Evolution of satellite DNA sequences in two tribes of Bovidae: A cautionary tale.

Two clones, Bt1 from Bos taurus and Om1 from Ovis orientalis musimon, were used as probes for hybridization on genomic DNA and on metaphase chromosomes in members of Bovini and Caprini tribes. Bt1 and Om1 are sequences respectively belonging to the 1.715 and 1.

A historical overview of bromo-substituted DNA and sister chromatid differentiation.

The thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) has been widely used to make sister chromatid differentiation (SCD) evident in metaphase chromosomes of cells grown for two cycles in BrdU and, thus, containing varying amounts of the thymidine analogue. A direct consequence was the possibility of making sister chromatid exchange (SCE) evident without using autoradiographic procedures. The latter phenomenon was first discovered in 1953, and its frequency is considered a reliable marker of pathological cell situations, as well as an indicator of mutagenic compounds.

[Management strategies and choice of antithrombotic treatment in patients admitted with acute coronary syndrome--executive summary for clinical practice. Consensus Document of the Regional Chapters of the Italian National Association of Hospital Cardiologists (ANMCO) and of the Italian Society of Emergency Medicine (SIMEU)].

This document has been developed by the Lazio regional chapters of two scientific associations, the Italian National Association of Hospital Cardiologists (ANMCO) and the Italian Society of Emergency Medicine (SIMEU), whose members are actively involved in the everyday management of Acute Coronary Syndromes (ACS). The document is aimed at providing a specific, practical, evidence-based guideline for the effective management of antithrombotic treatment (antiplatelet and anticoagulant) in the complex and ever changing scenario of ACS. The document employs a synthetic approach which considers two main issues: the actual operative context of treatment delivery and the general management strategy.

Identification of two new repetitive elements and chromosomal mapping of repetitive DNA sequences in the fish Gymnothorax unicolor (Anguilliformes: Muraenidae).

Muraenidae is a species-rich family, with relationships among genera and species and taxonomy that have not been completely clarified. Few cytogenetic studies have been conducted on this family, and all of them showed the same diploid chromosome number (2n=42) but with conspicuous karyotypic variation among species. The Mediterranean moray eel Gymnothorax unicolor was previously cytogenetically studied using classical techniques that allowed the characterization of its karyotype structure and the constitutive heterochromatin and argyrophilic nucleolar organizer regions (Ag-NORs) distribution pattern.

Chromosomal localisation and genetic variation of the SLC11A1 gene in goats (Capra hircus).

The solute carrier family 11 member A1 (SLC11A1) gene is associated with resistance to infectious diseases. Chromosomal localisation, genomic regions corresponding to functional domains and the genetic variability of microsatellites in the 3' untranslated region (3'-UTR) of this gene were investigated in 427 goats (Capra hircus) of six breeds. Using dual colour fluorescence in situ hybridisation, SLC11A1 was localised to goat chromosome 2.

[Secondary cardiovascular prevention after acute coronary syndrome in clinical practice].

Secondary prevention after acute coronary syndromes should be aimed at reducing the risk of further adverse cardiovascular events, thereby improving quality of life, and lengthening survival. Despite compelling evidence from large randomized controlled trials, secondary prevention is not fully implemented in most cases after hospitalization for acute coronary syndrome. The Lazio Region (Italy) has about 5.

An unusual complication following pericardiocentesis: reversible left ventricular dysfunction.

We report a case of a 78-year-old woman admitted to hospital due to cardiac tamponade 3 months after surgical mitral valve repair. The patient developed an early left ventricular dysfunction after removal of the pericardial effusion, with complete recovery within 10 days. Transient ventricular dysfunction after pericardiocentesis is a very rare complication, we present a review of the different mechanisms suggested in the literature to explain the pathophysiology of this rare phenomenon.

Shared Y chromosome repetitive DNA sequences in stallion and donkey as visualized using whole-genomic comparative hybridization.

The genome of stallion (Spanish breed) and donkey (Spanish endemic Zamorano-Leonés) were compared using whole comparative genomic in situ hybridization (W-CGH) technique, with special reference to the variability observed in the Y chromosome. Results show that these diverging genomes still share some highly repetitive DNA families localized in pericentromeric regions and, in the particular case of the Y chromosome, a sub-family of highly repeated DNA sequences, greatly expanded in the donkey genome, accounts for a large part of the chromatin in the stallion Y chromosome.

