scholarly journals Efficacy of systemic administration of riboflavin on a rabbit model of corneal alkali burn

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maksym Żuk ◽  
Ekaterina Lobashova ◽  
Olga Żuk ◽  
Sławomir Wierzba
Keyword(s):  
Ciliary Body ◽  
Aqueous Humour ◽  
Femoral Vein ◽  
Scintillation Counter ◽  
Rabbit Model ◽  
Total Radioactivity ◽  
Traumatic Injuries ◽  
Administration And Dosage ◽  
Short Period ◽  
Femoral Muscle

Abstract Changes in the barrier mechanisms in the eye should determine the rational route for the administration and dosage of each drug in the treatment of traumatic injuries and other pathologies. The aim of this study was to examine the efficacy of intra-arterial delivery of 14C-riboflavin (as an “indicator”) and compare it with intravenous and intramuscular administration in an animal model of chemical eye burn. 14C-riboflavin (14C-I) was administered by intra-arterial (carotid artery), intravenous (femoral vein) and intramuscular (femoral muscle) routes. The total radioactivity was determined over 2 h in the plasma and structures of the rabbit’s eyes using a scintillation counter. The results of the study show that intravascular administration of 14C-I gives significantly higher concentrations of total radioactivity in the blood and is accompanied by a significant increase in the permeability of the blood-barrier and barrier in eyes suffering from burns. The highest concentration in the plasma and aqueous humour of the anterior chamber of the eye was observed during the first hour with the intra-arterial route of administration of 14C-I in either burnt and unburnt eyes. The distribution of total radioactivity in the structures of the eye over the 2 h of the experiment showed a higher level of the drug under intra-arterial administered in the uveal regions, namely: the iris, ciliary body, choroid, retina and also the sclera and cornea. This experimental model shows that intra-arterial administration can increase the bioavailability of a drug to the structures of the eye within a short period of time.

scholarly journals A weakly acidic solution containing deoxycholic acid induces esophageal epithelial apoptosis and impairs integrity in an in vivo perfusion rabbit model

2016 ◽  
Vol 310 (7) ◽  
pp. G487-G496 ◽  
Author(s):  
Nicolas A. Pardon ◽  
Maria Vicario ◽  
Hanne Vanheel ◽  
Tim Vanuytsel ◽  
Laurens J. Ceulemans ◽  
...  
Keyword(s):  
Deoxycholic Acid ◽  
Acidic Solution ◽  
Rabbit Model ◽  
Esophageal Epithelium ◽  
Epithelial Integrity ◽  
Mucosal Integrity ◽  
Short Period ◽  
Weakly Acidic Solution

Impaired esophageal mucosal integrity may be an important contributor in the pathophysiology of gastroesophageal reflux disease (GERD). Nevertheless, the effect of potentially harmful agents on epithelial integrity is mainly evaluated in vitro for a short period of time and the possible induction of epithelial apoptosis has been neglected. Our objective was to assess the effect of an acidic and weakly acidic solution containing deoxycholic acid (DCA) on the esophageal epithelium in an in vivo rabbit model of esophageal perfusion and to evaluate the role of the epithelial apoptosis. The esophagus of 55 anesthetized rabbits was perfused for 30 min with different solutions at pH 7.2, pH 5.0, pH 1.0, and pH 5.0 containing 200 and 500 μM DCA. Thereafter, animals were euthanized immediately or at 24 or 48 h after the perfusion. Transepithelial electrical resistance, epithelial dilated intercellular spaces, and apoptosis were assessed in Ussing chambers, by transmission electron microscopy, and by TUNEL staining, respectively. No macroscopic or major microscopic alterations were observed after the esophageal perfusions. The acidic and weakly acidic solution containing DCA induced similar long-lasting functional impairment of the epithelial integrity but different ultrastructural morphological changes. Only the solution containing DCA induced epithelial apoptosis in vivo and in vitro in rabbit and human tissue. In contrast to acid, a weakly acidic solution containing DCA induces epithelial apoptosis and a long-lasting impaired mucosal integrity. The presence of apoptotic cells in the esophageal epithelium may be used as a marker of impaired integrity and/or bile reflux exposure.

Nepafenac in the Prevention and Treatment of Ocular Inflammation and Pain Following Cataract Surgery and in the Prevention of Post-operative Macular Oedema in Diabetic Patients

2012 ◽  
Vol 06 (03) ◽  
pp. 169 ◽  
Author(s):  
Marco Nardi ◽  
Keyword(s):  
Cataract Surgery ◽  
Targeted Delivery ◽  
Macular Oedema ◽  
Ciliary Body ◽  
Rabbit Model ◽  
Prostaglandin E ◽  
Diabetic Patients ◽  
Corneal Permeability ◽  
Study Results ◽  
Prevention And Treatment

