Malignancies of human thyroid tumors and dynamic magnetic resonance imaging (MRI)

Time intensity curves for gadolinium-diethylene triaminepentacetic acid (Gd-DTPA) enhanced magnetic resonance imaging (MRI), namely dynamic MRI, were determined for thyroid diseases and compared with findings of histopathologic examination. Time intensity curves for solid lesions were determined, excluding cases with secondary changes such as calcification, hemorrhage, necrosis and fibrosis. Three different patterns of time intensity curves were observed: rapid washout, delayed washout and no change. In our previous study, malignant grades of thyroid tumors were estimated immunohistochemically by epidermal growth factor receptor (EGFR) antibody. In most of malignant diseases and a few benign diseases that had marked cell proliferative activity with staining EGFR strongly, the time intensity curve displayed a delayed washout pattern, in which intensity was above 1/2-maximal value within 10 min after injection Gd-DTPA. Almost all benign diseases and a few well differentiated carcinomas displayed a rapid washout pastern, in which intensity was decreased to lower than 1/2 of peak grade within 10 min following injection and showed staining EGFR weakly. Benign diseases showing no change of time intensity curve, did not almost show aEGFR positive cell. These findings suggested that the time intensity curve obtained from dynamic MRI might indicate differentiated grades and cell proliferating activity of thyroid tumors.     

Morphological and functional differentiation of human thyroid cells in collagen gel culture

Objective: cultured human thyroid cells in collagen gel culture were examined on cell morphology and the production of thyroglobulin (Tg), triiodothyronine (T3) and thyroxine (T4) which are components of functional differentiation. Methods: thyroid cells obtained from normal human thyroid tissues (four cases), follicular adenoma tissues (three cases), papillary carcinoma tissues (three cases), and follicular carcinoma tissue (one case), were cultured in collagen gel. Then these cultured cells were observed on cellular morphology and production of Tg, T3 and T4. Moreover, changes in morphological characteristics and production of Tg, T3 and T4 induced by addition of thyroid stimulating hormone (TSH) and epidermal growth factor (EGF) to medium in collagen gel culture were determined. Results: normal and tumor cells in collagen gel culture formed colonies and follicles with Tg production, similar to in vivo-like three-dimensional cellular structures and functions. Normal thyroid cells stimulated TSH induced more Tg and produced morphological changes, i.e. enlarged follicular lumens and increased the height of follicular cells, but did not promote cell proliferation. Reversely, normal thyroid cells stimulated with EGF promoted cell proliferation, but did not change morphological findings and did not increase production of Tg, T3 and T4. Conclusion: these findings suggest that collagen gel culture is useful for observing the effects of stimulation by cell growth factor on the morphological and functional differentiation of human thyroid cells.     

Cell proliferation and death of growth plate chondrocyte caused by ischemia and reperfusion.

The aim of this study was to assess the short-term response of cell kinetics of growth plate chondrocytes under conditions of warm ischemia and reperfusion. To understand the time-course changes that occur after reperfusion, 0 and 6 h of warm ischemia was produced in the right hindlimb of 35-day-old Wistar rats by isolating the vascular pedicle occlusion. The animals were killed at 12, 24, 48, or 96 h postoperatively after reperfusion, and proximal tibia growth plates were investigated. To investigate the effect of the ischemia period on the kinetics of growth plate chondrocytes, 0, 2, 4, 6, and 8 h of ischemia was induced, and the animals were killed for evaluation 24 h after reperfusion. For evaluation of cell kinetics, BrdU was used to observe the changes in cell proliferation of growth plate chondrocytes, and TUNEL was used to estimate the changes in rate of cell death. In the time-course study, both 0 and 6 h of ischemia increased cell proliferation at 12 and 24 h after reperfusion; however, at 48 and 96 h, the proliferation rate was not further increased. At 12 and 24 h postoperatively, 6 h of ischemia increased chondrocyte proliferation more than 0 h of ischemia with significant differences; 6 h of ischemia led to an increased cell death rate at 12, 24, and 48 h postoperatively, whereas 0 h of ischemia did not affect the cell death rate. In the ischemia time-dependent study, the cell proliferation rate induced by 4 h of ischemia was highest in all controlled periods of ischemia. Cell death rate increased gradually with increases in ischemia time 24 h after reperfusion. This experiment showed that ischemic damage causes short-term postoperative changes in the kinetics of growth plate chondrocytes.     

Expression of vascular endothelial growth factor-C and its receptor in invasive micropapillary carcinoma of the breast

Invasion to lymphatic vessels and metastasis to lymph nodes are frequent complications in invasive micropapillary carcinoma (IMPC) of human breast cancer. Vascular endothelial growth factor-C (VEGF-C) and its receptor, VEGFR-3 have been implicated as the important factors in the formation of lymphatic vessels and recent experimental evidence strongly suggests that lymphangiogenesis in tumor promotes lymphatic metastasis. To clarify the mechanism of its occurrence, the expression of VEGF-C, VEGFR-3 and lymphatic vessel density (LVD) was examined in 40 cases of IMPC (pure and mixed type) and in 40 cases of pseudo-IMPC. Cytoplasmic expression of VEGF-C and VEGFR-3 were more frequent in tumor cells of IMPC compared to those of pseudo-IMPC. A significant positive correlation was found between the expression of VEGF-C and VEGFR-3 in both IMPC and pseudo-IMPC. The expression of VEGF-C was also significantly associated with higher peritumoral LVD, lymphatic invasion and number of lymph node metastasis in IMPC. These findings suggest that VEGF-C promotes the proliferation of peritumoral lymphatic vessels and that lymphatic invasion and metastasis to lymph nodes are frequently induced in IMPC of breast.     

