[Specialized Concepts for the Management of Severe Neurotrauma]. / Spezielle Behandlungskonzepte bei schwerem Neurotrauma.

Neurotrauma results from violence on structures of the central or peripheral nervous system and is a clinically common disease entity with high relevance for patients' long-term outcome. The application of evidence-based diagnostic and therapeutic concepts aims to minimize secondary injury and thus to improve treatment outcome. This article describes the current management of the two main injury patterns of neurotrauma - traumatic brain and spinal cord injury.

Anesthesia triggers drug delivery to experimental glioma in mice by hijacking caveolar transport.

BACKGROUND: Pharmaceutical intervention in the CNS is hampered by the shielding function of the blood-brain barrier (BBB). To induce clinical anesthesia, general anesthetics such as isoflurane readily penetrate the BBB. Here, we investigated whether isoflurane can be utilized for therapeutic drug delivery. METHODS: Barrier function in primary endothelial cells was evaluated by transepithelial/transendothelial electrical resistance, and nanoscale STED and SRRF microscopy. In mice, BBB permeability was quantified by extravasation of several fluorescent tracers. Mouse models including the GL261 glioma model were evaluated by MRI, immunohistochemistry, electron microscopy, western blot, and expression analysis. RESULTS: Isoflurane enhances BBB permeability in a time- and concentration-dependent manner. We demonstrate that, mechanistically, isoflurane disturbs the organization of membrane lipid nanodomains and triggers caveolar transport in brain endothelial cells. BBB tightness re-establishes directly after termination of anesthesia, providing a defined window for drug delivery. In a therapeutic glioblastoma trial in mice, simultaneous exposure to isoflurane and cytotoxic agent improves efficacy of chemotherapy. CONCLUSIONS: Combination therapy, involving isoflurane-mediated BBB permeation with drug administration has far-reaching therapeutic implications for CNS malignancies.

Association of Surgical Hematoma Evacuation vs Conservative Treatment With Functional Outcome in Patients With Cerebellar Intracerebral Hemorrhage.

Importance: The association of surgical hematoma evacuation with clinical outcomes in patients with cerebellar intracerebral hemorrhage (ICH) has not been established. Objective: To determine the association of surgical hematoma evacuation with clinical outcomes in cerebellar ICH. Design, Setting, and Participants: Individual participant data (IPD) meta-analysis of 4 observational ICH studies incorporating 6580 patients treated at 64 hospitals across the United States and Germany (2006-2015). Exposure: Surgical hematoma evacuation vs conservative treatment. Main Outcomes and Measures: The primary outcome was functional disability evaluated by the modified Rankin Scale ([mRS] score range: 0, no functional deficit to 6, death) at 3 months; favorable (mRS, 0-3) vs unfavorable (mRS, 4-6). Secondary outcomes included survival at 3 months and at 12 months. Analyses included propensity score matching and covariate adjustment, and predicted probabilities were used to identify treatment-related cutoff values for cerebellar ICH. Results: Among 578 patients with cerebellar ICH, propensity score-matched groups included 152 patients with surgical hematoma evacuation vs 152 patients with conservative treatment (age, 68.9 vs 69.2 years; men, 55.9% vs 51.3%; prior anticoagulation, 60.5% vs 63.8%; and median ICH volume, 20.5 cm3 vs 18.8 cm3). After adjustment, surgical hematoma evacuation vs conservative treatment was not significantly associated with likelihood of better functional disability at 3 months (30.9% vs 35.5%; adjusted odds ratio [AOR], 0.94 [95% CI, 0.81 to 1.09], P = .43; adjusted risk difference [ARD], -3.7% [95% CI, -8.7% to 1.2%]) but was significantly associated with greater probability of survival at 3 months (78.3% vs 61.2%; AOR, 1.25 [95% CI, 1.07 to 1.45], P = .005; ARD, 18.5% [95% CI, 13.8% to 23.2%]) and at 12 months (71.7% vs 57.2%; AOR, 1.21 [95% CI, 1.03 to 1.42], P = .02; ARD, 17.0% [95% CI, 11.5% to 22.6%]). A volume range of 12 to 15 cm3 was identified; below this level, surgical hematoma evacuation was associated with lower likelihood of favorable functional outcome (volume ≤12 cm3, 30.6% vs 62.3% [P = .003]; ARD, -34.7% [-38.8% to -30.6%]; P value for interaction, .01), and above, it was associated with greater likelihood of survival (volume ≥15 cm3, 74.5% vs 45.1% [P < .001]; ARD, 28.2% [95% CI, 24.6% to 31.8%]; P value for interaction, .02). Conclusions and Relevance: Among patients with cerebellar ICH, surgical hematoma evacuation, compared with conservative treatment, was not associated with improved functional outcome. Given the null primary outcome, investigation is necessary to establish whether there are differing associations based on hematoma volume.

