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Biomedical subjects

K Li

Publications and source records attributed to K Li.

At least 271 records · Page 15Linked to original sources

Changes of mu opioid receptor binding sites in rat brain following electroacupuncture.

With [3H]-ohmefentanyl as a ligand, autoradiographic technique was used to observe the effect of electroacupuncture (EA) on mu opioid receptor binding sites in the brain areas related to pain modulation. The results were as follows: (1) The distribution of the mu receptor in the rat central nervous system was consistent in general with the results reported previously. (2) After EA of Tsu-San-Li, the mu receptor binding sites were increased significantly in the following examined structures: the caudate nucleus, septal nucleus, medial preoptic area, amygdalaoid nucleus, periaqueducal gray, interpeduncular nucleus, nucleus raphe magnus, and cervical and lumbar enlargements. The results indicate that EA is able to increase mu binding sites in the brain areas related to analgesia, suggesting the enhancement of mu receptor function by EA.

Animals↗

[Fixation of nonunion of pediatric middle and distal shaft of the femur with semicircular dynamic locked intramedullary nail].

From Oct. 1994 to Dec. 1996, 15 nonunions of pediatric middle and distal shaft of the femur due to previous osteomyelitis and pathologic fracture and/or failed internal fixation were treated with semicircular dynamic locked intramedullary nail (SDLIN). SDLIN was composed of a lateral and a medial nail, both of them were inserted into the medullary canal 1.5 cm above the epiphyseal line, and the tails were connected together by a bolt. All the 15 cases used iliac bone autograft for the defect. Follow-uped for an average of 16.3 months, all of them were healed in an average of 4.8 months, and excellent and good results were obtained in 86.7%. The results suggest that the SDLIN is effective and convenient for the fixation of the refractory nonunion of pediatric middle and distal shaft of the Femur.

Adolescent↗

[Effects of different intensity endurance training on hypothalamus-pituitary regulatory function].

Effects of different intensity endurance training on several main hormones related to exercise in the rat hypothalamus-pituitary-adrenal axis-gonadal axis were studied. The results indicated that different intensity endurance training played different roles in their synthesis and release. In 36 m/min training group, the reserve of beta-endorphine beta-EP, in hypothalamus-pituitary, the capacity of body stress and aerobic capacity were increased, whereas the stress level in exercise, the luteinizing hormone LH content were decreased as compared with other groups. It is suggested that proper endurance training may elevate the sports capacity in which beta-EP may play an important role in regulating adrenal axis and gonadal axis directly and indirectly.

Animals↗

[Study on adaptive changes of myocardial ultrastructure after endurance training at different intensities in rats].

The purpose of the investigation was to determine the adaptive changes of central mechanism of aerobic metabolism and to probe the best training intensity for developing the structure and function of heart most effectively. After endurance training at different intensities (including 26 m/min, 30 m/min, 36 m/min, 42 m/min) for 16 weeks, the rats were decapitated. Left ventricle were excised soon and were then processed for electron microscopy. Morphometry was performed at image analysis system. Quantitative analysis of ultrastructure of left ventricle and capillaries indicated that the best development of mitochondria inner membrane and cristea, the maximum improvement in number of capillaries, the most obvious enlarging of capillary cavity and the most remarkable shortening of maximum oxygen diffusion distance from capillary wall to the mitochondria appeared after training at the highest speed (42 m/min). It is demonstrated that after endurance training at different intensities the ultrastructure of all training groups showed good developments in varying degrees. Furthermore, endurance training at suitably high intensity could improve adaptation of myocardium most effectively.

Adaptation, Physiological↗

[Diagnosis and treatment of congenital choledochal cyst].

From January 1980 to June 1996, 82 patients with congenital choledochal cysts were treated and 76 of them were operated on B-ultrasonic diagnosis was made with a correct diaginostic rate of 93.9%. The total effective rate was was 78.4% after follow-up for 84 months. Resection of the cyst with Roux-Y hepaticojejunostomy was successful in 96.2% of the patients. Outer drainage was used as the first-aid measure. Cystoduodenostomy and cystojejunostoy which may lead to complications should be abandoned.

Adolescent↗

[Synthesis and antifungal activities of 1-(2-[(substituted-phenyl) methyl]thio)-2-(2,4-difluorophenyl)ethyl-1H-1,2,4-triazoles].

