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Titration of a Polyprotic Acid02:08

Titration of a Polyprotic Acid

A polyprotic acid contains more than one ionizable hydrogen and undergoes a stepwise ionization process. If the acid dissociation constants of the ionizable protons differ sufficiently from each other, then the titration curve for such polyprotic acid generates a distinct equivalence point for each of its ionizable hydrogens. Therefore, titration of a diprotic acid results in the formation of two equivalence points, whereas the titration of a triprotic acid results in the formation of three...
Titration of Polyprotic Acids with a Strong Base01:23

Titration of Polyprotic Acids with a Strong Base

Titration of a polyprotic acid, which contains multiple ionizable protons, involves distinct dissociation steps, each with its own dissociation constant (Ka). Each successive Ka is weaker than the previous one. In the titration of a polyprotic acid like sulfurous acid with a strong base such as sodium hydroxide, the base first neutralizes the initial ionizable proton, forming an intermediate species (e.g., hydrogen sulfite ions). This step's titration curve resembles that of a weak monoprotic...
Acute Pyelonephritis I: Introduction01:27

Acute Pyelonephritis I: Introduction

Pyelonephritis is a bacterial infection that primarily affects the renal parenchyma and collecting system, including the renal pelvis, tubules, and interstitial tissue of one or both kidneys. It can be classified as either acute—a sudden, severe infection—or chronic, which refers to long-term or recurrent kidney infections.The primary cause of acute pyelonephritis (APN) is bacterial infection, with Escherichia coli accounting for approximately 70-80% of cases. Other bacteria, such as Proteus,...
Titration of a Weak Acid with a Weak Base01:08

Titration of a Weak Acid with a Weak Base

Weak acids and bases do not undergo dissociation completely, and titrations between these two are rarely studied. When such studies are performed, say, for the titration of a weak acid with a weak base, the titration curve plots the change in pH as a function of the volume of base added. Take the titration of acetic acid with ammonia, for instance. During the titration, these two species form ammonium acetate and water, but the pH change is slow and gradual.
As a result, there is no simple...
Renal Regulation of Acid-Base Balance01:29

Renal Regulation of Acid-Base Balance

Metabolic reactions in the body produce nonvolatile acids, such as sulfuric acid, which generate an acid load of approximately 1 mEq of H+ per kilogram of body weight daily. Excreting H+ in the urine is essential to balance this acid load.
In the kidneys, cells within the proximal convoluted tubules (PCT) and the collecting ducts secrete hydrogen ions (H+) into the tubular fluid. Specifically, in the PCT, Na+/H+ antiporters secrete H+ while reabsorbing Na+.
However, the intercalated cells in...
Titration of Polyprotic Base with a Strong Acid01:18

Titration of Polyprotic Base with a Strong Acid

The titration of a polyprotic base such as sodium carbonate with a strong acid such as hydrochloric acid results in two equivalence points on the titration curve. At the first equivalence point, the carbonate ions in the base are completely converted to bicarbonate ions. The second equivalence point corresponds to the complete conversion of bicarbonate ions to carbonic acid, which dissociates into carbon dioxide and water. The region before the first equivalence point corresponds to the...

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Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method
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Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

Published on: May 18, 2018

Alkaptonuria.

Molly Yancovitz1, Robert Anolik, Miriam Keltz Pomeranz

  • 1Department of Dermatology, New York University, New York, NY, USA.

Dermatology Online Journal
|December 18, 2010
PubMed
Summary
This summary is machine-generated.

Alkaptonuria is a rare genetic disorder causing joint pain and blue-grey pigmentation due to homogentisic acid buildup. Ongoing trials explore nitisinone as a potential treatment for this condition.

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Area of Science:

  • Medical Genetics
  • Metabolic Disorders
  • Rheumatology

Background:

  • Alkaptonuria (AKU) is an autosomal recessive metabolic disorder.
  • It stems from a deficiency in the enzyme homogentisic acid oxidase.
  • This deficiency leads to the accumulation of homogentisic acid (HGA) in various tissues.

Observation:

  • A 69-year-old woman presented with a 30-year history of chronic lower back and large joint pain (hips, shoulders).
  • Clinical examination revealed blue-grey pigmented macules on the ear cartilage and sclera.
  • The patient had a history of aortic stenosis.

Findings:

  • Elevated urine homogentisic acid levels confirmed the diagnosis of alkaptonuria.
  • The disease manifests as blue-grey pigmentation in cartilage, sclerae, face, and hands.
  • Severe arthropathy and cardiac valve disease are characteristic complications.

Implications:

  • Current treatment options for alkaptonuria are limited.
  • Nitisinone shows promise as a therapeutic agent, with ongoing clinical trials.
  • Early intervention and management of complications are crucial for patients with AKU.