bluuebunny/crossref_metadata_2025 huggingface dataset:
Nasal nitric oxide measurements before and after repeated humming maneuvers
Authors: Maniscalco M. , Sofia M. , Weitzberg E. , Carratu L. , Lundberg J. O. N.
Published: November 2003

Background  It has been recently shown that humming greatly increases nasal nitric oxide (NO). This is most likely owing to a rapid washout of sinus NO caused by the oscillating sound waves. During repeated humming manoeuvres nasal NO gradually decreases, likely because NO accumulated in the sinuses is washed out.

Aim  We studied whether humming before measurements would affect nasally exhaled NO.

Materials and methods  NO output was measured by the chemiluminescence technique in orally and nasally exhaled air in 38 subjects: 18 healthy subjects (HS), 15 subjects with allergic rhinitis (AR) and five subjects with allergic nasal polyposis (AP). Each subject performed a NO measurement during quiet nasal exhalation either preceded by a period of silence/free speaking or immediately after five consecutive humming manoeuvres (posthumming).

Results  Mean nasal NO output (95% CI) after a period of silence/free speaking was 231 nL min−1 (178–284) in HS, 434 nL min−1 (347–522) in AR (P < 0·001) and 262 nL min−1 (163–361) in AP. Post‐humming nasal NO output was 16% (5 to 50%) lower in HS and 14% (1 to 49%) lower in AR, while it remained unchanged in AP subjects. Intra‐subject coefficient of variation of quiet nasal exhalation was 12% in HS, 13% in AR and 5% in AP. Post humming intraindividual coefficient of variation significantly decreased in both HS and AR, but it did not change in AP.

Conclusions  Nasal NO levels measured immediately after repeated humming manoeuvres are consistently lower and more reproducible than nasal NO levels measured after a period of silence or free speaking. Repeated humming effectively empties the sinuses, thereby probably minimizing the normal contribution from the sinuses to nasal NO. This may be useful to better estimate NO output from the nasal cavity mucosa in health and disease.
Gender, age and menopause effects on the prevalence and the characteristics of obstructive sleep apnea in obesity
Authors: Resta O. , Caratozzolo G. , Pannacciulli N. , Stefàno A. , Giliberti T. , Carpagnano G. E. , De Pergola G.
Published: November 2003

Background  In the 1970s and 80s it was believed that obstructive sleep apnea (OSA) was primarily a disease of men. The present study was addressed to evaluate the effect of gender and menopause on the prevalence and the characteristics of OSA and on anthropometric, clinical, respiratory and polysomnographic data in a population of obese individuals.

Patients and methods  A total of 230 obese subjects (BMI ≥ 30 kg m−2), 148 women and 82 men, aged 16–75 years, were recruited and evaluated for general and anthropometric parameters, respiratory function, sleep‐related symptoms and sleep disorders of breathing.

Results  Respiratory disturbance index (RDI) and the prevalence of OSA were lower in women than in men (P < 0·001 and P < 0·001, respectively). Among subjects < 55 years, neck circumference, percentage of predicted normal neck circumference (PPNC), waist‐to‐hip ratio (WHR), PaCO2, RDI and the prevalence of OSA were lower in female subjects (P = 0·05, P < 0·05, P < 0·001, P < 0·01 and P < 0·01, respectively). BMI, neck circumference, PPNC, WHR, RDI and the prevalence of OSA were higher in postmenopausal compared with premenopausal women (P < 0·01, P < 0·01, P < 0·01, P < 0·01 and P < 0·01, respectively).

Conclusions  Our study demonstrates that (i) the male dominance regarding the prevalence and the severity of OSA disappears in men older than 55 years, and (ii) menopause seems to play a pivotal role in modulating both the presence and the degree of sleep disorder.
Biocompatibility of resin‐based materials used as pulp‐capping agents
Authors: Costa C. A. S. , Oliveira M. F. , Giro E. M. A. , Hebling J.
Published: November 2003

Aim  To evaluate and compare the response of pulps of rats capped with resin‐modified glass‐ionomer cement (RMGIC) or self‐etching adhesive system.

Methodology  Class I cavities were prepared on the occlusal surface of 54 maxillary first molars of 27 rats. Pulp exposure was performed on the cavity floor. The following resin‐based materials were applied as pulp‐capping agents: G1, Clearfil Liner Bond 2V (CLB 2V; Kuraray Co., Japan); G2, Vitrebond (VIT; 3M/ESPE, USA). In group 3 (control group), a calcium hydroxide/saline paste (CH; Labsynth, Brazil) was used. The cavities were restored with amalgam. After 7, 30 and 60 days, the animals were sacrificed and the jaws were processed for microscopic evaluation.

Results  Despite the inflammatory response caused by the experimental and the control materials at 7 days, pulpal healing associated with calcified barrier formation was observed at 60 days following the pulp therapy. Both resin‐based materials promoted a large zone of cell‐rich fibrodentine matrix deposition on the pulp horn related to the pulp exposure site, which was larger to VIT than to CLB 2V specimens. Tertiary dentine underneath the fibrodentine matrix was deposited by a layer of elongated pulpal cells. The remaining pulpal tissue exhibited normal histological characteristics. In the control group, healing and dentine‐bridge formation was observed at 30 days. Pulpal breakdown occurred only when bacterial infection occurred.

Conclusion  Both experimental pulp‐capping agents allowed pulpal healing characterized by cell‐rich fibrodentine and tertiary dentine deposition as well as calcified barrier formation.
Focal cemento‐osseous dysplasia involving a mandibular lateral incisor
Authors: Galgano C. , Samson J. , Küffer R. , Lombardi T.
Published: November 2003

Aim  To report a case of focal cemento‐osseous dysplasia (FCOD) affecting a single tooth misdiagnosed as an inflammatory periapical lesion.

