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Biomedical subjects

L Pinto

Publications and source records attributed to L Pinto.

At least 55 records · Page 3Linked to original sources
PubMed1992

Spectrin/band 3 ratio as diagnostic tool in hereditary spherocytosis.

Recently it has been clearly established that partial deficiency of spectrin (SP) evaluated by radioimmunoassay is a common feature of many different forms of hereditary spherocytosis (HS). In this paper the determination of SP density (spectrin/band 3 ratio) in 46 HS patients and in 50 normal controls is presented. The comparison between the membrane SP density of HS subjects and controls showed a statistically significant difference (P less than 0.0005). Moreover no overlap between normal and HS subjects was observed. Membrane spectrin/band 3 ratio has been found related to some clinical features: indeed patients with severe HS showed a smaller SP density than those with milder HS. Our results show that the evaluation of membrane SP density permits a prompt diagnosis of HS and avoids extensive and unnecessary studies for other anaemias.

Adolescent↗
PubMed1992

[Persistent ductus arteriosus in the adult--report of a case].

The authors describe a case of congenital heart disease no longer frequent in adults, due to an early diagnosis and surgical treatment. The patent ductus arteriosus in adults who received no therapy can present several forms of evolution, depending on its own hemodynamic profile. The present case is an example of a congenital heart disease not diagnosed during the childhood, that developed pulmonary hypertension and congestive heart failure. These clinical situations have a bad prognosis and place this patient in a group of high surgical risk. Thus, surgery is not advisable considering the bad prognosis and early high mortality rate.

Age Factors↗
PubMed1991

Closely linked lesions in a region of the X chromosome affect central and peripheral steps in gustatory processing in Drosophila.

We have analyzed a set of closely linked mutations on the X chromosome of Drosophila that lead to defects in gustatory behavior. The mutations map to a small region of the X chromosome between 10E1-4. Two distinct complementation groups, gustB and gustD, map to the ends of this region. These groups show complex complementation patterns with the mutations gustC and GT-1, which also map to this region. We describe the behavioral and electrophysiological properties of the mutants. These mutations affect peripheral receptor properties as well as more central processing steps in the gustatory pathway.

Animals↗
PubMed1991

Ankyrin deficiency in dominant hereditary spherocytosis: report of three cases.

We describe three Italian subjects from two unrelated families affected with isolated hereditary spherocytosis (HS) without other clinical abnormalities, associated with partial spectrin and ankyrin deficiency. In both families the propositus has normal biological parents, and thus appears to be the result of a new mutation; in one of them the disease is further transmitted in an autosomal dominant fashion. Cytogenetic analysis of the latter family excluded abnormalities of the short arm of chromosome 8. We speculate that in both kindreds ankyrin deficiency is the primary defect related to ankyrin gene mutation. Several pieces of evidence suggest that ankyrin deficiency is probably the most common molecular defect in HS. It is inherited in a, dominant manner and its clinical and biochemical expression is heterogenous.

Adolescent↗
PubMed1991

Effect of acute hypoxia on respiration and brain stem blood flow in the piglet.

Changes in local brain stem perfusion that alter extracellular fluid Pco2 and/or [H+] near central chemoreceptors may contribute to the decrease in respiration observed during hypoxia after peripheral chemoreceptor denervation and to the delayed decrease observed during hypoxia in the newborn. In this study, we measured the changes in respiration and brain stem blood flow (BBF) during 2-4 min of hypoxic hypoxia in both intact and denervated piglets and calculated the changes in brain stem Pco2 and [H+] that would be expected to occur as a result of the changes in BBF. All animals were anesthetized, spontaneously breathing, and between 2 and 7 days of age. Respiratory and other variables were measured before and during hypoxia in all animals, and BBF (microspheres) was measured in a subgroup of intact and denervated animals at 0, 30, and 260 s and at 0 and 80 s, respectively. During hypoxia, minute ventilation increased and then decreased (biphasic response) in the intact animals but decreased only in the denervated animals. BBF increased in a near linear fashion, and calculated brain stem extracellular fluid Pco2 and [H+] decreased over the first 80 s both before and after denervation. We speculate that a rapid increase in BBF during acute hypoxia decreases brain stem extracellular fluid Pco2 and [H+], which, in turn, negatively modulate the increase in respiratory drive produced by peripheral chemoreceptor input to the central respiratory generator.

Animals↗
PubMed1991

Loss of CD45RA and gain of CD45RO after in vitro activation of lymphocytes from HIV-infected patients.

