bluuebunny/crossref_metadata_2025 huggingface dataset:
Parallel extraction columns and parallel analytical columns coupled with liquid chromatography/tandem mass spectrometry for on‐line simultaneous quantification of a drug candidate and its six metabolites in dog plasma
Authors: Xia Yuan‐Qing , Hop Cornelis E.C.A. , Liu David Q. , Vincent Stella H. , Chiu Shuet‐Hing L.
Published: August 2002

A method with parallel extraction columns and parallel analytical columns (PEC‐PAC) for on‐line high‐flow liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for simultaneous quantification of a drug candidate and its six metabolites in dog plasma. Two on‐line extraction columns were used in parallel for sample extraction and two analytical columns were used in parallel for separation and analysis. The plasma samples, after addition of an internal standard solution, were directly injected onto the PEC‐PAC system for purification and analysis. This method allowed the use of one of the extraction columns for analyte purification while the other was being equilibrated. Similarly, one of the analytical columns was employed to separate the analytes while the other was undergoing equilibration. Therefore, the time needed for re‐conditioning both extraction and analytical columns was not added to the total analysis time, which resulted in a shorter run time and higher throughput. Moreover, the on‐line column extraction LC/MS/MS method made it possible to extract and analyze all seven analytes simultaneously with good precision and accuracy despite their chemical class diversity that included primary, secondary and tertiary amines, an alcohol, an aldehyde and a carboxylic acid. The method was validated with the standard curve ranging from 5.00 to 5000 ng/mL. The intra‐ and inter‐day precision was no more than 8% CV and the assay accuracy was between 95 and 107%. Copyright © 2001 John Wiley & Sons, Ltd.
Different quantitation approaches for xenobiotics in human urine samples by liquid chromatography/electrospray tandem mass spectrometry
Authors: Sancho Juan V. , Pozo Oscar J. , López Francisco J. , Hernández Félix
Published: August 2002

The potential of liquid chromatography combined with tandem mass spectrometry (LC/MS/MS) for the determination of pesticide metabolites in human urine at the sub‐ppb level is explored. Metabolites from two organophosphorous pesticides, 4‐nitrophenol (from parathion and parathion‐methyl) and 3‐methyl‐4‐nitrophenol (from fenitrothion), are taken as model analytes to conduct this study.

After direct injection of the urine sample (10 µL), different approaches were evaluated in order to achieve correct quantitation of analytes using an electrospray ionisation (ESI) interface. Thus, the feasibility of using external calibration was checked versus the use of different isotope‐labeled internal standards. The advantages of applying coupled‐column liquid chromatography (LC/LC) as an efficient clean‐up without any type of sample manipulation are also discussed.

The combination of LC/LC with ESI‐MS/MS allows the direct analysis of free metabolites in urine, as the automated clean‐up performed by the coupled‐column technique is sufficient for the removal of interferences that suppress the ionisation of analytes in the ESI source. Using this procedure with external calibration, good precision and recoveries, and detection limits below 1 ng/mL are reached with analysis run times of around 8 min. The hyphenated technique LC/LC/ESI‐MS/MS is proved to be a powerful analytical tool, allowing the rapid, sensitive and selective determination of 4‐nitrophenol and 3‐methyl‐4‐nitrophenol in human urine without any sample treatment. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of species‐specific components in the venom of Parabuthus scorpions from southern Africa using matrix‐assisted laser desorption time‐of‐flight mass spectrometry
Authors: Dyason Karin , Brandt Wolf , Prendini Lorenzo , Verdonck Fons , Tytgat Jan , Plessis Johan du , Müller Gerbus , Walt Jurg van der
Published: August 2002

The aim of the present study was to analyze mass spectra of scorpions belonging to the genus Parabuthus (Pocock 1890) by means of matrix‐assisted laser desorption time‐of‐flight mass spectrometry (MALDI‐TOFMS) and to construct a species‐specific venom code for species identification. The venom compositions of sixteen Parabuthus species, occurring in southern Africa, were characterized using representative peaks in the molecular mass range of 6400–8400 Da. This mass range is characteristic for the typical long‐chain neurotoxins influencing sodium channels. Only a few of these peptides have been sequenced up to now. The impetus for development of these species‐specific profiles was the observation of unique, highly reproducible mass spectral peaks within a specific species. An identification label for all the different species could be found using a minimum number of peaks. MALDI‐TOFMS is therefore proposed as a complementary method to morphological and behavioural characteristics for species and ultimately subspecies discrimination. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of paramethoxyamphetamine and other amphetamine‐related designer drugs by liquid chromatography/sonic spray ionization mass spectrometry
Authors: Mortier Kjell A. , Dams Riet , Lambert Willy E. , Letter Els A. De , Calenbergh Serge Van , Leenheer André P. De
Published: August 2002

