DECLARE @string sysname;
SELECT @string = '< search string >';
SELECT
OBJECT_NAME(major_id) AS ObjectName,
USER_NAME(grantor_principal_id) AS Grantor,
USER_NAME(grantee_principal_id) AS Grantee,
p.permission_name
FROM
sys.database_permissions p
WHERE
OBJECTPROPERTY(major_id, 'IsMSSHipped') = 0 AND
USER_NAME(grantee_principal_id) = @string
ORDER BY
OBJECT_NAME(major_id), USER_NAME(grantee_principal_id), permission_name;