Health issues of refugees attending an infectious disease refugee health clinic in a regional Australian hospital

BACKGROUND AND OBJECTIVES

Refugees in Australia present with conditions different to those of the general population. The aim of this study was to review the reasons for referral, prevalence of conditions and treatment outcomes for refugee patients attending a specialist referral clinic in regional Victoria.

METHOD

A retrospective review was undertaken of patients attending the refugee health clinic at University Hospital Geelong from January 2007 to December 2012.

RESULTS

Two hundred and ninety-one refugee patients attended the clinic over the six-year period. Latent tuberculosis infection (LTBI) (54.6%), vitamin deficiencies (15.8%), hepatitis B (11%) and schistosomiasis (11%) were the most common diagnoses. Less than two-thirds of the patients completed LTBI treatment; 35.4% of patients attended all scheduled clinic appointments.

DISCUSSION

LTBI, vitamin deficiencies, parasitic infections and hepatitis B were the most common diagnoses among refugees referred to the University Hospital Geelong (UHG) Refugee Health Clinic from January 2007 to December 2012. General practitioners play an important role in the care of refugees, guiding referral to specialist services when necessary and recognising the potential implications of suboptimal clinic attendance and treatment completion.

Perinatal microbial exposure may influence aortic intima-media thickness in early infancy

Background

The maternal and infant microbiome may influence infant cardiovascular risk through immune programming. The maternal vagino-enteric microbiome is often sampled for group B streptococcus (GBS) colonization during pregnancy. Our aim was to investigate the association between maternal GBS colonization, intrapartum antibiotics, antenatal pet exposure and infant aortic intima-media thickness (aIMT), an intermediate vascular phenotype, and whether this association varied by mode of delivery.

Methods

The Barwon Infant Study is a population-derived pre-birth cohort. Perinatal data were collected on participants. Women were tested for vagino-enteric group B streptococcus (GBS) colonization during third trimester. Six-week infant aIMT was measured by trans-abdominal ultrasound. Adjustment for confounders included maternal age, pre-pregnancy body mass index (BMI), smoking, socioeconomic status, gestational diabetes, length of gestation, infant sex, birthweight and aortic internal diameter.

Results

Data were available on 835 mother-infant pairs. Of these, 574 (69%) women delivered vaginally; of those, 129 (22%) were GBS-colonized; and of these women, 111 (86%) received prophylactic intrapartum antibiotics. An association between maternal GBS colonization and infant aIMT was observed among those delivered vaginally (β = 19.5 µm, 95% CI 9.5, 29.4; P  < 0.0001) but not by Caesarean section ( P for interaction = 0.02). A similar pattern was seen for intrapartum antibiotics. There was a negative association between antenatal pet exposure and aIMT observed in those delivered vaginally.

Conclusion

Maternal GBS colonization and intrapartum antibiotics were associated with increased infant aIMT in those delivered vaginally, whereas antenatal pet exposure was associated with decreased aIMT. These data suggest that differences in early life microbial experience may contribute to an increased cardiovascular risk.

Early-Life Markers of Atherosclerosis Using Aortic and Carotid Intima-Media Thickness: An Assessment of Methods to Account for Child Size

Background

Distinguishing pathological from physiological relationships between vessel size and aortic intima-media thickness (aIMT) is an important challenge, especially in growing children. We examined the relationship between childhood vessel diameter and aIMT and assessed common analytic approaches used to address this relationship.

Methods

We analyzed aIMT in two population-derived cohorts; 6-week-old infants and 19-year-olds. We simulated datasets in which we assumed a simple physiological relationship between vessel diameter and aIMT, and then superimposed possible pathological effects on aIMT; (a) intrauterine growth retardation, (b) macrosomia and (c) both intrauterine growth retardation and macrosomia. Using simulated datasets and cohorts, we evaluated analytic strategies including those in which the relationship between vessel diameter and aIMT was (a) ignored, (b) adjusted for by dividing aIMT by weight, or (c) adjusted for using varying regression techniques.

Results

aIMT was found to increase in proportion to vessel diameter in both cohorts (138 μm/mm at 6 weeks and 52 μm/mm at 19 years of age). Simply dividing aIMT by weight produced negative associations with weight across all datasets. By contrast, adjusting for vessel diameter as a covariate enabled accurate distinction of the direction of the association between aIMT and weight in all simulated datasets. These results were replicated in the cohort studies for both aIMT and carotid intima-media thickness.

