[Optimization of fermentation conditions for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with Alcaligenes eutrophus]

A close relationship, between the initial addition time and concentration of propionate and HV fraction, was observed in shaking culture of Alcaligenes eutrophus for the production of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The optimal initial addition time of propionate was determined at the onset of PHBV formation period. Although relatively high HV unit could be obtained under high propionate concentration, the growth and product synthetic activities were inhibited obviously. Different ratios of glucose to propionate were fed to stimulate the formation of HV unit and the results were compared. The optimizing feeding strategy of propionate was proposed based on the consideration of several fermentation index. The final cell dry weight, PHB concentration, PHB content and HV fraction in PHBV reached 52.1 g/L, 40.8 g/L, 78.3% and 16.2 mol%, respectively, Yield coefficient of HV unit to propionate and PHBV productivity were obtained to be 0.5 g/g and 0.74 g/(L/h), respectively.

[Neuronavigation for the resection of intracranial cavernous angiomas]

OBJECTIVE

To evaluate the use of the Stealth Station neuronavigator in conjunction with preoperative computerized tomography (CT) in the resection of intracranial cavernous angiomas (CAs).

METHODS

The Stealth Station neuronavigator was used to provide real-time correlation of the operating field and computerized images in 6 patients with CAs. All of them suffered from epileptic seizures.

RESULTS

Neuronavigation-guided lesionectomy with removal of hemosiderin deposition, gliosis and calcification in all cases was performed precisely. Mean fiducial error, predicted accuracy at 10 cm, and sustained accuracy ranged from 1.65 to 4.53 mm, 1.82 to 3.28 mm, and 0.50 to 3.45 mm, respectively.

CONCLUSIONS

The Stealth Station neuronavigator is reliable and accurate in the resection of CAs.

Generation of superoxide anion by mitochondria and impairment of their functions during anoxia and reoxygenation in vitro

A small portion of the oxygen consumed by aerobic cells is converted to superoxide anion at the level of the mitochondrial respiratory chain. If produced in excess, this harmful radical is considered to impair cellular structures and functions. Damage at the level of mitochondria have been reported after ischemia and reperfusion of organs. However, the complexity of the in vivo system prevents from understanding and describing precise mechanisms and locations of mitochondrial impairment. An in vitro model of isolated-mitochondria anoxia-reoxygenation is used to investigate superoxide anion generation together with specific damage at the level of mitochondrial oxidative phosphorylation. Superoxide anion is detected by electron paramagnetic resonance spin trapping with POBN-ethanol. Mitochondrial respiratory parameters are calculated from oxygen consumption traces recorded with a Clark electrode. Respiring mitochondria produce superoxide anion in unstressed conditions, however, the production is raised during postanoxic reoxygenation. Several respiratory parameters are impaired after reoxygenation, as shown by decreases of phosphorylating and uncoupled respiration rates and of ADP/O ratio and by increase of resting respiration. Partial protection of mitochondrial function by POBN suggests that functional damage is related and secondary to superoxide anion production by the mitochondria in vitro.

[Clinical effect of tianma-cuzhi granules on senile vascular dementia]

OBJECTIVE

To assess the clinical efficacy of Tianma-cuzhi Granules (TMC) in treating senile vascular dementia(VaD) of the "sthenia of liver-yang" type.

METHOD

TMC were given to thirty VaD patients three times a day of 0.5 g/bageach. The treatment course was one month and the patients finished two consecutive courses.

RESULTS

TMC could markedly increase the mini-mental state examination (MMSE) and Hamilton depression scale(HDS) marks of VaD patients, and also contribute to improving certain indexes especially in abnormal cases.

CONCLUSION

TMC have certain effects on senile VaD.

[Expression of standard and variant CD44 in human lung cancer]

OBJECTIVE

CD44 transmembrane glycoprotein, a cell adhesion molecule, is expressed in most adult tissues and in the majority of neoplasms. Due to alternative splicing, this cell adhesion molecule exists in multiple isoforms, some of which have been associated with specific types of tumors as well as with tumor invasion and metastasis. In this study, we observed the expression of CD44 standard (CD44s) and variant forms (CD44v6) in 96 primary lung carcinomas and 12 cases of metastatic lymph nodes by immunohistochemistry and associated the results with clinical outcome. To understand the correlation of CD44's expression with the histological types, differentiation, progression and metastasis of primary lung carcinomas.

METHOD

Formalin-fixed paraffin-embedded archival tissues from 56 squamous cell carcinomas (SCC), 34 adenocarcinomas (ADC), 6 small cell lung carcinomas (SCLC) and 12 metastatic lymph nodes were immunostained after microwave antigen repair with monoclonal antibodies against CD44s and CD44v6, and the results were associated with histological tumor type, tumor stage and metastasis.

