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Biomedical subjects

C Jin

Publications and source records attributed to C Jin.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain].

Based on the measurement above and below forest canopy and meteorological data, the spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain was analyzed. The results show that the photosynthetically active radiation(PAP) coefficients of total radiation, direct radiation and scatter radiation changed daily and yearly, with an annual averages of 0.46, 0.43 and 0.56 respectively. The average reflectivity, transmissitvity and absorptivity of single leaves of different tree species in Korean pine forest were 27.0%, 23.4%, 49.6% respectively. Single leaves nearly absorbed all of the ultraviolet radiation(UV) and 71.8% of photosynthetically active radiation, but transmitted 9.6% and reflected 18.6%. As for near-infrared radiation (NIR), the reflectivity and transmissitivity of leaves were a little less than the absorptivity. The forest canopy absorbed 93.9% PAR and 94.1% UV, but reflected and transmitted less. It absorbed 59.2%, reflected 26.3% and transmitted 14.4% NIR.

Light↗
PubMed2000

[Individual biomass of natural Pinus densiflora].

The aboveground biomass of individuals with different growth potentials in natural Pinus densiflora forest with different stand densities was measured in Yanbian, Jilin Province. The variation of individual biomass affected by densities was in order of dominant tree < intermediate tree < suppressed tree, while the distribution proportion of biomass in different organs affected by densities was: in order of trunk > branch > needle > bark. The biomass components of P. densifliora with different growth potentials varied markedly with the approaching of density class III, and the change of intermediate trees was similar to the whole stand. The vertical distributions of biomass of different trees were different from each other, but all showed that the biomass of trunks and barks was mainly distributed below 6 m high from ground, that of branches was within 6-10 m high, that of needles was uniform in the upper, middle and lower layers, and that of branches and needles in upper layer was least affected by density.

Biomass↗
PubMed2000

The role of membrane potential and calcium kinetic changes in the pathogenesis of vascular hyporeactivity during severe shock.

OBJECTIVE: To determine the role of membrane potential and intracellular calcium kinetic changes in producing vascular hyporeactivity during severe hemorrhagic shock. METHODS: Rats were subjected to hemorrhagic shock (HS) for 2 hours. The spinotrapezius muscle was prepared for microscopy and the responses of arterioles in the muscle to norepinephrine (NE) were tested. The resting membrane potentials of isolated arterial strips were measured with a microelectrode. Membrane potential and intracellular Ca2+ ([Ca2+]i) changes in isolated arteriolar smooth muscle cells (ASMCs) were determined with fluorescent probes and a confocal microscopy. RESULTS: The arteriolar resting membrane potential was decreased from -36.7 +/- 6.3 mV in control to -29.2 +/- 5.3 mV concurrent with the increase of vasoreactivity to NE at 20 minutes after HS. At 120 minutes post-HS, the resting potential hyperpolarized to -51.9 +/- 9.1 mV, and NE stimulated [Ca2+]i increase was reduced to 50% of the control values during the appearance of arteriolar hyporeactivity, i.e. the NE threshold of the arteriolar response increased 15 fold 2 hours after the onset of hemorrhage as compared with normal animals. The state of vasoreactivity was closely related to the resting potential of vascular smooth muscle in hemorrhagic shock, with a correlation coefficient of 0.96. Treatment with glybenclamide, a selective blocker of ATP-sensitive K+ (KATP) channels, decreased the resting potential, increased NE-stimulated [Ca2+]i increase, and partially restored vasoreactivity in severe hemorrhagic shock. CONCLUSION: The results suggested that membrane hyperpolarization and the reduction of NE-stimulated [Ca2+]i increase in smooth muscle cells appeared to contribute to the vascular hyporeactivity in hemorrhagic shock. The mechanism is likely to involve in KATP channels.

Animals↗
PubMed2000

Biological function of a novel gene overexpressed in human hepatocellular carcinoma.

