Effect of 2.1 MPa and 4.1 MPa H2O2 exposure on auditory brain stem evoked potential in mice

Brain auditory evoked potential (BAEP) in mice exposed to hyperbaric H2O2 pressure was monitored to reveal the correlation between altered synaptic transmission and hydrogen narcosis or isobaric HPNS. Inter peak latencies and wave amplitudes were selected as indices of assessment. The animals were exposed either to He-O2 or H2-O2 at 2.1 MPa and 4.1 MPa. Results showed that synaptic transmission was inhibited to various extents. The inhibition was partly due to the narcotic effect of hydrogen, which was added to the effect caused by hydrostatic pressure. On the other hand, asymmetrical reaction of each segment in the neuro-network might be responsible for the occurrence of HPNS.

Assessment of PCBs and PCDD/Fs along the Chinese Bohai Sea coastline using mollusks as bioindicators

Mollusk samples such as bivalves and gastropods were collected from eight sampling sites along Bohai Sea coastline from northeastern China. The samples were analyzed for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) to elucidate bioaccumulation of persistent organic pollutants in benthon. Residue levels of sigmaPCBs and sigmaPCDD/Fs were in the ranges of 66.1 to 583.6 ng/g and 0.9 to 15317 pg/g on a lipid-weight basis, respectively, The pollution source was identified using principal component analysis (PCA) in some coastal areas. It indicated that the typical pollution sources were characterized by PCB3, which was one Chinese technical product of PCBs. PCA also revealed the similarity patterns of PCBs between identical species collected from the different sites. The higher gastropod PCB concentrations were related to a former capacitor factory and the paint factories in some coastal areas, but this was not the case with the bivalves. The results of this study suggest that some gastropod species may be a potential bioindicator or "sentinel" organism for marine PCBs monitoring.

Behavior pattern (innate action) of individuals in fish schools generating efficient collective evasion from predation

The schooling of fishes is one typical animal social behavior. One primary function of fish school is to protect members when attacked by predators. One main way that the school reduces the predator's chance of making a successful kill is to confuse the predator as it makes its strike. This may be accomplished by collective evasion behaviors organized through integration of motions of individual fish made based on their innate actions (behavior patterns). In order to investigate what kind of behavior pattern of individuals can generate the efficient collective evasion of a school, we present a model of evasion behavior pattern which consists of three component behavior patterns, schooling, cooperative escape, and selfish escape behavior patterns and the rule for choice of one among them with proper timing. Each fish determines its movement direction taking into account simultaneously three kinds of elemental motions, mimicking its neighbors, avoiding collisions with its nearest neighbors, and escaping from an approaching predator. The weights of three elemental motions are changed depending on which component behavior pattern the fish carries out. The values of the weights for three component behavior patterns can be definitively determined under the condition that the collective evasion of the school becomes the most efficient, that is, the probability that any member is eaten by the predator becomes minimum.

Phonon-assisted excitonic recombination channels observed in DNA-wrapped carbon nanotubes using photoluminescence spectroscopy

By using a sample of DNA-wrapped single-wall carbon nanotubes strongly enriched in the (6,5) nanotube, photoluminescence emissions observed at special excitation energy values were identified with specific mechanisms of phonon-assisted excitonic absorption and recombination processes associated with (6,5) nanotubes, including one-phonon, two-phonon, and some continuous-luminescence processes. Such detailed processes are not separately identified in three-dimensional semiconducting materials. A general theoretical framework is presented to interpret the experimentally observed phonon-assisted processes in terms of excitonic states.

Resonance Raman spectroscopy characterization of single-wall carbon nanotube separation by their metallicity and diameter

Several techniques were recently reported for the bulk separation of metallic (M) and semiconducting (S) single wall carbon nanotubes (SWNTs), using optical absorption and resonance Raman spectroscopy (RRS) as a proof of the separation. In the present work, we develop a method for the quantitative evaluation of the M to S separation ratio, and also for the SWNT diameter selectivity of the separation process, based on RRS. The relative changes in the integrated intensities of the radial-breathing mode (RBM) features, with respect to the starting material, yield the diameter probability distribution functions for M and S SWNTs in the separated fractions, accounting for the different resonance conditions of individual SWNTs, while the diameter distribution of the starting material is obtained following the fitting procedure developed by Kuzmany and coworkers. Features other than the RBM are generally less effective for characterization of the separation process for SWNTs.

