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Biomedical subjects

S Chen

Publications and source records attributed to S Chen.

At least 487 records · Page 27Linked to original sources
PubMed2000

[Preliminary study on relationship between antibody against heat stress protein 70 and hypertension].

OBJECTIVE: To preliminarily explore the relationship between main antibody against heat stress protein 70 (anti-HSP70) and hypertension. METHODS: Serum anti-HSP70 was determined with Western blotting technique in hypertensive and normotensive groups. Logistic regression model was used to analyze the relationship between anti-HSP70 and hypertension. RESULTS: It was found that level of antibody against the main heat shock protein 70 was significantly higher in patients with hypertension (based on criteria of 160/95 mm Hg, 1 mm Hg = 0.133 kPa) than in controls, after adjustment for the generally recognized risk factors for hypertension (such as age, sex, length of employment, body mass index, job, et al.). There still was stronger association between anti-HSP70 and hypertension (based on criteria of 140/90 mm Hg), but its strength of association was weaker than the former. CONCLUSIONS: Anti-HSP70 may potentially serve as a serum biomarker to assess hypertension, or anti-HSP70 itself may be involved in the development of hypertension.

Autoantibodies↗
PubMed2000

[Studies on human streptococcal infectious syndrome caused by infected pigs].

OBJECTIVES: To demonstrate the clinical manifestations of S. suis infectious syndrome; to study the characteristics of causative organism and its source. METHODS: 25 cases of unknown causes of food poisoning were identified in the central area of Jiangsu province, China in July 1998. Biological specimens was collected in some patients, and the causative organism was isolated using a number of different culture medium. Isolated organisms were identified by serum antibody tests, API biochemical tests, drug sensitivity tests and animal model experiments. The human born strains and the pig born strains were compared by RAPD technique. Epidemiological methods were applied to trace the source of causative organisms. RESULTS: Cases were clinically categorized into two types: Streptococcal toxic shock syndrome (STSS) and streptococcal meningitis syndrome (SMS). Three strains of streptococci were isolated respectively from the blood and cerebrospinal fluid of 6 cases. All these 6 strains were confirmed to be S. suis type 2 by culture characteristics, morphology, biochemical characteristics, serum antibody tests and fatty acid profile analysis. Animal model experiment showed that these strains were sensitive to rabbits and pigs, but not to rats. RAPD fingerprint test revealed an identity between human born and pig born strains. CONCLUSIONS: The aetiological agent of these human cases was S. suis type 2. Human cases were contracted by direct contact with the infected pigs or the corpse of infected pigs.

Adult↗
PubMed2000

[Analysis of the long-term results of late hand function reconstruction in patients with severe electrical injury of the wrists].

OBJECTIVE: To evaluate and analyze the long-term results of all the operation mordalities practised at present of late hand function reconstruction in patients with severe electrical injury of the wrists. METHODS: Forty-seven cases with late electrical injury of the wrists were followed up and comprehensively analyzed in terms of the long-term results of morphological reconstruction and functional restoration. RESULTS: In addition to cutaneous tissue repair and functional training of the joints of the wrists, the flexor digitorum reconstruction with auto free tendon grafting gave a poor result (only 33.4% of the cases with function above medium level). In one case, the wrist function was rebuilt by compound plantaris tendon free flap with leg deep facia and posterior tibial artery, resulting in the restoration of thumb flexor function, with shorter treating time and less postoperative adhesion. Median and ulnar nerves were repaired with free auto nerve grafting with no obvious effects. Two cases were repaired by compound tissue grafting of sural nerve and deep facia carried by small saphenous veins with uncertain result. In another 3 cases, with the aid of retrograde evoked potential (REP), a proximal anastomosis of nerves was done with fairly good result. CONCLUSION: Insufficient blood supply and scar formation were the major causes of poor results of the tendon and nerve grafting. It was recommended that the graft should carry sufficient blood supply to improve the blood supply of the recipient bed in order to improve the therapeutic effects. The selection of proximal nerve segment should include the functional examination.