Nepafenac ophthalmic suspension is a topical non-steroidal anti-inflammatory drug (NSAID) approved in the US and Europe for prevention and treatment of post-operative pain and inflammation associated with cataract surgery, and recently approved in Europe for reduction in risk of post-operative macular oedema associated with cataract surgery in diabetic patients. Unlike conventional NSAIDs, nepafenac is a prodrug that is uncharged and this results in great corneal permeability. Experimental studies on nepafenac demonstrated enhanced permeability compared with other NSAIDs, and rapid bioactivation to amfenac by intraocular hydrolases within ocular tissues including ciliary body epithelium, retina, choroid and cornea, which results in targeted delivery of active drug to anterior and posterior segments. Furthermore, these study results have been confirmed in clinical trials. Nepafenac may have prolonged activity in vascularised tissues of the eye because bioconversion is targeted to the iris/ciliary body, and to a greater extent the retina and choroid. Nepafenac and amfenac are potent inhibitors of cyclo-oxygenase (COX) enzyme isoforms, COX-1 and COX-2. Topical nepafenac penetrated into the posterior segment in a rabbit model of concanavalin-A induced retinal inflammation, where it diminished vitreous protein and prostaglandin E2concentrations and reduced breakdown of the blood–retinal barrier. Other NSAIDs, including ketorolac, failed to reduce the increase of these inflammatory markers in the same study. A randomised clinical study showed that based on retinal thickening and vision, treatment with nepafenac beginning pre-surgery and used for up to 90 days post-cataract surgery is effective in preventing macular oedema and associated loss of visual acuity in diabetic patients.

The Measurement of Intestinal Calcium Absorption by External Radioisotope Counting: Application to Study of Nephrolithiasis

1970 ◽  
Vol 39 (1) ◽  
pp. 95-106 ◽  
Author(s):  
M. R. Wills ◽  
E. Zisman ◽  
J. Wortsman ◽  
R. G. Evens ◽  
C. Y. C. Pak ◽  
...  
Keyword(s):  
Calcium Absorption ◽  
Scintillation Counter ◽  
Renal Stones ◽  
Normal Subjects ◽  
Total Radioactivity ◽  
Urinary Calcium ◽  
Intestinal Calcium Absorption ◽  
Absolute Amount ◽  
Calcium Load ◽  
Fractional Calcium Absorption

1. Gastro-intestinal absorption of calcium was studied in man by the measurement of forearm radioactivity in a large-volume liquid scintillation counter following separate oral and intravenous doses of 47CaCl2. From the ratio of the percentages of total radioactivity appearing in the forearm following these separate determinations the fractional absorption of calcium was estimated. 2. Changes of forearm radioactivity with time following the administration of this isotope were studied; evidence is presented that the radioactivity in the forearm at 4 h after administration of the isotope gives a valid assessment of fractional calcium absorption. 3. Fractional calcium absorption determined by this technique correlated well with the net calcium absorption as determined from stool radioactivity after oral administration of isotope. 4. In normal subjects it was shown that fractional calcium absorption measured by this technique varies inversely with the stable calcium load and that the absolute amount of calcium absorbed from given loads increases with the size of the load in the range 20–1000 mg calcium. 5. Gastro-intestinal calcium absorption was measured at various oral calcium loads in a group of fifteen patients with recurrent calcium-containing renal stones. All the patients were normocalcaemic; some had hypercalciuria. In the patients with hypercalciuria, calcium absorption, fractional and absolute, was significantly increased at all calcium loads as compared to that of patients with normal urinary calcium. 6. It is concluded that hyperabsorption of calcium from the gastro-intestinal tract plays a crucial role in the aetiology of hypercalciuria, probably by causing an increase in the renal filtered calcium load.

Extraocular Application of Mitomycin C in a Rabbit Model: Cytotoxic Effects on the Ciliary Body and Epithelium

1994 ◽  
Vol 25 (4) ◽  
pp. 240-244 ◽  
Author(s):  
Holger Mietz ◽  
Klaus Addicks ◽  
Michael Diestelhorst ◽  
Günter K Krieglstein
Keyword(s):  
Mitomycin C ◽  
Ciliary Body ◽  
Rabbit Model ◽  
Cytotoxic Effects

scholarly journals Peripheral vascular complications following totally endoscopic cardiac surgery

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ling-chen Huang ◽  
Qi-chen Xu ◽  
Dao-zhong Chen ◽  
Xiao-fu Dai ◽  
Liang-wan Chen
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Minimally Invasive ◽  
Femoral Artery ◽  
Femoral Vein ◽  
Vascular Complications ◽  
Minimally Invasive Cardiac Surgery ◽  
Venous Cannulation ◽  
Artery Cannulation ◽  
Short Period

