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Biomedical subjects

Y Cheng

Publications and source records attributed to Y Cheng.

At least 235 records · Page 13Linked to original sources
PubMed1996

[Changes in plasma endothelin-1 and lipid peroxidate levels and amount of superoxidate dismutase in red blood cell in patients with pregnancy-induced hypertension].

OBJECTIVE: To evaluate the role of endothelin (ET-1) and lipid peroxide (LPO) in the pathogenesis of pregnancy-induced hypertension (PIH). METHODS: The plasma concentrations of ET-1, LPO and the amount of superoxide dismutase (SOD) in red blood cell were measured by radioimmunoassay, thiobarbituric acid fluorimetric determination and catechol self-oxidation determination respectively in total 95 women (normal non-pregnant women 15, Late pregnant women 20 and patients with PIH 60). RESULTS: (1) The levels of ET-1, LPO and SOD in normal late pregnant women were significantly higher than those in non-pregnant women (P < 0.01), but the LPO/SOD ratio was not significantly different between the two groups. (2) The levels of plasma ET-1 and LPO/SOD ratio in cases with PIH were markedly higher than those in normal late pregnant women, and it increased with the severity of the disease and returned to the levels of normal late pregnant women within 3-7 days after delivery. (3) There was a positive correlation between ET-1 and LPO/SOD ratio in PIH. CONCLUSIONS: The imbalance of oxidation and antioxidation and endothelial cell injury may play an important role in the pathogenesis of PIH.

Adult↗
PubMed1996

[Effects of stress on indices for assessing zinc nutrition status].

To evaluate the specificity of some functional indices in assessment of body zinc nutrition status, we used experimental rat model to observe the effects of some factors, such as forced swimming, starvation, trauma and alcohol intoxication on zinc the status. Plasma zinc levels of rats significantly decreased after trauma increased after starvation. Liver zinc content showed a rising tendency in trauma and starvation rats. Activities of superoxide dismutase in red blood cells and alkaline phosphatase, mannosidase, 5'-nucleotidase in plasma of rats with alcohol intoxication declined significantly. Starvation led to decreased activities of alkaline phosphatase and angiotensin-converting enzyme, but increased activities of mannosidase. Trauma and forced swimming could cause increase of angiotensin-converting enzyme activity and decrease of 5'-nucleotidase activity, respectively. These results indicate that physiological and pathological effects should be excluded from of the above indices as plasma zinc index, in the assessment of body zinc nutrition status.

Alkaline Phosphatase↗
PubMed1996

Atomic force microscopic study on topological structures of pBR322 DNA.

Plasmid pBR322 DNA (0.5 mg/mL) isolated from Escherichia coli HB101 was suspended in Tris-HCI-EDTA (1 mol/L-0.1 mol/L, pH 8.5); then a drop of the above solution was deposited on freshly cleaved mica substrate. After adsorption for about 1 mm, the sample was stained with phosphotungstic acid. The residual solution was removed with a piece of filter paper. Afterwards the sample was imaged with a home-made atomic force microscope (AFM) in air. The AFM images of pBR322 DNA with a molecular resolution have been obtained. These images show that pBR322 DNA exists in several different topological structures: (i) relaxed circular DNA with a different diameter; (ii) supercondensed DNA with different particle sizes; (iii) dimeric catenane connected by one relaxed circular molecule and another close-compacted molecule which might be either supercoiled or intramolecular knotted form; (iv) oligomeric catenane with multiple irregular molecules in which DNA is interlocked into a complex oligomer; (v) possibly-existing intermediates formed from monomer to oligomer.

DNA, Bacterial↗
PubMed1996

Transformation of Pleurotus sapidus protoplasts by electroporation.

The total DNA of Pleurotus ostreatus was successfully transferred into the protoplasts of monokaryotic mycelia of Pleurotus sapidus by electroporation. The transformants were selected by their clamp connection of dikaryocyte, and the transformation frequency and transformation rate were 8.2 x 10(-5) and 3.6%, respectively. Analyzing the esterase isozyme, it was found that the transformants showed some isozyme bands of P. ostreatus and P. sapidus, and new non-parental bands. This proved that the recombination occurred between the DNAs of P. sapidus and P. ostreatus. The fruit bodies of the transformants showed morphological changes.

Electroporation↗
PubMed1996

[The imaging features of multiple endocrine neoplasia].

