scholarly journals STUDIES ON THE CORNEA

1962 ◽  
Vol 12 (3) ◽  
pp. 457-479 ◽  
Author(s):  
Gordon I. Kaye ◽  
George D. Pappas
Keyword(s):  
Iron Oxide ◽  
Anterior Chamber ◽  
Aqueous Humor ◽  
Colloidal Particles ◽  
Corneal Stroma ◽  
Thorium Dioxide ◽  
Large Molecules ◽  
To Receive ◽  
Magnification Level

Physiological studies have demonstrated that ions, as well as large molecules such as hemoglobin or fluorescein, can diffuse across and within the cornea. Most of the substrates for corneal metabolism are obtained from aqueous humor filling the anterior chamber. In order to receive its nutrients and in order to maintain its normal conditions of hydration, the avascular cornea must transport relatively large amounts of solute and solvent across the cellular layers which cover this structure. It has been suggested in the past that there may be a morphological basis for the transport of large amounts of solvents and solutes by cells by the mechanism of pinocytosis. The use of electron-opaque markers to study fluid movements at the electron microscope magnification level was described by Wissig (29). The present study describes the fine structure of the normal rabbit cornea and the pathways of transport of colloidal particles by the cornea in vivo. Rabbit corneas were exposed in vivo to suspensions of saccharated iron oxide, thorium dioxide, or ferritin by injection of the material into the anterior chamber. In other experiments thorium dioxide or saccharated iron oxide was injected into the corneal stroma, producing a small bleb. Particles presented at the aqueous humor surface of the rabbit corneal endothelium are first attached to the cell surface and then pinocytosed. It appears that the particles are carried around the terminal bar by an intracellular pathway involving the pinocytosis of the particles and their subsequent transport in vesicles to the lateral cell margin basal to the terminal bar. Particles introduced at the basal surface of the endothelium (via blebs in the corneal stroma) are apparently carried through the endothelial cells in membrane-bounded vesicles without appearing in the intercellular space. There appears to be free diffusion of these particles through Descemet's membrane and the corneal stroma. The stromal cells take up large quantities of the particles when blebs are injected into the stroma.

scholarly journals STUDIES ON THE CORNEA

1962 ◽  
Vol 12 (3) ◽  
pp. 481-501 ◽  
Author(s):  
Gordon I. Kaye ◽  
George D. Pappas ◽  
Anthony Donn ◽  
Nancy Mallett
Keyword(s):  
Colloidal Particles ◽  
Corneal Stroma ◽  
Apical Surface ◽  
Transport Activity ◽  
Experimental Conditions ◽  
Thorium Dioxide ◽  
Endothelial Surface ◽  
Lateral Cell

In vitro studies of the transport of colloidal particles by the cornea were carried out on intact corneas of adult rabbits in a chamber described by Donn, Maurice, and Mills (2) in which the epithelial or the endothelial surface of the cornea was exposed to thorium dioxide or saccharated iron oxide under various conditions. These studies confirmed the results of previous work in vivo and allowed modification of the experimental conditions. Particles are pinocytosed at the apical surface of the corneal endothelium and carried around the terminal bar in membrane-bounded vesicles. Basal to the terminal bar these vesicles fuse with the lateral cell margin and their contents are released into the intercellular space, in which they appear to be carried by a one-way flow down to Descemet's membrane and the corneal stroma. Indications that the endothelial transport is an active process are presented by the different pathways of transport into or out of the corneal stroma, as well as by the approximately 70 per cent reduction in transport activity at low temperatures.

scholarly journals Synthesis, Principles, and Properties of Magnetite Nanoparticles for In Vivo Imaging Applications—A Review

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 601 ◽  
Author(s):  
Wallyn ◽  
Anton ◽  
Vandamme
Keyword(s):  
Iron Oxide ◽  
Targeted Delivery ◽  
Biomedical Applications ◽  
Colloidal Particles ◽  
Chemical Properties ◽  
Local Drug Delivery ◽  
Physical And Chemical ◽  
Immense Potential ◽  
Drug Nanocarriers

