AN IN VIVO MODEL FOR TESTING INHIBITION OF ARGININE-INDUCED INSULIN AND GLUCAGON RELEASE BY SOMATOSTATIN ANALOGS

1977 ◽  
Vol 86 (4) ◽  
pp. 833-841 ◽  
Author(s):  
Ariel Gordin ◽  
Chester Meyers ◽  
Akira Arimura ◽  
David H. Coy ◽  
Andrew V. Schally
Keyword(s):  
Animal Model ◽  
Somatostatin Analogs ◽  
Insulin Level ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Glucagon Release ◽  
Plasma Glucagon ◽  
Quantitative Manner ◽  
Dose Dependent

ABSTRACT An animal model for testing the in vivo potency of somatostatin analogs in inhibiting the release of insulin and glucagon is described. The secretion of these pancreatic hormones was stimulated in rat by infusion of arginine. The plasma insulin level increased almost to a maximum after an infusion of 10 min, while plasma glucagon rose more slowly, reaching its maximum only after a 30 min infusion. Concomitant infusion of graded doses of somatostatin (2.5, 10, 40 and 160 μg/100 g BW) for 30 min inhibited both insulin and glucagon release in a dose-dependent manner, enabling us to test somatostatin analogs for insulin and glucagon-suppressive activity in a semi-quantitative manner. Using this animal model, 3 analogs of somatostatin, [D-Cys14]-, [Ala2, D-Cys14]- and [D-Trp8, D-Cys14]somatostatin were tested in a 4-point assay. They all showed dissociated activity in inhibiting the secretion of glucagon more than that of insulin.

The human renin infused rat: use as an in vivo model for the biological evaluation of human renin inhibitors

1999 ◽  
Vol 77 (11) ◽  
pp. 886-895 ◽  
Author(s):  
Gordon Bolger ◽  
Jean-Claude Vigeant ◽  
Francine Liard ◽  
Bruno Simoneau ◽  
Diane Thibeault ◽  
...  
Keyword(s):  
Oral Administration ◽  
Pressor Response ◽  
Biological Evaluation ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Renin Inhibitors ◽  
Human Renin ◽  
Dose Dependent

The human renin infused rat model (HRIRM) was used as an in vivo small-animal model for evaluating the efficacy of a collection of inhibitors of human renin. The intravenous infusion of recombinant human renin (2.4 µg·kg-1·min-1) in the ganglion-blocked, nephrectomized rat produced a mean blood pressor response of 47 ± 3 mmHg (1 mmHg = 133.3 Pa), which was reduced by captopril, enalkiren, and losartan in a dose-dependent manner following oral administration, with ED50 values of 0.3 ± 0.1, 2.5 ± 0.9, and 5.2 ± 1.6 mg/kg, respectively. A series of peptidomimetic P2-P3 butanediamide renin inhibitors inhibited purified recombinant human renin in vitro in a concentration-dependent manner, with IC50 values ranging from 0.4 to 20 nM at pH 6.0, with a higher range of IC50 values (0.8-80 nM) observed at pH 7.4. Following i.v. administration of renin inhibitors, the pressor response to infused human renin in the HRIRM was inhibited in a dose-dependent manner, with ED50 values ranging from 4 to 600 µg/kg. The in vivo inhibition of human renin following i.v. administration in the rat correlated significantly better with the in vitro inhibition of human renin at pH 7.4 (r = 0.8) compared with pH 6.0 (r = 0.5). Oral administration of renin inhibitors also resulted in a dose-dependent inhibition of the pressor response to infused human renin, with ED50 values ranging from 0.4 to 6.0 mg/kg and the identification of six renin inhibitors with an oral potency of <1 mg/kg. The ED50 of renin inhibitors for inhibition of angiotensin I formation in vivo was highly correlated (r = 0.9) with the ED50 for inhibition of the pressor response. These results demonstrate the high potency, dose dependence, and availability following oral administration of the butanediamide series of renin inhibitors.Key words: renin-angiotensin system, recombinant human renin, rat, renin inhibitors.

scholarly journals Inhibition of murine erythroid colony formation in vitro by interferon gamma and correction by interferon receptor immunoadhesin

