A Quantitative Diffuse Reflectance Imaging (QDRI) System for Comprehensive Surveillance of the Morphological Landscape in Breast Tumor Margins

In an ongoing effort to address the clear clinical unmet needs surrounding breast conserving surgery (BCS), our group has developed a next-generation multiplexed optical-fiber-based tool to assess breast tumor margin status during initial surgeries. Specifically detailed in this work is the performance and clinical validation of a research-grade intra-operative tool for margin assessment based on diffuse optical spectroscopy. Previous work published by our group has illustrated the proof-of-concept generations of this device; here we incorporate a highly optimized quantitative diffuse reflectance imaging (QDRI) system utilizing a wide-field (imaging area = 17cm²) 49-channel multiplexed fiber optic probe, a custom raster-scanning imaging platform, a custom dual-channel white LED source, and an astronomy grade imaging CCD and spectrograph. The system signal to noise ratio (SNR) was found to be greater than 40dB for all channels. Optical property estimation error was found to be less than 10%, on average, over a wide range of absorption (μ_a = 0–8.9cm^-1) and scattering (μ_s’ = 7.0–9.7cm^-1) coefficients. Very low inter-channel and CCD crosstalk was observed (2% max) when used on turbid media (including breast tissue). A raster-scanning mechanism was developed to achieve sub-pixel resolution and was found to be optimally performed at an upsample factor of 8, affording 0.75mm spatially resolved diffuse reflectance images (λ = 450–600nm) of an entire margin (area = 17cm²) in 13.8 minutes (1.23cm²/min). Moreover, controlled pressure application at the probe-tissue interface afforded by the imaging platform reduces repeated scan variability, providing <1% variation across repeated scans of clinical specimens. We demonstrate the clinical utility of this device through a pilot 20-patient study of high-resolution optical parameter maps of the ratio of the β-carotene concentration to the reduced scattering coefficient. An empirical cumulative distribution function (eCDF) analysis is used to reduce optical property maps to quantitative distributions representing the morphological landscape of breast tumor margins. The optimizations presented in this work provide an avenue to rapidly survey large tissue areas on intra-operative time scales with improved sensitivity to regions of focal disease that may otherwise be overlooked.     

Inhibitory and disinhibitory effects of psychomotor stimulants and depressants on the sexual behavior of male and female rats

Drugs of abuse comprise several pharmacological classes, including psychomotor stimulants, such as amphetamine and cocaine, and CNS depressants, such as morphine and alcohol. Few studies have examined the effects of those drugs systematically on human sexual behavior, although substantial clinical and epidemiological literatures suggest that drugs in both classes either inhibit sexual responding or can be “prosexual” in certain situations, thereby increasing the potential of risky sexual activity and the spread of sexually transmitted diseases. This paper reviews original data in rats showing that both classes of drug inhibit or disinhibit sexual behavior depending on the animal's baseline level of sexual responding, hormonal status, whether the drug is given acutely or chronically, and whether the animal has learned to inhibit sexual responding toward nonreceptive partners or in the presence of conditioned olfactory cues that predict sexual nonreward.     

Analysis of protein fragmentation inhibition by an MMP-inhibitor in an in vivo model of heart failure using automated chromatography

Proteomic strategies have continued to demonstrate value in studying disease by exploiting new technologies that can develop significant numbers of measurements from single samples. However, using complex samples such as tissues or blood has continued to be problematic due to the presence of major interfering substances. In this study, a process is described that uses denaturing peptide extraction from whole tissue and automated chromatography in order to allow subsequent analysis of more than 1000 tissue-derived peptides per sample. The process was employed to identify cardiac proteins that were spared degradation by administration of a heart-protecting matrix metalloproteinase (MMP) inhibitor (compound SC-621) following experimental myocardial infarction (MI). HPLC peptide fingerprints were developed from rat heart left ventricles and the resultant integrated peak data was compared across experimental animals. Surprisingly, although protein fragmentation was generally increased in MI hearts, the effect of the MMP inhibitor was only observed on a few species. The results from this study demonstrated that whole-tissue sample enrichment and peptide analysis using HPLC could be linked in order to study the effects of new compounds on a disease state. The system is flexible and amenable to improvements such as incorporating detection by mass spectrometry.     

A molecular view on pluripotent stem cells

Pluripotent stem cells are undifferentiated cells that are capable of differentiating to all three embryonic germ layers and their differentiated derivatives. They are transiently found during embryogenesis, in preimplantation embryos and fetal gonads, or as established cell lines. These unique cell types are distinguished by their wide developmental potential and by their ability to be propagated in culture indefinitely, without loosing their undifferentiated phenotype. This short review intends to give a general overview on the pluripotent nature of embryo-derived stem cells with a focus on human embryonic stem cells.     

