Health assessment of the pink land iguana, Conolophus marthae.

The pink land iguana, Conolophus marthae, is one of four species of iguanas (three terrestrial and one marine) in the Galápagos Islands, and the only one listed as critically endangered by the IUCN. The species can only be found on the north-west slopes of the highest volcano on the island of Isabela and was first described to science in 2009. As part of a population radio and satellite telemetry monitoring study, a health assessment was authorized by the Galápagos National Park. Wild adult iguanas were captured on Wolf Volcano in September 2019 and April 2021 to record morphological and physiological parameters including body temperature, heart rate, body measurements, intraocular pressures, tear formation, and infrared iris images. Blood samples were also collected and analyzed. An i-STAT portable blood analyzer was used to obtain values for base excess in the extracellular fluid compartment (BEECF), glucose, hematocrit, hemoglobin, ionized calcium (iCa), partial pressure of carbon dioxide (pCO 2 ), partial pressure of oxygen (pO 2 ) , percent oxygen saturation (sO 2 %), pH, potassium (K), and sodium (Na). Standard laboratory hematology techniques were employed for packed-cell-volume (PCV) determination. When possible, data were compared to previously published and available data for the other Galápagos iguanas. The results reported here provide baseline values that may be useful in detecting changes in health status among pink land iguanas affected by climate change, invasive species, anthropogenic threats, or natural disturbances.

The intracellular fluid compartment is smaller than commonly believed when measured by whole-body bioimpedance

Objectives To report our data on the total body water (TBW), intracellular volume (ICV), extracellular volume (ECV), and fat-free mass (FFM) from studies using whole-body bioimpedance (BIA) with the aim of contrasting them to commonly cited reference values. Methods Data were retrospectively retrieved from three single-center studies of adult healthy male volunteers and one study of women scheduled for abdominal hysterectomy where multifrequency BIA had been applied to obtain measurements of TBW, ICV, ECV, and FFM. Results Based on measurements performed in 44 males, the TBW, ICV, ECV, and FFM represented 49.1 (4.9)%, 23.32 (3.1)%, 25.8 (2.2)%, and 67.4 (7.4)% of the BW, respectively (mean, SD). In 15 females, these volumes were 40.4 (4.5)%, 18.0 (2.1)%, 22.4 (2.6)%, and 55.6 (6.1)% per kg BW, respectively. The deviation of these measurements from the reference values increased linearly with body weight and age. Conclusions Body fluid volumes indicated by BIA showed that TBW amounted to 80% of the reference volume, which is 60% per kg BW in adult males. The ratio between the ICV and the ECV was approximately 1:1, while this ratio is traditionally reported to be 2:1.

Differential assessment of fluid compartments by bioimpedance in pediatric patients with kidney diseases

Background The kidney is central for maintaining water balance. As a corollary, patients with impaired kidney function are prone to pathological fluid volumes. Total body water (TBW) is distributed between the extracellular (ECW) and intracellular fluid compartments (ICW). In clinical practice, the judgment of hydration status does not allow to distinguish between ECW and ICW. Here, we evaluate the hydration status in children with chronic kidney disease by analyzing TBW, ECW, and ICW. Methods Hydration was quantified using whole-body bioimpedance spectroscopy (BCM) in 128 outpatients (1–25 years, 52 girls). Forty-two were transplanted (TPL), 43 suffered from chronic kidney disease without kidney replacement therapy (CKD), 21 were on peritoneal dialysis (PD), and 22 on hemodialysis (HD). HD patients were investigated before, after, and sequentially during dialysis. Results The ECW and ICW values obtained by BCM were of the same magnitude as those from the literature using isotope dilution. When compared with a healthy control group, TBW was increased in 9 TPL, 9 CKD, 1 PD, and 11 HD patients before but in none after dialysis. The decline of overhydration during dialysis (p < 0.001, n = 22) correlated with the change in body weight (R2 = 0.62). The kinetics of fluid compartment changes assessed twice in six HD patients revealed a reproducible linear decay of the ECW/ICW ratio due to an increase of ICW and a decrease of ECW. Conclusion BCM quantifies TBW and acute changes of ECW and ICW in children with chronic kidney failure. The clinical utility of measuring TBW, ECW, and ICW should be defined in the future.

Postoperative management after coronary artery bypass graft surgery

Postoperative management of patients following coronary artery bypass graft surgery is focused on fast-track recovery but can be challenging, and is often characterized by haemodynamic fluctuations that may require inotropic support, fluid compartment shifts, an increased bleeding tendency, and occasional surgical complications that require urgent re-exploration. This chapter focuses primarily on haemodynamic management and the attendant indications for and choices of pharmacological therapy, as well as considering the indications for continuance or initiation of longer-term medications. Other aspects of acute care such as bleeding and coagulopathy, respiratory support and ventilation and weaning protocols, sedation, and pain control are also important to ensure a smooth transition from acute care to hospital discharge.

