bluuebunny/crossref_metadata_2025 huggingface dataset:
The Irony of Environmentalism: The Ecological Futility but Political Necessity of Lifestyle Change
Authors: Wapner Paul , Willoughby John
Published: August 2006

Environmentalists argue that we need to reduce population and consumption to protect the environment, and that this is something we can all do by individually choosing to have smaller families and buying fewer products. This article questions the ecological effects of such choice. When people have fewer children or reduce their consumption, they save money. What they then do with this money is crucial to the consequences of their actions. If they place it in conventional financial mechanisms, such as banks or stocks, they merely shift the locale of environmental harm since these mechanisms, within a capitalist economy, redeploy savings into further investment and productivity. For individual lifestyle choices to make a difference, environmentalists must find ways of linking such choices to efforts aimed at changing the nature of capitalist economies. If we had effective public policies that redistributed income, forced polluters to pay for the harm they cause, mandated more environmentally friendly technologies, and reduced the workday in the richer parts of the world, we could alter the way we live our material lives.
Canine neurological diseases in a referral hospital population between 1989 and 2000 in Switzerland
Authors: Fluehmann G. , Doherr M. G. , Jaggy A.
Published: August 2006

Objectives:To merge clinical information from partly overlapping medical record databases of the Small Animal Teaching Hospital of the Vetsuisse Faculty, University of Berne. To describe the frequencies and localisations of neurological diseases in dogs, as well as their age, gender, breed and geographical distributions.

Methods:In this retrospective study, a new database, with specific variables and a diagnosis key list ‘VITAMIN D’, was created and defined. A total of 4497 dogs (average of 375 per year) with a well‐documented neurological disease were included in the study. A key list for the diagnoses was developed and applied to either the presumptive or the clinical and neurohistopathological diagnosis, with a serial number, a code for localisation and a code for differential diagnoses.

Results:Approximately 1159 dogs (26 per cent) had a neurohistopathological diagnosis confirmed, 1431 (32 per cent) had a clinical diagnosis confirmed and 1491 (33 per cent) had a presumptive diagnosis. The most frequent breeds were mixed‐breed dogs (577 of 4497, 13 per cent), followed by German shepherd dogs (466 of 4497, 10 per cent). The most common localisations were the forebrain (908 of 4497, 20 per cent) and the spinal cord at the thoracolumbar area (840 of 4497, 19 per cent). Most dogs were diagnosed with degenerative diseases (38 per cent), followed by inflammatory/infectious diseases (14 per cent). The highest number of submissions originated from geographic regions around the referral hospital and from regions with higher human population densities.

ClinicalSignificance:By defining closed‐list fields and allocating all data to the corresponding fields, a standardised database that can be used for further studies was generated. The analysis of this study gives examples of the possible uses of a standardised database.
Comparison of the accuracy of two ultrasonographic measurements in predicting the parturition date in the bitch
Authors: Beccaglia M. , Luvoni G. C.
Published: August 2006

Objectives:To compare the accuracy of two ultrasonographic measurements, inner chorionic cavity diameter and biparietal diameter, for the prediction of parturition date in small and medium size bitches. The effects of litter size and fetal sex ratio on the accuracy of the prediction were also investigated.

Methods:Ultrasonographic examinations were performed on pregnant bitches and, depending on the stage of pregnancy, the inner chorionic cavity diameter and biparietal diameter were measured. The mean value of the data of each structure was calculated and the predicted day of parturition was obtained by the application of equations derived from growth curves we previously developed for different size bitches.

Results:The parturition term was predicted with similar accuracy during early gestation, by the measurement of inner chorionic cavity diameter, as well as during late gestation, by the measurement of biparietal diameter. Litter size affected only biparietal diameter accuracy, whereas fetal sex ratio did not influence the estimation of the day of parturition.

ClinicalSignificance:Inner chorionic cavity diameter and biparietal diameter were equally reliable parameters in obtaining a reasonably accurate prediction of parturition date at any gestational period at which a bitch is examined.
Localised sarcoptic mange in dogs: a retrospective study of 10 cases
Authors: Pin D. , Bensignor E. , Carlotti D.‐N. , Cadiergues M. C.
Published: August 2006

The authors report 10 cases of localised sarcoptic mange in dogs. In each case, lesions were localised to one precise area of the skin. Pruritus was present in nine cases and absent in one. Affected areas were the feet (one case), the face and/or the pinnae (six cases), the abdominal skin (one case), the flank (one case) and the lumbar area (one case). The types of lesions were erythema, papules, lichenification, scales, crusts and alopecia. Parasites were found in all cases except one, in which anti‐immunoglobulin G Sarcoptes serology was positive. The acaricidal treatments given were lindane, ivermectin or selamectin and were all successful.
Vaginoperitoneal fistula after ovariohysterectomy in three bitches
Authors: Holt P. E. , Bohannon J. , Day M. J.
Published: August 2006

Vaginoperitoneal fistulation was detected in three neutered bitches undergoing retrograde positive contrast vaginourethrography. This is a rarely detected complication of ovariohysterectomy and appears to result in no clinical signs.
Rectovaginal fistula following colectomy with an end‐to‐end anastomosis stapler for a colorectal adenocarcinoma
Authors: Klein A. , Scotti S. , Hidalgo A. , Viateau V. , Fayolle P. , Moissonnier P.
Published: August 2006

