Biomedical subjects

Hui Zhou

Publications and source records attributed to Hui Zhou.

At least 91 records · Page 5Linked to original sources

PubMed2004

Enantioselective cyanosilylation of ketones by a catalytic double-activation method with an aluminium complex and an N-oxide.

Double-activation catalysis promises high catalytic efficiency in the enantioselective cyanosilylation of ketones through the combined use of a Lewis acid and a Lewis base. Catalyst systems composed of a chiral salen-Al complex and an N-oxide have high catalytic turnovers (200 for aromatic ketones, 1000 for aliphatic ones). With these catalysts, a wide range of aliphatic and aromatic ketones were converted under mild conditions into tertiary cyanohydrin O-TMS ethers in excellent yields and with high enantioselectivities (94% ee for aromatic ketones, 90% ee for aliphatic ones). Preliminary mechanistic studies revealed that the salen-Al complex played the role of a Lewis acid to activate the ketone and the N-oxide that of a Lewis base to activate TMSCN; that is, double activation.

Journal Article↗

PubMed2004

c-KIT codon 816 mutation in a recurrent and metastatic dysgerminoma of a 14-year-old girl: case study.

Dysgerminomas are rare female germ-cell tumors that correspond histologically and immunohistochemically to seminomas. Analogous to seminomas, most dysgerminomas respond very well to cisplatin- or carboplatin-based chemotherapy and to radiotherapy. KIT tyrosine kinase is crucial for normal germ-cell development, and its expression is observed in the majority of seminomas and dysgerminomas. Recently, activating KIT mutations were described in a panel of male germ-cell tumors [5, 10]. All mutations were localized in exon 17, encoding the second tyrosine kinase domain. Because receptor tyrosine kinase KIT might also be involved in the pathogenesis of dysgerminomas, we studied the expression and mutational status of a pure dysgerminoma, which was sent to our department for diagnostic reasons. The tumor revealed an exon 17 D816 V mutation in the c-KIT gene and strong KIT expression was found immunohistochemically. Clinically, the tumor was highly aggressive and resistant to carboplatin-based chemotherapy. Our case raises the question of whether exon 17 c-KIT mutations might be involved in the pathogenesis of dysgerminoma and whether exon 17 KIT mutations may predict aggressive and chemotherapy-resistant behavior of dysgerminomas.

Adolescent↗

PubMed2004

Different expression strategy: multiple intronic gene clusters of box H/ACA snoRNA in Drosophila melanogaster.

The high degree of rRNA pseudouridylation in Drosophila melanogaster provides a good model for studying the genomic organization, structural and functional diversity of box H/ACA small nucleolar RNAs (snoRNAs). Accounting for both conserved sequence motifs and secondary structures, we have developed a computer-assisted method for box H/ACA snoRNA searching. Ten snoRNA clusters containing 42 box H/ACA snoRNAs were identified from D.melanogaster. Strikingly, they are located in the introns of eight protein-coding genes. In contrast to the mode of one snoRNA per intron so far observed in all animals, our results demonstrate for the first time a novel polycistronic organization that implies a different expression strategy for a box H/ACA snoRNA gene when compared to box C/D snoRNAs in D.melanogaster. Mutiple isoforms of the box H/ACA snoRNAs, from which most clusters are made up, were observed in D.melanogaster. The degree of sequence similarity between the isoforms varies from 99% to 70%, implying duplication events in different periods and a trend of enlarging the intronic snoRNA clusters. The variation in the functional elements of the isoforms could lead to partial alternation of snoRNA's function in loss or gain of rRNA complementary sequences and probably contributes to the great diversity of rRNA pseudouridylation in D.melanogaster.

Animals↗

PubMed2004

Preparative counter-current chromatography isolation of liensinine and its analogues from embryo of the seed of Nelumbo nucifera GAERTN. using upright coil planet centrifuge with four multilayer coils connected in series.

