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Biomedical subjects

E Friedman

Publications and source records attributed to E Friedman.

At least 505 records · Page 28Linked to original sources
PubMed1984

Antidepressant drugs with varying pharmacological profiles alter rat pineal beta adrenergic-mediated function.

The effects of acute and chronic administrations of two antidepressant drugs with differing pharmacological profiles on pineal beta adrenergic receptor-mediated functions were examined in the rat. Animals were treated with control powdered food or with either imipramine or iprindole-containing diets (0.067%, w/w) for various time intervals. Animals were sacrificed during different phases of the light/dark cycle and pineal [3H]dihydroalprenolol (DHA) binding, N-acetyltransferase (NAT) activity, N-acetylserotonin (NAS) and melatonin levels were measured. Plasma drugs and metabolite concentrations were also assessed. A 3-day treatment with imipramine resulted in an unchanged pineal [3H] DHA binding and an increase in pineal serotonin (5-HT), NAS and melatonin. A comparable treatment with iprindole did not alter any pineal measures. Three weeks of imipramine treatment resulted in therapeutic plasma drug and metabolite concentrations and elicited a reduction (31%) in the density of pineal [3H] DHA binding. This treatment, in addition, suppressed the dark-induced activation of the intracellular enzyme NAT (38%) and the concentrations of NAS (25%) and melatonin (23%) without altering pineal 5-HT rhythm. No apparent shift was observed in the NAT, NAS and melatonin rhythms. Chronic treatment with the atypical antidepressant iprindole for 3 weeks resulted in-plasma iprindole concentrations of 76 ng/ml and a significant reduction (24%) in pineal 5-HT levels 5 hr into the dark phase of the light/dark cycle. Pineal NAT activity and NAS and melatonin content were not significantly reduced by this treatment. However, 4 weeks of iprindole ingestion produced plasma drug concentrations of 141 ng/ml and significantly reduced pineal [3H] DHA binding density (18%) without changing binding affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetyltransferases↗
PubMed1984

A model for human colon carcinoma evolution based on the differential response of cultured preneoplastic, premalignant, and malignant cells to 12-O-tetradecanoylphorbol-13-acetate.

Small colonic adenocarcinomas can be found in focal areas within benign tumors (adenomas), strongly suggesting an adenoma-to-carcinoma sequence. The induction of plasminogen activator (PA) secretion by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) has been used to order histologically distinct classes of human colonic adenomas in primary culture into a sequence from the most benign to the most advanced premalignant state. This ordering is based on the observation that each of five carcinomas examined in an earlier study by E. A. Friedman (Cancer Res., 41: 4588-4599, 1981) and each of seven carcinomas tested in this study released PA in response to TPA, inducing easily scored morphological alterations. Benign tumors either resembled carcinomas in their response to TPA or exhibited no morphological changes. The most benign adenomas by histopathology criteria were the small pure tubular adenomas without dysplasia. Six of seven of these adenomas did not secrete PA in response to TPA. We concluded that malignant cells had acquired the ability to respond to TPA by PA secretion, while tubular adenoma cells were not an advanced enough preneoplastic stage to so respond. TPA treatment of two cultured villous adenomas, one with infiltrating carcinoma and one with focus of moderately dysplastic cells, in the presence of low serum to decrease the plasmin concentration, demonstrated that only a subpopulation of cells secreted PA. Local areas of the monolayer were morphologically altered by the protease, forming clusters of cells loosely attached to the dish. The presence of such subpopulations within cultured adenomas was demonstrated by screening an additional five villous adenomas, 15 villotubular adenomas, and 11 tubular adenomas. The presence of dysplastic cells in 23 of 24 cases correlated with PA secretion. A subpopulation of villous cells, in the absence of dysplastic cells in each of three cases, also secreted PA. We conclude that, during tumor evolution, this villous subpopulation is the first preneoplastic cell type to acquire responsiveness to TPA by PA secretion. This property is maintained as the cells further evolve through premalignant dysplastic stages to carcinoma.

Adenoma↗
PubMed1984

Actin cytoskeletal organization loss in the benign-to-malignant tumor transition in cultured human colonic epithelial cells.

The colonic epithelium in vivo is a highly indented sheet one cell thick. Culture methods have been developed to allow the normal cellular migration of the cells comprising this sheet to flatten it into a patch on the surface of a Petri dish [Friedman, E. A., Higgins, P.J., Lipkin , M., Shinya , H., and Gelb , A.M., In Vitro (Rockville), 17: 632-644, 1981]. Actin cytoskeletal organization was analyzed in such epithelial "patches" derived from several human colonic adenocarcinomas and their precursors, adenomas (benign tumors). The actin cytoskeleton was visualized by fluorescence microscopy after the fixed, permeabilized cells were stained with rhodamine-conjugated phalloidin. This drug has a very high affinity for actin filaments and a much lower affinity for monomeric actin. Actin organization was scored from 0 (no cables) to 5 points (extensive intercellular cable network). The phalloidin-stained actin found in seven adenocarcinomas had a predominantly granular fluorescence pattern with very little cable organization, scoring an average of 0.9 +/- 0.8 (S. D.). Three established cell lines derived from human colon carcinomas contained no cables by this analysis, scoring 0.0 +/- 0.0. In marked contrast, all 12 of the cultured adenomas had extensive actin cable networks, scoring an average of 4.3 +/- 0.4. There was no statistical difference between adenomas of differing histopathology class and malignant potential. However, cytoskeletons of plasminogen-activator-secreting "late-stage" preneoplastic cells from adenomas became disorganized by exposure to 12-O-tetradecanoyl-phorbol-13-acetate or another tumor promoter, teleocidin B. They scored, respectively, average actin organization values of 0.0 +/- 0.0 and 0.4 +/- 0.6. In contrast, nonplasminogen -activator- secreting "early-stage" preneoplastic cells from less advanced benign tumors were unaffected by 12-O-tetradecanoyl-phorbol-13- acetate or teleocidin B and retained extensive actin organization. Most, if not all, adenocarcinomas arise from preexisting preneoplastic adenomatous cells. Thus, loss of actin organization appears to mark the transition of noninvasive benign colonic tumors to invasive malignant tumors in humans. This transition is mimicked in vitro by exposure of certain "late-stage" preneoplastic cells to a tumor promoter which induces secretion of a plasminogen activator.

