Urinary nephrin-a potential marker of early glomerular injury: a systematic review and meta-analysis.

BACKGROUND: Both early recognition of glomerular injury and diagnosis of renal injury remain important problems in clinical settings, and current diagnostic biomarkers have limitations. The aim of this review was to determine the diagnostic accuracy of urinary nephrin for detecting early glomerular injury. METHODS: A search was conducted through electronic databases for all relevant studies published until January 31, 2022. The methodological quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Pooled sensitivity, specificity, and other estimates of diagnostic accuracy were determined using a random effect model. The Summary Receiver Operating Characteristics (SROC) was used to pool the data and to estimate the area under the curve (AUC). RESULTS: The meta-analysis included 15 studies involving 1587 participants. Overall, the pooled sensitivity of urinary nephrin for detecting glomerular injury was 0.86 (95% CI 0.83-0.89) and specificity was 0.73 (95% CI 0.70-0.76). The AUC-SROC to summarise the diagnostic accuracy was 0.90. As a predictor of preeclampsia, urinary nephrin showed a sensitivity of 0.78 (95% CI 0.71-0.84) and specificity of 0.79 (95% CI 0.75-0.82), and as a predictor of nephropathy the sensitivity was 0.90 (95% CI 0.87-0.93), and specificity was 0.62 (95% CI 0.56-0.67). A subgroup analysis using ELISA as a method of diagnosis showed a sensitivity of 0.89 (95% CI 0.86-0.92), and a specificity of 0.72 (95% CI 0.69-0.75). CONCLUSION: Urinary nephrin may be a promising marker for the detection of early glomerular injury. ELISA assays appear to provide reasonable sensitivity and specificity. Once translated into clinical practice, urinary nephrin could provide an important addition to a panel of novel markers to help in the detection of acute and chronic renal injury.

Optimization of a non-activating medium for short-term chilled storage of barramundi (Lates calcarifer) testicular spermatozoa.

Reliable short-term chilled sperm storage is a critical prerequisite to using advanced reproductive techniques for captive breeding of barramundi (Asian sea bass; Lates calcarifer). Marine Ringer's solution (MRS) is a common non-activating medium (NAM) and has previously been used to store sperm from wild-caught barramundi. However, MRS-stored spermatozoa from captive-bred barramundi were observed to lyse within 30 min incubation. Therefore, this study aimed to optimize the composition of NAM for short-term chilled storage by characterizing and mimicking the biochemical profile of seminal and blood plasma of captive-bred barramundi. To further understand the effect of each component, osmolality was first examined to determine its effect on sperm viability. Thereafter, the effects of NaHCO3, pH, and Na+ and K+ concentrations on sperm motility were investigated. Optimization of the NAM formula was achieved through iterative adaptions. The increase in NAM osmolality from 260 to 400 mOsm/kg led to a significant improvement in sperm viability. Moreover, using HEPES instead of NaHCO3 as buffering agent significantly enhanced sperm motility and velocity. As a result, sperm samples diluted with optimized NAM (185 mM NaCl, 5.1 mM KCl, 1.6 mM CaCl2·2H2O, 1.1 mM MgSO4·7H2O, 10.0 mM HEPES, 5.6 mM D+ glucose, 400 mOsm/kg, pH 7.4) and stored at 4 °C showed no significant loss in total motility for up to 48 h and retained progressive motility for up to 72 h. The optimized NAM developed in this study significantly extended the functional lifespan of spermatozoa during chilled storage, permitting the ongoing development of advanced reproductive technologies for barramundi.

Kidney growth following preterm birth: evaluation with renal parenchyma ultrasonography.

