Production of anti-double-stranded DNA antibodies in activated lymphocyte derived DNA induced lupus model was dependent on CD4+ T cells

Our previous study demonstrated that activated lymphocyte derived DNA (ALD-DNA) could function as an autoantigen to induce production of anti-double-stranded DNA (anti-dsDNA) antibodies in syngeneic BALB/c mice. Here we carefully evaluated the potential role of T cells in the induction of anti-dsDNA antibody. We demonstrated that ALD-DNA could effectively induce production of anti-dsDNA antibodies in vivo and in vitro. In contrast, ALD-DNA could not induce the generation of anti-dsDNA antibodies in nude mice. We further showed that in vivo depletion of CD3+ T cells blocked the induction of anti-dsDNA antibodies in BALB/c mice. Notably, we demonstrated that CD4+ but not CD8+ T cells conferred ALD-DNA to induce anti-dsDNA antibodies. Finally, we demonstrated that adoptive transfer of CD4+ T cells could rescue ALD-DNA induced anti-dsDNA antibodies in nude mice. Our results suggested that T helper cells were required for ALD-DNA to induce anti-dsDNA antibodies. These findings could further our understanding about the immunogenic properties of DNA and throw new light on SLE pathogenesis.

The RNA helicase RHAU (DHX36) unwinds a G4-quadruplex in human telomerase RNA and promotes the formation of the P1 helix template boundary

Human telomerase RNA (hTR) contains several guanine tracts at its 5′-end that can form a G4-quadruplex structure. Previous evidence suggests that a G4-quadruplex within this region disrupts the formation of an important structure within hTR known as the P1 helix, a critical element in defining the template boundary for reverse transcription. RNA associated with AU-rich element (RHAU) is an RNA helicase that has specificity for DNA and RNA G4-quadruplexes. Two recent studies identify a specific interaction between hTR and RHAU. Herein, we confirm this interaction and identify the minimally interacting RNA fragments. We demonstrate the existence of multiple quadruplex structures within the 5′ region of hTR and find that these regions parallel the minimal sequences capable of RHAU interaction. We confirm the importance of the RHAU-specific motif in the interaction with hTR and demonstrate that the helicase activity of RHAU is sufficient to unwind the quadruplex and promote an interaction with 25 internal nucleotides to form a stable P1 helix. Furthermore, we have found that a 5′-terminal quadruplex persists following P1 helix formation that retains affinity for RHAU. Finally, we have investigated the functional implications of this interaction and demonstrated a reduction in average telomere length following RHAU knockdown by small interfering RNA (siRNA).

An optofluidic prism tuned by two laminar flows

This paper presents a tunable optofluidic prism based on the configuration of two laminar flow streams with different refractive indices in a triangular chamber. The chambers with 70° and 90° apex angles are designed based on simulation results, which provide the optimum working range and avoid recirculating flows in the chambers. In addition, a hydrodynamic model has been developed to predict the tuning of the prisms by the variation in the flow rates. Prisms with different refractive indices are realized using benzyl alcohol and deionized (DI) water as the inner liquids, respectively. The mixture of ethylene glycol and DI water with an effective refractive index matched to that of the microchannel is used as the outer liquid. The apex angle of the prism is tuned from 75° to 135° by adjusting the ratio of the two flow rates. Subsequently, the deviation angle of the output light beam is tuned from -13.5° to 22°. One of the new features of this optofluidic prism is its capability to transform from a symmetric to an asymmetric prism with the assistance of a third flow. Two optical behaviours have been performed using the optofluidic prism. First, parallel light beam scanning is achieved with a constant deviation angle of 10° and a tuning range of 60 μm using the asymmetric prism. The detected output light intensity is increased by 65.7%. Second, light dispersion is experimentally demonstrated using 488-nm and 633-nm laser beams. The two laser beams become distinguishable with a deviation angle difference of 2.5° when the apex angle of the prism reaches 116°.

Tumour necrosis factor alpha -308G/A polymorphism and risk of the four most frequent cancers: a meta-analysis

The latest data show that breast, prostate, lung and colorectal cancer are the four most frequent cancers in both sexes worldwide. A number of molecular epidemiological studies have been conducted to examine the association between TNF alpha -308G/A and the risk of those cancers. However the results have been inconclusive or inconsistent. We then performed a meta-analysis to derive a precise estimation of this association. We carried out a comprehensive search in Medline, EMBASE, OVID and Chinese Biomedical Literature Database for studies using related keywords. The inclusion criteria were (i) in English or Chinese; (ii) case-control study on this association; (iii) provide usable genotype frequencies; and (iv) sufficient published data for estimating an odds ratio (OR) with 95% confidence interval (CI). ORs and 95% CIs were calculated to assess the strength of this association under homozygote comparison (AA vs GG), heterozygote comparison (GA vs GG), dominant (AA/GA vs GG) and recessive (AA vs GA/GG) genetic model comparison. Thirty case-control studies with a total number of 16,507 cases and 19,749 controls were selected for analysis. Overall, no significant association was found between this polymorphism and the risk of total four cancers (GA vs GG: OR=1.02, 95% CI=0.91-1.14, P=0.78). However, there was a significant association between this polymorphism and breast cancer risk in western populations (GA vs GG: OR=0.91, 95% CI=0.85-0.96, P=0.002). This meta-analysis also revealed that this polymorphism was not associated with susceptibility to the other three cancers.

Lactoferrin-derived peptides and Lactoferricin chimera inhibit virulence factor production and biofilm formation in Pseudomonas aeruginosa

AIMS

To investigate the bactericidal activity of lactoferrin-derived peptides and a new LF-derived peptides chimera (LFchimera) against P. aeruginosa and the influence on virulence factors of P. aeruginosa.

METHODS AND RESULTS

Lactoferricin (LFcin) and lactoferrampin (LFampin) are highly bioactive peptides isolated from the N-terminal region of lactoferrin (LF) by pepsin digestion. In this study, we designed LFchimera containing LFcin amino acids 17-30 and LFampin amino acids 268-284. Pseudomonas aeruginosa cells were incubated in medium with peptides at different concentrations, and then the assays of viability, pyocyanin, elastase activity and biofilm formation of P. aeruginosa were performed. We found that the concentration-dependent antibactericidal activity and down-regulating pyocyanin, elastase and biofilm formation of LFchimera were significantly stronger than those of LF, LFcin, LFampin or LFcin plus LFampin.

CONCLUSIONS

Our results indicated that LF, LFcin, LFampin and LFchimera were potential candidates to combat P. aeruginosa, and LFchimera was the most effective in them.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new LFchimera has better activity against P. aeruginosa than LF, LFcin and LFampin and may be a promising new compound for treatment of P. aeruginosa infection.

