[Analysis of prognostic factors influencing the outcome of intrahepatic cholangiocarcinoma]

OBJECTIVE

To analyze the clinicopathologic factors influencing the outcome of surgically treated intrahepatic cholangiocarcinoma (ICC) and to explore the proper treatment choice of ICC.

METHODS

The clinicopathological data of 43 surgically treated ICC patients in our hospital were retrospectively analyzed. Of the 43 patients, hepatic resection was performed in 40 patients, ethanol injection in 2, and laparoscopic exploration alone in 1. Kaplan-Meier method and Cox regression model were used for the analysis of factors influencing survival after operation.

RESULTS

The accumulative 1-, 3- and 5-year survival rates were 64.4%, 30.9%, 25.8% for the whole group, and 74.7%, 33.3%, 27.8% for the 40 patients with hepatic resection, respectively. Univariate analysis revealed that tumor size, carcinoembryonic antigen (CEA) level, lymph node involvement and TNM stage were factors significantly affecting the survival (P < 0.05). Cox multivariate analysis demonstrated that only tumor size and lymph node involvement were the independent factors significantly affecting the survival (P < 0.05).

CONCLUSION

Our results show that tumor size and lymph node involvement are independent factors affecting the survival. CEA level and TNM stage are important prognostic factors for surgical management. Radical resection is still the optimal treatment for patient with intrahepatic cholangiocarcinoma.

Differential cellular responses to prolonged LDR-IR in MLH1-proficient and MLH1-deficient colorectal cancer HCT116 cells

PURPOSE

MLH1 is a key DNA mismatch repair (MMR) protein involved in maintaining genomic stability by participating in the repair of endogenous and exogenous mispairs in the daughter strands during S phase. Exogenous mispairs can result following treatment with several classes of chemotherapeutic drugs, as well as with ionizing radiation. In this study, we investigated the role of the MLH1 protein in determining the cellular and molecular responses to prolonged low-dose rate ionizing radiation (LDR-IR), which is similar to the clinical use of cancer brachytherapy.

EXPERIMENTAL DESIGN

An isogenic pair of MMR(+) (MLH1(+)) and MMR(-) (MLH1(-)) human colorectal cancer HCT116 cells was exposed to prolonged LDR-IR (1.3-17 cGy/h x 24-96 h). The clonogenic survival and gene mutation rates were examined. Cell cycle distribution was analyzed with flow cytometry. Changes in selected DNA damage repair proteins, DNA damage response proteins, and cell death marker proteins were examined with Western blotting.

RESULTS

MLH1(+) HCT116 cells showed greater radiosensitivity with enhanced expression of apoptotic and autophagic markers, a reduced HPRT gene mutation rate, and more pronounced cell cycle alterations (increased late-S population and a G(2)/M arrest) following LDR-IR compared with MLH1(-) HCT116 cells. Importantly, a progressive increase in MLH1 protein levels was found in MLH1(+) cells during prolonged LDR-IR, which was temporally correlated with a progressive decrease in Rad51 protein (involved in homologous recombination) levels.

CONCLUSIONS

MLH1 status significantly affects cellular responses to prolonged LDR-IR. MLH1 may enhance cell radiosensitivity to prolonged LDR-IR through inhibition of homologous recombination (through inhibition of Rad51).

The effect of miniscalpel-needle versus steroid injection for trigger thumb release

This study compared the result of percutaneous release using a miniscalpel-needle and steroid injection in 93 trigger thumbs in 83 patients. The patients were randomly assigned to either miniscalpel-needle percutaneous release (group A) or steroid injection (group B). Visual analogue pain scales and patients' satisfaction were evaluated at baseline, 1 and 12 months. One patient in group A and two patients in group B were lost to follow-up. Forty-four of the 46 trigger thumbs in group A and 12 of 47 trigger thumbs in group B had satisfactory results at 12 months. No digital nerve injury occurred in either group. Percutaneous release with a miniscalpel-needle had a higher success rate than steroid injection.

[The prognosis value of B-type natriuretic peptide testing in critically ill non-cardiogenic patients]

OBJECTIVE

B-type natriuretic peptide (BNP)have been used widely in the diagnosis and prognosis of cardiogenic diseases, but the association between BNP concentrations and non-cardiogenic critical illness is unknown. Our study aims at investigating the role of natriuretic peptide testing for predicting 28-day mortality of non-cardiogenic critically ill patients in emergency department (ED).

METHODS

A total of 255 non-cardiogenic critically ill patients treated in the emergency department were prospectively enrolled and a sample of blood was obtained for BNP measurement from each patient. A variety of clinical and laboratory variables were recorded. After 28 days, the vital status of each patient was ascertained and the association between BNP values at presentation and mortality was assessed.

RESULTS

71 patients died during the 28-day observation period. Median BNP concentrations at presentation among decedents were significantly higher than those of survivors (326.0 ng/L versus 50.9 ng/L, P < 0.001). The optimal BNP cut point for predicting 28-day mortality was 114.0 ng/L. In a multivariate analysis (Cox-regression), a BNP concentration greater than 114.0 ng/L (RR 7.268, 95% CI 3.864-13. 672) and an Acute Physiology and Chronic Health Evaluation II (APACHE II) scores greater than 20 (RR 3.330, 95% CI 1.815-6.109) were the independent predictors of the 28-day mortality. BNP concentration alone had an area under the receiver operating characteristic curve (AUC) of 0.825 for predicting mortality.

CONCLUSIONS

BNP concentrations at presentation are strong predictor of 28-day mortality in patients with non-cardiogenic critically ill patients in ED, which is better than Rapid Acute Physiology Score (RAPS) , Rapid Emergency Medicine Score (REMS) and APACHE II score.

