bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐Stage Functional Mixed Models for Evaluating the Effect of Longitudinal Covariate Profiles on a Scalar Outcome
Authors: Zhang Daowen , Lin Xihong , Sowers MaryFran
Published: March 2007

Summary The Daily Hormone Study, a substudy of the Study of Women's Health Across the Nation (SWAN) consisting of more than 600 pre‐ and perimenopausal women, includes a scalar measure of total hip bone mineral density (BMD) together with repeated measures of creatinine‐adjusted follicle stimulating hormone (FSH) assayed from daily urine samples collected over one menstrual cycle. It is of scientific interest to investigate the effect of the FSH time profile during a menstrual cycle on total hip BMD, adjusting for age and body mass index. The statistical analysis is challenged by several features of the data: (1) the covariate FSH is measured longitudinally and its effect on the scalar outcome BMD may be complex; (2) due to varying menstrual cycle lengths, subjects have unbalanced longitudinal measures of FSH; and (3) the longitudinal measures of FSH are subject to considerable among‐ and within‐subject variations and measurement errors. We propose a measurement error partial functional linear model, where repeated measures of FSH are modeled using a functional mixed effects model and the effect of the FSH time profile on BMD is modeled using a partial functional linear model by treating the unobserved true subject‐specific FSH time profile as a functional covariate. We develop a two‐stage nonparametric regression calibration method using period smoothing splines. Using the connection between smoothing splines and mixed models, we show that a key feature of our approach is that estimation at both stages can be conveniently cast into a unified mixed model framework. A simple testing procedure for constant functional covariate effect is also proposed. The proposed methods are evaluated using simulation studies and applied to the SWAN data.
Metathetic Reaction in Reverse Micelles: Synthesis of Nanostructured Alkaline‐Earth Metal Phosphates
Authors: Parhi Purnendu , Ray Alok R. , Ramanan Arunachalam
Published: March 2007

For the past few years, hydroxyapatite (HAp) has been identified as a potential biomaterial due to its excellent biocompatibility and bioactivity. The preparation of nanostructured HAp with controlled powder characteristics is a pre‐requisite for processing it into useful biocomposites. Here, the synthesis of nanorods of calcium hydroxyapatite (Ca‐HAp), strontium hydroxyapatite (Sr‐HAp), and barium hydroxyapatite (Ba‐HAp) by exploiting the metathetic reaction taking place in reverse micelles in the presence of cetyltrimethylammonium bromide has been reported. Powder X‐ray diffraction analysis and thermogravimetric measurements confirm the formation of monophasic Ca‐HAp and Sr‐HAp. The growth of nanorods was further confirmed using transmission electron microscopy studies. The average lengths of Ca‐HAp and Sr‐HAp were ∼60 and 30 nm, respectively. However, the preparation of Ba‐HAp invariably yielded a multiphasic mixture with other competitive phases like BaHPO4 and Ba(H2PO4)2.
Life table parameters affecting the population development of the woolly beech aphid, Phyllaphis fagi
Authors: Iversen Trine , Harding Susanne
Published: March 2007

A detailed study of the basic biological parameters affecting the population development of the woolly beech aphid, Phyllaphis fagi L. (Homoptera: Drepanosiphidae), was performed under field and laboratory conditions in order to obtain information about factors responsible for outbreak situations in forest nurseries. In the nurseries, the aphid eggs have found to hatch before budburst. The newly hatched nymphs were highly active in searching for feeding places, which resulted in higher nymph mortality in the first generation than in the following generations. Ten aphid generations were recorded in the nursery during one growing season. In the laboratory, development time, nymph mortality, reproduction, and adult lifetimes were assessed for P. fagi at four constant temperatures, i.e., 12, 15, 20, and 25 °C through four successive generations. Both temperature and aphid generation were found to affect life table parameters. The first generation, however, was less susceptible to changing temperatures than the following generations. Phyllaphis fagi reproductive effort was more dependent on temperature than on aphid generation. No significant difference was found in reproductive effort between apterous and alate females. The potential for outbreak situations therefore exists throughout the summer. The formation of winged morphs was not restricted to a few generations but rather continued for several months, with activity peaking in all years in mid‐June. This had implications for migration to new seedlings in the nurseries. The highest rm value was obtained at 20 °C. Nymphs born at higher temperatures were sometimes born deformed and unable to survive.
Frequency of dermatoses associated with cosmetics
Authors: Duarte Ida , Campos Lage Ana Carolina
Published: March 2007

The objectives of this study were (i) to determine the frequency of dermatoses caused by use of cosmetics in patients with specific complaints of reaction to cosmetic products, and (ii) to observe the main skin conditions frequently misunderstood by users as cosmetic reactions. 176 patients seen in a private office from 1999 to 2006, with complaint of dermatoses caused by cosmetics were examined. The clinical history, physical examination, relation between site of reaction and use of cosmetics were assessed. Of the patients examined, 154 (87.5%) were women and 22 (12.5%) men. About 90 (52%) patients had no skin condition related to cosmetics, 80 (45%) had dermatoses associated with cosmetics, and 6 patients (3%) had inconclusive results. Melasma, contact dermatitis to other products, and acne were the conditions that users associated more often to cosmetics. 14% of patients had skin lesions caused by inappropriate cosmetic use. To conclude, the true adverse reaction to cosmetics was not very common. In this study, dermatitis was associated with cosmetics in only 31% of patients with specific complaint of dermatitis caused by cosmetics. Therefore, 52% of patients misdiagnosed the condition and had other dermatoses, and 14% made inappropriate use of cosmetics.
Long‐lasting patch reactions to gold sodium thiosulfate occurs frequently in healthy volunteers
Authors: Andersen Klaus E. , Jensen Charlotte D.
Published: March 2007

