Cumulative Balance Research Articles

Antidiuretic hormone infusion reduces taurine and NaCl-induced hypernatremia in the rat.

Rats drinking taurine and hypertonic saline (T + S) develop severe hypernatremia, but rats drinking either T or S alone do not. One hypothesis for this disruption of homeostasis is that the T + S combination interferes with the actions of antidiuretic hormone (ADH). Rats drinking T + S developed severe hypernatremia (170 mmol/L) by day 8 when infused with distilled water by osmotic minipumps, but maintained plasma sodium below 150 mmol/L when infused with ADH. Cumulative water balance in T + S drinkers receiving ADH was consistently higher than in those not receiving ADH. However the ratio of cumulative sodium balance to cumulative water balance suggests little uniform advantage to rats receiving ADH nor does comparison of urine osmolality in the two groups. Precisely how ADH administration reduces hypernatremia in T + S drinking rats remains unclear, but the hypothesis that T + S interferes with the action of ADH in its regulation of extracellular fluid volume and osmolality remains viable.

97/03091 Development of cumulative and availability rate balances in a multi-cylinder turbocharged indirect injection diesel engine

97/03091 Development of cumulative and availability rate balances in a multi-cylinder turbocharged indirect injection diesel engine

The Blood Balance of Very Low Birth Weight Infants 1282

Objectives: To find the factors affecting blood loss and transfusions in VLBW infants and calculate their blood balance.Method: A retrospective medical records survey. Results:(All results are mean values) The survey included 110 medical records of VLBW infants who lived > 48 hrs in the NICU. Exclusion criteria: Need for surgery, hemolytic disease, congenital anemia and requirement of exchange transfusion. Blood volumes drawn for tests in the first 8 wks of life or until death or discharge were calculated as red blood cell volumes (RBCV) according to volume drawn and daily hematocrit (Htc). Initial RBCV was calculated according to initial Hct and mean blood volume of 80 ml/Kg BW. Standard transfusion Htc was 70%. Physiologic 1.5% daily blood destruction was included in the calculation of daily and cumulative balances of RBCV/Kg. Balances were calculated for various diagnosis, BW and GA groups. In the first 8 wks of life a mean of 282 blood samples for laboratory test in a RBCV of 37 ml were drawn from each VLBW baby. At the same time a mean of 4.7 blood transfusions from different donors were given in a volume of 59.6 ml. In the ELBW (<1000 gram), in infants born <30 wks GA or those suffered of sepsis or RDS significantly more blood volume and more tests were drawn. In the first two wks of life blood balance was maintained more strictly. During the subsequent 5 wks RBCV transfused was significantly higher than the volume drawn for blood tests. Anemia developed in the first 2 wks was related to blood tests whereas that in the next 5 wks was the result of a fast gain in body weight. Half of the blood taken for laboratory tests during hospitalization was drawn in the first 2 wks. The best predictors of the need for blood transfusions were RDS, rate of weight gain, GA at birth and the RBCV drawn for tests. Mean Htc levels before transfusion in the first 2 weeks of life was significantly higher than the level in the subsequent 5 wks of hospitalization. BW and RDS did not change significantly pretransfusion Hct levels. Conclusions: Blood tests are the main cause of anemia in the first 2 wks. At that time blood drawn equals the volume taken in the subsequent 5 wks. In ELBW and sick infants blood balance is maintained more strictly. During convalescence the main cause of anemia is rapid growth.

Effect of aldosterone on renal potassium conservation in the rat.

The importance of reduced plasma aldosterone concentration (PAC) in renal potassium (K) conservation is unclear. Thus we examined the effect of aldosterone on incipient, developing, and established renal K conservation. Adrenalectomized (ADX) dexamethasone-replaced rats were continuously treated with high, normal, or low dosages of aldosterone during 4 days of dietary K restriction and were compared with rats without aldosterone replacement. High and normal aldosterone replacement reduced the fall in urinary K excretion and led to significantly lower plasma [K], skeletal muscle tissue K content, renal tissue K content, and greater negative cumulative balance of K compared with low aldosterone replacement. Likewise, plasma [K] and skeletal muscle tissue K content were significantly less in intact rats after 3 days of K deprivation and chronic treatment with aldosterone. Acute aldosterone treatment significantly increased urinary K excretion by isolated perfused kidneys. We conclude that incipient, developing, and established renal K conservation is not independent of mineralocorticoid activity and that the rapid fall in PAC during K depletion is necessary for maximal renal K conservation.

