[Effect of pentoxifylline on promoter activity of human alpha 1(I) procollagen gene]

OBJECTIVE

To study the effect of pentoxifylline (PTX) on promoter activity of human alpha 1(I) procollagen (COL1A1) gene and the influence of PTX on the promoter activity induced by insulin-like growth factor 1 and insulin.

METHODS

The constructs of pCOLH2.5 containing -2483 approximately +42bp of the procollagen gene and chloramphenicol acetyltransferase (CAT) as reporter gene were transiently transfected into human skin fibroblasts. The cells were subsequently treated with PTX or IGF-1 or insulin, or PTX plus IGF-1 or insulin. The CAT activity was assessed 24h after PTX and the cytokines added.

RESULTS

PTX of 0.4 mmol/L, 2 mmol/L, and 10 mmol/L decreased the CAT activity of pCOLH 2.5 to 82%+/-9%, 58%+/-8%, and 32%+/-13% of the control level, respectively. IGF-1 and insulin increased the activity of the construct. PTX could inhibit the CAT activity of pCOLH2.5 induced by IGF-1 and insulin.

CONCLUSIONS

These studies indicate that PTX downregulates the promoter activity of the human COL1A1 gene, while IGF-1 and insulin upregulates it. PTX can inhibit the promoter activity induced by IGF-1 and insulin.

Transcatheter closure of secundum atrial septal defect with a new self-expanding nitinol double disk device (Amplatzer device): experience in Nanjing

PURPOSE

Various devices have been developed for the transcatheter closure of secundum atrial septal defect (ASD II) to avoid the morbidity, discomfort, and thoracotomy scar associated with surgical closure. The purpose of this study was to evaluate the safety and efficacy of the Amplatzer septal occluder for transcatheter closure of ASD II.

PATIENTS AND METHODS

Only patients who were clinically diagnosed with ASD II were selected. The anatomy of ASD had to meet certain echocardiographic criteria. Under the guidance of echocardiography and fluoroscopy, the implantation of the device was accomplished as recommended by the manufacturer.

RESULTS

Thirty patients (median age 18.4 years) with an ASD II underwent transcatheter closure. Procedure time ranged from 30-200 minutes and fluoroscopy time from 10-50 minutes. The diameter of the ASD measured by echocardiography ranged from 13-25 mm, while both the stretched diameters of the ASDs and the sizes of the devices ranged from 18-34 mm. The successful placement rate was 100%. The residual shunt rate was 100% immediately after device implantation and 10% after 24 hours. After 3 months, 3.3% of the patients had a (trivial) residual shunt. The device did not affect the surrounding structures of ASD. No embolization of the device occurred.

CONCLUSION

The Amplatzer device designed for the closure of ASD II can be implanted easily and also is retrievable. Due to a low ratio of residual shunt and few complications, this device is a good choice for transcatheter closure of ASD II. Long-term follow-up will be required for widespread clinical use.

Molecular epidemiology of respiratory syncytial virus

OBJECTIVE

To determine the epidemiologic pattern of subgroups A and B and genotypes of respiratory syncytial virus (RSV) during two noncontinuous epidemics during 1990-1991 and 1997-1998 in Beijing.

METHODS

Nasopharyngeal secretion (NPS) samples of RSV positive or RSV isolates tested by indirect immunofluorescence (IIF) assay were classified into subgroups A and B. Isolates of RSV were divided into at least six different lineages, designated NP1-NP6, by restriction mapping of the N gene. Np1, 3 and 6 were given by subgroup B isolates, while NP2, 4 and 5 were given by subgroup A isolates. Strains of subgroup A were further subdivided into six lineages SHL1-SHL6 on the basis of the SH gene sequence. SH lineages were closely related to each other and to NP1-NP6. Strains of SHL1, 3 and 4 were closely related and belonged to NP2, SHL2 and 6 to NP4, and SHL5 to NP5.

