bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic properties of carbonates: Effects of rock texture and implications for fluid substitution
Authors: Verwer Klaas , Braaksma Hendrik , Kenter Jeroen A.
Published: February 2008

More than 250 plugs from outcrops and three nearby boreholes in an undisturbed reef of Miocene (Tortonian) age were quantitatively analyzed for texture, mineralogy, and acoustic properties. We measured the P- and S-waves of carbonate rocks under dry (humidified) and brine-saturated conditions at [Formula: see text] effective pressure with an ultrasonic pulse transmission technique [Formula: see text]. The data set was compared with an extensive database of petrophysical measurements of a variety of rock types encountered in carbonate sedimentary sequences. Two major textural groups were distinguished on the basis of trends in plots of compressional-wave velocity versus Poisson’s ratio (a specific ratio of P-wave over S-wave velocity). In granular rocks, the framework of depositional grains is the main medium for acoustic-wave propagation; in crystalline rocks, this medium is provided by a framework of interlocking crystals formed during diagenesis. Rock textures are connected to primary depositionalparameters and a diagenetic overprint through the specific effects on Poisson’s ratio. Calculating acoustic velocities using Gassmann fluid substitution modeling approximates measured saturated velocities for 55% of the samples (3% error tolerance); however, it shows considerable errors because shear modulus changes with saturation. Introducing brine into the pore space may decrease the shear modulus of the rock by approximately [Formula: see text] or, alternatively, increase it by approximately [Formula: see text]. This change in shear modulus is coupled with the texture of the rock. In granular carbonates, the shear modulus decreases; in crystalline and cemented carbonates, it increases with saturation. The results demonstrate the intimate relationship between elastic behavior and the depositional and diagenetic properties of carbonate sedimentary rocks. The results potentially allow the direct extraction of granular and crystalline rock texture from acoustic data alone and may help predict rock types from seismic data and in wells.
Object-oriented approach for the pore-scale simulation of DC electrical conductivity of two-phase saturated porous media
Authors: Toumelin Emmanuel , Torres-Verdín Carlos
Published: February 2008

Archie’s empirical power laws are strictly valid only for homogeneous, water-wet (WW) rocks deprived of microporosity or substantial clay-exchange cations. When these conditions are not met, non-Archie electrical behavior arises whereby relationships among rock resistivity, porosity, and water saturation no longer exhibit power-law dependence. Currently, such an unreliable behavior of empirical laws can be quantified only through pore-scale modeling of electrical conductivity under specific sets of geometric assumptions and with substantial computation memory requirements. We introduce a new geometric concept to simulate direct-current electrical-conductivity phenomena in arbitrary rock models on the basis of 3D grain and pore objects that include explicit distributions of intragranular porosity, clay-exchange cations, nonwetting fluid blobs, thin films, and pendular rings. These objects are distributed in the pore space following simple heuristic principles of drainage/imbibition that honorcapillary-pressure curves. They provide a simple way to parameterize the 3D pore space and to calculate the electrical conductivity of porous media saturated with two immiscible fluid phases by way of diffusive random walks within the brine-filled pore space. Not only is the random-walk method memory efficient but it also allows the inclusion of clay/brine cation exchange surfaces otherwise not possible with conventional pore-network models. By comparing results stemming from random-walk, pore-network, and percolation simulations, we show the importance of grain surface roughness and thin film thickness, even in water-wet rocks where those factors usually are neglected. For the case of strongly oil-wet rocks, we show that thin films, snap-offs, and pore microgeometry have a primary impact on hysteresis-dominated rock resistivity during imbibition (increasing water saturation). Our simulation method agrees well overall with percolation simulation results and is advantageously unaffected by assumptions concerning site-percolation imbibition.
Experimental verification of spherical-wave effect on the AVO response and implications for three-term inversion
Authors: Alhussain Mohammed , Gurevich Boris , Urosevic Milovan
Published: February 2008

Spherical-wave offset-dependent reflectivity is investigated by measuring ultrasonic reflection amplitudes from a water/Plexiglas interface. The experimental results show substantial deviation of the measured amplitudes from the plane-wave reflection coefficients at large angles. However, full-wave numerical simulations of the point source reflection response using the reflectivity algorithm show excellent agreement with the measurements, demonstrating that the deviation from the plane-wave response is caused by the wavefront curvature. To analyze the effect of wavefront curvature on elastic inversion, we simulate the spherical-wave reflectivity at different frequencies and invert for elastic parameters by least-square fitting of the plane-wave (Zoeppritz) solution. The results show that the two-parameter inversion based on the intercept and gradient is robust, although estimation of three parameters ([Formula: see text], [Formula: see text], and density) that use the curvature of the offset variation with angle (AVA) response is prone to substantial frequency-dependent errors. We propose an alternative approach to parameter estimation, one that uses critical angles estimated from AVA curves (instead of the AVA curvature). This approach shows a significant improvement in the estimation of elastic parameters, and it could be applied to class 1 AVO responses.
Towards social inclusion in mental health?
Authors: Schneider Justine , Bramley Carole J.
Published: February 2008

