Dependency of two firebase "tables"


Hello everybody,

in list.ts i am trying to connect to two tables of my database with angular fire:

itemListRef$: Observable;
profileListRef$: Observable;
item = {} as Item;
profile = {} as Profile;

constructor(public navCtrl: NavController, private database: AngularFireDatabase,
public alertCtrl: AlertController,) {

this.itemListRef$ = this.database.list(`/item`).valueChanges();
this.itemListRef$.subscribe(task => this.item = item);  
this.profileListRef$ = this.database.list(`/profile/${this.item.userID}`).valueChanges();
this.profileListRef$.subscribe(profile => this.service = profile); 


In table “item” is the information about profile key saved. With this key I want get the information like username or review from “profile”.
How can I get the data from the “profile” table with the user information from the table “item”?

Is something like this possible?