bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of steroidogenic factor 1 and aromatase in temperature‐dependent sex determination in the red‐eared slider turtle
Authors: Crews David , Fleming Alice , Willingham Emily , Baldwin Ryan , Skipper James K.
Published: August 2002

Red‐eared slider turtles are genetically bipotential for sex determination. In this species, as in many other reptiles, incubation temperature of the egg determines gonadal sex. At higher incubation temperatures females are produced and increasing temperature appears to increase estrogen production in the embryonic brain. Treatment of eggs incubating at a male‐producing temperature with exogenous estrogen causes ovaries to form. At a female‐biased incubation temperature, prevention of estrogen biosynthesis or administration of nonaromatizable androgens results in the development of testes. In mammals, steroidogenic factor 1 (SF‐1) regulates most genes required for estrogen biosynthesis, including aromatase. In both mammals and red‐eared sliders, SF‐1 is differentially expressed in males and females during gonadogenesis. We have examined both SF‐1 gene expression and aromatase activity in embryos incubating at different temperatures and after manipulation to change the course of gonadal development. Our findings indicate a central role for SF‐1 in enacting the effect of estrogen. Estrogen treatment directly or indirectly downregulates SF‐1 and, ultimately, causes development of females. The inhibition of estrogen results in upregulation of SF‐1 and male hatchlings. Thus, SF‐1 may lie at the center of one molecular crossroad in male versus female differentiation of the red‐eared slider. J. Exp. Zool. 290:597–606, 2001. © 2001 Wiley‐Liss, Inc.
Transcription pattern of ribosomal protein L26 during anoxia exposure in Littorina littorea
Authors: Larade Kevin , Nimigan Andre , Storey Kenneth B.
Published: August 2002

Differential screening of a hepatopancreas cDNA library derived from the marine snail Littorina littorea yielded a 421‐bp clone coding for ribosomal protein L26 that was up‐regulated during anoxia exposure. The deduced amino acid sequence, containing 144 residues with a predicted molecular weight of 17 kDa, showed 80% amino acid sequence identity to the mammalian ribosomal protein L26. Analysis of hepatopancreas and foot muscle samples from a time course of anoxia exposure showed a maximal transcript increase of 4‐ and 3‐fold after 96 hr and 48 hr, respectively, relative to normoxic animals, with a subsequent decrease in transcript levels during normoxic recovery. Nuclear run‐off assays confirmed the observed transcriptional up‐regulation of L26 during anoxia. Organ culture experiments were performed to determine a possible pathway of up‐regulation of L26, with data indicating a putative role for cGMP in signal transduction. The transcriptional up‐regulation of L26 during anoxia may stabilize the existing mRNA pool, via a possible cGMP‐mediated signaling cascade, until oxygen reappears and protein synthesis resumes. J. Exp. Zool. 290:759–768, 2001. © 2001 Wiley‐Liss, Inc.
ICTs in development—who benefits? Use of geographic information systems on the Cato Manor Development project, South Africa
Authors: Odendaal Nancy
Published: August 2002

The focus on the digital divide raises important questions with regards to the global impact of information technology. Technical inequalities are, however, often embedded in the development project where access to technological knowledge becomes a determining factor in the development process. This paper aims to uncover the use of geographic information systems (GIS) on the Cato Manor Development Project in Durban, South Africa. The focus will be on an instant where the legitimacy of the project was challenged by former residents, removed from the area during the Apartheid era, and the role of information technology in resolving that conflict. The paper will show that GIS is not necessarily a value‐free tool, but can influence development decisions contrary to the expectations of those affected by it. Copyright © 2002 John Wiley & Sons, Ltd.
Vertebrate limb development and possible clues to diversity in limb form
Authors: Tickle Cheryll
Published: August 2002

Chick embryos are good models for vertebrate development. The principles that underlie chick wing development have been discovered and there is increasing knowledge about the molecules involved. The importance of identifying molecules is that this provides a direct link to understanding the genetic basis of diversity in form. Chick wing development will be compared with limb development in other vertebrates. Possible mechanisms that could lead to variations in form, including limb reductions and limblessness, differences between fore‐ and hindlimbs, limb proportions, and interdigital webbing can be suggested. J. Morphol. 252:29–37, 2002. © 2002 Wiley‐Liss, Inc.
Larval and metamorphic development of the foregut and proboscis in the caenogastropod Marsenina (Lamellaria) stearnsii
Authors: Page L.R.
Published: August 2002

The specialized, postmetamorphic feeding structures of predatory caenogastropods evolved by changes to an ancestral caenogastropod developmental program that generated a planktotrophic larval stage followed by a herbivorous postmetamorphic stage. As part of a program of comparative studies aimed at reconstructing these developmental changes, I studied the development of the postmetamorphic feeding system of Marsenina stearnsii using histological sections for light microscopy and scanning and transmission electron microscopy. The feeding system of this species has two very different designs during ontogeny. The larval system uses ciliary effectors to capture and ingest microalgae, whereas the juvenile/adult system includes a proboscis, jaws, and radular apparatus for predation on ascidian zooids. The postmetamorphic foregut begins to develop during the early larval phase, but the anlagen does not interfere with larval feeding because it develops as an increasingly elaborate outpocketing from the ventral wall of the larval esophagus. At metamorphosis, an opening is created in the anterior tip of the prospective, postmetamorphic buccal cavity and the margins of this opening anneal with the metamorphically remodeled lips of the larval mouth. This process exposes the jaws, which differentiate within the buccal cavity prior to metamorphosis. As a working hypothesis, I suggest that rupture of the buccal cavity to the outside at metamorphosis was selected as a mechanism to allow precocious development of jaws in species where jaws enhanced feeding performance by young juveniles. The larval esophagus of M. stearnsii appears to be completely destroyed at metamorphosis. Larval esophageal cells have distinctive apical characteristics (cilia, blebbed microvilli, stacks of lamellae within the glycocalyx) and no cells having this signature persist through metamorphosis. Development of the proboscis and proboscis sac, which begins prior to metamorphosis, conforms to previous descriptions of pleurembolic proboscis development, although an acrembolic proboscis has been ascribed to members of the Lamellaroidea. J. Morphol. 252:202–217, 2002. © 2002 Wiley‐Liss, Inc.
Whole brain apparent diffusion coefficient histogram: A new tool for evaluation of leukoaraiosis
Authors: Mascalchi Mario , Tessa Carlo , Moretti Marco , Della Nave Riccardo , Boddi Vieri , Martini Sara , Inzitari Domenico , Villari Natale
Published: August 2002

