Biomedical subjects

L Guo

Publications and source records attributed to L Guo.

At least 91 records · Page 5Linked to original sources

PubMed2001

Matrix metalloproteinases 2 and 9 in otitis media with effusion.

A qualitative and quantitative study of the presence of matrix metalloproteinase 2 (MMP 2) and matrix metalloproteinase 9 (MMP 9), in the effusions of otitis media with effusion (OME), was performed. The activity of the above enzymes was compared in thick and thin effusions, and concentrations compared in samples from children with one, two, three and four sets of ventilation tubes. The activity of both MMP 2 and MMP 9 was higher in thick than thin effusions, P = 0.07 and P = 0.04, respectively. The concentrations of MMP 9 did not vary with the number of tube insertions but those of MMP 2 did (ANOVA P < 0.05). MMPs may be involved in tympanic membrane damage and prognosis of OME.

Child↗

PubMed2001

Artificial ion channels formed by a synthetic cyclic peptide.

A new cyclic peptide 1 having an (LLLD)3 configuration pattern was designed that is capable of forming artificial transmembrane ion channels by self-assembly of planar peptide rings, with hydrophilic groups arrayed in the interior of the channel. Ion permeability in the presence of the synthetic peptide 1, cyclo[-Trp-Dap-Leu-D-Ala-Trp-Ser-Val-D-Ala-Trp-Ser-Ile-Gly-] (Dap: L-diaminopropionic acid), was observed in lipid bilayer membranes. The pH dependence of ionic conductance showed that the beta-amino group of Dap may play a role in the conductance of the peptide channels. Fourier-transform infrared and circular dichroism data imply that, in a membrane, a stack of cyclic peptides is formed in which the inter peptide H bonds form a kind of beta-structure analogous to that in the gramicidin A dimer and distinct from the H-bonding pattern of the beta-barrels.

Circular Dichroism↗

PubMed2001

Goblet cell carcinoid of the appendix: Investigation of the expression of beta-catenin and E-cadherin.

Goblet cell carcinoids are rare neoplasms that predominantly occur in the appendix. In this report we present a case of goblet cell carcinoid of the appendix. A 58-year-old male patient complaining of pain in the right lower quadrant was diagnosed with acute appendicitis and underwent an appendectomy. Histological examination of the resected appendix revealed goblet cell carcinoid. Infiltration of tumor cells beyond the appendix was observed and the surgically resected margin was positive for tumor cells. Carcinoembryonic antigen (CEA) was diffusely detected by immunohistochemistry, and cytokeratin 20, neuron-specific enolase (NSE), chromogranin A and serotonin were focally observed in the tumor cells. The expression of beta-catenin and E-cadherin was investigated to compare with that of typical rectal carcinoids (n = 3) and colon adenocarcinomas (n = 3). In normal colonic and rectal mucosae, beta-catenin and E-cadherin stained positive on the plasma membrane. In the case reported here, beta-catenin showed a preserved expression on the plasma membrane of goblet cell carcinoid; a pattern similar to typical carcinoids rather than to adenocarcinomas. However, E-cadherin demonstrated a reduced expression on the plasma membrane of the tumor cells. This staining pattern was identical to those both of carcinoids and of adenocarcinomas. These findings suggest the possibility that, in some cases, the adherens junctions of goblet cell carcinoids are similar to those of typical carcinoids rather than to those of adenocarcinomas.

Appendix↗

PubMed2001

Adult-onset herpes simplex virus hepatitis with diffuse myofibroblastic transformation of hepatic stellate cells (Ito cells) in non-necrotic areas.