RESULT

(1) SCC showed much higher membranous expression of CD44s and CD44v6 than ADC (P < 0.01), and there is no expression in all 6 SCLC cases. (2) In 12 metastatic lymph nodes, 10 metastatic lung carcinomas were found strong immunoreactivity for CD44v6 (83%), and in comparison with lung carcinomas without lymph node metastasis (51%), primary lung carcinomas with lymph node metastasis showed strong expression of CD44v6 (91%, chi 2 = 14.92, P < 0.01). (3) The expression of CD44s and CD44v6 is independent from tumor histopathological grading (well, moderate, poor differentiated). Among different tumor stages, however, there is a distinct statistic difference between stage I + II and stage III + IV (chi 2 = 6.05, P < 0.05) with the tendency of higher stage with higher expression of CD44v6.

CONCLUSION

CD44 expresses mostly in NSCLC. Moreover, there is an stronger expression of CD44s and v6 in SCC over ADC; Immunopositivity of CD44v6 may suggest a potential of high risk for lymph node metastasis in NSCLC; CD44v6 reactivity may be useful to decide TNM stage of NSCLC, especially to discriminate stage I, II with higher stage.

Mechanism of mammalian soluble epoxide hydrolase inhibition by chalcone oxide derivatives

A series of substituted chalcone oxides (1,3-diphenyl-2-oxiranyl propanones) and structural analogs was synthesized to investigate the mechanism by which they inhibit soluble epoxide hydrolases (sEH). The inhibitor potency and inhibition kinetics were evaluated using both murine and human recombinant sEH. Inhibition kinetics were well described by the kinetic models of A. R. Main (1982, in Introduction to Biochemical Toxicology, pp. 193-223, Elsevier, New York) supporting the formation of a covalent enzyme-inhibitor intermediate with a half-life inversely proportional to inhibitor potency. Structure-activity relationships describe active-site steric constraints and support a mechanism of inhibition consistent with the electronic stabilization of the covalent enzyme-inhibitor intermediate. The electronic effects induced by altering the ketone functionality and the para-substitution of the phenyl attached to the epoxy C1 (i.e., the alpha-carbon) had the greatest influence on inhibitor potency. The direction of the observed influence was reversed for the inhibitory potency of glycidol (1-phenyl-2-oxiranylpropanol) derivatives. Recent insights into the mechanism of epoxide hydrolase activity are combined with these experimental results to support a proposed mechanism of sEH inhibition by chalcone oxides.

[Determination of content of radix Paeoniae Rubar(Chishao)801 in rabbit's plasma by HPLC]

A HPLC method was used to determine the content of Radix Paeoniae Rubar (Chishao)801 in rabbit's plasma, using Nucleosil C18 column, methanol, water and glacial acetic acid (48:50:2) as mobile phase ethye 4-hydroxybenzoate as internal standard, and UV-detector(lambda max: 275 nm, AUFS: 0.02). The average recovery was 96.70%(C: 2.5 micrograms/ml) and 98.86%(C: 5 micrograms/ml) respectively. The lowest determination limit was 0.1 microgram/ml. The method is simple, accurate, sensitive and reliable.

[Protective effect of Astragalus membranaceus (Fisch.) Bge. and Hedysarum polybotrys Hand.-Mazz. on experimental model of cerebral ischemia in rats]

The experimental model of middle cerebral artery embolism in rats was made by inserting nylon thread. It was discovered that Astragalus membranaceus decoction(both 4.26 g.kg-1 and 7.1 g.kg-1) could reduce the capillary hyperpermeability and alleviate the dyskinesia caused by cerebral ischemia in rats. Purified Hedysarum polybotrys decoction (waste substances removed with alcohol after decocting with water) (12.5 g.kg-1) could reduce the water content in brain caused by occlusion of bilateral carotids in rats. Purified Hedysarum polybotrys decoction showed a tendency to reduce the water content in brain, but without statistical significance.

Protective effects of salvianolic acid A against impairment of memory induced by cerebral ischemia-reperfusion in mice

OBJECTIVE

To investigate the protective effects of Salvianolic acid A against impairment of memory induced by cerebral ischemia-reperfusion in mice and the relationship between antioxidant activity of salvianolic acid A and its protective effects on brain injury caused by reperfusion.

METHODS

Step down and step through tests were used to examine the function of memory in the model of impairment of memory induced by cerebral ischemia-reperfusion in mice.

