Pin1 inhibitors: Pitfalls,progress and cellular pharmacology

Compelling data supports the hypothesis that Pin1 inhibitors will be useful for the therapy of cancer: Pin1 deficient mice resist the induction of breast cancers normally evoked by expression of MMTV-driven Ras or Erb2 alleles. While Pin1 poses challenges for drug discovery, several groups have identified potent antagonists by structure based drug design, significant progress has been made designing peptidic inhibitors and a number of natural products have been found that blockade Pin1, notably epigallocatchechin gallate (EGCG), a major flavonoid in green tea. Here we critically discuss the modes of action and likely specificity of these compounds, concluding that a suitable chemical biology tool for probing the function of Pin1 has yet to be found. We conclude by outlining some open questions regarding the target validation of Pin1 and the prospects for identification of improved inhibitors in the future.     

Identification and isolation of a Castellaniella species important during biostimulation of an acidic nitrate- and uranium-contaminated aquifer

Immobilization of uranium in groundwater can be achieved through microbial reduction of U(VI) to U(IV) upon electron donor addition. Microbial community structure was analyzed in ethanol-biostimulated and control sediments from a high-nitrate (>130 mM), low-pH, uranium-contaminated site in Oak Ridge, TN. Analysis of small subunit (SSU) rRNA gene clone libraries and polar lipid fatty acids from sediments revealed that biostimulation resulted in a general decrease in bacterial diversity. Specifically, biostimulation resulted in an increase in the proportion of Betaproteobacteria (10% of total clones in the control sediment versus 50 and 79% in biostimulated sediments) and a decrease in the proportion of Gammaproteobacteria and Acidobacteria. Clone libraries derived from dissimilatory nitrite reductase genes (nirK and nirS) were also dominated by clones related to Betaproteobacteria (98% and 85% of total nirK and nirS clones, respectively). Within the nirK libraries, one clone sequence made up 59 and 76% of sequences from biostimulated sediments but only made up 10% of the control nirK library. Phylogenetic analysis of SSU rRNA and nirK gene sequences from denitrifying pure cultures isolated from the site indicate that all belong to a Castellaniella species; nearly identical sequences also constituted the majority of biostimulated SSU rRNA and nirK clone libraries. Thus, by combining culture-independent with culture-dependent techniques, we were able to link SSU rRNA clone library information with nirK sequence data and conclude that a potentially novel Castellaniella species is important for in situ nitrate removal at this site.     

Suburbanization and segregation in the United States: 1970–2010

Analysis of trends in the suburbanization of whites, blacks, Asians, and Hispanics reveal that all groups are becoming more suburbanized, though the gap between whites and minorities remains large. Although central cities have made the transition to a majority-minority configuration, suburbs are still overwhelmingly white. Levels of minority-white segregation are nonetheless lower in suburbs than in cities. Blacks remain the most segregated group at both locations. Black segregation and isolation levels are declining in cities and suburbs; however, while Hispanic and Asian segregation levels have remained stable, spatial isolation levels have risen. Multivariate analyses suggest that Hispanics achieve desegregation indirectly by using socio-economic achievements to gain access to less-segregated suburban communities and directly by translating their status attainments into residence in white neighbourhoods. Blacks do not achieve desegregation indirectly through suburbanization and they are much less able than Hispanics to use their socio-economic attainments directly to enter white neighbourhoods.     

Testing Initiatives Increase Rates of HIV Diagnosis in Primary Care and Community Settings: An Observational Single-Centre Cohort Study

Objectives

The primary objective was to examine trends in new HIV diagnoses in a UK area of high HIV prevalence between 2000 and 2012 with respect to site of diagnosis and stage of HIV infection.

Design

Single-centre observational cohort study.

Setting

An outpatient HIV department in a secondary care UK hospital.

Participants

1359 HIV-infected adults.

Main Outcome Measures

Demographic information (age, gender, ethnicity, and sexual orientation), site of initial HIV diagnosis (Routine settings such as HIV/GUM clinics versus Non-Routine settings such as primary care and community venues), stage of HIV infection, CD4 count and seroconversion symptoms were collated for each participant.

