[Improvement of high-frequency jet ventilation method in treating respiratory failure].
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Aged↗
Biomedical subjects
Y X Liu
Publications and source records attributed to Y X Liu.
[Studies on clinical epidemiology of Tsutsugamushi disease of the autumn-winter type in the easten suburbs of Jinan].
This paper reported the epidemiological characteristics of 154 cases under investigation for tsutsugamushi disease of autumn-winter type in the eastern suburb of Jinan. Results showed that the characteristics differed greatly from those in the southern part of China. Majority of patients had toxic symptoms due to infections but specific characteristics were less obvious. Eschars and ulcers appeared only in 14.94% of the cases and occurred only in autumn-winter season. Clinically mild cases constituted the majority. Cases not only distributed sporadically, but also had multi-organ lesions (MOL). Young peasants seemed to be most vulnerable. The pathogen of the disease belonged to low virulent strain. Serological typing belonged to the Gilliam type. The diagnosis and the treatment of the disease were discussed. Specific serum IgG of the disease was detected 6 years after convalescence.
Adolescent↗
Evidence that casein kinase 2 phosphorylates hepatic microsomal calcium-binding proteins 1 and 2 but not 3.
We have extensively purified three of the hepatic microsomal intralumenal Ca2+-binding proteins, CBP1, CBP2, and CBP3, which were originally described by Van et al. [(1989) J. Biol. Chem. 264, 17494-17501]. These apparently homogeneous preparations showed only single 45Ca2+ binding bands. On the basis of the peptide sequence, CBP2 was found to be highly homologous with the previously described protein ERp72. Similarly, CBP3 was identical to calreticulin and CBP1 had some homology to calmodulin. Contrary to the report of Van et al. (1989), we found that CBP2 had little thiol:protein disulfide oxidoreductase activity. Of the three purified preparations, only CBP2 exhibited apparent intrinsic protein kinase activity. This activity was found to be due to contamination of the CBP2 preparation by an extremely low concentration of tightly bound casein kinase 2 (CK2). In line with this observation, the phosphorylation was inhibited by heparin, removed by antibody to CK2, and stimulated by spermine. Furthermore, CBP2 was readily phosphorylated in vitro by added CK2 but only slowly phosphorylated by several other protein kinases. Thus, the persistence of CK2 in a highly purified preparation of CBP2 along with several other lines of evidence presented in this study might suggest that the protein CBP2 is a physiologically relevant substrate for CK2. Furthermore, these data suggest that CK2 might be localized in the lumen of the endoplasmic reticulum and that the phosphorylation of CBP2 in the lumen may play a role in the chaperone activity attributed to this protein.
Amino Acid Sequence↗
Preliminary studies on the role of plasminogen activator in seminal plasma of human and rhesus monkey.
Two types of plasminogen activators (PA), tissue type (tPA) and urokinase type (uPA), were identified in the seminal plasma of both the human and the rhesus monkey. We studied the possible relationship between PA activities in the seminal plasma and the sperm counts and motility and demonstrated that: (i) PA activity in human seminal plasma from infertile patients was associated with immotile spermatozoa; (ii) the treatment of fertile men with testosterone enanthate (TE) to induce azoospermia was accompanied by an increase in seminal PA activity; (iii) when monomer T4 (isolated from multiglycosides of Tripterygium wilforddi) was administered to fertile male rhesus monkeys to induce azoospermia, PA activities in seminal plasma increased considerably; and (iv) immunocytochemistry studies showed that both uPA and PAI-1 antigens were localized on the surface of human spermatozoa, indicating that human spermatozoa were capable of binding uPA and PAI-1 through their receptors or forming a complex. These data demonstrate that seminal PA activity may be related to azoospermia, and possibly, to the fertilizing capability of spermatozoa in primates.
Adult↗
Coordinated expression of tissue-type plasminogen activator and plasminogen activator inhibitor type 1 during corpus luteum formation and luteolysis in the adult pseudopregnant rat.
Proteolytic activity generated by the plasminogen activator (PA) system is associated with many biological processes. Using an adult pseudopregnant rat model, we have studied how two components of the PA system, tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1), are expressed temporally and spatially during different developmental stages of the corpus luteum (CL). Northern blot analysis, in situ hybridization, in situ zymography, and fibrin overlay were used to analyze the expression and distribution of tPA and PAI-1 messenger RNA (mRNA) as well as PA activity in CL of different ages. We demonstrated that during the luteinization period (approximately days 1-2), tPA mRNA was highly and evenly expressed in newly formed CL, whereas PAI-1 mRNA was mainly detected in the central part of the same CL. In accordance with these findings, proteolytic activity generated by tPA was detected in the outer region of newly formed CL by in situ zymography. During the luteotropic period (approximately days 3-10), tPA mRNA expression was very low. PAI-1 mRNA expression was also low, but increased on day 10. As expected, proteolytic activity was very low during this period. During functional luteolysis (days 13-14) and subsequent structural luteolysis, tPA mRNA was elevated. PAI-1 mRNA was also expressed during this period. Moreover, the net PA activity, as determined by fibrin overlay, was relatively high during this period. Our studies indicate that tPA and PAI-1 are coordinately expressed in the CL, resulting in increased proteolytic activities during the luteinization and luteolytic periods. PA-mediated proteolysis may, therefore, play a role in both CL formation and luteolysis in rats.
