Nontraumatic aortic blood flow sensing by use of an ultrasonic esophageal probe.

The measurement of blood velocity fields, volume flow, and arterial wall motion in the descending thoracic aorta provides essential hemodynamic information for both research and clinical diagnosis. The close proximity of the esophagus to the aorta in the dog makes it possible to obtain such data nonsurgically using an ultrasonic esophageal probe; however, the accuracy of such a probe is limited if the angle between the sound beam and the flow axis, known as the Doppler angle, is not precisely known. By use of a pulsed Doppler velocity meter (PUDVM) and a triangulation procedure, accurate empirical measurement of the Doppler angle has been obtained, allowing quantification of blood velocity scans across the aorta. Volume flow is obtained by integration of blood velocity profiles and arterial wall motion is measured with an ultrasonic echo tracking device. Accuracy of the probe was substantiated by comparison with ultrasonic and electromagnetic implanted flow cuff measurements. Use of the probe in measurement of blood velocity, volume flow and arterial wall motion at various locations along the 8- and 10-cm length of the descending thoracic aorta in adult beagle dogs is detailed. The simplicity, accuracy, and nontraumatic aspect of the technique should allow increasing use of such a probe in numerous research and clinical applications.     

The pathogen causing Dutch elm disease makes host trees attract insect vectors

Dutch elm disease is caused by the fungal pathogen Ophiostoma novo-ulmi which is transmitted by the native elm bark beetle, Hylurgopinus rufipes. We have found that four semiochemicals (the monoterpene (-)-beta-pinene and the sesquiterpenes (-)-alpha-cubebene, (+)-spiroaxa-5,7-diene and (+)-delta-cadinene) from diseased American elms, Ulmus americana, synergistically attract H. rufipes, and that sesquiterpene emission is upregulated in elm trees inoculated with O. novo-ulmi. The fungus thus manipulates host trees to enhance their apparency to foraging beetles, a strategy that increases the probability of transportation of the pathogen to new hosts.     

Genome-wide association mapping of loci for antipsychotic-induced extrapyramidal symptoms in mice

Tardive dyskinesia (TD) is a debilitating, unpredictable, and often irreversible side effect resulting from chronic treatment with typical antipsychotic agents such as haloperidol. TD is characterized by repetitive, involuntary, purposeless movements primarily of the orofacial region. In order to investigate genetic susceptibility to TD, we used a validated mouse model for a systems genetics analysis geared toward detecting genetic predictors of TD in human patients. Phenotypic data from 27 inbred strains chronically treated with haloperidol and phenotyped for vacuous chewing movements were subject to a comprehensive genomic analysis involving 426,493 SNPs, 4,047 CNVs, brain gene expression, along with gene network and bioinformatic analysis. Our results identified ~50 genes that we expect to have high prior probabilities for association with haloperidol-induced TD, most of which have never been tested for association with human TD. Among our top candidates were genes regulating the development of brain motor control regions (Zic4 and Nkx6-1), glutamate receptors (Grin1 and Grin2a), and an indirect target of haloperidol (Drd1a) that has not been studied as well as the direct target, Drd2.     

Proteomic analysis of mature melanosomes from the retinal pigmented epithelium

The protein content of melanosomes in the retinal pigment epithelium (RPE) was analyzed by mass spectrometry. More than 100 proteins were found to be common to two out of three variations of sample preparation. Some proteins normally associated with other organelles were detected. Several lysosomal enzymes were detected, with the presence of cathepsin D confirmed by immunoelectron microscopy, thus supporting the previously suggested notion that melanosomes may contribute to the degradation of ingested photoreceptor outer segment disks.     

Small-Molecule Inhibitors of Gram-Negative Lipoprotein Trafficking Discovered by Phenotypic Screening

In Gram-negative bacteria, lipoproteins are transported to the outer membrane by the Lol system. In this process, lipoproteins are released from the inner membrane by the ABC transporter LolCDE and passed to LolA, a diffusible periplasmic molecular chaperone. Lipoproteins are then transferred to the outer membrane receptor protein, LolB, for insertion in the outer membrane. Here we describe the discovery and characterization of novel pyridineimidazole compounds that inhibit this process. Escherichia coli mutants resistant to the pyridineimidazoles show no cross-resistance to other classes of antibiotics and map to either the LolC or LolE protein of the LolCDE transporter complex. The pyridineimidazoles were shown to inhibit the LolA-dependent release of the lipoprotein Lpp from E. coli spheroplasts. These results combined with bacterial cytological profiling are consistent with LolCDE-mediated disruption of lipoprotein targeting to the outer membrane as the mode of action of these pyridineimidazoles. The pyridineimidazoles are the first reported inhibitors of the LolCDE complex, a target which has never been exploited for therapeutic intervention. These compounds open the door to further interrogation of the outer membrane lipoprotein transport pathway as a target for antimicrobial therapy.     

