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Biomedical subjects

S Han

Publications and source records attributed to S Han.

At least 109 records · Page 6Linked to original sources
PubMed2001

Three-dimensional Z-plasty in the correction of the unilateral cleft lip nasal deformity.

OBJECTIVE: Numerous methods have been introduced for correction of the cleft lip nasal deformities, but no single procedure has given sufficiently satisfactory results to provide a surgical standard. Much effort has been put on restoring cartilaginous structures using alar cartilage modification and suspension. But even after the cartilage framework is repositioned well, redundant alar webbing is still unsightly and frequently conspicuous. This paper presents a procedure combining the usual open rhinoplasty technique and three-dimensional Z-plasty in an external approach to remove the alar web and to lengthen the columella at the same time. METHODS: Open rhinoplasty was performed in 26 consecutive patients with unilateral cleft lip nasal deformity from 1991 to 1996. We used an open rhinoplasty approach, which is a combination of the usual infracartilaginous incision on the noncleft side and a small triangular flap on the cleft side. RESULTS AND CONCLUSIONS: This external rhinoplasty incision can provide a wide surgical field for the handling of the whole cartilage framework. The three-dimensional Z-plasty utilizing redundant alar skin not only removes the alar web but also helps lengthen the columella and provides soft tissue to the nasal vestibule. This technique is easy, and the postoperative result is very consistent. Our open rhinoplasty approach has several advantages and can be a useful approach in the correction of the unilateral cleft lip nasal deformity.

Adolescent↗
PubMed2001

Quantitative structure-activity relationships: comparative inhibition of nitrogen-containing aromatics on germination of Cucumis sativus.

Comparative inhibition effect of selected nitrogen-containing aromatics on germination rate of Cucumis sativus was investigated, and quantitative structure-activity relationships were developed and mechanistically interpreted. Energy of lowest unoccupied orbital was found to successfully model the toxicity of the test chemicals. It was discovered that inhibition of nitrogen-containing aromatics to germination of Cucumis sativus was caused mainly by their in vivo redox reaction.

Aminopyridines↗
PubMed2001

Application of time-of-flight secondary ion mass spectrometry to automobile paint analysis.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides a method of elemental analysis that can distinguish among automotive paint samples of the same or nearly the same color. TOF-SIMS survey spectra were employed to determine the relative abundances of elements in the surface layers of the paint chips. The depth profile of paint samples permitted the analysis of small paint chips, the reproducible results for specific elements, and the identification of each car paint. Seventy-three samples of blue, red, white, and silver automobile paints from the major manufacturers in Korea were investigated using high resolution TOF-SIMS technique. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. TOF-SIMS is a reliable, nondestructive, and small area analyzing method for characterization of the elemental composition of automotive paint chips.

Journal Article↗
PubMed2001

[Diagnosis and surgical treatment of peripheral intrahepatic cholangiocarcinoma].

OBJECTIVE: To summarize the experience in diagnosis and surgical treatment of peripheral intrahepatic cholangiocarcinoma (PICC). METHODS: Clinicopathological features, surgical treatment and prognosis of 20 patients with PICC treated in our hospital from 1970 to 1999 were retrospectively analyzed. RESULTS: The patients lacked typical clinical manifestations and some had a history of hepatitis B (35%), cirrhosis (45%), and elevation of serum alpha-fetaprotein (AFP) (25%). The diagnostic rates of ultrasound examination (BUS), CT, MRI and emission computerized tomography (ECT) were 90% (18/20), 94% (17/18), 100% (3/3) and 100% (4/4), respectively. However, the liver lesions detected by these methods needed to be differentiated from hepatocellular carcinoma (HCC), metastatic neoplasm and liver cyst, etc. In all the patients, the resection rate was 60% (12/20) and postoperative overall 1-, 3- and 5-year survival rates were 55% (11/20), 35% (7/12) and 20% (4/20), respectively. The liver resection rates were 83% (11/12), 58% (7/12) and 33% (4/12), respectively. Of the 4 patients who had survived for more than 5 years, 3 had a small liver carcinoma with a diameter less than or equal to 3 cm and one had large nodular liver carcinoma with intact capsule. After operation, all the patients received selective hepatic artery perfusion chemotherapy. CONCLUSION: PICC patients lack specific serum tumor marker can achieve good survival after early detection and curative resection with adjuvant therapies.

Adult↗
PubMed2001

[Tree stomatal infiltration and SO2 injury and protection effect of ABA].

