Plasma Levels Of Na Research Articles

Manipulation of growth of the Amazonian fish tambaqui, Colossoma macropomum (Characiformes: Serrasalmidae): analysis of physiological and zootechnical aspects

ABSTRACT Colossoma macropomum, known locally as tambaqui, is the native fish most farmed in Brazil, however, technological advances are needed to reach efficient production rates. Modulating growth factors, such as growth hormone, may be associated with improved growth rate and feed efficiency. The use of exogenous hormone for fish rearing is prohibited in Brazil, yet the experimental use of bovine hormone can be useful in research aimed at understanding how to stimulate endogenous growth hormones in fish. Therefore, the present study had the strict objective of understanding the effects of growth hormone on the physiology and zootechnical parameters of C. macropomum under experimental conditions. The animals were intraperitoneally injected every fifteen days with 1, 10 and 100 μg g-1 of bGH using 0.9% NaCl saline as diluent. The 10 and 100 μg g-1 bolus had a positive effect on the performance indexes of C. macropomum: weight gain (g), growing length (cm), daily weight gain (g), feed conversion and specific growth rate (% per day). The bGH promoted a greater increase in length than in mass, which caused a reduction in condition factor of the individuals receiving a bolus of 10 and 100 μg g-1. Furthermore, bGH caused no changes in glucose levels, cortisol, hematological parameters, plasma levels of Na+ and K+, and activity of gill’s H+-ATPase and Na+, K+-ATPase, at least during the experimental period considered in the present study.

Combined Administration of l-Carnitine and Ascorbic Acid Ameliorates Cisplatin-Induced Nephrotoxicity in Rats

ABSTRACTObjectives: Cisplatin (CIS) is an effective antitumor drug. However, its clinical use is limited due to nephrotoxicity. l-Carnitine and vitamin C are both natural antioxidant that can be obtained from diets. This study investigated the effects of l-carnitine and/or vitamin C in rats against cisplatin-induced nephrotoxicity.Methods: Twenty-five male Wistar rats were divided into 5 groups of 5 rats each. Group 1, normal control. Group 2, positive control, received cisplatin (10 mg/kg/day intraperitoneally [i.p.]) for 3 days. Groups 3, 4, and 5 received cisplatin for 3 days and thereafter l-carnitine (50 mg/kg/day), vitamin C (100 mg/kg/day), or their combination, respectively, for 28 days. At the end of the study, a biochemical study was carried out in which nephrotoxicity markers, electrolytes, hematological indices, oxidative stress biomarkers, and renal histopathological alterations were evaluated.Results: CIS-treated rats developed significant polyuria, increase in the plasma levels of creatinine, urea, and inorganic phosphate (Pi), alteration in hematological parameters, and decrease in plasma levels of Na+, Cl−, K+, Ca2+, and Mg2+. Measurements of 24-hour urine output demonstrated markedly decreased creatinine and urea and increased Na+, Cl−, K+, Ca2+, and Mg2+ levels in the CIS-treated group, whereas Pi levels were not changed. It also caused significantly decreased catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) levels in the rats' kidneys. Histopathological scores revealed renal tubular damage in CIS-treated rats. However, l-carnitine, vitamin C, or their combination significantly attenuated the alterations caused by CIS in the plasma and kidneys of the rats.Conclusion: l-Carnitine and vitamin C administration ameliorated CIS-induced nephrotoxicity due to their antioxidant and anti-inflammatory effects.

STATUS OF PLASMA ELECTROLYTES, UREA, CREATININE, AND C-REACTIVE PROTEIN IN CANCER PATIENTS.

