Otitis media at 6-monthly assessments of Australian First Nations children between ages 12-36 months: Findings from two randomised controlled trials of combined pneumococcal conjugate vaccines.

OBJECTIVES: In remote communities of northern Australia, First Nations children with hearing loss are disproportionately at risk of poor school readiness and performance compared to their peers with no hearing loss. The aim of this trial is to prevent early childhood persisting otitis media (OM), associated hearing loss and developmental delay. To achieve this, we designed a mixed pneumococcal conjugate vaccine (PCV) schedule that could maximise immunogenicity and thereby prevent bacterial otitis media (OM) and a trajectory of educational and social disadvantage. METHODS: In two sequential parallel, open-label, randomised controlled trials, eligible infants were first allocated 1:1:1 to standard or mixed PCV primary schedules at age 28-38 days, then at age 12 months to a booster dose (1:1) of 13-valent PCV, PCV13 (Prevenar13®, +P), or 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugated vaccine, PHiD-CV10 (Synflorix®, +S). Here we report findings of standardised ear assessments conducted six-monthly from age 12-36 months, by booster dose. RESULTS: From March 2013 to September 2018, 261 children were allocated to booster + P (n = 131) or + S (n = 130). There were no significant differences in prevalence of any OM diagnosis by booster dose or when stratified by primary schedule. We found high, almost identical prevalence of OM in both boost groups at each age (for example 88% of 129 and 91% of 128 children seen, respectively, at primary endpoint age 18 months, difference -3% [95% Confidence Interval -11, 5]). At each age prevalence of bilateral OM was 52%-78%, and tympanic membrane perforation was 10%-18%. CONCLUSION: Despite optimal pneumococcal immunisation, the high prevalence of OM persists throughout early childhood. Novel approaches to OM prevention are needed, along with improved early identification strategies and evaluation of expanded valency PCVs.

Multidrug-resistant tuberculosis in Australia, 1998-2012.

OBJECTIVE: To describe the epidemiology and outcomes of multidrug-resistant tuberculosis (MDR-TB) diagnosed in Australia between 1998 and 2012. DESIGN: A retrospective review was undertaken involving all patients with laboratory-confirmed MDR-TB notified in Australia between 1998 and 2012 inclusive. Demographic, clinical and laboratory features are described. Clinical outcomes were defined according to World Health Organization definitions of treatment success (cure and treatment completion), treatment failure, death, loss to follow-up (including transfer out), or not evaluated at treatment completion. RESULTS: A total of 244 cases of MDR-TB were diagnosed in Australia during the study period, representing 1.4% of all TB cases notified. The majority were born outside Australia, including one third in Papua New Guinea. Of those with treatment outcome data available, treatment success was demonstrated in 81%. Treatment success was positively associated with use of a second-line injectable agent. Those born in Papua New Guinea were less likely to achieve treatment success. CONCLUSION: MDR-TB is uncommon in Australia. The large number of cases born in Papua New Guinea, and the poorer outcomes in this cohort, represent challenges with cross-border management of MDR-TB in the Torres Strait. Australia has an ongoing role in the prevention and management of MDR-TB locally and in the region.

Transcranial direct current stimulation (tDCS) applied to the left dorsolateral premotor cortex (dPMC) interferes with rhythm reproduction.

Movement timing in the sub-second range engages a brain network comprising cortical and sub-cortical areas. The present study aims at investigating the functional significance of the left dorsolateral premotor cortex (dPMC) for precise movement timing as determined by sensorimotor synchronization and rhythm reproduction. To this end, 18 healthy volunteers performed an auditorily paced synchronization-continuation task with the right hand. A simple reaction time task served as control condition. Transcranial direct current stimulation (tDCS) was applied over the left dPMC in order to modulate cortical excitability either with anodal or cathodal polarity or as sham stimulation. TDCS was applied for 10 minutes, respectively on separate days. For the continuation task the analysis revealed significantly smaller inter-tap intervals (ITIs) following cathodal tDCS suggesting movement hastening as well as a trend towards larger ITIs following anodal stimulation suggesting movement slowing. No significant effect was found following sham stimulation. Neither for synchronization nor for reaction time tasks significant polarity-specific effects emerged. The data suggest the causal involvement of the dPMC in temporally precisereproduction of isochronous rhythms rather than sensorimotor synchronization. The present findings support the hypothesis that different cortical brain areas within the motor-control-network distinctively contribute to movement timing in the sub-second range.