Adolescent↗
PubMed2000

[The significance of the adhesion of CD(34)(+) stem/progenitor cells to fibronectin in the pathogenesis of chronic myelogenous leukemia].

OBJECTIVE: To investigate the significance of the adhesion of CD(34)(+) stem/progenitor cells to fibronectin in the pathogenesis of chronic myelogenous leukemia (CML). METHODS: (1) Integrin beta(1) chain (CD(29)) and alpha(4) chain (CD(49d)) expressions on CD(34)(+) cells were measured by flow cytometry in 30 untreated CML patients in chronic phase (CML-CP) and 10 healthy donors. (2) The adhesion function of immunomagnetic beads selected CD(34)(+) cells to fibronectin was detected by crystal violet staining in 5 untreated CML-CP patients and 5 healthy donors. (3) The effect of fibronectin on CFU-GM colony formation of bone marrow cells in 3 CML patients and 3 healthy donors was observed by limited dilution liquid microculture. RESULTS: (1) There was no significant difference in CD(29) and CD(49d) expressions on CD(34)(+) bone marrow cells between CML patients and healthy donors. (2) The adhesion of CD(34)(+) bone marrow cells to fibronectin decreased significantly in CML patients as compared with that in healthy donors (P < 0.01). (3) The CFU-GM colony formation was significantly inhibited by fibronectin in healthy donors (P < 0.01), but not in CML patients. CONCLUSION: The adhesion function abnormality of CML CD(34)(+) bone marrow cells to fibronectin may underlie the abnormal proliferation of CML progenitors.

Antigens, CD34↗
PubMed2000

Effects of microinjection of adenosine into area postrema on heart rate, blood pressure and renal sympathetic nerve activity in rats.

The effects of microinjection of adenosine (Ado) into area postrema (AP) on mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were examined in 53 anesthetized Sprague Dawley rats. The results obtained are as follows. (1) Following microinjection of Ado (1 ng/60 nl) into AP, MAP, HR and RSNA were decreased from 13.76+/-0.46 kPa, 356.28+/-4.25 bpm and 100+/-0% to 11.23+/-0.49 kPa (P<0.001), 336.91+/-5.23 bpm (P<0.01) and 70.95+/-5.19% (P<0.001), respectively; (2) 8-phenyltheophylline (150 microgram/kg, 0.2 ml,iv), a nonselective adenosine receptor antagonist, and 8-cyclopentyl-1,3-dipropylxanthine (500 microgram/kg, 0.2 ml, iv), a selective A(1) adenosine receptor antagonist, blocked the inhibitory effect of Ado completely; and (3) glibenclamide (5 mg/kg, 0.2 ml, iv), a blocker of ATP-sensitive potassium channel, also abolished the effect of Ado. The above results indicate that microinjection of Ado into AP induces inhibitory effects on MAP, HR and RSNA, which may be related to activation of ATP-sensitive potassium channels mediated by A(1) receptors.

Adenosine↗
PubMed2000

[Streptomycin inhibits carotid sinus baroreflex in anesthetized rats].

The effect of streptomycin on the carotid baroreflex was examined in 23 anesthetized rats with isolated carotid sinus perfusion. The results obtained are as follows. (1) By perfusing the isolated carotid sinus with streptomycin (100 micromol/L) the functional curve of baroreflex was shifted to the right and upward with its peak slope (PS) decreasing from 0.40+/-0.01 to 0.33+/-0.01 kPa (P<0.001), and the reflex decrease in the mean arterial pressure (RD) was lowered from 6.22+/-0.13 to 5.02+/-0.11 kPa (P<0.001), while the threshold pressure (TP), equilibrium pressure (EP) and saturation pressure (SP) were significantly increased from 8.27+/-0.25 to 10.33+/-0.32 kPa (P<0.01), 12.71+/-0.21 to 13.33+/-0.30 kPa (P<0.01) and 24.41+/-0.14 to 26.11+/-0.28 kPa (P<0.01),respectively. Among the functional parameters of carotid baroreflex, the changes in RD, PS and TP induced by streptomycin were dose-dependent. (2) By perfusing the isolated carotid sinus with adenosine (125 micromol/L), carotid baroreflex was facilitated. Pretreatment with streptomycin (200 micromol/L) not only eliminated the facilitated effect of ado on carotid baroreflex but also caused a reflex decrease in MAP to a level lower than control. Taken together, it is suggested that streptomycin can markedly inhibit the carotid sinus baroreflex in anesthetized rats.

