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Workup
Kinds of Workup Selected AbstractsParietal Lobe Epilepsy: The Semiology, Yield of Diagnostic Workup, and Surgical OutcomeEPILEPSIA, Issue 6 2004Dong Wook Kim Summary: Purpose: To characterize the clinical features, the prognostic value, and diagnostic sensitivities of various presurgical evaluations and the surgical outcomes in parietal lobe epilepsy (PLE), we describe 40 patients who were diagnosed as having PLE, including 27 surgically treated patients. Methods: The diagnosis was established by means of a standard presurgical evaluation, including magnetic resonance imaging (MRI), fluorodeoxyglucose,positron emission tomography (FDG-PET), ictal single-photon emission tomography (SPECT), and scalp video-electroencephalography (EEG) monitoring, with additional intracranial EEG monitoring in selected cases. Results: Among the 40 patients, 27 experienced at least one type of aura. The most common auras were somatosensory (13 patients), followed by affective, vertiginous, and visual auras. The patients had diverse manifestations. Eighteen patients showed simple motor seizure, followed by automotor seizure, and dialeptic seizure. Two patients manifested generalized tonic,clonic seizures only, and 19 patients experienced more than one type of seizure. The surgical outcome was favorable in 22 of 26 patients including 14 who were seizure free. Patients with localized MRI abnormality had a higher probability to be seizure free, with marginal significance (p = 0.062), whereas other diagnostic modalities failed to predict the surgical outcome. In the seizure-free group, localization sensitivity was 64.3% by MRI, 50% by PET, 45.5% by ictal SPECT, and 35.7% by ictal EEG. The concordance rate of the various diagnostic modalities was higher in the seizure-free group than in the non,seizure-free group, although it did not reach statistical significance. Conclusions: Seizures, in the case of PLE, can manifest themselves in a wider variety of ways than was previously thought. Surgical outcome was favorable in most of the patients. MRI abnormality and concordance of different diagnostic modalities were associated with high seizure-free rate. [source] Metastatic pulmonary calcification in a dialysis patient: Case report and a reviewHEMODIALYSIS INTERNATIONAL, Issue S2 2006Christoph H. EGGERT Abstract A 19-year-old male presented with chest pain and dyspnea. He was anephric following nephrectomy for focal segmental glomerulosclerosis, had a subsequent failed transplant, and had been dialysis dependent for 3 years. Workup revealed hyperparathyroidism and an abnormal chest X-ray and computed tomography scan, significant for massive extra-skeletal pulmonary calcification. A markedly abnormal Technitium99 methylene diphosphonate (Tc99m-MDP) bone scan confirmed the clinical suspicion of metastatic pulmonary calcification. Metastatic pulmonary calcification (MPC) is common, occurring in 60% to 80% of dialysis patients on autopsy and bone scan series. It may lead to impaired oxygenation and restrictive lung disease. Typically, the calcium crystal is whitlockite rather than hydroxyapatite, which occurs in vascular calcification. Four major predisposing factors may contribute to MPC in dialysis patients. First, chronic acidosis leaches calcium from bone. Second, intermittent alkalosis favors deposition of calcium salts. Third, hyperparathyroidism tends to cause bone resorption and intracellular hypercalcemia. Finally, low glomerular filtration rate can cause hyperphosphatemia and an elevated calcium-phosphorus product. There may be other factors. Some authors suggest that the incidence of MPC in recent years may be lower due to improved dialysis techniques. The diagnosis is confirmed by biopsy, but can be suspected by typical findings on a Tc99m-MDP bone scan. Therapy is limited to ensuring adequate dialysis, correcting calcium-phosphorus product, and hyperparathyroidism; discontinuing vitamin D analogues may help. Conflicting reports show that transplantation may either improve or worsen the situation. MPC should be considered in dialysis patients who have characteristic abnormal chest radiography and/or pulmonary symptoms. [source] Exercise-induced cholangitis and pancreatitisHPB, Issue 2 2005JOHN G. TOUZIOS Abstract Background. Cholangitis requires bactibilia and increased biliary pressure. Pancreatitis may be initiated by elevated intraductal pressure. The sphincter of Oddi regulates pancreatobiliary pressures and prevents reflux of duodenal contents. However, following biliary bypass or pancreatoduodenectomy, increased intra-abdominal pressure may be transmitted into the bile ducts and/or pancreas. The aim of this analysis is to document that cholangitis or pancreatitis may be exercise-induced. Methods. The records of patients with one or more episodes of cholangitis or pancreatitis precipitated by exercise and documented to have patent hepatico- or pancreatojejunostomies were reviewed. Cholangitis was defined as fever with or without abdominal pain and transiently abnormal liver tests. Pancreatitis was defined as abdominal pain, with transient elevation of serum amylase and documented by peripancreatic inflammation on computerized tomography. Results. Twelve episodes of cholangitis occurred in six patients who had undergone hepaticojejunostomy for biliary stricture (N=3), Type I choledochal cyst (N=2), or pancreatoduodenectomy for renal cell carcinoma metastatic to the pancreas (N=1). Four episodes of pancreatitis occurred in two patients who had undergone