Thrombin-sensitive surface protein of cultured chick embryo cells.
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Animals↗
Biomedical subjects
N N Teng
Publications and source records attributed to N N Teng.
Appearance of acetylcholine receptors in cultured myoblasts prior to fusion.
The development of the acetylcholine receptors in chick embryo myoblasts from 11-day old embryos was studied in vitro. Using the purified alpha-bungarotoxin labeled with radioactive iodide, a high concentration of acetylcholine receptors was found in the prefusing myoblasts; most of these receptors were located in the interior of the myoblasts. However, upon the completion of myoblasts fusion, the majority of the acetylcholine receptors appeared on the external cell surface of the myotubes.
Acetylcholine↗
Mitogenicity of thrombin and surface alterations on mouse splenocytes.
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Animals↗
The role of surface proteins in cell proliferation as studied with thrombin and other proteases.
This communication explores the capacity of different proteases to stimulate DNA synthesis in resting chick embryo fibroblasts and to cause the removal of cell membrane proteins previosly postulated as important in the regulation of growth and division of cells. Thrombin, a highly specific protease and a known mitogen, was incubated with chick embryo fibroblasts, and analysis was made of the cell membrane proteins. Of particular interest were a protein of molecular weight 250,000, which is known to be readily removed by the action of trypsin and is not present in most transformed cells, and two other proteins, which are reduced in amount in transformed as compared to confluent resting cell cultures. None of these three proteins was removed by thrombin when the latter was added to confluent cells in concentrations sufficient to cause significant increase in DNA synthesis twelve hours after stimulation by the protease. The presence or absence of these proteins in the membranes of confluent resting or transformed cells of chick embryo fibroblasts does not seem to be directly related to the process of regulation of DNA synthesis and cellular division.
Animals↗
The role of laparoscopy in the management of gynecologic malignancy.
With the advent of minimally invasive laparoscopic techniques, most gynecologic procedures for benign conditions can be performed in an outpatient setting. However, the role of such techniques in gynecologic oncology is not well defined. By reviewing the literature and presenting some new data, we attempt to elucidate the applications of operative videolaparoscopy in gynecologic oncology. Advanced laparoscopic techniques are utilized for the management of cervical cancer as well as the staging and treatment of endometrial and ovarian cancers. Such techniques are used in performing radical hysterectomy for early stage cervical cancer, pelvic and paraaortic lymphadenectomy, and second look laparoscopy following chemotherapy for ovarian cancer. Even though preliminary data are encouraging, large prospective controlled studies with long-term follow-up are necessary to better define the role and limitations of laparoscopy in the treatment of gynecologic malignancies.
Female↗
Susceptibility of B-cell lymphoma to human antibodies encoded by the V4-34 gene.
Our previous studies have shown that mAbs derived from the human V4-34 gene bind and kill human B-lymphocytes via membrane disruption. This study demonstrates the cytotoxicity of two V4-34 encoded mAbs, 216 and Z2D2, towards human B-cell lymphoma. In vitro, 216 and Z2D2 are cytotoxic to a variety of B-cell lymphomas obtained from patient biopsies. In vivo, increased survival was observed with both mAbs in a lymphoma model developed in scid mice with human B-cell line Nalm-6. Studies in mice show that these mAbs are well tolerated with minimum side effects. Since 216 and Z2D2 show increased toxicity towards cycling cells, V4-34 mAb-based therapy can be additive with drugs that block cell-cycle progression. Stem cells that are V4-34 mAb ligand negative would not be depleted. Together, these studies recommend an evaluation of the two completely human mAbs in a phase I trial for B-cell lymphoma.
Animals↗
Synthesis and characterization of gentiobiose heptaacetate conjugate vaccines that produce endotoxin-neutralizing antibodies.
We have prepared aminoethyl (AE), aminopropyl (AP), and aminopentyl (APT) derivatives of gentiobiose heptaacetate (GH). These spacer compounds (AEGH, APGH, APTGH) have been coupled to succinylated diphtheria toxoid (Suc.DT) to produce conjugate vaccines. These conjugates all bind to the anti-lipid A human monoclonal antibody A6(H4C5) in an ELISA binding assay. Rabbits immunized with the APGH conjugate vaccine in either Freund's complete adjuvant or aluminum hydroxide gel produced antibody levels of 5120 and 3600 ELISA units, respectively, compared to an antibody level of less than 20 ELISA units for the prebleed sera. Sera from mice immunized with either the aminopropyl or the aminopentyl conjugate had antibody levels of 5120 and 2560 ELISA antibody units, respectively. These antibodies neutralized endotoxin in a Limulus lysate neutralization assay. Protection against the local Shwartzman reaction was demonstrated (p less than 0.05) in eight out of nine rabbits immunized with the Suc-DT-APGH conjugate vaccine compared to three out of 10 rabbits immunized with the carrier protein Suc-DT. Passive transfer experiments demonstrated that four out of five rabbits receiving immune serum were protected from Shwartzman reaction compared to one out of five rabbits receiving normal serum (p less than 0.1). These results indicated that epitopes contained in gentiobiose heptaacetate when properly presented as conjugate vaccines were capable of inducing neutralizing antibodies against endotoxin.
Amines↗