Paramethoxyamphetamine (PMA) is an amphetamine‐like designer drug that has emerged recently on the European illicit drug market. This drug has a wicked reputation, as a number of lethal intoxications have occurred. A method using high‐performance liquid chromatography coupled to ion trap based mass spectrometry (LC/MS) is described for the determination of this compound together with 3,4‐methylenedioxymethamphetamine (XTC or MDMA), amphetamine and 3,4‐methylenedioxyamphetamine (MDA) in human matrices. A liquid/liquid extraction (LLE) was applied to whole blood, urine and postmortem tissues. Reversed‐phase liquid chromatography was performed on a narrow‐bore phenyl‐type column at a flow rate of 0.3 mL/min. A switch box allowed disposal of early‐eluting irrelevant material to waste, protecting the mass spectrometer from contamination. The column effluent was directed into an ion trap mass spectrometer by a sonic spray ionization (SSI) interface. The method was validated for all three matrices, proving the applicability of SSI even when dealing with complex biological matrices. The within‐and between‐day precisions were less than 17.5% and accuracy was below 16.2%. Weighted (1/x) quadratic calibration curves were generated ranging from 10 to 1000 ng/mL (blood and urine) or 20 to 2000 ng/g (tissue) and correlation coefficients (r2) always exceeded 0.995. In addition, the mass spectrum of PMA is given together with a proposed fragmentation pattern for the obtained LC/MS spectrum. This information can be useful for future identification of PMA with LC/MS in biological matrices as well as in confiscated powders or tablets. Copyright © 2002 John Wiley & Sons, Ltd.
Mass spectral studies on aryl‐substituted N‐carbamoyl/N‐thiocarbamoyl narcotine and related compounds
Authors: Aggarwal Shefali , Ghosh Narendra N. , Aneja Ritu , Joshi Harish , Chandra Ramesh
Published: August 2002

Positive ion mass spectral fragmentation of new N‐carbamoyl/N‐thiocarbamoyl derivatives of narcotine and compounds closely related to it are reported and discussed. The techniques used include electron impact (EI), fast‐atom bombardment (FAB), matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) and electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Prominent peaks in the mass spectra of these compounds appear to involve C‐C bond cleavage β to the amine nitrogen with loss of the 4,5‐dimethoxy(1H)isobenzofuranone moiety from their molecular ions, along with another prominent peak at m/z 382. No molecular ion peaks of these compounds were recorded in EI, whereas intense [M + H]+ ion peaks were observed in FAB and ESI spectra. MALDI also yielded [M + H]+ ion peaks in good agreement with FAB and ESI studies. Copyright © 2002 John Wiley & Sons, Ltd.
Solid‐phase derivatization of tryptic peptides for rapid protein identification by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Keough T. , Lacey M. P. , Youngquist R. S.
Published: August 2002

Solid‐phase sulfonation of tryptic peptides adsorbed to C18 µZipTips™ has been carried out to facilitate de novo sequencing with mass spectrometry. Peptides are reacted with the sulfonation reagent while they are still adsorbed to the solid phase. Excess reagent passes through the ZipTip™ to waste. Washing the products before subsequent elution from the mini‐column also affords sample cleanup prior to analysis. Near quantitative N‐terminal sulfonation can be achieved reliably at room temperature in only a few seconds. The method has been applied successfully to model peptides and to solution or in‐gel digests of proteins. Current sequencing limits are about 100 fmol of protein. Multiplexed sample sulfonation reactions have been carried out with a manual 8‐position micropipettor or using centrifugal force to reliably pass reagents and wash solutions over sample‐loaded ZipTips™. With multiplexing, overall preparation times have been reduced to about 1 min per sample. The solid‐phase format facilitates efficient use of precious digest samples by enabling them to be recovered from the matrix‐assisted laser desorption/ionization (MALDI) sample stage after mass fingerprinting, derivatized and re‐analyzed by MALDI postsource decay mass spectrometry. Copyright © 2002 John Wiley & Sons, Ltd.
MS3 using the collision cell of a tandem mass spectrometer system
Authors: Cousins Lisa M. , Thomson Bruce A.
Published: August 2002

We report the feasibility of multistage fragmentation in combination with a fast background subtraction method, yielding the equivalent of MS3. The first quadrupole selects an ion of interest, and the ion is axially accelerated into Q2 to generate fragment ions. Subsequent stages of mass selection and fragmentation are obtained by quadrupolar resonant excitation within the Q2 collision cell. The fragments are analyzed downstream by either a resolving quadrupole or a time‐of‐flight (TOF) mass spectrometer, and multistage spectra are obtained by subtraction (MSn − MSn−1) for n = 3 or 4. We discuss the characterization of this method, including product ion arrival times, fragmentation efficiencies, and ion selectivity. We report accurate TOF mass spectra of background‐subtracted MS3 for protonated molecules reserpine (m/z 609), bosentan (m/z 1552), and taxol (m/z 854). Copyright © 2002 John Wiley & Sons, Ltd.
Influence of the eluent composition on the ionization efficiency for morphine of pneumatically assisted electrospray, atmospheric‐pressure chemical ionization and sonic spray
Authors: Dams Riet , Benijts Tom , Günther Wolfgang , Lambert Willy , Leenheer André De
Published: August 2002

A comparative study of three atmospheric‐pressure ionization (API) sources for liquid chromatography/mass spectrometry (LC/MS), namely pneumatically assisted electrospray or ionspray (IS), atmospheric‐pressure chemical ionization (APCI), and sonic spray (SS), with respect to the influence of the eluent composition on the ionization of morphine, is presented. The effect of organic modifiers, volatile acids, and buffer systems (with and without pH adjustment) in the LC mobile phase on the ionization efficiency of each interface is described. We conclude that for all three ion sources, the composition of the liquid phase had a serious impact on the ionization of the target compound. For IS and SS, very similar behavior towards the LC eluent was observed. In both cases, an increase in organic modifier resulted in an increase in ionization, while an increasing amount of volatile acid or buffer caused signal suppression. APCI, on the other hand, proved to respond completely differently towards the changes in the eluent. Again, an increased ionization was observed with an increase in organic modifier content but this time also in the presence of mobile phase additives like acids or buffers. Finally, we concluded that APCI proved to be the preferred ion source for the test compound because of its robust character and its direct applicability in traditional LC analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Passive Treatment Alternatives for Remediating Abandoned‐Mine Drainage
Authors: Berghorn George H. , Hunzeker George R.
Published: August 2002