Dynamics of {beta}-amyloid reductions in brain, cerebrospinal fluid, and plasma of {beta}-amyloid precursor protein transgenic mice treated with a {gamma}-secretase inhibitor

gamma-Secretase inhibitors are one promising approach to the development of a therapeutic for Alzheimer's disease (AD). gamma-Secretase inhibitors reduce brain beta-amyloid peptide (Abeta), which is believed to be a major contributor in the etiology of AD. Transgenic mice overexpressing the human beta-amyloid precursor protein (APP) are valuable models to examine the dynamics of Abeta changes with gamma-secretase inhibitors in plaque-free and plaque-bearing animals. BMS-299897 2-[(1R)-1-[[(4-chlorophenyl)sulfony](2,5-difluorophenyl)amino]ethyl]-5-fluorobenzenepropanoic acid, a gamma-secretase inhibitor, showed dose- and time dependent reductions of Abeta in brain, cerebrospinal fluid (CSF), and plasma in young transgenic mice, with a significant correlation between brain and CSF Abeta levels. Because CSF and brain interstitial fluid are distinct compartments in composition and location, this correlation could not be assumed. In contrast, aged transgenic mice with large accumulations of Abeta in plaques showed reductions in CSF Abeta in the absence of measurable changes in plaque Abeta in the brain after up to 2 weeks of treatment. Hence, CSF Abeta levels were a valuable measure of gamma-secretase activity in the central nervous system in either the presence or absence of plaques. Transgenic mice were also used to examine potential side effects due to Notch inhibition. BMS-299897 was 15-fold more effective at preventing the cleavage of APP than of Notch in vitro. No changes in the maturation of CD8(+) thymocytes or of intestinal goblet cells were observed in mice treated with BMS-299897, showing that it is possible for gamma-secretase inhibitors to reduce brain Abeta without causing Notch-mediated toxicity.

Conch shell structure and its effect on mechanical behaviors

The shell of pink conch is a kind of natural well-designed composite with excellent mechanical properties, which provides us information for material design. In this paper the microstructures of pink conch shell are characterized by using SEM and TEM. The microscopic analysis indicates that the pink conch shell is with crossed-lamellar microstructure and the angle between two second-order lamellae is 70-90 degrees. The cracking and fracture morphologies indicate that the crack deflection, bridge and fiber pullout are the main toughening mechanisms. Bamboo lamellae are employed to make the simple bio-mimetic model materials. In the model material the rotated angle between the fibers of each glued lamella varies from 0 degrees to 90 degrees. Three-point-bending is employed to test the properties of models material, such as the elastic modulus, the flexural strength and the fracture strain energy density. It is found that the fracture strain energy density of the specimens with the rotated angle between the fibers of the layers about 60 degrees exhibits the maximum value, which is close to the angle of the two second-order lamellae of the conch shell.

Hydromorphone metabolites: isolation and identification from pooled urine samples of a cancer patient

1. Hydromorphone-3-glucuronide, dihydromorphine, dihydroisomorphine, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide were isolated from a cancer patient's urine and identified as metabolites of hydromorphone by comparison with synthetic standards using LC/MS/MS with gradient elution. 2. The relative urinary recovery of dihydroisomorphine-3-glucuronide was estimated to be 17-fold higher than previously reported. 3. Three new metabolites, including hydromorphone-3-sulphate, norhydromorphone and nordihydroisomorphine, were tentatively identified.

LC-MS-MS analysis of hydromorphone and hydromorphone metabolites with application to a pharmacokinetic study in the male Sprague-Dawley rat

1. A high performance liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS) assay was developed for the analysis of hydromorphone and its metabolites, namely dihydromorphine, dihydroisomorphine, hydromorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide, in rat plasma samples. 2. Analytes were extracted by solid-phase extraction using C2 cartridges. The extraction recoveries were > 76% for all analytes. Both intra- and interassay variabilities were < or = 12%. Using a plasma sample size of 100 microl, the limits of detection were 7.0 nmol(-1) (2.0 ng ml(-1)) for hydromorphone, dihydromorphine and dihydroisomorphine and 11 nmol l(-1) (5.0 ng ml l(-1)) for hydrormorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorhine-3-glucuronide at a signal-to-noise ratio = 3. 3. The present assay was applied to a pharmacokinetic study in rat after intraperitoneal administration of hydromorphone.

