415 research outputs found
Multifactorial Induction of an Orphan PKS-NRPS Gene Cluster in Aspergillus terreus
SummaryMining the genome of the pathogenic fungus Aspergillus terreus revealed the presence of an orphan polyketide-nonribosomal-peptide synthetase (PKS-NRPS) gene cluster. Induced expression of the transcriptional activator gene adjacent to the PKS-NRPS gene was not sufficient for the activation of the silent pathway. Monitoring gene expression, metabolic profiling, and using a lacZ reporter strain allowed for the systematic investigation of physiological conditions that eventually led to the discovery of isoflavipucine and dihydroisoflavipucine. Phytotoxin formation is only activated in the presence of certain amino acids, stimulated at alkaline pH, but strictly repressed in the presence of glucose. Global carbon catabolite repression by CreA cannot be abolished by positive-acting factors such as PacC and overrides the pathway activator. Gene inactivation and stable isotope labeling experiments unveiled the molecular basis for flavipucine/fruit rot toxin biosynthesis
4-Amino-8-cyclopentyloxy-7-methoxy-2H-chromen-2-one monohydrate
The asymmetric unit of the title compound, C15H17NO4·H2O, contains two organic molecules with marginal differences between them and two water molecules. The chromine rings in both molecules are essentially planar, with maximum deviations of 0.012 (2) and 0.060 (2) Å. The five-membered cyclopentane rings adopt envelope conformations in both molecules. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, resulting in a three-dimensional network
Treatment Effect of CT-Guided Periradicular Injections in Context of Different Contrast Agent Distribution Patterns
Acutely manifesting radicular pain syndromes associated with degenerations of the lower
spine are frequent ailments with a high rate of recurrence. Part of the conservative management are
periradicular infiltrations of analgesics and steroids. The purpose of this study is to evaluate the
dependence of the clinical efficacy of CT-guided periradicular injections on the pattern of contrast
distribution and to identify the best distribution pattern that is associated with the most effective pain
relief. Using a prospective study design, 161 patients were included in this study, ensuring ethical
standards. Statistical analysis was performed, with the level of statistical significance set at p = 0.05.
A total of 37.9% of patients experienced significant but not long-lasting (four weeks on average)
complete pain relief. A total of 44.1% of patients experienced prolonged, subjectively satisfying pain
relief of more than four weeks to three months. A total of 18% of patients had complete and sustained
relief for more than six months. A significant correlation exists between circumferential, large area
contrast distribution including the zone of action between the disc and affected nerve root contrast
distribution pattern with excellent pain relief. Our results support the value of CT-guided contrast
injection for achieving a good efficacy, and, if necessary, indicative repositioning of the needle to
ensure a circumferential distribution pattern of corticosteroids for the sufficient treatment of radicular
pain in degenerative spine disease
Assessment of a Reliable Fractional Anisotropy Cutoff in Tractography of the Corticospinal Tract for Neurosurgical Patients
Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p < 0.0001). Postoperatively, the FA values were more condensed around their mean (p < 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs
Antibiotic-producing symbionts dynamically transition between plant pathogenicity and insect-defensive mutualism
Pathogenic and mutualistic bacteria associated with eukaryotic hosts often lack distinctive genomic features, suggesting regular transitions between these lifestyles. Here we present evidence supporting a dynamic transition from plant pathogenicity to insect-defensive mutualism in symbiotic Burkholderia gladioli bacteria. In a group of herbivorous beetles, these symbionts protect the vulnerable egg stage against detrimental microbes. The production of a blend of antibiotics by B. gladioli, including toxoflavin, caryoynencin and two new antimicrobial compounds, the macrolide lagriene and the isothiocyanate sinapigladioside, likely mediate this defensive role. In addition to vertical transmission, these insect symbionts can be exchanged via the host plant and retain the ability to initiate systemic plant infection at the expense of the plant’s fitness. Our findings provide a paradigm for the transition between pathogenic and mutualistic lifestyles and shed light on the evolution and chemical ecology of this defensive mutualism
Histogram Analysis of Diffusion Weighted Imaging in Low-Grade Gliomas: in vivo Characterization of Tumor Architecture and Corresponding Neuropathology
Background: Low-grade gliomas (LGG) in adults are usually slow growing and frequently
asymptomatic brain tumors, originating from glial cells of the central nervous system
(CNS). Although regarded formally as “benign” neoplasms, they harbor the potential of
malignant transformation associated with high morbidity and mortality. Their complex
and unpredictable tumor biology requires a reliable and conclusive presurgical magnetic
resonance imaging (MRI). A promising and emerging MRI approach in this context is
histogram based apparent diffusion coefficient (ADC) profiling, which recently proofed
to be capable of providing prognostic relevant information in different tumor entities.
Therefore, our study investigated whether histogram profiling of ADC distinguishes grade
I from grade II glioma, reflects the proliferation index Ki-67, as well as the IDH (isocitrate
dehydrogenase) mutation and MGMT (methylguanine-DNA methyl-transferase) promotor
methylation status.
