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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 379 records · Page 21Linked to original sources

Metabolic changes in rats with photochemically induced cerebral infarction and the effects of batroxobin: a study by magnetic resonance imaging, 1H- and 31P-magnetic resonance spectroscopy.

Metabolic changes in rats with photochemically induced cerebral infarction and the effects of batroxobin were investigated 1, 3, 5 and 7 days after infarction by means of magnetic resonance imaging (MRI), 1H- and 31P-magnetic resonance spectroscopy (MRS). A region of T2 hyperintensity was observed in left temporal neocortex in infarction group and batroxobin group 1, 3, 5 and 7 days after infarction. The volume of the region gradually decreased from 1 day to 7 days after infarction. The ratio of NAA/Cho + Cr in the region of T2 hyperintensity in the infarction group was significantly lower than that in the corresponding region in the sham-operated group 3, 5 and 7 days after infarction respectively (P < 0.05). Lac appeared in the region of T2 hyperintensity in the infarction group 1, 3, 5 and 7 days after infarction, but it was not observed in the corresponding region in sham-operated group at all time points. Compared with the sham-operated group, the ratios of beta ATP/PME + PDE and PCr/PME + PDE of the whole brain in the infarction group were significantly lower 1, 3 and 5 days after infarction respectively (P < 0.05), and the ratio of beta ATP/PCr also was significantly lower 1 day after infarction (P < 0.05). Batroxobin significantly decreased the volume of the region of T2 hyperintensity 1 and 3 days after infarction (P < 0.05), significantly increased the ratio of NAA/Cho + Cr in the region 5 and 7 days after infarction (P < 0.05), significantly decreased the ratios of Lac/Cho + Cr and Lac/NAA in the region 5 and 7 days after infarction (P < 0.05), and significantly increased the ratios of beta ATP/PME + PDE and beta ATP/PCr in the whole brain 1 day after infarction (P < 0.05). The results indicated that the infracted region had severe edema, increased Lac and apparent neuronal dysfunction and death, and energy metabolism of the whole brain decreased after focal infarction, and that batroxobin effectively ameliorated the above-mentioned abnormal changes.

Animals↗

[Reduction of FHIT gene expression in primary lung cancer: relationship with the proliferation and apoptosis of tumor cell].

OBJECTIVE: To investigate the role of FHIT(fragile histidine triad) gene in oncogenesis and progression of human lung cancer and explore the relationship of FHIT gene expression with the proliferation and apoptosis of tumor cells. METHODS: The expression of FHIT gene and that of Ki-67 were detected in 166 lung cancer samples and 37 lung benign lesion tissues as control by immunohistochemistry, and the apoptotic level of tumor cell was detected by terminal deoxynucl neotidyl transferase mediated dUTP nick end labelling(TUNEL). RESULTS: (1)The expression level of FHIT gene was found to be significantly lower in lung cancer tissues than in benign lesion tissues (P<0.01); (2)The expression level of FHIT gene was closely related to histological classification, cancer cell differentiation, P-TNM stages and lymph node involvement in lung cancer patients (P<0.05); (3)Lasting and heavy smoking might be one of the important reasons of reduction of FHIT gene expression in lung cancer patients; (4)The postoperative survival time of patients in high FHIT expression group was significantly longer than those in low expression group (P<0.05); (5)The reduction of FHIT gene expression might be related with the over-proliferation and suppression of apoptosis of lung cancer cell(P<0.01). CONCLUSION: FHIT gene may play a role in the regulation of proliferation and apoptosis of lung cancer cell. And reduction of FHIT gene expression may be related to the pathogenesis and development of lung cancer.

Acid Anhydride Hydrolases↗

[Study of a familial insertional translocation involving chromosomes 1 and 7 by using fluorescence in situ hybridization].

