A technique for monitoring respiratory responses in guinea pigs

A piezoelectric crystal was used to detect respiration rates and pulmonary retractions of guinea pigs in response to intratracheal administration of histamine. Voltage output from the crystal was displayed on a recorder for visual processing and interfaced to a microcomputer for automatic data processing. Using intratracheal instillation of histamine, this system accurately reproduced the visual observations of respiratory responses in guinea pigs.

Cell surface DNA in immunosuppression in AKR leukemia

Spleen cells from leukemic AKR mice contain nonspecific T suppressor cells that suppress the in vitro anti-SRBC responses of normal AKR spleen cells. The suppression is abrogated by pretreatment of the leukemic cells with DNase. Cells with surface DNA can be enriched by treatment with anti-DNA antibodies and removed on anti-Ig columns. Even though there is a 10-fold enrichment in suppression by the surface DNA-positive cells (DNA+), the depleted population (DNA-) still suppresses with an efficiency comparable to the unfractionated spleen cells. Pretreatment with anti-I-J antiserum and separation on columns neither enriches nor depletes suppressor cells. Fractionating leukemic spleen into 4 populations of cells by sequential treatment with anti-DNA and anti-I-J with separation on appropriate columns, resulting in 4 populations (DNA+/I-J-, DNA+/I-J+, DNA-/I-J+, and DNA-/K-J-), revealed that the DNA+/I-J- cells that comprise ca. 15% of the total are the most potent suppressors. The DNA+/I-J+ cells that comprise ca. 2% of the cells are less efficient and their suppression is not sensitive to DNase. The DNA-/I-J+ population (ca. 10% of the total) are also poor suppressors. The remaining cells, which are DNA-/I-J-, do not act as suppressors. When small numbers of any 2 of the 4 fractions were added together, it was found that the DNA+/I-J- cell can interact with the DNA+/I-J+ and the DNA-/I-J+ cells but not the DNA-/I-J- cells to give enhanced suppression.

Cell surface DNA in immunosuppression in AKR leukemia

Spleen cells from leukemic AKR mice contain nonspecific T suppressor cells that suppress the in vitro anti-SRBC responses of normal AKR spleen cells. The suppression is abrogated by pretreatment of the leukemic cells with DNase. Cells with surface DNA can be enriched by treatment with anti-DNA antibodies and removed on anti-Ig columns. Even though there is a 10-fold enrichment in suppression by the surface DNA-positive cells (DNA+), the depleted population (DNA-) still suppresses with an efficiency comparable to the unfractionated spleen cells. Pretreatment with anti-I-J antiserum and separation on columns neither enriches nor depletes suppressor cells. Fractionating leukemic spleen into 4 populations of cells by sequential treatment with anti-DNA and anti-I-J with separation on appropriate columns, resulting in 4 populations (DNA+/I-J-, DNA+/I-J+, DNA-/I-J+, and DNA-/K-J-), revealed that the DNA+/I-J- cells that comprise ca. 15% of the total are the most potent suppressors. The DNA+/I-J+ cells that comprise ca. 2% of the cells are less efficient and their suppression is not sensitive to DNase. The DNA-/I-J+ population (ca. 10% of the total) are also poor suppressors. The remaining cells, which are DNA-/I-J-, do not act as suppressors. When small numbers of any 2 of the 4 fractions were added together, it was found that the DNA+/I-J- cell can interact with the DNA+/I-J+ and the DNA-/I-J+ cells but not the DNA-/I-J- cells to give enhanced suppression.

The expression of histocompatibility-2 antigens on hemopoietic stem cells

Antisera directed against histocompatibility-2 antigens of the mouse suppress the formation of spleen colonies by pluripotent hemopoietic stem cells. Of antisera which are specific for subregions of the H-2 complex, only those which contain anti-H-2K or anti-H-2D activity are effective. Specific anti-Ia sera do not react with the stem cell. If the titer of the CFU-s suppressive effect of the antisera is compared to their toxicity to spleen lymphocytes, it can be concluded that CFU-s express antigens in the same density as spleen lymphocytes. The amount of H-2 antigens expressed on the surface of CFU-s is independent of its rate of proliferation.

