[A study on major chemical components of Uvaria grandiflora]

OBJECTIVE

To make clear the chemical constituents of Uvaria grandiflora (Annonaceae).

METHODS

Purification was performed using sephadex LH-20 permeation and silica gel chromatography. Structures of the purified components were determined on the basis of 1H, 13C NMR analysis and also by comparison with those of authentic compounds.

RESULTS

Two major triterpenes, suberosol and lupeol, were identified.

CONCLUSION

This paper is the first report on the identification of suberosol and lupeol from the gunus Uvaria.

3-(Diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one (DEPBT): a new coupling reagent with remarkable resistance to racemization

[formula: see text] The new crystalline phosphate reagent 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one (DEPBT) mediates amide bond formation with a remarkable resistance to racemization. Comparative racemization studies were carried out and DEPBT proved to be superior to typical phosphonium and uronium coupling reagents. DEPBT is easily prepared and is exceedingly stable with a shelf life of months at room temperature. The advantageous properties of DEPBT render it a useful and unique addition to the arsenal of coupling reagents.

Mutation analysis of hereditary multiple exostoses in the Chinese

Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2, the two genes responsible for EXT1 and EXT2, respectively, have been cloned. Recently, three other members of the EXT gene family, named the EXT-like genes (EXTL: EXTL1, EXTL2, and EXTL3), have been isolated. EXT1, EXT2, and the three EXTLs are homologous with one another. We have identified the intron-exon boundaries of EXTL1 and EXTL3 and analyzed EXT1, EXT2, EXTL1, and EXTL3, in 36 Chinese families with EXT, to identify underlying disease-related mutations in the Chinese population. Of the 36 families, five and 12 family groups have mutations in EXT1 and EXT2, respectively. No disease-related mutation has been found in either EXTL1 or EXTL2, although one polymorphism has been detected in EXTL1. Of the 15 different mutations (three families share a common mutation in EXT2), 12 are novel. Most of the mutations are either frameshift or nonsense mutations (12/15). These mutations lead directly or indirectly to premature stop codons, and the mutations generate truncated proteins. This finding is consistent with the hypothesis that the development of EXT is mainly attributable to loss of gene function. Missense mutations are rare in our families, but these mutations may reflect some functionally crucial regions of these proteins. EXT1 is the most frequent single cause of EXT in the Caucasian population in Europe and North America. It accounts for about 40% of cases of EXT. Our study of 36 EXT Chinese families has found that EXT1 seems much less common in the Chinese population, although the frequency of the EXT2 mutation is similar in the Caucasian and Chinese populations. Our findings suggest a possibly different genetic spectrum of this disease in different populations.

The effect of amiodarone on the ventricular fibrillation threshold

We evaluated the antifibrillatory effect of two different doses of amiodarone after cardiac arrest with a cardiopulmonary resuscitation (CPR) model in 19 pigs. Ventricular fibrillation was induced by pacing the right ventricle using a primary drive train at a cycle length of 270 msec for 8 beats. The minimum current strength necessary to induce sustained ventricular fibrillation was defined as the ventricular fibrillation threshold (VFT) measured in mA. Three VFT determinations were made at baseline, followed by 9 minutes of continuous CPR with two determinations of VFT, and three after stabilization. The pigs were placed into one of three groups: amiodarone 2 or 5 mg/kg, or placebo. The average poststabilization VFT in each group was compared with the average baseline VFT. Pigs receiving amiodarone 2 mg/kg had significantly higher VFT after stabilization than at baseline (22.88+/-12.76 to 27.10+/-10.18 mA, p=0.048), as did those receiving 5 mg/kg (17.03+/-7.01 to 28.08+/-11.58 mA, p=0.002). The deltaVFT was significantly greater with amiodarone 5 mg/kg than with vehicle (placebo), but not with 2 mg/kg. There were no changes in VFT in any group during CPR versus baseline. When active treatments were combined, the trend was toward better survival in the amiodarone groups (13/13) compared with the placebo group (4/6, p=0.076).

Voltammetric response and determination of DNA with a silver electrode

A current from DNA was obtained using a silver electrode with low overpotentials for the first time. Experimental results revealed that the voltammetric response of DNA was attributed to the redox reactions of purine bases. It was also shown that such a method provided a convenient and practical way to determine DNA. A linear dependence of the peak currents on ssDNA concentrations was observed in the range 0.5-2.5 microg/mL. The relative standard deviation was 3.5% for six successive determinations at 0.5 microg/mL. The detection limit was 50 ng/mL. Influence of the structure and the length of the nucleic acids on their electrochemical behavior was discussed. In view of the merits of the silver electrode, this technique might provide new possibilities for further electrochemical research and determination of nucleic acids.

