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Biomedical subjects

L He

Publications and source records attributed to L He.

At least 199 records · Page 11Linked to original sources
PubMed2000

[Observation of biofilms inside tracheal tubes by electron microscopy and the relationship between biofilms and VAP].

OBJECTIVE: To observe the formation of biofilms inside tracheal tubes and to evaluate the effect of biofilm on the development of ventilator associated pneumonia (VAP). METHODS: Biofilms inside tracheal tubes from intubated patients were observed by scanning electron microscopy and transmission electron microscopy, meanwhile bacteria were detected in the specimens from the lower respiratory tract and the inside of tracheal tubes. RESULTS: 76% (19/25) of inner surface of tracheal tubes was coated with a confluent amorphous matrix by scanning electron microscopy. The average duration of trach-intubation in this group [(10.7 +/- 7.9) days] was longer than that in the other group [(2.1 +/- 0.8) days] in which tracheal tubes were not coated with the confluent amorphous matrix (P < 0.05). The presence of many bacteria(14/18) within these amorphous matrix was confirmed by transmission electron microscopy. Of the sixteen tracheal tubes, eleven tubes grew the same organisms that had been isolated from the secretions of the lower respiratory tract before extubation. In some VAP patients (7/8), organisms isolated from tracheal tubes were the same organisms which were pathogenic organisms of VAP. CONCLUSIONS: There was a close connection between the formation of bacterial BF and the long-term indwelling tracheal tubes. The presence of bacterial BF in the inner of tracheal tubes might be associated with the pathogenic organisms of VAP.

Adult↗
PubMed2000

[Influence of the subglottic secretion drainage on the morbidity of ventilator associated pneumonia in mechanically ventilated patients].

OBJECTIVE: To assess the influence of the subglottic secretion drainage on the morbidity of ventilator associated pneumonia in mechanically ventilated patients. METHODS: All cases requiring intubation in SICU were intubated with a special type endotracheal tube which has a small-bore cannula in its wall for subglottic secretion drainage. They were randomly divided into two groups received subglottic secretion drainage(SSD) and usual care(NON-SSD) respectively. Bacterial culture of samples from the oropharynx, subglottic secretions and lower respiratory tract were obtained periodically. The amount of subglottic secretion aspirated daily, ventilated days and the number of cases with VAP were recorded. Etiologic diagnosis of VAP was based on the quantitative bacterial culture of secretions obtained by protected specimen brush(PSB). RESULTS: The morbidity of VAP in the SSD group (n = 35) (23%) was lower than that in the NON-SSD group (n = 33) (45%) (P < 0.05). The difference was due to the significant reduction of VAP caused by gram-positive cocci and Haemophilus influenzae organisms. However, no difference was observed in the incidence of VAP caused by non-fermental bacteria. After intubation the onset of VAP was delayed in SSD group (14 +/- 8 day) as compared with the NON-SSD group (6 +/- 4 day) (P < 0.05). The same organisms were isolated by PSB among 61% (14/23) patients with VAP as what were previously isolated from the subglottic secretions. CONCLUSIONS: The presence of subglottic secretion may be an origin of the pathogenetic organisms of VAP. The morbidity of VAP in mechanically ventilated patients can be reduced by SSD, especially for VAP caused by gram-positive cocci and Haemophilus influenzae organisms. SSD may be a simple and effective method for prevention of VAP.

Glottis↗
PubMed2000

[Changes of elastase in gingival crevicular fluid after periodontal treatment of adult periodontitis patients].

OBJECTIVE: To examine the changes of elastase in the supernatant (EA-s) and in the pellet (EA-p) after centrifuge in gingival crevicular fluid (GCF) before and after periodontal treatment. METHODS: GCF was sampled with filter paper strips by intra-pocket method to determine EA levels. Forty-three teeth of eight subjects were included. EA-s and EA-p were determined separately using the subtract Meosuc-ala-ala-val-pro-NA. RESULTS: EA-s per site and per ml, EA-p per site and the ratio of EA-s/EA-p (S/P) decreased significantly after non-surgical periodontal treatment (P < 0.001), while EA-p concentration didn't change (P > 0.05). CONCLUSIONS: GCF-EA-s and EA-p could act as objective parameters to evaluate the effect of periodontal therapy, especially EA-s and S/P, which may be sensitive diagnostic parameters for determining periodontal disease activity.

Adult↗
PubMed2000

[Anisodamine in prevention and treatment of sepsis of severely burned patients].

