bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monitoring 2‐D gel‐induced modifications of proteins by MALDI‐TOF mass spectrometry
Authors: Hamdan Mahmoud , Galvani Marina , Righetti Pier Giorgio 
Published: August 2002

Abstract

I.
Introduction
121

II.
Protein Alkylation by Acrylamide and Its N‐Substituted Monomers
122

III.
Protein Alkylation by Free Immobiline Chemicals
125

IV.
Site of Reaction
127

V.
Probing Protein Unfolding Through the Monitoring of Cys Alkylation
129

VI.
Protein Reactions with a Number of Gel Electrophoresis Crosslinkers
130

VII.
Do Such Modifications Manifest Themselves in Real‐Life Analyses?
134

VIII.
How Does Sample Preparation for 2‐D Gels Influence Certain Modifications?
136

IX.
What Are the Consequences of a Poor Sample Alkylation?
136

X.
Conclusions
138

Acknowledgments
139

References
139

In addition to more than 200 endogenously produced post‐translational modifications, a detailed analysis of 2‐D gel‐separated proteins must also consider other modifications that a protein can experience during various steps of its separation. This review describes the use of matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry to investigate some of these modifications, which can originate during sample preparation and/or during the separation phase. The analyses described were mostly conducted at pH 9–9.5, and yielded reliable information on stable adduct formation that involved protein‐bound amino acids and a number of gel components, including acrylamide derivatives, gel cross‐linkers, and Immobiline chemicals. The –SH group of Cys was found to be the prime target of such adducts; however, longer reaction times revealed the involvement of the ε‐NH2 of Lys. The same analysis revealed that the failure to achieve full reduction/alkylation prior to any electrophoretic step could result in protein–protein interaction, which could lead to a number of spurious spots in the final 2‐D map. The implications of these modifications on the MS analysis in particular and on proteome research in general are discussed. © 2001 John Wiley & Sons, Inc., Mass Spec Rev 20:121–141, 2001
Protease inhibitor–induced stabilization of p21waf1/cip1 and cell‐cycle arrest in chemical carcinogen–exposed mammary and lung cells†
Authors: Khan Qasim A. , Dipple Anthony , Anderson Lucy M. 
Published: August 2002

AbstractIn previous studies, we have shown that human breast and lung carcinoma cells and mouse nontransformed type II lung cells fail to undergo cell‐cycle arrest in G1 phase in response to treatment with hydrocarbon carcinogens but rather accumulate in the S phase with damaged DNA. This situation may lead to replication of DNA on a damaged template and enhance frequency of mutations. The mechanism of this G1 arrest failure was examined. Western immunoblot analyses of MCF7 human mammary cancer cells exposed to actinomycin D (used as a positive control for G1 cell‐cycle arrest) or hydrocarbon carcinogens revealed that while all of these chemicals caused an increase in p53, only trace levels of p21waf1/cip1 protein were observed in the hydrocarbon carcinogen‐treated samples. Similarly, in murine lung E10 type II cells, p53 but not p21waf1/cip1 protein increased in response to benzo[a]pyrene dihydrodiol epoxide. Treatment of either MCF7 mammary or E10 lung cells with the protease inhibitor calpain I resulted in increased levels of p21waf1/cip1 protein and enhancement of arrest of the cells in early phases of the cell cycle (G1 and early S phase). The results suggest that failure of cell‐cycle arrest in carcinogen‐treated mammary and lung cells is related to increased protease‐mediated degradation of p21waf1/cip1 and/or related regulatory proteins. Published 2002 Wiley‐Liss, Inc.
Inhibitory effect of glycolic acid on ultraviolet‐induced skin tumorigenesis in SKH‐1 hairless mice and its mechanism of action
Authors: Hong Jin Tae , Kim Eun Joung , Ahn Kwang Soo , Jung Kyoung Mi , Yun Yeo Pyo , Park Yong Keun , Lee Sun Hee 
Published: August 2002