BACKGROUND: Preterm birth impairs nephrogenesis, leading to a reduced nephron endowment which is inextricably linked to hypertension and chronic kidney disease in adults. The aim of this study was to compare nephron endowment between preterm infants to that of intrauterine fetuses at the same gestational age (GA) using a novel indirect ultrasound measurement of the renal parenchymal thickness. We hypothesized that extrauterine and intrauterine renal parenchymal thickness would differ based on altered renal growth environments. METHODS: In this observational study, appropriately grown preterm infants (birth weight of between the 5th and 95th percentile) born <32 weeks, admitted to the neonatal department were eligible to participate. Renal parenchymal thickness of the infants was measured at 32- and 37-weeks postmenstrual age (PMA). These measurements were compared to the intrauterine renal parenchymal thickness of appropriately grown fetuses (control). RESULTS: At 32-weeks PMA, the preterm infants had a significantly thinner renal parenchyma compared to fetuses at 32-weeks GA suggesting they had less nephrons, however by 37-weeks there was no significant difference in renal parenchymal thickness. CONCLUSIONS: We propose that the differences in the extrauterine growth of the renal parenchyma in preterm infants may be due to a reduced number of nephrons and compensatory hyperfiltration. IMPACT: This article provides insight into the effects of prematurity on nephrogenesis by comparing extrauterine renal parenchymal growth of born preterm infants to the ideal intrauterine fetal growth. Renal parenchyma thickness measurement using ultrasonography is a novel non-invasive measurement of renal development for the determination of nephron endowment. Differences in the renal parenchymal thickness of the preterm infants may be due to a deficit in nephron number and compensatory hyperfiltration.

Exploring the long-term colonisation and persistence of probiotic-prophylaxis species on the gut microbiome of preterm infants: a pilot study.

Preterm infants suffer from a higher incidence of acute diseases such as necrotising enterocolitis and sepsis. This risk can be mitigated through probiotic prophylaxis during admission. This reduction in risk is likely the result of acute modulation of the gut microbiome induced by probiotic species, which has been observed to occur up until discharge. We aimed to determine if this modulation, and the associated probiotic species, persisted beyond discharge. We conducted both a cross-sectional analysis (n = 18), at ~ 18 months of age, and a longitudinal analysis (n = 6), from admission to 18 months of the gut microbiome of preterm infants using both shotgun metagenomics and 16S rRNA profiling respectively. The 16S amplicon sequencing revealed that the microbial composition of the probiotic-supplemented infants changed dramatically over time, stabilising at discharge. However, species from the probiotic Infloran®, as well as positive modulatory effects previously associated with supplementation, do not appear to persist beyond discharge and once prophylaxis has stopped.    Conclusions: Although differences exist between supplemented and non-supplemented groups, the implications of these differences remain unclear. Additionally, despite a lack of long-term colonisation, the presence of probiotics during early neonatal life may still have modulatory effects on the microbiome assembly and immune system training. What is Known: • Evidence suggests modulation of the microbiome occurs during probiotic prophylaxis, which may support key taxa that exert positive immunological benefits. • Some evidence suggests that this modulation can persist post-prophylaxis. What is New: • We present support for long-term modulation in association with probiotic prophylaxis in a cohort of infants from North Queensland Australia. • We also observed limited persistence of the probiotic species post-discharge.

Allostatic load and systemic comorbidities in psychiatric disorders.

Psychiatric disorders are complex, disabling, and chronic conditions that are often accompanied by one or more systemic medical comorbidities. In this narrative review, we provide an overview of the allostatic load concept, which represents a multi-system dysregulation in response to chronic stress and link it to systemic comorbidities associated with psychiatric disorders. We synthesized published literature gathered using Medline (Ovid), Scopus, and PsychInfo and identified a high frequency of systemic comorbidities for both mood and psychotic disorders. The identified cardiovascular, metabolic, and immune comorbidities may represent the result of chronic wear and tear caused by a complex interaction between chronic psychosocial stress, health risk behaviors, pharmacological stressors, and the biological systems involved in the development of allostatic load. These findings support the notion that psychiatric disorders should be re-conceptualized as systemic disorders, affecting the brain and systemic biological pathways in an interconnected fashion to result in systemic comorbidities. We suggest that the multi-systemic and multi-dimensional approach that drives the allostatic load concept should be considered for understanding comorbidities in vulnerable psychiatric patients.

To Probiotic or Not to Probiotic: A Metagenomic Comparison of the Discharge Gut Microbiome of Infants Supplemented With Probiotics in NICU and Those Who Are Not.

