Spiro fused diterpene-indole alkaloids from a creek-bottom-derived Aspergillus terreus

Four metabolites, teraspiridoles A-D (2-5), formed from the merger of a diterpene and modified indole scaffold were obtained from an Aspergillus terreus isolate. The structures and absolute configurations of these natural products were established using NMR, mass spectrometry, Marfey's method, VCD, and ECD data. Teraspiridole B (3) exhibited weak inhibition of planaria regeneration/survival.

Performance of comorbidity indices in measuring outcomes after acute myocardial infarction in Australian indigenous and non-indigenous patients

BACKGROUND

Indigenous Australians have higher prevalence of chronic diseases and worse acute care outcomes than other Australians. The extent to which higher chronic disease comorbidity levels are responsible for their worse outcomes is not clear, and the performance of comorbidity indices has not been assessed for this population with very high comorbidity levels.

METHODS

Using hospital separations data, the Charlson and Elixhauser comorbidity indices were used to measure chronic disease prevalence in 2035 indigenous and non-indigenous patients hospitalised after their first acute myocardial infarction (AMI) in the Northern Territory of Australia between 1992 and 2004, and to adjust for comorbidity in multivariate analysis of mortality outcomes (in-hospital and long-term deaths from coronary heart disease and all causes). Index performance was assessed by the difference between C statistic, Akaike information criterion statistic and estimate of excess indigenous mortality in models with and without comorbidity adjustment.

RESULTS

Comorbidity index scores were higher for indigenous than non-indigenous patients and increased considerably over time, at least partly because of information bias. Indigenous patients' higher risk of in-hospital all-cause death was almost fully explained by their higher comorbidity levels. Their higher risk of long-term coronary heart disease and all-cause death was partially explained by higher comorbidity levels. Charlson and Elixhauser indices performed satisfactorily and similarly in this population.

CONCLUSION

Comorbidity indices performed well in a population with very high chronic disease prevalence. After adjusting for comorbidity, short-term outcomes were similar for indigenous and non-indigenous AMI patients, but comorbidity at the time of the acute episode only partly explained the worse long-term outcomes for indigenous patients.

Small-molecule suppressors of Candida albicans biofilm formation synergistically enhance the antifungal activity of amphotericin B against clinical Candida isolates

A new class of fungal biofilm inhibitors represented by shearinines D (3) and E (4) were obtained from a Penicillium sp. isolate. The inhibitory activities of 3 and 4 were characterized using a new imaging flow-cytometer technique, which enabled the rapid phenotypic analysis of Candida albicans cell types (budding yeast cells, germ tube cells, pseudohyphae, and hyphae) in biofilm populations. The results were confirmed by experimental data obtained from three-dimensional confocal laser scanning microscopy and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays. These data indicate that 3 and 4 inhibited C. albicans biofilm formation by blocking the outgrowth of hyphae at a relatively late stage of biofilm development (IC50 = 8.5 and 7.6 μM, respectively). However, 3 and 4 demonstrated comparatively weak activity at disrupting existing biofilms. Compounds 3 and 4 also exhibited synergistic activities with amphotericin B against C. albicans and other clinical Candida isolates by enhancing the potency of amphotericin B up to 8-fold against cells in both developing and established biofilms. These data suggest that the Candida biofilm disruption and amphotericin B potentiating effects of 3 and 4 could be mediated through multiple biological targets. The shearinines are good tools for testing the potential advantages of using adjunctive therapies in combination with antifungals.

Neural transdifferentiation of human bone marrow mesenchymal stem cells on hydrophobic polymer-modified surface and therapeutic effects in an animal model of ischemic stroke

Human bone marrow-derived mesenchymal stem cells (MSCs) have multi-lineage differentiation potential and can become cells of mesodermal and neural lineages. These stem cells thus hold considerable clinical promise for the treatment of neurodegenerative diseases. For successful regeneration of damaged neural tissues, directed differentiation of neural or neuronal precursor cells from MSCs and integration of transplanted cells are pivotal factors. We induced MSCs into neurogenesis using a modified protocol. The therapeutic potency of the resulting neural progenitor cells in a rat model of ischemic stroke was analyzed. Using a highly hydrophobic diphenylamino-s-triazine-bridged p-phenylene (DTOPV)-coated surface and adopting a procedure for propagation of neural stem cells, we efficiently converted MSCs into neurosphere-like cellular aggregates (NS-MSCs). The spherical cells were subsequently induced to differentiate into neural cells expressing neuroectodermal markers. To determine whether these cells had neuronal fates and induced neuro-protective effects in vivo, NS-MSCs were intra-cerebrally administered to rats 48h after permanent middle cerebral artery occlusion (pMCAo). The results showed a remarkable attenuation of ischemic damage with significant functional recovery, although the cells were not fully incorporated into the damaged tissues on post-operative day 26. Improvement in the NS-MSC-transplanted rats was faster than in the MSC group and suppression of inflammation was likely the key factor. Thus, our culture system using the hydrophobic surface of a biocompatible DTOPV coating efficiently supported neural cell differentiation from MSCs. Neural-primed MSCs exhibited stronger therapeutic effects than MSCs in rat brains with pMCAo.

