bluuebunny/crossref_metadata_2025 huggingface dataset:
Complete imputation of missing repeated categorical data: one‐sample applications
Authors: West Colin P. , Dawson Jeffrey D.
Published: August 2002

Longitudinal studies with repeated measures are often subject to non‐response. Methods currently employed to alleviate the difficulties caused by missing data are typically unsatisfactory, especially when the cause of the missingness is related to the outcomes. We present an approach for incomplete categorical data in the repeated measures setting that allows missing data to depend on other observed outcomes for a study subject. The proposed methodology also allows a broader examination of study findings through interpretation of results in the framework of the set of all possible test statistics that might have been observed had no data been missing. The proposed approach consists of the following general steps. First, we generate all possible sets of missing values and form a set of possible complete data sets. We then weight each data set according to clearly defined assumptions and apply an appropriate statistical test procedure to each data set, combining the results to give an overall indication of significance. We make use of the EM algorithm and a Bayesian prior in this approach. While not restricted to the one‐sample case, the proposed methodology is illustrated for one‐sample data and compared to the common complete‐case and available‐case analysis methods. Copyright © 2002 John Wiley & Sons, Ltd.
Cure model analysis in cancer: an application to data from the Children's Cancer Group
Authors: Sposto Richard
Published: August 2002

The most commonly used statistical methods for evaluating treatment or prognostic effects on cancer outcome – the logrank test and Cox regression analysis – rely on the proportional hazards (PH) assumption in that they have maximal power in this circumstance. Implicitly, these methods emphasize covariate effects on failure times rather than their effects on the proportion of long‐term survivors (‘cures’), which may be of equal or primary interest. In paediatric cancer, treatment has progressed dramatically in recent decades, and in many diagnoses cures are obtained in a large fraction of patients. A primary focus of clinical research is therefore the achievement of cure. Parametric cure model (PCM) analysis, introduced 50 years ago, is arguably better suited to the analytic requirements of clinical research in paediatric and other cancers where cure is achieved. In this paper two classes of PCMs are described and used to analyse examples from the Children's Cancer Group. These are compared to analyses using Cox regression analysis. Results from PCM analyses are similar or identical to Cox regression analysis when the PH assumption is appropriate. When it is not, PCMs can provide a coherent way to investigate and report covariate effects on the proportion cured separately from their effect on time to failure. Despite their reliance on explicit parametric forms, PCMs often provide a good description of cancer outcome, and are insensitive to lack of fit provided that follow‐up is sufficient. Copyright © 2002 John Wiley & Sons, Ltd.
Stress levels in nursing staff working in oncology
Authors: Escot C. , Artero S. , Gandubert C. , Boulenger J. P. , Ritchie K.
Published: August 2002

Care of cancer patients may be a source of considerable stress. As part of a large scale longitudinal study of the interaction of biological, psychological and environmental factors in determining patient outcome, the mental and physical health status of 37 members of the nursing staff of a cancer hospital was examined. The study identifies risk factors for stress, professional ‘burn‐out’ and psychiatric morbidity. An assessment questionnaire also examined work time, work organization, relationships with colleagues, identification of stressful situations, and treatment of pain. Each subject completed three scales designed to measure stress and psychiatric morbidity: the Nursing Stress Scale, the Maslasch Burnout Inventory and the General Health Questionnaire. Item analysis suggested that stress is primarily related to inadequate training, lack of time to deal with the psychological component of care giving especially terminal care, and relationship difficulties with other medical staff. Multiple analysis of correspondence indicated that in the face of stress, risk factors for professional burnout are high psychiatric symptomatology, lack of information at the time of diagnosis, poor perceived health, relationship difficulties with patients and their families, and work uncertainties. Copyright © 2001 John Wiley & Sons, Ltd.
Cognitive processes involved in the appraisal of stress
Authors: Guillet Laurent , Hermand Danièle , Mullet Etienne
Published: August 2002

Four experiments were organized around a central question: What is the form of relationship between estimated stress level on the one hand and situation strain, personal resources and social support, on the other? The first experiment examined the form of the relationship between estimated level of stress, situation strain and personal resources. The participants were students. They integrated situation strain and personal resources information in a non‐additive way. In particular, the effect of personal resources on the estimated level of stress varied as a function of the level of situation strain considered. When the situation strain was low, the stress level related with this circumstance largely depended on the personal resources of the individual. When the situation strain was high, the stress level related with this circumstance was much less dependent on the personal resources of the individual. The second experiment replicated these results among first‐aid workers, fire‐fighters and persons that had recently been injured. The third and fourth experiments replicated these results in various conditions differing as regards the level of social support. Copyright © 2002 John Wiley & Sons, Ltd.
Finding the right mix: franchising, organizational learning, and chain performance
Authors: Sorenson Olav , Sørensen Jesper B.
Published: August 2002

Franchising provides an increasingly important vehicle for entrepreneurial wealth creation and accounts for a large and growing share of business in the retail and service sectors. Chains—which operate in dispersed markets—most frequently use this form of governance. These firms must balance the centralization and standardization required for efficiency with the adaptation needed for success in varied local markets. By adopting an organizational learning perspective, we argue that the mix of company‐owned and franchised units affects this balance, thereby influencing chain performance. In particular, the different incentives facing company managers and the entrepreneurs that manage franchises encourage distinct patterns of organizational learning. Franchised establishments provide better opportunities for the firm to learn through experimentation; however, companies find it easier to diffuse this information and enforce standards through their company‐owned units. Analyses of franchised restaurant chains in the United States provide empirical evidence of this trade‐off. Copyright © 2001 John Wiley & Sons, Ltd.
The effects of CEO equity ownership and firm diversification on risk taking
Authors: Eisenmann Thomas R.
Published: August 2002

