Quantitative structural and biochemical analyses of tight junction dynamics following exposure of epithelial cells to house dust mite allergen Der p 1

BACKGROUND

House dust mite allergen Der p 1 is a cysteine peptidase. Previously, we have suggested that the proteolytic activity of this allergen may contribute to asthma by damaging the barrier formed by the airways epithelium.

OBJECTIVE

The present study applied novel techniques to compare changes in permeability with quantitative events in tight junctions (TJs) and desmosomes (DMs) of epithelial cells exposed to Der p 1.

METHODS

Confluent monolayers of Madin-Darby canine kidney (MDCK) and 16HBE14o-human bronchial epithelial cells were used as experimental models. Permeability was estimated from mannitol clearance. Digital imaging with quantification of TJs and DMs was achieved by fluorescent antibody staining and 2-photon molecular excitation microscopy (2PMEM). Biochemical changes in TJs were studied by immunoblotting, radiolabelling and immunoprecipitation.

RESULTS

Der p 1 caused a time-dependent breakage of TJs and reduction in their content of the protein ZO-1. Reduction in ZO-1 immunofluorescence at TJs occurred with a small increase in the amount of diffuse, cytoplasmic immunoreactive ZO-1 staining. Morpho-logical changes in TJs occurred in synchrony with increases in epithelial permeability. DM puncta increased both in size and intensity of staining. Immunoblotting demonstrated that the disruption of TJ morphology was associated with cleavage of ZO-1 and occludin. Cells recovered from allergen exposure by de novo synthesis of occludin.

CONCLUSION

Der p 1 could contribute to sensitization and allergic responses by degrading the function of the airway epithelial barrier.

[Construction and transient expression of an Ala 737-->Glu mutant of vWF]

OBJECTIVE

To study the functional change of an Ala737-->Glu substitution mutant of vWF and the molecular pathological mechanism of this mutant in the type 2A vWD.

METHODS

The expression plasmid pSVvWF containing full-length cDNA of vWF was used to site direct mutagenesis by polymerase chain reaction (PCR) and transitorily expressed in the COS-7 cells, vWF: Ag in the supernatant and the cell lysate between wild type and pSVAla737Glu vWF were measured. vWF polymers of the platelet of the patient with the mutation and response to DDAVP treatment of the patient were observed.

RESULTS

vWF: Ag level of pSVAla 737Glu vWF was 76.4% and 98.8% of the wild types in the supernatant and cell lysate, respectively. The polymer pattern of extracellular pSVAla737Glu vWF was indistinguishable from that of the wild type, containing all kinds of molecular weight. Increased vWF antigen levels was observed in the patients after DDAVP treatment.

CONCLUSION

This mutant did not change the assembly and secretion of vWF. The mutant of vWF Ala737-->Glu resulted in Group II type 2A vWD.

Chiral separation of amino acids and peptides by capillary electrophoresis

Chiral separation of amino acids and peptides by capillary electrophoresis (CE) is reviewed regarding the separation principles of different approaches, advantages and limitations, chiral recognition mechanisms and applications. The direct approach details various chiral selectors with an emphasis on cyclodextrins and their derivatives, antibiotics and chiral surfactants as the chiral selectors. The indirect approach deals with various chiral reagents applied for diastereomer formation and types of separation media such as micelles and polymeric pseudo-stationary phases. Many derivatization reagents used for high sensitivity detection of amino acids and peptides are also discussed and their characteristics are summarized in tables. A large number of relevant examples is presented illustrating the current status of enantiomeric and diastereomeric separation of amino acids and peptides. Strategies to enhance the selectivity and optimize separation parameters by the application of experimental designs are described. The reversal of enantiomeric elution order and the effects of organic modifiers on the selectivity are illustrated in both direct and indirect methods. Some applications of chiral amino acid and peptide analysis, in particular, regarding the determination of trace enantiomeric impurities, are given. This review selects more than 200 articles published between 1988 and 1999.

A recombinant antibody-targeted plasminogen activator with high affinity for activated platelets increases thrombolytic potency in vitro and in vivo

To increase thrombolytic specificity of urokinase (uPA), we engineered a recombinant chimeric plasminogen activator SZ51Hu-scuPA, which consists of a humanized monoclonal antibody (SZ-51Hu) specifically against P-selectin on activated human platelet and a single-chain urokinase (scuPA). The cDNA, encoding scuPA amino acids 1-411, was inserted in 5' end to 3' end orientation immediately after the CH3 of SZ-51Hu heavy-chain sequence in the expression vector alphaLys30. The resulting construct alphaLys30-SZ51VH/Hu-scuPA was used to transfect into SP2/0 murine myeloma cell line, which was pretransfected with SZ51Hu light chain. The fusion protein SZ51Hu-scuPA was expressed at 5 mg/L in the supernatant of cell culture. The fusion protein purified by affinity chromatography had a molecular weight of 160 kDa with fibrinolytic activity of 39,000 IU/mg and its affinity to activated human platelet was 67% of the parent murine mAb SZ-51. The thrombolytic property of the fusion protein was first characterized in an in vitro system, which consists of a 125I-fibrin-labeled human plasma clot containing different concentrations of human platelets suspended in citrated human plasma. Fifty percent lysis was reached with SZ51Hu-scuPA in 1 hour at a concentration of 20 IU/mL or in 2 hours at a concentration of 10 IU/ mL, which was much faster than uPA at the same concentration. The maximal lysis of the clots by SZ51Hu-scuPA was 4.1 to 8.4 times more potent than that by uPA. The fusion protein was further characterized in the hamster pulmonary embolism model with clots prepared from fresh platelet-rich human plasma containing 125I-labeled fibrinogen. The thrombolytic activity of SZ51-scuPA was 3.9 times more potent than that of uPA at 2,000 IU/kg in this model. Almost no significant fibrinogen breakdown was observed either in vitro and in vivo.