Production of cytotoxic glidobactins/luminmycins by Photorhabdus asymbiotica in liquid media and live crickets

Photorhabdus asymbiotica engages in a two-part life cycle that requires adaptation to both symbiotic and pathogenic phases. The genome of P. asymbiotica contains several gene clusters, which are predicted to be involved in the biosynthesis of unique secondary metabolites that are hypothesized to enhance the bacterium's pathogenic capabilities. However, recent reports on Photorhabdus secondary metabolite production have indicated that many of its genes are silent under laboratory culture conditions. Using a circumscribed panel of media and alternative fermentation conditions, we have successfully achieved the production of a series of new and known glidobactin/luminmycin derivatives from P. asymbiotica including glidobactin A (1), luminmycin A (2), and luminmycin D (3). These compounds were also obtained upon infection of live crickets with the bacterium. Luminmycin D showed cytotoxicity against human pancreatic cells (IC50 of 0.11 μM), as well as proteasome inhibition (IC50 of 0.38 μM).

Surfactant-mediated gene transfer for animal cells

A commercially available cationic surfactant, dimethyl-dioctadecyl ammonium bromide (DDAB), was used for making lipid vesicles. DDAB easily dissolved in water at 60 °C and formed lipid vesicles at room temperature. The lipid vesicles showed very low cytotoxicity compared with other cationic surfactants. After the lipid vesicles were mixed with plasmid DNA solution, the solution was added to mammalian cells. The addition of a nonionic surfactant (Tween 80) to the cationic lipid vesicles at the weight ratio of 1:1 enhanced transfection efficiency. Adding more or less than the optimal amounts of DNA and lipid vesicles resulted in decreased transfection efficiency. With the optimal amounts of DNA (pCMVβ) and lipid vesicles, about 90-95% of CHO-K1 and BHK-21C13 cells transiently expressed β-galactosidase activity 24 h after transfection. By this procedure, stable transformants around 10(5) cells corresponding to 10% efficiency could be obtained by one batch transfection.

The mean intensity ofo activation than the number of activated voxels is a better index to reflect the levels of visuospatial performance

This study is to identify the more sensitive method to measure the brain activation by the visuospatial performance level by comparing two different methods of measuremtnt (i.e., a method calculating the number of activated voxels and the other, the mean intensity of activated voxels). Sixteen right-handed male college students (mean age 23.2 years) participated in this study and function brain images were scanned with a 3T MRI using the single-shot EPI method during visuospatial performance. There found no brain areas with correlation between the visuospatial performance level and number of activated voxels. However, there found a sifgnificant correlatgion between the visuospatial performance level and the mean intensity of selected activated voxels in the parietal, frontal, and other areas.f In conclusion, the method of meanintensity rather than the one of the number is considered as a better index.

Secondary metabolites produced by fungi derived from a microbial mat encountered in an iron-rich natural spring

A collection of fungal isolates was obtained from a complex microbial mat, which occupied an iron-rich freshwater spring that feeds into Clear Creek, Golden, Colorado, USA. Two of the fungal isolates, a Glomeromycete (possible Entrophospora sp.) and a Dothideomycete (possible Phaeosphaeria sp.), were investigated for bioactive secondary metabolites. In total, six new compounds consisting of clearanols A-E (5, 6, 10-12) and disulochrin (7) were purified and their structures were determined. Disulochrin exhibited modest antibacterial activity against methicillin-resistant Staphylococcus aureus, whereas clearanol C showed weak inhibitory activity against Candida albicans biofilm formation.

Waikialoid A suppresses hyphal morphogenesis and inhibits biofilm development in pathogenic Candida albicans

A chemically prolific strain of Aspergillus was isolated from a soil sample collected near Waikiki Beach, Honolulu, Hawaii. The fungus produced several secondary metabolites, which were purified and placed in our natural products library and were later screened for substances capable of inhibiting biofilm formation by Candida albicans. It was determined that one of the secondary metabolites from the Hawaiian fungal isolate, a new complex prenylated indole alkaloid named waikialoid A (1), inhibited biofilm formation with an IC(50) value of 1.4 μM. Another structurally unrelated, presumably polyketide metabolite, waikialide A (15), also inhibited C. albicans biofilm formation, but was much less potent (IC(50) value of 32.4 μM). Microscopy studies revealed that compound 1 also inhibited C. albicans hyphal morphogenesis. While metabolite 1 appears ineffective at disrupting preformed biofilms, the accumulated data indicate that the new compound may exert its activity against C. albicans during the early stages of surface colonization involving cell adherence, hyphal development, and/or biofilm assembly. Unlike some other stephacidin/notoamide compounds, metabolite 1 was not cytotoxic to fungi or human cells (up to 200 μM), which makes this an intriguing model compound for studying the adjunctive use of biofilm inhibitors in combination with standard antifungal antibiotics.

