Discovery of RMC-5552, a Selective Bi-Steric Inhibitor of mTORC1, for the Treatment of mTORC1-Activated Tumors.

Hyperactivation of mTOR kinase by mutations in the PI3K/mTOR pathway or by crosstalk with other mutant cancer drivers, such as RAS, is a feature of many tumors. Multiple allosteric inhibitors of mTORC1 and orthosteric dual inhibitors of mTORC1 and mTORC2 have been developed as anticancer drugs, but their clinical utility has been limited. To address these limitations, we have developed a novel class of "bi-steric inhibitors" that interact with both the orthosteric and the allosteric binding sites in order to deepen the inhibition of mTORC1 while also preserving selectivity for mTORC1 over mTORC2. In this report, we describe the discovery and preclinical profile of the development candidate RMC-5552 and the in vivo preclinical tool compound RMC-6272. We also present evidence that selective inhibition of mTORC1 in combination with covalent inhibition of KRASG12C shows increased antitumor activity in a preclinical model of KRASG12C mutant NSCLC that exhibits resistance to KRASG12C inhibitor monotherapy.

Selective inhibitors of mTORC1 activate 4EBP1 and suppress tumor growth.

The clinical benefits of pan-mTOR active-site inhibitors are limited by toxicity and relief of feedback inhibition of receptor expression. To address these limitations, we designed a series of compounds that selectively inhibit mTORC1 and not mTORC2. These 'bi-steric inhibitors' comprise a rapamycin-like core moiety covalently linked to an mTOR active-site inhibitor. Structural modification of these components modulated their affinities for their binding sites on mTOR and the selectivity of the bi-steric compound. mTORC1-selective compounds potently inhibited 4EBP1 phosphorylation and caused regressions of breast cancer xenografts. Inhibition of 4EBP1 phosphorylation was sufficient to block cancer cell growth and was necessary for maximal antitumor activity. At mTORC1-selective doses, these compounds do not alter glucose tolerance, nor do they relieve AKT-dependent feedback inhibition of HER3. Thus, in preclinical models, selective inhibitors of mTORC1 potently inhibit tumor growth while causing less toxicity and receptor reactivation as compared to pan-mTOR inhibitors.

Controlled drug release to cancer cells from modular one-photon visible light-responsive micellar system.

We present a one-photon visible light-responsive micellar system for efficient, on-demand delivery of small molecules. Release is mediated by a novel class of photochromic material - donor-acceptor Stenhouse adducts (DASAs). We demonstrate controlled delivery of small molecules such as the chemotherapeutic agent (paclitaxel) to human breast cancer cells triggered by micellar switching with low intensity, visible light.

Chemoselective Radical Dehalogenation and C-C Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts.

Despite the number of methods available for dehalogenation and carbon-carbon bond formation using aryl halides, strategies that provide chemoselectivity for systems bearing multiple carbon-halogen bonds are still needed. Herein, we report the ability to tune the reduction potential of metal-free phenothiazine-based photoredox catalysts and demonstrate the application of these catalysts for chemoselective carbon-halogen bond activation to achieve C-C cross-coupling reactions as well as reductive dehalogenations. This procedure works both for conjugated polyhalides as well as unconjugated substrates. We further illustrate the usefulness of this protocol by intramolecular cyclization of a pyrrole substrate, an advanced building block for a family of natural products known to exhibit biological activity.

Simulation as a set-up for technical proficiency: can a virtual warm-up improve live fibre-optic intubation?

BACKGROUND: Fibre-optic intubation (FOI) is an advanced technical skill, which anaesthesia residents must frequently perform under pressure. In surgical subspecialties, a virtual 'warm-up' has been used to prime a practitioner's skill set immediately before performance of challenging procedures. This study examined whether a virtual warm-up improved the performance of elective live patient FOI by anaesthesia residents. METHODS: Clinical anaesthesia yr 1 and 2 (CA1 and CA2) residents were recruited to perform elective asleep oral FOI. Residents either underwent a 5 min, guided warm-up (using a bronchoscopy simulator) immediately before live FOI on patients with predicted normal airways or performed live FOI on similar patients without the warm-up. Subjects were timed performing FOI (from scope passing teeth to viewing the carina) and were graded on a 45-point skill scale by attending anaesthetists. After a washout period, all subjects were resampled as members of the opposite cohort. Multivariate analysis was performed to control for variations in previous FOI experience of the residents. RESULTS: Thirty-three anaesthesia residents were recruited, of whom 22 were CA1 and 11 were CA2. Virtual warm-up conferred a 37% reduction in time for CA1s (mean 35.8 (SD 3.2) s vs. 57 (SD 3.2) s, P<0.0002) and a 26% decrease for CA2s (mean 23 (SD 1.7) s vs. 31 (SD 1.7) s, P=0.0118). Global skill score increased with warm-up by 4.8 points for CA1s (mean 32.8 (SD 1.2) vs. 37.6 (SD 1.2), P=0.0079) and 5.1 points for CA2s (37.7 (SD 1.1) vs. 42.8 (SD 1.1), P=0.0125). Crossover period and sequence did not show a statistically significant association with performance. CONCLUSIONS: Virtual warm-up significantly improved performance by residents of FOI in live patients with normal airway anatomy, as measured both by speed and by a scaled evaluation of skills.

