bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cerebral palsy births in eastern Denmark, 1987–90: implications for neonatal care
Authors: Topp Monica , Uldall Peter , Greisen Gorm 
Published: March 2003

SummaryThe Cerebral Palsy Register in eastern Denmark has collected cases using a uniform data sampling procedure since birth year 1979. We have investigated changes in the rate of cerebral palsy, related to gestational age, mortality and perinatal risk factors in children born 1983–90. The total cerebral palsy birth prevalence decreased from 3.0 in the birth year period 1983–86 to 2.4 per 1000 live births (P < 0.01) in 1987–90, owing to a decrease among all preterm infants (29–19 per 1000, P < 0.001). The perinatal and early neonatal mortality in preterm infants was unchanged from 1983–86 to 1987–90. The rate of cerebral palsy in term infants was 1.5 per 1000 in all birth‐year periods from 1979–90. Among the cerebral palsy infants, the proportion of very preterm babies treated with mechanical ventilation in the neonatal period decreased from 95% in 1983–86 to 61% in 1987–90 (P < 0.001), while the group treated with CPAP among the moderately preterm babies increased from 61% to 78% (P < 0.05). The significant decline in cerebral palsy rate in preterm infants born 1987–90 may be due to a change in treatment at the neonatal intensive care units using less mechanical ventilation, a hypothesis which needs further investigation.
Childhood leukaemia in Costa Rica, 1981–96
Authors: Monge Patricia , Wesseling Catharina , Rodríguez Ana Cecilia , Cantor Kenneth P. , Weiderpass Elisabete , Reutfors Johan , Ahlbom Anders , Partanen Timo 
Published: March 2003

SummaryChildhood leukaemia incidence in Costa Rica during 1981–96, among the highest in the world, was analysed by histology, gender, birth year, time period of diagnosis, age at diagnosis and region. Numbers of cases were extracted from the database of the National Cancer Registry (RNT) of Costa Rica. Person–years at risk were calculated from census data and post‐census population estimates. During the follow‐up, 918 cases of leukaemia in children under 15 years (510 boys, 408 girls) were reported to the RNT (41% of all childhood malignancies), with an overall age‐standardised incidence rate of 56 per million person–years. Acute lymphocytic leukaemia (ALL) represented 79% and acute non‐lymphocytic leukaemia (ANLL) 16% of the cases, with rates of 43 and 9 per million person–years respectively. There were downward trends in incidence of total leukaemias, ALL and ANLL and ‘not otherwise specified’ (NOS) combined. Incidence of ALL was highest at 1–4 years of age in boys and girls, whereas ANLL peaked in girls during the first year of life. During 1991–96, the decrease in ALL was significant (P = 0.042). A multivariable Poisson regression model identified significant excesses of ALL for boys, for age groups 1–4 and 5–9 years and for three out of seven regions. Possible reasons for the high rates in Costa Rica are discussed.
Socio‐demographic determinants of poor infant outcome in north‐west Russia
Authors: Grjibovski Andrej , Bygren Lars Olov , Svartbo Boo 
Published: March 2003

SummaryThe infant outcome determinants vary in different settings, and there is still a need for analysis within environments. This study was designed to examine the relation between poor infant outcome (PIO), (i.e. any of the following indicators: preterm delivery, low birthweight, perinatal death and low first‐minute Apgar score) and socio‐demographic factors, smoking and alcohol consumption in a Russian setting. The study was conducted in the town of Severodvinsk, north‐west Russia. A total of 1404 pregnant women who attended antenatal care clinics in 1999 and delivered at the municipal maternity home comprised the cohort. Data on women and infants were collected from the medical files and a questionnaire on social indicators, smoking and alcohol consumption was administered. The adjusted odds ratio (OR) calculated by multivariable logistic regression was used as the measure of association between PIO and the variables studied. Education was found to be the most significant factor associated with PIO (OR = 1.9, 95% CI 1.2, 3.0 for secondary or less education compared with at least 3 years of university studies). Increased risks of PIO were also found in mothers aged 30 years and older (OR = 1.6, 95% CI 1.1, 2.5 compared with other age groups) and in unmarried mothers (OR = 1.4, 95% CI 1.0, 1.9) after control for the possible confounders. Other socio‐demographic determinants studied (smoking, alcohol use, stress, maternal occupation, housing and young age of the mother) could not be found to influence PIO. The findings contribute to the hypothesis that maternal education is one of the most important social factors influencing pregnancy outcomes in countries in transition.
Increased mortality in children and adolescents with developmental disabilities
Authors: Decouflé Pierre , Autry Andrew 
Published: March 2003