AbstractGlycolic acid, an alpha‐hydroxy acid derived from fruit and milk sugars, has been used commonly as a cosmetic ingredient since it was discovered to have photoprotective and anti‐inflammatory effects and antioxidant effects on ultraviolet (UV)B–irradiated skin. Little is known, however, about the functional role of glycolic acid on UV‐induced skin tumorigenesis. In the present study, we examined the effect of glycolic acid on UV (UVA + UVB)–induced skin tumorigenesis and assessed several significant contributing factors in SKH‐1 hairless mice. Inbred hairless female mice (15 animals/group) were irradiated for 5 d/wk at a total dose of 74.85 J/cm2 UVA and 2.44 J/cm2 UVB for 22 wk. Glycolic acid was applied topically twice a week at a dose of 8 mg/cm2 immediately after UV irradiation. Glycolic acid reduced UV‐induced skin tumor development. The protective effect of glycolic acid was a 20% reduction of skin tumor incidence, a 55% reduction of tumor multiplicity (average number of tumors/mouse), and a 47% decrease in the number of large tumors (larger than 2 mm). Glycolic acid also delayed the first appearance of tumor formation by about 3 wk. The inhibitory effect of glycolic acid on UV‐induced tumor development was accompanied by decreased expression of the following UV‐induced cell‐cycle regulatory proteins: proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin E, and the associated subunits cyclin‐dependent kinase 2 (cdk2) and cdk4. In addition, the expression of p38 kinase, jun N‐terminal kinase (JNK), and mitogen‐activated protein kinase kinase (MEK) also was lower in UV + glycolic acid–treated skin compared with expression in UV‐irradiated skin. Moreover, transcription factors activator protein 1 (AP‐1) and nuclear factor κB (NF‐κB) activation was significantly lower in UV + glycolic acid–treated skin compared with activation in UV‐irradiated skin. These results show that glycolic acid reduced UV‐induced skin tumor development. The decreased expression of the cell‐cycle regulatory proteins PCNA, cyclin D1, cyclin E, cdk2, and cdk4 and the signal mediators JNK, p38 kinase, and MEK may play a significant role in the inhibitory effect of glycolic acid on UV‐induced skin tumor development. In addition, the inhibition of activation of transcription factors AP‐1 and NF‐κB could contribute significantly to the inhibitory effect of glycolic acid. © 2001 Wiley‐Liss, Inc.
Case report of pallido‐pyramidal disease with supplementary motor area involvement
Authors: Pradat Pierre‐François , Dupel‐Pottier Corinne , Lacomblez Lucette , Salachas François , Meininger Vincent , Lacomblez Lucette , Spelle Laurent , Bonnaud Isabelle , Ribeiro Marie Joao , Remy Philippe , Samson Yves 
Published: August 2002

AbstractAn C‐flumazenil positron emission tomography (PET) study in a patient with pallido‐pyramidal disease revealed a marked decrease in benzodiazepine‐receptor density in the precentral gyrus cortex and the mesial frontal cortex. We suggest that, in addition to dysfunction of basal ganglia‐dependent systems, degeneration of the supplementary motor area could also be involved in the patient's bradykinesia. © 2001 Movement Disorder Society.
Focal myopathy as a cause of anterocollis in Parkinsonism
Authors: Lava Neil S. , Factor Stewart A. 
Published: August 2002

AbstractWe present a patient with levodopa‐responsive Parkinsonism who developed disproportionate anterocollis over a period of 4 to 5 weeks. A neurological evaluation, including EMG and muscle biopsy, demonstrated the presence of a focal myopathy typical of the so‐called “dropped head syndrome” or “isolated neck extensor myopathy.” Parkinsonian patients presenting with disproportionate anterocollis should be evaluated for focal myopathy, as this may represent one possible cause.
Nonlinear sensory cortex response to simultaneous tactile stimuli in writer's cramp
Authors: Sanger Terence D. , Pascual‐Leone Alvaro , Tarsy Daniel , Schlaug Gottfried 
Published: August 2002

AbstractWriter's cramp is a task‐specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de‐differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities. © 2001 Movement Disorder Society
Binding interactions between peptides and proteins of the class II Major Histocompatibility Complex
Authors: McFarland Benjamin J. , Beeson Craig 
Published: August 2002