In a skin irritancy study in healthy volunteers with 3 metal salts, aqueous gold sodium thiosulfate (GSTS) in a dilution series caused unexpectedly frequent and strong patch test reactions on volar forearm skin in 22 of 31 participants (71%). The reactions showed morphological features consistent with a contact allergic reaction, and the crescendo type of the response speaks in favour of an allergic nature. Further, 8 of the 31 (26%) developed long‐lasting test reactions. A follow‐up interview among 28/31 participants 10 years later showed that none had experienced long‐term consequences in the form of skin and/or mucosal complaints related to exposure to gold items. The results indicate that inclusion of GSTS in routine patch testing may cause problems regarding interpretation and clinical relevance of positive GSTS patch tests, which fulfil the clinical criteria of a contact allergy.
Selected important fragrance sensitizers in perfumes – current exposures
Authors: Rastogi Suresh Chandra , Johansen Jeanne Duus , Bossi Rossana
Published: March 2007

Contact allergy to fragrance ingredients is frequent. Recommendations and regulations of some of the most frequent and potent fragrance allergens have recently been introduced. To investigate current exposures to 4 important fragrance allergens in hydroalcoholic cosmetic products. 25 popular perfume products of Danish as well as international brands were purchased from the Danish retail market. Contents of 4 important fragrance allergens, isoeugenol, hydroxyisohexyl 3‐cyclohexene carboxaldehyde (HICC, Lyral®), were determined by gas chromatography–mass spectrometry, and atranol and chloroatranol were determined by liquid chromatography–tandem mass spectrometry. Isoeugenol was found in 56%, HICC in 72%, atranol in 59%, and chloroatranol in 36% of the 22 eau de toilette/eau de parfum products. The concentratios of isoeugenol were, in all products, below the recommended maximum concentration of 0.02%. HICC reached a maximum of 0.2%, which is 10‐fold higher than maximum tolerable concentration considered safe by the EU Scientific Committee. The median concentrations of atranol and chloroatranol in the investigated products were similar to those found in similar products in 2003. A significant decrease in the frequency of presence of chloroatranol in the products was observed. There is still a wide‐spread exposure to potent fragrance allergens in perfumes.
Persistence of fish populations in the upper Paraná River: effects of water regulation by dams
Authors: Gubiani É. A. , Gomes L. C. , Agostinho A. A. , Okada E. K.
Published: March 2007

Abstract – River–floodplain systems present intense temporal variations in physical, chemical and biological factors. These variations are closely related to alterations in water levels, which have been attributed to the flood pulse. As several species are strictly related to the flood pulse to fulfil their life cycle, the pulse may be seen as a dispersal mechanism of species onto a floodplain. In this study, we determine how dam construction influenced the persistence ofProchilodus lineatuspopulation, a large migratory fish species from the upper Paraná River floodplain. Data used were collected in two distinct periods, from April 1992 to March 1993 and from January 1999 to December 2001. Fish were collected using seining nets in six (monthly in the first period) and seven (quarterly in the second period) isolated lagoons. The fraction of occupied lagoons was high in the first period (higher than 0.65), when flood was intense. However, in the second period, when the flood pulse did not happen or was short, the fraction of occupied lagoons sharply decreased over time (from 0.85 to 0.22). For the first period, no model fitted to data, but for the second period, a negative linear model (named drought‐dependent model) presented good fit (r2 = 0.97). Therefore, it is possible to infer that long and intense flood pulses are important to maintain the persistence ofP. lineatuspopulations in the floodplain. The artificial control of water levels prompted by dams disrupts this dynamic, reducing persistence to critical levels.
Basin geochemistry and isotopic ratios of fishes and basal production sources in four neotropical rivers
Authors: Jepsen David B. , Winemiller Kirk O.
Published: March 2007

Abstract –  We analysed stable carbon and nitrogen isotopic ratios of dissolved inorganic carbon (DIC), plants, detritus and fishes to estimate the relative importance of dominant production sources supporting food webs of four Venezuelan rivers with divergent geochemical and watershed characteristics. Based on samples taken during the dry season at each site, fishes from two nutrient‐poor, blackwater rivers had significantly lower δ13C values (mean = −31.4‰ and −32.9‰) than fishes from more productive clearwater and whitewater rivers (mean = −25.2‰ and −25.6‰ respectively). Low carbon isotopic ratios of fishes from blackwaters were likely influenced by low δ13C of DIC assimilated by aquatic primary producers. Although floodplains of three savanna rivers supported high biomass of C4 grasses, relatively little carbon from this source appeared to be assimilated by fishes. Most fishes in each system assimilated carbon derived mostly from a combination of microalgae and C3 macrophytes, two sources with broadly overlapping carbon isotopic signatures. Even with this broad overlap, several benthivorous grazers from blackwater and whitewater rivers had isotopic values that aligned more closely with algae. We conclude that comparative stable isotopic studies of river biota need to account for watershed geochemistry that influences the isotopic composition of basal production sources. Moreover, isotopic differences between river basins can provide a basis for discriminating spatial and temporal variation in the trophic ecology of fishes that migrate between watersheds having distinct geochemical characteristics.
Fish assemblages structure and function along environmental gradients in rivers of Gabon (Africa)
Authors: Ibanez C. , Oberdorff T. , Teugels G. , Mamononekene V. , Lavoué S. , Fermon Y. , Paugy D. , Toham A. K.
Published: March 2007