Cumulative balance testing of logic circuits : KRISHENDU CHAKRABARTY and JOHN P. HAYES. IEEE Transactions on Very Large Scale Integration (VLSI) System, 3(1), 72 (March 1995)

Cumulative balance testing of logic circuits : KRISHENDU CHAKRABARTY and JOHN P. HAYES. IEEE Transactions on Very Large Scale Integration (VLSI) System, 3(1), 72 (March 1995)

Cumulative balance testing of logic circuits

We present a new test response compression method called cumulative balance testing (CBT) that extends both balance testing and accumulator compression testing. CBT uses an accumulated balance signature, and it guarantees very high error coverage (over 99%) for various error models. We demonstrate that the single stuck-line (SSL) fault coverage of CBT for many of the ISCAS 85 combinational benchmark circuits is 100%, and for all but one circuit, the fault coverage is over 99.5%. To make processor circuits self-testing, any existing accumulators and counters can be exploited to implement CBT. Its ease of implementation, provably high error coverage, and exceptionally high SSL fault coverage, even with reduced (nonexhaustive) test sets, make CBT suitable for the built-in self testing of processor circuits that require a guaranteed level of test confidence.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Influence of calorie source on the physiological response to parenteral nutrition in malnourished rabbits

The present study was designed to investigate whether calorie source influences sodium and water metabolism and sympathetic activity during parenteral nutrition (PN). 20 New Zealand rabbits were starved until a mean weight loss of 18% was achieved and then re-fed for 6 days with 2 formulae of PN with different glucose-fat proportions. In the Glucose group (n = 9), 70% of non-protein calories were given as glucose while in the Lipid group (n = 11), 70% of non-protein calories were administered as lipids. Rabbits with a high glucose intake showed significantly higher weight gain (151 ± 87 vs. 52 ± 7 g, P = 0.01), water cumulative balance (542 ± 132 vs. 411 ± 87 ml; P = 0.02) and urinary metanephrine excretion (0.42 ± 0.12 vs. 0.30 ± 0.1 μmol/d, P = .03). Only in this group, urinary metanephrines correlated positively with water and sodium balances (r2 = 0.6; P = 0.02 and r2 = 0.7; P = 0.009 respectively). The Glucose group showed 2 different responses and in a second experiment 10 additional rabbits were added to this group to allow a statistical analysis of the response pattern: half of the animals increased their extracellular water (ECW) compartment while the remaining animals did not. The former group had higher sodium balance (13.9 ± 8 vs. 4.3 ± 5; P = 0.004) and wet lung weight (8.9 ± 0.9 vs. 7.9 ± 0.8; P < 0.05) after re-feeding and, at the beginning of PN, their serum aldosterone concentration were also higher (221 ± 11 vs. 130 ± 47 pmol/l; P < 0.05). In conclusion, glucose based PN appears to increase sympathetic activity and induce spurious weight gain due to markedly positive wate and sodium balances. Plasma aldosterone concentration at the end of starvation period influences sodium retention and ECW expansion during high glucose re-feeding.

Validity of bioelectrical-impedance analysis in measuring changes in lean body mass during weight reduction

The aim of this study was to investigate the validity of bioelectrical-impedance analysis (BIA) in measuring changes in lean body mass (LBM) that occur in the treatment of obesity with very-low-calorie diets (VLCDs). Resistance (R), reactance (Xc), and nitrogen balance (BN) were measured for 28 consecutive days in 16 obese women consuming isocaloric and isonitrogenous ketogenic and nonketogenic liquid VLCDs while housed in a metabolic ward. Changes in LBM were calculated by using eight BIA-predictive equations and from cumulative BN. Changes in LBM calculated by BN were larger in the ketogenic than in the nonketogenic diet (1.5 +/- 0.1 vs 0.6 +/- 0.2 kg/28 d, P less than 0.05). Neither R nor Xc changed significantly during treatment with either diet but each equation showed losses of LBM with time. All the equations overestimated the losses in LBM calculated by BN. BIA does not appear to be a valid method for measuring the small losses in LBM that occur during treatment of obesity with VLCDs.