Conclusion

There is a physiological relationship between vessel diameter and aIMT. Simply dividing aIMT by weight may lead to incorrect assumptions regarding the relationship between weight and aIMT. However, the physiological relationship is appropriately estimated by including vessel diameter as a covariate in regression.

Gestational Age and the Cord Blood Lipidomic Profile in Late Preterm and Term Infants

BACKGROUND

Lipid metabolism is vital to fetal development and cardiometabolic health and the final weeks of gestation are known to be a time of intense metabolic activity. New techniques such as lipidomics allow investigation of a complex lipidomic profile in infants.

OBJECTIVES

This research aimed to (1) describe variations in lipidomic profile in late preterm and term infants and (2) compare variations to an adult lipidomic profile with known clinical implications.

METHODS

The Barwon Infant Study (n = 1,074) is a population-derived pre-birth cohort study. The lipidomic profile of cord blood was measured by liquid chromatography-mass spectrometry in 225 participants and the association between gestational age and lipidomic profile was investigated using multiple linear regression adjusting for birth weight, exposure to labour, and infant sex. Patterns of association with gestational age across the lipidomic profile were compared with associations between body mass index (BMI) and lipidomic profile observed among adults in the San Antonia Family Heart Study (n = 994).

RESULTS

Gestational age was independently associated with the abundances of 39% of lipid species. Variations in the lipidomic profile with increasing gestational age were comparable to some variations observed in association with increasing BMI among adults.

CONCLUSION

There is a strong relationship between gestational age and the cord blood lipid profile at birth, providing further evidence for the importance of metabolic changes of late gestation. A number of the variations in the lipid profile with increasing gestational age are analogous to differences observed in the adult lipid profile with an increasing BMI.

The association between higher maternal pre-pregnancy body mass index and increased birth weight, adiposity and inflammation in the newborn

BACKGROUND

Excess adiposity and adiposity-related inflammation are known risk factors for cardiovascular disease in adults; however, little is known regarding the determinants of adiposity-related inflammation at birth.

OBJECTIVES

The aim of this study was to investigate the association between maternal pre-pregnancy BMI and newborn adiposity and inflammation.

METHODS

Paired maternal (28-week gestation) and infant (umbilical cord) blood samples were collected from a population-derived birth cohort (Barwon Infant Study, n = 1074). Data on maternal comorbidities and infant birth anthropomorphic measures were compiled, and infant aortic intima-media thickness was measured by trans-abdominal ultrasound. In a selected subgroup of term infants (n = 161), matched maternal and cord lipids, high-sensitivity C-reactive protein (hsCRP) and maternal soluble CD14 were measured. Analysis was completed by using pairwise correlation and linear regression. Because of their non-normal distribution, pathology blood measures were log transformed prior to analysis.

RESULTS

Maternal pre-pregnancy BMI was positively associated with increased birth weight (mean difference 17.8 g per kg m^-2 , 95% CI 6.6 to 28.9; p = 0.002), newborn mean skin-fold thickness (mean difference 0.1 mm per kg m^-2 , 95% CI 0.0 to 0.1; p < 0.001) and cord blood hsCRP (mean difference of 4.2% increase in hsCRP per kg m^-2 increase in pre-pregnancy BMI, 95% CI 0.6 to 7.7%, p = 0.02), but not cord blood soluble CD14. Inclusion of maternal hsCRP as a covariate attenuated the associations between pre-pregnancy BMI and both newborn skin-fold thickness and cord blood hsCRP.

CONCLUSION

Higher maternal pre-pregnancy BMI is associated with increased newborn adiposity and inflammation. These associations may be partially mediated by maternal inflammation during pregnancy.

Reproducibility of aortic intima-media thickness in infants using edge-detection software and manual caliper measurements

Background

Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality.

Methods

Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability.

Results

Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA −39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA −45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA −51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p < 0.001, mean difference 44 μm, 95% LOA −54, 142). With the exception of infant crying (p = 0.001), no associations were observed between individual and environmental variables and image quality.

Conclusion

In a population-derived cohort of term infants, aIMT measurement has a high level of intra and inter-reader reproducibility. Measurement of aIMT using edge-detection software gives higher inter-reader ICC than manual sonographic calipers. Image quality is not substantially affected by individual and environmental factors.

