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Ocular Irritation Testing
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
George P. Daston, F. E. Freeberg
The rabbit possesses secretory glands around the eye which are not present in humans, including the Harderian gland, and nictitan gland. These may alter the composition of the liquid film covering the surface of the eye, although the extent of such differences, or what effect they would have on chemical irritancy, are not known. Buehler and Newmann35 communicated that tear production in the rabbit is restricted relative to human responses, which could also retard the clearance of a toxicant from the eye, potentiating the irritant response. There is no empirical evidence in the literature to support or refute this observation, however.
Radiation Hormesis in Cancer
Published in T. D. Luckey, Radiation Hormesis, 2020
Hormesis, or a threshold for cancer incidence, was consistently found with low doses of ionizing radiation with 18,000 young adult mice.932–936 When 10 cGy gamma ray exposure from 137Cs was administered within 15 s, both sexes exhibited hormesis for all cancers except thymic lymphoma in females and the rudimentary third eyelid, the Harderian gland. However, the Harderian gland showed no increased cancer incidence with exposures <50 cGy. Thymic lymphoma incidence showed a threshold in each sex with acute 10 or 25 cGy exposure.936 When chronically exposed to a total of 50 cGy gamma rays, the same response was noted. An acute dose of 50 cGy exceeded the threshold for several types of cancer. Each sex showed an inverse correlation between acute gamma ray dose, 0 to 1 Gy, and total reticular tissue neoplasms, a category which includes thymic lymphoma, myeloid leukemia, and reticulum cell sarcoma. The decreased incidence of reticulum cell sarcoma was the major factor in this trend.
The Pineal Gland
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
Rats and hamsters possess the “harderian gland,” which is situated behind the lateral eyes in the orbital cavity. Although function is essentially unknown, removal causes a change in melatonin secretion, which implicates the pineal.216 It may thus be a segment of a retinal-pineal system.
Repeatability of Non-invasive Tear Film Evaluation in Healthy Rabbit Eyes
Published in Current Eye Research, 2023
Swati Singh, Saumya Srivastav, Minal Thacker, Kiran K. Bokara, Vivek Singh, Sayan Basu
The use of keratograph is different for rabbit eyes as K5M has only been validated for human eyes.8 The larger corneal surface and less bulbar conjunctival area preclude the use of an automatic bulbar redness scoring system. Nevertheless, an objective way of documenting pre- and post-experiment changes would make the animal experiments more reliable. There can be instances when NIBUT values are difficult to obtain. Rabbits have a thick lipid layer, hence the NIBUT values differ from human eyes. We observed that the rabbit meibomian glands are placed closely and have a wider diameter than human meibomian glands on meibography (Figure 2), though not measured quantitatively. The wider the gland, more is the acinar diameter, hence the lipid production would be more which might explain the increased NIBUT values in rabbits compared to humans. Also, Harderian glands in rabbit eyes contribute to the lipid layer of the tear film other than meibomian glands. However, the constituents of meibum would also affect the lipid layer thickness that are largely unknown for rabbits. The break-up patterns were unlike humans, lacking the complex interference patterns or wave formations observed in humans.9 Hence, lipid layer analysis was not performed on the keratograph.
Evaluation of acute and subacute toxicity of sodium taurodeoxycholate in rats
Published in Drug and Chemical Toxicology, 2021
Hyung Jun Choi, Jun-Won Yun, Youn-Hee Kim, Euna Kwon, Min-Kyong Hyon, Ji Young Kim, Jeong-Hwan Che, Woo Ho Kim, Seung-Yong Seong, Byeong-Cheol Kang
Macroscopic and histological assessments were performed as previously described (Yun et al.2017). At necropsy, organs were first evaluated macroscopically and collected after the last blood collection and exsanguination. After measurement of organ (liver, kidney, testis, ovary, thymus, heart, lung, spleen, brain, adrenal gland, and pituitary gland) weights, the eyes with the Harderian glands were fixed in Davidson's solution and the testis and epididymis were fixed in Bouin’s liquid for histopathological procedure. Other organs were immediately fixed in 10% formalin. Nasal tissues and femora were decalcified in a decalcification solution (6.5% nitiric acid solution) for 3 weeks. Then, hematoxylin and eosin (H&E)-stained sections were prepared from paraffin-embedded tissue samples. After staining, the slide glasses were examined with light microscopy (IX61, Olympus, Tokyo, Japan).
Lacrimal Gland and Orbital Lesions in LatY136F Knock-in Mice, a Model for Human IgG4-Related Ophthalmic Disease
Published in Current Eye Research, 2022
Shoko Hamaoka, Masayuki Takahira, Mitsuhiro Kawano, Kazunori Yamada, Kiyoaki Ito, Tetsuhiko Okuda, Sachiyo Hatake, Marie Malissen, Bernard Malissen, Kazuhisa Sugiyama
A macroscopic view of the lacrimal and Harderian glands dissected from a representative LatY136F knock-in mouse is shown in Figure 1. The extraorbital lacrimal gland is connected to the intraorbital lacrimal gland by a duct approximately 5 mm in length. The intraorbital lobe of the lacrimal gland is attached to the eyelid. The Harderian gland surrounds the eyeball in the orbit. In this study, the extraorbital lobes were used for the lacrimal gland samples.