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Biomedical subjects

Y Jiang

Publications and source records attributed to Y Jiang.

At least 613 records · Page 34Linked to original sources
PubMed1994

[Treatment of the lesions at anterolateral area of the brain stem via far-lateral approaches].

Based on our 12 cases of lesions located at anterolateral area of brain stem which were successful operated upon via far-lateral approaches, the study and progress of the far-lateral approaches were reviewed. In our cases, there were 4 intramedullary lesions including 3 vascular malformations, and 1 glioma. The other 8 lesions were located at extramedullary anterolateral area of brain stem including 2 large acoustic neuromas, 2 meningiomas at clivus and 2 neurofibromas at anterolateral areas of the medulla oblongata and upper spinal cord, 1 teratoma at the anterolateral area of pone-medulla and 1 large aneurysm at the junction of vertebrobasilar artery. During the operations, 8 lesions were totally removed. 1 meningioma was subtotally removed. 2 (1 vascular malformation and 1 glioma) were subtotally removed too, the aneurysm was only given a decompression of increased intracranial pressure, because the patient's interrupted respiration during the operation. There were nooperative mortality and morbidity and good results were obtained in this group. The details of our modified far-lateral approach was also described in this paper.

Adolescent↗
PubMed1994

[Single calcium channel analysis and electron spin resonance (ESR) spectral study on the myocardial effects of ginsenoside Rb2].

Based on the patch clamp technique, the effect of ginsenoside Rb2 on the single channel activity of Ca2+ was observed through the single ventricular myocytes of Wistar rats. Electron spin resonance was used to measure the free radical contents of cultured cardiomyocytes. It is proved that Rb2 can inhibit the activities of single calcium channel and significantly antagonize the increase of free radical contents induced by xanthine-xanthine oxidase.

Animals↗
PubMed1994

[Establishment of a human pancreatic adenocarcinoma cell line(JF305) with p53 expression].

A human pancreatic cancer cell line(JF305) was established from a pancreatic adenocarcinoma xenograft in nude mice. These cells have passed 103 passages in more than 1 year. The plating efficiency was 30.6%, and doubling time was 49.5 hours. Chromosomal analysis showed a human karyotype with a chromosome number between 66-130. JF305 cells exhibited epithelial morphologic features resembling the structure of the original tumor, and they grew to born tumor when inoculated again into nude mice. With immunohistochemical staining, the nuclei of JF305 cells were positive for p53. Therefore, JF305 offer a good model for the study of human pancreatic adenocarcinoma and P53 gene mutation.

Adenocarcinoma↗
PubMed1994

[Effects of the combination of Astragalus membranaceus (Fisch.) Bge. (AM), Angelica sinensis (Oliv.) Diels (TAS), Cyperus rotundus L. (CR), Ligusticum chuangxiong Hort (LC) and Peaonìa veitchii lynch (PV) on the hemorheological changes in "blood stagnating" rats].

The "blood stagnating" rat model was built with adrenaline and cold stimulation. Its hemorrheological character was an increase in the viscosity, thickness and liability to coagulate. The experimental result showed that AM and TAS could decrease the whole blood specific viscosity, but at the same time increase the plasma specific viscosity. The qi-regulating drug CR and two blood-activating drugs LC and PV could improve the hemorrheological changes in "blood stagnating" rats. The combination of qi-regulating drugs and blood-activating drugs had more favorable effect.

Animals↗
PubMed1994

[The observation of therapy of anemia in chronic renal failure with recombinant human erythropoietin].

Anemia is one of the serious complications of chronic renal failure, therapy with recombinant human erythropoietin (r-HuEPO) can correct such anemia officiently. For most patients, the initial dose of r-HuEPO is 100U/kg, by intravenously or subcutaneous, three times a week. After 6 weeks of treatment, Hb could increase to 100g/L, and Hct to above 0.33-0.35. Then 500/kg 3 time a week can be used as maintaining dose. 4 patients need maintaining dose of 150U/kg, for pulmonary infection, poor nutrition, and poor iron supply. Therefore, during the treatment, iron folie acid and Vit B12 should be applied sufficiently and treat the infection effectively with the increasing of Hb and Hct, 2/3 of the patients have hypertension which can be controlled with medication. If there is thrombosis in the dialyzer, the dose of heparin should be increased. The patients on r-HuEPO should be dialysised sufficiently to prevent hyperkalemia.

