Scanning Electron Microscopy (SEM) was used to study vascular casts of twenty-four autopsy eyes taken from patients with long-standing insulin-dependent Diabetes Mellitus. These casts were compared to casts of ten 'normal' autopsy eyes from patients without a history of diabetes or other vascular disease. The SEM findings in the choroidal vessels of the diabetic eyes included: increased tortuosity, focal vascular dilations and narrowings, hypercellularity, vascular loops and microaneurysm formation, 'drop-out' of choriocapillaries, and sinus-like structure formation between choroidal lobules in the equatorial area. In the iris, neovascularization was evident in the vascular casts in cases with clinically recognized rubeosis iridis. These findings indicate that there is significant involvement of the uveal tract in diabetic eyes. The present study strongly supports the Hidayat and Fine light microscopic observation that the diabetic choroid demonstrates significant vascular changes (e.g. narrowed vessels with possible 'drop-out' of capillaries and neovascularization). Changes in the diabetic choroid, especially in the choriocapillaris, may be a contributing factor in diabetic retinopathy, resulting in decreased oxygenation of the outer layer of the retina. Short reviews and updated information of diabetic eye disease provide some additional insights into the vascular problems in the eye.
Vascular casts (Batson mixture) of ocular angioarchitecture were prepared from ten human orbits removed at autopsy. The age of donor specimens ranged from seven months to 68 years. The time interval between death and injection of the orbits averaged seven hours with a range of five hours. The resulting vascular casts were examined using light microscopy and scanning electron microscopy (SEM). We present photomicrographs of our vascular casts that demonstrate predictable variations of the human choriocapillaris angioarchitecture according to the region of the choriocapillaris under examination (i.e. posterior pole, equatorial, peripheral, peripapillary, or submacular areas). Our discussion represents an effort to help clarify some persistent controversies concerning the human choroidal angioarchitecture.
The nucleus of the pontobulbar body (PBu) in the North American opossum is located, for the most part, adjacent to the motor root of the trigeminal nerve. Material prepared by degeneration and autoradiographic methods shows that the PBu receives projections from the facial motor-sensory cortex, red nucleus, spinal cord and cerebellum. The latter fibers probably take origin within the fastigial nucleus. Each of the afferent connections ends in a restricuted part of the PBu, but there is considerable overlap. Use of the horseradish peroxidase technique reveals that the PBu projects to the spinal cerebellum (anterior lobe, pyramis and paramedian lobules), to visual-auditory areas of the vermis and to the lobus simplex as well as to crus I and II of the hemispheres. Although there is some topography to such projections, it is not sharply defined and many regions of the PBu contain labelled neurons after injections of horseradish peroxidase into widely separate areas of the cerebellar cortex. Because of its embryogenesis and position, the PBu is often considered part of the dorsolateral basilar pons. It appears from our material, however, that the organization of PBu afferent and efferent connections is different from that of the adjacent basilar pons, and arguments for considering the PBu a separate precerebellar nucleus are presented.
Vascular casts (Batson mixture) of ocular angioarchitecture were prepared from ten human orbits removed at autopsy. The age of donor specimens ranged from seven months to 68 years. The time interval between death and injection of the orbits averaged seven hours with a range of five hours. The resulting vascular casts were examined using light microscopy and scanning electron microscopy (SEM). We present photomicrographs of our vascular casts that demonstrate predictable variations of the human choriocapillaris angioarchitecture according to the region of the choriocapillaris under examination (i.e. posterior pole, equatorial, peripheral, peripapillary, or submacular areas). Our discussion represents an effort to help clarify some persistent controversies concerning the human choroidal angioarchitecture.
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