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Biomedical subjects

M Caserta

Publications and source records attributed to M Caserta.

At least 19 recordsLinked to original sources
PubMed2003

Pulse rate in childhood: reference limits.

BACKGROUND AND AIM: Systematic quantitative resting pulse rate measurements may represent an additional parameter for the study of cardiovascular risk factors in youth as well as in adulthood. The aim of this study was to evaluate resting pulse rate and its distribution curve in order to define reference limits in a sample of adolescents from Turin, Italy. METHODS AND RESULTS: The study population consisted of 2230 children aged 12-18 years, who were randomly enrolled from Turin Junior High Schools. All of the participants underwent pulse rate, blood pressure and height measurements. The 5th and 95th percentiles of the pulse rate in boys and girls are reported by age and height. The pulse rate was higher in the girls, but progressively decreased with age and somatic growth in both genders. CONCLUSIONS: The present study provides reference blood pressure values by age, gender and height in a sample of male and female adolescents.

Adolescent↗
PubMed2001

Celiac plexus block: injectate spread and pain relief in patients with regional anatomic distortions.

BACKGROUND: The success of the neurolytic celiac plexus block, despite different approaches and methods used, depends on adequate spread of the injectate in the celiac area. This retrospective study was conducted to evaluate the patterns of alcohol spread and pain relief in patients with cancer or therapy-related anatomic distortion of the celiac area. METHODS: From 177 cancer patients who underwent computed tomography (CT)-guided single-needle neurolytic celiac plexus block via an anterior approach, a radiologist, blind to the aim of the study, retrospectively selected 105 patients with abnormal anatomy of the celiac area as judged by CT images obtained before the block. To evaluate CT patterns of neurolytic (mixed with contrast) spread, the celiac area was divided on the frontal plane into four quadrants: upper right and left and lower right and left, as related to the celiac artery. Results were expressed as the number of quadrants into which contrast spread, ie., four, three, two, or one quadrants with contrast. The patterns of contrast spread according to the number of quadrants with anatomic distortion were analyzed. Patient assessment by visual analog scale was reviewed to evaluate the degree of pain relief. Pain relief 30 days after block was considered long-lasting. Pain relief at 30 days after block was analyzed according to the number of quadrants with contrast. RESULTS: Overall, four, three, two, and one quadrants with contrast were observed in 9 (8%), 21 (20%), 49 (47%), and 26 (25%) patients, respectively. An inverse correlation was observed between the number of quadrants with anatomic distortion and the number of quadrants with contrast (P < 0.001). Long-lasting pain relief was noticed in nine of nine patients (100%; 95% confidence interval, 66-100) with contrast in four-quadrants, and in 10 of 21 patients (48%; 95% confidence interval, 26-70) with contrast in 3 quadrants (P < 0.01). None of the 75 patients with contrast in two quadrants or one quadrant experienced long-lasting pain relief. CONCLUSIONS: These findings suggest that, using the single-needle anterior approach, the neurolytic spread in the celiac area is highly hampered by the regional anatomic alterations. It also appears that only a complete (four quadrants) neurolytic spread in the celiac area can guarantee long-lasting analgesia, and that this picture may be obtained in a very limited fraction of patients with regional anatomic alterations.

Adult↗
PubMed2000

Two distinct nucleosome alterations characterize chromatin remodeling at the Saccharomyces cerevisiae ADH2 promoter.

Glucose depletion derepresses the Saccharomyces cerevisiae ADH2 gene; this metabolic change is accompanied by chromatin structural modifications in the promoter region. We show that the ADR6/SWI1 gene is not necessary for derepression of the wild type chromosomal ADH2, whereas the transcription factor Adr1p, which regulates several S. cerevisiae functions, plays a major role in driving nucleosome reconfiguration and ADH2 expression. When we tested the effect of individual domains of the regulatory protein Adr1p on the chromatin structure of ADH2, a remodeling consisting of at least two steps was observed. Adr1p derivatives were analyzed in derepressing conditions, showing that the Adr1p DNA binding domain alone causes an alteration in chromatin organization in the absence of transcription. This alteration differs from the remodeling observed in the presence of the Adr1p activation domain when the promoter is transcriptionally active.

