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Biomedical subjects

M Galli

Publications and source records attributed to M Galli.

At least 19 recordsLinked to original sources
PubMed1992

Anticoagulant activity of beta 2-glycoprotein I is potentiated by a distinct subgroup of anticardiolipin antibodies.

Plasmas of 16 patients positive for both IgG anticardiolipin (aCL) antibodies and lupus anticoagulant (LA) antibodies were subjected to adsorption with liposomes containing cardiolipin. In 5 of these plasmas both the anticardiolipin and the anticoagulant activities were co-sedimented with the liposomes in a dose-dependent manner, whereas in the remaining cases only the anticardiolipin activity could be removed by the liposomes, leaving the anticoagulant activity (LA) in the supernatant plasma. aCL antibodies purified from the first 5 plasmas were defined as aCL-type A, while the term aCL-type B was used for antibodies in the other 11 plasmas, from which 2 were selected for this study. Prolongation of the dRVVT was produced by affinity-purified aCL-type A antibodies in plasma of human as well as animal (bovine, rat and goat) origin. aCL-type B antibodies were found to be devoid of anticoagulant activity, while the corresponding supernatants containing LA IgG produced prolongation of the dRVVT only in human plasma. These anticoagulant activities of aCL-type A and of LA IgG's were subsequently evaluated in human plasma depleted of beta 2-glycoprotein I (beta 2-GPI), a protein which was previously shown to be essential in the binding of aCL antibodies to anionic phospholipids. Prolongation of the dRVVT by aCL-type A antibodies was abolished using beta 2-GPI deficient plasma, but could be restored upon addition of beta 2-GPI. In contrast, LA IgG caused prolongation of the dRVVT irrespective of the presence or absence of beta 2-GPI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Determination of glutamic acid decarboxylase activity and inhibition by an H2O2-sensing glutamic acid oxidase biosensor.

The catalytic activity of the enzyme L-glutamic acid decarboxylase (GAD) is determined by an amperometric method based on a recently developed glutamate-selective biosensor. The biosensor is composed of an amperometric H2O2 electrode and a biocatalytic membrane containing the enzyme glutamic acid oxidase (GAO). The biosensor allows the direct and continuous measurement of GA levels by monitoring the H2O2 produced at the electrode interface as a coproduct of the GAO-catalyzed GA oxidation to alpha-ketoglutaric acid. Since GA is transformed to gamma-aminobutyric acid and CO2 under the catalytic activity of GAD, the rate of GA consumption in solution, monitored by the GAO biosensor, represents a reliable measure of GAD catalytic activity. Additional experiments performed in the presence of different concentrations of the GAD inhibitor valproic acid have shown the suitability of the proposed approach for the study of GAD inhibitors also. Discussion of the main experimental characteristics of this new analytical method is given in terms of sensitivity, reproducibility, and reliability of the experimental results and ease, time, and cost of operation.

Amino Acid Oxidoreductases↗
PubMed1992

Cortisol resistance in acquired immunodeficiency syndrome.

This study concerns 9 iv drug abusers with acquired immunodeficiency syndrome (AIDS) who developed hypercortisolism without the clinical signs or metabolic consequences of hypercortisolism. All patients were characterized by an Addisonian picture (weakness, weight loss, hypotension, hyponatremia, and intense mucocutaneous melanosis). An acquired form of peripheral resistance to glucocorticoids was suspected. We, therefore, examined glucocorticoid receptor characteristics on mononuclear leukocytes by measuring [3H]dexamethasone binding and the effect of dexamethasone on [3H]thymidine incorporation, which is one of the effects of glucocorticoid receptor activation. Glucocorticoid receptor density was increased in AIDS patients with an Addisonian picture (group 1; 16.2 +/- 9.4 fmol/million cells) compared to values in 12 AIDS patients without an Addisonian picture (group 2; 6.05 +/- 2.6 fmol/million cells; P less than 0.01) and sex- and age-matched controls (3.15 +/- 2.3 fmol/million cells; P less than 0.01). The affinity of glucocorticoid receptors (Kd) was strikingly decreased (9.36 +/- 3.44 nM in group 1; 3.2 +/- 1.5 nM in group 2; 2.0 +/- 0.8 nM in controls; P less than 0.01). [3H]Thymidine incorporation was decreased dose-dependently by dexamethasone in controls and patients; the effect was significantly blunted (P less than 0.05) in group 1 patients, which suggests that activation of glucocorticoid receptor is impaired as a result of the glucocorticoid receptor abnormality. In conclusion, AIDS patients with hypercortisolism and clinical features of peripheral resistance to glucocorticoids are characterized by abnormal glucocorticoid receptors on lymphocytes. Resistance to glucocorticoids implies a complex change in immune-endocrine function, which may be important in the course of immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Quantitative evaluation of the brain electrical activity of patients suffering from chronic obstructive bronchopneumonopathy (COBP).

