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Biomedical subjects

J Paul

Publications and source records attributed to J Paul.

At least 271 records · Page 15Linked to original sources
PubMed1977

Comparison of the base-sequence complexities of polysomal and nuclear RNAs in growing Friend erythroleukemia cells.

The base-sequence complexities of polysomal poly(A)+ RNA, nuclear poly(A)+ RNA, and total nuclear RNA from Friend erythroleukemia cells in logarithmic phase of growth were determined by measuring the proportion of labeled unique mouse DNA sequences which formed hybrids when incubated with a vast excess of each RNA. It was estimated that the RNAs had been transcribed from 1.8, 7.6, and 8.3%, respectively, of the haploid mouse genome. Although these estimates for polysomal and nuclear poly(A)+ RNAs were 2.5 times greater than those previously determined by analysis of the kinetics of the hybridization reactions between the RNAs and the cDNAs transcribed from them, they confirmed that the base-sequence complexity of nuclear poly(A)+ RNA in these cells is at least four times greater than that of polysomal poly(A)+ RNA.

Base Sequence↗
PubMed1977

[Coagulation deficits and hemorrhagic consequences after cardiac surgery under ECC].

I--A statistical study of the results of tests of hemostasis was carried out in patients who had undergone major cardiac surgery with extra-corporeal circulation. There were two series of patients (1.504 and 547 operated) suffering mainly from congenital cardiopathies, valvulopathies or coronaritis. Bearing in mind the hematocrit and the total protein level, the following was studied before and after ECC and 24 hours after the intervation: the blood platelet level, fibrinogen, prothrombin and its cofactors, antithemophilic factors A and B, FDP amd fibrinolytic activity. The fall in platelet stickiness is specifically pointed out, and also the fall in the level of fibrin stablizing factor (factor XIII) which is met with after ECC, and which can explain the persistence of certain hemorrhagies. Furthermore, the fall in antithrombin III level then its rise can contribute to the "heparine rebound" occurring in certain cases after neutralization of heparinemia with protamine. II--The deficits in the quantitatively and qualitatively variable hemostatic factors do not necessarily lead to hemorrhage. Hemorrhage, due to biological causes, are met with in 5 to 6 p. 100 of the cases. Most of the time they are provoked by a residual hemorrhage or a "heparine rebound", deficits in coagulation factors, a DIVC syndrome, difficult to diagnose and to treat, or fibrinolysis, much more rarely nowadays, owing to the almost routine use of antiproteases. Sometimes, the check up of coagulation can be barely disturbed and local abnormalities in biological hemostasis which are still not well understood, are invoked in order to explain the hemorrhage.

Blood Cell Count↗
PubMed1977

Detecting the early stages of osteomalacia with the intravenous vitamin D test.

Studies of calcium levels in 400 elderly patients in a hospital geriatric unit showed that many patients (42 percent) had hypocalcemia when referred to the unit and that the incidence of hypocalcemia rises proportionately with advancing age; however, in men, the frequency decreases after age 90. Although hypocalcemia is caused by vitamin D deficiency in a number of patients, in most it is caused by malnutrition. The intravenous vitamin D tests is a simple and reliable procedure for differentiating hypocalcemia due to specific vitamin D deficiency from that due to other causes. We suggest that a 15 percent rise in the serum phosphate level after the intravenous administration of 40,000 units of vitamin D3 indicates the presenceof osteomalacia. Little is known about the sequence of development of detectable bone changes and disturbance of serum calcium, phosphate, and alkaline phosphatase levels in the natural course of osteomalacia. Early treatment of osteomalacia is simple and very rewarding. No effort should be spared in detecting it as soon as possible.

Aged↗
PubMed1976

Characterization of the RNA transcribed in vitro from native mammalian DNA by Escherichia coli RNA polymerase.

High-molecular-weight native mouse DNA was transcribed with Escherichia coli RNA polymerase under low salt conditions, and the nature of the DNA sequences transcribed determined by molecular hybridization. The results indicated that E. coli RNA polymerase does not transcribe the sequences in native mouse DNA randomly under these conditions. First, hybridization with a large excess of mouse DNA showed that no more than 5% of the RNA synthesized had been transcribed from repeated sequences in the DNA. Second, hybridization with tracer amounts of labelled non-repeated mouse DNA indicated that the bulk of the RNA had been transcribed from less than 1% of the non-repeated sequences and only about 10% had been transcribed from a further 25% of these sequences; the remaining non-repeated sequences in the DNA, amounting to 50% of the genome, were not represented in the RNA synthesized in vitro to any detectable extent. Third, the proportion (40%) of complementary DNA transcribed from mouse-liver nuclear polyadenylated RNA which hybridized with the RNA synthesized in vitro was significantly greater than would have been expected if transcription had been random. The data have also been interpreted as indicating the presence of two types of initiation site for E. coli RNA polymerase in the non-repeated sequences in mouse DNA. The frequencies of their occurrence have been calculated to be one per 150 000 base-pairs and one per 500 base-pairs, respectively.

