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Biomedical subjects

Y Yan

Publications and source records attributed to Y Yan.

At least 289 records · Page 16Linked to original sources
PubMed1995

Respiratory control in heart muscle during fatty acid oxidation. Energy state or substrate-level regulation by Ca2+?

Fatty acids are the main fuel for the myocardium in vivo. They increase oxygen consumption, but the regulation of their beta-oxidation is not well known. Since Ca2+ and matrix volume have been implicated in the regulation of fatty acid oxidation in liver mitochondria, we set out to investigate the effects of Ca2+ on cellular respiration and energetics in the isolated perfused rat heart when oxidizing a short-chain fatty acid. Infusion of hexanoate increased oxygen consumption, while stepwise changes in the perfusate Ca2+ concentration in the range 0.5-2.5 mM caused the mechanical work output and oxygen consumption to change in parallel. Hexanoate addition increased the cellular energy state as determined by 31P NMR and evaluated from the cytosolic [ATP]/[ADP][Pi] ratio. During fatty acid infusion the energy state decreased slightly upon Ca(2+)-induced inotropy, and after discontinuation of the hexanoate infusion the de-energization was more pronounced. The fatty acid caused an extensive partially reversible reduction of flavoproteins and NAD with a slight tendency for oxidation during Ca(2+)-induced inotropy. The data are in agreement with the notion that oxygen consumption during fatty acid oxidation is mainly determined by the energy expenditure, even in the presence of Ca(2+)-induced alterations in the inotropic state. The constancy of the redox states of mitochondrial flavins and NADH/NAD during large changes in oxygen consumption is interpreted as indicating stabilization of the mitochondrial redox states by Ca(2+)-linked regulation.

Adenosine Diphosphate↗
PubMed1995

Nucleotide sequence and expression of the genes for the alpha and beta subunits of phycocyanin in Cyanidium caldarium.

The nucleotide sequence of the plastid-encoded operon containing genes for the alpha (cpcA) and beta (cpcB) subunits of phycocyanin in the unicellular red alga Cyanidium caldarium is described. cpcB is located 5' to cpcA and the two genes are separated by a 102-bp spacer region. The transcription start site of cpcBA was mapped to 80 bp upstream of the ATG initiation codon of cpcB. Promoter-like elements similar to the -10 (TATAAT) and -35 (TTGACA) consensus promoters in bacteria were found 6 and 31 bp upstream of the transcription initiation site. Northern blotting revealed an abundant 1.3-kb cpcBA transcript in illuminated cells, but this transcript was undetectable in dark-grown cells. Expression levels of cpcBA in cells incubated with 10(-6) M heme in the dark were similar to those in cells illuminated for 24 h. Cells illuminated with 150 microM gabaculine (an inhibitor of delta-aminolevulinate synthesis) or 10 mM levulinic acid (an inhibitor of delta-aminolevulinate dehydrase) lacked detectable cpcBA transcripts. In cells illuminated with 200 microM N-methyl-mesoporphyrin IX (an inhibitor of ferrocheletase), inhibition of cpcBA expression and phycocyanin synthesis was similar. These results provide strong evidence that light induction of the cpcBA operon is dependent on synthesis of heme.

Amino Acid Sequence↗
PubMed1995

Cross-reactivity of Rickettsia japonica and Rickettsia typhi demonstrated by immunofluorescence and Western immunoblotting.

Cross-reactivity between Rickettsia japonica and R. typhi was observed by immunofluorescence tests using sera from patients with Oriental spotted fever (OSF), from whom the causative agent was isolated and identified as R. japonica. Western immunoblotting with these sera revealed that only the 120-kilodalton surface polypeptide, i.e., rickettsial outer membrane protein (rOmp) B, has a common antigenicity with the 105-kilodalton surface polypeptide of R. typhi. In some cases, antibodies specifically reactive with R. typhi were detected in acute-phase sera followed by a significant rise in titers, possibly because of an anamnestic response to a previous infection with an R. typhi-like agent; the sera retained reactivity to R. typhi even after absorption by a homologous strain. A lipopolysaccharide (LPS)-like antigen of R. typhi was found to be reactive with some sera of OSF patients. The ladder bands on Western immunoblot of rickettsial organisms were confirmed to be polysaccharide in nature, which was demonstrated by comparing them with the pattern of silver-stained gel of proteinase K-treated rickettsial specimens after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Antibodies, Bacterial↗
PubMed1995

Detection of Rickettsia japonica in Haemaphysalis longicornis ticks by restriction fragment length polymorphism of PCR product.

