Prognostic significance of cyclin D1, β-catenin, and MTA1 in patients with invasive ductal carcinoma of the breast

BACKGROUND

To investigate markers for predicting breast cancer progression, we performed a candidate gene-based study that assessed expression change of three genes, cyclin D1, β-catenin, and metastasis-associated protein-1 (MTA1), involving in aggressive phenotypes of cancerous cells, namely hyperproliferation, epithelial-mesenchymal transition, and global transcriptional regulation.

METHODS

Specimens were from 150 enrolled female patients, with invasive ductal carcinoma, followed up for more than 10 years. mRNA expression of cyclin D1, β-catenin, and MTA1 in cancerous and noncancerous cells microdissected from the primary tumor site was determined by quantitative real-time PCR. The relationship between mRNA expression levels of the genes and clinicopathologic features was assessed by statistical analysis. Disease-free and overall survival (DFS and OS) were analyzed by Kaplan-Meier analysis with log-rank test and a multivariate Cox regression model.

RESULTS

Cyclin D1 was shown to be overexpressed in late-stage breast cancer (stage III/IV). Breast cancer with lymph node metastasis (LNM) showed significantly higher frequency of overexpressed cyclin D1, β-catenin, and MTA1 (P < 0.05). Patients carrying greater numbers of overexpressed genes had joint effects on increased risk in tumors of advanced stages (P ( trend ) = 0.03) and LNM (P ( trend ) < 0.01). In the LNM-negative group, patients whose tumors with greater number of cyclin D1, β-catenin, and MTA1 overexpressions were associated with poorer clinical outcomes, with hazard ratio of 14.79 for OS (P = 0.015) and 7.54 for DFS (P = 0.015) using multivariate Cox regression analysis during the 10-year follow-up.

CONCLUSIONS

Higher expression of cyclin D1, β-catenin, and MTA1 mRNAs in breast cancers may prove effective in predicting unfavorable outcomes of breast cancer.

Abstract 1094: MicroRNA-30a inhibits vimentin expression and as a prognostic marker in breast cancer

Recent studies have suggested a significant role of microRNAs (miRNAs) in the regulation of cancer development. This study examined whether they play a role in breast cancer progression.A miRNA microarray analysis was performed on laser-capture microdissected breast tumors of different lymph-node metastasis status showing different progression signatures, indicated by overexpression of cyclin D1 and β-catenin genes, to identify specific miRNAs that exhibit significant differences in expression. Functional interaction between the candidate miRNA (i.e. miR-30a) and the gene (i.e. Vim gene, coding for vimentin, a protein involved in epithelial-mesenchymal transition) possibly regulated by miR-30a was verified. We further examined whether decreased expression of miR-30a was associated with breast cancer progression.miR-30a negatively regulated vimentin expression, by binding to the 3′-untranslated region of Vim. Ectopic expression of miR-30a was found to suppress the migration and invasiveness phenotypes of breast cancer cell lines. More importantly, breast cancer patients with decreased miR-30a level in primary cancerous sites were found to be associated with poor clinical features (late tumor stage and lymph node metastasis) and worse progression, demonstrating an increased hazard ratio (HR) for recurrence or recurrence plus mortality during the follow-up period (P&lt;0.05). These findings provide a support of clinical importance of miR-30a in mediating breast tumor progression. Identification of miR-30a-mediated regulation of vimentin might provide a promising therapeutic target in treating breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1094. doi:1538-7445.AM2012-1094

Fabrication of pillared PLGA microvessel scaffold using femtosecond laser ablation

One of the persistent challenges confronting tissue engineering is the lack of intrinsic microvessels for the transportation of nutrients and metabolites. An artificial microvascular system could be a feasible solution to this problem. In this study, the femtosecond laser ablation technique was implemented for the fabrication of pillared microvessel scaffolds of polylactic-co-glycolic acid (PLGA). This novel scaffold facilitates implementation of the conventional cell seeding process. The progress of cell growth can be observed in vitro by optical microscopy. The problems of becoming milky or completely opaque with the conventional PLGA scaffold after cell seeding can be resolved. In this study, PLGA microvessel scaffolds consisting of 47 μm × 80 μm pillared branches were produced. Results of cell culturing of bovine endothelial cells demonstrate that the cells adhere well and grow to surround each branch of the proposed pillared microvessel networks.

MicroRNA-30a inhibits cell migration and invasion by downregulating vimentin expression and is a potential prognostic marker in breast cancer

Tumor recurrence and metastasis result in an unfavorable prognosis for cancer patients. Recent studies have suggested that specific microRNAs (miRNAs) may play important roles in the development of cancer cells. However, prognostic markers and the outcome prediction of the miRNA signature in breast cancer patients have not been comprehensively assessed. The aim of this study was to identify miRNA biomarkers relating to clinicopathological features and outcome of breast cancer. A miRNA microarray analysis was performed on breast tumors of different lymph node metastasis status and with different progression signatures, indicated by overexpression of cyclin D1 and β-catenin genes, to identify miRNAs showing a significant difference in expression. The functional interaction between the candidate miRNA, miR-30a, and the target gene, Vim, which codes for vimentin, a protein involved in epithelial-mesenchymal transition, was examined using the luciferase reporter assay, western blotting, and migration and invasion assays. The association between the decreased miR-30a levels and breast cancer progression was examined in a survival analysis. miR-30a negatively regulated vimentin expression by binding to the 3'-untranslated region of Vim. Overexpression of miR-30a suppressed the migration and invasiveness phenotypes of breast cancer cell lines. Moreover, reduced tumor expression of miR-30a in breast cancer patients was associated with an unfavorable outcome, including late tumor stage, lymph node metastasis, and worse progression (mortality and recurrence) (p < 0.05). In conclusion, these findings suggest a role for miR-30a in inhibiting breast tumor invasiveness and metastasis. The finding that miR-30a downmodulates vimentin expression might provide a therapeutic target for the treatment of breast cancer.

Polymorphisms of DNA repair pathway genes and cigarette smoking in relation to susceptibility to large artery atherosclerotic stroke among ethnic Chinese in Taiwan

AIM

Cigarette-smoking induced oxidative DNA damage to endothelial cells has been reported to play an etiological role in atherosclerosis development. Individual vulnerability to oxidative stress through smoking exposure and the ability to repair DNA damage, which plays a critical role in modifying the risk susceptibility of large artery atherosclerotic (LAA) stroke, is hypothesized. Thus, we examined the effect of genetic polymorphisms of DNA repair pathway genes and cigarette smoking in relation to risk susceptibility of LAA stroke.

METHODS

We enrolled 116 LAA stroke patients and 315 healthy controls from the Armed Forces Taoyuan General Hospital, Taoyuan, Taiwan. Genotyping of polymorphisms of the OGG1 (Ser326Cys), XRCC1 (Arg399Gln), ERCC2 (Lys751Gln), and ERCC5 (Asp1104His) genes was performed and used to evaluate LAA stroke susceptibility.

