Evidence for bimodal distribution of breast carcinoma ER and PgR values quantitated by enzyme immunoassay.

Breast carcinoma oestrogen receptor (ER) and progesterone receptor (PgR) values obtained by radioligand binding assays have commonly been observed to have approximate log-normal distributions. We examined the distribution of log-transformed receptor values obtained by enzyme immunoassay for 5468 primary breast carcinomas in five Ontario laboratories. In each laboratory, it was found that the frequency histograms for the log transformed receptor values were not unimodal, and generally were suggestive of bimodality.

Amino acid transport in multidrug-resistant Chinese hamster ovary cells.

In the process of assessing the effect of anthracycline drugs on cellular membrane function in cultured multidrug resistant (MDR) and its parental cells, experiments were undertaken to investigate the kinetics of neutral amino acid membrane transport (the sodium dependent A and ASC systems). P-glycoprotein, a high molecular weight energy requiring integral membrane protein responsible for actively pumping drugs out of cells, has been shown to be overexpressed in MDR cells. It was our hypothesis that its presence might affect other membrane energy requiring systems such as amino acid transport.

Amino and iodotamoxifens: synthesis, estrogen receptor affinity and biodistribution.

Both geometrical isomers (E and Z) of an aminotamoxifen (2) have been prepared as precursors of the corresponding E and Z iodotamoxifens (1). The ability of E and Z-1 and 2 to compete with [3H]estradiol for estrogen receptors in rat uterine cytosol was measured relative to Z-tamoxifen and estradiol. The four tamoxifen derivatives showed affinities ranging from 50% to 1600% of that of tamoxifen.

Changes in cyclic nucleotide profiles in proliferating multi-cell spheroids.

The intracellular concentration of cyclic adenosine 3':5'-mono-phosphate (cAMP) has been shown to be related to each developmental phase of the cell cycle. Highest levels of this nucleotide are evident during the S-phase (the DNA synthetic phase) which has also been shown to be radiation-sensitive. The relationship between the levels of cyclic nucleotides, cAMP and guanosine 3':5'-monophosphate (cGMP), and the proliferation of cells in a tumor model system was investigated using V79-171b Chinese hamster lung cells grown both as monolayer and as three dimensional cell clusters (spheroids).

Role of phospholipid fatty acids on the kinetics of high and low affinity sites of cytochrome c oxidase.

The nature of the interactions between cytochrome c oxidase and the phospholipids in mitochondrial membranes has been investigated by varying the nature of the fatty acyl components of Saccharomyces cerevisiae. A double fatty acid yeast mutant, FAI-4C, grown in combinations of unsaturated (oleic, linoleic, linolenic, and eicosenoic) and saturated (lauric and palmitic) fatty acids, was employed to modify mitochondrial membranes. The supplemented fatty acids constituted a unique combination of different acyl chain lengths with varying degrees of unsaturation which were subsequently incorporated into mitochondrial phospholipids.

CA 125 surveillance and second-look laparotomy in ovarian carcinoma.

CA 125 was evaluated as a tumor marker in 31 patients undergoing treatment for ovarian carcinoma, 17 of whom had second-look laparotomies. At the time of second-look laparotomy, 14 patients had CA 125 values in the normal range. Six of these patients had a positive second-look laparotomy.

Membrane glycoprotein and surface free energy changes in hypoxic fibroblast cells.

Hypoxia affects the biochemistry of mammalian cells and thus alters their sensitivity to subsequent chemo- and radiotherapy. When V79 Chinese hamster lung fibroblasts were grown under conditions of extreme hypoxia (less than 10 ppm O2) there was a significant shift in the membrane glycoprotein composition. Scanning electron microscopy revealed altered cell surface morphology including loss of pseudopodial projections.

Changes in ultrastructure and function of hypoxic V79 fibroblast cells after treatment with misonidazole.

Morphologic and enzymatic changes due to exposure to the radiosensitizing chemical, misonidazole, have been identified in V79 cells grown in a system in which oxygen tensions and culture density have been controlled. Misonidazole prevented the increase in mitochondrial size normally seen during exposure of these cells to conditions of moderate hypoxia (2 X 10(3) ppm O2). Mitochondrial size was also significantly decreased in cells from exponential cultures exposed to 1 mmol/l misonidazole.

Inter-laboratory quality control of estrogen and progesterone receptor assays in breast cancer tissue using lyophilised cytosols.

In 1981 a quality control (QC) program for estrogen and progesterone receptor assays was organized among six laboratories in Ontario, Canada. Twenty-three vials of lyophilised cytosol prepared from human breast tumor tissues were analysed by each laboratory over a two-year period. Samples of each batch of QC material were analysed at least twice: either in the same batch or on separate occasions.

Saccharomyces cerevisiae as a model eukaryote for studies on mitochondriogenesis.

A great deal of progress has been made in elucidating the underlying mechanisms which control the interplay between the nuclear and mitochondrial genomes during biogenesis of mitochondria. The advantage of using the yeast Saccharomyces cerevisiae in these studies over other eukaryotic cells will be discussed.

Ultrastructural changes in V79 hamster lung fibroblasts during hypoxic exposure.

Cells in tumors that are deprived of their blood supply become hypoxic. These stressed cells adapt to their new environments by altering their metabolic regimen which in time induces cellular structure changes. The morphologic make-up of these O2-deprived cells is the focal point of this electron microscopy study.

Iodination of [Tyr8]-bradykinin-comparison of chloramine-T and lactoperoxidase techniques.

