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Biomedical subjects

J Yates

Publications and source records attributed to J Yates.

At least 127 records · Page 7Linked to original sources
PubMed1982

Lack of correlation between transformed characteristics in culture and tumorigenicity of mouse mammary tumour cells.

Androgen responsive and unresponsive Shionogi 115 mouse mammary carcinoma cells have been examined for anchorage-independent growth and tumorigenicity in nude mice. The two cell types exhibit transformed and normal growth characteristics respectively, but both give rise to tumours in nude mice. No correlation between tumorigenicity and transformed characteristics including anchorage-independent growth could be demonstrated.

Animals↗
PubMed1982

Cytosine arabinoside with daunorubicin or adriamycin for therapy of acute myelocytic leukemia: a CALGB study.

A randomized comparison of the relative efficacy and toxicity of daunorubicin (DNR) at 30 or 45 mg/sq m or adriamycin (ADM) at 30 mg/sq m, given on the first 3 days of a 7-day continuous infusion of cytosine arabinoside (ara-C) at 100 mg/sq m/day, shows the outcome to be dependent on anthracycline, dose, and patient age. DNR 45 is significantly better than DNR 30 or ADM 30 for inducing complete remissions (CR) in patients younger than 60 yr, (72%, 59%, 58% CRs, respectively). DNR 30 is better than DNR 45 or ADM 30 for inducing CR in patients older than 60 yr (47%, 31%, 35%, respectively). There was a corresponding shift in the induction mortality for the age, dose, and anthracycline groups. Adriamycin was significantly more toxic to the gastrointestinal tract than daunorubicin. The duration of complete remission, with cyclic courses of maintenance therapy, was independent of the patient's age, the dose, or choice of anthracycline used in induction, and of whether the maintenance courses were given every 4 wk or every 8 wk.

Adolescent↗
PubMed1981

Capillary blood flow in the canine colon and other organs at normal and raised portal pressure.

Capillary blood flow in the canine colon and other organs has been assessed over a wide range of portal pressures using radio-labelled microspheres. The proximal colon received a greater proportionate flow than the distal region. At both normal and raised pressures, the mucosa received 90% of the total colonic capillary flow. A highly significant negative correlation (P less than 0.001) was found between colonic capillary blood flow and portal pressure. A highly significant positive correlation (P less than 0.001) was found between colonic capillary blood flow in the superior mesenteric artery.

Animals↗
PubMed1981

Changes in microfilament and focal adhesion distribution with loss of androgen responsiveness in cultured mammary tumor cells.

The actin-containing microfilaments, microtubules, and fibronectin expression of Shionogi 115 mouse mammary tumor cells were visualized by indirect immunofluorescence microscopy. Also studied was the focal adhesion distribution as revealed by interference reflection microscopy and the ability of the cells to grow in suspension culture. All these parameters were documented for androgen-responsive and -unresponsive cells grown in culture, as well as the transition of androgen-responsive to -unresponsive cells when deprived of androgen. The androgen-unresponsive cells had extensive and prominent microfilament bundles together with focal adhesions on the lower cell surface and also showed strict anchorage dependence for growth. In contrast, microfilament bundles and focal adhesions were absent from androgen-responsive cells, which furthermore had the ability to grow in suspension culture. Differences were also apparent in fibronectin expression, the androgen-unresponsive cells having more of this glycoprotein detectable on their surfaces than the androgen-responsive cells. The androgen-responsive and -unresponsive cells had similar microtubule arrays, however. During the transition from the androgen-responsive to the androgen-unresponsive phenotype, the androgen-responsive cells gradually took on the characteristics of androgen-unresponsive cells as judged by cellular morphology or the presence of focal adhesions and microfilament bundles. At intermediate stages in this process, characteristics of both cell types were visible in the cell populations. However, at the stage where all androgen-responsive characteristics were lost, the cells were no longer androgen sensitive. The loss of androgen responsiveness in Shionogi 115 mouse mammary tumor cells is correlated with changes at the cell membrane and the microfilament component of the cytoskeleton.

Animals↗
PubMed1981

Correlation of growth properties and morphology with hormone responsiveness of mammary tumor cells in culture.

A cell line derived from the androgen-responsive Shionogi 115 mouse mammary carcinoma is being used to investigate the changes in cell function accompanying steroid removal from steroid-responsive breast tumor cells. Shiongi 115 mouse mammary carcinoma cells become androgen unresponsive after two weeks of culture in the absence of testosterone although androgen receptors are still present in the cytoplasm and nucleus. Androgen-responsive cells are fibroblastic in appearance, have a low serum requirement, and can proliferate in suspension culture. Unresponsive cells, however, show a flattened morphology, are serum sensitive, and are anchorage dependent. As the androgen receptor mechanism of the unresponsive cells is intact, loss of sensitivity may be caused by a postreceptor defect. To determine the nature of this defect, the temporal relationships of changes in hormone responsiveness, morphology, serum sensitivity, and growth properties have been examined over a period of seven weeks following removal of testosterone from Shionogi 115 mouse mammary carcinoma cell cultures. Responses to testosterone and anchorage independence are both lost over a period of one to two weeks while serum sensitivity increases more slowly during the same period. The most rapid and least reversible change is seen in morphology. It is suggested that hormone responsiveness is related to properties of the cytoskeleton and cell membrane which influence growth rates and multiple sensitivities of tumor cells.