Expression of LHRH receptors in prostate cancer cells prior to therapy, following castration, or following treatment with LHRH agonists

5163

Background: In the treatment of advanced prostate cancer, the effects of luteinizing hormone releasing hormone (LHRH) agonists are mediated through the down-regulation of pituitary LHRH receptors, inhibiting the pituitary-gonadal axis. Several groups have demonstrated LHRH receptor expression on prostate cancer cells. These tumoral receptors have been shown to mediate direct inhibitory effects in vitro. That expression of LHRH receptors persists in the castrate resistant state. To date, there is no information on LHRH receptor expression on the prostate after LHRH agonist therapy. This study investigates the expression of LHRH receptors following prolonged exposure to LHRH agonists. Methods: Expression of LHRH receptors was determined using immunohistochemistry and the intensity was graded on a scale from zero to 3. The expression was analyzed in three cohorts of patients: (1) 47 men with localized prostate cancer treated with radical prostatectomy with no hormone therapy, (2) 61 men with localized prostate cancer treated with neoadjuvant LHRH agonists for varying duration prior to prostatectomy, and (3) 22 men with metastatic prostate cancer who received a palliative transurethral resection of the prostate after clinical progression. In the final cohort, 15 men were treated with castration and 7 were treated with LHRH agonists. Results: 45 of 47 hormone naïve samples (95.7%) demonstrated LHRH receptor expression. Statistical analysis revealed a correlation between strong receptor expression and higher pathologic tumor stage as well as shorter overall survival. 60 of 61 samples treated with neoadjuvant LHRH agonist therapy (98.4%) demonstrated LHRH receptor expression. All 22 samples from patients with metastatic disease demonstrated LHRH receptor expression. The majority of these samples demonstrated moderate to strong intensity. Conclusions: LHRH receptors are expressed on prostate cancers cells of hormone naïve and castrated patients. The expression of these receptors appears to persist despite prolonged treatment with LHRH agonists. The continued expression of these receptors supports the concept of targeting prostatic LHRH receptors to deliver cytotoxic therapy based on LHRH analogs, such as AN-152.

[Table: see text]

Nonlinear spectral imaging of human hypertrophic scar based on two-photon excited fluorescence and second-harmonic generation

BACKGROUND

A noninvasive method using microscopy and spectroscopy for analysing the morphology of collagen and elastin and their biochemical variations in skin tissue will enable better understanding of the pathophysiology of hypertrophic scars and facilitate improved clinical management and treatment of this disease.

OBJECTIVE

To obtain simultaneously microscopic images and spectra of collagen and elastin fibres in ex vivo skin tissues (normal skin and hypertrophic scar) using a nonlinear spectral imaging method, and to compare the morphological structure and spectral characteristics of collagen and elastin fibres in hypertrophic scar tissues with those of normal skin, to determine whether this approach has potential for in vivo assessment of the pathophysiology of human hypertrophic scars and for monitoring treatment responses as well as for tracking the process of development of hypertrophic scars in clinic.

METHODS

Ex vivo human skin specimens obtained from six patients aged from 10 to 50 years old who were undergoing skin plastic surgery were examined. Five patients had hypertrophic scar lesions and one patient had no scar lesion before we obtained his skin specimen. A total of 30 tissue section samples of 30 mum thickness were analysed by the use of a nonlinear spectral imaging system consisting of a femtosecond excitation light source, a high-throughput scanning inverted microscope, and a spectral imaging detection system. The high-contrast and high-resolution second harmonic generation (SHG) images of collagen and two-photon excited fluorescence (TPEF) images of elastin fibres in hypertrophic scar tissues and normal skin were acquired using the extracting channel tool of the system. The emission spectra were analysed using the image-guided spectral analysis method. The depth-dependent decay constant of the SHG signal and the image texture characteristics of hypertrophic scar tissue and normal skin were used to quantitatively assess the amount, distribution and orientation of their collagen and elastin components.

RESULTS

Our experiments and data analyses demonstrated apparent differences between hypertrophic scar tissue and normal skin in terms of their morphological structure and the spectral characteristics of collagen and elastin fibres. These differences can potentially be used to distinguish hypertrophic scar tissues from normal skin and to evaluate treatment responses.

CONCLUSIONS

All the measurements were performed in backscattering geometry and demonstrated that nonlinear spectral imaging has the ability to differentiate hypertrophic scar tissue from normal skin based on noninvasive SHG imaging, and TPEF imaging revealed the microstructure and spectral features of collagen and elastin fibres. With the advances in spectral imaging apparatus miniaturization, we have good reason to believe that this approach can become a valuable tool for the in vivo pathophysiology study of human skin hypertrophic scars and for assessing the treatment responses of this disfiguring disease in clinic. It can also be used to track the development of hypertrophic scars and to study wound healing processes in a noninvasive fashion without biopsy, fixation, sectioning and the use of exogenous dyes or stains.

An aberrant protein complex in CSF as a biomarker of Alzheimer disease

OBJECTIVE

To determine if an aberrant protein complex consisting of prostaglandin-d-synthase (PDS) and transthyretin (TTR) in CSF differentiates between subjects with Alzheimer disease (AD) and normal control (NC) subjects.

METHODS

Western blot analysis and a unique sandwich ELISA were used to quantify levels of complexed PDS/TTR in ventricular CSF of subjects with autopsy-verified diagnoses and in lumbar CSF of living subjects with mild to moderate probable AD and age-matched NC subjects. Ventricular CSF was obtained from short postmortem interval autopsies of 7 NC subjects (4 men/3 women), 12 diseased control (DC) subjects (7 men/5 women), 4 subjects with mild cognitive impairment (MCI) (2 men/2 women), and 8 subjects with late-stage AD (LAD) (4 men/4 women). Lumbar CSF was obtained from 15 subjects with probable AD (5 men/10 women) and 14 age-matched NC subjects (10 men/4 women) and was analyzed in a double-blind fashion.

RESULTS

A significant increase in complexed PDS/TTR in ventricular CSF was found in MCI and LAD subjects but not DC subjects compared with NC subjects. Double-blind analysis of complexed PDS/TTR in lumbar CSF showed a significant sixfold increase in levels of the PDS/TTR complex in living probable AD subjects compared with age-matched NC subjects and a 100% sensitivity and 93% specificity in the identification of subjects with AD.

CONCLUSION

After further study of larger numbers of patients, quantifying prostaglandin-d-synthase/transthyretin complex in CSF may be useful in the diagnosis of Alzheimer disease, possibly in the early stages of the disease.

The p53-Mdm2 network in progenitor cell expansion during mouse postnatal development

Mdm2, an E3 ubiquitin ligase, negatively regulates the tumour suppressor p53. Loss of Mdm2 in mice results in p53-dependent apoptosis and embryonic lethality. This phenotype was rescued by the p53(515C) allele, which encodes an apoptosis-deficient p53R172P protein. However, these mice died within 2 weeks of birth, due to a severe impairment of progenitor cell expansion during postnatal haematopoiesis and cerebellar development, leading to p53-dependent cell cycle arrest. Loss of Mdm2 led to phosphorylation of the p53R172P protein, p53R172P stability and activation of the cell cycle inhibitor p21 in proliferating cells, but not in differentiated cells, in multiple tissue compartments. Proliferating cells of epithelial origin were not affected. The haematopoietic and neural defects were alleviated in mice lacking Mdm2 and containing one p53(515C) and one p53-null allele, but spermatogenesis was arrested. These findings establish a crucial role for the p53-Mdm2 network in regulating proliferation and progenitor expansion in many cell lineages and have important implications for the use of drugs that aim to disrupt the p53-Mdm2 interaction.

