PubMed Health⌕ Search

Biomedical subjects

G Stagni

Publications and source records attributed to G Stagni.

At least 19 recordsLinked to original sources
PubMed2006

Permeability and retention studies of (-)epicatechin gel formulations in human cadaver skin.

(-)Epicatechin (EC) is a major antioxidant component of grape seed extract which has become increasingly popular in topical skin preparations. This study assessed the following: (1) the permeability through cellulose membranes of EC in three different gel formulations (Carbopol 940, Klucel, and Ultrez 10); (2) the effect of three different antioxidants (butylated hydroxytoluene (BHT), alpha-tocopherol (VE), and ascorbic acid (AA)) on the stability and penetration properties of EC; and (3) the permeability and retention of EC in Ultrez 10 gels, supplemented with BHT or VE, on human cadaver skin. Permeability studies through cellulose membranes showed that different gelling agents do not significantly affect the permeability of EC (n = 7/gel; p > 0.05). BHT and VE have antioxidant properties superior to AA (p < 0.05) and preserve 100% of the initial content of EC for 28 days. Permeation studies on cadaver human skin, following application of two anhydrous gel formulations (0.5% EC in Ultrez 10 containing BHT or VE), showed that EC was not detectable in the receiving solution. However, the EC amount in viable skin increased with time, indicating that EC penetrated and was retained in the upper part of the skin for approximately 1% and 3% of the dose for the formulations containing BHT and VE, respectively.

Acrylic Resins↗
PubMed2006

Nosocomial spondylodiskitis with epidural abscess and CSF fistula cured with quinupristin/dalfopristin and linezolid.

Nosocomial infections after spinal surgery are relatively uncommon but potentially serious. The goal of diagnostic evaluation is to determine the extent of infection and identify the microorganism involved. Neuroimaging provides accurate information on correct topography, localization and propagation of the infection. Microbiological data are able to give aetiological causes. In this patient with severe, chronic polymicrobial spine infection with epidural abscess and CSF fistula due to multidrug-resistant organisms, the cure was achieved with long-term antimicrobial specific therapy with quinupristin-dalfopristin (50 days) and linezolid (100 days) with mild side effects. This positive result was due to combined medical and surgical treatment.

Acetamides↗
PubMed2003

Acute sterile meningitis as a primary manifestation of pituitary apoplexy.

Pituitary apoplexy is a rare and underdiagnosed clinical syndrome. It results from hemorrhagic infarction of the pituitary gland. In its classical form it is characterized by acute headache, ophthalmoplegia, visual loss and pituitary insufficiency. Meningeal irritation signs, clinically indistinguishable from infectious meningitis, are considered rare and have not been reported as presenting signs. We report a 53-yr-old man who was admitted to hospital following acute headache, fever, neck stiffness and paresis of the left oculomotor and abducent nerves. A lumbar puncture revealed an increased number of polymorphs but with a sterile cerebral spinal fluid. Magnetic resonance imaging (MRI) showed an intrasellar mass with central necrosis in an enlarged sella. Endocrinological evaluation demonstrated insufficient thyroid, adrenocortical, and gonadal function. Necrosis within a chromophobe adenoma was found upon surgical decompression of the sella. After surgery anterior panhypopituitarism did not recover, while ophthalmoplegia subsided. The patient is now in good health under appropriate hormonal replacement therapy.

Acute Disease↗
PubMed2002

Expression of endocrine autoantibodies in chronic hepatitis C, before and after interferon-alpha therapy.

