scholarly journals Cat Heart Muscle in Vitro

1962 ◽  
Vol 46 (2) ◽  
pp. 201-213 ◽  
Author(s):  
Ernest Page
Keyword(s):  
Molecular Size ◽  
Water Soluble ◽  
Osmotic Gradient ◽  
Papillary Muscles ◽  
Total Water ◽  
Inulin Space ◽  
Soluble Molecule ◽  
Cat Heart ◽  
Molecular Radius

The "osmotic gradient" method, an intracellular microelectrode technique for determining whether an uncharged, water-soluble molecule enters cells or remains extracellular, is described. Using this method, a series of carbohydrates of graded molecular size were examined. In cat papillary muscles mannitol, molecular radius 4.0 Å, remained extracellular while arabinose, molecular radius 3.5 Å entered the cells. Measurement of the simultaneous uptake of H3-mannitol and C14-inulin showed that mannitol equilibrates with 40 per cent of total water in 1 hour, after which the mannitol space does not further increase. By contrast, inulin, molecular radius ∼15 Å, equilibrates with 24 per cent of total water in 1 hour; thereafter the inulin space continues to increase very slowly. The intracellular K concentrations are significantly higher and the intracellular Na and Cl concentrations significantly lower when mannitol rather than inulin is used to measure the extracellular space. The intracellular Cl concentration determined with Cl36 or Br82 is significantly higher than that calculated from the membrane potential assuming a passive Cl distribution. In addition, it is shown that choline enters and is probably metabolized by the cells of papillary muscle.

scholarly journals Cat Heart Muscle in Vitro

1960 ◽  
Vol 44 (2) ◽  
pp. 327-344 ◽  
Author(s):  
Ernest Page ◽  
A. K. Solomon
Keyword(s):  
Papillary Muscles ◽  
Total Water ◽  
Inulin Space ◽  
Wet Weight ◽  
K Concentration ◽  
Cell Volumes ◽  
Cat Heart ◽  
External K

Methods have been developed for the simultaneous determination of total water, inulin space, and K and Na content in muscles of 0.5 to 10 mg. wet weight. These methods have been used to define steady state conditions with respect to intracellular K concentration in papillary muscles from cat hearts perfused and contracting isometrically at 27–28°C. and at 37–38°C. Cell volumes and intracellular ionic concentrations have been followed as a function of the external K concentration and compared with values predicted on the basis of electroneutrality and osmotic equilibrium.

scholarly journals Cat Heart Muscle in Vitro

1966 ◽  
Vol 49 (4) ◽  
pp. 641-653 ◽  
Author(s):  
Ernest Page ◽  
S. R. Storm
Keyword(s):  
Cell Membrane ◽  
Heart Muscle ◽  
Dry Weight ◽  
Osmotic Gradient ◽  
Papillary Muscles ◽  
Sucrose Content ◽  
Cell Water ◽  
Muscle Water ◽  
Cat Heart

Cell contents of water, K, Na, and Cl have been determined in cat right ventricular papillary muscles immersed in solutions with and without NaCl when the external osmolality was varied with sucrose. The plot of cell water/kilogram dry weight (corrected for sucrose content) vs. (external osmolality)-1 suggests that not less than 82% of water present in cells at physiological external osmolality is free to move across the cell membrane in response to an imposed osmotic gradient. Cells fail to increase their water content in very hypotonic solutions. For osmolalities greater than 5 times isosmolal, at which the mannitol space and the Cl36 space are both equal to 100% of muscle water, rather large amounts of univalent cation appear to remain "bound" to the tissue.

