bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexible open‐cell design for internal‐source matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
Authors: Frankevich Vladimir , Zenobi Renato
Published: August 2002

A new Fourier transform ion cyclotron resonance (FTICR) cell design is described that improves the performance of internal‐source matrix‐assisted laser desorption/ionization (MALDI) applications. The design employs a capacitively coupled open FTICR cell and a ring electrode placed between the ion source and the ICR cell. The flexibility of our open‐cell design allows the use of several different trapping schemes for ion detection. Elimination of the drift time dependence in a MALDI experiment, ion accumulation, RF ion selection, and improved trapping of MALDI ions desorbed at an angle to the surface normal are some of the advantages of this design. Copyright © 2001 John Wiley & Sons, Ltd.
Mass spectrometric characterisation of proteins in rennet and in chymosin‐based milk‐clotting preparations
Authors: Lilla Sergio , Caira Simonetta , Ferranti Pasquale , Addeo Francesco
Published: August 2002

The protein composition of natural rennet and of chromatographic and crystalline chymosin preparations has been defined by on‐line reverse‐phase high performance liquid chromatography/electrospray ionisation mass spectrometry (RP‐HPLC/ESI‐MS) and by tandem mass spectrometry (MS/MS). Natural rennet was found to consist of six chymosin species, corresponding to chymosin A and B genetic variants, each of which comprised a mixture of two other forms differing at theN‐terminal end, with one being three residues longer, and the other two residues shorter, than the mature chymosin. Two main tissue proteins were also identified as lysozyme (isozyme 2 plus a novel isozyme labelled 4) and bovine serum albumin. In addition to the proteins, chymosin fragments 247–323 and 288–323 were consistently present in natural rennet. Conversely, chromatographic and crystalline chymosin preparations lacked bovine serum albumin and/or lysozyme, although they contained the same six chymosin species as natural rennet. Since these tissue‐specific contaminating proteins each possess specific functions in terms of stabilising enzyme solutions and protecting proteins from proteolytic enzymes, oxidising agents and bacterial proliferation, the rennet may be considered as a functional enzyme preparation that is effectively and naturally adapted to the purposes of cheesemaking. In practice, the highly complex protein composition inherent to natural rennet provided the possibility to differentiate the natural product from other bovine chymosin‐based milk‐clotting preparations examined in this work. Copyright © 2001 John Wiley & Sons, Ltd.
Cone voltage and collision cell collision‐induced dissociation study of triphenylethylenes of pharmaceutical interest
Authors: Makowiecki Jacek , Tolonen Ari , Uusitalo Jouko , Jalonen Jorma
Published: August 2002

Fragmentations of three triphenylethylene compounds (toremifene and its two metabolites) with different functional side‐chain groups (alcohol, acid and amine) were studied. The compounds were dissociated by collision‐induced dissociation (CID) in the interface region of an electrospray ionization source (ESI+) and in the collision cell of a triple quadrupole mass spectrometer. Fragmentation pathways for these molecules are proposed, based on accurate mass measurements of in‐source fragment ions and MS/MS experiments using product and precursor ion scanning. The side‐chain functional groups were found to strongly affect the fragmentations of the molecular ions. The fragmentation pathways of the protonated molecule and sodium ion adduct were quite similar, but the subsequent stabilities of certain common fragments were surprisingly different. Copyright © 2001 John Wiley & Sons, Ltd.
Use of nitrocellulose films for affinity‐directed mass spectrometry for the analysis of antibody/antigen interactions
Authors: Sun Shuqing , Mo Wenjun , Ji Yiping , Liu Shuying
Published: August 2002

Combination of affinity extraction procedures with mass spectrometric analyses is termed affinity‐directed mass spectrometry, a technique that has gained broad interest in immunology and is extended here with several improvements from methods used in previous studies. A monoclonal antibody was immobilized on a nitrocellulose (NC) membrane, allowing the corresponding antigen to be selectively captured from a complex solution for analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). This method was also used to rapidly determine the approximate binding region responsible for the antibody/antigen interaction. The tryptic fragments of antigen protein in buffer were applied to the antibody immobilized on NC film and allowed to interact. The NC film was then washed to remove salts and other unbound components, and subjected to analysis by MALDI‐TOFMS. Using interferon‐α2a and anti‐interferon‐α2a monoclonal antibody IgG as a model system, we successfully extracted the antigen protein and determined the approximate binding region for the antigen/antibody interaction (i.e., the tryptic fragment responsible). Copyright © 2001 John Wiley & Sons, Ltd.
Characterization of a [(O3/2SiMe)x(OSi(OH)Me)y(OSiMe2)z] silsesquioxane copolymer resin by mass spectrometry
Authors: Tecklenburg Ron E. , Wallace William E. , Chen Huiping
Published: August 2002

Electrospray ionization Fourier transform ion cyclotron resonance (ESI‐FTICR) mass spectrometry and matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry were applied to a complex silsesquioxane‐siloxane copolymer resin. The wide‐polydispersity starting material was fractionated into 21 separate fractions in order to facilitate the analysis by mass spectrometry. ESI‐FTICR exact mass measurements were able to identify the specific oligomers present in the lowest mass fractions and showed that very few unreacted silanol groups remained, that is, topologically closed structures predominated. MALDI‐TOFMS was able to show that gel‐permeation chromatography substantially underestimated the molecular masses of the higher mass fractions. Mass autocorrelation was able to show that the silsesquioxane monomer appeared only in even numbers in any given oligomer. This is a natural consequence of the highly condensed nature of the resin. Copyright © 2001 John Wiley & Sons, Ltd.
On‐target fraction collection for the off‐line coupling of capillary isoelectric focusing with matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Chartogne Anne , Gaspari Marco , Jespersen Sonja , Buscher Brigitte , Verheij Elwin , Heijden Robert van der , Tjaden Ubbo , Greef Jan van der
Published: August 2002

