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Biomedical subjects

A Singer

Publications and source records attributed to A Singer.

At least 343 records · Page 19Linked to original sources
PubMed1980

Colposcopy in the management of the pregnant patient with abnormal cervical cytology.

Thirty patients with abnormal cervical cytology had a colposcopy during pregnancy. Their management during and after pregnancy is described and supports the contention that the introduction of a colposcopy service safely permits a greater selectivity in management without recourse to operative intervention during pregnancy. In one patient a preclinical invasive squamous carcinoma of the cervix was diagnosed by colposcopy, and in another three, in whom colposcopy could not exclude the presence of invasion, a wedge biopsy under anaesthesia and two punch biopsies without anaesthesia had to be performed. In the remaining 26 patients, the possibility of invasion could be excluded by colposcopy and further treatment deferred until after pregnancy.

Cervix Uteri↗
PubMed1980

Popliteal artery branches: percutaneous transluminal angioplasty.

Percutaneous transluminal angioplasty of the branches of the popliteal artery was performed in six patients, two of whom also had femoropopliteal angioplasty. Dilatation was performed with catheters ranging from 5.5 to 7 French. None of the popliteal branch dilatations was performed with an inflated balloon. Excellent dilatation, as documented by angiography and Doppler ultrasound pressure recordings, was obtained in four cases and moderate and slight improvement in one case each. Two of the four patients with excellent results had prompt healing of toe amputations and are doing well at 19 and 22 months after angioplasty. In the other two patients with excellent results, below-knee amputation was necessary despite patency of the dilated segment in one. In the other patient with initially excellent results, reocclusion occurred 4 months after angioplasty. In the patients who had moderate and slight improvement on angiography and in distal pressures, no significant clinical course change occurred. No patient had clinical deterioration after angioplasty and no significant complications occurred.

Aged↗
PubMed1980

Cellular and genetic control of antibody responses. VIII. MHC restricted recognition of accessory cells, not B cells, by parent-specific subpopulations of normal F1 T helper cells.

Normal F1 helper T cell populations were analyzed under conditions in which the number of T cells was strictly limiting so that anti-hapten PFC responses to TNP-KLH increased linearly with increasing numbers of T cells. The slope of the response line is a measure of the helper activity of the added T cell population and reflects the number of helper T cells activated. In this way, the recognition and activation requirements of normal F1 helper T cell subpopulations were analyzed. It was determined that the F1 helper T cells specific for recognizing antigen in the context of the MHC determinants of only one parent specifically recognized those determinants expressed on accessory cells, but not on B cells. Indeed, each parent-specific F1 T cell subpopulation was only triggered by one parent's accessory cells; but once triggered, each parent-specific F1 T cell subpopulation was capable of activating either parent's B cells.

Animals↗
PubMed1980

Role of accessory cells in B cell activation. I. Macrophage presentation of TNP-Ficoll: evidence for macrophage-B cell interaction.

The importance of cell interaction for thymic independent antigen responses has not been widely appreciated. The present report demonstrates, however, that macrophage-B cell interaction may be an important feature of B ce-l activation for the response to at least one polysaccharide thymic independent antigen, TNP-Ficoll. Experiments were performed demonstrating that a strict accessory cell requirement exists for the thymic independent response to soluble TNP-Ficoll, and that such accessory cells are both adherent and phagocytic, that is, macrophages. It was further demonstrated that macrophages could be pulsed with TNP-Ficoll and that these pulsed macrophages could activate B cells to respond, but only if the pulsed macrophages were viable. Thus, one function that macrophages can fulfill in responses to TNP-Ficoll is the specific function of antigen presentation. Such presentation of TNP-Ficoll by macrophages to B cells suggests that the antigen may not be activating B cells directly, and raises the possibility that the interaction of B cells and macrophages might be genetically restricted.

Animals↗
PubMed1979

Cellular and genetic control of antibody responses. V. Helper T-cell recognition of H-2 determinants on accessory cells but not B cells.