Summary  The patient, a black 47‐year‐old woman complained of pain affecting the right side of the mandible. Routine X‐ray examination discovered a periapical radiolucency on the mandibular left lateral incisor (tooth 32), which was otherwise normal and not carious. As the response of this tooth to a vitality test was doubtful, the lesion was diagnosed as a periapical granuloma or cyst secondary to pulpal necrosis. Endodontic treatment and curettage of the periapical lesion were performed, and histological examination of the curettage material revealed a localized osseous dysplasia.

Key learning points 

FCOD may rarely affect only one tooth, resembling a periapical granuloma or cyst.

Careful diagnosis is of paramount importance in cases of questionable periapical lesions affecting normal‐looking teeth, before beginning treatment.

FCOD generally requires no treatment. Biopsy is warranted in case of doubt.
Comparison of MicroSeal and System B/Obtura II obturation techniques
Authors: Cathro P. R. , Love R. M.
Published: November 2003

Aim  To compare the proportion of gutta‐percha, sealer and voids following the filling of simulated root canals in plastic blocks using two warm gutta‐percha techniques.

Methodology  Ten simulated root canals in plastic blocks were prepared using System GT Rotary Files® and a .02 taper size 40 Quantec rotary nickel–titanium instrument and then filled with MicroSeal and Kerr EWT sealer. A further 10 simulated canals were prepared solely with System GT Rotary Files® and obturated with System B/Obtura II and Kerr EWT sealer. All blocks were sectioned at 1 mm intervals. The sectioned root fillings were photographed through a stereomicroscope and the resultant slides scanned. The images were analysed using adobe photoshop 6.0 to give the proportions of gutta‐percha, sealer or void at each level. The data were analysed using unpaired Student's t‐test and Mann–Whitney U‐test.

Results  The MicroSeal technique produced a dense homogeneous gutta‐percha fill at the apical 1 and 2 mm levels similar to the System B/Obtura II technique, but further coronally the sealer became mixed into the MicroFlow gutta‐percha producing a heterogeneous mass with significantly less (P < 0.05) solid gutta‐percha in the root filling compared to System B/Obtura II. The MicroSeal technique generally had more pooling of cement than the System B technique, however, this was only significantly different (P < 0.05) at the 4 mm level. The System B/Obtura II obturation gave an average of 99.27% ± 1.09 gutta‐percha fill at all levels.

Conclusions  The MicroSeal technique produced a heterogeneous fill consisting of the MicroFlow Master Cone and gutta‐percha from the MicroFlow Cartridge mixed with sealer. The System B/Obtura II technique produced a homogeneous fill at all levels.
Do anticoagulants improve survival in patients presenting with venous thromboembolism?
Authors: Kelly J. , Hunt B. J.
Published: November 2003

Anticoagulants have been available since around 1940 and have become the standard of treatment for venous thromboembolism (VTE) for over four decades. However, as with other treatments which became established before the evidence‐based era, there is a paucity of evidence from randomized controlled trials validating their effectiveness in preventing the most feared complication of VTE, recurrent fatal pulmonary embolism (PE). Only two such trials have been performed, the results of which conflict. The bulk of data supporting their use are derived from three sources. First, studies of thromboprophylaxis, and comparisons of shorter and longer courses of anticoagulants in high‐risk patients with established VTE have clearly demonstrated their effectiveness in primary and late secondary prevention. Given that heparin has an immediate onset of action, anticoagulants should therefore also be effective in early secondary prevention, the proposed mechanism of action in the acute treatment of VTE. Secondly, studies of inadequately treated patients have consistently shown higher recurrence rates than in those adequately treated. Finally, comparisons of outcomes in untreated and treated historical series, and of untreated historical series to treated series in the modern era have shown substantially lower rates of fatal PE in anticoagulated patients. Because these differences are so marked, harmonize with our current understanding of the mechanism of action of anticoagulants and are supported by other evidence, it is much more likely that they at least partly reflect the effectiveness of anticoagulants as opposed to being explicable purely in terms of accumulated biases and a changing distribution of disease severity.
A young man with a renal colic
Authors: Barbey F. , Matthieu C. , Nseir G. , Burnier M. , Teta D.
Published: November 2003

We report the case of a 35‐year‐old man with no cardiovascular morbidity, presenting with acute flank pain, microscopic haematuria and normal blood pressure. Initially diagnosed as a ureteral colic, the patient was recovered 6 weeks later with severe hypertensive crisis. Further investigations revealed a massive renal infarction secondary to medial fibromuscular dysplasia (FMD). Several aspects of this presentation are intriguing. Renal infarcts are usually seen in older patients having cardiac problems and/or major atheromatous plaques. In addition, FMD is mainly observed in young females and rarely progresses to renal artery occlusion. Furthermore, in this case, FMD remained silent until the acute renal infarction occurred, despite a significant kidney size reduction at the time of diagnosis. Finally, the observation of a delayed hypertensive response to a major renovascular insult provides incentives to discuss possible pathophysiological mechanisms involved in renovascular hypertension.
Use of α‐blockers and the risk of hip/femur fractures
Authors: Souverein P. C. , Van Staa T. P. , Egberts A. C. G. , De la Rosette J. J. M. C. H. , Cooper C. , Leufkens H. G. M.
Published: November 2003

Objective.  To study the association between use of α‐blockers and risk of hip/femur fractures.