Involvement of cellular death in TRAIL/DR5-dependent suppression induced by CD4(+)CD25(+) regulatory T cells

CD4(+)CD25(+) regulatory T cells (Treg) are potent immunosuppressive cells active in controlling normal pathological immune responses. The mechanisms of this suppression have been investigated under various conditions. In this report, tumor necrosis factor-related apoptosis inducing ligand (TRAIL)/death receptor 5 (DR5) was explored as one of the pivotal factors for the suppression and cytotoxicity induced by CD4(+)CD25(+) Treg. Cell death was involved in the suppression induced by activated CD4(+)CD25(+) Treg in vitro. The induction of CD4(+) T cell death was not mediated by the CD95/CD95L pathway, but rather depended upon the upregulation of TRAIL in the Treg. Blocking the TRAIL/DR5 pathway resulted in a significant reduction of the suppressive activity as well as the cytotoxic effects of Treg in vitro. Activated Treg displayed TRAIL-dependent cytotoxicity against CD4(+) T cells in vivo. The prolonged survival of allogeneic skin grafts induced by Treg was inhibited by DR5-blocking antibodies. Our findings suggest that the TRAIL/DR5 pathway is one of the mechanisms used by Treg to regulate immune responses both in vitro and in vivo.

Using an image-guided navigation system for localization of small pulmonary nodules before thoracoscopic surgery

BACKGROUND

Video-assisted thoracic surgery (VATS) provides a minimally invasive means to resect small pulmonary nodules (SPN). However, thoracoscopy has limits in the detection of small nodules, which are invisible and/or impalpable during surgery. Methods to localize such lesions, including methylene blue injection or the introduction of a hookwire under the guidance of computed tomography (CT), have some limitations. We are developing a new technique using image-guided navigation system for localization of small pulmonary nodules before thoracoscopic surgery.

METHODS

Four pigs underwent spiral-computed tomography (CT) scanning after they were given percutaneously created pulmonary lesions. The CT data were transmitted to a StealthStation navigation system, and with the help of the probe the lesions were located and resected under thoracoscopy.

RESULTS

A total of 20 lesions were created. Nodules were located at an average distance of 15.6 mm from the pleural surface. All the lesions were successfully localized, and biopsy specimens revealed successful resection of target material.

CONCLUSION

This method can provide appropriate guidance to small pulmonary nodules and prove effective in immediately facilitating subsequent thoracoscopic resection.

Gene amplification and associated loss of 5' regulatory sequences of CoAA in human cancers

CoAA is an RRM-containing transcriptional coactivator that stimulates transcriptional activation and regulates alternative splicing. We show that the CoAA gene is amplified at the chromosome 11q13 locus in a subset of primary human cancers including non-small cell lung carcinoma, squamous cell skin carcinoma and lymphoma. Analysis of 42 primary tumors suggests that CoAA amplifies independently from the CCND1 locus. Detailed mapping of three CoAA amplicons reveals that the amplified CoAA gene is consistently located at the 5' boundaries of the amplicons. The CoAA coding and basal promoter sequences are retained within the amplicons but upstream silencing sequences are lost. CoAA protein is overexpressed in tumors containing the amplified CoAA gene. RNA dot blot analysis of 100 cases of primary tumors suggests elevated CoAA mRNA expression. CoAA positively regulates its own basal promoter in transfection assays. Thus, gene amplification, loss of silencing sequence and positive feedback regulation may lead to drastic upregulation of CoAA protein. CoAA has transforming activities when tested in soft agar assays, and CoAA is homologous to oncoproteins EWS and TLS, which regulate alternative splicing. These data imply that CoAA may share a similar oncogenic mechanism with oncogene EWS and that CoAA deregulation may alter the alternative splicing of target genes.

Altered expression of zinc transporters-4 and -6 in mild cognitive impairment, early and late Alzheimer's disease brain

Accumulating evidence suggests that a disruption of zinc (Zn) homeostasis may play a role in the pathogenesis of Alzheimer's disease. Although several Zn transporter proteins responsible for the regulation of Zn balance are present in the brain, there has been little study of these proteins in Alzheimer's disease. To determine if alterations of Zn transporter proteins exist, levels of Zn transporter-4, which functions to remove Zn from the cytoplasm to endosomal/lysosomal compartments, and Zn transporter-6, which allocates cytoplasmic Zn to the trans-Golgi network, were measured in the hippocampus/parahippocampal gyrus, superior and middle temporal gyrus, and cerebellum of subjects with mild cognitive impairment, early Alzheimer's disease, late stage Alzheimer's disease, and age-matched controls using Western blot analysis and protein specific antibodies. Our results show that Zn transporter-4 and Zn transporter-6 are significantly (P<0.05) increased in hippocampus/parahippocampal gyrus of early Alzheimer's disease and Alzheimer's disease subjects. Zn transporter-6 is also increased (P<0.1) in the superior and middle temporal gyrus of Alzheimer's disease brain.

4-Hydroxynonenal disrupts zinc export in primary rat cortical cells

Accumulating evidence implicates oxidative stress in the pathogenesis of several neurodegenerative disorders including Alzheimer's disease (AD). Increased lipid peroxidation, decreased levels of polyunsaturated fatty acids, and increased levels of 4-hydroxynonenal (HNE) have been demonstrated in AD brain. Proteins responsible for zinc export are localized on the plasma membrane and may be vulnerable to damage from lipid peroxidation. To test this hypothesis, cultured primary rat cortical neurons were incubated with (65)Zn for 1h and then treated with HNE (0-35 microM) for 4 h. Levels of (65)Zn in aliquots of medium were measured at 1, 2, 4h following treatment with HNE and intracellular (65)Zn measured after 4h using liquid scintillation counting. The amount of (65)Zn in medium did not differ significantly. However, a statistically significant (p<0.05) increase of (65)Zn was observed inside cortical neurons after treatment with 20 microM HNE for 4 hours. These data suggest that HNE may impair a protein essential for zinc export leading to increased levels of intracellular zinc.

Th2-dominated antitumor immunity induced by DNA immunization with the genes coding for a basal core peptide PDTRP and GM-CSF

Our previous study showed that DNA vaccination with a plasmid vector encoding a core peptide of mucin1 (PDTRP) provided modest protection against challenge with tumor cells that expressed mucin1 protein. We report here that a DNA vaccine comprising a modified PDTRP plasmid and GM-CSF coding sequence at the C-terminus induced better protection against tumor challenge. The increased protection was directly correlated with a stronger PDTRP-specific immune response induced by the GM-CSF fusion plasmid. The plasmid encoding GM-CSF and the target PDTRP antigen induced a greater PDTRP-specific Th proliferation, antibodies, and cytotoxicity. Interestingly, the modified plasmid vaccine predominantly enhanced the type 2 immune responses manifested by an increased IgG1 to IgG2a antibody ratio and a greater induction of GATA-3 and IL-4 mRNA than that of T-bet and IFN-gamma mRNA in spleen cells from vaccinated mice. In addition, protection against tumor challenge in vaccinated mice showed that there was no significant change in mice survival after in vivo CD8+CTL depletion, indicating that antitumor immunity augmented by plasmid encoding GM-CSF and target PDTRP gene vaccine was dominated by Th2 immune response.

