In vivo aortic wall characteristics at the early stage of atherosclerosis in rabbits

1997 ◽  
Vol 273 (3) ◽  
pp. H1142-H1147 ◽  
Author(s):  
K. Hironaka ◽  
M. Yano ◽  
M. Kohno ◽  
T. Tanigawa ◽  
M. Obayashi ◽  
...  
Keyword(s):  
Receptor Agonist ◽  
Aortic Wall ◽  
Early Stage ◽  
Aortic Pressure ◽  
Normal Diet ◽  
Acute Administration ◽  
Wide Range ◽  
Before And After ◽  
Vascular Responsiveness

To assess whether vascular responsiveness to alpha-receptor agonist is altered at the early stage of atherosclerosis, in vivo aortic pressure-diameter relationship of the aorta over a wide range of pressures was analyzed before and after the acute administration of alpha-receptor agonist (phenylephrine) in nine hypercholesterolemic fat-fed (7-wk-old) rabbits and eight normal diet-fed (7-wk-old) rabbits. In hypercholesterolemic fat-fed rabbits, there was no major structural change in the aortic wall except fatty streak, despite a marked increase in the level of plasma cholesterol, indicating the early stage of atherosclerosis of the aorta. By using a modified three-element Maxwell model, diastolic stress-strain relationship was computed after applying several assumptions to the actual aortic pressure-diameter relationship. After the intravenous administration of phenylephrine at a rate of 5 micrograms.kg-1.min-1, the stress (ordinate)-strain (abscissa) relationship curves were shifted to the left, indicating the activation of aortic smooth muscle by phenylephrine. The difference between the stress before and after phenylephrine showed a single peak at a certain strain. The peak difference in the stress was smaller in hypercholesterolemic fat-fed rabbits than in normal diet-fed rabbits, indicating the reduction of vascular responsiveness at the early stage of atherosclerosis of the aorta.

Increased alpha 1-adrenergic vascular sensitivity during development of hypertension in conscious dogs

1993 ◽  
Vol 264 (4) ◽  
pp. H1259-H1268 ◽  
Author(s):  
N. Uemura ◽  
D. E. Vatner ◽  
Y. T. Shen ◽  
J. Wang ◽  
S. F. Vatner
Keyword(s):  
Adrenergic Receptor ◽  
Peripheral Resistance ◽  
Aortic Pressure ◽  
Conscious Dogs ◽  
Aortic Tissue ◽  
Ang Ii ◽  
Receptor Density ◽  
Adrenergic Stimulation ◽  
Before And After ◽  
Vascular Responsiveness

The goal of this study was to determine whether enhanced vascular responsiveness during the development of perinephritic hypertension is selective or nonspecific. The effects of graded infusions of norepinephrine (NE), phenylephrine (PE), angiotensin II (ANG II), and vasopressin (VP) were examined on mean arterial pressure, total peripheral resistance (TPR), and aortic pressure-diameter relationships in conscious dogs. NE increased TPR significantly greater (P < 0.01) in hypertension than normotension, as did PE infusion, whereas ANG II and VP increased TPR similarly before and after hypertension. Analysis of aortic pressure-diameter relationships also demonstrated significant (P < 0.05) shifts in response to NE and PE, but not ANG II and VP, during the development of hypertension. In normotensive dogs, low doses of ANG II infusion also enhanced the vasoconstrictor response not only to NE and PE but also to VP. In contrast to what was observed in hypertension, in the presence of ANG II infusion after ganglionic blockade, enhanced responses to PE and NE were no longer observed. The alpha 1-adrenergic receptor density in membrane preparations from aortic tissue, as determined by [3H]prazosin binding, was higher (P < 0.05) in hypertensive dogs than control dogs. Thus the vascular responsiveness in the aorta and resistance vessels is enhanced to alpha 1-adrenergic stimulation, but not to all vasoconstrictors, during developing perinephritic hypertension. The mechanism appears to involve increased alpha 1-adrenergic receptor density.