Design.  Population‐based case–control study.

Setting.  General Practice Research Database.

Subjects.  Cases were defined as men, aged 40 years and older with a first diagnosis for hip/femur fracture. Controls were matched 1 : 1 on gender, year of birth and general practitioner‐practice.

Results.  In all, 4571 cases and an equal number of controls were identified. Current use of α‐blockers (prazosin, doxazosin, indoramin, terazosin, alfuzosin and tamsulosin) was compared with non‐use of α‐blockers. Current use of α‐blockers on the index date was associated with an increased risk of hip/femur fracture [adjusted odds ratio (OR) 1.9, 95% confidence interval (CI): 1.1–3.0] in the overall analysis. The effect was particularly strong for first prescriptions within a treatment episode (adjusted OR 5.1, 95% CI: 1.0–31.7) and during the first month of treatment (adjusted OR 4.1, 95% CI: 0.7–23.9). Stratification according to indication of use showed that current use of α‐blockers was not associated with hip/femur fracture in men with a diagnosis of benign prostatic hyperplasia (adjusted OR 1.0, 95% CI: 0.4–2.5), but was associated in men who used α‐blockers for cardiovascular disease (adjusted OR 2.8, 95% CI: 1.4–5.4).

Conclusion.  Current use of α‐blockers was associated with an increased risk of hip/femur fracture and with the start of a new treatment episode. The effect seemed to be confined to patients who used α‐blockers for cardiovascular disease. Caution with respect to first‐dose effects related to the initiation of a new episode of α‐blocker treatment is advised.
Waist circumference, waist–hip ratio and body mass index and their correlation with cardiovascular disease risk factors in Australian adults
Authors: Dalton M. , Cameron A. J. , Zimmet P. Z. , Shaw J. E. , Jolley D. , Dunstan D. W. , Welborn T. A. ,   On behalf of the AusDiab steering committee
Published: November 2003

Objectives.  To compare body mass index (BMI), waist circumference and waist–hip ratio (WHR) as indices of obesity and assess the respective associations with type 2 diabetes, hypertension and dyslipidaemia.

Design and setting.  A national sample of 11 247 Australians aged ≥25 years was examined in 2000 in a cross‐sectional survey.

Main outcome measures.  The examination included a fasting blood sample, standard 2‐h 75‐g oral glucose tolerance test, blood pressure measurements and questionnaires to assess treatment for dyslipidaemia and hypertension. BMI, waist circumference and WHR were measured to assess overweight and obesity.

Results.  The prevalence of obesity amongst Australian adults defined by BMI, waist circumference and WHR was 20.8, 30.5 and 15.8% respectively. The unadjusted odds ratio for the fourth vs. first quartile of each obesity measurement showed that WHR had the strongest relationship with type 2 diabetes, dyslipidaemia (women only) and hypertension. Following adjustment for age, however, there was little difference between the three measures of obesity, with the possible exceptions of hypertension in women, where BMI had a stronger association, and dyslipidaemia in women and type 2 diabetes in men, where WHR was marginally superior.

Conclusions.  Waist circumference, BMI and WHR identified different proportions of the population, as measured by both prevalence of obesity and cardiovascular disease (CVD) risk factors. Whilst WHR had the strongest correlations with CVD risk factors before adjustment for age, the three obesity measures performed similarly after adjustment for age. Given the difficulty of using age‐adjusted associations in the clinical setting, these results suggest that given appropriate cut‐off points, WHR is the most useful measure of obesity to use to identify individuals with CVD risk factors.
Expression of Th1 markers by lung accumulated T cells in pulmonary sarcoidosis
Authors: Katchar K. , Eklund A. , Grunewald J.
Published: November 2003

Objectives.  The balance between Th1 and Th2 T cells, classified by virtue of their cytokine production can in an immune response influence the phenotype and progression of several clinical diseases. In this study, we examined the expression of Th1 associated chemokine and cytokine receptors CXCR3, CCR5, and interleukin (IL)‐12R, IL‐18R, respectively, as well as of the Th2 associated chemokine receptors CCR4 and CXCR4 on CD4+ and CD8+ T cells.

Subjects.  Eighteen patients with untreated pulmonary sarcoidosis.

Materials and methods.  We used monoclonal antibodies and flow cytometry to analyse the expression of chemokine receptors CXCR3, CXCR4, CCR4 CCR5 and cytokine receptors IL‐12R, IL‐18R in combination with anti‐CD4 and anti‐CD8 mAbs in bronchoalveolar lavage fluid (BAL) and peripheral blood lymphocytes (PBL) from sarcoidosis patients.

Results.  There were significantly more BAL CD4+ T cells expressing CXCR3, CCR5, IL‐12R and IL‐18R compared with paired PBL CD4+ T cells. In contrast, the Th2 associated chemokine receptors CXCR4 and CCR4 were expressed by a fewer percentage of BAL CD4+ compared with PBL CD4+ T cells. There was a positive correlation between the percentage of BAL lymphocytes and the number of CXCR3 and CCR5 expressing CD4+ BAL T cells. Also, the number of CD4+ IL‐18R+ BAL fluid cells correlated negatively with disease duration.

Conclusions.  The lung accumulation of CXCR3, CCR5, IL‐12R and IL‐18R expressing T cells is in line with previous reports showing elevated levels in the lung of the corresponding ligands in sarcodosis. Blocking such ligands and/or receptors may develop into a future immunomodulatory therapy.
Fracture risk associated with smoking: a meta‐analysis
Authors: Vestergaard P. , Mosekilde L.
Published: November 2003

Objectives.  To assess fracture risk associated with smoking.

