Estimating Queen Conch (Strombus gigas) home ranges using acoustic telemetry: implications for the design of marine fishery reserves

Marine reserves (MRs) may function as a vital tool in the conservation and management of marine resources if source populations are managed for the benefit of those downstream. Consequently, it is critical to evaluate the home range of marine animals to ensure that MRs are large enough to protect source populations. We used acoustic telemetry to study movements of adult queen conch (Strombus gigas) within aggregations at two sites in the Florida Keys from June 1997 through July 1998. A total of 68 conch were tagged and tracked for up to one year. Latitude and longitude of each conch were recorded biweekly and data used to estimate the minimum speed, degree of site fidelity, and home range of each animal. Conch showed significantly greater displacement/ time during the summer. There were no significant differences in movement rate, site fidelity, or size of home range between males and females. Mean home range was 5.98 ha. Based on estimated home ranges of the aggregations, the size and location of the existing reserves at these two sites were inadequate to protect the conch aggregations should the fishery reopen

Troponins, Acute Coronary Syndrome and Renal Disease: From Acute Kidney Injury Through End-stage Kidney Disease

The diagnosis of acute coronary syndromes (ACS) is heavily dependent on cardiac biomarker assays, particularly cardiac troponins. ACS, particularly non-ST segment elevation MI, are more common in patients with acute kidney injury, chronic kidney disease (CKD) and end-stage kidney disease (ESKD), are associated with worse outcomes than in patients without kidney disease and are often difficult to diagnose and treat. Hence, early accurate diagnosis of ACS in kidney disease patients is important using easily available tools, such as cardiac troponins. However, the diagnostic reliability of cardiac troponins has been suboptimal in patients with kidney disease due to possible decreased clearance of troponin with acute and chronic kidney impairment and low levels of troponin secretion due to concomitant cardiac muscle injury related to left ventricular hypertrophy, inflammation and fibrosis. This article reviews the metabolism and utility of cardiac biomarkers in patients with acute and chronic kidney diseases. Cardiac troponins are small peptides that accumulate in both acute and chronic kidney diseases due to impaired excretion. Hence, troponin concentrations rise and fall with acute kidney injury and its recovery, limiting their use in the diagnosis of ACS. Troponin concentrations are chronically elevated in CKD and ESKD, are associated with poor prognosis and decrease the sensitivity and specificity for diagnosis of ACS. Yet, the evidence indicates that the use of high-sensitivity troponins can confirm or exclude a diagnosis of ACS in the emergency room in a significant proportion of kidney disease patients; those patients in whom the results are equivocal may need longer in-hospital assessment

A new outlook towards kidney injuries

Acute and chronic progression of injury to the kidney leads to the failure of the renal system and has become an increasingly important cause of morbidity and mortality. Present diagnosis detects the condition only after irreversible loss of 70 percent of kidney function. Current research is focused only on the clinical manifestations after the kidney injuries and not towards the exact cause of the condition. Here we propose a new outlook- that there is an involvement of a pathogen in the pathogenesis of kidney injuries. Basis for our proposal is given by the similarity of the pathogenesis events occurring between a classical example of hepatitis and kidney injuries. Furthermore, literature regarding the role of early kidney injury biomarkers in innate immunity indicates the involvement of the pathogen. Research in this theme possesses a strong possibility in the development of therapeutic, preventive and management strategies for the acute and chronic kidney injuries

An observational cohort feasibility study to identify microvesicle and miRNA biomarkers of acute kidney injury following paediatric cardiac surgery

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Objectives: Micro-RNA, small noncoding RNA fragments involved in gene regulation, and microvesicles, membrane-bound particles less than 1 μm known to regulate cellular processes including responses to injury, may serve as disease-specific biomarkers of acute kidney injury. We evaluated the feasibility of measuring these signals as well as other known acute kidney injury biomarkers in a mixed pediatric cardiac surgery population. Design: Single center prospective cohort feasibility study. Setting: PICU. Patients: Twenty-four children (≤ 17 yr) undergoing cardiac surgery with cardiopulmonary bypass without preexisting inflammatory state, acute kidney injury, or extracorporeal life support. Interventions: None. Measurements and Main Results: Acute kidney injury was defined according to modified Kidney Diseases Improving Global Outcomes criteria. Blood and urine samples were collected preoperatively and at 6–12 and 24 hours. Microvesicles derivation was assessed using flow cytometry and NanoSight analysis. Micro-RNAs were isolated from plasma and analyzed by microarray and quantitative real-time polymerase chain reaction. Data completeness for the primary outcomes was 100%. Patients with acute kidney injury (n = 14/24) were younger, underwent longer cardiopulmonary bypass, and required greater inotrope support. Acute kidney injury subjects had different fractional content of platelets and endothelial-derived microvesicles before surgery. Platelets and endothelial microvesicles levels were higher in acute kidney injury patients. A number of micro-RNA species were differentially expressed in acute kidney injury patients. Pathway analysis of candidate target genes in the kidney suggested that the most often affected pathways were phosphatase and tensin homolog and signal transducer and activator of transcription 3 signaling. Conclusions: Microvesicles and micro-RNAs expression patterns in pediatric cardiac surgery patients can be measured in children and potentially serve as tools for stratification of patients at risk of acute kidney injury

Life on the list: an exploratory study of the life world of individuals waiting for a kidney transplant

Kidney transplantation is the treatment of choice for many individuals with end stage renal disease (ESRD), as transplantation is reported to offer a greater quality of life than renal dialysis. At the end of March 2008 there were 6980 people on the active transplant list for kidney or kidney and pancreas transplants. However, during the previous year a total of 1453 deceased donor kidney transplants were carried out1, illustrating the mismatch between demand for and availability of kidneys for transplant. Whilst the Government has pledged to improve transplant services and to address the organ shortage, individuals on the kidney transplant list are currently facing an average wait of more than two years. Individuals waiting for a kidney transplant face complex challenges, which are currently poorly researched. An insight into the experience of waiting for a kidney transplant and how individuals interpret that wait could contribute to clinical knowledge and lead to improved support for these individuals. It could also raise public awareness about the issues involved in waiting for a kidney transplant, potentially encouraging donatio

Phenotype standardization for drug-induced kidney disease.

