Biomedical subjects

S Rossi

Publications and source records attributed to S Rossi.

At least 91 records · Page 5Linked to original sources

PubMed2002

[Rendu-Osler-Weber syndrome. Pulmonary arteriovenous fistulas. A report of three cases].

Hereditary hemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber syndrome, is a rare disorder that is closely linked to the development of pulmonary arteriovenous malformations (PAVM). Diagnosis can be based on clinical signs such as upper respiratory tract changes or recurrent hemorrhagic events. Nevertheless, pulmonary involvement, a prognostic factor, may remain undetected. In the three HTT cases with PAVM we report, the following diagnostic information was obtained non-invasively: shunt fraction measurements (breathing 100% oxygen), echocardiographic contrast studies, and three-dimensional helical computed tomographs. Arteriography demonstrated a single PAVM in one case and the patient underwent successful coil embolization, with clinical and functional improvement.

Adult↗

PubMed2002

Damaging effects of advanced glycation end-products in the murine macrophage cell line J774A.1.

The interaction of reducing sugars, such as aldose, with proteins and the subsequent molecular rearrangements, produces irreversible advanced glycation end-products (AGEs), a heterogeneous class of non-enzymatic glycated proteins or lipids. AGEs form cross-links, trap macromolecules and release reactive oxygen intermediates. AGEs are linked to aging, and increase in several related diseases. The aim of this study was to assess, in a murine macrophage cell line, J774A.1, the effects of 48 h of exposure to glycated serum containing a known amount of pentosidine, a well-known AGE found in the plasma and tissues of diabetic and uremic subjects. Fetal bovine serum was incubated with ribose (50 mM) for 7 days at 37 degrees C to obtain about 10 nmol/ml of pentosidine. The cytotoxic parameters studied were cell morphology and viability by neutral red uptake, lactate dehydrogenase release and tetrazolium salt test. In the medium and in the intracellular compartment, bound and free pentosidine were evaluated by HPLC, as sensitive and specific glycative markers, and thiobarbituric acid reactive substances (TBARs), as index of the extent of lipid peroxidation. Our results confirm that macrophages are able to take up pentosidine. It is conceivable that bound pentosidine is degraded and free pentosidine is released inside the cell and then into the medium. The AGE increase in the medium was combined with an increase in TBARs, meaning that an oxidative stress occurred; marked cytotoxic effects were observed, and were followed by the release of free pentosidine and TBARs into the culture medium.

Animals↗

PubMed2002

Somatosensory processing during movement observation in humans.

OBJECTIVES: A neural system matching action observation and execution seems to operate in the human brain, but its possible role in processing sensory inputs reaching the cortex during movement observation is unknown. METHODS: We investigated somatosensory evoked potentials (SEPs), somatosensory evoked fields (SEFs) and the temporal spectral evolution of the brain rhythms (approximately 10 and approximately 20 Hz) following electrical stimulation of the right median nerve in 15 healthy subjects, during the following randomly intermingled conditions: a pure cognitive/attentive task (mental calculation); the observation of a motoric act (repetitive grasping) with low cognitive content ('Obs-grasp'); and the observation of a complex motoric act (finger movement sequence), that the subject had to recognize later on, therefore reflecting an adjunctive cognitive task ('Obs-seq'). These conditions were compared with an absence of tasks ('Relax') and actual motor performance. RESULTS: The post-stimulus rebound of the approximately 20 Hz beta magnetoencephalographic rhythm was reduced during movement observation, in spite of little changes in the approximately 10 Hz rhythm. Novel findings were: selective amplitude increase of the pre-central N(30) SEP component during both 'Obs-grasp' and 'Obs-seq', as opposed to the 'gating effect' (i.e. amplitude decrease of the N(30)) occurring during movement execution. The strength increase of the 30 ms SEF cortical source significantly correlated with the decrease of the approximately 20 Hz post-stimulus rebound, suggesting a similar pre-central origin. CONCLUSIONS: Changes took place regardless of either the complexity or the cognitive content of the observed movement, being related exclusively with the motoric content of the action. It is hypothesized that the frontal 'mirror neurons' system, known to directly facilitate motor output during observation of actions, may also modulate those somatosensory inputs which are directed to pre-central areas. These changes are evident even in the very first phases (i.e. few tens of milliseconds) of the sensory processing.

