Chronic treatment with vascular endothelial growth factor preserves agonist-evoked vascular responses in the streptozotocin-induced diabetic rat

AIMS/HYPOTHESIS

Vascular dysfunction is a hallmark of diabetes mellitus and endothelial dysfunction is considered to be a key early component of vascular dysfunction. Attenuated agonist-evoked responses are considered to be a barometer of endothelial/vascular dysfunction. We sought to determine whether vascular endothelial growth factor (VEGF) could prevent dysfunction from developing in the streptozotocin (STZ)-induced rat model of type 1 diabetes.

MATERIALS AND METHODS

One week after induction of diabetes, STZ rats began a 4-week treatment protocol of twice-weekly i.v. injections of 2 microg VEGF or inactivated VEGF. Corresponding non-diabetic rats served as controls. Agonist-evoked vascular responses were recorded 1 day after the last treatment in anaesthetised rats.

RESULTS

Acetylcholine (0.1-12.5 microg/kg) evoked increases in superior mesenteric arterial conductance and decreases in mean blood pressure, while methoxamine (12.5-100 microg/kg) and endothelin-1 (100-1,200 pmol/kg) evoked decreases in superior mesenteric arterial conductance and increases in mean blood pressure. These responses to all three agonists were attenuated in STZ rats, and chronic treatment with VEGF improved these responses dramatically. Both the reduction in plasma nitrate and nitrite and the elevation in aortic superoxide associated with STZ diabetes were normalised with VEGF treatment. VEGF also prevented the apparent paradoxical increased endothelial nitric oxide synthase expression seen in untreated STZ rats.

CONCLUSIONS/INTERPRETATION

Chronic treatment with VEGF early in diabetes is able to prevent the attenuated agonist-evoked vascular responses in STZ rats and normalise the oxidative environment associated with the disease.

Novel tiO2 nanocatalysts for wastewater purification: tapping energy from the sun

Water treatment using TiO2 semiconductor as a durable heterogeneous photocatalyst has been the focus of environmentalists in recent years. Currently, we developed an inexpensive and highly efficient approach for synthesizing nitrogen-doped TiO2 with lower band-gap energy that can respond to visible light. Doping on the molecular scale led to an enhanced nitrogen concentration of up to 21.8%. Reflectance measurements showed the synthesized N-doped TiO2 nanoparticles are catalytically active with the absorbance that extends into the visible region up to 600 nm. The water purification potential of this new class of compound was evaluated by studying the photodegradation of Acid Orange 7 (AO7) and E. coli. Experiments were conducted to compare the photocatalytic activities of N-doped TiO2 nanocatalysts and commercially available Degussa P25 power under identical solar light exposure. N-doped TiO2 demonstrated superior photocatalytic activities in both chemical compound degradation and bactericidal reactions. The result of this study shows the potential of applying new generations of catalyst for wastewater purification and disinfection.

Activation of antitumor cytotoxic T lymphocytes by fusion of patient-derived dendritic cells with autologous osteosarcoma

BACKGROUND AND AIM

Fusion of human dendritic cells (DCs) with tumor cells is an effective approach for delivering tumor antigens to DCs, and DC/tumor fusion cells are potent stimulators of autologous T cells. However, the integration and morphology of DC/osteosarcoma fusion cells has not been examined. This study was designed to investigate the antitumor effects of tumor vaccine produced by electrofusion between human osteosarcoma cells and DCs.

METHODS

In the present study, we eletrofused patient-derived DCs to autologous osteosarcoma cells. The fusion cells possessed the properties of both patient cells. After electrofusion, the cytoplasm of the two cells was integrated, whereas their nuclei remained separate entities. The intracellular structure was observed on fusion cells under the transmission electron microscope.

RESULTS

Coculture of patient-derived peripheral blood mononuclear cells (PBMC) with DC/tumor fusion cells resulted in activation of T cells as assessed by standard cytotoxic T lymphocytes (CTLs) assays.

CONCLUSIONS

The present study provides valid evidence on integration of human DCs and tumor cells and links their properties to T cell activation. The fusion cells may thus represent a promising strategy for DC-based immunotherapy of patients with osteosarcoma.

Effects of Dry Matter Intake, Addition of Buffer, and Source of Fat on Duodenal Flow and Concentration of Conjugated Linoleic Acid and Trans-11 C18:1 in Milk

The primary objective of the study was to investigate the effects of DM intake, addition of buffer, and fish vs. soybean oil on duodenal flows and milk concentrations of conjugated linoleic acid (CLA) and trans-11 C18:1. Four ruminally and duodenally cannulated multiparous cows averaging 106 +/- 17 d in milk at the start of the trial were used in a 4 x 4 Latin square design with treatments as follows: 1) control=diet contained 2% fish oil and fed ad libitum, 2) buffer addition (BUFF)=control diet with 0.8% of NaHCO3 added, 3) low DM intake (LDMI)=DMI restricted to 80% of the control but concentration of fish oil was increased to 2.5% to provide for similar fatty acids (FA) intake, and 4) soybean oil (SBO)=same as control except 2% soybean oil was substituted for fish oil. The diets consisted of 36.2% forage and 63.8% concentrate. Each period consisted of 18 d, with the last 7 d devoted to data collection and the first 4 d used to determine the appropriate amount of feed to be offered to the cow on LDMI. Duodenal flows of CLA and trans-C18:1 were lower for SBO than for diets with fish oil. Feeding buffer did not affect ruminal pH or duodenal flows of trans-11 C18:1 and CLA. Restriction of DMI decreased duodenal flow of trans-11 C18:1 but did not decrease duodenal flow of CLA compared with control. In milk, CLA concentration was lower for SBO (24.5, 17.9, 18.5, and 10.1 mg/g of FA for control, BUFF, LDMI, and SBO, respectively). Cows fed fish oil had higher duodenal flow and milk concentration of n-3 polyunsaturated fatty acids than the cows fed SBO. Compared with SBO, fish oil is more effective in increasing duodenal flows of CLA and trans-11 C18:1, and thus, concentration of CLA in milk.

