Search PubMed⌕ Search

Biomedical subjects

Z Zhu

Publications and source records attributed to Z Zhu.

At least 271 records · Page 15Linked to original sources

[Induction of hematopoietic cell apoptosis by the serum from immune-mediated aplastic anemia mice].

OBJECTIVE: To explore the mechanism of the impairment of hematopoietic stem/progenitor cells in aplastic anemia(AA) mice. METHODS: The hematopoietic cells from normal mice bone marrow were incubated with serum from AA mice in the presence of recombinant GM-CSF and IL-3. Parallel controls, i.e. hematopoietic cells from normal mice with or without serum of normal mice, were conducted. At different time, samples were collected and detected by flow cytometry (FACS), transmission electron microscopy (TEM) and gel electrophoresis. RESULTS: In the 16 post hour-culture of the experimental group mice: (i) The percentages of apoptotic cells were increased. (ii) Hematopoietic cells showed nuclear condensation, margination and blebbing under TEM. (iii) Agarose gel electrophoresis of DNA from the 13,000x g supernatant showed a ladder pattern. The percentage of DNA fragmentation measured by diphenylamine reaction was also increased and (iv) ZnSO4, cycloheximide and actinomycin D could partially suppress the induction of DNA fragmentation and delay the ocurrence of apoptosis. CONCLUSION: Apoptosis occurs in hematopoietic cells when incubated with serum from immune-mediated AA mice.

Anemia, Aplastic↗

[Leu 72 Pro mutation in the NADH-cytochrome b5 reductase gene found in a Chinese hereditary methemoglobinemia patient].

OBJECTIVE: To characterize the mutation in NADH-cytochrome b5 reductase gene in a Chinese hereditary methemoglobinemia patient, and elucidate the molecular basis of the disease. METHODS: B5R gene from a propositus was analyzed by sequencing the RT-PCR products as well as cDNA clones; and the results were further confirmed by restriction enzyme analysis of the genomic DNA fragments. RESULTS: A novel mutation was found at codon 72 of b5R gene from the propositus. CONCLUSION: Replacement of Leu with Pro at codon 72 of b5R gene is the molecular basis of the propositus; and the mutant allele located in 5' part of b5R gene mainly cause hereditary methemoglobinemia type I.

Child, Preschool↗

[Determination of oleanolic acid and total saponins in Aralia L].

OBJECTIVE: To search for higher contents of olenolic acid and saponins in Aralia for medicinal use. METHOD: A HPLC method was developed for the determination of olenolic acid in Aralia. An YWG C-18 column was used and the mobile phase was methanol-water(90:10). The detection wavelength was UV 210 nm. The total saponins were determined by colorimetry. RESULT: Olenolic acid in root or stems of 13 species and total saponins in whole roots and root barks of 14 species of Aralia were determined. The contents of olenolic acid and total saponins in woody Aralia were higher than those in herbaceous. CONCLUSION: The contents of olenolic acid in A. decaisneana, A. elata, A. chinocaulis, A. chinensis and A. chinensis var. dasyphylloides are higher than those in other species. Furthermore, A. decaisneana and A. elata are rich in wild resources and thus of importance to the development and utilization of wild plants containing olenolic acid.

Aralia↗

[Determination of diterpenoic acid, triterpenoids and tritersaponins in Aralia by RP-HPLC].

In this paper, an accurate RP-HPLC method for the determination of oleanolic acid 28-O-beta-D-glucopyranoside (I), oleanolic acid 3-O-alpha-L-arabinopyranoside (II), 3 beta-hydroxy-oleana-11, 13(18)-dien-28-oic acid (III), (ent)-pimara-8(14), 15-dien-19-oic acid (IV), oleanolic acid (V) and 3-ox-oleana-12-en-28-oic acid (VI) in 11 species of Aralia Linn. was described. The analytical column used was Supelco SIL-LC-18. The mobile phase was MeOH-1%HOAc-THF (500:110:1, pH 3.4). The flow rate was 1.2 ml.min-1. The detection wavelength was 205 nm. The linear ranges of I-VI were 0.135-2.160, 0.163-2.610, 0.123-1.962, 0.068-1.080, 0.135-2.160 and 0.248-2.646 micrograms, respectively. The recoveries of I-VI were from 86.88% to 93.31%. Detailed comparison of the diterpenoic acid, triterpenoids and tritersaponins for the group of herbal with those of woody the content of diterpenoic acid in herbal is higher than that of in woody. It showed that the diterponic acid is the specific constituent in the group of herbal, which is the difference to woody. This conclusion provides the evidence of the chemical classification for dividing the groups of herbal and woody into two distinct subgenus.

Aralia↗

[Studies on the experimental transmission of Rattus-borne Hantavirus by Ornithonyssus bacoti].

