Histosonda®

INTRODUCTION

Gastrin is a peptide fundamentally produced by neuroendocrine cells known as G cells situated in the bottom of the gastric antrum crypts.  The principle mission of these cells is to stimulate the secretion of hydrogen chloride in the mucosal parietal cells of the gastric body.

There are G cell tumors which exist in the pancreas and duodenum even though these cells are not normally found in either of these organs.

Tumors that secrete gastrin are known as gastrinomas and more than 50% of these are malignant.  These tumors can be associated with Zollinger-Ellison syndrome.

Duodenal gastrinomas are frequently associated with MEN1 syndrome and are usually of a small size.  They are generally unapparent although they metastasize early in the lymph node regions and the metastasis is usually a larger size than that of the tumor of origin.

The pancreatic gastrinomas are less frequently associated with MEN 1 and they metastasize principally in the liver.

The regulation of hydrochloric acid secretion in the stomach is maintained by a feedback response related to gastrin.  For this reason hypergastrinemia and hyperplasia of the G cells is frequently observed in patients with fundamentally autoimmune-type atrophic gastritis.

INTENDED USE

For use in In Vitro Diagnosis.

The Kit Histosonda Gastrin is useful for the diagnosis of neuroendocrine tumors producing gastrin and validation of G cell hyperplasias in the stomach.

WARNINGS AND PRECAUTIONS

The Kit Histosonda Gastrin has been designed for professional use in In Vitro Diagnosis and must be manipulated by qualified and accordingly trained personnel.  In order to obtain the best results, the instructions contained in the manual must be followed. Any change to the indicated temperatures, times or any other step of the process can lead to poor results.

KIT COMPONENTS

The Kit includes 20 single test tubes of Histosonda Gastrin; 20 single test tubes of Proteinase K and 2 tubes of Anti-Digoxin antibody sufficient for 20 tests in total.  All products are lyophilized.

Histosonda Gastrin consists of a single stranded DNA fragment with a length of 343 nucleotides targeted against gastrin mRNA.  The DNA of this probe has been labeled with digoxigenin.

STORAGE CONDITIONS

Supplied reagents are stored at room temperature until their expiration date. After being reconstituted the probes will remain stable for two weeks at 4ºC in a DNAase-free environment.  The Anti-Digoxin can be stored at 4ºC for 1 month and the Proteinase K must be used immediately and cannot be stored.  Do not use these products after their expiration dates.

SAMPLES

Any paraffin block section in which Gastrin RNA presence is to be studied. Sections of 4-6 micrometers in width are sufficient to conduct the study. Preferably, the cut should be recent (no more than thirty days old). Assay results are not affected by block age. Studies have been carried out in the manufacturer's laboratories using 20 year old paraffin blocks with optimal results.

INTERPRETATION OF RESULTS

Samples in which Gastrin expression is observed will show a brownish color in the cell cytoplasm, which will contrast over the blue-violet background given by hematoxylin staining. The pathologist will evaluate the results according to their experience, drawing conclusions from the staining of the sample in parallel with the staining observed in positive and negative controls.

ASSAY LIMITATIONS

The Kit Histosonda Gastrin has been optimized to detect RNA expression in formalin-fixed, paraffin-embedded tissues. Its use is not recommended for other types of samples or preparation techniques.

The correct operation of this kit has been validated using the protocols indicated in the instructions manual. The use of other procedures or the modification of the recommended protocols may lead to erroneous results.

The results from this assay must be evaluated by the pathologist in combination with the rest of available patient clinical data.

In order to obtain optimal and reproducible results it is important to rigorously maintain the time and temperature conditions indicated in the procedure.

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