bluuebunny/crossref_metadata_2025_split huggingface dataset:
Origin of the Regio‐ and Stereoselectivity in Palladium‐Catalyzed Electrophilic Substitution via Bis(allyl)palladium Complexes
Authors: Wallner Olov A. , Szabó Kálmán J. 
Published: September 2003

AbstractPalladium‐catalyzed allylic substitution of aryl allyl chlorides with aromatic and heteroaromatic aldehydes was performed in the presence of hexamethylditin. This procedure involves palladium‐catalyzed formation of transient allylstannanes followed by generation of a bis(allyl)palladium intermediate, which subsequently reacts with the aldehyde electrophile. The catalytic substitution reaction proceeds with high regio‐ and stereoselectivity. The stereoselectivity is affected by the steric and electronic properties of the allylic substituents. Various functionalities including NO2, COCH3, Br, and F groups are tolerated under the applied catalytic conditions. Density functional calculations at the B3PW91/DZ+P level of theory were applied to study the steric and electronic effects controlling the regio‐ and stereoselectivity of the electrophilic addition. The development of the selectivity was studied by modeling the various bis(allyl)palladium species occurring in the palladium‐catalyzed substitution of cinnamyl chloride with benzaldehyde. It was found that the electrophilic attack proceeds via a six‐membered cyclic transition state, which has a pronounced chair conformation. The regioselectivity of the reaction is controlled by the location of the phenyl group on the η1‐allyl moiety of the complex. The stereoselectivity of the addition process is determined by the relative configuration of the phenyl substituents across the developing carbon–carbon bond. The lowest energy path corresponds to the formation of the branched allylic isomer with the phenyl groups in anti configuration, which is in excellent agreement with the experimental findings.
Tetrameric, Trititanium(IV)‐Substituted Polyoxotungstates with an α‐Dawson Substructure as Soluble Metal‐Oxide Analogues: Molecular Structure of the Giant “Tetrapod” [(α‐1,2,3‐P2W15Ti3O62)4{μ3‐Ti(OH)3}4Cl]45−
Authors: Sakai Yoshitaka , Yoza Kenji , Kato Chika Nozaki , Nomiya Kenji 
Published: September 2003

AbstractThe preparation and structural characterization of the novel polyoxoanion [(α‐1,2,3‐P2W15Ti3O62)4{μ3‐Ti(OH)3}4Cl]45− (1 a; abbreviated to {TiO6}16; FW ∼16 000) which consists of four tri‐TiIV‐1,2,3‐substituted α‐Dawson substructures, four Ti(OH)3 bridging groups, and one encapsulated Cl− ion, are described. A water‐soluble, all‐inorganic composition compound of the tetrameric Ti‐O‐Ti‐bridged anhydride form, NaxH45−x[1 a]⋅y H2O (1; x=16–19, y=60–70), which was afforded by the reaction of the tri‐lacunary Dawson polyoxotungstate Na12[B‐α‐P2W15O56]⋅19 H2O with an excess of TiCl4 in aqueous solution, was obtained as analytically pure, homogeneous colorless crystals. Single‐crystal X‐ray structure analysis revealed that 1 a was an inorganic, giant “tetrapod”‐shaped molecule (inscribed to a sphere with a diameter of ∼32 Å) with approximately Td symmetry, in which the 16 edge‐ and/or corner‐shared TiO6 octahedra were contained. This number of TiO6 octahedra was larger than that found in other titanium(IV)‐substituted polyoxotungstates. Complex 1 was characterized by complete elemental analysis, TG/DTA, FTIR, UV/Vis absorption, and solution (31P and 183W) NMR spectroscopy. The longest wavelength band in the UV/Vis absorption spectra of 1 in water was attributed to the O→TiIV ligand‐to‐metal charge‐transfer (LMCT) transition: the wavelength of the LMCT band increased linearly as the number of TiO6 octahedra contained in the Keggin and Dawson polyoxoanions increased. The Tin chromophores formed in the Keggin and Dawson polyoxotungstates are water‐soluble analogues of solid TiO2 or SrTiO3 as light‐semiconductors and photocatalysts.
Cover Picture: Li3[ScN2]: The First Nitridoscandate(III)—Tetrahedral Sc Coordination and Unusual MX2 Framework (Chem. Eur. J. 17/2003)
Authors: Niewa Rainer , Zherebtsov Dmitri A. , Leoni Stefano 
Published: September 2003