Postsurgical drainage and the risk of breast cancer recurrence in Chinese breast cancer patients

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Background: Clinical investigations suggest that while primary breast cancer surgical removal favorably modifiers the natural history of breast cancer. Postoperative drainage, a surgery-derived discharge after breast cancer surgery, reflecting some biological features of surgical stimulation, was assessed and explored its relationship with breast cancer recurrence in this study. Methods: A total of 1445 women undergoing surgery between Jan 1, 2000 and Dec31, 2002 in Cancer Hospital of Fudan University, Shanghai, China was retrospectively studied. Survival curves were performed with Kaplan-Meier method and the predictive value of postsurgical drainage was estimated using proportional Cox regression model. Conclusions: The larger drainage volume POD 1 is a useful marker, suggesting a greater stimulation to surgical treatment compared to the lower ones. Awareness of the relationship between early surgery-stimulated effects and harmful wound healing response might help to explore new strategies to block or deplete these harmful effects, resulting in improving patients' survival.

No significant financial relationships to disclose.

Purification and cDNA cloning of a cadmium-binding metallothionein from the freshwater crab Sinopotamon henanense

Metallothioneins (MTs) are cysteine-rich, metal-binding proteins that are useful biomarkers for monitoring pollution by heavy metals. In this report, a novel cadmium (Cd)-binding MT (CdMT) from Sinopotamon henanense was purified using acetone precipitation (50-80%), followed by gel-filtration chromatography and anion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and time-of-flight mass spectrometry analysis showed that S. henanense CdMT existed as monomer and dimmer forms, with a monomer molecular weight of 6890 Da and a dimmer molecular weight of 13,766 Da. In addition, the full-length cDNA sequence of S. henanense CdMT was prepared from the gill RNA using reverse transcription-polymerase chain reaction and 3' and 5' rapid amplification of cDNA ends (RACE) methods. Sequence analyses indicated that the isolated cDNA (633 bp) contains an open reading frame of 177 bp that encodes a protein with 59 amino acids. The deduced amino acid sequence has 18 cysteine residues, implying that S. henanense CdMT binds six equivalents of bivalent metal ions (Cd) as opposed to the seven in its mammalian counterparts. The deduced molecular weight of MT without binding metals is 6218 Da. If six bound Cd atoms are counted, the deduced molecular weight of S. henanense CdMT would be 6892 Da, which is very similar to the molecular weight of the purified protein (6890 Da) determined by time-of-flight mass spectrometry analysis. These confirmed our results of MT purification. These present studies will be helpful to increase the database information of heavy-metal-induced MT in terms of crustaceans.

Knockdown of interleukin-2 by shRNA-mediated RNA interference prolongs liver allograft survival

Interleukin-2 (IL-2) plays a central role in T-cell activation, expansion, and homeostasis. The failure of IL-2 biosynthesis may play a critical role in tolerance induction. We tested the effect of IL-2 blockade by short hairpin RNA (shRNA) on regulating acute rejection in rat liver transplantation. To this end, we successfully designed and selected an effective interference plasmid, pIL-2B. The IL-2 mRNA expression level in the pIL-2B group was one-fifth of that in the no transfection group. Lewis to BN orthotopic liver transplant model was used to explore the effect of knockdown IL-2 by shRNA in vivo. Recipients treated with pIL-2-shRNA survived longer (median survival time of 16 d range 7-21 d) than those with empty vector (11; range 5-13) or saline (9; range 5-13) (P<0.05), and was inferior to those with CsA (24; range 13-36, P<0.05). The IL-2-shRNA attenuated acute rejection with decreased apoptosis of hepatocytes and reduced cytokine production of IL-2, tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) in the graft. Our results suggest that IL-2 targeting using RNA interference approach may be of potential interest in organ transplantation.

[Retrospective study of liver failure complicated with bacterium and fungous infection]

OBJECTIVE

To study clinic character of liver failure complicated with bacterium and fungous infection.

METHODS

The patients with liver failure complicated with bacterial and fungous infection who were treated in our hospital from January 1986 to June 2006 were studied. All patients had clinical manifestation and positive of bacterium. The data were statistical analysis.

RESULTS

507 patients diagnosed with fungous infection were found from January 1986 to June 2006 in which 132 patients were diagnosed with bacterial and fungous infection. There were 85 patients (64.39%) with chronic severe hepatitis and 40 patients (30.3%) with decompensation cirrhosis. Bacterial infection happened in 153 cases in which the rate of nosocomial infections was 54.90%. 204 bacterial strains were separated in which 143 strains (70.10%) were gram-negative bacterium and 61 (29.90%) strains were gram-positive bacterium. The main sites of bacterial infection were abdominal cavity (122 cases) and lung (30 cases). Fungous infection happened in 143 cases in which the rate of nosocomial infections was 86.71%. 155 fungous strains were separated in which 90 strains (58.06%) were Candida albicans, 17 strains (10.97%) were Aspergillus fumigatus and 25 (16.13%) strains were non-Candida albicans. The main sites of fouguns infection were lung (94 cases) and mouth (53 cases). 84 patients (63.64%) were ineffective and died after treatment.

CONCLUSION

The patients with decompensation cirrhosis and chronic severe liver hepatitis were easy to be infected by bacterial and fungous. the rate of fungous nosocomial infections is higher than that of bacterium. The prognosis is bad in patients who had secondary fungous infection.

DNA mismatch repair initiates 6-thioguanine--induced autophagy through p53 activation in human tumor cells

PURPOSE

We investigate the roles of DNA mismatch repair (MMR) and p53 in mediating the induction of autophagy in human tumor cells after exposure to 6-thioguanine (6-TG), a chemotherapy drug recognized by MMR. We also examine how activation of autophagy affects apoptosis (type I cell death) after MMR processing of 6-TG.

EXPERIMENTAL DESIGN

Using isogenic pairs of MLH1(-)/MLH1(+) human colorectal cancer cells (HCT116) and MSH2(-)/MSH2(+) human endometrial cancer cells (HEC59), we initially measure activation of autophagy for up to 3 days after 6-TG treatment using LC3, a specific marker of autophagy. We then assess the role of p53 in autophagic signaling of 6-TG MMR processing using both pifithrin-alpha cotreatment to chemically inhibit p53 transcription and small hairpin RNA inhibition of p53 expression. Finally, we use Atg5 small hairpin RNA inhibition of autophagy to assess the effect on apoptosis after MMR processing of 6-TG.

