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Biomedical subjects

R Sala

Publications and source records attributed to R Sala.

At least 55 records · Page 3Linked to original sources
PubMed1997

Telehealth in Africa.

This paper deals with the developments of the project "Telehealth in Africa", to establish a link between more European reference Hospital Centers and some African Hospital Centers, connected with Peripheral Units of Assistance, to transmit and receive health diagnostic images, etc. The project has been developed by the European Collaboration Group for Telemedicine in developing countries which was created in collaboration with ITU (International Telecommunication Union). A demonstration of telehealth from Milan (Italy), Toulouse (France), to Abidjan (Ivory Coast, Africa) and Midrand (South Africa) proves that it is possible for a diverse group of intergovernmental organizations, non-governmental organizations and the private sector to work together for the benefit of all participants and, most of all, for developing countries.

Africa↗
PubMed1997

Telerobotic surgery: applications on human patients and training with virtual reality.

This paper deals with the developed researches and applications on telerobotic surgery, devoted to human patients and with training by virtual reality. The researches have been developed in cooperation between Telerobotics Laboratory, Department of Mechanics, Politecnico di Milano, Italy, and Automation and Control Section, Jet Propulsion Laboratory, Pasadena, USA. The researches carried to a telesurgery robotic operation on a dummy on 7th July 1993, by means of satellites communications, to a prostatic biopsy on a human patient on 1st September 1995 with optical fibers, to results on time delay effects, to results on virtual reality applications for training on laparoscopy and surgery. The search implied time delay when the control input originated in Politecnico di Milano, Italy. The results were satisfactory, but also pointed out the need for specific new control transformations to ease the operator's or surgeon's visual/mental workload for hand-eye coordination. In the same research, dummy force commands from JPL to Milan were sent, and were echoed immediately back to JPL, measuring the round-trip time of the command signal. This, to some degree, simulates a contact force feedback situation. The results were very surprising; despite the fact that the ISDN calls are closed and "private" calls, the round-trip time exhibited great variations not only between calls but also within the same call. The results proved that telerobotics and telecontrol may be applied to surgery. Time latency variations are caused by features of communication network, of sending and receiving end computer software. The problem and its solution is also an architectural issue, and considerable improvements are possible. Virtual reality in the application of the research is a strong support to training on virtual objects and not on living beings.

General Surgery↗
PubMed1996

[In vitro effect of heroin on neutrophil polymorphonuclear leukocytes from peripheral blood].

BACKGROUND: Infections are the most common medical complications in drug addicts. Some studies suggest that heroin itself could facilitate them by altering the polymorphonuclear leukocyte (PMNL) function of these patients. The aim of this study was to analyze the heroin effect on the chemotaxis, the phagocytosis and the bactericidal oxidative metabolic activity on PMNL from 10 healthy adults. MATERIAL AND METHODS: Three samples of 20 ml of blood were obtained from each donor, separating the leukocytes later. The first sample was used as control (A group); heroin was added to the blood of the second sample before PMNL separation (1 mg of heroin into 20 ml of blood)(B group) and to the third sample after PMNL separation (0.05 mg of heroin in 1 ml of PMNL suspension)(C group). The concentration of heroin used was 50 microliters/ml of blood (this concentration was higher than the lethal concentration found in the blood of drug addicts who die from heroin overdose). The PMNL functions studied in vitro were the chemotaxis of PMNL applying the under agarosa gel method, and for the phagocytosis and the intracellular oxidative metabolic activity the following two tests were used: the ingestion of bacto-latex particles combined with nitroblue tetrazolium (NBT) reduction test and the chemoluminiscence method. The statistical analysis was done using parametric and non-parametric tests. RESULTS: There were no differences between the three groups studied (A, B or C) regarding chemotaxis, the ingestion of bacto-latex particles and the NBT reduction test. Concerning chemoluminiscence, it was inferior in the C group (with PMNL directly incubated with heroin) compared with A group (control) and B group (with PMNL from blood with heroin)(p < 0.05). However, there were no statistically significant differences between A and B groups. CONCLUSIONS: In this study, heroin did not have any in vitro significative effect of chemotaxis, phagocytosis and oxidative metabolic activity on the human PMNL.

Adult↗
PubMed1996

Acute myocardial infarction in humans is associated with activation of programmed myocyte cell death in the surviving portion of the heart.

