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Biomedical subjects

M Romani

Publications and source records attributed to M Romani.

At least 55 records · Page 3Linked to original sources
PubMed1990

Preferential integration of the Ad5/SV40 hybrid virus at the highly recombinogenic human chromosomal site 1p36.

Human fibroblasts transformed with an adenovirus-5/simian virus 40 recombinant construct (Ad5/SV40) were analyzed to determine the chromosomal site(s) of virus integration. This was firstly done by in situ hybridization using metaphase and prometaphase chromosomes and 125I-labeled Ad5 DNA. Out of seven transformed cell lines (six of clonal origin and one uncloned), six were proven to have integrated the viral genome at the short- or the long-subtelomeric regions of autosome 1, two regions known to include chromosomal modification sites induced by acute infection with Ad12. Characterization of the integration sites was carried out by restriction analysis. Transformed cell lines with the same major chromosomal integration site were found to have the viral genome inserted in restriction fragments of different size, indicating that viral integration has occurred at different sites within a relatively small chromosomal region. Molecular studies carried out on one of the transformed cell lines (H13.1) gave an independent confirmation of the viral integration at the subterminal region of autosome 1 short arm. Nucleotide sequencing at this cellular-viral junction has shown that the virus has integrated within tandemly repeated Alu-like elements and that the cellular flanking sequences have several homologies with variable number of tandem repeats core sequences. Many possible open reading frames were identified in the DNA segment adjacent to the Alu-like elements.

Adenoviruses, Human↗
PubMed1989

Determinants of bile secretion: effect of bile salt structure on bile flow and biliary cation secretion.

The effect of five bile salts, deoxycholate, chenodeoxycholate, cholate, ursodeoxycholate, and ursocholate, possessing (in decreasing order) different hydrophobicity, on bile flow and biliary secretion of total calcium, magnesium, sodium, and potassium was studied in 10 patients with T-tubes. Each subject was infused intraduodenally with one or two bile salts, given separately, to produce a selective enrichment of biliary bile salts with the infused bile salt. The choleresis induced per 1-mumol increase of bile salt output was greater during the secretion of 7 beta-hydroxylated bile salts, ursodeoxycholate (0.029 ml), and ursocholate (0.027 ml), followed in decreasing order by deoxycholate (0.023 ml), chenodeoxycholate (0.019 ml), and cholate (0.009 ml). Deoxycholate stimulated the greatest increase in cation secretion per unit increase in bile salt output, followed by chenodeoxycholate and cholate. The two 7 beta-hydroxylated bile salts induced greater cation secretion than did their 7 alpha-epimers. Whereas biliary concentration of divalent cations differed depending on the structure and concentration of the infused bile salt, the concentration of monovalent cations was constant for any species and concentration of infused bile salt. Relationships between bile salt and divalent cation concentration indicate that 1 mumol of secreted biliary deoxycholate, the most hydrophobic bile salt, associates with the greatest amount of calcium (0.046 mumol) and magnesium (0.022 mumol), followed by chenodeoxycholate (0.020 and 0.010 mumol, respectively) and cholate (0.012 and 0.008 mumol, respectively). The capacity of ursodeoxycholate and ursocholate to associate with calcium and magnesium seems to be less than that of their 7 alpha-epimers. These data suggest that of the common bile salts, the more hydrophobic bile salts stimulate bile flow and cation secretion better than the more hydrophilic bile salts, whereas ursodeoxycholate and ursocholate are more effective than their more hydrophobic 7 alpha-epimers. Whereas different bile salts seem to influence the secretion of sodium and potassium mainly by virtue of their choleretic properties, the effect of bile salt structure on biliary secretion of calcium and magnesium suggests the presence of a secretory link that might be consistent with cation-bile salt binding.

Bile↗
PubMed1986

Terminal erythroid differentiation in the K-562 cell line by 1-beta-D-arabinofuranosylcytosine: accompaniment by c-myc messenger RNA decrease.