Abandoned‐mine drainage (AMD) is drainage flowing from or caused by surface mining, deep
mining, or coal refuse piles that is typically highly acidic with elevated levels of dissolved metals. AMD
results from the interactions of certain sulfide minerals with oxygen, water, and bacteria. Passive treatment
systems have been used to remediate AMD at numerous sites throughout the United States. The theory behind
passive treatment is to allow naturally occurring chemical, biological, and physical reactions that aid in AMD
treatment to occur in the controlled environment of the system, not in the receiving water body. The advantages
of passive treatment over active treatment include lower operation and maintenance costs, virtually no use of
chemicals, and minimal energy consumption. The disadvantages are that smaller volumes of water are treated than
with active systems, and discharges with high concentrations of dissolved metals and extremes of pH may have to
be treated several times within one system to treat the discharge. AMD passive treatment systems include aerobic
treatment systems and anaerobic treatment systems. It is estimated that it will take 50 years and between
$5 billion and $15 billion to remediate all AMD problems in Pennsylvania. © 2001 John Wiley
& Sons, Inc.
The flood of the century on the River Oder: effects on the 0+ fish community and implications for floodplain restoration
Authors: Bischoff A. , Wolter C.
Published: August 2002

In summer 1997, the flood of the century occurred on the River Oder in the Czech Republic, Poland and Germany. Effects of the summer flood on the 0+ fish community were evaluated at the Lower Oder in the Polish–German National Park. Fish were collected from different mesohabitats before the flood, at rising water levels and after the flood using Point Abundance Sampling by electrofishing. Flooding caused changes in local 0+ fish assemblages and partly affected the physical habitat structure. Two sandbars were formed by breaches in the dike system, replacing the former uniform river embankments. Under post‐flood conditions, diversity was increased in nearly all mesohabitats. ‘Wash‐out’ of 0+ fish was highest in poorly structured mesohabitats. Effects of the summer flood on eurytopic species were the most pronounced. We suggest that the progeny of rheophilic species were affected to a lesser extent by flooding because of their adaptation to variable flow conditions. Furthermore, rheophilic 0+ fish were able to colonize the newly created mesohabitats and, thus, benefited from the increased habitat heterogeneity after the flood. In this context, implications for floodplain restoration are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Exploratory research: citizen participation, local government and sustainable development in Australia
Authors: Cuthill Michael
Published: August 2002

Exploratory research reported in this paper was undertaken in Adelaide, Australia during 1998/99. The purpose of the research is to explore local development practice as evidenced through the experiences and actions of local citizens, community based groups and local government (Neuman, 1994). Results from this first stage research suggest that sustainability initiatives in Australia might best be implemented through a collaborative approach at the local community level involving local citizens working in partnership with local government. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Rejoinder to Homer and Oliva
Authors: Coyle Geoff
Published: August 2002

This rejoinder clarifies that there is significant agreement between my position and that of Homer and Oliva as elaborated in their response. Where we differ is largely to the extent that quantification offers worthwhile benefit over and above analysis from qualitative analysis (diagrams and discourse) alone. Quantification may indeed offer potential value in many cases, though even here it may not actually represent “value for money”. However, even more concerning is that in other cases the risks associated with attempting to quantify multiple and poorly understood soft relationships are likely to outweigh whatever potential benefit there might be. To support these propositions I add further citations to published work that recount effective qualitative‐only based studies, and I offer a further real‐world example where any attempts to quantify “multiple softness” could have lead to confusion rather than enlightenment. My proposition remains that this is an issue that deserves real research to test the positions of Homer and Oliva, myself, and no doubt others, which are at this stage largely based on personal experiences and anecdotal evidence. Copyright © 2001 John Wiley & Sons, Ltd.
Sample size requirements for estimating intraclass correlations with desired precision
Authors: Bonett Douglas G.
Published: August 2002

A method is developed to calculate the approximate number of subjects required to obtain an exact confidence interval of desired width for certain types of intraclass correlations in one‐way and two‐way ANOVA models. The sample size approximation is shown to be very accurate. Copyright © 2002 John Wiley & Sons, Ltd.
Wealth and the effects of founder management among IPO‐stage new ventures
Authors: Certo S. Trevis , Covin Jeffrey G. , Daily Catherine M. , Dalton Dan R.
Published: August 2002

IPO underpricing is inherently related to both wealth retention and wealth creation. This paper reviews the relationship between IPO underpricing and wealth, then presents the results of an empirical study of the impact of CEO founder status (i.e., is the CEO also the founder?) on IPO underpricing. Results based on data collected from 368 IPO‐stage new ventures suggest that founder management has a positive impact on IPO underpricing, and that the founder management–underpricing relationship is moderated by (a) the IPO market share of the investment banker employed and (b) the proportion of insiders on the IPO firm's board of directors. Copyright © 2001 John Wiley & Sons, Ltd.
Reducing the overhead of dynamic compilation
Authors: Krintz Chandra J. , Grove David , Sarkar Vivek , Calder Brad
Published: August 2002

The execution model for mobile, dynamically‐linked, object‐oriented programs has evolved from fast interpretation to a mix of interpreted and dynamically compiled execution. The primary motivation for dynamic compilation is that compiled code executes significantly faster than interpreted code. However, dynamic compilation, which is performed while the application is running, introduces execution delay. In this paper we present two dynamic compilation techniques that enable high performance execution while reducing the effect of this compilation overhead. These techniques can be classified as (1) decreasing the amount of compilation performed, and (2) overlapping compilation with execution.

