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Biomedical subjects

X Chen

Publications and source records attributed to X Chen.

At least 559 records · Page 31Linked to original sources
PubMed2000

[Determination of scalp ER and AR of patients with male pattern baldness and the effects of hair transplantation on them].

OBJECTIVE: To study the role of sex hormone receptor capacity of the scalp in male pattern baldness(MPB). METHODS: Estrogen receptor(ER) and androgen receptor(AR) assays were performed using fluorescent steroid hormone conjugate technique (FSHCT) in hairness and bald scalp in 8 patients with MPB. Changes of ER and AR capacity in recipient and donor sites of hair transplantation in MPB scalps were examined. RESULTS: The percentage of AR staining cells in the outer root sheath, sebaceous gland and bulb papilla of the lesional scalps was significantly higher than that of hairness scalps (P < 0.01). The percentage of ER positive cells in the outer root sheath of lesional scalps increased significantly (P < 0.01). CONCLUSION: Changes of contents of sex hormone receptors(SHR) in some sensitive area of the scalp induce MPB.

Adult↗
PubMed2000

[Application of polyester fiber heart patches to secondary intraorbital implantation of hydroxyapatite spheres].

OBJECTIVE: To observe the effect of intraorbital implantation of hydroxyapatite spheres wrapped with polyester fiber heart patches. METHOD: According to the rectus contraction points four rectus were found and the rectus valves were created in anophthalmos. Then the hydroxyapatite sphere wrapped by the polyester fiber heart patch was inserted in the orbit. RESULT: There were 13 cases in this group. Of them 11 patients showed very good operative results, Local poor healing of bulbar conjunctiva and fascia occurred in 2 patients. The wound in one patient healed very well after a simple repairing operation and in the other the wound healed spontaneously without any special treatments. CONCLUSION: The effect of secondary intraorbital implantation of hydroxyapatite spheres wrapped by polyester fiber heart patches is positive. The polyester fiber heart patch is safe, reliable, cheap, very convenient in use and easy to obtain. It is a better substitute for sclera which is used to wrap the HA sphere.

Adult↗
PubMed2000

[Influence of genetic background of photoperiodic response on expression of short photoperiod sensitive male sterility in rice].

The photoperiodic response of F1 and its parents was analyzed, and the photoperiodic response and short photoperiod sensitive male sterility of F2 progenies were studied in this paper. The results showed that the strong response was dominant over the weak response to photoperiod. The photoperiodic response of plants with short photoperiod sensitive male sterility in F2 was above medial degree(the rate of heading acceleration > 15%). Photoperiodic response showed a positive correlation with short photoperiod sensitive male sterility. The main sterility genes of Yid1s and Yid2s were allelism. It can be inferred that the short photoperiod sensitive male sterile gene might be expressed upon the presence of the photoperiodic response genes, and that the short photoperiod sensitive male sterility of plants with the same genes could differ in their reproductive expressions, not because of the changes of the genes, but the difference in genetic backgrounds of photoperiodic response.

Fertility↗
PubMed2000

[Response of wheat seedlings with different drought resistance to water deficiency and NaCl stresses].

The growth, photosynthesis, transpiration and antioxidative defence system of the seedlings of drought-tolerant wheat strain 8139 and drought-sensitive strain Ganmai No. 8 at 20% PEG 6000 and 1.2% NaCl stresses were compared. The results showed that strain 8139 had a strong drought resistance, but a weak salt resistance. The root growth of both wheat strains was inhibited significantly under salt stress, but stimulated slightly under drought stress. The net photosynthetic rate and water use efficiency of strain 8139 were significantly different from those of Ganmai No. 8 at every stage under both drought and salt stresses, and its transpiration rate was significantly different from that of Ganmai No. 8 only at 7th and 14th day after being stressed. The MDA content in strain 8139 after being stressed for 7 days was much lower than that in Ganmai No. 8 under drought stress, but there was no significant difference between the two strains under NaCl stress. Correspondingly, there was no significant difference in the fructan content and SOD and APX activities between strain 8139 and Ganmai No. 8, but a significant difference in GSH content was found under salt stress. Under drought stress, the contents of fructan and GSH and the activities of SOD and APX in strain 8139 were much higher than those in Ganmai No. 8 at different stage, and strain 8139 exhibited a strong antioxidative defence ability.

Disasters↗
PubMed2000

[Occurrence and control of frost in Tilia amurensis and Fraxinus mandshurica young plantations].

