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Biomedical subjects

S Y Yu

Publications and source records attributed to S Y Yu.

At least 55 records · Page 3Linked to original sources
PubMed1990

Changes in vascular extracellular matrix accumulation reflect phenotypic differences between the arterial wall of pigeons resistant and susceptible to the development of spontaneous atherosclerosis.

White Carneau pigeons have previously been shown to be genetically susceptible to the development of spontaneous atherogenesis. The severity of development of atheromatous lesions is considerably greater than a more resistant breed of Show Racer pigeons. Analysis of levels of total hydroxyproline and isodesmosine in the thoracic aorta and celiac bifurcation of prelesion, six-week-old White Carneau and Show Racer pigeons, revealed an increased accumulation of total collagen and cross-linked elastin in the White Carneau arterial tissue. Using dot blot hybridization, measurements of steady state levels of several mRNAs in total RNA extracted from pigeon aortic tissue were also determined. While the increased deposition of extracellular matrix proteins was paralleled by a significantly greater recovery of mRNAs coding for pro alpha 1(1) collagen and elastin, in RNA extracted from White Carneau aortal tissue, increased recovery of mRNAs coding for an intracellular protein, gamma-actin were also observed in White Carneau aortal tissue. No differences in steady state levels of mRNAs coding for pro alpha 1(1) collagen and elastin were observed in RNA extracted from pigeon liver, suggesting a tissue specific increase in the mRNAs coding for these connective tissue proteins in aorta. A markedly reduced cell population however, was responsible for this overall increase in biosynthetic activity in White Carneau pigeon aortic tissue. This was demonstrated by a reduced cell count and by the recovery of reduced levels of total DNA in the thoracic aorta and celiac bifurcation of the White Carneau pigeon. The cell population in White Carneau aortic tissue exhibits therefore a markedly different phenotype with respect to a capacity for the biosynthesis of extracellular and intracellular proteins.

Actins↗
PubMed1990

[Diagnosis of pancreatic cancer with simultaneous detection of a pancreatic-cancer-associated antigen and pancreas-specific antigen].

We reported the purification and characterization of a pancreatic cancer-associated antigen from normal colonic mucosa (PCAAc) and pancreas-specific antigen (PaA) according to Kitada's and Loor's methods as well as the established method of double antibody enzyme-linked immunoassay for the detection of serum PaA and PCAAc; respectively. In our study, 155 serum samples were detected (including normal controls 40; pancreatic cancer 31; other malignant disease 56 and benign diseases 28). The results indicated that the overall sensitivity and specificity of a single PCAAc test for pancreatic cancer were calculated to be 70.98% and 96.43%; a single PaA to be 80.65% and 95.23%, respectively. Furthermore, the sensitivity and specificity of combined tests (PCAAc and/or PaA) for pancreatic cancer were calculated to be 96.77% and 90.91%. The diagnostic efficiency was 90.91%. None of 84 cases of nonpancreatic cancer and benign diseases has been found elevated PCAAc and PaA simultaneously. The results suggest that simultaneous detection of PCAAc and PaA would have increased the sensitivity of diagnosis for pancreatic cancer.

Antigens, Neoplasm↗
PubMed1989

Connective tissue, mechanical, and morphometric changes in the lungs of weanling rats fed a low protein diet.

We studied the effect of low-protein diet (8% casein) on lung growth in rats from 3 to 7 weeks of age. Their diet was isocaloric with that of control animals fed a diet of 20% casein. The calorie intake of experimental animals was increased during the first 3 weeks of the experiment, but they increased less (about 10%) in body weight, had less protein and less water when the whole body was examined, and had lower serum proteins and decreased urinary hydroxyproline. The experimental animals remained in positive nitrogen balance by maintaining low urinary nitrogen excretion. The lungs of the experimental animals were abnormal, with decreased absolute amounts of hydroxyproline and desmosine and of these relative to unit lung weight. The lungs contained more air per gram of lung tissue, and the volume of air in the lung was increased at all transpulmonary pressures above zero. When corrected for increased total lung capacity, there was a loss of recoil at mid-lung volumes. Saline-filled volume-pressure curves, corrected for lung volume, showed similar loss of recoil. Alveolar multiplication was quantitatively normal, but the experimental animals had larger alveoli. We conclude that the protein deprivation in isocalorically fed animals has a specific effect on lung scleroprotein content, which may be due to diminished synthesis, and this results in both structural and functional abnormalities in the lung. Our results indicate the importance of dietary protein in lung development and possibly as one of the causes of emphysema. Further studies are needed to know whether this would be a problem in infants of Kwashiokor.

Animals↗
PubMed1989

Serum ribonuclease and its isoenzymes for diagnosis of pancreatic cancer.