We first present and evaluatelazy compilation, an approach used in most dynamic compilation systems in which individual methods are compiled on‐demand upon their first invocation. This is in contrast toeager compilation, in which all methods in a class are compiled when a new class is loaded. In this work, we describe our experience with eager compilation, as well as the implementation and transition to lazy compilation. We empirically detail the effectiveness of this decision. Our experimental results using the SpecJVM Java benchmarks and the Jalapeño JVM show that, compared to eager compilation, lazy compilation results in 57% fewer methods being compiled and reductions in total time of 14 to 26%. Total time in this context is compilation plus execution time.

Next, we present profile‐driven, background compilation, a technique that augments lazy compilation by using idle cycles in multiprocessor systems to overlap compilation with application execution. With this approach, compilation occurs on a thread separate from that of application threads so as to reduce intermittent, and possibly substantial, delay in execution. Profile information is used to prioritize methods as candidates for background compilation. Methods are compiled according to this priority scheme so that performance‐critical methods are invoked using optimized code as soon as possible. Our results indicate that background compilation can achieve the performance of off‐line compiled applications and masks almost all compilation overhead. We show significant reductions in total time of 14 to 71% over lazy compilation. Copyright © 2001 John Wiley & Sons, Ltd.
PET imaging of brain acetylcholinesterase using [11C]CP‐126,998, a brain selective enzyme inhibitor
Authors: Bencherif B. , Endres C.J. , Musachio J.L. , Villalobos A. , Hilton J. , Scheffel U. , Dannals R.F. , Williams S. , Frost J.J.
Published: August 2002

PET and [11C]CP‐126,998, an N‐benzylpiperidinebenzisoxazole, were used to image brain acetylcholinesterase (AChE) distribution in healthy controls before and after administration of 5 mg donepezil p.o., a reversible AChE inhibitor. Logan plots were used to compute distribution volumes (VT). The VT of [11C]CP‐126,998 was highest in the basal ganglia and cerebellum and lowest in the cerebral cortex, thalamus, amygdala, and hippocampus. The regional VT values correlated well with AChE concentration measured in vitro. Donepezil, given 4 h before PET scanning, induced a substantial inhibition of [11C]CP‐126,998 binding (43–62%) in all brain regions when compared to the baseline PET study. The results of this study indicate that PET imaging of [11C]CP‐126,998 may be useful in quantifying the distribution of regional brain AChE. This new PET radiotracer may potentially be employed in the diagnosis and treatment of patients with disorders of cholinergic neurotransmission, such as Alzheimer's disease. Synapse 45:1–9, 2002. © 2002 Wiley‐Liss, Inc.
“Nonhedonic” food motivation in humans involves dopamine in the dorsal striatum and methylphenidate amplifies this effect
Authors: Volkow Nora D. , Wang Gene‐Jack , Fowler Joanna S. , Logan Jean , Jayne Millard , Franceschi Dinko , Wong Cristopher , Gatley Samuel J. , Gifford Andrew N. , Ding Yu‐Shin , Pappas Naomi
Published: August 2002

The drive for food is one of the most powerful of human and animal behaviors. Dopamine, a neurotransmitter involved with motivation and reward, its believed to regulate food intake in laboratory animals by modulating its rewarding effects through the nucleus accumbens (NA). Here we assess the involvement of dopamine in “nonhedonic” food motivation in humans. Changes in extracellular dopamine in striatum in response to nonhedonic food stimulation (display of food without consumption) were evaluated in 10 food‐deprived subjects (16–20 h) using positron emission tomography (PET) and [11C]raclopride (a D2 receptor radioligand that competes with endogenous dopamine for binding to the receptor). To amplify the dopamine changes we pretreated subjects with methylphenidate (20 mg p.o.), a drug that blocks dopamine transporters (mechanism for removal of extracellular dopamine). Although the food stimulation when preceded by placebo did not increase dopamine or the desire for food, the food stimulation when preceded by methylphenidate (20 mg p.o.) did. The increases in extracellular dopamine were significant in dorsal (P < 0.005) but not in ventral striatum (area that included NA) and were significantly correlated with the increases in self‐reports of hunger and desire for food (P < 0.01). These results provide the first evidence that dopamine in the dorsal striatum is involved in food motivation in humans that is distinct from its role in regulating reward through the NA. In addition it demonstrates the ability of methylphenidate to amplify weak dopamine signals. Synapse 44:175–180, 2002. © 2002 Wiley‐Liss, Inc.
Stress, hippocampal plasticity, and spatial learning
Authors: Garcia René
Published: August 2002

During the last two decades numerous studies have been conducted in an attempt to correlate the mechanisms of long‐term potentiation (LTP) of hippocampal synaptic transmission with those required for spatial memory formation in the hippocampus. Because stressful events block the induction of hippocampal LTP, it has been suggested that deficits in spatial learning following stress may be related to suppression of LTP‐like phenomena in the hippocampus. Here I review these studies and discuss them in light of the emerging view that stress may induce changes in thresholds for synaptic plasticity necessary for both LTP induction and spatial memory formation. This phenomenon, known as metaplasticity, may involve a glucocorticoid modulation of calcium homeostasis. Synapse 40:180–183, 2001. © 2001 Wiley‐Liss, Inc.
Nonlinear organic reactions to proliferate acidic and basic molecules and their applications
Authors: Ichimura Kunihiro
Published: August 2002

