Biomedical subjects

Y Lu

Publications and source records attributed to Y Lu.

At least 361 records · Page 20Linked to original sources

PubMed2000

[Selective isolation of isopsoralen from crude extract of Psoralea corylifolia. L by using inclusion method of host-guest molecules].

AIM: To isolate the chemical components from extracted crude of Psoralea corylifolia L. METHODS: Applicate the function of molecular recognition in supramolecular chemistry, use 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol as the host molecule and chemical components in extracted crude of Psoralea corylifolia L. as guest molecules, which represent different from either in sort, quantity and sites of function groups or in structural topological character, 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol could selectively form inclusion compound with component endowed with interactional complementarity and isolate as crystalline from the extracted crude of Psoralea corylifolia L. RESULTS: The isopsoralen as guest molecule is selectively included by 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol in inclusion crystal and removed by acetone from the inclusion compound and total yield is 0.18%. Isopsoralen is determined by UV, IR, 1HNMR and MS and its inclusion compound is determined by means of IR, powder XRD and single crystal XRD. The isolation effect is analyzed by GC/MS. CONCLUSION: The method is simple and selective for isolation isopsoralen from extracted crude of Psoralea corylifolia L.

Furocoumarins↗

PubMed2000

[Detection of Mycoplasma genitalium in throat by nested polymerase chain reaction and analysis of DNA sequencing in pediatric patients with acute upper respiratory tract infections].

OBJECTIVE: To explore the relation between Mycoplasma genitalium (Mg) and acute upper respiratory tract infection in pediatric patients by using nested polymerase chain reaction(nPCR) and analysis of DNA sequencing techniques. METHODS: The specimens of throat swab were obtained in 62 acute upper respiratory tract infections children and 80 health children. The two kinds of Mg species-specific, in which the sequences of I-III and V-VII variable regions of Mg 16Sr RNA gene were detected by using nPCR technique. DNA sequences of positive product were detected and analysed. RESULTS: The Positive rate of health children is 5% (4/80), while the acute upper respiratory tract infection children is 21% (13/62). The difference is significant (P < 0.001). The DNA sequences of positive product shows that: there are two point mutation(T-->C) in the sequences of V-VII variable regions of throat swab of one pediatric patient, other sequences are same as those Mg type strain(G-37T). CONCLUSIONS: Acute upper respiratory tract infection of pediatric patients have relation with Mg. There are Mg mutant strain in China.

Adhesins, Bacterial↗

PubMed2000

[Plasma total homocysteine and pulmonary thromboembolism].

OBJECTIVE: To investigate whether the elevated plasma homocysteine increases the risk of pulmonary thromboembolism in the Chinese population. METHODS: Sixty-nine patients with pulmonary thromboembolism and 90 sex- and age-matched healthy controls were recruited, and the patients were diagnosed using lung ventilation/perfusion scan and/or ultrafast CT as well as medical history. The concentration of plasma total homocysteine (tHcy) was measured with high performance liquid chromatography and environmental factors were collected. RESULTS: No significant difference was seen in family history of pulmonary thromboembolism and cardiovascular diseases, cigarette smoking, alcoholic drinking, oral contraceptive and body mass index between cases and healthy controls. The concentration of plasma tHcy in cases was significantly higher than that in healthy controls (16.60 mumol/L +/- 1.75 mumol/L vs 12.48 mumol/L +/- 1.47 mumol/L; t = 3.821, P < 0.05), and adjusting for environmental factors did not change the significance. The plasma tHcy in the isolated pulmonary thromboembolism patients was lower than that in the patients who had lower limb deep venous thrombosis, but no significant difference was found. Compared with normal plasma tHcy, hyperhomocysteinemia was associated with a 4.99-fold risk of pulmonary thromboembolism. CONCLUSION: Our results show that the elevated plasma tHcy increases the risk of pulmonary thromboembolism, and hyperhomocysteinemia is an independent risk factor of pulmonary thromboembolism in the Chinese population.

Adult↗

PubMed2000

A method for removal of CO from exhaust gas using pulsed corona discharge.

