GLUCOCORTICOID EFFECTS ON VASCULAR CONNECTIVE TISSUE DURING REPAIR. IMPORTANCE OF DOSE LEVEL AND PRE- AND POST-INJURY TREATMENT

1977 ◽  
Vol 86 (2) ◽  
pp. 437-448 ◽  
Author(s):  
R. Mathorpe ◽  
C. Garbarsch ◽  
B. Kofod ◽  
I. Lorenzen
Keyword(s):  
Connective Tissue ◽  
Inhibitory Action ◽  
Amino Nitrogen ◽  
Dependent Manner ◽  
Intimal Thickening ◽  
Descending Thoracic Aorta ◽  
Post Injury ◽  
Collagen Protein ◽  
Injury Treatment ◽  
Dose Dependent

ABSTRACT Aorta of male albino rabbits were subjected to a single mechanical dilatation injury and the effects of different daily doses of prednisolone on the metabolism of collagen and glycosaminoglycans as well as on the content of alpha-amino nitrogen, RNA, DNA, water and fat and the histology of the descending thoracic aorta were analyzed 10 days after the injury. The effects of pre- and post-injury treatment with prednisolone were compared. Prednisolone inhibited the intimal thickening. This effect was enhanced by pre-injury treatment. Prednisolone also inhibited the biosynthesis of non-dialysable [14C]hydroxyproline-collagen, but increased the relative degradation of collagen in a dose dependent manner. The biosynthesis of glycosaminoglycans was decreased while prednisolone had no effect on the concentration and total amount of glycosaminoglycans, collagen, protein, RNA, DNA and fat. Finally the aortic content of water was decreased during treatment with prednisolone also in a dose dependent manner. It is concluded that the action of prednisolone on vascular collagen and water during repair is dose dependent and that the inhibitory action of prednisolone on the intimal thickening is enhanced by pre-injury treatment.

scholarly journals TGF-β Signaling Cooperates with AT Motif-Binding Factor-1 for Repression of the α-Fetoprotein Promoter

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Nobuo Sakata ◽  
Satoshi Kaneko ◽  
Souichi Ikeno ◽  
Yutaka Miura ◽  
Hidekazu Nakabayashi ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Inhibitory Action ◽  
Fetal Liver ◽  
Direct Interaction ◽  
Detectable Level ◽  
Dependent Manner ◽  
Reporter System ◽  
Adult Liver ◽  
Binding Factor ◽  
Dose Dependent

α-Fetoprotein (AFP) is known to be highly produced in fetal liver despite its barely detectable level in normal adult liver. On the other hand, hepatocellular carcinoma often shows high expression of AFP. Thus, AFP seems to be an oncogenic marker. In our present study, we investigated how TGF-β signaling cooperates with AT motif-binding factor-1 (ATBF1) to inhibit AFP transcription. Indeed, the expression of AFP mRNA in HuH-7 cells was negatively regulated by TGF-β signaling. To further understand how TGF-β suppresses the transcription of the AFP gene, we analyzed the activity of the AFP promoter in the presence of TGF-β. We found that the TGF-β signaling and ATBF1 suppressed AFP transcription through two ATBF1 binding elements (AT-motifs). Using a heterologous reporter system, both AT-motifs were required for transcriptional repression upon TGF-β stimulation. Furthermore, Smads were found to interact with ATBF1 at both its N-terminal and C-terminal regions. Since the N-terminal (ATBF1N) and C-terminal regions of ATBF1 (ATBF1C) lack the ability of DNA binding, both truncated mutants rescued the cooperative inhibitory action by the TGF-β signaling and ATBF1 in a dose-dependent manner. Taken together, these findings indicate that TGF-β signaling can act in concert with ATBF1 to suppress the activity of the AFP promoter through direct interaction of ATBF1 with Smads.

scholarly journals Effects of a phorbol ester and clomiphene on protein phosphorylation and insulin secretion in rat pancreatic islets