Interferon-alpha (IFN-alpha) treatment for chronic hepatitis C (CHC) has been associated with thyroid autoimmunity and/or dysfunction. Only a few data concerning the prevalence of islet-cell or adrenal cortex autoantibodies in IFN-alpha-treated subjects are currently available. The aims of our study were to evaluate in CHC, 1) the prevalence and association of thyroid, islet-cell and adrenal autoantibodies, and 2) the appearance of endocrine dysfunction, before and after a 6 month IFN-alpha treatment. We analyzed serum samples from 203 adult patients at the time of clinical diagnosis of CHC and showed that the prevalence of thyroperoxidase (TPOAb), thyroglobulin (TGAb), TSH-receptor (TRAb), glutamic acid decarboxylase (GAD65Ab), IA-2/ICA512 (IA-2/ICA512Ab) and 21-hydroxylase (21OHAb) autoantibodies was similar to that observed among healthy control subjects of similar age and sex distribution. Among 99 patients with follow-up serum samples, 83 accepted and 16 refused IFN-alpha treatment. The IFN-alpha treatment was associated with increase of TPOAb levels in 3 subjects already positive at baseline, with progression to overt hypothyroidism in 2 of them. The de novo appearance of autoantibodies was observed in 5/80 (6%) cases for TPOAb, 1/81 (1.2%) for GAD65Ab and 2/81 (2.5%) for IA-2/ICA512Ab. Clinical or subclinical signs of either hyperthyroidism or hypothyroidism were demonstrated in 3/5 cases with de novo appearance of TPOAb. Four subjects, initially positive for either GAD65Ab or IA2/ICA512Ab, were all found negative after IFN-alpha-treatment. No subjects showed positivity for 21OHAb either at baseline or after the follow-up period. Our study suggests that, in CHC untreated patients, the prevalence of endocrine autoantibodies is similar to that observed in the general population. Furthermore, we demonstrate that IFN-alpha treatment is associated with the induction or enhancement of thyroid, but not of islet-cell or adrenal cortex autoimmunity.

Adult↗
PubMed2001

[Importation dengue].

We describe two cases of dengue fever (DF) serologicaly confirmed. In both, the clinical features are characterized by: fever, severe headache, myalgias and arthalgias, transient macule-papule rash, leukopenia and thrombocytopenia. The entire illness last few days and terminates abruptly without therapy. A history of travel to dengue-endemic areas and occurrence of other cases in a community are important reminders to include this disease in the differential diagnosis. The hemoagglutination inhibition test for DF at the Laboratory of Virology of the Istituto Superiore di Sanità on two collected sera, during the acute and convalescent phases, has showed a seroconversion. A problem is to advise patients to avoid endemic areas because the second exposure could induce DHF/dengue shock syndrome.

Adult↗
PubMed2000

Intradermal microdialysis: kinetics of iontophoretically delivered propranolol in forearm dermis.

Intradermal microdialysis permits us to measure the concentration in dermis of drugs applied to the skin. Microdialysis is especially efficient in sampling water-soluble molecules. Consequently, it appears particularly suitable to study current based delivery systems like iontophoresis that deliver ions or highly polar molecules. The purpose of this work was to evaluate the adequacy of a skin microdialysis technique to characterize and quantify the dermatopharmacokinetics of iontophoretically delivered propranolol in the dermis of healthy human volunteers. Linear microdialysis probes were inserted in the subject's forearm skin and an iontophoresis device was installed above them. Constant current was applied for two periods of 1 h each separated by a 1-h interval. Dialysate samples were collected every 6 min for 4.4 h and analyzed by HPLC. Probes were always placed in the dermis as measured by ultrasonography. Propranolol was detectable in the dialysate. It was possible to build detailed concentration vs. midtime profiles that mirrored the current applied. Elimination rate from the dermis had first-order kinetics and was similar in all subjects. Quantification of the absorption process, indexed by lag-time and area under the concentration curve showed a high inter- and intrasubject variability that did not correlate with probe depth.

Adult↗
PubMed1999

Iontophoretic current and intradermal microdialysis recovery in humans.

When microdialysis (MD) is used to study dermal delivery by iontophoresis, the effects of current may alter MD recovery through an increase in temperature, a change of pH, hyperemia, and dermal hydration. The objective of this work is to assess whether these effects of current may cause a measurable change in the retrodialysis of a model compound (sodium fluorescein, Fl). Two linear MD-probes were inserted in the forearm dermis of healthy human volunteers and perfused with Ringer's solution containing Fl. Two identical iontophoresis chambers (IC, filled with NaCl in propylene glycol) were placed over the MD-probes. Each IC included a laser Doppler flowmetry probe to monitor skin blood flow. At one IC, current was applied for two periods of 30 min each, separated by 30 min of no current. No current was applied to the control site. Dialysate samples were collected every 5 min and analyzed for Fl by HPLC. Skin blood flow increased in response to iontophoresis, on average, 570% compared to the control site. However, there was no difference in the recovery of Fl between the current-active site versus the control site, and between the period with applied current versus the period with no current. In conclusion, iontophoretic current did not affect intradermal MD recovery.

Administration, Cutaneous↗
PubMed1998

Thioridazine dose-related effects on biomechanical force platform measures of sway in young and old men.