An 11‐year‐old, female neutered Labrador retriever was presented with a micro‐invasive differentiated papillar adenocarcinoma at the colorectal junction. A colorectal end‐to‐end anastomosis stapler device was used to perform resection and anastomosis using a transanal technique. A rectovaginal fistula was diagnosed two days later. An exploratory laparotomy was conducted and the fistula was identified and closed. Early dehiscence of the colon was also suspected and another colorectal anastomosis was performed using a manual technique. Comparison to a conventional manual technique of intestinal surgery showed that the use of an automatic staple device was quicker and easier. To the authors’ knowledge, this is the first report of a rectovaginal fistula occurring after end‐to‐end anastomosis stapler colorectal resection‐anastomosis in the dog. To minimise the risk of this potential complication associated with the limited surgical visibility, adequate tissue retraction and inspection of the anastomosis site are essential.
Toy models: The jumping pendulum
Authors: Goriely Alain , Boulanger Philippe , Leroy Jules
Published: August 2006

We consider a simple pendulum consisting of a mass attached to an inextensible string of negligible mass. For small or large initial velocities, the motion of the pendulum is along a circle. When given sufficient but not too large an initial velocity, the mass will reach a certain height and leave the circle. After such a jump, it will follow a parabolic path until the string is again fully extended and the motion is again constrained by the string. We assume that the radial component (along the string) of the velocity of the mass instantaneously vanishes when the string becomes taut and that the mass loses some of its energy in the shock and resumes its circular motion. What is the dynamics of such a pendulum? Can it jump more than once? How many times can it jump?
Electromagnetic braking: A simple quantitative model
Authors: Levin Yan , da Silveira Fernando L. , Rizzato Felipe B.
Published: August 2006

A calculation is presented that quantitatively accounts for the terminal velocity of a cylindrical magnet falling through a long copper or aluminum pipe. The experiment and the theory are a dramatic illustration of Faraday’s and Lenz’s laws.
Staging quantum cryptography with chocolate balls
Authors: Svozil Karl
Published: August 2006

Moderated by a director, laypeople and students assume the role of quanta and enact a quantum cryptographic protocol. The performance is based on a generalized urn model capable of reproducing complementarity even for classical chocolate balls.
Inference of magnetospheric currents from multipoint magnetic field measurements
Authors: Van Allen James A.
Published: August 2006

The European Space Agency has deployed four essentially identical spacecraft into similar near-polar eccentric orbits about the Earth. Each of the four spacecraft carries dual three-axis magnetometers. From simultaneous observations of the magnetic field B at the four vertices of the tetrahedral cluster of spacecraft, it is possible to determine ∇×B and then by Ampere’s law, the local electrical current density J within the plasma of the Earth’s magnetosphere. The purpose of this paper is to illustrate the basic principles of this “curlometer” technique.
Quantum fractal superlattices
Authors: Monsoriu Juan A. , Villatoro Francisco R. , Marín María J. , Pérez Jezabel , Monreal Llúcia
Published: August 2006

Fractal superlattices consist of a series of thin layers of two semiconductor materials alternately deposited on each other with widths corresponding to the rules of construction of a fractal set. The scattering of electrons in superlattices is obtained using the transfer matrix method for generalized Cantor fractal potentials that are characterized by a lacunarity parameter. The numerical results show the self-similarity of the reflection coefficient and the appearance of lacunarity-independent energies with perfectly transparent tunneling due to the bound states of the particle in each of the individual potential wells.
Improving the preparation of K-12 teachers through physics education research
Authors: McDermott Lillian C. , Heron Paula R. L. , Shaffer Peter S. , Stetzer MacKenzie R.
Published: August 2006

Physics education research can contribute to efforts by college and university faculty to improve the preparation of K-12 teachers to teach physics and physical science. Examples from topics included in precollege and university curricula are used to demonstrate the need to help K-12 teachers deepen their understanding of basic physics, to illustrate how research-based instructional materials can assist in this process, and to examine the impact on student learning in K-12 classrooms.
From an idea to a vision: There’s plenty of room at the bottom
Authors: Junk Andreas , Riess Falk
Published: August 2006

Many workers in nanotechnology cite Richard Feynman’s after-dinner speech, “There’s plenty of room at the bottom,” which was given by him on December 29, 1959, to be the birthday of theoretical nanotechnology. This attribution is misleading because there is no direct link from Feynman’s talk to today’s micromachines. We discuss the historical background of Feynman’s talk, the state of the art in 1959, and Feynman’s motivation. We conclude that Feynman was not interested in building miniaturized versions of existing macroscopic machines, but wished to construct microbiological machines and tools that would enable scientists to mimic microbiological materials.
Fourier spectroscopy of ultrashort laser pulses
Authors: Peatross J. , Bergeson S. D.
Published: August 2006

