Hearing Protection Outcomes of Analog Electrode Arrays Coated with Different Drug-Eluting Polymer Films Implanted into Guinea Pig Cochleae [Corrigendum]

Following the huge clinical success of drug-eluting vascular stents, there is a significant interest in the development of drug-eluting stents for other applications, such as the treatment of gastrointestinal (GI) cancers. Central to this process is understanding how particular drugs are released from stent coatings, which to a large extent is controlled by drug-polymer interactions. Therefore, in this study we investigated the release of docetaxel (DTX) from a selection of non-degradable polymer films. DTX-polymer films were prepared at various loadings (1, 5 and 10% w/w) using three commercially available polymers including poly(dimethylsiloxane) (PSi), poly (ethylene-co-vinyl acetate) (PEVA) and Chronosil polyurethane (PU). The formulations were characterised using different techniques such as photoacoustic Fourier-transform infrared (PA-FTIR) spectrophotometry, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of DTX on the mechanical properties of the films, in-vitro release, and degradation tests were also assessed. For all polymers and DTX loadings, the drug was found to disperse homogenously without crystallisation within the polymer matrix. While no specific interactions were observed between DTX and PSi or PEVA, hydrogen-bonding appeared to be present between DTX and PU, which resulted in a concentration-dependent decrease in the Young’s moduli of the films due to disruption of inter-polymeric molecular interactions. In addition, the DTX-PU interactions were found to modulate drug release, providing near-linear release over 30 days, which was accompanied by a significant reduction in degradation products. The results indicate that DTX-loaded PU films are excellent candidates for drug-eluting stents for the treatment of oesophageal cancer.

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Decision letter for "The Effect of Optic Nerve Section on Form Deprivation Myopia in the Guinea Pig"

10.1002/cne.24961/v1/decision1 ◽

2020 ◽

Keyword(s):

Optic Nerve ◽

Guinea Pig ◽

Nerve Section

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Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080766 ◽

1977 ◽

Vol 35 ◽

pp. 668-669

Author(s):

Mai M. Said ◽

Ramesh K. Nayak ◽

Randall E. McCoy

Keyword(s):

Guinea Pig ◽

Reproductive Tract ◽

Three Dimensional ◽

Female Reproductive Tract ◽

Human Female ◽

Surface Ultrastructure ◽

Transmission Electron ◽

Sem Study ◽

Uterine Mucosa ◽

Group 1

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.

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Ultrastructure and Drug Metabolism in the Developing Guinea Pig

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073131 ◽

1973 ◽

Vol 31 ◽

pp. 538-539

Author(s):

W. Kuenzig ◽

M. Boublik ◽

J.J. Kamm ◽

J.J. Burns

Keyword(s):

Guinea Pig ◽

Metabolic Activity ◽

Animal Species ◽

Adult Animal ◽

Smooth Endoplasmic Reticulum ◽

Fetal Life ◽

Mixed Function Oxidase ◽

Cytochrome P 450 ◽

Microsomal Mixed Function Oxidase ◽

Mixed Function Oxidase Activity

Unlike a variety of other animal species, such as the rabbit, mouse or rat, the guinea pig has a relatively long gestation period and is a more fully developed animal at birth. Kuenzig et al. reported that drug metabolic activity which increases very slowly during fetal life, increases rapidly after birth. Hepatocytes of a 3-day old neonate metabolize drugs and reduce cytochrome P-450 at a rate comparable to that observed in the adult animal. Moreover the administration of drugs like phenobarbital to pregnant guinea pigs increases the microsomal mixed function oxidase activity already in the fetus.Drug metabolic activity is, generally, localized within the smooth endoplasmic reticulum (SER) of the hepatocyte.

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Glycogen in guinea pig neutrophils: Ultrastructural study of neutrophils at the intradermal site of BCG injection

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077207 ◽

1983 ◽

Vol 41 ◽

pp. 726-727

Author(s):

Corazon D. Bucana

Keyword(s):

Bone Marrow ◽

Guinea Pig ◽

Electron Density ◽

Peritoneal Cavity ◽

Ultrastructural Study ◽

Guinea Pigs ◽

Random Distribution ◽

Glycogen Content ◽

Polymorphonuclear Neutrophils ◽

Ultrastructural Studies

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.

