bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Stochastic Model for Coupled Enzyme System
Authors: Sen Pali 
Published: May 2007

AbstractThe molecular biology of transformed cancer cells singles out key enzymes as sensitive targets of anti‐cancer drugs. Here we use one substrate–one intermediate–one final product model for a coupled enzyme system. The transfer rates for the mechanism are taken as continuous but subject to random fluctuations. Explicit formulae for the first moments of the distribution of the process are obtained. These formulae allow us to take into account not only the variability between the subjects, but also the variability of the process for a single subject. The present results allow us also to build the prediction interval for a particular time period given the observations for some preceding moments.
Some Mathematical Properties of Cumulative Damage Models Regarding Their Application in Cancer Epidemiology
Authors: Becker Nikolaus , Rittgen Werner 
Published: May 2007

AbstractIn an earlier paper, cumulative damage models (CD models) were proposed for modelling the epidemiological aspects of carcinogenesis. In the present paper, further, mainly mathematical support is given for the adequacy of this approach. In the first place, this concerns the aspect that the cumulative damage process is a compound Poisson process. Secondly, it will be demonstrated that the CD models can be considered as a formal generalization of certain well‐known special carcinogenesis models. A more intensive investigation of these models themselves makes it evident that, on account of their mathematical qualities, they will possibly place very efficient new measures at the disposal of epidemiology. A diffusion approximation, however, does, after first experiments, not appear to make the handling of the models any easier but, on the contrary, to lead to a loss of certain pleasant qualities.
Indian Biotech Bazaar: A swot analysis
Authors: Kumar Abhishek 
Published: May 2007

AbstractBiotechnology is a life science‐based technique especially used in agriculture, medicine and food sciences. It is generally defined as the manipulation in organisms to generate products for the welfare of the world. Biotechnology combines disciplines such as genetics, biochemistry, microbiology, and cell biology along with information technology, chemical engineering, robotics etc. It includes basic industries such as food processing, tissue culture, plant development and other sophisticated ones such as recombinant therapeutics and diagnostics. Biotechnology, globally recognized as a rapidly emerging and far‐reaching technology, is aptly described as the “technology of hope” for its promise of food, health and environmental sustainability. In India, biotechnology employs more than 10 000 people and generates roughly US$ 500 million in revenue annually. The biotechnology market has increased its sales from Rs. 50 billion in 1997 to Rs.70 billion in 2000, and is expected to cross Rs. 240 billion by the year 2010. In India, the human health biotech products account for 60% of the total market; agribiotech and veterinary 25%, medical devices, contract research and development (R&D), reagents and supplies constitute the remaining 15% Moreover, to facilitate foreign investment, capital and government policies are being revised. Other important industries include industrial enzyme manufacture, bioinformatics, and medical devices. Biotechnology has had limited appeal so far on our capital markets, and we have less then a dozen biotech companies listed on the public markets.
Amphetamine effects on brain protein structure and oxidative stress as revealed by FTIR microspectroscopy
Authors: Rodríguez‐Casado A. , Alvarez I. , Toledano A. , de Miguel E. , Carmona P. 
Published: May 2007

AbstractAmphetamines are psychostimulants abused by man, that eventually leads to drug dependence. Amphetamine administration to rodents has been shown to provoke significant neurotoxicity involving dopaminergic nerve terminal degeneration. However, little information related to the effect of amphetamines on reactive oxygen species (ROS) production and neurotoxicity in brain is currently available. Herein we report the biochemical alterations of lipids and proteins in brain sections from amphetamine‐treated rodents using infrared microspectroscopy, immunohistochemistry, and immunoblotting. The spectroscopic changes reveal for the first time the formation of β‐sheet‐rich proteins in the cortex, but no significant protein alterations are visible in hippocampus region where hydroperoxide concentration is found to be lower relative to cortex. These result suggest that ROS generated by amphetamine‐mediated oxidative stress induce formation β‐sheet‐rich proteins which can be of amyloid β‐like character. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 437–446, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Molecular Assemblies from Imidazolyl‐Containing Haloalkenes and Haloalkynes: Competition between Halogen and Hydrogen Bonding
Authors: Bouchmella Karim , Boury Bruno , Dutremez Sylvain G. , van der Lee Arie 
Published: May 2007

