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Biomedical subjects

Z Liang

Publications and source records attributed to Z Liang.

At least 91 records · Page 5Linked to original sources
PubMed1998

Pharmacokinetics and pharmacodynamics of mivacurium stereoisomers in beagle dogs using twitch height and train-of-four response.

Mivacurium, a non-depolarizing neuromuscular blocking agent, consists of three isomers; trans-trans (57%), cis-trans (36%) and cis-cis (7%). The purpose of this study was to characterize the pharmacokinetics and pharmacodynamics of mivacurium after various inputs. Four beagle dogs weighing between 7.95 and 9.89 kg were anesthetized with isofluorane (5%) and received a bolus dose (0.010-0.020 mg kg(-1)) and two constant rate infusions (1.0-1.5 microg kg(-1) min(-1)) of mivacurium via the saphenous vein. Single twitch height (TH) and train-of-four (TOF) were evaluated every 15 and 30 s, respectively. Arterial blood samples were collected, processed and analysed for mivacurium using a stereospecific HPLC-fluorescence method. The disposition of mivacurium isomers was best described by a two compartment model. Mean Cl for the cis-trans, trans-trans and cis-cis isomers were 19.98, 13.53 and 3.47 mL min(-1) kg(-1) respectively and the corresponding mean Vdss were 0.29, 0.24 and 1.00 L kg(-1). The measurement of onset showed dose dependence as evidenced by a rapid onset at the higher doses. TOF measurements were more sensitive to the onset of action and required a longer period of time to recover to baseline values as compared with TH measurements.

Anesthesia↗
PubMed1998

Effect of immune mechanisms on the pharmacokinetics and organ distribution of cryptococcal polysaccharide.

Cryptococcus neoformans is an encapsulated opportunistic fungus that can cause chronic infections accompanied by high tissue levels of capsular polysaccharide (CPS). CPS or its major component, glucuronoxylomannan (GXM), was administered to mice, and whole-body and tissue levels were measured. The role of monoclonal antibody (MAb), complement, and CD4 T cells in GXM clearance was also examined. These studies demonstrate that CPS is cleared from the blood within days but is retained in the body for weeks; that MAbs of all isotypes examined promote GXM clearance; that MAb-mediated GXM deposition in liver, but not in spleen, is Fc-dependent; that complement enhances IgM-mediated GXM sequestration in liver but not spleen; and that CD4 T cells are not necessary for serum GXM clearance. The results have important implications for the eventual use of MAbs in treatment of cryptococcosis.

Animals↗
PubMed1998

Quantitative cardiac SPECT in three dimensions: validation by experimental phantom studies.

A mathematical framework for quantitative SPECT (single photon emission computed tomography) reconstruction of the heart is presented. An efficient simultaneous compensation approach to the reconstruction task is described. The implementation of the approach on a digital computer is delineated. The approach was validated by experimental data acquired from chest phantoms. The phantoms consisted of a cylindrical elliptical tank of Plexiglass, a cardiac insert made of Plexiglass, a spine insert of packed bone meal and lung inserts made of styrofoam beads alone. Water bags were added to simulate different body characteristics. Comparison between the quantitative reconstruction and the conventional FBP (filtered backprojection) method was performed. The FBP reconstruction had a poor quantitative accuracy and varied for different body configurations. Significant improvement in reconstruction accuracy by the quantitative approach was demonstrated with a moderate computing time on a currently available desktop computer. Furthermore, the quantitative reconstruction was robust for different body characteristics. Therefore, the quantitative approach has the potential for clinical use.

Body Composition↗
PubMed1998

A harmonic decomposition reconstruction algorithm for spatially varying focal length collimators.

Spatially varying focal length fan-beam collimators can be used in single photon emission computed tomography to improve detection efficiency and to reduce reconstruction artifacts resulting from the truncation of projection data. It has been proven that there exists no convolution backprojection algorithm for this type of collimator, so a complicated interpolation between two nonparallel projection rays is necessary for existing algorithms. The interpolation may generate blurring and artifacts in the reconstructed images. Based on a harmonic decomposition technique and the translation property of Fourier series, a semifrequency resampling technique is proposed to avoid the above mentioned interpolations. By this technique, the harmonic decomposition of projection data for spatially varying focal length fan-beam collimators has the same form as that for parallel-beam collimators in the semifrequency domain (Fourier transform with respect to angular variables only). An alternative version of the inverse Cormack transform is then proposed to reconstruct the images. The derived reconstruction algorithm was implemented in a Pentium II/266 PC computer. Numerical simulations demonstrated its efficiency (3 s for 128 x 128 reconstruction arrays) and its robust performance (compared to the existing algorithms).

