Biomedical subjects

Z Liang

Publications and source records attributed to Z Liang.

At least 73 records · Page 4Linked to original sources

PubMed2000

[A molecular epidemiological investigation on Leptospira interrogans serovar hebdomadis and australia in China].

OBJECTIVE: In order to confirm whether cattle serve the source of infection for patients with Leptospira interrogans serovar hebdomadis and australia. METHODS: 12 field strains of leptospira interrogans serovar hebdomadis and australia were isolated from blood samples of patients with leptospirosis and farm cattle urine. An analysis of chromosome DNA restriction endonuclease patterns (REP) and restriction fragments length polymorphism (RFLP) of 16S + 23S rRNA gene were processed by digestion of chromosome DNA using EcoR I. RESULTS: The same serovar field strains of Leptospira interrogans from blood samples of patients with leptospirosis and farm cattle urine resulted in unique restriction endonuclease patterns (REP) and ribosomal types (RT). The chromosome DNAs from field strains that belonged to different serovars of Leptospira interrogans caused different restriction endonuclease patterns and ribosomal types. CONCLUSION: In accordance with this results, we recognize that farm cattle serve the infectious source of leptospirosis serovar hebdomadis and australia thus may have realistic significance in the control of leptospirosis serovar epidemic of hebdomadis and australia in China.

Animals↗

PubMed2000

[The susceptible alleles on HLA-DRB 1 of type I diabetes in children in Harbin].

OBJECTIVE: To evaluate association between type I diabetes in children and HLA-DRB1 alleles in Harbin. METHODS: Case-control method was employed, and the PCR-SSP technique was used to identify HLA-DRB1 alleles. RESULTS: The frequencies of DRB1 * 0301 and DR3/4 heterozygosity were significantly higher but the frequency of DR2 was significantly lower in cases than that in controls. In DR4 subtypes, the frequency of DRB1 * 0405 was higher and the frequency of DRB1 * 0406 was lower in cases than that in the controls. The difference between cases and controls in DRB1 * 0901 was not significant. CONCLUSION: DRB1 * 0301 allele and DR3/4 heterozygosity were the important susceptibility and heterozygosity genes while DR2 was the most important protective gene in Harbin. The DR4 possessed double-tendency. DRB1 * 0405 conferred susceptibility and DRB1 * 0406 conferred little protection. The susceptibility conferred by DRB1 * 0901 was not certain in type I diabetes in childhood in China. This study provided useful genetic data on the study of etiology of type I diabetes mellitus.

Alleles↗

PubMed2000

[Preparation of galactosyl-insulin with double saccharide density and a study of its hepatic targeting property].

This study was intended to improve the technical procedure so as to increase the saccharide density of galactosyl-recombinant insulin and elevate its liver targeting property. Using a branched compound 3,5-dihydroxy benzoic acid as the base of a conjugating bridge, the authors prepared a new double galactosyl-recombinant insulin, whose saccharide density being two times as high as that of galactosyl-recombinant insulin. The double gal-insulin conjugate, gal-insulin conjugate and original insulin were labeled with 131I, and then the three kinds of 131I labeled compounds were tested in rabbit whole body imaging to measure their properties of liver targeting. The peak values of rabbit liver concentration for double gal-insulin, gal-insulin and original insulin were 59.5%, 43.8% and 21.5%, respectively. These results demonstrate that for elevating the liver targeting property of galactosyl-recombinant compounds, a branched agent like 3,5-dihydroxyl benzoic acid can be adopted as an effective medium.

Animals↗

PubMed2000

[Preclinical pharmacological study of a novel myocardial perfusion agent: 99mTc-Q3].