Difference in cytotoxicity against hepatocellular carcinoma between liver and periphery natural killer cells in humans

In rodents, liver natural killer (NK) cells have been shown to mediate higher cytotoxic activity against tumor cells than do peripheral blood (PB) NK cells. However, such differences between liver and PB NK cells have not been extensively investigated in humans. The phenotypical and functional properties of NK cells extracted from liver perfusates at the time of living donor liver transplantation were investigated. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a critical molecule for NK cell-mediated anti-tumor cell killing, was not expressed by freshly isolated PB NK cells or by liver NK cells. Stimulation with interleukin (IL)-2, significantly up-regulated the expression of TRAIL on liver NK cells, but this effect was barely observed on PB NK cells. Donor liver NK cells showed the most vigorous cytotoxicity against HepG2, a hepatocellular carcinoma (HCC) cell line, after IL-2 stimulation (90.5% +/- 2.2% at E: T = 10:1), compared with donor and recipient PB NK cells and recipient liver NK cells (64.8% +/- 8.2%, 56.1% +/- 8.9%, and 34.6% +/- 7.5%, respectively). IL-2 stimulation resulted in an increased expression of killing inhibitory receptors on liver NK cells in parallel with TRAIL expression. Consistently, the cytotoxicities of IL-2-stimulated donor liver NK cells against self and recipient lymphoblasts were negligible. In conclusion, adoptive transfer of IL-2-stimulated NK cells extracted from donor liver graft perfusate could mount an anti-tumor response without causing toxicity against 1-haplotype identical recipient intact tissues. These findings present a concept to prevent recurrence of HCC after liver transplantation.     

Atpenins,potent and specific inhibitors of mitochondrial complex II (succinate-ubiquinone oxidoreductase)

Enzymes in the mitochondrial respiratory chain are involved in various physiological events in addition to their essential role in the production of ATP by oxidative phosphorylation. The use of specific and potent inhibitors of complex I (NADH-ubiquinone reductase) and complex III (ubiquinol-cytochrome c reductase), such as rotenone and antimycin, respectively, has allowed determination of the role of these enzymes in physiological processes. However, unlike complexes I, III, and IV (cytochrome c oxidase), there are few potent and specific inhibitors of complex II (succinate-ubiquinone reductase) that have been described. In this article, we report that atpenins potently and specifically inhibit the succinate-ubiquinone reductase activity of mitochondrial complex II. Therefore, atpenins may be useful tools for clarifying the biochemical and structural properties of complex II, as well as for determining its physiological roles in mammalian tissues.     

Frequent loss of heterozygosity on chromosome 10p14-p15 in esophageal dysplasia and squamous cell carcinoma

High frequencies of loss of heterozygosity (LOH) on chromosome 10p14-p15 have been reported in various tumors, including glioma, pulmonary carcinoid and cervical, hepatic and prostatic carcinomas. These findings suggest the presence of a tumor suppressor gene at the loci. However, analysis of LOH on chromosome 10p14-p15 in esophageal tumors has not been reported. Therefore, we examined LOH on chromosome 10p14-p15 in 88 esophageal squamous cell carcinomas (SCC) (35 superficial- and 53 advanced-types) and 44 dysplasias by microsatellite assay. Five oligonucleotide primer sets for microsatellite loci D10S191, D10S501, D10S559, D10S558 and D10S249 were used. In dysplasias, frequent LOH was detected with markers D10S191 (26%) and D10S249 (33%). In superficial esophageal SCCs, frequent LOH was detected with markers D10S191 (26%), D10S559 (50%), D10S558 (29%) and D10S249 (33%). In advanced esophageal SCCs, we found frequent LOH was detected with markers D10S191 (38%), D10S501 (25%) and D10S559 (30%). There were no significant correlations between LOH on chromosome 10p14-p15 and clinicopathologic features, including patient age, sex, tumor location, depth of invasion and lymph node metastasis. These data suggest that a putative tumor suppressor gene for esophageal carcinogenesis may be located on chromosome 10p14-p15 and that malfunction of this gene may be involved in the development but not progression of esophageal tumors.     

Two case reports of complete regression of liver metastases from colorectal cancer after locoregional immunochemotherapy

Hepatic arterial infusion (HAI) with pharmacokinetic modulating chemotherapy (PMC) has been well known to be one of the most effective protocols for unresectable liver metastases from colorectal cancer. PMC is a combination of oral UFT and continuous hepatic arterial 5-FU infusion. We present herein the cases of two patients with multiple liver metastases from colorectal cancer in whom complete regression (CR) was achieved by HAI with PMC in combination with Lentinan (immunostimulator). These patients received HAI via an implantable port system with a 4-24-hour continuous perfusion of 5-FU at 1,000 mg/m2 plus Lentinan at 2 mg/body once a week, and oral administration of UFT at 200-300 mg/m2/day everyday. CR of all metastatic lesions in the liver was achieved 4 months after the initiation of the treatment in both patients. One patient maintained CR for 3 months, but he died due to a recurrence of liver metastases and peritoneal dissemination 19 months after the initiation of the treatment. The other patient has been well without recurrence for 21 months. Because the liver is the largest immunologic organ, Lentinan could have activated lymphocytes and macrophages in the liver. Judging from the clinical experience of these two cases, HAI with PMC in combination with Lentinan could be one of the most promising treatment strategies for unresectable liver metastases from colorectal cancer.