This paper deals with relation between tree stomatal infiltration and SO2 injury and the protection effect of ABA. Experiments of SO2 smoking to the selected trees were carried out and the data were collected in the field. The results show that stomatal infiltration was a comparably constant index for certain tree species. The infiltration of trees is negatively correlated with the combine extent of chlorophy, but not obviously. The index is also positively correlated with K+ efflux in leaf(r = 0.92, alpha < 0.01). In the experiment of SO2 smoking, the effect on infiltration of same species under different SO2 concentration was little, less than one grade, while K+ efflux increased with the increment of SO2 amount absorbed by the leaves. When the leaves were sprayed with ABA solution, the higher the ABA solution concentration was, the lower the K+ efflux was. When leaves sprayed with ABA solution were smoked with 2.5 mol.L-1 for four hours, the infiltration of leaves with 30 mol.L-1 ABA solution dropped 1.5-3 and K+ concentration decreased 36.5%-54.8% on leaves. It indicates that the ABA solution on leaves has remarkable effect of protection of SO2 injury.

Abscisic Acid↗
PubMed2001

[N2O emission by trees under natural condition].

The sources of N2O, one of the major greenhouse gases in the atmosphere, are still unclear till now. It was previously thought that only soil microbial process produced N2O. The aim of this study was to provide evidences that plant can emit N2O under the natural condition. The measurement of aboveground vertical profiles of N2O concentrations were conducted within coniferous-deciduous mixed forests in Changbai Mountain, China. Significant high N2O concentrations were found at or near the height of canopy. High concentrations in profiles were 3.03% to 64.9% higher than the "normal concentrations". Differences between the high concentrations and the "normal concentrations" were statistically significant. The simultaneous occurrence of high concentrations at/nearby the canopy height and normal concentrations at the trunk space height indicated an efflux of N2O from foliage to atmosphere. This study afforded evidences supporting that plant per se, besides forest soil, was an important source of atmospheric N2O in a forest ecosystem.

Air↗
PubMed2001

[Analysis of environmental gradient and community of forest-swamp ecotone in Changbai mountains].

This paper discussed the change pattern between environmental gradients and community structure, productivity and plant diversity of forest-swamp ecotones, and the mechanism forming those community's traits, which could supply a theoretical basis for conserving and managing the biological resources of ecotonal communities. By setting up sample belts along the environmental gradients on three kinds of ecotones between forests and swamps in Changbai Mountains and through investigating initial data and establishing regression models, the authors studied the dynamic pattern of species composition, diameter class and age class of dominant species, plant diversity, community productivity of forest-swamp ecotone communities with environmental gradients. The results showed that the distribution patterns of community structure characteristics, plant diversity and community productivity were consistent with the changes of environmental gradients of forest-swamp ecotones. Along the environmental gradient from swamp to forest, the displace of dominant species happened, and the species number increased by positive exponent. The diameter distribution of trees decreased by inverse curve, and the age class of trees was suited to cubic distribution. The plant diversity increased by quadratic, and the community biomass increased by cubic power curve along the environmental gradients. The above-mentioned results suggested that the relationships between communities and environmental gradients were closely related.

China↗
PubMed2001

[Ecophysiological response of Pinus koraiensis seedlings to elevated CO2].

Studies on the ecophysiological response of Pinus koraiensis seedlings were conducted in open-top chambers which were controlled with CO2 concentration of about 500 and 700 mumol.mol-1. The result shows that there were different responses in net photosynthetic rate and stomatal conductance at high CO2(500 and 700 mumol.mol-1) and ambient CO2 concentrations. Under 500 mumol.mol-1 CO2, the carboxylase activity of RuBP was the highest, the photosynthesis showed "up-ward", the average daily net CO2 assimilation was the greatest, and the contents of chlorophyll and soluble sugars were the highest. While under 700 mumol.mol-1 CO2, the photosynthesis showed "down-ward" and was lower than that of the control, and the enzyme activity and the contents of substances were the lowest.

Carbohydrate Metabolism↗
PubMed2001

[Clinical analysis of 149 cases of aldosterone-producing adrenal cortical neoplasms].