The current nanotechnology era is marked by the emergence of various magnetic inorganic nanometer-sized colloidal particles. These have been extensively applied and hold an immense potential in biomedical applications including, for example, cancer therapy, drug nanocarriers (NCs), or in targeted delivery systems and diagnosis involving two guided-nanoparticles (NPs) as nanoprobes and contrast agents. Considerable efforts have been devoted to designing iron oxide NPs (IONPs) due to their superparamagnetic (SPM) behavior (SPM IONPs or SPIONs) and their large surface-to-volume area allowing more biocompatibility, stealth, and easy bonding to natural biomolecules thanks to grafted ligands, selective-site moieties, and/or organic and inorganic corona shells. Such nanomagnets with adjustable architecture have been the topic of significant progresses since modular designs enable SPIONs to carry out several functions simultaneously such as local drug delivery with real-time monitoring and imaging of the targeted area. Syntheses of SPIONs and adjustments of their physical and chemical properties have been achieved and paved novel routes for a safe use of those tailored magnetic ferrous nanomaterials. Herein we will emphasis a basic notion about NPs magnetism in order to have a better understanding of SPION assets for biomedical applications, then we mainly focus on magnetite iron oxide owing to its outstanding magnetic properties. The general methods of preparation and typical characteristics of magnetite are reviewed, as well as the major biomedical applications of magnetite.

The transport of particles across the walls of small blood vessels

1962 ◽  
Vol 156 (962) ◽  
pp. 14-19 ◽  
Keyword(s):  
Iron Oxide ◽  
Blood Vessels ◽  
Rat Heart ◽  
Colloidal Particles ◽  
Perivascular Spaces ◽  
Thorium Dioxide ◽  
Perfused Rat Heart

Colloidal particles of thorium dioxide and saccharated iron oxide and molecules of ferritin enter the vesicles of the endothelium of the perfused rat heart. The first two substances have been shown to pass within the vesicles through the cells of the endothelium into the perivascular spaces.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

1994 ◽  
Vol 72 (06) ◽  
pp. 942-946 ◽  
Author(s):  
Raffaele Landolfi ◽  
Erica De Candia ◽  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Armando Antinori ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Primary Source ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Heparin Administration ◽  
To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

Clearance rate in relation to agglutinins for gelatin-stabilized colloid in the rat

1963 ◽  
Vol 204 (4) ◽  
pp. 655-659 ◽  
Author(s):  
I. MacKay Murray
Keyword(s):  
Iron Oxide ◽  
Clearance Rate ◽  
Reticuloendothelial System ◽  
Transient Increase ◽  
Clearance Rates ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Plasma Response ◽  
Circulating Levels

Intravascular clearance rates of gelatin-stabilized gold were compared with circulating titers of gelatin agglutinins in rats at increasing time intervals after blockading injections of gelatin-stabilized gold and S. marcescens endotoxin. The degree and duration of reticuloendothelial system (RES) blockade against the homologous colloid were directly related to the circulating levels of gelatin agglutinins. In contrast, plasma agglutinins were not decreased in endotoxin-induced blockade against the gelatin-stabilized colloid. In a further experiment, the plasma response to blockading injections of colloidal thorium dioxide, iron oxide, and zymosan was characterized by a transient increase in gelatin agglutinins suggesting the nonspecific release of opsonins from an extravascular source. The findings indicated that clearance rates of gelatin-stabilized colloids were dependent on the total available opsonin in the rat rather than the total circulating opsonin. It is suggested that RES blockade is effected by the prior nonspecific depletion of opsonins from an extravascular reserve which is the major component of the total available opsonin.

scholarly journals Altered Expression Levels of MMP1, MMP9, MMP12, TIMP1, and IL-1βas a Risk Factor for the Elevated IOP and Optic Nerve Head Damage in the Primary Open-Angle Glaucoma Patients

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Lukasz Markiewicz ◽  
Dariusz Pytel ◽  
Bartosz Mucha ◽  
Katarzyna Szymanek ◽  
Jerzy Szaflik ◽  
...  
Keyword(s):  
Risk Factor ◽  
Aqueous Humor ◽  
Open Angle Glaucoma ◽  
Luciferase Assay ◽  
Control Group ◽  
Promoter Regions ◽  
Altered Expression ◽  
Expression Levels ◽  
The Impact

