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Biomedical subjects

G Torri

Publications and source records attributed to G Torri.

At least 181 records · Page 10Linked to original sources
PubMed1985

Fractionation and structural features of two heparin families with high antithrombotic, antilipemic and anticoagulant activities.

15 heparin preparations from bovine intestine, pancreas and lung and hog intestine were fractionated in two main components by selective barium precipitation. The ones that precipitated at room temperature with barium (slow moving (SM)-heparins) had a high anticoagulant activity measured by the USP and APTT (activated partial thromboplastin time) assay and low antithrombotic activity by the Yin and Wessler method. The fractions precipitated at 5 degrees C with barium (fast moving (FM)-heparins) had a low anticoagulant action and high antithrombotic activity. The maximum anti-Xa activity (chromogenic method) was present in heparins with molecular weights around 12-15 X 10(3) daltons whereas high APTT and LPL releasing activities were present in SM-heparins with molecular weights of 30-40 X 10(3) and 15-25 X 10(3) daltons, respectively. FM-heparins had a higher anti-Xa activity and lower lipoprotein lipase (LPL)-releasing activity when compared with the SM-heparins with the same molecular weights. Significant structural differences were observed between SM- and FM-heparins by 13C-NMR spectra and enzymatic degradation with heparinase and heparitinase from Flavobacterium heparinum. Also, significant differences were observed for anti-Xa and anticoagulant activities for the two types of heparins depending on the pharmacological assay used.

Animals↗
PubMed1984

Effect of naloxone on the loss of consciousness induced by i.v. anaesthetic agents in man.

The effect of a specific opioid antagonist, naloxone, was studied in two comparable groups of patients who received i.v. the dose of an anaesthetic agent required to produce loss of consciousness in 50% of subjects. The first group received naloxone 0.006 mg kg-1 5 min before induction of anaesthesia; the second group received a similar volume of saline solution. Thiopentone, Althesin, diazepam, ketamine and propanidid were studied. The differences in percentage of unconscious patients between the naloxone-treated group and the control group were statistically significant for diazepam, ketamine and propanidid. Naloxone did not modify the induction of anaesthesia with thiopentone or Althesin.

Adult↗
PubMed1983

Correlation between structure, fat-clearing and anticoagulant properties of heparins and heparan sulphates.

Heparins and heparan sulphates from different organs, of high purity by accepted criteria, were characterized by chemical and physical (including electrophoretic and 13C-NMR spectroscopic) methods. The fat-clearing activity of these preparations was shown to be correlated with their content of the trisulphated disaccharide units I2S-ANS,6S (L-iduronic acid 2-O-sulphate-N-sulphated D-glucosamino 6-O sulphate). Species with low anti-lipemic activity contained significant proportions (greater than or equal to 30%) of nonsulphated uronic acids (especially D-glucuronic acid), and of D-glucosamino residues undersulphated at C-6, these latter residues being partially N-acetylated. Heparins from beef lung and sheep mucosa, predominantly consisting of trisulphated disaccharide units, displayed consistently higher antilipemic activity than the more heterogeneous pig mucosal heparins. The anticoagulant activity (as determined by the U.S.P., APTT and anti-Xa tests) was not a simple function of the measured physicochemical parameters. Trends were confirmed for pig mucosal heparins being more anticoagulant than beef lung preparations, and low molecular weight (usually undersulphated) species being more active in the anti-Xa test than in the U.S.P. and APTT tests.

Amino Acids↗
PubMed1981

The structure of heparin oligosaccharide fragments with high anti-(factor Xa) activity containing the minimal antithrombin III-binding sequence. Chemical and 13C nuclear-magnetic-resonance studies.

