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Biomedical subjects

F Forni

Publications and source records attributed to F Forni.

At least 19 recordsLinked to original sources
PubMed2003

Ten-year follow-up in a maxillary sinus augmentation using anorganic bovine bone (Bio-Oss). A case report with histomorphometric evaluation.

Several bone grafting materials have been used in sinus augmentation procedures. Bio-Oss (deproteinized and sterilized bovine bone) has shown to have osteoconductive properties and no inflammatory or adverse responses have been published. In spite of these successful results, histologic data regarding bone augmentation using Bio-Oss in humans is scarce. The purpose of this study was to analyse the amount of Bio-Oss ossification in a case of maxillary sinus augmentation, recording and comparing histomorphometric data 8 months, 2 and 10 years after surgery. This long-term histologic evaluation of retrieved specimens has been performed, comparing histomorfometric measures at different times. Eight months after surgery we observed in 20 different thin sections of the specimen a mean amount of bone tissue (including medullar spaces) of 29.8% (and 70.2% of Bio-Oss) +/- 2.6. At 2 years the bone tissue increased to 69.7% + 2.7 and 10 years after surgery it was 86.7% +/- 2.8. The comparison of the means for each time has shown a highly significant increasing trend in bone formation associated with Bio-oss resorption: at 8 months, 2 and 10 years.

Alveolar Ridge Augmentation↗
PubMed2002

Poly(lactic acid) microspheres for the sustained release of antiischemic agents.

We report a preliminary study evaluating the encapsulation modalities in microparticles of the antiischemic drug N(6)-cyclopentyladenosine (CPA). The effects of release systems have been evaluated on the stability in human whole blood of CPA and its affinity toward human adenosine A(1) receptors. The microspheres were prepared by an emulsion-solvent evaporation method (different CPA amounts and two stirring rates were employed) using poly(lactic acid). Free and encapsulated CPA was incubated in human blood and the drug stability was analyzed. The affinity of CPA to human A(1) receptor was also obtained in the presence and in the absence of unloaded microspheres. The microspheres obtained using 1200 rpm showed a broad size distribution and a mean diameter value of 21+/-9 microm. Using 1700 rpm the mean diameter decreased to 5+/-2 microm and a more homogeneous size distribution was obtained. The CPA release changed with the particle size and the different amounts of drug employed during the preparation of the microspheres. The degradation in human whole blood of CPA encapsulated in the microspheres was negligible, with respect to that of free CPA. Affinity values of CPA obtained in the absence and in the presence of unloaded microspheres were the same.

Adenosine↗
PubMed2001

Poly(lactic acid) microspheres for the sustained release of a selective A1 receptor agonist.

A study concerning the feasibility of microsphere use as sustained delivery systems for N(6)-cyclopentyladenosine (CPA) administration has been performed. The release of this drug and the related stability effects in human whole blood have been tested. Moreover, the impact of the delivery system on CPA interaction toward human adenosine A1 receptor and the related cellular responses has been analyzed. The microspheres were prepared by an emulsion-solvent evaporation method using poly(lactic acid). Free and encapsulated CPA was incubated in fresh blood and the drug stability was analyzed with HPLC. The affinity of CPA to human A1 receptor expressed by CHO cells was obtained by binding experiments. Activity was evaluated by measurements of the inhibition of forskolin-stimulated 3',5'-cyclic adenosine monophosphate (c-AMP) performing competitive binding assays. Encapsulated CPA was released within 72 h and its degradation in blood was negligible. Affinity and activity values of CPA obtained in the absence and in the presence of unloaded microspheres were the same. CPA encapsulation in microspheres allows its sustained release and its stabilization in human whole blood to be obtained. The presence of this release system does not interfere with the CPA activity at its action site.

Adenosine↗
PubMed2001

Gelatin microspheres crosslinked with D,L-glyceraldehyde as a potential drug delivery system: preparation, characterisation, in vitro and in vivo studies.

To overcome the restriction in using crosslinked gelatin in the pharmaceutical field, D,L-glyceraldehyde (GAL), a non-toxic crosslinking agent, was proposed. Gelatin microspheres crosslinked with different concentrations of GAL (0.5, 1 or 2%, w/v) and for different time periods (1 or 24 h) were prepared. The effect of the preparation variables was evaluated analysing the extent of crosslinking, the morphological aspect, the particle size and the swelling behaviour. To evaluate the pharmaceutical properties, an antihypertensive drug, clonidine hydrochloride, was chosen as drug model and loaded into the microspheres. Either the increase of the crosslinker concentration or of the crosslinking time period decreased both the swelling and the in vitro drug release processes of the microspheres. After the subcutaneous injection, the loaded microspheres crosslinked with the lowest GAL concentration (0.5%, w/v) or for the shortest time period (1 h) showed a reduction of systolic blood pressure (SBP) similar to that recorded with a clonidine hydrochloride solution having the same drug concentration. Instead, the microspheres crosslinked for 24 h with concentrations of GAL higher than 0.5% (w/v) produced a more gradual and sustained SBP reduction and the antihypertensive effect was maintained until 52-72 h. The biocompatibility studies showed that the microspheres crosslinked with GAL are well tolerated in vivo. These results suggest the potential application of gelatin microspheres crosslinked with GAL as a suitable drug delivery system for the subcutaneous administration.