OBJECTIVE: Thioridazine (TDZ) is associated with an increased risk of falls. The purpose of this study was to determine whether (1) thioridazine increases Biomechanics Force Platform (BFP) measures of sway in a dose-related manner, (2) there is a difference in sway between young and old men, (3) there is a correlation between sway and orthostatic changes in BP and HR. DESIGN: Seven younger (aged 20-42) and five older (aged 70-76) healthy male volunteers received, in a randomized order double-blind design, a single oral dose of 0, 25, and 50 mg of TDZ on three separate days at least 7 days apart and 75 mg on the fourth day of the study. Sway and blood pressure were measured for 24 hours. SETTING: A general clinical research center. MEASUREMENTS: Biomechanics force platform measures of postural sway were measured as the movement of the center of pressure. The elliptical area (EA) and average velocity (AV) were calculated with eyes open and eyes closed. Blood pressure and heart rate were measured for 5 minutes supine and 5 minutes standing. RESULTS: Thioridazine increases BFP sway in a dose-dependent manner. EA increased from 0.56 (SD = .51) cm2 for placebo to 0.88 (SD = 1.09) cm2 for 75 mg TDZ. AV increased from 1.07 (SD = .27) cm/sec, placebo, to 1.43 (SD = .55) cm/sec, 75 mg TDZ. Older men swayed more than younger men. Changes followed the expected time course for TDZ. EA and AV were associated with HR and BP, e.g., SBP versus ln(EA) and ln(AV) (r = -0.21 and r = -0.22, respectively; P < .0001). CONCLUSIONS: Thioridazine increases validated measures of fall risk dose dependently in young and old men. This may explain the effects of neuroleptic drugs on fall risk in older people.

Accidental Falls↗
PubMed1998

Thermoregulatory reflexes and cutaneous active vasodilation during heat stress in hypertensive humans.

During dynamic exercise in the heat, increases in skin blood flow are attenuated in hypertensive subjects when compared with normotensive subjects. We studied responses to passive heat stress (water-perfused suits) in eight hypertensive and eight normotensive subjects. Forearm blood flow was measured by venous-occlusion plethysmography, mean arterial pressure (MAP) was measured by Finapres, and forearm vascular conductance (FVC) was calculated. Bretylium tosylate (BT) iontophoresis was used to block active vasoconstriction in a small area of skin. Skin blood flow was indexed by laser-Doppler flowmetry at BT-treated and untreated sites, and cutaneous vascular conductance was calculated. In normothermia, FVC was lower in hypertensive than in normotensive subjects (P < 0.01). During heat stress, FVC rose to similar levels in both groups (P > 0.80); concurrent cutaneous vascular conductance increases were unaffected by BT treatment (P > 0.60). MAP was greater in hypertensive than in normotensive subjects during normothermia (P < 0.05, hypertensive vs. normotensive subjects). During hyperthermia, MAP fell in hypertensive subjects but showed no statistically significant change in normotensive subjects (P < 0.05, hypertensive vs. normotensive subjects). The internal temperature at which vasodilation began did not differ between groups (P > 0.80). FVC is reduced during normothermia in unmedicated hypertensive subjects; however, they respond to passive heat stress in a fashion no different from normotensive subjects.

Body Temperature Regulation↗
PubMed1998

ABR and HIV-induced impairment of the central nervous system.

This in vivo study used Auditory Brainstem Responses (ABR) to evaluate nerve transmission integrity in the course of HIV infection. 48 normoacoustic HIV+ patients (40 men, 8 women) and 10 healthy age, sex and risk-factor matched controls underwent Brainstem Evoked Auditory potentials using a standard technique. Potentials were tested at cadences of 11 and 51 stimuli per second. ANOVA and Student's T test were used for inter Center for disease Control (CDC) classes and CDC classes vs control analysis of the values of the principal wave latencies (I, III, V) and interpeak intervals (I-III, III-V, I-V). Significant impairments in nerve transmission, shown best at the 51 pps cadence, were present from the earliest stages of HIV infection and worsened as the disease progressed. These results suggest that the upper part of the brainstem may be the main target of involvement in the tract being tested. Since electrophysiological tests allow detection of nervous dysfunction in subjects while still asymptomatic, these procedures could be usefully employed in order to better define the real onset of brain damage in HIV-1 seropositive patients and monitor the speed with which these lesions evolve.

Adult↗
PubMed1997

New mathematical implementation of generalized pharmacodynamic models: method and clinical evaluation.

