Biomedical subjects

T Y Li

Publications and source records attributed to T Y Li.

At least 19 recordsLinked to original sources

PubMed2004

Cadmium-induced colony disintegration of duckweed (Lemna paucicostata Hegelm.) and as biomarker of phytotoxicity.

The toxic effect of cadmium on Lemna paucicostata was investigated with hydroponic culture in a culture facility. Cadmium treatment (0.4-6.4 micromol L(-1) Cd) induced L. paucicostata to release daughter fronds from the mother frond before maturity, resulting in colony disintegration. The 8-h and 24-h EC(50) values for colony disintegration in L. paucicostata plants were 0.12 and 0.11 mg L(-1), respectively. The maximum permissible concentrations (MPCs) were 0.012 and 0.011 mg L(-1) accordingly (MPC = 10% x EC(50)). These values were lower than the values of most of these biomarkers in duckweed reported in the literature, suggesting that colony disintegration in L. paucicostata may serve as a sensitive biomarker for the phytotoxicity test. Nutrient concentrations (1/2, 1/10, 1/20, 1/40, and 0-fold concentrations of Hoagland's solution) and Cd salt form (CdCl(2) or CdSO(4)) did not have a significant effect on colony disintegration. In addition, resistance to Cd stress differed significantly among clones of the plants. Approximately 2% of colonies in the wild population of L. paucicostata were tolerant of cadmium. These results indicate that colony disintegration of L. paucicostata could be used as a sensitive, cost-effective, and valuable biomarker to assess the acute phytotoxicity of cadmium and other heavy metals.

Araceae↗

PubMed2000

Characterization of Aspergillus spores by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

The intact fungal spores of several strains of four Aspergillus species, Aspergillus flavus, A. oryzae, A. parasiticus, and A. sojae, were directly analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Very simple MALDI mass spectra are obtained by directly mixing spores with a matrix such as alpha-cyano-4-hydroxycinnamic acid or sinapinic acid. The mass spectra are obtained from the ablation of cell walls of spores owing to the acidity of the matrix solution. The MALDI results show that aflatoxigenic strains and non-aflatoxigenic strains have different mass peak profiles. Furthermore, the MALDI results of non-aflatoxigenic A. flavus and A. parasiticus spores resemble those of the closely related A. oryzae and A. sojae spores, respectively.

Aspergillus↗

PubMed2000

[Expression and characterization of HIV-1 Gag p17-p24 protein].

The biological and immunological characteristics of HIV-1 core protein p17-24 expressed by recombinant vaccinia viruses were studied. The results of indirect immunofluorescence assay (I-IFA), Western blot and dot ELISA showed that the two recombinants could express the p24 gag and p17-24 gag fusion proteins in infected cell lines respectively. The electromicroscope observation revealed that the expressed proteins could also assemble into virus-like particles. The recombinant vaccinia viruses can also stimulate mice for the formation of anti HIV-1 Gag p24 antibody. When infected with the recombinant viruses, the chromosome DNA ladder caused by the apoptosis of the BHK cell was observed.

Animals↗

PubMed2000

[Detection of EBV-DNA, EBNA2 and LMP-1 in tumor tissues of han and uygur patients with nasopharyngeal carcinoma in Xinjiang].

OBJECTIVE: To investigate the possible differences of human nasopharyngeal carcinogenesis between Han and Uygur patients in xinjiang. METHOD: Detection of EBV-DNA, EBNA2 and LMP-1 in tumor tissues of 73 patients (Han 41, uygur 32) with nasopharyngeal carcinoma (NPC) were performed by PCR and immunohistochemistry. RESULT: Tho positive rate of EBV-DNA, EBNA2 expression was 48.2%(20/41), 43.9% (18/41) in Han and 59.3%(19/32), 43.7%(14/32) in Uygur respectively, no significant difference was found (P > 0.05). Expression of LMP-1 in NPC, in both positive and negative EBV-DNA specimens, was higher in Uygur (78.9%) than that in Han (40%) (P < 0.05), CONCLUSION: The EBV infection may involve in nasopharyngeal carcinogenesis in xinjiang; the LMP-1 of EBV could be a more critical factor in malignant transformation of normal nasopharyngeal epithelium in uygur people than in han Chinese.

