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F Salvatore

Publications and source records attributed to F Salvatore.

At least 109 records · Page 6Linked to original sources
PubMed1988

Improved procedure for measuring gamma-glutamyltransferase isoenzymes in serum.

In this electrophoretic procedure for measuring isoenzymes of gamma-glutamyltransferase, patterns obtained are highly reproducible and the analytical imprecision (CV) ranges from 1.10% to 6.17%. A cellulose acetate support is used, at 220 V for 40 min. Sharply resolved isoenzyme bands were made visible by fluorescence scattered light, formed by use of a coumarin derivative as donor substrate. Two bands were observed for sera from normal subjects; four bands were variably present in sera from patients with different hepatobiliary diseases. Detection of the latter was satisfactory, down to a total activity in serum of 8-10 U/L. Three of the pathological bands were associated with low- and (or) very-low-density lipoproteins, whereas a major fraction of one of the normal bands in cirrhotic sera precipitated with high-density lipoprotein. The bands in normal sera, and one of the abnormal bands, did not.

Biliary Tract Diseases↗
PubMed1987

A new human species of aldolase A mRNA from fibroblasts.

A full-length cDNA aldolase A clone was isolated from a human fibroblast cDNA library and completely sequenced. Excluding the poly(A) tail, the clone covers 1095 base pairs (bp) of the coding region, plus 199 bp downstream for the termination codon and 146 bp upstream for the initiation codon, within a total of 1440 bp. Primer extension experiments performed with human cultured fibroblast mRNA indicate an elongated product of a further 40 bp. These results evaluated together with those obtained in a concurrent study concerning aldolase A mRNA isolated from human liver are direct evidence of aldolase A mRNA multiplicity in man. The data also suggest the existence in mammals of three different classes of aldolase A mRNA, which would account for tissue specificity and resurgence of foetal expression in tumors.

Amino Acid Sequence↗
PubMed1987

Mapping of a restriction fragment length polymorphism within the human aldolase B gene.

Peripheral blood DNA was hybridized to the full-length cDNA and the cloned structural gene of human aldolase B. With PvuII endonuclease a restriction fragment length polymorphism was detected that was present in the heterozygous state in about 21% of the individuals tested. A map of the human aldolase gene was constructed for the two groups of individuals found to produce different fragments after PvuII digestion. This allowed the localization of the polymorphic site within the gene, which was found to be due to the loss of a PvuII site in the last intron upstream from the 3' end. This polymorphism may be used as a genetic marker to study individuals affected by hereditary fructose intolerance.

Chromosome Mapping↗
PubMed1986

Structure and expression of mouse aldolase genes. Brain-specific aldolase C amino acid sequence is closely related to aldolase A.

Brain-specific aldolase C amino acid sequence (greater than 75% of the coding region) was determined for the first time. Two cDNA clones, pAM1 and pAM2, were identified, from a mouse brain library, by using human aldolase B cDNA as a probe. The larger one, pAM2, identified as a cDNA for aldolase C, has been completely sequenced and covers the 5'-untranslated region of the mRNA and the codons for amino acids 1-227 of the protein. The sequence indicates that aldolase C is more akin to aldolase A than to aldolase B. A cDNA library from mouse muscle was also screened, allowing the identification of clones pAM3 and pAM4, which contain cDNAs for aldolase A. The sequence obtained from pAM3 covers 70% of the coding sequence (amino acids 99-355) from the -COOH part of the protein. The cDNAs for the three aldolases, A, B and C, have been hybridized to RNA from various rat tissues. The results confirm the tissue specificity of the expression of the mRNA for the different isoenzymes and support the hypothesis that aldolase C expression, as aldolase A and B, is regulated at the transcriptional level or, in any case, via mRNA concentration.

Amino Acid Sequence↗
PubMed1985

Pseudouridine excretion and transfer RNA primers for reverse transcriptase in tumors of retroviral origin.

To evaluate the relationship between pseudouridine increase in biological fluids and retroviral cell transformation, we have studied the effect of retrovirus infection and/or transformation on the rate of pseudouridine excretion by chick embryo fibroblasts. The results show that: pseudouridine excretion by chick embryo fibroblasts transformed by Rous sarcoma virus is several times higher than that of normal cells; this increased excretion precedes by many hours the appearance of the morphological signs of transformation and it is always present when neosynthesized infectious viral particles are released into the culture medium; and pseudouridine excretion was also increased in cells infected by a mutant of Rous sarcoma virus (RAV-1) which, lacking the src gene, does not transform the cells but replicates normally. To investigate if pseudouridine overproduction is related to an altered turnover rate of specific transfer RNA (tRNA) species which functions as primer of retrovirus reverse transcriptase, the concentration of non-acylated proline-accepting tRNA and non-acylated tryptophan-accepting tRNA, primers of reverse transcriptase of murine leukemia virus and of Rous sarcoma virus, respectively, has been measured, the former in normal and transformed AKR thymus and the latter in normal fibroblasts and in fibroblasts infected by Rous sarcoma virus or by its nontransforming mutant. The results show that in both systems a significant increase of the primer tRNA species occurs in the infected or transformed cells.

