Target fishing reveals PfPYK-1 and PfRab6 as potential targets of an antiplasmodial 4-anilino-2-trichloromethylquinazoline hit compound.

We present investigations about the mechanism of action of a previously reported 4-anilino-2-trichloromethylquinazoline antiplasmodial hit-compound (Hit A), which did not share a common mechanism of action with established commercial antimalarials and presented a stage-specific effect on the erythrocytic cycle of P. falciparum at 8 < t < 16 h. The target of Hit A was searched by immobilising the molecule on a solid support via a linker and performing affinity chromatography on a plasmodial lysate. Several anchoring positions of the linker (6,7 and 3') and PEG-type linkers were assessed, to obtain a linked-hit molecule displaying in vitro antiplasmodial activity similar to that of unmodified Hit A. This allowed us to identify the PfPYK-1 kinase and the PfRab6 GTP-ase as potential targets of Hit A.

Estimated or Measured GFR in Living Kidney Donors Work-up?

The value of estimated glomerular filtration rate (eGFR) in living kidney donors screening is unclear. A recently published web-based application derived from large cohorts, but not living donors, calculates the probability of a measured GFR (mGFR) lower than a determined threshold. Our objectives were to validate the clinical utility of this tool in a cohort of living donors and to test two other strategies based on chronic kidney disease epidemiology collaboration (CKD-EPI) and on MDRD-eGFR. GFR was measured using 51 Cr- ethylene-diamine tetraacetic acid urinary clearance in 311 potential living kidney donors (178 women, mean age 50 ± 11.6 years). The web-based tool was used to predict those with mGFR < 80 mL/min/1.73 m2 . Inputs to the application were sex, age, ethnicity, and plasma creatinine. In our cohort, a web-based probability of mGFR <90 mL/min/1.73 m2 higher than 2% had 100% sensitivity for detection of actual mGFR <80 mL/min/1.73 m2 . The positive predictive value was 0.19. A CKD-EPI-eGFR threshold of 104 mL/min/1.73 m2 and an MDRD-eGFR threshold of 100 mL/min/1.73 m2 had 100% sensitivity to detect donors with actual mGFR <80 mL/min/1.73 m2 . We obtained similar results in an external cohort of 354 living donors. We confirm the usefulness of the web-based application to identify potential donors who should benefit from GFR measurement.

Intracranial involvement by multiple myeloma.

Intracranial involvement is a rare complication of multiple myeloma. It results either from direct extra-osseous spread from adjacent skeletal plasmacytomas or extra-medullary disease via haematogenous dissemination. The imaging appearances are non-specific, and dural, leptomeningeal, and parenchymal involvement can all occur. The purpose of this review is to illustrate the various neuroimaging appearances of this rare entity, focusing on MRI.

Arachnoid Membranes: Crawling Back into Radiologic Consciousness.

The arachnoid membranes are projections of connective tissue in the subarachnoid space that connect the arachnoid mater to the pia mater. These are underappreciated and largely unrecognized by most neuroradiologists despite being found to be increasingly important in the pathogenesis, imaging, and treatment of communicating hydrocephalus. This review aims to provide neuroradiologists with an overview of the history, embryology, histology, anatomy, and normal imaging appearance of these membranes, as well as some examples of their clinical importance.

Non-Contrast-Enhancing Tumor: A New Frontier in Glioblastoma Research.

There is a growing understanding of the prognostic importance of non-contrast-enhancing tumor in glioblastoma, and recent attempts at more aggressive management of this component using neurosurgical resection and radiosurgery have been shown to prolong survival. Optimizing these therapeutic strategies requires an understanding of the features that can distinguish non-contrast-enhancing tumor from other processes, in particular vasogenic edema; however, the limited and heterogeneous manner in which it has been defined in the literature limits clinical translation. This review covers pertinent literature on our growing understanding of non-contrast-enhancing tumor and focuses on key conventional MR imaging features for improving its delineation. Such features include subtle differences in the degree of FLAIR hyperintensity, gray matter involvement, and focal mass effect. Improved delineation of tumor from edema will facilitate more aggressive management of this component and potentially realize associated survival benefits.

PACS Integration of Semiautomated Imaging Software Improves Day-to-Day MS Disease Activity Detection.

