In Vitro  and In Vivo  Effects of the Phosphodiesterase-III Inhibitor Enoximone on Malignant Hyperthermia–susceptible Swine

2003 ◽  
Vol 98 (4) ◽  
pp. 944-949 ◽  
Author(s):  
Marko Fiege ◽  
Frank Wappler ◽  
Ralf Weisshorn ◽  
Mark U. Gerbershagen ◽  
Kerstin Kolodzie ◽  
...  
Keyword(s):  
Malignant Hyperthermia ◽  
Cardiovascular Failure ◽  
In Vitro Contracture Test ◽  
Circulatory Insufficiency ◽  
Phosphodiesterase Iii Inhibitor ◽  
Genetically Determined ◽  
In Vivo Effects ◽  
Phosphodiesterase Iii

Background In human skeletal muscles, the phosphodiesterase-III inhibitor enoximone induces in vitro contracture development, and it has been suggested that enoximone could trigger malignant hyperthermia (MH). In this study, the in vitro and in vivo effects of enoximone in MH-normal (MHN) and MH-susceptible (MHS) swine were investigated. Methods Malignant hyperthermia trigger-free general anesthesia was performed in MHS and MHN swine. Skeletal muscle specimens were excised for an in vitro contracture test with 0.6 mm enoximone. Thereafter, MHS and MHN swine were exposed to cumulative administration of 0.5, 1, 2, 4, 8, 16, and 32 mg/kg enoximone intravenously. Clinical occurrence of MH was defined by a Pco(2) greater than 70 mmHg, a pH less than 7.20, and an increase in body temperature of more than 2.0 degrees C. Results Enoximone induced marked contractures in all MHS muscle specimens in vitro. In contrast, only small or no contracture development was observed in MHN muscle specimens, without an overlap in contractures between MHS and MHN muscles. However, in vivo, no clinical differences were found between MHS and MHN swine following cumulative enoximone doses. According to the defined criteria, none of the swine developed MH during the experiment. Furthermore, high enoximone doses induced progressive circulatory insufficiency, and after receiving 32 mg/kg enoximone, all animals died of cardiovascular failure. Conclusions The cumulative enoximone doses used in this study were 30- to 50-fold higher than therapeutic doses in humans. Enoximone does not trigger MH in genetically determined swine. However, enoximone might be useful for in vitro diagnosis of MH.

scholarly journals Effects of Theophylline on Anesthetized Malignant Hyperthermia-Susceptible Pigs

2011 ◽  
Vol 2011 ◽  
pp. 1-4
Author(s):  
Marko Fiege ◽  
Ralf Weisshorn ◽  
Kerstin Kolodzie ◽  
Frank Wappler ◽  
Mark U. Gerbershagen
Keyword(s):  
Malignant Hyperthermia ◽  
Body Core Temperature ◽  
Central Venous ◽  
Blood Concentrations ◽  
Malignant Hyperthermia Susceptible ◽  
Body Core ◽  
Genetically Determined ◽  
In Vivo Effects

Background. Theophylline was shown to induce contracture development in porcine malignant hyperthermia (MH) susceptible (MHS) skeletal muscles in vitro. The purpose of the current study was to investigate the in vivo effects of theophylline in MHS and MH normal (MHN) swine.Methods. MH-trigger-free general anesthesia was performed in MHS and MHN swine. Theophylline was administered intravenously in cumulative doses up to 93.5 mg⋅kg-1. The clinical occurrence of MH was defined by changes of central-venous pCO2, central-venous pH, and body core temperature.Results. Theophylline induced comparable clinical alterations in the anesthetized MHS and MHN swine, especially in regard to hemodynamic data. No pig developed hypermetabolism and/or MH according to defined criteria. All animals died with tachycardia followed by ventricular fibrillation.Conclusions. The cumulative theophylline doses used in this study were much higher than doses used therapeutically in humans, as demonstrated by measured blood concentrations. Theophylline is thus not a trigger of MH in genetically determined swine.

4-Chloro-m-cresol Triggers Malignant Hyperthermia in Susceptible Swine at Doses Greatly Exceeding Those Found in Drug Preparations

1999 ◽  
Vol 90 (6) ◽  
pp. 1723-1732. ◽  
Author(s):  
Paul A. Iaizzo ◽  
Brooks A. Johnson ◽  
Kaoru Nagao ◽  
William J. Gallagher
Keyword(s):  
Malignant Hyperthermia ◽  
Blood Chemistry ◽  
Response Curves ◽  
End Tidal ◽  
In Vivo Effects ◽  
Higher Doses ◽  
End Tidal Co2 ◽  
Cardiovascular Reactions

