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Biomedical subjects

Q Lu

Publications and source records attributed to Q Lu.

At least 181 records · Page 10Linked to original sources
PubMed1997

Inhaled nitric oxide in acute respiratory distress syndrome with and without septic shock requiring norepinephrine administration: a dose-response study.

BACKGROUND: The aim of this prospective study was to assess whether the presence of septic shock could influence the dose response to inhaled nitric oxide (NO) in NO-responding patients with adult respiratory distress syndrome (ARDS). RESULTS: Eight patients with ARDS and without septic shock (PaO2 = 95 +/- 16 mmHg, PEEP = 0, FiO2 = 1.0), and eight patients with ARDS and septic shock (PaO2 = 88 +/- 11 mmHg, PEEP = 0, FiO2 = 1.0) receiving exclusively norepinephrine were studied. All responded to 15 ppm inhaled NO with an increase in PaO2 of at least 40 mmHg, at FiO2 1.0 and PEEP 10 cmH2O. Inspiratory intratracheal NO concentrations were recorded continuously using a fast response time chemiluminescence apparatus. Seven inspiratory NO concentrations were randomly administered: 0.15, 0.45, 1.5, 4.5, 15, 45 and 150 ppm. In both groups, NO induced a dose-dependent decrease in mean pulmonary artery pressure (MPAP), pulmonary vascular resistance index (PVRI), and venous admixture (QVA/QT), and a dose-dependent increase in PaO2/FiO2 (P </= 0.012). Dose-response of MPAP and PVRI were similar in both groups with a plateau effect at 4.5 ppm. Dose-response of PaO2/FiO2 was influenced by the presence of septic shock. No plateau effect was observed in patients with septic shock and PaO2/FiO2 increased by 173 +/- 37% at 150 ppm. In patients without septic shock, an 82 +/- 26% increase in PaO2/FiO2was observed with a plateau effect obtained at 15 ppm. In both groups, dose-response curves demonstrated a marked interindividual variability and in five patients pulmonary vascular effect and improvement in arterial oxygenation were dissociated. CONCLUSION: For similar NOinduced decreases in MPAP and PVRI in both groups, the increase in arterial oxygenation was more marked in patients with septic shock.

Journal Article↗
PubMed1997

Sperm from beta 1,4-galactosyltransferase-null mice are refractory to ZP3-induced acrosome reactions and penetrate the zona pellucida poorly.

A variety of sperm surface components have been suggested to mediate gamete recognition by binding to glycoside ligands on the egg coat glycoprotein ZP3. The function of each of these candidate receptors is based upon varying degrees of circumstantial and direct evidence; however, the effects on fertilization of targeted mutations in any of these candidate receptors have not yet been reported. In this paper, we describe the effects of targeted mutations in beta1,4-galactosyltransferase, the best studied of the candidate receptors for ZP3. Surprisingly, galactosyltransferase-null (gt[-/-]) males are fertile; however, sperm from gt(-/-) males bind less radiolabeled ZP3 than wild-type sperm, and are unable to undergo the acrosome reaction in response to either ZP3 or anti-galactosyltransferase antibodies, as do wild-type sperm. In contrast, gt(-/-) sperm undergo the acrosome reaction normally in response to calcium ionophore, which bypasses the requirement for ZP3 binding. The inability of gt(-/-) sperm to undergo a ZP3-induced acrosome reaction renders them physiologically inferior to wild-type sperm, as assayed by their relative inability to penetrate the egg coat and fertilize the oocyte in vitro. Thus, although ZP3 binding and subsequent induction of the acrosome reaction are dispensable for fertilization, they impart a physiological advantage to the fertilizing sperm. A second strain of mice was created that is characterized by a loss of of the long galactosyltransferase isoform responsible for ZP3-dependent signal transduction, but which maintains normal levels of Golgi galactosylation. Sperm from these mice show that the defective sperm-egg interactions in gt(-/-) mice are due directly to a loss of the long galactosyltransferase isoform from the sperm surface and are independent of the state of intracellular galactosylation during spermatogenesis.