Alcohol Dehydrogenase↗
PubMed1997

Factors affecting Saccharomyces cerevisiae ADH2 chromatin remodeling and transcription.

The chromatin structure of the Saccharomyces cerevisiae ADH2 gene is modified during the switch from repressing (high glucose) to derepressing (low glucose) conditions of growth. Loss of protection toward micrococcal nuclease cleavage for the nucleosomes covering the TATA box and the RNA initiation sites (-1 and +1, respectively) is the major modification taking place and is strictly dependent on the presence of the transcriptional activator ADR1. To identify separate functions involved in the transition from a repressed to a transcribing promoter, we have analyzed the ADH2 chromatin organization in various genetic backgrounds. Deletion of the CCR4 gene coding for a general transcription factor impaired ADH2 expression without affecting chromatin remodeling. Growing yeast at 37 degrees C also resulted in chromatin remodeling at the ADH2 locus even under glucose repressing conditions. However, although this temperature-induced remodeling was dependent on the ADR1 protein, no ADH2 mRNA was observed. In addition, inactivating RNA polymerase II (and therefore, elongation) was found to have no effect on the ability to reconfigure nucleosomes. Taken together, these data indicate that chromatin remodeling by itself is insufficient to induce transcription at the ADH2 promoter.

Alcohol Dehydrogenase↗
PubMed1997

Chromatin structure of the Saccharomyces cerevisiae DNA topoisomerase I promoter in different growth phases.

We have determined the chromatin organization of the Saccharomyces cerevisiae DNA topoisomerase I promoter. Three nucleosomal core particles have been mapped at nucleotide level over the promoter region, encompassing the presumptive TATA sequence and the two RNA initiation sites; the most upstream nucleosome particle forms on to a 29 bp-long poly(dA-dT) element. This simple organization remains constant throughout both the logarithmic and the linear phase of growth, with the exception of an increased accessibility to micrococcal nuclease of the nucleosome covering the TATA box and the RNA initiation sites during the diauxic shift (the switching from the fermentative to the respiratory metabolism) in parallel with an increase of the DNA topoisomerase I mRNA. In addition, a strong disorganization of the bulk chromatin structure in the late stationary phase is also reported.

Chromatin↗
PubMed1996

The active role of DNA as a chromatin organizer.

Histone octamers (hos) and DNA topoisomerase I contribute, along with other proteins, to the higher order structure of chromatin. Here we report on the similar topological requirements of these two protein model systems for their interaction with DNA. Both histone octamers and topoisomerase I positively and consistently respond to DNA supercoiling and curvature, and to the spatial accessibility of the preferential interaction sites. These findings (1) point to the relevance of the topology-related DNA conformation in protein interactions and define the particular role of the helically phased rotational information; and (2) help to solve the apparent paradoxical behaviour of ubiquitous and abundant proteins that interact with defined DNA sites in spite of the lack of clear sequence consensuses. Considering firstly, that the interactions with DNA of both DNA topoisomerase I and histone octamers are topology-sensitive and that upon their interaction the DNA conformation is modified; and secondly, that similar behaviours have also been reported for DNA topoisomerase II and histone H1, a topology-based functional correlation among all these determinants of the higher order structure of chromatin is here suggested.

Animals↗
PubMed1996

Chromatin remodeling during Saccharomyces cerevisiae ADH2 gene activation.

We have analyzed at both low and high resolution the distribution of nucleosomes over the Saccharomyces cerevisiae ADH2 promoter region in its chromosomal location, both under repressing (high-glucose) conditions and during derepression. Enzymatic treatments (micrococcal nuclease and restriction endonucleases) were used to probe the in vivo chromatin structure during ADH2 gene activation. Under glucose-repressed conditions, the ADH2 promoter was bound by a precise array of nucleosomes, the principal ones positioned at the RNA initiation sites (nucleosome +1), at the TATA box (nucleosome -1), and upstream of the ADR1-binding site (UAS1) (nucleosome -2). The UAS1 sequence and the adjacent UAS2 sequence constituted a nucleosome-free region. Nucleosomes -1 and +1 were destabilized soon after depletion of glucose and had become so before the appearance of ADH2 mRNA. When the transcription rate was high, nucleosomes -2 and +2 also underwent rearrangement. When spheroplasts were prepared from cells grown in minimal medium, detection of this chromatin remodeling required the addition of a small amount of glucose. Cells lacking the ADR1 protein did not display any of these chromatin modifications upon glucose depletion. Since the UAS1 sequence to which Adr1p binds is located immediately upstream of nucleosome -1, Adr1p is presumably required for destabilization of this nucleosome and for aiding the TATA-box accessibility to the transcription machinery.

