[The present research situation of cause of formation of impedance cardiograph waveform]

This paper summarized the present research situation of cause of formation of impedance cardiograph waveform in two aspects of early and current research on it by the means of consulting a great deal of domestic and foreign data. The paper pointed out that a practicable way for correcting Kubicek theory and its physical model, making SV formula more accurate is to apply finite element technology to the research field under the guide of impedance cardiograph electric field theory. At the same time, the paper made preliminary introduction on the author's research work in the area.

A model for Ku heterodimer assembly and interaction with DNA. Implications for the function of Ku antigen

Ku autoantigen, a heterodimer of 70- and 80-kDa subunits, is a DNA end-binding factor critical for DNA repair. Two domains of p70 mediate DNA binding, one on the C-terminal and one on the N-terminal portion. The latter must dimerize with p80 in order to bind DNA, whereas the former is p80-independent. Both must be intact for end binding activity in gel shift assays. To evaluate the role of p80 in DNA binding, deletion mutants were co-expressed with full-length p70 using recombinant baculoviruses. We show by several criteria that amino acids 371-510 of p80 interact with p70. Both of the p70 dimerization domains bind to the same region of p80, but apparently to separate sites within that region. In DNA immunoprecipitation assays, amino acids 179-510 of p80 were required for p80-dependent DNA binding of p70, whereas in gel shift assays, amino acids 179-732 were necessary. Interestingly, both the p80-dependent and the p80-independent DNA binding sites preferentially bound to DNA ends, suggesting a model in which a single Ku heterodimer may juxtapose two broken DNA ends physically, facilitating their rejoining by DNA ligases.

Fusion of macrophages on an implant surface is associated with down-regulated expression of ligands for galectin-1 and -3 in the rat

Galectins have a wide range of biological activities which are elicited by binding to appropriate glycoligands. Besides regulation of the expression of the galectins the extent of the presence of suitable binding sites will be relevant to infer the cellular responsiveness to this class of sugar receptors. Thus ligand presentation requires monitoring by the tissue lectin. We demonstrate the expression of galectin-3 by macrophages and foreign-body giant multinucleate cells colonizing a cellophane implant in the rat by the A1D6 monoclonal antibody. The extents of ligand presence are visualized in the same cells by biotinylated galectin-3 and also by galectin-1 which is produced by diverse mammalian cell types and widely distributed. Labeled mistletoe (VAA) and tomato (LEA) lectins are used as tools to assess the degree of similarity of the binding profile between endogenous and exogenous proteins. The presentation of alpha-galactosides is monitored with a natural immunoglobulin G subfraction obtained by two consecutive affinity chromatography steps. The binding of labeled galectins and plant lectins was significantly lower to foreign-body giant multinucleate cells than to mononuclear macrophages. The application of the alpha-galactoside-specific probe yielded no significant staining. The potential problem of epitope accessibility could be excluded by the concomitant positivity obtained with an IgG subfraction with selectivity to beta-galactosides also obtained by affinity chromatography. These results provide no evidence for a role of alpha-galactosides for the binding of galectins in the rat macrophages colonizing the implant. The reduced level of expression of glycoligands for galectin-1 and -3 in foreign-body giant multinucleate cells in contrast with the mononuclear macrophages suggests an inhibitory influence of macrophage fusion on the expression of galectin-reactive molecules.

Prodrugs of anthracyclines for use in antibody-directed enzyme prodrug therapy

A series of new prodrugs of daunorubicin and doxorubicin which are candidates for antibody-directed enzyme prodrug therapy (ADEPT) is reported. These compounds (25a,b,c and 32a,b,c) have been designed to generate cytotoxic drugs after activation with beta-glucuronidase. As expected, recovery of the active drug was observed after enzymatic cleavage by Escherichia coli beta-glucuronidase as well as by a fusion protein which has been obtained from human beta-glucuronidase and humanized CEA-specific binding region. The six prodrugs are highly stable and are more than 100-fold less cytotoxic than doxorubicin against murine L1210 cell lines. The ortho-substituted phenyl carbamates 25a,b,c are better substrates for beta-glucuronidase than the corresponding para-substituted analogues. After taking into account additional factors such as stability in plasma and kinetics of enzymatic cleavage, we selected the o-nitro prodrug 25c for clinical trials.

Polyglutamine-expanded human huntingtin transgenes induce degeneration of Drosophila photoreceptor neurons

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder. Disease alleles contain a trinucleotide repeat expansion of variable length, which encodes polyglutamine tracts near the amino terminus of the HD protein, huntingtin. Polyglutamine-expanded huntingtin, but not normal huntingtin, forms nuclear inclusions. We describe a Drosophila model for HD. Amino-terminal fragments of human huntingtin containing tracts of 2, 75, and 120 glutamine residues were expressed in photoreceptor neurons in the compound eye. As in human neurons, polyglutamine-expanded huntingtin induced neuronal degeneration. The age of onset and severity of neuronal degeneration correlated with repeat length, and nuclear localization of huntingtin presaged neuronal degeneration. In contrast to other cell death paradigms in Drosophila, coexpression of the viral antiapoptotic protein, P35, did not rescue the cell death phenotype induced by polyglutamine-expanded huntingtin.

[YY1 and its repressive effect on human papillomavirus 16 early promoter P97 existed widely among human epithelial cell lines]

Cellular transcription factor YY1 represses the activity of early promoter P97 of HPV 16. Removal of the specific binding sites for YY1 in HPV 16 LCR can increase the P97 activity. To analyse the expression of YY1 and the existence of the activation effect on P97 due to removing YY1 binding sites in the LCR region, we extracted nuclear proteins from four cervical cancer cell lines and two human keratinocytes. EMSA assays were carried out in vitro. At the same time, we transiently transfected the luciferase reporter plasmids, which contain HPV 16 reference and mutated LCR sequences, respectively, into the different cells and determined the luciferase expressions. The results showed that all the analysed cell lines contained biologically functional YY1 proteins. No remarkable difference in the concentration of native YY1 proteins could be detected among the tested cells. Removal of YY1 binding sites in HPV 16 LCR could elevate P97 activity in several analysed cell lines, including normal human primary kerationcytes from foreskin. It suggests that YY1 regulatory system exists widely in human epithelial cell lines. We also found that the transcription activator NF1 was more highly expressed in C33a cell than in HT3 cell, indicating an unevenly distribution of functional proteins in various cell lines.

