bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of the equivalence approach in reproductive health clinical trials
Authors: Piaggio Gilda , Pinol Alain P. Y.
Published: August 2002

An equivalence trial is appropriate when it is desired to demonstrate equivalence between two treatments, regimens or interventions (methods) or non‐inferiority of a new one compared to a standard one. The conduct of an equivalence trial requires different techniques during design and analysis compared to a superiority trial. The existing formulae for sample size calculation to demonstrate equivalence between two methods using the confidence interval approach are reviewed. The establishment of the margin of equivalence and the choice of the type of test are discussed. Plots of sample sizes required to demonstrate equivalence in the case of binary outcomes are presented for values of proportions and margins of equivalence common in the reproductive health field. Examples are given of method comparisons in the reproductive health field in which the relevant question is to demonstrate non‐inferiority. The approach to equivalence is described in the trials included in three published systematic reviews in which these comparisons were conducted, addressing the statement of hypotheses, sample size calculation and the interpretation of results. The use of the conventional superiority approach to design equivalence trials has led to underpowered trials to show equivalence within clinical relevant margins. The analysis and interpretation of results from such trials has resulted in conclusions of equivalence based on lack of significance. We draw attention to the lack of awareness of the appropriate techniques for equivalence trials among researchers in the field of reproductive health. Finally, the issue of interim analyses and stopping rules in equivalence trials is addressed. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of mixed categorical data in 2×K contingency tables
Authors: Gautam Shiva
Published: August 2002

2×K contingency tables having both ordinal and nominal categories are often encountered in various types of studies. Such data are referred to as ‘mixed’ categorical data in this article. To apply a method for ordered categorical data one has to discard the nominal categories, and to apply a method for nominal categories one has to discard the ordering information inherent in the ordered categories. Therefore, investigators often either discard observations in nominal categories or discard the ordering of the categories before analysing such data. Some information will be lost in both approaches. A method for analysing data in 2×K ‘mixed’ tables is proposed in this paper which can be considered as an extension of well known methods for nominal and ordered categories. The proposed method utilizes observations in the nominal categories as well as the ordering information. If all the categories were ordered then the proposed method reduces to the trend test, and if all the categories were nominal then the proposed method reduced to Pearson's chi‐square test. Copyright © 2002 John Wiley & Sons, Ltd.
Impact of missing data due to drop‐outs on estimators for rates of change in longitudinal studies: a simulation study
Authors: Touloumi G. , Babiker A. G. , Pocock S. J. , Darbyshire J. H.
Published: August 2002

Many cohort studies and clinical trials are designed to compare rates of change over time in one or more disease markers in several groups. One major problem in such longitudinal studies is missing data due to patient drop‐out. The bias and efficiency of six different methods to estimate rates of changes in longitudinal studies with incomplete observations were compared: generalized estimating equation estimates (GEE) proposed by Liang and Zeger (1986); unweighted average of ordinary least squares (OLSE) of individual rates of change (UWLS); weighted average of OLSE (WLS); conditional linear model estimates (CLE), a covariate type estimates proposed by Wu and Bailey (1989); random effect (RE), and joint multivariate RE (JMRE) estimates. The latter method combines a linear RE model for the underlying pattern of the marker with a log‐normal survival model for informative drop‐out process. The performance of these methods in the presence of missing data completely at random (MCAR), at random (MAR) and non‐ignorable (NIM) were compared in simulation studies. Data for the disease marker were generated under the linear random effects model with parameter values derived from realistic examples in HIV infection. Rates of drop‐out, assumed to increase over time, were allowed to be independent of marker values or to depend either only on previous marker values or on both previous and current marker values. Under MACR all six methods yielded unbiased estimates of both group mean rates and between‐group difference. However, the cross‐sectional view of the data in the GEE method resulted in seriously biased estimates under MAR and NIM drop‐out process. The bias in the estimates ranged from 30 per cent to 50 per cent. The degree of bias in the GEE estimates increases with the severity of non‐randomness and with the proportion of MAR data. Under MCAR and MAR all the other five methods performed relatively well. RE and JMRE estimates were more efficient(that is, had smaller variance) than UWLS, WLS and CL estimates. Under NIM, WLS and particularly RE estimates tended to underestimate the average rate of marker change (bias≈10 per cent). Under NIM, UWLS, CL and JMRE performed better in terms of bias (3–5 per cent) with the JMRE giving the most efficient estimates. Given that markers are key variables related to disease progression, missing marker data are likely to be at least MAR. Thus, the GEE method may not be appropriate for analysing such longitudinal marker data. The potential biases due to incomplete data require greater recognition in reports of longitudinal studies. Sensitivity analyses to assess the effect of drop‐outs on inferences about the target parameters are important. Copyright © 2001 John Wiley & Sons, Ltd.
Quantifying heterogeneity in a meta‐analysis
Authors: Higgins Julian P. T. , Thompson Simon G.
Published: August 2002