The changes of minimum temperature periodical biological phenomena and frost in yound Tilia amurensis and Fraxinus mandshurica plantation stands were systematically analyzed based on the vertical gradient observation and plot investigation. Meanwhile, the resistance of Tilia amurensis to late frost was also studied. The results showed that the phenophase of T. amurensis was later than that of F. mandshurica. Influenced by significant temperature inversions in this area, the phenophase of T. amurensis and F. mandshurica changed regularly in different aspects and slope positions. The sprouts on west slope started earlier than that on east slope. The higher they grew on the slope, the earlier they sprouted, with the earliest sprout at the top of slope. Late frost in this area only took place when the trees were sprouting, but air temperature decreased significantly at the same time. The degree of injury from the late frost could be controlled effectively by selecting suitable site. Sites down the slope, especially the east slope, were not suitable for T. amurensis and F. mandshurica plantation in this research area. Chemical treatment and biological shading could prevent late frost injury through putting off sprout. Mixed plantations could prevent F. mandshurica and T. anurensis from late frost injury significantly, and the frost injury index and the proportion of the tree number of different injury grades were lower than those in pure stands.

Climate↗
PubMed2000

[Effect of elevated CO2 concentration on photosynthesis and antioxidative enzyme activities of wheat plant grown under drought condition].

The photosynthesis and antioxidative enzyme activities of wheat plants grown in two open-top chambers with CO2 concentrations of 350 mumol.mol-1 and 700 mumol.mol-1 were examined under drought stress. The result showed that elevated CO2 concentration obviously enhanced the photosynthesis, stomatal resistance and water use efficiency, but decreased the transpiration of wheat. Doubled CO2 concentration significantly increased the activities of CAT, POD and SOD, which enhanced the abilities of antioxidative defence and drought tolerance.

Carbon Dioxide↗
PubMed2000

[Factors affecting colonization of introduced microorganisms on plant roots].

Microorganisms such as biological control agents (BCA), plant growth-promoting rhizobacteria (PGPR) and yield increasing bacteria (YIB) were introduced along growing roots. The colonization process of introduced bacteria was proved that they attached root tipfirst, then distributed along roots, multiplicated there, and survived as certain population size. The colonization location was closely related with root exudates, which was usually at the junction between cortex cells or at the base of lateral roots or root hairs. The variation of colonization by introduced microorganisms in the rhizosphere was caused by biotic and abiotic factors. Biotic factors included the physiological characters of introduced microorganisms and interactions between introduced microorganisms and native microbes. The more important factors were plant genotypes which associated with introduced beneficial microbes and regulated the population and community of those microbes affecting the colonization of introduced microorganisms. Abiotic factors here referred to soil environmental conditions, e.g., soil texture, water content, soil temperature and pH value.

Ecosystem↗
PubMed2000

[Simulation of potential responses of clear-cut of mixed coniferous and broadleaved Korean pine forest in Yichun to climate change by BKPF model].

The potential responses of forest succession in the clear-cut site of mixed coniferous and broad-leaved Korean pine forest (MCBLKPF) in Yichun, Heilongjiang Province to global climate change and elevated CO2 after 50 years by BKPF model were simulated. The results indicated that the densities of Pinus koraiensis and hardwood species(Fraxinus mandshurica, Tilia amurensis, Juglans mandshurica and Phellodendron amurense) would increase, while the densities of Larix olgensis, Betula platyphylla and Populus davidiana would decrease after 50 years. The stand densities would be slightly lower than those at the same age under the current climate condition. The stand productivity, total aboveground biomass and leaf area index will increase by 7-28%, 15-24% and 5-8%, respectively. Climate change would be beneficial to the forest succession from the clear-cut site to MCBLKPF.

Climate↗
PubMed2000

Noninvasive three-dimensional computed tomographic angiography in preoperative detection of intracranial arteriovenous malformations.

