Ellipsometry and Infrared Reflection Absorption Spectroscopy of Adsorbed Layers of Soluble Surfactants at the Air-Water Interface

Optical techniques play an increasingly important role in the characterization of microstructure and surface densities of thin films at various interfaces. In this study, ellipsometry and infrared reflection absorption spectroscopy (IRRAS) were used for determining the surface densities of adsorbed layers of cationic surfactants in situ at the air-water interface. The surfactants were N(alpha)-lauroyl-arginine methyl ester (LAM) and N(alpha), N(omega)-bis(N(alpha)-lauroyl-arginine)-alpha,omega-alkylidenediamide (C(6)(LA)(2)). In ellipsometry, the ellipsometric phase angle Delta was obtained at various surfactant concentrations and was referenced to that of the solvent. Three algorithms were used for analyzing the data. The surface densities are 3.3+/-0.3x10(-6) mol/m(2) at 1 mM for LAM and 1.5+/-0.3x10(-6) mol/m(2) at 0.1 mM for C(6)(LA)(2) by using an algorithm for which the monolayer thickness was estimated from molecular modeling. The corresponding surface densities from literature surface tension data and the Gibbs adsorption isotherm procedure are 2.2+/-0.4x10(-6) mol/m(2) and 1.2+/-0.2x10(-6) mol/m(2), respectively. In addition, IRRAS spectra were obtained from monolayers of LAM and C(6)(LA)(2) at the air-water interface. The frequencies of the methylene stretching vibration bands indicate that the monolayers are liquid-like. The surface densities were determined from the reflectance-absorbance data by using the model of either an isotropic film or an anisotropic film on the aqueous subphase. The IRRAS-based surface densities from either model, by using DPPC monolayers for calibration, are 2.4+/-0.7x10(-6) mol/m(2) at 1 mM for LAM and 1.5+/-0.6x10(-6) mol/m(2) at 0.1 mM for C(6)(LA)(2), which are in fair agreement with the ellipsometry- and the surface-tension-based surface densities. Copyright 2001 Academic Press.

Protein-tyrosine phosphatase D1, a potential regulator and effector for Tec family kinases

Etk, also named Bmx, is a member of the Tec tyrosine kinase family, which is characterized by a multimodular structure including a pleckstrin homology (PH) domain, an SH3 domain, an SH2 domain, and a catalytic domain. The signaling mechanisms regulating Etk kinase activity remain largely unknown. To identify factor(s) regulating Etk activity, we used the PH domain and a linker region of Etk as a bait for a yeast two-hybrid screen. Three independent clones encoding protein-tyrosine phosphatase D1 (PTPD1) fragments were isolated. The binding of PTPD1 to Etk is specific since PTPD1 cannot associate with either the Akt PH domain or lamin. In vitro and in vivo binding studies demonstrated that PTPD1 can interact with Etk and that residues 726-848 of PTPD1 are essential for this interaction. Deletion analysis of Etk indicated that the PH domain is essential for PTPD1 interaction. Furthermore, the Etk-PTPD1 interaction stimulated the kinase activity of Etk, resulting in an increased phosphotyrosine content in both factors. The Etk-PTPD1 interaction also increased Stat3 activation. The effect of PTPD1 on Etk activation is specific since PTPD1 cannot potentiate Jak2 activity upon Stat3 activation. In addition, Tec (but not Btk) kinase can also be activated by PTPD1. Taken together, these findings indicate that PTPD1 can selectively associate with and stimulate Tec family kinases and modulate Stat3 activation.

[Study of the correlation between in vitro and in vivo evaluation methods on biomaterials--DNA test and muscular implant test]

With the wide-spread use of biomaterials, the safety evaluation on biomaterials has become a very important step. This study on the correlation between DNA test and muscular implant test was done for finding out good in vitro evaluation method. The tissue toxicities of seven biomaterials were examined. Good correlation between DNA test and muscular implant test was demonstrated by Spearman sequential correlation analysis.

Salivary cellular signaling and gene regulation

Protein tyrosine kinase and protein serine kinase activation has been implicated in the regulation of salivary cell proliferation and differentiation. Aberrant expression and alterations of certain tyrosine or serine kinases, such as Raf or erbB2, are known to trigger salivary tumor development (Li et al., 1997; Cho et al., 1999). It has been estimated that there are about 1000 to 2000 protein kinases in the mammalian genome, with 100 to 200 of them (i.e., 10%) being tyrosine kinase (Hanks and Hunter, 1995). At present, there are approximately 85 different tyrosine kinases identified in the GenBank database. Based on the relatively slow rate of discovery in the past few years, 100 is a better approximation of the total number of tyrosine kinases encoded by each mammalian genome. It is reasonable to assume that there are about 30 to 50 tyrosine kinases expressed in a given cell at a given differentiation/proliferation stage. This number is large enough to provide a characteristic tissue-specific tyrosine kinase expression profile, but small enough to be identified in a simple screening. The hope for tyrosine kinases as differentiation or proliferation markers rests with the possibility for the identification and characterization of a differentiation/proliferation stage-specific expression pattern in salivary cells. Several ligands that transmit signal through receptor tyrosine kinases and/or Ras/Raf/ERK kinases have been extensively studied in salivary cells. This review focuses mainly on the signaling pathways activated by Raf and Etk.

[Synergistic effect of monocyte chemotactic protein-1 and aristolochic acid I on transdifferentiation of human tubular epithelial cells in vitro]

OBJECTIVE

To test the possible role of monocyte chemotactic protein-1 (MCP-1) and its synergistic effect with aristolochic acid I (AAI) on tubular epithelial-myofibroblast transdifferentiation (TEMT) of human renal tubular epithelial cells (HKC) in vitro.

METHODS

The cultured HKC cells were divided into four groups: (1) negative control (serum-free); (2) MCP-1 group; (3) AAI group; (4) AAI + MCP-1 group. The expression of alpha-smooth muscle actin (alpha-SMA), vimentin and cytocreatin was assessed by indirect enzyme immunohistochemistry and the percentages of alpha-SMA((+)) HKC cells were assessed by flow cytometry.

