bluuebunny/crossref_metadata_2025 huggingface dataset:
Facial swelling and gingival enlargement in a patient with sickle cell disease
Authors: Scipio JE , Al‐Bayaty HF , Murti PR , Matthews R
Published: March 2003

Sickle cell anemia is a frequent hemoglobinopathy in the Caribbean. While vaso‐occlusion induced tissue injury in sickle cell anemia is common in various organs, orofacial lesions are rare. A 14‐year‐old Afro‐Trinidadian boy suffering from sickle cell anemia developed an acute facial swelling, mimicking facial cellulitis of dental origin, which was caused by sickle cell‐related hemorrhage. He also exhibited gingival enlargement, considered to be an outcome of repeated hemorrhagic episodes and fibrous repair. A new finding is the presence of erythrocyte‐filled intraepithelial blood vessels in the gingival epithelium. We hypothesize this phenomena is a tissue response to hypoxia that occurs in sickle cell disease.
Mechanisms of expression of HHV8, EBV and HPV in selected HIV‐associated oral lesions
Authors: Hille JJ , Webster‐Cyriaque J , Palefski JM , Raab‐Traub N
Published: March 2003

Opportunistic DNA viruses, particularly members of the herpesvirus family, are frequently the aetiological agents of HIV‐associated oral lesions. Oral lesions common to the early phase of the AIDS epidemic, including Kaposi's sarcoma (KS), oral aphthous ulceration, AIDS‐associated oral lymphoma, and oral hairy leukoplakia (OHL), have been tested for the prevalence of Epstein–Barr virus (EBV) and Kaposi's sarcoma‐associated herpesvirus (KSHV). While EBV DNA is detected by PCR in all of these lesions, abundant viral replication can only be detected in OHL. In OHL, a novel state of EBV infection has been discovered with concurrent expression of replicative and transforming proteins, with all of these proteins contributing to the development of the lesion. Activation of signalling pathways and up‐regulation of the viral receptor, proliferative and antiapoptotic genes by these proteins induce several of the histological features common to OHL, such as acanthosis and hyperproliferation. In contrast to other permissive herpesvirus infections, expression of EBV transforming proteins within the permissively infected OHL tissue enables epithelial cell survival and may enhance viral replication. Detection of KSHV in these HIV‐infected individuals has been localized only to their saliva. Replicative and latent KSHV gene products have been detected in association with the development of oral KS lesions. EBV, but not human cytomegalovirus (HCMV), has been detected by PCR in minor salivary gland biopsies of HIV‐associated salivary gland disease. Human papillomaviruses (HPV) are associated with oral warts in HIV‐positive individuals; a diagnosis that appears to be increasing in frequency in the era of highly active antiretroviral therapy. To date, there appears to be little increase in the incidence of HPV‐associated oral cancer. The mechanisms of interaction between HIV and HPV are not fully understood. Expression of viral gene products is clearly important and necessary for the development of multiple AIDS‐associated oral lesions.
Bacterial and yeast flora of root surface caries in elderly, ethnic Chinese
Authors: Shen S , Samaranayake LP , Yip HK , Dyson JE
Published: March 2003

OBJECTIVES: Root caries is emerging as a significant problem in the middle aged and elderly. As little data is available on the microbiology of root caries in Chinese cohorts, we evaluated 30 such lesions in elderly, institutionalized, ethnic Chinese.

METHODS: Samples of carious dentine were aseptically taken from root caries lesions of 18 subjects (five males and 13 females, mean age 79.67 ± 8.57). The cultivable bacteria, both aerobic and anaerobic, were isolated and identified using standard methods and commercial identification kits. The yeasts were isolated on Sabouraud's agar and identified using the API system.

RESULTS: The main findings were: (1) of the total isolates, 91.09% were Gram‐positive and 8.91% were Gram‐negative microorganisms; (2) the proportions of cocci and rods were 36.68 and 63.31%, respectively; (3) the predominant groups of organisms isolated were Streptococcus spp., Lactobacillus spp., Staphylococcus spp. and Actinomyces spp. with isolation frequencies of 100, 90.00, 73.33 and 63.33%, respectively; (4) the isolation frequency of yeasts belonging to Candida spp. (63.33%) was notably high although the proportion of yeasts within each sample was low (0.01%). Candida dubliniensis, a newly identified yeast species particularly prevalent in HIV infection, comprised 14.29% of yeasts.

CONCLUSIONS: This study provides baseline information on the microbiologic features of root caries in the elderly, ethnic Chinese. Whilst our data on the most predominant bacteria isolated in root caries concur with those from other regions of the world the isolation of C. dubliniensis from these lesions has not been documented before.
Oral non‐Hodgkin lymphomas: studies of EBV and p53 expression
Authors: Iamaroon A , Pongsiriwet S , Mahanupab P , Kitikamthon R , Pintong J
Published: March 2003

OBJECTIVES:  The aims of the study were to assess sociodemographic and clinicopathologic characteristics of patients with oral non‐Hodgkin lymphomas (NHLs) and the expression of Epstein–Barr virus (EBV) and p53.

MATERIALS AND METHODS:  The clinical and pathologic features of 11 patients with oral NHLs were studied. The expression of EBV mRNA and p53 protein were studied by means of in situ hybridization and immunohistochemical methods in 11 formalin‐fixed, paraffin‐embedded specimens from these patients.

