Results of automatic image registration are dependent on initial manual registration

Measurement of static alignment of articulating joints is of clinical benefit and can be determined using image-based registration. We propose a method that could potentially improve the outcome of image-based registration by using initial manual registration. Magnetic resonance images of two wrist specimens were acquired in the relaxed position and during simulated grasp. Transformations were determined from voxel-based image registration between the two volumes. The volumes were manually aligned to match as closely as possible before auto-registration, from which standard transformations were obtained. Then, translation/rotation perturbations were applied to the manual registration to obtain altered initial positions, from which altered auto-registration transformations were obtained. Models of the radiolunate joint were also constructed from the images to simulate joint contact mechanics. We compared the sensitivity of transformations (translations and rotations) and contact mechanics to altering the initial registration condition from the defined standard. We observed that with increasing perturbation, transformation errors appeared to increase and values for contact force and contact area appeared to decrease. Based on these preliminary findings, it appears that the final registration outcome is sensitive to the initial registration.     

A Cross-Sectional Epidemiological Study of Prevalence and Severity of Bit-Induced Oral Trauma in Polo Ponies and Race Horses

Bit and bridle accessories improperly fitted in ridden horses can cause oral trauma such as bone spurs, commissure ulceration, and tongue lacerations. This study was used to identify, grade, and compare the types of oral traumas commonly found within polo ponies and race horses. Injuries were assessed visually and by palpation on the tongue, lips’ commissures, and interdental space. A total of 50 polo ponies and 50 race horses were sampled in the South of England. A Poisson model was successfully fitted to the data (p < .001), and the variables of discipline (p < .001), injury type (p < .001), and age (p < .001) were significant. Race horses with snaffle bits were predisposed to significantly higher severities and prevalence of oral trauma than were polo ponies in gag bits. Only polo ponies were observed with tongue trauma. Race horses had higher severities of injuries in the commissures and bone spurs. Positive correlations were found between age and/or time in sport and induced biting injuries. Polo ponies had been playing longer before the occurrence of injuries.     

An Improved Isolation Procedure for the Gas Chromatographic Analysis of Urinary Polyamines

The isolation of polyamines from urinary hydrolysates in a sufficiently pure state for subsequent analysis by gas chromatography has proved to be difficult. However, by using columns of Porapak-Q and ion-exchange resins, urinary hydrolysates are readily purified and formation of trifluoroacetyl derivatives of polyamines proceeds in high yield without carryover of artifacts in the gas chromatographic elution profile. Good yields from the trifluoroacetylation reaction are not achieved if large quantities of salts or urinary pigments are present. By obtaining the polyamine carbonates in the final stages of the method described, the trifluoroacetylation reaction yields excellent derivatives of nanogram or microgram amounts, particularly after standing over-night at room temperature. The procedure described in detail should permit routine urinary polyamine analysis where rapidity, ease of handling many samples, freedom from complications and artifacts are a consideration. The recent reports by Russell^{1, 2} that the urinary excretion of polyamines are greatly elevated in cancer patients has stimulated interest in these compounds as possible biological “markers” for the diagnosis of cancer. The polyamines usually considered are: putrescine, 1, 4-diaminobutane; cadaverine, 1, 5-diaminopentane; spermidine, and spermine. An extensive literature has developed over the last 50 years concerning the isolation and determination of polyamines including many excellent reviews. ^3–5 However, the isolation and determination of small quantities of polyamines from biological sources has proven to be difficult. This has led to conflicting conclusions among investigators as to which polyamine is the major excretion product in the urine of cancer patients. ^{2, 6, 7, 8} The following report presents in detail a new procedure of isolation of urinary polyamines in high yield and pure state that facilitates quantitation of these amines by gas chromatography.     

