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Biomedical subjects

G Torri

Publications and source records attributed to G Torri.

At least 109 records · Page 6Linked to original sources
PubMed1997

Synthesis and biological effects of N-alkylamine-labeled low-molecular-mass dermatan sulfate.

Dermatan sulfate (DS) is a component of connective tissue and catalyzes the heparin cofactor II-mediated inhibition of thrombin. Low-molecular-mass dermatan sulfates (LMMDS) are produced to prolong the antithrombotic activity of this substance. Cleavage of DS by nitrous acid leads to an LMMDS with a terminal 2,5-anhydrotalose (At) group at the reducing end which can react with primary amines. Tyramine (Tyr) was bound to the terminal At of LMMDS using reductive amination. LMMDS-tyr is produced using DS. LMMDS desacetglated were produced using totally deaminated DS. These compounds were employed as a model for the characterization of DS using NMR spectroscopy. The purity of the compounds was checked using capillary electrophoresis. The structure of the products was proven by 1H- and 13C-NMR spectroscopy. LMMDS-Tyr was radiolabeled with 125I for use in a radioimmunoassay. The anti-Xa activity and antithrombin activity of the tyramine-labeled DS are very low. The clotting assays Heptest, aPTT, thrombin time, and ecarin time indicate a highly anticoagulant-active substance. The heparin cofactor II-mediated inhibition of thrombin is similar to the parent compound. LMMDS were labeled "endpoint-attached." They are a new tool to understand the actions of DS in biologic systems.

Animals↗
PubMed1997

Cardiorespiratory changes during gynaecological laparoscopy by abdominal wall elevation: comparison with carbon dioxide pneumoperitoneum.

We have studied the cardiorespiratory changes produced by abdominal wall elevation (AWE) or carbon dioxide pneumoperitoneum (PN) in 20 women undergoing gynaecological laparoscopy. Arterial pressure, heart rate, lung/chest complicance and blood-gas tensions were measured 10 min after induction of general anaesthesia (T0), 10 min after abdominal distension in the supine position (T1) and 10 min after the Trendelenburg position was assumed (T2). Visual analogue scores for pain were recorded 1 and 6 h after the end of surgery. We found that lung/chest compliance was reduced significantly in group PN at T1 and T2 compared with both T0 and group AWE. Diastolic arterial pressure increased significantly in group PN at T1 and T2 compared with both T0 and group AWE, while it remained unchanged in group AWE. Arterial PCO2 increased significantly only in group PN after pneumoperitoneum, while oxygenation was almost unchanged in both groups. AWE patients had greater abdominal pain 1 h after surgery. Six hours after surgery pain was similar in the two groups. These data indicate that abdominal wall elevation reduced pulmonary compliance less than a pneumoperitoneum in patients undergoing gynaecological laparoscopy.

Abdominal Muscles↗
PubMed1997

Arterial to end-tidal carbon dioxide gradient and physiological dead space monitoring during general anaesthesia: effects of patients' position.

METHODS: One hundred and five ASA I-II patients, scheduled for elective surgical procedures were studied in order to evaluate the effect of different surgical postures on physiological pulmonary dead space (VDphys/ VT) and arterial to end-tidal carbon dioxide gradient [P(a-Et)CO2]. Patients were divided into four groups according to their position on the operating table: supine position (acting as control group, n = 33), 20 degree Trendelenburg position (n = 24), lateral position (n = 24) and prone position with convex saddle frame (n = 24). Physiologic dead space was measured using Enghoff modification of Bohr equation. Arterial CO2 partial pressure was measured by blood gas analysis and end tidal CO2 was measured by means of an infrared CO2 analyser. All measurements were performed 20 minutes after general anaesthesia induction, with patients mechanically ventilated by a constant inspiratory flow (TV = 8 ml kg-1, RR = 10-14, EIP = 10%) in order to reach a steady state end tidal CO2 ranging between 32 and 36 mmHg; afterwards surgery started. RESULTS: Arterial blood pressure showed a mean decrease of about 5-10% compared to baseline values, but no significant differences in arterial pressure decrease were found between the four groups. A significant VDphys/VT increase in postures other than supine was observed, unless it was statistically significant in lateral and prone position only; while P(a-Et)CO2 was higher in all postures compared to supine. Changes of intrapulmonary gas and blood distribution due to patients' posture are probably responsible for the observed physiologic dead space and CO2 gradient differences. CONCLUSIONS: In conclusion, the clinical practice of predicting PaCO2 from EtCO2 must be tempered by recognition of the potential magnitude of P(a-Et)CO2 gradient, which is higher than normal during general anaesthesia and further increased when positioning the patient other than supine.

Adult↗
PubMed1997

[Interaction of soda lime and halogenated anesthetics].

