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Biomedical subjects

Y Yu

Publications and source records attributed to Y Yu.

At least 415 records · Page 23Linked to original sources
PubMed1997

[Sphygmographic parameters in fighter and transport pilots].

To evaluate and discover hidden cardiovascular trouble in pilots, the cardiovascular function of 129 active male pilots was examined with a new sphygmographic method. 13 pilots (10.3%) were found to have abnormal cardiovascular function. The average arterial blood pressure and medium artery modulus of the fighter pilots aged from 30 to 34 years are inferior to those aged from 25 to 29 obviously, however, that is not the case in transport pilots. This indicates that frequent examination of cardiovascular function with convenient special method is necessary for the improvement of the quality of medical monitor on pilots.

Adult↗
PubMed1997

[Dynamic analysis of 24 h blood pressure in pilots and hypertensive patients].

Blood pressure of 63 healthy male pilots and 20 primary hypertensive patients was measured with the "Smart LINK Ambulatory Monitoring System". The BP readings were taken every 30 min in daytime and 60 min at night for 24 h. The results showed that two peaks appeared at 7:00-9:00 A.M. and 16:00-19:00 P.M. and two valleys at 12:00-14:00 P.M. and 24:00-5:00 A.M. in healthy pilots, but the hypertensive subjects showed higher systolic or/and diastolic blood pressure continuously.

Aerospace Medicine↗
PubMed1997

[The changes and relation among platelet function, plasma heparin and anti-coagulation-III: activity in patients with hemorrhagic fever with renal syndrome].

Blood platelet count (BPC), platelet adhesive rate (PAdT), platelet aggregate rate (PAgT), plasma heparin and anti-coagulation-III: activity (AT-III: alpha) were determined in 55 cases with hemorrhagic fever with renal syndrome (HFRS). In these patients, decreased BPC, defect PAdT, PAgT, increased plasma heparin as well as decreased AT-III: a were found, moreover, these changes were much notable in patients with severe type. A positive correlation existed between plasma heparin and BPC, PAdT, PAgT in cases with 80% AT-III: alpha or above (r values were -0.4344, -.7157 and -0.5547 respectly, p<0.01). The results suggested that plasma heparin may be one of factors resulting in decreased BPC and defect platelet function in HFRS patients with 80% AT-III: alpha or above.

Adolescent↗
PubMed1997

[Preparation and evaluation of a strong polar polymer capillary column].

A strong polar organic polymer porous layer open tubular capillary column, named OPPLOT-A column, was prepared by in situ copolymerization with the strong polar acrylonitrile as monomer and divinylbenzene as cross-linking agent. The polarity of the column is higher than that of the OPPLOT-Q, OPPLOT-R andd OPPLOT-S columns which prepared previously. The performance of the OPPLOT-A column was evaluated. It is effective to analyze alcohols, aldehydes, ketones, esters, ethers and nitriles etc., and especially for good separation of nitriles and aldehydes. The retention of the column is not influenced by water. The thermal stability of the OPPLOT-A column (200 degrees C) is lower than that of OPPLOT-Q (250 degrees C), -R (250 degrees C) and-S (210 degrees C).

English Abstract↗
PubMed1997

[Fine physical mapping of yeast chromosome V].

Electrophoretic karyotype of yeast strain A364a was obtained by pulsed field gel electrophoresis and the position of chromosome V on such karyotype was determined by means of dot hybridization with chromosome V-specific probe URA3. By cloning partially digested BamHI fragments of this chromosome DNA into integrative vector Yip5, a gene library specific to this chromosome was constructed. The number of the recombinants was much more than theoretically required. After screening probe-homologous fragments from this library and analysing such fragments with restriction enzymes BamHI, EcoRI, HindIII, PstI, and SalI, a fine physical map covering about 9.4% of A364a chromosome V (which was estimated as 620kb) was constructed. Further colony hybridization with boundary clones will enable us to "walk" throughout the whole chromosome.

Chromosome Mapping↗
PubMed1997

Lack of uncoupling of S phase and mitosis after irradiation in p53- human lymphoblast cell lines.