Conditions of diastolic overload associated with increases in filling pressure trigger apoptosis. Moreover, ischemia alone and ischemia followed by reperfusion induce programmed cell death in myocytes in vitro. On this basis, the possibility was raised that apoptotic myocyte cell death may occur in the surviving myocardium acutely after infarction. Myocardial samples were obtained from the region adjacent to and remote from infarction in patients who died within 10 days from the initial clinical symptoms. Apoptosis was measured quantitatively by the terminal deoxynucleotidyl transferase assay and confirmed biochemically by DNA extraction and agarose gel electrophoresis. This analysis included 20 infarcted and ten control hearts. DNA strand breaks in myocyte nuclei were observed in all 20 infarcted hearts in both the regions bordering on and distant from the necrotic myocardium. However, the number of apoptotic nuclei was greater in the peri-infarcted region than in that away from infarction. Quantitatively, 12% of myocytes in the border zone showed DNA strand breaks, whereas 1% of cells were undergoing apoptosis in the remote myocardium. Moreover DNA laddering was detected biochemically in these two regions of the heart. Thus, apoptosis appears to be a significant complicating factor of acute myocardial infarction increasing the magnitude of myocyte cell death associated with coronary artery occlusion.

Adult↗
PubMed1995

Lower Pleistocene hominids and artifacts from Atapuerca-TD6 (Spain)

Human remains dating to more than 780,000 years ago are associated with a rich faunal and lithic assemblage in the Pleistocene cave site of Gran Dolina (TD), Sierra de Atapuerca, Burgos, Spain. The micromammal species represent the late Biharian (Mimomys savini zone), and the lithic objects represent pre-Acheulean technology (Mode 1) and comes from the TD6 level below the Matuyama-Brunhes boundary. The Gran Dolina hominid fossils cannot be comfortably accommodated in any of the defined Homo species. They could be considered a primitive form of Homo heidelbergensis, but a new species might be named in the future if the sample is enlarged. The new human fossil evidence demonstrates that Western Europe was settled at least since the late early Pleistocene.

Animals↗
PubMed1995

Execution of robot-assisted biopsies within the clinical context.

This paper describes the first prostatic biopsy on a human patient using a robotic and telerobotic system. This system was designed at the Politecnico di Milano, and the biopsy was performed on April 7, 1995, in the Hospital Policlinico in Milan, Italy.

Biopsy, Needle↗
PubMed1993

Histopathological events throughout the development of turbot (Scophthalmus maximus L.) larvae.

Histopathological observations in cultured turbot (Scopthalmus maximus L.) larvae are described in varying developmental stages. No striking changes were found during the endogenous feeding period. After the introduction of live food, the main lesions encountered were atrophy and degeneration of the digestive system, but these lesions were not associated with high mortality rates in the culture system during the early stages. Subsequently, during the stages of organogenesis, progressive bacterial colonization of the digestive tract was observed, accompanied by severe enteritis, especially in the more mature larvae. High mortality rates were detected in the rearing system at this time. In severe cases, necrosis of pancreatic acini and hepatocytes were observed also. Swimbladder alterations such as non-inflation, malformation and bacterial invasion via the pneumatic duct were frequently observed at all stages of development. It is suggested that infectious agents may play an important role in the high mortality often encountered in cultured turbot larvae.

Air Sacs↗
PubMed1993

Characterization of amino acid transport in human endothelial cells.

The transport of amino acids has been studied in human umbilical vein endothelial cells. Neutral amino acids enter human umbilical vein endothelial cells through three distinct agencies endowed with the characteristics of systems A, ASC, and L. Each system has been studied by evaluating the influx of preferential substrates. The influx of L-proline and 2-methylaminoisobutyric acid occurs through an Na(+)-dependent adaptively regulated trans-inhibited agency identifiable with system A. L-Threonine influx occurs mainly through a distinct Na(+)-dependent trans-stimulated pathway corresponding to system ASC. System L accounts for Na(+)-independent influx of L-leucine. These systems cooperate for the transport of L-glutamine, which is due mainly to system ASC, whereas the component due to the operation of system A increases upon amino acid starvation. No clear evidence was found for a glutamine-specific system ("system N"). Two systems, one Na+ dependent (system XAG-) and the other Na+ independent (system xc-), transport anionic amino acids. L-Arginine influx exhibits a poor dependence on extracellular Na+, whereas it is sensitive to conditions known to change membrane potential and to trans-stimulation by intracellular amino acids. These features are consistent with a process mediated by system y+ and may be of significance for the regulation of the intracellular concentration of L-arginine.

Amino Acids↗
PubMed1993

Maternal diabetes induces increased expression of extracellular matrix components in rat embryos.