Acid amplifiers derived from a certain class of sulfonates suffer from autocatalytic decomposition in the presence of a strong acid to give corresponding sulfonic acids, which catalyze the decomposition of the parent sulfonates, leading to the liberation of more of the same sulfonic acids in an exponential manner. Five types of acid amplifiers displaying acid proliferation reactions are presented. A certain type of carbamate exhibits autocatalytic fragmentation to give the corresponding aliphatic amine and olefin together with carbon dioxide, whereas the generated amine is able to act as a catalyst for the fragmentation so that the carbamates are referred to as base amplifiers. Applications of acid and base amplifiers to photofunctional materials, including photoresists, are described as a consequence of the combination of the molecular amplifiers with photoacid as well as photobase generators. Practical applications of acid proliferation reactions in polymer films are discussed. © 2002 The Japan Chemical Journal Forum and John Wiley & Sons, Inc. Chem Rec 2: 46–55, 2002
Using a Balanced Scorecard to Implement Sustainability
Authors: Epstein Marc J. , Wisner Priscilla S.
Published: August 2002

Developing social and environmental balanced scorecard measures helps EH&S managers identify the key
performance factors that link their department's work to the company's strategic objectives. ©
2001 John Wiley & Sons, Inc.
Characterization of a Schizosaccharomyces pombe mutant deficient in UDP‐galactose transport activity
Authors: Tanaka Naotaka , Konomi Mami , Osumi Masako , Takegawa Kaoru
Published: August 2002

In fission yeast, Schizosaccharomyces pombe, the carbohydrate components of the cell wall consist of galactomannan, unlike in Saccharomyces cerevisiae. We previously found that the disruption of gms1+, a gene encoding the UDP‐galactose transporter required for the synthesis of galactomannan, led to the complete defect of cell surface galactosylation in Sz. pombe. The Δgms1 strain is therefore useful for the analysis of physiological properties of galactose residues in Sz. pombe. The deletion strain of gms1+ was viable; however, itshowed an aberrant cell morphology and increased sensitivities to digestion with β‐glucanase and to various drugs, such as hygromycin B, sodium orthovanadate and Calcofluor white. A reduction of galactomannan layers of the cell wall in the Δgms1 strain was observed by scanning and transmission electron microscopic analyses. The addition of osmotic stabilizer suppressed the morphologic defect of the Δgms1 cells, while other phenotypes were weakly suppressed. The Δgms1 (h90) strain was incapable of sexual conjugation during nutritional starvation. These results suggest that the cell surface galactosylation is required not only for non‐sexual flocculation but also for sexual conjugation in Sz. pombe. Copyright © 2001 John Wiley & Sons, Ltd.
The sequence of a 15 769 bp segment of Pichia anomala identifies the SEC61 and FBP1 genes and five new open reading frames
Authors: Ruíz Teresa , Sánchez Manuel , De la Rosa José M. , Rodríguez Luis , Domínguez Angel
Published: August 2002

We have determined the sequence of a 15 769 bp DNA segment of Pichia anomala. The sequence contains seven complete open reading frames (ORFs) longer than 100 amino acids and a putative tRNA gene. Two of the ORFs code for the well‐characterized genes SEC61 (which codes for the core subunit of the ER translocation complex) and FBP1 (encoding fructose‐1,6‐bisphosphatase). A gene coding for a protein similar to S. cerevisiae YDL054c was found between the two genes. These three genes show a different organization (intermingled triples) in three yeast species: Saccharomyces cerevisiae, Candida albicans and P. anomala. Two out of the four remaining ORFs show weak homology with different proteins from other species and the other two show non‐significant similarity with previously sequenced genes. The nucleotide sequence has been submitted to the EMBL database under Accession No. AJ306295. Copyright © 2001 John Wiley & Sons, Ltd.
Phylogenetic footprinting reveals multiple regulatory elements involved in control of the meiotic recombination gene, REC102
Authors: Jiao Kai , Nau John J. , Cool Marc , Gray William M. , Fassler Jan S. , Malone Robert E.
Published: August 2002

REC102 is a meiosis‐specific early exchange gene absolutely required for meiotic recombination in Saccharomyces cerevisiae. Sequence analysis of REC102 indicates that there are multiple potential regulatory elements in its promoter region, and a possible regulatory element in the coding region. This suggests that the regulation of REC102 may be complex and may include elements not yet reported in other meiotic genes. To identify potential cis‐regulatory elements, phylogenetic footprinting analysis was used. REC102 homologues were cloned from other two Saccharomyces spp. and sequence comparison among the three species defined evolutionarily conserved elements. Deletion analysis demonstrated that the early meiotic gene regulatory element URS1 was necessary but not sufficient for proper regulation of REC102. Upstream elements, including the binding sites for Gcr1p, Yap1p, Rap1p and several novel conserved sequences, are also required for the normal regulation of REC102 as well as a Rap1p binding site located in the coding region. The data in this paper support the use of phylogenetic comparisions as a method for determining important sequences in complex promoters. Copyright © 2002 John Wiley & Sons, Ltd.
The Verified Incremental Design of a Distributed Spanning Tree Algorithm: Extended Abstract
Authors: Hesselink Wim H.
Published: August 2002