RESULTS

Of those non-synonymous polymorphisms, the ERCC2 Lys751Gln variant was found to be associated with LAA stroke risk (OR: 1.69, 95%CI: 1.02-2.86), and this association was more pronounced in smokers, manifesting a 2.73-fold increased risk of LAA stroke (p=0.027). A joint effect on risk elevation of LAA stroke was seen in those patients with OGG1 and ERCC2 polymorphisms (OR: 2.75, 95%CI: 1.26-6.00). Moreover, among smokers carrying the OGG1 Ser326Cys polymorphism, there was a tendency toward an increased risk of LAA stroke in those patients who had a greater number of high-risk genotypes of XRCC1, ERCC2, and ERCC5 polymorphisms (p(trend)=0.010).

CONCLUSION

The susceptible polymorphisms of DNA repair pathway genes may have a modifying effect on the elevated risk of LAA stroke in smokers among ethnic Chinese in Taiwan.

Characteristics of male fertility after renal transplantation

We investigated factors such as time span between transplantation and having offspring, the dosage of immunosuppressive agents during fertilisation and the effects of fertilisation on recipient's renal allograft function in 212 male recipients registered at eight Chinese organ transplantation centres. Our results are as follows: the 212 male renal allograft recipients conceived with their wives between 15 and 204 months after transplantation. The wives who became pregnant at 15-24 months after the renal transplantation gave birth to a total of 20 babies with an average weight of 3115 ± 517 g, of which 3 (15.0%) were premature. The wives who became pregnant at 25-204 months after the renal transplantation gave birth to a total of 196 babies with an average weight of 3384 ± 438 g, of which 6 (3.1%) were premature. All recipients had normal renal function during the fertile period. In conclusion, the fertility capacity of male renal allograft recipients was associated with the time after transplantation and the dose of immunosuppressive agents used during fertilisation. It might be helpful to have a fertility capacity evaluation before fertilisation. There were no effects of fertility on renal allograft function.

Association of MTHFR, MTR, and MTRR polymorphisms with Parkinson's disease among ethnic Chinese in Taiwan

BACKGROUND

Influence of folate/homocysteine conversion is considered to be important in the pathogenesis of Parkinson's disease (PD). However, association of the folate metabolic pathway gene polymorphisms with PD susceptibility remains unclear.

METHODS

To test this possibility in PD, we conducted a hospital-based case-control study constituting 211 patients and 218 age- and sex-matched controls of ethnic Chinese in Taiwan. Genotyping assay was performed to screen for polymorphisms of the methylenetetrahydrofolate reductase (MTHFR C677T), methyltetrahydrofolate-homocysteine methyltransferase (MTR A2756G), and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR A1049G and C1783T) genes and assess the association between these genotype polymorphisms and PD risk using logistic regression analysis.

RESULTS

Of these four non-synonymous polymorphisms, the MTRR 1049GG variant was significantly associated with PD susceptibility (OR=3.17, 95%CI=1.08-9.35). Furthermore, we stratified our patients based on the MTHFR 677TT genotype in different strata, a significant association between the joint effect of polymorphisms and PD risk was observed in those patients whose genotypes were MTRR A1049G/MTR A2756G or MTRR C1783T/MTR A2756G (P<0.05).

CONCLUSION

Our findings provide support for the synergistic effects of polymorphisms in the folate metabolic pathway genes in PD susceptibility; the increased PD risk would be more significant in carriers with the polymorphisms of MTHFR, MTR, and MTRR genes.

Abstract 1870: Genotype polymorphisms of DNA repair genes interact with estrogen exposure to breast cancer susceptibility

Endogenous estrogen is suggested to initiate cell proliferation and cause oxidative DNA damage during breast tumorigenesis. Cells eliminate DNA damages by repair enzymes. Genotypic variants of DNA damage repair genes, participating base excision repair (BER) and nucleotide excision repair (NER) pathways, may act as modifiers that affect the association between estrogen exposure and breast cancer. In a hospital-based case-control study of female breast cancer, DNA samples from 401 cases and 533 healthy controls were enrolled among Chinese women in Taiwan. Genotyping polymorphisms of XRCC1 (Arg194Trp and Arg399Gln), OGG1 (Ser326Cys and Arg229Gln), ERCC2 Lys751Gln, ERCC4 Pro662Ser, and ERCC5 His1104Asp were determined and used to evaluate breast cancer susceptibility. Of these non-synonymous polymorphisms, ERCC5 1104Asp variant was significantly associated with breast cancer (OR=1.42; 95%CI=1.08-1.97), and this was more pronounced in women with prolonged estrogen exposure. A trend toward an increased risk of developing breast cancer was observed in women who carried greater numbers of combined high-risk genotypes of BER and NER genes (Ptrend = 0.038). The synergistic effect of multiple genes on risk elevation was significant in women having a longer period of estrogen exposure (&gt;26 years), a longer menarche-to-FFTP interval (&gt;11 years), greater age at the first full-term pregnancy (&gt;26 years), and higher body mass index (&gt;22) (all P&lt;0.05). In conclusion, this study demonstrates that genotype polymorphisms for the DNA damage repair confer higher risk in individual susceptibility to endogenous estrogen on female breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1870.

A Comparative Study of Digital and Anatomical Techniques in Skull Base Measurement

This study compared the accuracy of measurements of the skull base made using computed tomography (CT) images and an image-guided surgery system with those made using scientific callipers in order to evaluate the practicability of replacing conventional direct anatomical measurements with digitized techniques in skull base surgery. Important bony landmarks and parameters were measured using the three different methods in 25 cadaver skull bases. No statistically significant differences were observed between the methods. Coefficient of variation calculations indicated that data obtained from CT images was the most stable. Digital methods of navigation have the potential to reflect individual skull base anatomical features more accurately than traditional group-based data, but it is important to assess their accuracy. This study demonstrated that CT imageology and image-guided surgery systems can provide accurate anatomical measurements. Digital methods are also more flexible and less variable, and may have wide applications in this field. Though not perfect, digital imaging is a promising tool for skull base surgery.

Polymorphism of cytosolic serine hydroxymethyltransferase, estrogen and breast cancer risk among Chinese women in Taiwan

Cytosolic serine hydroxymethyltransferase (cSHMT) is key to intersection of folate-metabolic pathway, participating in the pyrimidine synthesis for DNA repair. Based on the hypothesis that variants of the cSHMT C1420T together with methionine synthase (MS A2756G) and 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) are associated with breast cancer, we performed a multigenic case-control study of the effects to breast cancer risk of four polymorphisms of folate-metabolizing genes against duration of estrogen exposure. Support of our hypothesis came from the following observations: (i) Allelic frequency of cSHMT C1420T was higher in the controls than in the cases, manifesting a 0.56-fold risk reduction in breast cancer (95%CI = 0.39-0.80); and this association was more significant in those women are susceptible to time of estrogen exposure. (ii) A joint effect of the cSHMT and MS polymorphisms significantly reduced susceptibility to breast cancer (aOR = 0.55; 95%CI = 0.34-0.88). (iii) There was a trend toward a reduced risk of breast cancer in women carrying a greater number of putative low-risk genotypes (Ptrend = 0.048). (iv) This synergistic effects on risk reduction was significantly interacted with length of estrogen exposure, exhibiting a longer time of estrogen exposure (> or =30 years), menarche-to-FFTP interval (>11 years), age at the first full-term pregnancy (< or =25 years), and body mass index (< or =24). In conclusion, our study provides support to account for the preferential role of cSHMT polymorphism to lower risk of female breast cancer, and such reduced risk would be more significant in carriers with the polymorphisms of MS and MTHFR genes.