This research explores the effects of CEO equity ownership and corporate diversification on firms' risk‐taking and risk avoidance behaviors. Hypotheses regarding these effects are tested through econometric analysis of mergers in the U.S. cable television industry. Risk taking and avoidance are measured as horizontal expansion through acquisitions and as the divestiture of assets, respectively, in the face of increasing environmental turbulence. Copyright © 2002 John Wiley & Sons, Ltd.
Activity theory and the design of educational systems: examining the mediational importance of conversationa
Authors: Jenlink Patrick M.
Published: August 2002

Educational systems design, largely communicative in nature, depends on discourse as a semiotic tool for mediation within the cognitive, cultural, and creative activities essential to overcoming deep sociohistorical patterns woven into the fabric of society. The use of activity theory as a framework for understanding the mediational importance of conversation in educational systems design represents a sociocultural and inquiry‐oriented perspective that illuminates the relationship of design as a human activity system and the sociocultural context in which the design activity unfolds. As in Banathy's idealized concept of social systems design the importance of conversation is acknowledged in activity theory. Likewise, the importance of language as a symbol‐based mediational tool connects systems design and activity theory. Essential to the design of human activity systems, such as educational systems, is the ability of participants to acknowledge the dialectical contradictions that have emerged in their past or present activity system(s), while also acknowledging the importance of creating dialogical relationships toward the goal of designing new systems.

Design conversation and systems language underlie the socially constructed process of educational systems design. The framework of activity theory suggests that mediational artifacts such as language and discourse do not exist inside or outside of individual consciousness; rather they reside on the borderline between oneself as designer and the others who are also designers and users. From this perspective one has to take and use cultural artifacts (i.e., design conversation and systems language), to appropriate these artifacts with the intentions of the designer and the design community.

This paper will examine the mediational importance of conversation in the design of human activity systems that are educative and intentioned as learning systems. The paper will first examine activity theory and human activity systems, seeking to make connections between the systemic nature of activity theory as drawn from sociocultural learning theory and human activity systems grounded in social systems design. The paper will then examine educational systems design, viewing design as post‐epistemological in nature. Design conversation is then deconstructed to create an understanding of how this type of discourse draws from other genres or types of discourse such as dialogue, discussion, dialectic, ethical and critical discourse. The paper will then elaborate on design conversation as activity through an activity theory framework, demonstrating the dynamic relationship between participants, purpose, mediational artifacts, community, design work, and sociocultural rules governing design. The author will conclude with reflections on the mediational importance of design conversation in transcending dualisms that challenge social change. Copyright © 2001 John Wiley & Sons, Ltd.
Relationship between blockade of dopamine transporters by oral methylphenidate and the increases in extracellular dopamine: Therapeutic implications
Authors: Volkow Nora D. , Wang Gene‐Jack , Fowler Joanna S. , Logan Jean , Franceschi Dinko , Maynard Laurence , Ding Yu‐Shin , Gatley Samuel J. , Gifford Andrew , Zhu Wei , Swanson James M.
Published: August 2002

Methylphenidate (Ritalin) is an effective drug in the treatment of attention deficit hyperactivity disorder. However, the doses required therapeutically vary significantly between subjects and it is not understood what determines these differences. Since methylphenidate's therapeutic effects are in part due to increases in extracellular DA secondary to blockade of dopamine transporters (DAT), the variability could reflect differences in levels of DAT blockade. Here we used PET to assess if for a given dose of methylphenidate the differences in DAT blockade account for the variability in methylphenidate‐induced increases in extracellular DA. Ten healthy adult subjects were tested before and 60 min after oral methylphenidate (60 mg) with PET to estimate DAT occupancy (with [11C]cocaine as the radioligand) and levels of extracellular DA (with [11C]raclopride as the D2 receptor radioligand that competes with endogenous DA for binding to the receptor). Methylphenidate significantly blocked DAT (60 ± 11%) and increased extracellular DA in brain (16 ± 8% reduction in [11C]raclopride binding in striatum). However, the correlation between methylphenidate‐induced DAT blockade and DA increases was not significant. These results indicate that for a given dose of methylphenidate, individual differences in DAT blockade are not the main source for the intersubject variability in MP‐induced increases in DA. This finding suggests that individual differences in response to MP are due in part to individual differences in DA release, so that for an equivalent level of DAT blockade, MP would induce smaller DA changes in subjects with low than with high DA cell activity. Synapse 43:181–187, 2002. © 2002 Wiley‐Liss, Inc.
Effects of fasting and intermittent fasting on rat hepatocarcinogenesis induced by diethylnitrosamine
Authors: Rocha Noeme Sousa , Barbisan Luís Fernando , de Oliveira Maria Luiza Cotrim , de Camargo João Lauro Viana
Published: August 2002