Increased oxidative damage in nuclear and mitochondrial DNA in Alzheimer's disease

Increasing evidence suggests that oxidative stress is associated with normal aging and several neurodegenerative diseases, including Alzheimer's disease (AD). Here we quantified multiple oxidized bases in nuclear and mitochondrial DNA of frontal, parietal, and temporal lobes and cerebellum from short postmortem interval AD brain and age-matched control subjects using gas chromatography/mass spectrometry with selective ion monitoring (GC/MS-SIM) and stable labeled internal standards. Nuclear and mitochondrial DNA were extracted from eight AD and eight age-matched control subjects. We found that levels of multiple oxidized bases in AD brain specimens were significantly (p < 0.05) higher in frontal, parietal, and temporal lobes compared to control subjects and that mitochondrial DNA had approximately 10-fold higher levels of oxidized bases than nuclear DNA. These data are consistent with higher levels of oxidative stress in mitochondria. Eight-hydroxyguanine, a widely studied biomarker of DNA damage, was approximately 10-fold higher than other oxidized base adducts in both AD and control subjects. DNA from temporal lobe showed the most oxidative damage, whereas cerebellum was only slightly affected in AD brains. These results suggest that oxidative damage to mitochondrial DNA may contribute to the neurodegeneration of AD.

Alterations in zinc transporter protein-1 (ZnT-1) in the brain of subjects with mild cognitive impairment, early, and late-stage Alzheimer's disease

Several studies show increased levels of zinc (Zn) in the Alzheimer's disease (AD) brain. More recently, alterations in synaptic Zn and Zn transporter proteins (ZnT) have been implicated in the accumulation of amyloid plaques in an animal model of AD. To determine if alterations in ZnT proteins are present in AD brain, we measured levels of ZnT-1, the protein responsible for export of Zn to the extracellular space in the amygdala (AMY), hippocampus/parahippocampal gyrus (HPG), superior and middle temporal gyrus (SMTG), inferior parietal lobule (IPL), and cerebellum (CER) of 19 AD and 14 age-matched control subjects. To determine if alterations of ZnT-1 occur early in the progression of AD, we analyzed protein levels in the HPG, SMTG and CER of 5 subjects with mild cognitive impairment (MCI), 5 subjects with early AD (EAD) and 4 appropriately age-matched controls. Western blot and dot-blot analysis showed statistically significant (p 0.05) elevations of ZnT-1 in AD AMY, HPG, and IPL and significantly depleted ZnT-1 in AD SMTG compared to age-matched control subjects. We also observed statistically significant elevations of ZnT-1 in the HPG of EAD subjects compared with controls. In contrast to late-stage AD subjects, ZnT-1 levels were significantly decreased in HPG of subjects with MCI and were significantly elevated in the SMTG of both MCI and EAD subjects compared with age-matched controls. Correlation analysis of ZnT-1 levels and senile plaque (SP) and neurofibrillary tangle (NFT) counts in the AMY and CA1 and subiculum of AD HPG showed a significant (p 0.05) positive correlation with SP counts and a trend towards a significant (p = 0.12) positive correlation with NFT counts in AMY. Overall, our results show alterations in one of the key proteins responsible for maintenance of Zn homeostasis early in the progression of AD suggesting that alterations in Zn balance could be involved in the pathogenesis of neuron degeneration and amyloid deposition in AD.

Activity of adefovir dipivoxil against all patterns of lamivudine-resistant hepatitis B viruses in patients

One hundred and thirty-one post-liver transplantation patients with chronic hepatitis B and failing lamivudine therapy with detectable serum hepatitis B virus (HBV) deoxyribonucleic acid by hybridization assays or > or =1 x 10(6) copies/mL by polymerase chain reaction, and elevated alanine transaminase levels despite continuous lamivudine, were enrolled in an open-label study of adefovir dipivoxil. The B and C domains of HBV polymerase were sequenced for baseline samples to determine the presence of lamivudine resistance mutations. The results showed that 98% of the samples had tyrosine-methionine-aspartate-aspartate (YMDD) mutations, indicating a strong correlation between the above clinical definition of lamivudine treatment failure and the presence of YMDD mutations. In addition to the rtM204V/I and the rtL180M mutations, the mutation rtV173L was identified in 19% of patients. Four major patterns of lamivudine-resistant HBV were identified: rtL180M + rtM204V (60%), rtV173L + rtL180M + rtM204V (19%), rtM204I (9%) and rtL180M + rtM204I (9%). Treatment with adefovir dipivoxil showed similar antiviral efficacy in patients with lamivudine-resistant virus from all four patterns.

Allogenic donor splenocytes pretreated with antisense peptide against B7 prolong cardiac allograft survival

The interaction of T cell CD28/CTLA-4 receptors with B7 on antigen-presenting cells (APCs) represents an important co-stimulatory pathway in T cell activation or anergy. Our previous study indicated that recipients immunized with allogenic donor immature dendritic cells (DCs) or resting B cells could induce specific immune tolerance and prolong allograft survival. A possible mechanism for this observation is that the expression of B7 molecules is either at a low level or lacking on these cells. The present study investigates whether blockade of B7 molecules on donor splenocytes with a B7 antisense peptide (B7AP), i.e. a peptide analogue of the CD28-binding region, could induce specific immune tolerance and prolong allograft survival in the recipients. Both the lymphocyte proliferation reaction and the mice pinna cardiac allograft experiment were performed to evaluate the role of B7AP in inducing specific immune tolerance in recipients in vitro and in vivo. The results showed that 56.65% and 20.52% of C57BL/6 splenocytes expressed B7.1 and B7.2 molecules, respectively, on their cell surface. There were no significant changes of the B7 expression on such splenocytes after being treated by the B7AP (53.28% and 19.06%, respectively). B7AP inhibited the mixed lymphocyte reaction by up to 38.4% and a dose-response correlation was observed for inhibition. The recipients (BALB/c) immunized with B7AP-pretreated C57BL/6 splenocytes induced a specific immune hypo-response (43%versus control) and notably prolonged survival of the C57BL/6 cardiac allograft by up to 20.3 days. In contrast to the normal saline group (average: 8.6 days) and FTD(10) control peptide group (<4 days), the cardiac allograft survival of the test group was extended for an additional 11.7 days. These results strongly support the notion that immunization with donor splenocytes, which had been pretreated with B7AP, induced specific immune tolerance and prolonged allograft survival in the recipients.

Adefovir dipivoxil alone or in combination with lamivudine in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND AND AIMS

Adefovir dipivoxil possesses potent in vitro and in vivo antiviral activity in wild-type hepatitis B. This study assessed the safety and efficacy of adefovir dipivoxil alone and in combination with lamivudine compared with ongoing lamivudine therapy in patients with chronic hepatitis B with compensated liver disease and lamivudine-resistant hepatitis B virus (HBV).

METHODS

Fifty-nine hepatitis B e antigen (HBeAg)-positive patients with genotypic evidence of lamivudine-resistant HBV, serum alanine aminotransferase (ALT) level > or =1.2 times the upper limit of normal, and serum HBV DNA level > or =6 log(10) copies/mL despite ongoing treatment with lamivudine were randomized to adefovir dipivoxil 10 mg, lamivudine 100 mg, or addition of adefovir dipivoxil to ongoing lamivudine daily. The primary end point was the time-weighted average change from baseline in serum HBV DNA level (DAVG) up to week 16.

