bluuebunny/crossref_metadata_2025 huggingface dataset:
Transparent Film Dressing vs Pressure Dressing After Percutaneous Transluminal Coronary Angiography
Authors: McIe Stacie , Petitte Trisha , Pride Lori , Leeper Donna , Ostrow C. Lynne
Published: February 2009

Background Pressure dressings have been used as the standard following sheath removal after percutaneous transluminal angioplasty in many institutions. Patients complain about discomfort while the dressing is in place, pain when the dressing is removed after discharge, and skin complications afterward. Many patients have experienced skin irritation where tape has been applied. Nurses have also described difficulty assessing the sheath insertion site in the groin when a pressure dressing is in place.

Objectives To compare 3 different dressings with respect to effect on bleeding, discomfort voiced by patients, and ease of groin assessment in patients after percutaneous transluminal coronary angiography.

Methods A total of 100 patients were randomly assigned to 1 of 3 groups: pressure dressing, transparent film dressing, or adhesive bandage. Outcome variables were bleeding, patient discomfort, and nurse-reported ease of observation of the groin site.

Results No bleeding occurred in patients with transparent film dressings or adhesive bandages. Patients rated these dressings significantly higher than they rated the pressure dressing. Because two-thirds of the sample had previously undergone percutaneous transluminal coronary angiography, they could compare their experience with the new dressing with previous experiences with pressure dressings. Nurses rated the ease of assessing the groin significantly higher for the transparent film and adhesive bandage dressings than for pressure dressings.

Conclusions As a result of this study, a practice change was made hospital-wide: rather than a standard opaque pressure dressing, a transparent film dressing is used for all patients after removal of a femoral sheath.
Silicone Foley's catheter: A useful splint in ear surgeries
Authors: Karanth Siddharth K. , Mokal Nitin J.
Published: February 2009

Maintenance of ear projection and post auricular sulcus in staged ear reconstruction in microtia is a trying problem. So also is the maintenance of the patency of the external auditory meatus following recanalization and meatoplasty. Numerous splints and dressing techniques have been described for the above situations. Some of the problems encountered include the availability of the materials, cost, expertise in fabrication and compliance. Aims: To devise a simple, reliable, inexpensive and readily available splint for the maintenance of post auricular sulcus and external auditory meatus opening. Settings and Design: A silicone catheter is made out of a soft and inert material that doesn't cause tissue necrosis or any loss of skin graft. The basic design is that of a simple, selfretaining type of splint that doesn't dislodge and can be prepared within minutes on the operating table. Materials and Methods: This splint has been used in four cases of microtia reconstruction and one case of congenital external auditory meatus stenosis between June 2006 and August 2007. A 14 or 16 Fr silicone Foley's catheter was used. The proximal end of a catheter of required length was retained and the distal part was cut off. The catheter was looped into a circle around the base of the reconstructed ear and secured in position with a suture. A similar construct was used in cases of external auditory meatus reconstruction or recanalization. The funnel-shaped distal drainage end was sutured to the circular frame near the region of the tragus. This funnel was inserted into the external auditory canal. Results: The catheter was found to sit snugly in the newly created sulcus, thereby maintaining the sulcus and ear projection. It aided in maintaining the meatal opening of a satisfactory diameter in the case of external auditory canal recanalization. It was never found to slip or get dislodged in any of the cases. There was no skin graft loss or tissue necrosis due to the use of the splint. Conclusions: The silicone Foley's catheter is found to be a simple, readily available, inexpensive and reliable self-retaining splint following ear elevation in microtia and external auditory meatus recanalization. The catheter is easily constructed and applied intraoperatively. The results following its usage have been uniformly good in all cases without causing any adverse events at the operated site or discomfort to the patient ensuring good compliance.
Radial, renal and craniofacial anomalies: Baller-Gerold syndrome
Authors: Murthy Jyotsna , Babu Ramesh , Ramanan Padmasani Venkat
Published: February 2009

The Baller-Gerold syndrome is a rare syndrome with very few cases published in literature. Craniosynostosis and radial aplasia are striking features, easy to diagnose. However, there are many differential diagnoses. Often, the question raised is whether the Baller-Gerald syndrome is a distinct entity. We report a patient with findings of craniosynostosis and radial aplasia consistent with the diagnosis of the Baller-Gerold syndrome. Genotypic heterogeneity could possibly underlie the phenotypic variability exhibited by these cases.
Choroidal melanoma: B-scan spectrum
Authors: Aironi V. D. , Chougule S. R. , Singh Jitendra
Published: February 2009

Malignant melanoma of the choroid is the commonest primary intra-ocular tumor in the adults, 85% arising from the choroid and 15% from the ciliary body. We present two cases of intraocular choroidal melanoma with varied manifestations. One in a fifty two year old man and another in a forty-two years old woman presenting with gradual loss of vision in one eye. A bilobed mushroom shaped (figure of eight shape) intraocular lesion was seen to arise from choroid protruding into the vitreous and revealing a "waist " in it′s midportion in the right eye of fifty two year old man. B-Scan of right eye in the forty-two years old woman revealed a large intraocular mass with mid level echos and lobulated contours filling nearly the whole posterior segment.
The role of combining MR cholangiopancreatography and T1W imaging in detecting common bile duct micro-stones
Authors: Xindao Yin , Liping Wang , Lingquan Lu , Taisheng Zhang , Qianzhi Wu , Jianping Gu
Published: February 2009