OBJECTIVE: To determine the karyotype of a case with a history of spontaneous abortion and terminal deletion by using of conventional G-banding method and search the cause of insertional translocation of chromosomal terminal region. METHODS: Fluorescence in situ hybridization (FISH) technique was performed to analyze the case by using whole chromosome 7 painting probe and subterminal probe of 7q36-->qter which was generated by chromosome microdissection technique. RESULTS: The case was a carrier with a very rare insertional translocation involving chromosomes 1 and 7. The region of chromosome 7q36-->qter was not inserted into chromosome 1. The abnormal chromosome was inherited from her mother. CONCLUSION: The present authors provided an experiment evidence that in this case the chromosome insertional translocation including the terminal region was still a three breakage rearrangement and the terminal deletion found by cytogenetics should be an interstitial deletion. Combining with chromosome microdissection, FISH technique is a powerful diagnostic method for detecting the chromosome structural abnormality.

Adult↗

Conditioned brain-stimulation reward attenuates the acoustic startle reflex in rats.

The acoustic startle reflex (ASR) in rats is attenuated by a light paired with food or, in humans, by "pleasant" pictures. Rats were trained to barpress for lateral hypothalamus (LH) stimulation. ASR amplitudes were then measured at 4 intensities, with or without a light. Control rats that did not receive brain-stimulation reward (BSR) showed initially lower ASR amplitudes than did rats exposed to BSR, but both groups responded similarly with or without light. Next, experimental rats were given BSR in the presence of light but not in its absence. After conditioning, ASR amplitudes were reduced, and ASR thresholds were raised by a mean of 2.6 dB in the light but remained at preconditioning levels without light. No such change was found for control rats or rats with placements outside the LH.

Acoustic Stimulation↗

Effects of low and hyper Dk rigid gas permeable contact lenses on Bcl-2 expression and apoptosis in the rabbit corneal epithelium.

PURPOSE: To study Bcl-2 expression and apoptotic cell shedding of the rabbit corneal epithelium during extended wear of low and hyper Dk rigid gas permeable (RGP) contact lenses. METHODS: Rabbits were fit with either a low or a hyper Dk RGP lens (Dk/Ltotal= 10 and 97). The rabbits wore the lenses for either 24 hours, 3 days, or 1 week at which point they were humanely sacrificed. Immunocytochemistry and western blot analyses were performed to detect Bcl-2 in the corneal epithelium; TUNEL assay (TdT-mediated dUTP nick-end labeling) was used to identify apoptotic epithelial cells. RESULTS: 1) Immunocytochemistry: In the normal cornea, antibodies to Bcl-2 uniformly stained nuclei of all epithelial cell layers. Occasional surface epithelial cells, however, showed no anti-Bcl-2 nuclear staining; concomitant TUNEL assay revealed that all TUNEL-labeled-surface cells were Bcl-2 negative. By contrast, RGP contact lens wear, regardless of test lens oxygen transmissibility or lens wearing interval, significantly decreased both the total number of Bcl-2 negative and TUNEL-labeled cells on the epithelial surface (P < 0.05). In addition, contact lens wear was associated with labeling of keratocytes with TUNEL assay in the anterior stroma. 2) Western blot analysis: Total epithelial layer Bcl-2 expression was markedly decreased in the low Dk lens test group but was similar to control values in the hyper Dk lens test group. CONCLUSION: Bcl-2 protein seems to play an important role in the regulation of apoptotic cell shedding in the normal rabbit corneal epithelium. The identical staining pattern was seen in previous studies of the normal human cornea. RGP contact lens wear, however, appears to block the changes in Bcl-2 protein prior to apoptotic surface cell shedding, suggesting a lens-related anti-apoptotic effect. Taken together, these findings may explain why contact lens wear reduces surface cell exfoliation as previously reported in human studies.

Animals↗

Effect of Cr(VI) exposure on sperm quality: human and animal studies.

