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Biomedical subjects

S Ferrari

Publications and source records attributed to S Ferrari.

At least 325 records · Page 18Linked to original sources
PubMed1988

Growth factor regulation of the promoter for calcyclin, a growth-regulated gene.

The steady-state levels of calcyclin mRNA are regulated by growth factors. Using deletion mutants of the 5'-flanking region and a linked reporter (the bacterial chloroamphenicol transferase gene), we have investigated the elements of the calcyclin gene's promoter that respond to growth factors. By a transient expression assay after transfection in BALB/c/3T3 cells, we have been able to show that the serum-inducible sequences are contained in a 164-base pair fragment just upstream of the cap site. This fragment also contains an enhancer, and responds to platelet-derived growth factor as well as to serum. The sequences from -1371 to -1194 upstream of the cap site contain an element which is negatively regulated by epidermal growth factor. These findings have been confirmed in hamster cell lines in which the deletion mutants of the calcyclin promoter controlled the expression of the cDNA for human thymidine kinase. These results indicate that, like in other growth-regulated genes the activity of the calcyclin promoter is modulated by both positive and negative elements. Even more intriguing, though, is the finding that some of these negative elements may be influenced by growth factors in the environment.

Animals↗
PubMed1988

Expression of c-myc and induction of DNA synthesis by platelet-poor plasma in human diploid fibroblasts.

When WI-38 human diploid fibroblasts become confluent, they stop synthesizing DNA and dividing. Addition of serum causes the quiescent cell to reenter the cell cycle. Prolonged quiescence after confluence decreases and delays the response to serum. For a few days after reaching confluence, WI-38 cells also respond to platelet-poor plasma. During this period, although not cycling, WI-38 cells still express c-myc and other growth-regulated genes, as measured by steady-state RNA levels. If the quiescence is prolonged further, c-myc expression (and that of two other growth-regulated genes) is no longer detectable, and its disappearance coincides with a loss of response to platelet-poor plasma. These results suggest that, also under physiological conditions, the expression of c-myc and other growth-regulated genes can cooperate with platelet-poor plasma in inducing cellular DNA synthesis in human diploid fibroblasts.

Blood Platelets↗
PubMed1988

Olive-oil-enriched diet: effect on serum lipoprotein levels and biliary cholesterol saturation.

The effect of diet enriched with a monounsaturated fatty acid (olive oil) on serum lipoproteins, biliary cholesterol saturation index, and gallbladder motility compared with a standard low-fat diet was evaluated in 11 young volunteers admitted to a metabolic ward. A significant decrease of mean total cholesterol (-9.5%), total apo B (-7.4%), LDL cholesterol (-12.2%), and total triglycerides (-25.5%) was observed after the olive-oil-enriched diet. Total HDL- and HDL-subfractions-cholesterol levels as well as serum apo A-I mean levels remained unchanged. Cholesterol saturation index of the bile and fasting and after-meal gallbladder volumes were unaffected by the enriched diet as compared with the low-fat diet. Olive oil may be a natural fat that can be used for the control of plasma and LDL cholesterol as a valid alternative to polyunsaturated fatty acids.

Adult↗
PubMed1988

Myeloperoxidase gene expression in blast cells with a lymphoid phenotype in cases of acute lymphoblastic leukemia.

By using a cDNA clone of the myeloperoxidase (MPO) gene, we have studied, by Northern blot analysis, the level of MPO mRNA in eight cases of acute lymphoblastic leukemia (ALL). The blast cell populations studied were characterized by morphologic, cytochemical, immunochemical, and molecular criteria. With all the methods used the populations were found to be highly homogeneous and showed a typical lymphoid phenotype. In particular, the Ig heavy-chain gene rearrangement was largely prevalent, and the germ line configuration was almost absent. However, in three of eight cases, high levels of MPO mRNA were detected. The remarkable homogeneity of the cell populations examined suggests that the MPO mRNA observed was present in cellular elements certainly identified as lymphoid. The absence of contamination by myeloid cells was confirmed by the results of Western blot analysis of the proteins of the cell population studied: no MPO protein was detectable. The levels of mRNA observed were high enough to be comparable to those observed in a promyelocytic cell population.