Objective: Cancer is a major health problem not only in developed countries but also in developing countries like Nigeria. This study was designed to study the status of plasma electrolytes, urea, creatinine, and C-reative proteins (CRPs) in freshly diagnosed cancer patients.Methods: Plasma electrolytes (sodium [Na+], potassium [K+], chlorine [Cl-], and bicarbonate [HCO3-]), urea, creatinine, and CRP were estimated in four different types of cancer (liver, colon, cervical, and uterine) patients attending Ekiti State University Teaching Hospital Ado Ekiti Nigeria. A total of 250 patients (between age of 45 and 70 years) consisting of 50 patients in each cancer type and 50 normal subjects as control were considered in this study.Results: The result obtained revealed a significant (p<0.05) increase in the plasma levels of Na+, Cl-, creatinine, and CRP in all the cancer types when compared with the control subjects. Plasma urea level decreased significantly in patients with colon (3.16±0.70 mmol/L) and liver (3.03±1.75 mmol/L) cancer when compared with the control subjects (4.80±1.12 mmol/L). K+ and HCO3_ level was not significantly (p>0.05) different in all cancer types when compared with the control subjects.Conclusion: This study revealed a possible link between plasma electrolytes, creatinine, CRP, urea, and cancer which could be useful in the assessment and management of cancer.

STATUS OF PLASMA ELECTROLYTES, UREA, CREATININE, AND C-REACTIVE PROTEIN IN CANCER PATIENTS.

Objective: Cancer is a major health problem not only in developed countries but also in developing countries like Nigeria. This study was designed to study the status of plasma electrolytes, urea, creatinine, and C-reative proteins (CRPs) in freshly diagnosed cancer patients.Methods: Plasma electrolytes (sodium [Na+], potassium [K+], chlorine [Cl-], and bicarbonate [HCO3-]), urea, creatinine, and CRP were estimated in four different types of cancer (liver, colon, cervical, and uterine) patients attending Ekiti State University Teaching Hospital Ado Ekiti Nigeria. A total of 250 patients (between age of 45 and 70 years) consisting of 50 patients in each cancer type and 50 normal subjects as control were considered in this study.Results: The result obtained revealed a significant (p<0.05) increase in the plasma levels of Na+, Cl-, creatinine, and CRP in all the cancer types when compared with the control subjects. Plasma urea level decreased significantly in patients with colon (3.16±0.70 mmol/L) and liver (3.03±1.75 mmol/L) cancer when compared with the control subjects (4.80±1.12 mmol/L). K+ and HCO3_ level was not significantly (p>0.05) different in all cancer types when compared with the control subjects.Conclusion: This study revealed a possible link between plasma electrolytes, creatinine, CRP, urea, and cancer which could be useful in the assessment and management of cancer.

Plasma Calcium Concentration Modifies the Blood Sodium During Hemodialysis: Lessons from Hard Water Syndrome

Abstract Introduction. Extracellular sodium (Na+) concentration is maintained within a tight physiological range due to hormonal control, that mainly modulates thirst, Na+ and water renal excretion. Extra-renal regulation of Na+ and water homeostasis is only partially understood. Recently it has been debated whether the osmotically inactive Na+ storage is fixed or variable. Methods. In the present study, fourteen End-Stage Renal Disease (ESRD) patients treated by chronic hemodialysis underwent by accident to a sharp increase in plasmatic calcium (Ca+2) levels due to the failure of the water control system, leading to the so-called hard water syndrome. The levels of plasmatic Ca+2 after 1 hr of hemodialysis were correlated with urea, Na+, potassium (K+) and creatinine levels. Eleven ESRD patients treated with hemodialysis under similar conditions were used as controls. Results. The hard water syndrome resulted in hypercalcemia, while mean plasma levels of Na+, K+ and urea were not different compared to controls. Plasma creatinine levels were slightly but significantly higher that control. A correlation analysis on the measured variables has showed a positive correlation between plasma Ca+2 and Na+ levels (Pearson=0.428, p=0.032), and the absence of any correlation with K+, creatinine and urea concentration. Conclusions. Our study suggests that acute changes in plasmatic Ca+2 levels may affect Na+ concentration in the absence of renal function; it is possible that hypercalcemia may trigger Na+ release from the osmotically inactive storage. These data further support previous observations on the interplay of sodium and calcium at extrarenal sites.

