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Biomedical subjects

T Li

Publications and source records attributed to T Li.

At least 451 records · Page 25Linked to original sources
PubMed1995

Long-term effect of leprosy control in two Prefectures of China, 1955-1993.

In Weifang Prefecture, Shandong Province, and Wenshan Prefecture, Yunnan Province of China, leprosy was highly prevalent in the 1950s. Due to differences in geographical conditions and socioeconomic development, the decline in leprosy prevalence between 1955 and 1993 was 99.5% (10.1 to 0.05/10,000) in Weifang and 93.9% (19.7 to 1.2/10,000) in Wenshan. The decrease in the detection rate was 99.9% (35.2 to 0.05/10,000) in Weifang and 91.7% (69.9 to 5.8/10,000) in Wenshan. The decrease was more apparent in these two prefectures since the implementation of multidrug therapy (MDT) in 1986. Findings such as specific detection rates by age, sex and type, as well as the multibacillary, child, and deformity rates of patients detected since 1980 were studied. Using the detection and prevalence rates between 1980 and 1993, the number of patients until the year 2000 is extrapolated for these two prefectures.

Adolescent↗
PubMed1995

[Influence of heating degrees on appearance of calcined shell drugs].

The colors, crisp extents and comminution rates of 4 kinds of shell drugs calcined under various conditions were conpared systematically. The appearance alterations of the calcined drugs were closely related to the heating degrees during calcining operation, and the effect of calcining duration was greater than that of calcining temperature.

Animals↗
PubMed1995

[Influence of heating degrees on internal quality of calcined shell drugs].

The internal quality of 4 kinds of shell drugs calcined under different conditions was investigated and compared in terms of the yielding ratios and total calcium content of the calcined product, Ca2+ content of the decoction and total water-soluble extractive rate. It was found that at calcining temperatures higher than 800 degrees C the internal quality of the shell drugs would change markedly.

Animals↗
PubMed1995

[The use of thin skin flap with preserved subdermal vascular network in repair of the face and neck].

Since 1989 twenty-one thin flaps with preserved subdermal vascular network of the neck, shoulder or pectoral region have been used in 18 cases with severe scar contracture of the neck. The size of the flaps ranged from 10 cm x 2 cm to 20 cm x 8 cm and the pedicles were 3.5 to 4 cm in width. Our results proved the reliability of this method. The blood supply of the flap, the design and indications of the operation are discussed.

Adolescent↗
PubMed1995

Reaction of hydroxyapatite-sol in bone marrow.

Hydroxyapatite-sol was prepared by dispersing hydroxyapatite microcrystals into saline. The hydroxyapatite microcrystals were synthesized by neutralization reaction of calcium hydroxide suspension and phosphoric acid solution. Sizes of the hydroxyapatite microcrystals were less than 0.1 microns, and the mean value was 0.05 microm. The 0.2 ml hydroxyapatite-sol with a concentration of 14.8 mg/ml was injected into medullary cavities of rat femurs. Both sintered hydroxyapatite powder suspension and saline as comparative materials were injected into the medullary cavities in the same way. Reaction of the hydroxyapatite-sol in the bone medullary cavities was investigated histologically using light and transmission electron microscopes. After 3 days, new bone formation was observed by injection of hydroxyapatite-sol, while no bone formation was observed by injection of sintered hydroxyapatite powder and saline. Osteoblasts were observed endocytosing the hydroxyapatite-sol in the medullary cavities of the rats. Macrophages and undifferentiated osteoblasts were found around the hydroxyapatite-sol aggregation by transmission electron microscope. After 5 days, amounts of new bone increased and matured, forming trabeculae. Many osteoblasts were observed in a line along the surface of the bone. On the other hand, 5 days after injection of sintered hydroxyapatite powder and saline to bone formation was observed while at 10 days after injection, some immature new bone formation started to be observed. New bone increased and matured at 15 days postoperatively. From these results, it was concluded that hydroxyapatite-sol only quickly promotes the formation of new bone in bone marrow and can be used as injection liquid of new biomaterials for bone formation.

