Increased Glomerular Hydrostatic Pressure is Associated with Tubular Creatinine Reabsorption in Healthy Subjects

Background: Cr is secreted by the proximal tubules and thus Cr clearance (Ccr) can overestimate inulin clearance (Cin). However, in some cases, Ccr can even underestimate Cin. This suggests that Cr could be reabsorbed in the tubuli. We examined the clinical parameters that are associated with tubular Cr reabsorption. Methods: In 80 kidney donor candidates (53.9 ± 13.2 years, 29 males), Cin and para-aminohippuric acid clearance were measured simultaneously. Intrarenal hemodynamic parameters were calculated by Gomez’s formulae. To quantify the secretory component of Ccr (SFcr), it was calculated as follows: SFcr = (Ccr − Cin)/Ccr. Results: Twenty-five subjects (31.3%) showed SFcr values <0. SFcr that correlated significantly and negatively with efferent arteriolar resistance (Re) and glomerular hydrostatic pressure (Pglo) (Re: r = −0.30, p = 0.008; Pglo: r = −0.28, p = 0.025). In multiple regression analyses, Re and Pglo were significantly and negatively associated with SFcr after adjustment for other confounders. Conclusions: These findings suggest that tubular reabsorption of Cr can occur in some cases. Intrarenal glomerular hemodynamic burden may be related to tubular creatinine reabsorption, which possibly leads to lower Ccr values.

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U-shaped relationship between serum uric acid levels and intrarenal hemodynamic parameters in healthy subjects

AJP Renal Physiology ◽

10.1152/ajprenal.00645.2016 ◽

2017 ◽

Vol 312 (6) ◽

pp. F992-F997 ◽

Cited By ~ 14

Author(s):

Hideki Uedono ◽

Akihiro Tsuda ◽

Eiji Ishimura ◽

Shinya Nakatani ◽

Masafumi Kurajoh ◽

...

Keyword(s):

Uric Acid ◽

Regression Analysis ◽

Serum Uric Acid ◽

Healthy Subjects ◽

Hemodynamic Parameters ◽

Quadratic Regression ◽

Dummy Variables ◽

Arteriolar Resistance ◽

Glomerular Hemodynamics ◽

The Relationship

Hyperuricemia has been reported to affect renal hemodynamics. In a recent study, both low and high levels of serum uric acid (SUA) were found to be associated with loss of kidney function. The goal of this study was to evaluate the relationship between SUA levels and intrarenal hemodynamic parameters in healthy subjects, using plasma clearance of para-aminohippurate (CPAH) and inulin (Cin). Renal and glomerular hemodynamics were evaluated by simultaneous measurements of CPAH and Cin in 48 healthy subjects (54.6 ± 13.4 yr). Intrarenal hemodynamic parameters, including efferent and afferent (Ra) arteriolar resistance, were calculated using Gómez’s formulas. Relationships of SUA levels with these intrarenal hemodynamic parameters were examined. In quadratic regression analysis, SUA levels had a significant inverse U-shaped relationship with Cin ( P < 0.0001, R2 = 0.350) and CPAH ( P = 0.0093, R2 = 0.188) and a U-shaped relationship with Ra ( P = 0.0011, R2 = 0.262). In multiple regression analysis with normal (3.5–6.0 mg/dl) and mildly low or high (<3.5 or >6.0 mg/dl) SUA levels entered as dummy variables of zero and one, respectively, mildly low or high SUA levels were significantly and independently associated with Ra (β = 0.230, P = 0.0403) after adjustment for several factors ( R2 = 0.597, P < 0.0001). Both mild hyperuricemia and mild hypouricemia are significantly associated with increased Ra, although weakly. The increase in Ra in subjects with mild hyperuricemia or hypouricemia may be related to renal hemodynamic abnormalities, possibly leading to a decline in renal function.

