The effect of triethylene melamine on DNA synthesis and mitosis in the lens epithelium

Sallmann, L.; Grimes, Patricia A.

doi:10.1007/bf00165400

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…Recently it was reported that a single injection of IPR resulted in an "inhibition" of mitosis 24 h after injection and a "stimulation" at 48 h in rat lens epithelium (4,5). The present report demonstrates that the results obtained from a single injection of I P R can be misleading without time series analysis.…”

Section: Introductionmentioning

confidence: 99%

Isoproterenol-Induced Phase Shifts in Circadian Rhythm of Mitosis in Murine Corneal Epithelium

Burns

Scheving

1973

The Journal of Cell Biology

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Section: Introductionmentioning

confidence: 99%

Isoproterenol-Induced Phase Shifts in Circadian Rhythm of Mitosis in Murine Corneal Epithelium

Burns

Scheving

1973

The Journal of Cell Biology

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“…MNU is also capable of acting as a methyl-group donor for glutathione and cysteine (36) and thus may produce protein adducts, although such findings have not been described. It has been suggested that alkylating agents are cataractogenic because of interference with cell proliferation (37) or gene expression (38). A determination of the type and persistence of adducts formed in the lens will be important to understanding how MNU induces cataracts.…”

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confidence: 99%

Protective effects of estrogen in a rat model of age-related cataracts

Bigsby

Cárdenas

Caperell-Grant

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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Women have a higher incidence of cataracts, and epidemiologic data suggest that the increased risk may be caused by a lack of estrogen in postmenopausal years. We have examined the effects of estrogen on methylnitrosourea (MNU)-induced cataractogenesis in Sprague-Dawley rats. Animals were ovariectomized, injected with MNU, and treated with estradiol or estrone by a continuous-release, subcutaneous Silastic implant, or they received an empty Silastic implant (no hormone). In the no-hormone group, rats developed opaque lenses approximately 6 months after MNU treatment. By 8 months, 74% (14͞19) of the no-hormone rats had evident opacity in one or both eyes by simple gross inspection; 58% (22͞38) of the eyes in this group were opaque. Estradiol or estrone treatment reduced the incidence of cataractous eyes to 12% or 25%, respectively. Lenses were examined under a dissecting microscope for light transmission. The lenses of the group treated with no hormone had light transmission of 26% ؎ 9.2%, whereas lenses from the estradiol-treated animals had light transmission of 72% ؎ 5.8%. Histological examination revealed that the anterior cortices of the opaque lenses were disrupted and showed the hallmark signs of age-related cataracts; in addition, some eyes that appeared clear by macroscopic examination showed the early histologic signs of cataractogenesis. It was demonstrated with reverse transcription-PCR that lens cells express both ␣ and ␤ types of estrogen receptor, suggesting that the protective effects of the hormones may be a direct, receptor-mediated phenomenon. Thus, the MNU-treated, ovariectomized rat serves as a model for age-related cataractogenesis, and observation of a clear protective effect of estrogens in this system supports the implications of epidemiologic data.More than 75% of people Ն75 years old have some degree of lens opacification (1), and it is estimated that Ͼ50% of blindness is caused by cataracts (2). Age-related cataracts can be classified according to their anatomic location within the lens: cortical, nuclear, posterior, or mixed (3). Women exhibit an increased incidence of cataracts compared with agematched men (4-7), mainly because of a higher rate of cortical cataracts (8, 9). Thus, age-related cataracts present a significant health problem, one that exhibits a sexual dichotomy.Epidemiologic evidence suggests that estrogens may protect against cataracts. Although women are at a higher risk of developing cataracts than are men, this increased risk comes after menopause, when estrogen levels have waned (9, 10). In one study of 544 women, early onset of menopause was associated with a 2.9-fold risk of developing cataracts (11). Moreover, the results of three small epidemiologic studies suggest that postmenopausal estrogen replacement therapy reduces the incidence of cataracts (12)(13)(14). The role of estrogen in modifying the onset of age-related cataractogenesis requires suitable experimental models for further study.Results of animal studies have produced conflicting observation...

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Tolérance aux antimitotiques introduits dans la chambre antérieure de l'œil du chat

Af¹

1974

Albrecht von Graefes Arch. Klin. Ophthalmol.

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The effect of triethylene melamine on DNA synthesis and mitosis in the lens epithelium

Cited by 9 publications

References 10 publications

Isoproterenol-Induced Phase Shifts in Circadian Rhythm of Mitosis in Murine Corneal Epithelium

Isoproterenol-Induced Phase Shifts in Circadian Rhythm of Mitosis in Murine Corneal Epithelium

Protective effects of estrogen in a rat model of age-related cataracts

Tolérance aux antimitotiques introduits dans la chambre antérieure de l'œil du chat

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