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Biomedical subjects

Q Gao

Publications and source records attributed to Q Gao.

At least 73 records · Page 4Linked to original sources
PubMed2001

Clinical observation on preservation of lens anterior capsule in reduction of complications associated with silicone oil.

PURPOSE: To observe the effect of preservation of anterior capsule on the incidence of complications associated with silicone oil. METHODS: 82 patients (82 eyes) accepted trans pars plana vitrectomy (TPPV) combined with lensectomy of whom, 30 eyes with preservation of anterior capsule (PAC) and 52 eyes with no preservation of anterior capsule (NPAC). Analysis of the incidence of complications associated with use of oil. RESULTS: The incidence rate was 50.0% in NPAC group, and 23.3% in PAC group (P < 0.025). There were secondary glaucoma (21.1%), band keratopathy (13.5%) and corneal decompensation (9.6%) in NPAC group, while there was none of them in PAC group. CONCLUSIONS: Preservation of anterior capsule is an effective method to reduce the complications associated with silicone oil.

Adolescent↗
PubMed2001

Effect of hypericin on confocal imaging of Ca2+ signaling in cultured human retinal pigment epithelium.

PURPOSE: To investigate the mechanism of the Ca2+ signaling in cultured human retinal pigment epithelial (RPE) cells with the protein kinase C(PKC) specific inhibitor-hypericin stimulation. METHODS: Cultured human RPE cells were analyzed using the fluorescence Ca2+ dye fluo-3 AM and laser scanning confocal microscope(LSCM) after stimulation with 100 nM phorbol 12-myristate 13-acetate(PMA) and (or) 5 concentrations of hypericin(1, 2, 3, 4 and 5 microM). RESULTS: The normal fluorescence in RPE cells was strong and distributed throughout the cells. The nucleus appeared to be more fluorescent than the cytoplasm. After stimulation with PMA alone or 5 concentrations of hypericin, a rapid decrease in flurescence intensity was observed. There was no obvious difference in decreased curve among 5 concentrations. However, after stimulation with a 24 hr preincubation of PMA and 5 concentrations of hypericin, a further decrease was not observed. CONCLUSION: Fluo-3 AM appears to be a good indicator of the change in Ca2+ occurring in RPE cells and hypericin is a strong inhibitor of Ca2+ influx channel. Hypericin has potential as a therapeutic drug for proliferative vitreoretinopathy(PVR), the inhibitory effect on PVR might be caused by blocking the PKC activity and inhibiting Ca2+ influx pathway.

Adult↗
PubMed2001

[Investigation on genotype constitution of different Plasmodium vivax isolates and its geographical distribution in China].

OBJECTIVE: To investigate the population constitution and geographical distribution of Plasmodium vivax in China using molecular technique. METHODS: Blood-spot filter paper samples with related epidemiological data were collected from vivax malaria patients living in malarious area of 10 provinces (autonomous region) in China. Semi-nested- or nested-allelic-specific PCR genotyping method was used to identify CSP genotypes, families and types of Plasmodium vivax of each isolate from these patients. RESULTS: Of 384 field isolates of Plasmodium vivax, 258 temperate zone family strains were identified, including 14 allelic variant genotypes spreading among 10 sampling provinces; allelic variants sized less than 731 bp were only seen in 5 provinces in southern China; 79 tropical zone family strains including 5 genotypes were also distributed in 5 provinces of southern China south to 25 degrees N. lat; and 14 PV Type-2 strains including 2 genotypes were found in some areas of Hainan and Yunnan Provinces. In addition, 33 isolates from genotype-mixed infections were revealed. CONCLUSION: At present, area north to 25 degrees N. lat. of the country is the sole area prevalent for Plasmodium vivax family strains of temperate zone; there is overlapping distribution of P. v. of temperate zone family and tropical zone family of this parasite in the southern China south to 25 degrees N. lat; where the most complex isolate constitution is in Yunnan and Hainan Provinces, and PV Type-2 strains have been found in some areas of the two provinces. Besides, there were 2 groups of genotype with distinct geographic distribution feature within the temperate zone family.

Animals↗
PubMed2001

[The protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression].

OBJECTIVE: To investigate the protein expression of B-cell lymphoma/leukemia-2(Bcl-2) and B-cell lymphoma/leukemia-x long(Bcl-x1) in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression. METHODS: Using May-Grünwald-Giemsa (MGG) method and immunohistochemical method, the protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps from patients treated with beclomethasone dipropionate treatment and patients without any treatment was compared. RESULTS: (1) Nasal polyp tissues from patients without treatment had more eosinophils than those from patients with treatment(P < 0.01). (2) No protein expression of Bcl-2 was observed in all 52 patients. (3) 20.0% patients with treatment had the expression of Bcl-x1, whereas 48.1% patients without treatment had the expression. The difference between these two groups was significant(P < 0.05). CONCLUSION: These data suggest that Bcl-x1 may act as an anti-apoptotic molecule in eosinophils and corticosteroids induce eosinophil apoptosis through suppressing the expression of Bcl-x1.

