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Biomedical subjects

R Longhi

Publications and source records attributed to R Longhi.

At least 109 records · Page 6Linked to original sources
PubMed1985

Cranial computerized tomography in dihydropteridine reductase deficiency.

Dihydropteridine reductase deficiency is a rare cause of hyperphenylalaninaemia, characterized by severe and progressive neurological impairment, despite early and accurate dietary control of plasma phenylalanine. We describe two girls, diagnosed at 17 and 14 months of age, respectively, and immediately treated with L-dopa, 5-hydroxytryptophan and carbidopa. In spite of an adequate dietary and pharmacological treatment, the clinical and neurological pictures progressively worsened. Repeated cranial computerized axial tomography scans showed degeneration of the white matter and, in one case, calcification of the basal ganglia. The possible association of this last finding with folate depletion is discussed.

Amino Acid Metabolism, Inborn Errors↗
PubMed1985

High-performance liquid chromatography of glucagon and related compounds.

Glycerolpropylsilane bonded phases have been found to adsorb peptides and proteins via ionic interactions. In this paper high-performance liquid chromatography separation of glucagon and related compounds, using a Diol-silica matrix, is described. Crystalline, commercial preparations of glucagon, when analyzed on LiChrosorb Diol columns eluted with low-ionic-strength acidic buffers, contained up to four contaminant peaks, in different numbers and ratios. Three of these contaminants, called A, C, and D, were recovered and characterized. Contaminant A, representing a few percent of the total, was a mixture of mono- and didesamidoglucagon, as shown by treatment with bis(I,I-trifluoroacetoxy)iodobenzene, with which it is possible to differentiate between carboxamide and carboxylic acid residues. Contaminant C, ranging from 0 to about 30% of the total, was N-terminal degraded glucagon. Contaminant D, ranging from a few percent to about 25% of the total, was (Met27 sulfoxide) glucagon.

Amino Acids↗
PubMed1985

[Cardiac tolerance of a beta-2-sympathomimetic spray: fenoterol. Apropos of 37 patients followed using a Holter monitor during a brief treatment protocol].

37 subjects with stable asthma and a mean age of 50.3 undertook a protocol to study the cardiac tolerance to a spray B2SM. A Holter monitor was performed before and 48 hours after the institution of a Fenoterol spray in 4 daily doses of 600 micrograms at fixed times. Before starting treatment with a beta 2 sympathomimetic spray (B2SM) 11 subjects had abnormal traces with significant auricular extra-systoles in 4, ventricular extra-systoles in 5 and both in one subject: one patient had a run of ventricular tachycardia without symptoms. On Fenoterol, a worsening of pre-existing extra systoles was noted thrice, one was auricular the other two ventricular. Two patients had brief runs of ventricular tachycardia but the role of Fenoterol was uncertain; one of the patients was very elderly and hypoxaemic. In the second and elevated theophylline level of 20 micrograms/l was noted. The arrythmogenic power of a B2SM seems weak, but in certain situations such as hypoxaemia, metabolic acidosis and overdosage of theophylline, over consumption of B2SM in association with the above factors could contribute to serious arrhythmias. Also in this study in which there was a protocol limited in time, no premature conclusion should be made on the crucial problem of the cardiovascular risks of B2SM in the basic treatment of asthma but raises the problem of the arrythmogenic potential of the drug association of Theophylline + B2SM.

Adult↗
PubMed1980

Renaturation and urea-induced denaturation of 20 beta-hydroxysteroid dehydrogenase studied in solution and in the immobilized state.

