Is trisomy cause or consequence of murine T cell leukemia development? Studies on Robertsonian translocation mice

Trypsin-Giemsa banding studies on T cell leukemias induced in Robertsonian translocation mice by dimethylbenz[a]anthracene and Moloney leukemia virus show a trisomy of chromosome 15 even in cases in which chromosome 15 has undergone centromeric fusion with chromosomes 1, 5, or 6. These results suggest that the duplication of gene(s) located on chromosome 15 is of critical importance for murine T cell leukemia development.

Nonrandom chromosome changes involving the Ig gene-carrying chromosomes 12 and 6 in pristane-induced mouse plasmacytomas

The karyotypes of pristane-induced mouse plasmacytomas were studied by G banding. Only primary tumors or early passage generations were analyzed. In contrast to murine T cell leukemias that showed a regular trisomy of chromosome 15, all plasmacytomas showed a consistent translocation of the distal part of chromosome 15 to either chromosome 6 [rcpT(6;15)] or 12 [T(12;15)]. The specific breakpoints were at 6C, 15D3/E ro D2/3 and 12F2. Early passage generations often showed a mixed population with two different translocations, suggesting polyclonal origin. Considered together with the known karyotypic features of murine and human lymphomas, these findings support the theory that the nonrandom chromosomal changes in lymphoproliferative malignancies are associated with the type of the target cell, rather than with the etiological agent. Moreover, the involvement of the chromosomes known to carry the heavy chain (12) and the light chain (6) determinants, respectively, raises the question of whether the translocations may be related to the DNA level rearrangements known to occur during the differentiation of normal plasma cells.

Mucosubstances of rabbit granulocytes studied by means of electron-microscopic radioautography and X-ray microanalysis

Rabbit bone marrow cells have been studied by means of light- and electron-microscopic radioautography and X-ray microanalysis. Carrier free sulfuric acid was used as the radioactive precursor in this experiment. Immature granulocytes showed more active incorporation than mature ones. Silver grains were observed in the Golgi apparatus and granules in three kinds of granulocytes. Electron-microscopically, immature granules showed the incorporation of inorganic sulfate, while mature ones did not. Sulfur was detected in all kinds of granules of the three granulocyte types by X-ray microanalysis. It is concluded that incorporated inorganic sulfur may be utilized for the synthesis of acid glycosaminoglycans and the sulfur detected by X-ray microanalysis may be that contained in the acid glycosaminoglycan. The sulfur detected in the specific granules of the heterophil probably derives from proteins or polypeptides incorporating sulfur containing amino acids.

The identification of human H-Y antigen and testicular transformation induced by its interaction with the receptor site of bovine fetal ovarian cells

beta 2m(-), HLA (-) Daudi human male Burkitt lymphoma cells excreted a group of protein subunits that shared three distinctive characteristics; their conspicuously longer half-lives compared to more hydrophilic Daudi excreted proteins, their tendency to form progressively larger polymers by means of interchain disulfide bridges, and the extreme hydrophobicity of these polymers. The plasma membrane of extragonadal somatic cells absorbed 1.2 to 2.8% of these hydrophobic proteins. The unoccupied H-Y receptor sites residing on the plasma membrane of bovine fetal ovarian cells, on the other hand, selectively absorbed polymers of 18,000 mol. wt. subunits, and this antigen-receptor interaction, if allowed to continue for five days, induced the formation of tunica albuginea and seminiferous tubules in bovine XX embryonic indifferent gonads. In this manner, human H-Y antigen excreted by Daudi cells has functionally been identified as a series of polymers derived from 18,000 mol. wt. subunits. While, the H-Y antigenic determinants were retained even by the largest polymeric form that became irreversibly water insoluble, the receptor binding activity was shown only by 36.8% of the available polymeric forms of 18,000 mol. wt. subunits, at the most. Nevertheless, once bound to the receptor site, these polymers were rapidly reduced to the monomeric form on the plasma membrane of bovine fetal ovarian cells. Accordingly, the 18,000 mol. wt. monomer might actually represent the functional form of H-Y antigen.

Evidence for antigenic distinctness of the Epstein--Barr virus-determined nuclear antigen and the Herpesvirus papio-determined nuclear antigen

Previous serological evidence indicated that Epstein--Barr virus-determined nuclear antigen (EBNA) has cross reactive components with the herpesvirus papio-determined nuclear antigen (HUPNA) and, in addition, it has distinct components of its own, not present in HUPNA. In the present study, this hypothesis was studied by absorption experiments. Absorption of anti-EBNA positive human sera with EBNA abolished both anti-EBNA and anti-HUPNA reactivity. Absorption with HUPNA removed all anti-HUPNA reactivity but did not reduce anti-EBNA to any detectable degree, thus confirming the hypothesis.

