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Biomedical subjects

C G Zhang

Publications and source records attributed to C G Zhang.

At least 19 recordsLinked to original sources
PubMed2005

Effect of petroleum-containing wastewater irrigation on bacterial diversities and enzymatic activities in a paddy soil irrigation area.

Effects of petroleum contamination on bacterial diversities and enzymatic activities in paddy soils were investigated in the Shenfu irrigation area, the largest area irrigated by oil-containing wastewater for more than 50 yr in northeastern China. Bacterial diversities were determined by conventional colony morphology typing techniques and 16S rDNA polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). Dehydrogenase, hydrogen peroxidase, polyphenol oxidase, urease, and substrate-induced respiration (SIR) were measured to evaluate the effects of petroleum-containing wastewater irrigation on soil biochemical characteristics. Results showed that paddy soil total petroleum hydrocarbon (TPH) concentration in the irrigation area varied from 277.11 to 5213.37 mg kg(-1) dry soil. Soil TPH concentration declined along the gradient of the irrigation channel from up- to downstream. At the current pollution level, the paddy soil TPH concentration was positively correlated with the colony forming units (CFU) of aerobic heterotrophic bacteria (AHB) (r = 0.928, p < 0.001) and the genetic diversity based on DGGE profiles (r = 0.655, p < 0.05). The bacterial diversities in the soils based on colony morphotypes of AHB also increased with TPH concentration (r = 0.598), but not significant statistically (p = 0.052). Analysis of soil enzyme activities indicated a significant positive correlation between soil TPH concentration and activities of dehydrogenases (r = 0.974, p < 0.001), hydrogen peroxidases (r = 0.957, p < 0.001), polyphenol oxidases (r = 0.886, p < 0.001), and SIR (r = 0.916, p < 0.001). On the contrary, the urease activity showed a negative correlation with paddy soil TPH concentration (r = -0.814, p = 0.002), and could be used as a sensitive indicator of petroleum contamination.

Agriculture↗
PubMed2005

SVM classification of human intergenic and gene sequences.

Despite constant improvement in prediction accuracy, gene-finding programs are still unable to provide automatic gene discovery with the desired correctness. This paper presents an analysis of gene and intergenic sequences from the point of view of language analysis, where gene and intergenic regions are regarded as two different subjects written in the four-letter alphabet {A,C,G,T}, and high frequency simple sequences are taken as keywords. A measurement alpha(l(tau)) was introduced to describe the relative repeat ratio of simple sequences. Threshold values were found for keyword selections. After eliminating 'noise', 178 short sequences were selected as keywords. DNA sequences are mapped to 178-dimensional Euclidean space, and SVM was used for prediction of gene regions. We showed by cross-validation that the program we developed could predict 93% of gene sequences with 7% false positives. When tested on a long genomic multi-gene sequence, our method improved nucleotide level specificity by 21%, and over 60% of predicted genes corresponded to actual genes.

Algorithms↗
PubMed2005

Finding keywords for intergenic and gene regions for human genome.

The analysis of functionally related sequences for conserved patterns is important for further research of different functional regions. This paper presents an analysis of genes and intergenic sequences from the point of view of linguistics analysis, where gene and intergenic regions are regarded as two different subjects written in the four-letter alphabet [A, C, G, T] and high-frequency simple sequences are taken as keywords. A measurement alpha[l(tau)] was introduced to describe the relative repeat ratio of simple sequences. Cutoff values were found for keywords selection. After eliminating "noise," 87 short sequences were selected as keywords for intergenic regions and 76 for gene regions.

Base Sequence↗
PubMed2001

The expression of ccn3 (nov) RNA and protein in the rat central nervous system is developmentally regulated.