Enzymatic Synthesis and Analysis of Large-Ring Cyclodextrins

Large-ring cyclodextrins (LR-CD) are cyclic α-1,4-glucans composed of nine to more than several hundred glucopyranose units. Cyclodextrins are able to form highly specific inclusion complexes with a wide range of guest molecules thereby modifying their physicochemical properties. Only in the past 10 years, LR-CD with a degree of polymerization between 9 and 32 have been isolated and characterized. The structures of these LR-CD show novel features distinct from those of the extensively studied α- β-, and γ-CD composed of six, seven, and eight glucopyranose units, respectively. Recent work on the enzymatic synthesis of LR-CD has confirmed the ability of different 4-α-glucanotransferases to form large cyclic α-1,4-glucans from amylose and amylopectin, depending on the specificity of the enzyme used and on the substrate and reaction conditions chosen. The potential of LR-CD for specific host-guest interactions and corresponding applications has been demonstrated.

CD4+ T cell-independent vaccination against Pneumocystis carinii in mice

Host defenses are profoundly compromised in HIV-infected hosts due to progressive depletion of CD4+ T lymphocytes. Moreover, deficient CD4+ T lymphocytes impair vaccination approaches to prevent opportunistic infection. Therefore, we investigated a CD4+ T cell-independent vaccine approach to a prototypic AIDS-defining infection, Pneumocystis carinii (PC) pneumonia. Here, we demonstrate that bone marrow-derived dendritic cells (DCs) expressing the murine CD40 ligand, when pulsed ex vivo by PC antigen, elicited significant titers of anti-PC IgG in CD4-deficient mice. Vaccinated animals demonstrated significant protection from PC infection, and this protection was the result of an effective humoral response, since adoptive transfer of CD4-depleted splenocytes or serum conferred this protection to CD4-deficient mice. Western blot analysis of PC antigen revealed that DC-vaccinated, CD4-deficient mice predominantly reacted to a 55-kDa PC antigen. These studies show promise for advances in CD4-independent vaccination against HIV-related pathogens.

[Spectroscopic differentiation between normal bronchial and lung cancer tissues by laser-induced fluorescence (LIF) with intravenous injection of hematoporphyrin monomethyl ether (HMME)]

BACKGROUND

To study the feasibility of laser-induced fluorescence ( LIF) spectroscopy with intravenous injection of a new agent, hematoporphyrin monomethyl ether (HMME) , in the diagnosis of lung cancer.

METHODS

Fifteen patients with lung cancer were administrated HMME 2. 5 mg/ kg intravenously three hours before lobectomy. Surgical specimens were collected for examination of LIF spectrum. TheLIF spectra of normal bronchial and lung cancer tissues were measured with a detecting system which consists of an YAG laser ( wavelength 355 nm) and an optical multichannel analyzer ( OMA) . The patholog ical examination was performed in each specimen.

RESULTS

The fluorescence intensity of the lung cancer tissues ( 31 446±5 017) was much lower than that of the normal bronchial tissues ( 75 430±8 908) ( P < 0. 001) . There was a flat spectrum in the normal bronchial tissues at the wavelength from 580 to 600 nm ( I580nm / I600nm = 1. 081 ±0. 090) , but the cancer tissue spectrum showed a smoothly descending profile ( I580nm/ I600nm = 1. 260±0. 157) . A remarkable characteristic peak ( drug peak) located at the 623. 4 nm±1. 6 nm in the lung cancer spectrum. Using the criterion of I580nm/ I600nm , the sensitivity, specificity, and accuracy of the diagnosis for lung cancer were 80. 0%, 73. 9%, and 76. 7%, respectively , and were 95. 0%, 91. 3% and 93. 0% respectively according to the criterion of the slope of the drug peak.

CONCLUSIONS

The LIF spectroscopy following intravenous injection of the new photosensitiser HMME can differentiate lung cancer from normal bronchus and can increase the sensitivity, specificity and the accuracy comparing to the laser-induced auto fluorescence in the diagnosis of lung cancer.

Chromophore attachment to biliproteins: specificity of PecE/PecF, a lyase-isomerase for the photoactive 3(1)-cys-alpha 84-phycoviolobilin chromophore of phycoerythrocyanin