A new method and experimental design are presented to unambiguously estimate the transduction function (phi) and the conduction function (psi) of the generalized pharmacodynamic model: E = phi (psi * r), when measured pharmacokinetic response r is (i) drug plasma concentration and (ii) drug input rate into the systemic circulation. phi relates the observed pharmacologic effect E to the concentration at the effect site: ce = (psi * r), psi defines transfer of drug from plasma site to effect site or from input site to effect site, and * represents the convolution integral. The model functions psi and phi were expressed as cubic splines giving a very flexible description of those processes which is not biased by the structured assumptions of more conventional models, e.g., effect compartment models. The experimental design proposed addresses the problem of ambiguous identification of the model functions typical of these models; that is, there is more than one pair of very different functions describing the effect data collected after a single drug administration. We tested the hypothesis that the simultaneous fitting of at least two administrations allows the unambiguous identification of the model functions without the need for unlikely or cumbersome constraints. The performance of the mathematical implementation and the robustness of the methods with respect to measurement noise and possible failure of some assumptions, such as intraindividual variability, were tested by computer simulations. The method was then applied to the results of a clinical study of verapamil pharmacodynamics in 6 healthy subjects. Results of these studies demonstrated that the mathematical implementation does not introduce bias or artifact into the estimated functions and that the models and the proposed methods are suitable for application to clinical research. Two drug administrations were sufficient to unambiguously describe verapamil pharmacodynamics in the 6 human subjects studied.

Adult↗
PubMed1997

Bioavailability assessment from pharmacologic data: method and clinical evaluation.

A novel method is described for assessing drug bioavailability from pharmacologic data. The method is based upon a generalized model for the relationship between the observed effect (E) and the input rate (f): E = phi (ce delta * f), where * denotes convolution, ce delta is effect site unit impulse response ("amount" of drug at the effect site resulting from the instantaneous input of a unit amount of drug) and phi is transduction function (relates "amount" of drug at the effect site to E). The functions phi and ce delta are expressed as cubic splines for maximum versatility. Pharmacologic data collected after the administration of two different doses by i.v. infusion are analyzed simultaneously to estimate the function parameters. This experimental design addresses the fact that phi and ce delta cannot be uniquely estimated from the results of a single dose experiment. The unknown f from a test treatment is then estimated by applying an implicit deconvolution method to the pharmacologic data collected during that treatment. The method was tested with stimulated data. The method and the model were further evaluated by application to a clinical study of verapamil (V) pharmacodynamics in 6 healthy volunteers. Simulations showed that the method is accurate and precise in the presence of a high degree of measurement error, but large intrasubject variability in the model functions can result in biased estimates of the amount absorbed. The method produced reasonably accurate estimates of the V input rate and systemic availability (F) in the 6 human volunteers though there was a trend towards underestimation (estimated total F% = 93.6 +/- 14 vs. the true F% of 100).

Anti-Arrhythmia Agents↗
PubMed1997

The pp65 antigenaemia test as a predictor of cytomegalovirus-induced end-organ disease in patients with AIDS.

OBJECTIVE: To evaluate the predictive value of pp65 antigenaemia quantitative test for cytomegalovirus (CMV) end-organ disease in patients with advanced HIV infection. DESIGN AND PATIENTS: A prospective study in AIDS patients or HIV-infected subjects with CD4 count < 150 x 10(6)/l or CD4 percentage < 10% was carried out. Patients with a history of CMV disease or positive viraemia or antigenaemia tests and subjects under anti-herpes suppressive therapy were excluded. Clinical, ophthalmoscopic, biochemical and virological (antigenaemia test) evaluations were performed at baseline and every 1-3 months until the onset of CMV end-organ disease. SETTING: Institutional tertiary care centre. RESULTS: Forty-nine patients were evaluable for this study. End-organ disease was observed in 13 patients, 11 with at least one positive test, two with persistently negative assays. Thirteen patients without CMV disease had at least one positive test, whereas 23 always had negative tests. The 12-month Kaplan-Meier estimate of the incidence of CMV disease in our population was 30.9% and was 75% in antigenaemia-positive subjects. The negative predictive value (NPV) of the test was 92%, and the positive predictive value (PPV) was 45.8%. However, the NPV of quantitative (> 20 cells) antigenaemia assay was 92.1% and the PPV was 90.9%. CONCLUSIONS: The antigenaemia test is a quick, simple and easy to perform assay for diagnosing CMV infection. The NPV is fairly good, as is the PPV when the quantitative method (> 20 positive cells) is used. This test could be used as an alternative to polymerase chain reaction in order to select patients at higher risk of CMV disease who can be treated with pre-emptive anti-CMV therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Simultaneous analysis of verapamil and norverapamil enantiomers in human plasma by high-performance liquid chromatography.

