Resonance states of open quantum dots.
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Journal Article↗
Biomedical subjects
H Guo
Publications and source records attributed to H Guo.
Dissipative quantum transport in a quantum wire.
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Journal Article↗
The abnormal distribution of mossy fiber bundles and morphological abnormalities in hippocampal formation of dreher(J) (dr(J)/dr(J))mouse.
The organization of pyramidal cells and mossy fibers in the hippocampal formation of homozygous dreher(J) mutant mice was investigated using Timm's and Golgi methods. Five clear abnormalities were found: (1) some pyramidal cells were located below the infrapyramidal mossy fiber layer, (2) mossy fibers emerged in diffuse fashion from between the suprapyramidal and infrapyramidal mossy fiber layers, and their fibers invaded within the pyramidal cell layer, where they traveled as 3-6 small, usually quite short, bundles, (3) some normally situated pyramidal cells had unusual contacts with mossy fibers at two or three places on their apical and/or basal dendrites, (4) some normally situated pyramidal cells had abnormal dendritic trees typified by the occurrence of fine-caliber dendritic branches extending out of the apical dendrite or the apical portion of the soma, and (5) a few Timm positive fibers extending from the dentate hilus to the dentate molecular layer in both dreher(J) and control mice were observed. These abnormalities indicate that in the hippocampal formation a variety of cell populations and neuronal circuits can be indirectly modified by the dreher mutation.
Animals↗
Magnetic ordering in the three-dimensional site-disordered Heisenberg model.
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Journal Article↗
Oxidized lipid-mediated alterations in proteoglycan metabolism in cultured pulmonary endothelial cells.
Compared to cholesterol or linoleic acid (18:2), oxidized lipids such as cholestan-3 beta, 5 alpha, 6 beta-triol (triol) and hydroperoxy linoleic acid (HPODE) markedly impair endothelial barrier function in culture [Hennig and Boissonneault, 1987; Hennig et al. 1986]. Because proteoglycans contribute to vascular permeability properties, the effects of cholesterol and 18:2 and their oxidation products, triol and HPODE, on endothelial proteoglycan metabolism were determined. While cholesterol was without effect, a concentration-dependent decrease in cellular proteoglycans (measured by 35S incorporation) was observed after exposure to triol. Compared to control cultures, cholesterol reduced mRNA levels for the proteoglycans, perlecan and biglycan. Triol had a similar effect on biglycan but not an perlecan mRNA levels. Compared to 18:2, 1,3 and 5 microM HPODE depressed cellular proteoglycans. Perlecan mRNA levels were reduced more by HPODE when compared to 18:2. Biglycan mRNA levels were reduced by 3 microM, but not by 5 microM HPODE. These data demonstrate that oxidized lipids such as triol and HPODE can decrease cellular proteoglycan metabolism in endothelial monolayers and alter mRNA levels of major specific proteoglycans in a concentration-dependent manner. This may have implications in lipid-mediated disruption of endothelial barrier function and atherosclerosis.
Animals↗
Clinical neuroimmunology.
Clinical research has focused on autoimmune disease (AID) for a couple of decades. More sensitive and specific methods have been developed for neuroimmunological research. Gamma fraction bands (bands separated by electrophoresis and visualized by amino black staining) and IgG fraction bands (bands separated by iso-electric focusing and visualized by immunostaining) are used instead of oligoclonal bands. Myasthenia gravis (MG) mainly involves acetylcholine receptors of the postsynaptic membrane at the neuromuscular junction. Myasthenia gravis has been considered to be a generalized AID, because 7% of patients with myasthenia gravis associate with other AIDs and more than one autoimmune antibody is detected in 52.5% patients with myasthenia gravis. Pyramidal signs in myasthenia gravis patients are described; the possible mechanism may at least be partly due to the acetylcholine receptor antibody. P2 protein and its antibody are studied in patients with acute and chronic inflammatory demyelinating polyneuropathy.
Adolescent↗
Cooling-rate dependence of the ground-state energy using microcanonical simulated annealing.
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Journal Article↗
Human keratinocytes express EMMPRIN, an extracellular matrix metalloproteinase inducer.