OBJECTIVE: To assess the value of noninvasive three-dimensional computed tomographic angiography (3D-CTA) in preoperative detection of intracranial arteriovenous malformations (AVMs). METHODS: A prospective evaluation at a single institute over a 2-year period included 23 patients suspected of intracranial AVMs. All patients underwent 3D-CTA and digital subtraction angiography (DSA). Results from both procedures were compared. RESULTS: 3D-CTA imaging provided excellent visualization of intracranial AVMs. The false positive error and false negative error were zero in our sample. The details of arterial supply (numerical measure, orientation, caliber and routing) and vascular nidus (size, morphosis and location) provided by 3D-CTA images were the same as DSA and the details of venous drainage were an approximate match. Additionally, 3D-CTA can depict tridimensional anatomical information for AVMs and their relationship to adjacent structures, a function not possible with DSA. This assisted the surgeons in making better surgical planning and reduced trauma. As a noninvasive course, there were no related-complications in the course of 3D-CTA processing. CONCLUSIONS: DSA is still regarded as the gold standard for intracranial AVMs detection. The modality of 3D-CTA is accurate, noninvasive, nearly risk free and low-price; we could routinely use it instead of or as a supplement to DSA, in the preoperative detection of suspected intracranial AVMs and postoperative radiological follow-up. 3D-CTA adds tridimensional aspect and assists the surgeon in a the more accurate therapeutic scheme. Preliminary data suggest that 3D-CTA is playing a favorable role in the assessment of patients with intracranial AVMs.

Adolescent↗
PubMed2000

[AP-1 mediated signal transduction in thrombin-induced regulation of PAL-1 expression in human mesangial cells].

OBJECTIVE: To evaluate activator protein-1 (AP-1) mediated mechanisms in thrombin-induced qlasminogen activator inhibitor-1 (PAI-1) expression in cultured human glomerular mesangial cells (MCs). METHODS: Electrophoretic mobility shift assay (EMSA) was employed to assess AP-1 DNA-binding activity, and Western blot hybridization was used for quantification of c-fos and c-jun, two subunits of AP-1 dimers. PAI-1 activity and mRNA expression were analysed by the fibrin plate assay and Northern hybridization, respectively. RESULTS: Thrombin concentration enhanced PAI-1 activity in the supernatant and stimulated PAI-1 mRNA expression in cultured MCs. PAI-1 activity was blocked by hirudin, a specific inhibitor of thrombin. Further study demonstrated that thrombin promoted AP-1 DNA-binding activity but exerted little effect on c-fos or c-jun. Curcumin (AP-1 inhibitor), staurosporine (PKC inhibitor), and genistein (PTK inhibitor) all reduced AP-1-mediated PAI-1 mRNA expression induced by thrombin in cultured MCs. CONCLUSION: The present study indicates that in cultured human MCs, thrombin stimulates PAI-1 expression through an AP-1 signal pathway, which may be mediated by PKC and PTK.

Cells, Cultured↗
PubMed2000

[A study on the relationship between serum free alpha-subunit of human chorionic gonadotropin and pregnancy induced hypertension].

OBJECTIVE: To determine the correlation of free alpha subunit of human chorionic gonadotropin (F alpha-hCG) with pregnancy induced hypertension(PIH), and to observe the immunohistochemical expression of alpha-hCG in placentae from PIH. METHODS: Serum was obtained from 66 successive pregnant women diagnosed with PIH (5 mild, 8 middle and 53 severe) at 21-43 weeks' gestation. A group of 30 non PIH gravid women were used as controls. The serum was assayed for F alpha-hCG by monoclonal technology and human prolactin was assayed for correcting the blood contraction. Immunolocalization and the intensity of the immunohistochemical stained in the placentae from 13 PIH and 13 normal pregnancies. RESULTS: Significant difference was noted between the two groups mean of F alpha-hCG (the control group VS PIH group was 528 +/- 421 IU/L VS 222 +/- 129 IU/L, P < 0.001); no significant between two groups of hPL. The mean value of F alpha-hCG of severe PIH revealed significantly higher than the mild and moderate (569 +/- 455 IU/L VS 363 +/- 159 IU/L, P < 0.01); The leve of F alpha-hCG in group of proteinuria > or = +++ was higher than that of proteinuria < +++ (598 +/- 474 IU/L VS 425 +/- 291 IU/L, P > 0.05). The intensity of alpha-hCG immunostaining in syncytiotrophoblast was significantly increased in 13 PIH compared with the control group (the strong positive rate 10/13 VS 3/13 P < 0.025). CONCLUSIONS: The level of F alpha-hCG are significantly higher in PIH compared with controls. The more severe the higher level of F alpha-hCG is in PIH. The higher level of alpha-hCG has the basement of placentae pathology.

Female↗
PubMed2000

Molecular epidemiologic study of Mycoplasma genitalium infection in high risk populations of sexually transmitted diseases in China.