Increased expression of SRp40 affecting CD44 splicing is associated with the clinical outcome of lymph node metastasis in human breast cancer

BACKGROUND

During the malignant transformation of breast tissues, the pre-mRNA precursor splicing of specific genes can be flexibly regulated, leading to the formation of different forms or amounts of mRNA in response to the cellular microenvironment, and is frequently associated with cell tumorigenesis and may even cause tumor metastasis. Regulation of pre-mRNA splicing by serine-arginine (SR)-rich phosphoprotein is hypothesized to be associated with tumor cell metastasis.

METHODS

We enrolled 55 breast cancer patients (32 with lymph node metastasis; LNM) with paired tissue samples consisting of cancerous and tumor-adjacent normal portions and assayed these tissues for gene expression of the SR family using quantitative real-time RT-PCR (qRT-PCR), then evaluated an association with LNM of breast cancer. Furthermore, we examined whether increased expression of a specific SR gene was associated with the presence of specific CD44 spliced variants using qualitative reverse-transcription PCR (RT-PCR).

RESULTS

Support for our hypothesis came from the observations that breast tumor tissues displayed higher level of SRp40 expression as compared with the paired non-cancerous tissues, which manifested the significant association between increased SRp40 expression and LNM (OR=4.48, 95% CI, 1.08-19.50, P=0.018). In addition, the primary tumors of breast with increased expression of SRp40 gene were associated with the presence of the large CD44 inclusion variants, CD44v2, CD44v3, CD44v5, and CD44v6 (P<0.05).

CONCLUSION

Increased expression of SRp40 can be detected in breast tumor tissues with a high degree of sensitivity, and that higher expression of SRp40 closely correlates with alternative pre-mRNA splicing of CD44, which may serve as an earlier marker in predicting the risk to breast cancer patients of developing LNM.

Sle3 and Sle5 can independently couple with Sle1 to mediate severe lupus nephritis

Genetic analyses of the lupus-prone NZM2410 mouse have identified multiple susceptibility loci on chromosome 7, termed Sle3 and Sle5. Both of these loci were contained within a large congenic interval, originally termed as Sle3 that strongly impacts a variety of myeloid and T-cell phenotypes and mediates fatal lupus nephritis when combined with Sle1. We have now produced two subcongenic strains, B6.Sle3 and B6.Sle5, carrying the Sle3 and Sle5 intervals separately and characterized their phenotypes as monocongenic strains and individually in combination with Sle1. Neither B6.Sle3 nor B6.Sle5 monocongenic strain develop severe autoimmunity; however, both of these intervals cause the development of severe glomerulonephritis when combined with Sle1. Thus, B6.Sle1Sle3 and B6.Sle1Sle5 exhibit splenomegaly, expansion of activated B and CD4+ T-cell populations and high levels of IgG and IgM autoantibodies targeting multiple nuclear antigens, intact glomeruli and various other autoantigens. In addition, B6.Sle1Sle3 mice also produced higher levels of IgA antinuclear autoantibodies, which were implicated in the development of IgA nephropathy. Our results indicate that Sle3 and Sle5 can independently complement with Sle1, through shared and unique mechanisms, to mediate the development of severe autoimmunity.

Substituted amylose matrices for oral drug delivery

High amylose corn starch was used to obtain substituted amylose (SA) polymers by chemically modifying hydroxyl groups by an etherification process using 1,2-epoxypropanol. Tablets for drug-controlled release were prepared by direct compression and their release properties assessed by an in vitro dissolution test (USP XXIII no 2). The polymer swelling was characterized by measuring gravimetrically the water uptake ability of polymer tablets. SA hydrophilic matrix tablets present sequentially a burst effect, typical of hydrophilic matrices, and a near constant release, typical of reservoir systems. After the burst effect, surface pores disappear progressively by molecular association of amylose chains; this allows the creation of a polymer layer acting as a diffusion barrier and explains the peculiar behaviour of SA polymers. Several formulation parameters such as compression force, drug loading, tablet weight and insoluble diluent concentration were investigated. On the other hand, tablet thickness, scanning electron microscope analysis and mercury intrusion porosimetry showed that the high crushing strength values observed for SA tablets were due to an unusual melting process occurring during tabletting although the tablet external layer went only through densification, deformation and partial melting. In contrast, HPMC tablets did not show any traces of a melting process.

Relationships among acylation stimulating protein, adiponectin and complement C3 in lean vs obese type 2 diabetes

OBJECTIVE

The purpose of this study was to determine the relationships between adipocyte hormones acylation stimulating protein (ASP), adiponectin, complement C3 (C3) (ASP precursor) and insulin, C-reactive protein (CRP), lipid profiles and insulin resistance in lean vs obese type 2 diabetes subjects.

SUBJECTS

Lean type 2 diabetes subjects (DL n = 27) vs obese type 2 diabetes subjects (DO n = 55) were compared to age-matched nondiabetic groups (Obese, OB n = 55 and control, CTL n = 50).

RESULTS

The DO group demonstrated significant increases in plasma ASP and C3 with decreases in plasma adiponectin as compared to CTL. Interestingly, these increases in ASP and C3 were as high, or greater, in the DL group in spite of normal weight. By contrast adiponectin in the DL group was comparable to CTL, in spite of marked insulin resistance. C3 correlated with insulin, glucose and homeostasis model assessment of insulin resistance (HOMA-IR); ASP correlated with body mass index (BMI), glucose, insulin and plasma lipid parameters (non-esterified fatty acids (NEFA), triglyceride, cholesterol and apolipoprotein B). Adiponectin correlated with BMI, glucose, NEFA, triglyceride, high-density lipoprotein cholesterol and apolipoprotein A1 but not HOMA-IR, ASP or C3. CRP correlated only with HOMA-IR.

CONCLUSION

Increased ASP and C3 are both associated with diabetes and related lipid factors but are not regulated coordinately. Adiponectin appears to be more closely related to body size (decreased in obese subjects) than insulin resistance in these subjects.

Engineering and functional evaluation of a single-chain antibody against HIV-1 external glycoprotein gp120

The HIV-1 envelope glycoprotein surface subunit gp120 is an attractive target for molecular intervention. This is because anti-HIV-1 gp120 neutralizing antibodies display the potential ability to inhibit HIV-1 infection. The present investigation describes the construction of a genetically engineered single chain antibody (scFv102) against HIV-1 gp120, its expression and functional evaluation. The parental hybridoma cell line (102) produces an immunoglobulin directed against the conserved CD4-binding region of gp120. cDNAs encoding the variable regions of the heavy (V(H)) and light (V(L)) chains were prepared by reverse transcription PCR and linked together with an oligonucleotide encoding a linker peptide (Gly(4)Ser)(3) to produce a single chain antibody gene. The resulting DNA construct was cloned into a prokaryotic expression vector (pET28) and recombinant scFv102 was expressed in Eserichia coli as an insoluble protein. The denatured scFv102 was refolded and purified by immobilized metal ion affinity chromatography. Purified scFv102 had the same specificity as the intact IgG in immuno-blotting assays and immuno-fluorescence (IF) detection, but ELISA analyses demonstrated the affinity of scFv102 to be 5-fold lower than that of the parental monoclonal antibody. In neutralization assays, scFv102 at concentrations lower than 40 microg/ml exhibited efficient interference with viral replication and inhibition of viral infection (90%) across a range of primary isolates of subtype B HIV-1. These results suggest that the constructed anti-HIV-1 gp120 scFv102 has good biological activity and can potentially be used for in vitro diagnostic and in vivo therapeutic applications.