The aim of presented work was to analyze the impact of particular polymorphic changes in the promoter regions of the -1607 1G/2GMMP1, -1562 C/TMMP9, -82 A/GMMP12, -511 C/TIL-1β, and 372 T/CTIMP1genes on their expression level in POAG patients. Blood and aqueous humor samples acquired from 50 patients with POAG and 50 control subjects were used for QPCR and protein levels analysis by ELISA.In vivopromoter activity assays were carried on HTM cells using dual luciferase assay. All studied subjects underwent ophthalmic examination, including BCVA, intraocular pressure, slit-lamp examination, gonioscopy, HRT, and OCT scans. Patients with POAG are characterized by an increased mRNA expression ofMMP1,MMP9,MMP12, andIL-1βgenes as compared to the control group (P<0.001). Aqueous humor acquired from patients with POAG displayed increased protein expression of MMP1, MMP9, MMP12, and IL-1βcompared to the control group (P<0.001). Allele -1607 1G ofMMP1gene possesses only 42,91% of the -1607 2G allele transcriptional activity and allele -1562 C ofMMP9gene possesses only 21,86% of the -1562 T allele. Increased expression levels of metalloproteinases can be considered as a risk factor for the development of POAG.

scholarly journals Comparison of different techniques for estimating rates of protein synthesis in vivo in healthy and bacteraemic rats

1985 ◽  
Vol 226 (1) ◽  
pp. 37-42 ◽  
Author(s):  
J J Pomposelli ◽  
J D Palombo ◽  
K J Hamawy ◽  
B R Bistrian ◽  
G L Blackburn ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Rectus Muscle ◽  
Stochastic Modelling ◽  
Whole Body ◽  
Constant Infusion ◽  
Second Phase ◽  
Sprague Dawley ◽  
Body Protein ◽  
To Receive

Previous studies have reported that use of a flooding dose of radiolabelled amino acid is a more precise technique than the constant infusion of tracer quantities for determining rates of protein synthesis in rapidly turning-over tissues in the rat. However, there has been little direct investigation comparing different methods under comparable conditions. Initially, 12 healthy male Sprague-Dawley rats, weighing approx. 100 g, were randomized to receive either a bolus intravenous injection of 100 mumol of L-leucine (containing 30 microCi of [1-14C]leucine)/100 g body wt., or a continuous 2 h tracer infusion of [14C]leucine. In the second phase of the experiment, 12 additional rats were intravenously injected with 1 × 10(8) colony-forming units of Pseudomonas aeruginosa and 16 h later randomized to receive one of two infusions described above. Total protein synthesis as well as fractional synthesis rates were determined in liver, rectus muscle and whole body. Synthesis rates measured in liver, muscle and whole body were significantly higher in bacteraemic rats than in healthy rats. The flooding-dose methodology gave significantly higher estimates of protein synthesis in the liver, skeletal muscle and whole body than did the continuous-infusion method using direct measurement of the acid-soluble fraction from the respective tissue. Indirect estimates of whole-body protein synthesis based on plasma enrichments and stochastic modelling gave the lowest values.

Magnetic targeting with superparamagnetic iron oxide nanoparticles for in vivo glioma

2017 ◽  
Vol 6 (5) ◽  
pp. 449-472 ◽  
Author(s):  
Marina Fontes de Paula Aguiar ◽  
Javier Bustamante Mamani ◽  
Taylla Klei Felix ◽  
Rafael Ferreira dos Reis ◽  
Helio Rodrigues da Silva ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Process Efficiency ◽  
Cochrane Library ◽  
Oxide Nanoparticles ◽  
Magnetic Targeting

AbstractThe purpose of this study was to review the use of the magnetic targeting technique, characterized by magnetic driving compounds based on superparamagnetic iron oxide nanoparticles (SPIONs), as drug delivery for a specific brain locus in gliomas. We reviewed a process mediated by the application of an external static magnetic field for targeting SPIONs in gliomas. A search of PubMed, Cochrane Library, Scopus, and Web of Science databases identified 228 studies, 23 of which were selected based on inclusion criteria and predetermined exclusion criteria. The articles were analyzed by physicochemical characteristics of SPIONs used, cell types used for tumor induction, characteristics of experimental glioma models, magnetic targeting technical parameters, and analysis method of process efficiency. The study shows the highlights and importance of magnetic targeting to optimize the magnetic targeting process as a therapeutic strategy for gliomas. Regardless of the intensity of the patterned magnetic field, the time of application of the field, and nanoparticle used (commercial or synthesized), all studies showed a vast advantage in the use of magnetic targeting, either alone or in combination with other techniques, for optimized glioma therapy. Therefore, this review elucidates the preclinical and therapeutic applications of magnetic targeting in glioma, an innovative nanobiotechnological method.

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