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Biomedical subjects

Z Jiang

Publications and source records attributed to Z Jiang.

At least 289 records · Page 16Linked to original sources
PubMed1994

Fusion expression vectors for recombinant gene products processed easily and purified rapidly by affinity chromatography.

A DNA fragment encoding IgG-binding domain B,C (PABC) was separated from protein A gene, cloned into phage M13 and modified by oligo-directed mutagenesis at the hydroxylamine-cleaved site from Asn-Gly to Asn-Ala in domain B and C, respectively. The modified PABCm gene fragment was used to construct one set of fusion expression vectors in different reading frames. Processing sequences such as those recognized by enterkinase, collagenase, thrombin, activated factor X and cleaved by the hydroxylamine, N-chlorosuccinimide etc. can be created in the fusion site. Using the above vectors, fusion proteins such as PABCm-IGF-I, -hGRF, -bGRF and their derivatives were highly expressed in E. coli. The yield of fusion proteins is over 100 mg per liter cultured by analysis of SDS-PAGE. The PABC fusion proteins can be rapidly purified by the affinity chromatography with a IgG-sepharose column.

Base Sequence↗
PubMed1994

[Simultaneous determination of serum copper and zinc levels in patients with cancer of the digestive tract by ion-exchange chromatography].

Serum copper and zinc were simultaneously determined by ion-exchange chromatography (IC) in 35 normal volunteers and 45 patients with benign diseases or different stage cancers of the digestive tract. No significant differences of serum Cu, Zn and Cu/Zn ratio were found among normal volunteers, patients with benign diseases and those with stage I or II cancers, while in the group of stage III and IV cancer patients, serum Cu (26.53 +/- 1.41 mumol/L) and Cu/Zn ratio (2.25 +/- 0.16) were very significantly elevated (P < 0.01) and that of serum Zn (11.78 +/- 0.46 mumol/L) was remarkably decreased (P < 0.05). Our results showed that serum Cu, Zn and Cu/Zn ratio were of no help in detecting early stage cancers and in differentiating them from benign diseases but were useful in predicting stages of cancers before operation for a better choice of therapy.

Adult↗
PubMed1994

The dynamic change of plasma endothelin-1 during the perioperative period in patients with rheumatic valvular disease and secondary pulmonary hypertension.

The arterial plasma endothelin-1 concentration was substantially more elevated in 15 patients with rheumatic valvular disease and secondary pulmonary hypertension than in healthy volunteers (3.66 +/- 2.20 versus 1.17 +/- 0.38 pg/ml, mean +/- standard deviation; p < 0.01). The preoperative plasma endothelin-1 level was highly correlated with the pulmonary hemodynamics: pulmonary artery systolic pressure (r = 0.94, p < 0.001), pulmonary artery mean pressure (r = 0.86, p < 0.001), pulmonary capillary wedge pressure (r = 0.82, p < 0.001), and pulmonary vascular resistance (r = 0.63, p < 0.02). After valve replacement, the plasma endothelin-1 concentration declined substantially and the pulmonary hemodynamics improved markedly. Two weeks after the operation, the plasma endothelin-1 level in patients (1.26 +/- 0.45 pg/ml, mean +/- standard deviation) was not statistically different from that in the healthy volunteers. The plasma endothelin-1 concentration continuously increased during the course of cardiopulmonary bypass and peaked after cessation of bypass. The peak plasma endothelin-1 level (13.49 +/- 4.60 pg/ml, mean +/- standard deviation) positively correlated with the bypass time (r = 0.64, p < 0.02) and negatively correlated with the urine volume during bypass (r = -0.69, p < 0.01). We conclude that (1) increased plasma endothelin-1 might be implicated in the pathogenesis of secondary pulmonary hypertension caused by rheumatic valvular disease and (2) markedly elevated plasma endothelin-1 concentrations might be associated with the mechanism of cardiac or renal dysfunction after prolonged cardiopulmonary bypass.

Adult↗
PubMed1994

Clinical observation on osteoporosis treated with traditional kidney-tonifying medicaments.

The method of scoring kidney deficiency symptoms and bone density was used to judge therapeutic efficacy on osteoporosis of traditional kidney-tonifying drugs. It was proved that the drugs not only improved clinical symptoms but also delayed the developmental process of this disorder. It also verified the correctness of the traditional theory that the kidney dominates the bone and generates the marrow.

Adult↗
PubMed1993

Dynamic 13C NMR analysis of oxidative metabolism in the in vivo canine myocardium.