The semen status of male workers occupationally exposed to hexavalent chromium(VI) was investigated. Sperm counts from exposed workers were 47.05+/-2.13 x 10(6)/ml and those from control group 88.96+/-3.40 x 10(6)/ml. Sperm motility decreased from 81.92+/-0.41% for the control group to 69.71+/-0.93% for the exposed workers. The levels of zinc, lactate dehydrogenase (LDH), and lactate dehydrogenase C4 isoenzyme (LDH-x) in seminal plasma for the exposed workers were 1.48+/-0.07 micromol/ml, 1.05+/-0.02 x 10(3) U, and 0.47+/-0.01 x 10(3) U, respectively, which were significantly lower than those of 5.72+/-0.15 micromol/ml, 1.49+/-0.02 x 10(3) U, and 0.78+/-0.15 x 10(3) U for the control group, respectively. Follicle stimulating hormone (FSH) (7.34+/-0.34 x 10(-3) IU/ml) in serum from the exposed workers was significantly higher than that (2.41+/-0.08 x 10(-3) IU/ml) from the control group. On the other hand, there were no significant differences in semen volume, semen liquefaction time, luteinizing hormone (LH) level in serum, and Cr concentration in both serum and seminal plasma between the exposed workers and the control group. Feeding Cr(VI) to rats significantly reduced the epididymal sperm counts from 87.40+/-3.85 x 10(6)/g epididymis in control group to 21.40+/-1.20 x 10(6)/g epididymis at a CrO(3) dose of 10 mg/kg body weight and to 17.48+/-1.04 x 10(6)/g epididymis at a CrO(3) dose of 20 mg/kg body weight. Exposure of rats to Cr(VI) also significantly increased the sperm abnormality from 2.75+/-0.06% in the control group to 6.68+/-0.32% in the exposed group at a CrO(3) dose of 10 mg/kg body and to 7.6+/-0.15% at a CrO(3) dose of 20 mg/kg body weight. In exposed rats, there was visible disruption in germ cell arrangement near the walls of the seminiferous tubules. The diameters of seminiferous tubules in exposed rats were smaller. These results suggest that occupational exposure to chromium(VI) leads to alteration of semen status and may affect the reproductive success of exposed workers.

Animals↗

[The study of PAI-1 promotor region gene polymorphism in cerebrovascular disease].

OBJECTIVE: To investigate the relationship between the plasminogen activator inhibitor-1(PAI-1) gene polymorphism and cerebrovascular disease and detect whether it plays an important role in the pathogenesis of cerebrovascular disease. METHODS: Peripheral blood leukocytes samples were collected from 60 normal controls, 65 patients with acute cerebral infarction (CI) and 31 hypertensives complicated with cerebral hemorrhage. The 4G/5G allele polymorphism in the PAI-1 gene promotor region of the leukocytes was genotyped by polymerase chain reaction. The plasma PAI-1 activity was assayed by ELISA. RESULTS: The plasma PAI-1 activity level in the CI group was significantly higher than those in the other two groups. PAI-1 level in 4G allele homozygous genotype was significantly higher than the PAI-1 levels in 4G/5G heterozygous and 5G homozygous. Although PAI-1 level was higher in 4G/5G heterozygous genotype than in 5G homozygous, the difference was not statistically significant. There were significant differences between acute cerebral infarction PAI-1 gene polymorphism and controls (P<0.05), and the frequencies of 4G/4G genotype in patients with acute cerebral infarction (43.08%) were higher than those in normal controls (20.00%, P<0.05). There were no significant differences between hypertensives complicated with hemorrhage (25.81%) and controls (P>0.05), and the PAI-1 levels of the 4G/4G genotype in the female patients with CI were higher than those in the male patients with CI of the same genotype. CONCLUSION: The results suggest that PAI-1 gene polymorphism may be a susceptible factor to acute cerebral infarction in Chinese, and 4G allele homozygous genotype may be the major risk factor for acute cerebral infarction, and it may be especially an independent risk factor of cerebral infarction in female patients.

Cerebral Hemorrhage↗

[Pulsatile rotary pumps with low hemolysis].