Animals↗
PubMed1997

[Evaluation of different methods of detection and diagnosis for infectious pulmonary tuberculosis].

OBJECTIVE: To evaluate the compare the efficiency and benefit of fluoroscopy and direct sputum examination. METHOD: The suspected persons with pulmonary tuberculosis symptoms were enrolled to be examined with fluoroscopy, chest radiography, sputum smear and culture. RESULT: The diagnostic procedure used by World Bank-loaned Tuberculosis Control Project in China is based on fluoroscopy screening. The miss-detection rates of smear positive, culture positive and bacteriological positive pulmonary tuberculosis were 10.5%, 28.3% and 28.2% respectively. Its accuracy of diagnosis was lower than that of direct sputum smear examination and the cost was higher. CONCLUSION: Direct sputum smear examination seems to be the best diagnostic method for infectious pulmonary tuberculosis and suitable for application in rural areas.

Adolescent↗
PubMed1997

[Symptoms of depressive state in otolaryngology].

A psychiatric study was carried out to seek correct diagnosis and effective therapy for patients with various pain symptoms in ear, nose and throat area, and the unknown cause of pain and invalid treatment. There were 12 patients who coincided with the diagnostic criteria of depression. The therapeutic effect was satisfactory with antidepression medicine. It is suggested that the practicing ENT doctors should have some knowledge of psychiatry, understand the symptoms of depressive state, avoid misdiagnosis and offer correct management.

Adolescent↗
PubMed1997

[Comparison of 4 extraction methods of chemical constituents in medicinal tea sishen chaji].

Four extraction method for the medicinal tea Sishen Chaji, were compared with psoralen, schizandrin B and evodiamine taken as indexes. The result shows that the total contents of the three compounds decrease progressively in the following order: semi-bionic extraction, semi-bionic extraction by precipitation with alcohol, extraction with water, and extraction with water and precipitation with alcohol.

Cyclooctanes↗
PubMed1997

[Comparison of two extraction methods for maxingshigan decoction].

The semi-bionic extraction and the extraction with water, two methods for the Maxingshigan Decoction, were compared. The results show that the semi-bionic extraction is superior to the extraction with water in the yield of ephedrine, hydrocyanic acid, glycyrrhetinic acid, calcium ion and extract.

Calcium↗
PubMed1997

[In vitro expression of wild type and precore mutant woodchuck hepatitis virus].

Hepatitis B virus (HBV) precore 1896 and 1898 G-->A mutations are regarded as hot spots to study. Such mutants have been considered associating with molecular and biological changes of HBV and causing chronic hepatitis and severe forms of hepatitis, including fulminant hepatitis. Using oligonucleotide-directed mutagenesis, we have conducted the same point mutations in the precore gene of an infectious clone of woodchuck hepatitis virus (WHV-8). Transfection of mutant WHV DNA, 1896 mutant (WHV-M1) or both 1896 and 1898 mutants (WHV-M2) resulted in WHV replication. Southern blot and Northern blot tests showed that wild type and mutants both had similar DNA replication and transcription. It was concluded that the precore gene of the WHV genome is not essential for virus replication.

Animals↗
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

Diagnosis of primary liver cancer using lectin affinity chromatography of serum alkaline phosphatase.