Animals↗
PubMed2000

[K(ATP) channel opener facilitates carotid sinus baroreflex in anesthetized rats].

The effects of cromakalim (Cro), a K(ATP) channel opener, on the carotid baroreflex were studied in 32 anesthetized rats with perfused isolated carotid sinus. The results obtained are as follows. (1) By perfusing the isolated carotid sinus with Cro (10 micromol/L), the functional curve of the baroreflex was shifted to the left and downward, with a peak slope (PS) increasing from 0.36+/-0.01 to 0.48+/-0.01 kPa/kPa (P<0.001), whereas the reflex decrease in mean arterial pressure (RD) was increased from 5.78+/-0.14 to 7.87+/-0.12 kPa (P<0.001). Meanwhile, the threshold pressure (TP), equilibrium pressure (EP) and saturation pressure (SP) were all significantly decreased from 8.34+/-0.35 to 6.41+/-0.09 kPa (P<0.01), 12.71+/-0.25 to 11.78+/-0.24 kPa (P<0.01) and 24.89+/-0.25 to 22.56+/-0.16 kPa (P<0.001), respectively. Among the functional parameters of carotid baroreflex, the changes in RD, PS and TP induced by Cro were dose-dependent. (2) By pretreatment with glibenclamide (10 micromol/L), a K(ATP) channel blocker, the above effects of Cro on the carotid baroreflex were abolished. (3) The Cro-induced change in the baroreflex was enhanced by preperfusing with adenosine (125 micromol/L). On the basis of the above results, it is concluded that Cro facilitates the carotid baroreflex, an effect attributable to the enhanced stretch of baroreceptors by dilation of sinus wall as a result of K(ATP) channel activation.

Animals↗
PubMed2000

[Three-dimensional surface reconstruction of spiral CT for teeth and clinical use in examining impacted teeth of jaws].

OBJECTIVE: To establish a new technique for three-dimensional surface reconstruction of teeth (dental surface reconstruction), and apply it to investigate impacted teeth in bone before operation. METHODS: On the basis of three-dimensional surface reconstruction of teeth and jaws, the dental surface reconstruction is obtained with the technique of shaded surface display (SSD), making transparent bone around. This technique is applied to investigate 9 cases of supernumerary and impacted teeth. RESULTS: Dental surface reconstruction image can present the dental surface image including crown, root, neck and root bifurcation in three-dimensional way, without presenting the image of other tissue around. In 4 cases, the abnormal configuration, labial or palatal location, and relation with dentition in anterior maxilla of 5 supernumerary were shown. In 1 case, the shape, location, eruption orientation and the angle of orthodontic distraction of 1 impacted permanent canine were displayed. In 3 cases, the shape, location, and extraction resistance of 6 impacted wisdom teeth were revealed. In 1 case, the configuration, distance to adjacent molar of 1 impacted wisdom tooth, which is a transposition tooth in maxillary sinus, were also demonstrated. CONCLUSION: The dental surface reconstruction is a new technique to display three-dimensional surface configuration of teeth. This technique can be applied to examine impacted and supernumerary teeth before surgical and orthodontic treatment.

Adult↗
PubMed2000

[Alteration of free radical generation in pulmonary tissue after quick decompression].