The influence of conditions of growth on the endogenous metabolism of Saccharomyces cerevisiae: effect on protein,carbohydrate, sterol and fatty acid content and on viability

The nature of the endogenous reserves of Saccharomyces cerevisiae was examined with respect to conditions of growth, specifically extremes of oxygen tension and carbon source. Cells were grown in batch culture at 30 C under aerobic conditions on a galactose or glucose carbon source and under anaerobic conditions on glucose. The greatest effect of growth conditions on the chemical composition of the cells was on their fatty acid and sterol content.Cells grown under both aerobic and anaerobic conditions mobilised concurrently protein, glycogen, trehalose and fatty acids during a period of 72 hours' starvation under aerobic conditions. The viability of both types of the aerobically grown cells declined to 75% during this period and was not influenced by the initial fatty acid and sterol content of the cells. Cells grown anaerobically showed a more rapid decline in viability which was only 17% after 72 hours' starvation. This loss of viability was not due to a lack of available endogenous reserves but was probably due to an impaired membrane function caused by a deficiency of sterols and unsaturated fatty acids.     

ZW10 links mitotic checkpoint signaling to the structural kinetochore

The mitotic checkpoint ensures that chromosomes are divided equally between daughter cells and is a primary mechanism preventing the chromosome instability often seen in aneuploid human tumors. ZW10 and Rod play an essential role in this checkpoint. We show that in mitotic human cells ZW10 resides in a complex with Rod and Zwilch, whereas another ZW10 partner, Zwint-1, is part of a separate complex of structural kinetochore components including Mis12 and Ndc80-Hec1. Zwint-1 is critical for recruiting ZW10 to unattached kinetochores. Depletion from human cells or Xenopus egg extracts is used to demonstrate that the ZW10 complex is essential for stable binding of a Mad1-Mad2 complex to unattached kinetochores. Thus, ZW10 functions as a linker between the core structural elements of the outer kinetochore and components that catalyze generation of the mitotic checkpoint-derived "stop anaphase" inhibitor.     

Synthesis and characterization of a theranostic vascular disrupting agent for in vivo MR imaging

Colchicine, a known tubulin binding agent and vascular disrupting agent, causes rapid vascular shut down and central necrosis in tumors. The binding of tubulin results in tubulin destabilization, with characteristic cell shape changes and inhibition of cell division, and results in cell death. A gadolinium(III) labeled derivative of colchicine (Gd·DOTA·Colchicinic acid) was synthesized and characterized as a theranostic agent (enabling simultaneous diagnostic/real time MRI contrast imaging). In vitro, Gd·DOTA·Colchicinic acid was shown to initiate cell changes characteristic of tubulin-destabilization in both OVCAR-3 and IGROV-1 ovarian carcinoma cell lines in vitro over a period of 24 h, while maintaining the qualities of the MR imaging tracer. In vivo, Gd·DOTA·Colchicinic acid (200 mg/kg) was shown to induce the formation of central necrosis, which was confirmed ex vivo by histology, in OVCAR-3 subcutaneous tumor xenografts, while simultaneously acting as an imaging agent to promote a significant reduction in the MR relaxation time T(1) (p < 0.05) of tumors 24 h post-administration. Morphological changes within the tumor which corresponded with areas derived from the formation of central necrosis were also present on MR images that were not observed for the same colchicine derivate that was not complexed with gadolinium that also presented with central necrosis ex vivo. However, Gd·DOTA·Colchicinic acid accumulation in the liver, as shown by changes in liver T(1) (p < 0.05), takes place within 2 h. The implication is that Gd·DOTA·Colchicinic acid distributes to tissues, including tumors, within 2 h, but enters tumor cells to lower T(1) times and promotes cell death over a period of up to 24 h. As the biodistribution/pharmacokinetic and pharmacodynamics data provided here is similar to that of conventional colchicines derivatives, such combined data are a potentially powerful way to rapidly characterize the complete behavior of drug candidates in vivo.