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Biomedical subjects

Q Li

Publications and source records attributed to Q Li.

At least 307 records · Page 17Linked to original sources
PubMed2000

Usefulness of postischemic thrombolysis with or without neuroprotection in a focal embolic model of cerebral ischemia.

OBJECT: Recent studies have shown that the use of thrombolysis in the setting of acute stroke is associated with an increased risk of cerebral hemorrhage. The time of onset of symptoms to initiation of medication and the dose levels of the thrombolytic agents are important determinants for the risk of cerebral hemorrhage. The authors evaluated the time course of thrombolysis-related hemorrhages in experimental settings and tested whether the addition of neuroprotective medication augments the efficacy of thrombolysis and reduces the incidence of hemorrhages. METHODS: Male Wistar rats were subjected to right middle cerebral artery embolization with an autologous thrombus and were then randomly assigned to one of the following groups: Group 1, saline-treated (2 hours after ischemic insult) animals as controls; Groups 2 to 4, high-dose urokinase (5,000 U/kg) at 2, 3, and 6 hours after the insult; Group 5, low-dose urokinase (2,500 U/kg) at 2 hours after the insult; Group 6, 20 mg/kg topiramate (TPM) at 2 hours after the insult; Group 7, a combination of 20 mg/kg TPM at 2 hours and low-dose urokinase (2,500 U/kg) at 6 hours after the insult; and Group 8, 20 mg/kg TPM (20 mg/kg) at 2 hours and high-dose urokinase (5,000 U/kg) at 2 hours after the insult. Neurological behavior and the infarct volume in the brain were assessed following cerebral embolism and the various treatments. All animals in the single therapy and low-dose combination groups survived surgery. Three of eight animals treated with high-dose urokinase alone at 6 hours and three of six animals in the combined high-dose urokinase and TPM group developed fatal intracerebral hemorrhages. There was a significantly better neurological outcome at 24 hours in the animals treated with either medication compared with controls. The volume of the infarct in the saline-treated group was 54.2 +/- 9%. The use of TPM at 2 hours led to a decrease in the infarct to 20.1 +/- 11.2% (p < 0.01). Treatment with urokinase at 6 hours after the occlusion showed a trend toward protection; the infarct volume was 31.9 +/- 14.1% (p < 0.05). The addition of TPM to low- or high-dose urokinase achieved better neuroprotection (8.2 +/- 6% and 11.9 +/- 10.7%, respectively; both p < 0.01). CONCLUSIONS: In this study the authors show that the volume of the infarct can be significantly decreased with 2 to 6-hour delayed intraarterial thrombolysis with urokinase and that the efficacy of thrombolysis may be enhanced by combining neuroprotective agents like TPM. It is also shown that low-dose combination therapy may decrease the likelihood of cerebral hemorrhage.

Acute Disease↗
PubMed2000

Comparison of two human ovarian carcinoma cell lines (A2780/CP70 and MCAS) that are equally resistant to platinum, but differ at codon 118 of the ERCC1 gene.

ERCC1 is an essential gene within the nucleotide excision repair process. We studied two human ovarian carcinoma cell lines for cisplatin resistance, which differed with respect to ERCC1. The A2780/CP70 cell line has been extensively studied previously, and has the wild-type ERCC1 sequence. The MCAS cell line has a recently described ERCC1 polymorphism at codon 118, which is associated with an approximate 50% reduction in codon usage. These cells did not differ with respect to p53 sequence nor p53 mRNA induction following cisplatin exposure. The induction of ERCC1 mRNA was markedly reduced in MCAS cells as compared to A2780/CP70 cells. At the IC50 cisplatin dose for each cell line, MCAS cells were less proficient at cisplatin-DNA adduct repair than A2780/CP70 cells. In absolute terms, A2780/CP70 cells repaired 3-fold as much adduct (2.7 pg/microgram DNA over 6 h vs 0.86 pg/microgram DNA); and when expressed in terms of the maximal DNA adduct load, A2780/CP70 cells repaired 50% more adduct than MCAS cells. MCAS cells had increased cytosolic inactivation of drug at the IC50 dose level, which has been previously suggested to be a compensatory cellular response for reduced DNA repair capacity. These data suggest the possibility that this specific ERCC1 polymorphism, may be associated with reduced DNA repair capacity in human ovarian cancer cells. This association may be effected through a reduction in peak production of ERCC1 mRNA, and a consequent reduction in the translation of ERCC1 mRNA into protein.

Antineoplastic Agents↗
PubMed2000

Evaluating gene x psychological risk factor effects in the pathogenesis of anxiety: a new model approach.