We describe a Fourier-transform spectrometer appropriate for use in an undergraduate optics laboratory. The modular design, which uses off-the-shelf equipment, is suitable for determining the spectra of ultrashort pulsed and continuous light sources. The spectrometer does not require equal step sizes for the motion of the mirror. An algorithm interpolates the phase of both a reference and an unknown light beam at equal intervals before performing the Fourier transform. The interferometer scan and the phase and spectral analysis are performed in a few seconds, making the apparatus a useful tool for teaching concepts of temporal coherence and Fourier spectroscopy.
Dismissing renewed attempts to deny Einstein the discovery of special relativity
Authors: Cerf Roger
Published: August 2006

On the occasion of the centenary of special relativity, several publications have argued that Poincaré, and not Einstein, was the discoverer of special relativity. Attacks have simultaneously been directed at Einstein, whose 1905 article on the electrodynamics of moving bodies was alleged to be a forgery. These attacks praise Lorentz and Poincaré for their results and neglect Poincaré’s failure to make the necessary conceptual leap and understand the fundamental consequences of the principle of relativity. I identify what was missing in Lorentz’s and Poincaré’s views and contrast them with Einstein’s insights.
Illustrating Physics with Ray-Traced Computer Graphics
Authors: Bensky T. J.
Published: August 2006

This paper provides a brief introduction to using ray-traced computer graphics for creating illustrations to be used in physics teaching. The article focuses on Povray, a freely available ray-tracing software program. We have found that a ray-traced illustration produced with this software provides a final-image quality that is far superior to hand-drawn illustrations and those produced using standard click-and-draw computer drawing software. Techniques for illustrating time-dependent scenarios are discussed as well.
Don't Zap that Light Bulb!
Authors: Ray Biswajit
Published: August 2006

Children are often told by their parents not to play with the light switch because every time a light bulb is switched on and off, it costs an extra penny. However, the life of a light bulb under repeated switching is more of a concern than the negligible (estimated to be less than one-thousandth of a penny) additional electricity cost. This brief note explores the connection between the life of a light bulb and the electrical transient associated with switching it on.
Creating a Virtual Ripple Tank in Microsoft Word
Authors: Wagner Judson
Published: August 2006

A ripple tank is an excellent apparatus for displaying the interference pattern generated by circular waves originating from two points in a shallow basin of water. What sets it apart from the interference by sources of sound and light is that it allows the interfering waves to be seen and measured (see Fig. 1). This paper describes a fairly quick way to investigate two-dimensional wave interference on a computer without putting that computer near a wet, sloshing tank of water. Microsoft Word was used for this purpose, although a wide range of other simple drawing programs may be employed.
Angular Speed of a Compact Disc
Authors: Sawicki Mikolaj “Mik”
Published: August 2006

A spinning motion of a compact disc in a CD player offers an interesting and challenging problem in rotational kinematics with a nonconstant angular acceleration that can be incorporated into a typical introductory physics class for engineers and scientists. It can be used either as an example presented during the lecture, emphasizing application of calculus, or as a homework assignment that could be handled easily with the help of a spreadsheet, thus eliminating the calculus aspect altogether. I tried both approaches, and the spreadsheet study was favored by my students.
A Simplified Theoretical Treatment and Simulated Experimental Calculation of the Roche Limit
Authors: LoPresto Michael C.
Published: August 2006

First calculated theoretically in 1850 by French mathematician Eduardo Roche, the Roche limit is the approximate distance from a Jovian planet beyond which moons are found. Within this distance, tidal forces (differential gravitational forces) are stronger than the gravitational binding forces between particles so moons cannot form and instead rings are found. Tidal forces are the differences in gravitation force exerted on different parts of an object due to being different distances from the source. This paper presents a simulation of a scientific experiment. First, a simple expression for the Roche limit, the boundary between the distances from a Jovian planet that the ring systems and moons are found, is derived. A computer simulation of an observation is then used to test the expression “experimentally.”
Toying Around in Physics: A Cross-Curricular Project for Advanced Physics Classes
Authors: Hademenos George J.
Published: August 2006

An effective instructional tool for science teachers, as well as for teachers in any discipline, is to base content and classroom discussions on the experiences of their students. Any concept discussed in class becomes much easier to learn and understand if the student can relate an experience and draw concrete associations between the experience and the concept. This is particularly the case for classroom instruction in physics.
Mariotte Bottle with Side Openings
Authors: Kireš Marián
Published: August 2006

One of the applications of Bernoulli's equation studied in introductory physics courses is that of a liquid, such as water, flowing from an opening in the side of an open tank. The speed of the escaping water is variable: it depends on the height of the free water surface above the opening, and this speed will decrease as the water level drops.
Learning Cycle Model of a Science Lesson
Authors: Nelson Jim , Nelson Jane
Published: August 2006

Editor's note: One of the goals of AAPT is to provide support and encouragement to those new to teaching physics by sharing ideas that experienced physics teachers have found helpful. I hope you will look to this column throughout the year to find help with lesson planning, ideas for classroom management, and opportunities for professional growth. This month's contributing authors, Jane and Jim Nelson, are award-winning physics teachers with years of experience in the classroom, conducting PTRA workshops, and serving as leaders for local, state, and national AAPT organizations. Their contributions to physics teaching are much too numerous to list here, but their joy in sharing ideas with you is typical of the support you will find from AAPT.
Review of a mock research protocol in functional neuroimaging by Canadian research ethics boards
Authors: de Champlain J , Patenaude J
Published: August 2006

Objective:To examine how research ethics boards (REBs) review research projects in emerging disciplines such as functional neuroimaging.