The influences of fasting on DEN‐initiation and of intermittent fasting (IF) on the rat liver chemical carcinogenesis process were evaluated in a 52‐week long assay. Three groups of adult male Wistar rats were used: Groups 1 to 3 were treated with a single i.p. injection of 200 mg/kg of diethylnitrosamine (DEN). Group 2 was submitted to 48 h fasting prior to DEN treatment. After the 4th week, Group 3 was submitted to IF, established as 48 h weekly fasting during 48 weeks, while Groups 1 and 2 were fed ad libitum until the 52nd week. All animals were submitted to 70% partial hepatectomy and sacrificed at the 3rd and 52nd weeks, respectively. Fasting prior to DEN‐initiation did not influence the development of altered foci of hepatocytes (AFHs) and of hepatic nodules (Group 2 vs. Group G1). IF inhibited the development of preneoplastic lesions, since this dietary regimen decreased the number and the size of glutathione S‐transferase (GST‐P) positive foci and the number and size of liver nodules (Group G3 vs. Group G1). The inhibitory effect of IF was also reflected in the development of clear and basophilic cell foci. These results indicate that long‐term IF regimen exerts an anti‐promoting effect on rat hepatocarcinogenesis induced by DEN. Teratogenesis Carcinog. Mutagen. 22:129–138, 2002. © 2002 Wiley‐Liss, Inc.
Versatility and specificity in flavoenzymes: Control mechanisms of flavin reactivity
Authors: Miura Retsu
Published: August 2002

Flavoenzymes are characterized by their remarkable versatility and strict specificity. The former can be grasped when flavoenzymes are treated as a whole, while the latter refers to each flavoenzyme in which the broad versatility of flavin is specifically controlled. The versatility stems from the variety of the redox, ionic, and electronic states that the flavin ring system can adopt. Versatility of flavoenzymes is reflected in their classification, which has generally been based on substrates and reactions catalyzed. A different classification is presented according to the number of electrons transferred in the reductive and oxidative half reactions. Specificity of each flavoenzyme is understood in terms of the regulatory mechanism of the broad reactive potentiality of flavin. The elements of this regulatory mechanism include hydrogen‐bonding network, electrostatic effect, charge‐transfer interaction, positioning between a substrate/ligand and flavin, and modulation of resonance hybridization, each of which is explained with relevant examples provided mainly by studies from the author’s group. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:183–194, 2001
Transformation of organic molecules on the low‐valent {M(Ph2PCH2CH2PPh2)2} moiety derived from trans‐[M(N2)2(Ph2PCH2CH2PPh2)2] or related complexes (M = MO, W)
Authors: Seino Hidetake , Mizobe Yasushi , Hidai Masanobu
Published: August 2002

A zero‐valent {M(Ph2PCH2CH2PPh2)2} moiety (M = Mo, W) generated in situ by dissociation of the N2 ligands in trans‐[M(N2)2(Ph2PCH2CH2PPh2)2] can activate π‐accepting organic molecules including isocyanides and nitriles, which undergo the electrophilic attack caused by a strong π‐donation from a zero‐valent metal center. Cleavage of a variety of C–X bonds (X = H, C, N, O, P, halogen) also occurs at their electron‐rich sites through oxidative addition to form reactive intermediates, which subsequently degradate to yield smaller molecules either bound to or dissociated from the metal center. The mechanism is substantiated unambiguously by isolation of numerous intermediate stages. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:349–361, 2001
Use of imposex (pseudohermaphroditism) as indicator of the occurrence of organotin compounds in Portuguese coastal waters—Sado and Mira estuaries
Authors: Pessoa M. F. , Fernando A. , Oliveira J. S.
Published: August 2002

Organotin compounds, including tributyltin (TBT), are a class of the most toxic xenobiotics occurring in aquatic systems. High concentration levels in waters and sediments are mainly due to their extensive use as biocides and high persistence when present in sediments under anaerobic conditions. Toxicity studies have revealed the acute effects of TBT for aquatic organisms at concentrations as low as 1 μg/L, and the induction of imposex at levels below 0.5 ng/L TBT (as Sn). At 20 ng/L TBT (as Sn) causes sterility and is followed with the disappearance of the most sensitive neogastropods on a given shore. Imposex is the most sensitive response of all known pathological conditions for nontarget organisms following an exposure to tributyltin. In this study results are discussed that were obtained from two monitoring sites with different anthropogenic background using imposex monitoring as an indicator of TBT concentrations, as well as chemical analysis of tissue ofHinia (=Nassarius) reticulata(L.) (Gastropoda). © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 234–241, 2001
Supply Chain Environmental Management
Authors: Lippman Steve
Published: August 2002

Working with suppliers to manage environmental issues can yield significant advantages. But obstacles to
effective SCEM still remain. © 2001 John Wiley & Sons, Inc.
Channel estimation in narrowband wireless communication systems
Authors: Arslan Hüseyin , Bottomley Gregory E.
Published: August 2002

Channel estimation is an integral part of standard adaptive receiver designs used in narrowband, digital wireless communication systems. In this tutorial paper, commonly used approaches to channel estimation are reviewed. Both time‐invariant and time‐varying channels are considered. For time‐varying channels, both pilot symbol interpolation and data‐directed channel tracking are considered. Applications include the Global System for Mobile communications, the Enhanced Data rates for Global Evolution system, and another Time‐Division Multiple‐Access system known as Telecommunications Industry Association/Electronics Industry Association/Interim Standard—136 (TIA/EIA/IS‐136 or IS‐136). Copyright © 2001 John Wiley & Sons, Ltd.
A survey of multiuser/multisubchannel detection schemes based on recurrent neural networks
Authors: Engelhart Achim , Teich Werner G. , Lindner Jürgen , Jeney Gábor , Imre Sándor , Pap László
Published: August 2002

