Proteoglycans in Bruch's membrane.
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Biomedical subjects
L C Pino
Publications and source records attributed to L C Pino.
Permeability of the neonatal rat choriocapillaris to hemeproteins and ferritin.
The permeability of the endothelium of the capillaries of the rat choriocapillaris to circulating macromolecules was examined during the first post-natal week of development using hemeproteins of different molecular dimensions and ferritin. At this stage of development capillaries and photoreceptor cells in the neural retina are not fully formed, but the choriocapillaris has an adult-like morphology. Thus, through these differences in neural and vascular architectures the possible functional relationships between the retina and choriocapillaris can be explored. High levels of horseradish peroxidase [Einstein-Stokes radius (ESR) 3 nm] activity were localized in Bruch's membrane within 2 minutes after intravenous tracer injection. In contrast, scant levels of hemoglobin (ESR, 3.2 nm) and no catalase (ESR, 5.2 nm) activity were observed here at 75 and 90 minutes, respectively. Only a few ferritin particles (ESR, 6.1 nm) crossed the choriocapillary endothelium after a 90-minute circulation. The results demonstrate that in the neonatal rat the choriocapillaris has the same restrictive properties as have been described for the adult eye (Pino and Essner, 1980, 1981), even in the absence of retinal capillaries and functional photoreceptor cells.
Animals↗
Location and chemical composition of anionic sites in Bruch's membrane of the rat.
The location and chemical composition of anionic sites in Bruch's membrane (BM) were examined using cationic probe molecules demonstrable in electron microscopic preparations and tissue digestion with specific degradative enzymes. Ruthenium red and native lysozyme revealed densities distributed at regular intervals in two major components of BM: the basal laminae of the retinal pigment epithelium (RPE) and choriocapillary endothelium (EN). Staining was not observed with succinylated lysozyme (anionic). Colloidal iron also failed to stain BM components. Following crude heparinase treatment at 43 degrees C (specific for heparan sulfate) anionic sites in the RPE basal lamina were not demonstrable with either ruthenium red or native lysozyme. Sites in the EN basal lamina were not affected. Chondroitinase treatment removed almost all of the ruthenium red-positive material in the EN basal lamina; lysozyme binding here was markedly reduced. No changes were observed in the RPE basal lamina after chondroitinase digestion. There was no morphological evidence for site removal by either neuraminidase or leech hyaluronidase, although a detachment of the RPE from BM often occurred after incubation of eye tissue in the latter. Pronase E removed all stainable material. These findings indicate that anionic sites in BM consist to a large extent of chondroitin sulfates and heparan sulfate.
Animals↗
The relationships between the Golgi apparatus, GERL, and lysosomes of fetal rat liver Kupffer cells examined by ultrastructural phosphatase cytochemistry.
Kupffer cells are the sinusoidal macrophages of the liver. Using ultrastructural phosphatase cytochemical methods, we examined the relationship between the Golgi apparatus, GERL, and lysosomes of Kupffer cells in fetal rat livers identified, in part, by their ability to phagocytize intravenously injected latex spheres. Thiamine pyrophosphatase (TPPase) activity was localized to the inner Golgi saccules and some vesicles in the Golgi region but not to GERL. A TPPase-like activity, demonstrable in lysosomes, was abolished by sodium fluoride but not suppressed by the alkaline phosphatase inhibitors L-cysteine and L-p-bromotetramisole. Acid phosphatase (AcPase) was localized by GERL, some coated vesicles, and in lysosomes, but not to the Golgi stacks. Continuities between GERL and lysosomes were observed. Phagosomes containing internalized latex spheres received TPPase and AcPase sequentially. TPPase was localized in phagosomes immediately after latex administration. AcPase activity was not found here until at least 10 minutes following the injection of the particulates. Our findings indicate that Kupffer cell lysosomes are derived from GERL, but also suggest that phagosomes may receive material packaged by the Golgi apparatus as well as GERL.
Acid Phosphatase↗