Preparative counter-current chromatography (CCC) isolation of liensinine and its analogues, isoliensinine and neferine from embryo of the seed of Nelumbo nucifera GAERTN. has been successfully performed for the first time using upright coil planet centrifuge with four multilayer coils connected in series with 1600 mL capacity. Two kinds of two-phase solvent systems were applied to preparative CCC isolation. The first was the system composed of light petroleum (b.p. 60-90 degrees C)-ethyl acetate-tetrachloromethane-chloroform-methanol-water (1:1:4:4:6:2, v/v) which was very suitable for fast and small-scale CCC isolation. The second was the system composed of ethyl acetate-tetrachloromethane-methanol-water (1:6:4:1, v/v), which was the optimum for large-scale CCC isolation. Using the first system, 1102 mg of the crude alkaloid was purified in one-step separation of 150 min, yielding 350 mg neferine, 100 mg isoliensinine and 95 mg liensinine with over 95% purity. While using the second solvent system, 5850 mg of the crude alkaloid was purified in one-step separation of 9 h, yielding 2545 mg neferine, 698 mg isoliensinine and 650 mg liensinine with over 97% purity. Structures of the compounds were identified by electrospray ionization multiple mass spectrometry, one- and two-dimensional NMR.

Countercurrent Distribution↗

PubMed2004

Sulphur by-product: the relationship between volatile sulphur compounds and dental plaque-induced gingivitis.

The purpose of this study was to evaluate the relationship between volatile sulphur compounds (VSC) and gingival health status, and to monitor the changes in VSC in early dental plaque-induced gingivitis. Using an experimental gingivitis model, twelve subjects between 19 and 28 years old, with a healthy gingival status, refrained from brushing and flossing one randomly selected half of the mandibular arch for two weeks. At baseline and during six subsequent appointments, gingival inflammation (GI), bleeding on probing (BOP), and sulfide levels (SUL) were measured using the Gingival Index and the Diamond Probe/Perio 2000 System. The Spearman correlation was used to compare the relationships between SUL, GI, and BOP on the brushing (B) and non-brushing (NB) sides. Data on the NB side revealed a stronger correlation than on the B side. Wilcoxon rank sum was used to evaluate the differences between mean SUL, GI, and BOP scores on the B and NB sides over time. Results indicate that SUL were the first periodontal parameter to show a significant difference between sides. SUL were significantly higher on the NB side at 4 of the 6 data collection intervals; therefore, SUL may be associated with the initiation and progression of early plaque-induced gingivitis.

Adult↗

PubMed2004

Identification of 20 microRNAs from Oryza sativa.

MicroRNAs (miRNAs) are present in both plant and animal kingdoms and represents a growing family of non-coding RNAs. These tiny RNAs act as small guides and direct negative regulations usually in the process of development through sequence complementarity to target mRNAs. Although a large number of miRNAs have been identified from various animals, so far plant miRNA studies have focused mainly on Arabidopsis. Here we describe the identification of 20 miRNAs from a rice cDNA library. All the miRNAs were presumably processed from precursors with stem-loop structures and were positively detected in rice cells from at least one tissue, some of which showed tissue-specific expression. Twenty-three unique rice genes were identified to be feasible targets for seven rice miRNAs, including four members of Scarecrow-like transcription factor, the targets of miR-39 that had been characterized in Arabidopsis. Lacking long complementarity, the regulatory targets of 13 miRNAs remain to be further investigated. A possible mechanism of translational repressor for plant miRNAs that lack perfect complementarity to target mRNAs is discussed.

Base Sequence↗

PubMed2004

Identification of a novel box C/D snoRNA from mouse nucleolar cDNA library.

