A retrospective observational study of patients with dilated cardiomyopathy undergoing non-cardiac surgery.

The perioperative risks and factors associated with adverse cardiac outcomes in patients with dilated cardiomyopathy undergoing non-cardiac surgery are unknown. Interrogation of the Nelson Hospital transthoracic echocardiogram database identified 127 patients with dilated cardiomyopathy who satisfied the study criteria and underwent non-cardiac surgery between June 1999 and July 2013. Demographic and clinical data along with postoperative death within 30 days or a major adverse cardiac event were retrieved and analysed. The mean age was 75.9 years. Seventy-one percent of the patients had severe impairment of left ventricular function and 35% had a severely dilated left ventricle. A major adverse cardiac event occurred in 18.1% of patients and 5.5% of patients died within 30 days of surgery. Increased surgical risk and absence of cerebrovascular disease were associated with adverse outcome (P <0.001, P <0.05, respectively). Forty-three and a half percent (43.5%) of patients undergoing high-risk surgery had an adverse outcome compared to 36.1% and 5.9% for moderate and low-risk surgery, respectively. A major adverse cardiac event was observed in 26.7% of patients with cardiovascular disease compared to 9.8% of patients without cardiovascular disease. We were unable to exclude an influence of other potential risk factors due to the retrospective observational nature of the study. These findings highlight a potential increase in complications with moderate or high surgical risk, whilst are reassuring in demonstrating the relative safety of low-risk surgery in this group of high-risk patients.

Evidence for sex ratio distortion by a new microsporidian parasite of a Corophiid amphipod.

In this paper, we describe the occurrence of a microsporidian parasite in female-biased populations of an intertidal amphipod, Corophium volutator (Pallas), at mudflat sites in the Bay of Fundy, Canada. Sequence data for the parasite's 16S rDNA indicate that it is a novel microsporidian species. This parasite was found principally in female host gonads, indicating that it might be a vertically transmitted, sex-distorting microparasite. At 4 sites each sampled in early and mid-summer, parasite prevalence varied from 0 to 21%. In the lab, infected mothers gave rise to more female-biased broods, than did uninfected mothers. Infection was not associated with size of females or with lowered survivorship of their young. Surprisingly, infected mothers actually had higher fertility controlling for body length than did uninfected mothers. Taken together, our results suggest that this novel microsporidian is likely a feminizing microparasite and is a contributing factor to local and widespread sex ratio distortion in C. volutator.

Population densities of corn flea beetle (Coleoptera: Chrysomelidae) and incidence of Stewart's wilt in sweet corn.

To quantify populations of the corn flea beetle, Chaetocnema pulicaria Melsheimer (Coleoptera: Chrysomelidae), and refine estimates of a threshold for its control to prevent Stewart's wilt caused by Erwinia stewartii, sequential plantings of 'Jubilee' sweet corn were made at 2-wk intervals from April or May through August or September 2001 and 2002 at four locations from southern to northern Illinois: Simpson, Brownstown, Champaign, and Mendota. Densities of C. pulicaria and incidence of Stewart's wilt were monitored weekly. At Mendota, where C. pulicaria populations were decimated by cold temperatures during winter 2000-2001, densities reached 33.3 beetles per 15-cm yellow sticky trap per day by September 2002, after a mild 2001-2002 winter. Maximum incidence of Stewart's wilt in single plots at Simpson, Brownstown, Champaign, and Mendota was 22, 36, 39, and 2%, respectively, in 2001, and 33, 47, 99, and 87%, respectively, in 2002. In 24 plots where beetle densities were < or =2 per trap per day, Stewart's wilt incidence was <5% in 20 plots. We propose that two corn flea beetles per trap per day be used as a threshold for insecticide application to seedlings to control C. pulicaria and minimize subsequent incidence of Stewart's wilt in processing sweet corn. Enzyme-linked immunosorbent assays indicated that E. stewartii incidence in C. pulicaria peaked at 67, 62, and 54%, respectively, at Simpson, Brownstown, and Champaign, in 2001, and at 71, 76, and 60%, respectively, in 2002. Further studies might allow the use of areawide or field-specific estimates of E. stewartii incidence in corn flea beetles for adjusting management decisions.

Consequences of the inhibition of Hdm2 expression in human osteosarcoma cells using antisense oligonucleotides.

