Effects of cell concentration on viability and metabolic activity during cryopreservation.

Increasing the cell concentration during the cryopreservation of red blood cells (RBC) increased hemolysis. Similarly, increasing the cell concentration during the cryopreservation of hepatocytes reduced both the viability of the cells as assessed by trypan blue exclusion and the metabolic activity of the trypan blue-excluding cells. In both cell types, significant damage appeared at cell concentration levels exceeding 60%.

Cryopreservation of isolated rat hepatocytes: effects of iron-mediated oxidative stress of metabolic activity.

In an attempt to quantitatively evaluate the destructive effects of free radicals on metabolism, freshly prepared and cryopreserved isolated rat hepatocytes were exposed to and incubated with Fe2+ compounds, reputedly inducing oxygen-derived free radicals (OFR) capable of attacking the lipid structures of cellular membranes. Malondialdehyde (MDA) formation was interpreted as an expression of free radical interaction with polyunsaturated lipids, and in vitro incubations were carried out during the period of constant MDA formation. Protein synthesizing activity was evaluated by incubating control hepatocytes and cells previously exposed to 100 microM of Fe2+, to 100 microM of Fe2+, and 100 microM of desferrioxamine and to 100 microM of desferrioxamine alone with 0.

Osmotic effects of dilution on erythrocytes after freezing and thawing in glycerol-containing buffer.

Red blood cells frozen in 1.7 M and particularly in 2.2 M of glycerol retain a high degree of integrity upon thawing as long as the dilution procedure of the cryoprotectant is slow and preferentially compensated by the addition of sorbitol.

Metabolic activity of freshly prepared and cryopreserved hepatocytes in monolayer culture.

The successful use of isolated hepatocytes for transplantation will, no doubt, require cryopreservation of the cells. However, cryopreservation results in the loss of viability of isolated hepatocytes. In this study a method is described that allows recovery of viable hepatocytes after cryopreservation.

Effects of sodium ascorbate (vitamin C) and 2-methyl-1,4-naphthoquinone (vitamin K3) treatment on human tumor cell growth in vitro. II. Synergism with combined chemotherapy action.

The growth inhibitory effects of a combined application of sodium ascorbate (Vitamin C) and 2-methyl-1,4-naphthoquinone (Vitamin K3) together with various chemotherapeutic agents has been examined on in vitro cultured human endometrial adenocarcinoma (AN3CA) cells. Combined vitamin treatment and chemotherapy in well defined conditions of cell confluence and at the dose levels applied result in a synergistic effect on growth inhibition. The combined vitamins when reaching their own synergistic cytotoxicity levels frequently obscure the additional synergistic effects attributable to the chemotherapeutic agents.

The effects of cryopreservation on protein synthesis and membrane transport in isolated rat liver mitochondria.

Protein synthesizing activity and membrane transport were examined in fresh and cryopreserved isolated rat liver mitochondria. In the presence of 0.6, 1.

The effects of cryopreservation on membrane integrity, membrane transport, and protein synthesis in rat hepatocytes.

The cryopreservation of hepatocytes is of particular interest as a step in the possible treatment of some inborn disorders of metabolism. This study examines the metabolic damage that occurs as a result of the freeze-thaw procedures and during subsequent incubation periods of isolated rat hepatocytes. Even for freshly prepared hepatocytes, the presence of 1.

The bioenergetics of mitochondria after cryopreservation.

The functional characteristics of rat liver mitochondria after cryopreservation with and without the addition of the cryoprotectant dimethyl sulfoxide (Me2SO) were evaluated. As criteria of functional integrity, polarographic measurements of substrate-linked oxygen consumption and luminescent assay of adenosine triphosphate (ATP) synthesis were considered before and after cryopreservation. The results demonstrated that mitochondrial damage after freezing was indicated by the polarographic studies but was not evident when ATP synthesis was considered.

Effects of pulsed electromagnetic fields on rat skin metabolism.

In an attempt to approach the mechanism of action of pulsed electromagnetic fields (PEMF) on biological systems, the effects on protein synthesizing activity and on membrane transport have been examined in rat skin. PEMF characterized by specific physical parameters stimulate the incorporation of L-[U-14C]isoleucine into the proteins of rat skin as well as the alpha-amino[1-14C]isobutyric acid uptake during incubation in buffer medium with extracellular electrolyte composition. Analogous incubation experiments carried out in an intracellular medium results in an inhibitory effect of PEMF on both biological functions.