The myofibroblastic transformation of hepatic stellate cells (HSC; also known as Ito cells) usually occurs following necrosis of adjacent liver cells. No report has previously found that such a transformation occurs in herpes simplex virus (HSV) hepatitis. We present an autopsy case of HSV hepatitis with myofibroblastic transformation of HSC that is different from the usual transformation of HSC. The patient was a 66-year-old woman who had received various therapies for cutaneous T-cell lymphoma. An autopsy revealed submassive hepatic necrosis with hemorrhage due to HSV hepatitis. HSV infection was confirmed by DNA in situ hybridization in liver tissue. Immunohistochemical staining for alpha-smooth muscle actin (ASMA) showed a strong positive reaction in almost all of the HSC in non-necrotic areas. However, in necrotic areas, the HSC were completely negative for ASMA. These findings indicate that not only liver cells but also HSC can become necrotic in HSV hepatitis. In contrast, in non-necrotic areas, almost all of the HSC showed active transformation to myofibroblasts.

Actins↗

PubMed2001

Expression of CD9/motility-related protein 1 (MRP-1) in renal parenchymal neoplasms: consistent expression in papillary and chromophobe renal cell carcinomas.

CD9 is a glycoprotein that is abundant in hematopoietic cells. Recently, it has been reported that CD9 is also present in the human kidney. In this article, we investigated the expression of CD9 using an immunohistochemical technique. We also studied the expression of CD9 protein and messenger RNA (mRNA) in tissue samples of some renal tumors using immunoblotting and reverse-transcription polymerase chain reaction (RT-PCR) analysis. Immunohistochemically, all tumors of papillary and chromophobe renal cell carcinomas (RCCs) and oncocytomas expressed CD9. In addition, CD9 was expressed in 31 of 66 conventional RCCs and 1 of 4 collecting duct carcinomas. On immunoelectron microscopy, CD9 was identified on the plasma membrane of a conventional RCC. The presence of CD9 protein in normal kidneys and various renal tumors, except for a collecting duct carcinoma and an oncocytoma, was confirmed by immunoblotting. On RT-PCR analysis, the expression of CD9 mRNA was observed in 1 normal kidney, 2 conventional RCCs, and 1 oncocytoma. The frequency of immunohistochemical CD9 positivity was significantly higher in papillary and chromophobe RCCs than in collecting duct carcinomas and conventional RCCs, respectively. These results suggest that CD9 may be a beneficial marker in the differential diagnosis between papillary RCCs and collecting duct carcinomas and also between chromophobe and conventional RCCs.

Adult↗

PubMed2001

Screening for CRX gene mutations in Chinese patients with Leber congenital amaurosis and mutational phenotype.

PURPOSE: To screen for possible disease-causing mutations in the CRX gene in Chinese patients with Leber congenital amaurosis (LCA) and to enrich the understanding of its mutational phenotype. METHODS: Genomic DNA was collected from 27 patients with LCA. The coding sequences of the CRX gene were analyzed using the PCR-heteroduplex-SSCP method. Mutations were confirmed by DNA sequencing. RESULTS: We identified two heterozygous variations in the CRX gene in two patients with LCA. One was a deletion (GCC-->-CC, A181D1bp) leading to a frameshift and protein truncation. This mutation was present in a patient with LCA, but not in his healthy parents. The ocular manifestations of this A181Delta1bp mutation are described. An intronic variation (IVS1-13G-->C) was found in a patient with LCA as well as in his healthy father. CONCLUSION: A heterozygous A181D1bp mutation in the CRX gene caused an LCA phenotype in a Chinese patient.

Asian People↗

PubMed2001

EXAFS study on the local atomic structures around iron in glycosylated haemoglobin.

Samples with 5.1%, 9.8% and 15.3% HbA1c were extracted from normal subjects and patients with slight and serious diabetes respectively. Extended x-ray absorption fine structure spectra of Fe K absorption were collected at the EXAFS experimental station of the Beijing Synchrotron Radiation Facility. The step-by-step fluorescent mode was employed with a count time of 10 s per point. Several independent scans were averaged to eliminate the statistical noise. Reference backscattering amplitudes and phaseshifts were calculated using the curve wave theory (FEFF code) of EXAFS. Apart from the nitrogen neighbours around the central iron atom, oxygen neighbours are also found. The Fe-N bond length increases by about 0.02 A for the sample with 15.3% HbA1c compared with the others, but the Fe-O bond length is almost unchanged. With increasing of HbA1c concentration, the content of Hb increases and the content of HbO2 decreases. This demonstrates that the glycosylation of haemoglobin will decrease its ability to carry oxygen.