SummaryA population‐based cohort of 10‐year‐old children with mental retardation, cerebral palsy, epilepsy, hearing impairment or vision impairment, who were ascertained at 10 years of age in a previous study conducted in metro Atlanta during 1985–87, was followed up for mortality and cause of death information. We used the National Death Index to identify all deaths among cohort members during the follow‐up period (1985–95). We estimated expected numbers of deaths on the basis of actual age‐, race‐ and sex‐specific death rates for the entire Georgia population for 1989–91. The objective was to quantify the magnitude of increased mortality and evaluate the contribution of specific disabilities to mortality among children and adolescents with one or more of five developmental disabilities.A total of 30 deaths were observed; 10.1 deaths were expected, yielding an observed‐to‐expected mortality ratio of almost three to one. The numbers of observed deaths exceeded those of expected deaths, regardless of the number of disabilities present, but the ratios were statistically significant (at the 95% confidence level) only in children with three or more co‐existing disabilities. In general, the magnitude of the mortality ratios was directly related to various measures of the severity of the person's disability. An exception to this pattern was the elevated mortality from cardiovascular disease among cohort members with isolated mental retardation (three observed deaths vs. 0.2 expected). The specific underlying causes of death among other deceased cohort members included some that were the putative cause of the developmental disability (e.g. a genetic syndrome) and others that could be considered intercurrent diseases or secondary health conditions (e.g. asthma). Prevention efforts to decrease mortality in adolescents and young adults with developmental disabilities may need to address serious conditions that are secondary to the underlying disability (i.e. infections, asthma, seizures) rather than towards injuries, accidents and poisonings, the primary causes of death for persons in this age group in the general population.
Immunity to experimental neosporosis in pregnant sheep
Authors: Buxton D. , Wright S. , Maley S.W. , Rae A.G. , Lundén A. , Innes E.A. 
Published: March 2003

Neospora caninum is an important cause of fetal loss in cattle but has also infrequently been shown to cause disease in sheep and goats. Experimental infection of pregnant sheep with N. caninum causes clinical and pathological changes very similar to those of neosporosis in cattle. An experiment in sheep was undertaken to examine whether infection with N. caninum before pregnancy conferred immunity to subsequent challenge with the parasite during pregnancy. Primary inoculation of NC1 tachyzoites subcutaneously, either before or during pregnancy, caused a significant temperature response in ewes, while those given a secondary challenge at 90 days gestation (dg) did not show such a response. Primary infection of 12 ewes during pregnancy resulted in the loss of all fetuses while a further 12 ewes inoculated with NC1 tachyzoites before mating and subsequently challenged with the same dose at 90 dg produced nine live and seven dead lambs. There were no fetal deaths in ewes only infected with Neospora before mating although there was serological evidence of vertical transmission in four of their clinically normal offspring while Neospora DNA was detected in the cerebrospinal fluid of a fifth healthy lamb. Thus an experimental primary infection with N. caninum during pregnancy killed all the fetuses while inoculation before pregnancy did not cause any mortality but did provide a degree of protection against subsequent challenge with Neospora during pregnancy.
Susceptibility of the different developmental stages of the asexual (schizogonic) erythrocyte cycle of Plasmodium chabaudi chabaudi to hyperimmune serum, immunoglobulin (Ig)G1, IgG2a and F(ab′)2 fragments
Authors: Cavinato Regiane A. , Bastos Karina R.B. , Sardinha Luiz R. , Elias Rosa M. , Alvarez José M. , D'Império Lima Maria Regina 
Published: March 2003