Atrial natriuretic peptide and exercise-induced fluid retention in man

Previous studies have shown that day-long hill walking exercise results in significant sodium and water retention, followed during a recovery/rest period by natriuresis and diuresis. The purpose of this study was to assess the role of atrial natriuretic peptide (ANP) during the post-exercise natriuretic phase. Five subjects ate a fixed diet for 13 days. A period of 4 rest days preceded 5 days of strenuous hill walking, followed by a 4-day recovery period. Daily measurement of aldosterone, ANP and haematocrit, and sodium and water balances were performed. Exercise was associated with sodium retention and a positive cumulative balance, mean 268 mmol (SD 17) after 5 days. There was a mean cumulative positive water balance of 700 ml (sd 34). Haematocrit was reduced from 44.6% to 39.3%, indicating an increase in plasma volume of 22%. Plasma aldosterone concentration during exercise was elevated. Plasma ANP concentrations were raised significantly throughout the exercise period (mean 20.3 pmol I −1 [sd 6.4], control 9.4 pmol I −1 [sd 5.4], P −1 [sd 9.1]) but levels were significantly higher than control ( P

ANF and postprandial control of sodium excretion in dogs with compensated heart failure

The changes in plasma immunoreactive atrial natriuretic factor (iANF) and urinary Na excretion that occur in response to an oral load of Na and to infusion of synthetic atrial natriuretic factor (ANF) were examined in conscious dogs with an arteriovenous (AV) fistula and chronic compensated high-output heart failure. After ingestion of a meal containing 125 meq Na, plasma iANF and right atrial pressure increased from high basal levels of 506 +/- 46 pg/ml and 96 +/- 5 mmH2O to peak responses of 728 +/- 43 pg/ml (P less than 0.05) and 104 +/- 6 mmH2O (P less than 0.05). These increases were associated with a brisk postprandial natriuresis and diuresis of a magnitude previously observed in normal dogs. Synthetic ANF infusions that achieved plasma iANF levels of similar and higher magnitude to those observed during the feeding experiments did not produce a significant natriuresis in these AV fistula dogs. In separate series of experiments, chronic effects of normal and low-Na diets on daily Na excretion and postabsorptive plasma iANF, renin, and aldosterone were studied in normal and AV fistula dogs. During the normal Na diet of 40 meq/day, both groups had normal levels of renin and aldosterone, but Na balance was achieved in AV fistula animals in the presence of a fourfold elevation in plasma iANF compared with normal dogs (P less than 0.05). During 2 wk of Na restriction, cumulative negative Na balance and marked stimulation of renin and aldosterone were similar in normal and AV fistula animals, but plasma iANF did not change significantly in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the Splanchnic Tissues in the Pathogenesis of Altered Carbohydrate Metabolism in Patients with Chronic Renal Failure