Serum alkaline phosphatase (sALP) can be separated into unbound liver type (L-ALP) and bound bone type (B-ALP) by means of WGA affinity chromatography. The L-ALP from the sera of normal adults and various liver diseases was found to show different chromatographic behaviours on DSA affinity column with multiple peaks of ALP activity after the L-ALP was treated with neuraminidase to remove the terminal sialic acids on the sugar chain of L-ALP. The L-ALP from normal sera contained no bound activity on DSA, whereas that from acute or chronic hepatisis, liver cirrhosis and biliary obstruction had a significant amount of bound fractions with weak and intermediate affinity. The strongly bound fraction(s) was only present in the L-ALP serum from primary liver cancer (PLC) and the positive rate of its appearance was 100% in 38 cases of PLC, including 8 alpha-fetoprotein (AFP) negative cases. The WGA chromatography can be skipped and similar results are obtained. The percentage of the strongly bound fraction in serum L-ALP was not related to the level of either sALP activity or AFP, and the appearance of the strongly bound fraction is attributed to the structural difference of sugar chains in L-ALP. Therefore, this L-ALP fraction may be assumed as a new index in the diagnosis of PLC, and the different profiles of sALP or L-ALP on DSA chromatography may be used in the differential diagnosis of benign and malignant liver diseases.

Alkaline Phosphatase↗
PubMed1997

Aromatase in the normal breast and breast cancer.

Adipose tissue and muscle constitute the larger proportion of body mass, and therefore aromatization in these tissues is the major source of circulating estrogens in postmenopausal women. Although plasma estrogen concentrations are very low, levels in breast cancers from postmenopausal patients are reported to be 10-fold higher than in plasma and normal tissue. Whereas studies on aromatase activity in the tumor suggest that estrogen may be produced locally, the significance of this contribution has been questioned. Using immunocytochemistry (ICC) to an anti-aromatase antibody, a relatively strong immunoreaction was detected in tumor epithelial cells as well as in the terminal ductal lobular units (TDLUs) of the normal breast. Aromatase expression was detected in the cytoplasm of tumor epithelial cells and the surrounding stromal cells of over 50% of tumors in a series of 19 breast cancers. In situ hybridization (ISH) to aromatase mRNA confirmed the immunocytochemical result that the epithelial cells are the primary site of estrogen synthesis in the breast and breast cancers. In the 10 tumors which showed immunoreaction to aromatase, the average aromatase activity measured in cryosections was 286.5 +/- 18.6 fmol estrogen/mg protein/h (SE), whereas in nine tumors with weak aromatase immunoreaction, the enzyme activity was 154.7 +/- 19.3 fmol estrogen/mg protein/h (P < 0.05) (SE). The functional significance of tumor aromatase and locally produced estrogens on the growth of tumors was suggested by the correlation between aromatase activity and proliferating cell nuclear antigen (PCNA), a marker of cell proliferation (P < 0.005). Although intratumoral aromatase activity did not correlate with steroid receptors significantly, there was a trend for estrogen receptor (ER)-positive tumors to express aromatase. In addition, proliferation ([3H]-thymidine incorporation into DNA) during histoculture, was increased by both estradiol and testosterone in tumors with high aromatase activity. Our results suggest that some tumors synthesize sufficient estrogen to stimulate their proliferation. It may thus be important to inhibit tumor aromatase as well as to reduce circulating levels of estrogen for effective breast cancer treatment.

Aromatase↗
PubMed1997

A preliminary study on interruption of HBV transmission in uterus.

OBJECTIVE: The infection of Hepatitis B virus (HBV) in the uterus may occur in neonates born to HBV carrier mothers. The rates of intrauterine transmission in these neonates were 10%-16%, Recent studies on the methods of combined passive and active immunizations indicate an efficacy approaching 70%-90%, but intrauterine infection of HBV is the major cause of failure of vaccination to combat hepatitis B in neonates born to HBV carrier mothers. We studied the interruptive effect of HBV specific immunoglobulin (HBIG) before delivery in the prevention of intrauterine transmission of HBV. METHODS: Of 3632 pregnant women, two hundred and four were HBV carriers; they were randomly divided into an HBIG group and a control group. Each subject in the HBIG group received 200 IU of HBIG intramuscularly at 3, 2 and 1 month before delivery. The subjects in the control group did not receive any specific treatment. Blood tests were conducted for all the subjects and their neonates after birth. Blood specimens were tested for HBsAg and HBeAg by enzyme immunoassay (Abbott Kits). RESULTS: The results showed that the rates of intrauterine transmission in the two groups were 5.7% and 14.7% respectively (X2 = 4.58 P < 0.05). No significant differences were observed for the positive rates of HBsAg and HBeAg between the two groups after delivery, but titer of HBsAg was reduced significantly in the HBIG group (t = 4.82, P < 0.01). CONCLUSIONS: Our study suggests that HBV infection in the uterus may be interrupted using multiple HBIG intramuscularly before delivery without any side effects.