AIM: To demonstrate the role of rat mite (Ornithonyssus bacoti) in the transmission of Rattus-borne hemorrhagic fever with renal syndrome (HFRS). METHODS: In the transmission experiments, about 100 O. bacoti per pool were isolated and placed in a jar, unfed for 4 d at 23 +/- 1 degrees C. Suckling Wistar rats inoculated with Hantavirus strain Z45 or Seoul virus strain UR were placed in each jar for free attack by the mites for 12 hours. After 14 d the normal suckling Wistar rats were bitten by the mites. Fifteen days later, the lung tissues and sera of the infected rats were collected and detected for Hantaviral antigen by indirect fluorescent antibody technique (IFAT). For demonstration of the infection of O. bacti with Rattus-borne Hantavirus PCR technique was applied to detect Rattus-borne Hantaviral RNA. RESULTS: Sukling Wistar rats inoculted Hantavirus strain Z45 or Seoul virus strain UR were bitten by O. bacoti and then these mites were fed on 4 and 5 of normal suckling rats in each jar, respectively. The antigens of Hantavirus strain Z45 were positive in all the lungs of the normal rats bitten by the mites, the sera titers of the rats were from 1:10 to 1:40. The antigens were positive in 3 of the 4 rats, the sera titers were from 1:20 to 1:40. Both of the viruses could be maintained in O. bacoti for 22 days. The blocking test showed when 1:30 Hantavirus immunosera were exposed to the lung samples and then reacted with the sera from the patients with HFRS, all the specific fluorescence reactions of the samples were blocked, whereas the control group including the normal rat lung tissues and sera were all negative (Fig. 1). CONCLUSION: O. bacoti might play a role as the vector of HFRS and a reservoir host as well.

Animals↗

[Triterpenoids from the root bark of Aralia subcapitata].

OBJECTIVE: To investigate the chemical constituents of Aralia subcapitata. METHOD: The methanol extract of A. subcapitata was separated by repeated column chromatography, and the compounds were identified on the basis of spectroscopic analysis(IR, EI-MS, 1HNMR and 13CNMR) and physicochemical properties. RESULT: Four compounds were isolated from the root bark of A. subcapitata. Their structures were identified as 3 beta-hydroxy-oleana-11, 13(18)-dien-28-oic acid(I), 3-oxo-oleana-12-en-28-oic acid (II), oleanolic acid(III) and daucosterol(IV). CONCLUSION: All these compounds were isolated from this plant for the first time. Among them, compounds I and II were obtained for the first time from Aralia.

Aralia↗

[Determination of zinc, copper, iron and manganese contents in hair for MPA patients and healthy men].

In this paper the contents of zinc, copper, iron and manganese in hair for MPA patients and 38 hair-healthy men have been determined by FAAS. The results show that the hair zinc and manganese levels in MPA patients are significantly lower than that in hair-healthy men. The hair copper level in MPA patients is significantly higher than that in hair-healthy men. There are statistic difference (P < 0.05) in hair zinc, copper and menganese levels among two groups. There is no statistic difference (P > 0.05) in the iron level among the two gopups. This paper provides useful material for the research of the cause and treatment of the MPA.

Alopecia↗

Sodium, potassium, two chloride cotransport in corneal endothelium: characterization and possible role in volume regulation and fluid transport.

PURPOSE: To search for membrane transporter proteins that could contribute to volume regulation and fluid transport by corneal endothelium. As an initial step, the authors have focused on Na+-K+-2Cl- cotransporters. METHODS: Bovine corneal endothelial cells were cultured to confluence. 86Rubidium was used as a tracer for K+ uptake determinations; uptake values were normalized per milligram of cell protein. RESULTS: Three components of K+ uptake were characterized: ouabain (1 mM) sensitive, bumetanide (0.1 mM) sensitive, and ouabain-bumetanide insensitive. Both the ouabain-sensitive and bumetanide-sensitive components increased in the presence of 26.2 mM HCO3-; 0.5 mM 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid abolished this increase. The bumetanide-sensitive component was completely inhibited in the absence of Na+ or Cl-. This component was increased 33% by a 33% hypertonic solution and was decreased 38% by a 33% hypotonic solution. The protein kinase C activator phorbol 12-myristate 13-acetate decreased the activity of the cotransporter, whereas forskolin, in the presence of isobutylmethylxanthine, decreased it. Calyculin A (100 nM), an inhibitor of phosphatases 1 and 2a, produced a large (97%) activation of this component. CONCLUSIONS: These results provided for the first time conclusive evidence for the presence of a Na+-K+-2Cl- cotransporter in corneal endothelium and of its possible involvement in volume-regulatory processes in these cells. Given the uptake values reported here, such cotransporter could contribute significantly to electrolyte transport and hence to fluid transport across this preparation.

