Abstract 360: Increased Aldosterone Sensitivity in Young Blacks

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Wanzhu Tu ◽  
Hai Liu ◽  
George Eckert ◽  
J Howard Pratt
Keyword(s):  
Volume Expansion ◽  
Distal Tubule ◽  
Plasma Renin ◽  
Sodium Reabsorption ◽  
Sodium Retention ◽  
Lower Plasma ◽  
Blacks And Whites ◽  
Small Increments ◽  
Using Data ◽  
Different Levels

Aldosterone contributes to the elevation of blood pressure (BP) by acting on the distal tubule to cause greater sodium retention and volume expansion. Blacks, in comparison with whites, have lower plasma aldosterone concentrations (PAC), possibly due to increased sodium reabsorption and resultant renin suppression, as evidenced by their lower plasma renin activity (PRA); but BP is on average higher in blacks. The seemingly different BP-PAC relationships in blacks and whites raise point to the possibility of different aldosterone sensitivity in the two race groups. Using data from a cohort of normotensive youths (n=654 observations contributed by 537 subjects), we used a varying coefficient model to examine the BP effect of PAC at different levels of PRA in blacks and whites. We characterized the effects of PAC as a function of PRA and assessed its effect on age, sex, and height-adjusted BP percentile. The estimated effects are presented graphically (Figure 1 a&b). Blacks had lower PRA and PAC (PRA: 2.8 vs 3.3, p=0.002; PAC: 8.7 vs 14.1, p<0.0001; PAC/PRA: 4.7 vs 5.4, p=0.172), and marginally higher systolic and diastolic BP percentiles (SBP%: 44.5 vs 40.6, p=0.082; DBP%: 57 vs 51, p=0.004). In blacks, the BP effect of PAC was much greater in blacks at lower PRA levels (p=0.004); in whites, PAC effect on BP was not significant (p=0.164) and the effect did not change noticeably with PRA. In conclusion, the finding supports the notion that blacks have higher levels of aldosterone sensitivity, especially for those with lower PRA. A sustained state of volume expansion appears to make blacks vulnerable to the BP effects of even small increments in sodium retention produced by aldosterone.

Studies on Mineralocorticoid ‘Escape’ in Cirrhosis

1979 ◽  
Vol 56 (5) ◽  
pp. 401-406 ◽  
Author(s):  
S. P. Wilkinson ◽  
I. K. Smith ◽  
Helen Moodie ◽  
Lucilla Poston ◽  
R. Williams
Keyword(s):  
Extracellular Fluid ◽  
Plasma Renin ◽  
Fluid Volume ◽  
The Other ◽  
Extracellular Fluid Volume ◽  
Sodium Reabsorption ◽  
Sodium Retention ◽  
Similar Extent ◽  
Water Diuresis ◽  
Diluting Segment

1. The mineralocorticoid 9α-fluorohydrocortisone was given to 12 patients with cirrhosis without ascites. In seven an ‘escape’ from its sodium-retaining effects was observed, the other five continuing to retain sodium. 2. Changes in plasma renin activity (PRA) and inulin clearance (Cinulin) were used in the assessment of possible changes in the ‘effective’ extracellular fluid volume. PRA fell and Cinulin increased to a similar extent in each of the two groups of patients. These findings do not support the concept that the failure to show the mineralocorticoid escape in some patients with cirrhosis is due to a failure of expansion of the effective extracellular fluid volume. 3. Sodium reabsorption in the different segments of the nephron as estimated by clearance techniques under conditions of maximal water diuresis showed that the greatest changes to account for both mineralocorticoid escape and sodium retention were in the part of the nephron beyond the diluting segment.