Design:To compare the criteria applied and the decisions reached by REBs that reviewed the same mock research protocol in functional neuroimaging.

Participants:44 Canadian biomedical REBs, mostly working in public university or hospital settings.

Main measurements:The mock research protocol “The Neurobiology of Social Behavior” included several ethical issues operating at all three levels: personal, institutional and social. Data consisting of responses to closed questions were analysed quantitatively. Qualitative analysis of open-question responses used mixed classification.

Results:Similar criteria were used by most participating REBs. Yet the project was unconditionally approved by 3 REBs, approved conditionally by 10 and rejected by 30.

Conclusions:The results point to the difficulty for REBs of reviewing all kinds of research projects, regardless of field, by relying on international and national norms framed in general terms and a possible variation between REBs in the interpretation of their mandate for the protection of research subjects.
Informed consent in neurosurgery—translating ethical theory into action
Authors: Schmitz Dagmar , Reinacher Peter C
Published: August 2006

Objective:Although a main principle of medical ethics and law since the 1970s, standards of informed consent are regarded with great scepticism by many clinicans.

Methods:By reviewing the reactions to and adoption of this principle of medical ethics in neurosurgery, the characteristic conflicts that emerge between theory and everyday clinical experience are emphasised and a modified conception of informed consent is proposed.

Results:The adoption and debate of informed consent in neurosurgery took place in two steps. Firstly, respect for patient autonomy was included into the ethical codes of the professional organisations. Secondly, the legal demands of the principle were questioned by clinicians. Informed consent is mainly interpreted in terms of freedom from interference and absolute autonomy. It lacks a constructive notion of physician–patient interaction in its effort to promote the best interest of the patient, which, however, potentially emerges from a reconsideration of the principle of beneficence.

Conclusion:To avoid insufficient legal interpretations, informed consent should be understood in terms of autonomy and beneficence. A continuous interaction between the patient and the given physician is considered as an essential prerequisite for the realisation of the standards of informed consent.
Enhancing the ethical conduct of genetic research: investigating views of parents on including their healthy children in a study on mild hearing loss
Authors: Gillam L , Poulakis Z , Tobin S , Wake M
Published: August 2006

Clinical genetic research is often regarded as more ethically problematic than other forms of research, and in some countries is subject to specific regulation, requiring researchers to follow specialised guidelines. In this paper, an approach to enhancing the ethical conduct of genetic research is proposed, which is believed to be more effective than simply attempting to follow general guidelines. The potential concerns, likely areas of misunderstanding and negative reactions of the participant group are systematically investigated before starting a study on genetics. This would constitute, in effect, an ethical pilot study, similar to a feasibility pilot study to test equipment, procedures and logistics. The findings of the ethical pilot study would be used to help in designing ethically important aspects of research protocol, such as recruitment procedures, written and other information for potential participants, informed consent processes and reporting of results including ambiguous or uncertain results.
Ethical international research on human subjects research in the absence of local institutional review boards
Authors: Bhat S B , Hegde T T
Published: August 2006

International health-related research on human subjects entails unique ethical responsibilities and difficulties. Often, these difficulties are augmented by the lack of a local ethical review infrastructure. In a recent cross-national study conducted by us, three critical components of ethical regulation were identified—external oversight, local oversight and subject involvement—and integrated into the study design. These three concepts are outlined and established as an important aspect of ensuring ethical coherence in the local context, particularly when reviews by the local institutional review boards cannot practically be obtained. The three levels of ethical oversight identified are suggested to be the framework within which future field studies on human subjects are developed and a standard for maintaining ethical rigorousness in research on humans.
Transhumanism, medical technology and slippery slopes
Authors: McNamee M J , Edwards S D
Published: August 2006

In this article, transhumanism is considered to be a quasi-medical ideology that seeks to promote a variety of therapeutic and human-enhancing aims. Moderate conceptions are distinguished from strong conceptions of transhumanism and the strong conceptions were found to be more problematic than the moderate ones. A particular critique of Boström’s defence of transhumanism is presented. Various forms of slippery slope arguments that may be used for and against transhumanism are discussed and one particular criticism, moral arbitrariness, that undermines both weak and strong transhumanism is highlighted.
Publish and perish: a case study of publication ethics in a rural community
Authors: Fraser J , Alexander C
Published: August 2006

Background:Health researchers must weigh the benefits and risks of publishing their findings.

Objective:To explore differences in decision making between rural health researchers and managers on the publication of research from small identifiable populations.

Method:A survey that investigated the attitudes of Australian rural general practitioners (GPs) to nurse practitioners was explored. Decisions on the study’s publication were analysed with bioethical principles and health service management ethical decision-making models.

Results:Response rate was 78.5% (62/79 GPs). 84–94% of GP responders considered it to be undesirable for nurse practitioners to initiate referrals to medical specialists (n = 58), to initiate diagnostic imaging (n = 56) and to prescribe medication (n = 52).

Bioethical analysis:It was concluded that the principle of beneficence outweighed the principle of non-maleficence and that a valid justification for the publication of these results existed.