The article describes ultrasonographic (US), computed tomographic (CT), 99mTc-MIBI and angiographic findings of 16 cases of multiple endocrine neoplasia (MEN) confirmed by operations and pathological examinations. Hyperparathyroidism either was the first manifestation of MEN I or was diagnosed simultaneously with other tumors. Medullary thyroid carcinoma usually developed first or coincided with pheochromocytoma in MEN I. Regular US and CT screening can lead to the detection of new endocrine neoplasia. The authors consider that US and CT are the best imaging methods for MEN.

Adenoma↗
PubMed1996

[Characterization of renal pelvic carcinoma with US and color Doppler flow imaging].

Ultrasonography (US) was utilized to assess 22 patients with renal pelvic carcinomas, The neoplasms were demonstrated as hypoechoic mass in 81.82%, and as visualized hyperechoic mass in 18.18%; Their echogenicity was highly correlated with gross pathology. Among all the cases, 5 patients were investigated with color Doppler Flow Imaging (CDFI), and none of them demonstrated the high-frequency Doppler shifted signals seen in renal cell carcinomas. Therefore CDFI may help to differentiate renal pelvic carcinomas from renal cell carcinomas.

Adult↗
PubMed1995

pH dependence of specific divalent anion binding to the N-lobe of recombinant human transferrin.

The binding of the two synergistic anion mimics, phosphate and sulfate, and of the synergistic anions, malonate and oxalate, to the N-lobe of recombinant human serum transferrin (hTF/2N) wild-type and H207E mutant protein was assessed by difference ultraviolet (UV) spectroscopy at 246 nm as a function of pH. The absolute values of both the maximum delta epsilon 246 and the Kd decreased with decreasing pH. A plot of -log Kd vs pH gave a straight line with a slope of -1.0. Furthermore, the sum of -log Kd and pH is a constant for each anion binding to each protein. We interpret these data to mean that each anion binds in divalent form along with an H+. The binding equilibrium then appears to be H+ + hTF/2N + X2- reversible K' H-hTF/2N(X) and log K' = -log Kd + pH. A plot of delta epsilon 246 vs pH was sigmoidal with a pKa = 7.4 for both proteins with phosphate and sulfate. When synergistic anions were used with hTF/2N, malonate and oxalate gave pKas of ca. 6.9 and 7.1 for dependence of delta epsilon 246 on pH, but values of 7.3 and 7.6 for the H207E mutant protein. In an attempt to locate the anion binding site in hTF/2N, the binding of sulfate to the single point mutants of the N-lobe of human transferrin, K296E, K296Q, and K206Q, was carried out by difference UV spectroscopy at pH 7.4. In the case of K296E, sulfate binding gave delta epsilon 246 = 0, while for K296Q, it gave a slightly positive delta epsilon 246.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Diverse effects of the guanine nucleotide exchange factor RCC1 on RNA transport.

Transport of RNAs within nuclei and through nuclear pore complexes (NPCs) are essential, but poorly understood, steps in gene expression. In experiments with mammalian cells, RCC1, the abundant nuclear guanine nucleotide exchange factor for the guanosine triphosphatase Ran/TC4, was shown to be required for nucleocytoplasmic transport of precursors of spliceosomal small nuclear RNAs (snRNAs), intranuclear transport of U3 snRNA, and processing of ribosomal RNAs, but not for export of transfer RNAs. It is proposed that guanosine triphosphate (GTP)-bound Ran/TC4 associates with ribonucleoprotein particles (RNPs) during intranuclear movement, and that GTP hydrolysis promotes deposition of RNPs at targeted sites such as NPCs or nucleoli.

Biological Transport↗
PubMed1995

Infection rate of Ixodes ricinus ticks with Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi sensu stricto in Slovenia.

In spring 1993, Ixodes ricinus ticks were collected from six regions of Slovenia to determine their overall rate of infection with Borrelia burgdorferi sensu lato and to assess the frequency of individual species in these tick populations. Ticks were dissected and midgut tissue inoculated into modified Barbour-Stoenner-Kelly (BSK II) medium. Borrelia isolates were differentiated into separate species using species-specific polymerase chain reaction (PCR) primers and by large restriction fragment pattern (LRFP) analysis. Infected ticks were found in all six regions surveyed. Spirochaetes were isolated from 69 of 363 ticks (19%): the isolation rate from adult female ticks was 35% (23/66 ticks cultured), from adult male ticks 22% (20/91), and from nymphal ticks 13% (26/206). Determination of the species of 60 isolates revealed that 32 were Borrelia afzelii (53%), 20 were Borrelia garinii (33%), and 8 were Borrelia burgdorferi sensu stricto (13%). In the Ljubljana region Borrelia afzelii and Borrelia garinii predominated (43% and 40%, respectively), whereas Borrelia burgdorferi sensu stricto constituted only 17% of isolates. In three other regions of the country Borrelia afzelii was isolated exclusively, although the number of isolates investigated was small. This study demonstrates the presence of all three European species of Borrelia burgdorferi sensu lato within the Slovenian tick population and also within a geographic area of less than 100 m2.