AbstractThe structural characterization of molecular assemblies constructed from imidazolyl‐containing haloalkenes and haloalkynes is reported. 1‐(3‐Iodopropargyl)imidazole (2) and 1‐(2,3,3‐triiodoallyl)imidazole (5) were synthesized from 1‐propargylimidazole (1). In the solid state, these wholly organic modules self‐assemble through N⋅⋅⋅I halogen‐bonding interactions, thus giving rise to polymeric chains. The N⋅⋅⋅I interaction observed in 2 (d(N⋅⋅⋅I)=2.717 Å, ∢C(sp)‐I⋅⋅⋅N=175.8°) is quite strong relative to previously reported data. The N⋅⋅⋅I interaction in 5 (d(N⋅⋅⋅I)=2.901 Å, ∢C(sp2)‐I⋅⋅⋅N=173.6°) is weaker, in accordance with the order C(sp)‐X←base>C(sp2)‐X←base. Compound 5 was found to give a 1:1 cocrystal 4 with morpholinium iodide (6). In the X‐ray crystal studies of 4, N⋅⋅⋅I halogen‐bonding interactions similar to those observed in 5 were shown not to be present, as the arrangement of the molecules is governed by two interwoven hydrogen‐bonding networks. The first network involves N‐H⋅⋅⋅O interactions between nearby morpholinium cations, and the second network is based on N‐H⋅⋅⋅N hydrogen bonding between morpholinium cations and imidazolyl groups. Both hydrogen‐bonding schemes are charge‐assisted. Halogen bonding is not completely wiped out, however, as the triiodoalkene fragment forms a halogen bond with an iodide anion in its vicinity (d(I⋅⋅⋅I)=3.470 Å, ∢C(sp2)‐I⋅⋅⋅I=170.7°). X‐ray crystal studies of 6 show a completely different arrangement from that observed in 4, namely, N‐H⋅⋅⋅O interactions are not present. In crystalline 6, morpholinium cations are interconnected through C‐H⋅⋅⋅O bridges (d(H⋅⋅⋅O)=2.521 and 2.676 Å), and the NH2+ groups interact with nearby iodide anions (d(H⋅⋅⋅I)=2.633 and 2.698 Å).
Eutectic‐Based Ionic Liquids with Metal‐Containing Anions and Cations
Authors: Abbott Andrew P. , Barron John C. , Ryder Karl S. , Wilson David 
Published: May 2007

AbstractEutectic mixtures of zinc chloride and donor molecules such as urea and acetamide are described and it is proposed that these constitute a new class of ionic liquids. FAB‐MS analysis shows that the liquids are made up of metal‐containing anions and cations in which the donor is coordinated to the cation. Data on the viscosity, conductivity, density, phase behaviour and surface tension are presented and these are shown to be significantly different to other related ionic liquids that incorporate quaternary ammonium salts. The conductivity and viscosity are comparable with other ionic liquids and the data fit well to the Hole theory model recently proposed.
π–π Stacking versus Steric Effects in Stereoselectivity Control: Highly Diastereoselective Synthesis of syn‐1,2‐Diarylpropylamines
Authors: García Ruano José L. , Alemán José , Alonso Inés , Parra Alejandro , Marcos Vanesa , Aguirre José 
Published: May 2007

AbstractN‐Arylarylideneamines react with sulfinylbenzyl carbanions derived from 2‐(p‐tolylsulfinyl)toluenes (S)‐1 and (S)‐2, affording epimeric mixtures at C1 of 1,2‐diarylethyl‐ and 1,2‐diarylpropylamine derivatives. The sulfinyl group completely controls the configuration at C2 in the reactions of (S)‐2. The configuration at C1 depends on the electron density of the ring adjacent to the iminic carbon atom which is modulated by π–π stacking interactions with the ring joined to the carbanionic centre. The stereoselectivity was controlled by modifying the acceptor character of the arylideneamine ring with appropriate substituents, the formation of the highly selective (R) configuration at C1 being made possible by electron‐donating groups. N‐(2,4,6‐Trimethoxyphenyl)arylideneamines have been shown to be suitable starting materials for the preparation of (R)‐1,2‐diarylethyl‐ and (1R,2S)‐1,2‐diarylpropylamines (syn epimers) in a highly stereoselective manner.
Single‐Triggered AB6 Self‐Immolative Dendritic Amplifiers
Authors: Shamis Marina , Shabat Doron 
Published: May 2007