Adult↗
PubMed1996

Nucleoside-diphosphate kinase-mediated signal transduction via histidyl-aspartyl phosphorelay systems in Escherichia coli.

Nucleoside-diphosphate kinase (NDP kinase), a key enzyme in nucleotide metabolism, is also known to be involved in growth and developmental control and tumor metastasis suppression. Interestingly, we find that coexpression of NDP kinase with Taz1, a Tar/EnvZ chimera, in the absence of its native signal, can activate a porin gene ompC-lacZ expression in Escherichia coli. Further studies show that NDP kinase can act as a protein kinase to phosphorylate histidine protein kinases such as EnvZ and CheA which are members of the His-Asp phosphorelay signal transduction systems in E. coli. Instead of ATP, the exclusive phosphodonor for histidine kinases, GTP can be utilized in vitro in the presence of NDP kinase to phosphorylate EnvZ and CheA, which then transfer the phosphoryl group to OmpR and CheY, the respective response regulators. The direct involvement of GTP for the phosphorylation of EnvZ through NDP kinase was further demonstrated by the use of a mutant EnvZ, which lost ability to be autophosphorylated with ATP. Phospho-OmpR thus formed can bind specifically to an ompF promoter sequence. These results suggest that NDP kinase may play a physiological role in signal transduction.

Aspartic Acid↗
PubMed1996

Reciprocal regulation of delta 1-pyrroline-5-carboxylate synthetase and proline dehydrogenase genes controls proline levels during and after osmotic stress in plants.

Plants generally accumulate free proline under osmotic stress conditions. Upon removal of the osmotic stress, the proline levels return to normal. In order to understand the mechanisms involved in regulating the levels of proline, we cloned and characterized a proline dehydrogenase (PDH) cDNA from Arabidopsis thaliana (AtPDH). The 1745 bp cDNA contains a major open reading frame encoding a peptide of 499 amino acids. The deduced amino acid sequence has high homology with both Saccharomyces cerevisiae and Drosophila melanogaster proline oxidases and contains a putative mitochondrial targeting sequence. When expressed in yeast, the AtPDH cDNA complemented a yeast put1 mutation and exhibited proline oxidase activity. We also determined the free proline contents and the delta 1-pyrroline-5-carboxylate synthetase (P5CS) and PDH mRNA levels under different osmotic stress and recovery conditions. The results demonstrated that the removal of free proline during the recovery from salinity or dehydration stress involves an induction of the PDH gene while the activity of P5CS declines. The reciprocal regulation of P5CS and PDH genes appears to be a key mechanism in the control of the levels of proline during and after osmotic stress. The PDH gene was also significantly induced by exogenously applied proline. The induction of PDH by proline, however, was inhibited by salt stress.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1996

Calpain inhibitors and serine protease inhibitors can produce apoptosis in HL-60 cells.