Adult↗

PubMed2002

Inter-observer reproducibility and responsiveness of a clinical severity scale in surgically treated carpal tunnel syndrome.

OBJECTIVES: To test a recently proposed carpal tunnel syndrome (CTS) clinical severity scale for reproducibility between two observers (neurosurgeon and neurophysiologist) before surgery, for responsiveness to changes in clinical status 6 months after surgery, and for correlations with the electrophysiological findings and 'Boston Carpal Tunnel Syndrome Questionnaire' (BQ). MATERIAL AND METHODS: The tests were applied prospectively to a consecutive series of 254 hands with idiopathic CTS, referred for surgical decompression. The hands belonged to 219 subjects (177 women and 42 men, mean age 55.6). RESULTS: Percentage agreement between the two observers in assigning severity to the same class was 78% and Cohen coefficient kappa was 0.69 (P < 0.001). The scale was found to be responsive to changes in clinical status after surgery. Direct correlations were also found between the scale and patient age, duration of symptoms, BQ scores and the neurophysiological severity scale. The significance of these associations was maintained for 6 months after the operation. CONCLUSION: This clinical severity scale is simple, reproducible and sensitive for evaluating severity of CTS in patients undergoing surgery.

Adult↗

PubMed2002

Validation of a food frequency questionnaire for nutritional calcium intake assessment in Italian women.

OBJECTIVE: To evaluate a food frequency questionnaire assessing calcium intake in women. DESIGN: : Estimates of calcium intake from the food frequency questionnaire were compared with those from 14 day records from 206 Caucasian women aged 25-75 y in Siena, Italy. SUBJECTS: Subjects were randomly recruited from the residents list of the city of Siena, Italy. Of the 250 initially recruited, 39 did not meet the inclusion criteria or failed to complete the diet record and five outliers were excluded before the statistical analysis on the basis that their diet record was unlikely to represent habitual intake. RESULTS: Mean dietary calcium intakes were 829+/-255 (s.d.) mg/day from the questionnaire and 818+/-260 (s.d.) mg/day from the diet record. The mean difference in intake by the two methods (-11.3+/-116.4 mg/day) did not differ significantly from zero. Specificity in classifying women consuming less than 800 mg/day calcium was 86.6%, and sensibility in classifying women consuming more than 800 mg/day calcium was 89.4%. CONCLUSIONS: The food frequency questionnaire could be used in epidemiological studies to assess calcium intake in young to elderly women. The specificity in identifying low calcium intake subjects makes it useful also as an educational tool in diet counselling and for prescribing calcium supplementation.

Adult↗

PubMed2002

Ophthalmic vehicles containing polymer-solubilized tropicamide: "in vitro/in vivo" evaluation.

Commercial 1.0% aqueous tropicamide (TR) eyedrops are buffered to pH 4.4-5.0 to produce sufficiently stable solutions of the weakly basic, poorly soluble drug. These acidic solutions, however, are irritants and may induce copious lachrimation, thus reducing the drug bioavailability. The aim of the present study was to evaluate some solubilizing agents for the preparation of 1.0% TR ophthalmic solutions adjusted at physiologically compatible pH, potentially showing increased eye tolerance, activity, and stability when compared with standard commercial eyedrops. The tested solubilizers were two non-ionic surfactants-Tyloxapol (TY) and Cremophor EL (CR) and one polymer, Pluronic P85 (PL). Four stable 1% TR formulations, containing 3% TY, 7.5% CR, 15% PL, or 5% CR + 10% PL were submitted to mydriatic activity tests in rabbits. They improved to a small but statistically significant extent the AUC for mydriatic effect of TR in the test animals when compared with commercial 1.0% TR eyedrops.

Animals↗

PubMed2002

Questionnaire survey of perioperative antibiotic prophylaxis in Italian surgical departments.