In order to provide an experimental foundation for clinical study, we made a preclinical pharmacological investigation of 99mTc-Q3, a novel myocardial perfusion imaging agent, technetium-99m-N,N'-ethylenebis (acetylace-toneiminato) bis (tris (3-methoxy-1-proply) phosphine). After the preparation of this compound, the kinetics of blood clearance in rabbits, biodistribution in mice, measurement of plasma protein binding rate, and myocardial perfusion imaging in dog were carried out. The labelling efficiency and radiochemical purity measured were over 99%, and the stability (in vitro) was good and stable up to 6 hr of testing at room temperature. The pharmacokinetics met the two-compartment model with 0.23 +/- 0.09 ml/min of excellent blood clearance, an initial half-time of 1.5979 +/- 0.4182 min, and a late half-time of 203 +/- 25.83 min. The biodistribution as shown in myocardial accumulation was earlier, the radioactive value was higher, and once extracted, it remained relatively constant in the myocardium for at least 4 hr. The tracer was rapidly cleared from the blood, lung and the liver. The scintigraphy imaging in dog demonstrated that it was rapidly cleared from the lung, and the radioactive concentration approached that of background 1 hr after injection. At 15 min after injection, the myocardial imaging displayed clearly up to 3 hr. In vitro protein binding rate was low (7.13 +/- 0.42%). The tolerance of this drug in mice was 500 times as much as in humans. In conclusion, 99mTc-Q3 exhibits favorable stability, biological property and safety, so clinical study of this preparation as a myocardial perfusion imaging agent is worthwhile.

Animals↗

PubMed2000

[Methodological study on preparation of a novel myocardial perfusion imaging agent: 99mTc-Q3].

This study was intended to explore the methods of preparing technetium-99m-N, N'-ethylenebis (acetylacetoneiminato) bis [tris (3-methoxy-1-propyl) phosphine] (99mTc-Q3) as a newer cationic myocardial perfusion imaging agent. The optimum scheme of technetium labeling on the basis of exploring the effects of differently labeled conditions on radiochemical purity was established by a multivariate orthogonal experimental design. A newer agent for myocardial perfusion imaging was developed based on the optimum scheme by a stannous chloride reduction method. Preparation, separation, purification and quality control were performed by a chromatography. Experiments for stability (in vitro), sterility, apyrogen, safeness, and for imaging in animals were carried out. "A2B2C2" was chosen as the optimum scheme of this labeled complex. There each of A, B and C factors has significant effect on the radiochemical purity, and there is no one-class cross effect on the radiochemical purity between them. The labeling efficiency and radiochemical purity were measured over 99% labeled 10 min later (at R. T.). The stability (in vitro) was good and kept up to 4 hr or testing (range: 92%-99.37%). The prepared product was sterile, apyrogenic and safe. The scintigraphic imaging in rabbits demonstrated that the tracer accumulated early in the heart and the myocardial imaging displayed clearly up to 3 hr. The results of this methodological study demonstrate that not only high quality 99mTc-Q3 can be obtained but also a standardized procedure for labeling all kinds of 99mTc-agents can be set up, and on this basis, the one-step kit of 99mTc-Q3 may be developed.

Animals↗

PubMed2000

[Dynamic study of hepatocellular pathological change and uptake rate of 125I-insulin during experimental hepatocarcinogenesis].

This study was designed to observe the hepatocellular pathological change and uptake rate of 125I-insulin during experimental hepatocarcinogenesis in rats and clarify the possible mechanism of increasing uptake of 125I-insulin. 80 SD rats were divided into 2 groups, control and experimental groups. All of the rats were given common feed, and the rats of experimental group were given extra diethylnitrosamine (DENA) 70 mg/kg each week. At 6th, 11th, 15th and 20th week after start of the experiment, 10 control and 10 experimental rats were killed 1 hour post administration of 125I-insulin by tail vein. Blood, liver, lung, spleen, kidney, muscle and bone were collected; the radioactivity was measured and calculated %ID/g. The data of 2 groups were compared and examined with t-test. All of livers were pathologically examined. The results showed all livers of control group were normal. At 6th week, the surfaces of experimental rats' livers were coarse. Hepatocellular hyperplasia was observed, 125I-insulin-uptake rate was 1.86 time as much as that of control group. At 11th week, the liver's colour became lighter than that of control group. Hyperplasia and hepatocirrhosis were observed, 125I-insulin-uptake rate was 1.50 time as much as that of control group. At 15th week, hyperplastic nodules were observed in all experimental rats' livers. Hepatomacellulae were observed in 6 rat livers. 125I-insulin-uptake rate was 1.56 time as much as that of control group. At 20th week, the livers became enlarged out of shape. There were a lot of big or small greyish white nodules in all livers. Necrosis, liquefaction and hemorrhage were observed. Hepatomacellulae were observed in all of experimental rats livers. 125I-insulin-uptake rate was 1.46 time as much as that of control group. The differences of 125I-insulin-uptake rate between experimental and control groups were significant. These results demonstrated that the liver ability of uptaking 125I-insulin increased which mainly took place during the period of hepatocellular hyperplasia, and the hepatomacellulae kept this characteristic.