Oxidative metabolism in the in vivo canine myocardium was studied noninvasively using 13C-enriched acetate and non-steady state 13C NMR techniques. Under low workload conditions, the myocardium oxidized the infused [2-13C]acetate and incorporated the labeled carbon into the glutamate pool as expected. This conclusion stems from the rapid enrichment of the C-2, C-3, and C-4 carbons of glutamic acid both under in vivo conditions and in extracts. Surprisingly, [2-13C]acetate uptake was not observed at high workloads as reflected by an absence of glutamate pool enrichment at these rate pressure products. Rather, the myocardium selected its substrate from an endogenous pool. Since free acetate can directly cross the inner mitochondrial membrane and be converted to acetyl-CoA through acetyl-CoA synthetase, these results support workload-dependent regulation of substrate access to the mitochondrial CoASH pool. As such, we advance the hypothesis that the selection of substrate for condensation with CoASH and subsequent oxidation in the tricarboxylic acid cycle is regulated kinetically through the Km values of the appropriate condensation enzymes and through the absolute levels of free CoASH in the mitochondria.

Animals↗
PubMed1993

Functional ecdysone receptor is the product of EcR and Ultraspiracle genes.

Although the biological activity of the insect moulting hormone ecdysone, is manifested through a hormonally regulated transcriptional cascade associated with chromosomal puffing, a direct association of the receptor with the puff has yet to be established. The cloned ecdysone receptor (EcR) is by itself incapable of high-affinity DNA binding or transcriptional activation. Rather, these activities are dependent on heterodimer formation with Ultraspiracle (USP) the insect homologue of vertebrate retinoid X receptor. Here we report that native EcR and USP are co-localized on ecdysone-responsive loci of polytene chromosomes. Moreover, we show that natural ecdysones selectively promote physical association between EcR and USP, and conversely, that high-affinity hormone binding requires both EcR and USP. Replacement of USP with retinoid X receptor produces heterodimers with distinct pharmacological and functional properties. These results redefine the ecdysone receptor as a dynamic complex whose activity may be altered by combinatorial interactions among subunits and ligand.

Animals↗
PubMed1993

Is atrial pacing needed for determination of coronary flow reserve by parametric imaging?

Heart rate changes during determination of coronary flow by parametric imaging may influence the flow measurement. Thus, the question is whether atrial pacing is mandatory for determination of coronary flow reserve (CFR) by this technique. CFR was calculated by digital subtraction angiography (parametric imaging) in 10 patients (8 with coronary artery disease and 2 control subjects) during sinus rhythm and during atrial pacing. Flow measurements were determined in the perfusion region of the left anterior descending and circumflex coronary artery, both at rest and after maximal coronary vasodilation with 10 mg intracoronary papaverine. CFR was defined as coronary flow during hyperemia divided by coronary flow at rest. Spontaneous heart rate was 71 +/- 15 min-1 at baseline, 73 +/- 15 min-1 after papaverine injection and 85 +/- 10 min-1 during atrial pacing. Heart rate variations during coronary arteriography were 4 +/- 3 min-1 at baseline and 5 +/- 4 min-1 after papaverine administration. CFR was 2.61 +/- 1.01 during sinus rhythm and 2.67 +/- 1.05 during atrial pacing. Mean absolute difference in CFR between sinus rhythm and atrial pacing was 0.31 +/- 0.31 (12 +/- 10% of CFR during pacing). Spontaneous heart rate variations during coronary arteriography are not associated with significant changes in CFR. Thus, atrial pacing is not mandatory for the determination of CFR by parametric imaging.

Angiography, Digital Subtraction↗
PubMed1993

Acute motor axonal neuropathy: a frequent cause of acute flaccid paralysis in China.

In northern China, annual epidemics of acute-onset flaccid paralysis diagnosed clinically as Guillain-Barré syndrome have been recognized for at least 20 years. On the basis of an historical analysis of more than 3,200 patients, distinctive features include most cases occurring during the summer months among children and young adults, most of whom reside in rural areas. Of 90 patients with acute flaccid paralysis, 88 had a distinctive pattern that shares clinical and cerebrospinal fluid findings with demyelinating Guillain-Barré syndrome, but that differs from Guillain-Barré syndrome physiologically and pathologically. The clinical course is marked by rapidly progressive ascending tetraparesis, often with respiratory failure, but without fever, systemic illness, or sensory involvement. Cerebrospinal fluid is acellular, and elevations of protein content occur in the second or third week of illness. Electrodiagnostic studies show normal motor distal latencies and limb conduction velocities, but reduced compound muscle action potential amplitudes. Sensory nerve action potentials and, when elicitable, F waves are within the range of normal. Recovery is usually good. Autopsy studies have shown Wallerian-like degeneration of motor fibers. These studies establish that this is a distinctive syndrome, distinguishable from poliomyelitis and demyelinating Guillain-Barré syndrome.