Correct antibiotic prophylaxis reduces the incidence of postoperative infections. 600 questionnaires on perioperative antibiotic prophylaxis were sent to Italian Surgical Departments. Each questionnaire included a series of 17 multi-choice-questions concerning the specific approach of the department to: organization, type, timing, duration, auditing of prophylaxis. 435 departments (72.5%) responded to the questionnaire; 50 of these were blank, so 385 out of 435 (88.5%) were suitable for statistical evaluation. Results were as follows: 90.5% of departments perform some form of prophylaxis under the control, in 90.5% of cases, of surgeons; 89.3% differentiate antibiotics according to class of operation; 67.4% give the antibiotic preoperatively and prefer i.v. injection (61.0%), mostly in the ward (56.2%); in 33.3% of cases the prophylaxis is standard (more than 2 doses), but 55.8% of Italian surgeons do not give a boost-dose in operations longer than 3 h; 54.2% of patients receive a cephalosporin (mostly III generation), with a rotation of molecules in 53.9% of cases; 71.7% of departments register the incidence of infections, but only 43.2% control the patients 30 days after surgery; finally, 54.2% of departments work together with a bacteriology laboratory active 24 hours, while in 81.7% of cases the hospital has an Infection Committee which meets together usually without a programmed date (60.3%). In conclusion, antibiotic prophylaxis in Italian Surgery Departments appears adequate, even though some problems still remain regarding time-dose-duration-schedule, rotation of molecules, excess of cephalosporins, availability of a 24-h bacteriological laboratory and infection surveillance after discharge.

Antibiotic Prophylaxis↗

PubMed2002

Classical swine fever (hog cholera) in wild boar in Europe.

Classical swine fever (CSF) is of increasing concern in Europe where wild boar appear to play an important epidemiological role. In most parts of the continent, demographic trends are on the increase, due to improvement in game management. As a result of higher densities, populations become more susceptible to various infectious diseases, among which CSF is cause for particular concern. Wild boar do not appear to be a classic reservoir in most cases, but nevertheless may perpetuate foci of infection over the long term, constituting a real threat for the pig farming industry. Since the infection does not appear to spread easily in natural populations of free-ranging wild boars, control of the disease may be feasible. However, most of the appropriate measures, such as banning hunting, are not considered acceptable. Consequently, the expertise of wildlife disease specialists is required to help solve the problem when it occurs.

Animals↗

PubMed2001

Protein kinase A activity in permeabilized cells as an approximation to in vivo activity.

Permeabilized germlings from the dimorphic fungus Mucor rouxii were used for in situ measurement of protein kinase A (PKA) activation, to compare the results with those obtained in vitro at low or high (nonlinear) enzyme concentrations. The apparent total activity per cell when measured in situ is 5- to 10-fold lower than the in vitro measured activity in crude extracts from those cells. Polyamines and NaCl stimulate the activity in situ. The apparent relative specific activity of the in situ measured PKA toward four peptide substrates is similar to the results obtained in vitro at high holoenzyme concentration and not to those obtained with the free catalytic subunit. Saturation in the activation of PKA by cAMP in situ is attained at low concentrations (2 to 10 microM), while in vitro, at high holoenzyme concentration, no saturation was attained up to 1 mM cAMP (V. Zaremberg et al. Arch. Biochem. Biophys. 381, 74-82, 2000). Activation of PKA by site-selective cAMP analogs is assayed in situ and in vitro at two enzyme concentrations. Site B-selective cAMP analogs are good activators of PKA at low enzyme concentration in vitro but poor activators either at high enzyme concentration in vitro or in permeabilized cells. A physiological correlation with the behavior of site-selective analogs in situ is demonstrated in vivo when assaying the effect of increasing concentrations of site-selective cAMP analogs on the impairment of polarized growth of M. rouxii spores.

Binding Sites↗

PubMed2001

Urinary calcium excretion in the monitoring of bone metastases from prostatic carcinoma.