Effects of Substrate, Passage Rate, and pH in Continuous Culture on Flows of Conjugated Linoleic Acid and Trans C18:1

A dual-flow continuous culture system consisting of 4 fermenters was used in a 4 x4 Latin square design. The objective of the research was to evaluate the effects of solid dilution rate (SDR), pH, and concentration of linoleic acid (LA) in the feed mixture on the production of conjugated linoleic acid (CLA) and trans-C18:1. The 4 treatments were 1) control = pH 6.5, 1% LA, 4%/h SDR; 2) high solid dilution rate (HSDR) = pH 6.5, 1% LA, 8%/h SDR; 3) high linoleic acid (HLA) = pH 6.5, 3% LA, 4%/h SDR; and 4) low pH (LPH) = pH 5.8, 1% LA, 4%/h SDR. Inoculum was collected 6 h after feeding from a cow fed 40% alfalfa hay and 60% grain. Liquid dilution rate was held at 0.12/h. All treatments except HLA contained 2% tallow. The LA was dissolved in buffer and continuously infused into the fermenters. The CLA flows were 16.5, 20.4, 23.2, and 25.2 mg/d for control, HSDR, HLA, and LPH, respectively. Compared with control, LPH increased flows of CLA, cis-C18:1, and C18:2, and decreased flow of C18:0. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibilities were not affected by pH. The HSDR tended to increase CLA flow compared to control, possibly because a shorter solid retention time led to incomplete biohydrogenation (BH). The NDF and ADF digestibilities and bacterial numbers were reduced by HSDR. With more LA available as a substrate for CLA, HLA resulted in a higher flow of CLA than control. The HLA resulted in the highest acid detergent fiber and fatty acid digestibilities, bacterial numbers, and BH. Increasing solids passage rate, reducing pH, and increasing dietary LA appears to increase in vitro CLA production.

Effects of Corn Silage Hybrid and Dietary Concentration of Forage NDF on Digestibility and Performance by Dairy Cows

Eight intact multiparous cows and four ruminally and duodenally cannulated primiparous cows were fed four diets in a replicated 4 x 4 Latin square design: 1) 17% forage neutral detergent fiber (NDF) with brown midrib corn silage (BMRCS), 2) 21% forage NDF with BMRCS, 3) 17% forage NDF with conventional corn silage (CCS), and 4) 21% forage NDF with CCS. Diets contained 17.4% crude protein and 38.5% NDF. Each period consisted of 4 wk for intact cows and 2 wk for cannulated cows. For intact cows, DM intake was higher for BMRCS than CCS, and milk urea N was higher for 21 than 17% forage NDF. Milk protein yield tended to be higher and milk urea N lower for cows fed BMRCS than those fed CCS. Milk yield and milk protein percentage were similar among treatments. For the cannulated cows, ruminal mat consistency was similar among treatments. Based on a 72 h in situ incubation, BMRCS was lower in indigestible NDF than CCS. The BMRCS resulted in a higher proportion of ruminal propionate than CCS. Cows fed 21% forage NDF had a higher proportion of acetate and a lower proportion of propionate than cows fed 17% forage NDF. The total tract digestibility of nutrients and efficiency of bacterial N synthesis were similar among treatments, except that BMRCS resulted in lower intestinal fatty acid digestibility than CCS, and 17% forage NDF tended to result in higher total tract fatty acid digestibility than 21% forage NDF. Ruminal NDF digestibility was similar among dietary treatments. The increased milk production observed from feeding BMRCS in some studies may be explained by higher DM intake rather than increased total tract digestibility of the diets.

Evolution of an organophosphate-degrading enzyme: a comparison of natural and directed evolution

Organophosphate-degrading enzyme from Agrobacterium radiobacter P230 (OPDA) is a recently discovered enzyme that degrades a broad range of organophosphates. It is very similar to OPH first isolated from Pseudomonas diminuta MG. Despite a high level of sequence identity, OPH and OPDA exhibit different substrate specificities. We report here the structure of OPDA and identify regions of the protein that are likely to give it a preference for substrates that have shorter alkyl substituents. Directed evolution was used to evolve a series of OPH mutants that had activities similar to those of OPDA. Mutants were selected for on the basis of their ability to degrade a number of substrates. The mutations tended to cluster in particular regions of the protein and in most cases, these regions were where OPH and OPDA had significant differences in their sequences.

The photoreceptor localization confirms the spectral heterogeneity of ommatidia in the male small white butterfly, Pieris rapae crucivora

The compound eye of Pieris rapae crucivora contains ventrally three types of histologically distinct ommatidia. An ommatidium contains nine photoreceptors, four of which (R1-4) construct the distal tier of the rhabdom. We determined the sensitivity spectra of the R1-4 distal photoreceptors in each type of ommatidia by intracellular electrophysiology and identified UV, blue, double-peaked blue, green, and a green receptor with depressed sensitivity in the violet. We localized these receptors in each type of ommatidia by injecting dye after the recording. In type I ommatidia the R1 and R2 cells are UV and blue receptors. When R1 is UV sensitive, R2 is always blue sensitive, or vice versa. R3 and R4 in type I are both green receptors. In type II, R1 and R2 are both double-peaked blue receptors and R3 and R4 are both green receptors with depressed sensitivity in the violet. In type III, R1 and R2 are both UV, and R3 and R4 are green receptors. The double-peaked blue, and green receptors with depressed sensitivity in the violet in type II ommatidia have depressed sensitivity at 420 nm, which is probably due to the filtering effect of a fluorescing material present in the type II ommatidia. Spectral heterogeneity of ommatidia seems to be a common design of insect compound eyes.

[Differentiated microcarcinoma of the thyroid gland in 45 cases]

OBJECTIVE

To offer therapeutic management for patients with microcarcinoma of the thyroid gland (TMC).

METHOD

Forty-five patients with TMC were treated from 1993, including 10 males and 35 females. Homolateral total thyroidectomy + contralateral subtotal thyroidectomy + homolateral functional neck dissection was taken as routine.

RESULT

Among 168 patients with differentiated carcinoma of the thyroid gland, 45 patients were TMC (26.78%). Homolateral metastasis of lymph node presented in 11 (24.44%) of the TMC patients. No operation complications. All patients were followed up. No recurrence, no death.

CONCLUSION

The lymph node metastasis appears to be high. Homolateral total thyroidectomy + contralateral subtotal thyroidectomy + homolateral functional neck dissection was effective and essential.

Changes in serum leptin levels in chronic renal failure patients with metabolic acidosis

OBJECTIVE

To examine the relationship between serum leptin levels (SLL) and metabolic acidosis in patients with chronic renal failure (CRF).

DESIGN

SLL in control patients and in predialysis patients with CRF were measured and compared. SLL before and after correction of acidosis in patients with CRF were also compared.

PATIENTS AND CONTROLS

Twenty-five patients with CRF (10 men and 15 women) aged 51.2 +/- 10.4 years and control patients (healthy subjects, 23 men and 25 women) aged 42.1 +/- 12.6 years were studied.

INTERVENTION

Five percent sodium bicarbonate (NaHCO(3), 2 to 3 mL/kg) was intravenously infused on the morning of the first day of treatment. NaHCO(3) was taken orally at a dosage of 50 to 200 mg/kg/d for 3 to 5 days thereafter.

MAIN OUTCOME MEASURE

SLL before and after NaHCO(3) treatment was measured by radioimmunoassay, and blood gas was measured before and after correction of metabolic acidosis in patients with CRF.