Results

There was a significant increase in the proportion of new HIV diagnoses made in Non-Routine settings (from 27.0% in 2000 to 58.8% in 2012; p<0.001). Overall there was a decrease in the rate of late diagnosis from 50.7% to 32.9% (p=0.001). Diagnosis of recent infection increased from 23.0% to 47.1% (p=0.001). Of those with recent infection, significantly more patients were likely to report symptoms consistent with a seroconversion illness over the 13 years (17.6% to 65.0%; p<0.001).

Conclusions

This is the first study, we believe, to demonstrate significant improvements in HIV diagnosis and a shift in diagnosis of HIV from HIV/GUM settings to primary practice and community settings due to multiple initiatives.     

Improved fermentation processes for NS0 cell lines expressing human antibodies and glutamine synthetase

To meet the increasing requirement for therapeutic antibodies to conduct clinical trials, an enhanced culture medium and fed-batch process was developed for GS-NS0 cell lines. This process was shown to produce high concentrations of monoclonal antibodies for several cell lines expressing different antibodies. Cells were adapted to growth in a glutamine- and serum-free medium containing bovine serum albumin (BSA), cholesterol, and transferrin. A number of amino acids were found to be depleted during cell culture. The concentrations of these amino acids were increased, and further cell culture analyses were performed. This process of cell growth and analysis was repeated over multiple cycles until no depletion was detected. This resulted in an amino acid supplement that was shown to be generic and enhanced antibody productivity up to 5-fold for the three cell lines tested. Transferrin was replaced using tropolone, a lipophilic iron chelator and ferric ammonium citrate. Cell growth was equivalent to that in transferrin-containing medium over the wide ranges tested. A concentrated feed solution, based on the amino acid supplement and the components of the serum- and protein-free supplements, was formulated. Addition of this feed in response to metabolic requirements resulted in a harvest titer a further 2-fold higher than the enhanced culture medium. Harvest antibody titers of up to 600 mg/L were achieved for three cell lines expressing different antibodies, representing an increase of 10-fold over the starting concentrations.     

A refined blood collection method for quantifying corticosterone

In many rodent laboratories, blood samples are collected from rats using the tail vein nick procedure and analyzed to quantify blood corticosterone levels as an indicator of stress. The standard method of corticosterone quantification often requires the collection of a relatively large volume of blood, followed by the extraction of the blood plasma. An alternative blood sampling method requires the collection of only a drop of blood on paper (the 'drop' method), minimizing handling of the animals, and does not require plasma extraction. The authors aimed to validate the drop method of blood sampling for use in corticosterone quantification. They induced stress in rats by cerebral ischemia, collected blood samples at various intervals using both the drop method and the plasma extraction method and then quantified corticosterone by radioimmunoassay. Corticosterone levels of the ischemic rats were compared with those of sham-operated rats and those of ischemic rats that had been given metyrapone, a glucocorticoid synthesis inhibitor, prior to vessel occlusion. Blood corticosterone levels in the samples obtained from the same animal using the two different methods were highly correlated for all rats. The authors further provide a regression model that can be used to predict plasma corticosterone values from those obtained from the drop blood samples. Quantification of corticosterone from only a small drop of blood has many practical and ethical advantages and should be considered as an alternative to standard methods.     

Atomic Layer Deposition of CdS Quantum Dots for Solid‐State Quantum Dot Sensitized Solar Cells

Functioning quantum dot (QD) sensitized solar cells have been fabricated using the vacuum deposition technique atomic layer deposition (ALD). Utilizing the incubation period of CdS growth by ALD on TiO₂, we are able to grow QDs of adjustable size which act as sensitizers for solid‐state QD‐sensitized solar cells (ssQDSSC). The size of QDs, studied with transmission electron microscopy (TEM), varied with the number of ALD cycles from 1‐10 nm. Photovoltaic devices with the QDs were fabricated and characterized using a ssQDSSC device architecture with 2,2',7,7'‐tetrakis‐(N,N‐di‐p methoxyphenylamine) 9,9'‐spirobifluorene (spiro‐OMeTAD) as the solid‐state hole conductor. The ALD approach described here can be applied to fabrication of quantum‐confined structures for a variety of applications, including solar electricity and solar fuels. Because ALD provides the ability to deposit many materials in very high aspect ratio substrates, this work introduces a strategy by which material and optical properties of QD sensitizers may be adjusted not only by the size of the particles but also in the future by the composition.