RESULTS

Of 145 RSV NPS samples from the 1997-1998 epidemic, 83 (57.2%) were of subgroup B RSV positive, 62 (42.8%) of subgroup A RSV positive. The rate of occurrence of subgroup A to B strains was about 1:1.3. Two of 10 isolates during the epidemic were subgroup A strains, whereas 8 were subgroup B strains. The rate of occurrence of subgroup A to B strains was 1:4. Eight subgroup A strains of 10 isolates from the 1990-1991 epidermic were dominant; the proportion of subgroup A to B strains was 4:1. With 10 RSV isolates in 1997-1998, all 2 subgroup A strains gave N gene fragment restriction pattern NP4, and fell into SH lineage SHL2, whereas 8 subgroup B strains all belonged to NP3. All 8 subgroup A isolates from the 1990-1991 epidemic gave pattern NP4, and fell into SHL2, while 2 subgroup B strains all belonged to NP3. The classification of subgroups A and B deduced from NP patterns corresponded to the definition of these subgroups by monoclonal antibodies.

CONCLUSIONS

These observations confirm that subgroups A and B or multiple lineages of RSV co-circulated in Beijing, but different genome types predominated each year. Moreover, very similar viruses were isolated up to more than 5 years ago, indicating that despite apparent diversity of the subgroup A strains, the separate lineages might be relatively stable.

[Carcinoma of kidney collecting duct: an analysis of 10 cases]

OBJECTIVE

To study the clinicopathologic characteristics of renal collecting duct carcinoma (CDC).

METHODS

A retrospective study was done in 10 cases of CDC.

RESULTS

Among 466 cases of renal cell carcinoma admitted in our Institute between January 1989 and June 30, 1999, 10(2.1%) cases of CDC were identified. Seven presented with gross hematuria and 3 with abdominal pain. Radical nephrectomy was done in 9 patients, enucleation of tumor in one. The primary tumor was located predominantly in the renal medulla. Histologic examination showed prominent tubular or tubulopapillary structures. Sarcomatoid carcinoma, cystadenocarcinoma, nests and cords of tumor cells in desmoplastic stroma were identified in some cases. High molecular weight cytokeratin 34 beta E12 was positive in 8 cases and peanut agglutinin in 7 cases. According to Fuhrman's nuclear grade, one was in G2, 4 were in G3 and 5 in G4. Six patients died of metastases within 3 to 23 months (mean 13.3 months), one died of heart disease with tumor free after 19 months, two survived with tumor free for 14 months and 39 months, respectively, one lost from follow-up.

CONCLUSION

CDC is a distinctive renal cell carcinoma with prominent clinical appearance and progressive clinical course.

Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP

Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.

Directed evolution of operon of trehalose-6-phosphate synthase/phosphatase from Escherichia coli

Trehalose is a nonspecific protective agent for biomacromolecules. Trehalose-6-phosphate synthase (OtsA)/phosphatase (OtsB), which is encoded by the gene operon otsBA located at -42 of the Escherichia coli genome, is the main enzyme system that catalyzes the synthesis of trehalose in E. coli. We cloned the operon and modified it by directed evolution. Unlike in the previously reported work, we modified the whole operon and screened the positive mutant simultaneously. Thus we believe that the gene complex solves the negative effects between two enzymes if one of them diversifies its structure or functions and finds the form most suitable for trehalose synthesis. It thus mimics the natural process, in which the functional improvement of organisms is related to alterations in coordinated enzymes. The evolution procedure was carried out in a sequence of error-prone PCR, shuffling PCR, and then strict screening of the mutants. After screening of a library of more than 4000 colonies, about 15 positive colonies were analyzed, resulting in a higher concentration of trehalose than control. One of them, E. coli TS7, shows 12.3-fold higher trehalose synthesis ability than E. coli DH5alpha. In contrast, we introduced the cDNA sequence of the tps1 gene from Saccharomyces cerevisiae, which has 54% identity with the gene otsA, as one of the templates in shuffling PCR. By hybrid evolution and screening, we obtained 10 positive colonies with higher concentrations of trehalose than control. E. coli TS22 appears to have 5.3-fold higher trehalose synthesis ability than E. coli DH5alpha and 1.6-fold more than E. coli DEF3(pOTS11). This result demonstrated that coevolution and hybrid evolution, as powerful protocols in protein engineering, are effective in modifying enzyme. It indicates that repeating the process of genomic evolution in nature is feasible.