A global compositional complexity measure for biological sequences: AT-rich and GC-rich genomes encode less complex proteins

Different local regions of natural amino acid or nucleotide sequences show remarkable heterogeneity in residue composition, reflecting diversity in evolutionary history and physiochemical constraints. Compositional complexity measures are helpful for describing and understanding this variegation. Motivated by some open problems in comparative genomics and protein folding, we have developed a new 'global' compositional complexity measure, G1, which overcomes a crucial limitation of earlier methods. The 'local' measures used in previous research resemble entropy functions and are inherently dependent on an underlying probability distribution. Local measures cannot rigorously compare complexity across sequences of substantially different size, because real sequences show very irregular heterogeneity and do not have the necessary ergodicity in scaling and asymptotic properties. G1 is a member of a new class of scale-independent, distribution-independent complexity functions. For a sequence S of length L on an N-letter alphabet, G1 is derived from ratios in the integer partition lattice, P¿L,N¿ of L with N parts, where the elements of P¿L,N¿ are the state vectors of S, (n1, n2,..., nN), ranked by an order principle. We present theorems and proofs relating to the metric properties of G1 and its relationship to other state-vector-dependent compositional complexity functions, together with a fully-efficient O(L) algorithm to compute G1. The distributions of G1 were calculated for the entire sets of translated proteins encoded by extensively sequenced genomes. The results establish the existence of a clear evolutionary principle, common to bacteria, archaea and eukaryotes, that the proteins encoded by more extreme AT-rich and GC-rich genomes have generally lower compositional complexity than those of more typical organisms.

[The effect of surface structure on the photoluminescence of SnO2 nanoparticles in hydrosols and organosols]

In this paper, we report the optical properties of SnO2 semiconductor nanoparticles in hydrosols and those of SnO2 semiconductor nanoparticles in organosols in which the surfaces of the particles are coated by a layer of organic surfactant molecules. The photoluminescence spectra of SnO2 semiconductor nanoparticles in the hydrosols and organosols in different conditions were measured and discussed. We conclude that the surface structure of the SnO2 semiconductor nanoparticles affects their optical properties strongly. The oxygen deficiencies on the surface of SnO2 semiconductor nanoparticles play an important role in the optical properties. The surface modification of the particles effectively removes the surface defects of the particles and enhances the intensity of luminescence.

Some factors affecting enantiomeric impurity determination by capillary electrophoresis using ultraviolet and laser-induced fluorescence detection

The key factors influencing enantiomer trace determination were investigated; these include resolution capillary diameter, limit of detection, linear range and type of detection. Chiral reagents, (+)- and (-)-1-(9-fluorenyl)ethyl chloroformate (FLEC), were employed as probes to demonstrate the influence of the variables. In order to find the best resolution, separation variables were optimized in both capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) modes by the application of factorial design experiments. A highly efficient chiral separation of the (+/-)-FLEC, derivatized with nonchiral amino acids, was achieved when using gamma-cyclodextrin as the chiral selector. The benefits of using a small diameter capillary for direct determination of both (+) and (-)-FLEC impurity (0.05-0.1% area/area) were demonstrated using UV detection and applying a sample stacking condition. A frequency-doubled argon ion laser (244 nm) was used as light source for laser-induced fluorescence (LIF) detection. Excitation light was provided by means of an optical fiber directed into the Hewlett Packard 3D capillary cartridge. The signals from UV and LIF were monitored simultaneously. The application of LIF detection greatly improved sensitivity and linear range. Further, as a consequence of the increased sensitivity, sample loading could be decreased, which led to an improvement of separation efficiency. Direct determination of 0.005% impurity could be achieved within the linear range.

Overexpression of retinoic acid receptor beta in head and neck squamous cell carcinoma cells increases their sensitivity to retinoid-induced suppression of squamous differentiation by retinoids

Nuclear retinoic acid receptor beta(RARbeta) expression is suppressed in many head and neck squamous cell carcinomas (HNSCCs), and an inverse relationship was found between squamous differentiation and RARbeta expression in such cells. To investigate the role of RARbeta in HNSCC growth and differentiation, we transfected a retroviral RARbeta2 expression vector (LNSbeta) into HNSCC SqCC/Y1 cells, which do not express endogenous RARbeta but do express RARalpha, RARgamma, and retinoid X receptors. Transfected clones expressing RARbeta2 mRNA and protein exhibited enhanced sensitivity to the suppressive effects of all-trans-retinoic acid (ATRA) on squamous differentiation compared with cells transfected with the LNSX vector only; transglutaminase type I level was suppressed after a 3-day treatment with 10(-10) M ATRA in four of five LNSbeta clones, whereas it was not suppressed in LNSX cells even by 10(-6) M ATRA. Similarly, cytokeratin 1 mRNA level was more suppressed in ATRA-treated LNSbeta clones than it was in LNSX cells. This effect was independent of transrepression of activator protein-1. None of the LNSbeta-transfected clones showed an increased growth inhibition by ATRA, 9-cis-retinoic acid, or the synthetic retinoid 6-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-2-naphthale necarboxylic acid. These findings suggest that, in SqCC/Y1 cells, RARbeta mediates suppression of squamous differentiation by ATRA without enhancing its growth-inhibitory effects.

