scholarly journals Crustacean cardioexcitatory peptides may inhibit the heart in vivo.

1995 ◽  
Vol 198 (12) ◽  
pp. 2547-2550 ◽  
Author(s):  
I J McGaw ◽  
J L Wilkens ◽  
B R McMahon ◽  
C N Airriess
Keyword(s):  
Stroke Volume ◽  
Isolated Heart ◽  
Cancer Magister ◽  
Isolated Hearts ◽  
Cardiovascular Performance ◽  
Cast Doubt ◽  
Cardiac Stroke Volume

Peptide neurohormones exist as functionally similar analogues in a wide variety of invertebrate and vertebrate phyla, and many have been implicated as cardiovascular regulators. In decapod crustaceans, these include the pentapeptide proctolin, crustacean cardioactive peptide (CCAP) and the FMRF amide-related peptides F1 and F2, all of which are found in the pericardial organs located immediately upstream of the heart. Cardioexcitatory activity has been demonstrated by these four peptides in both isolated and semi-isolated arthropod hearts; CCAP, however, has minimal effects on the heart of Cancer magister. In the present study, we determined the effects of proctolin, F1 and F2 on the heart of the crab C. magister in both in vitro (semi-isolated heart) and in vivo (whole animal) preparations. In semi-isolated hearts, infusion of each peptide caused cardioexcitation, increasing the rate and stroke volume of the heart. In whole crabs, the peptides were cardioinhibitory; the strongest effects were observed with F1 and F2, which dramatically decreased heart rate, cardiac stroke volume and cardiac output. These results cast doubt on current perceptions of the functional role of cardioactive peptides in the regulation of invertebrate cardiovascular performance in vivo.

scholarly journals OXYGEN SUPPLY AND IN VITRO PERFORMANCE OF THE SYSTEMIC HEART OF OCTOPUS VULGARIS: EFFECTS OF HAEMOCYANIN

1991 ◽  
Vol 157 (1) ◽  
pp. 523-540 ◽  
Author(s):  
C. AGNISOLA ◽  
D. F. HOULIHAN
Keyword(s):  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Supply ◽  
Sea Water ◽  
Isolated Heart ◽  
Carbon Dioxide Production ◽  
Octopus Vulgaris ◽  
Systemic Heart

The effect of increasing oxygen supply on the perfused systemic heart of Octopus vulgaris (Lam.) by using oxygenated or haemocyanin-containing perfusates was investigated. Providing aerated blood or seawater solutions of haemocyanin that were comparable with blood in oxygen-carrying capacity improved the performance of the isolated heart compared with that of hearts perfused with aerated sea water. Aortic outputs were similar to in vivo values (44ml min−1 g−1) at close to in vivo values of preload and afterload owing to an increase in both heart rate (from 24.0 to 38.4beatsmin−1) and stroke volume (from 0.69 to 1.10ml g−1). Coronary flow fell in these conditions, becoming 2.5% of the aortic output (against 24% with aerated sea water). A parallel increase in coronary resistance was found. Oxygenated sea water also improved the performance of the heart, mainly by improving the stroke volume. Both with haemocyanin solutions or blood and with oxygenated sea water, the isolated heart was able to do more work at lower preloads compared with the hearts perfused with aerated sea water. Power output was linearly related to total oxygen consumption and carbon dioxide production. The major site of oxygen consumption was the coronary bed. Haemocyanin released about 70% of the bound oxygen as it passed through the ventricular wall. Note: Present address: Department of Zoology, University of Aberdeen, Aberdeen AB9 2TN, Scotland, UK.

Experiments with the Isolated Heart of the Gastropod Helix Pomatia in an Artificial Pericardium

1972 ◽  
Vol 56 (1) ◽  
pp. 239-247
Author(s):  
G. W. CIVIL ◽  
T. E. THOMPSON
Keyword(s):  
Venous Return ◽  
Isolated Heart ◽  
Helix Pomatia ◽  
Physiological Saline ◽  
Heart Beat ◽  
Pericardial Fluid ◽  
Isolated Hearts ◽  
Opening Up

1. Isolated hearts of Helix pomatia could be maintained for 3-4 days at 19 °C in physiological saline. Co-ordination was soon lost, but irregular twitches could be observed for up to 115 h. 2. A perfusion apparatus was designed which supplied a simulated venous return pressure of 8 cm saline and enabled in vitro survival of pericardium-free hearts for up to 2 days at 15 °C. Cessation of perfusion led immediately to a reversible stoppage of heart-beat. 3. An artificial pericardium apparatus (APA) allowed the role of the pericardium to be studied. In the APA measurable translocation of fluid was effected by the heart, even when the simulated venous return pressure was negative. 4. If the APA was transformed into an open system by opening up a simulated reno-pericardial canal, the effectiveness of the heart was greatly reduced. 5. In the APA the greater the dilation of the heart (in consequence of decreased volume of pericardial fluid) the greater was the stroke volume for a given simulated venous return pressure. 6. Results obtained with the APA give support to the theory that in the gastropod heart the filling of the auricle is hydrodynamically coupled (through the pericardial fluid) to the emptying of the ventricle.

