Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin

2002 ◽  
Vol 282 (6) ◽  
pp. R1636-R1642 ◽  
Author(s):  
Alan Wells ◽  
W. Gary Anderson ◽  
Neil Hazon
Keyword(s):  
Plasma Osmolality ◽  
Arginine Vasotocin ◽  
Scyliorhinus Canicula ◽  
Perfusate Flow ◽  
Elasmobranch Fish ◽  
Tubular Transport ◽  
Perfused Kidney

Acclimation of the European lesser-spotted dogfish Scyliorhinus canicula to reduced environmental salinity [85–70% seawater (SW)] induced a significant diuresis in addition to a significant decrease in plasma osmolality in vivo. The threshold for this diuresis was determined to be 85% SW. Therefore, S. canicula acclimated to 85% SW was selected for further study as a diuretic model in the development of an in situ perfused kidney preparation. The renal role of arginine vasotocin (AVT) in the in situ perfused trunk preparation was investigated. In SW, perfusion of 10−9 and 10−10 M AVT resulted in a glomerular antidiuresis and decreases in tubular transport maxima for glucose and perfusate flow. In 85% SW, 10−10 M AVT had no significant effect on these renal parameters with the exception of transport maxima for glucose and perfusate flow. Tubular parameters remained unchanged by either 10−9 or 10−10 M AVT. The results demonstrate that the perfused kidney preparation was a viable tool for the investigation of renal parameters in elasmobranch fish and that AVT induced a glomerular antidiuresis.

Nitric oxide modulates hepatic vascular tone in normal rat liver

1994 ◽  
Vol 267 (3) ◽  
pp. G416-G422 ◽  
Author(s):  
M. K. Mittal ◽  
T. K. Gupta ◽  
F. Y. Lee ◽  
C. C. Sieber ◽  
R. J. Groszmann
Keyword(s):  
Nitric Oxide ◽  
Vascular Tone ◽  
Portal Pressure ◽  
Portal Circulation ◽  
Perfusate Flow ◽  
Normal Rat ◽  
Rat Livers

This study investigated whether nitric oxide (NO) plays a role in the intrahepatic portal circulation in normal rat livers perfused in situ. N omega-nitro-L-arginine (NNA), a specific NO biosynthesis inhibitor, significantly increased baseline portal pressure compared with controls (P < 0.05). Concentration-effect curves to norepinephrine (NE) were performed. Perfusate flow was maintained as constant, and perfusion pressure was continuously measured. NNA markedly enhanced the responsiveness to NE. This effect was abolished by the addition of L-arginine, a specific NO substrate. Presence of indomethacin did not alter the response to NE. The response to NE in the presence of indomethacin and NNA was significantly more than the response to NE in the presence of NNA alone. In vivo, intraportal infusion of NNA significantly enhanced the portal pressure compared with vehicle. This study demonstrates that NO contributes to the basal vascular tone and attenuates the response to NE in intrahepatic portal vascular bed of normal rats. These results support a functional role of NO in the regulation of the intrahepatic portal circulation in normal rats. This study also suggests a synergistic, albeit limited, role of prostacyclin in the intrahepatic circulation.

Glomerular actions of arginine vasotocin in the in situ perfused trout kidney

1995 ◽  
Vol 269 (4) ◽  
pp. R775-R780 ◽  
Author(s):  
S. Amer ◽  
J. A. Brown
Keyword(s):  
Free Water ◽  
Aortic Pressure ◽  
Arginine Vasotocin ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Perfusate Flow ◽  
Plasma Arginine ◽  
Dose Dependent

Recent measurements of plasma arginine vasotocin (AVT) in teleost fish suggest circulating concentrations of 10(-10)-10(-12)M. Previous studies of the renal actions of AVT in vivo suggest both diuretic and antidiuretic effects, but at unknown circulating concentrations. We have investigated the renal actions of 10(-9) and 10(-11) M AVT in vitro using an in situ perfused kidney preparation of rainbow trout (oncorhynchus mykiss). AVT increased vascular resistance (56%), reduced perfusate flow (P < 0.001), and increased interrenal aortic pressure (P < 0.001). AVT resulted in dose-dependent decreases in urine flow rates, glomerular filtration rates, and tubular transport maxima for glucose. AVT at 10(-11) M reduced relative free water clearances (P < 0.01), but urine/plasma inulin ratios were unchanged, whereas 10(-9)M AVT reduced urine/plasma inulin ratios (P < 0.01) and increased relative free water clearances (P < 0.05). The filtering population of glomeruli was reduced by both 10(-11) and 10(-9)M AVT to approximately one-third of the glomeruli, and a similar population of arterially perfused but nonfiltering glomeruli emerged. These results demonstrate that physiological concentrations of AVT have potent glomerular antidiuretic action in the trout, reducing the number of functional glomeruli, and imply reduced individual nephron filtration rates.