Tolerance of piava juveniles to different ammonia concentrations

The objective of this study was to evaluate the tolerance of piavas (Leporinus obtusidens) to ammonia (NH3) by measuring its effects on plasma ion levels and tissue metabolic parameters. Piava juveniles (25-30 g) were exposed to five concentrations of NH3 (mg L-1): 0.003 (control), 0.1, 0.4, 0.7, and 1.4; after 96 hours, plasma levels of Na+, K+, Cl- and NH4+ ions and metabolic and enzyme activity in tissues (liver, kidneys, gills and muscle) were measured. The lethal concentration (LC50; 96h) of NH3 was 0.27 mg L-1. As NH3 increased, Na+ and NH4+ in the plasma increased and K+ decreased. In addition, Na+/K+- ATPase activity concomitantly increased in the gills and decreased in the kidneys. Glucose, glycogen, and protein levels decreased, while lactate and ammonia increased in the tissues of piava juveniles that were treated with higher concentrations of ammonia. The observed lethal toxicity could be due to a gradual depletion of plasma ion levels and a reduction of metabolic and Na+/K+-ATPase activity in tissues. Both can lead to dysfunction in ionoregulatory and physiological systems. This finding has implications for the management of fish culture of piavas.

Evaluation of the diuretic effects of crude stem bark extraction of Zanthoxylum heitzii (Rutaceae) in Wistar rats

ObjectiveZanthoxylum heitzii is a medicinal plant widely used in central Africa for the treatment of many diseases, especially cardiovascular diseases and hypertension. The diuretic effects of crude stem bark extraction were determined and its safety in rats was evaluated. MethodsThe diuretic effects of crude stem bark extraction of Z. heitzii were investigated in Wistar rats (250 g ± 10 g) of both sexes. The crude stem bark extraction of Z. heitzii at the doses of 225, 300 and 375 mg/kg was administered to rats at 5 mL/kg body weight. Urine volume was determined 1, 2, 3, 4, 5, 6 and 24 h after administration of the extract. Kinetics of electrolyte elimination in response to a single oral administration dose of acute treatment was measured. The experiments were performed under the same conditions with two synthetic pharmacological diuretics considered as reference (furosemide and hydrochlorothiazide). Urinary and plasma concentrations of sodium and potassium ions were determined using flame photometry. Concentrations of creatinine, urea, glucose, albumin and electrolytes in the plasma and urine samples were evaluated using a two-way digital bidirectional spectrophotometer. The osmolarity of plasma and urine samples was measured by cytometry using an osmometer. Aldosterone was measured by radioimmunoassay. ResultsThe plant extract accelerated the elimination of overloaded fluid and increased urine volume and the excretion of Na+, K+ and Cl− 24 h after administration (P<0.05). The increase in elimination of Na+, K+, and Cl− induced by the extract caused alkalinization of the urine, and showed a strong inhibitory effect on carbonic anhydrase and saluretic. These effects were mainly observed at the dose of 375 mg/kg. At the maximum diuretic response, urinary osmolarity decreased significantly (P < 0.05) when compared to controls. The stability of aldosterone level, the absence of correlation with the plasma levels of Na+, and increased clearance of free water in the animals treated with extract indicated that increased diuresis and natriuresis were tubular in origin. No significant (P > 0.05) changes were observed in the body temperature of the animals. ConclusionThe significant increase in urine volume 24 h after treatment followed a dose-response pattern. The excretion of Na+, K+ and Cl− caused a decrease in urine osmolarity. The stability of aldosterone, the absence of correlation with the plasma levels of sodium, and increased clearance of free water in animals treated with aqueous extract suggest that increased diuresis and moderate natriuresis elevation were of tubular origin.