The mechanisms responsible for the increased incidence of congenital malformations in offspring of diabetic mothers are poorly understood. Because the abnormal metabolic milieu of diabetes induces in the adult organism increased synthesis of basement membrane components, and these molecules play a prominent role in morphogenesis, we investigated whether maternal diabetes or high glucose levels disturb extracellular matrix synthesis in rat embryos. In gestational day 11 embryos, maternal diabetes induced a small but significant increase in laminin B1 (127 +/- 40% of control, mean +/- SD, P < 0.02) but not in fibronectin mRNA (101 +/- 26% of control). Day 12 embryos from diabetic mothers showed a larger increment in laminin B1 (179 +/- 91% of control, P < 0.02) and also an increase in fibronectin mRNA (172 +/- 73% of control, P < 0.02). A similar increase in the expression of fibronectin was observed in the kidneys and hearts of day 20 fetuses dissected from diabetic rats. High glucose levels mimicked in vitro the effects of maternal diabetes. Day 9 embryos cultured for 48 h in 50 mM D-glucose showed, akin to the day 11 embryos in vivo, an increase in laminin B1 mRNA (129 +/- 47% of control) and no changes in fibronectin mRNA (106 +/- 35% of control). The finding that maternal diabetes induces increased expression of extracellular matrix components in developing embryos establishes a link with the abnormalities occurring in the chronic complications of diabetes and proposes a new path of investigation for the mechanism of teratogenicity of the diabetic milieu.

Animals↗
PubMed1993

Protection by N-acetylcysteine against pulmonary endothelial cell damage induced by oxidant injury.

The protective effect of N-acetylcysteine (NAC) against oxidant lung injury was investigated in a model of acute immunological alveolitis in the rat. Intrapulmonary immune complex deposition into rat lungs, induced by intratracheal infusion of immunoglobulin G (IgG) anti-bovine serum albumin (BSA) antibodies and intravenous injection of the antigen, caused lung damage associated with a marked decrease in [14C]5-hydroxytryptamine ([14C]5HT) uptake capacity, taken as a biochemical marker of endothelial cell function. The oral administration of a single dose of NAC (2 mmol.kg-1) 60 min before antigen/antibody (Ag/Ab) treatment was effective in preventing pulmonary endothelial cell [14C]5HT uptake loss induced by immune complex deposition. The mechanisms involved in this lung protective action of NAC were investigated by studying the antioxidant activity of NAC on hypoxanthine/xanthine oxidase-induced lung damage in vitro, and the effectiveness of the drug as lung glutathione (reduced form) (GSH) precursor in diethylmaleate-depleted rats. The results obtained provide further evidence on the ability of NAC to reduce the susceptibility of lung tissue to free radical-induced damage, by potentiating the antioxidant defence systems.

Acetylcysteine↗
PubMed1991

The specific binding of broxaterol, a new beta 2-selective agonist, to beta-adrenoceptors.

The specific binding of broxaterol, a potent new orally active antiasthmatic drug, to beta 1- and beta 2-adrenoceptors was characterized by receptor binding studies with rat heart and lung membrane preparations. Broxaterol showed high affinity and selectivity for the beta 2-component of [3H]dihydroalprenolol binding in both lung (58% beta 2-sites, Ki = 130 nM) and heart membranes (19% beta 2-sites, Ki = 98 nM), whereas the binding to the beta 1-component was at lower affinity (42% beta 1-sites, Ki = 4100 nM in the lung and 81% beta 1-sites, Ki = 3460 mM in the heart). The influence of temperature changes on the binding properties of broxaterol towards beta-adrenoceptors was also investigated. A marked increase in the affinity of broxaterol for lung beta-receptors was observed on lowering the assay temperature, whereas the affinity for heart beta-receptors was little affected by temperature changes. Thermodynamic analysis of the binding data showed that the binding of broxaterol as well as isoproterenol to lung beta-receptors was associated with a large decrease in enthalpy, which correlates well with the full agonistic properties of this compound at beta 2-receptors.

Adrenergic beta-Agonists↗
PubMed1990

Overexpression of fibronectin induced by diabetes or high glucose: phenomenon with a memory.

To identify events and mechanisms that might contribute to the poor reversibility of diabetic complications, we examined whether diabetes or high glucose induces changes in gene expression and whether such changes outlast the presence of the metabolic abnormalities. The study focused on fibronectin because the increased amounts of this glycoprotein found in diabetic tissues and thickened basement membranes are as yet unexplained. In streptozotocin-induced diabetic rats, fibronectin mRNA levels were increased to 304 +/- 295% of control (mean +/- SD) in the kidney cortex (P less than 0.02), and to 271 +/- 273% of control in the heart (P less than 0.02), while actin mRNA levels remained unchanged. Elevation of fibronectin mRNA persisted for weeks after restoration of near-normoglycemia. In cultured human endothelial cells, high glucose-induced overexpression of fibronectin and collagen IV remained detectable after replating and multiple cell divisions in the absence of high glucose. Cells shifted to normal-glucose medium after prolonged exposure to high glucose also exhibited a proliferative advantage over cells chronically maintained in normal glucose. Thus, diabetes increases fibronectin expression in tissues that are known targets of the complications, and the effect is not readily reversible. The in vitro studies suggest that hyperglycemia may be responsible for these events through induction of self-perpetuating changes in gene expression.