Purpose

To test whole brain apparent diffusion coefficient histogram analysis as an alternative approach to visual score for the assessment of leukoaraiosis (LA).

Materials and Methods

T2 and diffusion weighted images were obtained in 15 elderly patients. LA extension was assessed on T2 weighted images by two observers using a semiquantitative visual score. Apparent diffusion coefficient (ADC) maps of the entire brain were generated and, after exclusion of the skull with manual tracing and of the cerebrospinal fluid (CSF) by application of a threshold value, whole brain (WB)‐ADC histogram was obtained. Moreover, a brain volume index (BVI) was calculated on ADC maps as (intracranial volume – CSF volume) /intracranial volume.

Results

The kappa inter‐observer agreement for LA scoring was 0.69. Manual segmentation of the skull showed a mean inter‐operator coefficient of variation below 3%. The median value of whole brain ADC histogram directly correlated with LA extension (P = 0.013). Moreover a significant inverse correlation (P = 0.002) was found between WB‐ADC median value and BVI.

Conclusion

WB‐ADC histogram is a reproducible alternative tool for assessing LA extension and severity. J. Magn. Reson. Imaging 2002;15:144–148. © 2002 Wiley‐Liss, Inc.
Utilizing SENSE to achieve lower station sub‐millimeter isotropic resolution and minimal venous enhancement in peripheral MR angiography
Authors: Maki Jeffrey H. , Wilson Gregory J. , Eubank William B. , Hoogeveen Romhild M.
Published: August 2002

Purpose

To use the parallel imaging technique, sensitivity encoding (SENSE), to increase spatial resolution and decrease venous contamination in peripheral magnetic resonance angiography (MRA).

Materials and Methods

Moving table, single‐bolus peripheral contrast‐enchanced (CE) ‐MRA was performed on nine patients. Manual table movement combined with SENSE in the upper station allowed for more rapid overall scan coverage such that acquisition of the lower station began 34 seconds after aortic contrast arrival. True sub‐ millimeter isotropic resolution was achieved in the lower station.

Results

Diagnostic MR angiograms of all three stations were obtained in all nine patients. Venous enhancement did not confound interpretation in any case. Sub‐millimeter lower station resolution provided excellent vascular detail.

Conclusion

Decreased delay time between upper and lower station acquisition in single bolus peripheral MR angiograms, now possible using parallel imaging techniques, combined with lower station sub‐millimeter resolution may decrease venous contamination and increase overall interpretability, thus increasing clinical acceptance of peripheral MRA. J. Magn. Reson. Imaging 2002;15:484–491. Published 2002 Wiley‐Liss, Inc.
The OptiMARK clinical development program: Summary of safety data
Authors: Brown Jeffrey J. , Kristy Rita M. , Stevens Gary R. , Pierro Joseph A.
Published: August 2002

Purpose

To describe and summarize the safety data from the OptiMARK clinical development program.

Materials and Methods

In the 18 clinical studies comprising the clinical program, doses ranging from 0.1 to 0.7 mmol/kg were administered to healthy adult volunteers, patients with hepatic or renal impairment, and patients with confirmed or highly suspected central nervous system (CNS), liver, breast, vascular, bone, or soft tissue pathologies. A total of 2038 injections of OptiMARK, Magnevist, or placebo were administered to 1684 subjects. Safety assessments were performed at appropriate intervals during all Phase 1, 2, and 3 studies.

Results

Of the 1684 subjects exposed to a study drug or placebo in the clinical development program, 646 subjects experienced 1293 adverse events. Thirty‐one percent of the OptiMARK injections were associated with an adverse event. In comparison, 35% of Magnevist injections and 48% of placebo injections were associated with at least one adverse event.

Conclusions

OptiMARK was safe and well‐tolerated with a safety profile similar to that of Magnevist. J. Magn. Reson. Imaging 2002;15:446–455. © 2002 Wiley‐Liss, Inc.
Nonuniform flow dynamics in the aorta of normal children: A simplified approach to measurement using magnetic resonance velocity mapping
Authors: Fogel Mark A. , Weinberg Paul M. , Haselgrove John
Published: August 2002

Purpose

To determine regional flow dynamics in the normal aorta (Ao) in children. Understanding flow dynamics in children is important in cardiovascular energetics, in designing improved aortic reconstructions by crafting the surgery to mimic normal aortic flow, and in Doppler flow calculations.The objective of this study was to determine regional flow dynamics in the normal Ao in children.

Materials and Methods

We performed magnetic resonance velocity mapping on 13 subjects (ages 7.2 ± 6.2 years) with normal Aos to determine flow dynamics in four equal quadrants in the ascending (AAo) and descending aorta (DAo) aligned along the long axis of the Ao. Statistical significance was set at P < .05.