pancreatoduodenectomy for ampullary carcinoma or chronic pancreatitis. Workup and subsequent follow-up for a median of 21 months have not documented anastomotic stricture. Each episode of cholangitis and pancreatitis was brought on by heavy exercise and avoidance of this level of exercise has prevented future episodes. Conclusion. Following biliary bypass or pancreatoduodenectomy, significant exercise may increase intra-abdominal pressure and cause cholangitis or pancreatitis. Awareness of this entity and behavior modification will avoid unnecessary procedures in these patients. [source] Severe generalized dystonia due to primary putaminal degeneration: Case report and review of the literature,MOVEMENT DISORDERS, Issue 3 2002Ruth H. Walker MB Abstract Putaminal lesions of a variety of etiologies may cause secondary dystonia. We report on a case of primary putaminal degeneration as a cause of severe childhood-onset generalized dystonia and review the literature of the pathology of dystonia. A 44-year-old patient with severe generalized childhood-onset dystonia and macrocephaly underwent neurological evaluation and neuropathological examination. Neurological examination was normal apart from dystonia and signs referable to prior cryothalamotomy. Workup for metabolic and genetic causes of dystonia was negative. Neuroimaging showed severe bilateral putaminal degeneration, which subsequently correlated with the neuropathological findings of gliosis, spongiform degeneration, and cavitation. The substantia nigra pars compacta contained a normal number of neurons but decreased tyrosine hydroxylase immunoreactivity. There were no histopathological markers of other metabolic or degenerative diseases. © 2002 Movement Disorder Society. [source] Resource Use and Cost of Diagnostic Workup of Women with Suspected Breast CancerTHE BREAST JOURNAL, Issue 1 2009David W. Lee PhD Abstract:, We estimated resource use and costs associated with a diagnostic workup for suspected breast cancer among Medicare beneficiaries. Using Medicare claims data, we found that the average cost of a diagnostic workup for suspected breast cancer,whether it eventuated in a breast cancer diagnosis or not,was $361, and did not vary by presentation (signs/symptoms or screening mammography). In the aggregate, we estimate that Medicare spends approximately $679 million annually on diagnostic workups for women with suspected breast cancer, and that false positive mammograms result in diagnostic costs of approximately $250 million. [source] Fatal Graft-Versus-Host Disease Presenting as Fever of Unknown Origin in a Pancreas-After-Kidney Transplant RecipientAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2008F. L. Weng Acute graft-versus-host disease (GVHD) is a rare complication of pancreas transplantation. We describe a 54-year-old male with type 1 diabetes who received a zero-antigen mismatched pancreas-after-kidney transplant from a pancreas donor who was homozygous at the HLA-B, -Cw, -DR, and -DQ alleles. Starting on postoperative day (POD) #22, the patient developed persistent fevers. Workup was notable only for low-grade cytomegalovirus viremia, which was treated. The fevers eventually disappeared. On POD #106, the patient was noted to have a diffuse erythematous rash. A skin biopsy was consistent with GVHD. Short tandem repeat DNA analysis of both peripheral blood lymphocytes and skin demonstrated mixed chimerism, confirming the diagnosis of GHVD. Soon after diagnosis, the patient developed pancytopenia and fevers and died of multiorgan failure on POD #145. Transplant clinicians should consider GVHD as a possible, although admittedly rare, cause of fevers of unknown origin in recipients of pancreas transplants. [source] A New Fluorous/Organic Amphiphilic Ether Solvent, F-626: Execution of Fluorous and High Temperature Classical Reactions with Convenient Biphase Workup to Separate Product from High Boiling Solvent.CHEMINFORM, Issue 39 2002Miroshi Matsubara Abstract For Abstract see ChemInform Abstract in Full Text. [source] Sentinel Lymph Node Biopsy in Cutaneous Squamous Cell Carcinoma: A Systematic Review of the English LiteratureDERMATOLOGIC SURGERY, Issue 11 2006AMY SIMON ROSS MD BACKGROUND Although most cutaneous squamous cell carcinoma (SCC) is curable by a variety of treatment modalities, a small subset of tumors recur, metastasize, and result in death. Although risk factors for metastasis have been described, there are little data available on appropriate workup and staging of patients with high-risk SCC. OBJECTIVE We reviewed reported cases and case series of SCC in which sentinel lymph node biopsy (SLNB) was performed to determine whether further research is warranted in developing SLNB as a staging tool for patients with high-risk SCC. METHODS The English medical literature was reviewed for reports of SLNB in patients with cutaneous SCC. Data from anogenital and nonanogenital cases were collected and analyzed separately. The percentage of cases with a positive sentinel lymph node (SLN) was calculated. False negative and nondetection rates were tabulated. Rates of local recurrence, nodal and distant metastasis, and disease-specific death were reported. RESULTS A total of 607 patients with anogenital SCC and 85 patients with nonanogenital SCC were included in the analysis. A SLN could not be identified in 3% of anogenital and 4% of nonanogenital cases. SLNB was positive in 24% of anogenital and 21% of nonanogenital patients. False-negative rates as determined by completion lymphadenectomy were 4% (8/213) and 