OBJECTIVE: To clone the full-length of a differentially expressed cDNA fragment, LC27, and study its biological function tentatively. METHODS: Northern blot was used to analyze the expression pattern of LC27 in hepatocellular carcinoma, matched nontumor liver tissues, fetal liver and normal adult liver tissues, as well as BEL-7402 hepatocellular carcinoma cell line ESTs splicing and 5' rapid amplification of cDNA ends (5' RACE) were used to clone the full-length of LC27 cDNA. An antisense oligodeoxynucleotide approach was used to investigate the biological role of the gene in the proliferation of BEL-7402 cells. RESULTS: A 2186 bp novel cDNA with an open reading frame encoding a 283 amino acid protein was cloned. Analysis of the deduced amino acid sequence indicated that it is 38% (88/229) identical to human Golgi 4-transmembrane spanning transporter MTP. The gene and the encoded protein was termed hepatocellular carcinoma overexpressed transmembrane protein (hotp) and HOTP, respectively. Hotp mRNA was almost undetectable in normal adult liver and fetal liver tissues. However, it was significantly up-regulated in hepatocellular carcinoma and some matched nontumor liver tissues, as well as BEL-7402 cells. The proliferation of BEL-7402 cells was suppressed by an antisense oligodeoxynucleotide against hotp mRNA at a concentration of 50 micrograms/ml. CONCLUSION: HOTP may be an integral membrane transporter protein. The overexpression of the gene in hepatocellular carcinoma may play an important role in hepatocarcinogenesis and disease progression.

Adult↗
PubMed2000

[The effects of electroporation-mediated erythropoietin (EPO) gene transfer into skeleton muscle on renal anemia].

OBJECTIVE: To investigate the effects of erythropoietin (EPO) gene transfer into skeleton muscle mediated by electroporation on renal anemia. METHODS: Renal failure models were created by adenine-excessive diet (150 mg per day). Plasmid vectors encoding EPO were transferred by electroporation after 80 days when mean blood urea nitrogen level (BUN) had increased from 3.4 mmol/L +/- 1.3 mmol/L to 18.1 mmol/L +/- 4.1 mmol/L and the hematocrit had decreased from 45.6% +/- 2.1% to 25.4% +/- 3.7%. During the process of treatment, adenine-excessive diet was given. Hb, HCT, BUN and Cre in blood were tested by automatic analyzer; EPO level in the serum was tested by EPO ELISA kit, EPO gene expression was proved by RT/PCR. The survival rate was calculated. RESULTS: Hematocrit increased to 34.4% +/- 7.5% only 7 days after the treatment and reached 91.4% of normal level (46% +/- 2%) after 5 weeks. The survival rate of test models after 9 weeks was 77.8%, which was remarkably higher than that of controls (16.7%). mRNA level of EPO gene expression was indicated by RT/PCR. CONCLUSION: Electroporation can increase the efficiency of EPO gene transfer and thus greatly improve hematocrit in mice and prolong the life-span of chronic renal anemia models. This method can provide a new way for treatment of EPO-responsive anemias.

Adenine↗
PubMed2000

[The effect of methylenum coeruleum in laparoscope cholecystectomy].

OBJECTIVES: To help the operator correctly judge in operation the cystic gall duct and choledoch, and eliminate the operation wound. METHODS: To divide laparoscope cholecystectomy patients with the same weight at the same period into two groups: development group (589 cases) using methylenum coeruleum and conducting cholecysto-puncture visualization during the operation in which colors of cholecyst, cystic gall duct and choledoch turn blue; comparative group (553 cases) using regular laparoscope cholecystectomy. RESULTS: The two groups differed remarkably in operation time, complication, and transferring rate (P < 0.01). CONCLUSIONS: Methylenum coeruleum development technology in operation is a kind of visualization to help the operator judge in operation Calot triangular anatomy construction correctly, reduce the operation time obviously, and increase the rate of success.

Adult↗
PubMed2000

[Cloning and expression of the gene encoding maltoologosyl trehalose synthase from Sulfolobus shibatae in E. coli].