T-lymphocyte activation is accompanied by a loss of CD45RA determinant and gain of CD45RO marker. Previous work suggests that the CD45RO population could represent the T-cell memory pool since it contains most of the cells that can respond to recall soluble antigens. A selective loss of memory T cells was recently found in early stages of human immunodeficiency virus (HIV) infection, which could contribute to the qualitative defects observed in HIV-infected patients. In order to investigate whether HIV infection could induce an alteration in the process of differentiation from naive cells to cells with a memory phenotype, we studied the expression of CD45RA and CD45RO in CD4+ and CD8+ lymphocytes, by flow cytometric analysis, after mitogenic stimulation of mononuclear cells from patients with HIV infection. These preliminary results suggest that after in vitro activation the CD4+ and CD8+ populations from HIV-infected patients lose the CD45RA marker and concomitantly acquire the CD45RO determinant in the same way as shown for the healthy control population studied simultaneously. Thus, it appears that an alteration in the process of conversion of CD45RA into CD45RO does not contribute to the defects observed in the memory T-cell population in HIV infection.

Adult↗
PubMed1987

Monoclonal antibodies to synaptic macromolecules of Drosophila melanogaster.

We have obtained monoclonal antibodies to Drosophila acetylcholinesterase, glutamate dehydrogenase as well as other unknown macromolecules which may have some relevance in synaptic function. The majority of antibodies against acetylcholinesterase recognised common epitopes on all four subunits--but one (MA2) was specific to a 110 kDa dimer. Antibodies to unknown synaptic macromolecules were identified by their selective staining in immunofluorescence studies. F2A3 stains sensory neurons and their synapses in the visual and olfactory systems.

Acetylcholinesterase↗
PubMed1985

Genetic heterogeneity at the glucose-6-phosphate dehydrogenase locus in southern Italy: a study on the population of Naples.

Glucose-6-phosphate dehydrogenase (G6PD) electrophoretic phenotype was determined in red cells from 979 male subjects born in Naples (Southern Italy). In 0.7% of the cases no activity could be detected in haemolysates, while in 1.3% of the cases G6PD activity was approximately 20% of normal and electrophoretic mobility was altered. Moreover in two subjects a G6PD with altered mobility and normal activity was shown. G6PD was characterized in 10 subjects with variant phenotype. We conclude that the G6PD(-) phenotype in the population of Naples consists of at least six different G6PD variants associated with mild deficiency and at least one, G6PD Mediterranean, associated with severe deficiency.

Erythrocytes↗
PubMed1985

The cell lineage of the muscles of the Drosophila head.

Using a cell marker mutation the cell lineage of the muscles of the Drosophila head are traced out. Three sets of muscles separated by lineage restrictions are observed, even when cells are marked as early as the blastoderm stage. Each set underlies the derivatives of one of the three pairs of imaginal discs which differentiate to form the epidermis of the adult head. Clones of the homoeotic mutation engrailed (en10) were apparently normal in the muscles of the head. The muscle clone frequency, at the blastoderm stage, in each hemisegment of the fly is similar, indicating an equal partitioning of cells during segmentation.

Animals↗
PubMed1983

Increased methyl esterification of membrane proteins in aged red-blood cells. Preferential esterification of ankyrin and band-4.1 cytoskeletal proteins.

The enzymatic carboxyl methyl esterification of erythrocyte membrane proteins has been investigated in three different age-related fractions of human erythrocytes. When erythrocytes of different mean age, separated by density gradient centrifugation, were incubated under physiological conditions (pH 7.4, 37 degrees C) in the presence of L-[methyl-3H]methionine, the precursor in vivo of the methyl donor S-adenosylmethionine, a fourfold increase in membrane-protein carboxyl methylation was observed in the oldest cells compared with the youngest ones. The identification of methylated species, based on comigration of radioactivity with proteins stained with Coomassie blue, analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, shows, in all cell fractions, a pattern similar to that reported for unfractionated erythrocytes. However in the membrane of the oldest erythrocytes the increase in methylation of the cytoskeletal proteins, bands 2.1 and 4.1, appears to be significantly more marked compared with that observed in the other methylated polypeptides. Furthermore the turnover rate of incorporated [3H]methyl groups in the membrane proteins of the oldest cells markedly increases during cell ageing. Particularly in band 4.1 the age-related increase in methyl esterification is accompanied by a significant reduction of the half-life of methyl esters. The activity of cytoplasmic protein methylase II does not change during cell ageing, while the isolated ghosts from erythrocytes of different age show an age-related increased ability to act as methyl-accepting substrates, when incubated in presence of purified protein methylase II and methyl-labelled S-adenosylmethionine, therefore the relevance of membrane structure in determining membrane protein methylation levels can be postulated. Finally the possible correlation of this posttranslational protein modification with erythrocyte ageing is discussed.

Adult↗