Biomedical subjects

B Yao

Publications and source records attributed to B Yao.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Purification and properties of neutral phytase form Bacillus subtilis].

A strain Bacillus subtilis producing neutral phytase was screened from soil. The protein of phytase was purified by HPLC. Optimal pH value and temperature of the phytase for its activity were 7.5 and 55 degrees C, respectively. The Km values of the phytase for dodecasodium phytate under 37 degrees C was 0.19 mmol/L. The molecule weight of the phytase protein was determined as about 45 kD by SDS-PAGE. The N-terminal amino acids sequence of the phytase protein was determined as Lys-His-Lys-Leu-Ser-Asp-Pro-Tyr-His-Phe-Thr by amino acids sequence analysis.

6-Phytase↗

PubMed2001

[The effect of perindopril in treatment of early diabetic nephropathy with normal blood pressure and microalbuminuria].

OBJECTIVE: To study the effect of perindopril in decreasing the urinary albumin excretion rate (AER) and protecting the renal function in normotensive early diabetic nephropathy. METHODS: 52 diabetic patients with AER between 20 to 200 microg/min, were treated with dietary regimen, oral antihyperglycemic agents or/ and insulin till their fasting blood glucose (FBG) was < 7.0 mmol/L and postprandial blood glucose (PBG) < 10.0 mmol/L. They were then divided randomly into two groups. Group A was a control group (25 cases), the patients were administered with placebo, group B was a treatment group (27 cases), the patients were administered with perindopril (4 mg/day) FBG, PBG, glycosylated haemoglobin A1c (HbA1c), AER, blood pressure (MAP) and blood creatinine (Cr) were examined immediately and 3, 6, 12 and 18 months after the treatment. RESULTS: In group A, AER was significantly increased after 12 and 18 months than at beginning, they were (52.3 +/- 8.6) microg/min and (60.4 +/- 9.0) microg/min vs (44.2 +/- 6.8) microg/min (P < 0.05). In group B, after being treated with perindopril, AER estimated 3, 6, 12 and 18 months later were (20.3 +/- 5.6) microg/min, (22.1 +/- 6.1) microg/min, (21.3 +/- 5.9) microg/min and (20.8 +/- 5.7) microg/min respectively, all were significantly lower those that of group A in the same period (P < 0.05) and also significantly lower than those at the beginning (P < 0.05). CONCLUSION: Perindopril has good effects in decreasing AER in normotensive early diabetic nephropathy and in protecting the renal function.

Adult↗

PubMed2000

[Molecular biology and gene engineering of phytase].

Phytase is a new-style enzyme used in monogastric animal feed. The addition of phytase to feed can increase phosphorus availability, decrease environmental phosphorus pollution and improve the performance of animal. This paper reviews the research progress and trend in recent studies related to molecular biology and gene engineering of phytase.

6-Phytase↗

PubMed2000

[A study on screening and high density cell cultivation of a yeast strain Kluyveromyces with high inulinase yielding and its enzymology properties].

A yeast strain Kluyveromyces with high inulinase yield was screened. The highest inulinase activity of 288.78 u/mL was reached when a high cell density cultivation method was developed for inulinase production. It was 6.8 times higher than the highest level reported in the same species. The activity ratio of its inulinase to invertase was 1/24.72, the Km values were 13.3 mmol/L and 62.6 mmol/L when inulin and sucrose were used as substrate, respectively; The optimum pH value was 4.4, this enzyme also showed a good pH adaptability and stability, i.e. more 90% of the highest level was maintained between pH 3.8 and 5.6; The optimum reaction temperature was 55 degrees C, higher activity was maintained between 50-57.5 degrees C, its half life period was 16 hours at 55 degrees C; It was found for the first time that addition of magnesium ion into the reaction system increased the enzyme activity by 11%.

Cells, Cultured↗

PubMed2000

[Insect-resistant transgenic poplar expressing AaIT gene].

Insect-specific scorpion neurotoxin AaIT gene inserted into a binary vector was transferred into a hybrid poplar clone N-106(P. deltoides x P. simonii) growing in the Southern of China. We obtained sixty-two regenerated plants by Agrobacterium tumefaciens transferring system. PCR and PCR-Southern analysis showed that AaIT gene was incorporated into the genome of some recovered poplar plants. One of the transformed plants named A5 was significantly resistant to feeding by first instar larvae of Lymantria dispar, compared with the untransformed control plant. It caused a decrease in leaf consumption by larvae, a lower larval weight gain and a higher larval motality rate of Lymantria dispar. ELISA analysis proved that AaIT gene was expressed in this transfomed poplar plant.

