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Biomedical subjects

K Zheng

Publications and source records attributed to K Zheng.

At least 19 recordsLinked to original sources
PubMed2005

The Biomolecular Interaction Network Database and related tools 2005 update.

The Biomolecular Interaction Network Database (BIND) (http://bind.ca) archives biomolecular interaction, reaction, complex and pathway information. Our aim is to curate the details about molecular interactions that arise from published experimental research and to provide this information, as well as tools to enable data analysis, freely to researchers worldwide. BIND data are curated into a comprehensive machine-readable archive of computable information and provides users with methods to discover interactions and molecular mechanisms. BIND has worked to develop new methods for visualization that amplify the underlying annotation of genes and proteins to facilitate the study of molecular interaction networks. BIND has maintained an open database policy since its inception in 1999. Data growth has proceeded at a tremendous rate, approaching over 100 000 records. New services provided include a new BIND Query and Submission interface, a Standard Object Access Protocol service and the Small Molecule Interaction Database (http://smid.blueprint.org) that allows users to determine probable small molecule binding sites of new sequences and examine conserved binding residues.

Animals↗
PubMed2004

Association between apolipoprotein CI HpaI polymorphism and sporadic Alzheimer's disease in Chinese.

OBJECTIVE: To investigate into the relationship of apolipoprotein CI (ApoCI) polymorphism with sporadic Alzheimer's disease (AD) in Chinese. SUBJECTS AND METHODS: A total of 257 AD patients and 242 age-matched elderly individuals were genotyped for the ApoCI HpaI and apolipoprotein E (ApoE) HhaI polymorphisms. RESULTS: The ApoCI A allele was associated with AD of moderate to severe dementia when patients were divided into two subgroups according to Clinical Dementia Rating scale, and the AA genotype was strongly associated with moderate to severe AD in ApoE epsilon4 allele carriers [odds ratio (OR) = 8.19, 95% confidential interval: 1.28-52.30, after adjusting for age and gender by logistic regression analysis], although in total no significant differences of allele or genotype frequency between patients and controls were found. CONCLUSION: The present study partially confirmed the previous findings, suggesting that the ApoCI A allele might contribute to the susceptibility to moderate to severe sporadic AD in Chinese.

Aged↗
PubMed2001

Rapid, efficient genotyping of clinical tumor samples by laser-capture microdissection/PCR/SSCP.

BACKGROUND: Mutation analysis is becoming increasingly important in clinical practice, since sporadic mutations in tumors often correlate with prognosis and/or therapeutic response. However, the labor-intensive nature of the molecular analyses has limited the routine clinical use of tumor genotyping. Laser-capture microdissection (LCM) allows procurement of relatively pure tumor cell populations. We have investigated the possibility that the use of laser-capture microdissection would allow elimination of time-consuming intermediate steps in tumor genotyping. Design. Archival formalin-fixed, paraffin-embedded tissues from seven cases of colorectal adenocarcinoma were laser- and hand-microdissected and subsequently evaluated by PCR/SSCP/sequencing for Ki-ras exon 1 and p53 exons 5, 7, and 8. Results. Mutations in Ki-ras exon 1 and/or p53 exons 5 and 7 were detected in five of the seven samples. In the hand-microdissected samples, confident identification of mutations was possible in several cases only after band excision, DNA elution, reamplification, and verification of mutant enrichment by a second SSCP analysis prior to sequencing. In the laser-microdissected samples, confident mutation identification was possible in all cases with direct sequencing of the original PCR product, reducing the time required for molecular analysis to 3 days. Conclusion. Using laser-capture microdissection, mutant signals are strong enough to sequence directly from original PCR products. With rapid, efficient genotyping by LCM/PCR/SSCP, results can be incorporated directly into the surgical pathology report.

Base Sequence↗
PubMed2001

Characterization of hyperplastic foci observed in surgical specimens of hepatocellular carcinoma.

