bluuebunny/crossref_metadata_2025 huggingface dataset:
The biodiversity of Madagascar: one of the world's hottest hotspots on its way out
Authors: Ganzhorn Jörg U. , Lowry Porter P. , Schatz George E. , Sommer Simone
Published: March 2003

Madagascar is renowned not only for its high biodiversity and high degree of endemism, but also for ongoing loss of the original primary vegetation. Here we draw attention to the critical degree of vulnerability of Madagascar's littoral forest, western dry deciduous forest, and evergreen forests of the high plateau. Conservation efforts in these forest formations have been low compared to those in the evergreen rainforest of eastern Madagascar. Due to their fragmented nature these ecosystems urgently require reinforced conservation programmes.
Dramatic declines in saiga antelope populations
Authors: Milner-Gulland E. J. , Kholodova M.V. , Bekenov A. , Bukreeva O. M. , Grachev Iu. A. , Amgalan L. , Lushchekina A. A.
Published: March 2003

We present new data on the size of all the saiga antelope populations; three populations of the subspecies Saiga tatarica tatarica in Kazakhstan, one of S. t. tatarica in Kalmykia, Russia, and two of S. t. mongolica in Mongolia. The data suggest that three populations are under severe threat from poaching and have been declining at an increasing rate for the last 2–3 years. The Ustiurt population in Kazakhstan was relatively secure but is now also under threat. There is evidence of much reduced conception rates in Kalmykia, probably because of selective hunting of adult males. The Mongolian subspecies shows no evidence of recent decline, but is of concern because of the population's small size. The cause of the population declines appears to be poaching for meat and horns, which is a result of economic collapse in the rural areas of Kazakhstan and Kalmykia. We suggest that full aerial surveys be carried out on the Betpak-dala (Kazakhstan) and Mongolian populations, and that funding is urgently required for the control of poaching in all parts of the saiga range.
Range contractions in the Critically Endangered Seychelles terrapins (Pelusiosspp.)
Authors: Gerlach J. , Canning L.
Published: March 2003

The status of the Seychelles endemic terrapins is reviewed based on field-surveys.Pelusios castanoides intergularisandP. subniger parietalisare confined to a small number of marshes and rivers. All the sites occupied are limited in area (<4.5 ha) and under threat from drainage, predation and invasion by alien water plants. The smallest populations are unlikely to be viable in the long-term. Both species can be categorized as Critically Endangered using the IUCN Red List categories, with highly restricted ranges (2.89 and 6.02 ha forP. castanoidesandP. subniger, respectively) that have decreased by over 50 per cent in recent years. Conservation of these species requires both the protection of wetland habitats and the establishment of new populations in protected areas. A captive breeding programme has been established with the aim of reintroducing juveniles into secure reserves. The endemic speciesP. seychellensismay be extinct.
The relationship between congenital cardiovascular malformations and spontaneous abortion in preceding pregnancy
Authors: Sheiner Eyal , Katz Miriam , Fraser Drora , Gohar Josef , Carmi Rivka
Published: March 2003

Previous studies have shown an increased frequency of spontaneous abortions in the pregnancy preceding a fetus or a newborn with neural tube defect (NTD) compared with a normal newborn. One explanation of this observation is the trophoblastic cell rest hypothesis put forward by Knox and Clarke, suggesting a teratogenic interaction between the developing embryo and pathological remnants of a previous pregnancy. The other explanation is that the previously lost fetus was also affected with neural tube defect. The aim of this study was to verify whether this observation is also valid for congenital cardiovascular malformations (CCVM). Demographic and obstetric data of 99 mothers (58 Jewish and 41 Bedouin) of newborns who died in the neonatal period from isolated CCVM were compared with those of 103 mothers (48 Jewish and 55 Bedouin) of newborns who died of congenital defects other than NTD and CCVM. Spontaneous abortions in the preceding pregnancy were found in 32% of the cases with CCVM compared with 14% of cases with other defects (ODs) (P = 0.0012; odds ratio = 3.1, 95% confidence interval 1.5–6.4). This significant difference was independent of maternal age and number of pregnancies or deliveries. No difference was found between Jews and Bedouins. As there is no indication in the literature that fetuses with isolated CCVM tend to be spontaneously aborted, our findings are more supportive of the trophoblastic cell rest theory.
Perinatal events and the risk of intraparenchymal echodensity in very‐low‐birthweight neonates
Authors: O’Shea  , Kothadia  , Roberts  , Dillard
Published: March 2003