Characteristics in Non-Vitamin K Antagonist Oral Anticoagulant-Related Intracerebral Hemorrhage.

Background and Purpose- Given inconclusive studies, it is debated whether clinical and imaging characteristics, as well as functional outcome, differ among patients with intracerebral hemorrhage (ICH) related to vitamin K antagonists (VKA) versus non-vitamin K antagonist (NOAC)-related ICH. Notably, clinical characteristics according to different NOAC agents and dosages are not established. Methods- Multicenter observational cohort study integrating individual patient data of 1328 patients with oral anticoagulation-associated ICH, including 190 NOAC-related ICH patients, recruited from 2011 to 2015 at 19 tertiary centers across Germany. Imaging, clinical characteristics, and 3-months modified Rankin Scale (mRS) outcomes were compared in NOAC- versus VKA-related ICH patients. Propensity score matching was conducted to adjust for clinically relevant differences in baseline parameters. Subgroup analyses were performed regarding NOAC agent, dosing and present clinically relevant anticoagulatory activity (last intake <12h/24h or NOAC level >30 ng/mL). Results- Despite older age in NOAC patients, there were no relevant differences in clinical and hematoma characteristics between NOAC- and VKA-related ICH regarding baseline hematoma volume (median [interquartile range]: NOAC, 14.7 [5.1-42.3] mL versus VKA, 16.4 [5.8-40.6] mL; P=0.33), rate of hematoma expansion (NOAC, 49/146 [33.6%] versus VKA, 235/688 [34.2%]; P=0.89), and the proportion of patients with unfavorable outcome at 3 months (mRS, 4-6: NOAC 126/179 [70.4%] versus VKA 473/682 [69.4%]; P=0.79). Subgroup analyses revealed that NOAC patients with clinically relevant anticoagulatory effect had higher rates of intraventricular hemorrhage (n/N [%]: present 52/109 [47.7%] versus absent 9/35 [25.7%]; P=0.022) and hematoma expansion (present 35/90 [38.9%] versus absent 5/30 [16.7%]; P=0.040), whereas type of NOAC agent or different NOAC-dosing regimens did not result in relevant differences in imaging characteristics or outcome. Conclusions- If effectively anticoagulated, there are no differences in hematoma characteristics and functional outcome among patients with NOAC- or VKA-related ICH. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT03093233.

Heparin for prophylaxis of venous thromboembolism in intracerebral haemorrhage.