Der p 1 facilitates transepithelial allergen delivery by disruption of tight junctions

House dust mite (HDM) allergens are important factors in the increasing prevalence of asthma. The lung epithelium forms a barrier that allergens must cross before they can cause sensitization. However, the mechanisms involved are unknown. Here we show that the cysteine proteinase allergen Der p 1 from fecal pellets of the HDM Dermatophagoides pteronyssinus causes disruption of intercellular tight junctions (TJs), which are the principal components of the epithelial paracellular permeability barrier. In confluent airway epithelial cells, Der p 1 led to cleavage of the TJ adhesion protein occludin. Cleavage was attenuated by antipain, but not by inhibitors of serine, aspartic, or matrix metalloproteinases. Putative Der p 1 cleavage sites were found in peptides from an extracellular domain of occludin and in the TJ adhesion protein claudin-1. TJ breakdown nonspecifically increased epithelial permeability, allowing Der p 1 to cross the epithelial barrier. Thus, transepithelial movement of Der p 1 to dendritic antigen-presenting cells via the paracellular pathway may be promoted by the allergen's own proteolytic activity. These results suggest that opening of TJs by environmental proteinases may be the initial step in the development of asthma to a variety of allergens.

[Mutation (Ala737-->Glu) in type 2A von Willebrand disease]

OBJECTIVE

To identify mechanism of molecular pathogenesis and relationship between phenotype and genotype of von Willebrand disease (vWD).

METHODS

Two patients from a family were studied. They were diagnosed as type 2A vWD showing prolonged bleeding time, markedly decreased vWF: Ag and FVIII: C Ag and absence of high and intermediate molecular weight form of von Willebrand factor multimers in plasma. The 28th exon of authenticity vWF gene was obtained by polymerase chain reaction and PAGE and then screened by denaturing gradient electrophoresis (DGGE). The abnormal bands were sequenced.

RESULTS

A heterozygous C-->A transition was identified, resulting in an ala737glu mutation in the A2 domain of the mature vWF subunit.

CONCLUSION

The new mutation will be a tool for the study of the structure and function of vWF.

Different contributions of the hippocampus and perirhinal cortex to recognition memory

Brain regions involved in visual recognition memory, including the hippocampus, have been investigated by measuring differential neuronal activation produced by novel and familiar pictures. Novel and familiar pictures were presented simultaneously, one to each eye, using a paired viewing procedure. Differential neuronal activation was determined using immunohistochemistry for the protein products of c-fos as an imaging technique. The results establish that the regions of the rat brain associated with discriminating the novelty or familiarity of an individual item (such as a single object) differ from those responding to a spatial array of items (such as a scene). Perirhinal cortex and area TE of the temporal lobe are activated significantly more by pictures of novel than of familiar individual objects, but the hippocampus is not differentially activated. In contrast, pictures of novel arrangements of familiar items produce significantly greater activation than familiar arrangements of these items in postrhinal cortex and subfield CA1 of the hippocampus but significantly less activation in the dentate gyrus and subiculum; perirhinal cortex and area TE are not differentially activated. Thus, the hippocampus is importantly involved in processing information essential to recognition memory concerning the relative familiarity of arrangements of items, as needed for episodic memory of scenes, whereas the perirhinal cortex processes such information for individual items.

[Atraumatic restorative treatment fillings and fissure sealants in permanent teeth--a 2-year study]

OBJECTIVE

To study the feasibility of providing Atraumatic Restorative Treatment (ART) in schools and in rural areas in China, and to evaluate the acceptance and effectiveness of the treatment.

METHODS

The study was conducted among 272 grade one students chosen from four different secondary schools in Deyang of Sichuan Province, China. The mean age of the subjects was 12.5 years. 107 boys and 165 girls were found at the baseline examination to have teeth that were suitable for receiving ART fillings or sealants. The treatments were performed within a month using the glass ionomer Ketac-Molar manufactured by ESPE. Evaluation was carried out at 3 months, one year and two years after treatment.

RESULTS

ART fillings were placed in 295 permanent teeth, and the 1-year and 2-year success rates were 95.7% and 91.1% respectively. ART sealants were placed in another 191 permanent teeth, and the 3-month, 1-year and 2-year success rates were 95.2%, 89.1% and 78.8% respectively. The incidence of recurrent caries was very low after two years, which were 2.1% and 0.6% for the fillings and sealants respectively. ART was accepted by the majority of the students.

CONCLUSION

ART is a simple, acceptable technique, and is suitable for widespread adoption in China.

Thermal dose optimization for ultrasound tissue ablation

A formal and general thermal dose optimisation method is developed and tested. Prior methods require brute force searches wherein the temperature and dose distributions must be computed at each iteration by solving the bioheat transfer equation (BHTE) numerically. This is extremely time-consuming and can only be used to compare a few prespecified strategies instead of obtaining a more general optimal result. With the method developed here, dose distribution can be calculated without solving the BHTE numerically. This can be done in a matter of a few minutes compared with many hours. Moreover, general thermal dose optimization can now be performed to find the optimal strength and location of each focus so that an optimal dose distribution is obtained while the specified constraint is satisfied. The algorithm developed here consists of a closed-form solution to the BHTE, a Gaussian model for parameterizing a temperature distribution created by a power deposition pattern, and a two-step optimization technique for obtaining the model parameters that optimize the thermal dose distribution. Several examples are given to demonstrate the effectiveness of the algorithm and its robustness under different initial conditions and under assumptions of different sizes of the target region and different numbers of foci. The algorithm developed here provides an efficient and effective tool for treatment planning in ultrasound tissue ablation.