Two erythroid markers, acetylcholinesterase and hemoglobin, can be reversibly induced in the K-562 cell line after sodium butyrate treatment. In the present paper we show that 1-beta-D-arabinofuranosylcytosine (ara-C), induces the coordinate, irreversible expression of these two erythroid markers. This induction occurs at an ara-C concentration (0.05 mM) that results in K-562 cytostasis and is accompanied by deep morphological changes of cells. The differentiated phenotype is independent of the K-562 cell clone used [K-562, K-562 (S), K-562 (S)P] and is associated with the loss of cell renewal capacity. Continuous presence of the inducer is not necessary to achieve terminal differentiation. In contrast to what is seen for other inducers (sodium butyrate and hemin), one of the early effects of ara-C treatment is the marked decrease of c-myc mRNA expression after the first 4 hours of induction, whereas N-ras and histone 4 expression remain constant during the first 48 h. Our results suggest that ara-C treatment can irreversibly activate the erythroid differentiative program of K-562 cells.

Acetylcholinesterase↗
PubMed1985

Effect of acute administration of bile acids on fatty acid composition of biliary phosphatidylcholine in man.

Little is known on variations in fatty acid composition of biliary phosphatidylcholine (PC) during acute administration of particular bile acids (BAs) in man. Bile was collected hourly for 5 h in 6 T-tube patients (prereplacement period). Thereafter particular BAs were infused into the duodenum at a rate of 1 g/h for 5 h and bile collected hourly (replacement period). Each patient received two BAs at an interval of 3 days, following a cross-over design. Three patients received deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) and a second 3 patients cholic acid (CA) and chenodeoxycholic acid (CDCA). Bile acid pool contained mainly the two primary BAs in the prereplacement period and more than 80% administered BAs in the replacement period. Hydrophobic and detergent BAs (DCA and CDCA) increased the secretion rates and the percentage of biliary PC species with arachidonic acid and stearic acid; in contrast less detergent BAs (UDCA and CA) did not significantly alter fatty acid composition of biliary PC. Thus, very hydrophobic and detergent BAs would seem to promote the preferential secretion into the bile of lecithin species present in the liver cell plasma membranes, rich in arachidonic and stearic acid.

Adult↗
PubMed1981

High mobility group proteins 1 and 2 are present in simian virus 40 provirions, but not in virions.

Viral particles at the late stages of SV40 morphogenesis were examined for the presence of HMG proteins 1 and 2, by an immunochemical method involving the transfer of proteins from polyacrylamide gels to nitrocellulose membranes. It was found that these proteins are present in SV40 provirions, in which histone H1 is still associated with viral chromatin, but absent in mature SV40 virions.

Chromosomal Proteins, Non-Histone↗
PubMed1981

Effect of the selective expansion of cholic acid pool on bile lipid composition: possible mechanism of bile acid induced biliary cholesterol desaturation.

The effect of cholic acid pool expansion on biliary lipid composition was investigated in 21 subjects with cholesterol gallstones. All subjects were fed cholic acid (15 mg/kg/day) and ampicillin (2 g/day) in order to depress the intestinal degradation of cholic to deoxycholic acid. Five additional subjects were given ampicillin alone. The treatment lasted 2-3 wk. Parameters investigated included biliary and plasma lipid, biliary bile acid composition, and total and individual bile acid pool size. In 11 of 21 subjects (group I) cholic acid pool expanded two-threefold, whereas deoxycholic acid pool increased only slightly. In this group mean saturation index fell from 1.32 +/- 0.27 (mean +/- SD) to 0.93 +/- 0.25 (p less than 0.001), and plasma cholesterol increased from 185 +/- 45 mg/dl before to 213 +/- 37 after treatment (p less than 0.01). In the remaining 10 subjects (group II) the increase of the deoxycholic acid pool for exceeded that of cholic acid, and in these subjects the saturation index rose from a mean value of 1.07 +/- 0.27 to 1.42 +/- 0.22 after treatment (p less than 0.01). In this group plasma cholesterol tended to decrease (from 213 +/- 57 to 197 +/- 51 after treatment). In the 5 subjects treated with ampicillin alone deoxycholic acid pool was greatly reduced, and the saturation index fell from 1.25 +/- 0.25 to 0.95 +/- 0.35. The results suggest that cholic acid pool expansion reduces bile cholesterol saturation, whereas the increase of deoxycholic acid pool tends to supersaturate the bile. It is concluded that a determinant of bile cholesterol saturation might be the detergent power of the bile acid pool.