The increased use of soda lime for low flow anaesthesia leads to some problems related to the interaction with halogenated agents. These agents may be absorbed by soda lime or degradated according to their water content. Halothane and enflurane, in contact with soda lime, produce some metabolites, but their concentration is low when compared to their own lethal concentration. Sevoflurane degradates to four compounds. Compound A may reach a value between 13.3-42.1 ppm in the inspired fraction: these values are 50-100 times lower than the toxic concentrations. Isoflurane and desflurane are degradable at very low extent. Some case reports of unexpected high carboxyhemoglobin levels during anaesthesia indicate the possibility of CO production from soda lime and baralyme when halogenated agents are used. This reaction occurs only with anaesthetics containing CHF2-moiety (isoflurane, enflurane and desflurane) and when some specific factors make soda lime or baralyme completely dry. Low flow anaesthesia preserves the moisture content of the soda lime and protects from carbon monoxide production, by increasing water content in the circle.

Absorption↗
PubMed1997

[Perioperative thermal homeostasis. A duty of the anesthesiologist].

Anaesthesia, surgical procedures and operating room temperature can deeply alter the human thermoregulatory system. Unexpected and sometimes serious perioperative complications can occur. Many studies have been carried out in order to describe and evaluate the detrimental effects produced by different anaesthesia procedures (whether by general, regional or integrated anaesthesia) on thermic homeostasis. More recently it has also been reported that perioperative hypothermia significantly affects patients' outcome, increasing intraoperative blood losses, incidence of postoperative wound infection, and hospital stay. Italian anaesthetists have still a poor consideration about intraoperative body temperature monitoring and patients' warming as basic important skills for a better anaesthesiologic patients management. According with the literature, we do believe that this is not a right opinion. The purpose of the present paper would be to point out the most important knowledges concerning thermic homeostasis management, in order to increase anaesthesiologist's awareness in this essential field of patients perioperative care.

Anesthesia↗
PubMed1997

Treatment of severe acidemia in a young woman affected by diabetic ketoacidosis.

The case of a 32-year-old woman admitted to Hospital for diabetic coma (GCS 8), with arterial blood pH below usually reported vital range, is described. After First Aid admittance an arterial blood gas analysis adjusted for patient's temperature showed PaO2 10.77 kPa, PaCO2 7.8 kPa, pH 6.52, HCO3 5 mmol/L, BE-34.9. A significant increase of lactate and butyrate concentration was also found. The patient was intubated and breathing was assisted for a 60 hour period after ICU admission, while acidemia was treated by THAM and bicarbonate associated to potassium i.v. infusion (infusions were titrated on acid-base and electrolyte concentration direct monitoring). After progressive neurological and biochemical improvement, 7 days after ICU admission the patient was moved to an Internal Medicine department. This case demonstrated that during diabetic ketoacidosis, despite very low pH (below reported vital range), an invasive intensive treatment could give complete cure without neurological sequelae.

Adult↗
PubMed1996

1H and 13C NMR spectral assignments of the major sequences of twelve systematically modified heparin derivatives.

The complete 1H and 13C NMR spectral assignments are described for the most prevalent patterns of sulfation and acetylation which can be found in polymeric heparin or can be obtained by standard chemical modifications. These include a number of novel structures containing unsubstituted or acetylated amino groups and the first complete NMR assignments of many of the other derivatives. Beef lung heparin was chosen as a model system and studies were carried out using conditions to control the influences on the chemical shift positions in heparin samples of divalent cations and variations in pH and temperature.

Acetylation↗
PubMed1996

Hyperacute pneumonitis in a patient with overwhelming Strongyloides stercoralis infection.

The case of a 64-year-old man who was admitted to hospital with fever, general deterioration and anorexia is reported. For the past 4 years, the patient had been receiving corticosteroid therapy for a chronic inflammatory demyelinating polyradiculoneuropathy. Soon after admission the patient developed respiratory insufficiency as a result of a massive pneumonitis, with severe hypoxia, acute anaemia, acute renal failure and a systemic inflammatory response syndrome (SIRS) requiring admission to the Intensive Care Unit (ICU). All faecal, bronchial, duodenal and urine samples showed Strongyloides stercoralis larvae. Despite antihelmintic therapy and cardiorespiratory support, the patient died from the consequences of irreversible shock. Strongyloidiasis is present worldwide and can be a chronic, essentially asymptomatic infection. This nematode can produce an overwhelming hyperinfection syndrome, especially in patients showing deficient cell-mediated immunity. Strongyloides hyperinfection syndrome is frequently fatal but is potentially a treatable clinical condition. Patients undergoing immunosuppressive therapy or with suspected immunity deficiency (HIV infection, malnutrition, lymphomas, leukaemias or other neoplasia treated with systemic radiotherapy or chemotherapy) must be also monitored for opportunistic Strongyloides stercoralis infection, because clinical manifestation of the systemic hyperinfection syndrome can be rather non-specific.