Highly efficient separation of isomeric epoxy fatty acids by micellar electrokinetic chromatography

A capillary electrophoresis (CE) method has been developed for simple and direct separation of cis- and trans-12,13-epoxy-9(Z)-octadecenoic acid and 9,10-epoxy-12(Z)-octadecenoic acid isomers. Separation was performed in micellar electrokinetic capillary chromatography (MEKC) using a buffer consisting of 25 mM borate (pH 9.20), 10 mM sodium dodecyl sulfate (SDS) and 10% v/v acetonitrile. The key variables, concentrations of SDS and organic modifier, were optimized by the application of a factorial experimental design. The use of a low micellar concentration, just above critical micelle concentration (CMC), in a background electrolyte containing an organic modifier not only made it possible to dissolve and separate highly hydrophobic fatty acid isomers, but also resulted in improved separation efficiency and selectivity. Separation efficiency up to 4 x 10(5) theoretical plates/m was achieved under an optimized condition. Also investigated were the influence of temperature on separation and the effect of organic modifier concentration on the dynamic exchange of the analytes between micelles and the bulk of the buffer solution. Direct UV was applied for detection of the fatty acids.

The caries-inhibiting effect of a fluoride drop program: a 3-year study on Chinese kindergarten children

OBJECTIVE

To evaluate the caries-inhibiting effect of a fluoride drops program in two kindergartens in Chengdu, Sichuan Province, a fluoride-deficient area.

METHODS

For 3 years, participating children ingested in school 0.25 mg fluoride daily, in the form of drops for 2 to 3-year-olds and 0.5 mg for children age 3 years and older. These systemic fluoride supplements were made available for over 180 days each year and they were distributed by teachers who maintained attendance records. Annual examinations were conducted for 176 2-year-olds who had used the supplements in the kindergartens and 148 control children. After 3 years, 128 test and 112 control children remained in the study.

RESULTS

The results demonstrated a marked reduction in dental caries in the control group: test children had 2.21 decayed, missing, or filled teeth (DMFT)-versus 4.32 in the control group, a reduction rate of 48.84%. The mean DMFT increments over the 3-year period were 1.76 and 3.92, respectively. Over a 1- to 3-year period of supplement use, the group provided with the fluoride drops had consistently lower caries prevalence than the control group. The differences were statistically significant.

CONCLUSIONS

This treatment regimen demonstrated an effective caries-inhibiting effect.

Overexpressed activated retinoid X receptors can mediate growth inhibitory effects of retinoids in human carcinoma cells

Retinoic acid receptors (RARs) and retinoid X receptors (RXRs) mediate the effects of retinoids on gene expression by binding to response elements in retinoid-sensitive genes. RAR- but not RXR-selective retinoids were found in many previous studies to suppress the growth of various cells, implicating RXR-RAR in these effects. Using a co-expression vector for identifying cells that expressed retinoid receptors transiently and 5'-bromo-2'-deoxyuridine incorporation for labeling DNA-synthesizing cells, we found that RXR-selective retinoids inhibited DNA synthesis in squamous carcinoma 1483 cells transfected with RXRalpha but not with RARs. Ligand-induced transcription of the reporter luciferase gene via the activation of RXR-RXR but not RXR-RAR correlated with growth suppression. Studies with RXRalpha deletion mutants indicated that the DNA binding and the ligand binding domains are essential for mediating growth inhibition. A point mutation in the ligand binding domain (L430F) that decreased RXRalpha homodimerization compromised its growth inhibitory function. Further, RXRalpha mutant (F313A), which functions as a constitutively active receptor, inhibited DNA synthesis in the absence of ligand. These results demonstrate that RXR homodimer activation leads to growth inhibition and suggest that transfection of RXRalpha and treatment with RXR-selective retinoids or the transfection of constitutively activated RXRalpha mutant alone may have a therapeutic potential.

Cell lines of pulmonary and non-pulmonary origin as tools to study the effects of house dust mite proteinases on the regulation of epithelial permeability

BACKGROUND

Allergenic and non-allergenic proteinases from house dust mites (HDM) cause loss of adhesion between airway epithelial cells that may result in a loss of functional cohesion between the cells and thus assist in allergen presentation. Improved cellular assay systems are needed to ascertain the mechanisms involved.

OBJECTIVES

To survey a series of epithelial cell lines (Calu-3, 16HBE14o-, NCI-H292 and A549 from human airways, and MDCK from dog kidney) and establish their utility for studies of the effects of HDM proteinases from D. pteronyssinus on epithelial permeability. To develop an improved method for measuring changes in epithelial permeability induced by HDM proteinases and other provocants.

METHODS

The permeability of epithelial monolayer cultures to mannitol was calculated from measurements of clearance using a technique that permits mathematical estimation and reduction of non-cellular diffusional constraints. Permeability was studied under control conditions and after perturbation of monolayers with HDM proteinases (separated into serine- and cysteine-proteinase classes) or chelation of extracellular Ca2+. Fluorescent antibody staining was used to investigate whether the cells expressed tight junctions (staining of ZO-1), desmosomes (staining of desmoplakin) and zonulae adherentes (staining of E-cadherin).

RESULTS

The Calu-3 line was identified as an airway cell line that expressed functional tight junctions, desmosomes and zonulae adherentes. Calu-3 monolayers exhibited a low clearance and permeability to mannitol, similar to that seen in the extensively characterized MDCK cell line. Clearance and permeability were significantly increased by treatment with either HDM proteinase fraction or by calcium chelation. 16HBE14o- cells also had a low permeability to mannitol under control conditions and expressed a similar repertoire of functional proteins from major intercellular junctions. In contrast, NCI-H292 and A549 cell lines were functionally deficient in tight junctions, although they did express desmosomes and zonulae adherentes to a greater extent. Epithelial permeability was found to be a more appropriate and sensitive index of epithelial perturbation than was tracer clearance.

CONCLUSION

These results suggest that the Calu-3 and 16HBE14o- cell lines are useful tools in studying the mechanism of HDM proteinases on airway epithelial cell function. HDM proteinases of both cysteine and serine mechanistic classes were found to perturb epithelial adhesion and function.