PCR was applied to the detection of Rickettsia japonica, the causative agent of Oriental spotted fever (OSF), in ticks collected at two sites of the Muroto area on Shikoku Island, a major area in Japan where OSF is endemic. Primer pair Rr190.70p and Rr190.602n of the R. rickettsii 190-kDa antigen gene sequence of Regnery and others (R.L. Regnery, C.L. Spruill, and B.D. Plikaytis, J. Bacteriol. 173:1576-1589, 1991) primed the DNA extracted from Haemaphysalis longicornis ticks but not those extracted from Haemaphysalis formosensis, Haemaphysalis flava, Haemaphysalis hystricis, or Amblyomma testudinarium ticks. Digestion of the amplification product with the restriction endonucleases PstI and AluI produced the restriction fragment length polymorphism pattern specific to R. japonica. The HindIII and MspI digests gave restriction fragment length polymorphism patterns identical to those of the PCR product from R. japonica DNA. Hemolymph preparations of H. longicornis ticks were demonstrated to contain rod-shaped organisms that were detected by immunofluorescence with the monoclonal antibody specific to R. japonica species. The primer pair did not amplify the DNA of a laboratory colony of H. longicornis ticks originally collected at an area where OSF is not endemic. Our results provided evidence that H. longicornis ticks might be an arthropod reservoir for R. japonica and a vector of OSF.

Animals↗
PubMed1995

Clinical and prognostic significance of bone marrow involvement in patients with diffuse aggressive B-cell lymphoma.

PURPOSE: We studied the effect of morphology and extent of bone marrow (BM) infiltrate on the survival of patients with diffuse aggressive B-cell non-Hodgkin's lymphoma (NHL), along with clinical features. PATIENTS AND METHODS: Sixty adult patients with diffuse aggressive B-cell NHL and BM involvement at the time of presentation were studied. All patients were uniformly staged and treated with a curative high-dose chemotherapy regimen. BM involvement was assessed according to the cytology, pattern of infiltration, and extent of involvement, and was correlated with overall survival (OS) and failure-free survival (FFS). RESULTS: Patients with BM involvement that consisted of > or = 50% large cells or BM involvement of > or = 70% had a poorer OS (P = .065 and P = .055, respectively). Those who presented with an infiltrate of less than 50% large cells and an international prognostic index (IPI) of < or = 3 had a significantly longer postrelapse survival time (P = .003). A diffuse or interstitial pattern of BM involvement was predictive of both poor OS and FFS (P = .008 and .009, respectively). Multivariate analysis indicated that only IPI (P = .0005) and pattern of BM infiltration (P = .009) were independent predictors of OS, and only the former was predictive of FFS (P = .03). CONCLUSION: The IPI is predictive of OS and FFS, while BM involvement with a diffuse or interstitial pattern is associated with significantly poorer OS. Patients with BM infiltration that involved > or = 70% of the marrow or contained > or = 50% large cells had poor OS, but more patients need to be studied to determine the significance. Two parameters, IPI < or = 3 and BM large cells less than 50%, identify a group of patients with long-term survival after relapse.

Adult↗
PubMed1995

[TLC scanning determination of baicalin content in niuhuang qingxin pills].

Baicalin in the samples was extracted with ultrasonic wave, the extract was spotted on thin-layer plates of gel GF254 and developed with the mobile phase consisting of toluene-ethylacetate-formic acid (2:3:2.2). Determinations were carried out with Shimadzu CS-930 TLC scanner with lambda s = 280 nm and lambda R = 207 nm. The linear range was 0.46-4.6 micrograms/ml. The average recovery of baicalin from the samples was 98.35%, RSD = 2.82%.

Anti-Infective Agents↗
PubMed1995

Changes of immune functions after radiation, burns and combined radiation-burn injury in rats.

The changes of several immune functions were observed in rats after they were inflicted with 6 Gy gamma rays irradiation, 15% TBSA full thickness brun and the combination of the 2 injuries. It was found that the functions of thymocytes and splenoctyes suffered the most severe suppression in the 24th to 72nd hour after radiation injury and began to recover on the 7th day. In the rats with burn injury, the suppression on thymocytes and splenocytes were significantly less severe than that after radiation and recovered more rapidly. The effects of combined radiation-burn injury showed several characteristics. The suppression on the thymocytes was more severe with slower recovery as compared with that after single radiation injury only. The suppression on the splenocytes as a whole was similar to that after single radiation injury, but in the early stage after combined injury, the suppression was far more severe than that after radiation. Escharectomy and skin grafting on the burn wounds on the 1st day after combined injury could accelerate the recovery on both the thymocytes and splenocytes. Our findings indicated that the severity of the suppression on the immune functions due to combined radiation-burn injury might depend on the size of the burn wounds.

Animals↗
PubMed1995

[The damaging effect of activated human neutrophils on isolated perfused rat lungs--the role of elastase].

Human neutrophil and its elastase play an important role in the pathogenesis of various lung diseases. We investigated the damaging effect of human neutrophils stimulated with PMA (phorbol myristate acetate 10ng/ml) or calcium ionophase A23187 (2ng/ml) on isolated perfused rat lungs. The study specimens consisted of 4 groups of animals. A control, B perfused with human neutrophils, C perfused with human neutrophils stimulated with PMA, and D perfused with human neutrophils stimulated with A23187. By using the ELISA method, we found that the level of human neutrophil elastase (HNE) in perfusate increased significantly at 30min (1.68 +/- 0.79ng/ml P < 0.05) and 60min (2.35 +/- 0.87 ng/ml P < 0.01) after PMA stimulating, but the HNE in the lung lavage fluid of the same group only slightly increased and the concentration of protein in lavage fluid did not change. After stimulating with A23187, the concentration of HNE in perfusate increased markedly at 30min (4.03 +/- 1.96ng/ml P < 0.01) and maintained at high level (P < 0.01). There was a significant increase of HNE level in lung lavage fluid (2.49 +/- 0.61ng/ml) from group D rat lungs, compared with group A, B or C, and the protein as well (1.61 +/- 0.58mg/ml P < 0.05). All the results indicate that the stimulated human neutrophils can release elastase in perfused rat lung. Neutrophil stimulated with A23187 can increase pulmonary permeability and injure the lung. We suggest that the lung damage, caused by human neutrophils, may be the effect of neutrophil elastase or the synergistic effect with some other substances derived from neutrophil.