Decision-making models of health service managers:On the basis of models of ethical decision making in health service management, the decisions of the area’s health managers resulted in approval to publish this project’s results being denied. This was because the perceived risks to the health service outweighed benefits. Confidentiality could not be ensured by publication under a regional nom de plume.

Conclusions:A conflict of interests between rural researchers and health managers on publication of results is shown by this case study. Researchers and managers at times owe competing duties to key stakeholders. Both weigh the estimated risks and benefits of the effect of research findings. This is particularly true in a rural area, where identification of the subjects becomes more likely.
Should desperate volunteers be included in randomised controlled trials?
Authors: Allmark P , Mason S
Published: August 2006

Randomised controlled trials (RCTs) sometimes recruit participants who are desperate to receive the experimental treatment. This paper defends the practice against three arguements that suggest it is unethical first, desperate volunteers are not in equipoise. Second clinicians, entering patients onto trials are disavowing their therapeutic obligation to deliver the best treatment; they are following trial protocols rather than delivering individualised care. Research is not treatment; its ethical justification is different. Consent is crucial. Third, desperate volunteers do not give proper consent: effectively, they are coerced. This paper responds by advocating a notion of equipoise based on expert knowledge and widely shared values. Where such collective, expert equipoise exists there is a prima facie case for an RCT. Next the paper argues that trial entry does not involve clinicians disavowing their therapeutic obligation; individualised care based on insufficient evidence is not in patients best interest. Finally, it argues that where equipoise exists it is acceptable to limit access to experimental agents; desperate volunteers are not coerced because their desperation does not translate into a right to receive what they desire.
Trust based obligations of the state and physician-researchers to patient-subjects: Figure 1
Authors: Miller P B , Weijer C
Published: August 2006

When may a physician enroll a patient in clinical research? An adequate answer to this question requires clarification of trust-based obligations of the state and the physician-researcher respectively to the patient-subject. The state relies on the voluntarism of patient-subjects to advance the public interest in science. Accordingly, it is obligated to protect the agent-neutral interests of patient-subjects through promulgating standards that secure these interests. Component analysis is the only comprehensive and systematic specification of regulatory standards for benefit-harm evaluation by research ethics committees (RECs). Clinical equipoise, a standard in component analysis, ensures the treatment arms of a randomised control trial are consistent with competent medical care. It thus serves to protect agent-neutral welfare interests of the patient-subject. But REC review occurs prior to enrolment, highlighting the independent responsibility of the physician-researcher to protect the agent-relative welfare interests of the patient-subject. In a novel interpretation of the duty of care, we argue for a “clinical judgment principle” which requires the physician-researcher to exercise judgment in the interests of the patient-subject taking into account evidence on treatments and the patient-subject‘s circumstances.
Why the Kantian ideal survives medical learning curves, and why it matters
Authors: Brecher B
Published: August 2006

The “Kantian ideal” is often misunderstood as invoking individual autonomy rather than rational self legislation. Le Morvan and Stock’s otherwise insightful discussion of “Medical learning curves and the Kantian ideal”—for example—draws the mistaken inference that that ideal is inconsistent with the realities of medical practice. But it is not. Rationally to be a patient entails accepting its necessary conditions.
Hospital based ethics, current situation in France: between “Espaces” and committees
Authors: Guerrier M
Published: August 2006

Unlike research ethics committees, which were created in 1988, the number of functioning hospital based ethical organisations in France, such as clinical ethics committees, is unknown. The objectives of such structures are diverse. A recent law created regional ethical forums, the objectives of which are education, debate, and research in relation to healthcare ethics. This paper discusses the current situation in France and the possible evolution and conflicts induced by this law. The creation of official healthcare ethics structures raises several issues.
Effects of twinning, birth size, and postnatal growth on glucose tolerance and hypothalamic-pituitary-adrenal function in postpubertal sheep
Authors: Bloomfield Frank H. , Oliver Mark H. , Harding Jane E.
Published: August 2006

Low birth weight is associated with postnatal physiological changes, including impaired glucose tolerance and increased cortisol secretion, that may predispose to disease in adulthood. Twins are born lighter than singletons, but there are conflicting data regarding the association between birth weight and postnatal physiology in twins. We studied glucose tolerance and ACTH and cortisol responses to a combined corticotropin-releasing hormone and arginine vasopressin (CRH + AVP) challenge in postpubertal female twin ( n = 7 twin pairs) and singleton ( n = 13) sheep from the same flock. There were no differences in glucose tolerance between twins and singletons and no association with birth weight. Twins had a greater ACTH ( P < 0.05), but not cortisol, response to CRH + AVP than singletons. ACTH area under the curve was inversely related to birth weight in both singletons [ R2 = 0.31, P = 0.05; −8,311 (SD 3,736) pg·min·ml−1·kg−1] and twins ( R2 = 0.49); in twins, this was due to the within-twin pair rather than the between-twin pair coefficient in the regression analysis [ P = 0.02, −26,856 (9,806) vs. P = 0.1, 8,619 (4,950) pg·min·ml−1·kg−1]. We conclude that the reduced fetal growth in twins has postnatal consequences for hypothalamic-pituitary-adrenal function and that this is determined by factors specific to the fetus (within-twin pair) rather than by shared maternal factors (between-twin pair). Studies investigating the associations between fetal growth and postnatal outcomes in twins benefit from an appropriate singleton control group and from analyses evaluating the contribution from both between- and within-pair coefficients in twins.
Chronic PYY3–36 treatment promotes fat oxidation and ameliorates insulin resistance in C57BL6 mice
Authors: van den Hoek Anita M. , Heijboer Annemieke C. , Voshol Peter J. , Havekes Louis M. , Romijn Johannes A. , Corssmit Eleonora P. M. , Pijl Hanno
Published: August 2006