OBJECTIVE: To observe the preventive effect of anisodamine on possible sepsis of patients with major burns and the effect of anisodamine on patients with sepsis. METHODS: Forty-two patients with extensive burn admitted to our burn institute from April 1998 to November 1999 were divided randomly into two groups: treatment group (T group) and control group (C group). In the T group, all 20 patients received fluid resuscitation regimen with anisodamine, and in the C group, 22 patients received the regimen with no anisodamine. A tonometry catheter was positioned in the stomach, connecting with the automatic gas analysis machine (Datex-Engstrom Corporation, Dutch) for determining gastric intramucosal pH (pHi). The plasma concentrations of diamine oxidase (DAO) and endotoxin were measured. Correlation analysis between pHi, DAO and endotoxin were made respectively during early stage of postburn. All the parameters in 7 patients with sepsis before and after administration of anisodamine were compared with those in 6 patients with sepsis without use of anisodamine. RESULTS: The incidence of sepsis in the T group was lower (20.0%) than that in C group (40.9%). The gastric pHi value in the early period of postburn was significantly higher in the T group than in the C group (P < 0.05). Concurrently, the plasma concentrations of DAO and endotoxin were significantly lower in the T group than in the C group (P < 0.05 or 0.01). A significant negative correlation was seen between the gastric pHi and respective values of DAO, endotoxin (P < 0.05 or 0.01). There were a decrease in gastric pHi, and an increase in plasma DAO and endotoxin level in patients with septic episode; however all the parameters after administration of anisodamine were improved compared with those in septic patients without use of anisodamine. CONCLUSIONS: Intestinal ischemic injury plays an important role in provoking sepsis during early postburn period. Anisodamine is effective in restoring intestinal circulation both in the shock phase and after the development of sepsis.

Adolescent↗
PubMed2000

[The effect of escharectomy during burn shock stage on the expression of ICAM-1 and TNF-alpha mRNA of rat pulmonary tissue].

OBJECTIVE: To study the rules of postburn expression of IGAM-1 and TNF-alpha and the rule of the change in the MPO activity in pulmonary tissue; to explore the influence of escharectomy on the changes in the above indices and to clarify the importance of escharectomy during shock stage. METHODS: One hundred and seventy six Wistar rats with 30% TBSA III degree back scald were used. RT-PCR was used in the examination of the expression of pulmonary tissue ICAM-1 and TNF-alpha mRNA and of the change in pulmonary MPO activity after escharectomy. RESULTS: The expressions of pulmonary ICAM-1 and TNF-alpha mRNA began to increase at 4 hour postburn and reached peak level at 12 and 24 hours postburn, respectively. Their expressions returned to near control level 96 hours postburn in rats undergone escharectomy during shock stage. On the contrary, they remained at a relative high level even on 7th postburn day in both non-operated rats and the rats receiving escharectomy 96 hours postburn. In addition, pulmonary tissue MPO activity fell to near control level in rats undergone escharectomy during shock stage, but it maintained a high level in rats in which escharectomy was not done during shock stage. CONCLUSION: These findings suggest that eschar could induce the production of endothelial adhesion molecules. Therefore escharectomy as early as possible is very important to prevent the expression and release of adhesion molecules and the development of SIRS.

Animals↗
PubMed2000

[Effect of xanthone from Canscora lucidissima on cultured myocytes anoxia-reoxygenation injuries].

The anoxia/reoxygenation model of cultured neonatal rats myocardial cells were developed, according to Laarse's method: anoxia and glucose deficiency for 60 min followed by reoxygenation and re-exposure to glucose for 30 min. The results showed that the survival rate of myocardial cells in the anoxia group was significantly decreased, release of lactate dehydrogenase (LDH) from myocytes was increased and membrane fluidity was decreased, all the changes were much more severe in the reoxygenation group. 30 min before anoxia, addition of xanthones: 1,8-dihydroxy-3, 5-dimethoxyxanthone, 1-hydroxy-3,5-dimethoxyanthone and 1-hydroxy-3,7,8-trithoxyxanthone, isolated from Canscora lucidissima increased the rate of myocardial cells and membrane fluidity, decreased the release of LDH. These results suggested that xanthone may provide some protective effects on the anoxia/reoxygenation damages on myocardium.

Animals↗
PubMed2000

[Studies on the infrared spectra of clusters containing O3MoS3, [Mo(x) (CO)y(O,S-C6H4-1,2)3FezLm]n- (x = 1,2 or 3, y = 0,3,7 or 4, z = 0 or 1, L = Cl, m = 0,2, n = 1 or 2) unit and the relationship between the spectra and their structures].