Animals↗
PubMed1990

Effects of tilt and exercise on signal-averaged electrocardiogram after acute myocardial infarction.

To determine whether enhanced sympathetic activity could alter a non-invasive index of cardiac instability, we analysed the effects of 90 degrees head-up tilt and submaximal exercise stress test on high amplification signal-averaged electrocardiogram in 64 patients after acute myocardial infarction. At rest, ventricular late potentials were detected in 25% of patients, characterized by a significant prolongation of filtered QRS complex (137 +/- 3 vs 115 +/- 2 ms) and of its components smaller than 40 microV (38 +/- 2 vs 16 +/- 1 ms), as well as by a reduced root mean square voltage calculated for the terminal 40 ms of QRS complex (RMS40 voltage) (19 +/- 1 vs 75 +/- 9 microV) in comparison to patients without micropotentials. Sympathetic activation induced by tilt caused a significant increase in heart rate (from 67 +/- 3 to 79 +/- 3 beats min-1) but did not modify either the incidence of ventricular late potentials or the values of any of the signal-averaged electrocardiogram parameters considered. In 19 patients, recordings were also obtained during a submaximal bicycle exercise stress test at a heart rate of 114 +/- 4 beats min-1 and with systolic arterial blood pressure at 153 +/- 6 mmHg. No effect on signal-averaged electrocardiogram parameters was detectable during this experimental intervention. These data indicate that after myocardial infarction, sympathetic activation does not seem to modify signal-averaged electrocardiogram parameters.

Electrocardiography↗
PubMed1990

[Echo-Doppler study of myxomatous mitral valve insufficiency and the results of reparative surgery].

The aim of conservative management of mitral regurgitation caused by floppy mitral valve is to restore a valvular function which closely resembles that of normal physiology. Fifty-eight patients affected by floppy mitral valve underwent surgical procedures for severe mitral regurgitation due to chordal elongation and/or rupture. Of these, 28 presented posterior mitral prolapse corrected by quadrangular excision of the prolapsed part and posterior anuloplasty achieved by apposition of a polytetrafluoroethylene conduit. The remaining 30 patients presented anterior or bilateral prolapse corrected by transposition of chordae from the posterior leaflet to the anterior cusp together together with anuloplasty. A complete echo-Doppler study was performed preoperatively, 10 days after the operation and every 6 months thereafter. Mean follow-up was 16.1 +/- 6.3 months. Preoperatively, 44 patients presented severe mitral regurgitation and 14 had moderate regurgitation (quantified by means of pulsed Doppler). All patients showed severe enlargement of the left cavities (LVDD 67.1 +/- 8.6 mm, left atrium 53.4 +/- 10.9 mm) with normal mitral area (6.08 +/- 2.14 sqcm, Doppler measurement). Following surgery we found a significant reduction in: 1) the degree of mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgition, confirmed by color-M-mode; moderate or severe regurgitation was found in 6 cases); 2) the left ventricle and left atrium dimensions (LVDD 53.4 +/- 5.2 mm, p less than 0.01; left atrium 43.8 +/- 11.1 mm, p less than 0.01). Color flow imaging provided information about the recovery of a normal valvular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography, Doppler↗
PubMed1989

New isoxazole derivatives provided with antihypertensive activity.

A series of diazacycloalkane-quinazoline derivatives of isoxazoles were synthesized and tested in order to identify new potent and selective alpha 1-antagonists. A preliminary screening by using in vitro tests such as binding assay (3H-prazosin and 3H-rauwolscine displacement) and analysis of antagonistic activity in isolated rat aorta (norepinephrine-induced response) and in isolated rat vas deferens (clonidine-induced response) indicated that many of these compounds exhibited a good affinity and selectivity towards alpha 1-adrenergic receptors associated with potent pharmacological activity. In particular, a 3-bromo-5-isoxazolecarbonyl derivative, selected for further in vivo investigation, was provided with as high antihypertensive action as prazosin in spontaneously hypertensive rats (SHR) coupled to a shallow dose-response curve by oral route. Moreover, a higher ratio between oral antihypertensive doses in SHR and normotensive rats was found with respect to reference compound prazosin.

Animals↗