The mechanisms by which antibodies interfere with Plasmodium growth are still under debate. Characterizing the asexual erythrocyte stages susceptible to antibodies from hyperimmune individuals is therefore a relevant contribution to vaccine research. In this study, using a virulent and synchronous murine malaria parasite, Plasmodium chabaudi chabaudi AJ, we have shown that trophozoites and circulating schizonts are not the main targets for antibodies from hyperimmune serum. In drug‐cured mice challenged with a high inoculum of ring‐infected erythrocytes, parasitemias do not decline until the moment of erythrocyte rupture, suggesting that effector mechanisms operate immediately prior to reinvasion. Confirming these findings, treatment of primary‐infected mice with hyperimmune serum inhibited the generation of new ring forms, but did not alter the numbers of schizont‐infected erythrocytes, despite the fact that these cells were recognized by immunoglobulin (Ig)G antibodies. When these mice were treated with IgG1 or IgG2a purified from hyperimmune serum, both subclasses limited reinvasion, but IgG2a showed a stronger protective activity. The fact that Fc digestion decreases but does not abrogate protection suggests that both Fc‐dependent and independent mechanisms participate in this process. Treatment with cobra venom factor did not interfere with the antibody‐mediated protection, ruling out the participation of the complement system in both lysis and phagocytosis of merozoites or infected erythrocytes. Therefore, in mice suffering from P. c. chabaudi AJ malaria, merozoite neutralization seems to be a major mechanism of protection conferred by hyperimmune serum antibodies. However, FcγR‐mediated interactions, or other mechanisms not yet defined, may also contribute to inhibit erythrocyte reinvasion.
Worms and malaria: noisy nuisances and silent benefits
Authors: Nacher Mathieu 
Published: March 2003

Summary The burden of malaria mortality has been a major evolutionary influence on human immunity. The selection of the most successful immune responses against malaria has been in populations concomitantly infected by intestinal helminths. Animal models have shown that coinfections with helminths and protozoa in the same host elicit a range of antagonist and synergistic interactions. Recent findings suggest similar interactions take place between helminths, Plasmodium falciparum and humans. However, as the threat of HIV and tuberculosis becomes a major selective force, what used to be a successful ecological system may now prove detrimental. Nevertheless, the understanding of the ecological forces at play may expose new intervention targets for malaria control, and give a new perspective on our shortcomings against the deadliest of human parasites.
The role of pre‐ and post‐imaginal experience in the host‐finding and oviposition behaviour of the cabbage moth
Authors: Rojas Julio C. , Wyatt Tristram D. 
Published: March 2003

SummaryThe influence of pre‐ and post‐imaginal experience on the orientation, landing, and oviposition of the female cabbage moth, Mamestra brassicae (L.) (Lepidoptera: Noctuidae) was studied in a wind tunnel. The results of experiments on the influence of pre‐imaginal experience do not support the Hopkins host selection hypothesis because the females’ responses to host plants were not affected by the plant species used for feeding the larvae. The females were initially attracted to and landed on chrysanthemum whether or not they were fed on this plant species. In addition, the oviposition preference for cabbage plants was not changed by the larval feeding regimen. Imaginal experience influenced the females’ subsequent orientation/landing responses: exposure of the females to chrysanthemum plants for 5 min decreased their subsequent responses to this species, but subsequent responses to cabbage were not changed when the females were exposed to cabbage plants. Overnight exposure of females to a chrysanthemum or cabbage plant decreased the subsequent orientation/landing on the same species offered in non‐choice tests. A similar effect was observed in responses to chrysanthemum plants after overnight contact, and possibly to cabbage plants, in the two‐choice tests. Overnight exposure to cabbage or chrysanthemum had no effect on subsequent oviposition: females from both treatments oviposited more often on cabbage.
Changes in desiccation resistance during development in the millipedePolydesmus angustus
Authors: David J. ‐F. , Vannier G. 
Published: March 2003

