The effect of nicotinamide on microregional blood flow within tumours assessed using laser Doppler probes.
Laser Doppler probes have been used to provide real-time spatial flow mapping of microregional erythrocyte flux within the murine Sarcoma F (SaF). The results demonstrate that fluctuations in microregional red blood cell flux are a common feature of SaF tumours, with approximately 50% of regions demonstrating a change of at least a factor of 2 over a one-hour sampling period and 16% of regions showing a greater than 5-fold change. Administration of 250 mg/kg nicotinamide induced a small reduction in the number of microregions showing fluctuations, 9% of regions demonstrated large fluctuations (i.e., > or = 5) relative to 16% in control tumours. At a dose of 500 mg/kg, the number of changes in microregional erythrocyte flux was increased. However, unlike either untreated or nicotinamide 250 mg/kg pretreated animals, these changes were mostly increases in microregional flow. Indeed, 12 of the 13 changes by a factor of 5 or greater, observed following nicotinamide at 500 mg/kg, were increases. This effect on microregional flow translated into only a 25% increase in macroregional flow determined by averaging all the regions sampled.
Hill
S A
SA
CRC Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, U.K.
Chaplin
D J
DJ
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D004912:Erythrocytes / Q000502:physiology; D017078:Laser-Doppler Flowmetry / Q000379:methods; D051379:Mice; D008808:Mice, Inbred CBA; D009536:Niacinamide / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects*; D012513:Sarcoma, Experimental / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology; D013997:Time Factors; D014463:Ultrasonography
D009536:Niacinamide