A highly conserved pericentromeric domain in human and gorilla chromosomes.

Significant similarity between human and gorilla genomes has been found in all chromosome arms, but not in centromeres, using whole-comparative genomic hybridization (W-CGH). In human chromosomes, centromeric regions, generally containing highly repetitive DNAs, are characterized by the presence of specific human DNA sequences and an absence of homology with gorilla DNA sequences. The only exception is the pericentromeric area of human chromosome 9, which, in addition to a large block of human DNA, also contains a region of homology with gorilla DNA sequences; the localization of these sequences coincides with that of human satellite III.

Whole-comparative genomic hybridization in domestic sheep (Ovis aries) breeds.

Whole-comparative genomic hybridization (W-CGH) allows identification of chromosomal polymorphisms related to highly repetitive DNA sequences localized in constitutive heterochromatin. Such polymorphisms are detected establishing competition between genomic DNAs in an in situ hybridization environment without subtraction of highly repetitive DNA sequences, when comparing two species from closely related taxa (same species, sub-species, or breeds) or somewhat related taxa. This experimental approach was applied to investigating differences in highly repetitive sequences of three sheep breeds (Castellana, Ojalada, and Assaf).

Some remarks on the use of TaqI to detect highly repetitive DNA sequences in human chromosomes.

In the attempt to conclude investigation of the action of restriction endonucleases on eukaryote chromosomes, we carried out a series of experiments digesting in situ human metaphase chromosomes with AluI/TaqI followed by Giemsa staining. We focused on the centromeric regions of chromosomes1, 2 and 16 and noted that those areas appeared as intensely stained blocks after AluI digestion, but were dramatically reduced in size or completely destroyed after subsequent TaqI treatment. These results permitted us to draw some conclusions on the highly repetitive DNA composition of these regions, in terms of alphoid and classical satellite DNAs.

The organization of classical satellite DNAs in human chromosomes: an approach using AluI and TaqI restriction endonucleases.

Human classical satellite DNAs were used as probes to investigate the molecular mechanism(s) of AluI/TaqI attack in situ on specific centromeric areas. The biochemical results obtained show that the majority of such highly repetitive DNAs are not solubilized from chromosomes, in spite of a cleavage pattern identical to that shown in naked genomic DNA digested with the same enzymes. Moreover, when digestion in situ with restriction enzymes precedes in situ hybridization, it is possible to observe an increased signal in the centromeres of some chromosomes as compared to that shown in standard undigested chromosomes and, on the other hand, hybridization labelling in centromeres which are difficult to detect by in situ hybridization using standard undigested chromosomes.

The impact of StuI digestion in situ on FISH to human chromosomes with satellite DNA probes.

Human metaphase chromosomes were digested with StuI and subsequently hybridized in situ using chromosome 9 alphoid DNA and classical satellite III DNA as probes. The data obtained suggest that it is not possible to establish a general rule regarding the cytological effects induced by restriction enzymes in particular chromosome regions and that a number of factors, such as DNA sequences, DNA-protein interaction and enzyme structure, play a role in determining such effects.

The efficiency of in-situ hybridization on human chromosomes with alphoid DNAs is enhanced by previous digestion with AluI and TaqI.

Centromeric alphoid DNAs of human chromosomes 6, 9, 16 and Y were employed to obtain information on the molecular mechanism(s) determining cytological effects produced by digestion in situ with AluI and TaqI restriction enzymes, possibly related to the structure of the above-cited areas. The following cytological and biochemical experiments were carried out using the above-mentioned alphoid sequences as probes: (1) standard in-situ hybridization and in-situ hybridization after chromosome cleavage with AluI/TaqI, and (2) filter hybridization on the DNA fractions obtained from the material solubilized and that retained on the slides after digestion in situ with AluI/TaqI. Biochemical data show that cleavage of alphoid DNAs is not prevented by the peculiar organization of centromeric heterochromatin, but such cleavage is not necessarily followed by complete DNA solubilization.