In the present work, we describe a collection system for the off‐line coupling of capillary isoelectric focusing (CIEF) with matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry. In this system, the capillary effluent is directly deposited in fractions onto the MALDI target via the use of a sheath liquid. The collected fractions are subsequently supplemented with matrix and further analysed by MALDI‐TOF mass spectrometry for mass assignment. The experimental set‐up includes a fiber optic based UV detector operating at 280 nm, which allows the study of the influence of the sheath liquid composition on the CIEF separation. The influence of the carrier ampholyte concentration on the protein MALDI spectra was also evaluated and the feasibility of the collection method was finally demonstrated with a mixture of four standard proteins. Copyright © 2002 John Wiley & Sons, Ltd.
Tandem mass spectra of tryptic peptides at signal‐to‐background ratios approaching unity using electrospray ionization high‐field asymmetric waveform ion mobility spectrometry/hybrid quadrupole time‐of‐flight mass spectrometry
Authors: Barnett David A. , Ding Luyi , Ells Barbara , Purves Randy W. , Guevremont Roger
Published: August 2002

High‐field asymmetric waveform ion mobility spectrometry (FAIMS) has been coupled to a quadrupole time‐of‐flight mass spectrometer for the tandem mass spectrometric analysis of tryptic peptides of pig hemoglobin. Using FAIMS, low levels (fmol/µL) of multiply charged tryptic peptides were separated from relatively intense chemical background such that their tandem mass spectra (MS/MS) lacked many background‐related fragment ions observed using a conventional ESI‐QqTOFMS instrument. Substantial improvements in both first‐order and tandem mass spectra were realized while maintaining approximately the same absolute intensities. Copyright © 2002 John Wiley & Sons, Ltd.
Robust control of multi‐axis magnetic bearing systems
Authors: Yeh T.‐J. , Chung Ying‐Jer , Wu Wei‐Chung
Published: August 2002

This paper proposes robust control schemes for multi‐axis magnetic bearing systems under current control and voltage control. The control schemes are based on a model which characterizes not only the electromagnetic interaction but also secondary effects such as flux leakage, fringing fluxes, and finite core permeance in the magnetic bearing. In the current control case, a sliding‐mode‐based robust controller, whose control parameters have to be deliberately chosen to account for the uni‐directionality of magnetic forces, is proposed to provide robust performance against uncertain dynamics. In the voltage control case, a control scheme that combines the sliding methodology and the backstepping technique is used to provide robust performance under the influence of the electrical dynamics. It is demonstrated through simulations and experiments that, because the nonlinearity and the uncertainty inherently residing in the system behaviour are directly tackled, the proposed controllers achieve superior tracking performances compared to control lers based on linearization. Copyright © 2001 John Wiley & Sons, Ltd.
Use of mesohabitat‐specific relationships between flow velocity and river discharge to assess invertebrate minimum flow requirements
Authors: Brunke Matthias , Hoffmann Andreas , Pusch Martin
Published: August 2002

The benthic macroinvertebrate community in the sixth order lowland River Spree (Germany) was investigated in order to assess ecological effects of a flow reduction. The benthic habitat was composed of visually distinguishable mesohabitats. Eight mesohabitats were delineated, Dreissena‐bank, unionid mussel bed, rip‐rap, coarse woody debris (CWD), alder roots, stable sand, shifting sand and mud. The mesohabitats differed in their physical structure and hydraulic nature. These functional habitats were partly inhabited by distinct invertebrate assemblages. The use of mesohabitat‐specific relationships between flow velocity and discharge seemed the most appropriate approach in order to assess the impact of flow reduction on lotic fauna. In combination with the species‐specific optima and tolerances for flow velocity, this approach can be used to develop a minimum flow level that mitigates the effects of flow reduction and enables the persistence of rheophilic invertebrates in their specific mesohabitat. Copyright © 2001 John Wiley & Sons, Ltd.
Understanding students' explanations of biological phenomena: Conceptual frameworks or p‐prims?
Authors: Southerland Sherry A. , Abrams Eleanor , Cummins Catherine L. , Anzelmo Julie
Published: August 2002

This study explores two differing perspectives of the nature of students' biological knowledge structures, conceptual frameworks, and p‐prims. Students from four grade levels and from three regions of the United States were asked to explain a variety of biological phenomena. Students' responses to the interview probes were analyzed to describe 1) patterns in the nature of students' explanations across grade levels and interview probes, and 2) the consistency of students' explanations across individual interview probes and across the range of probes. The results were interpreted from both perspectives of knowledge structures. While definitive assertions supporting either perspective could not be made, each hypothesis was explored. Although the more prevalent description of student conceptions within a broader conceptual framework could not be discounted, the p‐prim of need as a rationale for change was also found to offer a useful description of knowledge frameworks for this content area. The difficulties endemic to the use of biology for the study of basic knowledge structures are also discussed. © 2001 John Wiley & Sons, Inc. Sci Ed 85:328–348, 2001.
Charge writing on the nanometre scale in a fluorocarbon film
Authors: Mesquida P. , Knapp H. F. , Stemmer A.
Published: August 2002