High burden of invasive group A streptococcal disease in the Northern Territory of Australia.

Although the incidence of invasive group A streptococcal disease in northern Australia is very high, little is known of the regional epidemiology and molecular characteristics. We conducted a case series of Northern Territory residents reported between 2011 and 2013 with Streptococcus pyogenes isolates from a normally sterile site. Of the 128 reported episodes, the incidence was disproportionately high in the Indigenous population at 69·7/100 000 compared to 8·8/100 000 in the non-Indigenous population. Novel to the Northern Territory is the extremely high incidence in haemodialysis patients of 2205·9/100 000 population; and for whom targeted infection control measures could prevent transmission. The incidences in the tropical north and semi-arid Central Australian regions were similar. Case fatality was 8% (10/128) and streptococcal toxic shock syndrome occurred in 14 (11%) episodes. Molecular typing of 82 isolates identified 28 emm types, of which 63 (77%) were represented by four emm clusters. Typing confirmed transmission between infant twins. While the diverse range of emm types presents a challenge for effective coverage by vaccine formulations, the limited number of emm clusters raises optimism should cluster-specific cross-protection prove efficacious. Further studies are required to determine effectiveness of chemoprophylaxis for contacts and to inform public health response.

Pitch Memory in Nonmusicians and Musicians: Revealing Functional Differences Using Transcranial Direct Current Stimulation.

For music and language processing, memory for relative pitches is highly important. Functional imaging studies have shown activation of a complex neural system for pitch memory. One region that has been shown to be causally involved in the process for nonmusicians is the supramarginal gyrus (SMG). The present study aims at replicating this finding and at further examining the role of the SMG for pitch memory in musicians. Nonmusicians and musicians received cathodal transcranial direct current stimulation (tDCS) over the left SMG, right SMG, or sham stimulation, while completing a pitch recognition, pitch recall, and visual memory task. Cathodal tDCS over the left SMG led to a significant decrease in performance on both pitch memory tasks in nonmusicians. In musicians, cathodal stimulation over the left SMG had no effect, but stimulation over the right SMG impaired performance on the recognition task only. Furthermore, the results show a more pronounced deterioration effect for longer pitch sequences indicating that the SMG is involved in maintaining higher memory load. No stimulation effect was found in both groups on the visual control task. These findings provide evidence for a causal distinction of the left and right SMG function in musicians and nonmusicians.

Molecular characterization of an Australian serotype 1 Streptococcus pneumoniae outbreak.

Serotype 1 Streptococcus pneumoniae is a cause of invasive pneumococcal disease (IPD) worldwide and has been associated with IPD outbreaks, while carriage is rarely detected in healthy adults or children. This study details an Australian multi-state and territory outbreak of serotype 1 S. pneumoniae IPD between 2010 and 2012. Molecular characterization demonstrated the outbreak was largely due to the clonal expansion of sequence type 306, MLVA type 261 S. pneumoniae serotype 1.

Changes of motor-cortical oscillations associated with motor learning.

Motor learning results from practice but also between practice sessions. After skill acquisition early consolidation results in less interference with other motor tasks and even improved performance of the newly learned skill. A specific significance of the primary motor cortex (M1) for early consolidation has been suggested. Since synchronized oscillatory activity is assumed to facilitate neuronal plasticity, we here investigate alterations of motor-cortical oscillations by means of event-related desynchronization (ERD) at alpha (8-12 Hz) and beta (13-30 Hz) frequencies in healthy humans. Neuromagnetic activity was recorded using a 306-channel whole-head magnetoencephalography (MEG) system. ERD was investigated in 15 subjects during training on a serial reaction time task and 10 min after initial training. The data were compared with performance during a randomly varying sequence serving as control condition. The data reveal a stepwise decline of alpha-band ERD associated with faster reaction times replicating previous findings. The amount of beta-band suppression was significantly correlated with reduction of reaction times. While changes of alpha power have been related to lower cognitive control after initial skill acquisition, the present data suggest that the amount of beta suppression represents a neurophysiological marker of early cortical reorganization associated with motor learning.

