Developmental neural activity requires neuron-astrocyte interactions

Developmental neural activity is a common feature of neural circuit assembly. Although glia have established roles in synapse development, the contribution of neuron-glia interactions to developmental activity remains largely unexplored. Here we show that astrocytes are necessary for developmental activity during synaptogenesis in Drosophila. Using wide-field epifluorescence and two-photon imaging, we show that the glia of the central nervous system participate in developmental activity with type-specific patterns of intracellular calcium dynamics. Genetic ablation of astrocytes, but not of cortex or ensheathing glia, leads to severe attenuation of neuronal activity. Similarly, inhibition of neuronal activity results in the loss of astrocyte calcium dynamics. By altering these dynamics, we show that astrocytic calcium cycles can influence neuronal activity but are not necessary per se. Taken together, our results indicate that, in addition to their recognized role in the structural maturation of synapses, astrocytes are also necessary for the function of synapses during development.

A discrete neuronal population coordinates brain-wide developmental activity

In vertebrates, stimulus-independent activity accompanies neural circuit maturation throughout the developing brain^1,2. The recent discovery of similar activity in the developing Drosophila central nervous system suggests that developmental activity is fundamental to the assembly of complex brains³. How such activity is coordinated across disparate brain regions to influence synaptic development at the level of defined cell types is not well understood. Here we show that neurons expressing the cation channel transient receptor potential gamma (Trpγ) relay and pattern developmental activity throughout the Drosophila brain. In trpγ mutants, activity is attenuated globally, and both patterns of activity and synapse structure are altered in a cell-type-specific manner. Less than 2% of the neurons in the brain express Trpγ. These neurons arborize throughout the brain, and silencing or activating them leads to loss or gain of brain-wide activity. Together, these results indicate that this small population of neurons coordinates brain-wide developmental activity. We propose that stereotyped patterns of developmental activity are driven by a discrete, genetically specified network to instruct neural circuit assembly at the level of individual cells and synapses. This work establishes the fly brain as an experimentally tractable system for studying how activity contributes to synapse and circuit formation.

Fibulin Levels in Autosomal Dominant Polycystic Kidney Disease and Its Relationship to Arterial Stiffness

BACKGROUND

The objective of the present study was to evaluate fibulin 1 levels in different stages of patients with autosomal dominant polycystic kidney disease (ADPKD) and investigate possible connections between fibulin-1 and arterial stiffness.

METHODS

For this cross-sectional study, we included 74 patients with ADPKD (mean age, 50.92 ± 15.70 years) and 32 healthy controls (mean age, 49.53 ± 7.32 years). Patients with ADPKD were classified based on CKD epidemiology collaboration (CKD-EPI) equation assessments of estimated glomerular filtration rate (eGFR). Blood levels of fibulin 1 and creatinine levels were analyzed. We measured brachial artery PWV (baPWV), augmentation index (AIx), and pulse pressure (PP) for the assessment of arterial stiffness and systolic and diastolic blood pressures (SBP and DBP, respectively).

RESULTS

Fibulin 1 was significantly higher in the patient group (p < 0.001). SBP, DBP, MAP, PP, and baPWV levels were also significantly higher in the patient group. A statistically significant positive correlation was found between fibulin 1 and creatinine (r = 0.377, p = 0.001). No significant correlation was found between the fibulin 1 levels and age, SBP, DBP, MAP, baPWV, and AIx.

CONCLUSIONS

Plasma concentrations of fibulin 1 increased in patients with ADPKD. Arterial stiffness measured by baPWV increased in patients with ADPKD, but it was not related to fibulin 1 levels.

Cell-type-Specific Patterned Stimulus-Independent Neuronal Activity in the Drosophila Visual System during Synapse Formation

Stereotyped synaptic connections define the neural circuits of the brain. In vertebrates, stimulus-independent activity contributes to neural circuit formation. It is unknown whether this type of activity is a general feature of nervous system development. Here, we report patterned, stimulus-independent neural activity in the Drosophila visual system during synaptogenesis. Using in vivo calcium, voltage, and glutamate imaging, we found that all neurons participate in this spontaneous activity, which is characterized by brain-wide periodic active and silent phases. Glia are active in a complementary pattern. Each of the 15 of over 100 specific neuron types in the fly visual system examined exhibited a unique activity signature. The activity of neurons that are synaptic partners in the adult was highly correlated during development. We propose that this cell-type-specific activity coordinates the development of the functional circuitry of the adult brain.

