Severe hypernatremia from a urea-induced diuresis due to body protein wasting in an insulin-resistant type 2 diabetic patient

CONTEXT

Hypernatremia is encountered after pituitary or hypothalamic surgery and typically is secondary to vasopressin deficiency resulting in increased free water clearance with inadequate water replacement.

OBJECTIVE

We report a type 2 diabetic patient with severe hypernatremia (Na⁺ = 161 mEq/L) after hypothalamic surgery. Unexpectedly, this was accompanied by persistent urinary hypertonicity and negative total but positive electrolyte free water clearance.

MAIN OUTCOME MEASURE

Measurement of urinary electrolytes and urea revealed that an osmotic diuresis induced by urea derived principally by breakdown of endogenous protein was causative. Body protein losses over 48 hours were estimated to exceed 2 kg of lean mass. High-dose glucocorticoid, insulin resistance, and a postsurgical catabolic stress likely contributed.

CONCLUSION

In surgically severely stressed individuals, proteolysis of endogenous protein can strongly impact body water metabolism and contribute to severe hypernatremia.

Renal support in acute kidney injury

Acute kidney injury requiring renal replacement therapy (RRT) is associated with an unacceptably high mortality rate. Despite the identification of the modality, timing and intensity of dialysis, membrane biocompatibility, hollow fiber and catheter properties as potential modifying factors, there is little convincing evidence for the superiority of one over the other. However, the available data suggest that the early initiation of RRT may be beneficial. A focused review of clinical trials and meta-analysis of clinical trials of RRT is provided.

Role in diuresis of a calcitonin receptor (GPRCAL1) expressed in a distal-proximal gradient in renal organs of the mosquito Aedes aegypti (L.)

Evolution of anthropophilic hematophagy in insects resulted in the coordination of various physiological processes for survival. In female mosquitoes, a large blood meal provides proteins for egg production and as a trade-off, rapid elimination of the excess water and solutes (Na(+), Cl(-)) is critical for maintaining homeostasis and removing excess weight to resume flight and avoid predation. This post-prandial excretion is achieved by the concerted action of multiple hormones. Diuresis and natriuresis elicited by the calcitonin-like diuretic hormone 31 (DH(31)) are believed to be mediated by a yet uncharacterized calcitonin receptor (GPRCAL) in the mosquito Malpighian tubules (MTs), the renal organs. To contribute knowledge on endocrinology of mosquito diuresis we cloned GPRCAL1 from MT cDNA. This receptor is the ortholog of the DH(31) receptor from Drosophila melanogaster that is expressed in principal cells of the fruit fly MT. Immunofluorescence similarly showed AaegGPRCAL1 is present in MT principal cells in A. aegypti, however, exhibiting an overall gradient-like pattern along the tubule novel for a GPCR in insects. Variegated, cell-specific receptor expression revealed a subpopulation of otherwise phenotypically similar principal cells. To investigate the receptor contribution to fluid elimination, RNAi was followed by urine measurement assays. In vitro, MTs from females that underwent AaegGPRcal1 knock-down exhibited up to 57% decrease in the rate of fluid secretion in response to DH(31). Live females treated with AaegGPRcal1 dsRNA exhibited 30% reduction in fluid excreted after a blood meal. The RNAi-induced phenotype demonstrates the critical contribution of this single secretin-like family B GPCR to fluid excretion in invertebrates and highlights its relevance for the blood feeding adaptation. Our results with the mosquito AaegGPRCAL1 imply that the regulatory function of calcitonin-like receptors for ion and fluid transport in renal organs arose early in evolution.

Gastric bypass surgery is followed by lowered blood pressure and increased diuresis - long term results from the Swedish Obese Subjects (SOS) study

Objective

To compare two bariatric surgical principles with regard to effects on blood pressure and salt intake.

Background

In most patients bariatric surgery induces a sustained weight loss and a reduced cardiovascular risk profile but the long-term effect on blood pressure is uncertain.

Methods

Cohort study with data from the prospective, controlled Swedish Obese Subjects (SOS) study involving 480 primary health care centres and 25 surgical departments in Sweden. Obese patients treated with non-surgical methods (Controls, n = 1636 and n = 1132 at 2 y and 10 y follow up, respectively) were compared to patients treated with gastric bypass (GBP, n = 245 and n = 277, respectively) or purely restrictive procedures (vertical banded gastroplasty or gastric banding; VBG/B, n = 1534 and n = 1064, respectively).

Results

At long-term follow-up (median 10 y) GBP was associated with lowered systolic (mean: −5.1 mm Hg) and diastolic pressure (−5.6 mmHg) differing significantly from both VBG/B (−1.5 and −2.1 mmHg, respectively; p<0.001) and Controls (+1.2 and −3.8 mmHg, respectively; p<0.01). Diurnal urinary output was +100 ml (P<0.05) and +170 ml (P<0.001) higher in GBP subjects than in weight-loss matched VBG/B subjects at the 2 y and 10 y follow-ups, respectively. Urinary output was linearly associated with blood pressure only after GBP and these patients consumed approximately 1 g salt per day more at the follow-ups than did VBG/B (P<0.01).

Conclusions

The purely restrictive techniques VBG/B exerted a transient blood pressure lowering effect, whereas gastric bypass was associated with a sustained blood pressure reduction and an increased diuresis. The daily salt consumption was higher after gastric bypass than after restrictive bariatric surgery.

Early alteration of urinary exosomal aquaporin 1 and transforming growth factor β1 after release of unilateral pelviureteral junction obstruction

BACKGROUND/PURPOSE

Down-regulation of aquaporin 1 (AQP1) and up-regulation of transforming growth factor β(1) (TGF-β(1)) in the renal parenchyma have been demonstrated in children who underwent pyeloplasty for pelviureteral junction obstruction. However, no information about urinary exosomal AQP1 and TGF-β(1) during postobstructive polyuria in children with congenital unilateral hydronephrosis is available. The aim of the present study is to evaluate the urine concentration of exosomal AQP1 and TGF-β(1) on the first and the second day after surgery in children who underwent pyeloplasty.

METHODS

Twenty-two patients (age, 36.2 ± 17.1 months) with unilateral pelviureteral junction obstruction were examined in the study. For the first 2 days after the operation, the urine was collected separately from pyelostomy draining only from the postobstructed kidney and from the bladder catheter draining mostly from the contralateral kidney, which was used as an internal control. Urinary output, urinary osmolality, sodium, β(2)-microglobulin (β(2)-MG), and creatinine, as well as urinary exosomal AQP1 and TGF-β(1) excretion, were tested in each sample.