Abstract Background Clinical application of minimally invasive cardiac surgery has increased annually. Cardiopulmonary bypass is established by peripheral cannulation during minimally invasive cardiac surgery. The methodology of peripheral cannulation has unique characteristics, which have associated risks and complications. Few studies have been conducted on this topic. In this study, we focused on complications of peripheral cannulation in totally endoscopic cardiac surgery. Methods Patients who underwent totally endoscopic cardiac surgery with cardiopulmonary bypass established by peripheral cannulation at our institution between January 2019 and June 2020 were reviewed. Specific cannulation strategies and related cannulation complications were noted. Results One hundred forty-eight patients underwent totally endoscopic cardiac surgery. One hundred forty-eight cannulations were performed in the femoral artery and vein, and eleven were performed in the internal jugular vein (combined with the femoral vein). The median size of the femoral artery cannula was 22Fr, and that of the venous canula was 24Fr. One patient died of retroperitoneal haematoma due to femoral artery injury. Three patients had postoperative lower limb oedema. One patient had a postoperative diagnosis of femoral vein thrombosis. Conclusions Different from cannulation in patients with aortic dissection and aneurysms, femoral artery cannulation is safe in totally endoscopic cardiac surgery. Venous cannulation is characterized by a large-bore venous cannula and a short period of use. There are few reports about complications of venous cannulation. The main complication in this study was mechanical injury, and the key to preventing this injury is meticulous manipulation during surgery.

Bile acid flux through portal but not peripheral veins inhibits CYP7A1 expression without involvement of ileal FGF19 in rabbits

2014 ◽  
Vol 307 (4) ◽  
pp. G479-G486 ◽  
Author(s):  
Quan Shang ◽  
Grace L. Guo ◽  
Akira Honda ◽  
Daniel Shi ◽  
Monica Saumoy ◽  
...  
Keyword(s):  
Bile Acid ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Femoral Vein ◽  
Splenic Vein ◽  
Rabbit Model ◽  
Farnesoid X Receptor ◽  
Fibroblast Growth ◽  
Protein Levels ◽  
Fgf19 Expression

It was proposed that CYP7A1 expression is suppressed through the gut-hepatic signaling pathway fibroblast growth factor (FGF) 15/19-fibroblast growth factor receptor 4, which is initiated by activation of farnesoid X receptor in the intestine rather than in the liver. The present study tested whether portal bile acid flux alone without ileal FGF19 could downregulate CYP7A1 expression in rabbits. A rabbit model was developed by infusing glycodeoxycholic acid (GDCA) through the splenic vein to bypass ileal FGF19. Study was conducted in four groups of rabbits: control; bile fistula + bovine serum albumin solution perfusion (BF); BF + GDCA (by portal perfusion); and BF + GDCA-f (by femoral perfusion). Compared with only BF, BF + GDCA (6 h portal perfusion) suppressed CYP7A1 mRNA, whereas BF + GDCA-f (via femoral vein) with the same perfusion rate of GDCA did not show inhibitory effects. Meanwhile, there was a decrease in ileal FGF19 expression and portal FGF19 protein levels, but an equivalent increase in biliary bile acid outputs in both GDCA perfusion groups. This study demonstrated that portal bile acid flux alone downregulated CYP7A1 expression with diminished FGF19 expression and protein levels, whereas the same bile acid flux reaching the liver through the hepatic artery via femoral vein had no inhibitory effect on CYP7A1. We propose that bile acid flux through the portal venous system may be a kind of “intestinal factor” that suppresses CYP7A1 expression.

scholarly journals Metabolism of Ciliary Body in Relation to Formation of Aqueous Humour

Nature ◽  
1964 ◽  
Vol 201 (4919) ◽  
pp. 621-621 ◽  
Author(s):  
M. V. RILEY ◽  
V. BARONCELLI
Keyword(s):  
Ciliary Body ◽  
Aqueous Humour

scholarly journals Sequential determination of 99Tc and 126Sn in radioactive concentrate

2017 ◽  
Vol 10 (1) ◽  
pp. 61-64 ◽  
Author(s):  
Veronika Silliková ◽  
Silvia Dulanská
Keyword(s):  
Anion Exchange ◽  
Exchange Resin ◽  
Scintillation Counter ◽  
Cation Exchange Resin ◽  
Sequential Method ◽  
Time Activity ◽  
Sequential Determination ◽  
Short Period ◽  
Time Required

Abstract This paper describes a new sequential method using anion exchange resin, which is commercially available from Eichrom Technologies, Inc., for the determination of 99Tc and 126Sn in nuclear waste samples. For the determination of non-actinide radionuclides in radioactive wastes, several methods have been recently introduced. This method is suitable for the separation of radionuclides 99Tc and 126Sn from acidic solutions. Samples after digestion were directly loaded in 2 mol·dm-3 HCl acid on a cation exchange resin and then on an anion exchange. They were eluted with HNO3. After elution, the eluted fractions were measured either by gamma spectrometry on an HPGe detector or liquid scintillation counter with high chemical recoveries for a short period of time. Activity concentrations of 126Sn were below minimum detectable activity (MDA) for each experiment. A new radioanalytical method for the sequential determination of 99Tc and 126Sn in radioactive concentrates has been developed and successfully applied. The main advantage of the method was the time required for the separation of radionuclides, which was only five hours, and single column separation for the determination of these radionuclides, which makes the method very effective and cheap.

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