Absorptiometry, Photon↗

PubMed2001

Paxillin: application of immunohistochemistry to the diagnosis of chromophobe renal cell carcinoma and oncocytoma.

Paxillin is a cytoskeletal protein that was recently identified as a component of focal adhesions and links between F-actin and integrin. In this study, 91 renal tumors--65 conventional renal cell carcinomas (RCCs), 14 papillary RCCs, 6 chromophobe RCCs, 4 collecting duct carcinomas, 2 oncocytomas--were investigated for the immunohistochemical expression of paxillin. In a normal kidney, paxillin was predominantly expressed in the cytoplasm of distal tubules, loops of Henle, collecting ducts, and vascular smooth muscle cells. In all of the chromophobe RCCs and oncocytomas, strong expression of paxillin was observed in the tumor cytoplasm. In contrast to these tumors, conventional RCCs, papillary RCCs, and collecting duct carcinomas showed negative reactions for paxillin except for one case in each subgroup with weak reactivity. An immunoblot analysis confirmed the presence of paxillin in healthy kidney, chromophobe RCC, and oncocytoma. These data suggest that paxillin possibly plays a role in signal transductions as a focal adhesion intervening between tumor cells and the extracellular matrix in renal tumors with collecting duct phenotypes such as chromophobe RCCs and oncocytomas, but not in conventional RCCs. In addition, paxillin may be an available marker in distinguishing chromophobe RCCs from conventional or papillary RCCs.

Adenoma, Oxyphilic↗

PubMed2001

Improved efficacy of ciprofloxacin administered in polyethylene glycol-coated liposomes for treatment of Klebsiella pneumoniae pneumonia in rats.

Animal and clinical data show that high ratios of the area under the concentration-time curve and the peak concentration in blood to the MIC of fluoroquinolones for a given pathogen are associated with a favorable outcome. The present study investigated whether improvement of the therapeutic potential of ciprofloxacin could be achieved by encapsulation in polyethylene glycol (PEG)-coated long-circulating sustained-release liposomes. In a rat model of unilateral Klebsiella pneumoniae pneumonia (MIC = 0.1 microg/ml), antibiotic was administered at 12- or 24-h intervals at twofold-increasing doses. A treatment period of 3 days was started 24 h after inoculation of the left lung, when the bacterial count had increased 1,000-fold and some rats had positive blood cultures. The infection was fatal within 5 days in untreated rats. Administration of ciprofloxacin in the liposomal form resulted in delayed ciprofloxacin clearance and increased and prolonged ciprofloxacin concentrations in blood and tissues. The ED(50) (dosage that results in 50% survival) of liposomal ciprofloxacin was 3.3 mg/kg of body weight/day given once daily, and that of free ciprofloxacin was 18.9 mg/kg/day once daily or 5.1 mg/kg/day twice daily. The ED(90) of liposomal ciprofloxacin was 15.0 mg/kg/day once daily compared with 36.0 mg/kg/day twice daily for free ciprofloxacin; 90% survival could not be achieved with free ciprofloxacin given once daily. In summary, the therapeutic efficacy of liposomal ciprofloxacin was superior to that of ciprofloxacin in the free form. PEG-coated liposomal ciprofloxacin was well tolerated in relatively high doses, permitting once daily administration with relatively low ciprofloxacin clearance and without compromising therapeutic efficacy.

Animals↗

PubMed2001

Antisense GLUT-1 protects mesangial cells from glucose induction of GLUT-1 and fibronectin expression.