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

Osmotic and volaemic effects on drinking rate in elasmobranch fish

2002 ◽  
Vol 205 (8) ◽  
pp. 1115-1122 ◽  
Author(s):  
W. Gary Anderson ◽  
Y. Takei ◽  
N. Hazon
Keyword(s):  
Sea Water ◽  
Plasma Osmolality ◽  
Fold Increase ◽  
Total Blood Volume ◽  
Elevated Plasma ◽  
Total Blood ◽  
Drinking Rate ◽  
Scyliorhinus Canicula ◽  
Drinking Response ◽  
Elasmobranch Fish

SUMMARYAn increase in drinking rate of two species of marine elasmobranch fish, Scyliorhinus canicula and Triakis scyllia, acclimated to 80% sea water was observed following the introduction of 100 % sea water to experimental tanks. The drinking response in both species was found to be maximal within 6 h, and a significant increase was sustained for up to 24 h in T. scyllia. Plasma osmolality was significantly increased within 6 h following introduction of 100 % sea water, and this increase was principally due to elevated plasma Na+ and Cl- concentrations. Administration of 2 mol l-1 mannitol, 75 % sucrose and vehicle(elasmobranch Ringer) did not induce a significant increase or decrease in the drinking rate of S. canicula. However, injection of 20 % NaCl was found to decrease drinking rate significantly in S. canicula 60 min after administration. Controlled haemorrhage of approximately 5.7 % of total blood volume in S. canicula induced a rapid 36-fold increase in drinking over basal levels. The present study demonstrates a physiological dipsogenesis in response to hypovolaemia in marine elasmobranch fish as part of their overall iso/hyperosmoregulatory strategy.

Carbonic anhydrase in the midgut of larvalAedes aegypti: cloning, localization and inhibition

2002 ◽  
Vol 205 (5) ◽  
pp. 591-602 ◽  
Author(s):  
Maria del Pilar Corena ◽  
Theresa J. Seron ◽  
Herm K. Lehman ◽  
Judith D. Ochrietor ◽  
Andrea Kohn ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Aedes Aegypti ◽  
Fruit Fly ◽  
Cellular Heterogeneity ◽  
Carbonic Anhydrases ◽  
Larval Midgut ◽  
Posterior Midgut

SUMMARYThe larval mosquito midgut exhibits one of the highest pH values known in a biological system. While the pH inside the posterior midgut and gastric caeca ranges between 7.0 and 8.0, the pH inside the anterior midgut is close to 11.0. Alkalization is likely to involve bicarbonate/carbonate ions. These ions are produced in vivo by the enzymatic action of carbonic anhydrase. The purpose of this study was to investigate the role of this enzyme in the alkalization mechanism, to establish its presence and localization in the midgut of larval Aedes aegypti and to clone and characterize its cDNA. Here, we report the physiological demonstration of the involvement of carbonic anhydrase in midgut alkalization. Histochemistry and in situ hybridization showed that the enzyme appears to be localized throughout the midgut, although preferentially in the gastric caeca and posterior regions with specific cellular heterogeneity. Furthermore, we report the cloning and localization of the first carbonic anhydrase from mosquito larval midgut. A cDNA clone from Aedes aegypti larval midgut revealed sequence homology to α-carbonic anhydrases from vertebrates. Bioinformatics indicates the presence of at least six carbonic anhydrases or closely related genes in the genome of another dipteran, the fruit fly Drosophila melanogaster. Molecular analyses suggest that the larval mosquito may also possess multiple forms.

scholarly journals AL355338 acts as an oncogenic lncRNA by interacting with protein ENO1 to regulate EGFR/AKT pathway in NSCLC