RESULTS

We find that MMR is required for mediating autophagy in response to 6-TG treatment in these human tumor cells. We also show that p53 plays an essential role in signaling from MMR to the autophagic pathway. Finally, our results indicate that 6-TG-induced autophagy inhibits apoptosis after MMR processing of 6-TG.

CONCLUSIONS

These data suggest a novel function of MMR in mediating autophagy after a chemical (6-TG) DNA mismatch damage through p53 activation. The resulting autophagy inhibits apoptosis after MMR processing of 6-TG.

Determining sources of fecal bacteria in waterways

The microbiological contamination of waterways by pathogenic microbes has been, and is still, a persistent public safety concern in the United States and in most countries of the world. As most enteric pathogens are transmitted through the fecal-oral route, fecal pollution is generally regarded as the major contributor of pathogens to waterways. Fecal pollution of waterways can originate from wastewater treatment facilities, septic tanks, domestic- and wild-animal feces, and pets. Because enteric pathogens are derived from human or animal sources, techniques capable of identifying and apportioning fecal sources have been intensively investigated for use in remediation efforts and to satisfy regulatory concerns. Pollution of human origin is of the most concern, since human feces is more likely to contain human-specific enteric pathogens. Fecal indicator bacteria have been used successfully as the primary tool for microbiologically based risk assessment. However measurement of fecal indicator bacteria does not define what pathogens are present, or define the sources of these bacteria. Microbial source tracking (MST) methods that have the ability to differentiate among sources of fecal pollution are currently under development. These methods will ultimately be useful for risk assessment purposes and to aid regulatory agencies in developing strategies to remediate microbiologically impaired waterways.

Prediction of nitrogen excretion in feces and urine of beef cattle offered diets containing grass silage

Data from 286 beef cattle, obtained in total diet digestibility assessments, were used to examine effects of dietary and animal factors on N excretion in feces and urine and to develop prediction equations for N excretion in beef cattle. The animals used were mainly from beef breeds, at various ages (from growth to finishing) and live BW (153 to 580 kg), and offered diets containing grass silage at production feeding levels. Dietary forage proportion ranged from 199 to 1,000 g/kg of DM and dietary CP concentration from 108 to 217 g/kg of DM. Linear and multiple regression techniques were used to examine relationships between the efficiency of N utilization and dietary and animal variables with the experimental effects removed. The statistical analysis indicated that N excretion was related positively (P < 0.001) to live BW and intakes of DM, N, and ME, and negatively (P < 0.001) to dietary forage proportion. The prediction equation for N excretion, developed using N intake alone, produced a large r2 (0.898) and a small SE (12.3). Addition of live BW and forage proportion as supporting predictors to this relationship only marginally increased R2 to 0.915 and reduced SE to 11.2. Nitrogen excretion was less well related to live BW (r2 = 0.771, SE = 18.5) than to N intake. Addition of N intake as a proportion of DMI or ME intake to the relationship between live BW and N excretion increased R2 to 0.824 and reduced SE to 16.2. The internal validation of these equations revealed that using N intake as the primary predictor produced a very accurate prediction of N excretion. In situations where data on N intake are not available, prediction equations based on live BW and dietary N concentration together can produce a relatively accurate assessment of N excretion. A number of mitigation strategies to reduce N excretion in feces and urine in beef cattle are discussed, including manipulation of dietary N concentration, diet quality, and level of feeding. The prediction equations and mitigation strategies developed in the current study provide an approach for beef producers to quantify N excretion against production and to develop their own mitigation strategies to reduce N excretion.

Estrogen Amplifies Pain Responses to Uterine Cervical Distension in Rats by Altering Transient Receptor Potential-1 Function

INTRODUCTION

Estrogen sensitizes responses to painful stimuli, but its contribution to acute and chronic pain from the uterine cervix is unknown. Previous studies link the excitatory transient receptor potiential-1 channel (TRPV-1) to sensitization in viscera, and show that estrogen increases TRPV-1 expression in afferents from the uterine cervix. Here, we tested whether estrogen enhanced responses to uterine cervical distension in rats, and whether this involved TRPV-1 channels.

METHODS

Ovariectomized rats, with or without estrogen replacement, were anesthetized and hypogastric nerve and abdominal muscle contraction reflex responses to graded uterine cervical distension were recorded. Single unit hypogastric nerve fiber firing was measured before and after acute treatment with the TRPV-1 antagonist, capsaizepine, or vehicle.

RESULTS

Abdominal muscle contraction reflex responses to uterine cervical distension were enhanced in estrogen-treated rats. Hypogastric afferent responses to cervical distension were reduced by capsaizepine in estrogen-treated animals, but were unaffected in ovariectomized animals without estrogen replacement.

CONCLUSIONS

These data suggest that the TRPV-1 channel is unimportant for normal mechanosensation in the cervix in the absence of estrogen, since capsaizepine failed to reduce responses to uterine cervical distension in rats without estrogen replacement. In contrast, TRPV-1 function is important for estrogen-induced sensitization. These data raise the possibility that acute and chronic pain coming from the cervix, such as labor or cancer, may be enhanced by estrogen and might be reduced by antagonists of TRPV-1.

[Changes of peripheral plasmacytoid dendritic cells and lymphocyte subsets in chronic hepatitis B patients treated with consensus interferon alpha]

OBJECTIVE

To study the changes of peripheral plasmacytoid dendritic cells and lymphocyte subsets in patients with chronic hepatitis B (CHB) during consensus interferon (CIFN) treatment.

METHODS

Twenty-three patients with CHB were treated with CIFN for 24 weeks and followed up for another 24 weeks. Peripheral plasmacytoid dendritic cells and lymphocyte subsets were measured throughout the treatment and follow-up periods.