A stable clone of rat mesangial cells expressing antisense GLUT-1 (i.e., MCGT1AS cells) was developed to protect them from high glucose exposure. GLUT-1 protein was reduced 50%, and the 2-deoxy-[(3)H]glucose uptake rate was reduced 33% in MCGT1AS. MCLacZ control cells and MCGT1 GLUT-1-overexpressing cells were used for comparisons. In MCLacZ, 20 mM D-glucose increased GLUT-1 transcription 90% vs. no increase in MCGT1AS. Glucose (8 mM) and 12 mM xylitol [a hexose monophosphate (HMP) shunt substrate] did not stimulate GLUT-1 transcription. An 87% replacement of the standard 8 mM D-glucose with 3-O-methylglucose reduced GLUT-1 transcription 80%. D-Glucose (20 mM) increased fibronectin mRNA and protein by 47 and 100%, respectively, in MCLacZ vs. no increases in MCGT1AS. Fibronectin synthesis was elevated 48% in MCGT1 and reduced 44% in MCGT1AS. We conclude that 1) transcription of GLUT-1 in response to D-glucose depends on glucose metabolism, although not through the HMP shunt, and 2) antisense GLUT-1 treatment of mesangial cells blocks D-glucose-induced GLUT-1 and fibronectin expression, thereby demonstrating a protective effect that could be beneficial in the setting of diabetes.

ATP-Binding Cassette Transporters↗

PubMed2001

Molecular cloning and characterization of a novel human gene (HSPBAP1) from human fetal brain.

Rat PASS1 is a novel protein binding specifically to hsp27 and thus plays a role in regulating stress response in the living cell. Here we report on a human homologue of PASS1, encoded by the gene HSPBAP1. The gene was cloned and identified during a large-scale sequencing analysis of a human fetal brain cDNA library. The human protein shared 80% amino acid identity with rat PASS1. According to bioinformatics analysis, the HSPBAP1 gene is located on chromosome 3q21. RT-PCR analysis indicated that HSPBAP1 was abundant in thymus and pancreas but had a ubiquitously low expression pattern in other human adult tissues except for brain where it was absent.

Amino Acid Sequence↗

PubMed2001

[Cases-Control association study and transmission disequilibrium test of T102C polymorphism in 5HT2A and Tourette syndrome].

OBJECTIVE: To investigate whether T102C polymorphism in 5HT2A (serotonin receptor 2A) is associated with Tourette syndrome. METHODS: Both case-control association analysis and Transmission Disequilibrium Test(TDT), in addition to polymerase chain reaction and RFLP technique were used in 157 trios with Tourette syndrome (TS) and 120 controls. A semi-structured "Schedule for Tourette and other behavioral syndrome" was used in family history-collecting. Both the criteria of "Diagnostic and Statistical Manual of Mental Disorders"(DSM-IV) and that of Tourette syndrome association (TSA) were used in the diagnosis of Tourette syndrome and related disorders. RESULTS: The association between T102C polymorphism in 5HT2A and Tourette syndrome comorbided with obsessive compulsive disorder (OCD) was found by genotype-wise analysis (chi(2)=8.38,P=0.004) and allele-wise analysis (chi(2)=4.84,P=0.028), which was further confirmed by TDT analysis (chi(2)=5.12,P=0.02). No evidence of association or transmission disequilibrium between 102T/C polymorphism in 5HT2A and this disease in pure TS and total TS sample was found. CONCLUSION: 102T/C polymorphism in 5HT2A is exclusively associated with Tourette syndrome comorbided with DSM-IV OCD, which may constitute an independent subtype of Tourette syndrome.

Adolescent↗

PubMed2001

In vitro prevention of cell-mediated xeno-graft rejection via the Fas/FasL-pathway in CrmA-transducted porcine kidney cells.