[The choice of intraocular lens before cataract extraction for cases with high myopia]

OBJECTIVE

To study the choice of diopter and size of optical portion of intraocular lens (IOL) before cataract extraction for cases with high myopia.

METHODS

Extracapsular cataract extraction (ECCE) or phacoemulsification with IOL implantation was performed on 60 cases (94 eyes) with high myopia (axial length > 26mm). The posterior chamber IOL selected and inserted was the one with the diopter and size of the optical portion suitable for the recipient to have a postoperative low myopia and easy to be examined with an ophthalmoscope.

RESULTS

The postoperative eyes were of low myopia, -2.07 +/- 1.95 D. The larger size of optical portion was more suitable for ocular fundus examination. Great care was taken for phacoemulsification for cataractous nucleus below III grade.

CONCLUSIONS

For patients with axial myopia, the IOL implanted should create low myopia postoperatively. Larger optic size is better for fundus examination. Phacoemulsification can produce less astigmatism and damage, but the indication must be controlled strictly.

Autoantibodies to DEK oncoprotein in a patient with systemic lupus erythematosus and sarcoidosis

A patient was identified with an unusual autoimmune syndrome consisting of systemic lupus erythematosus and sarcoidosis. Her serum contained extremely high levels of autoantibodies to the DEK protooncogene product. The patient's serum was used to clone a dek complementary DNA, which was expressed as a histidine-tagged fusion protein in Escherichia coli. Using affinity-purified recombinant DEK protein, anti-DEK autoantibodies were found in the patient's serum at a titer of 1:10(6) by enzyme-linked immunosorbent assay (ELISA). Longitudinal studies revealed marked variations in anti-DEK autoantibody levels over time. Although it has been suggested that anti-DEK autoantibodies are a marker for pauciarticular juvenile rheumatoid arthritis with iridocyclitis, the present data suggest that they may be associated with other disease subsets as well. The quantitative ELISA technique will be useful for defining these subsets further and for examining the relationship between anti-DEK titers and disease activity.

SA, JA, ethylene, and disease resistance in plants

Exciting advances have been made during the past year: isolating mutants affecting plant disease resistance, cloning genes involved in the regulation of various defense responses, and characterizing novel defense signaling pathways. Recent studies have demonstrated that jasmonic acid and ethylene are important for the induction of nonspecific disease resistance through signaling pathways that are distinct from the classical systemic acquired resistance response pathway regulated by salicylic acid.

[Treatment of intraocular fibrinous membrane by anterior chamber injection of tissue plasminogen activator after IOL implantation]

OBJECTIVE

To investigate the method of treatment of intraocular fibrinous membrane by tissue plasminogen activator (t-PA) after intraocular lens (IOL) implantation and evaluate its clinical results.

METHODS

58 eyes of 43 patients after cataract surgery were divided into three groups, and received t-PA anterior chamber (AC) injection or combined with YAG laser therapy at different times after the operation. Group 1 included 26 eyes which received 4 microg t-PA AC injection at the end of operation. In group 2, 22 eyes whose fibrinous membrane was formed 5 - 7 days after the operation were injected with 4 microg t-PA at that time. In group 3, 10 eyes with thicker membrane were given YAG laser treatment at postoperative 5 - 9 days and then 4 microg t-PA was injected into the AC.

RESULTS

In group 1, hyphema occurred in 4 eyes, in 8 eyes at the pupillary region the fibrinous membrane was formed which was completely lysed after t-PA AC injection at postoperative 3 - 5 days. In group 2, the membrane was lysed within 24 hours in 20 of 22 eyes and no hyphema was found. In group 3, the membrane was lysed within 4 - 24 hours after t-PA injection in all cases, and no hyphema occurred.

CONCLUSION

It is very effective to treat fibrinous membrane formation after IOL implantation by t-PA AC injection at postoperative 1 week when the AC inflammation is well controlled. The combined use of YAG laser with t-PA AC injection is much more effective for the treatment of such a membrane.

[Implementing a relatively rigorous algorithm of dynamic EIT problem on the modified FEM model]

We deduced a relatively rigorous algorithm of dynamic EIT problem-general inverse algorithm, and implemented it on the computer FEM model. Images which can show the changing of the resistivity(i.e. dynamic resistivity images) were gained. Also we modified the ordinary FEM model according to the characteristic of the EIT problem and implemented the general inverse algorithm on the modified model. The ill-posed condition of the forward matrix based on the modified model was fairly improved. It can be seen from the results that the general inverse algorithm with modified FEM model is an algorithm better than the back-projection algorithm in terms of object locating, image definition, and the ability of dealing with complex object and noise.

Generation of broad-spectrum disease resistance by overexpression of an essential regulatory gene in systemic acquired resistance

The recently cloned NPR1 gene of Arabidopsis thaliana is a key regulator of acquired resistance responses. Upon induction, NPR1 expression is elevated and the NPR1 protein is activated, in turn inducing expression of a battery of downstream pathogenesis-related genes. In this study, we found that NPR1 confers resistance to the pathogens Pseudomonas syringae and Peronospora parasitica in a dosage-dependent fashion. Overexpression of NPR1 leads to enhanced resistance with no obvious detrimental effect on the plants. Thus, for the first time, a single gene is shown to be a workable target for genetic engineering of nonspecific resistance in plants.

Glycohistochemical properties of malignancies of lung and pleura

Based upon the reasoning that protein-carbohydrate recognition is involved in diverse intercellular activities including growth control and cell motility 14 probes have been employed to characterize epitope presence in sections of 80 cases with operated lung carcinomas, 20 patients with mesothelioma, and 20 cases with non-malignant lung diseases. As parts of the innate immune system with supposed relevance for host defense the mannan-binding lectin (MBL) and serum amyloid P component (SAP) were employed. The naturally occurring immunoglobulin G fractions with selectivity for alphaa-galactosides (alpha+) and beta-galactosides (beta+) and their subfractions with enhanced target selectivity (alpha+beta-,alpha-beta+) allowed the monitoring of expression of reactive sites for these autoantibodies as a step to elucidate potential anti-tumor activity. Due to the diversity of cellular galactoside-containing glycoconjugates two galectins and a plant lectin were included. As a measure of receptor activities for carbohydrates, neoglycoconjugates with alpha-galactose, the B-disaccharide, the Forssman-disaccharide, and alpha-glucose as histochemically crucial ligand part were tested in addition to an antibody against heparin-binding lectin. Quantitative image analysis revealed significant differences between cases with small cell and non-small cell lung cancer for the plant lectin and one galectin, cases with non-tumorous lung disease and lung carcinoma for serum amyloid P component and the beta-galactoside-selective autoantibody fraction. Prognostic relevance was observed for the presence of glucose-specific sites in small cell lung cancer and meso-thelioma cases, and of galectin- and alpha-galactoside-selective immunoglobulin G fraction-binding sites in non-small cell lung cancer patients.