Adolescent↗

PubMed2000

[Pediatric intranasal and skull base needle endoscopic surgery and examination].

OBJECTIVE: To explore the values of the application of needle endoscope in pediatric nasal cavity and skull base surgery. METHOD: Using a kind of needle endoscope with the diameter of 1.9 mm and digital video image system, 8 cases of pediatric nasal cavity and skull base examination and surgery were performed. RESULT: Of 3 cases of congenital choanal atresia, one improved, the others recovered. One case (2.5 years old) of traumatic cerebrospinal fluid (CSF) fistulae was successfuly repaired under the 1.9 mm needle endoscope. There were 2 cases of congenital meningoencephalocele. One was 1 month newborn. When the diagnosis was confirmed by needle endoscopy and CT scan, the operation was postponed. The other got endoscopic operation and had recovered. Of 2 cases of skull base malignant tumour, the diagnosis was confirmed by intranasal biopsy under needle endoscope. CONCLUSION: With the application of needle endoscope, the pediatric skull base surgery and examination can be performed in the narrow nasal cavities and sinuses with less invasion and good result.

Cerebrospinal Fluid Rhinorrhea↗

PubMed2000

[Study on the association between interleukin-5 and eosinophil in nasal polyp].

OBJECTIVE: To explore the expression of IL-5 and its role in the formation and development of nasal polyp. METHOD: 31 patients with nasal polyp, 11 patients with chronic sinusitis(CS) and 6 control cases were chosen. Their IL-5 concentration in tissue homogenate were measured by ELISA. All patients with chronic sinusitis, control cases and 15 patients with nasal polyp were chosen to be counted eosinophils in their HE slice. RESULT: 1. The values of IL-5(pg/ml) in nasal polyp, CS and control group separately were: 23.44 +/- 6.68, 16.41 +/- 3.09, 12.86 +/- 4.17. IL-5 concentration in nasal polyp group was higher than that in the other two groups(P < 0.001). 2. The numbers of eosinophils in nasal polyp, CS and control group were 7.42 +/- 2.33, 1.30 +/- 0.59, 1.07 +/- 0.70 separately, the numbers of eosinophils in nasal polyp group were higher than that in CR or control group (P < 0.05). CONCLUSION: Nasal polyp is a disease characterized by eosinophilia, and IL-5 which activates eosinophil plays part role in the formation of nasal polyp.

Adolescent↗

PubMed1997

Phase I clinical trial of cefditoren pivoxil (ME1207). Tolerance in healthy volunteers.

A tolerance study to ME1207 was conducted in healthy volunteers using five single doses administered before a meal (50, 100, 200, 300 and 500 mg), a single 200 mg dose administered after a meal, and 200 mg administered every 12 h for 7 days. No subjective symptoms or changes in haematological and biochemical examinations and urinalysis were observed after single administration of 50 to 500 mg Four subjects complained of minimal upper abdominal discomfort when 200 mg was administered every 12 h for 7 days, but this symptom disappeared without remedial action in all cases. Therefore ME1207 was thought to be safe when orally administered at the above-mentioned doses by the above-mentioned administration methods.

Administration, Oral↗

PubMed1997

Phase I clinical trial of cefditoren pivoxil (ME 1207): pharmacokinetics in healthy volunteers.

Pharmacokinetics of ME1207 were evaluated in 5 groups of healthy adult male volunteers given single preprandial administration of 100, 200 and 300 mg; postprandial administration of 200 mg; and administration of 200 mg every 12 h for 7 consecutive days. Blood drug concentrations were determined by HPLC and bioassay after oral single administration of 100, 200 and 300 mg before meals. Serum concentrations and major pharmacokinetic parameters (Cmax, Tmax, AUC and T1/2 Ke) determined by these two methods were comparable. Cmax and AUC determined by bioassay after postprandial administration were greater than those determined after preprandial administration. Blood concentrations determined 1.5 and 12 h after each administration, during repeated administration of 200 mg every 12 hours for 7 days, were always about 2.5 and 0 mg/l, respectively, indicating that the drug is not accumulated in the body. Within 24 hours after administration of 100, 200 and 300 mg, 19.93 +/- 5.20, 20.24 +/- 3.72 and 21.29 +/- 5.47%, respectively, of the dose were excreted into urine in an unchanged form.

