bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical and emotional disturbances in children with adenotonsillar hypertrophy
Authors: Kurnatowski P , Putyński L , Łapienis M , Kowalska B
Published: February 2008

Objective:

Enlarged tonsils and adenoids (part of Waldeyer's ring) are responsible for obstructive sleep disordered breathing. Obstructive sleep disordered breathing episodes lead to hypoxaemia, hypercapnia and a state of arousal, all of which affect normal development of the nervous system. In this study, two hypotheses were tested: (1) obstructive sleep disordered breathing is caused by adenotonsillar hypertrophy and is associated with hypoxia and brain dysfunction; and (2) children with obstructive sleep disordered breathing more commonly display emotional lability, depressive behaviour and anxiety.

Material and methods:

A total of 225 children were examined. The study group consisted of 121 children with adenotonsillar hypertrophy (87 aged six to nine years and 34 aged 10 to 13 years) and with obstructive sleep apnoeas and hypopnoeas confirmed by polysomnography. Patients were compared with 104 children with no obstructive sleep disordered breathing and no adenotonsillar hypertrophy (74 aged six to nine years and 30 aged 10 to 13 years). The following tests were used to measure the children's emotional disorders: the children's depression inventory; the state-trait anxiety inventory for children; and the emotional instability scale. The average values and standard deviations were calculated for all results. Student's t-test was used to compare differences in all groups of children. The minimum level of p < 0.05 was set as statistically significant.

Results:

Children with adenotonsillar hypertrophy are more likely to experience poor brain development and sleep problems. They also have emotional disturbances. In the sick and healthy children aged six to nine years, mean results for the emotional instability scale were statistically significantly different in the two groups, being higher in children with adenotonsillar hypertrophy than in healthy children. Mean values for the children's depression inventory test were higher in children with adenotonsillar hypertrophy, but the differences were not statistically significant. In the state-trait anxiety inventory for children test, the mean T score was T = 1.760 and the level of significance was p = 0.08 for both groups. Since the standard level of significance was p < 0.05, the differences in mean values for the state-trait anxiety inventory for children test bordered on statistical significance. There were no differences between tests results in the older children (10 to 13 years).

Conclusions:

Recent studies have confirmed the negative emotional effect of adenotonsillar hypertrophy induced obstructive sleep disordered breathing in children aged six to nine years. The main problems are emotional lability, and anxiety and depressive disturbances. Such emotional problems subside in older children (aged 10 to 13 years).
Immunolocalisation of heme oxygenase isoforms in human nasal polyps
Authors: Lo S , Di Palma S , George E , McCombe A W
Published: February 2008

Background:

Carbon monoxide is an endogenous vasodilator gas produced by the enzyme heme oxygenase (HO). HO is expressed in human nasal mucosa, but its pathophysiological role in nasal inflammatory diseases is not fully understood. The aim of this study was to detect and compare the expression of HO-1 and -2 isoforms in nasal polyps with normal nasal mucosa.

Methods:

Immunohistochemical analysis using antibodies specific for HO-1 and -2 was conducted on nasal polyps from nine patients with allergic nasal polyposis, and on normal nasal mucosa from six controls.

Results:

Intense HO-1 immunoreactivity was observed in nasal polyp epithelium but was absent in normal nasal mucosa. HO-2 staining was observed in respiratory epithelium, vascular endothelium and seromucous glands, with no difference observed between nasal polyps and normal nasal mucosa.

Conclusions:

HO-1 expression is up-regulated in nasal polyp epithelium, supporting the theory that respiratory epithelium plays a role in the pathogenesis of nasal polyposis.
Effectiveness of X-ray and computed tomography screening for assessing pulmonary involvement in patients with head and neck squamous cell carcinoma
Authors: Leong S C L , Javed F , Elliot S , Mortimore S
Published: February 2008

Objectives:

To evaluate the benefits of chest computed tomography and X-ray as screening tools in patients with newly diagnosed head and neck squamous cell carcinoma, to determine the incidence of lung metastases or synchronous pulmonary lesions, and to evaluate factors associated with positive radiological findings.

Design:

Five-year, retrospective survey of all newly diagnosed cases of head and neck squamous cell carcinoma.

Results:

We included 102 patients (63 men and 39 women), with a mean age of 67 years (range 33–91 years). The incidence of pulmonary involvement was 17 per cent. The sensitivity and specificity of computed tomography were 100 and 89.8 per cent, respectively. For chest X-ray, the sensitivity was 35.7 per cent and the specificity 92.7 per cent. The accuracy of computed tomography was 91.5 per cent and that of chest X-ray 83.1 per cent. There was a clear correlation between higher nodal stage and larger tumour with the development of distant metastases. In patients with a positive chest computed tomography scan, 86 per cent had T3or T4tumours, in contrast to 38 per cent of those with a negative chest scan (p < 0.05). In addition, 71 per cent of patients with positive findings had N2or N3nodal disease, compared with 29 per cent of those with negative findings (p < 0.05).