A case‐control study was performed to identify perinatal events associated with intraparenchymal echodensity on cranial ultrasonography – an important antecedent of cerebral palsy in very‐low‐birthweight infants. Forty‐eight infants with birthweight < 1500 g and intraparenchymal echodensity on cranial ultrasound examination and 90 controls with normal cranial ultrasounds were identified within a cohort of 1791 consecutive very‐low‐birthweight infants born at a regional obstetric referral centre. Data about potential risk factors were obtained from medical records of cases and controls. Among prenatal factors, chorioamnionitis (odds ratio[OR]: 3.2; 95% confidence interval: 1.3, 8.1) and placental abruption (OR 2.6 [1.0, 6.6]) were associated most strongly with an increased risk of intraparenchymal echodensity and pre‐eclampsia (OR 0.3 [0.1, 0.8]) was associated most strongly with a decreased risk. When controlling for gestational age, multiple gestation was also associated with an increased risk (OR 2.7 [1.0, 7.5]). Neonatal factors independently associated with an increased risk included low systolic blood pressure (< 33 mmHg in the first 12 h of life; odds ratio 8.0 [2.0, 31.3]), receipt of a fluid bolus in the first 12 h of life (OR 19.7 [4.6, 84.3]), need for cardiopulmonary resuscitation in the first 72 h (OR 6.9 [1.5, 31.3]) and pneumothorax in the first 72 h of life (OR 27.0 [4.3, 167.2]). When analyses were restricted to infants who were not given a fluid bolus, the associations with chorioamnionitis and placental abruption were attenuated. When excluding infants who had a pneumothorax, the associations with placental abruption and multiple gestation were attenuated. Restriction of infants with systolic blood pressure < 33 mmHg resulted in attenuation of associations with pre‐eclampsia and multiple gestation. These analyses suggest the possibility that potentially modifiable postnatal events may be involved as intervening factors linking chorioamnionitis, placental abruption and multiple gestation with subsequent intraparenchymal echodensity.
Active and passive smoking during pregnancy and risk of central nervous system tumours in children
Authors: Filippini  , Farinotti  , Ferrarini
Published: March 2003

The effects of maternal active and passive smoking during pregnancy on childhood central nervous system (CNS) tumours were assessed in a population‐based case–control study. The mothers of 244 children aged 0–15 years with CNS tumours and 502 control mothers were interviewed about their smoking habits. All families were resident in the region of Lombardy, Italy. Risk estimates were calculated by unconditional logistic regression, adjusted for age, sex and area of residence. Active smoking by the parents before pregnancy was not associated with increased risk of CNS tumours in the children. Active smoking by the mother during early pregnancy (approximately the first 5 weeks) was associated with a slightly increased risk of the child developing a CNS tumour (odds ratio [OR] 1.5 [95% CI 1.0, 2.3]). An increased risk of CNS tumours was found in the children of non‐smoking mothers exposed regularly to tobacco smoke both in early pregnancy (OR 1.8 [95% CI 1.2, 2.6]) and in late pregnancy (OR 1.7 [95% CI 1.2, 2.5]). Although this study was retrospective, the results confirm our previous findings and suggest an association between the risk of developing CNS tumours in children and regular passive smoking by the mother during pregnancy.
Evaluation of the Dinamap 8100 and Omron M1 blood pressure monitors for use in children
Authors: Barker Mary E. , Shiell Alistair W. , Law Catherine M.
Published: March 2003

The aim of this study was to evaluate the Dinamap 8100 and the Omron M1 (the test devices) against standard criteria for use in children in a fieldwork setting. Device calibration and validation were carried out in accordance with the British Hypertension Society protocol for special groups such as children. A total of 102 children, recruited from infant and junior schools in Southampton, had six sequential measurements made of their blood pressure–four measurements with a mercury sphygmomanometer and two with one of two test devices, 55 children with the Dinamap 8100 and 47 with the Omron M1. Systolic and diastolic readings with the Dinamap 8100 were on average 11 mmHg higher (95% confidence interval [CI]+9, +12 mmHg) and 3 mmHg lower (95% CI −5, −1 mmHg), respectively, than measurements with the mercury sphygmomanometer, overestimating systolic pressures and underestimating diastolic pressures across the whole range observed. The Omron M1 gave readings lower by 1 mmHg on average for systolic pressures and 2 mmHg for diastolic pressures compared with the sphygmomanometer (95% CIs −4, +1 mmHg and −5, +1 mmHg respectively), specifically overestimating higher pressures and underestimating lower pressures. According to the criteria of the British Hypertension Society, neither the Dinamap 8100 nor the Omron M1 can be recommended for use in children in clinical situations in which accuracy of the absolute measurement is required. In epidemiological surveys, in which differences in blood pressure between groups of people are more important than absolute levels, it may be more appropriate to use these devices. Of the two, its more consistent performance supports the Dinamap 8100 as the instrument of choice in such studies of children.
Racial differences in temporal changes in newborn viability and survival by gestational age
Authors: Allen Marilee C. , Alexander Greg R. , Tompkins Mark E. , Hulsey Thomas C.
Published: March 2003

This study examines trends in the rates of very preterm, moderately preterm and gestational age‐specific neonatal mortality, and in the gestational age limit of viability in South Carolina (SC) from 1975 to 1994. We also investigate whether trends were similar between African‐Americans and Whites. We hypothesised that disproportionate reductions in gestational age‐specific mortality, rather than any major changes in the gestational age distributions of either race group, underlie any increasing racial disparity in overall mortality rates. During 1975–94, single livebirths, who were born to mothers resident in SC and were either White or African‐American based on recorded maternal race, were selected for the investigation. We define the gestational age limit of viability as the gestational age at which 50% of infants in the population died within 28 days of life. Although preterm percentages have not improved, there was a marked decline in neonatal mortality. Gestational age‐specific neonatal mortality decreased for both race groups, although there were greater reductions for White preterm infants. By the end of the study period, the African‐American neonatal mortality rate was 2.3 times that of Whites and the gestational age at which 50% of newborns died within 28 days of life was 24.5 weeks for Whites and 23.9 weeks for African‐Americans. The ongoing decline in neonatal mortality continues to be mainly due to reductions in gestational age‐specific neonatal mortality, probably related to high‐risk obstetric and neonatal care. Technological developments in these areas may have differentially benefited Whites, resulting in an increasing racial disparity in neonatal mortality rates. Preterm African‐American infants no longer have a marked survival advantage over White infants, even at the gestational age limit of viability.
Risks of hypertensive disorders in the second pregnancy
Authors: Zhang Jun , Troendle James F. , Levine Richard J.
Published: March 2003

