The neural correlates of perceptual load induced attentional selection: an fMRI study

The neural correlates of perceptual load induced attentional selection were investigated in an functional magnetic resonance imaging (fMRI) experiment in which attentional selection was manipulated through the variation of perceptual load in target search. Participants searched for a vertically or horizontally oriented bar among heterogeneously (the high load condition) or homogeneously (the low load condition) oriented distractor bars in the central display, which was flanked by a vertical or horizontal bar presented at the left or the right periphery. The search reaction times were longer when the central display was of high load than of low load, and were longer when the flanker was incongruent than congruent with the target. Importantly, the flanker congruency effect was manifested only in the low load condition, not in the high load condition, indicating that the perceptual load in target search determined whether the task-irrelevant flanker was processed. Imaging analyses revealed a set of fronto-parietal regions having higher activations in the high than in the low load condition. Anterior cingulate cortex (ACC) was more activated for the incongruent than for the congruent trials. Moreover, ACC and bilateral anterior insula were sensitive to the interaction between perceptual load and flanker congruency such that the activation differences between the incongruent and congruent conditions were significant in the low, but not in the high load condition. These results are consistent with the claim that ACC and bilateral anterior insula may exert executive control by selectively biasing processing in favor of task-relevant information and this biasing depends on the resources currently available to the control system.

OFF bipolar cells express distinct types of dendritic glutamate receptors in the mouse retina

Parallel representations of the visual world are already established at the very first synapse of the visual system. Cone photoreceptors, which hyperpolarize in response to light, forward the visual signal onto distinct types of ON and OFF cone bipolar cells (BCs). In the case of OFF BCs, the glutamatergic cone input is integrated by ionotropic glutamate receptors, giving rise to a sign-preserving mode of synaptic transmission. The combination of glutamate receptor (GluR) subunits, i.e. AMPA or kainate subunits, importantly contributes to shaping the OFF bipolar cells' distinct response properties. The mouse is one of the few mammals in which the (most likely) complete set of (five) retinal OFF BC types is identified. However, it is not clear which GluR subtypes are expressed by the different mouse OFF BC types. We addressed this question by combining immunolabeling, electrical whole-cell recordings and pharmacology, and present evidence that the different types of OFF BCs express distinct types of glutamate receptors: Type 1 BCs exclusively expressed AMPA receptors, whereas type 2 and type 3a BCs expressed kainate receptors of different subunit compositions. Additionally, we found that two OFF BC types (3b and 4) very likely express both AMPA and kainate receptors but, interestingly, the two receptor subunits were not co-localized at the same dendritic site. The complex, BC type-specific expression pattern of GluRs we describe here supports their essential role in establishing parallel pathways at the first synapse of the mouse visual system.

First Report of Pseudomonas cichorii Causing Leaf Spot of Stevia Detected in Florida

During a routine nursery inspection in Hernando County, Florida in July 2011, leaf spot symptoms were observed on the popular sugar substitute stevia (Stevia rebaudiana). Spots were roughly circular to irregular in shape, variable in size, and dark brown with a yellow halo. White to cream-colored, circular, convex, gram-negative bacterial colonies were isolated on nutrient agar and identified as Pseudomonas cichorii based on the LOPAT scheme (2). DNA from four individual colonies inoculated in nutrient broth was extracted using DNeasy columns (Qiagen Inc., Valencia, CA). The PCR-amplified product from four different genes, 16S rRNA (1.5 Kbp), gyrB (0.9 Kbp), rpoB (1.2 Kbp), and rpoD (0.7 Kbp), was sequenced (GenBank Accession Nos. JQ994483, JQ994484, JQ994485, and JQ994486). Nucleotide and translated amino acid sequences for each gene were compared to the nucleotide and protein databases, respectively. The best matches were always with P. cichorii with nucleotide identities ranging from 98 to 99% and amino acid identities from 99 to 100%. Four healthy stevia plants were spray inoculated with 20 ml of a 10⁸ CFU ml^-1 suspension prepared from a 24-hour-old culture, of which two were sprayed with carborundum (silicon carbide) immediately prior to inoculation. Two additional plants were sprayed with carborundum only or sterile tap water only and served as healthy controls. Symptoms began to develop 4 days after inoculation. Spots originated at the tips or edges of the leaves and enlarged over time. Enlarging lesions progressed to encompass the entire leaf, accompanied by water soaking, curling, and necrosis. Blighting typically spread down to the stem and caused dieback. The pathogen was successfully reisolated from the lesions and produced identical LOPAT scheme results. Based on the information collected, it is believed that this is the first confirmed report of bacterial leaf spot caused P. cichorii on stevia worldwide. This find is significant due to the rising popularity of stevia cultivation for its sweetness and medicinal properties (1). To our knowledge, stevia is not currently being grown commercially in Florida; however, there is commercial acreage being developed elsewhere in the United States. References: (1) D. Patil et al. Asian J. Pharm. Clin. Res. 5:1, 2011. (2) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd Edition. The American Phytopathological Society. St. Paul, MN, 2001.