AbstractSelf‐immolative dendrimers are a unique class of molecules that are able to disassemble upon undergoing a specific triggering reaction through domino‐like fragmentations. We have designed and synthesized a novel AB6 self‐immolative dendritic adaptor that amplifies a single cleavage event into the release of six reporter units. The disassembly mechanism is based on a specifically triggered cleavage event followed by elimination of a cyclic urea derivative and six consecutive quinone methide eliminations. The system was disassembled under both organic and aqueous conditions by either chemical or enzymatic triggering. Various reporter molecules and triggering groups were introduced onto the dendritic adaptor to obtaining sensor molecules with enhanced properties for diagnostics and imaging.
Magnetic resonance imaging on an NMR spectrometer. An experiment for the physical chemistry laboratory
Authors: Steinmetz Wayne E. , Maher Cyrus R. 
Published: May 2007

AbstractWe converted a conventional Fourier‐transform NMR spectrometer into an MRI imager by installing a triple‐axis gradient probe and medical imaging software. This arrangement permits imaging of materials that fit into a 5‐mm NMR tube to a resolution of 0.05 mm or better. The experiment introduces the student to the physical principles underlying MRI such as gradients, spin echoes, multidimensional spectroscopy, and relaxation. Students employ a multi‐slice‐multi‐echo (MSME) method to image a biological specimen and measure the transverse relaxation time, T2, of water in selected regions of interest. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 133–139, 2007
GABA distribution in lamprey is phylogenetically conserved
Authors: Robertson Brita , Auclair François , Ménard Ariane , Grillner Sten , Dubuc Réjean 
Published: May 2007

AbstractThe localization of γ‐aminobutyric acid (GABA) has been well described in most classes of vertebrates but not in adult lampreys. The question if the GABA distribution is similar throughout the vertebrate subphylum is therefore still to be addressed. We here investigate two lamprey species, the sea lamprey,Petromyzon marinus, and the river lamprey,Lampetra fluviatilis, and compare the GABA pattern with that of other vertebrates. The present immunohistochemical study provides an anatomical basis for the general distribution and precise localization of GABAergic neurons in the adult lamprey forebrain and brainstem. GABA‐immunoreactive cells were organized in a virtually identical manner in the two species. They were found throughout the brain, with the following regions being of particular interest: the granular cell layer of the olfactory bulb, the nucleus of the anterior commissure, the septum, the lateral and medial pallia, the striatum, the nucleus of the postoptic commissure, the thalamus, the hypothalamus, and pretectal areas, the optic tectum, the torus semicircularis, the mesencephalic tegmentum, restricted regions of the rhombencephalic tegmentum, the octavolateral area, and the dorsal column nucleus. The GABA distribution found in cyclostomes is very similar to that of other classes of vertebrates, including mammals. Since the lamprey diverged from the main vertebrate line around 450 million years ago, this implies that already at that time the basic vertebrate plan for the GABA innervation in different parts of the brain had been developed. J. Comp. Neurol. 503:47–63, 2007. © 2007 Wiley‐Liss, Inc.
Cellular subtype distribution and developmental regulation of TRPC channel members in the mouse dorsal root ganglion
Authors: Elg Susanne , Marmigere Frederic , Mattsson Jan P. , Ernfors Patrik 
Published: May 2007

AbstractTransient receptor potential (TRP) channels play essential roles in sensory physiology and their expression in different classes of sensory neurons reflect distinct receptive properties of these neurons. While expression of the TRPV, TRPA, and to a certain degree TRPM classes of channels has been studied in sensory neurons, little is known about the expression and regulation of TRPC channels. In this study we examined the regulation of all TRPC members (TRPC1–C7) throughout embryonic and postnatal development of the dorsal root ganglion (DRG) and nodose ganglion (NG). In adult mice, mRNAs for all channels were present in the DRG, with TRPC1, 3, and 6 being the most abundant, TRPC2, C4, and C5 at lower levels, and TRPC7 at very low levels. While TRPC2 mRNAs were downregulated from high levels at embryonic (E) day 12 and E14 until adult, TRPC4, C5, and C7 expressions increased from E12 to peak levels at E18. TRPC1, C3, and C6, the most abundant TRPC channel mRNAs, increased progressively from E12 to adult. Expression and regulation of TRPC channels mRNAs in the NG were unexpectedly similar to the DRG. TRPC1 and C2 was expressed in the neurofilament‐200 (NF‐200)‐positive large size subclass of neurons, while TRPC3 mRNAs expression, which stained up to 35% of DRG neurons, was almost exclusively present in nonpeptidergic isolectin B4 (IB4)‐positive small size neurons that were largely TRPV1‐negative. Our results suggest important roles of the TRPC family of channels in sensory physiology of both nociceptive as well as nonnociceptive classes of neurons. J. Comp. Neurol. 503:35–46, 2007. © 2007 Wiley‐Liss, Inc.
Distribution and localization patterns of estrogen receptor‐β and insulin‐like growth factor‐1 receptors in neurons and glial cells of the female rat substantia nigra: Localization of ERβ and IGF‐1R in substantia nigra
Authors: Quesada Arnulfo , Romeo Horacio E. , Micevych Paul 
Published: May 2007