WH2 and proline-rich domains of WASP-family proteins collaborate to accelerate actin filament elongation

WASP‐family proteins are known to promote assembly of branched actin networks by stimulating the filament‐nucleating activity of the Arp2/3 complex. Here, we show that WASP‐family proteins also function as polymerases that accelerate elongation of uncapped actin filaments. When clustered on a surface, WASP‐family proteins can drive branched actin networks to grow much faster than they could by direct incorporation of soluble monomers. This polymerase activity arises from the coordinated action of two regulatory sequences: (i) a WASP homology 2 (WH2) domain that binds actin, and (ii) a proline‐rich sequence that binds profilin–actin complexes. In the absence of profilin, WH2 domains are sufficient to accelerate filament elongation, but in the presence of profilin, proline‐rich sequences are required to support polymerase activity by (i) bringing polymerization‐competent actin monomers in proximity to growing filament ends, and (ii) promoting shuttling of actin monomers from profilin–actin complexes onto nearby WH2 domains. Unoccupied WH2 domains transiently associate with free filament ends, preventing their growth and dynamically tethering the branched actin network to the WASP‐family proteins that create it. Collaboration between WH2 and proline‐rich sequences thus strikes a balance between filament growth and tethering. Our work expands the number of critical roles that WASP‐family proteins play in the assembly of branched actin networks to at least three: (i) promoting dendritic nucleation; (ii) linking actin networks to membranes; and (iii) accelerating filament elongation.

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Frazzled promotes growth cone attachment at the source of a Netrin gradient in the Drosophila visual system

Axon guidance is proposed to act through a combination of long- and short-range attractive and repulsive cues. The ligand-receptor pair, Netrin (Net) and Frazzled (Fra) (DCC, Deleted in Colorectal Cancer, in vertebrates), is recognized as the prototypical effector of chemoattraction, with roles in both long- and short-range guidance. In the Drosophila visual system, R8 photoreceptor growth cones were shown to require Net-Fra to reach their target, the peak of a Net gradient. Using live imaging, we show, however, that R8 growth cones reach and recognize their target without Net, Fra, or Trim9, a conserved binding partner of Fra, but do not remain attached to it. Thus, despite the graded ligand distribution along the guidance path, Net-Fra is not used for chemoattraction. Based on findings in other systems, we propose that adhesion to substrate-bound Net underlies both long- and short-range Net-Fra-dependent guidance in vivo, thereby eroding the distinction between them.

DOI:http://dx.doi.org/10.7554/eLife.20762.001

The brain of the fruit fly contains hundreds of thousands of neurons, while the human brain contains more than 80 billion. Each of these consists of a cell body that bears an array of branches called dendrites, plus a single cable-like axon. During development, the neurons organize themselves into complex networks by forming connections with one another via their axons and dendrites. But it is not clear exactly how the correct connections form in the correct places.

As they grow out, axons rely on specialized moving structures at their tips – known as growth cones – to probe their environment in search of attractive and repulsive chemical signals released by other cells. When sensors on the surface of growth cones detect a target signal, they initiate processes that cause the growth cone to expand or collapse. This enables the axons to move towards or away from the signal, as appropriate. In all animals studied, proteins called DCC and Netrin form one of the best-known sensor-signal pairs. Growth cones bearing DCC sensors are thought to detect ‘wafting plumes’ or gradients of Netrin and then grow towards the Netrin source.

However, nobody had directly watched neurons respond to Netrin in a living intact animal. Using a type of microscope that can look deep into the developing fly brain, Akin and Zipursky have now followed the movement of growth cones on cells called R8 neurons in fruit fly pupae. Unexpectedly, Akin and Zipursky found that the growth cones of mutant flies that lack Netrin or Frazzled (the fruit fly version of DCC) navigate successfully to their intended destinations. Once there, however, the mutant growth cones were unable to attach to their targets.

Akin and Zipursky’s work is consistent with other observations in a number of animal and insect systems that suggest that Netrin may not attract growth cones via wafting plumes of signal. Instead, Netrin may form a sticky trail that helps growth cones to gain traction as they crawl towards or stick to their destinations. Further experiments are now needed to test whether other neurons in fruit flies and in different animals use Netrin in this way.