RESULTS

After pyeloplasty, a significantly decreased urinary excretion of exosomal AQP1 (≈ 64%) was found in the postobstructed kidney. The patients developed polyuria (807 ± 216 mL/24 h vs 484 ± 144 mL/24 h at day 1, 1021 ± 348 mL/24 h vs 603 ± 228 mL/24 h at day 2; P < .01) and reduced urine osmolality (115 ± 44 mOsm/kg vs 282 ± 61 mOsm/kg at day 1, 139 ± 39 vs 303 ± 46 mOsm/kg at day 2; P < .01) that persisted for 48 hours. In parallel, urinary TGF-β(1) and β(2)-MG (normalized for creatinine) from the postobstructed kidney were significantly higher compared with the contralateral kidney. The urine output and urinary sodium concentration from the postobstructed kidney elevated significantly on the second day after the release of obstruction compared with those on the first day. The contralateral kidney also showed same trends.

CONCLUSIONS

The down-regulation of urinary exosomal AQP1 in the postobstructed kidney may account for the polyuria, hypotonic urine, and elevated urinary β(2)-MG. The urinary TGF-β(1) level locally increased in the postobstructed kidney may be involved in renal AQP1 down-regulation.

EFFECT OF l-TRYPTOPHAN ON DIURESIS AND 5-HYDROXYINDOLEACETIC ACID EXCRETION IN THE RAT

Oral administration of L-tryptophan to rats produced two main biochemical and pharmacological effects: a marked increase in urinary 5-hydroxyindoleacetic acid excretion, and a significant reduction in the urine flow after a water load. Urinary 5-hydroxyindoleacetic acid excretion reached its maximum 2 to 6 hr after the administration of tryptophan, and it increased with the dose of the amino acid. Antidiuresis was seen after the administration of L-tryptophan, 200 mg/kg, or more. The effect appeared promptly and it was roughly proportional to the dose of the amino acid administered. Both antidiuretic effect and increase in urinary 5-hydroxyindoleacetic acid excretion were more intense after oral than after parenteral administration of L-tryptophan. D-Tryptophan, in oral doses up to 1,000 mg/kg, produced neither an increase in urinary 5-hydroxyindoleacetic acid nor a reduction of diuresis. Available evidence suggests that reduction of urine flow is a consequence of biosynthesis and release of 5-hydroxytryptamine by the gastrointestinal mucosa. Tryptamine produced by direct decarboxylation of L-tryptophan does not seem to play any important role.

[Effects of herbs capable of activating blood circulation or inducing diuresis on the expressions of tumor necrosis factor-alpha, nuclear factor-kappaB, and aquaporin-4 in rats with intracerebral hemorrhage]

OBJECTIVE

To investigate the effects of herbs capable of activating blood circulation or inducing diuresis on the expressions of tumor necrosis factor-alpha (TNF-alpha), nuclear factor-kappaB (NF-kappaB), and aquaporin-4 (AQP-4) in rats with intracerebral hemorrhage (ICH), and to study their possible mechanisms.

METHODS

The ICH rat model was established by injecting autologous arterial blood into the right caudate nucleus. The 168 male rats were randomly divided into four groups, the sham-operative group, the model group, the blood activating group, and the diuresis inducing group, 42 in each group. Chinese compound decoction (consisting of 0.2 g rhubarb, 0.02 g leech, and 0.3 g notoginseng in each milliliter decoction) was given to rats in the blood activating group by gastrogavage at the dose of 10 mL/kg, once daily. Chinese compound decoction (consisting of 0.2 g poria, 0.2 g water plantain tuber, and 0.2 g acori graninei in each milliliter decoction) was given to rats in the diuresis inducing group by gastrogavage at the dose of 10 mL/kg, once daily. 4.0 mL/kg normal saline was given to rats in the model group and the sham-operative group by gastrogavage, once daily. A series of brain samples were obtained on the 1st, 3rd, and 5th day, respectively. The mRNA and protein expressions of TNFalpha, NF-kappaB p65, and AQP-4 were determined by immunohistochemical staining and Real-time fluorescent quantitative PCR respectively.

RESULTS

After ICH, TNF-alpha, NF-KB, and AQP-4 protein positive cells in the brain tissue and their protein and mRNA expressions significantly increased in rats of the model group at each time point when compared with the sham-operative group (P < 0.01, P < 0.05). The gene and protein expressions of TNF-alpha and AQP-4 significantly decreased in the blood activating group and the diuresis inducing group at each time point when compared with the model group (PP < 0.05). The expression of NF-kappaB p65 in the blood activating group obviously decreased when compared with the model group (P < 0.05), but there was no statistical difference in the NF-KB expression when compared with the diuresis inducing group (P > 0.05). Compared with the model group, the water content of the brain tissue decreased to some degree in the blood activating group and the diuresis inducing group at each time point. There was statistical difference between the blood activating group and the diuresis inducing group (P < 0.05).

CONCLUSIONS

Chinese herbs capable of activating blood circulation or inducing diuresis could inhibit the release of TNF-alpha, down-regulate the expression of AQP-4, and alleviate the brain edema around hematoma. But the action strength and the effect links were different.

Guidance document for structured reporting of diuresis renography

This Guidance Document for structured reporting of diuresis renography in adults was developed by the International Scientific Committee of Radionuclides in Nephro-urology (ISCORN; http://www.iscorn.org). ISCORN chose diuresis renography for its first structured report Guidance Document because suspected obstruction is the most common reason for referral, most radionuclide renal studies are conducted at institutions that perform fewer than 3 studies per week, and a large percentage of studies are interpreted by physicians with limited training in nuclear medicine. Ten panelists were asked to categorize specific reporting elements as essential, recommended, optional (without sufficient data to support a higher ranking), and unnecessary (does not contribute to scan interpretation or quality assurance). The final document was developed through an iterative series of comments and questionnaires with a majority vote required to place an element in a specific category. The Guidance Document recommends a reporting structure organized into indications, clinical history, study procedure, findings and impression and specifies the elements considered essential or recommended in each category. The Guidance Document is not intended to be restrictive but, rather, to provide a basic structure and rationale so that the diuresis renography report will: (1) communicate the results to the referring physician in a clear and concise manner designed to optimize patient care; (2) contain the essential elements required to evaluate and interpret the study; (3) clearly document the technical components of the study necessary for accountability, quality assurance and reimbursement; and (4) encourage clinical research by facilitating better comparison and extrapolation of results between institutions.