RESULTS

Rapid reductions in serum HBV DNA level were seen by 4 weeks in all recipients of adefovir dipivoxil; DAVG(16) was -0.07 in the lamivudine group compared with -2.45 and -2.46 log(10) copies/mL in the adefovir dipivoxil/lamivudine and adefovir dipivoxil monotherapy groups, respectively (P < 0.001). Median change from baseline in serum HBV DNA level at week 48 was 0.0, -3.59, and -4.04 log(10) copies/mL in the lamivudine, adefovir dipivoxil/lamivudine, and adefovir dipivoxil groups, respectively. ALT level normalized in 10 of 19 (53%) and 9 of 18 (47%) recipients of adefovir dipivoxil/lamivudine and adefovir dipivoxil, respectively, compared with 1 of 19 (5%) recipients of lamivudine. Three patients receiving adefovir dipivoxil or adefovir dipivoxil/lamivudine and none receiving lamivudine monotherapy were HBeAg negative at week 48 and one became hepatitis B surface antigen negative.

CONCLUSIONS

These data, limited to patients with compensated liver disease, indicate that adefovir dipivoxil alone or in combination with ongoing lamivudine therapy provides effective antiviral therapy in patients with lamivudine-resistant HBV.

The diagnosis value and its implication of impulse oscillometry in obstructive sleep apnea syndrome patients

The change of measurements of impulse oscillometry (IOS) in obstructive sleep apnea syndrome (OSAS) patients and its mechanism were observed. The respiratory impedance was measured by using IOS technique and polysomnography (PSG) was monitored synchronously in 36 OSAS patients, 14 patients with chronic obstructive pulmonary disease (COPD) and 12 normal controls. Results showed that R20 in OSAS group was significantly higher than in COPD group and control group (P < 0.01). R5-R20 in OSAS group was lower than that in COPD group, but significantly higher than that in control group (P < 0.01). The levels of R20 and R5-R20 were positively correlated with severity degree of the disease. In addition, apnea-hyponea index (AHI) was positively correlated with R5 and R20 with the correlation index (r)being 0.66 and 0.86 respectively. The lowest SO2 was negatively correlated with R5 and R5-R20, with r being -0.66 and -0.79 respectively. The mean SO2 was negatively correlated with R5 and R5-R20 with r being -0.81 and -0.69 respectively. IOS technique could be used as a valuable tool for assessing the degree of upper airway obstruction in the patients with OSAS, and could help to explore its pathological mechanism.

[Intestinal bacterial translocation in patients with biliary tract diseases]

To determine whether intestinal bacterial translocation occurs in man, the authors cultured the tissues of mesenteric lymph nodes(MLNs), bile, portal and peripheral venous blood obtained prior to and during operation in 35 patients with biliary diseases. No positive peritoneal swab, portal blood and peripheral blood culture were shown. Thirteen of 20 patients with biliary obstruction (65%) had bacteria in their MLNs, while no positive MLN culture was found in 12 patients without biliary obstruction. The most common bacteria recovered from the MLNs were Gram-negative enteric bacilli. Thus, it is considered that extrahepatic biliary obstruction may induce intestinal bacterial translocation in man.

Multiple signaling pathways involved in activation of matrix metalloproteinase-9 (MMP-9) by heregulin-beta1 in human breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays important roles in tumor invasion and angiogenesis. Secretion of MMP-9 has been reported in various cancer types including lung cancer, colon cancer, and breast cancer. In our investigation of MMP-9 regulation by growth factors, MMP-9 was activated by heregulin-beta1 as shown by zymography in both SKBr3 and MCF-7 breast cancer cell lines. Increase in MMP-9 activity was due to increased MMP-9 protein and mRNA levels, which mainly results from transcriptional upregulation of MMP-9 by heregulin-beta1. Heregulin-beta1 activates multiple signaling pathways in breast cancer cells, including Erk, p38 kinase, PKC, and PI3-K pathways. We examined the pathways involved in heregulin-beta1-mediated MMP-9 activation using chemical inhibitors that specifically inhibit each of these heregulin-beta1-activated pathways. The PKC inhibitor RO318220 and p38 kinase inhibitor SB203580 completely blocked heregulin-beta1-mediated activation of MMP-9. MEK-1 inhibitor PD098059 partially blocked MMP-9 activation, whereas PI3-K inhibitor wortmannin had no effect on heregulin-beta1-mediated MMP-9 activation. Therefore, at least three signaling pathways are involved in the activation of MMP-9 by heregulin-beta1. Since MMP-9 is tightly associated with invasion/metastasis and angiogenesis, our studies suggest that blocking heregulin-beta1-mediated activation of MMP-9 by inhibiting the related signaling pathways may provide new strategies for inhibition of cancer metastasis and angiogenesis.

Three novel high performance affinity chromatographic media for the separation of antithrombin III from human plasma

Novel monodisperse, non-porous, cross-linked poly (glycidyl methacrylate) beads (PGMA) were employed as the support for high performance affinity chromatography. Heparin was covalently attached to PGMA beads by three different coupling methods. Heparin-PGMA-I was prepared by directly coupling amino-groups of heparin with PGMA. Heparin-PGMA-II and III were prepared by the coupling of heparin to amino-PGMA, which was obtained by amination of PGMA. Heparin-PGMA-II was prepared by coupling the carboxyl groups of heparin to amino-PGMA by using water-soluble carbodiimide as coupling reagent, and heparin-PGMA-III was prepared by the reductive amination of heparin and amino-PGMA with sodium cyanoborohydride. The heparin contents of heparin-PGMA-I, II and III were 1.6, 10.2 and 1.0 mg/g beads, respectively. Their affinity capacities for antithrombin III were investigated. Their binding activity to antithrombin III was not proportional to the content of heparin immobilized, and heparin-PGMA-I was the most efficient affinity medium for antithrombin III. The resultant affinity media presented minimal non-specific interaction with other proteins and can be used in a wide pH range. All the three heparin-PGMA beads were exploited for the separation of antithrombin III from human plasma. The purity of antithrombin III obtained was higher than 90%, which was confirmed by high performance size exclusion chromatography.

Novel rhodopsin mutation in a Chinese family with autosomal dominant retinitis pigmentosa

PURPOSE

To identify mutations in the rhodopsin (RHO) gene in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) and to measure the prevalence rate of RHO mutations in Chinese ADRP cases.

METHODS

Thirteen Chinese families with ADRP were clinically characterized. The complete coding region and intron splice sites of RHO were analyzed for mutations with single-strand conformation polymorphism (SSCP) analysis and direct genomic sequencing.

RESULTS

One of the 13 Chinese families with ADRP was found to have a new, previously unidentified RHO mutation, a change from GAG to TAG at codon 341. The mutation (E341X) results in an in-frame stop codon, leading to the truncation of the rhodopsin protein. Mutation E341X was not detected in 100 normal control individuals. Patients carrying mutation E341X reported night blindness and showed optic atrophy, vessel attenuation, and a few bone spicule-like pigments in peripheral retina at the age of 23-25 years. At the age of 30 years, visual acuity was severely impaired, peripheral visual field was greatly constricted, rod and cone ERG was not detectable, and only a slight left cone response remained.

CONCLUSIONS

We have identified a novel rhodopsin mutation (E341X) in a Chinese family with ADRP. The location and character of the mutation expand the spectrum of RHO mutations causing RP. Identification of a RHO mutation in one of the 13 ADRP families studied suggests that only 7.7% of the ADRP cases in a Chinese population were caused by RHO mutations, a ratio significantly lower than that from North America or Europe.

[Effect of platelet on procoagulant activity of monocyte]

OBJECTIVE

To investigate the effect of platelet on procoagulant activity of mononcyte(M).