Objective: To assess the role of adding T1W images to MR cholangiopancreatography (MRCP) in detecting common bile duct (CBD) micro-stones. Subjects and Methods: From January 2005 to December 2006, a total of 104 patients with CBD stones were preoperatively studied by routine MRI and MRCP. Micro-stones, measuring less than 5 mm, were proven at surgery or ERCP following the MRI scans, within one to five days in 56/104 patients. Routine MRI scans included RF-FAST axial T1W images (TR/TE 155 ms/3.4 ms) and EXPRESS axial T2W (15000 ms/81 ms) as well as coronal T2W (15000 ms/81 ms) images. Features of CBD micro-calculi on T1W and MRCP images and the sensitivities of T1W images and MRCP for the diagnosis of CBD micro-stones were analyzed. Results: Among these 56 patients, gallbladder stones coexisted with choledocholithiasis in 30 patients and 7 patients had a past history of cholecystectomy for gallstones. The signal intensities of CBD micro-calculi on T1W images were high, relative to the low signal intensity of the bile in 47 patients. Filling defects on MRCP images were shown in 33 patients. Both T1W images alone and a combination of MRCP with T1W images had a higher sensitivity in detecting CBD micro-calculi than MRCP alone. Statistical analysis showed significant differences between the combination of MRCP with T1W images and MRCP alone in the ability to detect micro-stones (Fisher′s exact test, P < 0.01). Conclusion: For MRCP, adding a T1W sequence is helpful in increasing the sensitivity for diagnosing micro-calculi of the common bile ducts.
Case report: Mounier-Kuhn syndrome
Authors: Kachhawa Satish , Meena M , Jindal Gaurav , Jain Bharat
Published: February 2009

Tracheobronchomegaly or Mounier-Kuhn syndrome is a rare disorder characterized by marked dilatation of the trachea and main bronchi, bronchiectasis, and recurrent respiratory tract infections. The etiology of this disorder is uncertain and the clinical presentation is variable. The diagnosis is usually made on the basis of the characteristic CT scan findings. We report a case in a 21-year-old man presenting with recurrent lower respiratory tract infections.
Clinical applications of functional MRI in epilepsy
Authors: Kesavadas Chandrasekharan , Thomas Bejoy
Published: February 2009

The role of functional MRI (fMRI) in the presurgical evaluation of patients with intractable epilepsy is being increasingly recognized. Real-time fMRI is an easily performable diagnostic technique in the clinical setting. It has become a noninvasive alternative to intraoperative cortical stimulation and the Wada test for eloquent cortex mapping and language lateralization, respectively. Its role in predicting postsurgical memory outcome and in localizing the ictal activity is being recognized. This review article describes the biophysical basis of blood-oxygen-level-dependent (BOLD) fMRI and the methodology adopted, including the design, paradigms, the fMRI setup, and data analysis. Illustrative cases have been discussed, wherein the fMRI results influenced the seizure team′s decisions with regard to diagnosis and therapy. Finally, the special issues involved in fMRI of epilepsy patients and the various challenges of clinical fMRI are detailed.
Case report: Retroperitoneal biliary fluid collections secondary to common bile duct rupture - an unusual complication of choledocholithiasis in a child
Authors: Rastogi Rajul , Rastogi Vaibhav
Published: February 2009

Rupture of the common bile duct (CBD) in a child secondary to choledocholithiasis is a rare event. In this article, the authors describe a child who presented with an acute abdomen due to CBD rupture, with subsequent acute retroperitoneal fluid collections, all diagnosed preoperatively on CT scan. The aim of this article is to show the pathways that such collections can take in the retroperitoneum.
Case report: Cholangiocarcinoma in a choledochal cyst
Authors: Chaturvedi Arti , Singh JP , Rastogi Vikas
Published: February 2009

Cholangiocarcinoma is a dreaded complication of unresected choledochal cysts, with an incidence approaching 20-30% in early adulthood. The risk of cholangiocarcinoma remains high where an internal drainage procedure has been performed and the cyst has been partially resected or left unresected. We report a case of cholangiocarcinoma occurring in an unresected choledochal cyst following a drainage procedure in infancy and highlight the role of PET/CT in its diagnosis.
Interventional radiology in the management of portal hypertension
Authors: Punamiya Sundeep J
Published: February 2009

From being a mere (though important) diagnostic tool, radiology has evolved to become an integral part of therapy in portal hypertension today. Various procedures are currently available, the choice depending on the etiology and location of disease, the pathoanatomy, and the symptomatology. The main aim of any procedure is to reduce the portal pressure by either direct or indirect methods. This can be achieved with transjugular intrahepatic portosystemic shunt (TIPS), recanalization of the hepatic vein outflow, recanalization of the portal vein and its tributaries, recanalization of dysfunctional portosystemic shunts, partial splenic embolization, and embolization of arterioportal shunts. When any of these procedures cannot be performed due to anatomical or physiological reasons, the symptoms can often be controlled effectively with embolization of varices or balloon-occluded retrograde transvenous obliteration of varices (BRTO). This article briefly describes the procedures, their results, and their current status in the treatment of portal hypertension.
Storage media for computers in radiology
Authors: Dandu Ravi Varma
Published: February 2009