Adolescent↗
PubMed2000

High-throughput detection of unknown mutations by using multiplexed capillary electrophoresis with poly(vinylpyrrolidone) solution.

Single-nucleotide polymorphism detection has been the focus of much attention recently. Although many methods have been reported, low-cost, high-throughput, and high-detection-rate methods are still in demand. We present a fast and reliable mutation detection scheme based on temperature-gradient capillary electrophoresis. A large temperature gradient (10 degrees C) was applied with a precision of 0.02 degrees C and a temperature ramp of 0.7 degrees C/min. Multiple unlabeled samples from PCR were injected and analyzed. Ethidium bromide was used as the intercalating dye for laser-induced fluorescence detection. Mutations can be recognized by comparing the electrophoretic patterns of the heteroduplex with that of a homoduplex reference without prior knowledge of the exact type of mutation present. Mutations in all five test samples were successfully detected with high confidence. This scheme is demonstrated in 96-capillary array electrophoresis for screening single-point polymorphism in large numbers of samples prior to full sequencing of only the positive samples to identify the nature of the mutation.

DNA↗
PubMed2000

Occurrence of Bothriocephalus acheilognathi in cyprinid fish from three lakes in the flood plain of the Yangtze River, China.

Cyprinid fish, Hemiculter leucisculus, Cultrichthys erythropterus and Culter dabryi, were sampled from Liangzi, Honghu and Tangxun lakes in the flood plain of the Yangtze River. The cestode Bothriocephalus acheilognathi Yamaguti, 1934 was found in the 3 lakes, but C. erythropterus sampled from Liangzi lake was found uninfected due probably to the small sample size. Findings of the cestode in the 3 lakes represent the first record of the parasite in the flood plain of the Yangtze River, indicating that B. acheilognathi may be distributed much wider in China than previously recognized.

Animals↗
PubMed2000

PKN binds and phosphorylates human papillomavirus E6 oncoprotein.

The high risk human papillomaviruses (HPVs) are associated with carcinomas of cervix and other genital tumors. Previous studies have identified two viral oncoproteins E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high risk HPV E6 protein to immortalize human mammary epithelial cells has provided a single gene model to study the mechanisms of E6-induced oncogenic transformation. In recent years, it has become clear that in addition to E6-induced degradation of p53 tumor suppressor protein, other targets of E6 are required for mammary epithelial cells immortalization. Using the yeast two-hybrid system, we have identified a novel interaction of HPV16 E6 with protein kinase PKN, a fatty acid- and Rho small G protein-activated serine/threonine kinase with a catalytic domain highly homologous to protein kinase C. We demonstrate direct binding of high risk HPV E6 proteins to PKN in wheat-germ lysate in vitro and in 293T cells in vivo. Importantly, E6 proteins of high risk HPVs but not low risk HPVs were able to bind PKN. Furthermore, all the immortalization-competent and many immortalization-non-competent E6 mutants bind PKN. These data suggest that binding to PKN may be required but not sufficient for immortalizing normal mammary epithelial cells. Finally, we show that PKN phosphorylates E6, demonstrating for the first time that HPV E6 is a phosphoprotein. Our finding suggests a novel link between HPV E6 mediated oncogenesis and regulation of a well known phosphorylation cascade.

Amino Acid Substitution↗
PubMed2000

Automated parallel DNA sequencing on multiple channel microchips.

We report automated DNA sequencing in 16-channel microchips. A microchip prefilled with sieving matrix is aligned on a heating plate affixed to a movable platform. Samples are loaded into sample reservoirs by using an eight-tip pipetting device, and the chip is docked with an array of electrodes in the focal plane of a four-color scanning detection system. Under computer control, high voltage is applied to the appropriate reservoirs in a programmed sequence that injects and separates the DNA samples. An integrated four-color confocal fluorescent detector automatically scans all 16 channels. The system routinely yields more than 450 bases in 15 min in all 16 channels. In the best case using an automated base-calling program, 543 bases have been called at an accuracy of >99%. Separations, including automated chip loading and sample injection, normally are completed in less than 18 min. The advantages of DNA sequencing on capillary electrophoresis chips include uniform signal intensity and tolerance of high DNA template concentration. To understand the fundamentals of these unique features we developed a theoretical treatment of cross-channel chip injection that we call the differential concentration effect. We present experimental evidence consistent with the predictions of the theory.

