[Acute phosgene poisoning: therapeutic effect of 156 cases].
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Aerosols↗
Biomedical subjects
J Zhu
Publications and source records attributed to J Zhu.
The chromatin structure of the human epsilon globin gene: nuclease hypersensitive sites correlate with multiple initiation sites of transcription.
We have mapped sites in chromatin flanking the epsilon-globin gene in the K562 cell which are hypersensitive to digestion with DNAseI, micrococcal nuclease and S1 nuclease. Many of those in the 5' flanking region correspond to minor upstream transcriptional starts. However, one prominent site occurs upstream of the boundary of transcription; it maps to a region with an unusual DNA sequence. In baby hamster kidney cells stably transformed with recombinant DNA containing the human epsilon-globin gene and in Cos 7 cells transiently transfected with DNA containing the epsilon-globin gene, hypersensitive sites can be demonstrated.
Animals↗
Intragenic complementation by the nifJ-coded protein of Klebsiella pneumoniae.
A single mutation, nifC1005 (Jin et al. Sci. Sin. 23:108-118, 1980), located between nifH and nifJ in the nif cluster of Klebsiella pneumoniae, genetically complemented mutations in each of the 17 known nif genes. This suggested that the mutation is located in a new nif gene. We showed by complementation analyses that only 3 of 12 nifJ mutations tested were complemented by nifC1005. Nitrogenase activity in cell extracts of the mutant with nifC1005 as well as NifJ- mutants was stimulated by the addition of the iron-molybdenum cofactor or nitrogenase component I. The molecular weight of the native NifJ protein is approximately 257,000--a dimer of identical subunits. Some nifC-/nifJ- or nifJ-/nifJ- merodiploids produced active but unstable nifJ proteins. Fine-structure mapping placed the nifC1005 allele within the nifJ gene bounded on both sides by well-characterized nifJ mutations. This indicates that the nifC1005 does not define a separate gene from nifJ. The data are consistent with the occurrence of intragenic complementation between two defective nifJ polypeptides. This explains the isolated examples of genetic complementation between the nifC1005 mutation and certain nifJ mutations.
Bacterial Proteins↗
Regulation of nitrogen fixation in Klebsiella pneumoniae: isolation and characterization of strains with nif-lac fusions.
Strains with lac fused to each of the seven nif operons were isolated by two different methods. Repressing conditions prevented expression of all nif operons, whereas derepressing conditions led to the expression of all nif operons. No differences in Nif regulation were observed between Escherichia coli and Klebsiella pneumoniae with the same nif-lac fusions. Most derivatives of nif-lac fusion strains selected on lactose and NH4+ contained nif operator mutations. Some derivative contained deletions, which establishes that the direction of transcription of all seven nif operons is toward his
DNA, Recombinant↗
Temperature sensitivity of the regulation of nitrogenase synthesis by Klebsiella pneumoniae.
Temperature sensitivity of the regulatory protein coded by nifA prevents the organism from utilizing N2 at 37 degrees C. The purpling of 6-cyanopurine, a function of nifA expression, also is thermolabile.
Gene Expression Regulation↗
SPIDER and WEB: processing and visualization of images in 3D electron microscopy and related fields.
The SPIDER system has evolved into a comprehensive tool set for image processing, making use of modern graphics interfacing in the VMS and UNIX environment. SPIDER and WEB handle the complementary tasks of batch processing and visualization of the results. The emphasis of the SPIDER system remains in the area of single particle averaging and reconstruction, although a variety of other application areas have been added. Novel features are a suite of operations relating to the determination, modeling, and correction of the contrast transfer function and the availability of the entire documentation in hypertext format.
Animals↗
Improved biosensor for glucose based on glucose oxidase-immobilized silk fibroin membrane.
Based on glucose oxidase-immobilized silk fibroin membrane and oxygen electrode, the authors have developed an amperometric glucose sensor in flow-injection analysis. After the sensor was improved by the configuration of oxygen electrode and a temperature control system was added to the electrode body, its sensitivity, analytical precision, and stability were enhanced greatly. The authors first introduced a tailing inhibitor-ion pair reagent into a buffer system in the biosensor so as to eliminate all interference from hemacyte, macromolecules, and small mol wt charged species besides electroactive specie ascorbate in complex matrices. A considerably serious tailing of the biosamples, such as whole blood, plasma, serum, or urine on the sensor, based on enzyme electrode, entirely disappeared, their response times were shortened, and base lines became more smooth and stable. The glucose sensor has a broad range of linear response for glucose (up to 25.0 mmol/L) and a good correlation (gamma = 0.999) under conditions of control temperature 32.0 degrees C and 1.6 mL/min 0.02 mol/L phosphate buffer containing 0.5% tailing inhibitor (v/v). Recoveries of glucose in these biosamples are within the range of 93.71-105.88%, and its repeatabilities for determining glucose, repeated 100 times, human blood dilution 125 times, and serum 128 times, are 1.81, 2.48, and 2.91% (RSD), respectively. The correlation analysis for 200 serum samples showed that the correlation (gamma) is 0.9934 between the glucose sensor and Worthington method for determining serum glucose used conventionally in a hospital laboratory. Moreover, the enzyme membrane used in the biosensor can be stored for a long time (over 2 yr) and measured repeatedly over 1000 times for biosamples. The glucose sensor is capable of detecting over 60 biosamples/hr.