Molecular taxonomy and naming of five cryptic species of Alviniconcha snails (Gastropoda: Abyssochrysoidea) from hydrothermal vents

Large symbiont-hosting snails of the genus Alviniconcha (Gastropoda: Abyssochrysidae) are among the dominant inhabitants of hydrothermal vents in the Western Pacific and Indian oceans. The genus was originally described as monotypic, but unique DNA sequences for mitochondrial genes revealed six distinct evolutionary lineages that we could not distinguish based on external morphology. Subsumed under the name Alviniconcha hessleri Okutani & Ohta, the distinct allopatric and sympatric lineages have been assigned placeholder epithets that complicate scientific communications. Based on the present multi-gene sequence data, we hereby describe five Alviniconcha species (in the order of their discovery) – A. kojimai sp. nov., A. boucheti sp. nov., A. marisindica sp. nov., A. strummeri sp. nov. and A. adamantis sp. nov. Thus, we restrict application of the name A. hessleri to specimens that are genetically similar (≥95% for COI) to those found at localities in the Mariana Trough. Single distinct Alviniconcha species inhabit vent fields along the Central Indian Ridge, the Mariana volcanic arc, and the Mariana back-arc basin, whereas vents in the Manus, Fiji and Lau back-arc basins may host two or three additional species. Formal recognition of these species facilitates future attempts to assess their physiological differences and symbiont associations. Furthermore, their reported distributions have significant biogeographic implications, affecting estimates of the diversity within and overlap among Indo-Pacific vent localities.

http://zoobank.org/urn:lsid:zoobank.org:pub:1E4B2E71-9F1D-479E-9A9A-22A9E303AAE5     

Synthesis of 4′-Trifluoromethyl Nucleoside Analogs

Abstract

A strategy based on the use of (trifluoromethyl) trimethylsilane for introduction of the trifluoromethyl group at the C-4 of ribose has been developed and utilized in the synthesis of various novel 4′-trifluoromethylated nucleoside analogs. Screening of these analogs against HIV did not reveal significant biological activity.     

Uric Acid: The Oxidant-Antioxidant Paradox

Uric acid, despite being a major antioxidant in the human plasma, both correlates and predicts development of obesity, hypertension, and cardiovascular disease, conditions associated with oxidative stress. While one explanation for this paradox could be that a rise in uric acid represents an attempted protective response by the host, we review the evidence that uric acid may function either as an antioxidant (primarily in plasma) or pro-oxidant (primarily within the cell). We suggest that it is the pro-oxidative effects of uric acid that occur in cardiovascular disease and may have a contributory role in the pathogenesis of these conditions.     

Inactivation of Nitric Oxide by Uric Acid

The 1980 identification of nitric oxide (NO) as an endothelial cell-derived relaxing factor resulted in an unprecedented biomedical research of NO and established NO as one of the most important cardiovascular, nervous and immune system regulatory molecule. A reduction in endothelial cell NO levels leading to “endothelial dysfunction” has been identified as a key pathogenic event preceding the development of hypertension, metabolic syndrome, and cardiovascular disease. The reduction in endothelial NO in cardiovascular disease has been attributed to the action of oxidants that either directly react with NO or uncouple its substrate enzyme. In this report, we demonstrate that uric acid (UA), the most abundant antioxidant in plasma, reacts directly with NO in a rapid irreversible reaction resulting in the formation of 6-aminouracil and depletion of NO. We further show that this reaction occurs preferentially with NO even in the presence of oxidants peroxynitrite and hydrogen peroxide and that the reaction is at least partially blocked by glutathione. This study shows a potential mechanism by which UA may deplete NO and cause endothelial dysfunction, particularly under conditions of oxidative stress in which UA is elevated and intracellular glutathione is depleted.     

Identification and Quantification of AKT Isoforms and Phosphoforms in Breast Cancer Using a Novel Nanofluidic Immunoassay

