A simplified tumour model established via Epstein-Barr virus-encoded, nasopharyngeal carcinoma-derived oncogene latent membrane protein 1 in immunocompetent mice

The expression and immune modulation of Epstein-Barr virus-encoded oncogene latent membrane protein 1 (N-LMP1) is essential in the pathogenesis of nasopharyngeal carcinoma. In previous studies, cell transformation has been induced by the expression of EBV-encoded N-LMP1 in non-tumour BALB/c-3T3 cells and these cells have then been used to form tumours in T-cell-deficient nude mice. However, studies using this model have been limited by the lack of a competent immune system. To facilitate the study of immune components in N-LMP1-driven oncogenesis, we herein developed a simplified N-LMP1-derived tumour model in immunocompetent mice. Cell transformation was induced by the expression of N-LMP1 in BALB/c-3T3 cells, and these transformants were used to induce oncogenesis in BALB/c mice. In contrast to the 100% successful tumour-induction rate in nude mice treated with monodispersed transformed cells, the tumour incidence in BALB/c mice was only 5-36%. However, the transplantation of tumour fragments into BALB/c mice yielded a reproducible tumour-induction rate of >85%, which is acceptable for most of the research needs. This novel model of N-LMP1-directed oncogenesis in an immunocompetent environment may serve as an important platform for the future assessment of N-LMP1-targeted tumour therapies.

Metritis, valvular endocarditis, and septicemia by Actinobacillus equuli in a gilt in the United States

A 1-year-old pregnant Yorkshire gilt was found dead with no previous clinical signs. Gross findings included metritis, splenomegaly, and valvular endocarditis. Bacterial endocarditis (in the mitral and tricuspid valves) and metritis with dissemination to multiple organs was diagnosed by using histologic examination. Gram-negative coccobacillary organisms present in the valvular lesions were characterized as Actinobacillus equuli by using polymerase chain reaction examination on formalin-fixed, paraffin-embedded tissues (FFPE). A. equuli is rarely reported as a cause of septicemia in pigs in Europe. A. equuli in pigs in the United States has been reported only twice and not, to our knowledge, in the last 30 years. This is the first time that molecular techniques have been used to characterize this organism in FFPE porcine tissues.

Metastasis in para-aortic lymph nodes in patients with advanced gastric cancer, treated with extended lymphadenectomy

BACKGROUND/AIMS

Lymph node dissection is an essential component of curative resection for advanced gastric cancer. To improve the survival of N2 patients, Asian surgeons have been performing D2+para-aortic lymph node dissection. The current study presents the results of lymph node status from multicenter trial of D2 and D2 + para-aortic nodal (No.16) dissection (D4 dissection).

METHODOLOGY

Patients enrolled in the study had potentially curable gastric adenocarcinoma in an advanced stage, T2, T3 or T4/N1 or N2. Patients were randomized to undergo either D2 or D4 gastrectomy.

RESULTS

Two hundred and seventy patients were registered and 136 and 134 patients were allocated into the D2 or D4 group, respectively. The average nodal yield of No.16 in D4 group was 18.4 +/- 14.1, ranging from 2 to 84. No.16 metastasis was detected in 12 (9.0%) of 134 D4 patients. One, 9 and 2 patients had simultaneous involvement in N1, N2, and N3 (No.8p, 12, 13 or 14). Namely, in 39 patients who were diagnosed as N2 from the lymph node status in N1 and N2 levels, nine (23.0%) patients had No.16 metastasis. The stage migration by D4 was found in 10 (7.5%). Logistic regression analysis revealed that the stations of No.7 and No.8 were the significant predictors of No.16 involvement.

CONCLUSIONS

The present study may strongly suggest that prophylactic D4 dissection may be indicated for patients with N2 involvement, and that No.7 and No.8 are the junctional nodes for D4 dissection.

Possible therapies of septic shock: based on animal studies and clinical trials

The intention of this review is to give a brief overview of the continuously expanding field of sepsis therapy based on recent studies with animal models and clinical trials. Over the past few years, it has become apparent that the mechanisms controlling this disease are more complex than was previously thought, with factors such as free radicals, nuclear factors, and enzyme co-factors all contributing in the control of the pathogenesis of sepsis as well and improvements in the morbidity. Recent advances at the molecular biology level have facilitated the development of a whole new field of research. In addition, a number of groups have also shown that free radicals can modulate the expression of several genes. Probably an effect that is due to an interaction between free radicals and transcription factors. Further elucidation of the signals that influence the production and actions of free radicals will, without doubt, further our understanding of the numerous pathophysiological processes involved in sepsis. For these reasons, there is considerable interest in alternative treatment modalities which focus on recent animal studies. These recent experimental approaches to the therapy of sepsis are discussed in light of each step in the complex inflammatory cascade involved and compared to traditional approaches to the prevention and therapy of sepsis and septic shock.