It has been shown that p53- human colorectal cancer cells arrest after DNA damage in a G2-like state and may then undergo DNA synthesis without intervening mitosis (Waldman et al., Nature 381, 713-716, 1996). To further clarify the role of p53 in the regulation of the G2/M-phase checkpoint, we have studied cells of three closely related human lymphoblastoid cell lines (TK6, WTK1 and TK6E6, an HPV16 E6-transfected TK6 line) with differing p53 status. The cells were irradiated with 1.5-12 Gy gamma rays with or without 2 mM caffeine. There was no evidence of uncoupling of DNA synthesis and mitosis after irradiation in the p53- cell lines, WTK1 and TK6E6, suggesting that this uncoupling may not be a universal phenomenon. The apparent formation of tetraploid cells after irradiation of cells of the p53- WTK1 line was due to the occurrence of a G2-phase block in a pre-existing tetraploid population. These results support the conclusion that control of the G2/M-phase checkpoint after irradiation may differ among different cell types.

Caffeine↗
PubMed1997

Rapid isolation of muscle and heart mitochondria, the lability of oxidative phosphorylation and attempts to stabilize the process in vitro by taurine, carnitine and other compounds.

We modified the isolation procedure of muscle and heart mitochondria. In human muscle, this resulted in a 3.4 fold higher yield of better coupled mitochondria in half the isolation time. In a preparation from rat muscle we studied factors that affected the stability of oxidative phosphorylation (oxphos) and found that it decreased by shaking the preparation on a Vortex machine, by exposure to light and by an increase in storage temperature. The decay was found to be different for each substrate tested. The oxidation of ascorbate was most stable and less sensitive to the treatments. When mitochondria were stored in the dark and the cold, the decrease in oxidative phosphorylation followed first order kinetics. In individual preparations of muscle and heart mitochondria, protection of oxidative phosphorylation was found by adding candidate stabilizers, such as desferrioxamine, lazaroids, taurine, carnitine, phosphocreatine, N-acetylcysteine. Trolox-C and ruthenium red, implying a role for reactive oxygen species and calcium-ions in the in vitro damage at low temperature to oxidative phosphorylation. In heart mitochondria oxphos with pyruvate and palmitoylcarnitine was most labile followed by glutamate, succinate and ascorbate. We studied the effect of taurine, hypotaurine, carnitine, and desferrioxamine on the decay of oxphos with these substrates. 1 mM taurine (n = 6) caused a significant protection of oxphos with pyruvate, glutamate and palmitoylcarnitine, but not with the other substrates. 5 mM L-carnitine (n = 6), 1 mM hypotaurine (n = 3) and 0.1 mM desferrioxamine (n = 3) did not protect oxphos with any of the substrates at a significant level. These experiments were undertaken in the hope that the in vitro stabilizers can be used in future treatment of patients with defects in oxidative phosphorylation.

Animals↗
PubMed1997

The prognosis of biopsy-proven lupus nephritis in chinese patients: long term follow-up of 86 cases.

OBJECTIVE: To investigate the prognosis of lupus nephritis (LN) and its influencing factors in patients with lupus nephritis in China. METHODS: A retrospective study was carried out in 86 patients followed up for at least 5 years. Clinical features, serological and immunological tests were investigated. Renal biopsies were performed at the beginning of the study and repeated in some cases during the follow-up period. All the 86 patients had serum creatinine (Scr) level less than 132.6 mumol/L at the initial presentation and were divided into three groups according to the level of Scr at the end of the study. Group I: the patients with normal renal function (Scr < 132.6 mumol/L); Group II: the patients with mild-moderate renal insufficiency (132.6 mumol/L < or = SCR < or = 530.4 mumol/L); Group III: the patients with end stage renal failure (ESRF) (Scr > or = 530.4 mumol/L). RESULTS: Forty-seven patients reached clinical remission with normal renal function, 11 had with stabilization of renal function, although the systemic lupus erythematosis (SLE) activity relapsed repeatedly, while 28 subjects developed renal insufficiency after 60-170 (mean 88.12 +/- 28.23) months of observation. ESRF rate was 11.6% in this group of patients. Eight patients died (2 died of infections and 6 died of ESRF) during the follow-up period. At the beginning of the study the rates of hypertension, persistent anemia and hematuria in Group II were 50%, 70%, and 70% respectively, being much higher than those in Group I. The calculation of AI and CI in 60 patients revealed that there were 65% of patients with AI > or = 7 and 70% of patients with CI > or = 3 in Groups II and III, while in Group I there were only 32% of patients with AI > or = 7 and 19% of patients with CI > or = 3. Sixteen cases had pathologic class changed in 48 repeated biopsies. Seven cases changed to Class IV, 5 to Class II, 3 to Class V from other classes and one to class III from Class II. CONCLUSIONS: Factors associated with the development of renal insufficiency in these lupus patients included hypertension, anemia and hematuria. Renal biopsy evaluation offered additional prognostic information and showed that patients with severe active and chronic histologic changes were at risk for developing renal insufficiency. During the clinical course, the renal classification of LN changed in certain patients, thus the histologic classification of renal morphology at initial presentation did not fully predict the outcome. Renal involvement is very common in systemic lupus erythematosis (SLE) patients. Lupus nephritis (LN) is the most common form of secondary renal disease in China. It has various and unpredictable clinical features. The risks associated with its treatment have challenged investigators to detect the factors which may influence the survival rate of patients with LN and to develop the rational approaches to therapy. Decades of intensive investigation at many centers around the world had underscored the predictive value of demographic, clinical and laboratory data prior to treatment. Controversies still existed due to the difference in environment, race and the selection criteria of patients as well as the method used to evaluate the outcome. There are still some factors which are thought to have an impact on the prognosis of LN. Most of the articles on the prognosis of patients with LN were reported from Europe and America either about Caucasian or African-American patients. The prognosis of LN and its influence in Chinese patients need more elucidation.