By applying voltage pulses to an atomic force microscopy cantilever, nanometre‐scale charge patterns were written onto an electret surface consisting of a fluorocarbon layer grown by plasma‐enhanced chemical vapour deposition on substrates with different electric conductivities. Kelvin probe force microscopy then was used to assess quantitatively the parameters relevant for optimal charge storage properties. Pulse height and duration, layer thickness and substrate, as well as the surrounding media, were varied to optimize the size of the charge patterns and their lifetime. By applying pulses of 100 µs and 25 V, lifetimes of several days were achieved with 20 nm thick fluorocarbon layers on p‐doped silicon as the underlying substrate. Our process also allowed us to create localized charge patterns on metal substrates. Furthermore, for the first time, nanoscale charge patterns have been written in a liquid environment that can be used as carrier substance for particles. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of several methods to test for the existence of a monotonic dose–response relationship in clinical and epidemiological studies
Authors: Leuraud Klervi , Benichou Jacques
Published: August 2002

The Mantel‐extension chi‐square test for overall trend and an asymptotically equivalent test based on logistic regression are commonly used to test for a monotonic dose–response relationship between exposure and disease in epidemiological and clinical studies. However, these tests present two important disadvantages, as they (i) make the restrictive assumption of a parametric model of linear form on the logit scale and (ii) impose the a priori choice of scores to code for the exposure categories. Indeed, the linear assumption, if made incorrectly, can lead to an invalid conclusion, and the choice of scores lends arbitrariness to the test results. Some alternative tests have been proposed in the literature. We have considered several of these tests, namely one based on isotonic regression, the T‐test based on contrasts and a recently published test based on adjacent contrasts (Dosemeci–Benichou test). The aim of our study was to compare the statistical properties (type I error and power) of these tests and of the commonly used Mantel‐extension test for overall trend. We generated cohort and case‐control data and considered one‐ and two‐sided versions of the tests. Moreover, we studied the tests under the null hypothesis of no relationship between exposure and disease and under various alternative patterns of monotonic or non‐monotonic dose–response relationships. This study confirms that the commonly used trend tests can lead to erroneous conclusion of a monotonic dose–response relationship. The test based on isotonic regression does not represent a favourable alternative, as it tends to be too powerful in case of non‐monotonic dose–response relationship patterns. The tests based on contrasts seem to possess more favourable properties by combining close to nominal type I error, high power for monotonic alternatives and low power for non‐monotonic alternatives. Copyright © 2001 John Wiley & Sons, Ltd.
Asian American College Students Who Are Educationally at Risk
Authors: Yeh Theresa Ling
Published: August 2002

Asian Americans are often thought of as high academic achievers. However, there is an overlooked and growing population of Asian American students who are educationally at risk and may need additional programs and services to help them succeed in college.
Ultrastructural immunocytochemical localization of the dopamine D2 receptor and tyrosine hydroxylase in the rat ventral pallidum
Authors: Mengual Elisa , Pickel Virginia M.
Published: August 2002

The mesopallidal dopamine system plays a role in locomotor activity and reward. To understand the potential contribution of the dopamine D2 receptor (D2R) to the action of dopamine in the ventral pallidum (VP), we used electron microscopic immunocytochemistry to examine the cellular and subcellular localization of an antipeptide antiserum against the D2R in both ventromedial and dorsolateral VP compartments. In each region the majority of the total D2R‐labeled profiles (n = 1,132) were axon terminals (55%) and small unmyelinated axons (27%). These terminals were often apposed to other axon terminals or dendrites and formed almost exclusively symmetric, inhibitory‐type axodendritic synapses. Immunogold D2R labeling in axon terminals was seen on the plasmalemma and membranes of nearby synaptic vesicles. In ventral pallidal sections processed for dual detection of D2R peptide and the catecholamine‐synthesizing enzyme tyrosine hydroxylase (TH), D2R labeling was detected in a few axons and axon terminals containing TH immunoreactivity as well as in axons contacted by TH‐labeled terminals. In most cases, however, the D2R‐labeled profiles were located at a distance from small axons and terminals containing TH. Our results provide the first ultrastructural evidence that D2Rs in the two VP subterritories are strategically located for primary involvement in modulation of the presynaptic release of nondopaminergic inhibitory transmitters. They also suggest that in this region the presynaptic D2 receptors are 1) minimally involved in autoregulation of dopaminergic transmission, and 2) differentially activated by dopamine, depending in part on levels and distance from release sites. Synapse 43:151–162, 2002. © 2002 Wiley‐Liss, Inc.
Seismic isolation design of the Arrowhead Regional Medical Center
Authors: Asher J. W. , Young R. P. , Ewing R. D.
Published: August 2002