BACKGROUND AND PURPOSE: The standard for evaluating interval radiologic activity in MS, side-by-side MR imaging comparison, is restricted by its time-consuming nature and limited sensitivity. VisTarsier, a semiautomated software for comparing volumetric FLAIR sequences, has shown better disease-activity detection than conventional comparison in retrospective studies. Our objective was to determine whether implementing this software in day-to-day practice would show similar efficacy. MATERIALS AND METHODS: VisTarsier created an additional coregistered image series for reporting a color-coded disease-activity change map for every new MS MR imaging brain study that contained volumetric FLAIR sequences. All other MS studies, including those generated during software-maintenance periods, were interpreted with side-by-side comparison only. The number of new lesions reported with software assistance was compared with those observed with traditional assessment in a generalized linear mixed model. Questionnaires were sent to participating radiologists to evaluate the perceived day-to-day impact of the software. RESULTS: Nine hundred six study pairs from 538 patients during 2 years were included. The semiautomated software was used in 841 study pairs, while the remaining 65 used conventional comparison only. Twenty percent of software-aided studies reported having new lesions versus 9% with standard comparison only. The use of this software was associated with an odds ratio of 4.15 for detection of new or enlarging lesions (P = .040), and 86.9% of respondents from the survey found that the software saved at least 2-5 minutes per scan report. CONCLUSIONS: VisTarsier can be implemented in real-world clinical settings with good acceptance and preservation of accuracy demonstrated in a retrospective environment.

MRI Features Can Predict 1p/19q Status in Intracranial Gliomas.

BACKGROUND AND PURPOSE: The 2016 revision of the World Health Organization Classification of Tumors of the Central Nervous System mandates codeletion of chromosomes 1p and 19q for the diagnosis of oligodendroglioma. We studied whether conventional MR imaging features could predict 1p/19q status. MATERIALS AND METHODS: Patients with previous 1p/19q testing were identified through pathology department records, typically performed on the basis of an oligodendroglial component on routine histology; 69 patients met the inclusion criteria. Preoperative imaging of patients with grade II or III gliomas was retrospectively assessed by 2 neuroradiologists, blinded to the 1p/19q status. Thirteen MR imaging features were first assessed in a small initial cohort (n = 10), after which the criteria were narrowed for the remaining patients as a validation cohort. RESULTS: There was 85% agreement between radiologists for the overall prediction of 1p/19q status in the validation cohort, with an accuracy of 84%. The presence of >50% T2-FLAIR mismatch and calcification was found to be the most useful for predicting 1p/19q status. The >50% T2-FLAIR mismatch variable was demonstrated in 14 tumors and had 100% specificity for identifying a noncodeleted tumor (P = .001), with 97% interobserver correlation. Calcification was visualized in 7 tumors, 6 of which were 1p/19q codeleted (specificity, 97%; P = .006), with 100% interobserver correlation. CONCLUSIONS: The presence of >50% T2-FLAIR mismatch is highly predictive of a noncodeleted tumor, while calcifications suggest a 1p/19q codeleted tumor. If formal 1p/19q testing is not possible, a combined MR imaging-histologic assessment may improve the diagnostic accuracy over histology alone.

Neuroradiologists Compared with Non-Neuroradiologists in the Detection of New Multiple Sclerosis Plaques.

BACKGROUND AND PURPOSE: Multiple sclerosis monitoring is based on the detection of new lesions on brain MR imaging. Outside of study populations, MS imaging studies are reported by radiologists with varying expertise. The aim of this study was to investigate the accuracy of MS reporting performed by neuroradiologists (someone who had spent at least 1 year in neuroradiology subspecialty training) versus non-neuroradiologists. MATERIALS AND METHODS: Patients with ≥2 MS studies with 3T MR imaging that included a volumetric T2 FLAIR sequence performed between 2009 and 2011 inclusive were recruited into this study. The reports for these studies were analyzed for lesions detected, which were categorized as either progressed or stable. The results from a previous study using a semiautomated assistive software for lesion detection were used as the reference standard. RESULTS: There were 5 neuroradiologists and 5 non-neuroradiologists who reported all studies. In total, 159 comparison pairs (ie, 318 studies) met the selection criteria. Of these, 96 (60.4%) were reported by a neuroradiologist. Neuroradiologists had higher sensitivity (82% versus 42%), higher negative predictive value (89% versus 64%), and lower false-negative rate (18% versus 58%) compared with non-neuroradiologists. Both groups had a 100% positive predictive value. CONCLUSIONS: Neuroradiologists detect more new lesions than non-neuroradiologists in reading MR imaging for follow-up of MS. Assistive software that aids in the identification of new lesions has a beneficial effect for both neuroradiologists and non-neuroradiologists, though the effect is more profound in the non-neuroradiologist group.

