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S Y Yu

Publications and source records attributed to S Y Yu.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effect of proline analogs on oxygen toxicity-induced pulmonary fibrosis in the rat.

Proline analogs inhibit collagen biosynthesis and prevent accumulation of collagen in tissues. The antifibrotic effects of three proline analogs, cis-hydroxyproline, L-azetidine-2-carboxylic acid, and L-3,4-dehydroproline, were compared in a rat oxygen toxicity model. The specificity of these agents for collagen was examined by measuring their effects on noncollagen protein and elastin accumulation in the lung. Increased lung collagen was produced by exposing rats to 95% O2 for 60 hr followed by a 2-week recovery period. Animals were treated with the proline analogs for the 2-week period. Oxygen exposure in untreated animals increased lung collagen 26% above air-breathing controls, and this increase was prevented by all three analogs. Increased noncollagen protein was also prevented by these agents, suggesting they were not entirely specific for collagen. Elastin accumulation, however, was not inhibited by cis-hydroxyproline. It was concluded that proline analogs were antifibrotic, but affected the metabolism of noncollagen protein.

Animals↗
PubMed1984

Elevation of histidinoalanine in calcified human aortas.

The cross-links histidinoalanine (HA); pyridinoline (Pyr); desmosine (Des); and isodesmosine (Ides) in human atherosclerotic aortas were studied. Only HA showed a significant increase in calcified aortas, with a high concentration in the insoluble "mineralized" fraction, which was separated out after treatment of tissues with pronase E. The cross-links composition was similar among "mineralized" fractions prepared from tissues of varying degrees of calcification: values were 2.40; 0.10; 0.17; and 0.16 moles per 1000 moles of amino acid residues for HA; Pyr; Des; and Ides, respectively. The findings suggest that the HA-containing peptide may play an important role in the calcification process of aortic tissues.

Amino Acids↗
PubMed1983

Evaluation of the urinary desmosine radioimmunoassay as a monitor of lung injury after endobronchial elastase instillation in sheep.

Thirty male sheep were treated with varying doses of endobronchial elastase. Urinary excretion of elastin peptides was then measured by desmosine radioimmunoassay and compared with pre-enzyme values. Mean linear intercepts were measured in treated and untreated lobes 4 wk later, and in addition, lung perfusion, ventilation, and volume were measured before enzyme treatment and 4 wk later using radionuclide-imaging techniques. Most of the elevation in urinary desmosine excretion occurred in the first 48 h after elastase administration. The increase in desmosine excretion was positively correlated with: enzyme dose (r = 0.74, p less than 0.01), increase in mean linear intercept (r = 0.61, p less than 0.05), decrease in lung perfusion (r = 0.77, p less than 0.01), and decrease in ventilation (r = 0.58, p less than 0.05). These results demonstrate that the urinary desmosine radioimmunoassay is a reliable index of pulmonary elastin breakdown and of several resultant anatomic and physiologic stigmata of pulmonary emphysema.

Amino Acids↗
PubMed1983

Peplomycin sulfate and pulmonary fibrosis: hydroxyproline, uronic acid, proline hydroxylase and glucosamine 6-phosphate synthetase in lungs of hamsters treated with peplomycin.

Effect of peplomycin sulfate (PLM) on pulmonary fibrosis was examined. Hydroxyproline, uronic acid, proline hydroxylase (EC 1.14.11.2) and glucosamine 6-phosphate synthetase (EC 2.6.1.16) in lungs of hamsters treated with PLM were studied and compared with those of hamsters treated with bleomycin (BLM). PLM, when administered intraperitoneally, one injection daily for 10 consecutive days, at either a high- (5 mg/kg) or low- (2.8 mg/kg) dosage-level, caused no significant increase of lung hydroxyproline and uronic acid as compared with controls. BLM on the other hand effected a significant increase in lung hydroxyproline on the high-dosage level (5 mg/kg) but not on the low-dosage level (2.8 mg/kg). In contrast, when administering PLM intratracheally, the concentrations of hydroxyproline in lungs increased 20% over the control levels. A transient increase of proline hydroxylase and glucosamine 6-phosphate synthetase also occurred shortly after the instillation. These increases were also observed in the corresponding groups treated with BLM, which confirmed the previous observations by other investigators. However, the magnitude of the increase was relatively lower in those values of PLM as compared with those of BLM. These data suggested that (1) PLM, when administered with multiple dosages intraperitoneally, showed no significant effect on the elevation of lung hydroxyproline; (2) PLM, when administered with a dose intratracheally, induced pulmonary fibrosis similar to that caused by BLM. However, the hydroxyproline accumulation in lungs of PLM-treated hamsters was less than in those of the BLM-treated; (3) The fibrotic effect on the lungs caused by either PLM or BLM was probably attributed to acceleration of the syntheses of collagen and acidic glycosaminoglycans.