The IR spectra of clusters containing O3MoS3 Unit, (Et4N) [Mo(O, S-C6H4-1,2)3](1), (Et4N)2[Mo2(CO)3(O,S-C6H4-1,2)3](2), (Et4N)2[Mo3(CO)7(O,S-C6H4-1,2)3](3) and (Et4N)2[Mo2(CO)4(O,S-C6H4-1,2)3FeCl2](4) have been investigated. The characteristic frequencies, nu (Mo(n+)-OtR) (n = 4,5), nu (Mo(n+)-ObR) (n = 0,4), nu (Mo(n+)-StR) (n = 4,5), nu (Mo(n+)-SbR)(n = 0,1,4), nu (C = O), nu (Mo(n+)-C)(n = 0,1), delta (Mo(n+)-C-O)(n = 0,1), nu (Fe(2+)-ObR) and nu (Fe(2+)-Cl) were assigned by comparing the vibrational frequencies and structure parameters of them with that of Mo-Fe-S clusters. The influences of sigma donor abilities of ligands L(-OR, -SR) on nu (Mo-C) and nu (C = O) and the effect of Mo(n+)-->Mo4+ (n = 0,1) charge transfer on nu (Mo(4+)-ObR), nu (Mo(n+)-C) and nu (C = O) have been discussed. A partial oxidation of cluster 4 to [Mo2(CO)3(O,S-C6H4-1,2)3]- (5) have been inferred according to the information from the changes of IR spectra of cluster 4 in air with time and the existence of cluster 5 was also verified by NFAB-MS of cluster 4.

English Abstract↗
PubMed2000

[IR search through Internet].

In our laboratories, we have almost had the complete Sadtler IR database, about 133,000 spectra. Based on Sadtler IR Search Master software, off-line spectrum search through internet has been set up in this work. Customers e-mail their unknown spectra as attached files to ftir2000@sina.com or ftir@microchem.org.cn. After we download the unknown spectra and search them, we will send the search reports in Microsoft Word format back to the customers within 72 hours. Please visit our web site www.microchem.org.cn to know the policy about our IR search program.

Databases, Factual↗
PubMed1999

Characterization of the Taxol binding site on the microtubule. Identification of Arg(282) in beta-tubulin as the site of photoincorporation of a 7-benzophenone analogue of Taxol.

Photoaffinity labeling methods have allowed a definition of the sites of interaction between Taxol and its cellular target, the microtubule, specifically beta-tubulin. Our previous studies have indicated that [(3)H]3'-(p-azidobenzamido)Taxol photolabels the N-terminal 31 amino acids of beta-tubulin (Rao, S., Krauss, N. E., Heerding, J. M., Swindell, C. S., Ringel, I., Orr, G. A., and Horwitz, S. B. (1994) J. Biol. Chem. 269, 3132-3134) and [(3)H]2-(m-azidobenzoyl)Taxol photolabels a peptide containing amino acid residues 217-233 of beta-tubulin (Rao, S., Orr, G. A., Chaudhary, A. G., Kingston, D. G. I., and Horwitz, S. B. (1995) J. Biol. Chem. 270, 20235-20238). The site of photoincorporation of a third photoaffinity analogue of Taxol, [(3)H]7-(benzoyldihydrocinnamoyl) Taxol, has been determined. This analogue stabilizes microtubules polymerized in the presence of GTP, but in contrast to Taxol, does not by itself enhance the polymerization of tubulin to its polymer form. CNBr digestion of [(3)H]7-(benzoyldihydrocinnamoyl)Taxol-labeled tubulin, with further arginine-specific cleavage by clostripain resulted in the isolation of a peptide containing amino acid residues 277-293. Amino acid sequence analysis indicated that the photoaffinity analogue cross-links to Arg(282) in beta-tubulin. Advances made by electron crystallography in understanding the structure of the tubulin dimer have allowed us to visualize the three sites of photoincorporation by molecular modeling. There is good agreement between the binding site of Taxol in beta-tubulin as determined by photoaffinity labeling and electron crystallography.

Animals↗
PubMed1999

Participation of the liver in generation of a vigorous anti-donor response after inoculation of donor spleen cells.