Multiuser/multisubchannel detection schemes based on a recurrent neural network (RNN) structure are a promising alternative to conventional detection schemes, both in terms of performance and complexity. This paper gives an overview of different approaches that make use of the results of RNN research for multiuser/multisubchannel detection. The detectors' results are compared with the results of conventional detection schemes in simulations of the uplink of a DS‐CDMA packet transmission system. Copyright © 2002 John Wiley & Sons, Ltd.
Resource management in power‐controlled cellular wireless systems
Authors: Xiao Mingbo , Shroff Ness B. , Chong Edwin K. P.
Published: August 2002

The efficient management of wireless resource is essential to the success of wireless systems. While power control is traditionally considered as a means to counteract the detrimental effects of channel fading, it is also a flexible mechanism to provide Quality of Service to individual users, and can be used as a platform for radio resource management. In this paper, we review the developments of distributed power control and related resource management problems in cellular wireless systems. We highlight the feasibility issue in a power‐controlled system, which enables us to push the system toward high efficiency, and prevent the system from collapsing at the same time. Considering the unique features of multimedia traffic to be supported in future wireless systems, we also review power and rate control schemes proposed for wireless data, and present a framework for utility‐based power control as a possible candidate for distributed power control of multimedia wireless systems. Copyright © 2001 John Wiley & Sons, Ltd.
A single‐copy suppressor of the Saccharomyces cerevisae late‐mitotic mutants cdc15 and dbf2 is encoded by the Candida albicansCDC14 gene
Authors: Jiménez Javier , Cid Víctor J. , Nombela César , Sánchez Miguel
Published: August 2002

The Saccharomyces cerevisiae CDC15, DBF2, TEM1 and CDC14 genes encode regulatory proteins that play a crucial role in the latest stages of the M phase of the cell cycle. By complementation of a S. cerevisiae cdc15‐lyt1 mutant with a Candida albicans centromeric‐based genomic library, we have isolated a homologue of the protein phosphatase‐encoding gene CDC14. The sequence analysis of the C. albicans CDC14 gene reveals a putative open reading frame of 1626 base pairs interrupted by an intron located close to the 5′ region. Analysis of C. albicans cDNA proved that the intron is processed in vivo. The CaCDC14 gene shares 49% of amino acid sequence identity with the S. cerevisiae CDC14 gene, 46% with Schizosaccharomyces pombe homologue, 35% with Caenorhabditis elegans and 37% and 38% with human CDC14A and CDC14B genes, respectively. As expected, the C. albicans CDC14 gene complemented a S. cerevisiae cdc14‐1 mutant. We found that this gene was able to efficiently suppress not only a S.cerevisiae cdc15‐lyt1 mutant but also a dbf2‐2 mutant in a low number of copies and allowed growth, although very slightly, of a tem1 deletant. Overexpression of the human CDC14A and CDC14B genes complemented, although very poorly, S. cerevisiae cdc15‐lyt1 and dbf2‐2 mutants, suggesting a conserved function of these genes throughout phylogeny. The sequence of CaCDC14 was deposited in the EMBL database under Accession No. AJ243449. Copyright © 2001 John Wiley & Sons, Ltd.
Cassettes for PCR‐mediated construction of green, yellow, and cyan fluorescent protein fusions in Candida albicans
Authors: Gerami‐Nejad Maryam , Berman Judith , Gale Cheryl A.
Published: August 2002

We have developed a set of plasmids containing fluorescent protein cassettes for use in PCR‐mediated gene tagging in Candida albicans. We engineered YFP and CFP variants of the GFP sequence optimized for C. albicans codon usage. The fluorescent protein sequences, linked to C. albicans auxotrophic marker sequences, were amplified by PCR and transformed directly into yeast. Gene‐specific sequence was incorporated into the PCR primers, such that the tag‐cassette integrates by homologous recombination at the 3′‐end of the gene of interest. This technique was used to tag Cdc3 and Tub1 with GFP, YFP and CFP, which were readily visualized by fluorescence microscopy and localized as expected. In addition, Tub1–YFP and Cdc3–CFP were visualized in the same cells. Thus, this technique directs one‐step construction of multiple fluorescent protein fusions, facilitating the study of protein co‐expression and co‐localization in C. albicans cells in vivo. Copyright © 2001 John Wiley & Sons, Ltd.
Sulphur amino acid synthesis in Schizosaccharomyces pombe represents a specific variant of sulphur metabolism in fungi
Authors: Brzywczy Jerzy , Sieńko Marzena , Kucharska Agnieszka , Paszewski Andrzej
Published: August 2002

Schizosaccharomyces pombe, in contrast to Saccharomyces cerevisiae and Aspergillus nidulans, lacks cystathionine β‐synthase and cystathionine γ‐lyase, two enzymes in the pathway from methionine to cysteine. As a consequence, methionine cannot serve as an efficient sulphur source for the fungus and does not bring about repression of sulphur assimilation, which is under control of the cysteine‐mediated sulphur metabolite repression system. This system operates at the transcriptional level, as was shown for the homocysteine synthase encoding gene. Our results corroborate the growing evidence that cysteine is the major low‐molecular‐weight effector in the regulation of sulphur metabolism in bacteria, fungi and plants. The Sz. pombe homocysteine synthase gene sequence was submitted to GenBank under Accession No. AF012876. Copyright © 2002 John Wiley & Sons, Ltd.
The hexose transporters of Saccharomyces cerevisiae play different roles during enological fermentation
Authors: Luyten Kattie , Riou Christine , Blondin Bruno
Published: August 2002

