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Biomedical subjects

L Montanari

Publications and source records attributed to L Montanari.

At least 37 records · Page 2Linked to original sources
PubMed1999

In vitro skin permeation of Sinitrodil, a member of a new class of nitrovasodilator drugs.

Clinical trials have shown the potential of benzoxazinones, a new class of organic nitrates, in cardiovascular therapy. In particular Sinitrodil possesses a coronary vascular selectivity greater than that of Nitroglycerin and isosorbide dinitrate. The objective of this study was a preliminary evaluation of the ability of these new organic nitrate derivatives to reach therapeutical steady-state plasma concentrations following a transdermal administration. In vitro permeation studies through human stratum corneum and epidermis have been conducted on two members of this class: Sinitrodil (ITF 296) and ITF 1129. Comparative studies have also been carried out with Nitroglycerin, Isosorbide dinitrate and Nicorandil. Two different fixed concentrations were tested: 0.08% w/v solution and saturated solution. Sinitrodil could be considered a good candidate for transdermal administration on the basis of the in vitro permeation results and of the known therapeutical plasma concentration.

Benzoxazines↗
PubMed1999

Evaluation of adhesive properties of patches based on acrylic matrices.

Adhesion is an essential property of the dermal and transdermal therapeutic systems (TS). It is influenced by the composition and the thickness of the matrix and also by the characteristics of the backing layer. Our aim was to evaluate the usefulness of the "thumb tack test," the "tack rolling ball test," and the "peel adhesion 180 degrees test" in the development studies and quality control of TS. These tests were performed on two series of placebo patches in which the backing layer was made of artificial silk (series 1) and polyurethane film (series 2). The patches of both series were prepared using five different mixtures of a hydrophilic adhesive copolymer and a hydrophobic nonadhesive copolymer as matrices. Plastoid E 35 L, a copolymer of dimethylaminoethyl methacrylate and neutral methacrylic esters, was used as the adhesive polymer. Eudragit NE 40 D, a copolymer of ethylacrylate and methylmethacrylate, was used as the nonadhesive copolymer. In the standard procedure for the peel adhesion 180 degrees test, used in the tape industries, the adherent is made of stainless steel. Because the latter has a high surface energy, it was not suitable for the analysis of the patches with a polyurethane backing layer. Therefore, the critical surface tension of five alternative materials (rubber, polysiloxane, polyethylene, nylon, polyvinyl chloride) was evaluated. Polyethylene was selected for the modified peel adhesion 180 degrees test, and better results were obtained in terms of feasibility of the test and ability to discriminate between the different patches prepared.

Acrylates↗
PubMed1999

Dermal patches for the controlled release of miconazole: influence of the drug concentration on the technological characteristics.

The aim of this work was to evaluate the effect of different amounts of miconazole nitrate (MIC) on the technological characteristics (drug release profile, adhesiveness, and water vapor permeability) of a nonocclusive dermal therapeutic system (DTS) for the treatment of tinea unguium infection. Artificial silk was used as a backing layer. The self-adhesive matrix was made of a mixture of Plastoid E 35 L (PL L), an adhesive hydrophilic polymer, and Eudragit NE 40 D (EU NE), a nonadhesive hydrophobic polymer able to modify the drug release. Plastoid E 35 L is a copolymer of dimethylaminoethyl methacrylate and neutral methacrylic ester. Eudragit NE 40 D is a copolymer of ethylacrylate and methylmethacrylate. Formulations containing different amounts of MIC, ranging from 2% to 16% w/w of the dried matrix, were designed. Drug crystals were observed by polarizing light microscopy, proving the incomplete solubilization of MIC only in the matrices containing 8% w/w or more of this compound. All systems provided an in vitro control of drug release for at least 24 hr. The amount of the drug released increased with drug loading in all DTS. The percentage of the drug released was the same in all the DTS containing detectable crystals of MIC. When the MIC was completely dissolved in the matrix, the released percentage decreased when drug loading increased. The water vapor permeability and the adhesive properties of the DTS were excellent.