OBJECTIVE: To determine the occurrence of intracranial haemorrhagic complications (IHC) on heparin prophylaxis (low-dose subcutaneous heparin, LDSH) in primary spontaneous intracerebral haemorrhage (ICH) (not oral anticoagulation-associated ICH, non-OAC-ICH), vitamin K antagonist (VKA)-associated ICH and non-vitamin K antagonist oral anticoagulant (NOAC)-associated ICH. METHODS: Retrospective cohort study (RETRACE) of 22 participating centres and prospective single-centre study with 1702 patients with VKA-associated or NOAC-associated ICH and 1022 patients with non-OAC-ICH with heparin prophylaxis between 2006 and 2015. Outcomes were defined as rates of IHC during hospital stay among patients with non-OAC-ICH, VKA-ICH and NOAC-ICH, mortality and functional outcome at 3 months between patients with ICH with and without IHC. RESULTS: IHC occurred in 1.7% (42/2416) of patients with ICH. There were no differences in crude incidence rates among patients with VKA-ICH, NOAC-ICH and non-OAC-ICH (log-rank p=0.645; VKA-ICH: 27/1406 (1.9%), NOAC-ICH 1/130 (0.8%), non-OAC-ICH 14/880 (1.6%); p=0.577). Detailed analysis according to treatment exposure (days with and without LDSH) revealed no differences in incidence rates of IHC per 1000 patient-days (LDSH: 1.43 (1.04-1.93) vs non-LDSH: 1.32 (0.33-3.58), conditional maximum likelihood incidence rate ratio: 1.09 (0.38-4.43); p=0.953). Secondary outcomes showed differences in functional outcome (modified Rankin Scale=4-6: IHC: 29/37 (78.4%) vs non-IHC: 1213/2048 (59.2%); p=0.019) and mortality (IHC: 14/37 (37.8%) vs non-IHC: 485/2048 (23.7%); p=0.045) in disfavour of patients with IHC. Small ICH volume (OR: volume <4.4 mL: 0.18 (0.04-0.78); p=0.022) and low National Institutes of Health Stroke Scale (NIHSS) score on admission (OR: NIHSS <4: 0.29 (0.11-0.78); p=0.014) were significantly associated with fewer IHC. CONCLUSIONS: Heparin administration for venous thromboembolism (VTE) prophylaxis in patients with ICH appears to be safe regarding IHC among non-OAC-ICH, VKA-ICH and NOAC-ICH in this observational cohort analysis. Randomised controlled trials are needed to verify the safety and efficacy of heparin compared with other methods for VTE prevention.

Management of therapeutic anticoagulation in patients with intracerebral haemorrhage and mechanical heart valves.

Aims: Evidence is lacking regarding acute anticoagulation management in patients after intracerebral haemorrhage (ICH) with implanted mechanical heart valves (MHVs). Our objective was to investigate anticoagulation reversal and resumption strategies by evaluating incidences of haemorrhagic and thromboembolic complications, thereby defining an optimal time-window when to restart therapeutic anticoagulation (TA) in patients with MHV and ICH. Methods and results: We pooled individual patient-data (n = 2504) from a nationwide multicentre cohort-study (RETRACE, conducted at 22 German centres) and eventually identified MHV-patients (n = 137) with anticoagulation-associated ICH for outcome analyses. The primary outcome consisted of major haemorrhagic complications analysed during hospital stay according to treatment exposure (restarted TA vs. no-TA). Secondary outcomes comprised thromboembolic complications, the composite outcome (haemorrhagic and thromboembolic complications), timing of TA, and mortality. Adjusted analyses involved propensity-score matching and multivariable cox-regressions to identify optimal timing of TA. In 66/137 (48%) of patients TA was restarted, being associated with increased haemorrhagic (TA = 17/66 (26%) vs. no-TA = 4/71 (6%); P < 0.01) and a trend to decreased thromboembolic complications (TA = 1/66 (2%) vs. no-TA = 7/71 (10%); P = 0.06). Controlling treatment crossovers provided an incidence rate-ratio [hazard ratio (HR) 10.31, 95% confidence interval (CI) 3.67-35.70; P < 0.01] in disadvantage of TA for haemorrhagic complications. Analyses of TA-timing displayed significant harm until Day 13 after ICH (HR 7.06, 95% CI 2.33-21.37; P < 0.01). The hazard for the composite-balancing both complications, was increased for restarted TA until Day 6 (HR 2.51, 95% CI 1.10-5.70; P = 0.03). Conclusion: Restarting TA within less than 2 weeks after ICH in patients with MHV was associated with increased haemorrhagic complications. Optimal weighing-between least risks for thromboembolic and haemorrhagic complications-provided an earliest starting point of TA at Day 6, reserved only for patients at high thromboembolic risk.