This study examined the incidence of and risk factors for recurrent and newly developed hypertensive disorders in the second pregnancy. We analysed data on 1641 women who had both the first and second pregnancies in the Collaborative Perinatal Project, a large prospective cohort study at 12 hospitals in the US. Nineteen per cent [95% CI 14%, 24%] of women who had gestational hypertension in the first pregnancy, 32% [95% CI 17%, 48%] of those with pre‐eclampsia and 46% [95% CI 32%, 60%] of patients with gestational hypertension or pre‐eclampsia superimposed on chronic hypertension, had recurrent hypertensive disorders in the second pregnancy. Risk factors for recurrence included history of chronic hypertension and thromboembolism, early onset of hypertension in the first pregnancy or persistent hypertension after 5 weeks postpartum and high baseline blood pressure in the second pregnancy. Women with a normotensive first pregnancy but a severe small‐for‐gestational‐age birth had twice the risk of developing hypertension in the second pregnancy (RR = 2.1, 95% CI, 1.1, 4.0). In summary, hypertensive disorders have a 20–50% recurrence rate in the second pregnancy. The earlier the onset of hypertension in the first pregnancy, the higher the overall recurrence rate. Intrauterine growth restriction of the first birth is an independent risk factor for hypertension in the second pregnancy.
Cerebral palsy in Northern Ireland: 1981–93
Authors: Parkes Jackie , Dolk Helen , Hill Nan , Pattenden Sam
Published: March 2003

This paper describes the method of compilation of the Northern Ireland Cerebral Palsy Register (NICPR) and outlines the epidemiology of cerebral palsy (CP) in Northern Ireland in 1981–93 based on an analysis of 784 cases. Multiple and overlapping sources of notification were used to compile the NICPR. Each case was followed up with a standardised assessment completed at age 5 years and validated by a paediatrician. Over 70% of cases were multiply notified, and paediatricians were the most important source of notification. Cases of CP most likely to be under‐ascertained included those very mildly affected, cases who died before the register began (death certificates were searched but found to be unreliable) and cases who moved out of the area before their diagnosis was confirmed. The prevalence of CP for the birth period 1981–93 was 2.24 per 1000 livebirths [95% CI 2.08, 2.40]. There were no statistically significant temporal or geographic variations in the rate of CP. Almost half the cases of CP were of low birthweight (<2500 g), and this proportion increased during 1987–89, but decreased (P< 0.01) more recently (1990–93). The proportion of cases weighing <1000 g trebled from 3% in 1981–83 to 10% in 1990–93 (P< 0.01). The most common CP subtype was bilateral spastic cerebral palsy (55%). Just over a quarter (29%) of cases were unable to walk (with/without aids), and one‐fifth (22%) had no useful hand/arm function. Almost half (49%) the cases had at least one other impairment (intellectual, sensory impairment or active seizures) in association with their CP. Prevalence rates and the pattern of disability in populations of people with CP can only be evaluated on the basis of the methods of case definition and ascertainment. We have demonstrated the methods necessary to ensure valid, standard and detailed information on CP for the purposes of surveillance, service planning and research.
Measuring functional developmental delay in infants and young children: prevalence rates from the NHIS‐D
Authors: Simpson Gloria A. , Colpe Lisa , Greenspan Stanley
Published: March 2003

In order to measure the prevalence of developmental delay among US infants and children, two types of questions were asked of parents in the 1994–95 National Health Interview Survey on Disability (NHIS‐D). To measure functional delay (FD), questions from the Functional Developmental Growth Chart (FDQ), which measures specific age‐appropriate tasks, were used. General delay (GD) was defined using the general type of questions about developmental delay that had been used in previous surveys. Using a nationally representative sample of 15 291 infants and children aged 4–59 months from the NHIS‐D, analyses revealed that, according to these questions, ≈ 3.3% had FD and 3.4% of the children had GD. However, only one‐third of the children were identified by both sets of questions. Thus, two‐thirds of the children identified as having FD were not recognised by their parents as having a delay. Conversely, many parents responded to the GD questions indicating that their child had a delay, but failed to indicate that their child had a functional problem. In addition, only 17% of the children with FD and 31% of those with GD were receiving special services. Multivariable logistic regression analyses found that children with both FD and GD were more likely to be male and to be living in families with incomes below 200% of the poverty level. The findings suggest that the general types of developmental delay questions used in national surveys may not identify children with functional delays. As parents failed to identify these children, it is possible that many of these children may be slipping through paediatric surveillance. Further research to evaluate the use of these measures in population surveys is recommended.
Antenatal mycoplasma infection, the fetal inflammatory response and cerebral white matter damage in very‐low‐birthweight infants
Authors: Dammann Olaf , Allred Elizabeth N. , Genest David R. , Kundsin Ruth B. , Leviton Alan
Published: March 2003

We address the question as to whether Ureaplasma urealyticum or Mycoplasma hominis, cultured from the placenta of very‐low‐birthweight (VLBW) infants, are associated with an increased risk of (a) fetal vasculitis and (b) ultrasonographic cerebral white matter echolucency. The sample consisted of 464 VLBW infants for whom (i) the surface of the chorion was cultured for U. urealyticum and M. hominis; (ii) the placenta was examined histologically; and (iii) a cranial ultrasound scan was obtained close to days 1, 7 or 21. Infants with echolucency were compared with controls in univariable and stratified analyses and in multivariable logistic regressions.

