scholarly journals Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

2020 ◽  
Author(s):  
Xinyan Chen ◽  
Xiao Qin ◽  
Mengyao Yu ◽  
Haixia Zhang ◽  
Lin Li
Keyword(s):  
Elastic Modulus ◽  
Negative Pressure ◽  
Morphological Changes ◽  
Corneal Thickness ◽  
Central Zone ◽  
Large Individual ◽  
Type Ii ◽  
The Third ◽  
Short Period

Abstract Background To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment. Method Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. In group NP, the corneas were continuously attracted by negative pressure with 500 mmHg for 30 min, treated by every other day, three times in total. In group CII, the corneal central zone was soaked in the collagenase type II solution (200 μL of 3 mg/ml) for 30 min. In group CP, the corneas were disposed as group CII firstly, then applied negative pressure as group NP for once after 5 days. All right eyes were treated as control eyes. Corneal morphology and biomechanical related parameters were observed in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment. Results Corneal diopter and corneal central thickness (CCT) changed to some extent after treatment immediately as a result of negative pressure in group NP. The corneas in Group NP had smaller elastic modulus and slower relaxation degree compared with the control one 3 months after treatment. In Group CII, corneal diopter increased, CCT and CH decreased at the second week after treatment, which showed the characters of ectatic corneas. At the third month after treatment, elastic modulus (EL) of the experimental eyes decreased slightly compared with the control eyes. Due to the large individual differences, there were no regular changes on experimental corneas in Group CP. Conclusions Cornea socked with collagenase type II showed the obvious characteristics of ectatic cornea at the second week after treatment, but the characteristics disappeared gradually. Negative pressure can result in the change of corneal thickness and diopter in a short period of time, and the degree of swelling and duration are far less than Group CII, but the changes of biomechanical parameters are more obviously than Group CII.

scholarly journals Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

2020 ◽  
Author(s):  
Xinyan Chen ◽  
Xiao Qin ◽  
Mengyao Yu ◽  
Haixia Zhang ◽  
Lin Li
Keyword(s):  
Elastic Modulus ◽  
Negative Pressure ◽  
Morphological Changes ◽  
Corneal Thickness ◽  
Central Zone ◽  
Large Individual ◽  
Type Ii ◽  
The Third ◽  
Short Period

Abstract Background: To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment.Method: Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. In group NP, the corneas were continuously attracted by negative pressure with 500 mmHg for 30 min, treated by every other day, three times in total. In group CII, the corneal central zone was soaked in the collagenase type II solution (200 μL of 3 mg/ml) for 30 min. In group CP, the corneas were disposed as group CII firstly, then applied negative pressure as group NP for once after 5 days. All right eyes were treated as control eyes. Corneal morphology and biomechanical related parameters were observed in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment.Results: Corneal diopter and corneal central thickness (CCT) changed to some extent after treatment immediately as a result of negative pressure in group NP. Three months after treatment, their elastic modulus increased and the relaxation degree decreased compared with the control one. In Group CII, corneal diopter increased, CCT and CH decreased at the second week after treatment, which showed the characters of ectatic corneas. At the third month after treatment, elastic modulus (E L ) of the experimental eyes decreased slightly compared with the control eyes. Due to the large individual differences, there were no regular changes on experimental corneas in Group CP.Conclusions: Cornea socked with collagenase type II showed the obvious characteristics of ectatic cornea at the second week after treatment, but the characteristics disappeared gradually. Negative pressure can result in the change of corneal thickness and diopter in a short period of time, and the degree of swelling and duration are far less than Group CII, but the changes of biomechanical parameters are more obviously than Group CII.

scholarly journals Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

2020 ◽  
Author(s):  
Xinyan Chen ◽  
Xiao Qin ◽  
Mengyao Yu ◽  
Haixia Zhang ◽  
Lin Li
Keyword(s):  
Elastic Modulus ◽  
Negative Pressure ◽  
Repeated Measures ◽  
Morphological Changes ◽  
Corneal Thickness ◽  
Central Area ◽  
Type Ii ◽  
Short Period ◽  
Significant Difference ◽  
Pressure Suction

Abstract Background To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment. Method Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. The left corneas were continuously treated by negative pressure suction (NP group) with 500 mmHg for 30 min once two days, three times in total. The central area of left corneas were soaked in the collagenase type II (CII group) solution (200 μL of 3 mg/ml) for 30 min. The left corneas (CP group) were disposed as CII group firstly, then applied negative pressure suction as NP group for once after 5 days. All right corneas were treated as control eyes. Corneal morphology parameters and Ocular Response Analyzer (ORA) output parameters were collected in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment. Paired t-test and repeated measures analysis were used to determine if there were differences in biomechanical and morphological related parameters across time. Results In NP group, corneal thickness and diopter changed to some extent after treatment immediately, and the elastic modulus increased and relaxation degree slowed after 3 months. In CII group, corneal diopter increased, corneal central thickness (CCT) and corneal hysteresis (CH) decreased at the second week after treatment, which showed the characters of ectatic corneas. Then the degree of ectasia decreased with time. No regular changes was found on experimental corneas in CP group. Conclusions Collagenase type II results in ectatic corneas around two weeks after treatment, but the degree of ectasia decreased with time, and there was no significant difference compared with the controls after 3 months. After negative pressure suction, corneal morphology changed in a short period, and elastic modulus increased and relaxation time increased after a three months recovery, indicating that the negative pressure suction do have a certain effect on corneas.

scholarly journals Relationship between Aldose reductase and superoxide dismutase inhibition capacities of indole-based analogs of melatonin derivatives