[The studies on MTS1/p16 gene deletion during transformation of human bronchial epithelial cells]

OBJECTIVE

To detect the deletion of MTS1/p16 and the expression of P16 protein during the transformation of human bronchial epithelial cell line M.

METHODS

Dual-color fluo-rescence in situ hybridization (FISH), immunohistochemical staining and western blot analysis were carried out.

RESULTS

No deletion of MTS1/p16 gene was found in MP18 cells of the cell line M. But partial deletions occurred in the MP36 and MP120 cells of the cell line M. Immunohistochemical analysis and western blot test showed lower expression of P16 protein in the MP120 cells than in MP20 cells.

CONCLUSIONS

MTS1/p16 gene deletion contributes to the malignant transformation of the human bronchial epithelial cell line M. Also FISH is a useful technique in detecting gene deletion.

Uncoupling PR gene expression from NPR1 and bacterial resistance: characterization of the dominant Arabidopsis cpr6-1 mutant

In Arabidopsis, NPR1 mediates the salicylic acid (SA)-induced expression of pathogenesis-related (PR) genes and systemic acquired resistance (SAR). Here, we report the identification of another component, CPR 6, that may function with NPR1 in regulating PR gene expression. The dominant CPR 6-1 mutant expresses the SA/NPR1-regulated PR genes (PR-1, BGL 2, and PR-5) and displays enhanced resistance to Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2 in the absence of SAR induction. cpr 6-1-induced PR gene expression is not suppressed in the cpr 6-1 npr1-1 double mutant but is suppressed when SA is removed by salicylate hydroxylase. Thus, constitutive PR gene expression in cpr 6-1 requires SA but not NPR1. In addition, resistance to P. s. maculicola ES4326 is suppressed in the cpr 6-1 npr1-1 double mutant, despite expression of PR-1, BGL 2, and PR-5. Resistance to P. s. maculicola ES4326 must therefore be accomplished through unidentified antibacterial gene products that are regulated through NPR1. These results show that CPR 6 is an important regulator of multiple signal transduction pathways involved in plant defense.

Characterization of polysiloxanes with different functional groups by time-of-flight secondary ion mass spectrometry

Polydimethylsiloxane (PDMS), polyhydromethylsiloxane (PHMS), and polymethylphenylsiloxane (PMPhS) have been studied by TOF-SIMS to investigate effects of functional group changes on polymer fragmentation mechanisms. Cyclic fragments are observed in the low mass range spectra of PDMS and PHMS, but not in the spectrum of PMPhS. Effects of functional group substitution on the fragmentation mechanisms of polysiloxanes are evident in the high mass range spectra (>1000 Da). Peaks of oligomers cationized by silver dominate the high mass range of the spectra of all low molecular weight polysiloxanes. However, fragmentation patterns of these samples are different. Neutral cyclic fragments cationized by silver are identified in the high mass range of the spectra of PDMS and PHMS, but not in the spectrum of PMPhS. The major fragments of PHMS and PMPhS are [oligomer-14+Ag](+). The PHMS spectrum also shows peaks [oligomer-28+Ag](+). These distinctive fragmentation patterns can be used to identify the polysiloxanes.

[Congenital cataract extraction with intraocular lens implantation in children]

OBJECTIVE

To evaluate the results of cataract extraction with intraocular lens (IOL) implantation in children.

METHODS

Cataract extracapsular extraction with anterior vitrectomy and IOL implantation was performed on 104 eyes of 64 children with congenital cataract aged 1.5 - 14 years old. The visual acuity and possible complications were followed up for a mean period of 22 months.

RESULTS

After operation 86.4% patients were relieved from blindness, 62.7% obtained corrected vision >or= 0.3, binocular vision and stereopsis were restored in 41.8% and 30.6% respectively. In 3 eyes secondary cataract developed and in 5 eyes slight iris capture occurred.

CONCLUSIONS

Cataract extraction with anterior vitrectomy and IOL implantation is effective in pediatric cataract treatment. Most patients get remarkable improvement in visual acuity and visual function with minimal complications after surgery. The influence factors on the postoperative visual function need further study.

Identification of two domains of the p70 Ku protein mediating dimerization with p80 and DNA binding

The Ku autoantigen is a heterodimer of 70 (p70) and approximately 80 kDa (p80) subunits that is the DNA-binding component of the DNA-dependent protein kinase (DNA-PK) complex involved in DNA repair and V(D)J recombination. Binding to DNA ends is critical to the function of DNA-PK, but how Ku interacts with DNA is not completely understood. To define the role of p70 and p80 and their dimerization in DNA binding, heterodimers were assembled by co-expressing the subunits using recombinant baculoviruses. Two p70 dimerization sites, amino acids 1-115 and 430-482, respectively, were identified. Binding of p70 to linear double-stranded DNA could be demonstrated by an immunoprecipitation assay, and required the C-terminal portion (amino acids 430-609), but not interaction with p80. The p70 mutants 1-600, 1-542, 1-115, and 430-600 did not bind DNA efficiently. However, DNA binding of 1-600, 1-542, and 1-115, but not 430-600, was restored by dimerization with p80, indicating that p70 has two DNA binding sites, each partially overlapping one of the dimerization sites. The C-terminal domain can bind DNA by itself, but the N-terminal domain requires dimerization with p80. These observations could be relevant to the multiple functional activities of Ku and explain controversies regarding the role of dimerization in DNA binding.

[A preliminary observation on nuclear changes of human corneal endothelial cells in different kinds of corneal diseases]

OBJECTIVE

To investigate the influence of different kinds of corneal diseases on corneal endothelial cells.