Upregulation of endothelial heme oxygenase-1 expression through the activation of the JNK pathway by sublethal concentrations of acrolein

Acrolein is a highly electrophilic alpha,beta-unsaturated aldehyde that is present in cigarette smoke. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme activated by various such electrophilic compounds. In this study, the regulatory effects of acrolein upon the expression of HO-1 were investigated in endothelial cells (ECs). We demonstrate that acrolein induces the elevation of HO-1 protein levels, and subsequent enzyme activity, at non-cytotoxic concentrations. An additional alpha,beta-unsaturated aldehyde, cinnamaldehyde, was also found to increase HO-1 expression and have less cytotoxicity than acrolein. Moreover, acrolein-mediated HO-1 induction is abrogated in the presence of actinomycin D and cycloheximide. Nrf2 is a transcription factor involved in the induction of HO-1 through an antioxidant response element (ARE) in the promoter region of the HO-1 gene. We show that acrolein induces Nrf2 translocation and ARE-luciferase reporter activity. Acrolein was also found to induce the production of both superoxide and H2O2 at levels greater than 100 microM. However, with the exception of NAC, no antioxidant generated any effect upon acrolein-dependent HO-1 expression in ECs. Our present findings suggest that reactive oxygen species (ROS) may not be a major modulator for HO-1 induction. Using buthionine sulfoximine to deplete the intracellular GSH levels further enhanced the effects of acrolein. We also found that cellular GSH level was rapidly reduced after both 10 and 100 microM acrolein treatment. However, after 6 h of exposure to ECs, only 10 microM acrolein treatment increases GSH level. In addition, only the JNK inhibitor SP600125 and tyrosine kinase inhibitor genistein had any significant inhibitory impact upon the upregulation of HO-1 by acrolein. Pretreatment with a range of other PI3 kinase inhibitors, including wortmannin and LY294002, showed no effects. Hence, we show in our current experiments that a sublethal concentration of acrolein is in fact a novel HO-1 inducer, and we further identify the principal underlying mechanisms involved in this process.

CadA, the Cd2+-ATPase from Listeria monocytogenes, can use Cd2+ as co-substrate

CadA is a membrane protein of the P-type ATPase family which is the major determinant of the resistance to Cd2+ in Listeria monocytogenes. During its catalytic cycle, CadA undergoes auto-phosphorylation from ATP at Asp398, which allows Cd2+ translocation across the membrane. In the reverse mode, Asp398 is phosphorylated from Pi. From the data obtained so far, the CadA catalytic mechanism is similar to that proposed for the sarcoplasmic reticulum Ca2+-ATPase, the model of the P-type ATPase family. We show here that CadA is sensitive to two different ranges of Cd2+ concentration. The 0.1-10 microM range of added CdCl2 corresponds to Cd2+ binding at the transport site of unphosphorylated CadA which induces the reaction of the enzyme with ATP and impairs its reaction with Pi. The 0.1-1 mM range of added CdCl2 could correspond to Cd2+ binding to the transport site accessible from the extracellular medium. In addition, although it is widely accepted that the actual substrate of P-type ATPases is the MgATP complex, we show here that CadA can also perform its cycle in the absence of Mg2+, using CdATP in the place of MgATP at the catalytic site.

Listeric meningoencephalomyelitis in a cougar (Felis concolor): characterization by histopathologic, immunohistochemical, and molecular methods

Listeria monocytogenes has been recognized as an important food-borne pathogen in animals. Records of the disease caused by this bacterium in large felids are, however, rare. The nervous form of listeriosis was diagnosed in a 12-year-old male cougar (Felis concolor) with a several-day history of neurologic disease characterized by excess salivation, head pressing, and circling that progressed to recumbency and death. Microscopically, the main alteration in the brain and spinal cord was a variably severe meningoencephalomyelitis composed mainly of mononuclear cell aggregates with fewer neutrophils. L. monocytogenes was isolated from the brain by microbiological culture, and L. monocytogenes antigen was detected in formalin-fixed, paraffin-embedded sections of brain and spinal cord by immunohistochemical analysis. On the basis of the nucleotide sequence of the 16S rRNA gene, the isolated strain was determined to be serotype 1/2a. Food-borne transmission of the bacterium was suspected, but food was not available for testing.

Operative morbidity and mortality after D2 and D4 extended dissection for advanced gastric cancer: a prospective randomized trial conducted by Asian surgeons

BACKGROUND/AIMS

A randomized study was performed to evaluate morbidity and mortality after D2 (level 1 and 2 lymphadenectomy) and D4 (D2 plus lymphadenectomy of para-aortic lymph nodes) dissection for advanced gastric cancer.