Animals↗
PubMed2000

Effect of matrix composition and process conditions on casein-gelatin beads floating properties.

Casein-gelatin beads have been prepared by emulsification extraction method and cross-linked with D,L-glyceraldehyde in an acetone-water mixture 3:1 (v/v). Casein emulsifying properties cause air bubble incorporation and the formation of large holes in the beads. The high porosity of the matrix influences the bead properties such as drug loading, drug release and floatation. These effects have been stressed by comparison with low porous beads, artificially prepared without cavities. The percentage of casein in the matrix increases the drug loading of both low and high porous matrices, although the loading of high porous matrices is lower than that of low porous matrices. As a matter of fact, the drug should be more easily removed during washing and recovery because of the higher superficial pore area of the beads. This can explain the drug release rate increase, observed in high porous matrix, in comparison with beads without cavities. This is due to the rapid diffusion of the drug through water filled pores. The study shows that cavities act as an air reservoir and enable beads to float. Therefore, casein seems to be a material suitable to the inexpensive formation of an air reservoir for floating systems.

Caseins↗
PubMed2000

Surface drug removal from ibuprofen-loaded PLA microspheres.

The preparation, characterisation and drug release behaviour of ibuprofen loaded poly(D,L-lactic acid) (PLA) microspheres are described. Depending on the gelatin concentration in the aqueous external solution (1, 0.5, 0.1% w/v), microspheres with three different sizes (2.2, 4.1, 7.5 micrometer) were obtained. The properties of microspheres washed with water (Untreated microspheres) (Un-Ms) were compared to those of the microspheres washed with a sodium carbonate solution in order to remove the surface drug (treated microspheres) (T-Ms). The results indicate that the removal of the surface drug did not induce any change in the size of the microspheres whereas the morphology of the smallest T-Ms appeared to be modified. The release profiles of both Un-Ms and T-Ms resulted in biphasic patterns. The initial burst effect (first release phase) of the T-Ms was lower than that of the Un-Ms. The rate of the second release phase did not change for the microspheres with the biggest size but increased for the smallest microspheres probably owing to the modification of the matrix porosity.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Casein/gelatin beads: I. Cross-linker solution composition effect on cross-linking degree.

The effect of the cross-linker solution composition (aqueous and organic ratio) on the cross-linking degree of hydrophilic casein/gelatin beads has been evaluated. Casein/gelatin beads with different radii have been prepared and treated over the same time with three different cross-linker solvent compositions containing d, l-glyceraldehyde at the same concentration. The cross-linking degree was studied not only comparing the results of swelling process and degradation rate, widely reported in literature as methods for the cross-linking degree evaluation, but also determining the solvent penetration rate and the d,l-glyceraldehyde reacting percentage. It has been observed, in fact, that the cross-linker solvent composition influences the penetration rate through the matrix of the cross-linker, thus controlling the homogeneity of the matrix cross-linking.

Caseins↗
PubMed1999

Dynamic dialysis for the drug release evaluation from doxorubicin-gelatin nanoparticle conjugates.

The drug release from doxorubicin (DXR)-gelatin nanoparticle conjugates was evaluated by means of a dynamic dialysis technique. The study was carried out in absence and in presence of a proteolytic enzyme (trypsin) able to degrade the carrier. In a preliminary study the apparent permeability constant (Kcv) of the drug through the dialysis bag was evaluated in several media. On the basis of this screening, a saline solution (NaCl 0.9%, w/v) resulted appropriate to carry out the dialysis study since, in this medium, the Kcv did not depend on the drug concentration in the donor solution. In absence of the enzyme only a little fraction (from 9 to 13%, w/w of the drug content) was released from nanoparticles. This fraction was considered as the evidence of the free drug fraction. After the addition of trypsin, the diffusion of a further drug fraction was observed. This fraction is probably due to a fraction of the DXR-peptide conjugates characterised by a molecular weight lower than membrane cut-off (3500 Da).

Animals↗
PubMed1999

Synthesis and characterisation of poly(D,L-lactic acid)-idoxuridine conjugate.

A new polymeric prodrug was prepared coupling 5-iodo-2'-deoxyuridine (IDU) to poly(d,l-lactic acid) (PLA) via a succinic acid spacer. The PLA-IDU conjugate was characterised by thermal analysis, IR and 1H and 13C NMR spectroscopy. The IDU content (0.024 mequiv.g-1 of PLA) was consistent with the carboxylic acid endgroup present in the polymer sample (0.025 mequiv.g-1 of polymer). The PLA-IDU conjugate was susceptible to degradation in biological environments containing esterase, whereas IDU was not detected by chemical hydrolysis in pH 7.4 phosphate buffer. The conjugate should be used to prepare injectable microspheres and nanospheres containing IDU chemically coupled to the polymer carrier.