METHODS

The procoagulant activity of M lysates was measured by one stage clotting time assay, the tissue factor (TF) activity and the role of P-selectin were confirmed by specific monoclonal antibodies (McAb).

RESULTS

1. Activated M challenged by lipopolysaccharide(LPS) had augmented procoagulant activity and this effect was blocked by TF McAb. 2. Procoagulant activity of M and activated M increased significantly with the presence of activated platelets. 3. The enhancement effect of activated platelet on the procoagulant activity of M was blocked by P-selectin McAb.

CONCLUSION

TF expression of M contributes to the procoagulant activity of Ms and activated platelet enhances the procoagulant activity via P-selectin.

Optical processing of light-induced autofluorescence for characterization of tissue pathology

We describe an optical processing method for characterizing tissue pathology that is based on principal-component analysis of light-induced autofluorescence. A set of optical spectral filters, which are related to the principal-component loading vectors, is designed to process the autofluorescence signal optically and to generate principal-component scores from the autofluorescence spectra. The scores are then correlated with the tissue pathology. An optical processing system is designed that uses the in vivo fluorescence spectra recorded from nasopharyngeal tissues. We demonstrate that the system can differentiate nasopharyngeal carcinoma from normal tissue with a high degree of sensitivity and specificity and that the optical filters used in the system can be manufactured.

Expression of glutathione-S-transferase isozyme in the SY5Y neuroblastoma cell line increases resistance to oxidative stress

Glutathione-S-transferases (GSTs) are a superfamily of enzymes that function to catalyze the nucleophilic attack of glutathione on electrophilic groups of a second substrate. GSTs are present in many organs and have been implicated in the detoxification of endogenous alpha, beta unsaturated aldehydes, including 4-hydroxynonenal (HNE). Exogenous GST protects hippocampal neurons against HNE in culture. To test the hypothesis that overexpression of GST in cells would increase resistance to exogenous or endogenous HNE induced by oxidative stress, stable transfectants of SY5Y neuroblastoma cells with GST were established. Stable GST transfectants demonstrated enzyme activities 13.7 times (Clone 1) and 30 times (Clone 2) higher than cells transfected with vector alone. GST transfectants (both Clones 1 and 2) demonstrated significantly (p <.05) increased resistance to ferrous sulfate/hydrogen peroxide (20.9% for Clone 1; 46.5% for Clone 2), amyloid beta-peptide (12.2% for Clone 1; 27.5.% for Clone 2), and peroxynitrite (24.3% for Clone 1; 43.9% for Clone 2), but not to exogenous application of HNE in culture medium. GST transfectants treated with 1,1,4-tris (acetyloxy)nonane, a nontoxic derivative of HNE that is degraded to HNE intracellularly, demonstrated a statistically significant (p <.05) increase in viability in a dose-dependent manner compared with SY5Y cells transfected with vector alone. These results suggest that overexpression of GST increases resistance to endogenous HNE induced by oxidative stress or released in the degradation of 1,1,4-tris (acetyloxy)nonane, but not to exogenous application of HNE.

The role of factor XI in a dilute thromboplastin assay of extrinsic coagulation pathway

Blood coagulation has been thought to be composed of both intrinsic and extrinsic pathways. Recent evidence strongly supports the critical role of the extrinsic pathway in the initiation of blood coagulation. This investigation established an assay that examines the role of FXI in the thromboplastin-initiated (extrinsic) coagulation based on this new concept. Plasma clotting times were measured at different concentrations of thromboplastin with activated FXII inhibited (FXIIa-inhibited Diluted Thromboplastin Time, FXIIaiDTT). Only at low concentrations of thromboplastin was FXIIaiDTT of FXI-deficient plasma significantly prolonged than that of normal plasma. Depletion of FXI from normal plasma prolonged its FXIIaiDTT and replenishment of FXI shortened it. FXIIaiDTTs of both FVIII-deficient and FIX-deficient plasma were remarkably prolonged, and addition of normal plasma dose-dependently shortened it. Furthermore, earlier alpha-thrombin inhibition was directly correlated with decreasing FXa generation. The amount of FXa production was: platelet-rich plasma > platelet-poor plasma > FXI-deficient plasma. Therefore, our findings from the FXIIaiDTT assays not only support the critical role of extrinsic pathway in blood coagulation initiation, but also demonstrate the importance of FXI as an amplifier of thrombin generation in thromboplastin-initiated coagulation.

Radiation-induced progressive decreasing in the expression of reverse transcriptase gene of hEST2 and telomerase activity

OBJECTIVES

In order to identify the relationship between telomerase and the biological effect of radiation injury, and investigate the role of human telomerase catalytic subunit gene (hEST2) reverse transcriptase(RT) segment in the expression of telomerase activity.

METHODS

Tumor HeLa cells, KB cells and A431 cells were employed to measure the change in telomerase activity after 60Co-ray irradiation at RNA level and protein level. Quantitative PCR and Northern blotting were used to determine the expression of hEST2 RT segment that encodes seven motifs of the human telomeres, a PCR-based telomeric repeat amplification protocol (TRAP) was used to assay telomerase activity after exposure to radiation.

RESULTS

Both of telomerase activity and the expression hEST2 RT segment were decreased with increasing dosage of radiation. In addition, testing the expression of motifs domain is similar to the measurement of telomerase activity.

CONCLUSION

The detection of the hEST2 RT segment by Northern blotting and quantitative PCR are new methods for testing telomerase activity. Furthermore, radiation can cause a dose-dependent decrease in telomerase activity. The effect of radiation on telomerase is one possible reason for the death of cancer cells after irradiation.

[Experimental studies on muscle fatigue of human limb motion with FNS]

The basic characteristic of the functional neuromuscular stimulation signals suitable to body is preliminarily determined after the fatigue performance of the biceps, and the physiological reaction to stimulation is investigated using many continuous stimulation signal patterns. The flexion motion of the elbow joint (right hand) of a healthy man was taken as our research objective. The surface electrodes were connected to the biceps and a micro angle sensor was mounted on the elbow joint (right hand). The curves of angular displacement for the elbow joint motion were obtained by using functional neuromuscular stimulation (FNS) limbs motion measurement instruments. The results demonstrate that the biceps are characterized by the non-linear and time-variant no matter what the stimulation patterns are, that continuous slow stimulation signals can reduce the muscle fatigue of the biceps, and that the stimulation frequencies ranging from 30 Hz to 50 Hz are applicable to the neuromuscular system.

Development of angiotensin (1-7) as an agent to accelerate dermal repair

Angiotensin II has been shown to be a potent agent in the acceleration of wound repair. Angiotensin (1-7), a fragment of angiotensin II that is not hypertensive, was found to be comparable to angiotensin II in accelerating dermal healing. This activity was evaluated in four models: rat and diabetic mouse full-thickness excisional wounds; rat random flap; and guinea pig partial thickness thermal injury. In all models, angiotensin (1-7) was comparable to angiotensin II. Angiotensin (1-7) accelerated the closure of wounds in diabetic mice and rats. In diabetic mice the resultant tissue at day 25 after injury was more comparable to normal tissue than the fibrotic scar observed in placebo-treated wounds. In the random flap model, angiotensin (1-7) was comparable to angiotensin II in maintaining flap viability (approximately 82%) and flap survival (40%). Finally, angiotensin (1-7) increased proliferation in the hair follicles at the edge of the wound and site of thermal injury, and the number of patent blood vessels on day 7 after partial thickness thermal injury. These data may be partially explained by the effect of angiotensin II and angiotensin (1-7) on keratinocyte proliferation. While platelet-derived growth factor had no effect on keratinocyte proliferation, angiotensin II and angiotensin (1-7) significantly increased keratinocyte proliferation. These data show that angiotensin(1-7) is comparable to angiotensin II in accelerating skin repair. Furthermore, the hypertensive and wound healing effects can be separated within the family of angiotensin peptides.