We investigated the role of hexose transporters in a Saccharomyces cerevisiae strain derived from an industrial wine strain by carrying out a functional analysis of HXT genes 1–7 under enological conditions. A strain in which the sugar carrier genes HXT1–HXT7 were deleted was constructed and the HXT genes were expressed individually or in combination to evaluate their role under wine alcoholic fermentation conditions. No growth or fermentation was observed in winemaking conditions for the hxt1‐7Δ strain. The low‐affinity carriers Hxt1 and Hxt3 were the only carriers giving complete fermentation of sugars when expressed alone, indicating that these carriers play a predominant role in wine fermentation. However, these two carriers have different functions. The Hxt3 transporter is thought to play a major role, as it was the only carrier that gave an almost normal fermentation profile when produced alone. The hxt1 carrier was much less effective during the stationary phase and its role is thought to be restricted to the beginning of fermentation. The high‐affinity carriers Hxt2, Hxt6 and/or Hxt7 were also required for normal fermentation. These high‐affinity transporters have different functions: hxt2 is involved in growth initiation, whereas Hxt6 and/or Hxt7 are required at the end of alcoholic fermentation. This work shows that the successful alcoholic fermentation of wine involves at least four or five hexose carriers, playing different roles at various stages in the fermentation cycle. Copyright © 2002 John Wiley & Sons, Ltd.
Relation of Biliary Bile Acid Output to Hepatic Adenosine Triphosphate Level and Biliary Indocyanine Green Excretion in Humans
Authors: Chijiiwa Kazuo , Mizuta Atsushi , Ueda Junji , Takamatsu Yuji , Nakamura Kenji , Watanabe Masato , Kuroki Syoji , Tanaka Masao
Published: August 2002

We have previously demonstrated that there are two subgroups of patients with different types of biliary bile acid output after relief of obstructive jaundice by percutaneous transhepatic biliary drainage (PTBD). The reason for two groups is not clear but is possibly the difference in hepatic reserve function. The aim of this study was to examine the relation of biliary bile acid output to the hepatic ATP level and biliary excretion rate of indocyanine green (ICG) in humans. Patients whose bile could be collected through a PTBD tube participated in this study. The mean serum total bilirubin concentration was 12.7 mg/dl at the time of PTBD,
decreasing to 1.1 mg/dl before surgery. These patients underwent curative resection for cancer of the bile duct, duodenal papilla, or pancreatic head after the relief of hyperbilirubinemia. Bile was collected at 1‐hour intervals for 5 hours after intravenous administration of ICG (0.5 mg/kg) within a few days before surgery, and a small liver tissue sample was obtained immediately after laparotomy without using ischemic procedures. The concentrations of total bile acid and ICG in bile, the bile flow rate, and the bile acid output and ICG excretion rate in bile over 5 hours were determined. ATP concentrations in liver tissue were determined by high performance liquid chromatography. Results of hepatic ATP levels were correlated with the bile acid output and ICG excretion rate into bile. Both the biliary bile acid output (micromoles per 5 hours) and ICG excretion rate (percent of injected dose of ICG) over 5 hours were significantly correlated with the hepatic ATP level (p = 0.0190 and p = 0.0084, respectively). Neither the bile flow rate nor the serum liver function tests were related to the hepatic ATP level. Significant correlation was found between the bile acid output and the ICG excretion rate (p = 0.0127). Biliary bile acid output reflects the hepatic ATP level. Determination of the biliary bile acid output and ICG excretion may provide useful parameters for evaluating the hepatic energy status, which is essential for organ viability.
Early Colorectal Cancer with Special Reference to the Superficial Nonpolypoid Type from a Histopathologic Point of View
Authors: Ajioka Yoichi , Watanabe Hidenobu , Kazama Shinsuke , Hashidate Hideki , Yokoyama Junji , Yamada Satoshi , Takaku Hideya , Nishikura Ken
Published: August 2002

The incidence and histopathologic characteristics of nonpolypoid (superficial type) early colorectal carcinomas were studied and compared with those of the polypoid type. The superficial type was subclassified as elevated (type IIa), type IIa with central depression (type IIa+IIc), plain (type IIb), depressed (type IIc), and IIc with marginal elevation (type IIc+IIa). The superficial type comprised 22% and 27% of intramucosal and submucosal carcinomas, respectively. Pure type IIb was not found, and there were only three pure type IIc lesions. Type IIa+IIc and IIc+IIa (and IIc) showed a significantly higher rate of submucosal invasion among the small tumors (59% and 71% less than 20 mm, respectively) compared to the polypoid type; type IIa showed no significant difference. The incidence of lymph node metastasis among submucosal carcinomas showed no significant difference between the superficial type and the polypoid type. About 64% and 52% of type IIa and IIa+IIc tumors accompanied residual adenoma, suggesting that they originated from small, flat adenomas through the adenoma—carcinoma sequence, whereas type IIc+IIa (and IIc) did not have an adenomatous component, implying that they arose de novo or originated through an adenoma—carcinoma sequence at a smaller size than the type IIa and IIa+IIc lesions. Superficial‐type early colorectal carcinomas are not rare, and they are not uniform in nature. Rapid growth and invasion to the submucosa is characteristic of superficial‐type lesions with a central depression, and only superficial depressed (type IIc+IIa, IIc) lesions can arise de novo. Although they grow rapidly to invade the submucosa, it cannot be said that they show more aggressive behavior than the polypoid type.
Nuclear Medicine Applications for Neuroendocrine Tumors
Authors: Chatal J.F. , Le Bodic M.F. , Kraeber‐Bodéré F. , Rousseau C. , Resche I.
Published: August 2002