RESULTS

Salvianolic acid A (Sal A) at the dosage of 3 and 10 mg.kg-1 i.v. could improve the impaired memory function induced by cerebral ischemia-reperfusion as shown in step down and step through tests. In step down tests, the mean number of errors of Sal A 3 and 10 mg.kg-1 treated group were 1.29, 1.15 and that of control group was 3.8 (P < 0.01). The latencies of these tests were longer than those of the control group. Meanwhile, 3 and 10 mg.kg of Sal A i.v. were found to reduce the malondialdehyde contents in the cortex, hippocampus and corpus striatum of cerebral ischemia-reperfusion rat in vivo. Sal A 10-100 nmol.L-1 was also shown to inhibit lipid-peroxidation of the brain and scavenge the free hydroxyl radicals in vitro.

CONCLUSION

These indicate that the ameliorating effect of Sal A on learning and memory impairment caused by cerebral ischemia reperfusion may be related to its anti-oxidant activity.

How is pheromone specificity encoded in proteins?

Pheromone specificity in the Lepidoptera is encoded in protein components of the antennal sensillum lymph and dendritic membrane. In this paper, we highlight recent work on the molecular determinants of pheromone binding affinity of pheromone binding proteins (PBPs) of three genera. First, we describe new cDNA sequences for Lymantria dispar (Lymantriidae) and Agrotis segetum (Noctuidae). These data enrich the conclusions derived from our functional studies. Secondly, we indicate how preparation of multimilligram quantities of the recombinant PBP 'Apol-3' (originally from Antheraea polyphemus) has provided a platform (i) to determine the ligand binding sites using photoaffinity labeling, (ii) to conduct structural analysis by CD and NMR, and (iii) to measure binding affinities using a new binding assay. Thirdly, we describe the use of expression-cassette PCR technology to prepare two related PBPs from Antheraea perneyi to test binding affinities of naturally-occurring homologous PBPs. Our results support a model in which ligand specificity for chain length, double bond position, and terminal functionality is partially encoded in the PBPs. We propose that the final decoding is accomplished when the PBP-pheromone complex activates a G-protein coupled seven-transmembrane domain receptor that contains recognition sites for both the presented pheromone and the presenting PBP.

Protein structure encodes the ligand binding specificity in pheromone binding proteins

The ligand specificities and binding affinities of three recombinant pheromone binding proteins (PBPs) of two saturniid moths (genus Antheraea) were determined by using a novel binding assay in conjunction with two tritium-labeled constituents of the pheromone blend, [3H]-6E,11Z-hexadecadienyl acetate and [3H]-4E,9Z-tetradecadienyl acetate. The new binding assay, in which nonspecific adsorption to a plastic vessel is suppressed by presaturation of the surface with a 1-alkanol, allows measurement of dissociation constants (KD) for lipophilic ligands for their carrier proteins. The three PBPs showed KD values for [3H]-6E,11Z-16:Ac and [3H]-4E,9Z-14:Ac between 0.6 and 30 microM, as determined by Scatchard analysis. Importantly, two PBPs (Aper-1 and Aper-2) from one species showed opposite binding specificities for these two ligands. Aper-1, like Apol-3, showed 15-fold higher affinity for 6E,11Z-16:Ac than for 4E,9Z-14:Ac, while Aper-2 showed a 3.5-fold preference for binding the shorter chain compound. In addition, for the Apol-3 PBP, displacement of [3H]-6E,11Z-16:Ac binding by other pheromone components or analogs showed a clear trend in relative binding affinity: 6E,11Z-16:Ac > 4E,9Z-14:Ac > 6E,11Z-16:Al approximately 16:Ac > 6E,11Z-16:OH > 4E,9Z-14:OH. These data clearly demonstrate a > 1000-fold range of binding affinities among these very similar structures and unambiguously demonstrate the specificity of the PBP-pheromone interaction. Moreover, this assay offers the potential for determining ligand specificities for odorant binding proteins and other proteins in the vertebrate lipocalin superfamily.

Gastric atrophy and regional variation in upper gastrointestinal disease

OBJECTIVE

To compare the upper gastrointestinal disease profiles of Helicobacter pylori-infected patients drawn from two distinct regions of China, one with a low incidence of gastric cancer (Guangzhou) and the other with a high incidence of gastric cancer (Lanzhou). The age-standardized prevalence of H. pylori within the populations of these two cities was similar (approximately 56%). In these patient groups, the prevalence of different gastrointestinal disease states and the occurrence and severity of gastritis, gastric atrophy, and intestinal metaplasia were compared.

METHODS

This study was based on consecutive patients: 265 from Guangzhou and 275 from Lanzhou. The grading of gastritis and the detection of H. pylori was determined by histology using the "Sydney System".