The effect of peritoneal dialysis method on residual renal function in children

We set out to assess the effect of continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) on residual renal function (RRF) in children with end-stage renal disease (ESRD). In 101 children (age: 8.84 +/- 5.25 years; 44 on CAPD, 57 on APD) over 36 months, we evaluated RRF [as daily diuresis (DD) in mL/kg/24 h and mL/m2/24 h], glomerular filtration rate [GFR (in mL/min/1.73 m2)], ESRD cause, presence of arterial hypertension (HTN), biochemical parameters, peritoneal equilibration test (PET), adequacy [as total weekly Kt/V (twKt/V) and creatinine clearance (twCCr)], and infectious complications of PD. Initially, the CAPD and APD groups did not differ significantly in DD, but mean GFR was significantly higher in the APD group (p < 0.05). In the CAPD group, the volume of high osmolarity PD fluid was significantly lower (p < 0.05), and the rates of peritonitis and exit-site infection and of aminoglycoside use were higher (p < 0.001, p < 0.05, and p < 0.005 respectively). Over 36 months, the mean twKt/V and twCCr were within norms in both groups, but were higher in APD, significantly so (p < 0.05) for twKt/V at 24 and 36 months and for twCCr initially. In both groups, RRF decreased systematically, with a significantly lower (p < 0.05) rate of DD (mL/m2/24 h) and GFR decline in the first year in CAPD, but without a difference in the next 2 years. The longest RRF preservation was in children with tubulointerstitial nephropathies, particularly hypoplasia and dysplasia (p < 0.05). Children with hemolytic uremic syndrome (HUS) and hereditary nephropathy were at the highest anuria risk. Compared with the 22 children (7 CAPD, 15 APD) who became anuric, the 20 children (10 CAPD, 10 APD) with RRF preserved for 36 months had a higher DD and GFR before dialysis onset; higher hemoglobin and albumin; and lower HTN prevalence, cholesterol, triglycerides, and proteinuria (p < 0.05). Risk of anuria during 36 months did not differ significantly between the CAPD and APD groups. In children on CAPD or APD, risk factors for RRF loss include HUS, hereditary nephropathy, low diuresis and GFR before dialysis onset, HTN, anemia, hypoalbuminemia, hyperlipidemia, and proteinuria. Compared with children on APD, those on CAPD show better preservation of RRF during year 1, although the risk of anuria seems to be the same for both methods. In children with risk factors for rapid diuresis loss, CAPD might be considered the preferred initial dialysis method.

Understanding hypernatremia

Understanding hypernatremia is at times difficult for many clinicians. However, hypernatremia can often be deciphered easily with some basic understanding of water and sodium balance. Here, the basic pathophysiological abnormalities underlying the development of sodium disorders are reviewed, and case examples are given. Hypernatremia often arises in the hospital, especially in the intensive care units due to the combination of (1) not being able to drink water; (2) inability to concentrate the urine (most often from having kidney failure); (3) osmotic diuresis from having high serum urea concentrations, and (4) large urine or stool outputs.

Nephrolithiasis in medullary sponge kidney: evaluation of clinical and metabolic features

OBJECTIVE

Medullary sponge kidney (MSK) is a disorder characterized by tubular dilation of renal collecting ducts and cystic dilation of medullary pyramids that has been associated with stone disease. The significance of nephrolithiasis and the mechanisms by which it occurs are incompletely understood. We describe clinical and metabolic features of nephrolithiasis in a cohort of patients with MSK.

METHODS

Records were reviewed of 56 patients, all with radiographic diagnosis of medullary sponge kidney and data collected pertaining to presentation, stone events and recurrences, stone composition, and metabolic profile to perform a descriptive study with median 3.7 years follow-up.

RESULTS

Nephrolithiasis was confirmed radiographically in 39/56 patients (69.6%). No patient without evidence of nephrolithiasis developed a stone event, whereas 13/39 (33%) of those with nephrolithiasis developed a recurrent stone event. Stones were composed of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate apatite, and uric acid. Metabolic profile was obtained for 26 of 39 (67%) stone-forming patients demonstrating abnormalities in 22/26 (84.6%). These included hypercalciuria, 58% (15/26); low urine volume, 35% (9/26); hyperuricosuria, 27% (7/26); hypocitraturia, 19% (5/26); elevated urine sodium, 15% (4/26); and hyperoxaluria, 12% (3/26).

CONCLUSION

Many patients with MSK have no evidence of nephrolithiasis. Among those who do, recurrence is common, and metabolic profile and composition are varied as in the general stone-forming population.

Modulation of pressure-natriuresis by renal medullary reactive oxygen species and nitric oxide

The renal pressure-natriuresis mechanism is the dominant controller of body fluid balance and long-term arterial pressure. In recent years, it has become clear that the balance of reactive oxygen and nitrogen species within the renal medullary region is a key determinant of the set point of the renal pressure-natriuresis curve. The development of renal medullary oxidative stress causes dysfunction of the pressure-natriuresis mechanism and contributes to the development of hypertension in numerous disease models. The purpose of this review is to point out the known mechanisms within the renal medulla through which reactive oxygen and nitrogen species modulate the pressure-natriuresis response and to update the reader on recent advances in this field.

Confounders in the assessment of the renal effects associated with low-level urinary cadmium: an analysis in industrial workers

BACKGROUND

Associations of proteinuria with low-level urinary cadmium (Cd) are currently interpreted as the sign of renal dysfunction induced by Cd. Few studies have considered the possibility that these associations might be non causal and arise from confounding by factors influencing the renal excretion of Cd and proteins.

METHODS

We examined 184 healthy male workers (mean age, 39.5 years) from a zinc smelter (n = 132) or a blanket factory (n = 52). We measured the concentrations of Cd in blood (B-Cd) and the urinary excretion of Cd (U-Cd), retinol-binding protein (RBP), protein HC and albumin. Associations between biomarkers of metal exposure and urinary proteins were assessed by simple and multiple regression analyses.

RESULTS

The medians (interquartile range) of B-Cd (μg/l) and U-Cd (μg/g creatinine) were 0.80 (0.45-1.16) and 0.70 (0.40-1.3) in smelter workers and 0.66 (0.47-0.87) and 0.55 (0.40-0.90) in blanket factory workers, respectively. Occupation had no influence on these values, which varied mainly with smoking habits. In univariate analysis, concentrations of RBP and protein HC in urine were significantly correlated with both U-Cd and B-Cd but these associations were substantially weakened by the adjustment for current smoking and the residual influence of diuresis after correction for urinary creatinine. Albumin in urine did not correlate with B-Cd but was consistently associated with U-Cd through a relationship, which was unaffected by smoking or diuresis. Further analyses showed that RBP and albumin in urine mutually distort their associations with U-Cd and that the relationship between RBP and Cd in urine was almost the replicate of that linking RBP to albumin

CONCLUSIONS

Associations between proteinuria and low-level urinary Cd should be interpreted with caution as they appear to be largely driven by diuresis, current smoking and probably also the co-excretion of Cd with plasma proteins.

Blockade of 5-Hydroxytryptamine Antidiuresis in Rats by 2-Bromlysergic Acid Diethylamide Tartrate and 1-Methyl-Lysergic Acid Butanolamide

The effects of two lysergic acid derivatives, 2-bromlysergic acid diethylamide ‘BOL 148’ and 1-methyl-lysergic acid butanolamide ‘UML 491’ on the antidiuresis induced by 5-hydroxytryptamine ‘5-HT’ has been studied in rats given a dose of 1 mg./kg. 5-HT subcutaneously. BOL 148, 5 mg./kg., and UML 491, 2·5 mg./kg., counteracted the induced antidiuresis. By contrast, the antidiuretic effect of posterior pituitary extract was not blocked or diminished by BOL 148 or by UML 491. BOL 148 and UML 491 alone did not have a diuretic or antidiuretic action.