Sensitive, specific radiopharmaceuticals are available for scintigraphic diagnosis and internal radiotherapy of neuroendocrine tumors. 123I‐MIBG (metaiodobenzylguanidine) scintigraphy is the examination of choice for visualizing tumor sites of pheochromocytoma. In the event of malignant pheochromocytoma or carcinoid tumor, this examination allows assessment of the presence or absence of tumor uptake and can guide radiotherapy with 131I‐MIBG. The peptides secreted by neuroendocrine tumors can be radiolabeled for targeting of their specific receptors. Scintigraphy using a 111In‐labeled somatostatin analog (octreotide) is the examination of choice for diagnosis of the spread of gastroenteropancreatic and carcinoid tumors, as it is more sensitive than morphologic imaging techniques. It can also guide radiotherapy performed with the same pharmaceutical vector. These same two agents (MIBG and octreotide) can be used therapeutically by replacing 123I with 131I and 111In by 90Y. A transient palliative effect is obtained for a variable number of tumors (most often large ones) that take up the radiopharmaceutic agent well. There is general consensus that, for relatively radioresistant solid tumors, this type of radiotherapy is efficient only in the event of small tumor targets (a few millimeters in diameter) whose uptake is maximal, allowing more homogeneous distribution than that achieved with large tumors. Thus for optimal control of the disease it is recommended first to use scintigraphic imaging to confirm that the tumor takes up the radiopharmaceutical agent in question (123I‐MIBG or 111In‐octreotide) and then reduce the tumor burden surgically before injecting high therapeutic activity (possibly with reinjection of peripheral stem cells). This treatment can be repeated three times every 3 months before evaluating the response. In these conditions, internal radiotherapy can be beneficial or even determinant for controlling disease progression.
Creation, Evaluation, and Continuing Assurance of Excellence of the Certified Surgical Specialist
Authors: Nyhus Lloyd M. , Idezuki Yasuo , Sheldon Donald , McCusker Ivan , Griffen Ward O.
Published: August 2002

A position paper on the subject of certified surgical specialists was published in 1966 under the direction of Professor Charles Wells of Liverpool, England. President John Terblanche of the International Federation of Surgical Colleges brought together leaders in surgical education from four nations (Australia, Japan, South Africa, United States) to update current “state‐of‐the art” views. Presentations were made at the 38th Congress of the International Society of Surgery, August 18, 1999 in Vienna, Austria. After careful review of the four presentations, it was clear that surgeons all over the world have made great improvements in the many facets of surgical education. Yet the advances remain spotty, with gaps noted when viewed from an international perspective.
Outcome of Surgical Intervention for Rectoneovaginal Fistulas in Mayer‐Rokitansky‐Kuester‐Hauser Syndrome
Authors: Schult Marc , Wolters Heiner H. , Lellé Rainer J. , Winde Günther , Senninger Norbert
Published: August 2002

Creation of a neovagina to treat vaginal atresia or aplasia in Mayer‐Rokitansky‐Kuester‐Hauser syndrome must always be followed by long‐term application of dilators to avoid shrinkage. However, rectoneovaginal fistulas are caused by chronic alteration and consecutive necrosis of the posterior neovaginal wall. We evaluated retrospectively the postoperative outcome of rectal wall and neovaginal reconstruction using a standardized surgical technique in an exclusive collection of women. Eight women with a mean age of 28 years (range 22–31 years) were treated for rectoneovaginal fistulas in our clinic. Preoperatively, proctoscopy, sphincter manometry, endoluminal rectal ultrasonography, and colonoscopy were performed; and regular postoperative follow‐up by digital examination and rectoscopy were obligate. The standard surgical procedure via a perineal approach included fistulectomy and closure of the mucosa and rectal wall followed by a levatorplasty. All but one woman had a temporary colostomy. After 2 weeks the patients were allowed to wear vaginal dilators of a smaller size. Within the mean follow‐up period of 20 months, reintervention was necessary twice because of late fistula relapse detected by proctoscopy, barium enema, and subjective symptoms. Morbidity was 25% (n= 2) due to secondary superficial wound healing or urinary tract infection. The average time of the hospital stay was 13 days (10–14 days). One patient complained of vaginal shrinkage and underwent local estrogen therapy with a good functional result 3 months later. Proper fistulectomy and surgical reconstruction with interpositioning of well perfused muscle layers achieved good functional outcome with an acceptable number of minor morbidities. Local estrogen treatment is helpful for avoiding scarification and decreasing the neovaginal size.
Value of Somatostatin Receptor Scintigraphy for Preoperative Localization of Carcinoids
Authors: Kisker O. , Weinel R.J. , Geks J. , Zacara F. , Joseph K. , Rothmund M.
Published: August 2002