This article explores the uses of the terms social exclusion and social inclusion in a mental health context. We briefly describe the origins of the term social exclusion and analyse its connotations in relation to four key dimensions: the relative, multifactorial, dynamic and transactional. We discuss Levitas's three discourses concerning social exclusion (the redistributionist, moral underclass and social integrationist) and present a case in favour of a fourth perspective, societal oppression. Focusing on social inclusion as a remedy for the ills of social exclusion, we discuss implications for contemporary mental health policy, practice and research. We highlight the potential contribution of social psychology to social inclusion theory. We conclude that a better theoretical understanding of causal mechanisms is needed to enable the development of more socially inclusive mental health services.
Perceptions of disadvantage, ethnicity and psychosis
Authors: Cooper Claudia , Morgan Craig , Byrne Majella , Dazzan Paola , Morgan Kevin , Hutchinson Gerard , Doody Gillian A. , Harrison Glynn , Leff Julian , Jones Peter , Ismail Khalida , Murray Robin , Bebbington Paul , Fearon Paul
Published: February 2008

Background

People from Black ethnic groups (African-Caribbean and Black African) are more prone to develop psychosis in Western countries. This excess might be explained by perceptions of disadvantage.

Aims

To investigate whether the higher incidence of psychosis in Black people is mediated by perceptions of disadvantage.

Method

A population-based incidence and case-control study of first-episode psychosis (Aetiology and Ethnicity in Schizophrenia and Other Psychoses (ÆSOP)). A total of 482 participants answered questions about perceived disadvantage.

Results

Black ethnic groups had a higher incidence of psychosis (OR=4.7, 95% CI 3.1–7.2). After controlling for religious affiliation, social class and unemployment, the association of ethnicity with psychosis was attenuated (OR=3.0, 95% CI 1.6–5.4) by perceptions of disadvantage. Participants in the Black non-psychosis group often attributed their disadvantage to racism, whereas Black people in the psychosis group attributed it to their own situation.

Conclusions

Perceived disadvantage is partly associated with the excess of psychosis among Black people living in the UK. This may have implications for primary prevention.
Characteristics of suicides in recent contact with NHS Direct
Authors: Bessant Michael , King Elizabeth A. , Peveler Robert
Published: February 2008

Aims and Method

NHS Direct is increasingly used as a first source of health advice and information, receiving an average of 600 000 calls per month. We performed an audit of suicides in Hampshire and the Isle of Wight over a 2-year period to determine the characteristics of those who died by suicide and had been in recent contact with NHS Direct.

Results

Of 278 suicides resident in Hampshire and the Isle of Wight, 30 (10.8%) had contacted NHS Direct in the preceding year. Of the 30 callers within the preceding year, 12 (40%) made multiple calls, 7 (23%) called within 2 weeks of death, 9 (30%) callers reported mental health problems, 17 (57%) reported physical problems, and 4 (13%) just requested information. Eighteen (60%) calls resulted in urgent medical referral, 17 to a general practitioner and 1 to accident and emergency.

Clinical Implications

The high incidence of physical, often pain-related, problems merits further investigation.
Primary consultation clinics in child psychiatry: an evaluation of referrers' views of the service
Authors: Pathy Puru , Yanamani Neleema , Markantonakis Aristos , Wilson Paul , Mason Russell
Published: February 2008

Aims and Method

To collate referrers' views on primary consultations in child psychiatry, feedback data were collected by questionnaires over a 12-month period.

Results

Referrers found reports clearly written, informative and helpful, but wished for further, more direct involvement, support and follow up, and also for a clear plan of action for the children referred.

Clinical Implications

Primary consultation clinics should be further developed and audited in the future, in view of the recent changes in child and adolescent mental health services.
Regulation of Progesterone Receptor Expression by Estradiol Is Dependent on Age, Sex and Region in the Rat Brain
Authors: Quadros Princy S. , Wagner Christine K.
Published: February 2008

Progesterone receptor (PR) expression is highly dependent on estradiol in the medial preoptic nucleus (MPN) and the ventromedial nucleus (VMN) of the adult rat brain. During development, males express high levels of PR in the MPN, whereas females have virtually no PR, a sex difference resulting entirely from differential exposure to estradiol. Because PR is also estradiol dependent in the adult VMN, the present study examined the regulation of PR immunoreactivity (PRir) in the developing VMN. Surprisingly, PRir was present at high levels in the VMN of both neonatal males and females. In the neonatal VMN, PR expression was dependent on gonadal hormones in males but not females. When females were ovariectomized and exposed to estradiol at various ages from neonatal to adulthood, estradiol reliably induced PRir in the MPN at postnatal d 7 but failed to induce PRir in the VMN of the same animals. Only later in development, around postnatal d 14, did estradiol increase PRir in the female VMN. There appears to be a developmental switch in the VMN when PR expression changes from estradiol independent to estradiol dependent. Furthermore, this switch is anatomically specific and does not exist in the MPN. The present results indicate that the regulation of PR expression by estradiol is dependent on age, sex, and brain region, suggesting that PR may play a critical but specific role in the normal development of these reproductively important brain areas. In addition, the neonatal female VMN may provide a unique model in which to examine the mechanisms underlying the specificity of steroid-induced gene expression.
A Comparison of the Short-Term Effects of Oral Conjugated Equine Estrogens Versus Transdermal Estradiol on C-Reactive Protein, Other Serum Markers of Inflammation, and Other Hepatic Proteins in Naturally Menopausal Women
Authors: Shifren Jan L. , Rifai Nader , Desindes Sophie , McIlwain Marilyn , Doros Gheorghe , Mazer Norman A.
Published: February 2008

Objective: Our objective was to compare the effects of oral vs. transdermal estrogen therapy on C-reactive protein (CRP), IL-6, E- and P-selectin, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule-1, serum amyloid A, transferrin, prealbumin, IGF-I, SHBG, thyroxine-binding globulin (TBG), and cortisol-binding globulin (CBG) in naturally menopausal women.