Topical 5-aminolaevulinic acid-photodynamic therapy for the treatment of urethral condylomata acuminata

BACKGROUND

Electrocoagulation and laser evaporation for urethral condylomata acuminata have high recurrence rates and can be associated with urethral malformations.

OBJECTIVES

To investigate the effect of photodynamic therapy (PDT) with topical 5-aminolaevulinic acid (ALA) on urethral condylomata acuminata and to examine the histological changes in lesions of condylomata acuminata after ALA-PDT.

METHODS

Patients with urethral condylomata (n = 164) were given topical ALA followed by intraurethral PDT through a cylindrical fibre. Patients included 11 individuals with 16 penile or vulval condylomatous lesions which were biopsied before or after treatment; the histological changes were then evaluated by light microscopy and electron microscopy.

RESULTS

The complete response rate was 95% and the recurrence rate was 5% after 6-24 months of follow-up. Light microscopy revealed keratinocytes in the middle and upper layers of the epidermis showing marked vacuolation and some necrocytosis 1 and 3 h after PDT. Necrosis in all layers of the epidermis was noted 5 h after PDT. Electron microscopy of keratinocytes revealed distinct ultrastructural abnormalities of mitochondria and the endoplasmic reticulum, and membrane damage. Apoptotic bodies were detected 3 h after PDT and a large number of keratinocytes exhibited necrosis 5 h after PDT.

CONCLUSIONS

Results suggest that, compared with conventional therapies, topical ALA-PDT is a simple, effective, safe and well-tolerated treatment for urethral condylomata acuminata that is associated with a low recurrence rate. The mechanism might be the triggering of both apoptosis and necrosis by ALA-PDT in human papillomavirus-infected keratinocytes.

Correlation between voice handicap index and voice laboratory measurements in dysphonic patients

Factors underlying voice disorders can be categorized into three distinct domains: emotional, physical, and functional. The Voice Handicap Index (VHI) subjectively evaluates voice disorders in terms of these three factors. On the other hand, Voice Laboratory Measurements (VLM) use objective criteria to evaluate the severity of voice disorders. Use of these two different tests (VHI and VLM) on dysphonic patients has, however, tended to yield results that vary widely in their conclusions. This report reviewed 135 testing sessions on dysphonia patients. Seventy-nine of the tests were VHI, and 56 were VLM. All VHI and VLM parameters were entered into a statistical program and analyzed using a Pearson correlation. The results show that each VHI parameter provides a significant level of reliability (P < 0.01) when compared with other VHI parameters. Four VLM parameters also demonstrated significant reliability (P < 0.01) in comparison with other VLM parameters. However, when comparing across testing methods, VHI and VLM parameter reliability is shown to be poor (P > 0.05). With such a large discrepancy between the results of VHI and VLM testing, no objective parameter can yet be regarded as a definitive prognostic factor in a subjective evaluation of dysphonic patients.

Dissociation and subunit rearrangement of membrane-bound human C-reactive proteins

As one of the most important acute-phase reactants in human serum, C-reactive protein plays its physiological roles mainly on membranes. Here we show that the human C-reactive protein is two-dimensionally crystallized upon specific adsorption on the phosphorylcholine ligand containing membranes by monolayer approach. The 2.0-nm resolution projection structure of the two-dimensional crystals analyzed by electron microscopy and image reconstruction reveals open-ring-like pentamers in the crystals. The electron microscope graphs also show that the dissociated pentamers with open-ring-like structure occur in a closed packing region (not two-dimensionally crystallized). These results indicate a membrane-induced dissociation and rearrangement of hCRP, which may relate to the variety of hCRP's physiological functions.

Induction of cytochromes P450 1A1 and 1B1 by emodin in human lung adenocarcinoma cell line CL5

Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) is an active compound of many laxative herbal drugs. The present study aimed to determine the effects of emodin on cytochrome P450 (P450)-dependent monooxygenases of human lung adenocarcinoma CL5 cells. Treatment of CL5 cells with 100 microM emodin for 24 h induced benzo[a]pyrene hydroxylation, 7-ethoxyresorufin O-deethylation, and 7-ethoxycoumarin O-deethylation activities of S9 fractions. Immunoblot analysis of CL5 S9 proteins revealed that emodin induced proteins immunorelated to P450s 1A1 and 1B1. Northern blot analysis of total cellular RNA showed that emodin induced P450s 1A1 and 1B1 mRNA levels in CL5 cells. These inductive effects on P450 monooxygenase activity, protein, and mRNA were concentration- and time-dependent. Addition of emodin to CL5 cell microM S9 inhibited its 7-ethoxycoumarin O-deethylation activity. Treatment of CL5 cells with 10 microM 3-methylcholanthrene for 24 h induced monooxygenase activity and P450s 1A1 and 1B1 proteins and mRNA levels. Treatment of the lung cells with 100 microM emodin or purpurin (1,2,4-trihydroxyanthraquinone) for 24 h produced greater induction of P450s 1A1 and 1B1 mRNA than did anthraflavic acid (2,6-dihydroxyanthraquinone) or anthraquinone. The emodin treatment induced P450s 1A1 and 1B1 mRNA in human lung carcinoma NCI-H322 and breast cancer MCF-7 cells. Emodin induced P450 1A1, but not 1B1, mRNA in human hepatoma HepG2 cells. The present study demonstrates that emodin is an inducer of P450s 1A1 and 1B1 protein and mRNA in human lung adenocarcinoma CL5 cells. Modulation of P450 by emodin may be an important factor affecting metabolism and toxicity of the hydroxyanthraquinone in humans.

[Insect juvenile hormone enhancing gene expression in silkworm baculovirus vector system]

5th instar silkworms were infected with recombinant baculovirus containing phytase gene or wild type BmNPV at 48 hr after ecdysis, then treated with 100 ppm Juvenile hormone. It showed that the expression level of phytase gene and polyhedrin gene per silkworm was increased by 30% and 40%, respectively. The LT50 was lengthened for more than 4 h, and the average weight of sick silkworm was increased by 10%. The results indicated that the improvement of expression efficiency of phytase gene and polyhedrin gene was mainly caused by longer time of virus replication in silkworm after the treatment of Juvenile hormone.

