Lack of association between maternal antibody and protection of African infants from malaria infection

Maternally derived antibodies are believed to protect infants against infection, but there is little direct evidence for a protective role of passively acquired antibodies against malaria. A longitudinal study of malaria infection in 143 infants was conducted in a region of southern Ghana where Plasmodium falciparum is endemic. Infants born in the high-transmission season were less likely to become infected in the first 20 weeks of life than children born in the low-transmission season. Plasma, obtained at birth, was tested for immunoglobulin G (IgG) and IgG subclasses to P. falciparum schizonts and recombinant circumsporozoite antigen, MSP-1(19), MSP-2, AMA-1, and Pf155 (also called ring-infected erythrocyte surface antigen). Antibody levels at birth were not associated with resistance to malaria infection. On the contrary, antibodies at birth were positively associated with infection, indicating that high levels of maternally derived antibodies represent a marker for intensity of exposure to malaria infection in infants. However, all five children who experienced high-density infections (>100 parasites/microl of blood) were seronegative for MSP-1(19) at the time of infection.

Health risk in agricultural villages practicing wastewater irrigation in central Mexico: perspectives for protection

9,435 individuals participated in a cross-sectional survey in the irrigation districts of the Mezquital Valley (central Mexico). Exposure groups were: 848 households irrigating with untreated wastewater, 544 households irrigating with the effluent from a series of interconnected reservoirs, and 928 households farming with natural rainfall. The unit of analysis was the individual, and the health outcomes included diarrhoeal diseases and Ascaris lumbricoides infection. Water quality was assessed using faecal coliforms (FC) and nematode eggs, as suggested by (WHO, 1989) for the safe use of wastewater in agriculture. Children from households irrigating with untreated wastewater (10(8) FC/100 mL and 135 nematode eggs/L) had a 33% higher risk of diarrhoeal diseases and a fivefold increase in risk of A. lumbricoides infection (OR = 5.71) compared to children from the control group, farming with rainfall. The risk of A. lumbricoides infection in older individuals was even higher (OR = 13.18). The final analysis showed that drinking unboiled water and cultivating vegetables crops were both associated with a higher risk of diarrheal diseases (OR = 1.45 and 2.00); individuals infected with A. lumbricoides infection came mostly from landless households with poorer dwellings and low standards of sanitation (OR = 2.20, 2.23, 1.72 and 1.43, respectively). These results are discussed in the context of health protection measures and policy recommendations.

Theory and practice in sport psychology and motor behaviour needs to be constrained by integrative modelling of brain and behaviour

Because of advances in technology, the non-invasive study of the human brain has enhanced the knowledge base within the neurosciences, resulting in an increased impact on the psychological study of human behaviour. We argue that application of this knowledge base should be considered in theoretical modelling within sport psychology and motor behaviour alongside existing ideas. We propose that interventions founded on current theoretical and empirical understanding in both psychology and the neurosciences may ultimately lead to greater benefits for athletes during practice and performance. As vehicles for exploring the arguments of a greater integration of psychology and neurosciences research, imagery and perception-action within the sport psychology and motor behaviour domains will serve as exemplars. Current neuroscience evidence will be discussed in relation to theoretical developments; the implications for sport scientists will be considered.

Serological prevalence of herpes simplex virus type 2 amongst GUM clinic attenders in a district general hospital setting

Our objective was to determine the seroprevalence of herpes simplex virus (HSV) type 2 infection amongst genitourinary medicine (GUM) clinic attenders at a district general hospital using a commercially available enzyme immunoassay (EIA). In a prospective study, heterosexual patients attending the Department of GUM at Trafford General Hospital attending with a new clinical problem and having a blood sample taken for routine syphilis serology had the same sample tested for HSV type 2 antibodies. The prevalence of HSV type 2 seropositivity amongst participants was 9.9% (24/242) for men and 18.7% (46/246) for women. With respect to undiagnosed, asymptomatic infection the seroprevalence was 8.6% and 17% respectively. For those attenders locally resident the seroprevalence was 10.1% and 17.5% respectively, and undiagnosed, asymptomatic infection 8.5% and 17.1% respectively. Although seroprevalence figures in this study are lower than the only previous report in the UK, these results, nevertheless, show that seropositivity is not confined to large urban centres. Patients attending GUM clinics are likely to have high rates of undiagnosed HSV type 2 infection.