Animals↗
[Synthetic evaluation of the quality of clinical practice of nursing students].
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Clinical Competence↗
Studies on the role of plasminogen activators and plasminogen activator inhibitor type-1 in rat corpus luteum of pregnancy.
Luteal development and demise are characterized by substantial tissue destruction and remodeling, which is associated with local production of plasminogen activation. Recently we reported involvement of tissue-type plasminogen activator (tPA) in luteolysis in rhesus monkeys. In this study, we further investigated changes in expression of both tPA and urokinase-type plasminogen activator (uPA) activity during various developmental stages of rat corpus luteum (CL) of pregnancy and their possible physiological roles in luteolysis. Rat CL or dispersed luteal cells in vitro are capable of producing both tPA and uPA, and a plasminogen activator inhibitor type-1, in a stage-dependent manner. However, only tPA activity significantly increases in late phases of CL development. Furthermore, the increase in tPA activity in the CL is well correlated with a sharp decrease in luteal progesterone production. Addition of exogenous tPA to the luteal culture considerably decreases progesterone production. In contrast, immunoneutralization of endogenously produced tPA activity by inclusion of tPA monoclonal antibody in the culture results in a significant increase in luteal progesterone production. It is therefore suggested that tPA may also be involved in suppression of rat luteal function. This hypothesis is further supported by the findings that interferon-gamma significantly inhibits luteal basal and hCG-stimulated progesterone production and also stimulates basal and hCG-induced tPA activity. On the basis of the data provided in this study and similar findings in monkeys, we conclude that endogenously produced tPA in late phase of CL development may regulate luteal regression through local autocrine or paracrine action.
Animals↗
Hormonal regulation of tissue-type plasminogen activator and plasminogen activator inhibitor type-1 in cultured monkey Sertoli cells.
Sertoli cells play a central role in the control and maintenance of spermatogenesis. Isolated Sertoli cells of mouse and rat testes have been shown to secrete plasminogen activator (PA) and a plasminogen activator inhibitor type-1 (PAI-1) in culture. In this study, we have investigated the hormonal regulation of PA and PAI-1 activities in cultured monkey Sertoli cells. Sertoli cells (5 x 10(5) cells/well) isolated from infant rhesus monkey testes were preincubated at 35 degrees C for 16 h in 24-well plates precoated with poly(D-lysine) (5 micrograms/cm2) in 0.5 ml McCoy's 5a medium containing 5% of fetal calf serum and further incubated for 48 h in 0.5 ml serum-free medium with or without various hormones or other compounds. PA as well as PAI-1 activities in the conditioned media were assayed by fibrin overlay and reverse fibrin autography techniques respectively. The Sertoli cells in vitro secreted only tissue-type PA (tPA), no detectable amount of urokinase-type PA (uPA) could be observed. Monkey Sertoli cells were also capable of secreting PAI-1. Immunocytochemical studies indicated that both tPA and PAI-1 positive staining localized in the Sertoli cells, spermatids and residual bodies of the seminiferous epithelium; Northern blot analysis further confirmed the presence of both tPA and PAI-1 mRNA in monkey Sertoli cells. Addition of follicle-stimulating hormone (FSH) or cyclic adenosine monophosphate (cAMP) derivatives or cAMP-generating agents and gonadotrophin-releasing hormone (GnRH) agonist or phorbol ester (PMA) to the cell culture significantly increased tPA activity.(ABSTRACT TRUNCATED AT 250 WORDS)
1-Methyl-3-isobutylxanthine↗
[Preventive effect of quinacrine on the development of heat injury by stabilizing membrane phospholipids metabolism and beta-adrenoceptor].