Blocking intercellular adhesion molecule-1 on human epithelial cells decreases respiratory syncytial virus infection

The respiratory syncytial virus (RSV) causes potentially fatal lower respiratory tract infection in infants. The molecular mechanism of RSV infection is unknown. Our data show that RSV colocalizes with intercellular adhesion molecule-1 (ICAM-1) on the HEp-2 epithelial cell surface. Furthermore, a neutralizing anti-ICAM-1 mAb significantly inhibits RSV infection and infection-induced secretion of proinflammatory chemokine RANTES and mediator ET-1 in HEp-2 cells. Similar decrease in RSV infection is also observed in A549, a type-2 alveolar epithelial cell line, and NHBE, the normal human bronchial epithelial cell line when pretreated with anti-ICAM-1 mAb prior to RSV infection. Incubation of virus with soluble ICAM-1 also significantly decreases RSV infection of epithelial cells. Binding studies using ELISA indicate that RSV binds to ICAM-1, which can be inhibited by an antibody to the fusion F protein and also the recombinant F protein can bind to soluble ICAM-1, suggesting that RSV interaction with ICAM-1 involves the F protein. It is thus concluded that ICAM-1 facilitates RSV entry and infection of human epithelial cells by binding to its F protein, which is important to viral replication and infection and may lend itself as a therapeutic target.

[Decomposition of aqueous sodium pentachlorophenolate (PCP-Na) by using TiO2 coating photocatalyst]

Titanium dioxide (TiO2) photocatalysts were coated on hollow glass beads by sodium silicate (Na2SiO3.9H2O) solution. The coated catalysts were characterized by BET, XRD. Their photoactivity were examined using photocatalytic degradation of sodium pentachlorophenolate(PCP-Na) and glucose solution. The impact of catalysts dosage, PCP-Na initial concentration, initial pH and oxygen concentration on reaction kinetics were also studied in detail. The experiments illustrated that the performance of C3-type catalysts was satisfactory. Conditions of the experiments were following: The initial concentration of PCP-Na and CODCr were 10 mg.L-1 and 400 mg.L-1, respectively, and illumination time was 2 hours and catalysts dosage was 2 g.L-1, the removal rates of CODCr and PCP-Na were above 65% and 92% respectively. Optimum dosage of C3-type catalysts was 2-2.5 g.L-1, DO was no less than 3 mg.L-1.

Pulmonary sequestration: three dimensional dynamic contrast-enhanced MR angiography and MRI

In order to evaluate the diagnostic value of three-dimensional contrast-enhanced MR angiography and MRI for pulmonary sequestration, 5 patients with pulmonary sequestration underwent 3D fast imaging by steady state precession (FISP) with a contrast medium and breath holding following chest radiography, CT and MR scans. The reconstructed MR angiography was performed using maximum intensity projection (MIP) and multiplanar reconstruction (MPR) techniques. It was found that the chest radiography showed pulmonary sequestration as a persistent area of opacity in the posterior basal segment of the left lower lobe, which was close to mediastinum in 2 cases and close to diaphragma in 3 cases. CT revealed a soft issue mass beyond descending aorta and lobar emphysema around the pulmonary sequestration. And the supplying vessel was documented in 2 cases on enhanced CT. MRI demonstrated a hyperintensity mass with respect to normal lung parenchyma on T1WI and T2WI, and the origin of the supplying vessel in 3 cases. The reconstructed CE MRA using MIP or MRP techniques clearly showed the supplying vessel and its course, branches as well as draining vessels. It was concluded that 3D CE MRA of demonstrating the supplying and draining vessels to pulmonary sequestration, together with plain MRI, can provide a diagnosis and aid in surgical planning without the need for DSA.