RESULTS

The expression of cytocreatin of HKC cells decreased, while the expression of alpha-SMA, vimentin increased when treated with MCP-1 or with AAI and MCP-I concomitantly. Alpha-SMA((+)) HKC cells cultured in serum-free medium was 3.1% by flow cytometry. The percentages of alpha-SMA((+)) HKC cells were 8.6%, 9.6%, 13.4% (P < 0.05 vs control) when treated with 20, 40, 80 microg/L of AAI. The percentages of alpha-SMA((+)) HKC cells were 0.5% and 1.4% (P > 0.05 vs control) when treated with 5, 10 microg/L. The percentages of alpha-SMA((+)) HKC cells were 20%, 26.2%, 20.3%, 23.2% (P < 0.05 vs control) when treated with 0.001, 0.01, 0.05, 0.1 microg/L of MCP-1. When the HKC cells were treated with MCP-1 (0.1 microg/L) and AAI (5, 10, 20, 40 microg/L), the percentage of alpha-SMA((+)) cells increased markedly to 23.2%, 98.7%, 81.5%, 65.1% (P < 0. 01 vs group 1, 2, 3, respectively).

CONCLUSIONS

These findings suggest that: (1) MCP-1 may induce the transdifferentiation of HKC cells into myofibroblasts in vitro; (2) AAI at some doses may partially induce HKC cells transdifferentiation. (3) MCP-1 and AAI may have a synergistic effect on transdifferentiation of HKC cells in vitro.

High-pathogenicity island of Yersinia spp. in Escherichia coli strains isolated from diarrhea patients in China

The high-pathogenicity island (HPI) of Yersinia has been observed in 93% of 60 enteroadhesive Escherichia coli strains and 80% of E. coli strains isolated from blood samples. In the present study we investigated 671 fecal samples from patients with diarrhea in Shandong Province, China, and isolated HPI-harboring E. coli from 6. 26% of the samples. The isolation rates for patients with diarrhea in three age groups, 10 to 20, 30 to 40, and 50 to 60 years, were 6. 70, 12.35, and 10.81%, respectively. Therefore, HPI-harboring E. coli is the third most frequently isolated enteric pathogen from patients with diarrhea. Vomiting and abdominal pain were recorded for 33.33 and 66.67% of the patients, respectively. Stools with blood were observed for 9.52% of the patients. Twenty-four of 42 (57%) patients experienced a temperature over 37.4 degrees C. These observations indicate that HPI-harboring E. coli is one of the major causes of diarrheal disease in China and that the clinical symptoms caused by HPI-harboring E. coli differ from those caused by enteroadhesive E. coli.

Effect of Protonation on the Solution and Phase Behavior of Aqueous Sodium Myristate

Aqueous sodium myristate solutions have been shown to have unusually low dynamic tensions (1-10 mN/m) under pulsating area conditions. These solutions have no sharp solubility limit, evidently because they are protonated (or "hydrolyzed") to form the much less soluble myristic acid and acid soaps. With no added electrolytes, the protonation fraction is 1% or less. The apparent protonation equilibrium "constant" increases with increasing concentration, indicating strong solution nonidealities, in addition to micellization. This protonation seems to affect the solution and phase behavior of aqueous sodium myristate strongly, as evidenced by the effect of added NaOH. Ion-selective electrodes (for Na(+) and H(+)) and conductimetry indicate that at 25 degrees C dissolved surfactant concentrations keep increasing well after dispersed particles are observed (2 mM). A cmc of about 4.5 mM, micelles of aggregation number n=70 and counterion binding parameter beta=0.7 are inferred from these techniques. The cmc of sodium myristate increases slightly with temperature from 25 to 45 degrees C. FTIR analysis of the filtered particles indicates that the dispersed particles are mainly acid soaps for concentrations less than 6 mM. With 10 mM NaOH, the particles observed above 2 mM consist mostly of sodium myristate. From both conductivity and IR data, the solubility of sodium myristate in water at 25 degrees C is estimated to be about 6 mM, and as expected, it increases with increasing temperature and decreases with increasing sodium ion concentration. Copyright 2000 Academic Press.

In vitro bioactive behavior of hydroxylapatite-coated porous Al(2)O(3)

To produce bioactive materials for bone substitutes, two major deposition methods, suspension method and thermal deposition method, were employed to develop bioactive, mechanically strong, and porous ceramics. Hydroxylapatite (HA) has been uniformly coated onto inner pore surfaces of reticulated alumina substrates. It has been found that the in vitro bioactivity of HA coatings was affected by both structural crystallinity and specific surface area. Well-crystallized HA heat-treated at high temperatures has resulted in reduced bioactivity. The bio-reaction rate was found to increase with the surface area of HA. We have found that the stability of the well-crystallized HA is associated with the high driving force required for the formation of hydroxy-carbonate apatite (HCA) phase.

Theoretical and numerical predictions of two-dimensional Aaberg slot exhaust hoods

Theoretical and computational fluid dynamical techniques are employed to predict the two-dimensional turbulent air flows which are created by an Aaberg slot exhaust hood, which is reinforced by a two-dimensional wall jet flow. The aim of the two-dimensional model is to numerically reveal the characteristics of the air flow in the central plane of the Aaberg workbench. A further development of the potential model is through the inclusion of the finite slot. We have found that the numerical results for the streamlines and the lines of constant speed produced by the potential flow model are in good agreement with those obtained when using the full turbulent flow model and the air velocity distribution predicted by both the potential and turbulent models agree very well with all the available experimental data. The comparison between the potential and the turbulent models reveals that the potential model has the advantage over the turbulent model in that there is much less uncertainty in the results obtained due to the more accurate specification of the boundary conditions on the open boundaries at large distances from the hood.

[Tracheal transplantation]

OBJECTIVE

To treat long tracheal cancer by tracheal transplantation.

METHODS

In March 17, 1999, a patient received a total laryngeal resection and a resection of 8 cm upper and middle trachea, which was replaced by a 6 cm long trachea of another donor. The donor trachea was dipped first in preservation liquid A for sterilization for 24 hours, then in preservation liquid B for over 48 hours for destructing MHC. Pedunculated greater omentum and pedunculated greater pectoral musculus supplied the blood for the donor trachea. One side of the donor was anastomosed with the lower trachea, and the other with the neck skin.