Design: This was a randomized, open-label crossover clinical trial. A 6-wk withdrawal from prior hormone therapy (baseline) was followed in randomized order by 12-wk oral conjugated equine estrogens (CEEs) (0.625 mg/d) and 12-wk transdermal estradiol (E2) (0.05 mg/d), with oral micronized progesterone (100 mg/d) given continuously during both regimens.

Results: A total of 27 women enrolled, and 25 completed both treatment periods. Nine parameters changed significantly during oral CEE (median percent change from baseline; P value): CRP (192%; P <0.001); E-selectin (−16.3%; P = 0.003); P-selectin (−15.3%; P = 0.012); ICAM-1 (−5%; P = 0.015); transferrin (5.3%; P = 0.024); IGF-I (−30.5%; P < 0.001); SHBG (113%; P < 0.001); TBG (38%; P < 0.001); and CBG (20%; P < 0.001). With transdermal E2, only three parameters changed significantly and to a lesser degree: ICAM-1 (−2.1%; P = 0.04); IGF-I (−12.5%; P < 0.001); and SHBG (2.6%; P = 0.042). During oral CEE the intrasubject changes in CRP correlated strongly with the changes in serum amyloid A (r = 0.805; P < 0.001), and were only weakly associated with the changes in SHBG (r = 0.248; nonsignificant), TBG (0.430; P = 0.031), and CBG (r = 0.072; nonsignificant). The log-log relationship between CRP and IL-6 observed at baseline showed a parallel shift during oral CEE, suggesting an amplified hepatic response or a greater sensitivity to IL-6 stimulation.

Conclusion: Compared with oral CEE, transdermal E2 exerts minimal effects on CRP and the other inflammation and hepatic parameters.
FAK, PDZ-RhoGEF and ROCKII cooperate to regulate adhesion movement and trailing-edge retraction in fibroblasts
Authors: Iwanicki Marcin P. , Vomastek Tomas , Tilghman Robert W. , Martin Karen H. , Banerjee Jayashree , Wedegaertner Philip B. , Parsons J. Thomas
Published: February 2008

A key step in cell migration is the dynamic formation and disassembly of adhesions at the front and the concomitant movement and release of adhesions in the rear of the cell. Fibroblasts maintained in the absence of serum have stable adhesions within the rear of the cell and exhibit reduced trailing-edge retraction resulting in an elongated cell phenotype. Addition of lysophosphatidic acid (LPA) induced the movement of adhesions and retraction of the trailing edge, thus mimicking tail retraction in a migrating cell. Focal adhesion kinase (FAK), guanine nucleotide exchange factors (GEF) for Rho and the Rho effector Rho kinase II (ROCKII) are crucial for the regulation of adhesion movement and trailing-edge retraction. Downregulation of FAK by small interfering RNAs or small hairpin RNAs blocked LPA-induced adhesion movement and restoration of cell shape. This phenotype was rescued by the ectopic expression of PDZ-RhoGEF or a RhoA-effector-domain mutant that activates ROCK. Knockdown of PDZ-RhoGEF or ROCKII inhibited LPA-induced trailing-edge retraction and adhesion movement. Moreover, overexpressed PDZ-RhoGEF co-immunoprecipitated with FAK and localized to FAK-containing adhesions. These studies support a model in which FAK and PDZ-RhoGEF cooperate to induce Rho/ROCKII-dependent focal adhesion movement and trailing-edge retraction in response to LPA.
Visual sensitivity in the crepuscular owl butterfly Caligo memnon and the diurnal blue morpho Morpho peleides: a clue to explain the evolution of nocturnal apposition eyes?
Authors: Frederiksen Rikard , Warrant Eric J.
Published: February 2008

Insects active in dim light, such as moths and many beetles, normally have superposition compound eyes to increase photon capture. But there are nocturnal and crepuscular insects – such as some species of bees, wasps and butterflies – that have apposition compound eyes. These are likely to have adaptations – including large eye and facet size and coarsened spatial and temporal resolution – that improve their sensitivity and thus their visual reliability. Is this also true for crepuscular insects that are active at intermediate intensities? To test this hypothesis, the visual performance of two closely related butterflies, the diurnal blue morpho Morpho peleides and the crepuscular owl butterfly Caligo memnon, were compared. Compared to the diurnal M. peleides, the crepuscular C. memnon does not appear to be adapted to a nocturnal lifestyle in terms of spatial resolution: the interommatidial angleΔϕ is similar in both species, and acceptance angles, Δρ,are only marginally larger in C. memnon. Moreover, temporal resolution is only a little coarser in C. memnon compared to M. peleides. Using a model for sensitivity, we found that the eyes of C. memnon are about four times as light-sensitive as those of M. peleides in the frontal visual field, much of this difference being due to the larger facet diameters found in C. memnon. In summary, greater visual sensitivity has evolved in C. memnon than in M. peleides, showing that adaptations that improve sensitivity can be found not only in nocturnal apposition eyes, but also on a smaller scale in crepuscular apposition eyes.
`Blood-doping' effects on hematocrit regulation and oxygen consumption in late-stage chicken embryos (Gallus gallus)
Authors: Khorrami Sheva , Tazawa Hiroshi , Burggren Warren
Published: February 2008