Animals↗

PubMed1999

Technical and clinical comparison of two fully automated methods for the immunoassay of CA 125 in serum.

The sensitivity and precision of two fully automated enzyme immunoassays, a chemiluminescent enzyme immunoassay (CLEIA) and an enzyme-linked immunosorbent assay (ELISA), for the determination of the ovarian carcinoma antigen CA 125 were evaluated by comparison with an immunoradiometric assay (IRMA). Sera were obtained from patients with ovarian carcinoma (N = 28 before treatment and N = 24 after treatment), digestive system cancer (N = 21 before treatment) and from healthy women (N = 90). The CLEIA showed a good agreement with the IRMA in terms of the positivity rate, accuracy and assay linearity, whereas the ELISA gave some false positive results. The mean value of CA 125 in the sera of healthy women was 14, 16 and 20 U/ml determined using the CLEIA, IRMA and ELISA procedures with standard deviations (SD) of 6.9, 7.3 and 8.8 U/ml, respectively. Both the reproducibility and precision of the CLEIA with coefficients of variation (CV) of 4.6% intra-assay and 7.6% inter-assay were better than those of the ELISA with CV of 6.2% intra-assay and 15.2% inter-assay (N = 16). We conclude that the CLEIA is the preferable method for CA 125 determinations and the diagnosis of ovarian carcinoma.

CA-125 Antigen↗

PubMed1999

The evolutionary history of carbamoyltransferases: A complex set of paralogous genes was already present in the last universal common ancestor.

Forty-four sequences of ornithine carbamoyltransferases (OTCases) and 33 sequences of aspartate carbamoyltransferases (ATCases) representing the three domains of life were multiply aligned and a phylogenetic tree was inferred from this multiple alignment. The global topology of the composite rooted tree (each enzyme family being used as an outgroup to root the other one) suggests that present-day genes are derived from paralogous ancestral genes which were already of the same size and argues against a mechanism of fusion of independent modules. A closer observation of the detailed topology shows that this tree could not be used to assess the actual order of organismal descent. Indeed, this tree displays a complex topology for many prokaryotic sequences, with polyphyly for Bacteria in both enzyme trees and for the Archaea in the OTCase tree. Moreover, representatives of the two prokaryotic Domains are found to be interspersed in various combinations in both enzyme trees. This complexity may be explained by assuming the occurrence of two subfamilies in the OTCase tree (OTC alpha and OTC beta) and two other ones in the ATCase tree (ATC I and ATC II). These subfamilies could have arisen from duplication and selective losses of some differentiated copies during the successive speciations. We suggest that Archaea and Eukaryotes share a common ancestor in which the ancestral copies giving the present-day ATC II/OTC beta combinations were present, whereas Bacteria comprise two classes: one containing the ATC II/OTC alpha combination and the other harboring the ATC I/OTC beta combination. Moreover, multiple horizontal gene transfers could have occurred rather recently amongst prokaryotes. Whichever the actual history of carbamoyltransferases, our data suggest that the last common ancestor to all extant life possessed differentiated copies of genes coding for both carbamoyltransferases, indicating it as a rather sophisticated organism.