Animals↗

PubMed2000

[Does ureteroscopy still play a role in the treatment of ureteral calculi?].

OBJECTIVES: To evaluate the results obtained by ureteroscopy to treat ureteric stones and the related complications. MATERIALS AND METHODS: 74 ureteroscopies were studied retrospectively, including 62 cases of pelvic ureteric stones. In situ fragmentation was necessary in 28.4% of cases. Success was defined as the absence of stones for one month after ureteroscopy. Success rates were analysed according to size and site of the stone, the need for fragmentation and the patient's sex. RESULTS: Morbidity was 6.8%. Success was obtained in 60.8% of cases: 72.7% in women and 55.8% in men. The mean diameter of successfully treated stones was statistically smaller (6.2 +/- 2.1 mm) than that of stones with a poor result (7.8 +/- 3.7 mm) (p = 0.044, Spearman). CONCLUSIONS: The size and site of the stone and the patient's sex influence the results of ureteroscopy. Ureteroscopy for stone disease remains a topical modality after failure of extracorporeal lithotripsy, but also in the case of poor access of an effective lithotriptor.

Adult↗

PubMed1999

Structure/function of the beta-barrel domain of F1-ATPase in the yeast Saccharomyces cerevisiae.

The first 90 amino acids of the alpha- and beta-subunits of mitochondrial F1-ATPase are folded into beta-barrel domains and were postulated to be important for stabilizing the enzyme (Abrahams, J. P., Leslie, A. G., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628). The role of the domains was studied by making chimeric enzymes, replacing the domains from the yeast Saccharomyces cerevisiae enzyme with the corresponding domains from the enzyme of the thermophilic bacterium Bacillus PS3. The enzymes containing the chimeric alpha-, beta-, or alpha- and beta-subunits were not functional. However, gain-of-function mutations were obtained from the strain containing the enzyme with the chimeric PS3/yeast beta-subunit. The gain-of-function mutations were all in codons encoding the beta-barrel domain of the beta-subunit, and the residues appear to map out a region of subunit-subunit interactions. Gain-of-function mutations were also obtained that provided functional expression of the chimeric PS3/yeast alpha- and beta-subunits together. Biochemical analysis of this active chimeric enzyme indicated that it was not significantly more thermostable or labile than the wild type. The results of this study indicate that the beta-barrel domains form critical contacts (distinct from those between the alpha- and beta-subunits) that are important for the assembly of the ATP synthase.

Amino Acid Sequence↗

PubMed1999

Organization of geniculate and trigeminal ganglion cells innervating single fungiform taste papillae: a study with tetramethylrhodamine dextran amine labeling.

Single gustatory nerve fibers branch and innervate several taste buds. In turn, individual taste buds may receive innervation from numerous gustatory nerve fibers. To evaluate the pattern of sensory innervation of fungiform papilla-bearing taste buds, we used iontophoretic fluorescent injection to retrogradely label the fibers that innervate single taste papillae in the hamster. For each animal, a single taste papilla was injected through the gemmal pore with 3.3% tetramethylrhodamine dextran amine. Fungiform papillae either at the tongue tip (0.5-1.5 mm from the tip) or more posteriorly (1.5-3.0 mm from the tip) were injected. After one to seven days survival, the geniculate and trigeminal ganglia and the tongue were sectioned and examined for labeled cells and fibers, respectively. Analysis of the number and topographic distribution of geniculate cells innervating single taste papillae, shows that: (i) 15 +/- 4 (S.D.) ganglion cells converge to innervate a single fungiform taste bud; (ii) more ganglion cells innervate anterior- (range: 13-35 cells) than posterior-lying buds (range: five to 12 cells), which, in part, may be related to bud volume (microm3); and (iii) ganglion somata innervating a single taste bud are scattered widely within the geniculate ganglion. Analysis of labeled fibers in the tongue demonstrated that two to eight taste buds located within 2 mm of the injected taste bud share collateral innervation with the injected taste bud. Since all buds with labeled fibers were located in close proximity (within a 2-mm radius), widely dispersed geniculate ganglion cells converge to innervate closely spaced fungiform taste buds. Trigeminal ganglion (mandibular division) cells were also labeled in every case and, as with the geniculate ganglion, a dispersed cell body location and collateralization pattern among papillae were observed. This study shows that iontophoresis of tetramethylrhodamine dextran amine, selectively applied to individual peripheral receptor end-organs, effectively locates sensory ganglion cells in two different ganglia that project to these sites. Moreover, the marker demonstrates collateral branches of sensory afferents associated with the labeled fibers and the nearby receptor areas innervated by these collaterals. The labeling of single or clusters of receptor cells, as well as identified sensory afferents, affords future possibilities for combining this technique with immunocytochemistry to establish the relationships of innervation patterns with neurotransmitters and neurotropic substances within identified cells.