Adult↗
PubMed1997

The relationship between gut-derived endotoxemia and tumor necrosis factor, neopterin: experimental and clinical studies.

OBJECTIVE: To determine the relationship between gut-derived endotoxemia and tumor necrosis factor (TNF), neopterin/biopterin formation following hemorrhage, trauma and burns. METHODS: Rats were subjected to hemorrhagic shock (30 mmHg, 90-180 min) and 40% III degrees thermal injury. Circulating endotoxin, TNF, biopterin levels and liver TNF mRNA expression were measured in animals following acute insults. Also, the subjects of this study included 35 patients with burn size greater than 30%, and 25 patients with multiple injuries (n = 18) and major surgery (n = 7). RESULTS: It was found that significant portal and systemic endotoxemia took place in the control animal after hemorrhagic shock and thermal injury, but almost not in the animals that treated by measures aiming at controlling endotoxin/bacteria translocation, including polymyxin B, monoclonal antibody against core lipopolysaccharide, and selective decontamination of the digestive tract (SDD). Concomitantly, hemorrhage and thermal injury resulted in significant increases in systemic plasma TNF level together with tissue TNF mRNA expression, which were associated with the initial appearance of endotoxin in portal vein. However, anti-endotoxin treatment markedly decreased circulating TNF level as well as peak TNF mRNA expression caused by acute insults. There were also lower serum biopterin values in the SDD-treated group as compared with the control group on day 5 postburn. On the other hand, the results showed that the amounts of plasma endotoxin in patients increased during the early stages following major burns, which was significantly correlated with plasma TNF levels, particularly in patients who developed sepsis and multiple organ failure. Although the presence of early endotoxemia did not influence the alterations in serum neopterin, patients with endotoxemia had much higher neopterin values than those who showed no endotoxemia from the second week onward. CONCLUSION: These results suggest that gut-derived endotoxemia could account, at least in part, for the inflammatory mediators formation and release, which might be involved in the pathogenesis of sepsis and multiple organ dysfunction following severe hemorrhage, trauma and burns.

Adult↗
PubMed1997

[Effects of amniotic fluid embolism-like plasma on isolated perfused rabbit lungs].

OBJECTIVE: In order to investigate whether amniotic fluid could induce the release of mediators from blood cells which would damage the lungs, an isolated perfused rabbit lung (IPRL) was exposed to amniotic fluid embolism-like plasma (AFEP) and the injury of AFEP to lungs and the protective effects of ibuprofen were studied. METHODS: 10 ml human amniotic fluid and 50 ml heparized rabbit blood were incubated together with or without ibuprofen (600 micrograms) at 37 degrees C for 30 min and centrifuged. Supernatants were taken and were referred to as AFEP or ibuprofen AFEP. IPRL was perfused with AFEP, ibuprofen AFEP, simple amniotic fluid (SAF), supernatant of amniotic fluid (SnAF), rabbit plasma (RP) and control NS. The changes of pulmonary artery pressure (PAP), respiratory pressure (RP) and lung weight were recorded by computer and compared with control NS group. RESULTS: In groups of SAF, SnAF and RP PAPs were slightly elevated (0.13-0.6 kPa, P > 0.05), and lung weights were not changed. AFEP induced the increase of PAP (3.52 +/- 0.64 kPa, P < 0.05) and lung weight (4.0 +/- 1.0 g, P < 0.01) with the development of lung edema. Administration of ibuprofen prevented partially the APEP-induced increase of PAP (1.87 +/- 0.43 kPa, P < 0.05) and lung weight (0.4 +/- 0.3 g, P < 0.01). CONCLUSION: Amniotic fluid may induce the release of mediators from blood cells, and the latter is the important cause resulting in the pathological changes of lungs in amniotic fluid embolism. Ibuprofen may reduce partially the APEP-induced lung injury.