An experimental study of the oxidation of CO in exhaust gas from a motorcycle has been carried out using plasma chemical reactions in a pulsed corona discharge. In the process, some main parameters, such as the initial CO concentration, amplitude and frequency of pulses, residence time, reactor volume, and relative humidity (RH), as well as their effects on CO removal characteristics, were investigated. O3, which is beneficial to reducing CO, was produced during CO removal. When the exhaust gas was at ambient temperature, more than 80% CO removal efficiency was realized at an initial concentration of 288 ppm in a suitable range of the parameters.

Air Pollution↗

PubMed2000

[Study on the relationships between leptin levels and weights of mothers and infants and the relationships of cord serum leptin to C-peptide, insulin and insulin like growth factor-II].

OBJECTIVE: To determine the relationships between serum leptin levels and maternal weights in late pregnancy and cord blood leptin levels to birth-weights, C-peptide, insulin and insulin like growth factor (IGF-II). METHODS: Fifty normal pregnant women at 37-38 weeks and their newborns were studied, and 29 non-pregnant women were set as control. Venous blood was taken from women and from the cord at delivery. Blood leptin and cord blood C-peptide, insulin, and IGF-II were measured by radio-immunoassay. RESULTS: The average leptin level in maternal sera was (13.62 +/- 3.68) micrograms/L, significantly higher than that in the control (6.60 +/- 3.04) micrograms/L and that in cord blood (8.05 +/- 4.61) micrograms/L. Maternal leptin levels were significantly correlated with maternal weights and body mass index (BMI. r = 0.33, 0.35, P < 0.05), but not with infant birth-weights (r = 0.10, P > 0.05). Cord blood leptin levels were significantly correlated with birth-weights and BMI (r = 0.54, 0.49, P < 0.001) but have no correlation with maternal leptin levels (r = 0.19, P > 0.05). Significant difference of the cord leptin levels was not seen between the males and females. The cord blood C-peptide was (0.86 +/- 0.35) microgram/L, insulin (8.49 +/- 4.76) mU/L and IGF-II (0.218 +/- 0.076) microgram/T. Cord leptin levels were correlated with C-peptide levels (r = 0.37, P < 0.05), but not with insulin and IGF-II levels (r = 0.19, -0.14, P > 0.05). CONCLUSIONS: Maternal leptin levels in late pregnancy were significantly higher than those in normal non-pregnant women and positively correlated with maternal weights and BMI. Cord blood leptin levels were positively correlated with birth-weights and BMI of the newborns. The leptin levels of cord blood were correlated with those of C-peptide but not insulin and IGF-II.

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

The cellular and molecular mechanism of laminin-glycopeptides on anti-metastasis.

OBJECTIVE: To further study the anti-metastasis mechanism of laminin-glycopeptides on carcinoma cell proliferation, apoptosis and the secretion of matrix metalloproteinases. METHODS: Human hepatocellular carcinoma cells in serum free medium were incubated on laminin-coated substrate with or without laminin-glycopeptides at a final concentration of 50 micrograms/ml. The total number of surviving cells after incubating for the indicated time was assayed by MTT assay. DNA synthesis of the incubated cells was detected by 3H-TdR incorporation. Cell cycle was analysed by FACS. The mitotic index of Giemsa stained cells was assessed. Cell apoptosis was detected by both FACS and an acridine orange staining method. Matrix metalloproteinase secretion was analysed by gelatin zymography. RESULTS: The total number of surviving cells incubated on laminin in the absence of laminin-glycopeptides was significantly larger than that in the presence of laminin-glycopeptides. Laminin promoted 3H-TdR incorporation of carcinoma cells, decreased the percentage of cells in G1 phase and increased the percentage of cells in S phase. In contrast, laminin-glycopeptides could inhibit the effect of laminin as shown by 3H-TdR incorporation and cell cycle analysis. The percentage of cells in G2 + M phase and the mitotic index among various groups showed no significant difference. Matrix metalloproteinases secretion from cells treated by laminin-glycopeptides was much less compared to that without the treatment by laminin-glycopeptides. CONCLUSION: Laminin may stimulate cell proliferation, while laminin-glycopeptides could significantly inhibit the effect of laminin by inhibiting DNA synthesis and arresting the carcinoma cell cycle from G1 to S phase. These effects may inhibit not only tumor growth of the primary carcinoma, but also the establishment of metastases at ectopic tissues. Laminin-glycopeptides could also inhibit the secretion of matrix metalloproteinases from carcinoma cells and this may contribute to their decreased invasive and metastatic phenotype. This study further revealed the cellular and molecular mechanism of laminin-glycopeptides on anti-metastasis.

