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N Russo

Publications and source records attributed to N Russo.

At least 55 records · Page 3Linked to original sources
PubMed1994

Role of glutamine-117 in the ribonucleolytic activity of human angiogenin.

The crystal structure of human angiogenin (reported in the preceding paper in this issue) reveals that the site that corresponds to the pyrimidine binding site of RNase A is obstructed by Gln-117. Mutation of this residue to Ala and Gly is here found to increase activity 11- to 18-fold and 21- to 30-fold, respectively, toward dinucleotide, polynucleotide, and cyclic nucleotide substrates, but without changing specificity. The enhanced activity of Q117G toward CpA is due to a 5-fold decrease in Km and a 6-fold increase in kcat. Its Ki value for 2'-CMP is 5-fold lower than that of native angiogenin, whereas its Ki value for 5'-AMP is unchanged. It has been reported previously that mutating Asp-116 to Ala increases activity 15-fold. The double mutant D116A/Q117A is shown to be only slightly more active than each individual mutant. The present results demonstrate that Gln-117 impedes the ribonucleolytic activity of angiogenin, as predicted by x-ray crystallography. Moreover, they suggest that prior to or during catalysis angiogenin must undergo a conformational change to reorient the C-terminal segment that contains this residue, and that a similar reorganization is required for the mutants as well. This view is supported by molecular modeling of an angiogenin-uridine vanadate complex. These in vitro findings have implications for the angiogenic activity of angiogenin in vivo.

Base Sequence↗
PubMed1993

Expression in mammalian cells, purification and characterization of recombinant human pancreatic ribonuclease.

A synthetic cDNA coding for human pancreatic RNase, equipped with a secretion signal sequence, was cloned and stably expressed in Chinese hamster ovary cells. The recombinant RNase, secreted into the culture medium, was purified and characterized. It was found to be indistinguishable, by structural and catalytic parameters, from the enzyme isolated from human pancreas. Furthermore, the glycosylated forms were separated from the non-glycosylated form. Up until now, human RNases have been isolated only in small amounts from autopic specimens. This has hindered the exploitation of a human RNase for the construction of immunotolerated immunotoxins. On the other hand, the availability of an effective system for the expression of a human RNase may render feasible the transfer, by protein engineering, of the interesting pharmacological actions of non-human RNase [1993 Trends Cell Biol. 3, 106-109] to an immunotolerated, human RNase.

Amino Acid Sequence↗
PubMed1993

Expression of bovine seminal ribonuclease in Escherichia coli.

Bovine seminal RNAase (BS-RNAase), an unusually dimeric member of the pancreatic-like ribonuclease superfamily, is also a multifunctional biological effector, with antitumor, immunosuppressive, and antispermatogenic activities. We report here the cloning of a semi-synthetic cDNA coding for the protein subunit chain, its expression with a T7 expression system in Escherichia coli inclusion bodies, the dimerization of correctly reoxidized monomeric protein, followed by the purification in high yields of the recombinant enzyme, and by its conversion to a protein undistinguishable from BS-RNAase as isolated from seminal vesicles, both in its catalytic activity and in the micro-heterogeneity of its quaternary structure.

Animals↗
PubMed1993

Expression of native dimers of bovine seminal ribonuclease in a eukaryotic cell system.

Bovine seminal ribonuclease, a uniquely dimeric pancreatic-like RNase, with its dimeric structure stabilized by two intersubunit disulfides, and endowed with special, i.e. non-catalytic, actions (antitumor, immunosuppressive, antispermatogenic), was stably expressed in Chinese hamster ovary cells. The recombinant protein, secreted in the culture medium as a correctly folded dimeric enzyme, was purified to homogeneity and found to be fully active both in its catalytic and antitumor activities.

3T3 Cells↗
PubMed1992

Serum neopterin levels in patients with hepatocellular carcinoma.

Increased concentrations of neopterin have been found in conditions causing a stimulation of cellular immunity, including various malignancies. In liver diseases, serum or urinary neopterin levels have been studied in acute viral hepatitis, chronic hepatitis, fatty liver and liver cirrhosis. In the present study neopterin serum levels have been measured in 16 patients with hepatocellular carcinoma (HCC), in 32 patients with liver cirrhosis, and in 28 healthy subjects as controls. Mean values of serum neopterin were significantly increased (p < 0.01) in patients with HCC (15.89 +/- 6.34 nmol/l) when compared with those of normal subjects (4.74 +/- 2.13 nmol/l), but no difference was observed between patients with HCC (associated or not with liver cirrhosis) and patients with liver cirrhosis. Neopterin concentrations are not affected by liver cirrhosis aetiology, nor by its clinical severity, and are not correlated to the values of serum alpha-fetoprotein, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl-transferase, and gamma-globulin. The results show that there is a consistent overlap of values in patients with HCC and liver cirrhosis; macrophage activation seems to be a feature of chronic liver diseases, irrespective of HCC development.