Effects of 10 Hz and 20 Hz transcranial alternating current stimulation (tACS) on motor functions and motor cortical excitability.

Synchronized oscillatory activity at alpha (8-12 Hz) and beta (13-30 Hz) frequencies plays a key role in motor control. Nevertheless, its exact functional significance has yet to be solved. Transcranial alternating current stimulation (tACS) allows the frequency-specific modulation of ongoing oscillatory activity. The goal of the present study was to investigate the effect of 10 and 20 Hz tACS over left primary motor cortex (M1) on motor functions and cortical excitability in healthy subjects. To this end, tACS was applied for 10 min. Sham stimulation served as control condition. Movement speed and accuracy of the right hand were assessed in 15 right-handed subjects before and after (0, 30 and 60 min) tACS of M1. Cortical silent period (CSP) and motor evoked potentials (MEPs) were determined as measures of M1 excitability. While 10 Hz tACS particularly increased movement variability, especially in tasks requiring internal pacing, 20 Hz tACS resulted in movement slowing. Behavioural effects occurred in distinct time windows. While 10 Hz effects developed over 30 min after stimulation, 20 Hz tACS effects were found immediately after stimulation. Following 10 Hz tACS these effects were significantly correlated with CSP duration, indicating interference with inhibitory pathways. The present findings suggest differential effects of stimulation frequency on motor behaviour and M1 excitability.

HIV testing rate in the top end of the Northern Territory of Australia: room for improvement.

The Northern Territory of Australia has an exceptionally high prevalence of sexually transmitted infections (STIs), particularly in remote areas. In contrast there are few notified cases of HIV at present. This study describes HIV testing rates in both primary care and sexual health clinics in the Top End region. In 2010, medical records were reviewed for a random sample of patients from a sexual health clinic and three remote primary care clinics. Among sexual health clinic patients 51.4% overall, and 59.7% of those with an STI, were tested for HIV. In people diagnosed with an STI in remote primary care clinics 19.1% were tested for HIV. HIV testing rates in the Top End of the Northern Territory do not meet the standard of national and international guidelines, with implications both for the early initiation of therapy and the accuracy of surveillance in a region with very high rates of STIs.

Motor-cortical oscillations in early stages of Parkinson's disease.

Pathophysiological changes in basal ganglia-thalamo-cortical circuits are well established in idiopathic Parkinson's disease (PD). However, it remains open whether such alterations already occur at early stages representing a characteristic neurophysiological marker of PD. Therefore, the present study aims at elucidating changes of synchronised oscillatory activity in early PD patients. In this study, we performed whole-head magnetoencephalography (MEG) in a resting condition and during steady state contraction of the more severely affected forearm in 10 drug­naive, de novo patients, in 10 early-stage patients with chronic medication and in 10 age-matched control subjects. While cortico-muscular coherence (CMC) did not differ between groups, patients showed increased sensori-motor cortical power at beta frequency (13­30 Hz) during rest as well as during isometric contraction compared to controls. In healthy control subjects the power of the contralateral hemisphere was significantly suppressed during isometric contraction. By contrast, both hemispheres were activated equally strongly in de novo patients. In medicated patients, the pattern was found to be reversed. Contralateral beta power was significantly correlated with motor impairment during isometric contraction but not during rest. The present results suggest that the reduced ability of the primary motor cortex to disengage from increased beta band oscillations during the execution of movements is an early marker of PD.

Failure to vaccinate or failure of vaccine? Effectiveness of the 23-valent pneumococcal polysaccharide vaccine program in Indigenous adults in the Northern Territory of Australia.

