Effect of Escherichia coli Heat-labile Enterotoxin on the Myoelectric Activity of the Duodenum in Weaned Pigs

The objective of the present study was to elucidate the effect of subclinical doses of Escherichia coli heat-labile enterotoxin (LT) on the antro-duodenal myoelectric activities of weaned pigs. Twelve weaned pigs were surgically implanted with three pairs of electrodes on the antrum 3 cm before the pylorus, 5 and 20 cm after the pylorus on the duodenum, respectively. An infusion cannula was inserted into the duodenum between duodenal electrodes. Using a wireless telemetry recording system, an electromyography (EMG) tracing lasting at least 24 h was recorded as the control, then another 24-h EMG recording was performed with a bolus intraduodenal infusion of LT (0.1 and 0.5 microg/kg b.w.). After a 1- to 2-day break, a 5-fold higher dose of LT was administered using the same protocol. In the antrum, LT administration barely modified the EMG signal. However, in the duodenum it prolonged the duration of phase II and the migrating myoelectric complex (MMC) cycle when compared with the control. The number of duodenal MMC cycles was also significantly diminished. Moreover, the migrating velocity of phase III was increased. The migrating action potential complex (MAPC) was present both without and with LT, but occurred more frequently following LT administration. In conclusion, LT caused a dose-dependent, lagged alteration in the duodenal MMC in weaned pigs, involving a reduction of the MMC number by lengthening phase II, increased phase III migration velocity, and increased MAPC frequency. The disturbances did not, however, result in diarrhoea and may reflect the induction of a local protection mechanism of the gut to expel unwanted foreign content from the lumen of the upper gut.

c-Src induces phosphorylation and translocation of p47phox: role in superoxide generation by angiotensin II in human vascular smooth muscle cells

OBJECTIVE

The aim of this study was to determine molecular mechanisms whereby c-Src regulates angiotensin II (Ang II)-mediated NAD(P)H oxidase-derived *O2- in human vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS

VSMCs from human small arteries were studied. Ang II increased NAD(P)H oxidase-mediated generation of *O2- and H2O2 (P<0.01). PP2, c-Src inhibitor, attenuated these effects by 70% to 80%. Immunoprecipitation of p47phox, followed by immunoblotting with antiphosphoserine antibody, demonstrated a rapid increase (1.5- to 2-fold) in p47phox phosphorylation in Ang II-stimulated cells. This was associated with p47phox translocation from cytosol to membrane, as assessed by immunoblotting and immunofluorescence. PP2 abrogated these effects. Long-term Ang II stimulation (6 to 24 hours) increased NAD(P)H oxidase subunit expression. c-Src inhibition decreased abundance of gp91phox, p22phox, and p47phox. Confirmation of c-Src-dependent regulation of NAD(P)H oxidase was tested in VSMCs from c-Src-/- mice. Ang II-induced *O2- generation was lower in c-Src-/- than c-Src+/+ counterparts. This was associated with decreased p47phox phosphorylation, blunted Ang II-stimulated NAD(P)H oxidase activation, and failure of Ang II to increase subunit expression.

CONCLUSIONS

c-Src regulates NAD(P)H oxidase-derived *O2- generation acutely by stimulating p47phox phosphorylation and translocation and chronically by increasing protein content of gp91phox, p22phox, and p47phox in Ang II-stimulated cells. These novel findings identify NAD(P)H oxidase subunits, particularly p47phox, as downstream targets of c-Src.

Study of microdeletions in the Y chromosome of infertile men with idiopathic oligo- or azoospermia

PURPOSE

To determine the relationships between idiopathic oligo- or azoospermia and microdeletions of the Y chromosome.

METHODS

Eighteen Y-linked sequence-tagged sites (STSs) in AZF (Azoospermia Factor) region were screened by means of multiplex PCR (Polymerase Chain Reaction) in 50 idiopathic infertile men, including 16 patients with azoospermia, 13 severe oligospermia, and 21 oligospermia.

RESULTS

Microdeletions in the genomic DNA were observed in 8 of 50 cases, 3 with azoospermia, I severe oligospermia, and 4 oligospermia. Total deletion rate was 16.0% (8/50). The deletion regions were concentrated on AZFd and AZFc.