RESULTS:  The patients’ age ranged from 13 to 70 years with the mean of 42 years. Human immuno‐deficiency virus (HIV) status was documented in five of the 11 patients and three were known to be HIV‐positive. The most common locations were gingiva and alveolar mucosa. Pain and tenderness were major symptoms of the patients. The most common histologic subtype was diffuse large‐cell, intermediate‐grade NHL. Eight of 11 cases (72.7%) showed positive expression of p53 protein. Four of 10 cases (40%) expressed EBV‐encoded RNA (EBER) transcripts. All known HIV‐positive cases were EBV‐positive.

CONCLUSIONS:  The findings suggest that appropriately expressed p53 protein may play a role in tumorigenesis of oral NHLs. In addition, EBV may be involved with the pathogenesis of oral NHLs particularly in patients with HIV infection.
Percent of plaque on individual tooth surfaces and differences in plaque area between adjacent teeth in healthy adults
Authors: Söder Birgitta , Johannsen Annsofi , Lagerlöf Folke
Published: March 2003

Abstract  

Objectives:  To apply a planimetric method to determine the percentage of the tooth area covered by plaque on individual tooth surfaces and to compare the percentage of plaque between adjacent tooth surfaces.

Methods: Forty‐three adults, mean age 43.0 years, with no signs of periodontal disease, participated. The subjects underwent comprehensive professional cleaning of all teeth. The subjects were then instructed to maintain their ordinary oral hygiene habits. Plaque was registered after 1 month, on each individual tooth surface by use of P%I.

Results: The pattern of plaque accumulation was in large symmetrical, with differences in mean P%I between several adjacent tooth surfaces, e.g. for the maxillary buccal and lingual tooth surfaces between the first and second molars (P < 0.001) and for the lingual tooth surfaces between the canines and the first premolars (P < 0.01).

Conclusion: In the present study, it was possible to identify and describe adjacent tooth surfaces with the most pronounced plaque accumulation, to make further improvements of oral hygiene possible.
Pneumonia Versus Aspiration Pneumonitis in Nursing Home Residents: Diagnosis and Management
Authors: Mylotte Joseph M. , Goodnough Susan , Naughton Bruce J.
Published: March 2003

OBJECTIVES: To determine the frequency of aspiration pneumonitis in nursing home residents with an initial diagnosis of pneumonia and to compare the clinical characteristics, management, and outcome of aspiration pneumonitis with those of pneumonia.

DESIGN: Retrospective chart review.

SETTING: Hospital geriatric unit for nursing home residents.

PARTICIPANTS: Nursing home residents admitted to the inpatient geriatric unit with suspected pneumonia between May 1999 and April 2001 (n = 195 episodes).

MEASUREMENTS: Aspiration events were defined as definite (witnessed or unwitnessed) or suspected. Aspiration pneumonitis was defined as symptoms/signs of lower respiratory tract infection plus a history of an aspiration event plus a lower lobe infiltrate on chest radiograph. Pneumonia was defined as symptoms/signs of lower respiratory tract infection plus an infiltrate on chest radiograph plus no history of an aspiration event.

RESULTS: The 195 episodes were stratified into three clinical groups: aspiration pneumonitis (n = 86; aspiration history/infiltrate), pneumonia (n = 43; no aspiration history/infiltrate), and an aspiration event (n = 66; aspiration history/no infiltrate). In general, symptoms, signs, and laboratory tests were not useful in distinguishing between the three groups. Survivors with aspiration pneumonitis (13/75 (17%)) or with an aspiration event (20/60 (33%)) were significantly more likely not to be treated with an antibiotic or to be treated for 1 day or less than those with pneumonia (0/41; P < .001). Excluding those not treated, significantly more patients with pneumonia (33/40 (83%)) were discharged on antibiotic treatment than those with aspiration pneumonitis (35/70 (50%)) or an aspiration event (21/51 (41%); P < .001). There was no significant difference in hospital mortality between the three clinical groups.

CONCLUSIONS: The findings of this study have implications for the diagnosis and management of suspected pneumonia in nursing home residents but require prospective validation.
Amnestic Behavior in Dementia: Symptoms to Assist in Early Detection and Diagnosis
Authors: Ready Rebecca E. , Ott Brian R. , Grace Janet
Published: March 2003

OBJECTIVES: This study evaluated two amnestic behavior changes (repetitive questioning and repetitive actions) to determine their utility in screening for early dementia.

DESIGN: Patient data were collected through a retrospective chart review. Comparison data from nondemented older people were collected prospectively from acquaintances of clinic patients.

SETTING: The setting was a hospital‐based outpatient memory disorder clinic.

PARTICIPANTS: Participants were older individuals with no cognitive impairment (n = 25), undetermined dementia (n = 50), and definite dementia (n = 25). The undetermined cases were followed for at least 1 year to assess for conversion to dementia.

MEASUREMENTS: Amnestic behaviors were assessed using informant‐report for all participants. The behaviors were examined for their ability to distinguish between definite dementia cases and noncases. They were further evaluated for the ability to differentiate undetermined cases that eventually converted to definite dementia from cases that did not convert.

RESULTS: Results indicated that repetitive behaviors were common in early and more‐severe dementia cases. Repetitive behaviors were relatively uncommon in cognitively intact older participants. In analyses of the full study sample, engagement in repetitive behaviors had high sensitivity (0.97) in identifying dementia cases.