DOI:http://dx.doi.org/10.7554/eLife.20762.002

A case report of metastasis of malignant mesothelioma to the retromolar trigone

Background

Malignant mesothelioma is a rare and aggressive tumor with a poor prognosis. Distant metastases are very rare, and the oral cavity metastases are exceedingly rare. Only a few cases with metastasis to oral gingiva are reported. To our knowledge, this is the first case report of pleural mesothelioma metastasized to the retromolar trigone.

Case presentation

A 59-year-old male was referred with a painless growth at retromolar trigone area. It had been present for 2 months and had increased in size during this period of time. Past medical history revealed a malignant mesothelioma. Intraoral examination showed a soft, haemorrhagic, ulcerated lesion at the right retromolar trigone area. There was no destruction of the bony architecture. An incisional biopsy was performed under local anaesthesia. Based on the histopathological and immunohistochemical findings, a final diagnosis of metastatic mesothelioma was made. The patient was informed about the possibility of multiple metastases within the body, but he succumbed after 45 days following deterioration of his medical condition.

Conclusions

Biopsy, history of the patient and clinical picture were provided to the clinicians to make an efficient differential diagnosis. Differential diagnosis must be performed with other oral cancers, because the management is totally different.

Dscam Proteins Direct Dendritic Targeting through Adhesion

Cell recognition molecules are key regulators of neural circuit assembly. The Dscam family of recognition molecules in Drosophila has been shown to regulate interactions between neurons through homophilic repulsion. This is exemplified by Dscam1 and Dscam2, which together repel dendrites of lamina neurons, L1 and L2, in the visual system. By contrast, here we show that Dscam2 directs dendritic targeting of another lamina neuron, L4, through homophilic adhesion. Through live imaging and genetic mosaics to dissect interactions between specific cells, we show that Dscam2 is required in L4 and its target cells for correct dendritic targeting. In a genetic screen, we identified Dscam4 as another regulator of L4 targeting which acts with Dscam2 in the same pathway to regulate this process. This ensures tiling of the lamina neuropil through heterotypic interactions. Thus, different combinations of Dscam proteins act through distinct mechanisms in closely related neurons to pattern neural circuits.

Volume and landmark analysis: comparison of MRI measurements obtained with an endorectal coil and with a phased-array coil

AIM

To compare prostate volumes and distances between anatomical landmarks on MRI images obtained with a phased-array coil (PAC) only and with a PAC and an endorectal coil (ERC).

MATERIALS AND METHODS

Informed consent was waived for this Health Insurance Portability and Accountability Act-compliant study. Fifty-nine men underwent PAC-MRI and ERC-MRI at 1.5 (n = 3) or 3 T (n = 56). On MRI images, two radiologists independently measured prostate volume and distances between the anterior rectal wall (ARW) and symphysis pubis at the level of the verumontanum; ARW and symphysis pubis at the level of the mid-symphysis pubis; and bladder neck and mid-symphysis pubis. Differences between measurements from PAC-MRI and ERC-MRI were assessed with the Wilcoxon RANK SUM test. Inter-reader agreement was assessed using the concordance correlation coefficient (CCC).

RESULTS

Differences in prostate volume between PAC-MRI and ERC-MRI [median: -0.75 mm(3) (p = 0.10) and median: -0.84 mm(3) (p = 0.06) for readers 1 and 2, respectively] were not significant. For readers 1 and 2, median differences between distances were as follows: -10.20 and -12.75 mm, respectively, ARW to symphysis pubis at the level of the verumontanum; -6.60 and -6.08 mm, respectively, ARW to symphysis pubis at the level of the mid-symphysis pubis; -3 and -3 mm respectively, bladder neck to mid-symphysis pubis. All differences in distance were significant for both readers (p ≤ 0.0005). Distances were larger on PAC-MRI (p ≤ 0.0005). Inter-reader agreement regarding prostate volume was almost perfect on PAC-MRI (CCC: 0.99; 95% CI: 0.98-1.00) and ERC-MRI (CCC: 0.99; 95% CI: 0.99-1.00); inter-reader agreement for distance measurements varied (CCCs: 0.54-0.86).