RESULTS

SLL in the normal control group (n = 48) was 10.04 +/- 7.0 ng/mL and was realated to body mass index (BMI) (P =.0331). SLL in men (n = 23) was lower than that in female controls (n = 25, P <.01). SLL in patients with CRF (n = 25) before (plasma HCO(3)(-), 13.03 +/- 3.05 mmol/L) and immediately after improvement of metabolic acidosis (plasma HCO(3)(-), 18.35 +/- 4.21 mmol/L) was 14.52 +/- 9.27 ng/mL and 15.34 +/- 11.89 ng/mL (P >.05), respectively. SLL measured 3 to 5 days after treatment for metabolic acidosis (plasma HCO(3)(-), 20.46 +/- 4.03 mmol/L) was 19.33 +/- 14.58 ng/mL, which was significantly higher than that in the normal control group and that in acidotic patients before NaHCO(3) treatment (P <.01).

CONCLUSIONS

SLL in acidotic patients with CRF were comparable to that in control subjects, and SLL was significantly increased after correction of metabolic acidosis in patients with CRF. The preliminary results suggest that hyperleptinemia in patients with CRF may be masked by metabolic acidosis and that metabolic acidosis may inhibit leptin synthesis or secretion. Further studies are needed to clarify the mechanisms.

Crystal structure of Staphylococcus aureus tyrosyl-tRNA synthetase in complex with a class of potent and specific inhibitors

SB-219383 and its analogues are a class of potent and specific inhibitors of bacterial tyrosyl-tRNA synthetases. Crystal structures of these inhibitors have been solved in complex with the tyrosyl-tRNA synthetase from Staphylococcus aureus, the bacterium that is largely responsible for hospital-acquired infections. The full-length enzyme yielded crystals that diffracted to 2.8 A resolution, but a truncated version of the enzyme allowed the resolution to be extended to 2.2 A. These inhibitors not only occupy the known substrate binding sites in unique ways, but also reveal a butyl binding pocket. It was reported that the Bacillus stearothermophilus TyrRS T51P mutant has much increased catalytic activity. The S. aureus enzyme happens to have a proline at position 51. Therefore, our structures may contribute to the understanding of the catalytic mechanism and provide the structural basis for designing novel antimicrobial agents.

Simultaneous recovery of RNA and DNA from soils and sediments

Recovery of mRNA from environmental samples for measurement of in situ metabolic activities is a significant challenge. A robust, simple, rapid, and effective method was developed for simultaneous recovery of both RNA and DNA from soils of diverse composition by adapting our previous grinding-based cell lysis method (Zhou et al., Appl. Environ. Microbiol. 62:316-322, 1996) for DNA extraction. One of the key differences is that the samples are ground in a denaturing solution at a temperature below 0 degrees C to inactivate nuclease activity. Two different methods were evaluated for separating RNA from DNA. Among the methods examined for RNA purification, anion exchange resin gave the best results in terms of RNA integrity, yield, and purity. With the optimized protocol, intact RNA and high-molecular-weight DNA were simultaneously recovered from 19 soil and stream sediment samples of diverse composition. The RNA yield from these samples ranged from 1.4 to 56 microg g of soil(-1) dry weight), whereas the DNA yield ranged from 23 to 435 microg g(-1). In addition, studies with the same soil sample showed that the DNA yield was, on average, 40% higher than that in our previous procedure and 68% higher than that in a commercial bead milling method. For the majority of the samples, the DNA and RNA recovered were of sufficient purity for nuclease digestion, microarray hybridization, and PCR or reverse transcription-PCR amplification.

Inhibitors of bacterial enoyl acyl carrier protein reductase (FabI): 2,9-disubstituted 1,2,3,4-tetrahydropyrido[3,4-b]indoles as potential antibacterial agents

An SAR study of a screening lead has led to the identification of 2,9-disubstituted 1,2,3,4-tetrahydropyrido[3,4-b]indoles as inhibitors of Staphylococcus aureus enoyl acyl carrier protein reductase (FabI).

Seven human immunodeficiency virus (HIV) antigen-antibody combination assays: evaluation of HIV seroconversion sensitivity and subtype detection

In this study, we evaluated the performance of two prototype human immunodeficiency virus (HIV) antigen-antibody (Ag-Ab) combination assays, one from Abbott Laboratories (AxSYM HIV Ag-Ab) and the other from bioMerieux (VIDAS HIV Duo Ultra), versus five combination assays commercially available in Europe. The assays were Enzygnost HIV Integral, Genscreen Plus HIV Ag-Ab, Murex HIV Ag-Ab Combination, VIDAS HIV Duo, and Vironostika HIV Uniform II Ag-Ab. All assays were evaluated for the ability to detect p24 antigen from HIV-1 groups M and O, antibody-positive plasma samples from HIV-1 groups M and O, HIV-2, and 19 HIV seroconversion panels. Results indicate that although all combination assays can detect antibodies to HIV-1, group M, subtypes A to G, circulating recombinant form (CRF) A/E, and HIV-1 group O, their sensitivity varied considerably when tested using diluted HIV-1 group O and HIV-2 antibody-positive samples. Among combination assays, the AxSYM, Murex, and VIDAS HIV Duo Ultra assays exhibited the best antigen sensitivity (at approximately 25 pg of HIV Ag/ml) for detection of HIV-1 group M, subtypes A to G and CRF A/E, and HIV-1 group O isolates. However, the VIDAS HIV Duo Ultra assay had a lower sensitivity for HIV-1 group M and subtype C, and was unable to detect subtype C antigen even at 125 pg of HIV Ag/ml. The HIV antigen sensitivity of the VIDAS HIV Duo and Genscreen Plus combination assays was approximately 125 pg of HIV Ag/ml for detection of all HIV-1 group M isolates except HIV-1 group O while the sensitivity of Vironostika HIV Uniform II Ag-Ab and Enzygnost HIV Integral Ag-Ab assays for all the group M subtypes was >125 pg of HIV Ag/ml. Among the combination assays, the AxSYM assay had the best performance for detection of early seroconversion samples, followed by the Murex and VIDAS HIV Duo Ultra assays.

[Study on the quality standards for xianghe suppository]

The quality standards for Xianghe suppository were studied. The TLC methods for identification of Rhizoma Coptidis, Radix Sophorae Flavescentis and Flos Caryophylli were established. A simple high performance liquid chromatographic method was established for determination of berberine and palmatine. The mobile phase was acetonitrile-water(1:1, containing KH2PO4 3.4 g, CH3(CH2)11 SO4Na 1.7 g per 1000 ml). UV detecting wavelength was 345 nm. This method is suitable for the quality control of Xianghe suppository.