Animals↗
PubMed1985

Application of a statistical approach to determining reference intervals in clinical chemistry.

In clinical chemistry a linear-regression model may be used to determine reference intervals. A crucial point in this approach is the choice of variables to introduce into the model. In the present paper, we have applied a nonautomatic selection procedure, known as "element analysis," to a sample of 126 individuals from a small, ethnically homogeneous community in southern Italy. We investigated the effects of four independent variables--sex, age, weight, and alcohol consumption--on values for serum urea. Only sex and age proved to affect the urea values and were therefore introduced into the final model. This approach may be useful in determining reference intervals from observational studies when it is difficult to control a priori relevant factors. Moreover, variables may be selected not only on the basis of statistical criteria, but also according to biochemical and medical criteria.

Adolescent↗
PubMed1984

The complete sequence of a full length cDNA for human liver glyceraldehyde-3-phosphate dehydrogenase: evidence for multiple mRNA species.

A recombinant M13 clone (O42) containing a 65 b.p. cDNA fragment from human fetal liver mRNA coding for glyceraldehyde-3-phosphate dehydrogenase has been identified and it has been used to isolate from a full-length human adult liver cDNA library a recombinant clone, pG1, which has been subcloned in M13 phage and completely sequenced with the chain terminator method. Besides the coding region of 1008 b.p., the cDNA sequence includes 60 nucleotides at the 5'-end and 204 nucleotides at the 3'-end up to the polyA tail. Hybridization of pG1 to human liver total RNA shows only one band about the size of pG1 cDNA. A much stronger hybridization signal was observed using RNA derived from human hepatocarcinoma and kidney carcinoma cell lines. Sequence homology between clone 042 and the homologous region of clone pG1 is 86%. On the other hand, homology among the translated sequences and the known human muscle protein sequence ranges between 77 and 90%; these data demonstrate the existence of more than one gene coding for G3PD. Southern blot of human DNA, digested with several restriction enzymes, also indicate that several homologous sequences are present in the human genome.

Adult↗
PubMed1984

Isolation and nucleotide sequence of a full-length cDNA coding for aldolase B from human liver.

Two recombinant clones, pA2 and pA3, containing cDNA sequences for human aldolase B have been isolated from a full length human liver cDNA library. The larger one, pA3, has been subcloned in M13 phage and completely sequenced with the chain terminator method. The sequence covers 1,600 nucleotides including the whole coding region (1,050 nucleotides), 67 nucleotides from the 5' non-coding region and the whole 3' non-coding region, 440 nucleotides long, down to the poly-A tail. Comparison with rabbit aldolase A and with a partial sequence of rat aldolase B, shows a homology of about 76% for aldolase A and of about 94% for aldolase B, which indicates that the sequenced cDNA codes for the liver isoenzyme. This is the first complete sequence reported for human aldolase B. The pA3 clone strongly hybridizes to 18S mRNA from human adult liver as expected from the size of the isolated cDNA.

Amino Acid Sequence↗
PubMed1984

Determination of pseudouridine in tRNA and in acid-soluble tissue extracts by high-performance liquid chromatography.

A high-performance liquid chromatographic method to measure pseudouridine and other nucleosides in hydrolyzed unfractionated tRNA and in acid soluble tissue extracts is described. The method is based on the following steps: tRNA extraction and hydrolysis by a mixture of ribonuclease A, snake venom phosphodiesterase and bacterial alkaline phosphatase; nucleoside purification (in the case of acid soluble tissue extract) by affinity chromatography on a phenyl-boronate gel column; nucleoside separation and quantitation by high-performance liquid chromatography on an octadecylsilane column by a reversed polarity gradient elution. The procedure allows a very accurate quantitation of pseudouridine and some other nucleosides, and its sensitivity is such that only 20 micrograms of tRNA are required. The method has been utilized to compare the pseudouridine content of hydrolyzed tRNA extracted from normal and lymphomatous murine thymus, as well as the pseudouridine content in acid soluble extracts from the same tissues.

Animals↗
PubMed1984

Serum pseudouridine as a biochemical marker in the development of AKR mouse lymphoma.

Pseudouridine is a modified nucleoside derived from the degradation of some species of RNA, primarily transfer RNA, the level of which is elevated in biological fluids of tumor-bearing subjects. In order to study the relationship between pseudouridine levels and the development and progression of neoplasia, we have measured pseudouridine levels in the serum of inbred mice with high (AKR) and low (BALB/c) incidence of spontaneous lymphoma and in mice carrying transplantable lymphoid tumors. Our results show that the serum level of pseudouridine: (a) in healthy mice, is higher in females than in males; (b) increases significantly in female AKR mice in the period preceding the development of lymphoma (preneoplastic period occurring at about 6 months of age); and (c) is highest in AKR mice with lymphoma, the most elevated levels being found in mice with widely disseminated disease. The latter observation was confirmed by experiments with a transplantable AKR lymphoma (T2), where a positive correlation between tumor burden and serum pseudouridine levels was found. On the contrary, in BALB/c mice carrying a transplantable myeloma tumor (MOPC-460), no increase was seen despite the presence of a considerable tumor burden. The increase of pseudouridine in the preneoplastic period, in the absence of overt disease is viewed as an early sign of the development of the disease.

