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Biomedical subjects

R Pozzi

Publications and source records attributed to R Pozzi.

At least 19 recordsLinked to original sources
PubMed2006

Rapid analysis of tile industry gaseous emissions by ion mobility spectrometry and comparison with solid phase micro-extraction/gas chromatography/mass spectrometry.

The present paper reports on a rapid method for the analysis of gaseous emissions from ceramic industry, based on ion mobility spectrometry (IMS) as a means for on-site monitoring of volatile organic compounds (VOCs) produced during tile baking. IMS was calibrated with a set of reference compounds (i.e. ethyl acetate, ethanol, ethylene glycol, diethylene glycol, acetaldehyde, formaldehyde, 2-methyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 1,3-dioxolane, 1,4-dioxane, benzene, toluene, cyclohexane, acetone, acetic acid) via air-flow permeation. The technique was tested on a laboratory-scale kiln and tiles prepared with selected glycol- and resin-based additives. Finally, the analytical method was applied to emissions from two industries in the Modena (Italy) ceramic area. The results of all experimental phases were compared to those obtained by solid phase micro-extraction/gas chromatography/mass spectrometry (SPME/GC/MS). IMS showed potential as a real-time monitoring device for quality assessment in ceramic industry emissions. IMS spectra, SPME/GC/MS data, relationship between additives/baking conditions and produced VOCs and advantages and limitations of both techniques will be discussed.

Air Pollutants↗
PubMed2002

Phototoxic effect of fluoroquinolones on two human cell lines.

Photosensitization induced by the fluoroquinolone ofloxacin (OFLX) has been studied using two human cell lines, HL60 and K562, two UV wavelengths, 290 and 330 nm, and two different exposure protocols, acute and protracted. The examined endpoints are the cellular lethality and recovery and the membrane changes produced by the oxidative damage, studied using cloning and counting techniques and the measurement of the generalized polarization (GP) of the fluorescent membrane probe 2-dimethylamino-6-lauroyl-naphthalene (Laurdan). The results show that: (i) the photosensitizing effect is detectable at concentrations similar to those found in patients treated with OFLX only when the cells are irradiated with 330 nm; (ii) the amount of photodamage is a function of the drug concentration and of UV dose and persists also after the removal of the drug; (iii) during the first 24 h after OFLX treatment, a large decrease of the cell number can be observed due to cell lysis; (iv) the OFLX is inserted in the cell membranes at concentrations directly related with the drug concentration and incubation time; (v) the OFLX produces an increase in the GP values similar to that produced by membrane lipid oxidation which persists for hours after the removal of the drug. The overall results suggest the cell membrane as the main target of the OFLX adverse action, with a possible mechanism involving the formation of reactive oxygen species (ROS), which triggers, in turn, the lipid peroxidation chain reaction.

Anti-Infective Agents↗
PubMed2001

Experimental upgrades of membrane introduction mass spectrometry for water and air analysis.

Some improvements to the membrane introduction mass spectrometry (MIMS) technique, resulting in low-ppt detection limits for volatile organohalogen compounds (CX) in water (namely, chloroform, bromoform, bromodichloromethane, chlorodibromomethane, tetrachloroethylene, trichloroethylene, 1,1,1-trichloroethane, and carbon tetrachloride) and low-microgram per cubic meter detection limits for benzene, toluene, ethylbenzene, and xylenes (BTEX) in gaseous samples, are shown. A static MIMS configuration was compared to a dynamic one, the former requiring longer time to obtain the analytical response. A cryotrapping preconcentration step is introduced and linearity of response, mixture effects, and detection limits are presented. The instrumental setup consists of a hollow fiber silicone membrane, a water or air container, a cryofocusing trap based on Tenax adsorbent, a Peltier cell, and a Varian ion trap benchtop mass spectrometer is described. This instrumental setup, which we named membrane extraction trap focusing mass spectrometry, allowed the detection of CX in water at a concentration as low as 8 ppt and of benzene in air at 0.1 microg/m3. The whole assembly shows great potential for on-site routine monitoring of drinking water resources and urban and indoor air under current EU and Italian regulations.