Cell-mediated cytotoxicity may be involved in delayed and/or chronic xenograft rejection in which apoptosis is induced in the grafted cells via the Fas/Fas-ligand (FasL) and perforin/granzyme pathways. One barrier to the potential use of xeonogenic grafts for humans may be Fas/FasL-mediated apoptosis, which would be blocked by the gene expression of cytokine response modifier A (CrmA), a cowpox virus gene product. The purpose of this study is to explore whether crmA is an effective candidate gene for inhibiting apoptosis in an in vitro model of xenograft rejection, using Fas-expressing non-primate cells cultured with a soluble recombinant human FasL (sFasL). A recombinant adenovirus vector expressing CrmA (AxCALNLCrmA) was successfully generated with a Cre-mediated switching system. PK15 cells, derived from a porcine kidney and infected with AxCALNLCrmA and/or AxCANCre at a multiplicity of infection (MOI) ranging from 0.1 to 100, were cultured with human sFasL derived from KFL74.18, a human FasL-overexpressed cell line. The gene-expression level of the PK15 cells was confirmed by CrmA-immune staining. Approximately 70% of the control PK15 cells showed induced apoptosis when cultured with sFasL. In contrast, the apoptosis was dramatically reduced in crmA-gene-transduced PK15 cells. The inhibitory effect of apoptosis increased with an increase in the infection dose of AxCANCre. In addition, the activity of caspases 3 and 8 was significantly inhibited in the crmA-transduced cells. These results indicate that CrmA is an effective gene product for inhibiting Fas/FasL-mediated apoptosis, which suggests the potential therapeutic use of its gene transduction to protect against graft damage due to delayed and/or chronic xenograft rejection.

Animals↗

PubMed2001

[The sedimentation rate and fractional dimension during flocculation with modified natural polymer and polymeric aluminum chloride].

The sedimentation rate and fractional dimension of the floc was studied during the process of the organic waste water treatment with modified natural polymer (CMS) and polymeric aluminum chloride (PAC). Irregular garrulous form of the floc was observed with microscope and electron-scanning microscope. The results showed that the sedimentation rate was 2.6 mm/min with the modified natural polymer (CMS) and 1.7 mm/min without CMS in condition of keeping the pH value to 6.86 and added quantity of PAC to 80 mg/L. The fractional dimension of the floc Df was calculated to be 1.70 in the best sedimentation rate.

Aluminum Chloride↗

PubMed2001

[Corrosion and haemocompatibility of 316L stainless steel with electroplated Rh film].

In this study, surface modification by electroplating Rh on 316L stainless steel was carried out in order to improve the corrosion resistance and blood compatibility of implants. XPS was used to characterize the Rh film. The corrosion behavior of 316L stainless steel with electroplated Rh and non-treated was studied in Tyrode's biological solution. Additionally, the haemocompatibility of 316L stainless steel with electroplated Rh was evaluated by preliminary hemolysis test. The results showed that the corrosion resistance of 316L stainless steel with electroplated Rh was improved, and hemolysis decreased, which indicated that electroplating Rh can improve the blood compatibility of 316L stainless steel.

Animals↗

PubMed2001

Pharmacodynamic and pharmacokinetic characterization of poly(ethylene glycol) conjugation to met-enkephalin analog [D-Pen2, D-Pen5]-enkephalin (DPDPE).

Poly(ethylene glycol), or PEG, conjugation to proteins and peptides is a growing technology used to enhance efficacy of therapeutics. This investigation assesses pharmacodynamic and pharmacokinetic characteristics of PEG-conjugated [D-Pen2,D-Pen5]-enkephalin (DPDPE), a met-enkephalin analog, in rodent (in vivo, in situ) and bovine (in vitro) systems. PEG-DPDPE showed increased analgesia (i.v.) compared with nonconjugated form (p < 0.01), despite a 172-fold lower binding affinity for the delta-opioid receptor. [125I]PEG-DPDPE had a 36-fold greater hydrophilicity (p < 0.01) and 12% increase in the unbound plasma protein fraction (p < 0.01), compared with [(125)I]DPDPE. [125I]PEG-DPDPE had a 2.5-fold increase in elimination half-life (p < 0.01), 2.7-fold decrease in volume of distribution (p < 0.01), and a 7-fold decrease in plasma clearance rate (p < 0.01) to [125I]DPDPE. Time course distribution showed significant concentration differences (p < 0.01) in plasma, whole blood, liver, gallbladder, gastrointestinal (GI) content, GI tract, kidneys, spleen, urine, and brain (brain, p < 0.05), between the conjugated and nonconjugated forms. Increased brain uptake of [(125)I]PEG-DPDPE corresponded to analgesia data. [125I]PEG-DPDPE in brain was shown to be 58.9% intact, with 41.1% existing as [125I]DPDPE (metabolite), whereas [125I]DPDPE was 25.7% intact in the brain (at 30 min). In vitro P-glycoprotein affinity was shown for [125I]DPDPE (p < 0.01) but not shown for [125I]PEG-DPDPE. In vitro saturable uptake, with 100 microM DPDPE, was shown for [125I]PEG-DPDPE (p < 0.05). In this study, PEG-conjugated DPDPE seems to act as a prodrug, enhancing peripheral pharmacokinetics, while undergoing hydrolysis in the brain and allowing nonconjugated DPDPE to act at the receptor.