Animals↗
PubMed1997

Loss of KAI1 messenger RNA expression in both high-grade and invasive human bladder cancers.

The molecular mechanisms responsible for metastasis are not fully understood. Recently, expression of the KAI1 gene on human chromosome 11p11.2 was found to be down-regulated in metastatic prostate cancer cell lines compared with normal human prostate, suggesting that KAI1 may be a metastasis suppressor gene. The aim of this study was to investigate whether there is reduced expression of KAI1 in late-stage bladder cancer. Sixty-six paraffin-embedded bladder tissue sections were analyzed for KAI1 mRNA by in situ hybridization. Nineteen of these were from patients with no histological evidence of bladder cancer, and 47 were from papillary transitional cell carcinomas (TCCs); of these, 16 were highly invasive. KAI1 mRNA was highly expressed in the specimens of normal bladder (11 of 11; 100%), inflammatory bladder (5 of 8; 63%), and noninvasive papillary TCCs of grades 1 and 2 (15 of 24; 63%), compared to grade 3 papillary TCCs (1 of 7; 14%) or invasive TCCs (1 of 16; 6%). The differences in expression between local and invasive disease were statistically significant (P </= 0.01, chi2 test). Our results suggest that down-regulation of KAI1 mRNA is significantly associated with invasive bladder cancer and that KAI1 may represent an invasion/metastasis suppressor gene in bladder cancer.

Antigens, CD↗
PubMed1997

Effects of losartan and PD123319 on antigensin II-induced proto-oncogene expression and protein synthesis in cultured neonatal rat cardiac myocytes.

To study the effects of specific angiotension II (Ang II) receptor, type-1 (AT1) antagonist (Losartan) and type-2 (AT2) antagonist (PD123319), on Ang II-induced proto-oncogene expression and synthesis of RNA and protein in neonatal rat cardiac myocytes, we used respectively [3H]-uridine and [3H]-leucine incorporation to measure the rate of RNA and protein synthesis, and analyzed the c-myc mRNA level by Northern blot. We found that an acceleration in the rate of RNA and protein synthesis was observed when exposed to 2.5 x 10(-6) mol.L-1 [Sar1] Ang II for 24 h (P < 0.01). Losartan inhibited the action in a dose-dependent manner. The level of c-myc mRNA was up-regulated to 340% of control by 2.5 x 10(-6) mol.L-1 Ang II, and Losartan (10(-5) mol.L-1) suppressed the increase of c-myc mRNA stimulated by Ang II. PD123319 showed similar inhibition on Ang II-induced RNA and protein synthesis, but did not inhibit c-myc expression. Thus, Ang II-stimulated expression of c-myc is mainly mediated by AT1 receptors, and contributes to cardiac myocyte hypertrophy while AT2 receptors are involved in mediation of cellular growth without altering of c-myc expression.

Angiotensin Receptor Antagonists↗
PubMed1997

[Detection of human cytomegalovirus infection in blood donor population by the polymerase chain reaction].

Samples of peripheral blood from 76 different donors were detected for the presence of human cytomegalovirus (HCMV) DNA by polymerase chain reaction (PCR). The results showed that HCMVs were present in 39 out of 76 blood donors which reached an infection positive rate of 51.3%. In addition, the sensitivity and specificity on PCR were tested, it also indicated that the sensitivity can reach the level of 5fg.microliter-1. The method is simple, rapid, highly sensitive and specificity. It can be considered as a diagnostic measure in clinical detection of HCMV.

Blood Donors↗
PubMed1996

Expression and biochemical characterization of iron regulatory proteins 1 and 2 in Saccharomyces cerevisiae.