5% (1/20), respectively. Most false-negative results were reported in studies from 2000 or earlier in which the combination of radioisotope and blue dye was not used in the SLN localization process. Complications were reported rarely and were limited to hematoma, seroma, cutaneous lymphatic fistula, wound infection, and dehiscence. CONCLUSIONS Owing to the lack of controlled studies, it is premature to draw conclusions regarding the utility of SLNB in SCC. The available data, however, suggest that SLNB accurately diagnoses subclinical lymph node metastasis with few false-negative results and low morbidity. Controlled studies are needed to demonstrate whether early detection of subclinical nodal metastasis will lead to improved disease-free or overall survival for patients with high-risk SCC. [source] Carcinoma En Cuirasse Presenting as Keloids of the ChestDERMATOLOGIC SURGERY, Issue 2 2004Kimberly Mullinax Background. Carcinoma en cuirasse is a form of metastatic cutaneous breast malignancy occurring most commonly on the chest as a recurrence of breast cancer, but it can be the primary presentation. Objective. To discuss the clinical features of carcinoma en cuirasse that distinguish it from hypertrophic scars and keloids of the chest. Method. We report a 63-year-old woman with primary cutaneous breast carcinoma presenting as keloid nodules on the chest that failed treatments for keloids. Biopsy revealed a pattern of breast carcinoma in the skin. Results. After further workup, no tumor was found in the deep breast tissue, but metastases were found in her axillary lymph nodes. Conclusions. Unusual keloid-like nodules or scars on the chest that fail to respond to therapy may be primary or metastatic malignancies, and adequate histologic verification should be obtained to avoid delay in the proper treatment. [source] The use of neuroimaging in the diagnosis of mitochondrial diseaseDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2010Seth D. Friedman Abstract Mutations in nuclear and mitochondrial DNA impacting mitochondrial function result in disease manifestations ranging from early death to abnormalities in all major organ systems and to symptoms that can be largely confined to muscle fatigue. The definitive diagnosis of a mitochondrial disorder can be difficult to establish. When the constellation of symptoms is suggestive of mitochondrial disease, neuroimaging features may be diagnostic and suggestive, can help direct further workup, and can help to further characterize the underlying brain abnormalities. Magnetic resonance imaging changes may be nonspecific, such as atrophy (both general and involving specific structures, such as cerebellum), more suggestive of particular disorders such as focal and often bilateral lesions confined to deep brain nuclei, or clearly characteristic of a given disorder such as stroke-like lesions that do not respect vascular boundaries in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS). White matter hyperintensities with or without associated gray matter involvement may also be observed. Across patients and discrete disease subtypes (e.g., MELAS, Leigh syndrome, etc.), patterns of these features are helpful for diagnosis. However, it is also true that marked variability in expression occurs in all mitochondrial disease subtypes, illustrative of the complexity of the disease process. The present review summarizes the role of neuroimaging in the diagnosis and characterization of patients with suspected mitochondrial disease. © 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:129,135. [source] Aspiration biopsy cytomorphology of primary pulmonary germ cell tumor metastatic to the brainDIAGNOSTIC CYTOPATHOLOGY, Issue 10 2009Haitham Arabi M.D. Abstract Extragonadal germ cell tumors are uncommon and such tumors originating from the lung parenchyma are extremely rare. This is a case of 68-year-old female who was admitted with complaints of right-sided weakness, inability to maintain her balance, right-sided headache, and bloody sputum. Her workup revealed two enhancing brain lesions and large lung mass involving the left lower lobe. Fine-needle aspiration (FNA) of the lung followed by craniotomy was performed and the patient was initially diagnosed with lung adenocarcinoma metastatic to the brain based on the cytomorphology of the lung FNA and histology of the brain mass. However, retrospective investigation revealed markedly elevated alpha fetoprotein (AFP) of which the cytopathologist was unaware at the time of diagnosis. A review of the cytology and surgical specimen slides, as well as immunohistochemistry (IHC) on the brain tumor and FNA cell block were preformed. On the basis of the slides review, clinical findings, and immunostaining results, a diagnosis of primary pulmonary mixed germ cell tumor, containing choriocarcinoma and yolk sac elements, with brain metastases, was retrospectively made. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source] HBME-1 and CK19 are highly discriminatory in the cytological diagnosis of papillary thyroid carcinomaDIAGNOSTIC CYTOPATHOLOGY, Issue 8 2008FRCPA, Min-En Nga MRCPath Abstract The cytologic diagnosis of papillary thyroid carcinoma is straightforward in most instances. However, there are some mimics including goitrous nodules and Hurthle cell neoplasms. Many studies have shown the combination of HBME-1 and CK19 expression to be useful in reaching a correct histologic diagnosis on tissue sections. We aim to assess the value of these markers in the setting of cell blocks prepared from needle aspiration specimens. We performed immunohistochemical staining of HBME-1 and CK19 on cell block material from 22 thyroid nodules that also had follow-up histology. Both CK19 and HBME-1 were strongly positive in all nine cases of papillary thyroid carcinoma, the latter showing distinct luminal accentuation. In the non-papillary carcinomas, none showed positivity for both HBME-1 and CK19. Two of six Hurthle cell neoplasms were positive for CK19, however all were negative for HBME-1. One of nine goitrous nodules was strongly positive for HBME-1 with luminal/membranous staining, but this were negative for CK19. The sensitivity, specificity and positive predictive value of HBME-1 in distinguishing between papillary thyroid carcinoma and goitrous nodules/Hurthle cell neoplasms were found to be 100%, 92.9% and 0.9, respectively; and that of HBME-1 and CK19 combination was 100%, 100% and 1. We thus conclude that the combination of positive HBME-1 (luminal/membranous) and CK 19 (cytoplasmic) staining on cell blocks of thyroid cytologic specimens is highly discriminatory in the diagnostic workup for papillary thyroid carcinoma. Diagn. Cytopathol. 2008; 36: 550,556. © 2008 Wiley-Liss, Inc. [source] Infarcted intraductal papilloma of the breast: Cytologic features with stage of infarctionDIAGNOSTIC CYTOPATHOLOGY, Issue 5 2006Akinori Ishihara M.D., F.I.A.C., Ph.D. Abstract Fine-needle aspiration cytology (FNAC) is being employed with increasing frequency for the pre-operative diagnostic workup of breast lesions. Although most cases show morphologic features very characteristic of specific entities, rare lesions with infarcted breast can cause problems in interpretation. We present cytologic findings in seven cases of an infarcted intraductal papilloma of the breast (IDPB) that was diagnosed by FNAC, and we also report the correlation of cytological features and stages of infarcted IDPB. In the early stage of infarction, numerous degenerative cells and necrotic debris were demonstrated. Isolated degenerative cells showed columnar, spindle, polygonal and fiber-like cells, with coagulated and smudged nuclei. Ghost cells were also seen. Extensive necrosis was demonstrated with a few sheets of ductal cells in the mid-stage of infarction. In the late stage of infarction, clusters of fibroblasts, ductal cells and necrotic debris were found. Knowledge of the characteristic cytologic pattern in different stages of infarcted IDPB may be helpful to suggest the probable pre-operative diagnosis of those lesions. Familiarity with this entity is important in preventing misdiagnosis of malignancy. Diagn. Cytopathol. 2006;34:373,376. © 2006 Wiley-Liss, Inc. [source] Unsuspected systemic amyloidosis diagnosed by fine-needle aspiration of the salivary gland: Case reportDIAGNOSTIC CYTOPATHOLOGY, Issue 1 2004Ph.D., Tamar Giorgadze M.D. Abstract Amyloidosis of the head and neck region may represent a local amyloidoma or a manifestation of systemic disease. Involvement of major salivary glands by either primary or secondary forms of amyloidosis is very rare. We describe a case of systemic amyloidosis that initially presented as submandibular gland mass and was diagnosed by fine-needle aspiration (FNA). A 69-year-old male presented with submandibular mass. His past medical history was significant for left forearm melanoma that was excised 6 years ago and tricuspid valve endocarditis after valvular replacement 3 months prior to FNA of the submandibular gland. The patient had no symptoms or clinical and laboratory data suggestive of amyloidosis. FNA specimen showed salivary gland tissue and abundant amorphous material, which stained positive for amyloid with Congo red stain and showed typical birefringence when examined by polarized microscopy. Further workup of the patient revealed generalized amyloidosis with multiorgan involvement by the disease. This case demonstrates that FNA can be a useful technique in the diagnosis of unsuspected amyloidosis. Diagn. Cytopathol. 2004;31:57,59. © 2004 Wiley-Liss, Inc. [source] Echocardiographic Diagnosis of Apical Hypertrophic Cardiomyopathy with Optison ContrastECHOCARDIOGRAPHY, Issue 6 2002Jagruti Patel M.D. We describe a case of obstructive apical hypertrophic cardiomyopathy in a 61-year-old Caucasian female with a history of chest pain syndrome. The patient was referred to the echo lab by her nuclear cardiologist, who was impressed by her abnormal stress nuclear perfusion scan that showed marked increased uptake of radioisotope at the left ventricular (LV) apex. The patient had deep negative T waves on her electrocardiogram similar to those originally described in the Japanese population. Transthoracic echocardiography with native harmonic imaging was suboptimal for visualizing LV segments. Therefore, 0.5 cc of Optison contrast was given intravenously, with repeat transthoracic imaging confirming the diagnosis. The patient and her family were referred for additional genetic testing and cardiovascular workup. [source] Improved workup for glycosaminoglycan disaccharide analysis using CE with LIF detectionELECTROPHORESIS, Issue 22 2008Alicia M. Hitchcock Abstract This work describes improved workup and instrumental conditions to enable robust, sensitive glycosaminoglycan (GAG) disaccharide analysis from complex biological samples. In the process of applying CE with LIF to GAG disaccharide analysis in biological samples, we have made improvements to existing methods. These include (i) optimization of reductive amination conditions, (ii) improvement in sensitivity through the use of a cellulose cleanup