Human Induced Pluripotent Stem Cell Derived Neuronal Cells Cultured on Chemically-Defined Hydrogels for Sensitive In Vitro Detection of Botulinum Neurotoxin.

Botulinum neurotoxin (BoNT) detection provides a useful model for validating cell-based neurotoxicity screening approaches, as sensitivity is dependent on functionally competent neurons and clear quantitative endpoints are available for correlating results to approved animal testing protocols. Here, human induced pluripotent stem cell (iPSC)-derived neuronal cells were cultured on chemically-defined poly(ethylene glycol) (PEG) hydrogels formed by "thiol-ene" photopolymerization and tested as a cell-based neurotoxicity assay by determining sensitivity to active BoNT/A1. BoNT/A1 sensitivity was comparable to the approved in vivo mouse bioassay for human iPSC-derived neurons and neural stem cells (iPSC-NSCs) cultured on PEG hydrogels or treated tissue culture polystyrene (TCP) surfaces. However, maximum sensitivity for BoNT detection was achieved two weeks earlier for iPSC-NSCs that were differentiated and matured on PEG hydrogels compared to TCP. Therefore, chemically-defined synthetic hydrogels offer benefits over standard platforms when optimizing culture conditions for cell-based screening and achieve sensitivities comparable to an approved animal testing protocol.

Outcomes among chronically ill adults in a medical home prototype.

OBJECTIVES: To compare quality, utilization, and cost outcomes for patients with selected chronic illnesses at a patient-centered medical home (PCMH) prototype site with outcomes for patients with the same chronic illnesses at 19 nonintervention control sites. STUDY DESIGN: Nonequivalent pretest-posttest control group design. METHODS: PCMH redesign results were investigated for patients with preexisting diabetes, hypertension, and/or coronary heart disease. Data from automated databases were collected for eligible enrollees in an integrated healthcare delivery system. Multivariable regression models tested for adjusted differences between PCMH patients and controls during the baseline and follow-up periods. Dependent measures under study included clinical processes and, outcomes, monthly healthcare utilization, and costs. RESULTS: Compared with controls over 2 years, patients at the PCMH prototype clinic had slightly better clinical outcome control in coronary heart disease (2.20 mg/dL lower mean low-density lipoprotein cholesterol; P <.001). PCMH patients changed their patterns of primary care utilization, as reflected by 86% more secure electronic message contacts (P <.001), 10% more telephone contacts (P = .003), and 6% fewer in-person primary care visits (P <.001). PCMH patients had 21% fewer ambulatory care-sensitive hospitalizations (P <.001) and 7% fewer total inpatient admissions (P = .002) than controls. During the 2-year redesign, we observed 17% lower inpatient costs (P <.001) and 7% lower total healthcare costs (P <.001) among patients at the PCMH prototype clinic. CONCLUSIONS: A clinic-level population-based PCMH redesign can decrease downstream utilization and reduce total healthcare costs in a subpopulation of patients with common chronic illnesses.

Evaluation of adamantane hydroxamates as botulinum neurotoxin inhibitors: synthesis, crystallography, modeling, kinetic and cellular based studies.

Botulinum neurotoxins (BoNTs) are the most lethal biotoxins known to mankind and are responsible for the neuroparalytic disease botulism. Current treatments for botulinum poisoning are all protein based and thus have a limited window of treatment opportunity. Inhibition of the BoNT light chain protease (LC) has emerged as a therapeutic strategy for the treatment of botulism as it may provide an effective post exposure remedy. Using a combination of crystallographic and modeling studies a series of hydroxamates derived from 1-adamantylacetohydroxamic acid (3a) were prepared. From this group of compounds, an improved potency of about 17-fold was observed for two derivatives. Detailed mechanistic studies on these structures revealed a competitive inhibition model, with a K(i)=27 nM, which makes these compounds some of the most potent small molecule, non-peptidic BoNT/A LC inhibitors reported to date.

Impact on seniors of the patient-centered medical home: evidence from a pilot study.

PURPOSE: To assess the impact on health care cost and quality among seniors of a patient-centered medical home (PCMH) pilot at Group Health Cooperative, an integrated health care system in Washington State. DESIGN AND METHODS: A prospective before-and-after evaluation of the experience of seniors receiving primary care services at 1 pilot clinic compared with seniors enrolled at the remaining 19 primary care clinics owned and operated by Group Health. Analyses of secondary data on quality and cost were conducted for 1,947 seniors in the PCMH clinic and 39,396 seniors in the 19 control clinics. Patient experience with care was based on survey data collected from 487 seniors in the PCMH clinic and of 668 in 2 specific control clinics that were selected for their similarities in organization and patient composition to the pilot clinic. RESULTS: After adjusting for baseline, seniors in the PCMH clinic reported higher ratings than controls on 3 of 7 patient experience scales. Seniors in the PCMH clinic had significantly greater quality outcomes over time, but this difference was not significant relative to control. PCMH patients used more e-mail, phone, and specialist visits but fewer emergency services and inpatient admissions for ambulatory care sensitive conditions. At 1 and 2 years, the PCMH and control clinics did not differ significantly in overall costs. IMPLICATIONS: A PCMH redesign can be associated with improvements in patient experience and quality without increasing overall cost.

Comparison of the primary rat spinal cord cell (RSC) assay and the mouse bioassay for botulinum neurotoxin type A potency determination.

