Biochemistry: Minerals and Gastric Juice

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Questions and Answers

What is the expected outcome when sulphur flower is added to a solution containing bile salts?

The sulphur flower changes color.

The sulphur flower dissolves completely in the solution.

The sulphur flower remains at the liquid surface.

The sulphur flower sinks to the bottom of the test tube. (correct)

What condition is characterized by a decrease in hydrochloric acid secretion and an increase in lactic acid in gastric juice?

Hyperacidity

Normal acidity

Alkalosis

Hypo/anacidity (correct)

Which chemical reaction indicates the presence of lactic acid when using Berg reactive?

The solution remains colorless.

The solution becomes viscous.

The solution turns yellow in color. (correct)

The formation of a blue precipitate.

What color change is observed in the Uffalman reaction when lactic acid is present?

From violet to yellow. Signup and view all the answers

What is the role of intestinal bacterial flora in pathologies associated with hypo/anacidity?

They convert glucose from food into lactic acid. Signup and view all the answers

What color precipitate appears when FeCl3 is added to saliva in the presence of HCl?

Brick-red Signup and view all the answers

Which substance's concentration increases in the saliva of smokers compared to non-smokers?

SCN- Signup and view all the answers

What is the role of histamine in gastric secretion tests?

Stimulates HCl secretion Signup and view all the answers

What is the standard dose of histamine administered during the augmented histamine test?

40 µg/kg Signup and view all the answers

Which method is commonly used in humans to collect gastric juice?

Einthorn tube or endoscope Signup and view all the answers

What happens to the HCl secretion rate when histamine is administered to patients with atrophic gastritis?

It stays unchanged Signup and view all the answers

Why should antiacid and anticholinergic therapy be removed 24 hours before the gastric acid stimulation test?

To prevent interference with HCl secretion Signup and view all the answers

How is the gastric secretion measured during the augmented histamine test?

From samples collected every 15 minutes Signup and view all the answers

What is the primary effect observed following histamine administration within the first post-injection hour?

Peak secretory effect Signup and view all the answers

Which of the following statements is true regarding the Histalog test?

Adverse events are rare. Signup and view all the answers

What is the basis of the insulin test in the context of gastric secretion?

It induces hypoglycemia to stimulate gastric secretion. Signup and view all the answers

How does the gastric secretory response to ethanol and caffeine compare to that of histamine and pentagastrin?

It is negligible compared to histamine and pentagastrin. Signup and view all the answers

What volume and maximal acid flow are associated with a normal gastric acid secretion?

50 ml, 20 + 4 mEq/hour Signup and view all the answers

Which of the following materials is NOT used in the titrimetric method for measuring gastric juice acidity?

HCl solution Signup and view all the answers

What color change indicates a pH shift using Topffer reactive in the titrimetric method?

Yellow-orange to colorless Signup and view all the answers

What is the safe stimulant of gastric acid secretion approved in 1967?

Pentagastrin Signup and view all the answers

What is indicated by a red color when adding Topffer reactive to gastric juice?

Presence of free HCl Signup and view all the answers

What is the purpose of adding phenolphthalein during titration?

To signal the neutralization of combined HCl Signup and view all the answers

How is the total acidity calculated according to Javorski's method?

(N1 + N2) x 0.00365 x 100 Signup and view all the answers

Which method uses evaporation and the fluoroglucin solution to detect free HCl?

Gastric juice evaporation Signup and view all the answers

What is the normal value for total acidity in gastric juice in mEq/l?

100-120 mEq/l Signup and view all the answers

What does the presence of bile salts do during emulsification?

Reduces superficial tension Signup and view all the answers

What is the equivalent weight of HCl used for calculations?

36.5 g Signup and view all the answers

What color change signifies the end of titration with NaOH for free HCl?