CONCLUSION

Measurements of distances between anatomical landmarks differed significantly between ERC-MRI and PAC-MRI, although prostate volume measurements did not.

Sequential axon-derived signals couple target survival and layer specificity in the Drosophila visual system

Neural circuit formation relies on interactions between axons and cells within the target field. While it is well established that target-derived signals act on axons to regulate circuit assembly, the extent to which axon-derived signals control circuit formation is not known. In the Drosophila visual system, anterograde signals numerically match R1-R6 photoreceptors with their targets by controlling target proliferation and neuronal differentiation. Here we demonstrate that additional axon-derived signals selectively couple target survival with layer specificity. We show that Jelly belly (Jeb) produced by R1-R6 axons interacts with its receptor, anaplastic lymphoma kinase (Alk), on budding dendrites to control survival of L3 neurons, one of three postsynaptic targets. L3 axons then produce Netrin, which regulates the layer-specific targeting of another neuron within the same circuit. We propose that a cascade of axon-derived signals, regulating diverse cellular processes, provides a strategy for coordinating circuit assembly across different regions of the nervous system.

The shape of things to come

Surface receptors can link binding of ligands to changes in the actin-based cell cytoskeleton. Chia et al. and Chen et al. provide evidence for direct binding between the cytoplasmic tails of receptors and the WAVE complex, a regulator of the actin nucleator Arp2/3 complex, which might help to explain how environmental signals are translated into changes in morphology and motility.

Cell-type-specific labeling of synapses in vivo through synaptic tagging with recombination

The study of synaptic specificity and plasticity in the CNS is limited by the inability to efficiently visualize synapses in identified neurons using light microscopy. Here, we describe synaptic tagging with recombination (STaR), a method for labeling endogenous presynaptic and postsynaptic proteins in a cell-type-specific fashion. We modified genomic loci encoding synaptic proteins within bacterial artificial chromosomes such that these proteins, expressed at endogenous levels and with normal spatiotemporal patterns, were labeled in an inducible fashion in specific neurons through targeted expression of site-specific recombinases. Within the Drosophila visual system, the number and distribution of synapses correlate with electron microscopy studies. Using two different recombination systems, presynaptic and postsynaptic specializations of synaptic pairs can be colabeled. STaR also allows synapses within the CNS to be studied in live animals noninvasively. In principle, STaR can be adapted to the mammalian nervous system.

Role of endorectal prostate MRI in patients with initial suspicion of prostate cancer

PURPOSE

To evaluate the role of conventional endorectal prostate MRI in patients with initial suspicion of prostate cancer.

MATERIALS AND METHODS

Ethics board approval was received for this retrospective study of 87 men who underwent 1.5-Tesla conventional prostate MRI with a combination of endorectal and body phased-array coils for suspected prostate cancer before their first systematic 12-core TRUS-guided biopsy. Three radiologists independently analyzed the images, dividing the prostate into 12 regions corresponding to the biopsy scheme and scoring each region for the presence of prostate cancer on a 5-point scale. Results were analyzed by prostate region. ROC analysis was done and descriptive statistics were calculated. The negative predictive value, specificity, sensitivity and positive predictive value were calculated using dichotomized scores (benign tissue = scores of 1 and 2; malignant tissues = scores of 3, 4, and 5).

RESULTS

Biopsy revealed cancer in 47/87 patients (26 low-grade [Gleason score 6]; 21 high-grade [Gleason score ≥ 3 + 4]), and 184/1044 cores (77 low-grade and 107 high-grade) with a median of 3 positive cores per cancer patient (range 1 – 12). The areas under ROC curves were 0.65 – 0.67 for cancer detection by region overall and 0.75 – 0.76 for the detection of high-grade cancer by region. Statistic figures for the detection of all cancers/high-grade cancers by region were as follows: negative predictive value, 87.4 – 88.2 %/92.6 – 93.1 %; specificity, 72.3 – 79.4 %/71.5 – 79.8 %; sensitivity, 49.5 – 54.8 %/62.6 – 69.2 %; and positive predictive value, 29.3 – 34.0 %/29.4 – 34.7 %.