To evaluate the contribution of the splanchnic area to the carbohydrate abnormalities associated with chronic uremia, the splanchnic exchange of glucose and gluconeogenic substrates was quantitated basally and after an iv glucose load in nine uremic patients with impaired glucose tolerance and seven control subjects. In the basal state, blood glucose and splanchnic glucose production were similar in the two groups. During glucose infusion (33 mumol/kg.min for 90 min), blood glucose reached significantly higher levels in the uremic patients than in controls (P less than 0.02). Plasma insulin increased slightly more in uremic patients than in controls (P less than 0.05 at 15 min). Both basal and postglucose glucagon levels were 2- to 3-fold higher in uremic patients than in normal subjects (P less than 0.05-0.02). In both groups, splanchnic glucose balance switched from net output in the basal state (-9.4 +/- 0.5 and -8.0 +/- 1.1 mumol/kg.min in normals and uremics, respectively) to net uptake with glucose infusion. However, this response was less marked in the uremic patients than in normal subjects (P less than 0.05-0.02 at 30 and 90 min). The cumulative net splanchnic glucose balance over the 90-min study period was 538 +/- 55 mumol/kg in normal subjects and 279 +/- 89 in uremic subjects (P less than 0.05). A net splanchnic lactate uptake was present in the basal state in normal (4.2 +/- 0.5 mumol/kg.min) and uremic subjects (3.4 +/- 0.5). During glucose infusion, in normal subjects splanchnic lactate exchange switched to a net output (-4.0 +/- 1.6 mumol/kg.min), whereas in the uremic group it remained as a net uptake (1.1 +/- 0.7) throughout the study period. Splanchnic gluconeogenic amino acid uptake was similar in the two groups in the basal state (1.8 +/- 0.1 mumol/kg.min and 2.2 +/- 0.2 in normal and uremic subjects, respectively). Glucose infusion caused a marked fall in amino acid uptake by liver in normal subjects, whereas no change was observed in the uremic group (0.9 +/- 0.3 and 1.9 +/- 0.2 mumol/kg.min, respectively). Splanchnic glycerol uptake was not different in the two groups in the basal state (0.75 +/- 0.2 and 1.1 +/- 0.2 mumol/kg.min) and decreased to a similar extent during glucose infusion. We conclude the following. 1) In uremic patients with glucose intolerance but normal fasting glycemia, the splanchnic metabolism of glucose and gluconeogenic substrates is normal in the postabsorptive state.(ABSTRACT TRUNCATED AT 400 WORDS)

Control of sodium excretion in NE-ACTH hypertension: role of pressure natriuresis.

The purpose of this study was to test the hypothesis that, in the presence of high circulating catecholamines, ACTH decreases renal excretory capability and that its natriuretic effects are caused by increased renal arterial pressure (RAP). In six conscious dogs, norepinephrine (NE, 0.4 micrograms.kg-1.min-1) alone for 5 days caused a small but significant rise in arterial pressure (AP) from 102 +/- 6 to 115 +/- 8 mmHg. An infusion of ACTH (600 micrograms/day) for 7 days, superimposed upon the NE, caused a further rise in AP to a plateau of 143 +/- 9 mmHg after 5 days while cumulative sodium balance fell to -149 +/- 41 meq by the 7th day. Cumulative water balance fell to -660 +/- 232 ml by the 3rd day and then increased slightly. In contrast, when ACTH infusion was repeated during NE infusion while RAP was prevented from increasing using a servo-controlled aortic occluder, cumulative sodium balance increased to 197 +/- 35 meq and AP rose from 108 +/- 5 to 168 +/- 5 mmHg after 7 days and did not plateau. Cumulative water balance rose to 2,325 +/- 445 ml. Thus, in dogs receiving a background infusion of NE, ACTH causes moderate hypertension and natriuresis. However, when RAP is not allowed to rise, ACTH is associated with sodium retention and severe systemic hypertension, suggesting that the natriuretic effects of ACTH are caused by increased RAP and that the natriuresis blunts the chronic hypertensive effects of ACTH.

Effect of phosphorus and potassium fertilizer on crop response and soil fertility in a long-term experiment

Data from 32 years of a rotation-fertility experiment were analyzed to determine the average P and K application rates required for maximum yield and for optimum yield. A four-year rotation of corn, soybean, wheat, hay was used for the first 10 years and then changed to corn-1, soybean, wheat, corn-2. Rates of P application per 4-year rotation ranged from 0 to 196 kg ha−1 and for K from 0 to 558 kg ha−1. Multiple regression equations were fitted to the mean yields per 4-year rotation for the response of each crop to P and K applications. The range in P application rates in kg of P per 4-year rotation required to get maximum yields of corn was 118 to 172, for soybeans was 134 to 150, and for wheat was 116 to 138. The range in K application rates in kg K per 4-year rotation to get maximum yields of corn was 378 to 411, for soybeans was 324 and 476, and for wheat was 11 to 323. For rates of application where P and K added exceeded crop removals, soil test P and K increased linearly with the cumulative positive balance of P and K. Where crop removal exceeded application rate, no relation was found between crop removal and soil test.