1988 ◽  
Vol 249 (3) ◽  
pp. 825-830 ◽  
Author(s):  
S J Hughes ◽  
S J Ashcroft
Keyword(s):  
Insulin Release ◽  
Inhibitory Action ◽  
Glucose Oxidation ◽  
Subcellular Fractionation ◽  
Mean Value ◽  
Particulate Fraction ◽  
Dependent Manner ◽  
Phosphorylation State ◽  
Kinase C ◽  
Dose Dependent

The potentiation of glucose-stimulated insulin release induced by 100 nM-12-O-tetradecanoylphorbol 13-acetate (TPA) was inhibited by clomiphene, an inhibitor of protein kinase C (PK C), in a dose-dependent manner. Clomiphene at concentrations up to 50 microM had a modest inhibitory action (27%) on insulin release stimulated by 10 mM-glucose alone, but had no effect on the potentiation of insulin release induced by forskolin. Islet PK C activity, associated with a particulate fraction, was stimulated maximally by 100 nM-TPA. This stimulation was blocked by clomiphene in a dose-dependent manner, with 50% inhibition at 30 microM. Incubation of intact islets with TPA after preincubation with [32P]Pi and 10 mM-glucose to label intracellular ATP resulted primarily in enhanced phosphorylation of a 37 kDa protein (mean value, +/- S.E.M., 36,700 +/- 600 Da; n = 7). This increased phosphorylation was blocked by the simultaneous inclusion of clomiphene. Subcellular fractionation revealed the presence of the 37 kDa phosphoprotein in a 24,000 g particulate fraction of islet homogenates. Neither clomiphene nor TPA affected the rate of glucose oxidation by islets. These results show that the phosphorylation state of a 37 kDa membrane protein parallels the modulation of insulin release induced by TPA and clomiphene and support a role for PK C in the insulin-secretory mechanism.

Effect of PGE1, PGI2, and PGF2α analogs on collagen gel compaction in vitro and interstitial pressure in vivo

1998 ◽  
Vol 274 (2) ◽  
pp. H663-H671 ◽  
Author(s):  
Ansgar Berg ◽  
Anna-Karin Hultgård Ekwall ◽  
Kristofer Rubin ◽  
Johan Stjernschantz ◽  
Rolf K. Reed
Keyword(s):  
Connective Tissue ◽  
Interstitial Fluid ◽  
Circulatory Arrest ◽  
Collagen Gel ◽  
Fluid Volume ◽  
Dependent Manner ◽  
Edema Formation ◽  
Interstitial Fluid Volume ◽  
Dose Dependent ◽  
Contraction Assay

Acute inflammation in skin is accompanied by increased negativity of interstitial fluid pressure (PIF), which will increase capillary fluid filtration and thereby potentiate edema formation. A series of studies indicates that the connective tissue cells in rat dermis are involved in the control of PIF and mediate this response. The present study describes a novel effect of prostaglandin (PG) E1 isopropyl ester, carbaprostacyclin (PGI2 analog), and latanoprost (PGF2α analog) on edema formation and PIF in parallel with their action on the fibroblast-populated collagen gel contraction assay. The prostaglandins were injected subdermally in pentobarbital-anesthetized rats. PIF was measured with a servo-controlled counterpressure system after circulatory arrest had been induced with saturated potassium chloride. Circulatory arrest was induced to limit edema formation that would raise interstitial fluid volume and thereby attenuate a possible increased negativity of PIF. PGE1 (0.91 mM) and carbaprostacyclin (1.28 mM) lowered PIF from a control value of −0.8 ± 0.4 mmHg to −3.0 ± 0.4 ( P < 0.01) and −3.7 ± 0.9 ( P < 0.01) mmHg, respectively, within 45 min in a dose-dependent manner. Edema formation was measured in separate experiments. PGE1 and carbaprostacyclin significantly increased interstitial fluid volume (extravascular51Cr-EDTA space) at concentrations as low as 0.1 and 1.1 μM, respectively. Latanoprost had no effect on PIF or edema formation. However, latanoprost reversed, in a dose-dependent manner, an increased negativity of PIF accompanying the anaphylactic reaction to dextran. In the gel contraction assay with human diploid fibroblasts (AG 1518), a corresponding specificity was observed where PGE1 and carbaprostacyclin effectively inhibited gel contraction although latanoprost had no effect. Thus the present data demonstrate a novel effect of prostaglandins and provide further evidence for active modulation of PIF via loose connective tissue cells.