The chimpanzee M blood-group antigen is a variant of the human M-N glycoproteins

Chimpanzee erythrocytes express strong M but weak, occasional N blood-group activity, as detected by anti-M and anti-N reagents. We have found that the M activity is carried by a major membrane glycoprotein that is similar but not identical to the human MM glycoprotein (glycophorin A). We have isolated and characterized this glycoprotein from erythrocyte membranes of four individual chimpanzees. The purified glycoproteins strongly inhibited agglutination of M cells by rabbit anti-human M sera and only weakly inhibited the agglutination of N cells by rabbit anti-human N sera. They also displayed medium-to-strong inhibitory activity against chimpanzee iso- and crossimmune antisera tested with chimpanzee erythrocytes of various V-A-B-D and W^c specificities, which are known as chimpanzee extensions of the human type M-N system and the Miltenberger counterpart, respectively. Each glycoprotein was cleaved with CNBr into three fragments, whose size, solubility, and composition were analogous to those obtained by similar treatment of the human M-N antigens. The amino-terminal fragment was found to be a glycooctapeptide whose amino acid composition and partial sequence indicated that it is an intermediate form of the human M and N glycooctapeptides. Its carbohydrate content comprised two threonine-linked saccharide units that, although similar in composition to the human threonine-linked units, were fewer in number than the three units found in the corresponding human glycooctapeptides. Structural similarities to the human antigens strongly suggest that the amino terminus bears the major antigenic determinants of the molecule, and the occurrence in this region of numerous, albeit rare, variants among humans and in chimpanzees indicates that the corresponding coding sequence of the structural gene is particularly susceptible to mutational events. We conclude that the chimpanzee M gene product is a variant of the human type and that the chimpanzee gene is an allele of the human polymorphic M-N locus.This research was supported by National Institutes of Health Grants GM 16389 and HL 19011 and March of Dimes Grant 1-661.     

Large P body-like RNPs form in C. elegans oocytes in response to arrested ovulation, heat shock, osmotic stress, and anoxia and are regulated by the major sperm protein pathway

As Caenorhabditis elegans hermaphrodites age, sperm become depleted, ovulation arrests, and oocytes accumulate in the gonad arm. Large ribonucleoprotein (RNP) foci form in these arrested oocytes that contain RNA-binding proteins and translationally masked maternal mRNAs. Within 65 min of mating, the RNP foci dissociate and fertilization proceeds. The majority of arrested oocytes with foci result in viable embryos upon fertilization, suggesting that foci are not deleterious to oocyte function. We have determined that foci formation is not strictly a function of aging, and the somatic, ceh-18, branch of the major sperm protein pathway regulates the formation and dissociation of oocyte foci. Our hypothesis for the function of oocyte RNP foci is similar to the RNA-related functions of processing bodies (P bodies) and stress granules; here, we show three orthologs of P body proteins, DCP-2, CAR-1 and CGH-1, and two markers of stress granules, poly (A) binding protein (PABP) and TIA-1, appear to be present in the oocyte RNP foci. Our results are the first in vivo demonstration linking components of P bodies and stress granules in the germ line of a metazoan. Furthermore, our data demonstrate that formation of oocyte RNP foci is inducible in non-arrested oocytes by heat shock, osmotic stress, or anoxia, similar to the induction of stress granules in mammalian cells and P bodies in yeast. These data suggest commonalities between oocytes undergoing delayed fertilization and cells that are stressed environmentally, as to how they modulate mRNAs and regulate translation.     

Social transmission of novel foraging behavior in bats: frog calls and their referents

The fringe-lipped bat, Trachops cirrhosus, uses prey-emitted acoustic cues (frog calls) to assess prey palatability . Previous experiments show that wild T. cirrhosus brought into the laboratory are flexible in their ability to reverse the associations they form between prey cues and prey quality . Here we asked how this flexibility can be achieved in nature. We quantified the rate at which bats learned to associate the calls of a poisonous toad species with palatable prey by placing bats in three groups: (a) social learning, in which a bat inexperienced with the novel association was allowed to observe an experienced bat; (b) social facilitation, in which two inexperienced bats were presented with the experimental task together; and (c) trial-and-error, in which a single inexperienced bat was presented with the experimental task alone. In the social-learning group, bats rapidly acquired the novel association in an average of 5.3 trials. In the social-facilitation and trial-and-error groups, most bats did not approach the call of the poisonous species after 100 trials. Thus, once acquired, novel associations between prey cue and prey quality could spread rapidly through the bat population by cultural transmission. This is the first case to document predator social learning of an acoustic prey cue.