Distribution of the mylohyoid nerve: anatomical variability and clinical implications

The mylohyoid nerve is a branch of the mandibular division of the trigeminal nerve that provides motor supply to the mylohyoid and digastric muscles. Accessory innervation to the pulps of both anterior and posterior mandibular teeth by the sensory component of this nerve has been proposed to be one possible anatomical variation leading to failure of an inferior alveolar nerve block. The aim of this study was to trace the path of the mylohyoid nerve, from its origin in the infratemporal region to its terminal branches, in six human cadavers. Dissections of sagittally-sectioned heads were performed using both medial and submandibular approaches. The anatomy of the mylohyoid nerve was variable in terms of its level of branching, course through the mylohyoid groove or canal, branch numbers to the mylohyoid and digastric muscles, and terminal branching in the submental region. In all cases the mylohyoid nerve was seen to pass down the medial surface of the ramus behind the sphenomandibular ligament.

Clinical features in women with polycystic ovaries: relationships to insulin sensitivity, insulin gene VNTR and birth weight

OBJECTIVE

Polycystic ovaries are a common ultrasound finding, yet few of these women have many clinical features of polycystic ovary syndrome. Clinical presentation may relate to degree of insulin resistance, common polymorphism at the insulin gene VNTR, and birth weight. We therefore examined the relationship between insulin sensitivity, insulin gene VNTR genotype, birth weight and presence of polycystic ovaries/features of polycystic ovary syndrome in a normal population study.

DESIGN AND PATIENTS

In 224 young women recruited as normal volunteers, ovarian morphology was determined by transabdominal ultrasound and features of polycystic ovary syndrome were identified on clinical and biochemical examination. Insulin sensitivity was estimated from fasting glucose and insulin levels using the homeostasis model. Insulin gene VNTR genotypes were determined in women and their parents.

MEASUREMENTS AND RESULTS

Thirty-three per cent (74/224) had polycystic ovaries on ultrasound. These women had higher birth weights (P = 0.004), higher insulin sensitivity (P = 0.02) and higher leptin levels for body mass index (P = 0.04) than women with normal ovaries. However among women with polycystic ovaries, increasing severity of clinical phenotype (based on number of features of: menstrual irregularity, acne, hirsutism, serum testosterone > 3 mmol/l and LH > 10 IU/l) was associated with decreasing insulin sensitivity (P < 0.0001) and related to paternally transmitted insulin gene VNTR class III alleles (P = 0.03).

CONCLUSION

Women with polycystic ovaries on ultrasound have increased insulin sensitivity and possible leptin resistance, which could predispose to future weight gain. However, in these women the appearance of clinical features of polycystic ovary syndrome is related to insulin resistance and insulin gene VNTR class III alleles.

Research design and statistics in biomechanics and motor control

Biomechanics and motor control researchers measure how the body moves and interacts with its environment. The aim of this review paper is to consider some key issues in research methods in biomechanics and motor control. The review is organized into four sections: proposing, conducting, analysing and reporting research. In the first of these, we emphasize the importance of defining a worthy research question and of planning the study before its implementation to prevent later difficulties in the analysis and interpretation of data. In the second section, we cover selection of trial sizes and suggest that using three trials or more may be beneficial to provide more 'representative' and valid data. The third section on analysis of data concentrates on effect size statistics, qualitative and numerical trend analysis and cross-correlations. As sample sizes are often small, the use of effect size is recommended to support the results of statistical significance testing. In using cross-correlations, we recommend that scatterplots of one variable against the other, with the identified time lag included, be inspected to confirm that the linear relationship assumption underpinning this statistic is met and, if appropriate, that a linearity transformation be applied. Finally, we consider important information related to the issues above that should be included when reporting research. We recommend reporting checks or corrections for violations of underpinning assumptions, and the effect of these checks or corrections, to assist in advancing knowledge in biomechanics and motor control.

Disordered eating attitudes and behaviours in teenaged girls: a school-based study

BACKGROUND

Disordered eating attitudes and behaviours are common in older teens and young women in Western countries. Recent evidence suggests that the prevalence of these disorders is rising and that the age of onset has fallen. In the present study, disturbed eating attitudes and behaviours were evaluated in a large school-based population in Ontario in order to determine their prevalence and demographic distribution.