Blood ◽  
1994 ◽  
Vol 83 (4) ◽  
pp. 911-915 ◽  
Author(s):  
RT Jr Means ◽  
SB Krantz ◽  
J Luna ◽  
SA Marsters ◽  
A Ashkenazi
Keyword(s):  
Animal Model ◽  
Interferon Gamma ◽  
Colony Formation ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Ifn Gamma ◽  
Dose Dependent

It has been previously reported that inhibition of human erythroid colony-forming units (CFU-E) in vitro by interleukin-1 (IL-1) is an indirect effect, occurring through the production of interferon gamma (IFN gamma). IFN gamma, in turn, inhibits CFU-E colony formation directly, and its inhibitory effect can be overcome by exposure to high concentrations of erythropoietin (EPO). To develop an in vitro animal model for investigating inhibition of erythropoiesis by IFN gamma, the effects of recombinant murine (rm) IFN gamma on highly purified CFU-E from the spleens of mice infected with the anemia strain of the Friend virus (FVA) were studied. rmIFN gamma inhibited CFU-E colony formation in a dose-dependent manner. This inhibition occurred with large (> or = 8 cell) colonies only; smaller colonies were not affected. The inhibitory effect was corrected to 72% of control by high EPO concentrations of 64 U/mL. Murine CFU-E were then cultured with rmIFN gamma in the presence of a soluble murine IFN gamma receptor fused to the hinge and Fc domains of the human IgG1 heavy chain (mIFN gamma R-IgG). Inhibition of CFU-E colony formation by rmIFN gamma (100 U/mL) was corrected by mIFN gamma R-IgG in a dose-dependent manner, with an approximate IC50 of 0.05 nmol/L, and complete or near complete correction at 0.5 nmol/L. Similarly, a human IFN gamma R-IgG greatly reduced the inhibitory effect of recombinant human IFN gamma on human CFU-E. These experiments provide an in vitro animal model for studying the inhibitory effects of IFN gamma on erythropoiesis and indicate that IFN gamma R-IgG may be a useful agent for reducing the toxicity of IFN gamma in vivo.

scholarly journals Inhibition of murine erythroid colony formation in vitro by interferon gamma and correction by interferon receptor immunoadhesin

Blood ◽  
1994 ◽  
Vol 83 (4) ◽  
pp. 911-915 ◽  
Author(s):  
RT Jr Means ◽  
SB Krantz ◽  
J Luna ◽  
SA Marsters ◽  
A Ashkenazi
Keyword(s):  
Animal Model ◽  
Interferon Gamma ◽  
Colony Formation ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Ifn Gamma ◽  
Dose Dependent

Abstract It has been previously reported that inhibition of human erythroid colony-forming units (CFU-E) in vitro by interleukin-1 (IL-1) is an indirect effect, occurring through the production of interferon gamma (IFN gamma). IFN gamma, in turn, inhibits CFU-E colony formation directly, and its inhibitory effect can be overcome by exposure to high concentrations of erythropoietin (EPO). To develop an in vitro animal model for investigating inhibition of erythropoiesis by IFN gamma, the effects of recombinant murine (rm) IFN gamma on highly purified CFU-E from the spleens of mice infected with the anemia strain of the Friend virus (FVA) were studied. rmIFN gamma inhibited CFU-E colony formation in a dose-dependent manner. This inhibition occurred with large (> or = 8 cell) colonies only; smaller colonies were not affected. The inhibitory effect was corrected to 72% of control by high EPO concentrations of 64 U/mL. Murine CFU-E were then cultured with rmIFN gamma in the presence of a soluble murine IFN gamma receptor fused to the hinge and Fc domains of the human IgG1 heavy chain (mIFN gamma R-IgG). Inhibition of CFU-E colony formation by rmIFN gamma (100 U/mL) was corrected by mIFN gamma R-IgG in a dose-dependent manner, with an approximate IC50 of 0.05 nmol/L, and complete or near complete correction at 0.5 nmol/L. Similarly, a human IFN gamma R-IgG greatly reduced the inhibitory effect of recombinant human IFN gamma on human CFU-E. These experiments provide an in vitro animal model for studying the inhibitory effects of IFN gamma on erythropoiesis and indicate that IFN gamma R-IgG may be a useful agent for reducing the toxicity of IFN gamma in vivo.