Animals↗
PubMed1976

A class of chromatin particles associated with nonhistone proteins.

Unfixed nucleoproteins may be banded isopycnically in metrizamide (2(3-acetamido-5-N-methylacetamido-2,4,6-triiodobenzamido)-2-deoxy-D-glucose) according to the protein/nucleic acid ratio. Unsheared or lightly sheared chromatin bands sharply (p=1.2 g/ml); it has a protein/DNA ratio of 1.4. Chromatin sheared by sonication to approximately 350 base pairs of DNA contains two components with protein/nucleic acid ratios of approximately 1.3 (p=1,185 g/ml) and 2 (p=1.245 g/ml). When chromatin is digested exhaustively with staphylococcal nuclease, two density components are found, one with a protein/DNA ratio of 1.5 (p=1.21 g/ml), the other with a protein/DNA ratio of 2 (p=1.24 g/ml). In both instances the denser particle (p=1.24 g/ml) contains nearly all the nonhistone proteins, while both dense and light fractions contain histones in similar amounts. The base sequence complexity of DNA from the fractions is not distinguishable from that of total DNA and there is no evidence of any concentration of sequences complementary to polysomal polyadenylated RNA molecules.

Animals↗
PubMed1976

[Evaluation of orthodontic cases by means of key-punch cards. 3. Data from follow-up examinations].

484 orthodontic patients were subjected to follow-up examination. The kind of treatment, the evaluation and the factors that are of importance to continuing successes and recurrences, respectively, are described. It is pointed out that the present communication and the two previous ones aim at illustrating that the orthodontic practitioner is able to document and evaluate his cases easily with the aid of key-word cards.

Activator Appliances↗
PubMed1975

Chromatin-associated RNA content of heterochromatin and euchromatin.

Chromatin from TLT hepatoma cells, mouse liver cells, and mouse brain cells was fractionated by differential centrifugation into a pellet, enriched with heterochromatin, and a supernatant, enriched with euchromatin. The pellet was found to contain more than twice as much of a particular species of chromatin-associated RNA per milligram chromatin DNA as did the supernatant. This chromatin-associated RNA was also found to be associated with the transcriptionally inactive chromatin of mature avian erythrocytes. Bull sperm, whose genome is known to be completely inactive, was used as the source in the preparation of sperm heads. Bull sperm head RNA appeared to consist of a single, low molecular weight species which migrated on polyacrylamide gels at a rate just slightly slower than the aforementioned chromatin-associated RNA. The results are interpreted as indicating that this chromatin-associated RNA is more prevalently associated with the heterochromatic fraction of chromatin. It is postulated that this chromatin-associated RNA might constitute a structural component of heterochromatin.

Animals↗
PubMed1975

Control of transcription of the globin gene.

This report provides a more rigorous proof of previous findings that the RNA transcribed in vitro from the chromatins of different organs shows different sequence specificities. Here the particular case of the globin gene is considered for a comparison of embryonic mouse liver chromatin and mouse brain chromatin using the reverse transcriptase cDNA copy of globin 9S m RNA as a definitive probe. It can be shown that globin sequences are transcribed in vitro from embryonic liver chromatin and not brain chromatin. This specificity in liver chromatin can be reconstituted after dissociation of the structural elements of the chromatin. It can be shown that the non-histone protein fraction of liver chromatin can confer specificity for the transcription of globin sequences from brain chromatin which otherwise lacks this ability. Preliminary results are described with the Friend cell system, in which haemoglobin synthesis can be induced in vitro in the presence of dimethylsulphoxide.

Animals↗
PubMed1975

A kinetic estimation of base sequence complexity of nuclear poly(A)-containing RNA in mouse Friend cells.

Complementary DNA (cDNA) has been transcribed by viral reverse transcriptase from poly(A)-containing nuclear RNA prepared from growing mouse Friend cells (clone M2). Annealing experiments with this cDNA have demonstrated that a large proportion of the poly(A) tracts in M2 cell nuclear RNA are adjacent to RNA sequences which are transcribed from nonrepetitive DNA in the mouse genome. The kinetics of hybridization of cDNA to template RNA indicate that nuclear poly(A)-containing RNA consists of at least two abundance classes, the more complex of which is transcribed from approximately 3 percent of the genome. Thus there are at least 5 times more unique DNA sequences represented in nuclear polyadenylated RNA than in polysomal polyadenylated RNA. Moreover, there is evidence for posttranscriptional mechanisms which alter the relative concentrations of some (at least) gene transcripts between nucleus and cytoplasm.

Adenine Nucleotides↗