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Ultrastructural Studies on Genital Infection with the Chlamydial Agent of Guinea Pig Inclusion Conjunctivitis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079267 ◽

1977 ◽

Vol 35 ◽

pp. 352-353

Author(s):

B. L. Soloff ◽

A. L. Barron ◽

H. J. White ◽

R. G. Rank

Keyword(s):

Guinea Pig ◽

Sexual Contact ◽

Chlamydia Psittaci ◽

Genital Infection ◽

Major Site ◽

Ultrastructural Studies ◽

Tissue Specimens ◽

Guinea Pig Model ◽

Adequate Tissue ◽

Genital Tissue

Chlamydial organisms (specifically C. trachomatis) have been implicated as a frequent cause of genital infection in the human (1). Study of the histo- pathological aspects of such infections has been impeded because of difficulties in obtaining adequate tissue specimens and the lack of a suitable experimental host. In 1964, Murray (2) isolated the causative agent of guinea pig inclusion conjunctivitis which possesses similarities to human inclusion conjunctivitis. This guinea pig organism was found to be a member of the Chlamydia psittaci subgroup and was designated as the Gp-ic agent. Male guinea pigs have been successfully infected with Gp-ic by intraurethral inoculation. Transmission of the infection to the female by sexual contact has been demonstrated (3). We are not aware of any ultrastructural studies to date concerning the development of this agent in genital tissue.Studies in our laboratory have established that, in our guinea pig model, the cervix is the major site of injection.

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Ultrastructural and chemical evidences of heterogeneity and hormone dependence of certain glycocalyces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082479 ◽

1978 ◽

Vol 36 (2) ◽

pp. 322-323

Author(s):

B. Monis ◽

D. Lis ◽

I. Parlanti ◽

A. R. Eynard ◽

M. A. Valentich ◽

...

Keyword(s):

Guinea Pig ◽

Concanavalin A ◽

Ruthenium Red ◽

Transitional Epithelium ◽

Membrane Material ◽

Hormone Dependence ◽

Cellulose Acetate Electrophoresis ◽

Electrophoretic Data ◽

Fat Globule ◽

Collecting Tubules

We are gathering evidences which indicate ultrastructural variations and chemical heterogeneity of certain glycocalyces as well as hormone dependence of some of them. Thus, in the lumenal glycocalyx of renal collecting tubules of the guinea-pig granular and filamentous structures were seen (1, fig. 1). By isolation, chemical analysis and cellulose acetate electrophoresis in various buffers of tubular membrane material, glycopeptides and glycosaminoglycans were identified (fig. 2).Guinea-pig and rat transitional epithelium of urinary tract showed a filamentous lumenal glycocalyx demonstrable with ruthenium red (fig. 3) but which only in part stained with concanavalin A. Chemical and electrophoretic data indicated that urothelium contains glycoproteins, glycosaminoglycans and glycolipids.The glycocalyx of the fat globule membrane of milk of several species has a granular appearance as shown by cationic dyes and by concanavalin A (2, 3, fig. 4 and 5). Also, several glycoproteins were isolated and identified on polyacrilamide gel electrophoresis (fig. 6). Glycosaminoglycans and certain glycolipids such as sulfatides were chemically identified in this glycocalyx.

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Cell Reactivity Pattern of the Guinea Pig Cecal Mucosa Evidenced by the ZIO Technique

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005305x ◽

1982 ◽

Vol 40 ◽

pp. 50-51

Author(s):

Juan Mora-Galindo ◽

Jorge Arauz-Contreras

Keyword(s):

Guinea Pig ◽

Phase Contrast ◽

Osmium Tetroxide ◽

Cell Types ◽

Cell Reactivity ◽

Transmission Electron ◽

Neural Tissues ◽

Maturation Stages ◽

Zinc Iodide ◽

Cecal Mucosa

The zinc iodide-osmium tetroxide (ZIO) technique is presently employed to study both, neural and non neural tissues. Precipitates depends on cell types and possibly cell metabol ism as well.Guinea pig cecal mucosa, already known to be composed of epithelium with cells at different maturation stages and lamina propria which i s formed by morphologically and functionally heterogeneous cell population, was studied to determine the pat tern of ZIO impregnation. For this, adult Guinea pg cecal mucosa was fixed with buffered 1.2 5% g 1 utara 1 dehyde before incubation with ZIO for 16 hours, a t 4°C in the dark. Further steps involved a quick sample dehydration in graded ethanols, embedding in Epon 812 and sectioning to observe the unstained material under a phase contrast light microscope (LM) and a transmission electron microscope (TEM).

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