Design and analysis issues in cluster-randomized trials of interventions against infectious diseases

This paper discusses the application of the cluster-randomized trial (CRT) design to evaluate the effectiveness of interventions against infectious diseases. In addition to the usual rationale for this design, there are a number of other advantages that are peculiar to the study of infectious diseases. In particular, CRTs are able to measure the overall effect of an intervention at the population level, capturing both the direct effect of an intervention on an individual's susceptibility to infection, and also the indirect effects due to changes in risks of transmission to other individuals, or to the mass effect or 'herd immunity' resulting from intervening in a large proportion of the population. We briefly review published CRTs of interventions against infectious diseases, most of which have been conducted in the developing countries where such diseases predominate. The focus is on trials in which communities or other large groupings are randomized, and in which impacts on infectious disease incidence or mortality are assessed. We then discuss three issues that are of special relevance to CRTs of infectious diseases. First, issues relating to the definition and size of clusters; secondly, the role of matching or stratification, and the choice of matching factors; and thirdly, the definition of direct and indirect effects of intervention, and methods of assessing these components in a CRT. We conclude by outlining some areas for future research.

The response of providers to capitation payment: a case-study from Thailand

Those designing payment systems for health care in low and middle income countries are increasingly looking to capitation payment, in order to avoid the cost inflation experienced with fee-for-service payment. However, there is virtually no documentation of the experience of introducing capitation payment, or of its effects. This paper draws on several research studies to explore responses by health care providers at both the market and facility level to the introduction of capitation payment, in the context of a new compulsory insurance scheme for workers in Thailand. The paper ends by identifying lessons for both Thailand itself and for other countries.

Antibacterial mesh sling: a prospective outcome analysis

OBJECTIVES

To prospectively assess the outcome results of the Gore-Tex antibacterial mesh sling in women with pelvic prolapse and stress incontinence.

METHODS

Between July 1997 and November 1998, 30 women with stress incontinence and vaginal prolapse underwent vaginal reconstruction with the antibacterial mesh sling. All patients had documented stress incontinence by preoperative urodynamic evaluation. Postoperatively, we conducted an outcome analysis on the basis of the results from a self-reported satisfaction questionnaire, a detailed pelvic examination, a cough stress test, and the Q-tip test. Urodynamic studies were performed on patients with persistent stress incontinence or urge symptoms. Cystoscopy was performed on patients suspected of having urethral erosion.

RESULTS

Complete follow-up was available for all 30 patients. Of the group, 12 (40.0%) of 30 underwent implantation of the antibacterial mesh sling alone and 18 (60.0%) underwent additional prolapse repair. The mean follow-up was 18 months (range 9 to 24); mean age was 58 years (range 29 to 87). Stress incontinence was cured in 28 (93.3%) of 30 patients. De novo urge incontinence developed in 1 (5.2%) of 18 patients; urge symptoms persisted in 5 (41.7%) of 12 patients. The postoperative mean Valsalva Q-tip angle was 15 degrees (range 0 degrees to 25 degrees ). The incidence of urethral obstruction and erosion was zero. The mean postoperative pain score was 3 of 10 (range 0 to 6), and the mean satisfaction score was 9 of 10 (range 7 to 10). The mean time to discharge was 21 hours (range 6 to 29). All 30 women (100%) were willing to undergo surgery again.

CONCLUSIONS

The safety profile of the Gore-Tex antibacterial mesh is better than that of the conventional Gore-Tex sling. When meticulous surgical technique is used, excellent short-term results can be achieved in the correction of female stress incontinence.

Implicit learning differences: a question of developmental level?

A. S. Reber's (1992) proposition that the implicit learning system should demonstrate invariance of intellectual level (IQ) was examined by comparing 20 children with intellectual disability (mean mental age [MA] = approximately 5.8 years) with 20 intellectually gifted children (mean MA = approximately 12.4 years) of similar chronological age (CA; approximately 9.5 years). Implicit learning was assessed using a task involving covariation of 2 incidental cues. Explicit learning was assessed using a task of similar logical structure. Contrary to the IQ-invariance proposition, implicit learning as well as explicit learning varied with intellectual level. A secondary aim was to distinguish the contributions of CA, IQ, and MA to implicit learning. This was done by combining the samples of children in the present study with 2 samples of younger and older children of average ability from a study by M. Maybery, M. Taylor, and A. O'Brien-Malone (1995). Analyses showed that MA is critical to implicit learning.