Previous studies have demonstrated that the activation of phospholipase A2 (PLA2) during heat stress would caused disorder of membrane phospholipids metabolism, accompanied by a decrease in phosphatidylcholine and phosphatidyl-serine and an increase in arachidonic acid. In heat stressed rats, a down-regulation of beta-adrenergic receptor in lung tissue was observed due to activation of PLA2. In the present work, it was demonstrated that pretreatment of rats with PLA2 inhibitor, quinacrine (20 mg/kg, I.P.), 1 h before heat stress could block these membrane lipid alterations, and the tolerance of rats to heat exposure was enhanced. The effect of quinacrine on the thermotolerance of marching soldiers with 15 kg of load under hot environment was also investigated. The results indicated that in the soldiers taken orally 200 mg quinacrine 1 h before marching, their heart rate, body temperature, accumulation of blood lactic acid and the changes of index of heart function were significantly improved as compared to the control group at the end of 3 h marching. According to these data, it can be concluded that quinacrine is a useful drug to prevent derangement of beta-adrenoceptor and membrane phospholipids metabolism in the development of heat stress. So as to prevent heat injury, and to improve tolerance to heat stress.
Adolescent↗
[Effect of prolactin on gonadotropin-induced ovarian estrogen and progesterone production in mouse].
Immature mice (21-23 days old) were injected with 8 IU PMSG to stimulate follicle growth and followed 24 h later by either injection of 8 IU hCG alone or hCG plus 100 micrograms of prolactin (PRL). The animals were killed at 3, 12 and 24 h after hCG treatment. The ovaries and blood samples were collected. Granulosa cells were prepared for incubation. Progesterone and estrogen concentrations in both the serum and the culture medium were determined. The results showed that PRL significantly enhanced hCG-induced mouse serum progesterone content, while serum estrogen concentrations were considerably decreased by the co-injection of PRL. Prolactin was also capable of stimulating gonadotropin-induced progesterone secretion in the cultured GC. However, the aromatase activity induced by FSH and hCG was remarkably inhibited by the presence of PRL. These data suggest that PRL inhibition of hCG-induced ovulation may be due to its interference with the gonadotropin-induced estrogen production by the follicular granulosa cells.
Animals↗
Yeast topoisomerase II mutants resistant to anti-topoisomerase agents: identification and characterization of new yeast topoisomerase II mutants selected for resistance to etoposide.
We describe a system that allows us to easily isolate and characterize mutants in yeast topoisomerase II that are resistant to antitumor agents that target this enzyme. The system uses yeast strains that are sensitive to those agents and that carry temperature-sensitive top2 mutations. The temperature-sensitive mutation allows the isolation of recessive drug-resistant mutations. The mutagenized TOP2 gene we have used is under the control of the yeast DED1 promoter; this overexpression of TOP2 is designed to avoid isolating mutants that are drug resistant solely because the mutated topoisomerase II has low enzymatic activity. We describe three mutants that we isolated using this system. Two of the three mutants show resistance to etoposide and amsacrine, while the third mutant is partially resistant to etoposide and fluoroquinolones but not to amsacrine. DNA sequence changes have been identified in all of these mutant TOP2 genes. The mutant with partial resistance to etoposide and fluoroquinolones has an amino acid change at position 738 of TOP2, which is three amino acids from the site homologous to Ser83 of E. coli gyrA, an amino acid which had previously been shown to be an important target for resistance to quinolones in bacteria. One of the alleles that confers resistance to both etoposide and amsacrine, top2-103, has changes in amino acid 824 and amino acid 1186 of TOP2. Reconstruction of the mutations by oligonucleotide-directed mutagenesis demonstrates that the change at amino acid 824 is responsible for the drug resistance of this allele.
Amino Acid Sequence↗
Sequence of the region downstream of the Vitreoscilla hemoglobin gene: vgb is not part of a multigene operon.
The 1668 base pairs (bp) downstream of the Vitreoscilla hemoglobin gene were sequenced in the hope of finding related genes that might be part of an operon. Instead, a sequence was found that constituted an open reading frame (ORF) of 569 amino acids (apparently the carboxy-terminal part of a larger ORF), in the direction opposite to the hemoglobin gene. This sequence was found to have 64% similarity with the 1685 bp at the 3' end of the Escherichia coli uvrA gene. The inferred amino acid sequence of the Vitreoscilla DNA has 69% similarity with the corresponding sequence of the E. coli uvrA protein, with similarities of 90, 100, and 85% in the helix-turn-helix, C-terminal ATP binding, and C-terminal zinc finger domains, respectively. The distance between the 3' ends of the Vitreoscilla hemoglobin and uvrA genes is 63 bp.
Adenosine Triphosphatases↗
[Pathological and immunohistochemical study on anorectal melanoma].