[Separation of two isomers in the products of condensation reaction with trimethoxybenzaldehyde as raw material and quick determination of the concentration of its intermediates by high performance liquid chromatography]

The content ratio of the two isomers in the products of condensation reaction with trimethoxybenzaldehyde as raw material is the key factor to improve the productivity of trimethoprim(TMP). A quantitative method using Nova-Pak C18 column (3.9 mm i.d. x 150 mm, 4 microns) and tetrahydrofuran(THF)-water (30:70, V/V) as mobile phase with flow rate of 1.0 mL/min and UV 320 nm detector was established. A good linearity was obtained in the concentration range of 0.01 mg.L-1-10 mg.L-1. The detectable limits of trimethoxybenzaldehyde and alpha-(3,4,5-trimethoxy-benzal)-beta-methoxy-propionitrile were 2.0 micrograms/L and 1.0 microgram/L respectively. The method has been used to analyze real samples with satisfactory results.

Gene therapy attenuates the elevated blood pressure and glucose intolerance in an insulin-resistant model of hypertension

OBJECTIVE

Fructose feeding in male Sprague-Dawley (SD) rats results in a mild hypertension and glucose intolerance. Although the mechanism of this glucose intolerance and hypertension is not completely understood, a role for the renin-angiotensin system (RAS) has been proposed. In the current study our aim was to test the hypothesis that intervention of the RAS with a gene therapy approach would be effective in preventing the development of hypertension and glucose intolerance in this animal model.

DESIGN AND METHODS

Five-day-old SD rats were administered either an empty retroviral vector (LNSV) or retroviral vector containing AT1 receptor antisense DNA (AT1R-AS). The virus (25 microl, 8 x 10(9) CFU/ml) was injected into the heart and the animals were returned to their mothers. After weaning, half the animals from each group were placed on breeder's chow or a 60% fructose diet. Indirect blood pressures (BP) were determined and an oral glucose tolerance test (OGTT) was performed when the animals had been on the respective diets for 2 months.

RESULTS

Fructose-fed animals developed mild hypertension (145 +/- 3 versus 132 +/- 4 mmHg) by 6 weeks of dietary intervention. This increase in BP was prevented by AT1R-AS treatment (125 +/- 3 mmHg). At 2 months of age, fasting blood glucose was comparable among the four groups; however, the glucose excursion during the OGTT was significantly greater and more prolonged in the LNSV-treated, fructose-fed group than the other three groups. AT1R-AS treatment significantly prevented glucose intolerance in the fructose rat to levels observed in the controls.

CONCLUSIONS

Early fructose dietary treatment results in moderate hypertension and glucose intolerance, which is prevented by a single neonatal treatment with AT1R-AS. These results suggest that the RAS is involved in the glucose intolerance associated with fructose feeding and that genetic intervention is effective in this rat model.

Two-dimensional assembly of pentameric rabbit C-reactive proteins on lipid monolayers

The problem of pentamer packing on a two-dimensional plane is of concern not only in physics and mathematics but also in biology. The packing styles of pentamers may either be related to or reflect the physiological or biochemical properties of biological macromolecules. C-reactive protein (CRP), one of the classical members of the petraxin family, was recently two-dimensionally (2D) crystallized by us on lipid monolayers by specific adsorption (Wang, H. W., and Sui, S. F., 1999, J. Struct. Biol. 127, 283-286). Another type of the protein's 2D crystal under the same conditions was obtained in the present work. The new 2D crystal was studied using electron microscopy of negatively stained specimens followed by image processing. A projection map at 2.2-nm resolution was obtained. The previous 2D crystal (PI) and the current 2D crystal (PII) show different pentamer-packing styles. Both of them are closely related to the fivefold symmetry of the molecule itself. The coexistence and the spatial contiguity of the two types of pentamer assembly were observed in a visual field. The fivefold symmetrical macromolecule can form a pentiling pattern on a two-dimensional plane, which has never been reported in biological system before. The possible mechanism of the two-dimensional assembly of pentameric CRP on lipid monolayers is discussed.

[Effect of ATXII on opening modes of myocyte sodium channel, action potential and QT intervals of ECG]

Single sodium channel currents were recorded by patch clamp technique in isolated guinea-pig ventricular myocytes, and action potentials of papillary muscle and ECG were conventionally measured. Sea anemone toxin (ATXII), a high affinity toxin to sodium channel, was used to change the sodium channel dynamics. Changes in the duration of action potentials and the QT interval of ECG depending on the channel modes were studied in order to provide hints to an understanding of pathogenesis of the long QT syndrome (a genetic disease). With the binding of ATXII to the sodium channel, the occurrence frequency and the open time constant of the "long opening" mode of single Na channels increased significantly, whereas the action potential durations, APD50 and APD90, were prolonged by 23% and 27% respectively. Following application of ATXII, on the other hand, the QT interval and the QTc, a rectified QT interval, increased by 18.6% and 18.9% respectively. The results suggest that the dynamics or modes of Na channel play an important role in determining the action potential duration and the QT interval of ECG. The dynamical changes in Na channels induced by genetic mutation may be partially responsible for the long QT syndrome.

Immunolocalization of inducible nitric oxide synthase and 3-nitrotyrosine in the nasal mucosa of patients with rhinitis

Since nitric oxide (NO) can be involved in multiple physiological and pathological functions, we evaluated its possible involvement and that of peroxynitrite in the pathogenesis of rhinitis. Inferior nasal turbinates were obtained from allergic rhinitis and nonallergic rhinitis patients during corrective nasal surgery. The expressions of the inducible form of nitric oxide synthase (iNOS) and the production of peroxynitrite and its metabolite 3-nitrotyrosine were examined by immunohistochemistry in consecutive tissue sections. Each section (or tissue compartment) was given a score of 0-4 according to the labeling intensity seen, with the highest number representing the highest labeling intensity. The results showed that iNOS expression was present mainly in the mucosal epithelium, vascular endothelium, and submucosal glands. A significant difference was only observed in the labeling scores of glandular tissues of the allergic group, which had a higher iNOS labeling score. We also found that sections with a higher iNOS level did not necessarily exhibit a higher 3-nitrotyrosine labeling intensity. These data suggest that iNOS-derived NO may have a role in the pathophysiology of rhinitis, especially the glandular function of allergic nasal mucosa. Moreover, our findings suggest that the production of peroxynitrite in rhinitis patients is not dependent on the level of iNOS alone.

[Dynamic pre-concentration method of gas sample]

By utilizing the combination of frontal chromatography at ambient temperature, back-flushing and temperature gradient thermal desorption, a prototype of a dynamic pre-concentration system has been designed and evaluated. It realized the enrichment for gas samples of boiling point higher than - 103 degrees C without cryogenic facilities. To reduce the sample volume and enhance enrichment factor, the technique of momentarily non-steady state produced at the beginning of back-flushing, and the negative temperature gradient generated during thermal desorption were utilized, resulting a very sharp desorption band. Standard samples were tested to demonstrate the applicability of the method. At 10 mL sample volume, the enrichment factor was 100.

Performance of triple ditch: effects of duration and periodic operation programs

The periodic variation of operation states in triple ditch (BIO-DENITRO process) was investigated in a pilot-scale and a full-scale triple ditch treating raw wastewater containing 70% petrochemical wastewater and 30% domestic wastewater. Mathematical models describing the periodic variation of activated sludge concentrations in each ditch were proposed based on theoretical analysis and were verified in the pilot-scale and full-scale triple ditches respectively. The existence of optimal cycle time and time arrangement of periodic operation programs were demonstrated and discussed according to the mathematical models and the experimental results of the pilot-scale triple ditch operated in four different stages. Four rulers determining the duration and operation programs are suggested.