Animals↗
PubMed1982

Factors regulating lamellar body volume density of type II pneumocytes in excised dog lungs.

Pulmonary arterial occlusion (PAO) produces multiple alterations in the physiological/biochemical environment of lung cells as well as dysfunction of the lung's surfactant system, which is considered to play a significant role in mediating lung injury. The present studies were performed using 66 excised dog lungs to evaluate the impact of alterations in ventilation, substrate availability, alveolar CO2 tension, hydrogen ion and bicarbonate concentrations, and temperature and neural denervation on the lamellar body (LB) volume density of type II pneumocytes. Ventilating excised nonperfused dog lungs with room air (0% CO2) for 4 h at 38 degrees C resulted in severe reductions (68-77%) in LB volume density. Supplementing inspired gas with 5% CO2 prevented LB depletion, while ventilation with 2.5% CO2 moderated the severity of depletion to 17-27% of control. Ventilation with 10% CO2 tended to increase LB volume density by increasing the number of LBs per cell, whereas reductions in LB volume density predominantly resulted from a decrease in LB size. The level of ventilation had no significant effect on LB volume density independent of inspired CO2 concentration. Reducing temperature to 5 degrees C prevented LB depletion. Lung perfusion with autologous whole blood failed to moderate the severity of LB depletion during room air ventilation despite the increased availability of metabolic substrates for cellular metabolism. Adding hydrochloric acid to maintain physiologically normal hydrogen ion concentrations in the perfusing blood had a small effect in ameliorating the severity of LB depletion. These results indicate that alveolar CO2 tension and bicarbonate concentration are major factors regulating the LB content of type II pneumocytes and suggest an important link between the gas exchange and phospholipid metabolic functions of the lung.

Animals↗
PubMed1981

Urinary excretion of desmosine in patients with severe burns.

Urinary excretion of total desmosine was measured by a radioimmunoassay in severely burned adult males, as well as in normal adult males. Total urinary desmosine was significantly elevated in all the samples in the burned patients, who had injuries involving more than 19% of total body surface area. The values of 24-hr urinary desmosine for the burned patients ranged from 250--1,411 nmoles, as compared with 82--142 nmoles for normal controls. These were equivalent to 14--78 mg of elastin degraded for the burned patients and 5--8 mg for normal controls. Urinary desmosine values expressed as nmoles per g of creatinine were also higher than the corresponding normal values, ranging from 110--768 nmoles versus 63 +/- 6 nmoles for normal controls. Urinary excretion of total hydroxyproline in the burned patients was also higher than in normal controls, ranging from 56--471 mg per 24 hrs, or 36 to 413 mg per g of creatinine, vs. 31 +/- 6 mg per 24 hr, or 23 +/- 2 mg per g of creatinine, in burned patients and normal controls, respectively. These values of hydroxyproline were equivalent to 413--3,623 mg of collagen and 238 mg of collagen, respectively. In the burned patients, both urinary desmosine and hydroxyproline values were elevated from day 1 post-burn, and reached peak levels in days 2--12, declining thereafter but remaining higher than values for normal controls through day 60. The metabolism of elastin and collagen in skin of burned patients was probably highly accelerated for a long time, at least through day 60 post-burn.

Adult↗