Effect of the heat shock protein HSP27 on androgen receptor expression and function in prostate cancer cells

PURPOSE

Heat shock proteins (HSP) are involved in processes of folding, activation, trafficking and transcriptional activity of most steroid receptors including the androgen receptor (AR). Accumulating evidence links rising heat shock protein 27 (HSP27) levels with the development of castration-resistant prostate cancer. In order to study the functional relationship between HSP27 and the AR, we modulated the expression of the small heat shock protein HSP27 in human prostate cancer (PC) cell lines.

METHODS

HSP27 protein concentrations in LNCaP and PC-3 cells were modulated by over-expression or silencing of HSP27. The effects of HSP27 on AR protein and mRNA levels were monitored by Western blotting and quantitative RT-PCR.

RESULTS

Treatment for the AR-positive LNCaP with HSP27-specific siRNA resulted in a down-regulation of AR levels. This down-regulation of protein was paralleled by a decrease in AR mRNA. Most interestingly, over-expression of HSP27 in PC-3 cells led to a significant increase in AR mRNA although the cells were unable to produce functional AR protein.

CONCLUSION

The observation that HSP27 is involved in the regulation of AR mRNA by a yet unknown mechanism highlights the complexity of HSP27-AR signaling network.

Laurel Wilt, Caused by Raffaelea lauricola, is Confirmed in Miami-Dade County, Center of Florida's Commercial Avocado Production

Laurel wilt, caused by Raffaelea lauricola, threatens native and nonnative species in the Lauraceae in the southeastern United States, including the important commercial crop, avocado, Persea americana (2,4). Although the pathogen's vector, Xyleborus glabratus, was detected in Miami-Dade County, FL in January 2010, laurel wilt had not been reported (4). In February 2011, symptoms of the disease were observed on native swampbay, P. palustris, in Miami-Dade County (25°72'N, 80°48'W). Externally, foliage was brown, necrotic, and did not abscise; internally, sapwood was streaked with dark gray-to-bluish discoloration; and, in dead trees, holes of natal galleries of the vector from which columns of frass were attached were evident. On a semiselective medium for R. lauricola, a fungus with the pathogen's phenotype was isolated from symptomatic sapwood. Colonies were slow growing, light cream in color, with dendritic, closely appressed mycelium and often a slimy surface. A representative strain of the fungus was further identified with PCR primers for diagnostic small subunit (SSU) rDNA (1) and its SSU sequence (100% match, GenBank Accession No. JN578863). In each of two experiments, plants of 'Simmonds' avocado, the most important cultivar in Florida, were inoculated with three strains of the fungus, as described previously (3). Symptoms of laurel wilt developed in all inoculated plants and the fungus was recovered from each. After aerial and further ground surveys, additional symptomatic swampbay trees, some of which had defoliated, were detected in the vicinity of the original site. Since swampbay defoliates only a year or more after symptoms develop (4), the 2010 detection of X. glabratus may have coincided with an undetected presence of the disease. As of July 2011, a 6-km-diameter disease focus was evident in the area, the southernmost edge of which is 5 km from the nearest commercial avocado orchard. In August 2011, a dooryard avocado tree immediately north of the above focus was affected by laurel wilt, and an SSU sequence confirmed the involvement of R. lauricola (GenBank Accession No. JN613280). The outbreak of laurel wilt in Miami-Dade County represents a 150 km southerly jump in the distribution of this disease in the United States ( http://www.fs.fed.us/r8/foresthealth/laurelwilt/dist_map.shtml ) and is the first time this disease has been found in close proximity to Florida's primary commercial avocado production area. Approximately 98% of the state's commercial avocados, worth nearly $54 million per year, are produced in Miami-Dade County. Since effective fungicidal and insecticidal measures have not been developed for large, fruit-bearing trees, mitigation efforts will focus on the rapid identification and destruction of infected trees (3,4). References: (1) T. J. Dreaden et al. Phytopathology 98:S48, 2008. (2) S. W. Fraedrich et al. Plant Dis. 92:215, 2008. (3) R. C. Ploetz et al. Plant Dis. 95:977, 2011. (4) R. C. Ploetz et al. Recovery Plan for Laurel Wilt of Avocado. National Plant Disease Recovery System, USDA, ARS, 2011.