Osteoporosis therapies--future leads and current clinical trials. 13-14 December 1999, London, UK

This IBC conference focused on research areas most likely to generate novel leads for future osteoporosis therapies. There was particular emphasis placed on inhibitors of bone resorption, including progress in the development of existing compounds, such as raloxifene (Evista; Eli Lilly & Co) and the nitrogen-containing bisphosphonates, as well as insights into novel agents, such as the integrin receptors. It was also generally accepted that the next generation of osteoporosis therapies would target osteoblasts with a view to stimulating bone formation. Potential for developing such novel therapies using genomic approaches was also presented.

Synthesis and evaluation of C-9 modified N-acetylneuraminic acid derivatives as substrates for N-acetylneuraminic acid aldolase

Several C-9 modified N-acetylneuraminic acid derivatives have been synthesised and evaluated as substrates of N-acetylneuraminic acid aldolase. Simple C-9 acyl or ether modified derivatives of N-acetylneuraminic acid were found to be accepted as substrates by the enzyme, albeit being transformed more slowly than Neu5Ac itself. 1H NMR spectroscopy was used to evaluate the extent of the enzyme catalysed transformation of these compounds. Interestingly, the chain-extended Neu5Ac derivative 16 is not a substrate for N-acetylneuraminate lyase and behaves as an inhibitor of the enzyme.

Implicit learning differences: a question of developmental level?

A. S. Reber's (1992) proposition that the implicit learning system should demonstrate invariance of intellectual level (IQ) was examined by comparing 20 children with intellectual disability (mean mental age [MA] = approximately 5.8 years) with 20 intellectually gifted children (mean MA = approximately 12.4 years) of similar chronological age (CA; approximately 9.5 years). Implicit learning was assessed using a task involving covariation of 2 incidental cues. Explicit learning was assessed using a task of similar logical structure. Contrary to the IQ-invariance proposition, implicit learning as well as explicit learning varied with intellectual level. A secondary aim was to distinguish the contributions of CA, IQ, and MA to implicit learning. This was done by combining the samples of children in the present study with 2 samples of younger and older children of average ability from a study by M. Maybery, M. Taylor, and A. O'Brien-Malone (1995). Analyses showed that MA is critical to implicit learning.

Timing a one-handed catch. I. Effects of telestereoscopic viewing

The aim of this study was to examine the role of binocular and monocular information sources in specifying time-to-contact. More specifically, it was investigated whether the timing of the one-handed catch is consistent with a binocular tau-function strategy. Subjects (n=8) were required to time their grasp to catch a ball approaching with a constant spatial trajectory. The ball approached at three different constant velocities (1.5, 2.0 and 2.5 m/s). Vergence and disparity were manipulated through subjects wearing a telestereoscope to increase the effective interocular separation, under both binocular and monocular viewing. Subjects performed 24 trials in each of the four conditions. Subjects' started the opening of the hand earlier in the binocular telestereoscope condition when a ball approached with velocity of 1. 5 m/s. They then closed the hand earlier in the binocular telestereoscope condition at all ball approach velocities. There were no effects of telestereoscope on the timing of hand opening and closing under monocular viewing. This finding suggests the use of the binocular information in timing the grasp. However, there were effects of approach velocity under all conditions of monocular and binocular viewing. Subjects' closed the hand earlier as a function of increasing approach velocity. Together, the effects of the telestereoscope and approach velocity indicate that timing of the one-handed catch is not consistent with the use of a binocular "tau-function" variable. Rather, it is concluded that multiple sources of monocular and binocular information contribute to the regulation of timing.

A pilot study describing local residents' perceptions of asthma and knowledge of asthma care in selected Chicago communities

STUDY OBJECTIVES

To understand inner-city Chicago residents' perception of the prevalence and severity of asthma as well as their knowledge of asthma control and management.

DESIGN

Cross-sectional survey using a random digital telephone dialing method.

SETTINGS

Five inner-city Chicago communities where a high prevalence and mortality of asthma have been recognized.

PARTICIPANTS

All the residents in the selected communities with a residential telephone had an equal opportunity to be surveyed.