Alcohol Dehydrogenase↗
PubMed1994

Conformational information in DNA: its role in the interaction with DNA topoisomerase I and nucleosomes.

Information in DNA is not limited to sequence information. Both local and global conformational parameters are pivotal to the interaction with a number of relevant proteins. The function of the major components of the transcription machinery (RNA polymerase II, DNA topoisomerase I, nucleosomes, the TATA-binding factor) is dependent on the topological status of the substrate DNA molecule. The topological requirements and the conformational consensus that dictate the rules for localization of nucleosomes and define the active sites for DNA topoisomerase I have been established; the reaction of DNA topoisomerase I is regulated by a topological feedback mechanism. The integrating function of the free energy of supercoiling in the transcription process and the regulatory role of DNA topoisomerase I are discussed.

Animals↗
PubMed1994

Understanding depression in bereaved older adults.

Depression is a common outcome of spousal bereavement. Concurrent life events may contribute to the intensity of depression following spousal bereavement in older adults and, if not identified, may interfere with therapeutic plans for the management of depression. Taped interviews, conducted six times over two years, were analyzed for ten subjects, five whose depression scores were low, and five whose scores were high. In addition, a detailed case comparison analysis of two subjects was done. Four recurring types of life events, reported by the bereaved spouses, were illness (of self or others), deaths of family or friends, residential relocation, and changes in interpersonal relationships. Significantly depressed spouses were more likely to report these events. Implications for nursing practice and for integrating qualitative and quantitative research methods are addressed.

Age Factors↗
PubMed1993

DNA tridimensional context affects the reactivity of eukaryotic DNA topoisomerase I.

Cleavage sites of eukaryotic DNA topoisomerase I on curved linear DNAs are clustered, map on the same side of the curve (the external one) and their distribution has the same period as the helical repeat, as observed on curved DNA tracts of Crithidia fasciculata, of Saccharomyces cerevisiae ARS1, of pT7CAT and on synthetic DNAs. The effects of the tridimensional context on both the cleavage and the topoisomerization reactions of DNA topoisomerase I were determined using serial DNA constructs made with inserts in which synthetic curves lie in a plane and in which the orientation of the planes of curvature is shifted by 72 degrees, 144 degrees, 216 degrees, 288 degrees and 360 degrees. The insertion of a curve markedly changes the reaction properties of the surrounding sequences.

Animals↗
PubMed1993

DNA topoisomerase I controls the kinetics of promoter activation and DNA topology in Saccharomyces cerevisiae.

Inactivation of the nonessential TOP1 gene, which codes for Saccharomyces cerevisiae DNA topoisomerase I, affects the rate of transcription starting at the ADH2 promoter. For both the chromosomal gene and the plasmid-borne promoter, mRNA accumulation is kinetically favored in the mutant relative to a wild-type isogenic strain. The addition of ethanol causes in wild-type yeast strains a substantial increase in linking number both on the ADH2-containing plasmid and on the resident 2 microns DNA. Evidence has been obtained that such an in vivo increase in linking number depends on (i) the activity of DNA topoisomerase I and of no other enzyme and (ii) ethanol addition, not on the release from glucose repression. A direct cause-effect relationship between the change in supercoiling and alteration of transcription cannot be defined. However, the hypothesis that a metabolism-induced modification of DNA topology in a eukaryotic cell plays a role in regulating gene expression is discussed.

Alcohol Dehydrogenase↗
PubMed1991

The conformation of constitutive DNA interaction sites for eukaryotic DNA topoisomerase I on intrinsically curved DNAs.

