Biomedical subjects

Dan Zhou

Publications and source records attributed to Dan Zhou.

28 records · Page 2Linked to original sources

PubMed2004

[Study on anti-HPV activity of Asarum heterotropoides].

OBJECTIVE: To screen anti-HPV effective fraction from Asarum heterotropoides. METHODS: Asarum heterotropoides was extracted with systematic solvents (petroleum benzine, ether, ethyl acetate, n-butanol, ethanol and distilled water) accordingly. The Polymerase Chain Reaction (FQ-PCR) was applied in the vitro pharmacodynamics for the extracts from Asarum heterotropoides. The amplification of HPV-DNA in the lesions of the isolated Condyloma acuminatum. RESULTS: After the water extracts of Asarum heterotropoides was used for HPV-DNA, the PCR amplification showed negative, with the minimum effective concentration 0.4 g/ml. But the other solvents extracts from Asarum heterotropoides appeared positive. CONCLUSION: The water extracts from Asarum heterotropoides are effective on anti-Human papillomavirus.

Antiviral Agents↗

PubMed2003

Chronic MCH-1 receptor modulation alters appetite, body weight and adiposity in rats.

Central administration of the neuropeptide melanin-concentrating hormone (MCH) stimulates feeding in rodents. We studied the effects of intracerebroventricular (i.c.v.) administration of an MCH-1 receptor agonist (Compound A) and an MCH-1 receptor antagonist (Compound B) on feeding in satiated rats. Compound B (10 microg, i.c.v.) blocked the acute orexigenic effect of Compound A (5 microg, i.c.v.). In an experiment designed to either stimulate or inhibit MCH-1 receptor signaling over an extended period, rats received continuous i.c.v. infusions of vehicle (saline), Compound A (30 microg/day), Compound B (30 or 48 microg/day) or neuropeptide Y (24 microg/day, as positive control) via implantable infusion pumps. Continuous MCH-1 receptor activation recapitulated the obese phenotype of MCH-over-expressor mice, manifest as enhanced feeding (+23%, P<0.001), caloric efficiency and body weight gain (+38%, P<0.005) over the 14-day period relative to controls. Chronic MCH-1 receptor activation also elevated plasma insulin and leptin levels significantly. Conversely, continuous MCH-1 receptor antagonism led to sustained reductions in food intake (-16%, P<0.001), body weight gain (-35%, P<0.01), and body fat gain relative to controls, without an effect on lean mass. Antagonism of the MCH-1 receptor may be an effective approach for the treatment of obesity.

Adipose Tissue↗

PubMed2003

[Pit pattern and endoscopic mucosal resection in diagnosis and treatment of colorectal tumors].

OBJECTIVE: To explore the effective methods to diagnose and treat colorectal cancer in its early stage. METHODS: 1 205 patients were examined by colonoscopy and mucosa staining with indigocarmine. The pit patterns were observed with magnifying endoscope and stereomicroscope according to the Kudo classification. The pathological diagnoses of the lesions were compared with their pit patterns. Electrocoagulation resection was performed on the prominent lesions and endoscopic mucosal resection (EMR) or endoscopic partial mucosal resection (EPMR) was performed on the flat lesions. RESULTS: In the 282 patients 478 prominent and flat lesions were found. There were 16 cases of laterally spreading tumor (LST), including I case of pit pattern II, 6 of pit pattern IIIL, 8 of pit pattern IV, and 1 of pit pattern Va, with 2 cases of intramembrane cancer and 1 case of IIa + IIc lesions invading the superficial myometrium among them. EMR and EPMR were performed on 14 LST lesions, 22 IIa lesions, and 14 IIb lesions. CONCLUSION: The examination of pit pattern is very important in early diagnosis of colorectal cancer and differentiation tumorous from non-tumorous lesions. V type pit pattern is an indicator of colorectal cancer. EMR and EPMR are safe and effective for flat lesions.

Colonoscopy↗

PubMed2002

CB1 cannabinoid receptor-mediated tyrosine phosphorylation of focal adhesion kinase-related non-kinase.