Microtubule modulation of biliary excretion of endogenous and exogenous hepatic lysosomal constituents

1984 ◽  
Vol 246 (1) ◽  
pp. G8-G15 ◽  
Author(s):  
R. B. Sewell ◽  
S. S. Barham ◽  
A. R. Zinsmeister ◽  
N. F. LaRusso
Keyword(s):  
Lysosomal Enzyme ◽  
Biliary Excretion ◽  
Lysosomal Enzymes ◽  
Male Rats ◽  
Enzyme Secretion ◽  
Initial Increase ◽  
Acute Administration ◽  
Subsequent Decrease ◽  
Before And After

We tested the hypothesis that hepatocyte microtubules modulate the biliary excretion of endogenous and exogenous constituents of hepatocyte lysosomes. We collected bile via bile fistulas from male rats before and after acute administration of colchicine and vinblastine, agents known to bind to hepatocyte microtubules; rats were then killed and livers were homogenized for biochemical analyses or processed for electron microscopy. Colchicine caused biphasic, parallel alterations in the biliary excretion of three lysosomal enzymes compared with control rats given saline or lumicolchicine; a peak rise in enzyme outputs of approximately 175% at 45-60 min after colchicine administration was followed by a sustained fall to approximately 25% of control values, which persisted for 2-4 h. When hepatocyte lysosomes were prelabeled in vivo by administration of [3H]Triton WR-1339, a nonionic detergent that is sequestered in hepatic lysosomes, the biliary excretion of radiolabel in response to colchicine paralleled the biliary excretion of the three lysosomal enzymes. Vinblastine also induced a biphasic response in biliary lysosomal enzyme output that was similar to that produced by colchicine administration. Morphometric analysis of electron micrographs of rat livers demonstrated changes in the number of lysosomelike vesicles in the vicinity of bile canaliculi after colchicine and vinblastine administration; the initial increase in lysosomal enzyme secretion was associated with a significant decrease in the number of pericanalicular lysosomes after both agents, while the subsequent decrease in enzyme secretion coincided with an increase in the number of pericanalicular lysosomes after vinblastine.(ABSTRACT TRUNCATED AT 250 WORDS)

THE EFFECT OF A NEW ANTISEPTIC (l,6-DI-4′-CHLOROPHENYLDIGUANIDOHEXANE) ON SKIN FLORA

1956 ◽  
Vol 2 (2) ◽  
pp. 87-93 ◽  
Author(s):  
G. E. Myers ◽  
W. C. MacKenzie ◽  
K. A. Ward
Keyword(s):  
Aqueous Solution ◽  
Exposure Time ◽  
Bactericidal Activity ◽  
Wide Range ◽  
Skin Flora ◽  
Before And After ◽  
Measured Time ◽  
Skin Biopsies

A tincture and an aqueous solution containing 0.5% of 1,6-di-4′-chlorophenyl-diguanidohexane were tested in vivo as preoperative skin antiseptics. Skin biopsies were taken from various operative sites before and after a measured time of exposure to the antiseptic. Various periods of exposure were employed. The antiseptic was neutralized immediately at the end of the exposure time and bactericidal activity was tested by a standardized series of culture procedures. Tested under these conditions both the 0.5% aqueous solution and the 0.5% tincture possess marked skin disinfecting properties against a wide range of microorganisms.

scholarly journals T cell lineage choice and differentiation in the absence of the RNase III enzyme Dicer

2005 ◽  
Vol 201 (9) ◽  
pp. 1367-1373 ◽  
Author(s):  
Bradley S. Cobb ◽  
Tatyana B. Nesterova ◽  
Elizabeth Thompson ◽  
Arnulf Hertweck ◽  
Eric O'Connor ◽  
...  
Keyword(s):  
T Cell ◽  
Mammalian Cells ◽  
Early Stage ◽  
Early Embryo ◽  
Specific Gene ◽  
Small Interfering Rnas ◽  
Developmentally Regulated ◽  
Micro Rnas ◽  
Wide Range

The ribonuclease III enzyme Dicer is essential for the processing of micro-RNAs (miRNAs) and small interfering RNAs (siRNAs) from double-stranded RNA precursors. miRNAs and siRNAs regulate chromatin structure, gene transcription, mRNA stability, and translation in a wide range of organisms. To provide a model system to explore the role of Dicer-generated RNAs in the differentiation of mammalian cells in vivo, we have generated a conditional Dicer allele. Deletion of Dicer at an early stage of T cell development compromised the survival of αβ lineage cells, whereas the numbers of γδ-expressing thymocytes were not affected. In developing thymocytes, Dicer was not required for the maintenance of transcriptional silencing at pericentromeric satellite sequences (constitutive heterochromatin), the maintenance of DNA methylation and X chromosome inactivation in female cells (facultative heterochromatin), and the stable shutdown of a developmentally regulated gene (developmentally regulated gene silencing). Most remarkably, given that one third of mammalian mRNAs are putative miRNA targets, Dicer seems to be dispensable for CD4/8 lineage commitment, a process in which epigenetic regulation of lineage choice has been well documented. Thus, although Dicer seems to be critical for the development of the early embryo, it may have limited impact on the implementation of some lineage-specific gene expression programs.