Managing hyponatremia in patients with syndrome of inappropriate antidiuretic hormone secretion

Disorders of sodium [Na+] and water metabolism are commonly encountered in the hospital setting due to the wide range of disease states that can disrupt the balanced control of water and solute intake and output. In particular, the prompt identification and appropriate management of abnormally low serum [Na+] is critical if we are to reduce the increased morbidity and mortality that accompany hyponatremia in hospitalized patients. Use of an algorithm that is based primarily on the symptomatology of hyponatremic patients, rather than the serum [Na+] or the chronicity of the hyponatremia, will help to choose the correct initial therapy in hospitalized hyponatremic patients. However, careful monitoring of serum [Na+] responses is required in all cases to adjust therapy appropriately in response to changing clinical conditions. Although this approach will enable efficacious and safe treatment of hyponatremic patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) at the present time, evolving knowledge of the consequences of chronic hyponatremia will likely alter treatment indications and guidelines in the future.

Cardiac morphology and function in patients with and without residual diuresis on hemodialysis

In patients with chronic renal failure on hemodialysis, left ventricular hypertrophy is related to the increase in total peripheral vascular resistance and volume overload. The presence of residual diuresis enables greater control of the volemia of these. We evaluated the morpho-functional changes of the left ventricle in patients with chronic kidney disease on hemodyalisis treatment with and without residual diuresis. A total of 31 non diabetic patients were studied and they were divided into two groups: with residual diuresis (RD+) (n = 17) and without residual diuresis (RD-) (n = 14). In both groups, RD+ vs. RD-, using data from a Doppler echocardiogram differences were found, respectively, in the cardiac index (3.9 ± 0.2 vs. 3.0 ± 0.2 L/min/m²; p = 0.0056), systolic index (54 ± 2.9 vs. 45 ± 3.3 mL/b/m²; p = 0.04), end diastolic volume (141 ± 6.7 vs. 112 ± 7.6 mL; p = 0.008), end diastolic diameter (52 ± 0.7 vs. 48 ± 1.1 mm; p = 0.0072) and total peripheral resistance index (1121 ± 56 vs. 1529 ± 111 dyne.sec.cm-5; p = 0.001). RD+ had lower relative wall thickness than RD- (0.38 ± 0.01 vs. 0.45 ± 0.01; p = 0.0008). The ejection fraction and the left ventricular mass index were similar in both groups. The urinary 24-hour volume correlated with the relative wall thickness (r = -0.42; p = 0.0186) and with peripheral resistance index (r = -0.48; p = 0.0059). In conclusion, there were distinct ventricular geometric patterns and different functional performances between RD+ and RD- groups. The presence of residual diuresis can be responsible by these modifications in systolic function.

Enteric neurons and systemic signals couple nutritional and reproductive status with intestinal homeostasis

The gastrointestinal tract is emerging as a key regulator of appetite and metabolism, but daunting neuroanatomical complexity has hampered identification of the relevant signals. Invertebrate models could provide a simple and genetically amenable alternative, but their autonomic nervous system and its visceral functions remain largely unexplored. Here we develop a quantitative method based on defecation behavior to uncover a central role for the Drosophila intestine in the regulation of nutrient intake, fluid, and ion balance. We then identify a key homeostatic role for autonomic neurons and hormones, including a brain-gut circuit of insulin-producing neurons modulating appetite, a vasopressin-like system essential for fluid homeostasis, and enteric neurons mediating sex peptide-induced changes in intestinal physiology. These conserved mechanisms of visceral control, analogous to those found in the enteric nervous system and hypothalamic/pituitary axis, enable the study of autonomic control in a model organism that has proved instrumental in understanding sensory and motor systems.

[Effects of water drinking regimens on crystallization intensity in experimental nephrolithiasis]

We studied effects of water regimens on crystallization efficacy in experimental nephrolithiasis on 3 groups of Wistar male rats with initial experimental nephrolithiasis (ethylene glycol model). The animals were on free, limited and supernormal liquid intake regimen. For 3 weeks each 3-4 days we estimated 24-h diuresis, urine concentration of calcium, phosphate and oxalate ions. After 3 weeks we made a morphological examination of the kidneys. We found that limited drinking leads to an increase in urinary concentrations of oxalate- and phosphate ions which stimulate enhanced formation of calcium-containing concrements. More water intake considerably reduces oxalate and phosphate concentrations in the urine resulting in reduction of the number and size of calcium deposits in renal tissue. Thus, low liquid intake leads to intensification of urine oversaturation causing formation of renal concrements. Much liquid intake weakens oversaturation and reduces the number and size of calcium deposits in the kidneys.

Assessment of intestinal permeability using sugar probes: influence of urinary volume

BACKGROUND

As the accuracy of the "Sugar Test" is currently debated, this study was conducted to focus on how urine volumes may impact the test results.

METHODS

Fifty-five subjects, 23 healthy and 32 with Irritable Bowel Syndrome (IBS), were enrolled. Lactulose and D-mannitol dissolved in water were administered to all the participating subjects; the urine excreted was collected and the total urine volume was measured. The urine samples were analyzed by High Performance Liquid Chromatography (HPLC). The results were expressed as percentage of urine recovery of lactulose and D-mannitol and lactulose/D-mannitol ratio (LMR).

RESULTS

All subjects were divided into two groups: subjects with urine volume < 500 mL and subjects with urine volume > or = 500 mL. Urine analysis showed that the mean LMR was significantly lower in subjects with urine volume > or = 500 mL than in subjects with urine volume < 500 mL (0.02 +/- 0.02 vs 0.04 +/- 0.04; p < 0.05). A significant increase in D-mannitol recovery was found to be associated with greater urine volumes (p < 0.001).

CONCLUSIONS

The urine volume may influence urinary excretion of sugar probes. Intake of liquids should therefore be carefully monitored before and during the test and the volume of urine produced over the period of collection should be precisely measured.

Aquaporin-2 urinary excretion in preterm infants: relationship to diuresis and vasopressin

AIMS

Few investigations have explored the urinary aquaporin-2 (u-AQP2) excretion pattern after birth in preterm infants with conflicting results regarding the correlation between u-AQP2, urinary osmolality and vasopressin. The aims of this study were to evaluate u-AQP2 excretion during the first week of life in preterm infants, to correlate u-AQP2 with other markers of renal function and to investigate the relationship between u-AQP2, urinary tonicity and arginine-vasopressin in the immature kidney.

METHODS

In infants born less than 33 weeks daily diuresis, u-AQP2, urinary arginine-vasopressin, urine and plasma tonicity, creatinine and electrolytes were measured through the first 7 days of life.