RESULTS

After CIFN treatment, 43.5% of the patients had virological and biochemical responses. The percentage and absolute number of peripheral plasmacytoid dendritic cells decreased significantly (P less than 0.05), the number of CD3+ cells, CD4+ T cells, B cells and the ratio of CD4+/CD8+ cells decreased also (P less than 0.05), but the number of CD8+ T cells and NK cells increased (P less than 0.05).

CONCLUSIONS

Consistent virological and biochemical responses can be seen in some patients with CHB virus infection after CIFN treatment, and the percentage and number of their peripheral plasmacytoid dendritic cells greatly decreased, but the number of CD8+ T cells and NK cells increased.

High-throughput and quantitative procedure for determining sources of Escherichia coli in waterways by using host-specific DNA marker genes

Escherichia coli is currently used as an indicator of fecal pollution and to assess water quality. While several genotypic techniques have been used to determine potential sources of fecal bacteria impacting waterways and beaches, they do not allow for the rapid analysis of a large number of samples in a relatively short period of time. Here we report that gene probes identified by Hamilton and colleagues (M. J. Hamilton, T. Yan, and M. J. Sadowsky, Appl. Environ. Microbiol. 72:4012-4019, 2006) were useful for the development of a high-throughput and quantitative macroarray hybridization system to determine numbers of E. coli bacteria originating from geese/ducks. The procedure we developed, using a QBot robot for picking and arraying of colonies, allowed us to simultaneously analyze up to 20,736 E. coli colonies from water samples, with minimal time and human input. Statistically significant results were obtained by analyzing 700 E. coli colonies per water sample, allowing for the analysis of approximately 30 sites per macroarray. Macroarray hybridization studies done on E. coli collected from water samples obtained from two urban Minnesota lakes and one rural South Carolina lake indicated that geese/ducks contributed up to 51% of the fecal bacteria in the urban lake water samples, and the level was below the detection limit in the rural lake water sample. This technique, coupled with the use of other host source-specific gene probes, holds great promise as a new quantitative microbial source tracking tool to rapidly determine the origins of E. coli in waterways and on beaches.

Relationships Among Manure Nitrogen Output and Dietary and Animal Factors in Lactating Dairy Cows

A large data set derived from total diet digestibility assessments on lactating dairy cows (535 Holstein-Friesian and 29 Norwegian) was used to examine effects of dietary and animal factors on manure (feces and urine) nitrogen (N) output and to develop mitigation strategies and prediction equations for manure N output in lactating dairy cows. Manure N output was positively and significantly related to live weight, milk yield, dietary crude protein (CP) concentration, dry matter intake, and N intake. Reducing the dietary CP concentration or increasing the milk yield decreased manure N output per kilogram of milk yield. Prediction equations for manure N output using live weight and milk yield, either alone or combined, had relatively low R2 (0.227 to 0.474) and large standard error (70.6 to 85.6) values. Addition of dietary CP concentration to these relationships considerably increased R2 to 0.754 and reduced the standard error to 48.2. Relating manure N output to N intake produced a very high r2 (0.901) and a very low standard error (30.6). The addition of live weight and milk yield to this relationship as supporting predictors only marginally increased R2 to 0.910 and reduced the standard error to 29.3. The internal validation of these equations revealed that use of N intake as the primary predictor produced a very accurate prediction of manure N output. In situations in which data on N intake are not available, prediction equations based on dietary CP concentration, live weight, and milk yield together can produce a relatively accurate assessment of manure N output.

[Study on the biomechanical behavior of human intestine]

To investigate the biomechanical behavior of human intestines. The tensile test human intestine was performed with the electronic tension machine in this paper. The results indicate that the exponential relationship for the stress-strain of the human intestine was obtained, and the exponential coefficient a of each segment of the intestine is almost the same although the constant C is different. It also shows that the relative rate of stretch length of each segment intestines is different in longitudinal and circumferential directions. And the incremental elastic modulus of colon is less than those of small intestine. It is considered that the colon can be more easily deformed. The experimental results provide the theoretic basis for research on intestinal endoscopic microrobot.

Cladophora (Chlorophyta) spp. harbor human bacterial pathogens in nearshore water of Lake Michigan

Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 x 10(3) cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 x 10(2) Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest that Cladophora is a likely secondary habitat for pathogenic bacteria in Lake Michigan and that the association of these bacteria with Cladophora warrants additional studies to assess the potential health impact on beach users.

Development of goose- and duck-specific DNA markers to determine sources of Escherichia coli in waterways

The contamination of waterways with fecal material is a persistent threat to public health. Identification of the sources of fecal contamination is a vital component for abatement strategies and for determination of total maximum daily loads. While phenotypic and genotypic techniques have been used to determine potential sources of fecal bacteria in surface waters, most methods require construction of large known-source libraries, and they often fail to adequately differentiate among environmental isolates originating from different animal sources. In this study, we used pooled genomic tester and driver DNAs in suppression subtractive hybridizations to enrich for host source-specific DNA markers for Escherichia coli originating from locally isolated geese. Seven markers were identified. When used as probes in colony hybridization studies, the combined marker DNAs identified 76% of the goose isolates tested and cross-hybridized, on average, with 5% of the human E. coli strains and with less than 10% of the strains obtained from other animal hosts. In addition, the combined probes identified 73% of the duck isolates examined, suggesting that they may be useful for determining the contribution of waterfowl to fecal contamination. However, the hybridization probes reacted mainly with E. coli isolates obtained from geese in the upper midwestern United States, indicating that there is regional specificity of the markers identified. Coupled with high-throughput, automated macro- and microarray screening, these markers may provide a quantitative, cost-effective, and accurate library-independent method for determining the sources of genetically diverse E. coli strains for use in source-tracking studies. However, future efforts to generate DNA markers specific for E. coli must include isolates obtained from geographically diverse animal hosts.