Design.  Systematic review.

Data sources.  Cohort, case–control, and cross‐sectional studies identified by searching PubMed and EMBASE, and by recursive screening of reference lists.

Subjects.  Fifty studies including 512 399 subjects were included.

Main outcome measure.  Fracture occurrence in current, previous, and never smokers.

Results.  Fracture risk was significantly increased in current smokers for all fracture types combined (pooled relative risk 1.26, 95% CI 1.12–1.42) and for hip (1.39, 95% CI 1.23–1.58) and spine fractures (1.76, 95% CI 1.10–2.82), but not for wrist fractures (0.86, 95% CI 0.46–1.60). In previous smokers the estimate was significantly lower for as well all types of fractures (1.02, 95% CI 0.85–1.22, P = 0.03 compared with current smokers), as for hip fractures (1.19, 95% CI 1.06–1.34, P = 0.04). There was a trend towards higher risk estimates in previous smokers for hip fractures in case–control studies than in cohort studies. A similar difference between case–control and cohort studies was not present for current smokers. There was a geographical heterogeneity: the risk of hip fractures associated with current smoking increased with latitude, i.e. the risk was higher in Northern Europe and the USA than in Southern Europe and countries close to the equator.

Conclusions.  Smoking is associated with an increased overall fracture risk, an increased risk of hip and spine but not wrist fractures. Cessation of smoking seems associated with a decrease in fracture risk. The impact of smoking varied geographically with an increase with latitude.
Aspirin in the prevention of progressing stroke: a randomized controlled study
Authors: Rödén‐Jüllig Å. , Britton M. , Malmkvist K. , Leijd B.
Published: November 2003

Objectives.  In acute stroke, progression has a severe impact on patient outcome and no effective treatment is known. The main objective was to evaluate the efficacy of aspirin for prevention of stroke progression thereby improving outcome.

Design.  The trial was randomized, double‐blind and placebo‐controlled.

Setting.  The patients were treated in stroke units of four hospitals in Sweden.

Subjects.  Patients with ischaemic stroke but not complete paresis were included. No antiplatelet drugs were allowed within the last 72 h before onset. Delay until first trial dosage was maximized to 48 h. The trial was designed to detect a 20% reduction of the rate of stroke progression, which was estimated to take place in 20% of cases. Totally, 441 patients (220 aspirin, 221 placebo) completed the trial. Baseline comparisons between the groups showed no differences.

Interventions.  Aspirin (325 mg) or placebo was given once daily for five consecutive days.

Main outcome measures.  Neurological assessments were carried out three times daily during the treatment period to detect progression of at least two points in the Scandinavian Stroke Supervision Scale. Patient outcome was followed up at discharge and at 3 months.

Results.  Aspirin treatment did not significantly reduce the frequency of stroke progression. Amongst aspirin‐treated patients, stroke progression occurred in 15.9% as compared with 16.7% in the placebo group, which is less frequent than expected. The relative risk was 0.95 (95% CI 0.62–1.45) in the treatment group. As regards patient outcome at discharge and after 3 months, aspirin treatment did not show any difference.

Conclusion.  No positive effect of aspirin, of the expected size, could be shown on the frequency of stroke progression or patient outcome.
Blunted increase in plasma adenosine levels following dipyridamole stress in dilated cardiomyopathy patients
Authors: Laghi‐Pasini F. , Guideri F. , Petersen C. , Lazzerini P. E. , Sicari R. , Capecchi P. L. , Picano E.
Published: November 2003

Background.  Heart failure is characterized by chronically increased adenosine levels, which are thought to express a protective anti‐heart failure activation of the adenosinergic system. The aim of the study was to assess whether the activation of adenosinergic system in idiopathic dilated cardiomyopathy (IDC) can be mirrored by a blunted increase in plasma adenosine concentration following dipyridamole stress, which accumulates endogenous adenosine.

Methods.  Two groups were studied: IDC patients (n = 19, seven women, mean age 60 ± 12 years) with angiographically confirmed normal coronary arteries and left ventricular ejection fraction <35%; and normal controls (n = 15, six women, mean age 68 ± 5 years). Plasma adenosine was assessed by high‐performance liquid chromatography methods in blood samples from peripheral vein at baseline and 12 min after dipyridamole infusion (0.84 mg kg−1 in 10 min).

Results.  At baseline, IDC patients showed higher plasma adenosine levels than controls (276 ± 27 nm L−1 vs. 208 ± 48 nm L−1, P < 0.001). Following dipyridamole, IDC patients showed lower plasma adenosine levels than controls (322 ± 56 nm L−1 vs. 732 ± 250 nm L−1, P < 0.001). The dipyridamole‐induced percentage increase in plasma adenosine over baseline was 17% in IDC and 251% in controls (P < 0.001). By individual patient analysis, 18 IDC patients exceeded (over the upper limit) the 95% confidence limits for normal plasma adenosine levels at baseline, and all 19 exceeded (below the lower limit) the 95% confidence limits for postdipyridamole plasma adenosine levels found in normal subjects.