Identification of a Delta 4 fatty acid desaturase from Thraustochytrium sp. involved in the biosynthesis of docosahexanoic acid by heterologous expression in Saccharomyces cerevisiae and Brassica juncea

The existence of Delta 4 fatty acid desaturation in the biosynthesis of docosahexanoic acid (DHA) has been questioned over the years. In this report we describe the identification from Thraustochytrium sp. of two cDNAs, Fad4 and Fad5, coding for Delta 4 and Delta 5 fatty acid desaturases, respectively. The Delta 4 desaturase, when expressed in Saccharomyces cerevisiae, introduced a double bond at position 4 of 22:5(n-3) and 22:4(n-6) resulting in the production of DHA and docosapentanoic acid. The enzyme, when expressed in Brassica juncea under the control of a constitutive promoter, desaturated the exogenously supplied substrate 22:5(n-3), resulting in the production of DHA in vegetative tissues. These results support the notion that DHA can be synthesized via Delta 4 desaturation and suggest the possibility that DHA can be produced in oilseed crops on a large scale.

1,4-Disubstituted imidazoles are potential antibacterial agents functioning as inhibitors of enoyl acyl carrier protein reductase (FabI)

1,4-Disubstituted imidazole inhibitors of Staphylococcus aureus and Escherichia coli enoyl acyl carrier protein reductase (FabI) have been identified. Crystal structure data shows the inhibitor 1 bound in the enzyme active site of E. coli FabI.

Dynamic process of apoptosis in adult rat cardiomyocytes analyzed using 48-hour videomicroscopy and electron microscopy: beating and rate are associated with the apoptotic process

Dynamic process of apoptosis has not been elucidated in adult rat cardiomyocytes. Soluble Fas ligand (0.1 microg/ml) in the presence of actinomycin D (0.05 microg/ml) induced apoptosis in cultured adult rat cardiomyocytes, as documented by activated caspase-3, DNA fragmentation, and apoptotic ultrastructure. In the present model, we observed 60 adult cardiomyocytes with a normal rod shape under a real-time videomicroscope continuously for 48 hours. Seventeen cells (28%) were unchanged and 7 cells (12%) showed oncosis (so-called necrosis) in which no beating was evident. In the remaining 36 cells (apoptosis, 60%), a slow beating (17 +/- 3/min) was initiated 16 +/- 1 hours later. Approximately 1 hour later, the rod cells showed long-axial shortening as bone- or club-like, or square-shaped, accompanied with faster beating rates (35 +/- 7/min). In 29 cells (type A1 and A2), marked shrinkage occurred; the cellular shape became almost completely round with a smooth surface and the beating ceased 3.0 +/- 0.4 hours later. Then, smooth budding appeared 0.6 +/- 0.2 hours later. Apoptotic bodies were found in 8 cells 10 +/- 4 hours later (type A1, 13%) but not in 21 cells (type A2, 35%). In the other 7 cells (type A3, 12%), the cell surface became rough 8 +/- 3 hours later and the beating ceased. Maximal beating rate was greatest in type A1 (72 +/- 26/min) and greater in type A2 (29 +/- 5/min) than in type A3 (10 +/- 2/min). Electron microscopy confirmed apoptotic ultrastructure even in the cardiomyocytes with bone-, club-like, or square shapes, suggesting that type A3 as well as A1 and A2 is also under apoptotic process. A caspase inhibitor, zVAD.fmk, blocked beating, apoptotic morphology, and DNA fragmentation, indicating these depended on caspase activation. In the caspase-dependent apoptotic process of cultured adult cardiomyocytes, beating and the following deformity of the cellular edges were the initial signs and the rate of beating was related with the subsequent three different processes of apoptosis.

Carboxyl-methylation of Rab3D in the rat pancreatic acinar tumor cell line AR42J

Rab3D is a small GTPase implicated in regulated exocytosis, and is a marker of secretory granules in exocrine cells. We have previously shown that rab3D undergoes reversible carboxyl-methylation in adult rat pancreatic acinar cells, and that carboxyl-methylation of rab3D is developmentally regulated concomitantly with the maturation of the regulated secretory apparatus in rat pancreas. We also observed that dexamethasone treatment of the rat pancreatic acinar tumor cell line, AR42J, led to a significant increase in the size of the unmethylated pool of a rab3-like protein. The current study was designed to further characterize this rab3-like protein. Here we show that AR42J cells express rab3D, and that the protein focuses on 2D gels as two spots with pI values of 4.9 and 5.0. Treatment of AR42J cells with N-acetyl-S-geranylgeranyl-l-cysteine, an inhibitor of carboxyl-methylation, led to a decrease in the basic form of rab3D and a proportional increase in the acidic form. In contrast, N-acetyl-S-farnesyl-l-cysteine, which inhibits carboxyl-methylation of farnesylated proteins, had no effect. Lovastatin, an inhibitor of geranylgeranylation, also induced an accumulation of the acidic form of rab3D. Taken together, these data indicate that rab3D can undergo reversible carboxyl-methylation in AR42J cells by a geranylgeranyl-specific methyltransferase. The 2D gel and immunoblotting analyses indicated that dexamethasone treatment of AR42J cells led to an increase in the proportion of the unmethylated form of rab3D concurrent to inducing a regulated secretory pathway, similar to the rab3D profile change in developing rat pancreas. Our data, along with previous studies done on developing rat pancreas, indicate that the tumor cell line AR42J represents a good model system for studying the regulated secretory pathway, and that carboxyl-methylation of rab3D may play a role in the acquisition of stimulus-secretion coupling.

[Effects of processing on antioxidation of Radix et Rhizoma Rhei and Rhizoma Polygoni Cuspidati]

OBJECTIVE

To investigate the effects of Processing on antioxidation of Radix et Rhizoma Rhei and Rhizoma Polygoni Cuspidati.

METHOD

The oxygen free radicals generation system and mouse liver homogenate lipid peroxidation in vitro were used.

RESULT

The processed products of Radix et Rhizoma Rhei and Rhizoma Polygoni Cuspidati could scavenge superoxide radical (O2-.) generated through hypoxanthine-oxidase system and (.OH) generated through Fenton action, and inhibit lipid peroxidation induced by hydroxyl radical generation system, respectively. There existed significant differences among the different processed products.

CONCLUSION

After Radix et Rhizoma Rhei and Rhizoma Polygoni Cuspidati were processed, their effects became weaker.

A study of time-domain FXLMS algorithms with control output constraint

A single input, single output active noise control system using the time-domain Filtered-X LMS algorithm with output constraint is investigated. The constraint on the output of the control filter is applied by three different methods: the leakage algorithm based on the transformation method using a penalty function; the re-scaling algorithm based on the active set method; and the simple practical (clipping) algorithm which just clips the output if a constraint is encountered. A comparison of the three algorithms shows that the re-scaling algorithm can usually work successfully under the constraint, while the leakage algorithm usually needs a large leakage coefficient to satisfy the constraint with a resulting performance loss. The clipping algorithm has potential problems both with the stability and convergence speed.