Attenuation of hypertension by systemic delivery of retroviral vector containing type I angiotensin II receptor antisense cDNA

Despite recent strides in the traditional pharmacological therapies in the control and management of hypertension, a successful prevention and cure for this disease by conventional drug strategy remain at a standstill. We have begun to investigate the conceptual possibility of the use of gene therapy in the control of hypertension. In this article we describe an experimental protocol that provides proof of the principle that antisense (AS) inhibition of Type I angiotensin II receptor (AT(1)-R) could prevent development of hypertension on a long-term basis. A retrovirus-based vector has been used to deliver AT(1)R-AS with high efficiency that attenuates development of high blood pressure and hypertension-associated cardiac and vascular pathophysiology in the spontaneously hypertensive rat.

Orthostatic hypotension in aging humans

We tested the hypothesis that hypotension occurred in older adults at the onset of orthostatic challenge as a result of vagal dysfunction. Responses of heart rate (HR) and mean arterial pressure (MAP) were compared between 10 healthy older and younger adults during onset and sustained lower body negative pressure (LBNP). A younger group was also assessed after blockade of the parasympathetic nervous system with the use of atropine or glycopyrrolate and after blockade of the beta(1)-adrenoceptor by use of metoprolol. Baseline HR (older vs. younger: 59 +/- 4 vs. 54 +/- 1 beats/min) and MAP (83 +/- 2 vs. 89 +/- 3 mmHg) were not significantly different between the groups. During -40 Torr, significant tachycardia occurred at the first HR response in the younger subjects without hypotension, whereas significant hypotension [change in MAP (DeltaMAP) -7 +/- 2 mmHg] was observed in the elderly without tachycardia. After the parasympathetic blockade, tachycardiac responses of younger subjects were diminished and associated with a significant hypotension at the onset of LBNP. However, MAP was not affected after the cardiac sympathetic blockade. We concluded that the elderly experienced orthostatic hypotension at the onset of orthostatic challenge because of a diminished HR response. However, an augmented vasoconstriction helped with the maintenance of their blood pressure during sustained LBNP.

Distinct ion channel classes are expressed on the outer nuclear envelope of T- and B-lymphocyte cell lines

The outer nuclear membrane, endoplasmic reticulum, and mitochondrial membrane ion channels are poorly understood, although they are important in the control of compartmental calcium levels, cell division, and apoptosis. Few direct recordings of these ion channels have been made because of the difficulty of accessing these intracellular membranes. Using patch-clamp techniques on isolated nuclei, we measured distinct ion channel classes on the outer nuclear envelope of T-cell (human Jurkat) and BFL5 cell (murine promyelocyte) lines. We first imaged the nuclear envelopes of both Jurkat and FL5 cells with atomic force microscopy to determine the density of pore proteins. The nuclear pore complex was intact at roughly similar densities in both cell types. In patch-clamp recordings of Jurkat nuclear membranes, Cl channels (105 +/- 5 pS) predominated and inactivated with negative pipette potentials. Nucleotides transiently inhibited the anion channel. In contrast, FL5 nuclear channels were cation selective (52 +/- 2 pS), were inactivated with positive membrane potentials, and were insensitive to GTPgammaS applied to the bath. We hypothesize that T- and B-cell nuclear membrane channels are distinct, and that this is perhaps related to their unique roles in the immune system.

Zebrafish ftz-f1 gene has two promoters, is alternatively spliced, and is expressed in digestive organs

Fushi-tarazu Factor-1 (FTZ-F1) is a family of nuclear receptors involved in various developmental processes. We have cloned a zebrafish FTZ-F1 gene, termed ff1, which belongs to the fetoprotein transcription factor/liver receptor homologue-1 (FTF/LRH-1) subgroup of the FTZ-F1 family. Four transcripts arise as a result of differential promoter usage and alternative splicing at the 3'-most exons. The longer transcript, form A, encodes a transcriptional activator. The shorter transcript, form B, lacks the activation domain, and hence could not activate transcription. The difference in promoter usage generates FF1 proteins with different N-terminal sequences. All four transcripts appear to be expressed in most of the adult tissues, whereas, during embryo development, the IIA form is the predominant transcript. Reverse transcriptase-PCR and in situ hybridization experiments showed that the ff1 transcript is expressed in the hypothalamus, spinal cord, mandibular arch and digestive organs, including pancreas, liver, and intestine. The expression of ff1 in the digestive organs implies its function in gut development.

Induction of cytochrome P-450 1A1 in human hepatoma HepG2 and lung carcinoma NCI-H322 cells by motorcycle exhaust particulate

The effects of motorcycle exhaust particulate (MEP) on human cytochrome P-450 (P-450)-dependent monooxygenases were determined using human hepatoma cell line HepG2 and lung carcinoma cell line NCI-H322 treated with organic extracts of MEP from a two-stroke engine. Gas chromatography and mass spectrometry analysis of MEP extract revealed the presence of carcinogens benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, chrysene, and indeno[1,2,3-c,d]pyrene in the chemical mixture. Treatment with MEP extract produced concentration- and time-dependent increases of monooxygenase activity in HepG2 cells. Treatment of the cells with 100 microg/ ml MEP extract for 24 h markedly increased benzo[a]pyrene hydroxylation, 7-ethoxycoumarin, and 7-ethoxyresorufin O-deethylation activities in microsomes. Immunoblot analysis of microsomal proteins using mouse monoclonal antibody 1-12-3 against P-450 1A1 revealed that MEP extract induced a P-450-immunorelated protein in the hepatoma cells. RNA blot analysis of cellular total RNA using a human P-450 1A1 3'-end cDNA probe showed that MEP extract increased the level of a hybridizable P-450 mRNA. These P-450 1A1 inductive effects of MEP extract were similar to those from treatment with 10 microM benzo[a]pyrene or 3-methylcholanthrene (3-MC) in HepG2 cells. Treatment of lung carcinoma NCI-H322 cells with 100 microg/ml MEP extract, 10 microM benzo[a]pyrene, or 3-MC resulted in induction of monooxygenase activity, protein, and mRNA of P-450 1A1, similar to the induction observed with the hepatoma cells. The present study demonstrates that MEP extract has the ability to induce human hepatic and pulmonary P-450 1A1 in the liver- and lung-derived cell lines, and the induction involves a pretranslational mechanism. Induction of the human hepatic and pulmonary P-450 1A1 in vitro may provide important information in the assessment of MEP metabolism and toxicity in humans.

Computerized rotational vestibular testing in normal subjects

BACKGROUND

As an integral part of the contemporary vestibular testing battery, computerized vestibular rotational testing provides physiologic stimuli and quantitative evaluation of the vestibulo-ocular reflex function of the horizontal semicircular canals. Clinically, it is most commonly used in the sinusoidal harmonic acceleration test (SHAT) and velocity step test. Because the results for a given subject may vary when tested using different facilities, the purpose of this study is to establish the normative data for our laboratory.