Tumor necrosis factor-alpha-induced proliferation of human Mo7e leukemic cells occurs via activation of nuclear factor kappaB transcription factor

Tumor necrosis factor-alpha (TNF-alpha) stimulates proliferation of Mo7e, CMK, HU-3, and M-MOK human leukemic cell lines. We report here the signal transduction pathway involved in TNF-alpha-induced Mo7e cell proliferation. Mo7e cells spontaneously die in the absence of growth factors, but treating the cells with interleukin (IL)-3, IL-6, thrombopoietin, granulocyte/macrophage colony-stimulating factor, or TNF-alpha promotes their survival and proliferation. Although most of these factors activate MAP kinase and Jun NH2-terminal kinase/signal transducer and activators of transcription signaling pathways, TNF-alpha fails to activate either pathway. When Mo7e cells were treated with TNF-alpha, nuclear factor kappaB (NF-kappaB) was activated transiently. The activated NF-kappaB consisted of heterodimers of p65 and p50 subunits. The degradation of IkappaBalpha coincided with activation of NF-kappaB in TNF-alpha-treated cells. To investigate the role of activated NF-kappaB in TNF-alpha-induced Mo7e proliferation, a cell-permeable peptide (SN50) carrying the nuclear localization sequence of p50 NF-kappaB was used to block nuclear translocation of activated NF-kappaB. Pretreating Mo7e cells with SN50 blocked TNF-alpha-induced nuclear translocation of NF-kappaB and inhibited TNF-alpha-induced Mo7e cell survival and proliferation. A mutant SN50 peptide did not affect TNF-alpha-induced Mo7e cell growth. SN50 had no effects on IL-3- or granulocyte/macrophage colony-stimulating factor-induced Mo7e cell proliferation. The results indicate that activation of NF-kappaB is involved in TNF-alpha-induced Mo7e cell survival and proliferation.

[Studies on Chinese drugs zhiqiao and zhishi origin investigation and merchandise identification]

OBJECTIVE

To sort out the main original plants of Chinese drugs Zhiqiao and Zhishi.

METHOD

Investigating the medicinal plant resources in the growing area and conducting morphological identification of more than 40 pieces of these two commercial drugs.

RESULT

A taxonomic table, a distribution table and a commercial drug identification table are given. CONVLUSION: The Chinese medicinal plants Zhiqiao and Zhishi originated from Citrus aurantium and its varieties C. aurantium "Xiucheng", C. aurantium "Xiangcheng" and Poncirus trifoliata x C. aurantium, some other plants from Citrus genus and Poncirus trifoliata are taken as the origin of Zhiqiao and Zhishi only in a few areas.

Constitutive activation of the JAK2/STAT5 signal transduction pathway correlates with growth factor independence of megakaryocytic leukemic cell lines

The factor-independent Dami/HEL and Meg-01 and factor-dependent Mo7e leukemic cell lines were used as models to investigate JAK/STAT signal transduction pathways in leukemic cell proliferation. Although Dami/HEL and Meg-01 cell proliferation in vitro was independent of and unresponsive to exogenous cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), and tumor necrosis factor-alpha (TNF-alpha), the growth of Mo7e cells was dependent on hematopoietic growth factors. When these cell lines were cultured in medium without cytokines, a constitutively activated STAT-like DNA-binding factor was detected in nuclear extracts from both Dami/HEL and Meg-01 cells. However, the STAT-like factor was not detectable in untreated Mo7e cells, but was activated transiently in Mo7e cells in response to cytokine treatments. The constitutively activated and cytokine-induced STAT-like DNA-binding factor in these three cell lines was identified as STAT5 by oligonucleotide competition gel mobility assays and by specific anti-STAT antibody gel supershift assays. Constitutive activation of JAK2 also was detected in the factor-independent cell lines, but not in Mo7e cells without cytokine exposure. Meg-01 cells express a p185 BCR/ABL oncogene, which may be responsible for the constitutive activation of STAT5. Dami/HEL cells do not express the BCR/ABL oncogene, but increased constitutive phosphorylation of Raf-1 oncoprotein was detected. In cytokine bioassays using growth factor-dependent Mo7e and TF-1 cells as targets, conditioned media from Dami/HEL and Meg-01 cells did not show stimulatory effects on cell proliferation. Our results indicate that the constitutive activation of JAK2/STAT5 correlates with the factor-independent growth of Dami/HEL and Meg-01 cells. The constitutive activation of JAK2/STAT5 in Dami/HEL cells is triggered by a mechanism other than autocrine cytokines or the BCR/ABL oncoprotein.

