Concurrent inhibition and excitation of phrenic motoneurons during inspiration: phase-specific control of excitability

The movements that define behavior are controlled by motoneuron output, which depends on the excitability of motoneurons and the synaptic inputs they receive. Modulation of motoneuron excitability takes place over many time scales. To determine whether motoneuron excitability is specifically modulated during the active versus the quiescent phase of rhythmic behavior, we compared the input-output properties of phrenic motoneurons (PMNs) during inspiratory and expiratory phases of respiration. In neonatal rat brainstem-spinal cord preparations that generate rhythmic respiratory motor outflow, we blocked excitatory inspiratory synaptic drive to PMNs and then examined their phase-dependent responses to superthreshold current pulses. Pulses during inspiration elicited fewer action potentials compared with identical pulses during expiration. This reduced excitability arose from an inspiratory-phase inhibitory input that hyperpolarized PMNs in the absence of excitatory inspiratory inputs. Local application of bicuculline blocked this inhibition as well as the difference between inspiratory and expiratory firing. Correspondingly, bicuculline locally applied to the midcervical spinal cord enhanced fourth cervical nerve (C4) inspiratory burst amplitude. Strychnine had no effect on C4 output. Nicotinic receptor antagonists neither potentiated C4 output nor blocked its potentiation by bicuculline, further indicating that the inhibition is not from recurrent inhibitory pathways. We conclude that it is bulbospinal in origin. These data demonstrate that rapid changes in motoneuron excitability occur during behavior and suggest that integration of overlapping, opposing synaptic inputs to motoneurons is important in controlling motor outflow. Modulation of phasic inhibition may represent a means for regulating the transfer function of PMNs to suit behavioral demands.

[Removal of YY1 binding sites in HPV 16 LCR increases viral transforming activities on mouse fibroblasts]

OBJECTIVE

To study the effect of removal of YY1 binding sites within the LCR region of HPV 16 on viral transforming activity.

METHODS

Previously we had generated new plasmids carrying HPV 16 whole genome, which contained naturally occurred mutated LCR sequences. The viral transforming abilities on mouse fibroblasts were evaluated in anchorage-independent assays, while the expression and activity of YY1 protein in fibroblasts were tested with EMSA and luciferase assays.

RESULTS

YY1 protein was expressed in mouse fibroblasts C127, with ability for DNA binding and repression on P97 activity. Both HPV 16 wild-type DNA and mutated DNAs were transfected into C127 cells and spread to the soft-agarose mediums after selecting with G 418. The growth numbers of the cells transfected with mutated HPV 16 DNAs were 2-10 fold more than that with wild-type HPV 16 DNA.

CONCLUSION

Like in epithelial cells or cell lines, transcription regulator YY1 is widely expressed in rodent fibroblasts. Removal of YY1 binding motifs can elevate in the context of the whole genome, the anchorage independent growth ability and the transforming capacity of HPV 16 on the mouse fibroblasts.

[Phacoemulsification and posterior chamber intraocular lens implantation in high myopia]

OBJECTIVE

To evaluate the therapeutic effect of phacoemulsification and posterior chamber intraocular lens (IOL) implantation in high myopia.

METHODS

Phacoemulsification with implantation of a foldable IOL or a PMMA rigid IOL was performed on 28 eyes of 21 patients with senile, complicated or congenital cataracts through a 3.2 mm small scleral tunnel incision or through a 5.5 mm incision respectively. The average age of the patients was 51.32 years (21 - 70 years). The mean axial length was (27.56 +/- 1.21) mm (26.00 - 33.41 mm). The mean keratometry was (43.38 +/- 1.36) D (42.00 - 46.54 D). The mean diopter of IOL was (+ 9.59 +/- 3.65) D (+ 4.00 - + 15.00 D).

RESULTS

Postoperatively, the uncorrected or corrected visual acuity 0.5 or better at 1 day, 1 week, 1 month and 3 months was in 63.6%, 86.4%, 95.5% and 95.2% patients respectively; the patients having achieved the best visual acuity of 1.0 or better were accounted for 9.1%, 31.8%, 50.0% and 57.1% respectively.

CONCLUSIONS

Phacoemulsification and the posterior chamber IOL implantation offers the advantages of rapid and better rehabilitation of visual acuity and more stabilization of postoperative astigmatism in patients with high myopia; whereas for eyes with the axial lengths over 30 mm, the recovery of the visual acuity was less satisfactory.

[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.