PecE and PecF, the products of two phycoerythrocyanin lyase genes (pecE and pecF) of Mastigocladus laminosus (Fischerella), catalyze two reactions: (1) the regiospecific addition of phycocyanobilin (PCB) to Cys-alpha 84 of the phycoerythrocyanin alpha-subunit (PecA), and (2) the Delta 4-->Delta 2 isomerization of the PCB to the phycoviolobilin (PVB)-chromophore [Zhao et al. (2000) FEBS Lett. 469, 9-13]. The alpha-apoprotein (PecA) as well PecE and PecF were overexpressed from two strains of M. laminosus, with and without His-tags. The products of the spontaneous addition of PCB to PecA, and that of the reaction catalyzed by PecE/F, were characterized by their photochemistry and by absorption, fluorescence, circular dichroism of the four states obtained by irradiation with light (15-Z/E isomers of the chromophore) and/or modification of Cys-alpha 98/99 with thiol-directed reagents. The spontaneous addition leads to a 3(1)-Cys-PCB adduct, which is characteristic of allophycocyanins and phycocyanins, while the addition catalyzed by PecE and PecF leads to a 3(1)-Cys-PVB adduct which after purification was identical to alpha-PEC. The specificity and kinetics of the chromophore additions were investigated with respect to the structure of the bilin substrate: The 3-ethylidene-bilins, viz., PCB, its 18-vinyl analogue phytochromobilin, phycoerythrobilin and its dimethylester, react spontaneously to yield the conventional addition products (3-H, 3(1)-Cys), while the 3-vinyl-substituted bilins, viz., bilirubin and biliverdin, were inactive. Only phycocyanobilin and phytochromobilin are substrates to the addition-isomerization reaction catalyzed by PecE/F. The slow spontaneous addition of phycoerythrobilin is not influenced, and there is in particular no catalyzed isomerization to urobilin.

The in vivo role of p38 MAP kinases in cardiac remodeling and restrictive cardiomyopathy

Stress-induced mitogen-activated protein kinase (MAP) p38 is activated in various forms of heart failure, yet its effects on the intact heart remain to be established. Targeted activation of p38 MAP kinase in ventricular myocytes was achieved in vivo by using a gene-switch transgenic strategy with activated mutants of upstream kinases MKK3bE and MKK6bE. Transgene expression resulted in significant induction of p38 kinase activity and premature death at 7-9 weeks. Both groups of transgenic hearts exhibited marked interstitial fibrosis and expression of fetal marker genes characteristic of cardiac failure, but no significant hypertrophy at the organ level. Echocardiographic and pressure-volume analyses revealed a similar extent of systolic contractile depression and restrictive diastolic abnormalities related to markedly increased passive chamber stiffness. However, MKK3bE-expressing hearts had increased end-systolic chamber volumes and a thinned ventricular wall, associated with heterogeneous myocyte atrophy, whereas MKK6bE hearts had reduced end-diastolic ventricular cavity size, a modest increase in myocyte size, and no significant myocyte atrophy. These data provide in vivo evidence for a negative inotropic and restrictive diastolic effect from p38 MAP kinase activation in ventricular myocytes and reveal specific roles of p38 pathway in the development of ventricular end-systolic remodeling.

Contribution of vascular endothelial growth factor in the neovascularization process during the pathogenesis of herpetic stromal keratitis

This report analyzes the role of vascular endothelial growth factor (VEGF)-induced angiogenesis in the immunoinflammatory lesion stromal keratitis induced by ocular infection with herpes simplex virus (HSV). Our results show that infection with replication-competent, but not mutant, viruses results in the expression of VEGF mRNA and protein in the cornea. This a rapid event, with VEGF mRNA detectable by 12 h postinfection (p.i.) and proteins detectable by 24 h p.i. VEGF production occurred both in the virus-infected corneal epithelium and in the underlying stroma, in which viral antigens were undetectable. In the stroma, VEGF was produced by inflammatory cells; these initially were predominantly polymorphonuclear leukocytes (PMN), but at later time points both PMN and macrophage-like cells were VEGF producers. In the epithelium, the major site of VEGF-expressing cells in early infection, the infected cells themselves were usually negative for VEGF. Similarly, in vitro infection studies indicated that the cells which produced VEGF were not those which expressed virus. Attesting to the possible role of VEGF-induced angiogenesis in the pathogenesis of herpetic stromal keratitis were experiments showing that VEGF inhibition with mFlt(1-3)-immunoglobulin G diminished angiogenesis and the severity of lesions after HSV infection. These observations are the first to evaluate VEGF-induced angiogenesis in the pathogenesis of stromal keratitis. Our results indicate that the control of angiogenesis represents a useful adjunct to therapy of herpetic ocular disease, an important cause of human blindness.

Control of stromal keratitis by inhibition of neovascularization

Stromal keratitis resulting from ocular infection with herpes simplex virus is a common cause of blindness. This report investigates the role of neovascularization in the pathogenesis of stromal keratitis by measuring the outcome of treatment with the potent anti-angiogenesis cytokine endothelial monocyte-activating polypeptide II (EMAP II). We show that systemic and topical administration of EMAP II from the outset of infection resulted in markedly diminished levels of herpes simplex virus-induced angiogenesis and significantly reduced the severity of stromal keratitis lesions. EMAP II treatment had no demonstrable pro-inflammatory or toxic effects and failed to express antiviral activity. The mechanism of action of EMAP II was shown to proceed by causing apoptosis in vascular endothelial cells. Our data document for the first time the essential role of angiogenesis in the pathogenesis of stromal keratitis and also indicate that the therapy of herpetic stromal keratitis could benefit by procedures that diminish angiogenesis.