Administration, Cutaneous↗
PubMed1999

Comparison of different membranes with cultures of keratinocytes from man for percutaneous absorption of nitroglycerine.

The permeability barrier function of cell-culture membranes to the permeation of nitroglycerine was evaluated to find an alternative to skin from man for ex-vivo skin-permeation tests. The membranes were prepared, under submerged conditions, by inducing the growth of keratinocytes, from different donors, on a film of esterified jaluronic acid for different times (10, 20 and 30 days). Their permeability barrier functions were compared with those of some of the most widely used artificial membranes, silicone rubber (Silastic), cellulosic material (Cuprophan, Millipore HAWP), polysulphone membrane (Supor) and polytetrafluoroethylene membrane (TF-PTFE), and with those of biological membranes such as fresh and frozen skin, stratum corneum and epidermis from man, and hairless mouse skin. For each membrane the permeation profile was obtained and the flux was calculated. The permeation profiles for nitroglycerine were similar and linear in the first 2-3 h for all the synthetic membranes tested except TF-PTFE. For this membrane the profile was linear throughout the period considered and the amount permeating in 24 h (1603 microg cm(-2)) was significantly lower than those obtained for the other artificial membranes (between 1926 and 2508 microg cm(-2)). The amounts permeating through all the biological membranes in 24 h were in the range 520 to 781 microg cm(-2), except those for the keratinocyte-culture membranes, which were in the range 1730 to 2553 microg cm(-2). Prolonging the growth period of cultured keratinocytes did not affect nitroglycerine permeation. The findings suggest that these keratinocyte-culture membranes have some advantages--good reproducibility if obtained from the same donor; many membranes can be obtained from the same donor; the preparation is simple; they can be handled more easily than traditional cell-culture membranes; and they afford constant penetration rates for a longer period than synthetic membranes. The membranes could be used for preliminary in-vitro permeation studies.

Animals↗
PubMed1999

[Transvaginal ultrasonic evaluation of the thickness of the section of the uterine wall in previous cesarean sections].

BACKGROUND: The aim of this study is to evaluate accuracy of transvaginal sonographic examination of the lower uterine segment in pregnant women with previous cesarean section. METHODS: Sixty-one pregnant women between 37 and 40 weeks of gestation, with previous cesarean section underwent transvaginal ultrasonography. Wall thickness of the lower uterine segment, the length of cervix, dilation of the isthmus uteri were measured. On the basis of the surgical findings (in 53 patients) and outcome of the trial of labor (in 8 patients) a Score was assigned to the pregnant women: Score 1 to the women who had good healing or a trial of labor without complications; Score 2 to the women with a thin or discontinued scar and in case of threatened rupture of the uterus in the trial of labor. RESULTS: The mean thickness of the lower uterine segment is 3.82 mm +/- 0.99 mm. The Score 1 group shows a mean thickness of 4.2 mm +/- 2.5 mm, and the Score 2 group a mean thickness of 2.8 mm +/- 1.06 mm. The transvaginal sonographic examination provides a sensitivity and a specificity respectively of 100 and 75%, for a thickness cut-off of 3.5 mm, and a positive and negative predictive values of 60.7% and 100% respectively. CONCLUSIONS: The transvaginal sonographic evaluation of the lower uterine segment improves therefore the obstetrical decision-making regarding the trial of labor in women with previous cesarean section.

Adult↗
PubMed1998

Gamma irradiation effects on poly(DL-lactictide-co-glycolide) microspheres.