CONCLUSION

In patients with suspected prostate cancer, negative MRI findings indicate the absence of high-grade prostate cancer on subsequent TRUS-guided 12-core biopsy with high probability. However, agreement between conventional 1.5-T endorectal prostate MRI and systematic 12-core TRUS-guided biopsy for the detection of prostate cancer appears to be moderate.

Role of endorectal prostate MRI in patients with initial suspicion of prostate cancer

PURPOSE

To evaluate the role of conventional endorectal prostate MRI in patients with initial suspicion of prostate cancer.

MATERIALS AND METHODS

Ethics board approval was received for this retrospective study of 87 men who underwent 1.5-Tesla conventional prostate MRI with a combination of endorectal and body phased-array coils for suspected prostate cancer before their first systematic 12-core TRUS-guided biopsy. Three radiologists independently analyzed the images, dividing the prostate into 12 regions corresponding to the biopsy scheme and scoring each region for the presence of prostate cancer on a 5-point scale. Results were analyzed by prostate region. ROC analysis was done and descriptive statistics were calculated. The negative predictive value, specificity, sensitivity and positive predictive value were calculated using dichotomized scores (benign tissue = scores of 1 and 2; malignant tissues = scores of 3, 4, and 5).

RESULTS

Biopsy revealed cancer in 47/87 patients (26 low-grade [Gleason score 6]; 21 high-grade [Gleason score ≥ 3 + 4]), and 184/1044 cores (77 low-grade and 107 high-grade) with a median of 3 positive cores per cancer patient (range 1 - 12). The areas under ROC curves were 0.65 - 0.67 for cancer detection by region overall and 0.75 - 0.76 for the detection of high-grade cancer by region. Statistic figures for the detection of all cancers/high-grade cancers by region were as follows: negative predictive value, 87.4 - 88.2 %/92.6 - 93.1 %; specificity, 72.3 - 79.4 %/71.5 - 79.8 %; sensitivity, 49.5 - 54.8 %/62.6 - 69.2 %; and positive predictive value, 29.3 - 34.0 %/29.4 - 34.7 %.

CONCLUSION

In patients with suspected prostate cancer, negative MRI findings indicate the absence of high-grade prostate cancer on subsequent TRUS-guided 12-core biopsy with high probability. However, agreement between conventional 1.5-T endorectal prostate MRI and systematic 12-core TRUS-guided biopsy for the detection of prostate cancer appears to be moderate.

Serum heavy metal and antioxidant element levels of children with recurrent wheezing

STUDY OBJECTIVES

The aim of the study is to investigate the levels of toxic heavy metals related with environmental pollution and trace elements involved in antioxidant system in children suffering from recurrent wheezing.

STUDY DESIGN

One hundred children with recurrent wheezing (at least three recurrences) between the ages from 1 to 6 years took part in the study, and also 116 age- and sex- matched healthy children were involved in the study as a control group. Venous blood samples were collected and serum mercury, lead, aluminium, zinc, selenium, and copper levels were studied using ICP-MS.

RESULTS

Serum lead (0.76±0.15 vs. 0.27±0.01, p:0.001) and mercury levels (1.31±0.15 vs 0.71±0.05, p<0.001) were higher in wheezy group than those acquired from the control group. Serum zinc (69.4±1.65 vs. 78.9±2.78, p:0.005) and selenium (115.6±1.87 vs. 125.4±2.94, p:0.008) levels were lower in wheezy group than those acquired from the control group. Serum zinc levels were found to be correlated with number of ARTIs (r(p):-0.332, p:0.001) and the number of wheezy attacks (r(p):-0.776, p<0.001) during the previous year in the wheezy group.

CONCLUSION

Elevated levels of serum lead and mercury and low levels of zinc and selenium may suggest some disturbances in the antioxidant system in children with recurrent wheezing. This means that children with recurrent wheezing are much more susceptible to environmental pollutants and respiratory tract infections than healthy children and this heavy metal-antioxidant relationship may play a role as a contributing factor in the pathogenesis of recurrent wheezing in children.

In silico reconstitution of actin-based symmetry breaking and motility

Computational modeling and experimentation in a model system for actin-based force generation explain how actin networks initiate and maintain directional movement.