Abstract –  We examined patterns in fish species assemblages structure and function along environmental gradients in rivers of Gabon. Species presence–absence data from 52 sites were first analysed by canonical correspondence analysis. Results showed that the position of sites along the upstream–downstream gradient, together with elevation and water conductance were the most important predictors of local fish assemblage composition. Assemblage richness and trophic structure were further investigated using regression tree analysis. Results revealed a general increase in species richness from upstream to downstream areas and a transition from insectivorous to omnivorous, herbivorous and piscivorous species along this longitudinal gradient. There were several similarities between these previous patterns and those observed in other temperate streams suggesting a potential convergence in fish assemblage along environmental gradients in tropical and temperate riverine systems. From a conservation standpoint, these results highlight the need to evaluate all habitat types along rivers longitudinal gradient to integrate the full spectrum of species assemblages within conservation plans.
Preliminary telemetry data on the movement patterns and habitat use of European catfish (Silurus glanis) in a reservoir of the River Ebro, Spain
Authors: Carol J. , Zamora L. , García‐Berthou E.
Published: March 2007

Abstract –  Knowledge of the movements and diel behaviour of the European catfish (Silurus glanis), the largest European freshwater fish, is limited to anecdotal information. In a preliminary telemetry study of European catfish, the spring diel movement patterns of five adult catfish were examined. After intraperitoneal insertion of the acoustic tags, the positions of the fish were recorded automatically in the Flix Reservoir (River Ebro, NE Spain). A marked nocturnal mobility pattern was observed throughout the study. During daytime, the catfish were consistently located in the littoral zone and spent extended periods of the day hidden in concealed habitats. Catfish movements were in a radial pattern, with upstream and downstream excursions followed by returns to a previously occupied location. Significant individual variations in movement pattern were observed among the tagged fish and within the 24 h cycle for each fish. Mean instantaneous swimming speed was 0.17 body lengths per second (BL·s−1) at night but 0.09 BL·s−1 during the daytime.
Invasion of stream fishes into low trophic positions
Authors: Gido K. B. , Franssen N. R.
Published: March 2007

Abstract –  In the absence of other life‐history constraints, fishes that can feed at low trophic levels (i.e., omnivores/detritivores) are predicted to be successful invaders because their food resources during the colonization and integration phases of the invasion are rarely limiting. Accordingly, we hypothesized that trophic position of non‐native fishes in five mid‐western and south‐western U.S. river systems would be lower than native fishes. By standardizing δ15N values with a common invertebrate (chironomids) across sites, we were able to evaluate differences in trophic position between natives and non‐natives across sample locations and years. Our data tend to support this hypothesis, but there was notable spatial and temporal variation in this pattern. Moreover, three of four species generally fed at lower trophic positions in their introduced ranges than their native ranges. Although many factors influence the success of introduced species, our data suggest that the ability to forage on low‐quality resources is a favourable trait for invasive fishes in lotic systems. Because these fishes feed at low trophic positions, it is important to consider how they will influence invaded systems, in contrast to invaders that feed at higher trophic positions. Future studies that evaluate the resistance of communities to invaders from different trophic positions would help understand the mechanisms that control the establishment and spread of species with different life‐history traits.
Hydroxyethyl starch‐induced itch: Relevance of light microscopic analysis of semi‐thin sections and electron microscopy
Authors: Kamann Stefanie , Flaig Michael J. , Korting Hans Christian
Published: March 2007

Background: Hydroxyethyl starch (HES) is widely used as a plasma substitute for improving microcirculation. A major side effect of HES is severe pruritus caused by HES deposits in the skin. Since specific changes are difficult to see in paraffin sections, electron microscopy is the golden standard technique in the diagnosis of HES‐induced skin disease. Our aim was to compare electron microscopic search for HES deposits with other techniques.

Patients and Methods: During the last ten years, we biopsied 21 patients suspected of having HES‐induced pruritus. We compared conventional microscopy with hematoxylin & eosin and toluidine blue‐stained paraffin sections, toluidine blue‐stained glycide ether‐embedded, semithin sections and transmission electron microscopy.

Results: In 9 patients specific HES deposits could be found by evaluating toluidine blue stained semithin sections by light microscopy alone. In 6 of these cases electron microscopy was also done and confirmed the findings. In contrast, no specific findings due to HES deposits could be detected by conventional histology.

