Micro-regional mapping of HbO[sub 2] saturations and blood flow following nicotinamide administration

Journal Article · Wed Jun 15 00:00:00 EDT 1994 · International Journal of Radiation Oncology, Biology and Physics; (United States)

DOI:https://doi.org/10.1016/0360-3016(94)90438-3· OSTI ID:6869144

Fenton, B M; Boyce, D J ^[1]

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1. Univ. of Rochester Medical Center, NY (United States)

Although nicotinamide administration has increased the radiosensitivity of experimental tumors, there is a scarcity of data detailing the underlying physiological mechanisms. The current study presents a method for quantifying both microregional distributions of intravascular HbO[sub 2] saturations and the presence or absence of blood flow in adjacent frozen tumor sections. Two murine tumor cell lines, KHT and SCCVII, were implanted and quick-frozen without the use of anesthetics. Nicotinamide was administered IP 1 h prior to freezing, and a fluorescent dye that preferentially stains cells adjacent to blood vessels was injected IV 1 min prior to freezing. To visualize the presence or absence of blood flow, six micron sections were first cut using a cryostat. The remaining frozen tumor block was then analyzed cryospectrophotometrically to determine intravascular HbO[sub 2] levels. While KHT HbO[sub 2] levels increased somewhat predictably following nicotinamide, the response in SCCVII tumors varied with distance from the tumor surface. Near the periphery, SCCVII HbO[sub 2] levels increased, but nearer the tumor center, HbO[sub 2] levels actually decreased. Perfused blood vessels were uniformly distributed throughout the tumor volume except in regions of necrosis. Even vessels containing no measurable oxygen remained perfused, as evidenced by the presence of the fluorescent marker. These results demonstrate that nicotinamide raises intravascular HbO[sub 2] saturations in both KHT and SCCVII tumors. This increase in oxygen delivery is not evenly distributed throughout the tumor volume in spite of a uniform distribution of perfused blood vessels. Blood flow in a substantial proportion of these vessels is most likely not sufficiently rapid to serve a functional purpose in terms of oxygen supply to the surrounding tumor tissue. 15 refs., 4 figs.

• OSTI ID: 6869144
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (United States), Vol. 29:3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
NICOTINAMIDE
RADIOSENSITIVITY
EXPERIMENTAL NEOPLASMS
HEMOGLOBIN
AMIDES
AZINES
CARBOXYLIC ACIDS
GLOBINS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
PYRIDINES
VITAMIN B GROUP
VITAMINS
560152* - Radiation Effects on Animals- Animals