Biomedical subjects

T Sun

Publications and source records attributed to T Sun.

255 records · Page 15Linked to original sources

PubMedDate not supplied

Intestinal microsporidiosis. Report of five cases.

Five cases of intestinal microsporidiosis are reported, including one case of a heterosexual female acquired immunodeficiency syndrome (AIDS) patient, three homosexual males, and one bisexual male AIDS patients with detailed description of their clinical course. These five cases underscore the severity of immunodeficiency in patients with microsporidiosis. All patients had multiple opportunistic infections and a CD4 cell count below 100/microliters long before diarrhea developed. This is the first kinetic study of helper T-lymphocytes in cases of microsporidiosis. Diagnosis was made by duodenal biopsies stained with Brown and Brenn or Gram-Weigert technique (confirmed by electron microscopy) and by stool smears stained with a modified trichrome technique. However, the best preparation was plastic sections stained with toluidine blue, which demonstrated both the spores and plasmodia clearly. In our evaluation, Giemsa stain was also acceptable for identification of microsporidian spores in both intestinal biopsies and stool smears, but there was a failure to identify the organism on hematoxylin and eosin, acid-fast, periodic acid-Schiff, and Gomeri's methenamine silver stained preparations. Therapeutic attempts using albendazole, metronidazole, octreotide, and zidovudine (AZT) failed to eradicate microsporidia in these patients.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

T-cell receptor expression in lymphoid neoplasms. A comparison of phenotypic expression and genotyping.

T-cell receptor antibodies (TCR alpha beta and TCR gamma delta) were used for a flow cytometric study of 114 specimens of lymphoid neoplasms and normal controls in order to find out whether or not the expression of TCR proteins differs in between normal and neoplastic tissues. It was found that TCR alpha beta population was predominant in all categories except T gamma lymphoproliferative disorder (TGLD), T-cell lymphoblastic leukemia (T-ALL), and natural killer-like T-cell lymphoma (NKTL), in which three of 18, one of three, and two of two specimens, respectively, showed a predominant TCR gamma delta population. Natural killer cell lymphoma (NKL) showed essentially absence of either TCR alpha beta or TCR gamma delta protein. Therefore, TCR antibodies can be selectively used in cases of TGLD, T-ALL, and NKTL to substantiate their diagnoses. Furthermore, the absence of TCR protein is characteristic of NKL and helps to distinguish it from NKTL. Without the TCR antibodies, TCR gene analysis is sometimes needed to separate these two entities. When comparing with genotyping, 11 of 12 cases with TCR beta gene rearrangement and one of two cases with TCR alpha gene rearrangement expressed TCR alpha beta protein. One of four cases with TCR gamma gene rearrangement and both cases with TCR delta gene rearrangement expressed TCR gamma delta protein. Thus, TCR antibody phenotyping can reliably predict TCR genotypes under most circumstances.

Diagnosis, Differential↗

PubMedDate not supplied

Immunization with interleukin-2-secreting allogeneic cells transfected with DNA from mouse melanoma cells induces immune responses that prolong the lives of mice with melanoma.

Altered genes in tumor cells specify tumor-associated antigens. Because genetic instability is a characteristic of the malignant cell phenotype, a large number of different, altered genes may be present in a population of neoplastic cells, specifying an array of undefined tumor-associated determinants. We hypothesized that immunogenic cells transfected with DNA from malignant cells will include cells that specify tumor-associated antigens. To test this question, we deliberately mutagenized a population of B16 melanoma cells (H-2b) by ultraviolet-B irradiation. DNA from the surviving cells was used to transfect LM cells (H-2k), a mouse fibroblast cell line modified previously to secrete interleukin-2. The transfected allogeneic cells were then tested for their immunogenic properties in C57BL/6J mice (H-2b) syngeneic with the melanoma. Mice injected with a mixture of the mutagenized B16 cells and the transfected cells survived significantly longer than untreated mice injected with the mutagenized B16 cells alone. Mice injected with a mixture of mutagenized B16 cells and cells transfected with DNA from unirradiated B16 cells died in shorter intervals. Based on the results of cytotoxicity assays performed in vitro, the cellular immune responses of greatest magnitude were directed toward the type of cell from which the DNA was obtained.

Animals↗