Animals↗
PubMed1995

A long-lasting increase and decrease in synaptic excitability in the rat lateral septum are associated with high and low shuttle box performance, respectively.

In a series of experiments with rats, using evoked field potentials, the influence of massed trial training in 2-way shuttle box avoidance and step-through passive avoidance tasks was studied on the synaptic excitability of the lateral septum (LS) neurons and on the induction of long-term potentiation in the lateral septum in vivo. The majority of rats that attained a high performance level in the shuttle box task exhibited, after the shuttle box training, a long-lasting enhancement of synaptic excitability of lateral septum neurons, whereas most of the rats with low performance in the shuttle box showed a long-lasting depression in the LS synaptic excitability. Both types of excitability changes disappeared within 24 h. Neither the first habituation session in the passive avoidance apparatus nor the subsequent one-trial learning in passive avoidance task had a marked influence on lateral septum synaptic excitability. Both high-performance and low-performance rats exhibited a long-term potentiation (LTP)-like potentiation of synaptic excitability of the lateral septum neurons after high frequency stimulation of the fimbria fibers although the amount of LTP in high performance rats was slightly higher than that in low performance animals.

Animals↗
PubMed1995

Nucleotide and deduced amino acid sequences of the M and S genome segments of a Swedish Puumala virus isolate.

The Swedish Puumala (PUU) virus strain Vindeln 83-L20, isolated from a bank vole trapped in 1983 near Vindeln, Västerbotten county, Sweden, was characterized by nucleotide sequence analysis. The coding region of the M segment was determined by PCR followed by direct sequencing and the entire S segment was characterized by cloning and nucleotide sequence analysis. The genomic organization was found to be very similar to that of other PUU virus strains regarding open reading frames, polypeptide sizes and potential glycosylation sites. According to phylogenetic analysis 83-L20 was found to represent a new lineage within the Puumala virus serotype in the Hantavirus genus. The M segment sequence of 83-L20 was found to be more closely related to the Finnish PUU virus strains than to strains from Central Europe or from Russia. The evolutionary origin of the S segment was not as clearly resolved since the branching points of all PUU virus strains in the phylogenetic tree were nearly the same.

Amino Acid Sequence↗
PubMed1995

Genetic variation in Tula hantaviruses: sequence analysis of the S and M segments of strains from Central Europe.

Hantavirus carried by the European common vole Microtus arvalis from Moravia (Czech Republic) was analyzed by RT-PCR-sequencing and by reactivity with a panel of monoclonal antibodies (MAbs). Sequencing of the full-length S segment and the proximal part of the M segment showed that the virus belonged to genotype Tula (TUL) we discovered earlier in Microtus arvalis from Central Russia. This finding supported the concept of host dependence of hantaviruses. Phylogenetic analyses suggested a similar evolutionary history for S and M genes of TUL strains; thus far there is no evidence for reassortment in TUL. Geographic clustering of TUL genetic variants was observed and different levels of the genetic variability were revealed resembling those estimated for another hantavirus, Puumala (PUU). Comparison of the deduced N protein sequence from Russia and from Moravia showed that genetic drift in TUL occurred not only by accumulation of point mutations but also by the deletion of a nucleotide triplet. It encoded Ser252 which was located within a highly variable hydrophilic part of the N protein carrying B-cell epitopes and presumably forming a loop. Analysis of naturally expressed TUL N-antigen derived from lung tissue of infected voles with MAbs indicated antigenic heterogeneity among TUL strains.

Amino Acid Sequence↗
PubMed1995

Persistence of Borrelia burgdorferi sensu lato in resolved erythema migrans lesions.

Erythema migrans skin lesions resulting from a tick bite and infection with Borrelia burgdorferi sensu lato eventually resolve, even without antibiotic therapy. The aim of the present study was to gauge the frequency of persistence of B. burgdorferi sensu lato in such lesions. Thus, the site of a previous lesion was biopsied and cultured in 48 patients: 39 with systemic or localized symptoms/signs and nine with no symptoms. B. burgdorferi sensu lato was isolated from biopsied skin from three symptomatic patients. Cultures of other tissues and fluids were negative. By genospecies-specific polymerase chain reaction (PCR) and pulsed-field gel electrophoretic (PFGE) analysis, two isolates were classified as Borrelia afzelii. The remaining isolate was a member of an unusual group of strains that type as B. burgdorferi sensu stricto by genospecies PCR but possess an atypical PFGE profile. All three patients had a dramatic clinical response to antibiotic treatment. These findings demonstrate the capacity of viable B. burgdorferi sensu lato organisms to persist in clinically normal-appearing skin at the site of a resolved erythema migrans rash for periods ranging from 2 months to 3.5 years. This observation may provide new insight into the organisms' ability to evade the host's immune response.

