Chloride self-exchange in toad skeletal muscle in vivo and in vitro

1982 ◽  
Vol 242 (3) ◽  
pp. C207-C217 ◽  
Author(s):  
D. D. Macchia
Keyword(s):  
Muscle Cells ◽  
Ringer Solution ◽  
Resting Potential ◽  
Electrochemical Gradient ◽  
Hindlimb Muscles ◽  
A Value ◽  
Hindlimb Muscle ◽  
The Mean

The exchange of cellular Cl with 36Cl has been measured in saline-perfused hindlimb muscles of the pithed toad and compared with cellular Cl exchange in isolated muscles incubated in the vitro either in toad Ringer solution or in toad plasma. In the perfused hindlimb, the rate of 36Cl efflux from muscle cells [17.0 +/- 0.9 pmol Cl.(cm2 plasma membrane.s)-1] was only 40% as fast as that of the 36Cl influx. The discrepancy between Cl influx and efflux was accompanied by a cellular accumulation of Cl against the electrochemical gradient for this anion. Concurrently, the cells took up Na in amounts at least equal to the accumulated Cl. During this accumulation of Na and Cl, the mean resting potential remained constant at a value of -89.2 +/- 1.9 (SE) mV. Na and Cl were taken up by the muscle cells of the perfused hindlimb without a concomitant decrease in cellular K content; i.e., without evidence of inhibition of the Na-K pump. The rate constant for cellular 36Cl efflux from isolated toad muscles preincubated for 3 h in vitro in toad Ringer solution was about five times faster than that of muscles in the perfused hindlimb and similar in magnitude to published values for Cl fluxes in frog muscle. Cellular Cl efflux from muscles briefly preincubated in vitro for 15 min instead of 3 h was significantly slower than after prolonged preincubation. In vitro incubation of isolated toad muscles in toad plasma slowed the cellular 36Cl efflux to values approaching those measured in the perfused hindlimb, without comparably depressing the 36Cl influx. It is suggested that the uptake of NaCl by the cells of perfused hindlimb muscle may proceed by an electroneutral inward cotransport of Na and Cl on the same carrier.

Glycogenolysis in the Liver of the Common Frog, Rana Temporaria

1956 ◽  
Vol 33 (1) ◽  
pp. 196-210
Author(s):  
J. S. TINDAL
Keyword(s):  
Rana Temporaria ◽  
Complex Form ◽  
Glucose Production ◽  
Liver Glycogen ◽  
Ringer Solution ◽  
Type B ◽  
Liver Slices ◽  
The Mean

1. The form of the temperature-glycogenolysis curve of frog's liver slices, when incubated with Ringer solution, was determined over the range 7-21° C. for samples of frogs over a period of 18 months. Three types of curve were observed: (a) Low linear, interpreted as being the least complex form, in which the action of temperature is not complicated by other factors. (b) Type B, which showed a disproportionate increase in glucose production above a certain temperature, attributed to the potentiation of sympathomimetic material. (c) High linear. 2. Both the addition of adrenaline and noradrenaline to the incubation medium caused an increase in glucose production at all temperatures. Also, the disproportionate increase in glucose production of the type B curve occurred at a lower temperature in the presence of either of these agents. 3. Thyroxine had no effect on the form of the temperature-glycogenolysis curve, and there was no correlation between the state of activity of the thyroid gland and the type of temperature-glycogenolysis curve. 4. Glucose production of liver slices was lowered at all temperatures by the in vivo administration of insulin 19 hr. prior to an experiment. Insulin in vitro had no action. 5. Dibenzyline lowered glucose production of liver slices at all temperatures, and raised the temperature at which the extra glucose production, associated with a type B curve, occurred. The extrapolation of the lower portion of the mean curve after dibenzyline to 21° C. gave a line almost identical with the mean low linear curve. 6. The environmental temperature at which frogs were maintained prior to an experiment did not affect the form of the temperature-glycogenolysis curve. 7. The seasonal variation in liver-glycogen content was found to agree closely with the values obtained by Smith (1950).

