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Biomedical subjects

F Rosen

Publications and source records attributed to F Rosen.

At least 55 records · Page 3Linked to original sources
PubMed1979

Successful bone marrow transplantation in sensitized recipients.

Fourteen patients with aplastic anemia and one with the Wiskott-Aldrich syndrome who were specifically sensitized against their donors were successfully engrafted with bone marrow from those donors. Sensitivity was detected in antibody-independent and antibody-dependent cell-mediated lysis assays. In order to erase this immunity to non-MHR familial transplantation antigens, multiagent immunosuppression with cyclophosphamide, procarbazine, and whole rabbit antithymocyte serum (ATS) was used. The data suggest that ATS was largely responsible for abrogation of this sensitivity and indicate that immunity does not represent a barrier to successful transplantation.

Anemia, Aplastic↗
PubMed1978

Comparison of the antitumor activity and toxicity of 2,4-diamino-5-(1-adamantyl)-6-methylpyrimidine and 2,4-diamino-5-(1-adamantyl)-6-ethylpyrimidine.

The effects of two new compounds, 2,4-diamino-5-(1-adamantyl)-6-methylpyrimidine (DAMP) and 2,4-diamino-5-(1-adamantyl)-6-ethylpyrimidine (DAEP), on the growth of Walker carcinoma 256 were studied. In Sprague-Dawley rats, both compounds inhibited the growth of the Walker tumor, which is naturally resistant to methotrexate. Murphy-Sturm lymphosarcoma, which is extremely sensitive to methotrexate, was not inhibited by DAMP. In contrast, 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine (DDMP) inhibited the growth of the Murphy-Sturm and Walker tumors. The toxicity of DAMP and DAEP was charaxterized by convulsions followed by death; DDMP did not show such toxicity at median lethal doses. DAEP and DAMP reversibly reduced the number of polymorphonuclear leukocytes in the peripheral blood of rats, and DAMP also decreased the lymphocytes and platelets; DDMP markedly reduced all these cellular elements. Consistently, bone marrow was also markedly depressed by DDMP.

Adamantane↗
PubMed1977

Glucocorticoid activity of various progesterone analogs: correlation between specific binding in thymus and liver and biologic activity.

When tested in an in vitro assay system, progesterone and various analogs of this steroid were shown to compete with [3H] triamcinolone acetonide (TA) for specific glucocorticoid receptors in both rat liver and thymus. Of these analogs, the following derivatives of progesterone were potent competitors of TA binding and, when injected into adrenalectomized rats, induced regression of the thymus and marked increases in hepatic tyrosine aminotransferase activity: 11 beta-hydroxyl, 6 alpha-methyl, 6 alpha, 16 alpha-dimethyl, and 6 alpha-methyl-17 alpha-hydroxyl. In contrast, progesterone, 16 alpha-methyl, and 17 alpha-hydroxy progesterone competed with TA in vitro but failed to elicit either gluco- or antiglucocorticoid activity in vivo. Also, we observed that the oral contraceptive 6 alpha-methyl-17-(1-propynyl)testosterone competes very effectively with TA in a cell-free preparation of rat liver and induces an increase in hepatic tyrosine aminotransferase activity. The 11 beta-hydroxyl group has previously been thought to be essential for glucocorticoid activity. Our studies indicate that substitution of progesterone or testosterone with a 6 alpha-methyl group negates the need for an 11 beta-hydroxyl substitutuent as a prerequisite for glucocorticoid activity.

Animals↗
PubMed1977

Glucocorticoid receptors in Morris hepatomas and host liver and the correlation of biological activity with receptor levels.

Glucocorticoid-binding macromolecules were examined in Morris hepatomas 7787, 5123tc, 3683F, 7800, and 3683 and the Reuber hepatoma H-35 with the use of the synthetic glucocorticoid, triamcinolone acetonide. The physical properties of the triamcinolone acetonide-binding macromolecules of the hepatomas indicate that they are specific glucocorticoid receptors. The equilibrium association constants (Ka), sedimentation coefficients, and sensitivity to sulfhydryl-blocking reagents were found to be similar when hepatoma receptors were compared with the known properties of the liver receptor. Probably the most convincing criterion that the triamcinolone acetonide-binding macromolecules from the hepatomas are specific receptors is that 50 to 90% of the receptor can be depleted from hepatoma cytosol by treating rats with cortisol. In adrenalectomized tumor-bearing rats, the receptor levels in hepatomas 7787, 7800, 5123tc, and H-35 are comparable to or greater than receptor levels of host liver. However, tryptophan oxygenase was not responsive to glucocorticoids in hepatoma 7800 although receptor levels were quite high, and there were no indications that the receptor molecules were altered. Hepatomas 3683 and 3686F have low levels of receptor which may be related to resistance of these tumors to glucocorticoid treatment.

Animals↗
PubMed1977

Nuclear binding of steroid-receptor complex to lymphosarcoma P1798 resistant and sensitive cells and effect of concanavalin A on receptor levels.