Anti-viral activity of hairpin ribozyme directed against HBV core region in vitro

To study the preparation and cleavage of hairpin ribozyme (HpRz) directed against the transcript of HBV core region in vitro, HRz gene designed by computer targeting the transcript of HBV core gene was cloned into the vector p1.5 between 5'-cis-Rz and 3'-cis-Rz. 32P-labeled HpRz transcript proved whether the vector fit for the preparation of hairpin ribozyme. 32P-labeled pKC transcript containing HBV core region as targets-RNA was transcribed by using T7 RNA polymerase and purified by PAGE. Cold HpRz transcript was incubated with 32P-labeled target-RNAs under different conditions and radioautographed after denaturing polyacrylamide gel electrophoresis. The results showed that HpRz had the ability of cleavage at 37 degrees C and 12 mmol/L MgCl2 and the design of ribozyme was correct. It is concluded that HpRz prepared in vitro possesses specific catalytic activity, indicating that it is possible for HpRz to intracellularly inhibit the replication of HBV. It may be developed into a nucleic acid drug in the treatment of hepatitis B in the future.

Determination of internucleotide (h)J(HN) couplings by the modified 2D J(NN)-correlated [(15)N, (1)H] TROSY

Recent developments in the direct observation of J couplings across hydrogen bonds in proteins and nucleic acids provide additional information for structure and function studies of these molecules by NMR spectroscopy. A J(NN)-correlated [(15)N, (1)H] TROSY experiment proposed by Pervushin et al. (Proc. Natl. Acad. Sci. USA 95, 14147-14151, 1998) can be applied to measure (h)J(HN) in smaller nucleic acids in an E.COSY manner. However, it cannot be effectively applied to large nucleic acids, such as tRNA(Trp), since one of the peaks corresponding to a fast relaxing component will be too weak to be observed in the spectra of large molecules. In this Communication, we proposed a modified J(NN)-correlated [(15)N, (1)H] TROSY experiment which enables direct measurement of (h)J(HN) in large nucleic acids.

Near-infrared spectrophotometric determination of tri- and tetrapeptides

A new method based on the near infrared technique has been developed for the noninvasive and nondestructive determination of the identity and sequences of amino acid residues in small peptides. The method is capable of distinguishing not only peptides with very similar structures (e.g., Gly-Ala-Ala, Gly-Ala-Leu, Leu-Gly-Gly and Gly-Leu-Leu-Gly, Gly-Leu-Gly-Gly, Gly-Gly-Ala-Gly) but also peptides with the same amino acid residues but different sequences (e.g., Gly-Ala-Ala, Ala-Gly-Ala, Ala-Ala-Gly and Gly-Gly-Gly-Ala, Gly-Gly-Ala-Gly).

[Influence of mannitol on early enlargement of hematoma in hypertensive cerebral hemorrhage]

OBJECTIVE

To probe into the influence of mannitol on early enlargement of hematoma in hypertensive cerebral hemorrhage, and to discuss how to use mannitol correctly.

METHODS

93 patients with hypertensive supratentorial non-thalamic cerebral hemorrhage and light intracranial hypertension, and with less than 30 ml of hematoma volume determined by cranial CT within 6 h after the onset were randomly divided into a group in which mannitol was used (n = 46) or a group in which mannitol was not used (n = 47) within 24 h. Cranial CT was redone at 48 h. If the volume of hematoma increased by 33%, it was named early enlargement of hematoma. The influence of using mannitol within 24 h after the onset on early enlargement of hematoma was analyzed.

RESULTS

14(14/46) patients in the group in which mannitol was used within 24 h after the onset had early enlargement of hematoma, yet 4(4/47) patients in the group without mannitol had hematoma enlargement. There was significant difference between them (P < 0.01). No significant difference was seen between the integral of nerve function defect in the two groups when CT was done at the first time (P > 0.05). When CT was redone, the integral of nerve function defect in the group with mannitol used within 24 h was markedly higher than that in the group without mannitol (P < 0.05). 5(5/46) patients died in the former group and 1(1/47) in the latter.