Influence of pilocarpine on transport by salivary gland slices

1963 ◽  
Vol 205 (5) ◽  
pp. 1058-1062 ◽  
Author(s):  
L. H. Schneyer ◽  
C. A. Schneyer
Keyword(s):  
Salivary Gland ◽  
Submaxillary Gland ◽  
Nitrogen Atmosphere ◽  
Total Water ◽  
Early Effect ◽  
Apparent Loss ◽  
Inulin Space ◽  
Total Tissue

Effects of pilocarpine on net movements of water and electrolytes in gland cells were investigated in vitro, using slices from submaxillary gland of rat. Slices were depleted of K, and loaded with Na, Cl, and water, by incubation in Krebs-Ringer phosphate with nitrogen atmosphere. After this, the slices were transferred to Krebs-Ringer phosphate with oxygen atmosphere. During this period with O2, pilocarpine caused apparent loss of water from cells, since tissue total water decreased and inulin space remained almost unchanged. Without pilocarpine during this time, water in cells increased. Electrolyte movements were also affected by pilocarpine. Specifically, there occurred reduction in net accumulation of K in total tissue and cells. Reduction in net extrusion of Na was suggested. Since, in vivo, an early effect of stimulation involves depletion of gland K, it appears that the current observations have relevance to normal secretion to the extent, at least, that in both circumstances stimulating agents reduce the ability of the cells to maintain stores of K.

scholarly journals Cat Heart Muscle in Vitro

1962 ◽  
Vol 46 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Ernest Page
Keyword(s):  
Steady State ◽  
Heart Muscle ◽  
Potential Difference ◽  
Resting Potential ◽  
Equilibrium Potential ◽  
Papillary Muscles ◽  
K Concentration ◽  
Cat Heart ◽  
External K

The steady state transmembrane resting potential difference (Vm) has been measured in quiescent papillary muscles. Vm was determined as a function of the external K concentration in Cl and SO4 solutions and compared with the K equilibrium potential. Other measurements were made after replacement of external Na by choline, K by Rb and Cs, and Cl by SO4, CH3SO4, and NO3. Effects on Vm of albumin, temperature, and variation in internal K concentration are described.

Rationally developed core–shell polymeric-lipid hybrid nanoparticles as a delivery vehicle for cromolyn sodium: implications of lipid envelop on in vitro and in vivo behaviour of nanoparticles upon oral administration

RSC Advances ◽  
2015 ◽  
Vol 5 (93) ◽  
pp. 76491-76506 ◽  
Author(s):  
Ravi R. Patel ◽  
Gayasuddin Khan ◽  
Sundeep Chaurasia ◽  
Nagendra Kumar ◽  
Brahmeshwar Mishra
Keyword(s):  
Oral Administration ◽  
Oral Bioavailability ◽  
Water Soluble ◽  
Cromolyn Sodium ◽  
Hybrid Nanoparticles ◽  
Core Shell ◽  
Delivery Vehicle ◽  
Soluble Molecule

In the present study, cromolyn sodium, a highly water soluble molecule was encapsulated into rationally designed, core–shell polymeric-lipid hybrid nanoparticles for enhancing its oral bioavailability, by improving its intestinal permeability.

scholarly journals Cat Heart Muscle in Vitro

1965 ◽  
Vol 48 (5) ◽  
pp. 949-956 ◽  
Author(s):  
Ernest Page
Keyword(s):  
Steady State ◽  
Heart Muscle ◽  
Arrhenius Plot ◽  
Papillary Muscles ◽  
Wide Range ◽  
Heart Muscle Cells ◽  
Mammalian Heart Muscle ◽  
Apparent Activation Energies ◽  
Cat Heart

In quiescent cat papillary muscles JK, the rate of exchange of cellular K with K42 in the steady state, has been measured in the presence and absence of NaCl over a wide range of temperatures. JK was found to be independent of the presence of external NaCl under the steady state conditions investigated. The Arrhenius plot for K exchange was linear over a range of temperatures from 2.5 to 37.5°C in the absence of NaCl, and from 17.5 to 37.5°C in the presence of NaCl. The corresponding apparent activation energies were, respectively, 10,200 and 8,800 calories/mole. JK in the absence of NaCl was not affected by 10-5 M ouabain. These results are consistent with a passive distribution for the K of heart muscle cells. The observations suggest that a carrier-mediated forced exchange of K for Na does not occur during the steady state in mammalian heart muscle.

scholarly journals Enzymatic tracers in the study of vascular permeability.