Inhibitory action of peptide YY on gastric acid secretion

1987 ◽  
Vol 253 (3) ◽  
pp. G298-G302 ◽  
Author(s):  
Y. S. Guo ◽  
M. Fujimura ◽  
F. Lluis ◽  
Y. Tsong ◽  
G. H. Greeley ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Inhibitory Action ◽  
Peptide Yy ◽  
Dependent Manner ◽  
Inhibitory Mechanism ◽  
Cholinergic Pathways ◽  
The Face ◽  
Dose Dependent

The purpose of this study is to investigate the effect of peptide YY (PYY) on pentagastrin-, histamine-, and bethanechol-stimulated gastric acid secretion and the possible mechanisms by which PYY inhibits gastric acid secretion. Six mongrel dogs with chronic gastric and duodenal fistulas were given an intravenous infusion of pentagastrin (0.5 microgram . kg-1 . h-1), histamine (18 micrograms . kg-1 . h-1), or bethanechol (80 micrograms . kg-1 . h-1) either alone or simultaneously with intravenous PYY (100, 200, 400, pmol . kg-1 . h-1). PYY (100, 200, 400 pmol . kg-1 . h-1) inhibited pentagastrin-stimulated gastric acid secretion in a dose-dependent manner. PYY (400 pmol . kg-1 . h-1) did not depress bethanechol-stimulated gastric acid secretion. PYY (400 pmol . kg-1 . h-1) also failed to inhibit histamine-stimulated gastric acid secretion. Furthermore, PYY inhibit pentagastrin-stimulated gastric acid secretion in the face of atropine, vagotomy, or indomethacin treatment. These findings indicate that the inhibitory action of PYY on gastric acid secretion is in part independent of long and short cholinergic pathways. These findings also indicate that the inhibitory mechanism of PYY is independent of prostaglandin synthesis. Our findings are discussed in relation to previous reports regarding the effects of PYY on gastric acid secretion.

Cadmium selectively inhibits fibroblast procollagen production and proliferation

1994 ◽  
Vol 267 (3) ◽  
pp. L300-L308 ◽  
Author(s):  
R. C. Chambers ◽  
R. J. McAnulty ◽  
A. Shock ◽  
J. S. Campa ◽  
A. J. Newman Taylor ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Connective Tissue ◽  
Cell Lines ◽  
Fetal Lung ◽  
Lung Fibroblasts ◽  
Dependent Manner ◽  
Fetal Rat ◽  
Rat Fibroblasts ◽  
Human Fetal Lung ◽  
Dose Dependent

Chronic inhalation of cadmium fumes has been associated with the development of emphysema, a disease characterized by extensive disruption of lung connective tissue. Cadmium is also an important contaminant of tobacco and may play a role in cigarette smoking-related emphysema. In this paper we investigated the effect of nontoxic doses of cadmium chloride (CdCl2) on fibroblast procollagen production and proliferation, key features of connective tissue repair following injury. CdCl2 inhibited fibroblast procollagen production in a dose-dependent manner in two different cell lines. For fetal rat fibroblasts, maximal effects were observed at 10 microM CdCl2, with values reduced by 82 +/- 6% (mean +/- SE, n = 6, P < 0.01) relative to control cells. In contrast, noncollagen protein synthesis by these cells was enhanced in the presence of CdCl2. In human fetal lung fibroblasts (HFL1), maximal inhibition of procollagen production (83 +/- 2%, P < 0.01) was observed at 40 microM CdCl2, whereas noncollagen protein synthesis was unaffected. In both cell lines the inhibition of procollagen production was shown to be due to decreased procollagen synthesis and an increase in the proportion of newly synthesized procollagen degraded. Cadmium also affected fibroblast proliferation in response to 2% serum, with values for fetal rat cells depressed by 17 +/- 4, 72 +/- 2, and 86 +/- 4% (all P < 0.01) compared with controls at 1, 5, and 10 microM CdCl2, respectively. These data show that cadmium selectively inhibits fibroblast procollagen production and also attenuates their mitogenic response to serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Low Molecular Weight Heparin and Unfragmented Heparin on Induction of Osteoporosis in Rats

