PubMed Health⌕ Search

Biomedical subjects

A Lamberti

Publications and source records attributed to A Lamberti.

At least 73 records · Page 4Linked to original sources
PubMed1983

[Polydermatomyositis in the adult and its management].

Polydermatomyositis is a chronic, non-suppurative disease of the striated muscle. In practice, the diagnostic criteria are often associated with other factors--alcoholism, corticotherapy--which, by themselves, may induce myopathy. In adults, the possible association of dermatomyositis with cancer rises the problem of scanning for neoplasia at regular intervals. In addition to corticotherapy, physical therapy helps the patient to maintain maximal autonomy.

Adrenal Cortex Hormones↗
PubMed1983

Brain atrophy, peripheral neuropathy and folic acid deficiency.

A woman with peripheral neuropathy and cerebral atrophy, both secondary to a selective folic acid deficiency caused by severe gastrointestinal disturbances, was given folic acid replacement therapy, which improved her clinical, blood and neurophysiological status.

Atrophy↗
PubMed1979

Threonine deaminase: autogenous regulator of the ilv genes in Escherichia coli K-12.

In this paper we analyze the effect of mutations in three genes, ilvO, ilvA and rho, on the expression of the ilvEJGDA gene cluster of Escherichia coli K-12. The ilvO603 mutation causes a cis-dominant derepression of the ilvEJGDA genes. In particular, the ilvG gene, not expressed in the wild type, becomes expressed in the ilvO603 strain. We have introduced ilvA mutations (ilvA454 or ilvA628) in the ilvO603 strain and we show that ilvG expression requires the presence in cis of both an ilvO603 mutation and of an ilvA+ allele. The ilvG gene is not expressed when in trans is present an ilvO+, ilvA+ genotype. However, it is expressed when the chromosome in trans is ilvO603, ilvA+ (ilvG-). We suggest that ilvO603 is part of ilvA, the structural gene for threonine deaminase, and that threonine deaminase from the ilvO603 mutant binds the ilvO603 site and not the ilvO+ site. Therefore, the ilvA gene product would be a cis-acting protein. Mutations in the rho gene cause derepression of the ilvEJGDA gene cluster without a concomitant expression of the ilvG gene. We show that introduction of either a rho-218 or a rho-115 mutation into the ilvO603, ilvA454 double mutant causes expression of ilvG. We therefore suggest that the ilvA gene product, threonine deaminase, is involved in termination of transcription as an antagonist of the rho gene product. Introduction of ilvA454 into an ilvO603 strain causes also a decrease in expression of the ilvE, ilvJ and ilvD genes. This effect is maximum in the case of the ilvD gene and we studied it in detail in isogenic strains containing also the rho-218 mutation.

Escherichia coli↗
PubMed1979

[Atrioventricular canal associated with Fallot's tetralogy. Anatomo-clinical study of 2 cases].

The Authors are examing two cases of A-V canal associated with T. of Fallot. The most important clinical aspects of this rare cardiopathy result in the following: -- the frequent coexistence with Down dyndrome; -- the ECG and VCG aspects of counterclockwise rotation of the initial vectors of QRS in the frontal plane; -- the simultaneous observation of the typical echocardiographical aspects of both kinds of cardiopathy. The injection of dye into both ventricles allows the precise diagnosis. The post-mortem study in both cases shows the morphology of A-V canal associated with the one of T. of Fallot. From the surgical point of view it is important to take into account the abnormal morphology and extension of VSD. The importance of the part that the conal cushion plays in the morphogenesis of the malformation is discussed.

Adolescent↗
PubMed1978

Dual autogenous regulatory role of threonine deaminase in Escherichia coli K-12.