Effects of sodium ascorbate (vitamin C) and 2-methyl-1,4-naphthoquinone (vitamin K3) treatment on human tumor cell growth in vitro. I. Synergism of combined vitamin C and K3 action.

The effects of sodium ascorbate (vitamin C) and 2-methyl-1,4-naphthoquinone (vitamin K3) administered separately or in combination on the in vitro cultured human neoplastic cell lines MCF-7 (breast carcinoma), KB (oral epidermoid carcinoma), and AN3-CA (endometrial adenocarcinoma) have been examined. When given separately, vitamin C or K3 had a growth inhibiting action only at high concentrations (5.10(3) mumol/1 and 10(5) nmol/l, respectively).

Cytotoxic effects of müllerian inhibiting substance (MIS)?

To determine whether Müllerian Inhibiting Substance (MIS) is the factor responsible for the cytotoxic effects of testicular preparations on gynecological cancers, homogenates of bovine fetal testes were fractionated by Sephadex G 200 chromatography and their cytotoxic effects tested on a Müllerian-derived endometrial cancer cell line (AN3-CA), an ovarian carcinoma cell line (CAOV 3) and on a breast cancer cell line (MCF 7). No difference in cytotoxicity was found between Müllerian and non-Müllerian derived human cancer cells. Cytotoxicity and MIS activity were found in different fractions on Sephadex G 200 gel chromatography.

Influence of practice on the biochemical analysis of steroid receptors in human breast cancer.

The value of experience and practice in the routine biochemical analysis of steroid receptors was studied in 2576 different primary breast cancer specimens over five consecutive years. The positivity rate (beyond 3 fm/protein) and the measured concentrations of the steroid receptors increase. The positivity rate and average steroid receptor concentration of the samples immediately frozen is significantly higher compared to the overall sample population.

Preservation of taenia coli by freezing and storage at -196 degrees C.

Some damaging effects that occur during cryopreservation by freezing to -196 degrees C have been evaluated in rabbit taenia coli by analyzing the proportional recovery of acetylcholine- and histamine-induced maximal contractions. Dimethyl sulfoxide (Me2SO) 10 v/v% was used as the cryoprotectant; it reversibly abolishes spontaneous contractility even after incubation at 37 degrees C during 2 hr. Programmed freezing at 0.

Ca2+ transport and permeability in inside-out red cell membrane vesicles after freezing.

To evaluate the effects of freezing and thawing on Ca2+ transport and permeability, inside-out red cell membrane vesicles (IORCMV) are examined. Exposure to the cryoprotectant Me2SO as well as different cooling regimes on unprotected and cryoprotected vesicles do not affect the membrane Ca2+ transport. However, freezing and thawing increase the membrane permeability to sucrose.

Biochemical and histochemical analysis of steroid hormone binding sites in human primary breast cancer.

Mammary carcinoma tissue from 514 primary breast cancer patients were all biochemically and histochemically analyzed for both estrogen receptors and progesterone receptors. The dextran-coated charcoal (DCC) method measured the ER and PR as defined by Scatchard analysis, ligand competition experiments and target organ specificity. The ligands, estradiol-6-carboxymethyloxime-BSA-fluoresceine isothiocyanate and hydroxyprogesteronehemisuccinate-BSA-tetramethylrhodamine isothiocyanate, used for histochemistry, did not bind to either ER or PR and were mainly bound to the membrane fraction of isolated breast cancer cells.

Interaction of ionizing irradiation with steroid receptors in human breast cancer cells.

Human mammary tumor cells in continuous culture (MCF-7 cells) are hormone- and radiosensitive. The interaction of both factors is analyzed. Ionizing irradiation lowers the concentration of both the estradiol and progesterone receptors per cell.

The interaction between different phorbol derivatives and cortisol.