Apoptosis↗

PubMed2000

Relationship between gene expression of nitric oxide synthase and androgens in rat corpus cavernosum.

OBJECTIVE: To clarify the dependence of neural nitric oxide synthase mRNA (nNOSmRNA) and endothelial nitric oxide synthase mRNA (eNOSmRNA) on androgens (testosterone [T] and dihydrotestosterone [DHT]). METHODS: 160 male Sprague Dawley (SD) rats were divided into Groups A (56 rats, 5 weeks old), B (50 rats, 10 weeks old) and C (54 rats, 58 weeks old). Groups A, B and C were all subdivided respectively into five Subgroups. Subgroup 1: intact controls; Subgroup 2: castrated; Subgroup 3: castrated with testosterone undecanoate 25 mg/kg.mon-1, intramuscular injection, Subgroup 4: castrated with testosterone undecanoate 50 mg/kg.mon-1, intramuscular injection and Subgroup 5: treated with finasteride 4.5 mg/kg.day-1, orally. Four and ten weeks after treatments described above, one half of the rats were killed. Serum samples were taken for measurements of T, free testosterone (FT) and DHT by radioimmunoassay. Penile samples were treated with liquid nitrogen and then stored at -80 degrees C. nNOSmRNA and eNOSmRNA were detected by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) and Dot blot. RESULTS: There was no significant difference between Subgroup 1 and Subgroup 2 or Subgroup 5 in all Groups A, B and C. The expression of penile eNOSmRNA of Group A was significantly increased (4 weeks model) (P < 0.05) or increased (10 weeks model) (P > 0.05) in Subgroup 2 or 5 compared with those in Subgroup 1. There was no significant difference between Subgroup 1 and Subgroup 2 or Subgroup 5 of Group B in 4 weeks model (P > 0.05). There was an elevation when animals were castrated or treated with finasteride in the 10 weeks model. The expression of penile eNOSmRNA of Group C was significantly increased (10 weeks model) (P < 0.05) or increased (4 weeks model) in Subgroup 2 compared with those in Subgroup 1. The production of eNOSmRNA in Subgroup 5 was also increased (including 4- and 10-week models). When T was supplied for castration, the penile eNOSmRNA was decreased to some extent; the greater the dose of T given, the lower penile eNOSmRNA was observed. CONCLUSIONS: The expression of eNOSmRNA in SD rat penile tissue increases while T or DHT diminishes. Sometimes androgens modulate penile eNOSmRNA in opposite directions. There is no correlation between the expression of nNOSmRNA and androgens (including T and DHT). Androgens give rise to penile erection probably not via the NOS pathway.

Androgens↗

PubMed2000

[Antituberculosis effect of levofloxacin].

