Three people sustained injury, including one man who was briefly hospitalized, and four families were left temporarily homeless, when flames spread quickly from an abandoned home to an occupied apartment building early Wednesday morning.    The Los Angeles Fire Department was summoned at 1:13 AM on April 11, 2018 to 7243 Lankershim Boulevard in North Hollywood, where firefighters arrived promptly to find a section of both floors at a two story apartment building well involved after flames spread from a nearby vacant two story home.   Bystanders who witnessed the inferno ran from door-to-door at both levels of the apartment building prior to the Fire Department's arrival, awakening residents who were mostly able to escape unharmed.   Two men and one woman from the neighboorhood did sustain minor injuries, and were evaluated by LAFD Paramedics. Only one man - who sustained minor burns to his back, arms and hand, accepted ambulance transportation to an area hospital, where he was treated and released later in the day.    Eighty-seven firefighters under the command of Battalion Chief Dale Drummond extinguished the flames in just 38 minutes. Despite their efforts that saved the bulk of the large apartment building, a total of four apartment units (two upstairs and two downstairs) sustained severe  damage, and were considered untenable.    Volunteers from the American Red Cross assisted the eight displaced residents, while Inspectors from the City's Department of Building & Safety examined the apartment building to determine what repairs would be necessary before residents of those units could return. The vacant single family home was a total loss.    Monetary damage from the fire is still being tabulated. Though there had been a previous fire in the abandoned home where Wednesday's blaze is presumed to have originated, the specific genesis of the blaze remains the focus of an active investigation by Los Angeles Fire Department investigators.    Dispatched Units: CM42 EM14 BC12 E27 E102 E278 T78 EM11 UR88 T27 E227 UR27 HR3 BC5 RA77 RA81 RA39 EM17 AR2 RT59 EM14