1-Methyl-3-isobutylxanthine↗

Molecular characterization of human and rat RGS 9L, a novel splice variant enriched in dopamine target regions, and chromosomal localization of the RGS 9 gene.

A novel splice variant of RGS 9 was isolated from a rat hypothalamus, human retina, and a human kidney (Wilm's) tumor. This variant, termed RGS 9L, differs from the retinal form (termed RGS 9S) identified previously in that it contains a 211- (rat) or 205- (human) amino acid proline-rich domain on the carboxyl terminus. The pattern of RGS 9 mRNA splicing was tissue specific, with striatum, hypothalamus- and nucleus accumbens expressing RGS 9L, whereas retina and pineal expressed RGS 9S almost exclusively. This pattern of mRNA splicing seemed to be highly conserved between human and rodents, suggesting cell-specific differences in the function of these variants. Transient expression of RGS 9L augmented basal and beta-adrenergic receptor-stimulated adenylyl cyclase activity while suppressing dopamine D2 receptor-mediated inhibition. Furthermore, RGS 9L expression greatly accelerated the decay of dopamine D2 receptor-induced GIRK current. These results indicate RGS 9L inhibits heterotrimeric Gi function in vivo, probably by acting as a GTPase-activating protein. The human RGS 9 gene was localized to chromosome 17 q23-24 by radiation hybrid and fluorescent in situ hybridization analyses. The RGS 9 gene is within a previously defined locus for retinitis pigmentosa (RP 17), a disease that has been linked to genes in the rhodopsin/transducin/cGMP signaling pathway.

Alternative Splicing↗

Influence of piperacillin-tazobactam on pharmacokinetics of gentamicin given once daily.

The effect of piperacillin-tazobactam on the pharmacokinetics of gentamicin given once daily was studied. Healthy adult volunteers each received four drug regimens in randomized order: gentamicin 7 mg/kg i.v. once daily (1) by itself, (2) with piperacillin 4 g and tazobactam 0.5 g (both as the sodium salt) every six hours i.v., (3) with piperacillin 4 g and tazobactam 0.5 g i.v. every eight hours, and (4) with piperacillin 8 g and tazobactam 1 g by continuous i.v. infusion over 24 hours. All the gentamicin doses were infused over 30 minutes two hours after piperacillin-tazobactam. Blood samples were drawn before and at the end of each gentamicin infusion and at intervals up to 12 hours after the start of each gentamicin infusion. Samples were assayed for gentamicin concentration by an enzyme-multiplied immunoassay technique and for piperacillin and tazobactam concentrations by high-performance liquid chromatography. Six women and four men completed all four drug regimens. For the gentamicin-alone regimen, the mean +/- S.D. area under the concentration-versus-time curve was 78.06 +/- 10.28 micrograms/mL.hr, the mean +/- S.D. peak concentration (30 minutes after the end of an infusion) was 20.28 +/- 2.54 micrograms/mL, and the mean +/- S.D. half-life was 2.41 +/- 0.24 hours. The values for gentamicin alone did not differ significantly from those for gentamicin in any of the combination regimens. Coadministration of once-daily gentamicin and piperacillin-tazobactam in various i.v. infusion regimens did not affect the pharmacokinetics of once-daily gentamicin.

Adolescent↗

Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: implication for a reduction in mammary cancer risk.

Previous research showed that treatment with conjugated linoleic acid (CLA) during the period of active mammary gland morphogenesis was sufficient to confer a lasting protection against subsequent mammary tumorigenesis induced by methylnitrosourea. The present study was designed to characterize certain morphological and biochemical changes of the mammary gland that might potentially render it less susceptible to cancer induction. Female Sprague Dawley rats were fed a 1% CLA diet from weaning until about 50 days of age. The mammary gland parameters under investigation included (a) the deposition of neutral lipid, (b) the identification and quantification of CLA and its metabolites, (c) the density of the epithelium, and (d) the proliferative activity of various structural components. Our results showed that CLA treatment did not affect total fat deposition in the mammary tissue nor the extent of epithelial invasion into the surrounding fat pad but was able to cause a 20% reduction in the density of the ductal-lobular tree as determined by digitized image analysis of the whole mounts. This was accompanied by a suppression of bromodeoxyuridine labeling in the terminal end buds and lobuloalveolar buds. The recovery of desaturation and elongation products of CLA in the mammary gland confirmed our prior suggestion that the metabolism of CLA might be critical to risk modulation. The significance of the above findings was investigated in a mammary carcinogenesis bioassay with the use of the dimethylbenz[a]anthracene model. When CLA was started at weaning and continued for 6 months until the end of the experiment, this schedule of supplementation produced essentially the same magnitude of mammary tumor inhibition in the dimethylbenz[a]anthracene model as that produced by 1 month of CLA feeding from weaning. The observation is consistent with the hypothesis that exposure to CLA during the time of mammary gland maturation may modify the developmental potential of a subset of target cells that are normally susceptible to carcinogen-induced transformation.