The extent to which hematocrit (Hct) is regulated and the impact of altered Hct on blood oxygen transport in avian embryos are largely unknown. Consequently, we investigated how acute blood removal or Ringer solution injection modified Hct in day 15 embryos, and how `blood doping' with erythrocyte-enriched whole blood influenced O2 consumption in day 15–17 chicken embryos. Mean Hct (±s.e.m.) at day 15, 16 and 17 was 26.7±0.6%, 28.0±0.4% and 30.7±0.5%, respectively. Blood withdrawal (19 increments of 125 μl each, separated by 30 min) caused a progressive fall in Hct to ∼12% at day 15. Hct decline was strictly proportional to the extent of blood withdrawal. Incremental Ringer solution injection over an 8 h period, transiently increasing blood volume up to 85%over initial values, did not decrease Hct, indicating that injected Ringer solution rapidly left the circulating blood compartment. Blood doping with erythrocyte-enriched whole blood artificially elevated Hct from 27% to 38%,but caused no significant change in routine O2 consumption(0.35–0.39 ml O2 min–1egg–1) at any point over the subsequent 6 h period in day 15–17 embryos. We conclude that Hct is not protected acutely in day 15 chicken embryos, with no evidence of erythrocyte sequestration or release. Additionally, at day 15–17, Hct increases of ∼10% do not enhance embryonic oxygen consumption, suggesting that blood oxygen carrying capacity per se is not limiting to oxygen consumption.
Copper(I) Iodide Accelerates Catalytic Activation in Rhodium Complex-catalyzed Helix-sense-selective Polymerization of Achiral Phenylacetylene Monomers
Authors: Katagiri Hiroo , Kaneko Takashi , Teraguchi Masahiro , Aoki Toshiki
Published: February 2008

Achiral phenylacetylene monomers were polymerized using a rhodium (Rh) complex catalyst in the presence of (S)-1-phenylethylamine. Addition of copper(I) iodide (CuI) into the catalytic system improved the polymer yield. The monomer, which had two hydroxy groups and a hydrogalvinoxyl unit, gave the corresponding polymer with an optically active helical conformation stabilized by intramolecular hydrogen bonding. The chemical oxidation of the polymer yielded the corresponding optically active helical polyradical with high spin concentration.
Re-stocking the resuscitation trolley: how good is compliance with checking procedures?
Authors: Smith Andrea , Kinross James , Bailey Martin , Aggarwal Rajesh , Toresen David , Vincent Charles
Published: February 2008

This study retrospectively reviewed compliance with the checking policy for resuscitation trolleys on medical, surgical and paediatric wards in a large UK city-based teaching hospital. Successful advanced life support (ALS) relies on the availability of a resuscitation trolley that provides the required equipment and recommended drugs. Missing or faulty equipment can significantly compromise ALS. Local policy stipulates periodic checking, and re-stocking as required, of resuscitation trolleys, and checklists are provided for this purpose. The checklist forms located on each trolley were examined between January and December 2005. The frequency of checking was compared with the arrest calls made within that period. The medical, surgical and paediatric wards had a mean checking rate of 72.2%, 68.8% and 65.9%, respectively. In December one ward checked their trolley on 11/31 (35.5%) days of the month, during which there were two cardiac arrest calls. In this hospital, basic trolley checking procedures are not being followed, leaving the trolley unchecked, and possibly unprepared, for an emergency cardiopulmonary arrest. Hospitals should regularly review compliance with policies and procedures for the checking of resuscitation equipment to ensure that appropriate and functioning equipment, and unexpired drugs are in place in all clinical areas.
Improving the Nutritional Status of Elderly Residents of Long-Term Care Homes
Authors: Leydon Noella , Dahl Wendy
Published: February 2008

Introduction

High rates of malnutrition exist in long-term care residents in Canada. Residents may be admitted in a malnourished state or may become malnourished while in care. Nutritional decline of residents may be due to medical conditions but may also result from the failure to provide for the unique nutritional needs of this population, through an inadequate menu, inadequate swallowing and functional assessments, and lack of assistance with dining.

Assessment of problem

A project for the implementation of regional food services policies and practices was deployed with the ultimate goals to reduce nutritional risk and enhance the quality of life of the individuals residing in the 29 long-term care homes in the Saskatoon Health Region. The objectives were: to ensure that food and nutrition staff were competent; to provide adequate nutrition to residents; and to ensure nutrition screening, assessment and appropriate intervention, as approved by the resident or their relatives, was provided. Implementation consisted of: extensive communication of the problem; the development of draft Saskatchewan Food Services policies; planning regional goals, tasks, accountabilities and indicators; delivering meal assistance training to staff; and establishing a Regional Menu Advisory Committee.

Results

Outcomes have been clearly articulated and methods to collect data clearly defined. Interventions in progress include:the development of key relationships among the health region's long-term care staff, managers and directors; communicating a clear understanding of resident-directed care; determining the baseline knowledge of food service staff; and assembling a project tool kit for implementing food and nutrition policies at each home.