AbstractThe cover picture shows a section of the crystal structure of the first nitridoscandate Li3[ScN2], in which for the first time Sc is observed in tetrahedral coordination. A the periodic nodal surface (PNS: grey mesh) separates Li+ atoms from the ${^{3}_{\infty }}$[ScN${_{4/2}^{3-}}$] network. Two isosurfaces of the electron localization function (ELF) at η=0.85 (light yellow) and η=0.74 (transparent orange) show the structuring of the outer‐core localization domain of Sc and the valence localization domain of N, respectively. For more details, see the paper by R. Niewa et al. on p. 4255 ff.
Differential connections of the temporal pole with the orbital and medial prefrontal networks in macaque monkeys
Authors: Kondo Hideki , Saleem Kadharbatcha S. , Price Joseph L. 
Published: September 2003

AbstractPrevious studies indicate that the orbital and medial prefrontal cortex (OMPFC) is organized into “orbital” and “medial” networks, which have distinct connections with cortical, limbic, and subcortical structures. In this study, retrograde and anterograde tracer experiments in monkeys demonstrated differential connections between the medial and orbital networks and the dorsal and ventral parts of the temporal pole. The dorsal part, including dysgranular and granular areas (TGdd and TGdg), is reciprocally connected with the medial network areas on the medial wall and gyrus rectus (areas 10m, 10o, 11m, 13a, 14c, 14r, 25, and 32) and on the lateral orbital surface (areas Iai and 12o). The strongest connections are with areas 10m (caudal part), 14c, 14r, 25, 32, and Iai. The agranular temporal pole (TGa) is connected with several areas, but most strongly with medial network area 25. The granular area around the superior temporal sulcus (TGsts) and the ventral dysgranular and granular areas (TGvd and TGvg) are reciprocally connected with the orbital network (especially areas 11l, 13b, 13l, 13m, Ial, Iam, and Iapm). TGsts is strongly connected with the entire orbital network, whereas areas TGvd and TGvg have lighter and more limited connections. Intrinsic connections within the temporal pole are also restricted to dorsal or ventral parts. Together with evidence that the dorsal and ventral temporal pole are differentially connected to auditory and visual areas of the superior and inferior temporal cortex, the results indicate separate connections between these systems and the medial and orbital prefrontal networks. J. Comp. Neurol. 465:499–523, 2003. © 2003 Wiley‐Liss, Inc.
Serial hearing organs in the atympanate grasshopper Bullacris membracioides (Orthoptera, Pneumoridae)
Authors: Van Staaden Moira J. , Rieser Michael , Ott Swidbert R. , Pabst Maria A. , Römer Heiner 
Published: September 2003

AbstractIn different insect taxa, ears can be found on virtually any part of the body. Comparative anatomy and similarities in the embryological development of ears in divergent taxa suggest that they have evolved multiple times from ubiquitous stretch or vibration receptors, but the homology of these structures has not yet been rigorously tested. Here we provide detailed analysis of a novel set of hearing organs in a relatively “primitive” atympanate bladder grasshopper (Bullacris membracioides) that is capable of signaling acoustically over 2 km. We use morphological, physiological, and behavioral experiments to demonstrate that this species has six pairs of serially repeated abdominal ears derived from proprioceptive pleural chordotonal organs (plCOs). We demonstrate continuity in auditory function from the five posterior pairs, which are simple forms comprising 11 sensilla and resembling plCOs in other grasshoppers, to the more complex anterior pair, which contains 2000 sensilla and is homologous to the single pair of tympanate ears found in “modern” grasshoppers. All 12 ears are morphologically differentiated, responsive to airborne sound at frequencies and intensities that are biologically significant (tuned to 1.5 and 4 kHz; 60–98 dB SPL), and capable of mediating behavioral responses of prospective mates. These data provide evidence for the transition in function and selective advantage that must occur during evolutionary development of relatively complex organs from simpler precursors. Our results suggest that ancestral insects with simple atympanate pleural receptors may have had hearing ranges that equal or exceed those of contemporary insects with complex tympanal ears. Moreover, auditory capability may be more prevalent among modern insect taxa than the presence of overt tympana indicates. J. Comp. Neurol. 465:579–592, 2003. © 2003 Wiley‐Liss, Inc.
C‐peptide enhances insulin‐mediated cell growth and protection against high glucose–induced apoptosis in SH‐SY5Y cells
Authors: Li Zhen‐guo , Zhang Weixian , Sima Anders A. F. 
Published: September 2003