Algorithms↗
PubMed1998

Eve and ftz regulate a wide array of genes in blastoderm embryos: the selector homeoproteins directly or indirectly regulate most genes in Drosophila.

The selector homeoproteins are a highly conserved group of transcription factors found throughout the Eumetazoa. Previously, the Drosophila selector homeoproteins Eve and Ftz were shown to bind with similar specificities to all genes tested, including four genes chosen because they were thought to be unlikely targets of Eve and Ftz. Here, we demonstrate that the expression of these four unexpected targets is controlled by Eve and probably by the other selector homeoproteins as well. A correlation is observed between the level of DNA binding and the degree to which gene expression is regulated by Eve. Suspecting that the selector homeoproteins may affect many more genes than previously thought, we have characterized the expression of randomly selected genes at different stages of embryogenesis. At cellular blastoderm, 25-50% of genes whose transcription can be monitored are regulated by both Eve and Ftz. In late embryogenesis, 87% of genes are directly or indirectly controlled by most or all selector homeoproteins. We argue that this broad control of gene expression is essential to coordinate morphogenesis. Our results raise the possibility that each selector homeoprotein may directly regulate the expression of most genes.

Actins↗
PubMed1998

[Antibody reaction to immunization with different recombinant hepatitis B vaccine in primary school children].

OBJECTIVE: To evaluate the safety and immunogenicity of local produced hepatitis B (HB) vaccine and to lay a basis for formulating an immunization strategy. METHODS: Two batches of local produced and two batches of imported yeast derived recombinant HB vaccine (YDV), and four batches of local produced Chinese hamster ovary cell derived recombinant HB vaccine (CHOV) were administered to 550 children in primary schools to study their immunogenicity one year after immunization. RESULTS: No severe adverse reaction was found in all vaccinee. Positive seroconversion rate was more than 90 percent one month after completion of three-dose immunization with all kinds of HB vaccine mentioned above, and then declined slowly. Titer of antibody against hepatitis B surface antigen (anti-HBs) in those vaccinated with two batches of local produced YDV, except four groups, was significantly lower than that in those with imported YDV and local produced CHOV seven months after first-dose immunization, but no difference between local produced YDV and imported Merck vaccine and CHOV was found one year after immunization. Mean geometric titer (GMT) of anti-HBs reached the peak seven months after immunization in those vaccinated with all batches of HB vaccine except for the YDV imported from Amgen Co. There was no significant difference in positive seroconversion and GMT of anti-HBs between different batches of local produced YDV and CHOV. CONCLUSION: Safety and immnogenicity of local produced recombinant HB vaccine is as good as those of imported one in immunization for primary school children.

Child↗
PubMed1998

[The relation between nutrition and pulmonary ventilation in patients with chronic obstructive pulmonary disease during the relieved period].

To observe the effect of nutrition on pulmonary ventilation in aged patients with chronic obstructive pulmonary diseace (COPD) during the relieved period, the pulmonary function (MVV, PVC, FEV1, MMEF) of 261 aged patients with COPD was tested during the relieved period. The results showed that the MVV (48.75% +/- 19.9%) tested in the patients with malnutrition was significantly lower than that tested in the patients with normal nutrition (59.1% +/- 22.6%) (P < 0.01) while there was no marked difference in the ventilation in their large and small airway. It is conluded that malnutrition of the patients with COPD affects the constrictive function of respiratory muscle and thus results in a decrease in MVV.

Aged↗
PubMed1998

[Rapid microdose 14C-urea breath test for detection of Helicobacter pylori infection].

The purpose of this study was to develop and evaluate a rapid microdose 14C-urea breath test (14C-UBT) with a simplified protocol for detecting the infection of hilicobacter pylori (HP). 157 fasting patients who underwent endoscopy with histological examination and rapid urease test (RUT) were given a drink of 37 kBq of 14C-urea. Samples of breath carbon dioxide (1 mmol) were collected at baseline and 10, 20 and 30 min after administration by trapping in hyamine solution. 14C activity was measured by liquid scintillation counting. Results were expressed as cpm. Histolal examination and RUT were used as gold standard for the detection of HP infection. The cutoff value was selected as 200 cpm at 10 min. The results showed that the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 94.79%, 90.16%, 93.81%, 91.60% and 92.99% respectively. In this study, a 10 min, single sample, 37 kBq 14C-urea breath test for detection HP was developed. The test has good diagnostic accuracy with minimal radiation exposure and low cost. Thus, the authors considered the test to be reliable, safe, convenient and cost-effective to clinical use.

Adolescent↗
PubMed1998

[Mechanism of IL-6 secretion in bone marrow cells from multiple myeloma patients].