AIMS: To establish the expression pattern of ccn3 (nov) in the central nervous system (CNS) of adult rats and to determine whether spatiotemporal variations in the expression of ccn3 (nov) are related to specific developmental stages and/or specific CNS functions. METHODS: The sites of ccn3 (nov) expression have been identified by in situ hybridisation using didoxigenin labelled cRNA and by the reverse transcription-polymerase chain reaction (RT-PCR). The rat CCN3 (NOV) protein was characterised by western blotting performed on brain extracts. The localisation of the CCN3 (NOV) protein in the brain was established by immunocytochemistry. RESULTS: Increased expression of ccn3 (nov) was detected in the developing brain of rats after birth, as shown by RT-PCR and immunocytochemistry analysis performed on a series of samples taken between day 5 (P5) and day 300 (P300), with a pronounced peak between P15 and P150, suggesting that CCN3 (NOV) might play a role in the maintenance or establishment of specific brain functions. The relatively high amounts of an N-terminal truncated CCN3 (NOV) related protein detected both in the brain tissues and cerebrospinal fluid suggested that post translational processing of CCN3 (NOV) might be particularly prevalent in the brain. Such processing might be of biological importance in the light of the previously reported growth stimulatory effects of N-terminal truncated CCN3 (NOV) isoforms. CONCLUSIONS: The postnatal differential expression of ccn3 (nov) in the brain of developing rats suggests that CCN3 (NOV) might be involved in the acquisition of specific functions. The rat species provides an as yet unequalled system for these studies. Because the CCN3 (NOV) protein is detected in restricted areas of the brain, it will be interesting to establish whether variations of ccn3 (nov) expression are associated with normal cognitive processes and whether ccn3 (nov) expression is affected by aging. In addition, because CCN3 (NOV) is found in the spinal cord and along the axonal processes, it will be of interest to determine the expression of the normal and truncated isoforms of CCN3 (NOV) in various pathological conditions, such as neurodegenerative diseases.

Animals↗
PubMed2001

[A new melanoma antigen-encoding gene subfamily in human chromosome X].

A lot of studies have been focused on the tumor-related genes. We have cloned a new melanoma antigen-encoding gene (MAGE) from human fetal liver of third trimester and subsequently found that it represented a new MAGE gene subfamily, named MAGE-D. The MAGE-D subfamily contained three orthologs including human MAGE-D1, rat SNERG-1 and mouse DLXIN-1, and two paralogs including human MAGE-D and human KIAA1114. All human members of MAGE-D subfamily are located in human chromosome Xp11.21-p11.23. Moreover, MAGE-D subfamily stands out from other known subfamilies MAGE-A, -B and -C of MAGE family in view of typical features such as exon/intron organization, absence of tumorspecific antigens, evolutionarily divergent in sequences. The identification of MAGE-D subfamily will be helpful in understanding the genesis of tumor.

Amino Acid Sequence↗
PubMed2001

[Cloning and expression of Aspergillus niger glucose oxidase gene in methylotrophic yeast].

The DNA fragment encoding A. niger glucose oxidase was amplified by PCR using A. niger genomic DNA as template, and was cloned into vector of pPIC9 for expression in Pichia pastoris. When transformed into methylotrophic yeast Pichia pastoris GS115, The constructed plasmid pPICGOD1 directed the synthesis and secretion of functionally active GOD. After induction in MM medium for 4 days, the GOD activity in the medium reached 30-40 u/mL. SDS-PAGE revealed that recombinant yeast GOD was expressed up to 60%-70% of the total soluble protein, and the secreted GOD could be purified to electrophoretic homogeneity with one purification step using Q Sepharose Fast Flow ion exchange chromatography. The recombinant yeast GOD had very high catalytic activity, showed about 1.6-fold increase of specific activity over the commercial A. niger GOD. Kinetic analysis clearly demonstrated that recombinant yeast GOD showed similar substrate affinity for glucose to A. niger GOD, but the turnover number of the GOD from yeast was determined to be much higher than that of A. niger GOD. In addition, the linear range of glucose electrode made with recombinant yeast GOD was efficiently widened due to the high catalytic activity of yeast GOD.

Aspergillus niger↗
PubMed2001

[Coding region cDNA sequence cloning of rat neuroglobin gene, its polymorphism feature and tissue expression profile analysis].

The coding region cDNA sequence of rat neuroglobin (NGB) was obtained by RT-PCR technique using a degeneracy PCR primer pair based on previously reported cDNA sequence of human and mouse NGB gene. Result demonstrated that the coding region cDNA sequence of rat NGB gene is 456 bp in length, which could encode a protein of 151 amino acids. The rat NGB gene is highly homology with mouse (96%) and human (88%) NGB gene. However, several polymorphism sites were also detected in the rat NGB coding region: 113 t/c [L38P], 133 a/g [N45D], 388 a/g[R130G], 417 t/c. The cDNA sequence of rat NGB gene has been registered in GenBank under the accession number AF333245. Moreover, highly expression level of rat NGB in brain, liver, kidney, heart and skeletal muscle was detected by using multiple tissue RT-PCR technique, indicating the functional importance of this novel gene.

Amino Acid Sequence↗
PubMed2000

Changes in lipid peroxidation, the redox system and ATPase activities in plasma membranes of rice seedling roots caused by lanthanum chloride.