OBJECTIVE: Assess the activities of levofloxacin (LVLX) against Mycobacterium tuberculosis both in vitro and in vivo, the pharmacokinetics of LVLX and the effectiveness and safety of it in the treatment of pulmonary tuberculosis, with ofloxacin(OFLX) as control. METHODS: The MIC and MBC of LVLX were determined by the tube doubling dilution method, and the effectiveness of the drugs were assessed by half survival time of the mice. The concentrations of LVLX and OFLX in serum were measured by HPLC. The pharmacokinetic parameters obtained were calculated. 138 newly diagnosed and retreatment pulmonary tuberculosis patients were randomly allocated to receive four chemotherapy regimens. RESULTS: The MIC and MBC of LVLX against Mycobacterium tuberculosis were 2 dilutions lower than that of OFLX, in a murine tuberculosis model, the antimycobacterial activity of LVLX was significant and superior to OFLX with the same dose. The concentration-time curves of LVLX and OFLX were conformed to an one-compartment model. There was no significant difference between the two formulations in the Tmax, T1/2 and 1/2 Cmax, 1/2 AUC of OFLX and LVLX. The sputum conversion rates at the end of treatments of groups I, II, III and IV were 97%, 97%, 82% and 84% respectively. X-ray resolution rates were 97%, 94%, 88% and 88% respectively. The side effects of four groups were rather low. CONCLUSIONS: LVLX displays powerful activities against Mycobacterium tuberculosis both in vitro and in vivo, which is two times that of OFLX.LVLX and OFLX have the same good pharmacokinetic characteristics. LVLX at the dose of 300 mg/d shows the same effectiveness and fewer adverse drug reactions in comparison with OFLX at the dose of 600 mg/d in the treatment of pulmonary tuberculosis. So LVLX is a new effective and safe antituberculosis drug.

Adolescent↗

PubMed2000

[A study on the changes of calcium signal in mast cells activated by antigen].

OBJECTIVE: To study the relationship between the calcium signal and activation of mast cells, laying the foundation for discovering a new potential theraputical target of signal transduction for type I anaphylactic diseases like asthma. METHODS: The fluorescent Ca2+ indicator Fluo-3 was used to observe and quantitate the calcium signal directly in activated RBL-2H3 mast cells by a flow cytometer and a confocal fluorescence microscope with laser. RESULTS: Antigens elicited significant increase in intracellular Ca2+ concentration ([Ca2+]i) and histamine release in sensitized cells, maximal [Ca2+]i increase being reached (525 +/- 42) nmol/L (n = 12) within 90-110 s after stimulation. Increase of fluo-3-fluorescence intensity was also observed with the confocal fluorescence microscope in cytosol. No significant increase of [Ca2+]i was observed after addition of EDTA in sensitized cells from an initial value of (79 +/- 3) nmol/L, to (80 +/- 4) nmol/L (P > 0.05, n = 12), but tyrosine phosphorylation was readily observed, and the indirect fluorescent intensity was significantly greater than that in the control group. No significant change of [Ca2+]i was observed with the addition of DNP-BSA after PMA (P > 0.05, n = 8). CONCLUSION: Calcium is involved in the activation process of mast cells stimulated by antigens.

Aniline Compounds↗

PubMed2000

[Mechanism of enhanced invasiveness of human hepatocellular carcinoma by integrin alpha 6 beta 1].

OBJECTIVE: To study the mechanism of enhanced invasiveness of human hepatocellular carcinoma (HCC) by laminin (LN) receptor integrin alpha 6 beta 1. METHODS: A stable transfectant of HCC Bel 7402 cell line, the alpha 6 beta 1 receptors of which were replaced by non-functional LN receptor alpha 6 beta 4-TR using dominant negative strategy, was used. Motility of the non-transfected, mock transfected and transfected tumor cells was assessed by the number of cells migrated to an area scratched out of cells on tumor cell monolayer. Tumor cell invasion was examined by cell penetration through a Matrigel layer in Boyden chamber. Matrix metalloproteinases (MMPs) secretion was detected by gelatin zymography. RESULTS: The migration of HCC Bel 7402 cells expressing dominant negative alpha 6 beta 1 was significantly decreased. Their invasive capability was decreased by 46.7%. The secretion of MMP-9 was almost totally inhibited and the activated MMP-2 was decreased by 43.9%. CONCLUSION: The decrease in cell motility, invasiveness and MMPs secretion of HCC cells expressing dominant negative alpha 6 beta 4 TR implies that LN-integrin interaction plays important role in HCC progression.

Carcinoma, Hepatocellular↗

PubMed2000

[MR myelography: analysis of 126 cases].

