In vitro autoradiographic localization of angiotensin-converting enzyme in sarcoid lymph nodes

Journal Article · Mon Sep 01 00:00:00 EDT 1986 · Chest; (United States)

DOI:https://doi.org/10.1378/chest.90.3.315· OSTI ID:5008317

Allen, R K; Chai, S Y; Dunbar, M S; Mendelsohn, F A

Angiotensin-converting enzyme (ACE) was localized in sarcoid lymph nodes by an in vitro autoradiographic technique using a synthetic ACE inhibitor of high affinity, /sup 125/I-labelled 351A. The lymph nodes were from seven patients with active sarcoidosis who underwent mediastinoscopy and from six control subjects who had nodes resected at either mediastinoscopy or laparotomy. Angiotensin-converting enzyme was localized in the epithelioid cells of sarcoid granulomata in markedly increased amounts compared with control nodes, where it was restricted to vessels and some histiocytes. In sarcoid lymph nodes, there was little ACE present in lymphocytes or fibrous tissue. Sarcoid nodes with considerable fibrosis had much less intense ACE activity than the nonfibrotic nodes. The specific activity of ACE measured by an enzymatic assay in both the control and sarcoid lymph nodes closely reflected the ACE activity demonstrated by autoradiography. Sarcoid lymph nodes with fibrosis had an ACE specific activity of half that of nonfibrotic nodes (p less than 0.05). There was a 15-fold increase in specific ACE activity in sarcoid nodes (p less than 0.05) compared to normal. Serum ACE was significantly higher in those sarcoid patients whose lymph nodes were not fibrosed compared with those with fibrosis (p less than 0.01). This technique offers many advantages over the use of polyclonal antibodies. The 351A is a highly specific ACE inhibitor, chemically defined and in limitless supply. This method enables the quantitation of results, and autoradiographs may be stored indefinitely for later comparison.

• Research Organization: Univ. of Melbourne Austin Hospital, Australia
• OSTI ID: 5008317
• Journal Information: Chest; (United States), Vol. 3
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
LYMPH NODES
AUTORADIOGRAPHY
MONOCLONAL ANTIBODIES
DIAGNOSTIC USES
ANGIOTENSIN
ENZYMES
IODINE 125
LABELLED COMPOUNDS
PATIENTS
ANTIBODIES
BETA DECAY RADIOISOTOPES
CARDIOVASCULAR AGENTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LYMPHATIC SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
USES
VASOCONSTRICTORS
550601* - Medicine- Unsealed Radionuclides in Diagnostics