Stability in a denitrifying fluidized bed reactor

This study evaluates changes in the microbial community structure and function of a pilot-scale denitrifying fluidized bed reactor during periods of constant operating conditions and periods of perturbation. The perturbations consisted of a shutdown period without feed, two disturbances in which biofilms were mechanically sheared from carrier particles, and a twofold step increase in feed nitrate concentration. In the absence of perturbations, nitrate removal was stable and consistently greater than 99%. The structure and dynamics of the microbial community were studied using cloning and sequencing techniques and terminal restriction fragment length polymorphism (T-RFLP) of the SSU rRNA gene. Under unperturbed operating conditions, stable function was accompanied by high constancy and low variability of community structure with the majority of terminal restriction fragments (T-RFs) appearing throughout operation at consistent relative abundances. Several of the consistently present T-RFs correlated with clone sequences closely related to Acidovorax (98% similarity), Dechloromonas (99% similarity), and Zoogloea (98% similarity), genera recently identified by molecular analyses of similar systems. Significant changes in community structure and function were not observed after the shutdown period. In contrast, following the increase in loading rate and the mechanical disturbances, new T-RFs appeared. After both mechanical disturbances, function and community structure recovered. However, function was much more resilient than community structure. The similarity of response to the mechanical disturbances despite differences in community structure and operating conditions suggests that flexible community structure and potentially the activity of minor members under nonperturbation conditions promotes system recovery.

The reductive dechlorination of 2,3,4,5-tetrachlorobiphenyl in three different sediment cultures: evidence for the involvement of phylogenetically similar Dehalococcoides-like bacterial populations

Anaerobic cultures capable of reductively dechlorinating 2,3,4,5-tetrachlorobiphenyl (CB) were enriched from three different sediments, one estuarine, one marine and one riverine. Two different electron donors were used in enrichments with the estuarine sediment (elemental iron or a mixture of fatty acids). The removal of doubly flanked meta and para chlorines to form 2,3,5-CB and 2,4,5-CB was observed in all cultures. Bacterial community analysis of PCR-amplified 16S rRNA gene fragments revealed different communities in these cultures, with the exception of one common population that showed a high phylogentic relatedness to Dehalococcoides species. No Dehalococcoides-like populations were ever detected in control cultures to which no PCBs were added. In addition, the dynamics of this Dehalococcoides-like population were strongly correlated with dechlorination. Subcultures of the estuarine sediment culture demonstrated that the Dehalococcoides-like population disappeared when dechlorination was inhibited with 2-bromoethanesulfonate or when 2,3,4,5-CB had been consumed. These results provide evidence that Dehalococcoides-like populations were involved in the removal of doubly flanked chlorines from 2,3,4,5-CB. Furthermore, the successful enrichment of these populations from geographically distant and geochemically distinct environments indicates the widespread presence of these PCB-dechlorinating, Dehalococcoides-like organisms.

The effect of varying levels of sodium bicarbonate on polychlorinated biphenyl dechlorination in Hudson River sediment cultures

The addition of different concentrations of sodium bicarbonate had a profound effect on 2,3,4,5-chlorobiphenyl (2,3,4,5-CB) dechlorination in Hudson River sediment cultures. The most extensive dechlorination was observed in cultures to which 100 mg l(-1) bicarbonate was added. Cultures amended with 1000 mg l(-1) bicarbonate had the least extensive dechlorination, with 2,4-CB and 2,5-CB as predominant end-products. A significant loss of total chlorinated biphenyl mass was observed in cultures to which < or = 500 mg l(-1) bicarbonate was added, suggesting that degradation beyond chlorinated biphenyls occurred. The dynamics of acetate formation were different among the treatments, with high acetate concentrations detected throughout the 303-day experiment in cultures to which 1000 mg l(-1) bicarbonate had been added. Sodium bicarbonate addition also had a significant impact on bacterial community structure as detected by polymerase chain reaction-denaturant gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene fragments. Three putative polychlorinated biphenyl (PCB) dechlorinators were identified; one Dehalococcoides-like population was detected in all enrichment cultures, whereas two Dehalobacter-like populations were only detected in the enrichment cultures with the most extensive dechlorination. These results suggest that the availability of bicarbonate, and potentially sodium, may affect PCB dechlorination in Hudson River sediment and thus need to be taken into consideration when assessing the fate of PCBs or implementing bioremediation.

The effect of varying levels of sodium bicarbonate on polychlorinated biphenyl dechlorination in Hudson River sediment cultures

The addition of different concentrations of sodium bicarbonate had a profound effect on 2,3,4,5-chlorobiphenyl (2,3,4,5-CB) dechlorination in Hudson River sediment cultures. The most extensive dechlorination was observed in cultures to which 100 mg l(-1) bicarbonate was added. Cultures amended with 1000 mg l(-1) bicarbonate had the least extensive dechlorination, with 2,4-CB and 2,5-CB as predominant end-products. A significant loss of total chlorinated biphenyl mass was observed in cultures to which < or = 500 mg l(-1) bicarbonate was added, suggesting that degradation beyond chlorinated biphenyls occurred. The dynamics of acetate formation were different among the treatments, with high acetate concentrations detected throughout the 303-day experiment in cultures to which 1000 mg l(-1) bicarbonate had been added. Sodium bicarbonate addition also had a significant impact on bacterial community structure as detected by polymerase chain reaction-denaturant gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene fragments. Three putative polychlorinated biphenyl (PCB) dechlorinators were identified; one Dehalococcoides-like population was detected in all enrichment cultures, whereas two Dehalobacter-like populations were only detected in the enrichment cultures with the most extensive dechlorination. These results suggest that the availability of bicarbonate, and potentially sodium, may affect PCB dechlorination in Hudson River sediment and thus need to be taken into consideration when assessing the fate of PCBs or implementing bioremediation.