Animals↗
PubMed1995

[p53 gene deletion and abnormal expression in gastric carcinoma].

We studied p53 gene at the DNA and protein level in human gastric cancer tissues and corresponding normal gastric mucosae from 20 cases of patients undergone radical surgery. By Southern blotting, the p53 gene was found to be partially deleted in 30% (6/20) of gastric cancer tissues. ABC immunohistochemical study of p53 expression was carried out on cryostat sections using monoclonal antibodies (PAb 1801) to p53. High level expression of mutated p53 protein was detected in 55% (11/20) gastric cancer tissues. The staining pattern was intranuclear and/or intracytoplamic. There was no detectable staining of any of the normal gastric tissues with 1801 antibody. The positive rate of p53 overexpression was higher in poorly-differenciated glandular carcinomas than well-differenciated cancer (P = 0.0116). Highly significant association exists between high level p53 expression and allele deletion (r = 0.59). The date indicate that inactivation of p53 gene is important in human gastric carcinogenesis and tumor progression. The assay of p53 gene structure and products may provide new biologically relevant tumor marks for predicting the behavior of gastric carcinomas, identifying more aggressive tumors, determining prognosis of the patients and guiding treatment.

Adenocarcinoma↗
PubMed1995

[Determination of primaquine and hepatic targeting neoglycoalbumin-primaquine in whole blood and liver of mouse by normalphase high-performance liquid chromatography].

We have developed a method to estimate primaquine (PQ) and hepatic targeting antimalarial agent neoglycoalbumin-primaquine (NGA PQ) in whole blood and liver of mice by sensitive and selective high-performance liquid chromatography. The primaquine was extracted out with ether from the basified biological samples in the PQ diphosphate group or from the samples which were acidic hydrolyzed then basified in NGA-PQ group. The extracts were evaporated under N2 then dissolved in the mobile phase. A linear chain analogue of primaquine was used as the internal standard. The samples were injected into the normal phase silica column with chloroform: methanol:ammonia solution (86.8:12.5:0.7,V/V/V) as mobile phase and detected at 254 nm. The average recovery of the method was 100.09 +/- 3.46 (mean +/- s)%; the CV of within-day and between-day were 2.7%-6.13% (n = 5) and 8.32%-13.56% (n = 9) respectively; in PQ group and NGA-PQ group, the PQ concentrations ranged from 10-20,000 ng/ml blood or 1g. liver respectively, and they all yielded a good linear relationship with the peak height ratios. No endogeneous interference was found in chromatograms of biological samples.

Animals↗
PubMed1995

[Inhibition of antisense DNA and its derivative on gastric transformed cell carcinogenicity].

In this study, an antisense c-Ha-ras DNA was synthesized. It was a complementary oligonucleotide chain to the sequence of initiation position of c-Ha-ras gene transcription. We found that the antisense DNA blocked the gene expression at the level of transcription and translation and partially reverted the malignant phenotyped of gastric transformed cells, including their growth rate, colonies formation in soft agar, tumorigenicity in nude mice and different grade. When the 5'-end of the antisense DNA was covalently linked with psoralen group, its biological effects were significantly enhanced. No effect of tumor inhibition was found in control oligonucleotide chains not complete complementary to the sequence of target gene. These results indicate that antisense DNA and its derivative are effective in tumor gene therapy.

Animals↗
PubMed1995

[Effect of lipid peroxide on lymphocytes and its role in postburn immunosuppression].