RESULTS

The patient survived 300 days after operation. The auto tracheal membrane covered the donor surface; auto- and xeno trachea was well anastomose. The new trachea grew very well.

CONCLUSION

Trachea transplantation is possible the best method to treat long tracheal disease if the transplantable trachea is less 5 cm.

[The effect of brain-derived neurotrophic factor on the rat electroretinography after pressure-induced ischemic injury]

Brain-derived neurotrophic factor (BDNF) or normal goat serum (NGS) was injected intravitreously in each 11 wistar albino rats two days before the induction of ischemia. Retinal ischemia was induced in 22 rats by increasing intraocular pressure to the threshold level which extinguished the electroretinography (ERG) b-wave individually, and maintaining for 90 minutes. The ERG b-wave of the BDNF-treated rats recovered to 80.5 +/- 24.4% of their normal amplitude three days after ischemia, while that of the NGS-treated rats recovered only to 11.1 +/- 5.3%. Statistic analysis showed that the recovery level of ERG b-wave after ischemia in the BDNF and NGS treated rats was significantly different (P < 0.01). The results suggest that BDNF could promote the recovery of the retinal electrophysiologic function from ischemia induced by high intraocular pressure.

Synthesis of aminocyclopentitols from chromium carbene complex derived aminocyclobutanones

Functionalized cyclopentenones were synthesized by the diazomethane ring expansion of cyclobutanones, produced by the photochemical reaction of vinyl oxazolidinones with chromium carbene complexes.

Purification, cloning, and characterization of the CEL I nuclease

CEL I, isolated from celery, is the first eukaryotic nuclease known that cleaves DNA with high specificity at sites of base-substitution mismatch and DNA distortion. The enzyme requires Mg(2+) and Zn(2+) for activity, with a pH optimum at neutral pH. We have purified CEL I 33 000-fold to apparent homogeneity. A key improvement is the use of alpha-methyl-mannoside in the purification buffers to overcome the aggregation of glycoproteins with endogenous lectins. The SDS gel electrophoresis band for the homogeneous CEL I, with and without the removal of its carbohydrate moieties, was extracted, renatured, and shown to have mismatch cutting specificity. After determination of the amino acid sequence of 28% of the CEL I polypeptide, we cloned the CEL I cDNA. Potential orthologs are nucleases putatively encoded by the genes BFN1 of Arabidopsis, ZEN1 of Zinnia, and DSA6 of daylily. Homologies of CEL I with S1 and P1 nucleases are much lower. We propose that CEL I exemplifies a new family of neutral pH optimum, magnesium-stimulated, mismatch duplex-recognizing nucleases, within the S1 superfamily.

[Detection of Escherichia coli strains harboring pathogenicity island of Yersinia enterolitica in diarrheal patients and animals in China]

OBJECTIVE

To investigate the prevalence of Escherichia coil strains harboring high pathogenicity island of Yersinia enterocolitica in diarrhea patients, animals, food samples and resulted clinical symptoms.

METHODS

Colony hybridization, DNA dot hybridization and polymerase chain reaction (PCR) were used.

RESULTS

HPI - harboring E. coli were found in the strains isolated in various provinces of China. The isolation rates were 27.05% (436/1,612) in the strains isolated from diarrhea patients, 10.23% (9/88) in the strains isolated from food samples and 5.71% (16/280) in the strains isolated from feces of cattle and pigs. Typical clinical symptoms of diarrhea caused by HPI - harboring E, coli were inappetency, abdominal pain, shiver and vapidity. Patient's temperature was usually normal or low. Over six episodes of diarrhea was frequently observed, of which most were unformed stools with mucous.

CONCLUSION

E. coli strains harboring high - pathogenicity - island of Yersinia species were frequently isolated from diarrhea patients, animals and food samples as well, which might be one of the major causes of diarrhea in China.

Large-scale identification of differentially expressed genes during neurogenesis

We report here a modified mRNA differential display method and its application for the analysis of differential gene expression in NGF-treated PC12 cells and in embryonic rat spinal cord. The optimized protocol is based on low fidelity priming of multiple cDNAs followed by high fidelity amplification. In PC12 cells induction by nerve growth factor (NGF) altered the expression of 4% of the 466 transcripts evaluated. During neurogenesis of the spinal cord we found that 30% of the 288 examined products changed. The differential expression of the characterized genes was confirmed by independent quantitative PCR. We conclude this method is suitable for the identification of increases and decreases of mRNA levels and allows the discovery of differentially expressed unknown transcripts.

The application of shannon entropy in the identification of putative drug targets

A major challenge in the field of functional genomics is the development of computational techniques for organizing and interpreting large amounts of gene expression data. These methods will be critical for the discovery of new therapeutic drug targets. Here, we present a simple method for determining the most likely drug target candidates from temporal gene expression patterns assayed with reverse-transcription polymerase chain reaction (RT-PCR) and DNA microarrays.

Kinase activation of the non-receptor tyrosine kinase Etk/BMX alone is sufficient to transactivate STAT-mediated gene expression in salivary and lung epithelial cells

Etk/BMX is a non-receptor protein tyrosine kinase that requires a functional phosphatidylinositol 3-kinase via the pleckstrin homology domain to be activated by cytokine. In the present study, a conditionally active form of Etk was constructed by fusing the hormone-binding domain of estrogen receptor (ER) to an amino terminus truncated form of Etk, PHDelta1-68Etk, to generate DeltaEtk:ER. In stably transfected Pa-4DeltaEtk:ER cells, the activity of DeltaEtk:ER was stimulated within minutes by the treatment of DeltaEtk:ER stimulant, estradiol, and sustained for greater than 24 h. A robust induction in the phosphorylation of signal transducers and activators of transcription (STAT) proteins, including STAT1, STAT3, and STAT5, was accompanied with DeltaEtk:ER activation. Moreover, the conditionally activated Etk stimulated STAT1- and STAT5-dependent reporter activities by approximately 160- and approximately 15-fold, respectively, however, elicited only a modest STAT3-mediated reporter activation. Qualitatively comparable results were obtained in lung A549 cells, indicating that DeltaEtk:ER inducible system could function in an analogous fashion in different epithelial cells. Furthermore, we demonstrated that Etk activation alone augmented cyclin D1 promoter/enhancer activity via its STAT5 response element in both Pa-4DeltaEtk:ER and A549 cells. Altogether, these findings support the notion that the activation of Etk kinase is sufficient to transactivate STAT-mediated gene expression. Hence, our inducible DeltaEtk:ER system represents a novel approach to investigate the biochemical events following Etk activation and to evaluate the contribution by kinase activation of Etk alone or in conjunction with other signaling pathway(s) to the ultimate biological responses.