METHODS

Females, aged 12-18 years, from schools in Toronto, Hamilton and Ottawa were invited to complete questionnaires, including 3 subscales of the Eating Disorder Inventory (Drive for Thinness, Body Dissatisfaction, Bulimia), the Eating Attitudes Test-26 (EAT-26) and the Diagnostic Survey for Eating Disorders (DSED).

RESULTS

Questionnaires were completed by 1739 (70%) of the 2483 adolescent females who were approached. The mean age of subjects in the sample was 14.6 (standard deviation 1.9) years. Thirteen percent of those aged 12-14 years and 16% of those aged 15-18 years had scores above the recommended cut-off (> or = 20) for disordered eating on the EAT-26. Current dieting to lose weight was reported by 23% of participants. Binge eating with associated loss of control was reported by 15% of participants, self-induced vomiting by 8.2% and the use of diet pills by 2.4%. Laxative and diuretic misuse were uncommon. Dieting was associated with an increased risk of binge-eating and purging behaviours. Older age and body mass index in the highest quartile were independently related to symptoms of eating disorders.

INTERPRETATION

Disordered eating attitudes and behaviours were present in over 27% of girls aged 12-18 years and were seen to increase gradually throughout adolescence. Prevention programs to diminish the progression and impact of these disorders should be implemented and assessed.

Traumatic renal artery dissection identified with dynamic helical computed tomography

Intimal tears in the renal arteries typically result from traumatic mechanisms that produce rapid deceleration. These injuries usually progress to secondary thrombosis of the vessel. When the tear leads to dissection with luminal stenosis, early diagnosis and repair will preserve parenchymal function. Computed tomography has replaced intravenous pyelography as the radiographic study of choice for renal trauma. We present two patients with unilateral delay of renal contrast enhancement during dynamic helical computed tomography scan due to arterial stenosis from intimal dissection confirmed with arteriography. Both vessel injuries were successfully managed with endovascular stent placement. No previous description of this diagnostic strategy is reported in the literature.

Expression of multiple forms of clusterin during light-induced retinal degeneration

PURPOSE

Clusterin has been associated with active cell death in several different model systems, including animal models of retinal degeneration. Clusterin is also expressed in normal tissues, a finding that leads to the question of how it could then play a cell death-specific role during tissue regression. To address this paradox, we have examined clusterin expression during light-induced retinal damage in rats.

METHODS

Normal albino rats were reared in darkness and then exposed to intense visible light to induce retinal degeneration. Clusterin expression was then examined at various times after light treatment. Standard molecular techniques including Northern analysis, immunohistochemistry, and Western analysis were employed.

RESULTS

Northern analysis established that the largest increase in clusterin expression occurs after a decrease in interphotoreceptor retinoid binding protein, IRBP, expression (an indication of a photoreceptor cell dysfunction) and after an increase in heme oxygenase 1, HO-1, expression (an oxidative stress inducible gene), suggesting that induction of clusterin expression is an oxidative stress response. Immuno-histochemical analysis with two different clusterin-specific antibodies, anti(SGP-2) and anti(301), localized distinct forms of clusterin to Müller cells and degenerating photo-receptor cells. Western analysis demonstrated degeneration associated isoforms of clusterin in light treated retina that are not present in normal retina.

CONCLUSION

Clusterin over-expression is characteristic of a retinal degeneration phenotype and we propose that clusterin action may be defined by the nature in which it is modified. We hypothesize that alternate processing leads to retinal degeneration-specific forms of the protein (65, 61, and 50 kDa) that are not present in normal retina.

The effects of induced hypogonadism on arterial stiffness, body composition, and metabolic parameters in males with prostate cancer