The present study evaluated the singular and interactive effects of a functional polymorphism (variation) in the serotonin transporter (5-HTT) gene and a psychological trait (anxiety sensitivity [AS], i.e., fear of arousal symptoms) in predicting subjective and physiological responses to a 35% carbon dioxide (CO2) challenge in a community sample (N = 72). Genotypes were divided into 2 groups in accord with prior research. Findings were partially supportive of the hypothesized risk model. These indicated that the Group L genotype (homozygous for the 1 allele), compared with the Group S genotype (homozygous for the s allele plus heterozygous individuals), predicted greater fearful response to the biological challenge. There was also an AS x Genotype interaction predicting heart rate variability (HRV) in response to the CO2, suggesting that high AS plus Group L status predicts decreased HRV.

Administration, Inhalation↗
PubMed2000

[Expression and plasma activity of plasminogen activator inhibitor-1 infibrotic liver tissues].

OBJECTIVE: To study plasminogen activator inhibitor-1 (PAI-1) gene expression and protein synthesis in fibrotic liver tissues and plasma activity levels. METHODS: Plasma PAI-1 activity was detected by chromogenic activity assay kit. The messenger RNA (mRNA) of PAI-1 and PAI-1 protein was detected on serial biopsied liver specimens of normal, HBV-related chronic hepatitis and cirrhosis by in situ hybridization and immunohistochemistry. The semi-quantitative results of the protein expression to immunohistochemistry staining were analysed in contrast with the stage of hepatic fibrosis. RESULTS: The plasma PAI-1 activity levels decreased with the progression of hepatic fibrosis. PAI-1 mRNA and protein were expressed in the extracellular matria deposition of the portal areas, focal necrotic areas, fibrous septa and hepatocytes as well as the hepatocellular cytoplasm adjacent to the areas described above. CONCLUSION: Localization of PAI-1 is not only in interstitial cells but also hepatocytes, suggesting an intense relationship between PAI-1 and hepatic fibrosis.

Adolescent↗
PubMed2000

Ontology acquisition from on-line knowledge sources.

Electronic knowledge representation is becoming more and more pervasive both in the form of formal ontologies and less formal reference vocabularies, such as UMLS. The developers of clinical knowledge bases need to reuse these resources. Such reuse requires a new generation of tools for ontology development and management. Medical experts with little or no computer science experience need tools that will enable them to develop knowledge bases and provide capabilities for directly importing knowledge not only from formal knowledge bases but also from reference terminologies. The portions of knowledge bases that are imported from disparate resources then need to be merged or aligned to one another in order to link corresponding terms, to remove redundancies, to resolve logical conflicts. We discuss the requirements for ontology-management tools that will enable interoperability of disparate knowledge sources. Our group is developing a suite of tools for knowledge-base management based on the Protégé-2000 environment for ontology development and knowledge acquisition. We describe one such tool in detail here: an application for incorporating information from remote knowledge sources such as UMLS into a Protégé knowledge base.

Artificial Intelligence↗
PubMed2000

Antagonistic effects of 3 sesquiterpene lactones from Atractylodes macrocephala Koidz on rat uterine contraction in vitro.

AIM: To study the effects of three sesquiterpene lactones: atractylenolide I (8,9-dehydroasterolide, B), 4,15-epoxy-8 beta-hydroxyasterolide (C), and atractylenolide III (8 beta-hydroasterolide, D) from Atractylodes macrocephala Koidz, on rat isolated uterus smooth muscle. METHODS: Rat isolated uteri bathed in De Jalon I solution were used; acetylcholine (ACh), CaCl2, and oxytocin (Oxy) were used to evoke the contraction of uterus. RESULTS: B, C, and D 28 or 56 mumol.L-1 inhibited the spontaneous movement of uterus, reducing their rest force, contractile force, and movement ability. B 28 or 56 mumol.L-1 also slowed down the frequency of uterus spontaneous contraction, but C or D did not. B, C, or D 28 and 56 mumol.L-1 inhibited the uterine spasm induced by Oxy and ACh. Likewise, Ver 0.28 mumol.L-1, B, C, and D 28 or 56 mumol.L-1 relieved the contraction mediated by CaCl2 in high-KCl solution, but B, C, or D had not marked influence on the maximal response of uterus to CaCl2. CONCLUSION: B, C, and D inhibit the movement of uterus smooth muscle, and the mechanism is related to the inhibition of cholinergic system as well as Ca2+ movement.