As is well known, a pulsatile flow is important in assisted-circulation but it is difficult to produce a pulsatile flow with rotary pump, because excessive hemolysis will be generated. The authors have found that the turbulent shear is the main factor for red cell damage and therefore the key point of pulsatile rotary pumps is to reduce the turbulence by producing a pulsatile flow. In the authors' pulsatile axial pump, the pulsatile flow is obtained by axial reciprocation of constant rotating impeller; the rotation and reciprocation of the impeller are driven separately by a DC motor and a pneumatic device. Though a physiological pulsatile flow could be achieved and turbulence would not increase remarkably because the impeller rotates constantly, a second driver except a DC motor is nevertheless necessary, thus the system will become complicated. In the authors' pulsatile radial pump, a pulsatile flow is achieved by changing the rotating speed of the impeller periodically. Turbulence is minimized by a special design of twisted vanes which enable the blood flow to change its direction rather than its dimension during periodic change of rotating speed. Hemolysis tests demonstrated that the index of hemolysis(IH) of the author's pulsatile radial pump is 0.020, with is slightly more than that of the author's nonpulsatile radial pump(IH = 0.015). Animal experiments indicated that the pulsatile radial pump can assist the circulation of calves for several months without harm to blood elements and organ functions of the recipients.

Animals↗

[Effect of two extracted fraction from Lycopus lucidus on coagulation function].

OBJECTIVE: To find and define the effective fraction of Lycopus lucidus on coagulation. METHODS: Method of comparing turbidity, method of cutting a part of the mice tail and method of breaking glass tube. RESULTS: The two extracted fraction from lycopus lucidus F04-0A and F04-B could inhibit rats platlet aggregation in vitro and mice platelet aggregation in vivo. They could also prolong mice blood coagulation time. However, they had no effect on bleeding time. CONCLUSION: Both F04-A and F04-B had effects on inhibiting platelet aggregation and blood coagulation. Moreover, the activity of F04-A was probably stronger than that of F04-B. F04-A may be the effective fraction from Lycopus lucidus on promoting blood circulation and removing blood stasis.

Animals↗

Proliferation rate of rabbit corneal epithelium during overnight rigid contact lens wear.

PURPOSE: To examine cell proliferation of the normal corneal epithelium and during extended rigid gas-permeable (RGP) lens wear. METHODS: Twenty-three New Zealand White rabbits were fitted unilaterally with either a low oxygen transmissible (Dk/t) or hyper-Dk/t RGP lens, with the other eye serving as a control. The rabbits were injected with 5-bromo-2-deoxyuridine (BrdU) 24-hours later and killed at three time points: 1, 3, and 7 days after injection. Corneas were processed for immunocytochemistry, and sequential digital images were taken from the superior limbus to the central epithelium with an epifluorescence microscope. The total number of BrdU-labeled cell pairs was quantified. RESULTS: The limbus in normal corneas was significantly less populated with BrdU-labeled cells than the central and peripheral epithelium (P < 0.05). The peripheral epithelium adjacent to the limbus was marked by a peak of labeled cells (P < 0.05). Both types of RGP lenses produced an increase in BrdU labeling in the limbus and a dramatic decrease in the central epithelium (80% for low Dk/t, 37% for hyper Dk/t). At day 3 and 7 after BrdU injection, the low-Dk/t lens continued to show decreased BrdU labeling centrally, whereas the limbus remained increased. Hyper-Dk/t lens wear however, showed persistent limbal elevation but equivalent numbers of BrdU-labeled cells centrally at days 3 and 7, compared with control corneas. Keratocytes unexpectedly showed BrdU labeling during RGP lens wear. CONCLUSIONS: Limbus, peripheral, and central epithelium were characterized by different proliferation rates in the normal rabbit cornea. RGP lens wear significantly altered the homeostatic proliferation pattern of the epithelium with the low-Dk/t lens having the most dramatic effect. RGP contact lens wear appears to stimulate proliferation of keratocytes.

Animals↗

Moesin: a potential LPS receptor on human monocytes.