The extent of heterogeneity in a meta‐analysis partly determines the difficulty in drawing overall conclusions. This extent may be measured by estimating a between‐study variance, but interpretation is then specific to a particular treatment effect metric. A test for the existence of heterogeneity exists, but depends on the number of studies in the meta‐analysis. We develop measures of the impact of heterogeneity on a meta‐analysis, from mathematical criteria, that are independent of the number of studies and the treatment effect metric. We derive and propose three suitable statistics: H is the square root of the χ2 heterogeneity statistic divided by its degrees of freedom; R is the ratio of the standard error of the underlying mean from a random effects meta‐analysis to the standard error of a fixed effect meta‐analytic estimate, and I2 is a transformation of H that describes the proportion of total variation in study estimates that is due to heterogeneity. We discuss interpretation, interval estimates and other properties of these measures and examine them in five example data sets showing different amounts of heterogeneity. We conclude that H and I2, which can usually be calculated for published meta‐analyses, are particularly useful summaries of the impact of heterogeneity. One or both should be presented in published meta‐analyses in preference to the test for heterogeneity. Copyright © 2002 John Wiley & Sons, Ltd.
A method for the analysis of repeated binary outcomes in randomized clinical trials with non‐compliance
Authors: Sato Tosiya
Published: August 2002

When analysing repeated binary data from randomized trials, the model‐based approaches, such as generalized estimating equations, are frequently used. Such methods ignore compliance information and give the model‐based intention‐to‐treat estimate of treatment effect. In this paper, the design‐based (randomization‐based) semi‐parametric estimation procedure is given in the estimation of causal risk difference. The resulting risk difference estimator is interpreted as an extension of the instrumental variables estimator for a binary outcome which has the causal interpretation. Extension of the proposed method to stratified analysis is given for data from stratified randomization or meta‐analysis. It yields a Mantel–Haenszel type risk difference estimator. As a special case of stratified analysis, the pattern mixture model which stratifies the data by pattern of missing data is performed. Application of the proposed method to a trial in which endpoints were the occurrences of fever over three courses is provided. The same ideas are applied to the causal risk ratio estimation. Copyright © 2001 John Wiley & Sons, Ltd.
Incremental net benefit in randomized clinical trials
Authors: Willan Andrew R. , Lin D. Y.
Published: August 2002

There are three approaches to health economic evaluation for comparing two therapies. These are (i) cost minimization, in which one assumes or observes no difference in effectiveness, (ii) incremental cost‐effectiveness, and (iii) incremental net benefit. The latter can be expressed either in units of effectiveness or costs. When analysing data from a clinical trial, expressing incremental net benefit in units of cost allows the investigator to examine all three approaches in a single graph, complete with the corresponding statistical inferences. Furthermore, if costs and effectiveness are not censored, this can be achieved using common two‐sample statistical procedures. The above will be illustrated using two examples, one with censoring and one without. Copyright © 2001 John Wiley & Sons, Ltd.
Entrepreneurship in the large corporation: a longitudinal study of how established firms create breakthrough inventions
Authors: Ahuja Gautam , Morris Lampert Curba
Published: August 2002

We present a model that explains how established firms create breakthrough inventions. We identify three organizational pathologies that inhibit breakthrough inventions: the familiarity trap – favoring the familiar; the maturity trap – favoring the mature; and the propinquity trap – favoring search for solutions near to existing solutions. We argue that by experimenting with novel (i.e., technologies in which the firm lacks prior experience), emerging (technologies that are recent or newly developed in the industry), and pioneering (technologies that do not build on any existing technologies) technologies firms can overcome these traps and create breakthrough inventions. Empirical evidence from the chemicals industry supports our model. Copyright © 2001 John Wiley & Sons, Ltd.
Social capital, knowledge acquisition, and knowledge exploitation in young technology‐based firms
Authors: Yli‐Renko Helena , Autio Erkko , Sapienza Harry J.
Published: August 2002

Employing a sample of 180 entrepreneurial high‐technology ventures based in the United Kingdom, we examine the effects of social capital in key customer relationships on knowledge acquisition and knowledge exploitation. Building on the relational view and on social capital and knowledge‐based theories, we propose that social capital facilitates external knowledge acquisition in key customer relationships and that such knowledge mediates the relationship between social capital and knowledge exploitation for competitive advantage. Our results indicate that the social interaction and network ties dimensions of social capital are indeed associated with greater knowledge acquisition, but that the relationship quality dimension is negatively associated with knowledge acquisition. Knowledge acquisition is, in turn, positively associated with knowledge exploitation for competitive advantage through new product development, technological distinctiveness, and sales cost efficiency. Further, our results provide evidence that knowledge acquisition plays a mediating role between social capital and knowledge exploitation. Copyright © 2001 John Wiley & Sons, Ltd.
Variations in ownership behavior and propensity to diversify: a study of the Indian corporate context
Authors: Ramaswamy Kannan , Li Mingfang , Veliyath Rajaram
Published: August 2002

The relationship between ownership and diversification has been the focus of renewed debate between financial economists and strategic management scholars. While financial economists hold that manager‐controlled firms tend to reflect higher levels of diversification, strategy researchers argue that ownership and diversification are not systematically related. In throwing light on this debate, this study uses a fine‐grained definition of ownership groups to explore how the different objectives and monitoring predispositions of distinct ownership groups might influence diversification strategy. The empirical examination is set in India to offer a striking contrast from the predominantly U.S.‐based studies that have shaped the ongoing debate. Findings show that diverse ownership groups adopt different postures in monitoring and/or influencing organizational diversification. While some ownership groups are closely associated with focused strategies, and some encourage diversification, others are quite indifferent. These results suggest that the context‐specific variation among ownership groups is germane to our understanding of diversification strategy. Copyright © 2002 John Wiley & Sons, Ltd.
Option value and entry timing
Authors: Miller Kent D. , Folta Timothy B.
Published: August 2002