Afferent Pathways↗

PubMed1999

The role of the amino-terminal beta-barrel domain of the alpha and beta subunits in the yeast F1-ATPase.

The crystal structure of mitochondrial F1-ATPase indicates that the alpha and beta subunits fold into a structure defined by three domains: the top beta-barrel domain, the middle nucleotide-binding domain, and the C-terminal alpha-helix bundle domain (Abrahams et al., 1994); Bianchet et al., 1998). The beta-barrel domains of the alpha and beta subunits form a crown structure at the top of F1, which was suggested to stabilize it (Abrahams et al. 1994). In this study, the role of the beta-barrel domain in the alpha and beta subunits of the yeast Saccharomyces cerevisiae F1, with regard to its folding and assembly, was investigated. The beta-barrel domains of yeast F1alpha and beta subunits were expressed individually and together in Escherichia coli. When expressed separately, the beta-barrel domain of the beta subunit formed a large aggregate structure, while the domain of the alpha subunit was predominately a monomer or dimer. However, coexpression of the beta-barrel domain of alpha subunit with the beta-barrel domain of beta subunit, greatly reduced the aggregation of the beta subunit domain. Furthermore, the two domains copurified in complexes with the major portion of the complex found in a small molecular weight form. These results indicate that the beta-barrel domain of the alpha and beta subunits interact specifically with each other and that these interactions prevent the aggregation of the beta-barrel domain of the beta subunit. These results mimic in vivo results and suggest that the interactions of the beta-barrel domains may be critical during the folding and assembly of F1.

Amino Acid Sequence↗

PubMed1999

[Problems produced by the use of antitubercular agents in a reference service for HIV/AIDS in Abidjan (Côte d'Ivoire)].

This study reports on the experience using antituberculosis drugs in a HIV/AIDS reference service in Abidjan during a 64 month period. Prevalence of tuberculosis is 1.9% out of a total of 23,957 patients. The annual incidence rate increased slowly from 0.9% in 1990 to 3.5% in 1995. Seropositivity to HIV is 90.8%. Predominant locations of tuberculosis are pulmonary (60.3%), extrapulmonary (19.7%) and multifocal or disseminated (20%). The average period of diagnosis (9.9 days) and average duration of antituberculosis treatment in hospital (11.8 days) are similar whatever the serological status and the location of the infection may be. However, the mortality rate is more important in HIV positive patients (39.7%) than in HIV negative (17.6%) p = 0.01. The decision to treat is taken by infectiologists only in 88% of the cases, by pneumologists only in 2.5%, and both by infectiologists and pneumologists in 9.5%. Side-effects due to antituberculosis drugs were noticed in 19 patients leading to an interruption of the treatment in 10 cases. The authors recommend that health personnel be trained for the management of tuberculosis.

Acquired Immunodeficiency Syndrome↗

PubMed1999

[Cytogenetic analysis and bcr/abl mRNA detection in chronic myeloid leukemia].

OBJECTIVE: To define the relationship between Ph chromosome and BCR/ABL mRNA expression in chronic myeloid leukemia (CML) patients, and compare cytogenetic analysis and PCR method. METHODS: Marrow or peripheral blood samples from 33 CML patients were analyzed by R banding technique and PCR method. Eleven patients who received allogeneic BMT or alpha-IFN + low dose HU were followed up. RESULTS: In 33 patients, 29 were Ph(+), 30 expressed BCR/ABL mRNA. In 6 patients who received BMT, 4 were Ph(-), 2 were Ph(+). However, 2 patients were (-), 4 were (+) by PCR method. In 5 patients who received alpha-IFN, the percentage of Ph(+) cells reduced after 6 and 12 months treatment than before treatment in 2 cases respectively. In 41 samples, 34 cases were consistent by 2 methods. CONCLUSION: Each method, Cytogenetic analysis or PCR has its advantage and defect. The better method are integration of 2 methods in diagnosis and treatment monitoring of CML patients, so that provide real and beneficial information for clinic.