By reviewing previous surgical specimens of hepatocellular carcinoma, 17 cases with hyperplastic foci (HPF) characterized by discernible increase in nuclear densities, could be histologically selected. Nuclear densities of HPF and control hepatic parenchyma were assessed quantitatively by counting the nuclear number of hepatic cells, and proliferating cell nuclear antigen labeling index was measured. HPF occurred multifocally, confined within a lobular unit, smoothly merging into surrounding hepatic parenchyma. Nuclear densities of HPF were 1.71 times greater than those of control hepatic parenchyma. The hepatocytes of HPF also showed significantly higher proliferative activities than those of control parenchyma. In addition, noticeable structural distortions, such as focal trabecular thickening or microacinar formation of hepatocytes, were sometimes observed in HPF. However, these HPF seemed to be distinguished from minute de novo hepatocellular carcinoma (HCC) or intrahepatic HCC metastasis, because of paucity of distinctive atypical changes, and intimate correlation with neighboring hepatocytes. Several adjacent HPF were aggregated to form a much larger unit of a hyperplastic area with loss of fibrous septa of liver cirrhosis. It was suggested that grossly detectable large regenerative nodules are produced via fusion of several adjacent HPF.

Adult↗
PubMed2001

Study on detecting antibodies to Toxoplasma gondii in pooled serum of blood donors by Dot-IGSS.

To prevent post-transfusion toxoplasmosis, the sera of blood donors, per six of which were mixed as a pool, were examined for anti-Toxoplasma gondii antibiodies by Dot-immunogold silver staining (Dot-IGSS) with the single serum specimens examined simultaneously. The results showed that the sensitivity and specificity of serum pool method were 92.31% and 99.96% respectively. The consistent rate between the two methods was 99.73% and kappa value was 0.947 (p<0.01). Considering the mean infection rate of Toxoplasma gondii being 4.86% in China, if the serum pool method be adoped, with pool size k=5, a 57% reduction in the number of tests, as well as the cost of the screen, can be expected. Beside the social benefit, consequent upon the interruption of the Toxoplasma gondii infection spread through blood transfusion also can be expected.

Animals↗
PubMed2001

[Application of corepraxia in the implantation of intraocular lens].

PURPOSE: In the cases of aphakia or cataract which complicated with iridosteresis, corectasis and pupil displacement, corepraxia was performed when implanting intraocular lens (IOL) in order to recover the normal shape and position of pupil, improve postoperative visual acuity and prevent monodiplopia and glare. METHODS: In the cases which have iridosteresis at the direction of 9-3 oclock or updrawn pupil, iris suture was performed at the incision directly(open method); while those at the direction of 3-9 o'clock, operation was performed outside the anterior chamber (close method). RESULTS: In 22 cases, the percentage which having visual acuity better than 0.5 is 65%, having nearly round shape pupil 67%, having pupil diameter less than 3 mm 73%, having normal pupil position 67%. CONCLUSION: All kinds of deformed pupil can be recovered to their normal shape, size and position by performing corepraxia while IOL was implanted. The prolene has light reaction and better effect in iris suture.

Adolescent↗
PubMed2000

Elucidation of peptide metabolism by on-line immunoaffinity liquid chromatography mass spectrometry.

An immunoaffinity chromatography extraction capillary liquid chromatography separation has been coupled to electrospray ionization mass spectrometry for on-line characterization of drug metabolites of a therapeutic peptide in plasma. It is demonstrated that the selectivity, sensitivity and molecular weight data provided by immunoaffinity chromatography coupled to liquid chromatography/mass spectrometry provides a means of rapidly achieving qualitative determinations of small amounts of material in complicated biological matrices such as plasma. The ability to detect the peptide in rat plasma at a level of 10 ng/mL is demonstrated using this method. In addition, experiments to study the epitope of the peptide by enzymatic digestion and mass spectrometry are also discussed. The method is proposed as an alternative approach to studying the metabolism of therapeutic peptides.

Amino Acid Sequence↗
PubMed2000

[Determination of chlorzoxazone and paracetamol in co-chlorzoxazone tablet by multi-wavelength linear regression method].

This paper reports that the contents of chlorzoxazone and paracetamol in the co-chlorzoxazone tablet may be determined by the multi-wavelength linear regression method. The program was edited by BASIC. The average recovery and RSD of chlorzoxazone and paracetamol were 98.67%, 0.34% and 100.05%, 0.31% (n = 5), respectively. This method is simple and rapid with satisfactory results.