Conclusions: If specific HES deposits are found in toluidine blue‐stained, glycide ether‐embedded semithin sections, electron microscopy is not required.
Congenital dermatofibrosarcoma protuberans: 30 years of follow‐up
Authors: Von Stebut Esther , BrŠuninger Wolfgang
Published: March 2007

Dermatofibrosarcoma protuberans (DFSP) is a rare fibrohistiocytic tumor that commonly appears in adult patients. Few cases of DFSP in childhood have been reported. We describe a case of congenital DFSP that had been incompletely excised in childhood, and again at 28 years of age. The 33‐year‐old woman presented with a recurrence. When comparing the histologic features of the previous specimens excised in 1970 and 30 years later, the similar typical storiform pattern of fibromatous cells was found. The small number of proliferation‐marker‐positive cells was not altered over the course of 30 years. In line with a few additional reports, we suggest that congenital dermatofibrosarcoma protuberans is a tumor with a low malignant potential.
Chronic obstructive pulmonary disease: Diagnosis and management
Authors: Downs Charles A. , Appel Susan J.
Published: March 2007

Purpose: The purpose of this article is to provide a comprehensive review of the current modalities employed in diagnosing and treating chronic obstructive pulmonary disease (COPD). Special emphasis is placed on current guidelines, as defined by the Global Initiative for Chronic Obstructive Lung Disease.

Data source: A comprehensive literature review for COPD serves as the basis for this article.

Conclusions: According to the National COPD Coalition (2004), there are nearly 24 million Americans who suffer from COPD. The incidence of COPD is rising globally and is associated with increased morbidity and mortality. COPD is characterized by progressive decline in function, resulting in concomitant diseases, which increase healthcare dollar expenditures, thus making COPD a concern for healthcare providers in the United States and abroad.

Implications for practice: Once a diagnosis of COPD is made, healthcare providers should explore multiple treatment options in an effort to find the most beneficial regimen. It is only when the treatments are individualized, including physiological therapies and cognitive approaches to lessen risks as well as to reduce exacerbations, that the patient with COPD is able to potentially experience a reasonable quality of life.
T Box Riboswitch Antiterminator Affinity Modulated by tRNA Structural Elements
Authors: Means John A. , Wolf Steffen , Agyeman Akwasi , Burton Jeremy S. , Simson Crystal M. , Hines Jennifer V.
Published: March 2007

A unique RNA–RNA interaction occurs between uncharged tRNA and the untranslated mRNA leader region of bacterial T box genes. The interaction results in activation of a transcriptional antitermination molecular switch (riboswitch) by stabilizing an antiterminator RNA element and precluding formation of a competing transcriptional terminator RNA element. The stabilization requires the base pairing of cognate tRNA acceptor end nucleotides with the antiterminator. To develop an appropriate model system for detailed structural studies and to screen for small molecule disruption of this important RNA–RNA interaction, steady‐state fluorescence measurements of antiterminator model RNAs were used to determine the dissociation constant for model tRNA binding. The antiterminator‐binding affinity for the full, minihelix, microhelix, and tetramer tRNA models differed by orders of magnitude. In addition, not all of the tRNA models exhibited functionally relevant binding specificity. The results from these experiments highlight the importance of looking beyond the level of known base pairing interactions when designing functionally relevant models of riboswitch systems.
Mary Astell's Serious Proposal: Mind, Method, and Custom
Authors: Sowaal Alice
Published: March 2007

In general outline, Astell's A Serious Proposal to the Ladies is well understood. In Part I, Astell argues that women are educable, and she proposes the construction of a women's academy. In Part II, she proposes a method for the improvement of the mind. In this article, I reconstruct and contextualize Astell's arguments and proposals within her theory of mind and her account of the skeptical predicament that she sees as being endemic among women. I argue that Astell's two proposals are best understood as strategies that, when employed, will allow women to critique prejudice and custom.
Neutrophilic dermatosis resembling pyoderma gangrenosum in a dog with polyarthritis
Authors: Bardagí M. , Lloret A. , Fondati A. , Ferrer L.
Published: March 2007

This report describes a case of neutrophilic dermatosis in a dog, with a number of clinical and pathological similarities to human pyoderma gangrenosum. A seven‐year‐old, female German shepherd dog with a history of non‐erosive idiopathic polyarthritis was presented with severe facial swelling, bilateral erosivoulcerative lesions on the muzzle and multiple, eroded, dermal‐subcutaneous nodules on the cranial trunk. Histopathological examination of skin biopsies revealed a necrotising neutrophilic dermatitis. No infectious agents could be detected using specific stains, immunohistochemistry, serology and bacterial aerobic, anaerobic or fungal cultures. A sterile neutrophilic dermatosis resembling human pyoderma gangrenosum was presumptively diagnosed, and the patient showed an excellent response to treatment with prednisone and ciclosporin.
Atypical masticatory muscle myositis in three cavalier King Charles spaniel littermates
Authors: Pitcher G. D. C. , Hahn C. N.
Published: March 2007

This case report describes a novel manifestation of the immune‐mediated disease, masticatory muscle myositis. Clinical signs, including difficulty in opening the mouth (trismus), were seen in three of four 12‐week‐old cavalier King Charles spaniel littermates. Diagnosis was established by 2M immunohistochemistry, supported by characteristic histopathological changes in affected temporal muscle. Treatment using corticosteroids at immune‐modifying doses resulted in resolution of clinical signs in all the affected animals. Masticatory muscle myositis should be considered as a differential diagnosis in groups of young dogs with clinical signs of myositis localised to the head.
Measurement of aldosterone in feline, canine and human urine
Authors: Syme H. M. , Fletcher M. G. R. , Bailey S. R. , Elliott J.
Published: March 2007

Background:Systemic hypertension is an important problem in older cats associated with kidney disease and hypokalaemia, suggesting that excessive activity of the renin‐angiotensin‐aldosterone system might contribute to the hypertensive state. Fluctuations in plasma renin activity and plasma aldosterone concentrations complicate the interpretation of these assays.

