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J Wass

Publications and source records attributed to J Wass.

44 records · Page 3Linked to original sources
PubMed1982

Differential synchronization of leukemic cells in vivo by hydroxyurea.

Flow cytometry (FCM) was used to monitor the cell cycle changes which occurred in the bone marrow cells of a patient with acute myeloblastic leukemia following pre-induction treatment with hydroxyurea. Flow cytometric and cytogenetic analysis showed two populations of cells; one hypertetraploid and presumably leukemic, and the other diploid and possibly normal. Sequential FCM monitoring of bone marrow cells after hydroxyurea demonstrated an early rise (after 24 h) in the S-phase component of diploid cells and a rise in the S-phase component of hypertetraploid cells 48-72 h later. Conventional induction therapy timed to coincide with this latter peak resulted in early remission.

Cell Cycle↗
PubMed1981

Chemotactic factor-induced adherence of tumor cells.

Two peptides which have previously been shown to induce chemotactic motility in a number of tumor cells were tested for their ability to alter the adhesiveness of Walker Carcinosarcoma cells (A chemotactically-responsive rat tumor) and normal rat fibroblasts (which have previously been shown to be chemotactically nonresponsive). Adherence of the tumor cells to nylon fibers was increased in a dose-dependent manner by the two active peptides. Adherence of the fibroblasts was not increased. Nonchemotactic peptide analogues of the two active peptides did not alter the adherence of either cell type. The increased adhesiveness to foreign surfaces may contribute to the chemotactic response.

Animals↗
PubMed1981

The chemotactic response of tumor cells. A model for cancer metastasis.

Injection of a C5-derived chemotactic factor for tumor cells into the peritoneal cavities of Sprague-Dawley rats induced diffuse mesenteric metastasis following the intravenous injection of Walker carcinosarcoma cells. Intraperitoneal injections of culture medium, histamine, or of trypsin-treated albumin resulted in many fewer metastases. Intraperitoneal injections of the chemotactic factor, unlike histamine, did not alter mesenteric vasopermeability as measured by the exudation of Evans blue into the mesentery. In vitro, tumor cells responded to the chemotactic factor by demonstrating directed migration in the Boyden chamber, by volume changes, measurable in the Coulter counter, and by demonstrating an increased adherence to nylon fibers. These phenomena are similar to the behavior of neutrophils in the presence of their chemotactic factors. All the responses in vitro were markedly depressed by the addition of 2-deoxyglucose, while the cell swelling response was slightly enhanced by cytochalasin B (again similar to the responses of leukocytes). The data suggest that movement of tumor cells from the circulation may be under chemotactic influence in the manner similar to the responsiveness of neutrophils to leukotactic stimuli in vivo.

Animals↗
PubMed1980

Axonal transport of neuropeptides in the cervical vagus nerve of the rat.

Accumulations of the neuropeptides substance P (SP), somatostatin (ST), and vasoactive intestinal polypeptide (VIP) proximal to a crush in the cervical vagus nerve of the rat have been measured using sensitive radioimmunoassays. Each of the peptides was rapidly transport towards the peripheral terminals of vagal afferent fibres, with average rates of flow ranging from 0.8 to 2.7 mm h-1. In the rabbit vagus nerve, SP was transported with an average rate of 4 mm h-1, which is more than double the rate for this peptide in the rat. Double crush experiments in rabbit vagus nerves indicated that the rapidly transported proportion of the total content of SP in the nerve free was about 34%. From this, the rate of transport of SP in the rapidly transported pool in the rabbit vagus nerve can be calculated to be 12 mm h-1 (280 mm day-1). Since such double crush experiments were not possible in the rat, it is not clear whether the different average rates of transport of SP in the rat and the rabbit reflect real differences in the rate of rapid transport in the two species. In common with rapid axonal transport of other neurotransmitters, the transport of SP and ST in the rat vagus nerve was blocked by colchicine, a drug that disrupts microtubules.

Animals↗
PubMed1980

Standardization of flow microfluorometers using glutaraldehyde fixed lymphocytes.

The preparation of glutaraldehyde fixed lymphocytes as a reference standard in flow microfluorometry is described. The ease of preparation, the stability of the cells over time, their ability to stain reproducibly in the range expected of fresh human peripheral blood and bone marrow cells and, most importantly, the fact that they may be used to resolve optimally and situate correctly the G1 peak of normal mammalian cells, make them a reliable tool for the calibration of flow microfluorometers and for detection of aneuploid populations.

Fluorometry↗