2.2 kb DNA fragment encoding a novel enzyme, maltooligosyl trehalose synthase (MTSase) was amplified from Sulfolobus shibatae by using PCR technique. The amplified 2.2 kb DNA fragment was inserted into an expression vector, pBV220, to yield the recombinant plasmid pSBGT1. MTSase gene in pBSGT1 was expressed in E. coli. The molecular weight of expressed MTSase detected by SDS-PAGE was about 74 kD, which is conformed with that deduced from nucleotide sequence. The expressed MTSase protein accounted for about 4.4% of the total cell protein. The MTSase from transformants containing pBSGT1 is capable of decreasing DE value, forming non-reducing or less-reducing saccharides when allowed to act on reducing partial starch hydrolysates.

Cloning, Molecular↗
PubMed2000

[Cloning and expression of the gene encoding novel alpha-amylase from Sulfolobus shibatae in E. coli].

A novel alpha-amylase gene was amplified from Sulfolobus shibatae by using PCR technique. The amplified 1.7 kb DNA fragment was inserted into an expression vector pBV220 to yield the recombinant plasmid pSBAM. The novel alpha-amylase gene in pSBAM was expressed in E. coli. The production of the novel alpha-amylase activity reached over 8 units/100 mL of the culture. The molecular weight of this enzyme was about 61 kD by SDS-PAGE. The expressed novel alpha-amylase protein in E. coli DH5 alpha accounted for about 20% of the total protein in the recombinant cell. The cooperative action of the novel alpha-amylase and the maltooligosyltrehalose synthase from Sulfolobus shibatae was investigated and trehalose was detected by using HPLC analysis when using amylose and partial starch hydrolysates as substrates.

Cloning, Molecular↗
PubMed2000

[The multicolour three-photon resonant ionization spectrum studies in uranium atom].

The multicolour three-photon resonant ionization spectra of 238U were measured by using the pulsed dye lasers system synchronously pumped by a frequency doubled Nd:YAG-laser 532 nm output(operated at 10 Hz), a device for atomic beam of U, time-of-flight mass spectrometer and boxcar integrator. The dye laser pulses have a 6 ns duration. Beams from the dye lasers, which have the same polarization direction and are focused by lenses, entered an interaction chamber through opposite windows on a common axis and spatially overlapped the U atomic beam. The optical pulse from dye laser DL2 was delayed to arrive at the interaction region 8 ns after the pulse from dye laser DL1; in the same way, the pulse from DL3 was delayed 8 ns after from DL2. The atomic beam device was made from stainless steel. We generated the U vapor by heating solid U in a graphite crucible by e-type electron-field on first excited states were studied in uranium atom. The question how to determine single-colour, two-colour and three-colour three-photon resonant ionization peak in the three-colour three-photon resonant ionization spectra diagram were solved.

English Abstract↗
PubMed2000

[Identification of high-lying odd energy levels of uranium by resonant ionization mass spectrometry].

Single-colour and two-colour multiphoton resonant ionization spectra of uranium atom were studied extensively with a Nd:YAG laser-pumped dye laser atomic beam apparatus time-of-flight mass spectrometer in our laboratory. The energy locations of high-lying odd-parity levels in the region 33,003-34,264 cm-1, measured by a two-colour three-step ionization technique, were reported here. The angular momentum quantum number J was uniquely assigned for these levels by using angular momentum selection rules.

Lasers↗
PubMed1999

Low convulsive activity of a new carbapenem antibiotic, DK-35C, as compared with existing congeners.