Gallic acid induces vascular smooth muscle cell death via hydroxyl radical production

In the present study, we investigated whether gallic acid (GA) can induce death in cultured vascular smooth muscle cells (VSMCs), and whether production of the hydroxyl radical (.OH) is involved in the process of GA action. GA killed cultured VSMCs from rat aorta, in a dosc- and time-dependent manner. Cytoplasmic shrinkage and nuclear condensation were observed light microscopically in GA-treated VSMCs, which appeared apoptotic. However, the ultrastructure of the VSMC was not typical of apoptosis: nuclear condensation was not glossy, and the plasma membrane and subccellular organelles were disrupted. Although the VSMC were positive for in situ nick end-labeling (TUNEL). they did not show a DNA ladder pattern on gel electrophoresis and were negative for T aq polymerase-based in situ ligation, which is more specific for apoptosis than TUNEL. Moreover. GA-induced cell death was not prevented by Boc-Asp-fmk (a pan-caspase inhibitor). Production of OH was detected in GA-treated VSMCs using high-performance liquid chromatography with salicylic acid as a trapping agent. Lipid peroxidation was also observed. The production of .OH was inhibited by catalase (CAT) and deferoxamine (DFX), and these treatments completely rescued VSMCs from cell death. In a cell-free system, GA produced .OH in the presence of Fe2+-EDTA, which was quenched by CAT and DFX, suggesting involvement of the Haber-Weiss reaction. Oxidative stress by reactive oxygen species, .OH in particular, is one of the mechanisms of GA-induced death of VSMCs, the mode of which was different from typical apoptosis.

Refined structures of beta-ketoacyl-acyl carrier protein synthase III

beta-Ketoacyl-acyl carrier protein synthase III (FabH) is a condensing enzyme that plays central roles in fatty acid biosynthesis. Three-dimensional structures of E. coli FabH in the presence and absence of ligands have been refined to 1.46 A resolution. The structures of improved accuracy revealed detailed interactions involved in ligand binding. These structures also provided new insights into the FabH mechanism, e.g. the possible role of a water or hydroxyl anion in Cys112 deprotonation. A structure of the apo enzyme uncovered large conformational changes in the active site, exemplified by the disordering of four essential loops (84-86, 146-152, 185-217 and 305-307) and the movement of catalytic residues (Cys112 and His244). The disordering of the loops leads to greater than 50 % reduction in the FabH dimer interface, suggesting a dynamic nature for an unusually large portion of the dimer interface. The existence of a large solvent-accessible channel in the dimer interface as well as two cis-peptides (cis-Pro88 and cis-Phe308) in two of the disordered loops may explain the observed structural instabilities.

Two point mutations in mitochondrial DNA of cytochrome c oxidase coexist with normal mtDNA in a patient with Alzheimer's disease

The mitochondrial cytochrome c oxidase (CO) gene sequence was determined on a patient with Alzheimer's disease (AD). Compared to the standard Cambridge sequence to identify base changes,two missense mutations were found in the patient with AD. The mutations were a G to T transition at np 8206 and an A to T transition at np 8224. The np 8206 mutation changed a Met to an Ile and np 8224 mutation changed a Leu to a Phe. The normal bases and the mutations of mitochondrial DNA (mtDNA) coexist in the patient. Further studies will be required to demonstrate the role of the point mutations of mitochondrial DNA in the pathogenesis of Alzheimer's disease.

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.

Role of protein kinase C, K(ATP) channels and DNA fragmentation in the infarct size-reducing effects of the free radical scavenger T-0970

1. In the present study, we investigated the effect of 1-(3-tert-butyl-2-hydroxy-5-methoxyphenyl)-3-(3-pyridylmethyl) urea hydrocloride (T-0970), a novel water-soluble low-molecular weight free radical scavenger, on the generation of hydroxyl radicals in vivo and on myocardial infarct size in an in vivo model of myocardial infarction in rabbits. 2. T-0970 scavenged hydroxyl radicals generated in the myocardium during reperfusion, as assessed by using a microdialysis technique and HPLC in an in vivo model with 30 min coronary occlusion and 30 min reperfusion in rabbits. 3. Another group of rabbits was subjected to 30 min coronary occlusion and 48 h reperfusion. The control group (n = 10) was infused with saline for 190 min from 10 min before occlusion to 180 min after reperfusion. The treatment group (T-0970 group; n = 10) was injected with a bolus 2.5 mg/kg T-0970 and then infused with T-0970 for 190 min from 10 min before reperfusion to 180 min after reperfusion at a rate of 100 microg/kg per min. The T-0970 + CHE group (n = 5) was given chelerythrine (CHE; a selective inhibitor of protein kinase C (PKC); 5 mg/kg, i.v.) 10 min before the administration of T-0970. The T-0970 + 5-HD group (n = 5) was given 5-hydroxydecanoate (5-HD; an inhibitor of mitochondrial K(ATP) channels; 5 mg/kg, i.v.) 10 min before the administration of T-0970. The CHE and 5-HD groups were given CHE (5 mg/kg, i.v.) and 5-HD (5 mg/kg, i.v.) 20 min before reperfusion, respectively. After 48 h reperfusion, infarct size was measured histologically and expressed as a percentage of the area at risk (AAR). In another series of experiments, the control (n = 5) and T-0970 (n = 5) groups were killed 4 h after reperfusion following 30 min coronary occlusion and DNA fragmentation in myocytes was assessed using in situ dUTP nick end-labelling (TUNEL) at the light microscopic level. 4. Infarct size, as a percentage of AAR, in the T-0970 group was significantly reduced compared with the control group (21+/-4 vs 41+/-4%, respectively; P<0.05). This reduction of infarct size by T-0970 was abolished by pretreatment with CHE and 5-HD. Neither CHE nor 5-HD alone had any effect on infarct size. The percentage of infarcted myocytes with DNA fragmentation by TUNEL in the T-0970 group was significantly reduced compared with the number in the control group (4.0+/-1.5 vs 10.7+/-1.9%, respectively; P<0.05). 5. T-0970, a free radical scavenger, improved reperfusion injury. This effect seemed to be mediated by activation of PKC, the opening of mitochondrial K(ATP) channels and inhibition of DNA fragmentation.

[Single nucleotide polymorphism in beta2-adrenoceptor gene and the distribution in Chinese Han ethnic group]

OBJECTIVE

The study was conducted to investigate single nucleotide polymorphism(SNP) in beta2-adrenoceptor(beta2-AR) gene and the distribution of these identified SNPs in Chinese Han ethnic group.

METHODS

beta2-AR gene was sequenced to detect SNPs by fluorescent labeling automatic sequencing method in 80 unrelated samples from territory of Dabie Mountain in Anhui province.

RESULTS

A total of 8 SNPs were identified in length of 3.8 kb, including 5 SNPs in code region, 3 SNPs in regulatory region. Although the variations, -468C to G, -367T to C, -47C to T,-20T to C, +79C to G, +100G to A, +491C to T, +1098T to C have been identified in other ethnic groups, they have not been found in our study. The allele distribution of SNPs is in good unity with the Hardy-Weinberg equilibrium.