Gamma radiation treatment plays an increasingly important role in the sterilization/sanitization of pharmaceutical products. However, irradiation may affect the stability of the product and thus its safety of use. We investigated the influence of ionizing radiation on modified release microparticulate drug delivery systems made of two types of polylactide-co-glycolide copolymers (PLG): RG 503 and RG 503H; these polymers have identical molecular weights but different chemical structures. The effect of gamma radiation on polymer stability of the raw polymers (P) and related microspheres (Ms) was evaluated. Samples were irradiated at different irradiation doses (5, 15 and 25 kGy) using 60Co as radiation source. The microspheres were prepared using the spray drying technique. Degradation of PLG and related microspheres was evaluated during six months in terms of average molecular weight (Mw) loss by gel permeation chromatography (GPC) and variation in glass transition temperature (Tg) using differential calorimetry (DSC). The presence of free radicals in the product was tested by electron paramagnetic resonance (EPR). Both P and Ms showed a trend in decreasing their Mw at time 0 as a function of irradiation dose. For RG503 the decay in Mw is always negligible for doses below 15 kGy while it is about 10% for 25 kGy. After 150 days Mw decay was 25% in the microspheres and 20% in the raw polymer. It was not possible to evaluate the radiation effect, at different storage times, for RG503H because this polymer resulted to be unstable even in the regular storage conditions without being irradiated. The concentration of radiation-induced free radicals was higher in RG 503H (both P and Ms) and they were more stable than the free radicals species observed in the case of polymer RG 503. Alterations and/or production of new radicals were observed on exposure of RG 503H microspheres to the light. Radiolytic degradation of RG 503 under vacuum is characterized by a prevalence of the chain scission events leading to a decrease of Mw. Some crosslinking can occur mainly in the post irradiation stage through the decay and coupling of the hydrogen abstraction radicals. A hydroperoxydative cycle, whose mechanism is suggested, is generated in the presence of oxygen.

Biocompatible Materials↗
PubMed1998

Beer affects oxidative stress due to ethanol in rats.

The relationship between chronic moderate beer consumption and oxidative stress was studied in rats. Animals were fed three different isocaloric diets for six weeks: a beer-containing diet (30% w/w), an ethanol-supplemented diet (1.1 g/100 g, the same as in the beer diet) and an alcohol-free basal diet. At the end of the feeding period, rats were analyzed for plasma and liver oxidative status. Some livers were isolated and exposed to ischemia-reperfusion to assess the additional oxidative stress determined by reperfusion. No significant differences in plasma antioxidant status were found among the three dietary groups. Lipoproteins from the beer group, however, showed a greater propensity to resist lipid peroxidation. Ischemia caused a decrease in liver energy and antioxidant status in all groups. Nevertheless, ATP was lower in the livers of rats exposed to the ethanol diet. During reperfusion, lipoperoxidation increased significantly in all groups. However, livers obtained from ethanol-treated rats showed the higher formation of lipoperoxides. In conclusion, a moderate consumption of beer in a well-balanced diet did not appear to cause oxidative stress in rats; moreover, probably through its minor components, beer could attenuate the oxidative action of ethanol by itself.

Adenosine Triphosphate↗
PubMed1997

Presentation and distribution of medicinal products after the new E.U. marketing procedures.

In this paper the new procedures for the marketing authorisation are considered from the point of the view of their influence on the medicinal product presentation (labelling and package leaflet), dispensing and distribution. The legal status of some active ingredients in different countries as well as the situation in the Italian domestic market have been analysed. Even if the European directive is completely implemented, the harmonisation process appears difficult in consideration of the different social, political and economical characteristics of the different countries, and is going to cover many years.

Drug Labeling↗
PubMed1997

Evaluation of the cost of home care for terminally ill cancer patients.