Journal Article↗
PubMed2001

Accurate mass measurement of synthetic analogues of prazosine by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) has been investigated as a tool for accurate determination of the molecular mass of synthetic analogues of prazosine, a molecule used for the treatment of hypertension. Samples were dissolved in methanol, mixed with mass calibration standards, and crystallised on the target with alpha-cyano-4-hydroxycinnamic acid as matrix. Acquisition of spectra was rapidly completed in reflectron mode, allowing high resolution (6000-10000) and sensitive (about 1-10 pmol of sample on target) determination of the synthetic products. The results show the effectiveness of MALDI-TOFMS for accurate mass determination of these fairly large molecules, which are otherwise difficult to analyse by other high-resolution mass spectrometric techniques.

Adrenergic alpha-Antagonists↗
PubMed2000

[Aortic dissection. A diagnostic hypothesis that is frequently discussed].

Aortic dissection is a dramatic event which too often carries an ominous prognosis. The characteristic clinical presentation has been well described in medical texts and cannot be misdiagnosed. However, in some not infrequent cases, symptoms and signs may be so misleading and subtle that a subsequent catastrophic evolution then seems unexpected. The diagnosis may be easily confirmed or excluded by modern diagnostic tools such as transesophageal echocardiography, magnetic resonance imaging or spiral computed tomography, which all offer such accurate anatomic images of the aortic wall that nowadays it is possible to diagnose even those minimal lesions that can precede dissection, such as intramural hemorrhages or penetrating ulcers. However, these techniques are complex, costly and require experienced operators for optimum sensitivity and accuracy. Their use in patients with suspected acute aortic syndromes is of proven necessity. However, how often is all this feasible in a crowded Emergency Department where hundreds of patients with aspecific and overlapping symptoms and signs all require immediate attention? Furthermore, how often is a subtle intriguing initial presentation then followed by fatality, which might also come about some days later? Can failing to make an early diagnosis be cause for prosecution for having given a faulty diagnosis or might it be accepted as a risk related to the imprecise, probabilistic nature of the medical approach to the diagnosis? How can an Emergency Department doctor produce a reliable document of his way of proceeding in order to offer verifiable legal proof of his methodological integrity and thus be able to avoid misinterpretation of guilt? It is all too easy to judge overlooked clinical recognition when the clear and "simple" pathological diagnosis is available, if one does not consider the complexity of the disease and its possible manifestations in the single patient. In order to answer these questions it is necessary to collect the experience of doctors and others involved in this field. It is the aim of this paper and the clinical case presented to stimulate discussion and initiate the task in hand.

Aortic Dissection↗
PubMed2000

[True and presumed contraindications of beta blockers. Peripheral vascular disease, diabetes mellitus, chronic bronchopneumopathy].