When facing uncertainty, firms entering new markets can make initial foothold investments rather than undertake large sunk investments. Such investments are real call option purchases. They offer management flexibility, but also raise questions about whether and when to increase commitments to new markets. We present an entry timing decision criterion and discuss its application to a variety of market entry situations. Optimal timing for exercising real options depends on current dividends, possibilities for preemption, and whether the option is simple or compound, proprietary or shared. Our analysis reveals critical assumptions and new theoretical insights regarding market entry timing. Copyright © 2002 John Wiley & Sons, Ltd.
Field studies using functional size measurement in building estimation models for software maintenance
Authors: Abran Alain , Silva Ilionar , Primera Laura
Published: August 2002

Even though a significant number of estimation models have been proposed for development projects, few have been proposed for software maintenance. This paper reports on two field studies carried out on the use of functional size measures in building estimation models for sets of maintenance projects implementing small functional enhancements in existing software. The first field‐study reports on models built with 15 projects making functional enhancements to an internet‐based software program for linguistic applications. The second field study analyses 19 maintenance projects on a single real‐time embedded software program in the defense industry. Both field studies collected functional size measures using version 2.0 of the COSMIC‐FFP functional size measurement method. Also both field studies classified projects into two classes of project difficulty in order to aid identifying subsets of projects with greater homogeneity in the relationship of project effort to functional size. This paper is the first published paper reporting on the use this second generation of functional size‐measurement methods in a maintenance‐estimation context. Copyright © 2002 John Wiley & Sons, Ltd.
On misdirected systemsa
Authors: Ackoff Russell L. , Pourdehnad John
Published: August 2002

Many, if not most, social systems are trying to do things right, but are not doing the right things. Examples are drawn from transportation, health care, law and order, and education. In addition, it is argued that most corporations do not practice what they preach, and that such remedies as downsizing are dysfunctional and harmful to society. Copyright © 2001 John Wiley & Sons, Ltd.
Connection matters: exploring the implications of social capital and social networks for social policy
Authors: White Leroy
Published: August 2002

The concept of social capital is a useful metaphor which suggests that a society with a rich web of relationships and widespread participation in community organizations will flourish, at many levels including the economic. Furthermore individuals who hold large accumulations of social capital will be at an advantage over others with less. A number of people, particularly ‘third way thinkers,’ have taken up the theme in the UK context. The view is that it can be an indicator of social change or its accumulation will lead to social change in some form. In this paper an overview of some of the developments of social capital will be given. The issue about measurement will be addressed, particularly social networks as a proxy to social capital. Some recent application to current social and health policy programmes will be explored. Finally some questions about whether social networks are an indicator of social capital will also be explored. Copyright © 2002 John Wiley & Sons, Ltd.
Prenatal cocaine exposure increases mesoprefrontal dopamine neuron responsivity to mild stress
Authors: Elsworth John D. , Morrow Bret A. , Roth Robert H.
Published: August 2002

Children whose mothers used cocaine during pregnancy appear to have an increased incidence of certain neurobehavioral deficits. Rodent models of prenatal cocaine exposure have mimicked these deficits in the offspring, yet the biochemical basis of the behavioral abnormalities is unknown. We have been able to reproduce short‐term memory deficits in our rat intravenous model of prenatal cocaine exposure, and as short‐term memory is dependent on the function of dopamine neurons innervating the medial prefrontal cortex, we hypothesized that prenatal cocaine induces a dysfunction in the regulation of this pathway. Here we report that mild footshock stress, which preferentially activates the mesoprefrontal dopamine system, leads to an enhanced increase in dopamine turnover in the ventromedial prefrontal cortex of adolescent (postnatal day 35–37) rats exposed to cocaine in utero, suggesting that the dopamine neurons innervating this region are hyperresponsive in these rats. Thus, this biochemical alteration may be central to some of the cognitive deficits exhibited by offspring that were exposed to cocaine during fetal development. Synapse 42:80–83, 2001. © 2001 Wiley‐Liss, Inc.
Insufficient folic acid intake in the Netherlands: What about the future?
Authors: De Walle H.E.K. , De Jong‐Van Den Berg L.T.W.
Published: August 2002

Background

In 1993 all women of childbearing age in the Netherlands were advised to take a daily 0.5 mg folic acid pill to reduce the risk for neural tube defects. This study describes both recent and past awareness and use of folic acid supplements in relation to socio‐economic status in the Northern Netherlands. The consequences of a recent report of the Dutch Health Council report will be discussed as well.

Methods

In the most recent cross‐sectional study (November 2000), pregnant women filled out a questionnaire. Out of 473 women, 461 were willing to cooperate. The highest fulfilled level of education was taken as an indicator for socio‐economic status.

Results

Seventy‐seven percent (n = 357) of the respondents had heard about folic acid before being pregnant. Sixty‐three percent (n = 289) knew about the protective effect for NTDs and 33% (n = 151) knew the entire advised period. Sixty‐one percent (n = 265) of the respondents used folic acid in some part of the advised period and 36% (n = 164) used it in the entire advised period. Higher educated women knew more about folic acid and used it significantly more often in the periconceptional period than lower educated women.