OBJECTIVE: To investigate the value and limitation of MR myelography (MRM) in depicting the spinal canal obstruction. METHODS: Heavily T2-weighted coronal MR myelography was performed with 3D fast-spin-echo (FSE) and fat-suppression sequence in 126 cases, including 6 cerebellomedullary cistern, 18 cervical, 19 thoracic and 83 lumbar cases. The resulting slice were then projected into a composite image using a standard maxium intensity projection (MIP) algorithm. RESULTS: 90.5% (114/126) of MRM yielded reproducible high-quality image of the spinal thecal sac. 106 lesions (extradural, intradural, intramedullary) were detected in 101 cases (80.2%). The level and degree of spinal canal obstruction were visualized and confirmed by operation in 66 cases with a high sensitivity of 100%, and a diagnostic accuracy of 91.3%. CONCLUSION: Heavily T2 FSE MR myelography is a noninvasive and reliable method. MRM surpasses conventional and CT myelography and could replace them in some degree.

Adolescent↗

PubMed2000

[Effect on keratocyte-mediated collagen degradation by Pseudomonas aeruginosa].

OBJECTIVE: To study the pathogenesis of cornea melting (ulceration) by pseudomona (P) aeruginosa for instruction of clinical treatment. METHODS: Type I collagen gels with or without suspended keratocytes were incubated for 24 hours under medium containing sterile P. aeruginosa culture broth. Native collagen fibrils were removed from the media by ultrafiltration. The ultrafiltrates were then hydrolyzed, and the amount of hydroxyproline was measured spectrophotometrically. The effect of a synthetic matrix metalloproteinase (MMP) inhibitor, Galardin, on collagen degradation was also examined. RESULTS: P. aeruginosa broth induced type I collagen gel degradation directly. In the presence of keratocytes, degradation by P. aeruginosa broth was enhanced. Galardin significantly reduced the amount of collagen degraded by P. aeruginosa culture broth, no matter keratocytes were present or not. CONCLUSION: P. aeruginosa culture broth directly degrades type I collagen and also increases keratocyte-mediated collagen degradation. The result is helpful to the clinical treatment of cornea melting caused by P. aeruginosa, and the mechanism should be further studied.

Animals↗

PubMed2000

[Combined triple/multi-surgery of vitrectomy-lensectomy and posterior chamber intraocular lens implantation].

OBJECTIVE: To study the feasibility and safety of the combined triple/multi-surgery of vitrectomy-lensectomy and posterior chamber intraocular lens implantation. METHODS: Triple/multi-surgery was performed on 32 eyes of 32 cases, including 29 cases of serious eye injuries of traumatic cataract, lens luxation, vitreous hemorrhage (some cases with intraocular foreign body, iris damage or iridodialysis), 1 case with lens nucleus dislocated into the vitreous cavity during the senile cataract surgery and 2 cases with intraocular lens luxated into the vitreous cavity postoperatively. RESULTS: After follow up for 1 - 14 months (mean 5.6 months), 15 cases had the best corrected visual acuity (BCVA) >or= 0.5 (46.9%), 11 cases had BCVA of 0.1 - 0.4 (34.4%), and 6 cases had BCVA < 0.1 (18.8%). There was an average of 2.10 DC of astigmatism after surgery. Macular edema was found in 14 cases (43.8%). CONCLUSIONS: The results suggest that the triple/multi-surgery be safe and feasible. The major causes affecting the postoperative BCVA are astigmatism and macular edema. Proper selection of indication and skillful manipulation are the key points of the combined surgery.

Adolescent↗

PubMed2000

[Epidemiological studies on the relationship between body weight and the prevalence rate of impaired glucose tolerance (IGT) in the population of urban areas of Tianjin city].

OBJECTIVE: In order to explore the relationship between body weight and the prevalence rate of IGT in a community - based population and to provide scientific informations of IGT for prevention and control. METHODS: Cluster sampling was carried out in prevalence survey, together with clinical examination and test of blood plasma glucose. RESULTS: A sample of 62,577 people was performed by cluster random sampling. Results showed that the crude prevalence rate of IGT in the whole population of three communities was 13.13 per thousand in males, 19.18 per thousand in females, and 16.23 per thousand in both sexes respectively. The IGT prevalence rate of different body weight group in community population had a marked difference. There was a trand that the IGT prevalence rate increased markedly with the increase of body weight. CONCLUSION: The incidence of IGT is related to body weight and obesity.