Acetaminophen↗
PubMed1999

Absence of the alpha6(IV) chain of collagen type IV in Alport syndrome is related to a failure at the protein assembly level and does not result in diffuse leiomyomatosis.

X-linked Alport syndrome is a progressive nephropathy associated with mutations in the COL4A5 gene. The kidney usually lacks the alpha3-alpha6 chains of collagen type IV, although each is coded by a separate gene. The molecular basis for this loss remains unclear. In canine X-linked hereditary nephritis, a model for X-linked Alport syndrome, a COL4A5 mutation results in reduced mRNA levels for the alpha3, alpha4, and alpha5 chains in the kidney, implying a mechanism coordinating the production of these 3 chains. To examine whether production of alpha6 chain is under the same control, we studied smooth muscle cells from this animal model. We determined the canine COL4A5 and COL4A6 genes are separated by 435 bp, with two first exons for COL4A6 separated by 978 bp. These two regions are >/= 78% identical to the human sequences that have promoter activity. Despite this potential basis for coordinated transcription of the COL4A5 and COL4A6 genes, the alpha6 mRNA level remained normal in affected male dog smooth muscle while the alpha5 mRNA level was markedly reduced. However, both alpha5 and alpha6 chains were absent at the protein level. Our results suggest that production of the alpha6 chain is under a control mechanism separate from that coordinating the alpha3-alpha5 chains and that the lack of the alpha6 chain in Alport syndrome is related to a failure at the protein assembly level, raising the possibility that the alpha5 and alpha6 chains are present in the same network. The lack of the alpha6 chain does not obviously result in disease, in particular leiomyomatosis, as is seen in Alport patients with deletions involving the COL4A5 and COL4A6 genes.

Animals↗
PubMed1999

Contributions of CD4+, CD8+, and CD4+CD8+ T cells to skewing within the peripheral T cell receptor beta chain repertoire of healthy macaques.

Diversity in the peripheral T cell receptor repertoire of rhesus (Macaca mulatta) and pig-tailed macaques (Macaca nemestrina) has been studied by examining the profile of CDR3 lengths in TCR beta chains. Expressed CDR3 length distribution profiles for individual TCRBV families were obtained from total peripheral blood mononuclear cells (PBMC) and T cell subsets isolated from PBMC. These studies reveal that the T cell receptor repertoire of PBMC from healthy macaques often exhibits skewing in TCRBV family CDR3 profiles. The skewing of TCRBV family CDR3 profiles was evident as discrete expanded length(s) and was detected in up to 50% of the PBMC profiles. Analyses of separated T cell populations demonstrated that the CD8+ T cell subset was responsible for the majority of observed skewing in CDR3 length profiles. However, CD4+ T cells were also shown to contribute to the skewed peripheral PBMC repertoire in these animals. While certain TCRBV families frequently displayed skewed profiles, there was no concordance in the particular CDR3 lengths expanded among the different animals. Furthermore, an additional feature of the peripheral blood of the animals studied was the presence of an unusual population of extrathymic CD4 and CD8+ (double-positive) T cells (up to 9.6% in the PBMC of rhesus macaques). The double-positive T cells could be differentiated from CD4 single-positive and CD8 single-positive T cells by their increased surface expression of LFA-1 and decreased CD62L expression. The percentage of the double-positive T cells was higher in rhesus than pig-tailed macaques and contributed substantially to the peripheral T cell repertoire.

Animals↗
PubMed1999

Effect of dietary vitamin E supplementation on murine nasal allergy.