The Arrowhead Regional Medical Center, located in Colton, CA, consists of six separate building structures containing a total of approximately 920 000 square foot of floor space for hospital and support services. Five of the six buildings are base‐isolated. Each of the five base‐isolated buildings is of different size and configuration, ranging from a six‐storey, 360 000‐square‐foot curved‐front nursing tower to a two‐storey, 24 000‐square‐foot rectangular shaped central plant building. The building structures are framed with structural steel, utilizing concentric braced frames as the lateral force resisting system. The design ground motion for the site, which is located 3 km and 15 km from the San Jacinto and San Andreas faults, respectively, is very severe. A base‐isolation system has been designed for this facility that will provide essentially elastic building response to the design strong ground motion. The base‐isolation system is a hybrid passive energy dissipation system consisting of both linear and nonlinear and high damping rubber bearings along with viscous damping devices located at the base of the structure. The high damping rubber bearings provide both lateral stiffness, which governs the fundamental period of vibration of the system and hysteretic damping, while the viscous damping devices provide velocity‐dependent damping, which serves to control overall building displacements. This will maximize the probability that this essential facility will remain fully operational after a major earthquake. Design criteria, structural analysis and design methodologies, and construction details are presented and discussed. The response of one of the base‐isolated structures is calculated utilizing actual recorded ground motions from the 1994 Northridge Earthquake. Copyright © 2001 John Wiley & Sons, Ltd.
Improving Comprehension Through Discourse Processing
Authors: Graesser Arthur C. , Person Natalie K. , Hu Xiangen
Published: August 2002

Deep coherent explanations organize shallow knowledge and fortify learners for generating inferences, solving problems, reasoning, and applying their knowledge to practical situations.
Optimization of K‐shell intensity ratios in electron probe microanalysis
Authors: Castellano G. , Bonetto R. , Trincavelli J. , Vasconcellos M. , Campos C.
Published: August 2002

A method for refinement of atomic and experimental parameters was applied to the optimization of K‐shell intensity ratios in electron probe microanalysis (EPMA). This kind of procedure, previously used in x‐ray diffraction, is shown to be a powerful tool in EPMA. The method consists of minimizing the differences between an experimental x‐ray spectrum and a function proposed to account for the bremsstrahlung and characteristic peaks from the corresponding sample, and also for detection artifacts. In this work, the method was used for the determination of transition rates. This procedure was applied to 14 elements with atomic numbers ranging from 20 to 42. The results obtained are in agreement with theoretical and experimental data for Kα/(Kβ+ Kα) intensity ratios. In addition, Kα1, Kα2, Kβ1, and Kβ2relative intensities were compared with experimental data, showing a similar behaviour. Copyright © 2002 John Wiley & Sons, Ltd.
Yeast Lrg1p acts as a specialized RhoGAP regulating 1,3‐β‐glucan synthesis
Authors: Watanabe Daisuke , Abe Mitsuhiro , Ohya Yoshikazu
Published: August 2002

Selection of an extragenic suppressor of fks1‐1154 Δfks2, mutations in the catalytic subunits of yeast 1,3‐β‐glucan synthase (GS) conferring temperature‐sensitivity, led to the LRG1 gene, which was originally identified as a LIM‐RhoGAP homologous gene. Mutations in the LRG1 gene restore impaired 1,3‐β‐glucan synthesis in the fks1‐1154 Δfks2 mutant as well as that in rho1‐2, a temperature‐sensitive mutant of Rho‐type GTPase that functions as a regulatory subunit of GS. Two‐hybrid analyses of Lrg1p, which contains a sequence conserved among Rho GTPase‐activating proteins (GAPs), revealed its specific interactions with the active form of Rho1p. Among eight potential yeast RhoGAPs, Lrg1p is the only member that negatively regulates GS activity: mutations in the rest of GAPs, including bem2, Δbem3, Δsac7, Δbag7, Δrga1, Δrga2 and Δrgd1, do not suppress impairment of 1,3‐β‐glucan synthesis. Analyses of Mpk1p phosphorylation revealed the inability of Lrg1p to regulate the Pkc1p–MAP kinase cascade, a distinct Rho1p‐regulating signalling pathway known to be affected by the GAPs, Bem2p and Sac7p. Thus, different groups of Rho1p GAPs control the activity of different Rho1p‐effector proteins. Copyright © 2001 John Wiley & Sons, Ltd.
Role of the Nha1 antiporter in regulating K+ influx in Saccharomyces cerevisiae
Authors: Bañuelos María A. , Ruiz María C. , Jiménez Adriana , Souciet Jean‐Luc , Potier Serge , Ramos José
Published: August 2002

NHA1 encodes a K+ (Na+)/H+ antiporter in the plasma membrane of Saccharomyces cerevisiae. We report that cells expressing the NHA1 gene contained less K+ than the mutant lacking the gene when grown without K+ limitation. They also grew better at low K+ and showed higher affinity of transport than the nha1 strain. In agreement with the function of an electroneutral cation/H+ antiporter, the effect was only observed at acidic pH. The improved growth and transport depended on the presence of Trk1p (the main K+ influx system) and did not require the product of TRK2. We propose that Nha1p regulates the potassium content of the cell and, as a consequence, can affect the activity of the main K+ influx system (Trk1p). Copyright © 2002 John Wiley & Sons, Ltd.
Tools for the study of genome rearrangements in laboratory and industrial yeast strains
Authors: Lockhart Lesley , Oliver Stephen G. , Delneri Daniela
Published: August 2002

In order to investigate the extent of genome rearrangements in laboratory and industrial yeast strains, a set of plasmids, containing ca. 300 bp fragments from highly conserved genes from S. cerevisiae, has been constructed. We chose three unique PCR products, each from a single gene, per chromosome: one from close to the centromere, and one from each chromosome end. Using these plasmids as probes to hybridize a Southern blot from a pulsed‐field gel electrophoresis separation of the 16 yeast chromosomes, it is possible to identify large chromosomal rearrangements such as reciprocal translocations. Copyright © 2002 John Wiley & Sons, Ltd.
Chromosome V loss due to centromere knockout or MAD2‐deletion is immediately followed by restitution of homozygous diploidy in Saccharomyces cerevisiae
Authors: Zang Yuhui , Garrè Massimiliano , Gjuracic Kresimir , Bruschi Carlo V.
Published: August 2002