MEASUREMENTS AND RESULTS

The unit of measurement was the household. Only one adult member (age 18 or older) in any randomly selected household was interviewed. The survey included questions modified from the Chicago Asthma Surveillance Initiative study. A total of 2,322 phone calls with 527 successful contacts were made over 1,938 distinct phone lines, resulting in a response rate of 175 of 527 calls (33.2%). Seventy-nine of the participants (45.1%) reported that at least one of their family members (including themselves) has asthma. Eight persons (4.6%) reported asthma as one of the top three health concerns in their community. Of the top three health reasons mentioned for children's being absent from school, only seven persons (4%) mentioned asthma. Participants were unlikely to perceive that the problems with access to asthma care and environmental triggers for asthma in their communities were any worse compared with other communities. Participants having family members with diagnosed asthma scored no better when asked general-knowledge questions about asthma or its signs and triggers than those without a family member having asthma.

CONCLUSIONS

The participants' knowledge and beliefs about the seriousness of asthma revealed in this study appeared unlikely to enhance or support compliance with the challenging requirements of the National Asthma Education and Prevention Panel guidelines. The study was conducted with a small sample, and the results should be carefully interpreted.

Manipulating visual informational constraints during practice enhances the acquisition of catching skill in children

Previous motor learning studies examining the effects of practicing to catch one-handed under varying informational constraints on subsequent skill acquisition are equivocal, perhaps due to the use of relatively inexperienced adult participants. Ecological theory predicts that directing the learner's search for information in the perceptual-motor workspace can enhance skill acquisition. This study manipulated visual informational constraints on novice children (ages 9-10 years) learning to catch one-handed. A crossover transfer design was implemented in which one group acted as controls while two other groups practiced either without visual restrictions before transferring to full vision, or vice versa. The data indicated that learners forced to seek additional information sources under restricted viewing conditions demonstrated a greater positive, accumulative residual effect on acquiring a catching skill. The findings contradict current work on the specificity of practice hypothesis and suggest that varying visual informational constraints to encourage exploratory practice may represent a significant pedagogical approach to motor learning in sport.

Stimulation of wound healing by positively charged dextran beads depends upon clustering of beads and cells in close proximity to the wound

We have previously shown that positively charged dextran (DEAE A25) increases wound breaking strength in linear incisions in rats and nonhuman primates at days 10-14 postwounding. In this article, we examined the cellular responses to different types of charged dextran beads (DEAE A50 and Cytodex-1) in culture studies and in rat incisional wounds. We show that Cytodex 1 and DEAE A50 beads also increased wound breaking strength in a rat linear incisional model. However, the increase was approximately 30-40% less than that observed in wounds treated with DEAE A25 beads. The main distinction between the three types of beads was the presence of bead clusters observed in tissue sections. Wounds treated with DEAE A25 beads formed distinct clusters while both Cytodex 1 and DEAE A50 beads clustered to a lesser extent or failed to cluster at all. We propose that the different types of charged dextran beads improve healing by promoting cell adhesion and encouraging proliferation in close proximity to the wound. We also hypothesize that the 30-40% improvement in wound breaking strength seen with DEAE A25 beads compared to other types of charged dextran beads (DEAE A50 and Cytodex-1) originates from the unique characteristic of DEAE A25 beads in forming cell-bead aggregates adjacent to the wounded area. This clustering, in turn, affects the distribution of cells infiltrating the wounded area (such as macrophages) during the healing process and, as a consequence, alters the distribution of matrix molecules and growth factors secreted by these cells.

Newborns develop a Th1-type immune response to Mycobacterium bovis bacillus Calmette-Guérin vaccination

Data obtained in animals indicate that neonatal immune responses are biased toward Th2. This could reduce the efficacy of vaccines against viral and mycobacterial diseases. The ability of human newborns to develop a Th1 immune response upon immunization has not been studied. Since the vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) triggers a Th1-type response in adults, we investigated whether it induces a similar response in newborns and whether age at vaccination influences immunogenicity. We found that BCG vaccination at birth induces a memory Th1-type response of similar magnitude to that when given later in life. This study demonstrates that human newborns can be immunized against pathogens controlled by a Th1 immune response.

Patient satisfaction in Bangkok: the impact of hospital ownership and patient payment status

INTRODUCTION

Patient satisfaction with care received is an important dimension of evaluation that is examined only rarely in developing countries. Evidence about how satisfaction differs according to type of provider or patient payment status is extremely limited.

OBJECTIVE

To (i) compare patient perceptions of quality of inpatient and outpatient care in hospitals of different ownership and (ii) explore how patient payment status affected patient perception of quality.