A proposed staging system for diffuse malignant peritoneal mesothelioma patients undergoing cytoreductive surgery and perioperative intraperitoneal chemotherapy

4150

Background: There is no staging system available for diffuse malignant peritoneal mesothelioma (DMPM). This study evaluated seven clinical, seven radiological and twelve histopathologic prognostic parameters for survival of patients with DMPM. Methods: Between September 1989 and September 2005, sixty-two DMPM patients who were treated in a uniform fashion utilizing cytoreductive surgery combined with heated intraoperative intraperitoneal chemotherapy, with cisplatin and doxorubicin, followed by early postoperative intraperitoneal paclitaxel from postoperative day 1 to day 5 were included in this study. All prognostic parameters were analyzed in univariate and multivariate analyses using overall survival as the endpoint. The clinical and radiological data were obtained prospectively. A review of the histopathological features of DMPM was performed by two experienced pathologists, who individually evaluated each case. The mean number of specimens taken from separate anatomic sites was 11 ± 4 per patient. The mean number of slides studied was 20 ± 8 per patient. Results: The median follow-up was 37 months (range 8 to 143 months). The overall survival was 79 months (range 1 to 143 months) and 5-year survival was 50%. The following 14 prognostic variables were significant for survival in the univariate analysis: gender (p = 0.045), peritoneal cancer index (p = 0.038), completeness of cytoreduction score (p = 0.010), interpretive CT findings of the small bowel (p = 0.001), histologic type (p < 0.001), nuclear size (p < 0.001), nuclear/cytoplasmic ratio (p < 0.001), mitotic count (p < 0.001), atypical mitosis (p < 0.001), chromatin pattern (p < 0.001), cellular necrosis (p < 0.001), perineural invasion (p = 0.037), stroma pattern (p < 0.001) and depth of invasion (p = 0.014). In the multivariate analysis, the only factor that was independently associated with an improved survival was nuclear size. The 3-year survival rates with nuclear size of 10–20 μm, 21–30 μm, 31–40 μm and > 40 μm were 100%, 87%, 27% and 0%, respectively. Conclusions: Nuclear size was the dominant factor determining overall survival in patients with DMPM. A histopathological staging system based on measurement of the nuclear size was proposed.

No significant financial relationships to disclose.

Small Intestinal Submucosa Improves Islet Survival and Function in Vitro Culture

INTRODUCTION

Most centers maintain isolated human islet preparations in tissue culture to improve the safety as well as the practicality of islet transplantation. However, maintaining viability and recovery of islets remains a challenge. Extracellular matrix (ECM) is one of the most important components of the islet microenvironment. Reconstruction of the cell-matrix relationship seems to be necessary to sustain the structure and function of differentiated islets. Small intestinal submucosa (SIS), a natural ECM, is well known to promote wound healing, tissue remodeling, and cell growth. The purpose of this study was to evaluate recovery and function of isolated rat pancreatic islets during in vitro culture with SIS.

METHODS

Pancreatic islets isolated from Wistar rats following intraductal collagenase distension, mechanical dissociation, and EuroFicoll purification were cultured in plates coated with multilayer SIS (SIS-treated group) or without (standard cultured group) for 7 or 14 days in an islet culture media of RPMI 1640 (Gibco). The islets from both experimental groups were stained and counted with dithizone. Islet recovery following culture was determined by the ratio of counts after culture to the yield of islets immediately following islet isolation. The viability of the islets was assessed by a glucose challenge test with low glucose (2.7 mmol/L), high glucose (16.7 mmol/L), and high glucose solution supplemented with 50 micromol/L 3-isobutyl-1-methylxanthine solution. The apoptosis of islet cells was measured by relative quantification of histone-complexed DNA fragments by using enzyme-linked immunosorbent assay.

RESULTS

After 7 or 14 days of in vitro tissue culture, the recovery in SIS-treated islets group was about double of that cultured in the plates without SIS coating. In the SIS-treated group, there was no significant difference between the short- and the long-term periods of culture (95.8%+/-1.0% vs 90.8%+/-1.5%, P>.05). Following incubation with high glucose (16.7 mmol/L) solution, the insulin secretion in the SIS-treated group showed a greater increase than the control group after 14 days of culture (20.7+/-1.1 mU/L vs 11.8+/-1.1 mU/L, P<.05). When islets were placed in the high glucose solution containing IBMX, the stimulated insulin secretion was more increased in the SIS-treated than in the control group despite the duration of the culture. The calculated stimulation index of SIS-treated group was about two to three times greater than the control group. In addition, the stimulation index of the SIS-treated group remained constant regardless of short-term versus long-term culture (9.5+/-0.2 vs 10.2+/-1.2, P>.05). Much less apoptosis of islet cells occurred in the SIS-treated than in the control group.

CONCLUSION

Coculture of isolated rat islets with native sheetlike small intestinal submucosa seemed to build an ECM for islets providing possible biotrophic and growth factors that promote the recovery and subsequent function of islets.

Methoxyamine potentiates iododeoxyuridine-induced radiosensitization by altering cell cycle kinetics and enhancing senescence

We previously reported that methoxyamine (an inhibitor of base excision repair) potentiates iododeoxyuridine (IUdR)-induced radiosensitization in human tumor cells. In this study, we investigated the potential mechanisms of this enhanced cell death. Human colorectal carcinoma RKO cells were exposed to IUdR (3 micromol/L) and/or methoxyamine (3 mmol/L) for 48 hours before ionizing radiation (5 Gy). We found that IUdR/methoxyamine altered cell cycle kinetics and led to an increased G1 population but a decreased S population before ionizing radiation. Immediately following ionizing radiation (up to 6 hours), IUdR/methoxyamine-pretreated cells showed a stringent G1-S checkpoint but an insufficient G2-M checkpoint, whereas a prolonged G1 arrest, containing 2CG1 and 4CG1 cells, was found at later times up to 72 hours. Levels of cell cycle-specific markers [p21, p27, cyclin A, cyclin B1, and pcdc2(Y15)] and DNA damage signaling proteins [gammaH2AX, pChk1(S317), and pChk2(T68)] supported these altered cell cycle kinetics. Interestingly, we found that IUdR/methoxyamine pretreatment reduced ionizing radiation-induced apoptosis. Additionally, the extent of cell death through necrosis or autophagy seemed similar in all (IUdR +/- methoxyamine + ionizing radiation) treatment groups. However, a larger population of senescence-activated beta-galactosidase-positive cells was seen in IUdR/methoxyamine/ionizing radiation-treated cells, which was correlated with the increased activation of the senescence factors p53 and pRb. These data indicate that IUdR/methoxyamine pretreatment enhanced the effects of ionizing radiation by causing a prolonged G1 cell cycle arrest and by promoting stress-induced premature senescence. Thus, senescence, a novel ionizing radiation-induced tumor suppression pathway, may be effectively targeted by IUdR/methoxyamine pretreatment, resulting in an improved therapeutic gain for ionizing radiation.