Blood gas analysis in Mangalarga Marchador horses with colic

Objective. This study aims to distinguish blood gas changes in horses with colic syndrome in which small or large intestine is affected. Materials and methods. Thirty Mangalarga Marchador horses were assessed, divided into groups according to the affected intestinal segment in episodes of colic syndrome (ECS): a group (N=10) of horses suffering from ECS with lesions only in the small intestine, a group (N=10) of horses suffering from ECS with lesions only in the large intestine and a group (N=10) of healthy horses (control). All the animals with ECS were submitted to exploratory laparotomy in order to establish the intestinal segment affected. Blood samples were collected by venipuncture, before surgical procedure to determine sodium, potassium, chloride, urea, glucose, hematocrit, hemoglobin, pH, carbon dioxide partial pressure, total carbon dioxide concentration, bicarbonate, base excess and anion gap. Results. No significant changes were found in plasma levels of Na+, K+, Cl- , pCO2 and anion gap in any type of ECS. Horses with small intestine injuries presented higher levels of tCO2, urea and bicarbonate compared to those with large intestine injuries and to the control group, as well as higher levels of glucose and base excess than the control group. Conclusions. Horses with colic syndrome bearing small intestine injuries show wider variations in the blood gas parameters than horses with large bowel lesions. Key word: Acid-base imbalance, electrolytes, large intestine, small intestine (Source:CAB).

Serum electrolytes and lipid profiles in non-insulin dependent diabetes mellitus patients

Background: Diabetes mellitus and hyperlipidemia are the most common metabolic disorder affecting the people all over the world. Hyperglycemia is considered a primary cause of diabetic vascular complications and is associated with impaired electrolytes in some of the metabolic dysfunctions is not clear. Aim: The purpose of this study was conducted to investigate the relationship among diabetes mellitus, lipid profiles and electrolytes (Na+, K+ and Cl-). Methods: In the sera of 85 non insulin-dependent diabetes mellitus NIDDM, 45 with hyperlipidemia, 40 without hyperlipidemia, 50 samples of hyperlipidemia without NIDDM, and 50 non diabetic healthy control subjects. The mean age of the diabetic patients was similar to that of control. The mean duration of the disease was (10.2±5.9) years (2-23) years. From the results, it was discovered that there was a significant decrease in Na+ and Cl- in patients with NIDDM without high level of lipid profile (group I), but our results show that the concentration of K+ not changed significantly. The plasma levels of Na+ and Cl- ions were show significant change in patient with hyperlipidemia without NIDDM (group II), while plasma K+ not changed significantly in this group as compared with control. The mean value of Na+ and Cl- show high significant change in NIDDM patients with high level of lipids profile (group III),were plasma K+ not changed significantly as compared with control group. Conclusion: These finding may explain the role of impaired electrolytes status in NIDDM and hyperlipidemia subjects. DOI: http://dx.doi.org/10.3126/ajms.v6i3.11088Asian Journal of Medical Sciences Vol.6(3) 2015 38-41

Kidney Function Status in Nigerian Human Malaria Patients

Malaria is now known to affect over 500 million persons worldwide, killing about 1 to 3 million of them annually. Plasmodium falciparum is the species mostly implicated in the causation of severe malaria. This study was carried out to investigate the kidney function status of malaria patients in Benin metropolis, Southern Nigeria, to ascertain if there is renal dysfunction/impairment in them. Plasma levels of sodium, potassium, bicarbonate, urea, creatinine and blood urea nitrogen (BUN) were assayed in a total of 152 subjects (112 malaria patients infected with Plasmodium falciparum and 40 controls) of both sexes, with their age ranging from 8 to 42 years. The results observed irrespective of age or sex, reveal a statistically significant (p<0.05) increase in plasma levels of potassium, urea, BUN and creatinine (4.49±0.95 mmol/L;5.88±0.13mmol /L;16.39±0.36mg/dl and 135.05±2.69imol/L) when compared to their controls (4.05±0.34mmol/L;3.73±0.12mmol/L;10.34±0.36mg/dl and 80.71±1.69imol/L, respectively) and also a statistically significant (P<0.05) reduction in plasma levels of Na+ and HC03- (128.50±0.77 and 19.98±0.28mmol/L) when compared to their controls (l38.58±0.29 and 24.70±0.36mmol/L, respectively). The hyponatraemia and metabolic acidosis observed in the malaria patients are negatively correlated with the degree of parasitaemia (r=-0.241 and r=-0.019, respectively), while the elevated plasma potassium and creatinine levels are positively correlated with the degree of parasitaemia (r=0.153 and r=0.407, respectively). The elevated plasma Urea and BUN levels are also positively correlated with the degree of parasitaemia (r=0.371 and r=0.375, respectively). The results of this study indicate that there is significant renal dysfunction/impairment in patients in southern Nigeria infected with plasmodium falciparum. Keywords : Malaria infection, Kidney function status.