procedure for the derivatization, and (iii) optimization of separation conditions for robustness and reproducibility. The improved method enables analysis of disaccharide quantities as low as 1,pmol prior to derivatization. Biological GAG samples were exhaustively digested using lyase enzymes, the disaccharide products and standards were derivatized with the fluorophore 2-aminoacridone and subjected to reversed polarity CE-LIF detection. These conditions resolved all known chondroitin sulfate (CS) disaccharides or 11 of 12 standard heparin/heparan sulfate disaccharides, using 50,mM phosphate buffer, pH 3.5, and reversed polarity at 30,kV with 0.3,psi pressure. Relative standard deviation in migration times of CS ranged from 0.1 to 2.0% over 60 days, and the relative standard deviations of peak areas were less than 3.2%, suggesting that the method is reproducible and precise. The CS disaccharide compositions are similar to those obtained by our group using tandem MS. The reversed polarity CE-LIF disaccharide analysis protocol yields baseline resolution and quantification of heparin/heparan sulfate and CS/dermatan sulfate disaccharides from both standard preparations and biologically relevant proteoglycan samples. The improved CE-LIF method enables disaccharide quantification of biologically relevant proteoglycans from small samples of intact tissue. [source] Unilateral Intracarotid Amobarbital Procedure for Language LateralizationEPILEPSIA, Issue 11 2005Jörg Wellmer Summary:,Purpose: The determination of language dominance as part of the presurgical workup of patients with pharmacoresistant epilepsies has experienced fundamental changes. With the introduction of noninvasive functional magnetic resonance imaging (fMRI), the number of patients receiving intracarotid amobarbital procedures (IAPs) for assessment of language dominance has decreased considerably. However, recent studies show that because of methodologic limitations of fMRI, IAP remains an important tool for language lateralization. The current study examines whether unilateral instead of bilateral IAP is an adequate way to apply IAP with reduced invasiveness. Methods: We retrospectively examine the predictive value of unilateral IAP for the results of bilateral IAP based on a sample of 75 patients with various types of language dominance. Target parameters are the prediction of the language-dominant hemisphere and the identification of patients with atypical language dominance. For language assessment based on unilateral IAP, we introduce the measure hemispheric language capacity (HLC). Results: Unilateral IAP performed on the side of intended surgery quantifies language capacity contralateral to the intended surgery. It detects atypical (bilateral or right) language dominance in the majority of patients. Experience with a separate series of 107 patients requiring presurgical language lateralization shows that in >80%, bilateral IAPs are redundant. Conclusions: Unilateral IAP is principally sufficient for language lateralization in the presurgical evaluation of patients with pharmacoresistant epilepsies. Necessity of bilateral IAP is restricted to few indications (e.g., callosotomy). In times of noninvasive language lateralization, we propose unilateral IAP as the method of choice for the verification of doubtful (bilateral) fMRI activation patterns. [source] The Transient Titanocene(II): Direct Synthesis from Solvated Titanium(II) Chloride and Cyclopentadienylsodium and Ensuing Interception with Diphenylacetylene as 1,1-Bis(cyclopentadienyl)-2,3,4,5-tetraphenyltitanacyclopentadiene,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2007John J. Eisch Abstract For the first time the unstable titanocene(II) has been directly synthesized by the Wilkinson metallocene approach, namely the interaction of a THF-soluble form of titanium(II) chloride with two equivalents of cyclopentadienylsodium in THF solution at 0°,25 °C. Because of the transient existence of the titanocene(II) thereby obtained, it could only be chemically trapped in high yield as 1,1-bis(cyclopentadienyl)-2,3,4,5-tetraphenyltitanacyclopentadiene by two equivalents of diphenylacetylene, if the acetylene was added at 25 °C, without removal of the by-product LiCl and NaCl. If the addition of the acetylene was delayed, in order to filter off the LiCl and NaCl from the reaction mixture, then no trace of the titanacyclopentadiene derivative was found upon hydrolytic workup. Instead, a significant portion of the acetylene was found to have undergone hydrotitanation. This finding is clear evidence that the titanocene(II) had undergone a precedented rearrangement to a known dimer having the structure of a titanocene(III) hydride with a fulvalene bridge between the titanium centers. We suggest that the LiCl and NaCl present in the unfiltered reaction mixture form a dichloro complex with titanocene(II) and thereby retard its dimerizing rearrangement to the titanocene(III) hydride. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Lithium and Potassium Amides of Sterically Demanding AminopyridinesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2004Natalie M. Scott Abstract The reaction of Grignard compounds of 1-bromo-2,4,6-diisopropylbenzene (1) or 1-bromo-2,6-dimethylbenzene (2), formed in situ, with 2,6-dibromopyridine in the presence of a catalytic amount of [(dme)NiBr2] (dme = 1,2-dimethoxyethane) and tricyclohexylphosphane (1:2 ratio) leads to the corresponding monoarylated bromopyridines. These bromopyridines undergo Pd-catalysed aryl amination (Buchwald,Hartwig amination) with 2,6-diisopropylaniline giving rise to (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridin-2-yl]amine (Ap*H) and (2,6-diisopropylphenyl)[6-(2,6-dimethylphenyl)pyridin-2-yl]amine (Ap,H) (Ap = aminopyridinate). Deprotonation of Ap*H in diethyl ether using BuLi results (after workup in hexane) in a colourless crystalline material. X-ray structural analysis reveals it to be a monomeric three-coordinate lithium aminopyridinate. In toluene solution, an equilibrium between [(Ap*Li)2] (in excess at room temperature) and [Ap*Li(OEt2)] (prominent at low temperature) is observed. Reaction of Ap,H with BuLi in diethyl ether gives rise to [Ap*LiAp*Li(OEt2)]. Deprotonation of Ap*H and Ap,H using KH leads to [Ap*K]n and [Ap,K],, respectively. [Ap,K], is a rare example of a crystalline organometallic polymer, as determined by X-ray analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] MRI evidence of bilateral hippocampal sclerosis in amnestic mild cognitive impairmentEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2006M. Sepe-Monti We present the case of a man affected by amnestic mild cognitive impairment (aMCI) who showed bilateral hippocampal sclerosis at magnetic resonance imaging (MRI). We argue the concept that aMCI is heterogeneous syndrome and suggested the utility of coronal T2-weighted MRI images in the routine dementia workup. [source] 3,4-Dihydro-3H -pyrrol-2-imines as Conformationally Restrained 1,3-Diazabutadienes: Synthesis, Structural Properties and Protonation,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2009Simon Janich Abstract 5-Aryl-3,3,4,4-tetramethyl-3,4-dihydro-3H -pyrrol-2-imines,conformationally restrained 1,3-diazabuta-1,3-diene derivatives, were easily prepared by treating aryllithium species with 2,2,3,3-tetramethylsuccinonitrile (1). Trapping the reaction intermediate with chlorotrimethylsilane gave N -silylated compounds 2a,e, whereas aqueous workup gave N-H derivatives 3a,b. Pyrenyl-substituted compound 3b was characterised by X-ray diffraction studies, revealing the presence of both intermolecular aromatic face-to-face contacts and the formation of homodimers by twofold H-bonding. N -Silylated derivatives 2a,d were used successfully as nucleophilic components in palladium-catalysed C,N bond-forming reactions to obtain N -arylated compounds 5b,h,j,k,m and 7a,d. The UV spectra of compounds 5 and 7 exhibit long wavelength absorptions up to 462 nm for 7d, thus indicating extended ,,,* conjugation. Dihydropyrrolimine-based compounds with larger conjugated aryl substituents in the 5-position react with Brønsted and Lewis acids displaying a significant colour change that could be used to estimate the pKb of 3a to a value of ,4.5. Derivatives 2c,e and 3a,b, which are not N -arylated, are fluorescent with a Stokes shift of 107 nm (6034 cm,1) for 3a. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Bromodimethylsulfonium Bromide Catalyzed Three-Component Mannich-Type ReactionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2008Abu T. Khan Abstract Bromodimethylsulfonium bromide catalyzes Mannich-type reactions of a variety of aldimines, generated in situ from aldehydes and anilines, with enolizable ketones or diethyl malonate in three-component reactions to afford the corresponding ,-amino carbonyl compounds. The salient features of this protocol are: shorter reaction times, simplicity of the procedure, good to excellent yields, avoidance of aqueous workup and column-chromatographic separations, and high stereoselectivities.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] The Extraordinary Cocatalytic Action of Polymethylaluminoxane (MAO) in the Polymerization of Terminal Olefins by Metallocenes: Chemical Change in the Group 4 Metallocene Dimethyl Derivatives Induced by MAO,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2005John J. Eisch Abstract In the polymerization of olefins with Group 4 metallocene dichlorides or dimethyl derivatives as procatalysts the use of polymethylaluminoxane (MAO) as the cocatalyst, especially in extreme excess (102,103 times the metallocene equivalent), has been shown to have an extraordinary accelerating effect on the rate of olefin polymerization, when compared with the cocatalytic action of alkylaluminum halides. In attempts at explaining the greatly superior catalytic activity of MAO in olefin polymerization (the MAO conundrum), hypotheses have generally paralleled the steps involved in the cocatalytic action of RnAlCl3,n, namely the alkylation of Cp2MtCl2, ionization of Cp2Mt(R)Cl into the metallocenium cation, [Cp2Mt,R]+, and anion, [Rn,1AlCl4,n], and subsequent ion-pair separation. In order to understand any differences in catalytic action between such cocatalysts, we have studied the individual action of MAO (100 equiv.) and of MeAlCl2 (1,2 equiv.) on each of the Group 4 metallocene derivatives, Cp2TiCl2, Cp2ZrCl2, Cp2Ti(CH3)2 and Cp2Zr(CH3)2. With MeAlCl2 each of the metallocene derivatives appeared to form the cation, [Cp2Mt,CH3]+, with greater (Ti) or lesser (Zr) ease, because an alkyne such as diphenylacetylene was then found to insert into the Mt,CH3 bond stereoselectively. In striking contrast, treatment of each metallocene with MAO gave two reactions very different from MeAlCl2, namely a steady evolution of methane gas upon mixing and a finding upon hydrolytic workup that the diphenylacetylene present had undergone no insertion into the Mt,CH3 bond but instead had been reductively dimerized completely to (E,E)-1,2,3,4-tetraphenyl-1,3-butadiene. To account for this astonishing difference