Animals↗
PubMed1996

HPLC of structural isomers with cyclodextrin-poly(vinylamine)-coated silica columns, Part I: Synthesis and characterization of cyclodextrin-bonded stationary phases by NMR solid state.

Different supports for high-performance liquid chromatography are prepared by using the coating technology. These supports are based on silica beads coated with a beta-cyclodextrin-containing poly(vinylamine). Surface area, pore size distribution, and solid-state nuclear magnetic resonance are used for the characterization of these supports. The two different methods of preparation used lead to different arrangements of the polymer layers; hence, the supports have different mobility, rigidity, and accessibility of the cyclodextrin ring.

Carbon Isotopes↗
PubMed1996

Results of the representative Italian national survey on radon indoors.

A representative national survey on population exposure to radon in Italian dwellings was carried out from 1989 to 1994, with the co-operation of the National Health Service. The measurements were performed by 19 Regional Laboratories, all using the same techniques and protocols. A stratified, two-stage sampling procedure was used to sample families. The sampled families were approached door-to-door to maximize response. To optimize the quality of the measurements, two dosimeters, each containing two alpha track detectors, were placed together in one room (typically the bedroom) for two consecutive 6-mo periods. The distribution of annual radon concentration was derived from measurements in 4,866 dwellings. The average value is 75 Bq m(-3) and the fractions of dwellings above the reference levels of 150, 200, 400, and 600 Bq m-3 are 8.7%, 4.7%, 1.0%, and 0.2%, respectively. The geometric mean is 57 Bq m-3 while the geometric standard deviation is 2.0. The average values in the Italian Regions fall within the 20-120 Bq m-3 range. When the average radon concentration is examined vs. story, building materials seem to play a significant role. The average lifetime risk of lung cancer for chronic radon exposure of Italian population at home would be about 5 x 10(-3), using the risk factor proposed by the ICRP in 1993.

Air Pollutants, Radioactive↗
PubMed1996

Characterization of sulfation patterns of beef and pig mucosal heparins by nuclear magnetic resonance spectroscopy.

Though differing only slightly in their degrees of sulfation, heparin preparations from pig mucosa and those from beef mucosa have consistently different 13C- and 1H-NMR spectra, which provide useful fingerprints for distinguishing the two types of heparin. Integrated areas of NMR signals associated with minor, undersulfated sequences (assigned by comparison with mono-dimensional spectra of selectively desulfated heparins and by analysis of two-dimensional spectra of heparins prepared from pig and beef mucosa) permit quantitation of differences in sulfation patterns. Undersulfation of pig mucosal heparins at position 6 of the hexosamine units, determined by 13C-NMR and expressed as percent glucosamines nonsulfated at C6 referred to total glucosamines, is substantially lower for pig mucosal heparins than for beef mucosal heparins (16.9-21.7% vs 36.7-40.7%; average values: 18.6% vs 40.3%). By contrast, undersulfation at position 2 of the iduronic acid units, determined by 1H-NMR and expressed as percent nonsulfated iduronic acid referred to total (sulfated + nonsulfated) iduronic acid is significantly higher for pig mucosal preparations (9.6-13.5% vs 2.1-2.7%; average values: 12.7% vs 2.3%). Pig mucosal heparins also have a significantly higher content of 3-O-sulfated glucosamine units, which are markers for the active site of heparin for antithrombin-III.

Animals↗
PubMed1995

Optimization and comparison of three different methods for the determination of Rn-222 in water.

Three different systems for the determination of radon in water have been examined: liquid scintillation counting (LSC), degassification followed by Lucas cell counting (LCC) and gamma counting (GC). Particular care has been devoted to the sampling methodologies of the water. Comparative results for several environmental samples are given. A critical evaluation is also given on the basis of the final aim of the measurements.

Radon↗
PubMed1995

Conformational analysis of heparin epoxide in aqueous solution. An NMR relaxation study.

1H and 13C NMR relaxation measurements at various magnetic fields have been used to characterize the nature of overall and internal motions in heparin epoxide in aqueous solution. A two-dimensional homonuclear NOESY experiment showed a considerable number of cross-relaxing protons in the molecule. The inter-proton distances calculated from NOE data were compared with those obtained by molecular mechanics calculations. Several discrepancies between the experimental and the theoretical inter-proton distances as well as the variations in 13C spin-lattice relaxation times, measured at two magnetic fields, indicated that the polysaccharide tumbles anisotropically in solution. The rates of overall and internal motions as well as the order parameters have been calculated using a model-free spectral density function. The numerical values indicate that the correlation times which characterize overall molecular motion are outside the extreme narrowing limit (tau parallel = 8 x 10(-10) s and tau perpendicular = 4.2 x 10(-8) s) and that internal motion correlation time is on a picosecond timescale.