Increased levels of matrix metalloproteinases are associated with tissue degradation and remodeling during tumor invasion and wound healing. In both processes, there is evidence that cell interactions between fibroblasts and tumor cells or keratinocytes lead to increases in metalloproteinase production. We have previously isolated and purified a tumor cell surface protein, EMMPRIN (extracellular matrix metalloproteinase inducer), which stimulates production of interstitial collagenase, gelatinase A, and stromelysin-1 by fibroblasts, and we have obtained cDNA clones that encode the EMMPRIN protein from LX-1 human lung carcinoma cells. In this study we report immunolocalization of EMMPRIN around the surface of human keratinocytes in vitro and in vivo, and isolation of cDNAs that encode the entire open reading frame for EMMPRIN from a human keratinocyte library. Comparison of the EMMPRIN cDNAs from normal human keratinocytes and LX-1 human tumor cells by nucleotide sequence analysis, expression of the recombinant proteins, and in vitro translation using the cDNAs from the two sources indicate that they express very similar forms of EMMPRIN. Native EMMPRIN isolated directly from extracts of keratinocytes, however, is slightly smaller in size and is present at a lower concentration compared with that from LX-1 tumor cells. These results establish the presence of EMMPRIN in the normal epidermis and raise the possibility of its involvement in regulation of matrix remodeling at the epidermal-dermal interface.
Amino Acid Sequence↗
Effect of cigarette smoking on pentane excretion in alveolar breath.
The concentrations of acetone, isoprene, and pentane in alveolar breath were examined in 50 smokers and 50 nonsmokers by gas chromatography. The baseline pentane in smokers was 0.17 +/- 0.03 nmol/L (mean +/- SE), which was not different from pentane in nonsmokers (0.23 +/- 0.03 nmol/L). There were also no differences between smokers and nonsmokers in the concentrations of acetone and isoprene. Serial breath samples were obtained from 15 smokers before smoking and at 5, 15, and 60 min after smoking. Although acetone was not altered by smoking, isoprene increased by 86% +/- 26% 5 min after smoking (P <0.001) and returned to baseline 10 min later. Pentane increased by 456% +/- 156% 5 min after smoking (P <0.001) and remained increased 10 min later (204% +/- 73% of baseline, P <0.05). Isoprene concentrations in mainstream cigarette smoke were >5000 times greater than breath concentrations, whereas pentane could not be detected in mainstream smoke. Because pentane is produced from the peroxidation of n-6 polyunsaturated fatty acids, the results provide evidence that cigarette smoking causes an immediate increase in lipid peroxidation.
Acetone↗
Hyaluronan distribution in the normal epithelium of esophagus, stomach, and colon and their cancers.
The distribution of hyaluronan (HA) in normal gastrointestinal wall and in tumors originating from their epithelium was studied using a specific probe prepared from cartilage proteoglycan (bHABC, biotinylated hyaluronan binding complex). The normal stratified squamous epithelium of esophagus showed an intense HA staining in the basal and lower intermediate layers, whereas the simple epithelia in the stomach and large intestine were HA negative. Esophageal in situ carcinomas expressed HA also in the cell layers close to the luminal surface, in regions normally negative. Most of the invasive squamous cell carcinomas maintained their HA expression, but in very poorly differentiated types the tumor parenchyma was devoid of HA. In both gastric and colonic adenocarcinomas the tumor parenchyma showed no HA. The stromal tissue was intensely HA positive in all tumors. Cancer cells invading the intestinal smooth muscle were surrounded by copious amounts of HA, whereas the muscular layer was otherwise very poor in HA staining. These results show that relatively well differentiated carcinoma cells themselves retain the high or low HA expression pattern of their original epithelium, whereas tumors stimulate HA deposition in the surrounding stroma.
Colon↗
[Study on combined acupunctural and general anesthesia in pneumonectomy].
Combined acupunctural and general anesthesia in pneumonectomy were studied. The result showed that general anesthesia complemented with electro-acupuncture at He Gu (LI 4) and San Yang Luo(SJ 8) reduced amount of Fentanyl 38-85 micrograms/h compared with general anesthesia alone. There were no statistical difference in blood pressure and heart rate during the operation in every group, all of the SPO2 were in normal range. It was considered that acupuncture in combination with general anesthesia could reduce dosage of anesthetics and the inhibition of physiological function. It is a practical and acceptable anesthetic method by the surgeon and patient.