Requirements for helper T-cell recognition of H-2 determinants expressed on adherent accessory cells and on B cells was individually assessed in the anti-hapten PFC responses to TNP-KLH. Complicating allogeneic effects were minimized or avoided by the use of helper T cells from normal F1 hybrids, parent leads to F1 chimeras, and F1 leads to parent chimeras. The results of both in vitro and in vivo experiments demonstrated that: (a) helper T cells are not required to recognize the identical H-2 determinants on both accessory cells and B cells; (b) helper T cells are required to recognize K or I-A region-encoded determinants expressed on accessory cells; (c) no requirement was observed in vitro or in vivo for helper T-cell recognition of B-cell-expressed H-2 determinants; and (d) no requirement was observed for H-2 homology between accessory cells and B cells. The absence of required helper T-cell recognition of the identical H-2 determinants on both accessory cells and B cells was demonstrated in two ways: (a) naive of KLH-primed (A x B)F1 hybrid helper T cells collaborated equally well with B cells from either parentA or parentB in the presence of accessory cells from either parent; (b) A leads to (A x B)F1 chimeric spleen cells depleted of accessory cells collaborated equally well with accessory cells from either parentA or parentB, even though the B cells only expressed the H-2 determinants of parentA. A requirement for helper T-cell recognition of K or I-A region-encoded H-2 determinants on accessory cells was also demonstrated in two ways: (a) (A x B)F1 leads to parentA chimeric spleen cells depleted of accessory cells collaborated with accessory cells from parentA but not parentB; and (b) (A x B)F1 leads to parentA chimeric helper T cells collaborated with normal F1 B cells only in the presence of parental or recombinant accessory cells that expressed the K or I-A region-encoded determinants of parentA. Although restricted in their ability to recognize H-2 determinants on accessory cells, it was demonstrated both in vitro and in vivo that (A x B)F1 leads to parentA chimeric helper T cells were able to collaborate with B cells from either parentA or parentB. In vitro in the presence of accessory cells from parentA, (A x B)F1 leads to parentA chimeric helper T cells collaborated equally well with B cells from either parent. In addition, the inability of (A x B)F1 leads to parentA chimeric helper T cells to collaborate with (B + accessory) cells from parentB was successfully reversed by the addition of parentA SAC as added accessory cells. In vivo, upon the addition of parentA accessory cells, (A x B)F1 leads to parentA chimeric helper T cells collaborated with parentB B cells in short-term adoptive transfer experiments.

Animals↗
PubMed1978

Sperm basic proteins in cervical carcinogenesis: Correlation with socioeconomic class.

Two types of basic protein, a histone and a protamine, were separated from single ejaculates of human sperm and a ratio between their contents in a given number of sperm established. The ratio varied widely in different males and correlated with ranking by social class: the lower the social class, the greater the proportion of protamine. Statistically similar correlations link social class with the incidence of venereal disease and the incidence of in-situ carcinoma of the cervix, both of which are epidemiological variables in squamous cervical cancer. The basic proteins of the sperm head, especially the protamines, may thus also have a role in the aetiology of squamous cervical cancer.

Carcinogens↗
PubMed1978

Cellular and genetic control of antibody responses in vitro. III. Immune response gene regulation of accessory cell function.

The possibility was investigated that Ir genes regulate the function of cells other than T or B cells in the primary IgM responses to the synthetic antigens trinitrophenylated poly-L-(Tyr,Glu)-poly-D,L-Ala--poly-L-Lys [TNP-(T,G)-A--L]and trinitrophenylated poly-,-(His,Glu)-poly-D, L-Ala--poly-L-Lys [TNP-(H,G)-A--L]. The primary responses of (B10 x B10.A)F(1) spleen cells to both antigens were abrogated by Sephadex G-10 passage, and restored by the addition of spleen adherent cells. The cell type in the spleen adherent cell population active in reconstituting the responses to TNP-(T,G)-A--L and TNP-(H,G)-A--L was a non-T, non-B, radiation-resistant, glass-adherent spleen cell. The responses of Sephadex G-10-passed (responder x nonresponder)F(1) spleen cells to TNP-(T,G)-A--L or TNP-(H,G)-A--L were reconstituted by spleen adherent cells from only responder strains. Spleen adherent cells from F(1) mice reconstituted the responses to both antigens. Spleen adherent cells from each of the strains tested reconstituted the non- Ir gene-controlled response to a third antigen, TNP-keyhole limpet hemocyanin. The inability of spleen adherent cells from nonresponder strains to reconstitute the responses to either TNP-(T,G)-A--L or TNP-(H,G)-A--L was not a result of active suppression induced by the presence of nonresponder adherent cells, since a mixture of responder and nonresponder spleen adherent cells reconstituted the responses to both antigens. The use of spleen adherent cells from recombinant strains demonstrated that the autosomal dominant genes controlling the ability of spleen adherent cells to function as accessory cells in the responses to TNP-(T,G)-A--L and TNP-(H,G)-A--L are located in the K or I-A regions of the responder H-2 complex, the same region(s) of H-2 as the Ir genes controlling overall in vitro and in vivo responsiveness to these antigens.

Animals↗