AbstractAlthough several studies have focused on the neuroprotective effects of estrogen (E2) on stroke, there have been tantalizing reports on the potential neuroprotective role of E2 in degenerative neuronal diseases such as Alzheimer's and Parkinson's (PD). In animal models of PD, E2 protects the nigrostriatal dopaminergic (DA) system against neurotoxins. However, little is known about the cellular and molecular mechanism(s) involved by which E2 elicits its neuroprotective effects on the nigrostriatal DA system. A preferred mechanism for neuroprotection is the interaction of E2 with specific neuroprotective growth factors and receptors. One such neuroprotective factor/receptor system is insulin‐like growth factor‐1 (IGF‐1). E2 neuroprotective effects in the substantia nigra (SN) DA system have been shown to be dependent on IGF‐1. To determine whether E2 also interacts with the IGF‐1 receptor (IGF‐1R) and to determine the cellular localization of estrogen receptor (ER) and IGF‐1R, we compared the distribution of ER and IGF‐1R in the SN. Stereological measurements revealed that 40% of the subpopulation of tyrosine hydroxylase‐immunoreactive (TH‐ir) SN pars compacta (SNpc) DA neurons are immunoreactive for estrogen receptor‐β (ERβ). No immunolabeling for ERα was observed. In situ hybridization and immunocytochemistry studies confirmed the expression of IGF‐1R mRNA and revealed that almost all TH‐ir SNpc DA neurons were immunoreactive for IGF‐1R, respectively. Moreover, one‐third of glial fibrillary acidic protein (GFAP‐ir) cells in the SN were ERβ‐ir, and 67% of GFAP‐ir cells expressed IGF‐1R‐ir. Therefore, the localization of ERβ and IGF‐1R on SNpc DA neurons and astrocytes suggests a modulatory role of E2 on IGF‐1R, and this modulation may affect neuroprotection. J. Comp. Neurol. 503:198–208, 2007. © 2007 Wiley‐Liss, Inc.
Identification of putative neuroblasts at the base of adult neurogenesis in the olfactory midbrain of the spiny lobster, Panulirus argus
Authors: Schmidt Manfred 
Published: May 2007

AbstractContinuous neurogenesis persists during adulthood in the olfactory midbrain of decapod crustaceans, including spiny lobsters, Panulirus argus. This encompasses generation of projection and local interneurons, whose somata are in the lateral soma cluster (LC) and medial soma cluster (MC), respectively. Both neuronal types originate from immediate precursors labeled by a single injection of BrdU and located in a small proliferation zone within each cluster. The aim of this study was to identify neuroblasts as a source of the dividing cells by multiple injections of BrdU over 2 days. All animals receiving multiple injections had one or a few ‘extra’ BrdU‐positive nuclei near the proliferation zones, and these nuclei were significantly larger than nuclei of neurons or BrdU‐positive cells in the proliferation zones. Since the defining morphological feature of neuroblasts in preadult neurogenesis in arthropods is being larger than their progeny, these large extra BrdU‐positive nuclei represent “putative adult neuroblasts.” Multiple BrdU‐injections revealed a clump of small cells enclosing the putative adult neuroblasts in LC and MC, and these cells shared morphological characteristics with newly identified putative glial cells in the soma clusters and perivascular cells in the walls of arterioles. These results on P. argus suggest that adult neurogenesis is based on one adult neuroblast per soma cluster, adult neurogenesis appears to be a continuation of embryonic and larval neurogenesis, and the newly identified clumps of cells surrounding the putative adult neuroblasts might provide them with specific microenvironments necessary for their unusual lifelong proliferative and self‐renewal capacity. J. Comp. Neurol. 503:64–84, 2007. © 2007 Wiley‐Liss, Inc.
Sensory and multisensory representations within the cat rostral suprasylvian cortex
Authors: Clemo H. Ruth , Allman Brian L. , Donlan M. Andrew , Meredith M. Alex 
Published: May 2007