Eukaryotic cells assemble viscoelastic networks of crosslinked actin filaments to control their shape, mechanical properties, and motility. One important class of actin network is nucleated by the Arp2/3 complex and drives both membrane protrusion at the leading edge of motile cells and intracellular motility of pathogens such as Listeria monocytogenes. These networks can be reconstituted in vitro from purified components to drive the motility of spherical micron-sized beads. An Elastic Gel model has been successful in explaining how these networks break symmetry, but how they produce directed motile force has been less clear. We have combined numerical simulations with in vitro experiments to reconstitute the behavior of these motile actin networks in silico using an Accumulative Particle-Spring (APS) model that builds on the Elastic Gel model, and demonstrates simple intuitive mechanisms for both symmetry breaking and sustained motility. The APS model explains observed transitions between smooth and pulsatile motion as well as subtle variations in network architecture caused by differences in geometry and conditions. Our findings also explain sideways symmetry breaking and motility of elongated beads, and show that elastic recoil, though important for symmetry breaking and pulsatile motion, is not necessary for smooth directional motility. The APS model demonstrates how a small number of viscoelastic network parameters and construction rules suffice to recapture the complex behavior of motile actin networks. The fact that the model not only mirrors our in vitro observations, but also makes novel predictions that we confirm by experiment, suggests that the model captures much of the essence of actin-based motility in this system.

Networks of actin filaments provide the force that drives eukaryotic cell movement. In a model system for this kind of force generation, a spherical bead coated with an actin nucleating protein builds and rockets around on an actin “comet tail,” much like the tails observed in some cellular systems. How does a spherically symmetric bead break the symmetry of the actin coat and begin to polymerize actin in a directional manner? A previous theoretical model successfully explained how symmetry breaks, but suggested that the subsequent motion was driven by actin squeezing the bead forwards—a prediction refuted by experiment. To understand how motility occurs, we created a parsimonious computer model that predicted novel experimental behaviors, then performed new experiments inspired by the model and confirmed these predictions. Our model demonstrates how the elastic properties of the actin network explain not only symmetry breaking, but also the details of subsequent motion and how the bead maintains direction.

Ghrelin immunohistochemistry of gastric adenocarcinoma and mucoepidermoid carcinoma of salivary gland

Ghrelin (G-HH) synthesized in several tissues including salivary and stomach glands stimulates appetite in humans by modulating neuropeptide Y neurons in the hypothalamic arcuate nucleus. Loss of appetite is one of the most important symptoms of stomach cancer. We conducted a study using immunohistochemistry to determine whether salivary glands and stomach cancer tissues produce ghrelin. We determined that negative ghrelin immunohistochemistry discriminates tumors from normal tissues and may therefore further our understanding of the clinically important problem of reduced food intake and anorexia in cancer patients. Radioimmunoassay analyses confirmed that cancer cells do not produce a G-HH peptide, whereas normal cells yield this peptide.

The role of positron emission tomography/computed tomography in the diagnosis of pleural diseases

BACKGROUND

The aim of the study was to assess the role of F-18 fluoro-2-D-deoxyglucose positron emission tomography ( (18)FDG-PET)/computed tomography (CT) in patients with undiagnosed pleural diseases and to compare the findings with those of invasive diagnostic procedures.

METHODS

The study included 83 patients with pleural lesions (63 with pleural effusion; 20 with pleural thickening) on CT scan performed between November 2005 and December 2007. The study group consisted of 63 males and 20 females; their median age was 47 years. PET-CT scan was performed for all patients before surgery. A maximum standard uptake value greater than 3.0 was accepted as positive for malignancy. For histopathological diagnosis, video-assisted thoracoscopic surgery was performed in 76 patients and a mini-thoracotomy was performed for the remaining 7 patients.

RESULTS

Postoperative histopathological examination revealed malignancy in 44 cases, 25 of which were malignant mesothelioma; the remaining 39 cases were benign. There were no false negative results, but two false positive results (tuberculosis). PET-CT scanning had 100 % sensitivity, 94.8 % specificity and 97.5 % accuracy.

CONCLUSION

Our study suggests that PET-CT may be an effective tool for the differentiation of benign and malignant pleural diseases. We believe that PET/CT may prevent redundant surgical procedures in young patients who are SUVmax negative.