To investigate the possibility of inducing specific chromosome loss by centromere deletion in eukaryotic cells, the yeast diploid strain ZG1, carrying three pairs of heterozygous marker genes (CAN1S/can1R, URA3/Δura3, hphMX4/HIS1), widely spread on both arms of chromosome V, was constructed. One of the two centromeres V of ZG1 was replaced by the LEU2 gene via the well‐established PCR‐mediated knockout technique. After DNA transformation, putative yeast colonies that showed loss of heterozygosity (LOH) for the three markers of chromosome V (CAN1S URA3 hphMX4) were identified among the colonies selected for leucine prototrophy. Phenotypic tests, colony‐PCR and Southern blot analysis of these cells demonstrated the physical loss of the CAN1s, URA3, and hphMX4 marker genes from the genome. Further tetrad analysis results were consistent with this conclusion; however, four‐spore viability indicated a normal chromosome number of these transformants. To verify the diploidy of the selected chromosome V, the HIS1 gene was deleted with a standard KanMX4 knockout DNA cassette. The resulting heterogeneity of the HIS1/KanMX4 markers, together with quantitative PCR and densitometric analysis on chromosome V, confirmed its diploid complement, thereby indicating that an endoreduplication event had taken place. Restitution of diploidy also occurred in MAD2‐deleted strains undergoing higher rates of spontaneous chromosome V loss, indicating a more general phenomenon that is undetectable by phenotypic analysis alone. Copyright © 2002 John Wiley & Sons, Ltd.
Construction of FLAG tagging vectors for Candida albicans
Authors: Umeyama Takashi , Nagai Yuki , Niimi Masakazu , Uehara Yoshimasa
Published: August 2002

We have constructed three new vectors for Candida albicans (pFLAG–Act1, pFLAG–Mal2, and pFLAG–Met3). The proteins can be expressed as C‐terminal FLAG‐tagged proteins under the control of different promoters (ACT1, MAL2, and MET3). To confirm the protein expression, we used the Renilla reniformis luciferase and the drug efflux pump Cdr1p of Candida albicans as reporters. The luciferase protein expressed by the MET3 promoter was found to have the strongest activity of the three promoters when cultured in a methionine‐depleted synthetic medium. Cdr1p was expressed as a C‐terminal FLAG‐tagged protein using either these vectors or PCR‐mediated integration. The fluconazole resistance was increased by the Cdr1p expression in a CDR1 homozygous disruptant. The expressed proteins were detected by Western blotting using the anti‐FLAG antibody. We also constructed a Cdr1p–FLAG expressing strain, in which we directly tagged Cdr1p with FLAG on the genome loci, using a PCR‐based integrative marker cassette that was amplified using the pFLAG vector. We then confirmed the protein expression by Western blotting. Thus, these new vectors are useful as C. albicans genetic tools. Copyright © 2002 John Wiley & Sons, Ltd.
Characteristics of Infection with Candida Species inPatients with Necrotizing Pancreatitis
Authors: Isenmann Rainer , Schwarz Michael , Rau Bettina , Trautmann Matthias , Schober Wolfgang , Beger Hans G.
Published: August 2002

This study focuses on the relevance of Candida infection (albicans andnon‐albicans) in patients with necrotizing pancreatitis.Altogether, 92 patients with infected pancreatic necrosis were reviewedfor Candida infection. All patients underwent surgicalnecrosectomy for infected pancreatic necrosis. Data from patients withCandida growth in intraoperative smears were compared tothose obtained from patients without Candida infection.There were 22 patients (24%) with Candida infection.Patients with or without Candida infection were comparableregarding age, gender, etiology, and severity scores at admission.Candida patients suffered a higher mortality (64% vs.19%, p = 0.0001) and experienced more systemiccomplications (3.2 ± 1.6 vs. 2.1 ± 1.4; p= 0.004) than patients without Candida. Preoperativeantibiotics were given significantly longer prior toCandida infection (19.0 ± 13.2 vs. 6.4 ± 10.3days; p < 0.0001). With regard to the concomitantspectrum of bacteria, solitary gram‐negative infection was rare inCandida patients (5% vs. 43%, p =0.0006). The presence of Candida in patients with infectedpancreatic necrosis is associated with increased mortality. Our dataprovide evidence that application of antibiotics contributes to thedevelopment of Candida infection and to changes in thebacterial spectrum of infected necrosis with an increase in theincidence of gram‐positive infection.
Effects of Proximal Duodenal Transection and Anastomosis on Interdigestive Sphincter of Oddi Cyclic Motility in Conscious Dogs
Authors: Deng Zhou‐Lu , Nabae Toshinaga , Konomi Hiroyuki , Takahata Shunichi , Yokohata Kazunori , Ogawa Yoshiaki , Chijiiwa Kazuo , Tanaka Masao
Published: August 2002