Fifty‐three per cent of placentas from infants with fetal vasculitis harboured U. urealyticum compared with 18% of controls (P ≤ 0.001). M. hominis was present in 14% of cases of fetal vasculitis and in 2% of controls (P ≤ 0.001). Among cases of echolucency, 22% had U. urealyticum compared with 30% of controls (P = 0.33), whereas 17% of these cases and 5% of controls had M. hominis (P = 0.08). Our findings support the hypothesis that U. urealyticum in the placenta of VLBW infants contributes to the fetal inflammatory response without contributing to white matter damage. Our finding that M. hominis in the placenta was associated with a not quite significant threefold risk increase for echolucency deserves further investigation.
Murine Schistosoma bovis infection: analysis of parasitic and immune parameters
Authors: VIANA da COSTA ALEXANDRA , GAUBERT SOPHIE , FONTAINE JOSETTE , LAFITTE SOPHIA , SEIXAS ANTONIO , DE LOURDES SAMPAIO SILVA MARIA , CAPRON ANDRÉ , GRZYCH JEAN‐MARIE
Published: March 2003

Humoral and cellular responses to Schistosoma bovis antigens have been evaluated over a period of 11 weeks in mice exposed to S. bovis cercariae and data analysed in the context of the parasitic parameters (worm and egg loads) recorded at days 30, 60 and 80 of the ongoing infection. Results revealed a decrease of worm burden, particularly marked for female worms, between day 60 and day 80 of infection suggesting a higher susceptibility of female schistosomes to attrition mechanisms. The B‐cell response, studied by measuring the production of different isotypes, was directed against different stage specific antigens, with a predominance of IgG1 antibodies associated with a significant increase of IgA and IgE antibodies after egg deposition. The T‐cell response, assessed after in vitro stimulation of splenocytes, showed a predominant production of Th‐2 cytokines (IL‐4, IL‐5 and IL‐10) occurring after egg laying. Interestingly in contrast to S. mansoni infection the Th‐2 polarization did not seem to be exclusively triggered by egg‐associated antigens since significant amounts of IL‐10 were produced after stimulation with adult worm antigen preparation (SWAP) before the beginning of egg deposition.
Cellular immune responses in cattle experimentally infected withNeospora caninum
Authors: Lundén Anna , Marks Joanne , Maley Stephen W. , Innes Elisabeth A.
Published: March 2003

Neospora caninumhas recently been identified as an important cause of infectious abortion in cattle. The parasite is closely related toToxoplasma gondii, but the two species are antigenically distinct. To examine cell proliferative responses and the induction of IFN‐γ in experimentally infected cattle, four 2–4 months old calves were subcutaneously inoculated withN. caninumtachyzoites. Peripheral blood mononuclear cells were collected regularly and stimulatedin vitrowith a crude lysate ofN. caninumorT. gondiitachyzoites. Significant proliferative responses toN. caninumantigen were recorded in all calves from days 4–6 postinoculation. This response was accompanied by production of high levels of IFN‐γ. Although the calves remained seronegative toT. gondii,while seroconverting toN. caninum, stimulation withT. gondiilysate resulted in cell proliferation of a similar magnitude as that obtained using theN. caninumlysate. However, theT. gondiilysate appeared less effective than theN. caninumlysate to stimulate IFN‐γ production. Cells taken from uninfected control animals did not show any significant proliferation to eitherN. caninumorT. gondiiantigen and no IFN‐γ was produced. These results suggest that the two parasites may possess cross‐reacting T‐cell epitopes, but that the T cells specific forN. caninummay have a different functional capacity. This highlights the need to investigate the antigen specificity and cytokine profile of T cells from infected animals to help understand their role in immunity toN. caninum.
Zinc status in patients with alveolar echinococcosis is related to disease progression
Authors: WELLINGHAUSEN NELE , JÖCHLE WOLFGANG , REUTER STEFAN , FLEGEL WILLY A. , GRÜNERT ADOLF , KERN PETER
Published: March 2003

Zinc is an essential trace element for immune function that plays a role in immune response against parasites. To determine a possible relationship between zinc level and disease status in alveolar echinococcosis (AE), we investigated serum concentrations of zinc, immunoglobulin (Ig)E, IgG, and C‐reactive protein (CRP) in 40 AE patients and 20 controls. Patients were classified into three groups: group A: patients after curative surgery, group B: patients with stabilized disease, group C: patients with progressive disease. Patients showed significantly higher levels of IgE and IgG than controls. Amounts of IgE and IgG were related to disease severity, achieving highest levels in group C and lowest in group A. Zinc levels were comparable in patients and controls. However, there was an obvious association between zinc concentration and disease severity. Zinc was far below the normal range in group C (median 9.2 μmol/l) and significantly diminished compared to group B and controls. An inverse pattern was seen for CRP. In conclusion, lowered zinc concentration in progressive cases may be caused by enhanced immune activation but consumption of zinc by the growing parasite may also play a role. Furthermore, decreased zinc levels may contribute to the observed immunosuppression in AE.
Antibodies against Plasmodium falciparum vaccine candidates in infants in an area of intense and perennial transmission: relationships with clinical malaria and with entomological inoculation rates
Authors: KITUA  , URASSA  , WECHSLER  , SMITH  , VOUNATSOU  , WEISS  , ALONSO  , TANNER
Published: March 2003