Iron-regulatory proteins (IRPs) 1 and 2 are cytosolic RNA-binding proteins that bind to specific stem-loop structures, termed iron-responsive elements (IREs) that are located in the untranslated regions of specific mRNAs encoding proteins involved in iron metabolism. The binding of IRPs to IREs regulates either translation or stabilization of mRNA. Although IRP1 and IRP2 are similar proteins in that they are ubiquitously expressed and are negatively regulated by iron, they are regulated by iron by different mechanisms. IRP1, the well-characterized IRP in cells, is a dual-function protein exhibiting either aconitase activity when cellular iron is abundant or RNA-binding activity when cellular iron is scarce. In contrast, IRP2 lacks detectable aconitase activity and functions exclusively as an RNA-binding protein. To study and compare the biochemical characteristics of IRP1 and IRP2, we expressed wild-type and mutant rat IRP1 and IRP2 in the yeast Saccharomyces cerevisiae. IRP1 and IRP2 expressed in yeast bind the IRE RNA with high affinity, resulting in the inhibition of translation of an IRE-reporter mRNA. Mutant IRP2s lacking a 73 amino acid domain unique to IRP2 and a mutant IRP1 containing an insertion of this domain bound RNA, but lacked detectable aconitase activity, suggesting that the presence of this domain prevents aconitase activity. Like IRP1, the RNA-binding activity of IRP2 was sensitive to inactivation by N-ethylmaleimide (NEM) or 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), indicating IRP2 contains a cysteine(s) that is (are) necessary for RNA binding. However, unlike IRP1, where reconstitution of the 4Fe-4S cluster resulted in a loss in RNA-binding activity, the RNA-binding activity of IRP2 was unaffected using the same iron treatment. These data suggested that IRP2 does not contain a 4Fe-4S cluster similar to the cluster in IRP1, indicating that they sense iron by different mechanisms.

Aconitate Hydratase↗
PubMed1996

Neoplastic transformation of mouse C3H10T1/2 cells following exposure to neutrons does not involve mutation of ras gene as analyzed by SSCP and cycle sequencing.

About 25% of human tumors contain a mutated member of the ras gene family. Neutron exposure is an occupational risk in several work places and while we know that cells exposed to neutrons can become transformed, the molecular basis of this process is not understood. To determine whether neutron-induced cellular transformation involves ras mutation, C3H10T1/2 cells were exposed to a single dose of 5.9 MeV neutrons. Type II and type III foci were isolated and established as cell lines. A total of 34 foci were selected and expanded for analysis of tumorigenicity, chromosomal aberrations and mutations in members of the ras gene family. The presence of mutations in genomic DNA in N-ras or K-ras of each focus was examined by either single-strand conformational polymorphism (SSCP) analysis or by asymmetric PCR coupled cell cycle sequence analysis. Although chromosomal aberrations were detected at metaphase, no alterations in either ras gene were detected. We conclude that in vitro neutron-induced transformation must occur through a mechanism other than ras mutation.

Animals↗
PubMed1996

Cell surface ADP-ribosyltransferase regulates lymphocyte function-associated molecule-1 (LFA-1) function in T cells.

Post-translational modifications are important in regulating the functions of signal proteins. This is well established for intracellular proteins, but little is known in the case of extracellular domains of cell surface molecules. We recently described a cell surface protein, mono-ADP-ribosyltransferase (ADPRT), on cytotoxic T cells and showed that it mediates attachment of ADP-ribose to cell surface proteins. Concomitantly, cytolytic activity and cell proliferation are inhibited. Here we report that one of the principal proteins modified by this enzyme is lymphocyte function-associated molecule-1 (LFA-1). While both chains are ADP-ribosylated on the extracellular domain of the molecule, persistence of the modification differs between the chains. Label is released from the beta-chain by 1 h, yet remains for at least 6 h on the alpha-chain. Loss of label is suppressed by phosphodiesterase inhibitors such as ADP-ribose and p-nitrophenylthymidine 5'-monophosphate, pointing to the involvement of this class of enzyme. Modification of LFA-1 requires expression of the cell surface ADPRT and causes the loss of epitopes recognized by alpha- and beta-chain-specific Abs. Concomitantly, the generation of inositol phosphates induced by Ab cross-linking of LFA-1 is significantly inhibited. Consistent with this effect, anti-LFA-1-induced homotypic cell adhesion is also inhibited. These effects are not seen in cells from which the ADPRT was removed by phospholipase C. Moreover, cells lacking the cell surface ADPRT are not inhibited by NAD in the cell adhesion assay, but gain this property upon transfection with the ADPRT gene. It is concluded that the cell surface protein mono-ADPRT regulates LFA-1 functions.

ADP Ribose Transferases↗