Aortic intima-media thickness measured by trans-abdominal ultrasound as an early life marker of subclinical atherosclerosis

Atherosclerosis is a chronic inflammatory process that begins in early life. Improved identification of markers of early atherosclerosis via neonatal aortic intima-media thickness (aIMT) measurement may allow the development of interventions to prevent or reduce later cardiovascular disease.

CONCLUSION

Using aIMT, studies have shown that antenatal factors such as intra-uterine growth retardation, prematurity, maternal factors and inflammation are associated with early cardiovascular changes.

The use of magnetite-doped polymeric microspheres in calibrating cell tracking velocimetry

Continuous magnetic separation, in which there is no accumulation of mass in the system, is an inherently dynamic process, requiring advanced knowledge of the separable species for optimal instrument operation. By determining cell magnetization in a well-defined field, we may predict the cell trajectory behavior in the well-characterized field environments of our continuous separators. Magnetization is determined by tracking the migration of particles with a technique known as cell tracking velocimetry (CTV). The validation of CTV requires calibration against an external standard. Furthermore, such a standard, devoid of the variations and instabilities of biological systems, is needed to reference the method against day-to-day shifts or trends. To this end, a method of synthesizing monodisperse, magnetite-doped polymeric microspheres has been developed. Five sets of microspheres differing in their content of magnetite, and each of approximately 2.7 microm diameter, are investigated. An average gradient of 0.18 T/mm induces magnetic microsphere velocities ranging from 0.45 to 420 microns/s in the CTV device. The velocities enable calculation of the microsphere magnetization. Magnetometer measurements permit the determination of magnetization at a flux density comparable to that of the CTV magnet's analysis region, 1.57 T. A comparison of the results of the CTV and magnetometer measurements shows good agreement.

Quantification of cellular properties from external fields and resulting induced velocity: cellular hydrodynamic diameter

An experimental technique is discussed in which the size distribution of a population of cells is determined by calculating each cell's settling velocity. The settling velocity is determined from microscopically obtained images which were recorded on SVHS tape. These images are then computer imaged and processed, and the cell's location and velocity are determined using a computer algorithm referred to as cell tracking velocimetry (CTV). Experimental data is presented comparing the distribution of human lymphocytes and a human breast cancer cell line, MCF-7, determined using a Coulter counter and the CTV approach.

Quantification of cellular properties from external fields and resulting induced velocity: magnetic susceptibility

An experimental technique is discussed in which the magnetic susceptibility of immunomagnetically labeled cells can be determined on a cell-by-cell basis. This technique is based on determining the magnetically induced velocity that an immunomagnetically labeled cell has in a well-defined magnetic energy gradient. This velocity is determined through the use of video recordings of microscopic images of cells moving in the magnetic energy gradient. These video images are then computer digitized and processed using a computer algorithm, cell tracking velocimetry, which allows larger numbers (>10(3)) of cells to be analyzed.

Evaluation of integrated night vision goggle (NVG) helmets under sustained +Gz

Three integrated night vision goggle (NVG) helmets from different manufacturers were evaluated under high-G conditions. Structural and operational integrity, as well as neck forces in pounds, were determined via instrumented manikin testing before human exposure with the helmets during sustained +Gz. Results of the manikin testing showed that the helmets could withstand the rigors of high-G, and that predicted forces (using helmet weights and centers-of-gravity) matched those obtained experimentally from load cells in the x-axis of the manikin's neck. After manikin testing, 10 subjects were randomly exposed to four different high-G profiles on the Dynamic Environmental Simulator (DES) man-rated centrifuge located at Wright-Patterson AFB, OH: gradual onset to +8 Gz, a simulated aerial combat maneuver (SACM) profile, and two +4 Gz profiles, one with the mask dangling from the helmet and the other with the mask removed. Fit assessments were conducted before high-G exposure, and one helmet was affected significantly by failure of fit. The degree of migration of the NVG intensified image away from the eyes was affected most by the following helmet characteristics: design of the nape strap, size of the NVG image provided by each helmet system, goodness of helmet fit, and the use of the mask as a stabilizer. Although neck strength of each subject was measured and compared to the degree of head stability while wearing each helmet, no effects were found. However, subjects were not allowed to perform fast, high-amplitude head movements in the centrifuge for safety reasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethics in human experimentation: examples in aeromedical research