Lead optimization toward proof-of-concept tools for Huntington's disease within a 4-(1H-pyrazol-4-yl)pyrimidine class of pan-JNK inhibitors.

Through medicinal chemistry lead optimization studies focused on calculated properties and guided by X-ray crystallography and computational modeling, potent pan-JNK inhibitors were identified that showed submicromolar activity in a cellular assay. Using in vitro ADME profiling data, 9t was identified as possessing favorable permeability and a low potential for efflux, but it was rapidly cleared in liver microsomal incubations. In a mouse pharmacokinetics study, compound 9t was brain-penetrant after oral dosing, but exposure was limited by high plasma clearance. Brain exposure at a level expected to support modulation of a pharmacodynamic marker in mouse was achieved when the compound was coadministered with the pan-cytochrome P450 inhibitor 1-aminobenzotriazole.

Anticoagulant reversal, blood pressure levels, and anticoagulant resumption in patients with anticoagulation-related intracerebral hemorrhage.

IMPORTANCE: Although use of oral anticoagulants (OACs) is increasing, there is a substantial lack of data on how to treat OAC-associated intracerebral hemorrhage (ICH). OBJECTIVE: To assess the association of anticoagulation reversal and blood pressure (BP) with hematoma enlargement and the effects of OAC resumption. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study at 19 German tertiary care centers (2006-2012) including 1176 individuals for analysis of long-term functional outcome, 853 for analysis of hematoma enlargement, and 719 for analysis of OAC resumption. EXPOSURES: Reversal of anticoagulation during acute phase, systolic BP at 4 hours, and reinitiation of OAC for long-term treatment. MAIN OUTCOMES AND MEASURES: Frequency of hematoma enlargement in relation to international normalized ratio (INR) and BP. Incidence analysis of ischemic and hemorrhagic events with or without OAC resumption. Factors associated with favorable (modified Rankin Scale score, 0-3) vs unfavorable functional outcome. RESULTS: Hemorrhage enlargement occurred in 307 of 853 patients (36.0%). Reduced rates of hematoma enlargement were associated with reversal of INR levels <1.3 within 4 hours after admission (43/217 [19.8%]) vs INR of ≥1.3 (264/636 [41.5%]; P < .001) and systolic BP <160 mm Hg at 4 hours (167/504 [33.1%]) vs ≥160 mm Hg (98/187 [52.4%]; P < .001). The combination of INR reversal <1.3 within 4 hours and systolic BP of <160 mm Hg at 4 hours was associated with lower rates of hematoma enlargement (35/193 [18.1%] vs 220/498 [44.2%] not achieving these values; OR, 0.28; 95% CI, 0.19-0.42; P < .001) and lower rates of in-hospital mortality (26/193 [13.5%] vs 103/498 [20.7%]; OR, 0.60; 95% CI, 0.37-0.95; P = .03). OAC was resumed in 172 of 719 survivors (23.9%). OAC resumption showed fewer ischemic complications (OAC: 9/172 [5.2%] vs no OAC: 82/547 [15.0%]; P < .001) and not significantly different hemorrhagic complications (OAC: 14/172 [8.1%] vs no OAC: 36/547 [6.6%]; P = .48). Propensity-matched survival analysis in patients with atrial fibrillation who restarted OAC showed a decreased HR of 0.258 (95% CI, 0.125-0.534; P < .001) for long-term mortality. Functional long-term outcome was unfavorable in 786 of 1083 patients (72.6%). CONCLUSIONS AND RELEVANCE: Among patients with OAC-associated ICH, reversal of INR <1.3 within 4 hours and systolic BP <160 mm Hg at 4 hours were associated with lower rates of hematoma enlargement, and resumption of OAC therapy was associated with lower risk of ischemic events. These findings require replication and assessment in prospective studies. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01829581.