METHODS

Fifty-six normal subjects underwent the SHAT and velocity step test. Three parameters of SHAT--gain, phase and symmetry--were measured and recorded at 0.02, 0.05, 0.09 and 0.10 Hz. In the velocity step test, the three parameters of postrotatory nystagmus-time constant, maximum slow component eye velocity and directional preponderance were measured and recorded.

RESULTS

The means +/- standard deviations of gain in the SHAT were 0.47 +/- 0.16 at 0.02 Hz, 0.50 +/- 0.16 at 0.05 Hz, 0.50 +/- 0.16 at 0.09 Hz and 0.53 +/- 0.17 at 0.10 Hz. The coefficient of variation for SHAT gain was 0.32. The time constant means and standard deviations in the velocity step test were 13.44 +/- 3.53 and 13.52 +/- 3.69 for clockwise and counterclockwise rotations, respectively.

CONCLUSIONS

We conclude that computerized rotational vestibular testing is precise.

Quantitative analysis of Pc 4 localization in mouse lymphoma (LY-R) cells via double-label confocal fluorescence microscopy

Photodynamic therapy (PDT) is a novel cancer therapy that uses light-activated drugs (photosensitizers) to destroy tumor tissue. Reactive oxygen species produced during PDT are thought to cause the destruction of tumor tissue. However, the precise mechanism of PDT is not completely understood. To provide insight into the in vitro mechanisms of PDT, we studied the subcellular localization of the photosensitizer HOSiPcOSi(CH3)2-(CH2)3N(CH3)2 (Pc 4) in mouse lymphoma (LY-R) cells using double-label confocal fluorescence microscopy. This technique allowed us to observe the relative distributions of Pc 4 and an organelle-specific dye within the same cell via two, spectrally distinct, fluorescence images. To quantify the localization of Pc 4 within different organelles, linear correlation coefficients from the fluorescence data of Pc 4 and the organelle-specific dyes were calculated. Using this measurement, the subcellular spatial distributions of Pc 4 could be successfully monitored over an 18 h period. At early times (0-1 h) after introduction of Pc 4 to LY-R cells, the dye was found in the mitochondria, lysosomes and Golgi apparatus, as well as other cytoplasmic membranes, but not in the plasma membrane or the nucleus. Over the next 2 h, there was some loss of Pc 4 from the lysosomes as shown by the correlation coefficients. After an additional incubation period of 2 h Pc 4 slowly increased its accumulation in the lysosomes. The highest correlation coefficient (0.65) was for Pc 4 and BODIPY-FL C5 ceramide, which targets the Golgi apparatus, and also binds to other cytoplasmic membranes. The correlation coefficient was also high (0.60) for Pc 4 and a mitochondria-targeting dye (Mitotracker Green FM). Both of these correlation coefficients were higher than that for Pc 4 with the lysosome-targeting dye (Lysotracker Green DND-26). The results suggest that Pc 4 binds preferentially and strongly to mitochondria and Golgi complexes.

Transcriptional repression of p21((Waf1/Cip1/Sdi1)) gene by c-jun through Sp1 site

Previously, we found that c-jun represses the tumor suppressor p21((Waf1/Cip1/Sdi1)) (p21) gene expression. In this study, we further investigated the mechanism of the inhibitory effect of c-jun on p21. After analysis of a series of deletion and point mutants of p21 promoter, we found that Sp1-3 site (-77 and -83) relative to the transcription start site played an important role for c-jun-repressing-responsive element in the p21 promoter. Both Sp1 and Sp3 transcription factors were the key factors for this event. However, the data from electrophoretic mobility shift assay indicated that c-jun did not change the Sp1 DNA-binding affinity, suggesting that additional factors may be involved in the repression of p21 by c-jun. Furthermore, c-jun could inhibit butyrate-inducing p21 gene expression through Sp1, indicating at least one common pathway whereby p21 expression is affected by c-jun and butyrate in opposing actions. Moreover, the hyperphosphorylated retinoblastoma protein (Rb) increased in c-jun expressing cells, indicating that phosphorylated Rb may play a role in regulating Sp1 to repress p21 expression. This is the first demonstration of how housekeeping factors and oncogene product counteract the function of tumor suppressor genes to control cell cycle progression.

Trimeric ring-like structure of ArsA ATPase

ArsA protein is the soluble subunit of the Ars anion pump in the Escherichia coli membrane which extrudes arsenite or antimonite from the cytoplasm. The molecular weight of the subunit is 63 kDa. In the cell it hydrolyzes ATP, and the energy released is used by the membrane-bound subunit ArsB to transport the substrates across the membrane. We have obtained two-dimensional crystals of ArsA in the presence of arsenite on negatively-charged lipid monolayer composed of DMPS and DOPC. These crystals have been studied using electron microscopy of negatively-stained specimens followed by image processing. The projection map obtained at 2.4 nm resolution reveals a ring-like structure with threefold symmetry. Many molecular assemblies with the same ring-shape and dimensions were also seen dispersed on electron microscopy grids, prepared directly from purified ArsA protein solution. Size-exclusion chromatography of the protein sample with arsenite present revealed that the majority of the protein particles in solution have a molecular weight of about 180 kDa. Based on these experiments, we conclude that in solution the ArsA ATPase with substrate bound is mainly in a trimeric form.

[Expression and characterization of HIV-1 Gag p17-p24 protein]

The biological and immunological characteristics of HIV-1 core protein p17-24 expressed by recombinant vaccinia viruses were studied. The results of indirect immunofluorescence assay (I-IFA), Western blot and dot ELISA showed that the two recombinants could express the p24 gag and p17-24 gag fusion proteins in infected cell lines respectively. The electromicroscope observation revealed that the expressed proteins could also assemble into virus-like particles. The recombinant vaccinia viruses can also stimulate mice for the formation of anti HIV-1 Gag p24 antibody. When infected with the recombinant viruses, the chromosome DNA ladder caused by the apoptosis of the BHK cell was observed.

The multiple roles of conserved arginine 286 of 1-aminocyclopropane-1-carboxylate synthase. Coenzyme binding, substrate binding, and beyond

A pyridoxal 5'-phosphate (PLP)-dependent enzyme, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (S-adenosyl-L-Met methylthioadenosine-lyase, EC 4.4.1.14), catalyzes the conversion of S-adenosyl-L-methionine (AdoMet) to ACC. A tomato ACC synthase isozyme (LE-ACS2) with a deletion of 46 amino acids at the C terminus was chosen as the control enzyme for the study of the function of R286 in ACC synthase. R286 of the tomato ACC synthase was mutated to a leucine via site-directed mutagenesis. The ACC synthase mutant R286L was purified using a simplified two-step purification protocol. Circular dichroism (CD) analysis indicated that the overall three-dimensional structure of the mutant was indistinguishable from that of the control enzyme. Fluorescence spectroscopy revealed that the binding affinity of R286L ACC synthase for its cofactor PLP was reduced 20- to 25-fold compared with control. Kinetic analysis of R286L showed that this mutant ACC synthase had a significantly reduced turnover number (k(cat)) of 8.2 x 10(-3) s(-1) and an increased K(m) of 730 microM for AdoMet, leading to an 8,000-fold decrease in overall catalytic efficiency compared with the control enzyme. Thus, R286 of tomato ACC synthase is involved in binding both PLP and AdoMet.