Adolescent↗
PubMed1995

Genotypic and phenotypic characterization of Borrelia burgdorferi isolated from ticks and small animals in Illinois.

We have characterized 33 isolates of Borrelia burgdorferi from northern Illinois (32 isolates) and Wisconsin (1 isolate) representing the largest series of midwestern isolates investigated to date. The techniques used for molecular analysis of strains included (i) genospecies typing with species-specific PCR primers, (ii) plasmid profiling by pulsed-field gel electrophoresis of total genomic DNA, (iii) large-restriction-fragment pattern (LRFP) analysis by pulsed-field gel electrophoresis of MluI-digested genomic DNA (J. Belfaiza, D. Postic, E. Bellenger, G. Baranton, and I. Saint Girons, J. Clin. Microbiol. 31:2873-2877, 1993), (iv) sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total proteins, (v) microsequencing of high-performance liquid chromatography-purified peptides derived from proteins showing high levels of expression, (vi) amino acid composition analysis of proteins, and (vii) immunological analysis of proteins with a polyclonal antiserum of human origin. Five reference strains as well as two atypical tick isolates from California (DN127) and New York (25015) were included for comparison. All of the Illinois and Wisconsin isolates were typed as B. burgdorferi sensu stricto with genospecies-specific PCR primers. The isolates were found to be heterogeneous with regard to their plasmid and protein profiles. One isolate from Illinois possessed two large-molecular-size plasmids instead of the usual 49-kb plasmid. Fragment patterns resulting from MluI digestion of genomic DNA from the 33 isolates and strains DN127 and 25015 were separable into six distinct LRFPs, five of which have not previously been described. Strain 25015 and an isolate from Illinois (CT39) shared an unusual LRFP that is not typical of other B. burgdorferi sensu stricto strains, suggesting that they may represent a fifth species of B. burgdorferi sensu lato. Five of the 33 isolates and strains DN127 and 25015 showed high-level expression of proteins with molecular masses of approximately 22 kDa. Investigation of these proteins by microsequencing of individual peptides and total amino acid composition analysis indicated that the 22-kDa proteins expressed by the seven strains were polymorphic OspC proteins. By using a polyclonal serum of human origin, expression of OspC could be detected in all 33 Illinois and Wisconsin isolates.

Amino Acid Sequence↗
PubMed1995

[Sonographic diagnosis of ruptured corpus luteum with hemoperitoneum].

This article reports sonographic characteristics of a ruptured corpus luteum with hemoperitoneum in 44 cases. Sonographic findings were classified and compared with laparotomy and pathology. From sonographic imaging, it was found that the ruptured corpus luteum cyst was pathognomonic. There was a good correlation between ultrasound findings and surgical results when bleeding was over 100 ml. The sonographic value in diagnosis of ruptured corpus luteum with hemoperitoneum is discussed in detail.

Adult↗
PubMed1995

[Ultrasonic diagnosis of abnormalities of abdominal wall in fetuses].

Twelve cases of abnormal abdominal walls in fetuses are reported in this paper. Among them, there were 4 cases of umbilical hernia, 4 cases of a defective abdominal wall, 3 cases of diaphragmatic hernia and 1 case of a defective thoracic and abdominal wall. From the features of the sonographic picture, the reasons for misdiagnosis are discussed. From our analysis, the main points of differential diagnosis and the earliest time for making diagnosis are proposed. The diagnostic rate could be improved obviously by systemic and careful examination which is important for deciding the model and time of deliveries.

Abdominal Muscles↗
PubMed1995

[Percutaneous absorption of venenum bufonis in vitro].

V-C horizontal diffusion cell and HPLC determination have been used to study the effect of 1,2-propanediol and azone on the percutaneous absorption Venenum Bufonis. The contents of resibufogenin have been determined through mouse skin in vitro by HPLC. The results indicate that the contents get increased when 1,2-propanediol is added and that azone can shorten the lag time of percutaneous absorption of resibufogenin through mouse skin in vitro.

Amphibian Venoms↗