The aim of this work was to carry out a cost evaluation of the home care programme for terminally ill cancer patients run by the Istituto Oncologico Romagnolo (I.O.R.) in the areas of Forlì, Cesena, Ravenna and Rimini (Romagna, Italy). To determine effective home care direct costs, we first selected 1 week of care as an observation unit. We then proceeded to assess the medical and nursing care units together with the clinical protocols administered for each patient. The Karnofsky Performance Status (KPS) was also assessed weekly. In this way, we calculated care costs for each patient and for each week as the sum of medical costs, nursing costs, treatment costs and other costs. A consecutive series of 574 patients were involved in the study from 1 April 1994 to 31 March 1995. A total of 5164 patient-weeks of care was provided, with an average cost per week of 177.6 Ecu. This weekly cost increased in the last 100 days of life (week -15 = 179.5 Ecu; week -8 = 188.3 Ecu; week -2 = 221.0 Ecu; P < 0.001). When single components were analysed in relation to total cost (treatment protocols, physician and nursing care) the increased global cost was found to be mainly attributable to the intensification in nursing care (21.8% of costs in week -15 vs 27.3% of costs in week -2). Examination of the relation between the cost of 1 week of care and KPS values clearly shows that healthcare costs increased as KPS decreased (from 152.2 Ecu with KPS > or = 60 to 292.6 Ecu with KPS < or = 20; P < 0.001). Home care costs were also seen to vary with some clinical characteristics and symptoms present when patients entered the study: asthenia, anorexia, nausea/vomiting, bedsores. Given the good results of home care for cancer patients in terms of quality of life, this method of cost accounting for home-care providers can help to monitor the rising cost of assistance and confirm the cost effectiveness of this type of care.

Adolescent↗
PubMed1996

Mineral evolution of bone.

A study on the evolution with age of the mineral composition of bones was performed on samples belonging to human and other common mammalian species (cattle, sheep, dog). The study was carried out on the ashes obtained by calcination of the bone samples (1 h at 900 degrees C). The calcined powders were carefully examined by X-ray diffraction, from which precise quantitative evaluation (also confirmed by chemical analysis) of the crystalline phases present was derived. These data were analysed as a function of the introduced fractional age phi, a new relative scale that allows even largely different lifespan species to be compared. An overall linear increase in (Ca + Mg)/P ratio with log phi was found and the other considerations on molecular constitution (especially as regards Mg2+ substituting for Ca2+ in very young subjects) of the various phases detected were formulated and relative implications evaluated. The results appear promising for an improvement of knowledge in the field of biomedical experimentation and clinical implantology.

Absorptiometry, Photon↗
PubMed1994

Precocious signs of polycystic ovaries in obese girls.

As several studies have reported that 35% of patients with polycystic ovary syndrome are obese and that this syndrome seems to originate during the early phase of sexual maturation, we undertook a study of such subjects. We studied ultrasound and hormonal findings in 49 obese girls aged from 7.9 to 19.10 years, with a mean excess weight of 44%; 23 premenarcheal girls and 26 postmenarcheal girls with mean gynecological age of 2.5 years. As controls, we studied 18 girls in the pubertal phase and 17 healthy girls with regular menses, matched for age and gynecological age. Pelvic ultrasonography was carried out in all girls and estrone, estradiol, progesterone, prolactin, follicle stimulating hormone, luteinizing hormone, sex hormone binding globulin (SHBG), testosterone, free testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), androstenedione and 17-hydroxyprogesterone (17-OHP) were measured by radioimmunoassay in 11 of the 18 postmenarcheal girls. Five girls (10.2%) with excess weight of > 40% presented with mild or severe hirsutism based on Ferriman and Gallway scores; six (12.2%) presented with acne and 14 (28.5%) presented with acanthosis nigricans.Hormonal evaluation showed elevated levels of estrone (p < 0.005) and testosterone (p < 0.01) but lower than normal levels of SHBG (p < 0.05) and estradiol (p <0.05). On the basis of our results, 23%) of the postmenarcheal obese subjects showed clinical, hormonal and ultrasonographic signs of polycystic ovaries, and 23% of postmenarcheal obese girls showed multifollicular ovaries. Six of these, at 1 year after menarche, showed a uterine cross-sectional area larger than normal for gynecological age (21.92 +/- 5.64 cm(2) vs. 16.36 +/- 2.34 cm(2)). Further serial echographic studies and a careful follow-up will demonstrate if both multifollicular ovaries and increased uterine cross-sectional area in obese girls are precocious signs of polycystic ovaries.