Conclusion:

There is currently no consensus on the use of chest X-ray and computer tomography for screening newly diagnosed cases of head and neck squamous cell carcinoma. We recommend routine scanning of high-staged head and neck squamous cell carcinoma. The National Institute of Health and Clinical Excellence guidelines should be reappraised.
Complete recovery of an isolated left vocal fold palsy associated with a benign mediastinal thymic cyst
Authors: Woolley S L , Espeso A , Smith D R K
Published: February 2008

Objectives:

To present a case of benign mediastinal thymic cyst, and to review the published information on these cysts, including their incidence, presentation, diagnosis and management.

Methods:

We report the case of a 55-year-old man who presented with a unilateral vocal fold palsy subsequently found to be due to the presence of a benign mediastinal thymic cyst. A literature search was undertaken to identify the incidence, key features and management of this rare condition.

Results:

Benign mediastinal thymic cysts are a rare cause of mediastinal masses. Usually diagnosed incidentally, their management is usually surgical. Vocal fold palsy in isolation has not previously been reported in association with mediastinal thymic cysts.

Conclusion:

This report describes what we believe to be the first published case of a completely reversible vocal fold palsy presenting in association with a rare benign mediastinal thymic cyst.
Inner-ear obliteration in ulcerative colitis patients with sensorineural hearing loss
Authors: Kariya S , Fukushima K , Kataoka Y , Tominaga S , Nishizaki K
Published: February 2008

Objective:

Systemic autoimmune diseases, including ulcerative colitis, may involve the inner ear. Several ulcerative colitis cases presenting with sensorineural hearing loss have been reported. We report the T2-weighted, three-dimensional, inner-ear magnetic resonance imaging findings in the inner ears of two such patients.

Methods:

Case reports and a review of the literature concerning autoimmune disease and sensorineural hearing loss are presented.

Results:

We describe two cases of ulcerative colitis with sensorineural hearing loss in which three-dimensional magnetic resonance imaging revealed obliteration of the inner ear. Those inner ears with obliteration had severe hearing loss, and responded poorly to steroid therapy.

Conclusion:

To our knowledge, there has been no previous published report of the T2-weighted, inner-ear magnetic resonance imaging findings of cases of ulcerative colitis with sensorineural hearing loss. This paper represents the first published report in the world literature of inner-ear obliteration in such patients. Three-dimensional magnetic resonance imaging is beneficial in elucidating the pathophysiology of the inner-ear involvement seen in ulcerative colitis.
Surgical treatment of osteoradionecrosis of the temporal bone in patients with nasopharyngeal carcinoma
Authors: Xu Y-D , Ou Y-K , Zheng Y-Q , Zhang S-Y
Published: February 2008

Objective:

To investigate methods of treating diffuse osteoradionecrosis of the temporal bone in cases of nasopharyngeal carcinoma, following radiotherapy.

Study design:

Retrospective.

Methods:

Fourteen post-irradiation nasopharyngeal carcinoma patients (n = 14 ears) with diffuse osteoradionecrosis received surgical treatment from March 1994 to May 2005. The patients underwent radical mastoidectomy (five ears), extensive radical mastoidectomy (one ear), or radical mastoidectomy and obliteration with local vascularised fascia flaps (eight ears).

Results:

Six ears fully recovered; two ears were still infectious but sequestrum had not re-formed; five ears (50 per cent) still had repeated suppuration and did not epithelialise; and one ear had local re-formation of sequestrum requiring periodic dressing changes.

Conclusion:

Diffuse osteoradionecrosis of the temporal bone following radiotherapy for nasopharyngeal carcinoma is difficult to treat surgically. The main objective of surgery is to facilitate drainage and to prevent complications. Radical mastoidectomy and obliteration with local vascularised flaps is an effective method.
Phenylthiocarbamide taste perception and susceptibility to motion sickness: linking higher susceptibility with higher phenylthiocarbamide taste acuity
Authors: Sharma K , Sharma P , Sharma A , Singh G
Published: February 2008

Objective:

This study is the first attempt to link quantified phenylthiocarbamide bitter taste recognition threshold with susceptibility to motion sickness.

Subjects:

The study was conducted on a sample of 291 teenage Rajput children (146 males and 145 females; age range 13–19 years) from the Sirmour district of Himachal Pradesh, India. Phenylthiocarbamide taste sensitivity was measured by administering a serial dilution of a freshly prepared phenylthiocarbamide solution, following the method of Harris and Kalmus. Motion sickness susceptibility was assessed retrospectively via interview.

Results:

About 40 per cent of the subjects had experienced motion sickness in the past. The mean and standard deviation of phenylthiocarbamide taste thresholds in non-tasters and tasters were 0.83 ± 0.87 and 7.98 ± 1.86, respectively. A bimodal distribution test (D/S) index of 5.24 confirmed bimodality of phenylthiocarbamide taste threshold distribution. The Mann–Whitney U test rejected the null hypothesis of μ1 = μ2 and thus confirmed the existence of differences in the distributions of phenylthiocarbamide taste threshold between individuals susceptible and not susceptible to motion sickness. Individuals susceptible to motion sickness had lower mean and median taste thresholds, indicating higher phenylthiocarbamide taste sensitivity, compared with non-susceptible individuals. The frequency of non-tasters was about 10 per cent in both motion sickness susceptible and non-susceptible individuals. The simple division of phenylthiocarbamide tasting ability into tasters and non-tasters was a less sensitive criterion with which to measure the association of this ability with motion sickness susceptibility. However, further differentiation of tasters into weak threshold, medium threshold and super threshold (‘supersensitive’) tasters clearly revealed a highly significantly increased risk of motion sickness in super threshold tasters (i.e. threshold solution number ≥12). The ratio of motion sickness susceptible individuals to non-susceptible individuals was 1:1.7 for non-tasters (threshold solution numbers zero to three) and weak and medium tasters (threshold solution numbers four to 11), but the trend was reversed for super threshold tasters (threshold solution numbers 12 and 13), in whom the ratio was 2:1.