The introduction and wide acceptance of digital technology in medical imaging has resulted in an exponential increase in the amount of data produced by the radiology department. There is an insatiable need for storage space to archive this ever-growing volume of image data. Healthcare facilities should plan the type and size of the storage media that they needed, based not just on the volume of data but also on considerations such as the speed and ease of access, redundancy, security, costs, as well as the longevity of the archival technology. This article reviews the various digital storage media and compares their merits and demerits.
Prenatal diagnosis of fetal syndromes
Authors: Rama Murthy BS
Published: February 2009

A syndrome is a pattern of multiple anomalies arising due to a single known causative factor. Ultrasonography has enabled us to recognize many fetal anomalies and dysmorphic features. Recognition of the anomaly pattern leads to the diagnosis of a particular syndrome. This enables us to counsel prospective parents and aids in management. We present a selection of fetal syndromes in the form of a pictorial essay.
Role of cervical ultrasonography in primary hyperparathyroidism
Authors: Shaheen Feroze , Chowdry Nisar , Gojwari Tariq , Wani Arshad Iqbal , Khan Showkat
Published: February 2009

Aim: To evaluate the role of USG in the preoperative localization of parathyroid adenomas in patients with symptomatic hyperparathyroidism and to compare its usefulness with that of scintigraphy scan and postoperative findings.
Material and methods : Twenty-five patients with symptomatic primary hyperparathyroidism were subjected to USG of the neck and nuclear scintigraphy, followed by surgery. The results were independently analyzed and compared with per-operative findings.
Results : The 25 patients had a total of 28 abnormal glands: 22 solitary adenomas, and 6 multiple adenomas (two each in three patients). USG detected 20 out of 22 solitary adenomas and three out of six multiple adenomas. USG missed five abnormal glands, two of which were in the neck and three in the mediastinum. Scintigraphy was positive in 26 abnormal glands, out of which 22 were single and four were multiple. Two abnormal glands were missed: one in the neck and one in the mediastinum.
Conclusion: As limited neck dissection for primary hyperparathyroidism becomes increasingly popular, USG has been found to be a sensitive, specific, and easily available noninvasive investigation for parathyroid localization. It can be easily offered to patients as a method for preoperative localization prior to limited parathyroid surgery outside tertiary care settings.
Case Report: Spontaneous aneurysm of ductus arteriosus: A rare cause of hoarseness of voice in adults
Authors: Gothi Rajesh , Ghonge Nitin P
Published: February 2009

Ortner′s syndrome (left recurrent laryngeal nerve palsy caused by cardiovascular pathology) is described in literature as occurring secondary to a variety of conditions. Spontaneous aneurysm of ductus arteriosus is a rare cause of this condition. We present a case where an adult patient with an aneurysm of the ductus arteriosus presented for the first time at the age of 62 years with hoarseness of voice secondary to left recurrent laryngeal nerve palsy.
Image-guided lumbar facet joint infiltration in nonradicular low back pain
Authors: Chaturvedi Arti , Chaturvedi Sunil , Sivasankar Rajiv
Published: February 2009

Objective: To assess the efficacy of facet joint infiltrations for pain relief in 44 selected patients with chronic nonradicular low back pain (LBP). Materials and Methods: Forty-four patients with chronic LBP of more than 3 months′ duration were selected for facet joint infiltration. The majority (n = 24) had facetal pain with no evidence of significant facetal arthropathy on imaging. Fifteen patients had radiological evidence of facetal arthropathy, one had a facet joint synovial cyst, three were post-lumbar surgery patients, and two patients had spondylolysis. Facet joint injections were carried out under fluoroscopic guidance in 39 patients and under CT guidance in 5 cases. Pain relief was assessed using the visual analog scale at 1 h post-procedure and, thereafter, at 1, 4, 12, and 24 weeks. Results: A total of 141 facet joints were infiltrated in 44 patients over a 2-year period. There was significant pain relief in 81.8% patients 1 h after the procedure, in 86.3% after 1 week, in 93.3% after 4 weeks, in 85.7% after 12 weeks, and in 62.5% after 24 weeks. No major complications were encountered. Conclusions: Facet nerve block was found to be a simple, minimally invasive, and safe procedure. With meticulous patient selection, we achieved long-term success rates of over 60%. We conclude that this method represents an important alternative treatment for nonradicular back pain.
Three-dimensional imaging for hepatobiliary and pancreatic diseases: Emphasis on clinical utility
Authors: Kim Soo Jin , Choi Byung Ihn , Kim Se Hyung , Lee Jae Young
Published: February 2009

Three-dimensional (3D) imaging allows disease processes and anatomy to be better understood, both by radiologists as well as physicians and surgeons. 3D imaging can be performed with USG, CT scan and MRI, using different modes or rendering that include surface-shaded display, volume-based rendering, multiplanar imaging, etc. All these techniques are used variably depending on the indications.
Monitor displays in radiology: Part 1
Authors: Indrajit IK , Verma B
Published: February 2009

Monitor displays are an integral part of today′s radiology work environment, attached to workstations, USG, CT/MRI consoles and PACS terminals. For each modality and method of use, the correct display monitor needs to be deployed. It helps to have a basic understanding of how monitors work and what are the issues involved in their selection.
Pictorial essay: Coronary artery variants and anomalies
Authors: Rahalkar Anand M. , Rahalkar Mukund D.
Published: February 2009