CONCLUSIONS: Assessing repetitive behaviors in patients may be a useful means for family members and primary care physicians to screen for early cognitive impairment. The assessment can help to identify individuals that should be evaluated further for dementia.
Multiple roles for kinases in DNA replication
Authors: Henneke Ghislaine , Koundrioukoff Stéphane , Hübscher Ulrich
Published: March 2003

DNA replication is carried out by the replisome, which includes several proteins that are targets of cell‐cycle‐regulated kinases. The phosphorylation of proteins such as replication protein A, DNA polymerase‐α and ‐δ, replication factor C, flap endonuclease 1 and DNA ligase I leads to their inactivation, suggesting that phosphorylation is important in the prevention of re‐replication. Moreover, the phosphorylation of several of these replication proteins has been shown to block their association with the ‘moving platform’—proliferating cell nuclear antigen. Therefore, phosphorylation seems to be a crucial regulator of replisome assembly and DNA replication, although its precise role in these processes remains to be clarified.
The N-terminus of the human copper transporter 1 (hCTR1) is localized extracellularly, and interacts with itself
Authors: KLOMP Adriana E.M. , JUIJN Jenneke A. , GUN Linda T.M. van der , BERG Inge E.T. van den , BERGER Ruud , KLOMP Leo W.J.
Published: March 2003

We have used indirect immunofluorescense studies and glycosylation-site insertion and deletion mapping to characterize the topology of human copper transporter 1 (hCTR1), the putative human high-affinity copper-import protein. Both approaches indicated that hCTR1 contains three transmembrane domains and that the N-terminus of hCTR1, which contains several putative copper-binding sites, is localized extracellularly, whereas the C-terminus is exposed to the cytosol. Based on previous observations that CTR1 proteins form high-molecular-mass complexes, we investigated directly whether CTR1 proteins interact with themselves. Yeast two-hybrid studies showed that interaction of yeast, mouse, rat and human CTR1 occurs at the sites of their N-terminal domains, and is not dependent on the copper concentration in the growth media. Analysis of deletion constructs indicated that multiple regions in the N-terminus are essential for this self-interaction. In contrast, the N-terminal tail of the presumed low-affinity copper transporter, hCTR2, does not interact with itself. Taken together, these results suggest that CTR1 spans the membrane at least six times, permitting formation of a channel, which is consistent with its proposed role as a copper transporter.
Mitochondrial threshold effects
Authors: ROSSIGNOL Rodrigue , FAUSTIN Benjamin , ROCHER Christophe , MALGAT Monique , MAZAT Jean-Pierre , LETELLIER Thierry
Published: March 2003

The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the ‘phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the ‘biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a ‘translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases.
Regulation and Expression of Progesterone Receptor mRNA Isoforms A and B in the Male and Female Rat Hypothalamus and Pituitary Following Oestrogen Treatment
Authors: Scott R. E. M. , Wu‐Peng X.‐S. , Pfaff D. W.
Published: March 2003

Progesterone receptors play a central role in neuroendocrine and behavioural regulation. To gain insight into the sex‐ and tissue‐specific regulation of progesterone receptors, protein binding on a progesterone receptor‐oestrogen response element and mRNA levels for progesterone receptor (PR)‐A and PR‐B were compared between female and male rats following oestradiol benzoate replacement treatment in hypothalamic and pituitary tissue. Both male and female pituitary protein extracts demonstrated an increase in nuclear protein binding activity to a progesterone receptor‐oestrogen response element following oestradiol benzoate treatment. However, there was a greater difference in total binding activity seen in the female pituitary extracts compared to male pituitary protein extracts. In both cases, reflecting the binding data, oestradiol benzoate pretreatment led to an increase in pituitary PR‐B messenger RNA, although this increase was significantly larger in females than in males. Oestradiol benzoate treatment also led to a significant increase in specific binding of hypothalamic nuclear proteins to the progesterone receptor oestrogen response element from both females and male hypothalamic extracts. In addition, PR‐B messenger RNA was induced by oestradiol benzoate treatment in the female rat hypothalamus, under circumstances where no PR‐A could be detected. The male also demonstrated an increase in PR‐B messenger RNA following oestradiol benzoate treatment, with undetectable levels of PR‐A, although to a lesser degree than that seen in the female. The predominance of PR‐B over PR‐A messenger RNA in rat hypothalamus and pituitary, and the quantitative differences between female and male rats, could both contribute to the greater responsiveness of female rats to progesterone with respect to control over luteinizing hormone release from the pituitary, and lordosis behaviour regulated by hypothalamic neurones.
Transgenic Brassica napus plants overexpressing aluminium‐induced mitochondrial manganese superoxide dismutase cDNA are resistant to aluminium
Authors: Basu U. , Good A. G. , Taylor G. J.
Published: March 2003