AbstractBackgroundWe have previously reported that C‐peptide exerts preventive and therapeutic effects on diabetic neuropathy in type 1 diabetic BB/Wor‐rats and that it prevents duration‐dependent hippocampal apoptosis in the same animal model. In the present study, we examined human neuroblastoma SH‐SY5Y cells to examine whether C‐peptide stimulates cell proliferation/neurite outgrowth and whether it has antiapoptotic effects.MethodsFor neurite outgrowth, serum‐starved cultures were treated with C‐peptide and/or insulin or IGF‐1. Neurites were visualized with NF‐L antibody and measured morphometrically. Cell numbers were determined using an electronic cell counter. Scrambled C‐peptide was used as a negative control. For assessment of apoptosis, SH‐SY5Y cells were incubated with 100 mM glucose for 24 h, and the effects of C‐peptide and/or insulin or IGF‐1 were examined. Apoptosis was demonstrated by transferase‐mediated dUTP nick‐end labeling (TUNEL)/4,6‐diamidino‐2‐phenylindole (DAPI) stainings, flow cytometry and changes in the expression of Bcl2. Activation of insulin signaling intermediaries was determined by Western blots. Translocation of NF‐κB was demonstrated immunocytochemically.ResultsC‐peptide but not scrambled C‐peptide stimulated cell proliferation and neurite outgrowth. In the presence of 4 nM insulin, 3 nM C‐peptide significantly increased autophosphorylation of the insulin receptor (IR) but not that of the insulin‐like growth factor 1 receptor (IGF‐1R). It stimulated phosphoinositide 3‐kinase (PI‐3 kinase) and p38 mitogen‐activated protein (MAP) kinase activation, enhanced the expression and translocation of nuclear factor‐κB (NF‐κB), promoted the expression of Bcl2 and reduced c‐jun N‐terminal kinase (JNK) phosphorylation in excess of that of insulin alone.ConclusionsC‐peptide in the presence of insulin exerts synergistic effects on cell proliferation, neurite outgrowth and has in the presence of insulin an antiapoptotic effect on high glucose–induced apoptosis but less so on hyperosmolar‐induced apoptosis. These effects are likely to be mediated via interactions with the insulin signaling pathway. Copyright © 2003 John Wiley & Sons, Ltd.
The appearance of aggregated erythrocytes in the peripheral blood of individuals with insulin resistance
Authors: Justo Daniel , Marilus Rafael , Mardi Tamar , Tolchinsky Tatiana , Goldin Yelena , Rozenblat Meirav , Rogowski Ori , Yerushalmi Yair , Stern Naftali , Shenkerman Galina , Deutsch Varda , Zeltser David , Berliner Shlomo , Shapira Itzhak 
Published: September 2003

AbstractBackgroundInsulin resistance is associated with low‐grade inflammatory response. The probability that the acute‐phase response is associated with enhanced erythrocyte adhesiveness/aggregation was not explored.MethodsThe degree of erythrocyte adhesiveness/aggregation was evaluated by using a simple slide test. The insulin resistance was evaluated by insulin and glucose concentrations after a night of fasting. The inflammatory response was evaluated by variables of acute‐phase response.ResultsA significant correlation (r = −0.2, p = 0.02) was noted between insulin resistance expressed as the HOMA index and the degree of erythrocyte adhesiveness/aggregation. This was probably due to the concomitant acute‐phase response and the presence of increased amounts of inflammation‐sensitive proteins that were found to correlate significantly with the degree of erythrocyte adhesiveness/aggregation. In the multiple linear regression analysis, erythrocyte sedimentation rate and fibrinogen concentration but not HOMA index were found to correlate significantly (p < 0.0001 and p = 0.0007 respectively) with the degree of red blood cell adhesiveness/aggregation.ConclusionsInsulin resistance is associated with an enhanced degree of erythrocyte adhesiveness/aggregation and this is related to the presence of enhanced inflammation‐sensitive plasma proteins that are part of the acute‐phase response. These findings might have hemorheological consequences and might contribute to the pathophysiology of the insulin‐resistance syndrome. Copyright © 2003 John Wiley & Sons, Ltd.
Cross‐cultural comparisons of anxiety and depression in adults with type 1 diabetes
Authors: Lloyd Cathy E. , Zgibor Janice , Wilson Robb R. , Barnett Anthony H. , Dyer Philip H. , Orchard Trevor J. 
Published: September 2003