Results

In the AAo, the left posterior quadrant displayed significantly less blood flow (16% ± 5%) than the other quadrants (26–29%) over the cardiac cycle. In the DAo, both anterior quadrants carried significantly less blood flow (20% and 21%) than the posterior quadrants (27% and 32%). At maximum flow (15% ± 5% into the cardiac cycle for the AAo; 27% ± 15% for the DAo), there was significantly more flow in the right posterior quadrant (28% ± 2%) than other quadrants (22–23%) in the AAo. In the DAo, both posterior quadrants had significantly higher flow rates (27% and 30%) than the anterior quadrants (21% and 22%). Maximum velocity in both the AAo and the DAo occurred in the left posterior quadrant in 10/13 at 16–24% into the cardiac cycle. At end‐systole, a short flow reversal was noted in the posterior quadrants in the AAo in 11/13; in the DAo, this occurred in the anterior quadrants in 10/13.

Conclusion

Flow dynamics in the normal Ao in children are not symmetrical; the flow distributions are asymmetric in both the AAo and the DAo throughout systole, including flow reversal related to the dicrotic notch. These results may help improve Ao surgery. J. Magn. Reson. Imaging 2002;15:672–678. © 2002 Wiley‐Liss, Inc.
Year 2000 status of MRI in Mexico
Authors: Rodríguez A. , Rojas R. , Barrios F.A.
Published: August 2002

The development of clinical magnetic resonance imaging in Mexico has followed a different course from that in the U.S. and Europe. The first clinical unit was installed in Mexico in the late 1980s at the very beginning of clinical applications worldwide. Since then, installations have proceeded at a sedate pace that now brings the installed total to 66 imagers. The largest fraction of these units (28, or 42%) is in Mexico City, with a broad distribution across the remaining 23 Mexican states. There is a noticeable increase of the number of units (20, or 30%) in the states bordering the U.S., while the states bordering nations to the south have no units. More than half the units (38, or 58%) are 0.5 T units, while a further 35% are 1.0 T or higher. Slower addition of units in Mexico relative to the U.S. is attributed to the higher fraction of public‐funded hospitals and the inherent conservatism of such institutions when considering new technologies. Present public planning for health care development suggests that the coming decade will see more rapid installation of units to meet growing demand in Mexico for the latest medical technology. Experience over the past two decades indicates the need for more systematic training of technical and clinical personnel to implement these additions. The National University (Universidad Nacional Autónoma de México (UNAM) and the Metropolitan University (Universidad Autónoma Metropolitana (UAM) are collaborating with diverse clinical facilities to create such a program. J. Magn. Reson. Imaging 2001;13:813–817. © 2001 Wiley‐Liss, Inc.
Localization and biopsy of breast lesions by magnetic resonance imaging guidance
Authors: Helbich Thomas H.
Published: August 2002

Contrast‐enhanced MRI of the breast has proved to be a valuable tool in the detection and work‐up of breast lesions. Most of these lesions are small and not visible by other imaging modalities, such as mammography or US. Thus, only MR‐guided preoperative localization techniques or MR‐guided percutaneous biopsy can provide a histologic work‐up of such lesions. MR‐guided preoperative localization seems to be a well‐established procedure. However, MR‐guided biopsy is still problematic. Although prototypical biopsy systems have been developed, considerable progress is still required. Problems exist with MR‐guided biopsy due to severe needle artifacts and tissue shift during the intervention. Thus, needle biopsy currently is not recommended for lesions smaller than 10 mm. This work reviews current techniques for MR‐guided preoperative localization and percutaneous biopsy in breast lesions. The diagnostic accuracy achievable with these techniques will be discussed, as well as the potential for new research opportunities and directions. J. Magn. Reson. Imaging 2001;13:903–911. © 2001 Wiley‐Liss, Inc.
Discrimination between pentose oligosaccharides containing D‐xylopyranose or L‐arabinofuranose as non‐reducing terminal residue using fast atom bombardment mass spectrometry
Authors: Kováčik Vladimír , Pätoprstý Vladimír , Hirsch Ján
Published: August 2002

Collisional‐induced dissociation (CID) mass spectra of the [M + H]+ and [M − H]− ions obtained under fast atom bombardment conditions of a number of methyl glycoside di‐, tri‐ and tetrasaccharides, containing D‐xylopyranosyl and/or L‐arabinofuranosyl residues at the non‐reducing terminus, do not provide information about their ring size. This information could only be obtained from a careful comparison of the intensity ratio of the [M + Na − 90]+ and [M + Na − 104]+ ions (0,2Xt/1,5Xt) in the high‐energy CID spectra of the sodium‐cationized di‐, tri‐ and probably also tetrasaccharide compounds. Copyright © 2001 John Wiley & Sons, Ltd.
On‐line coupling of hollow fiber membranes with electrospray ionization mass spectrometry for continuous affinity selection, concentration and identification of small‐molecule libraries
Authors: Jiang Yun , Lee Cheng S.
Published: August 2002

Combinatorial chemistry has been widely employed in the pharmaceutical industry in the effort towards drug discovery. Rapid and sensitive screening of lead candidates among library compounds has thus imposed significant analytical challenges in recent years. This work involved the development of a continuous affinity capture and concentration system, providing cost‐effective and structural analysis of drug candidates in a flow‐through format. The system combines the strengths of a hollow fiber dialysis membrane of ease and speed of purification and concentration with the specificity of affinity interactions in solution. The complexes between the lead compounds and the affinity binding proteins are separated from other chemical components inside a dialysis hollow fiber as the result of their differences in size. The affinity complexes are further concentrated inside a second dialysis fiber. The concentrated drug candidates are liberated from the binding proteins in a microdialysis junction and can be directly identified using electrospray ionization mass spectrometry. Two model systems, including human serum albumin–warfarin‐related compounds and anti‐phenobarbital antibody–barbiturates, were employed for mechanistic studies of dialysis versus dissociation kinetics and competitive selection of drug candidates according to their binding strengths. Copyright © 2001 John Wiley & Sons, Ltd.
Primary and secondary kinetic isotope effects in proton (H+/D+) and chloronium ion (35Cl+/37Cl+) affinities
Authors: Gozzo Fábio Cesar , Eberlin Marcos N.
Published: August 2002