Quantitative laser scanning confocal autofluorescence microscopy of normal, premalignant, and malignant colonic tissues

Laser scanning confocal autofluorescence microscopy (LSCAM) using 351- to 364-nm excitation light was used to quantitatively compare fluorescent spectral emission of unstained, frozen histological sections of normal, premalignant, and malignant colonic tissues. To identify the spatial origins of fluorescent signals accurately, the same frozen section slides used for microscopy were fixed and histochemically stained immediately following LSCAM imaging. Tissue fluorescence emission was quantified in terms of the intrinsic fluorescence coefficient beta (lambda), defined as the fluorescence power per unit tissue volume per unit wavelength (centered at lambda) divided by the incident light irradiance. Over all emission wavelengths, colonic tissues emitted autofluorescence ranging from beta (lambda) approximately 10(-1.5) to 10(-3.0) cm-1. In the 530- to 610-nm spectral region, markedly increased autofluorescence (beta up to 10(-2.5)) was observed in the dysplastic cells of adenomatous polyps, as compared to normal epithelial cells. Compared to adenomatous polyps, decreased dysplastic cell autofluorescence was observed in adenocarcinoma. The brightest fluorescence in the lamina propria, which was attributed to eosinophils (beta approximately 10(-2.5)) in previous studies, was also observed in other granular structures (beta up to 10(-1.4)). LSCAM reveals quantitative significant differences in fluorescence emission between normal and diseased colonic tissues.

Pentameric two-dimensional crystallization of rabbit C-reactive protein on lipid monolayers

As a member of the pentraxin family, C-reactive protein plays various roles in the nonspecific immunity of animals. Though soluble, C-reactive protein always functions on membranes. In order to study the structure of the membrane-bound protein and the reaction between protein and membranes, two-dimensional (2D) crystallization of rabbit C-reactive protein on lipid monolayers was performed. The 2D crystals composed of pentameric proteins were obtained on lipid monolayers by specific adsorption for the first time. The projection map at 26-A resolution is presented, which exhibits P2 symmetry with lattice parameters a = 158(+/-3) A, b = 92(+/-1) A, and gamma = 107(+/-1) degrees. The current work may give a basis for the further study on the structure of complexes made up of C-reactive protein with its functional binding molecules on membranes.

The nature of the catalytic domain of 2'-5'-oligoadenylate synthetases

2'-5'-Oligoadenylate (2-5(A)) synthetases are a family of interferon-induced enzymes that are activated by double-stranded RNA. To understand why, unlike other DNA and RNA polymerases, they catalyze 2'-5' instead of 3'-5' phosphodiester bond formation, we used molecular modeling to compare the structure of the catalytic domain of DNA polymerase beta (pol beta) to that of a region of the P69 isozyme of 2-5(A) synthetase. Although the primary sequence identity is low, like pol beta, P69 can assume an alphabetabetaalphabetabetabeta structure in this region. Moreover, mutation of the three Asp residues of P69, which correspond to the three catalytic site Asp residues of pol beta, inactivated the enzyme without affecting its substrate and activator binding capacity, providing further credence to the concept that this region is the catalytic domain of P69. This domain is highly conserved among all 2-5(A) synthetase isozymes. Biochemical and mutational studies demonstrated that dimerization of the P69 protein is required for its enzyme activity. However, a dimer containing a wild type subunit and an inactive catalytic domain mutant subunit was also active. The rate of catalysis of the heterodimer was half of that of the wild type homodimer, although the two proteins bound double-stranded RNA and ATP equally well.

Reversal of hypertension by angiotensin II type 1 receptor antisense gene therapy in the adult SHR

Pharmacological blockade of the renin-angiotensin system in both hypertensive patients and animal models such as the spontaneously hypertensive rat (SHR) effectively reduces blood pressure (BP). Recent studies have established that virally mediated delivery (vector LNSV) of antisense to the angiotensin II type 1 receptor (LNSV-AT1R-AS) will attenuate or abolish the development of hypertension in the SHR. However, the effectiveness of this gene therapy approach to reduce high BP once it is established in the adult has not been ascertained. In this study, we investigated the hypothesis that viral delivery of AT1R-AS into the adult SHR will reduce BP and reverse the vascular reactivity associated with the hypertension. Intracardiac injection of virus particles containing LNSV-AT1R-AS into adult SHR resulted in a 30- to 60-mmHg reduction in BP that was maintained for up to 36 days compared with SHR treated with virus alone (LNSV without antisense). Measurement of renal resistance arteriolar reactivity demonstrated a leftward shift in the KCl and phenylephrine concentration-response relationships and an impaired endothelium-dependent relaxation to ACh in LNSV-treated SHR compared with control Wistar-Kyoto rats. These vascular alterations were reversed in the LNSV-AT1R-AS-treated SHR. Collectively, these data demonstrate that virally mediated gene delivery of AT1R-AS can effectively reduce BP and reverse renovascular pathophysiology associated with the hypertensive state when administered to the adult SHR.

Mitochondrial depolarization accompanies cytochrome c release during apoptosis in PC6 cells

Cytochrome c is released from mitochondria into the cytosol in cells undergoing apoptosis. The temporal relationship between cytochrome c release and loss of mitochondrial membrane potential was monitored by laser-scanning confocal microscopy in single living pheochromocytoma-6 cells undergoing apoptosis induced by staurosporine. Mitochondrial membrane potential monitored by tetramethylrhodamine methyl ester decreased abruptly in individual cells from 2 to 7 h after treatment with staurosporine. Depolarization was accompanied by cytochrome c release documented by release of transfected green fluorescent protein-tagged cytochrome c in these cells. The results show that mitochondrial depolarization accompanies cytochrome c release in pheochromocytoma-6 cells undergoing apoptosis.

Regulation of T lymphocyte trafficking into lymph nodes during an immune response by the chemokines macrophage inflammatory protein (MIP)-1 alpha and MIP-1 beta

By virtue of their target cell specificity, chemokines have the potential to selectively recruit leukocyte subpopulations into sites of inflammation. Their role in regulation of T lymphocyte traffic into lymph nodes during the development of an immune response has not previously been explored. The sensitization phase of contact hypersensitivity induced by the hapten, dinitrofluorobenzene (DNFB) in the mouse was used as a model of T lymphocyte trafficking in response to antigenic stimulation. Rapid accumulation of CD8+ and CD4+ T cells in the draining lymph nodes was closely associated with strongly enhanced expression of macrophage inflammatory protein (MIP)-1 alpha and MIP-1 beta mRNAs and proteins. Mast cells accumulating in the nodes during DNFB sensitization were the predominant source of MIP-1 beta, whereas MIP-1 alpha was expressed by multiple cell types. Neutralization of these chemokines profoundly inhibited T lymphocyte trafficking into lymph nodes and altered the outcome of a subsequent challenge to DNFB. Thus, beta-chemokines regulate T lymphocyte emigration from the circulation into lymph nodes during an immune response and contribute significantly to the immunologic outcome.