Animals↗
PubMed1998

Influence of feeding on metabolite excretion evidenced by urine 1H NMR spectral profiles: a comparison between subjects living in Rome and subjects living at arctic latitudes (Svaldbard).

Urines from 25 normal subjects living in Rome and 25 normal subjects living in Ny-Alesund (Svaldbard) were analysed by 1HNMR spectroscopy. The observed differences in the concentration of the major metabolites were correlated to the composition of the diet. It was found that a diet rich of carbohydrates, such as the Italian diet, is responsible for an increased excretion of citrate, lactate, alanine, and glycine. Thus, a correct diagnostical interpretation of urinary metabolites needs to consider feeding habits.

Adult↗
PubMed1998

Proton nuclear magnetic resonance spectral profiles of urine in type II diabetic patients.

Serial urine samples of 33 type II diabetic patients and 20 control subjects were examined by 1H nuclear magnetic resonance (NMR). Metabolites including lactate, citrate, glycine, alanine, hippurate, trimethylamine-N-oxide, and dimethylamine were identified in all subjects although in higher concentrations in diabetic patients. Other analytes, such as creatine, acetate, betaine, and ketone bodies, were found more frequently and in greater concentrations in diabetics than in controls. In addition, although lactate, citrate, alanine, and hippurate concentrations increased with increasing glycosuria and glycohemoglobin, trimethylamine-N-oxide and dimethylamine were present at high concentrations even in diabetics with good metabolic control. 1H NMR spectroscopy permitted us to explore the relationships among the metabolites present in the urine samples and to obtain information about the disease status in type II diabetic patients.

Aged↗
PubMed1997

1H NMR spectra of normal urines: reference ranges of the major metabolites.

Serial urine samples from 50 normal subjects were studied by 1H NMR spectroscopy operating at 300 MHz. Analyses of the spectra have shown the presence of the following metabolites in 100% of the normal subjects: Creatinine, lactate, alanine, citrate, dimethylamine, trimethylamine-N-oxide, glycine and hippurate. Other analytes, such as creatine, valine, betaine, leucine and isoleucine, were sometimes found. All metabolites were quantified on the basis of peak heights and were expressed as mmol/mol of creatinine. The study of metabolic profiles in serial samples allowed us to evaluate intra-individual variability and physiological changes due to feeding. The aim of our report is to define standard conditions for this analytical technique and to calculate confidence intervals for the major metabolites in normal urine samples, such as preliminary and mandatory stages for clinical diagnostic 1H NMR utilization.

Adult↗
PubMed1993

Enzymatic determinations in acute rejection after liver transplantation: preliminary report on necrosis index.

The catalytic activities of some mitochondrial and cytoplasmic enzymes were measured in plasma from 19 patients after orthotopic liver transplantation, in order to detect and monitor the evolution of hepatocellular damage and to predict liver rejection. The enzymatic activities determined were: mitochondrial isoenzyme of aspartate aminotransferase, glutamate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltranspeptidase and alkaline phosphatase. The results of all enzymatic activities were normalized by expressing them as multiples of the upper limit of the relevant reference range and then the necrosis index (NI) has been calculated. The proposed NI consists of percent ratio of the normalized mitochondrial enzymatic activities over the sum of cytoplasmic and mitochondrial normalized activities. We observed that NI values higher than 30% correctly identified all but two acute rejection events which were documented by liver biopsies showing a diagnostic sensitivity of 90%, specificity of 78% and a predictive value of 90%.

Adult↗
PubMed1991

The effect of the cross-linking time period upon the drug release and the dynamic swelling of gelatin microspheres.

The cross-linking time period affected both the swelling and release processes of cross-linked gelatin microspheres. In the dynamic swelling procedure, the combination of both phenomena of microparticle swelling and drug diffusion produced at first the increase and then the decrease of the diameter of a loaded microsphere. The increase of the cross-linking time period produced the shift of the penetrant transport from anomalous to super-case II kinetics. This behaviour could justify the decrease of the diffusion component of the drug release as the cross-linking time period increased.

Aminophylline↗
PubMed1990

Oxidative stress of red blood cells stored for transfusion use.

Some oxidative indexes and the level of reduced glutathione have been determined on red blood cells stored for transfusion use. Conjugated dienes show a concentration which increases until around the third week of storage and then comes back to lower values. On the contrary malonyldialdeyde shows a decreasing level until the third week and then rises rapidly to very high values. Reduced glutathione rises until about the end of the second week and then falls to very low values. Free haemoglobin continuously rises through the whole period of storage; from these data it is evident that a storage time not exceeding 21 days gives the best transfusion results.

Alkenes↗