9,10-Dimethyl-1,2-benzanthracene↗

Molecular Transport and SAPO-11 Crystal Growth in an i-Pr2NH-AlPO4-H3PO4-SiO2-H2O System

The crystal growth of SAPO-11 molecular sieve synthesized with i-Pr2NH as a novel template from mixtures of Si, Al, and P sources were studied by XRD, MAS-NMR, IR, and AAS techniques. It was found that the crystallization was improved partially by the desorption of i-Pr2NH from the crystallite products at high temperatures. The growth on (010) face was enhanced by stepwise adding external silica sol to the reaction mixtures during the synthesis process. The molecular transport and mechanism of the crystallization were discussed. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗

Molecular mechanism controlling the incorporation of fluorescent nucleotides into DNA by PCR.

The efficiency and yield of incorporation of fluorescent nucleotides into DNA by polymerase chain reaction (PCR) have been investigated with linear amplification (PCR with single-stranded template and single primer). In the present study, we prepared single-stranded templates with defined sequences and used dUTP attached to the fluorescent label with linkers of different lengths. Incorporation and yield of the modified dUTP were reduced when the sequence demanded that multiple dyes be inserted at adjacent sites. The interactions between the polymerase and cyanine-labeled sites on the extending strand probably terminated the chain extension. Thus, because labeling density was increased, the yield of PCR was reduced. We also found that the interactions between the primer and dye-labeled sites on template disturb primer annealing and lead to a decrease in PCR yield.

Base Sequence↗

Copper-specific transcriptional repression of yeast genes encoding critical components in the copper transport pathway.

Copper is an essential micronutrient that is toxic in excess. To maintain an adequate yet non-toxic concentration of copper, cells possess several modes of control. One involves copper uptake mediated by genes encoding proteins that play key roles in high affinity copper transport. These include the FRE1-encoded Cu2+/Fe3+ reductase and the CTR1 and CTR3-encoded membrane-associated copper transport proteins. Each of these genes is transcriptionally regulated as a function of copper availability: repressed when cells are grown in the presence of copper and highly activated during copper starvation. Our data demonstrate that repression of CTR3 transcription is exquisitely copper-sensitive and specific. Although copper represses CTR3 gene expression at picomolar metal concentrations, cadmium and mercury down-regulate CTR3 expression only at concentrations 3 orders magnitude greater. Furthermore, copper-starvation rapidly and potently induces CTR3 gene expression. We demonstrate that the CTR1, CTR3, and FRE1 genes involved in high affinity copper uptake share a common promoter element, TTTGCTC, which is necessary for both copper repression and copper-starvation activation of gene expression. Furthermore, the Mac1p is essential for down- or up-regulation of the copper-transport genes. In vivo footprinting studies reveal that the cis-acting element, termed CuRE (copper-response element), is occupied under copper-starvation and accessible to DNA modifying agents in response to copper repression, and that this regulated occupancy requires a functional MAC1 gene. Therefore, yeast cells coordinately express genes involved in high affinity copper transport through the action of a common signaling pathway.

Antiporters↗

Saccharomyces cerevisiae mutants altered in vacuole function are defective in copper detoxification and iron-responsive gene transcription.

The metal ions, Cu2+/+ and Fe3+/2+, are essential co-factors for a wide variety of enzymatic reactions. However, both metal ions are toxic when hyper-accumulated or maldistributed within cells due to their ability to generate damaging free radicals or through the displacement of other physiological metal ions from metalloproteins. Although copper transport into yeast cells is apparently independent of iron, the known dependence on Cu2+ for high affinity transport of Fe2+ into yeast cells has established a physiological link between these two trace metal ions. In this study we demonstrate that proteins encoded by genes previously demonstrated to play critical roles in vacuole assembly for acidification, PEP3, PEP5 and VMA3, are also required for normal copper and iron metal ion homeostasis. Yeast cells lacking a functional PEP3 or PEP5 gene are hypersensitive to copper and render the normally iron-repressible FET3 gene, encoding a multi-copper Fe(II) oxidase involved in Fe2+ transport, also repressible by exogenous copper ions. The inability of these same vacuolar mutant strains to repress FET3 mRNA levels in the presence of an iron-unresponsive allele of the AFT1 regulatory gene are consistent with alterations in the intracellular distribution of redox states of Fe3+/2+ in the presence of elevated extracellular concentrations of copper ions. Therefore, the yeast vacuole is an important organelle for maintaining the homeostatic convergence of the essential yet toxic copper and iron ions.

Adaptor Proteins, Vesicular Transport↗