Study on the degeneracy of antisense peptides using affinity chromatography

The degeneracy of antisense peptides was studied by high-performance affinity chromatography. A model sense peptide (AAAA) and its antisense peptides (CGGG, GGGG, RGGG, SGGG) were designed and synthesized according to the degeneracy of genetic codes. An affinity column with AAAA as the ligand was prepared. The affinity chromatographic behaviors of antisense peptides on the column were evaluated. The results indicated that model antisense peptides have clear retention on the immobilized AAAA affinity column. RGGG showed the strongest affinity interaction. Similar result was obtained from another experiment that Arg-substituted antisense peptide of fusion peptide (1-11) of influenza virus A was also shown the highest affinity binding to immobilized fusion peptide.

Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis

OBJECTIVE

To assess the correlation between hepatitis B virus (HBV) surface gene mutant infection and hepatitis B (HB) vaccination failure.

METHODS

Using sera from 106 infants who were born to HBV carrier mothers and failed in HB immunoprophylaxis, HBV S gene was amplified by PCR, transferred to nylon membranes for Southern blots, and then hybridized with oligonucleotide probes. Eleven of non-hybridizing samples were used for DNA sequencing.

RESULTS

93.4% (99/106) of the samples were HBV DNA positive, and 30.3% (30/99) failed to hybridize with at least one of the four probes. DNA sequencing confirmed that 10 of the 11 samples had an S gene mutation with amino acid (aa) change. The identified mutants included nucleotide (nt) 546T-->A (aa131N-->T), nt531T-->C (aa1261-->T), nt491A-->C (aa113T-->P), nt491T-->A (aa113S-->T), nt533C-->A (aa127P-->T), nt581T-->A (aa143S-->T), nt636A-->T (aa161Y-->F), and nt679A-->C (aa175L-->F). The sequence in one mother-infant pair was completely the same, with mutations at aa131 and aa161.

CONCLUSIONS

The prevalence of HBV surface mutants is about 30% in the children failing in HB vaccination. HBV mutants can infect infants by maternal-infant transmission.

Capillary electrophoresis of catecholamines with laser-induced fluorescence intensified charge-coupled device detection

A capillary electrophoresis-laser-induced fluorescence-intensified charge-coupled device system was used for the separation and determination of catecholamines. Optimization of derivatization and separation conditions was investigated in order to reach a high separation efficiency and sensitivity. All fluorecein isothiocyanate derivatives of catecholamines were satisfactorily separated within 12 min. The detection limits were in attomole ranges. This method allows determination of catecholamines with high separation efficiencies and sensitivity.

New method for high-performance liquid chromatographic separation and fluorescence detection of ginsenosides

A novel pre-column derivatization method for the quantitative determination of ginsenosides by HPLC with fluorescence detection was established. The double bond at the C24-C25 position of ginsenoside was converted into an aldehyde group by means of ozonolysis. Then the aldehyde group reacts with FMOC-hydrazine forming the ginsenoside FMOC-hydrazone. The derivatized products were separated by RP-HPLC with gradient elution. The detection limits of ginsenosides Rg1 and Rb1 were 2.0 ng (about 2.5 pmol) and 1.0 ng (about 0.9 pmol), respectively. This method can be used for all ginsenosides having the C24-C25 double bond.

[A study on the use of traditional Chinese medicine agent in ultrasonic instrumentation of root canals]

OBJECTIVE

To evaluate the bactericidal effect for anaerobes of infected root canals using Chinese medicine agent Jieeryin combing with ultrasonic technique.

METHODS

60 single-rooted teeth in patients with chronic periapical periodotitis were divided into 3 groups randomly, 20 in each. Hand instruments were used for group 1 as control group of traditional treatment. Ultrasound with saline as irrigant were used for group 2 as control group. Ultrasound with Jieeryin as irrigant were used for group 3 as experimental group. The pre-instrumentation and post-instrumentation specimens of each root canal were placed into the anaerobic chambers and incubated.

RESULTS

Significant difference was found between hand instruments group and control group of ultrasound (P < 0.05) and even more significant difference was found between control group of ultrasound and experimental group of ultrasound (P < 0.01).

CONCLUSIONS

Ultrasound has special superiority on instrumentation and bactericide of root canals. Chinese medicine agent Jieeryin can kill anaerobes in infected root canals effectively. It is an ideal irrigant for ultrasound which conforms to principles of biology.

Up-regulation of vascular endothelial growth factor in breast cancer cells by the heregulin-beta1-activated p38 signaling pathway enhances endothelial cell migration

Heregulin (HRG) belongs to a family of polypeptide growth factors that bind to receptor tyrosine kinases ErbB3 and ErbB4. HRG binding induces ErbB3 and ErbB4 heterodimerization with ErbB2, activating downstream signal transduction. Vascular endothelial growth factor (VEGF) is a primary regulator of physiological angiogenesis and is a major mediator of pathological angiogenesis, such as tumor-associated neovascularization. In this study, we demonstrate that HRG-beta1 increased secretion of VEGF from breast cancer cells in a time- and dosage-dependent manner and that this increase resulted from up-regulation of VEGF mRNA expression via transcriptional activation of the VEGF promoter. Deletion and mutational analysis revealed that a CA-rich upstream HRG response element located between nucleotide-2249 and -2242 in the VEGF promoter mediated HRG-induced transcriptional up-regulation of VEGF. While investigating the downstream signaling pathways involved in HRG-mediated up-regulation of VEGF, we found that HRG activated extracellular signal-regulated protein kinases, Akt kinase, and p38 mitogen-activated protein kinase (MAPK). However, only the specific inhibitor of p38 MAPK (SB203580), not extracellular signal-regulated kinase inhibitor PD98059 nor the inhibitor of phosphatidylinositol 3-kinase-Akt pathway (Wortmannin), blocked the up-regulation of VEGF by HRG. The HRG-stimulated secretion of VEGF from breast cancer cells resulted in increased migration of murine lung endothelial cells, an activity that was inhibited by either VEGF-neutralizing antibody or SB203580. These results show that HRG can activate p38 MAPK to enhance VEGF transcription via an upstream HRG response element, leading to increased VEGF secretion and angiogenic response in breast cancer cells.

Characterization of tetrathiofulvalene compounds using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Tetrathiofulvalene compounds are important components of charge-transfer complexes, which may be applied in various fields of scientific research and practical applications. Some of these compounds cannot be characterized by mass spectrometry. Here, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used for the characterization of tetrathiofulvalenes. The samples could be easily desorbed and ionized to form singly charged ions, and mass spectra with isotopic resolution readily obtained. The mass spectrometric results for 26 compounds have shown that MALDI-TOF is more effective and convenient than other mass spectrometry methods, and resolves the problem of mass spectrometric characterization of tetrathiofulvalene compounds.