Animals↗
PubMed1995

[Comparative study of diagnostic standards of eye-signs in blood stasis syndrome and of blood stasis syndrome].

By virtue of a diagnostic study of 781 cases on the basis of six standards, it was shown that for the effectiveness in diagnostic positive rate, sensitivity, specificity, false positive rate, false negative rate and comprehensive scoring, the International Diagnostic Standards for Blood Stasis Syndrome (BSS) and Chinese Diagnostic Standards for BSS were the best ones, BSS Eye-Signs and Japanese BSS Diagnostic Standards were the second, trial program of International Stasis Diagnostic Standards and Zhongshan's BSS tenderness points came the third. Each standard has its unique advantage and therefore, we should take the other's advantage to offset one's weakness. The causes of their weakness have been discussed and the rational recommendation for their application has been proposed.

Blood Viscosity↗
PubMed1995

[Changes of collagen distribution in extrapulmonary arteries of hypoxia-induced pulmonary hypertensive rat].

Changes of collagen distribution in extrapulmonary arteries induced by hypoxia and the effects of ligustrazine (ligus) and 764-3 were investigated. Histological study showed that hypoxia could induce an increase of the medial and adventitial thickness of the pulmonary arterial trunk. An increase of type I and type III collagen fibers in pulmonary arterial trunk, particularly the increase of type III collagen fibers in adventitia of the pulmonary trunk were revealed by picrosirius-polarization methods. Ligus partially prevented the increase of type I and III collagen fibers of pulmonary arterial trunk. Electron microscopy showed that both the medial smooth muscle and adventitial fibroblasts were hypertrophic and hyperplastic, and the surrounding collagen fibers were increased.

Altitude Sickness↗
PubMed1995

[A primary observation on the effect of cell fusion on metastatic potential of tumor cells].

Mouse spleen cells transfected with pSV2 neo by CaPO4 precipitation were fused with highly metastatic cell clone (PLA801-D95) from human large cell lung cancer cell line. Hybrid cell clone PMS-2 was obtained after G418(400/ml)selection. After injection of 7 x 10(6) PMS-2 cells into nude mice, there was a tumor nodule developed, but the metastatic foci could not be found while 3 x 10(6) PLA801-D95 cells would metastasize to lung and lymph nodes after they were injected into nude mice. It might indicate that sometime mouse spleen cells could not suppress tumor formation but the metastatic potential could be suppressed by the fusion of mouse spleen cells with the lung cancer cells. The results of growth curve, serum independence and incorporation rates of H-thymidine all showed that the growth rates of parental cells were higher than those of PMS-2. Our data suggest that suppression of tumorigenicity and metastatic potential could be controlled by different kinds of genes, and the cloning of metastasis suppressor gene by subtractive hybridization is ongoing in our laboratory.

Animals↗
PubMed1995

[Analysis of therapeutical effectiveness in 35 cases of acute leukemia with therapy of Chinese integrated medicine].

Thirty-five cases of acute leukemia were treated with methods of Chinese integrated medicine (CIM), i.e. in the CIM group, in which the complete remission rate, partial remission rate and total remission rate were 68.5%, 20.0% and 88.5%, respectively; while those in the random control group were 42.7%,20% and 62.7%, respectively. The comparison between the two groups showed a significant difference(P < 0.05). The patients' survival period in CIM group of 1,3,5 and above 5 years was shown in 20, 12, 7 and 5 cases, but in the control group, 9,5,0 and 0 cases, respectively. The comparison between the two groups also showed an obvious difference (P < 0.01), which demonstrates that the therapeutic effect was better in the CIM group and the patients' survival period was longer in the CIM group, too.

Adolescent↗
PubMed1995

[Relationship between c-erbB-2 oncoprotein expression and prognosis in salivary gland malignant pleomorphic adenoma].

A monoclonal antibody AB-3 has been used immunohistochemically in a retrospective study of formalin-fixed paraffin embedded tissues of the salivary gland malignant pleomorphic adenomas (MPA). Positive staining was found in 25/60 (41.67%) of MPA. c-erbB-2 oncoprotein expression of the postoperative recurrent MPA group was higher than that of non-recurrent MPA group (P < 0.05). The postoperative 5-year survival rate of MPA with c-erbB-2 expression was considerably lower than that of without expression (P < 0.01). This observation indicates that c-erbB-2 oncoprotein expression may be an useful prognostic indicator in MPA.

Adenoma, Pleomorphic↗