Conclusions

Because compliance to proper use of folic acid was poor, food fortification in the Netherlands must be seriously considered. The Dutch Health Council wants to limit the fortification of food products to those products that are especially aimed for women who wish to become pregnant. The fortification of specific products instead of staple foods is a missed chance to reduce NTDs and possibly other birth defects and cardiovascular defects as well. Teratology 66:40–43, 2002. © 2002 Wiley‐Liss, Inc.
Characterization of the aryl hydrocarbon receptor repressor gene and association of its Pro185Ala polymorphism with micropenis
Authors: Fujita Hideki , Kosaki Rika , Yoshihashi Hiroshi , Ogata Tsutomu , Tomita Masaru , Hasegawa Tomonobu , Takahashi Takao , Matsuo Nobutake , Kosaki Kenjiro
Published: August 2002

Background

Genetic background of a fetus contributes to the abnormal development after teratogen exposure. In rodents, in utero exposure to dioxins affects male external genital development. The effects of dioxins are mediated via the aryl hydrocarbon receptor (AHR) and its binding protein, aryl hydrocarbon receptor nuclear translocator (ARNT). In mice, aryl hydrocarbon receptor repressor (AHRR), which binds to ARNT in competition with AHR, plays a critical negative regulatory role in AHR signaling. We attempt to characterize the human AHRR gene and investigate the relationship between AHRR polymorphisms and the incidence of micropenis, a phenotype of undermasculinization.

Methods

We identified and characterized the human homolog of mouse AHRR, taking advantage of the publicly available draft version of the human genome sequence. After detecting an AHRR protein polymorphism by the direct sequencing of pooled human genomic DNA, we evaluated the association between the polymorphism and the presence or absence of micropenis (<−2.5 SD) in patients with micropenis and control subjects.

Results

The deduced sequence for human AHRR (715 residues) and the mouse AHRR protein exhibited 81% sequence homology to each other. The Pro185Ala polymorphism was identified between the PAS‐A region and the highly conserved arginine/cysteine‐rich RCFRCRL/VRC region. Forty‐six percent (27/59) of patients with micropenis and 27% (22/80) of the controls were homozygous for 185Pro; this difference in frequencies was significant (P = 0.03).

Conclusions

Homozygosity for the 185Pro allele of AHRR may increase the susceptibility of a fetus to the undermasculinizing effects of dioxin exposure in utero, presumably through the diminished inhibition of AHR‐mediated signaling. Teratology 65:10–18, 2002. © 2002 Wiley‐Liss, Inc.
Brazil.com
Authors: DeGouvea Raul , Kassicieh Suleiman K.
Published: August 2002

E‐commerce is rapidly becoming an important component of business environments. The use of the Web
internationally has its challenges and its potential. This article examines the Brazilian e‐business
environment that has been undergoing dramatic changes. It analyzes these changes and the business models
required for success in this prominent Latin American market. © 2002 John Wiley & Sons, Inc.
Interaction of SMKT, a killer toxin produced by Pichia farinosa, with the yeast cell membranes
Authors: Suzuki Chise , Ando Yoshiji , Machida Sachiko
Published: August 2002

SMKT (salt‐mediated killer toxin), a killer toxin produced by the halotolerant yeast, Pichia farinosa, kills yeasts of several genera, including Saccharomyces cerevisiae. To elucidate the killing mechanism of SMKT, we examined the interaction of SMKT with membranes using liposomes. Leakage of calcein from calcein‐entrapped liposomes was observed in the presence of SMKT. Destruction of liposomes was observed by dark‐field microscopy. Comparison of intact S. cerevisiae cells with SMKT‐treated cells by dark‐field microscopy indicated that the spherical cell membrane is disrupted by SMKT. Using sodium carbonate extraction, we obtained direct evidence for the first time that SMKT is associated with the membrane of sensitive cells. Our results indicate that SMKT kills sensitive S. cerevisiae by interacting with the yeast cell membrane. Copyright © 2001 John Wiley & Sons, Ltd.
Revisiting the yeast chromosome VI DNA sequence reveals a correction merging YFL007w and YFL006w to a single ORF
Authors: Robben Johan , Hertveldt Kirsten , Volckaert Guido
Published: August 2002

The overall contiguity of the Saccharomyces cerevisiae chromosome VI sequence assembly was assessed by systematic long‐range PCR, PCR product size determination and sequencing. Using S. cerevisiae strain FY1679 total genomic DNA as template, 41 overlapping PCR products were generated, covering the complete 270 kb chromosome VI sequence. Specificity of the PCR products was confirmed by direct end‐sequencing. No fragment size discrepancies with the published sequence were observed, confirming the overall sequence assembly. Gel reads of the PCR‐fragment ends compile to a total of resequenced DNA representing 16% of the entire chromosome VI and reveal three single nucleotide differences. One of these is an extra G in the protein‐coding region of YFL007w. Due to this additional nucleotide, the coding sequences of YFL007w and YFL006w become part of a 6432 bp ORF. The same sequence also resulted from analysis of strain BY4743. Homologous proteins of unknown function found in Candida albicans, Arabidopsis thaliana, Caenorhabditis elegans and man, as well as comparative data from published transcript profiles of YFL006w and YFL007w, give additional evidence for the existence of a single gene at this locus in yeast. Copyright © 2002 John Wiley & Sons, Ltd.
Philosophy of environmental enrichment: Past, present, and future
Authors: Mellen Jill , Sevenich MacPhee Marty
Published: August 2002