CONCLUSION

The distribution of SNPs in beta2-AR gene is not equable and the SNPs in different ethnic groups differ greatly. The allele distribution of SNPs conforms well to the Hardy-Weinberg equilibrium.

Identification and analysis of a gene from Calendula officinalis encoding a fatty acid conjugase

Two homologous cDNAs, CoFad2 and CoFac2, were isolated from a Calendula officinalis developing seed by a polymerase chain reaction-based cloning strategy. Both sequences share similarity to FAD2 desaturases and FAD2-related enzymes. In C. officinalis plants CoFad2 was expressed in all tissues tested, whereas CoFac2 expression was specific to developing seeds. Expression of CoFad2 cDNA in yeast (Saccharomyces cerevisiae) indicated it encodes a Delta12 desaturase that introduces a double bond at the 12 position of 16:1(9Z) and 18:1(9Z). Expression of CoFac2 in yeast revealed that the encoded enzyme acts as a fatty acid conjugase converting 18:2(9Z, 12Z) to calendic acid 18:3(8E, 10E, 12Z). The enzyme also has weak activity on the mono-unsaturates 16:1(9Z) and 18:1(9Z) producing compounds with the properties of 8,10 conjugated dienes.

Evaluation of PCR-generated chimeras, mutations, and heteroduplexes with 16S rRNA gene-based cloning

To evaluate PCR-generated artifacts (i.e., chimeras, mutations, and heteroduplexes) with the 16S ribosomal DNA (rDNA)-based cloning approach, a model community of four species was constructed from alpha, beta, and gamma subdivisions of the division Proteobacteria as well as gram-positive bacterium, all of which could be distinguished by HhaI restriction digestion patterns. The overall PCR artifacts were significantly different among the three Taq DNA polymerases examined: 20% for Z-Taq, with the highest processitivity; 15% for LA-Taq, with the highest fidelity and intermediate processitivity; and 7% for the conventionally used DNA polymerase, AmpliTaq. In contrast to the theoretical prediction, the frequency of chimeras for both Z-Taq (8.7%) and LA-Taq (6.2%) was higher than that for AmpliTaq (2.5%). The frequencies of chimeras and of heteroduplexes for Z-Taq were almost three times higher than those of AmpliTaq. The total PCR artifacts increased as PCR cycles and template concentrations increased and decreased as elongation time increased. Generally the frequency of chimeras was lower than that of mutations but higher than that of heteroduplexes. The total PCR artifacts as well as the frequency of heteroduplexes increased as the species diversity increased. PCR artifacts were significantly reduced by using AmpliTaq and fewer PCR cycles (fewer than 20 cycles), and the heteroduplexes could be effectively removed from PCR products prior to cloning by polyacrylamide gel purification or T7 endonuclease I digestion. Based upon these results, an optimal approach is proposed to minimize PCR artifacts in 16S rDNA-based microbial community studies.

Effects of forage neutral detergent fiber and yeast culture on performance of cows during early lactation

Sixty Holstein cows were assigned to two treatments at 21 d before calving and were group-fed a prepartum diet with or without yeast culture. After parturition, cows were individually fed one of five treatments for 140 d: 1) 21% forage neutral detergent fiber (NDF) without yeast culture, 2) 21% forage NDF with yeast culture, 3) 17% forage NDF without yeast culture, 4) 17% forage NDF with yeast culture, and 5) 25% forage NDF with yeast culture for 30 d and then switched to diet 4 for 110 d. Cows fed yeast culture prepartum were also fed yeast culture postpartum (60 g/d). A quadratic increase to 25, 21, and 17% forage NDF occurred during the first 30 d in milk (DIM) for dry matter intake, milk yield, and milk protein yield. No differences were observed for yeast culture or interaction of yeast culture and forage NDF for the first 30 DIM. Feeding 17 versus 21% forage NDF increased milk protein percentage and tended to increase dry matter intake as a percentage of body weight from 31 to 140 DIM. During this period, yeast culture tended to increase milk fat percentage and appeared to have positive effects on dry matter intake, milk yield, and milk fat yield when supplemented to diets with 21% forage NDF but not with 17% forage NDF. Feeding 17% forage NDF may be too low for the first 30 DIM but may improve animal performance after 30 DIM compared to 21% forage NDF.

Effect of diazepam on the contents of amino acids and free radical during ischemia/reperfusion injury

The protective effect and mechanism of diazepam on ischemia neurons during cerebral ischemia and reperfusion were studied. Sixty-three Wistar rats were divided randomly into nine groups: control group (n = 7), ischemia (is) groups including subgroups of is3 h, is3-h/rep1-h, is3-h/rep2-h, is3-h/rep3-h(n = 7 in each group), diazepam treated groups (10 mg/kg, i.p.), including subgroups of is3-h, is3-h/rep1-h, is3-h/rep2-h, is3-h/rep3-h (n = 7 in each group) with Zea longa's animal model of middle cerebral artery occlusion. The comparison between the ischemia group and diazepam-treated group showed that diazepam could obviously decrease the production of glutamate, asparate, MDA and increase the synthesis and release of GABA, SOD and GSH-PX. It was concluded that diazepam exerted its protective effects on neurons through complex mechanisms of regulating the synthesis and release of excitotary/inhibitory amino acids and free radicals.

[Hyperplasia of chromaffin cells in adrenocortical hyperplasia and adenoma]

OBJECTIVE

To study whether there is chromaffin cells hyperplasia in adrenocortical hyperplasia and adenoma.

METHODS

Chromaffin cells with chromogranin A were marked by immunohistochemistry method.

RESULTS

In 52 cases of adrenocortical hyperplasia and adenoma 3 were associated with eochromocyte hyperplasia and 5 with micro-pheochromocytoma. Six of the 8 cases were characterized by hypercortiso (or aldostero)-hypercatecholamine clinically.

CONCLUSIONS

Few cases of adrenocortical hyperplasia and adenoma may be associated with pheochromocytic hyperplasia and micro-pheochromocytoma, and may be characterized by symptoms of hypercortiso (or aldostero)-hypercatecholamine.

Autoantibodies to Abl and Bcr proteins

Formation of an aberrant, chimeric Bcr-Abl protein is the hallmark of Philadelphia (Ph) chromosome-positive leukemias. The Bcr-Abl protein, as well as its normal cellular counterparts--Abl and Bcr--are intracellular molecules with postulated roles in a variety of critical biologic functions. In this study, we demonstrate the existence of autoantibodies against these proteins. Plasma from 18 of 31 individuals (58%), including 14 of 20 Ph-positive CML patients (70%), two of four normal volunteers (50%), and two of seven patients with Ph-negative leukemia (29%) recognized p210Bcr-Abl when used in immunoprecipitation followed by immunoblotting experiments. In all 18 patients, plasma was able to recognize baculovirus-expressed Abl protein; in four patients, recognition of baculovirus-expressed Bcr protein was also demonstrated. These observations suggest that a humoral immune response to p210Bcr-Abl is discernible in both Ph-positive and -negative leukemias and in healthy individuals, and is most likely due to autoantibodies which recognize normal Abl and, to a lesser extent, normal Bcr proteins.