BACKGROUND: There is a general agreement that a preferential accumulation of alloantigens within the liver could induce hyporesponsiveness to the inoculated antigens. Entrapment of antigens in the liver may evoke an unique immune response in the organ and play a key role in determination of the fate of the transplanted grafts. To understand the immune response in the liver after inoculation of allogeneic donor antigens, we examined the immune response to systemically inoculated alloantigen in rats whose sensitized liver was replaced with that of naive rats or in naive rats whose liver was replaced with that of sensitized rats. METHODS: Using implantation of syngeneic liver (alloantigen-accumulated/naive) in rats (naive/alloantigen-sensitized), we compared the immune responses to alloantigen between rats with hepatic/extrahepatic alloantigen at 24 hr after alloantigen inoculation. This was called sensitized-liver-grafted (SLG)/sensitized-liver-removed (SLR) treatment. The immune response to donor alloantigen in this model was evaluated by survival of skin or heart grafts, complement-dependent cytotoxicity (CDC) titer and delayed-type hypersensitivity (DTH) response. RESULTS: Compared with the mean survival time (MST) in donor spleen cell inoculated (DSI) rats (skin and heart, MST: 8.2+/-1.1 and 10.7+/-2.3 days), SLG rats rejected allografts in an accelerated fashion (skin and heart, MST: 5.5+/-0.5 and 4.2+/-0.8 days), associated with higher CDC titer and DTH response. In contrast, allograft survival was moderately prolonged in SLR (skin and heart, MST: 16.5+/-2.6 and 29.5+/-3.7 days) associated with suppressed CDC titer and DTH response. The survival of third-party allograft after SLG or SLR treatment (skin, MST: 9.3+/-1.5 or 9.7+/-0.6 days) indicated that immunological hyper/hyporesponsiveness was donor-specific. CONCLUSIONS: A strong anti-donor immune response was induced by the transfer of donor antigen-baring liver to naive rats 24 hr after alloantigen inoculation, whereas removal of the liver suppressed alloimmune response. Our results indicate that vigorous anti-alloimmune response occurred in the liver after systemic inoculation of donor spleen cells.

Adoptive Transfer↗
PubMed1999

Examination of ionic liquids and their interaction with molecules, when used as stationary phases in gas chromatography.

Stable room-temperature ionic liquids (RTILs) have been used as novel reaction solvents. They can solubilize complex polar molecules such as cyclodextrins and glycopeptides. Their wetting ability and viscosity allow them to be coated onto fused silica capillaries. Thus, 1-butyl-3-methylimidazolium hexafluorophosphate and the analogous chloride salt can be used as stationary phases for gas chromatography (GC). Using inverse GC, one can examine the nature of these ionic liquids via their interactions with a variety of compounds. The Rohrschneider-McReynolds constants were determined for both ionic liquids and a popular commercial polysiloxane stationary phase. Ionic liquid stationary phases seem to have a dual nature. They appear to act as a low-polarity stationary phase to nonpolar compounds. However, molecules with strong proton donor groups, in particular, are tenaciously retained. The nature of the anion can have a significant effect on both the solubilizing ability and the selectivity of ionic liquid stationary phases. It appears that the unusual properties of ionic liquids could make them beneficial in many areas of separation science.

Chromatography, Gas↗
PubMed1999

Mosaic allelic insulin-like growth factor 2 expression patterns reveal a link between Wilms' tumorigenesis and epigenetic heterogeneity.

Numerous observations link the loss of imprinting of insulin-like growth factor 2 (IGF2) and an overdosage of this growth factor gene with cancer, in general, and with Wilms' tumorigenesis, in particular. It is not known, however, if loss of imprinting correlates with specific stages of neoplasia or if allelic expression patterns vary within the tumor. By applying an allele-specific in situ hybridization technique to formalin-fixed thin sections, we show that the parental IGF2 alleles can be differentially expressed, not only in Wilms' tumors, but also in nephrogenic rests (which represent premalignant lesions) of Wilms' tumor patients. Moreover, a subpopulation of mesenchymal cells, which surrounds tumor nodules, expresses IGF2 biallelically irrespective of the imprinted state of IGF2 within the tumor. These data show that Wilms' tumorigenesis involves epigenetic heterogeneity as visualized by variable allelic IGF2 expression patterns.

Alleles↗
PubMed1999

Isolation and structure of SCH 351633: a novel hepatitis C virus (HCV) NS3 protease inhibitor from the fungus Penicillium griseofulvum.