Adolescent↗

PubMed1999

[Studies on reduction of Au3+ by bacteria for preparing gold catalyst].

The strain D01, screened from different source bacterial strains, has relatively strong ability of adsorbing Au3+. The strain D01 was identified as Bacillus megatherium D01 and still grew well in the medium containing 600 mg/L Au3+. The results of electrochemical reaction indicated that the strain D01 had a strong ability of reduction. It could reduce the Au3+/alpha-Fe2O3(precursor of the gold catalyst) to highly dispersive Au0/alpha-Fe2O3 catalyst which could catalyze the reaction of CO + O2-->CO2.

Adsorption↗

PubMed1998

Inhibition of rabbit duodenal bicarbonate secretion by ulcerogenic agents: histamine-dependent and -independent effects.

BACKGROUND & AIMS: The gastroduodenal epithelium is protected from acid-peptic damage, in part, by its ability to secrete bicarbonate. Patients with duodenal ulcer disease have impaired proximal duodenal mucosal bicarbonate secretion. We have shown in vitro that histamine inhibits prostaglandin-stimulated bicarbonate secretion in rabbit duodenal mucosa via histamine H2 receptors and enteric nerves. In this study we examined whether the proulcerogenic compounds aspirin or ethanol regulate duodenal bicarbonate secretion and the involvement of histamine. METHODS: Bicarbonate secretion by rabbit proximal duodenal mucosa was examined in vitro in Ussing chambers. RESULTS: Aspirin and ethanol decreased basal and prostaglandin-stimulated bicarbonate secretion; the latter effect was specific for prostaglandin. The inhibitory effects of the two ulcerogenic compounds were at least additive. Ranitidine and tetrodotoxin abolished the inhibitory effects on stimulated, but not basal, secretion. Aspirin and ethanol also induced release of duodenal histamine. CONCLUSIONS: Aspirin and ethanol act by two distinct pathways to impair duodenal bicarbonate secretion. Both agents inhibit basal secretion via a histamine-independent and neurally independent pathway while they inhibit prostaglandin E2-stimulated secretion via histamine release, likely from mast cells, and actions on enteric nerves. Our findings may be of relevance to the understanding and potential treatment of nonsteroidal anti-inflammatory drug-associated mucosal injury.

Animals↗

PubMed1998

Neural cell adhesion molecule, neuron-specific enolase and calcitonin gene-related peptide immunoreactivity in hamster taste buds after chorda tympani/lingual nerve denervation.

Hamster fungiform papilla taste buds persist in an atrophic form following sensory denervation. While atrophic and innervated taste buds are morphologically similar, it is not known whether their gemmal cells have similar molecular characteristics. Three neurochemicals, neural cell adhesion molecule, neuron-specific enolase, and calcitonin gene-related peptide have been implicated in trophic phenomena, synaptogenesis and cell recognition in neurons and sensory neuroepithelia. The present study uses immunocytochemical localization of these molecular markers to characterize normal and denervated fungiform taste buds following unilateral chorda tympani/lingual nerve denervation in hamsters. In normal taste buds, immunoreactivity to neural cell adhesion molecule, neuron-specific enolase, and calcitonin gene-related peptide was present in a group of cells located centrally in the bud as well as in fungiform nerve fibres and endings. After denervation, gemmal cell immunoreactivity to all three markers was reduced and often confined to a single or a few bud cell(s). Also, fibre staining was absent except for sparse calcitonin gene-related peptide-immunoreactive fibres associated with blood vessels and within the fungiform papillae. These remaining fibres may be autonomic or somatomotor in origin. These results indicate that sensory denervation of hamster taste buds reduces, but does not wholly eliminate the immunoreactivity of surviving gemmal cells to neural cell adhesion molecule, neuron-specific enolase, and calcitonin gene-related peptide. While the number of taste bud cells expressing the markers appears to be nerve-dependent, immunoreactivity in sensory-denervated bud cells of hamster may reflect the influence of local tissue factors.

