Lung tissue hydrolysates: studies of the optimum conditions for the spectrophotometric determination of hydroxyproline

Abstract

Two procedures developed earlier by the authors for the spectrophotometric determination of hydroxyproline have been tested on hydrolysates of dried formalin-fixed and ethanol-fixed lung tissues. The effects of dilution of the hydrolysates and of the presence of various amounts of sodium chloride have been studied, as well as several methods commonly used t o remove competing amino-acids or other interfering materials from hydrolysates before the spectrophotometric determination of amino-acids. Several amino-acids reported to cause interference in other spectrophotometric methods for hydroxyproline determination have a negligible effect in the procedures used in the present study.Lung tissue hydrolysis with varying concentrations of hydrochloric acid, sulphuric acid and sodium hydroxide, under various conditions, has been studied. No reduction in hydroxyproline yield was observed when the acid hydrolyses were prolonged for several days. A simple procedure is described, in which hydrolysis takes place overnight a t 105" C in a polypropylene tube enclosed by a glass tube fitted with a spring-loaded stopper; this procedure has given good results over a long period.

Suppression of experimental atherosclerosis by the Ca++-antagonist lanthanum. Possible role of calcium in atherogenesis.

“…The dry weight of the intimamedia of the aortas was comparable within each group ifexpressed per kilogram body weight. However, there was a highly significant increase (P < 0.01) in mean aortic weight from 34 Fig. 1 shows the outlines of representative aortic surface area involvement with lesions for each atherogenic group.…”

Betamethasone and the Rhesus Fetus: Effect on Lung Morphometry and Connective Tissue

“…The amount of collagen present was calculated from the hydroxyproline content of the soluble fraction. This was measured either from the peak of the amino acid analysis or by colorimetric determination (4). The amounts of elastin and collagen were calculated from the value computed from known aliquots and expressed in micrograms (pg) per milligram (mg) dry weight of lung.…”

Synthetic liposomes are protective from bleomycin-induced lung toxicity

“…To quantify collagen content, lung hydroxyproline was measured by a standard assay (6). Briefly, frozen lung L209 PROTECTIVE ROLE FOR LIPOSOMES IN BLEOMYCIN LUNG TOXICITY tissue was thawed in 1 ml of distilled water (dH2O), homogenized by use of a hand-held tissue homogenizer, and transferred to heatresistant glass tubes.…”