METHODS

The endothelial cells of 91 corneal buttons obtained at the time of penetrating keratoplasty (PKP) were stained by 1% alizarin red and 0.25% trypan blue and observed under biomicroscope.

RESULTS

Binuclear and polynuclear endothelial cells were found in every buttons.

CONCLUSION

Under special conditions, the human corneal endothelial cells possibly have stronger ability of mitosis and compensation.

[Effects of electrical stimulation of SII and electroacupuncture on beta-endorphin contents in the perfusate from the nucleus centrum medianum of the thalamus in cats]

In order to probe into whether beta-endorphin is involved in descending modulation of the somatosensory area (SII) of the cerebral cortex on the nucleus centrum medianum (CM) of the thalamus and this mechanism of acupuncture analgesia, it was investigated that effects of electrical stimulation of SII and electroacupuncture on beta-endorphin content in the perfusate from the nucleus CM. Adult cats were randomly divided into three groups: control, electroacupuncture and electrical stimulation of SII. Push-pull perfusion technique was used to collect the perfusate from the nucleus CM beta-endorphin contents in the perfusate were determined with radioimmunoassay. The results indicated that beta-endorphin content in the perfusate was increased significantly by electrical stimulation of SII and not by electroacupuncture, suggesting that the beta-endorphin release from the nucleus CM was elevated by the stimulation of SII and was not influenced by electroacupuncture. It is indicated that beta-endorphin is possibly involved in the descending regulatory effect of electrical stimulation of SII on the nucleus CM, but is not involved in the regulatory effect of electroacupuncture on the nucleus CM.

Neoglycoproteins with the synthetic complex biantennary nonasaccharide or its alpha 2,3/alpha 2,6-sialylated derivatives: their preparation, assessment of their ligand properties for purified lectins, for tumor cells in vitro, and in tissue sections, and their biodistribution in tumor-bearing mice

Neoglycoproteins were prepared with chemoenzymatically synthesized complex biantennary N-glycan derivatives the nonreducing ends of which bear typical sequences found in glycoproteins. A chemically obtained biantennary heptasaccharide-azide was reduced and acylated with a 6-aminohexanoyl spacer. Elongation of the deprotected heptasaccharide using glycosyltransferases yielded a biantennary nonasaccharide with terminal galactose residues and two undecasaccharides terminating with alpha 2,6- or alpha 2,3-linked sialic acid. The free amino group of the spacer of these oligosaccharides was converted into an isothiocyanate. Its subsequent coupling to bovine serum albumin gave neoglycoproteins with a yield of 2.4-3.6 glycan chains per carrier molecule. This versatile synthetic pathway allows employment of a wide variety of complex-type glycans, which can be introduced to various test systems in vitro and in vivo to evaluate potential biomedical applications. Solid-phase assays with biotinylated sugar receptors revealed discriminatory binding properties of the three neoglycoproteins, especially for the mistletoe lectin. This direct assay system is preferable to the measurement of inhibitory capacities with respect to model ligands. Ligand type- and cell type-dependent quantitative differences in the binding properties of the probes were detected by FACScan analyses with a panel of tumor cell lines and by monitoring of staining in tissue sections for small cell and non-small-cell lung cancer and mesotheliomas. Biodistribution of iodinated neoglycoproteins in mice gave a prolonged presence of the sialylated probes in serum. Relative to the nonasaccharide, the uptake, especially of the iodinated neoglycoprotein with alpha 2,3-sialylated ligand chains, was clearly elevated in mice for kidneys and Ehrlich tumors. On the basis of the documented feasibility of these applications, it is concluded that the further elaboration of glycan chain variants by the described synthetic approach in combination with the given test panel is warranted to evaluate the potential of complex glycan chain-carrying neoglycoproteins for diagnostic and therapeutic purposes.

[A digital filter method for the elimination of 50 Hz interference from the ECG]

The author uses improved Levkov method to remove 50 Hz interference from ECG signal so that filtered QRS wave can be exactly regarded as the mark identifying other physiological signals' characteristics points, and the paper presented the result of the cancelling.

The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance

The cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (SAR). This single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. The cpr5 plants were found to be constitutively resistant to two virulent pathogens, Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2; to have endogenous expression of the pathogenesis-related gene 1 (PR-1); and to have an elevated level of salicylic acid (SA). Lines homozygous for cpr5 and either the SA-degrading bacterial gene nahG or the SA-insensitive mutation npr1 do not express PR-1 or exhibit resistance to P. s. maculicola ES4326. Therefore, we conclude that cpr5 acts upstream of SA in inducing SAR. However, the cpr5 npr1 plants retained heightened resistance to P. parasitica Noco2 and elevated expression of the defensin gene PDF1.2, implying that NPR1-independent resistance signaling also occurs. We conclude that the cpr5 mutation leads to constitutive expression of both an NPR1-dependent and an NPR1-independent SAR pathway. Identification of this mutation indicates that these pathways are connected in early signal transduction steps and that they have overlapping functions in providing resistance.

The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance

The cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (SAR). This single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. The cpr5 plants were found to be constitutively resistant to two virulent pathogens, Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2; to have endogenous expression of the pathogenesis-related gene 1 (PR-1); and to have an elevated level of salicylic acid (SA). Lines homozygous for cpr5 and either the SA-degrading bacterial gene nahG or the SA-insensitive mutation npr1 do not express PR-1 or exhibit resistance to P. s. maculicola ES4326. Therefore, we conclude that cpr5 acts upstream of SA in inducing SAR. However, the cpr5 npr1 plants retained heightened resistance to P. parasitica Noco2 and elevated expression of the defensin gene PDF1.2, implying that NPR1-independent resistance signaling also occurs. We conclude that the cpr5 mutation leads to constitutive expression of both an NPR1-dependent and an NPR1-independent SAR pathway. Identification of this mutation indicates that these pathways are connected in early signal transduction steps and that they have overlapping functions in providing resistance.

Glycine68 to histidine73 has an important role in the function of human tumor necrosis factor alpha

Mutant human tumor necrosis factor alpha(hTNF alpha) genes have been constructed by in vitro mutagenesis and expressed in Escherichia coli. A deletion involving Gly68 to His73 in hTNF alpha remarkably decreased the solubility and biological activity of hTNF alpha. From the above and results of a molecular dynamics simulation it is proposed that the region of Gly68 to His73 in hTNF alpha has an important role in the maintenance of the 3-D structure and modulation of the biological activity of hTNF alpha.

