Samples of tRNA isolated from the cell sap of full-term human placenta were found to have a low capacity for accepting amino acids in the presence of partially purified synthetase preparations made from placental or rat liver cell sap. Gel electrophoresis of placental tRNA showed that part of this could be accounted for by gross degradation. The proportion of chargeable tRNA carrying amino acids was estimated by periodate oxidation followed by stripping and then charging with labeled amino acids. Only 50% of chargeable placental tRNA was in the charged state when isolated, whereas 87% of freshly isolated rat liver tRNA was found to be charged with amino acids. A fraction from placental cell sap was shown to have tRNA nucleotidyltransferase activity. When placental tRNA was incubated with this fraction and [3H]ATP or [3H]CTP, ATP was incorporated into about 12% of the tRNA molecules and CTP into 5-7%. When rat liver tRNA was used in place of placental tRNA, [3H]ATP was incorporated into less than 5% of the tRNA molecules. By using snake-venom diesterase over short periods of incubation, it was confirmed that the ATP had been incorporated terminally as AMP into the placental tRNA. These observations show that, in contrast to rat liver tRNA, tRNA prepared from human placenta is poorly charged with amino acids, many of the molecules lack the acceptor trinucleotide and there is extensive degradation beyond this stage.

Amino Acyl-tRNA Synthetases↗

PubMed1976

In vitro response of subpopulations of human lymphocytes. II. DNA synthesis induced by anti-immunoglobulin antibodies.

A significant and constant increase in DNA synthesis was observed in human lymphocytes cultured in the presence of purified anti-immunoglobulin antibodies specific for human IgG, IgA, and IgM. This has been found in cultures of lymphocytes isolated from blood, tonsils, spleen, and lymph nodes. The optimal culture conditions for blood and tonsil lymphocytes were determined. As a rule 6-day cultures containing 2 x 10(6) cells/ml and 100 mug/ml of antibody yielded the highest 3H-thymidine uptake. Purified T cell cultures could not be stimulated, whereas a low response could be observed in most of the purified B cell cultures. Optimal culture conditions were the same for the B and total tonsil lymphocytes. However, when the purified B cells were totally depleted of T cells, no response was observed. A T and B cell synergy has been demonstrated by supplementing B cell cultures with purified T cells, whether treated or not with mitomycin. These experiments indicated a permissive and potentiating effect of T cells on the B cell response. Cultures containing mitomycin-treated B cells and purified T cells (mB + T) could be stimulated by a-Ig, thus indicating a T cell proliferation. In keeping with this finding was the observation of an increased response of total lymphocytes supplemented with T cells but not with B cells. Adherent cells are necessary for an optimal response to a-Ig; they enhanced the B cell proliferation observed in (Tm + B) cultures and suppressed the response of T cells in (T + Bm) cultures.

Antibodies, Anti-Idiotypic↗

PubMed1976

Concanavalin A-activated suppressor cells in normal human peripheral blood lymphocytes.

A 24-hr preincubation of human peripheral blood lymphocytes in the presence of Con A renders them suppressive for the response of untreated cells to soluble antigens, allogeneic cells and Con A.

Adult↗

PubMed1975

Isolation and in vitro translation of human placental lactogen messenger RNA from human term placenta.

A messenger activity for HPL was identified in normal human term placentas. The mRNA was translated in rabbit reticulocyte cell-free system. The HPL synthesized was quantified by a specific immunoprecipitation and further identified by electrophoresis on sodium dodecyl sulfate polyacrylamide gel. The HPL synthesized in the reticulocyte lysate exhibited a molecular weight between 20,000 and 22,000 daltons similar to the active hormone. The messenger RNA activity for HPL corresponded to a sedimentation coefficient of 11-12 S. Furthermore the messenger activity for HPL was preferentially associated with membrane bound polyribosomes than with free polyribosomes.

Cell Membrane↗

PubMed1975

Smoking, human placental lactogen and birth weight.

Human placental lactogen (HPL) was measured in 525 serum samples from 144 pregnant women and related to smoking habits and the birth weight of their infants. Women smoking during pregnancy were found to have a level of HPL significantly lower than the non-smokers (p less than 0.05). A significant correlation between HPL and birth weight was found (r=0.38); p less than 0.001) which remained significant when smoking was held constant (r=0.35; p less than 0.001). There was no relationship between birth weight and smoking when HPL was held constant.

Birth Weight↗

PubMed1975

Glutamic-pyruvic transaminase activity related to red blood cell age.

Red blood cell glutamic-pyruvic transaminase (GPT) phenotypes and catalytic activities were studied in normal subjects and in patients with various hemolytic syndromes associated with reticulocytosis. To assess the effect of cell age of GPT activity, young cells were separated from older cells by centrifugation, and the catalytic activities were compared. In normal blood, there was a progressive fall in GPT activity from the top layer (younger cells) to the bottom layer (older cells), with a mean ratio of 1.90 plus or minus 0.42. Similarly, in the blood of patients with reticulocytosis, the enzyme activity of the reticulocyte-rich layer was higher than that of the layer containing older cells (mean ratio 1.94 plus or minus 0.95).

Alanine Transaminase↗

PubMed1975

Activity of liver fructose diphosphatase from chick embryos treated with aminoguanidine sulfate.

Injection of chick embryos with aminoguanidine sulfate (AGS) on the fourth day of incubation resulted in a decreased specific activity of liver fructose diphosphatase (FDPase) prior to hatch time. This decreased FDPase specific activity was found to be the consequence of increased levels of an enzyme inhibitor (adenosin 5'-monophosphate) rather than a specific repression of enzyme synthesis.

Adenosine Monophosphate↗

PubMedDate not supplied

[The Kasabach-Merritt syndrome with pancreatic localization in a newborn infant].

The case of a neonate with a large pancreatic hemangioma belonging to the Kasabach-Merritt syndrome is reported. Selective embolization of one of the main vessels originating from the gastroduodenal artery resulted in a progressive increase of blood platelet levels and in a concomitant change in the hemangiomatous structure at ultrasound examination, as well as in a subsequent acceleration of somatic growth. At 8 months of age, there were no more clinical, radiological, ultrasonographic or biological signs of the hemangioma. This case report emphasizes the interest of embolization in the Kasabach-Merritt syndrome.

Embolization, Therapeutic↗

PubMedDate not supplied

[X-ray computed tomography in venous pathology].

After presenting the tomodensitometric semiology of venous thromboses in various territories, the authors define its indications. It is essentially in deep territories, head, chest and abdomen that the CT-Scan is used to study and diagnose unrecognized thromboses as well as determine the venous repercussion of various neighboring ailments. The respective place of the CT-Scan, ultrasonography and various phlebographies is analyzed.

Humans↗

PubMedDate not supplied

[Magnetic resonance in venous pathology].

After a brief and schematic reminder of the physical bases of I.R.M. in the study of blood vessels, the results and indications are presented in various venous territories: superior and inferior vena cava, hepatic, cerebral and peripheral veins. Venous and peri-venous diseases are simply emphasized. The advantages of the technique, multi-dimensional study without contrast nor radiation, are emphasized and compared with the drawbacks depending essentially on the cost and the length of the tests.

Cerebral Veins↗