Adult↗
PubMed1994

[The immunohistochemical study of p53 protein in primary lung cancer].

The expression of tumour suppressor gene P53 products-P53 protein in patients with primary lung cancer has been studied by ABC immunohistochemical method using McAb 1801 as probe. Abnormalities in P53 expression were found in 63 of 78 carcinomas, 23 of 26 squamous cell carcinomas, 23 of 29 adenocarcinomas, 7 of 11 large cell carcinomas, 7 of 9 small cell carcinomas and all 3 cases of adenoid cystic carcinomas showing abnormal P53 expression, whereas no expression of P53 was detectable in 11 normal lung samples. These findings suggest that the pathogenesis of lung cancer may also be related with abnormalities of P53 gene.

Adenocarcinoma↗
PubMed1993

Transcriptional and posttranscriptional regulation of the expression of the erythropoietin receptor gene in human erythropoietin-responsive cell lines.

With erythroid differentiation, committed progenitor cells acquire the ability to respond to erythropoietin (Epo). Epo interacts with target cells through the Epo receptor (Epo-R), whose expression is tightly regulated in a lineage-specific fashion. Epo-R expression is presumed to be progressively activated or repressed as cells progress along the erythroid or the myeloid pathway, respectively. Little is known of the mechanisms that underlie the erythroid-specific expression of the Epo-R gene. GATA-1, the major known transcription factor involved in Epo-R gene regulation, is not erythroid-specific. We have studied the regulation of the expression of the Epo-R gene in two related human Epo-responsive cell lines, UT-7 and UT-7 Epo. These lines express Epo-R at high levels because of amplification of the endogenous gene, which is apparently not rearranged. Treatment for 6 to 24 hours with the tumor promoter, phorbol myristate acetate (PMA), or 24 hours of growth factor starvation (Epo or granulocyte/macrophage colony-stimulating factor [GM-CSF]) decreased or increased the levels of Epo-R mRNA, respectively. In the case of growth factor starvation, the increase (approximately equal to threefold) in the level of Epo-R mRNA correlated directly with an increase in the rate of Epo-R gene transcription as measured by run-off assay. Both increases were observed as early as 3 hours after the growth factor was withdrawn and were reversible; levels of mRNA and transcription rates returned to baseline 3 hours after the cells were reexposed to growth factors. The changes in Epo-R expression after growth factor starvation were coordinated with changes in the level of expression of GATA-1 that were detected both at the mRNA and at the gene transcription level under these conditions (suggesting that GATA-1 was responsible for this upregulation). During PMA treatment, after a transient increase in Epo-R mRNA at 1 hour, a progressive decline in the level of Epo-R mRNA was observed; the level of Epo-R mRNA decreased by 50%, and fell below the level of detection by 6 and 24 hours, respectively. This decrement was explained in part by a fourfold reduction in the rate of gene transcription as well as a reduction (measured as levels of Epo-R mRNA in the presence of actinomycin D) in mRNA stability. The changes in transcription rate occurred in the absence of changes in the level of GATA-1 binding activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Blotting, Northern↗
PubMed1993

Bet2p and Mad2p are components of a prenyltransferase that adds geranylgeranyl onto Ypt1p and Sec4p.

Three different prenyltransferases have been identified in yeast and higher cells, the farnesyltransferase and the type I and type II geranylgeranyltransferases (GGTase). The farnesyltransferase and GGTase-I modify peptides in vitro with the CAAX (C, Cys; A, aliphatic residue; X, terminal amino acid) consensus motif. These enzymes are heterodimers that have different beta-subunits and a shared alpha-subunit. In yeast, the RAM2 gene encodes this alpha-subunit. RAM2 is also homologous to MAD2, a yeast gene whose product has been implicated in the feedback control of mitosis. We have shown that Bet2p is a component of the yeast GGTase-II (refs 6, 12) that geranylgeranylates Ypt1p, a small GTP-binding protein that mediates transport from the endoplasmic reticulum to the Golgi complex. Here we report that Mad2p is a component of this enzyme. Bet2p forms a complex with Mad2p that appears to bind geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate. The efficient transfer of geranylgeranyl onto small GTP-binding proteins requires the presence of an additional activity.