The effects of enzyme inactivation and incubation buffer on digestion in situ with restriction endonucleases.

Previous studies have shown that components of the incubation reaction other than the restriction endonucleases in an in situ restriction enzyme digest of chromosomes may induce G-like banding patterns. To determine whether factors other than DNA base composition play a role in determining restriction enzyme induced bands, we investigated the effect of reaction buffers alone or in the presence of heat inactivated enzymes. Our results show that enzymes such as AluI, RsaI and MspI become inactivated during 3-24 hr incubations at 37 C and that reaction buffers alone failed to produce G-like bands when inactive endonucleases were included.

[Improvement of postinfarct left myocardial contractile function after administration of diltiazem].

Background: The impairment of intracellular calcium homeostasis is an important biochemical alteration in stunned and hibernating myocardium. These different forms of viable myocardium frequently occur after myocardial infarction and their recognition may modify the therapeutic program and prognosis. Experimental studies and experiences on male subjects have demonstrated that calcium-channel blockers exert a protective action on myocardial reperfusion injury and reduce infarct size.

On the presence of DNA polymerase alpha in human lymphocyte nuclei and chromosomes.

Experiments were carried out to correlate the cytological localization of DNA polymerase alpha with the presence of its specific mRNA in human lymphocytes studied at different times after phytohaemagglutinin stimulation. Our data indicated that in resting cells it is not possible to detect DNA polymerase alpha protein or mRNA by Northern hybridization. By contrast, in stimulated cells the detection of mRNA specific for DNA polymerase alpha synthesis is possible after 16 h phytohaemagglutin stimulation, whereas immunolocalization is possible after only 4 h stimulation.

The molecular characterization of the genome of Muraena helena L. I. Isolation and hybridization of two MboI-restricted DNA fractions.

To investigate the genome of the anguilliform fish Muraena helena at the molecular level we characterized total DNA by agarose gel electrophoresis after cleavage with AluI, HaeIII, MboI, and DdeI restriction endonucleases. Subsequently, we isolated the DNA from two specific electrophoretic fractions to be used as probes for Southern and in situ hybridization experiments. One such fraction showed an electrophoretic pattern typical of highly repetitive DNA localized in the centromeres of many chromosomes.

Characterization of Dasypyrum villosum (L.) candargy chromosomal chromatin by means of in situ restriction endonucleases, fluorochromes, silver staining and C-banding.

The distribution of C-banded heterochromatin was determined in an inbred line of Dasypyrum villosum. Practically no difference in chromosome morphology or band distribution could be observed within the chromosomes of the same pair. Heterochromatin bands, revealed by Giemsa banding, were characterized by means of their differential reaction to fluorochromes, silver staining and in situ digestion with different restriction endonucleases.

Sister chromatid differentiation in 5-bromo-2'-deoxyuridine-substituted chromosomes: a study with DNA-specific ligands and monoclonal antibody to histone H2B.

Human and Chinese hamster chromosomes were obtained from cells grown in the presence of 5-bromodeoxyuridine (BrdU) for (a) one replicative round, (b) two replicative rounds, (c) one replicative round followed by another round in thymidine and (d) the last period of synthetic phase. Untreated chromosomes and chromosomes treated with UV radiation after previous staining with 33258 Hoechst as photosensitizer were studied in order to investigate the mechanism(s) responsible for BrdU-induced sister chromatid differentiation (SCD). Metaphases were prepared by (1) standard methanol-acetic acid fixative for subsequent investigation with Giemsa or DNA-specific dyes such as ethidium bromide, acridine orange and monoclonal antibodies to double- or single-stranded DNA; (2) the procedure for observation under phase-contrast or electron microscopy; and (3) the cytospin method for subsequent immunoreaction with a monoclonal antibody to histone H2B.

Selective digestion of mouse chromosomes with restriction endonucleases. Oligonucleotide priming of single-stranded DNA produced with exonuclease III.

L-929 mouse chromosomes prepared for electron microscopy have been treated with MspI, EcoRI, and HaeIII restriction endonucleases (REs). RE-induced nicks were amplified with exonuclease III to obtain single-stranded DNA (ss-DNA) motifs. The ss-DNA produced was enough to permit hybridization of a series of random oligonucleotides.