BACKGROUND: Although many studies have reported the effects of dietary vitamin E on the immune response, none so far has assessed its role in nasal allergy. METHODS: Female BALB/c mice were randomized into two groups and fed a 20% casein diet (control group, 50 mg vitamin E/kg diet) or this diet supplemented with 535 mg vitamin E/kg diet (vitamin E group, 585 mg vitamin E/kg diet) for 4 weeks. During the fifth week, the mice in each group were divided into two subgroups to form a total of four treatment groups: group A (control), group B [control + toluene diisocyanate (TDI) sensitization], group C (vitamin E supplementation), and group D (vitamin E supplementation + TDI sensitization). Groups B and D were treated with two courses of intranasal application of 5% TDI in ethyl acetate, whereas groups A and C were treated with ethyl acetate alone. A week after second sensitization all groups were provoked by applying 2.5% of TDI in the vehicle and nasal allergic responses were observed for 10 minutes. Splenic lymphoproliferation, splenic cell cytokines, and the total serum IgE were measured. RESULTS: Members of group D had lower (P < 0.01) scores of nasal response and sneezed less frequently (P < 0.01) than those of group B. Similarly, splenic lymphoproliferation and production of IL-4 and IL-5 as well as the total serum IgE levels were lower (P < 0.01) in group D than in group B. CONCLUSIONS: The results indicate that higher doses of vitamin E supplementation may suppress nasal allergic responses.

Allergens↗
PubMed1998

On-line analysis by capillary separations interfaced to an ion trap storage/reflectron time-of-flight mass spectrometer.

The interface of high-resolution capillary separation methods to time-of-flight mass spectrometry (TOF-MS) has generated considerable interest since TOF can provide the rapid and sensitive detection required by high resolution separations. In recent years, our laboratory has developed a variety of high-resolution capillary separation methods interfaced to TOF-MS via an ion trap storage/reflectron time-of-flight (IT/reTOF) instrument. Using this hybrid configuration, detection of fast separations at very low detection levels has been successfully performed for on-line separations of peptides and protein digests using electrospray ionization. In this report, we review the current status in our laboratory of interfacing high-performance liquid chromatography, capillary electrophoresis, and capillary electrochromatography to an IT/reTOF-MS instrument and various applications that have been developed involving this technology.

Chromatography, High Pressure Liquid↗
PubMed1998

Role of distinct type IV collagen networks in glomerular development and function.

BACKGROUND: In X-linked Alport syndrome, mutations in the COL4A5 gene encoding the alpha 5 chain of type IV collagen result in progressive renal failure. This nephropathy appears to relate to the arrest of a switch from an alpha 1/alpha 2 to an alpha 3/alpha 4/alpha 5 network of type IV collagen in the developing glomerular basement membrane (GBM; Kalluri et al, J Clin Invest 99:2470, 1997). METHODS: We examined the role of this switch in glomerular development and function using a canine model of X-linked nephritis with a COL4A5 mutation. The electron microscopic appearance and the expression of the alpha 1-alpha 6 chains of type IV collagen in the GBM was correlated with glomerular function. RESULTS: In normal neonatal glomeruli, once capillary loops were present, there was staining of GBM for the alpha 1-alpha 5 chains. Prior to this stage, only alpha 1 and alpha 2 chains were present, with rare glomeruli positive for the alpha 5 chain. As glomeruli matured, the alpha 1 and alpha 2 chains tended to disappear from the GBM, with the alpha 3-alpha 5 chains remaining. In affected male dogs, only the alpha 1 and alpha 2 chains were detected at any stage. GBM ultrastructure in these dogs remained normal until one month and proteinuria did not appear until two months. CONCLUSION: Our results show that normal glomerular development involves a switch in type IV collagen networks. In affected male dogs, a failure of this switch results in an absence of the alpha 3/alpha 4/alpha 5 network and a persistence of the alpha 1/alpha 2 network in GBM. GBM ultrastructure and glomerular function remain normal for one month, indicating that GBM deterioration in Alport syndrome begins as a postnatal process. Hence, only the alpha 1/alpha 2 network is essential for normal glomerular development, whereas the alpha 3/alpha 4/alpha 5 network is essential for long-term maintenance of glomerular structure and function.

Aging↗
PubMed1998

[Chemical constituents of Conyza blinii Lévl].

Five compounds were isolated from the aerial part of Conyza blinii. On the basis of physicochemical properties and spectroscopic analysis, they were identified as alpha-spinasterol, 5, 8-dihydroxy-7, 3', 4'-trimethoxyflavone, caffeic acid, quercetin and syringic acid. All these compounds were isolated from the plant of C. blinii for the first time.

Asteraceae↗