The brief tenure of environmental enrichment has been influenced both directly and indirectly by the field of psychology, from the work of B.F. Skinner to that of Hal Markowitz. Research on enrichment supports the supposition that an enriched environment does indeed contribute to a captive animal’s well‐being. Critical elements of effective environmental enrichment are 1) assessing the animal’s natural history, individual history, and exhibit constraints and 2) providing species‐appropriate opportunities, i.e., the animal should have some choices within its environment. This paper presents a historic perspective of environmental enrichment, proposes a broader, more holistic approach to the enrichment of animals in captive environments, and describes a framework or process that will ensure a consistent and self‐sustaining enrichment program. Zoo Biol 20:211–226, 2001. © 2001 Wiley‐Liss, Inc.
Embeddable anticonformal automorphisms of Riemann surfaces
Authors: Costa Antonio F.
Published: August 2002

Let S be a Riemann surface and f be an automorphism of finite order of S. We call f embeddable if there is a conformal embedding

e : S \to \bf {E}^3

such that

e \circ f \circ e^{-1}

is the restriction to e(S) of a rigid motion. In this paper we show that an anticonformal automorphism of finite order is embeddable if and only if it belongs to one of the topological conjugation classes here described. For conformal automorphisms a similar result was known by R.A. RÃ¼edy [R3].
The asymptotic behavior of the set of rays
Authors: Mendonça S. J.
Published: August 2002

We introduce new invariants to study the asymptotic behavior of the set of rays and prove a splitting theorem for the radius of the ideal boundary of an open manifold with

K \ge 0

(Shioya's Conjecture).
An example of an immersed complete genus one minimal surface in $ \Bbb {R}^3 $ with two convex ends
Authors: Nelli B.
Published: August 2002

We prove the existence of a compact genus one immersed minimal surface M, whose boundary is the union of two immersed locally convex curves lying in parallel planes. M is a part of a complete minimal surface with two finite total curvature ends.
Platonic surface
Authors: Brooks R.
Published: August 2002

If SO is a Riemann surface with a complete metric of finite area and constant curvature -1, let SC denote the conformal compactification of SO. We show that, under the assumption that the cusps of SO are large, there is a close relationship between the hyperbolic metrics on SO and SC. We use this relationship to show that

\liminf_{k \to \infty} \lambda_1(P_k) \ge 5/36

, where the Platonic surface Pk is the conformal compactification of the modular surface Sk.
Compactification of moduli space of harmonic mappings
Authors: Chen J. , Tian Gang
Published: August 2002

We introduce the notion of harmonic nodal maps from the stratified Riemann surfaces into any compact Riemannian manifolds and prove that the space of the energy minimizing nodal maps is sequentially compact. We also give an existence result for the energy minimizing nodal maps. As an application, we obtain a general existence theorem for minimal surfaces with arbitrary genus in any compact Riemannian manifolds.
The singly periodic genus-one helicoid
Authors: Hoffman D. , Karcher H. , Wei F.
Published: August 2002

We prove the existence of a complete, embedded, singly periodic minimal surface, whose quotient by vertical translations has genus one and two ends. The existence of this surface was announced in our paper in Bulletin of the AMS, 29(1):77-84, 1993. Its ends in the quotient are asymptotic to one full turn of the helicoid, and, like the helicoid, it contains a vertical line. Modulo vertical translations, it has two parallel horizontal lines crossing the vertical axis. The nontrivial symmetries of the surface, modulo vertical translations, consist of:

180^\circ

-rotation about the vertical line;

180^\circ

rotation about the horizontal lines (the same symmetry); and their composition.
Boundary slopes of knots
Authors: Culler M. , Shalen P. B.
Published: August 2002

The results in this paper show that simple connectivity of a 3-manifold is reflected in the behavior of essential surfaces in exteriors of knots in the manifold. A corollary of the main theorem is that any non-trivial knot, with irreducible complement, in a homotopy 3-sphere must have two boundary slopes that differ by at least 2. This statement is false for knots in a homology 3-sphere. The main theorem itself applies more generally to knots in closed orientable 3-manifolds with cyclic fundamental group.
Skeins, SU(N) three-manifold invariants and TQFT
Authors: Lickorish W.B R.
Published: August 2002

The skein theory associated to the HOMFLY polynomial invariant of oriented knots and links in the three-sphere is explored in order to provide the background results necessary for the creation of a Topological Quantum Field Theory. A simple local duality result in the skein theory is proved. It allows vector space dimensions in the theory to be correlated with the structure constants in a skein algebra associated to the solid torus.
Additivity of tunnel number for small knots
Authors: Schultens J.
Published: August 2002

We show that for small knots

K_1, K_2, t(K_1) + t(K_2) - 1 \leq t(K_1\#K_2) \leq t(K_1)+t(K_2)+1

, and that for small knots

K_1, \dots, K_n, t(K_1 \# \dots \# K_n) \geq n

.
Universal octonary diagonal forms over some real quadratic fields
Authors: Kim B. M.
Published: August 2002