Cell Transformation, Neoplastic↗
PubMed1988

[Possible effects of lead on various hormonal metabolic pathways].

After reviewing the principal studies on the interferences of lead on the endocrine system, this paper reports the results of a survey carried out on 30 subjects in which the effects of lead on serum FSH, LH and testosterone and on urinary steroid hormones excretion were examined. Statistically significant differences were not demonstrated between lead exposed subjects and control group for serum LH and testosterone (total and free) and for urinary steroids. A significant increase of FSH has been detected in lead exposed workers even if this increase remains between the "normal limits" of the laboratory which performed the determinations. The results are discussed in the light of the more recent knowledge about the endocrine effects of xenobiotics in general and heavy metals in particular and some interpretations to justify the detected FSH increase are proposed.

17-Hydroxycorticosteroids↗
PubMed1988

Expression of oncogenes and cell cycle related genes in acute and chronic leukemias.

The authors have assayed the level of expression of several cell-cycle related genes in several populations of circulating myeloid leukemic blast cells. The genes explored included oncogenes such as c-myc, c-myb, p53, and cell-cycle-related genes such as vimentin, calcyclin, ornithine decarboxylase (ODC) and histone H3. Particular attention was given to analysis of the relationship existing between the mRNA levels of the histone H3 gene, which is expressed specifically in the S phase of the cell cycle, and the levels of other genes that are expressed in different stages of the G1 phase. Remarkable differences were observed among the different cases indicating that a differential expression of cell-cycle-related genes characterizes many acute leukemias. This differential expression is reflected in an altered ratio among G1-related genes and the H3 histone gene. The large fraction of leukemic cells which does not express histone H3 and therefore is functionally noncycling, shows a heterogeneous pattern of G1-related gene expression. This reflects the inability of most leukemic cells to progress through the G1 phase into the S phase of the cell cycle. This inability represents an abnormality of the cell cycle. It is concluded that the study of the expression of cell-cycle genes and protooncogenes in in understanding how leukemic cells enter a state of proliferation arrest, which appears to occur in a large fraction of leukemic cells.

Cell Cycle↗
PubMed1988

Effects of dietary fish oil on malondialdehyde production and glutathione peroxidase activity in hyperlipidaemic patients.

In 20 adult patients suffering from hyperlipidaemia we measured the lipid composition of erythrocyte membrane, the glutathione peroxidase activity in both erythrocytes and platelets, the production of malondialdehyde by platelets stimulated with thrombin, as well as the level of plasma selenium, retinol and alpha-tocopherol, before and after 8 weeks of fish oil supplementation (20 ml daily). We noted a remarkable reduction in plasma triglycerides which was associated with a significant decrease in blood pressure; moreover, we noted a reduction in the amount of arachidonic acid compensated by an increment of omega-3-fatty acid (particularly eicosapentaenoic and docosahexaenoic acids). The dietary supplementation with fish oil was associated with a significant increase in glutathione peroxidase activity in both erythrocytes and platelets. On the contrary, the production of malondialdehyde, which was originally higher than normal in hyperlipidaemics, was inhibited significantly after fish oil (p less than 0.001). Whereas no changes were observed in the concentration of plasma selenium and alpha-tocopherol, an increment of plasma retinol occurred. These data indicate that in hyperlipidaemics there is a proaggregant status; this situation may be normalized by using a dietary supplementation of fish oil; the increase of polyunsaturated fatty acids on the cell membrane, with a possible increment of the formation of lipoperoxides, induced by fish oil, is compensated by an increased activity of the scavenger enzyme glutathione peroxidase.

Adult↗
PubMed1988

Effect of protein-restricted diet on serum lipids and atherosclerosis risk factors in patients with chronic renal failure.