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qian Hua ◽  
Dongliang Wang ◽  
Lin Zhao ◽  
Zhihui Hong ◽  
Kairu Ni ◽  
...  
Keyword(s):  
Aerobic Glycolysis ◽  
Transcript Abundance ◽  
Metabolic Reprogramming ◽  
Clinical Samples ◽  
Abnormal Metabolism ◽  
Considerable Morbidity

Abstract Background Non-small cell lung cancer (NSCLC) is a malignancy with considerable morbidity and mortality. Abnormal metabolism is a hallmark of cancer; however, the mechanism of glycolysis regulation in NSCLC progression is not completely understood. Recent studies suggest that some dysregulated long non-coding RNAs (lncRNAs) play important roles in tumor metabolic reprogramming. Methods To identify glycolysis-associated-lncRNAs in NSCLC, we compared RNA-sequencing results between high 18F-fluorodeoxyglucose (FDG)-uptake NSCLC tissues and paired paratumor tissues. The transcript abundance of AL355338 in 80 pairs of clinical samples was evaluated by quantitative real-time PCR assay and fluorescence in situ hybridization. The biological role of AL355338 on NSCLC cells were evaluated by functional experiments in vitro and in vivo. Moreover, RNA pull-down, mass spectrometry and RNA immunoprecipitation (RIP) assays were used to identify the protein interacted with AL355338. Co-immunoprecipitation, in situ proximity ligation assays and western blotting were applied to define the potential downstream pathways of AL355338. Results AL355338 was an upregulated glycolysis-associated lncRNA in NSCLC. Functional assays revealed that AL355338 was critical for promoting aerobic glycolysis and NSCLC progression. Mechanistic investigations showed that AL355338 directly bound with alpha-enolase (ENO1) and enhanced the protein’s stability by modulating its degradation and ubiquitination. A positive correlation was observed between AL355338 and ENO1 in NSCLC, and ENO1 was subsequently confirmed to be responsible for the oncogenic role of AL355338. Furthermore, AL355338 was capable of modulating ENO1/EGFR complex interaction and further activating EGFR-AKT signaling. Conclusions This study indicates that AL355338 confers an aggressive phenotype to NSCLC, and targeting it might be an effective therapeutic strategy.

scholarly journals LncRNA-URHC Functions as a ceRNA to Regulate Danjb9 Expression by Competitively Binding to miR-5007-3p in Hepatocellular Carcinoma

2021 ◽  
Author(s):  
kunwei niu ◽  
Shibin Qu ◽  
Xuan Zhang ◽  
Jimin Dai ◽  
Jianlin Wang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Biological Effects ◽  
Luciferase Reporter ◽  
Underlying Mechanisms ◽  
Proliferation In Vitro ◽  
Hcc Cells

Abstract Background: Hepatocellular carcinoma (HCC) is often diagnosed at a late stage, when the prognosis is poor. The regulation of long non-coding RNAs (lncRNAs) plays a crucial role in HCC. However, the precise regulatory mechanisms of lncRNA signaling in HCC remain largely unknown. We study aim to investigate the underlying mechanisms of lncRNA (upregulated in hepatocellular carcinoma) URHC in HCC. Methods: RT-qPCR, fluorescence in situ hybridization (FISH) staining, EdU, colony formation, and tumor xenografts experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The bioinformatics analysis, Dual-luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC.Results: URHC silencing may inhibit the HCC cells proliferation in vitro and in vivo. We found that URHC was mainly localized in the cytoplasm. The expression of miR-5007-3p was negatively regulated by URHC. And miR-5007-3p could reverse the effect of URHC in HCC cells. The expression of DNAJB9 was negatively regulated by miR-5007-3p but positively regulated by URHC. These suggesting of lncRNA-URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p.Conclusion: Together, our study elucidated the role of URHC as a miRNA sponge in HCC, and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.

scholarly journals Cortisol and Dexamethasone Mediate Glucocorticoid Actions in the Lesser Spotted Catshark (Scyliorhinus canicula)

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 56
Author(s):  
Juncal Cabrera-Busto ◽  
Juan M. Mancera ◽  
Ignacio Ruiz-Jarabo
Keyword(s):  
White Muscle ◽  
Ex Vivo ◽  
Response Curves ◽  
Scyliorhinus Canicula ◽  
Energy Stores ◽  
Specific Receptors ◽  
Muscle Energy ◽  
Ex Vivo Culture