AbstractThe activation of helper T cells by peptides bound to proteins of the class II Major Histocompatibility Complex (MHC II) is pivotal to the initiation of an immune response. The primary functional requirement imposed on MHC II proteins is the ability to efficiently bind thousands of different peptides. Structurally, this is reflected in a unique architecture of binding interactions. The peptide is bound in an extended conformation within a groove on the membrane distal surface of the protein that is lined with several pockets that can accommodate peptide side‐chains. Conserved MHC II protein residues also form hydrogen bonds along the length of the peptide main‐chain. Here we review recent advances in the study of peptide‐MHC II protein reactions that have led to an enhanced understanding of binding energetics. These results demonstrate that peptide‐MHC II protein complexes achieve high affinity binding from the array of hydrogen bonds that are energetically segregated from the pocket interactions, which can then add to an intrinsic hydrogen bond‐mediated affinity. Thus, MHC II proteins are unlike antibodies, which utilize cooperativity among binding interactions to achieve high affinity and specificity. The significance of these observations is discussed within the context of possible mechanisms for the HLA‐DM protein that regulates peptide presentation in vivo and the design of non‐peptide molecules that can bind MHC II proteins and act as vaccines or immune modulators. © 2002 John Wiley & Sons, Inc. Med Res Rev, 22, No. 2, 168–203, 2002; DOI 10.1002/med.10006
Re‐animation of muscle flaps for improved function in dynamic myoplasty
Authors: Stremel Richard W. , Zonnevijlle Erik D.H. 
Published: August 2002

AbstractThe authors report on a series of experiments designed to produce a skeletal muscle contraction functional for dynamic myoplasties. Conventional stimulation techniques recruit all or most of the muscle fibers simultaneously and with maximal strength. This approach has limitations in free dynamic muscle flap transfers that require the muscle to contract immediately after transfer and before re‐innervation. Sequential stimulation of segments of the transferred muscle provides a means of producing non‐fatiguing contractions of the muscle in the presence or absence of innervation. The muscles studied were the canine gracilis, and all experiments were acute studies in anesthetized animals. Comparison of conventional and sequential segmental neuromuscular stimulation revealed an increase in muscle fatigue resistance and muscle blood flow with the new approach. This approach offers the opportunity for development of physiologically animated tissue and broadening the abilities of reconstructive surgeons in the repair of functional defects. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:281‐286 2001
Partial differential equations of chemotaxis and angiogenesis
Authors: Sleeman B. D. , Levine H. A. 
Published: August 2002

AbstractThe topic of this paper is concerned with an investigation of the qualitative properties of solutions to the following problem.Let Ω⊂Rn be a bounded domain with boundary ∂Ω.We seek solutions P,ω∈Rm+1 of the system

subject to the ‘no‐flux’ boundary condition

where n denotes the inward pointing normal to ∂Ω. To close the system we prescribe the initial conditions

In this system D is a constant diffusion coefficient, P is a population density and ω is a vector of nutrients or chemicals whose dynamics influences the movement of P.Notice here that the substances ω do not diffuse. If they do then the second equation of (1) is modified to

where d is a positive semi‐definite diagonal matrix. This more general system includes the so‐called Keller–Segel model of Biology ([1] Keller EF, Segel LA. Initiation of slime mold aggregation viewed as an instability. Journal of Theoretical Biology 1970; 26: 339–415). To motivate our study of system (1)–(3) we begin by outlining two themes. One basic to developmental biology and the other from angiogenesis. Copyright © 2001 John Wiley & Sons, Ltd.
Patch antenna size reduction by combining inductive loading and short‐points technique
Authors: Desclos L. , Mahe Y. , Reed S. , Poilasne G. , Toutain S. 
Published: August 2002

AbstractThe present letter concerns the reduction of the size of a patch antenna by combining two techniques. Inserting slots as inductive loading and making some short points in the middle of a patch excited originally in the TM001 mode permits us to obtain an overall reduction of 75%. This enables the development of antennas for several applications, especially in portable communication systems requiring small footprint devices. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 385–386, 2001.
Multinuclear magnetic resonance study of the structure and tautomerism of azide and iminophosphorane derivatives of chloropyridazines
Authors: Cmoch Piotr 
Published: August 2002