Pink Signup and view all the answers

Study Notes

Minerals Evidence in Saliva

Materials: Test tube, FeCl₃ (ferric chloride) 3%, HCl (hydrochloric acid) 10%, saliva
Procedure: Add 3-4 ml of saliva to a test tube. Add 1-2 drops of HCl and 1-2 drops of FeCl₃. A brick-red precipitate of ferric sulfocyanate indicates presence of thiocyanate ions (SCN⁻).
SCN Ion Concentration: 0.01-0.03 mg%. An excretory product from protein metabolism or fruit.
Mechanism: Detoxification. The concentration increases in smokers' saliva.
Smokers vs. Non-Smokers: Smokers' saliva shows a darker, more intense color due to increased KSCN concentration.

Gastric Juice Collection

Method: Endoscopic or Einthorn tube aspiration.
Stimulation: Clinical stimulation possible with histamine, histalog, pentagastrin, or insulin.
Procedure (Maximal Stimulatory Test using Histamine):
- 24 hours before test, stop anti-acid and anti-cholinergic therapy.
- Pass Einthorn tube to stomach in the morning.
- Collect basal secretion for 1 hour.
- Administer histamine phosphate (0.04 mg/kg body weight).
- Collect samples every 15 minutes for an hour.
- Measure HCl concentration in each sample.

HCl Acid Dosage in Gastric Juice

Principle: Titrimetric method to neutralize gastric juice acidity using NaOH.
Materials: NaOH (n/10), Topffer reactive (indicator), phenolphthalein, glass ware, (Erlenmeyer flasks, pipettes, burettes, test tubes).
Procedure:
- Add 10 ml of gastric juice to an Erlenmeyer flask.
- Add 3-4 drops of the Topffer reactive indicator.
- Titrate with NaOH n/10 until the solution turns yellow-orange, noting the volume used for "free HCl".
- Add 2 drops of phenolphthalein. Continue titration for "combined HCl".
Calculation: Results expressed in clinical units, or grams of HCl per 100 or 1000 ml of gastric juice. Formulas provided for calculating.

Normal Values of Gastric Juice Acidity

Free HCl: 15 C.U. (clinical units) or 1 g%
Combined HCl: 25 C.U. or ~1.25- 2.5 g%
Total HCl: 40 C.U. or ~2.5- 3.5 g%
Calculations in mEq/L: Formulas are provided for converting C.U. values to mEq/L for each component.

The Evidence of Free HCl Acid in Gastric Juice

Principle: Heat gastric juice with Gunsburg reactive.
Materials: Porcelain capsule, filtered gastric juice, gas burner, Gunsburg reactive (alcoholic solution of vanillin and fluroglucin).
Procedure: Add drops of gastric juice to a heated capsule and Gunsburg reactive. A red colour indicates free HCl.

Hay Reaction

Principle: Bile salts reduce surface tension between water and fats (emulsification).
Materials: Test tubes, oil, different concentrations of bile salts solutions, and sulfur powder.
Procedure: Add bile salts solution to one tube and water to another. Add sulfur powder to each tube. Observation of whether sulfur powder sinks to the bottom or remains on the surface indicates presence/absence of bile salts.

The Berg Reaction

Principle: Lactic acid is not normally present in gastric juice, but can appear in pathological conditions (like hypo or anacid situations where bacterial contamination produce it from glucose).
Materials: Berg reactive (FeCl3 solution 30% in acidic solution), test tubes, and gastric juice.
Procedure: Add 8-10 ml of Berg reactive to a test tube and 2 ml of gastric juice. A yellow colour indicates lactic acid.

The Uffalman Reaction

Principle: Detects lactic acid.
Materials: Uffalman reactive (FeCl3. solution in phenol), test tubes, and gastric juice.
Procedure: Add 5-6 ml of Uffalman reactive to a test tube and 1 ml of gastric juice. A yellow color indicates lactic acid.

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Description

Explore the fascinating interactions of minerals in saliva, particularly the indicators of thiocyanate ions through chemical testing. Learn the methods for gastric juice collection and stimulation, essential for understanding digestive processes and conditions. This quiz covers essential concepts related to biochemistry and human physiology.