Serum immunoglobulin (Ig)G1, IgG3 and total IgG were assessed by immunoabsorbent assay in 198 infants from a Tanzanian village highly endemic for Plasmodium falciparum. Antibodies were measured against epitopes of the circumsporozoite protein (the repetitive epitope (NANP)50 and a construct of the flanking regions (CS27IC)), the malaria vaccine SPf66, and two constructs of the merozoite surface protein‐1 (MSP‐1), a 19‐kDa fragment from the C‐terminal domain (MSP‐119) and an N‐terminal fragment spanning blocks 1–6 (H6‐p190 M‐1/6‐H6). IgG1 and total IgG titres showed similar age profiles, all decreasing for the first 2 months of life. Anti‐(NANP)50 titres remained very low throughout the first year of life, while anti‐CS27IC antibody appeared to peak around 7 months of age. Only a slight tendency to increase with age was observed for levels of the other antibodies studied. IgG3 titres except for H6‐p190(1/6), were very low initially and remained very low throughout the first year of life. Clinical malaria incidence at the village dispensary was analysed prospectively in relation to antibody. No IgG1 or total IgG titre showed protective effects, but low IgG3 against p190(1/6) appeared to be a risk factor in some age groups. Given the large number of antibodies tested, this single indication of possible protection could merely be chance. There were no strong associations between antibody titres and entomologically assessed sporozoite exposure suggesting that transmission‐reducing interventions may have little effect on antibody levels in such children.
Inhibition of nitric oxide production exacerbates chronic ocular toxoplasmosis
Authors: Roberts Fiona , Roberts Craig W. , Ferguson David J.P. , McLeod Rima
Published: March 2003

There is considerable controversy as to the roles of parasite proliferation and the inflammatory response in destruction of the retina during Toxoplasma gondii infection. A murine model was used to investigate the role of nitric oxide in pathogenesis of chronic ocular toxoplasmosis. Increased quantities of messenger RNA (mRNA) transcripts for iNOS were detected in the eyes of chronically infected C57BL/6 mice compared with noninfected control mice. Inhibition of nitric oxide (NO) by the addition of Lω‐nitro‐
l‐arginine methyl ester (
l‐NAME) to the drinking water of infected mice between weeks 4–6 of infection, exacerbated ocular inflammation. The amount of inflammation was assessed semiquantitatively in histological sections of the eye. Eyes from
l‐NAME treated mice showed a significant increase in inflammation of the retina (P = 0.02), choroid (P = 0.03), and vitreous (P = 0.02) compared with control mice. These results demonstrate a protective role for NO in the control of chronic, ocular toxoplasmosis.
Parasite‐secreted products regulate the host response to larval Taenia crassiceps
Authors: Spolski  , Corson  , Thomas  , Kuhn
Published: March 2003

Parasite‐induced immunosuppression is believed to play a significant role in the pathology of cysticercosis, a disease caused by the larval stage of cestode parasites. The biochemical basis for immunoregulation by Taenia crassiceps in experimental cysicercosis is unknown. In order to determine whether or not excretory/secretory (E/S) products from the parasite have the ability to regulate host immune function, the activity of these products was examined. Excretory/secretory products from larvae early in the infection were found to suppress T cell proliferative responses in vitro as well as the production of IFN‐γ and IL‐4. In contrast, E/S products secreted from larvae harvested late in infection were not suppressive. Electrophoretic analysis of E/S products revealed both qualitative and quantitative differences in the pattern of proteins produced by larvae taken from an early infection versus those taken from a chronic infection. The viability of parasites taken from an early infection was greatly reduced compared to those taken from chronically infected mice, suggesting a change in the nature of the host immune response to the parasite during the course of the infection. The proliferative activity and cytokine profiles of host immune cells were examined. Both mesenteric lymph node cells and peritoneal exudate cells were found to produce high levels of both IFN‐γ and IL‐4, consistent with the high levels of these cytokines in sera of chronically infected animals. Chronic infection with Taenia crassiceps therefore is characterized by high levels of production of both Th1 and Th2 cytokines by host cells.
Characterization of a differential immunoscreen epitope of Plasmodium falciparum using combinatorial agents
Authors: Singh Nevil J. , Sehgal Alfica , Sharma Shobhona
Published: March 2003

A differential serological screening of a λgt11 cDNA expression library has identified several clones, which react exclusively to sera samples from persons clinically immune to malaria but not to acute malaria patient sera. One such clone, IPf9, has a 315‐bp cDNA insert, which was found to be conserved in different strains of the human and rodent malarial parasite Plasmodium falciparum and Plasmodium berghei, respectively. The induced expression product of IPf9 was used to generate polyclonal sera in rabbits. The IPf9 expression product was also screened with phage surface display combinatorial libraries to isolate reagents that specifically bound to the IPf9 product. The polyclonal antisera and the combinatorial reagents recognized a 50‐kDa protein from P. falciparum, and a 53‐kDa product from P. berghei. Immunofluorescence studies using asexual and sexual stages of P. falciparum showed the protein to be present within the parasite in each of the asexual and sexual stages. The combinatorial reagents showed a partial inhibition in the growth of P. falciparum in vitro. Mice infected with the P. berghei showed the presence of T‐cells that exhibited lymphoproliferation when stimulated with the IPf9 protein. It is suggested that IPf9 protein is a conserved protein epitope, and may be relevant for a protective immune response to malaria.
Transmission intensity and the immunoepidemiology of bancroftian filariasis in East Africa
Authors: Michael E. , Simonsen P.E. , Malecela M. , Jaoko W.G. , Pedersen E.M. , Mukoko D. , Rwegoshora R.T. , Meyrowitsch D.W.
Published: March 2003