Fungal biofilm inhibitors from a human oral microbiome-derived bacterium

The human mouth is home to a rich assortment of native and transient microorganisms. One of the commonly encountered bacterial species, Streptococcus mutans, was shown to generate the novel hybrid polyketide-nonribosomal peptide metabolite mutanobactin A (1). We have characterized three new analogues, mutanobactins B-D (2-4), and subjected these compounds to further biomedical evaluation. Metabolites 1, 2, and 4 were found to inhibit biofilm formation by the fungal oral-pathogen Candida albicans. Compound 4 was the most potent metabolite with an IC(50) value of 5.3 ± 0.9 μM. Using a combination of Marfey's analysis, proton spin-spin coupling, and (1)H-(1)H NOESY data, we proposed absolute configuration assignments in toto for 1-3 and a partial assignment for 4. In addition, feeding studies with isotopically labeled precursor metabolites (acetate and amino acids) have helped to determine the biosynthetic origins of this unique natural product family.

P2-08-12: Additional Lesion Found in Preoperative Breast MRI; Is Routine Use Justified?

Preoperative breast MRI has been increasingly performed in patients with newly diagnosed breast cancer due to its high sensitivity in assessing the extent and additional malignant foci. But due to it's low specificity, role of routine preoperative breast MRI has become an issue. In this study we aught to analyze the characteristics of the additional lesion found in preoperative breast MRI and to evaluate the clinicopathological factors in association with likelihood of having additional malignancy.

We retrospectively reviewed 2491 patients who undergone surgery due to breast cancer in Seoul National University Hospital(SNUH) between Jan 2006 and Dec 2010. Neoadjuvant chemotherapy cases, patients undergone initial sonography in other center or ones with prior excision were excluded and total 1068 patients were analyzed. The additional lesion was defined as the lesion not found in initial sonography and detected in preoperative breast MRI. The pathology of the additional lesion was reviewed and the association between the clinicopathologic factors and additional malignancy were evaluated. Accuracy of breast MRI was estimated regarding cancer yield, positive predictive value(PPV).

Mean age at diagnosis was 50.9 years (21 to 85 years). Overall detection rate of additional lesion was 26.2%(280 out of 1068). Mean size of the additional lesion was 9.8mm(3-51). Additional lesions consist of 99(35.4% of 280) C4 or higher, 174(62.1% of 280) below C4, 7(2.5% of 280) C0 lesions. Among them 100 patients undergone onstage surgery. 5(55% of 100) lesions were in ipsilateral breast and 45(45% of 100) in contralateral breast. Breast conserving surgery and mastectomy rate of the 100 onstage-operation group was 36% versus 64% and 64.6% versus 35.4% in total 1068 patients, showing no significant change of operation method of the primary cancer owing to additional lesion.

Among the 100 patients, 54(19.3% of 280) were benign, 3(1.1% of 280) were atypical ductal hyperplasia, 13(4.6% of 280) were in situ carcinoma, 19(6.8% of 280) were invasive carcinoma and 11(3.9% of 280) were unknown. Cancer yield was 2.99%(32 out of 1068) and PPV of preoperative breast MRI was 39.0%(31 out of 82).

In univariate analysis, young age and premenopausal patients showed to have higher rate of additional cancer found in MRI(p=0.022, p=0.036). Breast density, size and LN status of the primary cancer didn't show significancy and neither the hormone receptor status with each p value 0.705, 0.381, 0.973, 0.375 respectively. Lobular carcinoma(ILC or mixed IDC with ILC) and low grade carcinoma showed significancy of having additional malignancy (p=0.019, 0.022). In multivariate analysis age, low grade carcinoma and lobular carcinoma showed independent association with p value 0.014, 0.039, 0.035 respectively(HR 0.95, 95%CI:0.94 o 0.99),(HR 0.39, 95%CI:0.16 to 0.96),(HR 5.66, 95%CI:1.13 to 28.39).

Routine preoperative breast MRI use can result in overtreatment also with delay in surgical management. In our data, younger age, low grade carcinoma, lobular carcinoma showed independent association having additional malignant foci in breast MRI. With the basis of mammography and sonography, preoperative breast MRI should only be done when additional gain is considered to overcome the flaws.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-12.