Actins↗
PubMed1984

12-O-Tetradecanoylphorbol-13-acetate stimulation of DNA synthesis in cultured preneoplastic familial polyposis colonic epithelial cells but not in normal colonic epithelial cells.

We have developed a method for the routine primary culture of human colonic epithelial cells. Cultured cells exhibited characteristic epithelial structures, including a brush border and junctional complexes. Flask-like goblet cells containing mucus were also seen within the epithelial monolayer. [3H]Thymidine labeling indices were used to distinguish between cultured cells from familial polyposis patients, other patients at high risk to develop colon cancer, and low-risk control subjects. 12-O-Tetradecanoylphorbol-13-acetate (TPA) at 10 ng/ml enhanced DNA synthesis an average of 8-fold when assayed by labeling index in colonic epithelial cells from five of six familial polyposis patients. No such stimulation by TPA was seen in cells from 13 high-risk patients without familial polyposis or in cells from five low-risk subjects. Hundreds of benign polyps can be found in the colons of familial polyposis patients. One such benign tubular adenoma exhibited the same enhancement of DNA synthesis by TPA as normal-appearing epithelial cells from a biopsy adjacent to that polyp. Mitogenic response to TPA had been seen earlier in cells from each of four tubular adenomas (Friedman, E. Cancer Res., 41: 4588-4599, 1981). Both familial polyposis epithelial cells and adenoma cells are considered preneoplastic, but they are not identical because their patterns of actin cytoskeletal organization differ. These results imply that familial polyposis epithelial cells are precursors of tubular adenoma cells, and their transition to the more advanced preneoplastic cells of this benign tumor is influenced by endogeneous tumor promoters.

Cells, Cultured↗
PubMed1983

A system man.

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Hospital Administration↗
PubMed1983

Sharing the wealth.

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Community-Institutional Relations↗
PubMed1983

Prediction of early course of breast carcinoma by thymidine labeling.

The thymidine labeling index (TLI) was measured in vitro in 278 primary breast carcinomas. In 227 operable women treated by radical mastectomy, TLI's below the median of 4.55% carried a probability of relapse of 20% at four years, in contrast to 52% for TLI's above the median (P = 0.0001). The probability of relapse was significantly related to the TLI independent of TNM pathologic stage, axillary lymph nodal status alone, estrogen receptor (ER) content, or menopausal status. The abilities of the TLI and nodal status to predict early relapse were equally strong and independent, whereas other variables tested had less or no independent predictive capacity. The predictive value of the ER content depended largely on its relationship to the TLI, and ER was related to the probability of relapse in the below median TLI group only. The TLI can select a subgroup of node-negative patients with a relapse-expectancy of approximately 50% at four years.

Breast Neoplasms↗
PubMed1983

Effects of chronic antidepressant treatment on serotonin receptor activity in mice.

The effect of acute and chronic treatments with conventional and atypical antidepressant drugs on serotonin receptor activity was assessed by the responsiveness of mice to the serotonin receptor agonist 5-methoxy-N,N-dimethyltryptamine. Acute treatment with 10 mg/kg of amitriptyline, imipramine, trazodone, mianserin or viloxazine reduced the head twitch response measured 1 h following a challenged dose of the serotonin agonist. Acute iprindole and desmethylimipramine, however, had no effect on the serotonergic response. Chronic treatment with the clinically effective antidepressants amitriptyline, imipramine, desmethylimipramine, iprindole, and trazodone produced an enhanced responsiveness to 5-MeODMT. The enhanced responsiveness was first observed 24 h after cessation of treatment with most drugs. The effect lasted for at least 48 h. Chronic treatment with the neuroleptic haloperidol did not result in altered responsivity to the serotonin agonist. Brain accumulation of imipramine and amitriptyline and their deaminated metabolites were measured. Brain drug and metabolite levels peaked 1 h following both acute and chronic treatments. Brain accumulations of amitriptyline and its metabolite were much greater than those of imipramine and its metabolite. This pharmacokinetic data is consistent with an early (1 h) antagonism of the 5-MeODMT response and the emergence of hightened responsiveness to 5-MeODMT after chronic treatment, when brain drug levels are reduced. These findings are also consistent with the greater inhibitory effect found after treatment with amitriptyline than with imipramine. It is concluded that enhanced serotonin neurotransmission which develops during chronic treatment with antidepressant drugs may be related to the clinical action of these drugs.

Amitriptyline↗