Strategies for quality improvement

Although the expectation was that food services policy implementation would be presented to all homes simultaneously, a more intensive pilot schedule has focussed on early-adopter sites. The three-year implementation plan is designed for sustainability.

Lessons and messages

Malnutrition is multifactorial and a concerted effort of all caregivers and service providers is important to address root causes.
Increasing the Involvement of Specialist Physicians in Chronic Disease Management
Authors: Taylor Dylan , Lahey Michele
Published: February 2008

Background

The Capital Health (CH) region in Alberta serves the population of the Edmonton area as well as a large referral population in western Canada. CH is responsible for the delivery of the spectrum of patient care, from inpatient to outpatient services. Growth in outpatient care, in particular, has led to the development of several ambulatory care facilities from which the delivery of care to several populations with a chronic disease will be coordinated.

Assessment of problem

The traditional model of care delivery is unsuited to the management of chronic diseases. Physicians must be part of the planning and implementation of new models if they are to be successful and sustainable. The concept of integration into a delivery team is not well understood or practised. This is not conducive to the integration of specialist physicians into multidisciplinary teams in ambulatory care that serves the needs of patients from a large geographic area.

Results

Chronic disease management using the Chronic Care Model has proven to be an effective method of delivering care to this wide population. Specialist physicians have not always taken advantage of opportunities to be involved in the planning and development of such new health care projects. In CH, physician integration in the planning, development and implementation of this new model has proven vital to its success.

Strategies for change

We based our strategy for change on Wagner's Chronic Care Model. This involved eight steps, the first four of which have been completed and the fifth and sixth are underway.

Lessons and messages

Five factors contributed to the successful integration of specialist physicians in chronic disease management: collaboration between disciplines and organizations; creating patient-centred services; organizational commitments; strong clinical leadership; and early involvement of clinicians.
Written Consent – A Prospective Audit of Practices for ENT Patients
Authors: Berry NH , Phillips JS , Salam MA
Published: February 2008

INTRODUCTION

It is very important that patients are given sufficient time to consider the implications of surgical treatment.

PATIENTS AND METHODS

The authors audited the consenting practices for patients undergoing surgery in a busy ENT unit.

RESULTS

The first cycle demonstrated that 15% of patients were providing written consent for surgery on the same day as their operation. Subsequent to a simple change in departmental policy, this was reduced to 2%. The medicolegal implications of this audit are discussed with reference to current recommendations.

CONCLUSIONS

This simple policy change not only protects the hospital trust from potential litigation but also provides a smooth journey for the patients from diagnosis to making the decision to operate and finally to undergoing surgery.
Rifaximin Treatment for Symptoms of Irritable Bowel Syndrome
Authors: Fumi Andrea L , Trexler Katherine
Published: February 2008

Objective:

To evaluate the role of rifaximin in the treatment of symptoms associated with irritable bowel syndrome (IBS).

Data Sources:

Clinical literature was accessed through MEDLINE (1990–September 2007) using the terms rifaximin, small intestinal bacterial overgrowth (SIBO), bacterial overgrowth, and irritable bowel syndrome. Additionally, references in publications identified in the search were reviewed for relevant information.

Study Selection and Data Extraction:

All articles published in English identified from the data source were evaluated. Randomized clinical trials in adult populations were included.

Data Synthesis:

IBS is a common functional bowel disorder of unknown etiology. Some evidence suggests that symptoms are secondary to bacterial overgrowth in the small intestine. Rifaximin, a nonsystemic antibiotic that targets the gastrointestinal tract, has been evaluated in the treatment of SIBO. Six studies that evaluated rifaximin in either IBS, with or without documented SIBO, or SIBO alone, were reviewed. Significant symptom improvement was reported, and in some cases, correlated with reductions in hydrogen breath tests, suggesting successful treatment of bacterial overgrowth. Data are limited by controversial diagnostic techniques for SIBO, small sample sizes, the unpredictable course of the disorder, and variability in clinical trial methodology that prevents direct comparison.

Conclusions:

Rifaximin offers a potential new therapeutic option for patients with refractory IBS. Larger, well-designed trials are necessary to elucidate the role of rifaximin in the treatment of this disorder.
Considerations for Drug Dosing Post Coronary Artery Bypass Graft Surgery
Authors: Dager William E
Published: February 2008

Acute physiologic changes after bypass graft surgery may temporarily result in reduced drug elimination and dosing requirements for the desired effect. Substantially lower doses for drugs such as the direct thrombin inhibitor argatroban may need to be considered when initiating therapy soon after surgery if the therapeutic window is narrow and impaired liver, kidney, or cardiac function is present. Initial dosing approaches, with follow-up infusion rate adjustments and allowances for the extended time needed to establish and maintain an activated partial thromboplastin time value in the target ratio range, also need to consider the risk of thrombosis or bleeding complications. The duration of reduced dosing may depend on several variables, and, as systems recover, the dosage may need to be adjusted upwards. Retrospective analysis for identifying heparin-induced thrombocytopenia may be difficult in situations where other causes of thrombocytopenia are present, suggesting that posttest scoring methods also be considered to confirm its presence until better, validated methods become available.
A Novel Hemoglobin, Bonn, Causes Falsely Decreased Oxygen Saturation Measurements in Pulse Oximetry
Authors: Zur Berndt , Hornung Andreas , Breuer Johannes , Doll Ulrike , Bernhardt Christine , Ludwig Michael , Stoffel-Wagner Birgit
Published: February 2008