The effect of cannabinoid on the tyrosine phosphorylation of focal adhesion kinase (FAK) and focal adhesion kinase-related non-kinase (FRNK) was investigated in differentiated mouse neuroblastoma N1E-115 cells. HU-210, a potent cannabinoid agonist, elicited a time-dependent enhancement of tyrosine phosphorylation of FRNK, but not FAK. Pretreatment of cells with antisense oligodeoxynucleotide targeting CB1 cannabinoid receptor abolished HU-210-induced FRNK tyrosine phosphorylation. In addition, pretreatment of cells with 8-Br-cAMP also blocked HU-210-induced FRNK tyrosine phosphorylation. These data demonstrated that HU-210 induces FRNK tyrosine phosphorylation by activating G(i)-coupled CB1 cannabinoid receptor in N1E-115 cells. This newly discovered, cannabinoid-induced FRNK tyrosine phosphorylation might be a novel mechanism for cannabinoid-induced functional changes.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2002

Cloning, expression, secondary structure characterization of HMG box 1 of hUBF from E. coli and its binding to DNA.

Human upstream binding factor (hUBF) belonging to a family of protein containing DNA binding domain-HMG box, is important in the activation of rRNA gene transcription. It contains six tandemly arranged HMG box domains, each of which is thought to be as a basic architectural unit in the interaction of DNA and protein. Here the DNA binding domain of hUBF HMG box 1 was cloned and heterologously expressed in Escherichia coli. Through a single purification step using a Ni2+-chelating column, the highly purified recombinant protein could be obtained. This recombinant protein contains 99 amino acids with a hexahistidine tag added to the C-terminus. It was expressed as a monomer, which was determined by gel filtration. Circular dischroism studies show that it comprises approximately 54.3% alpha-helix and 43.6% random coil at pH 7. This result is in good agreement with that of FTIR, which are 59.9% alpha-helix and 40.1% random coil. There is no obvious change for the secondary structure of the recombinant protein as increasing pH from 5.0 to 12.0. But denaturation occurs at pH 3.0. Like many HMG box domains that were found in other proteins, it could bind to four-way DNA junction, a putative intermediate in DNA recombination, in a structure-specific manner. Magnesium ion has no effect on this binding activity, which is determined by both gel mobility shift assays and surface plasmon resonance (SPR). Since Mg2+ is present in the nucleus and RNA polymerase I is Mg2+-stimulated, we believe that this property is relevant for hUBF in vivo. SPR research shows that the recombinant hUBF HMG box 1 also has a strong binding ability to a GC-rich fragment within the rRNA gene core promoter.

Base Sequence↗

PubMed2002

[Comparison of curative effect for colon flat lesion between mucosa resection and fulguration with high frequency current after mucosa staining under magnifying endoscope].

OBJECTIVE: To observe the relationship between the pit patterns and pathology and compare the curative effect for colon flat lesion between endoscopic mucosa resection (EMR) and fulguration with high frequency current (FHFC). METHODS: They were divided to two groups. There were 37 cases for FHFC in group A, and 34 cases for EMR in Group B. The two groups were comparabal. Examining patients suffering with colon flat lesions with magnifying endoscope and observing the pit patterns of mucosa after staining with indicarmine. RESULTS: The pit patterns of inflammatory or hyperplastic lesions were mainly pit II, adenoma pit III and pit IV, and carcinomatous lesions pit IV and pit V. The worse the differentiation degree of lesions was, the higher the pit patterns were. There were no difference (P > 0.05) between group A and B in complication and quantity, classification and distribution of lesions. No canceration was detected in 21 cases with adenoma in group A, while 4 cases of canceration (all were adenocacinoma) was found in 20 cases whith adenoma in group B. There was significance in canceration between two groups (P < 0.05). CONCLUSIONS: The worse the differentiation degree of lesions was, the higher pit patterns were. EMR and FHFC share the same validity and security when treating the flat lesions, but by EMR, doctors could judge whether the lesions were resected completely, once the remained lesions were found, they could be resected immediately again lesion in case of omission of canceration.

Adult↗

PubMed2002

Annexin 6 immunoreactivity in select cell populations in the rat brain.

We examined the distribution of annexin 6 (ANX6) in rat brain with immunohistochemistry (IHC). Several neuronal cell populations were intensely labeled with the ANX6 monoclonal antibody (MAb), including layer 5 of neocortex, the lateral septum, the lateral hypothalamic area, the red nucleus, and the Purkinje cell layer in cerebellum. Neuronal immunolabeling was localized to the nucleus and the cytosol. Darkly stained ANX6-immunoreactive glia, with the morphology characteristic of astrocytes, were abundant in the hippocampus, substantia nigra reticulata, and cerebellum. Evidence suggests that ANX6 may function in neuronal and glial calcium-dependent processes.