Amino Acid Sequence↗

PubMed1999

A multifrequency electron spin resonance study of T4 lysozyme dynamics.

Electron spin resonance (ESR) spectroscopy at 250 GHz and 9 GHz is utilized to study the dynamics and local structural ordering of a nitroxide-labeled enzyme, T4 lysozyme (EC 3.2.1.17), in aqueous solution from 10 degrees C to 35 degrees C. Two separate derivatives, labeled at sites 44 and 69, were analyzed. The 250-GHz ESR spectra are well described by a microscopic ordering with macroscopic disordering (MOMD) model, which includes the influence of the tether connecting the probe to the protein. In the faster "time scale" of the 250-GHz ESR experiment, the overall rotational diffusion rate of the enzyme is too slow to significantly affect the spectrum, whereas for the 9-GHz ESR spectra, the overall rotational diffusion must be accounted for in the analysis. This is accomplished by using a slowly relaxing local structure model (SRLS) for the dynamics, wherein the tether motion and the overall motion are both included. In this way a simultaneous fit is successfully obtained for both the 250-GHz and 9-GHz ESR spectra. Two distinct motional/ordering modes of the probe are found for both lysozyme derivatives, indicating that the tether exists in two distinct conformations on the ESR time scale. The probe diffuses more rapidly about an axis perpendicular to its tether, which may result from fluctuations of the peptide backbone at the point of attachment of the spin probe.

Bacteriophage T4↗

PubMed1999

Determination of the nutraceutical, glucosamine hydrochloride, in raw materials, dosage forms and plasma using pre-column derivatization with ultraviolet HPLC.

A selective and specific high performance liquid chromatography method was developed to quantitate glucosamine hydrochloride in raw materials, dosage forms and plasma. Reverse phase chromatography using pre-column derivatization with phenylisothiocyanate, and ultraviolet detection (lambda = 254 nm) was used to quantify the eluate. The mobile phase consisted of MeOH/H2O/CH3COOH (10:89.6:0.04) and was pumped at a flow rate of 1.2 ml/min. The standard curves for glucosamine hydrochloride showed linearity (r > or = 0.99) over the selected concentration range from 6.65 to 16.63 microg/ml for raw materials and dosage forms. The precision of the dosage form assay, expressed as the % relative standard deviation (R.S.D.), was < 5% at all concentrations. The intra-day and inter-day accuracy, as indicated by the relative error (R.E.), ranged from - 2.54 to 2.70% for glucosamine hydrochloride. For the plasma assay, beagle dog plasma was used to prepare standard curves in the concentration range of 1.25-20 microg/ml. Precipitation of plasma proteins was accomplished with acetonitrile to separate interfering endogenous products from the compound of interest. The supernatant was derivatized using phenylisocyanate in phosphate buffer (pH = 8.3) and subsequently evaporated to dryness under a nitrogen stream at 42 degrees C. The residue was dissolved in 250 microl mobile phase and injected onto the chromatographic system. The assay was linear in concentration ranges of 1.25-20 microg/ml (r > or = 0.999). Intra- and inter-day precision was < or = 5.23 and 5.65%, respectively and the intra- and inter-day accuracy, indicated by R.E., ranged from - 8.6 to 10.35%. The method was found to be specific and with excellent linearity, accuracy and precision and is well suited for the quantitation of glucosamine hydrochloride in raw materials, dosage forms, and pharmacokinetic studies.

Acetonitriles↗

PubMed1999

A unified reconstruction framework for both parallel-beam and variable focal-length fan-beam collimators by a Cormack-type inversion of exponential radon transform.

A variety of inversions of exponential Radon transform has been derived based on the circular harmonic transform in Fourier space by several research groups. However, these inversions cannot be directly applied to deal with the reconstruction for fan-beam or variable-focal-length fan-beam collimator geometries in single photon emission computed tomography (SPECT). In this paper, we derived a Cormack-type inversion of the exponential Radon transform by employing the circular harmonic transform directly in the projection space and the image space instead of the Fourier space. Thus, a unified reconstruction framework is established for parallel-, fan-, and variable-focal-length fan-beam collimator geometries. Compared to many existing algorithms, the presented one greatly mitigates the difficulty of image reconstruction due to the complicated collimator geometry and significantly reduces the computational burden of the special functions, such as Chebyshev or Bessel functions. By the well-established fast-Fourier transform (FFT), our algorithm is very efficient, as demonstrated by several numerical simulations.