OBJECTIVE: To detect Mycoplasma genitalium (Mg) infection in high risk populations of sexually transmitted diseases (STDs) from several cities in China and to clarify the possible role of Mg in the pathogenesis of non-gonococcal urethritis. METHODS: Polymerase chain reaction (PCR) based on 2 pairs of primers, one for Mg-Pa (adhesion protein) and the other for 16S-rRNA (Mycoplasma genera) was used to detect Mg infection. Urogenital specimens of different high risk populations and urethritis patients, were collected from the Guangdong, Kunming, Shanghai, Nanjing, and Changzhou areas. RESULTS: The positive detection rate of Mg-DNA in high risk populations of STDs was significantly higher than that of the control group (chi 2 = 7.82, P < 0.01). The positive detection rates in Guangdong STD clinics and promiscuous persons from Kunming were higher than those from the Shanghai, Nanjing, and Changzhou areas (chi 2 = 8.54, P < 0.01 and chi 2 = 5.89, P < 0.05). Mg DNA could be detected in those patients without other relevant pathogens. Some patients were simultaneously infected with Mg and other microbes, such as Chlamydia trachomatis and/or Ureaplasma urelyticum. The positive Mg-DNA detection rate in patients with urethritis symptoms was higher than in patients without the symptoms (chi 2 = 11.68, P < 0.01). CONCLUSION: Mg infection exists in high risk populations of STDs in China, and the Mg infection rate is different among different high risk groups.

Adolescent↗
PubMed2000

Relationship between the burden of Pneumocystis carinii, the inflammatory reaction and lung injury in Pneumocystis carinii pneumonia.

OBJECTIVE: To study the relationship between the burden of Pneumocystis carinii (P. carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF) in a rat model of P. carinii pneumonia (PCP). METHODS: Clean grade 50 male Sprague-Dawley rats were immunosuppressed by a subcutaneous injection of 25 mg cortisone acetate twice a week for 8-12 weeks; the PCP model was successfully induced in 14 rats. The inflammatory reaction and biochemical markers of the activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and type IV collagenase (matrix metalloproteinases, MMP-2, MMP-9) as well as the values of total protein (TP) and albumin (ALB) in BALF between the mild burden group of P. carinii (involved alveoli < 25% per 100 alveoli, Group A) and the moderate to severe burden group (involved alveoli > or = 25% per 100 alveoli, Group B) were measured. The other six clean grade SD rats served as normal control group (Group C). RESULTS: The total white cell count in BALF was higher in Group B [(6.8 +/- 1.7) x 10(6)/L] than in Group A [(3.8 +/- 1.2) x 10(6)/L] (P < 0.01); however, there were no differences in white cell differentiation. Assays of biochemical markers showed that ALB in BALF in Group B (0.893 +/- 0.469 g/L) was increased in comparison with Group A (0.262 +/- 0.169 g/L); it was only 0.026 +/- 0.021 g/L in Group C. The contents of TP and activities of LDH were higher in Group B (TP 1.756 +/- 0.706 g/L, LDH 2580 +/- 550 U/L) than in Group A (TP 0.784 +/- 0.553 g/L, LDH 1410 +/- 620 U/L); the values of TP and LDH were 0.063 +/- 0.020 g/L and 370 +/- 250 U/L respectively in Group C. The activity of Type IV collagenase, including MMP-2 and MMP-9, was higher in Group B than in Group A (P < 0.01) (MMP-2: 1102 +/- 169 grey value vs 459 +/- 274 grey value; MMP-9: 1218 +/- 257 grey value vs 449 +/- 225 grey value). There was no activity of Type IV collagenase in BALF of Group C. No statistically significant difference was observed in ALP between the groups B and A. CONCLUSIONS: These results indicate that there is a significant correlation between the burden of P. carinii in lung tissues and the inflammatory reaction as well as biochemical markers of the resultant activity of lung injury.

Albumins↗
PubMed2000

[Prenatal diagnosis of fetal congestive heart failure by color flow imaging and pulse Doppler ultrasound].

OBJECTIVE: To investigate prenatal diagnosis of fetal congestive heart failure (CHF) by Color Doppler Flow Imaging (CDFI) and pulse Doppler Ultrasound (PU). METHODS: 3,841 pregnant women were detected by ultrasound. Maternal-placental-fetal circulation surveillance by high resolution Doppler ultrasound was performed in 302 high-risk pregnancies. The diagnosis of CHF is dependent upon (1) The cardiac area/chest area ratio > 0.33; (2) An abnormal umbilical vein pulsation; and (3) Tricuspid regurgitation. RESULTS: There were six deaths that all had abnormal umbilical vein pulsation and five cases who had C/T area ratio > 0.33. CHF accounted 0.17% in all the pregnancies and 2% in high-risk pregnancies. CONCLUSIONS: The results suggest that blood velocity recording abnormal pulsed sign in the umbilical veins and C/T area ratio of the fetus can give valuable clinical information with regard to the presence of fetal CHF. Fetus with CHF almost always had poor outcome. CDFI and PU may have implications for fetal diagnostic work-up and prognosis.

