Water Balance in Giraffes

Wild giraffes live in arid environments. Having access to water and minimizing water requirements are critical. The main sources of water are the water in browse and water generated by metabolism. Giraffes rely less on surface water: intermittent use of surface water is a legendary characteristic of giraffes. The volume of water needed depends on body mass. For a giraffe weighing 750 kg, ~25 L of water is needed daily. The water content of browse is ~60%, and as a giraffe of that mass will eat ~35 kg of fresh browse daily, it simultaneously will acquire ~20 L of water. Metabolism of the fat, carbohydrates, and proteins in 35 kg of fresh browse will produce ~10 L of water. These two sources of water exceed daily requirements and reduce the need to drink surface water. Water is lost through feces, evaporation from the skin and respiratory tract, and in urine. Fecal water loss and water lost in exhaled air amount to ~4 L daily (~2 L each). It is not known if giraffes sweat, but their skin contains active sweat glands. The volume of water lost as sweat will vary according to what thermoregulatory mechanisms are activated to minimize sweating, but may be 5 L daily. Obligatory excretion of water-soluble wastes in urine can account for most water lost daily, and that amount is related to kidney anatomy and function. In a 750-kg giraffe, obligatory urine volume is ~10 L daily.

Acute kidney injury

Assessing and supporting kidney function is an integral aspect of acute care. AKI (acute kidney injury) may cause sudden, life-threatening biochemical disturbances and hence the early identification, escalation to treatment and management of AKI is an important focus in the management of acutely ill patients. This chapter reviews kidney anatomy and physiology followed by the nursing care involved in assessing and managing abnormal kidney function. The focus is on relevance and applicability to clinical practice and understanding of kidney function as protective measures and early detection of anomalies greatly reduces the risk of acute kidney injury. Common renal pathologies are explored and the role of renal replacement therapies is discussed.

Intravascular flow stimulates PKD2 (polycystin-2) channels in endothelial cells to reduce blood pressure

PKD2 (polycystin-2, TRPP1), a TRP polycystin channel, is expressed in endothelial cells (ECs), but its physiological functions in this cell type are unclear. Here, we generated inducible, EC-specific Pkd2 knockout mice to examine vascular functions of PKD2. Data show that a broad range of intravascular flow rates stimulate EC PKD2 channels, producing vasodilation. Flow-mediated PKD2 channel activation leads to calcium influx that activates SK/IK channels and eNOS serine 1176 phosphorylation in ECs. These signaling mechanisms produce arterial hyperpolarization and vasodilation. In contrast, EC PKD2 channels do not contribute to acetylcholine-induced vasodilation, suggesting stimulus-specific function. EC-specific PKD2 knockout elevated blood pressure in mice without altering cardiac function or kidney anatomy. These data demonstrate that flow stimulates PKD2 channels in ECs, leading to SK/IK channel and eNOS activation, hyperpolarization, vasodilation and a reduction in systemic blood pressure. Thus, PKD2 channels are a major component of functional flow sensing in the vasculature.

Normal Anatomy, Histology, and Spontaneous Pathology of the Kidney, and Selected Renal Biomarker Reference Ranges in the Cynomolgus Monkey

To further our understanding of the nonhuman primate kidney anatomy, histology, and incidences of spontaneous pathology, we retrospectively examined kidneys from a total of 505 control Cynomolgus monkeys ( Macaca fascicularis; 264 male and 241 females) aged 2 to 6 years, from toxicity studies. Kidney weights, urinalysis, and kidney-related clinical biochemistry parameters were also evaluated. Although the functional anatomy of the monkey kidney is relatively similar to that of other laboratory animals and humans, a few differences and species-specific peculiarities exist. Unlike humans, the macaque kidney is unipapillate, with a relatively underdeveloped papilla, scarce long loops of Henle, and a near-equivalent cortical to medullary ratio. The most common spontaneous microscopic findings were interstitial infiltrates or interstitial nephritis and other tubular lesions, but several forms of glomerulopathy that may be interpreted as drug-induced were occasionally observed. Common incidental findings of little pathological significance included: papillary mineralization, epithelial pigment, multinucleate cells, cuboidal metaplasia of the Bowman’s capsule, and urothelial inclusions. Kidney weights, and some clinical chemistry parameters, showed age- and sex-related variations. Taken together, these data will aid the toxicologic pathologist to better evaluate the nonhuman primate kidney and assess the species’ suitability as a model for identifying and characterizing drug-induced injury.

The Analysis of Renal Anatomy and Histological Changes of Green Iguana (Iguana Iguana) After Feeding With Red Spinach (Amaranthus tricolor L.)