2009 ◽  
Vol 61 (4) ◽  
pp. 675-681 ◽  
Author(s):  
N. Daş-Evcimen ◽  
Ö. Yildirim ◽  
S. Suzen
Keyword(s):  
Aldose Reductase ◽  
Diabetic Complications ◽  
Morphological Changes ◽  
Antioxidant Properties ◽  
Polyol Pathway ◽  
Antioxidant Enzyme Activity ◽  
Indole Derivatives ◽  
The Third ◽  
The Relationship

Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Under diabetic conditions, the elevated vascular glucose level causes an increased flux through the polyol pathway, which induces functional and morphological changes associated with secondary diabetic complications such as cataract, neuropathy, and nephrop?athy. Oxidative stress, antioxidants, and the polyol pathway have recently been found to be linked in pathological states. A large number of structurally different compounds have been studied as potent in vitro AR inhibitors (ARIs). However, with few exceptions, these compounds did not show clinical benefit, and some even produced serious side effects. In view of the ARI activity of certain indole derivative compounds and antioxidant properties of melatonin, we investigated some indole-based analogs of melatonin derivatives. Antioxidant and ARI activity tests were applied to nine indole derivatives that are substituted at the third and fifth positions. Also, the relationship between ARI and antioxidant enzyme activity is discussed.

The development of Haemonchus contortus in vitro: II. The effect of disulphide-reducing and sulphydryl-blocking reagents on the rate of development to the fourth-stage larvae

Parasitology ◽  
1970 ◽  
Vol 60 (1) ◽  
pp. 123-135 ◽  
Author(s):  
C. J. Mapes
Keyword(s):  
Haemonchus Contortus ◽  
Reduced Glutathione ◽  
Stage Larva ◽  
Fourth Stage ◽  
Rate Of Development ◽  
The Third ◽  
Short Period ◽  
Third Stage ◽  
Before And After

Cysteine (20–100 mM) and reduced glutathione (20–80 mM) potentiated the development of the exsheathed third-stage larva of Haemonchus contortus to the fourth stage. The potentiating effect of cysteine was greatest during the short period before and after the exsheathment of the third-stage larva. Two hundred mM cysteine and 1 mM p–chloro-benzoate inhibited development. This inhibition was reversible. Ten mM iodoacetate and 0·5 and 5 mM n–ethyl-maleimide inhibited development of the larvae. The larvae appeared to be most susceptible to the inhibiting effects of these reagents during the period of development approaching the third moult. Development was either little affected or potentiated, when larvae were incubated with these reagents for short periods immediately after exsheathment.

Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

1975 ◽  
Vol 33 ◽  
pp. 600-601
Author(s):  
John C. Garancis ◽  
Robert O. Hussa ◽  
Michael T. Story ◽  
Donald Yorde ◽  
Roland A. Pattillo
Keyword(s):  
Electron Microscopy ◽  
Cellular Proliferation ◽  
Morphological Changes ◽  
Culture Fluid ◽  
Cellular Functions ◽  
Human Trophoblast ◽  
Transmission Electron ◽  
Marked Activity ◽  
Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

Increased Protein Synthesis by Human Platelets during Phagocytosis of Latex Particles in Vitro

1976 ◽  
Vol 35 (02) ◽  
pp. 350-357 ◽  
Author(s):  
Hana Bessler ◽  
Galila Agam ◽  
Meir Djaldetti
Keyword(s):  
Protein Synthesis ◽  
Fold Increase ◽  
Human Platelets ◽  
Polystyrene Latex ◽  
Latex Particles ◽  
The Third ◽  
Platelet Protein ◽  
Dose Dependent ◽  
Phagocytotic Activity

SummaryA three-fold increase of protein synthesis by human platelets during in vitro phagocytosis of polystyrene latex particles was detected. During the first two hours of incubation, the percentage of phagocytizing platelets and the number of latex particles per platelet increased; by the end of the third hour, the first parameter remained stable, while the number of latex particles per cell had decreased.Vincristine (20 μg/ml of cell suspension) inhibited platelet protein synthesis. This effect was both time- and dose-dependent. The drug also caused a decrease in the number of phagocytizing cells, as well as in their phagocytotic activity.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

Significance of In-Vitro and In-Vivo Correlation in Drug Delivery System

2018 ◽  
Vol 4 (4) ◽  
pp. 523-531
Author(s):  
Hina Mumtaz ◽  
Muhammad Asim Farooq ◽  
Zainab Batool ◽  
Anam Ahsan ◽  
Ashikujaman Syed
Keyword(s):  
Dosage Form ◽  
Pharmaceutical Preparations ◽  
Pharmacokinetic Profile ◽  
In Vitro Dissolution ◽  
Time Saving ◽  
Pharmaceutical Dosage Form ◽  
Short Period ◽  
Form Development

The main purpose of development pharmaceutical dosage form is to find out the in vivo and in vitro behavior of dosage form. This challenge is overcome by implementation of in-vivo and in-vitro correlation. Application of this technique is economical and time saving in dosage form development. It shortens the period of development dosage form as well as improves product quality. IVIVC reduce the experimental study on human because IVIVC involves the in vivo relevant media utilization in vitro specifications. The key goal of IVIVC is to serve as alternate for in vivo bioavailability studies and serve as justification for bio waivers. IVIVC follows the specifications and relevant quality control parameters that lead to improvement in pharmaceutical dosage form development in short period of time. Recently in-vivo in-vitro correlation (IVIVC) has found application to predict the pharmacokinetic behaviour of pharmaceutical preparations. It has emerged as a reliable tool to find the mode of absorption of several dosage forms. It is used to correlate the in-vitro dissolution with in vivo pharmacokinetic profile. IVIVC made use to predict the bioavailability of the drug of particular dosage form. IVIVC is satisfactory for the therapeutic release profile specifications of the formulation. IVIVC model has capability to predict plasma drug concentration from in vitro dissolution media.

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