[Protein A tangential flow membrane chromatographic column used for immunoadsorption therapy]

Tangential flow membrane chromatographic column is a new model of immunoadsorption therapy from blood. The results showed that the structure of the column and the flowing channel had a little damages for blood cells. The relation of flow-rate and backpressure with water, plasma and blood individually as the fluid flowing through the column has been studied. It was observed that backpressures increased with fluid viscosity, when flow-rate of blood was 120 mL/min and the backpressure reached 0.093 MPa; The adsorption capacity of protein A of the column for IgG from human plasma has been measured. When plasma and blood individually circulated through the column for 1 h, the column with 139 mg protein A immobilized on the matrix (6 mg protein A/g dry matrix) adsorbed 553 mg IgG (23.8 mg IgG/g dry matrix) from human plasma and 499.4 mg IgG (21.5 mg IgG/g dry matrix) from human blood respectively. The circulation time had a great influence on IgG adsorption capacity; but the circulation rate had a little influence on IgG adsorption capacity. The result of extracoporeal blood perfusion for dog showed that the Protein A column has good blood biocompatibility.

A comparison of attitudes towards mental illness and knowledge of mental health services between Australian and Asian students

The aim of this study was to investigate whether Asian immigrants in Australia differed from Anglo-Australians in terms of attitudes towards mental illness, and knowledge of mental health services. A questionnaire was administered to 140 university students, including 63 Anglo-Australian students, 47 Asian students, and 30 students from European backgrounds. The results showed that there was a significant ethnic difference in terms of attitudes towards mental illness, and knowledge of mental health services. Furthermore, Asians who spoke a language other than English at home knew less about services for acute mental illness.

[Histological identification of Chinese drug zhiqiao & zhishi]

After growing area investigating which covered 10 Provinces (or Cities) of China, we gathered 11 types Zhiqiao and 6 types Zhishi which consistently came from 12 species (or varieties). Histological studies on them have been taken. microscopical characters including transverse section and powder were described. These studies will provide scientific basis for the identification of Zhiqiao and Zhishi.

Generation of destabilized green fluorescent protein as a transcription reporter

The green fluorescent protein (GFP) is a widely used reporter in gene expression and protein localization studies. GFP is a stable protein; this property allows its accumulation and easy detection in cells. However, this stability also limits its application in studies that require rapid reporter turnover. We created a destabilized GFP for use in such studies by fusing amino acids 422-461 of the degradation domain of mouse ornithine decarboxylase (MODC) to the C-terminal end of an enhanced variant of GFP (EGFP). The fusion protein, unlike EGFP, was unstable in the presence of cycloheximide and had a fluorescence half-life of 2 h. Western blot analysis indicated that the fluorescence decay of EGFP-MODC-(422-461) was correlated with degradation of the fusion protein. We mutated key amino acids in the PEST sequence of EGFP-MODC-(422-461) and identified several mutants with variable half-lives. The suitability of destabilized EGFP as a transcription reporter was tested by linking it to NFkappaB binding sequences and monitoring tumor necrosis factor alpha-mediated NFkappaB activation. We obtained time course induction and dose response kinetics similar to secreted alkaline phosphatase obtained in transfected cells. This result did not occur when unmodified EGFP was used as the reporter. Because of its autofluorescence, destabilized EGFP can be used to directly correlate gene induction with biochemical change, such as NFkappaB translocation to the nucleus.

[The research fields and advances of biomedical engineering]

The research fields and advances of biomedical engineering have been reviewed in four aspects, biomedical material, biomedical engineering appliance, tele-diagnostic system and biomedical recovery engineering with 14 references.

Chatoyant: a computer-aided- design tool for free-space optoelectronic systems

Chatoyant is a tool for the simulation and the analysis of heterogeneous free-space optoelectronic architectures. It is capable of modeling digital and analog electronic and optical signal propagation with mechanical tolerancing at the system level. We present models for a variety of optoelectronic devices and results that demonstrate the system's ability to predict the effects of various component parameters, such as detector geometry, and system parameters, such as alignment tolerances, on system-performance measures, such as the bit-error rate.

Small-signal-equivalent circuits for a semiconductor laser

Passive electrical circuits whose voltage and current equations are exactly equivalent to the small-signal rate equations of a semiconductor laser are derived to model an electrically modulated laser (verified to be the same as that given in the literature), an optically modulated laser (i.e., a laser used as an optical amplifier), and a multimode laser. These circuits offer a fast and efficient simulation tool with little computational complexity in which the small-signal assumption (i.e., small modulation range) is neither violated nor insufficient for the simulation.