Early changes in lipid metabolism and appearance of atherosclerosis risk factors play a key role in the development of cardiovascular disease of chronic renal failure (CRF). In the effort to evaluate the effects of protein restricted diet on dyslipidemia, we studied 122 patients with CRF (S-creatinine 1.3-9 mg/dl); 58.2% of whom were on antihypertensive drugs treatment. Patients had been separated into 6 groups: group 1 was kept on a free diet; groups 2, 3, 4, 5, 6 were kept on a protein-restricted diet from 12, 24, 36, 48, 60 months, respectively. We found hypertriglyceridemia, pathologic levels of esterified cholesterol in high density lipoprotein (HDL-C) and pathologic apolipoprotein A1/B ratio in group 1; the comparison with other groups--whose values were normal range after 12, 24 months of treatment--showed significant differences. The lipidic parameters were independent of the duration of CRF and of patients' age. Serum creatinine showed a significant correlation with tryglicerides and HDL-C values only in group 1. Total cholesterol and apolipoprotein B were significantly greater in hypertensives than in normotensives. In our opinion, a moderate restriction in protein intake could be effective in preventing and in halting the early alterations of lipid metabolism in CRF.

Adult↗
PubMed1987

Membrane polyunsaturated fatty acids and lithium-sodium countertransport in human erythrocytes.

Two groups of individuals, 26 normotensive normolipemic and 37 normotensive hyperlipemic, all without family history of hypertension have been selected in attempt to demonstrate whether Li-Na countertransport of erythrocytes is influenced by plasma and membrane lipid composition. The maximal rate of Li-Na countertransport was elevated in hyperlipemics (0.344 +/- 0.168 vs 0.220 +/- 0.074 mmol/l erythrocytes/h). This difference is highly significant. Hyperlipemics had different composition of membrane lipids than normals. The most important variations were: increase of palmitic, palmitoleic and total saturated fatty acids (SFA) as well as increase of cholesterol/phospholipids ratio (C/PL); in contrast, hyperlipemics had a reduced amount of linoleic acid and total unsaturated fatty acids (UFA) as well as total polyunsaturated fatty acids (PUFA). Consequently, UFA/SFA and PUFA/SFA ratios were lower than in normals. Li-Na countertransport was negatively correlated with the amount of PUFA (P less than 0.02), whereas it was positively correlated with the following parameters: oleic/linoleic ratio (p less than 0.02), monounsaturated fatty acids/polyunsaturated fatty acids ratio (p less than 0.03) as well as with the SFA + monounsaturated fatty acid/PUFA ratio (p less than 0.03). These findings suggest that the V max of Li-Na countertransport in erythrocytes is influenced by the lipid composition of the membrane.

Adult↗
PubMed1987

Structural and functional analysis of a growth-regulated gene, the human calcyclin.

Calcyclin was originally defined as a cDNA clone (2A9) whose cognate RNA is growth-regulated and whose sequence shows strong similarities to the sequences of the S-100 protein, a calcium-binding protein, as well as to a subunit of the major cellular substrate for tyrosine kinase. Using the full-length cDNA, we have now isolated from a human genomic library several phages containing calcyclin sequences. One of the phages, ch. 28-10, contains the entire calcyclin gene, plus extensive flanking sequences. The calcyclin gene is a unique copy gene and has 3 exons. The 5' flanking sequence has been characterized, both structurally and functionally. Besides a TATA box, it contains, in the region proximate to the cap site, GC boxes and a sequence with a strong homology to the enhancer core of the SV40 promoter. Other enhancer-like elements are found scattered in both the 5' and 3' flanking regions. The proximate 5' flanking region is very active in driving the transient expression of linked reporters in transfection experiments. Finally, the calcyclin gene has been localized to the long arm of human chromosome 1, near the ski oncogene.

Base Sequence↗
PubMed1987

Phosphorylation of protamines by protein kinase C: involvement of sites which are phosphorylated in vivo and are not affected by cAMP-dependent protein kinase.