Synthesis of Hindered α-Amino Carbonyls: Copper-Catalyzed Radical Addition with Nitroso Compounds.

The synthesis of sterically hindered anilines has been a significant challenge in organic chemistry. Here we report a Cu-catalyzed radical addition with in situ-generated nitroso compounds to prepare sterically hindered amines directly from readily available materials. The transformation is conducted at room temperature, uses abundant copper salts, and is tolerant of a range of functional groups.

Effect of calcium ions on in vitro pellicle formation from parotid and whole saliva.

The salivary pellicle is a protein-rich, bacteria-free, self-assembling film that adsorbs to all surfaces within the oral cavity. The pellicle has numerous functions that are vital for maintaining oral health. Currently however, there are no commercially available artificial salivas that accurately mimic the complex film forming properties (i.e. film thickness and viscoelasticity) of human saliva. To understand these properties further we have examined the in vitro formation of the salivary pellicle, by adsorbing stimulated parotid saliva (PS) and whole mouth saliva (WMS) from 14 healthy volunteers, onto oxidised silicon surfaces, using a quartz crystal microbalance with dissipation monitoring (QCMD) and a dual polarisation interferometer (DPI). A dramatic impact on the hydrated mass, polymer mass, thickness and polymer concentration of the pellicle for both WMS and PS was observed when the natural calcium concentration of the respective salivas was increased from 0 mM to 10mM. In addition, QCMD data showed that on addition of 10mM calcium the salivary pellicle formed by both PS and WMS became more predominantly elastic. The results presented here also suggest that calcium can easily diffuse in and out of the pellicle, permitting free calcium exchange between the saliva and the adsorbed pellicle under physiological conditions, which may potentially facilitate the mineralisation of enamel.

Reducing the variability between constant-depth film fermenter experiments when modelling oral biofilm.

AIMS: The inherent instabilities associated with the development of multispecies biofilm communities within the constant-depth film fermenter (CDFF) and other microcosm systems can yield unacceptable variability between experiments, which could limit their potential applications in oral microbiology. The extent of this variability needs to be determined and a protocol developed which minimizes it. METHODS AND RESULTS: Two custom-made CDFFs were supplied concurrently with the same inoculation culture, begat from an aliquot of a saliva pool and artificial saliva growth medium via a dual-channel pump. Transformed log(10) data of the viable counts at fixed time points were analysed using the Bland-Altman approach to test for the levels of agreement between two CDFFs running concurrently and those CDFFs run in series. The coefficients(95%) of agreement were lower (i.e. less variable) in the concurrent model than when run in series for total counts of bacteria (1.238 vs 2.124), Lactobacillus spp. (0.517 vs 1.431) and Mutans streptococci (2.817 vs 3.864). Other measures of variability showed a similar trend. CONCLUSIONS: Operating CDFFs concurrently minimizes the degree of difference and variability between them. SIGNIFICANCE AND IMPACT OF THE STUDY: Operating CDFFs concurrently will improve the sensitivity for experiments that seek to determine the effects of a variable, such as a nutritional supplement or antimicrobial agent, and a control.

New strategies for natural products containing chroman spiroketals.

Two cycloaddition strategies are described that lead to various chroman spiroketals from assorted exocyclic enol ethers. Unlike conventional thermodynamic ketalization strategies, the stereochemical outcome for this approach is determined by a kinetic cycloaddition reaction. Thus, the stereochemical outcome reflects the olefin geometry of the starting materials along with the orientation of the associated transition state. However, the initial kinetic product can also be equilibrated by acid catalysis and reconstituted into a thermodynamic stereochemical arrangement. Thus, these strategies uniquely enable synthetic access to either the thermodynamic or kinetic conformation of the spiroketal stereocenter itself. Applications of these strategies in the syntheses of berkelic acid, ß-rubromycin, and paecilospirone are presented along with the use of a chroman spiroketal for the construction of heliespirones A and C.