The analysis of the sites which are cleaved constitutively and preferentially by eukaryotic DNA topoisomerase I on two intrinsically curved DNAs reveals the conformational features that provoke the cleavage reaction on the curve-inducing sequence elements in the absence of supercoiling. This analysis is based on the observation (Caserta et al. (1989) Nucleic Acids Res. 17, 8521-8532 and (1990) Biochemistry 29, 8152-8157) that the reaction of eukaryotic DNA topoisomerase I occurs on two types of DNA sites: sites S (Supercoiled induced) and sites C (Constitutive, whose presence is topology-independent). We report that sites C are abundant on the intrinsically curved DNAs analyzed. The DNAs studied were two intrinsically curved segments of different origin: the Crithidia fasciculata kinetoplast DNA and the bent-containing domain B of the Saccharomyces cerevisiae ARS1. On these DNA segments DNA topoisomerase I cleaves at the junctions between the poly(A) tracts and mixed-sequence DNA. Analysis of the conformation of the double helix around the cleavage sites has revealed that the reaction occurs in correspondence of a defined DNA conformational motif. This motif is described by the set of Eulerian angular values that define the axial path of DNA (helical twist, deflection angle, direction) and of the orthogonal components of wedge (roll and tilt).

Animals↗
PubMed1991

Expression of lymphocyte homing receptor gene is lost in multi-drug-resistant variants of human T-lymphoblastoid CCRF-CEM cells.

The 2.2-kb human cDNA clone PBL32, encoding for the lymphocyte homing receptor (LHR) was used to study the expression of this determinant in multi-drug-resistant (MDR) variants of human T-lymphoblastoid CCRF-CEM (CEM) cells. LHR is significantly associated with the drug-sensitive phenotype, its expression being progressively and quantitatively reduced in MDR variants of CEM cells according to the extent of drug resistance.

Drug Resistance↗
PubMed1990

Regulation of the function of eukaryotic DNA topoisomerase I: analysis of the binding step and of the catalytic constants of topoisomerization as a function of DNA topology.

It was previously observed that two steps of the reaction of eukaryotic DNA topoisomerase I (topoisomerization and cleavage) depend upon the conformation of the DNA substrate: in both instances the supercoiled form is a more efficient substrate than the relaxed one. This paper reports the analysis of two other steps of the reaction: the binding of DNA topoisomerase I to DNA and the catalytic constants (Kcs) of topoisomerization as a function of the topology of the substrate. Binding. Competition assays show that supercoiled DNA binds the enzyme with even slower kinetics than the relaxed form. Therefore, the preferential topoisomerization of supercoiled DNA is not due to the binding step. Additional evidence that the rate-limiting step of the topoisomerization reaction is not the binding of the enzyme to DNA is provided by the fact that the kinetics of relaxation is first order. Catalysis. The Kcs of the topoisomerization reaction have been calculated and it was shown that they do not vary as a function of the topology of the substrate or of its size. Taken together, the data on binding, cleavage, topoisomerization, and Kcs suggest that the preferential topoisomerization of torsionally strained DNA is due to the higher availability, on this topological form, of DNA sites that allow the onset of the reaction.

Animals↗
PubMed1989

In vitro preferential topoisomerization of bent DNA.

The steps of the topoisomerization reaction by calf thymus DNA topoisomerase I on a DNA domain containing an intrinsically bent DNA sequence have been analyzed. High preferentiality of binding, cleavage and topoisomerization on the bent segment relative to the rest of the DNA domain was observed. These studies show the importance of the local DNA conformation in the reaction of eukaryotic DNA topoisomerase I and the interest of the use of this enzyme as a tool for the analysis of DNA conformation and DNA dynamics.

Animals↗
PubMed1989

Regulation of the function of eukaryotic DNA topoisomerase I: topological conditions for inactivity.

The effects of supercoiling on the cleavage reaction by eukaryotic DNA topoisomerases I (wheat germ, chicken erythrocyte, and calf thymus) have been analyzed on DNA fragments (0.96 and 2.3 kilobases) encompassing an immunoglobulin kappa light-chain promoter. In one topological condition of the substrate, the absolutely relaxed state, cleavage was found to be impeded. This finding defines the topology-dependent step of the eukaryotic DNA topoisomerase I reaction and shows that for the cleavage reaction topology is more critical than sequence effects. These findings suggest a simple model for the regulation of the DNA topoisomerase I reaction based on topological factors, which may explain the regulatory function of the enzyme in in vivo eukaryotic transcription.

Animals↗