Anesthesia and transport of fat snook Centropomus parallelus with the essential oil of Nectandra megapotamica(Spreng.) Mez

This study analyzed the chemical composition and anesthetic potential of essential oil (EO) of Nectandra megapotamica in fat snook (Centropomus parallelus). For the extraction of EO by hydrodistillation, leaves were separated in young (EO-Y) or old (EO-O), and the chemical composition of the EOs was determined by CG-MS. The anesthetic potential was assessed by the evaluation of induction and recovery time of anesthesia and stress response from anesthesia and transport. Three experiments were carried out: i) four different concentrations of each EO were tested to evaluate anesthesia induction and recovery time; ii) two concentrations of EO-O were tested for the evaluation of its effects on stress parameters (glucose, lactate, and Na+ and K+ plasma levels) caused by anesthesia; and iii) fish were transported in plastic bags, supplied with two concentrations of EO-O for the evaluation of water quality and mortality. All experiments were performed on fish acclimated to 0 and 33 ppt salinity. The main constituents of the Y and O-EOs were bicyclogermacrene (46.5/34.6%), α-pinene (26.8/26.2%), β-pinene (7.9/12.3%), and germacrene D (9.6/9.1%). Mild sedation was achieved at 30 °L L-1(1.3-3.2 min) and deep anesthesia at 150 °L L-1(5.6-8.0 min) with both EOs. The recovery time ranged from 1-10 min. The EO-O was not able to avoid the stress of anesthesia evidenced by elevated glucose and lactate plasma levels observed in all groups. Plasma levels of Na+ and K+ were not significantly affected by treatments. During transport, the use of EO-O did not prevent deterioration in water quality and the post-transport mortality. In conclusion, the EO of N. megapotamica has anesthetic activity in fat snook, but it was not able to prevent the stress of anesthesia and transport.

The Effect of Copper and Lead on Oreochromis niloticus and Cyprinus carpio in Blood Ion Level

In this study, the effects of concentration and exposure time of Cu and Pb on plasma levels of Na+, K+, Ca++, Mg+ and C-l of Cyprinus carpio and Oreochromis niloticus were tested at varying concentrations of metal in the medium and over different periods of time. Fish were exposed to 0.1, 0.5 and 1.0 mg/L Cu and Pb over periods of 10 and 20 days and ion distributions of copper and lead were determined using spectrophotometric method. Plasma ion (Na+, K+, Ca++, Mg and Cl-) levels effected by Pb and Cu. In both species, blood serum Na + levels decreased after periods tested at exposure to copper while increasing at exposure lead. O. niloticus blood serum K + levels increased with effect of Cu and Pb concentrations. In C. carpio Cu concentrations blood serum K+ levels increased while decreased with effect of Pb concentrations after 10 and 20 days of exposure. Ionize Ca++ levels of blood serum in O. niloticus decreased

Does the presence of a seawater gill morphology induced by dietary salt loading affect Cl− uptake and acid–base regulation in freshwater rainbow trout Oncorhynchus mykiss