Phylogenetic and functional biomakers as indicators of bacterial community responses to mixed-waste contamination

Few studies have demonstrated changes in community structure along a contaminant plume in terms of phylogenetic, functional, and geochemical changes, and such studies are essential to understand how a microbial ecosystem responds to perturbations. Clonal libraries of multiple genes (SSU rDNA, nirK, nirS, amoA, pmoA, and dsrAB) were analyzed from groundwater samples (n = 6) that varied in contaminant levels, and 107 geochemical parameters were measured. Principal components analyses (PCA) were used to compare the relationships among the sites with respect to the biomarker (n = 785 for all sequences) distributions and the geochemical variables. A major portion of the geochemical variance measured among the samples could be accounted for by tetrachloroethene, 99Tc, No3, SO4, Al, and Th. The PCA based on the distribution of unique biomarkers resulted in different groupings compared to the geochemical analysis, but when the SSU rRNA gene libraries were directly compared (deltaC(xy) values) the sites were clustered in a similar fashion compared to geochemical measures. The PCA based upon functional gene distributions each predicted different relationships among the sites, and comparisons of Euclidean distances based upon diversity indices for all functional genes (n = 432) grouped the sites by extreme or intermediate contaminant levels. The data suggested that the sites with low and high perturbations were functionally more similar than sites with intermediate conditions, and perhaps captured the overall community structure better than a single phylogenetic biomarker. Moreover, even though the background site was phylogenetically and geochemically distinct from the acidic sites, the extreme conditions of the acidic samples might be more analogous to the limiting nutrient conditions of the background site. An understanding of microbial community-level responses within an ecological framework would provide better insight for restoration strategies at contaminated field sites.

Effects of Dairy Cow Genotype with Two Planes of Nutrition on Energy Partitioning Between Milk and Body Tissue

The data used in the present study were derived from a 2 (genotype) x 2 (plane of nutrition) factorial design production study using Holstein-Friesian (n = 32) and Norwegian (n = 32) first-lactation dairy cattle offered grass silage-based diets from 1 to 44 wk of lactation. The high nutrition diet had concentrate inclusions (g/kg of dry matter) of 600, 500, and 400 for lactation days of < 101, 101 to 200, and > 200, respectively, and the low nutrition diet included concentrates at 300, 200, and 100 for the same periods. Dietary metabolizable energy (ME) concentrations were measured in calorimetric chambers at lactation d 80, 160, and 240 respectively, and then applied to production data to calculate ME intake. From wk 1 to 44 of lactation, Holstein-Friesian cows had a consistently lower accumulated live weight gain and body condition score, and a consistently higher ME intake and milk energy output than Norwegian cows, irrespective of the plane of nutrition. Compared with Norwegian cows using mean data derived from the 2 planes of nutrition, Holstein-Friesian cows produced a significantly higher proportion of milk energy output over ME intake in early and mid lactation, although this increase was not significant in late lactation. In contrast, Holstein-Friesian cows partitioned a significantly lower proportion of ME intake into body tissue than Norwegian cows in early lactation, although the differences were not significant in mid or late lactation. When ME intake and energy used for maintenance, milk, and body tissue were taken into account, the efficiency of ME use for lactation was similar between the 2 genotypes offered the high or low concentrate diet during the whole lactation. It is concluded that Holstein-Friesian cows can produce more milk energy than Norwegian cows, mainly as a result of higher ME intake and because of a greater ability to partition more energy into milk and less into body tissue. The effect on energy partitioning mainly occurs in early and midlactation and is particularly evident with high concentrate diets.

Schedule-dependent drug effects of oral 5-iodo-2-pyrimidinone-2'-deoxyribose as an in vivo radiosensitizer in U251 human glioblastoma xenografts

PURPOSE

5-Iodo-2-pyrimidinone-2'-deoxyribose (IPdR) is an oral prodrug of 5-iodo-2'-deoxyuridine (IUdR), an in vitro/in vivo radiosensitizer. IPdR can be rapidly converted to IUdR by a hepatic aldehyde oxidase. Previously, we found that the enzymatic conversion of IPdR to IUdR could be transiently reduced using a once daily (q.d.) treatment schedule and this may affect IPdR-mediated tumor radiosensitization. The purpose of this study is to measure the effect of different drug dosing schedules on tumor radiosensitization and therapeutic index in human glioblastoma xenografts.

EXPERIMENTAL DESIGN

Three different IPdR treatment schedules (thrice a day, t.i.d.; every other day, q.o.d.; every 3rd day, q.3.d.), compared with a q.d. schedule, were analyzed using athymic nude mice with human glioblastoma (U251) s.c. xenografts. Plasma pharmacokinetics, IUdR-DNA incorporation in tumor and normal proliferating tissues, tumor growth delay following irradiation, and body weight loss were used as end points.

RESULTS

The t.i.d. schedule with the same total daily doses as the q.d. schedule (250, 500, or 1,000 mg/kg/d) improved the efficiency of IPdR conversion to IUdR. As a result, the percentage of IUdR-DNA incorporation was higher using the t.i.d. schedule in the tumor xenografts as well as in normal small intestine and bone marrow. Using a fixed dose (500 mg/kg) per administration, the q.o.d. and q.3.d. schedules also showed greater IPdR conversion than the q.d. schedule, related to a greater recovery of hepatic aldehyde oxidase activity prior to the next drug dosing. In the tumor regrowth assay, all IPdR treatment schedules showed significant increases of regrowth delays compared with the control without IPdR (q.o.d., 29.4 days; q.d., 29.7 days; t.i.d., 34.7 days; radiotherapy alone, 15.7 days). The t.i.d. schedule also showed a significantly enhanced tumor growth delay compared with the q.d. schedule. Additionally, the q.o.d. schedule resulted in a significant reduction in systemic toxicity.