The chemical composition and the 13C n.m.r. spectra of heparin oligosaccharides (essentially octasaccharides), having high affinity for antithrombin III and high anti-(Factor Xa) activity, prepared by three independent approaches (extraction, partial deaminative cleavage with HNO2 and partial depolymerization with bacterial heparinase), leading to different terminal residues, have been studied and compared with those of the corresponding inactive species. Combined wit chemical data, the spectra of the active oligosaccharides and of their fragmentation products afforded information on composition and sequence. The three types of active oligosaccharides were shown to have the common hexasaccharide core I-Aa-G-As*-Is-As, where I and alpha-L-idopyranosyl-uronic acid, Aa = 2-acetamido-2-deoxy-alpha-D-glucopyranose, G = beta-D-glucopyranosyl-uronic acid, Is = alpha-L-idopyranosyluronic acid 2-O-sulphate, As = 2-deoxy-2-sulphamino-alpha-D-glucopyranose 6-O-sulphate. The fourth residue (As*) is an unusually substituted amino sugar resistant to mild deamination. The 13C spectra of the active species are characterized by signals from the above atypical amino sugar, the most evident of which is at 57.7 p.p.m. These signals, compared with those of appropriate synthetic model compounds, are compatible with the recently proposed 3-O-sulphation of the residue As* [Lindahl, Bäckström, Thunberg & Leder (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 6551-6555].

Animals↗
PubMed1981

Plasma protein concentration and recovery from anaesthesia in man.

The effect of the concentration of plasma protein on the recovery from anaesthesia induced by equipotent doses (UD95) of thiopentone and Althesin was studied in 48 patients. The recovery time (RT) wa plotted against the concentrations of total plasma proteins (TPP) and albumin (Al). A small decrease in TPP concentration from normal range affected the recovery time minimally; a small decrease in TPP concentration from a low basal value markedly increased the recovery time with both agents. A large decrease in TPP concentration increased the recovery time from thiopentone and Althesin markedly.

Adult↗
PubMed1980

Experimental osteosarcoma in the mouse, induced by Moloney's murine sarcoma virus.

The writers report an experimental trial on the mouse, consisting in the induction of osteosarcoma by inoculation of Moloney's murine sarcoma virus (MSV-M) into the proximal metaphysis of the tibia. This experiment was conducted on 90 BALB/c female mice aged twenty-one days and of mean weight 12.8 g. One group of animals was also given immunodepressive drugs. The tumour developed in 100 per cent of cases, producing metastases in some of the animals and resulting in death in three cases. The radiographic changes were initially osteolytic followed later by new bone formation. The histological examinations confirmed that the tumour was of an osteosarcomatous nature. Cells characteristic of rhabdomyosarcoma were observed in the soft tissues surrounding the bone. The skeletal metastases had the characteristics of osteosarcoma, while those in the lymph glands and lungs had those of an undifferentiated sarcoma. The writers also took into consideration a series of previous trial performed at the Institute of Clinical Orthopaedics of the University of Milan, involving a total of 740 mice, in arriving at their final conclusion that MSV-M induces, in the mouse, an osteosarcoma similar to spontaneous osteosarcoma in man, capable of producing osteoid tissue, of giving rise to metastases, and of causing the death of the animal.

Animals↗
PubMed1980

[Effect of proteinemia on recovery: a comparison between thiopentone and alphaxolone (althesin)].

The effect of proteinaemia and albuminaemia changes on recovery time following administration of an equipotent dose (DPC95) of thiopentone and alphaxolone has been evaluated. The study was carried out on two groups of 24 patients premedicated with atropine alone. Recovery time was more closely related to variations in albuminaemia compared to variations in total proteins: this results that albumins are the main binding-site of i.v. anaesthetics. Variations in total proteins and albuminaemia affect recovery time to a lesser extent when alphaxolone is used, compared with thiopentone. The result is related to the lower alphaxolone binding fraction. The clinical implications of protein binding fraction of anaesthetics is discussed.

Adult↗
PubMed1980

Experimental suture of the peripheral nerves with "fibrin glue".

An experiment on rats is presented, concerned with a technique for suturing peripheral nerves by means of "human fibrin glue". The sutures were performed by three different methods: (1) the traditional technique; (2) using a special grooved Vitallium plate (presented by the authors in a previous paper) by means of which all sutures can be dispensed with, and which facilitates more rapid and complete regeneration of the nerve; (3) with "fibrin glue", used on its own or together with the special plate. On comparing the three methods it was found that fibrin glue achieves better approximation of the nerve ends and thus leads to more rapid and more complete regeneration of the peripheral nerve fibres. Combined use with the plate is preferred where there is a minimal loss of nerve substance.