Gallstones formed after gastrectomy are bilirubinate stones probably associated with biliary stasis and infection. Effects of proximal duodenal transection performed during gastrectomy on interdigestive sphincter of Oddi cyclic motility possibly relevant to this phenomenon were investigated in four conscious dogs. Although the cyclic change in sphincter motility was still in concert with the duodenal migrating motor complex after duodenal transection, the mean period was shortened (p < 0.02), and the frequency (p < 0.005) and amplitude (p < 0.001) of sphincter phasic waves during phase III were decreased. The cyclic variation of basal pressure disappeared, and the mean basal pressure throughout the cycle was significantly reduced (p < 0.003). Transient inhibition of sphincter and duodenal contractions normally seen during phase III disappeared. Duodenal transection reversed the response of the sphincter to cholecystokinin‐octapeptide from inhibition to stimulation and from reduction of the basal pressure to elevation. These data suggest that duodenal transection produces significant changes in interdigestive sphincter of Oddi motility, possibly contributing to augmented duodenobiliary reflux and then lithogenesis. Myoneural continuity between the stomach and sphincter of Oddi at the proximal duodenum may play an important role in maintaining normal biliary dynamics.
Optimal Surgery for Papillary Thyroid Carcinoma
Authors: Udelsman Robert , Lakatos Edward , Ladenson Paul
Published: August 2002

There has been a long, unresolved debate regarding the operation of choice for well differentiated carcinoma of the thyroid. We therefore analyzed the feasibility, scope, sample size, and length of follow‐up required to determine the optimal operation for papillary thyroid carcinoma. A statistical approach was used to design a randomized prospective trial comparing the endpoints of complications, recurrence, and cause‐specific mortality. A complication comparison trial is prohibitive owing to the large population required—approximately 12,000 randomized patients. A recurrence trial appears feasible based on sample size: approximately 360 to 800 patients with a 6 to 10‐year follow‐up. However, recurrence detection would be severely compromised in the lobectomy arm, and a unilateral lag‐time bias would occur. A cause‐specific mortality trial proves to be the least objectionable, although a large sample size (n= 3100) would be required. Such a trial is critically dependent on the ability to select an appropriate endpoint. A cause‐specific mortality trial proves to be the most objective and statistically valid endpoint.
Management of Mycobacterial Cervical Lymphadenitis
Authors: Kanlikama Muzaffer , Gökalp Avni
Published: August 2002

The treatment results of mycobacterial cervical lymphadenitis in 69 patients between 1990 and 1993 are
reviewed. All patients underwent surgical procedures consisting of
total excision or selective nodal dissection for lymphadenopathies and
curettage for fluctuant cases, followed by antituberculous chemotherapy
applied according to the likely or proved mycobacterial species. For
this purpose, three or four drugs (including isoniazid, rifampin, ethambutol, and streptomycin) were used for 12 to 18 months. The cure
rate was 100% after a minimum follow‐up of 3 years. Clinical features, treatment modes, and guidelines for management are discussed.
Prospective Evaluation of Parathyroid Graft Function after Total Parathyroidectomy and Heterotopic Autotransplantation in Renal Hyperparathyroidism by Bilateral Determination of Intact Parathormone in Cubital Venous Blood
Authors: Walgenbach Siegfried , Hommel Gerhard , Junginger Theo
Published: August 2002

The value of gradients for intact parathyroid hormone (PTH) in the assessment of graft function after total parathyroidectomy/autotransplantation for renal hyperparathyroidism was evaluated in a prospective follow‐up study. Altogether 99 patients who underwent operation from August 1, 1987 to December 31, 1996 were prospectively investigated and reexamined postoperatively, including analyses of serum calcium, alkaline phosphatase, and intact PTH in the antecubital venous blood of both arms. The postoperative course is known for all patients. Of the 99 patients included in the study, 95 underwent one to nine reexaminations (median three) over follow‐up periods of 1 month to 5 years (median 24 months). Reproducible PTH gradients were established during follow‐up. Ninety percent of the calculated gradients were ≤ 20. Intermittent postoperative hypocalcemia, due to calcium deficiency of the skeleton in renal osteopathy, led to an increase in PTH secretion and gradients. Increasing gradients > 20 during follow‐up make graft‐dependent recurrence probable. The presence of a gradient of approximately 1 in bilaterally elevated PTH levels may be an indication of hyperfunctioning parathyroid tissue in the neck or mediastinum. The combined assessment of the course of gradients for intact PTH, hormone levels in both arms, and serum calcium permits an objective evaluation of parathyroid graft function.
Advances in Therapeutic Endoscopic Treatment of Common Bile Duct Stones
Authors: Seitz Uwe , Bapaye Amol , Bohnacker Sabine , Navarrete Claudio , Maydeo Amit , Soehendra Nib
Published: August 2002

Advances in cannulation techniques and instruments have helped in difficult bile duct cannulation and thus stone extraction. For small common bile duct (CBD) stones, endoscopic papillary balloon dilatation has been proposed as an alternative to endoscopic papillotomy (EPT). The technique must undergo further evaluation before recommending its routine use. For most patients with bile duct stones, EPT remains the method of choice. Out of 8204 patients treated in three surgical endoscopy centers (Chile, Germany, and India), 86% to 91% of all CBD stones could be extracted subsequently after EPT using a Dormia basket; 4% to 7% required mechanical lithotripsy (ML) before removal and 3% to 10% of the patients needed other sophisticated techniques, such as electrohydraulic lithotripsy (EHL), laser‐induced shock‐wave lithotripsy (LISL), or extracorporeal shock‐wave lithotripsy (ESWL). The local expertise and availability of equipment determines the choice of method used. In general, EHL or LISL is used for impacted CBD stones including stones in Mirizzi syndrome refractory to ML. ESWL is best suited for intrahepatic stones. Permanent stenting can be offered to poor risk patients instead of extensive procedures to clear the bile duct. Using currently available nonsurgical techniques, fewer than 1% of all patients with bile duct stones still require surgical intervention.
Long‐term Survival after Resection of Proximal Bile Duct Carcinoma (Klatskin Tumors)
Authors: Gerhards Michael F. , van Gulik Thomas M. , Bosma Anne , ten Hoopen‐Neumann Helgard , Verbeek Paul C.M. , Gonzalez Gonzalez Dionisio , de Wit Laurens T. , Gouma Dirk J.
Published: August 2002