In this paper, we will prove there are infinitely many integers n such that

n^2 - 1

is square-free and

\Bbb Q(\sqrt {n^2-1})

admits universal octonary diagonal quadratic forms.
Which joint position puts the axillary nerve at lowest risk when performing arthroscopic capsular release in patients with adhesive capsulitis of the shoulder?
Authors: Jerosch J. , Filler T. , Peuker E.
Published: August 2002

The success of arthroscopic capsular release of the glenohumeral joint depends on complete incision of the inferior capsule. This study determined the distance between capsule and the axillary nerve in different joint positions. In 14 human shoulder specimens the anterior joint capsule and axillary nerve were dissected, and the anterior joint capsule was incised between the 1 and 5 o'clock positions. The shortest distance between the insertion of the inferior capsule and the axillary nerve was measured at the glenoid and humeral insertions in abduction, adduction, internal, and external rotation. The axillary nerve is surrounded from soft connective tissue and is closer to the humeral than to the glenoidal attachment of the joint capsule. During abduction and external rotation the nerve stays in its position while the glenohumeral capsule tightens, which increases the distance between the two structures. This results in the following distances: to the glenoidal/humeral capsule insertion: in adduction and neutral rotation, 21.2±4.2/14.2±2.6 mm; in abduction and neutral rotation, 24.0±4.9/15.0±5.0 mm; in abduction and internal rotation, 21.1±6.6/14.6±3.7 mm; and in abduction and external rotation, 24.9±3.8/16.4±4.4 mm. Thus, when performing arthroscopic capsular release the incision of the glenohumeral joint capsule should be undertaken at the glenoidal insertion in the abducted and externally rotated shoulder.
Experimental and clinical assessment of the accuracy of knee extension measurement techniques
Authors: Jagodzinski M. , Kleemann V. , Angele P. , Schönhaar V. , Iselborn K.W. , Mall G. , Nerlich M.
Published: August 2002

The purpose of this study was to analyze the accuracy of commonly used techniques for the measurement of knee extension and to compare them with a new measurement device. The bars of an external fixator were used to determine reference knee extension angles of 15 human cadavers. These angles were compared with measurements of knee extension on radiographs limited to the knee joint. Extension was determined in various knee positions using a generic goniometer and a novel long arm goniometer. In a clinical study, two independent examiners categorized knee extension performance according to the IKDC. Sixteen knees with deficits in the range of motion were rated using a generic goniometer, a long arm goniometer and the novel extension measurement device. The radiological measurement of knee extension angles that were restricted to the shaft of femur and tibia had a systematic error of –5.2±1.9° compared with the lines created by the centers of rotation. In the experimental setup, the mean absolute deviations were 3.92±1.41° with a generic goniometer and 1.22±0.20° with the extension measurement device. The variance of the measurements was significantly lower (2.64±0.28) than with the generic goniometer (23.72±4.39;P<0.05). Correspondence in the IKDC rating was 63% using a standard goniometer, 50% with the long arm goniometer, and 96% using the novel device. Radiological measurements of knee extension limited to the area of the knee joint deviates systematically from measurements of the total axis of the bones. A precision goniometer that utilizes bony landmarks of the tibia and femur is superior in accuracy compared with standard and long arm goniometer techniques.
Factors Associated with Clinically Significant Anastomotic Leakage after Large Bowel Resection: Multivariate Analysis of 707 Patients
Authors: Alves Arnaud , Panis Yves , Trancart Danielle , Regimbeau Jean‐Marc , Pocard Marc , Valleur Patrice
Published: August 2002

The aim of this study was to determine by univariate and multivariate analyses the factors associated with clinically significant anastomotic leakage (AL) after large bowel resection. From 1990 to 1997 a series of 707 patients underwent colonic or rectal resection (without a stoma). Patients were divided into two groups: those with clinical anastomotic leakage (group 1) and those without it (group 2). AL occurred in 43 of 707 patients (6%).
The overall mortality was 2.2% and was significantly higher in patients with AL than in those without: 5 of 43 (12%) versus 11 of 664
(1.6%), p <0.001. Univariate analysis showed 15
variables associated with the risk of AL: previous abdominal or pelvic irradiation (p = 0.02), American Society of Anesthesiologists (ASA) score > 2 (p = 0.04),
leukocytosis (p = 0.02), renal failure
(p = 0.03), steroid treatment (p =
0.01), duration of operation (p = 0.001),
intraoperative septic conditions (p = 0.006), total colectomy (p = 0.009), transverse colectomy
(p = 0.02), difficulties encountered during anastomosis (p = 0.001), ileorectal anastomosis
(p = 0.02), colocolic anastomosis (p
= 0.01), abdominal drainage (p = 0.05), and blood transfusion intraoperatively (p = 0.006) and postoperatively (p = 0.001). Multivariate analysis showed that only preoperative leukocytosis (p = 0.04),
intraoperative septic conditions (p = 0.001),
difficulties encountered during anastomosis (p =
0.007), colocolic anastomosis (p = 0.004), and postoperative blood transfusion (p = 0.0007) were independent factors associated with AL. The risk of AL increased from a range of 12% to 30% if one risk factor was present, to 38% with two factors, to 50% with three factors. After colorectal resection and intraperitoneal anastomosis, a temporary protective stoma is proposed in selected patients with high risk factors for AL, as observed in our study.
Efficacy and Safety of Preoperative Lobar or Segmental Ablation via Transarterial Administration of Ethiodol and Ethanol Mixture for Treatment of Hepatocellular Carcinoma: Clinical Study
Authors: Cheng Yu‐fan , Kan Zuxing , Chen Chao‐long , Huang Tung‐liang , Chen Tai‐yi , Yang Bor‐yau , Ko Sheung‐fat , Lee Tze‐yu
Published: August 2002