The Power of Hybrid/Fusion Imaging Metrics in Future PACS Systems: A Case Study into the White Matter Hyperintensity Prenumbra using FLAIR and Diffusion MR.

Most white matter related neurological disease exhibit a large number of White Matter Hyperintensities (WMHs) on FLAIR MRI images. However, these lesions are not well understood. At the same time, Diffusion MRI has been gaining popularity as a powerful method of characterizing White Matter (WM) integrity. This work aims to study the behavior of the diffusion signal within the WMH voxels. The goal is to develop hybrid MR metrics that leverage information from multiple MR acquisitions to solve clinical problems. In our case, we are trying to address the WMH penumbra (as defined by Maillard et al 20112) where WMH delineates a foci that is more widespread than than the actual damage area presumably due to acute inflammation. Our results show that diffusion MR metrics may be able to better delineate tissue that is inflamed versus scar tissue but may be less specific to lesions than FLAIR. Therefore, a hybrid metric that encodes information from both FLAIR and Diffusion MR may yield new and novel imaging information about the progression of white matter disease progression. We hope that this work also demonstrates how future PACS systems could have image fusion capabilities that would be able to leverage information from multiple imaging series to yield new and novel imaging contrast.

In vitro biosynthesis, isolation, and identification of predominant metabolites of 2-(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)-5,7-dimethoxyquinazolin-4(3H)-one (RVX-208).

The structures of the two predominant metabolites (M4 and M5) of RVX-208, observed both in in vitro human and animal liver microsomal incubations, as well as in plasma from animal in vivo studies, were determined. A panel of biocatalytic systems was tested to identify biocatalysts suitable for milligram scale production of metabolite M4 from RVX-208. Rabbit liver S9 fraction was selected as the most suitable system, primarily based on pragmatic metrics such as catalyst cost and estimated yield of M4 (∼55%). Glucuronidation of RVX-208 catalyzed by rabbit liver S9 fraction was optimized to produce M4 in amounts sufficient for structural characterization. Structural studies using LC/MS/MS analysis and (1)H NMR spectroscopy showed the formation of a glycosidic bond between the primary hydroxyl group of RVX-208 and glucuronic acid. NMR results suggested that the glycosidic bond has the ß-anomeric configuration. A synthetic sample of M4 confirmed the proposed structure. Metabolite M5, hypothesized to be the carboxylate of RVX-208, was prepared using human liver microsomes, purified by HPLC, and characterized by LC/MS/MS and (1)H NMR. The structure was confirmed by comparison to a synthetic sample. Both samples confirmed M5 as a product of oxidation of primary hydroxyl group of RVX-208 to carboxylic acid.

Use of in situ solid-phase adsorption in microbial natural product fermentation development.

It has been half a century since investigators first began experimenting with adding ion exchange resins during the fermentation of microbial natural products. With the development of nonionic polymeric adsorbents in the 1970s, the application of in situ product adsorption in bioprocessing has grown slowly, but steadily. To date, in situ product adsorption strategies have been used in biotransformations, plant cell culture, the production of biofuels, and selected bulk chemicals, such as butanol and lactic acid, as well as in more traditional natural product fermentation within the pharmaceutical industry. Apart from the operational gains in efficiency from the integration of fermentation and primary recovery, the addition of adsorbents during fermentation has repeatedly demonstrated the capacity to significantly increase titers by sequestering the product and preventing or mitigating degradation, feedback inhibition and/or cytotoxic effects. Adoption of in situ product adsorption has been particularly valuable in the early stages of natural product-based drug discovery programs, where quickly and cost-effectively generating multigram quantities of a lead compound can be challenging when using a wild-type strain and fermentation conditions that have not been optimized. While much of the literature involving in situ adsorption describes its application early in the drug development process, this does not imply that the potential for scale-up is limited. To date, commercial-scale processes utilizing in situ product adsorption have reached batch sizes of at least 30,000 l. Here we present examples where in situ product adsorption has been used to improve product titers or alter the ratios among biosynthetically related natural products, examine some of the relevant variables to consider, and discuss the mechanisms by which in situ adsorption may impact the biosynthesis of microbial natural products.