Effect of phenolphthalein on monkey intestinal water and electrolyte transport

1982 ◽  
Vol 243 (4) ◽  
pp. G268-G275
Author(s):  
D. W. Powell ◽  
P. T. Johnson ◽  
J. C. Bryson ◽  
R. C. Orlando ◽  
C. C. Fan
Keyword(s):  
Ussing Chamber ◽  
Test Tube ◽  
Prostaglandin Synthesis ◽  
Electrolyte Transport ◽  
Inhibit Prostaglandin Synthesis ◽  
Cast Doubt ◽  
Synthesis Stimulation

To assess Na-K-ATPase inhibiton and prostaglandin synthesis stimulation as the mechanism of the secretory (cathartic) action of phenolphthalein in the primate, we investigated water and electrolyte transport and Na-K-ATPase levels in monkey intestine. Both jejunum and colon were studied with in vivo perfusion and in vitro Ussing chamber techniques. Water, Na, and Cl absorption was inhibited or secretion was induced by phenolphthalein (10(-3) M) in the jejunum and colon when the drug was present in the mucosal bathing (perfusion) solution. Serosal addition of phenolphthalein (10(-4) or 10(-3) M) induced Na and anion absorption in the jejunum but not in the colon. Phenolphthalein inhibited Na-K-ATPase activity in the test tube, but assays of intestine previously perfused or bathed in the drug showed no inhibiton. Indomethacin, in doses sufficient to inhibit prostaglandin synthesis in the intestine, inhibited the secretion induced by phenolphthalein in the jejunum but not in the colon. These inconsistencies cast doubt on the role of Na-K-ATPase inhibition or the role of prostaglandin synthesis stimulation in the mechanism of action of phenolphthalein.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Anti-obesity role of Aster glehni extract: in vivo and in vitro effects

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
HM Lee ◽  
TG Ahn ◽  
CW Kim ◽  
HJ An
Keyword(s):  
In Vitro Effects

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

THYROID STIMULATORS AND THYROID STIMULATION

1971 ◽  
Vol 66 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Gerald Burke
Keyword(s):  
Regulatory System ◽  
Control Site ◽  
Thyroid Cell ◽  
Primary Control ◽  
Physico Chemical ◽  
Site Of Action ◽  
Long Acting

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.

THE ROLE OF POLYETHYLENIMINE IN ENHANCING PERFORMANCE OF GLUTAMATE BIOSENSORS

2018 ◽  
Vol 8 (3) ◽  
pp. 36-41
Author(s):  
Diep Do Thi Hong ◽  
Duong Le Phuoc ◽  
Hoai Nguyen Thi ◽  
Serra Pier Andrea ◽  
Rocchitta Gaia
Keyword(s):  
First Generation ◽  
Good Reproducibility ◽  
Complex Matrices ◽  
Long Term Stability ◽  
In Vitro Characterization ◽  
Glutamate Oxidase

Background: The first biosensor was constructed more than fifty years ago. It was composed of the biorecognition element and transducer. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples Glutamate is important biochemicals involved in energetic metabolism and neurotransmission. Therefore, biosensors requires the development a new approach exhibiting high sensibility, good reproducibility and longterm stability. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples. The aims of this work: To find out which concentration of polyethylenimine (PEI) exhibiting the most high sensibility, good reproducibility and long-term stability. Methods: We designed and developed glutamate biosensor using different concentration of PEI ranging from 0% to 5% at Day 1 and Day 8. Results: After Glutamate biosensors in-vitro characterization, several PEI concentrations, ranging from 0.5% to 1% seem to be the best in terms of VMAX, the KM; while PEI content ranging from 0.5% to 1% resulted stable, PEI 1% displayed an excellent stability. Conclusions: In the result, PEI 1% perfomed high sensibility, good stability and blocking interference. Furthermore, we expect to develop and characterize an implantable biosensor capable of detecting glutamate, glucose in vivo. Key words: Glutamate biosensors, PEi (Polyethylenimine) enhances glutamate oxidase, glutamate oxidase biosensors

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