By construction and screen of mouse nucleolar cDNA library, a novel mammalian small nucleolar RNAs (snoRNA) was identified. The novel snoRNA, 70 nt in length, displays structural features typical of C/D box snoRNA family. The snoRNA possesses an 11-nt-long rRNA antisense element and is predicted to guide the 2'-O-methylation of mouse 28S rRNA at G4043, a site unknown so far to be modified in vertebrates. The comparison of functional element of snoRNA guides among eukaryotes reveals that the novel snoRNA is a mammalian counterpart of yeast snR38 despite highly divergent sequence between them. Mouse and human snR38 and other cognates in distant vertebrates were positively detected with slight length variability. As expected, the rRNA ribose-methylation site predicted by mouse snR38 was precisely mapped by specific-primer extension assay. Furthermore, our analyses show that mouse and human snR38 gene have multiple variants and are nested in the introns of different host genes with unknown function. Thus, snR38 is a phylogenetically conserved methylation guide but exhibits different genomic organization in eukaryotes.

Animals↗

PubMed2004

Microtubule-associated serine/threonine kinase-205 kDa and Fc gamma receptor control IL-12 p40 synthesis and NF-kappa B activation.

Stimulation of murine macrophages with LPS results in the coordinated activation of a set of proinflammatory cytokines and costimulatory molecules, including TNF-alpha, IL-6, IL-1, IL-8, IL-12, and CD80. Macrophage LPS-induced synthesis of IL-12 is inhibited following FcgammaR ligation; TNF-alpha secretion is unchanged. We report that microtubule-associated serine/threonine kinase-205 kDa (MAST205) is required for LPS-induced IL-12 synthesis. RNA interference-mediated suppression of MAST205 results in the inhibition of LPS-stimulated IL-12 promoter activity and IL-12 secretion, from both J774 cells and bone marrow-derived macrophages. Similarly, dominant-negative MAST205 mutants inhibit LPS-stimulated IL-12 synthesis and NF-kappaB activation, but do not affect IL-1 or TNF-alpha signaling. Finally, macrophage FcgammaR ligation regulates MAST205 by inducing the rapid ubiquitination and proteasomal degradation of the protein.

Animals↗

PubMed2004

Genetic variation of Cordyceps sinensis, a fruit-body-producing entomopathogenic species from different geographical regions in China.

Cordyceps sinensis is one of the most valuable medicinal fungi in the Orient. It is naturally distributed in the eastern extension area of the Qinghai-Tibet plateau, at an altitude over 4000 m high. In order to investigate genetic variation and evolutionary relationships of C. sinensis from different geographical regions, 17 isolates of C. sinensis were collected from different provinces and the complete sequences of rDNA ITS were determined. On the basis of 5.8S rDNA and ITS region analysis, it was clearly shown that the ITS sequences within C. sinensis are highly homologous regardless of geographical origin. The distance values between the sequences in this study were lower than 0.03. This implied that C. sinensis from different geographic regions are the same species; they are not different species or a species complex. The results also showed that distance values between C. sinensis and Hirsutella sinensis are of the same order as those within C. sinensis from different geographic regions. This confirmed our previous results that C. sinensis should only have H. sinensis as its asexual stage whatever the geographic region from which the samples were collected. An rDNA ITS clone library was established to obtain further evidence for the interpretation of the fungal community structure from C. sinensis and to confirm the accuracy of the taxonomic identities produced by directly sequencing the rDNA ITS region. The discrimination between intraspecies of C. sinensis might provide additional data for the authentication of medicinal material at the species or intraspecies level.

Animals↗

PubMed2004

Pathogenesis of carcinoma of the papilla of Vater.