Adult↗
PubMed2000

[Detection of DNA extracted from Mycobacterium tuberculosis by TaqMan-PCR technique and its clinical application].

OBJECTIVE: To evaluate the clinical diagnostic value of TaqMan-PCR technique in the diagnosis of active pulmonary tuberculosis. METHODS: The specimens of sputum and peripheral blood from 168 patients with active pulmonary tuberculosis, 57 patients with lung cancer and the specimens of peripheral blood from 34 healthy individuals were detected by TaqMan-PCR, PCR. The specimens of sputum were also detected by smear, culture with BACTEC and Lowenstein-Jensen for comparison. RESULTS: The positive rates of sputum and peripheral blood detected by TaqMan-PCR were 53.0% and 61.3%, respectively, significantly higher than those of PCR, smear, culture with BACTEC and Lowenstein-Jensen (P < 0.05). There was no significant difference between TaqMan-PCR and PCR for specificity (P > 0.05). Of 105 specimens of peripheral blood from patients with smear-negative and culture-negative pulmonary tuberculosis, 48 specimens of peripheral blood detected by TaqMan-PCR were positive. The positive rate was 45.7%. CONCLUSIONS: TaqMan-PCR method showed higher sensitivity and specificity. It is an useful tool for diagnosis of pulmonary tuberculosis, particularly smear-negative and culture-negative pulmonary tuberculosis.

DNA, Bacterial↗
PubMed2000

[Clinical observation of elderly idiopathic nephrotic syndrome treated with integrated traditional Chinese and Western medicine].

OBJECTIVE: To observe the clinical effect of integrated traditional Chinese and western medicine (TCM-WM) in treating the elderly idiopathic nephrotic syndrome (INS). METHODS: Eighty-two patients of the elderly INS were randomly divided into the TCM-WM group and the control group. Forty-one patients of the TCM-WM group were treated with prednisone, Cytoxan (CTX) and Chinese medicinal herbs according to Syndrome-type, the other 41 patients of the control group were treated with WM alone. Clinical remission rate, adverse reaction, recurrence rate and remission period were observed. RESULTS: The complete remission rate and total remission rate of the TCM-WM group were 58.5% and 85.4%, significantly higher than those of the control group (39.0%, 63.4%, P < 0.01). The adverse reaction rate of the TCM-WM group (36.6%) was significantly lower than that of the control group (80.5%, P < 0.01). A follow-up of 35.1 +/- 9.7 months showed that there was no significant difference in the recurrence rate between two groups (P > 0.05), but the average remission period (30.6 +/- 3.8 months) of the TCM-WM group was significantly longer than that of the control group (12.7 +/- 3.7 months, P < 0.01). CONCLUSION: TCM-WM treatment is obviously superior to treatment with WM alone in increasing clinical remission rate, relieving adverse reaction rate and extending remission period.

Aged↗
PubMed2000

[Clinical study on zhenjian granule in improving essential hypertension and insulin resistance].

OBJECTIVE: To observe the effect of Zhenjian granule (ZJG) on lowering the blood pressure and improving the essential hypertension (EH) and insulin resistance (IR). METHODS: Fifty-two hypertensive patients were randomly divided into the treated group (30 patients) with ZJG and the control group (22 patients) with captopril for 4 weeks, then the variation of levels of blood pressure, blood glucose, blood insulin (radioimmunoassay), insulin sensitivity index (ISI) and blood lipid before and after treatment were determined, and compared with the normal group (17 healthy subjects). RESULTS: Fasting insulin, blood glucose and insulin 2 hours after meal were significantly higher than those of the normal control, but the ISI was significantly lower than that of the normal control (P < 0.01), the insulin resistance existed; after treatment, not only the blood pressure obviously lowered (P < 0.05, P < 0.01), and the fasting insulin, blood glucose and insulin 2 hours after meal obviously lowered (P < 0.05, P < 0.01), ISI markedly raised (P < 0.05, P < 0.01). The IR of both groups was improved, the blood lipid of the treated group was also improved. CONCLUSION: ZJG was effective in reducing blood pressure, it also had significant effect on improving metabolic disorder, particularly on IR in EH patients.

Adult↗