PYY3–36 is a gut-derived hormone acting on hypothalamic nuclei to inhibit food intake. We recently showed that PYY3–36 acutely reinforces insulin action on glucose disposal in mice. We aimed to evaluate effects of PYY3–36 on energy metabolism and the impact of chronic PYY3–36 treatment on insulin sensitivity. Mice received a single injection of PYY3–36 or were injected once daily for 7 days, and energy metabolism was subsequently measured in a metabolic cage. Furthermore, the effects of chronic PYY3–36 administration (continuous and intermittent) on glucose turnover were determined during a hyperinsulinemic-euglycemic clamp. PYY3–36 inhibited cumulative food intake for 30 min of refeeding after an overnight fast (0.29 ± 0.04 vs. 0.56 ± 0.12 g, P = 0.036) in an acute setting, but not after 7 days of daily dosing. Body weight, total energy expenditure, and physical activity were not affected by PYY3–36. However, it significantly decreased the respiratory quotient. Both continuous and intermittent PYY3–36 treatment significantly enhanced insulin-mediated whole body glucose disposal compared with vehicle treatment (81.2 ± 6.2 vs. 77.1 ± 5.2 vs. 63.4 ± 5.5 μmol·min−1·kg−1, respectively). In particular, PYY3–36 treatment increased glucose uptake in adipose tissue, whereas its impact on glucose disposal in muscle did not attain statistical significance. PYY3–36 treatment shifts the balance of fuel use in favor of fatty acids and enhances insulin sensitivity in mice, where it particularly promotes insulin-mediated glucose disposal. Notably, these metabolic effects of PYY3–36 remain unabated after chronic administration, in contrast to its anorexic effects.
Tumor suppressor BRCA1 inhibits a breast cancer-associated promoter of the aromatase gene (CYP19) in human adipose stromal cells
Authors: Ghosh Sagar , Lu Yunzhe , Katz Adam , Hu Yanfen , Li Rong
Published: August 2006

Adipose tissue provides an important extragonadal source of estrogen. Obesity-associated elevation of estrogen production increases risk of breast cancer in postmenopausal women. Aromatase ( CYP19), which converts androgen to estrogen, is a key enzyme in estrogen biosynthesis. In normal adipose tissue, transcription of the aromatase gene is initiated from a relatively weak adipose-specific promoter (I.4). However, in breast cancer, a switch of promoter utilization from I.4 to a strong ovary-specific promoter, PII, leads to increased aromatase expression and, hence, elevated estrogen production. Here, we report an intriguing relationship between the breast cancer susceptibility gene BRCA1 and aromatase expression in human adipose stromal cells (ASCs). Upon stimulation by phorbol ester or dexamethasone, increased aromatase expression in ASCs was accompanied by significant reduction of the BRCA1 level. In addition, adipogenesis-induced aromatase expression was also inversely correlated with BRCA1 abundance. Downregulation of BRCA1 expression in response to various stimuli was through distinct transcription or posttranscription mechanisms. Importantly, siRNA-mediated knockdown of BRCA1 led to specific activation of the breast cancer-associated PII promoter. Therefore, in addition to its well-characterized activities in breast epithelial cells, a role of BRCA1 in modulation of estrogen biosynthesis in ASCs may also contribute to its tissue-specific tumor suppressor function.
Daytime napping after a night of sleep loss decreases sleepiness, improves performance, and causes beneficial changes in cortisol and interleukin-6 secretion
Authors: Vgontzas A. N. , Pejovic S. , Zoumakis E. , Lin H. M. , Bixler E. O. , Basta M. , Fang J. , Sarrigiannidis A. , Chrousos G. P.
Published: August 2006

Sleep loss has been associated with increased sleepiness, decreased performance, elevations in inflammatory cytokines, and insulin resistance. Daytime napping has been promoted as a countermeasure to sleep loss. To assess the effects of a 2-h midafternoon nap following a night of sleep loss on postnap sleepiness, performance, cortisol, and IL-6, 41 young healthy individuals (20 men, 21 women) participated in a 7-day sleep deprivation experiment (4 consecutive nights followed by a night of sleep loss and 2 recovery nights). One-half of the subjects were randomly assigned to take a midafternoon nap (1400–1600) the day following the night of total sleep loss. Serial 24-h blood sampling, multiple sleep latency test (MSLT), subjective levels of sleepiness, and psychomotor vigilance task (PVT) were completed on the fourth (predeprivation) and sixth days (postdeprivation). During the nap, subjects had a significant drop in cortisol and IL-6 levels ( P < 0.05). After the nap they experienced significantly less sleepiness (MSLT and subjective, P < 0.05) and a smaller improvement on the PVT ( P < 0.1). At that time, they had a significant transient increase in their cortisol levels ( P < 0.05). In contrast, the levels of IL-6 tended to remain decreased for ∼8 h ( P = 0.1). We conclude that a 2-h midafternoon nap improves alertness, and to a lesser degree performance, and reverses the effects of one night of sleep loss on cortisol and IL-6. The redistribution of cortisol secretion and the prolonged suppression of IL-6 secretion are beneficial, as they improve alertness and performance.
Structural and functional characterization of bladder smooth muscle in fetal rats with retinoic acid-induced myelomeningocele
Authors: Danzer Enrico , Kiddoo Darcie A. , Redden Robert A. , Robinson Lauren , Radu Antoneta , Zderic Steve A. , Doolin Edward J. , Adzick N. Scott , Flake Alan W.
Published: August 2006