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

scholarly journals Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein
Keyword(s):  
Theoretical Model ◽  
Castor Oil ◽  
In Vivo Studies ◽  
Coating Materials ◽  
Peg 400 ◽  
The Mean ◽  
Usp Apparatus ◽  
Solid System

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

scholarly journals Characterization of the SARS-CoV-2 coronavirus X4-like accessory protein

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Olanrewaju Ayodeji Durojaye ◽  
Nkwachukwu Oziamara Okoro ◽  
Arome Solomon Odiba
Keyword(s):  
Rapid Development ◽  
Protein A ◽  
The Novel ◽  
Quality Model ◽  
A Value ◽  
Model Protein ◽  
Novel Coronavirus ◽  
Global Threat

Abstract Background The novel coronavirus SARS-CoV-2 is currently a global threat to health and economies. Therapeutics and vaccines are in rapid development; however, none of these therapeutics are considered as absolute cure, and the potential to mutate makes it necessary to find therapeutics that target a highly conserved regions of the viral structure. Results In this study, we characterized an essential but poorly understood coronavirus accessory X4 protein, a core and stable component of the SARS-CoV family. Sequence analysis shows a conserved ~ 90% identity between the SARS-CoV-2 and previously characterized X4 protein in the database. QMEAN Z score of the model protein shows a value of around 0.5, within the acceptable range 0–1. A MolProbity score of 2.96 was obtained for the model protein and indicates a good quality model. The model has Ramachandran values of φ = − 57o and ψ = − 47o for α-helices and values of φ = − 130o and ψ = + 140o for twisted sheets. Conclusions The protein data obtained from this study provides robust information for further in vitro and in vivo experiment, targeted at devising therapeutics against the virus. Phylogenetic analysis further supports previous evidence that the SARS-CoV-2 is positioned with the SL-CoVZC45, BtRs-BetaCoV/YN2018B and the RS4231 Bat SARS-like corona viruses.

scholarly journals Filociclovir Is an Active Antiviral Agent against Ocular Adenovirus Isolates In Vitro and in the Ad5/NZW Rabbit Ocular Model

2021 ◽  
Vol 14 (4) ◽  
pp. 294
Author(s):  
Eric G. Romanowski ◽  
Islam T. M. Hussein ◽  
Steven C. Cardinale ◽  
Michelle M. Butler ◽  
Lucas R. Morin ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Topical Treatment ◽  
Antiviral Agent ◽  
Human Adenovirus ◽  
Treatment Groups ◽  
Ocular Infections ◽  
The Mean ◽  
Eye Infection

Presently, there is no FDA- or EMA-approved antiviral for the treatment of human adenovirus (HAdV) ocular infections. This study determined the antiviral activity of filociclovir (FCV) against ocular HAdV isolates in vitro and in the Ad5/NZW rabbit ocular model. The 50% effective concentrations (EC50) of FCV and cidofovir (CDV) were determined for several ocular HAdV types using standard plaque reduction assays. Rabbits were topically inoculated in both eyes with HAdV5. On day 1, the rabbits were divided into four topical treatment groups: (1) 0.5% FCV 4x/day × 10 d; (2) 0.1% FCV 4x/day × 10 d; (3) 0.5% CDV 2x/day × 7 d; (4) vehicle 4x/day × 10 d. Eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. The resulting viral eye titers were determined using standard plaque assays. The mean in vitro EC50 for FCV against tested HAdV types ranged from 0.50 to 4.68 µM, whereas those treated with CDV ranged from 0.49 to 30.3 µM. In vivo, compared to vehicle, 0.5% FCV, 0.1% FCV, and 0.5% CDV produced lower eye titers, fewer numbers of positive eye cultures, and shorter durations of eye infection. FCV demonstrated anti-adenovirus activity in vitro and in vivo.

scholarly journals Induction of cyclooxygenase-2 in rat vascular smooth muscle cells in vitro and in vivo.

1994 ◽  
Vol 269 (11) ◽  
pp. 8504-8509
Author(s):  
K.A. Pritchard ◽  
M.K. O'Banion ◽  
J.M. Miano ◽  
N. Vlasic ◽  
U.G. Bhatia ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Cyclooxygenase 2

Angiotensin II modulates frizzled-2 receptor expression in rat vascular smooth muscle cells

2005 ◽  
Vol 108 (6) ◽  
pp. 523-530 ◽  
Author(s):  
Giovanna CASTOLDI ◽  
Serena REDAELLI ◽  
Willy M. M. van de GREEF ◽  
Cira R. T. di GIOIA ◽  
Giuseppe BUSCA ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Aortic Smooth Muscle

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.