Sma I, Hha I, Msp I and Rsa I restriction fragment length polymorphisms in the von Willebrand factor gene of Chinese population

OBJECTIVE

To study Sma I, Hha I, Msp I and Rsa I restriction fragment length polymorphisms in vWF gene of Chinese population.

METHODS

The vWF gene from 52 unrelated individuals of Han Nationality, 44 of Yi tribe, 42 of Dai tribe was analyzed by polymerase chain reaction and digestion of the endonucleases of Sma I, Hha I, Msp I and Rsa I.

RESULTS

The allele frequencies were 0.38:0.62 for Sma I+:Sma I- and 0.38:0.62 for Hha I+:Hha I-; 0.20:0.80 for Msp I+:Msp I-; 0.93:0.07 for Rsa I+:Rsa I- in Chinese Han population. The theoretical heterozygous rates were 0.46, 0.46, 0.36 and 0.13 of these polymorphisms, respectively. The allele frequencies were 0.43:0.57 for Sma I+:Sma I- and 0.43:0.57 for Hha I+:Hha I-, 0.26:0.74 for Msp I+:Msp- in Yi tribe and 0.36:0.64 for Sma I+:Sma I- and Hha I+:Hha I-, 0.17:0.83 for Msp I+:Msp I- in Dai tribe. The theoretical rates were 0.49 for Sma I and Hha I and 0.38 for Msp I in Yi tribe; and 0.45 for Sma I and Hha I, 0.28 for Msp I in Dai tribe, respectively.

CONCLUSIONS

The allele frequencies and theoretical rates of these polymorphisms in vWF gene are different between Chinese populations and Caucasians. They should be useful for the carrier detection and prenatal diagnosis in vWD families of Chinese.

Class specific inhibition of house dust mite proteinases which cleave cell adhesion, induce cell death and which increase the permeability of lung epithelium

1. House dust mite (HDM) allergens with cysteine and serine proteinase activity are risk factors for allergic sensitization and asthma. A simple method to fractionate proteinase activity from HDM faecal pellets into cysteine and serine class activity is described. 2. Both proteinase fractions increased the permeability of epithelial cell monolayers. The effects of the serine proteinase fraction were inhibited by 4-(2-aminoethyl)-benzenesulphonyl fluoride hydrochloride (AEBSF) and soybean trypsin inhibitor (SBTI). The effects of the cysteine proteinase fraction could be inhibited by E-64. No reciprocity of action was found. 3. Treatment of epithelial monolayers with either proteinase fraction caused breakdown of tight junctions (TJs). AEBSF inhibited TJ breakdown caused by the serine proteinase fraction, whereas E-64 inhibited the cysteine proteinase fraction. 4. Agarose gel electrophoresis revealed that the proteinases induced DNA cleavage which was inhibited by the matrix metalloproteinase inhibitor BB-250. Compound E-64 inhibited DNA fragmentation caused by the cysteine proteinase fraction, but was without effect on the serine proteinase fraction. Staining of proteinase-treated cells with annexin V (AV) and propidium iodide (PI) revealed a diversity of cellular responses. Some cells stained only with AV indicating early apoptosis, whilst others were dead and stained with both AV and PI. 5. HDM proteinases exert profound effects on epithelial cells which will promote allergic sensitization; namely disruption of intercellular adhesion, increased paracellular permeability and initiation of cell death. Attenuation of these actions by proteinase inhibitors leads to the conclusion that compounds designed to be selective for the HDM enzymes may represent a novel therapy for asthma.

[Four novel point mutations of factor IX gene detected by denaturing gradient gel electrophoresis]

OBJECTIVE

To identify factor IX gene mutations in patients with hemophilia B.

METHODS

The coding regions, splicing junction sites and part of the 5' and 3' flanking regions of factor IX gene were screened by polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE).

RESULTS

Four amplified fragments showed abnormal electrophoresis patterns, and sequencing of them demonstrated four novel point mutations including a T to G transition at nucleotide 10,380 resulting in intron 3 covering the splicing site, a A to G transition at nucleotide 30,918 resulting in a substitution of Cys for Tyr at codon 266 in exon 8, and a A to C transition at nucleotide 31,007 resulting in a substitution of Pro for Thr at codon 299 in exon 8.

CONCLUSION

Detection of mutations by PCR, DGGE and sequencing was useful not only for understanding the structure function relationship of F IX, but also for the carrier detection and prenatal diagnosis.

[Msp I and Rsa I RFLPs of vWF gene in Chinese Han people]

OBJECTIVE

To study the Msp I and Rsa I restriction fragment length polymorphisms (RFLPs) in the 5' region of human von Willebrand factor gene in Chinese Han people.

METHODS

A 226 bp amplified fragment of human vWF gene from 52 unrelated individuals and a 322 bp amplified fragment from 48 individuals were analyzed by Msp I or Rsa I digestion.

RESULTS

Complete linkage disequilibrium was observed at both Msp I and Rsa I sites in vWF gene in Chinese Han people. The frequencies at the two sites were 0.20/0.80 for Msp I+/Msp I- and 0.93/0.07 for Rsa I+/Rsa I-. The theoretical heterozygous rates were 36% and 10%, respectively.

CONCLUSION

The Msp I and Rsa I RELPs of vWF gene are useful for genetic counseling and prenatal diagnosis of vWD in Chinese Han people.

[Detection of gene mutation and genetic analysis of a patient with type 3 von Willebrand disease]

OBJECTIVE

To identify gene mutations in patients with type 3 von Willebrand disease.

METHODS

The encoding region of von Willebrand factor (vWF) gene were screened by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE).