1979 ◽  
Vol 27 (8) ◽  
pp. 1120-1130 ◽  
Author(s):  
N Simionescu
Keyword(s):  
Vascular Permeability ◽  
Molecular Size ◽  
Molecular Shape ◽  
Enzyme Concentration ◽  
Gel Chromatography ◽  
Microvascular Endothelium ◽  
Tracer Solution ◽  
Molecular Radius

Elucidation of the ultrastructural basis of vascular permeability was aided by the development of cytochemical techniques for visualizing the distribution, within the vessel wall, of intravenously injected peroxidatic enzymes of varying molecular size. Tracer enzymes available range from 10 A (hemeoctapeptide) to 52 A (catalase) effective molecular radius. The use of enzymatic probe molecules assumes a thorough characterization of: (a) the molecular charge (isoelectric point of the native enzyme, and when feasible, its polyanionic and polycationic derivatives; (b) effective molecular radius (ae); (c) peroxidase activity (to detect by spectrophotometry of DAB-oxidizing activity, the optimal pH, temperature, and enzyme concentration to be employed in the cytochemical procedure). Molecular shape and state of dispersion of the enzymatic probes should be determined by gel chromatography and spectrophotometry of both the tracer solution and aliquots of blood plasma collected after i.v. injection of the tracer. Conditions required for the probe administration include: (a) the investigation of potential side effects (tests for toxicity and vascular leakage) and (b) estimation of the tracer volume and concentration which does not affect significantly the blood volume and osmotic pressure. Determination in vitro of the crosslinking of tracer molecules induced by the aldehyde fixative to be employed, also gives an indication on potential diffusion artifacts. Based on the information thus obtained, the design of the cytochemical procedure should also take into account the possible use of methods for enhancing the peroxidatic reaction product: nitrogenous ligands (imidazole, diaminopyrimidine, histidine) or polyphenolic mordants (galloylglucoses). The usefulness of peroxidatic tracers in the investigation of vascular permeability is exemplified by some results obtained on the microvascular endothelium in vivo (trasncytosis, intercellular pathway, etc.), and on endothelial cells isolated from heart microvasculature.

scholarly journals Coenzyme Q10-Polyethylene Glycol Monostearate Nanoparticles: An Injectable Water-Soluble Formulation

Antioxidants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 86 ◽  
Author(s):  
Kengo Banshoya ◽  
Tetsuya Nakamura ◽  
Tetsuro Tanaka ◽  
Yoshiharu Kaneo
Keyword(s):  
Polyethylene Glycol ◽  
Coenzyme Q10 ◽  
Blood Circulation ◽  
Oxidant Stress ◽  
Aqueous Media ◽  
Molecular Size ◽  
Water Soluble ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

Therapeutic applications of coenzyme Q10 (CoQ10) are greatly limited by its lack of solubility in aqueous media. In this study, polyethylene glycol monostearate (stPEG) was used to construct micelles containing CoQ10 as a new formulation. The micellar formulations (stPEG/CoQ10) were prepared using five types of stPEG with 10, 25, 40, 55, and 140 PEG repeat units, respectively. The micellar preparation was simple, consisting of only stPEG and CoQ10. Next, we compared the physical properties and blood circulation of these micelles. The CoQ10 load of this formulation was approximately 15 w/w%. Based on the dynamic light scattering method, the average molecular size of the stPEG/CoQ10 micelles was approximately 15 to 60 nm. The zeta potentials of these micelles were approximately −10 to −25 mV. The micelles using stPEG25, 40, and 55 demonstrated high solubility in water. Furthermore, these micelles had in vitro antioxidant activity. On comparing the blood circulation of micelles using stPEG25, 40, 55, and 140, micelles using stPEG55 had a significantly higher circulation in blood. The stPEG55/CoQ10 micelle demonstrated a protective effect against acetaminophen-induced liver injury in mice. In conclusion, these data indicate that the intravenous administration of the stPEG/CoQ10 micellar aqueous formulation is of great value against oxidant stress.