Serum ribonuclease (RNase) activity and its isoenzymes were determined by biochemical and PAGE electrophoretic separation technique in 20 patients with pancreatic cancer, in 27 with other gastroenterologic malignant tumors, 8 with acute pancreatitis, 7 with chronic pancreatitis, 5 with leukemia, 3 with chronic uremia of glomerulonephritis, and in 30 adult normal controls. Serum A1AT rocket immunoelectrophoresis and carcinoembryonic antigen (CEA) radioimmunoassay were also carried out simultaneously.

Adult↗
PubMed1989

Diagnostic value of plasma PABA level in pancreatic diseases.

NBT-PABA test was performed in 72 subjects with simultaneous determination of the plasma PABA time-concentration curve. The curve in 25 controls after oral administration of N-benzoyl-L-tyrosyl-P-aminobenzoic acid (NBT-PABA) peaked (3.88 +/- 0.78 micrograms/ml, M +/- SD) at the third hour. In patients with chronic pancreatitis (24) and pancreatic carcinoma (6), the curves were flattened, and peaked at the fifth hour (2.7 +/- 1.4 micrograms/ml, M +/- SD), and fourth hour (3.14 +/- 2.26 micrograms/ml, M +/- SD), respectively. The discrimination between the controls and patients with chronic pancreatitis was most significant in the third-hour plasma PABA concentration (P less than 0.0001). This study shows that determination of the third-hour plasma PABA concentration is better in sensitivity and specificity than the 6-hour urinary excretion of PABA, suggesting that the third-hour plasma PABA concentration after oral administration of NBT-PABA might be a sensitive index of exocrine pancreatic function test.

4-Aminobenzoic Acid↗
PubMed1989

[Study of factors affecting prognosis of cervical cancer using a microcomputer].

We set up a software system which can store, retrieve and handle the data for cervical cancer. The data of 526 patients with cervical cancer have been stored. The correlation between various prognostic factors and 5-year survival was studied by means of stepwise analysis. It was found that such factors as macroscopic type of tumor, hemoglobin, peritumoral lymphocytic infiltration and age of the patients influenced prognosis significantly. The best regression equation to predict the 5-year survival of patients was established by this method. It was proved that the calculated survival rate in correspondence with the real 5-year survival rate was 83.6%-99.55%. This study was important to us. We could then take appropriate therapeutic measures in the treatment of patients with cervical cancer.

Adult↗
PubMed1988

Acute myocardial infarction in elderly Chinese. A clinical analysis of 631 cases and comparison with 389 younger cases.

The purpose of this study was to define the clinical features of acute myocardial infarction in a group of elderly Chinese. The presenting symptoms, complications and mortality of acute myocardial infarction were compared in 631 patients (430 men and 201 women) aged 60 and over and 389 patients (333 men and 56 women) whose ages were under 60 years. The incidence of painless myocardial infarction was 17.6% in the elderly versus 5.9% in the younger group. Typical chest pain was present in 63.1% of the elderly and 84.3% of the younger Chinese. However, the incidence of other nonspecific presenting symptoms was higher in the elderly group. Likewise, the major complications in the elderly group were more severe than those in the younger group. For example, the incidences of cardiogenic shock, heart failure, arrhythmia, pulmonary infection and cardiac rupture in the older group were 19.8, 24.2, 77.2, 22.0 and 4.4%, versus 15.1, 19.5, 48.1, 9.5 and 1.1% in the younger group, respectively. The immediate (4 week) mortality rate of the older group was 21.9% (over 80 years 51.5%), but was only 11.0% in the younger group. Although the incidences of hypertension and pulmonary disease were significantly greater in the elderly group, these diseases alone did not account for the higher mortality rate in the elderly.

Adult↗
PubMed1987

Decreased elastic fibers and desmosine content in incompetent cervix.

Incompetence of the uterine cervix is a syndrome of painless, progressive dilatation and effacement occurring between the sixteenth and twenty-fourth weeks of gestation that represents abnormal functioning. It may serve as a model to elucidate normal function. Because the incompetent cervix results in painless opening of this organ without uterine contraction before term gestation, it is considered one of the causes of midtrimester spontaneous abortion, habitual spontaneous abortion, and early preterm labor. Untreated, it leads to rapid expulsion and often death of the fetus. We used light microscopy to compare decreased elastic fibers in incompetent cervices with those of normal nonpregnant and pregnant cervices. Morphologic analysis of this difference was extended to biochemical quantification of elastin content in one patient with cervical incompetence. The decrease in elastin suggests that one function of cervical elastin may be to maintain a closed and undilated cervix throughout gestation. There may be a relationship between changes in cross-linked elastin and the incompetent cervix; further studies are therefore indicated.

Amino Acids↗
PubMed1987

Reduction of chronic hypoxic pulmonary hypertension in the rat by an inhibitor of collagen production.