An improved HPLC method for the simultaneous determination of the enantiomers of verapamil (V) and its major metabolite norverapamil (NV) in human plasma samples is presented. NV is acetylated immediately to N-acetylnorverapamil (ANV) in the extraction solvent (2% butanol in hexane). Acetylation is so rapid that it does not delay sample processing. ANV and V enantiomers are then separated on an alpha 1-acid glycoprotein chiral column with a mobile phase of phosphate buffer (0.01 M, pH 6.65) and acetonitrile. The fluorescence detector wavelengths are set at 227 nm for excitation and 308 nm for emission. Introduction of the internal standard (I.S.) (+)-glaucine improves accuracy, precision and robustness of the method. The assay is sensitive and specific. Baseline separation is achieved for both V and ANV. Limits of quantitation are 3 ng/ml for V and 2 ng/ml for NV (single enantiomer) with precision and accuracy better than 15% at those levels. Detector response is linear in the range tested (3-200 ng/ml for V and 2-100 ng/ml for NV, single enantiomer). This assay has been applied to a clinical study of the pharmacodynamics of V involving six healthy volunteers.

Acetonitriles↗
PubMed1995

Prevalence of HBV, HDV and HCV hepatitis markers in HIV-positive patients.

Since HIV infection could condition the natural history of parenterally transmitted viral hepatitis (HBV, HCV, HDV), with possibly differing effects in different risk groups, we decided to retrospectively examine sera from a cohort of 637 HIV seropositive patients in different stages of infection, seen from 1985 to 1992, to study the prevalence and temporal course of these infections. Virological markers of HBV, HCV and HDV were determined by ELISA and RIBA methods. The severity of HIV infection was higher in homosexuals than in drug addicts. Prevalence of antiHBc antibodies was 82% in drug addicts and 77% in homosexuals, whereas antiHCV antibodies prevalence was 72% in drug addicts and only 7% in homosexuals (p < 0.000001). When only antiHBc-positive patients were considered, there was a significant difference in antiHBs antibodies between drug addicts (DA) and homosexuals (OR for DA 0.29, 95% CI 0.08/0.83, p = 0.02), suggesting that drug addicts are less able to produce a protective response. This fact cannot be explained by the severity of HIV infection (which was higher among the homosexual group) and suggests some immunodepressive effect of drug abuse. Delta infection was only detected in the drug addict group, and the prevalence was low. Finally, we cannot confirm the interference of HCV infection with the speed of HBsAg clearance: in this study the prevalence of HBsAg was almost the same in HCV-positive and negative patients.

Antigens, Viral↗
PubMed1995

Role of antigenemia assay in the early diagnosis and prediction of human cytomegalovirus organ involvement in AIDS patients.

The role of an antigenemia assay in the diagnosis and prediction of human cytomegalovirus (HCMV) disease in AIDS patients was evaluated. The clinical history of 62 patients with advanced HIV infection from whom a total of 248 blood samples were drawn and tested by the HCMV antigenemia assay was examined retrospectively. Between December 1992 and January 1994, 28 episodes of HCMV disease with organ involvement were recorded; the antigenemia assay was positive in 23 of them (82.1%). In particular, this test was positive in 11 of 12 (91.6%) first episodes and in 3 of 3 (100%) recurrent episodes occurring in patients not receiving maintenance therapy. The same test was positive in 9 of 13 (69.2%) recurrent episodes occurring in patients receiving maintenance therapy. The first occurrence of HCMV disease was always preceded by a positive antigenemia assay 2 and 4 months before diagnosis (in all 7 patients of the 7 for whom a blood sample was available before HCMV disease). A positive antigenemia test result was not always followed by organ involvement, but a high positive cell count (> 100/200,000 polymorphonuclear leukocytes) strongly correlated with the appearance of HCMV disease in the following 1 to 3 months (100% of cases). The antigenemia assay is a useful and reliable indirect method for the diagnosis and prediction of HCMV end-organ disease in severely and persistently immunocompromised AIDS patients.

AIDS-Related Opportunistic Infections↗