Effects of indomethacin on renal response to atrial natriuretic peptide.

We studied the effect of alpha-human natriuretic peptide (ANP, 100 micrograms iv) on renal sodium handling in eight healthy subjects before and after 7 days of indomethacin (50 mg 3 times a day). Sodium intake was 100 mmol/day. Prior to indomethacin, ANP caused a fourfold rise in sodium excretion over the first 20 min and a threefold rise in fractional sodium excretion. The clearance studies, performed during maximal water diuresis, showed increased fractional free water clearance and lithium clearance. Indomethacin caused marked sodium retention. Complete escape did not occur until the sixth day, when cumulative balance was 244 mmol (range 176-337). By this time renin and aldosterone were suppressed and fractional lithium and free water clearance reduced. The natriuretic effect of ANP was not attenuated, and the fractional excretion of sodium and chloride rose even more than without indomethacin. The reduction in lithium and free water clearance under indomethacin tended to be reversed by ANP. These data suggest that the natriuretic effect of ANP is not mediated by or dependent on renal prostaglandins. Indomethacin and ANP appear to have opposite effects on sodium excretion, maximal free water clearance, and lithium clearance.

Sodium excretion in dogs with low-grade caval constriction: role of hepatic nerves.

Low-grade thoracic caval constriction will raise intrahepatic pressure without driving fluid from the vascular space as ascites. In eight such dogs where venous pressure was increased by 6.6 cmH2O, sodium balance studies showed a positive cumulative balance of 85 meq and a weight gain of 480 g over a 6-day period in the absence of any change in renal perfusion, glomerular filtration rate, central venous pressure, blood pressure, cardiac output peripheral vascular resistance, or plasma levels of aldosterone. Liver function tests, including bromosulfophthalein disappearance curves, were also normal. In dogs with either sham surgery, or subjected to equivalent venous hypertension of the abdominal vena cava or portal veins, there was a cumulative positive sodium balance of only 21-28 meq over a 2-day period. When the liver was completely denervated prior to performing the thoracic caval constriction, the sodium handling profile reverted to the same pattern as observed in sham controls, i.e., 22 meq cumulative sodium over a 3-day period. When the thoracic caval constriction was tightened to produce ascites, a LeVeen valve was inserted and the ascites mobilized. In response to 130 meq/day sodium diet, denervated dogs excreted the sodium load normally, whereas dogs with intact hepatic nerves retained sodium and developed anasarca. We conclude that intrahepatic baroreceptors may modulate sodium excretion in the presence of intrahepatic hypertension.

Uses and limitations of the balance technique.

Classical balance techniques are a powerful, sensitive, and usually accurate technique for assessing the nutritional or metabolic response to changes in nutritional intake or to metabolic or physiological perturbations. Balances are particularly sensitive for examining transient or short-term responses to nutritional or metabolic stimuli. A major factor responsible for the precision and sensitivity of this technique is the precise control of the activities and environment of an individual during a classical metabolic balance study (eg, the carefully defined dietary intake, degree of exercise, and environmental temperature to prevent sweating); these same factors may enhance the precision and sensitivity of other metabolic or nutritional investigations that may be carried out concurrently with a balance study. Finally, for nitrogen balance studies, the measurement of nitrogen (eg, by the Kjeldahl technique) can be very accurate and sensitive. Despite these advantages, there are important limitations and errors that are inherent in the balance technique. The errors tend to overestimate intake and underestimate output, thereby leading to erroneously positive balances. These errors include losses of food on cooking and eating utensils and dishware, losses of feces or urine on toilet paper or in collection containers, and losses through sweat, exfoliated skin, hair and nail growth, saliva, menses, blood sampling, toothbrushing, semen, and, for nitrogen, from flatus and respiration. Cumulative balance measurements are particularly likely to be falsely positive. The magnitude of unmeasured losses vary among healthy individuals, with the magnitude of the nitrogen intake (for nitrogen), in altered environmental conditions (eg, with sweating), and possibly in disease states. Balance studies are also expensive and time consuming.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced urinary kallikrein activity in rats developing spontaneous hypertension.