High-level expression of I kappa B-beta in the surface epithelium of the colon: in vitro evidence for an immunomodulatory role

The intestinal epithelium is spatially segregated into two compartments, one containing undifferentiated cells in a proliferative state and one with non-proliferative differentiated cells. Although this epithelium can produce many immunemodulating substances, emerging evidence suggests that the differentiated cell compartment is less immune responsive. Indeed, it is the differentiated cellular compartment that represents the interface between the highly antigenic luminal environment and the mucosal immune system. The NF-kappaB/rel family of transcriptional activators play a critical role in regulating the inflammatory response by activating a wide variety of immune-modulating genes. These transcription factors are maintained in an inactive state in the cytoplasmic compartment by interaction with inhibitory proteins of the IkappaB family. In this study we show by immunohistochemistry that IkappaB-beta is expressed at high levels specifically in the differentiated surface epithelium of the colonic mucosa. Using a naturally occurring compound found in the colon of vertebrates, butyrate, we provide evidence in an intestinal cell line that alteration of IkappaB-beta expression can modulate the transcriptional activation of the interleukin-8 (IL-8) gene by preventing the nuclear translocation of NF-kappaB proteins. Therefore, the expression of IkappaB-beta in the differentiated surface epithelium of the colon may help these cells act as an immunological barrier to prevent activation of the mucosal immune system.

Fluvoxamine is a more potent inhibitor of lidocaine metabolism than ketoconazole and erythromycin in vitro

CYP3A4 is generally believed to be the major CYP enzyme involved in the biotransformation of lidocaine in man; however, recent in vivo studies suggest that this may not be the case. We have examined the effects of the CYP3A4 inhibitors erythromycin and ketoconazole and the CYP1A2 inhibitor fluvoxamine on the N-deethylation, i.e. formation of monoethylglycinexylidide (MEGX), and 3-hydroxylation of lidocaine by human liver microsomes. The experiments were carried out at lidocaine concentrations of 5 microM (clinically relevant concentration) and 800 microM. The formation of both MEGX and 3-hydroxylidocaine was best described by a two-enzyme model. At 5 microM of lidocaine, fluvoxamine was a potent inhibitor of the formation of MEGX (IC50 1.2 microM). Ketoconazole and erythromycin also showed an inhibitory effect on MEGX formation, but ketoconazole (IC50 8.5 microM) was a much more potent inhibitor than erythromycin (IC50 200 microM). At 800 microM of lidocaine, fluvoxamine (IC50 20.7 microM) and ketoconazole (IC50 20.4 microM) displayed a modest inhibitory effect on MEGX formation, whereas erythromycin was a weak inhibitor (IC50 >250 microM). The 3-hydroxylation of lidocaine was potently inhibited by fluvoxamine at both lidocaine concentrations (IC50 0.16 microM at 5 microM and 1.8 microM at 800 microM). Erythromycin and ketoconazole showed a clear inhibitory effect on the 3-hydroxylation of lidocaine at 5 microM of lidocaine (IC50 9.9 microM and 13.9 microM, respectively), but did not show a consistent effect at 800 microM of lidocaine (IC50 >250 microM and 75.0 microM, respectively). Although further studies are needed to elucidate the role of distinct CYP enzymes in the biotransformation of lidocaine in humans, the findings of this study suggest that while both CYP1A2 and CYP3A4 are involved in the metabolism of lidocaine by human liver microsomes, CYP1A2 is the more important isoform at clinically relevant lidocaine concentrations.

Midazolam alpha-hydroxylation by human liver microsomes in vitro: inhibition by calcium channel blockers, itraconazole and ketoconazole

The inhibitory effects of five calcium channel blockers (diltiazem, isradipine, mibefradil, nifedipine and verapamil) and three azole antifungal agents (itraconazole, hydroxyitraconazole and ketoconazole) on the alpha-hydroxylation of midazolam, a probe drug for CYP3A4-mediated interactions in humans, were studied in vitro using human liver microsomes. IC50 and Ki values were determined for each inhibitor. The kinetics of the formation of alpha-hydroxymidazolam were best described by simple Michaelis-Menten kinetics. The estimated values of Vmax and Km were 696 pmol min.-(1) mg(-1) and 7.46 micromol l(-1), respectively. All the compounds studied inhibited midazolam alpha-hydroxylation activity in a concentration-dependent manner, but there were marked differences in their relative inhibitory potency. Ketoconazole was the most potent inhibitor of midazolam alpha-hydroxylation (IC50 0.12 micromol l (-1)), being 10 times more potent than itraconazole (IC50 1.2 micromol l(-1)). The inhibitory effect of hydroxyitraconazole (IC50 2.3 micromol l (-1) was almost as large as that of itraconazole. Among the calcium channel blockers, mibefradil was the most potent inhibitor of the alpha-hydroxylation of midazolam, with an IC50 value (1.6 micromol l (-1)) similar to that of itraconazole. The other calcium channel blockers were much weaker inhibitors than mibefradil: verapamil exhibited a modest inhibitory effect with an IC50 of 23 micromol l(-1), while isradipine, nifedipine and diltiazem, with IC50 values ranging from 57 to >100 micromol l (-1), were weak inhibitors. This rank order of potency against the alpha-hydroxylation Qf midazolam was verified by the Ki values. With the exception of diltiazem, these in vitro results conform with the observed interaction potential of these agents with midazolam and many other CYP3A4 substrates in vivo in man.

Mibefradil but not isradipine substantially elevates the plasma concentrations of the CYP3A4 substrate triazolam

BACKGROUND

The calcium channel blockers mibefradil and isradipine inhibit CYP3A4 in vitro. However, their in vivo inhibitory effects on CYP3A4 are not known in detail, although mibefradil was recently withdrawn from the market because of serious drug interactions.