The paper announces an incremental mechanically–verified design of the algorithm of Gallager, Humblet, and Spira for the distributed determination of the minimum-weight spanning tree in a graph of processes. The processes communicate by means of asynchronous messages with their neighbours in the graph. Messages over one link may pass each other. The proof of the algorithm is based on ghost variables, invariants, and a decreasing variant function. The verification is mechanized by means of the theorem prover Nqthm of Boyer and Moore. This extended abstract is an introduction to the full paper that can be obtained by ftp (http://link.springer.de/link/service/journals/00165/).
Genetic Aspects of Male Infertility
Authors: Namiki Mikio
Published: August 2002

Abstract

Genetic factors affecting male infertility are reviewed. Male infertility is classified under four general causes: spermatogenic disorder, obstruction of the seminal tract, inflammation, sexual disorders. Idiopathic spermatogenic disorder accounts for more than 50% of all of them. The cause of spermatogenic disorder is not yet identified. In recent years it has become obvious that some of the crucial genes expressed during male germ cell differentiation exist on the long arm of Y chromosome (Yq). Identification of a gene specifically involved in sperm production could provide a more rational basis for the treatment of male infertility. In this paper I review the history of azoospermia factor (AZF), which is involved in sperm production, and describe our research on a novel AZF candidate. In 1993 Ma and coworkers isolated an AZF candidate named YRRM; and in 1995 Reijo and coworkers reported another AZF candidate known as DAZ. The existence of additional genes on Yq is strongly suspected. We are now seeking a novel AZF candidate using positional cloning and an exon trapping method. The candidate should be included in the YAC yOX21 covering microdeleted portion of Yq found by analyzing DNA obtained from many infertile men. Several unknown sequences were identified by the analysis. Ongoing studies on AZF will prove useful in the diagnosis and treatment of male infertility.
Living Donor Lung Transplantation
Authors: Cohen Robbin G. , Starnes Vaughn A.
Published: August 2002

Since 1993 a total of 101 living‐donor bilateral lung transplants have been performed with acceptable results when compared with those utilizing cadaveric lung grafts. Though most recipients were patients with cystic fibrosis who were rapidly deteriorating, the indications for livedonor lung transplantation have been expanded to include some cystic fibrosis patients in a more elective setting, as well as select patients with other end‐stage pulmonary diseases. One‐year Kaplan‐Meier recipient survival is 72%. Seventy‐six percent of deaths occur within the first 2 months after transplantation. The most common cause of death is infection, which accounts for 62% of the 1‐year mortality rate. The incidence of rejection is 0.8 episodes per patient. Thirty percent of rejection episodes are unilateral, and most tend to be mild. Altogether, 203 patients have undergone donor lobectomy, with a mean age of 37 ± 12 years (range 18–56 years). Operations included left lower lobectomy (102 patents), right lower lobectomy (97 patients), and right middle and lower lobectomy (4 patients). There has been no donor mortality. Postoperative Rand 36 Question Quality of Life scores, rating physical function, social functioning, and role limitation due to physical and emotional health, are well over 92 (of a possible score of 100). Eighty‐five percent of donors said that their health was no different or improved since donation.
Surgery and Prognostic Factors for Gastric Stromal Tumor
Authors: Kwon Sung Joon ,   Members of the Korean Gastric Cancer Study Group
Published: August 2002

Morphologic studies of gastric stromal tumors (GSTs) indicate that mitotic counts (MCs) and tumor size are major discriminants predictive of biologic behavior. The purpose of this study is to improve the understanding of GST behavior, including the prognostic factors and surgical treatment of GSTs. A retrospective analysis (1990–1997) of the clinical course for 116 patients with GSTs was completed, with a median follow‐up of 43 months. Tumors were categorized as malignant GSTs (n= 17) when the MC was > 5/50 high‐power fields (HPF) and the size > 5 cm or as benign GSTs (n= 99) when the MC was ≤ 5/50 HPF and the size ≤ 5 cm, MC ≤ 5/50 HPF and size > 5 cm, or MC > 5/50 HPF and size ≤ 5 cm. None of 99 benign tumors recurred or metastasized, whereas 7 of 17 malignant tumors recurred. MCs had a close correlation with tumor size. Immunohistochemical studies using CD34, smooth muscle actin, S‐100 protein, and synaptophysin have shown positive rates of 61%, 33%, 14%, and 3%, respectively. Smooth muscle actin reactivity was more common in the benign tumors (p= 0.046) and synaptophysin reactivity in the malignant tumors (p= 0.010). Univariate analysis showed that the following clinicopathologic factors were potentially related to poor survival of patients: (1) MC > 5/50 HPF (p= 0.0001); (2) severe pleomorphism (p= 0.0062); (3) necrosis (p= 0.0173); (4) marked cellularity (p= 0.0112); (5) presence of ulceration of overlying gastric mucosa (p= 0.0091); (6) tumor size > 5 cm (p= 0.0195); and (7) exogastric growth pattern (p= 0.0344). Tumors with MC > 5/50 HPF and size > 5 cm were found to be strong indicators of an unfavorable prognosis. The type of surgery and tumor site did not affect the prognosis of the patients.
Identification and Management of Intravagal Parathyroid Adenoma
Authors: Pawlik Timothy M. , Richards Melanie , Giordano Thomas J. , Burney Richard , Thompson Norman
Published: August 2002