Mode and role of cell death during progression of atherosclerotic lesions in hypercholesterolemic rabbits

Two cell types, macrophages and smooth muscle cells (SMCs), play important roles in the development of atherosclerotic lesions. Both contribute to the formation of the lesions not only by their presence but also by taking in or releasing extracellular substrates during life and at death. The present study aimed to elucidate their turnover, focusing on the detailed description of the modes of death in each cell type, and the roles of their death in the progression from early into advanced atherosclerotic lesions. Ascending aortas were obtained from New Zealand white male rabbits fed a diet with 1% cholesterol for 3 months (3-M group, n= 6) and 6 months (6-M group, n = 6). They were histologically examined, and the cell death was checked by in situ nick end-labeling (TUNEL), using a Taq polymerase-based in situ ligation assay with/without combination of immunohistochemistry, electron microscopy (EM), and TUNEL at the EM level. Intimal hyperplasia and luminal stenosis advanced with increased dietary interval, and the aortic intima of the 3-M group consisted of histological types I-III atherosclerotic lesions, whereas that of the 6-M group included types III-V. Along with the progression, the cellular population decreased, but the area of fibrosis increased. The percentage area of macrophages declined (from 60% +/- 5% to 23% +/- 2%), but that of SMCs increased (from 5% +/- 1% to 10% +/- 2%). The positive cells for in situ ligation were less frequent in the 6-M group (0.05% +/- 0.01%) than in the 3-M group (0.2% +/- 0.04%), which was due to a decrease in SMCs positive for in situ ligation. The frequency of TUNEL-positive cells was higher than that of in situ ligation-positive cells in both groups, suggesting that cell death involved not only apoptosis but also oncosis. This was confirmed using EM: cell death occurred via both apoptosis and oncosis. EM-TUNEL positively labeled not only apoptotic but also some oncotic nuclei. Death of macrophages and SMCs involves both apoptosis and oncosis in the aortic intima of hypercholesterolemic rabbits. Decline in the dying rate of SMCs might be associated with the formation of SMC-rich and collagen-rich lesions in the late advanced stage of atherosclerosis, although such a cause-effect relationship is to be further confirmed.

Crystallization of Escherichia coli beta-ketoacyl-ACP synthase III and the use of a dry flash-cooling technique for data collection

beta-Ketoacyl-acyl carrier protein (ACP) synthase III (FabH) is a condensing enzyme active in the fatty-acid biosynthesis pathway of bacteria. The enzymes of this pathway provide a set of targets for the discovery of previously unknown antibiotics. FabH from Escherichia coli has been crystallized in two crystal forms using the sitting-drop vapor-diffusion technique. The first form crystallized in the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 63.1, b = 65.1, c = 166.5 A; the second form crystallized in the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 72.7, c = 99.8 A. A flash-cooling technique using no cryoprotectant was utilized in obtaining data from the second type of crystals.

[Clinical application of implanting nitinol alloy endotracheal stent in the treatment of tracheobronchial.]

BACKGROUND

To explore the clinical results of implanting expanding nitinol alloy stent in the treatment of tracheobronchial stenosis.

METHODS

The nitinol alloy endotracheal stent was put into the site of stricture of trachea or bronchus in 42 patients through an optical fibrobronchoscopy under X-ray examination. The oxygen saturation of blood (SaO2 ) and pulse rate were detected before , during and after operation respectively.

RESULTS

After implanting nitinol alloy stent , 32 patients got satisfactory response , and other 10 patients got partial response. In all patients , the diameters of the stenostic airway were increased significantly , and ventilation function improved remarkably. The postoperative SaO2 was greatly higher than the preoperative one ( P < 0. 001) . The quality of life was also improved.

CONCLUSIONS

The nitinol alloy endotracheal stent was an effictive , safe and reliable method to release tracheobronchial stenosis.

Expression, purification, and crystallization of the Escherichia coli selenomethionyl beta-ketoacyl-acyl carrier protein synthase III

Bacterial beta-ketoacyl-acyl carrier protein (ACP) synthase III (KAS III, also called FabH) catalyzes the condensation and transacylation of acetyl-CoA with malonyl-ACP. In order to understand the mode of enzyme/substrate interaction and design small molecule inhibitors, we have expressed, purified, and crystallized a selenomethionyl-derivative of E. coli KAS III. Several lines of evidence confirmed that purified selenomethionyl KAS III was homogenous, stably folded, and enzymatically active. Dynamic light scattering, size exclusion chromatography, and mass spectrometry results indicated that selenomethionyl KAS III is a noncovalent homodimer. Diffraction quality crystals of selenomethionyl KAS III/acetyl-CoA complex, which grew overnight to a size of 0.2 mm(3), belonged to the tetragonal space group P4(1)2(1)2.

Isolation and analysis of two cellulase cDNAs from Orpinomyces joyonii

Two cellulase cDNAs, celB29 and celB2, were isolated from a cDNA library derived from mRNA extracted from the anaerobic fungus, Orpinomyces joyonii strain SG4. The nucleotide sequences of celB2 and celB29 and the primary structures of the proteins encoded by these cDNAs were determined. The larger celB29 cDNA was 1966bp long and encoded a 477 amino acid polypeptide with a molecular weight of 54kDa. Analysis of the 1451bp celB2 cDNA revealed an 1164bp open reading frame coding for a 44kDa protein consisting of 388 amino acids. Both deduced proteins had a high sequence similarity in central regions containing putative catalytic domains. Primary structure analysis revealed that CelB29 contained a Thr/Pro-rich sequence that separated the N-terminal catalytic domain from a C-terminal reiterated region of unknown function. Homology analysis showed that both enzymes belong to glycosyl hydrolase family 5 and were most closely related to endoglucanases from the anaerobic fungi Neocallimastic patriciarum, Neocallimastix frontalis and Orpinomyces sp. The classification of CelB29 and CelB2 as endoglucanases was supported by enzyme assays. The cloned enzymes had high activities towards barley beta-glucan, lichenan and carboxymethylcellulose (CMC), but not Avicel, laminarin, pachyman, xylan and pullulan. In addition, CelB29 and CelB2 showed activity against p-nitrophenyl-beta-D-cellobioside (pNP-G(2)) to p-nitrophenyl-beta-D-cellopentaoside (pNP-G(5)) but not p-nitrophenyl-beta-D-glucopyranoside (pNP-G(1)) with preferential activity against p-nitrophenyl-beta-D-cellotrioside (pNP-G(3)). Based on these results, we proposed that CelB29 and CelB2 are endoglucanases with broad substrate specificities for short- and long-chain beta-1,4-glucans.