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Analysis of renal denervation in the hydropenic rat: interactions with angiotensin II

AJP Renal Physiology ◽

10.1152/ajprenal.1984.246.1.f87 ◽

1984 ◽

Vol 246 (1) ◽

pp. F87-F95 ◽

Cited By ~ 2

Author(s):

J. C. Pelayo ◽

R. C. Blantz

Keyword(s):

Angiotensin Ii ◽

Hydrostatic Pressure ◽

Wistar Rats ◽

Renal Denervation ◽

Tubular Reabsorption ◽

Arteriolar Resistance ◽

Proximal Tubular ◽

Glomerular Ultrafiltration ◽

Renal Vascular ◽

Proximal Tubular Reabsorption

Nephron filtration rate (SNGFR), its determinants, and proximal tubular reabsorption were measured in hydropenic Munich-Wistar rats with sham-operated (sham) or denervated (DNx) kidneys before and during the administration of [Sar1, Ala8]angiotensin II or SQ 14225. The glomerular ultrafiltration coefficient (LpA) was significantly lower in DNx than in sham rats (P less than 0.025). However, SNGFR was not altered due to an offsetting increment in transcapillary glomerular hydrostatic pressure (delta P) in DNx (P less than 0.005). The marked increment of delta P in DNx was due to an increase in the glomerular capillary hydrostatic pressure, secondary to decreased afferent arteriolar resistance. The infusion of angiotensin II inhibitors to denervated kidneys completely normalized LpA but did not alter sham values. SQ 14225 but not [Sar1, Ala8]angiotensin II infusion provided a nephron plasma flow-dependent increase in SNGFR, secondary to a striking reduction in both glomerular vascular resistances. Endogenous angiotensin II activity may be enhanced by renal denervation, and angiotensin II acts to reduce LpA in this condition and may modulate the final level of renal vascular resistances after acute renal denervation.

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Pulse Pressure Variation Can Predict the Hemodynamic Response to Pneumoperitoneum in Dogs: A Retrospective Study

Veterinary Sciences ◽

10.3390/vetsci6010017 ◽

2019 ◽

Vol 6 (1) ◽

pp. 17

Author(s):

Caterina Di Bella ◽

Luca Lacitignola ◽

Laura Fracassi ◽

Despoina Skouropoulou ◽

Antonio Crovace ◽

...

Keyword(s):

Pulse Pressure ◽

Roc Curve ◽

Pulse Pressure Variation ◽

Healthy Subjects ◽

Hemodynamic Response ◽

Hemodynamic Parameter ◽

Pressure Variation ◽

Hemodynamic Parameters ◽

Group Data ◽

Valid Predictor

Pneumoperitoneum may induce important hemodynamic alterations in healthy subjects. Pulse pressure variation (PPV) is a hemodynamic parameter able to discriminate preload dependent subjects. Anesthesia records of dogs undergoing laparoscopy were retrospectively evaluated. The anesthetic protocol included acepromazine, methadone, propofol and isoflurane administered with oxygen under mechanical ventilation. The hemodynamic parameters were considered five minutes before (BASE) and ten minutes after (P10) the pneumoperitoneum. Based on the cardiac index (CI) variation, at P10, dogs were classified as sensitive (S group, CI ≤ 15%) and non-sensitive (NO-S group). Data were analyzed with the ANOVA test and the ROC curve (p < 0.05). Fifty-five percent of dogs (S) had a reduction of CI ≥ 15% at P10 (2.97 ± 1.4 L/min/m2) compared to BASE (4.32 ± 1.62 L/min/m2) and at P10 in the NO-S group (4.51 ± 1.41 L/min/m2). PPV at BASE was significantly higher in the S group (22.4% ± 6.1%) compared to the NO-S group (10.9% ± 3.3%). The ROC curve showed a threshold of PPV > 16% to distinguish the S and NO-S groups. PPV may be a valid predictor of the hemodynamic response to pneumoperitoneum in dogs. A PPV > 16% can identify patients that may require fluid administration before the creation of pneumoperitoneum.