Transarterial embolization (TAE) using various thrombotic substances for unresectable hepatocellular carcinoma (HCC) performed on many patients has resulted in a better survival rate. We evaluated the efficacy and clinical safety of using an Ethiodol–ethanol mixture as the embolizer for treatment of HCC and the possibility of a surgical approach for inoperable tumors after TAE. Twenty patients with HCC who underwent TAE and tumor resection were included in the study. Initially, eight had increased retention rate of indocyanine green dye via intravenous injection (0.5 mg/kg) at 15 minutes (ICGR15), and six had an insufficient residual volume that precluded them from undergoing tumor resection. TAE was performed by slowly infusing the mixture of Ethiodol and ethanol into the artery supplying the tumor until dual hepatic artery and portal vein embolization was achieved. Serum levels of alanine aminotransferase increased after embolization, but all biochemistry studies reverted to normal within 2 weeks. A decreased tumor size (n= 15), improved ICG (n= 8), and increased volume of the nonembolized lobe (n= 10) were noted. The operations performed were right lobectomy (n= 11), extended right lobectomy (n= 3), left lobectomy (n= 2), extended left lobectomy (n= 2), and wedge resection (n= 2), which included patients who did not want to undergo major hepatectomy. Complete tumor necrosis was found in seven cases. All patients survived with no associated complications. The 1‐year survival rate was 95%. Transarterial Ethiodol and ethanol administration creating dual hepatic artery and portal vein embolization was a safe and efficacious method for treating HCC. It effectively decreases tumor size, causes compensatory hepatic hypertrophy, and improves the ICGR15, which allows a wider range of patients to undergo liver surgery and achieve better survival.
Nonprotruding Colorectal Neoplasms: Epidemiologic Viewpoint
Authors: Rubio Carlos A.
Published: August 2002

Histologic sections from 781 nonprotruding colorectal neoplasias (adenomas and early carcinomas) recorded in Sweden and in Japan were reviewed by the same observer, using strict histologic criteria. Low grade dysplasia (LGD) was present in 82.8% (299/361) of the nonprotruding neoplasms recorded in Sweden but in only 42.6% (179/420) of those recorded in Japan. On the other hand, high grade dysplasia (HGD) was found in 42.4% (178/420) of the nonprotruding colorectal neoplasias in Japanese patients but in only 14.1% (51/361) of those in Swedish patients. Whereas 15.0% (63/420) of the nonprotruding neoplasms in Japan were intramucosal carcinomas (IMCs) or submucosal carcinomas (SMCs), only 3.0% (11/361) of those reviewed in Sweden were IMCs or SMCs. Thus in Japan the lesions were histologically more "advanced" (significantly more lesions had HGD) and more "aggressive" (significantly more lesions were IMC or SMC)
than in Sweden. The cause(s) of that phenomenon remains elusive. The term nonpolypoid adenoma connotes a group of dysplastic lesions with different histologic phenotypes. Interestingly, similar phenotypes were recently found in overt colorectal carcinomas in both Sweden and Japan. Experimental and clinical findings indicate that nonprotruding colorectal adenomas are closely associated with colonic lymphoid nodules, suggesting that the lymphoid‐associated colorectal mucosa might be the birthplace of many nonprotruding adenomas (and consequently of nonprotruding early colorectal carcinomas).
Histopathology of Early Colorectal Cancer
Authors: Jass Jeremy R.
Published: August 2002

The histopathologic spectrum of early colorectal cancer (ECC) is compared from the Western and Japanese perspective. In the West, most ECC presents as a malignant adenoma, whereas superficial ECC with no adenomatous component is well described in the Japanese literature. Furthermore, superficial ECC is thought to progress rapidly and disseminate early. The discrepant viewpoints are considered in the light of different approaches to histopathologic interpretation. Lesions reported by Japanese pathologists as superficial carcinomas limited to the mucosa are diagnosed as flat adenomas in the West. In one Japanese series only 4 of 218 (1.8%) flat or small sessile neoplasms removed by endoscopic mucosal resection were associated with submucosal invasion by carcinoma. Therefore superficial ECC with submucosal spread is uncommon. Most ECC in hereditary nonpolyposis colorectal cancer evolves through the adenoma—carcinoma pathway (including flat adenoma). However, adenoma removal in the context of population‐based screening programs has not lowered the incidence of colorectal cancer; flat colorectal neoplasia may be important in clinical practice.
Radiographic Diagnosis of Early Colorectal Cancer, with Special Reference to the Superficial Type of Invasive Carcinoma
Authors: Maruyama Masakazu , Koizumi Koichi , Kai Shunkichi , Kazami Akira , Handa Takayoshi
Published: August 2002