CONCLUSIONS

Microdeletions of the Y chromosome are an important cause for idiopathic oligo- or azoospermia. Multiplex PCR is a useful technique for detecting the microdeletions. To avoid transmission to their offspring, patients with idiopathic oligo- or azoospermia should be screened for microdeletions of the Y chromosome before ICSI treatment for infertility.

[Evaluation of protective efficacy of two tuberculosis DNA vaccines by lung histopathological analysis]

OBJECTIVE

To evaluate the protective efficacy of MPT64 and ESAT6 DNA vaccines from M. tuberculosis.

METHODS

BALB/c mice were randomly divided into five groups and subjected to the following treatments respectively, i.e. immunized with saline (A), plasmid vector (B), M. bovis BCG (C), MPT64 DNA vaccine (D) or ESAT6 DNA vaccine (E); and then infected by intraperitoneal injection with M. tuberculosis H37Rv. The lung histopathological changes were observed 5 or 10 weeks after infection by microscopy.

RESULTS

At 5 weeks after infection, the lung lesions in the mice of group A and B had inflammatory infiltration with epithelial cell granulomas. In the mice of group C, main pathological changes were epithelial cell granulomas with moderate granulate hyperplasia in alveolar walls. The lung lesions of 3 mice in group D and 1 mice in group E were similar to those seen in the mice in group A and B. The lung lesions of 2 mice in group D and 4 mice in group E were similar to those seen in the mice in group C. At 10 weeks after infection, their tuberculous pneumonia tended to recovery. For the mice in groups A, B and D, their lung pathology exhibited tuberculous granulomas consisted of numerous macrophages, lymphocytes and a few epithelial cells with moderate granulate hyperplasia in alveolar walls. For the mice in groups of C and E, their lung developed epithelial cell and lymphocytic granulomas with moderate to severe granulate hyperplasia in alveolar walls. Lung tissue necrosis was not observed in any mouse.

CONCLUSIONS

MPT64 and ESAT6 DNA vaccines from M. tuberculosis could enhance immunity against M. tuberculosis. The protective efficacy of ESAT6 DNA vaccine is stronger than that of MPT64 DNA vaccine, but not stronger than that of Mycobacterium bovis BCG.

Inhibition of Th1- and Enhancement of Th2-Initiating Cytokines and Chemokines in Trichosanthin- Treated Macrophages

Trichosanthin (TCS), the major effective component from Chinese herb Trichosanthes Kirilowii Maxim, is also a potent allergen. Our previous work has shown that TCS can upregulate interleukin-4 (IL-4) and interleukin-13 (IL-13) while inhibit interferon-gamma (IFN-gamma) in mesenteric lymph node cells after TCS immunization. Thus, TCS can arouse a T helper 2 (Th2) response in the draining lymph node. However, little is known about the early effects of TCS on antigen-presenting cells, the initiator of T cell response. In the current study, the effects of TCS on macrophage cytokines and chemokine expression were investigated. Peritoneal macrophages were treated with or without TCS in the presence of lipopolysaccharide (LPS). We found that TCS increased macrophage interleukin-10 (IL-10) and monocyte chemoattractant protein-1 (MCP-1) expression, whereas it decreased interleukin-12 (IL-12) and tumor necrosis factor-alpha (TNF-alpha) expression. Our study clearly demonstrated that TCS, as an allergen, has differential effects on macrophage Th1/Th2 initiative factors, effects that are likely to facilitate its inducing of Th2 and immunoglobulin E (IgE) response.

Hepatitis B virus genotype distribution among chronic hepatitis B virus carriers in Shanghai, China

OBJECTIVE

Hepatitis B virus (HBV) genotype distribution is still unclear in China, where a high prevalence of HBV infection exists, although it is well known that HBV can be classified into six genotypes based on intergroup divergence. The aim of this study was to investigate the epidemiological distribution of HBV genotypes and to clarify further the genotype-related differences in the pathogenicity of HBV.

METHODS

Seminested PCR and restriction fragment length polymorphism analysis were conducted in 97 asymptomatic HBV carriers (ASC) and 46 chronic hepatitis (CH), 37 liver cirrhosis (LC) and 44 hepatocellular carcinoma (HCC) patients in Shanghai, China.