scholarly journals Intestinal Adherence of Vibrio cholerae Involves a Coordinated Interaction between Colonization Factor GbpA and Mucin

2008 ◽  
Vol 76 (11) ◽  
pp. 4968-4977 ◽  
Author(s):  
Rudra Bhowmick ◽  
Abhisek Ghosal ◽  
Bhabatosh Das ◽  
Hemanta Koley ◽  
Dhira Rani Saha ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Nuclear Translocation ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Colonization Factor ◽  
Intestinal Mucus ◽  
Intestinal Mucin ◽  
Chitin Binding Protein ◽  
Dose Dependent

ABSTRACT The chitin-binding protein GbpA of Vibrio cholerae has been recently described as a common adherence factor for chitin and intestinal surface. Using an isogenic in-frame gbpA deletion mutant, we first show that V. cholerae O1 El Tor interacts with mouse intestinal mucus quickly, using GbpA in a specific manner. The gbpA mutant strain showed a significant decrease in intestinal adherence, leading to less colonization and fluid accumulation in a mouse in vivo model. Purified recombinant GbpA (rGbpA) specifically bound to N-acetyl-d-glucosamine residues of intestinal mucin in a dose-dependent, saturable manner with a dissociation constant of 11.2 μM. Histopathology results from infected mouse intestine indicated that GbpA binding resulted in a time-dependent increase in mucus secretion. We found that rGbpA increased the production of intestinal secretory mucins (MUC2, MUC3, and MUC5AC) in HT-29 cells through upregulation of corresponding genes. The upregulation of MUC2 and MUC5AC genes was dependent on NF-κB nuclear translocation. Interestingly, mucin could also increase GbpA expression in V. cholerae in a dose-dependent manner. Thus, we propose that there is a coordinated interaction between GbpA and mucin to upregulate each other in a cooperative manner, leading to increased levels of expression of both of these interactive factors and ultimately allowing successful intestinal colonization and pathogenesis by V. cholerae.

scholarly journals A Novel Mouse Model for Studying the Effects of Cyp17 Overexpression in a Temporal- and Spatial-Specific Manner

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A762-A763
Author(s):  
Christian Secchi ◽  
Martina Belli ◽  
Dwayne Stupack ◽  
Shunichi Shimasaki
Keyword(s):  
Mouse Model ◽  
Polycystic Ovary ◽  
Expression System ◽  
Follicular Development ◽  
In Vivo Model ◽  
Dependent Manner ◽  
Active Transcription ◽  
And Function ◽  
Dose Dependent

Abstract Background: Cyp17 plays a key role in theca cells (TCs) to produce androgens, which, in turn, are converted to estrogens in granulosa cells. Intrinsic alterations in ovarian steroidogenesis contribute to excessive ovarian androgen production that characterizes polycystic ovary disease (PCOS)1,2. Hyperandrogenism has been associated with higher levels of Cyp17 in TCs, and correlate with increased numbers of antral follicles3. While androgen excess is one of the hallmark features of PCOS, its putative role in the follicular development and function remains poorly known. Most efforts have used androgen administration or Cyp19 blockade approach to study how androgens prolong folliculogenesis4. Although some insights have been made, it is not clear if these models accurately address the cascade of effects that follow ovarian hyperandrogenism. Aim: Here, we aim to study the specific effects of hyperandrogenemia on ovarian morphology, follicle function and fertility with a new transgenic (TG) mouse model expressing elevated Cyp17 levels exclusively in TCs. Methods: We generated a breeding line of triple TG mice using a combination of the Tet-dependent expression system and the Cre/LoxP gene control system. Specifically, we used Cyp17 promoter-iCre mice crossed with trans-activator mice (R26-STOP-rtTA-IRES-EGFP transgene, Jackson Lab) and with a responder mouse carrying the TRE-Cyp17 transgene. Cyp17 promoter-iCre mice were used to ensure rtTA/EGFP is expressed specifically in TCs of secondary follicles. After the DNA segment between the two LoxP sites is excised by Cyp17iCre specifically in TCs, the R26-STOP-rtTA gene remains activated in all daughter TCs. Only upon treatment with Doxycycline (DOX) can suppression be relieved and active transcription of TRE-Cyp17 be induced in a dose-dependent manner. Results: Cyp17 mRNA expression levels in TCs of TG mice treated with 20, 100 or 200 mg/Kg DOX compared with corresponding untreated control mice showed a modulation in a dose-dependent manner (P=0.01 ANOVA). Confocal and RNAscope analysis validated (i) the effective combination of the Cyp17iCre/rtTA expression system visualizing the rtTA/EGFP specifically expressed in ovarian TCs and (ii) the DOX-induced increase of Cyp17 expression compared with the WT mice. DOX treated TG females were acyclic, being mostly arrested in diestrus. Analysis of estrous cycle stages revealed that treated TG females spent significantly more time in diestrus than control females (P=0.007, ANOVA). Conclusions: Our new in vivo model is the first that analyzes androgen impact independent of any extraovarian source of androgen, complementing current clinical efforts to study the occurrences of TCs elevated androgen levels in normal and PCOS women. 1 Rosenfield, R. L. et al. Endocr Rev (2016)2 Azziz, R. et al. Nat Rev Dis Primers (2016)3 Comim, F. V., et al. Hum Reprod (2013)4 Stener-Victorin, E. et al. Endocr Rev (2020)