[Experimental study of distribution of stress and strain on pelvis in normal Chinese adult]

To approach the biomechanical properties of pelvis in normal Chinese adult, an intact pelvis taken from fresh healthy male cadaver after sudden death was used in this study. The pelvis joined up with lumber4, 5 and proximal segment of femurs. After appropriate management of the specimen, the loads in the simulated test (stand position of normal adult) are 300 N, 600 N and 900 N. With strain electric measuring apparatus, the distribution of stress and strain, and the actual linear strain of every measuring point are obtained. Data processing was performed on computer. The main stress sigma 1, sigma 2 and their direction angles were acquired. The results of the simulated test demonstrated that the stress of iliac bone adjacent to sacro-iliac articulation was maximum in all measuring points. The linear strain values of 0 degree direction parallel with coronal section were negative in majority, but those of 45 degrees and 90 degrees direction vertical with coronal section were positive in majority. So the distribution of the linear strain of pelvis should be very complicated. When 900 N weight acted on the pelvis, the maximum main stress sigma max = 0.269-20.01 MPa and the minimum main stress sigma min = -0.095(-)-16.56 MPa. The angle of the maximum main stress with coronal section did not exceed 4 degrees.

[Voice rehabilitation with double-valve voice prosthesis after laryngectomy]

Between March 1993 and November 1996, 97 laryngectomized patients underwent voice rehabilitation with prostheses designed by ourselves. Of these patients, 84 were males and 13 females. The age ranged from 35 to 78 years. 20 cases had the prosthesis inserted during the laryngectomy operation (first stage), while other 77 cases were inserted after the laryngectomies (second stage). The results showed that all of the patients had clear voice with their own local dialect. 34 of them could even sing songs. 68 cases had been followed-up for 2 years. All could speak during the effective time of the prosthesis and no misswallow occurred.

Human autoantibodies stabilize the quaternary structure of Ku antigen

OBJECTIVE

To examine humoral immune responses to the native Ku antigen and to evaluate the role of autoantibodies in stabilizing intermolecular contacts between the p70 and p80 Ku subunits.

METHODS

Recombinant free human p70 and p80 Ku subunits and p70/p80 heterodimers were expressed in Sf9 (insect) cells using baculovirus vectors. Affinity-purified recombinant human p70, p80, and p70/p80 dimer were studied by enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation to evaluate autoantibody specificities in sera from 58 patients with systemic autoimmune disease.

RESULTS

Anti-Ku antibodies were detected by ELISA or immunoprecipitation using K562 cell Ku antigen. All of the sera were reactive with the native recombinant p70, p80, or p70/p80 antigens: 47% were anti-p70+,anti-p80+ and 32% were anti-p70-,anti-p80+, but only 3% were anti-p70+,anti-p80-. Unexpectedly, 18% of the sera recognized the p70/p80 dimer but did not recognize native p70 or p80 alone. A subset of sera containing autoantibodies that prevent the dissociation of p70 from p80 by high salt and detergent treatment was identified; monoclonal antibody (MAb) 162, a murine anti-Ku MAb, displays the same property. Autoantibodies that stabilize the p70-p80 interaction were found most frequently in sera containing both anti-p70 and anti-p80 antibodies.

CONCLUSION

Autoantibodies to the native p80 subunit of Ku are more common than are anti-p70 antibodies. When anti-p70 antibodies were detected, they generally were found together with anti-p80. A novel type of autoantibody capable of stabilizing the p70/p80 heterodimer was identified in human sera for the first time. These "stabilizing" autoantibodies are found in sera containing both anti-p70 and anti-p80 antibodies, and also are produced by mice immunized with human Ku antigen. Autoimmunity to Ku may be initiated with an immune response to p80, followed by spreading to p70. We hypothesize that stabilizing antibodies could facilitate the spreading of autoimmunity from one subunit of Ku to another by altering the processing of p70 or p80 by antigen-presenting cells.

[Clinical study on effect of bushen shengxue paste in treating renal anemia patients]

OBJECTIVE

To evaluate the therapeutical mechanism of Bushen Shengxue Paste (BSSXP) on anemia.

METHODS

Chronic renal failure induced anemia patients were treated with BSSXP, clinical manifestation, anemia and renal function as indicators were observed in patients. The erythropoietin (EPO) and inhibition of colony-forming unit-erythrocyte (CFU-E) in patients' serum were determined by CFU-E in vitro.

RESULTS

The patients' symptoms, renal function and anemia were improved after administration with BSSXP 1-2 course. EPO in serum was slightly increased. The inhibition of CFU-E in patient's serum was significantly decreased.

CONCLUSIONS

BSSXP could improve the anemia degree, its mechanism might be through clearing the inhibitor of CFU-E in serum.

Fusion expression of mutated cecropin CMIV inE. coli

A cDNA coding mutated cecropin CMIV fromBombyx mori was synthesized according to its amino acid sequence usingE. coli biased codons. The gene was cloned into the fusion expression vector pEZZ318 and was expressed inE. coli HB101. The fusion protein produced was purified by affinity chromatography to yield 26 mg/L fusion product. The anti-bacterial activities of recombinant cecropin CMIV were recovered after cleavage by chemical method.

Expression of soluble, active human macrophage colony stimulating factor in Escherichia coli

Human macrophage colony stimulating factor (M-CSF) has been successfully overexpressed in Escherichia coli AD494 (DE3) with an expression level of approximate 26% of the total cellular proteins. The truncated human M-CSF gene encoding the amino-terminal 149 amino acids was subcloned into the prokaryotic expression vector pET11d under the control of the inducible T7 promoter. Nearly 40% of the recombinant protein was in the soluble fraction which showed obvious stimulating effects on mouse macrophage colony formation and had an M-CSF specific activity of approximately 1 x 10(6) units/mg soluble protein.

roughex down-regulates G2 cyclins in G1

Cell cycle arrest in G1 at the onset of patterning in the Drosophila eye is mediated by roughex. In roughex mutants, cells accumulate Cyclin A protein in early G1 and progress into S phase precociously. When Roughex is overexpressed in S/G2 cells, Cyclin A is mislocalized to the nucleus and degraded, preventing mitosis. Whereas Roughex inhibits Cyclin A accumulation, Cyclin E down-regulates Roughex protein in vivo. Roughex binds to Cyclin E and is a substrate for a Cyclin E-Cdk complex in vitro. These data argue that Roughex inhibits Cyclin A accumulation in early G1 by targeting Cyclin A for destruction. In late G1, Roughex is destabilized in a Cyclin E-dependent process, releasing Cyclin A for its role in S/G2.