RESULTS

Fifty-five infants were evaluated. u-AQP2 excretion showed the following profile: the highest u-AQP2 levels were found on day 2 and values remained significantly higher until day 5 with respect to day 1. On day 6, u-AQP2 levels significantly decreased to values closer to those found on day 1. u-AQP2 excretion was not associated with arginine-vasopressin while significant, but weak association was found with urinary tonicity (r = -0.20; -0.32 < r < -0.11; P < 0.05). u-AQP2 excretion and creatinine clearance were significantly associated during the study period (r = 0.19; 0.08 < r < 0.29; P < 0.05). There was a strong association between totally u-AQP2 excretion and diuresis over the week (r = 0.72; 0.66 < r < 0.76; P < 0.0001).

CONCLUSION

Significant variations occur in AQP2 expression levels during the first week of life in preterm infants. AQP2 does not seem to contribute to the urinary concentration ability after birth. Further investigations are required to elucidate the mechanisms underlying the strong association between diuresis and u-AQP2 excretion in early postnatal life.

Epidemiology of acute kidney injury

Different definitions for acute kidney injury (AKI) once posed an important impediment to research. The RIFLE consensus classification was the first universally accepted definition for AKI, and has facilitated a much better understanding of the epidemiology of this condition. The RIFLE classification was adapted by a broad platform of world societies, the Acute Kidney Injury Network group, as the preferred AKI diagnostic and staging system. RIFLE defines three increasing severity stages of AKI. One- to two-thirds of intensive care unit (ICU) patients develop AKI according to these criteria which is associated with worse outcomes such as increased length of ICU stay, costs, and mortality. Over the last decade the incidence of AKI has increased, probably as a consequence that baseline characteristics of ICU patients have changed. Another factor that may explain this is that more patients are treated in clinical settings that are associated with high risk for development of AKI. In addition, there may be genetically predetermined risk profiles for development of AKI such homozygotes for the low activity form of the COMT gene. Mortality of AKI patients has decreased over the last few decades, especially when underlying severity of illness is considered. An important consequence of this is the increasing number of surviving AKI patients who develop chronic kidney disease and end-stage kidney disease. In the specific setting of cardiac surgery, AKI occurs in 19-45% of patients. Renal replacement therapy is necessary in approximately 2% of this cohort. AKI that occurs within a 7-day period after cardiac surgery is related to perioperative risk factors, such as preexisting chronic kidney disease, acute ischemia, aorta cross-clamping, or use of cardiopulmonary bypass. AKI that occurs after the first week is mostly a consequence of sepsis or heart failure.

[Oxalic acid--important uremic toxin]

INTRODUCTION

Oxalic acid is thought to be a significant uremic toxin that participates in the pathogenesis of uremic syndrome. AIM OF THE STUDY was to summarise results which we obtained during the study ofoxalic acid in biological fluids (plasma, saliva, urine and dialysate) in patients suffering from chronic kidney diseases (CKD), stage 3-5 and after renal transplantation.

PATIENTS AND METHODS

In the retrospective study were investigated 28 healthy subjects, 112 CKD stage 1-4 patients, 39 haemodialysis patients and 27 CAPD patients. Besides 21 patients were investigated after renal transplantation. We used the following therapeutic methods: maximal water diuresis, diet with low (2g/day) and high (15g/day) sodium chloride intake, administration intravenous furosemide (20mg) and renal replacement therapy [CAPD, haemodialysis (HD), haemofiltration (HF) and postdilution haemodiafiltration (HDF)] and renal transplantation. Oxalic acid was determined by spectrophotometric method using oxalate oxidase which is free from vitamin C interference. Vitamin C was determined by spectrophotometric method.

RESULTS

In CKD patients and those after renal transplantation direct relationships between plasma oxalic acid and serum creatinine were found (r = 0.904 and 0.943, respectively, P < 0.001). Despite of high plasma oxalic acid in uremic patients (23.1 +/- 10 micromol/l), there was no significant difference in salivary oxalic acid between control subjects (126.5 +/- 18 micromol/l) and CKD stage 3-4 patients (133.9 +/- 23.7 micromol/I). The urinary excretion of oxalic acid during maximal water diuresis in healthy subjects (n = 15) (from 37.5 +/- 17.4 to 110.2 +/- 49.3 micromol/4 hours) and after intravenous furosemide (CKD stage 3-4, n = 15) (from 34.5 +/- 5.5 to 66.7 +/- 8.1 micromol/3 hours) increased significantly, but was not affected by high intake of NaCI in diet (CKD stage 3-4, n = 12). One tablet of Sorbifer Durules containing 100 mg Fe2+ and 60 mg vitamin C did not lead to further increase of uremic hyperoxalemia in haemodialysis patients. Four-hour HD, H F and HDF led to the significant decrease of plasma oxalic acid, but the most significant decrease was observed during HDF (63.3%).

CONCLUSION

The results of this study indicate, that renal replacement therapy is not effective for permanent reduction of elevated plasma levels of oxalic acid--important uremic toxin.

[Anesthetic considerations in laparoscopy for removal of a kidney from a live donor]

Kidney transplantation is the main therapeutic alternative for patients with end-stage renal failure. However, the main constraint at present is the lack of available organs. Removal of a kidney from a live donor is a better option than conventional transplantation of a cadaver-donated organ. Among the advantages are a shorter waiting time for the organ recipient and greater assurance of graft quality and survival. The postoperative conditions made possible by laparoscopic surgery have encouraged the donation of tissues by live donors. Anesthetic treatment for patients undergoing laparoscopic surgery must be based on an understanding of the pathophysiologic changes that occur in this type of procedure so that complications can be prevented. This review provides an update of progress in laparoscopic surgery and the repercussions of anesthetic management, particularly with respect to anesthesia for kidney donors.

[Hyponatremia in heart failure: physiopathology and pharmacological approach]

Hyponatremia is a well-known adverse prognostic factor in patients with chronic heart failure. The mechanisms linking hyponatremia with poor outcomes in these patients are not well understood and may be related to the presence of the abnormal management of water and neurohormonal activation seen in patients with chronic heart failure, which in turn are associated with a worse prognosis. Possibly, free-water retention exceeds the degree of sodium retention in chronic heart failure, which could partially explain the hyponatremia found in these patients. There are several therapeutic strategies for the management of hyponatremia in patients with chronic heart failure, including fluid restriction, high-dose diuretic administration and infusion of hypertonic saline, but none has been proven to be very effective. Recently, vasopressin antagonism through vasopressin receptor antagonists has opened up a new way of treating hyponatremia in these patients by enhancing aquaresis. Several agents are available but their possible impact on morbidity and mortality in patients with hyponatremia and chronic heart failure requires elucidation.