Most carcinoid primary tumors are small and do not cause symptoms until complications (e.g. intestinal obstruction) or symptoms and signs of the carcinoid syndrome occur. Therefore in most cases an assessment of the primary tumor and its metastases must be performed. To determine the value of somatostatin receptor scintigraphy (SRS) for localizing carcinoid tumors, we compared the results of SRS with those obtained with computed tomography (CT) and ultrasonography (US) in 22 patients who had not undergone surgery for removal of the primary tumor. We could not find an advantage of SRS over CT and US for detecting the primary lesions. Tumors > 2 cm in diameter were regularly detected using all methods. SRS was not superior to CT or US for the detection of liver metastases. SRS showed the liver metastases in 16 of 18 patients, whereas CT and US detected liver metastases in all patients. For localization of extrahepatic abdominal and extraabdominal metastases (lymph nodes, bone), whole‐body SRS showed an advantage over CT and US. We conclude that SRS is not superior to CT or US for localization of primary carcinoid tumors or liver metastases, although it did prove successful for visualizing extrahepatic and extraabdominal tumor spread. Additionally, SRS is useful for identifying receptor‐positive metastases that may be treated by somatostatin analogs. Thus SRS should be performed in patients with a known carcinoid tumor, except those with an appendiceal carcinoid measuring < 1 cm in diameter.
Characteristic Histologic Features of Human Hepatocellular Carcinoma with Mutant p53 Protein
Authors: Okuda Toyokazu , Hirohashi Kazuhiro , Kinoshita Hiroaki , Wakasa Kenichi , Sakurai Masami
Published: August 2002

To characterize hepatocellular carcinoma (HCC) cells with mutant (m) p53 protein histologically, we examined 68 main nodules and 20 accessory lesions of 72 patients with HCC who underwent hepatic resection between October 1990 and September 1993. Some sections were fixed in periodate‐lysine‐paraformaldehyde, embedded in OCT compound, and stained with the mouse monoclonal antibody PAb1801 to m‐p53 protein by the immunoperoxidase technique with avidin‐biotin complexes. Other sections were fixed in 20% buffered formalin, embedded in paraffin, and stained with the mouse monoclonal antibody DO‐1 to m‐p53 protein in the same way. Lesions in which cells had nuclei stained for m‐p53 protein were defined as being positive for the protein; 25 of the 68 main nodules and 14 of the 20 accessory lesions were positive. Large main nodules were more likely to be positive than small ones. Microscopic examination showed that a larger proportion of poorly differentiated main nodules than well differentiated nodules were positive. Larger proportions of main nodules with extracapsular invasion, septa, portal thrombi, or intrahepatic metastases were positive than main nodules without these features. Accessory lesions that seemed to be metastatic were almost all positive, but few accessory lesions that seemed to be of multicentric occurrence were positive. Our results suggest that lesions with m‐p53 protein had a high grade of malignancy and metastasized readily.
Somatostatin Receptor Localization of Pancreatic Endocrine Tumors
Authors: Corleto V.D. , Scopinaro F. , Angeletti S. , Materia A. , Basso N. , Polettini E. , Annibale B. , Schillaci O. , D’Ambra G. , Marignani M. , Gualdi G. , Bordi C. , Passaro E.J. , Delle Fave G.
Published: August 2002

Gastroenteropancreatic endocrine tumors are difficult to localize. At the same time the tumor is localized, though, there is an opportunity for cure or to remove tumor tissue. In this study we have prospectively examined the ability of 111In‐octreotide scintigraphy, magnetic resonance imaging (MRI), and computed tomography (CT) to localize tumor lesions in 24 patients with a biochemical or histologic diagnosis of neuroendocrine tumor. In eight patients a surgical assessment of the imaging results was prospectively performed. Planar and abdominal single‐photon emission tomography (SPET) images acquired 4 and 24 hours after 180 to 220 MBq of 111In‐octreotide injection were evaluated and compared with conventional imaging techniques. SPET scintigraphy visualized more presumed tumor lesions (n= 39) than conventional imaging studies (MRI,n= 25; CT,n= 13); 23 of 24 patients had positive octreotide scintigraphy, 17 of 24 had positive MRI‐scans, and 12 of 24 patients had positive CT scans. It was concluded that 111In‐octreotide scintigraphy combined with conventional imaging improves the preoperative localization of presumably tumorous lesions in patients with gastroenterohepatic endocrine tumors.
Comparison of Routine and Selective Endoscopic Retrograde Cholangiography before Laparoscopic Cholecystectomy
Authors: Tanaka Masao , Sada Masayuki , Eguchi Toru , Konomi Hiroyuki , Naritomi Gen , Takeda Torahiko , Ogawa Yoshiaki , Chijiiwa Kazuo , Deenitchin Georgi P.
Published: August 2002