Objectives:The aim of this study was to determine whether measurement of urinary aldosterone excretion in cats aided the investigation of hypertension.

Methods:Urine concentrations of free (ethyl acetate extract) and 18‐glucuronidated aldosterone (acid hydrolysis before extraction) were measured by radioimmunoassay in normal, normotensive and hypertensive azotaemic cats (n=11 per group). Urine samples from 11 healthy human volunteers and eight normal dogs were also analysed for comparison. Urinary aldosterone concentration was corrected for the urinary creatinine concentration.

Results:Cats excreted 7·3 times less free aldosterone than human beings, and no free aldosterone was detected in dog urine. Acid hydrolysis led to large increases in aldosterone recovery from both human beings and dog but not feline urine. No significant effect of hypertension or azotaemia on feline urinary aldosterone concentration was found.

ClinicalSignificance:Measurement of aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension.
The Immunopathology of Multiple Sclerosis: An Overview
Authors: Lassmann Hans , Brück Wolfgang , Lucchinetti Claudia F.
Published: March 2007

Multiple sclerosis (MS) is traditionally seen as an inflammatory demyelinating disease, characterized by the formation of focal demyelinated plaques in the white matter of the central nervous system. In this review we describe recent evidence that the spectrum of MS pathology is much broader. This includes demyelination in the cortex and deep gray matter nuclei, as well as diffuse injury of the normal‐appearing white matter. The mechanisms responsible for the formation of focal lesions in different patients and in different stages of the disease as well as those involved in the induction of diffuse brain damage are complex and heterogeneous. This heterogeneity is reflected by different clinical manifestations of the disease, such as relapsing or progressive MS, and also explains at least in part the relation of MS to other inflammatory demyelinating diseases.
Roselle (Hibiscus sabdariffa) Seed Oil Is a Rich Source of γ‐Tocopherol
Authors: Mohamed R. , Fernández J. , Pineda M. , Aguilar M.
Published: March 2007

ABSTRACT:  The antioxidant potential of roselle (Hibiscus sabdariffa L.) extracts was studied. Different plant organs, including seeds, stems, leaves, and sepals, were analyzed with respect to their water‐soluble antioxidant capacity, lipid‐soluble antioxidant capacity, and tocopherol content, revealing that roselle seeds are a good source of lipid‐soluble antioxidants, particularly γ‐tocopherol. Roselle seed oil was extracted and characterized, and its physicochemical parameters are summarized: acidity, 2.24%; peroxide index, 8.63 meq/kg; extinction coefficients at 232 (k232) and 270 nm (k270), 3.19 and 1.46, respectively; oxidative stability, 15.53 h; refractive index, 1.477; density, 0.92 kg/L; and viscosity, 15.9 cP. Roselle seed oil belongs to the linoleic/oleic category, its most abundant fatty acids being C18:2 (40.1%), C18:1 (28%), C16:0 (20%), C18:0 (5.3%), and C19:1 (1.7%). Sterols include β‐sitosterol (71.9%), campesterol (13.6%), Δ‐5‐avenasterol (5.9%), cholesterol (1.35%), and clerosterol (0.6%). Total tocopherols were detected at an average concentration of 2000 mg/kg, including α‐tocopherol (25%), γ‐tocopherol (74.5%), and δ‐tocopherol (0.5%). The global characteristics of roselle seed oil suggest that it could have important industrial applications, adding to the traditional use of roselle sepals in the elaboration of karkade tea.
Excitability of human motor cortex inputs prior to grasp
Authors: Prabhu Gita , Voss Martin , Brochier Thomas , Cattaneo Luigi , Haggard Patrick , Lemon Roger
Published: March 2007

Transcranial magnetic stimulation (TMS) was used to investigate corticospinal excitability during the preparation period preceding visually guided self‐paced grasping. Previously we have shown that while subjects prepare to grasp a visible object, paired‐pulse TMS at a specific interval facilitates motor‐evoked potentials (MEPs) in hand muscles in a manner that varies with the role of the muscle in shaping the hand for the upcoming grasp. This anticipatory modulation may reflect transmission of inputs to human primary motor cortex (M1) for visuomotor guidance of hand shape. Conversely, single‐pulse TMS is known to suppress MEPs during movement preparation. Here we investigate the time course of single‐ and paired‐pulse MEP modulation. TMS was delivered over M1, at different time intervals after visual presentation of either a handle or a disc to healthy subjects. Participants were instructed to view the object, and later to grasp it when given a cue. During grasp there was a specific pattern of hand muscle activity according to the object grasped. MEPs were evoked in these muscles by TMS delivered prior to grasp. Paired‐pulse MEPs were facilitated, whilst single‐pulse MEPs were suppressed. The pattern of facilitation matched the object‐specific pattern of muscle activity for TMS pulses delivered 150 ms or more after object presentation. However, this effect was not present when TMS was delivered immediately after object presentation, or if the delivery of TMS was given separately from the cue to perform the grasp action. These results suggest that object‐related information for preparation of appropriate hand shapes reaches M1 only immediately preceding execution of the grasp.
Differences in spike train variability in rat vasopressin and oxytocin neurons and their relationship to synaptic activity
Authors: Li Chunyan , Tripathi Pradeep K. , Armstrong William E.
Published: March 2007