RESULTS AND CONCLUSION

The fragment of vWF gene exon 3 from a patient with type 3 von Willebrand disease displayed an abnormal melting behavior. Direct sequencing demonstrated a homozygous C-->A transition at nucleotide 212 in vWF gene resulting in the substitution of a stop codon for Ser71. The parents of the patient were heterozygous for this mutation as identified by PCR-DGGE and restriction endonuclease digestion analysis.

[Dermatomyositis and malignancy of the pharynx (report of 3 cases)]

Three patients with dermatomyositis are reported, two of them had suffered from carcinoma of the nasopharynx and the last one suffered tonsillar carcinoma. The diagnosis the therapy, the prognosis and the relationship between dermatomyositis and malignancy were discussed in detail in this paper. The author emphasised that careful examination of the nose and pharynx would be very important for the patient with dermatomyositis.

[Efficacy of a triclosan/copolymer dentifrice in the control of plaque and gingivitis: a six-month study in China]

A total of one hundred fifty three healthy male and female adults were entered into a six month, double-blind clinical study designed to evaluate the effect of a dentifrice containing 0.3% triclosan and 2.0% PVM/MA copolymer in a 0.243% sodium fluoride/silica base, relative to a 0.243% sodium fluoride silica base control dentifrice on supragingival plaque accumulation and gingivitis. Plaque and gingivitis were scored after 3 and 6 months' use of the assigned dentifrice. At the end of the study, the dentifrice containing triclosan/copolymer demonstrated an average reduction, relative to the control dentifrice of 16.1% in plaque accumulation and 24.3% in gingivitis. Both were statistically significant(P < 0.001). It was concluded that the twice-daily use of the triclosan/copolymer containing dentifrice resulted in a significant reduction in plaque formation and a significant improvement in gingival health. No side-effects were observed.

Enhancement of Calu-1 human lung carcinoma cell growth in serum-free medium by retinoids: dependence on AP-1 activation, but not on retinoid response element activation

Many lung cancer cell lines are resistant to the growth inhibitory effects of retinoids. However, some small-cell lung cancer cell lines were inhibited by all trans-retinoic acid (ATRA) in serum-free medium. We compared the responses of seven non-small cell lung cancer (NSCLC) cell lines to ATRA in serum-free medium and in medium supplemented with delipidized serum. Whereas the growth of four cell lines was inhibited more in serum-free medium, the growth of the Calu-1 cell line was stimulated by ATRA in a dose-dependent fashion with a maximum at 10(-8) M. Delipidized serum (>2.5%) but not bovine serum albumin (0.15%) suppressed growth stimulation by ATRA. Transcripts of RA receptors RARalpha and RARgamma but not of RARbeta were detected in Calu-1 cells. Receptor expression, the formation of a complex among receptors and a RA-responsive element (RARE), and the transcriptional activation RARE were not suppressed by serum. Natural retinoids and synthetic receptor class- or subtype-selective retinoid agonists, which activated RARs and RXRs for gene transcription from a RARE, and a RAR antagonist (CD2366), which was unable to do so, stimulated the growth of Calu-1 cells in serum-free medium but not in serum-containing medium. Both ATRA and CD2366 enhanced the transcriptional activation of an Activator Protein-1 (AP-1)-luciferase reporter construct in serum-free medium but not in delipidized serum. Transcriptional activation of the RARE by ATRA occurred both in the presence or absence of delipidized serum. These results demonstrate that retinoid-induced growth stimulation of Calu-1 cells is associated with enhanced AP-1 transactivation but not with RARE transactivation.

[Construction and expression in E. coli of single-chain Fv fragment of antihuman activated platelets monoclonal antibody]

OBJECTIVE

In order to reduce the immunogenicity of murine monoclonal antibody (MAb) to human beings.

METHODS

The cDNA encoding the variable regions of the mouse MAb SZ-51, which is specific against alpha-granule membrane protein(GMP) 140 on activated human platelets, was attached to the oligonucleotide of the linker peptide (Gly4 Ser)3 by means of recombinant DNA technique. The phagemid construct pHEN1-51scFv was obtained and introduced into the non-suppressor E. coli strain HB2151 for expression.

RESULTS AND CONCLUSION

The expressed product could fold up into a soluble single-chain Fv fragment (scFv) and was released into the conditioned medium. The SZ-51scFv was proved to bind specifically to GMP140 by Western blot.

[Construction and expression of a functional chimeric murine-human antibody directing against human cross-linked fibrin]

OBJECTIVE

In order to reduce the immunogenicity of the murine antifibrin monoclonal antibody (MAb) SZ-63 to human beings.

METHODS

First of all, the cDNA sequences encoding the constant regions of the murine kappa light chain and gamma 1 heavy chain in the SZ-63 MAb were substituted with the corresponding human genomic sequences. Then the constructed MAb was cloned separately into two selectable expression vectors, and the latter were transfected into mouse myeloma cells (SP2/0) one by one.

RESULTS

ELISA, Western blot and competition experiment results showed that there was 0.8 approximately 1.0 mg/L of chimeric 63 IgG in the conditioned medium of selected cell lines, and the expressed IgG had higher antifibrin D-Dimer capability than that of the original MAb.

CONCLUSION

The expressed chimeric antibody can be used as a targeting agent for thrombus imaging and treatment.

Chiral separation of DL-peptides and enantioselective interactions between teicoplanin and D-peptides in capillary electrophoresis

Teicoplanin has been evaluated as a selector for enantioseparation of di- and tripeptide derivatives in capillary electrophoresis. Separation variables such as type of buffer, pH, concentrations of teicoplanin and organic modifier were examined. Optimal separation conditions were obtained by means of factorial design experiments. The effects of teicoplanin concentrations below and above its critical micellar concentration (CMC) and of acetonitrile (ACN) on the separation were demonstrated. The use of a high concentration of ACN resulted not only in increased selectivity, but also in improved separation efficiency. Electroosmotic flow was observed to be largely independent of the concentrations of teicoplanin under the optimized conditions. Good repeatability of migration times was obtained. The interactions between teicoplanin and D and L peptides were studied, and it was found that, for some peptides, teicoplanin exhibited enantioselective interaction only with the D-form. Somewhat lower separation efficiencies were thus observed for the strongest interacting (D-form) peptides. Chiral separation of 15 DL-peptide derivatives was achieved in less than 10 min.