The Cooks' kinetic method and tandem‐in‐space pentaquadrupole QqQqQ mass spectrometry were used to measure primary and secondary kinetic isotope effects (KIEs) in H+ and Cl+ (X+) affinity for a series of A/A′ isotopomeric pairs. Gaseous, isotopomeric, and loosely bound dimers [A···X+···A′] were formed in combinations in which X = H+, D+, 35Cl+ or 37Cl+ and A/A′ = acetonitrile/acetonitrile − d3, acetonitrile/acetonitrile‐15N, acetonitrile‐d3/acetonitrile‐15N, acetone/acetone‐d6, acetone/acetone‐18O, acetone‐d6/acetone‐18O, pyridine/pyridine‐d5, pyridine/pyridine‐15N, pyridine‐d5/pyridine‐15N, or 3‐(35Cl)chloropyridine/3‐(37Cl)chloropyridine. Under nearly the same experimental conditions, the dimers were mass‐selected and then dissociated by low‐energy collisions with argon, yielding AX+ and A′X+ as the fragment ions. KIEs were measured from the changes in ion affinities of the neutrals (ΔX+) as estimated by the AX+/A′X+ abundance ratios. Using [A···H+(D+)···A′] and [A···35Cl+(37Cl+)···A′] dimers and by comparing their extent of dissociation under nearly identical collision‐induced dissociation conditions, the kinetic method was also applied, for the first time, to measure primary KIEs of the central ion as well as their influence on secondary KIEs. Becke3LYP/6‐311++G(2df,2p) calculations were found to provide Δ(ΔZPE)s for the competitive dissociation reactions that accurately predict the nature (normal or inverse) of the measured KIEs. Copyright © 2001 John Wiley & Sons, Ltd.
Products, rate constants and mechanisms of gas‐phase reactions of CX3+, CX2+, CX+ (X = F and/or Cl) and Cl+ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane
Authors: Marotta Ester , Paradisi Cristina
Published: August 2002

The gas‐phase ion chemistry of 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane was investigated with an ion trap mass spectrometer. Following electron ionization both compounds (M) fragment to [M − Cl]+, CX3+, CX2+, CX+ (X = F and/or Cl) and Cl+. The reactivity of each of these fragments towards their neutral precursors was studied to obtain product and kinetic data. Whereas [M − Cl]+, CCl3+ and CCl2F+ cations are unreactive under the experimental conditions used, all other species react via halide abstraction to give [M − Cl]+ and, to a far lesser extent, [M − F]+. In addition, CX2+ ions form CClX2+ in a process which formally amounts to chlorine atom abstraction, but more likely involves chloride ion abstraction followed by charge transfer. CX+ ions also form minor amounts of CX3+ product ions, possibly via chloride abstraction followed by or concerted with dihalocarbene elimination from the (incipient) [M − Cl]+ ion. Trivalent carbenium ions are less reactive than divalent species, which in turn are less reactive than the monovalent ions (reaction efficiencies are given in parentheses): CF3+(0.70) < CF2+(0.78) < CF+(0.96). More interestingly, within each family of ions reactivity increases with the number of fluorine substituents (e.g. CF2+ > CFCl+ > CCl2+ and CF+ > CCl+), i.e. reactivity increases with the ion thermochemical stability, as measured by available standard free enthalpies of formation. Evaluation of the energetics involved shows that reactions are largely driven by the stability of the neutrals more than of the ions. Finally, the products observed in the reaction of Cl+ are attributed to ionization of the neutral via charge transfer and fragmentation. Copyright © 2001 John Wiley & Sons, Ltd.
Phase I metabolism of ganstigmine. Rat, dog, monkey and human liver microsomal extracts investigated by liquid chromatography electrospray tandem mass spectrometry
Authors: Silvia Catinella , Nicola Pelizzi , Paola Puccini , Silvia Marchetti , Margherita Zanol , Daniela Acerbi , Paolo Ventura
Published: August 2002

Ganstigmine, a new acetylcholinesterase inhibitor, was incubated with rat liver microsomes and the resulting metabolites were identified by high‐performance liquid chromatographic/mass spectrometric (HPLC/MS) and HPLC/MS/MS analyses. The results showed the formation of eight main metabolites, among which geneseroline and molecules corresponding to mono‐hydroxylated, demethylated and reduced ganstigmine. The metabolic profile drawn for humans, dog and monkey showed a pattern very similar to that of rat: only in the case of liver dog microsomes higher amounts of geneseroline and of a metabolite identified as demethylated and reduced drug were detected. Copyright © 2001 John Wiley & Sons, Ltd.
Structural characterization of hexoses and pentoses using lead cationization. An electrospray ionization and tandem mass spectrometric study
Authors: Salpin Jean‐Yves , Tortajada Jeanine
Published: August 2002

