Abstract
We have used a newly-developed spectrum analysis apparatus to detect and to trace the dynamics of hematoporphyrine derivative (HpD) in the tumor-bearing mouse. Also we have detected the fluorescence of gastric cancer via fiberscope following injection of HpD and evaluated whether the spectrum analysis following injection of HpD can be used to diagnosis gastric cancer. Eighteen gastric cancer-bearing mice were used in the fundamental study. Following intraveneous injection of 20 mg/kg of HpD, measurment of relative concentration of HpD in the normal skin and transplanted tumor area were began. These measurements were performed until 96 hours after injection in order to realize the dynamics of HpD. The measurement of relative concentration of HpD in vivo were performed using optical density method which concerning several apparatus as illustrated in the Figure 1 and 2. An additional experiment using 12 normal nude mice approved that this method could measure exactly the relative concentration of HpD in vivo (Table 1). The relative concentration of HpD in the normal area was significantly higher than that in the tumor area until 15 minutes after injection of HpD. Then, the concentration of HpD in the normal area decreased gradually. while that in the tumor area increased constantly. Finaly, the concentration of HpD in the tumor area showed a significant higher concentration of HpD than normal area since four hours after injection of HpD (Figure 4). Accompanying with the results showed in the Table 2 we considered that HpD had the property of tumor accumulation rather than tumor affinity. Several additional data showed in the Figure 3 and Table 3 suggested that the impaired excretion of binding complex of HpD and serum albumin in the tumor area may be the mechanism of the tumor accumulation of HpD. The fundamental study using gastric cancer-bearing mice suggested that fluorescence spectra analysis following injection of HpD may be used to diagnosis gastric cancer via fiberscope. Based on this result, a 73 years old male suffering from advanced gastric cancer and severe uremia had been tried. Seventy two hours after intraveneous injection of HpD 2.5 mg/kg, photoradiation therapy for cancer were performed. Just before performance of photoradiation therapy, fluorescence spectrum analysis of tumor and normal area were done. The method and apparatus for examination via fiberscope wereillustrated in the Figure Z. The tip of the spectra analyzing fiber was contacted to the surface of gastric mucosa to examine the fluorescence. As the curves showed in the Figure 5 the fluorescence spectrum of the cancer area has a high peak at the 630nm of wavelength. which is quite different from the spectrum of normal area having 580 nm and 600 nm, mainly. The HpD concentration in the cancer area (A-A') was also noted to be higher than that in the normal antrum mucosa (B-B'). In conclusion, this study approved that HpD has the property of tumor accumulation rather than tumor affinity. And the fluorescence spectra analysis of stomach following injection of HpD can be used to diagnosis gastric cancer via endoscopy.
