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J Fried

Publications and source records attributed to J Fried.

At least 73 records · Page 4Linked to original sources
PubMed1979

Prostaglandin F2 alpha and its 13-dehydro analogs: comparative luteolytic effects in vivo.

Prostaglandin F2 alpha (PGF2 alpha) was identified as a luteolytic hormone in sheep (Nature, New Biol. 238, 129, 1972). Attempts to use PGF2 alpha for the pharmacological control of luteolysis in normal cycling sheep met with only partial success due to the rapid clearance of PGF2 alpha from the blood. In addition treated animals showed moderate to severe cardiovascular and gastrointestinal side effects. Accordingly, experiments were carried out to determine whether PG analogs might be more effective as pharmacological luteolytic agents. These compounds, which consisted of a number of the 13-dehydro analogs of PGF2 alpha, were administered to both sheep and monkeys either directly into the ovary or into the systemic circulation to examine them respectively for direct luteolytic activity and for resistance to metabolism. In addition in both the sheep and the monkey smooth muscle activity of the analogs was determined by recording uterine contractions in vivo. Several 13-dehydro analogs including some 16-fluoro derivatives were shown to have luteolytic activity equal to, or in some cases greater than, PGF2 alpha itself. Furthermore most of these compounds showed a marked resistance to the 15-OH-PG-dehydrogenase enzyme in vivo as evidenced by their luteolytic activity when infused intravenously. In terms of uterine contractions, several luteolytic analogs showed markedly diminished smooth muscle activity, and in some cases, complete absence of activity. These results suggest that the receptors governing the luteolytic effect on the one hand, and the smooth muscle effect on the other, possess different structural specificities. Recent studies which we have carried out on the effect of PGF2 alpha on corpus luteum (CL) blood flow support this conclusion. CL capillary blood flow was continuously monitored by means of a miniaturized Geiger-Müller probe inserted through the center of the CL in both the in situ and the autotransplanted ovary of the sheep. Capillary blood flow was measured by the clearance rate of 85Krypton injected periodically into the ovarian artery before and during the induction of luteolysis with PGF2 alpha. It was concluded that the initiation of luteolysis is not dependent on a smooth muscle effect of PGF2 alpha on the capillaries of the CL, a finding which supports the results with the synthetic analogs devoid of smooth muscle activity. More recently, in the primate model used (Macaca fascicularis) we have demonstrated that certain metabolically stable analogs are luteolytic when given intravenously, subcutaneously, or orally. These results demonstrate a rational approach to both drug synthesis and biological evaluation and suggest that a once-a-month contraceptive agent, based on a luteolytic analog of PGF2 alpha, devoid of smooth muscle activity (side effects) and metabolically stable in the bloodstream may become a reality.

Animals↗
PubMed1979

Multi-user system for analysis of data from flow cytometry.

A new program is described for the analysis of DNA histograms from flow cytometry. The fundamental model representing the cell population is similar to one described previously. It assumes the population is grouped into compartments, each consisting of cells having approximately the same DNA content. After staining the cells with an appropriate fluorochrome, the fluorescence distribution of cells within each compartment is assumed to be Gaussian. In the present algorithm, the parameters of the model can either be computed directly by the program from the data, or can be specified as input by the user. When synchronous cell populations lacking distinct G1 and G2/M phases are analyzed, the parameter values must first be obtained using an appropriate control. Percentages of cells in the various compartments are computed using a gradient search method described by Bevington.

Computers↗
PubMed1979

Comparison of substrate specificities of the human placental NAD- and NADP-linked 15-hydroxyprostaglandin dehydrogenases.

A study of the relative activity of the purified placental NAD- and NADP-linked 15-hydroxyprostaglandin dehydrogenases with various prostaglandins and thromboxane B2 (TxB2) suggests that most, if not all, oxidation in the placenta of the 15-hydroxyl group of prostaglandins of the A, E, and F series as well as PGI2 (prostacyclin) and 6-keto PGF1 alpha is catalyzed by the NAD-linked enzyme. Prostaglandin B1 is an excellent substrate for the NADP-linked enzyme. Despite the conformational similarities between PGB1 and PGI2, the latter molecule is a poor substrate for the NADP-linked enzyme. Thromboxane B2 is not oxidized by the NAD-linked enzyme and is oxidized slowly by the NADP-linked enzyme.

Female↗
PubMed1979

Vascular smooth muscle activity of 7-oxa-13-prostynoic acid.

The effects of 7-oxa-13-prostynoic acid (7-OPA), alone and as an antagonist of PGE2 and PGF2alpha, were investigaed in isolated rabbit aortic and canine renal arterial (diameter approximentaly 0.5 mm) strips. 7-OPA caused contractions in both preparations; threshold concentrations were 3- to 10-fold higher than the PGs and maximum contraction was 50-60%. In concentrations of 10(-5) M, 7-OPA inhibited contractions by PGF2alpha and PGE2. The same concentration of 7-OPA did not inhibit norepinephrine-induced contractions. These data indicate that 7-OPA is a partial agonist of PG receptors and produces its antagonism of PGE2 and PGF2alpha by that mechanism.