BACKGROUND: One of the greatest problems in treating advanced prostate carcinoma is monitoring the therapeutic response of bone metastases. As these metastases are mainly osteosclerotic and lead to a markedly increased bone calcium requirement that may give rise to an imbalance in calcium homeostasis, the authors investigated whether changes in calcium balance may be useful for evaluating the response of bone metastases to treatment. METHODS: The study involved 268 prostate carcinoma patients: 142 in Stage A-C2 (International Union Against Cancer [UICC] staging system, 1998) and 126 with bone metastases who had failed to respond to hormone therapy and were receiving chemotherapy. Prostate-specific antigen (PSA), calcium and phosphate metabolism, and the main bone formation and resorption markers were all assayed before and after chemotherapy. RESULTS: Of the 126 patients on chemotherapy, 109 were evaluable for response: according to standard criteria, 25 (23%) had improved, 43 (39.5%) were unchanged, and 41 (37.5%) had worsened. All of the improved and 16 unchanged patients had decreased PSA and bone marker levels and an increased urinary calcium/creatinine ratio (UCa/Cr); the worsened patients had increased PSA and bone marker levels, and their UCa/Cr decreased after only six treatment cycles. PSA and UCa/Cr were the biochemical markers whose changes showed the best agreement with treatment response. CONCLUSION: The UCa/Cr ratio was the most useful marker of clinical response, mainly because it allowed an early decision to continue or to stop chemotherapy. Furthermore, UCa/Cr and PSA together identified a percentage of patients classified as unchanged on the basis of standard criteria but whose condition had actually improved.

Bone Neoplasms↗

PubMed2001

Isothermal and non-isothermal characterization of catalytic nylon membranes chemically grafted: dependence on the grafting percentage.

The behaviour of five different hydrophobic beta-galactosidase derivatives, obtained by grafting different amount of butylmethacrylate (BMA) on planar nylon membranes, has been studied under isothermal and non-isothermal conditions.Under isothermal conditions the effect of the grafting percentage on the enzyme activity has been studied as a function of pH, temperature and substrate concentration. Independently from the parameters under observation, the yield of the catalytic process reaches the maximum value at a grafting percentage value equal to 21%. The apparent K(m) values result linearly increasing with the increase of the grafting percentage, while the apparent V(max) exhibits a maximum value.Under non-isothermal conditions, a decrease of the apparent K(m) values and increase of the apparent V(max) has been found in respect to the same values obtained under isothermal conditions.The percentage activity increases induced by the presence of a temperature gradient have been found to decrease with the increase of the percentage of graft BMA.A parameter correlating the percentage increase of enzyme activity under non-isothermal conditions with the hydrophobicity of the catalytic membrane has also been identified. This parameter is the ratio between thermoosmotic and hydraulic permeability.Results have been discussed in terms of reduction of diffusion limitations for substrate and products movement towards or away from the catalytic site by the process of thermodialysis.The usefulness of using non-isothermal bioreactors in industrial biotechnological processes has been confirmed.

Journal Article↗

PubMed2001

Multiresidual method for the gas chromatographic analysis of pesticides in honeybees cleaned by gel permeation chromatography.

The analysis of several organophosphorus and carbamate pesticide residues in the bodies of honeybees using gas chromatography (GC) and gel permeation chromatography (GPC) clean-up is described. Freeze-dried or lyophilized insect samples were blended with diatomaceous earth (Extrelut) then underwent elution with methylene chloride. This extraction method has shown good recovery on various spike standard levels. Samples are cleaned up by GPC with a Bio Beads SX 3 column and a cyclohexane-ethylacetate (1:1) eluant. Organophosphorus and carbamate compounds are quantified using capillary gas chromatography. Good linearity ranges were observed for all compounds. The extraction process was rapid and results were good, despite the complexity of the matrix on which it was applied. It allowed a reduction both in cost and the consumption of solvents, thereby safeguarding the health of the analyst and the environment. Environmental monitoring using bees was confirmed to be a valid procedure.

Animals↗

PubMed2001

Dual X-ray absorptiometry and bone ultrasonography in patients with Rett syndrome.