Traditional contraindications to beta-blockers are peripheral vascular diseases, diabetes mellitus, chronic obstructive pulmonary disease (COPD) and asthma. Recent data seem to show that rigorous application of these rules are not completely justified and indicate that many patients would be inappropriately excluded from the beneficial effects of this therapy. Appraisal of clear guidelines for a safe use of beta-blockers is thus mandatory for the clinician. A brief review of the effects of beta-adrenergic receptor blockade is offered. The therapy is aimed at blocking beta 1-receptors. On the other hand, the block of beta 2-receptors causes the well known side effects, i.e. vasoconstriction, delayed response to hypoglycemia in diabetic patients, bronchoconstriction. From the first compound, propranolol, with uniform action on beta 1 and beta 2-receptors, further generation of beta-blockers were subsequently developed: beta 1-selective, with intrinsic sympathomimetic activity, and with associated vasodilating "ancillary" property. Some favorable reduction in collateral effects has thus been obtained with new compounds, without reaching complete safety. Examination of exclusion criteria applied in clinical trials offers no useful indications because of their imprecise definition. Examination of the literature and a more accurate understanding of the diseases, traditionally considered contraindications, may help setting up a uniform and clear path: peripheral vascular disease: beta-blockers should be avoided only in those patients with vasospastic disorders, rest pain with severe peripheral vascular disease or nonhealing lesions. In patients with mild to moderate disease, beta-blockers can be prescribed, but careful surveillance for any changes in symptoms related to intermittent claudicatio should be achieved; diabetes mellitus: previous apprehension for the lessening reaction to hypoglycemia in patients treated with insulin has been retracted. Beta-blockers are not contraindicated in these patients. Some caution should be addressed when signs of autonomic disease are present or in patients with difficult glycemic control. Patients on oral long-acting antidiabetic drugs should not be neglected. The risk of prolonged and paucisymptomatic hypoglycemia while taking beta-blocker agents is somewhat more relevant than in patients treated regularly with insulin; COPD and asthma: confusion may arise if rigorous definition of these diseases and their severity is not applied following the guidelines of the American Thoracic Society. Because bronchial hyperreactivity seems the crucial factor in determining collateral effects to beta-blocker agents, agreement can be reached on the following statements. Beta-blockers are contraindicated a) when history of asthma is present, b) when COPD is moderate to severe, i.e. with FEV1 reduction < 50% of the predicted value, c) in patients on chronic bronchodilator treatment, d) in chronic airflow limitation with evidence of > or = 20% reversibility in airway obstruction in response to inhaled salbutamol. When FEV1 is > 50% of the predicted value, beta-blockers can be given, providing adequate control of stability of ventilatory conditions.

Adrenergic beta-Antagonists↗
PubMed1999

Membrane inlet mass spectrometry of volatile organohalogen compounds in drinking water.

The analysis of organic pollutants in drinking water is a topic of wide interest, reflecting on public health and life quality. Many different methodologies have been developed and are currently employed in this context, but they often require a time-consuming sample pre-treatment. This step affects the recovery of the highly volatile compounds. Trace analysis of volatile organic pollutants in water can be performed 'on-line' by membrane inlet mass spectrometry (MIMS). In MIMS, the sample is separated from the vacuum of the mass spectrometer by a thin polymeric hollow-fibre membrane. Gases and organic volatile compounds diffuse and concentrate from the sample into the hollow-fibre membrane, and from there into the mass spectrometer. The main advantages of the technique are that no pre-treatment of samples before analysis is needed and that it has fast response times and on-line monitoring capabilities. This paper reports the set-up of the analytical conditions for the analysis of volatile organohalogen compounds (chloroform, bromoform, bromodichloromethane, chlorodibromomethane, tetrachloroethylene, trichloroethylene, 1,1,1-trichloroethane, and carbon tetrachloride). Linearity of response, repeatability, detection limits, and spectra quality are evaluated.

Carbon Tetrachloride↗
PubMed1998

Gas exchange threshold as a predictor of severe postoperative complications after lung resection in mild-to-moderate chronic obstructive pulmonary disease.