The firing pattern of magnocellular neurosecretory neurons is intimately related to hormone release, but the relative contribution of synaptic versus intrinsic factors to the temporal dispersion of spikes is unknown. In the present study, we examined the firing patterns of vasopressin (VP) and oxytocin (OT) supraoptic neurons in coronal slices from virgin female rats, with and without blockade of inhibitory and excitatory synaptic currents. Inhibitory postsynaptic currents (IPSCs) were twice as prevalent as their excitatory counterparts (EPSCs), and both were more prevalent in OT compared with VP neurons. Oxytocin neurons fired more slowly and irregularly than VP neurons near threshold. Blockade of Cl− currents (including tonic and synaptic currents) with picrotoxin reduced interspike interval (ISI) variability of continuously firing OT and VP neurons without altering input resistance or firing rate. Blockade of EPSCs did not affect firing pattern. Phasic bursting neurons (putative VP neurons) were inconsistently affected by broad synaptic blockade, suggesting that intrinsic factors may dominate the ISI distribution during this mode in the slice. Specific blockade of synaptic IPSCs with gabazine also reduced ISI variability, but only in OT neurons. In all cases, the effect of inhibitory blockade on firing pattern was independent of any consistent change in input resistance or firing rate. Since the great majority of IPSCs are randomly distributed, miniature events (mIPSCs) in the coronal slice, these findings imply that even mIPSCs can impart irregularity to the firing pattern of OT neurons in particular, and could be important in regulating spike patterning in vivo. For example, the increased firing variability that precedes bursting in OT neurons during lactation could be related to significant changes in synaptic activity.
Role of calsequestrin evaluated from changes in free and total calcium concentrations in the sarcoplasmic reticulum of frog cut skeletal muscle fibres
Authors: Pape Paul C. , Fénelon Karine , Lamboley Cédric R. H. , Stachura Dorothy
Published: March 2007

Calsequestrin is a large‐capacity Ca‐binding protein located in the terminal cisternae of sarcoplasmic reticulum (SR) suggesting a role as a buffer of the concentration of free Ca in the SR ([Ca2+]SR) serving to maintain the driving force for SR Ca2+ release. Essentially all of the functional studies on calsequestrin to date have been carried out on purified calsequestrin or on disrupted muscle preparations such as terminal cisternae vesicles. To obtain information about calsequestrin's properties during physiological SR Ca2+ release, experiments were carried out on frog cut skeletal muscle fibres using two optical methods. One – the EGTA–phenol red method – monitored the content of total Ca in the SR ([CaT]SR) and the other used the low affinity Ca indicator tetramethylmurexide (TMX) to monitor the concentration of free Ca in the SR. Both methods relied on a large concentration of the Ca buffer EGTA (20 mm), in the latter case to greatly reduce the increase in myoplasmic [Ca2+] caused by SR Ca2+ release thereby almost eliminating the myoplasmic component of the TMX signal. By releasing almost all of the SR Ca, these optical signals provided information about [CaT]SR versus [Ca2+]SR as [Ca2+]SR varied from its resting level ([Ca2+]SR,R) to near zero. Since almost all of the Ca in the SR is bound to calsequestrin, this information closely resembles the binding curve of the Ca–calsequestrin reaction. Calcium binding to calsequestrin was found to be cooperative (estimated Hill coefficient = 2.95) and to have a very high capacity (at the start of Ca2+ release, 23 times more Ca was estimated to initiate from calsequestrin as opposed to the pool of free Ca in the SR). The latter result contrasts with an earlier report that only ∼25% of released Ca2+ comes from calsequestrin and ∼75% comes from the free pool. The value of [Ca2+]SR,R was close to the KD for calsequestrin, which has a value near 1 mm in in vitro studies. Other evidence indicates that [Ca2+]SR,R is near 1 mm in cut fibres. These results along with the known rapid kinetics of the Ca–calsequestrin binding reaction indicate that calsequestrin's properties are optimized to buffer [Ca2+]SR during rapid, physiological SR Ca2+ release. Although the results do not entirely rule out a more active role in the excitation–contraction coupling process, they do indicate that passive buffering of [Ca2+]SR is a very important function of calsequestrin.
Functional source separation and hand cortical representation for a brain–computer interface feature extraction
Authors: Tecchio Franca , Porcaro Camillo , Barbati Giulia , Zappasodi Filippo
Published: March 2007