Corticosteroids are hormones produced in vertebrates exerting gluco- and mineralocorticoid actions (GC and MC) mediated by specific receptors (GR and MR, respectively). In elasmobranchs, the major circulating corticosteroid is the 1α-hydroxycorticosterone (1α-OHB). This hormone acts as a MC, but to date its role as a GC has not been established. As there is no 1α-OHB standard available, here we employed a set of in vivo and ex vivo approaches to test GC actions of other corticosteroids in the lesser spotted catshark (Scyliorhinus canicula). Dexamethasone (DEX, a synthetic corticosteroid) slow-release implants decreased plasma 1α-OHB levels after 7 days, and modified carbohydrates metabolism in liver and white muscle (energy stores and metabolic enzymes). In addition, ex vivo culture of liver and white muscle explants confirmed GC actions of corticosteroids not naturally present in sharks (cortisol and DEX) by increasing glucose secretion from these tissues. Dose–response curves induced by cortisol and DEX, altogether with the use of specific GR inhibitor mifepristone, confirmed the involvement of GR mediating glucose secretion. This study highlights the influence of corticosteroids in the glucose balance of S. canicula, though the role of 1α-OHB as a GC hormone in sharks should be further confirmed.

Cytoarchitecture of the Xenopus thymus following gamma-irradiation

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 95-105
Author(s):  
JH Russ ◽  
JD Horton
Keyword(s):  
Gamma Irradiation ◽  
Tolerance Induction ◽  
Cell Types ◽  
Whole Body ◽  
Thymic Stromal Cells ◽  
Normal Architecture

This paper describes in vitro and in vivo attempts to deplete the 4- to 8-month-old Xenopus laevis (J strain) thymus of its lymphocyte compartment. Gamma irradiation (2-3000 rad) of the excised thymus, followed by two weeks in organ culture, is effective in removing lymphocytes, but causes drastic reduction in size and loss of normal architecture. In contrast, in vivo whole-body irradiation (3000 rad) and subsequent in situ residence for 8-14 days proves successful in providing a lymphocyte-depleted froglet thymus without loss of cortical and medullary zones. In vivo-irradiated thymuses are about half normal size, lack cortical lymphocytes, but still retain some medullary thymocytes; they show no signs of lymphocyte regeneration when subsequently organ cultured for 2 weeks. Light microscopy of 1 micron, plastic-embedded sections and electron microscopy reveal that a range of thymic stromal cell types are retained and that increased numbers of cysts, mucous and myoid cells are found in the thymus following whole-body irradiation. In vivo-irradiated thymuses are therefore suitable for implantation studies exploring the role of thymic stromal cells in tolerance induction of differentiating T lymphocytes.

The role of 20-hydroxyecdysone in stimulating epidermal mitoses during the laval-pupal transformation of the tobacco hornworm, Manduca sexta

Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Y. Kato ◽  
L.M. Riddiford
Keyword(s):  
Mitotic Index ◽  
Manduca Sexta ◽  
Ploidy Level ◽  
Polyploid Cells ◽  
Mitotic Frequency ◽  
Mitotic Figures ◽  
Dorsal Epidermis

Temporal and regional changes in mitotic frequency were examined in the dorsal epidermis of the fourth and fifth abdominal segments of Manduca sexta during metamorphosis. Mitoses occurred only in the middle intrasegmental region, but not in the segmental margins. The mitoses began early on day 5 and rose to maximum of 2á6–4á6% about 10h later. When the integument from day 4 (wandering) larvae was cultured in Grace's medium containing 0.3 to 1μgml-1 20-hydroxyecdysone (20HE), the mitotic index increased with a peak at 18–24h exposure approximately equal to that found in situ. The level of 20HE required to initiate mitoses was similar to that found in vivo during the beginning of the prepupal rise in ecdysteroid and therefore is likely to be the signal for these cells to decrease their ploidy level of 4–32C to 2–8C at this time. The polyploid cells had larger mitotic figures and required a longer exposure to 20-hydroxyecdysone to initiate mitosis. Some multipolar mitotic figures were observed.

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