Adult↗
PubMed1986

Ovarian and peripheral androgen and oestrogen levels in post-menopausal women: correlations with ovarian histology.

Ovarian and peripheral plasma levels of oestrone (E1), oestradiol (E2), androstenedione (A) and testosterone (T) were assayed in 58 post-menopausal women who underwent hysterectomy and oophorectomy (35 for endometrial carcinoma and 23 for benign gynaecological diseases). No significant difference between the two groups was seen when they were matched for percentage of ideal weight. However, significant differences were found between the ovarian and peripheral levels of the four steroids investigated. To facilitate analysis of the data, 40 of these women were classified into three groups (1, 2 and 3) according to degree of stromal hyperplasia of the ovary. Group 1 comprised those with atrophic ovaries, group 2 those with slight stromal hyperplasia and group 3 those with moderate or marked stromal hyperplasia. Ovarian levels of A and T were significantly higher than peripheral levels in all three groups, but the ovarian/peripheral oestrogen differences were significant only in groups 1 and 2. The ovarian steroid levels in group 3 were significantly higher than those in groups 1 and 2 in the cases of E1 (P less than 0.01), E2 (P less than 0.001) and A (P less than 0.001), but not in that of T. It was concluded that ovaries showing marked stromal hyperplasia can produce significant amounts not only of androgens but also of E2, and hence that any evaluation of the hormonal pattern in post-menopausal women must also take into account the microscopic characteristics of the ovary.

Adenocarcinoma↗
PubMed1984

Sequential resonance assignments in 1H NMR spectra of oligonucleotides by two-dimensional NMR spectroscopy.

A sequential assignment procedure is outlined, based on two-dimensional NOE ( NOESY ) and two-dimensional J-correlated spectroscopy ( COSY ), for assigning the nonexchangeable proton resonances in NMR spectra of oligonucleotides. As presented here the method is generally applicable to right-handed helical oligonucleotides of intermediate size. We applied it to a lac operator DNA fragment consisting of d( TGAGCGG ) and d( CCGCTCA ) and obtained complete assignments for the adenine H8, guanine H8, cytosine H6 and H5, thymine H6 and 5-methyl, and the deoxyribose H1', H2', H2", H3', and H4' resonances, as well as some H5', H5" (pairwise) assignments. These assignments are required for the analysis of two-dimensional NOE and J-coupling data in terms of the solution structure of oligonucleotides.

Hydrogen Bonding↗
PubMed1984

Ovarian and peripheral plasma levels of progestogens, androgens and oestrogens in post-menopausal women.

Ovarian and peripheral plasma concentrations of oestrone (E1), oestradiol (E2), androstenedione (A), testosterone (T), progesterone (P) and 17 alpha-hydroxy-progesterone (17 alpha OH-P) were assayed in 20 healthy post-menopausal women undergoing hysterectomy because of uterine fibromatosis. Significant differences were found between the ovarian and peripheral levels of E1 (P less than 0.01), E2 (P less than 0.001), A (P less than 0.01), T (P less than 0.001) and P (P less than 0.001). Analysis of the possible relationships between peripheral and ovarian levels of the six steroids considered and the patients' clinical characteristics revealed a positive correlation in only three cases, viz. between body weight and peripheral levels of E1 and E2, between E1 and E2 peripheral levels and between body weight and the E1/A ratio. The ovarian-peripheral gradient was calculated for each patient and was considered significant only if the ovarian peripheral difference exceeded the sum of each concentration multiplied by twice the maximal coefficient of variation of the assays used (12%). This gradient was significant in 75% of patients for T, in 45% for A, in 35% for E2, in 25% for E1, in 35% for P and in 30% for 17 17 alpha OH-P. Our findings confirm that circulating oestrogens in post-menopausal women originate mainly from the peripheral conversion of ovarian and adrenal androgens and that the ovary still continues to produce androgens. They also provide evidence that the ovary, at least in some post-menopausal subjects, can be a potential source of oestrogens and progestogens.

17-alpha-Hydroxyprogesterone↗
PubMed1981

[Diagnostic value of copper and magnesium in hemolymphopathies and solid tumors].

The value and development of the copper and magnesium have been examined in thirty-four patients whose eighteen were affected by malignant lymphomas (9 L.H. and 9 non-H.), fourteen by solid tumors and two by acute leukemias. Our results prove clearly a manifest increase of the copper in the lymphomas' patients, especially in the Hodgkin's disease, and in none patients a decrease. Analogous trend has been found in the 71% of the patients with solid tumors. Scarcely significant are the results obtained in the acute leukemias. Contrary to copper, the values of the magnesium are nothing at all expressive for a diagnostic "dépistage"; a light increase of the metal is observed only in the 55% of the lymphomas non-H., while in the cancers the values are very variable. Our results confirm what other Authors have already referred, i.e. the copper's value is of a large aiding for the determination and the valuation of the diseases' activity in the above related conditions.

Adolescent↗