Leukemia in AKR mice: a defined suppressor cell population expressing membrane-associated DNA

Leukemic AKR mouse spleen cells suppress normal AKR anti-sheep erythrocyte antibody responses in vitro. Treatment of leukemic spleen cells with DNase I prior to coculture with normal AKR cells abrogates their suppressive ability. Treatment of leukemic cells with a wide range of DNase I concentrations has no effect on the viability of these cells as measured by incorporation of [(3)H]thymidine or by eosin dye exclusion. When the activating divalent cations required for DNase I action are functionally removed in the enzyme treatment medium by chelation with EDTA, the ability of DNase I to abrogate suppression is abolished. Furthermore, the effects of DNase I in overcoming suppression are not able to be mimicked by trypsin, Pronase, or ribonuclease. These results are consistent with the existence of a population of cells in the leukemic spleen that expresses a form of membrane-associated DNA that functions in the suppression of normal antibody responses. The existence of such a population was shown by treating leukemic spleen cells with anti-single-stranded-DNA and then passing them through an anti-immunoglobulin immunoadsorption column. Approximately 15% of the leukemic cells are retained on the column and can be specifically eluted with the normal immunoglobulin. The cells of this enriched population when cocultured with normal spleen cells exhibit a 10-fold greater suppressive ability than unfractionated cells. Thus, there exists in the spleens of overtly leukemic AKR mice a population of cells expressing a form of DNA on their surfaces that in some manner is necessary for immunosuppression.

Traumatic rupture of the supramembranous urethra

We reviewed 38 patients treated by an immediate realignment of the urethra after a traumatic rupture by urethrography, panendoscopy and clinical assessment. Of these 38 patients 19 have not required urethral dilatation for 4 years or more and 26 for 2 years or more, thus accomplishing with 1 operation satisfactory urinary tract function without stricture. We believe that an immediate repair offers the best results to patients with minimum surgical procedures insofar as the formation of strictures is concerned. Evaluation of the interference with potency will have to await further study.

Functional development of the interacting cells in the immune response. III. Role of the neonatal spleen

Neonatal splenectomy and congenital absence of the spleen were shown to be associated with lack of primary IgM antibody synthesis, deficient bone marrow-thymus cell synergism. altered mitogen responsiveness and depressed homing patterns of thymocytes to the spleen. Using congenitally asplenic animals, altered B-T cell cooperation was manifest at the T cell but not B cell level. This correlated with the ability of thymus cells from either congenitally asplenic or neonatally splenectomized (NSx) animals to respond to the B cell mitogen lipopolysaccharide although there were no detectable Ig=ells present. To determine the role played by the spleen in the development of T cell function, NSx animals were given either irradiated or normal spleen grafts. Both irradiated and unirradiated grafts restored normal B-T cooperation and normal mitogenic responses of thymus cells. However, neither type of spleen graft was successful in restoring normal homing patterns to the spleen. It is concluded that the splenic microenvironment influences T cell maturation very early in life and that only some of the effects attributable to the absence of the spleen can be reversed by the reintroduction of this tissue as a graft.

Unregulated growth of murine leukemic cells and suppression of normal granulocyte growth in diffusion chamber cultures

The patterns of proliferation of C1498 mouse acute leukemic cells have been studied using the diffusion chamber technique of cell culture. These malignant cells grow to the same maximal cell concentration irrespective of initial cell input. Leukemic cells proliferate equally well with or without the stimulus of prior host irradiation. When cells cultured for several days are diluted to the original input concentration and recultured, they rapidly proliferate back to maximal cell number. All of these findings are in sharp contrast to the behavior of granulocytes from normal mouse marrow grown in the same culture system. Co-culutre of equal numbers of normal marrow cells and leukemic cells results in virtually complete inhibition of normal marrow cells and leukemic cells results in virtually complete inhibition of normal granulocyte growth. These experiments provide a means of studying malignant growth of leukemic cells, as compared to the controlled growth and differentiation of normal granulocytes, and mechanisms by which leukemic cells suppress normal granulocyte development.

Modulation of murine granulocyte proliferation in diffusion chamber cultures

Normal mouse marrow cells were cultured in Millipore diffusion chambers for long periods of time and at a variety of cell concentrations. All cultures showed a pattern of granulocyte proliferation characterized by logarithmic growth followed by prolonged stabilization of cell number starting a 7 days thereafter. The height of this "plateau" varied in relationship to the level of cell input and characteristically was far lower than the maximum cell density that can be maintained in this culture system. Additional studies showed that the plateau represented a steady state of granulocyte turnover and was not due to alterations in the diffusion chambers or the host mice. Regulatory mechanisms intrinsic to the cultured cell population appeared to play a primary role in maintaining this stable plateau. Modulation of granulocyte proliferation was partly due to increasing cell density; particularly with high input concentrations. In addition, differential cell counts suggested that critical changes in the relationship between immature and mature granulocytes partially accounted for this apparent autoregulation of cell growth. The plateau period in diffusion chamber cultures in many ways resembles granulocyte proliferation in normal mouse bone marrow and is a useful model for the study of regulatory functions in granulocytopoiesis.