1026
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Wang ZL, Yu S, Sether LA, Haughton VM. Incidence of unfused ossicles in the lumbar facet joints: CT, MR, and cryomicrotomy study. J Comput Assist Tomogr 1989; 13:594-7. [PMID: 2745776 DOI: 10.1097/00004728-198907000-00007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The incidence of unfused ossicles in the lumbar spine, in radiographic studies, is 0.7-1.5%. With a sledge cryomicrotome, we sectioned 273 lumbar facet joints in 38 adult cadavers and correlated the anatomic appearance of the joints with CT and magnetic resonance (MR) images. Ossicles were present in 13% of the cadavers and 2.6% of the facet joints and were demonstrated effectively by MR. The incidence of ossicles, which can be confused with fractures, in the facet joints is higher than previously reported.
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1027
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Wang DW, Yu S, Wu TG. [An experimental study of excimer laser angioplasty in vitro]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 1989; 17:83-5, 126. [PMID: 2529110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Intratube thrombus and in vitro intraarterial thrombus and isolated normal pig aortic wall were radiated by excimer laser with wavelength of 308 nm and pulse width of 20 ns. The single pulse energy and the numbers of pulses were varied at the constant beam size and pulse frequency and the results were studied by micrometer measurement and histological examination. The results show: (1) excimer laser can effectively ablate thrombus. With constant total energy (at the range from 10 to 50 J), the depth of vaporized thrombus was nonlinearly proportional to the single pulse energy. But with constant single pulse energy (at the range from 10-100m J), the depth of vaporized thrombus was in linear proportion to the numbers of pulses; (2) if coaxial position of laser beam with blood vessel was maintained, thrombus can be effectively vaporized without arterial wall damage; (3) the incision produced by excimer laser has microscopically precise edges: there is no evidence of thermal injury and adjacent tissue is unaffected. Our conclusion is that excimer laser can be used safely and effectively in angioplasty. It may be mainly by photochemical effect that excimer laser ablates organic tissue.
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1028
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Yu S, Haughton VM, Sether LA, Ho KC, Wagner M. Criteria for classifying normal and degenerated lumbar intervertebral disks. Radiology 1989; 170:523-6. [PMID: 2911680 DOI: 10.1148/radiology.170.2.2911680] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The purpose of this study was to develop criteria for distinguishing normal and degenerated lumbar intervertebral disks. Cryomicrotome sections from and magnetic resonance images of 31 cadavers were reviewed. The immature nucleus pulposus, found up to age 2 years; the transitional nucleus pulposus, found in teenagers; and the adult nucleus pulposus were associated with an intact anulus fibrosus without tears except for small concentric or transverse tears in the periphery of the anulus fibrosus. Discoloration of the nucleus pulposus, diminishing disk height, and diminishing signal intensity were associated consistently with a radial tear of the anulus fibrosus. The severely degenerated nucleus pulposus was associated also with a radial tear or complete disruption of the anulus fibrosus. The results suggest that intervertebral disk normally progresses from the immature to the transitional to the adult nucleus pulposus. When a radial tear develops in the anulus there is shrinkage and disorganization of fibrocartilage in the nucleus pulposus and replacement of the disk by dense fibrous tissue and cystic spaces.
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1029
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Flye MW, Yu S. The inhibition of cell mediated cytotoxicity by 16,16 dimethyl PGE2. Transplant Proc 1989; 21:1156-7. [PMID: 2705217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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1030
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Daniels DL, Czervionke LF, Yu S, Ho PS, Pech P, Pojunas KW, Williams AL, Haughton VM. The effect of patient positioning on MR imaging of the internal auditory canal. Neuroradiology 1988; 30:395-8. [PMID: 3211315 DOI: 10.1007/bf00404104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Identification of individual cranial nerves and complete exclusion of tumor in the internal auditory canal may be difficult with MR, especially in imperfectly positioned patients. MR studies of the temporal bones in patients and in normal volunteers positioned non-rotated or canted were correlated with corresponding cryomicrotomic sections. Especially in axial images, oblique sectioning of cranial nerves VII and VIII may cause difficulty in identifying individual nerves. A combination of axial and coronal short TR and TE images can be used to confidently exclude intracanalicular tumor in most cases.