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THE ACTION OF CORTICOSTEROIDS ON THE RENAL EXCRETION AND UTILIZATION OF CITRIC ACID

Acta Endocrinologica ◽

10.1530/acta.0.0460414 ◽

1964 ◽

Vol 46 (3) ◽

pp. 414-420 ◽

Cited By ~ 1

Author(s):

Helge Laake ◽

Erling Kruge Brodwall

Keyword(s):

Citric Acid ◽

Steroid Hormones ◽

Renal Excretion ◽

Anabolic Steroids ◽

Inhibitory Effect ◽

Renal Tissue ◽

Tubular Reabsorption ◽

Enzyme Systems ◽

Acid Clearance ◽

Tubular Lumen

ABSTRACT During treatment with steroid hormones the tubular reabsorption of citric acid (cit.) increases, and the endogenous citric acid clearance is reduced. This is attributed to increased diffusion of citric acid from the tubular lumen to the renal tissue. With simultaneous administration of corticosteroids and anabolic steroids the tubular reabsorption of citric acid becomes normal. Steroid hormones block the renal synthesis of cit. and the renal utilization of cit. becomes identical with the amount of cit. reabsorbed in the tubules. Blockade of the synthesis of cit. is attributed to the inhibitory effect of steroid hormones on enzyme systems.

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Elevated circulating Gpnmb levels are associated with hyperthyroidism

Endocrine Connections ◽

10.1530/ec-20-0240 ◽

2020 ◽

Vol 9 (8) ◽

pp. 783-792

Author(s):

Jiayang Lin ◽

Peizhen Zhang ◽

Yan Huang ◽

Xueyun Wei ◽

Dan Guo ◽

...

Keyword(s):

Healthy Subjects ◽

Metabolic Disorders ◽

Ldl Cholesterol ◽

Fasting Glucose ◽

Lipid Homeostasis ◽

Therapeutic Monitoring ◽

Regression Analyses ◽

Free Triiodothyronine ◽

Free T4 ◽

Hyperthyroid Patients

Background: Glycoprotein non-metastatic protein B (Gpnmb) has been identified as a new cytokine secreted by hepatocyte that plays an important role in balancing lipid homeostasis and development of obesity and metabolic disorders. However, information is not available regarding the association between circulating Gpnmb and hyperthyroid in humans. Methods: We measured serum Gpnmb in 180 hyperthyroid patients and 82 healthy subjects that were recruited from the clinic. Of them, 46 hyperthyroid patients received thionamide treatment for 3 months. Results: Hyperthyroid subjects had higher levels of circulating Gpnmb than healthy controls (47.8 ± 10.1 ng/mL vs 31.0 ± 4.9 ng/mL, P < 0.001). Subjects with higher levels of serum free triiodothyronine (T3) and free thyroxine (T4) had higher levels of circulating Gpnmb. After thionamide treatment, levels of circulating Gpnmb in hyperthyroid subjects remarkably declined with significant improvement of thyroid function (P < 0.001). Furthermore, the change of circulating Gpnmb levels was significantly associated with basal metabolic rate (BMR) and thyroid hormones, including free T3 and free T4, adjusting for age, gender, smoking and BMI before thionamide treatment. In multivariable logistic regression analyses, circulating Gpnmb was significantly associated with risks of hyperthyroidism (OR (95% CI): 1.44 (1.20–1.74), P < 0.001), adjusted for age, gender, BMI, fasting glucose, HOMA-IR, LDL-cholesterol, ALT and AST. Conclusions: These findings indicate that circulating Gpnmb concentrations are independently associated with hyperthyroid, suggesting that circulating Gpnmb may be a predictor of risk for hyperthyroidism and can be used for therapeutic monitoring.

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Handgrip exercise elevates basilic venous hemodynamic parameters in healthy subjects

International Journal of Nursing Sciences ◽

10.1016/j.ijnss.2014.10.014 ◽

2014 ◽

Vol 1 (4) ◽

pp. 389-393

Author(s):

Min Zhang ◽

Xiu-Xin Fang ◽

Ming-E. Li ◽

Chun-Hui Zheng ◽

Xi-Huan Zhou ◽

...

Keyword(s):

Healthy Subjects ◽

Hemodynamic Parameters ◽

Handgrip Exercise

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Effect of histamine and cimetidine on retinal and choroidal blood flow in humans

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00335.2005 ◽

2005 ◽

Vol 289 (5) ◽

pp. R1387-R1391 ◽

Cited By ~ 3

Author(s):

Hemma Resch ◽

Claudia Zawinka ◽

Solveig Lung ◽

Günther Weigert ◽

Leopold Schmetterer ◽

...

