PubMed · 14926932
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A B DROOGLEEVER FORTUYN. 1952-01-10. [Lenz's method].. https://pubmed.ncbi.nlm.nih.gov/14926932/
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The study of relations between structural organization and functions of microcirculatory networks is a major aim of modern microangiology. Such a structural aspect of microvessels (MVs) as their spatial arrangement has substantial influence on their transport and other functional properties. This paper describes a methodology of spatial correlation analysis for isotropic blood and lymphatic MVs which is based on a stereological estimator of the pair correlation function [g3D(r)] created recently by the authors for systems of elongated objects. The following main features of the methodology are presented: (i) interpretation of the shape of g3D(r) curves, (ii) their quantitative description by numerical parameters, and (iii) limitations of the method arising from statistical requirements to MVs under investigation. The methodology is considered in the light of multilevel sampling designs, which are typical for biomedical morphology. The estimator with its methodological framework is applied to perifollicular blood capillaries in the adult rat thyroid. Related methods for studying the spatial arrangement of MVs are thoroughly discussed in the paper.
Albino animals display a hypopigmented phenotype associated with several visual abnormalities, including rod photoreceptor cell deficits, abnormal patterns of connections between the eye and the brain and a general underdevelopment of central retina. Oculocutaneous albinism type I, a common form of albinism, is caused by mutations in the tyrosinase gene. In mice, the albino phenotype can be corrected by functional tyrosinase transgenes. Tyrosinase transgenic animals not only show normal pigmentation but the correction of all visual abnormalities associated with albinism, confirming a role of tyrosinase, a key enzyme in melanin biosynthesis, in normal retinal development. Here, we will discuss recent work carried out with new tyrosinase transgenic mouse models, to further analyse the role of tyrosinase in retinal development. We will first report a transgenic model with inducible tyrosinase expression that has been used to address the regulated activation of this gene and its associated effects on the development of the visual system. Second, we will comment on an interesting yeast artificial chromosome (YAC)-tyrosinase transgene, lacking important regulatory elements, that has highlighted the significance of local interactions between the retinal pigment epithelium (RPE) and developing neural retina.
BACKGROUND: A complicated malformation of the fundus accompanied by typical ocular coloboma was detected in albino fatty liver Shionogi (FLS) mice. We elucidated a new type of 3-dimensional anomalous structure inside the eye in this mouse strain. METHODS: The fundi of FLS mice aged 1, 3, 5, and 20 weeks were observed intensively, both macroscopically and by light microscopy. For the prenatal study, coronal serial sections of eyes of FLS embryos were examined by light microscopy on gestation day (GD) 15.0. RESULTS: The frequency of ocular coloboma was almost 70% in FLS mice, and the inheritance mode of this anomaly is suggested to be autosomal recessive with incomplete penetrance. Stereoscopic observation and light microscopy revealed that the mice had characteristic fundus features at any age during the postnatal period. Following ectopic ciliary epithelia, the surface of the retina protruded like a roof, and on the opposite side of the "roof," a translucent membrane without retinal tissue and choroidal tissue was also consistently detected in the inferior part of the fundus. On GD 15.0, the inner layer and the outer layer were not normally fused at the optic fissure, where a part of the outer layer was absent and the irregular fold of the inner layer was conspicuous in the colobomatous eye of the FLS embryo. CONCLUSIONS: The characteristics of the ocular coloboma in FLS mice are thought to be similar to a mild-type malformation in humans. These ocular defects seem to be situated along the failed fetal optic fissure.