Conclusion.  Patients with IDC have abnormally high baseline adenosine levels and – even more strikingly – blunted plasma adenosine increase following dipyridamole infusion. This is consistent with a chronic activation of the adenosinergic system present in IDC, which can be measured noninvasively in the clinical theatre.
Puberty: A Period of Both Organizational and Activational Effects of Steroid Hormones On Neurobehavioural Development
Authors: Romeo R. D.
Published: November 2003

During perinatal development, steroid hormones act on the central nervous system (CNS) to organize neural circuits. These circuits remain relatively dormant until hormonal stimulation received in adulthood acts on the CNS to activate adult reproductive physiology and behaviour. In this review, the proposal is put forward that, in addition to perinatal development, puberty serves as another period of neural maturation mediated by both steroid‐dependent and ‐independent events that further organize and shape the behavioural potential of the adult organism. In support of this thesis, data are summarized that clearly show the organizational effects of the pubertal rise in gonadal hormones on mating behaviour and other steroid‐mediated behaviours exhibited in adulthood, and on the neural pathways that mediate these behaviours. The importance of determining whether this sensitive period of neural development during puberty is a ‘critical period’ is also discussed, as well as whether perturbations of the nervous system during pubertal development may result in negative behavioural and physiological outcomes in adulthood. It is concluded that puberty is not merely a time when increasing levels of gonadal steroids activate the neural circuits organized during perinatal development, but also a time of further organization of the CNS, which allows for appropriate behaviours to emerge in adulthood.
The Inhibition of Inducible Nitric Oxide Synthase Reverts Arthritic‐Induced Decrease in Pituitary Growth Hormone mRNA But Not in Liver Insulin‐Like Growth Factor I mRNA Expression
Authors: De Cáceres I. Ibáñez , Priego T. , Martín A. I. , López‐Calderón A. , Villanúa M. A.
Published: November 2003

Experimental arthritis induced by Freund‐adjuvant administration is a model of chronic inflammation and rheumatoid arthritis associated with a decrease in pituitary growth hormone (GH) and hepatic insulin‐like growth factor I (IGF‐I) gene expression. Excessive nitric oxide (NO) synthesis by inducible NO synthase (iNOS) has been implicated in the pathogenesis of inflammatory illness. Moreover, NO participates in the regulation of GH secretion at both the hypothalamus and the pituitary. We have examined the role of iNOS activation in producing the changes in the GH‐IGF‐I axis in arthritic rats. Adult male Wistar rats received aminoguanidine or vehicle from day 20, after adjuvant or vehicle injection, until day 28. Two hours and 30 min after the last aminoguanidine injection, all rats were killed by decapitation. Arthritis increased hypothalamic expression of somatostatin mRNA while it decreased pituitary GH mRNA expression, and both effects were prevented by aminoguanidine administration. In arthritic rats, the parallel decrease in serum IGF‐I, and in hepatic IGF‐I content and mRNA expression, correlates with the decrease in circulating GH concentrations. Aminoguanidine administration to arthritic rats did not modify either serum GH or serum IGF‐I concentrations, or hepatic IGF‐I mRNA expression. However, aminoguanidine administration to control rats resulted in a decrease in serum GH concentrations and in a decrease in both hepatic IGF‐I mRNA expression and serum IGF‐I concentrations. These data suggest that NO mediates the arthritis‐induced decrease in GH mRNA expression by acting at a hypothalamic level, but it is not involved in the decrease in hepatic IGF‐I mRNA expression.
Elevated CO2 mitigates chilling‐induced water stress and photosynthetic reduction during chilling
Authors: BOESE S. R. , WOLFE D. W. , MELKONIAN J. J.
Published: November 2003

Bean, cucumber and corn plants were grown in controlled‐environment chambers at 25/18 °C day/night temperature and either ambient (350 μmol mol−1) or elevated (700 μmol mol−1) CO2 concentration, and at 20–30 d after emergence they were exposed to a 24 h chilling treatment (6.5 ± 1.5 °C) at their growth CO2 concentration. Whole‐plant transpiration rates (per unit leaf area basis) during the first 3 h of chilling were about 26,28 and 13% lower at elevated than at ambient CO2 for bean, cucumber and corn, respectively. The decline in leaf water potential (ψL) and visible wilting of bean and cucumber during chilling were significantly less at elevated than at ambient CO2. Corn ψL was not significantly affected by chilling, and corn did not exhibit any other symptoms of chilling‐induced water stress. Leaf osmotic potentials (measured before chilling only) of bean and cucumber were more negative at elevated than at ambient CO2, and the corresponding calculated leaf turgor potentials were significantly higher at elevated than at ambient CO2. Leaf relative water content (RWC) during chilling at ambient CO2fell to 62 and 48% for bean and cucumber, respectively. RWC during chilling at elevated CO2 was never below 79% for bean or 63% for cucumber. Corn RWC was not measured. After 24 h of chilling at ambient CO2, net photosynthetic rate (PN) reductions were 83, 89 and 24% for bean, cucumber and corn, respectively. PN reductions during chilling were less at elevated CO2: 53, 40 and 4% for bean, cucumber and corn, respectively. At ambient CO2, none of the species fully recovered to pre‐chilling PN, but at elevated CO2 both bean and corn recovered fully. The average percentage leaf area with visible leaf damage due to chilling was 20.6 and 9.6% at ambient and elevated CO2, respectively, for bean, and 32.4 and 23.6% at ambient and elevated CO2, respectively, for cucumber. Corn showed no significant permanent leaf damage from chilling at either CO2 concentration. These results indicate that cucumber was most sensitive to chilling as imposed in this study, followed by bean and corn. The results support the hypothesis that, at least in young plants under controlled‐environment conditions, elevated CO2 improves plant water relations during chilling and can mitigate photosynthetic depression and chilling damage. The implications for long‐term growth and reproductive success in managed and natural ecosystems will require testing of this hypothesis under field conditions.
Seasonal trends of light‐saturated net photosynthesis and stomatal conductance of loblolly pine trees grown in contrasting environments of nutrition, water and carbon dioxide
Authors: MURTHY R. , ZARNOCH S. J. , DOUGHERTY P. M.
Published: November 2003