Animals↗
Effect of monoamine reuptake inhibiting antidepressants on major histocompatibility complex expression on macrophages in normal rats and rats with experimental allergic neuritis (EAN).
This study examined the modulation of IFN-gamma induced MHC class I and II expression on normal Lewis rats and rats with EAN peritoneal macrophages cultured in the absence or presence of 10(-4)-10(-8) M of the 5-HT reuptake inhibiting antidepressants zimeldine, and its metabolites norzimeldine and cpp200 oxalate as well as the antidepressants clomipramine and imipramine, in addition amitriptyline, nortriptyline and maprotiline in EAN rats. In normal rats, MHC class I expression was suppressed by the antidepressants zimeldine, norzimeldine and cpp200 oxalate at concentrations up to 10(-5) M. At concentrations between 10(-6) to 10(-8) M, the same drugs significantly enhanced MHC class expression. Clomipramine at 10(-8) M and imipramine at 10(-6)-10(-7) M enhanced MHC class I expression, while the MHC class II expression was not significantly influenced by concentrations < or = 10(-5) M of these two drugs. In EAN rats, MHC class I expression was enhanced by zimeldine, cpp200, imipramine, and nortriptyline at 10(-5)-10(-8) M, amitriptyline at 10(-5)-10(-7) M as well as by norzimeldine and clomipramine at 10(-6) M-10(-8) M. However, maprotiline at 10(-4)-10(-6) M suppressed class I expression in the presence of 0.5 U/ml and 1.0 U/ml of IFN-gamma. MHC class II expression was suppressed by cpp200 and clomipramine at 10(-4)-10(-5) M in presence of 0.5 U/ml of IFN-gamma. At concentrations < 10(-5) M most tested drugs significantly enhanced IFN-gamma induced MHC class II expression. Compared to the results in normal rats, drug effects on EAN macrophages were more pronounced and reached higher levels of significance. The 5-HT reuptake inhibiting antidepressants also exerted a modulatory effect on MHC class I and II in EAN rat macrophages even in the absence of IFN-gamma. The modulatory effect of antidepressant drugs on IFN-gamma induced MHC class I and II expression may contribute to their influence on demyelinating autoimmune diseases, and may have implications for their clinical use.
Amitriptyline↗
The thickness of shock layers in liquid chromatography.
At high concentrations, one boundary (the front if the isotherm is convex upward) of the elution band of a single component becomes very steep. Similarly, in frontal analysis, the same boundary is self-sharpening. These steep boundaries are called shock layers. They result from the steady-state equilibrium between a nonlinear thermodynamics of phase equilibrium on the one hand, which tends to create a concentration discontinuity, and axial dispersion and a finite rate of mass transfer on the other hand, which tend to relax the concentration gradient. We show that the width of experimental breakthrough curves recorded in frontal analysis agrees well with the prediction of the shock layer theory of Rhee and Amundson in the high concentration range. It is a function of the coefficients of the column HETP equation and the height of the concentration step and is independent of the column length, after the steady state is achieved. In the low concentration range, a discrepancy is observed when the column length is short and the migration distance is insufficient to achieve constant pattern behavior.
Adsorption↗
In silico techniques for the study and prediction of xenobiotic metabolism: a review.
Knowledge about metabolism is very important to understand the health risks posed by chemicals. The biochemical process of metabolism causes activation, inactivation, toxification, detoxification as well as changes in the physicochemical properties of a chemical. The long time consumption and high costs associated with animal tests and the challenges faced by traditional quantitative structure-activity relationship (QSAR) models in dealing with situations wherein parent chemical structures are less relevant to the ultimate effects have led to the development of in silico techniques for the prediction of xenobiotic metabolism. The strengths and limitations of some of the most commonly used in silico expert systems, and their application in studying metabolism of xenobiotic chemicals, have been reviewed. The in silico metabolism simulators possessed several distinguishing features imparted in part by the nature of knowledge rules (algorithms) encoded within them and in part by the integration of QSAR libraries and computational engines.