in chemical behavior between MAO and MeAlCl2 in their cocatalytic activation of Group 4 metallocenes to olefin polymerization, it is necessary to postulate a novel, unique sequence of reaction steps occurring between MAO and the metallocene. If one starts with the metallocene dichloride, then the free TMA present in the MAO would generate the Cp2Mt(CH3)2. This metallocene dimethyl derivative, complexed with an oligomeric MAO unit, would undergo a transfer-epimetallation with added olefin or acetylene to form a metallacyclopropane or metallacyclopropene, respectively. With added diphenylacetylene the resulting 2,3-diphenylmetallacyclopropene would be expected rapidly to insert a second alkyne to form the 2,3,4,5-tetraphenyl-1-metallacyclopentadiene. Simple hydrolysis of the latter intermediate would generate (E,E)-1,2,3,4-tetraphenyl-1,3-butadiene while alternative workup with D2O would give the 1,4-dideuterio derivative of this butadiene. Both such expectations were confirmed by experiment. In the case of added olefin, similar metallacyclopropane and metallacyclopentane intermediates should be produced until ring opening of the latter five-membered ring leads to an open-chain zwitterion, a process having ample precedent in the research of Gerhard Erker. The solution to the MAO conundrum then, namely the extraordinary cocatalytic activity of MAO in olefin polymerization by metallocenes, lies in the unique catalytic activation of the Group 4 metallocene dimethyl derivative, which occurs by transfer-epimetallation of the olefin monomer by the Cp2Mt(CH3)2,MAO complex. The most advantageous Lewis acidic sites in the MAO,oligomeric mixture for such metallocene,MAO complexation are suggested to be terminal Me2Al,O,AlMe, segments of an open-chain oligomer. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Quaternary Ammonium-Supported Scavenger Reagents for Acids and ElectrophilesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2004Noha Ghanem Abstract The present article describes how we devised new quaternary ammonium-supported quench reagents (TAMA-Cl and BAX-sulfate) for scavenging acids and excess electrophiles from crude reaction mixtures. TAMA-Cl is liquid at room temperature, but is very glutinous and has to be used in aqueous solution. It removes unchanged electrophiles very efficiently. An aqueous preparation of TAMA-Cl may be easily added in automated syntheses, and high-throughput phase-separation techniques should allow purification of scavenger-containing reaction mixtures. However, workup with TAMA-Cl is more complex than simple filtration. Recognizing this major advantage of solid-phase syntheses, we designed BAX-sulfate, a highly crystalline scavenger reagent that allows reaction workup to be simplified to a single filtration and evaporation of solvent. BAX-sulfate reacts with electrophiles, quenches acids and precipitates quantitatively when diethyl ether is added. It even precipitates from methanol solutions. With BAX-sulfate the workup stage uses simple filtration to make crude separations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Cardiovascular Risk Assessment and TriptansHEADACHE, Issue 2004Vasilios Papademetriou MD Identifying the patient for whom triptans are contraindicated because of recognized, diagnosed cardiovascular disease is relatively straightforward. Determining whether a patient with potential unrecognized cardiovascular disease is an appropriate candidate for triptan therapy, however, constitutes a difficult challenge, especially in the absence of a framework for workup of patients. This article discusses the pathophysiology of coronary heart disease and issues involved in assessing cardiovascular risk, and it attempts to provide a framework for cardiovascular risk assessment that can be applied to decisions for prescribing triptans. Current guidelines for cardiovascular risk assessment allow stratification of patients to low, intermediate, or high risk of coronary heart disease events. This framework for risk assessment can be applied to decisions for prescribing triptans. Cardiovascular risk-assessment algorithms discussed elsewhere in this supplement suggest that patients at low risk (1 or no risk factors) of coronary heart disease can be prescribed triptans without the need for a more intensive cardiovascular evaluation. Conversely, patients with established coronary heart disease or coronary heart disease risk equivalents should not be prescribed triptans according to the current prescribing recommendations. Patients at intermediate risk (2 or more risk factors) of coronary heart disease require cardiovascular evaluation before triptans can be prescribed. Current understanding suggests that the risk of future acute coronary events is a function of the absolute number of vulnerable plaques present, a variable that cannot be accurately determined using available technology or risk-prediction models. Cardiovascular risk-assessment guidelines should be evaluated in the context of this limitation. [source] An Efficient Synthesis of Novel Hexahydropyrido[2,3- d]pyrimidine Derivatives from (Arylmethylidene)pyruvic Acids (=(3E)-4-Aryl-2-oxobut-3-enoic Acids) in Aqueous MediaHELVETICA CHIMICA ACTA, Issue 5 2009Saeed Balalaie Abstract A series of new hexahydropyrido[2,3- d]pyrimidine derivatives 3 were synthesized by the cyclocondensation reaction of (arylmethylidene)pyruvic acids (=(3E)-4-aryl-2-oxobut-3-enoic acids) 1 and 6-aminouracils (=6-aminopyrimidine-2,4(1H,3H)-diones) 2 in H2O under reflux conditions (Scheme,1, Table). This novel protocol