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

scholarly journals Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xuxing Shen ◽  
Chao Wu ◽  
Meng Lei ◽  
Qing Yan ◽  
Haoyang Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Proteasome Inhibitor ◽  
Osteoclast Differentiation ◽  
Dependent Manner ◽  
Serum Enzyme ◽  
Herg Channels ◽  
Anti Tumor Activity ◽  
Dose Dependent

AbstractCarfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

scholarly journals Effect of Synchronous Versus Sequential Regimens on the Pharmacokinetics and Biodistribution of Regorafenib with Irradiation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 386
Author(s):  
Tung-Hu Tsai ◽  
Yu-Jen Chen ◽  
Li-Ying Wang ◽  
Chen-Hsi Hsieh
Keyword(s):  
Stereotactic Body Radiation Therapy ◽  
In Vivo Studies ◽  
Control Group ◽  
High Dose ◽  
Dependent Manner ◽  
Hep G2 ◽  
Time Curve ◽  
Dose Dependent

This study was performed to evaluate the interaction between conventional or high-dose radiotherapy (RT) and the pharmacokinetics (PK) of regorafenib in concurrent or sequential regimens for the treatment of hepatocellular carcinoma. Concurrent and sequential in vitro and in vivo studies of irradiation and regorafenib were designed. The interactions of RT and regorafenib in vitro were examined in the human hepatoma Huh-7, HA22T and Hep G2 cell lines. The RT–PK phenomenon and biodistribution of regorafenib under RT were confirmed in a free-moving rat model. Regorafenib inhibited the viability of Huh-7 cells in a dose-dependent manner. Apoptosis in Huh-7 cells was enhanced by RT followed by regorafenib treatment. In the concurrent regimen, RT decreased the area under the concentration versus time curve (AUC)regorafenib by 74% (p = 0.001) in the RT2 Gy × 3 fraction (f’x) group and by 69% (p = 0.001) in the RT9 Gy × 3 f’x group. The AUCregorafenib was increased by 182.8% (p = 0.011) in the sequential RT2Gy × 1 f’x group and by 213.2% (p = 0.016) in the sequential RT9Gy × 1 f’x group. Both concurrent regimens, RT2Gy × 3 f’x and RT9Gy × 3 f’x, clearly decreased the biodistribution of regorafenib in the heart, liver, lung, spleen and kidneys, compared to the control (regorafenib × 3 d) group. The concurrent regimens, both RT2Gy × 3 f’x and RT9Gy × 3 f’x, significantly decreased the biodistribution of regorafenib, compared with the control group. The PK of regorafenib can be modulated both by off-target irradiation and stereotactic body radiation therapy (SBRT).