Most fish protamines contain two phosphorylatable sites both of which incorporate phosphate in vivo. Here we show that in two protamines (salmine A1 and clupeine Y1) the site more distant from the N-terminus (residues 20-21) is unaffected by cAMP-dependent protein kinase while it represents the main target for protein kinase C. Such a phosphorylation is typically independent of Ca2+ and phospholipids: responsiveness to these effectors however is conferred by previous fragmentation of protamine with thermolysin. These results suggest that Ca2+, phospholipid-independent phosphorylation of protamine by protein kinase C might have physiological relevance and shed light on the structural basis for the specificity of such an unique process.

Amino Acid Sequence↗
PubMed1987

Molecular cloning of a cDNA for a human ADP/ATP carrier which is growth-regulated.

We have identified in a human cDNA library a clone (hp2F1) whose cognate RNA is growth-regulated. The insert has been sequenced and the nucleotide sequence shows a strong homology to the nucleotide sequences of the ADP/ATP carrier cDNA and gene, respectively, isolated from Neurospora crassa and Saccharomyces cerevisiae. The putative amino acid sequence of hp2F1 shows an 87% homology to the amino acid sequence of the ADP/ATP carrier from beef heart mitochondria. We conclude that the insert of hp2F1 contains the full coding sequence of a human ADP/ATP carrier. The steady-state RNA levels of the ADP/ATP carrier are growth-regulated. They increase when quiescent cells are stimulated by serum, platelet-derived growth factor, or epidermal growth factor, but not by platelet-poor plasma or insulin. RNA levels of the ADP/ATP carrier decrease instead when growing HL-60 cells are induced to differentiate by either phorbol esters or retinoic acid.

Amino Acid Sequence↗
PubMed1987

Ca2+ phospholipid-dependent and independent phosphorylation of synthetic peptide substrates by protein kinase C.

Several synthetic peptides reproducing fragments of protamines have been used as model substrates for Ca2+/phospholipid-dependent protein kinase C, tested both in the absence of any effector (basal conditions) and upon activation by either Ca2+ and phosphatidylserine (or diacylglycerol) or limited proteolysis. Only the peptide Arg4-Tyr-Gly-Ser-Arg6-Tyr [Ga(52-65)] shares the unique property of protamines of being readily phosphorylated even under basal conditions. Optimal activity in the absence of effectors is observed with Tris/HCl buffer pH 7.5; Pipes and Hepes are less effective at pH 7.5, and at pH 6.5 basal phosphorylation is reduced. Under the best conditions for basal phosphorylation of Ga(52-65), its derivative with ornithine replaced for arginine and those corresponding to its C-terminal fragments Gly-Ser-Arg6-Tyr [Ga(57-65)] and Gly-Ser-Arg3 [Ga(57-61)], as well as the peptides Pro-Arg5-Ser2-Arg-Pro-Val-Arg [Th(1-12)], Arg4-Tyr-Arg2-Ser-Thr-Val-Ala [Th(13-23)] and Arg2-Leu-Ser2-Leu-Arg-Ala are not significantly affected though all of them, like histones, are more or less readily phosphorylated upon activation of protein kinase C by Ca2+/phosphatidylserine. The peptide Ser2-Arg-Pro-Val-Arg [Th(7-12)] however, corresponding to the C-terminal part of Th(1-12), is not phosphorylated even in the presence of activators. Limited proteolysis can roughly mimic the Ca2+/phosphatidylserine effect inducing however different extents of activation depending on the nature of the peptide substrates. Our results support the following two conclusions. Basal phosphorylation by protein kinase C in the absence of any effector requires peptide substrates whose target residue(s) are included between two extended arginyl blocks and is also dependent on pH and nature of the buffer. Peptides having extended clusters of either arginyl or ornithyl residues on the C-terminal side of serine are also readily phosphorylated, but they need activation of protein kinase by either Ca2+/phosphatidylserine or limited proteolysis. The same is true of peptides having basic residues only on the N-terminal side, or even on both sides but in limited number.

Amino Acid Sequence↗