SummaryWater loss at increasing temperature in dry air (< 5% r.h.) was measured for the eight stadia ofPolydesmus angustusLatzel (Diplopoda, Polydesmida: Polydesmidae). Instantaneous rates of water loss, expressed as percentages of original body water, were calculated at 20, 25 and 30°C. At each temperature, the rate of water loss varied greatly among stadia, decreasing between 15‐ and 18‐fold from stadium I to stadium VII, and then significantly increasing from stadium VII to stadium VIII (adult). In all stadia, the rate of water loss increased with rising temperature, but the temperature effect was much more pronounced in juveniles than in larger stadia. The threshold temperature of heat stupor, which was measured from stadium IV onwards, increased significantly during development, from 35.6°C in stadium IV to 39.5°C in adults. Survival at 20°C and 76% r.h. varied as could be expected from the water loss rates in dry air, survival time increasing from stadium I to stadium VII and then decreasing from stadium VII to the adult stage. The maximum tolerable water loss, estimated for stadia V, VII and adults, did not change significantly among stadia (mean: 47% of the original water content), suggesting that survival times under desiccating conditions depended primarily on the rates of water loss. The relevance of the results in terms of summer survival under natural conditions is discussed, and it is concluded that juvenile mortality could be substantial in the field. This is important for understanding the adaptive value of cohort‐splitting inP. angustus.
Stomatal behaviour, photosynthesis and transpiration under rising CO2
Authors: JARVIS A. J. , MANSFIELD T. A. , DAVIES W. J. 
Published: March 2003

Definitions of the variables used and the units are given in Table 1  The literature reports enormous variation between species in the extent of stomatal responses to rising CO2. This paper attempts to provide a framework within which some of this diversity can be explained. We describe the role of stomata in the short‐term response of leaf gas exchange to increases in ambient CO2 concentration by developing the recently proposed stomatal model of Jarvis & Davies (1998). In this model stomatal conductance is correlated with the functioning of the photosynthetic system so that the effects of increases in CO2 on stomata are experienced through changes in the rate of photosynthesis in a simple and mechanistically transparent way. This model also allows us to consider the effects of evaporative demand and soil moisture availability on stomatal responses to photosynthesis and therefore provides a means of considering these additional sources of variation. We emphasize that the relationship between the rate of photosynthesis and the internal CO2 concentration and also drought will have important effects on the relative gains to be achieved under rising CO2.

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The effects of reduced and elevated CO2 and O2 on the seaweed Lomentaria articulata
Authors: Kübler Janet E. , Johnston Andrew M. , Raven John A. 
Published: March 2003

ABSTRACTWe grew a non‐bicarbonate using red seaweed, Lomentaria articulata (Huds.) Lyngb., in media aerated with four O2 concentrations between 10 and 200% of current ambient [O2] and four CO2 concentrations between 67 and 500% of current ambient [CO2], in a factorial design, to determine the effects of gas composition on growth and physiology. The relative growth rate of L. articulata increased with increasing [CO2] up to 200% of current ambient [CO2] but was unaffected by [O2]. The relative growth enhancement, on a carbon basis, was 52% with a doubling of [CO2] but fell to 23% under 5× ambient [CO2]. Plants collected in winter responded more extremely to [CO2] than did plants collected in the summer, although the overall pattern was the same. Discrimination between stable carbon isotopes (Δ13C) increased with increasing [CO2] as would be expected for diffusive CO2 acquisition. Tissue C and N were inversely related to [CO2]. Growth in terms of biomass appeared to be limited by conversion of photosynthate to new biomass rather than simply by diffusion of CO2, suggesting that non‐bicarbonate‐using macroalgae, such as L. articulata, may not be directly analogous to C3 higher plants in terms of their responses to changing gas composition.
Changes in carbohydrate metabolism and assimilate export in starch‐excess mutants of Arabidopsis
Authors: Zeeman S. C. , Rees T. Ap 
Published: March 2003

ABSTRACTThe aim of this work was to investigate the effects on carbohydrate metabolism of a reduction in the capacity to degrade leaf starch in Arabidopsis. The major roles of leaf starch are to provide carbon for sucrose synthesis, respiration and, in developing leaves, for biosynthesis and growth. Wild‐type plants were compared with plants of a starch‐excess mutant line (sex4) deficient in a chloroplastic isoform of endoamylase. This mutant has a reduced capacity for starch degradation, leading to an imbalance between starch synthesis and degradation and the gradual accretion of starch as the leaves age. During the night the conversion of starch into sucrose in the mutant is impaired; the leaves of the mutant contained less sucrose than those of the wild type and there was less movement of 14C‐label from starch to sucrose in radio‐labelling experiments. Furthermore, the rate of assimilate export to the roots during the night was reduced in the mutant compared with the wild type. During the day however, photosynthetic partitioning was altered in the mutant, with less photosynthate partitioned into starch and more into sugars. Although the sucrose content of the leaves of the mutant was similar to the wild type during the day, the rate of export of sucrose to the roots was increased more than two‐fold. The changes in carbohydrate metabolism in the mutant leaves during the day compensate partly for its reduced capacity to synthesize sucrose from starch during the night.
Contributions of diffusional limitation, photoinhibition and photorespiration to midday depression of photosynthesis in Arisaema heterophyllum in natural high light
Authors: Muraoka Hiroyuki , Tang Yanhong , Terashima Ichiro , Koizumi Hiroshi , Washitani Izumi 
Published: March 2003