CONCLUSION

Improper use of mannitol within 24 h after the onset may increase the incidence of early enlargement of hematoma in patients with hypertensive cerebral hemorrhage, and exacerbate the patient's condition. For patients with hypertensive cerebral hemorrhage with light intracranial hypertension, especialy those within 24 h after the onset, mannitol should not be used blindly, in case that it enlarges the hematoma and exacerbates patient's condition.

[Determination of the composition distribution of polymer blend films by using microscopic FTIR]

In this paper, PS/PC blend film (about 120 microns thick) and PS/PMMA (about 90 microns thick) blend film were prepared by evaporation the solvent very slowly from polymer blend solution. Different FTIR methods were used to determine the composition distribution along the vertical direction of the films. PS/PC film was firstly sectioned by ultramicrotomy, then the vertical section was measured to determine the composition of every 16 microns width unit from the surface-side to the bottom-side by Microscopic transmission-FTIR. The results showed that the concentration of PS was significantly greater in the vicinity of the surface of the film than that in the bulk, i.e., the component of PS enriched to the surface. Focusing the reflecting infrared light on different layer of the film, we can detect the composition of the different depth region in the PS/PMMA blend film. As the result, PMMA aggregated to the bottom of the film. It was considered that this effect was related to the different affinity and wetting prosperities of the blend component to the substrate or air.

Refinement of the locus for autosomal dominant hereditary gingival fibromatosis (GINGF) to a 3.8-cM region on 2p21

Hereditary gingival fibromatosis (HGF, MIM 135300; approved gene symbol GINGF) is an oral disease characterized by enlargement of gingiva. Recently, a locus for autosomal dominant HGF has been mapped to an 11-cM region on chromosome 2p21. In the current investigation, we genotyped four Chinese HGF families using polymorphic microsatellite markers on 2p21. The HOMOG test provided evidence for genetic homogeneity, with evidence for linkage in four families (heterogeneity versus homogeneity test HOMOG, chi(2) = 0. 00). A cumulative maximum two-point lod score of 5.04 was produced with marker D2S390 at a recombination frequency of &theta; = 0 in the four linked families. Haplotype analysis localized the hereditary gingival fibromatosis locus within the region defined by D2S352 and D2S2163. This region overlaps by 3.8 cM with the previously reported HGF region. Single-strand conformation polymorphism and sequence analysis of the coding region of cytochrome P450 1B1 (CYP1B1) excluded it as a likely candidate gene.

[Study on typing of respiratory syncytial viruses]

OBJECTIVE

To determine the epidemiologic patterns of subgroups A and B and genotypes of respiratory syncytial viruses (RSV) during two uncontinuously epidemic years from 1990 to 1991 and 1997 to 1998 in Beijing.

METHODS

Nasopharyngeal secretion (NPS) samples of RSV positive or BSV isolates tested by indirect immunofluorescent (IIF) assay were classified into subgroups A and B. Also, isolates of RSV were divided into at least six different lineages, designated NPl-6, by restriction mapping of the N gene. NP l, 3 and 6 were given by subgroup B isolates, while NP2, 4 and 5 were given by subgroup A isolates. Strains of subgroup A were further subdivided into six lineages SHL 1-6 on the basis of the SH gene sequence. SH lineages were closely related to each other and to NP 1-6. Strains of SHL 1,3, and 4 were closely related and belonged to NP2, SHL 2 and 6 to NP4 and SHL5 to NP5.