[A study on lens epithelial cell ultrastructure in rhesus monkey cataract]

OBJECTIVE

To investigate the ultrastructure of lens epithelial cells of normal eyes and cataractous eyes in rhesus monkeys.

METHODS

Anterior capsules were taken from 4 normal lenses and 4 cataractous lenses of rhesus monkey eyes, and the samples were observed under transmission electron microscope.

RESULTS

The ultrastructure of the cataractous lens epithelial cells changed obviously. Mitochondria with disappearance of crista were swollen, and vacuolar. Hollow cell with a single large vacuole in the cytoplasm could be seen. The cytoplasm presented dissolution. Cells were swollen and damaged, even cell membrane disruption could be seen. Karyopyknosis, nuclear deformity, disappearance of perinuclear cistern and nuclear pores could be found. The heterochromatin was concentrated and aggregated at the nuclear periphery.

CONCLUSIONS

The ultrastructural changes of the lens epithelial cells in monkey cataractous lens are similar to that in human cataractous lens. Rhesus monkey cataract may be a suitable experimental model to investigate the formation of human cataract.

Effects of amiodarone and its active metabolite desethylamiodarone on the ventricular defibrillation threshold

OBJECTIVES

We evaluated whether the reported difference in the ventricular defibrillation threshold (DFT) between short-term intravenous and oral amiodarone is due to the effect of amiodarone's active metabolite desethylamiodarone (DEA).

BACKGROUND

Amiodarone is frequently used in patients with implantable cardioverter-defibrillator devices (ICD). Long-term oral amiodarone raises the DFT, but intravenous amiodarone has not been shown to have this effect. DEA, an active metabolite of amiodarone, has different electrophysiologic properties than its parent compound and may be responsible for the observed different effects of intravenous and oral amiodarone on DFT.

METHODS

We ascertained the DFT in 24 pigs randomized to receive intravenous amiodarone, DEA or vehicle. Defibrillation was delivered through a transvenous lead system using a biphasic waveform. The DFT was determined using an up-down DFT algorithm and defined as the average minimal energies resulting in successful defibrillation delivered from ascending and descending serial shocks.

RESULTS

Amiodarone caused a dose-response increase in DFT (mean +/- SD) from 22.7 +/- 4.1 (baseline) to 26.1 +/- 2.9 (10 mg/kg body weight), p = 0.11, to 34.9 +/- 8.2 J (after an additional 15 mg/kg), p = 0.035. DEA (10 mg/kg) caused an increase in DFT from 20.5 +/- 6.3 to 33.9 +/- 13.6 J, p < 0.01. Addition of 15 mg/kg of DEA resulted in hemodynamic instability and thus DFT was not obtained. In the control group, DFT decreased from 26.8 +/- 7.7 at baseline to 23.1 +/- 7.4 (dose 1), p = 0.19, to 22.8 +/- 6.2 J (dose 2), p = 0.18.

CONCLUSIONS

DEA increases DFT by a greater amount than its parent drug amiodarone. There is an effect of intravenous amiodarone on DFT that is dose dependent.

The role of type I and type II tumor necrosis factor (TNF) receptors in the ability of TNF-alpha to transduce a proliferative signal in the human megakaryoblastic leukemic cell line Mo7e

We investigated the effects of tumor necrosis factor (TNF) alpha on the human megakaryocytic leukemic cell lines Mo7e, Meg-01, and Dami/HEL. Our data show that both type I and type II TNF receptors (TNF-RI and TNF-RII) are expressed on all of these cells, and TNF-alpha significantly stimulates the proliferation of growth factor-dependent Mo7e cells but not of Meg-01 or Dami/HEL cells, which grow in a factor-independent manner. TNF-alpha serves predominantly as a mitogen for Mo7e cell proliferation and does not induce Mo7e cell differentiation. Coincubation with both TNF-alpha and anti-TNF-alpha neutralizing antibody completely abolishes the TNF-alpha-induced proliferation of Mo7e cells. In bioassays, there is no detectable level of other stimulatory cytokines in conditioned medium from Mo7e cells previously stimulated by TNF-alpha, implying that the stimulatory effect of TNF-alpha on Mo7e cells is derived from the direct action of TNF-alpha rather than via the induction of secondary cytokines by TNF-alpha. Flow cytometric studies demonstrated that TNF-alpha binds to Mo7e cells that have been pretreated with either anti-TNF-RI or anti-TNF-RII neutralizing antibody, but TNF-alpha does not bind to cells pre-exposed to both receptor antibodies. However, the incubation of Mo7e cells with either TNF-RI or TNF-RII neutralizing antibodies or with either soluble TNF-RI or TNF-RII inhibits TNF-alpha-induced cell proliferation, indicating the requirement of interactions with both TNF receptors for the mitogenic activity of TNF-alpha. Furthermore, our data suggest that an alternative signaling pathway may be involved in TNF-alpha-induced Mo7e cell proliferation, because the common mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription (STAT) signaling pathways activated by other cytokines that induce Mo7e cell proliferation are not activated by TNF-alpha.