A brain–computer interface (BCI) can be defined as any system that can track the person's intent which is embedded in his/her brain activity and, from it alone, translate the intention into commands of a computer. Among the brain signal monitoring systems best suited for this challenging task, electroencephalography (EEG) and magnetoencephalography (MEG) are the most realistic, since both are non‐invasive, EEG is portable and MEG could provide more specific information that could be later exploited also through EEG signals. The first two BCI steps require set up of the appropriate experimental protocol while recording the brain signal and then to extract interesting features from the recorded cerebral activity. To provide information useful in these BCI stages, our aim is to provide an overview of a new procedure we recently developed, named functional source separation (FSS). As it comes from the blind source separation algorithms, it exploits the most valuable information provided by the electrophysiological techniques, i.e. the waveform signal properties, remaining blind to the biophysical nature of the signal sources. FSS returns the single trial source activity, estimates the time course of a neuronal pool along different experimental states on the basis of a specific functional requirement in a specific time period, and uses the simulated annealing as the optimization procedure allowing the exploit of functional constraints non‐differentiable. Moreover, a minor section is included, devoted to information acquired by MEG in stroke patients, to guide BCI applications aiming at sustaining motor behaviour in these patients. Relevant BCI features – spatial and time‐frequency properties – are in fact altered by a stroke in the regions devoted to hand control. Moreover, a method to investigate the relationship between sensory and motor hand cortical network activities is described, providing information useful to develop BCI feedback control systems. This review provides a description of the FSS technique, a promising tool for the BCI community for online electrophysiological feature extraction, and offers interesting information to develop BCI applications to sustain hand control in stroke patients.
Showing Some Skin
Authors: Al-Awqati Qais
Published: March 2007

Skin
. A Natural History.
By Nina G. Jablonski
. University of California Press, Berkeley, CA, 2006. 293 pp. $24.95, £15.95. ISBN 9780520242814.

The author discusses the characteristics, functions, evolutionary history, and possible future of the human integument.
Occupational risk factors for asthma among nurses and related healthcare professionals in an international study
Authors: Mirabelli Maria C , Zock Jan-Paul , Plana Estel , Antó Josep Maria , Benke Geza , Blanc Paul D , Dahlman-Höglund Anna , Jarvis Deborah L , Kromhout Hans , Lillienberg Linnéa , Norbäck Dan , Olivieri Mario , Radon Katja , Sunyer Jordi , Torén Kjell , van Sprundel Marc , Villani Simona , Kogevinas Manolis
Published: March 2007

Objective:The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II).

Methods:In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (n = 2481).

Results:Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% CI 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% CI 1.03 to 4.53).

Conclusions:In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.
Contraction-mediated glucose uptake is increased in men with impaired glucose tolerance
Authors: Skov-Jensen Camilla , Skovbro Mette , Flint Anne , Helge Jørn Wulff , Dela Flemming
Published: March 2007

Exercise superimposed on insulin stimulation is shown to increase muscle glucose metabolism and these two stimuli have synergistic effects. The objective of this study was to investigate glucose infusion rates (GIR) in groups with a wide variation in terms of insulin sensitivity during insulin stimulation alone and with superimposed exercise. Patients with type 2 diabetes, subjects with impaired glucose tolerance (IGT), healthy controls, and endurance-trained subjects were studied. The groups were matched for age and lean body mass (LBM), and differed in peak oxygen uptake (VO2 peak), body fat percentage, body mass index (BMI), fasting plasma glucose concentration, and oral glucose-tolerance test (OGTT). Each subject underwent a two-step sequential hyperinsulinemic, euglycemic clamp. During the last 30 min of the 2nd clamp step, subjects exercised on a bicycle at 43% ± 2% of VO2 peak. In agreement with the OGTT data, the presence of different GIR during insulin stimulation alone demonstrated varying levels of insulin sensitivity between groups. However, the impairment of GIR in IGT observed during insulin stimulation alone was abolished compared to controls when exercise was superimposed on insulin stimulation. Humans with IGT are resistant to insulin-stimulated but not to exercise-induced glucose uptake.
Physical activity in prevention and treatment of the metabolic syndrome
Authors: Lakka Timo A. , Laaksonen David E.
Published: March 2007

Randomised controlled trials have shown that exercise training has a mild or moderate favourable effect on many metabolic and cardiovascular risk factors that constitute or are related to the metabolic syndrome (MetS). Epidemiological studies suggest that regular physical activity prevents type 2 diabetes, cardiovascular disease, and premature mortality in large part through these risk factors. Although randomized controlled trials with the prevention or treatment of the MetS as the main outcome have not been published, several large randomized controlled trials provide strong evidence that favourable lifestyle changes, including regular physical activity, are effective in the prevention of type 2 diabetes in individuals who are overweight and have impaired glucose tolerance. Compliance with the current recommendations to increase the total volume of moderate-intensity physical activity and to maintain good cardiorespiratory and muscular fitness appears to markedly decrease the likelihood of developing the MetS, especially in high-risk groups. Walking is the most common form of physical activity— it improves health in many ways and is generally safe. Therefore, brisk walking for at least 30 min daily can be recommended as the principal form of physical activity at the population level. If there are no contraindications, more vigorous physical exercise or resistance training should also be considered to obtain additional health benefits. Unstructured and low-intensity physical activity may also decrease the likelihood of developing the MetS, especially when substituted for sedentary behaviours such as watching television. The measurement of maximal oxygen consumption may provide an efficient means to target even individuals with relatively few metabolic risk factors who may benefit from more intensive intervention.
Cause-effect relationships between zymogen activation and other early events in secretagogue-induced acute pancreatitis
Authors: Van Acker Gijs J. D. , Weiss Eric , Steer Michael L. , Perides George
Published: March 2007

