Hirobumi Kumazawa

Cyclin-D1-gene amplification is a more potent prognostic factor than its protein over-expression in human head-and-neck squamous-cell carcinoma.

To evaluate the prognostic significance of cyclin D1 protein/gene expressions in human head‐and‐neck squamous‐cell carcinoma (HNSCC), we examined amplification of the cyclin‐D1 gene (CCND1) by the differential PCR method and over‐expression of cyclin‐D1 protein by immunohistochemistry in 45 paraffin‐embedded sections from HNSCC. Amplification of CCND1 was found in 10 (22%) cases and over‐expression of cyclin D1 was found in 24 (53%) cases. CCND1 amplification was also found in 3 (25%) of 12 cases of dysplastic lesions adjacent to HNSCC. The overall 5‐year survival of patients with CCND1 amplification or with protein over‐production was significantly lower than that of patients without (p < 0.0001 and p < 0.05, respectively). However, with multivariate analysis, only amplification of CCND1 retained an independent prognostic value (p = 0.0018). These suggest that CCND1 amplification occurs at early stages of HNSCC tumorigenesis and is a more useful prognostic factor than over‐expression of cyclin D1 in HNSCC. Int. J. Cancer 74:576–581, 1997.© 1997 Wiley‐Liss, Inc.

A simple method to estimate the secretion of saliva from minor salivary glands using iodine-starch reaction

Objective/Hypothesis This study was undertaken to detect the faculty of secretion of saliva from minor salivary glands by analyzing a color reaction on a test tape containing iodine and starch that was applied on the lower lip.

Effects of Acetazolamide on Acid-base Balance in the Endolymphatic Sac of the Guinea Pig

The effects of acetazolamide, a carbonic anhydrase inhibitor, on acid-base parameters in the endolymphatic sac of the guinea pig were investigated using ion-selective microelectrodes. Bicarbonate concentration was reduced and pH shifted to being acidic immediately after administration of acetazolamide. Chloride concentration in the endolymphatic sac increased after carbonic anhydrase inhibition. These findings provide evidence of an active function of carbonic anhydrase in the endolymphatic sac and suggest that carbonic anhydrase activity is involved in the formation of endolymphatic sac fluid.

Influence of Serum Derived from Patients with Head and Neck Cancer on Natural Killer Cell Activity

The influence of serum from 23 patients with head and neck cancer on natural killer (NK) cell activity was analyzed using a double-layer agar assay, in which NK cells show an activity to inhibit the colony growth of K562 cells. In contrast to normal serum (or no treatment), serum from cancer patients reduced the inhibitory activity of NK cells, not only of autologous NK cells but also of allogeneic NK cells. These results suggest that the serum of patients with head and neck cancer may have some inhibitory factors on NK cell activity and may be involved in host resistance to tumor growth in vivo.

Intracellular Calcium Changes and Chemosensitivities of Human Epidermoid Carcinoma Cell Lines after Exposure to Cisplatin

In order to elucidate the mechanisms of cisplatin (cis-diamminedichloroplatinum; CDDP)-resistant tumor cells, we previously established a CDDP-resistant KB cell line (KBrc cells) from a parental KB cell line derived from epidermoid carcinoma (KB cells). The KBrc cells were resistant to 5 kinds of platinum (Pt) drugs. Intracellular Pt concentrations in KBrc cells were lower than in KB cells. Decrease of intracellular Pt concentrations was one of the CDDP-resistant mechanisms. When we measured changes of intracellular calcium ion concentration ([Ca2+]i) during exposure to high-dose CDDP, a sustained elevation of the [Ca2+]i level was observed in the KB cells. These results suggest that the mechanisms underlying CDDP resistance involve changes in calcium channels and an alteration of calcium homeostasis in the tumor cell line.