OBJECTIVE: To evaluate the diagnosis and treatment of aldosterone-producing adrenal cortical neoplasms. METHODS: From 1978 to February 2001, 149 patients with aldosterone-producing adrenal cortical neoplasms were diagnosed and treated. Of these patients, 148 had adrenal adenoma and 1 had adrenal cortical carcinoma. The diagnosis was all confirmed by surgery and pathological studies. RESULTS: The diagnostic specificity of retroperitoneal pneumography, B-ultrasonography and CT scan are 39%, 67% and 95.3% respectively. It was found that there were significant differences of diagnostic specificity between retroperitoneal pneumography and B-ultrasonography, CT scan (chi2 = 23.89, P < 0.05) and there were significant differences between B-ultrasonography and CT scan (chi2 = 32.10, P < 0.05). In all the patients, serum potassium level elevated to normal range within 1 month postoperatively. In 110 cases out of 149, the blood pressure dropped to normal range within two months after surgery. CONCLUSIONS: Appropriate treatment depends on correct qualitative diagnosis and localization of the causative lesion. B-ultrasonography and CT scan play an important role in diagnosis. Surgery is the major treatment, including laparoscopic adrenalectomy. Factors affecting the therapeutic outcome are aging systemic vascular sclerosis and long duration of the disease.

Adrenal Cortex Neoplasms↗
PubMed2000

Oligonucleotide-capped gold nanoparticles for improved atomic force microscopic imaging and enhanced selectivity in polynucleotide detection.

A novel assay for selective determination of polynucleotides using atomic force microscopy in conjunction with the formation of the probe/target/DNA-gold nanoparticle sandwich structure at a gold surface is described. A 17-mer probe was attached to the surface for subsequent hybridization with a polynucleotide target. Due to the flat orientation of the probe-target hybrid with respect to the surface and the spatial obstruction of the unhybridized probes near the hybrids, the AFM images are not clear. The hybridization efficiency was estimated to be about 1.1% since certain surface features could not be resolved. The utilization of 30-mer-capped gold nanoparticles not only provides another dimension of selectivity, but also reorients the previously formed probe-target hybrid in such a way that the strands of the target become tethered with respect to the surface. This reorientation improves the resolution in imaging the hybridized target molecules and provides an accurate determination of the hybridization efficiency (16%).

Base Sequence↗
PubMed2000

Degree of apoptosis induced by adenovirus-mediated transduction of p53 or p73alpha depends on the p53 status of glioma cells.

It has been reported that U-87MG glioma cells with wild-type p53 are resistant to p53 replacement gene therapy. As some gliomas harbor wild-type p53, it would be important to override the resistance mechanism due to wild-type p53 in glioma gene therapy. In this study, we transduced U-87MG cells or U251 glioma cells harboring mutated p53 with the p53 or p73alpha gene (a homologue of p53, that differently induces some p53-responsive genes) via adenovirus vectors (Advs) at same multiplicities of infection (MOIs) into respective cells (U-87MG: MOI 1000, U251: MOI 100), and evaluated the degree of apoptosis. The results demonstrate that the degree of apoptosis induced by Adv-mediated transduction of p53 in U-87MG cells was lower than that in U251 cells, whereas that induced by Adv-mediated transduction of p73alpha in U-87MG cells was higher than that in U251 cells. Bax expression in U-87MG and U251 cells induced by Adv-mediated transduction of p53 was almost the same as that of p73alpha. On the other hand, Adv-mediated transduction of p73alpha induced caspase-9 at higher levels than that of p53 in both cells. The results indicate that Adv-mediated transduction of p73alpha might be beneficial to overcome the resistance mechanism of glioma cells harboring wild-type p53.

Adenoviridae↗
PubMed2000

Interactions between spatial attention and global/local feature selection: an ERP study.

The present study examined the interaction between spatial attention and global/local feature processing of visual hierarchical stimuli. Event-related brain potentials (ERPs) were recorded from subjects who detected global or local targets at attended locations while ignoring those at unattended locations. Spatial attention produced enhanced occipital P1 and N1 waves in both global and local conditions. Selection of local features enhanced posterior P1, N1 and N2 waves relative to selection of global features. However, the modulations of the P1 and N2 by global/local feature selection were stronger when spatial attention was directed to the left than the right visual fields. The results suggest neurophysiological bases for interactions between spatial attention and hierarchical analysis at multiple stages of visual processing.

Adult↗
PubMed2000

Nitric oxide protects Cu,Zn-superoxide dismutase from hydrogen peroxide-induced inactivation.

Reaction of Cu,Zn-superoxide dismutase (SOD1) and hydrogen peroxide generates a putative oxidant SOD-Cu2+-.OH that can inactivate the enzyme and oxidize 5,5'-dimethyl-1-pyrroline-N-oxide (DMPO) to DMPO-.OH. In the presence of nitric oxide (.NO), the SOD1/H2O2 system is known to produce peroxynitrite (ONOO-). In contrast to the proposed cytotoxicity of .NO conferred by ONOO-, we report here a protective role of .NO in the H2O2-induced inactivation of SODI. In a dose-dependent manner, .NO suppressed formation of DMPO-.OH and inactivation of the enzyme. Fragmentation of the enzyme was not affected by .NO. Bicarbonate retarded formation of ONOO-, suggesting that .NO competes with bicarbonate for the oxidant SOD-Cu2+-.OH. We propose that .NO protects SOD1 from H2O2-induced inactivation by reducing SOD-Cu2+.OH to the active SOD-Cu2+ with concomitant production of NO+ which reacts with H2O2 to give ONOO-.