METHODS

The effects of mibefradil and isradipine on the pharmacokinetics and pharmacodynamics of oral triazolam, a model substrate of CYP3A4, were studied in a randomized, double-blind crossover study with three phases. Nine healthy subjects took 50 mg mibefradil, 5 mg isradipine, or placebo orally once a day for 3 days. On day 3, each subject received a single 0.25 mg oral dose of triazolam. Thereafter, blood samples were collected up to 18 hours, and pharmacodynamic effects of triazolam were measured up to 8 hours.

RESULTS

Mibefradil increased the total area under the plasma triazolam concentration-time curve [AUC(0 - infinity)] 9-fold compared with placebo (P < .001). The peak plasma concentration of triazolam was increased 1.8-fold (3.4+/-0.1 ng/mL versus 1.8+/-0.2 ng/mL [mean +/- SEM]; P < .001), and the elimination half-life (t 1/2) was increased 4.9-fold (18.5+/-1.9 hours versus 4.0+/-0.5 hours; P < .001) by mibefradil. In addition, mibefradil was associated with increased pharmacodynamic effects of triazolam. In contrast to mibefradil, isradipine reduced the AUC(0 - infinity) and t 1/2 of triazolam by about 20% (P < .05) and had no significant effects on the pharmacodynamics of triazolam.

CONCLUSION

Mibefradil but not isradipine markedly increases the plasma concentrations of triazolam and thereby enhances and prolongs its pharmacodynamic effects, consistent with potent inhibition of CYP3A4.

[Study on correlation between in vivo and in vitro tests of biomaterials--correlation between leukocyte chemotaxis test and muscular implant test in rabbits]

The purpose of this study was to investigate the correlation between the results of in vivo and in vitro tests of biomaterials. With muscular implant test and leukocyte chemotaxis test, the levels of tissue toxicity of seven biomaterials were evaluated. The samples with high-level toxicity showed weak leukocyte chemotaxis, which would influence the anti-inflammatory reaction to foreign bodies. By the method of Spearman rank correlation, the coefficient was between 0.89286-0.98198 indicating that the correlation of the two tests is excellent.

[Antagonistic effects of metallothionein on genetic damage caused by gamma-rays and mitomycin C]

OBJECTIVE

To study the antagonistic effects of metallothionein (Zn-MT)on genetic damage caused by gamma-rays and mitomycin C (MMC) in the liver of rabbits.

METHODS

Micronucleus test and DNA strand breaks were determined in vitro and in vivo with single-cell gel electrophoresis assay to observe the effects of Zn-MT on the micronucleus formation and cleavage of DNA chain before and after gamma-rays radiation and MMC treatment.

RESULTS

A dose of 664 microg/kg of Zn-MT could inhibit micronucleus formation in the bone marrow of the mice induced by 5 Gy gamma-rays radiation (P < 0.05). Concentrations of 10 and 50 microg/ml Zn-MT could antagonize the increase in bimicronucleus frequency in g12 cells induced by 1 and 3 Gy gamma-rays radiation and 0.3 microg/ml MMC treatment (P < 0.05 or P < 0.01). A dose of 50 microg/ml Zn-MT could reduce the DNA single strand breaks caused by 1 Gy gamma-rays radiation, but without statistical significance (P > 0.05).

CONCLUSION

Zn-MT could antagonize the genetic damage to certain extent in the liver of the rabbits caused by gamma-rays radiation and MMC treatment.

A novel therapy for colitis utilizing PPAR-gamma ligands to inhibit the epithelial inflammatory response

Peroxisome proliferator-activated receptor gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily originally shown to play a critical role in adipocyte differentiation and glucose homeostasis, has recently been implicated as a regulator of cellular proliferation and inflammatory responses. Colonic epithelial cells, which express high levels of PPAR-gamma protein, have the ability to produce inflammatory cytokines that may play a role in inflammatory bowel disease (IBD). We report here that PPAR-gamma ligands dramatically attenuate cytokine gene expression in colon cancer cell lines by inhibiting the activation of nuclear factor-kappaB via an IkappaB-alpha-dependent mechanism. Moreover, thiazolidinedione ligands for PPAR-gamma markedly reduce colonic inflammation in a mouse model of IBD. These results suggest that colonic PPAR-gamma may be a therapeutic target in humans suffering from IBD.

Linear modeling of mRNA expression levels during CNS development and injury

Large-scale gene expression data sets are revolutionizing the field of functional genomics. However, few data analysis techniques fully exploit this entirely new class of data. We present a linear modeling approach that allows one to infer interactions between all the genes included in the data set. The resulting model can be used to generate interesting hypotheses to direct further experiments.

GABAA receptor subunit composition and functional properties of Cl- channels with differential sensitivity to zolpidem in embryonic rat hippocampal cells

Using flow cytometry in conjunction with a voltage-sensitive fluorescent indicator dye (oxonol), we have identified and separated embryonic hippocampal cells according to the sensitivity of their functionally expressed GABAA receptors to zolpidem. Immunocytochemical and RT-PCR analysis of sorted zolpidem-sensitive (ZS) and zolpidem-insensitive (ZI) subpopulations identified ZS cells as postmitotic, differentiating neurons expressing alpha2, alpha4, alpha5, beta1, beta2, beta3, gamma1, gamma2, and gamma3 GABAA receptor subunits, whereas the ZI cells were neuroepithelial cells or newly postmitotic neurons, expressing predominantly alpha4, alpha5, beta1, and gamma2 subunits. Fluctuation analyses of macroscopic Cl- currents evoked by GABA revealed three kinetic components of GABAA receptor/Cl- channel activity in both subpopulations. We focused our study on ZI cells, which exhibited a limited number of subunits and functional channels, to directly correlate subunit composition with channel properties. Biophysical analyses of GABA-activated Cl- currents in ZI cells revealed two types of receptor-coupled channel properties: one comprising short-lasting openings, high affinity for GABA, and low sensitivity to diazepam, and the other with long-lasting openings, low affinity for GABA, and high sensitivity to diazepam. Both types of channel activity were found in the same cell. Channel kinetics were well modeled by fitting dwell time distributions to biliganded activation and included two open and five closed states. We propose that short- and long-lasting openings correspond to GABAA receptor/Cl- channels containing alpha4beta1gamma2 and alpha5beta1gamma2 subunits, respectively.