Conclusion:

Individuals exhibiting greater phenylthiocarbamide taste acuity (i.e. supersensitive tasters) had a higher susceptibility to motion sickness than did non-, weak and medium phenylthiocarbamide tasters, as measured in terms of their taste thresholds (i.e. threshold solution numbers zero to 11).
Does tonsillectomy lead to improved outcomes over and above the effect of time? A longitudinal study
Authors: Fox R , Temple M , Owens D , Short A , Tomkinson A
Published: February 2008

Objective:

To determine the effect of tonsillectomy on morbidity in patients listed for tonsillectomy.

Design:

Questionnaire survey of 257 children and 159 adults who had been listed for tonsillectomy. The cohort studied had experienced delays of greater than 12 months between being listed for tonsillectomy and undergoing surgery. They had responded to an earlier questionnaire in 2003 regarding morbidity experienced while waiting for surgery. The same questionnaire was presented to them again in 2005. Morbidity experienced in 2003 was compared to that experienced in 2005 in subjects who had and had not proceeded to surgery in the interval.

Results:

Forty-seven per cent of the cohort had undergone tonsillectomy. The questionnaire response rate was 48 per cent. Respondents reported less morbidity in 2005 than in 2003, whether or not they had had surgery. Respondents who had undergone tonsillectomy reported significantly greater reductions in morbidity than those who had not. Five per cent of children who had undergone tonsillectomy experienced at least three short episodes of tonsillitis in the six months before the questionnaire, compared with 35 per cent of those who had not undergone tonsillectomy (p < 0.001).

Conclusions:

The morbidity reported by patients suffering from chronic, untreated tonsillitis decreases with time. Tonsillectomy produces significantly greater reductions in morbidity than time alone.
An unusual succinate dehydrogenase gene mutation C in a case of laryngeal paraganglioma
Authors: Garrel R , Raynaud P , Raingeard I , Muyshondt C , Gardiner Q , Guerrier B , Pujol P , Coupier I
Published: February 2008

Objective:

To report a rare case of a laryngeal paraganglioma related to succinate dehydrogenase gene mutation C.

Method:

A case report and a review of the world literature concerning succinate dehydrogenase mutations and laryngeal paraganglioma are presented.

Results:

We identified a laryngeal paraganglioma in a 38-year-old woman, related to a very rare, deleterious in exon 4 of the succinate dehydrogenase mutation C. This mutation was a non-sense mutation: c.183G >A leading to p.Trp61X. No other neuroendocrine tumour was identified in this case, but a thyroid papillary carcinoma was concomitantly discovered and cured.

Conclusion:

To our knowledge, this is the first report in the world literature of laryngeal paraganglioma related to a succinate dehydrogenase mutation C. The case presented underlines the fact that every patient with paraganglioma should be tested for succinate dehydrogenase genetic mutations, even if a family history of paraganglioma is absent, in order to enable appropriate clinical management and to improve our knowledge of familial paraganglioma.
Long-term effectiveness of antiseptic cream for recurrent epistaxis in childhood: five-year follow up of a randomised, controlled trial
Authors: Robertson S , Kubba H
Published: February 2008

Objectives:

To determine the long-term outcome for children treated for recurrent epistaxis, and to compare the efficacy of antiseptic cream treatment and nasal cautery.

Study design and participants:

Retrospective analytical cohort study of 88 children treated for recurrent epistaxis in 2001.

Methods:

Five-year data on chlorhexidine–neomycin cream usage, nasal cautery, current epistaxis frequency and emergency room attendance was collected by telephone interview and case record review.

Results:

During their first clinic visit, 51 per cent of the children had been treated with cautery and cream and 35 per cent with cream alone; 14 per cent had received no treatment. Five years later, 65 per cent of these children were still having ongoing epistaxis. Those who had undergone cautery and received cream had the highest ongoing bleeding rate (77 per cent).

Conclusion:

The majority of children treated at our clinic for recurrent epistaxis had ongoing bleeding five years later. Despite the proven short-term efficacy of chlorhexidine–neomycin cream, few patients receive further courses of cream or are referred back to the clinic.
I-STOD: a new standardization method for analysing indirect-ELISA results of a schistosomiasis field study
Authors: LUO J. , XU J. , ZHANG Y. , SHAN H. , ZHANG S. , ZHANG M. , TU X. , JI M. , CHEN F. , KNOPF P. M. , KURTIS J. , WU G. , WU H.-W.
Published: February 2008