Localization of the nephron sites responsible for mineralocorticoid escape in rats

1980 ◽  
Vol 239 (2) ◽  
pp. F149-F153 ◽  
Author(s):  
D. E. Kohan ◽  
F. G. Knox
Keyword(s):  
Volume Expansion ◽  
Distal Tubule ◽  
Sodium Reabsorption ◽  
Loop Of Henle ◽  
Deoxycorticosterone Acetate ◽  
Collecting Tubule ◽  
Pars Recta ◽  
Distal Tubules ◽  
Cortical Collecting Tubule

Fractional delivery of sodium (FDNA) from the superficial late distal tubule is increased in deoxycorticosterone acetate-(DOCA) treated rats, which may compensate for a presumed mineralocorticoid-stimulated sodium reabsorption in the cortical collecting tubule. In the present study, late proximal (LPT) and early distal tubules (EDT) were micropunctured during volume expansion in control and DOCA-treated rats. Whereas FDNa to the LPT was similar in the two groups, FDNa to the EDT was greater in DOCA-treated than in control rats. Additionally, LPT and deep loop of Henle (LH) were micropunctured in volume-expanded control and DOCA-treated rats. FDNa to the bend of the LH was increased in DOCA-treated rats compared to controls. These findings indicate that in DOCA escape sodium reabsorption is diminished in the pars recta and/or loop of Henle of superficial nephrons and there is increased delivery to the bend of the loop of deep nephrons. We conclude that mineralocorticoid escape is most likely due to increased sodium delivery to the cortical collecting tubule from both deep and superficial nephrons.

Effect of adrenal enucleation on sodium excretion in the rat

1976 ◽  
Vol 231 (5) ◽  
pp. 1421-1428 ◽  
Author(s):  
EA Alexander ◽  
HH Bengele ◽  
ER McNamara
Keyword(s):  
Sodium Excretion ◽  
Filtration Rate ◽  
Adrenal Glands ◽  
Collecting Duct ◽  
Distal Tubule ◽  
Sodium Reabsorption ◽  
Sodium Retention ◽  
Hormone Production ◽  
Adrenal Hormone ◽  
Filtered Load

After the adrenal glands are removed without their capsules, so-called adrenal enucleation, rats initially retain sodium, and, after adrenal regeneration, escape from salt retention. To define the renal mechanisms involved in this alteration in salt handling, we have utilized clearance and micropuncture techniques in three groups of saline-expanded rats that were sham-operated (S), enucleated (AE), or escaped after adrenal regeneration (E.) Sodium excretion was clearly blunted after AE, 5.5 mueq/min vs. 20.5 for S and 18.7 for E. Although glomerular filtration rate (GFR) and filtered load of sodium were lower in AE rats, the delivered load of sodium beyond the late distal tubule was not different among the groups: 0.30 neq/min for AE, 0.42 for S, and 0.40 for E. This was a consequence of strikingly greater sodium reabsorption in the loop of Henle and distal tubule in both the S and E rats. In the collecting duct over 50% of the delivered sodium was reabsorbed by the AE rats while over 30% of the excreted sodium was added in this tubular segment in the other groups. These data demonstrate that the impaired natriuresis after adrenal enucleation appears to be due to striking differences in collecting duct function. Since adrenal regeneration in the escape animals reverses this sodium retention, the effect is probably related to some alteration in adrenal hormone production. Sodium excretion in markedly expanded normal rats also appears to be determined by the net addition of sodium in the collecting duct.

Distal tubular function in superficial rat tubules during volume expansion

1980 ◽  
Vol 239 (3) ◽  
pp. F228-F232 ◽  
Author(s):  
J. Diezi ◽  
M. Nenniger ◽  
G. Giebisch
Keyword(s):  
Sodium Excretion ◽  
Volume Expansion ◽  
Extracellular Volume ◽  
Distal Tubule ◽  
Urinary Sodium Excretion ◽  
Renal Perfusion ◽  
Sodium Reabsorption ◽  
Fluid Delivery ◽  
Distal Tubules ◽  
Extracellular Volume Expansion

Free-flow micropuncture experiments were carried out on superficial late proximal and distal tubules during hydropenic conditions and during extracellular volume expansion. Fluid collected from tubules was analyzed for inulin and sodium. During volume expansion, renal perfusion pressure to one kidney was reduced so that the increase in distal sodium and fluid delivery that normally occurs after saline loading was prevented. Although urinary sodium excretion remained significantly elevated in such kidneys, the rate of sodium reabsorption along the distal tubules was not different from that occurring under nondiuretic conditions. It is concluded that those factors that reduce net sodium transport in the proximal tubule during extracellular volume expansion do not act on superficial distal tubules. Additional factors beyond the distal tubule contribute to increased sodium excretion and can be shown to be activated even when delivery of fluid and sodium out of superficial distal tubules is normal.

scholarly journals Adenosine and renal sodium handling: direct natriuresis and renal nerve-mediated antinatriuresis.