AbstractSome azido‐ and iminophosphorane derivatives of 3,6‐dichloro‐ and 3,4,5,6‐tetrachloropyridazine were synthesized and studied by means of NMR measurements. Based on multinuclear data (chemical shifts, coupling constants) for compounds containing the azide group, no potentially possible tetrazole–azide equilibrium can be observed, even under acidic conditions. An unusual substitution of a chlorine atom (in position 4) of tetrachloropyridazine in the reaction with hydrazine was demonstrated by NMR measurements of two newly synthesized compounds containing azido‐ and iminophosphorane groups. Using multinuclear magnetic resonance data, the sites of ethylation and protonation of azido‐ and iminophosphorane derivatives of chloropyridazines were established. In the case of the tetrazolopyridazines, ethylation occurs at the N1′ and N2′ atoms, whereas for monocyclic compounds it takes place at the N1 and/or N2 atoms of the pyridazine ring. Preferred sites of protonation are the N1′ atom of the tetrazole ring and the N1 atom of the pyridazine ring. Moreover, the structures of potassium salts of 6‐(3‐cyano‐1‐triazeno)tetrazolo[1,5‐b] pyridazine and its amido derivative were established using NMR data, especially 15N NMR chemical shifts. Copyright © 2002 John Wiley & Sons, Ltd.
An improved DEPT–HMQC sequence for high‐throughput NMR analysis
Authors: Spitzer Timothy , Sefler Andrea M. , Rutkowske Randy 
Published: August 2002

AbstractTwo new pulse sequences are presented for the acquisition of DEPT–HMQC spectra, based on the original experiment of Kessler et al. The new sequences employ modifications intended to make the experiment well suited for high‐throughput acquisition and automated analysis. The sequences use coherence selection with gradients to reduce artifacts and constant‐time evolution to suppress unwanted F1 modulation. In addition, the new sequences require fewer pulses than the original experiment, and perform well even when pulse lengths are slightly mis‐set. Copyright © 2001 John Wiley & Sons, Ltd.
Uterine‐embryonic interaction in pig: Activin, follistatin, and activin receptor II in uterus and embryo during early gestation
Authors: van de Pavert S.A. , Boerjan M.L. , Stroband H.W.J. , Taverne M.A.M. , van den Hurk R. 
Published: August 2002

AbstractThe mRNA expression patterns of activin βA and follistatin in the uterus and embryo, the mRNA expression of the activin receptor II in the embryo, and the localization in the uterus of the immunoreactive activin βA and the receptor II proteins in the uterus were examined at gestation days 7–12 after ovulation in pig. Activin was located predominantly at the mesometrial side of the uterus during all stages of pregnancy studied. Follistatin mRNA was absent in the uterus during these stages, suggesting that activin of uterine origin is not inhibited by intra‐uterine follistatin. The receptor was localized throughout the glandular and luminal epithelium of the uterus. In the embryo, activin was expressed predominantly in the epiblast before unfolding, but after unfolding of the epiblast activin expression shifted to the trophoblast. The expression pattern of follistatin mRNA was contrarily to that of activin, i.e., before unfolding predominantly in the trophoblast (days 8–9), and shifted to the epiblast at day 10. During streak stages, follistatin was detected in the node and primitive streak. Activin receptor II mRNA was first detected at day 8 in the embryoblast. At day 11, it was expressed in trophoblast cells near the epiblast, and in the first ingressing mesoderm cells. During the streak stages, it was expressed predominantly in the trophoblast. The presence of activin and its receptor in uterine epithelium and early embryonic tissues indicate that both embryonic and uterine activin are involved in intra‐uterine processes, such as attachment and early embryonic development. Mol. Reprod. Dev. 59: 390–399, 2001. © 2001 Wiley‐Liss, Inc.
Supporting positive sibling relationships during childhood
Authors: Stoneman Zolinda 
Published: August 2002

