Gastric protease

The gastric juice contains PP and gastric protease, and the activity ratio of the two is 4:1, which is secreted by the main cells of the stomach, and is converted from pepsinogen (PG). PG is divided into two groups according to its electrophoretic mobility, called PGI and PGII, which can be released into the blood, and only PGI is discharged from the urine. PG is active in acidic gastric juices and inactivates at pH greater than 5. The pepsinogen secreted into the gastric cavity by the main cells of the gastric gland is inactive and is converted to an active pepsin under the action of gastric acid. Activated pepsin also activates pepsinogen. Pepsin can hydrolyze proteins, the main products are standard and sputum, a small amount of peptides and amino acids. However, pepsin must be effective in an acidic environment, and its optimum pH is 2.0. As the pH increases, its activity decreases.

Basic Information

Specialist classification: Digestive examination classification: biochemical examination

Applicable gender: whether men and women apply fasting: fasting

Tips: Avoid eating a lot of food before checking. Normal value

Metti method, PP40 ~ 60u. PGI 60.6 ± 13.9 mg / ml; PGII 11.9 ± 4.2 mg / ml, PGI / PGII ratio of 5.52 ± 1.86.

Clinical significance

1, PP is mostly normal in gastric ulcer; duodenal ulcer is significantly increased; chronic duodenitis, gastric dilatation, chronic gastritis activity is weak; malignant anemia is extremely low or inactive.

2. The elevated levels of PGI and PGII suggest an increased risk of peptic ulcer, and an increase in PGI content is meaningful for judging ulcer activity.

3, PGI / PGII ratio in gastric cancer and atrophic gastritis were significantly reduced, suggesting that this test can be used as a trace indicator of atrophic gastritis and early detection of gastric cancer.

Low results may be diseases: duodenal ulcer, chronic gastritis, acute gastric dilatation results may be high disease: malignant tumor caused by anemia considerations

Taboo before inspection: Eat a lot of food, affecting the inspection process.

Requirements for examination: Pepsin isoenzyme levels in the blood can more accurately reflect the gastric mucosa. The patient is instructed by the doctor to do the relevant checks.

Inspection process

Method of collecting gastric juice:

Before collecting gastric juice, fasting, banned drugs, and smoking bans for more than a few hours. In the morning, the doctor will sterilize (cooked) the stomach tube into the stomach through the nose or mouth, and reach the stomach bend at a depth of 50-55 cm. Mucus pool; then use a 50 ml syringe to the stomach tube to aspirate the gastric juice (or continue to attract with a negative pressure pump), after filling, inject into the container, and then take the tube to continue pumping; the patient can change position during the collection process , side, prone and sitting position), try to suck the liquid in the stomach as much as possible; after the tube is removed, record the amount of gastric juice extracted, and label it on the container for inspection.

Inspection operation method:

Take 6 tubes, 3 of which are precisely added to the reference solution 1ml, and the other 3 are precisely added to the test solution 1ml, placed in a 37 ° C ± 0.5 ° C water bath, kept for 5 minutes, precision preheating to 37 ° C ± 0.5 The hemoglobin test solution at °C was 5 ml, shaken, and accurately timed, and reacted in a 37 ° C ± 0.5 ° C water bath for 10 minutes. Immediately add 5 ml of 5% trichloroacetic acid solution, shake well, filter, and take the filtrate for later use. Take another tube, add 5ml of hemoglobin test solution, place it in a 37°C±0.5°C water bath for 10 minutes, then add 5ml of 5% trichloroacetic acid solution, one of which is added with 1ml of test solution, and the other one Add 1 ml of the above hydrochloric acid solution, shake well, filter, and take the filtrate as the blank of the test sample and the control, respectively, and measure the absorbance at a wavelength of 275 nm by spectrophotometry (Appendix IVA) to calculate the average value AS and A, calculated by the following formula; A × Ws × n.

Per 1g of protease-containing activity (unit) = As × W × 10 × 181.19 where AS is the average absorbance of the control; A is the average absorbance of the test article; Ws is the tyrosine containing 1 ml of the reference solution. Quantity, μg; W is the sample volume of the test sample, g; n is the dilution factor of the test sample.

Under the above conditions, the amount of enzyme which hydrolyzes hemoglobin to produce 1 μmol of tyrosine per minute is a protease activity unit.

Not suitable for the crowd

Gastric perforation is prohibited in patients with gastric perforation.

Adverse reactions and risks

After the gastric juice is collected, it is not advisable to eat immediately, and rest is needed to avoid gastrointestinal discomfort such as indigestion.