This retrospective study in 79 surgically treated patients with a proximal bile duct carcinoma revealed 12 patients with a median age of 59.5 years (range 21–73 years) who survived more than 5 years. These 12 patients were analyzed to identify specific patient characteristics for long‐term survival. Fifteen patients died from postoperative complications and were excluded from this survival analysis. In relation with preoperative Bismuth classification, there were 3 (20%) long‐term survivors of 15 patients with type I tumors and 9 (35%) long‐term survivors of 26 patients with type II tumors. In the group of type III and IV tumors, there were no long‐term survivors. Concerning the type of resection, 9 of 51 (18%) patients had long‐term survival after local resection and 3 of 13 (23%) patients after local resection combined with hemihepatectomy. Complete tumor‐free surgical specimen margins were found in only 4 of 64 cases (6%), among which only one patient survived more than 5 years. Negative proximal bile duct margins, absence of multifocality, and diploid tumors showed a significant correlation with long‐term survival. There was no significant correlation between long‐term survival and postoperative radiotherapy. Of the 12 long‐term survivors, 5 died after 5 years: 2 had developed metastases and 1 a local recurrence; the other 2 died of a metastasis of an ovarian adenocarcinoma and cachexia, respectively. The remaining seven patients were still alive at the completion of this study. The mean survival of the 64 patients analyzed in this study (in which hospital mortality was excluded) was 33.7 months, with a median survival of 18.8 months. In conclusion, the preoperative Bismuth classification of the tumor, absence of multifocality, diploid‐type tumors, and negative proximal bile duct margins at histopathologic examination were the only significant prognostic factors for long‐term survival.
Thoracoscopic Surgery for Pulmonary Tuberculosis
Authors: Yim Anthony P.C. , Izzat Mohammad Bashar , Lee Tak Wai
Published: August 2002

Tuberculosis historically was a major impetus for the development of thoracic surgery, and it remains a serious health problem of global proportion. Thoracoscopy was first introduced at the turn of this century for closed chest adhesiolysis as an adjunct to collapse therapy for treatment of tuberculosis. This indication became obsolete with the discovery of streptomycin during the 1940s; and for a long time since then thoracoscopy was used only sporadically for the diagnosis of pleural disease. However, over the last few years, modern video‐assisted thoracoscopic surgery (VATS) has provided a new approach to the management of pulmonary tuberculosis. Over the last 5 years we have used VATS for diagnosis or treatment (or both) of 62 patients with pulmonary tuberculosis, including 20 pleural biopsies, 8 decortications, 17 wedge lung resections, 8 drainages of empyema, and 9 lobectomies. There was no surgical mortality, and complications were few. We conclude that VATS provides a safe, effective diagnostic modality (pleural biopsy, wedge resections) and therapeutic modality (decortications, drainage of empyema) for selected patients with pulmonary tuberculosis.
Surgery for Chronic Thromboembolic Pulmonary Hypertension
Authors: Hartz Renee S.
Published: August 2002

The modern era of surgery for chronic thromboembolic pulmonary hypertension (CTEPH) began just over 10 years ago. Until that time pulmonary thromboendarterectomy (PTE) was performed infrequently and essentially at a single medical center (University of California at San Diego—UCSD). It posed a formidable technical challenge and was associated with both high operative mortality (> 20%) and excessive morbidity due to respiratory and multiorgan system failure. Currently PTE is performed at numerous medical centers throughout the world, largely due to the pioneering efforts of those surgeons who developed and perfected the operation at UCSD. Operative mortality rates have fallen, and postoperative complications have become less common. Although no longer simply an autopsy curiosity, CTEPH continues to be an underdiagnosed condition. Increased awareness and better diagnosis will lead to curative surgery in more patients worldwide.
Lung Transplantation: Current Status and Future Prospects
Authors: Meyers Bryan F. , Patterson G. Alexander
Published: August 2002

Lung transplantation recently marked its 35th anniversary. The period has been marked by 20 years of initially slow progress followed by 15 years of explosive growth and success. In 1997 the number of lung and heart‐lung transplants exceeded 1000 in the United States and 1400 worldwide. Current 1‐year survival exceeds 75% for most diagnoses. Functional results are excellent and durable with first second expired volume (FEV1) improving from 15% to 20% of the predicted normal preoperatively to 75% to 80% of the predicted normal postoperatively in most diagnoses. Problems facing lung transplant programs during the next century include the unavailability of graft lung donors, technical limitations of explanted graft lung preservation, and the prevention and treatment of bronchiolitis obliterans syndrome. Current status and future trends for lung transplantation are reviewed.
Tumors of the Rectum and Anal Canal
Authors: Hatch Kathryn F. , Blanchard D. Kay , Hatch George F. , Wertheimer‐Hatch Laura , Davis Gregory B. , Foster Roger S. , Skandalakis John E.
Published: August 2002

