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Biomedical subjects

S Ferrari

Publications and source records attributed to S Ferrari.

At least 379 records · Page 21Linked to original sources
PubMed1981

Sequence complexity and diversity of polyadenylated RNA molecules of human normal resting, PHA-stimulated and leukemic lymphocytes.

The abundance and complexity of total poly(A)+RNA of human normal unstimulated lymphocytes, PHA-stimulated and leukemic lymphocytes were examined using the cDNA-poly(A)+ RNA hybridization technique. It was found that in both PHA-stimulated and leukemic lymphocytes the complexity of total poly(A)+RNA is strongly reduced in respect to normal unstimulated lymphocytes. The differences is due to a small portion, by weight, of high complexity sequences, suggesting the involvement or nuclear, not necessarily transcriptional, events. Moreover the heterologous hybridizations show that: 1) in PHA-stimulated lymphocytes there is a set of highly abundant sequences which are represented in normal and leukemic lymphocytes at a very reduced rate; 2) the sequences abundant in normal unstimulated lymphocytes are less represented in leukemic lymphocytes; the converse also is true, but at a lower extent. On the basis of available data, it is suggested that the observed changes in the abundance pattern of PHA-stimulated lymphocytes may be related mainly to a difference in the half-life of the mRNAs, while those of leukemic lymphocytes require some transcriptional or post-transcriptional nuclear event.

Base Sequence↗
PubMed1980

Specific RNA-cleaving activities from HeLa cells.

Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate activities--cleavage of HeLa cell heterogeneous nuclear RNA, the HeLa cell 45S rRNA precursor, RNA . DNA hybrids (RNase H), and the Escherichia coli tRNATyr precursor (RNase P)--were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA-processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage T7, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A)-containing RNA.

Cell Nucleus↗
PubMed1980

[Role of M-mode and 2-dimensional (sector-scan) echocardiography in studying postinfarct ventricular kinetic changes].

20 patients with previous myocardial infarction clinically suspected to have large impairment of ventricular wall kinesis were studied to evaluate the contribution of M-mode and two-dimensional echocardiography compared with the cineangiographic study in detecting left ventricular asynergy. Two-dimensional cross-sectional echocardiography yielded a satisfactory overlapping of results with ventriculography as far as left ventricular internal dimension and apical and posterior wall kinesis were concerned. The two-dimensional study proved to be an useful technique to observe the interventricular septum, in all its extension and the lateral wall as well. The M-mode technique, on the other hand, provided a reliable method, by means of the mitral valve echo, to determine the presence of elevated left-ventricular end-diastolic pressure; this was indicated by the occurrence of a B point, on the AC slope. A late opening of the mitral valve compared with the onset of left ventricular posterior wall relaxation phase, and other anomalies observed on the CD slope (SAM or pseudo-SAM), indicated pathological left ventricular kinesis. The failure of the left ventricular posterior wall to reach the septum moving the transducer from the aorta to the cardiac apex was considered indicative of apical dilatation, even if limited by a great number of false negatives. M-mode echocardiography provided also a quantitative evaluation of septal and postero-basal wall movement (particularly important from a prognostic point of view) and left ventricular end-diastolic dimension which, if corrected by body surface, resulted similar to those obtained by the two-dimensional technique. M-mode and Two-dimensional cross sectional echocardiography appeared to be complementary techniques which allow an adequate evaluation and diagnosis of left ventricular asynergy. They seem to be particularly useful to follow prospectively patients affected by myocardial infarction.

Adult↗
PubMed1980

[M-mode and two-dimensional echocardiography in subjects with suspected infective endocarditis. Report of 4 cases (author's transl)].

4 hospitalized patients with valvular disease or prosthetic valves clinically suspected for infective endocarditis, were studied. The diagnostic contributions of echocardiography are reported. In fact this technique allows evidencing valvular vegetations with the possibility to clearly define their locations and dimensions, providing important data on the function of the affected structures. In particular the value of renal time cross sectional echocardiography is stressed. In fact this technique provided more detailed and specific images when compared with the M-mode tracings. All the echocardiographic results were compared with the surgical and/or autoptic data. In conclusion the importance of the echocardiographic approach in the study of valvular diseases is referred, stressing the utility of real time cross-sectional technique.

Adult↗
PubMed1979

Kinetics of hybridization to human DNA of heterogeneous nuclear RNA isolated from normal human lymphoblasts and acute leukemia blast cells.