Controlled Release of Metformin Hydrochloride I. In vitro Release from Physical Mixture Containing Xanthan Gum as Hydrophilic Rate Retarding Polymer

1970 ◽  
Vol 4 (1) ◽  
Author(s):  
Mashkura Ashrafi ◽  
Jakir Ahmed Chowdhury ◽  
Md Selim Reza
Keyword(s):  
Controlled Release ◽  
Xanthan Gum ◽  
In Vitro Release ◽  
Correlation Coefficients ◽  
High Ratio ◽  
Water Soluble ◽  
Metformin Hydrochloride ◽  
Model Drug ◽  
Very High

Capsules of different formulations were prepared by using a hydrophilic polymer, xanthan gum and a filler Ludipress. Metformin hydrochloride, which is an anti-diabetic agent, was used as a model drug here with the aim to formulate sustained release capsules. In the first 6 formulations, metformin hydrochloride and xanthan gum were used in different ratio. Later, Ludipress was added to the formulations in a percentage of 8% to 41%. The total procedure was carried out by physical mixing of the ingredients and filling in capsule shells of size ‘1’. As metformin hydrochloride is a highly water soluble drug, the dissolution test was done in 250 ml distilled water in a thermal shaker (Memmert) with a shaking speed of 50 rpm at 370C &plusmn 0.50C for 6 hours. After the dissolution, the data were treated with different kinetic models. The results found from the graphs and data show that the formulations follow the Higuchian release pattern as they showed correlation coefficients greater than 0.99 and the sustaining effect of the formulations was very high when the xanthan gum was used in a very high ratio with the drug. It was also investigated that the Ludipress extended the sustaining effect of the formulation to some extent. But after a certain period, Ludipress did not show any significant effect as the pores made by the xanthan gum network were already blocked. It is found here that when the metformin hydrochloride and the xanthan gum ratio was 1:1, showed a high percentage of drug release, i.e. 91.80% of drug was released after 6 hours. But With a xanthan gum and metformin hydrochloride ratio of 6:1, a very slow release of the drug was obtained. Only 66.68% of the drug was released after 6 hours. The percent loading in this case was 14%. Again, when Ludipress was used in high ratio, it was found to retard the release rate more prominently. Key words: Metformin Hydrochloride, Xanthan Gum, Controlled release capsule Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

NGHIÊN CỨU ẢNH HƯỞNG CỦA CHITOSAN HOÀ TAN TRONG NƯỚC ĐẾN NẤM Colletotrichum musae D1 GÂY BỆNH THÁN THƯ TRÊN CHUỐI Ở ĐIỀU KIỆN IN VITRO

2016 ◽  
Vol 119 (5) ◽  
Author(s):  
Lê Thanh Long ◽  
Nguyễn Văn Toản ◽  
Nguyễn Văn Huế ◽  
Trang Sĩ Trung ◽  
Vũ Ngọc Bội
Keyword(s):  
Water Soluble ◽  
28S Rrna ◽  
Colletotrichum Musae

Chủng D1 phân lập từ các mẫu chuối có vết bệnh thán thư điển hình được sử dụng để nghiên cứu khả năng kháng nấm của chitosan hoà tan trong nước (Water-soluble chitosan_WSC) ở điều kiện in vitro. Kết quả phân tích trình tự gen mã hoá 28S rRNA của chủng D1 cho thấy tương đồng trình tự cao với các trình tự tương ứng của loài Colletotrichum musae và được ký hiệu là Colletotrichum musae D1. Kết quả các thí nghiệm đều cho thấy C. musae D1 rất nhạy cảm với WSC, hiệu lực ức chế tăng khi tăng nồng độ WSC xử lý ở điều kiện in vitro. Trên môi trường PDA, nồng độ 1,6% WSC ức chế hoàn toàn sự sinh trưởng của sợi nấm C. musae D1, nồng độ ức chế 50% (PIRG50) và nồng độ ức chế tối thiểu 90% (MIC90) tương ứng với nồng độ WSC 0,28% và 0,88%. Trong môi trường PDB, giá trị IC50 và MIC90 tương ứng là 0,11% và 0,43% và sự phát triển của sợi nấm C. musae D1 bị ức chế hoàn toàn ở nồng độ 0,8%. WSC không chỉ ức chế sự nảy mầm mà còn gây biến đổi bất thường bào tử nấm khi quan sát trên kính hiển vi.

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