1995 ◽  
Vol 6 (5) ◽  
pp. 1491-1497
Author(s):  
R Fransen ◽  
H A Koomans
Keyword(s):  
Blood Pressure ◽  
Sodium Excretion ◽  
Distal Tubule ◽  
Systemic Circulation ◽  
Renal Nerves ◽  
Sodium Reabsorption ◽  
Left Renal Artery ◽  
Sodium Retention ◽  
Renal Nerve ◽  
Sodium Handling

Adenosine infusion is associated with natriuresis as well as antinatriuresis. The physiologic significance of these opposite effects is unknown but may have to do with different conditions of ischemia, in which adenosine accumulates. These effects were characterized in the rat. First, intrarenal and systemic infusions within one animal were performed. Infusing 10 micrograms/min into the left renal artery increased sodium by approximately 50%; however, the subsequent infusion of 50 micrograms/min into the thoracic aorta decreased sodium excretion by approximately 60%, in association with a small reduction of blood pressure. Second, to explore the effect of intrarenal adenosine in tubular sodium handling, free-flow micropuncture experiments were performed. The intrarenal infusion of 10 micrograms/min again caused sodium excretion, but no change in GFR, volume, and sodium deliveries up to the early distal tubule was found. Apparently, the direct effect of adenosine in the kidney is sodium excretion, by a tubular action beyond the early distal tubule. Third, to further characterize the indirect effect, which apparently is sodium retention, adenosine was infused systemically at low rates, in order to avoid a decrease in blood pressure. A 25 micrograms/min infusion again caused sodium retention, in the absence of a fall in blood pressure. After acute left renal denervation, the antinatriuretic effect disappeared in the denervated kidney but remained in the right kidney. These data suggest that increased intrarenal adenosine suppresses sodium reabsorption at some distal nephron site, appropriately decreasing the workload of the kidney. On the other hand, systemic adenosine stimulates sodium reabsorption, an effect that is appropriate to improve systemic circulation and depends on the renal nerves.

Segmental analysis of sodium reabsorption during renal vein constriction

1982 ◽  
Vol 243 (1) ◽  
pp. F19-F22 ◽  
Author(s):  
J. C. Burnett ◽  
J. A. Haas ◽  
F. G. Knox
Keyword(s):  
Proximal Tubule ◽  
Renal Vein ◽  
Volume Expansion ◽  
Distal Tubule ◽  
Sodium Reabsorption ◽  
Loop Of Henle ◽  
Segmental Analysis ◽  
Presence And Absence

Clearance and micropuncture studies were performed in rats to identify the nephron site(s) of altered sodium reabsorption during partial renal vein constriction in the presence and absence of volume expansion. Renal vein constriction increased fractional deliver of sodium to the late proximal tubule from 52 +/- 3 to 61 +/- 4% in euvolemia and from 59 +/- 3 to 65 +/- 3% in volume expansion. In euvolemia, fractional delivery of sodium to the early distal tubule was 13 +/- 3% before and 24 +/- 6% after renal vein constriction. In volume expansion, fractional delivery of sodium to the early distal tubule decreased from 15 +/- 3 to 9 +/- 2% in response to renal vein constriction. We conclude that renal vein constriction decreases sodium reabsorption by the proximal tubule both in euvolemia and in volume expansion but that it increases sodium reabsorption by the superficial loop of Henle only in the presence of volume expansion.

Role of insulin and atrial natriuretic peptide in sodium retention in insulin-treated IDDM patients during isotonic volume expansion

Diabetes ◽  
1990 ◽  
Vol 39 (3) ◽  
pp. 289-298 ◽  
Author(s):  
R. Trevisan ◽  
P. Fioretto ◽  
A. Semplicini ◽  
G. Opocher ◽  
F. Mantero ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Volume Expansion ◽  
Sodium Retention ◽  
Atrial Natriuretic

Organizing and Managing Data Analytics Teams for Procurement

2020 ◽  
Author(s):  
Benjamin Shao ◽  
Robert D. St. Louis
Keyword(s):  
Best Practices ◽  
Business Strategy ◽  
Data Analytics ◽  
Team Members ◽  
Procurement Process ◽  
Using Data ◽  
And Training ◽  
Different Levels ◽  
The Way