INTRODUCTION: Botulinum neurotoxin (BoNT) type A is increasingly used in humans for pharmaceutical and cosmetic purposes. Currently, the standard assay used to determine potency of clinical samples, and the only assay approved by the FDA, is the in vivo mouse bioassay (MBA). However, due to several drawbacks of this assay (relatively large error, high cost, no standardization, requirement of high technical expertise, and use of large numbers of mice), there is an increasing need to replace this assay. A cell-based assay using primary rat spinal cord cells (RSC assay) has been previously reported to sensitively detect purified botulinum neurotoxin type A, and requires all biological properties of the toxin for detection. METHODS: This study presents data on quantitative detection of potency of purified BoNT/A by a cell-based assay, using primary rat spinal cord cells (RSC assay). The sensitivity and error rate of the RSC assay was directly compared to the currently used mouse bioassay by repeated testing of the same purified BoNT/A sample by both assays. In addition, the potency of several samples of purified BoNT/A of unknown activity was determined in parallel by RSC assay and MBA. RESULTS: The results indicate sensitivity of the RSC assay similar to the mouse bioassay, high reproducibility, and a lower error rate than the mouse bioassay. Direct comparison of potency determination of several purified BoNT/A samples by RSC assay and MBA resulted in very similar values, indicating very good correlation. DISCUSSION: These data support the use of a cell-based assay for potency determination of purified BoNT/A as an alternative to the mouse bioassay.

Toosendanin: synthesis of the AB-ring and investigations of its anti-botulinum properties (Part II).

Botulinum neurotoxins (BoNTs) are the etiological agents responsible for botulism, a disease characterized by peripheral neuromuscular blockade and a characteristic flaccid paralysis of humans. The natural product toosendanin, a limonoid, is a traditional Chinese medicine that has reported anti-botulinum properties in animal models. Toosendanin effectively inhibits the biological activity of BoNT/A in neuronal cells at concentrations of 200 nM, and partial inhibition can be observed with concentrations as low as 8 nM. Mechanistically, toosendanin's inhibition is due to prevention of transduction of the BoNT LC through the HC channel. Intriguing questions as to the molecular architecture of toosendanin as related to its anti-botulinum properties have focused our attention on a synthesis of toosendanin's unusual AB-ring, containing a unique bridged hemi-acetal. Within the current work, a synthetic strategy allowing access to the AB-fragment of toosendanin was achieved from a trans-decalin system. In addition, this fragment was examined for its modulation of BoNT/A intoxication in a rat spinal cord cellular assay.

Function-oriented synthesis applied to the anti-botulinum natural product toosendanin.

Botulinum neurotoxins (BoNTs) are the etiological agents responsible for botulism, a disease characterized by peripheral neuromuscular blockade and a characteristic flaccid paralysis of humans. The natural product toosendanin is a traditional Chinese medicine which has been reported to have anti-botulinum properties in animal models. To establish what chemical functionalities are necessary for the anti-botulinum properties found within toosendanin, a study was initiated with the goal of using function-oriented synthesis (FOS) as a strategy to begin to unravel toosendanin's powerful anti-botulinum properties. From these studies a new synthetic strategy is put forth allowing access to a 4-acetoxy CD fragment analogue (14) of toosendanin, which was achieved from mesityl oxide and acetylacetone in 14 steps. Animal studies on this fragment are also reported.

Bimodal modulation of the botulinum neurotoxin protein-conducting channel.

Clostridium botulinum neurotoxin (BoNT) is the causative agent of botulism, a neuroparalytic disease. We describe here a semisynthetic strategy to identify inhibitors based on toosendanin, a traditional Chinese medicine reported to protect from BoNT intoxication. Using a single molecule assay of BoNT serotypes A and E light chain (LC) translocation through the heavy chain (HC) channel in neurons, we discovered that toosendanin and its tetrahydrofuran analog selectively arrest the LC translocation step of intoxication with subnanomolar potency, and increase the unoccluded HC channel propensity to open with micromolar efficacy. The inhibitory profile on LC translocation is accurately recapitulated in 2 different BoNT intoxication assays, namely the mouse protection and the primary rat spinal cord cell assays. Toosendanin has an unprecedented dual mode of action on the protein-conducting channel acting as a cargo-dependent inhibitor of translocation and as cargo-free channel activator. These results imply that the bimodal modulation by toosendanin depends on the dynamic interactions between channel and cargo, highlighting their tight interplay during the progression of LC transit across endosomes.

Arginine Promotes Toxin Formation in Cheddar Cheese by Clostridium botulinum.

The production of botulinal toxin by a mixture of spores of Clostridium botulinum types A and B was evaluated in Cheddar cheese supplemented with L-arginine (1% wt/wt) and containing one of three levels of sodium chloride (0, 0.9, or 1.8%). Botulinal toxin was formed in cheeses containing an increased level of L-arginine (1%) and reduced levels of sodium chloride (0 or 0.9%). No toxin was formed in Cheddar with arginine and 1.8% salt or in any of the cheeses not supplemented with arginine. The pH increased from 5.05-5.2 to 5.7-6.0 in the cheeses with increased arginine, but the pH change alone did not permit growth of C. botulinum . Metabolism of arginine may also have promoted the synthesis of compatible metabolites for salt resistance. The results indicate that an important factor supporting growth of C. botulinum in cheese is the availability of L-arginine.