Chronic hypoxic pulmonary hypertension in the rat is associated with increased collagen and elastin in the pulmonary artery. We investigated whether excess vascular collagen contributes to chronic hypoxic pulmonary hypertension by administering the proline analogue cis-4-hydroxy-L-proline (cHyp), an agent relatively specific for inhibiting collagen production, to rats exposed to chronic hypoxia. Sprague-Dawley rats (weighting 200 g) were exposed to air or hypoxia (10% O2-90% N2) for 3 wk. Groups studied were: air-exposed injected with saline, air-exposed injected with cHyp, hypoxic injected with saline, and hypoxic injected with cHyp. At the end of 3 wk, we measured mean right ventricular pressure (RVP) of animals breathing room air and hydroxyproline and desmosine contents of the main pulmonary artery trunk. Hypoxia increased RVP from 13 +/- 1 to 27 +/- 1 mm Hg (p less than 0.05); cHyp partially prevented this increase since RVP was 17 +/- 1 mm Hg (p less than 0.05). There was no effect of cHyp on cardiac output. Hypoxia increased collagen from 0.9 +/- 0.1 to 2.0 +/- 0.3 mg/artery (p less than 0.05); cHyp completely prevented this increase since collagen was 1.0 +/- 0.2 mg/artery (p less than 0.05). Hypoxia increased elastin from 1.1 +/- 0.1 to 2.4 +/- 0.2 mg/artery (p less than 0.05); cHyp had no apparent effect since elastin was 2.1 +/- 0.1 mg/artery. Also, cHyp did not affect RVP or vascular collagen or elastin in air-breathing animals. The cHyp treatment prevented luminal narrowing and thickening of arteriolar walls by hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Damage and repair of lung connective tissue in rats exposed to toxic levels of oxygen.

We studied damage and repair of lung connective tissue in rats exposed to toxic amounts of oxygen by measuring lung content of collagen and elastin and the number of collagen fragments in lung lavage fluid after exposure to 98% O2 for 60 h. Lung collagen was decreased 17%, and collagen fragments in lavage fluid were increased 4- to 5-fold in O2-exposed rats compared with those in control rats. No biochemical evidence of elastin degradation was found. Mild emphysematous changes and a leftward shift of fluid-filled, pressure-volume curves were induced within 2 wk after recovery from exposure to O2. Administration of the lathyrogen beta-aminopropionitrile worsened the emphysematous lesion produced by hyperoxia, suggesting that replacement of connective tissue during repair limits the extent of emphysema. We conclude that lung collagen is degraded and an emphysematous lesion is produced by relatively short exposure to toxic amounts of oxygen.

Aging↗
PubMed1987

[Different effects of selenium on proliferation of human lung adenocarcinoma cells and human embryonic lung diploid cells in vitro].

After treating human lung adenocarcinoma cells by Na2SeO3 (1 microgram/ml) for 24 hours, its mitotic index decreased by 50%. The reduction rate was directly proportional to selenite concentration (1-5 micrograms/ml). In the meantime, the labelling index, growth rate and progression of the cell cycle were also inhibited. In contrast to the above observation, there was no marked change in the cell count, mitotic index, labelling index and the average silver granule number in the human embryonic lung diploid cells treated by Na2SeO3 (1-5 micrograms/ml) for 1-3 days. When human embryonic lung diploid cells were mix-cultured with human lung adenocarcinoma cells in the presence of 5 micrograms/ml Na2SeO3 for 24 hours, the former maintained a normal morphology, while the lung cancer cells showed heavily vacuolated cytoplasms and distorted nuclei.

Adenocarcinoma↗
PubMed1987

[Mechanism of the anticancer action of selenium--influence on glycolysis and its key enzyme].

The aerobic glycolysis rate and mitochondria-bound hexokinase activity of ascitic liver cancer cells are 8 and 50 times as high as those of the normal liver cells, and they can be inhibited by Na2SeO3 in concentration below 10 micrograms/ml. The inhibitory effect increases with selenium concentration. In contrast, Na2SeO3 at the same concentration does not significantly affect the glycolysis rate and mitochondria-bound hexokinase activity of the normal liver cells. The selective action of selenium on energy metabolism of the liver cancer cells may account for its inhibitory effect on cancer cells.

Animals↗
PubMed1986

[Mechanism of cell damage by hematoporphyrin derivatives (HPD) plus light--I. Photooxidation of hepatoma cell membrane by HPD plus light].

Ascitic hepatoma cells of mice were incubated with three HPD. After the cell-bound HPD was treated by visible light, the product of membrane lipid peroxidation--malondialdehyde (MDA) was determined. The results showed that the MDA level increased with HPD concentration and exposure time, but it was unchanged in the control. Beta-carotene, a quencher of singlet oxygen, could inhibit the lipid photooxidation of the membrane of cell-bound HPD resulting in a decrease of MDA level which decreased with increase of beta-carotene concentration. Adding vitamin E in vitro and vivo, formation of the product of membrane lipid peroxidation of cell-bound HPD by light was inhibited and the MDA level decreased with the increase of vitamin E concentration. These results show that the singlet oxygen, produced by HPD bound cells following light activation, reacts directly with the polyunsaturated fatty acids on cell membrane to produce lipid peroxides leading to cellular damage.

Animals↗