CT coronary angiography has helped radiologists understand the variations and anomalies of the anatomy of the coronary arteries and, thus, to alert the cardiologist whenever such an anomaly is present. This can be of immense help to the clinician planning interventional procedures such as stenting, balloon dilatation, or graft surgery, particularly when there are secondary changes of calcification, plaque formation and stenosis.
Fetal diastematomyelia: MR imaging: A case report
Authors: Kulkarni Makarand , Ruparel Mitosh , Redkar Rajeev
Published: February 2009

MRI is increasingly being used in the diagnosis of fetal anomalies suspected on USG. The USG evaluation of fetal spinal anomalies is limited by acoustic shadowing, fetal position and the amount of liquor. Fetal MRI is able to show spinal anomalies well, as in our case of fetal diastematomyelia with a dorsal dermal sinus, suspected on USG at 28 weeks gestation.
Schnelle Synthese von Benzofluorenen durch selenvermittelte Carbocyclisierungen
Authors: Shahzad Sohail A. , Wirth Thomas
Published: February 2009

Ein Ring ist nicht genug: Eine neuartige doppelte Cyclisierung führt ausgehend von Stilbenen über Dihydronaphthaline zu Benzo[b]fluorenen. Der entscheidende Schritt ist eine durch Selenelektrophile in Gegenwart von Lewis‐Säuren vermittelte intramolekulare Knüpfung von C‐C‐Bindungen.

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Zeolitic Boron Imidazolate Frameworks
Authors: Zhang Jian , Wu Tao , Zhou Cong , Chen Shumei , Feng Pingyun , Bu Xianhui
Published: February 2009

B‐hive? A family of crystalline materials analogous to porous AlPO4 but based on boron imidazolate frameworks (BIFs) can be formed by the crosslinking of various presynthesized boron imidazolates with monovalent cations (Li+ and Cu+, see picture). This synthetic method is capable of generating a large variety of open frameworks, ranging from the four‐connected zeolitic sodalite type to the three‐connected chiral (10,3)‐a type.

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Fast Synthesis of Benzofluorenes by Selenium‐Mediated Carbocyclizations
Authors: Shahzad Sohail A. , Wirth Thomas
Published: February 2009

When one ring is not enough: A new double cyclization of stilbene derivatives results in benzo[b]fluorenes via dihydronaphthalenes. The presence of a selenium electrophile and a Lewis acid are crucial for the formation of the CC bonds.

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Total Synthesis of Sporolide B
Authors: Nicolaou K. C. , Tang Yefeng , Wang Jianhua
Published: February 2009

An ocean of discovery: The first total synthesis of the highly oxygenated, marine‐derived, natural product sporolide B has been achieved through a convergent strategy. The key steps involve a ruthenium‐catalyzed [2+2+2] cycloaddition to assemble the indene structural motif and a thermally induced Diels–Alder‐type reaction to forge the macrocycle (see scheme).

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VESGEN 2D: Automated, User‐Interactive Software for Quantification and Mapping of Angiogenic and Lymphangiogenic Trees and Networks
Authors: Vickerman Mary B. , Keith Patricia A. , McKay Terri L. , Gedeon Dan J. , Watanabe Michiko , Montano Monica , Karunamuni Ganga , Kaiser Peter K. , Sears Jonathan E. , Ebrahem Quteba , Ribita Daniela , Hylton Alan G. , Parsons‐Wingerter Patricia
Published: February 2009

Pseudocolor view of vascular branching generations in the chorioallantoic membrane (CAM) of quail. Vascular architecture was analyzed using the automated, user‐interactive software, VESsel GENeration Analysis (VESGEN). See Vickerman, et al., on page 320, in this issue.
Comparative study of corn stover pretreated by dilute acid and cellulose solvent‐based lignocellulose fractionation: Enzymatic hydrolysis, supramolecular structure, and substrate accessibility
Authors: Zhu Zhiguang , Sathitsuksanoh Noppadon , Vinzant Todd , Schell Daniel J. , McMillan James D. , Zhang Y.‐H. Percival
Published: February 2009

Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.3 mg cellulase per gram of glucan], glucan digestibilities of the corn stover pretreated by DA and COSLIF were 84% at hour 72 and 97% at hour 24, respectively. At a low cellulase loading (5 FPUs per gram of glucan), digestibility remained as high as 93% at hour 24 for the COSLIF‐pretreated corn stover but reached only ∼60% for the DA‐pretreated biomass. Quantitative determinations of total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non‐cellulose accessibility to cellulase (NCAC) based on adsorption of a non‐hydrolytic recombinant protein TGC were measured for the first time. The COSLIF‐pretreated corn stover had a CAC of 11.57 m2/g, nearly twice that of the DA‐pretreated biomass (5.89 m2/g). These results, along with scanning electron microscopy images showing dramatic structural differences between the DA‐ and COSLIF‐pretreated samples, suggest that COSLIF treatment disrupts microfibrillar structures within biomass while DA treatment mainly removes hemicellulose. Under the tested conditions COSLIF treatment breaks down lignocellulose structure more extensively than DA treatment, producing a more enzymatically reactive material with a higher CAC accompanied by faster hydrolysis rates and higher enzymatic digestibility. Biotechnol. Bioeng. 2009;103: 715–724. © 2009 Wiley Periodicals, Inc.
Influence of uncertainties in pH, pMg, activity coefficients, metabolite concentrations, and other factors on the analysis of the thermodynamic feasibility of metabolic pathways
Authors: Vojinović Vojislav , von Stockar Urs
Published: February 2009