Algorithms↗

PubMed1999

Nucleotide structure and characterization of the murine gene encoding the endothelial cell protein C receptor.

The nucleotide sequence of the entire gene encoding the murine endothelial cell receptor for activated protein C (EPCR) has been determined. A total of 5303 bp of DNA was sequenced that included 4 exons and three introns, which constituted the coding region of the gene, as well as 393 bp upstream of the first exon and 841 bp downstream of the last exon. From the locations of the introns in this gene and analysis of the exon structures, it is clear the EPCR gene is a member of the CD1 class of multiple histocompatibility proteins. and its cDNA sequence is nearly identical to that of CCD41, a centrosome-associated protein. All elements needed for RNA polymerase II-based transcription are predicted to exist in the 5' uncoded region of the gene, and potential 3' regulatory sequences for efficient polyadenylation have been located at their optimal locations. A variety of highly probable transcription factor binding sites have been located in the 5' region of the gene. These data suggest that the EPCR gene is under efficient transcriptional control, and support the finding that this gene product may be involved in the inflammatory pathway.

Animals↗

PubMed1999

[Utilization of a pedicled labial flap, single or double face, for the management of post-obstetric urethral damage].

Reported here is our experience with a single or double-face new procedure using a pedicled labial flap for urethral reconstruction in patients treated for extensive urethral damage after obstetrical injury. Between January 1992 to July 1997, 56 cases of urethral damage on African female patients, with an average age of 18 years old, were treated by pedicled labial urethroplasty. This procedure was done by using a single or double-face pedicled flap obtained from the major or minor labia. The flap was then introduced as in a tunnel beneath the vaginal epithelium reaching the damaged urethra. A variety of techniques were proposed: patch for sufficient lengthening (27 cases), tubularized flap allowing complete reconstruction of the urethra (18 cases) and the double-face urethroplasty (11 cases). Good quality urine continence was obtained by using the sub urethral Martius'sling procedure. In 11 cases, we combined the treatment with a colposuspension procedure. The average follow-up was 23 months (ranging from 5 to 47 months). The global success was 82% (52 patients treated). Recovery of normal miction and absence of urinary leak was obtained in 36 cases (69%). While 7 moderate failures occurred (13%), 9 cases were considered complete failures (17%). In view of the high success rate, we consider that the one-stage procedure by the use of a single or double face pedicled labial flap is a choice treatment and highly suitable for the management of extensive urethral cervical damage after obstetrical injury.

Adolescent↗

PubMed1999

[Replacement of the superior vena cava with vascular prosthesis in surgical treatment of lung carcinoma].

OBJECTIVE: To investigate the effect, surgical technique and prognosis of replacement of the superior vena cava(SVC) with vascular prosthesis in surgical treatment of advanced lung carcinoma. METHODS: Twenty six patients with right lung carcinoma invading the SVC (central lung carcinoma in 21 cases, peripheral lung carcinoma in 5 cases) underwent radical resection of tumor with concomitant replacement of SVC with vascular prosthesis. All patients took a low dose of anticoagulant in short-term after operation. Long-term follow-up was conducted. RESULTS: All the cases had no intraoperative or postoperative early death, and no early or late obstruction of SVC. Follow-up was conducted in 23 cases. The overall survival rates at 1, 3 and 5 years were 85%(22/26), 39%(7/18) and 36%(4/11) respectively. CONCLUSIONS: Combination of resection of tumor and replacement of SVC enabled some cases of advanced lung carcinoma to achieve complete resection. This surgical technique extended the indications of surgical treatment of lung carcinoma, and increased the survival rate of advanced lung carcinoma. Further clinical applications are recommended.