Glutamate acting at NMDA receptors stimulates embryonic cortical neuronal migration

During cortical development, embryonic neurons migrate from germinal zones near the ventricle into the cortical plate, where they organize into layers. Mechanisms that direct neuronal migration may include molecules that act as chemoattractants. In rats, GABA, which localizes near the target destination for migrating cortical neurons, stimulates embryonic neuronal migration in vitro. In mice, glutamate is highly localized near the target destinations for migrating cortical neurons. Glutamate-induced migration of murine embryonic cortical cells was evaluated in cell dissociates and cortical slice cultures. In dissociates, the chemotropic effects of glutamate were 10-fold greater than the effects of GABA, demonstrating that for murine cortical cells, glutamate is a more potent chemoattractant than GABA. Thus, cortical chemoattractants appear to differ between species. Micromolar glutamate stimulated neuronal chemotaxis that was mimicked by microM NMDA but not by other ionotropic glutamate receptor agonists (AMPA, kainate, quisqualate). Responding cells were primarily derived from immature cortical regions [ventricular zone (vz)/subventricular zone (svz)]. Bromodeoxyuridine (BrdU) pulse labeling of cortical slices cultured in NMDA antagonists (microM MK801 or APV) revealed that antagonist exposure blocked the migration of BrdU-positive cells from the vz/svz into the cortical plate. PCR confirmed the presence of NMDA receptor expression in vz/svz cells, whereas electrophysiology and Ca2+ imaging demonstrated that vz/svz cells exhibited physiological responses to NMDA. These studies indicate that, in mice, glutamate may serve as a chemoattractant for neurons in the developing cortex, signaling cells to migrate into the cortical plate via NMDA receptor activation.

Mobilization of heavy metals from Le An River sediment

The release of sediment-bound heavy metals can have a significant influence on river water quality. Generally speaking, variations of pH and oxygen are among the most important chemical factors that affect the mobility of sediment-bound metals. Recent research has indicated that sulfide, measured as acid-volatile sulfide (AVS), is an important partitioning component of heavy metals. We determined the metal release potential of sediments from the Le An River which receives drainage from a major copper mining operation. We found that the in-situ Cu, Pb, Zn, Cd and As concentrations of the Le An River sediments below the mine are much higher than are the global background values, but that Ni was not elevated. There is potential for mobilization of bound metals to the overlying water, the order of metal release ratio in terms of pH dependencies is Zn > Cu > Cd approximately Pb. Sulfide is not a major binding component for metals in Le An River sediment. It is more likely that the iron and manganese oxides are the most important metal binding components in the sediments of the Le An River.

[Evaluation on cytotoxicity of gallium alloy]

Cytotoxicity is an important indicator to the biocompatibility of biomaterials. In this study, the cytotoxicity of Gallium alloy was evaluated by the method of cell relative growth rate in vitrousing L-929 mouse fibroblast. The cell relative growth rate of Gallium alloy was the absorbency ratio between the solution of Gallium alloy and negative control. The relative growth rates of Gallium aloy were converted into the scores of cytotoxicity. It was found from the results that Gallium alloy had no cytotoxicity.

[Effects of Squama manitis on cardiac systolic function and platelet aggregation]

OBJECTIVE

To study the effect of Squama Manitis(S. M.) on cardiac function and platelet aggregation in vitro.

METHOD

Isolated working rat hearts were prepared, and cardiac performance was measured before and after adding S. M. in the Krebs-Hensleit(K-H) perfusion buffer. Controls with K-H buffer were also investigated. Rich platelet plasma and Poor platelet plasma were centrifuged from the blood of 15 patients with coronary heart disease. Each sample was divided into three parts for use by three groups: control, group of S. M. and group of aspirin. Platelet aggregation was stimulated by adenosine diphosphate.

RESULT

LVSP, +dP/dtmax and CO of isolated working rat hearts were significantly increased after treating with S. M. liquor. S. M. had no obvious effect on -dP/dtmax and LVEDP. These parameters did not change significantly in the control. Percentages of platelet aggregation were significantly lower in the group of S. M. and the group of aspirin as compared with the control.

CONCLUSION

S. M. increases cardiac systolic function, has positive inotropic effect on myocardium and inhibits platelet aggregation.

The glycogen phosphorylase-2 promoter binding protein in Dictyostelium is replication protein A

During Dictyostelium development, glycogen degradation is a crucial event that provides glucose monomers used in the synthesis of the essential structural components for cellular differentiation. The product of the developmentally regulated glycogen phosphorylase-2 gene (gp2) catalyzes the degradation. DNA-binding proteins were found to bind to a regulatory site of the gp2 gene in a stage-dependent pattern. Gel-shift analysis of undifferentiated amoebae cell extract revealed a protein migrating at 0.40 Rf, while 17 hour differentiated cell extract produced a species migrating at 0.32 Rf. Both the 0.32 and 0.40 Rf proteins were purified and found to consist of three subunits of 18, 35 and 62 kDa (for 0.40 Rf) or 81 kDa (for 0.32 Rf). Data base searches identified the protein as the Dictyostelium homologue of replication protein A (DdRPA). Amino acid sequence analysis showed identity between the 62 and 81 kDa subunits. Incubation of cell-free extracts under appropriate conditions at low pH, resulted in conversion of the 81 kDa to the 62 kDa subunit. Northern blot analysis revealed that the levels of expression of the large subunit of DdRPA were constant throughout differentiation and the size of the mRNA was the same at all stages of development. The results raise the possibility that pH induced post-translational modifications of DdRPA are involved in events that halt cell proliferation and induce differentiation in Dictyostelium.