Carbohydrate Conformation↗
PubMed1995

Magnetic bead protamine-linked microtiter assay for detection of heparin using iodinated low-molecular-mass heparin-tyramine.

We have developed a competitive heparin binding assay employing protamine-coated magnetic beads for detection and measurement of heparin. The assay utilizes 125-iodine specifically bound to newly synthesized low-molecular-mass (LMM) heparin-tyramine. The tracer was stable over a period of 3 weeks, as demonstrated by gel filtration chromatography. The protamine-coated beads were found to be stable over at least two months. The heparin-tyramine bead assay had in buffer a lower detection limit of 0.04 microgram/ml and in plasma of 0.23 microgram heparin/ml. 50% binding was obtained at 0.7 microgram/ml and 20% binding at 4 micrograms/ml in plasma. The within assay coefficient of variation ranged from 9 to 28% for unfractionated, high molecular mass (HMM) heparin and from 12 to 15% for LMM-heparins in buffer system and in plasma. Various heparin fractions displaced the tracer from the protamine-coated magnetic beads to different extents. The validity of the assay was proven after intravenous administration of unfractionated and LMM-heparin in man. The elimination rate was similar using the heparin-tyramine bead assay compared with the anti-factor Xa coagulation assay. After intravenous dosing of LMM-heparin the maximal concentration was lower using the heparin-tyramine bead assay compared with the anti-factor Xa coagulation assay. The bead assay was found to be reproducible, valid, and rapid for measurement of the concentration of heparin preparations in purified systems and for HMM-heparin in plasma. Measurement of the concentration of LMM-heparin in plasma has a high coefficient of variation using the binding assay.

Binding, Competitive↗
PubMed1995

Dynamics in aqueous solutions of the pentasaccharide corresponding to the binding site of heparin for antithrombin III studied by NMR relaxation measurements.

1H NMR and 13C NMR relaxation measurements at different magnetic field strengths were used to study the nature of overall and internal motions, in aqueous solution, of the synthetic pentasaccharide (A-G-A*-I-AM) corresponding to the binding site of heparin for antithrombin III. Two-dimensional double INEPT spectra were recorded at 11.7 T with and without suppression of cross-correlation effects between dipolar and chemical shift anisotropy relaxation mechanisms in measurements of spin-lattice and spin-spin relaxation times. Moreover, longitudinal relaxation times were collected at 7 T with the inversion recovery method. One dimensional NOESY spectra were recorded at 11.7 T and 9.4 T with various mixing times when spins of the A1* and A4* protons were inverted in the central residue of the pentasaccharide. Differences in the T1 relaxation times, as well as in the cross-relaxation rates between protons relaxing through fixed distances in the A* residue, indicated that the molecule tumbles anisotropically in solution. However, in order to achieve agreement between the spectral and the model data, the presence of internal motions had to be also considered, in addition to the assumption of a symmetric top model for the description of overall tumbling. The changes in the longitudinal and transversal relaxation times, collected with and without suppression of interference effects, supported the assumption that the cross-correlation between dipolar and chemical shift anisotropy relaxation mechanisms cannot be neglected in this medium-sized molecule. In fact, the influence of these effects was 10-15% in T1 and 20-25% in T2 relaxation times. The experimental data were analyzed using model free formalism and the computed order parameters indicate a decrease in spatial restriction from the central residue (S2 approximately 0.9) towards both ends of the pentasaccharide (S2 approximately 0.7). The anisotropy ratio found was approximately 3.3 with correlation times tau parallel = 450 ps and tau perpendicular = 1480 ps. The values of effective correlation time were within the range of tens of picoseconds. Thus, for a more precise interpretation of the experimental data for the pentasaccharide, in addition to internal motions and anisotropic tumbling, the effect of cross-correlation must be taken into account as well.

Antithrombins↗
PubMed1995

Metabolic and bone effects after administration of ipriflavone and salmon calcitonin in postmenopausal osteoporosis.

Forty postmenopausal women with bone mineral density (BMD) > 2 standard deviations below the mean value for healthy age matched controls were enrolled into an open controlled study to evaluate the metabolic and bone effects of ipriflavone (IP) versus salmon calcitonin (sCT) over a 12 month period. Both treatments significantly increased BMD after 6 and 12 months. A 4.3% increase of BMD was obtained in the IP treated group and a 1.9% in the sCT treated group after 12 months (p < 0.001 between treatments). Bone metabolism markers (serum osteocalcin, alkaline phosphatase, urinary calcium and hydroxyproline/creatinine ratio) were significantly reduced in both groups (p < 0.001). The reduction of urinary hydroxyproline/creatinine ratio was significantly greater (p < 0.05) in the IP group after 12 months. Both treatments were well tolerated. Four patients in the IP group reported gastralgia while two patients in the sCT group reported pruritus and one patient epistaxis.

Aged↗