Glucocorticoid-resistant P1798 cell lines have been found to contain levels of glucocorticoid receptor comparable to receptor levels in glucocorticoid-sensitive P1798 cells. Previously, most of the P1798 resistant cells examined were found to contain low levels of glucocorticoid receptor, and this was thought to account for the resistance of these cells to glucocorticoid treatment. Resistant cells with high receptor levels exhibited 10 to 50 percent lower levels of nuclear binding than did sensitive cells. In addition, 90 percent of the glucocorticoid-receptor complex could be extracted from resistant nuclei with 0.2 M NaCl, while only 55 percent of the complex could be extracted from sensitive nuclei, indicating that the affinity of the hormone-receptor complex for resistant nuclei may be weaker than the affinity of the hormone-receptor complex for sensitive nuclei. The effect of concanavalin A was also examined in P1798 sensitive and resistant cells. Concanavalin A effectively lowered glucocorticoid receptor levels in the sensitive cells by 45 percent, while receptor levels of the resistant cells were only slightly lowered. The effect of concanavalin A was both temperature dependent (effective at 37 degrees but not 0 degrees) and time dependent. Thus glucocorticoid resistance of P1798 cells appears to have a more complex mechanism than previously proposed.

Animals↗
PubMed1976

Interaction of glucocorticoid hormones with rat skeletal muscle: catabolic effects and hormone binding.

The mechanism of action of glucocorticoid hormones on rat skeletal muscle was studied by following their effect on muscle weight, free amino acid content, activity of amino acid-metabolizing enzymes, and binding to cytoplasmic receptor proteins. A significant reduction of gastrocnemius muscle and body weight occurred following administration of cortisol, triamcinolone diacetate, and triamcinolone acetonide to adrenalectomized rats. Treatment with triamcinolone diacetate also reduced the level of several free amino acids and enhanced the activity of a myofibrillar protease in skeletal muscle. The hormone had, however, no effect on the activity of various enzymes involved in amino acid catabolism in muscle. In nephrosis, another condition of muscle wasting, the level of several muscle amino acids were also reduced to a lesser extent. Cortisol and triamcinolone acetonide, both of which induce muscle wasting, were found to bind to two distinct cytoplasmic proteins in muscle. Binding of the labeled hormones was followed at 0 C and could be observed in presence of a 1000-fold excess of the catabolically inactive steroid epicortisol. Binding of 3H-triamcinolone acetonide. In vitro competition experiments further suggest a correlation between steroid binding to the 3H-dexamethasone or 3H-triamcinolone acetonide site and their potency to induce muscle catabolism. It is concluded that skeletal muscle is a direct target organ for glucocorticoids, and that muscle responsiveness involves binding of the active hormones to cytoplasmic receptor sites.

Amino Acids↗
PubMed1975

Cortisol binding in rat skeletal muscle.

Studies of the reversible binding of [3H]cortisol by rat gastrocnemius muscle cytoplasm in vitro reveal specific binding in the 27,000 times g supernatant fraction at 0 degrees. The [3H]cortisol-binding molecule had an apparant Kd value of 1.7 times 10-7 M and the number of binding sites was 0.99 pmol per mg of cytosol protein. Only a single class of [3H]cortisol-binding sites could be detected, whose protein nature was suggested by its susceptibility to nagarse. The [3H]cortisol-protein complex sedimented at similar to 4 S in a 5 to 20% sucrose gradient either in the presence or absence of 0.3 M KCl. Binding increased more than 2-fold in adrenalectomized rats and was markedly reduced in the muscle of rats pretreated with cortisol. In contrast to the binding of [3H]dexamethasone and [3H]triamcinolone acetonide to receptor proteins in muscle, no correlation was found between the ability of various steroids to complete wtth [3H]cortisol binding and their glucocorticoid potency: [3H]cortisol binding was inhibited by a 1000-fold higher concentration of unlabeled cortisol and progesterone but not by dexamethasone or triamcinolone acetonide. It is therefore suggested that the [3H]cortisol-binding reaction is not directly involved in the biological effects of all potent glucocorticoids in skeletal muscle. The [3H]cortisol-binding protein in muscle cytosol could not be unequivocally distinguished from rat plasma corticosteroid-binding globulin, because both had similar steroid specificity and temperature stability, were not markedly affected by--SH reagents, and displayed similar sedimentation properties.

Adrenal Glands↗
PubMed1975

Interaction of anabolic steroids with glucocorticoid receptor sites in rat muscle cytosol.

While glucocorticoid hormones act catabolically on skeletal muscle through their binding to glucocorticoid-specific receptors in the cytosol, androgens exert anabolic responses but no androgen-specific binding proteins could be detected in this responsive tissue. However, various nonradioactive androgens were effective in displacing labeled dexamethasone or cortisol from their respective cytoplasmic receptors in muscle, both in vitro and in vivo. The inhibition of glucocorticoid binding by androgens is competitive, and could be observed following a single or repeated administration of the androgens to adrenalectomized-castrated animals. The synthetic androgen fluoxymesterone and the hormone testosterone displayed Ki values of 7.5 X 10(-6) M and 1 X 10(-5) M, respectively, for the inhibition of [3H]dexamethasone binding in muscle cytosol. On the basis of competition experiments it is postulated that interaction of androgens with glucocorticoid receptors prevents the binding of glucocorticoids and might be responsible in part for the anabolic effects of pharmacologic doses of androgens in muscle.

Anabolic Agents↗