Early out-of-hospital non-invasive ventilation is superior to standard medical treatment in patients with acute respiratory failure: a pilot study.

OBJECTIVE: To assess in patients with acute respiratory failure (ARF) whether out-of-hospital (OOH) non-invasive ventilation (NIV) is feasible, safe and more effective compared with standard medical therapy (SMT). PATIENTS AND INTERVENTIONS: Patients with OOH ARF were randomly assigned to receive either SMT or NIV. MEASUREMENTS AND RESULTS: Fifty-one patients were enrolled, 26 of whom were randomly assigned to SMT and 25 of whom received NIV. Two patients were excluded because of protocol violations. OOH NIV was safe and effective in all patients. In the SMT group, treatment was not effective in five of 25 patients who required OOH mechanical ventilation (p=0.05). Patients in the SMT group were admitted to an intensive care unit (ICU) more frequently (n=17) (p<0.05) and for longer periods (3.7±6.4 days) (p=0.03) compared with patients in the NIV group (n=9, 1.3±2.6 days). Six patients in the SMT group required subsequent inhospital intubation and invasive ventilation during their hospital stays; only one patient in the NIV group required intubation (p=0.10). In contrast, patients in the NIV group received NIV more frequently (n=14) in hospital compared with patients in the SMT group (n=5) (p<0.01). CONCLUSIONS: OOH NIV proved to be feasible, safe and more effective for the treatment of ARF compared with SMT. OOH NIV promotes inhospital treatment with NIV and may reduce the frequency and length of ICU stays. Because the risks of OOH emergency intubation can be avoided, NIV should be the first-line treatment in OOH ARF if no contraindications are present.

The anticancer plant triterpenoid, avicin D, regulates glucocorticoid receptor signaling: implications for cellular metabolism.

Avicins, a family of apoptotic triterpene electrophiles, are known to regulate cellular metabolism and energy homeostasis, by targeting the mitochondria. Having evolved from "ancient hopanoids," avicins bear a structural resemblance with glucocorticoids (GCs), which are the endogenous regulators of metabolism and energy balance. These structural and functional similarities prompted us to compare the mode of action of avicin D with dexamethasone (Dex), a prototypical GC. Using cold competition assay, we show that Avicin D competes with Dex for binding to the GC receptor (GR), leading to its nuclear translocation. In contrast to Dex, avicin-induced nuclear translocation of GR does not result in transcriptional activation of GC-dependent genes. Instead we observe a decrease in the expression of GC-dependent metabolic proteins such as PEPCK and FASN. However, like Dex, avicin D treatment does induce a transrepressive effect on the pro-inflammatory transcription factor NF-κB. While avicin's ability to inhibit NF-κB and its downstream targets appear to be GR-dependent, its pro-apoptotic effects were independent of GR expression. Using various deletion mutants of GR, we demonstrate the requirement of both the DNA and ligand binding domains of GR in mediating avicin D's transrepressive effects. Modeling of avicin-GR interaction revealed that avicin molecule binds only to the antagonist confirmation of GR. These findings suggest that avicin D has properties of being a selective GR modulator that separates transactivation from transrepression. Since the gene-activating properties of GR are mainly linked to its metabolic effects, and the negative interference with the activity of transcription factors to its anti-inflammatory and immune suppressive effects, the identification of such a dissociated GR ligand could have great potential for therapeutic use.

Clinical outcome and imaging follow-up in acute stroke patients with normal perfusion CT and normal CT angiography.