RESULTS

Two hundred and twenty samples (98.2%) were positive for HBV DNA, and of these, 3 (1.4%), 38 (17.2%) and 179 (81.4%) were classified as genotype A, B and C, respectively. There was a statistically significant difference in the distribution of genotypes B and C among various categories of liver diseases (p < 0.01). The distribution of genotype C showed an increasing trend from ASC, CH and LC to the HCC group; in contrast, the distribution of genotype B showed a decreasing trend in the same order. HBeAg positivity was higher in genotype C than in genotype B in all the subjects or in the ASC group alone (p < 0.05, p < 0.01, respectively). More severe liver damage and a higher mean age were observed in genotype C than in genotype B (p < 0.01, p < 0.05, respectively).

CONCLUSIONS

These results indicate the following: (1) genotypes A, B and C of HBV exist in Shanghai, China; (2) genotype C is the major genotype in this area; (3) genotype C is associated with the development of severe liver diseases, and (4) genotype B has a relatively good prognosis.

Depth-resolved two-dimensional stokes vectors of backscattered light and mueller matrices of biological tissue measured with optical coherence tomography

Mueller matrices provide a complete characterization of the optical polarization properties of biological tissue. A polarization-sensitive optical coherence tomography (OCT) system was built and used to investigate the optical polarization properties of biological tissues and other turbid media. The apparent degree of polarization (DOP) of the backscattered light was measured with both liquid and solid scattering samples. The DOP maintains the value of unity within the detectable depth for the solid sample, whereas the DOP decreases with the optical depth for the liquid sample. Two-dimensional depth-resolved images of both the Stokes vectors of the backscattered light and the full Mueller matrices of biological tissue were measured with this system. These polarization measurements revealed some tissue structures that are not perceptible with standard OCT.

Testing Thurstonian Case V ranking models using posterior predictive checks

This paper presents the results of a Monte Carlo study which investigates the validity of the method of posterior predictive checks (PPC) for testing the fit of a Thurstonian Case V ranking model. The PPC method is employed as an alternative to standard goodness-of-fit tests which are of limited use even when the number of items to be ranked is small. Several test quantities are formed to assess the fit of the Case V ranking model to data for various sample sizes and for two types of violations of the Case V assumptions: heterogeneous stimulus variances and rankers from different populations. The study concludes that the PPC method is useful in detecting local and global misfits of a Thurstonian Case V model, even when the ranking data are sparse.

The initial dental health status of British Army Gurkha recruits

AIM

To describe the initial dental health status of British Army Gurkhas who were recruited in 1999 and to compare the present caries data with previous unpublished data from before 1970 and 1983.

DESIGN AND SETTING

A clinical examination was conducted on the 228 Gurkhas, the entire UK intake for 1999, during their second week of military training. The focus of the examinations was on caries experience. A questionnaire was employed to collect demographic data as well as information on the recruits' reported dental behaviour and beliefs.

RESULTS

1999 recruits who reported a dental problem within the past year were significantly more likely to have visited a dentist before compared to those recruits who reported no dental problems. The frequency distributions of D3MFT for the 1983 and 1999 recruits were very similar.

CONCLUSIONS

Gurkha men are at relatively low risk of dental caries and predicted treatment time suggests a relatively small use of resources would be needed to make this group dentally fit. These recruits are an extremely homogeneous group who remain discernible from the general Nepalese population.

[FTIR and fluorescence studies on the europium complexes of multiple ligands]

A series of EuA(m).nB complexes with different molar ratio of ligands and various concentrations of protecting agent were synthesized (A is thenoyltrifluoroacetone, B is a kind of P = O group compound). The properties of these complexes were investigated by FTIR and fluorescence spectroscopy. The fluorescent intensity of complex is related to the reaction condition, the components of complexes.

Propagation of polarized light in turbid media: simulated animation sequences

A time-resolved Monte Carlo technique was used to simulate the propagation of polarized light in turbid media. Calculated quantities include the reflection Mueller matrices, the transmission Mueller matrices, and the degree of polarization (DOP). The effects of the polarization state of the incident light and of the size of scatterers on the propagation of DOP were studied. Results are shown in animation sequences.

Frequency-swept ultrasound-modulated optical tomography in biological tissue by use of parallel detection

A frequency-swept ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. The ultrasound-modulated laser light reflects the local optical and mechanical properties in the ultrasonic beam and can be used for tomographic imaging of the tissue. Sweeping the ultrasonic frequency provides spatial resolution along the ultrasonic axis, which is scalable with the frequency span of the sweep. Two-dimensional images of biological tissue with buried objects were successfully obtained experimentally.