[Cataract extraction combined intraocular lens implantation through corneal incision]

OBJECTIVE

We reported the clinical results of the extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation through a corneal incision.

METHODS

The ECCE with IOL implantation was performed through a stepped corneal incision within limbus 1.0-1.5 mm. The changes of intraocular pressure (IOP), endothelia and astigmatism were observed.

RESULTS

The IOP has no significant changes, and the rate of endothelial cells loss (12.55%) also has no significant differences compared with routine cataract extraction. The corneal astigmatism became 0.96 DC with the rule after operation.

CONCLUSION

For complicated cataract after trabeculectomy, uveitis with pupillary block, and serious diabetic cataract, the intraocular surgery through a corneal incision is effective and safe.

[Chromosome marker--2q- during carcinogenesis and development of human lung cancer]

OBJECTIVE

To study the cytogengtic alterations during the development of human lung cancer and to clarify the genetic basis of lung cancer.

METHODS

Using Fluorescence in situ Hybridization FISH, we have studied the chromosomal alterations of chromosome 2 and 3 in human bronchial epithelial cell line M, and 12 primary non-small cell lung cancer (NSCLC) specimens.

RESULTS

2q- was found in the later passage of human bronchial epithelial cell line M, and 3 out of 7 primary NSCLC specimens tested. 3p- being noted in five cases of 12 primary NSCLC patients examined was the first cytogenetic discovery and the most prominent abnormality in lung cancer. 2q- was rarely reported in human lung cancer before. But loss of heterozygosity by RFLP analysis for 2q had been reported in lung cancer.

CONCLUSION

2q- is also a common chromosome abnormality in human lung cancer. There would also be one or more putative tumor suppressor gene(s) on the long arm of chromosome 2. Loss of the gene(s) may contribute to the carcinogenesis of human non-small-cell lung cancer.

Two-dimensional Raman-Nath acousto-optic bistability by use of frequency feedback

From the frequency dependence of the optical transmission characteristics of Raman-Nath acoustic-optic diffraction, the dynamic equations and steady-state solutions of a two-dimensional Raman-Nath acousto-optic bistable system are derived. In this system, feedback is realized by use of a diffracted light beam to control the frequency of the acoustic-optic driver. The curves of light output versus input corresponding to several orders of the diffracted beams are obtained by theoretical analysis. They can all lead to bistability. The amount of hysteresis is a function of the order of the diffracted beam, the bias frequency, and the feedback coefficient. Experimental results are presented and compared with theoretical analyses.

Generation of H2O2 by human neutrophils and changes of cytosolic Ca2+ and pH of rat thymocytes in response to galactoside-binding proteins (lectins or immunoglobulins)

In contrast to plant agglutinins, biological activities of animal/human lectins are not well defined yet. Testing a panel of seven mammalian carbohydrate-binding proteins we have found that the dimeric lectin from chicken liver (CL-16) was a stimulator of H2O2 release from human neutrophils as well as effector for induction of cytosolic Ca2+ and pH increase in rat thymocytes. Activity of this lectin was comparable to potent galactoside-specific plant lectins such as Viscum album L. agglutinin. The activities of the tested plant lectins depended significantly on their nominal carbohydrate specificity as well as on the source. The results indicate that endogenous lectins may be involved in the regulation of neutrophil and lymphocyte functions by elicitation of selective biosignaling reactions.

Disease type-associated increases of the plasma levels and ligand expression for natural alpha- or beta-galactoside-binding immunoglobulin G subfractions in patients with lung cancer

The presence of natural carbohydrate-binding antibodies may play a role in host defence against malignant cells in addition to elicitation of an immune response by artificial carbohydrate antigens. Human serum contains immunoglobulin G(2) (IgG) fractions with selectivity to alpha- and to beta-galactosides, respectively, irrespective of the type of blood group of the donor. To determine whether these naturally occurring subfractions may have any relevance for tumor disease control, their binding to malignant cells was ascertained by cytofluorimetric assays in vitro with a number of human tumor cell lines of different histogenetic origin. The affinity of cell binding was comparable to that of binding to lactosylated or melibiosylated neoglycoconjugates as model ligands in solid-phase assays and K-D values were found to be in the range of 5-300 nM. Cross-reactivity of the anomer-selective subfractions to the other type of ligand was observed to be rather low. When the IgG contents of plasma samples of patients with diverse types of lung cancer were assessed, the concentrations of both galactoside-binding immunoglobulin G subfractions were significantly increased in association with presence of small cell lung carcinoma and of metastatic lesions to the lung without any marked change in the overall IgG plasma level. Such an apparently general enhancement was seen for patients with adenocarcinoma and included both subfractions with no impact on their percentage in the total IEC content. When detergent extracts of tumor and tumor-free specimens of the same patient were analyzed with the affinity purified antibody subfractions to comparatively determine ligand presentation, increases in sugar-inhibitable binding were especially noted for the tumor tissue of small cell lung carcinomas and apparently tumor-free samples of cases with lung metastasis. Material from other types of lung cancer revealed no significant indication for disease-related alterations with the exception of carcinoids. These data demonstrate that plasma levels and ligand expression for two types of natural galactoside-binding immunoglobulin G fractions can show nonuniform responses in patients within the class of lung cancer. They encourage to deliberately monitor these parameters of the natural carbohydrate-directed antibody fractions in cancer patients with various types of disease to clarify the clinical significance of respective malignancy-associated changes.

Microlamellar keratectomy for correction of high myopia

OBJECTIVE

To evaluate the preliminary results of high myopia correction by microlamellar keratectomy (MLK).

METHODS

Seventy-three eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00D to -32.00D (mean -18.45D +/- 6.18D). All the operations were performed with the special apparatus for MLK.

RESULTS

At 6 months after surgery, in the 73 eyes except 2 with new other symptoms, all the uncorrected visual acuity and corrected visual acuity were better than or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). No severe complications occurred during and after operation. The postoperative refractive status was stable.