Background: Preterm birth is associated with the development of both acute and chronic disease, and the disruption of normal gut microbiome development. Recent studies have sought to both characterize and understand the links between disease and the microbiome. Probiotic treatment may correct for these microbial imbalances and, in turn, mitigate disease. However, the criteria for probiotic supplementation in NICU's in North Queensland, Australia limits its usage to the most premature (<32 weeks gestation) and small for gestational age infants (<1,500 g). Here we use a combination of amplicon and shotgun metagenomic sequencing to compare the gut microbiome of infants who fulfill the criteria for probiotic-treatment and those who do not. The aims of this study were to determine if probiotic-supplemented preterm infants have significantly different taxonomic and functional profiles when compared to non-supplemented preterm infants at discharge. Methods: Preterm infants were recruited in North Queensland, Australia, with fecal samples collected just prior to discharge (36 ± 0.5 weeks gestation), to capture potential changes that could be probiotic induced. All samples underwent 16S rRNA gene amplicon sequencing, with a subset also used for shotgun metagenomics. Mixed effects models were used to assess the effect of probiotics on alpha diversity, beta diversity and taxonomic abundance, whilst accounting for other known covariates. Results: Mixed effects modeling demonstrated that probiotic treatment had a significant effect on overall community composition (beta diversity), characterized by greater alpha diversity and differing abundances of several taxa, including Bifidobacterium and Lactobacillus, in supplemented infants. Conclusion: Late preterm-infants who go without probiotic-supplementation may be missing out on stabilizing-effects provided through increased alpha diversity and the presence of commensal microbes, via the use of probiotic-treatment. These findings suggest that late-preterm infants may benefit from probiotic supplementation. More research is needed to both understand the consequences of the differences observed and the long-term effects of this probiotic-treatment.

Fetal renal artery blood flow - Normal ranges.

INTRODUCTION: The study objectives were to develop standard charts for fetal renal artery blood flow to define normal ranges and to assess the reliability of the measurements. METHODS: This prospective, longitudinal study reviewed 72 low-risk singleton pregnancies who had serial ultrasound examinations. Pulse wave Doppler was used to obtain the resistivity and pulsatility indices of the fetal renal arteries. Standard charts of the fetal renal arteries were created using mixed effects modelling and the intra- and interobserver reliability for the renal blood flow measurements was analysed. RESULTS: Standard charts of the normal ranges of the renal artery resistive index (RI) and pulsatility index (PI) of the fetal renal arteries were created. The 3rd, 5th, 10th, 50th, 90th, 95th and 97th centiles were calculated. The intraclass correlation coefficient was acceptable for intraobserver reliability (RI = 0.66, PI = 0.88) and poor for interobserver reliability (RI = 0.11, PI = -0.56). CONCLUSIONS: These novel charts demonstrate the change of the fetal renal artery blood flow during pregnancy. These may be used in clinical practice to detect variations from these normal ranges and be useful in future studies of kidney function projection.

Haematological and biochemical reference intervals for wild green turtles (Chelonia mydas): a Bayesian approach for small sample sizes.

Animal health is directly linked to population viability, which may be impacted by anthropogenic disturbances and diseases. Reference intervals (RIs) for haematology and blood biochemistry are essential tools for the assessment of animal health. However, establishing and interpreting robust RIs for threatened species is often challenged by small sample sizes. Bayesian predictive modelling is well suited to sample size limitations, accounting for individual variation and interactions between influencing variables. We aimed to derive baseline RIs for green turtles (Chelonia mydas) across two foraging aggregations in North Queensland, Australia, using Bayesian generalized linear mixed-effects models (n = 97). The predicted RIs were contained within previously published values and had narrower credible intervals. Most analytes did not vary significantly with foraging ground (76%, 22/29), body mass (86%, 25/29) or curved carapace length (83%, 24/29). Length and body mass effects were found for eosinophils, heterophil:lymphocyte ratio, alkaline phosphatase, aspartate transaminase and urea. Significant differences between foraging grounds were found for albumin, cholesterol, potassium, total protein, triglycerides, uric acid and calcium:phosphorus ratio. We provide derived RIs for foraging green turtles, which will be helpful in future population health assessments and conservation efforts. Future RI studies on threatened species would benefit from adapting established veterinary and biomedical standards.

The bacterial gut microbiome of probiotic-treated very-preterm infants: changes from admission to discharge.