INTRODUCTION: Acute stroke multimodal CT imaging (MMCT: non-enhanced CT, CT angiography, and CT perfusion (CTP)) may show normal results despite persistent clinical stroke. We prospectively evaluated the sensitivity/specificity of MMCT infarct detection and the clinical outcome in patients with normal MMCT findings. METHODS: From April 2007 to April 2008, all patients with acute hemispheric stroke within 6 h of symptom onset who underwent complete MMCT and MRI follow-up imaging were included. MMCT analysis included occlusion type, early infarct hypodensities (EIH), mean transit time (MTT), and cerebral blood volume (CBV) maps according to Alberta Stroke Program Early CT Score (ASPECTS). Clinical assessment included symptom onset to CT scan (≤3 h/>3 h), the National Institute of Health Stroke Scale score (admission/discharge), and the modified Rankin scale (mRS) 90 days after stroke onset. RESULTS: One hundred seven were included (mean age, 68.4 years; ≤3 h, n = 84; >3 h, n = 23; intravenous thrombolysis (IVT), n = 51; ≤3 h, n = 40; >3 h, n = 11). In patients with normal MMCT on admission (n = 54), follow-up MRT detected brain infarctions in 23 patients (lacunar strokes, n = 16; infratentorial strokes, n = 4; territorial infarction, n = 3). Sensitivity/specificity/positive predictive value/negative predictive value of any infarct detection was 69.5%/99.8%/99.9%/57.2% and of a any territorial infarct detection was 93.9%/99.9%/99.9%/93.6%, respectively. In univariate regression analysis (time to CT scan, ≤3 h/>3 h; IVT: yes/no; ASPECTS EIH/CBV/MTT, 10/<10), only the evidence of normal CTP (ASPECTS MTT = 10) had a statistically significant impact (p = 0.02) on a good outcome (mRS 0.1). CONCLUSION: MMCT sensitivity in acute lacunar or infratentorial stroke was poor. But, we found a high specifity and a fairly good sensitivity in territorial infarct detection. In acute stroke patients with normal MMCT findings on admission, a good clinical prognosis can be expected.

Application of combinatorial biocatalysis for a unique ring expansion of dihydroxymethylzearalenone.

Combinatorial biocatalysis was applied to generate a diverse set of dihydroxymethylzearalenone analogs with modified ring structure. In one representative chemoenzymatic reaction sequence, dihydroxymethylzearalenone was first subjected to a unique enzyme-catalyzed oxidative ring opening reaction that creates two new carboxylic groups on the molecule. These groups served as reaction sites for further derivatization involving biocatalytic ring closure reactions with structurally diverse bifunctional reagents, including different diols and diamines. As a result, a library of cyclic bislactones and bislactams was created, with modified ring structures covering chemical space and structure activity relationships unattainable by conventional synthetic means.

Extractive biotransformation for production of metabolites of poorly soluble compounds: synthesis of 32-hydroxy-rifalazil.

A novel reaction system was developed for the production of metabolites of poorly water-soluble parent compounds using mammalian liver microsomes. The system includes the selection and use of an appropriate hydrophobic polymeric resin as a reservoir for the hydrophobic parent compounds and its metabolites. The utility of the extractive biotransformation approach was shown for the production of a low-yielding, synthetically challenging 32-hydroxylated metabolite of the antibiotic rifalazil using mouse liver microsomes. To address the low solubility and reactivity of rifalazil in the predominantly aqueous microsomal catalytic system, a variety of strategies were tested for the enhanced delivery of hydrophobic substrates, including the addition of mild detergents, polyvinylpyrrolidone, glycerol, bovine serum albumin, and hydrophobic polymeric resins. The latter strategy was identified as the most suitable for the production of 32-hydroxy-rifalazil, resulting in up to 13-fold enhancement of the volumetric productivity compared with the standard aqueous system operating at the solubility limit of rifalazil. The production process was optimized for a wide range of reaction parameters; the most important for improving volumetric productivity included the type and amount of the polymeric resin, cofactor recycling system, concentrations of the biocatalyst and rifalazil, reaction temperature, and agitation rate. The optimized extractive biotransformation system was used to synthesize 32-hydroxy-rifalazil on a multimilligram scale.

Reversible derivatization to enhance enzymatic synthesis: chemoenzymatic synthesis of doxorubicin-14-O-esters.