AbstractThis paper reviews the research literature focusing on the interpersonal relationships between siblings when one child has a disability. Descriptive findings are presented that compare and contrast sibling warmth and positivity, engagement, and conflict in sibling pairs with and without a child with a disability. The social roles assumed by siblings are examined, as are developmental changes in role relationships. Research on the development of the sibling relationship in the family context is reviewed, as are findings concerning the effects of parent differential attention on the quality of the sibling relationship. MRDD Research Reviews 7:134–142, 2001. © 2001 Wiley‐Liss, Inc.
In vivo GABA editing using a novel doubly selective multiple quantum filter
Authors: Shen Jun , Rothman Douglas L. , Brown Peter 
Published: August 2002

AbstractA novel multiple quantum filtering method is proposed that uses a doubly selective pulse termed Delays Alternating with Nutations for Tailored Excitation (DANTE) for multiple quantum preparation. This method selectively prepares GABA‐3 and GABA‐4 into a multiple quantum state and suppresses all other resonances at 3.0 ppm in each single scan. Phantom tests demonstrated excellent GABA signal retention and complete suppression of overlapping metabolites. It is shown using numerical simulations that overlapping macromolecules are suppressed because the frequency of the first upfield 2π rotation of the doubly selective DANTE pulse coincides with that of the macromolecules at 1.72 ppm. Excellent suppression of overlapping macromolecules was demonstrated in vivo. Using this method the concentration of GABA in the occipital lobe of healthy volunteers was measured to be 1.21 ± 0.28 μmol/mL (mean ± SD, N = 9). Magn Reson Med 47:447–454, 2002. © 2002 Wiley‐Liss, Inc.
Inverse T2 contrast at 1.5 Tesla between gray matter and white matter in the occipital lobe of normal adult human brain
Authors: Zhou Jinyuan , Golay Xavier , van Zijl Peter C.M. , Silvennoinen M. Johanna , Kauppinen Risto , Pekar James , Kraut Michael 
Published: August 2002

AbstractT2 of cortical gray matter is generally assumed to be longer than that of white matter. It is shown here that this is not the case in the occipital lobe, but that this effect is often obscured at lower resolution and concealed in standard T2‐weighted images. Using a high‐resolution (1 × 1.3 × 2 mm3) segmented EPI Carr‐Purcell‐Meiboom‐Gill sequence, T2 relaxation times of the brain were measured at 1.5 T for eight healthy adult volunteers. The average T2 values of cortical gray and white matter were found to be 88± 2 and 84± 3 msec in the frontal lobe, 84± 2 and 83± 3 msec in the parietal lobe, and 79± 1 and 87 ± 3 msec in the occipital lobe, respectively. This unexpected occipital T2 contrast between gray and white matter is attributed to regional differences in iron concentration. Magn Reson Med 46:401–406, 2001. © 2001 Wiley‐Liss, Inc.
Obturator neuropathy: Causes and outcome
Authors: Sorenson Eric J. , Chen Joseph J. , Daube Jasper R. 
Published: August 2002

AbstractTo study causes of obturator neuropathy and to correlate them with outcome, we retrospectively studied patients seen at the Mayo Clinic electromyography (EMG) laboratory from 1975 through 1999 with a diagnosis of obturator neuropathy. Twenty‐two patients with obturator neuropathy were identified. The clinical outcome of patients with acute obturator neuropathy treated conservatively was good regardless of etiology or severity. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Longitudinal study of functional spinal alpha motor neuron loss in amyotrophic lateral sclerosis
Authors: Arasaki K. , Kato Y. , Hyodo A. , Ushijima R. , Tamaki M. 
Published: August 2002

AbstractUsing a microstimulation technique for obtaining motor unit number estimates (MUNEs) of the hypothenar and extensor digitorum brevis (EDB) muscles, we performed a longitudinal study on the natural course of change in the clinical rating scale (Appel score) and of loss of functional spinal alpha motor neurons in amyotrophic lateral sclerosis. The Appel score increased to about 150% of normal at 12 months after onset, about 225% at 18 months after onset, and about 370% at 24 months after onset. By contrast, MUNEs decreased to about 27% of normal at 12 months after onset, about 12% at 18 months after onset, and about 5% at 24 months after onset. The relative merits of these different approaches in detecting changes in the disease process in its early phase are discussed. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002