Capping protein increases the rate of actin-based motility by promoting filament nucleation by the Arp2/3 complex

Capping protein (CP) is an integral component of Arp2/3-nucleated actin networks that drive amoeboid motility. Increasing the concentration of capping protein, which caps barbed ends of actin filaments and prevents elongation, increases the rate of actin-based motility in vivo and in vitro. We studied the synergy between CP and Arp2/3 using an in vitro actin-based motility system reconstituted from purified proteins. We find that capping protein increases the rate of motility by promoting more frequent filament nucleation by the Arp2/3 complex and not by increasing the rate of filament elongation as previously suggested. One consequence of this coupling between capping and nucleation is that, while the rate of motility depends strongly on the concentration of CP and Arp2/3, the net rate of actin assembly is insensitive to changes in either factor. By reorganizing their architecture, dendritic actin networks harness the same assembly kinetics to drive different rates of motility.

Effects of Cholerella sp. microalgae extract on colonic anastomosis in rats with protein-energy malnutrition

OBJECTIVE

Algae, which are used as supplementary nutrients in various countries, are products rich in protein, vitamins and minerals. The aim of this study was to investigate the effects of algae extracts on the healing of colonic anastomosis in malnourished rats.

METHOD

Seventy-two rats were randomized to three groups. Group 1 was fed with standard diet for 15 days, before and after the colonic anastomosis. Groups 2 and 3 were fed with a malnutrition diet for 15 days prior to colonic anastomosis and then with the basic diet for 15 days there after. Group 3 also received an extract of algae derived from Cholerella sp. via oral gavage postoperatively, in addition to the basic diet. Rats were killed on the 3rd, 7th and 15th postoperative day. Blood samples were collected to evaluate prealbumin, transferring and albumin levels. Anastomotic bursting pressures (BPs), histopathology and tissue hydroxyproline levels were evaluated after killing.

RESULTS

In group 3, the prealbumin level on the 3rd postoperative day and transferrin and albumin levels on the 7th and 15th postoperative days were significantly increased compared with the other groups (P < 0.05). Tissue hydroxyproline levels and anastomotic BPs of group 3 were significantly higher than in group 2 on the 3rd, 7th and 15th postoperative days (P < 0.05). Histopathological examination of the anastomosis revealed significantly better healing patterns for group 3 than for groups 1 and 2 (P < 0.05).

CONCLUSION

Extract derived from Cholerella sp. microalgae has favourable effects on healing of experimental colon anastomoses.

Prostate cancer imaging

As prostate cancer is a biologically heterogeneous disease for which a variety of treatment options are available, the major objective of prostate cancer imaging is to achieve more precise disease characterization. Magnetic resonance imaging (MRI) may enhance the staging of prostate cancer compared with clinical evaluation, transrectal ultrasound, or computed tomography (CT), and allows concurrent evaluation of prostatic, periprostatic, and pelvic anatomy. In clinical practice, the fusion of MRI or dynamic contrast-enhanced MRI (DCE-MRI) with MR spectroscopic imaging (MRSI) is improving the evaluation of cancer location, size, and extent, while providing an indication of tumor aggressiveness. Pretreatment knowledge of these prognostic variables is essential for achieving minimally invasive, patient-specific therapy.

Painless burn injury caused by post-traumatic syringomyelia

BACKGROUND

Syringomyelia, which is generally related to congenital malformations and tumors, may lead to paresthesia and dysfunctions in thermo-algesic perception. Post-traumatic syringomyelia (PTS) is a rare type of this disease characterised by the development of a cystic formation containing cerebrospinal fluid (CSF), which develops inside the spinal cord after spinal trauma.

AIM

The description of a case diagnosed as painless burn injury caused by PTS.

METHOD

One case report.

CONCLUSION

Although there are a number of reports regarding the formation of neuropathic ulcers related to syringomyelia, painless burn injury descriptions are very rare. Despite available limited data related to this subject, it is important to warn patients about traumas-especially burns-after a diagnosis of PTS.

Metronidazole 0.75% gel vs. ketoconazole 2% cream in the treatment of facial seborrheic dermatitis: a randomized, double-blind study

BACKGROUND

Recently, two placebo-controlled studies have shown that topical metronidazole was effective in the treatment of seborrheic dermatitis.

OBJECTIVE

To compare the efficacy and safety of metronidazole 0.75% gel with that of ketoconazole 2% cream in the treatment of facial seborrheic dermatitis.