Dampening of blood-flow pulsatility along the carotid siphon: does form follow function?

BACKGROUND AND PURPOSE

The tortuous distal part of the ICA may have an attenuating effect on pulsatile arterial flow. We investigated local arterial blood flow patterns in the ICA proximal and distal to the carotid siphon to detect quantitative waveform changes.

MATERIALS AND METHODS

Arterial flow patterns were analyzed by using flow-sensitized 4D PC MR imaging (time-resolved 3D PCMR) at 3T in 17 healthy volunteers. Time-resolved blood flow velocities were extracted from the source data at the C4 and C7 segments of the ICA. PI, RI, and PA were calculated by using time-resolved flow volume. A linear mixed-effects model was applied to compare values at C4 and C7. Furthermore, 3D blood flow visualization was performed for all 34 ICAs.

RESULTS

PI, RI, and PA were significantly lower at the distal C7 segment compared with the proximal C4 segment of the ICA (P < .0001). Helical flow patterns were observed in 5 ICAs of 4 subjects.

CONCLUSIONS

Arterial flow patterns showed a significant reduction in PI, RI, and PA when compared distal to proximal to the carotid siphon. The observed attenuation of flow pulsatility is most likely related to the contorted shape of the distal ICA and may bear a protective effect for downstream cerebral vasculature.

Enhanced cartilage regeneration in MIA/CD-RAP deficient mice

Melanoma inhibitory activity/cartilage-derived retinoic acid-sensitive protein (MIA/CD-RAP) is a small soluble protein secreted from chondrocytes. It was identified as the prototype of a family of extracellular proteins adopting an SH3 domain-like fold. In order to study the consequences of MIA/CD-RAP deficiency in detail we used mice with a targeted gene disruption of MIA/CD-RAP (MIA−/−) and analyzed cartilage organisation and differentiation in in vivo and in vitro models. Cartilage formation and regeneration was determined in models for osteoarthritis and fracture healing in vivo, in addition to in vitro studies using mesenchymal stem cells of MIA−/− mice. Interestingly, our data suggest enhanced chondrocytic regeneration in the MIA−/− mice, modulated by enhanced proliferation and delayed differentiation. Expression analysis of cartilage tissue derived from MIA−/− mice revealed strong downregulation of nuclear RNA-binding protein 54-kDa (p54^nrb), a recently described modulator of Sox9 activity. In this study, we present p54^nrb as a mediator of MIA/CD-RAP to promote chondrogenesis. Taken together, our data indicate that MIA/CD-RAP is required for differentiation in cartilage potentially by regulating signaling processes during differentiation.

Gallium nitride electrodes for membrane-based electrochemical biosensors

We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50 mHz and 50 kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.