Bystander activation involving T lymphocytes in herpetic stromal keratitis

Herpes simplex virus infection of mouse corneas can lead to the development of an immunopathological lesion, termed herpetic stromal keratitis (HSK). Such lesions also occur in TCR-transgenic mice backcrossed to SCID (TgSCID) that are unable to mount detectable HSV-specific immune responses. The present study demonstrates that lesion expression in such mice depends on continuous viral replication, whereas in immunocompetent mice, lesions occurred even if virus replication was terminated at 4 days after infection. The continuous replication in TgSCID mice was considered necessary to produce an activating stimulus to CD4(+) T cells that invade the cornea. Lesions in TgSCID were resistant to control by cyclosporin A, but were inhibited by treatment with rapamycin. This result was interpreted to indicate that T cell activation involved a non-TCR-mediated cytokine-driven bystander mechanism. Bystander activation was also shown to play a role in HSK lesions in immunocompetent mice. Accordingly, in immunocompetent DO11.10 mice, lesions were dominated by KJ1.26(+) OVA-specific CD4(+) T cells that were unreactive with HSV. In addition, KJ1.26(+) HSV nonimmune cells parked in ocularly infected BALB/c mice were demonstrable in HSK lesions. These results provide insight for the choice of new strategies to manage HSK, an important cause of human blindness.

The BPAG1 locus: Alternative splicing produces multiple isoforms with distinct cytoskeletal linker domains, including predominant isoforms in neurons and muscles

Bullous pemphigoid antigen 1 (BPAG1) is a member of the plakin family with cytoskeletal linker properties. Mutations in BPAG1 cause sensory neuron degeneration and skin fragility in mice. We have analyzed the BPAG1 locus in detail and found that it encodes different interaction domains that are combined in tissue-specific manners. These domains include an actin-binding domain (ABD), a plakin domain, a coiled coil (CC) rod domain, two different potential intermediate filament-binding domains (IFBDs), a spectrin repeat (SR)-containing rod domain, and a microtubule-binding domain (MTBD). There are at least three major forms of BPAG1: BPAG1-e (302 kD), BPAG1-a (615 kD), and BPAG1-b (834 kD). BPAG1-e has been described previously and consists of the plakin domain, the CC rod domain, and the first IFBD. It is the primary epidermal BPAG1 isoform, and its absence that is the likely cause of skin fragility in mutant mice. BPAG1-a is the major isoform in the nervous system and a homologue of the microtubule actin cross-linking factor, MACF. BPAG1-a is composed of the ABD, the plakin domain, the SR-containing rod domain, and the MTBD. The absence of BPAG1-a is the likely cause of sensory neurodegeneration in mutant mice. BPAG1-b is highly expressed in muscles, and has extra exons encoding a second IFBD between the plakin and SR-containing rod domains of BPAG1-a.

[Effect of the Purariae-isofiavones on atrophic nasal mucosas in ovariectomized rats]

OBJECTIVE

To study the effect of Purariae-isoflavone on atrophic nasal mucosas in ovariectomized rats.

METHOD

60 rats were divided into four groups randomly, every group with 15 rats. The first group was studied as normal control group. Rats of the second group were ovariectomized and not given any treatment. Rats of the third group were given Weinian by gastrogavage from 30 days after being ovariectomized to being killed. Rats of the forth group were given purariae isoflavone by gastrogavage from 30 days after operation to being killed. Level of Estrodiol (E2) of every rat was measured. Morphological changes of the nasal mucosas were observed by light-microscopy and electron-microscopy.

RESULT

30 days after being ovariectomized, atrophic nasal mucosas occured, and average E2 level was lower significantly than that of control group (P < 0.05). Atrophic mucosas recovered after being treated with Weinian or Purariae isoflavone. E2 level of the third group was lower significantly than that of the first group and the second group (P < 0.05). E2 level of the forth group recovered (P > 0.05).

CONCLUSION

Purariae-isoflavone have effects on treating the atrophic nasal mucosas and recovering E2 level in ovariectomized rats.