Most adenomas and carcinomas of the small intestine and extrahepatic bile ducts arise in the region of the papilla of Vater. In familial adenomatous polyposis (FAP) it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis at an early tumor stage. In about 80%, curative intended resection is possible. Operability is the most relevant prognostic factor. Most ampullary carcinomas resp. carcinomas of the papilla of Vater develop from adenomatous or flat dysplastic precursor lesions. They can be sited in the ampulloduodenal part of the papilla of Vater, which is lined by intestinal mucosa. They also can develop in deeper parts of the ampulla, which are lined by pancreaticobiliary duct mucosa. Intestinal-type adenocarcinoma and pancreaticobiliary-type adenocarcinoma represent the main histological types of ampullary carcinoma. Furthermore, there exist unusual types and undifferentiated carcinomas. Many carcinomas of intestinal type express the immunohistochemical marker profile of intestinal mucosa (keratin 7-, keratin 20+, MUC2+). Carcinomas of pancreaticobiliary type usually show the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20-, MUC2-). Even poorly differentiated carcinomas, as well as unusual histological types, may conserve the marker profile of the mucosa they developed from. These findings underline the concept of histogenetically different carcinomas of the papilla of Vater which develop either from intestinal- or from pancreaticobiliary-type mucosa of the papilla of Vater. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear at different frequencies. In future studies, molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. Consequently, the histologic classification should reflect the histogenesis of ampullary tumors from the two different types of papillary mucosa.

Adenocarcinoma↗

PubMed2004

Chronic hypoxia inhibits contraction of fetal arteries by increased endothelium-derived nitric oxide and prostaglandin synthesis.

OBJECTIVE: Chronic hypoxia causes redistribution of fetal cardiac output by mechanisms poorly understood. We tested the hypothesis that chronic hypoxia alters vascular reactivity of arteries from near-term fetal guinea pigs. METHODS: Pregnant guinea pigs (50 days, term = 65 days) were exposed to either normoxia (room air) or hypoxia (12% O2) for 14 days. Carotid artery ring segments from anesthetized fetuses were mounted onto myographs for measurement of force. Contractile responses to cumulative addition of prostaglandin F2alpha (PGF2alpha, 10(-9) M to 10(-5) M), U46619, a thromboxane mimetic (10(-12) M to 12(-6) M), and KCl (10 to 120 mM) were measured in the presence and absence of INDO (INDO, 10(-5) M) alone and INDO plus nitro-L-arginine (LNA, 10(-4) M), or INDO plus N6-iminoethyl-L-lysine (LNIL, 5 x 10(-5) M, a selective iNOS inhibitor), and measured in endothelium-intact and denuded arteries. Nitric oxide synthase (NOS) activity was measured in isolated arteries by 14C-L-arginine to 14C-L-citrulline conversion. RESULTS: Hypoxia decreased contractile responses to both PGF2alpha and U46619 under control conditions. Maximal contraction to both agonists was increased in hypoxemic arteries after INDO alone and INDO + LNA compared to normoxic controls. Endothelium-denudation abolished the differences between the groups. KCl contraction was unaffected by hypoxia. LNIL potentiated maximal PGF(2alpha) contraction but was similar between groups. Hypoxia increased (P < .05) total and Ca(2+)-dependent NOS activities by 1.7- and 2.1-fold, respectively, but had no effect on Ca(2+)-independent activity. CONCLUSION: Chronic hypoxia alters vascular reactivity of fetal carotid arteries by increasing the contribution of both vasodilator prostaglandins and nitric oxide and suggests that changes in local vascular mechanisms may be altered by chronic hypoxia.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed2004

New eremophilane-type sesquiterpenes from Ligularia lapathifolia.

Seven new eremophilanolides were isolated from the roots and rhizomes of Ligularia lapathifolia. Their structures were established as 3beta-angeloyloxy-8beta H-eremophil-7(11)-ene-12,8alpha (14beta, 6alpha)-diolide, 3beta-angeloyloxy-8beta-hydroxyeremophil-7(11)-ene-12,8alpha(14beta,6alpha)-diolide,3beta-angeloyloxy-8beta-methoxyeremophil- 7(11)-ene-12,8alpha(14beta,6alpha)-diolide,3beta-angeloyloxy-8beta-ethoxyeremophil-7(11)-ene-12, 8alpha (14beta,6alpha)-diolide, 3beta-angeloyloxy-10beta- hydroxyeremophil-8(9),7(11)-diene-12,8(14beta,6alpha)-diolide, 3beta-angeloyloxy-8,12-expoy-12alpha-hydroxy-8beta-methoxyeremophil-7(11)-en-14beta,6alpha-olide and 3beta-angeloyloxyeremophilan-7,11-dien-14beta,6alpha-olide, by means of spectroscopic analyses. Moreover, application of a photooxygenation reaction on 7 resulted in the generation of 2 with an alpha,beta-unsaturated gamma-lactone moiety. This biomimetic transformation supports a biogenetic pathway proposed for 2.