AbstractBackgroundSymptoms of depression and anxiety may be more prevalent in individuals with diabetes; however, little is known about possible differences with respect to social or cultural environment. The aim of this study was to examine cross‐cultural differences in prevalence and correlates of symptoms of anxiety and depression in two studies, one in the United Kingdom and one in the United States.MethodsAdults with type 1 diabetes participating in two studies in Birmingham, UK, and Pittsburgh, US, completed psychosocial questionnaires including the Beck Depression Inventory and the Beck Anxiety Scale.ResultsUK subjects were significantly more likely to report moderate–severe levels of anxiety compared to US subjects (17% vs 5%; p < 0.001). Similar proportions of UK and US subjects reported moderate–severe levels of depressive symptomatology (9% vs 7%). Gender differences in symptomatology were more apparent in the US sample than in the UK study population. Multiple regression analysis demonstrated that for the UK study, symptoms of depression, less physical activity and greater frequency of blood glucose monitoring were significantly associated with symptoms of anxiety. Symptoms of depression were also significantly associated with anxiety in the US sample. For UK subjects, depressive symptoms were significantly associated with higher anxiety scores, whereas in the US subjects, anxiety and smoking were significant independent correlates of depression.ConclusionsThese data suggest that there may be cultural and/or gender differences in the experience of symptoms of anxiety and depression, and also differences in the relationship between psychological symptomatology and diabetes self‐care. Our findings have implications for the understanding of the role psychosocial factors play in the management of diabetes. Copyright © 2003 John Wiley & Sons, Ltd.
Peripheral neuropathy and microangiopathy in rats with insulinoma: association with chronic hyperinsulinemia
Authors: Sugimoto Kazuhiro , Baba Masayuki , Suda Toshihiro , Yasujima Minoru , Yagihashi Soroku 
Published: September 2003

AbstractBackgroundHypoglycemia can precipitate or worsen peripheral neuropathy in patients with insulinoma or in diabetic patients on an intensive insulin regimen. It still remains unclear as to whether hyperinsulinemia itself is involved in neuropathic changes in these patients. We, therefore, explored the possible isolated effects of chronic hyperinsulinemia on neuropathic changes in insulinoma‐bearing rats (I‐rats).MethodsI‐rats were generated by a combined treatment with nicotinamide and streptozotocin. At 15 months after the treatment, they showed a wide range of the plasma insulin (PI) level with or without a decrease in the blood glucose (BG) level and were divided into three groups on the basis of the presence of hypoglycemia (BG < 2.5 mmol/L) or hyperinsulinemia (PI > 100 mU/L): the first exhibited only hypoglycemia, the second exhibited only hyperinsulinemia, and the third exhibited neither. Peripheral nerve function and structure as well as microvasculature were evaluated among these groups in addition to age‐matched untreated control rats (C‐rats).ResultsThe first group of hypoglycemic I‐rats showed a decrease (p < 0.05) in the axon/myelin ratio and an increase (p < 0.0001) in fibers undergoing axonal degeneration compared to C‐rats, while the other two groups did not. On the other hand, the second group of hyperinsulinemic I‐rats showed a decrease (p < 0.05) in the myelinated axonal size and an increase (all p < 0.05) in the F‐wave latency and the densities of myelinated fibers and endoneurial microvessels exhibiting endothelial hyperplasia, vascular wall thickening, or pericytes debris compared to the third group of isoglycemic I‐rats without hyperinsulinemia.ConclusionThese results suggest that hypoglycemia is associated with increased myelinated axonal damage, while hyperinsulinemia is associated with increased densities of small myelinated axons and endoneurial microvessels with microangiopathic changes in I‐rats. We, therefore, propose that the observed findings may be relevant to the complicated features of neuropathy in diabetic patients with chronic hyperinsulinemia. Copyright © 2003 John Wiley & Sons, Ltd.
The symptoms of hyperglycaemia in people with insulin‐treated diabetes: classification using principal components analysis
Authors: Warren Roderick E. , Deary Ian J. , Frier Brian M. 
Published: September 2003