Highly purified plasma membranes were isolated by aqueous two-phase partitioning from rice (Oryza sativa) seedling roots. The effects of lanthanum chloride (LaCl3) on the activities of lipid peroxidation, the redox system and H+-ATPase, Ca2+-ATPase of plasma membranes were studied. The lipid peroxidation of plasma membranes could be depressed by certain low concentrations of LaCl3 and enhanced by high concentrations of LaCl3, while the lipid peroxidation was also dependent on the plasma membrane protein and incubation time. The relative activity of O2 uptake of plasma membranes was inhibited by all tested LaCl3 concentrations. In contrast, the reduction rate of Fe(CN)6(3-) by plasma membranes was stimulated below 40 microM of LaCl3, but was reduced above 60 microM of LaCl3. The relative activities of both H+-ATPase and Ca2+-ATPase increased constantly from control to LaCl3 of concentration 60 microM where the activities of both enzymes were the maximum. but decreased remarkably at 80 microM LaCl3 concentrations various LaCl3 were added to culture solutions. In the other measurement case in which various LaCl3 concentrations were added directly to reaction medium and the plasma membrane vesicles only came from the control cultured rice seedling roots, the response of H+-ATPase activity to La3+ was similar to the response in culture solution. However, the La3+ concentration was only 20 microM when the activity of H+-ATPase was the maximum. In contrast to the case of LaCl3 addition to culture solution, Ca2+-ATPase activity was inhibited by all concentrations of La3+ which were added directly to the reaction medium. The above results revealed that REEs inhibited electron transfer from NADH to oxygen in plant plasma membranes, depressed the production of active oxygen radicals, and reduced the formation of lipid peroxides through plasma membrane lipid peroxidation. REEs ions also enhanced the H+ extrusion by both standard redox system and H+-ATPase in plasma membranes at certain concentrations. A possible role for the plant cell wall in REEs effects on plasma membranes was also suggested.

Calcium-Transporting ATPases↗
PubMed2000

[Relationships between learning and memory and expression of nov gene of rats].

During the establishment of learning and memory of adult rats with active avoidance reaction expression of nov gene, nov mRNA positive neurons and NOV protein immunoreactive neurons were found in hippocampus, cingulate cortex, globus pallidus, caudate putamen and hypothalamus. The strongest positive reaction of NOV protein was observed in high ability group of learning and memory (HALM). Basic expression was found in pseudoconditioning (PC) group. The expression of NOV protein was higher in low ability group of learning and memory (LALM) than in PC group. No significant difference was detected in nov mRNA positive reaction between the three groups. The results indicate that nov gene may play an important role in learning and memory of adult rats. This regulation occurs at the level of NOV protein translation.

Animals↗
PubMed2000

[Determination of catecholamine secreted from rat adrenal medulla by in vivo voltammetry].

In vivo voltammetry using carbon fiber electrodes was employed to determine the catecholamine secreted from the adrenal medulla. The basal level of catecholamine in the medulla was between 0.1 and 0.5 micromol/L, but it increased markedly up to 5 30 micromol/L when the gland was made ischemic. The spontaneous release of catecholamine from the medulla was observed in both normal and ischemia conditions, but the frequency and amplitude of spontaneous release were increased significantly by ischemia. This implied that the animal was under serious stress condition. The above results also show that acetylcholine can induce the secretion of catecholamine in a dose-dependent manner.

Acetylcholine↗
PubMed2000

[Real-time techniques in monitoring secretion activity in cells].

Chemical communication for neurons and endocrine cells depends on their secretion activity. Development of variety of biophysical techniques have greatly promoted the understanding of the mechanism of cellular secretion. Here we will introduce three recently developed biophysical techniques which have been frequently used to monitor secretion activity in real-time.

Cells↗
PubMed1998

A developmental study of novH gene expression in human central nervous system.

The expression pattern of the human nephroblastoma overexpressed (novH) gene in the fetal human central nervous system was examined by in situ hybridization using digoxigenin-labeled novH-specific riboprobes. In the spinal cord, the nov-expressing neurons were first detected both in the ventral region at 16 weeks of gestation (G16W) and in the dorsal region at G38W. In the medulla, nov-expressing neurons were detected in the principal nucleus of the inferior olive, the hypoglossal nucleus and the dorsal motor nucleus of vagus at G16W. Nov-positive neurons were detected at G28W in the nucleus of the spinal tract of the trigeminal and cuneate nucleus, and at G38W in the abducens nucleus of pons, the red nucleus and the substantia nigra of the midbrain, the ventral posterolateral and the mediodorsal thalamic nucleus. A strong labeling was also detected in the striatum of the cerebrum and the cerebral cortex of the parietal lobe. These data established that novH is mainly expressed in somato-motor neurons in the lower central nervous system at early developmental stages and in the higher central nervous system at later stages, suggesting that nov may play an important role in neuronal differentiation.