The analytical potential of the complexation of isomeric underivatized hexoses (D‐glucose, D‐galactose, D‐mannose, D‐talose, D‐fructose), methylglycosides (1‐O‐methyl‐α‐D‐glucose and 1‐O‐methyl‐β‐D‐glucose) and pentoses (D‐ribose, D‐xylose, D‐arabinose and D‐lyxose) by Pb2+ ions, was investigated by electrospray ionization and tandem mass spectrometry (MS/MS). Pb2+ ions react mainly with monosaccharides by proton abstraction to generate [Pb(monosaccharide)m − H]+ ions (m = 1–3). At low cone voltage, a less abundant series of doubly charged ions of general formula [Pb(monosaccharide)n]2+ is also observed. The maximum number n of monosaccharides surrounding a single Pb2+ ion depends on the metal : monosaccharide ratio. Our study shows that MS/MS experiments have to be performed to differentiate Pb2+‐coordinated monosaccharides. Upon collision, [Pb(monosaccharide) − H]+ species mainly dissociate according to cross‐ring cleavages, leading to the elimination of CnH2nOn neutrals. The various fragmentation processes observed allow the C(1), C(2) and C(4) stereocenters of aldohexoses to be characterized, and also a clear distinction aldoses and fructose. Furthermore, careful analysis of tandem mass spectra also leads to successful aldopentose distinction. Lead cationization combined with MS/MS therefore appears particularly useful to identify underivatized monosaccharides. Copyright © 2002 John Wiley & Sons, Ltd.
Substituent effect and multisite protonation in the fragmentation of alkyl benzoates
Authors: Denekamp Chagit , Stanger Amnon
Published: August 2002

The dissociation of protonated alkyl benzoates (para H, CN, OMe and NO2) into protonated benzoic acids and alkyl cations was studied in the gas phase. It was found that the product ratio depends on the substituent at the para position of the phenyl ring. The substituent effect is probably the result of the formation of an ion–neutral complex intermediate that decomposes to an ion and a neutral, according to the relative proton affinities of the two moieties. The experimental results and theoretical calculations indicate that the favored protonation site in these compounds is the ester's carbonyl and that proton transfer from the phenyl ring to the ester group is very likely to occur under chemical ionization conditions. It is most probable that the carbonyl protonated form is a common intermediate in the fragmentation process, regardless of the protonation site. Copyright © 2002 John Wiley & Sons, Ltd.
Fragmentation characteristics of peptide–metal ion adducts under matrix‐assisted laser desorption/ionization post‐source decay time‐of‐flight mass spectrometric conditions
Authors: Jayawardene Dhammika , Dass Chhabil
Published: August 2002

Fragmentation reactions of sodium‐cationized enkephalin peptides generated by matrix‐assisted laser desorption/ionization were studied using post‐source decay (PSD) with a reflectron time‐of‐flight mass spectrometer. Several matrices and analyte–matrix sample preparation methods were evaluated for high‐intensity ion currents that could last for the entire PSD analysis. A triple dried‐droplet sample preparation procedure with 2,5‐dihydroxybenzoic acid as the matrix was found to yield abundant longer‐lasting ion signals of the peptide–Na+ ion adducts. The principal decay product of these adduct ions is the [bn−1 + Na + OH]+ ion, which provides an unambiguous identification of the C‐terminal residue of a peptide. In some peptides, the loss of a second residue from the C‐terminus is also observed. No other sequence‐specific ions were observed. Copyright © 2002 John Wiley & Sons, Ltd.
Histopathologic impact of TT virus infection on the liver of type C chronic hepatitis and liver cirrhosis in Japan
Authors: Moriyama Mitsuhiko , Matsumura Hiroshi , Shimizu Toshihiro , Shioda Atsuo , Kaneko Miki , Miyazawa Kouji , Miyata Hajime , Tanaka Naohide , Uchida Toshikazu , Arakawa Yasuyuki
Published: August 2002

The present investigation compared the histological findings in the liver of chronic hepatitis C patients who were or were not co‐infected with TT virus (TTV) to determine the histological and clinical characteristics of TTV infection. One hundred eighty patients with chronic hepatitis or liver cirrhosis type C were included in this study. Serum samples were tested for the presence of TTV DNA by a nested polymerase chain reaction. The liver biopsy specimen of each patient was examined, and scores were assigned to indicate the severity of each of the following features: inflammatory cell infiltration in the periportal, parenchymal, and portal areas; fibrous stage; lymphoid reaction in the portal area; portal sclerotic change; perivenular fibrosis; pericellular fibrosis; damage of bile duct; and irregular regeneration of hepatocytes. Sixty‐four (34.4%) of the 180 patients were positive for TTV DNA. The histological features of the liver and the blood biochemical parameters of the TTV DNA‐positive and TTV DNA‐negative patients, did not differ significantly except for the score of irregular regeneration (IR) of hepatocytes. Among those in the F4 stage of fibrosis, the score of IR of the TTV DNA‐positive patients was significantly higher than that of the TTV DNA‐negative patients. In conclusion, chronic TTV infection does not modify the biochemical features of chronic hepatitis type C patients. TTV may be a risk factor, however, for the development of hepatocellular carcinoma in patients with type C liver disease in the F4 stage. J. Med. Virol. 64:74–81, 2001. © 2001 Wiley‐Liss, Inc.
Isolated anti‐HBc in chronic hepatitis C predicts a poor response to interferon treatment
Authors: Sagnelli Evangelista , Coppola Nicola , Scolastico Carlo , Mogavero Anna Rita , Stanzione Maria , Filippini Pietro , Felaco Francesca Maria , Piccinino Felice
Published: August 2002