Phorbol derivatives (phorbol-12,13-diacetate, phorbol-12,13-dibenzoate, phorbol-12,13-dibutyrate, and phorbol-12-myristate-13-acetate) interact with cortisol on a molecular basis. These molecular interactions are demonstrated via dexamethasone receptor assays and by changes in spectrophotometric characteristics when equimolar solutions of these phorbol compounds together with cortisol are compared to those of the pure solutions. The phorbol compounds characterized by modifications in the molecular ring structure and by substitution at position C20, lose the capacity to bind cortisol.

Effects of daily anti-estrogen treatment on uterine growth and progesterone receptor concentrations in adult rat uterus.

The effects of daily Tamoxifen treatment on adult rat uterus weight depend on the degree of estrogenic impregnation of the animal. In intact animals, Tamoxifen caused a decrease of the uterine weight. A weight increase was observed, after castration, which was dose-dependent without reaching saturation even with 500 micrograms of Tamoxifen per day.

Erythrocyte swelling after rapid dilution of cryoprotectants and its prevention.

These in vitro studies on canine red blood cells confirm that cell swelling occurs after rapid dilution of Me2SO and glycerol. Cells loaded with a penetrating cryoprotectant in a medium with low Na+, high K+ composition present significantly less swelling after rapid dilution of the cryoprotectant than cells exposed to an electrolyte medium characterized by high Na+, low K+ composition. The osmotic cell stress during rapid dilution of Me2SO can be completely counteracted by the simultaneous use of the nonpenetrating sorbitol during exposure and loading.

Independent regulation of growth and steroid receptors in uterus and mammary tumors of rats.

Anti-estrogens and progestagens are synergistically active in the treatment of hormone dependent tumors. The combined action of both compounds in daily treatment schedules are analyzed in rat uterus and in DMBA- induced rat mammary tumors. Tamoxifen in contrast to estradiol does not significantly affect tissue growth, while PgR induction is considerably stimulated by Tamoxifen.

The effects of ionizing irradiation on the sedimentation coefficient of cytoplasmic steroid receptors in rat mammary tumors.

The effects of ionizing irradiation on the sedimentation coefficients of both estrogen receptor (ER) and progesterone receptor (PgR) have been examined in comparison to the effects of proteolysis. DMBA-induced rat mammary tumors were subjected to a treatment of 20 Gy and the ER and PgR concentrations were determined at different time intervals after irradiation. On a 5-20% sucrose gradient the ER sedimented as 9-11 and 4-5 S molecular forms, while PgR sedimented as a small 8-9 S peak and a major 4-5 S peak.

The effects of different concentrations of glycerol and dimethylsulfoxide on the metabolic activities of kidney slices.

Kidney slices either were exposed to the cryoprotectants for 1 hr at room temperature and subsequently washed and incubated in fresh KR buffer containing only the radioactive metabolic tracers, or were immediately incubated for 2 hr at 37 degrees C in KR buffer containing the cryoprotectant and the tracers. Exposure to glycerol by incubation of kidney slices in Krebs-Ringer bicarbonate buffer containing varying concentrations of glycerol from 0 to 70% (v/v) resulted in a pronounced inhibitory effect on the protein synthesizing activity, while thymidine incorporation into DNA and the alpha-aminoisobutyric acid uptake through the cell membranes were less affected. Exposure of the tissue to buffer containing dimethylsulfoxide (Me2SO) in concentrations of 10 to 20% (v/v) resulted in a stimulatory effect on metabolism.

Effects of cortisol on tRNA methylase activities in rat mammary carcinoma.

Mammary carcinomas induced in rats by DMBA were divided into three types: I, hard proliferating tumors; II, tumors presenting from an early stage the first signs of cystic degeneration; III, lactating tumors. In all three types, cortisol reduced the protein content by 26%-30%. The already high tRNA methyltransferase activity in type I increased by 200% after cortisol treatment.

The effects of electric currents on ATP generation, protein synthesis, and membrane transport of rat skin.

Direct electric currents ranging from 10 microA to 1000 microA increase ATP concentrations in the tissue and stimulate amino acid incorporation into the proteins of rat skin. The amino acid transport through the cell membrane, followed by the alpha-aminoisobutyric acid uptake, is stimulated between 100 microA and 750 microA. The stimulatory effects on ATP production and on amino acid transport, apparently mediated by different mechanisms, contribute to the final increased protein synthesizing activity.