Acetylcholine↗
PubMed2000

[Functional reconstruction of the hand after electrical injury with a composite flap of the vessel nerve and fascia].

OBJECTIVE: In the case of electrical injury of the wrist, it may be necessary to transplant a long tendon, nerve and vessel for functional reconstruction. But the fibrosis of the recipient bed often makes the survival and functioning of the grafts difficult. This clinical study was to solve the problem. METHODS: A composite flap was designed consisting of the small saphenous vein, the sural nerve and the fascia of the lower-leg. The small saphenous vein and the nerve were transplanted to repair the defects of the radial or ulnar artery and the media nerve. The fascia was used to reconstruct the recipient bed for tendon grafting. RESULTS: Six cases were treated with this method with success in 5 cases. 5 to 18 months' follow-up revealed restoration of sensation and finger flexion in the 5 cases. CONCLUSION: This method is effective in alleviating tendon adhesion, accelerating functional restoration of the injured hand.

Adolescent↗
PubMed2000

[Effect of elevated CO2 concentration on growth of dominant tree species in pine broadleaf forest of Changbai mountain].

Potted saplings of Pinus koraiensis, Picea koraiensis, Larix olgensis, Populus ussuriensis, Betula platyphylla, Tilia amurensis, Traxinus mandshurica, and Acer mono, the eight dominant species in the Korean pine broadleaf forest at Changbai Mountain, were grown in open-top chambers with ambient(400 microliters.L-1) and elevated (700 microliters.L-1) CO2 concentration under natural sunlight for two growing seasons. The average height growth of these eight species under elevated CO2 increased by 10%-40%, compared with the control at ambient CO2. The response of transpiratory rate to the higher CO2 concentration was different among the species, and the water use efficiency of the saplings of the 8 species growing under elevated CO2 concentration was higher than that under ambient CO2. Soluble sugar and chlorophyll contents were not related to the CO2 concentration under which the saplings grew, indicating that the complicacy was existed in the acclimation of tree species to high CO2 concentration. The response of broad-leaved tree species to the elevated CO2 concentration was more sensitive than that of conifer tree species. Saplings of all tree species showed a photosynthetic acclimation to higher CO2 under long-term elevated CO2 concentration.

Carbohydrate Metabolism↗
PubMed2000

[Advances in diagnosis and treatment of ectopic pregnancy during the past ten years].

OBJECTIVE: To investigate the changes of diagnosis and treatment of ectopic pregnancy (EP) during the past ten years. METHODS: Medical records of 1,970 cases with EP seen in our hospital from Jan. 1987 to Dec. 1996 were collected and analyzed retrospectively. RESULTS: (1) The incidence of EP increases from 1.0 per 42.4 labours during 1987-1988 to 1.0 per 6.6 labours in 1995-1996. (2) Diagnosis was confirmed more by television laparoscopy, transvaginal ultrasonography and sensitive human chorionic gonadotropin-beta subunit assay rather than loparotomy and with a shorter period, (6.5 +/- 0.7) days in 1987-1988 versus (3.7 +/- 0.2) days in 1995-1996. (3) The choice of treatment was more conservative or through laparoscopic surgery than abdominal salpingectomy. (4) The success rate of conservative surgery expectant management reached 100.0% and medical treatment with a variety of choices around 80.0%-85.%. CONCLUSIONS: Although the incidence of EP increased, with the improvement of diagnostic approaches, patients were detected at an earlier stage and possible to be treated more conservatively.

Female↗
PubMed2000

[WHO sample survey on drug resistant tuberculosis in Zhejiang, China].

OBJECTIVES: To obtain the data on initial and acquired drug resistance, and to evaluate the efficacy of ongoing tuberculosis (TB) control strategies. METHODS: According to the Guidelines for Surveillance of Drug Resistance in Tuberculosis of WHO/IUATLD, randomly selected 30 counties with population proportionate cluster sampling method. Proportion method was used for drug sensitivity test, laboratory quality control was done by Korean super-country reference laboratory. RESULTS: 1,013 TB patients were enrolled in 30 counties, 954 were culture positive, and one with non-tuberculous mycobacteria. The culture positive rate was 94.6%, the contaminated rate was 3.2%. Drug susceptibility testing against streptomycin (SM), isoniazid (INH), rifampicin (RFP) and ethambutol (EMB) were performed in 953 cases, the total drug resistant rate was 21.5%, the initial drug resistant rate was 14.8%, the initial multi-drug resistance was 4.4%, the acquired drug and multi-drug resistant rates were 59.0% and 34.7%, respectively. CONCLUSIONS: The initial drug resistant rates were decreasing in comparison to 1990 (24.0%), suggesting good effect of DOTS policy implemented in Zhejiang province. However, multi-drug resistant rate was higher in this province than some other countries, indicating more attention should be paid to this situation.