Acute Disease↗
PubMed1993

A graphical user interface to facilitate patient-specific drug dosing.

This paper describes the development of a graphical user-interface (GUI) designed to facilitate the process of generating patient-specific drug doses using bayesian modelling software. The graphical user interface was developed in Visual Basic (Microsoft, Inc.) and runs under the Windows 3.1 (Microsoft, Inc.) operating system. Patient demographic data are stored in a relational database (Access, Microsoft, Inc.). The GUI and the database communicate via dynamic data exchange links. The largely object-oriented nature of the language allowed us to change the entire look and feel of the system with a few simple changes to the underlying code. Use of the relational database to store patient demographic information allows greater flexibility in searching for and displaying patient specific information. The GUI reduces the time required to enter data. The prototype has allowed us to experiment with different presentation methods, greatly improving the clinical acceptance of the dosing programs.

Computer Simulation↗
PubMed1993

Interactive intraoperative localization using an infrared-based system.

We discuss new methods of localizing and treating brain lesions for both the conventional method of a base-ring fixed to the patient's skull (referred to as frame-based procedures) and the new method of frameless procedures (no base ring). Frame-based procedures are used for finding a precise instrument position during neurosurgical procedures, such as stereotactic biopsy of deep-seated lesions, placing electrodes for functional stereotaxis or catheters with radioactive seeds for brachytherapy, or even the placement of a stereotactic retractor or endoscope for removal or internal decompression of lesions. In such procedures, the intraoperative image localization of instruments becomes useful as it tracks instruments as they travel through the preplanned trajectory. Additional intraoperative digitization of surgical instruments, e.g., bipolar suction, biopsy forceps, microscope, ultrasound probe, etc, can be achieved during the stereotactic resection of eloquent areas or deep intracranial lesions by adding an infrared-based system. Frameless procedures broaden the range of surgical approaches, image guidance planning, and operative procedures, since no ring is attached to the patient's head which might interfere with the surgical approach, and offers logistic advantages in scheduling diagnostic studies. Frameless diagnostic studies employ anatomical markers and/or surface matching techniques for data registration in the computer software surgical preplanning program. This simplifies scheduling of the procedures since the image study does not need to be acquired the same day as surgery. Frameless diagnostic studies allow for the use of more than one type of imaging data for planning and optimization of surgical procedures, and greatly improve patient tolerance and comfort during these procedures and during surgery, as compared with frame-based procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Analog-Digital Conversion↗
PubMed1993

Schizophrenic delusions among Koreans, Korean-Chinese and Chinese: a transcultural study.

In this transcultural study of schizophrenic delusions among Koreans, Korean-Chinese and Chinese, many delusions were shown to be different among the three groups in their frequency and content and the differences could be explained by sociocultural and political factors. Delusional themes sensitive to influence by sociocultural or political situations and changes seem to be 'family', 'love affairs', 'religious matters', 'economic matters', 'specific physical damage' and 'political themes.' Delusions about 'family', 'love affair', 'being raped', 'religious matters' and 'economic and business matters' were most frequent in Koreans. Delusions of 'blood-relatedness', 'longevity' and 'political themes' were most frequent in Korean-Chinese. Delusions of 'bloodsucking and brain or viscera extracted' and 'poison or being pricked by poisoned needle' were most prominent in Chinese.

Adult↗
PubMed1993

[New oxindole alkaloid glycosides from Uncaria sinensis].

Two 16-carboxy derivatives of pentacyclic oxindole alkaloids and its glucopyranosyl esters have been isolated from the ethanolic extract of the leaves of Uncaria sinensis (Olive.) Havil. These structures were deduced on the basis of spectroscopic evidences and chemical correlations, and named mitraphyllic acid (I), isomitraphyllic acid (II), isomitraphyllic acid (16-1)-beta-D-glucopyranosyl ester (III) and mitraphyllic acid (16-1)-beta-D-glucopyranosyl ester (IV).

Drugs, Chinese Herbal↗
PubMed1993

[The hypoglycemic effect of AH-9].