Background Chlorocresols are used as preservatives in numerous commercial drugs that have been shown to induce myoplasmic Ca2+ release; the most potent isoform is 4-chloro-m-cresol. The aims of this study were to (1) examine the in vivo effects of 4-chloro-m-cresol on swine susceptible to malignant hyperthermia and (2) contrast in vivo versus in vitro dose-response curves. Methods Susceptible swine (weight: 38.5 kg+/-3.55 kg) were anesthetized and monitored for variations in physiological responses, including end-tidal CO2, heart rate, blood pressure, blood chemistry, and temperatures. In the first animals studied, 4-chloro-m-cresol, at equivalent cumulative doses of 0.14, 0.28, 0.57, 1.14, 2.27, 4.54, and 9.08 mg/kg (n = 3; 12.5, 25, 50, 100, 200, 400, and 800 micromol) were administered, and in a second group, larger doses were used: 1.14, 3.41, 7.95, 17.04 (n = 4), and/or 35.22 (n = 1) mg/kg (100, 300, 700, 1,500, and/or 3,100 micromol). For comparison, in vitro rectus abdominis muscle preparations obtained from normal and susceptible swine were exposed to 4-chloro-m-cresol, at cumulative concentrations of 6.25, 12.5, 25, 50, 100, 200, 400, 800, and 1,600 micromol; standard caffeine and halothane contracture testing was also performed. Results Episodes of malignant hyperthermia were not triggered in response to administration of low doses of 4-chloro-m-cresol, but transient cardiovascular reactions (e.g., tachycardia, arrhythmias, and hypotension) were observed. Subsequently, episodes in these animals were triggered when halothane (0.87; 1 MAC) and succinylcholine (2 mg/kg) were given. Animals administered the higher doses of 4-chloro-m-cresol all had fulminant episodes of malignant hyperthermia that were fatal, when equivalent cumulative concentrations were greater than 1,500 micromol. The levels of 4-chloro-m-cresol in the plasma rapidly decreased: e.g., 5 min postadministration of the 1,500-micromol dose, the mean plasma level was only 52+/-18 micromol (n = 4). Hemolysis was detected following 4-chloro-m-cresol administration at concentrations > 200 micromol. In vitro, muscle from susceptible animals elicited contractures > 200 mg at 50-micromol bath concentrations of 4-chloro-m-cresol (n = 29), whereas normal muscle did not elicit such contractures until bath concentrations were > 800 micromol (n = 10). Conclusions 4-chloro-m-cresol is a trigger of malignant hyperthermia in susceptible swine, but only when serum concentrations are far above those likely to be encountered in humans. A relatively low concentration of 4-chloro-m-cresol, 50 micromol, is sufficient to activate sarcoplasmic [Ca+2] release in vitro (e.g., contractures); this same bolus dose administered in vivo (0.57 mg/kg) has minimal effects due to the rapid decrease in its plasma levels.

A364 DIAGNOSIS OF MALIGNANT HYPERTHERMIA BY IN VITRO CONTRACTURE TESTING WITH THE PHOSPHODIESTERASE-III-INHIBITOR ENOXIMONE

1997 ◽  
Vol 87 (Supplement) ◽  
pp. 364A
Author(s):  
M. Fiege ◽  
F. Wappler ◽  
V. von Richthofen ◽  
J. Scholz ◽  
J. Schulte Esch
Keyword(s):  
Malignant Hyperthermia ◽  
Phosphodiesterase Iii Inhibitor ◽  
Phosphodiesterase Iii

scholarly journals Propofol is a ‘Safe’ Anaesthetic Agent in Malignant Hyperthermia Susceptible Patients

1992 ◽  
Vol 20 (2) ◽  
pp. 165-168 ◽  
Author(s):  
A. J. McKenzie ◽  
K. G. Couchman ◽  
N. Pollock
Keyword(s):  
Literature Review ◽  
Malignant Hyperthermia ◽  
Muscle Biopsy ◽  
Anaesthetic Agent ◽  
Anaesthetic Technique ◽  
Malignant Hyperthermia Susceptible ◽  
Therapeutic Procedures ◽  
In Vivo Effects

In this study we investigated in vitro and in vivo effects of propofol in malignant hyperthermia susceptible (MHS) patients in order to assess the safety of propofol infusion as a non-triggering anaesthetic technique for diagnostic and therapeutic procedures. In vitro, human MHS muscle samples were exposed to propofol and changes in (a) baseline tension and (b) contracture tension on exposure to halothane and caffeine were measured. In vivo, (a) anaesthesia was induced in ten muscle biopsy positive MHS patients with propofol 2.5 mg/kg and (b) anaesthesia was produced in five muscle biopsy positive MHS patients with infusions of propofol up to 10 mg/kg/hr. In vitro, human MHS muscle did not develop contractures with propofol alone. Propofol had no significant effect on contracture development in response to halothane and caffeine. In vivo, no evidence of an MH response was detected following induction or maintenance of anaesthesia with propofol. Our results and literature review are in agreement that propofol is a ‘safe’ induction and maintenance agent in MHS patients. Propofol can be used for muscle biopsy anaesthesia because it does not alter the sensitivity of diagnostic muscle biopsy testing.