The purpose of this experiment was to evaluate decompression-induced pulmonary injury by means of measurement of ascorbate free radical (Vc-.) alteration in pulmonary tissue of the rats which experienced rapid decompression. 29 male S-D rats were divided into 4 groups: A was executed at 45 min post-decompression; B was control for A; C was executed at 90 min; D was ontrol for C. Group A and group C were to compress up to 0.5 MPa(air) and stay for 60 min, then were decompressed smoothly to normbaric in 1 min. The 0.05 M N-tert-butyl-alpha-phenylnitrone (PBN) was given at 20 min after completion of decompression (groups A and B) or at 65 min (groups C and D). At 25 min after PBN injection the animals were killed by cutting arteria coeliaca, and 0.75 g pulmonary tissues were taken. These tissues were homogenized for electron paramagnetic resonance (EPR) assay. The results demonstrated that the ascorbate free radical (Vc-.) signals were obtained at all samples. The intensity of signals measured in group C rose markedly (P < 0.05) and that in group A was close to control's. So it can be concluded that rapid decompression would increase the generation of free radical in lung.

Animals↗
PubMed2000

[Resources and distribution of Cordyceps sinensis in Naqu Tibet].

This paper reported the resources and distribution of Cordyceps sinensis in Naqu district, the principally grown zone in Tibet. The investigation showed that the yearly yield of Cordyceps sinensis are 7000 kg, the distribution areas are Baqin, Suoxian, Biru, Jiali, Naqu and Nierong county at 30 degrees 20'-32 degrees 48' N, 92 degrees 0'-94 degrees 50' E. The rangs of vertical distribution from the elevation 5000 m to 4100 m; the ecological geographical distribution is affected mainly by vegetation, soil, temperature and humidity.

Animals↗
PubMed2000

[The ejection of ascoporae of Cordyceps sinensis].

This paper has reported the effect of sunshine to stromata of Cordyceps senensis grown in Kanding, Sichuan and Naqu, Tibet. The ejective time, quantity and germination rate of ascoporaes between the two habitats are different with sunshine. To satisfy the needs of sunshine, moisure and temperature can be raised the ejection and germination of ascorporae.

Animals↗
PubMed2000

[Effect of low dose gossypol treatment on male sperm nuclear basic protein].

OBJECTIVE: Study on human sperm nuclear basic proteins after low dose of gossypol treatment. METHODS: Twenty-three men with normal fertility were divided into two groups. The experimental group included 15 men which were treated daily with gossypol (15 mg/d for 12 weeks and treated with 10 mg/d for 32 weeks continuously), 8 men were used in the control group. Semen was collected at 1, 4, 8, 12, 16, 24, 36 and 44 weeks after gossypol treatment and 10 weeks after stopping treatment. Total nuclear basic protein (TNBP) was extracted and TH/TP, HP1/(HP2+HP3) ratios were determined by scanning microdensitometry following electrophoresis of TNBP in polyacrylamide gels. RESULTS: The TH/TP ratio of control and the gossypol treated group were 0.17 +/- 0.07 and 0.63 +/- 0.79(P < 0.05); The HP1/(HP2+HP3) ratio of control and gossypol treated group were 1.05 +/- 0.21 and 1.47 +/- 0.18 (P < 0.01). These two parameters were returned to normal after 10 weeks of stopping gossypol treatment. CONCLUSIONS: The interruption of histone-to-protamine replacement reaction (HPRR) and alteration of nuclear basic proteins induced by low dose gossypol treatment might lead to infertility. Changes of HPRR and nuclear basic protein were reversible after stopping gossypol treatment.

Adult↗
PubMed2000

[Ganciclovir induces apoptosis of rat C6 glioma cell transduced with HSV-tk gene].