The present study was performed to identify a potent and sequence-specific antisense oligonucleotide (ASO), to inhibit Hdm2 expression in human cancer cell lines and to study the downstream consequences. Ten chimeric 2'-O-methoxyethyl (MoE)-modified hemimers were synthesized that targeted various regions from the 5'- to the 3'-end of Hdm2 mRNA. The IC50 of the most potent ASO, NCH-4401, was subsequently determined and compared to the IC50 of a 2'-MoE-modified ASO, with a complete phosphorothioate backbone (NCH-4668), and to a 3 bp mismatched ASO (NCH4529). NCH4401 inhibited Hdm2 expression in SJSA-1 cells with an IC50 of 120 nm, whereas NCH-4668 was less potent with an IC50 of 180 nm. The mismatched control ASO was completely inactive, indicating a sequence-dependent mechanism of action of NCH-4401. NCH4401 was subsequently used to study the consequences of inhibiting Hdm2 expression in human osteosarcoma cells. NCH-4401 completely inhibited Hdm2 protein expression in SJSA-1 cells at a concentration of 300 nm, already 4 h after start of ASO treatment. At an ASO concentration of 300 nM, p53 protein was induced 12.5-fold and p21 was induced 8-fold over background levels, 24 h after start of ASO treatment. The dramatic induction of p53 in SJSA-1 cells prompted us to investigate whether the accumulation of p53 in these cells was followed by induction of apoptosis. However, no signs for apoptosis were detected in SJSA-1 cells, following induction of wild-type p53 using the Yopro method and the induction of caspase-3 activity. SJSA-1 cells were subsequently treated with NCH-4401 at different concentrations in combination with two well-known DNA-damaging agents, i.e. carboplatin and mitomycin C. Apoptosis induction following treatment of cells with DNA-damaging agents and NCH4401 was determined in parallel by measuring caspase-3 activation and uptake of the DNA dye Yopro. Carboplatin and mitomycin C together only slightly induced apoptosis in SJSA-1 cells to a factor of approximately 2-fold, as measured by the induction of caspase-3 activity. The downregulation of Hdm2 expression by NCH4401 did not induce apoptosis on its own and did not potentiate the mitomycin C/carboplatin-induced programmed cell death.

Outbreak of Salmonella serotype Hartford infections associated with unpasteurized orange juice.

CONTEXT: Acidic foods such as orange juice have been thought to be unlikely vehicles of foodborne illness. OBJECTIVE: To investigate an outbreak of Salmonella enterica serotype Hartford (Salmonella Hartford) infections among persons visiting a theme park in Orlando, Fla, in 1995. DESIGN: Review of surveillance data, matched case-control study, laboratory investigation, and environmental studies. SETTING: General community. PARTICIPANTS: The surveillance case definition was Salmonella Hartford or Salmonella serogroup C1 infection in a resident of or a visitor to Orlando in May or June 1995. In the case-control study, case patients were limited to theme park hotel visitors and controls were matched to case patients by age group and hotel check-in date. MAIN OUTCOME MEASURES: Risk factors for infection and source of implicated food. RESULTS: Sixty-two case patients from 21 states were identified. Both Salmonella Hartford and Salmonella enterica serotype Gaminara (Salmonella Gaminara) were isolated from stool samples of 1 ill person. Thirty-two case patients and 83 controls were enrolled in the case-control study. Ninety-seven percent of case patients had drunk orange juice in the theme park vs 54% of controls (matched odds ratio, undefined; 95% confidence interval, 5.2 to undefined). The orange juice was unpasteurized and locally produced. Salmonella Gaminara was isolated from 10 of 12 containers of orange juice produced during May and July, indicating ongoing contamination of juice probably because of inadequately sanitized processing equipment. CONCLUSIONS: Unpasteurized orange juice caused an outbreak of salmonellosis in a large Florida theme park. All orange juice was recalled and the processing plant closed. Pasteurization or other equally effective risk-management strategies should be used in the production of all juices.

Acid-base chemical mechanism of aspartase from Hafnia alvei.