Breast cancer subtype-specific molecular variations can dramatically affect patient responses to existing therapies. It is thought that differentially phosphorylated protein isoforms might be a useful prognostic biomarker of drug response in the clinic. However, the accurate detection and quantitative analysis of cancer-related protein isoforms and phospho-isoforms in tumors are limited by current technologies. Using a novel, fully automated nanocapillary electrophoresis immunoassay (NanoPro^TM 1000) designed to separate protein molecules based on their isoelectric point, we developed a reliable and highly sensitive assay for the detection and quantitation of AKT isoforms and phosphoforms in breast cancer. This assay enabled the measurement of activated AKT1/2/3 in breast cancer cells using protein produced from as few as 56 cells. Importantly, we were able to assign an identity for the phosphorylated S473 phosphoform of AKT1, the major form of activated AKT involved in multiple cancers, including breast, and a current focus in clinical trials for targeted intervention. The ability of our AKT assay to detect and measure AKT phosphorylation from very low amounts of total protein will allow the accurate evaluation of patient response to drugs targeting activated PI3K-AKT using scarce clinical specimens. Moreover, the capacity of this assay to detect and measure all three AKT isoforms using one single pan-specific antibody enables the study of the multiple and variable roles that these isoforms play in AKT tumorigenesis.Activation of the PI3K-AKT signaling pathway is one of the most common events in cancer (1, 2). Pathway activation can confer a number of advantages to the cancer cells, including enhanced proliferation and survival (1, 2). Multiple mechanisms exist by which the pathway may become activated, including amplification or activation of receptor tyrosine kinases (e.g. ERBB2 in breast and EGFR in lung tumors), mutation of the catalytic or regulatory subunits of PI3K (e.g. PIK3CA in colorectal and breast tumors), loss of the negative regulator PTEN (e.g. mutation in prostate and melanoma), and gain of function of AKT (e.g. amplification or mutation in breast and pancreatic tumors) (reviewed in Refs. 1 and 2).AKT represents a central node in the PI3K signaling cascade (3). AKT is recruited to the cell membrane via its pleckstrin homology domain when PI3K phosphorylates PIP₂ to form PIP₃ (4, 5). Following recruitment, AKT is phosphorylated by PDK1 and the rictor-mTOR complex, resulting in conformational changes and activation of the protein (5–8). Multiple studies have shown that the phosphorylation of AKT leads to the phosphorylation and activation of downstream effectors of the signaling pathway, such as mTOR complex 1 and S6K (reviewed in Ref. 1). The central role of this pathway in cancer is further underscored by the efforts of multiple pharmaceutical companies that have developed inhibitors against AKT as potential anti-oncogenic therapeutics (9).Despite the importance of AKT in growth and survival signaling in cancer, there are surprisingly few data that address the specific roles played in growth and survival by the multiple AKT family members (AKT-1, -2, and -3) and different phosphorylation and putative phosphorylation sites that can potentially activate the protein. Western blot analysis has been the foundation of most AKT studies, but in many cases pan-AKT antibodies have been employed that fail to distinguish between the different AKT isoforms. Recent siRNA silencing studies have indicated distinct functions for different AKT family members within a cell (10, 11). Moreover, there is evidence in breast cancer that the three isoforms exhibit different localizations and therefore must have at least partially distinct functions (12). Similarly, evidence is mounting for multiple phosphorylation sites in AKT beyond the two most studied phosphorylation events (Thr-308 and Ser-473) (5–8). Phosphorylation at serine and threonine residues at Thr-72 and Ser-246 may be required for the activation or regulation of kinase activity (13). The functional significance of constitutive phosphorylation of Ser-124 and Thr-450 is still unknown (14). Finally, there is evidence that phosphorylation of tyrosine residues at Tyr-315 and Tyr-326 is required for full kinase activity (15).Analysis of such phospho- and isoform-specific activation often requires complicated in-depth analyses using large quantities of proteins, purified recombinant protein, immunoprecipitation, incorporation of ³²P isotopes, and/or mass spectroscopy, which makes such studies more difficult to perform and not easily adaptable to clinical specimens. Thus, better methods are required for the accurate assessment of both phosphoform and isoform usage in cells with an activated PI3K-AKT pathway and the effects of pathway inhibitors using relatively small amounts of starting material. We describe here the development of such an assay using nanocapillary-based isoelectric focusing (16). This approach allows the separation of AKT into distinct peaks that correspond to different iso- and phosphoforms using a small amount of starting material and a single pan-specific antibody. This approach should allow for more accurate determinations of isoform usage in different cell types, as well as of changes in phosphorylation states in response to pathway inhibition, including in clinical specimens.