Background: A 4-year-old boy and his father exhibited low oxygen saturation measured transcutaneously by pulse oximetry, a finding that could not be confirmed by arterial blood gas analysis. Both patients exhibited slight hemolysis in their blood, and the boy had a microcytic anemia. There was no evidence of hypoxemia or methemoglobinemia. Despite the normal results from the arterial blood gas analysis, a right-to-left-shunt was assumed in the boy until a cardiology examination excluded this diagnosis. Sleep apnea syndrome was suspected in the father and treated with nocturnal positive pressure respiration based on the low oxygen saturation values obtained with pulse oximetry. Only after consultation with our laboratory was a hemoglobin variant suspected and investigated.

Methods: We performed hemoglobin protein analysis by HPLC, electrophoretic separation, and spectrophotometry and DNA sequence analysis of the α-globin gene.

Results: Both HPLC chromatographic separation and alkaline electrophoresis revealed a unique hemoglobin peak. In both patients, α-globin gene sequencing revealed a mutation resulting in a histidine-to–aspartatic acid substitution at position α87. The low oxygen saturation measurement by pulse oximetry was due to hemoglobin Bonn oxyhemoglobin having an absorption peak at 668 nm, near the 660 nm measured by pulse oximeters.

Conclusion: Hemoglobin Bonn is a novel hemoglobin variant of the proximal α-globin that results in falsely low oxygen saturation measurements with pulse oximetry.
Geoffrey GREATREX/Samuel N. C. LIEU, The Roman Eastern Frontier and the Persian Wars. Part 2: AD 363–630. A Narrative Sourcebook
Authors: Gaube Heinz
Published: February 2008

Nach dem ersten Band dieser Sammlung (The Roman Eastern Frontier and the Persian Wars. AD 226–363. A Documentary History. London 1991), von S. N. C. Lieu und M. H. Dodgeon zusammengestellt, hat der vorliegende Band Informationen zu den Beziehungen zwischen Rom/ Byzanz und den persischen Sasaniden bis unmittelbar vor der arabischen Eroberung Irans (ab 633) zum Gegenstand. Zusammen mit der etwas anders konzipierten Arbeit von E. Winter und B. Dignas (Rom und das Perserreich. Zwei Weltmächte zwischen Konfrontation und Koexistenz. Berlin 2001) verfügen wir nun über drei griffige Hilfsmittel für den Anfängerunterricht, die es uns ermöglichen, die Studenten schnell in die persisch-römisch/byzantinischen Beziehungen zwischen dem 3. und dem frühen 7. Jh. auf der Grundlage einer breiten Quellenübersicht einzuführen. Dafür gebührt den Autoren Anerkennung. Ihre Arbeit wird sicher dazu beitragen, auch nicht direkt mit dem Thema Beschäftigte ein etwas qualifiziertes Verständnis der „Weltpolitik“ zwischen dem 3.und dem 7. Jh. zu ermöglichen. Alle drei Werke sind Lehrbücher, textbooks, jedoch keine wissenschaftlichen Arbeiten im eigentlichen Sinne.
Some aspects of form and function of humor in adolescence
Authors: Führ Martin
Published: February 2008

This study investigates the use, form and function of humor for children aged 12–16 years in two different schools including 47 participants through interviews and 112 participants in a questionnaire. The assumption is made, that developmental changes in form and function of humor for children aged 12–13 years may be influenced by their actual environmental settings and their actual tasks. Data from 12–16 year old children from two schools (school 1, in the countryside with grade 1 to 7 and school 2 in an town area with grade 1 to 10) is analyzed to see whether adult humor appears at an earlier stage in school 1. Finally, the study considers the importance of children's sense of humor in problem solving and social interaction during the period 12–16 years.
Quantitative and Functional Analyses of Spastin in the Nervous System: Implications for Hereditary Spastic Paraplegia
Authors: Solowska Joanna M. , Morfini Gerardo , Falnikar Aditi , Himes B. Timothy , Brady Scott T. , Huang Dongyang , Baas Peter W.
Published: February 2008

Spastin and P60-katanin are two distinct microtubule-severing proteins. Autosomal dominant mutations in the SPG4 locus corresponding to spastin are the most common cause of hereditary spastic paraplegia (HSP), a neurodegenerative disease that afflicts the adult corticospinal tracts. Here we sought to evaluate whether SPG4-based HSP is best understood as a “loss-of-function” disease. Using various rat tissues, we found that P60-katanin levels are much higher than spastin levels during development. In the adult, P60-katanin levels plunge dramatically but spastin levels decline only slightly. Quantitative data of spastin expression in specific regions of the nervous system failed to reveal any obvious explanation for the selective sensitivity of adult corticospinal tracts to loss of spastin activity. An alternative explanation relates to the fact that the mammalian spastin gene has two start codons, resulting in a 616 amino acid protein called M1 and a slightly shorter protein called M85. We found that M1 is almost absent from developing neurons and most adult neurons but comprises 20–25% of the spastin in the adult spinal cord, the location of the axons that degenerate during HSP. Experimental expression in cultured neurons of a short dysfunctional M1 polypeptide (but not a short dysfunctional M85 peptide) is deleterious to normal axonal growth. In squid axoplasm, the M1 peptide dramatically inhibits fast axonal transport, whereas the M85 peptide does not. These results are consistent with a “gain-of-function” mechanism underlying HSP wherein spastin mutations produce a cytotoxic protein in the case of M1 but not M85.
Neural Activity in the Frontal Eye Fields Modulated by the Number of Alternatives in Target Choice
Authors: Lee Kyoung-Min , Keller Edward L.
Published: February 2008