Journal Article↗
PubMed1992

Differences in blood pressure regulation of congestive heart failure, before and after treatment, correlate with changes in the circulating pattern of atrial natriuretic peptide.

The mechanisms underlying altered BP regulation in congestive heart failure are unknown. This study examines the possibility that differences in circadian blood pressure (BP) regulation between the normal and the failing heart correlate with changes in the circulating pattern of atrial natriuretic peptide (ANP). Twelve normotensive patients with coronary artery disease were studied over two separate 24-h periods, the first during acute exacerbation of congestive heart failure (radionuclide-determined ejection fraction at rest was less than 30%) and the second after therapy-induced functional recovery (ejection fraction was more than 40%). BP monitoring at 10-min intervals and intra-atrial blood samples for ANP assays at hourly intervals were obtained. Significant correlation between ejection fraction and the indexes of circadian BP variability (standard deviation of the 24-h pressure mean and day-night pressure difference) were found both before and after treatment. Ejection fraction was independent of the BP means (24-h, daytime and night-time). BP variability, 24-h mean and daytime mean were higher after treatment. ANP means were lower after treatment, whereas ANP variability was higher. The indexes of BP and ANP variability correlated both before and after treatment, whereas the BP and the ANP means were independent. These findings demonstrate that differences in BP regulation of CHF before and after effective treatment correlate with changes in the circulating pattern of ANP. We speculate that by modulating ANP release, the heart could be actively involved in BP regulation as part of the compensatory mechanisms aimed at protecting against circulatory overload.

Aged↗
PubMed1992

Evaluation of hypercholesterol diet-induced changes in viscoelastic properties of carotid circulation in pigs.

Measurements of pulsatile pressure and flow at the input of the left and right carotid arteries and a new lumped parameter model were used to quantify changes in the overall dynamic mechanical properties of the carotid circulation between five control diet-fed pigs and five pigs fed a hyperlipidemic diet for 16 wk. The model represents the portion of the circulation supplied by either the left or the right carotid artery and is characterized by five parameters: peripheral resistance (Rp), an overall inertance (L), and an overall frequency-dependent compliance constituted by a capacitor C (static compliance) in series with a Maxwell section, i.e., a capacitor Cd, in parallel with a resistor Rd. Rp was calculated as the ratio between mean pressure (P) and mean flow (Q). The other four parameters were estimated by fitting measured to model predicted flows. The average static compliance was reduced by 40% (P = 0.01) between normal (P = 62.0 +/- 4.3 mmHg) and hyperlipidemic diet-fed pigs (P = 62.7 +/- 4.7 mmHg). A significant reduction in the overall cross-sectional area was inferred from a 53% increase (P = 0.05) in L, whereas resistance vessel tone was unchanged as judged from estimates of Rp. No signs of occlusive disease were found in any of the animals.

Animals↗
PubMed1992

Loss of nocturnal increase in plasma concentration of atrial natriuretic peptide in hypertensive chronic renal failure.

Diurnal change of plasma atrial natriuretic peptide (ANP) concentration was investigated in 12 patients with hypertension due to chronic renal failure (CRF) and in 12 patients with essential hypertension (EH) of comparable degree. Blood pressure (BP) monitoring was performed at 15-min intervals, while peripheral blood samples were obtained at 4-hour intervals starting from 8.00 h. The mean 24-hour plasma levels (+/- SEM) of ANP were 24.3 +/- 1.8 pmol/l in EH and 23.4 +/- 1.2 pmol/l in CRF. In EH, plasma ANP concentration was highest at 4.00 h (33.5 +/- 0.8 pmol/l) and lowest at 16.00 h (15.5 +/- 0.6 pmol/l). In CRF, no significant circadian change was present (22.2 +/- 3.1 and 20.4 +/- 3.6 pmol/l, respectively), and the nocturnal fall in BP was lost. Our data demonstrate that in CRF the loss and possible reversal of the nocturnal decline in BP is associated with the disappearance of any significant circadian variation in the circulating concentrations of ANP. These findings suggest a role for ANP in the alteration of BP variability of CRF, possibly mediated by autonomic dysfunction, and are further evidence for the existence of a relation between the circadian rhythms of ANP and BP.