T-0162, a novel free radical scavenger, reduces myocardial infarct size in rabbits

1. We investigated the effects of 1-(3-tert-butyl-2-hydroxy-5-methoxyphenyl)-3-(3-pyridylmethyl)urea hydrochloride (T-0162), a novel low-molecular weight free radical scavenger, on the generation of superoxide anions and hydroxyl radicals in vitro and in vivo and on myocardial infarct (MI) size in an in vivo model of MI in rabbits. 2. It was found that T-0162 scavenged both superoxide anions and hydroxyl radicals in a concentration-dependent manner in vitro. 3. In an in vivo rabbit model with 30 min coronary occlusion and 30min reperfusion, T-0162 scavenged hydroxyl radicals generated in the myocardium during reperfusion. 4. Anaesthetized open-chest Japanese white male rabbits were subjected to 30 min coronary occlusion and 48 h reperfusion. The control group (n = 10) was infused with 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion. The pretreatment group (n = 10) was infused with T-0162 dissolved in 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion at a rate of 400 microg/kg per min. The post-treatment group (n = 10) was injected with an i.v. bolus of 10 mg/kg T-0162 and was then infused with 400 microg/kg per min T-0162 for 190 min from 10 min before reperfusion to 180 min after reperfusion. After 48 h reperfusion, infarct size was measured histologically and expressed as a percentage of area at risk (AAR). 5. There was no significant difference in haemodynamic parameters among the three groups throughout the experimental period. The per cent infarct size of the AAR in the T-0162 groups (24.8+/-4.3 and 30.5+/-3.9% for pre- and posttreatment groups, respectively) was significantly reduced compared with control (44.7+/-4.1%; P<0.05). There was no significant difference in the AAR among the three groups. 6. In conclusion, T-0162 reduces MI size through the inhibition of reperfusion injury.

WIM/WISE NMR studies of chain dynamics in solid polymers and blends

Wideline separation (WISE) NMR with window-less isotropic mixing (WIM) is developed as a method to study the dynamics of polymers and blends. This experiment is designed to measure the dynamics of polymers through the proton lineshapes that are correlated with the carbon chemical shifts in two-dimensional NMR experiments. If the atoms experience large amplitude fluctuations that are fast compared to the dipolar broadening, then the proton lines will be narrowed relative to rigid solids. We have modified the WISE experiment by replacing the cross polarization step with WIM to quench spin diffusion during the cross polarization so that the proton linewidths can be directly related to the chain dynamics. Two-dimensional WIM/WISE has been used to measure the main-chain and side-chain dynamics in poly(n-butyl methacrylate) and blends of polystyrene and poly(vinyl methyl ether).

Crystal structure of beta-ketoacyl-acyl carrier protein synthase III. A key condensing enzyme in bacterial fatty acid biosynthesis

Beta-ketoacyl-acyl carrier protein synthase III (FabH), the most divergent member of the family of condensing enzymes, is a key catalyst in bacterial fatty acid biosynthesis and a promising target for novel antibiotics. We report here the crystal structures of FabH determined in the presence and absence of acetyl-CoA. These structures display a fold that is common for condensing enzymes. The observed acetylation of Cys(112) proves its catalytic role and clearly defines the primer binding pocket. Modeling based on a bound CoA molecule suggests catalytic roles for His(244) and Asn(274). The structures provide the molecular basis for FabH substrate specificity and reaction mechanism and are important for structure-based design of novel antibiotics.

Study of thrombopoietin for gene therapy of thrombocytopenia

Thrombopoietin (TPO) is likely to he a potent, specific and reliable medication in the treatment of thrombocytopenia. A TPO-highly-expressed plasmid pcDNA3-TPO was constructed and a primary study was made on the expression of TPO cDNA in vitro and gene transfer study for thrombocytopenia in vivo. rhTPO showed complete and stable bioactivity by a series of indicators. High expression of TPO was detected in plasma from healthy mice or thrombocytopenia mice model receiving direct intramuscular injection of pcDNA3-TPO. And the platelet level of healthy mice peaked to 1.9-fold of baseline. Mice with CTX-induced thrombocytopenia achieved profound nadirs, acceleration of recovery, even 1.8-2.0-fold supranormal levels of peripheral platelet counts. The results offered experimental support for clinical application of gene therapy for thrombocytopenia via direct intramuscular injection of TPO cDNA.

Molecular basis for triclosan activity involves a flipping loop in the active site

The crystal structure of the Escherichia coli enoyl reductase-NAD+-triclosan complex has been determined at 2.5 A resolution. The Ile192-Ser198 loop is either disordered or in an open conformation in the previously reported structures of the enzyme. This loop adopts a closed conformation in our structure, forming van der Waals interactions with the inhibitor and hydrogen bonds with the bound NAD+ cofactor. The opening and closing of this flipping loop is likely an important factor in substrate or ligand recognition. The closed conformation of the loop appears to be a critical feature for the enhanced binding potency of triclosan, and a key component in future structure-based inhibitor design.

Interaction of tyrosyl aryl dipeptides with S. aureus tyrosyl tRNA synthetase: inhibition and crystal structure of a complex

Tyrosyl aryl dipeptide inhibitors of S. aureus tyrosyl tRNA synthetase have been identified with IC50 values down to 0.5 microM. A crystal structure of the enzyme complexed to one of the inhibitors shows occupancy of the tyrosyl binding pocket coupled with inhibitor interactions to key catalytic residues.

Cooperative structural dynamics and a novel fidelity mechanism in histidyl-tRNA synthetases

The crystal structure of the Staphylococcus aureus histidyl-tRNA synthetase apoprotein has been determined at 2.7 A resolution. Several important loops in the active site either become disordered or adopt very different conformations compared to their ligand-bound states. These include the histidine A motif (Arg257-Tyr262) that is essential for substrate recognition, a loop (Gly52-Lys62) that seems to control the communication between the histidine and ATP binding sites, the motif 2 loop (Glu114-Arg120) that binds ATP, and the insertion domain that is likely to bind tRNA. These ligand-induced structural changes are supported by fluorescence experiments, which also suggest highly cooperative dynamics. A dynamic and cooperative active site is most likely necessary for the proper functioning of the histidyl-tRNA synthetase, and suggests a novel mechanism for improving charging fidelity.

The sleep disorder canine narcolepsy is caused by a mutation in the hypocretin (orexin) receptor 2 gene

Narcolepsy is a disabling sleep disorder affecting humans and animals. It is characterized by daytime sleepiness, cataplexy, and striking transitions from wakefulness into rapid eye movement (REM) sleep. In this study, we used positional cloning to identify an autosomal recessive mutation responsible for this sleep disorder in a well-established canine model. We have determined that canine narcolepsy is caused by disruption of the hypocretin (orexin) receptor 2 gene (Hcrtr2). This result identifies hypocretins as major sleep-modulating neurotransmitters and opens novel potential therapeutic approaches for narcoleptic patients.