The authors subjected 66 patients suffering from COBP with chronic respiratory insufficiency (22 with EGA values within standard limits, 44 with irregular PO2 and PCO2 values) to an electroencephalography with BEAM (brain electrical activity mapping). In the absence of clinically noticeable symptoms or neurologic signs of central type, more than 65% of the patients showed an increase of slow activities together with a reduction of the alpha activity presumably imputable only to the respiratory pathology.

Adult↗
PubMed1991

Lupus anticoagulant IgG's (LA) are not directed to phospholipids only, but to a complex of lipid-bound human prothrombin.

Plasmas from 16 patients that were found to be positive both for anticardiolipin antibodies (ACA) and lupus anticoagulants (LA) were incubated with liposomes that contained anionic phospholipids. In 11 of these plasmas, ACA could be cosedimented with the liposomes in a dose-dependent manner, whereas LA activity of the remaining supernatant was unaffected. LA activity of purified total IgG from 6 patients was measured in three different coagulation tests, using normal plasmas from different species. Prolongation of the aPTT, KCT and dRVV clotting times was observed only with normal plasma from human origin, not with bovine, rat or sheep plasma. Highly purified coagulation factors Xa, Va and prothrombin, both of human and bovine origin, were used to establish for two patient IgG's the effect of LA on the rate of thrombin formation in the presence and absence of lipid vesicles composed of 20 mole% phosphatidylserine and 80 mole% phosphatidylcholine. A strong and dose dependent inhibition by LA was observed only when human prothrombin was used as substrate in the prothrombinase complex in the presence of lipids. No inhibition was found when bovine prothrombin was used as substrate. The inhibitory effect observed in the presence of human prothrombin was independent of the source of factors Xa and Va, and was not found in the absence of lipid. Preliminary binding studies suggest that LA only associate with a lipid surface, provided that human prothrombin and calcium ions are present. These data indicate that LA are not directed to phospholipids alone, but presumably recognize an epitope which becomes exposed upon Ca(2+)-mediated binding of human prothrombin to phospholipids.

Adult↗
PubMed1991

Accuracy and safety of technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile (Sestamibi) myocardial scintigraphy with high dose dipyridamole test in patients with effort angina pectoris: a multicenter study. Italian Group of Nuclear Cardiology.

Clinical and physiologic evidence indicates that maximal coronary vasodilation is not achieved in a large number of patients with use of the standard dose of dipyridamole (0.56 mg/kg body weight over 4 min). The feasibility, safety and accuracy of technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile (Sestamibi) scintigraphy associated with intravenous high dose dipyridamole (0.56 mg/kg over 4 min followed 4 min later by an additional 0.28 mg/kg over 2 min) were evaluated in a multicenter study. Planar myocardial perfusion images were obtained at rest and after dipyridamole in 101 patients with effort chest pain and no prior myocardial infarction. High dose dipyridamole (62 patients) was used when typical chest pain or electrocardiographic (ECG) signs of ischemia, or both, did not occur during or after the standard dose (39 patients). With high dose dipyridamole, 34 patients had pain (18 patients) or ECG signs of ischemia (ST depression greater than or equal to 2 mm) (8 patients), or both (8 patients), whereas the other 28 patients had Sestamibi injection in the absence of symptoms or ECG changes. All patients underwent coronary angiography: 81 had significant coronary artery disease (greater than or equal to 50% reduction of lumen diameter) (affecting one vessel in 38, two vessels in 19 and three vessels in 24 patients) and 20 patients had normal coronary arteries. The overall sensitivity, specificity and predictive accuracy of Sestamibi scintigraphy were 81%, 90% and 83%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

In vivo efficacy of intravenous gammaglobulins in patients with lupus anticoagulant is not mediated by an anti-idiotypic mechanism.