Global fit concept in revision hip arthroplasty for cementless press-fit femoral stems.

A revision stem may be required after a femoral extended trochanteric osteotomy (ETO) is made during revision hip arthroplasty. The two main complications of straight cementless femoral stems are subsidence due to inadequate osteointegration and stress-shielding. We will describe an original revision method with ETO that uses a straight cementless stem. The goal of this method was to achieve the most extensive press-fit possible during stem implantation to improve the transmission of stresses to the bone and to prevent reduction in bone density. The intramedullary preparation was done after closure and fixation of the ETO, which allows impaction of the revision stem with metaphyseal and diaphyseal press-fit. We report encouraging results with preservation of periprosthetic bone stock and good osteointegration of these revision stems at the final follow-up. Pronounced sagittal curvature or large bone defects are contraindications for this technique.

Distinguishing Neuroimaging Features in Patients Presenting with Visual Hallucinations.

Visual hallucinations are relatively uncommon presentations in medical and psychiatric clinics, where they are generally regarded as a marker of possible underlying "organic" brain disease. Thus, patients with visual hallucinations are often referred for imaging of the brain. This article presents a pragmatic approach for the radiologist reviewing such imaging. Because conditions that can present with visual hallucinations are legion, a familiarity with the features of the hallucinations themselves, which can serve as clues to the underlying cause, can be helpful in interpreting such cases. We consider the nature of visual hallucinations and the mechanisms underlying their formation. We then provide a framework to guide the search for their cause, first in terms of focal lesions along the visual pathway and then global conditions affecting >1 region.

Affinity labelling of human transcortin.

The binding site of transcortin has been studied by using bromoacetyltestosterone and bromoacetylated derivatives of progesterone which were monohydroxylated at different positions of the steroid nucleus. Specificity of affinity labelling was demonstrated by the displad cortisol analog was added to a [3H]cortisol-transcortin complex solution. The binding site crevice was found to be very narrow in the vicinity of the A and B rings of steroid since 2alpha-hydroxyprogesterone, 6alpha- or 6beta-bromoacetoxyprogesterone and dexamethasone could not displace bound cortisol. A specific affinity labelling was obtained with 11alpha-bromoacetoxyprogesterone, 16alpha-bromoacetoxyprogesterone and 17beta-bromoacetyltestosterone. The results of the affinity labelling by these hormone analogs suggested that one methionine and one histidine residues were located within the active site:methionine might interact with the 11beta-hydroxyl group and histidine with the 20 keto group of cortisol.

Reversible dissociation of cortisol-transcortin complex by sodium para-chloromercuribenzoate.

Mercurials are considered as sulphydryl group specific reagents and one of them, sodium para-chloromercuribenzoate (PCMB), is currently used for SH titration. It has been shown that cellular steroid receptors are reversibly inactivated by mercurials even when the binding site is occupied by the steroid (Coty, W.A. (1980) J. Biol. Chem. 255, 8035-8037). This is a striking difference with alkylating SH reagents such as iodoacetic acid or N-ethylmaleimide, since these reagents inactivate only steroid-free receptors. In order to explain this discrepancy, we tested, in the present study, the specificity of PCMB on a blood plasma steroid binding protein: human transcortin. This protein presents the advantage, over cellular receptors, of being well characterized and to be available in a pure state. The transcortin-cortisol complex was also reversibly inactivated by PCMB when the reaction was carried out at a high excess of reagent over protein; such conditions are those previously used with steroid receptors. The reversibility was obtained not only with a reducing agent (dithiothreitol) but also with EDTA, which suggests a poor stability of the protein mercurial bond and therefore a nonspecific action. The decrease of activity was the result of a loss of binding sites and Scatchard plot analysis did not reveal any detectable decrease of the affinity constant for cortisol. Transcortin possesses two SH groups per molecule, one of these being buried in native conformation. After blockage of the accessible SH group by aminoethylation, transcortin kept the same activity, but when this aminoethylated transcortin was incubated with PCMB a loss of activity was obtained, although the residual buried SH group was again titrable with Ellman's reagent. Therefore, we can conclude that the action of PCMB on proteins must be interpreted with precaution, since it can induce an inactivation that is SH-independent.

