Biomedical subjects

H Li

Publications and source records attributed to H Li.

At least 667 records · Page 37Linked to original sources

PubMed2000

Expression of hyaluronan receptors CD44 and RHAMM in stomach cancers: relevance with tumor progression.

Interactions of hyaluronic acid (HA) with its binding proteins CD44 and RHAMM (receptor for HA-mediating motility) have been proposed to be important in promoting tumor progression and dissemination. However, a comparative study of their expression patterns in stomach cancer and its associated lesions is not yet available. To address this issue, the combined examinations of pathology, immunocytochemistry and Western blot hybridization were performed on advanced gastric cancer specimens as well as their preneoplastic and non-cancerous counterparts. Alternative CD44 expression was observed in the gastric mucosa with different lesions. CD44 proteins harboring variant exon 6 (CD44 v6) was detected only in cancer tissues with a total positive rate of 14% (10/74). Intracellular RHAMM molecules in Mr 93000 to 95000 were expressed in 3/31 non-cancerous mucosa. RHAMM detection rates increased along with tumor progression. Irrespective of the differences of gross and morphological pattern, majority (54/74) of cancer cases expressed multiple RHAMM isoforms in Mr 40000-45000, 64000, 70000-73000, 85000 and 93000-95000 with the appearance of cell surface immunocytochemical labeling. Among CD44 variant isoforms, v6 is more relevant with malignant transformation of gastric epithelium. Expression of RHAMM, especially the cell surface variants, is closely correlated with tumor progression (P<0.01). Expression of CD44 and RHAMM may benefit the invasion and metastasis of gastric cancer cells presumably in a reciprocal manner.

Blotting, Western↗

PubMed2000

Clinical observation on treatment of non-parvicellular carcinoma of the lung with jin fu kang oral liquid.

Jin Fu Kang Oral Liquid ([symbol: see text]), made of traditional Chinese drugs for supplementing qi and nourishing yin, was developed according to the common symptoms in lung carcinoma with deficiency of both qi and yin. Of the 96 cases in the Jin Fu Kang group, 1 case got complete remission (CR) after treatment, 8 cases partial remission (PR), 52 cases no change (NC), PR + NC covering 63.5%. Of the 52 cases in the group of Jin Fu Kang plus chemotherapy, 11 cases got PR after treatment, 26 cases NC, PR + NC covering 71.2%. Of the 25 cases in the chemotherapy group, 4 cases got PR after treatment, 11 cases NC, PR + NC covering 60.0%. The results show that the therapeutic effectiveness in the Jin Fu Kang group and the group of Jin Fu Kang plus chemotherapy was better than that in the chemotherapy group. The one-year survival rate and the two-year survival rate after treatment in the Jin Fu Kang group were 67.3% and 67.3% respectively; 66.7% and 66.7% in the group of Jin Fu Kang plus chemotherapy; and 40.3% and 0.0% in the chemotherapy group. The improvement of clinical symptoms, increase of body weight and improvement of health situation (KPS marks) after treatment in both the Jin Fu Kang group and the group of Jin Fu Kang plus chemotherapy were better than that in the chemotherapy group. Some indicators of immunology and hemogram after treatment were greatly improved in the Jin Fu Kang group, worse in the chemotherapy group, but no obvious improvement in the group of Jin Fu Kang plus chemotherapy.

Adenocarcinoma↗

PubMed2000

A pyrroline derivative of mexiletine offers marked protection against ischemia/reperfusion-induced myocardial contractile dysfunction.

The efficacy and mechanism of protection of a new 2,2,5, 5-tetramethylpyrroline derivative of mexiletine, MEX-NH, against ischemia/reperfusion-induced cardiac dysfunction are reported. The MEX-NH and its nitroxide metabolite are membrane-permeable antioxidants. Studies were performed in an isolated rat heart model to measure the efficacy of MEX-NH in preventing postischemic injury. Serial measurements of contractile function and coronary flow were performed on hearts subjected to 30 min of global 37 degrees C ischemia followed by 45 min of reperfusion. Hearts were either untreated or treated with 25 microM MEX-NH or MEX for 1 min before ischemia. The hearts treated with MEX-NH showed marked recovery of left ventricular developed pressure (96.3 +/- 2.7% of preischemic value) compared with untreated (13.7 +/- 1.0%) or MEX-treated (19.9 +/- 2.7%) hearts. The cardiac sarcolemmal Na(+),K(+)-ATPase activity showed that the enzyme activity was fully restored in hearts treated with MEX-NH compared with 65 +/- 5.3% inhibition in the untreated hearts. Competitive inhibition of [(3)H]ouabain binding revealed that the MEX-NH binds at the K(+)-binding site of the enzyme. The present study establishes that the compound MEX-NH provides marked protection against ischemia/reperfusion-induced contractile dysfunction in isolated hearts. A combination of reversible inhibition of Na(+)/K(+)-ATPase activity during ischemia and site-targeted antioxidative effect upon reperfusion seems to contribute to this cardioprotection.