Non-random duplication of chromosome 15 in murine T-cell leukemias induced in mice heterozygous for translocation T(14:15)6

Trisomy of chromosome 15 is a highly regular feature of murine T-cell leukemogenesis. We have studied the chromosomal constitution of 7,12-dimethylbenza(a)anthracene (DMBA)-induced T-cell leukemias in C57BL X CBAT6T6 F1 mice. The CBAT6T6-derived chromosome T(14:15)6 was regularly duplicated whereas the C57BL-derived normal chromosome 15 was only present in one copy. It was concluded that the gene(s) that tend to duplicate in parallel with the neoplastic transformation of the prothymocyte to an overt leukemic cell have a greater chance of duplicating and/or may have a stronger promoting effect on leukemogenesis if stronger promoting effect on leukemogenesis if located on the CBA-derived, structurally rearranged T(14:15)6 than the corresponding genes located on the C57BL-derived normal chromosome 15.

Detection of a nuclear antigen in Herpesvirus ateles-carrying marmoset lines by the acid-fixed nuclear binding technique

In vitro binding of a Herpesvirus ateles (HVA)-associated soluble antigen to amphibian erythrocyte nuclei was demonstrated by the acid-fixed nuclear binding technique in combination with anticomplement immunofluorescence. Incubation of concentrated salt-extracted soluble antigens derived from HVA-carrying marmoset lines with methanol/acetic acid-fixed erythrocytes of frogs and salamanders resulted in a brilliant nuclear fluorescence after exposure to a live virus-boostered, anti-HVS-positive squirrel monkey serum. Anti-HVS-negative sera did not stain. The activity of the positive serum could be abosrbed completely with extracts of HVA-carrying cells but not with Epstein-Barr virus-carrying or Herpesvirus papio-carrying cells. The HVA-associated antigen was also present in lytically HVA-infected marmoset kidney cells.

In vitro studies of gonadal organogenesis in the presence and absence of H-Y antigen

In a very strict sense, the primary (gonadal) sex of mammals is determined not so much by the presence or absence of the Y but the expression or nonexpression of the evolutionary extremely conserved plasma membrane H-Y antigen. The central somatic blastema of embryonic indifferent gonads contains one cell lineage characterized by the possession of S-F differentiation antigen that differentiates into testicular Sertoli cells in the presence of H-Y and into ovarian follicular (granulosa) cells in its absence. This cell lineage appears to play the most critical role in gonadal differentiation. Whether or not testicular Leydig cells and ovarian theca cells are similarly derived from the common cell lineage has not been determined. Nevertheless, if given H-Y antigen, presumptive theca-cell precursors of the fetal ovary acquire hCG (LH?)-receptors-the characteristic of fetal Leydig cells.

Colicin E3 is an endonuclease

It was confirmed by polyacrylamide gel electrophoresis that isolated 16S rRNA was cleaved by the active component (protein A) or the active fragment (T2A) of colicin E3. However, the degradation was random, in contrast with the specific cleavage observed in the interaction of colicin E3 with ribosomes. Furthermore, the active component and the active fragment had low activities, and far greater amounts of these materials were required for degradation of the isolated rRNA than for ribosome inactivation. The degradation of rRNA cannot be due to contaminating ribonuclease(s), but is due to colicin E3 itself, because of the following facts. (1) Protein B of colicin E3, which specifically inhibits the ribosome-inactivating activity of colicin E3, inhibited the degradation of rRNA. (2) Protein B of colicin E2, which inhibits the action of colicin E2 but not of colicin E3, failed to inhibit the degradation of rRNA. (3) The activity appeared in the peak of protein A or fragment T2A, respectively, when they were rechromatographed on Sephadex G-75.

Ultrastructural localization of glycogen in the granulocytes of normal rabbit bone marrow

The glycogen of rabbit granulocytes has been studied in glutaraldehyde and osmium tetroxide fixed bone marrow by the periodic acid-thiocarbohydrazide-silver proteinate procedure (PA-TCH-SP). The PA-TCH-SP procedure involved the staining of intracytoplasmic glycogen more densely than the routine lead citrate staining. The PA-TCH-SP procedure demonstrated the intracytoplasmic glycogen in all three kinds of granulocytes. Though a sequence of intensity was observed in each stage of cell maturation, intracytoplasmic glycogen increased generally in accordance with cell maturation in the granulocytes. Functional significance of the glycogen in the granulocytes was discussed in relation to its staining. A very weak reaction in the granules of the granulocytes was described in relation to their contents.