Animals↗

PubMed1998

Modulation of bicarbonate secretion in rabbit duodenum: the role of calcium.

Surface epithelial bicarbonate secretion protects the proximal duodenum from acid peptic injury. Cyclic adenosine monophosphate and calcium serve as intracellular mediators of intestinal transport. Experiments were performed to examine whether calcium participates in duodenal bicarbonate transport. Stripped duodenal mucosa from rabbits was studied in Ussing chambers. HCO3- transport was stimulated by the calcium ionophore A23187, carbachol, vasoactive intestinal peptide, prostaglandin E2, dibutyryl-cyclic adenosine monophosphate, and electrical field stimulation. A23187 stimulated HCO3- secretion and Isc; tetrodotoxin failed to inhibit this effect. The calcium-channel blocker verapamil abolished HCO3- secretion stimulated by carbachol, vasoactive intestinal peptide, and electrical field stimulation, but failed to alter basal, prostaglandin E2- or dibutyryl-cyclic adenosine monophosphate-stimulated HCO3- secretion. Therefore, calcium is likely required during stimulation of duodenal epithelial HCO3- transport by carbachol, vasoactive intestinal peptide, and electrical field stimulation. Prostaglandin E2 and dibutyryl-cyclic adenosine monophosphate appear to activate duodenal HCO3- secretion by a calcium-independent pathway(s).

Animals↗

PubMed1998

Image cytometric measurement of nuclear proliferation markers (MIB-1, PCNA) in astrocytomas. Prognostic significance.

Proliferative activity in astrocytomas, measured by image cytometry, was related to prognosis. Fifty-eight astrocytic neoplasms (grade 1 or 2, 11; grade 3, 31; glioblastoma multiforme, 16) were immunostained for Ki-67 (MIB-1; 1:50) and proliferating cell nuclear antigen (PCNA; prediluted). Proliferative activity (nuclear immunostain) was measured as the percentage positive nuclear area by image cytometry. With a median of 12.0% and 24.0% for MIB-1 and PCNA, respectively, for all astrocytomas, the mean percentage positive nuclear area for MIB-1 and PCNA was, respectively, 3.06% and 13.11% in low-grade (1 or 2) astrocytomas, 14.34% and 29.68% in high-grade (3) astrocytomas, and 18.77% and 44.11% in glioblastoma multiforme (grade 4). One-way analysis of variance showed a significant correlation between the histologic grade and MIB-1 and between the histologic grade and PCNA. The Cox Proportional Hazards Regression Model showed a statistically significant correlation between survival and MIB-1 and between survival and PCNA. Increasing proliferation correlated with shortened survival. Proliferation in astrocytomas, measured as MIB-1 and PCNA by image cytometry, correlates significantly with histologic grade and patient survival, providing useful additional information for determining the diagnosis and prognosis.

Adolescent↗

PubMed1997

Kinase suppressor of Ras is ceramide-activated protein kinase.

A proline-directed serine/threonine ceramide-activated protein (CAP) kinase mediates transmembrane signaling through the sphingomyelin pathway. CAP kinase reportedly initiates proinflammatory TNF alpha action by phosphorylating and activating Raf-1. The present studies delineate kinase suppressor of Ras (KSR), identified genetically in Caenorhabditis elegans and Drosophila, as CAP kinase. Mouse KSR, like CAP kinase, renatures and autophosphorylates as a 100-kDa membrane-bound polypeptide. KSR overexpression constitutively activates Raf-1. TNF alpha or ceramide analogs markedly enhance KSR autophosphorylation and its ability to complex with, phosphorylate, and activate Raf-1. In vitro, low nanomolar concentrations of natural ceramide stimulate KSR to autophosphorylate, and transactivate Raf-1. Other lipid second messengers were ineffective. Moreover, Thr269 the Raf-1 site phosphorylated by CAP kinase, is also recognized by KSR. Thus, by previously established criteria, KSR appears to be CAP kinase.

Amino Acid Sequence↗

PubMed1997

Studies on buffalo babesiosis in Hubei Province, China.

The present paper summarises our recent studies on buffalo babesiosis in the Hubei province of China. It describes the pathogen and the epidemiology of the disease, the tick vector and its biology, control, immunological diagnosis, methods of in vitro cultivation of the pathogen and their practical applications. The identify of the pathogen is discussed in detail.

Animals↗