Sex hormones appear to play a pivotal role in determining cardiovascular risk. Androgen deprivation therapy for males with prostate cancer results in a hypogonadal state that may have important, but as yet undetermined, effects on the vasculature. We studied the effects of androgen deprivation therapy on large artery stiffness in 22 prostate cancer patients (mean age, 67 +/- 8 yr) over a 6-month period. Arterial stiffness was assessed using pulse-wave analysis, a technique that measures peripheral arterial pressure waveforms and generates corresponding central aortic waveforms. This allows determination of the augmentation of central pressure resulting from wave reflection and the augmentation index, a measure of large artery stiffness. Body compositional changes were assessed using bioelectrical impedance analysis. Fasting lipids, glucose, insulin, testosterone, and estradiol were measured. After a 3-month treatment period, the augmentation index increased from 24 +/- 6% (mean +/- SD) at baseline to 29 +/- 9% (P = 0.003) despite no change in peripheral blood pressure. Timing of wave reflection was reduced from 137 +/- 7 to 129 +/- 10 msec (P = 0.003). Fat mass increased from 20.2 +/- 9.4 to 21.9 +/- 9.6 kg (P = 0.008), whereas lean body mass decreased from 63.2 +/- 6.8 to 61.5 +/- 6.0 kg (P = 0.016). There were no changes in lipids or glucose during treatment. Median serum insulin rose from 11.8 (range, 5.6-49.1) to 15.1 (range, 7.3-83.2) mU/liter at 1 month (P = 0.021) and to 19.3 (range, 0-85.0 mU/liter by 3 months (P = 0.020). There was a correlation between the changes in fat mass and insulin concentration over the 3-month period (r = 0.56; P = 0.013). In a subgroup of patients whose treatment was discontinued after 3 months, the augmentation index decreased from 31 +/- 7% at 3 months to 29 +/- 5% by 6 months, in contrast to patients receiving continuing treatment in whom the augmentation index remained elevated at 6 months compared with baseline (P = 0.043). These data indicate that induced hypogonadism in males with prostate cancer results in a rise in the augmentation of central arterial pressure, suggesting large artery stiffening. Adverse body compositional changes associated with rising insulin concentrations suggest reduced insulin sensitivity. These adverse hemodynamic and metabolic effects may increase cardiovascular risk in this patient group.

Treatment practices for chlamydial infection in New Zealand

AIMS

To identify prescribing and treatment practices for chlamydial infection in New Zealand.

METHODS

Postal survey to doctors and nurses at all sexual health, family planning, student and youth health centres, and randomly selected general practitioners.

RESULTS

There was considerable variation in treatment regimes used for chlamydial infection with few respondents treating in accordance with international guidelines regarding dose, frequency, and duration of treatment. Doxycycline (88.4%) was most commonly used to treat uncomplicated chlamydial infection in non-pregnant patients. Most respondents (70.2%) stipulated doxycycline for longer durations than the seven day regimen international guidelines recommend, with doxycycline 100 mg twice a day for ten days most frequently specified. Among the 259 respondents who would treat pregnant women with erythromycin, 51 different treatment regimens were specified, and 51.7% recorded regimens less than that recommended by international guidelines. When treating a patient presumptively, the majority of respondents tested for chlamydial infection. In contrast to other respondents, sexual health clinic staff rarely provide patients with a prescription for a patient's partner without seeing the partner.

CONCLUSIONS

Standardised treatment guidelines are required for patients diagnosed with chlamydial infection. Guidelines should include recommendations for the treatment of partners, and encourage the laboratory confirmation of diagnosis.

Screening and diagnostic practices for chlamydia infections in New Zealand

AIMS

To identify screening and diagnostic practices for chlamydia infection in New Zealand.

METHODS

Postal survey of doctors and nurses at all sexual health, family planning, youth and student clinics, and randomly selected general practitioners (GPs).

RESULTS

Most respondents recognised chlamydia infection as a cause of pelvic inflammatory disease and infertility in females, and epididymitis and non-gonococcal urethritis in males. Ectopic pregnancy and conjunctivitis were less commonly recognised by GPs and student and youth centre doctors. Sterile pyuria and arthritis were well recognised only by sexual health doctors. Female doctors were significantly more likely to recognise signs and symptoms than male doctors. GPs were less likely than other respondents to screen for chlamydia infection. Sexual health doctors and nurses were more likely to remove cervical secretions prior to taking endocervical specimens. Contact tracing was regarded as very important by only a quarter of family planning respondents, compared with over 80% of other respondents.

CONCLUSIONS

While respondents recognised most signs, symptoms, and sequelae of chlamydia infection, some important features were not well recognised. Screening practices varied, and many endocervical specimens were taken incorrectly. Given the long-term health consequences and cost of chlamydia infection sequelae, screening guidelines are urgently required.