Animals↗

PubMed2000

Cyclic GMP mediates apoptosis induced by sulindac derivatives via activation of c-Jun NH2-terminal kinase 1.

Sulindac sulfone (Exisulind) induces apoptosis and exhibits cancer chemopreventive activity, but in contrast to sulindac, it does not inhibit cyclooxygenases 1 or 2. We found that sulindac sulfone and two potent derivatives, CP248 and CP461, inhibited the cyclic GMP (cGMP) phosphodiesterases (PDE) 2 and 5 in human colon cells, and these compounds caused rapid and sustained activation of the c-Jun NH2-terminal kinase 1 (JNK1). Rapid activation of stress-activated protein/ERK kinase 1 (SEK1) and mitogen-activated protein kinase kinase kinase (MEKK1), which are upstream of JNK1, was also observed. Other compounds that increase cellular levels of cGMP also activated JNK1, and an inhibitor of protein kinase G (PKG), Rp-8-pCPT-cGMPS, inhibited JNK1 activation by the sulindac sulfone derivatives. Expression of a dominant-negative JNK1 protein inhibited CP248-induced cleavage of poly(ADP-ribose) polymerase, a marker of apoptosis. Thus, it appears that sulindac sulfone and related compounds induce apoptosis, at least in part, through activation of PKG, which then activates the MEKK1-SEK1-JNK1 cascade. These studies also indicate a role for cGMP and PKG in the JNK pathway.

Apoptosis↗

PubMed2000

[A study of transgenic IFV cattle integrated with human serum albumin gene].

The mammary gland expression vector (pcDNA 3.1-GCALBm) containing the full-length sequence of human serum albumin (hALB) cDNA and intron 1 as well as the goat beta-casien gene promoter and 5' up-stream regulatory sequence was constructed. The vector was micro-injected into bovine IVF eggs. The embryos were in vitro cultured to the late stage of morulae, and then few embryo cells were aspirated for the implantation detection of target gene integration and SRY DNA sequence using nested-PCR. Afterwards, ten integrated embryos were selected to transfer into eight recipients and three were pregnant. The pregnant rate was 37.5%(3/8). However, two were miscarried in mid-trimester but one was pregnant at term to deliver a male transgenic cattle integrated with hALB mini-gene. The transgenic efficiency was 12.5% (1/8).

Animals↗

PubMed2000

[Tissue culture induced translocation conferring powdery mildew resistance between wheat and Dasypyrum villosum and its marker-assisted selection].

Glutamate oxaloacetate transaminase (GOT) electrophoretic analyses were performed in 175 regenerants arising from immature embryos of crosses between wheat (Triticum aestivum L.) and 6D/6V substitution stocks. The GOT-V2 coding specific enzyme band was absent in two regenerants, designated 98R149 and 98R159 respectively, originated from cross of Yi 4095 and 6D/6V substitution stock c.v. RW15. Pm21 gene linked SCARs (Sequence Characterized Amplified Regions) analysis indicated that 6VS chromosome arms existed in 98R149 and 98R159. Fluorescence in situ hybridization with total genomic DNA extracted from Dasypyrum villosum (L.) as a probe confirmed the occurrence of translocation between 6V chromosome and a wheat one in the two regenerants mentioned above. 98R149 and 98R159 were immune to powdery mildew (Erysiphe graminisDC. f. sp. tritici) inoculation with mix races collected from Hebei Province. The results of the present paper added another feasible example of useful translocations via tissue culture.

Aspartate Aminotransferases↗

PubMed2000

Basaloid squamous cell carcinoma of the vagina metastasizing to the lung. A case report.

BACKGROUND: While observed on the vulva, basaloid squamous cell carcinoma (BC) of the vagina is extremely rare, with no reported cases. CASE: A 54-year-old, African American woman presented with carcinoma metastatic to both lungs, morphologically similar to her BC of the vagina four years previously. She was treated initially in 1995 with local excision. Reexcision and radiation therapy were given for a recurrence in 1996. CONCLUSION: BC of the vagina is an extremely rare and aggressive tumor, which can recur and metastasize.