Automation↗
PubMed2000

Characterization of the gtfB and gtfC promoters from Streptococcus mutans GS-5.

We have characterized the promoter regions of the gtfB and gtfC genes from Streptococcus mutans GS-5. Using a plasmid-based reporter system, we discovered that the gtfC promoter is an order of magnitude stronger than the gtfB promoter. In addition, we found that a variety of growth conditions failed to affect or discriminate between the expression of the two promoters. Only during the various phases of growth could we demonstrate significant changes in expression. We conclude that gtfB and gtfC promoters are coordinately expressed.

Base Sequence↗
PubMed2000

Prevalence of BRCA1 and BRCA2 mutations among clinic-based African American families with breast cancer.

To define the prevalence and relative contributions of BRCA1 and BRCA2 mutations among African American families with breast cancer, we analyzed 28 DNA samples from patients identified through two oncology clinics. The entire coding regions of BRCA1 and BRCA2 were screened by protein truncation test, heteroduplex analysis, or single-stranded conformation polymorphism followed by DNA sequencing of variant bands. Deleterious protein-truncating BRCA1 and BRCA2 mutations were identified in five patients or 18% of the entire cohort. Only 8% (1 of 13) of women with a family history of breast cancer, but no ovarian cancer, had mutations. The mutation rates were higher for women from families with a history of breast cancer and at least one ovarian cancer (three of six, 50%). One woman with a family history of undocumented cancers was also found to carry a deleterious mutation in BRCA2. The spectrum of mutations was unique in that one novel BRCA1 mutation (1625del5) and three novel BRCA2 mutations (1536del4, 6696delTC, and 7795delCT) were identified. No recurrent mutations were identified in this cohort, although one BRCA2 (2816insA) mutation had been previously reported. In addition, two BRCA1 and four BRCA2 missense mutations of unknown significance were identified, one of which was novel. Taken together with our previous report on recurrent mutations seen in unrelated families, we conclude that African Americans have a unique mutation spectrum in BRCA1 and BRCA2 genes, but recurrent mutations are likely to be more widely dispersed and therefore not readily identifiable in this population.

Adult↗
PubMed2000

Convergent projections of Drosophila olfactory neurons to specific glomeruli in the antennal lobe.

Candidate Drosophila olfactory receptors (ORs) provide molecular tools to investigate how the organization of the Drosophila olfactory system determines the coding of olfactory stimuli. Neurons in the third antennal segment and maxillary palp appear to express different ORs. Individual olfactory neurons send axonal projections to glomeruli in the antennal lobe. Using transgenic flies, we provide evidence that the neurons expressing a given OR gene, which have cell bodies distributed among neurons expressing other ORs, converge in their projections to topographically fixed glomeruli in the antennal lobe. This convergence allows for the formation of an odotopic map in the antennal lobe whose organization could provide a basis for olfactory discrimination in Drosophila.

Animals↗
PubMed2000

Susceptibility gene for familial acute myeloid leukemia associated with loss of 5q and/or 7q is not localized on the commonly deleted portion of 5q.

The molecular mechanism for the occurrence of leukemia in multiple members of a family has not been fully elucidated but data support the contribution of highly penetrant mutations in leukemia susceptibility genes. We have investigated the genetic etiology of an unusual three-generation family with apparent autosomal dominant transmission of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) accompanied by somatic loss of the long arm of chromosome 5 and/or loss of heterozygosity (LOH) analysis and fluorescence in situ hybridization (FISH) of leukemia cells have been performed, confirming acquired hemi- and homozygous deletion of the long arm of chromosome 5. However, the chromosome lost in the observed LOH event is from the affected parent, in contradiction to the expectation for a two-hit hypothesis involving a tumor suppressor gene. Furthermore, genetic linkage has been performed at 5q31-33 as well as other loci (21q22 and 16q21-23.2) previously implicated in familial leukemia. In this family, linkage analysis excludes loci at 5q31-33 and 21q22, but localization to 16q21-23.2 cannot be excluded. We observed a maximum multipoint LOD score of 1.19 between marker D16S265 and D16S503 at 16q22 (P = 0.03), suggesting possible linkage to this locus. Considering this family and the previous 16q-linked family together, the linkage of a leukemia susceptibility gene to 16q22 achieved an LOD score of 3.63 at D16S265 with theta = 0. Thus, somatic deletion of the long arm of chromosome 5 appears as a necessary but surprisingly noncausative event for onset of AML and MDS in this family, thereby confirming a multistep etiology in which chromosome 5 plays an important secondary role.