Aminophylline and human diaphragm strength in vivo

1990 ◽  
Vol 68 (6) ◽  
pp. 2591-2596 ◽  
Author(s):  
R. D. Levy ◽  
S. Nava ◽  
L. Gibbons ◽  
F. Bellemare
Keyword(s):  
Motor Units ◽  
Normal Subjects ◽  
Acute Administration ◽  
Transdiaphragmatic Pressure ◽  
Gastric Pressure ◽  
Significant Difference ◽  
Before And After ◽  
Normal Human ◽  
Twitch Characteristics

The transdiaphragmatic pressure (Pdi) twitch response to single shocks from supramaximal bilateral phrenic nerve stimulation was studied before and after acute intravenous infusions of aminophylline [14.9 +/- 3.1 (SD) micrograms/ml] in nine normal subjects. Stimulation was performed with subjects in the sitting position against an occluded airway from end expiration. Baseline gastric pressure and abdominal and rib cage configuration were kept constant. There was no significant difference in peak twitch Pdi from the relaxed diaphragm between control (38.8 +/- 3.3 cmH2O) and aminophylline (40.2 +/- 5.2 cmH2O) experiments. Other twitch characteristics including contraction time, half-relaxation time, and maximum relaxation rate were also unchanged. The Pdi-twitch amplitude at different levels of voluntary Pdi was measured with the twitch occlusion technique, and this relationship was found to be similar under control conditions and after aminophylline. With this technique, maximum Pdi (Pdimax) was calculated as the Pdi at which stimulation would result in no Pdi twitch because all motor units are already maximally activated. No significant change was found in mean calculated Pdimax between control (146.9 +/- 27.0 cmH2O) and aminophylline (149.2 +/- 26.0 cmH2O) experiments. We conclude from this study that the acute administration of aminophylline at therapeutic concentrations does not significantly affect contractility or maximum strength of the normal human diaphragm in vivo.

Acute administration of GPR40 receptor agonist potentiates glucose-stimulated insulin secretion in vivo in the rat

Metabolism ◽  
2009 ◽  
Vol 58 (3) ◽  
pp. 333-343 ◽  
Author(s):  
Lalit S. Doshi ◽  
Manoja K. Brahma ◽  
Sufyan G. Sayyed ◽  
Amol V. Dixit ◽  
Prakash G. Chandak ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Receptor Agonist ◽  
Acute Administration ◽  
Insulin Secretion In Vivo ◽  
Glucose Stimulated Insulin Secretion

scholarly journals Heme Induction with Delta-Aminolevulinic Acid Stimulates an Increase in Water and Electrolyte Excretion

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Syed Quadri ◽  
Debra W. Jackson ◽  
Priyanka Prathipati ◽  
Courtney Dean ◽  
Keith E. Jackson
Keyword(s):  
Carbon Monoxide ◽  
Renal Function ◽  
Aminolevulinic Acid ◽  
Acute Administration ◽  
Bolus Administration ◽  
Sprague Dawley ◽  
Electrolyte Excretion ◽  
Sprague Dawley Rats ◽  
Before And After

Purpose. Studies were performed to examine hemodynamic and renal function before and after acute induction of the endogenous CO system with delta-aminolevulinic acid (DALA), which drives HO activity.Methods.In vivostudies were conducted on Inactin-anesthetized male Sprague Dawley rats (250–300 g) either with or without chronic pretreatment with L-NAME (50 mg/Kg, q12 hours x4d).Results. DALA (80 μmol/Kg, IV bolus) administration acutely increased endogenous CO production and HO-1 protein. In untreated and L-NAME-pretreated rats, DALA did not alter BP, GFR, or RBF but increased UF,UNaV, andUKV(untreated: Δ108.8 ± 0.28%, 172.1 ± 18.4%, and 165.2 ± 45.9%; pretreated: Δ109.4 ± 0.29%, 187.3 ± 26.9%, and 197.2 ± 45.7%). Acute administration of biliverdin (20 mg/kg, IV) and bilirubin (30 mg/kg, IV) to similarly treated animals did not alter UF,UNaV, andUKV.Conclusion. These results demonstrate that heme oxygenase induction increases urine and electrolyte excretion and suggest a direct tubular action of endogenous carbon monoxide.