An acid-base chemical mechanism is proposed for Hafnia alvei aspartase in which a proton is abstracted from C-3 of the monoanionic form of L-aspartate by an enzyme general base with a pK of 6.3-6.6 in the absence and presence of Mg2+. The resulting carbanion is presumably stabilized by delocalization of electrons into the beta-carboxyl with the assistance of a protonated enzyme group in the vicinity of the beta-carboxyl. Ammonia is then expelled with the assistance of a general acid group that traps an initially expelled NH3 as the final NH4+ product. In agreement with the function of the general acid group, potassium, an analog of NH4+, binds optimally when the group is unprotonated. The pK for the general acid is about 7 in the absence of Mg2+, but is increased by about a pH unit in the presence of Mg2+. Since the same pK values are observed in the pKi(succinate) and V/K pH profile, both enzyme groups must be in their optimum protonation state for efficient binding of reactant in the presence of Mg2+. At the end of a catalytic cycle, both the general base and general acid groups are in a protonation state opposite that in which they started when aspartate was bound. The presence of Mg2+ causes a pH-dependent activation of aspartase exhibited as a partial change in the V and V/Kasp pH profiles. When the aspartase reaction is run in D2O to greater than 50% completion no deuterium is found in the remaining aspartate, indicating that the site is inaccessible to solvent during the catalytic cycle.

Production of an isonitrile antibiotic by an UV-induced mutant of Trichoderma harzianum.

Production of the antibiotic, homothallin II, by a UV-induced mutant strain of Trichoderma harzianum is reported, the wild-type parent of which was not an isonitrile antibiotic-producer. The compound has broad antibiotic activity against Oomycete, Ascomycete and Basidiomycete fungi, and both Gram-positive and -negative bacteria. The significance of the induction of homothallin II is discussed.

The secretory antibody response of inbred lines of chicken to avian infectious bronchitis virus infection.

Two-week-old chicks of a line highly resistant (line C) or highly susceptible (line 151) to infectious bronchitis virus (IBV) were inoculated with the Massachusetts-41 strain of IBV. Tracheal washings, saliva, lachrymal fluid and serum were collected at intervals after inoculation and titrated for their antibody content using neutralization tests and ELISAs. There was no marked difference in antibody concentrations in tracheal washings of the two lines, nor in neutralizing antibody or IBV-specific IgG titres in serum or respiratory tract secretions. However, more IBV-specific IgA was detected in both saliva and lachrymal fluid of the line C chicks following either intranasal or eyedrop inoculation. The different IgA response in lachrymal fluid, but not saliva, was also observed in another pair of inbred chicken lines of different susceptibility to IBV infection, namely lines 6, and 7(2).

Effect of ultraviolet-induced mutants of Trichoderma harzianum with altered antibiotic production on selected pathogens in vitro.

Mutants of Trichoderma harzianum with altered antibiotic production were isolated using ultraviolet light mutagenesis. These included strains whose activity in a Fusarium oxysporum spore germination assay was greater than twice that of the parental strain and one that had no detectable antifungal activity. Characterisation of extracellular metabolites of these strains using thin-layer chromatography and gas-liquid chromatography showed that the strains with high activity produced only elevated levels of a 6-n-pentyl pyrone, the antibiotic produced by the parental strain, but two new antifungal compounds. One of these has been identified as an isonitrile antibiotic. The nature of the interactions of the mutants with Fusarium oxysporum, Rhizoctonia solani, and Pythium ultimum was examined in an in vitro dual-plating assay using two media. High antibiotic production by two T. harzianum strains, BC10 and BC63, did increase inhibition of hyphal growth of R. solani and P. ultimum, but there was no correlation between increased antibiotic production and colonisation ability. In some cases the increased antibiotic levels appeared to impede colonisation of F. oxysporum and R. solani by the mutants. Slow growth rate also affected colonising ability. The types of interactions showed great variability depending on the nature of the T. harzianum isolate and on the test fungus.

The regulation of porin expression in Escherichia coli: effect of turgor stress.

The OmpF and OmpC porins are major outer membrane proteins of Escherichia coli. Their expression is affected by medium osmolarity such that OmpF is normally produced at low osmolarity and OmpC at high osmolarity. Potassium ion accumulation is a major means by which cells maintain their internal osmolarity in high osmolarity medium in the absence of organic osmolytes such as glycine-betaine. Starvation for potassium causes cells to become turgor stressed. The effect of turgor stress and potassium ion concentration on OmpF and OmpC expression was examined. It was found that ompF gene expression was switched off by turgor stress but there was no concomitant increase in OmpC. Instead, ompC expression responded to the accumulation of potassium ions by the cell in high osmolarity medium.

Osmotic regulation of porin expression: a role for DNA supercoiling.

The OmpC and OmpF porins are major outer membrane proteins of Escherichia coli and Salmonella typhimurium. Their expression is affected by many environmental factors and by mutations in a variety of independent genes. The pair of regulatory proteins, OmpR and EnvZ, are required for normal porin expression. Despite intensive investigation, the mechanisms by which porin expression is regulated remain unclear. Mutations which alter supercoiling, as well as inhibitors of DNA gyrase, show that porin expression is extremely and specifically sensitive to the level of DNA supercoiling. Our data lead us to suggest that environmentally induced changes in DNA supercoiling may play a role in determining the level of porin expression. These findings have implications for current models of porin regulation.

