Specific stereochemistry of OP-1074 disrupts estrogen receptor alpha helix 12 and confers pure antiestrogenic activity.

Complex tissue-specific and cell-specific signaling by the estrogen receptor (ER) frequently leads to the development of resistance to endocrine therapy for breast cancer. Pure ER antagonists, which completely lack tissue-specific agonist activity, hold promise for preventing and treating endocrine resistance, however an absence of structural information hinders the development of novel candidates. Here we synthesize a small panel of benzopyrans with variable side chains to identify pure antiestrogens in a uterotrophic assay. We identify OP-1074 as a pure antiestrogen and a selective ER degrader (PA-SERD) that is efficacious in shrinking tumors in a tamoxifen-resistant xenograft model. Biochemical and crystal structure analyses reveal a structure activity relationship implicating the importance of a stereospecific methyl on the pyrrolidine side chain of OP-1074, particularly on helix 12.

Sweet taste preferences before and after an intensive medical weight loss intervention.

OBJECTIVE: Medical weight loss could change sweet taste threshold and preferences. The decrease in sweet taste preferences may, in turn, help in the maintenance of weight loss. This study examined the association between sweet taste preferences at baseline and weight change during a medical weight management programme and the impact of diet-induced weight loss on sweet taste preferences. METHODS: Adult patients with body mass index ≥32 kg m-2 were recruited from a medical weight management clinic. Sweet taste preference was assessed using a forced-choice, paired-comparison tracking method before and after a very-low-calorie diet (VLCD). RESULTS: Twenty participants were included in the analysis: mean age was 53.1 (standard deviation [SD]: 11.4) years, and 14 were female. The mean body mass index was 41.4 (SD: 7.5) kg m-2. The median preferred sucrose concentration before VLCD was 0.45 M. Following VLCD, mean change in weight was -13.3 (SD: 6.6) kg, and percentage weight change was -11.3% (SD: 5.9%). Based on mixed models with and without adjustment for demographic factors, diabetes status and smoking history, preferred sucrose concentration at baseline did not predict change in longer-term body weight. The change of preferred sucrose concentration following 12 weeks of VLCD was not significant (P-value 0.95). CONCLUSIONS: Change in weight during and after VLCD was not associated with sweet taste preferences at baseline. After diet-induced weight loss, sweet taste preferences did not change.

Inhibition of enamel erosion and promotion of lesion rehardening by fluoride: a white light interferometry and microindentation study.

OBJECTIVE: The primary aim of the present in vitro studies was to investigate fluoride as an inhibitor of citric acid-mediated demineralization of human enamel and promoter of lesion repair using a combination of white light interferometry, scanning electron microscopy, and microindentation. Secondary aims included investigation of the importance of brushing on bulk tissue loss, and comparison of the relative efficacy of commercially available toothpastes on inhibiting enamel surface softening and rehardening of incipient erosive lesions. METHODS: Resin-mounted polished enamel specimens were prepared from extracted human molars and pre-molars. Mean surface roughness (Sa) and bulk tissue loss following exposure to an erosive challenge, or an erosive challenge plus brushing were investigated using a MicroXAM ADE PhaseShift white light interferometer. Surface morphology was determined using a Zeiss Evo 50 scanning electron microscope (SEM). The utility of fluoride-based treatments to protect against subsequent acid demineralization and to promote remineralization of pre-formed incipient lesions was determined using microindentation-based enamel surface softening and enamel lesion rehardening models. RESULTS: Treating human enamel specimens with Sensodyne Pronamel conferred a clear protective benefit against a subsequent 300-second citric acid challenge as evidenced by the interferometry and SEM data. The increase in Sa and bulk tissue loss caused by an erosive challenge followed by brushing was markedly reduced by pre-treatment with sodium fluoride (NaF) in a concentration-dependent manner. Sensodyne Pronamel statistically outperformed Colgate Sensitive Enamel Protect both in the enamel surface softening model and lesion rehardening model, and conferred statistically superior enamel fluoride uptake. Treatment of erosive lesions with Sensodyne Pronamel resulted in statistically superior rehardening versus two Crest Pro-Health formulations containing stannous fluoride (SnF2) and sodium hexametaphosphate (NaHMP); the latter did not differ significantly from the fluoride-free negative control paste. Sensodyne Pronamel exhibited statistically significant superiority in a human saliva-based lesion rehardening model compared to Zendium Sensitive containing nominally comparable concentrations of NaF, as well as Colgate Sensitive and Colgate Sensitive Multi Protection containing sodium monofluorophosphate (NaMFP). CONCLUSION: The utility of NaF, whether delivered from simple solution or toothpaste, to reduce citric acid-mediated surface roughening and bulk tissue loss has been clearly demonstrated. The effectiveness of Sensodyne Pronamel as an anti-erosion toothpaste has also been demonstrated in various microhardness models. Crest Pro-Health toothpastes containing SnF2 and NaHMP were not statistically differentiable from a fluoride-free control paste in the lesion rehardening model. The latter result indicates that the benefit of fluoride to promote mineral formation is outweighed by the effect of NaHMP as a mineralization inhibitor in this model.