AbstractBecause the posterior limb of the rostral suprasylvian sulcus (RSp) of the cat resides in close proximity to representations of the somatosensory, auditory, and visual modalities, the surrounding cortices would be expected to be a region where a high degree of multisensory convergence and integration is found. The present experiments tested this notion by using anatomical and electrophysiological methods. Tracer injections into somatosensory, auditory, and visual cortical areas almost all produced terminal labeling within the RSp, albeit at different locations and in different proportions. Inputs from somatosensory cortices primarily targeted the inner portion of the anterior RSp; inputs from auditory cortices generally filled the outer portion of the middle and posterior RSp; inputs from visual cortices terminated in the inner portion of the posterior RSp. These projections did not have sharp borders but often overlapped one another, thereby providing a substrate for multisensory convergence. Electrophysiological recordings confirmed this anatomical organization as well as identifying the presence of multisensory (bimodal) neurons in the areas of overlap between representations. Curiously, however, the proportion of bimodal neurons was only 24% of the neurons sampled in this region, and the majority of these did not show multisensory interactions when combined‐modality stimuli were presented. In summary, these experiments indicate that the RSp is primarily auditory in nature, but this representation could be further subdivided into an outer sulcal anterior auditory field (sAAF) and an inner field of the rostral suprasylvian sulcus (FRS). J. Comp. Neurol. 503:110–127, 2007. © 2007 Wiley‐Liss, Inc.
Corticotropin‐releasing hormone neurons in hypertensive patients are activated in the hypothalamus but not in the brainstem
Authors: Goncharuk Valeri D. , Buijs Ruud M. , Swaab Dick F. 
Published: May 2007

AbstractThe corticotrophin‐releasing hormone (CRH)‐expressing neurons were studied in the hypothalamus and brainstem of individuals who suffered from essential hypertension and had died due to acute myocardial infarction or brain hemorrhage. Healthy normotensive individuals who died in accidents made up the control group. In hypertensive patients we found extremely high expression of CRH in all parts of the hypothalamic paraventricular nucleus (Pa). In addition, CRH neuronal profiles were observed in the caudal hypothalamic area and dorsal parts of the extended amygdala. In the control group, CRH neurons were found only in the Pa and in much smaller numbers than in hypertensive patients. Also, in contrast to the controls, we found in hypertensives a very high number of CRH fibers running from the most rostral part of the Pa to the median eminence and innervating the caudal part of the suprachiasmatic nucleus (SCh). A quantitative evaluation showed that the area covered by CRH fibers in the SCh of hypertensives was about three times larger than that in the control SCh. Linear regression analysis demonstrated a negative correlation between the area of CRH fibers and the number of vasopressin (VP) or neurotensin (NT) neurons within the SCh. This relationship occurred particularly in hypertensive patients in whose SCh a larger CRH fiber area and a smaller number of VP or NT neurons were observed. We found a few CRH neuronal profiles and fibers in brainstem nuclei that are involved in cardiovascular regulation, but no apparent difference was observed between the control and hypertensive group. J. Comp. Neurol. 503:148–168, 2007. © 2007 Wiley‐Liss, Inc.
Levels of transient gap junctions between the retinal pigment epithelium and the neuroblastic retina are influenced by catecholamines and correlate with patterns of cell production
Authors: Tibber Marc S. , Becker David , Jeffery Glen 
Published: May 2007

AbstractRetinal mitosis takes place at the interface between the retinal pigment epithelium (RPE) and the neural retina. Multiple studies have highlighted the essential role that gap junction‐mediated communication plays in the regulation of retinal organogenesis. Here, the localization pattern and function of the gap junction protein connexin 43 were examined in vivo in the rat at the interface between the retina and RPE during the main phases of retinal cell production. Connexin 43 was expressed at this site from E15 onward, and levels were subsequently temporally regulated. When Cx43 protein levels were reduced experimentally, by using antisense oligodeoxynucleotides, mitotic activity in the retina decreased significantly. Conversely, in the hypopigmented eye elevated mitotic levels were associated with a significant increase of connexin 43. Both excess protein levels and elevated mitosis were corrected by the in vivo administration of L‐DOPA (a dopamine precursor and intermediary compound in the melanin synthesis pathway). These findings suggest that connexin 43‐mediated communication between the retina and RPE is essential for the correct pacing of retinal organogenesis. Furthermore, this pathway may be gated by levels of ocular catecholamines. J. Comp. Neurol. 503:128–134, 2007. © 2007 Wiley‐Liss, Inc.