PURPOSE: Mechanisms of postburn immunosuppression are complicated and remain unclear. In the present experiment the effect of linoleic acid hydroperoxide (LOOH) on lymphocytes was evaluated in vitro, and then the changes in postburn lipid peroxide (LPO) levels and lymphocyte functions were measured, in order to investigate the mechanism of immunosuppression following burn. METHODS: Proliferation and IL-2 production and LPO of lymphocytes were assayed after the incubation with LOOH for in vitro study. On day 6 after induction of 11%-12% TBSA full-thickness burn, the animals were sacrificed, and proliferation and IL-2 production of splenic lymphocytes, LPO levels of the plasma, livers and spleens were measured. RESULTS: LOOH inhibited proliferation and IL-2 production and induced lipid peroxidation of lymphocytes in vitro, and Vit E could attenuate the effects of LOOH. LPO levels increased and proliferation and IL-2 production decreased after burn, but those changes in Vit E or SOD group showed no statistical significance compared with normal control group. CONCLUSION: Enhancement of lipid peroxidation and increased LPO after burn may be one of the mechanisms of postburn immunosuppression.

Animals↗
PubMed1995

[Effect of tetrandrine on pulmonary hypertension induced by monocrotaline in rats].

The effects of Tetrandrine (Tet) on intraacinous pulmonary arteries (IAPA) and bemodynamics were studied by means of a rat pulmonary hypertension model induced by monocrotaline. The results showed that Tet could reduce the contractive pressure of pulmonary artery, right ventricle and right atrium of heart by 28.0%, 28.3%, and 31.5% respectively. It could also decrease the vascular degeneration of endoepithelial cells of IAPA, the endoepithelial subcavity, the collagens of medial membrane and the numbers of smooth muscles of IAPA.

Alkaloids↗
PubMed1995

The synthesis and biological activities of oligodeoxynucleotides that are covalently linked to psoralen at their 5' ends.

Four oligodeoxynucleotides (15-mers), designated 13 through 16, and the corresponding conjugates, designated 17 through 20, in which psoralen was covalently linked to the 5' end of each oligonucleotide were synthesized. Compounds 16 and 20 contained a sequence that was complementary to part of the first four codons and the upstream sequence close to the ribosome-binding site of c-Ha-ras mRNA. Compounds 16 and 20 inhibited the growth of cells that had been transformed by the c-Ha-ras plasmid, with accompanying suppression of the expression of the activated c-Ha-ras oncogene. The antisense oligonucleotides 16 and 20 also appeared to cause partial reversion of the major phenotypic characteristics of transformed cells, which included inhibition of anchorage-independent growth. Compound 20, which contained psoralen, was a more efficient inhibitor of the growth of transformed cells than compound 16 without psoralen, a result that suggests psoralen might have increased the ability of the oligodeoxynucleotides to enter the cells.

Amino Acid Sequence↗
PubMed1995

[Analysis of genetic properties of meiotic products from an interspecific triploid fusion-hybrid itself constructed by protoplast fusion in Saccharomvces].

A genetically stable interspecific triploid fusion-hybrid between a diploid Saccharomyces cerevisiae var. ellopsoideus and a haploid Saccharomyces diastaticus was constracted by protoplast fusion technique. Experimental results indicate that such hybrid can be induced to sporulate as a sexual hybrid. Genetic analysis of the complete and non-complete tetrads demonstrates that the prototrophic interspecific triploid fusion-hybrid HU-KDF-240 selected by nutritional complementation experienced segregation and exchange for the genetic markers, and showed parental ditype and recombination in the meiotic process of sporulation. The results of the tetrad analysis of the hybrid HU-KDF-240 showed a 1:2 segregation ratio for soluble starch fermenting and non-fermenting characters and a 1:1 segregation ratio for genetic markers of the auxotrophic character in 349 complete and non-complete tetrads from 186 asci of the hybrid.

Cloning, Molecular↗
PubMed1994

Identification of the iron-carbonyl stretch in distal histidine mutants of carbonmonoxymyoglobin.

Soret-excitation resonance Raman (RR) spectra are reported for six distal histidine mutants of carbonmonoxymyoglobin including H64A, H64V, H64L, H64I, H64W, and H64W/L29F. Based on 13CO isotope shifts, the iron-carbonyl stretching vibrations are unambiguously identified. The correct assignment of these modes eliminates the differences in the conformational substate occupations predicted by the RR versus IR data.

Binding Sites↗