METHODOLOGY

Two hundred and fifty-six patients with advanced gastric adenocarcinoma were enrolled (128 to each group). Patients were randomly allocated into D2 (N = 128) or D4 (N = 128) group. The first and second tiers of lymph nodes are removed in D2 dissection. In D4 gastrectomy, the paraaortic lymph nodes were additionally removed.

RESULTS

There was no indication of significant distribution bias with regard to age, sex, T-grade, and N-grade between the two groups. Operation time of D4 gastrectomy (369 +/- 120 min) was significantly longer than that of D2 gastrectomy (273 +/- 1103 min), and blood loss of the D4 group (872 +/- 683 mL) was significantly greater than that of the D2 group 571 +/- 527 mL (P < 0.001). Five (4%) and two (2%) medical complications developed in the D2 and D4 groups, respectively. Surgical complications developed in 28 (22%) and 48 patients (38%) after D2 and D4 gastrectomy. The most common complications were anastomotic leakage, pancreatic fistula, and abdominal abscess. Pancreatic fistula developed in 6 (19%) of 32 patients after D4 plus pancreatosplenectomy, but the incidence of pancreatic fistula after D2 gastrectomy plus pancreatosplenectomy was low (6%, 1/16). Two patients died within 30 days of operation (0.8%, 2/256), and each patient belonged to the D2 and D4 group.

CONCLUSIONS

Although there is a significantly higher surgical complication rate in D4 dissection, D4 dissection can be done safely as D2 dissection when performed by well-trained surgeons.

Application of the mixed venous blood concentration equation in desflurane anesthesia

BACKGROUND

We have previously proposed an equation derived from Fick's law and Lin's concept of effective blood concentration (EBC) to calculate the mixed venous blood concentration (MVBC) of isoflurane. Desflurane has a lower blood/air partition coefficient than isoflurane and, as such, promotes a faster induction and recovery from anesthesia. In this study, we investigated the application of the MVBC equation to predict the MVBC of desflurane.

METHODS

We maintained anesthesia with a fixed inspired concentration (CI) of desflurane (10%) during cardiac anesthesia in 11 patients. In order to measure the real concentrations of desflurane in mixed venous blood, pulmonary arterial blood samples were collected at different time points via a Swan-Ganz catheter for gas chromatographic-mass spectrometric determination. The relationship between the calculated concentrations and the actual blood sample concentrations of desflurane in mixed venous blood was investigated. Lin's EBC method was also used and the results were compared with those of MVBC.

RESULTS

The calculations from our derived MVBC equation and the actual blood concentrations showed a similar kinetic pattern; the concentration levels were approximately the same and correlated well (r = 0.89) during anesthesia. However, the EBC method failed to accurately estimate the actual blood concentrations.

CONCLUSIONS

The results demonstrate that our equation, but not the EBC method, may be useful for estimating pulmonary blood concentrations of desflurane. The clinical significance and the importance of the method merit further investigation.

15-Deoxy-Δ12,14-prostaglandin J2 suppresses IL-6-induced STAT3 phosphorylation via electrophilic reactivity in endothelial cells

In this study, the effects of 15d-PGJ(2) were investigated in IL-6-activated endothelial cells (ECs). 15d-PGJ(2) was found to abrogate phosphorylation on tyr705 of STAT3 in IL-6-treated ECs, in a dose- and time-dependent manner, but did not inhibit serine phosphorylation of STAT3 and the upperstream JAK2 phosphorylation. Other PPAR activators, such as WY1643 or ciglitazone, had no effect upon IL-6-induced STAT3 phosphorylation. Additionally, neither orthovanadate nor l-NAME treatment reverses the inhibition of STAT3 phosphorylation by 15d-PGJ(2). Otherwise, the effect of 15d-PGJ(2) requires the alpha,beta-unsaturated carbonyl group in the cyclopentane ring. A 15d-PGJ(2) analog, 9,10-Dihydro-15d-PGJ(2), which lack alpha,beta-unsaturated carbonyl group showed no increase in ROS production and no effect in inhibition of IL-6-induced STAT3 phosphorylation. The electrophilic compound, acrolein, mimics the inhibition effect of 15d-PGJ(2). Among the antioxidants, only NAC and glutathione reversed the effects of 15d-PGJ(2). NAC, glutathione and DTT all reversed the inhibition of STAT3 phosphorylation when preincubated with 15d-PGJ(2). The inhibition of ICAM-1 gene expression by 15d-PGJ(2) was abrogated by NAC and glutathione in IL-6-treated ECs. Taken together, these results suggest that 15d-PGJ(2) inhibits IL-6-stimulated phosphorylation on tyr705 of STAT3 dependent on its own electrophilic reactivity in ECs.