The goal of this study was to determine the effect of the changes in gill morphology induced by dietary salt feeding on several aspects of gill function in rainbow trout Oncorhynchus mykiss maintained in fresh water with specific emphasis on Cl(-) uptake (J(IN)Cl(-)) and acid-base regulation. The addition of 11% NaCl to the diet caused J(IN)Cl(-) to be reduced by c. 45% from 214·4 ± 26·7 to 117·3 ± 17·4 µmol kg(-1) h(-1) (mean ± s.e.). Rates of Cl(-) efflux (J(OUT)Cl(-)), net Cl(-) flux (J(NET)Cl(-)), J(NET) Na(+) and plasma levels of Na(+) or Cl(-) were unaffected by salt feeding. On the basis of significant effect of the salt diet on decreasing the maximal uptake rate of Cl(-)(J(MAX)Cl(-)), it would appear that internal salt loading caused a decrease in the number of functional ion transport proteins involved in Cl(-) uptake (e.g. Cl(-) -HCO(3)(-) exchangers) and decreased the transporting capacity of existing proteins. The acid-base regulating capacity of control fish and salt-loaded fish was assessed by monitoring arterial blood acid-base status [partial pressure of CO(2) (PCO(2)), pH and HCO(3)(-)] during exposure to external hypercapnia (nominally 7·5 mm Hg). Both groups of fish exhibited typical compensatory responses to sustained hypercapnia consisting of the gradual accumulation of plasma HCO(3) (-) and thus metabolic restoration within 24 h of the initial respiratory acidosis elicited by hypercapnia. Overall, the results demonstrate that while Cl(-) uptake capacity is reduced in salt-fed fish, there is no associated alteration in acid-base regulating capability.

Angiotensin-(1–7) reduces proteinuria and diminishes structural damage in renal tissue of stroke-prone spontaneously hypertensive rats

Angiotensin (ANG)-(1-7) constitutes an important functional end-product of the renin-angiotensin-aldosterone system that acts to balance the physiological actions of ANG II. In the kidney, ANG-(1-7) exerts beneficial effects by inhibiting growth-promoting pathways and reducing proteinuria. We examined whether a 2-wk treatment with a daily dose of ANG-(1-7) (0.6 mg·kg(-1)·day(-1)) exerts renoprotective effects in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP). Body weight, glycemia, triglyceridemia, cholesterolemia, as well as plasma levels of Na+ and K+ were determined both at the beginning and at the end of the treatment. Also, the weekly evolution of arterial blood pressure, proteinuria, and creatinine clearance was evaluated. Renal fibrosis was determined by Masson's trichrome staining. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, and nuclear factor-κB (NF-κB) levels were determined by immunohistochemistry and confirmed by Western blotting analysis. The levels of glomerular nephrin were assessed by immunofluorescence. Chronic administration of ANG-(1-7) normalized arterial pressure, reduced glycemia and triglyceridemia, improved proteinuria, and ameliorated structural alterations in the kidney of SHRSP as shown by a restoration of glomerular nephrin levels as detected by immunofluorescence. These results were accompanied with a decrease in both the immunostaining and abundance of IL-6, TNF-α, and NF-κB. In this context, the current study provides strong evidence for a protective role of ANG-(1-7) in the kidney.

Influence of morphine treatment in pregnant rats on the mineralocorticoid activity of the adrenals in their neonates