The existence of ethical standards directing how humans are utilized in clinical and human-use research have a significant impact on the conduct and outcome of aeromedical research. The validity of the data generated by human research is a direct result of the application of these ethical guidelines. The risk/benefit ratio evaluation can terminate a project even before its initiation. New technology, individual beliefs, and a changing society will continue to guarantee controversy over how human subjects should be screened and evaluated as well as how research should utilize them. Ethical guidelines are not cast in stone. Their interpretation is influenced by new experimental results, the individual researcher, the intended subject, the composition of human use committees, and the social environment. How we address new and old concerns alike will dictate the research environment of the future.

Ethics in human experimentation: historical perspectives

Ethics has received renewed attention recently as evidenced by recent revelations of experimentation on Eskimos during the 1950s and a new President vowing to raise ethical standards of conduct within government. There is also an ongoing, intense scrutiny of past radiation-exposure experiments with all of its possible ethical violations. This paper is a modest attempt to familiarize the reader with some of the historical development of ethics in human-use research. Debate concerning the use of humans as subjects of medical and behavioral experimentation has a long and distinguished history going back at least 2,000 years. A short historical review reveals that ethical behavior exhibits a pendulum action between the extremes of protection of humans at all costs and the attainment of scientific knowledge at all costs. Only by knowing the historical foundation of ethics can one understand the current issues surrounding human experimentation.

Individual differences and subgroups within populations: the shopping bag approach

The aerospace medical research community needs to consider the individual as something other than a statistical entity. The cumulative effects of performance enhancers that are collectively ignored, secondary to statistical analysis of populations, can be significant for individuals. By considering the individual, all aspects of whatever makes humans unique need to be integrated into research. One suggested remedy to the problem of subordination of the individual to the population mean/standard deviation is the use of a "shopping bag" approach. In this approach, each individual may select those performance enhancers that work best for him or her (based on controlled studies). Acceleration protection devices are used as an example. The impact of this philosophy can be readily seen in human factor design strategy as well as in the interpretation of human research data.

Pediatric interhospital critical care transport: consensus of a national leadership conference

As pediatric interhospital critical care transport has evolved toward a distinct discipline, practitioners in this field have recognized the need for guidelines for transport program development and patient care. At a gathering of medical directors of pediatric transport programs, the following topics were discussed: team composition and transport staffing, training requirements for pediatric and nonpediatric transport teams, goals and design of a transport data base, and medical-legal issues, including the responsibilities of the referring and receiving institutions. Consensus recommendations were made for the major issues in each of these areas. Several questions were raised which may be answered by multiinstitutional studies.

A study of techniques for the distribution of oral rabies vaccine to wild raccoon populations

This study evaluates a technique for delivering an oral rabies vaccine to wild raccoon (Procyon lotor) populations. Various baits and attractants were first tested on caged raccoons and baiting trials were then conducted in two distinct physiographic regions of Virginia (USA), the coastal plain and the Piedmont plateau. Raccoon population density studies preceded the field trials. Each polyurethane sponge bait distributed contained approximately 200 mg tetracycline as a tissue biomarker, and was presented in an outer bag with a fish-based attractant. Baits were frozen until used and distributed from an aeroplane throughout two 4-km2 sites in each region. One site received 450 baits/km2 and the other 120 baits/km2. Postbaiting evaluation included the direct observation of baits in the field and the examination of teeth and bone from trapped and hunted animals for evidence of the biomarker. Between 30% and 73% of the captured animals showed evidence of bait consumption. The proportion of animals with evidence of bait uptake changed when areas adjacent to the actual baiting site were included. The percentage of animals taking baits was not related to the density of baits that were distributed.

Tryptophan metabolism in children with attentional deficit disorder

The authors present the first report, to their knowledge, of hyperserotonemia in children with attentional deficit disorder who had normal intelligence. Hyperserotonemic children had significantly lower levels of plasma total and protein-bound tryptophan and a higher percentage of free tryptophan than those with normal serotonin levels. Plasma kynurenine did not differ, suggesting that the hyperserotonemia is not due to a blockade of the kynurenine pathway but may reflect on increase in tissue tryptophan uptake and use.