Twenty-one 1-[2-[[(substituted-phenyl) methyl] thio]-2-(2, 4-difluorophenyl) ethyl]-1H-1,2,4-triazoles were synthesized and 19 compounds are reported for the first time. Results of biological tests in vitro showed that the antifungal activities of all title compounds were better than or comparable to the activities of fluconazole. The antifungal activities of compounds 1-7 and 11-17 were better than or comparable to the activities of sulconazole. Compounds 1, 2 and 5 were 512 times more active than sulconazole against epidermophyton floccosum; compound 5 was 32 times more active against Candida albicans, compound 2 was 32 times more active against Sporotrichum schenckii; compounds 2 and 14 were shown to be 64 and 32 times more active against Cryptococcus neoformans; compounds 1 and 5 were 16 times more active against Aspergillus fumigatus.

Antifungal Agents↗

[Comparative molecular field analysis (CoMFA) of allylamine antimycotics].

Active analog approach has been applied to determine the pharmacophoric conformations of the allylamine antimycotics. Comparative molecular field analysis (CoMFA) has been used to establish 3D-QSAR of 48 allylamine antimycotics against six common human pathogenic fungi. Two different alignment rules were compared in the meantime. Five new synthetic compounds have been successfully employed to examine the predictive abilities of the CoMFA models against Trichophyton mentagrophytes and Aspergillus fumigatus.

Allylamine↗

[Preliminary study on oncogene MDM2 in acute leukemias].

OBJECTIVE: To explore the causes of MDM2 gene overexpression. METHODS: The amplification and overexpression of MDM2 gene in 41 acute leukemia patients and two leukemic cell lines (K051 and HL60) were studied by using Southern blot, dot hybridyzation and RT-PCR techniques. RESULTS: Overexpression of MDM2 gene was found in 51.2% (21/41) of the patients and HL60 cell line, but no amplification of the gene was found in all the patients and the two cell lines. CONCLUSION: The level of MDM2 gene expression was related to the prognoses of the patients but not to FAB subtypes of acute leukemias.

Actins↗

[Clonal analysis of blood cells using X-linked HUMARA gene polymorphism].

OBJECTIVE: To explore the method for clonal analysis of blood cells. METHODS: Thirty female AML patients and 20 normal female subjects were analysed by the analysis of X-linked HUMARA gene polymorphism and methylation pattern. RESULTS: The heterozygote rate of HUMARA gene in Chinese women was 88% and the gene had a stable methylation pattern. Out of 20 control females, 17 were heterozygotes and among them 15 were polyclonal, 2 (11.8%) showed skewed X-inactivation. All heterozygote AML were clonal hematopoiesis. CONCLUSION: HUMARA gene polymorphism is a good marker for clonality analysis of blood cells.

Adult↗

[HPLC determination of diltiazem in human serum and its pharmacokinetic parameters].

A simple and sensitive reversed-phase liquid chromatographic method has been developed and validated for the analysis of diltiazem in human serum and the study of pharmacokinetics of the drug in human body. Diltiazem and diazepam (internal standard) in serum were extracted with hexane-chloroform-isopropanol (60:40:5, V/V), and then measured by HPLC using a Spherisorb C18 column as stationary phase and a methanol-water triethylamine as mobile phase. Diltiazem was quantified by ultraviolet absorbance at 239 nm. The method proved to be linear in the clinical range of 15-300 microg/L with a regression coefficient of 0.9997. The lower limit of detection of diltiazem in serum was 3 microg/L. Intra-day and inter-day coefficients of variation of assay for diltiazem in serum were 3.5%-6.8% (n=7) and 6.2%-8.4% (n=5), respectively. The recoveries of diltiazem were 91%-104% for serum. The method has been used to determine diltiazem in serum samples from eight volunteers and provided data on the pharmacokinetics of the drug. The results inferred that diltiazem is absorbed rapidly and had a relatively short half-life time in healthy individuals. The data obtained was fitted with PKBP-N1 program on computer to study the pharmacokinetics. The results showed that the peak level in serum averaged 118.5 microg/L +/- 14.3 microg/L at 3.1 h +/- 0.4 h, and the areas under the drug concentration curves (AUC) was 793.1 microg x h/L +/- 83.1 microg x h/L.

Antihypertensive Agents↗

Cloning of the human type XVII collagen gene (COL17A1), and detection of novel mutations in generalized atrophic benign epidermolysis bullosa.

Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal variant of junctional epidermolysis bullosa (JEB). Previous findings have suggested that type XVII collagen is the candidate gene for mutations in this disease. We now have cloned the entire human type XVII collagen gene (COL17A1) and have elucidated its intron-exon organization. The gene comprises 56 distinct exons, which span approximately 52 kb of the genome, on the long arm of chromosome 10. It encodes a polypeptide, the alpha1(XVII) chain, consisting of an intracellular globular domain, a transmembrane segment, and an extracellular domain that contains 15 separate collagenous subdomains, the largest consisting of 242 amino acids. We also have developed a strategy to identify mutations in COL17A1 by use of PCR amplification of genomic DNA, using primers placed on the flanking introns. The PCR products are scanned for sequence variants by heteroduplex analysis using conformation-sensitive gel electrophoresis and then are subjected to direct automated sequencing. We have identified several intragenic polymorphisms in COL17A1, as well as mutations, in both alleles, in two Finnish families with GABEB. The probands in both families showed negative immunofluorescence staining with an anti-type XVII collagen antibody. In one family, the proband was homozygous for a 5-bp deletion, 2944del5, which resulted in frameshift and a premature termination codon of translation. The proband in the other family was a compound heterozygote, with one allele containing the 2944del5 mutation and the other containing a nonsense mutation, Q1023X. These results expand the mutation database in different variants of JEB, and they attest to the functional importance of type XVII collagen as a transmembrane component of the hemidesmosomes at the dermal/epidermal junction.

Adolescent↗

[Internal fixation with U-shaped pin in the treatment of fracture-dislocation of the cervical spine].

Twenty cases with fracture-dislocation of the cervical spine were treated by U-shaped pin fixation. The U-shaped pin made of Steiman pin was used to hold sublaminar fixation of two segments above and below the vertebra of fracture. When atlas or axis was injured, a pair of small holes were drilled on the occipitale. The closed end of the U-Shaped pin was wired through the holes. Early postoperative ambulation was allowed without external fixation. 18 cases were followed up for 8-35 months. 5 cases of six patients with neurologic deficits recovered completely. The remaining one improved, no failure or loosening of the U-Shaped pin or wires was observed. Sound union of the bone grafts was obtained in all the patients. The results suggest that the operative procedure is simple, with sound fixation and satisfactory reduction and union of the fractures.

Adolescent↗

[Development of three dimensional bone-connecting plate and its clinical application].

Biomechanical assessment showed that the three dimensional plate developed by the authors which had stereo-rigidity in the fixation of long bone fractures was superior to compressive plate and flanged plate in terms of anti-compressive and anti-torsional strength. The anti-bending strength was superior to the flanged plate but inferior to compressive plate. The comprehensive nature of the three dimensional plate remained superior. Clinical application in 112 cases with 85 of them being followed-up for 8-44 months showed that bone union occurred in 45-98 days. The average was 82 days. In 65 cases of them the plates had been removed. No delayed-union or non-union occurred. Preliminary experience showed that the three dimensional plate was a new design for the treatment of long bone fractures. It can be applied to various types of long bone fractures especially the severe comminuted fractures owing to its requirement of proper fixation.

Adolescent↗

Loss of heterozygosity on chromosome 6 in dichloroacetic acid and trichloroacetic acid-induced liver tumors in female B6C3F1 mice.

Dichloroacetic acid (DCA) and trichloroacetic acid (TCA) are major metabolites of tetrachloroethylene (PCE) and trichloroethylene (TCE) and are found in chlorinated drinking water. All four chlorinated compounds are liver carcinogens in B6C3F1 mice. It has previously been reported that approximately 20% of hepatic tumors induced by PCE exhibited loss of heterozygosity (LOH) on chromosome 6, suggesting the presence of a tumor suppressor gene. In the current investigation, we determined whether TCA or DCA also induced LOH on chromosome 6. Liver tumors were initiated in 15 day old female B6C3F1 mice with N-methyl-N-nitrosourea (MNU) and promoted with 20 mmol/l DCA or TCA in their drinking water. Twenty-four and thirty-seven liver tumors promoted by DCA and TCA, respectively, were examined for LOH using 4 polymorphic loci on chromosome 6. Ten of 37 (27%) tumors (7 of 27 carcinomas and 3 of 10 adenomas) promoted by TCA exhibited LOH at least for two loci on chromosome 6. All 10 tumors that exhibited LOH, lost the C57BL/6J allele at both the D6mit9 loci, while two also lost at least one of the C3H/HeJ alleles. No LOH on chromosome 6 was observed in the 24 liver tumors promoted by DCA. The LOH on chromosome 6 in TCA but not in DCA-promoted tumors supports it as an active metabolite of PCE and demonstrates different pathogenesis at least for some of the DCA and TCA-promoted liver cancer.

Animals↗