Intravagal parathyroid adenomas are rare, with only three cases reported in the English literature. The objective of this report is to describe two additional patients with hyperfunctioning parathyroid glands found within the vagus nerve and to define the anatomy of this finding. Both patients presented with a history of persistent hyperparathyroidism despite multiple therapeutic interventions. A high cervical localization was established in both cases by selective venous sampling. In each patient successful removal of the intravagal parathyroid gland was achieved with subsequent resolution of calcium and parathyroid levels. Each adenoma was located within the vagus nerve below the level of the carotid bifurcation and was enucleated without sacrificing the vagus nerve. In our cases and those reported previously, the parathyroid glands were supernumerary, representing parathyroid tissue embryologically derived from the third branchial pouch. Exploration for hyperparathyroidism requires a complete, meticulous surgical dissection to identify all parathyroid glands and to search for possible accessory tissue in selected cases. Our experience and a review of the literature serve to emphasize that, although rare, intravagal parathyroid adenomas do occur. Examination of the vagus nerve should therefore be strongly considered when four normal glands are found, as intravagal adenomas appear to represent accessory ectopically located parathyroid tissue.
Surgical Management for Carcinoid Tumors of Small Bowel, Appendix, Colon, and Rectum
Authors: Stinner B. , Kisker O. , Zielke A. , Rothmund M.
Published: August 2002

Carcinoid tumors occur most frequently in the gastrointestinal tract. Despite their ability to produce hormones, most of the midgut and hindgut carcinoids covered in this study are clinically silent, and the diagnosis is often not made before emergency surgery or evaluation for liver metastases. Because the rate of lymph node involvement and the prognosis of carcinoid tumors depend on their site and size, surgery refers to these two factors too. Lymph node metastases are most commonly found with small bowel carcinoids (20–45%), providing the rationale for an extended resection including the adjacent lymph node drainage area. Carcinoid tumors of the appendix < 1 cm in diameter rarely metastasize, simply requiring appendectomy for treatment. Lesions > 2 cm should be treated by right hemicolectomy because of their approximately 30% risk of lymph node metastases. Resection should always be done for carcinoid tumors of the colon resection as for adenocarcinomas. Rectal carcinoids < 2 cm rarely metastasize, directing the conclusion that for these smaller lesions local excision is sufficient; for lesions >2 cm a standard cancer resection should be performed provided distant metastases are absent. In general, the younger the patient or the larger the primary tumor, the more aggressive the treatment should be.
Enhanced Expression of Manganese Superoxide Dismutase mRNA and Increased TNFα mRNA Expression by Gastric Mucosa in Gastric Cancer
Authors: Izutani Ryo , Katoh Michio , Asano Satoshi , Ohyanagi Harumasa , Hirose Kunitaka
Published: August 2002

Manganese superoxide dismutase (Mn‐SOD), a mitochondrial enzyme, is a cytokine‐regulated acute‐phase protein that protects cells from free radicals. The current investigations examined the in vivo regulation of the expression of Mn‐SOD mRNA and tumor necrosis factor α (TNFα) mRNA in gastric carcinoma tissue. The expression of these transcripts in breast carcinoma tissue also was examined because breast cancer is a much more TNF‐sensitive tumor than gastric cancer. TNFα mRNA was markedly increased in gastric carcinoma tissue (p< 0.005). There were significantly higher levels of Mn‐SOD mRNA in gastric carcinoma tissue than in noncancerous tissue (p< 0.0001). The level of Mn‐SOD mRNA in gastric carcinoma tissue was higher than that in breast carcinoma tissue (p< 0.005). Up‐regulation of Mn‐SOD mRNA in gastric carcinoma tissue most likely serves as a protective mechanism against superoxide radicals and TNF cytotoxicity.
Gut Origin Sepsis, Macrophage Function, and Oxygen Extraction Associated with Acute Pancreatitis in the Rat
Authors: Wang Xiangdong , Andersson Roland , Soltesz Vasile , Leveau Per , Ihse Ingemar
Published: August 2002

It has been suggested that the gut plays a role in the development of bacterial complications, which are important contributors to morbidity and mortality in patients with acute pancreatitis. The present study evaluated the enteric bacterial translocation, bacterial homeostasis, and reticuloendothelial system function in experimental acute pancreatitis induced by intraductal injection of 5% sodium taurodeoxycholate in the rat. The incidence of bacterial translocation from the gut to mesenteric lymph nodes (MLNs) and lungs significantly increased after 12 hours and to the systemic circulation, ascites, and pancreas at 24 hours. The number of anaerobic bacteria and lactobacilli decreased in the colon and distal ileum from 6 or 12 hours, whereas the number ofEscherichia coliincreased from 12 hours. The systemic uptake rate of radiolabeled bacteria decreased from 6 hours after induction of acute pancreatitis. The uptake of radiolabeled bacteria by Kupffer cells decreased from 6 hours, whereas the uptake by macrophages from blood, lungs, and the intestine increased. A decrease in macrophage killing capacity was noted, reflected by an increase in the number of cultured viable bacteria from isolated macrophages. The whole‐body oxygen extraction rate increased 4 to 24 hours after induction of pancreatitis, whereas the gut oxygen extraction rate decreased at 2 and 4 hours, followed by an increase at 12 to 24 hours. These data show that translocation of enteric bacteria occurs during the early stage of acute pancreatitis and that the MLN–thoracic duct–circulation may be a major route of bacterial dissemination. Compromised gut oxygen metabolism, overexaggerated intestinal macrophages, and impaired host immune function may be involved in the development of infectious complications associated with acute pancreatitis.
Anterior Approach for Difficult Major Right Hepatectomy
Authors: Lai Edward C.S. , Fan Sheung‐Tat , Lo Chung‐Mau , Chu Kent‐Man , Liu Chi‐Leung
Published: August 2002