Central Nervous System↗
PubMed1998

Antimalarial activity of radicicol, heptelidic acid and other fungal metabolites.

In the course of our screening program for artemisinin-like antimalarial compounds from microorganisms, seven fungal metabolites such as radicicol and heptelidic acid were identified as active compounds. Some of them exhibited antimalarial activity in vitro against the human malaria parasite Plasmodium falciparum to the extent of approximately 1/10 as potent as artemisinin. Radicicol was moderately active in vivo against Plasmodium berghei in mice.

Animals↗
PubMed1998

Quantitative analysis of calcitonin gene-related peptide- and neuropeptide Y-immunoreactive nerve fibers in mesenteric blood vessels of rats irradiated with cobalt-60 gamma rays.

The effects of 60Co gamma rays on calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers and neuropeptide Y (NPY)-immunoreactive nerve fibers were examined in mesenteric blood vessels of rats. Using a free-floating immunostaining streptavidin-biotin peroxidase complex method combined with a nickel-enhancement technique, we found that the distribution pattern of these two peptidergic nerve fibers in superior mesenteric arteries and superior mesenteric veins did not change, while the densities of CGRP-immunoreactive nerve fibers and NPY-immunoreactive nerve fibers in superior mesenteric arteries and veins varied with the time after irradiation. The results suggested that CGRP and NPY may be important in the development and elimination of radiation-induced injury.

Animals↗
PubMed1998

Prospective study of simultaneous orthoiodohippurate and diethylenetriaminepentaacetic acid captopril renography. The Einstein/Cornell Collaborative Hypertension Group.

UNLABELLED: Captopril renography (CR) has been established in the past 10 yr as a useful diagnostic test for renovascular hypertension. However, direct comparison of tubular and glomerular tracers, quantitative criteria, comparison of quantitative and qualitative results and the reliability of the results in renal failure have not been described in a systematic, prospective fashion. METHODS: Same-day baseline and CR using 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) and [131I]orthoiodohippurate (OIH) were simultaneously performed in two groups of hypertensive subjects, one with demographically defined essential hypertension (n = 43) and the other (n = 60) with a high prevalence of renovascular disease, defined with angiograms. Quantitative criteria for abnormal CR were derived from results among the subjects with essential hypertension. Qualitative analysis was performed using widely established criteria. RESULTS: There were no statistically significant differences between quantitative and qualitative accuracy, between OIH and DTPA or among quantitative parameters. The best accuracies for quantitative CR were 56% with DTPA (n = 57) and 60% with OIH (n = 60), in both cases using the relative renal uptake parameter. Qualitative CR (n = 60) had accuracies of 43% (DTPA) and 50% (OIH), both hindered by 29 (DTPA) and 25 (OIH) abnormal but nondiagnostic studies. Two false-positive studies were detected. Twenty-seven of 29 nondiagnostic studies were associated with a glomerular filtration rate of <50 ml/min (n = 17), one small kidney (n = 17) and/or bilateral renal artery stenosis (n = 16). Supplemental measurement of in vitro stimulated plasma renin activity insignificantly (p > 0.10) and improved accuracies to 63% (DTPA) and 70% (OIH), without introducing additional false-positive tests. CONCLUSION: Orthoiodohippurate and DTPA have comparable accuracy in prospective simultaneous evaluation of CR. False-positive studies are fewer than 5%. The accuracies of quantitative and qualitative criteria do not differ significantly but may be improved by supplemental use of the in vitro stimulated plasma renin activity. In individuals with renal insufficiency, small kidneys and/or bilateral renal artery disease, up to 48% of CR studies are abnormal but nondiagnostic.

Antihypertensive Agents↗
PubMed1992

Precision of mean transit time measurements in 99Tcm-DTPA renal scintigraphy: a Monte Carlo study.

The precision of renal mean transit time (MTT) measurements by 99Tcm-DTPA scintigraphy was studied by a Monte Carlo procedure. Data were obtained from twenty mild essential hypertensives with normal renal function. An ensemble of equivalent data sequences was constructed for each renal time-activity curve (TAC), assuming the dominant noise in the data to be Poisson in character. TACS were deconvolved by the matrix method and MTT was inferred from retention functions by a procedure entailing a nonlinear least-squares minimization. For every ensemble of data sequences a distribution of MTTs was generated. The population-averaged coefficients of variation for these distributions were 1.6% and 2.6%, for whole-kidney and cortical data, respectively. We conclude that the precision of MTT determination from clinical data is comparable to that from simulated data. MTT measurements may be useful for detecting functional changes in individual kidneys following an intervention such as angiotensin-converting-enzyme inhibition.

Algorithms↗