Upregulation of heme oxygenase-1 by Epigallocatechin-3-gallate via the phosphatidylinositol 3-kinase/Akt and ERK pathways

Heme oxygenase-1 (HO-1) is a cytoprotective enzyme activated by various phytochemicals and we examined the ability of Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, to upregulate HO-1 expression in endothelial cells (ECs). We demonstrate that EGCG induces HO-1 expression in a concentration- and time-dependent manner. Furthermore, EGCG-mediated HO-1 induction was abrogated in the presence of actinomycin D and cycloheximide, indicating that this upregulation of HO-1 occurred at the transcriptional level. EGCG also upregulates Nrf2 levels in nuclear extracts and increases ARE-luciferase activity. Furthermore, EGCG is the most potent inducer of HO-1 expression of the different green tea constituents that we analyzed, but had no detectable cytotoxic effects over the 25-100 microM dosage range. The inhibition of intracellular ROS production by N-acetylcysteine (NAC), glutathione (GSH), superoxide dismutase (SOD), catalase and the mitochondrial complex I inhibitor, rotenone, results in a decrease in EGCG-dependent HO-1 expression. In addition, we determined that tyrosine kinase is involved in EGCG induction of HO-1 as this is abrogated by genistein. ECs treated with EGCG exhibit activation of Akt and ERK1/2. In addition, pharmacological inhibitors of phosphatidylinositol 3-kinase and MEK1/2, which are upstream of Akt and ERK1/2, respectively, attenuate EGCG-induced HO-1 expression. On the other hand, pretreatment of these cells with EGCG exerts significant cytoprotective effects against H2O2, suggesting that the induction of HO-1 is an important component in the protection against oxidative stress. Hence, EGCG is a novel phytochemical inducer of HO-1 expression and we further identify the principal underlying mechanisms involved in this process.

Apoptotic markers on lymphocytes and monocytes are unchanged during single hemodialysis sessions using either regenerated cellulose or polysulfone membranes

BACKGROUND

There is an increased rate of apoptosis of peripheral blood mononuclear cells (PBMCs) in patients undergoing hemodialysis (HD), but little is known about how different dialysis membranes may contribute to the process. We, therefore, studied the influence of two different dialysis membranes on apoptotic markers during HD.

METHODS

8 healthy controls and 8 patients on regular HD 3 times per week were enrolled in this cross-controlled study. Patients received HD using polysulfone and then regenerated cellulose dialysis membranes for one week each, sequentially. Serum was collected for C-reactive protein (CRP) detection; flow cytometry with dual antibody staining was used to measure the apoptotic markers Fas (CD95), FasL (CD 178) and TNF-R2 (CD120b) in T cells (CD3+), B cells (CD19+), and monocytes (CD14+) at 0, 15, 120 and 240 min after starting HD. We also measured total leukocyte numbers and differential white cell counts.

RESULTS

Hemodialysis patients revealed lymphocytopenia, monocytopenia, higher CRP levels and higher Fas and TNF-R2 expression on lymphocytes and monocytes at baseline when compared with normal controls. Leukocyte numbers, including neutrophils, lymphocytes and monocytes, dropped significantly after 15 min of dialysis. There were no significant differences in Fas levels during hemodialysis on T and B lymphocytes or on monocytes. T lymphocyte FasL (CD 178) levels remained unchanged throughout the process. There was a significantly lower overall level of CD120b at 15 min of HD, whereas this marker was higher on monocytes after dialysis. There were no significant differences in the levels of apoptotic markers between the two membranes.

CONCLUSION

Our results suggest that uremia itself contributes to PBMC apoptosis. The two different dialysis membranes used in this study did not influence apoptotic markers on PBMCs significantly, but increased TNF-R2 expression on monocytes during a single dialysis session.

Resveratrol suppresses IL-6-induced ICAM-1 gene expression in endothelial cells: effects on the inhibition of STAT3 phosphorylation