In selected patients with huge right hepatic tumors that had infiltrated the surrounding structures, injudicious mobilization of the liver before transection, as in the conventional manner, may result in excessive bleeding, prolonged ischemia from rotation of the hepatoduodenal ligament, and spillage of cancer cells into the systemic circulation. Alternatively, the “anterior” approach, which involves initial completion of the parenchymal transection before the right hepatic lobe is mobilized, can be adopted for these patients with difficult right hepatic tumors. After hilar control of the inflow vessels, liver parenchyma was transected using an ultrasonic dissector until the anterior surface of the inferior vena cava is exposed. The right hepatic lobe is then mobilized laterally by securing all venous tributaries, including the right hepatic vein. The prospective data of 25 patients who had major right hepatectomy using the “anterior” approach were compared with data from 34 patients who had their operation performed in the conventional manner. Despite the facts that larger tumors (p< 0.004), more extrahepatic structures (p< 0.05), and the caudate lobes (p< 0.03) were resected, the amount of perioperative blood transfusion, fluid replacement, and outcome between the two groups of patients were comparable. There were three hospital deaths, among which one could be attributed to an intraoperative catastrophe during hepatectomy using the conventional approach. The “anterior” approach is a safe, effective option for selected patients undergoing complicated major right hepatectomy.
Prophylactic Surgery for Multiple Endocrine Neoplasia Type IIa after Genetic Diagnosis: Is Parathyroid Transplantation Indicated?
Authors: Decker Ruth A. , Geiger James D. , Cox Charles E. , Mackovjak Marilyn , Sarkar Minakshi , Peacock Michael L.
Published: August 2002

Identification of germline mutations in theRETproto‐oncogene predisposing to multiple endocrine neoplasia type IIa (MEN‐IIa) has allowed a DNA‐based approach to diagnosis and treatment by prophylactic thyroidectomy in children testing genetically positive. Although total thyroidectomy is the accepted operation for C cell disease, the necessity of routine total parathyroidectomy and autotransplantation as previously described in these asymptomatic children is questionable, particularly given the low occurrence of hyperparathyroidism in MEN‐IIa (10–20%). Thirty‐six children (ages 1 month to 12 years) from four MEN‐IIa kindreds at risk for disease underwent genetic testing. Mutational analysis was done using a highly sensitive PCR‐based denaturing gradient gel electrophoresis technique. Parathyroid or serum calcium concentrations were determined preoperatively. Of the 36 children at risk, 18 were found to have a MEN‐IIa mutation; 11 have undergone prophylactic thyroidectomy at ages ranging from 2 to 12 years (mean 7.5 years). In each case, there was no biochemical evidence of hypercalcemia preoperatively, and all parathyroid glands were identified and were found to be grossly normal at exploration. Glands were carefully dissected and left in situ. Postoperatively, 10 of the 11 children maintained normocalcemia, allowing discharge within 24 to 36 hours. Resected thyroid glands contained C cell hyperplasia in nine, medullary carcinoma in one, and normal histology in one. We conclude that an alternative to routine parathyroidectomy may be desirable for prophylactic treatment of MEN‐IIa. In situ parathyroid preservation can be safely achieved without compromising the completeness of the thyroid resection. This conservative approach obviates the potential morbidity associated with total parathyroidectomy and autotransplantation.
Gip‐2Codon 179 Oncogene Mutations: Absent in Adrenal Cortical Tumors
Authors: Demeure Michael J. , Doffek Kara M. , Komorowski Richard A. , Gorski Jack
Published: August 2002

The role of G protein mutations in the pathogenesis of adrenal cortex neoplasms is controversial. Two published studies disagree on the existence of a cysteine or histidine for arginine substitution at position 179 (R179C/H) of the GTP binding region of the α chain of an inhibitory G protein (Gi2α) in these tumors. Prior studies using detection by mutation‐specific oligonucleotide hybridization showed either 3 of 11 or 0 of 56 tumors harbored mutations. To resolve this discrepancy and ascertain the importance of the R179C/H Gi2α mutation in the development of adrenal cortex tumors, we screened tumors from 29 patients (24 with adenoma, 5 with carcinoma) using a more sensitive assay employing polymerase chain reaction (PCR) and examination for restriction fragment length polymorphisms (RFLP). Detection of the potential R179C/H mutation by this technique was possible because the wild‐type coding sequence includes the BSTU‐1 restriction endonuclease recognition site CGCG, whereas the mutated gene does not. Results showed complete digestion of the amplified DNA samples from all 29 patients and the negative control DNA by BSTU‐1, indicating that all tumor samples exhibited only the wild‐type sequence. Direct sequencing of PCR product from four tumor samples confirmed the presence of only the wild‐type sequence. The 0 of 29 rate of R179C/H mutations we found in Gi2α is different than the 3 of 11 positive rate (p< 0.05, Fishers’ exact) previously reported but agrees with the report showing 0 of 56 mutations. We conclude a mutation at position 179 of Gi2α is not important in the pathogenesis of most adrenal cortical tumors.