Algorithms↗
Detection of 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP)-DNA adducts in human pancreatic tissues.
Recent epidemiological investigations have observed an association between the consumption of grilled or barbecued meat and an increased risk of pancreatic cancer, suggesting that dietary exposure to heterocyclic aromatic amines (HCA) may contribute to the development of this disease. 2-Amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP) is the most abundant HCA found in well-done and grilled meats. To determine whether HCA-induced DNA damage is present in the human pancreas, immunohistochemistry and computer-assisted image analysis were used to measure PhIP-DNA adducts in 54 normal pancreatic tissues (N) from persons without pancreatic cancer and in 38 normal adjacent pancreatic tissues (A) and in 39 cancer tissues (T) from 68 patients with pancreatic adenocarcinoma. PhIP-DNA adducts were detected in 53 N, 34 A and 39 T samples. Mean values (+/-SD) of the absorbency for PhIP staining were 0.22+/-0.04, 0.24+/-0.04, and 0.24+/-0.03 for N, A, and T samples, respectively (p=0.004). Using the median absorbency (0.21) of the samples from normal controls as the cut-off, 71% of A and 77% of T tissues, compared with 48% of N tissues, were distributed in the higher range (p=0.009). The odds ratio of pancreatic cancer was 3.4 (95% confidence interval 1.5-7.5, p=0.002) for individuals with a higher level of PhIP-DNA adducts. This is the first report of the detection of PhIP-DNA adducts in human pancreatic tissue samples obtained from patients with unknown exposure to HCA. Although limited by the small sample size, these preliminary results suggest that PhIP exposure may contribute to human pancreatic cancer development.
Adenocarcinoma↗
Fatal occupational injuries in the construction industry of a new development area in east China, 1991 to 1997.
Two hundred thirty-five work-related deaths occurred in the construction industry in a new economic development area in eastern China between 1991 and 1997. These fatalities represented 55% of all occupational deaths. The average annual mortality rate was 51.5 per 100,000 construction workers. Falls were the leading cause of death (46.4%). Falls, collisions, struck by/against something, electrocutions, and excavation cave-ins were the main fatality antecedents, accounting for nearly 93.6% of all fatalities. The most common antecedents for incidents with multiple fatalities were falls, crane-related events, poisoning, and fire. These categories of antecedents were similar to those encountered in the construction industry in the United States. These data suggest that organizations need to focus on these event types when planning their prevention activities. Moreover, improved surveillance systems including computerized databases with narrative descriptions of injury events, antecedent factors, and person-time at-risk data are needed to target interventions more precisely.
Accidents, Occupational↗
SCPD: a promoter database of the yeast Saccharomyces cerevisiae.
MOTIVATION: In order to facilitate a systematic study of the promoters and transcriptionally regulatory cis-elements of the yeast Saccharomyces cerevisiae on a genomic scale, we have developed a comprehensive yeast-specific promoter database, SCPD. RESULTS: Currently SCPD contains 580 experimentally mapped transcription factor (TF) binding sites and 425 transcriptional start sites (TSS) as its primary data entries. It also contains relevant binding affinity and expression data where available. In addition to mechanisms for promoter information (including sequence) retrieval and a data submission form, SCPD also provides some simple but useful tools for promoter sequence analysis. AVAILABILITY: SCPD can be accessed from the URL http://cgsigma.cshl.org/jian. The database is continually updated.
Binding Sites↗
A model of the translational apparatus based on a three-dimensional reconstruction of the Escherichia coli ribosome.
The morphology of the Escherichia coli ribosome, i.e., its shape at moderate to low (20-40 A (1 A = 0.1 nm)) resolution, provides important constraints in modeling both the folding of ribosomal RNA and the translational process. A new reconstruction, obtained by low-dose cryoelectron microscopy and image processing of single ribosomes, contains clues to the way in which the ribosome interacts with the key functional ligands: the mRNA and the A- and P-site tRNAs. It also suggests possible pathways of the nascent polypeptide chain. From an interpretation of these clues in the light of existing knowledge, a plausible model for the locations and interactions of key components of protein synthesis is suggested.
Escherichia coli↗
Decreased neointimal thickening after arterial wall injury in inducible nitric oxide synthase knockout mice.