Low exercise capacity is considered predictive for postoperative complications or death after thoracic and general surgery. However, in recent literature no agreement has been found about the predictive cut-off values for preoperative exercise parameters. The aim of this work was to investigate whether peak oxygen consumption (V'o2) and noninvasive anaerobic threshold (AT) determined by gas exchange threshold (GET) can be reliable preoperative predictors of mortality and morbidity after lung resection in patients with mild-to-moderate (forced expiratory volume in one second (FEV1) > 50% predicted) chronic obstructive pulmonary disease (COPD). Fifty tour COPD patients were studied before lung surgery: 12 had severe complications, 16 had mild and 26 had no complications. Peak V'O2 sensitivity and specificity in predicting severe postoperative complications were 41.6% and 95.5% respectively (using 75% of the predicted value as cut-off), while for GET they were 91.6% and 97.6% respectively (using 14.5 mL.kg-1.min-1 as cut-off value). Only one patient (3.5%) with a peak V'O2 > 20 mL.kg-1.min-1 suffered severe complications. On the other hand 11 out of the 26 patients (42.3%) with peak V'O2 < 20 mL.kg-1.min-1 had serve complications. In patients with peak V'O2 < 20 mL.kg-1.min-1, 11 out of 12 (91.6%) with a GET < or = 14.5 mL.kg-1.min-1 suffered severe complications, whereas 15 out of 15 (100%) with a GET > 14.5 mL.kg-1.min-1 showed no or mild complications. In conclusion, peak oxygen consumption values > 20 mL.kg-1.min-1 can be considered a safe upper cut-off limit for pulmonary resection. In patients with a peak oxygen consumption value < 20 mL.kg-1.min-1, gas exchange threshold determination can improve significantly the predictivity of a cardiopulmonary test for severe complications and must be routinely considered.

Adult↗
PubMed1995

Doppler echocardiographic patterns in patients with acromegaly.

Cardiovascular problems have long been recognized as responsible for an increased morbidity and mortality in patients with acromegaly. The aim of the present study was to evaluate echocardiographically the prevalence of cardiomyopathy in a cohort of acromegalic patients and to analyze the results in relation to demographic, clinical and hormonal data. This study, a retrospective controlled clinical trial, was performed in 25 acromegalic patients, 12 men and 13 women aged 26-66 years (mean: 52.6). Fifteen patients had an active disease, 10 were cured by previous pituitary surgery. The same echocardiographic parameters were analyzed in 50 healthy subjects aged 30-70 years (mean: 51.4). Serum GH was determined on at least 4 samples drawn over 24 hours and plasma IGF-I on a single point. Standardized parameters of diastolic and systolic function were evaluated by real-time Doppler echocardiography. Twelve patients with active acromegaly underwent also 48-hour ECG registering. Left ventricular (LV) hypertrophy was found in 14/25 patients (56%). No difference was found between patients with active disease (53%) and patients with cured acromegaly (60%). LV mass index was significantly increased in acromegalics in comparison with healthy subjects (137 +/- 43 g/m2 vs 96 +/- 16 g/m2, p < 0.01) and also the indices of LV diastolic function were significantly impaired. Asymmetric septal hypertrophy was found only in one patient. Hypertension was detected in 9/25 patients (36%) without difference between patients with active or cured disease (40% vs 30%, NS). No significant correlation was found between hormonal or clinical data and echocardiographic findings. During Holter monitoring, heart rate of acromegalics was not significantly different from that of controls (78 +/- 12 bpm vs 72 +/- 10 bpm, NS) and only isolated supraventricular or ventricular premature complexes (Lown class 1) were detected. In conclusion, this study provides evidence of subclinical LV dysfunction in acromegaly in the absence of other known causes of heart disease and no significant difference in echocardiographic pattern was apparent between active or cured acromegalics.

Acromegaly↗
PubMed1992

Endomyocardial biopsy of normal donor hearts before cardiac transplantation. A morphological and morphometrical study in 97 cases.

Endomyocardial biopsies from 97 normal donor hearts were examined. Morphometric analysis showed: mean myocyte diameter 22.21 +/- 6.93 mu, mean nuclear dimension 7.32 +/- 2.33 mu, mean nuclear/sarcoplasmic ratio 0.33 +/- 0.02. 31 biopsies showed enlarged myocytes (mean diameter 31.65 +/- 3.98 mu) with increased nuclear size (mean 10.45 +/- 1.39 mu), but preserved nuclear/sarcoplasmic ratio (mean 0.33 +/- 0.01). The mean age of these latter subjects was significantly higher. Endocardial thickness mean value was 17.73 +/- 4.58 mu, but in 28 cases the value exceeded the considered upper normal limit of 20 mu. Interstitial mononuclear cells were rare and randomly present. Interstitial fibrosis was observed in 15% and focal fibrosis in 27% of cases. Our results show that histology of biopsies from clinically normal hearts can widely vary, sometime overriding the pathologic boundaries. These apparently "benign" abnormalities should be kept in mind when specific pathologic substrates of cardiac diseases have to be defined.