Anti-Bacterial Agents↗
PubMed2000

[Micro-anatomy of the apical lateral foramina of permanent teeth].

OBJECTIVE: To provide data of apical lateral foramina of Chinese people's permanent teeth. METHODS: The shape and diameter of the apical lateral foramina in 1,502 permanent teeth were observed under the XTL-2 stero-microscope. RESULTS: The shape and diameter of 230 apical lateral foramina in the permanent teeth can be divided into four types: round (61.31%, diameter: 0.09-0.26 mm), oval (36.96%, diameter: 0.12-0.28 mm), renal (1.30%), and irregular (0.43%). The occurrence of the apical lateral foramina is 15.31% (230/1,502). CONCLUSIONS: The apical lateral foramina are found in 1/7 of 1,502 permanent teeth.

Dental Pulp Cavity↗
PubMed2000

[Observation on dynamic changes of serum procollagen III, hyaluronic acid and laminin in rats with hepatic fibrosis treated with Hujin pill].

OBJECTIVE: To study the dynamic changes of serum procollagen III (PCIII), hyaluronic acid (HA) and laminin (LN) in rats with hepatic fibrosis treated with Hujin pill (HJP). METHODS: The classic model of hepatic fibrosis induced by CCl4 were used in the observation. The serum PCIII, HA and LN were determined by radioimmunoassay (RIA). RESULTS: HJP could reduce the serum HA, LN content significantly, as compared with the control group, the difference was significant (P < 0.05, P < 0.01). Its long-term therapeutic effect was better than that of colchicine. It could maintain the serum PCIII stable in hepato-fibrotic stage (9-12 weeks), as compared with the normal control group, the difference was insignificant (P > 0.05). CONCLUSION: HJP could retard the liver fibrosis, and has good preventive and therapeutic effect on liver fibrosis in rats.

Animals↗
PubMed2000

[Changes of blood circulation of the extremity with tibia shaft defects treated with external fixation].

OBJECTIVE: To study external skeletal fixation for long tubular bony defect by end to end compression with lengthening (EECL) and segmental bone transport by lengthening (STBL). METHODS: About 20% - 30% of the original length was resected from the middle shaft of the tibia in 10 goats of 1 - 2 years of age. The bony defect ends were shortened step by step with the sulcated half-ring external fixator. Changes of the blood flow of the distant extremity were measured with pulse-dopplar monitor, reference blood flow, and angiograph. RESULTS: The blood flow of the distant extremity was not affected when bony defect was less than 15% of the original length. Blood circulation disorder would appear in the distant extremity when bony defect ranged from 15% to 20% of the original length. The distant extremity would necrose because of obstruction of blood circulation when bony defect was more than 20% of the original length. CONCLUSIONS: EECL can be recommended if bony defect is less than 15% of the original length. SBTL might be the only feasible way if bony defect is more than 20% of the original length. If bony defect is within 15% and 20%, EECL should be applied with great care while watching the extremity circulation with pulse-Dopplar monitor.

Animals↗
PubMed2000

[Changes of blood vessels in glucocorticoid-induced avascular necrosis of femoral head in rabbits].

OBJECTIVE: To evaluate the effects of fatty tamponade in medullary cavity (serious intramedullary fatty infiltration) on the changes of blood vessels in femoral heads during the pathological process of glucocorticoid (GC)-induced avascular necrosis (AVM) of the femoral heads. METHODS: The animal model of AVN was established with injection of dexamethasone (DEX) at a high dose of 2.5 mg x kg(-1) x d(-1) in rabbits. Histopathological and morphological changes of blood vessels in the femoral heads were investigated during GC-treatment and after the cessation scanning electron microscope, light microscope, and image analysis. RESULTS: At the 2nd week of DEX-treatment, the fatty tamponade in the medullary cavity appeared in the femoral heads. Intramedullary vascular sinusoids were pressed by an excess of lipocytes and became narrow. The impressions of lipocytes on the surface of vascular sinusoids were definitely displayed on the vascular casts and ink-perfused slides of the femoral heads. These changes were pronounced with the prolongation of the treatment and the vascular sinusoids gradually lost their characteristics. Image analysis showed that the vascular area in the femoral heads continuously decreased. At the 8th week, the effects of fatty tamponade were the most marked. Intramedullary vessels became very sparse and the vascular area decreased to 1/4 of the controls. At the 6th week after the GC-treatment cessation, intramedullary fatty infiltration still existed. The blood vessels were fine and sparse, and the structural features of vascular sinusoids disappeared in the load-bearing regions of the femoral heads. At the 4th week, typical osteonecrosis focuses appeared in the femoral heads. The focuses became larger and the degree of osteonecrosis was increasing with the time of experiment. CONCLUSION: The fatty tamponade in the medullary cavity is one of the important pathological factors causing ischemic damage to the femoral heads, and plays an important role in the early stage of GC-induced AVN.