Animals↗
PubMed1978

Mouse spleen lymphoblasts generated in vitro. Recovery in high yield and purity after floatation in dense bovine plasma albumin solutions.

Mouse spleen lymphoblasts, stimulated to divide in vitro, acquired a low cell density and could be separated by isopycnic techniques. Cultured cells were suspended in BPA columns, rho = 1.080, and spun to equilibrium. The method was simple, fast, accomodated large numbers of cells, and was reproducible. It provided lymphoblasts in high yield and purity (at least 80% of the low density cells were blasts). It allowed for the recovery of proliferating cells in their first cell cycle, and did not alter the subsequent ability of cells to proliferate when recultured in vitro. Certain properties of mouse spleen lymphoblasts were analyzed in detail. Lymphoblasts induced by LPS, FCS, con A (tetravalent and succinylated), and MLC were very similar except in the absolute numbers that were induced. The blasts exhibited the classic cytologic features of enlarged nucleoli and abundant cytoplasmic polyribosomes (basophilia). As a population, they were enlarged in size relative to nondividing cells, but this seemed to apply primarily to cells in the S and G2+ M phase of the cell cycle rather than G1. The cell cycle distribution of lymphoblasts was analyzed by flow microfluorometry. By analyzing low density cells obtained at varying intervals after mitogen stimulation, FMF indicated that lymphoblasts enter the S phase of their first cell cycle beginning at 20-24 h after stimulation.

Animals↗
PubMed1978

Mouse spleen lymphoblasts generated in vitro. Their replication and differentiation in vitro.

Mouse spleen lymphoblasts induced with lipopolysaccharide and fetal calf serum were obtained in high yield and purity in their first proliferative cell cycle by floatation in dense bovine plasma albumin columns (3). The blasts were maintained in vitro for 3 more days. The cultures were examined in bulk on each day, and in addition, those cells in S phase initially were tagged with [(3)H]thymidine and followed continuously in vitro. Grain count dilution data indicated that most blasts divided but twice over a 2- to 3-day interval in vitro. [(3)H]Thymidine pulse radiolabeling and flow microfluorometry suggested that at least 50-70 percent of the proliferating blasts withdrew from proliferative activity after 2-3 days of culture. Morphologic studies demonstrated that lymphoblasts persisted as such for 1-2 days in vitro and then matured into typical plasma cells. Many of the blastprogeny had small nuclei and considerable basophilic cytoplasm on Giemsa-stained cell smears; abundant rough endoplasmic reticulum by electron microscopy; and readily detectable cytoplasmic Ig by immunocytochemistry. Reversion of blasts to small lymphocytes could not be detected; however, some blasts persisted even after 3 days of culture. The viability of the cultured lymphoblast was followed by initially tagging the cells with [(3)H]thymidine as well as several other techniques. Little cell death was documented during the first day of culture. The number of labeled progeny increased twofold whereas the grain count halved. But 40- 50 percent of the cell-associated label was lost during each of the second and third days, and fewer labeled progeny than predicted by grain count dilution were identified. The culture medium could not be implicated in this loss of lymphoblast progeny, and we suggest that the maturation of the lymphoblast to a short-lived plasma cell was responsible. Therefore mitogen-stimulated B blasts seem to mature into typical plasma cells after just two cycles of cell division. The plasma cells resemble those produced in situ during an immune response in their cytologic features, withdrawal from active proliferative activity, and short life-span.

Animals↗
PubMed1978

Coronary vasodilator activity of 13,14-dehydroprostacyclin methyl ester: comparison with prostacyclin and other prostanoids.

The effects of a recently synthesized, stable prostacyclin (PGI2) analog, 13,14-dehydro-PGI2 methyl ester, and authentic PGI2 and several other prostanoids on the coronary circulation were investigated in the intact dog by using a new technique to measure coronary sinus blood flow. The PGI2 analog, PGI2, and prostaglandin (PG) E2 and D2 each increased coronary sinus blood flow in a dose-related fashion when injected into the left coronary artery. The analog and PGE2 had similar vasodilator activity while PGI2 was slightly more potent. PGD2 was a moderately active coronary vasodilator whereas PGF2alpha was inactive. The coronary vasodilator effects of PGI2, its analog, PGE2, and PGD2 occurred at doses that had little effect on aortic pressure, left ventricular pressure and its first derivative, or on cardiac output and heart rate. The prostaglandin precursor arachidonic acid and the endoperoxide intermediate PGH2 both increased coronary sinus blood flow in a dose-dependent manner. The effects of arachidonic acid were inhibited by indomethacin. These data show that PGE2, PGI2, and a stable PGI2 analog are potent vasodilators in the canine coronary vascular bed and suggest that the vasodilator effects of arachidonic acid and PGH2 may be due to the formation of PGE2, PGD2, or PGI2 in the dog heart.

Animals↗
PubMed1978

Rapid hypotonic method for flow cytofluorometry of monolayer cell cultures. Some pitfalls in staining and data analysis.