Surface culture of Steinernema sp. on two solid media and their pathogenicity against Galleria mellonella

2021 ◽  
Vol 95 ◽  
Author(s):  
C.I. Cortés-Martínez ◽  
A.I. Rodríguez-Hernández ◽  
M.R. López-Cuellar ◽  
N. Chavarría-Hernández
Keyword(s):  
Galleria Mellonella ◽  
Egg Yolk ◽  
Infective Juvenile ◽  
Surface Culture ◽  
Solid Media ◽  
Significant Difference ◽  
Bacterial Lawn ◽  
The Mean

Abstract The use of native entomopathogenic nematodes as biocontrol agents is a strategy to decrease the environmental impact of insecticides and achieve sustainable agriculture crops. In this study, the effect of the surface culture of Steinernema sp. JAP1 over two solid media at 23–27°C on infective juvenile (IJ) production and pathogenicity against Galleria mellonella larvae were investigated. First, the bacterial lawn on the surface of the media with egg yolk (P2) or chicken liver (Cl) were incubated in darkness at 30°C for 48 and 72 h, and 100 surface-sterilized IJs were added. Four harvests were conducted within the next 35 days and the mean accumulated production was superior on Cl (210 × 103 IJs) than on P2 (135 × 103 IJs), but the productivity decreased up to 10% when the incubation time of the bacterial lawn was of 72 h. The mean pathogenicity of in vitro- and in vivo-produced IJs were of 47–64% and 31%, respectively. It is worth noting that none of the two solid media had a statistically significant difference in IJ pathogenicity. Considering that the maximum multiplication factor of IJs on solid media was 2108 and that the pathogenicity against G. mellonella was outstanding, Steinernema sp. has a good potential for in vitro mass production.

Abstract 354: Lower Circulating Levels of Tumor Necrosis Factor Related Apoptosis-inducing Ligand (TRAIL) are Associated with Increased Sub-clinical Coronary Atherosclerosis among Smokers

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Aman Gupta ◽  
Divay Chandra ◽  
Yingze Zhang ◽  
Steven Reis ◽  
Frank Sciurba
Keyword(s):  
Tumor Necrosis Factor ◽  
Coronary Atherosclerosis ◽  
Tumor Necrosis ◽  
Smoking Status ◽  
Calcium Score ◽  
Meso Scale Discovery ◽  
The Mean ◽  
Necrosis Factor

Rationale: There is significant in vitro evidence demonstrating anti-atherogenic effect of circulating Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). Also, decreased circulating TRAIL levels have been reported in patients with acute myocardial infarction and in those undergoing coronary catheterization due to suspected coronary atherosclerosis. However, it remains unknown if TRAIL levels are associated with sub-clinical coronary atherosclerosis. Methods: The study included 460 current and former smokers enrolled in the Pittsburgh COPD SCCOR study. Serum TRAIL levels were measured by electrochemiluminescence immunoassay, according to the manufacture’s protocol (Meso Scale Discovery, Gaithersburg, Maryland). Coronary atherosclerosis was assessed by a validated visual coronary artery calcium scoring system using non-EKG gated chest CT scans (Weston score). Ordinal logistic regression models were used to identify significant associations between categories of CAC score (0, 1-3, 4-8, and 9-12) and TRAIL level, and to adjust for cardiovascular risk factors. Results: The mean age of the 460 participants was 65.7 ± 6.3 years, 52.2% were male, and the mean pack years of smoking was 55.0 ± 30.8 years. In univariate analyses, each standard deviation decrease in TRAIL levels was associated with 1.42-fold increase in the odds of having calcium scores in one higher category (p<0.001). This association persisted despite adjustment for age, gender, race, body mass index, hypertension, diabetes, hyperlipidemia, pack years of smoking, and current smoking status (adjusted OR for higher category of calcium score per SD decrease in TRAIL level 1.22, p=0.04). Conclusions: Our results expand on the in vitro and in vivo data linking decreased TRAIL levels with increased atherosclerosis by demonstrating a novel association between lower circulating TRAIL and increased subclinical coronary atherosclerosis.

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