Previous attempts to determine the interactions between filariasis transmission intensity, infection and chronic disease have been limited by a lack of a theoretical framework that allows the explicit examination of mechanisms that may link these variables at the community level. Here, we show how deterministic mathematical models, in conjunction with analyses of standardized field data from communities with varying parasite transmission intensities, can provide a particularly powerful framework for investigating this topic. These models were based on adult worm population dynamics, worm initiated chronic disease and two major forms of acquired immunity (larval‐ versus adult‐worm generated) explicitly linked to community transmission intensity as measured by the Annual Transmission Potential (ATP). They were then fitted to data from low, moderate and moderately high transmission communities from East Africa to determine the mechanistic relationships between transmission, infection and observed filarial morbidity. The results indicate a profound effect of transmission intensity on patent infection and chronic disease, and on the generation and impact of immunity on these variables. For infection, the analysis indicates that in areas of higher parasite transmission, community‐specific microfilarial rates may increase proportionately with transmission intensity until moderated by the generation of herd immunity. This supports recent suggestions that acquired immunity in filariasis is transmission driven and may be significant only in areas of high transmission. In East Africa, this transmission threshold is likely to be higher than an ATP of at least 100. A new finding from the analysis of the disease data is that per capita worm pathogenicity could increase with transmission intensity such that the prevalences of both hydrocele and lymphoedema, even without immunopathological involvement, may increase disproportionately with transmission intensity. For lymphoedema, this rise may be further accelerated with the onset of immunopathology. An intriguing finding is that there may be at least two types of immunity operating in filariasis: one implicated in anti‐infection immunity and generated by past experience of adult worms, the other involved in immune‐mediated pathology and based on cumulative experience of infective larvae. If confirmed, these findings have important implications for the new global initiative to achieve control of this disease.
Anti‐interleukin‐8 activity of tick salivary gland extracts
Authors: Hajnická Valeria , Kocáková Paula , Sláviková Monika , Slovák Mirko , Gašperík Juraj , Fuchsberger Norbert , Nuttall Patricia A.
Published: March 2003

Interleukin‐8 (IL‐8) is one of many mammalian chemokines (chemotactic cytokines) that direct mammalian inflammatory and immune cells to sites of injury and infection. Chemokines are produced locally and act on leucocytes through selective receptors. The principal role of IL‐8 is to control the movement and activity of neutrophils. To date, several tick species have been shown to modulate the production or activity of certain cytokines but none of these are chemokines. Using an IL‐8 specific ELISA, we showed that salivary gland extracts (SGE) from several ixodid tick species (Dermacentor reticulatus, Amblyomma variegatum, Rhipicephalus appendiculatus, Haemaphysalis inermis and Ixodes ricinus) reduced the level of detectable IL‐8. Analyses of fractionated SGE revealed one similar peak of activity for D. reticulatus, A. variegatum and R. appendiculatus; a second peak, observed for D. reticulatus and A. variegatum, differed between the two species. Using radiolabelled IL‐8, SGE and peak activity fractions of D. reticulatus were shown to bind the chemokine, and to inhibit binding of IL‐8 to its receptors on human granuolocytes enriched for neutrophils. The biological significance of these observations was demonstrated by the ability of SGE to inhibit IL‐8 induced chemotaxis of human blood granulocytes. Future isolation and characterization of the active molecules will enable determination of their functional roles in bloodfeeding and effect on tick‐borne pathogen transmission.
Antibody‐dependent cell‐mediated cytotoxicity to newly excysted juvenile Fasciola hepatica in vitro is mediated by reactive nitrogen intermediates
Authors: Piedrafita D. , Parsons J.C. , Sandeman R.M. , Wood P.R. , Estuningsih S.E. , Partoutomo S. , Spithill T.W.
Published: March 2003

Passive intraperitoneal transfer of sera from Fasciola hepatica‐infected sheep, cattle or rats can protect naive rats from F. hepatica infection, suggesting a parasite killing mechanism within the peritoneal cavity that is dependent on the presence of parasite‐specific antibody. We investigated antibody‐dependent cell‐mediated cytotoxicity by resident peritoneal lavage cell populations, containing large numbers of monocytes/macrophages, as a potential host resistance mechanism by which juvenile flukes could be killed within the peritoneal cavity of naive rats. Comparative studies were conducted using cell populations containing large numbers of monocytes/macrophages from sheep. The results demonstrate that monocyte/macrophage‐rich lavage cell populations from rat and sheep differ substantially in their ability to generate nitric oxide . Only resident rat peritoneal lavage cells were able to mediate antibody‐dependent cell‐mediated cytotoxicity against newly excysted juvenile liver fluke. The mechanism of cytotoxicity was dependent on, and directly proportional to, the production of nitric oxide and required attachment of effector cells to the newly excysted juvenile liver fluke tegument, which occurred following the addition of sera from F. hepatica‐infected animals. This is the first report demonstrating a mechanism of cell‐mediated cytotoxicity to newly excysted juvenile liver fluke.
HTLV‐1 decreases Th2 type of immune response in patients with strongyloidiasis
Authors: Porto Aurélia F. , Neva Franklin A. , Bittencourt Helito , Lisboa Waldir , Thompson Robert , Alcântara Luís , Carvalho Edgar M.
Published: March 2003