Asteraceae↗

PubMed2004

Serratane-type triterpenoids from Huperzia serrata.

Sixteen serratane-type triterpenoids including three new compounds, 14beta,15beta-epoxyserratan-3beta,21beta,29-triol (1), serrat-14-en-3beta,21beta,29-triol (2) and serrat-14-en-3alpha,21beta,24,29-tetraol (3), were isolated from the whole plant of Huperzia serrata (Thunb) Trev. The structures of these new compounds (1-3) were elucidated on the basis of spectral analysis.

Humans↗

PubMed2004

Carcinoma of the ampulla of Vater: comparative histologic/immunohistochemical classification and follow-up.

A broad histomorphologic spectrum of ampullary carcinomas of Vater make a reproducible histologic classification difficult. Using cytokeratin immunohistochemistry, we present a new classification of ampullary carcinomas and analyze their clinical significance. Fifty-five invasive carcinomas of Vater's ampulla were histologically classified into pancreaticobiliary, intestinal, and other types. Serial sections of all carcinoma specimens were additionally stained with antibodies to cytokeratins (CK7, CK20), apomucins (MUC1, MUC2, MUC5AC), CEA, CA19-9, Ki67, and p53. Follow-up of patients from 4 months to 22 years after surgery (mean interval, 51.6 months) was evaluated. Most carcinomas of the ampulla of Vater were of immunohistochemically pancreaticobiliary type (iPT, CK7+, CK20-; 54.5%) or intestinal type (immunohistochemically intestinal type [iIT], CK7-, CK20+; 23.6%). Some carcinomas of immunohistochemically "other" type (iOT both CK7+ and CK20+ or CK7- and CK20-; 21.8%) had precursor lesions of iIT or iPT. Carcinomas positive for MUC2 or CEA were associated with iIT (MUC2, P < 0.001; CEA, P = 0.003), whereas MUC5AC-positive carcinomas were related to iPT (P = 0.005). Our classification based on cytokeratin-immunohistochemistry correlated well with the histologic classification according to published criteria (kappa-coefficient = 0.398; P < 0.001). Furthermore, histologically unusual types could be histogenetically related to pancreaticobiliary duct mucosa or intestinal mucosa. Therefore, all 4 signet-ring cell carcinomas were iIT carcinomas. Thus, cytokeratin immunohistochemistry allows a reproducible, histogenetically based categorization of ampullary carcinomas. However, neither histopathologic nor immunohistochemical subgroups significantly correlated with clinical outcome in our German collective. The overall survival was significantly shorter in males (P = 0.032) and patients with positive nodal stage (N1 < N0; P = 0.0025).

Aged↗

PubMed2004

Identification of a novel variant CYP2C9 allele in Chinese.

OBJECTIVES: Cytochrome P450 (CYP) 2C9 metabolizes about 16% of drugs in current clinical use, including lornoxicam and tolbutamide. SNPs in the CYP2C9 gene have increasingly been recognized as determinants of the metabolic phenotype that underlies interindividual and ethnic differences. METHODS: The present study focused on a Chinese poor metabolizer (PM) whose apparent genotype (CYP2C9*1/CYP2C9*3) did not agree with his PM phenotype for both lornoxicam and tolbutamide. By sequencing his CYP2C9 gene, we identified a new variant CYP2C9 allele involving a T269C transversion in exon 2 that leads to a Leu90Pro substitution in the encoded protein. RESULTS: The CYP2C9 genotype analysis in the family of the poor metabolizer showed the new exon 2 change and CYP2C9*3 occurred on different alleles. Thus, the PM status of this subject could be attributed to his being heterozygous for the CYP2C9 T269C allele together with the CYP2C9*3. Frequency analysis in 147 unrelated Chinese males indicated approximately 2% of the Chinese population carry the allele. CONCLUSION: This study suggests that this novel CYP2C9 allele was correlated with reduced plasma clearance of drugs that are substrates for CYP2C9.