Variability among samples analysed using the same ELISA protocol generates ambiguity in deciding which assay best quantifies the protein concentration. In this study, we propose a standardization method, called I-STOD (Improved STandardization method for Optical Density), for the transformation of OD values on different plates into relative concentrations of the antibody levels being assessed. We derived an equation relating OD values of different test samples to antibody levels according to the multi-stage reaction dynamics of the indirect-ELISA. Using serum samples from aSchistosomiasis japonicaendemic area, we evaluated the fitness of the I-STOD model to experimental data of a standard reference serum in comparison with 5 other models. Calibration curves fitted by the I-STOD method judged to be superior, based on adjustedR2(adjustedR2>0·99 on 22 out of 26 plates) values. The CV (coefficient of variation) value of the results between multi-well plates and the number of plates with OD values beyond the control range in Shewhart charts also demonstrate that the I-STOD method is a powerful tool which can greatly improve the comparability of results on different multi-well ELISA plates. We conclude that a standardization method is certainly necessary for antibody levels detected in order to properly illustrate clinical differences.
First report of Echinococcus granulosus G8 in Eurasia and a reappraisal of the phylogenetic relationships of ‘genotypes’ G5-G10
Authors: MOKS E. , JÕGISALU I. , VALDMANN H. , SAARMA U.
Published: February 2008

In this study, we investigated the presence of the larval stage of the tapeworm Echinococcus granulosus in wild ungulates in Estonia, genetically characterized E. granulosus isolates using mitochondrial gene sequences and used the sequence data, together with those available in a public database, to infer the phylogenic relationships of E. granulosus ‘genotypes’ G5-G10. While 0·8% of the 2038 moose (Alces alces) examined were found to be infected with E. granulosus, the parasite was not detected in other wild ungulates, such as roe deer (Capreolus capreolus: 1044 specimens examined) and wild boar (Sus scrofa: 442 specimens). Genetic analyses of concatenated atp6, nad1 and cox1 gene (1028 bp) sequences revealed that 2 novel E. granulosus haplotypes, namely E8 (11 samples: 69%) and E10 (5 samples: 31%), grouped with E. granulosus G8 and G10, respectively, are present in Estonia. This is the first record of an E. granulosus G8 in Eurasia. Phylogenetic analyses, using 4 different methods, demonstrated with considerable statistical support that E. granulosus G6/7 forms a subgroup together with G10, whereas G8 is a sister taxon to G6/7-G10.
Outdoor environments for people with dementia: an exploratory study using virtual reality
Authors: BLACKMAN TIM , VAN SCHAIK PAUL , MARTYR ANTHONY
Published: February 2008

Few studies have investigated how outdoor environments might disable people with dementia. The issue is rarely considered in planning and design guidelines and not at all in regulations, despite dementia being within the scope of disability discrimination legislation in the United Kingdom and other countries. This article reports a study that involved older people with mild to moderate dementias taking two walks, one in a real town centre and one in a virtual reality (VR) simulation. Adaptations were made to the VR simulation to test possible design improvements. Overall, the town centre posed relatively few problems for the 38 older people with dementia who participated, although more difficulty was evident with greater impairment. Some features of particular places were liked more than others, particularly the segregation of spaces from motor traffic. There were measurable benefits from using clear textual signs to support wayfinding and to identify objects and places in the environment. Diminished outdoor activity is likely to be experienced as a decrease in quality of life and may accelerate the progression of dementia. We conclude that older people with mild to moderate dementia should be encouraged to be active outdoors and that this can be facilitated by small environmental modifications. Some limitations of the VR technology used for the study are also reported.
Western retirees in Thailand: motives, experiences, wellbeing, assimilation and future needs
Authors: HOWARD ROBERT W.
Published: February 2008

Westerners increasingly retire outside their home countries, and some venture to developing nations. A growing number go to Thailand, usually after working there or after many tourist visits. The present study examined currently and formerly resident Western retirees in Thailand, with a focus on their reasons for migrating to Thailand, their wellbeing and perceived assimilation, the reasons why some leave, and their long-term welfare needs. The principal data source was an online survey of 152 current and former retirees in Thailand. The major reported motives were low living costs, a warm climate, to escape a disliked home nation, like of the Thai lifestyle and culture, and the availability of attractive sexual partners. Most survey respondents had a Thai spouse or live-in partner. The move apparently works out well for most, at least initially. They report positive wellbeing and feel assimilated, but most live with visa insecurity and their assimilation may be partly illusory, as many reported socialising mainly with other foreigners. The major long-term concerns of Western retired men in Thailand are their health-care and welfare needs, income problems, increasing negative local reactions to the influx of Westerners, and the possibility of visa cancellation that would enforce a move elsewhere.
Working beyond the state pension age in the United Kingdom: the role of working time flexibility and the effects on the home
Authors: CEBULLA ANDREAS , BUTT SARAH , LYON NICK
Published: February 2008

The present and future security of employee-pension funding remains at the forefront of public debate across Europe and beyond. In the United Kingdom, to finance future pension entitlements it has been suggested that the state pension age be increased. This paper presents the results of analyses of four major national social surveys that have explored the working and living conditions of workers in paid employment after the state pension age. Comparing the circumstances of these workers with workers just below that age illustrates the extent to which it constitutes a break in the working and domestic lives of older people. The findings suggest that, in order to accommodate older workers in the workplace, more attention may need to be placed on informal as well as contractual arrangements of flexible working. Beyond part-time working, older workers rarely take up additional or alternative flexible working arrangements. At the same time, older workers continue to experience housework as burdensome, while in partnered households the gendered division of domestic labour prevails. Research and policy have yet to consider in depth these risks associated with working longer in life.
It's a family affair: consumer advocacy for nursing-home residents in the United States
Authors: PHILLIPS CHARLES D. , KIMBELL ANNE-MARIE , HAWES CATHERINE , WELLS JANET , BADALAMENTI JEAN , KOREN MARY JANE
Published: February 2008