OBJECTIVE: To explore the mechanism of interleukin-6(IL-6) secretion in bone marrow cells from patients with multiple myeloma(MM). METHODS: Expression of IL-6 in bone marrow mononuclear cells(BMMNC) from MM patients(n = 16) and controls(n = 19) was detected by using double labelled immunofluorescence. RESULTS: In MM group, the positive rates of IL-6 expression were 15.4% +/- 6.5% in BMMNC, 7.9% +/- 2.9% in myeloma cells, and 4.5% +/- 1.2% in stromal cells, while in controls the positive rates were 4.6% +/- 2.3% in BMMNC, 2.6% +/- 1.1% in stromal cells and 0.7% +/- 0.1% in plasma cells, respectively. The positive rates in MM group were all significantly higher than those in controls(P < 0.001). The cytoplasmic IgG+ and vWF+ cells percentages in BMMNC were also significantly higher in MM group than those in controls. CONCLUSION: Elevated IL-6 in MM patients was secreted by both myeloma cells and stromal cells, and the mechanism of both autocrine and paracrine may be involved in pathogeneses of multiple myeloma.

Adult↗
PubMed1998

[TGF-beta 1 antisense gene transfer into ito cells and suppressed extracellular matrix production].

OBJECTIVE: To investigate possible role of antisense TGF-beta 1 RNA in the regulation of TGF-beta 1 and ECM production in Ito cells. METHOD: A human transforming growth factor-beta 1(TGF-beta 1) cDNA (1467 bp) was inserted in reverse orientation into the retroviral vector, constructed retroviral vector pLATSN of antisense RNA for TGF-beta 1. A higher-titer, recombinant retroviral vector carried antisense RNA for TGF-beta 1 produced in PA317 packaging cells has been introduced into human Ito cells lines LI90. After selection with G418, resistant colonies were obtained. RESULTS: Stable integration of retrovirus in infectants was shown the presence of antisense RNA was detected by RT-PCR. The expression of TGF-beta 1 protein and the production of extracellular matrix such as FN, Co1A1 were markedly decreased in the antisense TGF-beta 1 transfected cultured cells by ELISA, immunohistochemistry and in situ hybridization. CONCLUSION: Antisense RNA of TGF-beta 1 can be successfully used to inhibit Ito cells activated, endogenous TGF-beta 1 mRNA and extracellular matrix produced, and may provide a basis for the development of anti-fibrosis gene therapy.

Adipocytes↗
PubMed1998

The correlation between immune rejection and osteoinduction of allogeneic bone grafting.

OBJECTIVE: To evaluate the relationship between the immune rejection and the osteoinductive potential of bone allograft. METHODS: Allogeneic and syngeneic fresh bone, autolyzed antigen-extracted bone, bone matrix gelatin and demineralized bone matrix were implanted into the muscle of mice, and immunological tests, histological observation and alkaline phosphatase assay were performed. RESULTS: Three and 6 weeks after implantation, all kinds of allogeneic implants activated immune rejection, among them, fresh bone induced the most vigorous immune rejection and bone matrix gelatin caused the weakest response. Allogeneic autolyzed antigen-extracted bone, bone matrix gelatin and demineralized bone matrix inhibited proliferation of the lymphocytes in vitro and bone matrix gelatin had the most powerful inhibiting effect. Both allogeneic and syngeneic autolyzed antigen-extracted bone, bone matrix gelatin, and demineralized bone matrix induced heterotopic osteogenesis in vivo and bone matrix gelatin had the best osteoinductive capacity. CONCLUSION: There is a negative correlation between immune rejection to bone allograft and osteoinductive capacity of the graft.

Animals↗
PubMed1998

[Determination of sisomicin in body fluid by high performance liquid chromatography-indirect photometric detection method].

A high performance liquid chromatography-indirect photometric detection (HPLC-IPD) method for determination of sisomicin sulfate in body fluid (serum, urine, saliva, cerebrospinal fluid and fluid oozed out from wound) was established. The conditions in this method were a mobile phase solution of methyl alcohol-acetonitrile-water (20:10:70) containing nicotinamide 0.5 mmol/L, sodium 1-heptanesulfonate 5 mmol/L and phosphoric acid 0.05 mol/L, a Spherisorb C18 column (4.6 mm x 250 mm) and an UV detector with sensitivity of 0.05 Aufs (0.1 Aufs for urine). The detection wavelength was fixed at 268 nm. The average recovery for sisomicin in serum was 96.92% +/- 4.63% and the coefficients of variation were 4.75% and 5.65% for within-day and day-to-day tests respectively. The detectable limit was 0.1 ng. The concentration of sisomicin in body fluid of 4 patients was determined.