3' Untranslated Regions↗

PubMed2004

[Pathological changes and apoptosis of brain cells in rat embryo suffering from intrauterine hypoxia-ischemic injury].

OBJECTIVE: To observe the pathological changes of fetal rat brain cells caused by transient intrauterine ischemia in pregnant rats. METHODS: The uterine arteries of the pregnant rats at 17 days of gestation were clamped for 30 min in the experimental group, the samples were collected 24, 48 and 72 hours respectively after the clamping of artery, respectively. In control group, the pregnant rat's abdomens were cut open and closed but the uterine arteries were kept intact; the samples were collected 24, 48 and 72 hours after the sham operation, respectively. The pathological changes of brain tissues were observed under light microscope by HE, Nissl, cholinesterase staining, sequential TUNEL technique, and by electron microscopy as well. RESULTS: The edema, degeneration of neural cells and the hemorrhage of brain were observed in experimental group. The Nissl bodies and the activity of cholinesterase decreased. The apoptosis cells appeared 24 hours after hypoxia-ischemia injury and increased progressively with time. CONCLUSION: Uterine hypoxia and ischemia can cause severe damage to neural cells of fetal rat.

Animals↗

PubMed2004

[Effect of heart benefiting recipe in controlling IL-1beta, IL-6 and APPmRNA expression in brain of beta-amyloid protein induced rat model of dementia].

OBJECTIVE: To investigate the neuro-immune regulatory mechanism of Heart Benefiting recipe (HBR), an effective recipe for treatment of Alzheimer's disease (AD). METHODS: Using immunohistochemical and RT-PCR methods, the neuro-immunological pathological changes in the AD rat model induced by beta-amyloid protein (A beta1-40) via lateral cerebral ventricle injection, including mainly the glial fibrillary acidic protein expression and inflammatory cytokines IL-1beta, IL-6mRNA and beta-amyloid protein precursor (APPmRNA) gene expression were studied. And the effects of HBR on these parameters were observed. RESULTS: Deposition of A beta in cerebral tissue could induce activation of stellate glial cells and abnormal increased levels of inflammatory cytokines (IL-1beta and IL-6mRNA), also the elevation of APPmRNA level. HBR could effectively control the above-mentioned pathological changes. CONCLUSION: HBR could effectively control the inflammation and the A beta immune cascade reaction in brain of AD patients, it is one of the important therapeutic mechanisms of the recipe.

Alzheimer Disease↗

PubMed2004

[Factors of influence on quality evaluation of adhesive property on cataplasma].

OBJECTIVE: To provide experimental proof for establishing a standard quality evaluation method of adhesive property on Cataplasma by studying the factors of effect on evaluation of adhesive quality on Cataplasma. METHOD: With 180 degrees peel off test, tensile shear and adhesive force test, the influence caused by the square of samples, texture of fabric base and the moisture loss was tested with multifunctional material tester and first stickiness tester. RESULT: The peel off strength of 40 mm wide sample is 26% lower than that of the 20 mm wide sample (P < 0.05), and tensile shear strength had no significant difference. The peel off strength of transverse fabric base was higher than that of lengthways fabric base (P < 0.01). The tensile shear strength of transverse fabric base was lower than that of lengthways fabric base (P < 0.05). The sample with 35% moisture lost had a maximum tensile shear strength and the sample which lost 30% moisture lost had a maximum peel off strength; The sample which lost 20% moisture lost had a maximum first adhesive force. CONCLUSION: The square of samples, the texture of fabric base and the moisture loss of samples can all affect the evaluation of adhesive quality on Cataplasma.

Adhesiveness↗