Resveratrol, a polyphenolic phytoaxelin present in red wine, has been suggested to protect against atherosclerosis and cardiovascular disease because of its antioxidant effects. Intercellular adhesion molecule (ICAM-1), induced by cytokines, has been hypothesized to play a role in the early events during atherosclerosis. In this study we tested the effects of resveratrol upon both IL-6-induced ICAM-1 gene expression and its underlying signaling pathways in endothelial cells (ECs). Resveratrol was found to inhibit both TNFalpha- and IL-6-induced ICAM-1 gene expression at the promoter, transcriptional and protein levels. Resveratrol also abrogates the tyr705 phosphorylation of STAT3 in IL-6-treated ECs, in a dose- and time-dependent manner. Although quercetin had similar effects, resveratrol showed higher inhibitory properties following 2-4 h pretreatments. Resveratrol has been shown to induce the activity of endothelial nitric oxide synthase (eNOS) and increase NO production. Consistent with this, the treatment of ECs with a NO donor (SNAP) reduces IL-6-induced STAT3 phosphorylation. Conversely, exposure of ECs to a NOS inhibitor reversed the effects of resveratrol upon IL-6-induced STAT3 phosphorylation. Furthermore, ECs transfected with constitutively active Rac1 (RacV12) showed increases in ICAM-1 promoter activity, intracellular reactive oxygen species (ROS) levels and STAT3 phosphorylation, and these increases were attenuated by resveratrol treatment. In summary, we demonstrate for the first time that resveratrol inhibits IL-6-induced ICAM-1 gene expression, in part, by interfering with Rac-mediated pathways via the attenuation of STAT3 phosphorylation. This study therefore provides important new insights that may contribute to the proposed beneficial effects of resveratrol in endothelial responses to cytokines during inflammation.

Application of MVBC equation to predict mixed venous blood concentrations of sevoflurane in cardiac anaesthesia

We have proposed an equation for estimating the real-time mixed venous blood concentration (MVBC) of isoflurane in cardiac anaesthesia. However, information related to the application of our method to sevoflurane is lacking. We studied 12 patients undergoing cardiac surgery and anaesthetised with sevoflurane. At different time points, pulmonary arterial blood samples were collected for gas chromatography-mass spectrometry (GC-MS) to determine the real mixed venous concentrations of sevoflurane. The inspired and expired concentrations of sevoflurane, measured by a gas monitor, were used for the MVBC calculations. Using Bland-Altman analyses, we found that the calculated MVBCs accurately represent the actual concentrations of sevoflurane in pulmonary arterial blood, as shown by a near-zero percentage bias with a 0.14% precision between the two concentrations. The results demonstrated that our equation could be a useful method for estimating the pulmonary blood concentration of sevoflurane.

Infectious bursal disease virus recovery from Vero cells transfected with RNA transcripts is enhanced by expression of the structural proteins in trans

Positive sense RNA transcripts of infectious bursal disease (IBD) virus genome segments A and B have previously been shown to be infectious. In this study we demonstrate that recovery of IBD virus from the transfection of Vero cells with positive sense RNA transcripts of genome segments A and B was enhanced by expression of the viral structural proteins VP2 with VP3 or by expression of viral polyprotein VP243 from DNA plasmids in trans. Expression of individual viral proteins VP2, VP3, or VP4 alone from DNA plasmids did not enhance IBD virus recovery. Earliest virus recovery from transfection of positive sense RNA transcripts of genomic segments A and B was at 36 h and mean titers were 10(1.8) pfu/ml. IBD virus was recovered 6 hours after transfection in cells concurrently expressing either VP2 with VP3 or VP243 and mean titers were 10(8.5) pfu/ml or 10(9.2) pfu/ml, respectively. Likewise, expression of the viral polyprotein from DNA plasmid increased the permissiveness of Vero cells for infection with non-culture adapted IBD virus. The titer of recovered non-culture adapted virus from 10(3.3) pfu/ml to 10(10.3) pfu/ml with expression of the viral polyprotein. This report is the first to describe a reverse genetics model for IBD virus with high efficiency of virus recovery for non-culture adapted strains.

Myocardial border detection by branch-and-bound dynamic programming in magnetic resonance images

Dynamic programming (DP) is a mathematical technique for making optimal decisions on the sequencing of interrelated problems. It has been used widely to detect borders in magnetic resonance images (MRI). MRI is noninvasive and generates clear images; however, it is impractical for manual measurement of the huge number of images generated by dynamic organs such as those of the cardiovascular system. A fast and effective algorithm is essential for on-line implementation of MRI-based computer aided measurement and diagnosis. In this paper, a branch-and-bound dynamic programming technique is applied to detect the endocardial borders of the left ventricular. The proposed branch-and-bound method drastically reduces the computational time required in conventional exhaustive search methods. Statistical tests are conducted to verify the CPU time performance of the branch-and-bound technique in comparison to the conventional exhaustive search method.

Experimental acute alcohol pancreatitis-related liver damage and endotoxemia: synbiotics but not metronidazole have a protective effect

OBJECTIVE

The aim of this study was to test the effect of gut manipulation by either novel synbiotics or by metronidazole on either endotoxemia or the severity of liver damage in the course of acute pancreatitis from alcohol ingestion.