Bacterial endotoxin (lipopolysaccharide, LPS), a glycolipid found in the outer membrane of Gram-negative bacteria, induces the secretion of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha ), interleukin (IL)-1, and IL-6 by monocytes/macrophages. The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock. There is substantial evidence that chronic exposure to LPS in periodontal diseases mediates, at least in part, the tissue destruction associated with the Gram-negative infection. LPS receptor has been shown to be CD14, a 55 kDa protein. LPS-CD14 interactions mediate many monocyte/macrophage functions in the inflammatory response. However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals. More recently, significant work has implicated Toll proteins in LPS-mediated signaling. The purpose of the present work was to investigate, identify, and characterize secondary LPS binding cell surface domain(s) on monocytes/macrophages. Initial experiments with anti-CD14 blocking antibody revealed only partial blocking of the LPS induced TNF-alpha response. The kinetics of these experiments suggested a second, low-affinity receptor. Cross-linking experiments were performed to identify LPS binding sites. Two domains were identified: a 55 kDa protein which was inhibited by anti-CD14 (presumably the CD14 receptor) and a second 78 kDa domain. Partial protein sequencing of the 78 kDa domain using mass spectroscopic analysis ascribed this domain to Moesin (membrane organizing extension spike protein). Preliminary experiments using anti-Moesin monoclonal antibody revealed a dose-dependent blocking of LPS induced TNF-alpha response with a total blocking at 50 microg/ml. Irrelevant isotype controls had no effect. Additional experiments were performed to evaluate the specificity of the anti-Moesin blocking. Separate experiments evaluated anti-Moesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-alpha secretion in response to Staphylococcus aureus stimulation. Anti-Moesin antibody only blocked LPS-mediated events. Histological analysis of tissue sections harvested from LPS-induced skin lesions exhibited a 3-fold reduction of the polymorphonuclear neutrophil infiltrate in Moesin-deficient mice compared to wild type mice. The data suggest that Moesin functions as an independent LPS receptor on human monocytes.

Animals↗

[Coding region cDNA sequence cloning of rat neuroglobin gene, its polymorphism feature and tissue expression profile analysis].

The coding region cDNA sequence of rat neuroglobin (NGB) was obtained by RT-PCR technique using a degeneracy PCR primer pair based on previously reported cDNA sequence of human and mouse NGB gene. Result demonstrated that the coding region cDNA sequence of rat NGB gene is 456 bp in length, which could encode a protein of 151 amino acids. The rat NGB gene is highly homology with mouse (96%) and human (88%) NGB gene. However, several polymorphism sites were also detected in the rat NGB coding region: 113 t/c [L38P], 133 a/g [N45D], 388 a/g[R130G], 417 t/c. The cDNA sequence of rat NGB gene has been registered in GenBank under the accession number AF333245. Moreover, highly expression level of rat NGB in brain, liver, kidney, heart and skeletal muscle was detected by using multiple tissue RT-PCR technique, indicating the functional importance of this novel gene.

Amino Acid Sequence↗

Epitope variability of Bcl-2 immunolocalization in the human corneal epithelium.

PURPOSE: To further study the immunological localization of Bcl-2 protein in human corneal epithelium. METHODS: Three anti-human Bcl-2 antibodies, generated against amino acid residues (aa) 4-21 (polyclonal), 1-205 (monoclonal), and 41-54 (monoclonal), were used to localize Bcl-2 protein immunocytochemically in fresh eye bank donor human corneas. RESULTS: In the central corneal epithelium, two anti-Bcl-2 antibodies (aa 4-21 and aa 1-205) showed intense cytoplasmic staining of basal epithelial cells. These antibodies produced similar staining in the limbal epithelium, with gradually less intense staining of wing and superficial cells. By contrast, as previously reported, a monoclonal antibody to aa 41-54 stained nuclei of all epithelial cell layers with the exception of some surface corneal epithelial cells; this antibody also demonstrated very bright anti-Bcl-2 staining of Langerhans cells localized in the peripheral corneal epithelium. CONCLUSION: In our previous study, Bcl-2 protein was immunocytochemically localized to the nuclear compartment of all corneal epithelial cell layers with the use of antibodies specific for the regulatory flexible loop domain of Bcl-2. However, Bcl-2 can also be uniquely localized to the cytoplasm of the corneal epithelium with the use of antibodies generated against aa 4-21 and aa 1-205. Taken together, these results using epitope specific antibodies indicate that different epitopes on the Bcl-2 protein are available for antibody binding within different cells and cellular compartments, suggesting that proliferation and differentiation may lead to changes in the Bcl-2 structure and conformation within different compartments of the epithelial cells themselves.

Aged↗

A retrospective study of continuous renal replacement therapy versus intermittent hemodialysis in severe acute renal failure.