Acupuncture Analgesia↗
Sympathetic influences on electrical and mechanical alternans in the canine heart.
OBJECTIVE: The aim was to investigate the influence of the sympathetic nervous system on the induction of mechanical and electrical alternans in the intact canine heart. METHODS: Experiments were performed on 8 open-chest dogs anesthetized with sodium pentobarbital. A micromanometer-tipped catheter was used to measure left ventricular pressure, dp/dt and the time constant of isovolumic relaxation. Rapid atrial pacing was used to induce alternans and the left stellate ganglion was stimulated electrically to alter sympathetic tone. The longest pacing cycle length that showed a significant alternation in peak systolic pressure was defined as the alternans threshold. Electrical alternans was detected by comparing the ST-T area in the surface ECG (lead II) on alternate beats. RESULTS: The alternans threshold was 305(s.e.m. 10.4) ms under control conditions and decreased to 271(12.1), 225(33.4), and 177(6.2)ms, as the frequency of left stellate stimulation was increased to 1, 2, and 5 Hz, respectively (P < 0.001). Tau and peak -dp/dt began to alternate at the same pacing cycle length as peak +dp/dt and peak systolic pressure. Electrical alternans was only observed during mechanical alternans and the ST-T area of the strong beat was 243(143)% greater than the ST-T area of the weak beat (P < 0.001). Timolol (1 mg.kg-1) blocked the effect of left stellate stimulation (1 and 2 Hz) on mechanical and electrical alternans. CONCLUSIONS: Left sympathetic activation causes a frequency-dependent reduction in the threshold cycle length for global mechanical and electrical alternans. Alternation in relaxation occurs at the same pacing cycle length as does alternation in contraction. Repolarization alternans in the surface ECG appears to reflect underlying mechanical events.
Animals↗
[Role of Leptotrombidium (L.) scutellare in transmission of human diseases].
A series of cases of hemorrhagic fever with renal syndrome (HFRS) in Shaanxi province and autumn-type tsutsugamushi disease in Jiangsu province were studied during 1988 to 1990 and 1986 to 1993 to explore the role of Leptotrombidium (L.) scutellare in transmission of these diseases. Results showed that L. (L.) scutellare is a dominant strain of mites inhabiting in rats and its seasonal fluctuation conformed to the seasonal distribution of these diseases. L. (L.) scutellare could naturally infect with HFRS virus and Rickettsia tsutsugamushi and transmit them by stinging and transovarial route. It indicated that L. (L.) scutellare could be a vector in transmission of HFRS and autumntype tsutsugamushi disease.
Animals↗
The role of Leptotrombidium scutellare in the transmission of human diseases.
OBJECTIVE: To investigate the role of Leptotrombidium (L.) scutellare in the transmission of hemorrhagic fever with renal syndrome (HFRS) and tsutsugamushi disease of autumn-type. MATERIALS AND METHODS: Four criteria were used to ascertain this mite as transmitting vector of disease: (1) epidemiological evidence; (2) natural infection of pathogen; (3) ability to transmit pathogen via biting; (4) ability to transfer pathogen via transovarian route. RESULTS: The results indicated that L. scutellare was the dominant species of chigger mite on rats. Its seasonal distribution was correlated with the incidence of these two diseases. This mite could be naturally infected by HFRS virus (HFRSV) and Rickettsia tsutsugamushi (Rt) and the mite could transmit HFRSV and Rt to vertebrates by biting and to its offspring via transovarian transmission. CONCLUSIONS: These results have proved that L. scutellare can be a transmitting vector of HFRS and tsutsugamushi disease of autumn-type.
Animals↗
An epidemiological survey on use and abuse of antianxiety drugs among Beijing residents.