Exposure of pregnant rats to morphine, from day 11 to day 18 of gestation, was previously reported to induce both an adrenal atrophy and hypoactivity of the glucocorticoid function in newborns at term, but did not affect, in vitro, the responsiveness of those glands to adrenocorticotrophin hormone (ACTH) concerning corticosterone release. Moreover, these effects were mediated by maternal hormones from the adrenal glands. In the present work, we investigated the effects of a prenatal morphine exposure on the mineralocorticoid activity of the adrenals in neonates. The first aim of the present study was to determine in these newborns 1∘) the adrenal and plasma aldosterone concentrations at birth time and during the early postnatal period 2∘) the plasma levels of Na + and K + at birth time, 3∘) the in vitro responsiveness of the newborn adrenals to angiotensin II (A II) and ACTH. The second aim of our study was to investigate the mineralocorticoid activity of the adrenals in newborns from adrenalectomized mothers treated with morphine during gestation. According to present data morphine given to intact mothers induced in newborns a severe adrenal atrophy but increased adrenal aldosterone content and plasma aldosterone level. However, prenatal morphine was unable to affect significantly Na+ K+ ratio in both mothers and newborns. In vitro, the adrenals of neonates from morphine-treated mothers were unresponsive to A II and ACTH for promoting aldosterone release; in contrast, aldosterone secretion was significantly stimulated by high potassium levels (55 mEq). Maternal adrenalectomy performed one day before the beginning of morphine treatment prevented morphine-induced adrenal atrophy but was unable to affect significantly the adrenal mineralocorticoid function of the offspring. Such data suggest that a prenatal morphine exposure stimulated both aldosterone synthesis and release in neonates. However, this basal hyperfunction did not appear to be coupled with an enhanced adrenal responsivity to AII or ACTH. Prenatal morphine-induced hyperactivity of the mineralocorticoid function of the newborn adrenals, which drastically contrast with hypoactivity of the glucocorticoid one, was independent of adrenal factors from maternal origin.

Effects of dietary magnesium supplementation on diurnal variations of blood pressure and plasma Na+, K(+)-ATPase activity in essential hypertension.

To evaluate the antihypertensive and hormonal effects of oral magnesium supplementation, 17 inpatients with untreated, uncomplicated mild-to-moderate essential hypertension (EH) and 8 age-matched normotensive controls (controls) were given MgO orally 3 times a day at a daily dose of 1.0 g (0.6 g per day as Mg) for a period of 2 weeks. Supplementation of MgO elicited a significant fall in averaged mean blood pressure calculated with a 24-h ambulatory blood pressure monitoring system (MBP) in EH from a baseline value of 104.3 +/- 12.2 to 99.5 +/- 11.6 mmHg (p < 0.05), while controls remained unaltered from a baseline value of 85.1 +/- 11.5 to 84.5 +/- 13.3 mmHg. The percentage reductions in systolic and diastolic blood pressures were similar during daytime and nighttime in EH. According to the extent of reduction in MBP with magnesium supplementation, EH patients were divided into 2 groups, responder and nonresponder. The level of plasma renin activity (PRA) in the responder group was significantly higher than that of the nonresponder group (p < 0.05). After 2 weeks of magnesium supplementation, the plasma level of Na+, K(+)-ATPase inhibitory activity (PATPI), defined as equivalency to ouabain, was reduced significantly from 0.75 +/- 0.54 to 0.40 +/- 0.30 mumol ouabain/ml (p < 0.05) in the responder group, while it remained unaltered in controls and the nonresponder group. PRA, plasma aldosterone concentration, urinary epinephrine and norepinephrine excretion, and urinary sodium excretion did not change significantly in either control subjects or EH (responder and nonresponder groups). A significant negative correlation existed between the pretreatment PRA and changes in MBP after magnesium supplementation in EH (r = -0.65, p < 0.01), and there was a significant positive correlation between changes in PATPI and changes in MBP as a whole (r = 0.41, p < 0.05). These results support the view that oral magnesium supplementation is a useful approach to treatment of patients with uncomplicated essential hypertension, especially those with high plasmas renin activity. It appears that magnesium suppresses circulating Na+,K(+)-ATPase inhibitory activity to attenuate vascular tone, and thereby reduces blood pressure in EH.