Animals↗
PubMed2000

Differential inhibition of the human cell DNA replication complex-associated DNA polymerases by the antimetabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP).

The antimetabolite 1-beta-D-arabinofuranosylcytosine (ara-C) has been used as a highly effective agent for the treatment of leukemia. The active metabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP) is a potent inhibitor of DNA polymerases alpha, delta, and epsilon, and is responsible for inhibiting intact cell DNA synthesis. We have shown that a multiprotein complex, exhibiting many of the properties expected of the human cell DNA replication apparatus, can be readily isolated from human cells and tissues and is capable of supporting origin-dependent DNA synthesis in vitro. DNA polymerases alpha, delta, and epsilon are components of this multiprotein complex, termed the DNA synthesome, and we report here that the activities of these DNA synthesome-associated DNA polymerases are inhibited differentially by ara-CTP. Inhibition of the DNA synthesome-associated DNA polymerase alpha increased in a concentration-dependent manner, and was correlated closely with the inhibition of simian virus 40 (SV40) origin-dependent in vitro DNA replication, whereas DNA synthesome-associated DNA polymerase delta activity was not inhibited significantly by ara-CTP at 100 microM. Recent work has shown that the synthesome-associated DNA polymerase epsilon does not function in in vitro SV40 DNA replication, suggesting that only polymerases alpha and delta drive the DNA replication fork. Therefore, our results suggest that inhibition of the activity of the mammalian cell DNA synthesome by ara-CTP is due primarily to the inhibition of the DNA synthesome-associated DNA polymerase alpha. This observation implies that the drug may target specific phases of the DNA synthetic process in human cells.

Arabinofuranosylcytosine Triphosphate↗
PubMed2000

Protective effect of etomidate on kainic acid-induced neurotoxicity in rat hippocampus.

The goal of this study was to determine whether etomidate has protective effect against kainic acid (KA)-induced neurotoxicity. Administration of etomidate (20 mg/kg i.p.) was performed in sequence, first being just 1 h after KA (10 mg/kg i.p.) injection, then three times at 1-h intervals. Neuronal damages in hippocampus were evaluated by using the acid fuchsin stain to detect cell death and the heat shock protein-70 (HSP-70) induction as an index of cell injury at 24 h after the administration of KA. HSP-70 induction and acid fuchsin positive neurons were increased in CA1 and CA3 regions of hippocampus after KA injection but significantly decreased by etomidate-injection. These results suggest that the etomidate hold potential effect on the protection of neurons against KA-induced neurotoxicity.

Animals↗
PubMed2000

Father-son testicular tumors: evidence for genetic anticipation? A case report and review of the literature.

BACKGROUND: The etiology of testicular carcinomas is unknown. Father-son testicular tumors represent an important subset of patients because the sons have a 6- to 10-fold increase in the risk of developing a testicular tumor compared with the general population, suggesting a possible genetic component in the etiology of the disease. Genetic anticipation has been established for several diseases and manifests itself clinically with earlier age of onset (AO) of disease or with increased severity of disease in children compared with their parents. METHODS: We report only the 13th case of pure seminoma occurring in both a father and a son. The most striking feature of our case study was a 27-year difference in the AO between father and son. A review of the literature from 1972 through 1999 provided 47 cases of father-son testicular tumors in which sufficient information was available to compare the AO and the severity of the disease in the fathers (G1) and the sons (G2). RESULTS: The mean AO for G1 was 43.3 (+/- 1.6) years compared with a mean AO for G2 of 27.0 (+/- 1.0) years for all 47 cases (P < 0.01). For fathers presenting with a pure seminoma, the mean AO was 45.9 (+/- 1.8) years for G1 compared with 27.0 (+/- 1.1) years for G2 (P < 0.01). For fathers presenting with a nonseminomatous tumor, the mean AO in G1 was 37.9 (+/- 2.6) years and 26.9 (+/- 1.8) years for G2 (P < 0.01). For the entire group of 47 cases, disease was more severe in G2 compared with G1 in 43% of cases, of equal severity in 47% of cases, and less severe in G2 compared with G1 in 10% of cases. CONCLUSIONS: Genetic anticipation may be responsible for many father-son testicular tumors.

Adolescent↗