Heterogeneous nuclear RNA was extracted from normal PHA-stimulated human lymphocytes and acute myeloid leukemia blast cells. Experiments were performed to determine the hybridization kinetics of these RNA's to human DNA. The best least squares solutions indicate in the hybridization reaction of both normal and leukemic RNA two main components. For leukemic cell RNA the rate constants of both components were significantly different from that of normal cell RNA. In particular, the difference between the rate constants of the second lower component suggests that the slowly hybridizing sequences in leukemic cell RNA have a degree of repetition higher than of the corresponding sequences of normal cell RNA.

Base Sequence↗
PubMed1979

Reassociation kinetics of the DNA of human acute leukemia cells.

Human DNA isolated from normal phytohaemagglutinin-stimulated human lymphocytes and from acute leukemia blast cells have been studied by renaturation techniques using hydroxyapatite binding and DNA hyperchromism. In the leukemic genome, the unique sequences account for 62% of the genome of leukemic DNA. Repetitive sequences may be subdivided into at least three fractions: (a) foldback sequences, which represent 5% of the genome; (b) sequences with high repetition frequency (3. 10(4) times on the average), which represent 12% of the genome; (c) sequences with low repetition frequency (10 times on the average), which represent 16% of the genome. The average length of the repetitive sequences is evaluated to be between 200 and 500 nucleotides. There are at least two patterns of interspersion of repetitive sequences with unique sequences of different length: short (about 2000 nucleotides on average) and long (not defined). The results of our experiments on DNA from normal phytohaemagglutinin-stimulated human lymphocytes are in close agreement with those reported by other authors studying different types of human cells. The human leukemic DNA, as far as the parameters that have been studied, does not significantly differ from normal human DNA.

Acute Disease↗
PubMed1977

[Effects of clonidine on various blood-coagulation parameters in hypertension].

The effect of oral clonidine on prothrombin time, partial thromboplastin time, blood fibrinogen, fibrinolytic activity and platelet count was investigated in 25 hypertensive and 7 normal subjects. High plasma fibrinogen levels were present in 80% of the hypertensive patients and prolonged lysis time in 28%; the means values were 487 +/- 135 mg % and 223 +/- 62 min., respectively. The other coagulation tests were normal. 0,300-0,450 mg/day clonidine per os for 15 days both decreased fibginogen levels (mean 406 +/- 149; p less than 0.05) and shortened lysis time (mean 153 +/- 78 min; p less than 0.005). No changes were noted in the normal subjects. The pathophysiological mechanism of these findings is discussed and their possible implications for the treatment of hypertension are emphasised.

Blood Coagulation↗
PubMed1977

In vitrocleavage of 45S pre-ribosomal RNA and of giant heterogeneous RNA extracted from human leukemic cells.

45S ribosomal precursor RNA and large heterogeneous RNA molecules (greater than 45S) extracted from human leukemic cells were incubated in vitro with purified RNase III, which specifically attacks double-helical RNA regions. About 50% of the ribosomal precursor was cleaved into two major fragments sedimenting at 28S and 32S respectively. A limited number of cleavages was also introduced in about 40% of heterogeneous RNA molecules sedimenting faster than 45S, causing a partial 'shift' to a polydisperse distribution in the 10S-45S range.

Cells, Cultured↗
PubMed1977

Immunological assay of double-helical segments in RNA fractions of different molecular size extracted from acute myeloid leukemia blast cells.

Whole-cell RNA, extracted from acute myeloid leukemia blast cells, was fractionated by sedimentation through sucrose gradients. The proportion of double-helical segments present in each fraction was then determined by a quantitative microcomplement fixation assay that specifically measures double-helical RNA. Sizable amounts of double-helical segments were detected in all fractions of cellular RNA corresponding to S values higher than approximately 20. In all cell populations examined the highest proportion of double-helical segments was found in RNA fractions sedimenting faster then the 45 S ribosomal precursors RNA, i.e., in fractions including only heterogeneous nuclear RNA.

Antibody Specificity↗
PubMed1976

Accumulation of giant heterogeneous RNA molecules in acute myeloid leukemia blast cells.

Time course and "chase" experiments showed that, after incubation of acute myeloid leukemia blast cells with a labeled RNA precursor, a large proportion of radioactivity remained associated with RNA molecules larger than 45 S even after several hr. Double-labeling experiments with [5-3H]uridine and [methyl-14C]methionine indicated that unmethylated giant heterogeneous RNA larger than 45 S is processed much more slowly than the 45 S ribosomal precursor, so that relatively large amounts of fairly stable RNA of the former class accumulate in the cell. The measurement of labeled giant heterogeneous RNA molecules bound to polyuridylate-fiberglass filters showed that molecules carrying polyadenylate segments seemingly turn over faster than those lacking polyadenylate.

Dactinomycin↗