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1031
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Osterloh J, Yu S. Simultaneous ion-pair and partition liquid chromatography of acetaminophen, theophylline and salicylate with application to 500 toxicologic specimens. Clin Chim Acta 1988; 175:239-48. [PMID: 3416485 DOI: 10.1016/0009-8981(88)90100-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Acetaminophen (A), salicylate (S), and theophylline (T) are three common pharmaceutical agents involved in drug overdose for which determinations of serum drug concentrations play a pivotal role in clinical management. All three must be included in overdose screening, but often separate methods must be used. By combining reverse phase high performance liquid chromatography (HPLC) for A and T with ion-pair techniques for S, all three drugs can be chromatographed and quantitated simultaneously. A water-soluble ion-pair of S and 2-amino-2-(hydroxy-methyl)-1,3-propanediol eluted in a mobile phase of 4% acetonitrile and 12% acetic acid in water. Relative retention times for A, T and S were 0.41, 0.57 and 1.75 with an internal standard of 8-chlorotheophylline. Validation studies demonstrated recoveries of 88-104%, intraasay precisions of 2.1-6.6%, interassay precision of 3.8-8.0%, detection limits and linearity ranges of 2-200 mg/l for A and T and 10-1,000 for S. Seventy-two drugs were tested for interference. Accuracy studies showed no significant biases when compared to other methods. The method is convenient for toxicologic screening or therapeutic drug monitoring. In 576 consecutive serum specimens submitted for general toxicologic screening, 7.3% were positive for A, 5.2% for S, and 1.7% for T. Only 1.7% had critical concentrations indicating intoxication.
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1032
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Adelstein GW, Yen CH, Haack RA, Yu S, Gullikson G, Price DV, Anglin C, Decktor DL, Tsai H, Keith RH. Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase. J Med Chem 1988; 31:1215-20. [PMID: 2836591 DOI: 10.1021/jm00401a024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue. The potency showed a correlation to the calculated pKa of the aniline nitrogen atom. Substitutions on the aniline and benzimidazole rings did not further enhance potency. Di- and trisubstituted aniline derivatives were potent inhibitors of the enzyme system. The preferred combination of substituents were a methoxy group on the benzimidazole ring and a single alkyl group on the aniline ring. One such compound, 76, was an effective inhibitor of acid secretion in the dog and was selected for further pharmacological study.
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1033
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Yu S, Li L, Shimazaki K. Response of spinach and kidney bean plants to nitrogen dioxide. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 1988; 55:1-13. [PMID: 15092511 DOI: 10.1016/0269-7491(88)90155-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/1987] [Accepted: 03/18/1988] [Indexed: 05/08/2023]
Abstract
Different responses of spinach and kidney bean plants to various concentrations of NO(2) in the light and in the dark were shown. Spinach is more resistant than NO(2) than kidney bean. It is not only due to its greater tolerance to NO(2)(-) accumulated in leaves, but also to its stronger ability to metabolize NO(2)(-). The injury of spinach induced by the exposure to high concentration NO(2) in the light was not caused by the accumulation of NO(2)(-), but concerned the large amount of accumulated NH(3). The primary causes of NH(3) accumulation were that the activity of nitrite reductase was not affected by the fumigation on the one hand, and the activities of glutamine synthetase and glutamate synthase were inhibited on the other.
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1034
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Abstract
A model of ischemic hepatic failure in Sprague-Dawley rats (SD) with 100% mortality has been developed by one-hour occlusion of the right portal vein and hepatic artery followed by left 70% hepatectomy. The intrasplenic injection of 40 x 10(6) syngeneic adult or three-day neonatal single liver cell suspensions decreased the mortality from 100% to 50% and 36%, respectively. Mortality decreased with increasing time from the intrasplenic injection of neonatal liver cells to the time of acute hepatic ischemia. Mortality also decreased with increasing interval between hepatic ischemia and removal of the transplanted liver cells by splenectomy. Intrasplenic injection of graded doses of neonatal liver cells decreased mortality from 75% at a dose of 10 x 10(6) cells, to 36% at 160 x 10(6) cells. Treatment of neonatal liver cells with metabolic inhibitors did not significantly affect their ability to reverse acute hepatic ischemia.
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1035
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Daniels DL, Yu S, Pech P, Haughton VM. Computed tomography and magnetic resonance imaging of the orbital apex. Radiol Clin North Am 1987; 25:803-17. [PMID: 3299477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This article describes the CT and MR appearance of the orbital apex and masses in this region. The sectional anatomy by axial, coronal, and sagittal planes as well as the thin-layer technique used to accomplish this is detailed first. Then the application of these techniques to the presence of tumors is illustrated and discussed.