ABSTRACTDiurnal changes in photosynthetic gas exchange and chlorophyll fluorescence were measured under full sunlight to reveal diffusional and non‐diffusional limitations to diurnal assimilation in leaves of Arisaema heterophyllum Blume plants grown either in a riparian forest understorey (shade leaves) or in an adjacent deforested open site (sun leaves). Midday depressions of assimilation rate (A) and leaf conductance of water vapour were remarkably deeper in shade leaves than in sun leaves. To evaluate the diffusional (i.e. stomatal and leaf internal) limitation to assimilation, we used an index [1–A/A350], in which A350 is A at a chloroplast CO2 concentration of 350 μmol mol−1. A350 was estimated from the electron transport rate (JT), determined fluorometrically, and the specificity factor of Rubisco (S), determined by gas exchange techniques. In sun leaves under saturating light, the index obtained after the ‘peak’ of diurnal assimilation was 70% greater than that obtained before the ‘peak’, but in shade leaves, it was only 20% greater. The photochemical efficiency of photosystem II (ΔF/Fm′) and thus JT was considerably lower in shade leaves than in sun leaves, especially after the ‘peak’. In shade leaves but not in sun leaves, A at a photosynthetically active photon flux density (PPFD) > 500 μmol m−2 s−1 depended positively on JT throughout the day. Electron flows used by the carboxylation and oxygenation (JO) of RuBP were estimated from A and JT. In sun leaves, the JO/JT ratio was significantly higher after the ‘peak’, but little difference was found in shade leaves. Photorespiratory CO2 efflux in the absence of atmospheric CO2 was about three times higher in sun leaves than in shade leaves. We attribute the midday depression of assimilation in sun leaves to the increased rate of photorespiration caused by stomatal closure, and that in shade leaves to severe photoinhibition. Thus, for sun leaves, increased capacities for photorespiration and non‐photochemical quenching are essential to avoid photoinhibitory damage and to tolerate high leaf temperatures and water stress under excess light. The increased Rubisco content in sun leaves, which has been recognized as raising photosynthetic assimilation capacity, also contributes to increase in the capacity for photorespiration.
Glycinebetaine increases chilling tolerance and reduces chilling‐induced lipid peroxidation in Zea mays L.
Authors: Chen W. P. , Li P. H. , Chen T. H. H. 
Published: March 2003

ABSTRACTChilling tolerance was increased in suspension‐cultured cells and seedlings of maize (Zea mays L. cv ‘Black Mexican Sweet’) grown in media containing glycinebetaine (GB). A triphenyl tetrazolium chloride (TTC) reduction test indicated that after a 7 d chilling period at 4 °C, cells treated with 1 mm GB at 26 °C for 1 d had a survival rate (30%) that was twice as high as that of untreated controls. The addition of 2·5 m
M GB to the culture medium resulted in maximum chilling tolerance (40%). The results of a cell regrowth assay were consistent with viability determined by the TTC method. In suspension‐cultured cells supplemented with various concentrations of GB, accumulation of GB in the cells was proportional to the GB concentration in the medium and was saturated at a concentration of 240 μmol (g DW)−1. The degree of increased chilling tolerance was positively correlated with the level of GB accumulated in the cells. The increased chilling tolerance was time‐dependent; i.e. it was first observed 3 h after treatment and reached a plateau after 14 h. Feeding seedlings with 2·5 m
M GB through the roots also improved their chilling tolerance, as evidenced by the prevention of chlorosis after chilling for 3 d at 4 °C/2 °C. Lipid peroxidation, as expressed by the production of malondialdehyde, was significantly reduced in GB‐treated cells compared with the untreated controls during chilling. These results suggest that increased chilling tolerance may be due, in part, to the reduction of lipid peroxidation of the cell membranes in the presence of GB.