1990 ◽  
Vol 63 (03) ◽  
pp. 505-509 ◽  
Author(s):  
Thomas Mätzsch ◽  
David Bergqvist ◽  
Ulla Hedner ◽  
Bo Nilsson ◽  
Per Østergaar
Keyword(s):  
Molecular Weight ◽  
Bone Mineral ◽  
Low Molecular Weight Heparin ◽  
Zinc Content ◽  
Low Molecular Weight ◽  
Dependent Manner ◽  
Bone Mineral Mass ◽  
Bone Ash ◽  
Dose Dependent ◽  
Mineral Mass

SummaryA comparison between the effect of low molecular weight heparin (LMWH) and unfragmented heparin (UH) on induction of osteoporosis was made in 60 rats treated with either UH (2 IU/ g b w), LMWH in 2 doses (2 Xal U/g or 0.4 Xal U/g) or placebo (saline) for 34 days. Studied variables were: bone mineral mass in femora; fragility of humera; zinc and calcium levels in serum and bone ash and albumin in plasma. A significant reduction in bone mineral mass was found in all heparin-treated rats. There was no difference between UH and LMWH in this respect. The effect was dose-dependent in LMWH-treated animals. The zinc contents in bone ash were decreased in all heparin-treated rats as compared with controls. No recognizable pattern was seen in alterations of zinc or calcium in serum. The fragility of the humera, tested as breaking strength did not differ between treatment groups and controls. In conclusion, if dosed according to similar factor Xa inhibitory activities, LMWH induces osteoporosis to the same extent as UH and in a dose-dependent manner. The zinc content in bone ash was decreased after heparin treatment, irrespective of type of heparin given.

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

Evaluating the Proposed Mechanism by Which Atorvastatin Can Protect Renal Tissue against Contrast Media: An Animal study

2019 ◽  
pp. 75-84
Keyword(s):  
Contrast Media ◽  
Kidney Injury ◽  
Saline Group ◽  
Pleiotropic Effect ◽  
Renal Tissue ◽  
Male Rats ◽  
Dependent Manner ◽  
Group 2 ◽  
Dose Dependent ◽  
Media Group

Contrast- induced nephropathy (CIN) is an elevation of serum creatinine of ≥ 0.5 mg/dL from baseline after two to three days of exposure to contrast substance if there is no other cause for acute kidney injury. Atorvastatin may protect normal kidney physiology from contrast- induced kidney injury by effects unrelated to hypolipidemia termed pleiotropic effect by decline of endothelin production, angiotensin system down regulation, and under expression of endothelial adhesion molecules. This study was conducted to assess the strategy by which atorvastatin can achieve protective effect for kidneys after exposure to contrast media in an animal model. A 40 male rats were distributed randomly into 4 groups; ten rats for each: group (1): given normal saline; group (2): CIN group given iopromide as contrast media; group (3): given atorvastatin (20mg/kg) and iopromide; and group (4): given atorvastatin (40mg/kg) and iopromide. Blood collected by cardiac puncture for detection of serum glutathione, malondialdehyde, matrix metalloproteinase-9, and interleukin-18. The results have shown a significant increase in inflammatory and oxidative stress markers in contrast media group, and significant reduction in these markers in atorvastatin treated groups, in a dose-dependent manner. As conclusion, atorvastatin mechanism for protection against CIN in a dose-dependent manner can mediate by anti-inflammatory and antioxidant effects.

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