DNA microarray-mediated transcriptional profiling of the Escherichia coli response to hydrogen peroxide

The genome-wide transcription profile of Escherichia coli cells treated with hydrogen peroxide was examined with a DNA microarray composed of 4,169 E. coli open reading frames. By measuring gene expression in isogenic wild-type and oxyR deletion strains, we confirmed that the peroxide response regulator OxyR activates most of the highly hydrogen peroxide-inducible genes. The DNA microarray measurements allowed the identification of several new OxyR-activated genes, including the hemH heme biosynthetic gene; the six-gene suf operon, which may participate in Fe-S cluster assembly or repair; and four genes of unknown function. We also identified several genes, including uxuA, encoding mannonate hydrolase, whose expression might be repressed by OxyR, since their expression was elevated in the DeltaoxyR mutant strain. In addition, the induction of some genes was found to be OxyR independent, indicating the existence of other peroxide sensors and regulators in E. coli. For example, the isc operon, which specifies Fe-S cluster formation and repair activities, was induced by hydrogen peroxide in strains lacking either OxyR or the superoxide response regulators SoxRS. These results expand our understanding of the oxidative stress response and raise interesting questions regarding the nature of other regulators that modulate gene expression in response to hydrogen peroxide.

Computation-directed identification of OxyR DNA binding sites in Escherichia coli

A computational search was carried out to identify additional targets for the Escherichia coli OxyR transcription factor. This approach predicted OxyR binding sites upstream of dsbG, encoding a periplasmic disulfide bond chaperone-isomerase; upstream of fhuF, encoding a protein required for iron uptake; and within yfdI. DNase I footprinting assays confirmed that oxidized OxyR bound to the predicted site centered 54 bp upstream of the dsbG gene and 238 bp upstream of a known OxyR binding site in the promoter region of the divergently transcribed ahpC gene. Although the new binding site was near dsbG, Northern blotting and primer extension assays showed that OxyR binding to the dsbG-proximal site led to the induction of a second ahpCF transcript, while OxyR binding to the ahpCF-proximal site leads to the induction of both dsbG and ahpC transcripts. Oxidized OxyR binding to the predicted site centered 40 bp upstream of the fhuF gene was confirmed by DNase I footprinting, but these assays further revealed a second higher-affinity site in the fhuF promoter. Interestingly, the two OxyR sites in the fhuF promoter overlapped with two regions bound by the Fur repressor. Expression analysis revealed that fhuF was repressed by hydrogen peroxide in an OxyR-dependent manner. Finally, DNase I footprinting experiments showed OxyR binding to the site predicted to be within the coding sequence of yfdI. These results demonstrate the versatile modes of regulation by OxyR and illustrate the need to learn more about the ensembles of binding sites and transcripts in the E. coli genome.

[Determination and significance of serum markers for fibrosis in patients with chronic hepatitis]

OBJECTIVE

To find the relationship between serum levels of hyaluronic acid (HA), type III procollagen (PC III), laminin (LN), type IV collagen (IV-C) and hepatic fibrosis as well as to determine their value in clinical practice.

METHODS

2600 serum samples from chronic hepatitis patients were tested with RIA for fibrosis indexes assays including HA, PC III, LN and IV-C. 280 of the patients with serum samples taken had liver biopsy performed and the biopsy material was examine pathomorphologically. Fibrosis indexes were compared according to inflammation grade, fibrosis stage and chronic hepatitis degree.

RESULTS

In the 2600 serum samples from chronic hepatitis patients, fibrosis indexes (including HA, PC III, LN and IV-C) had significant correlation with inflammation grade, fibrosis stage and the degree of chronic hepatitis (P < 0.01). The relating indexes to HA were 0.544, 0.548, 0.468 respectively, to PC III 0.495, 0.424, 0.335 respectively, to LN 0.214, 0.204, 0.184 and to IV-C were 0.464, 0.404, 0.412 respectively.

CONCLUSION

Serum fibrosis indexes are fairly well correlated with the inflammation grade, fibrosis stage and the degree of chronic hepatitis. However, as diagnostic markers, they must be combined with liver function, ultrasonography and clinical features.