Animals↗

PubMed2002

Acute disruption of select steroid receptor coactivators prevents reproductive behavior in rats and unmasks genetic adaptation in knockout mice.

Estrogen (E) and progesterone exert profound influence on development and reproduction. In vitro, steroid receptor coactivators (SRCs) are nuclear proteins that interact with DNA-bound steroid receptors to potentiate their transcriptional efficiency. We examined the effects of antisense oligonucleotides to SRC-1, SRC-2, and SRC-3 on female sexual behavior and steroid receptor-mediated transcription. Rat (r) SRC-1, rSRC-2, and rSRC-3 genes were cloned. Our results reveal a significant inhibitory effect by antisense (AS) to SRC-1 and SRC-2, but not SRC-3, on hormone-induced reproductive behavior. Importantly, sexual behavior was attenuated through estrogen receptor alpha (ERalpha)-dependent, rather than progesterone receptor (PR)-dependent, transcription, as E failed to induce the synthesis of PR content in the medial basal hypothalamus, and immunoreactive PR in the ventromedial nucleus were depleted in tissue from rSRC-1-AS- and rSRC-2-AS-treated, but not rSRC-3-AS-treated, rats primed with E. Consistent with interruption of ERalpha-induced transcription, high dose of E and epidermal growth factor alone failed to induce sexual behavior in females treated with either rSRC-1-AS or SRC-2-AS. Immunoreactive SRC-1 and SRC-2, but not SRC-3, proteins were abundant in the ventromedial nucleus, thus demonstrating that the biological activities of hypothalamic steroid receptors are selectively regulated by regional distribution of specific SRCs. As SRC-1 knockout mice have only a slight loss in reproductive function, the possibility that genetic adaptation occurs during development was tested. Mouse (m) SRC-1-AS suppressed lordosis in wild-type, but not SRC-1, knockout mice, whereas mSRC-2-AS suppressed behavior in both genotypes. mSRC-3-AS had no effect in either genotype, and SRC-3 knockout mice exhibited full receptivity. Collectively, the findings clearly implicate dual regulation of ERalpha-dependent function by SRC-1 and SRC-2 in the intact female brain. In the genetic, but not acute, absence of SRC-1, up-regulation of SRC-2 serves as a critical adaptive mechanism during female development.

Adaptation, Physiological↗

PubMed2002

[Serrated adenoma of large intestine: report of 7 cases].

From December 2000 to April 2001, 859 patients were examined with coloscopy in our endoscopy centre and 188 cases of adenoma were diagnosed. Among the 188 patients, 7 were found with serrated adenoma that had been confirmed pathologically, including 6 male and 1 female patients, aged 32 to 53 with an average of 44.7 years. All the 7 cases were identified as having single focal lesion, among which 3 were found in the rectum, 1 in the transverse colon, 2 in the ascending colon and 1 in the cecum. The diameter of the lesions ranged from 8 to 27 mm with an average of 15.4 mm.

Adenoma↗

PubMed2002

[The diagnosis and treatment of 25 cases of laterally spreading tumor of the large intestine].

Laterally spreading tumor (LST) originates from the large intestine mucosa with prominent lesions that mainly extend laterally other than vertically. The pathological morphology and evolvement of this disease distinguish itself from other adenomas, and its close association with colorectal cancer has been noted. Up till now, no report on LST involving the large intestine has been available in China, therefore we presently report our experience in the diagnoses and treatment of 25 LST patients (26 lesions) identified with conventional endoscopy and mucosa staining during the period from Nov, 2000 to Oct, 2001. Among the 26 lesions, 11 were classified into granular homogeneous type, 15 into nodular mixed type, and 3 patients were found to have intramucosa carcinoma and 2 serrated adenoma. The biggest lesion was 60 mmx70 mm, the smallest being 11 mmx12 mm, and 6 lesions were within the range of 11 to 20 mm, 9 within 21 to 30 mm with the rest 11 lesions exceeding 31 mm in diameter. Type IV pit pattern was predominant in the the 26 lesions, accounting for a proportion of 61.54% (16/26). Two lesions with V(A) pit pattern and 1 with IV pattern were pathologically diagnosed to be intramucosa carcinoma, and 8 with type III(L) pit pattern were tubulovillous adenoma. Immediate or elective endoscopic mucosa resection or partitioned mucosa resection was performed in the 25 cases without incidences of the complications as bleeding or perforation.

Adult↗