Carcinoma, Basosquamous↗

PubMed2000

[Expression of 3'-truncated preS/S gene in transgenic mice].

The 3'-truncated preS/S region from HBV genome, encoding a transcriptional transactivator, was cloned and a recombination expression vector for 3'-truncated HBV preS/S sequences under the control of the CMV promoter was constructed by recombination DNA techniques. Then, the expression vector DNA was microinjected into pronuclei of fertilized mouse oocytes. Founders of transgenic mice harbouring the recombination gene which can be expressed were screened by polymerase chain reaction (PCR) at genomic DNA level and confirmed by ELISA andlysis at protein level. Two of 15 mice in one series of microinjections showed the expression of 3'-truncated preS/S gene from HBV genome. The expression vector of 3'-truncated preS/S gene might be helpful for further studies of relationship between the expression production of 3'-truncated preS/S sequence and HBV-associated oncogenesis in vitro. The transgenic mice with expressing 3'-truncated preS/S gene will provide new insight into its roles in the development of human hepatocelluar carcinoma (HCC) in vivo.

Animals↗

PubMed2000

[Establishment of a method for GUS gene transferring into wheat (Triticum astivum L.) embryos by low energy ion beam implantation].

Physical parameters influencing transformation of wheat mediated by low energy ion beam, including type of ion, parameters of ion energy, dose and dose rate, were studied. Ar+ was regarded as suitable ions implanted in transformation. 20-25 keV of energy, 4.68 x 10(16) ions/cm2 of dose, 2.6 x 10(15) ions/cm2 of dose rate were chosen as appropriate implantation parameters. The suitable culture conditions for induction and growth of callus and the optimal selection scheme were established, After implantation and selection, resistant calli and hygromycin-resistant plantlets were obtained from three varieties. Molecular analysis data proved that GUS gene had integrated into the wheat genome. The mature embryo transformation efficiency of wherat variety Yangmai 5, Yangmai 158, Wanmai 32 reached 9.5%, 10.8%, 11.2% measured in produced hygromycin-resistant callus and 1.4%, 3.4%, 1.7% measured in regenerated plants, respectively, This experiment provides a basis for further investigation of wheat transformation system. Low energy ion beam mediated transformation can be extended to other plant recalcitrant to Agrobacterium tumefaciens as soon as methodological parameters are optimized.

Gene Transfer Techniques↗

PubMed2000

[In vitro dissolution study on the hydroxyapatite biocoatings].

This paper has studied the dissolution behavior of the plasma sprayed and electrochemically prepared hydroxyapatite(HA) biocoatings in the simulated body fluid. XRD and SEM show that the plasma sprayed coating and post-heat treated HA coatings are more soluble, and CaO and alpha-TCP in the coatings gradually disappear and CaCO3 forms during the immersion. The composition of the electrocrystallized and alkaline-treated HA coatings is basically unchanged, and the coatings are more stable in the simulated body fluid.

Coated Materials, Biocompatible↗

PubMed2000

[An approach to achieve classification of QRS waves with wavelet multiresolution analysis and fractal dimension].

This paper discussed the theoretical analysis of multiresolution ECGs decomposition and expounds the calculation of the fractal dimension. Based on Mallat's multiresolution analysis and fractal dimension of the series, a new approach to classify the QRS complex was provided: the QRS complex was decomposed with a quadratic spline wavelet. At scale 4, the fractal dimension of the decomposed series was calculated, the values of modulus maxima of wavelet transform and the fractal dimension were used as discriminatory criteria to classify QRS. The method was simple and had high anti-noise ability.

Algorithms↗

PubMed2000

[Stress-corrosion test of TIG welded CP-Ti].

In this study TIG (Tungsten Inert Gas) welded CP-Ti were subjected to stress-corrosion test under 261 MPa in artificial saliva of 37 degrees C for 3 months. No significant difference was noted on mechanical test (P > 0.05). No color-changed and no micro-crack on the sample's surface yet. These results indicate that TIG welded CP-Ti offers excellent resistance to stress corrosion.

Biocompatible Materials↗

PubMed2000

Morphometric analysis of rat testis following chronic exposure to cigarette smoke.