Animals↗
PubMed1983

Determination of pseudouridine and other nucleosides in human blood serum by high-performance liquid chromatography.

A specific, sensitive, and rapid method to measure pseudouridine in human blood serum is described. The method is based on the following steps: (i) deproteinization of serum samples by filtration on membrane cones or by acetonitrile; (ii) purification of nucleosides and concentration of the sample by affinity chromatography on phenylboronate gel followed by lyophilization; and (iii) separation of nucleosides and their quantitation by reverse-phase high-performance liquid chromatography. The pseudouridine mean value in 30 normal subjects was 2.52 +/- 0.28 nmol/ml. The procedure also allows the identification of inosine, uridine, guanosine, and adenosine. Nevertheless, the presence in human blood serum of enzymatic activities which convert adenosine to inosine and cytidine to uridine prevents the precise quantitation of these nucleosides. All the compounds were identified by comparing their retention times and absorbance ratios (A280/A254) with those of pure compounds, as well as by cochromatography.

Chromatography, High Pressure Liquid↗
PubMed1983

Cloning of several cDNA segments coding for human liver proteins.

A human cDNA library was constructed using M13 derivative vectors. The simple and rapid procedures for sequencing single-stranded DNA by the dideoxy chain termination method allowed a screening of individual clones directly by DNA sequence analysis. Some of these clones were identified as coding for: serum albumin, alpha1-antitrypsin, retinol-binding protein, prothrombin, haptoglobin, and metallothionein. Furthermore, a clone coding for aldolase B was tentatively identified on the basis of high sequence homology with rabbit muscle aldolase.

Amino Acid Sequence↗
PubMed1983

Modified nucleosides in body fluids of tumor-bearing patients.

The catabolism of nucleic acids, particularly tRNA, produces a variety of modified nucleosides which are not reutilized by mammalian cells. Investigation of these compounds in body fluids, mainly urine, has recently provided evidence of altered metabolic situations in tumor-bearing patients. The factors involved in the alterations of modified nucleosides formation are connected with altered tRNA-modifying enzymes and/or altered turnover of subpopulations of tRNA. A common pattern in tumor cells or tissues is the presence of isoaccepting tRNA species containing aberrant nucleoside modifications. Several modified nucleosides have been detected and quantitated by HPLC analysis of the urine of normal subjects and cancer patients. Results obtained, in the authors' laboratory, among others, indicate a possible correlation between urinary excretion of these compounds and the course of the disease, with implications for the follow-up of therapeutic treatment. Particular reference should be made to psi, which appears to be a suitable marker for monitoring these subjects. The data from the authors' laboratory also show that the analysis of modified nucleosides in blood may be considered a useful tool in the search for proper markers associated with the cancer status. In this respect psi is suggested as a biochemical indicator for cancer patients.

Chromatography, High Pressure Liquid↗
PubMed1983

Isolation and characterization of a tRNA(guanine-7-)-methyltransferase from Salmonella typhimurium.

The tRNA modifying enzyme, S-adenosylmethionine:tRNA(guanine-7-)-methyltransferase, has been extensively purified from Salmonella typhimurium. A rapid and efficient purification method using phosphocellulose chromatography followed by ammonium sulfate precipitation and Sephadex G-100 gel filtration is described. The enzyme appears to be a single polypeptide chain with a molecular weight of approximately 25 000--30 000 daltons. The Km for S-adenosylmethionine and for undermethylated tRNA is 53 microM and 3.4 microM, respectively. The methylation reaction is dependent on added monovalent or divalent cations; 5 mM spermidine, 3 mM MgCl2 and 1 mM spermine are the most effective. The enzyme, though not homogeneous, is free from contaminating ribonucleases and other tRNA methyltransferases.

Chromatography, Gel↗
PubMed1983

Pseudouridine determination in blood serum as tumor marker.

A new method to measure pseudouridine (psi rd) in blood serum has been used to study patients with cancer of breast, lung, colon, and ovaries, and patients with hepatomas, non-Hodgkin lymphomas, and acute lymphoblastic leukemias, at different stages. The results indicate: (1) a significant (p less than 0.01) difference between the psi rd serum level of the cancer patient group and the normal control group; (2) that the increase of the level of serum psi rd is correlated both to the stage of the disease and to the spreading of the tumor tissue; (3) a correlation between the response to therapy and the behaviour of psi rd serum levels.

Breast Neoplasms↗