFM analyses and contact angle measurements, ammonia plasma treatment increases ePTFE surface roughness and renders it more hydrophilic, thus promoting adhesion without any alteration of the material's bulk properties. The reported results also evidence the possibility to obtain the maximum wettability with a cheap treatment by optimizing plasma exposure time. As a preliminary cell adhesion study, Swiss 3T3 fibroblasts (mouse, embryo) have been seeded on the treated and untreated materials in order to assess whether there was any difference in terms of cell attachment and spreading. Cells seeded on the ammonia plasma treated material showed a better adhesion and spreading when compared to the untreated material.

Adhesiveness↗

PubMed2003

Biomedical application of a superabsorbent hydrogel for body water elimination in the treatment of edemas.

A novel system of body water elimination to be used for the treatment of edemas, based on superabsorbent cellulose derivatives able to absorb large amounts of water and water solutions, has been investigated. Hydrogels have been synthesized starting from water solutions of carboxymethylcellulose sodium salt and hydroxyethylcellulose, chemically crosslinked with divinylsulphone. Polyelectrolyte hydrogels displayed high sensitivity in sorption capacity to variations of the ionic strength and pH of the external solution, which is a key parameter for the application under investigation. Further, swelling properties have been modulated acting on the degree of crosslinking of the macromolecular network, and a direct method for the measurement of this parameter based on NMR solid-state analysis has been provided. The hydrogel biocompatibility has been studied in terms of its capacity either to induce nitric oxide and lactate dehydrogenase release by macrophages or influence their viability. The eventual release of toxic substances from the hydrogel was also investigated using Swiss 3T3 fibroblasts. The results obtained from the biocompatibility studies carried out in this work are consistent with the hypothesis that this gel may represent an alternative to diuretic therapies in those pathologic conditions in which edemas occur.

Absorption↗

PubMed2003

Lack of genotoxic effects (micronucleus induction) in human lymphocytes exposed in vitro to 900 MHz electromagnetic fields.

In the present study, we investigated the induction of genotoxic effects in human peripheral blood lymphocytes after exposure to electromagnetic fields used in mobile communication systems (frequency 900 MHz). For this purpose, the incidence of micronuclei was evaluated by applying the cytokinesis-block micronucleus assay. Cytotoxicity was also investigated using the cytokinesis-block proliferation index. The experiments were performed on peripheral blood from 20 healthy donors, and several conditions were tested by varying the duration of exposure, the specific absorption rate (SAR), and the signal [continuous-wave (CW) or GSM (Global System of Mobile Communication) modulated signal]. The following exposures were carried out: (1) CW intermittent exposure (SAR = 1.6 W/kg) for 6 min followed by a 3-h pause (14 on/off cycles); (2) GSM signal, intermittent exposure as described in (1); (3) GSM signal, intermittent exposure as described in (1) 24 h before stimulation with phytohemagglutinin (8 on/off cycles); (4) GSM signal, intermittent exposure (SAR = 0.2 W/kg) 1 h per day for 3 days. The SARs were estimated numerically. No statistically significant differences were detected in any case in terms of either micronucleus frequency or cell cycle kinetics.

Adult↗

PubMed2000

Cellulose-based hydrogels as body water retainers.

In this work the possibility of using hydrogels as body water retainers for a therapeutic aid in pathologies such as oedemas of various origins was explored. For such a purpose, the material requires a good compatibility and a controlled swelling capacity without altering the body electrolyte homeostasis. The hydrogel was designed to meet the swelling requirements with the physiological constraints and its biocompatibility was assessed either in vitro or in vivo. Absorption tests were performed in order to define the swelling behavior by varying the pH and ion content of the external solution. The hydrogel swelling capacity was assessed in the presence of various solvents, in order to evaluate its absorption capacity in solutions similar to biological fluids. In addition, the capacity of the gel to modify electrolyte homeostasis by adsorbing ions such as calcium, potassium and sodium was tested. In order to assess the gel biocompatibility after contact of the hydrogel with intestinal cells, arachidonic acid relase was determined. No significant intracellular increase of free arachidonic acid was found in the cells after up to 2 h of contact with the gel. The results suggest that, as far as brief periods are concerned, the gel does not cause an inflammatory response in intestinal cells.

