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BACKGROUND: It is difficult to differentiate histologically between benign and malignant follicular-type tumours of the thyroid gland. The present study evaluated whether sentinel lymph node (SLN) biopsy was helpful in obtaining the correct diagnosis of malignant follicular-type tumours, as metastasis to the lymph nodes is sufficient evidence for a diagnosis of cancer. METHODS: SLN biopsy was performed for 37 follicular-type tumours suspected to be malignant on the basis of preoperative examinations, but for which the diagnosis had not been confirmed. RESULTS: SNs were identified in 32 of 37 procedures. SLN metastases were found in four of 12 patients with a malignant tumour identified by intraoperative frozen-section analysis. There was one false-negative but no false-positive diagnoses. Frozen-section analysis of the tumour itself identified only one follicular cancer. The accuracies of preoperative imaging methods were lower than that of SLN detection. CONCLUSION: Detection of SLN metastasis was helpful in diagnosing follicular thyroid cancer and thus enabling one-stage surgery.

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BACKGROUND: Although liver transplantation has become a standard therapy for diseases such as fulminant hepatitis and cirrhosis, the lack of donor organs remains a major problem. One solution is the development of transplantable hepatocytes. The metabolic characteristics as well as function and adaptation of hepatocytes (R-EES-hep cell) derived from rat early embryonic stem cells were examined after transplantation into rats with surgically induced liver failure. METHODS: Rat hepatocyte cell lines were established from early embryonic stem cells cultured in the presence of embryotrophic factors by colony cloning methods. The cell lines were established from two cell embryos taken from spontaneous dwarf rats using the novel method of Ishiwata et al. Morphologic differentiation as well as albumin and bilirubin production were observed by immunostaining. R-EES-hep cells were transplanted into the spleens of 90% hepatectomized, surgically induced liver failure rats to analyze survival rates. RESULTS: When cultured in type I collagen gel the cells formed cordlike structures resembling the liver. Both albumin and bilirubin production were observed when transplanted; the spleen was converted into a liver-like structure with prolonged survival of the 90% hepatectomized rats for up to 3 months up to the time of killing. CONCLUSIONS: R-EES-hep cells showed many of the distinctive metabolic characteristics of the liver. These cells may be efficient for further research and application for hepatic cell transplantation to treat liver insufficiency patients and as biologic artificial organs.

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The shortage of human livers available for hepatocyte isolation limits its clinical application. The availability of cloned, conditionally immortalized hepatocytes that could be grown in culture but would lose their transformed phenotype and provide metabolic support upon transplantation would greatly facilitate the treatment of acute liver failure. Toward this goal, we transduced isolated Lewis rat hepatocytes using a replication-defective recombinant retrovirus capable of transferring a gene encoding a thermolabile mutant simian virus 40 T antigen (SV40ts). The cloned, immortalized hepatocytes proliferate at 33 degrees C. At the nonpermissive temperatures (37-39 degrees C), they stop growing and exhibit characteristics of differentiated hepatocytes. These cells did not produce tumors when transplanted in mice with severe combined immunodeficiency disease or in syngeneic rats. To induce acute liver failure, Lewis rats were subjected to 90% hepatectomy (Hpx) and given 5% oral dextrose. All rats that did not undergo hepatocyte transplantation died within 96 hr. Fifty percent of rats that received intrasplenic injection of 10 x 10(6) primary Lewis rat hepatocytes (G2, n=6) or 10 x 10(6) SV40ts-conditionally immortalized (SV40ts-ci) hepatocytes (G3, n=8) 1 day before 90% hepatectomy survived, whereas 80% of rats that received an intraperitoneal injection of 200 x 10(6) primary Lewis rat hepatocytes (G4, n=10) or 200 x 10(6) SV40ts-ci hepatocytes (G5, n=10) on the day of hepatectomy survived. Survival after intraperitoneal injection of a cellular homogenate of 200 x 10(6) primary Lewis rat (G7, n=9) or SV40ts-ci hepatocytes (G8, n=10) on the day of Hpx was 33% and 40%, respectively, whereas survival after intraperitoneal injection of 200 x 10(6) Lewis rat bone marrow cells (G6, n=7) was 29%. Thus, transplanted, conditionally immortalized hepatocytes can be as effective as primary hepatocytes in supporting life during acute liver insufficiency. This work represents the first step in developing an hepatocyte cell line that would partially alleviate the organ-donor shortage and could be of potential clinical value.

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A comparative study of ²01;Tl and &sup99m;Tc-methoxy-2 isobutyl isonitrile (&sup99m;Tc-MIBI)was performed in 39 breast tumors. ²01;Tl scintigraphy was carried out in 24 breast tumors and &sup99m; Tc-MIBI scintigraphy in 15. The sensitivity of ²01;Tl for malignant tumors was 100%(22/22), but specificity was 0%(0/2). On &sup99m;Tc-MIBI scintigraphy, the sensitivity for malignant tumors was 83.3%(10/12) and specificity was 100%(3/3). &sup99m;Tc-MIBI might be more useful for the diagnosis of breast tumors, because the tumor/background ratio of &sup99m;Tc-MIBI was significantly higher than that of ²01;Tl. In addition, ²01;Tl scintigraphy and &sup99m;Tc-MIBI scintigrtaphy showed the same degree of accuracy (93.3%) in detecting lymph node metastasis. Moreover, when either ultrasonography (US) with ²01;Tl or &sup99m;Tc-MIBI scintigraphy was positive for lymph node metastasis, the accuracy of detection became 94.4% The combined use of ultrasonography and scintigraphy might improve the accuracy of diagnosis of lymph node metastasis.

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