The occurrence of tumor immunity in mice bearing a growing plasmacytoma (PC) was studied by local adoptive transfer assay. Spleen cells from mice with a large PC but not with a nonpalpable or small PC retarded and often inhibited entirely the growth of homologous PC. They occasionally caused late regression of growing homologous and heterologous PC. The individual tumor-specific immune effector cells were found to be radiosensitive, non-adherent, Thy 1-positive T-cells. They were resistant to treatment of mice with high-dose cyclophosphamide (CTX). Their generation, however, was abrogated by low-dose CTX and irradiation at the early stage of their development. Spleen cells from PC-bearing mice treated with high-dose CTX were enhanced in their effector activity, suggesting the co-existence of CTX-sensitive suppressor cells. The suppressor cells could be demonstrated in spleens of mice bearing a heterologous PC and were found also to be radiosensitive, non-adherent, Thy 1-positive T-cells. Their generation was blocked by treatment of mice with CTX during the early stage of PC development. These findings provide evidence for the occurrence of immune effector T-cells in mice with a growing PC. This immunity appears to be down-regulated by CTX-sensitive suppressor cells.

Animals↗

PubMed1979

Fibreoptic injection of oesophageal varices.

A new technique for injecting sclerosant into oesophageal varices uses a flexible gastroscope. Once the gastroscope has been inserted a flexible tube with a window cut into its distal end is pushed down over the gastroscope until a varix protrudes through the window. The varix can then be injected with a needle passed down the biopsy channel of the gastroscope. Once the varices have all been injected in this way the tube is advanced to compress the injection sites and so help control bleeding. This method, using a flexible gastroscope, has proved easier and safer than the traditional method using a rigid gastroscope.

Esophageal and Gastric Varices↗

PubMedDate not supplied

NASBA technology: isothermal RNA amplification in qualitative and quantitative diagnostics.

Nucleic acid amplification technologies allow for the development of highly sensitive and specific diagnostic assays. The capacity to amplify and detect analyte targets, which may be present in a clinical sample as a single copy; is characteristic of many of these amplification technologies. NASBA is an isothermal method of nucleic acid amplification with such capability, and is particularly well suited for the amplification of RNA analytes. NASBA utilizes the coordinated activities of three enzymes (AMV-RT, RNase H, T7 RNA polymerase), and two oligonucleotide primers which are specific for the analyte target. The amplification process is part of a total system which includes a versatile nucleic acid isolation procedure, and powerful detection methodology. In this report, the development of NASBA technology for the detection of human Retrovirus RNA will be discussed. Specifically, a qualitative NASBA assay for the RNA of HTLV I, and a quantitative NASBA assay for HIV-1 will be described.

Acquired Immunodeficiency Syndrome↗