Adolescent↗
PubMed1990

Expression of natriuretic peptide in ventricular myocardium of failing human hearts and its correlation with the severity of clinical and hemodynamic impairment.

Atrial natriuretic peptide (ANP) was immunohistochemically investigated in (1) right ventricular endomyocardial biopsy specimens from 87 apparently healthy donor hearts taken from victims of cerebral accidents; (2) 1 normal heart not suitable for transplantation (HBsAg carrier); (3) right ventricular endomyocardial biopsy specimens from 151 patients with dilated cardiomyopathy (DC); and (4) 57 explanted hearts, 26 with DC and 31 with ischemic heart disease. No ANP immunoreactivity was found in normal ventricles. Failing hearts showed ventricular positivity in 31% of the DC biopsy series, in 61% of the left ventricles, and in 30% of the right ventricles of the explanted heart series. An endoepicardial gradient was observed, because ANP positivity was greater and more extensive in the subendocardial layers. Ultrastructural studies were performed on biopsy specimens from 10 normal hearts and 132 DC biopsy samples. No ANP-storing granules were found in biopsy samples of normal ventricles, whereas ANP granules were seen in 15 of 132 (11.4%) DC cases. In parallel immunoblotting, investigation showed the same 13 kDa band protein in 1 normal atrium as well as in 8 failing atria and ventricles. ANP immunoreactivity was positively correlated with higher New York Heart Association functional classes as well as with higher left ventricular end-diastolic pressure (p less than 0.005), end-diastolic volume (p less than 0.005) and end-diastolic volume index (p less than 0.005). In conclusion, apparently healthy ventricles do not show ANP immunoreactivity, whereas failing ventricles do. ANP expression seems to be independent of the underlying disease, but positively related to the clinical status and the degree of left ventricular impairment and dilatation.

Adult↗
PubMed1989

The morphologic spectrum of dilated cardiomyopathy and its relation to immune-response genes.

Endomyocardial biopsies from 174 patients with dilated cardiomyopathy (DC) were examined. Eight patients with histologically proven myocarditis were excluded from the study. A peculiar pattern of oversized and bizarre nuclei was observed in only some of the remaining patients. Two groups were identified: those with and without this feature (groups A and B, respectively). Myocyte width, nuclear diameter and nuclear/sarcoplasmic ratio were significantly higher in group A. The mean respective values were 36 +/- 5 mu, 14 +/- 3 mu and 0.41 +/- 0.08 for group A versus 20 +/- 8 mu, 7 +/- 2 mu and 0.37 +/- 0.08 for group B. Interstitial fibrosis was similarly present in groups A and B. Endocardial thickness was significantly increased in all patients, with group A showing the highest mean value. The morphologic features showed no correlation with the clinical condition of the patients at time of presentation. HLA typing was performed in 50 consecutive patients, 38 from group A and 12 from group B. DR4 and DR5 antigens were significantly more frequent in DC patients than in a normal population control (400 blood donors), while DR3 was less frequent. Group A was more strongly associated with the DR5 antigen than group B (55.3 vs 25.0%, respectively). It was less strongly associated with the DR4 antigen compared with group B (21.5 vs 41.7%, respectively). No difference was observed between the 2 groups concerning negative association with the DR3 antigen. Endomyocardial biopsies from DC patients reveal marked morphologic changes from patient to patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Progressive changes in the lymphocyte subpopulations and the clinical picture in 2 brothers with familial dilated cardiomyopathy].