Keyword(s):

Blood Flow ◽

Healthy Subjects ◽

Retinal Vessel ◽

Blood Velocity ◽

Laser Doppler ◽

Hemodynamic Parameters ◽

Arterial Diameter ◽

Choroidal Blood Flow ◽

Pulsation Amplitude ◽

Venous Diameter

Intravenous administration of histamine causes an increase in choroidal blood flow and retinal vessel diameter in healthy subjects. The mechanism underlying this effect remains to be elucidated. In the present study, we hypothesized that H2 receptor blockade alters hemodynamic effects of histamine in the choroid and retina. Eighteen healthy male nonsmoking volunteers were included in this randomized, double-masked, placebo-controlled two-way crossover study. Histamine (0.32 μg·kg−1·min−1 over 30 min) was infused intravenously in the absence (NaCl as placebo) or presence of the H2 blocker cimetidine (2.3 mg/min over 50 min). Ocular hemodynamic parameters, blood pressure, and intraocular pressure were measured before drug administration, after infusion of cimetidine or placebo, and after coinfusion of histamine. Subfoveal choroidal blood flow and fundus pulsation amplitude were measured with laser-Doppler flowmetry and laser interferometry, respectively. Retinal arterial and venous diameters were measured with a retinal vessel analyzer. Retinal blood velocity was assessed with bidirectional laser-Doppler velocimetry. Histamine increased subfoveal choroidal blood flow (+14 ± 15%, P < 0.001), fundus pulsation amplitude (+11 ± 5%, P < 0.001), retinal venous diameter (+3.0 ± 3.6%, P = 0.002), and retinal arterial diameter (+2.8 ± 4.2%, P < 0.01) but did not change retinal blood velocity. The H2 antagonist cimetidine had no significant effect on ocular hemodynamic parameters. In addition, cimetidine did not modify effects of histamine on choroidal blood flow, fundus pulsation amplitude, retinal venous diameter, and retinal arterial diameter compared with placebo. The present data confirm that histamine increases choroidal blood flow and retinal vessel diameters in healthy subjects. This ocular vasodilator effect of histamine is, however, not altered by administration of an H2 blocker. Whether the increase in blood flow is mediated via H1 receptors or other hitherto unidentified mechanisms remains to be elucidated.

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A Sex-Specific Switch in Platelet Receptor Signaling Following Myocardial Infarction

10.1101/580415 ◽

2019 ◽

Author(s):

Beom Soo Kim ◽

David A. Auerbach ◽

Hamza Sadhra ◽

Frederick S. Ling ◽

Sandra Toth ◽

...

Keyword(s):

Myocardial Infarction ◽

Platelet Activation ◽

Healthy Subjects ◽

Multivariate Regression ◽

Regression Analyses ◽

Men And Women ◽

St Segment Elevation ◽

Segment Elevation Myocardial Infarction ◽

St Segment ◽

Platelet Receptor

ABSTRACTBACKGROUNDA Sex-specific, personalized approach to anti-platelet therapy may be important in patients with myocardial infarction (MI).OBJECTIVESOur goal was to determine whether platelets activate differently in healthy men and women compared to following MI.METHODSBlood was obtained from healthy subjects or patients presenting acutely with ST-segment Elevation Myocardial Infarction (STEMI) and non-ST Segment Elevation Myocardial Infarction (NSTEMI). Platelet function through surface receptor activation was examined in healthy subjects, in patients with MI, and in age- and strain-matched mice before and after MI. Multivariate regression analyses revealed clinical variables associated with platelet receptor sensitivity at the time of MI.RESULTSPlatelets from healthy women are dose-dependently more active compared to men, particularly through the platelet thromboxane signaling pathway (7.8-fold increase in women vs. 3.0-fold in men, P=0.02). At the time of MI, platelet activation through surface protease-activated receptor 1 (PAR1) was less in women than men (3.5-fold vs. 8.5-fold, respectively, P=0.0001). Multivariate regression analyses revealed male sex (P=0.04) and NSTEMI (P=0.003) as independent predictors of enhanced platelet PAR1 signaling at the time of MI. Similar to humans, healthy female mice showed preferential thrombin-mediated platelet activation compared to male mice (8.7-fold vs. 4.8-fold, respectively; P<0.001). In the immediate post-MI environment, male mice showed preferential thrombin-mediated platelet activation compared to female mice (12.4-fold vs. 5.5-fold, respectively; P<0.001).CONCLUSIONSThese results outline a previously unrecognized sex-dependent platelet phenotype where inhibition of thrombin signaling in the peri-MI environment—particularly in males—may be an important consideration.CONDENSED ABSTRACTPreclinical studies evaluating anti-platelet drugs are generally conducted in platelets isolated from healthy individuals. Growing evidence suggests changes in platelet signaling properties in certain disease conditions compared to healthy platelets may alter the response to anti-platelet medications. This investigation revealed that platelets from men and women who are healthy and following MI signal differently, particularly through thromboxane and PAR1 receptors. This effect was especially noted in patients with NSTEMI compared to STEMI. These observations raise the possibility of considering a sex-specific anti-platelet regimen for males and females in atheroembolic vascular diseases such as NSTEMI.