Morphologic Analysis of Three-Dimensional Tumors Developed in Fibrin Matrix and Agar Culture System

The three-dimensional growth of cultured tumor cell lines (HT29, a colon adenocarcinoma cell line; M21, a melanoma cell line; KB, a nasopharyngeal carcinoma cell line) has been investigated in an agar culture system with a fibrin matrix in vitro. The tumor cells developed to tumors 3 x 3 mm in diameter after 10 days in culture in vitro. This size was large enough to allow histologic examination. The tumor cells located in the surface area of the three-dimensional tumor seemed to grow well. However, the tumor cells in the center degenerated or did not proliferate, indicating a lack of nutrition and/or anoxia in the center. The histologic comparison between the xenografted tumors on nude mice and the three-dimensional tumors in vitro suggests that the structures of the three-dimensional tumors were comparable, especially in the surface area, to the xenografted tumors. Furthermore, the antitumor effect of mitomycin C on the three-dimensional tumors was found to be dose-dependent.

Effect of lymphokine-activated killer cells on head and neck tumours in nude mouse model.

The present study was designed to investigate the in vivo effect of local application of lymphokine-activated killer (LAK) cells on the growth of tumours implanted under the renal capsule in nude mice, and especially to test whether large granular lymphocytes (LGL), regarded as natural killer (NK) cells, are the main precursor of LAK cells in vivo. Our results showed that the local application of LAK cells inhibited the growth of tumours in the head and neck region. The growth of tumours implanted under the renal capsule was inhibited by local application of 1 x 10(7) recombinant interleukin-2 (rIL-2) activated non-adherent lymphocytes, but the inhibitory effect was almost the same as produced by 3 x 10(6) rIL-2-activated LGL application. The findings indicate that the rIL-2-activated LGL are the main effectors in inhibiting tumour growth. In addition, rIL-2-activated non-adherent lymphocytes as well as LGL significantly prolonged the number of days of 50% survival and mean survival time of nude mice, in which HLaC78 cells, from a laryngeal tumour cell line, were injected into the subrenal capsule space with effector cells at various effector: target (E:T) ratios. The results indicate that the application of LAK cells may be useful in the treatment of patients with head and neck tumours.

Establishment of a Cisplatin-Resistant KB Cell line and its Characterization

A KB cell line resistant to cisplatin (KB-rc cell) was successfully established by exposing KB cells to a gradually increasing dose of cisplatin in vitro. The concentration of cisplatin required for 50% inhibition of KB-rc cell proliferation was 1.0 micrograms/ml, while that of KB cells was 0.5 micrograms/ml. Studies of KB-rc cell kinetics after treatment with cisplatin, using flow cytometry, showed that the G2M phase block was inhibited on day 3, and that G0G1 phase cells started to increase on day 5. Therefore, cisplatin-resistance is related to inhibition of the G2M phase block. The decrease of KB-rc cell viability with cisplatin was accelerated by the addition of a Ca antagonist (verapamil) and S phase cells increased on day 3. Verapamil may therefore be useful for enhancement of the effect generated by cisplatin on cisplatin-resistant tumor cells.

Xenotransplantation von Akustikusneurinomgewebe auf einen immundefizienten Mäusestamm

Akustikusneurinome sind histologisch benigne Tumoren des VIII. Hirnnervs. Sie verursachen eine sensorineurale SchwerhOrigkeit, GleichgewichtsstOmngen und oftmals eine Kompression des Hirnsta

Chemosensitivity Testing of Human Mouth Carcinoma Cell Line

The chemosensitivity of KB cells derived from oral epidermal carcinoma to various antitumor agents was analyzed using the MTT[3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H tetrazolium bromide] assay. Optical density (OD) for MTT assay was measured with dual wavelengths. The chemosensitivity of the drugs was evaluated by the 50% OD (OD50) of each drug concentration in the control group. Five platinum (Pt) drugs and 3 anthracycline (AC) drugs were used in this study. The chemosensitivity differed among the 5 Pt drugs. No significant difference was observed among the 3 AC drugs. A linear increase in OD corresponding to an increase in number of cells was observed. When 0.1 M sodium succinate (S.S.) was added to 0.4% MTT, the sensitivity increased five-fold compared to the control group without S.S. The MTT assay is a precise, rapid, easy and inexpensive experimental system useful for evaluation of antitumor drug sensitivity on tumor cell lines.