This study evaluated bone status and bone turnover in 82 females (ages 2-21 years) with the Rett Syndrome (RS) and 82 age-matched controls. Bone mineral density (BMD) by dual X-ray absorptiometry (DXA) at the ultradistal and proximal radius and ultrasonographic (QUS) parameters at the calcaneus [speed of sound(SOS), broadband ultrasound attenuation(BUA), and stiffness] and at the phalanxes (amplitude dependent speed of sound: AD-SOS) were measured. We also measured serum calcium, phosphate, 25-hydroxyvitamin D, and biochemical markers of bone turnover. DXA and QUS parameters were significantly lower in patients with RS compared with controls and, among RS alone, in those treated with anticonvulsants and in those who are nonambulatory. Ambulatory RS patients showed QUS and DXA parameters significantly greater than nonambulatory patients but significantly lower than controls. Patients with RS treated with anticonvulsants presented QUS and DXA parameters lower than those of other RS. In RS patients, walking significantly influences BMD-UD, BMD-P, SOS. BUA. and Stiffness. Serum 25-hydroxyvitamin D was significantly lower in RS than in controls. These results suggest that ambulatory status, to a major extent, and anticonvulsant therapy certainly play an important role in the reduction of bone mass and bone quality, but they cannot completely explain the altered bone status. Whatever the cause, girls with RS present abnormal bone status with an increase in the risk of fracture.

Absorptiometry, Photon↗

PubMed2001

Avidity analysis of the human immune response to a chitin binding protein of Toxoplasma gondii.

A 30-33 kDa electroeluted fraction of T. gondii tachyzoites improved discrimination between acute and chronic phase sera when used instead of the whole tachyzoite extract in an avidity-ELISA. In order to identify the components of these fractions, crude tachyzoite antigen was fractionated by anionic exchange chromatography. The 30-33 kDa antigen cluster eluted in the not-bound fraction could account for a large proportion of the antibody response against the 30-33 kDa electroeluted fraction. According to the N-terminal sequence data, this antigen fraction is composed mainly of SAG1 and another protein with high homology to chitin binding proteins from plants.

Animals↗

PubMed2001

Transurethral radiofrequency thermal ablation of prostatic tissue: a feasibility study in humans.

OBJECTIVES: To evaluate the feasibility and efficacy of ablating prostatic tissue by inducing thermal lesions using radiofrequency (RF) energy delivered transurethrally through electrodes mounted on a Foley-like catheter. METHODS: Twenty male patients, candidates for radical cystoprostatectomy to treat bladder carcinoma, underwent RF prostate ablation 1 to 8 days before surgery (mean 2.8). Stainless steel, internally cooled, 2-cm-long electrodes mounted on a Foley-like catheter were used to deliver RF energy to the prostatic tissue. Semicircular electrodes were used in 10 patients (group A) and circular electrodes were used in the remaining 10 patients (group B). The urethral, rectal, and prostatic tissue temperatures were recorded. Histologic step sections were performed on whole mounts of the prostates to define the volume of the thermal lesions. RESULTS: The mean RF energy delivered was 36.5 kJ (range 26.4 to 53.1) in group A and 82.3 kJ (range 38 to 149) in group B. The intraprostatic temperatures were between 44 degrees C and 80 degrees C in group A and between 60 degrees C and 119 degrees C in group B. The urethral and rectal temperatures never exceeded 42 degrees C. No major complications occurred. After the RF procedure, 5 patients who received more than 75 kJ of energy could not void and required catheterization. The mean prostate volume was 11.54 cm(3) for group A and 24.02 cm(3) for group B. The mean volumes of the thermal lesions and their relative percentages in relation to the whole prostate in groups A and B were, respectively, 1.69 cm(3) and 15% and 6.91 cm(3) and 29% (P = 0.049). Analysis of variance showed a significant correlation between the thermal lesion volume and the energy delivered, regardless of the electrode shape (P = 0.001). CONCLUSIONS: Satisfactory thermal ablation of prostatic tissue can be achieved using RF electrodes mounted on a Foley-like catheter. The procedure is effective, simple, and safe and, therefore, can be used in pilot clinical studies on patients with benign prostatic hyperplasia.