The hinge of the human papillomavirus type 11 E2 protein contains major determinants for nuclear localization and nuclear matrix association

The E2 protein of papillomaviruses is a site-specific DNA binding nuclear protein. It functions as the primary replication origin recognition protein and assists in the assembly of the preinitiation complex. It also helps regulate transcription from the native viral promoter. The E2 protein consists of an amino-terminal (N) trans-acting domain, a central hinge (H) domain, and a carboxyl-terminal (C) protein dimerization and DNA binding domain. The hinge is highly divergent among papillomaviruses, and little is known about its functions. We fused the enhanced green fluorescent protein (GFP) with the full-length human papillomavirus type 11 (HPV-11) E2 protein and showed that the resultant fusion, called gfpE2, maintained transcription and replication functions of the wild-type protein and formed similar subnuclear foci. Using a series of GFP fusion proteins, we showed that the hinge conferred strong nuclear localization, whereas the N or C domain was present in both cytoplasm and nucleus. Biochemical fractionation demonstrated that the N domain and hinge, but not the C domain, independently associated with the nuclear matrix. Mutational analyses showed that a cluster of basic amino acid residues, which is conserved among many mucosotropic papillomaviruses, was required for efficient nuclear localization and nuclear matrix association. This mutation no longer repressed the HPV-11 upstream regulatory region-controlled reporter expression. However, a very small fraction of this mutant colocalized with E1 in the nucleus, perhaps by a piggyback mechanism, and was able to support transient replication. We propose that the hinge is critical for the diverse regulatory functions of the HPV-11 E2 protein during mRNA transcription and viral DNA replication.

[Dural arterovenous fistula involving cavernous sinus]

OBJECTIVE

To study the pathogenesis and treatment of dural arteriovenous fistulas (DAVFS) involving the cavernous sinus.

METHODS

32 cases were embolized with particle by microcatheterization via endovascular approach and ervation by digital substraction angiography. Of the 32 cases, 14 were embolized by microsoils through superior petrosal sinus approach into the cavernous sinus.

RESULTS

In 28 of the 32 cases the fistulas were completely embolized angiographically. The fistulas were partly embolized in 4 of the 32 cases. The carotid artery was compressed for 6 months. One week later, the fistula disappeared angiographically. No fistulas were found during the follow-up for 6 months to 8 years.

CONCLUSION

Endovascular treatment of DAVFS involving the cavernous sinus is effective.

Crystallization and preliminary X-ray analysis of luffaculin, a ribosome-inactivating protein from sponge-gourd seeds

Luffaculin is a ribosome-inactivating protein. Crystals suitable for X--ray diffraction were first obtained using the hanging-drop vapour-diffusion method. X-ray studies show that the crystals belong to space group C2, with unit-cell parameters a = 89.90, b = 59.82, c = 55.18 A, beta = 120.81 degrees, and have one molecule in the crystallographic asymmetric unit. The crystals diffract X-rays to at least 2.0 A resolution.

Theoretical and experimental studies of ultrasound-modulated optical tomography in biological tissue

Ultrasound-modulated optical tomography in biological tissue was studied both theoretically and experimentally. An ultrasonic beam was focused into biological tissue samples to modulate the laser light passing through the ultrasonic beam inside the tissue. The ultrasound-modulated laser light reflects the local optical and mechanical properties in the ultrasonic beam and permits tomographic imaging of biological tissues by scanning. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. Two-dimensional images of biological tissues were successfully obtained experimentally with a laser beam at either normal or oblique incidence, which showed that ultrasound-modulated optical tomography depends on diffuse light rather than on ballistic light. Monte Carlo simulations showed that the modulation depth decreased much more slowly than the diffuse transmittance, which indicated the possibility that even thicker biological tissues can be imaged with this technique.

Full-field mapping of ultrasonic field by light-source-synchronized projection

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transducer operated in continuous-wave mode. This method is very straightforward to implement and can be combined with the traditional tomographic reconstruction technique to obtain the 3D distribution of an ultrasonic field.