Absorption↗

PubMed1994

Effects of selenium and alpha-tocopherol on liver damage induced by feeding grains from an endemic area of Keshan disease in rats.

Previous studies have shown the pathogenic effects of grains cultivated in the endemic areas of Keshan disease and selenium is effective in the prevention of this disease. In this study, liver damages induced by feeding grains from an endemic area (endemic diet), and the effects of selenium and alpha-tocopherol supplement were examined. After 3 months on the endemic diet, the amounts of serum enzymes were significantly increased when compared to controls (animals receiving diet from a non-endemic area). Liver enzymes (alkaline phosphatase and choline esterase) were also found to be altered in the serum, further suggesting liver damages in animals on an endemic diet. Supplement of the endemic diet with selenium or alpha-tocopherol reversed the changes in serum enzymes. Increase in lipid peroxidation in the liver of animals on the endemic diet was observed when compared to that in control animals. Selenium and alpha-tocopherol supplements prevented the increase in lipid peroxidation in the liver by the endemic diet. Semi-quantitative histochemical analysis of glutamate dehydrogenase and succinate dehydrogenase in liver tissue showed that the livers of animals on an endemic diet were more sensitive to ischemic damages in vitro. Supplementation of the endemic diet with either selenium or alpha-tocopherol reduced the sensitivity to ischemic damages. The results suggest that increased lipid peroxidation in the liver of rats on an endemic diet may be responsible for liver damages and elevation of serum enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Insect resistance of transgenic tobacco plants expressing delta-endotoxin gene of Bacillus thuringiensis.

The initiative B.thuringiensis delta-endotoxin (Bt toxin) gene clones TH12 and TH48 contain two different classes of homologous genes, the 5.3 kb class and 6.6 kb class, respectively. Bt toxin genes of both classes, modified at the 5'-end and truncated at the 3'-end, can still be expressed to produce the insecticidal, truncated toxin proteins in E. coli. The modified Bt toxin genes were inserted into the plant binary expression vector pBin 437 (a derivative plasmid of pBin 19) and were transferred into tobacco by Ti plasmid-mediated gene transfer system. Southern blot and DNA slot blot analysis indicate that the Bt toxin genes have been integrated into tobacco genome at a copy number of 1 to 5. Northern blot analysis of polyA+ RNAs from progeny of the transgenic plants revealed that Bt toxin genes of both 5.3 kb and 6.6 kb classes were expressed in transgenic plants, though the transcripts were degraded to RNAs of lower molecular weights. In insecticidal test, 5 plants from the progeny of 5.3 kb class gene-transformed SR1 tobacco plants and 3 plants from those of 6.6 kb class gene-transformed plants were found to be toxic to the testing larvea of H.assulta. In comparison with the control, mortality of the insects fed on transgenic plants reached 40-50% and the growth of the survived insects was remarkably inhibited. These results indicate that the modified Bt genes of the 5.3 kb and 6.6 kb classes were expressed in transgenic plants and could confer on the transgenic plants a new character of insect resistance.

Animals↗

PubMed1989

[CT diagnosis of pulmonary solitary nodule--a correlative study of CT, X-ray and pathology].

A correlative study of CT, X-ray and pathology was done on 41 cases with pulmonary solitary nodule, including peripheral lung cancer 30 cases, benign lesion 10 and metastatic tumor 1. Results showed that CT was more sensitive than conventional X-ray in depicting the characteristic signs such as spiculate protuberance, minute calcifications, small vacuole sign and retraction of pleura. 2 mm thin slice CT scanning is helpful in differential diagnosis of lesions less than 2 cm in diameter. Correlation of CT findings with pathology indicated that spiculate protuberance was caused by infiltrative growth of tumor, whereas the small vacuole sign represented remnant of air containing cavity or slit. The shaggy border of inflammatory nodule was the result of extension of inflammatory process. A correct diagnosis of pulmonary solitary nodule lies in comprehensive analysis of CT manifestations. There is greater possibility of malignancy with mass greater than 4 cm in diameter, lobulation and spiculation are frequently present. Lung cancer less than 3 cm in diameter often presents as lobulated mass with spicules, small vacuole sign and pleural retraction.

Diagnosis, Differential↗

PubMed1988