Nursing homes in the United States have for over 40-years been riddled with evidence of poor performance. To combat problems in this industry, state and federal governments developed an elaborate monitoring and regulatory structure. At the same time, an important citizens' movement involving nursing-home consumer advocacy groups (CAGs) came to life. This paper presents the results of a postal survey of 47 active nursing-home consumer advocacy groups. They indicate that the majority of these organisations were started by an individual dissatisfied with the care provided to a family member. The political arena in which these organisations were most active was State legislatures. Though they varied considerably, the average CAG operated on a thin financial margin, largely supported by member contributions and donations. These organisations defined their success in terms of their ability to generate policy changes at the State level. Unfortunately, as they pursued these changes, they often failed to develop the organisational infrastructure necessary to assure the CAGs' continued operation. When CAGs ceased operations, it was in most cases the loss of the organisation's original leader or the cumulative effects of the constant struggle to maintain adequate financial resources.
Profiles of social relations among older adults: a cross-cultural approach
Authors: FIORI KATHERINE L. , ANTONUCCI TONI C. , AKIYAMA HIROKO
Published: February 2008

This study extends previous research on the profiles of social relations in three ways: (1) by including both functional and qualitative characteristics of social relations; (2) by examining the association of these profiles with mental and physical health and mortality; and (3) by exploring these profiles and associations in two cultures. Using samples of approximately 500 adults aged 60 or more years from theSocial Relations and Mental Health over the Life Coursestudies in both the United States and Japan, separate cluster analyses were conducted for each country. The common or shared network types were labelled ‘diverse’, ‘restricted’, ‘friend-focused’ and ‘family-focused’, but in the US we found two types of ‘friend-focused’ networks (supported and unsupported) and two types of ‘restricted’ networks (structurally- and functionally-restricted). In addition, we found a unique network type in Japan: ‘married and distal’. Multivariate analyses of variance and Cox regressions revealed that whereas individuals in the functionally restricted network type had the worse physical and mental health in the US, Americans in the structurally-restricted network type had the lowest survival rates at a 12-year follow-up. Interestingly, there were no wellbeing differences by network type in Japan. The findings have been interpreted in the light of social relations theories, with special emphasis on the importance of taking a multidimensional perspective and exploring cultural variation.
Social mobility, geographical proximity and intergenerational family contact in Sweden
Authors: FORS STEFAN , LENNARTSSON CARIN
Published: February 2008

This study examined intergenerational family contact. Three questions were considered: Is there a relationship between parent's class, child's class and family contact? Can class-related differences in family contact be explained by differences in geographical distance between parent and child? Is intergenerational family contact affected by children's social mobility? The questions were explored using data from a nationally-representative level of living survey. The results from logistic regressions showed that parent's class as well as the child's class were associated with intergenerational geographical distance and family contact more often than once a week. Those in or retired from non-manual occupations were less likely than manual workers to live close and to have family contact more than once a week. We found no evidence that a change in class position, upward nor downward, had any effect on family contacts. Rather, class-stable non-manual families socialise less frequently than other families, even when they live relatively close. The results therefore suggest that familial class-cohesiveness is a stronger determinant of inter-generational family contacts than social mobility. Future research should address the complex connection between social mobility and other forms of relations and transfers between generations.
Science and imagery in the ‘war on old age’
Authors: VINCENT JOHN A.
Published: February 2008

Several professional groups present themselves as ‘waging war’ on old age. They construct old age as a naturalised, self-evidently negative, biological phenomenon, which must be attacked and defeated. These groups make different claims to technical expertise and their ability to control natural phenomena, and use different weapons to defeat ageing. There are those who focus on cosmetic interventions, that is, the control of the body and the removal or masking of the signs of ageing. There are those who equate old age with ill-health and identify themselves as warriors in a battle with disease, and others whose objective is to understand the fundamental intra-cellular processes of ageing and what controls the human life span, and then to extend its limits. A fourth group aims to make human immortality possible. Examination of the language and symbolic practices of these groups reveals that they share a dominant cultural view that devalues old age and older people. The use of military metaphors to describe the importance and difficulties of their task is most prolific among the first and fourth of these groups. The second and third groups disguise a contradiction in their aim of understanding the diseases and disorders of old age by advocating the goal of an extended ‘healthy life span’, which avoids having to confront the moral dilemmas of extending the lifespan for its own sake.
Algebraic and Heegaard–Floer invariants of knots with slice Bing doubles
Authors: CHA JAE CHOON , LIVINGSTON CHARLES , RUBERMAN DANIEL
Published: February 2008

If the Bing double of a knotKis slice, thenKis algebraically slice. In addition the Heegaard–Floer concordance invariants τ, developed by Ozsváth–Szabó, and δ, developed by Manolescu and Owens, vanish onK.
Jordan homomorphisms revisited
Authors: BREŠAR MATEJ
Published: February 2008