METHODS

Sprague-Dawley rats were fed for 1 week through an intragastric tube a liquid diet with either: (i) 1 mL t.i.d. of a mixture of synbiotics (Lactobacillus acidophilus, Lactobacillus helveticus and Bifidobacterium in an enriched medium); (ii) 20 mg/kg t.i.d. metronidazole; or (iii) standard diet. Then, acute pancreatitis was induced by caerulein and when the disease was full-blown, rats were fed an alcohol-rich diet. Synbiotic and metronidazole treatment was given for a further 2 weeks. Transaminase and endotoxemia levels were measured before treatment, after 6 h, after 24 h and 2 weeks later, at the time the rats were killed. Liver samples were obtained for histological analysis.

RESULTS

Synbiotics but not metronidazole improved the acute pancreatitis-induced increase in endotoxemia and transaminase levels. The addition of alcohol worsened these variables to a limited extent in the synbiotic-treated group, while metronidazole had a negative effect on liver damage.

CONCLUSIONS

Gut flora pretreatment with synbiotics was able to effectively protect against endotoxin/bacterial translocation, as well as liver damage in the course of acute pancreatitis and concomitant heavy alcohol consumption. The beneficial effect of synbiotics on liver histology seems to be correlated with endotoxemia. Metronidazole did not produce such a beneficial effect; in fact, it further worsened liver damage when alcohol was added to the background of ongoing acute pancreatic inflammation.

Magnetocardiography of animals in magnetically shielded environment with active compensation

A high-Tc 1st-order electronic superconducting quantum interference device (SQUID) gradiometer system is constructed to study the magnetocardiogram (MCG) of rabbits in a moderately magnetically shielded environment with active compensation. In the noisy hospital environment, the noise cannot be completely reduced with the 1st-order gradiometer, therefore, a reference SQUID with active compensation was used to further reduce the noise level leaking into the room. The MCG system was equipped with a x-y translation bed. We used a low-pass filter with the cut off frequency at 44 Hz, a high-pass filter with the cut off frequency at 0.1 Hz and the 60 Hz notch filter to reduce the power line interference. The noise level of the 1st order gradiometer MCG system in this moderately magnetically shielded room was about 1 pT/square root of Hz1/2 at 1 Hz. The MCG of a normal rabbits was measured with this system and a MCG contour map and a current density distribution was constructed.

Mycobacterium avium subsp. paratuberculosis fibronectin attachment protein facilitates M-cell targeting and invasion through a fibronectin bridge with host integrins

Efficient attachment and ingestion of Mycobacterium avium subsp. paratuberculosis by cultured epithelial cells requires the expression of a fibronectin (FN) attachment protein homologue (FAP-P) which mediates FN binding by M. avium subsp. paratuberculosis. Invasion of Peyer's patches by M. avium subsp. paratuberculosis occurs through M cells, which, unlike other intestinal epithelial cells, express integrins on their luminal faces. We sought to determine if the interaction between FAP-P of M. avium subsp. paratuberculosis and soluble FN enabled targeting and invasion of M cells by M. avium subsp. paratuberculosis in vivo via these surface integrins. Wild-type and antisense FAP-P mutant M. avium subsp. paratuberculosis strains were injected alone or coinjected with blocking peptides or antibodies into murine gut loops, and immunofluorescence microscopy was performed to assess targeting and invasion of M cells by M. avium subsp. paratuberculosis. Nonopsonized M. avium subsp. paratuberculosis preferentially invaded M cells in murine gut loops. M-cell invasion was enhanced 2.6-fold when M. avium subsp. paratuberculosis was pretreated with FN. Invasion of M cells by the antisense FAP-P mutant of M. avium subsp. paratuberculosis was reduced by 77 to 90% relative to that observed for the control strains. Peptides corresponding to the RGD and synergy site integrin recognition regions of FN blocked M. avium subsp. paratuberculosis invasion of M cells by 75 and 45%, respectively, whereas the connecting segment 1 peptide was noninhibitory. Antibodies against the alpha5, alphaV, beta1, and beta3 integrin subunits inhibited M-cell invasion by 52 to 73%. The results indicate that targeting and invasion of M cells by M. avium subsp. paratuberculosis in vivo is mediated primarily by the formation of an FN bridge formed between FAP-P of M. avium subsp. paratuberculosis and integrins on M cells.

