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Development of corneal transparency in embryonic chick: Influence of exogenous thyroxine and thiouracil on structure, water and electrolyte content
228
Surv Ophthalmol
20 (3) November-December,
1975
over the age of sixty who died with senile dementia (Schwartz, Tram NY Acad Sci 27:393, 1965). Amyloid has been implicated as the cause of lattice degeneration of the cornea and other primary hereditary cornea1 degenerations, and it is present in the ciliary bodies of many aged individuals including those with pseudoexfoliation syndrome. Indeed at one time we felt (Henkind and Friedman, unpublished data) that the pseudoexfoliative
CURRENT
OPHTHALMOLOGY
material might contain amyloid. In retrospect, we were probably detecting a fairly common (“normal?“) aging change. Cohen (N Engl J Med 277.522-530, 574-583, 628-638, 1967) provides an excellent review of this
very complicated subject. I expect that we will hear much more about amyloid in the eye within the next few years. PAUL HENKIND
Development of Cornea1 Transparency in Embryonic Chick: Influence of Exogenous Thyroxine and Thiouracil on Structure, Water and Electrolyte Content, by E Masterson, HF Edelhauser and DL van Horn. Dev Biol 43:233-239, 1975 Thyroxine (T,) and thiouracil were injected into the extra-embryonic circulation of chick embryos at various developmental stages to determine their effects on cornea1 cellularity, dehydration and structure. Corneas were removed 2-9 days after treatment for analysis of (Na+) and (K+) concentration, water content and histological structure. In normal chick corneas, water content and (Na+) concentration decreased with advancing embryonic age, whereas (K+) increased up to stage 42 and then rapidly declined. Corneas from embryos injected with 10 pg thiouracil at stage 36 had significantly reduced (K+) at stages 40 and 42. Corneas at stages 40,42 and 45 had a significantly elevated water content as compared to controls. Injection of 15 rg of T, prior to stage 36 or at stage 40 or later did not produce significant changes in water and ionic content as compared to control cornea1 levels. In contrast, injection of 15 Fg of T, during the period of rapid cell proliferation (stages 36-40) produced a significant increase in cornea1 (K+) levels. Histological analysis revealed a total increase in cornea1 thickness following thiouracil
Cerebrospinal
treatment and a decrease in cornea1 thickness following T, treatment. Epithelial growth was reduced in thiouracil treatment while T, had little effect. Comment It is well known that the water content of the cornea is high in the early embryo, but decreases as development proceeds. Concomitant with this dehydration, the cornea achieves transparency. It has been demonstrated that cornea1 hydration is influenced by thyroid hormone (Coulombre and Coulombre, Exp Eye Res 3: 105, 1964). This paper extends these earlier observations by treating chick embryos with excess thyroxine and thiouracil, an inhibitor of thyroid function and then measuring cornea1 thickness, water and ion content. They suggest that thiouracil treatment decreases cell division in the cornea and orevents the formation of the epithelial barrier whereas thyroxine accelerates these processes. 1
JOE G HOLLYFIELD
Fluid in 25 Cases of Optic Neuritis, by M Sandberg and H Bynke.
Acta New-01 &and 49:443-452,
1973
Occurrence of cerebrospinal fluid changes (CSF) in monosymptomatic optic neuritis patients have been thought to serve as a possible indicator of future development of multiple sclerosis. Such changes include mononuclear pleocytosis, increase in total protein and relative immunoglobin G (IgG) concentration, varying numbers of discrete IgG bonds in the gamma globulin fraction on agar gel electrophoresis and a possible abnormal dis-
tribution of kappa and lambda antigenic determinants in immunodiffusion and on immunoelectrophoresis. Twenty-five patients with acute monosymptomatic optic neuritis were studied for changes in the CSF as a possible indicator of future development of multiple sclerosis. After ocular and neurological examinations, the patients were subjected to cytological examinations, determinations
Surv Ophthalmol
20 (3) November-December,
1975
over the age of sixty who died with senile dementia (Schwartz, Tram NY Acad Sci 27:393, 1965). Amyloid has been implicated as the cause of lattice degeneration of the cornea and other primary hereditary cornea1 degenerations, and it is present in the ciliary bodies of many aged individuals including those with pseudoexfoliation syndrome. Indeed at one time we felt (Henkind and Friedman, unpublished data) that the pseudoexfoliative
CURRENT
OPHTHALMOLOGY
material might contain amyloid. In retrospect, we were probably detecting a fairly common (“normal?“) aging change. Cohen (N Engl J Med 277.522-530, 574-583, 628-638, 1967) provides an excellent review of this
very complicated subject. I expect that we will hear much more about amyloid in the eye within the next few years. PAUL HENKIND
Development of Cornea1 Transparency in Embryonic Chick: Influence of Exogenous Thyroxine and Thiouracil on Structure, Water and Electrolyte Content, by E Masterson, HF Edelhauser and DL van Horn. Dev Biol 43:233-239, 1975 Thyroxine (T,) and thiouracil were injected into the extra-embryonic circulation of chick embryos at various developmental stages to determine their effects on cornea1 cellularity, dehydration and structure. Corneas were removed 2-9 days after treatment for analysis of (Na+) and (K+) concentration, water content and histological structure. In normal chick corneas, water content and (Na+) concentration decreased with advancing embryonic age, whereas (K+) increased up to stage 42 and then rapidly declined. Corneas from embryos injected with 10 pg thiouracil at stage 36 had significantly reduced (K+) at stages 40 and 42. Corneas at stages 40,42 and 45 had a significantly elevated water content as compared to controls. Injection of 15 rg of T, prior to stage 36 or at stage 40 or later did not produce significant changes in water and ionic content as compared to control cornea1 levels. In contrast, injection of 15 Fg of T, during the period of rapid cell proliferation (stages 36-40) produced a significant increase in cornea1 (K+) levels. Histological analysis revealed a total increase in cornea1 thickness following thiouracil
Cerebrospinal
treatment and a decrease in cornea1 thickness following T, treatment. Epithelial growth was reduced in thiouracil treatment while T, had little effect. Comment It is well known that the water content of the cornea is high in the early embryo, but decreases as development proceeds. Concomitant with this dehydration, the cornea achieves transparency. It has been demonstrated that cornea1 hydration is influenced by thyroid hormone (Coulombre and Coulombre, Exp Eye Res 3: 105, 1964). This paper extends these earlier observations by treating chick embryos with excess thyroxine and thiouracil, an inhibitor of thyroid function and then measuring cornea1 thickness, water and ion content. They suggest that thiouracil treatment decreases cell division in the cornea and orevents the formation of the epithelial barrier whereas thyroxine accelerates these processes. 1
JOE G HOLLYFIELD
Fluid in 25 Cases of Optic Neuritis, by M Sandberg and H Bynke.
Acta New-01 &and 49:443-452,
1973
Occurrence of cerebrospinal fluid changes (CSF) in monosymptomatic optic neuritis patients have been thought to serve as a possible indicator of future development of multiple sclerosis. Such changes include mononuclear pleocytosis, increase in total protein and relative immunoglobin G (IgG) concentration, varying numbers of discrete IgG bonds in the gamma globulin fraction on agar gel electrophoresis and a possible abnormal dis-
tribution of kappa and lambda antigenic determinants in immunodiffusion and on immunoelectrophoresis. Twenty-five patients with acute monosymptomatic optic neuritis were studied for changes in the CSF as a possible indicator of future development of multiple sclerosis. After ocular and neurological examinations, the patients were subjected to cytological examinations, determinations