Mercury from dental "silver" tooth fillings impairs sheep kidney function

In humans Hg vapor is released from "silver" amalgam fillings that contain 50% Hg by weight. Previous studies show that when 12 such fillings are placed in sheep teeth, the kidneys will concentrate amalgam Hg at levels ranging from 5 to 10 micrograms Hg/g renal tissue 4-20 wk after placement. In the present study 12 occlusal fillings were placed in each of six adult female sheep under general anesthesia, using standard dental procedures. Glass ionomer occlusal fillings (12) were inserted in two control sheep. At several days before dental surgery, and at 30 and 60 days after placement of fillings, renal function was evaluated by plasma clearance of inulin and by plasma and urine electrolytes, urea, and proteins. An average plasma inulin clearance rate of 69.5 +/- 7.2 ml/min before amalgam placement was reduced to 32.3 +/- 8.1 ml/min by 30 days and remained low at 27.9 +/- 8.7 ml/min after 60 days. Inulin clearance did not change in controls. After amalgam placement urine concentration of albumin decreased from 93.0 +/- 20.5 to 30.1 +/- 15.3 mg/l and urine Na+ concentration increased steadily from 24.8 +/- 7.7 to 82.2 +/- 20.3 mmol/l at 60 days. Concentrations of K+, urea, gamma-glutamyl transpeptidase, alkaline phosphatase, and total protein did not change significantly from 0 to 60 days in urine. Plasma levels of Na+, K+, urea, and albumin remained unchanged from 0 to 60 days after amalgam. Renal histology remained normal in amalgam-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of rapid changes in salinity on the osmoregulation of postsmolt Atlantic salmon ( Salmo salar)

Blood parameters in postsmolt Atlantic salmon were studied during artificial introduction of abrupt salinity changes between 34% and 10 and 5‰. Mortality in the test groups did not increase compared to the control group. Plasma levels of Na + and Cl − were significantly decreased in the low-salinity periods. Plasma levels of Mg 2+ and haematocrit were significantly increased during low salinity, and plasma levels of K + were not significantly affected by the changes in salinity. This experiment indicates that salinity changes alone will not cause heavy mortality in fjord-based salmon farms, but salinity changes in combination with other environmental factors may represent a stress situation for postsmolt Atlantic salmon.

Effects of pyrethroid insecticides on subjects engaged in packaging pyrethroids.

A health survey was conducted on 199 workers engaged in dividing and packaging pyrethroids. The subjects were exposed to fenvalerate at 0.012-0.055 mg/m3 and deltamethrin at 0.005-0.012 mg/m3 in the air with simultaneous skin contact for 0.5-4.5 months. Burning sensations and tightness or numbness on the face appeared in two thirds of the subjects and one third had sniffs and sneezes. Abnormal facial sensations, dizziness, fatigue, and miliary red papules on the skin were more evident in summer than in winter. Neither abnormalities in other organs or systems nor symptoms or signs of acute pyrethroid poisoning were found by interviews, examinations, and laboratory tests. There was no significant difference in plasma levels of NA, cAMP, and cGMP between the examined subjects and the control group. The urine concentration of fenvalerate in the study group ranged from 1.02 to 18.6 micrograms/l; deltamethrin in the urine was present in trace amounts.

Concentration of adrenocortical hormones in relation to cation homeostasis in birds.

The effects of dietary Na+, K+, and Cl- and of acute stress on plasma levels of Na+, K+, aldosterone, and corticosterone were evaluated in vivo in birds. The dietary effects were studied in growing White Rock chicks, whereas the larger turkey was preferred for the acute stress study. Although plasma corticosterone remained unaffected, plasma aldosterone concentration decreased with increasing levels of dietary Na+ reaching a minimum at a dietary level of 72 meq/kg. Plasma Na+ remained unchanged when dietary Na+ levels increased up to 72 meq/kg but then rose with increasing Na+ intake. Plasma K+ was slightly depressed by high levels of dietary Na+ and increased by dietary K+. Neither plasma Na+ nor circulating adrenal hormones were affected by dietary K+ or dietary Cl-. Acute stress stimulated both aldosterone and corticosterone without any effect on the levels of the plasma minerals. The results suggest that of the two main corticoids, only aldosterone responds to dietary Na+ in chicks. This is in contrast to the indiscriminate stimulation of both hormones by stress, indicating different pathways of stimulation. The results also suggest that aldosterone is involved in the regulation of plasma Na+ only at low intakes of Na+ and that dietary K+ and Cl- are not involved in the aldosterone-Na+ feedback relationship.