Mineral water administration may increase kidney elimination of urea, creatinine and folic acid in a concentration-dependent fashion

BACKGROUND

In a previous experimental study we showed that the administration of a large water load in a short time increases the urinary flow and the transport capacity in the excretory tract of the rabbit ureter. In human subjects drinking a water load of 25 ml/kg(BW) in 30 minutes, diuresis, creatinine and urea clearance increase more than in those drinking the same load in 24 hours.

PURPOSE

The aim of the present study was to investigate possible correlations between percent reduction and baseline values of serum urea, creatinine, folic acid, and magnesium in humans.

METHODS AND RESULTS

20 volunteers were divided in two groups. Subjects in group 1 received a water load of 25 ml/kg(BW) in 24 hours followed by the same load in 30 minutes. Subjects in group 2 received the same water load but in inverse order. Before and after each water administration, the following variables were measured and compared: diuresis, serum urea, creatinine, folic acid and magnesium concentration, and urea and creatinine clearance.

RESULTS

Serum urea and folic acid concentration decreased up to 40% after administration of the water load in 24 hours. Serum creatinine concentration decreased up to 20% after administration of the water load in 30 minutes. The concentration drop of these metabolites increased with increasing baseline metabolite concentrations.

Acute renal failure resulting from rhabdomyolysis following a seizure

A 30-year-old Indian man presented with progressive renal impairment following a seizure. The complaint of troublesome back pain led to the suspicion of rhabdomyolysis being the cause of acute renal failure. The diagnosis of rhabdomyolysis was supported by a markedly elevated serum creatinine phosphokinase level. Magnetic resonance imaging revealed a right paraspinal muscle tear. The patient underwent haemodialysis and subsequently had a rapid and complete recovery.

[Case of ischemic heart disease resulting from persistent diuresis after giant ovarian tumor resection]

A patient with a giant ovarian tumor weighing about 7 kg was successfully removed by operation. However, her ECG demonstrated ischemic changes after the operation. We report a case of ischemic heart disease due to persistent diuresis after giant ovarian tumor resection. A 75-year-old, 56.5 kg, 143.5 cm woman was admitted to our hospital for ovarian tumor resection. The preoperative ECG showed normal sinus rhythm and no ischemic changes. Both general anesthesia and epidural anesthesia were planed. An epidural catheter was inserted at T12-L1. Anesthesia was induced with propofol 100 mg, fentanyl 100 microg and vecuronium 8 mg under 100% oxygen inhalation. General anesthesia was maintained with sevoflurane while epidural anesthesia was achieved using 0.375% ropivacaine 6 ml. During the operation, blood pressure was 90-110/70-80 mmHg, with SaO2, 100% and heart rate, 70-80 beats x min(-1). The content of tumor was suctioned for 30 minutes. Surgery was successfully finished without any other incidence. After extubation, her ECG changed to atrial fibrillation from normal sinus rhythm and showed ST-T depression. And then her systolic blood pressure became 80 mmHg or below, but we found continued diuresis at about 10 ml x kg(-1) x hr(-1) for over 2 hr. The total of 7 unit vasopressin was intermittently given for vasoconstriction and antidiuresis. Her hemodynamic was immediately restored, and ECG turned to normal ST-T. The patient had uneventful postoperative recovery.

Case report: successful treatment of acute exertional paraspinal compartment syndrome with hyperbaric oxygen therapy

An NCAA football player developed an acute paraspinal compartment syndrome after a weight-lifting strain. The patient presented with myonecrosis (CK up to 77,400 U/L), and myoglobinuria. Treatment consisted of forced diuresis and six sessions in the hyperbaric oxygen chamber.

Renal functional & haemodynamic changes following acute unilateral renal denervation in Sprague Dawley rats

BACKGROUND & OBJECTIVES

Regulation of renal function and haemodynamics are under a direct control from the renal sympathetic nerves and renal denervation produces overt diuresis and natriuresis in several mammalian species. However, the inter-related series of changes in renal function and haemodynamics following acute renal denervation (ARD) is not fully understood. Thus, we aimed to investigate and relate the changes in renal function and haemodynamics following acute unilateral renal denervation in anaesthetized Sprague Dawley (SD) rats.

METHODS

Male SD rats were fasted overnight, anaesthetized with sodium pentobarbitone (60 mg/kg ip), denervated by application of phenol to the left renal artery and maintained on an intravenous (iv) infusion of isotonic saline for 2 h. Throughout this period, six urine and plasma samples were taken at 20-min intervals to study kidney function parameters. In a different set of experiments, renal nerve stimulation (RNS) was carried out to characterize the changes in renal vasoconstrictor responses following ARD.

RESULTS

Denervated animals showed significantly (P<0.05 vs. control innervated rats) higher urine flow rate (UFR), absolute sodium excretion (UNaV), fractional sodium excretion (FENa) and glomerular filtration rate (GFR). The renal vasoconstrictor responses to RNS were significantly (P<0.05) lower in denervated rats as compared to the innervated counterparts. However, no appreciable differences were seen in the mean arterial pressure (MAP), plasma sodium (PNa), basal renal blood flow (RBF) and basal renal vascular resistance (RVR) in both innervated and denervated SD rats.

INTERPRETATION & CONCLUSIONS

Natriuresis, diuresis, enhanced GFR and impaired vasoconstriction in response to RNS are typical and instant responses to ARD in SD rats. Renal sympathetic nerves serve more important role in salt and water conservation than in dynamic autoregulation of RBF under normal sympathetic tone; yet, their effects on renal haemodynamics become more evident in the presence of augmented renal sympathetic nerve activity (RSNA).

Cisplatin increases urinary sodium excretion in rats: gender-related differences

OBJECTIVE. There are well-documented reports of cisplatin-associated hyponatremia in the literature, but there are no data on gender-dependent differences. The aim of the present study was to define characteristics of 24-hour urinary sodium excretion in young adult Wistar rats of both genders and to evaluate the gender-related effect of cisplatin. MATERIALS AND METHODS. Twelve control Wistar rats (6 males and 6 females) and 12 cisplatin-treated Wistar rats (6 males and 6 females) after a single and repeated injection of cisplatin (once a day for 3 days) at a dose of 2.5 mg/kg body weight into the caudal vein were examined. The experiment was carried out by measuring 24-h urinary sodium, potassium, chloride, magnesium, creatinine excretion and pH in the urine of age-matched male and female rats. RESULTS. The 24-h urinary sodium excretion, sodium/chloride ratio, and diuresis showed no gender-related differences in control rats. After a single administration of 2.5 mg/kg cisplatin, 24-h urinary sodium excretion was not significantly higher in cisplatin-treated rats than in gender-matched controls. After repeated cisplatin administration, 24-h urinary sodium excretion was significantly higher in cisplatin-treated male rats as compared to matched controls (P<0.05). No such effect was found in cisplatin-treated female rats. CONCLUSION. The study data show that cisplatin enhances urinary sodium excretion in male but not in female rats. The mechanism of such a gender-related effect is not yet clear. Further investigations are necessary to elucidate the mechanism of this pharmacological effect of cisplatin.