Let θ be a Jordan homomorphism from an algebraAinto an algebraB. We find various conditions under which the restriction of θ to the commutator ideal ofAis the sum of a homomorphism and an antihomomorphism. Algebraic results, obtained in the first part of the paper, are applied to the second part dealing with the case whereAandBareC*-algebras.
On the minimal dimension of a homology sphere on which a finite group acts
Authors: ZIMMERMANN BRUNO P.
Published: February 2008

We show that the minimal dimension of a faithful action of a metacyclic group$\Z_p \rtimes \Z_q$, for primespandq, on a homology sphere coincides with the minimal dimension of a faithful linear action on a sphere; as a consequence, we obtain the analogous result for various finite simple groups.
Inundation of freshwater peatlands by sea level rise: Uncertainty and potential carbon cycle feedbacks
Authors: Henman Jenny , Poulter Benjamin
Published: February 2008

Freshwater peatlands represent an important component of global biogeochemistry through their role in carbon sequestration. Threats to carbon storage in freshwater peat include climate‐related increases in rates of oxidation and methanogenesis, increased wildfires, drainage, and dissolved organic carbon export from runoff. This paper discusses the potential impact of sea level rise on carbon fluxes from coastal peatlands, an issue not addressed by previous studies describing threats to peatlands from global climate change. We estimate carbon stocks and potential emissions from a coastal freshwater peatland located in North Carolina, United States. Four scenarios for inundation were modeled using Hadley‐CM3 scenarios (including the effects of collapsed barrier islands) with a lidar‐derived digital elevation model. Monte Carlo analysis was used to address model uncertainty and sensitivity of carbon emission parameters for three scenarios. Total existing carbon storage (peat and vegetation) on the Peninsula (5671 km2) was estimated to range between 155.5 and 201.0 TgC (95% confidence intervals). Sea level projections ranged from 0.35 to 1.38 m by the end of the century and were estimated to inundate between 1260 and 3020 km2 of the Peninsula. Carbon emissions from inundation of peat and vegetation ranged from 4.7–20.9 TgC (assuming inundation preserved peat deposits) to 99.4–128.0 TgC (assuming 100% emissions of inundated peat). While considerable uncertainty exists regarding the fate of carbon fluxes, we identify 150,000 km2 of freshwater peatlands worldwide below 5‐m elevation and vulnerable to sea level rise. Our study suggests that future sea level rise may contribute a positive feedback to the global carbon cycle.
Combustion iron distribution and deposition
Authors: Luo Chao , Mahowald N. , Bond T. , Chuang P. Y. , Artaxo P. , Siefert R. , Chen Y. , Schauer J.
Published: February 2008

Iron is hypothesized to be an important micronutrient for ocean biota, thus modulating carbon dioxide uptake by the ocean biological pump. Studies have assumed that atmospheric deposition of iron to the open ocean is predominantly from mineral aerosols. For the first time we model the source, transport, and deposition of iron from combustion sources. Iron is produced in small quantities during fossil fuel burning, incinerator use, and biomass burning. The sources of combustion iron are concentrated in the industrialized regions and biomass burning regions, largely in the tropics. Model results suggest that combustion iron can represent up to 50% of the total iron deposited, but over open ocean regions it is usually less than 5% of the total iron, with the highest values (<30%) close to the East Asian continent in the North Pacific. For ocean biogeochemistry the bioavailability of the iron is important, and this is often estimated by the fraction which is soluble (Fe(II)). Previous studies have argued that atmospheric processing of the relatively insoluble Fe(III) occurs to make it more soluble (Fe(II)). Modeled estimates of soluble iron amounts based solely on atmospheric processing as simulated here cannot match the variability in daily averaged in situ concentration measurements in Korea, which is located close to both combustion and dust sources. The best match to the observations is that there are substantial direct emissions of soluble iron from combustion processes. If we assume observed soluble Fe/black carbon ratios in Korea are representative of the whole globe, we obtain the result that deposition of soluble iron from combustion contributes 20–100% of the soluble iron deposition over many ocean regions. This implies that more work should be done refining the emissions and deposition of combustion sources of soluble iron globally.
Characteristics of ambient seismic noise as a source for surface wave tomography
Authors: Yang Yingjie , Ritzwoller Michael H.
Published: February 2008

Interstation cross correlations of ambient seismic noise from 1 year of continuous data at periods between 6 and 50 s are used to study the origin of the ambient noise using stations located in Europe, southern Africa, Asia, and three regions within North America. The signal‐to‐noise ratios (SNR) of Rayleigh waves for positive and negative correlation time lags at periods of 8, 14, 25 and 50 s are used to determine the azimuthal distribution of strong ambient noise sources. Ambient noise in both the primary (10–20 s) and secondary microseism bands (5–10 s) comes dominantly from the directions of relatively nearby coastlines with stronger noise occurring in the Northern Hemisphere in northern winter and in the Southern Hemisphere in southern winter, consistent with the hypothesis that oceanic microseisms are generating this noise. The observed differences in the directivity of noise in the primary and secondary microseism bands are the consequence of propagation and attenuation, rather than the location of generation. At intermediate and long periods (>20 s), there is much less seasonal variation in both signal strength and directivity. We argue that our results are explained most simply by near‐coastal sources rather than deep ocean sources at all periods. Although the dominant ambient noise sources are distributed inhomogeneously in azimuth, strong ambient noise emerges from most directions when using recordings that are 1 year in duration. Simulations illustrate that this is what ensures the accuracy of the empirical Green's functions and ambient noise tomography.
Solar modulation of the Northern Hemisphere winter trends and its implications with increasing CO2
Authors: Kodera Kunihiko , Hori Masatake E. , Yukimoto Seiji , Sigmond Michael
Published: February 2008