Acute Disease↗
PubMed2000

Preliminary studies on parkin gene deletion at exons 1 to 6 in Chinese patients with praecox Parkinson's disease.

OBJECTIVE: To search parkin gene deletion mutations at exons 1 to 6 in Chinese patients with praecox Parkinson's disease (PPD) and analyze them together with the clinical features of PPD. METHODS: DNA was extracted from peripheral blood of PPD patients; deletion mutations of parkin gene were identified by PCR amplification and agarose gel electrophoresis. The clinical data were analyzed together with the above information. RESULTS: Out of 21 patients, 2 had exon 1 deletion, 2 exon 4 deletion, and 1 exon 6 deletion. The mean age of the patients with deletion mutation was 45.7+/-1.8 years. All of the patients who had parkin gene deletion mutation had tremor, rigidity and bradykinesia, but athetosis and family history of PD were not found. In additon, the deletion mutations of parkin gene at exons 2, 3, 5, were not found. CONCLUSION: There are deletion mutations of parkin gene at exons 1,4,6 in PPD of Chinese, and such deletions generally happen on middle-aged patients.

Adolescent↗
PubMed2000

[Effect of lanthanum on growth and biochemical property of Sclerotinia sclerotiorum].

The study shows that La2O3 at a concentration of 30-450 mg.L-1 could inhibit the growth of S. sclerotiorum in both solid and liquid media and the inhibition effect was increased with its increasing concentration. The activity of pectinase produced by S. sclerotiorum in liquid medium was also increased with increasing La2O3 concentration.

Ascomycota↗
PubMed2000

[Clinical study on tangweikang capsule in treating diabetic nephropathy].

OBJECTIVE: To observe the effect of Tangweikang capsule (TWKC) in treating diabetic nephropathy (DN). METHODS: The 119 patients enrolled were divided into 2 groups, 78 patients in the TWKC group treated with TWKC and 41 patients in the control group treated with Captopril. The changes of symptom score, urinary microprotein series (urinary albumin excretion rate, Tamm-horsfall protein and beta 2-microglobulin), blood glucose, kidney function, blood lipid, angiotensin I (A I) and II (A II), atrial natriuretic polypeptide (ANP), thromboxane B2(TXB2), 6-keto-prostaglandin F1 alpha, endothelin 1 (ET-1) and collagen IV in patients after treatment were observed. RESULTS: The total effective rate in the TWKC group was 84.62%, which was superior to that in the control group (70.73%, P < 0.05). TWKC also showed better effects in improving clinical symptoms, lowering blood glucose, urinary microprotein series, blood lipid, A I, A II, ANP, ET-1 and collagen IV, ameliorating kidney function, and adjusting dynamic equilibrium of thromboxane-prostacyclin system, as compared with the control group (P < 0.05 or P < 0.01). CONCLUSION: TWKC could lower the levels of blood glucose and lipid, improve the glucose and lipid metabolism, regulate the microcirculation, ameliorate the degree of kidney damage, therefore, it showed a better effect in treating diabetic nephropathy.

Adult↗
PubMed2000

[The function of benzol peroxide in the induction of Syrian golden hamster tongue carcinoma by chemical carcinogen].

OBJECTIVE: To testify the function of promoter(benzol peroxide) in the induced tongue carcinogenesis of Syrian golden hamster as well as the function of carcinogen (DMBA). METHODS: In this study, group 1: 20% benzoyl peroxide in acetone solution was brushed to the right tongue border of Syrian golden hamster, followed by 0.5% 7, 12-dimethybenzanthrancene(DMBA) in acetone, twice a week, lasting 20 weeks. Group 2: 0.5% 7,12-dimethybenzanthrancene(DMBA) in acetone was painted on the right tongue border of golden Syrian hamster in the manner of group 1. Group 3: 20% benzoyl peroxide in acetone solution was used with mentioned methods. RESULTS: Group 2: showed 90% (27/30) carcinogenesis-rate in tongue of Syrian golden hamster. While it was 100% (30/30) of induced tongue carcinoma and 3/30 lymph node metastasis was found in group 1. No tongue carcinogenesis was found in group 3. The former two groups had the manifestations of hyperplasia of epithelium cell, carcinoma in situ, invasive and cervical lymph node metastatic carcinoma in the process of experiment, but it was 2 weeks shorter in group 1 than that of group 2. Both groups had the same features under eye and light microscope. The samples were high-differentiated squamous cell carcinoma histologically through HE stain. CONCLUSION: This study indicated that benzoyl peroxide could increase carcinogenesis of golden hamster tongue which induced by DMBA. Consideration of promoting agent should be taken in carcinogenesis as well as carcinogen.

9,10-Dimethyl-1,2-benzanthracene↗