Thermodynamic feasibility analysis (TFA) has been used as a tool capable of providing additional constraints to the mass balance‐based methods of analysis of metabolic networks (e.g., flux balance analysis). Several publications have recently appeared in which TFA of different metabolic pathways from relatively simple to the genome‐scale networks was described as a means of detecting the possible metabolic control steps. However, in order to perform TFA, many simplifying assumptions were necessary. On the other hand, it has been shown by applying TFA to the well‐known pathway of glycolysis that erroneous simplifying assumptions may seriously bias the results of the analysis. A quantitative analysis of the influence of non‐ideality of the biochemical system, pH, temperature, and complexation of the metabolites with Mg2+ ions as well as a number of other factors on the TFA is reported. It is shown that the feasibility of glycolysis is very seriously limited by the reaction of oxidative phosphorylation of glyceraldehyde phosphate, and that the intracellular concentration of the main product of this reaction, biphosphoglycerate, must be anywhere from 10 to 100 times lower than published values. In addition, the driving force for this reaction, and consequently the feasibility of the entire pathway depend strongly on the intracellular pH and ionic strength and to a lesser extent on pMg and temperature. The analysis may also be influenced by uncertainties of the dissociation and magnesium complexation constants of glyceraldehyde phosphate. The analysis demonstrates the crucial importance of taking such factors into account when performing TFA. It also suggests an urgent need for experimental determinations of such factors as a prerequisite for sensible thermodynamic analysis of metabolism on a genome‐wide scale. Biotechnol. Bioeng. 2009;103: 780–795. © 2009 Wiley Periodicals, Inc.
Behavioral and neurological foundations for the moral and legal implications of intoxication, addictive behaviors and disinhibition
Authors: Leeman Robert F. , Grant Jon E. , Potenza Marc N.
Published: February 2009

Disinhibition and addictive behaviors are related and carry moral implications. Both typically involve diminished consideration of negative consequences, which may result in harm to oneself or others. Disinhibition may occur on state and trait levels, and addictive substances may elicit disinhibitory states, particularly when intoxication is reached. Data suggest that trait disinhibition and addictions may be conceptualized as involving misdirected motivation with underlying biological bases including genetic factors, alterations in neurotransmitter systems and differences in regional brain function. The influences of intoxication on the brain share similarities with cognitive impairments in individuals with chronic substance abuse and those with trait disinhibition related to frontal lobe injuries. These findings raise questions about volitional impairment and morality. Although impaired volition related to disinhibition and addictive behaviors has been studied from multiple perspectives, additional research is needed to further characterize mechanisms of impairment. Such findings may have important implications in multiple legal and psychiatric domains. Copyright © 2009 John Wiley & Sons, Ltd.
Dispersed Phantom Scatterer Technique Reveals Subtle Differences in Substrate Recognition by Phospholipase D Inactive Mutants
Authors: Morasso Carlo , Bellini Tommaso , Monti Daniela , Bassi Mattia , Prosperi Davide , Riva Sergio
Published: February 2009

Stretch out: An elastic light‐scattering‐based method that makes use of phantom nanoparticles as a substrate organizer (see illustration) allowed the quantitative evaluation of the molecular recognition events between a series of inactivated mutants of phospholipase D and lysophosphatidylcholine. The results highlight the remarkable effects on binding capability caused by single amino acid substitutions.

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DNA and RNA‐Controlled Switching of Protein Kinase Activity
Authors: Röglin Lars , Altenbrunn Frank , Seitz Oliver
Published: February 2009

Constrained: The readily programmable nucleic acid mediated recognition is used to constrain a phosphopeptide that was flanked by PNA segments. RNA‐based switching allows control over the activity of target enzymes such as the protein kinase Src. It might thus be feasible to transduce changes of the concentration of selected RNA molecules to changes of the activity of signal transduction proteins.

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Protein switches use the binding energy gained upon recognition of ligands to modulate the conformation and binding properties of protein segments. We explored whether the programmable nucleic acid mediated recognition might be used to design or mimic constraints that limit the conformational freedom of peptide segments. The aim was to design nucleic acid–peptide conjugates in which the peptide portion of the conjugate would change the affinity for a protein target upon hybridization. This approach was used to control the affinity of a PNA–phosphopeptide conjugate for the signal transduction protein Src kinase, which binds the cognate phosphopeptides in a linear conformation. Peptide–nucleic acid arms were attached to known peptide binders. The chimeric molecules were studied in three modes: 1) as single strands, 2) constrained by intermolecular hybridization (duplex formation) and 3) constrained by intramolecular hybridization (hairpin formation). Of note, duplexes that were designed to accommodate bulged peptide structures (for example, in hairpins or bulges) had lower binding affinities than duplexes in which the peptide was allowed to adopt a more relaxed conformation. Greater than 90‐fold differences in binding affinities were observed. It was, thus, feasible to make use of DNA hybridization to reversibly switch from no to almost complete inhibition of Src‐SH2–peptide binding, and vice versa. A series of DNA and PNA‐based hybridization experiments revealed the importance of charges and conformational effects. Nucleic acid mediated switching was extended to the use of RNA; this enabled a regulation of the enzymatic activity of the Src kinase. The proof‐of‐principle results demonstrate for the first time that PNA–peptide chimeras can transduce changes of the concentration of a given RNA molecule to changes of the activity of a signal transduction enzyme.
Cover Picture: Screening for Cytochrome P450 Reactivity by Harnessing Catalase as Reporter Enzyme (ChemBioChem 4/2009)
Authors: Rabe Kersten S. , Spengler Mark , Erkelenz Michael , Müller Joachim , Gandubert Valerie J. , Hayen Heiko , Niemeyer Christof M.
Published: February 2009