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1036
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Abstract
The three polypeptide chains of fibrinogen, A alpha, B beta and gamma chain, are synthesized on separate polysomes. Fully formed fibrinogen is a six chain, disulfide-linked, dimeric molecule with a molecular weight of 340kDa. Previous pulse-chase studies with L-35 S methionine using the human hepatocellular carcinoma cell line, Hep-G2, showed that the three chains are not immediately disulfide-linked and that there exist intermediate precursors as well as pools of A alpha and gamma chains (J. Biol. Chem. 259, 10574-10581, 1984). In this study the endogenous levels of fibrinogen and its precursors are measured by two different methods; pulse and steady-state labelling with L-35 S-methionine and immunoblotting. In Hep-G2 cells intracellular fibrinogen-related antigen is primarily (30-53%) composed of an A alpha-gamma complex and, to a smaller degree, of fully-formed fibrinogen (13-33%). Furthermore, the Hep G2 cell also contains endogenous pools of free gamma chain (11-26%). Other fibrinogen precursors (namely, the B beta-A alpha, B beta-gamma complexes as well as the fibrinogen half-molecule) do not appear to accumulate intracellularly. Most, if not all, of these precursors occur as isoforms but this heterogeneity is not due to varying degrees of glycosylation. In all the intracellular fibrinogen forms identified thus far, free sulfhydryl groups, detected by 14C-iodoacetamide incorporation, occur only in the A alpha-gamma complex and the free gamma chains.
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1037
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Flye MW, Yu S. The synergistic effect of superoxide dismutase and adenosine triphosphate-MgCl2 on acute hepatic ischemia. Transplant Proc 1987; 19:1324-6. [PMID: 3274324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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1038
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Chen Y, Li W, Yu S. Influence of passive smoking on admissions for respiratory illness in early childhood. BMJ : BRITISH MEDICAL JOURNAL 1986; 293:303-6. [PMID: 3089494 PMCID: PMC1340985 DOI: 10.1136/bmj.293.6542.303] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An association was sought between passive smoking and inpatient admissions for respiratory illness in 1058 children born between 1 June and 31 December 1981 and living in the neighborhoods of Nan-Jing Western Road and Yan-An Western Road in Jing-An District, Shanghai. The admission rate for first episodes of respiratory illness was positively correlated with the total daily cigarette consumption of family members during the children's first 18 months of life. The relative risk of developing a first episode of respiratory illness was 1.80 for children living in families including people who smoked 10 or more cigarettes a day compared with those living in non-smoking families. Multiple logistic regression analysis showed that the effect of passive smoking on inpatient admission for respiratory illness was independent of the child's birth weight, type of feeding, father's education, size of the home, and chronic respiratory disease among adults in the family. The adjusted odds ratios compared with the non-smoking group were 1.17 in families smoking 1.9 cigarettes daily and 1.89 in families smoking 10 or more cigarettes daily. These data suggest that exposure to household cigarette smoke of children in early life increases the risk of severe respiratory illness.
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1039
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Hsieh KP, Yu S, Wei YH, Chen CF, Wei RD. Inhibitory effect in vitro of PR toxin, a mycotoxin from Penicillium roqueforti, on the mitochondrial HCO-3-ATPase of the rat brain, heart and kidney. Toxicon 1986; 24:153-60. [PMID: 2939595 DOI: 10.1016/0041-0101(86)90117-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of PR toxin, a mycotoxin from Penicillium roqueforti, on the mitochondrial HCO3- -ATPase activity of the brain, heart and kidney from male Sprague-Dawley rats were determined by measuring colorimetrically the inorganic phosphate liberated by the ATPase in the presence or absence of bicarbonate ion. The IC50 (the concentration at which 50% of the enzyme activity is inhibited) of PR toxin on the mitochondrial HCO3- -ATPase from brain, heart and kidney were 12.7, 9.2 and 14.8 microM, respectively. The Michaelis-Menten constants (Km) of the enzyme from brain (1.1 mM), heart (1.5 mM) and kidney (2.3 mM) were not changed by PR toxin. Neither neutral nor anionic detergent increased the inhibitory potency of the toxin. It was concluded that of the three tissues tested, HCO3- -ATPase of the heart mitochondria was most sensitive to PR toxin, and that the toxin inhibited the HCO3- -ATPase in a non-competitive and irreversible manner.