METHODS

A total of 60 consecutive patients with facial seborrheic dermatitis were included. Patients were randomized into two groups. One group used ketoconazole 2% cream with metronidazole gel as vehicle; the other group used metronidazole 0.75% gel with ketoconazole cream as vehicle for a 4-week treatment period. Main outcome measures were change in clinical severity scores, patients' and investigator's global evaluation of improvement and frequency of side-effects.

RESULTS

All the assessments were made by an investigator who was unaware of which group the patients were allocated to. Mean percentage decrease in clinical severity scores from baseline to last available visit was 63.4% (95% CI 57.7-69) and 54.4% (95% CI 47.9-61) in the ketoconazole- and metronidazole-treated patients, respectively (P = 0.31). Eighty-two per cent of patients in the ketoconazole group vs. 79% of patients in the metronidazole group rated their global improvement as significant or moderate (P > 0.05). No statistically significant difference in the frequency of side-effects was detected between the two groups. The results of this study need to be confirmed in further studies involving large numbers of patients.

CONCLUSION

Our data demonstrated that metronidazole 0.75% gel had a comparable efficacy and safety profile with that of ketoconazole 2% cream in the treatment of facial seborrheic dermatitis.

Evaluation of bone turnover in postmenopausal patients with type 2 diabetes mellitus using biochemical markers and bone mineral density measurements

Although osteoporosis is reported as a potential complication of type 1 diabetes mellitus (DM), the effects of type 2 DM on bone mass are conflicting. Most of the studies conducted in recent years reveal that bone mineral density (BMD) values of type 2 DM patients are not decreased and even increased when compared with healthy control groups. In this study we evaluated bone turnover in 57 postmenopausal type 2 DM patients utilizing biochemical markers for bone formation and resorption, and BMD measurements. We found that BMD values in diabetic patients (0.91 +/- 0.11 g/cm(2) for lumbar region, 0.89 +/- 0.14 g/cm(2) for hip region) were higher than healthy postmenopausal control group (0.81 +/- 0.12 g/cm(2) for lumbar region, 0.76 +/- 0.10 g/cm(2) for hip region). Serum alkaline phosphatase values were similar to the control group, whereas serum osteocalcin and N-telopeptide/creatinine (NTx/Cr) values were significantly lower than the control group (osteocalcin: 8.82 +/- 4.03 ng/ml, NTx/Cr: 122.70 +/- 81.76 nMBCE/mMCr) in diabetic patients (osteocalcin: 4.44 +/- 3.53 ng/ml, NTx/Cr: 42.24 +/- 29.97 nMBCE/mMCr). Also a significant correlation was observed between body mass index and BMD values. Our findings suggested that the bone turnover rate is remarkably lower in type 2 DM patients compared to healthy postmenopausal patients.

Hepatic alveolar echinococcosis. A case report

Alveolar echinococcosis is a rare parasitic disease caused by Echinococcus multilocularis and most commonly involves the liver. Early diagnosis and precise evaluation of the localisation and the extent of the lesions are essential for treatment. In this report, we present US and CT findings in a patient with hepatic alveolar echinococcosis.

Erectile dysfunction in premature ejaculation

Between October 1993 and December 1995, 45 patients with premature ejaculation were included in this study. The patients were divided into two groups etiologically, as having primary or secondary ejaculation. After a complete laboratory evaluation all patients underwent papaverine tests color Doppler ultrasonography pharmacocavernosometry-cavernosography and consequently organic etiology were investigated. Venous leakage was found in 5 (22,7%), arterial or mix insufficiency in 2 (9%) of the patients with primary premature ejaculation. In secondary premature ejaculation group, venous leakage was encountered in 9 patients (39,1%), arterial insufficiency in 2 patients (8,6%). In conclusion, investigation of organic etiology for the patients with premature ejaculation, particularly with secondary premature ejaculation, seems to be beneficial for correct diagnosis.

A case of growing teratoma syndrome

Residual masses are a common finding after chemotherapy for metastases from nonseminomatous germ cell tumours of the testes. The prognosis of these patients with resected teratoma following successful cisplatin-based combination chemotherapy generally has been assumed to be good. Herein we reported an unusual teratoma case named "growing teratoma syndrome' by Logothetis et al. This patient was treated with multiple operations.