Background and Objective: Iguana breeders usually used red spinach as a feed for iguanas. However, several studies have indicated that red spinach contains oxalate and purine which are harmful if consumed at a certain level because they can interfere with kidney function. This study aimed to investigate the change of anatomy and histology of green iguana (Iguana iguana) kidney after feeding with red spinach. Materials and methods: Twelve iguanas were used in this study and were divided into four groups in accordance to the dose level of red spinach (100%, 75%, 50% and 25%, namely group I to IV, respectively). The red spinach was given for 30 days through the nasogastric intubation. The effect of red spinach administration was observed through the anatomy and histological changes. The results were statistically analyzed with One Way ANOVA with p<0.05 was considered significant, and Post Hoc Test. The histopathology change of the kidney was analyzed descriptively. Results: The administration of red spinach in iguanas caused some anatomy changes of the kidney; such as the enlargement of iguana’s kidney. The histological findings included the enlargement of the glomerulus, capsular space constriction, hydropic degeneration, tubular dilation, necrosis, and formation of connective tissue (fibrosis), uric acid crystal sediment (gout), oxalate crystal, and lymphocyte infiltration. Among four different dose levels of red spinach, 100% of red spinach caused the highest damage to the iguana’s kidney. The significant change grew as the increasing dose of red spinach that was given to the green iguanas’ bodies. Conclusion: Red spinach caused changes in anatomy structure as well as kidney histology of green iguanas. Severe damages occurred in the treatment group III, moderate damage occurredin the treatment group II, and light damage occurred in the treatment group I. Keywords: Green iguana, Red spinach, Kidney, Anatomy Change, Histology Change

Kidney anatomy, histology and histometric traits associated to renosomatic index in Gymnotus inaequilabiatus (Gymnotiformes: Gymnotidae)

ABSTRACT The Gymnotus inaequilabiatus is a Neotropical fish widely distributed in marginal areas of bays. The aim of this study was to describe the main histological and histopathological traits in the head and exocrine kidney. Here, histometric and structural density techniques were associated with renosomatic index (RSI). The kidney was processed for light microscopy. Lipofuscin and hemosiderin content were visually estimated in the melonomacrophages centers (MMCs). All the biometric body variables were correlated with RSI, especially the kidney weight and gross lesions count. The general architecture of head and exocrine kidney was similar to that described for other teleost species. MMCs were prevalent in both portions and correlated with RSI in the head and exocrine kidney. Granulomatous structures were often observed in both portions; however, they were associated only in the exocrine kidney with RSI. Of all the structures hystometrically estimated, only proximal tubular diameter and thickness, and distal tubular thickness were correlated to renosomatic index. The RSI is an useful biometric variable that represent some physiological and morphological characteristics of kidney in G. inaequilabiatus. These findings may be used in future studies to evaluate the effects of environmental stressors on the renal adaptative physiological process.

Somatotypological features of topographic kidney anatomy of patients without any kidney and urinary tract diseases

The conducted analysis of modern literature shows that most of the establishednormative parameters of the placement of kidneys in healthy people have not beensufficiently studied, with researchers practically do not take into account the constitutionalfeatures of the organism. The purpose of the study was to determine the topographicanatomical position of the kidneys in the frontal, sagittal and horizontal planes on thebasis of MRI in patients of different somatotypes without any kidney and urinary tractdiseases. Complex examination of 65 patients of the first and second mature age ofdifferent somatotypes, which did not have kidney and urinary tract diseases, wasperformed. To determine the somatotype, we used the mathematical scheme forB.Heath and J.Carter (1990), with the definition of the endomorphic, mesomorphic andectomorphic components of the somatotype. The renal topography was conducted ona Philips Intera-1.5T magnetic resonance imaging (standard magnetic resonance protocolincluded scanning in sagittal, frontal, and axial projections to obtain T1 weighted imaging).The angles of inclination were measured in the frontal, sagital and horizontal planes tomeasure spatial position of the kidneys. The statistical analysis of the obtained resultswas carried out using the "STATISTICA 5.5" program, using parametric and non-parametricmethods for evaluating the obtained results. It was established that the angle ofinclination of the kidney on the right side in the frontal and sagittal planes was greater in1.23-1.41 times than in men and in women of representatives of all somatotypes. Theangle between the axis and the line drawn through the middle of the vertebral bodiesdid not statistically significantly change, depending on the somatotype, sex and on theside of the study in a horizontal plane. The angles of inclination of the kidney axis aredefined in three planes: the frontal, horizontal, and sagittal in the patients, with thekidney axis directed downwards outward and forward. Representatives of allsomatotypes differed statistically significantly the angles of inclination of the left axisfrom the right kidneys in the frontal and sagittal planes