We report two brothers, aged 22 and 34, affected by dilated cardiomyopathy. At the first examination both patients were in NYHA functional class I. Their echocardiograms showed dilated and hypokinetic ventricles. Their clinical condition remained stable for three years, during which the peripheral immunophenotyping of T-lymphocyte subsets showed T-helper/T-suppressor ratio values lower than normal (normal value for our laboratory = 1.64 +/- 0.53) due both to low T-helper and to high T-suppressor subsets. Subsequently, the clinical condition of both patients deteriorated, exercise tolerance decreased and echocardiographic ventricular diameters increased. T-helper/T-suppressor ratio progressively increased from the initial values of 0.8 and 0.42 to 2.5 and 2.24, respectively. A few months later, both patients died, one because of refractory heart failure and the other one suddenly. Histologic examination of myocardial tissue in one patient showed a diffuse necrotizing disease involving myocytes with focal lymphocyte infiltrates, granulation tissue and endocardial thrombosis. The reported data underline the importance of genetic and familial factors in the pathogenesis and evolution of dilated cardiomyopathies. The increasing T-helper/T-suppressor ratio value which matched the deterioration of the clinical status, is proposed as a useful evolutive and prognostic marker.

Adult↗
PubMed1988

Ultrafiltration in the treatment of refractory congestive heart failure.

Artificial subtraction of fluids and solutes was evaluated in the course of acute and chronic heart failure when it became refractory to standard intensive medical treatment. A group of 19 patients (mean age 57 years), 9 with ischemic, 2 amyloidotic, 4 valvular, and 4 idiopathic cardiomyopathy, were treated. In 17 patients extracorporeal ultrafiltration (UF) by means of a polysulfonate ultrafilter was adopted along 125 sessions (105 assisted by a roller pump and 20 as a slow continuous ultrafiltrate). In two patients continuous peritoneal dialysis was adopted. In every case UF was well tolerated. Ultrafiltrate volumes ranged from 1680 to 3500 ml for every session with corresponding Na losses ranging from 194 to 434 mEq/session. Improved clinical and functional status with reduction of edema was observed in 17 of 19 patients. In 12 patients UF could be discontinued due to restored response to diuretics; 5 of these patients could subsequently undergo heart surgery (1 transplant, 3 valve replacement, 1 coronary bypass). The remaining 7 patients survived on medical therapy alone for an average of 228 days. In 7 of 19 cases, UF could not be discontinued, and these patients died after an average of 23 days of treatment. In conclusion, UF proved to be effective in eliminating salt-fluid overload and restoring response to medical treatment. Patients who are potential surgical candidates seem to be the most suitable for UF.

Adult↗
PubMed1987

[Lymphocyte subpopulations in idiopathic dilatational cardiomyopathy].

Lymphocyte subsets have been examined in 23 patients affected by idiopathic dilated cardiomyopathy (IDCM). Patients were divided according to their functional class showing that compromised subjects exhibited high T-lymphocyte helper/suppressor ratio whereas the contrary was observed in the other patients. It has therefore suggested that IDCM is characterized by 2 distinct phases, each of them with different helper/suppressor ratio.

Adult↗
PubMed1986

[Aneurysm of the sinus of Valsalva and late rupture of the interventricular septum due to infective endocarditis. Is the two-dimensional echocardiography of endocarditic extension into the interventricular septum possible?].

In a 54 year old woman affected by infective endocarditis, with bicuspid aortic valve and aneurysm of sinus of Valsalva protruding into the right atrium, two-dimensional echocardiography helped to identify altered myocardial echo patterns of the interventricular septum at basal level. Because of the proximity with valvular lesions due to endocarditis, we could interpret these appearances as produced by invasion of the infective process into the septum. The autopsy report of septum rupture in the same area further supports our interpretation of the echocardiographic finding.

Aortic Aneurysm↗