Hideaki Anai

Clinicopathological characteristics of mucinous carcinoma of the colon and rectum

Clinicopathological significance of colorectal mucinous carcinoma (MC) remains controversial. The aim of the current study was to investigate the clinicopathological characteristics of colorectal MC.

Gastric cancer with p53 overexpression has high potential for metastasising to lymph nodes.

Overexpression of the tumour suppressor gene p53 was investigated immunohistochemically in 96 primary gastric carcinomas and 26 corresponding metastatic perigastric lymph nodes. Abnormalities in p53 expression were found in 52 (54%) of the 96 primary carcinomas. Tumours stained positively for p53 frequently metastasised to lymph nodes (the metastatic rate: 85%) compared to findings in those with negative p53 staining (64%, P < 0.05). Ninety-two percent (24/26) of the malignant cells in the lymph nodes stained positively for p53. When the DNA ploidy pattern of the tumour was determined by flow cytometry, the aneuploid tumours in p53 positive and negative groups accounted for 69% and 45%, respectively (P < 0.05). Proliferative activity of the tumour, as measured by Ki-67 labelling, was significantly higher (30.6 +/- 12.0%) in the p53 positive group than that (25.1 +/- 10.7%) in the p53 negative group (P < 0.05). Thus, gastric cancer with a mutant p53 has high proliferative activity and metastasis to lymph nodes will probably occur.

The ATP assay is more sensitive than the succinate dehydrogenase inhibition test for predicting cell viability

The succinate dehydrogenase inhibition (SDI) test and the adenosine triphosphate (ATP) assay, are both used for in vitro human tumor chemosensitivity testing. We exposed HeLa cells to various concentrations of mitomycin C for 1, 2 or 3 days and found that the decrease in number of viable cells correlated with that of succinate dehydrogenase (EC 1.3.99.1) activity and that of intracellular ATP level of the viable cells. In the dead cells, the ATP level was extensively decreased, but the succinate dehydrogenase activity remained at a level of 24% of that of mitomycin C-untreated viable cells, even on day 3. Thus, the ATP level better reflected the cell viability. In clinical situations, the succinate dehydrogenase activity and the ATP level are assayed in whole cells following exposure to anticancer drugs, therefore the activity remaining in the dead cells must be taken into consideration for the chemosensitive prediction with the SDI test, but not with the ATP assay. This higher sensitivity of the ATP assay will enable a more accurate prediction of cell viability.

In situ nick translation method reveals DNA strand scission in HeLa cells following heat treatment

DNA strand break in HeLa cells induced by heat was detected using the in situ nick translation method. The cells were incubated at 43 degrees C for various times (15, 30, 45, 60, 90 or 120 min) in Lab-Tek tissue culture chamber/slides and were fixed with ethanol/acetic acid on the slide glass. The break sites in DNA were translated artificially in the presence of Escherichia coli DNA polymerase I and 3H-labeled dTTP. The level of break sites in the DNA was visualized by autoradiographic observation of the grains. The DNA strand break appeared as early as 15 min, increased to 10.3-fold at 45 min of 43 degrees C treatment and this level related reciprocally to clonogenicity of the cell. The nick translation method thus provides a rapid in situ assay for determining heat-induced DNA damage of cultured cells, in a semi-quantitative manner.

Carcinoma of the thyroid manifested as hyperthyroidism caused by functional bone metastasis.

A rare case of hyperthyroidism in the presence of a functioning bone metastasis secondary to an occult thyroid cancer is reported. A 59-year-old womans pelvic bone metastasis was much too extensive and hypervascular to permit resection. An I-131 scan showed striking activity in the pelvic metastasis, which reflected ectopic excessive production of thyroid hormone by a functioning metastatic thyroid carcinoma. After total thyroidectomy, the patient received I-131 ablation and transcutaneous intra-arterial embolization therapy but her metastasis progressively enlarged. Microscopically, concomitant follicular and papillary cancer was found in close proximity to the thyroid. The patient now has vertebral metastases, and her hyperthyroid state still requires methymazole to prevent thyrotoxicosis.

5‐fluorouracil and uft‐sensitive gastric carcinoma has a high level of thymidylate synthase

The authors examined the relationship between the level of thymidylate synthase (TS) and the sensitivity to 5‐fluorouracil (5‐FU) and UFT, a combined oral preparation of 1‐(2‐tetrahydrofuryl)‐5‐fluorouracil (tegafur) and uracil in a molar ratio of 1:4. For the studies we used the subrenal capsule (SRC) assay and 15 human gastric cancer tissues. The TS levels were assayed by the ligand‐binding technique, using [6–3H]FdUMP. The relative variation of tumor size (ΔTuS/TuS0) was calculated to be as follows: ΔTuS/TuS0 = [(TuS6 – TuS0/TuS0] X 100 (%), where TuS6 was the tumor size on day 6 and TuS0 on day 0. The chemosensitivity was considered to be positive when ΔTuS/TuS0 in the treated group decreased to below –10%. Decrease in tumor size was marked in case of exposure to UFT (‐19.8 ± 13.0%) (mean ± standard deviation), compared with that to 5‐FU (‐9.0 ± 7.2%), with a statistically significant difference (P < 0.001). The TS level varied from 1.7 to 30.8 pmol/g gastric cancer tissue and the mean was 7.1 ± 7.2 pmol/g tissue. A correlation was noted between the TS level and decrease in size of the tumor exposed to 5‐FU (r = −0.671) or UFT (r = −0.758): gastric cancer tissue with higher level of TS is more sensitive to 5‐FU and UFT than is that with a lower TS level. These findings show that the sensitivity to 5‐FU and UFT of gastric cancer tissue is related to the TS level and that UFT shows promise for the treatment of patients with gastric cancer.