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Effects of diaphragmatic contraction on lower limb venous return and central hemodynamic parameters contrasting healthy subjects versus heart failure patients at rest and during exercise

Physiological Reports ◽

10.14814/phy2.12216 ◽

2014 ◽

Vol 2 (12) ◽

pp. e12216 ◽

Cited By ~ 4

Author(s):

Fernanda Machado Balzan ◽

Régis Chiarelli da Silva ◽

Danton Pereira da Silva ◽

Paulo Roberto Stefani Sanches ◽

Angela Maria Vicente Tavares ◽

...

Keyword(s):

Heart Failure ◽

Lower Limb ◽

Healthy Subjects ◽

Venous Return ◽

Hemodynamic Parameters ◽

Heart Failure Patients ◽

Central Hemodynamic

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Face Perception and Pareidolia Production in Patients With Parkinson's Disease

Frontiers in Neurology ◽

10.3389/fneur.2021.669691 ◽

2021 ◽

Vol 12 ◽

Author(s):

Nicole Göbel ◽

Jens Carsten Möller ◽

Nathalie Hollenstein ◽

Andreas Binder ◽

Matthias Oechsner ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Face Perception ◽

Cognitive Assessment ◽

Healthy Subjects ◽

Regression Analyses ◽

Relevant Stimulus ◽

Attention Networks ◽

Correct Location ◽

Non Motor Symptoms

In Parkinson's disease (PD) patients, visual misperceptions are a major problem within the non-motor symptoms. Pareidolia, i.e., the tendency to perceive a specific, meaningful image in an ambiguous visual pattern, is a phenomenon that occurs also in healthy subjects. Literature suggests that the perception of face pareidolia may be increased in patients with neurodegenerative diseases. We aimed to examine, within the same experiment, face perception and the production of face pareidolia in PD patients and healthy controls (HC). Thirty participants (15 PD patients and 15 HC) were presented with 47 naturalistic photographs in which faces were embedded or not. The likelihood to perceive the embedded faces was modified by manipulating their transparency. Participants were asked to decide for each photograph whether a face was embedded or not. We found that PD patients were significantly less likely to recognize embedded faces than controls. However, PD patients also perceived faces significantly more often in locations where none were actually present than controls. Linear regression analyses showed that gender, age, hallucinations, and Multiple-Choice Vocabulary Intelligence Test (MWT) score were significant predictors of face pareidolia production in PD patients. Montreal Cognitive Assessment (MoCA) was a significant predictor for pareidolia production in PD patients in trials in which a face was embedded in another region [F(1, 13) = 24.4, p = <0.001]. We conclude that our new embedded faces paradigm is a useful tool to distinguish face perception performance between HC and PD patients. Furthermore, we speculate that our results observed in PD patients rely on disturbed interactions between the Dorsal (DAN) and Ventral Attention Networks (VAN). In photographs in which a face is present, the VAN may detect this as a behaviourally relevant stimulus. However, due to the deficient communication with the DAN in PD patients, the DAN would not direct attention to the correct location, identifying a face at a location where actually none is present.

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