AH-9 is an acylhydrazine compound with hypoglycemic effects in normal mice, alloxan-induced diabetic mice and spontaneously diabetic KK mice. In terms of equi-molar doses (0.3 mmol/kg po), AH-9 was found to be more potent than phenfornin and glicalazide (diamicron) in normal mice. Insulin resistance was shown to be improved in spontaneously diabetic KK mice and hydrocortisone-induced insulin resistant mice after treatment with AH-9. The LD 50 of AH-9 given orally to mice was found to be 956 mg/kg (about 18 times its effective dose). Studies on the hypoglycemic mechanism of AH-9 (insulin release, insulin receptor and post-receptor) showed that AH-9 did not influence serum insulin levels in mice. But, in in vivo experiments, AH-9 appeared to promote the capacity and affinity of insulin receptors in mouse liver plasma membranes. AH-9 was also found to antagonize the elevation of blood glucose level and liver glycogen content caused by alanine injection. AH-9 was shown to enhance the conversion of U-14C-glucose to 14CO2 in mouse epididymal fat tissue in vitro. According to the above results, the hypoglycemic action of AH-9 might be due to: 1) increasing the capacity and affinity of insulin receptors; 2) directly enhancing glucose aerobic oxidation; and 3) inhibiting gluconeogenesis.

Animals↗
PubMed1993

[The antioxidant action of AH-9].

AH-9 is a compound with hypoglycemic action. AH-9 was also found to have antioxidant activity. The hemolysis, hemoglobin oxidation and lipid peroxidation of erythrocytes induced by hydrogen peroxide and Fe(++)-induced MDA formation of liver microsomes were inhibited by AH-9, and the activity of SOD and catalase were shown to be increased in normal and alloxan-diabetic mice after treatment with AH-9. The above results indicate that AH-9 might act as a scavenger of superoxide and might be useful for improving the pathophysiological state in diabetes mellitus and its complications.

Animals↗
PubMed1993

[Development of hybridomas secreting monoclonal anti-idiotypic antibodies that bear the internal image of the terminal trisaccharide of PGL-I].

Two hybridomas designated as F7B7 and F7B9 secreting monoclonal anti-idiotypic antibodies against terminal trisaccharide of PGL-I were developed by fusion of SP2/0 cells and spleen cells of BALB/c mouse immunized with mouse monoclonal anti-trisaccharide of PGL-I (MAb1-E10F1). To characterize the F7B7, the following results were obtained. First, F7B7 reacted with MAb1-E10F1 specifically. Secondly, the cross ELISA neutralizing tests gave positive results. The binding of anti-trisaccharide positive serum with trisaccharide (contained in semi-synthetic antigen, NT-O-BSA) was inhibited F7B7 and the degree of inhibition showed dose-dependent manner. The binding of anti-trisaccharide positive serum with F7B7 was inhibited by NT-O-BSA and the degree of inhibition also showed dose-dependent manner. It was concluded that the hybridoma F7B7 is able to secrete monoclonal anti-idiotypic antibodies that bear the internal image of trisaccharide of PGL-I. The potentials and advantages of monoclonal anti-idiotypic antibody F7B7 as surrogate antigen in the serodiagnosis of leprosy have been discussed.

Animals↗
PubMed1992

New calcium-sensitive ligand for nuclear magnetic resonance spectroscopy.

Fluorinated calcium-sensitive indicators such as 5,5'-difluoro-1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (difluoro-BAPTA) will often be less sensitive under in vivo conditions than gyromagnetic ratio considerations alone would have predicted. This is due to the very broad line widths displayed by these molecules within the living cell. In order to provide a spectroscopic alternative to these molecules, we have synthesized 13C-enriched 1-(2-aminophenoxy)-2-(2-aminoethoxy)ethane-N,N,N',N'-tetraac etic acid or AATA. The rationale for the design of this molecule was the increased signal to noise ratio available by selective detection of 13C-attached protons in AATA using proton-observe carbon-edited spectroscopy or multiple-quantum coherence. AATA has the advantage of increased number of detectable nuclei and narrow line widths. As such, it should provide a 6-10-fold improvement in the signal to noise ratio over existing fluorinated indicators. As a hybrid between EGTA and BAPTA, AATA should display intermediate pKa's, exchange rates, and KD values. We have measured pKa values of 5.94 +/- 0.05 and 9.03 +/- 0.05 for AATA. KD values of 350 +/- 80 nM and 6.6 +/- 2.0 mM were obtained for the AATA-Ca2+ and AATA-Mg2+ interactions, respectively, at 37 degrees C in 0.1 M KCl. As such, this new ligand displays the expected selectivity for Ca2+ over Mg2+. This new approach to detection of intracellular probes with NMR can be readily extended to other probes for intracellular ions, pH, and membrane potential. In addition, the move toward carbon-selected proton spectroscopy should also permit more flexibility in synthetic approaches since the strong electronegativity of fluorine often hampers synthetic design.

Calcium↗