PURPOSE: To assess the effect of chronic exposure to cigarette smoke on spermatogenesis in Sprague-Dawley rats. MATERIALS AND METHODS: Twenty 5-day-old Sprague-Dawley rats were exposed daily to cigarette smoke by the Walton smoking machine for a period of 15, 30, and 45 days. Age-matched Sprague-Dawley rats exposed to room air with the smoking machine served as controls. Rats were sacrificed from each group at 15, 30, and 45 days and the testes were removed. Fifty seminiferous tubules were assessed in each group. Morphometric and histopathologic analyses of the testes were carried out. The following parameters were studied: (1) Number of germ cells (step 7 spermatids), (2) seminiferous tubule diameter, (3) height of germinal epithelium, (4) presence of degenerating or sloughed cells, (5) failure of release of spermatids into the tubular lumen, and (6) degeneration of Leydig cells. Statistical analysis was performed using ANOVA followed by the t test. RESULTS: There was a significant decrease in the germ cell count (step 7 spermatids) in the rats exposed to cigarette smoke for 30 days (93.19 versus 98.15 step 7 spermatids in the control animals (p < 0.001). This decrease persisted in the rats exposed to cigarette smoke for 45 days (82.47 versus 103.01 step 7 spermatids in control animals, p < 0.001). The mean seminiferous tubule diameter was significantly reduced only in the rats exposed to cigarette smoke for 45 days (0.283 microm versus 0.299 microm in the control animals, p < 0.001). There was no significant difference in the height of the germinal epithelium, and no degenerating cells were noted in either group. CONCLUSIONS: Cigarette smoke adversely affects spermatogenesis in pubertal Sprague-Dawley rats.

Animals↗

PubMed2000

Chronic cigarette smoking induces an oxidantantioxidant imbalance in the testis.

OBJECTIVES: We have previously demonstrated the harmful effect of chronic inhalation of cigarette smoke on the testis in Sprague-Dawley rats. The aim of the present study was to investigate the role of free oxygen radicals and reactive oxygen species in inducing testicular damage in Sprague-Dawley rats following exposure to cigarette smoke. MATERIALS AND METHODS: Sprague-Dawley rats, 25 days old, were exposed daily to cigarette smoke by the Walton smoking machine for a period of 15, 30, and 45 days. Age-matched Sprague-Dawley rats were exposed to room air with the smoking machine and served as controls. Rats were sacrificed from each group at 15, 30, and 45 days and the testes were removed. The testicular tissue levels of glutathione and lipid peroxidation product malonaldehyde (MDA) were measured colorimetrically using the Bioxytech GSH-400 and LPO-586 kits, respectively. The activity of glutathione peroxidase was assessed colorimetrically using the Bioxytech GPx-340 kit. Statistical analysis was performed using ANOVA followed by the t test. RESULTS: There was a 47.8% increase in the MDA in the treated rat testis compared with the control rat after 45 days of exposure to cigarette smoke or air, respectively (p < 0.05). This was associated with a parallel significant decrease in the level of glutathione and glutathione peroxidase activity in the treated rat testis, 38.2% and 29.1%, respectively, after 45 days of cigarette smoke exposure (p < 0.05). No significant difference was noted in the levels of glutathione, glutathione peroxidase, and lipid peroxidation end products after 15 and 30 days of treatment. CONCLUSIONS: Chronic cigarette smoke inhalation is associated with an increase in the level of oxidants and a simultaneous decrease in the level of antioxidants in the rat testis. This abnormality of the oxidant-antioxidant balance may be one of the mechanisms leading to testicular tissue damage and abnormal spermatogenesis in the rat testis following chronic inhalation of cigarette smoke.

Animals↗

PubMed2000

Effects of Veratrum nigrum alkaloids on central catecholaminergic neurons of renal hypertensive rats.

AIM: To study the central hypotensive mechanism of Veratrum nigrum L var ussurience Nakai alkaloids (VnA) in renal hypertensive rats(RHR). METHODS: The quantitative method of immunocytochemistry (ICC) was used to observe and detect the effect of VnA (30 micrograms.kg-1, i.v.) on activity of central catecholaminergic (CA) neurons of C1, C2, A1, and A5 areas in RHR. RESULTS: VnA increased the immunoreactivity (IR) of tyrosine 3-monooxygenase (TM)-immunopositive (IP) neurons of C1, C2, and A5 areas in RHR experimental group compared with RHR control group [positive units: (1.9 +/- 0.4), (1.18 +/- 0.23), (1.2 +/- 0.4) vs (0.15 +/- 0.22), (0.31 +/- 0.16), (0.69 +/- 0.20), respectively]; IR of TM-IP neurons of C1 and C2 areas in RHR control group was decreased compared with sham-operated group [positive units: (0.15 +/- 0.22), (0.31 +/- 0.16) vs (1.45 +/- 0.29), (1.36 +/- 0.25), respectively]. CONCLUSION: VnA increased the activity of central CA neurons in RHR to exert its hypotensive effect.