Furosemide infusion prevents the requirement of renal replacement therapy after cardiac surgery

OBJECTIVE

Acute kidney injury (AKI) is a devastating complication following cardiac surgery and the ideal management is controversial. This prospective, randomized, open-label and double-blinded study analyzed the renoprotective effects of furosemide infusion and intermittent bolus therapy administered with dopamine infusion in cardiac surgical patients.

METHODS

Between August 1, 2007 and July 31, 2008, 100 adult patients undergoing elective coronary artery bypass surgery (CABG) surgery with normal renal function (creatinine <1.4 mg/dl) were enrolled in the study. The patients were randomized for the comparison of intermittent (Group 1, n=50, 1mg-3mg/kg) and continuous infusion of furosemide (Group 2, n=50, 10mg/ml). Continuous variables were expressed as mean+/- SD and compared by unpaired Student's t test or ANOVA for repeated measures. Statistical significance was assumed if p value was <0.05.

RESULTS

Renal replacement therapy (RRT) was used in 5% of patients (all in group 1, p=0.028). The 30-day mortality was 5%. Only 2 patients became hemodialysis dependent in group 1. Group 2 patients showed a continuous and higher urine output postoperatively than group 1 (p<0.001). Both groups had significant increase in peak postoperative serum creatinine values (p<0.001), however peak postoperative creatinine-clearance was significantly lower in group 1 (p<0.001).

CONCLUSION

Acute kidney injury necessitating RRT makes a small percentage of patients undergoing cardiac surgery and if RRT is not required the survival is excellent. Continuous infusion of furosemide seems to be effective in promoting diuresis and decreasing the need for RRT. However further multicenter studies with different doses of furosemide are required to confirm these results.

Effect of treatment with losartan on salt sensitivity and SGLT2 expression in hypertensive diabetic rats

Sodium-glucose cotransporters (SGLTs) in the kidney, may be involved in hypertension, diabetes and salt sensitivity. We evaluate the effect of losartan on blood pressure (BP) and SGLT2 expression in diabetic rats with high or normal salt diet. Losartan prevented an increase in BP and SGLT2 expression in diabetic rats.

Clinical and transperineal ultrasound findings in females with stress urinary incontinence versus normal controls

Study was aimed at comparing clinical and transperineal ultrasound findings of females with stress urinary incontinence and normal controls. Between 2004 and 2005, 40 women with stress urinary incontinence (mean age 47.5 years) diagnosed by history via ICIQ-SF (International consultation on Incontinence Questionnaire-Short Form) and 40 healthy female volunteers without any incontinence or LUTS (mean age 42.1 years) underwent transperineal ultrasonography for determination of posterior urethrovesical (beta) angle, bladder neck funneling and hypermobility of urethra. These findings were compared between patients and controls with regard to clinical data. Beta angle wider than 130 degrees, bladder neck funneling and hypermobility of urethra with transperineal ultrasonography were more common among cases than controls. LR (Likelihood Ratio) for urinary incontinence of these parameters was 2.5, 2.1 and 2, respectively. Perineal ultrasonography is highly associated with clinical findings. Hypermobility of urethra had highest sensitivity for diagnose of stress urinary incontinence but the specificity of bladder neck funneling in perineal sonography was higher.

Safety of low-dose cyclosporine therapy before transplantation in kidney allograft recipients

INTRODUCTION

Graft dysfunction immediately posttransplantation can vary from subtle slowing of the expected decrease in creatinine concentration to frank oliguria requiring dialysis therapy for days to weeks. Risk factors for slow and delayed graft function include prolonged preservation, older donor age, and high plasma renin activity in the recipient. Cyclosporine (CsA) nephrotoxicity is another cause of early kidney allograft dysfunction.

OBJECTIVE

To evaluate early kidney allograft function in patients who received low-dose CsA therapy for 48 hours before transplant surgery for comparison with that in recipients who received CsA therapy after improvement in allograft function.

PATIENTS AND METHODS

In a case-control comparative study, 66 kidney recipients were divided into 2 groups on the basis of time of initiation of CsA therapy. In group 1, patients received CsA, 100 mg twice a day, for 48 hours before surgery, and in group 2, patients received CsA therapy after surgery when allograft function had improved (serum creatinine concentration <or=3 mg/dL). Other immunosuppression medications were the same in both groups. Statistical analysis was performed to compare kidney allograft function in the first month posttransplantation.

RESULTS

In group 1 vs group 2, at day 1 posttransplantation, mean (SD) blood urea concentration was 73.72 (31.00) mg/dL vs 87.52 (29.82) mg/dL, serum creatinine concentration was 5.11 (1.83) mg/dL vs 6.42 (3.64) mg/dL, and urine volume in 24 hours was 11,052 (4290) mL vs 9629 (45.30) mL. At the end of the study, blood urea concentration was 49.61 (12.18) mg/dL vs 69.11 (33.76) mg/dL, serum creatinine concentration was 1.22 (0.28) mg/dL vs 1.47 (0.79) mg/dL, and urine volume in 24 hours was 3202 (986) mL vs 3095 (726) mL. No significant difference was noted between the 2 groups for age, sex, and immunosuppression medications.

CONCLUSION

Low-dose CsA therapy before transplant surgery preserves early allograft function without deleterious effects.

Extremely prolonged neuromuscular blockade after rocuronium: a case report

It is known that the duration of rocuronium action can be prolonged in elderly patients and that such action shows important interindividual variability. We report a case of prolonged neuromuscular block lasting 11 h, in a woman subjected to kidney transplantation. The possible causes of such prolonged action, inherent to the drug, or related to external factors, are commented.

Leptospiral Acute Renal Failure: Effects of Dopamine and Furosemide

From unpublished experience of clinicians in the rural tropics, the combination of furosemide and dopamine is beneficial in the management of mild acute renal failure in tropical disease. We studied two groups of patients with leptospirosis and mild acute renal failure whose serum creatinine ranged from 2.4 to 5 mg/dL and fractional excretion of sodium varied from 1.21 to 2.08%. Group 1, consisting of 9 patients with the serum creatinine ranging from 2.4 to 5 mg/dL, served as the control. They received only penicillin G sodium and supportive treatment. Group 2, consisting of 8 patients with the serum creatinine ranging from 2.8 to 5 mg/dL, received, in addition to penicillin, dopamine (renal dose) and furosemide along with fluid and electrolyte replacement. The control group ran the usual clinical course of acute renal failure, and 3 patients required dialysis. There was profuse diuresis, and the recovery of renal function was faster in group 2 patients. Dopamine and furosemide are therefore useful in mild acute renal failure in leptospirosis. It is felt that this combination could be beneficial in the management of mild acute ischemic renal failure due to a clean single insult.