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1040
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Su MQ, Yu S. Maternal diazepam exposure on brain ornithine decarboxylase and growth of offspring. PROCEEDINGS OF THE NATIONAL SCIENCE COUNCIL, REPUBLIC OF CHINA. PART B, LIFE SCIENCES 1986; 10:70-4. [PMID: 3714907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The prenatal treatment of diazepam on the developmental pattern of brain ornithine decarboxylase and the general growth of offspring were studied. Diazepam (120 mg/kg/day) was administered orally to pregnant Sprague-Dawley rats from day 14 to day 20 of gestation. The activity of brain ornithine decarboxylase and body weight of the offspring were measured from the late fetal stage to the early postnatal stage. It was found that diazepam inhibited both the prenatal and 4-hour postnatal ornithine decarboxylase activities, though the general maturation pattern of the enzyme in the brain was not much altered. It may indicate that diazepam inhibits early brain development. The enzyme activity fell off as it reached maturation. Prenatal treated neonates of 6-hour or older age group had the normal activities of brain ornithine decarboxylase. The general growth of the treated offspring was substantially retarded. Their body weights were very much lower than the control offspring. The results of the present study is an additional evidence that diazepam and other benzodiazepines should be used with great care in pregnant women.
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1041
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Yu S, Wang N, McKhann CF. The effect of immunity on pulmonary metastasis of a methylcholanthrene-induced fibrosarcoma and three of its clones. J Surg Oncol 1984; 27:51-8. [PMID: 6482454 DOI: 10.1002/jso.2930270113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A 3-Methylcholanthrene (MC)-induced fibrosarcoma and three of its clones were investigated for their metastatic potential in normal and tumor immune mice. The growth rates of the four tumors in vivo were similar. However, the mean survival times of the tumor-bearing mice were markedly different. Clone 10, the most immunogenic, showed very high metastatic potential and short survival, while clone 27, the least immunogenic, produced few metastases, resulting in much longer survival. Moderate numbers of metastases were produced by highly immunogenic 3-AM (parental tumor), and poorly immunogenic clone 34. Spleen cells from mice bearing highly immunogenic tumors lost their ability to neutralize tumors by day 28 after tumor inoculation, while those from mice bearing poorly immunogenic tumors remained cytotoxic, indicating that highly immunogenic tumors also induced immune suppression in the hosts. Immunization with specific tumors decreased the number of pulmonary metastases by 3 to 35-fold. Immunization with tumors that shared antigens provided protection against metastatic tumors as well as the local tumors. In contrast, immunization with antigenically different tumors gave no protection.
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1042
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Yu S, Sher B, Kudryk B, Redman CM. Fibrinogen precursors. Order of assembly of fibrinogen chains. J Biol Chem 1984; 259:10574-81. [PMID: 6088505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hep-G2 cells, incubated with L-[35S]methionine, incorporate radioactivity into fibrinogen and several fibrinogen-related compounds. Pulse-chase experiments indicate that several of these compounds are precursors of fibrinogen and that the cells contain intracellular pools of A alpha and gamma chains which participate in the assembly of fibrinogen. The rate of synthesis of the three component chains of fibrinogen is unequal with that of the B beta chain being less than that of the A alpha and gamma chains. The sequence of events which lead to the assembly of fibrinogen was deduced by determining the appearance of the radioactive chains in each of the fibrinogen precursors and in fibrinogen at various times during a pulse-chase incubation. Fibrinogen assembly commences while nascent incomplete B beta chains are attached at polysomes. Preformed A alpha and gamma chains, drawn from the intracellular pool, combine independently to the growing B beta chains. On completion of the nascent B beta chains, newly formed B beta-A alpha and B beta-gamma complexes are released from the polysomes and enter the luminal space of the endoplasmic reticulum. Later other A alpha and gamma chains are added by ordered disulfide interaction, leading to the eventual formation of dimeric fibrinogen.
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1043
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Yu S, Sher B, Kudryk B, Redman CM. Fibrinogen precursors. Order of assembly of fibrinogen chains. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)91001-x] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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1044
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Yu S. [Therapeutic results of ORS in infantile diarrheal dehydration]. TIANJIN YI YAO = TIANJIN MEDICAL JOURNAL 1984; 12:455-8. [PMID: 12313415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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1045
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Yu S, Sher B, Kudryk B, Redman CM. Intracellular assembly of human fibrinogen. J Biol Chem 1983; 258:13407-10. [PMID: 6315695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Hep-G2 cells, pulse-labeled with L-[35S]methionine, incorporate radioactivity within 2 min into precursor forms of fibrinogen and into fibrinogen. Pulse-labeled intracellular fibrinogen is first composed of radioactive B beta chains, followed by nascent A alpha chains. Radioactive gamma chains accumulate in the cells and later contribute, via intermediate forms, to the assembly of fibrinogen. Following a pulse-chase incubation with L-[35S]methionine, the radioactive composition of newly secreted fibrinogen also reflects the fact that there is a large intracellular pool of gamma chains.