Eosinophils, immunoglobilin (Ig)E and cytokines have important roles in defence mechanisms against helminths. In this study, the influence of HTLV‐1 infection, characterized by a Th1 type of immune response, was evaluated on the cytokine pattern and parasitic specific IgE response in patients with strongyloidiasis. Patients were divided into four groups: strongyloidiasis without HTLV‐1 infection, strongyloidiasis with HTLV‐1, HTLV‐1 without strongyloidiasis and controls without either helminth infection or HTLV‐1. The cytokine profile was determined in supernatants of mononuclear cells stimulated with Strongyloides stercoralis crude antigen and the parasite specific IgE was measured by ELISA. Patients coinfected with HTLV‐1 had higher levels of interfron (IFN)‐γ and interleukin (IL)‐10 (P < 0·05) and lower levels of IL‐5 and IgE (P < 0·05) than patients with strongyloidiasis without HTLV‐1. There was an inverse relationship between IFN‐γ and IL‐5 (P = 0·01; rs = − 0·37) and between IFN‐γ and parasite specific IgE (P = 0·01; rs = − 0·39), and a direct relationship between IFN‐γ and IL‐10 (P = 0·04; rs = 0·35). These data show that coinfection with HTLV‐1 decreases IL‐5 and IgE responses in patients with strongyloidiasis consistent with a relative switch from Th2 to Th1 response. Immunological responses such as these are important in the control of this helminthic infection.
Wing development in parasitized male and female Sitobion fragariae
Authors: CHRISTIANSEN‐WENIGER PETRA , HARDIE JIM
Published: March 2003

Abstract.Different stages of presumptive winged morphs (males, gynoparae and alate virginoparae) of the blackberry‐cereal aphid, Sitobion fragariae, were exposed to attack by Aphidius ervi. Even though the mechanism influencing wing development in the three aphid morphs differs, the effects of parasitism were similar. Alatiform structures were completely inhibited in all three morphs when the initial attack took place in their first or early second stadium. The disruption of wing development also resulted in apterous/alate‐intermediate forms when aphids were attacked from first (males and gynoparae) or early second (alate virginoparae) up to the fourth larval stadium. The fact that wing development was still disrupted when aphids with well developed wingbuds were parasitized indicates that the early stages of parasitization were influential. Thus, the morphogenetic effects may be exerted by the parasitoid egg or calyx fluid.
Effect of constant light on male sterility in the cotton leafworm Spodoptera littoralis
Authors: Bębas P. , Cymborowski B.
Published: March 2003

Females of the cotton leafworm (Spodoptera littoralis) reared in long day conditions (LD 16:8 h) and mated to males kept throughout the whole period of development in continuous light (LL) oviposit very small numbers of mostly sterile eggs. It was found that in control males reared from the first larval instar in long day conditions there was a large accumulation of euperene sperm bundles in their testes on day 1 after imaginal moult. On day 10 of adult life the number of the sperm bundles was very small. In males kept from the first instar in continuous light there was also high number of sperm bundles on day 1 after imaginal moult but it did not decrease significantly on day 10 as was observed in controls. Transfer of different developmental stages of S. littoralis from long day conditions to continuous light resulted in a big difference in the density of eupyrene sperm bundles in their testes. In control insects reared through the whole of their development in long day conditions there was a significant decrease in the density of eupyrene sperm bundles on day 10 of adult life. By contrast, in males in continuous light, regardless of their developmental stage when transferred, there was either no change in density of sperm bundles in day 10 adults or there was a significant increase in comparison with day 1 adults. The highest density of eupyrene sperm bundles was observed in day 10 adults when they were transferred to continuous light shortly before moulting to the last instar (as day 4 larvae in the last stadium or day 1 pupae). Generally, the density of eupyrene sperm bundles on day 10 of adult development was about 2–2.5 times higher in males in continuous light then those under long day conditions. The results presented here indicate that the last larval instar and the pupa are the stages most sensitive to constant light treatment, which greatly reduces the amount of eupyrene sperm bundles released from the testes.
The major carotenoid pigments of the grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae)
Authors: Jenkins R. L. , Loxdale H. D. , Brookes C. P. , Dixon A. F. G.
Published: March 2003