Construction and expression of mouse-human chimeric antibody SZ-51 specific for activated platelet P-selectin

A murine monoclonal (mAb) SZ-51 specific for human P-selectin may be used for in vivo thrombus imaging and for the targeting of fibrinolytic agents to thrombi. In order to reduce the immunogenicity of the murine mAb SZ-51 in humans, we cloned and sequenced the cDNAs encoding the variable region of mAb SZ-51 in order to develop mouse/human chimeric reagents. The E. coli expression vector pHEN1-SZ51Fab/Hu was constructed by fusing the variable regions of mAb SZ-51 with human IgG gamma 1CH1 and C kappa genes. The constructs were introduced into E. coli HB2151 for expression of soluble chimeric Fab fragment. We also constructed two fusion products by joining the variable regions of mouse antibody to the appropriate constant regions of human Ig gamma 1 and kappa. These chimeras were cloned into two eukaryotic selectable expression vectors separately, which were then contransfected into a non-Ig secreting murine myeloma line SP2/0 with lipofectin reagent. Six cell lines remained positive for Ig secretion. The highest producing cell line, which showed stable integration and expression at 5 mg/l of culture, was selected for the large scale production of chimeric antibody. Immunoblotting analysis demonstrated that both of the chimeric antibodies (SZ51Fab/Hu, SZ51/Hu) in the culture supernatants, like the native mAb SZ-51, bind P-selectin. In addition, the whole chimeric antibody can compete for binding to activated platelets with murine SZ-51. Therefore, the SZ-51 chimeric antibody may be a potential agent for diagnosis and treatment of thrombotic diseases in the future.

A study of cell behaviour on the surfaces of multifilament materials

Since many fibres are very strong, they are considered to have useful potential for fibre reinforcement of orthopaedic and dental implant materials. Fibres exposed on the surface of composites may significantly influence the cellular response not only due to the chemistry but also due to the fibre size and shape. This study has concentrated on investigation of cellular responses to fibre-specific aspects of fibre-reinforced composites. Four multifilament materials with diameter less than 20 microm were used: Kevlar 29(K), silicon carbide(SiC), nylon 66(N), and polyethylene terephthalate(PET). Established cell line L929 fibroblasts were used as the cell model. Cell behaviour on the surfaces of fibres was examined using direct cell counting (after 3, 5, 8 h and 1, 2, 3 days), scanning electron microscopy (SEM) (after 2 h and 2 days), and fluorescent staining of F-actin, which was analysed by confocal laser scanning microscopy (CLSM) (after 2 h and 2 days). The results showed that fibroblasts adhered and grew very well on all fibre surfaces, although less cells were observed on PET from direct cell counting. Significant orientational behaviour of cells was found on all fibre surfaces from the SEM and CLSM analysis, independent of the bulk chemistry of the fibres.

Enantioseparation of amino acids and dipeptides using vancomycin as chiral selector in capillary electrophoresis

Vancomycin was applied as chiral selector for the enantiomeric separation of derivatized amino acids and dipeptides. The influence of vancomycin concentration, pH and presence of 2-propanol in the buffer were examined in order to find optimal separation conditions. Optimization was by factorial design. Further, chiral separation of derivatives prepared with three different reagents was compared. These reagents were 9-fluorenylmethyl chloroformate (FMOC), 2-(9-anthryl)ethyl chloroformate (AEOC) and dansyl chloride (dansyl). Optimum resolution was at high vancomycin concentrations, while optimum efficiency was at low vancomycin concentrations. As a consequence of the very high enantioselectivity of vancomycin, the vancomycin concentration below the amount necessary for maximal resolution can be used. Separation efficiency was relatively low, and this could be attributed to adsorption of the selector at the capillary wall. Three factors led to decreased adsorption: application of a pH above the zero mobility pH value, low vancomycin concentrations and the presence of 2-propanol. For amino acids, the resolutions of the different derivatives were: dansyl > AEOC > FMOC, while for dipeptides, the highest selectivity was with AEOC.

Recognition of diverse sequences by class I zinc fingers: asymmetries and indirect effects on specificity in the interaction between CF2II and A+T-rich elements

The Drosophila CF2II protein, which contains zinc fingers of the Cys2His2 type and recognizes an A+T-rich sequence, behaves in cell culture as an activator of a reporter chloramphenicol acetyltransferase gene. This activity depends on C-terminal but not N-terminal zinc fingers, as does in vitro DNA binding. By site-specific mutagenesis and binding site selection, we define the critical amino acid-base interactions. Mutations of single amino acid residues at the leading edge of the recognition helix are rarely neutral: many result in a slight change in affinity for the ideal DNA target site; some cause major loss of affinity; and others change specificity for as many as two bases in the target site. Compared to zinc fingers that recognize G+C-rich DNA, CF2II fingers appear to bind to A+T-rich DNA in a generally similar manner, but with additional flexibility and amino acid-base interactions. The results illustrate how zinc fingers may be evolving to recognize an unusually diverse set of DNA sequences.