Selection of identical responses may not use the same neural mechanisms when the number of alternatives (NA) for the selection changes, as suggested by Hick's law. For elucidating the choice mechanisms, frontal eye field (FEF) neurons were monitored during a color-to-location choice saccade task as the number of potential targets was varied. Visual responses to alternative targets decreased as NA increased, whereas perisaccade activities increased with NA. These modulations of FEF activities seem closely related to the choice process because the activity enhancements coincided with the timing of target selection, and the neural modulation was greater as NA increased, features expected of neural correlates for a choice process from the perspective of Hick's law. Our current observations suggest two novel notions of FEF neuronal behavior that have not been reported previously: (1) cells called “phasic visual” that do not discharge in the perisaccade interval in a delayed-saccade paradigm show such activity in a choice response task at the time of the saccade; and (2) the activity in FEF visuomotor cells display an inverse relationship between perisaccadic activity and the time of saccade triggering with higher levels of activity leading to longer saccade reaction times. These findings support the area's involvement in sensory-motor translation for target selection through coactivation and competitive interaction of neural populations that code for alternative action sets.
Synapse-Specific Expression of Functional Presynaptic NMDA Receptors in Rat Somatosensory Cortex
Authors: Brasier Daniel J. , Feldman Daniel E.
Published: February 2008

Presynaptic NMDA receptors (NMDARs) modulate release and plasticity at many glutamatergic synapses, but the specificity of their expression across synapse classes has not been examined. We found that non-postsynaptic, likely presynaptic NR2B-containing NMDARs enhanced AMPA receptor-mediated synaptic transmission at layer 4 (L4) to L2/3 (L4–L2/3) synapses in juvenile rat barrel cortex. This modulation was apparent at room temperature when presynaptic NMDARs were activated by elevation of extracellular glutamate or application of exogenous NMDAR agonists. At near physiological temperatures, modulation of transmission by presynaptic NMDARs occurred naturally, without the need for external activation. Blockade of presynaptic NMDARs depressed unitary and extracellularly evoked EPSCs at L4–L2/3 synapses, accompanied by increases in paired-pulse ratio and coefficient of variation, indicative of a decrease in presynaptic release probability. NMDAR agonists increased the frequency of miniature EPSCs in L2/3 neurons, without altering their amplitude or kinetics. Focal application of NMDAR antagonist revealed that the NMDARs that modulate L4–L2/3 transmission are located in L2/3, not L4, consistent with localization on terminals or axons of L4–L2/3 synapses, rather than on the somatodendritic compartment of presynaptic L4 neurons. In contrast, presynaptic NMDARs did not modulate L4–L4 synapses, which originate from the same presynaptic neurons as L4–L2/3 synapses, or cross-columnar L2/3–L2/3 horizontal projections, which synapse onto the same postsynaptic target neurons. Thus, presynaptic NMDARs selectively modulate L4–L2/3 synapses, relative to other synapses made by the same neurons. Existence of these receptors may support specialized processing or plasticity by L4–L2/3 synapses.
Notch Signaling Regulates the Extent of Hair Cell Regeneration in the Zebrafish Lateral Line
Authors: Ma Eva Y. , Rubel Edwin W , Raible David W.
Published: February 2008

Mechanosensory hair cells within the zebrafish lateral line spontaneously regenerate after aminoglycoside-induced death. Exposure of 5-d-old larvae to 400 μmneomycin for 1 h results in death of almost all lateral line hair cells. Regeneration of new hair cells is observed by 24 h after neomycin treatment with nearly complete replacement by 72 h. Using bromodeoxyuridine incorporation, we show that the majority of new hair cells are generated from a transient increase in support cell proliferation that occurs between 12 and 21 h after neomycin damage. Additional observations reveal two distinct subsets of proliferating support cells within the neuromasts that differ in position, morphology, and temporal pattern of proliferation in response to neomycin exposure. We hypothesize that proliferative hair cell progenitors are located centrally within the neuromasts, whereas peripheral support cells may have a separate function. Expression of Notch signaling pathway membersnotch3,deltaA, andatoh1atranscripts are all upregulated within the first 24 h after neomycin treatment, during the time of maximum proliferation of support cells and hair cell progenitor formation. Treatment with a γ-secretase inhibitor results in excess regenerated hair cells by 48 h after neomycin-induced death but has no effect without previous damage. Excess hair cells result from increased support cell proliferation. These results suggest a model where Notch signaling limits the number of hair cells produced during regeneration by regulating support cell proliferation.
Neuron-Specific Expression of Mutant Superoxide Dismutase Is Sufficient to Induce Amyotrophic Lateral Sclerosis in Transgenic Mice
Authors: Jaarsma Dick , Teuling Eva , Haasdijk Elize D. , De Zeeuw Chris I. , Hoogenraad Casper C.
Published: February 2008