CONCLUSIONS

MLK is effective to reduce high myopia and has some special advantages as compared with radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK). But influenced by several factors, the predictability of this procedure is merely fair. It is suggested that this kind of procedure must be done with excellent microsurgery equipments, microsurgical skills and much more clinical experience of managing corneal disorders.

[A prospective study on transfusion-related hepatitis C virus infection]

64 cases of blood recipients were followed-up for 6 months to study infection of hepatitis C virus. The infection rate of hepatitis C virus was 18.75% in total, including 8 cases of post-transfusion hepatitis C (PT-HC), 1 case of subclinical PT-HC, and 3 cases of anti-HCV sero conversion only. The time of initial ALT abnormality and anti-HCV sero conversion were 28 to 91 (51.9 +/- 20.9) days and 23 to 76 (42.4 +/- 15.9) days after blood transfusion respectively. There were 2 cases with cytomeglovirus infection and another 5 cases with unknown infectious agent were found in this study.

[Study on time-resolved fluorimetry of samarium]

In this paper, a simple and highly sensitive laser fluorimetric system is described, and the value of time discrimination for suppressing unwanted signals and decreasing the minimum detectable concentration is demonstrated. It is confirmed that time discrimination is very useful for ultratrale determination of fluorescent complex. This technique is successful with the combined use of a pulsed laser and a pulse-gate signal detection system for samarium complex. The linear range and the detectin limit of the method are 0. 01-10microg/ml and 3.3ng/ml, respectively. The RSD for Sm3+ (0. 5microg/ml) ( n =12) is 3.7%. The method was used to detemine samarium in rare earth mixtures. The recovery was in the range of 90.0-110.0%, and the mean recovery was 101.4% ( n = 6 )

The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats

The Arabidopsis NPR1 gene controls the onset of systemic acquired resistance (SAR), a plant immunity, to a broad spectrum of pathogens that is normally established after a primary exposure to avirulent pathogens. Mutants with defects in NPR1 fail to respond to various SAR-inducing treatments, displaying little expression of pathogenesis-related (PR) genes and exhibiting increased susceptibility to infections. NPR1 was cloned using a map-based approach and was found to encode a novel protein containing ankyrin repeats. The lesion in one npr1 mutant allele disrupted the ankyrin consensus sequence, suggesting that these repeats are important for NPR1 function. Furthermore, transformation of the cloned wild-type NPR1 gene into npr1 mutants not only complemented the mutations, restoring the responsiveness to SAR induction with respect to PR-gene expression and resistance to infections, but also rendered the transgenic plants more resistant to infection by P. syringae in the absence of SAR induction.

The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats

The Arabidopsis NPR1 gene controls the onset of systemic acquired resistance (SAR), a plant immunity, to a broad spectrum of pathogens that is normally established after a primary exposure to avirulent pathogens. Mutants with defects in NPR1 fail to respond to various SAR-inducing treatments, displaying little expression of pathogenesis-related (PR) genes and exhibiting increased susceptibility to infections. NPR1 was cloned using a map-based approach and was found to encode a novel protein containing ankyrin repeats. The lesion in one npr1 mutant allele disrupted the ankyrin consensus sequence, suggesting that these repeats are important for NPR1 function. Furthermore, transformation of the cloned wild-type NPR1 gene into npr1 mutants not only complemented the mutations, restoring the responsiveness to SAR induction with respect to PR-gene expression and resistance to infections, but also rendered the transgenic plants more resistant to infection by P. syringae in the absence of SAR induction.

Control of G1 in the developing Drosophila eye: rca1 regulates Cyclin A

In the developing eye of Drosophila melanogaster, cells become synchronized in the G1 phase of the cell cycle just prior to the onset of cellular differentiation and morphogenesis. In roughex (rux) mutants, cells enter S phase precociously because of ectopic activation of a Cyclin A/Cdk complex in early G1. This leads to defects in cell fate and pattern formation, and results in abnormalities in the morphology of the adult eye. A screen for dominant suppressors of the rux eye phenotype led to the identification of mutations in cyclin A, string (cdc25), and new cell cycle genes. One of these genes, regulator of cyclin A (rca1), encodes a novel protein required for both mitotic and meiotic cell cycle progression. rca1 mutants arrest in G2 of embryonic cell cycle 16 with a phenotype very similar to cyclin A loss of function mutants. Expression of rca1 transgenes in G1 or in postmitotic neurons promotes Cyclin A protein accumulation and drives cells into S phase in a Cyclin A-dependent fashion.

Comparative cross-linking activities of lactose-specific plant and animal lectins and a natural lactose-binding immunoglobulin G fraction from human serum with asialofetuin

Plant and animal lectins bind and cross-link certain multiantennary oligosaccharides, glycopeptides, and glycoproteins. This can lead to the formation of homogeneous cross-linked complexes, which may differ in their stoichiometry depending on the nature of the sugar receptor involved. As a precisely defined ligand, we have employed bovine asialofetuin (ASF), a glycoprotein that possesses three asparagine-linked triantennary complex carbohydrate chains with terminal LacNAc residues. In the present study, we have compared the carbohydrate cross-linking properties of two Lac-specific plant lectins, an animal lectin and a naturally occurring Lac-binding polyclonal immunoglobulin G subfraction from human serum with the ligand. Quantitative precipitation studies of the Lac-specific plant lectins, Viscum album agglutinin and Ricinus communis agglutinin, and the Lac-specific 16 kDa dimeric galectin from chicken liver demonstrate that these lectins form specific, stoichiometric cross-linked complexes with ASF. At low concentrations of ASF, 1:9 ASF/lectin (monomer) complexes formed with both plant lectins and the chicken lectin. With increasing concentrations of ASF, 1:3 ASF/lectin (monomer) complexes formed with the lectins irrespective of their source or size. The naturally occurring polyclonal antibodies, however, revealed a different cross-linking behavior. They show the formation of 1:3 ASF/antibody (per Fab moiety) cross-linked complexes at all concentrations of ASF. These studies demonstrate that Lac-specific plant and animal lectins as well as the Lac-binding immunoglobulin subfraction from specific stoichiometric cross-linked complexes with ASF. These results are discussed in terms of the structure-function properties of multivalent lectins and antibodies.