Immunohistochemical detection of cells positive for colony-stimulating factor 1 in lymph nodes from reactive lymphadenitis, and Hodgkin's disease.

Colony-stimulating factor 1 (CSF-1) is a cytokine involved in hematopoiesis and perhaps more importantly in the early stages of immunological defense mechanisms. Although numerous studies of in vitro CSF-1-producing cells have been published, in vivo data is totally lacking. According, we performed immunohistochemical detection of CSF-1-positive cells on frozen sections of reactive lymphadenitis (three cases) and Hodgkin's disease (13 cases) lymph node biopsies, using as antibody a highly specific polyclonal rabbit antiserum prepared in our laboratory. Endothelial cells from high endothelial venules and most fibroblasts were positive in all cases (reactive lymphadenitis and Hodgkin's samples), and most lymphocytes in interfollicular T cell areas showed faint granular positivity in reactive lymphadenitis lymph nodes. Hodgkin and Reed-Sternberg cells were positive in all cases tested, although staining intensity was highly variable and the percentage of positive cells differed from case to case. These data from in vivo biopsies confirm previous results for in vitro CSF-1 production by endothelial cells, fibroblasts, T lymphocytes, and Hodgkin cell lines. They are consistent with the role of this cytokine in immune response and raise the question of its significance in Hodgkin's disease.

Expression and function of tap in the gustatory and olfactory organs of Drosophila.

We have recently described the identification of a gene, tap, which encodes a bHLH protein expressed in one neuron of each larval chemosensory organ. Here we show that tap is expressed at a late stage in the development of one type of adult chemosensory organ, the gustatory bristles of the leg, wing and proboscis. We also show that tap is expressed very early in the development of a second type of chemosensory receptors, the olfactory organs of the antenna. The results of behavioral experiments suggest that the ectopic expression of tap affects the response to sugar and salt.

MRI grading versus histology: predicting survival of World Health Organization grade II-IV astrocytomas.

BACKGROUND AND PURPOSE: Histologic grading of intracranial astrocytomas is affected by sampling error and substantial inter- and intraobserver variability. We proposed that incorporating MR imaging into grading will predict patient survival more accurately than histopathology alone. MATERIALS AND METHODS: Patients with a new diagnosis of World Health Organization grades II-IV astrocytoma or mixed oligoastrocytoma diagnosed between September 2007 and December 2010 were identified. Two hundred forty-five patients met the inclusion criteria. Preoperative MRIs were independently reviewed by 2 readers blinded to the histologic grade, and an MR imaging grade was given. The MR imaging and histopathologic grades were compared with patient survival. RESULTS: Patients with grade II or III astrocytomas on histology but evidence of necrosis on MR imaging (consistent with a grade IV tumor) had significantly worse survival than patients with the same histology but no evidence of necrosis on MR imaging (P = .002 for grade II histology and P = .029 for grade III). Their survival was not significantly different from that in patients with grade IV tumors on histology (P = .164 and P = .385, respectively); this outcome suggests that all or most are likely to have truly been grade IV tumors. MR imaging evidence of necrosis was less frequent in grade II and III oligoastrocytomas, preventing adequate subgroup analysis. CONCLUSIONS: MR imaging can improve grading of intracranial astrocytomas by identifying patients suspected of being undergraded by histology, with high interobserver agreement. This finding has the potential to optimize patient management, for example, by encouraging more aggressive treatment earlier in the patient's course.

Improving Multiple Sclerosis Plaque Detection Using a Semiautomated Assistive Approach.