Aged↗

PubMed2001

Characterization of chitosan hydrochloride--mucin rheological interaction: influence of polymer concentration and polymer:mucin weight ratio.

The aim of the present work was to investigate the influence of polymer concentration and polymer:mucin weight ratio on chitosan--mucin interaction, assessed by means of viscosimetric measurements. Two hydration media, distilled water and 0.1 M HCl, were used. Chitosan solutions were prepared at concentrations greater than the characteristic entanglement concentration and mixed with increasing amounts of porcine gastric mucin. Viscosity measurements were performed on the polymer--mucin mixtures and on polymer and mucin solutions having the same concentrations as in the mixtures. The flow curves were fitted according to a modified form of Cheng--Evans equation in order to obtain the relevant model parameters: low shear viscosity eta(0) and high shear viscosity eta(infinity), indexes of the sample structure at rest and upon high shear, respectively. The formation of chitosan--mucin interaction products was determined on the basis of the changes in eta(0) and eta(infinity) of the mixtures as a function of polymer:mucin weight ratio. Rheological synergism parameter was also calculated. The results obtained suggest that two different types of rheological interaction occur between chitosan and mucin in both media, depending on polymer concentration and polymer:mucin weight ratio: one is characterized by a minimum in viscosity and occurs at higher polymer:mucin weight ratio, the other one produces a positive rheological synergism and is observed in presence of an excess of mucin. Only the last one causes a 'strengthening' of the mucoadhesive interface and it is responsible for the mucoadhesive joint. This hypothesis is confirmed by tensile stress measurements performed on HCS solutions in presence of mucin dispersions at different concentrations.

Animals↗

PubMed2001

Successful treatment of TIPS-induced hepatic failure with an hourglass stent-graft: a simple new technique for reducing shunt flow.

A simple new technique for creating an hourglass reducing stent-graft by means of targeted balloon expansion of each end of a commercially available device is presented. A 67-year-old man with progressive hepatic failure after TIPS creation was treated. A 48-mm-long Jostent stent-graft was placed inside the TIPS through a 10-F introducer and fully expanded only at the proximal and distal ends, resulting in an hourglass shape. Immediate increase of portal pressure was achieved, followed by complete clinical recovery. Advantages of covered versus bare reducing stents are discussed.

Aged↗

PubMed2001

Brain-stem compression in vertebrobasilar dolichoectasia. A multimodal electrophysiological study.

OBJECTIVE: To evaluate the effects of mechanical compression of the brain-stem in patients with vertebrobasilar dolichoectasia (VBD). METHODS: In the framework of a prospective, observational study that collected clinical and laboratory data in patients with VBD, we studied 20 patients with compression of the brain-stem due to ectatic, tortuous basilar or vertebral arteries. Patients with cerebral lesions other than small lacunae in the white matter of the cerebral hemispheres were excluded from the study. Patients underwent vestibular and auditory function testing, including brain-stem auditory evoked potentials (BAEPs), blink reflex (BR), somatosensory evoked potentials (SEPs), and motor evoked potentials (MEPs). RESULTS: Almost all of the patients complained of auditory or vestibular symptoms and none had symptoms or signs of impairment of long tracts or the facial and trigeminal nerves. The most consistent findings were BR abnormalities with prolongation of ipsilateral R1 latency in cases of compression of the pons (10/16) and prolongation of the R2 and R2c latencies with compression of the medulla oblongata (5/15). Subclinical impairment of corticospinal pathways was found in 13 out of 25 instances of compression, and this was more frequent with compression of the pons. Abnormal BAEPs or SEPs were less frequently encountered, and only in cases with compression of the pons. CONCLUSIONS: Neurovascular compression of the brain-stem, even with severe distortion, is seldom associated with overt clinical signs, whereas subclinical dysfunctions are relatively frequent. The central pathways of the BR and the corticospinal pathways are more susceptible to compression than acoustic and sensory pathways. BR, MEP and BAEP data provide a functional evaluation of the brain-stem and some cranial nerves, which is lacking in imaging studies. Functional investigations may be useful in the long-term management of these patients, since VBD may be progressive and surgical correction may be required at some stage.

Adult↗