Material and Methods: Pre-treatment ADC volumes of 26 LGG patients were used for
histogram-profiling. WHO-grade, Ki-67 expression, IDH mutation, and MGMT promotor
methylation status were evaluated. Comparative and correlative statistics investigating
the association between histogram-profiling and neuropathology were performed.
Results: Almost the entire ADC profile (p25, p75, p90, mean, median) was significantly
lower in grade II vs. grade I gliomas. Entropy, as second order histogram parameter
of ADC volumes, was significantly higher in grade II gliomas compared with grade I
gliomas. Mean, maximum value (ADCmax) and the percentiles p10, p75, and p90 of ADC
histogram were significantly correlated with Ki-67 expression. Furthermore, minimum
ADC value (ADCmin) was significantly associated with MGMT promotor methylation
status as well as ADC entropy with IDH-1 mutation status.
Conclusions: ADC histogram-profiling is a valuable radiomic approach, which helps
differentiating tumor grade, estimating growth kinetics and probably prognostic relevant
genetic as well as epigenetic alterations in LGG
Single-Center Experience With the Bare p48MW Low-Profile Flow Diverter and Its Hydrophilically Covered Version for Treatment of Bifurcation Aneurysms in Distal Segments of the Anterior and Posterior Circulation
Background and Purpose: Flow diversion has profoundly changed the way aneurysms
are treated. However, it conventionally requires dual antiplatelet medication and has yet
been considered off-label use in the posterior circulation or within peripheral vessels of the
anterior circulation. Here, we report our experience with the p48MW/p48MW hydrophilic
coating (HPC) in the anterior and posterior circulation. This novel low-profile flow diverter
is specifically designed for treatment of small peripheral vessels, and the p48MW HPC
has an anti-thrombotic polymer coating, which allows application of a single antiplatelet
function medication in conditions that expectably require further surgery.
Materials and Methods: Thirty-two patients were prospectively included. Twenty-six
treatments were performed with one flow diverter, four required two overlapping flow
diverters, one case demanded three overlapping flow diverters, and in one case,
extensive dissecting aneurysm telescoping with eight flow diverters was necessary.
Twenty-two complex bifurcation aneurysms were treated. Three months’ follow-up was
available for 14 patients.
Results: Deployment was uneventful in all cases. In four cases, undersizing was
unavoidable and resulted in significant shortening of the flow diverter, which demanded
implantation of further flow diverters to sufficiently treat the target aneurysm. Three
flow diverters required balloon angioplasty for optimal wall approximation. All parent
vessels remained patent. Available 3-month follow-up studies showed decreased influx
or delayed washout in all aneurysms; none was occluded completely. There were no
device-related clinical complications.
Conclusions: Implantation of the p48MW/p48MW HPC is safe and effective for
treatment of distally located cerebral aneurysms. Considering the reported rates of
ischemic complications associated with flow diversion of complex bifurcation aneurysms,
the p48MW/p48MW HPC potentially provides increased safety for complex bifurcation
aneurysms in the anterior and posterior circulation
Endovascular Treatment of Intracranial Aneurysms in Small Peripheral Vessel Segments—Efficacy and Intermediate Follow-Up Results of Flow Diversion With the Silk Vista Baby Low-Profile Flow Diverter
Background and Purpose: Low-profile flow diverter stents (FDS) quite recently
amended peripheral segments as targets for hemodynamic aneurysm treatment;
however, reports on outcomes, especially later than 3 months, are scarce. This study
therefore reports our experience with the novel silk vista baby (SVB) FDS and respective
outcomes after 8 and 11 months with special respect to specific adverse events.
Materials and Methods: Forty-four patients (mean age, 53 years) harboring 47
aneurysms treated with the SVB between June 2018 and December 2019 were included
in our study. Clinical, procedural, and angiographic data were collected. Follow-ups were
performed on average after 3, 8, and 11 months, respectively. Treatment effect was
assessed using the O’Kelly Marotta (OKM) grading system.
Results: Overall, angiographic follow-ups were available for 41 patients/45 aneurysms.
Occlusion or significant reduction in aneurysmal perfusion (OKM: D1, B1–B3 and
A2–A3) was observed in 98% of all aneurysms after 8 months. Only 2% of the treated
aneurysms remained morphologically unaltered and without an apparent change in
perfusion (OKM A1). Adverse events in the early post-interventional course occurred
in seven patients; out of them, mRS-relevant morbidity at 90 days related to FDS
treatment was observable in two patients. One death occurred in the context of
severe SAH related to an acutely ruptured dissecting aneurysm of the vertebral artery.
Conclusion: The SVB achieves sufficient occlusion rates of intracranial aneurysms
originating from peripheral segments, which are comparable to prior established
conventional FDS with acceptably low complication rates. However, alteration of a
hemodynamic equilibrium in distal localizations requires special attention to prevent
ischemic events
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