RESULTS

Of 145 RSV NPS samples from the winter 1997 to the spring 1998, 83(57.2%) were subgroup B strains, 62(42.8%) were sub-group A strains, the rate of occurrence of subgroup A to B strains was about 1:1.3. Two of 10 isolates of 1997-1998 offered by viral department of research institute of Pediatrics were subgroup A strains, whereas 8 were subgroup B strains, the rate of occurrence of subgroup A to B strains was 1:4. Eight subgroup A strains of 10 isolates from the 1990-1991 epidemic were dominant, the proportion of subgroup A to B strains was 4:1. of 10 BSV isolates in 1997-1998, all 2 subgroups A strains gave N gene fragment restriction pattern NP4, and fell into SH lineage SHL2, whereas 8 subgroup B strains all belonged to NP3. All 8 subgroup A isolates from the 1990-1991 epidemic gave pattern NP4, and fell into SHL2, while 2 subgroups B strains all belonged to NP3. The classification of subgroups A and B deduced from NP patterns was corresponded to the definition of these subgroups by monoclonal antibodies.

CONCLUSIONS

These observations confirmed that subgroups A and B or multiple lineages of BSV co-circulated in Beijing, but different genomic types predominated each year. Moreover, very similar viruses were isolated up to more than 5 years ago, indicating that despite apparent diversity of the subgroup A strains, the separate lineages might be relatively stable.

A J-multiplied HMQC (MJ-HMQC) experiment for measuring (3)J(HNHalpha) coupling constants

The J-multiplied HSQC experiment (MJ-HSQC: S. Heikkinen et al., J. Magn. Reson 137, 243 (1999)) amplifies J coupling constants m times and allows direct observation of the (3)J(HNHalpha) coupling constants of peptides and proteins (<10 kDa). The drawbacks to this method are line broadening in the f(1)-dimension and lower sensitivity. In the J-multiplied HMQC (MJ-HMQC) experiment described here, the PEP-HSQC pulse sequence is replaced by a sensitivity-enhanced HMQC section, and the total decay time for the J-coupling and the chemical shift evolution is shortened by a period of t(1). This experiment affords narrower linewidth and enhances the sensitivity by 34%, on an average of 105 well-isolated peaks, when compared with the MJ-HSQC experiment.

Injury detection for central nervous system via EEG with higher order crossing-based methods

Higher order crossing (HOC) is a powerful tool for time series analysis. Two HOC-based EEG analysis methods are developed for brain injury detection and quantification. The first method explores EEG spectrum characteristics via an estimate of the dominant frequency of a pre-processed EEG signal. The second method is based on the norm of the AHOC, an HOC obtained from the alpha-filter prefiltered EEG signal. Both methods are shown to be effective in detecting hypoxic/asphyxic injuries as well as assessing the severity of the injury.

Sensitivity enhancement of HCACO by using an HMQC magnetization transfer scheme

Previous theoretical calculations have demonstrated that the multiquantum relaxation rate of (1)H(alpha)-(13)C(alpha)(R(MQ)) is, on average, 1.3 +/- 0.4 or 1.7 +/- 0.6 times slower than the single-quantum relaxation rate of (13)C(alpha)(R(C)) for a sample with or without, respectively, amide protons. By taking advantage of this fact and by using the PEP sensitivity enhancement scheme, an HMQC version of the HCACO experiment has been developed. We demonstrate that this new experiment is 23 and 55% more sensitive than the original HSQC version of the HCACO experiment, at constant times of 7 and 27 ms, respectively, for a sample of the BC domain of the ciliary neurotrophic factor receptor protein dissolved in D(2)O at 20 degrees C.

The value of in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging

The value of the combined in-phase (IP) and opposed-phase (OP) T1-weighted (T1-W) breath-hold FLASH sequences for hepatic imaging, especially for fat content, was evaluated. Non-contrast-enhanced IP and OP T1-W GRE breath-hold images were obtained in 76 patients refereed for abdominal MRI at 1.5T. 76 patients were divided into three groups for analysis: (1) liver without mass (n = 8); (2) liver with hepatoma (n = 34); (3) liver with haemangioma or cyst (n = 34). Liver/spleen and liver/lesion signal-to-noise (SNR) and contrast-to-noise ratio (CNR) were assessed for lesion detection. Images between IP and OP sequences were compared quantitatively. The results showed that there was not statistically significant difference in liver/spleen and liver/lesion SNR between IP and OP sequences. In the patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SNR than those of the IP sequences. Furthermore, OP imaging showed fatty infiltration in 14 cases and demonstrated hyperintense peritumor rim in 4 cases. In 14 cases of fatty infiltration, many lesions were identified using IP images. The use of IP and OP GRE sequences provides complementary diagnostic information for hepatic lesions and fat content. Focal hepatic lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.