Myelomeningocele (MMC) is the most common cause of neurogenic bladder dysfunction (NBD). We recently developed a novel retinoic acid (RA)-induced MMC model in fetal rats. The objective of this study was to use this model to assess functional and structural characteristics of the detrusor muscle in MMC-associated NBD. Time-dated pregnant Sprague-Dawley rats were gavage fed 60 mg/kg RA dissolved in olive oil or olive oil alone [embryonic day 10 ( E10)]. Bladder specimens from olive oil-exposed fetuses (OIL; n = 71), MMC ( n = 79), and RA-exposed-no MMC (RA, n = 62) were randomly assigned for functional and histopathological evaluation and protein analysis. Contractility responses to field and agonist-mediated stimulation (KCl and bethanecol) were analyzed. The expression patterns of α-smooth muscle actin, myosin, desmin, vimentin, and collagen III and I were analyzed by immunohistochemistry and Western blotting. Spatial and temporal distribution of nerve fibers within the detrusor muscle was monitored by neurotubulin-β-III throughout gestation. Neither OIL, MMC, nor RA detrusor responded to field stimulation. MMC bladder strips showed a significant decrease in contractility after KCl and bethanechol stimulation compared with OIL and RA bladders. Bladder detrusor morphology and expression patterns of smooth muscle markers were similar between groups. Detrusor muscles in OIL and RA fetuses were densely innervated, possessing abundant intramural ganglia and nerve trunks that branch to supply smooth muscle bundles. In MMC bladders, neurotubulin-β-III-positive nerve fibers were markedly decreased with advancing gestational age and were almost completely absent at term ( E22). We conclude that the biomechanical properties of fetal rat MMC bladders are analogous to that seen in humans with MMC-associated NBD. Decreased nerve density indicates loss of peripheral neural innervation throughout gestation. The early observation of decreased innervation and decreased contractility in the absence of morphologic abnormalities in muscle structure or extracellular matrix supports a pathophysiological hypothesis that denervation is the primary insult preceding the observed alterations in bladder muscle structure and function.
Protein kinase B/Akt modulates nephrotoxicant-induced necrosis in renal cells
Authors: Shaik Zabeena P. , Fifer E. Kim , Nowak Grażyna
Published: August 2006

Protein kinase B (Akt) activation is well known for its protective effects against apoptosis. However, the role of Akt in regulation of necrosis is unknown. This study was designed to test whether Akt activation protects against nephrotoxicant-induced injury and death in renal proximal tubular cells (RPTC). Exposure of primary cultures of RPTC to the nephrotoxic cysteine conjugate, S-(1,2-dichlorovinyl)-l-cysteine (DCVC), resulted in 9% apoptosis and 30% necrosis at 24 h following the exposure. Akt was activated during 8 h but not at 24 h following toxicant exposure. No RPTC necrosis was observed during Akt activation. Blocking Akt activation using a phosphatidylinositol 3-kinase inhibitor, LY294002 (20 μM), or expressing dominant negative (inactive) Akt increased DCVC-induced RPTC necrosis to 42%. In contrast, Akt activation by expression of constitutively active Akt diminished necrosis to 15%. Modulation of Akt activity had no effect on DCVC-induced apoptosis. DCVC-induced RPTC injury was accompanied by decreases in respiration (51% of controls) and ATP levels (57% of controls). Akt inhibition exacerbated decreases in RPTC respiration and intracellular ATP content (both to 30% of controls). In contrast, Akt activation reduced DCVC-induced decreases in respiration (80% of controls) and prevented decline in ATP content. These data show that in RPTC, Akt activation reduces 1) toxicant-induced mitochondrial dysfunction, 2) decreases in ATP levels, and 3) necrosis. We conclude that Akt activation plays a protective role against necrosis caused by nephrotoxic insult in RPTC. Furthermore, we identified mitochondria as a subcellular target of protective actions of Akt against necrosis.
Leptospirosis leads to dysregulation of sodium transporters in the kidney and lung
Authors: Andrade Lúcia , Rodrigues Adílson C. , Sanches Talita R. C. , Souza Rodrigo B. , Seguro Antonio Carlos
Published: August 2006