Adolescent↗

PubMed2000

[A study on incidence of injury and its socio-economic loss in children and young adults].

OBJECTIVES: To study the current status of incidence of injury among children and young adults and the causes of common injuries, and to estimate its socio-economic loss and extent of harmfulness. METHODS: Pupils in 19 primary and middle schools aged 7 to 18 years, totaling 14,533, were recruited with stratified cluster sampling during 1998 to 1999 in Guangzhou, Maoming, Jiangmen and Shantou. Judgement for injury was based on the following criteria: (1) diagnosed and treated in hospitals or school clinics, (2) a half-day off or more due to injury, and (3) emergency management by pupils' parents or teachers. RESULTS: There were 6 941 pupils suffered from varied injures during the year, with an incidence rate of 47.76% (50.08% for boys and 45.02% for girls). Incidence rate of injury was higher in the middle school pupils (13 - 18 years old, 58.49%) than that in the primary school pupils (7 - 12 years old, 40.08%). The incidence increased significantly with age, with a peak at ages of 13 - 15. Major causes of injuries resulted from falls, injury by sharp articles, collision, traffic injuries and burn/scalds, etc, which usually occurred due to carelessness in sports, playing, walking, bike-riding and working. Frequency of multiple injuries related to the educational level of parents and depended on whether or not an only-child in family. There were 2,173 injured pupils (accounting for 31.3% of the total) visited clinics or emergency department in hospitals and 627 (9.0%) hospitalized for treatment. Twenty-eight percent of the injured pupils were absent from school, with an average absenteeism of 5.6 days. There were 154 injured pupils with transient disability and 53 with permanent disability, with a disability rate of 410.47 per 100,000. Cost for their medical care averaged 81.5 yuan RMB per injured pupil. CONCLUSIONS: Injury was a common and frequently-happened incident among children and young adults and could seriously affect their health, development and growth, studying and their future of children and young adults. Health education, safety-promotion and removing hidden danger for injury are the major measures to prevent from injury, and the government and the whole society should pay great attention to injury issues in children and young adults.

Accidents↗

PubMed2000

[A brief history of the several missionary hospitals in the modern Anhui province].

In the modern Anhui province, the west missionary established clinics and hospitals to 74 in Anhui. There were four hospitals in those had been longer time and larger scale and more entirely manage system. It was larger influence for the formation and development of the modern Anhui western medicine. In the courses, the missionary - doctors promoted the spreading of the west medicine in the modern Anhui, but large quantities of Chinese doctors and nurses made with the activity contributes for these.

China↗

PubMed2000

[The effect of escharectomy during burn shock stage on the expression of ICAM-1 and TNF-alpha mRNA of rat pulmonary tissue].

OBJECTIVE: To study the rules of postburn expression of IGAM-1 and TNF-alpha and the rule of the change in the MPO activity in pulmonary tissue; to explore the influence of escharectomy on the changes in the above indices and to clarify the importance of escharectomy during shock stage. METHODS: One hundred and seventy six Wistar rats with 30% TBSA III degree back scald were used. RT-PCR was used in the examination of the expression of pulmonary tissue ICAM-1 and TNF-alpha mRNA and of the change in pulmonary MPO activity after escharectomy. RESULTS: The expressions of pulmonary ICAM-1 and TNF-alpha mRNA began to increase at 4 hour postburn and reached peak level at 12 and 24 hours postburn, respectively. Their expressions returned to near control level 96 hours postburn in rats undergone escharectomy during shock stage. On the contrary, they remained at a relative high level even on 7th postburn day in both non-operated rats and the rats receiving escharectomy 96 hours postburn. In addition, pulmonary tissue MPO activity fell to near control level in rats undergone escharectomy during shock stage, but it maintained a high level in rats in which escharectomy was not done during shock stage. CONCLUSION: These findings suggest that eschar could induce the production of endothelial adhesion molecules. Therefore escharectomy as early as possible is very important to prevent the expression and release of adhesion molecules and the development of SIRS.

Animals↗