We describe the regulatory properties of two strains carrying either the ilvA624 or the ilvA625 mutations, located in the structural gene for threonine deaminase. Crude extracts of both these strains possess a threonine deaminase activity migrating on polyacrylamide gels, differently from the wild type enzyme. Growth studies demonstrate that these mutations do not cause a limitation of isoleucine biosynthesis, suggesting normal catalytic activity of deaminase. A regulatory consequence of the ilvA624 allele is a derepression of the isoleucine-valine biosynthetic enzymes, which is recessive to an ilvA+ allele. The ilvA625 mutation causes a derepression which is dominant in an ilvA625/ILVA+ diploid. We interpret these data assuming that threonine deaminase, previously shown to be an autogenous regulator of the ilv genes, lacks a repressor function in the ilvA624 mutant, while in the ilvA625 mutant it is a better activator than wild type threonine deaminase. The data are discussed in terms of a model requiring that threonine deaminase, or a precursor of it, is in equilibrium between two forms, one being an activator of gene expression and the other being a repressor.

Escherichia coli↗
PubMed1977

Growth inhibition of Escherichia coli K-12 by L-valine: a consequence of a regulatory pattern.

We studied the production of the ilvG gene product, the valine resistant acetolactate synthase isoenzyme II, in an ilvO+ G+ ilvB ilvHI derivative of Escherichia coli K-12. This strain contains mutations in the structural genes for the valine sensitive acetolactate synthase isoenzymes I and III. We find that the ilvG gene is not expressed in this strain when gworn with either isoleucine and valine or with isoleucine, leucine and valine, or when limited for either isoleucine or valine. Since we previously found that the ilvG gene is expressed in an ilvO603 containing strain (Favre et al., 1976), we presume that the mechanism by which E. coli K-12 regulates the ilv gene cluster is responsible for the lack of ilvG expression in the ilvO+ strain. The valine sensitivity of E. Coli K-12 is a consequence of this regulatory pattern.

Acetolactate Synthase↗
PubMed1973

Escherichia coli K-12 mutants altered in the transport systems for oligo- and dipeptides.

Two mutants of Escherichia coli K-12, defective in the oligopeptide and dipeptide transport system, are described. A mutant defective in the oligopeptide transport system (opp-1) was isolated as resistant to the inhibitory action of triornithine; this mutant is also resistant to glycylglycylvaline and does not concentrate (14)C-glycylglycylglycine, although it is still as sensitive as the parental strain to glycylvaline and valine. Starting from the opp-1 strain, a mutant defective also in the dipeptide transport system (dpp-1) was isolated; this mutant is resistant to the inhibitory action of glycylvaline, valylleucine, and leucylvaline and does not concentrate (14)C-glycylglycine, although it is still as sensitive as the parental strain to valine. The apparent kinetic constants for oligopeptide and dipeptide transport were measured. The opp marker is co-transducible with trp at 27 min on the E. coli genetic map. The dpp locus is separated from opp and is located between proC (10 min) and opp.

Carbon Radioisotopes↗
PubMed1971

Invitro formation of assimilatory reduced nicotinamide adenine dinucleotide phosphate: nitrate reductase from a Neurospora mutant and a component of molybdenum-enzymes.

An active Neurospora-like assimilatory NADPH-nitrate reductase (EC 1.6.6.2), which can be formed in vitro by incubation of extracts of nitrate-induced Neurospora crassa mutant nit-1 with extracts of (a) certain other nonallelic nitrate reductase mutants, (b) uninduced wild type, or (c) xanthine oxidizing and liver aldehyde-oxidase systems was also formed by combination of the nit-1 extract with other acid-treated enzymes known to contain molybdenum. These molybdenum enzymes included (a) nitrogenase, or its molybdenum-iron protein, from Clostridium, Azotobacter, and soybeannodule bacteroids, (b) bovine liver sulfite oxidase, (c) respiratory formate-nitrate reductase from Escherichia coli, (d) NADH-nitrate reductase from foxtail grass (Setaria faberii), and (e) FADH(2)- and reduced methyl viologennitrate reductase preparations from certain Neurospora mutants. Several molybdenum-amino-acid complexes, as possible catalytic models of nitrogenase, were inactive (as were some previously tested 20 nonmolybdenum enzymes) in place of the acid-treated molybdenum-containing enzymes. The results imply the existence of a molybdenum-containing component shared by the known molybdenum-enzymes.

Animals↗