Alkyl and Aryl Transferases↗
PubMed1993

Effects of steroid hormones and opioid peptides on the growth of androgen-responsive Shionogi carcinoma (SC115) cells in primary culture.

We investigated the effects of dihydrotestosterone (DHT), hydrocortisone (HC), basic fibroblast growth factor (bFGF), and opioid peptides on the growth of cells from the androgen-responsive Shionogi mouse mammary carcinoma (SC115) in primary culture. Androgen-responsive SC115 tumor cells were stimulated to grow in response to DHT, HC, and bFGF in a dose-responsive manner in both serum-containing and serum-free media. Moreover, anti-bFGF antibody had a marked inhibitory effect on DHT- and bFGF-induced growth. Three opioid agonists, beta-endorphin (beta-EP), cyclazocine, and morphine sulfate, markedly inhibited SC115 tumor cell growth at concentrations ranging from 10(-11) to 10(-7) M in serum-containing medium with or without DHT, HC, or bFGF, with the greatest inhibition occurring in medium with DHT. In serum-free medium, beta-EP had no inhibitory effects on cell growth. However, beta-EP at concentrations of 10(-9) M or greater significantly inhibited cell growth in serum-free medium containing DHT, HC, or bFGF, with the greatest inhibition again occurring in medium with DHT. Naloxone (10(-8) and 10(-6) M), an opioid receptor antagonist, blocked the inhibitory effects of beta-EP and morphine sulfate. These results suggest that SC115 tumor cells in primary culture are stimulated to grow in a dose-responsive manner by DHT, HC, or bFGF in both serum-containing and serum-free media. It appears that bFGF may mediate, at least partially, DHT-stimulated cell growth. In addition, the opioid peptide system may be involved in regulating endocrine control of growth of the androgen-responsive SC115 carcinoma. The dose-responsive inhibitory effects of opioids and their reversal by naloxone suggest that these effects may be mediated by opioid receptors.

Animals↗
PubMed1993

Smith-Fineman-Myers syndrome: report on a large family.

Smith-Fineman-Myers syndrome is considered an X-linked mental retardation (XLMR) syndrome. Three families have been reported to date. However, none presented a typical pattern of X-linked inheritance. Here we reported on 5 males with Smith-Fineman-Myers syndrome with similar phenotypic expression as in those cases reported previously; they were distributed in 4 sibships of one large maternal kindred. This finding adds strong support to the hypothesis of the Smith-Fineman-Myers syndrome being a rare XLMR syndrome.

Child↗
PubMed1993

Activation of the hydroxylase of sMMO from Methylococcus capsulatus (Bath) by hydrogen peroxide.

Hydrogen peroxide can activate the non-heme binuclear iron-containing hydroxylase of soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath) in the catalysis of oxidation of methane and other sMMO substrates. The reductase, protein B, O2 and NADH are normally required for catalytic activity, but can be replaced by H2O2 serving as the source of both oxygen and electrons for the reaction. Similar results have been observed in a different strain of MMO from Methylosinus trichosporium OB3b (Andersson, K.K., Froland, W.A., Lee, S.-K. and Lipscomb, J.D. (1991) New J. Chem. 15, 410-415). The Km,app for H2O2 was found to be 66 mM. Labelled oxygen experiments show that the oxygen atom in the product in the peroxide driven system is derived from H2O2 and not O2. Using C2-C5 alkanes and 2-butene as substrates it was shown that the product distribution differed in the complete sMMO and H2O2-driven systems, indicating that more than one pathway is available to the enzyme. Protein B, which is required for catalytic activity in the complete system, was found to be an inhibitor of the hydroxylase/H2O2 system. It was also observed that protein B not only affected the activity, but also the selectivity of carbon hydroxylation with 2-methylbutane as substrate.

Dose-Response Relationship, Drug↗
PubMed1993

A common ATP requirement for open complex formation and transcription at promoters containing initiator or TATA elements.

The involvement of ATP during transcription initiation from three basic types of RNA polymerase II promoters was investigated. Hydrolysis of the beta-gamma bond of ATP was found to be required for transcription at TATA, initiator, and initiator + TATA promoters. For all three promoters, ATP is required to melt the transcription start site region during formation of a functional open transcription complex. The use of ATP to open the DNA strands occurs rapidly. The resulting open complex is transient, since the start site re-closes rapidly upon initiation. The requirements for efficient open complex formation were similar to those for transcription in that both upstream elements and a basal element, either TATA or initiator, were necessary. The results further suggest that TATA-dependent and initiator-dependent preinitiation complex assembly pathways converge, prior to a step in which the strands are rapidly opened in the presence of ATP, to form analogous open complexes.