The origin of the recent trends in the Northern Hemisphere (NH) winter circulation is investigated. Linear trends are calculated separately for low solar (LS) and high solar (HS) winters. Trends during HS exhibit a North Atlantic Oscillation (NAO)/Arctic Oscillation (AO)‐like pattern that is related to a stronger stratospheric polar vortex. Whereas during LS, decreasing trends of sea‐level pressure appear over the northeastern Pacific in association with warming trends in the tropical troposphere which lead to a strengthening of the subtropical jet and a weakening of the polar night jet. These two trends compare well with those found in previous numerical model simulations where the CO2 was doubled in either the troposphere or the middle atmosphere. This suggests that the stratospheric cooling effect due to increased CO2 manifests in the troposphere through nonlinear interaction with solar cycle.
Tidal variability in the lower thermosphere: Comparison of Whole Atmosphere Model (WAM) simulations with observations from TIMED
Authors: Akmaev R. A. , Fuller‐Rowell T. J. , Wu F. , Forbes J. M. , Zhang X. , Anghel A. F. , Iredell M. D. , Moorthi S. , Juang H.‐M.
Published: February 2008

The upper atmosphere and ionosphere exhibit variability on spatial and temporal scales characteristic of tides and planetary waves originating in the lower atmosphere. To study their generation, vertical propagation, possible nonlinear interactions and effects a new Whole Atmosphere Model (WAM) has been developed as part of the Integrated Dynamics through Earth's Atmosphere (IDEA) project. WAM is a 150‐layer general circulation model based on the US National Weather Service's operational Global Forecast System (GFS) model extended upward to cover the atmosphere from the ground to about 600 km. First simulations reveal the presence of migrating and nonmigrating tides modulated at planetary wave periods in the upper atmosphere. Comparisons with observations from the TIMED satellite in the lower thermosphere show that WAM reproduces the seasonal variability of tides remarkably well, including the diurnal eastward harmonic with zonal wavenumber 3 (DE3) recently implicated in the observed spatial morphology of the ionosphere.
Net changes in aboveground woody carbon stock in western juniper woodlands, 1946–1998
Authors: Strand Eva K. , Vierling Lee A. , Smith Alistair M. S. , Bunting Stephen C.
Published: February 2008

Although regional increases in woody plant cover in semiarid ecosystems have been identified as a worldwide phenomenon affecting the global carbon budget, quantifying the impact of these vegetation shifts on C pools and fluxes is challenging. Challenges arise because woody encroachment is governed by ecological processes that occur at fine spatial resolutions (1–10 m) and, in many cases, at slow (decadal‐scale) temporal rates over large areas. We therefore analyzed time series aerial photography, which exhibits both the necessary spatial precision and temporal extent, to quantify the expansion of western juniper into sagebrush steppe landscapes in southwestern Idaho. We established upper and lower bounds of aboveground woody carbon change across the landscape via two‐dimensional spatial wavelet analysis, image texture analysis, and field data collection. Forty‐eight 100‐ha blocks across a 330,000‐ha region were stratified by topography, soil characteristics, and land stewardship for analyses. Across the area we estimate aboveground woody carbon accumulation rates of 3.3 gCm−2yr−1 and 10.0 gCm−2yr−1 using the wavelet and texture method, respectively, during the time period 1946–1998. Carbon accumulation rates were significantly affected by soil properties and were highly dependent on the spatial and temporal scales of analysis. For example, at a 100‐ha scale the aboveground carbon accumulation varied from −1.7 to 9.9 gCm−2yr−1, while at the 1‐ha scale the range of variability increased to −11 to 22 gCm−2yr−1. These values are an order of magnitude lower than those previously suggested due to woody encroachment, highlighting the need for examining multiple spatial scales when accounting for changes in terrestrial carbon storage.
Dipyridamole enhances ischaemia‐induced reactive hyperaemia by increased adenosine receptor stimulation
Authors: Meijer P , Wouters C W , van den Broek P H H , Scheffer G J , Riksen N P , Smits P , Rongen G A
Published: February 2008

Background and purpose:

Dipyridamole enhances post‐occlusive reactive hyperaemia (PORH) in the human forearm vascular bed. We hypothesize that this effect is completely mediated by increased adenosine receptor stimulation. To test this hypothesis, the effect of caffeine (an adenosine receptor antagonist) on dipyridamole‐induced augmentation of PORH was explored.

Experimental approach:

The forearm vasodilator responses to three increasing periods of forearm ischaemia (2, 5 and 13 min) were determined during placebo infusion. Forty minutes after the last reperfusion period, this procedure was repeated during intra‐arterial infusion of dipyridamole (7.4 nmol min−1 per 100 ml forearm). At least 2 weeks later, this whole procedure was repeated, but now in the presence of caffeine (90 μg min−1 per 100 ml volume).