Fluoride penetration from toothpastes into incipient enamel erosive lesions investigated using dynamic secondary ion mass spectrometry.

OBJECTIVE: The primary aim of this study was to assess the utility of dynamic secondary ion mass spectrometry (DSIMS) as a convenient and sensitive technique for determining fluoride uptake and distribution into incipient human enamel erosive lesions in vitro. A secondary aim was to correlate the extent of lesion rehardening following treatment with a toothpaste slurry, with relative fluoride uptake determined by DSIMS. The final aim was to compare fluoride uptake by incipient lesions treated with toothpastes containing different sources of fluoride using DSIMS. METHODS: Relative fluoride uptake into the surface and body of enamel erosive lesions was monitored by DSIMS as a function of fluoride concentration in a series of formulation-matched experimental pastes. Fluoride uptake into lesions that had been subjected to treatment with different toothpaste slurries in a single-treatment enamel lesion rehardening model was also determined, and its relationship with regard to the extent of rehardening and also the fluoride source investigated. RESULTS: Fluoride uptake by incipient erosive lesions treated with toothpastes containing NaF was quantitatively compared by DSIMS and found to be directly proportional to the fluoride concentration over the studied range (0-1400 ppm). Lesion repair observed in a single-treatment lesion rehardening model was positively correlated with the extent of fluoride uptake by the treated lesions. DSIMS was also able to show differences between commercial toothpastes containing different sources of fluoride and their ability to deliver the fluoride into the body of the lesion. The detrimental effect of sodium hexametaphosphate (NaHMP) present in Crest Pro-Health formulations previously reported in the single-treatment lesion rehardening model was also evident from the DSIMS elemental line scans obtained from the lesion cross-sections. CONCLUSION: DSIMS has been shown to be a powerful selective technique for quantifying relative fluoride uptake into enamel erosive lesions, and determining the extent and depth of lesion penetration. The relative efficacy of toothpastes containing fluoride from a variety of sources in the single-treatment lesion rehardening study is positively correlated with fluoride uptake and penetration determined by DSIMS.

Role of macromolecular assembly of enamel matrix proteins in enamel formation.

Unlike other mineralized tissues, mature dental enamel is primarily (> 95% by weight) composed of apatitic crystals and has a unique hierarchical structure. Due to its high mineral content and organized structure, enamel has exceptional functional properties and is the hardest substance in the human body. Enamel formation (amelogenesis) is the result of highly orchestrated extracellular processes that regulate the nucleation, growth, and organization of forming mineral crystals. However, major aspects of the mechanism of enamel formation are not well-understood, although substantial evidence suggests that protein-protein and protein-mineral interactions play crucial roles in this process. The purpose of this review is a critical evaluation of the present state of knowledge regarding the potential role of the assembly of enamel matrix proteins in the regulation of crystal growth and the structural organization of the resulting enamel tissue. This review primarily focuses on the structure and function of amelogenin, the predominant enamel matrix protein. This review also provides a brief description of novel in vitro approaches that have used synthetic macromolecules (i.e., surfactants and polymers) to regulate the formation of hierarchical inorganic (composite) structures in a fashion analogous to that believed to take place in biological systems, such as enamel. Accordingly, this review illustrates the potential for developing bio-inspired approaches to mineralized tissue repair and regeneration. In conclusion, the authors present a hypothesis, based on the evidence presented, that the full-length amelogenin uniquely regulates proper enamel formation through a process of cooperative mineralization, and not as a pre-formed matrix.