Adult↗
PubMed1980

Solid phase radioimmunoassay for chromosomal components.

This manuscript describes the use of a solid phase radioimmunoassay for serological analysis of chromosomal components. The applicability of this assay for various studies on nonhistone chromosomal proteins, histones, and chromatin subunits is illustrated. By this technique it is possible to detect and quantify nuclear antigens in the nanogram range. The assay has all the inherent sensitivity and precision of radioimmunoassays and, as such, introduces a new, convenient method for serological analyses of chromosomal components. The results presented reconfirm the serological similarity among the HMG (high mobility group) proteins derived from various sources. The amount of HMG proteins present in mononucleosomes purified from calf thymus is similar to that present in mononucleosomes purified from HeLa cells, suggesting that various tissues contain similar amounts of these proteins. Per nucleosome, dinucleosomes and trinucleosomes contain as much HMG-1 protein as mononucleosomes, suggesting that the protein is not exclusively associated with those regions of DNA which have been solubilized by micrococcal nuclease. Part of the antigenic determinants present in HMG-1 forming a complex in the nucleosomal conformation do not interact with antibodies.

Animals↗
PubMed1979

Serological analysis of species specificity in the high mobility group chromosomal proteins.

The non-histone chromosomal protein of the high mobility group (HMG-1) present in mouse liver was purified to homogeneity. Antibodies against this protein as well as pure HMG-1 derived from calf thymus and HMG-E purified from duck erythrocytes were elicited in rabbits. The interaction between the antibodies and the immunogens was measured by passive hemoagglutination and by quantitative microcomplement fixation. Quantitative microcomplement fixation assays revealed that the immunological distance between HMG-1 from calf thymus and HMG-1 from mouse liver and duck erythrocytes was 15. This corresponds to 3% sequence differences. It was estimated that amino acid substitution occurred at about seven positions in the polypeptide chain. Thus, HMG-1 proteins display remarkable evolutionary conservation in their primary sequence, similar to that displayed by histones H4 and H3, suggesting that their biological function is dependent on stringent structural requirements. HMG-E protein is significantly different from both HMG-1 and HMG-2 derived from calf thymus. As such, it is a protein unique to avian erythrocytes.

Amino Acid Sequence↗
PubMed1979

Life history of mouse sperm protein. Intratesticular stages.

A basic protein fraction, migrating as a single band in acetic acid-urea gel, distinct from histones, was isolated from mouse sperm collected from vasa deferentia and caudae epididymides and was used to immunize female rabbits. The presence of antibodies to the mouse sperm protein (MSP) in the rabbit antisera was demonstrated by a cytoimmunofluorescence procedure using the cells of origin of the antigenic protein, the mature mouse sperm. The specificity of the antisera was verified by fluid and gel precipitation tests and by crossed immunoelectrophoresis. The latter procedure demonstrated the presence of two antigen-antibody systems, consonant with earlier reports that the basic chromosomal protein of mouse sperm is heterogeneous. MSP antigen in situ was recognized by the specific antibodies of the rabbit antisera only after the smear of mature sperm was treated with either of two reducing agents: 2-mercaptoethanol or dithiothreitol. However, when the immunofluorescence procedure was applied to untreated smears of mouse testicular cells, spermatids of all stages from 1 to 14-15 were positive, while spermatocytes, stage 16 spermatids and spermatozoa were negative. After treatment of testes smears with reducing agent, only spermatocytes remained negative. Those observations indicate the following: (a) MSP is immunogenic in a heterologous species; (b) its antigenic sites are detectable in spermatozoa and spermatids of all stages, but not in primary spermatocytes; (c) those antigenic sites become masked at about stage 15 of spermiogenesis and may be unmasked by treatment with a reducing agent. The interpretation is made, therefore, that one or more components of MSP are assembled at the beginning of spermiogenesis and undergo an alteration in the final intratesticular stage of spermatid maturation. That alteration may be presumed to be the formation of disulfide linkages between the cysteine residues.

Animals↗