[A new genus of oral bacteria in human]

A strain, No. 90-1, is isolated from the oral cavity of a patient with periodontophthy. This strain is a Gram-positive, non-endospore-forming, facultative anaerobe with spherical cells, 0.9-1.5 microns in diameter, occuring in pairs and seldom in short chains of four cells, and motile by one flagellum per cell. The optimum growing temperature is 35-37 degrees C; appreciable growth is not found below 10 degrees C, but growth at 53 degrees and tolerance to 60 degrees C for 30 min. This strain is microhalophilous and grows best, well and poorly in the medium containing 2%, 10%-15% and 25% NaCl respectively. Catalase and urease are positive and nitrate is reduced. Acid is produced from many carbohydrates, but no gas. Gelatin can be hydrolyzed, but starch, cellulose and dextrin do not. G + C content in DNA is 41.34 mol%(Tm). The strain(90-1) is considered to be a new species belonging to a new genus because its some characteristics are different from those of the known coccus genuera and designated as Stomatostreptococcus microhalophilus Ping, Zhou, Sun et Fan gen. nov. sp. nov. according to its source and microhalophilic trait.

Efficacy of intravenous granisetron in suppressing the bradycardia and hypotension associated with a rabbit model of the Bezold-Jarisch reflex

This study investigated whether granisetron, a 5-HT3 receptor antagonist, can alter the Bezold-Jarisch reflex (i.e., hypotension and inappropriate heart rate slowing). A hemorrhagic rabbit model that has been shown to induce the Bezold-Jarisch reflex was used. In 11 rabbits (3.8 kg), catheters were placed in the carotid arteries one day before experimental hemorrhage. On the day of the study, the rabbits were given intravenous granisetron (50 micrograms/kg) or an equal volume of saline. Five minutes after administration of granisetron or saline, hemorrhage was induced by continuous blood withdrawal at 5 mL/min and blood pressure (BP) and heart rates were obtained at frequent intervals until systolic BP declined to 80 mmHg. Six rabbits received saline and five granisetron. An average of 77.6 mL +/- 16.4 mL of blood was removed in the group receiving granisetron (compared with 56.5 mL +/- 13.1 mL for the saline group) before achieving the target systolic BP of 80 mmHg. The group receiving granisetron demonstrated the same ability to increase their heart rate from baseline as the saline group. However, the granisetron group had a final heart rate that was closer to their maximal heart rate than the saline group. In this animal model, granisetron was significantly more effective at preventing inappropriate heart rate slowing and allowed significantly more blood to be removed before reaching the target blood pressure. This implies that granisetron may be effective in preventing vasovagal syncope, although further study should be carried out to verify these potentially interesting findings.

The determinative role of intraoperative echo in tricuspid valvuloplasty

A transesophageal echocardiography (TEE) was used in monitoring the operation of tricuspid valvuloplasty. Nine patients with rheumatic heart disease were studied. The results showed that intraoperative TEE was important on the improving method of tricuspid annuloplasty, it help to determine surgical procedure, control annulus-reducing procedure and assess the result immediately after operation. The results suggested that intraoperative TEE can be widely used in valvuloplasty in future.

Stability of omeprazole in an extemporaneously prepared oral liquid

The stability of omeprazole 2 mg/mL. in an extemporaneously prepared oral liquid was studied. The contents of five 20-mg omeprazole capsules were mixed with 50 mL of 8.4% sodium bicarbonate solution in a Luer-Lok syringe. Three vials of this liquid were prepared for storage at 24, 5, and -20 degrees C. A 3-mL. sample of each was taken initially and on days 1, 2, 3, 4, 6, 8, 10, 12, 14, 18, 22, 26, and 30 and assayed by high-performance liquid chromatography. The liquids stored at 5 degrees C and at -20 degrees C did not change color during the study period, but the color of the liquid stored at 24 degrees C changed from white to brown. There were no significant changes in the omeprazole concentrations of the liquids stored at 5 and -20 degrees C during the study period, but the omeprazole concentration of the liquid stored at 24 degrees C was < 90% of the initial concentration on day 18. Omeprazole 2 mg/mL in an oral liquid compounded extemporaneously from capsules and sodium bicarbonate injection was stable for up to 14 days at 24 degrees C and for up to 30 days at 5 and -20 degrees C.