The economically important grain aphid, Sitobion avenae (F.) shows colour polymorphism, with brown and green forms predominating. Colour is determined both genetically and in response to environmental factors, including nutrition. The biological significance of the colour polymorphism is unknown, although seasonal changes occur in the frequency of colour morphs in the field, whilst the brown morph may have adaptive significance in terms of hymenopterous endoparasitism. The ground colour of aphids is produced by haemolymph pigments, aphins (glucosides) and carotenoids. The latter may be under the synthetic control of intracellular endosymbiotic bacteria. In this study, the major carotenoid pigments of a brown and a green clone of S. avenae were examined using thin layer chromatography (TLC) and high‐performance liquid chromatography (HPLC), and their absorbance spectra recorded. Using TLC, the brown clone produced five bands of different Rf, ranging from yellow, to orange‐pink to pink in colour. In contrast, the green clone gave only a single yellow band of higher Rf than any of the bands of brown aphids. Following separation of carotenoids by HPLC, brown aphids gave seven peaks and green aphids five. Comparison of absorbance maxima with known published values for carotenoids provides strong evidence for the identification of four of the carotenoid pigments from brown aphids (RB‐4, 3,4‐didehydrolycopene; RB‐5, torulene; RB‐6; lycopene; RB‐7, γ‐carotene) and one from green aphids (RG‐2, α‐carotene). The other carotenoids remain unidentified. The biosynthesis and possible biological relevance of the various pigments of S. avenae are briefly discussed.
Spatial and temporal structures of pheromone plumes in fields and forests
Authors: Murlis John , Willis Mark A. , Cardé Ring T.
Published: March 2003

Wind‐borne odour stimuli from a small point‐source of pheromone are intermittent owing to the effects of atmospheric turbulence on the odour plume. The work reported here measures the characteristics of the intermittent stimulus in open fields and forests during typical daytime atmospheric conditions. To model the pheromone plume, negatively charged atmospheric ions were used as a tracer. They were released from an ion generator, and ion detectors measured the fluctuating flux of ions at positions up to 20 m downwind in the open field case and 10 m in the forest. In both the open field and in the forest, ion signals were highly intermittent, with a signal present only 20% of the time. Ion signals recorded in the forest consisted of bursts with gaps between them of at least three‐fold greater duration than those from the open field. In both environments, bursts generally each comprised a series of ‘spikes’, on average three in the field and seven in the forest. To validate the use of ionized air plumes as models of pheromone plumes, the antennae of male Lymantria dispar (gypsy moth) were used as detectors to quantify the plume of synthetic (+)‐disparlure emanating from a 2000 ng point source placed ≈ 10 cm from the ion source. A comparison of ion signals and EAGs (electronantennograms) suggests that the antennae respond to the main spikes within a burst, but no consistent relationship between the strength of the spikes and the magnitude of the EAG response was found. The average strengths of bursts in the ion detector signal decreased systematically as the distance from the ion generator to the ion detector increased. A similar trend, however, was not detected in the EAG response.
Temperature related effects on embryonic development of the Mediterranean locust, Dociostaurus maroccanus
Authors: Quesada‐Moraga E. , Santiago‐Álvarez C.
Published: March 2003

Laboratory studies were conducted to assess the effect of temperature on the development of the eggs of Dociostaurus maroccanus (Thunberg) (Orthoptera, Acrididae) during anatrepsis (stages I–XIV) and during catatrepsis (stages XV–XX). The developmental rates of anatrepsis were studied at five constant temperatures ranging from 10 to 30°C. Egg development occurred over the entire range but at 10°C the embryos were unable to complete anatrepsis. The relationship between temperature and developmental times for completing anatrepsis was analysed by the non‐linear Logan type III model. The optimal temperature estimated for the development of eggs during anatrepsis was 24.7°C; the lower and upper thermal thresholds were 9°C and 31°C, respectively. Once the embryos completed anatrepsis, only those incubated at 15°C continued morphogenesis beyond stage XIV (diapause stage) without a low‐temperature exposure period. The developmental rate of catatrepsis was studied at four constant temperatures ranging from 15°C to 30°C after exposure to low‐temperature, 10°C, for 30, 60 or 90 days. For catatrepsis, temperature and developmental time were linearly and inversely related. Linear regression was used to estimate the lower developmental threshold and the degree days requirements for catatrepsis. Both decreased with longer exposure to the low temperature; the former from 13.8°C to 10.5°C and the latter from 212.8 to 171.5 degree days, following 30 and 90 days at 10°C, respectively. Our results improve the ability of decision support systems for Mediterranean locust pest management by providing better forecasts to land managers and pest advisors.
A microdialysis study of allatostatin degradation in Blattella germanica (L.) (Dictyoptera, Blattellidae)
Authors: Peralta Enrique , Vilaplana Lluïsa , Pascual Nuria , Carreño Cristina , Piulachs Maria‐Dolors , Andreu David , Bellés Xavier
Published: March 2003

Allatostatins with a typical C‐terminal sequence YXFGL‐NH2 are insect neuropeptides with inhibitory properties upon Juvenile Hormone production in the corpora allata, vitellogenin release by the fat body, and gut and dorsal vessel motility. All these biological effects are rapidly reversible, suggesting the occurrence of effective mechanisms for inactivation of the peptides. We have studied the degradation of DRLYSFGL‐NH2 (BLAST‐2), one of the allatostatins of Blattella germanica, in the internal milieu of adult females of this cockroach. The experimental approach combined the use of the radioiodinated derivative [125I‐Tyr4]BLAST‐2, microdialysis techniques and HPLC analysis with a radioisotope detector. Under these experimental conditions, the half‐life of BLAST‐2 in the internal milieu of the adult female of B. germanica was between 3 and 6 min. Such a short half‐life explains the high doses of allatostatins required to obtain the expected biological effects when tested in vivo, and suggests that circulating allatostatins are subject to rapid rates of synthesis and degradation in order to be operative physiologically.