Leptospirosis is a public health problem worldwide. Severe leptospirosis manifests as pulmonary edema leading to acute respiratory distress syndrome and polyuric acute renal failure (ARF). The etiology of leptospirosis-induced pulmonary edema is unclear. Lung edema clearance is largely affected by active sodium transport out of the alveoli rather than by reversal of the Starling forces. The objective of this study was to profile leptospirosis-induced ARF and pulmonary edema. We inoculated hamsters with leptospires and collected 24-h urine samples on postinoculation day 4. On day 5, the animals were killed, whole blood was collected, and the kidneys and lungs were removed. Immunoblotting was used to determine expression and abundance of water and sodium transporters. Leptospirosis-induced ARF resulted in natriuresis, lower creatinine clearance, and impaired urinary concentrating ability. Renal expression of the sodium/hydrogen exchanger isoform 3 and of aquaporin 2 was lower in infected animals, whereas that of the Na-K-2Cl cotransporter NKCC2 was higher. Leptospirosis-induced lesions, predominantly in the proximal tubule, were responsible for the polyuria and natriuresis observed. The polyuria might also be attributed to reduced aquaporin 2 expression and the attendant urinary concentrating defect. In the lungs, expression of the epithelial sodium channel was lower, and NKCC1 expression was upregulated. We found that leptospirosis profoundly influences the sodium transport capacity of alveolar epithelial cells and that impaired pulmonary fluid handling can impair pulmonary function, increasing the chance of lung injury. Greater knowledge regarding sodium transporter dysregulation in the lungs and kidneys can provide new perspectives on leptospirosis treatment.
Fructose-induced metabolic syndrome is associated with glomerular hypertension and renal microvascular damage in rats
Authors: Sánchez-Lozada Laura G. , Tapia Edilia , Jiménez Adriana , Bautista Pablo , Cristóbal Magdalena , Nepomuceno Tomás , Soto Virgilia , Ávila-Casado Carmen , Nakagawa Takahiko , Johnson Richard J. , Herrera-Acosta Jaime , Franco Martha
Published: August 2006

Fructose intake has been recently linked to the epidemic of metabolic syndrome and, in turn, the metabolic syndrome has been epidemiologically linked with renal progression. The renal hemodynamic effects of fructose intake are unknown, as well as the effects of different routes of administration. Metabolic syndrome was induced in rats over 8 wk by either a high-fructose diet (60%, F60, n = 7) or by adding fructose to drinking water (10%, F10, n = 7). Body weight and food and fluid intake of each rat were measured weekly during the follow-up. At baseline and at the end of wk 8, systolic blood pressure, plasma uric acid, and triglycerides were measured. At the end of week 8 glomerular hemodynamics was evaluated by micropuncture techniques. Wall thickening in outer cortical and juxtamedullary afferent arterioles was assessed by immunohistochemistry and computer image analysis. Fructose administration either in diet or drinking water induced hypertension, hyperuricemia, and hypertriglyceridemia; however, there was a progressive increment in these parameters with higher fructose intake (C<F10<F60). In addition, the F60 rats developed kidney hypertrophy, glomerular hypertension, cortical vasoconstriction, and arteriolopathy of preglomerular vessels. In conclusion, fructose-induced metabolic syndrome is associated with renal disturbances characterized by renal hypertrophy, arteriolopathy, glomerular hypertension, and cortical vasoconstriction. These changes are best observed in rats administered high doses (60% diet) of fructose.
Genetic suppression of HO-1 exacerbates renal damage: reversed by an increase in the antiapoptotic signaling pathway
Authors: Olszanecki Rafal , Rezzani Rita , Omura Shinji , Stec David E. , Rodella Luigi , Botros Fady T. , Goodman Alvin I. , Drummond George , Abraham Nader G.
Published: August 2006

Apoptosis has been shown to contribute to the development of acute and chronic renal failure. The antiapoptotic action of the heme oxygenase (HO) system may represent an important protective mechanism in kidney pathology. We examined whether the lack of HO-1 would influence apoptosis in clipped kidneys of two-kidney, one-clip (2K1C) rats. Five-day-old Sprague-Dawley rats were injected in the left ventricle with ≈5 × 109colony-forming units/ml of retrovirus containing rat HO-1 antisense (LSN-RHO-1-AS) or control retrovirus (LXSN). After 3 mo, a 0.25-mm U-shaped silver clip was placed around the left renal artery. Animals were killed 3 wk later. Clipping the renal artery in LSN-RHO-1-AS rats did not result in increased HO-1 expression. In contrast to LXSN animals, 2K1C LSN-RHO-1-AS rats showed increased expression of cyclooxygenase 2 (COX-2) and higher 3-nitrotyrosine (3-NT) content as well as increased expression of the proapoptotic protein Apaf-1 and caspase-3 activity. Clipping the renal artery in LXSN rats resulted in increased expression of the antiapoptotic proteins Bcl-2 and Bcl-xl, while clipping the renal artery in LSN-RHO-1-AS rats did not change Bcl-2 levels and decreased the levels of Bcl-xl. Treatment of LSN-RHO-1-AS rats with cobalt protoporphyrin resulted in induction of renal HO-1, which was accompanied by decreases in blood pressure, COX-2, 3-NT, and caspase-3 activity, and increased expression of anti-apoptotic molecules (Bcl-2, Bcl-xl, Akt and p-Akt) in the clipped kidneys. These findings underscore the prominent role of HO-1 in counteracting apoptosis in this 2K1C renovascular hypertension model.