Forty two cases of anorectal melanoma were studied which constituted 1.19% of all the anorectal malignancies collected in this series. 90% of the tumors located near by the dentate line. Grossly, the masses were nodular, fungiform or ulcerated. Histologically, pleomorphic tumor cells mixed together giving a feature somewhat like either carcinomatoid or sarcomatoid, with a predominance of one kind of the malignant cells. Histopathologic observation supported the idea that this tumor developed from the melanocytes and nevus cells located at the basal layer of the epithelium. Immunohistochemistry proved that melanocytes originated from the neural crest. S-100 protein was marker with high sensitivity but the specificity not ideal, so that, varied markers are recommended in order to improve the accuracy of diagnosis.
Adult↗
Molecular epidemiologic study of burn wound infection caused by Staphylococcus aureus in children.
115 children with burn injuries were admitted to the Children's Hospital of Chongqing Medical University. Of the 1554 samples, 276 strains of staphylococcus aureus were isolated from the burn wounds and other sites. The rate of burn wound infection caused by S. aureus was 25.2% (29/115). The 54 epidemic strains of S. aureus all carried 1.6 and 1.9 Md plasmid DNAs belonging to phage type 618, and were resistant to at least 10 antimicrobial agents, including oxacillin, cephalothin and cephaloridine, but sensitive to tobramycin and amikacin. Identical plasmid profiles and phage types of isolated S. aureus indicated that a patient carrying a multi-resistant strain of S. aureus in his anterior nares caused an epidemic of S. aureus wound infection in 13 patients. S. aureus isolated from burn wounds of 8 cases were derived from the contaminated hands of their family members.
Adolescent↗
[Degradation of the constituents in solubilization process of donkey skin].
Dry donkey skin, defatted in advance with hair scraped off, was separately solubilized by heating in sealed tubes at 130 degrees C for 2, 4, 6, 8h. The resultants were clarified and dried as Ejiao, whose yield appeared to reach maximum after 4h heating. Absorptivities of all four Ejiao preparations were in good approximation to standard gelatin. However, their intrinsic viscosity declined in order of prolonged solubilization process, indicating that depolymerization of donkey skin gelatin had taken place. In addition, significant degradation of dermatan sulfate, another constituent of Ejiao, was detected electrophoretically and photometrically.
Animals↗
Coordinated regulation of tissue type plasminogen activator and plasminogen activator inhibitor type-1 gene expression in hypophysectomized rat ovaries during GnRHa-induced ovulation.
In this study we have demonstrated that both granulosa and theca-interstitial cells of hypophysectomized rat ovaries are capable of synthesizing tPA and PAI-1. Injection of a GnRH agonist can markedly induce these gene expressions in the ovary in a cell-specific and time-coordinated manner, so that a surge of tPA mRNA and its activity in both granulosa and theca-interstitial cells was obtained just prior to ovulation. Theca-interstitial cells make PAI-1 become the most active in the ovary. Both the amount PAI-1 mRNA and its activity in the cells reach the maximum level 6 h before the tPA peak. By contrast, granulosa cells produce only a little amount of PAI-1 (most increase tPA activity), and both PAI-1 mRNA and activity in the cells reach the maximum after ovulation. The coordinated regulation of tPA and PAI-1 in the ovary may fine-tune the peak of tPA activity which may be important for the regulation of the ovulatory process. The changes of tPA and PAI-1 in the ovarian cells of hypophysectomized rats during GnRHa-induced ovulation are similar to that in intact rats during hCG-induced ovulation, suggesting that the ovulatory process can be modulated by different regulatory signals mediated by influencing the coordinated expression of both tPA and PAI-1.
Animals↗
[Comparison of protein assays for ejiao].
Ejiao exhibits identical spectral characteristics with those of reference gelatin in Murphy's UV spectrophotometry and color-yielding reactions performed according to Gornall's biuret and Lowry's Folin phenol procedures respectively. Results of protein assays of Ejiao measured by above-mentioned photometric methods were in good approximation to each other using gelatin as standard and comparable with that of Kjeldahl nitrogen determination.
Materia Medica↗
[Clinical analysis of 72 epileptic patients treated with alkaline extract of Euphorbia fisheriana].
The effect of 72 epileptic patients treated with alkaline extract of Euphorbia fisheriana (EF) was reported. 22 of them with intractable epilepsy were compared with the treatment of both single-blind and placebo. The results showed that the total effective rate with EF was 78%, its marked effective rate was 42% and the effective rate 36%. The epileptic patients reduced their frequency of seizures significantly (P < 0.05), while the effective rate of 22 epileptic patients with single-blind treatment was 59%, and that with placebo was 32%. There was a significant difference between the two groups (P < 0.05). The active principle of Euphorbia fisheriana was Euphorbia alkaloid. There was no obvious adverse effect in clinical observation. It is considered that Euphorbia fisheriana is rich in resource, cheap, and with marked anticonvulsant effect.
Adolescent↗