Many companies are forming data analytics teams to put data to work. To enhance procurement practices, chief procurement officers (CPOs) must work effectively with data analytics teams, from hiring and training to managing and utilizing team members. This chapter presents the findings of a study on how CPOs use data analytics teams to support the procurement process. Surveys and interviews indicate companies are exhibiting different levels of maturity in using data analytics, but both the goal of CPOs (i.e., improving performance to support the business strategy) and the way to interact with data analytics teams for achieving that goal are common across companies. However, as data become more reliably available and technologies become more intelligently embedded, the best practices of organizing and managing data analytics teams for procurement will need to be constantly updated.

scholarly journals Integration of various scales for measurement of insomnia

2021 ◽  
pp. 263208432110100
Author(s):  
Satyendra Nath Chakrabartty
Keyword(s):  
Test Scores ◽  
Data Driven ◽  
Weighted Sum ◽  
Future Studies ◽  
Normal Probability ◽  
Equivalent Test ◽  
Item Scores ◽  
Using Data ◽  
Set Up ◽  
Different Levels

Background Scales for evaluating insomnia differ in number of items, response format, and result in different scores distributions and score ranges and may not facilitate meaningful comparisons. Objectives Transform ordinal item-scores of three scales of insomnia to continuous, equidistant, monotonic, normally distributed scores, avoiding limitations of summative scoring of Likert scales. Methods Equidistant item-scores by weighted sum using data-driven weights to different levels of different items, considering cell frequencies of Item-Levels matrix, followed by normalization and conversion to [1, 10]. Equivalent test-scores (as sum of transformed item- scores) for a pair of scales were found by Normal Probability curves. Empirical illustration given. Results Transformed test-scores are continuous, monotonic and followed Normal distribution with no outliers and tied scores. Such test-scores facilitate ranking, better classification and meaningful comparison of scales of different lengths and formats and finding equivalent score combinations of two scales. For a given value of transformed test-score of a scale, easy alternate method avoiding integration proposed to find equivalent scores of another scales. Equivalent scores of scales help to relate various cut-off scores of different scales and uniformity in interpretations. Integration of various scales of insomnia is achieved by finding one-to-one correspondence among the equivalent score of various scales with correlation over 0.99 Conclusion Resultant test-scores facilitated undertaking analysis in parametric set up. Considering the theoretical advantages including meaningfulness of operations, better comparison, use of such method of transforming scores of Likert items/test is recommended test and items, Future studies were suggested.

Renal blood flow, early distal sodium, and plasma renin concentrations during osmotic diuresis

2000 ◽  
Vol 279 (4) ◽  
pp. R1268-R1276 ◽  
Author(s):  
Paul P. Leyssac ◽  
Niels-Henrik Holstein-Rathlou ◽  
Ole Skøtt
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Plasma Renin ◽  
Urine Flow ◽  
Sodium Reabsorption ◽  
Osmotic Diuresis ◽  
Nacl Concentration ◽  
Proximal Tubular ◽  
Distal Tubules

Inconsistencies in previous reports regarding changes in early distal NaCl concentration (EDNaCl) and renin secretion during osmotic diuresis motivated our reinvestigation. After intravenous infusion of 10% mannitol, EDNaCl fell from 42.6 to 34.2 mM. Proximal tubular pressure increased by 12.6 mmHg. Urine flow increased 10-fold, and sodium excretion increased by 177%. Plasma renin concentration (PRC) increased by 58%. Renal blood flow and glomerular filtration rate decreased, however end-proximal flow remained unchanged. After a similar volume of hypotonic glucose (152 mM), EDNaClincreased by 3.6 mM, ( P < 0.01) without changes in renal hemodynamics, urine flow, sodium excretion rate, or PRC. Infusion of 300 μmol NaCl in a smaller volume caused EDNaCl to increase by 6.4 mM without significant changes in PRC. Urine flow and sodium excretion increased significantly. There was a significant inverse relationship between superficial nephron EDNaCl and PRC. We conclude that EDNa decreases during osmotic diuresis, suggesting that the increase in PRC was mediated by the macula densa. The results suggest that the natriuresis during osmotic diuresis is a result of impaired sodium reabsorption in distal tubules and collecting ducts.

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