The cover picture shows a bacterial cytochrome P450 enzyme (CYP152A1, blue protein) screening for new substrates, such as nifidepine (highlighted green). The identification of novel reactivities of P450 enzymes is of major importance for applications in biocatalysis, biosensing and metabolic engineering. In their contribution on p. 751 ff, Niemeyer et al. report a novel assay for the rapid and facile screening of substrate libraries for organic hydroperoxide‐mediated P450 reactivity. Peroxide depletion is monitored in a fluorescence microplate assay, by harnessing a previously undescribed reactivity of the enzyme catalase (orange protein structure). The assay thus connects the occurrence of P450 reactivity with a universal read‐out, thereby circumventing the need for substrate‐specific detection schemes.

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Exponential data fitting using multilinear algebra: the decimative case
Authors: Papy Jean‐Michel , De Lathauwer Lieven , Van Huffel Sabine
Published: February 2009

This paper presents a high‐precision method for the estimation of the parameters of a signal, modelled as a finite sum of complex damped exponentials, whose poles may be close. It is well known that increasing the sampling rate increases the accuracy of traditional methods, like total least squares (TLSs)‐ESPRIT and HTLS, in the case of closely spaced exponentials. However, in the case of long sequences, the computational complexity makes these methods hard to apply. To overcome this problem, the HTLSDstack and the HTLSDsum methods make use of decimated sequences. In this paper, we propose a higher order counterpart of HTLSDstack, based on concepts from multilinear algebra. Basically, it consists of decimating an oversampled signal by a factorD, making sure that no aliasing occurs. Each sequence is arranged in a Hankel matrix and theDHankel matrices are stacked in a third‐order tensor. A dimensionality reduction algorithm is applied to the tensor and the resulting subspace is used to retrieve the parameters of interest. The dimensionality reduction is possibly unsymmetric in the different modes of the tensor, which allows us to take into account ill conditioning when poles are close. The new method yields better results than HTLSDstack while its complexity stays fairly low compared to non‐decimative methods. Copyright © 2009 John Wiley & Sons, Ltd.
Nonlinear regression checking via local polynomial smoothing with applications to thermogravimetric analysis
Authors: Cao Ricardo , Naya Salvador
Published: February 2009

A goodness‐of‐fit test statistic for nonlinear regression models based on local polynomial estimation is proposed in this paper. The criterion used to construct the test is the distance between the parametric fit and the nonparametric regression estimation. The good performance of the test is shown via a simulation study. The method is applied to check a logistic mixture regression model for real data coming from a thermal analysis problem. Copyright © 2009 John Wiley & Sons, Ltd.
Some surprising properties of multivariate curve resolution‐alternating least squares (MCR‐ALS) algorithms
Authors: Rajkó Róbert
Published: February 2009

In this paper, some surprising properties are discussed related to multivariate curve resolution‐alternating least squares (MCR‐ALS) algorithms. The analytical solution of the feasible regions opens the door to follow the convergence tracks of MCR algorithms on Borgen plot at least in case of three‐component systems. Using Borgen plot, a hitherto unknown discrepancy of MCR‐ALS algorithms has been revealed, i.e. the sub‐ and even the final solutions can be outside of the range of the data matrix R. A new constraint, i.e. ‘zero orthogonal part for the estimated profiles’ for MCR‐ALS algorithms is suggested to speed up the convergence. If the minimal constraint, i.e. nonnegativity, can be only used, then the band solution should be preferred. This recommendation is strengthened by simulated investigations. However if the practical problem is simple enough, i.e. the concentration profiles are well‐separated, and/or there are no minor components, and/or the spectra are different enough, and/or there is zero range in either for concentration or spectral profiles, and/or all necessary further constraints are known and applied etc., then MCR‐ALS algorithms can work properly. Copyright © 2009 John Wiley & Sons, Ltd.
Total Syntheses of Amphidinolides B1, B4, G1, H1 and Structure Revision of Amphidinolide H2
Authors: Fürstner Alois , Bouchez Laure C. , Morency Louis , Funel Jaques‐Alexis , Liepins Vilnis , Porée François‐Hugues , Gilmour Ryan , Laurich Daniel , Beaufils Florent , Tamiya Minoru
Published: February 2009

Nature is a pretty unselective “chemist”when it comes to making the highly cytotoxic amphidinolide macrolides of the B/G/H series. To date, 16 different such compounds have been isolated, all of which could now be approached by a highly convergent and largely catalysis‐based route (see figure). This notion is exemplified by the total synthesis of five prototype members of this family.