A new hepatitis C virus (HCV) protease inhibitor designated as Sch 351633 (1) was isolated from the fungus, Penicillium griseofulvum. Structure elucidation of 1 was accomplished by analysis of spectroscopic data, which determined compound 1 to be a bicyclic hemiketal lactone. Compound 1 exhibited inhibitory activity in the HCV protease assay with an IC50 value of 3.8 microg/mL.

Antiviral Agents↗
PubMed1999

Prostate cancer expression profiling by cDNA sequencing analysis.

Prostate cancer is a frequently diagnosed solid tumor that is originated mostly from prostate epithelium. One of the key issues in prostate cancer research is to develop molecular markers that can effectively detect and distinguish the progression and malignancy of prostate tumors. Automated, single-pass cDNA sequencing was utilized to rapidly identify expressed genes in a number of cDNA libraries constructed from various normal and tumor prostatic tissues. These included cell lines as well as short-term epithelial culture. A total of 6604 expressed sequence tags (ESTs) were generated and searched against on-line nucleotide and protein databases. A relational database centric software system was constructed to process, store, and analyze EST data rapidly. cDNA contigs were also obtained by assembly of multiple EST sequences. Protein structural signatures were annotated using motif analysis tools including BLOCKS and an in-house-designed neural network. Cross-library comparisons revealed their unique gene expression profiles. Several differentially expressed cDNA clones were identified, and their expression patterns were confirmed by RNA dot blot and RT-PCR analyses.

Cell Line↗
PubMed1999

[Study on HBV preS/S gene mutation in peripheral blood mononuclear cells].

OBJECTIVE: To study the significance of mutations of HBV preS and S genes in peripheral blood mononuclear cells (PBMC). METHODS: Srea and PBMCs of 19 chronic hepatitis B patients were collected. The S, preS1 and preS2 gene fragments of HBV were separately amplified by PCR, and 5 cases of preS1 and preS2 gene fragments in paired sera and PBMC were sequenced. RESULTS: The positive rates of S, preS1 and preS2 gene fragments in serum and PBMC were 100%, 94.7%, 100% and 0, 26.3%, 26.3% respectively. Sequence analysis of preS1 and preS2 genes showed that in 8/10 specimens there were point mutations in preS1 and 7/10 mutations in preS2; while in the others (2 of preS1 and 3 of preS2) the sequences were identical to that of wild-type HBV. CONCLUSION: No full-length HBV genome in PBMC was detected by PCR, this is a fact not supporting that HBV can replicate, assemble and release from PBMC. The amino acid changes predicted mutatieds from nucleotide were focused in aa21-47 region, which might affect adsorption and penetration of HBV, and alteration in tissue tropism. Whether the presence of HBV subgenomic fragments in PBMC can affect cell function should be pursued.

Base Sequence↗
PubMed1999

Pretreatment of crude pancreatic islets with mitomycin C prolongs graft survival time in xenogeneic rat-to-mouse model.

BACKGROUND: Rejection of pancreatic islet grafts is still a serious problem. We evaluated the effect of mitomycin C (MMC) on the survival of crude islets grafts after xenogeneic islet transplantation. METHODS: WS (RT1k) rat islets pretreated with various concentrations of MMC (0, 1, 3.2, 10, 32, 50, 100, 320, and 1,000 microg/ml) were transplanted into C57BL/6 mice with streptozotocin-induced diabetes. In vivo graft function was assessed by a daily measurement of nonfasting blood glucose concentration in each animal. We also examined the separate effect of MMC on purified islets and contaminants present in the crude islet preparation. RESULTS: MMC at doses of 10, 32, 50, and 100 microg/ml resulted in a significant prolongation of the mean graft survival time from a control of 12.4+/-2.5 days to 23+/-7.4, 17.5+/-5.4, 25.5+/-14.7, and 26.7+/-8.9 days, respectively. Deterioration of glucose metabolism was noted when the dose exceeded 32 microg/ml, whereas at 320 microg/ ml, MMC failed to restore normoglycemia. Prolongation of survival time of crude islets was the result of its effect on islets and contaminant components of the crude islet preparation. In vitro study showed that MMC treatment at a higher concentration than 10 microg/ml reduces the stimulatory as well as proliferative capacity of lymph node cells. CONCLUSIONS: Pretreatment of pancreatic islets with MMC at 10 microg/ml prolongs xenograft survival without deterioration of in vivo graft function. This novel treatment modality represents a new strategy for the modulation of immunity of islets and contaminants in crude islet preparations.

Animals↗