Intestinal inflammation reduces expression of DRA, a transporter responsible for congenital chloride diarrhea

The pathogenesis of diarrhea in intestinal inflammatory states is a multifactorial process involving the effects of inflammatory mediators on epithelial transport function. The effect of colonic inflammation on the gene expression of DRA (downregulated in adenoma), a chloride-sulfate anion transporter that is mutated in patients with congenital chloridorrhea, was examined in vivo as well as in an intestinal epithelial cell line. DRA mRNA expression was diminished five- to sevenfold in the HLA-B27/beta2m transgenic rat compared with control. In situ hybridization showed that DRA, which is normally expressed in the upper crypt and surface epithelium of the colon, was dramatically reduced in the surface epithelium of the HLA-B27/beta2m transgenic rat, the interleukin-10 (IL-10) knockout mouse with spontaneous colitis, and in patients with ulcerative colitis. Immunohistochemistry demonstrated that mRNA expression of DRA reflected that of protein expression in vivo. IL-1beta reduced DRA mRNA expression in vitro by inhibiting gene transcription. The loss of transport function in the surface epithelium of the colon by attenuation of transporter gene expression, perhaps inhibited at the level of gene transcription by proinflammatory cytokines, may play a role in the pathogenesis of diarrhea in colitis.

[Investigation of HGV infection in various populations in Guangxi]

In order to understand the situation of HGV infection in various populations in Liuzhou prefecture of Guangxi, Zhuangzu Autonomous Region, and also to compare the HGV, HBV, HCV infections between intravenous drug abusers and healthy persons (those for physical examination, the same below), the anti-HGV, -HCV and HBVM (HBsAg, HBsAb, HBeAg, HBeAb, HBcAb) were detected by ELA and, besides, tested further the 20 anti-HGV seropositive cases for HGV-RNA by RT-nPCR. The results showed that in the populations tested, the HGV seropositive rate was 9.8% (106/1079), separately they were 23.8% (5/21), 21.1% (23/109), 12.5% (6/48), 12.0% (6/50), 12.0% (20/166), 9.3% (3/32), 8.2% (34/413), 4.3% (6/140), and 3.0% (3/100) in liver cirrhosis, intravenous drug abusers, repeated blood and blood products transfused patients, hepatocellularcarcinoma patients, viral hepatitis, haemodialysis patients, healthy persons, paid blood donors and healthy pregnant women respectively. In intravenous drug abusers, the HGV, HBV, HCV infection rate were 21.2% (23/109), 75.3% (82/109) and 7.3% (8/109) respectively, while they were 8.2% (9/109), 20.1% (22/109), and 1.8% (2/109) in healthy persons respectively. These data showed that Liuzhou prefecture of Guangxi was HGV high epidemic area, HGV infection rate was higher in populations of intravenous drug abusers, viral hepatitis, liver cirrhosis and repeatedly blood and blood products transfused patients, even in pregnant women the HGV infection also occurred. There was a significant difference of HGV, HBV, HCV infection rates between intravenous drug abusers and healthy persons (P < 0.005).

Corrosion resistance and ion dissolution of titanium with different surface microroughness

In vitro corrosion resistance and ion dissolution of commercial pure titanium with different surface microroughness are studied adopting constant potential meter and atomic absorption spectroscopy. In terms of the surface roughness, titanium samples are divided into 5 groups: smooth surface, machining surface, 2 different microroughness surfaces and macrorough surface. Each group contains three category samples under different treatments: natural oxidation (24 h exposure to air), oxidation under 400 degrees C (400 degrees C, 45 min thermal oxidation), oxidation under 700 degrees C (700 degrees C, 45 min thermal oxidation). In Hanks corrosion media, comparative studies through constant potential anode polarization curves and titanium release rates of the 5 groups of Ti samples demonstrates that oxidation under 400 degrees C best increase corrosion resistance and decrease ion release sharply, oxidation under 700 degrees C is better than natural oxidation. Ti samples with a different surface roughness all have good corrosion resistance and their corrosion resistance drop with the raising of surface roughness. Comparing with macrorough surface and machining surface, microrough surfaces have better corrosion resistance and a lower ion release rate which are similar to those of smooth surfaces. Moreover, the corrosion resistance of machining surface Ti is the lowest. It is hypothesized that surface treatment methods such as surface thermal oxidation, surface aging and so on will improve the corrosion resistance and decrease the ion release rate of rough surface effectively by increasing the thickness of surface protection film, improving its structural uniformity and facilitating the formation of ordered, compact surface protection film.

The amiloride-sensitive epithelial sodium channel alpha-subunit is transcriptionally down-regulated in rat parotid cells by the extracellular signal-regulated protein kinase pathway

Previous studies have shown that an inducible Raf-1 kinase protein, DeltaRaf-1:ER, activates the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK)-signaling pathway, which is required for the transformation of the rat salivary epithelial cell line, Pa-4. Differential display polymerase chain reaction was employed to search for mRNAs repressed by DeltaRaf-1:ER activation. Through this approach, the gene encoding the alpha-subunit of the amiloride-sensitive epithelial sodium channel (alpha-ENaC) was identified as a target of activated Raf-1 kinases. alpha-ENaC down-regulation could also be seen in cells treated with 12-O-tetradecanoyl-1-phorbol-13-acetate (TPA), indicating that the repression of steady-state alpha-ENaC mRNA level was dependent upon the activity of protein kinase C, the target of TPA, as well. Pretreatment of cells with a specific inhibitor of the ERK kinase pathway, PD 98059, markedly abolished the down-regulation of alpha-ENaC expression, consistent with the hypothesis that the ERK kinase-signaling pathway is involved in TPA-mediated repression. Moreover, through the use of transient transfection assays with alpha-ENaC-reporter and activated Raf expression construct(s), we provide the first evidence that activation of the ERK pathway down-regulates alpha-ENaC expression at the transcriptional level. Elucidating the molecular programming that modulates the expression of the alpha-subunit may provide new insights into the modulation of sodium reabsorption across epithelia.

[A kind of method for measuring absorbance spectrum with dual beam light and one detector]

A kind of method of measuring spectral transmittivity with source compensated is introduced in this paper. It detects simultaneously intensity of source and transmission light with dual light road and one detector by means of the characters of selective frequence amplifing and coherent detection of a lock-in amplifier. The experimental result shows that the method is excellent on overcoming shake of a source and improving signal-to-noise ratio.