Animals↗

PubMed2000

Nanoleakage of cervical restorations of four dentin bonding systems.

PURPOSE: The aim of this study was to evaluate the degree of nanoleakage of restorations placed in cervical preparations with dentin bonding systems. MATERIALS AND METHODS: The dentin bonding systems used were Single Bond, One Coat Bond, Prime & Bond NT/NRC, and PermaQuik. Ten saucer-shaped cervical preparations were bonded with one of the dentin bonding systems and restored with Silux Plus resin composite in each group. After 24 hours storage in 37 degrees C water, restorations were finished and the surrounding tooth surfaces were coated with nail varnish. The samples were immersed in 50% w/v solution of silver nitrate for 24 hours, and exposed to photodeveloping solution for 8 hours. The samples were cut longitudinally through the center, polished, carbon coated and observed in a Field Emission SEM using backscattered electron mode. The degree of silver penetration along the preparation wall was observed and calculated as a percentage of the total preparation wall length. Results were analyzed by one-way ANOVA and LSD tests. RESULTS: PermaQuik demonstrated the lowest leakage score and the least silver deposition within the hybrid layer, while Prime & Bond NT/NRC showed the greatest leakage scores and the most silver deposition within the hybrid layer. Different nanoleakage patterns were observed for the different adhesive systems. CONCLUSION: First, the composition of each adhesive system may play a role in the different leakage patterns. Second, the current dentin bonding systems used in this study did not achieve perfect sealing at the restoration-dentin interface. This may influence the durability of the bond to dentin.

Acid Etching, Dental↗

PubMed2000

Anticancer treatment of endostatin gene therapy by targeting tumor neovasculature in C57/BL mice.

Antiangiogenesis strategy has been widely recognized as a viable approach to fight cancer. Considering the high cost and inconvenience of protein therapy of endostatin (ES), which is a potent antiangiogenic protein, we attempted to explore the inhibitory effect of ES gene therapy on tumor growth and metastasis. In this experiment, Lewis lung carcinoma (LLC)-bearing C57/BL mice were used to evaluate the antitumor effect of ES gene therapy and its impairment of tumor neovasculature. The data showed that the ectopic ES in circulation expressed by intramuscular administration of formulated ES-encoding plasmid DNA significantly suppressed primary tumor growth and lung metastasis in LLC-bearing C57/BL mice. Hence, our results demonstrated the inhibitory effect of ES gene therapy on angiogenesis-dependent tumor growth and metastasis.

Angiogenesis Inhibitors↗

PubMed2000

The role of the microlymphatic valve in the propagation of spontaneous rhythmical lymphatic motion in rat.

Male Wistar rats (n = 12) with the mesenteric preparation were used to quantitatively investigate the characteristics of wave-like propagation of spontaneous rhythmical lymphatic motion and to explore the mechanism of microlymphatic valve on the activity of lymphatic motion. The dynamical behaviors of collecting lymphatics were visualized by a closed circuit TV system. The frequency, amplitude, and phase angle of the diameter oscillation, the spreading speed of peristaltic wave and the contractile index (CI) of rhythmical lymphatic motion were measured and calculated by the image processing system. The lymphatic segment between two adjacent valves, named by lymphangion, was a basic unit of microlymphatic activity. The present results revealed that there was a wave-like propelling of the contractile activity progressively from one lymphangion to the next. No significant characteristic differences were observed from the two adjacent lymphangion units except the increasing contractile index. The motion wave propagation from upstream over a valve to down stream led to a significant phase angle change. The pacemaker site of lymphatic motion seemed to be at the inlet side of the valve in each lymphangion unit. The contractile motion wave propagated just within each lymphangion unit. The lymph flow over the valve converted the pressure changes between two adjacent lymphangions and stimulated a new contraction wave at the next inlet site of valve. The endothelium response to wall tension and shear stress alteration near the inlet valve site might be one of the pacemaking mechanisms of lymphatic motion.

Animals↗