BACKGROUND: Preterm birth is associated with the development of acute and chronic disease, potentially, through the disruption of normal gut microbiome development. Probiotics may correct for microbial imbalances and mitigate disease risk. Here, we used amplicon sequencing to characterise the gut microbiome of probiotic-treated premature infants. We aimed to identify and understand variation in bacterial gut flora from admission to discharge and in association with clinical variables. METHODS: Infants born <32 weeks gestation and <1500 g, and who received probiotic treatment, were recruited in North Queensland Australia. Meconium and faecal samples were collected at admission and discharge. All samples underwent 16S rRNA short amplicon sequencing, and subsequently, a combination of univariate and multivariate analyses. RESULTS: 71 admission and 63 discharge samples were collected. Univariate analyses showed significant changes in the gut flora from admission to discharge. Mixed-effects modelling showed significantly lower alpha diversity in infants diagnosed with either sepsis or retinopathy of prematurity (ROP) and those fed formula. In addition, chorioamnionitis, preeclampsia, sepsis, necrotising enterocolitis and ROP were also all associated with the differential abundance of several taxa. CONCLUSIONS: The lower microbial diversity seen in infants with diagnosed disorders or formula-fed, as well as differing abundances of several taxa across multiple variables, highlights the role of the microbiome in the development of health and disease. This study supports the need for promoting healthy microbiome development in preterm neonates. IMPACT: Low diversity and differing taxonomic abundances in preterm gut microbiota demonstrated in formula-fed infants and those identified with postnatal conditions, as well as differences in taxonomy associated with preeclampsia and chorioamnionitis, reinforcing the association of the microbiome composition changes due to maternal and infant disease. The largest study exploring an association between the preterm infant microbiome and ROP. A novel association between the preterm infant gut microbiome and preeclampsia in a unique cohort of very-premature probiotic-supplemented infants.

Childhood adversity, allostatic load, and adult mental health: Study protocol using the Avon Longitudinal Study of Parents and Children birth cohort.

Introduction: The cumulative burden of chronic stress and life events has been termed allostatic load. Elevated allostatic load indices are associated with different mental health conditions in adulthood. To date, however, the association between elevated allostatic load in childhood and later development of mental health conditions has not been investigated. Methods: Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we will calculate allostatic load indices using biomarkers representing the cardiovascular, metabolic, immune, and neuroendocrine systems, at the ages of 9 and 17 years. Bivariate and multivariable logistic regression models will be used to investigate the association between allostatic load and psychiatric disorders in adulthood. Furthermore, the role of adverse childhood experiences as a modifier will be investigated. Discussion: This protocol describes a strategy for investigating the association between elevated allostatic load indices in childhood at the age of 9 years old and psychiatric disorders in adulthood at 24 years old.

Is peripartum maternal fever alone a reliable predictor of neonatal sepsis? A single-centre, retrospective cohort study.

AIM: To determine the incidence rate of early-onset neonatal sepsis (EONS) among term neonates (gestation greater than 37 weeks) admitted to the neonatal intensive care unit for suspected sepsis and the association of EONS with maternal fever (temperature greater than 38°C). METHODS: A single-centre retrospective cohort study of all term neonates (gestation >37 weeks) admitted to and treated in the neonatal unit at the Townsville University Hospital between March 2015 and March 2020. Neonatal sepsis was confirmed with positive neonatal blood culture. Data on neonatal birth/stay and maternal pregnancy were collected from the electronic medical records and neonatal database. RESULTS: Data from 737 neonates who were admitted for treatment of EONS were analysed. Sixty % (426) reported maternal intrapartum fever, with 1.1% (5) of neonates developing blood culture-proven sepsis. Forty % did not report intrapartum fever (311), with 3% (9) of neonates developing sepsis. As such, the sensitivity and specificity of maternal fever are 1.14% and 97%, respectively. The positive predictive value was 35.7%, and the negative predictive value was 40.1%. Fourteen neonates developed EONS, and all of them were symptomatic. Seventy-eight % (334/426) of the women in the febrile group received epidural analgesia compared to 5% (16/311) in the afebrile group. Of the 95 neonates born to women with chorioamnionitis, one (1.0%) of the neonates born to women with chorioamnionitis developed sepsis. CONCLUSIONS: Intrapartum maternal fever is an unreliable predictor for EONS and leads to unnecessary antibiotic treatment. Symptoms in the neonate are a more reliable indicator of an ill neonate with blood culture-proven sepsis.