Microevolutionary analysis of the nematode genus Pristionchus suggests a recent evolution of redundant developmental mechanisms during vulva formation

To identify the mechanisms by which molecular variation is introduced into developmental systems, microevolutionary approaches to evolutionary developmental biology have to be taken. Here, we describe the molecular and developmental characterization of laboratory strains of the nematode genus Pristionchus, which lays a foundation for a microevolutionary analysis of vulva development. We describe 13 laboratory strains of the Pristionchus genus that are derived from natural isolates from around the world. Mating experiments and ITS sequence analysis indicated that these 13 strains represent four different species: the gonochoristic species P. Iheritieriand three hermaphroditic species, P. pacificus, P. maupasi, and an as yet undescribed species Pristionchus sp., respectively. P. pacificus is represented by five different strains isolated from California, Washington, Hawaii, Ontario, and Poland. Developmental differences during vulva formation are observed between strains from different species but also between strains of P. pacificus, like the strains from California and Poland. In particular, redundant developmental mechanisms present during vulva formation in P. pacificus var. California are absent in other strains. Amplified restriction fragment length polymorphism (AFLP) analyses of the P. pacificus strains revealed that the American strains are highly polymorphic. In contrast, the developmentally distinct strain from Poland is identical to the Californian strain, suggesting that the developmental differences rely on a small number of changes in developmental control genes rather than the accumulation of changes at multiple loci.

[Therapeutic potential of recombinant adenovirus expressing p53 in hepatocellular carcinoma cell lines]

OBJECTIVE

To investigate the effects of the recombinant adenoviral vector Ad-p53 on the biological behavior of hepatocellular carcinoma (HCC) cells in vitro and in vivo.

METHODS

With recombinant adenoviral vector expressing WT-p53 (Ad-p53), p53 gene was transfected into the HCC cell line, PLC/PRF/5. The cytotoxicities of Ad-p53 to cells were measured by MTT assay. Cell growth properties and cell cycle patterns were assessed with flow cytometry. The animal model was developed by injecting HCC cells into the dorsum of nude mice. Ad-p53 was injected intratumorally. The animals were killed, and then excised tumors were weighed and analyzed for p53 and p21 protein expression using western blot assay.

RESULTS

The introduction of exogenous wild-type p53 resulted in the inhibition of cell growth, high G2/M ratio and cell apoptosis, and low S ratio in PLC/PRF/5. The expression of both p53 and p21 proteins was upregulated in the cells.

CONCLUSIONS

Replication-deficient adenoviral vector expressing WT-p53 may be useful for gene therapy of HCC.

Herpes simplex virus-induced keratitis: evaluation of the role of molecular mimicry in lesion pathogenesis

Viruses are suspected but usually unproven triggering factors in autoimmunity. One favored mechanism to explain the role of viruses in the genesis of autoimmunity is molecular mimicry. An immunoinflammatory blinding lesion called herpetic stromal keratitis (HSK) that follows ocular infection with herpes simplex virus (HSV) is suggested to result from a CD4(+) T-cell response to a UL6 peptide of HSV that cross-reacts with a corneal autopeptide shared with the immunoglobulin G2a(b) (IgG2a(b)) isotype. The present report reevaluates the molecular mimicry hypothesis to explain HSK pathogenesis. Our results failed to reveal cross-reactivity between the UL6 and IgG2a(b) peptides or between peptide reactive T cells and HSV antigens. More importantly, animals infected with HSV failed to develop responses that reacted with either peptide, and infection with a recombinant vaccinia UL6 vector failed to cause HSK, in spite of generating UL6 reactivity. Other lines of evidence also failed to support the molecular mimicry hypothesis, such as the failure to affect HSK severity upon tolerization of susceptible BALB/c and B-cell-deficient mice with IgG2a(b) or UL6 peptides. An additional study system revealed that HSK could be induced in mouse strains, such as the OT2 x RAG1(-/-) mice (T cell receptor transgenic recognizing OVA(323-339)) that were unable to produce CD4(+) T-cell responses to any detectable HSV antigens. Our results cast doubt on the molecular mimicry hypothesis as an explanation for the pathogenesis of HSK and indicate that if autoimmunity is involved its likely proceeds via a bystander activation mechanism.

Formation of a GNRA tetraloop in P5abc can disrupt an interdomain interaction in the Tetrahymena group I ribozyme

The secondary structure of a truncated P5abc subdomain (tP5abc, a 56-nucleotide RNA) of the Tetrahymena thermophila group I intron ribozyme changes when its tertiary structure forms. We have now used heteronuclear NMR spectroscopy to determine its conformation in solution. The tP5abc RNA that contains only secondary structure is extended compared with the tertiary folded form; both forms coexist in slow chemical exchange (the interconversion rate constant is slower than 1 s(-1)) in the presence of magnesium. Kinetic experiments have shown that tertiary folding of the P5abc subdomain is one of the earliest folding transitions in the group I intron ribozyme, and that it leads to a metastable misfolded intermediate. Previous mutagenesis studies suggest that formation of the extended P5abc structure described here destabilize a misfolded intermediate. This study shows that the P5abc RNA subdomain containing a GNRA tetraloop in P5c (in contrast to the five-nucleotide loop P5c in the tertiary folded ribozyme) can disrupt the base-paired interdomain (P14) interaction between P5c and P2.