The possibility of radiographically diagnosing carcinoma with submucosal involvement (invasive carcinoma) is discussed based on 119 invasive carcinomas of the large bowel that had been treated surgically and colonoscopically over a period of 9 years (1989—1997) at the Cancer Institute Hospital in Tokyo. Of these lesions, 38 were superficial‐type invasive carcinoma, accounting for 31.9% (38/119) of all invasive colorectal carcinomas, including 36 lesions (94.7%, 36/38) of types IIa and IIa+IIc and 2 lesions (5.3%, 2/38) of type IIc+IIa. No pure type IIc was seen. The radiographic images obtained were correlated with macroscopic findings and analyzed in terms of visualization of the lesion's contour, central depression, converging folds, and basal indentation. A definitive diagnosis of superficial invasive carcinoma can be made radiographically if a lesion measures 10 mm and reveals moderate to severe basal indentation in a complete or nearly complete profile radiographic image. Attention should be paid to the presence of superficial‐type advanced carcinomas measuring 10 mm or less, which is not infrequently experienced in Japan. Polypoid invasive carcinoma can be definitively diagnosed in the same way with much more certainty than can the superficial type because few polypoid advanced carcinomas are less than 20 mm. The size and the radiographic sign of the basal indentation are the most important indicators for the diagnosis of invasive carcinoma.
Value of Contralateral Surveillance Mammography for Primary Breast Cancer Follow‐up
Authors: Kollias James , Evans Andrew J. , Wilson A. Robin M. , Ellis Ian O. , Elston Christopher W. , Blamey Roger W.
Published: August 2002

Mammographic screening of the contralateral breast is often advocated during follow‐up of women previously treated for primary operable breast cancer. The purpose of this study was to determine the value of this investigation. Between 1987 and 1995 a total of 5102 contralateral screening mammograms were performed biennially on 2511 women aged ≤ 70 years following treatment for primary operable breast cancer. Sixty‐five metachronous contralateral breast cancers were identified: 21 (32%) at routine clinical examination, 24 (37%) at mammography, and 20 (31%) by patients between routine follow‐up appointments. The prognostic features of metachronous cancers were better or similar to those of the first cancer in 59 of 65 (91%) cases. Because of the favorable prognostic characteristics of the contralateral cancer, mammographic screening may have contributed to the long‐term survival of 16 of 26 women in whom the histologic characteristics of the first cancer predicted a good prognosis. The cancer detection rate with mammography for these women was 6.5 per 1000 contralateral mammogram investigations at a cost of £3852 per cancer detected. The results of this study suggest that surveillance mammography of the contralateral breast is of value in women whose first cancer predicted a favorable prognosis.
Débridement of Gunshot Wounds: Semantics and Surgery
Authors: Saadia Roger , Schein Moshe
Published: August 2002

Débridement is a well established modality for management of gunshot wounds. The word “débridement” is originally French. It was used for the first time during the eighteenth century in the surgical context and meant “wound incision.” For French surgeons, it has retained to this day its original meaning. In medical English, though, the use of the term has been marred by persisting confusion about its definition. Two quite different surgical procedures still compete for the definition of débridement: wound incision and wound excision. These procedures are also at the center of a modern controversy about the management of gunshot wounds. The orthodox doctrine, inherited from military surgeons, consists of aggressive tissue excision around the bullet track. This radical policy is being challenged by advocates of a more conservative approach. Minimal tissue excision is sufficient and safe in many cases provided careful monitoring of the wound is instituted. Wound incision alone to relieve tension and allow drainage is possible in certain cases. The tug‐of‐war between excision and incision is outlined herein with reference to the semantic tribulations of the word “débridement” and the implications for patient care.
Is the New Classification of Neuroendocrine Pancreatic Tumors of Clinical Help?
Authors: Schindl Martin , Kaczirek Klaus , Kaserer Klaus , Niederle Bruno
Published: August 2002

A new concept of classifying neuroendocrine pancreatic tumors based on clinicopathologic patterns was summarized recently. To evaluate the clinical reliability and prognostic specificity of this classification system, 100 neuroendocrine pancreatic tumors were retrospectively categorized as “benign,”“uncertain,” and “malignant” based on tumor risk factors (size, local invasion and angioinvasion, cell atypia, metastases) and were followed for disease recurrence and progression. Altogether, 71 functioning tumors (insulinoma, gastrinoma, glucagonoma, enterochromaffin‐like (ECL)oma, somatostatinoma) and 29 nonfunctioning neuroendocrine pancreatic tumors (NETs) were studied. NETs had an increased risk of malignancy (p < 0.05). Tumor size, gross invasion, and metastases correlated significantly with tumor behavior and allowed us to distinguish between “benign” and “malignant” tumors. About 89% of the tumors ≤ 20 mm were “benign,” whereas 71% > 20 mm were “malignant” (p < 0.05). In patients with “benign” and “uncertain” neuroendocrine pancreatic tumors, neither recurrence nor progression of disease was seen. About 41% of the patients with “malignant” tumors died of the disease. The 5‐year estimated cumulative survival of those with “benign” and “uncertain” tumors was 100% and 52 ± 10% for those with “malignant” tumors (p < 0.05). Histomorphologic details classifying the behavior of an “uncertain” tumor are known only after initial treatment and definitive histopathologic investigation. Thus this information is of limited clinical help for treatment strategies.