Methods for exploring the faecal microbiome of premature infants: a review.

The premature infant gut microbiome plays an important part in infant health and development, and recognition of the implications of microbial dysbiosis in premature infants has prompted significant research into these issues. The approaches to designing investigations into microbial populations are many and varied, each with its own benefits and limitations. The technique used can influence results, contributing to heterogeneity across studies. This review aimed to describe the most common techniques used in researching the preterm infant microbiome, detailing their various limitations. The objective was to provide those entering the field with a broad understanding of available methodologies, so that the likely effects of their use can be factored into literature interpretation and future study design. We found that although many techniques are used for characterising the premature infant microbiome, 16S rRNA short amplicon sequencing is the most common. 16S rRNA short amplicon sequencing has several benefits, including high accuracy, discoverability and high throughput capacity. However, this technique has limitations. Each stage of the protocol offers opportunities for the injection of bias. Bias can contribute to variability between studies using 16S rRNA high throughout sequencing. Thus, we recommend that the interpretation of previous results and future study design be given careful consideration.

Can measurement of the foetal renal parenchymal thickness with ultrasound be used as an indirect measure of nephron number?

Chronic kidney disease continues to be under recognised and is associated with a significant global health burden and costs. An adverse intrauterine environment may result in a depleted nephron number and an increased risk of chronic kidney disease. Antenatal ultrasound was used to measure the foetal renal parenchymal thickness (RPT), as a novel method to estimate nephron number. Foetal renal artery blood flow was also assessed. This prospective, longitudinal study evaluated the foetal kidneys of 102 appropriately grown and 30 foetal growth-restricted foetuses between 20 and 37 weeks gestational age (GA) to provide vital knowledge on the influences foetal growth restriction has on the developing kidneys. The foetal RPT and renal artery blood flow were measured at least every 4 weeks using ultrasound. The RPT was found to be significantly thinner in growth-restricted foetuses compared to appropriately grown foetuses [likelihood ratio (LR) = 21.06, P ≤ 0.0001] and the difference increases with GA. In foetuses with the same head circumference, a growth-restricted foetus was more likely to have a thinner parenchyma than an appropriately grown foetus (LR = 8.9, P = 0.0028), supporting the principle that growth-restricted foetuses preferentially shunt blood towards the brain. No significant difference was seen in the renal arteries between appropriately grown and growth-restricted foetuses. Measurement of the RPT appears to be a more sensitive measure than current methods. It has the potential to identify infants with a possible reduced nephron endowment allowing for monitoring and interventions to be focused on individuals at a higher risk of developing future hypertension and chronic kidney disease.

Cystatin C: A more reliable biomarker of renal function in young infants? A longitudinal cohort study.

AIM: We carried out a longitudinal cohort study to measure serial CysC (Cystatin C) in a cohort of neonates born preterm until the age of 2 years. We hypothesised that CysC levels are independent of body weight and would not vary with gestational age. METHODS: This prospective cohort study was conducted from August 2014 until October 2016, and follow-up was completed in October 2018. Preterm infants at less than 28 weeks of gestation (extremely preterm infants) were recruited and followed up until the age of 24 months. Blood samples for measurement of CysC were collected at regular intervals. RESULTS: We recruited 58 preterm neonates with mean gestation was 26.2 (1.5) weeks, and a mean birth weight was 917 (140) g. One-way analysis of variance (ANOVA) did not show any significant difference in CysC levels between 28, 32 and 37 weeks' gestation (P = .09) despite a significant increase in body weight (P < .001). The mean CysC level was higher in the neonatal period and subsequently plateaued by 24 months. CONCLUSION: Serum CysC level is independent of body weight and not influenced by postnatal age nor by gender.

The effect of diabetes during pregnancy on fetal renal parenchymal growth.