We investigated the role that manganese superoxide dismutase (MnSOD, EC 1·15·1·1), an important enzyme of the antioxidant pathway, may play in aluminium (Al) toxicity/resistance. A wheat (Triticum aestivum) cDNA (WMnSOD) was cloned and up‐regulation of the transcript was observed in root tips after 24 h exposure to 100 µm Al. The WMnSOD1 under the control of the CaMV35S promoter was expressed in canola (Brassica napus). Transgenic plants were phenotypically normal. Northern analyses showed enhanced levels of the WMnSOD1 and WMnSOD1‐GUS transcripts and total SOD activity was 1·5‐ to 2·5‐fold greater in transgenic plants than in wild type (WT) plants. Transgenic (T1) leaf discs showed increased retention of chlorophyll and reduced electrolyte leakage when exposed to methyl viologen (MV) as compared with WT leaf discs, suggesting that transgenic plants were more resistant to oxidative stress. When WT canola plants were exposed to aluminium (0–200 µm), inhibition of root growth, higher SOD activity and increased levels of malondialdehyde (MDA, an indicator of lipid peroxidation) were observed in roots. Aluminium‐induced inhibition of root growth and accumulation of MDA was lower in homozygous transgenic plants (T2) compared with WT plants. Transgenic lines also showed lower synthesis of 1,3‐β‐glucans (callose, a sensitive marker for Al injury) as compared with WT. These data suggest that resistance to Al toxicity can be improved by overexpressing WMnSOD1.
Local annual survival of booming male Great Bittern Botaurus stellaris in Britain, in the period 1990–1999
Authors: Gilbert Gillian , Tyler Glen A. , Smith Ken W.
Published: March 2003

Male Great Bitterns Botaurus stellaris have individually distinctive boom vocalizations which have been used since 1990 to count the British population accurately. We used vocal individuality to identify birds between years and analyse the survival of the British booming population. We used six instances of Great Bitterns known to be the same birds (from radio tracking and re‐sighting of darvic rings) in successive years to provide a means of identification independent from vocalizations. All of these birds remained in the same territory from one year to the next. Seven spectrogram measures were chosen as quantitative descriptors of Great Bittern booms. Boom similarity was expressed in terms of Euclidean ‘acoustic’ distance between descriptors of pairs of birds. Great Bitterns that were known to be the same birds had more similar booms across years than those known to be different. The acoustic distances and knowledge of site fidelity were used to construct parsimonious rules on which to base re‐identification decisions and to build survival histories. Great Bittern local survival in Britain as a whole was estimated as 70% (± 5.1 se) with survival in north‐west England (at Leighton Moss) higher (82.8%, ± 7.3 se) than that in East Anglian sites (65.2%, ± 5.4 se) (χ12 = 3.4, P = 0.07). Movements of males between years were apparent between sites within the Suffolk and Norfolk coastal regions but not on a large scale. Survival of adult males in East Anglia was positively related to winter rainfall, but there was no significant relationship with winter temperature. There was a positive relationship between the annual population change in East Anglia and the annual local adult survival rate.
Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases define the migratory characteristics of human monocyte‐derived dendritic cells
Authors: Osman Mohamed , Tortorella Micky , Londei Marco , Quaratino Sonia
Published: March 2003

Dendritic cells (DCs) have an essential role in the initiation of immune responses as they deliver antigen/epitope and the appropriate signals to activate naïve T cells and thus start an immune response. In order to fulfil their function, DCs have to patrol different part of the body, thus migrating through the extracellular matrix to sample the local ‘antigenic’ environment. In the present study, we have investigated which enzymes might be involved in this process using the Matrigel trans‐well migration assay, an in vitro model of extracellular matrix migration. In this assay we analysed the migratory ability of interleukin‐4 (IL‐4)/granulocyte macrophage–colony‐stimulating factor (GM‐CSF)‐derived immature DCs as well as mature DCs, induced by tumour necrosis factor‐α (TNF‐α) and modified vaccinia virus Ankara (MVA). The ‘mature’ DCs showed an increased migration through Matrigel, which was significantly inhibited by inhibitors of matrix metalloproteinases (MMP). We also observed that the dominant MMP involved in this process was MMP‐9, and a concomitant decrease of the endogenous tissue inhibitors of metalloproteinases (TIMP)‐1 and TIMP‐2 was also observed. Collectively these data suggest that the balance between MMP/TIMP determines the net migratory capacity of human DCs. Surprisingly, TIMP‐3 was significantly increased in mature DC. Our data thus indicate that MMP and TIMP play a role in the migratory ability of human DCs. Our results also suggest that TIMP‐3 expression might represent a new marker of maturation of human DCs.
Morphometric and immunohistochemical characterization of the intimal layer throughout the arterial system of elderly humans
Authors: Vink Aryan , Schoneveld Arjan H. , Poppen Marieke , De Kleijn Dominique P. V. , Borst Cornelius , Pasterkamp Gerard
Published: March 2003

The purpose of the present study was to obtain insight into the natural development of adaptive intimal thickening and atherosclerosis in the arterial tree of human species. The morphometry and composition of the intimal layer were studied in the arterial system of elderly individuals. Post mortem, a total of 703 arterial segments were dissected from 24 subjects (age 81.9 ± 9.9 years). From each subject, segments were dissected from 31 different arteries. Area stenosis [(plaque area/vessel area) × 100%] was determined in each segment. By (immuno)histochemistry, lipid content and the presence of inflammatory cells (macrophages) were assessed in the coronary, common carotid, brachial, radial and internal iliac arteries. Adaptive intimal thickening or advanced atherosclerosis was observed in all studied artery types. Area stenosis was highest in the coronary arteries (median, 30%) and lowest in the arteries supplying the brain (median, ≤ 7%). Plaques hiding a lipid‐rich core and plaques with macrophage infiltration were observed in all five selected artery types. In summary, the present observation demonstrates that intimal thickening is a systemic process involving most artery types. Within elderly humans, features of advanced atherosclerotic disease, a lipid‐rich core and macrophages, can be observed in the intimal layer of artery types that are recognised for their relation with clinical syndroms as well as artery types that remain clinically silent.
Behavioural factors affecting foraging effort of breeding wandering albatrosses
Authors: Shaffer Scott A. , Costa Daniel P. , Weimerskirch Henri
Published: March 2003

The study examined the behavioural factors that influence variation in foraging costs of wandering albatrosses (Diomedea exulans Linnaeus) during two consecutive years. This was performed by measuring simultaneously foraging activities and metabolic rates (W kg−1) of breeding birds during the incubation periods of 1998 and 1999.

 A total of 38 birds (19 in each year) were injected with doubly labelled water, equipped with satellite transmitters to measure foraging distance and flight speed, and equipped with activity recorders to measure landings and take‐offs from the water surface.

 In 1999, birds spent on average 30% more time at sea (11·07 ± 3·53 SD, days), travelled 43% further (5473 ± 2348 SD, km) and increased the number of landings and take‐offs per day by 66% (28·1 ± 11·4 SD, landings per day) compared to 1998.

 Energy expenditure rates during foraging were significantly higher in 1999 (5·3 ± 0·8 SD, W kg−1, n = 8) compared to 1998 (4·5 ± 0·5 SD, W kg−1, n = 11).

 Landing and take‐off rates explained the greatest proportion of variation in energy expenditure rates of wandering albatrosses, rather than total distance travelled, flight speed or time in flight.

 Despite 18% higher foraging costs in 1999, the daily rate of food intake was similar between years, suggesting that energy acquisition per unit effort was lower.

 The energetic cost of flight for wandering albatrosses was estimated to fall between 3·4 and 5·1 W kg−1, or 1·4–2·0 × measured BMR, one of the lowest flight cost yet reported for any seabird.
Do female coleopteran parasitoids enhance their reproductive success by selecting high‐quality oviposition sites?
Authors: Fournet S. , Poinsot D. , Brunel E. , Nénon J. P. , Cortesero A. M.
Published: March 2003

Female parasitoids that lay their eggs away from potential host insects are supposed to have only a minor influence on the fitness of their own progeny, as they do not select and evaluate directly the quality of hosts for their offspring. Aleochara bilineata Gyll. (Coleoptera: Staphylinidae) females oviposit near to cabbage plants infested by larvae of Delia radicum L. (Diptera: Anthomyiidae). Once the mobile A. bilineata larva emerges from the egg, it must then search the soil to find and select a suitable fly pupa. The beetle larvae have a limited time to found pupae and can only parasitize one host pupa during their lifetime. Moreover, because A. bilineata is a solitary parasitoid whether or not the host pupa is parasitized, has a strong influence on the successful development of the beetle larva.

We studied the oviposition behaviour of A. bilineata females in laboratory experiments in which females could choose between a range of several oviposition sites.

Our results reveal that A. bilineata females, like hymenopteran parasitoid females, show an adaptive oviposition behaviour in response to the quality of the oviposition site. The female beetles adapt their oviposition decisions and their clutch size based on information associated with the presence of a host. Furthermore, our results reveal that the Aleochara females can discriminate between specific cues related to the stage and parasitization status of the host. Such behaviours may greatly enhance the parasitization success of the larvae, and thereby female fitness.
Ecology of fruit‐colour polymorphism in Myrtus communis and differential effects of birds and mammals on seed germination and seedling growth
Authors: Traveset Anna , Riera Núria , Mas Rafael E.
Published: March 2003

The fruit‐colour polymorphism of Myrtus communis, a common Mediterranean shrub, is examined. We investigate whether frugivores affect the maintenance of the polymorphism, whether morphs differ in germination or seedling growth, and whether passage through frugivores’ gut affects seed behaviour and seedling growth.

Blue berries are very similar in morphological traits and nutrient composition to the rarer white morph. Rates of fruit removal by birds, the main dispersers of this species, did not differ between morphs, suggesting that a colour preference is not involved in maintenance of the polymorphism.

Seeds of the two morphs showed the same germinability (final percentage germination) as well as similar rates of germination under controlled conditions (in growth chamber and greenhouse). Outdoors, seeds from blue berries tended to germinate slightly faster (which might give them an early advantage) but differences between morphs disappeared after several weeks of growth.

The germination of myrtle seeds is differently affected by passage through the digestive tract of birds, which appeared to significantly increase germinability, and of the carnivorous pine marten, Martes martes, which did not. The different seed retention time in the gut or the chemical composition of the food ingested along with the seeds may be responsible for such differences.

The detection of a positive effect of bird ingestion in outdoor conditions, but not in the growth chamber or in the greenhouse, demonstrates the importance of performing germination tests in the natural habitat.

Seed size, irrespective of morph, affects the response to passage through the bird gut. Large seeds, which are more rapidly ejected, and are thus less abraded, germinated at a similar speed to non‐ingested controls. Variation in seed size within a single species should thus be considered in future studies.
Abrupt vegetation changes in the Segura Mountains of southern Spain throughout the Holocene
Authors: Carrión J. S. , Munuera M. , Dupré M. , Andrade A.
Published: March 2003

The fossil pollen record of Cañada de la Cruz in the Segura mountains of southern Spain yields insights into high‐elevation vegetational dynamics over the last c. 8320 years. Phases of xerophytic grassland alternate with high‐mountain open pine forests and expansion of deciduous forests and Mediterranean scrub at lower altitudes.

Longer‐term stable vegetation patterns are interrupted by multidecadal to century‐scale shifts at about 7770, 3370, 2630, 1525 and 790 years BP.

Some of the vegetation types have no modern analogues and represent high‐altitude remnants of widespread last‐glacial xerophytic communities. Other species patterns, characteristic of current scrub associations, appeared only within the last 800 years.

The sequence fits within the regional context of a generally wet mid‐Holocene (c. 7700–3300 years BP) characterized by spread of mesophilous vegetation, between drier conditions characterized by greater abundance of xerophytes.

The pollen record and current ecological studies on high‐elevation vegetation of Mediterranean Spain suggest that control of vegetation is primarily climatic although grazing pressure, which would have pushed vegetation over a threshold for change, cannot be discounted.
Forest canopy and community dynamics in a temperate old‐growth evergreen broad‐leaved forest, south‐western Japan: a 7‐year study of a 4‐ha plot
Authors: Miura Masahiro , Manabe Tohru , Nishimura Naoyuki , Yamamoto Shin‐ichi
Published: March 2003

Forest canopy gap and community dynamics were studied in a 4‐ha permanent plot of an old‐growth evergreen broad‐leaved forest dominated by Castanopsis cuspidata var. sieboldii and Distylium racemosum in the Tatera Forest Reserve, Tsushima Islands, south‐western Japan. The forest was affected by a powerful typhoon in 1987 and was monitored from 1990 to 1997.

In 1990, all woody stems ≥ 5 cm diameter at breast height (d.b.h.) in the plot were identified, mapped and marked, and the state of 1600 5 m × 5 m contiguous quadrats used to locate canopy gaps. Gaps occupied 17.1% of the plot, which contained 4494 tree and shrub stems (total basal area 63.48 m2 ha−1). Gaps were re‐censused in 1997 and both marked and newly recruited (≥ 5 cm d.b.h.) stems were recorded in 1992 and 1997.

Over 7 years the rates of canopy gap formation and closure were 0.72% year−1 and 1.61% year−1, respectively, mortality and recruitment rates were 0.97% year−1 and 0.99% year−1, and the rates of loss and gain in basal area were 0.95% year−1 and 0.83% year−1.

The mortality of stems was size‐dependent, with those in middle size classes having the lowest rates. Mortality of stems was lower in canopy and higher in the understorey, while the proportion of stems killed by disturbances increased with height.

Stems that died during the 7 years were predominantly located in newly created gaps, whereas stems were recruited into both established and new gaps. Deciduous broad‐leaved species were largely restricted to gaps that remained open throughout the study.

Both composition and structure of the forest changed in response to disturbance‐related effects on canopy dynamics.
Rapid recent range‐margin rise of tree and shrub species in the Swedish Scandes
Authors: Kullman Leif
Published: March 2003

Recent elevational range‐margin performance of tree and shrub species was studied at a site in the Swedish Scandes. The methods included comparisons of historical and present‐day range‐margin records (m a.s.l.) in conjunction with age‐determination of newly established saplings.

Since the early 1950s, the range‐margins ofBetula pubescensssp.tortuosa(mountain birch),Picea abies(Norway spruce),Pinus sylvestris(Scots pine),Sorbus aucuparia(rowan) andSalixspp. (willows) have advanced by 120–375 m to colonize moderate snow‐bed communities. The non‐nativeAcer platanoides(Norway maple) has become established just below the birch forest‐limit. In concert with tree‐limit rises by 100–150 m in the same region, the present results suggest a shift in reproduction and a significant break in the late‐Holocene vegetation history.

Ring‐counting (in 2000) of a subsample of the recovered saplings revealed that, with one exception, they were aged between 7 and 12 years, i.e. they germinated after 1987. Since 1988 there has been strong and consistent winter warming, with some very warm summers, and this may ultimately have forced the vegetational changes.

Reduced summer snow‐retention has favoured seedling establishment and juvenile growth, and mild winters, with reduced risk of frost‐desiccation, have enhanced survivorship and height increment.

Certain seed‐regenerating tree and shrub species have tracked recent climate change quite rapidly and more sensitively than vegetatively propagating field‐layer species. Such species‐specific responses may give rise to novel high‐elevation vegetational patterns in a hypothetically warmer future world.
Measurement of the three‐dimensional microscope point spread function using a Shack–Hartmann wavefront sensor
Authors: Beverage J. L. , Shack R. V. , Descour M. R.
Published: March 2003

We present a technique to measure the wavefront in the exit pupil of a microscope to determine the microscope’s three‐dimensional point spread function (PSF) experimentally. The wavefront yields the microscope PSF through a Fourier transform that models propagation of light from the exit pupil to the image plane. A Shack–Hartmann wavefront sensor is used to measure the wavefront shape by recording lateral displacements of a grid of focused spots created by a lenslet array. The displacement of each spot is related to the local wavefront slope. Thus, with appropriate sampling across the exit pupil, the entire wavefront can be reconstructed. This technique does not require the use of a sub‐resolution object to obtain the three‐dimensional microscope PSF. Consequently, larger, brighter fluorescent objects may be imaged, thereby reducing the requirements for detector sensitivity and leading to a three‐fold increase in the axial range over which the PSF is measured. The Shack–Hartmann technique results in a description of the PSF as a continuous function whose sampling is not dependent on the size of the CCD pixels. The Shack–Hartmann sensor is not limited by the numerical aperture of the objective and can easily be calibrated to measure the PSF at any wavelength.
Study of carbon fibres and carbon–carbon composites by scanning thermal microscopy
Authors: Blanco C. , Appleyard S. P. , Rand B.
Published: March 2003

Scanning thermal microscopy (SThM) is a relatively new technique based on atomic force microscopy in which the tip is replaced by an ultra‐miniature temperature probe. This paper reports on a preliminary investigation of the application of SThM in the characterization of the thermal properties of carbon fibres and carbon–carbon (CC) composites. The technique enabled a comparative study to be made of discrete fibre and matrix thermal properties in a series of model unidirectional composites. The thermal images revealed a marked increase in thermal conductivity of the matrix with increasing temperature of treatment and hence confirmed the development of a highly ordered carbon matrix. The results were in qualitative agreement with previously determined values of thermal conductivity from which the separate values of fibre and matrix thermal conductivity had been derived. The technique was also applied to the characterization of samples of unknown processing history, enabling an estimation to be made of the heat treatment and type of the fibres and matrix present in the composite. It was concluded that SThM promises to be a powerful technique for the study of the thermal properties of CC composites and carbon fibres, as it uniquely enables variations in local thermal conductivity to be detected and resolved. Absolute quantification of the technique remains the key to its future widespread acceptance in materials characterization.
Phase evolution in cholesterol/DPPC monolayers: atomic force microscopy and near field scanning optical microscopy studies
Authors: Yuan C. , Johnston L. J.
Published: March 2003

A combination of atomic force microscopy (AFM) and near field scanning optical microscopy has been used to study domain formation in dipalmitoylphosphatidylcholine (DPPC)/cholesterol monolayers with cholesterol concentrations ranging from 0 to 50%. The results show a clear evolution from a mixture of liquid expanded and liquid condensed phases for cholesterol concentrations < 10% to a mixture of liquid expanded and two cholesterol‐containing phases at intermediate concentrations, and finally to a single homogeneous liquid ordered phase for 33% cholesterol. Mixtures of the various phases are clearly identified by height differences in AFM and in some cases by fluorescence imaging for samples containing 0.5% BODIPY dye, which localizes preferentially in the more fluid phase. Note that fluorescence imaging, at least with the dye used here, is unable to distinguish between the cholesterol‐rich and cholesterol‐poor phases detected at intermediate cholesterol concentrations. The combination of fluorescence and AFM imaging provides a more complete picture of the phase evolution for cholesterol/DPPC monolayers than could be obtained by either technique alone, and presents substantial advantages over conventional fluorescence microscopy in that submicrometre‐sized domains can be readily detected.
Functional expression of corticotropin‐releasing hormone (CRH) receptor 1 in cultured rat microglia
Authors: Wang Wei , Ji Ping , Riopelle Richard J. , Dow Kimberly E.
Published: March 2003

Corticotropin‐releasing hormone (CRH), known as a key regulator of the hypothalamic–pituitary–adrenal axis response to stress, elicits its biological effects by binding to two membrane receptors (CRH‐R1 and CRH‐R2). The present studies examined the presence of functional expression of CRH receptors in cultured microglia of rat. CRH‐R1 mRNA and protein were detected by reverse transcriptase polymerase chain reaction (RT‐PCR), western blotting and receptor chemical cross‐linking assay in cultured microglia. CRH‐R2 mRNA was undectable by RT‐PCR. The radioligand binding analysis using [125I]Tyr‐rat/human CRH revealed a high affinity binding site (Kd of 1.2 nm and Bmax of 84 fmol/mg of protein). Competition studies using CRH and related peptides indicated kinetic and pharmacological characteristics consistent with the CRH‐R1 receptor subtype. Receptor chemical cross‐linking assay demonstrated a single band of CRH receptor with a molecular weight of ∼77 kDa, which was inhibited in the presence of excess unlabeled rat/human CRH in a dose‐dependent manner and inhibited by a CRH receptor␣antagonist astressin. Functional coupled cAMP production in cultured microglia was stimulated by exogenous addition of CRH and related peptides in a dose‐dependent manner and blocked by astressin. Our findings suggest the functional expression of CRH‐R1 receptor in rat microglia, indicating an important mechanism of interaction between immune and neuroendocrine systems in brain physiological and␣pathological conditions.
Functional effects of tau gene mutations ΔN296 and N296H
Authors: Yoshida Hirotaka , Crowther R. Anthony , Goedert Michel
Published: March 2003

Mutations in the tau gene cause frontotemporal dementia and parkinsonism linked to chromosome‐17 (FTDP‐17). Functionally, about half of the known mutations increase the alternative mRNA splicing of exon 10 of the tau gene, resulting in the overproduction of tau isoforms with four microtubule‐binding repeats. The other mutations reduce the ability of tau to interact with microtubules, with some mutations also increasing the propensity of tau to assemble into filaments. Here we have examined the functional effects of the recently described tau gene mutations ΔN296 and N296H. Both mutations reduced the ability of tau to promote microtubule assembly, without having a significant effect on tau filament formation. By exon trapping, they increased the splicing of exon 10. ΔN296 and N296H thus define a class of tau mutations with effects at both the RNA and the protein level.
Diabetes‐induced nitrative stress in the retina, and correction by aminoguanidine
Authors: Du Yunpeng , Smith Mark A. , Miller Casey M. , Kern T. S.
Published: March 2003

Aminoguanidine inhibits the development of retinopathy in diabetic animals, but the mechanism remains unclear. Inasmuch as aminoguanidine is a relatively selective inhibitor of the inducible isoform of nitric oxide synthase (iNOS), we have investigated the effects of hyperglycemia on the retinal nitric oxide (NO) pathway in the presence and absence of aminoguanidine. In vivo studies utilized retinas from experimentally diabetic rats treated or without aminoguanidine for 2 months, and in vitro studies used bovine retinal endothelial cells and a transformed retinal glial cell line (rMC‐1) incubated in 5 mm and 25 mm glucose with and without aminoguanidine (100 µg/mL). NO was detected as nitrite and nitrate, and nitrotyrosine and iNOS were detected using immunochemical methods. Retinal homogenates from diabetic animals had greater than normal levels of NO and iNOS (p < 0.05), and nitrotyrosine was greater than normal, especially in one band immunoprecipitated from retinal homogenates. Oral aminoguanidine significantly inhibited all of these increases. Nitrotyrosine was detected immunohistochemically only in the retinal vasculature of non‐diabetic and diabetic animals. Retinal endothelial and rMC‐1 cells cultured in high glucose increased NO and NT, and aminoguanidine inhibited both increases in rMC‐1 cells, but only NT in endothelial cells. Hyperglycemia increases NO production in retinal cells, and aminoguanidine can inhibit this abnormality. Inhibition of diabetic retinopathy by aminoguanidine might be mediated in part by inhibition of sequelae of NO production.
Participation of protease‐activated receptor‐1 in thrombin‐induced microglial activation
Authors: Suo Zhiming , Wu Min , Ameenuddin Syed , Anderson Heidi E. , Zoloty Jamie E. , Citron Bruce A. , Andrade‐Gordon Patricia , Festoff Barry W.
Published: March 2003

Activation of microglia, the resident macrophages in the CNS, plays a significant role in neuronal death or degeneration in a broad spectrum of CNS disorders. Recent studies indicate that nanomolar concentrations of the serine protease, thrombin, can activate microglia in culture. However, in contrast to other neural cells responsive to thrombin, the participation of novel protease‐activated receptors (PARs), such as the prototypic thrombin receptor PAR1, in thrombin‐induced microglial activation was cast in doubt. In this report, by utilizing primary microglial cultures from PAR1 knockout (PAR1–/–) mice, application of the PAR1 active peptide TRAP‐6 (SFLLRN) in comparison to a scrambled peptide (LFLNR), we have unambiguously demonstrated that murine microglia constitutively express PAR1 mRNA that is translated into fully functional protein. Activation of the microglial PAR1 induces a rapid cytosolic free [Ca2+]i increase and transient activation of both p38 and p44/42 mitogen‐activated protein kinases. Moreover, although in part, this PAR1 activation directly contributes to thrombin‐induced microglial proliferation. Furthermore, although not directly inducing tumor necrosis factor‐α (TNF‐α) release, PAR1 activation up‐regulates microglial CD40 expression and potentiates CD40 ligand‐induced TNF‐α production, thus indirectly contributing to microglial activation. Taken together, these results demonstrate an essential role of PAR1 in thrombin‐induced microglial activation. In addition, strategies aimed at blocking thrombin signaling through PAR1 may be therapeutically valuable for diseases associated with cerebral vascular damage and significant inflammation with microglial activation.
Na,K‐ATPase α3 subunit in the goldfish retina during optic nerve regeneration
Authors: Liu Z. W. , Matsukawa T. , Arai K. , Devadas M. , Nakashima H. , Tanaka M. , Mawatari K. , Kato S.
Published: March 2003

The goldfish optic nerve can regenerate after injury. To understand the molecular mechanism of optic nerve regrowth, we identified genes whose expression is specifically up‐regulated during the early stage of optic nerve regeneration. A cDNA library constructed from goldfish retina 5 days after transection was screened by differential hybridization with cDNA probes derived from axotomized or normal retina. Of six cDNA clones isolated, one clone was identified as the␣Na,K‐ATPase catalytic subunit α3 isoform by high‐ sequence homology. In northern hybridization, the expression level of the mRNA was significantly increased at 2 days and peaked at 5–10 days, and then gradually decreased and returned to control level by 45 days after optic nerve transection. Both in situ hybridization and immunohistochemical staining have revealed the location of this transient retinal change after optic nerve transection. The increased expression was observed only in the ganglion cell layer and optic nerve fiber layer at 5–20 days after optic nerve transection. In an explant culture system, neurite outgrowth from the retina 7 days after optic nerve transection was spontaneously promoted. A low concentration of ouabain (50–100 nm) completely blocked the spontaneous neurite outgrowth from the lesioned retina. Together, these data indicate that up‐regulation of the Na,K‐ATPase α3 subunit is involved in the regrowth of ganglion cell axons after axotomy.