Autoantibodies to ribosomal P antigens with immune complex glomerulonephritis in SJL mice treated with pristane

BALB/c ByJ mice develop a lupus-like syndrome characterized by anti-nRNP/Sm and Su autoantibodies and immune complex glomerulonephritis after a single i.p. pristane injection. In contrast, mercuric chloride induces anti-fibrillarin Abs only in SJL and other H-2s mice, and not in BALB/c (H-2d) mice. In the present study, the specificities of autoantibodies induced by pristane and HgCl2 were compared in SJL and BALB/c mice to examine whether these strains are "programmed" to make different sets of autoantibodies in response to nonspecific immune stimulation. Unexpectedly, the predominant autoantibodies induced by pristane in SJL mice were neither those characteristic of HgCl2-treated SJL mice nor those associated with pristane-induced disease in BALB/c mice but, rather, anti-ribosomal P, another lupus-related specificity. The autoantibodies were strongly reactive with the C-terminal 22 amino acids of the ribosomal P2 protein, indicating that they exhibited similar fine specificities to anti-P Abs in human SLE and MRL/Ipr mice. Like BALB/c mice, pristane-treated SJL mice developed severe glomerulonephritis characterized by proteinuria, mesangial proliferation, and glomerular immune complex deposits. This is the first evidence that the induction of a lupus-like syndrome by pristane is not restricted to BALB/c mice. The predominance of anti-P Abs in SJL mice contrasts sharply with the predominance of anti-nRNP/Sm and Su, in pristane-treated BALB/c mice, even though the renal lesions were similar in both strains. The data suggest that H-2s does not program mice to produce anti-fibrillarin Abs in response to nonspecific immune stimulation, arguing that autoantibody induction by pristane involves Ag-specific mechanisms.

Autoantibodies to ribosomal P antigens with immune complex glomerulonephritis in SJL mice treated with pristane

BALB/c ByJ mice develop a lupus-like syndrome characterized by anti-nRNP/Sm and Su autoantibodies and immune complex glomerulonephritis after a single i.p. pristane injection. In contrast, mercuric chloride induces anti-fibrillarin Abs only in SJL and other H-2s mice, and not in BALB/c (H-2d) mice. In the present study, the specificities of autoantibodies induced by pristane and HgCl2 were compared in SJL and BALB/c mice to examine whether these strains are "programmed" to make different sets of autoantibodies in response to nonspecific immune stimulation. Unexpectedly, the predominant autoantibodies induced by pristane in SJL mice were neither those characteristic of HgCl2-treated SJL mice nor those associated with pristane-induced disease in BALB/c mice but, rather, anti-ribosomal P, another lupus-related specificity. The autoantibodies were strongly reactive with the C-terminal 22 amino acids of the ribosomal P2 protein, indicating that they exhibited similar fine specificities to anti-P Abs in human SLE and MRL/Ipr mice. Like BALB/c mice, pristane-treated SJL mice developed severe glomerulonephritis characterized by proteinuria, mesangial proliferation, and glomerular immune complex deposits. This is the first evidence that the induction of a lupus-like syndrome by pristane is not restricted to BALB/c mice. The predominance of anti-P Abs in SJL mice contrasts sharply with the predominance of anti-nRNP/Sm and Su, in pristane-treated BALB/c mice, even though the renal lesions were similar in both strains. The data suggest that H-2s does not program mice to produce anti-fibrillarin Abs in response to nonspecific immune stimulation, arguing that autoantibody induction by pristane involves Ag-specific mechanisms.

Molecular dynamics-derived conformation and intramolecular interaction analysis of the N-acetyl-9-O-acetylneuraminic acid-containing ganglioside GD1a and NMR-based analysis of its binding to a human polyclonal immunoglobulin G fraction with selectivity for O-acetylated sialic acids

The influence of 9-O-acetylation of GD1a, yielding GD1a (eNeu5,9Ac2) with a 9-O-acetylated sialic acid moiety linked to the outer galactose residue, on the spatial extension and mobility of the carbohydrate chain and on recognition by a natural human antibody is analysed. To study a potential impact of the O-acetyl group on the overall conformation of the carbohydrate chain, molecular dynamics (MD) simulations of oligosaccharide chain fragments of increasing length starting from the non-reducing end have been carried out for the first time in this study. They revealed a considerable loss in chain flexibility after addition of the internal N-acetylneuraminic acid onto the chain. Besides MD calculations with different dielectric constants, the conformational behaviour of the complete oligosaccharide chain of the 9-O-acetylated GD1a ganglioside was simulated in the solvents water and dimethyl sulfoxide. These solvents were also used in NMR measurements. The results of this study indicate that 9-O-acetylation at the terminal sialic acid does not influence the overall conformation of the ganglioside. An extended interaction analysis of energetically minimized conformations of GD1a (eNeu5,9Ac2) and GD1a, obtained during molecular dynamics simulations, allowed assessment of the influence of the different parts of the saccharide chains on spatial flexibility. Noteworthy energetic interactions, most interestingly between the 9-O-acetyl group and the pyranose ring of N-acetylgalactosamine, were ascertained by the calculations. However, the strength of this interaction does not force the ganglioside into a conformation, where the 9-O-acetyl group is no longer accessible. Binding of GD1a (eNeu5,9Ac2) to proteins, which are specific for 9-O-acetylated sialic acids, should thus at least partially be mediated by the presence of this group. To experimentally prove this assumption, a NMR study of 9-O-acetylated GD1a in the presence of an affinity-purified polyclonal IgG fraction from human serum with preferential binding to 9-O-acetylated sialic acid was performed. The almost complete disappearance of the intensity of the 9-O-acetyl methyl signal of the GD1a (eNeu5,9Ac2) clearly indicates that the assumed interaction of the 9-O-acetyl group with the human protein takes place.

High-level expression of active human plasminogen activator inhibitor type 1 (PAI-1) in E. coli

Plasminogen activator inhibitor 1 (PAI-1) is an important regulator of plasminogen activation, which inhibits both tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). The DNA sequence encoding mature PAI-1 protein was inserted into an inducible expression vector. This gene was highly expressed to produce a soluble active protein in E. coli cells. The amount of the recombinant protein was up to 20% of total cellular protein. By efficient purification with a yield of about 15-20%, the recombinant protein could be purified to homogeneity with its specific activity up to 6.1 x 10(4) (uPA) IU/mg. Its inhibitory activity declined during incubation at 37 degrees C with a half life of about 2 hr.