The rapid hypotonic staining procedure developed by Krishan for DNA determinations by flow cytofluorometry has been proven accurate for in vivo cell samples and for cell lines growing in suspension culture. We show that the unmodified procedure may produce distorted DNA histograms when used for staining cells growing in monolayer cultures, however. To eliminate these distortions, it was necessary to avoid the use of trypsin by staining the attached cells directly, using a hypotonic fluorochrome solution to which nonionic detergent was added. Two sublines of HeLa S3 cells are shown to exhibit major differences in their staining characteristics. By using our revised staining procedure, the two sublines appear to produce very satisfactory DNA histograms. However, in only one subline does the S phase fraction calculated from the histograms agree with the autoradiographical labeling index. Mitotic cells remain intact under these staining conditions, and the principal observed effect of nonionic detergents in this case is to decrease the coefficient of variation of fluorescence intensity.

Cells, Cultured↗
PubMed1977

Relationship of a T-lymphocyte marker to phase of cell cycle and morphology of leukemic cells.

Spontaneous rosette formation with sheep erythrocytes (SRBC) was studied in the peripheral blood and bone marrow lymphoid cells from a patient whose leukemic cells appeared to be T-lymphocytes. Simultaneous morphological examination of the peripheral blood white cells indicated that they consisted of 21% lymphoblast; 26% prolymphocytes and 48% mature lymphocytes. The distribution of bone marrow cells within the cell cycle was determined by flow microfluorometry and 7 hours after treatment with vincristine consisted of 69% in G1, 21% in S, and 9% in mitosis. Since virtually all the cells both in marrow and blood formed rosettes with SRBC this implies that the expression of this T cell marker is independent both of the morphological appearance of these cells and their position within the cell cycle.

Adult↗
PubMed1977

Transient inhibition of initiation of S-phase associated with dimethyl sulfoxide induction of murine erythroleukemia cells to erythroid differentiation.

The murine erythroleukemia cell (MELC) line in suspension culture can be induced to differentiate to erythroid cells by various compounds, including dimethyl sulfoxide (Me2SO). Analysis of the cell cycle, during differentiation induced by Me2SO, using thymidine incorporation, thymidine labeling index, and relative DNA content per cell as measured by flow microfluorometry, demonstrates a transient inhibition of entry of cells into S-phase of the cell cycle which is detected as early as 5 hr and is maximal about 20 hr after beginning of nonsynchronous cultures. Furthermore, in the presence of Me2SO there is restricted binding of the intercalating dye propidium iodide to chromatin from MELC in G1 phase of the cell cycle, as early as 10 hr of culture. This restricted binding of propidium iodide to chromatin is observed in MELC cultured with other inducing agents, such as butyric acid and dimethyl-acetamide, but is not detected with an Me2SO-resistant cell line cultured with Me2SO.

Cell Differentiation↗
PubMed1977

Unusual pulmonary vasodilator activity of 13,14-dehydroprostacyclin methyl ester: comparison with endoperoxides and other prostanoids.

Microsomes from stomach fundus and blood vessels transform the endoperoxide, PGH2, into a newly discovered unstable substance, PGI2, that relaxes arterial strips and inhibits platelet aggregation. 13,14-Dehydro-PGI2 methyl ester, a newly synthesized, stable PGI2 analog, was found to have potent vasodilator activity in the feline and simian pulmonary vascular bed. The PGI2 analog decreased lobar arterial perfusion pressure in the intact cat and monkey. Because pulmonary blood flow was held constant and left atrial pressure was unchanged, the decrease in perfusion pressure reflects a decrease in pulmonary vascular resistance. The dilator response was unusual in that it persisted for 10-12 min, whereas the response to PGE1, the only other vasodilator prostaglandin in the mature animal, persisted for only 1-2 min. The dilator response to the PGI2 analog was enhanced when pulmonary vascular resistance was increased. This substance had less effect on cardiac output and aortic pressure than PGE1, whereas it was a more potent pulmonary vasodilator. These data demonstrate that prostacyclin-like substances possess novel vasodilator activity in the pulmonary circulation and suggest a therapeutic use in the treatment of pulmonary hypertensive diseases.

Animals↗
PubMed1977

Synthesis of 13,14-dehydroprostacyclin methyl ester: a potent inhibitor of platelet aggregation.

The structure of the most recently discovered, biologically highly active prostaglandin, PGI2 or prostacyclin, is correctly predicted on biogenetic grounds, and a general synthesis starting with prostaglandins of the F2alpha series is reported. Starting with the biologically active 13,14-dehydro-PGF2alpha, the synthesis involves formation of a 5-bromo-6,9alpha-epoxy derivative, followed by esterification and dehydrobromination of the methyl ester to form the prostacyclin structure. The stereochemistry at C-5 and C-6 of all reported products is assigned on the basis of experimental findings and mechanistic reasoning. 13,14-Dehydroprostacyclin methyl ester is considerably more stable at pH 7.5 than prostacyclin. It inhibits platelet aggregation induced by a variety of agents and causes an increase in renal blood flow in the dog at nanomolar levels.

Animals↗