Animals↗
PubMed1980

Glycosaminoglycans from pig duodenum.

A polysaccharide extract from pig duodenum, used in therapy as antilipemic, was shown by chromatographic and electrophoretic methods to be a mixture of the glycosaminoglycans (GAG) heparin (HEP), heparan sulfate (HS), dermatan sulfate (DeS), chondroitin sulfates (ChS) and hyaluronic acid (HA), in the ratio 24:31:23:9:13. The GAG mixture was fractionated with alkyl-ammonium salts, and, for DeS, with copper salts. Further purification of the fractions either by repeated complexation or by removal of residual impurities using specific enzymes or chemical reactions, permitted obtaining individual GAG more than 97% pure by electrophoretic and 1H-NMR analysis. These preparations will be used to assess the contribution of individual GAG to the biological activity of duodenal GAG extracts.

Animals↗
PubMed1979

The relative potencies of thiopentone, ketamine, propanidid, alphaxalone and diazepam. A statistical study in man.

The potency of five i.v. anaesthetics (thiopentone, ketamine, alphaxalone (Althesin), propanidid and diazepam) was studied by determining the dose required to produce unconsciousness in 50% (UD50) and 95% (UD95) of patients. UD50 and UD95 were determined using the probit method. The effect of age on the anaesthetic requirement has been studied also. Relative to thiopentone, the potency was alphaxalone 9.22, diazepam 5.24, ketamine 4.37 and propanidid 1.006.

Adult↗
PubMed1977

Effects of uneven elastic loads on breathing pattern of anesthetized and conscious men.

In anesthetized subjects rib cage strapping (RCS) did not change tidal volume (VT) and increased ventilation (V), whereas abdomen strapping (AS) markedly decreased VT and V. Both kinds of strapping decreased expiratory duration (TE), but did not change inspiratory duration (TI) and breathing rate. RCS and AS decreased lung volume by about 200 ml and increased the elastance of the repiratory system by 12 cm H2O/1 and 9 CM H20/l, repectively. The changes produced are mainly due to mechanical factors, although reflexes also seem to be operating in some cases. In conscious subjects RCS decreased VT, TI, TE and did not change V, whereas AS did not change these parameters. The different changes in conscious and anesthetized subjects show the effects of cortical influences, which also partly explain the differen effects elicited in conscious subjects by RCS and AS. The effects produced by RCS are mainly due to the sensation of hindrance to rib cage expansion, rather than to that of rib cage squeezing, as shown by experiments of RCS without reduction of rib cage volume.

Abdomen↗
PubMed1977

Role of synovectomy in hemophilic arthropathy.

Fifteen knee synovectomies performed in severe hemophiliacs between 1969 and 1971 were reevaluated after a follow-up period ranging from five to seven years. In the majority of cases (53%) there was no recurrence of hemarthrosis; in the others the condition was reduced (40%) or unchanged (7%) and joint scintiscans carried out with 99mTc showed a significant uptake of the tracer. Joint motion was markedly impaired in eight cases despite prolonged and intensive physiotherapy. The majority of patients expressed satisfaction with the operation, which had reduced the frequency and severity of joint bleeding and allowed them to lead more active lives. It is suggested that the possibilities of the conservative treatment presently available should be more extensively explored before establishing the indications for synovectomy.

Adolescent↗
PubMed1976

A study of the development of fracture callus in the presence of an experimentally induced osteosarcoma.

The results of two experiments are reported in which the formation of an osteosarcoma was induced in mice by the intraosseous injection of Moloney's virus. In the first group of fifty mice, a complete diaphyseal fracture was carried out nine days later at the site of the tumour. In the second group of 200 mice, a partial fracture was produced at the time of injection so that immobilisation was assured. The effects of cyclophosphamide and calcitonin administration were also studied in this group. The course of the repair processes of the bone was studied in both groups, and showed that, even in the presence of an osteosarcoma, these begin and can reach completion, though obstructed and delayed by the tumour.

Animals↗