has the advantages of facility, of easy workup, of high yields, and of an environmentally benign procedure. The structures of compounds 3a,3f were corroborated spectroscopically (IR, 1H- and 13C-NMR, and EI-MS). A plausible mechanism for the reaction is proposed (Scheme,2). [source] Synthesis of Some Novel Thioxanthenone-Fused Azacrown Ethers, and Their Use as New Catalysts in the Efficient, Mild, and Regioselective Conversion of Epoxides to , -Hydroxy Thiocyanates with Ammonium ThiocyanateHELVETICA CHIMICA ACTA, Issue 7 2007Hashem Sharghi Abstract The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in the presence of a series of new 9H -thioxanthen-9-one-fused azacrown ethers, i.e., 7,11 (Scheme,1), and also of dibenzo[18]crown-6 (12), Kryptofix®22 (13), and benzo[15]crown-5 (14) were studied (Tables 1 and 2). The epoxides were subjected to cleavage by NH4SCN in the presence of these catalysts under mild conditions in various aprotic solvents. Reagents and conditions were identified for the synthesis of individual , -hydroxy thiocyanates in high yield and with more than 90% regioselectivity. The results can be discussed in terms of a four-step mechanism (Scheme,2): 1) formation of a complex between catalyst and NH4SCN, 2) release of SCN, from the complex, 3) reaction of the released SCN, at the sterically less hindered site of the epoxide, and 4) regeneration of the catalyst. The major advantages of this method are the high regioselectivity, the simple regeneration of the catalyst, the reuse of it through several cycles without a decrease of activity, and the ease of workup of the reaction mixtures. [source] Are Oxazolidinones Really Unproductive, Parasitic Species in Proline Catalysis?HELVETICA CHIMICA ACTA, Issue 3 2007Experiments Pointing to an Alternative View, Thoughts Abstract The N,O-acetal and N,O-ketal derivatives (oxazolidinones) formed from proline, and aldehydes or ketones are well-known today, and they are detectable in reaction mixtures involving proline catalysis, where they have been considered ,parasitic dead ends'. We disclose results of experiments performed in the early 1970's, and we describe more recent findings about the isolation, characterization, and reactions of the oxazolidinone derived from proline and cyclohexanone. This oxazolidinone reacts (THF, room temperature) with the electrophiles , -nitrostyrene and chloral (=trichloroacetaldehyde), to give the Michael and aldol adduct, respectively, after aqueous workup (Scheme,5). The reactions occur even at ,75° when catalyzed with bases such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or EtN(i-Pr)2 (DIPEA) (10%; Table,1). It is shown by NMR (Figs.,1 and 3) and IR analysis (Figs.,2 and 4) that the primarily detectable product (before hydrolysis) of the reaction with the nitro-olefin is again an oxazolidinone. When dissolved in hydroxylic solvents such as MeOH, ,hexafluoroisopropanol' ((CF3)2CHOH; HFIP), AcOH, CF3COOH, or in LiBr-saturated THF, the ring of the oxazolidinone from cyclohexanone and proline opens up to the corresponding iminium ion (Tables,2,4), and when treated with strong bases such as DBU (in (D8)THF) the enamino-carboxylate derived from proline and cyclohexanone is formed (Scheme,8). Thus, the two hitherto putative participants (iminium ion and enamine) of the catalytic cycle (Scheme,9) have been characterized for the first time. The commonly accepted mechanism of the stereoselective C,C- or C,X-bond-forming step (i.e., A,D) of this cycle is discussed and challenged by thoughts about an alternative model with a pivotal role of oxazolidinones in the regio- and diastereoselective formation of the intermediate enamino acid (by elimination) and in the subsequent reaction with an electrophile (by trans -addition with lactonization; Schemes,11,14). The stereochemical bias between endo - and exo -space of the bicyclo[3.3.0]octane-type oxazolidinone structure (Figs.,5 and 6) is considered to possibly be decisive for the stereochemical course of events. Finally, the remarkable consistency, with which the diastereotopic Re -face of the double bond of pyrrolidino-enamines (derived from proline) is attacked by electrophiles (Schemes,1 and 15), and the likewise consistent reversal to the Si -face with bulky (Aryl)2C-substituents on the pyrrolidine ring (Scheme,16) are discussed by invoking stereoelectronic assistance from the lone pair of pyramidalized enamine N-atoms. [source] Photocycloaddition of Cyclohex-2-enones to Penta-1,2,4-trieneHELVETICA CHIMICA ACTA, Issue 5 2006Britta Lohmeyer Abstract Dihydrothiinone 9a undergoes photocycloaddition regioselectively to all three CC bonds of penta-1,2,4-triene (10), the relative stabilities of the biradical intermediates determining the product distribution. In contrast, cyclohexenone 9b and dihydropyranone 9c afford more complex mixtures of bicyclo[4.2.0]octanones, which also turn out to be less stable on chromatographic workup, reflecting the higher strain due to the shorter bond lengths (CO and CC vs. CS) in the six-membered rings, respectively. [source] Highly efficient and chemoselective acetalization of carbonyl compounds catalyzed by new and reusable zirconyl triflate, ZrO(OTf)2HETEROATOM CHEMISTRY, Issue 3 2009Majid Moghadam Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3-dioxanes and 1,3-dioxolane with 1,3-propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf)2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:131,135, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20523 [source] | |||||||||||||||||||||||||||||||||||||||||||||||||