The authors have investigated the presence in commercially available intravenous gammaglobulins (IVIg) of anti-idiotypic antibodies directed to Lupus Anticoagulant (LA). In vitro incubation of 4 LA plasmas with increasing concentrations of IVIg (from 0 to 39 mg/ml) resulted in a dose-dependent inhibition of LA activity (the highest inhibitions ranged from 14.0 to 53.4%). Similar results were obtained when patients' plasma was substituted with total IgG (the highest inhibitions ranged from 43.0 to 55.0% and were obtained at IgG:IVIg molar ratios ranging from 1:15 to 1:50). Also the incubation of patients' F(ab')2 with F(ab')2 from IVIg produced a similar dose-dependent inhibition of LA activity. These data are suggestive of an in vitro idiotypic-anti-idiotypic interaction between LA and IVIg. However, when injected in patients with LA, IVIg do not seem to operate by this mechanism of action. In fact, reduction or disappearance of LA was only observed in 2 out of 4 patients; also the quick reappearance of LA activity was not consistent with the time course of anti-idiotypic response. Finally, this effect was reached by half the IVIg concentrations necessary to produce an appreciable inhibitory effect on LA activity in vitro. Thus, it is concluded that, even if IVIg contain anti-idiotypic antibodies reacting with LA, the clinical efficacy of IVIg treatment in patients with these autoantibodies should be attributed to other mechanisms.

Adult↗
PubMed1991

Soluble interleukin-2 receptor decrease in the sera of HIV-infected patients treated with zidovudine.

Laboratory parameters which are modified following administration of zidovudine are becoming increasingly useful in monitoring the efficacy of treatment of early stages of HIV-1 infection. The serum levels of soluble interleukin (sILR)-2 receptor, which have been reported to increase early in HIV-1 infection, were found to be significantly lower in 24 patients being treated with zidovudine than in 69 patients who were not treated, 28 of whom had CD4+ counts greater than 400 x 10(6)/l, and 41 less than 400 x 10(6)/l, respectively (P less than 0.0001). A prospective study group of 33 subjects treated with zidovudine demonstrated a decrease in sIL-2R during therapy (base values 2113 +/- 1131 versus 1444 +/- 728 after 90 days of therapy; P less than 0.0007). The reduction of sIL-2R was greater in those subjects were p24 antigen became negative during treatment. sIL-2R therefore seems to be a useful tool in the monitoring of therapy with zidovudine.

CD4-Positive T-Lymphocytes↗
PubMed1991

Transient prolonged postischemic ventricular dilatation documented by 99mTc MIBI scan.

We describe two cases of prolonged postischemic ventricular dilatation during myocardial scintigraphy with 99mTc MIBI, the new perfusion tracer that has only negligible redistribution. Ventricular dilatation, caused by true chamber dilatation and/or subendocardial ischemia, was still present over two hours after the induced ischemic episode, suggesting a prolonged duration of such a commonly believed fleeting scintigraphic finding.

Cardiomegaly↗
PubMed1991

Effects of mental stress on myocardial perfusion in patients with ischemic heart disease.

The purpose of the present study was to determine whether and to what extent mental stress can reproduce the perfusion defects that are known to be induced by exercise. Twenty-four patients with recent myocardial infarction (New York Heart Association functional class I) and evidence of ischemic response were evaluated by means of SESTAMIBI scintigraphy performed once after exercise and then again within 2 days after mental arithmetic. Baseline, exercise, and mental stress planar scintigrams were divided into 15 segments, and each segment was reviewed and scored on a scale of 0 to 3 by experienced observers using circumferential profile analysis. Conflicting scores were resolved by consensus. Electrocardiographic abnormalities were found in 15 of 24 patients during exercise and in none during mental arithmetic. Chest pain was experienced by five patients during exercise and by none during mental stress. Twenty patients showed reversible perfusion defects during mental stress. Of the 360 pooled scintigram segments, 99 evidenced uptake defects during exercise, and 48 of these showed the same defects during mental stress. Twenty of the remaining 51 of 99 segments were adjacent to segments showing reversible hypoperfusion, suggesting milder hypoperfusion in these segments during mental arithmetic than during exercise. Furthermore, 10 segments showed reversible defects only during mental stress such that seven of these occurred in areas adjacent to those that had shown exercise-induced reversible perfusion defects, two occurred in areas that had shown fixed SESTAMIBI defects during exercise, and one occurred in a segment that had shown completely normal uptake during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