Over the last decade, there has been no discernible reduction in Invasive Pneumococcal Disease (IPD) amongst Indigenous adults in the Northern Territory (NT) of Australia, despite increasing vaccination coverage. We examined the utility of two common methods, the screening method and the indirect method, to determine the 23-valent pneumococcal polysaccharide vaccine effectiveness (VE) in prevention of IPD amongst Indigenous adults in this setting. VE was calculated for the period 2001-2005 across two distinct geographical areas where the disease burden was known to differ. VE against vaccine-type IPD was 3.4% (95% CI -43, 35) for the NT. However, population vaccination coverage varied widely according to geographical region and where this was within the range appropriate for the use of the screening method, VE was within the expected range (67.2%, 95% CI 47, 80). VE according to the indirect cohort appeared unreliable in this setting due to the analysis being based on a very limited number of non-vaccine-type IPD cases. Surveillance based estimates of VE such as these need to be considered with caution, but the results suggest failure to vaccinate is the most likely reason vaccine-type IPD has not reduced in this setting.

Cell-mediated immune response to Leishmania chagasi experimental infection of BALB/c immunosuppressed mice

Leishmaniasis, a zoonosis of worldwide distribution, presents a significant impact on immunosupressed patients. This study aimed to evaluate Leishmania chagasi infection in BALB/c mice immunosuppressed with dexamethasone. Spleen cells stimulated or not with L. chagasi were cultured for cytokine quantification (IFN-gama, IL-2, IL-4 and IL-10) by sandwich ELISA. Parasite loads in the spleen and liver were determined by means of culture microtitration. Immunosuppressed groups showed statistically lower spleen weight and CD4-cell percentage in blood on the day of infection and produced Th1 and Th2 cytokines on other days of the study. The other infected groups, weather immunosupressed or not, also produced Th1 and Th2 cytokines. Parasite loads in the spleen and liver were not statistically different among the groups. It was concluded that L. chagasi infection was not affected by dexamethasone-induced immunosuppression, probably due the reversible effect of the treatment.

Age-specific cluster of cases of serotype 1 Streptococcus pneumoniae carriage in remote indigenous communities in Australia.

Seven-valent pneumococcal conjugate vaccination commenced in 2001 for Australian indigenous infants. Pneumococcal carriage surveillance detected substantial replacement with nonvaccine serotypes and a cluster of serotype 1 carriage. Our aim was to review Streptococcus pneumoniae serotype 1 carriage and invasive pneumococcal disease (IPD) data for this population and to analyze serotype 1 isolates. Carriage data were collected between 1992 and 2004 in the Darwin region, one of the five regions in the Northern Territory. Carriage data were also collected in 2003 and 2005 from four regions in the Northern Territory. Twenty-six cases of serotype 1 IPD were reported from 1994 to 2007 in the Northern Territory. Forty-four isolates were analyzed by BOX typing and 11 by multilocus sequence typing. In the Darwin region, 26 children were reported carrying serotype 1 (ST227) in 2002 but not during later surveillance. Scattered cases of serotype 1 carriage were noted in two other regions. Cocolonization of serotype 1 with other pneumococcal serotypes was common (34% serotype 1-positive swabs). In conclusion, pneumococcal carriage studies detected intermittent serotype 1 carriage and an ST227 cluster in children in indigenous communities in the Northern Territory of Australia. There was no apparent increase in serotype 1 IPD during this time. The rate of serotype 1 cocolonization with other pneumococcal serotypes suggests that carriage of this serotype may be underestimated.

Seroprevalence of Burkholderia pseudomallei in East Timorese refugees: implications for healthcare in East Timor.

Melioidosis is a disease with protean clinical manifestations caused by the bacterium Burkholderia pseudomallei. It is endemic in countries surrounding the newly independent East Timor, but has yet to be isolated or demonstrated serologically in that country. One illness that can be clinically indistinguishable from melioidosis is pulmonary tuberculosis, a condition with a very high prevalence in East Timor. We used an indirect hemagglutination test (IHA) to measure antibodies to B. pseudomallei in 407 East Timorese evacuated to Darwin, Australia, in September 1999. Assuming a positive IHA titer as > or = 1:40, the overall seroprevalence rate was 17.0%, in keeping with other seroprevalence studies from the region. The IHA titres ranged up to 1:320. After adjusting for age, females were 2.5 times more likely to be seropositive than males (p = 0.0001). There was an inverse relationship between seropositivity and age. This study shows that exposure to B. pseudomallei occurs in East Timor melioidosis is also likely to occur. Due to the lack of laboratory facilities at present, it may be some time before a laboratory-confirmed case proves that melioidosis occurs. In the meantime, clinicians in East Timor should include melioidosis in the differential diagnosis of the many conditions that it may mimic.