scholarly journals PSEUDOEXPHOLIATIVE SYNDROME

2019 ◽  
Vol 23 (1) ◽  
pp. 54-61
Author(s):  
B. B. Bekmirova ◽  
M. A. Frolov
Keyword(s):  
Early Stage ◽  
Low Vision ◽  
Cataract Extraction ◽  
Surgical Approaches ◽  
Surgical Interventions ◽  
Wide Range ◽  
Common Causes ◽  
Before And After ◽  
Initial Appearance ◽  
Modern Level

Today, the clouding of the lens is one of the common pathology of the organ of vision. The clouding of the lens-cataract is one of the most common causes of blindness and low vision in children and adults. According to most authors, the main method of cataract treatment is surgical. In modern cataract surgery, the leading place is occupied by the most common cataract extraction method, phacoemulsification. The modern level of phacoemulsification technology made it possible to perform operations less traumatic, gave a full restoration of visual functions. It makes no sense to talk about the indications of IOL implantation, since Currently, there is a wide range of IOL models that can be implanted for all types of complicated cataracts. It is advisable to talk about contraindications, in this case, the surgeon makes a decision based on the material capabilities, experience, and perfection of the surgical technique. There are various associated syndromes in the development of cataracts. One of the syndromes that occurs in cataracts is the pseudo-excoliation syndrome. This review addresses the unresolved issues of pseudoexfoliation syndrome. The results of studies of some scientists, data analysis, clinical cases and ways to solve this problem are considered. In particular, a number of questions remain about the tactics of patient administration before and after surgical interventions. This syndrome, as far as we know, affects the development and outcome of the disease. It is sometimes difficult to diagnose pseudo-excoliation syndrome at an early stage, sometimes contradictory statements about the initial appearance of the syndrome are encountered. The issues of prevention of postoperative complications, less traumatic surgical approaches at various stages of PES remain open.

Effects of Clonidine on Aortic Pressure-Diameter and Elastic Stiffness-Stress Relations in Anaesthetized Rabbits

1981 ◽  
Vol 61 (3) ◽  
pp. 273-279 ◽  
Author(s):  
A. Friggi ◽  
H. Bodard
Keyword(s):  
Blood Pressure ◽  
Elastic Modulus ◽  
Aortic Wall ◽  
Muscle Tension ◽  
Blood Pressure Level ◽  
Aortic Pressure ◽  
Elastic Stiffness ◽  
Aortic Blood ◽  
Before And After ◽  
Aortic Blood Pressure

1. The effects of clonidine on the aortic pressure-diameter relationship were studied in anaesthetized rabbits by means of an ultrasonic dimension technique. Midwall aortic stress and aortic elastic modulus were calculated. 2. In spite of a significant decrease in mean aortic blood pressure, aortic diameter was slightly but not significantly increased after intravenous clonidine injection (25 μg/kg body wt., intravenously over 30 s). 3. Midwall aortic stress was decreased when compared at the same aortic radius and aortic elastic modulus was increased when compared at a common blood pressure level. However, when aortic elastic modulus was plotted as a linear function of the stress, no difference was observed before and after clonidine. 4. The results suggest that the pressure-diameter changes induced by clonidine were primarily reflecting the mechanical changes in the aortic wall due to changes in smooth muscle tension. Furthermore it seems that the elastic modulus of the aorta tends to remain constant by adaptive changes in the aortic wall which over-ride the concurrent geometrical changes to maintain a level of elasticity consistent with the degree of aortic stress.

Passage of labeled albumin into canine aortic wall in vivo and in vitro

1961 ◽  
Vol 200 (3) ◽  
pp. 622-624 ◽  
Author(s):  
Leroy E. Duncan ◽  
Katherin Buck
Keyword(s):  
Abdominal Aorta ◽  
Aortic Wall ◽  
Aortic Pressure ◽  
Ascending Aorta ◽  
Descending Aorta ◽  
Arterial Blood ◽  
Isolated Aorta ◽  
Abdominal Portion

The passage of labeled albumin into canine aortic wall in vivo and in vitro was studied. In vivo albumin entered the inner layer fastest in the ascending aorta and progressively less rapidly down the length of the aorta. In vitro, this gradient was partially preserved since albumin entered the inner layer of ascending aorta faster than that of descending aorta. The gradient was not completely preserved in vitro, since albumin entered the inner layer of abdominal aorta faster than that of descending thoracic aorta. The rapid entrance of albumin into the abdominal portion of the aorta in vitro appears to have been due to the maintenance of arterial blood pressure in the unusually dense capillary network of the abdominal aorta. The partial preservation of the gradient in the isolated aorta excludes phasic variation of intra- or extra-aortic pressure as a cause of the gradient.

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