Adenosine Triphosphate↗
PubMed1993

Copper and iron are mobilized following myocardial ischemia: possible predictive criteria for tissue injury.

Direct evidence for substantial mobilization of copper in the coronary flow immediately following prolonged, but not short, cardiac ischemia is presented. In the first coronary flow fraction (CFF) of reperfusion (0.15 ml), after 35 min of ischemia, the level of copper (as well as of iron) was 8- to 9-fold higher than the preischemic value. The levels in subsequent CFFs decreased and reached the preischemic value, indicating that both metals appear in a burst at the resumption of coronary flow. When the first CFF was used in a reaction mixture containing ascorbate and salicylate, the latter underwent chemical hydroxylation and was converted to its dihydroxybenzoate derivatives. Likewise, this CFF promoted the ascorbate-driven DNA degradation. Subsequent 150 CFFs were serially collected and demonstrated low activities. Following 18 min of ischemia, the copper level in the first CFF of reperfusion was only 15% over the preischemic value. In contrast, the mobilization of iron into coronary flow was significant but markedly lower than after 35 min. The levels of copper and the redox activity of the first CFF correlated well with the degree of loss of cardiac function, after 18 and 35 min of ischemia, respectively. After 18 min of ischemia, cardiac function was about 50% and the damage is considered reversible, whereas after 35 min the functional loss exceeded 80% and is considered irreversible. These results are in accord with the causative role that copper and iron can play in heart injury following ischemia, by virtue of their capacity to catalyze the production of hydroxyl radicals, and could lead to the development of new modalities for intervention in tissue injury.

Animals↗
PubMed1993

Pharmacognosy of Mimosa tenuiflora (Willd.) Poiret.

A chemical investigation of the bark of Mimosa tenuiflora (Willd.) Poiret, performed in our laboratory, allowed the isolation and identification of three new triterpenoid saponins (mimonosides A, B and C), three steroid saponins (3-O-beta-D-glucopyranosyl campesterol, 3-O-beta-D-glucopyranosyl stigmasterol and 3-O-beta-D-glucopyranosyl beta-sitosterol) together with lupeol, campesterol, stigmasterol and beta-sitosterol. The three new triterpenoid saponins were subjected to in vitro biological tests (immunomodulation and proliferation) using different animal and human cells in culture. The results of these tests contribute to explain the traditional use of this plant material.

Animals↗
PubMed1993

Bolus contaminant dispersion in oscillatory tube flow with conductive walls.

Dispersion of a bolus contaminant in a straight tube with oscillatory flows and conductive walls is solved by using a derivative-expansion method. Using asymptotic methods when small conductance exists, the axial dispersion, as measured by the time-averaged effective diffusivity, increases over the insulated case, as long as the dimensionless frequency (Womersley parameter), alpha, is smaller than a critical value. When alpha exceeds this value, axial dispersion is diminished by wall conductance. The functional dependence of this critical alpha on the system parameters is investigated. We examine the radial wall transport both for total mass and localized flux, which is found to be independent of velocity field, and compute the time-dependent total mass of wall transport and asymptotic Sherwood number for large times as a function of the wall conductance.

Air Pollutants↗
PubMed1993

[A stick type filter unit for prevention of biohazard in a research laboratory].

It is important to prevent unexpected laboratory infections in a biosafety area. It is recommended that extreme caution should be used when handling needles and syringes to avoid autoinoculation, and that needles and syringes should be used only when there is no alternative. To remove cells and cell debris, a disk-type microfilter unit, which is recommended using a needle, has been used for filtrating supernatant from HIV-1-infected cell cultures. We compared a stick-type microfilter unit, which can be used without a needle, with a disk-type one for their safety and recovery of human immunodeficiency virus particle after filtration. To confirm the right of our comparison, we observed the filter electron microscopically for the virus particles and virus suspensions were carried out and discussed. In conclusion, the stick-type filter should be improved, since the filter unit is inferior to the disk-type filter unit in purification of the virus, but for the safety is superior to the disk-type.

Acquired Immunodeficiency Syndrome↗