The sustained response to interferon‐α treatment was evaluated in 147 anti‐HCV/HCV‐RNA‐positive, HBsAg‐negative, chronic hepatitis patients, according to HCV genotypes and the presence or absence of anti‐HBs and anti‐HBc. These patients had been included in a controlled study on the safety, tolerability, and efficacy of three types of interferon‐α given at a dose of 3 MU three times weekly for 52 weeks. One hundred and two patients had HCV genotype 1, 42 a non‐1 HCV genotype and 3 multiple HCV genotypes; 46 were anti‐HBs and anti‐HBc negative (group A), 50 anti‐HBs and anti‐HBc positive (group B), and 51 anti‐HBs negative and anti‐HBc positive (“isolated” anti‐HBc, group C). Serum HBV‐DNA was detected by polymerase chain reaction in 15 of the 51 (29.4%) patients in group C and in none of those in groups A or B. The Sustained Response rate was higher in patients with a non‐1 HCV genotype than those with HCV genotype 1 (31% vs. 17.7%, P > 0.1). Fewer patients in group C showed a sustained response than in group A or group B (7.8% vs. 30.4%, P = 0.009 and 7.8% vs 28%, P = 0.017, respectively). Moreover, the sustained response rate was high in patients with a non‐1 genotype, both in group A (42.8%) and in group B (42.8%), intermediate in patients with HCV genotype 1 (23.3% in group A and 22.2% in group B) and low in group C, irrespective of HCV genotype (8.3% for genotype 1 and 7.1% for other genotypes). The data indicate that patients with HCV chronic hepatitis and isolated anti‐HBc show a poor response to IFN‐α, irrespective of the HCV genotype. J. Med. Virol. 65:681–687, 2001. © 2001 Wiley‐Liss, Inc.
Parenteral and oral immunization with a plasmid DNA expressing the human papillomavirus 16‐L1 gene induces systemic and mucosal antibodies and cytotoxic T lymphocyte responses
Authors: Rocha‐Zavaleta Leticia , Alejandre Jorge E. , Garcia‐Carranca Alejandro
Published: August 2002

The association of human papillomavirus (HPV) infection and cervical cancer has been demonstrated. The development of a prophylactic vaccine to protect against primary HPV infection may therefore be an efficient means to reduce the incidence of this cancer worldwide. To assess the capacity of a plasmid DNA that expresses the L1 gene of HPV type 16 to induce a protective immune response, mice were immunized by parenteral and oral routes. Animals that received the DNA vaccine intramuscularly, subcutaneously and orally, developed systemic anti‐L1 IgG antibodies. Antibodies developed in mice vaccinated subcutaneously were detectable twelve months post‐immunization. Specific IgA antibodies were also found in vaginal washes from immunized mice. Both systemic and local antibodies proved effective in a surrogate neutralization assay. Splenic T cells extracted from experimental mice showed cytotoxic T lymphocytes (CTL) activity mediated by CD8 + cells. Mice were challenged with a syngeneic melanoma cell line, engineered to express the HPV16‐L1 protein, tumours in vaccinated animals showed slower growth rate, correlated directly with a longer survival of mice. The results suggest that the L1‐based DNA vaccine may be useful for the prevention of primary infections by HPV16. J. Med. Virol. 66:86–95, 2002. © 2002 Wiley‐Liss, Inc.
Characteristics of Epstein‐Barr virus isolated from the malignant lymphomas in Korea
Authors: Kim Insun , Park Eui‐Ryun , Park Seol‐Hee , Lin Zhenhua , Kim Young‐Sik
Published: August 2002

Epstein‐Barr virus (EBV) is a common herpes virus linked to a variety of human neoplasms. In this study, the EBV detection was identified with the paraffin‐embedded tissues from 62 non‐Hodgkin's lymphomas, 20 Hodgkin's lymphomas, and 48 non‐neoplastic tonsils, using PCR for EBNA‐1 and EBER‐1 mRNA in situ hybridization for EBER‐1 mRNA. The isolates were analyzed for type 1/2, variants C/D and F/f, and LMP‐1 30 bp deletion. EBV was isolated in 31 of 48 (66%) non‐neoplastic tonsils, 24 of 42 (57%) B cell lymphomas, in 15 of 20 (75%) T cell lymphomas, and 17 of 20 (85%) Hodgkin's lymphomas. These viruses were classified as type 1 for 81% of non‐neoplastic tonsils, 95% of B cell lymphomas, 93% of T cell lymphomas, and 73% of Hodgkin's diseases. Both type 1 and 2 viruses were isolated in one non‐neoplastic tonsil and 3 Hodgkin's diseases. Type C virus was predominant in non‐neoplastic tonsils (77%) and B cell lymphomas (75%), while type D virus was common in T cell lymphomas (71%) and Hodgkin's diseases (73%) (P < 0.05). Majority of the viruses detected in non‐neoplastic tonsils (93%) and malignant lymphomas (91%) were “F” prototype. LMP‐1 30 bp deletion was found in high frequency in both non‐neoplastic tonsils (92%) and malignant lymphomas (86%). In conclusion, most of EBV found in Korea was type 1, and “DF” genotype was more frequent in T cell lymphomas and Hodgkin's diseases than in non‐neoplastic tonsils and B cell lymphomas. LMP‐1 30 bp deletion did not seem to be associated with malignant lymphomas. J. Med. Virol. 67:59–66, 2002. © 2002 Wiley‐Liss, Inc.
Fibronectin and laminin elicit differential behaviors from SH‐SY5Y growth cones contacting inhibitory chondroitin sulfate proteoglycans
Authors: Hynds DiAnna L. , Snow Diane M.
Published: August 2002