METHODS

Inpatient and outpatient satisfaction surveys were implemented in nine purposively selected hospitals: three public, three private for-profit and three private non-profit.

RESULTS

Clear and significant differences emerged in patient satisfaction between groups of hospitals with different ownership. Non-profit hospitals were most highly rated for both inpatient and outpatient care. For inpatient care public hospitals had higher levels of satisfaction amongst clientele than private for-profit hospitals. For example 76% of inpatients at public hospitals said they would recommend the facility to others compared with 59% of inpatients at private for-profit hospitals. This pattern was reversed for outpatient care, where public hospitals received lower ratings than private for-profit ones. Patients under the Social Security Scheme, who are paid for on a capitation basis, consistently gave lower ratings to certain aspects of outpatient care than other patients. For inpatient care, patterns by payment status were inconsistent and insignificant.

CONCLUSIONS

The survey confirms, to some extent, the stereotypes about quality of care in hospitals of different ownership. The results on payment status are intriguing but warrant further research.

Expression of p190A during apoptosis in the regressing rat ventral prostate

After hormonal ablation, 90% of the secretory epithelial cells of the prostate undergo apoptosis, and the remaining cells are reorganized as the tissue is remodeled. Using differential display RT-PCR of total RNA extracted from the rat ventral prostate before and 4 days after castration, we have cloned and sequenced a number of complementary DNAs whose cognate messenger RNAs (mRNAs) may be either up- or down-regulated during prostatic regression. One sequence of particular interest, 25.2, is up-regulated after castration and is homologous to p190, a protein associated with cytoskeletal reorganization. RT-PCR has confirmed that the steady state level of p190A mRNA is increased in the rat ventral prostate after castration, and Western blot analysis indicates that the protein levels for p190A also increase. The steady state level of p190B mRNA, the second isoform of p190, does not appear to change significantly after hormone ablation. Immunohistochemical analysis demonstrates that p190A is up-regulated primarily in the columnar epithelial cells that actively undergo cell death after hormone ablation. As Rho-GAP signaling had been shown to be influenced by p190 levels, leading to the disassembly of focal adhesion contacts and the loss of cytoskeletal architecture, we also measured the changes in Rho-GAP during prostate regression. Rho-GAP levels do not change significantly, suggesting that changes in stoichiometry of the interaction between p190A and Rho-GAP may be a prerequisite for the initiation of cytoplasmic condensation. These intracellular events coupled with the proteolytic degradation of the extracellular matrix appear to be integral to the apoptotic process in glandular epithelia.

Elevated expression of FGF-2 does not cause prostate cancer progression in LNCaP cells

BACKGROUND

Androgen-independent (AI) prostate cancer (CaP) resulting from progression of disease is untreatable. Such progression may relate to upregulation and autocrinicity of growth factor expression. We studied one candidate growth factor, basic fibroblast growth factor (FGF-2).

METHODS

LNCaP cells made autocrine for FGF-2 by stable transfection with FGF-2 were examined for cancer progression, measured by 1) altered response to androgen, 2) ability to grow more quickly when cocultured with bone cells in vitro or to form tumors when coinoculated with bone cells in vivo, or 3) increase in metastatic ability.

RESULTS

Stably transfected lines differed in FGF-2 protein expression. LNCaP-HF (high production of FGF-2) expressed more FGF-2 than LNCaP-LF (low production of FGF-2); controls were negative. In vitro, compared with LNCaPs, LNCaP-HF cells showed a slightly increased growth rate, reduced proliferation in response to androgen but not to estrogen or progesterone, and a decreased proliferative response to epidermal growth factor (EGF) and FGF-2. Although giving a slightly faster take rate, LNCaP-HF cells without Matrigel only formed small, fast-regressing tumors in male nude mice, and with Matrigel, did not differ from LNCaPs in growth rate or tumor size. No metastases occurred. No tumors grew in females. Mixed growth of FGF-2 transfectants with human fetal osteoblasts failed to cross-stimulate in vitro, or to allow tumor formation in vivo.

CONCLUSIONS

Although FGF-2 is overexpressed in AI CaPs, our experiments show that upregulation of FGF-2 expression is not sufficient to cause androgen independence, tumorigenicity, or metastases production (i.e., prostate cancer progression) in LNCaP cells.