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Dinoflagellates of the genusAmphidiniumproduce a “library” of closely related secondary metabolites of mixed polyketide origin, which are extremely scarce but highly promising owing to the exceptional cytotoxicity against various cancer cell lines. Because of the dense array of sensitive functionalities on their largely conserved macrocyclic frame, however, these amphidinolides of the B, D, G and H types elapsed many previous attempts at their synthesis. Described herein is a robust, convergent and hence general blueprint which allowed not only to conquest five prototype members of these series, but also holds the promise of making “non‐natural” analogues available by diverted total synthesis. This notion transpires for a synthesis‐driven structure revision of amphidinolide H2. The successful route hinges upon a highly productive Stille–Migita cross‐coupling reaction at the congested and chemically labile 1,3‐diene site present in all such targets, which required the development of a modified chloride‐ and fluoride‐free protocol. The macrocyclic ring could be formed with high efficiency and selectivity by ring‐closing metathesis (RCM) engaging a vinyl epoxide unit as one of the reaction partners. Because of the sensitivity of the targets to oxidizing and reducing conditions as well as to pH changes, the proper adjustment of the protecting group pattern for the peripheral ‐OH functions also constitutes a critical aspect, which has to converge to silyl groups only once the diene is in place. Tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) turned out to be a sufficiently mild fluoride source to allow for the final deprotection without damaging the precious macrolides.
Molecular Editing and Biological Evaluation of Amphidinolide X and Y
Authors: Fürstner Alois , Kattnig Egmont , Kelter Gerhard , Fiebig Heinz‐Herbert
Published: February 2009

Scarce and precious: A collection of compounds with deep‐seated structural “point mutations” within the framework of the marine natural products amphidinolide X and Y was prepared by “diverted total synthesis”. The resulting products provided first insights into the cytotoxicity profile of these extremely scarce macrolides.

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Deliberate deviations from the previously described total syntheses of amphidinolide X (1) and Y (2) allowed a collection of seven designed analogues of these extremely scarce marine natural products to be obtained. These fully synthetic “natural product‐like” compounds enabled first insights into the previously unknown structure–activity relationships governing this series. Although the average cytotoxicity is moderate, it was found that certain bladder, colon and prostate cancer cell lines are fairly sensitive, and that the best synthetic analogues are more active than the natural products themselves. The syntheses rely on the 9‐MeO‐9‐BBN variant of the Suzuki coupling for the formation of the carbon frameworks, as well as on Yamaguchi lactonization reactions for the cyclization of the macrocyclic rings.
Highly Enantioselective Synthesis of β‐Aminophosphinates with Two Stereogenic Atoms and Their Conversion into Optically Pure Ethyl β‐Amino‐H‐phosphinates
Authors: Zhang Dehui , Yuan Chengye
Published: February 2009

β‐Amino acid analogues: The nucleophilic addition of ethyl (diethoxyethyl)methylphosphinate to a variety of (S)‐(tert‐butanesulfinyl)imines leads to the isolation of two enantioenriched β‐aminophosphinates (>95 % ee; see scheme). Subsequent removal of the protecting groups through pivotal metal‐catalyzed thiophenolysis leads to optically pure ethyl β‐amino‐H‐phosphinates.

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The first highly stereoselective synthesis of β‐aminophosphinates has been realized by the nucleophilic attack of an anion generated from ethyl (1,1‐diethoxyethyl)methylphosphinate and nBuLi on (S)‐N‐(tert‐butanesulfinyl)imines at −78 °C. Subsequent removal of the protecting groups through pivotal metal‐catalyzed thiophenolysis leads to optically pure ethyl β‐amino‐H‐phosphinates. During this process, a pair of diastereoisomers with different configurations on the phosphorus atom can be obtained. Until now, Ellman N‐(tert‐butanesulfinyl)imines have demonstrated excellent chirality‐induced activity in the syntheses of both α‐aminophosphinates and β‐aminophosphinates. On the other hand, the Cram rules have been successfully applied to rationalize the highly enantioselective formation of (RC)‐α‐aminophosphinates and (RC)‐β‐aminophosphinates, whereas the phenomenon that the two pairs of diastereoisomers could both be efficiently isolated is tentatively discussed based on X‐ray crystallographic and 1H NMR spectroscopic analysis.
Cr(CO)3‐Activated Diels–Alder Reaction on Single‐Wall Carbon Nanotubes: A DFT Investigation
Authors: Nunzi Francesca , Sgamellotti Antonio , De Angelis Filippo
Published: February 2009

Breaking barriers: In agreement with experimental evidence, it was found by means of high‐level DFT calculations that the Cr(CO)3 metal fragment considerably reduces the reaction energy barrier—for both the concerted and stepwise reaction mechanisms (see graphic)—of the Diels–Alder reaction of butadiene on (5,5) carbon nanotubes.