Monte Carlo simulation of an optical coherence tomography signal in homogeneous turbid media

The Monte Carlo technique with angle biasing is used to simulate the optical coherence tomography (OCT) signal from homogeneous turbid media. The OCT signal is divided into two categories: one is from a target imaging layer in the medium (Class I); the other is from the rest of the medium (Class II). These two classes of signal are very different in their spatial distributions, angular distributions and the numbers of experienced scattering events. Multiply scattered light contributes to the Class I signal as well as the Class II signal. The average number of scattering events increases linearly with the probing depth. The Class II signal decays much more slowly than the Class I signal whose decay constant is close to the total attenuation coefficient of the turbid medium. The effect of the optical properties of the medium on the Class I signal decay is studied.

[Long-term effect of lamivudine treatment in chronic hepatitis B virus infection]

OBJECTIVE

To evaluate the long-term effect of lamivudine on the loss of serum HBV DNA, HBeAg/antiHBe seroconversion and ALT levels in chronic hepatitis B patients and its safety profile and tolerance with multi-center, randomized, double blind and placebo controlled trial.

METHOD

429 patients with chronic HBV infection as defined by positive HBsAg, HBeAg and HBV DNA were enrolled and randomized into lamivudine and placebo groups. 322 patients received lamivudine 100 mg daily and 107 patients received placebo treatment for 12 weeks. Then, all patients were offered a further 40 weeks of open label lamivudine treatment. The efficacy and safety were evaluated with clinical, biochemical, hematological and virological parameters.

RESULTS

After 12 weeks treatment, HBV DNA response (serum HBV DNA < 1.6 ng/L) rate in lamivudine group was higher than in placebo group (92.2% VS 14.1%, P < 0.01); but at week 52, there was no difference between lamivudine and placebo/lamivudine groups (71.0% VS 77.7%, P > 0.05). Rate of HBV DNA breakthrough in lamivudine group was higher than in placebo/lamivudine group (24.4% VS 8.5%, P < 0.01). Proportion of HBeAg/anti-HBe seroconversion had no difference in two groups (7.5% VS 5.2%, P > 0.05). By week 12, ALT normalization rate in lamivudine group was higher than in placebo group (60.3% VS 27.5%, P < 0.01); but after 52 weeks treatment, there was no difference between two groups (70.9% VS 74.5%, P > 0.05). At week 48, HBV YMDD mutation rate in lamivudine group was higher than in placebo/lamivudine group (14.6% VS 5.0%, P < 0.05). The incidence of adverse events was similar for both lamivudine and placebo/lamivudine group up to week 12 and 52. There was few severe drug-related adverse event.

CONCLUSION

Sustained HBV replication suppression could be obtained from long-term treatment with lamivudine 100 mg daily accompanied with good tolerance and safety.

A randomized double-blind placebo-controlled study of lamivudine in the treatment of patients with chronic hepatitis B virus infection

OBJECTIVE

To evaluate the effect of lamivudine on the loss of serum hepatitis B virus (HBV) DNA, HBeAg/antiHBe seroconversion and ALT levels in chronic hepatitis B patients and its safety profile and tolerance compared with placebo.

METHODS

Four hundred and twenty-nine patients with chronic HBV infection as defined by positive HBsAg, HBeAg and HBV DNA were enrolled and randomized into lamivudine and placebo groups. Three hundred and twenty-two patients received lamivudine 100 mg daily and 107 patients received placebo treatment for 12 weeks. Then, all patients were offered a further 9-month open label lamivudine treatment. The efficacy and safety were evaluated with clinical, biochemical, hematological and virological parameters.

RESULTS

During the 12-week treatment period, 92.2% of lamivudine treated patients became HBV DNA negative (below 1.6 pg/ml) compared with only 14.1% of those receiving placebo (P < 0.01). At the end of 12 week, the sustained negative rate for HBV DNA in the lamivudine treated group was 78.5% compared with the placebo group (11.1%; P < 0.01). There was a trend to a high proportion of patients treated with lamivudine to lose HBeAg (8.1%) and develop antiHBe (10.2%) than treated with placebo (5.3% and 6.4% respectively), but this difference was not statistically significant. Patients with elevated ALT levels at baseline became normal in 60. 3% of the lamivudine treated group compared with the placebo group where only 27.5% were normal (P < 0.01). Lamivudine was well tolerated in a dose of (100 mg daily) and the overall incidence of adverse events was similar to that of the placebo.

CONCLUSIONS

Lamivudine (100 mg daily) is very effective in the inhibition of HBV replication, indicated by the rapid loss of serum HBV DNA, and often accompanied by a decrease of serum ALT levels. Lamivudine is well tolerated without severe adverse events during treatment.