Infectious bursal disease virus polyprotein expression arrests growth and mitogenic stimulation of B lymphocytes

Infectious bursal disease virus (IBDV) causes lymphocytolysis and immunosuppression in infected poultry. The IBDV genome encodes a polyprotein VP243 that is post-translationally cleaved by the VP4 protease into the two structural proteins pVP2 and VP3. The objective of the present study was to determine if IBDV polyprotein induced suppression of bursal B lymphocyte growth and their capacity for proliferation. Bursal B cells were examined both for chickens infected with IBDV and for chickens orally inoculated with a DNA construct expressing IBDV VP243 polyprotein. Bursae were collected at 0, 12, 24 and 48 hours after inoculation. Proliferation of bursal B cells (purified AvBu1(+) cells) in response to concanavalin A mitogenic stimulation was significantly suppressed by infection at 1 day old with either the classical STC or variant E strains of IBDV. Oral administration of DNA constructs expressing the IBDV VP243 polyprotein from either the classical STC or variant E strains in the pCR3.1 vector resulted in persistent, moderate levels of construct in the bursa until at least 48 hours after inoculation. The VP243 DNA construct similarly induced suppression of proliferation for bursal lymphocytes independently of the virus infection. Expression of VP243 polyprotein in transiently transfected DT40 B lymphocyte culture also suppressed cell growth and proliferative responses to mitogen stimulation. Polyprotein expression did not affect cell viability and suppression of proliferation probably occurred by means of cell cycle arrest. The expression of the mature viral proteins VP2, VP4 or VP3 did not change the rate of cell proliferation or response of B cell cultures to mitogen. The results suggested that IBDV polyprotein is a mediator of immunosuppression.

NO and KATP channels underlie endotoxin-induced smooth muscle hyperpolarization in rat mesenteric resistance arteries

1 Smooth muscle membrane potential and tension measurements were made in isolated mesenteric resistance arteries from rats exposed to bacterial endotoxin (lipopolysaccharide, LPS; 10 mg kg(-1), i.p.) for 3 h to mimic septic shock syndrome. 2 Over this period, rats developed an endotoxaemic response, assessed in vivo as a 41+/-4 mmHg drop in mean blood pressure, vascular hyporeactivity to noradrenaline (1 microg kg(-1), i.v.) and a significant increase in core body temperature. 3 In mesenteric small resistance arteries from these rats (o.d. 180 - 240 microm), phenylephrine (0.01-3 microm)-evoked contraction was not altered when compared with arteries from sham-operated animals, but the concentration-relaxation curve to acetylcholine (ACh; 0.01 - 3 microm) displayed a small, but significant, shift to the right. 4 The smooth muscle resting membrane potential (-70.3+/-1.6 mV) in arteries from LPS-treated rats was significantly greater than in control arteries (-55.4+/-1.2 mV), but in both cases the smooth muscle was depolarized to a similar potential by the application of N(omega)-nitro-L-arginine methyl ester (L-NAME; 0.3 mm; -54.1+/-2.3 vs -52.4+/-2.5 mV) or glibenclamide (10 microm; -55.0+/-2.1 vs -50.4+/-2.0 mV). 5 ACh (1 microm) elicited a maximal hyperpolarization, which ranged from -14.7+/-3.2 mV (in arteries from LPS-treated rats) to -20.6+/-2.4 mV (in arteries from sham-operated rats), and was not altered by the presence of L-NAME. Levcromakalim (1 microm) increased the smooth muscle membrane potential by around -24 mV in arteries from both sets of experimental animals. 6 These results indicate that at the level of the resistance vasculature, endotoxaemia is associated with pronounced smooth muscle hyperpolarization reflecting the action of NO on KATP channels. These changes were not associated with vascular hyporeactivity or depressed endothelial cell function in vitro, suggesting that mesenteric resistance arteries may not contribute to equivalent changes in vivo.

Cystic fibrosis transmembrane conductance regulator gene screening and clinical correlation in Taiwanese males with congenital bilateral absence of the vas deferens

BACKGROUND

In Taiwan, an area with a very low incidence of cystic fibrosis (CF), we first screened for the most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and looked for clinical correlations in 27 patients with clinically diagnosed congenital bilateral absence of the vas deferens (CBAVD).

METHODS AND RESULTS

The clinical results showed that none of the 27 patients had CF symptoms. We did not detect any definite renal anomaly ultrasonographically. Mutation analysis was carried out on these 27 cases and 46 normal fertile males as controls. No mutations of Delta F508 or R117H were identified in any of the samples analysed. In the screening of IVS8-poly T, five of the 27 CBAVD patients showed the homozygous genotype for 5T/5T, 14 showed the heterozygous genotype for 5T/7T and eight showed the homozygous genotype for 7T/7T. The frequency of 5T alleles was 44.4%, which was significantly higher than in the 46 normal fertile males, for which there was a 5T frequency of 5.4%.

CONCLUSIONS

The absence of major mutations of CFTR genes could be related to the much lower CF incidence in Taiwan. Further investigations into differences in the mutation spectrum of other CFTR genes are needed for a better understanding of the development of Taiwanese-Oriental CBAVD.