Peroxisome proliferator-activated receptors and hepatic stellate cell activation

The present study examined the roles of peroxisome proliferator-activated receptors (PPAR) in activation of hepatic stellate cells (HSC), a pivotal event in liver fibrogenesis. RNase protection assay detected mRNA for PPARgamma1 but not that for the adipocyte-specific gamma2 isoform in HSC isolated from sham-operated rats, whereas the transcripts for neither isoforms were detectable in HSC from cholestatic liver fibrosis induced by bile duct ligation (BDL). Semi-quantitative reverse transcriptase-polymerase chain reaction confirmed a 70% reduction in PPARgamma mRNA level in HSC from BDL. Nuclear extracts from BDL cells showed an expected diminution of binding to PPAR-responsive element, whereas NF-kappaB and AP-1 binding were increased. Treatment of cultured-activated HSC with ligands for PPARgamma (10 microm 15-deoxy-Delta(12,14)-PGJ(2) (15dPGJ(2)); 0.1 approximately 10 microm BRL49653) inhibited DNA and collagen synthesis without affecting the cell viability. Suppression of HSC collagen by 15dPGJ(2) was abrogated 70% by the concomitant treatment with a PPARgamma antagonist (GW9662). HSC DNA and collagen synthesis were inhibited by WY14643 at the concentrations known to activate both PPARalpha and gamma (>100 microm) but not at those that only activate PPARalpha (<10 microm) or by a synthetic PPARalpha-selective agonist (GW9578). 15dPGJ(2) reduced alpha1(I) procollagen, smooth muscle alpha-actin, and monocyte chemotactic protein-1 mRNA levels while inducing matrix metalloproteinase-3 and CD36. 15dPGJ(2) and BRL49653 inhibited alpha1(I) procollagen promoter activity. Tumor necrosis factor alpha (10 ng/ml) reduced PPARgamma mRNA, and this effect was prevented by the treatment with 15dPGJ(2). These results demonstrate that HSC activation is associated with the reductions in PPARgamma expression and PPAR-responsive element binding in vivo and is reversed by the treatment with PPARgamma ligands in vitro. These findings implicate diminished PPARgamma signaling in molecular mechanisms underlying activation of HSC in liver fibrogenesis and the potential therapeutic value of PPARgamma ligands for liver fibrosis.

Functional cooperation between T helper cell determinants

The immune response to T helper (Th) cell determinants of a variety of antigens is often poor and limits severely the potential efficacy of current therapeutic measures through vaccination. Here, we report that an immunologically silent tumor determinant can be rendered immunogenic if linked with a dominant determinant of a parasite antigen, suggesting the existence of functional Th-Th cooperation in vivo. This phenomenon could be mimicked in part by signaling either through CD40 to the antigen-presenting cells or through OX40 to the tumor-determinant reactive T cells, with maximal effects obtained by combined anti-CD40 and anti-OX40 treatment in vivo. The data suggest that CD4 T cells reactive with a dominant determinant provide help to other CD4 T cells through up-regulating the costimulatory ability of antigen-presenting cells, in much the same way as help for CD8 cells. CD4 help for CD4 T cells represents a new immunological principle and offers new practical solutions for vaccine therapy against cancer and other diseases in which antigenic help is limiting.

Peroxisome proliferator-activated receptors and hepatic stellate cell activation

The present study examined the roles of peroxisome proliferator-activated receptors (PPAR) in activation of hepatic stellate cells (HSC), a pivotal event in liver fibrogenesis. RNase protection assay detected mRNA for PPARgamma1 but not that for the adipocyte-specific gamma2 isoform in HSC isolated from sham-operated rats, whereas the transcripts for neither isoforms were detectable in HSC from cholestatic liver fibrosis induced by bile duct ligation (BDL). Semi-quantitative reverse transcriptase-polymerase chain reaction confirmed a 70% reduction in PPARgamma mRNA level in HSC from BDL. Nuclear extracts from BDL cells showed an expected diminution of binding to PPAR-responsive element, whereas NF-kappaB and AP-1 binding were increased. Treatment of cultured-activated HSC with ligands for PPARgamma (10 microm 15-deoxy-Delta(12,14)-PGJ(2) (15dPGJ(2)); 0.1 approximately 10 microm BRL49653) inhibited DNA and collagen synthesis without affecting the cell viability. Suppression of HSC collagen by 15dPGJ(2) was abrogated 70% by the concomitant treatment with a PPARgamma antagonist (GW9662). HSC DNA and collagen synthesis were inhibited by WY14643 at the concentrations known to activate both PPARalpha and gamma (>100 microm) but not at those that only activate PPARalpha (<10 microm) or by a synthetic PPARalpha-selective agonist (GW9578). 15dPGJ(2) reduced alpha1(I) procollagen, smooth muscle alpha-actin, and monocyte chemotactic protein-1 mRNA levels while inducing matrix metalloproteinase-3 and CD36. 15dPGJ(2) and BRL49653 inhibited alpha1(I) procollagen promoter activity. Tumor necrosis factor alpha (10 ng/ml) reduced PPARgamma mRNA, and this effect was prevented by the treatment with 15dPGJ(2). These results demonstrate that HSC activation is associated with the reductions in PPARgamma expression and PPAR-responsive element binding in vivo and is reversed by the treatment with PPARgamma ligands in vitro. These findings implicate diminished PPARgamma signaling in molecular mechanisms underlying activation of HSC in liver fibrogenesis and the potential therapeutic value of PPARgamma ligands for liver fibrosis.

Neuronal hypertrophy in acute appendicitis

OBJECTIVE

The pathogenesis of appendicitis remains poorly understood. However, there is increasing evidence of involvement of the enteric nervous system in immune regulation and in inflammatory responses. This study was set up to characterize the status of the enteric nervous system in normal and in inflamed appendixes.

METHODS

S100- and 2',2'-cyclic nucleotide 3' phosphodiesterase-positive Schwann cells, synaptophysin, and neuron-specific, enolase-positive nerve fibers and tryptase-positive mast cells were evaluated with immunohistochemical staining in surgically resected appendixes from 20 children with histologically proven acute appendicitis (HA), 10 histologically normal appendixes (HN) from patients with a clinical diagnosis of appendicitis, and 10 normal appendixes from patients undergoing elective abdominal surgery. Immunostained sections were subjected to quantitative image analysis. The number and size of ganglia and the number of nerve fibers, Schwann cells, and mast cells in each tissue compartment was quantitatively or semiquantitatively measured.

RESULTS

Increased numbers of fibers, Schwann cells, and enlarged ganglia, widely distributed in the muscularis externa and submucosa, were seen in all HA appendixes and in 4 of 10 HN appendixes. The number and size of ganglia in muscularis externa and in the submucosa of appendixes with HA were significantly greater compared with those in control appendixes (P <.001). A significantly increased number of individually stained nerve fibers and Schwann cells (P <.05) were present in the muscularis externa in HA appendixes compared with control appendixes. Significantly increased numbers of tryptase-positive mast cells (P <.05) were present in the submucosa, muscularis, and especially in the lamina propria in HA specimens, compared with that of control tissue.

CONCLUSIONS

The significant increase in neural components and mast cells in acute appendicitis is unlikely to develop during a single acute inflammatory episode. This suggests an underlying chronic abnormality as a secondary reaction to repeated bouts of inflammation, obstruction, or both. These results challenge our current understanding of the pathophysiological processes that give rise to acute appendicitis.