Key results:

After 2, 5 and 13 min of ischaemia, the average forearm blood flow increased to 5.6±0.7, 9.7±1.3 and 34.5±2.1 ml min−1 per 100 ml. After infusion of dipyridamole into the brachial artery, these numbers were significantly increased to 7.7±0.8, 12.5±1.5 and 41.6±3.1 ml min−1 per 100 ml. This response was abolished by the concomitant infusion of caffeine (6.6±0.5, 10.2±0.6, 35.1±2.2 (caffeine) versus 7.4±0.4, 10.5±0.6, 33.7±2.2 ml min−1per 100 ml (caffeine/dipyridamole)).

Conclusions and implications:

Caffeine prevented the augmenting effect of dipyridamole on PORH. This indicates that dipyridamole‐induced augmentation of PORH is mediated via increased adenosine receptor stimulation as a result of elevated extracellular formation of adenosine during ischaemia.

British Journal of Pharmacology (2008) 153, 1169–1176; doi:10.1038/bjp.2008.10; published online 11 February 2008
Evidence for the participation of calcium in non‐genomic relaxations induced by androgenic steroids in rat vas deferens
Authors: Lafayette S S L , Vladimirova I , Garcez‐do‐Carmo L , Monteforte P T , Caricati Neto A , Jurkiewicz A
Published: February 2008

Background and purpose:

Androgens cause non‐genomic relaxation in several smooth muscle preparations. However, such an effect has not been investigated in rat vas deferens yet. Our purpose was to study the effect of testosterone and derivatives in this tissue.

Experimental approach:

The influence of androgens was tested on contraction and translocation of intracellular Ca2+ induced by KCl in rat vas deferens in vitro.

Key results:

The testosterone derivative 5α‐dihydrotestosterone produced a rapid and reversible concentration‐dependent relaxation of KCl‐induced contractions. Other androgens were also effective, showing the following rank order of potency: androsterone >5β‐dihydrotestosterone >androstenedione >5α‐dihydrotestosterone >testosterone. Calcium‐induced contractions were also inhibited (about 45%) by 5α‐dihydrotestosterone (30 μM). Moreover 5α‐dihydrotestosterone blocked the increase of intracellular Ca2+ induced by KCl, measured by the fluorescent dye fura‐2. Relaxation to 5α‐dihydrotestosterone was resistant to the K+ channel antagonists glibenclamide, 4‐aminopyridine and charybdotoxin. It was not affected by removal of epithelium or by L‐NNA (300 μM), an inhibitor of nitric oxide biosynthesis, nor by selective inhibitors of soluble guanylate cyclase, ODQ or LY 83583, indicating that nitrergic or cGMP mediated mechanisms were not involved. The androgen‐induced relaxation was also not blocked by the protein synthesis inhibitor cycloheximide (300 μM) or by the classical androgen receptor flutamide (up to 100 μM), corroborating that the effect is non‐genomic.

Conclusions and implications:

Testosterone derivatives caused relaxation of the rat vas deferens, that did not involve epithelial tissue, K+ channels, or nitric oxide‐dependent mechanisms, but was related to a partial blockade of Ca2+ influx.

British Journal of Pharmacology (2008) 153, 1242–1250; doi:10.1038/bjp.2008.18; published online 11 February 2008
Rhein reverses the diabetic phenotype of mesangial cells over‐expressing the glucose transporter (GLUT1) by inhibiting the hexosamine pathway
Authors: Zheng J‐M , Zhu J‐M , Li L‐S , Liu Z‐H
Published: February 2008

Background and purpose: Rhein, an anthraquinone compound isolated from rhubarb, has been proved effective in treatment of experimental diabetic nephropathy (DN). To explore the mechanism of its therapeutic effect on DN, rhein was tested for its effect on the hexosamine pathway.

Experimental approach: The influence of rhein on cellular hypertrophy, fibronectin synthesis, glucose uptake, glutamine: fructose 6‐phosphate aminotransferase (GFAT) activity, UDP‐N‐acetylglucosamine (UDP‐GlcNAc) level and TGF‐β1 and p21 expression was evaluated in MCGT1 cells, a GLUT1 transgenic rat mesangial cell line. GFAT activity in normal rat mesangial cells in high glucose concentrations and in vitro was also measured.

Key results: Significantly increased fibronectin synthesis, cellular hypertrophy, much higher GFAT activity and UDP‐GlcNAc level and increased TGF‐β1 and p21 expression were found in MCGT1 cells cultured in normal glucose concentration. Rhein treatment decreased all these features of MCGT1 cells but did not exert a direct effect on GFAT enzymatic activity.

Conclusions and implications: There was over‐activity of the hexosamine pathway in MCGT1 cells, which may explain the higher expression of TGF‐β1 and p21, the cellular hypertrophy and the increased expression of extracellular matrix (ECM) components in the cells. By inhibiting the increased activity the hexosamine pathway, rhein decreased TGF‐β1 and p21 expression and thus contributed to the decreased cellular hypertrophy and ECM synthesis. Inhibition of the hexosamine pathway may be one of the mechanism through which rhein exerts its therapeutic role in diabetic nephropathy.

British Journal of Pharmacology (2008) 153, 1456–1464; doi:10.1038/bjp.2008.26; published online 11 February 2008