Antigen-antibody kinetics were studied using a hapten which was iodinated by two unique procedures. Using bradykinin, a vasopressor hormone as a model peptide, radioactive iodination (125I) of its 8-tyrosyl analogue was carried out both enzymatically and chemically using modified procedures. Two distinct chemical species were obtained which were characterized on a chromatographic, chemical as well as charge basis as a mono-iodinated form of [Tyr8]-bradykinin using the lactoperoxidase procedure and a di-iodinated entity using chloramine-T technique.

In situ oxygen consumption rates of cells in V-79 multicellular spheroids during growth.

The rate of consumption of oxygen by V-79 cells in multicellular spheroids was measured as a function of the spheroid diameter. In situ consumption was equal to that of exponentially growing cells for spheroids less than 200 micron in diameter. The rate of oxygen consumption decreased for cells in spheroids between 200 and 400 micron diameter to a value one-fourth the initial, then remained constant with further spheroid growth.

Immunological and biological activities of fragments and analogs of bradykinin.

Using a number of analogs and fragments of a short-chain peptide bradykinin, a series of experiments have been carried out to assess the effect of modifications to the basic structure of the parent molecule on its myotropic and immunoreactive properties. Binding kinetics of both an antibody raised against the authentic nonapeptide and its specific biological receptor found in the guinea pig ileum were used to study these alteration effects. Peptide derivatives of bradykinin with an extension at the N-terminal (Lys- and Met-Lys-bradykinin) cross-react with the antibody raised to bradykinin 59 and 70% respectively.

Effect of radiosensitizing agents on electron transport systems.

Experiments have been carried out to study the interaxtion between chemical radiosensitizing agents and model electron transport systems. Using an NAD(P)H:O2 oxidoreductase enzyme as such a model, it was demonstrated that radiosensitizers can act as intermediates in the transfer of electrons from NADH to O2, even in the presence of classical inhibitors of electron transport, with anefficiency related to both their redox potentials and their radiosensitizing abilities. This work which was further confirmed in mammalian mitochondria and microsomes as well as in a cultured cell system indicated that these sensitizers can accept electrons from a variety of organelle systems.

Hypergastrinemia and gastric acid hypersecretion in uremia.

Twenty-one chronic hemodialysis patients were investigated. While only two had radiologic evidence of peptic ulceration, three had markedly elevated basal acid outputs, thirteen had significantly elevated maximal acid outputs and seven had fasting duodenogastric reflux. Elevated fasting serum gastrin levels and prolonged gastrin circulation following stimulated endogenous release were also demonstrated.

Assembly of complex III into newly developing mitochondrial membranes.

Yeast cells grown anaerobically in 0.02% linoleic acid were transferred to air in the presence of 0.02% elaidic acid.

Aerobic adaptation in yeast. III. Changes in metabolic intermediates during anaerobic-aerobic transitions in exponentially growing cultures.

The changes in mechanism of control and in the mode of metabolism which yeast cells undergo when an anaerobic-aerobic transition is imposed on them has received much attention. One experimental approach to this type of investigation has been a step-down transition. The data from our experiments (cf.

Aerobic adaptation in yeast. I. Changes in metabolic intermediates during a step-down anaerobic-aerobic transfer.

Early investigation into the mechanism of mitochondriogenesis in the facultative anaerobe Saccharomyces cerevisiae used anaerobic-aerobic transitions as model systems to study the in vivo assembly of these oxidative organelles. This methodology has become entrenched in the early literature and as a result a definitive study has been undertaken utilizing this protocol (high hexose, complete medium under anaerobic growth transferred to low hexose, minimal medium with aerobic environment) to study the altered distribution of various metabolites during these transitions. Measurement of all the glycolytic, and some tricarboxylic acid intermediates during such a transition has elucidated the following points.

Aerobic adaptation in yeast, IV. Alterations in enzyme synthesis during anaerobic-aerobic transitions in exponentially growing cultures.

As a corollary to the metabolite data obtained from yeast cultures undergoing an exponential anaerobic-aerobic phase transition, levels of various glycolytic and citric acid cycle enzyme activities have been monitored in these cells. The relation of the changes in these enzyme activities in cells grown on either glucose or galactose is discussed on light of different metabolic postures these cells demonstrate as a result of their transitions. A general discussion is presented which compares the results obtained in this series of papers from both step-down and exponential transfer experiments and relates these data to control of mitochondriogenesis in yeast.

Aerobic adaptation in yeast. II. Changes in enzyme profiles during a step-down anaerobic-aerobic transfer.

The levels of various enzymes and components of the glycolytic and respiratory pathways of the yeast Saccharomyces cerevisiae have been determined during a step-down, anaerobic-to-aerobic transition. These activities were determined as an adjunct to the respective metabolite data reported in the first paper in this series. It is clear from the data that anaerobic conditions induce an environment conducive to express glycolytic enzyme activities, while manifesting a differential induction/repression effect on oxidative enzymes.

The biogenesis of mitochondrial membranes in the yeast Saccharomyces cerevisiae.

Membrane lipids of yeast mitochondria have been enriched by growing yeast cells in minimal medium supplemented with specific unsaturated fatty acids as the sole lipid supplement. Using the activity of marker enzymes for the outer (kynurenine hydroxylase) and inner (cytochrome c oxidase and oligomycin-sensitive ATPase) mitochondrial membranes, Arrhenius plots have been constructed using both promitochondria and mitochondria obtained from O2-adapting cells in the presence of a second unsaturated fatty acid (i.e.