To evaluate the role of endoscopic retrograde cholangiography (ERC) before laparoscopic cholecystectomy, we compared the frequency of concomitant common bile duct stones, their clinical outcome, and the frequency of bile duct injury between a group of 128 patients with routine preoperative ERC (group A) and 1010 patients with selective ERC (group B). Overall, 48 patients (4.2%) had duct stones, but the predictive signs were absent in six of them (12.5%). The stones were demonstrated by ERC and removed by sphincterotomy in all 11 patients in group A. Of 37 patients in group B, 22 were diagnosed by selective ERC and underwent endoscopic removal. Of four patients whose stones were found by operative cholangiography, one had immediate open surgery, another passed a stone spontaneously, and the other two underwent postoperative sphincterotomy, which failed in one. The stones were not recognized until pain recurred in the remaining 11 patients. Sphincterotomy was successful in nine patients but failed in the other two. Thus postoperative sphincterotomy failed in 3 of 13 patients (23%), necessitating open surgery. Forty‐two patients overall (3.7%) had aberrant biliary tract anatomy, which did not lead to bile duct injury in any of the patients. Morbidity of routine ERC (3.1%) was lower than that of selective ERC (7.4%) (p< 0.05). It should be noted that a certain proportion of duct stones may be missed by selective ERC, necessitating laparotomy when sphincterotomy fails. The routine use of preoperative ERC may be justified at institutions where the expertise is available, at least until laparoscopic lithotomy becomes easy.
Side Localization of Parathyroid Adenomas by Simplified Intraoperative Venous Sampling for Parathyroid Hormone
Authors: Bergenfelz Anders , Algotsson Lars , Roth Bengt , Isaksson Anders , Tibblin Sten
Published: August 2002

Side localization of parathyroid adenomas was performed by venous sampling for intact parathyroid hormone (PTH) in 20 consecutive patients with primary hyperparathyroidism (pHPT) after induction of anesthesia. The results were thus available during surgery. Nineteen of the patients had solitary parathyroid adenoma, and one had hyperplasia. There was no complication to the procedure. A lateralizing PTH gradient for a parathyroid adenoma was obtained in 13 patients. At surgery 12 of them (92%) were proved correct; that is, the adenoma was localized on the same side. Thus the technique correctly lateralized the adenoma in 12 of 19 patients (63%). We therefore conclude that the method of intraoperative venous sampling for intact PTH is safe, and the predictive value of a lateralizing gradient is high. It could therefore be used as an adjunct to surgical skill and noninvasive localization procedures in selected cases, for instance in patients with prior neck surgery and hypercalcemic crisis.
Multiple Organ Failure: Is It Disappearing?
Authors: Levine Jeffrey H. , Durham Rodney M. , Moran John , Baue Arthur
Published: August 2002

The incidence of multiple organ failure (MOF) during the last decade has been reported variously as 2% to 25%, depending on the patient population examined. The mortality rate from this devastating complication ranges from 40% to 80%. Although the incidence has not changed during the last decade, it does not mean that there has been no progress. Tertiary centers are now seeing trauma and nontrauma patients who have more significant underlying disease and injuries. Likewise, a higher percentage of our trauma patients are now referred from outside institutions where there may not be the facilities to administer the complex, rapid resuscitation these patients require. Prevention of MOF remains its best treatment. Rapid, adequate volume resuscitation, adequate nutrition, appropriate antibiotic usage, and aggressive pulmonary management are important for preventing the downward physiologic spiral that leads to MOF and death. Once MOF has occurred, it is not clear that these same measures are as effective in altering outcome.
Difference between Carcinoma of the Lower Esophagus and the Cardia
Authors: Tachimori Yuji , Kato Hoichi , Watanabe Hiroshi , Sasako Mitsuru , Kinoshita Taira , Maruyama Keiichi
Published: August 2002

We analyzed the records of patients with carcinoma of the lower esophagus and cardia. Mediastinal node involvement was found in 43% of the patients with squamous cell carcinoma of the lower esophagus, and the 5‐year survival after mediastinal dissection for patients with mediastinal node involvement was 27%. Mediastinal node involvement was found in 19% of the patients with adenocarcinoma of the cardia involving the esophagus, and no patients with mediastinal node involvement survived more than 2 years. When the patients had mediastinal node involvement, survival curves were significantly different. There were large differences between these tumors in terms of the extent of lymph node involvement and the survival of patients with mediastinal lymph node involvement. It is incorrect to consider the behavior of these tumors identical and to treat the conditions similarly.
Role and Operative Risk of Bilateral Adrenalectomy in Hypercortisolism
Authors: Chapuis Yves , Pitre Jol , Conti Filomena , Abboud Bassam , Pras‐Jude Nicole , Luton Jean‐Pierre
Published: August 2002

Transsphenoidal pituitary surgery has radically modified the management of pituitary‐dependent hypercortisolism (Cushing's disease). Bilateral adrenalectomy may, however, represent the ultimate treatment in some cases of hypercortisolism. In the present study we report our experience of bilateral adrenalectomy in 82 patients operated on during the last 15 years. The causes of hypercortisolism were Cushing's disease (n= 78), ectopic ACTH syndrome (n= 3), and primary adrenocortical nodular dysplasia (Carney‐Meador syndrome) (n= 1). Before operation 37% of the patients had severe symptoms of hypercortisolism. A bilateral posterior approach was undertaken in 58 patients, whereas 18 patients had an anterior transabdominal approach and 6 patients a laparoscopic approach. There were two operative deaths (2.4%). Postoperative complications occurred mostly in cases of advanced disease and were observed in 14 patients (17%), among whom 4 had severe complications. At long‐term follow‐up, one recurrence of hypercortisolism and 12 Nelson syndromes (15%) were observed. In conclusion, bilateral adrenalectomy carries an acceptable operative risk, and we recommend bilateral adrenalectomy rather than long‐term suppressive therapy in patients requiring prompt and definitive control of their hypercortisolism or after pituitary surgery failure.