Anti-Bacterial Agents↗
PubMed1998

[Changes of T-SOD activity and MDA, GSH contents in blood of guinea pigs after exposure to narrow-band noise].

In order to evaluate the changes of lipid peroxide response induced by free radical after intense noise exposure, levels of T-SOD and MDA in serum and GSH in blood of guinea pigs were determined. Sixty male adult guinea pigs were used. The narrow band noise was centered at 1000Hz with 100Hz band width 126 dB SPL. It was found: 1) SOD activity in serum increased after 5d exposure (P > 0.05), but decreased after 10d exposure (P > 0. 05); 2) contents of MDA in serum increased (P < 0.05) and contents of GSH in blood decreased with increase of exposure time (P < 0.01). It shows that the lipid peroxide response induced by free radicals increased after intense noise exposure and it is possible to use free radical scavengers and/or antioxidant in prevention and treatment of noise induced damage.

Animals↗
PubMed1998

[Isolation and cloning of expressed sequences in a region flanking ANK1 on human chromosome 8p11.2].

OBJECTIVE: Our efforts were to isolate expressed sequences in a region flanking ANK1 on chromosome 8p11.2. METHODS: cDNA selection method was applied to isolate the expressed sequences from yeast artificial chromosomes(YAC) mapped to the region flanking ANK1 and one of the expressed sequences was isolated for the screening for human fetal brain cDNA library. RESULTS: Seven cDNA sequences were identified. Of these sequences, five were mapped back to their corresponding YAC. The remaining two sequences (BHLC26 and BHLC181) did not hybridize to any YAC used. BHLC152 was highly homologous to a gene for the musculus CArG box-binding factor. BHLC74 shared substantial identity with the gene encoding ventricular myosin alkali light chain 1 (MLC1), indicating that it might encode a MLC1 isoform. Partial sequence from other expressed sequences bore homology with some expressed sequences tagged with unknown function and without mapped data in the databases. BHLC119 was used as probe to screen cDNA libraries. One positive clone was sequenced. Its insert is 1,951 bp in length and encode a predicted 174 amino acids without homology with known proteins. One transcript of 3.5 kb was detected in total RNA from human fetal brain by Northern blotting. Tissue expression analysis suggests that it is a widely-expressed gene. CONCLUSION: BHLC74 may be considered a candidate gene for the 8p-related heart diseases. Other expressed sequences isolated might be used at least as candidates screening preliminarily for the tumor suppressor gene mapped to the region flanking ANK1 on 8p11.2.

Amino Acid Sequence↗
PubMed1998

Cloning and characterization of a cDNA encoding murine coagulation factor X.

The cDNA encoding murine coagulation factor X (fX) was isolated and reconstructed from a lambdaZap cDNA library generated from murine liver mRNA. The cDNA contains 1486 bases starting at the 5'-translation initiation codon. It includes an open reading frame of 1443 nucleotides, followed by an 18 residue 3' nontranslated sequence downstream of the first stop codon. and a 3' poly(A) tail. The translation product is composed of a 40-amino acid signal/propeptide region followed by a 441-residue mature protein. The latter is highly homologous to that of human and rat fX. All protein domains of human and rat fX are strictly conserved in mouse fX. The cDNA coding for mouse fX has been expressed in human embryonic kidney 293 cells and generates fX activity measured in a clotting assay using human fX-deficient plasma.

Amino Acid Sequence↗
PubMed1997

Pacifastin, a novel 155-kDa heterodimeric proteinase inhibitor containing a unique transferrin chain.

A 155-kDa proteinase inhibitor, pacifastin, from plasma of the freshwater crayfish, Pacifastacus leniusculus, was found to be composed of two covalently linked subunits. The two subunits are encoded by two different mRNAs, which were cloned and sequenced. The heavy chain of pacifastin (105 kDa) is related to transferrins, containing three transferrin lobes, two of which seem to be active for iron binding. The light chain of pacifastin (44 kDa) is the inhibitory subunit, and has nine cysteine-rich inhibitory domains that are homologous to each other and to low molecular weight proteinase inhibitors isolated from the grasshopper, Locusta migratoria. The nine light chain domains and the Locusta inhibitors share a characteristic cysteine array (Cys-Xaa9-12-Cys-Xaa2-Cys-Xaa-Cys-Xaa6-8-Cys-Xaa4++ +-Cys) distinct from any described proteinase inhibitor family, suggesting that they constitute a new family of proteinase inhibitors. Pacifastin is the first known protein that has combined properties of a transferrin-like molecule and a proteinase inhibitor.

Amino Acid Sequence↗