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The reaction mechanism and the effect of Cr(CO)3 on the Diels–Alder reaction of butadiene on (5,5) carbon nanotube sidewalls have been investigated by high‐level DFT calculations. We investigated both concerted and stepwise reaction pathways on closed‐shell and open‐shell potential‐energy surfaces. In agreement with recent experimental evidence, we found the Cr(CO)3 metal fragment to considerably reduce the reaction energy barrier, both for the concerted and stepwise reaction mechanisms. The latter mechanism, previously found to be higher in energy with traditional substrates, appears to compete with the concerted mechanism on the carbon nanotube sidewalls. An analysis of the frontier molecular orbitals on the pristine and Cr(CO)3‐complexed carbon nanotubes allowed us to identify the reason for this inverted reactivity pattern and the role of the transition metal on the addition of the diene.
Mass transfer and deodorization efficiency in a countercurrent spray tower for low superficial gas velocities
Authors: Turpin A. , Couvert A. , Laplanche A. , Paillier A.
Published: February 2009

The aim of this study was to characterize mass transfer and deodorization efficiency in a countercurrent spray tower for low superficial gas velocities. The influence of operating parameters (UG = 0.005 to 0.025 m s−1, UL = 6.1 × 10−5 to 2.4 × 10−4 m s−1) on the liquid retention (εL), the drop diameter (dg), the interfacial area (a) and the overall liquid and gas phase mass transfer coefficients (KLa, KGa) were estimated. The spray efficiency of some malodorous compounds was also estimated. A negative influence of the superficial gas velocity was demonstrated, during the spraying of water or chemical neutralizing scrubbing solutions. There was also an increase with the liquid flow rate. Abatements obtained were very good with respect to ammonia (>90%), and acceptable for the other compounds.
BRCA1 and BRCA2 mutations in women of different ethnicities undergoing testing for hereditary breast‐ovarian cancer
Authors: Hall Michael J. , Reid Julia E. , Burbidge Lynn A. , Pruss Dmitry , Deffenbaugh Amie M. , Frye Cynthia , Wenstrup Richard J. , Ward Brian E. , Scholl Thomas A. , Noll Walter W.
Published: February 2009

BACKGROUND:

In women at increased risk for breast and ovarian cancer, the identification of a mutation in breast cancer gene 1 (BRCA1) and BRCA2 has important implications for screening and prevention counseling. Uncertainty regarding the role of BRCA1 and BRCA2 testing in high‐risk women from diverse ancestral backgrounds exists because of variability in prevalence estimates of deleterious (disease‐associated) mutations in non‐white populations. In this study, the authors examined the prevalence of BRCA1 and BRCA2 mutations in an ethnically diverse group of women who were referred for genetic testing.

METHODS:

In this cross‐sectional analysis, the prevalence of BRCA1 and BRCA2 mutations was assessed in a group of non‐Ashkenazi Jewish women who underwent genetic testing.

RESULTS:

From 1996 to 2006, 46,276 women who met study criteria underwent DNA full‐sequence analysis of the BRCA1 and BRCA2 genes. Deleterious mutations were identified in 12.5% of women, and recurrent deleterious mutations (prevalence >2%) were identified in all ancestral groups. Women of non‐European descent were younger (mean age, 45.9 years; standard deviation [SD], 11.6 years) than European women (mean age, 50 years; SD, 11.9 years; P < .001). Women of African (15.6%; odds ratio [OR], 1.3 [95% confidence interval (95% CI), 1.1‐1.5]) and Latin American (14.8%; OR, 1.2 [95% CI, 1.1‐1.4]) ancestries had a significantly higher prevalence of deleterious BRCA1 and BRCA2 mutations compared with women of Western European ancestry (12.1%), primarily because of an increased prevalence of BRCA1 mutations in those 2 groups. Non‐European ethnicity was associated strongly with having a variant of uncertain significance; however, reclassification decreased variant reporting (from 12.8%→5.9%), and women of African ancestry experienced the largest decline (58%).

CONCLUSIONS:

Mutation prevalence was found to be high among women who were referred for clinical BRCA1 and BRCA2 testing, and the risk was similar across diverse ethnicities. BRCA1 and BRCA2 testing is integral to cancer risk assessment in all high‐risk women. Cancer 2009. © 2009 American Cancer Society.
Intracranial dural metastases
Authors: Nayak Lakshmi , Abrey Lauren E. , Iwamoto Fabio M.
Published: February 2009

BACKGROUND:

Intracranial dural metastases (IDM) are found at autopsy in 9% of patients with advanced systemic cancer. However, to the authors' knowledge, IDM have not been studied systematically in the modern neuroimaging era. The objective of the current study was to evaluate the demographics, clinical presentation, imaging, treatment, and prognosis of patients with IDM.

METHODS:

The current study was a retrospective review of 122 patients with IDM diagnosed at Memorial Sloan‐Kettering Cancer Center between 1999 and 2006. Patients with concurrent brain or leptomeningeal metastases were excluded.

RESULTS:

Sixty‐one percent of the patients were women; the median age at diagnosis was 59 years, the median Karnofsky performance scale (KPS) at diagnosis was 80, and the median time to IDM diagnosis from initial cancer diagnosis was 37 months. Breast (34%) and prostate (17%) cancers were the most frequent primary tumors associated with IDM. Fifty‐six percent of patients had a single dural metastasis. On imaging, 70% had metastases of the overlying skull, 44% had dural tail metastases, 53% had vasogenic edema, and 34% had brain invasion. Direct extension from skull metastases was the most common mode of spread. Eighty‐three percent of patients had active systemic disease at the time of IDM diagnosis. A lower KPS and lung cancer were associated with worse overall survival. Surgical resection and chemotherapy improved progression‐free survival, but only resection was found to be associated with improved overall survival.

CONCLUSIONS:

IDM affect a significant proportion of cancer patients. KPS and status of systemic cancer should guide treatment decisions. Cancer 2009. © 2009 American Cancer Society.