Minimally displaced intra-capsular femoral neck fractures in the elderly--comparison of multiple threaded pins and sliding compression screws surgical techniques

PURPOSE

To determine the outcome of treatment for minimally displaced femoral neck fractures using multiple threaded pins versus sliding compression screws for internal fixation.

METHODS

The medical records of 62 consecutive elderly patients with minimally displaced intra-capsular femoral neck fractures who underwent internal fixation of the fracture (37 with multiple threaded pins, and 25 with sliding compression screws) were reviewed. Clinical and radiological assessment of fracture healing at follow-up visits were noted.

RESULTS

In the 55 patients seen for follow-up at 3 months, 21.9% (n=7) of those treated by pinning demonstrated non-union of the fracture, and 0% of fractures treated with sliding compression screws (p=0.02). 46 patients were seen for follow-up at one year, with 10% (n=2) of those treated with sliding compression screws found to have osteonecrosis of the femoral head. The 2 fractures in the group treated by pinning demonstrating non-union at 3 months failed to unite by one year (p=0.11). 34 patients were seen for follow-up for at least 2 years, with no additional complications noted.

CONCLUSION

Using sliding compression screws to treat minimally displaced femoral neck fractures can achieve a higher union rate than using pinning. The reason may be the better stability in the osteoporotic bone. However, osteonecrosis of the femoral head may occur with use of sliding compression screws because of greater intramedullary vascular damage as a result of wider reaming.

Chemopreventive effect of a probiotic preparation on the development of preneoplastic and neoplastic colonic lesions: an experimental study

BACKGROUND/AIMS

A number of studies have suggested a key role played by certain resident gut bacteria in the development of large bowel cancer. The aim of the present study was to test the effect of a novel symbiotic preparation, which has been recently shown to beneficially modify gut ecosystem and systemic immunity, on either preneoplastic and neoplastic changes in a colon carcinogenesis model.

METHODOLOGY

Sprague-Dawley rats were fed a standard diet for 1 week and then were randomly assigned to three groups. The control diet was given to groups A and B, whereas in group C, the same diet plus 2 mL of a probiotic mixture was given throughout the experiment. Thirty rats (groups B, C) each received a weekly subcutaneous injection of azoxymethane at a dose of 15 mg/kg of body weight for 10 weeks. Group A served as a control group and received a subcutaneous injection of saline for 10 weeks. Forty-five rats were sacrificed at 3-week observation and 60 rats at 20-week observation for assessing metaphase index together with aberrant crypt foci and intestinal immune system markers from one hand and tumor occurrence from the other, respectively.

RESULTS

Group A showed a significantly increased metaphase index either in aberrant crypt foci or in "normal appearing" crypts when compared to group A (p < 0.01). Group B rats caused a significant decrease at both sites (p < 0.05). The numbers of lymphocytes derived from the mesenteric lymph nodes in group B rats were significantly decreased (p < 0.01) as compared to either control and to group C. The percentage of CD8 lymphocytes in group C was significantly higher than that in group B. Group C showed a significantly reduced ratio of aberrant crypt foci/colon and of aberrant crypt per colon and per each single focus (p < 0.05). A total of 18 (90%) group B and 10 (50%) group C rats had colon tumors, this difference was significant. The mean number of colon tumors per rat was 2.2 and 1.0 in group B and C, respectively.

CONCLUSIONS

Effective probiotics treatment, through mechanisms still to be fully elucidated (decreased fecal pH, specific reduction of carcinogenetic bacterial enzymes, modulation of gut-associated and systemic immune system etc.) has the potential to exert significant antimutagenic properties against colon cancer.

One-stage revision surgery to treat hip infected nonunion after stabilization with a sliding compression screw

INTRODUCTION

Extracapsular hip infected nonunion after stabilization with a sliding hip screw (SCS) is uncommon and a convincing treatment method has not yet been reported in the literature.

PATIENTS AND METHODS

Thirteen consecutive patients who sustained such a disability were treated with removal of SCS, local radical debridement, vancomycin powder with or without gentamicin solution application, re-insertion of a new SCS, and autogenous cancellous bone grafting. Postoperatively, ambulation with regulated weight bearing was encouraged as early as possible. Infectious microorganisms in 76% (10/13) of the lesion sites were oxacillin-resistant staphylococcus aureus (ORSA).

RESULTS

Twelve patients were followed-up for at least 2 years (range, 2~6 years; median, 4 years) and all nonunions healed. The union rate was 100% (12/12) with a median union period of 4 months (range, 3~6 months). No wound infection recurred at the last follow-up. The satisfactory rate of hip function was 92% (11/12, P<0.001).

CONCLUSIONS

We, therefore, recommend this surgical procedure to treat all patients with a similar disability because of its high success rate and low complication rate.