The secreted protein signature of hydatid fluid from pulmonary cystic echinococcosis

The vast majority of cystic echinococcosis cases in Southern Brazil are caused by Echinococcus granulosus and Echinococcus ortleppi. Comparative proteomic studies of helminths have increased the knowledge about the molecular survival strategies adopted by parasites. Here, we surveyed the protein contents of the hydatid fluid compartment of E. granulosus and E. ortleppi pulmonary bovine cysts, in an attempt to compare their molecular arsenal in this host-parasite interface. Hydatid fluid samples from three isolates of each species were analyzed by trypsin digestion and mass spectrometry. We identified 280 proteins in E. granulosus and 251 proteins in E. ortleppi, highlighting a core of 52 proteins common to all samples of hydatid fluid. The in silico functional analysis revealed important molecular functions and processes active in pulmonary cystic echinococcosis. Some were more evident in one species, such as apoptosis in E. ortleppi, and cysteine protease activity in E. granulosus, while many molecular activities have been found in fluids of both species, such as proteolysis, development signaling and extracellular structures organization. The similar molecular tools employed by E. granulosus and E. ortleppi for their survival within the host are potential targets for new therapeutic approaches to deal with cystic echinococcosis and other larval cestodiases.

Neoplastic meningitis: metastases to the leptomeninges and cerebrospinal fluid

Carcinomatous meningitis or meningeal carcinomatosis is a term that defines leptomeningeal metastases arising as a result of metastases from systemic solid cancers. Similarly, lymphomatous and leukaemic meningitis result from cerebrospinal fluid dissemination of lymphoma or leukaemia. All three entities are commonly referred to as neoplastic meningitis or leptomeningeal metastases due to involvement of both the cerebrospinal fluid compartment as well as the leptomeninges comprised of the pia and arachnoid. Treatment options are limited for these neurological complications and outcomes are generally poor. New therapeutic strategies are desperately needed as more cancer patients survive longer and are at increased risk for neoplastic meningitis.

Fluid and electrolyte physiology in anaesthetic practice

The maintenance of body fluid homeostasis is an essential task in perioperative care. Body fluid volumes are tightly controlled by the nervous system, by hormones, and by the kidneys. All these systems are affected by anaesthesia and surgery in ways that must be appreciated by the anaesthetist. Administration of infusion fluids is the key tool to prevent major derangements of the body fluid volumes during before, during, and after surgery. By varying its composition, an infusion fluid can be made to selectively expand or shrink a body fluid compartment. The total osmolality determines whether the infused volume distributes over the total body water or over the extracellular fluid volume, or even attracts fluid from intracellular space. Infusion fluid is the first-line tool in the management of the vasodilation that is induced by both general and regional anaesthesia. Fluids are also an essential component in the treatment of haemorrhage, in which a reduction in arterial pressure implies that 20% of the blood volume has been lost. Capillary refill restores the blood volume, but too slowly to prevent haemorrhagic shock. In this situation, prompt intravenous fluid therapy is life-saving. Electrolyte derangements may be induced by disease and/or medication. The most essential ones to consider during anaesthesia are sodium, potassium, calcium, and bicarbonate.

Paravascular channels, cisterns, and the subarachnoid space in the rat brain: A single compartment with preferential pathways

Recent evidence suggests an extensive exchange of fluid and solutes between the subarachnoid space and the brain interstitium, involving preferential pathways along blood vessels. We studied the anatomical relations between brain vasculature, cerebrospinal fluid compartments, and paravascular spaces in male Wistar rats. A fluorescent tracer was infused into the cisterna magna, without affecting intracranial pressure. Tracer distribution was analyzed using a 3D imaging cryomicrotome, confocal microscopy, and correlative light and electron microscopy. We found a strong 3D colocalization of tracer with major arteries and veins in the subarachnoid space and large cisterns, attributed to relatively large subarachnoid space volumes around the vessels. Confocal imaging confirmed this colocalization and also revealed novel cisternal connections between the subarachnoid space and ventricles. Unlike the vessels in the subarachnoid space, penetrating arteries but not veins were surrounded by tracer. Correlative light and electron microscopy images indicated that this paravascular space was located outside of the endothelial layer in capillaries and just outside of the smooth muscle cells in arteries. In conclusion, the cerebrospinal fluid compartment, consisting of the subarachnoid space, cisterns, ventricles, and para-arteriolar spaces, forms a continuous and extensive network that surrounds and penetrates the rat brain, in which mixing may facilitate exchange between interstitial fluid and cerebrospinal fluid.