Drug-induced kidney disease is a frequent cause of renal dysfunction; however, there are no standards to identify and characterize the spectrum of these disorders. We convened a panel of international, adult and pediatric, nephrologists and pharmacists to develop standardized phenotypes for drug-induced kidney disease as part of the phenotype standardization project initiated by the International Serious Adverse Events Consortium. We propose four phenotypes of drug-induced kidney disease based on clinical presentation: acute kidney injury, glomerular, tubular, and nephrolithiasis, along with the primary and secondary clinical criteria to support the phenotype definition, and a time course based on the KDIGO/AKIN definitions of acute kidney injury, acute kidney disease, and chronic kidney disease. Establishing causality in drug-induced kidney disease is challenging and requires knowledge of the biological plausibility for the specific drug, mechanism of injury, time course, and assessment of competing risk factors. These phenotypes provide a consistent framework for clinicians, investigators, industry, and regulatory agencies to evaluate drug nephrotoxicity across various settings. We believe that this is the first step to recognizing drug-induced kidney disease and developing strategies to prevent and manage this condition

A Primer on Kidney Transplantation: Anatomy of the Shortage

Kidneys are unique among the solid organs due to the combination of the low risk of living donation, the feasibility of sustaining life on dialysis for several years following kidney failure, and Medicare coverage of dialysis and transplantation for kidney patients. Despite these advantages, thousands of Americans die each year while waiting for a kidney transplant, and the waiting list grows each year. In this kidney transplantation primer, we provide a quantitative description of the kidney shortage and discuss future trends and possible solutions. We demonstrate that the current system provides only about half as many kidneys as are needed for transplantation and the gap cannot be eliminated through an increase in deceased donation alone, because most kidneys from suitable deceased donors are already procured. The prospects for increasing living donations under the current system are also dim. Donations from living kidney donors have declined from their 2003 peak and nearly all living kidney donations are directed by the donor, usually to family members, rendering the current account of living kidney donation as “altruistic” somewhat misleading. For all of these reasons, we believe the time is ripe to reconsider financial incentives for kidney donation. Needless to say, a system that provided financial rewards for living donors could produce unsavory consequences, and would have to be carefully designed and managed. But without such a system, the most likely version of the future is a continuation of unnecessarily high rates of death and disability from kidney failure

Diabetic microangiopathy in Type 1 (insulin-dependent) diabetic patients after successful pancreatic and kidney or solitary kidney transplantation

To evaluate the beneficial effect of pancreatic grafting on peripheral microcirculation and long-term clinical outcome, we compared data of 28 Type 1 (insulin-dependent) diabetic patients either given a pancreatic and kidney graft simultaneously or given a solitary kidney graft (n=17). Peripheral microcirculation was estimated by transcutaneous oxygen pressure measurement (including reoxygenation potential after blood flow occlusion) and erythrocyte flow / velocity by a non-contact laser speckle method. All the measured parameters showed significant differences between diabetic and control subjects in the mean follow-up time of 49 (simultaneous pancreas and kidney transplantation) and 43 (solitary kidney transplantation) months. The data from patients after simultaneous pancreas and kidney transplantation revealed an improvement of transcutaneous oxygen pressure measurement (rise from 46±2 mm Hg to 63±3 mmHg), reoxygenation time (fall from 224±12s to 114±6s) and laser speckle measurement (rise from 4.2±1.7 to 5.6±1.8 relative units). The control group with solitary kidney transplantation did not show a positive evaluation. Data from patients after simultaneous pancreas and kidney transplantation revealed an improvement in transcutaneous oxygen pressure measurement, reoxygenation time and laser speckle measurement whereas the control group with solitary kidney transplantation did not show a positive evaluation. Improved microcirculation was more pronounced in patients with better microvascular preconditions. The results confirm that diabetic microangiopathy is positively influenced by pancreatic transplantation

Climate change and the kidney

The worldwide increase in temperature has resulted in a marked increase in heat waves (heat extremes) that carries a markedly increased risk for morbidity and mortality. The kidney has a unique role not only in protecting the host from heat and dehydration but also is an important site of heat-associated disease. Here we review the potential impact of global warming and heat extremes on kidney diseases. High temperatures can result in increased core temperatures, dehydration, and blood hyperosmolality. Heatstroke (both clinical and subclinical whole-body hyperthermia) may have a major role in causing both acute kidney disease, leading to increased risk of acute kidney injury from rhabdomyolysis, or heat-induced inflammatory injury to the kidney. Recurrent heat and dehydration can result in chronic kidney disease (CKD) in animals and theoretically plays a role in epidemics of CKD developing in hot regions of the world where workers are exposed to extreme heat. Heat stress and dehydration also has a role in kidney stone formation, and poor hydration habits may increase the risk for recurrent urinary tract infections. The resultant social and economic consequences include disability and loss of productivity and employment. Given the rise in world temperatures, there is a major need to better understand how heat stress can induce kidney disease, how best to provide adequate hydration, and ways to reduce the negative effects of chronic heat exposure.Published versio