Pilot study of dermal and subcutaneous fat structures by MRI in individuals who differ in gender, BMI, and cellulite grading.

BACKGROUND/AIMS: Puckered, dimply skin on the thighs, hips, and buttocks is known as cellulite. The cause of cellulite is not known, although there are a number of different hypotheses. In this study, we use magnetic resonance (MR) micro-imaging to study cellulite skin. To the best of our knowledge, this is the first reported MR study of cellulite. METHODS: High-resolution in vivo MR images of the postlateral thigh skin of two male groups and four female groups were obtained. Subjects were grouped according to their body mass index (BMI) and cellulite grade. A qualitative assessment of how MRI can be used to differentiate skin tissue at different levels of cellulite grading was performed. RESULTS: We found that changes in skin architecture with cellulite can be visualized by in vivo MR micro-imaging. The skin fat layers beneath the dermis and down to the level of muscles are well visualized in the images. Also, the diffuse pattern of extrusion of underlying adipose tissue into dermis is clearly imaged, and was found to correlate with cellulite grading. We also show that other skin tissue parameters such as (a) the percentile of adipose vs. connective tissue in a given volume of hypodermis and (b) the percentile of hypodermic invaginations inside the dermis are correlated with cellulite grade. CONCLUSION: MR images can be interpreted to measure tissue parameters correlated with cellulite. Considering that we had only three subjects in each group, the achievements of this pilot study were highly satisfactory. We have shown that the in vivo micro-MR is a technique able to detect the effects of cellulite and gender. This study can be extended for further investigations of drugs and/or medical devices for cellulite treatment.

Noninvasive assessment of the injured human spinal cord by means of functional magnetic resonance imaging.

STUDY DESIGN: A magnetic resonance imaging technique that enables indirect detection of neuronal activity has been developed for the spinal cord. In the present study, this method, spinal functional magnetic resonance imaging (fMRI), is applied to the first study of the injured spinal cord, with the goal of better clinical assessment of the entire cord. OBJECTIVES: The objectives of this project are: (1) to investigate the neuronal activity that can be detected in the spinal cord caudal to a chronic injury by means of spinal fMRI, and (2) to develop spinal fMRI as a clinical diagnostic tool. SETTING: Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada. METHODS: fMRI of the spinal cord was carried out in 27 volunteers with cervical or thoracic spinal cord injuries (SCIs). Of these volunteers, 18 had complete injuries, and nine had incomplete injuries. Spinal fMRI was carried out in a 1.5 T clinical MR system, using established methods. Thermal stimulation at 10 degrees C was applied to the fourth lumbar dermatome on each leg, and images were obtained of the entire lumbar spinal cord. RESULTS: Areas of neuronal activity were consistently observed in the lumbar spinal cord in response to the thermal stimulation, even when the subjects had no awareness of the sensation. The pattern of activity was notably different compared with noninjured subjects. In general, subjects with complete SCI showed absent or diminished dorsal gray matter activity, but had enhanced ventral activity, particularly contralateral to the stimulation. CONCLUSIONS: Spinal fMRI is able to provide a noninvasive assessment of the injured spinal cord that does not depend on the patient's perception of the stimulus being applied. This work was carried out on a standard clinical MRI system without modification, and so is readily applicable in most MR units. SPONSORSHIP: This work was funded by a grant from the Canadian Institutes of Health Research (CIHR).

Functional magnetic resonance imaging of the human brain based on signal enhancement by extravascular protons (SEEP fMRI).