Recent investigations indicate that proteolysis is an important event in generation of the apoptosis phenotype. Although various proteases have been suggested to be candidates for this proteolysis, the results from different laboratories are inconsistent. In the present studies, HL-60 cells were treated with cycloheximide to investigate proteases involved in apoptosis. The calpain inhibitors benzyloxycarbonyl-Leu-Leu-Tyr diazomethylketone and acetyl-Leu-Leu-Nle aldehyde were not capable of preventing apoptosis induced by cycloheximide. In the absence of cycloheximide, these two inhibitors could initiate apoptosis in HL-60 cells. The thiol protease inhibitor benzyloxycarbonyl-Leu-Val-Gly diazomethylketone neither prevented nor produced apoptosis. The serine protease inhibitors 3,4-dichloroisocoumarin (DCI) and tosyl-Phe chloromethylketone (TPCK) also induced apoptosis in the absence of cycloheximide. On the other hand, the latter two inhibitors decreased cycloheximide-induced apoptosis, assessed either by cell morphologic changes or DNA ladder generation. Benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone and iodoacetamide, inactivators of interleukin 1beta-converting enzyme (ICE)-like proteases, did not produce apoptosis and inhibited the induction of apoptosis by cycloheximide, calpain inhibitors, or serine protease inhibitors. These results are consistent with the ICE-like proteases having a central role in proteolysis during apoptosis, while calpain-like proteases and the serine proteases sensitive to DCI or TPCK are not required for generation of the apoptosis phenotype in HL-60 cells.

Apoptosis↗
PubMed1996

Isolation of a Chinese hamster ovary cell clone possessing decreased mu-calpain content and a reduced proliferative growth rate.

A Chinese hamster ovary cell line (CHOp) was cultured in the presence of benzyloxycarbonyl-Leu-Leu-Tyr diazomethyl ketone (ZLLY-CHN2), to select for resistance to this cell-permeant calpain inhibitor. A clone isolated after several courses of exposure (SHI cells) demonstrated decreased sensitivity to ZLLY-CHN2 toxicity and a decreased growth rate. SHI cells also possessed less mu-calpain isozyme relative to CHOp cells, as determined by activity measurement or by protein immunoblotting. Activities of m-calpain, calpastatin, cathepsin B, cathepsin L, and glycogen phosphorylase were not altered. SHI mu-calpain was partially purified by sequential chromatography on Bio-Gel A-1.5m and DEAE-Sepharose. Its chromatographic behavior in either system was the same as for CHOp mu-calpain. Further studies with the partially purified SHI and CHOp mu-calpain fractions failed to distinguish any difference in Ca2+ requirement or in sensitivity to inhibition by calpastatin or ZLLY-CHN2 for these enzymes. These experiments suggest that SHI cells underproduce a form of mu-calpain which is very similar to, if not identical with, CHOp mu-calpain. SHI cells displayed a population doubling time of 29 h compared with 19 h for CHOp cells. The decreased growth rate of SHI cells was the result of a prolonged G1 phase. Introduction of purified human mu-calpain into SHI cells by electroporation transiently restored the growth rate and also increased toxicity associated with exposure to ZLLY-CHN2. SHI cells should be a valuable model in further studies to delineate the function of mu-calpain in cell proliferative growth.

Animals↗
PubMed1996

Pbx-1 Hox heterodimers bind DNA on inseparable half-sites that permit intrinsic DNA binding specificity of the Hox partner at nucleotides 3' to a TAAT motif.

Heterodimers between the Pbx/Exd and Hox/HOM-C classes of homeodomain proteins bind regulatory elements in tissue-specific and developmentally regulated genes. In this work, we characterize the half-site bound by both Pbx1 and Hox proteins on a prototypic element (TGATTAAT) and determine how the orientation of the Hox protein contributes to the DNA binding specificity of Pbx-Hox heterodimers. We demonstrate that the Hox protein binds the 3' TAAT sequence as its recognition core and exhibits sequence-specific binding at positions 3' to the TAAT core. Unfavored sequences at this position, such as two cytosines, abrogate binding to the element. The upstream Pbx1 core sequence, TGAT, must immediately juxtapose the Hox core. This geometry maintains the preference of Hox/HOM-C proteins for a T base at position -1, as T represents the fourth position of the Pbx1 core, and suggests that this T base is bound by both Pbx1 and Hox proteins, Pbx1 binding in the major grove and the Hox protein binding in the minor grove. Pbx1 also exhibits base selectivity 5' to its TGAT recognition sequence.

Base Sequence↗