This maneuver in studies had a sensitivity of 100% and a specificity of 80% to 88% in detecting murmurs originating in the right heart. Positive Carvallos sign describes the increase in intensity of a tricuspid regurgitation murmur heard with inspiration. Abrupt standing
Squatting, by increasing afterload and increasing preload. Squatting leads to an increase in systemic vascular resistance. An increase in systemic vascular resistance results in an increase in afterload. With HOCM, an increase in afterload will hold the obstruction in a more open configuration. This will decrease the loudness of the murmur with HOCM. Handgrip maneuver, by increasing afterload. Like squatting, this will decrease the loudness of the HOCM murmur. Valsalva maneuver. Valsalva maneuver has utility in detecting hypertrophic obstructive cardiomyopathy (HOCM). According to one study, it has a sensitivity of 65% and specificity of 96% in HOCM. Valsalva maneuver, as well as standing, decrease venous return to the heart. As a result, this decreases left ventricular filling. With HOCM, the outflow obstruction increases with a decrease in preload. This will increase the loudness of the murmur with HOCM. Post ectopic potentiation
Inhaled amyl nitrite. This is a vasodilator that diminishes systolic murmurs in left-to-right shunts in ventricular septal defects. It also reveals right-to left shunts in the setting of pulmonic stenosis and a ventricular septal defect. Methoxamine
Positioning of the patient. In the lateral decubitus position or lying on the left side. This will make murmurs in the mitral valve area more pronounced. Anatomic sources
Systolic

Aortic valve stenosis is a crescendo/decrescendo systolic murmur.
Reabsorption is a two-step process beginning with the active or passive extraction of substances from the tubule fluid into the renal interstitium (the connective tissue that surrounds the nephrons), and then the transport of these substances from the interstitium into the bloodstream. These transport processes are driven by Starling forces, diffusion, and active transport. Indirect reabsorption
In some cases, reabsorption is indirect. For example, bicarbonate (HCO3−) does not have a transporter, so its reabsorption involves a series of reactions in the tubule lumen and tubular epithelium. It begins with the active secretion of a hydrogen ion (H+) into the tubule fluid via a Na/H exchanger:

In the lumen
The H+ combines with HCO3− to form carbonic acid (H2CO3)
Luminal carbonic anhydrase enzymatically converts H2CO3 into H2O and CO2
CO2 freely diffuses into the cell
In the epithelial cell
Cytoplasmic carbonic anhydrase converts the CO2 and H2O (which is abundant in the cell) into H2CO3
H2CO3 readily dissociates into H+ and HCO3−
HCO3− is facilitated out of the cells basolateral membrane

Influence of hormones
Some key regulatory hormones for reabsorption include:

aldosterone, which stimulates active sodium reabsorption (and water as a result)
antidiuretic hormone, which stimulates passive water reabsorptionBoth hormones exert their effects principally on the collecting ducts. Tubular secretion occurs simultaneously during reabsorption of filtrate. Substances, generally produced by body or the by-products of cell metabolism that can become toxic in high concentration, and some drugs (if taken). These all are secreted into the lumen of renal tubule. Tubular secretion can be either active or passive or co-transport.