Neuronal growth cones integrate signals from outgrowth‐promoting molecules, e.g., laminin (LN) or fibronectin (FN), and outgrowth‐inhibiting molecules, e.g., chondroitin sulfate proteoglycans (CSPGs), to navigate through extracellular matrix (ECM). Sensory neurons on LN typically turn to avoid areas rich in inhibitory CSPGs, whereas neuron‐like cells of human origin (SH‐SY5Y) preferentially stop/stall. These different behaviors may reflect differences in neuron type, response to outgrowth‐promoters, or the mechanisms involved in outgrowth vs. inhibition. We used image analysis to determine the effects of different outgrowth promoters on the response of SH‐SY5Y cells to inhibitory CSPGs. LN increased neurite initiation and elongation compared to cells plated either on endogenous matrix or FN. On a patterned substratum consisting of alternating stripes of FN and CSPGs, 59.6 ± 9.3% of SH‐SY5Y growth cones turned upon CSPG contact, whereas only 31.9 ± 8.2% of growth cones turned at a LN/CSPG border. Growth cones on LN spread more upon contact with CSPG than growth cones on FN, whereas growth cones on LN or FN not contacting CSPGs were morphologically similar. Because it is known that integrins are involved in outgrowth on promoters, we analyzed integrin expression in response to inhibitory CSPGs in a choice assay. CSPGs did not induce increases or redistribution of several integrin subunits in SH‐SY5Y cells. Furthermore, an anti‐β1 integrin function‐blocking antibody did not alter growth cone behavior at a CSPG border. These results indicate that significant mechanistic differences may exist between outgrowth on homogenous outgrowth promoters and growth cone turning at inhibitory molecules. J. Neurosci. Res. 66:630–642, 2001. © 2001 Wiley‐Liss, Inc.
N‐methyl‐D‐aspartate receptors: Transient loss of NR1/NR2A/NR2B subunits after traumatic brain injury in a rodent model
Authors: Kumar Arvind , Zou Linglong , Yuan Xiaoqing , Long Yan , Yang Keyi
Published: August 2002

Hippocampal N‐methyl‐D‐aspartate (NMDA) receptor subunits, by virtue of their involvement in excitotoxic injury as well as memory association, may play an important role in the pathophysiologic mechanisms of traumatic brain injury (TBI). In this study, temporal changes in NMDA receptor subunit (NR1, NR2A, and NR2B) levels in rat hippocampus after TBI were investigated by Western blot and mRNA expression levels by RT‐PCR methods. Sprague‐Dawley rats (250–350 g) were employed, and a controlled cortical impact injury device was used to produce the TBI in rodents. At different postinjury time points (2, 6, 12, 24, and 48 hr), the rat hippocampi were dissected out for protein and RNA preparation. Western blot analysis revealed significant decreases of NR1, NR2A, and NR2B subunit proteins at 6 and 12 hr postinjury in rat hippocampus. Complete recovery of NR1, NR2A, and NR2B subunit protein to the levels of sham controls was observed at 24 hr postinjury. However, RT‐PCR analysis did not show any significant change in the mRNA levels at 2, 6, and 12 hr postinjury in comparison with sham controls, suggesting nontranscriptional change in the levels of these subunits. Thus, TBI can produce transient degradation of NMDA receptor subunits in the hippocampus, which might contribute to temporary memory impairment after injury. © 2002 Wiley‐Liss, Inc.
Ca2+‐independent caspase‐3 but not Ca2+‐dependent caspase‐2 activation induced by oxidative stress leads to SH‐SY5Y human neuroblastoma cell apoptosis
Authors: Amoroso Salvatore , D'Alessio Angela , Sirabella Rossana , Di Renzo Gianfranco , Annunziato Lucio
Published: August 2002

Continuous and long‐lasting exposure to tert‐butylhydroperoxide (t‐BOOH) increased the number of apoptotic SH‐SY5Y human neuroblastoma cells both in the presence and in the absence of the intracellular Ca2+ ion chelator 1,2‐bis(o‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid (BAPTA). In addition, t‐BOOH exposure induced activation of CPP32, as demonstrated by poly‐(ADP‐ribose) polymerase (PARP) cleavage, and of ICH‐1L caspases. Exposure to t‐BOOH also induced a time‐dependent release of cytochrome c. Interestingly, in the presence of BAPTA, CPP32 activation still occurred, whereas ICH‐1L activation was blocked. Ac‐DEVD‐CHO, an inhibitor of CPP32 activity, prevented the appearance of apoptotic cells, whereas the inhibitor of ICH‐1L activity Z‐VDVAD‐FMK did not. Collectively, these findings demonstrate that in SH‐SY5Y neuroblastoma cells exposure to continuous and long‐lasting oxidative stress induced activation of caspase‐3 that was independent of intracellular Ca2+ ion concentration ([Ca2+]i) elevation but led to cell apoptosis. In contrast, caspase‐2 activation was dependent on [Ca2+]i increase but did not result in apoptosis. © 2002 Wiley‐Liss, Inc.
Cellular mechanisms of connexin32 mutations associated with CNS manifestations
Authors: Kleopa Kleopas A. , Yum Sabrina W. , Scherer Steven S.
Published: August 2002

Both oligodendrocytes and myelinating Schwann cells express the gap junction protein connexin32 (Cx32). Mutations in the gene encoding Cx32 (GJB1) cause the X‐linked form of Charcot‐Marie‐Tooth disease (CMTX). Although most CMTX patients do not have clinical central nervous system (CNS) manifestations, subclinical evidence of CNS dysfunction is common. We investigated the cellular effects of a subgroup of GJB1/Cx32 mutations that have been reported to cause clinical CNS dysfunction. We hypothesized that these mutants have dominant‐negative effects on other connexins expressed by oligodendrocytes, specifically Cx45. We expressed these and other Cx32 mutants in communication‐incompetent as well as Cx45‐expressing HeLa cells, and analyzed the transfected cells by immunocytochemistry and immunoblotting. In communication‐incompetent cells, the mutants associated with CNS phenotypes failed to reach the cell membrane and were instead retained in the endoplasmic reticulum (A39V, T55I) or Golgi apparatus (M93V, R164Q, R183H), although rare gap junction plaques were found in cells expressing M93V or R183H. In HeLa cells stably expressing Cx45, these Cx32 mutants showed a similar expression pattern, and did not alter the pattern of Cx45 expression. These results indicate that Cx32 mutants that are associated with a CNS phenotype do not interact with Cx45, but may instead have other toxic effects in oligodendrocytes. © 2002 Wiley‐Liss, Inc.
Substrate exchange properties of the high‐affinity glutamate transporter EAAT2
Authors: Dunlop John
Published: August 2002