Stability of granisetron hydrochloride in an extemporaneously prepared oral liquid

The stability of granisetron 0.2 mg/mL (as the hydrochloride salt) in an extemporaneously prepared oral liquid was studied. Twelve 1-mg granisetron tablets were pulverized and suspended in 30 mL of distilled water. This mixture was then diluted with cherry syrup to produce a 60-mL oral liquid with a granisetron concentration of 0.2 mg/mL. Half of the preparation was stored at 5 degrees C, and half was stored at 24 degrees C. Samples were taken on days 0, 1, 2, 3, 4, 6, 8, 10, 12, and 14 and assayed by high-performance liquid chromatography. There was no change in the liquid's color, consistency, or pH, and the concentrations of granisetron ranged from 97% to 104% of initial concentration during the 14 days at 5 and 24 degrees C. Granisetron 0.2 mg/mL (as the hydrochloride salt) in an extemporaneously prepared oral liquid was stable for up to 14 days.

[Immuno-enhancing effect of gebie oral liquid on mice]

Gebie Oral Liquid can increase the weight of thymus and spleen of the mouse, damaged by prednisone and cytoxan, enhance the phagocytosis of monocytes and DHT, and promote the blastogenesis of splenic lymphocytes as well as the activity of NK cells.

D-alanine:D-alanine ligase: phosphonate and phosphinate intermediates with wild type and the Y216F mutant

The crystallographic structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli complexed with a D-Ala-D-alpha-hydroxybutyrate phosphonate and the structure of the Y216F mutant ligase complexed with a D-Ala-D-Ala phosphinate have been determined to 2.2 and 1.9 A resolution, respectively, and refined to R factors of 0.156 and 0.158. In each complex the inhibitor has reacted with ATP to produce ADP and a tight-binding phosphorylated transition state intermediate. Comparison of these two structures with the known crystal structure of the phosphinate intermediate of the wild-type ligase shows no major conformational changes, but B factors indicate differences in mobility of loops covering the binding site. The weaker inhibition of the Y216F mutant by both inhibitors is thought to be due in part to the loss of an interloop hydrogen bond. A similar mechanism may account for poor inhibition of VanA, the homologous D-Ala:D-lactate ligase produced by vancomycin-resistant enterococci.

[The effect of alkalinity of methylation reagent on isomerization and degradation of polyunsaturated fatty acids with pyrolysis gas chromatography]

Simultaneous pyrolysis and methylation gas chromatography (SPM-GC) is a fast analytical method which was developed in recent years. However, the strong alkalinity of tetramethylammonium hydroxide (TMAH) may result in the isomerization and degradation of polyunsaturated fatty acids in oils and fats during analysis. This paper describes the application of SPM-GC to polyunsaturated fatty acids in soybean oil and the isomerization and degradation may be prevented by choosing the optimum proportion of TMAH to methanol which is 1:50 (pH 8.8). With this chosen optimum proportion there were no detectable isomerized and degraded peaks in the chromatograms. Pyrograms were obtained by interfacing a Curie-point pyrolyser to a Shimadzu GC-14A gas chromatograph equipped with a flame ionisation detector. A capillary column (FFAP) was used. All of the pyrolysis products were identified by mass spectrometry which was carried out with a Varian 3400 gas chromatograph interfaced to a Finnigan SSQ 710 mass spectrometer using electron impact ionisation (70 eV). This method is simpler and more convenient than both the methods "neutralization of acid" and "simultaneous injection of the sample and a short chain fatty acid methylester" reported in the previous papers.

[Preliminary study on separation of three vitamins by capillary zone electrophoresis and micellar electrokinetic chromatography with amperometric electrochemical detection]

In this paper, separation of water soluble vitamins C (VC), B1 (VB1) and B6 (VB6) has been studied preliminarily by capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) with a home-made amperometric electrochemical detector at the working electrode [carbon fiber (5 microm o.d.)] potential of 510-540 mV (vs. SCE). It has been shown that each of the three vitamins has more than one peak in NH3-NH4Cl (pH 9.0) which were mainly caused by the decomposition products in weak base medium and by heat except those from impurities. The electrochemical detector has better performance for the three vitamins from CZE and MECC. They can be separated either by CZE or by MECC. The separation by CZE is better than that by MECC with sodium dodecyl sulfate (SDS). SDS and buffer acidity can influence the retention time, peak sequence and height. The separation efficiency of CZE in 0.01 mol/L NH3-NH4Cl was 468 800 theoretical plates for VC.