Pharmacology of 5-HT1A Receptors: Critical Aspects

CNS Spectrums ◽  
1998 ◽  
Vol 3 (10) ◽  
pp. 17-38 ◽  
Author(s):  
Franco Borsini
Keyword(s):  
Receptor Subtypes ◽  
Laboratory Conditions ◽  
In Vivo Effects ◽  
Critical Aspects

AbstractMyriad difficulties exist in analyzing the pharmacology of the serotonin 1A (5-HT1A) receptor. The receptor may demonstrate a different activity depending on the tissue or species used for analysis, the agent used, laboratory conditions, and differences between in vitro and in vivo effects of compounds. Affinity for 5-HT receptors also varies widely, presenting difficulties in drawing definitive conclusions on affinity values for various compounds. At least two possibilities exist to explain the diversity of pharmacology of 5-HT receptors. First, it is possible that different 5-HT1A receptor subtypes exist. Second, the 5-HT1A receptors may play a far more complex role than previously believed.

In vitro evaluation of estrogenic, antiestrogenic and antitumor effects of amentoflavone

2021 ◽  
pp. 096032712199945
Author(s):  
AT Aliyev ◽  
S Ozcan-Sezer ◽  
A Akdemir ◽  
H Gurer-Orhan
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Antitumor Effects ◽  
Antiestrogenic Activity ◽  
Er Positive ◽  
In Vivo Effects ◽  
Mcf 7

Apigenin, a flavonoid, is reported to act as an estrogen receptor (ER) agonist and inhibit aromatase enzyme. However, amentoflavone, a biflavonoid bearing two apigenin molecules, has not been evaluated for its endocrine modulatory effects. Besides, it is highly consumed by young people to build muscles, enhance mood and lose weight. In the present study, apigenin was used as a reference molecule and ER mediated as well as ER-independent estrogenic/antiestrogenic activity of amentoflavone was investigated. Antitumor activity of amentoflavone was also investigated in both ER positive (MCF-7 BUS) and triple-negative (MDA-MB-231) breast cancer cells and its cytotoxicity was evaluated in human breast epithelial cells (MCF-10A). Our data confirmed ER agonist, aromatase inhibitory and cytotoxic effects of apigenin in breast cancer cells, where no ER mediated estrogenic effect and physiologically irrelevant, slight, aromatase inhibition was found for amentoflavone. Although selective cytotoxicity of amentoflavone was found in MCF-7 BUS cells, it does not seem to be an alternative to the present cytotoxic drugs. Therefore, neither an adverse effect, mediated by an estrogenic/antiestrogenic effect of amentoflavone nor a therapeutical benefit would be expected from amentoflavone. Further studies could be performed to investigate its in vivo effects.

scholarly journals Effects of Bacterial CLPB Protein Fragments on Food Intake and PYY Secretion

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2223
Author(s):  
Manon Dominique ◽  
Nicolas Lucas ◽  
Romain Legrand ◽  
Illona-Marie Bouleté ◽  
Christine Bôle-Feysot ◽  
...  
Keyword(s):  
Food Intake ◽  
Peptide Yy ◽  
Molecular Mimicry ◽  
Potential Effect ◽  
In Vivo Studies ◽  
Sprague Dawley ◽  
E Coli ◽  
In Vivo Effects

CLPB (Caseinolytic peptidase B) protein is a conformational mimetic of α-MSH, an anorectic hormone. Previous in vivo studies have already shown the potential effect of CLPB protein on food intake and on the production of peptide YY (PYY) by injection of E. coli wild type (WT) or E. coli ΔClpB. However, until now, no study has shown its direct effect on food intake. Furthermore, this protein can fragment naturally. Therefore, the aim of this study was (i) to evaluate the in vitro effects of CLPB fragments on PYY production; and (ii) to test the in vivo effects of a CLPB fragment sharing molecular mimicry with α-MSH (CLPB25) compared to natural fragments of the CLPB protein (CLPB96). To do that, a primary culture of intestinal mucosal cells from male Sprague–Dawley rats was incubated with proteins extracted from E. coli WT and ΔCLPB after fragmentation with trypsin or after a heat treatment of the CLPB protein. PYY secretion was measured by ELISA. CLPB fragments were analyzed by Western Blot using anti-α-MSH antibodies. In vivo effects of the CLPB protein on food intake were evaluated by intraperitoneal injections in male C57Bl/6 and ob/ob mice using the BioDAQ® system. The natural CLPB96 fragmentation increased PYY production in vitro and significantly decreased cumulative food intake from 2 h in C57Bl/6 and ob/ob mice on the contrary to CLPB25. Therefore, the anorexigenic effect of CLPB is likely the consequence of enhanced PYY secretion.

scholarly journals Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

2021 ◽  
Vol 22 (3) ◽  
pp. 1347
Author(s):  
Anaïs Amend ◽  
Natalie Wickli ◽  
Anna-Lena Schäfer ◽  
Dalina T. L. Sprenger ◽  
Rudolf A. Manz ◽  
...  
Keyword(s):  
B Cell ◽  
Disease Model ◽  
Interleukin 10 ◽  
Immune Functions ◽  
Murine Lupus ◽  
Anti Inflammatory ◽  
In Vivo Effects

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

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