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1046
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Abstract
A new radiobiological test system has been developed for lip epidermal/mucosal reactions in mice. This is intended for use in investigations of the effect of non-standard fractionation and of modifying drugs on oral radiation reactions in human cancer patients. An arbitrary scale of scores was devised, with separate scores for oedema of the lips and for erythema or exudation. After single doses of 13-20 Gy, the mouse lip epidermal reactions began at 5 days, reached a peak about 10-13 days, and had fallen to low values, but not to zero, by 21 days. Several different periods for averaging the reaction scores were tested for relative steepness and variability, the most useful being 10-12 days inclusive or the 12th day score alone. The use of longer periods of averaging led to apparent saturation of the scores. It was found that large doses of X-rays repeated at 21-23 day intervals did not lead to escalating waves of reactions unless each dose was greater than 17 Gy. With these larger doses, escalation of reactions occurred even if the intervals were extended.
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1047
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Yu S, Harding PG, Smith N, Possmayer F. Bovine pulmonary surfactant: chemical composition and physical properties. Lipids 1983; 18:522-9. [PMID: 6688646 DOI: 10.1007/bf02535391] [Citation(s) in RCA: 153] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Bovine pulmonary surfactant was obtained by endotracheal lavage of lungs from newly slaughtered cows followed by differential centrifugation. Lipid extracts of bovine surfactant contained 3% neutral lipid, mainly as cholesterol and diacylglycerol and 97% phospholipid. Phosphatidylcholine (79%) and phosphatidylglycerol (11%) accounted for most of the phospholipids with smaller amounts of phosphatidylethanolamine, phosphatidylinositol, lyso-bis-phosphatidic acid and sphingomyelin. Fatty acid analysis revealed high levels of palmitate in phosphatidylcholine and to a lesser extent phosphatidylglycerol, but not in the other diacylphospholipids. Phosphatidylcholine was 53% disaturated and phosphatidylglycerol was 23% disaturated. Monoenoic species accounted for the major proportion of the remaining lipid. The protein content was 10% as estimated by the Lowry procedure and 5% when determined by amino acid analysis. Extraction with chloroform/methanol removed ca. 90% of the protein but had no effect on the surfactant properties as evaluated by a pulsating bubble technique.
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1048
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Redman CM, Avellino G, Yu S. Secretion of proalbumin by canavanine-treated Hep-G2 cells. J Biol Chem 1983; 258:3446-52. [PMID: 6300044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The two processing sites in the conversion of preproalbumin to albumin are marked by arginine residues. Therefore, to study the mechanisms of albumin processing and secretion, the arginine residues of nascent albumin were replaced with canavanine by the incubation of Hep-G2 cells with this arginine analog. During a 4-h interval, canavanine inhibited (67%) the secretion of nascent albumin and increased the intracellular transit time of albumin secretion from 24 to 39 min. At 1 h, canavanine inhibited total protein synthesis by 19% and albumin synthesis by about 40%. Both the intracellular and secreted albumin produced by canavanine-treated cells were analyzed by DEAE-cellulose chromatography and were found to be more acidic than normal proalbumin and albumin. Further analysis on sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that the albumin produced and secreted by canavanine-treated cells appeared to have a larger molecular weight (by 4000) than serum albumin. The canavanine-treated cells were incubated with L-[3H]leucine and L-[3H]phenylalanine and the location of radioactive L-leucine and L-phenylalanine in the 30 NH2-terminal amino acid residues of secreted albumin was determined. The results indicated that canavanine-treated cells secreted proalbumin (79%) and also some fully processed albumin (21%). Preproalbumin was not secreted. Untreated Hep-G2 cells mostly secreted fully processed serum albumin (93%) with only traces of proalbumin (7%).
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1049
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1050
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Lannin DR, Yu S, McKhann CF. H-2 restriction of the T cell response to chemically induced tumors: evidence from F1 replaced by parent chimeras. THE JOURNAL OF IMMUNOLOGY 1982. [DOI: 10.4049/jimmunol.128.1.263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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