Chromosome changes (trisomy 15) in murine T-cell leukemia induced by 1,12-dimethylbenz(a)anthracene (DMBA)

The banding pattern of DMBA-induced leukemias in C57BL/6 mice revealed a very constant chromosome pattern: the presence of trisomy 15 in almost all leukemic cells. This finding strongly suggests that chromosome 15 trisomy is the first detectable specific chromosome change associated with the development of DMBA-induced T-cell lymphomas. A similar association was previously shown with regard to development of radiation-leukemia-virus-induced T-cell lymphoma. It is conceivable that in tumors of diverse etiologies common cytogenetic changes may appear in the same common target-cell precursor, by a process of the "convergent microevolution" type.

Physical properties of androgen receptors in brain cytosol from normal and testicular feminized (Tfm/y hermaphrodite) mice

Our previous results had shown that brain cytosol from androgen-insensitive, testicular feminized (Tfm/y) mice contains a reduced amount (20-25%) of androgen receptors, compared to normal female or castrated male mice, with unchanged affinity for dihydrotestosterone (DHT). We have now used various physicochemical techniques to ask whether there is a qualitative difference between these residual receptors and those in normal brain. When androgen receptors labeled with [3H]DHT in concentrated crude brain cytosol were analyzed by density gradient centrifugation and Agarose gel filtration in buffers containing 0.4-0.5 M KCl, Tfm/y receptors appeared to be smaller and more symmetrical than those from their normal siblings; however, if wild-type receptors were partially purified or prepared from slightly more dilute homogenates, their properties approached those of Tfm/y receptors in crude cytosol. This suggested that receptor molecules in concentrated cytosol from normal mice were aggregated to a greater extent than were those from the mutant. The molecular weight (54,000) and axial ratio (3:1 for prolate or oblate ellipsoid) calculated for Tfm/y receptors, therefore, may provide estimates for normal receptors as well. By DNA-cellulose chromatography, Tfm/y and female cytosol receptors were both resolved into two components, eluting at about 0.13-0.15 and 0.22-0.24 M NaCl. On DEAE-cellulose columns, both were eluted as a single major species at approximately 0.08-0.10 M KCl. Thus, excluding their state of aggregation, presumably resulting from their different concentrations in crude cytosol, Tfm/y and normal receptors were substantially identical as concerns the physical parameters examined in this study.

A modified wire-loop method for quantitative electron microscopic radioautography

A simplified method of emulsion coating and development for quantitative electron microscopic radioautography without any special instrument in introduced. Seven grids carrying ultrathin sections are attached to a glass block with double-coated Scotch tape. They are coated with a wire-loop, 2.5 cm in diameter. Ten glass blocks are then stuck on a slide, exposed, developed, fixed and stained simultaneously. Employing this method, the emulsion coating and the following procedures are easily accomplished under an identical condition.

Chromosome changes (trisomies #15 and 17) associated with tumor progression in leukemias induced by radiation leukemia virus

An experimental system was developed that permitted nonrandom chromosome changes that occur in radiation leukemia virus (RadLV)-induced lymphomas to be followed during tumor progression. RadLV variant-induced preleukemia and leukemia cells originating from female inbred C57BL/6 mice were injected into male animals of the same strain. Since all donors were females and all recipients were males, the sex chromosome complements (XX and XY) were used to distinguish the preleukemia and leukemia cells from those of host origin. The G-banding analysis revealed that more than 50% of animals that were inoculated with preleukemia cells and that developed leukemia possessed tumor stem-lines of 41 chromosomes with a tristomy of chromosome #15. In animals inoculated with overt leukemia cells and in which tumor progression occurred, the G-banding an additional trisomy of chromosome #17. The cytogenic data strongly suggested that the trisomy of chromosome #15 was the first specific tumor-associated chromosome change that occurred in the process of conversion of RadLV-induced preleukemia cells to fully autonomous tumor cells.

In vitro and in vivo effect of PC 904, a new broad-spectrum penicillin, on ocular strains of Pseudomonas aeruginosa

The in vitro and in vivo activities of PC 904 were tested against Pseudomonas aeruginosa isolated from infected eyes and were compared with carbenicillin and gentamicin. By the microtiter plate method, we tested 30 strains of P. aeruginosa in vitro; PC 904 was very active against 29, but one strain was resistant. In a comparative study, PC 904 was more active than carbenicillin but less active than gentamicin. In vivo tests were conducted on rabbit corneas infected with a strain of P aeruginosa isolated in El Salvador. At moderate and high dosage levels, PC 904'S efficacy was comparable to carbenicillin's but much less than gentamicin's. When tested for ocular toxicity, the subconjunctival administration of PC 904 was well tolerated. The drug's greater activity in vitro than in vivo was probably due to its high serum-binding capacity.