Nuclear matrix of human nasopharyngeal carcinoma cells in culture

Nuclear matrix is a scaffold-like structure of the nucleus after sequential treatments with detergents, DNase, and high salt buffers. Its involvement in various cellular activities has been emphasised in various studies. In this study, nuclear matrix of two human nasopharyngeal carcinoma cell Lines were compared and analysed in terms of their morphological appearance and electrophoretic patterns of proteins. The stability of nuclear matrices against enzymatic digestion was found to be similar in these two cell lines. However, cell line specific nuclear matrix proteins were detected in each cell line. The significance of these proteins in cellular function and oncogenesis will be investigated in due course.

Effect of chronic oral moricizine and intravenous epinephrine on ventricular fibrillation and defibrillation thresholds

The purpose of this study was to determine the effects of chronic oral moricizine therapy and physiological doses of epinephrine on ventricular fibrillation and defibrillation thresholds using an implantable transvenous/subcutaneous defibrillation system in a pig model. Thirteen pigs completed the three phases of the study. After a baseline study on day 1, the animals were randomized to receive moricizine 10-15 mg/kg tid or placebo for seven doses, at which time the protocol was repeated on day 4. The same protocol was again repeated on the same day after infusion of physiological doses of epinephrine. Multiple ventricular fibrillation and defibrillation thresholds were measured during each study. Moricizine did not alter ventricular fibrillation nor defibrillation thresholds, whereas epinephrine increased the ventricular defibrillation threshold from 20.8 J to 23.7 J (P < 0.05). In addition, we observed an increase in both ventricular fibrillation (19.7 J vs 12.6 J; P < 0.05) and defibrillation (20.8 J vs 17.8 J; P 0.05) thresholds over the 4 days of the study. These findings suggest that moricizine may be a safe antiarrhythmic agent to use in patients with implantable cardioverter defibrillators, and that elevated endogenous epinephrine may render defibrillation more difficult.

p53 polymorphisms and haplotypes in nasopharyngeal cancer

Three p53 DNA polymorphisms (BstUI and MspI RFLPs in exon 4 and intron 6, respectively, and a 16-bp duplication in intron 3) and their haplotype combinations were studied in 73 patients (61 males and 12 females) with nasopharyngeal cancer and 105 healthy controls from the Guizhou province in southern China. Increased frequencies of the 16-bp A2 allele (p = 0.005), MspI A1 allele (p = 0.021) and the BstUI A1 (Pro) allele (p = 0.072) were found among the patients, with more pronounced differences in male patients (p = 0.003, 0.014 and 0.052, respectively). Haplotype frequencies and linkage disequilibria differed from those in Caucasians. The differences between controls and patients, especially male patients, increased when the analysis was based on haplotypes. The lowest risk for nasopharyngeal cancer was associated with the haplotype 16-bp A1, BstUI A2, MspI A2 (1-2-2). A somewhat higher risk was observed in the 1-1-2 haplotype (replacing the Arg with a Pro allele). The highest risk was, however, found in the rare combinations including the 16-bp A2 and MspI A1 alleles with an odds ratio of 4.9 [95% confidence interval (CI) = 1.8-13.2] in all patients and 5.4 (95% CI = 2.0-14.8) in male patients. The haplotype associations found in this study differ from those found in previous cancer association studies in Caucasians. This together with the fact that the intronic markers conferred the highest risk figures suggest that the mechanism behind the observed associations is linkage disequilibrium and not direct functional involvement of the codon 72 alleles.

Association between orosomucoid types and cancer

Orosomucoid (ORM) is a polymorphic acute-phase reactant with immunosuppressive properties. Previous investigations have suggested that ORM and other acute-phase reactants may act as blocking factors protecting tumor cells against immunological attack, thereby contributing to the 'immune escape' of the tumor. ORM types were studied by isoelectric focusing and immunoprinting in patients with carcinoma of the breast, lung, ovary and endometrium and in population controls. In accordance with a previous study, the frequencies of the ORM1*2 allele and the ORM1 2 phenotype were found to be significantly increased in patients with different types of carcinomas. The results suggest that the ORM1 2 variant may influence the progression of cancer by being more immunosuppressive than the ORM1 1 variant. The relative risk for carcinoma in patients with the ORM1 2 type was 1.56 (95% confidence interval:1.16-2.09).