OBJECTIVE: To investigate the current trend of use and abuse of antianxiety drugs in Beijing residents in 4 urban and 2 rural areas. METHODS: A cluster sampling household survey of 6567 subjects out of 3000 families was made by 6 local grass roots mental health centers collaboratively. Screened with designed questionnaire, the positive addicted subjects were examined with present state examination (PSE), eysenck personality questionnaire (EPQ) and social disability screening schedule (SDSS) to detect their psychosocial status. RESULTS: Benzodiazepine (BZD) has been widely prescribed and the rate of usage for 1 year is 61.82/1000, whereas the rate of dependence is 16.29/1000, constituting 1/4 of long-term users. This study also indicates that Valium is a most preferred drug among all available BZD used by the majority of addicted subjects. CONCLUSIONS: It is concluded that the reported dependence is not epidemic but iatrogenic in nature attributable to persistent misuse of BZD. It is stressed that guideline of rational clinical application of BZD should be laid down so as to markedly reduce further possible misuse and abuse of the drugs of this kind.
Adolescent↗
[Reconstitution of Hu-SCID mice transplanted with human tonsillar lymphocytes immunized with dengue virus-2 in vitro and its immune response].
OBJECTIVE: To study the measure for the reconstitution of severe combined immunodeficient disease mice (SCID mice) transplanted with human lymphocytes immunized with specific antigen in vitro. METHODS: Hu-SCID mice were constructed by intraperitoneal (i.p.) transfer of human tonsillar lymphocytes (TLC) first immunized with dengue virus-2 (DV2) in vitro, then boostered with different doses of DV2 antigen in vivo. RESULTS: Human immunoglobulin (Ig) and specific human anti-DV2 antibodies could be detected in sera of the hu-SCID mice by ELISA. Two weeks after transplantion of the in vitro-immunized hu-TLC, the highest human IgG concentration was 412.86 micrograms/ml, two or four weeks later specific human anti-DV2 IgM or IgG and the neutralizing antibody could found in these sera, respectively, the highest titer was 1:6400. The levels of human IgG and human anti-DV2 antibodies were related to the dose of DV2 antigen. The presence of human B cells (CD20+) and T/cells (CD3+, CD4+, CD8+) were shown in the sleen, lung, intestine and mesentery of the hu-SCID mice as determined by immunoperoxidase staining, and the cells were distributed correspondingly with the lymphocyte cells in proper human tissue. Human anti-DV2 IgG could also be detected in the spleen cell culture obtained from the SCID mice. CONCLUSION: By co-immunized in vitro and in vivo the SCID mice deduced stronger immune response for specific antigen, and the reconstitution of the human lymphocytes could be established successfully.
Animals↗
[Studies on MDM2 oncogene expression and its effect on pancreatic carcinoma cells].
In order to study the interrelation and interaction between MDM2 oncogene and wild type p53 in human pancreatic cancer, we studied the expression and amplification of MDM2 oncogene and its antagonistic effect on wild type p53 by use of gene recombination, gene transduction and molecular hybridization techniques. The results showed that MDM2 oncogene could be detected in all 5 pancreatic cell lines, but MDM2 mRNA expression varied in the different cell lines. The recombinant vector pCMV-MDM2 was transduced into PC-2/s-wtp53 cell line (a transformed PC-2 pancreatic carcinoma cell line containing wild type p53 gene). The resultant cell line, PC-2/s-wtp53/pCMV-MDM2 showed rapid cell growth, a rate similar to that of the parent cell line PC-2. Our results verify the fact that MDM2 gene can abrogate the cell growth arrest mediated by wild type p53 and the antagonistic function of wild type p53.
Adenocarcinoma↗
[Possible mechanisms for reduced endothelium dependent responsiveness to norepinephrine in isolated aorta of rats with peritonitis shock].
Various antagonists were used to analyze the possible factors contributing to the reduced endothelium-dependent response to norepinephrine in isolated aorta of rats with peritonitis shock. The concentration-effect curves to norepinephrine in the aortic rings with endothelium pretreated by methyl blue, atropine, anisodamine and indomethacin were shift to the left and the largest contraction was raised. The concentration-effect curve to norepinephrine was also shift to the left and the largest contraction was raised in the aortic ring with endothelium pretreated by propranolol. However, the similar changes were also observed in rings without endothelium pretreated by propranolol. While the concentration-effect curves to norepinephrine were shift to the right and the largest contraction reduced in rings with or without endothelium that pretreated by Yohimbine. The results suggested that the reduced endothelium-dependent responsiveness to norepinephrine in the isolated aorta of rats with peritonitis shock may involve various factors of which vasodilatation mediated by cGMP may be the one of importance.
Animals↗