CONCLUSIONS

The t.i.d. and q.o.d. dosing schedules improved the efficiency of enzymatic activation of IPdR to IUdR during treatment and changed the extent of tumor radiosensitization and/or systemic toxicity compared with a q.d. dosing schedule. These dosing schedules will be considered for future clinical trials of IPdR-mediated human tumor radiosensitization.

The Interaction between Two Radiosensitizers: 5-Iododeoxyuridine and Caffeine

5-Iododeoxyuridine (IUdR) and caffeine are recognized as potential radiosensitizers with different mechanisms of interaction with ionizing radiation (IR). To assess the interaction of these two types of radiosensitizers, we compared treatment responses to these drugs alone and in combination with IR in two p53-proficient and p53-deficient pairs of human colon cancer cell lines (HCT116 versus HCT116 p53-/- and RKO versus RKO E6). Based on clonogenic survival, the three single agents (IR, IUdR, and caffeine) as well as IUdR or caffeine combined with IR are less or equally effective in p53-deficient human tumor cells compared with p53-proficient tumor cells. However, using both radiosensitizers, a significantly greater radiosensitization was found in p53-deficient human tumor cells. To better understand the interaction of these two radiosensitizers, additional studies on DNA repair and cell cycle regulation were done. We found that caffeine enhanced IUdR-DNA incorporation and IUdR-mediated radiosensitization by partially inhibiting repair (removal) of IUdR in DNA. The repair of IR-induced DNA double-strand breaks was also inhibited by caffeine. However, these effects of caffeine on IUdR-mediated radiosensitization were not found in p53-proficient cells. Cell cycle analyses also showed a greater abrogation of IR-induced S- and G2-phase arrests by caffeine in p53-deficient cells, particularly when combined with IUdR. Collectively, these data provide the mechanistic bases for combining these two radiosensitizers to enhance tumor cytotoxicity. This differential dual mode of radiosensitization by combining IUdR and caffeine-like drugs (e.g., UCN-01) in p53-deficient human tumors may lead to a greater therapeutic gain.

The Impact of Sediment Characteristics on PCB-dechlorinating Cultures: Implications for Bioaugmentation

PCB-dechlorinating cultures with complimentary activities, previously derived from estuarine Baltimore Harbor (B), marine Palos Verdes (P) and riverine Hudson River (H) sediments, were mixed and then inoculated into sterile sediments from the same sources. In the treatments containing sterile B sediment, the different inocula had limited impact on the bacterial community development and on dechlorination patterns, all of which were similar. In treatments containing sterile P or H sediment, however, different inocula resulted in significantly different PCB dechlorination patterns and bacterial communities. The B sediment appeared to support not only the most extensive and rapid dechlorination of the three sediments, but also supported a more diverse bacterial community. This was thought to be a result of nutritional richness, as it was high in organic carbon and micronutrients such as zinc and cobalt. Although mixing three PCB-dechlorinating cultures was able to produce a culture capable of enhanced PCB-dechlorinating activity as compared to single cultures, some activities were lost upon culture transfer. This indicates that care must be taken to establish robust PCB-dechlorinating cultures capable of extensive dechlorination prior to pursuing bioaugmentation. In addition, our results indicate that the concentration and availability of macro- and micro-nutrients could have a significant impact on the microbial community structure, and thus a thorough characterization of the sediment at contaminated sites is essential for implementing bioaugmentation for PCB bioremediation.

[Study on spectral behavior of trimethoxyphenylflurone with cadmium in microemulsion]

In the present paper, the spectral behavior of cadmium with trimethoxyphenylflurone (TM-PF) in microemulsion was studied. In the buffer medium of borax-NaOH at pH 10.40, cadmium (II) reacts with TM-PF to form a stable 1:2 complex. Its apparent molar absorptivity is 6.10 x 10(4) L x mol(-1) x cm(-1) at 560 nm. Beer's law is obeyed in the range of 0-0.60 microg x mL(-1). The coexistent metal ions can be separated, and cadmium can be enriched by sulfhydryl dextrane gel (SDG), greatly improving the selectivity and sensibility of the system. The method possesses high sensitivity as well as h igh selectivity, and can be used to determine trace amount of cadmium in environmental samples successfully.

[Application of chemical ecology in controlling marine fouling organisms]

Many marine organisms can produce secondary metabolites beneficial to the protection of marine environments against fouling, and thus, applying chemo-ecological methods to extract the natural antifoulants from marine organisms to resolve the problems relevant to marine fouling is a new thinking in resent years. Its aim is to search for high efficient and non-toxic antifoulants to replace the existing chemically synthetic ones which are unfortunately found to have widespread toxic effects on marine environment. Although we know few about the antifouling mechanisms of secondary metabolites, many natural products have been proved to have antifouling activity. Therefore, basic and applied researches on the ecological roles of these natural compounds, their action mechanisms, coating compatibility, controlled release, and field test are required in the future.

Confidence intervals of similarity values determined for cloned SSU rRNA genes from environmental samples

The goal of this research was to investigate the influence of the error rate of sequence determination on the differentiation of cloned SSU rRNA gene sequences for assessment of community structure. SSU rRNA cloned sequences from groundwater samples that represent different bacterial divisions were sequenced multiple times with the same sequencing primer. From comparison of sequence alignments with unedited data, confidence intervals were obtained from both a 'double binomial' model of sequence comparison and by non-parametric methods. The results indicated that similarity values below 0.9946 are likely derived from dissimilar sequences at a confidence level of 0.95, and not sequencing errors. The results confirmed that screening by direct sequence determination could be reliably used to differentiate at the species level. However, given sequencing errors comparable to those seen in this study, sequences with similarities above 0.9946 should be treated as the same sequence if a 95% confidence is desired.