A bipotential precursor population for pancreas and liver within the embryonic endoderm

The pancreas emerges independently from dorsal and ventral domains of embryonic gut endoderm. Gene inactivation experiments in mice have identified factors required for dorsal pancreas development, but factors that initiate the ventral pancreas have remained elusive. In this study, we investigated the hypothesis that the emergence of the ventral pancreas is related to the emergence of the liver. We find that the liver and ventral pancreas are specified at the same time and in the same general domain of cells. Using embryo tissue explantation experiments, we find that the default fate of the ventral foregut endoderm is to activate the pancreas gene program. FGF signalling from the cardiac mesoderm diverts this endoderm to express genes for liver instead of those for pancreas. No evidence was found to indicate that the cell type choice for pancreas or liver involves a selection for growth or viability. Cardiac mesoderm or FGF induces the local expression of sonic hedgehog, which in turn is inhibitory to pancreas but not to liver. The bipotential precursor cell population for pancreas and liver in embryonic development and its fate selection by FGF has features that appear to be recapitulated in the adult pancreas and are reflected in the evolution of these organs.

Induction of arginases I and II in cornea during herpes simplex virus infection

Induction of inducible nitric oxide synthase (iNOS) following corneal infection with herpes simplex virus type-1 (HSV-1) generates nitric oxide (NO), an important player in the defense against viral infection. Changes in arginine metabolism during infection are not limited to effects of iNOS but can also involve arginases, which can modulate NO synthesis and produce ornithine for the generation of polyamines and proline. The latter are important molecules involved in tissue damage and repair during inflammation. In this study we determined the responses of arginase I and II in a murine model of HSV-1-induced stromal keratitis (HSK). In the cornea iNOS and arginase II mRNA were co-induced as the initial inflammation developed at 2 days postinfection (p.i.). As stromal keratitis progressed (days 8-15 p.i.) arginase I mRNA was induced tenfold, in contrast to a moderate decrease in arginase II and a loss of iNOS expression. These results suggest that elevated expression of arginase I and II in the cornea at late stages of ocular HSV-1 infection may play a role in lesion expression in HSK.

A simple and efficient method to transcribe RNAs with reduced 3' heterogeneity

Ribose C2' methoxy groups (-OCH3) on the penultimate nucleotide or the last two nucleotides of DNA templates can dramatically improve the quality of transcripts produced by T7 RNA polymerase. This strategy can be adapted to generate transcripts of varying lengths and will allow greater ease in purification of the products.

Dual modulation of cell survival and cell death by beta(2)-adrenergic signaling in adult mouse cardiac myocytes

The goal of this study was to determine whether beta(1)-adrenergic receptor (AR) and beta(2)-AR differ in regulating cardiomyocyte survival and apoptosis and, if so, to explore underlying mechanisms. One potential mechanism is that cardiac beta(2)-AR can activate both G(s) and G(i) proteins, whereas cardiac beta(1)-AR couples only to G(s). To avoid complicated crosstalk between beta-AR subtypes, we expressed beta(1)-AR or beta(2)-AR individually in adult beta(1)/beta(2)-AR double knockout mouse cardiac myocytes by using adenoviral gene transfer. Stimulation of beta(1)-AR, but not beta(2)-AR, markedly induced myocyte apoptosis, as indicated by increased terminal deoxynucleotidyltransferase-mediated UTP end labeling or Hoechst staining positive cells and DNA fragmentation. In contrast, beta(2)-AR (but not beta(1)-AR) stimulation elevated the activity of Akt, a powerful survival signal; this effect was fully abolished by inhibiting G(i), G(beta gamma), or phosphoinositide 3 kinase (PI3K) with pertussis toxin, beta ARK-ct (a peptide inhibitor of G(beta gamma)), or LY294002, respectively. This indicates that beta(2)-AR activates Akt via a G(i)-G(beta gamma)-PI3K pathway. More importantly, inhibition of the G(i)-G(beta gamma)-PI3K-Akt pathway converts beta(2)-AR signaling from survival to apoptotic. Thus, stimulation of a single class of receptors, beta(2)-ARs, elicits concurrent apoptotic and survival signals in cardiac myocytes. The survival effect appears to predominate and is mediated by the G(i)-G(beta gamma)-PI3K-Akt signaling pathway.