Repeated measures analysis was used to evaluate the effect of long‐term CO2 enhancement on seasonal trends of light‐saturated rates of net photosynthesis (Asat) and stomatal conductance to water vapour (gsat) of 9‐year‐old loblolly pine (Pinus taeda L.) trees grown in a 2 × 2 factorial experimental design of nutrition and water. A significant interaction effect of CO2 and nutrition on mean Asat was observed for juvenile foliage. Also, juvenile foliage exposed to +350 μmol mol−1 CO2 had a higher rate of increase of Asat between late summer and early autumn. This would lead to a greater potential for recharging carbohydrate reserves for winter. Mature foliage was affected by COsat, water and nutrient treatments in two ways. First, Asat was significantly increased as a result of elevated CO2 in January, a period when stomatal conductance was only 47% of the maximum observed rate. Secondly, the rate of increase of Asat from winter to early spring was accelerated as a result of both nutrient + water and + 350 μmol mol−1 CO2 treatments. This accelerated response resulted in a greater potential for photosynthate production during the period when growth initiation occurred. Nutrient, water or carbon dioxide treatments did not significantly alter trends in gsat for mature or juvenile foliage. A significant nutrition × CO2 interaction was observed for the mature foliage, suggesting that gsat increased with increasing CO2 and nutrition. These results may have important consequences for the determination of the water use efficiency of loblolly pine. In spite of low gsat in the winter to early spring period, there was a substantial gain in Asat attributable to elevated CO2 concentrations.
Photosynthesis and photoprotection in mangroves under field conditions
Authors: CHEESEMAN J. M. , HERENDEEN L. B. , CHEESEMAN A. T. , CLOUGH B. F.
Published: November 2003

Net CO2 exchange and in vivo chlorophyll fluorescence were studied in mangrove (Rhizophora stylosa) leaves at a field site in Western Australia, and leaf samples were collected for the analysis of enzymes and substrates potentially involved in anti‐oxidant photoprotection. Photosynthesis saturated at 900 μmol quanta m−2 s−1 and at no more than 7.5 μmol CO2 m−2 s−1. However, fluorescence analysis indicated no chronic photoinhibition: Fv:Fm was 0.8 shortly after sunset, and quantum efficiencies of PSII were high up to 500 μmol quanta m−2 s−1. Electron flow through PSII was more than 3 times higher than electron consumption through Calvin cycle activity, however, even with photorespiration and temperature‐dependent Rubisco specificities taken into account.

Acknowledging the growing body of literature attributing a role to antioxidant systems in photoprotection, we also assayed the activities of superoxide dismutase (SOD) and several enzymes potentially involved in H2O2 metabolism. Their levels of maximal potential activity were compared with those in greenhouse‐grown mangroves (R. mangle), and growth chamber‐grown peas. Monodehydroascorbate reductase activities were similar in all species, and glutathione reductase was lower, and ascorbate peroxidase ∼40% higher, in the mangroves. SOD activities in field‐grown mangroves were more than 40 times those in peas.

Our results support the hypothesis that O2 may be a significant sink for photochemically derived electrons under field conditions, and suggest an important role for O2− scavenging in photoprotection. However, when relative patterns are compared between species, imbalances between SOD and the other enzymes in the mangroves suggest that more components of the system (e.g. phenolics or peroxidases) are yet to be identified.
Elongation by primary lateral roots and adventitious roots during conditions of hypoxia and high ethylene concentrations
Authors: VISSER E. J. W. , NABBEN R. H. M. , BLOM C. W. P. M. , VOESENEK L. A. C. J.
Published: November 2003

Soil flooding results in unusually low oxygen concentrations and high ethylene concentrations in the roots of plants. This gas composition had a strongly negative effect on root elongation of two Rumex species. The effect of low oxygen concentrations was less severe when roots contained aerenchymatous tissues, such as in R. palustris Sm. R. thyrsiflorus Fingerh., which has little root porosity, was much more affected. Ethylene had an even stronger effect on root elongation than hypoxia, since very small concentrations (0.1 cm3 m−3) reduced root extension in the two species, and higher concentrations inhibited elongation more severely than did anoxia in the culture medium. Thus, ethylene contributes strongly to the negative effects of flooding on root growth. An exception may be the highly aerenchymatous, adventitious roots of R. palustris. Aerenchyma in these roots provides a low‐resistance diffusion pathway for both endogenously produced ethylene and shoot‐derived oxygen. This paper shows that extension by roots of R. palustris in flooded soil depends almost completely on this shoot‐derived oxygen, and that aerenchyma prevents accumulation of growth‐inhibiting levels of ethylene in the root.
Multi‐element and multi‐site isotopic analysis of nicotine from tobacco leaves
Authors: JAMIN E. , NAULET N. , MARTIN G. J.
Published: November 2003

The carbon, nitrogen and hydrogen stable‐isotope contents of nicotine extracted from tobacco leaves were determined by Isotope Ratio Mass Spectrometry (overall 2H, 13C and 15N contents) and by the SNIF‐NMR method (site‐specific deuterium content). In addition, nicotine was chemically degraded into nicotinic acid so that the intramolecular distribution of carbon and nitrogen isotopes could be studied. A prerequisite for reliable measurements is the use of experimental procedures free of isotopic fractionation. Therefore, it was ensured that isotopic integrity was maintained throughout extraction, purification and chemical degradation steps. The multi‐element and multi‐site information provided is tentatively interpreted in terms of biochemical isotopic effects on intramolecular distribution patterns and of the influence of environmental factors on nicotine isotopic parameters.
Interferon‐γ Tempers the Expression of Carcinoembryonic Antigen Family Molecules in Human Colon Cells: a Possible Role in Innate Mucosal Defence
Authors: Fahlgren A. , Baranov V. , Frängsmyr L. , Zoubir F. , Hammarström M.‐L. , Hammarström S.
Published: November 2003