AbstractBackground and aimsPeople with insulin‐treated diabetes commonly experience symptoms of hyperglycaemia, but the nature of these symptoms and their origins are poorly understood. The aims of this study were (1) to identify and classify the symptoms of hyperglycaemia experienced by people with insulin‐treated diabetes and (2) to identify patient characteristics associated with intensity of, and glycaemic threshold for, glycaemic symptoms.MethodsCommon hyperglycaemic symptoms were identified from preliminary interviews. Eighteen symptoms were used in a questionnaire. Four hundred participants estimated the intensities with which they experienced these symptoms during hyperglycaemia. Principal components analysis (PCA) was used to examine correlations between symptoms. Associations between symptom intensity, glycaemic threshold, and other characteristics were examined with multiple regression.ResultsIn total, 361 participants (90.2%) reported experiencing hyperglycaemic symptoms. PCA suggested four symptom groupings: (1) feeling tense, irritability, restlessness, poor concentration (agitation) (2) thirst, dry mouth, need to urinate, not feeling right, sweet/funny taste, weakness (osmotic) (3) dizziness, blurred vision, light‐headedness, weakness (neurological) (4) headache, nausea (malaise). Mean symptom intensity was associated with younger age. The median (range) estimated blood glucose threshold for symptom onset was 15 (8–30) mmol/L; there was a weak tendency for this threshold to be elevated in people who had impaired hypoglycaemia awareness.ConclusionsPeople with insulin‐treated diabetes commonly reported symptoms associated with hyperglycaemia. PCA separated these into four groups. Osmotic symptoms appear to be specific to hyperglycaemia; symptoms in the other groups may suggest underlying physiological mechanisms, but are relatively non‐specific. Symptoms are more intense in younger people and may be reported at lower blood glucose concentrations in people with normal awareness of hypoglycaemia. Copyright © 2003 John Wiley & Sons, Ltd.
Intranasally administered insulin intended for prevention of type 1 diabetes—a safety study in healthy adults
Authors: Kupila A. , Sipilä J. , Keskinen P. , Simell T. , Knip M. , Pulkki K. , Simell O. 
Published: September 2003

AbstractBackgroundIntranasally applied insulin is one of the antigen‐specific therapies currently tested in clinical type 1 diabetes prevention trials, for example, in the Type 1 Diabetes Prediction and Prevention Study (DIPP). The possibility that the therapy may cause hypoglycaemia or local irritation and the poorly known immunological safety of mucosal application of the antigen in healthy subjects prompted this study.MethodsWe used a randomised, placebo‐controlled, double‐blinded crossover study design with 3‐week treatment periods to study the effects of once‐daily intranasal application of human short‐acting insulin without absorption‐enhancing adjuvants in 20 non‐diabetic adults. The selected 60 IU dose of insulin was equivalent to the weight‐based dose used for the DIPP children. We investigated self‐monitored blood glucose concentrations, nasal insulin effects and induction of diabetes‐associated autoantibodies.ResultsThe two treatment periods showed no differences in blood glucose concentrations or in the frequency of blood glucose values higher than 3.0 mmol/L. Of the eight measured hypoglycaemic values, only one, which occurred during placebo therapy, was associated with symptoms. Rhinoscopy revealed no nasal irritation, and mucociliary clearance, nasal airway patency and nasal airflow resistance were not affected by the insulin therapy. Eleven subjects complained of transient nasal stinging or unpleasant odour and one subject reduced the dose because of nasal irritation. The treatment did not induce production of any of the four diabetes‐associated autoantibodies.ConclusionsShort‐term use of intranasal insulin without absorption enhancers was predominantly well tolerated, the risk of hypoglycaemia was minimal and no objective nasal adverse effects were detected. Copyright © 2003 John Wiley & Sons, Ltd.
C‐peptide makes a comeback
Authors: Wahren John 
Published: September 2003

AbstractProinsulin C‐peptide was for long considered to be without biological activity of its own. New findings demonstrate, however, that it is capable of eliciting both molecular and physiological effects, suggesting that C‐peptide is in fact a bioactive peptide. When administered in replacement doses to animal models or to patients with type 1 diabetes, C‐peptide ameliorates diabetes‐induced functional and structural changes in both the kidneys and the peripheral nerves. It augments blood flow in a number of tissues, notably skeletal muscle, myocardium, skin and nerve. These effects are thought to be mediated via a stimulatory influence on Na+,K+‐ATPase and on endothelial nitric oxide synthase. Specific binding of C‐peptide to cell membranes of intact cells and to detergent‐solubilized cellular components has been demonstrated, indicating the existence of cell‐surface binding sites for C‐peptide. A number of intracellular responses are elicited by C‐peptide, including a rise in Ca2+ concentration and activation of MAP‐kinase signaling pathways. Many but not all of C‐peptide's intracellular effects can be inhibited by pertussis toxin, supporting the notion that C‐peptide may interact via a G‐protein‐coupled receptor. Additional data suggest that C‐peptide may interact synergistically also in the insulin signaling pathway. Combined, the available observations show conclusively that C‐peptide is biologically active, even though its molecular mechanism of action is not as yet fully understood. The possibility that replacement of C‐peptide in patients with type 1 diabetes may serve to retard or prevent the development of long‐term complications should be evaluated. Copyright © 2003 John Wiley & Sons, Ltd.