Tetrameric 20 beta-hydroxysteroid dehydrogenase (17,20 beta,21-trihydroxysteroid:NAD+ oxidoreductase, EC 1.1.1.53) from Streptomyces hydrogenans was reactivated after inactivation, dissociation and denaturation with urea. The effect of several factors such as NAD+, NADH, substrate, sulphydryl reducing agents, extraneous proteins, pH and enzyme concentration on reactivation was investigated. The coenzymes were found to be essential for obtaining a high reactivation yield (about 90%), since in their absence the reactivation was less than 10%. NADH was effective at lower concentrations than NAD+. The reactivated enzyme, after the removal of inactive aggregates, showed physical and catalytic properties coincident with those of the native enzyme. The mechanism by which NADH affects the reconstitution of 20 beta-hydroxysteroid dehydrogenase was investigated using both soluble enzyme and enzyme immobilized on Sepharose 4B. The immobilization demonstrates that isolated subunits are inactive and incapable of binding NADH and suggests that subunit association to the tetramer is essential for enzymatic activity. NADH appears to act, after subunit assembly has taken place, by stabilizing tetramers and preventing their aggregation with monomers that would give rise to inactive polymers.

20-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Effect of granulocyte-colony stimulating factor in glycogen storage disease type Ib.

Five children with glycogen storage disease type Ib (glycogenosis Ib), a metabolic defect associated with neutropenia and impairment of neutrophil function, were treated with granulocyte colony stimulating factor, a haemopoietic growth factor that induces a significant increase in polymorphonuclear leucocyte count in vivo. Recurrent bacterial or fungal infections were recorded in the three patients who had very low polymorphonuclear leucocyte counts. Experience at this centre indicates that the absolute number of polymorphonuclear leucocytes is more important than the alteration of their metabolic function in determining the susceptibility of the patients to infection. Granulocyte colony stimulating factor was effective at increasing polymorphonuclear leucocyte numbers (and restored function to some extent) in patients with glycogenosis Ib. This drug might be beneficial in cases of severe infection, in glycogenesis Ib patients with neutropenia.

Bacterial Infections↗
PubMedDate not supplied

[Schönlein-Henoch syndrome: clinical-epidemiological analysis of 98 cases].

We analyzed the clinical and epidemiological data of 98 patients (50 males and 48 females) aged between 6 months and 16 years, hospitalized for Schönlein-Henoch syndrome in the last 20 years. The incidence was higher during spring time. Throat culture was positive for streptococcus pyogenes in 16% of patients. 14 of 60 (23%) had a positive allergometric response to various tests. The extrarenal manifestations were: purpura (100%), articular (68%) or gastrointestinal (32%) involvement and orchitis (10%). Renal symptoms were observed in 23% of the patients, but a clear nephropathy was documented just in 5% of the cases, with resolution within 2 years. Our data suggest, in agreement with the letterature, that renal involvement in Schönlein-Henoch syndrome has usually a benign course.

Adolescent↗
PubMedDate not supplied

HIV neutralizing IgA in exposed seronegative subjects recognise an epitope within the gp41 coiled-coil pocket.

Human immunodeficiency virus (HIV)-specific IgA can be detected in cervical secretions, saliva, and sera of HIV-infected and HIV-uninfected individuals with a known exposure to the virus. IgA from HIV-uninfected exposed seronegative individuals (ESN) neutralize in vitro primary strains of HIV-1. We analyzed the epitopes of HIV recognized by serum HIV-specific IgA of ESN individuals to identify the antigenic correlates of HIV neutralization in exposed-uninfected subjects, and to verify whether different epitopes would be recognized by HIV-specific IgA of ESN and of HIV-infected patients. Results confirmed that HIV-neutralizing IgA are detected in sera of ESN and showed that neutralization of primary HIV strains is mediated by the recognition of different epitopes in HIV-infected patients and ESN. Thus, whereas IgA of HIV+ individuals recognize epitopes expressed both within gp120 and gp41, IgA of ESN exclusively bind to gp41-expressed epitopes. Epitope mapping revealed that the epitope recognized by serum IgA of ESN on gp41 is restricted to aa 581-584 (LQAR) and corresponds to coiled coil pocket in the alpha helic region. In contrast, the epitope seen by IgA of HIV-infected patients on gp41 is identified by two regions; the first is contained within the cystein loop (aa 589-618), the second correspond to C terminal region in the extra membrane region of gp 41 (aa 642-673). Thus, we have identified and characterized the epitopes that mediate neutralization of HIV in individuals in whom infection does not occur despite multiple exposures to the virus. These results have important implications for the development of a new therapy against HIV infection.

Acquired Immunodeficiency Syndrome↗