An efficient three-step, chemoenzymatic synthesis of unprotected doxorubicin-14-O-esters from doxorubicin hydrochloride salt is described. The key step is a lipase-catalyzed regioselective transesterification/esterification using commercially available acyl donors and doxorubicin reversibly derivatized with N-alloc to improve substrate loadings. The overall yield is ca. 60% and chromatographic purification is not required, thereby making the process more amenable to scale-up.

Endovascular treatment in proximal and intracranial carotid occlusion 9 hours after symptom onset.

INTRODUCTION: A debate is emerging over whether the treatment time window in acute stroke can be extended beyond 6 h if penumbral tissue can be identified. Treatment decisions are very difficult in cases of tandem proximal carotid occlusion with arterioarterial intracranial embolism. We enter this debate with the present report on a case of atherosclerotic proximal carotid occlusion and resulting periocclusional carotid T embolism that was successfully treated 9 h after symptom onset. METHODS: The case of a 68-year-old man with fluctuating symptoms of right-hemispheric stroke is presented (NIHSS score 12-20 on admission). CT angiography demonstrated proximal carotid occlusion and periocclusional embolism of the entire internal carotid artery (ICA) including the carotid T segment. Penumbral tissue was diagnosed by nonenhanced and perfusion CT imaging 7.5 h after symptom onset. Treatment was initiated 9 h after symptom onset by passing the proximal occlusion with a microcatheter and local administration of recombinant tissue plasminogen activator (rt-PA) into the carotid T segment at the level of posterior communicating artery (PCoA) origin. RESULTS: Recanalization of the ICA and middle cerebral artery was accomplished within 1 h by flow establishment via the PCoA. The atherosclerotic proximal ICA occlusion was not stented due to the risk of embolism from remnant thrombi in the petrous and cavernous ICA segments. Follow-up MRI showed only mild haemorrhagic infarct transformation of the initial infarct core. The patient was discharged from hospital 18 days after treatment with NIHSS score 5. CONCLUSION: If penumbral tissue can be conclusively identified, endovascular treatment in proximal and intracranial tandem occlusion can be successful, even in treatments initiated 6-9 h after stroke onset. If the intracranial flow after recanalization can be established via the circle of Willis, the underlying proximal ICA occlusion may not require treatment.

14-Hydroxylation of opiates: catalytic direct autoxidation of codeinone to 14-hydroxycodeinone.

Codeinone (3) was efficiently and directly converted to 14-hydroxycodeinone (1) by catalytic air oxidation in aqueous solution. A number of simple manganese and copper salts were identified to be effective catalysts, including MnSO4, KMnO4, and CuSO4. An appropriate reducing agent, such as sodium thiosulfate, is required in the reaction mixture presumably for the reduction of a detrimental peroxide intermediate. This discovery allows the more abundant codeine to be employed as the starting material for the synthesis of 14-hydroxylated opiate drugs without recourse to a thebaine-like intermediate. These discoveries were inspired from our study of microbial transformation of codeine to 14-hydroxycodeine by Mycobacterium neoaurum, where we found the actual 14-hydroxylation step is a chemical reaction rather than an enzymatic reaction, as previously believed.

Combinatorial biocatalysis.

The published applications of combinatorial biocatalysis have continued to expand at a growing rate. This is exemplified by the variety of enzyme catalysts and whole-cell catalysts used for the creation of libraries through a wide range of biocatalytic reactions, including acylation, glycosylation, halogenation, oxidation and reduction. These biocatalytic methods add the capability to perform unique chemistries or selective reactions with complex or labile reagents when integrated with classical combinatorial synthesis methods. Thus, applications towards the production of libraries de novo, the expansion of chemically derived combinatorial libraries, and the generation of novel combinatorial reagents for library synthesis can be achieved. Theoretically, these results illustrate what is already evident from nature: that complex, biologically active, structurally diverse compound libraries can be generated through the application of biocatalysis alone or in combination with classical organic synthesis approaches.