BACKGROUND AND PURPOSE: Treating MS with disease-modifying drugs relies on accurate MR imaging follow-up to determine the treatment effect. We aimed to develop and validate a semiautomated software platform to facilitate detection of new lesions and improved lesions. MATERIALS AND METHODS: We developed VisTarsier to assist manual comparison of volumetric FLAIR sequences by using interstudy registration, resectioning, and color-map overlays that highlight new lesions and improved lesions. Using the software, 2 neuroradiologists retrospectively assessed MR imaging MS comparison study pairs acquired between 2009 and 2011 (161 comparison study pairs met the study inclusion criteria). Lesion detection and reading times were recorded. We tested inter- and intraobserver agreement and comparison with original clinical reports. Feedback was obtained from referring neurologists to assess the potential clinical impact. RESULTS: More comparison study pairs with new lesions (reader 1, n = 60; reader 2, n = 62) and improved lesions (reader 1, n = 28; reader 2, n = 39) were recorded by using the software compared with original radiology reports (new lesions, n = 20; improved lesions, n = 5); the difference reached statistical significance (P < .001). Interobserver lesion number agreement was substantial (≥1 new lesion: κ = 0.87; 95% CI, 0.79-0.95; ≥1 improved lesion: κ = 0.72; 95% CI, 0.59-0.85), and overall interobserver lesion number correlation was good (Spearman ρ: new lesion = 0.910, improved lesion = 0.774). Intraobserver agreement was very good (new lesion: κ = 1.0, improved lesion: κ = 0.94; 95% CI, 0.82-1.00). Mean reporting times were <3 minutes. Neurologists indicated retrospective management alterations in 79% of comparative study pairs with newly detected lesion changes. CONCLUSIONS: Using software that highlights changes between study pairs can improve lesion detection. Neurologist feedback indicated a likely impact on management.

Studies of human transcortin at different pHs: circular dichroism, polymerisation and binding affinity.

The transcortin we have used in this work is extremely pure. This was shown by the polymerisation observed at pH 4. This polymerisation is never observed with an impure form of transcortin [4]. Moreover, since it is known that the presence of cortisol in the binding site is an essential condition to the activity of purified transcortin [5], it appears that a correlation between the secondary structure and the biological activity of the transcortin exists. The results we have obtained are summarized below: (1) The inhibition of the transcortin binding capacity essentially takes place between pH 5 and 4. (2) A reorganisation of the structure of the protein moiety is observed between pH 6.5 and 5.9. (3) A decrease of the helicity ratio is observed between pH 5 and 4. It appears therefore that, in the limits of experimental accuracy of CD measurements to determine the amount of beta-structure, no appreciable change of binding activity is taking place after the appearance of a large percentage of beta-structure between pH 6.5 and 6. On the other hand, the sudden decrease of protein activity at low pH is likely to be correlated with the disappearance of a well-defined helical region. Other biochemical and physical experiments would be of course necessary, in order to precise this first observation of a structure-function relationship in transcortin.

[Characterization and physico-chemical properties of human transcortin]. / Caractérisation et propriétés physico-chimiques de la transcortine humaine

The molecular weight of human transcortin, calculated from the sedimentation coefficient, was found to be 49,500, thus slightly lower than previously reported values. After purification, human transcortin trended to polymerize rapidly, with participation of both non covalent bonds and one disulfide bridge per dimer. The physicochemical parameters, the amino-acid and carbohydrate composition were determined; its stability was studied under different conditions. Preliminary structural studies showed that the N-terminal sequence of the polypeptide chain was: Met-Asp-Pro-Asn-Ala-Ala-Tyr-Val and that the C-terminal amino acid was leucine.

Involvement of tyrosine kinase activity in the low-density lipoprotein receptor expression in human lung adenocarcinoma cell line A549.

In common with other tumour cell lines but in contrast to normal cells, the human adenocarcinoma cell line A549 showed a biphasic regulation of the LDL receptor activity during growth both LDL binding and metabolism (sum of internalised and degraded LDL) increased during the log exponential growth phase and decreased when the cells approached confluence. This period of increasing LDL receptor activity coincided with a high resistance to cholesterol down-regulation which suggested a sterol-independent pathway of stimulation. Since A549 cells have an autocrine loop of growth factors, two of which have tyrosine kinase activity, the LDL receptor activity was tested in the presence of the tyrosine kinase inhibitor, genistein. When cells were incubated in the absence of cholesterol (LPDS medium), the inhibition that occurred was two-fold higher during the exponential growth phase than during the confluent phase. Moreover, the residual LDL binding and metabolism after genistein inhibition were completely resistant to down-regulation by cholesterol only during the growth phase. When cholesterol was present (FCS medium). inhibition was observed only during the growth phase. The inhibition of LDL receptor activity by genistein was found to be the result of a loss in the number of LDL binding sites, while the dissociation constant was not affected. This loss was accompanied by a disappearance of mRNA as shown by RNase mapping. By comparison, LDL receptor activity of normal cells (fibroblasts) was also affected by genistein during the exponential growth phase but was much more cholesterol-dependent. Taken together, these results suggest that the tyrosine kinase pathway is essential to up-regulate LDL receptor expression in highly dividing cells and particularly in tumour cells in which the sterol regulation is deficient.