Ribosomal RNA synthesis in the mycelium of Phycomyces blakesleeanus. High molecular weight RNA

Total RNA was extracted from 24 h old mycelia of Phycomyces blakesleeanus which had been grown in liquid culture. Heavy molecular weight RNA was fractionated on 2.6% polyacrylamide gels. 1. The main cytoplasmic ribosomal RNA fractions had molecular weights of 1.34 and 0.72-16(6). 2. [3H]Uridine pulse labelling of cultures revealed an initial ribosomal RNA precursor of molecular weight 2.5-10(6). 3. An intermediate precursor for the 1.34 - 10(6) dalton peak was found, having a molecular weight of 1.6-10(6). 4. Pulse-chase experiments, using [3H]methionine, showed the flow of synthesis as being (see article). 5. Mature 0.72-10(6) dalton RNA appeared prior to the 1.34-10(6) dalton RNA but no immediate precursor for it was detected.

Enzymatic removal of H-2 alloantigens from the surface of P815-(X2) mouse tumor cells

After treatment with papain (6 mg/ml) for 1 h, P815 tumor cells became resistant to complement-mediated lysis by mouse alloantibodies of different specificities. Immunofluorescence and absorption studies indicated that this resistance was associated with removel of the corresponding antigenic determinants from the cell surface. In contrast, papain-treated tumor cells were fully susceptible to lysis by rabbit antiserum against P815 cells, indicating a) no alteration of the membrane sensitivity to complement damage, and b) a dissociation between structure and/or localization of allo- and xenoantigens. Papain-treated cells were also completely resistant to lysis by cytolytic T lymphocytes (CTL) during the first 60 min after completion of the enzyme treatment. Susceptibility to lysis by either CTL or alloantibody and complement reappeared within a few hours after incubation in culture medium and was virtually normal by 6 h. Treatment of P815 cells with trypsin (2 mg/ml) had no effect on either humoral or cellular lytic activities.

Quantitative determination of sex hormone-binding globulin capacity in the plasma of normal and diabetic pregnancies

Sex hormone-binding globulin (SHBG) capacity was measured in a longitudinal study in plasma samples from normal subjects, diabetics, and gestational diabetics and throughout pregnancy, together with unconjugated plasma estradiol. In normal women SHBG capacity (expressed in ng DHT bound per ml of plasma) increased from 23.7 +/- 13.7 (SD) in the 5-8th week period, to 74.5 +/- 20.7 in the 17-20th week period, and to 102 +/- 24 in the 37-40th week period. In diabetics the SHBG capacity for the same periods of time were respectively: 25.3 +/- 17.2, 83.1 +/- 29.1, and 111.6 +/- 22.6. Plasma levels of unconjugated estradiol were 55% higher in the diabetics than in the normal subjects in the second half of gestation, as reported in detail in another publication. From the imbalance between the close to normal SHBG capacity and the higher plasma levels of unconjugated estradiol in the diabetics, it is suggested that the unbound, i.e., metabolically active, fraction of plasma estradiol reaches higher levels in diabetics than in normal subjects in the second half of gestation.

A fine structure study of human thymus

A study of the fine structure of human thymus, including normal hyperplastic and with thymoma, is reported in this paper. There is increasing experimental evidence that thymic epithelial cells are a source of hormone. It is, therefore, of interest that we found epithelial cells containing intravesicular cytoplasmic material that reacted with silver methenamine as do mucoproteins. Similar material, possibly extracellular, was seen in close contact with lymphocytes and macrophages in the thymus. The results suggest a possible mechanism for epithelial cell/lymphocyte interaction. Some epithelial cells also showed phagocytic features and all appear to play a structural role. The presence of nuclear pockets was noted within lymphocyte nuclei.

Generation of cytotoxic T lymphocytes in vitro. V. Response of normal and immune spleen cells to subcellular alloantigens

Subcellular particulate membrane fragments prepared from murine lymphoid or tumor cells were used as a cell-free antigen source in order to stimulate the generation of cytolytic thymus-derived effector cells (CTL) in vitro. When cultivated with normal spleen cells as a source of responding lymphocytes, particulate antigen preparations induced only low CTL activities; in contrast, virtually normal responses were observed when immune spleens were used as a source of responding cells. In both cases, results were compared to those responses obtained with intact irradiated (1000 rads) normal spleen cells as stimulating antigen. The effector cells generated with particulate antigen preparations (obtained either by hypotonic shock or by sonication) were shown to be T cells and were characterized with regard to the kinetics of their response and their dose-activity relationship. It was also shown that the responses observed were specific, both at the level of initiation and at the effector level. The results obtained suggest that there exists a fundamental difference between normal and alloimmune spleen cells in their ability to respond in vitro to stimulation by subcellular antigen preparations.

[Proceedings: Sulpiride effects on plasmatic gonadotropins in women (author's transl)]

The study of longitudinal evolution of plasmatic gonadotropins in women receiving sulpirid, a psychotropic drug with a strong anti-ovulatory effect, shows the coexistence of anovulation and the peristance of a physiological pattern of gonadotropins during the first cycle of treatment. It also shows the persistance of LH peaks comparable to preovulatory levels more than one year after the initiation of therapy. However, the basal line became very unsteady. This study suggests the presence of two types of perturbations with sulpirid. A hypothalamic-hypophyseal mild action and, an ovarian resistance to gonadotropins resulting from the hyperprolactinism induced by sulpirid.