Since carbapenems and cephalosporins have been suggested to induce convulsive side effects through an inhibitory action on the central gamma-aminobutyric acid (GABA)-mediated inhibitory transmission, the present study evaluated the convulsive activity of a new carbapenem antibiotic (1R,5S,6S)-6[(R)-1-hydroxyethyl]-2-[(3S,5S)-5(S-methyl-4thiomorpholin ylcarbonyl)pyrrolidin-3-thio]-l-methylcarbapen-2-em-3- carboxylic acid (DK-35C) in in vitro and in vivo experiments, in comparison with cefazolin, imipenem and meropenem. In in vitro experiments, their abilities to inhibit [3H]muscimol (5 nM) binding to GABA(A) receptors were measured using crude synaptic membranes prepared from the rat cerebral cortex. The concentrations (mM) of the antibiotics which inhibit 50% of the specific binding, were 0.6 for imipenem, 1.8 for cefazolin, 15.4 for DK-35C and 27.6 for meropenem. In in vivo experiments, intracerebroventricular (i.c.v.) injections of cefazolin, imipenem and DK-35C induced convulsions in a dose-dependent manner in rats. The doses (nmol/rat) of the antibiotics which induce convulsions in 50% of rats, were 57 for imipenem, 96 for cefazolin, 377 for DK-35C and >3000 for meropenem. In the mouse pentylenetetrazole (PTZ) convulsive model, intravenous pretreatment with cefazolin (800 mg/kg) or imipenem (200 mg/kg) shifted the dose-response curve of PTZ (i.p.) to the left, indicating enhancement of the convulsive activity of PTZ. However, pretreatment with cefazolin, meropenem or DK-35C at a dose of 400 mg/kg did not produce any marked effects on the convulsive activity of PTZ compared with the saline vehicle-pretreated control. The results clearly demonstrate a good correlation between in vitro GABA(A) receptor binding assay and in vivo i.c.v. convulsive model using rats, and suggest that DK-35C may possess a relatively weak convulsive activity mediated through an interaction with GABA(A) receptors.

Animals↗
PubMed1999

Stage-specific expression of alpha1,2-fucosyltransferase and alpha1, 3-fucosyltransferase (FT) during mouse embryogenesis.

Lex [Galbeta1-4(Fucalpha1-3)GlcNAc] and Ley [Fucalpha1-2Galbeta1-4(Fucalpha1-3)GlcNAc] are both stage-specific embryonic antigens. Lex is first detected on the blastomeres of the 8-cell stage embryo, which correlates with the onset of blastomere compaction. Ley is highly expressed on the surface of the blastocyst, which has been shown to be involved in blastocyst attachment in the mouse. In the present study, mouse alpha1,2-FT (also known as FUT1) and alpha1,3-FT (also known as Fuc-TIV), which were responsible for Lex and Ley formation, were examined in preimplantation stage embryos by reverse transcription-PCR and in situ hybridization. alpha1,3-FT mRNA was detected in all embryos of preimplantation stage, while alpha1,2-FT mRNA emerged in the later stage embryos from 8-cell to 16-cell to the blastocyst. These results indicated the expression of Ley was regulated by alpha1,2-FT. In situ hybridization showed that these two enzyme mRNAs were detected only in morula and blastocyst stage embryos. The alpha1,2-FT and alpha1, 3-FT mRNAs were located in both the inner cell mass and the trophoblast cells. 2-Cell and 4-cell embryos were isolated from the oviduct and cultured in vitro to the 8-cell, morula and blastocyst stage. The expression of alpha1,2-FT and alpha1,3-FT were observed in these embryos developed in vitro; immunohistochemical analysis also showed that Ley expression was positive. These results suggested the stage-specific expression of Ley on the embryos was synthesized by endogenous alpha1,2-FT and alpha1,3-FT rather than transfer from other sources. In addition, the expression of alpha1, 2-FT was differentially regulated and the uterine factor was not prerequisite of the expression of Ley.

Animals↗
PubMed1999

Backbone dynamics of a winged helix protein and its DNA complex at different temperatures: changes of internal motions in genesis upon binding to DNA.

The dynamic properties of a winged helix protein, Genesis, and its DNA complex at different temperatures were studied. Due to the complexity of motions, the commonly used model-free formalism could not be used to reflect the dynamic properties. The reduced spectral density function mapping approach was proven to be a useful tool to describe the overall and internal motion of molecules on the picosecond to nanosecond time-scale, and conformational exchanges on the microsecond to millisecond time-scale. The local motions in DNA-free Genesis showed strong temperature dependence and the backbone dynamics of each secondary structural element responds to the temperature change differently, while the Genesis-DNA complex showed more stability with changing the temperatures. Furthermore, each DNA contact sequence of Genesis showed distinct dynamic perturbation after Genesis binds to DNA.

DNA↗
PubMed1999

Dynamic DNA contacts observed in the NMR structure of winged helix protein-DNA complex.