Journal Article↗

PubMed1993

[ST elevation during ergometric test: correlation with coronary angiography].

BACKGROUND: ST elevation during ergometric stress test (EST) is relatively rare. Its prevalence depends upon the tested population but occurs more frequently in patients who have had myocardial infarction or variant angina. This phenomenon is very rare in patients with typical exertional angina and its pathogenesis is still unclear. MATERIAL AND METHODS: We studied a group of 75 consecutive patients with exertional angina who underwent EST and coronary angiography. A symptom limited EST was performed in the upright position on a cycloergometer with load increases of 25 watts every 3 minutes and 12 leads were monitored during all test. Coronary angiography was performed according to Judkins technique. From these patients, according to Froelicher's criteria, a group of 49 patients (age 32-68, mean 51.6 years), without myocardial infarction and/or left ventricular asynergy, was selected. RESULTS: All patients had a coronary artery disease (16 patients with 3 vessels, 11 patients with 2 vessels and 22 patients with 1 vessel disease). The EST was positive for ST depression in 31 patients (63.3%) and for ST elevation in 5 patients (10.1%), while 13 patients (26.6%) had a non diagnostic EST. The ST elevation occurs in V1-V2 and it was associated in all cases with a stenosis in the left anterior descending (LAD) artery. Therefore we divided the 19 patients with LAD stenosis into two subgroups: subgroups A (9 patients, mean age 49.6 years) with LAD stenosis > or = 90% and subgroups B with LAD stenosis between 70% and 90%. ST elevation occurs in 5 patients (55.5%) of subgroup A and in no patient of the subgroup B. Moreover, in the subgroup A ST elevation seems to be related to the anatomic localization of the stenosis: in fact it appears in 83.3% of patients with LAD stenosis located before the onset of the first diagonal branch. CONCLUSIONS: From these data it can be desumed that ST elevation in V1-V2 that occurs in patients with exertional angina and without myocardial infarction or variant angina is strongly predictive of a very important LAD stenosis.

Adult↗

PubMed1992

[Mid-term clinical study of the effectiveness of and tolerability to simvastatin ++ in dyslipidemic patients].

The HGM-CoA reductase inhibitors, blaking up intracellular synthesis of cholesterol, support the receptorial captation of cholesterol with a reduction in plasma levels. The simvastatin efficacy was evaluated in 12 patients, mean age 59 +/- 10 years with a primary hypercholesterolemia. All the patients were on a pharmacologic wash out for at least 6 weeks and dietetic treatment (according to their weight and daily needs) for a week. Total cholesterol, HDL-cholesterol and triglycerides plasma levels were taken at time 0. Then a treatment with simvastatin 10 mg/die was begin for 4 weeks and than increased to 20 mg in patients with plasma cholesterol > 200 mg/100 ml at the end of fourth week. In some patients the dose was increased up to 40 mg for the elevated levels of plasma cholesterol at the end of the second month. All the parameters above were controlled monthly for three months. A control was performed at the end of sixth month of treatment. After 4 weeks treatment, simvastatin induced reduction in cholesterol plasma levels (p < 0.005), that continued during the whole time treatment (228 mg/dl at 24 week, p < 0.005 vs basal). The mean dosage of the simvastatin at fourth month was of 25 mg/die. During the treatment an increase of HDL plasma levels was noted, but this increment wasn't statistical significant (40 +/- 7 vs 45 +/- 9 mg/100 ml). No significant impairment of principal metabolic and laboratory parameters were observed during the treatment. These data indicate that simvastatin in small dose induce a reduction in cholesterol plasma levels with a significant increase in HDL without side effects.

Adult↗

PubMed1989

[An association of diabetic bullosis and diabetic neuropathy. A clinical case report].

A case of bullosis diabeticorum, a rare complication of diabetes whose genesis is not yet clear is reported. In the present case, the complication was associated with marked somatic and autonomic neuropathic impairment.

Acute Disease↗

PubMed1983