Four carcinoembryonic antigen‐related cell adhesion molecule (CEACAM)s, i.e. CEA, CEACAM1, CEACAM6 and CEACAM7, are localized to the apical glycocalyx of normal colonic epithelium and have been suggested to play a role in innate immunity. The expression of these molecules in colon carcinoma cells was studied at the mRNA and protein levels after treatment with interferon‐γ (IFN‐γ), interleukin‐1β, live bacteria or lipopolysaccharide. The colon carcinoma cell lines LS174T and HT‐29 were studied in detail using real‐time quantitative reverse transcriptase‐polymerase chain reaction, immunoflow cytometry and immunoelectron microscopy. IFN‐γ, but not the other agents, modified expression of CEA, CEACAM1 and CEACAM6. None of the agents upregulated CEACAM7 expression. Two expression patterns were seen. HT‐29 cells, which initially showed low quantities of mRNAs and proteins, displayed marked upregulation of both mRNAs and proteins. LS174T cells transcribed stable high levels of mRNA before and after treatment. Additionally, IFN‐γ induced increased cell surface expression of CEA, CEACAM1 and CECAM6. IFN‐γ has two important effects on the expression levels of the CEA family molecules in colon epithelial cells: direct upregulation of CEACAM1 and promotion of cell differentiation resulting in increased expression of CEA and CEACAM6 and decreased expression of CEACAM7.
Natural Killer Cell‐Mediated Basal and Interferon‐Enhanced Cytotoxicity against Liver Cancer Cells is Significantly Impaired Under In Vivo Oxygen Conditions
Authors: Fink T. , Ebbesen P. , Koppelhus U. , Zachar V.
Published: November 2003

Current immunostimulatory treatment protocols of cancer are often met with little success. Several lines of evidence indicate that the tumour microenvironment may impair the cytotoxic activity of natural killer (NK) cells. In this study, the NK cell‐mediated killing of liver‐derived cells was investigated at oxygen concentrations conform to those present in the human body at physiological and pathological conditions. The in vivo‐relevant oxygen concentrations corresponding to 1, 2 and 6% were compared to those of the ambient air (21%) for their effect on the lysis of four liver‐derived cell lines and the highly susceptible K562 cells. Exposure to each of the hypoxic conditions had a significantly inhibitory effect on NK cytotoxicity. Treatment with interferon‐α (IFN‐α) in hypoxia enhanced the cytotoxic potential of the NK cells less than it enhanced the cytotoxicity at ambient oxygen conditions. In summary, the oxygen tension profoundly affects both the cytoxic activity of NK cells and their activation by IFN‐α.
Microbiology's principle of biofilms as a major factor in the pathogenesis of acne vulgaris
Authors: Burkhart Craig N. , Burkhart Craig G.
Published: November 2003

Propionibacterium acnes reside within the pilosebaceous unit in a biofilm. As such, they live in a community of bacteria that encase themselves within an extracellular polysaccharide lining, which the organisms secrete after adherence to the surface. This gylcocalyx polymer acts as a protective exoskeleton and serves as a physical barrier, limiting effective antimicrobial concentrations within the biofilm microenvironment. The gylcocalyx polymer secreted by P. acnes as a biofilm may explain the immunogenicity of the organism as well as the clinical course of the disease. The P. acnes’ biofilm model explains many aspects of acne pathogenesis and therapy, including why prolonged antibiotic treatment is needed, why antibiotic resistance is not a reliable assessment of treatment outcome, why accutane offers long‐lasting effectiveness, and why benzoyl peroxide radicals are beneficial. This microbiologic principle of biofilms as applied to acne leads to numerous new pathways of assessment and exploration.
Microglial activation with atypical proinflammatory cytokine expression in a rat model of Parkinson's disease
Authors: Depino Amaicha M. , Earl Chris , Kaczmarczyk Elke , Ferrari Carina , Besedovsky Hugo , Del Rey Adriana , Pitossi Fernando J. , Oertel Wolfgang H.
Published: November 2003

Microglial activation has been associated with the pathogenesis of Parkinson's disease (PD). Among the many components of this reaction, cytokines have been proposed as candidates to mediate neurodegenerative or neuroprotective effects. We investigated the interleukin‐1 system and tumour necrosis factor‐α mRNA and protein levels at different time intervals in the subacute intrastriatal 6‐hydroxydopamine rat model of PD, in parallel with the inflammatory response. Immunohistochemistry showed that microglial cells were activated from days 6–30 postlesion in the substantia nigra pars compacta. This microglial activation was accompanied by an atypical proinflammatory cytokine production: Interleukin‐1α and β mRNAs were found to be elevated 30 days post‐6‐hydroxydopamine injection (2‐ and 16‐fold, respectively), but no induction for interleukin‐1α or β at the protein level was detected by ELISA. As a control, a classical proinflammatory stimulus, namely endotoxin, was capable of inducing these cytokines at similar mRNA levels but also at the protein level. In addition, tumour necrosis factor‐α mRNA was hardly or not detected in the substantia nigra at any time point studied. Our data point out a tight control of key proinflammatory cytokine production in our model of PD. This work supports the notion that chronic neuronal death per se does not induce secretion of these proinflammatory cytokines but that an additional stimulus is necessary to stimulate proinflammatory cytokine production. The production of proinflammatory cytokines from “primed” microglia may in turn modulate disease progression as has been recently proposed in a model of prion disease.
Gradient of adaptability in four different motor systems performing the same learned motor task in cats
Authors: Gruart Agnès , Streppel Michael , Guntinas‐Lichius Orlando , Angelov Doychin N. , Neiss Wolfram F. , Delgado‐García José M.
Published: November 2003