AIMS/HYPOTHESIS: Diabetes in pregnancy is thought to adversely affect the developing fetal kidneys. The rate of gestational diabetes is increasing globally with major consequences for future renal function. Very little is known about the impact of hyperglycaemia on the fetal renal parenchyma which contains the developing nephrons. The aim of this study was to measure the fetal renal parenchymal thickness and evaluate whether diabetes during pregnancy affects the growth of the fetal kidneys. METHODS: This prospective, observational study used serial ultrasound measurements to evaluate the fetal renal parenchymal growth of 55 pregnancies with diabetes compared to 72 control pregnancies. Mixed effects modelling was used to analyse the data. RESULTS: The renal parenchyma of fetuses from mothers with gestational diabetes was significantly thicker than those from the control group (LR Chisq = 4.8, df = 1, p = 0.029), however, the difference was proportional to the larger size of these fetuses. Fetuses of pregestational diabetics demonstrated no significant difference in renal parenchymal thickness compared to the control group even though they were also larger fetuses. Parenchymal growth slowed with increasing abdominal circumference in the pregestational diabetic group, suggesting an adverse effect on nephrogenesis, however this did not reach statistical significance. CONCLUSIONS/INTERPRETATION: Our study provides unique data on how diabetes during pregnancy influences fetal kidney growth. Appropriate management of diabetic pregnancies may mitigate some of the adverse effects on the fetal kidneys. Increasing degrees of hyperglycaemia, as seen sometimes in pregestational diabetes, may affect nephrogenesis; however larger studies are needed.

An evaluation of preterm kidney size and function over the first two years of life.

BACKGROUND: We carried out a study to determine the impact of prematurity on kidney development in the first 2 years of life. METHODS: In this prospective study, extremely preterm neonates (gestation < 28 weeks) were recruited and underwent assessments at 6, 12, and 24 months of age. A cohort of neonates born term were also recruited and followed up for 24 months. The primary outcomes measured in this study were total kidney volume (TKV) and estimated glomerular filtration rate (eGFR); albuminuria and blood pressure measurements (all provided as mean (standard deviation)) were the secondary outcomes. RESULTS: Fifty-three premature and 31 term neonates (control) were recruited. At the age of 24 months (corrected age), infants born preterm had significantly smaller TKV (56.1 (9.4) vs. 64.8 (10.2) mL; P = 0.006). There was no difference in eGFR. These preterm infants were smaller (11.25 (1.53) vs. 12.9 (1.8) kg; P = 0.002) and shorter (83.8 (3.0) vs. 86.3 (3.4) cm; P = 0.02) when compared with the control group. At 6, 12, and 18 months respectively, preterm infants had, relative to their height, significantly smaller kidney volumes (0.54 (0.1) vs. 0.59 (0.1) mL/cm, P = 0.05; 0.61 (0.1) vs.0.71 (0.1) mL/cm, P = 0.003; and 0.67 (0.1) vs.0.76 (0.1) mL/cm, P = 0.006). CONCLUSIONS: Relative to body length, TKV in premature infants is smaller. Since length reflects adult body proportions more accurately than BSA, TKV to height ratio may be a more important measure in the child. Despite smaller TKV (and therefore fewer nephrons), infants born prematurely achieve similar eGFRs in the first 24 months of life, probably due to single-nephron hyperfiltration.

Fetal kidney charts of a novel measurement of the renal parenchymal thickness to evaluate fetal kidney growth and potential function.

OBJECTIVE: The objective of this study was to develop new standard growth charts for fetal renal parenchymal thickness, length, and volume to define normal ranges for use in clinical practice and to assess the reliability of these measurements. METHODS: This was a prospective, longitudinal study of 72 low-risk singleton pregnancies undergoing serial ultrasound examinations at least every four weeks. Multiple renal measurements were performed on both kidneys at each scan. The renal parenchymal thickness was measured in the mid-sagittal plane. Standard charts were developed and the intra and interobserver reliability for the renal measurements was analysed. RESULTS: Standard charts were developed for fetal renal parenchymal thickness, length, and volume. CONCLUSION: We present novel charts, which demonstrate the growth of the fetal renal parenchyma during pregnancy. They will be useful in clinical practice to identify any alterations from these normal ranges, which may be an important criterion for assisting prenatal diagnosis of renal pathologies and future studies in the prediction of kidney function.

Cutaneous Lesions in Freshwater Turtles (Emydura macquarii krefftii and Myuchelys latisternum) in a Rainforest Creek in North Queensland, Australia.