Mutations in superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS), an adult-onset progressive paralytic disease characterized by loss of motor neurons, and cause an ALS-like disease when expressed in mice. Recent data have suggested that motor neuron degeneration results from toxic actions of mutant SOD1 operating in both motor neurons and their neighboring glia, raising the question whether mutant SOD1 expression selectively in neurons is sufficient to induce disease. Here we show that neuronal expression of mutant SOD1 is sufficient to cause motor neuron degeneration and paralysis in transgenic mice with cytosolic dendritic ubiquitinated SOD1 aggregates as the dominant pathological feature. In addition, we show that crossing our neuron-specific mutant SOD1 mice with ubiquitously wild-type SOD1-expressing mice leads to dramatic wild-type SOD1 aggregation in oligodendroglia after the onset of neuronal degeneration. Together, our findings support a pathogenic scenario in which mutant SOD1 in neurons triggers neuronal degeneration, which in turn may facilitate aggregate formation in surrounding glial cells.
Induction of Activating Transcription Factors (ATFs) ATF2, ATF3, and ATF4 in the Nucleus Accumbens and Their Regulation of Emotional Behavior
Authors: Green Thomas A. , Alibhai Imran N. , Unterberg Stephen , Neve Rachael L. , Ghose Subroto , Tamminga Carol A. , Nestler Eric J.
Published: February 2008

Previous research has shown that cAMP response element (CRE) binding protein (CREB) in the nucleus accumbens gates behavioral responses to emotional stimuli. For example, overexpression of CREB decreases anxiety, sucrose preference, and sensitivity to drugs of abuse and increases depression-like behavior, whereas blocking CREB via overexpression of inducible cAMP early repressor (ICER) or other dominant-negative inhibitors of CRE-mediated transcription has the opposite effects. However, CREB and ICER are but two members of a larger family of leucine zipper-containing transcription factors composed of multiple products of thecreb,crem(cAMP response element modulator), andatf(activating transcription factor) genes. We demonstrate here that ATF2, ATF3, and ATF4 are each robustly induced in the nucleus accumbens and dorsal striatum by restraint stress or by amphetamine administration. In contrast, little induction is seen for ATF1 or CREM. Using viral-mediated gene transfer, we show that ATF2 overexpression in nucleus accumbens produces increases in emotional reactivity and antidepressant-like responses, a behavioral phenotype similar to that caused by dominant-negative antagonists of CREB. In contrast, ATF3 or ATF4 overexpression in nucleus accumbens decreases emotional reactivity and increases depression-like behavior, consistent with the behavioral phenotype induced by CREB. Because amphetamine and stress induce ATF2, ATF3, and ATF4 in nucleus accumbens, and overexpression of these transcription factors in this brain region in turn alters behavioral responsiveness to amphetamine and stress, our findings support novel roles for these ATF family members in regulating emotional behavior.
Myelinated Skin Sensory Neurons Project Extensively throughout Adult Mouse Substantia Gelatinosa
Authors: Boada M. Danilo , Woodbury C. Jeffery
Published: February 2008

The substantia gelatinosa (SG) of the dorsal horn of the spinal cord is a recipient zone for unmyelinated sensory neurons in adults. Recent studies of the central anatomy of physiologically identified skin sensory neurons in neonatal mice have shown that this region also receives substantial inputs from a variety of myelinated afferents. The present experiments were performed to determine whether these neonatal inputs represent a transient phenotype that retracts from the SG. Studies were conducted in anin vivospinal cord preparation from adult mice; thoracic levels were targeted to facilitate comparisons with previousin vitrofindings. We show that the SG continues to receive substantial projections from myelinated skin sensory neurons throughout life. A large population of myelinated nociceptors conducting in the upper Aδ and low Aβ range maintained extensive projections throughout all areas of the SG well into adulthood; the latter gave rise to dorsally recurving “flame”-shaped arbors extending into the marginal layer that were identical to afferents described in neonates and after nerve injury in adult rats. Furthermore, exquisitely sensitive down hair follicle afferents projected throughout the inner half of the SG (i.e., lamina IIi) and sent dense clusters of terminals well into the outer SG (IIo), where they intermingled with those of unmyelinated nociceptors. Arguments are presented that the SG likely plays a predominant role in tactile processing under normal conditions, but that this role switches rapidly to nociceptive-only during environmental exigencies imposed by temperature extremes.
How Cohabitors View Childbearing
Authors: Sassler Sharon , Cunningham Anna
Published: February 2008

Over one third of all U.S. births are to unmarried women, many cohabiting with their baby's father. While nonmarital childbearing is concentrated among the less educated, in recent decades, its prevalence has increased among those with a high school degree or some college education. This article explores whether cohabitors with some postsecondary schooling challenge normative views regarding marriage as a prerequisite for childbearing. Data are from twenty-four in-depth interviews with childless cohabitors. The majority of respondents intending to have children consider marriage a necessary prerequisite; adherence to this particular sequence is firmest for those with strong aspirations for middle-class status and professional careers. Nonetheless, a considerable share does not view marriage as an imperative, either for parenting or as an end in itself.