Papaya shoot tip associated endophytic bacteria isolated from in vitro cultures and host–endophyte interaction in vitro and in vivo

2007 ◽  
Vol 53 (3) ◽  
pp. 380-390 ◽  
Author(s):  
Pious Thomas ◽  
Sima Kumari ◽  
Ganiga K. Swarna ◽  
T.K.S. Gowda
Keyword(s):  
Culture Medium ◽  
Carica Papaya ◽  
In Vitro Cultures ◽  
Dependent Manner ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Single Organism ◽  
Dose Dependent

Fourteen distinct bacterial clones were isolated from surface-sterilized shoot tips (~1 cm) of papaya (Carica papaya L. ‘Surya’) planted on Murashige and Skoog (MS)-based papaya culture medium (23/50 nos.) during the 2–4 week period following in vitro culturing. These isolates were ascribed to six Gram-negative genera, namely Pantoea ( P. ananatis ), Enterobacter ( E. cloacae ), Brevundimonas ( B. aurantiaca ), Sphingomonas , Methylobacterium ( M. rhodesianum ), and Agrobacterium ( A. tumefaciens ) or two Gram-positive genera, Microbacterium ( M. esteraromaticum ) and Bacillus ( B. benzoevorans ) based on 16S rDNA sequence analysis. Pantoea ananatis was the most frequently isolated organism (70% of the cultures) followed by B. benzoevorans (13%), while others were isolated from single stocks. Bacteria-harboring in vitro cultures often showed a single organism. Pantoea, Enterobacter, and Agrobacterium spp. grew actively on MS-based normal papaya medium, while Microbacterium, Brevundimonas, Bacillus, Sphingomonas, and Methylobacterium spp. failed to grow in the absence of host tissue. Supplying MS medium with tissue extract enhanced the growth of all the organisms in a dose-dependent manner, indicating reliance of the endophyte on its host. Inoculation of papaya seeds with the endophytes (20 h at OD550 = 0.5) led to delayed germination or slow seedling growth initially. However, the inhibition was overcome by 3 months and the seedlings inoculated with Pantoea, Microbacterium, or Sphingomonas spp. displayed significantly better root and shoot growths.

A dual approach to self-stimulation and locomotor trace affected by chronic methamphetamine treatment for an animal model of schizophrenia

1993 ◽  
Vol 71 (5-6) ◽  
pp. 321-325 ◽  
Author(s):  
Morikuni Takigawa ◽  
Hiroshi Maeda ◽  
Kenichi Ueyama ◽  
Hidefumi Tominaga ◽  
Kei Matsumoto
Keyword(s):  
Animal Model ◽  
Negative Symptoms ◽  
Disease Model ◽  
Stereotyped Behavior ◽  
Dependent Manner ◽  
Dual Approach ◽  
Reverse Tolerance ◽  
Self Stimulation ◽  
Dose Dependent

The effect of long-term methamphetamine (MAP) treatment on intracranial self-stimulation of the lateral hypotholamus and locomotor traces was assessed. An attempt was made to provide a useful animal model for understanding anhedonia, stereotypy, and reoccurrence of liability, which are analogous to symptoms of schizophrenia. The frequency of intracranial self-stimulation (ICSS) as used as a measure of the animals' "hedonic–anhedonic" state. Following long-term MAP treatment (3 mg/kg), rats gradually showed stereotyped behavior, and became inactive and unresponsive to ICSS. These behavioral changes and decreased ICSS lasted several weeks after cessation of chronic MAP treatment and seemed to suggest post-MAP chronic psychosis and (or) anhedonia, two of the negative symptoms of schizophrenia. The traces of rat behavior affected by chronic MAP treatment were classified into three types, peripheral, mixed, and fixed, occurring in a dose-dependent manner. Reverse tolerance, similar to the reoccurrence of schizophrenic symptoms, was observed as a fixed stereotypy associated with loss of ICSS. These abnormal phenomena were suppressed by pretreatment with haloperidol. In the present study, the combination of ICSS and locomotor trace affected by chronic MAP treatment was proposed as an animal model of schizophrenia and as a useful technique for gauging the effect of neuroleptics.Key words: self-stimulation, anhedonia, stereotypy, reverse tolerance, animal disease model, schizophrenia, methamphetamine.

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