Urinary kallikrein activity, intake, and excretion of sodium and water were measured in metabolic balance studies on spontaneously hypertensive rats (SHR) of the Okamoto-Aoki strain and normotensive Wistar-Kyoto rats (WKY) on a normal sodium diet from 4 through 15 wk of age. Urinary excretion of active and total kallikrein was significantly lower in SHR at all ages examined and represented a stable percentage of the values in age-matched WKY throughout development, on the average 69.5 and 67.4%, respectively. SHR exhibited a lower urinary excretion of sodium and water than WKY, a higher cumulative sodium balance at all ages studied, and a higher cumulative water balance only at ages 7 and 8 wk. The slopes of the regression lines correlating urinary kallikrein to systolic arterial pressure and to urinary excretion and cumulative balance of sodium and water were always significantly less in SHR than in WKY. The results of the present study indicate that SHR developing hypertension exhibit a precocious and stable abnormality in renal excretion of kallikrein activity.

Na+, K+, and BP homeostasis in man during furosemide: Effects of prazosin and captopril

Furosemide increases sodium (Na+) and potassium (K+) excretion but if dietary salt is provided, a compensatory reduction in Na+ and K+ excretion follows which restores neutral balances within 18 to 24 hours. This compensation is not interrupted by blockade of the renin-angiotensin-aldosterone system (RAA) alone with captopril. Since plasma norepinephrine concentration increases after furosemide and alpha 1 adrenoreceptors can mediate enhanced Na+ reabsorption, we administered prazosin (2 mg 6 hr-1) to six normal volunteers consuming a daily intake of 270 mmol of Na+ and 75 mmol of K+, and added captopril (25 mg 6 hr-1) for an additional day to block the RAA system concurrently. Furosemide (40 mg day-1) was given for the last four days. Prazosin given alone before the diuretic reduced (P less than 0.05) BP and plasma angiotensin II (AII) concentration and increased body weight and heart rate. However, when given with furosemide, neither prazosin nor prazosin with captopril modified the short-term natriuretic or kaliuretic responses to furosemide, or the ensuing compensatory reductions in Na+ and K+ excretion. Accordingly, cumulative balances for Na+ and K+ remained neutral over four days of diuretic administration. Neither drug altered the renal responsiveness to the diuretic which was assessed from the relationship between renal Na+ and K+ excretion and diuretic elimination. Although the BP was maintained when furosemide was given alone, when given with prazosin and captopril, the mean BP fell by 13 +/- 5 mm Hg (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Balance studies in patients with intestinal resection: how long is enough?

1. Results from two independent metabolic balance studies in patients with ileal resection with or without a remaining colon were examined to assess the precision of the mineral, protein and fat balances obtained. 2. Low day-to-day variation in balances was found in patients with ileostomy/jejunostomy, irrespective of formula diet composition. In contrast, patients with a remaining colon showed considerable variation, with reliable cumulative balances often not reached for many weeks. 3. In conclusion, short-term cumulative balances can be performed with good precision in patients with ileostomy or jejunostomy.

Public Policy, the Exchange Rate, and Agricultural Exports: Discussion

During the past twelve years, the volatile behavior of exchange rates has occupied the attention of economic policy makers because exchange rates directly influence such important economic phenomena as inflation, interest rates, and international competitiveness. In today's highly integrated world economic system, exchange rates are particularly important to export-oriented sectors like U.S. agriculture. In spite of the potential significance of exchange rate changes to U.S. agricultural trade, the agricultural economics profession has begun rather slowly to investigate and empirically test some basic hypotheses relating to flexible exchange rates and agricultural trade. The three papers presented in this session discuss several aspects of the exchange rateagricultural trade relationship. The Batten and Belongia paper is an empirical study of the role real exchange rates play in affecting agricultural exports and of the factors that explain real exchange rates. Their empirical analysis consists of an estimated U.S. agricultural export equation where foreign real income, U.S. real agricultural prices, and the real trade-weighted exchange rate are the explanatory variables. Next, the authors present an equation that utilizes the real interest rate differential and the cumulative current account balance as the basic determinants of the real exchange rate of the dollar.