Functional magnetic resonance imaging (fMRI) studies of the human brain were carried out at 3 Tesla to investigate an fMRI contrast mechanism that does not arise from the blood oxygen-level dependent (BOLD) effect. This contrast mechanism, signal enhancement by extravascular protons (SEEP), involves only proton-density changes and was recently demonstrated to contribute to fMRI signal changes in the spinal cord. In the present study it is hypothesized that SEEP fMRI can be used to identify areas of neuronal activity in the brain with as much sensitivity and precision as can be achieved with BOLD fMRI. A detailed analysis of the areas of activity, signal intensity time courses, and the contrast-to-noise ratio (CNR), is also presented and compared with the BOLD fMRI results. Experiments were carried out with subjects performing a simple finger-touching task, or observing an alternating checkerboard pattern. Data were acquired using a conventional BOLD fMRI method (gradient-echo (GE) EPI, TE = 30 ms), a conventional method with reduced BOLD sensitivity (GE-EPI, TE = 12 ms), and SEEP fMRI (spin-echo (SE) EPI, TE = 22 ms). The results of this study demonstrate that SEEP fMRI may provide better spatial localization of areas of neuronal activity, and a higher CNR than conventional BOLD fMRI, and has the added benefit of lower sensitivity to field inhomogeneities.

Mapping of neuronal function in the healthy and injured human spinal cord with spinal fMRI.

Functional magnetic resonance imaging of the human spinal cord is carried out with a graded thermal stimulus in order to establish the relationship between signal changes and neural activity. Studies of the lumbar spinal cord in 15 healthy subjects with 10 degrees C stimulation of the skin overlying the calf demonstrate a pattern of activity that matches the neuronal anatomy of the spinal cord. This pattern shows primarily dorsal horn activity, with expected components of motor reflex activity as well. Moreover, a later response shifting to noxious cold over time is also demonstrated with a shift to more dorsal horn activity. Signal intensity changes detected at different degrees of thermal stimulation have a biphasic nature, with much larger signal changes below 15 degrees C as the stimulus becomes noxious, and agree well with electrophysiological results reported in the literature. These findings demonstrate a strong correspondence between Spinal fMRI results and neural activity in the human spinal cord. Spinal fMRI is also applied to studies of the injured spinal cord, below the site of injury. Results consistently demonstrate activity in the spinal cord even when the subjects cannot feel the stimulus being applied. Signal intensity changes demonstrate the same stimulus-response pattern as that in noninjured subjects, but the areas of activity in the spinal gray matter are notably altered. In subjects with complete injuries, activity is absent ipsilateral to the thermal stimulation, but appears to be enhanced on the contralateral side. These findings demonstrate the reliability of Spinal fMRI and its clinical potential.

Tuberculosis in east timorese refugees: implications for health care needs in East Timor.

SETTING: East Timorese refugees evacuated to Darwin, Australia, September 1999. OBJECTIVE: Presentation of the process and results of tuberculosis (TB) screening in a previously unscreened refugee population. DESIGN: Screening for TB by clinical examination (all persons) and chest X-ray (CXR) (persons over 12 years of age and those of any age with respiratory symptoms) and sputum microscopy and mycobacterial culture (abnormal CXR). RESULTS: Seventy-six patients were diagnosed with TB (38 culture-positive for Mycobacterium tuberculosis, including 11 sputum smear-positive). Of 89 positive mycobacterial cultures, 51 were non-tuberculous mycobacteria (NTM). Of the M. tuberculosis isolates, 82.2% were fully sensitive, 17.2% were resistant to isoniazid and 8.6% were resistant to isoniazid and streptomycin. Fifty-three consecutively diagnosed patients with TB were HIV-negative. The TB burden in this population was very high (point prevalence of 542/100,000 for smear-positive and 2,060/100,000 for culture-positive cases). Rates of culture for NTM were also high. Information from this study assisted the implementation of a National TB Control Programme for East Timor in February 2000. CONCLUSION: The challenges for public health authorities in East Timor to provide a successful TB control programme are enormous. The apparently low prevalence of drug resistance and HIV co-infection in the population is encouraging.