Biomedical subjects

X X Luo

Publications and source records attributed to X X Luo.

21 records · Page 2Linked to original sources

PubMed1989

Age-related changes in the extracellular matrix of the human optic nerve head.

By using immunofluorescent staining we were able to characterize the age-related changes in the macromolecules making up the extracellular matrix of the lamina cribrosa of the human optic nerve head. As the cores of the cribriform plates enlarged with age, there were age-related increases in the apparent density of collagen types I and III and elastin that constituted the connective tissue support of the nerve bundles. Collagen type IV coated the cribriform plates as basement membranes and was also present within the cores as a fine filamentous network, which increased in density with age as the cribriform plates expanded. As this tissue ages, individual differences leading to more or less of a particular macromolecule of the extracellular matrix may alter the support function of the lamina cribrosa and influence the degeneration of the optic nerve associated with glaucoma.

Aging↗

PubMed1989

[Effects of ranitidine and cimetidine on ventricular fibrillation threshold and dispersion of refractory period in early myocardial ischemia].

The effects of two H2-receptor antagonists, ranitidine (Ran) and cimetidine (Cim), on the ventricular fibrillation threshold (VFT) and dispersion of the refractory period in animals with early acute myocardial ischemia induced by coronary artery ligation (CAL) were studied. The measurement of VFT was obtained in anaesthetized rats. The control group showed a decrease in VFT from 6.7 +/- 0.4 to 3.1 +/- 0.7 V 5 min after CAL, while Ran (15 mg/kg iv) and Cim (40 mg/kg iv) increased VFT from 2.8 +/- 0.7 to 5.4 +/- 1.7 V and from 3.1 +/- 0.8 to 8.1 +/- 2.7 V, respectively. By means of suction electrodes, FRP in different ischemic zones were recorded in anaesthetized rabbits, and differences between FRP in different zones were taken as the dispersion of FRP. After CAL, the control group exhibited a prolongation of FRP in central ischemic zone and a shortening of FRP in boundary zone, i.e., a dispersion of FRP was increased. Both Ran (5 mg/kg iv) and Cim (25 mg/kg iv) markedly decreased the extent of dispersion of FRP. It is concluded that the anti-arrhythmic effects of Ran and Cim may be attributable to increases in VFT and decreases in dispersion of FRP.

Animals↗

PubMed1987

Extracellular matrix of the human lamina cribrosa.

We used immunoperoxidase staining and double immunofluorescent staining to demonstrate the macromolecular components of the extracellular matrix of the lamina cribrosa from young human donors. The cribriform plates were made up of a core of elastin fibers with a sparse, patchy distribution of collagen type III. The plates were coated with collagen type IV and laminin; these basement membrane components were presumably made by the astrocytes that were distributed on the surfaces of the plates. The insertion of the lamina cribrosa in the sclera was made up of concentric, circumferential elastin fibers that surrounded the lamina cribrosa and were continuous with the elastin in the cribriform plates. Astrocytic processes extended into the bundles of elastin fibers, whereas the basement membrane components extended into the sclera. The mechanical properties of the macromolecules of the extracellular matrix of the lamina cribrosa may make this tissue compliant and sensitive to intraocular pressure. Perhaps individual differences in the macromolecular components of this tissue contribute to the glaucomatous changes in the optic nerve head.

Adolescent↗