Long-term effects of chondrospheres on cartilage lesions in an autologous chondrocyte implantation model as investigated in the SCID mouse model

Microtraumata often lead to articular cartilage lesions. Due to the bradytrophic character of hyaline cartilage, these lesions are hardly repaired by the organism. Autologous chondrocyte implantation (ACI) was established for restoring isolated structural cartilage defects in knee joints. However, results are not always convincing. Human chondrocytes from patients undergoing total knee arthroplasty were cultured in monolayer followed by condensing single chondrocytes to spheroids (chondrospheres). The integrative capacity of chondrospheres was examined by implanting them into lesions in human articular cartilage specimens and co-implanting them into SCID mice. Mice were sacrificed after 4, 12 and 24 weeks. HE and safranin O staining as well as immunohistochemistry using anti-S100, anti-collagen I and II antibodies were performed and analyzed using semiquantitative scores. Integration of the chondrospheres with the (native) cartilage matrix was analyzed by determining the percentage of adhering surface. With respect to long-term stability, the chondrocytes within chondrospheres showed a typical chondrocytic morphology. Immunohistochemically, a high collagen II production was detected. Over a time period of 24 weeks, an increasing content of collagen type II, glycosaminoglycans and collagenous fibers were found. Importantly, the newly synthesized cartilaginous matrix integrated continuously with the native cartilage lesion border. In conclusion, the presented data demonstrate that chondrospheres are able to restore and conserve their phenotype for at least 24 weeks under in vivo conditions. Moreover, chondrospheres adhere to full-thickness cartilage defects and appear to produce a cartilaginous extracellular matrix which fuses with native cartilage thus generating an autologous cartilage-like repair tissue.

Role of the Netrin System of Repellent Factors on Synovial Fibroblasts in Rheumatoid Arthritis and Osteoarthritis

Changes in the expression of repellent factors, i.e., Netrins and their receptors, may be responsible for the invasive behavior of the synovial tissue cells in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). This study was carried out to analyze the expression of Netrins and their receptors in synovial cells of patients with RA, OA, and control subjects without synovial inflammation. Quantitative RT-PCR was performed to measure the expression of Netrin-1, −3, −4, Neogenin, DCC, UNC5A-D. The influence of Netrin-1 on synovial fibroblasts (SF) was analyzed by determining proliferation, migration, and their ability to organize collagen. SF expressed all repellent factors of the Netrin family. When comparing SF of healthy donors to patients with RA and OA, a stronger expression of UNC5B (4 fold) and UNC5C (769 fold) in RA and OA was found, whereas expression of the other molecules revealed no significant differences. Treating the SF-cells with recombinant Netrin-1 resulted in inhibition of migration of RA- and OA-SFs whereas control cells were not affected. The stronger expression of UNC5B and UNC5C receptors might contribute to the disordered phenotype of RA- and OA-SFs. Addition of Netrin-1 reduces the migratory ability of SFs, potentially by repulsion, as seen in neuronal cells in embryonic development. Due to its function, Netrin-1 may constitute a novel target in the treatment of OA and RA.

[Case report--surgical therapy of a retroperitoneal liposarcoma weighing 45 kg]

Due to the late onset of symptoms, retroperitoneal liposarcoma are often diagnosed in advanced stages when adjacent organs have been infiltrated and the tumours have reached extensive sizes. Surgery remains the first choice of therapy. We report on the primary resection of a 45-kg liposarcoma that was removed en-bloc including the left kidney and descending colon with -tumour-free margins. Nine months later, the follow-up revealed a right-sided recurrence of the tumour, which was surgically removed including the right ureter. Since then, the patient has been without any signs of tumour recurrence or metastases. This report demonstrates that even extreme-ly large tumours can be removed safely and that the size is not a contraindication for primary surgical treatment. Local recurrence is common as seen in our case, and occurs even after R0 resection up to 10 years after the first operation. Recurrences should be surgically removed as this is the only treatment which has been shown to increase survival in even R1 and R2 situations.

[Treatment of lower limb osteomyelitis by a local bone substitute supplemented with antibiotics]

A seriously injured tsunami victim with complicated osteomyelitis is presented. The patient was treated with a new resorbable bone substitute, which can be loaded with different antibiotics. The successful treatment is illustrated by the clinical, radiological and histological features. Bilateral open fractures of the lower leg with open elbow fracture led to a bilateral amputation of the lower legs and the right arm because of a beginning sepsis. The following intramedullary osteitis with multiresistant Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecium was treated with the bone substitute PerOssal combined with systemic and local application of vancomycin and systemic application of ceftazidime and meropenem. This case report illustrates the concept of an additional local antibiotic treatment of osteomyelitis by a bone substitute also functioning as a drug delivery system.