Usefulness of reconstruction with jejunal pouch in total gastrectomy for gastric cancer in early improvement of nutritional condition

BACKGROUND Roux-en-Y reconstruction with a jejunal pouch is a modified standard procedure in total gastrectomy for gastric cancer. The aim of the current study was to evaluate the usefulness of the reconstruction using a jejunal pouch in subsequent improvement of the nutritional condition of patients with gastric cancer after total gastrectomy. METHODS Sixteen patients with gastric cancer treated by total gastrectomy and reconstruction with simple Roux-en-Y from January 1993 to December 1996 and 14 patients treated by total gastrectomy and reconstruction with Roux-en-Y and jejunal pouch from January 1997 to December 1998 were investigated in regard to postoperative heartburn, changes in the body weight, and prognostic nutritional index. RESULTS Postoperative heartburn occurred in 1 patient (7.1%) among patients treated with Roux-en-Y and jejunal pouch and 3 (18.8%) among patients treated with simple Roux-en-Y. The body weight ratio at 1 year after operation in patients treated with Roux-en-Y and jejunal pouch (88.2% +/- 4.2%) was significantly higher than that in patients treated with simple Roux-en-Y (80.0% +/- 4.6%; P <0.01). The prognostic nutritional index ratios for patients treated with Roux-en-Y and jejunal pouch at 1 and 3 months after operation were 93.9% +/- 9.1% and 101.7% +/- 11.0%, respectively, and were significantly higher than that in patients treated with simple Roux-en-Y (86.2% +/- 8.8% and 88.1% +/- 8.2%, P <0.05 and P <0.01, respectively). CONCLUSIONS Reconstruction using a jejunal pouch in total gastrectomy is useful for an early improvement of the nutritional condition of patients with gastric cancer.

Sodium Succinate Enhances the Colorimetric Reaction of the in vitro Chemosensitivity Test: MTT Assay

We compared the colorimetric reactions between the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl 2H-tetrazolium bromide (MTT) assay and the succinate dehydrogenase inhibition (SDI) test, in order to evaluate the usefulness of the SDI test for in vitro chemosensitivity testing. The addition of sodium succinate enhanced the colorimetric absorbance at 565 nm in the MTT assay in a dose- and a time-dependent manner, in mouse sarcoma-180 (S-180) cells. At 10 microM of sodium succinate, a dose used in the SDI test, the absorbance of the MTT assay increased by about 2.5-fold in the S-180 cells and in 10 human tumor tissues. The absorbance in the SDI test correlated well with the viable cell number of S-180 cells (r = 0.9993). These results show that the SDI test, using MTT as a tetrazolium salt, has a higher sensitivity for predicting cell viability, compared to the MTT assay.

Excised Human Neoplastic Tissues Are More Sensitive to Heat than the Adjacent Normal Tissues

In tissues from patients subjected to gastrectomy or colectomy, the heat sensitivity was determined in the case of 23 neoplastic, 15 gastric, 8 colorectal, and the adjacent normal tissues, using the in vitro succinate dehydrogenase inhibition test. The succinate dehydrogenase (SD) activity of tissue fragments was assayed, following exposure to heat at 43 degrees C (heat treatment) or 37 degrees C (control) for 5, 10, 15 or 20 h. The sensitivity to heat treatment was estimated by the percentage of SD activity of the heat-treated cells, compared to that of control cells. The decrease in SD activity varied in the tumor tissue, following exposure to heat. The SD activity decreased to a greater extent in the tumor tissue than in the adjacent normal tissue, in each case. The mean +/- standard deviation of SD activity, following exposure to heat treatment for 20 h, was 32.1 +/- 14.0% for the tumour tissues and 52.4 +/- 10.4% for the adjacent normal tissues, with a statistically significant difference (p less than 0.01). These results show that the assay of heat sensitivity is meaningful for prediciting the effectiveness of hyperthermia and that hyperthermia has a selectivity for treating a malignant lesion.

UFT Is More Antineoplastic against Gastric Carcinoma than 5-Fluorouracil, 1-(2-Tetrahydrofuryl)-5-fluorouracil and 1-Hexylcarbamoyl-5-Fluorouracil

The sensitivity of human gastric cancer tissue to 5-fluorouracil (5-FU) and its analogues 1-(2-tetrahydrofuryl)-5-fluorouracil (FT), UFT and 1-hexylcarbamoyl-5-fluorouracil (HCFU) was determined, using the in vivo subrenal capsule (SRC) assay. The relative variation of tumor size (delta TS/TS0) was calculated as follows: delta TS/TS0 = (TS6-TS0/TS0) x 100%, where TS6 was the tumor size on day 6 and TS0 on day 0. The chemosensitivity was considered to be positive when delta TS/TS0 in the treated group decreased to below -10%. For their cytotoxic effects, 5-FU analogues are converted to 5-FU and positive correlations were noted between the tumor sizes of 5-FU and its analogues (5-FU vs. FT, r = 0.737; 5-FU vs. UFT, r = 0.653; 5-FU vs. HCFU, r = 0.709), in gastric tissues from 22 patients. The means +/- SD of tumor size were -8.5 +/- 11.5% for 5-FU, -8.3 +/- 16.0% for FT, -18.1 +/- 15.8% for UFT and -13.7 +/- 13.4% for HCFU. Decrease in tumor size was marked in case of exposure to UFT, compared with that to 5-FU (p less than 0.001), FT (p less than 0.001) and HCFU (p less than 0.05). 18% were sensitive to UFT and resistant to 3 other drugs. Thus, UFT proved to be the most effective among 5-FU and its analogues for decreasing the size of gastric cancer tissues.