Affected sib-pair analysis in endometriosis

This paper (i) reviews the current clinical and molecular genetic data which strongly suggest that endometriosis has a genetic basis; (ii) outlines the general principles of affected-sib pair analysis; and (iii) describes the Oxford Endometriosis Gene (OXEGENE) Study which aims, using a positional cloning approach, to identify susceptibility genes involved in the development of the disease.

Consanguinity and the transmission/disequilibrium test for allelic association

Consanguineous marriages, usually between first cousins or between uncle and niece, are common in certain societies. The transmission/disequilibrium test (TDT) compares the transmission from parents to an affected child of alleles at a marker locus, and differential transmission indicates linkage and allelic association between the marker locus and a disease locus. We investigate the consequences for the TDT, as a test for allelic association, of consanguineous marriages. For each parental marker mating type, we calculate the frequency of each disease mating type, and the associated probability that an offspring is affected. We use Bayes' Theorem to estimate the probability that an affected child inherits the given allele from a heterozygous parent, then combine our results across marker mating types. The effect of consanguineous marriage is usually small. For candidate genes, the effects were greater for uncle-niece marriages, for rare disease alleles, and for high genotype relative risk. For markers, the effects were generally negligible. The Type I error probability of the TDT is essentially unchanged by intermarriage, except for a purely recessive disease allele. The power of the TDT is increased for a recessive allele and decreased for a dominant allele. However, consideration of levels of consanguinity that arise in practice indicates that standard power calculations for the TDT will usually need only minor modification.

Genetic regulation of acquired immune responses to antigens of Mycobacterium tuberculosis: a study of twins in West Africa

The role of genetic factors in clinical tuberculosis is increasingly recognized; how such factors regulate the immune response to Mycobacterium tuberculosis in healthy individuals is unclear. In this study of 255 adult twin pairs residing in The Gambia, West Africa, it is apparent that memory T-cell responses to secreted mycobacterial antigens (85-kDa antigen complex, "short-term culture filtrate," and peptides from the ESAT-6 protein), as well as to the 65-kDa heat shock protein, are subject to effective genetic regulation. The delayed hypersensitivity response to intradermal tuberculin also demonstrates significant genetic variance, while quantitative T-cell and antibody responses to the 38-kDa cell membrane protein appear to be determined largely by environmental factors. Such findings have implications for vaccine development.

Surveillance of sexually transmitted infections in New Zealand, 1998

AIMS

To describe the surveillance and epidemiology of sexually transmitted infections (STIs) in New Zealand.

METHODS

Sexual health clinics submitted STI data to the Institute of Environmental Science and Research (ESR). Infection rates were calculated by dividing the number of diagnoses by the number of total clinic visits. Because the denominator used to calculate infection rates changed in 1998, STI rates in 1998 cannot be directly compared with previous years and case numbers were used to identify recent trends.

RESULTS

In 1998, genital warts was the most commonly diagnosed STI (4.7%), followed by chlamydia (3.0%) and genital herpes (1.0%). Approximately two-thirds of gonorrhoea, chlamydia and genital warts diagnoses were in people aged less than 25 years. Chlamydia rates were 7.3% in Maori, 7.1% in Pacific Island people, and 2.1% in European. Gonorrhoea rates were 1.6% in Maori, 1.9% in Pacific Island people and 0.2% in European. The number of chlamydia and gonorrhoea cases increased between 1995 and 1998.

CONCLUSIONS

The reporting of data by age, sex and ethnicity has allowed a more useful evaluation of the incidence of STIs. The majority of STIs were diagnosed among young New Zealanders, and disproportionately high chlamydia and gonorrhoea infection rates were found among Maori and Pacific Island people.