Genesis is an HNF-3/fkh homologous protein. By using multi-dimensional NMR techniques, we have obtained the solution structure and backbone dynamics of Genesis complexed with a 17 base-pair DNA. Our results indicate that both the local folding and dynamic properties of Genesis are perturbed when it binds to the DNA site. Our data show that a conserved flexible amino acid sequence (wing 1) makes dynamic contacts to DNA in the complex and a short helix is induced by Genesis-DNA interactions. Our data indicate that, unlike the HNF-3gamma/DNA complex, a magnesium ion is not required in forming the stable Genesis-DNA complex.

Amino Acid Sequence↗
PubMed1999

The binding interface between an E2 (UBC9) and a ubiquitin homologue (UBL1).

Human UBC9 is a member of the E2 (ubiquitin conjugation enzyme) family of proteins. Instead of conjugating to ubiquitin, it conjugates with a ubiquitin homologue UBL1 (also known as SUMO-1, GMP1, SMTP3, PIC1, and sentrin). UBC9 has been shown to be involved in cell cycle regulation, DNA repair, and p53-dependent processes. The binding interfaces of the UBC9 and UBL1 complex have been determined by chemical shift perturbation using nuclear magnetic resonance spectroscopy. The binding site of UBL1 resides on the ubiquitin domain, and the binding site of UBC9 is located on a structurally conserved region of E2. Because the UBC9-UBL1 system shares many similarities with the ubiquitin system in structures and in conjugation with each other and with target proteins, the observed binding interfaces may be conserved in E2-ubiquitin interactions in general.

Humans↗
PubMed1999

Nonrandom karyotypic features in squamous cell carcinomas of the skin.

We report the finding of clonal chromosome abnormalities in 13 short-term cultured squamous cell carcinomas (SCCs) of the skin. Intratumor heterogeneity, in the form of cytogenetically related (subclones) or unrelated clones, was detected in six tumors. Whereas clones with complex karyotypic changes were found in 6 tumors, clones with simple anomalies were observed in 10 tumors, and sometimes these clones coexisted with highly abnormal clones. Rearrangement of chromosome 8, in the form of isochromosome i(8q) or whole arm translocation, was the most common aberration, found predominantly in complex clones. Another recurrent feature, i.e., the centromeric rearrangement of chromosome 1, as isochromosome i(1q) or i(1p), or whole arm translocations, was always part of a complex karyotype. Homogeneously staining regions were found in two cases, one with a highly complex karyotype and the other with a simple karyotype. In order to obtain an overall karyotypic picture in SCC of the skin, the cytogenetic findings in 10 SCCs reported earlier were reviewed. The chromosomes most commonly affected were, in decreasing order, chromosomes 1, 11, 8, 9, 5, 3, and 7. Chromosomal sites most frequently rearranged were almost all pericentromeric: they were 8q10-q11, 1p10-q12, 5p10-q11, 11p15, and 9p10-q10. Recurrent anomalies were i(1q), i(8q), i(5p), i(1p), i(9p), and i(9q). Among them, only i(8q) and i(9q) might be assumed to be early genetic events, considering the fact that they could occasionally be identified in simple clones. The most frequent losses included part of or the entire chromosomes 2, 4, 9, 11, 14, 18, and 21, arm 8p, and chromosomes X, Y, and 13. Overrepresentation most frequently involved 1q, chromosome 7, and 8q. The characteristic karyotypic pattern observed in skin SCC was in line with the experience in several other carcinomas. Genes Chromosomes Cancer 26:295-303, 1999.

Aged↗
PubMed1999

Identification of IY81149 and its metabolites in the rat plasma using the on-line HPLC/ESI mass spectrometry.

Reversed-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) with an electrospray ionization (ESI) interface was applied to the identification of metabolites of IY 81149 in the rat plasma. Fragments obtained using collision-induced dissociation (CID) in both positive and negative modes were utilized to elucidate the structure of metabolites. The eluent from the conventional HPLC column was split and directly introduced into an ESI-mass spectrometer for the identification of the structures. The CID technique allowed the sensitive identification of sulfonyl-IY81149 and hydroxy-IY81149 from the rat plasma.

2-Pyridinylmethylsulfinylbenzimidazoles↗