RESULTS

The ratio of cases of duodenal to gastric ulceration for the two cities was: Guangzhou 14:1 and Lanzhou 3:1. Gastric cancer was more prevalent in the patients from Lanzhou (9.8%) than from Guangzhou (3%). In nonulcer dyspepsia patients from Guangzhou, gastritis was predominantly antral, whereas, in Lanzhou, gastritis was predominantly uniform. The amount and severity of atrophy was significantly greater in Lanzhou compared with Guangzhou.

CONCLUSIONS

The prevalence of atrophy, rather than age of acquisition and prevalence of H. pylori infection, appears to be a marker of the major upper gastrointestinal disease profiles of a region. Development of atrophy, although apparently related to H. pylori infection, may be a multifactorial condition. Differences in diet, as seen between Guangzhou and Lanzhou, may be important in this regard. Understanding the factors leading to the development of atrophy may enhance our understanding of processes leading to gastric malignancy.

Nonlinear behavior of a liquid containing uniform bubbles: comparison between theory and experiments

Bubbles oscillating at resonance frequency dramatically enhance nonlinearity of a bubbly liquid. A second-order nonlinear wave equation taking account of bubble pulsation is solved. Numerical calculations based on the equation are compared favorably with experimental results. Possible biological significance of the highly nonlinear medium is also discussed.

[An investigation on the present situation of HCV infection patients with liver diseases and in blood recipients in Baise District of Guang Xi]

ELISA was used to detect anti-HCV antibody in 179 serum samples of patients with various types of liver diseases and 41 serum samples of blood recipients in Baise district of Guang Xi. The results showed that 17.9% of patients with various types of liver diseases and 31.7% of blood recipients were anti-HCV positive. Among patients with liver diseases, the anti-HCV positive rate was 4.3% (1/23) in acute hepatitis (AH), 12.8% (10/78) in chronic hepatitis (CH), 28.6% (12/42) in liver cirrhosis (LC) and 25.0% (9/36) in hepatocellular carcinoma (HCC). As liver diseases became chronic, the anti-HCV positive rate tended to rise. The anti-HCV positive rate in LC was significantly higher than that in AH or CH (P < 0.05). The anti-HCV positive rate in HCC was not significantly different from that in AH or CH (P > 0.05 or 0.1). It was found that the anti-HCV positive rate in HBsAg-negative patients was significantly higher than that in HBsAg-positive patients (P < 0.05). The anti-HCV positive rate in liver diseases was not related to ALT (P > 0.05). In blood recipients, the anti-HCV positive rate was closely related to the number of transfusion and the activity of ALT.

Odorant binding by a pheromone binding protein: active site mapping by photoaffinity labeling

The bacterially expressed recombinant pheromone binding protein (PBP) of Antheraea polyphemus was photoaffinity labeled with (6E,11Z)-[3H]hexadecadienyl diazoacetate, a photoactivatable analog of the naturally occurring acetate pheromone. Radiolabeled peptides were separated from an endoproteinase Lys-C digestion by HPLC and characterized by Edman degradation. The label was exclusively found in the Asp39-Lys58 fragment. Cleavage of this peptide (DDYVMTDRLAGCAINCLATK) with Arg-C gave a single radiolabeled peptide (DDYVMTDR), which was predicted to be alpha-helical. The adjoining LAGCAINCLATK fragment, which is highly conserved in PBP sequences, was predicted to be a hydrophobic beta-strand and has been proposed to be important in recognition of the alkadienyl chain. Edman degradation confirmed the location of the covalently attached ligand at Thr44 of the smaller hydrophilic peptide. In addition, the synthesis of the newly identified pheromone component (4E,9Z)-tetradecadienyl acetate and its photoaffinity analog, (4E,9Z)-[3H]tetradecadienyl diazoacetate, is also described. Mapping of PBP photoaffinity labeled by (4E,9Z)-[3H]14:Dza revealed that the hydrophobic region Asp21-Lys38 adjacent to the primary binding domain Asp39-Lys58 contained a second modification site. The 14-carbon odorant molecule thus had two binding positions within the recognition site, while only a single binding position was available to the 16-carbon pheromone.

Acoustic streaming generated by a focused Gaussian beam and finite amplitude tonebursts

Theoretical models for calculating the on-axis acoustic streaming velocity generated by a continuous-wave (CW) and pulsed finite amplitude ultrasonic beams have been developed. Using these models, the on-axis streaming velocity is calculated for unfocused linear plane wave ultrasonic beams, focused linear Gaussian beams, and unfocused ultrasonic tonebursts of finite amplitude. The numerical results show that the on-axis streaming velocity is significantly enhanced by the nonlinear harmonic generation of finite-amplitude ultrasonic tonebursts.