A strategy for the late-stage divergent syntheses of scyphostatin analogues.

This account details the synthesis of two scyphostatin analogues exhibiting a reactive polar epoxycyclohexenone core and various amide side chains outfitted for late-stage chemical derivatization into the desirable lipophilic tails. Our efforts highlight a key ipso-dearomatization process and provide new insights regarding the incompatibility and orthogonal reactivity of scyphostatin's functional groups. We further showcase the utility of resorcinol derived 2,5-cyclohexadienones as synthetic platforms capable of participating in selective chemical reactivity, and we further demonstrate their potential for rapid elaboration into complex structural motifs.

Interaction between protein allergens and model gastric emulsions.

The observed resistance to pepsinolysis of known food allergens has been suggested as a predictor of their allergenic risk. Consequently, resistance to pepsinolysis has become incorporated into decision tree assessment for potential allergenic risk posed by novel foods. However, existing methods take little account of the interaction between food structure and physiological conditions existing during digestion in vivo. Here we show that a range of protein allergens can adsorb to model stomach emulsions, providing a further means of resisting digestion. We also show that raising the pH and the addition of bile salts to a model stomach emulsion, thereby mimicking the duodenal environment, has the effect of desorbing the adsorbed protein.

Pregnancy discovery and acceptance among low-income primiparous women: a multicultural exploration.

OBJECTIVES: As part of a larger study exploring psychosocial factors that influence self-care and use of health care services during pregnancy, we investigated the process of pregnancy discovery and acceptance among a culturally diverse group of women who had given birth to their first child in the year preceding data collection. METHODS: Eighty-seven low-income women from four cultural groups (African American, Mexican, Puerto Rican, and white) participated in eight focus groups held in their communities. The focus groups were ethnically homogenous and stratified by early and late entry into prenatal care. A social influence model guided the development of focus group questions, and the study followed a participatory action research model, with community members involved in all phases of the research. RESULTS: Issues that emerged from the focus groups as possible influences on timing of pregnancy recognition include the role of pregnancy signs and symptoms and pregnancy risk perception in the discovery process, the role of social network members in labeling and affirming the pregnancy, concerns about disclosure, "planning" status of the pregnancy, and perceived availability of choices for resolving an unintended pregnancy. CONCLUSIONS: The pregnancy discovery process is complex, and when protracted, can potentially result in delayed initiation of both prenatal care and healthful pregnancy behaviors. Enhancing our understanding of pregnancy discovery and acceptance has clear implications for primary and secondary prevention. Future research is needed to further explain the trajectory of pregnancy discovery and acceptance and its influence on health behaviors and pregnancy outcome.

Adsorbed protein secondary and tertiary structures by circular dichroism and infrared spectroscopy with refractive index matched emulsions.

The secondary structure of protein adsorbed at the emulsion interface has been studied in refractive index matched emulsions using the techniques of circular dichroism (CD) and Fourier transform infrared spectroscopy. Bovine serum albumin (BSA) and bovine beta-lactoglobulin (betalg) stabilized emulsions were studied, and the refractive index was altered by the addition of glycerol or polyethylene glycol. The effect of additive on the solution and adsorbed protein structure in addition to the effect of adsorption time was considered. Both adsorption and glycerol addition alter protein secondary structure; however, the majority of secondary structure remains. Small changes are observed in the secondary structure of adsorbed protein with time. Near-ultraviolet CD studies showed the effect of glycerol and adsorption on the aromatic groups. BSA showed small changes both upon the addition of glycerol to protein in solution and upon adsorption. betalg showed slightly larger changes upon the addition of glycerol to protein in solution and a larger change upon adsorption.

Validating the safety of nurse-health advocate services.

Prior to promoting the use of community health care advocates for home visits, it is necessary to evaluate their ability to safely screen for health problems. This study examined trained maternal-child health advocates (MCHAs) who, supervised by professional nurses, conducted maternal-child home visits consisting of health promotion and problem identification. Problems identified by MCHAs were compared to problems identified by professional, validating nurses, who were not part of the service project, on hypothetical home visit situations and during 213 duplicate home visits. There were no significant differences between MCHAs and professional nurses in their identifications of infant health problems, infant health care deficits, other family members' health problems, prenatal care deficits, emotional problems, and substance abuse on either the hypothetical home visits or the duplicate home visits. The validating nurses identified significantly more women's health problems (p = 0.01) and women's health care deficits (p = 0.02) than the MCHAs on the duplicate home visits. These findings validate the safety of using the model of trained community health advocates teamed with registered nurses to screen for infant health problems during home visits.

Comparison between electroglottography and electromagnetic glottography.

Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis.