bluuebunny/crossref_metadata_2025 huggingface dataset:
HIV‐related oral disease epidemiology among women: year 2000 update
Authors: Shiboski CH
Published: March 2003

OBJECTIVES: The goals of this literature review were to (1) update a prior review [Shiboski CH (1997) The epidemiology of HIV‐related oral manifestations in women: a review. Oral Dis 3: S18–S27] of studies on the epidemiology of HIV‐related oral manifestations in women prior to the availability of highly active antiretroviral therapy (HAART); (2) explore the effect of HAART on HIV‐related oral disease among women; and (3) explore future research directions with respect to HIV‐related oral disease epidemiology among African women.

METHODS: A computer‐assisted search was conducted to identify studies on the prevalence of oral conditions in HIV‐infected women in relation to immunological markers and HAART [excluding studies reviewed in Shiboski CH (1997) The epidemiology of HIV‐related oral manifestations in women: a review. Oral Dis 3: S18–S27]. Results were summarized and discussed for (1) studies conducted in the developed world prior to and during the era of HAART; and (2) studies conducted in sub‐Saharan Africa.

RESULTS: Candidiasis (OC) is the most common oral lesion among HIV‐infected women, and has been found to be associated with a low CD4 count and a high plasma viral load. Preliminary findings suggest that HAART is associated with a decreasing OC incidence. The few studies identified on HIV‐related oral disease in African women suggest that OC is also a common condition in this setting.

CONCLUSION: Future oral epidemiology research efforts in Africa should focus on the potential role of OC as sentinel marker of HIV infection and disease progression, to improve detection and prevention of selected opportunistic illnesses.
Sialochemistry in juvenile idiopathic arthritis
Authors: Walton AG , Welbury RR , Foster HE , Wright WG , Thomason JM
Published: March 2003

OBJECTIVES: To investigate whether there are any differences in salivary flow rates and saliva composition that may contribute to the reported increase in caries prevalence in patients with juvenile idiopathic arthritis (JIA).

DESIGN: Randomized controlled trial.

SETTING: The sialochemistry of children with JIA has rarely been investigated.

METHODS: Unstimulated and stimulated whole saliva was collected from 17 randomly selected JIA patients and 17 age and sex matched controls. Both samples were analysed for salivary flow rate, pH, calcium and phosphate.

RESULTS: Unstimulated and stimulated JIA saliva flow rates, and the flow rate change from unstimulated to stimulated in JIA saliva were all significantly lower than the controls. There were no significant differences in the pH of unstimulated and stimulated JIA saliva compared with the controls, however, the change in pH (from unstimulated to stimulated) in the study group was significantly greater. The JIA patients had non‐significantly lower levels of both calcium and phosphate ions in the unstimulated and stimulated samples.

CONCLUSIONS: This data would suggest that there is both a reduced resting salivary flow and a reduced response to stimulation in JIA patients, which may contribute to a previously reported higher caries prevalence.
Primary oral tuberculosis: a report of a case diagnosed by polymerase chain reaction
Authors: Rivera H , Correa MF , Castillo‐Castillo S , Nikitakis NG
Published: March 2003

We present a case of primary oral tuberculosis, affecting the maxillary gingiva and causing alveolar bone loss in a 34‐year‐old Colombian female patient. Definitive diagnosis was facilitated by polymerase chain reaction analysis, a useful modern tool for the diagnosis of infectious diseases. The location and clinical presentation of this lesion is unusual and underlines the importance of considering tuberculosis in the differential diagnosis of oral lesions that affect the gingiva and alveolar bone.
The identification and characterization of human Sister-of-Mammalian Grainyhead (SOM) expands the grainyhead-like family of developmental transcription factors
Authors: TING Stephen B. , WILANOWSKI Tomasz , CERRUTI Loretta , ZHAO Lin-Lin , CUNNINGHAM John M. , JANE Stephen M.
Published: March 2003

The Drosophila gene grainyhead is the founding member of a large family of genes encoding developmental transcription factors that are highly conserved from fly to human. The family consists of two main branches, with grainyhead as the ancestral gene for one branch and the recently cloned DrosophilaCP2 as the ancestral gene for the other. We now extend this family with the identification of another novel mammalian member, Sister-of-Mammalian Grainyhead (SOM), which is phylogenetically aligned with grainyhead. SOM is closely related to the other mammalian homologues of grainyhead, including Mammalian Grainyhead (MGR) and Brother-of-MGR, sharing a high degree of sequence identity with these factors in the functional DNA-binding, protein dimerization and activation domains. Protein interaction studies demonstrate that SOM can heterodimerize with MGR and Brother-of-MGR, but not with the more distant members of the family. Like grainyhead, the SOM gene too produces several distinct isoforms with differing functional properties through alternative splicing. The tissue distributions of these isoforms differ and all display highly restricted expression patterns. These findings indicate that SOM, like its family members, may play important roles in mammalian development.
Fos Immunoreactivity in the Diagonal Band and the Perinuclear Zone of the Supraoptic Nucleus after Hypertension and Hypervolaemia in Unanaesthetized Rats
Authors: Cunningham J. T. , Grindstaff R. J. , Grindstaff R. R. , Sullivan M. J.
Published: March 2003

We used Fos immunocytochemistry to study the effects of hypertension and hypervolaemia on neurones in the diagonal band of Broca and the perinuclear zone of the supraoptic nucleus, two nuclei that are both involved in the baroreceptor regulation of vasopressin neurones in the supraoptic nucleus. In addition, we used sino‐aortic denervation to examine the role of arterial baroreceptors in the response to these haemodynamic changes. Sham‐operated and sino‐aortic denervated rats were infused with phenylephrine sufficient to increase blood pressure for 2 h. Control rats were infused with the same volume of isontonic saline. Only Sham sino‐aortic denervated rats showed reflex bradycardia in response to the increased blood pressure. Volume expansion was produced by infusing the rats with isotonic saline equal to 10% of their body weight for 10 min, which significantly increased central venous pressure. In the diagonal band of Broca and the perinuclear zone, the number of Fos‐positive neurones was significantly increased after phenylephrine infusion. Sino‐aortic denervation blocked the significant increase in both regions. After volume expansion, a significant increase in Fos staining was observed only in the perinuclear zone of the supraoptic nucleus. This increase was not blocked by sino‐aortic denervation. Our results indicate that both the diagonal band of Broca and the perinuclear zone of the supraoptic nucleus are activated by stimulating arterial baroreceptors; however, the perinuclear zone of the supraoptic nucleus is stimulated during volume expansion. Furthermore, the activation of perinuclear zone of the supraoptic nucleus after volume expansion is not dependent on intact arterial baroreceptors.
Glial–Neuronal–Endothelial Interactions are Involved in the Control of GnRH Secretion
Authors: Prevot Vincent
Published: March 2003

In recent years compelling evidence has been provided that cell–cell interactions involving non‐neuronal cells, such as glial and endothelial cells, are important in regulating the secretion of GnRH, the neuropeptide that controls both sexual development and adult reproductive function. Modification of the anatomical relationship that exist between GnRH nerve endings and glial cell processes in the external zone of the median eminence modulates the access of GnRH nerve terminals to the portal vasculature during the oestrous cycle. The establishment of direct neuro‐haemal junctions between GnRH neuroendocrine terminals and the portal vasculature on the day of pro‐oestrus may be critical for the transfer of GnRH upon its release into the fenestrated capillaries of the median eminence. Notwithstanding the importance of these plastic rearrangements, glial and endothelial cells also regulate GnRH neuronal function via specific cell–cell signalling molecules. While endothelial cells of the median eminence use nitric oxide to effect this regulatory control, astrocytes employ several growth factors, and in particular those of the EGF family and their erbB receptors to facilitate GnRH release during sexual development. Loss of function of each of these erbB receptors involved in the astroglial control of GnRH secretion leads to delayed sexual development. It is clear that regulation of GnRH secretion by cell–cell communication mechanisms other than transsynaptic inputs is an important component of the central neuroendocrine process controlling mammalian reproduction.
Photoperiod and Androgens Act Independently to Induce Spinal Nucleus of the Bulbocavernosus Neuromuscular Plasticity in the Siberian Hamster, Phodopus sungorus
Authors: Hegstrom C. D. , Jordan C. L. , Breedlove S. M.
Published: March 2003

In the Siberian hamster, Phodopus sungorus, short‐day photoperiods induce the winter phenotype, which in males includes a decrease in the production of androgens and changes in physiology to inhibit reproduction. Motoneurones of the spinal nucleus of the bulbocavernosus (SNB) and their target muscles, the bulbocavernosus and the levator ani, a neuromuscular system involved in male copulation, also display seasonal plasticity in P. sungorus. It is not known whether the plasticity seen in the SNB system of gonadally intact hamsters is due to the effects of photoperiod per se, or to the photoperiod‐induced changes in androgen production. To answer this question, we castrated adult male hamsters from long days and then implanted them with capsules containing either testosterone or blanks. Half of the hamsters from each hormone condition were moved into short photoperiod (8 : 16 h light/dark cycle) while the rest were maintained under long‐day conditions (15 : 9 h light/dark cycle). After 15 weeks, many measures of the SNB system, such as somata size and weight of target muscles, responded only to androgen, not to photoperiod. However, there were effects of photoperiod on the neuromuscular junctions (NMJs) that were independent of androgen status. For example, the number of synaptic zones per NMJ and the area of the NMJs were significantly increased by short days and/or testosterone treatment. The two factors exerted an additive, rather than an interactive, effect on these measures. Another striated muscle, the extensor digitorum longus, which is present in both sexes and plays no specialized role in reproduction, displayed neither an effect of androgen nor of photoperiod on fibre size or NMJ structure. These results suggest that, in addition to androgenic effects on SNB plasticity, there is also an androgen‐independent effect of photoperiod on the SNB neuromuscular system.
Effects of elevated ozone and low light on diurnal and seasonal carbon gain in sugar maple
Authors: Topa M. A. , Vanderklein D. W. , Corbin A.
Published: March 2003

The long‐term interactive effects of ozone and light on whole‐tree carbon balance of sugar maple (Acer saccharumMarsh.) seedlings were examined, with an emphasis on carbon acquisition, foliar partitioning into starch and soluble sugars, and allocation to growth. Sugar maple seedlings were fumigated with ambient, 1·7 × ambient and 3·0 × ambient ozone in open‐top chambers for 3 years under low and high light (15 and 35% full sunlight, respectively). Three years of ozone fumigation reduced the total biomass of seedlings in the low‐ and high‐light treatments by 64 and 41%, respectively, but had no effect on whole‐plant biomass allocation. Ozone had no effect on net photosynthesis until late in the growing season, with low‐light seedlings generally exhibiting more pronounced reductions in photosynthesis. The late‐season reduction in photosynthesis was not due to impaired stomatal function, but was associated more with accelerated senescence or senescence‐like injury. In contrast, the 3·0 × ambient ozone treatment immediately reduced diurnal starch accumulation in leaves by over 50% and increased partitioning of total non‐structural carbohydrates into soluble sugars, suggesting that injury repair processes may be maintaining photosynthesis in late spring and early summer at the expense of storage carbon. The results in the present study indicate that changes in leaf‐level photosynthesis may not accurately predict the growth response of sugar maple to ozone in different light environments. The larger reduction in seedling growth under low‐light conditions suggests that seedlings in gap or closed‐canopy environments are more susceptible to ozone than those in a clearing. Similarly, understanding the effects of tropospheric ozone on net carbon gain of a mature tree will require scaling of leaf‐level responses to heterogeneous light environments, where some leaves may be more susceptible than others.
Direct and indirect effects of elevated CO2 on leaf respiration in a forest ecosystem
Authors: Hamilton J. G. , Thomas R. B. , Delucia E. H.
Published: March 2003

We measured the short‐term direct and long‐term indirect effects of elevated CO2 on leaf dark respiration of loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) in an intact forest ecosystem. Trees were exposed to ambient or ambient + 200 µmol mol−1 atmospheric CO2 using free‐air carbon dioxide enrichment (FACE) technology. After correcting for measurement artefacts, a short‐term 200 µmol mol−1 increase in CO2 reduced leaf respiration by 7–14% for sweetgum and had essentially no effect on loblolly pine. This direct suppression of respiration was independent of the CO2 concentration under which the trees were grown. Growth under elevated CO2 did not appear to have any long‐term indirect effects on leaf maintenance respiration rates or the response of respiration to changes in temperature (Q10, R0). Also, we found no relationship between mass‐based respiration rates and leaf total nitrogen concentrations. Leaf construction costs were unaffected by growth CO2 concentration, although leaf construction respiration decreased at elevated CO2 in both species for leaves at the top of the canopy. We conclude that elevated CO2 has little effect on leaf tissue respiration, and that the influence of elevated CO2 on plant respiratory carbon flux is primarily through increased biomass.
Polyamine metabolism in barley reacting hypersensitively to the powdery mildew fungus Blumeria graminis f. sp. hordei
Authors: Cowley T. , Walters D. R.
Published: March 2003

Polyamine levels and activities of enzymes of polyamine biosynthesis and catabolism were examined in the barley cultivar Delibes (Ml1al + Ml(Ab)) reacting hypersensitively to the powdery mildew fungus, Blumeria graminis f. sp. hordei (race CC220). Levels of free putrescine and spermine and of conjugated forms of putrescine, spermidine and spermine were greatly increased 1–4 d following inoculation of barley with the powdery mildew. These changes in polyamine levels were accompanied by elevated activities of the polyamine biosynthetic enzymes ornithine decarboxylase (ODC), arginine decarboxylase (ADC) and S‐adenosylmethionine decarboxylase (AdoMetDC) and the polyamine catabolic enzymes diamine oxidase (DAO) and polyamine oxidase (PAO). Activities of two enzymes involved in conjugating polyamines to hydroxycinnamic acids, putrescine hydroxycinnamoyl transferase (PHT) and tyramine feruloyl‐CoA transferase (TFT) were also examined and were found to increase significantly 1–4 d after inoculation. The possibility that the increased levels of free spermine, increased polyamine conjugates, and increased DAO and PAO activities are involved in development of the hypersensitive response of Delibes to powdery mildew infection is discussed.
Stomatal and photosynthetic responses of olive (Olea europaea L.) leaves to water deficits
Authors: Moriana A. , Villalobos F. J. , Fereres E.
Published: March 2003

The leaf gas exchange of mature olive trees (Olea europaea L.) was characterized over a wide range of water deficits in the field during 1998, in Cordoba, Spain. Leaf photosynthesis (A) and stomatal conductance (gl) responded diurnally and seasonally to variations in tree water status and evaporative demand. In the absence of water stress, A and gl were generally high during autumn and low in days of high vapour pressure deficits (VPD). Leaf A varied between 0 and 2 µmol m−2 s−1 under severe water deficits that lowered the stem water potential (Ψx) to −8·0 MPa, but recovered rapidly following rehydration. Transpiration efficiency (TE) was curvilinearly related to VPD and not influenced by water deficits except in cases of severe water stress, where low TE values were observed at Ψx below −4 MPa. Three models of leaf conductance were calibrated and validated with the experimental data; two were based on the model proposed by Leuning (L) and the other was derived from the widely used Jarvis (J) model. The L models performed better than the J model in two validation tests. The scatter of the predictions and the limited accuracy of all three models suggest that, in addition to the physiological and environmental variables considered, there are additional endogenous factors influencing the gl of olive leaves.
Habitat use of Tibetan Eared Pheasant Crossoptilon harmani flocks in the non‐breeding season
Authors: Lu Xin , Zheng Guang‐Mei
Published: March 2003

Habitat use by Tibetan Eared Pheasant Crossoptilon harmani flocks in shrub vegetation was investigated in the Lhasa area of Tibet during the non‐breeding season of 1995–1996. Home range composition varied considerably among flocks, but stream belts were consistently used as foraging grounds. Slope direction, altitude and vegetation had little effect on habitat selection. In the absence of supplemental food, core range size was positively correlated with flock size, suggesting that food supplementation could support larger flocks. Flocks regularly roosted on the ground at midday at two or three relatively fixed sites within core ranges. At night they used patches of relatively tall, dense vegetation at the year‐round sites in areas near cliffs or in hollows. The size of the night‐roost site was related to flock size. Our results strongly suggested that both foraging and night‐roosting habitats in the shrub environment are crucial to the birds.
Comparative breeding biology of Hen Harrier and Montagu’s Harrier: an 8‐year study in north‐eastern France
Authors: Millon A. , Bourrioux J.‐L. , Riols C. , Bretagnolle V.
Published: March 2003

Hen and Montagu’s Harriers breed in the same cultivated areas of eastern France. We present data from an extensive study conducted in three adjacent areas where 757 nests of the two harriers were monitored between 1993 and 2000, with the aim of comparing the breeding ecology of these two species and to evaluate their possible future trends. Breeding habitat for harriers consisted nearly exclusively of winter cereals, causing great conservation concern in this intensively farmed region. The Hen Harrier was almost absent from two of the study areas. This species showed significantly larger clutch size and higher breeding success than the Montagu’s Harrier, and an earlier breeding phenology. It was thus less adversely affected by harvesting activities than Montagu’s Harrier. Both species showed a reduced breeding success with increasing laying date. There was a large diet overlap between the two species, possibly leading to competitive interactions. Overall, the Montagu’s Harrier should be considered as the more vulnerable of the two species, necessitating conservation measures, such as protection of nests from early harvesting activities. Nevertheless, to maintain both species in agricultural habitats, farming practices that preserve sufficient food should also be promoted.
Three‐dimensional reconstructions of the Achilles tendon insertion in man
Authors: Milz S. , Rufai A. , Buettner A. , Putz R. , Ralphs J. R. , Benjamin M.
Published: March 2003

The distribution of type II collagen in sagittal sections of the Achilles tendon has been used to reconstruct the three‐dimensional (3D) shape and position of three fibrocartilages (sesamoid, periosteal and enthesis) associated with its insertion. The results showed that there is a close correspondence between the shape and position of the sesamoid and periosteal fibrocartilages – probably because of their functional interdependence. The former protects the tendon from compression during dorsiflexion of the foot, and the latter protects the superior tuberosity of the calcaneus. When the zone of calcified enthesis fibrocartilage and the subchondral bone are mapped in 3D, the reconstructions show that there is a complex pattern of interlocking between pieces of calcified fibrocartilage and bone at the insertion site. We suggest that this is of fundamental importance in anchoring the tendon to the bone, because the manner in which a tendon insertion develops makes it unlikely that many collagen fibres pass across the tissue boundary from tendon to bone. When force is transmitted to the bone from a loaded tendon, it is directed towards the plantar fascia by a series of highly orientated trabeculae that are clearly visible in 3D in thick resin sections.
Simulating spatially and physiologically structured populations
Authors: Gurney William S. C. , Speirs Douglas C. , Wood Simon N. , Clarke Elizabeth D. , Heath Michael R.
Published: March 2003

Population dynamics are frequently the product of a subtle interplay between development and dispersal in an inhomogeneous environment. Simulations of spatially inhomogeneous populations with physiologically distinguishable individuals are a known source of numerical difficulty.

 This paper reports a new and highly efficient algorithm for this problem, whose accuracy we demonstrate by comparison with conventional numerical solutions of one‐dimensional problems.

 As an illustration, we construct a two (space)‐dimensional model of a copepod (Calanus finmarchicus) in the NE Atlantic, and demonstrate that its predictions correspond closely with those of an equivalent Lagrangian ensemble.
Estimating the force of infection;Mycobacterium bovisinfection in feral ferretsMustela furoin New Zealand
Authors: Caley Peter , Hone Jim
Published: March 2003

The force ofMycobacterium bovisinfection (λ) in feral ferretMustela furopopulations in New Zealand was estimated, by fitting candidate models to age‐specific disease‐prevalence data. The candidate models were constructed from a set of a priori hypotheses of howM. bovisinfection is transmitted to ferrets, and model selection used to assess the degree of support for each hypothesis.

The estimated force ofM. bovisinfection ranged between five sites from 0·14 year−1to 5·8 year−1, and was twofold higher in males than in females.

The data most strongly supported the hypothesis that transmission ofM. bovisto ferrets occurs from the ingestion ofM. bovis‐infected material from the age of weaning, as modelled by the force of infection being zero up to the age of weaning, and constant thereafter. Other candidate transmission hypotheses (e.g. mating, suckling, routine social interaction) and combinations thereof were unsupported in comparison, and hence it was concluded that transmission from these postulated mechanisms must be insignificant compared with dietary‐related transmission.

The preferred transmission hypothesis was nearly equally supported regardless of whether disease‐induced mortality was included or not, although omitting disease‐induced mortality resulted in a lower force of infection estimate. The dietary transmission hypothesis (omitting disease‐induced mortality) could be easily represented by a generalized linear model, enabling simple analysis of critical experiments designed to identify the source ofM. bovisinfection in feral ferrets.
The effect of plant species on soil nitrogen mineralization
Authors: Van Der Krift Tanja A. J. , Berendse Frank
Published: March 2003

To ascertain the influence of different plant species on nitrogen (N) cycling, we performed a long‐term garden experiment with six grasses and five dicots with different potential growth rates, that are adapted to habitats with different nutrient supplies. We measuredin situN mineralization and nitrification of the soil under monocultures of each species during the fourth year of the experiment.

 We focused on the effects of the different species on (i) annual net N mineralization; (ii) the seasonal pattern of N mineralization; and (iii) the fraction of the total N mineralization that is nitrified. Our hypothesis was that plant species of nutrient‐rich habitats would enhance the N mineralization compared with species of nutrient‐poor habitats.

 The results demonstrate a strong influence of the species on net N mineralization and net nitrification, both of which fluctuated strongly during the year. Overall, species from high fertility habitats increased N mineralization and nitrification more than species from low fertility habitats. About 90% of the mineralized ammonium was oxidized to nitrate. There was no significant difference in this proportion in the plots of species from nutrient‐rich, moderate and nutrient‐poor habitats.
Nitrogen deposition and forest expansion in the northern Great Plains
Authors: Köchy Martin , Wilson Scott D.
Published: March 2003

Atmospheric nitrogen (N) deposition has become one of the most important agents of vegetation change in densely populated regions. It may also contribute to forest expansion into grasslands at the northern edge of the North American Great Plains.

We measured N deposition and available soil N with ion‐exchange resin over 2 years in six national parks in areas varying in population density and industrialization. N deposition was significantly higher in four parks in densely populated regions than in two remote parks.

Available soil N increased significantly with N deposition across all parks.

We measured N mass and15N abundance (δ15N) in vegetation and soil in two parks: Elk Island, receiving 22 kg N ha−1 year−1, and Jasper, receiving 8 kg N ha−1 year−1. Differences between parks in tissue N concentrations were small, but forest expansion over five decades resulted in the mass of N in vegetation increasing by 74% in Elk Island but by only 26% in Jasper. δ15N in forest vegetation was significantly lower in Elk Island than in Jasper, suggesting that anthropogenic sources contribute significantly to the high rates of N entering that ecosystem.

We determined the rate of forest expansion within parks using six decades of aerial photographs. Parks in aspen parkland and boreal forest showed a strong positive relationship between forest expansion and N deposition. The relationships found between N deposition, available soil N and forest expansion suggest that even comparatively low rates of N deposition may accelerate the expansion of forest into temperate grasslands.
Plant biomass and production and CO2 exchange in an ombrotrophic bog
Authors: Moore Tim R. , Bubier Jill L. , Frolking Steve E. , Lafleur Peter M. , Roulet Nigel T.
Published: March 2003

Above‐ground biomass was measured at bog hummock, bog hollow and poor‐fen sites in Mer Bleue, a large, raised ombrotrophic bog near Ottawa, Ont., Canada. The average above‐ground biomass was 587 g m−2 in the bog, composed mainly of shrubs and Sphagnum capitula. In the poor fen, the average biomass was 317 g m−2, comprising mainly sedges and herbs and Sphagnum capitula. Vascular plant above‐ground biomass was greater where the water table was lower, with a similar but weaker relationship for Sphagnum capitula and vascular leaf biomass.

Below‐ground biomass averaged 2400 g m−2 at the bog hummock site, of which 300 g m−2 was fine roots (< 2 mm diameter), compared with 1400 g m−2 in hollows (fine roots 450 g m−2) and 1200 g m−2 at the poor‐fen site.

Net Ecosystem Exchange (NEE) of CO2 was measured in chambers and used to derive ecosystem respiration and photosynthesis. Under high light flux (PAR of 1500 µmol m−2 s−1), NEE ranged across sites from 0.08 to 0.22 mg m−2 s−1 (a positive value indicates ecosystem uptake) in the spring and summer, but fell to –0.01 to –0.13 mg m−2 s−1 (i.e. a release of CO2) during a late‐summer dry period.

There was a general agreement between a combination of literature estimates of photosynthetic capacity for shrubs and mosses and measured biomass and summer‐time CO2 uptake determined by the eddy covariance technique within a bog footprint (0.40 and 0.35–0.40 mg m−2 s−1, respectively).

Gross photosynthesis was estimated to be about 530 g m−2 year−1, total respiration 460 g m−2 year−1, and export of DOC, DIC and CH4 10 g m−2 year−1, leaving an annual C sequestration rate of 60 g m−2 year−1. Root production and decomposition are important parts of the C budget of the bog. Root C production was estimated to be 161–176 g m−2 year−1, resulting in fractional turnover rates of 0.2 and 1 year−1 for total and fine roots, respectively.
Episodic regeneration at the Nothofagus pumilio alpine timberline in Tierra del Fuego, Chile
Authors: Cuevas Jaime G.
Published: March 2003

The short‐ and long‐term dynamics of Nothofagus pumilio were investigated across an altitudinal gradient in Tierra del Fuego. Declining probability of establishment of individuals with increasing altitude (spatial restriction) is expected to lead to increasingly sporadic recruitment towards the alpine timberline (AT) (temporal restriction). Longevity of adult trees and difficulties in establishment at altitude should result in a static AT.

The number of annual growth buds of seedlings suggests that the species regenerates episodically at all altitudes in cycles of a similar length (7–8 years) to those for seed production. Nevertheless, the seedling density in a year of high regeneration (1996) was considerably higher at lower altitudes than at the AT.

Counting of the growth rings of adult individuals revealed a massive episode of establishment between 1800 and 1850 at all altitudes. There was poor establishment between 1920 and 1980. The age range for the entire population fluctuated between 49 and 377 years in 1996.

Although there is no evidence for more frequent recruitment at lower altitudes, differential regeneration ensures that establishment there is more probable.

Individuals at the AT had an average age of 160 years in 1996, suggesting that the border has indeed remained static for at least a century and a half.

The spatial restriction determines that the AT cannot advance until removal of the temporal restriction allows turnover to occur.
VANQUIS, a system for the interactive semantic content analysis and spatio‐temporal query by content of videos
Authors: Machtynger J. , Shotton D. M.
Published: March 2003

Using the video metadata descriptors and data model defined in the accompanying paper (Shotton, D. M.et al.(2002) A metadata classification schema for semantic content analysis of videos.J. Microsc.205, 33–42), we discuss how analysis of the content of scientific videos, and subsequent query by content of the resulting semantic metadata, can be enhanced by the use of an object‐relational database. We illustrate this by describingVANQUIS, a Web‐based prototypevideoanalysis andqueryinterfacesystemfor the interactive spatio‐temporal analysis and subsequent query by content of videos. UsingVANQUISto generate standard SQL (structured query language) statements that address complex data types stored in an object‐relational database, relationships between characters and events contained within and between videos can be identified, and the appropriate video segments containing these characters and events can be retrieved for viewing. We give examples of analysis and query implementation by usingVANQUISto analyse a biological microscopy video, and discuss the wider potential of this methodology for the analysis and query by content of videos containing more general subject matter.
On the role of electron–ion recombination in low vacuum scanning electron microscopy
Authors: Toth M. , Thiel B. L. , Donald A. M.
Published: March 2003

Here we demonstrate the effects of electron–ion recombination on imaging signals utilized in low vacuum scanning electron microscopes (SEMs). The presented results show that, under normal operating conditions, recombination of ionized gas molecules with secondary electrons (SEs) suppresses a significant fraction of emitted electrons. If the ion flux (and hence the spatial dependence of the SE–ion recombination rate) is laterally inhomogeneous across the imaged region of a specimen, contrast in SE images can be influenced and in some cases (under conditions of high detector field strength and long ionic mean free path) dominated by variations in the recombination rate. Consequently, SE images of features such as topographic asperities can exhibit edge‐darkening, leading to inversion of some topographic contrast. Recognition of the extent and nature of electron–ion recombination is required for a correct understanding of processes occurring in variable pressure SEMs and, subsequently, for models of image formation.
A technique for the examination of polar ice using the scanning electron microscope
Authors: Barnes P. R. F. , Mulvaney R. , Wolff E. W. , Robinson K.
Published: March 2003

The microstructure and location of impurities in polar ice are of great relevance to ice core studies. We describe a reliable method to examine ice in the scanning electron microscope (SEM). Specimens were cut in a cold room and could have their surfaces altered by sublimation either before (pre‐etching) or after (etching) introduction to the cryo‐chamber of the SEM. Pre‐etching was used to smooth surfaces, whilst etching stripped away layers from the specimen surface, aiding the location of particles in situ, and allowing embedded structures to be revealed. X‐ray analysis was used to determine the composition of localized impurities, which in some cases had been concentrated on the surface by etching. Examining uncoated surfaces was found to be advantageous and did not detract from qualitative X‐ray analysis. Imaging uncoated was performed at low accelerating voltages and probe currents to avoid problems of surface charging.
MEK and ERK protect hypoxic cortical neurons via phosphorylation of Bad
Authors: Jin Kunlin , Mao Xiao Ou , Zhu Yonghua , Greenberg David A.
Published: March 2003

We investigated the role of mitogen‐activated protein kinase (MAPK) pathways in hypoxic neuronal injury using primary cultures from murine cerebral cortex. Hypoxia caused the death of ∼50% of neurons at 16 h and ∼65% of neurons at 24 h. This was associated with phospho‐activation of the MAPK/extracellular signal‐regulated kinase (ERK) kinase MEK1/2 and its downstream target ERK1/2, but not p38 MAPK or c‐Jun N‐terminal kinase (JNK), as detected by western blotting. The MEK1/2 inhibitor, PD98059, increased neuronal death in hypoxic cultures, suggesting that MEK1/2 promotes neuronal survival, whereas the p38 inhibitors, SB202190 and SB203580, had no effect. To identify downstream effects of ERK1/2 that might regulate hypoxic neuronal death, we measured hypoxia‐induced phosphorylation of three ERK1/2 targets: the 90‐kDa ribosomal protein S6 kinase (RSK), the transcription factor ELK1, and the pro‐apoptotic Bcl‐2 family protein Bad. We observed increased abundance of inactivated (phospho‐)Bad, but no change in phospho‐RSK or phospho‐ELK1. Moreover, the MEK inhibitor PD98059 reduced phospho‐inactivation of Bad in hypoxic cultures. These findings suggest that a cell‐survival program involving phospho‐activation of MEK1/2 and ERK1/2 and inactivation of Bad is mobilized in hypoxic neurons, and may help to regulate neuronal fate following hypoxic‐ischemic injury.
Regulated trafficking of neurotransmitter transporters: common notes but different melodies
Authors: Robinson Michael B.
Published: March 2003

The activity of biogenic amine and amino acid neurotransmitters is limited by presynaptic and astrocytic Na+‐dependent transport systems. Their functional importance is underscored by the observation that these transporters are the targets of broad classes of psychotherapeutic agents, including antidepressants and stimulants. Early studies suggested that the activity of these transporters can be fine tuned by a number of different signaling pathways. In the past five years, several groups have provided compelling evidence that changing the cell surface availability of these transporters contributes to this fine tuning. This regulated trafficking can result in rapid (within minutes) increases or decreases in the plasma membrane expression of these transporters and is independent of transcriptional or translational control mechanisms. Many of the same signaling molecules, including protein kinase C (PKC), tyrosine kinase, phosphatidylinositol 3‐kinase (P13‐K), and protein phosphatase, regulate the transporters for different neurotransmitters. In addition to these classical receptor activated pathways, transporter substrates also regulate activity and cell surface expression of these transporters. In fact, some of the transporters form complexes with signaling molecules. Given the functional and genetic similarities of these transporters, it is not surprising that the same signaling molecules regulate their trafficking, but except for the molecules, the actual effects on individual transporters are remarkably different. It␣is as if the same musical notes have been rearranged into several different melodies.
Neuronal storage of histamine in the brain and tele‐methylimidazoleacetic acid excretion in portocaval shunted rats
Authors: Fogel W. A. , Michelsen K. A. , Granerus G. , Sasiak K. , Andrzejewski W. , Panula P. , Maslinski C.
Published: March 2003

Rats with portocaval anastomosis (PCA), an animal model of hepatic encephalopathy (HE), have very high brain histamine concentrations. Our previous studies based on a biochemical approach indicated histamine accumulation in the neuronal compartment. In this study, immunohistochemical evidence is presented which further supports the amine localization in histaminergic neurons. These neurons become pathological in appearance with cisternae frequently seen along histaminergic fibres in many brain areas, including the hypothalamus, amygdala, substantia nigra and cerebral cortex. Such formations were not observed in sham‐operated animals. The neuronal deposition is predominant, and unique for histamine. It serves as a mechanism to counterbalance excessive brain neurotransmitter formation evoked by PCA. However, there are other mechanisms. The data provided here show that there is also a significant increase in histamine catabolism in the shunted rats, as reflected by both the higher brain N‐tele‐methylhistamine (t‐MeHA) concentration and urinary excretion of N‐tele‐methylimidazoleacetic acid (t‐MeImAA), a major brain histamine end product. The stomach, in addition to the brain, is a site of enhanced histamine synthesis in portocavally shunted subjects. After gastrectomy or food deprivation to eliminate the contribution of the stomach, shunted rats excrete significantly more t‐MeImAA, implying the role of the CNS. This last finding suggests that under strictly defined conditions, namely in parenterally fed HE patients with abnormal plasma l‐histidine, the measurement of urinary t‐MeImAA might provide valuable information concerning putative brain histaminergic activity.
A role for CO2 and bicarbonate transporters in metabolic exchanges in the brain
Authors: Deitmer Joachim W.
Published: March 2003

Acid‐base transporters are linked to the energy metabolism via the end product of oxidative metabolism, carbon dioxide, together with carbonic anhydrase activity. In a tissue such as the brain, where some cells (neurones) are high‐energy consumers when active, and other cells (astroglial cells) are destined for homeostatic and trophic tasks, transport systems may complement each other and cooperate in order to maintain physiological functions. Here, some aspects of the coupling of metabolite shuttling and acid/base‐dependent transport in neurones and glial cells are discussed.
Differential expression and localization of calmodulin‐dependent phosphodiesterase genes during ontogenesis of chick dorsal root ganglion
Authors: Giorgi Mauro , Giordano Daniela , Rosati Jessica , Tata Ada Maria , Augusti‐Tocco Gabriella
Published: March 2003

The level and characteristics of 3′−5′‐cyclic nucleotide phosphodiesterase (PDE) activity in chick dorsal root ganglion (DRG) extracts of 5‐day posthatching chicken (P5) and E10 and E18 embryos were studied. At all stages, PDE activity is stimulated by calcium and calmodulin. A 5‐fold increase in basal cAMP and cGMP PDE activity is evident from E10 to E18, while from E18 to P5 basal PDE activity remains constant. Ion exchange chromatography elution profile indicates that PDE1 isoforms represent the bulk of the PDE activity present. Inhibition studies were performed in order to distinguish the activity due to PDE1A, B and C. Western blot analysis using anti‐mammalian PDE1A, B and C specific antibodies was also performed. Densitometric analysis of the stained bands reveals that PDE1B and PDE1C display a prominent increase between day 10 and day 18 of development (eight‐ and 3.6 fold, respectively) while a more limited increase (1.6‐ and 1.5‐fold) is observed between E18 and P5; on the other hand PDE1A shows continuously increasing levels throughout development. Immunohistochemical analysis was performed with isoform specific antibodies used for western blot analysis. PDE1A immunoreactivity is found in the cytoplasm and fibers of several neurons differing in size and distributed throughout the ganglion. PDE1B staining is evident on all neurons, however, fibers appear very faintly labelled. All neurons appear stained by PDE1C antibody, although the intensity of immunostaining is always heterogeneous in different neuronal populations: no staining was evident on fibers or in non‐neural cells. The distinct spatial and temporal expression patterns of PDE1 isoforms may indicate their different physiological roles in developing and mature chick DRG.
Characterization of the human ABO gene promoter in erythroid cell lineage
Authors: Hata Y. , Kominato Y. , Yamamoto F.‐I. , Takizawa H.
Published: March 2003

BackgroundThe human ABO blood group system is important in transfusion and organ transplantation. Although the molecular basis of the ABO gene has been established, recent studies have begun to characterize the mechanism of the ABO gene expression.

Materials and MethodsTransient transfection assays were carried out in human erythroleukaemia HEL cells and human gastric cancer KATOIII cells. Electrophoretic mobility shift assays were performed using nuclear extracts derived from both cells.

ResultsOur characterization of the 5′‐upstream sequence of the ABO genes indicated that the region between −117 and +31 is essential to direct expression of a reporter gene in erythroid cells. We show that a sequence located between positions −22 and −14 of the ABO promoter binds a ubiquitous transcription factor Sp1 or Sp1‐like protein(s). Mutation of this site abrogates binding of those factors and reduces the ability of the ABO promoter to function in erythroleukaemia cells and gastric cancer cells.

ConclusionThe expression of the ABO promoter appears to be influenced by the binding of Sp1 or Sp1‐like protein(s) in both erythroid and epithelial cell lineages.
A case‐control study of risk factors associated with human T‐cell lymphotrophic virus type‐I seropositivity in blood donors from Guadeloupe, French West Indies
Authors: Rouet F. , Herrmann‐Storck C. , Courouble G. , Deloumeaux J. , Madani D. , Strobel M.
Published: March 2003

Background and objectives An age‐ and gender‐specific distribution characterizes human T‐cell lymphotrophic virus type‐I (HTLV‐I) seropositivity in Guadeloupe (French West Indies). Further epidemiological studies are required to identify other possible risk factors associated with this retroviral infection.

Materials and methods A nested case‐control study was conducted between 1997 and 1999 among blood donors. A total of 102 HTLV‐I‐positive subjects were matched (at a ratio of 1 : 3) by gender, age (±5 years) and donor status (new or regular) to 306 HTLV‐I‐negative controls. Information was obtained through a questionnaire assessing both environmental and behavioural variables.

Results Factors independently associated with HTLV‐I infection included a low level of education [odds ratio (OR) 6·61, confidence interval (CI) 2·89–15·15], black ethnicity (OR 3·28, CI 1·01–10·65), two or more sex partners in the previous 3 years (OR 2·43, CI 1·16–5·10), early age at first sexual intercourse (0·84 risk reduction per additional year, CI 0·76–0·93), a history of sexually transmitted diseases (OR 2·29, CI 1·0–5·34) and positive Chlamydia serology (OR 1·95, CI 1·03–3·68).

Conclusion These data provide a wide spectrum of features associated with HTLV‐I seropositivity, especially sexual risk factors. It strongly suggests that heterosexual intercourse is an important route of HTLV‐I transmission in Guadeloupe, even among low‐risk populations such as blood donors.
Web‐based collaborative inquiry learning
Authors: Chang K‐E. , Sung Y‐T. , Lee C‐L.
Published: March 2003

Abstract This study proposes a web‐based collaborative inquiry learning system. This system uses the World‐wide web (WWW) as a source of knowledge exploration, and provides exploratory problems to guide students to think and explore. A concept map is used as a tool of anchoring and representing knowledge during inquiry process. In the process of learning, learners are allowed to exchange the evidence they have collected, their personal opinions, and the concept maps that they have built. In order to effectively integrate the inquiry learning, collaborative learning, and concept map in the system, this study proposes a collaborative inquiry learning model and related learning activities. Two studies were constructed based on the collaborative inquiry learning model to investigate students' learning processes in the collaborative inquiry learning on the web.
Current usage of nomenclature for parasitic diseases, with special reference to those involving arthropods
Authors: Ashford R. W.
Published: March 2003

Abstract.Terminological confusion has been aggravated by efforts to develop a standardized nomenclature for parasitic diseases (SNOPAD) arising from the proposal byKassaiet al., 1988) for a standardized nomenclature of animal diseases (SNOAPAD). To restabilize international nomenclature of parasitic diseases it is recommended that, whenever appropriate, names should follow the ‘International Nomenclature of Diseases’ (IND) compiled by the Council for International Organizations for Medical Sciences (CIOMS/WHO, 1987). For diseases not included in IND, familiarity should guide the choice of name: traditional English language names of diseases should be preferred, e.g. ‘malaria’, ‘scabies’ or, for parasitic diseases having no traditional name, the taxonomic name of the causative organism should be applied, e.g. ‘Brugia timorimicrofilaraemia’; ‘Plasmodium malariaeinfection’; ‘Simuliumallergy’ − instead of the generic derivatives proposed by SNOPAD, i.e. brugiosis, plasmodiosis and simuliidosis, respectively. For names of new diseases or those rarely mentioned, the suffix ‐osis would normally take precedence. Generally, the name of choice for any disease in any language should be the vernacular term, with commonest English usage preferred for international communication, and publications should include synonyms in the list of keywords.