Mechanical injury in vivo results in the expression of the inducible form of nitric oxide synthase (iNOS) in vascular smooth muscle cells. However, the role of iNOS in modulating neointima formation after arterial wall injury is not clear. To determine whether the induction of iNOS gene expression promotes or attenuates the neointimal response to injury, we used a murine model of perivascular injury induced by placing a periadventitial collar around the carotid arteries in both wild-type and iNOS knockout mice (iNOS-KO mice). Periadventitial injury induced iNOS expression in the wild-type but not the iNOS-KO mice. Neointimal area and the intima/media ratio were significantly less in the iNOS-KO mice compared with the wild-type mice at 21 days. Injury-induced proliferation of medial cells and vascular cell adhesion molecule-1 expression were also attenuated in iNOS-KO mice compared with wild-type mice. The induction of iNOS and the activation of the nuclear factor-kappaB-mediated pathway were also demonstrated in an in vitro injury model. We conclude that mechanical injury in vivo and in vitro induces iNOS expression and that lack of iNOS expression attenuates neointima formation after perivascular arterial injury. Taken together, these findings suggest that iNOS expression after vascular injury may promote neointima formation.
Animals↗
Involvement of opioid peptides of the preoptic area during electroacupuncture analgesia.
The present work was to study the roles of opioid peptides in the preoptic area on electroacupuncture analgesia (EA), and the effects of opioid peptides on noradrenaline (NA) release in the preoptic area during EA. It was found that the pain threshold and the level of [Leu5] enkephalin (L-EK) or beta-endorphin (beta-EP) release in the perfusate were increased during EA, but the NA release from the preoptic area was decreased. Naloxone (15 microM) perfusion significantly reversed the increased pain threshold and the decreased NA release induced by acupuncture. The reversal of pain threshold and the decreased NA release induced by acupuncture. The reversal of pain threshold and NA release by naloxone was dose-dependent. Multimicropipettes and microiontophoresis were also used to study the effect of acupuncture. The inhibition of nociceptive neuronal discharges produced by electroacupuncture was closely related to the etorphine-sensitive neurons, and reversed by microiontophoretic application of naloxone. The results suggest that the inhibitory effect induced by electroacupuncture may be mediated by opioid peptides in the preoptic area.
Acupuncture Analgesia↗
Kinetic differences in intestinal and systemic interferon-gamma and antigen-specific antibodies in chickens experimentally infected with Eimeria maxima.
Kinetic differences between systemic vs. intestinal and humoral vs. cellular immune responses were elucidated in chickens experimentally infected with Eimeria maxima by comparing interferon-gamma (IFN-gamma) and parasite-specific antibody levels in the intestine and serum during the course of infection. The level of serum IFN-gamma correlated significantly with fecal oocyst shedding (r2 = 0.97), thereby establishing the importance of cell-mediated immunity in coccidia infection. Moreover, intestinal IFN-gamma levels increased sooner than those in sera (4 vs. 6 days postinfection) and both were observed prior to the appearance of parasite-specific antibodies (8-10 days postinfection), again indicating the importance of intestinal cellular immunity in coccidiosis. Although immunoglobulin (Ig)G, IgA, and IgM isotypes of the antigen-specific antibody response increased significantly in both the intestine and serum after E. maxima infection, intestinal IgA-specific antibodies showed the most dramatic increase. However, the relevance of this observation in the context of primary Eimeria infection is unclear because the coccidia parasites have reached the final stages of their life cycle by this time. These results thus demonstrate the importance of T-cell immune responses against coccidia, characterized by local IFN-gamma secretion in the intestine, in mediating host protective immune response to coccidia.
Animals↗
Effect of subarachnoid morphine on the incidence of spinal headache.
BACKGROUND AND OBJECTIVES: The addition of fentanyl to hyperbaric local anesthetics has been shown to reduce the incidence of post dural puncture headache in the obstetric patient. This study was undertaken to evaluate the effects of subarachnoid morphine on the incidence of headache. METHODS: Eighty-two healthy patients undergoing cesarean delivery with spinal anesthesia were studied. All patients were hydrated with 1500 ml lactated Ringer's solution. Patients were randomly assigned to receive, in a double-blind fashion, 0.2 mg of either morphine (Group 1, n = 40) or saline (Group 2, n = 42) in 0.2 ml volume mixed with 0.75% bupivacaine in 8.25% dextrose plus 0.2 ml 1:1000 epinephrine. Spinal anesthesia was induced using a 25-gauge spinal needle at L3-4 interspace with the bevel, in most cases, parallel to the dural fibers. Patients were followed for three days to evaluate the incidence and severity of headache using a four-category rank scale (none, mild, moderate, severe). Data were analyzed for statistical significance using Student's t-test or chi-square test as appropriate. A p value less than 0.05 was considered significant. Results. The incidence of post dural puncture headache did not differ significantly between groups. Eight patients in Group 1 versus nine patients in Group 2 developed headache (p greater than 0.05). Similarly, the use of blood patch or intravenous caffeine sodium benzoate to treat the headache did not differ significantly between groups. CONCLUSION: It is concluded from our study that subarachnoid morphine did not decrease the incidence of post dural puncture headache in the obstetric patient.
Adult↗