problem with call back function in gui

here,in push button22 I load the text from a file into the edit box named "mesage_length" .now i want to use the text in the retrive_ok funtion. how can I do that ?? plz help

{% --- Executes on button press in pushbutton22. function pushbutton22_Callback(hObject, eventdata, handles)

[filename,pathname,filterindex] = uigetfile('*.txt')

file_extention=[pathname,filename];

set(handles.message_length1,'String',file_extention)

function retrieve_ok_Callback(hObject, eventdata, handles)

image_string=get(handles.image2,'String');

text_string1=get(handles.message_length1,'String');

text_string=str2num(text_string1);

retrieve(image_string,text_string*2);}