This collective review includes all available case reports of smooth muscle (stromal) tumors of the rectum and anal canal in the world literature. When compiling this review we endeavored to present cumulative and recently collected data of both benign and malignant smooth muscle tumors found in the literature spanning the period from 1881 to 1996, which totaled 432 leiomyomas (LMs) and 480 leiomyosarcomas (LMSs) of the anus and rectum. The peak age of frequency for LMs was 40 to 59 years and 50 to 69 years for LMSs; men were slightly more likely to develop both benign and malignant anorectal smooth muscle tumors than women. Intraluminal growth of both LMs and LMSs was more frequently seen than extraluminal or intramural patterns, and tumors were more likely to be found in the rectum than in the anus. Patients with LMs presented most commonly with gastrointestinal (GI) bleeding, a palpable mass, or anorectal pain. As with smooth muscle tumors in other areas of the alimentary tract, symptoms likely persisted for less than 1 year prior to diagnosis. As was also the case for these neoplasms in other GI locations, LMSs tended to be larger than LMs. Approximately 20% of LMSs reported from 1881 to 1996 had metastasized at diagnoses. The local recurrence rate for resectable tumors was more than 80%, exceeding the propensity of LMSs in other areas of the GI tract to recur.
The Clinical, Cerebrospinal Fluid, and Histopathologic Effects of Epidural Ketorolac in Dogs
Authors: Gallivan Sean T. , Johnston Spencer A. , Broadstone Richard V. , Jortner Bernard S. , Reimer Michele
Published: August 2002

Objective—To evaluate the clinical, cerebrospinal fluid (CSF), and histopathologic effects of epidural ketorolac.

Study Design—Blinded, randomized, placebo controlled study.

Animals—Twenty‐two adult mixed breed dogs with 16 treatment and 6 control dogs, weighing 14.4 to 29.8 kg.

Methods—Dogs were anesthetized and epidural catheters were placed at the lumbosacral space. Catheter placement was evaluated fluoroscopically. Ketorolac (0.4 mg/kg) or placebo (5% ethanol) was administered epidurally over a 52‐hour period, with 5 injections given at 12‐hour intervals. At 1, 2, 4, or 8 hours after the first and last injection of ketorolac, dogs were anesthetized and CSF was obtained. Control dogs had CSF sampled 1 hour after the first and last ethanol injection. Neurologic function and pain responses were evaluated before and during the study. Selected dogs were then killed and necropsies performed.

Results—None of the dogs exhibited any clinical or neurologic abnormalities during the study. No statistical difference was noted in pain response or CSF analysis between treatment and control dogs. Gross necropsy revealed gastrointestinal ulceration of varying degrees in all treatment dogs. Histopathologic analysis of the spinal cord and meninges revealed minimal focal leptomeningeal phlebitis in 2 of 8 treatment dogs and minor subdural inflammation in 1 control dog. No changes to the neural structures were noted in any dogs.

Conclusions—Epidural administration of ketorolac did not cause clinical signs, alteration in CSF values, or pathologic changes to the spinal cord when used for short duration. Gastrointestinal ulceration was common when ketorolac was administered epidurally at 0.4 mg/kg every 12 hours for 5 treatments.

Clinical Relevance—This study documented the neurologic safety of epidural ketorolac in dogs before an efficacy trial can be performed. Gastrointestinal ulceration may limit use to short duration or a single injection.
Accuracy of Radiography, Nuclear Scintigraphy, and Histopathology for Determining the Proximal Extent of Distal Radius Osteosarcoma in Dogs
Authors: Leibman Nicole F. , Kuntz Charles A. , Steyn Phillip F. , Fettman Martin J. , Powers Barbara E. , Withrow Stephen J. , Dernell William S.
Published: August 2002

Objective—To compare the accuracy of radiography, nuclear scintigraphy, and histopathology for determining the proximal extent of distal radius osteosarcoma in dogs.

Study Design—Retrospective clinical study.

Sample Population—Twenty client‐owned dogs taken to Colorado State University with osteosarcoma of the distal radius.

Methods—Medical records of 20 dogs with confirmed osteosarcoma that underwent a limb‐salvage procedure were reviewed. Measurements were performed directly from the lateral view of each radius, from both the scintigram and the radiograph, to determine the length of the radius and the distance from the proximal extent of the tumor to the distal radiographic or scintographic extent of the radius. The ratio of distal radial involvement to total radius length was calculated. A similar ratio was also determined using the macroslide, which included the entire portion of bone that was excised during the limb‐salvage procedure. All 3 methods of measurement were compared.

Results—Nuclear scintigraphy significantly overestimated tumor length when compared with macroslide specimen measurements. Radiography also overestimated tumor length, but these results were not significantly different from macroslide specimen measurements.

Conclusions—Both radiography and nuclear scintigraphy overestimate the extent of distal radiaus osteosarcoma in dogs when compared with histopathologic macroslides of the same lesions. Nuclear scintigraphy overestimated tumor extent to a larger degree than did radiography.

Clinical Relevance—Although radiography is a more accurate method of measurement of the extent of distal radius osteosarcoma, because nuclear scintigraphy overestimates tumor length to a greater degree, scintigraphy may provide a larger margin of safety for determining the site of proximal osteotomy during a limb‐salvage procedure. However, caution should be taken when utilizing scintigraphy, because this method may overestimate length of radius involved to such an extent as to cause the surgeon to believe that a patient is not a suitable limb‐salvage candidate.