The NH2 terminus of the herpes simplex virus type 1 regulatory protein ICP0 contains a promoter-specific transcription activation domain

The transcriptional program of herpes simplex virus is regulated by the concerted action of three immediate-early (alpha) proteins, ICP4, ICP27, and ICP0. The experiments described in this study examine the role of the acidic amino terminus (amino acids 1 to 103) of ICP0 in gene activation. When tethered to a DNA binding domain, this sequence activates transcription in the yeast Saccharomyces cerevisiae. Deletion of these amino acids affects the ability of ICP0 to activate alpha-gene promoter reporters in transient expression assays, while it has little or no effect on a beta- and a gamma-gene reporter in the same assay. Viruses that express the deleted form of ICP0 (ICP0-NX) have a small-plaque phenotype on both Vero cells and the complementing cell line L7. Transient expression and immunofluorescence analyses demonstrate that ICP0-NX is a dominant negative form of ICP0. Immunoprecipitation of ICP0 from cells coinfected with viruses expressing ICP0-NX and ICP0 revealed that ICP0 oligomerizes in infected cells. These data, in conjunction with the finding that ICP0-N/X is dominant negative, provide both biochemical and genetic evidence that ICP0 functions as a multimer in infected cells.

[Research of eximer laser-excited fast speed spectrochemical analysis]

Experimental method including XeCl eximer Laser-excited, optical multichannel analyzer (OMA) combined with the simultaneous spectrum widen technique was introduced in this paper. We programed data acquisition software and tested alloy-steel sample. The acquisition result of 150nm simultaneous spectrum was showed. The charaterics and significances of our research were discussed.

[Application of simple OMA system for rapid spectrochemical quantitative analysis to steel sample composition]

In this paper, the experimental method and characteristic of a simple optical multichannel analyzer (OMA) system used for rapid spectrochemical quantitative analysis was introduced. Mangangese and chromium contents in different steel samples were measured. The reliability of experimental results was discussed according to the mathematical statistics theory. Analytical results were compared with those of chemical and ICP analysis.

[An observation on antiviral effect of IFN--alpha N1 (Wellferon) in patients with chronic hepatitis B]

In order to observe the antiviral effect of IFN-alpha N1(Wellferon, British Glaxowellcome Company) on CHB, each 50 cases of CHB were selected as the therapy group and the control group. The patients in the therapy group were administrated with 3MU of IFN-alpha N1 once a day for one week, and then 3MU of IFN-alpha N1 three times weekly for 11-23 weeks, whereas the patients in the control group did not receive any antiviral treatment. At 3 months, the serum alanine transaminsae(ALT) was decreased to normal level in 84%(42/50) cases of the therapy group, while only in 46% (23/50) cases of the control group (P < 0.01). The negative seroconversion rate of HBeAg was 56.7% (17/30) and 10.8% (4/37), of HBV DNA was 36.4%(12/33) and 5.9% (1/17) in therapy and control groups respectively. There was obvious difference in two groups. The results suggest that IFN-alpha N1 is satisfying antiviral drug for CHB patients or patients non-responsive to other IFNs.

Effect of baffles and a louvered bypass on the airflow and the convective patterns of contaminant inside a fume hood

Various numerical predictions are given for the containment testing of fume hoods with internal baffles of different size and at different locations and with a louvered bypass. The numerical predictions were compared with experimental data and a fairly good agreement for the air velocity was found, although there was only qualitative agreement for the concentration of the contaminant. It was found that the level of contaminant leakage at the working aperture depended not only on the size of the recirculating airflow behind the fume hood sash but also on the blockage caused by the baffles inside the fume hood near the exhaust duct. Finally, some new suggestions for the design of the fume hood have been proposed. However, before implementing these suggestions it is essential that either experimental testing be performed, or the cost-effective alternative of using numerical predictions for containment testing, to determine accurately the level of contaminant leakage from the working aperture.

[Effect of -6 degrees bed-rest on T-lymphocyte proliferation and cytokines production in human]

In this study, the effect of -6 degrees head-down bed-rest on proliferation of T lymphocyte stimulated by phytohemagglutinin, a kind of polyclone T cell activators and cytokines production were observed. The results showed: after 2 d bed-rest, proliferation of T lymphocyte stimulated by phytohemagglutinin decreased significantly; the activity of interleukin-2 trended to decrease; the expression of interleukin-2 receptor tended to increase; the production of interleukin-6 decreased significantly. After 6 d bed-rest, T lymphocyte proliferation restored to normal; the activity of interleukin-2 and expression of interleukin-2 receptor had no change; the production of interleukin-6 decreased significantly. This result demonstrated that -6 degrees bed-rest can decrease T lymphocyte proliferation function, and this decrease may be caused by the reduction of cytokines secretion.

Large-scale temporal gene expression mapping of central nervous system development

We used reverse transcription-coupled PCR to produce a high-resolution temporal map of fluctuations in mRNA expression of 112 genes during rat central nervous system development, focusing on the cervical spinal cord. The data provide a temporal gene expression "fingerprint" of spinal cord development based on major families of inter- and intracellular signaling genes. By using distance matrices for the pair-wise comparison of these 112 temporal gene expression patterns as the basis for a cluster analysis, we found five basic "waves" of expression that characterize distinct phases of development. The results suggest functional relationships among the genes fluctuating in parallel. We found that genes belonging to distinct functional classes and gene families clearly map to particular expression profiles. The concepts and data analysis discussed herein may be useful in objectively identifying coherent patterns and sequences of events in the complex genetic signaling network of development. Functional genomics approaches such as this may have applications in the elucidation of complex developmental and degenerative disorders.

Cluster analysis and data visualization of large-scale gene expression data

The discovery of any new gene requires an analysis of the expression context for that gene. Now that the cDNA and genomic sequencing projects are progressing at such a rapid rate, high throughput gene expression screening approaches are beginning to appear to take advantage of that data. We present a strategy for the analysis for large-scale quantitative gene expression measurement data from time course experiments. Our approach takes advantage of cluster analysis and graphical visualization methods to reveal correlated patterns of gene expression from time series data. The coherence of these patterns suggests an order that conforms to a notion of shared pathways and control processes that can be experimentally verified.