Animals↗
PubMed1979

An exploration of cancer staff attitudes and values.

A multidisciplinary team involved in the care of patients with advanced cancer including physicians, nurses, social workers, physical therapists, nutritionists, clergymen, enterostomal therapists, biostatisticians and administrative personnel were studied over a period of eighteen months. A prospective study of staff attitudes and values about life, disease, and medical care which focused particularly on cancer, cancer treatment and patients with cancer was undertaken. Data were gathered from the staff by written responses to the following instruments: 1) Rokeach Value Survey and 2) a Personal Attitudes Toward Illness Questionnaire. This longitudinal prospective study demonstrated the reliability of scrutinizing individual and collective staff characteristics in a cancer care team. Although most team members had minimal previous contact with clinical research or with patients with advanced cancer, increased exposure did not result in changes in staff attitudes and values over the period of seventeen months.

Attitude of Health Personnel↗
PubMed1979

Neurolepticlike actions of l-methadone: effect on mescaline-induced altered behavior and on tissue levels of mescaline in mice.

Mice were injected ip with either saline, l-methadone (2.5, 5, 20 mg/kg), perphenazine (1, 10, 15 mg/kg), or chlorprothixene (1.25, 2.5, 15 mg/kg) 30 min prior to mescaline-14C (25 mg/kg). Mescaline-induced behavioral changes such as agitation, excitement, slight increase in ventilation, and fright to sound stimuli were prevented by all doses of three drugs, and head-shaking, scratching, and locomotor-increasing effects by 5 and 20 mg/kg methadone and by all doses of both neuroleptics. Catalepticlike state and moderate to marked hypothermia induced by all doses of chlorprothixene, 10 and 15 mg/kg perphenazine, and 20 mg/kg methadone were not reversed by mescaline. Chlorprothixene (all doses), perphenazine (10, 15 mg/kg), and methadone (5, 20 mg/kg) caused marked retention of mescaline and its deaminated metabolite, 3, 4, 5-trimethoxyphenyl acetic acid in both brain and plasma. The fact that relatively higher doses of methadone than neuroleptics are needed to ensure effective antagonism to mescaline action tends to indicate a less specific interaction of the opiate with the neuroleptic/dopamine receptor proposed for central mescaline effects.

Animals↗
PubMed1978

Cholinergic agents inhibit sodium transport across the isolated toad bladder.

Acetylcholine and carbamylcholine (carbachol) inhibited sodium transport across the toad bladder. This effect was blocked by atropine. Carbachol increased the uptake of 45Ca by isolated toad bladder epithelial cells. This increased 45Ca uptake was blocked by atropine, pentobarbital, or lanthanum chloride. The inhibitory effect of cholinergic agents on sodium transport was dependent on external calcium concentration and was abolished by decreasing external calcium from 2 to 0.2 mM or by agents (pentobarbital, lanthanum chloride) which prevent the movement of calcium into cells. Carbachol increased modestly, but significantly, the levels of cyclic GMP in isolated toad bladder epithelial cells. This effect was blocked by atropine. Whether the decrease in sodium transport produced by cholinergic agents is the result of increased intracytoplasmic calcium levels, increased cyclic GMP levels, or a combination of both remains to be established.

Acetylcholine↗
PubMed1978

Multiple sensitivities of mammary tumor cells in culture.

Cloned cell lines derived from the androgen-responsive Shionogi 115 mouse mammary carcinoma, when cultured in the presence of 3.5 X 10(-8) M testosterone, retain their responsiveness to testosterone and 5alpha-dihydrotestosterone and exhibit fibroblast-like morphology; their growth is poorly regulated by cell density. Dexamethasone at 10(-8) M inhibits proliferation of these cells by 30% but stimulates them by 235% at 10(-6) M in the temporary absence of testosterone. Cell growth is little affected by serum concentration. When cultured for 3 to 4 weeks in testosterone-free medium, however, the cells lose their androgen responsiveness and retain the inhibitory but not the stimulatory response to dexamethasone. They also show an increased sensitivity to serum and increased density regulation and change to an epithelial morphology. It is suggested that the loss of sensitivity to androgens, which does not result from absence of androgen receptor, is related in a complex way to the increased sensitivities to serum and density regulation.

Animals↗
PubMed1976

Effect of imidazole on renal gluconeogenesis.

The metabolic effects of imidazole were tested in rat renal cortex. Imidazole enhanced the activity of renal cortical phosphodiesterase in vitro. Imidazole inhibited glucose production in a dose-dependent fashion from a variety of substrates in the gluconeogenic pathway proximal to the triose phsophates. The stimulation in renal gluconeogenesis resulting from isoproterenol and parathyroid hormone was inhibited by imidazole. These changes correlated with an inhibition of the augmented levels of renal cortical cyclic AMP levels produced by these hormones. These studies indicate that imidazole is an effective activator of phosphodiesterase in intact renal cells and lend further support to the suggestion that the stimulation of renal gluconeogenesis produced by isoproterenol and parathyroid hormone is mediated by a release of cyclic AMP.

3',5'-Cyclic-AMP Phosphodiesterases↗