Animals↗
PubMed2000

[The mechanism of biological adaptability of peripheral nerves during limb lengthening in rabbits].

OBJECTIVE: To study the mechanism of subclinical damage and repairing process of peripheral nerves during gradual tibial lengthening. METHODS: Histological investigation, electrophysiological examination of tibial nerve and GAP-43 mRNA expression of sciatic nerve related spinal cord and ganglion were observed in 10%, 20%, 30%, 40% lengthening, and at 2, 4, 8 weeks phases after 40% limb lengthening in 80 rabbits. RESULTS: With the increase of elongation, severer and more obvious nerve damage and stronger expression of GAP-43 mRNA happened. However, nerve regeneration occurred synchronously and the changes recovered gradually within 8 weeks. CONCLUSION: Damage of the peripheral nerves is common during limb lengthening. But, it is temporary and recoverable in case the lengthening rate is < 1 mm/d.

Animals↗
PubMed2000

[Cervical spine operation using coralline hydroxyapatite].

OBJECTIVE: To study the result of using coralline hydroxyapatite (CHA) in cervical anterior fusion and posterior laminoplasty operation. METHODS: 45 patients of cervical operation using CHA were followed up. Of these patients, 27 received anterior fusion and titanium plate fixation (34 levels fused). 18 with spinal stenosis at least at 3 levels, (posterior spinal process-splitting laminoplasty) had 79 split spinal processes fused by CHA. The average follow-up time was 25.9 months. RESULTS: The union rate of CHA was 85.3% in average by anterior approach. The height and angle of the fused level and the anterior salient were well maintained. The JOA score improvement rate was 58.7%. The CHA grafts were kept well between the split spinous processes with a union rate of 70.9%. After operation, the spinal cord moved dorsally, and the flat rate was improved from 0.19 to 0.41. No apparent posterior salient occurred. The JOA score improvement rate was 51%. CONCLUSION: The effect of CHA in cervical antero posterior operation is similar to that of autograft bone, and it is unnecessary to resect a piece of bone from a health region of the body.

Adult↗
PubMed2000

[Morphological changes of mitochondria in apoptosis of esophageal carcinoma cells induced by As(2)O(3)].

OBJECTIVE: In order to make clear how As(2)O(3) targets the cells of esophageal carcinoma, the morphology of mitochondria and expression of bcl-2/bax were selected to study the SHEEC1 cell line during early apoptosis. METHODS: The esophageal carcinoma cell line SHEEC1 was treated by As(2)O(3) with concentrations of 1, 2 and 3 micromol/L for the periods of 2, 4, 6, 12 and 24 h. Annexin-V-Fluorescein and DNA histogram were used to detect the early apoptotic cells by flow cytometry. The morphologic changes of the apoptotic cells were examined by means of light and electron microscopy. Changes in mitochondria of living cells were detected with Rhodamin 123 fluorescent probe by fluorescent microscopy. The expression of bcl-2 and bax in floating cells were determined by immunohistochemical procedures. RESULTS: Typical apoptotic morphological changes were found in SHEEC1 at 24 h after As(2)O(3) treatment. Cells in the early stage of apoptosis were detected by Annexin-V labeled at 4 h. The ultrastructural alterations of mitochondria were found as following: within 4 h after administrating As(2)O(3), mitochondrial hyperplasia with small electron-dense materials in its matrix was the earliest manifestation of cell injury. At 6 h progressive mitochondrial swelling lead to balloon-like appearance and its outer membrane disrupted at 12 h. In all groups, down regulated expression of bcl-2 and over expression of bax were always found in damaged cells. CONCLUSION: In the SHEEC1 cell line morphological changes of mitochondria are the early events in apoptosis induced by As(2)O(3) and apoptosis is closely related to over expression of bax and down-regulating expression of bcl-2. It is possible that As(2)O(3) is a mitochondriotoxic anticancer agent for esophageal carcinoma.

Antineoplastic Agents↗