Blood Vessel Prosthesis↗

PubMed1999

[Study of the relation between mutant gene in bile and hepatic metastasis of large intestinal carcinoma].

OBJECTIVE: To study the value of point mutant genes in the diagnosis of hepatic metastasis of large intestinal carcinoma. METHODS: Techniques of PCR-SSCP and DNA sequencing were used to detect point mutations of p53 and k-ras genes in primary focus, hepatic metastatic focus, and bile. RESULTS: 50 cases of large intestinal cancer were detected. 38 cases (76.0%) had p53 and k-ras gene mutations. p53 gene mutations were detected in 28 cases (56.0%) and k-ras gene mutations in 16 cases (32.0%). The same point mutant genes in bile with primary focus were detected in 10 out of 12 patients with hepatic metastasis (83.3%). CONCLUSIONS: The tumor cells of hepatic metastasis show the same clonal origin with primary focal cells that had same point mutant genes. Detection of the point mutant genes in bile is of value in the diagnosis of hepatic metastasis of large intestinal carcinoma.

Bile↗

PubMed1999

[A case-control study on Guillain-Barre syndrome in children of North China].

OBJECTIVE: This study aimed at exploring the risk factors for Guillain-Barre syndrome (GBS). METHODS: A case-control study design was used with 51 cases of GBS, diagnosed based on their symptoms, signs and electrophysiological examinations and exclusion of poliomyelitis and other acute flaccid paralysis, and 51 controls matched on age, sex and resident village. Serum IgG antibodies specific for Campylobacter jejuni were determined for all the subjects by enzyme-linked immunosorbent assay (ELISA) with a preparation of surface antigen of C. jejuni C(1) strain isolated from the patients and prevalent in north China. Each case and control were interviewed with his/her parents or guardians by a trained interviewer using an ad hoc questionnaire, including his/her demographic information, socioeconomic status, onset of the illness, and potential risk factors in their environment and personal hygiene. Data were analyzed with SAS software release 6.04 in a microcomputer. RESULTS: GBS was associated with a few factors, such as residential areas (45 of the 51 cases living in the rural areas, accounting for 88.2% of the total), polio and hepatitis B vaccine immunization before onset of the illness (with ORs of 7.27 and 3.14, respectively), no hand washing after defecation and before meals (with an OR of 6.15) and getting cold and going to the river or lake site before onset of the illness (with ORs of 13.75 and 12.20, respectively). Infection with Campylobacter jejuni associated strongly with the illness (with an OR of 9.5, P < 0.001). Thirty-five of the 51 cases had precursor symptoms before onset of the illness (68.6%). CONCLUSION: It suggests that occurrence of GBS may correlate to infection with Campylobacter jejuni and poor personal hygiene in children.

Antibodies, Bacterial↗

PubMed1999

[Autodetection of cell adhesion by light transmission].

To set up a new effective method for measuring the adhesion between red blood cells and vascular endothelial cells, we studied the relationship between adhesive red blood cells and light transmission by using Microscope-Photometric-Monolayer-Technique Elias-c Analyzer in our department. The results showed that the method of light transmission measurement on the adhesion between red blood cells and vascular endothelial cells is simple, effective and reliable.

Cell Adhesion↗

PubMed1999

[Analysis of rRNA gene restriction fragments length polymorphism of Leptospira in China].

Sixty-four Leptospira international and domestic reference strains, which belonging to fifty-four serovars, and twenty-seven field strains were examined by using EcoR I restriction endonuclease analysis of genomic DNA and restriction fragments length polymorphism of rRNA gene, fifty-six Leptospiral ribotypes(RTs) were described. Most serovars gave specific patterns. Serovars in the same serogroup possess common core-segments, but we found RTs of reference strains from China and other countries are different. Most field strains have RTs with correspond of reference strains, only a few bands were shown different if RTs were different. A notable result was that the field strains of serovar pomona have the same Rt as the international reference strain but different from the domestic reference strain.

China↗