OBJECTIVE: To investigate the efficacy of continuous renal replacement therapy (CRRT) versus intermittent hemodialysis (IHD) in patients with severe acute renal failure (ARF). METHODS: One hundred and ninety-three severe ARF patients who received renal support between December 1978 and December 1998 were involved in this study. Of them, 101 (52.3%) were treated with CRRT (CRRT group), and 92 (47.7%) with IHD (IHD group). RESULTS: Sixty (59.4%) patients in the CRRT group got through the acute phase of disease and 41 (40.6%) patients did not survive while in the IHD group 59 (64.1%) patients survived and 33 (35.9%) patients did not. No significant difference in survival rate was found between the two groups. 24 of 64 patients (37.5%) in the CRRT group with multiple organ dysfunction syndrome (MODS) survived, while in the IHD group, 8 out of 44 (27.3%) survived, their survival rate was much lower than that in the CRRT group. Patients in CRRT group were more severely ill, as manifested by lower mean arterial pressure, higher APACHE II score, more dysfunctioned organs and requiring mechanical ventilation and vasopressor support as compared with patients in the IHD group, CRRT was found to improve hemodynamic stability with a better fluid balance and control of biochemical status, increased nutritional intake and a shorter duration of acute renal failure (P < 0.05). CONCLUSION: CRRT perhaps may be the best choice in the treatment of severe ARF patients, for it can offer several distinct advantages compared to IHD. These may contribute to improving the survival rate of ARF patients, particularly those that are critically ill patients.

Acute Kidney Injury↗

Effect of copper aspirinate on contraction of isolated rabbit aortic strips.

AIM: To investigate the effect of copper aspirinate on contraction of vascular smooth muscle. METHODS: Isolated rabbit aortic strips, including intact endothelium strips and endothelial cell-denuded aortic strips, were suspended in modified Krebs'solution to determine effects of copper aspirinate on the contraction induced by norepinephrine (NE), KCl, and CaCl2, while CuSO4, aspirin, and vehicle were used as controls. RESULTS: Copper aspirinate possessed antagonistic effect on contraction of rabbit aortic strips induced by NE with an IC50 value of 31 nmol/L, while CuSO4 had much l ess antagonistic effect with an IC50 value of 0.29 micromol/L, and aspirin did not work in the same preparation. No effect of copper aspirinate were found on the contraction induced by KCl and CaCl2. Effects on endothelial cell denuded aortic strips were similar to those in the normal aortic strips. CONCLUSION: Copper aspirinate possessed different effects from aspirin and CuSO4 on vascular smooth muscles. It inhibited contraction induced by NE with an activity stronger than CuSO4 at the same Cu2+ concentration, this action might be due to blockade of the receptor-operated Ca2+ channels, and it might not be linked to the endothelium.

Animals↗

Increment of calcium-activated and delayed rectifier potassium current by hyposmotic swelling in gastric antral circular myocytes of guinea pig.

AIM: To observe the effect of hyposmotic swelling on calcium-activated potassium current [IKCa] and delayed rectifier potassium current [IKV] in gastric antral circular myocytes of guinea pig. METHODS: The whole cell patch-clamp technique was used, and the myocytes were isolated by collagenase. Cells were swelled by the hyposmotic solution (200 Osmmol/kg). RESULTS: The hyposmotic solution markedly increased IKCa and IKV. The increase of IKCa was markedly inhibited by tetrathylammonium (TEA) 4 mmol/L and charybdotoxin (ChTX) 200 nmol/L. The increase of IKV was incompletely blocked by TEA and completely blocked by 4-aminopyridine (4-AP) 10 mmol/L. There was no significant difference between the amplitudes of the increase of IKCa and IKV (P < 0.05). IKCa increased (17.0 +/- 4.8) s after the cells were perfused with the hyposmotic solution, whereas IKV increased (30.7 +/- 13.7) s after the cells exposed to the hyposmotic solution. There was significant difference between the latency of IKCa and IKV (P < 0.05). CONCLUSION: Hyposmotic swelling increased both IKCa and IKV, and the increment was likely related to the cell volume regulation.

4-Aminopyridine↗