A stable cell line expressing the predominant brain glutamate transporter EAAT2 was used for the characterization of substrate exchange as a biochemical index for discriminating between substrate and non‐substrate inhibitors of the cloned EAAT2 transporter. Addition of 1 mM unlabeled D‐aspartate to cells equilibrated with [3H]D‐aspartate produced a time‐dependent depletion of the [3H] label retained by the cells. L‐Aspartate, L‐glutamate and L‐cysteate produced an equivalent degree of [3H] exchange to that observed with D‐aspartate, although the non‐substrate EAAT2 inhibitor dihydrokainate and D‐glutamate, which does not interact with the substrate binding site, failed to stimulate [3H]D‐aspartate exchange. Estimation of EC50 values for the stimulation of [3H] exchange by D‐aspartate, L‐glutamate and L‐trans‐2,4‐pyrollidine carboxylate (trans‐PDC) produced values that were in excellent agreement with the corresponding IC50 values for the same compounds to inhibit EAAT2 uptake. Moreover, trans‐PDC was found to produce a lower maximal exchange than that observed with D‐aspartate, consistent with the known partial EAAT2 substrate activity of trans‐PDC. The estimate of drug induced [3H] efflux with the cloned EAAT2 transporter represents a convenient biochemical assay for the discrimination of substrate and non‐substrate inhibitors of the EAAT2 subtype. J. Neurosci. Res. 66:482–486, 2001. © 2001 Wiley‐Liss, Inc.
A new porphycene-derived ring structure: octaethylbenzochloracene
Authors: MASUNO MAKO N. , ROBINSON BYRON C. , PHADKE AVINASH S.
Published: August 2002

The synthesis of a new ring structure, octaethylbenzochloracene (6), derived from octaethylporphycene is reported. A viable route to the benzochloracene is shown and parallels the transformation of porphyrin to benzochlorin. Octaethylbenzochloracene's spectral data shows a unique UV–vis spectrum and an interesting NMR spectrum. Unfortunately, an attempt to synthesize the analogous purpurin derivative, purpuracene (8), failed.
Vibrational bands of luminescent zinc(II)‐octaethylporphyrin using a polarization‐sensitive ‘microscopic’ multiplex CARS technique
Authors: Otto C. , Voroshilov A. , Kruglik S. G. , Greve J.
Published: August 2002

Polarization‐sensitive, multiplex coherent anti‐Stokes Raman scattering (ps‐MCARS) has been used to detect the vibrational bands of the highly luminescent zinc(II)‐octaethylporphyrin (Zn‐OEP). We show here that ps‐MCARS can be used to measure the vibrational bands under resonant conditions. Polarization‐sensitive CARS further helps to resolve composite and overlapping Raman bands on the basis of variations in vibrational symmetry. This paper also exemplifies the advantages of multiplex CARS (MCARS) spectroscopy carried out under tight focusing conditions as proposed earlier. We demonstrate that a ‘microscopic’ CARS focusing and collection system in combination with the multiplex technique allows a reduction in the amount of sample and a shortening of the measurement time. We analyse the relationship between the coherent vibrational phases and the symmetry of the different vibrational band of Zn‐OEP skeletal modes. The values of the coherent vibrational phases are similar for vibrational bands with the same symmetry. Copyright © 2001 John Wiley & Sons, Ltd.
Structure and Raman spectra of transient species in the catalytic disproportionation of hydrogen peroxide by molybdate ions
Authors: Arab M. , Bougeard D. , Aubry J. M. , Marko J. , Paul J. F. , Payen E.
Published: August 2002

The Raman spectra of the transient peroxo species [MoO4]2−, [MoO3(O2)]2−, [MoO2(O2)2]2−, [MoO(O2)3]2− and [Mo(O2)4]2− appearing during the catalytic disproportionation of hydrogen peroxide, were recorded and characterized in solutions corresponding to concentrations varying from 0 to 8.5 M H2O2. These spectra were assigned with the help of quantum chemical normal mode analyses using configuration interaction (CISD) and the B3LYP approximation. It turns out that by increasing the number of peroxo groups around the molybdenum atom the stability of the molecule and its oxidizing power are increased. Copyright © 2002 John Wiley & Sons, Ltd.
Electrophoretic patterns of microwaved and γ‐irradiated beef liver proteins
Authors: Farag R S , Hegazy R A , El‐Khawas Kh H , Farag M M
Published: August 2002

The effects of γ‐irradiation treatments (2.5, 5 and 10 kGy) and microwaves generated from an oven at low and defrost power settings for 0.5, 1 and 2 min on the total proteins and protein patterns of beef liver immediately after treatment and during frozen storage (−18 °C) for different periods were studied. Chemical analyses indicated that the protein content of beef liver was reduced after exposure to γ‐radiation or microwaves and also during frozen storage. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) was used to illustrate the changes in protein bands of different molecular weights and their percentages before and after exposure to gamma and microwave radiation. The main effect of γ‐radiation on the protein patterns of beef liver was the disappearance of some high‐molecular‐weight protein bands and the development of other bands characterised by moderate and low molecular weights. This finding indicates the degradation of beef liver proteins by γ‐irradiation. In contrast, microwave treatment caused an increase in the levels of high‐molecular‐weight protein bands with a concomitant decrease in low‐molecular‐weight protein bands. This phenomenon demonstrates the polymerisation of low‐molecular‐weight proteins under the influence of microwaves.

© 2001 Society of Chemical Industry