Algorithm-based decision rules to safely reduce laboratory test ordering.

PURPOSE: Our study develops decision rules to define appropriate intervals at which repeat tests might be indicated for commonly ordered laboratory tests for hospitalized patients. METHODS: The final data set includes 5,632 adult patients admitted to the University of Virginia Hospital between July 1995 and December 1999. These patients had a hospital length of stay of five days or more and had results recorded for three routinely ordered laboratory tests for each of the first five days of their hospitalization. We use the serum potassium test to illustrate our algorithm-based decision rule methodology. RESULTS: Our decision rule begins with testing on the first two days of hospitalization and allows for repeat testing after observation of any non-normal values. The results show that the algorithm-based decision rule would lead to a 34% reduction for serum potassium tests for the first five days of hospitalization. Only one out of the 5,632 patients in our sample had a critical value that occurred only on a non-test day and, thus, was missed by the algorithm. CONCLUSIONS: The algorithm results are encouraging. We demonstrate that the number of tests can be reduced while missing critical values in only a small fraction of patients. Testing algorithms such as these can be used to reduce laboratory test ordering without compromising the quality of patient care.

Coincident signalling between the Gi/Go-coupled delta-opioid receptor and the Gq-coupled m3 muscarinic receptor at the level of intracellular free calcium in SH-SY5Y cells.

In SH-SY5Y cells, activation of delta-opioid receptors with [D-Pen(2,5)]-enkephalin (DPDPE; 1 microM) did not alter the intracellular free Ca(2+) concentration [Ca(2+)](i). However, when DPDPE was applied during concomitant Gq-coupled m3 muscarinic receptor stimulation by carbachol or oxotremorine-M, it produced an elevation of [Ca(2+)](i). The DPDPE-evoked increase in [Ca(2+)](i) was abolished when the carbachol-sensitive intracellular Ca(2+) store was emptied. There was a marked difference between the concentration-response relationship for the elevation of [Ca(2+)](i) by carbachol (EC(50) 13 microM, Hill slope 1) and the concentration-response relationship for carbachol's permissive action in revealing the delta-opioid receptor-mediated elevation of [Ca(2+)] (EC(50) 0.7 mM; Hill slope 1.8). Sequestration of free G protein beta gamma dimers by transient transfection of cells with a beta gamma binding protein (residues 495-689 of the C terminal tail of G protein-coupled receptor kinase 2) reduced the ability of delta opioid receptor activation to elevate [Ca(2+)](i). However, DPDPE did not elevate either basal or oxotremorine-M-evoked inositol phosphate production indicating that delta-opioid receptor activation did not stimulate phospholipase C. Furthermore, delta-opioid receptor activation did not result in the reversal of muscarinic receptor desensitization, membrane hyperpolarization or stimulation of sphingosine kinase. There was no coincident signalling between the delta-opioid receptor and the lysophosphatidic acid receptor which couples to elevation of [Ca(2+)](i) in SH-SY5Y cells by a PLC-independent mechanism. In SH-SY5Y cells the coincident signalling between the endogenously expressed delta-opioid and m3 muscarinic receptors appears to occur in the receptor activation-Ca(2+) release signalling pathway at a step after the activation of phospholipase C.

Interfacial synthesis of hollow microspheres of mesostructured silica.

Hollow microspheres with ordered mesoporous walls are synthesised under ambient conditions by a simple procedure involving dilution and neutralisation of an aqueous tetraethoxysilane/cetyltrimethylammonium bromide reaction mixture.

MICs of rifampicin and chloramphenicol for mucoid Pseudomonas aeruginosa strains are lower when human lactoferrin is present.

MlCs of rifampicin and chloramphenicol for mucoid strains of Pseudomonas aeruginosa were lower in the presence of human lactoferrin (0.9 mg/mL, the concentration found in cystic fibrosis sputum) than in its absence. MICs for some strains were lowered to clinically achievable levels of the antibiotics, which is compatible with impressions of greater clinical efficacy in pseudomonas infections than would be predicted by standard sensitivity tests. The routine addition of lactoferrin to sensitivity media for testing of cystic fibrosis isolates may give more useful results than conventional tests as in-vivo conditions are more closely simulated.