Freshwater turtles inhabit most rivers and creeks on the east coast of Australia, but some species are only found in specific catchments, which makes them vulnerable to extinction. During annual fieldtrips to Alligator Creek, North Queensland, the resident population of Myuchelys latisternum and Emydura macquarii krefftii in a natural pond, just outside Bowling Green National Park, have been surveyed for a number of years and demographic data recorded against tagged turtles. Rounded, cutaneous lesions on individual animals were first noted in August 2016, three years after the first survey of the population. Turtles living in the upstream sections of the creek were not affected. An initial investigation into the cause of the lesions ruled out pollutants and although the bacterial communities appeared to be different on turtles with lesions, a causative agent was not identified. Attempts to isolate virus in culture was not successful and specific PCRs for ranavirus, papillomavirus, adenovirus and herpesvirus did not identify their presence. Blood biochemical parameters, body condition and activity levels were not significantly different between affected turtles and those without lesions. The turtles in this pond were monitored regularly over the following three years with 249 M. latisternum and 192 E. m. krefftii captured, tagged and released. The prevalence of the lesions fluctuated with season from 0 to 77 and 68% respectively, but did not vary significantly between species or sex in adults. There was a tendency for larger animals to be more likely to have lesions. The position of the lesions on the turtles was mostly on dorsal surfaces, distally on the legs and proximal on the tales of males, indicating that the initial lesion may have been associated with a behaviourally induced trauma. Recaptured animals (n = 43) during this period, provided records of lesion progression over time and while some healed up between capture events, others persisted for up to 24 months. Some turtles were repeatedly captured without lesions. Intra-species aggression associated with seasonal behaviours could potentially be the primary cause of skin trauma, followed by a secondary invasion of an unusual pathogen present in the environment.

Growth and Resorption of Chronic Subdural Hematomas: Gardner, Weir, and the Osmotic Hypothesis Revisited.

BACKGROUND: To explain why some chronic subdural hematomas (CSDHs) grow and/or resorb, a physically decreasing outer membrane (OM) surface area (SA) to CSDH volume (V) ratio has been reexplored, and a critical CSDH size inferred (OM SA ≈ V). Gardner showed that since CSDH protein exceeded cerebrospinal fluid (CSF) protein, CSF→CSDH osmosis occurred across a semipermeable inner membrane (n = 1). By contrast, Zollinger and Gross demonstrated that serum→CSDH osmosis could also occur across the OM (n = 1). Notably, Weir refuted Zollinger and Gross by finding equal CSDH and serum total protein (n = 20); however, Weir did not refute Gardner. Although all extant mechanisms, especially rehemorrhages, explain CSDH growth, only OM SA ≥ V simultaneously permits resorption. We aimed to reevaluate the osmotic hypothesis. METHODS: Paired serum and CSDH samples were measured in a prospective cohort. RESULTS: Results were consecutively obtained in 116 patients (87 men; mean age, 73 ± 13 years). Serum osmolality and CSDH osmolality were similar (285.70 ± 7.99 vs. 283.85 ± 7.52 mmol/kg, respectively; P = 0.11) and significantly correlated (r = 0.75, P < 0.0001). Serum total protein significantly exceeded CSDH total protein (66.6 ± 6.8 vs. 43.68 ± 20.24 g/L, P < 0.0001) as did serum albumin (35.62 ± 4.46 vs. 30.85 ± 8.5 g/L, P < 0.0001) and serum total globulins (31.5 ± 6 vs. 18.6 ± 11.4 g/L, P < 0.0001). Serum and CSDH proteins were not correlated (total protein: r = 0.003; albumin: r = 0.08; globulins: r = 0.21). CONCLUSIONS: Only crystalloids equilibrated. CSDH colloids were significantly decreased. CSDH dilution or colloidal flocculation is implied. CSDH dilution (by CSF→CSDH inner membrane [IM] osmosis or OM transudation/exudation) could favor CSDH growth, as would repeated OM hemorrhages. Contrariwise, isolated colloidal flocculation could favor CSDH shrinkage by OM CSDH→serum osmosis. The latter may result in OM SA ≥ V favorable for ultimate resolution. Our results refute Weir and Zollinger and Gross, but not Gardner. Osmotic gradients simultaneously exist for both CSDH growth and resorption. Each equilibrium could depend on each gradient relative to each IM/OM semipermeability.