Digital free-space optical interconnections: a comparison of transmitter technologies

We investigate the performance of free-space optical interconnection systems at the technology level. Specifically, three optical transmitter technologies, lead-lanthanum-zirconate-titanate and multiple-quantum-well modulators and vertical-cavity surface-emitting lasers, are evaluated. System performance is measured in terms of the achievable areal data throughput and the energy required per transmitted bit. It is shown that lead-lanthanum-zirconate-titanate modulator and vertical-cavity surface-emitting laser technologies are well suited for applications in which a large fan-out per transmitter is required but the total number of transmitters is relatively small. Multiple-quantum-well modulators, however, are good candidates for applications in which many transmitters with a limited fan-out are needed.

Orosomucoid types in allergic contact dermatitis

Orosomucoid (ORM) is an immunosuppressive acute-phase reactant controlled by two different loci: ORM1 and ORM2. In previous studies, the ORM1 1 type has been found to be associated with psoriasis and sarcoidosis, presumably by influencing the progression and clinical course of these disorders. In this report, a significant association between the ORM1 1 type and allergic contact dermatitis in male patients (relative risk = 1.9, 95% confidence interval = 1.0-3.6) is presented.

A common fold for peptide synthetases cleaving ATP to ADP: glutathione synthetase and D-alanine:d-alanine ligase of Escherichia coli

Examination of x-ray crystallographic structures shows the tertiary structure of D-alanine:D-alanine ligase (EC 6.3.2.4). a bacterial cell wall synthesizing enzyme, is similar to that of glutathione synthetase (EC 6.32.3) despite low sequence homology. Both Escherichia coli enzymes, which convert ATP to ADP during ligation to produce peptide products, are made of three domains, each folded around a 4-to 6-stranded beta-sheet core. Sandwiched between the beta-sheets of the C-terminal and central domains of each enzyme is a nonclassical ATP-binding site that contains a common set of spatially equivalent amino acids. In each enzyme, two loops are proposed to exhibit a required flexibility that allows entry of ATP and substrates, provides protection of the acylphosphate intermediate and tetrahedral adduct from hydrolysis during catalysis, and then permits release of products.

Comparison of personality traits of only and sibling school children in Beijing

The number of only children in China has increased rapidly since the late 1970s, when the Chinese government advocated the "one-child-per-family" policy. This increase has caused much public concern about the healthy growth of the young generation. In this study the behavioral traits of Chinese, urban, only children were investigated. The participants were 444 children with siblings and 473 only children from Grades 1, 3, and 5 in Beijing primary schools. An inventory consisting of 27 items covering three behavioral traits was developed. The children were rated on the inventory by the principal teacher of the class. Factor analysis revealed three main factors: achievement motivation, interpersonal skills, and attitude toward manual labor. The only children exceeded the sibling children on achievement motivation. No differences were found between only children and sibling children on interpersonal skills and attitude toward manual labor. Gender differences were evident; girls consistently received higher ratings on achievement motivation and interpersonal skills. The possible underlying reasons for these differences are discussed.

Vancomycin resistance: structure of D-alanine:D-alanine ligase at 2.3 A resolution

The molecular structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli, co-crystallized with an S,R-methylphosphinate and adenosine triphosphate, was determined by x-ray diffraction to a resolution of 2.3 angstroms. A catalytic mechanism for the ligation of two D-alanine substrates is proposed in which a helix dipole and a hydrogen-bonded triad of tyrosine, serine, and glutamic acid assist binding and deprotonation steps. From sequence comparison, it is proposed that a different triad exists in a recently discovered D-alanine:D-lactate ligase (VanA) present in vancomycin-resistant enterococci. A molecular mechanism for the altered specificity of VanA is suggested.

Clinical assessment of biplanar transesophageal echocardiography--a report of 125 cases

One hundred and twenty-five patients with cardiovascular disease were examined by biplanar transesophageal echocardiography (BTEE), including 67 with rheumatic heart disease (7 monitored during operation), 22 with aortic diseases, 20 with congenital heart diseases, and 16 with other kinds of heart disease. The results showed that BTEE was not influenced by corpulent and pulmonary emphysema and was better than transthoracic echocardiography at imaging the interatrial septum, left atrium and left atrial appendage, thoracic aorta, and mitral artificial valve and at intraoperative monitoring. BTEE was also better than single-plane transesophageal echocardiography, because BTEE could be used to observe the heart and thoracic aorta in transverse and longitudinal planes, thus enlarging the transmission "window" as well as allowing the entire lesion to be imaged. This study suggests that BTEE will have good prospects in clinical application.