OBJECTIVE: To observe whether apoptosis could be induced by ganciclovir (GCV) in the herpes simplex virus-thymidine kinase gene-ganciclovir system (HSV-tk-GCV system) gene therapy for glioma. METHODS: Transduced C6/tk glioma cell as treated group, wild C6 cell as control group, were studied with morphology, gel-electrophoresis of DNA fragment analysis, fluoroscopy, and flow cytometric study before or after exposed to GCV, and apoptosis of transduced C6/tk glioma cell was ascertained. RESULTS: When C6/tk cell was treated with GCV at 5 micrograms/ml for 72 hours, cell apoptosis occurred. Typical apoptotic morphological features included cell shrinkage, condensation, and margination of nuclear chromatin were showed by light and electron microscopy, condensed nuclear chromatin and the fragment of nuclei were demonstrated by fluoroscopy, DNA ladder was showed by DNA fragment analysis, apoptotic peak was identified by flow cytometric study. The apoptotic cells accounted for 23% of the cell population. Apoptosis was not observed in control group treated by GCV. CONCLUSIONS: The apoptosis of transduced C6/tk glioma was induced by GCV, which fit in with the basis of HSV-tk-GCV gene therapy for glioma.

Animals↗
PubMed2000

[Abnormal infrared effects (AIREs) of nm-Ru/GC electrode towards CO adsorption in alkaline solutions].

The adsorption of CO on electrode of nanometer thin film of Ru in 0.1 mol.L-1 NaOH solution was studied by using in-situ FTIR spectroscopy. The results revealed that the adsorbed CO in alkaline solutions is mainly in linear bonded from that yields IR absorption at around 1,960 cm-1, and a small portion of bridge bonded CO was also determined near 1,780 cm-1. The band centers of COL and COB have been red-shifted respectively about 50 and 60 cm-1 in comparison with the values measured in acid medium. The enhancement factor of IR absorption of CO on nm-Ru/GC electrode has been measured at 33 in 0.1 mol.L-1 NaOH solution, which is more than 2 times larger than the value determined in a 0.1 MH2SO4 solution.

English Abstract↗
PubMed2000

[In situ time-resolved FTIR studies of HCOOH oxidation on Pt(100)/Sb electrodes].

The electrocatalytic oxidation of formic acid on Pt(100)/Sb electrodes of different coverage of Sb was investigated by using electrochemical techniques and in situ time-resolve FTIRS. The results demonstrated that the dissociative adsorption of formic acid was inhibited by the presence of Sbad on Pt(100) surface, as a consequence HCOOH can be oxidized directly into CO2 via reactive intermediates. The rate of oxidation of formic acid varied with the coverage of Sbad. It was revealed that at a Sbad coverage of 0.24 the Pt(100)/Sb electrode exhibited the highest electrocatalytic activity for HCOOH oxidation.

English Abstract↗
PubMed2000

[In-situ FTIR spectroscopic studies of electro oxidation of ethanol in alkaline media at a nm-Pt/GC electrode].

The electro-oxidation of ethanol on a nm-Pt/GC electrode in alkaline solutions was investigated by using cyclic Voltammetry and in-situ FTIR spectroscopy. The results demonstrated that the main product of ethanol oxidation was CH3COO-, only small quantity of CH3CHO was determined simultaneously. In contrast with the dual path reaction mechanism for the oxidation of ethanol in acid media, the oxidation of ethanol in alkaline media was revealed via the intermediate process of dissociative adsorption.

English Abstract↗
PubMed2000

[A rapid graphite furnace atomic absorption spectrometric method for the determination of trace copper and lead in surface water].

A rapid graphite furnace atomic absorption spectrometric method for the determination of trace copper and lead in surface water is investigated in this paper. The influences of the program for graphite furnace and matrix modifier are systematically researched. A rapid method without ashing step and chemical matrix modifier is established. The determination limits of copper and lead are 0.9 microgram.L and 1.2 micrograms.L, respectively. The relatively standard deviations (RSD) (n = 1) are 2.5% and 4.1%, respectively. The recoveries are 96.0%-97.2% and 90.0%-92.0%, respectively.

Copper↗