OmpR and EnvZ are pleiotropic regulatory proteins: positive regulation of the tripeptide permease (tppB) of Salmonella typhimurium.

The tppB locus of Salmonella typhimurium encodes the anaerobically-induced tripeptide permease. We have demonstrated that expression of tppB requires the function of the ompR and envZ gene products, originally identified as positive regulatory proteins required for the osmotic regulation of porin expression. Significantly, tppB expression is not osmotically regulated. We have also identified three additional genes whose expression depends on OmpR. Thus OmpR and EnvZ serve a more general regulatory role than has previously been supposed. This study provides the first detailed genetic analysis of the ompB locus of S. typhimurium.

In vivo isotype regulation of humoral responses to dextran B1355 in BALB/c mice. Double-class IgG3/IgM producers as a function of age.

This report shows that, in 8- to 10-month-old BALB/c mice immunized intraperitoneally with dextran B1355, approximately 75% of IgG3 anti-alpha (1----3) polyglucan (anti-dex) plaque-forming cells (PFC) detected in the spleen were identified as double-Ig class producers secreting simultaneously IgG3 and IgM antibodies with the same specificity for the dex epitope. Under the same conditions of immunization, however, IgA anti-dex PFC were mostly single-class secretors. IgA PFC developed in the spleen in highest numbers (equal to IgM), but in Peyer's patches IgA PFC were sevenfold more numerous than IgM. Furthermore, spleen IgG3 anti-dex PFC responses were low compared with spleen IgA and IgM anti-dex PFC responses and appeared only late in ontogeny. The possibility is discussed whether a TH dependence of the IgA anti-dex response and a TH-independent generation of the IgG3 response are responsible for the different pattern of isotype expression.

Isolation and characterization of measles virus intracellular nucleocapsid RNA.

Protocols have been established for the preparation of large amounts of pure measles virus intracellular nucleocapsids. As a result, it has been possible to routinely achieve nucleocapsid RNA yields of approximately 200 micrograms (from approximately 5 X 10(8) infected cells). Electrophoretic analysis of this RNA under denaturing conditions revealed a single species whose mass was estimated at approximately 4.8 X 10(6) daltons. Electron microscopic assessment of nucleocapsid RNA contour lengths corroborated the electrophoretic size determination. Total nucleocapsid RNA was shown to contain both negative- and positive-stranded species distributed in a ratio of 2 to 3 genome polarity molecules for each antigenome RNA. Hybridization studies established that all of the virus-specified polyadenylated RNAs were encoded by the negative-stranded nucleocapsid RNA and, therefore, that this nucleocapsid RNA was the measles genome. Examination of the measles virus-specified, polyadenylated transcription products by HCHO-agarose gel electrophoresis revealed at least nine distinct RNA species (rather than the six predicted measles mRNAs). The significance of these observations is discussed.

Aromatic metabolism in the fungi. Growth of Rhodotorula mucilaginosa in p-hydroxybenzoate-limited chemostats and the effects of growth rate on the synthesis of enzymes of the 3-oxoadipate pathway.

Rhodotorula mucilaginosa was grown in p-hydroxybenzoate-limited chemostats over the dilution rate (D) range 0.01 to 0.17 h-1 and growth was adequately described by the Monod theory when maintenance energy requirements were considered. The p-hydroxy-benzoate affinity constant, K8, had the relatively high value of 270 mg/I. The yield from p-hydroxbenzoate varied with dilution rate but was constant above D equal 0.07 h-1 at 0.56 g yeast/g substrate utilised. The maintenance coefficeint for growth on the aromatic substrate was 20 mg/g yeast/hr. Culture viability decreased linearly as the dilution rate was reduced. 4-Hydroxybenzoate 3-mono-oxygenase, protocatechuate 3,4-dioxygenases, 3-carboxymuconate cyclase and 3-carboxymuconolactone hydrolase activities were dilution rate-dependent, results which accord with the substrate in inducibility of these enzymes. Under carbon-limited growth conditions the addition of glucose, a catabolite repressor of these enzymes, to the aromatic medium stimulated their synthesis. Data were also obtained which indicated that whereas the synthesis of the cyclase and the hydrolase was coordinately controlled, that of the first two enzymes of the 3-oxodipate pathway was under independent control.