Maximal expression of membrane-bound nitrate reductase in Paracoccus is induced by nitrate via a third FNR-like regulator named NarR

Respiratory reduction of nitrate to nitrite is the first key step in the denitrification process that leads to nitrate loss from soils. In Paracoccus pantotrophus, the enzyme system that catalyzes this reaction is encoded by the narKGHJI gene cluster. Expression of this cluster is maximal under anaerobic conditions in the presence of nitrate. Upstream from narK is narR, a gene encoding a member of the FNR family of transcriptional activators. narR is transcribed divergently from the other nar genes. Mutational analysis reveals that NarR is required for maximal expression of the membrane-bound nitrate reductase genes and narK but has no other regulatory function related to denitrification. NarR is shown to require nitrate and/or nitrite is order to activate gene expression. The N-terminal region of the protein lacks the cysteine residues that are required for formation of an oxygen-sensitive iron-sulfur cluster in some other members of the FNR family. Also, NarR lacks a crucial residue involved in interactions of this family of regulators with the sigma(70) subunit of RNA polymerase, indicating that a different mechanism is used to promote transcription. narR is also found in Paracoccus denitrificans, indicating that this species contains at least three FNR homologues.

Homeless women and children's access to health care: a paradox

Homeless women and children who reside in shelters experience many health-related problems. The aim of the qualitative study reported here was to (a) explore how shelter staffs manage health problems among their residents and assist them in accessing health services, and (b) identify clinical strategies for community health nurses working with this population. Findings demonstrate a paradox whereby homeless shelter staffs try to gain access to care for their residents through a system that is designed to keep them out. In addition, findings indicate a need for increased community health nursing services in homeless shelters. Strategies for resolving this paradox include providing assessment, policy development, and assurance of health care for homeless women and children.

Grasping a better understanding of the intrinsic dynamics of rhythmical and discrete prehension

In this study, the authors examined the influence of the intrinsic dynamics of discrete and rhythmical prehension. Six adults underwent a scaling procedure in which the movement time was systematically increased so that it corresponded with 6 frequencies: 0.5, 0.75, 1.0, 1.25, 1.5, and 1.75 Hz. In posttests, participants moved at their own preferred pace. No differences were found in the relative time to final hand closure (T[rfc]) between the rhythmical and discrete conditions. The variability of T[rfc] was shown to be less at the preferred step of scaling than during the posttest. With the scaling technique, one can guide participants into more stable movement patterns than they can achieve when the metronome is not present, because, when the metronome is present, their movements become anchored to the external pacing cue. Those findings provide support for the use of a scaling technique to identify the influence of the intrinsic dynamics during rhythmical and discrete movements.

The risk of enteric infections associated with wastewater reuse: the effect of season and degree of storage of wastewater

The effect of season and wastewater storage on the risk of Ascaris lumbricoides infection and diarrhoeal disease associated with wastewater reuse was studied in Mexico in 1991. Data were collected from 10,489 individuals during a dry-season survey. Exposure was to untreated wastewater, or effluent from 1 reservoir (< or = 1 nematode egg/L), or no wastewater irrigation (control group). The results were compared with a previous rainy-season survey which included effluent from 2 reservoirs in series. Direct exposure to untreated wastewater was associated with an excess risk of A. lumbricoides infection in children aged < 5 years (OR = 18.0) and persons aged > 5 years (OR = 13.5) and an increased risk of diarrhoea, particularly to children aged < 5 years (OR = 1.75); effects were stronger in the dry than in the rainy season. There was also an excess risk associated with the 1-reservoir group for A. lumbricoides infection (OR = 21.2 and 9.4) and for diarrhoeal disease (OR = 1.1 and 1.5) but little excess associated with the 2-reservoirs group. Therefore, wastewater retention in 1 reservoir (quality 10(5) faecal coliforms/100 mL, < or = 1 egg/L) does not significantly reduce risks of Ascaris infection and diarrhoeal disease whereas retention in 2 reservoirs in series (quality 10(3) faecal coliforms/100 mL, no detectable eggs/L) does.

Information--movement coupling: implications for the organization of research and practice during acquisition of self-paced extrinsic timing skills

Information--movement coupling is a fundamental concept, integral to theorizing on the coordination of goal-directed activity in ecological psychology. In this paper, we examine the implications of this concept for the design of experimental research and the organization of practice during the acquisition of movement coordination in sport tasks. The task vehicle for our analysis is interceptive actions, in particular self-paced extrinsic timing tasks exemplified by serving in sports such as volleyball. Recent research highlighting the relevance of information--movement coupling for the process of practice in sport is discussed. We conclude that information--movement coupling represents an important principle for the structural organization of research and practice in self-paced extrinsic timing tasks and that further work is required to verify its significance across a range of sport movements.

Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Hemoglobin concentration in children in a malaria holoendemic area is determined by cumulated Plasmodium falciparum parasite densities

In malaria holoendemic areas children are anemic, but the exact influence of falciparum malaria on hemoglobin (Hb) concentration remains largely unsettled. Prospective data were therefore collected in children < 24 months of age during five months in a Tanzanian village. Children with mean asymptomatic parasitemia > or = 400/microl had lower median Hb levels during the study than those with mean density < 400/microl. The difference was 9.7 g/L (95% confidence interval [CI] 2.8-17). In children with one or more clinical malaria episodes, the median Hb was 8.3 g/L (95% CI 0.9-16) lower than those without episode. If early treatment failure was recorded, the immediate effect on Hb was particularly important with a mean drop of 17 g/L. Interestingly, at study-end the Hb concentration represented a function of the area under the parasitemia curve (AUPC) during the previous five months, adjusting for age. In conclusion, stepwise deterioration in median Hb levels was found by asymptomatic parasitemia, clinical malaria episode, and most significantly, treatment failure.

The effects of growth hormone and IGF-1 deficiency on cerebrovascular and brain ageing

Research studies clearly indicate that age-related changes in cellular and tissue function are linked to decreases in the anabolic hormones, growth hormone and insulin-like growth factor (IGF)-1. Although there has been extensive research on the effects of these hormones on bone and muscle mass, their effect on cerebrovascular and brain ageing has received little attention. We have also observed that in response to moderate calorie restriction (a treatment that increases mean and maximal lifespan by 30-40%), age-related decreases in growth hormone secretion are ameliorated (despite a decline in plasma levels of IGF-1) suggesting that some of the effects of calorie restriction are mediated by modifying the regulation of the growth hormone/IGF-1 axis. Recently, we have observed that microvascular density on the surface of the brain decreases with age and that these vascular changes are ameliorated by moderate calorie restriction. Analysis of cerebral blood flow paralleled the changes in vasculature in both groups. Administration of growth hormone for 28 d was also found to increase microvascular density in aged animals and further analysis indicated that the cerebral vasculature is an important paracrine source of IGF-1 for the brain. In subsequent studies, administration of GHRH (to increase endogenous release of growth hormone) or direct administration of IGF-I was shown to reverse the age-related decline in spatial working and reference memory. Similarly, antagonism of IGF-1 action in the brains of young animals impaired both learning and reference memory. Investigation of the mechanisms of action of IGF-1 suggested that this hormone regulates age-related alterations in NMDA receptor subtypes (e.g. NMDAR2A and R2B). The beneficial role of growth hormone and IGF-1 in ameliorating vascular and brain ageing are counterbalanced by their well-recognised roles in age-related pathogenesis. Although research in this area is still evolving, our results suggest that decreases in growth hormone and IGF-1 with age have both beneficial and deleterious effects. Furthermore, part of the actions of moderate calorie restriction on tissue function and lifespan may be mediated through alterations in the growth hormone/IGF-1 axis.

Effects of cricket ball colour and illuminance levels on catching behaviour in professional cricketers

In recent years there have been many alterations to equipment and technology in professional cricket, including the introduction of white balls during day-night matches. In the present study simulated slip-catching performance and movement initiation time were examined in professional cricketers when ball colour and illuminance levels differed. Five male professional cricketers (mean age: 27.3 +/- 1.4 years) volunteered to catch a total of 60 cricket balls, 20 (10 red and 10 white) under each of three illuminance levels (571, 1143 and 1714 lux). Balls were projected from a ball machine at 20 m s(-1) (45 mph) over a distance of 8.4 m, to the subject's dominant side. Catching performance was measured using an established catching scale. Movement initiation times for each hand were also calculated for each trial using a motion-analysis system. Data were submitted to separate two-way (ball colour [2] x illuminance level [3]) repeated measures analysis of variance. No significant effects were obtained for ball colour or illuminance levels for either catching performance or movement initiation time. Neither ball colour nor light level (within the range tested) affected slip-catching performance and movement initiation times in professional cricketers. Therefore it was concluded that the changes made to ball colour and light conditions in professional cricket were not detrimental to catching performance.

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.