Preparation of an antifibrin thrombus-specific murine/human chimeric monoclonal antibody Fab fragment in Escherichia coli

We have successfully developed a murine antifibrin monoclonal antibody designated SZ-63 with property of binding specifically with thrombus both in vitro and in vivo. In order to reduce its immunogenicity and molecular weight, a murine/human chimeric Fab fragment of the antibody was prepared. mRNA was selected on oligo (dT) cellulose from total RNA isolated from SZ-63 hybridoma cells. cDNAs coding for heavy and light variable regions were amplified by reverse transcriptase polymerase chain reaction. The amplified fragments were cloned and sequenced. The nucleotides of SZ-63 VH and VL are 354 and 321 respectively. The variable genes were then linked with human IgG gamma1 CH and kappa CL genes. Expression vector pHEN1-63 Fab/Hu was thereby constructed and chimeric Fab fragment was expressed in E. coli HB2151 cells in soluble form. Western blot and ELISA results showed that it remained the same capability of binding with cross-linked fibrin as the murine SZ-63 antibody, the content in culture is about 125 ug/L.

The effects of L-AP4 and L-serine-O-phosphate on inhibition in primary somatosensory cortex of the adult rat in vivo

The effects of two iontophoretically applied Group III mGluR agonists were studied on the inhibition in neocortex produced by natural stimulation of vibrissae. The agonists L-AP4 and L-serine-O-phosphate (L-SOP) were shown to produce qualitatively similar effects on the inhibition. Forty-four percent of neurones (total n = 57) displayed disinhibition during application of the agonists. The disinhibitory effects often outlasted the offset of the agonist application by at least 10 min. Concurrent application of the mGluR antagonist (+)-alpha-methyl-4-carboxyphenylglycine ((+)-MCPG) appeared to reverse the disinhibitory effects of L-AP4 and L-SOP in 3 out of 5 neurones tested. However (+)-MCPG itself was found to have disinhibitory effects in some neurones. Some neurones (n = 7) showed increases in inhibition during either L-AP4 or L-SOP application. These appeared most pronounced in those neurones where the initial (pre-drug) inhibition was minimal, perhaps suggesting that the agonists were disinhibiting a local disinhibition. The data obtained in the experiments suggest that the disinhibitory effects are mediated by a heteroreceptor on inhibitory terminals, action at which depresses the release of inhibitory transmitter. The possible role of the modulation of inhibition by presynaptic mGluRs is discussed.

In vitro and in vivo characterization of BR96 sFv-PE40. A single-chain immunotoxin fusion protein that cures human breast carcinoma xenografts in athymic mice and rats

BR96 sFv-PE40 is a single-chain immunotoxin fusion protein targeted to the Ley Ag, which is expressed in many different human carcinomas as well as in normal gastrointestinal epithelium of humans and certain animals, including athymic rats but not mice. In vitro binding analysis determined that BR96 sFv-PE40 was similar in affinity to BR96 Fab. BR96 sFv-PE40 internalizes rapidly, similar to BR96 IgG. H3396 cells, derived from metastatic human breast carcinoma, have been established as tumor xenografts in estradiol-supplemented athymic mice and rats. H3396 tumor xenografts established in athymic mice (up to 350 mm3) and rats (up to 100 mm3) completely regressed after i.v. administration of BR96 sFv-PE40, given as 0.625 mg/kg (1.975 mg/m2) every 4th day for a total of five doses (mice) or 0.25 mg/kg (1.475 mg/m2) every 4th day for a total of four doses (rats). The tumors remained regressed for the duration of the study (> 85 days post-implant), which represents > 10 doubling times, indicating that the animals were cured. There was no toxicity in rats receiving a curative dose of 0.25 mg/kg, although liver and lung toxicity could be detected at a 16 times higher dose, 4 mg/kg or 23.6 mg/m2. We conclude, therefore, that BR96 sFv-PE40 can cure tumor xenografts at well tolerated doses and also in the presence of Ley expression in normal tissues.

In vitro and in vivo characterization of BR96 sFv-PE40. A single-chain immunotoxin fusion protein that cures human breast carcinoma xenografts in athymic mice and rats

BR96 sFv-PE40 is a single-chain immunotoxin fusion protein targeted to the Ley Ag, which is expressed in many different human carcinomas as well as in normal gastrointestinal epithelium of humans and certain animals, including athymic rats but not mice. In vitro binding analysis determined that BR96 sFv-PE40 was similar in affinity to BR96 Fab. BR96 sFv-PE40 internalizes rapidly, similar to BR96 IgG. H3396 cells, derived from metastatic human breast carcinoma, have been established as tumor xenografts in estradiol-supplemented athymic mice and rats. H3396 tumor xenografts established in athymic mice (up to 350 mm3) and rats (up to 100 mm3) completely regressed after i.v. administration of BR96 sFv-PE40, given as 0.625 mg/kg (1.975 mg/m2) every 4th day for a total of five doses (mice) or 0.25 mg/kg (1.475 mg/m2) every 4th day for a total of four doses (rats). The tumors remained regressed for the duration of the study (&gt; 85 days post-implant), which represents &gt; 10 doubling times, indicating that the animals were cured. There was no toxicity in rats receiving a curative dose of 0.25 mg/kg, although liver and lung toxicity could be detected at a 16 times higher dose, 4 mg/kg or 23.6 mg/m2. We conclude, therefore, that BR96 sFv-PE40 can cure tumor xenografts at well tolerated doses and also in the presence of Ley expression in normal tissues.

Two-dimensional gas chromatography for the enantiomeric separation of ephedrine and phenaminum and their metabolites

Two-dimensional gas chromatography was used for enantiomeric separation of ephedrine, phenaminum and their metabolites in human urine. The main column was coated with a 2,6-di-O-pentyl-3-O-trifluoroacetylated-alpha-cyclodextrin and an SE-54 phase column was used as precolumn. The results showed that two-dimensional chromatography could greatly simplify the sample preparation, eliminate the interference of sample matrices, and improve the resolution of the enantiomers of interest.