A new method to quantify the effect after subcutaneous injection of lipolytic substances

BACKGROUND

Increasing numbers of patients request lipolytic injection therapy for aesthetic indications. However, only the clinical results of these therapies have been published to date. In most cases, pre- and postprocedure photographs and measurements have been presented. As with every other medical procedure, it is necessary to ensure that the results of lipolytic injections are quantified on an objective and scientific basis with comparable data.

METHODS

In the past, the size of fat tissue could not be measured properly with conventional ultrasound systems. High-resolution, real-time three-dimensional (RT-3D) ultrasound is a fairly new method for measuring the volume of tissue. Therefore, this study aimed to measure the interscapular fat bodies of New Zealand rabbits before and after lipolytic therapy with Lipostabil, phosphatidycholine and orciprenalin (Alupent).

RESULTS

The ultrasound-controlled injection of the lipolytic substances into the interscapular fat body ensured a precise injection. The RT-3D ultrasound data were compared with the magnetic resonance imaging (MRI) measurements performed at the same time. The greatest decrease in volume, up to 44%, was measured with orciprenalin (Alupent). There was a significant correlation between the data from ultrasound imaging and MRI.

CONCLUSION

The data suggest that RT-3D ultrasound imaging could be a simple and fast method for proving the effects on volume size after lipolytic procedures. Of the three investigated substances, orciprenalin (Alupent) showed the highest lipolytic effect in our animal model.

Lower density of synovial nerve fibres positive for calcitonin gene-related peptide relative to substance P in rheumatoid arthritis but not in osteoarthritis

OBJECTIVES

Sensory nerve fibres (NFs) contain two major neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP). The pro-inflammatory role of SP is known, while CGRP has anti-inflammatory activities by inhibiting T helper type 1 cytokines, TNF secretion and leucocyte proliferation. We demonstrated the increase of SP-positive NFs in RA as compared with OA. This study investigated the density of CGRP-positive NFs relative to SP-positive NFs or sympathetic NFs in synovial tissue of patients with RA and OA.

METHODS

By immunofluorescent staining of synovial tissue of 25 patients with RA and 35 patients with OA, NFs positive for CGRP, SP and tyrosine hydroxylase (sympathetic NFs) were quantified.

RESULTS

Density of CGRP-positive NFs was higher in OA than in RA, and density of SP-positive NFs tended to be higher in RA. In RA patients, comparison of CGRP-positive and SP-positive NFs in the same synovial tissue demonstrated less CGRP-positive than SP-positive NFs. The ratio of CGRP-positive NFs to SP-positive NFs was lower in RA as compared with OA. In OA, but not in RA, density of CGRP-positive NFs positively correlated with density of sympathetic NFs, which is much lower in RA patients.

CONCLUSION

The preponderance of SP-positive NFs over CGRP-positive NFs or sympathetic NFs most probably supports the pro-inflammatory process in patients with RA. The reasons for the loss of CGRP in sensory NFs are not known.

Hormone-refractory and metastatic prostate cancer - palliative radiotherapy

Prostate cancer progression is commonly manifested by obstructive uropathy, regional lymphatic metastases and hematogenous metastases to the axial skeleton. Radiotherapy is a mainstay in the palliation of symptomatic metastatic prostate cancer and is most often used for the palliation of painful metastatic bone lesions, resulting in a relief of pain in about 80-90% of patients and a reduction of analgesics. In metastatic disease compromising the integrity of the spinal cord or a nerve root, radiotherapy can be used as an urgent intervention to minimize neurological dysfunction and local progression or as an adjunct to surgical decompression. Local progression is often associated with hematuria, ureteric obstruction and perineal discomfort. Symptoms of metastatic lymphadenopathy like leg edema and back discomfort caused by pelvic or paraaortic metastases are related to the immediate anatomic structures affected. Radiotherapy for localized hormone-refractory prostate cancer has an excellent local control rate; nevertheless, the prognosis is poor, the majority of patients failing with distant metastasis within few years. The role of radiotherapy in hormone-refractory and metastatic prostate cancer, considering the patient's individual situation, are presented and discussed.