[Expression of VEGF and tumor angiogenesis in bladder cancer]

OBJECTIVE

To evaluate expression of vascular endothelial growth factor (VEGF) and its relation to angiogenesis in bladder cancer.

METHODS

The expression of VEGF by immunohistochemical staining was examined in 68 cases of primary transitional carcinoma (TCC) and 7 subjects with normal urothelium. Microvessel density (MVD) in 40 cases of invasive bladder cancer was determined by Factor VIII immunohistochemical staining.

RESULTS

The expression of VEGF was negative or low level in all normal bladder tissue but high in bladder cancer. VEGF and MVD were closely related to tumor cell nuclear grade and clinical stage. The average MVD was higher in the cases with the high level expression of VEGF, than in those with the low level expression of VEGF.

CONCLUSIONS

This study indicates that VEGF is positively correlated with the occurrence and progression of bladder cancer. VEGF is one of the primary angiogenic factors for bladder cancer, and is able to induce tumor angiogenesis and accelerate tumor growth. Quantification of VEGF may provide a valuable marker for a poorer prognosis of patients.

Effect of integrin on procollagen synthesis by fibroblasts from scleroderma

OBJECTIVE

To investigate the effect of integrin on fibroblasts from scleroderma in the production of procollagen.

METHODS

Phosphorothioate modified antisense oligonucleotides were used to interfere with the expression of integrin alpha 5 or beta 1 subunit on fibroblasts from 10 cases of scleroderma, and then the changes of procollagen mRNA due to the decline in level of integrin were observed by using RT-PCR.

RESULTS

Expression of integrin alpha 5 or beta 1 subunit was specifically inhibited by their corresponding antisense oligonucleotides. Fibroblasts with decreased expression of alpha 5 or beta 1 subunit produced lower level of procollagen alpha 1 (I), alpha 1 (III) mRNA in comparison to the control.

CONCLUSION

Overproduction of procollagen may be inhibited at the level of transcription by lowering the expression of integrin alpha 5 or beta 1 subunit on fibroblasts in scleroderma.

Context-based lossless and near-lossless compression of EEG signals

In this paper, we study compression techniques for electroencephalograph (EEG) signals. A variety of lossless compression techniques, including compress, gzip, bzip, shorten, and several predictive coding methods, are investigated and compared. The methods range from simple dictionary-based approaches to more sophisticated context modeling techniques. It is seen that compression ratios obtained by lossless compression are limited even with sophisticated context-based bias cancellation and activity-based conditional coding. Though lossy compression can yield significantly higher compression ratios while potentially preserving diagnostic accuracy, it is not usually employed due to legal concerns. Hence, we investigate a near-lossless compression technique that gives quantitative bounds on the errors introduced during compression. It is observed that such a technique gives significantly higher compression ratios (up to 3-bit/sample saving with less than 1% error). Compression results are reported for EEG's recorded under various clinical conditions.

Adaptive estimation of latency change in evoked potentials by direct least mean p-norm time-delay estimation

Evoked potentials (EP) have been widely used to quantify neurological system properties. Changes in EP latency may indicate impending neurological injury. Traditional EP analyses are developed under the condition that the background noise in EP analysis are Gaussian distributed. This paper proposes a latency change detection and estimation algorithm under alpha-stable noise condition, a generalization of Gaussian noise assumption. An analysis shows that the alpha-stable model fits the noises found in the impact acceleration experiment under study better than the Gaussian model. The robustness of the proposed algorithm is demonstrated through computer simulations and experimental data analysis under both Gaussian and alpha-stable noise environments.