Circadian rhythms of diuresis, proteinuria and natriuresis in children with chronic glomerular disease

The aim of our study was to examine diurnal variation in urine volume (UV) output, proteinuria (UPRT), urine creatinine (UCr) and urine sodium ion excretion (UNa) in children with chronic glomerulopathy. In 56 patients (20 boys/36 girls, aged 11.7 +/- 0.6 years) samples for UPRT, UCr and UNa were collected during the day and night, with continuous ambulatory blood pressure (BP) monitoring. On the basis of creatinine clearance (CrCl) the patients were divided into group I (n = 44, with CrCl 131 +/- 3.6 ml/min per 1.73 m(2) body surface area), or group II (n = 12, with CrCl 44.6 +/- 7.7 ml/min per 1.73 m(2) body surface area). Nocturnal polyuria was defined as night time UV >or= 35% of the 24 h UV. Age, gender, body mass index of the patients, 24 h UV, UCr and UNa were similar in both groups. However, arterial hypertension and nocturnal polyuria were widespread (P < 0.01) in group II. In addition, proteinuria was higher (P < 0. 05) in group II. The nocturnal decline in CrCl, UV, UPRT and UNa was significantly attenuated (P < 0.005) in patients in group II compared with those in group I. The night time mean arterial pressure (MAP), as well as the night/day ratios of MAP, UV, UPRT and UNa, showed negative associations with CrCl. Our findings strongly suggest that renal function diurnal variation and nocturnal MAP are related to decreased glomerular filtration rate at the time of examination.

Thallium intoxication treated with long-term hemodialysis, forced diuresis and Prussian blue

A 56-year-old woman, who ingested 2 g of thallium sulfate, was successfully treated with long-term hemodialysis for 200 hours during ten days, combined with forced diuresis and Prussian blue. The effect of the artificial kidney dialysis was determined by repeated analysis of the thallium concentration in the dialysis bath and in blood samples. During the first 120 hours of hemodialysis, 143 mg of thallium was eliminated via the artificial kidney and 110 mg via the urinary tract. The present case of acute thallium intoxication is the first in which long-term hemodialysis has been used in the acute phase together with forced diuresis and Prussian blue. The data obtained are compared to those obtained from cases treated with hemodialysis in the past. It is concluded that treatment with hemodialysis should be considered as an important supplement to treatment with forced diuresis and Prussian blue in cases of thallium intoxication.

Laboratory diagnosis of renal failure: urine conductivity and tubular function

AIM

Conductivity is a measure of a material's ability to conduct an electric current and it works thanks to movable charges. Conductivity in urine is directly proportional to ionic contents. The aim of this study was to evaluate the significance of urine conductivity by using the Sismex UF-100 analyser in correlations with other surrogate parameters of osmolality and renal diuresis, relative density, electrolytes and creatinine concentration.

METHODS

For this study 140 urine samples were submitted for diagnostic urinalysis to the Clinical Pathology laboratory. Samples were collected from 70 healthy subjects, 42 diabetics with poor metabolic control and significant glicosuria, 28 patients with monoclonal gammopathy of uncertain significance, with significant proteinuria. All the samples were assessed for conductivity (UF-100 Sysmex), relative density (refract meter Zeiss), sodium, potassium, chlorine, creatinine, urea, glucose, protein (Olympus AU-2700).

RESULTS

Urine conductivity appears to be related to ionic concentration but not to glucose and/or protein presence.

CONCLUSIONS

This study results suggest that conductivity determination should be useful in diabetic patients to study the tubular function minimising interferences due to osmotic action of glucose.

Allatotropin-like peptide in Malpighian tubules: insect renal tubules as an autonomous endocrine organ

Malpighian tubules (MTs) are recognised as the main excretory organ in insects, ensuring water and mineral balance. Haematophagous insects incorporate with each meal a large quantity of blood, producing a particularly large volume of urine in a few hours. In the present study, we report the presence of an allatotropin-like (AT-like) peptide in MTs of Triatoma infestans (Klug). The AT-like content in MTs decreased during the first hours after blood-intake, correlating with the post-prandial diuresis. In vivo artificial dilution of haemolymph showed a similar effect. Isolated MTs challenged with a diluted saline solution resulted in an autonomous and reversible response of the organ regulating the quantity of peptide released to the medium, and suggesting that MTs synthesise the AT-like peptide. While MTs are recognised as the target for several hormones, our results corroborate that they also have the ability to produce and secrete a hormone in an autonomous way.

Chronic high-NaCl intake prolongs the cardiorenal responses to central N/OFQ and produces regional changes in the endogenous brain NOP receptor system

Intracerebroventricular nociceptin/orphanin FQ (N/OFQ) produces cardiovascular depressor, diuretic, and renal sympathoinhibitory responses in conscious rats. These studies examined how a chronic high-NaCl intake alters these peptide-evoked responses and the activity of the endogenous central N/OFQ peptide (NOP) receptor system. In normotensive Sprague-Dawley rats fed a chronic (3-wk) high (8%)-NaCl diet, intracerebroventricular N/OFQ (5.5 nmol) produced prolonged bradycardic, hypotensive, and diuretic responses but failed to suppress renal sympathetic nerve activity. In a separate group of rats maintained on a high-NaCl diet, intracerebroventricular infusion of the NOP receptor antagonist UFP-101 significantly decreased urine output. At the tissue level, high-NaCl treatment of rats significantly increased NOP receptor density, without altering endogenous N/OFQ peptide levels in whole hypothalamus (control, 712 +/- 35 fmol/mg vs. 8% NaCl, 883 +/- 49 fmol/mg, P < 0.05) and paraventricular nucleus. Furthermore, in the hypothalamus, basal GTPgammaS binding was increased without altering the sensitivity of N/OFQ-stimulated G protein coupling. In contrast, in whole medulla and the ventrolateral medulla (VLM), high-NaCl treatment decreased NOP receptor density (medulla: control, 1,473 +/- 131 fmol/mg vs. 8% NaCl, 327 +/- 31 fmol/mg, P < 0.05) and endogenous N/OFQ peptide levels (medulla: control, 35.3 +/- 2 fmol/mg vs. 8% NaCl, 11.9 +/- 3 fmol/mg, P < 0.05), while increasing the sensitivity of G protein signaling pathways to N/OFQ stimulation. Together, these findings suggest that during a chronic high-salt intake, regional changes in the activity of the N/OFQ-NOP system in the brain may contribute to the tonic regulation of cardiovascular function and urine output and to the altered physiological responses to exogenous central N/OFQ.

Patients' perspectives of falling while in an acute care hospital and suggestions for prevention

Patient falls and falls with injury are the largest category of reportable incidents and a significant problem in hospitals. Patients are an important part of fall prevention; therefore, we asked patients who have fallen about reason for fall and how falls could be prevented. There were two categories for falls: the need to toilet coupled with loss of balance and unexpected weakness. Patients asked to be included in fall risk communication and asked to be part of the team to prevent them from falling. Nurses need to share a consistent and clear message that they are there for patient safety.