We have hypothesized that the colocalization of digestive zymogens with lysosomal hydrolases, which occurs during the early stages of every experimental pancreatitis model, facilitates activation of those zymogens by lysosomal hydrolases such as cathepsin B and that this activation triggers acute pancreatitis by leading to acinar cell injury. Some, however, have argued that the colocalization phenomenon may be the result, rather than the cause, of zymogen activation during pancreatitis. To resolve this controversy and explore the causal relationships between zymogen activation and other early pancreatitis events, we induced pancreatitis in mice by repeated supramaximal secretagogue stimulation with caerulein. Some animals were pretreated with the cathepsin B inhibitor CA-074me to inhibit cathepsin B, prevent intrapancreatic activation of digestive zymogens, and reduce the severity of pancreatitis. We show that inhibition of cathepsin B by pretreatment with CA-074me prevents intrapancreatic zymogen activation and reduces organellar fragility, but it does not alter the caerulein-induced colocalization phenomenon or subcellular F-actin redistribution or prevent caerulein-induced activation of NF-κB, ERK1/2, and JNK or upregulated expression of cytochemokines. We conclude 1) that the colocalization phenomenon, F-actin redistribution, activation of proinflammatory transcription factors, and upregulated expression of cytochemokines are not the results of zymogen activation, and 2) that these early events in pancreatitis are not dependent on cathepsin B activity. In contrast, zymogen activation and increased subcellular organellar fragility during caerulein-induced pancreatitis are dependent on cathepsin B activity.
Functional evidence for Na+-activated K+ channels in circular smooth muscle of the opossum lower esophageal sphincter
Authors: Zhang Yong , Paterson William G.
Published: March 2007

Na+ reduction induces contraction of opossum lower esophageal sphincter (LES) circular smooth muscle strips in vitro; however, the mechanism(s) by which this occurs is unknown. The purpose of the present study was to investigate the electrophysiological effects of low Na+ on opossum LES circular smooth muscle. In the presence of atropine, quanethidine, nifedipine, and substance P, conventional intracellular electrodes recorded a resting membrane potential (RMP) of −37.5 ± 0.9 mV ( n = 4). Decreasing [Na+] from 144.1 to 26.1 mM by substitution of equimolar NaCl with choline Cl depolarized the RMP by 7.1 ± 1.1 mV. Whole cell patch-clamp recordings revealed outward K+ currents that began to activate at −60 mV using 400-ms stepped test pulses (−120 to +100 mV) with increments of 20 mV from holding potential of −80 mV. Reduction of [Na+] in the bath solution inhibited K+ currents in a concentration-dependent manner. Single channels with conductance of 49–60 pS were recorded using cell-attached patch-clamp configurations. The channel open probability was significantly decreased by substitution of bath Na+ with equimolar choline. A 10-fold increase of [K+] in the pipette shifted the reversal potential of the single channels to the positive by −50 mV. These data suggest that Na+-activated K+ channels exist in the circular smooth muscle of the opossum LES.
Causes of excitation-induced muscle cell damage in isometric contractions: mechanical stress or calcium overload?
Authors: Fredsted Anne , Gissel Hanne , Madsen Klavs , Clausen Torben
Published: March 2007

Prolonged or unaccustomed exercise leads to muscle cell membrane damage, detectable as release of the intracellular enzyme lactic acid dehydrogenase (LDH). This is correlated to excitation-induced influx of Ca2+, but it cannot be excluded that mechanical stress contributes to the damage. We here explore this question using N-benzyl- p-toluene sulfonamide (BTS), which specifically blocks muscle contraction. Extensor digitorum longus muscles were prepared from 4-wk-old rats and mounted on holders for isometric contractions. Muscles were stimulated intermittently at 40 Hz for 15–60 min or exposed to the Ca2+ionophore A23187. Electrical stimulation increased45Ca influx 3–5 fold. This was followed by a progressive release of LDH, which was correlated to the influx of Ca2+. BTS (50 μM) caused a 90% inhibition of contractile force but had no effect on the excitation-induced45Ca influx. After stimulation, ATP and creatine phosphate levels were higher in BTS-treated muscles, most likely due to the cessation of ATP-utilization for cross-bridge cycling, indicating a better energy status of these muscles. No release of LDH was observed in BTS-treated muscles. However, when exposed to anoxia, electrical stimulation caused a marked increase in LDH release that was not suppressed by BTS but associated with a decrease in the content of ATP. Dynamic passive stretching caused no increase in muscle Ca2+content and only a minor release of LDH, whereas treatment with A23187 markedly increased LDH release both in control and BTS-treated muscles. In conclusion, after isometric contractions, muscle cell membrane damage depends on Ca2+influx and energy status and not on mechanical stress.