Adult↗
PubMed1992

A gas-chromatographic determination of the ppb levels of volatile halogenated hydrocarbons in water for injections.

Some volatile halogenated hydrocarbons have been found in commercial large volume parenterals (LVPs) prepared from untreated or treated (disinfected) water. To monitor the presence of volatile halogenated hydrocarbons in the source water and also in the water for injections, a low cost and sufficiently simple procedure has been developed, specifically for the following components: 1,1,1 trichloroethane, 1,1,2 trichloroethylene, 1,1,2,2 tetrachloroethylene, carbon tetrachloride, chloroform, dichlorobromomethane and dibromochloromethane. A Head-space technique coupled with ECD-gaschromatography was used. The procedure is thoroughly discussed in the article, including the results of a ring test for a preliminary validation of this method.

Chromatography, Gas↗
PubMed1991

Loss of nocturnal decline of blood pressure in hypertension due to chronic renal failure.

The aim of this study was to assess the blood pressure profile of chronic renal failure in comparison with essential hypertension. Thirty hypertensive patients with chronic renal failure due to non-vascular nephropathies were matched by age, sex, and mean 24 h blood pressure, with 30 patients affected by uncomplicated mild-to-moderate essential hypertension. They were studied in an open hospital ward. Diet, meal times, sleep times, and activity schedules were standardized. Noninvasive, automatic, blood pressure recordings were performed for 48 h at sampling intervals of 15 min. The mean 24 h blood pressure almost coincided in the two groups. However, in essential hypertension a mean (+/- SD) nocturnal fall of systolic and diastolic blood pressure was found (12.7 +/- 3.8 and 12.9 +/- 4.8 mm Hg, respectively), while renal patients displayed an average nocturnal increase of 2.7 +/- 8.9 mm Hg and 3.7 +/- 7.8 (P less than .001). The renal patients had also higher heart rates, with a significantly blunted nocturnal fall (4.4 +/- 4.5 beats/min as compared to 9.3 +/- 3.1 beats/min of essential hypertension; P less than .001). Among the renal patients, the day-night blood pressure changes showed no significant correlation with age, creatinine clearance, hematocrit, nocturnal change in heart rate, or day or night mean blood pressure levels. These data suggest that an abnormal day-night pattern of blood pressure is present in chronic renal failure patients independently from external interfering factors. Hence, casual measurements of blood pressure confined to daytime may underestimate a hypertensive condition associated with chronic renal failure.

Adult↗
PubMed1991

Plasma levels of atrial natriuretic peptide are increased in normotensive postmenopausal women as a function of age.

The aim of this study was to assess the changes in atrial natriuretic peptide (ANP) levels before and after menopause and to test whether they depend on age or are an integral part of the hormonal changes in menopause. We measured plasma ANP, plasma renin activity (PRA), plasma aldosterone, serum estradiol-17 beta and progesterone concentrations in 103 normotensive women, either in premenopause (n = 35; mean age: 24 years), in physiological menopause (n = 34; mean age: 43 years) or surgically induced menopause (n = 34; mean age: 55 years). The last two groups were matched for duration of menopause and were comparable in their estrogen and progesterone status. PRA and plasma aldosterone concentrations decreased in postmenopausal women, whereas systolic blood pressure and ANP increased. These results were not confirmed after adjustment for age by covariance analysis. In all of the groups, plasma ANP concentrations were not significantly correlated with systolic or diastolic blood pressure, nor with plasma aldosterone, estrogen and progesterone concentrations. These correlations were not improved by correction for age. Plasma ANP concentrations were consistently correlated with age. These data suggest that the increase in plasma ANP levels found in postmenopausal women is related with age and that ANP does not play a direct role in the physiological hormonal changes of menopause.

Adult↗