The ability of four different brainstem motoneuron pools to perform a newly acquired motor task was studied in alert cats. A classical conditioning of eyelid responses was carried out in (i) unoperated animals, and in animals with (ii) transection, 180° rotation, and re‐suture of the zygomatic facial nerve branch, (iii) a crossed anastomosis of the buccal to the zygomatic facial nerve branch and (iv) a hypoglossal–facial nerve anastomosis. Animals were conditioned with a delay paradigm using a tone (350 ms, 600 Hz, 90 dB) as conditioned stimulus, followed 250 ms later by an air puff (100 ms, 3 kg/cm2) as unconditioned stimulus. Animals with zygomatic nerve rotation performed conditioned responses (CRs) at control rate, with significantly larger amplitude, area and velocity, but a de‐synchronized oscillatory pattern. Animals with buccal–zygomatic anastomosis acquired CRs at control rate, but these CRs had significantly smaller amplitude than those of controls and a de‐synchronized pattern. Animals with a hypoglossal–facial anastomosis were unable to perform CRs. The trigeminal hyper‐reflexia triggered by the axotomy was probably the origin of the large CRs after zygomatic nerve rotation. Trigeminal hyper‐reflexia could also contribute to generation of the small CRs recorded after buccal–zygomatic anastomosis. Although trigeminal hyper‐reflexia was also present following hypoglossal–facial anastomosis, hypoglossal motoneurons did not reach their firing threshold to perform CRs. In accordance with the embryonic origin of involved motoneurons, animals with buccal–zygomatic and hypoglossal–facial anastomoses moved the ipsilateral eyelid synchronously to mouth‐related activities. It is suggested that there is a gradient of adaptability in motoneuron pools forced to perform new motor tasks through foreign muscles, which depends on their embryological origins and functional properties.
Delay‐period activities in two subdivisions of monkey inferotemporal cortex during pair association memory task
Authors: Naya Yuji , Yoshida Masatoshi , Takeda Masaki , Fujimichi Ryoko , Miyashita Yasushi
Published: November 2003

The macaque inferotemporal cortex, which is involved in encoding and retrieval of visual long‐term memory, consists of two distinct but mutually interconnected areas: area TE (TE) and area 36 (A36). In the present study, we compared delay‐period activities of the two subdivisions in terms of their signal contents. We recorded single‐unit activities from TE and A36 during a delayed pair association task, in which monkeys were required to choose the paired associate of a cue stimulus after a delay period. The stimulus‐selective delay‐period activities of single neurons were characterized by using partial correlation coefficients of delay‐period activities for each cue stimulus with the cue‐period responses to that stimulus (cue‐holding index, CHI) and with the cue‐period responses to its paired associate (pair‐recall index, PRI). The delay‐period activities of TE neurons preferentially represented the paired associate (PRI, median = 0.54) rather than the cue stimulus itself (CHI, 0.23) (P < 0.001, n = 70), while the delay‐period activities of A36 neurons retained both the cue stimulus and its paired associate equivalently (CHI, 0.44; PRI, 0.46) (P = 0.78, n = 38). These results indicate that the signal contents of delay‐period activities differ between the two subdivisions: TE mostly represents a sought target that is retrieved from long‐term memory, while A36 in addition retains cue‐stimulus that is transmitted from earlier visual areas.
Chemokine modulation of high‐conductance Ca2+‐sensitive K+ currents in microglia from human hippocampi
Authors: Bordey A. , Spencer D. D.
Published: November 2003

During acute pathological processes, microglia transform into an activated state characterized by a defined morphology and current profile, and are recruited to injury sites by chemokines. No information is available on the ion channels and the mode of action of chemokines in microglia in brain slices from humans with a chronic pathology. Thus, patch‐clamp recordings of microglia were performed in hippocampal slices from seven patients who underwent surgery for pharmaco‐resistant epilepsy. Cells were identified as microglia by positive labelling with fluorescein‐conjugated tomato lectin before recording. All the recorded cells had an ameboid morphology characteristic of activated microglia. However, they had a high input resistance (3.6 GΩ), a zero‐current resting potential of −16 mV, and lacked Na+ currents, inwardly rectifying and delayed rectifying K+ currents such as non‐activated microglia. Importantly, recorded cells expressed Ca2+‐sensitive outward currents that activated at 0 mV with non‐buffered intracellular Ca2+ and were sensitive to 1 mm tetraethylammonium (TEA). The estimated single‐channel conductances were 187 pS in cell‐attached and 149 pS in outside‐out patches, similar to those of high‐conductance Ca2+‐dependent K+ channels. The chemokine MIP1‐α increased whole‐cell outward current amplitudes measured at +60 mV by a factor of 3.3. Thus, microglia in hippocampi from epileptic patients express high‐conductance Ca2+‐dependent K+ channels that are modulated by the chemokine MIP1‐α. This modulation may contribute to the migratory effect of MIP1‐α on microglia.