Analgesics, Opioid↗

PubMed2001

Oral health status of heroin users in a rehabilitation centre in Hubei province, China.

OBJECTIVE: To report on the oral health of heroin users and to determine risk factors for oral health status. DESIGN: All heroin users at one rehabilitation camp received an interview using a pre-tested questionnaire from one of three trained interviewers and a dental examination using World Health Organization recommended procedures from one of three calibrated dentists. SETTING: Interviews and examinations were carried out at Hubei Province camp. PARTICIPANTS: All 520 resident heroin users at the camp participated in the study. OUTCOME MEASURES: Oral hygiene expressed using the Debris Index; caries status by DMFT; periodontal status by percentage with bleeding, pocketing and calculus; mucosal status using standard World Health Organization criteria. RESULTS: One hundred (19%) of the heroin users were caries free; their mean DMFT was 4.2. The majority (92%) of the DMFT was decay and only a small proportion (8%) was treatment related. The proportion of heroin users with bleeding, calculus, shallow pocketing and deep pocketing was 42%, 95%, 42% and 8% respectively. The mean Debris Index score was 3.2. Mucosal lesions were present in 31 subjects (6%). Using multivariate analysis, duration of heroin use and education were risk factors for DMFT, route of drug administration was a risk factor for calculus and gender was a risk factor for deep pocketing. CONCLUSIONS: There are indications of poorer periodontal health as well as higher caries experience in this group when compared to provincial dental epidemiological data. Mucosal lesions were not widely prevalent. Both social factors and characteristics of drug use were related to oral health in this group.

Administration, Oral↗

PubMed2001

Selective repopulation of mice liver after Fas-resistant hepatocyte transplantation.

Hepatocyte transplantation has been proposed as a potential therapeutic method to treat irreversible liver failure and inherited hepatic disorders, although transplanted cells do not easily reconstruct the liver tissue under intact conditions. This study was aimed at modulating the recipient liver conditions to promote repopulation of the liver after hepatocyte transplantation. Hepatocytes isolated from male MRL-lpr/lpr (lpr) mice with a mutation of Fas antigen were transplanted in a number of 1 x 10(6) cells in female MRL-+/+ (wild-type mice) by intrasplenic injection. An agonistic anti-Fas antibody (0.15 mg/kg) was administered intravenously 24 h after cell transplantation. We also administrated the antibody at 0.3 mg/kg 1 week after grafting and at 0.6 mg/kg 2 weeks after transplantation. The liver specimens were taken at different time intervals for histological examination. The reconstructed male lpr hepatocytes in the female wild-type mice were determined by a real-time quantitative PCR assay using the primers and probe for the sry gene. The pathologic findings of the recipient livers after treatment with anti-Fas antibody revealed a large number of apoptotic hepatocytes. The grafted lpr hepatocytes were observed to reconstruct as much as 6.9% of the recipient liver in the anti-Fas antibody-treated group 3 months after transplantation. In contrast, we observed the transplanted cells at lower than 0.1% in the nontreated livers. These findings demonstrated that repeated induction of apoptosis in recipient hepatocytes shifts the environment of the liver to a regenerative condition. This method may be useful to promote the reconstruction of transplanted hepatocytes in a recipient liver.

Animals↗