Superoxide dismutase in hepatocellular carcinoma affects patient prognosis

BACKGROUND/AIMS

The free radicals play an important role in the pathogenesis of neoplastic transformation of the tissues. Superoxide dismutase is a metalloenzyme, protecting the cells from oxygen radical insult. The superoxide dismutase activity may therefore alter the cellular signaling pathways against the insults derived from oxidative stress especially in the tumor tissues. Therefore, it is considered that superoxide dismutase activity is crucial in affecting the survival of the cancer bearing patients. This study aims to investigate the level of superoxide dismutase activity in hepatocellular carcinoma tissues and correlate this with patients' survival after surgery for hepatocellular carcinoma.

METHODOLOGY

Thirty-six patients who had hepatectomy for hepatocellular carcinoma at the National Taiwan University Hospital from 1992 to 1993 were included in this study. Superoxide dismutase activity of the tumor tissues was determined. The results were correlated with the patients' survival. The patients were grouped based on their postoperative survival time. Those patients who were deceased less then one year after surgery were in group I. Group II included patients who survived more than one year but less than 3 years after operation. Group III patients survived more than 3 years but less than 5 years. Ten patients who survived longer than 5 years after surgical intervention were in group IV. Data were expressed as mean and analyzed with ANOVA.

RESULTS

The demographic and clinical information of patients, such as age, gender, plasma albumin, globulin, alpha-fetoprotein levels, and hepatitis markers were comparable among these groups. The superoxide dismutase levels in the hepatocellular carcinoma were significantly higher in group IV than the other three groups (P < 0.05). Similarly, the superoxide dismutase levels of the hepatocellular carcinoma tissues from group III patients were significantly greater than those tissues from patients of either group I or group II. Tumor superoxide dismutase levels tended to be higher in group II than in group I, although it did not reach a statistical significance.

CONCLUSIONS

Patients with higher superoxide dismutase levels in the hepatocellular carcinoma survived longer after hepatectomy. The superoxide dismutase levels of the tumor tissue may influence the malignancy and the outcome of the patients. It serves as prognostic factor for patients after hepatocellular carcinoma operation.

Expression of the cadherin-catenin complex in well-differentiated human thyroid neoplastic tissue

E-cadherin is a member of the cadherin family that plays a major role in epithelial integrity and tumorigenesis. Catenins are a group of cytoplasmic proteins that regulate the intracellular anchorage of cadherin and are required for the linkage between cadherin and the actin cytoskeleton. Loss of E-cadherin contributes to the pathogenesis in tumor invasion and gives a poor prognosis. In order to investigate the adhesion property of intercellular junctions in thyroid tumors, expression of alpha-,beta, and gamma-catenin should also be studied. A correlation between these molecular markers and malignancy would be useful as a preoperative diagnostic test for thyroid neoplasms. The expression of E-cadherin, alpha-, beta-, and gamma-catenin were studied in normal and neoplastic thyroid tissue by immunofluorescence microscopy and Western blot analysis. In the normal thyroid and in nodular goiter, and follicular adenoma, staining for E-cadherin, alpha-, beta-, and gamma-catenin was seen mainly at the lateral surface of epithelial cells in the follicle and the presence of these molecules was confirmed by Western blot analysis. Follicular carcinoma tissue stained positive for E-cadherin and alpha-catenin, but the results of beta- and gamma-catenin immunostaining were highly variable, with beta-catenin being absent in most follicular carcinomas (8/10) and gamma-catenin being absent in some follicular carcinomas (3/10). These results suggest that E-cadherin expression was not reduced during the pathogenesis of differentiated thyroid malignancies. Impairment of the cadherin-catenin complex at the cell junction may contribute to the malignant progression of differentiated thyroid neoplastic tissue.

Preoperative localization procedures for initial surgery in primary hyperparathyroidism

The experience of the surgeon and precise localization of abnormal parathyroid glands determine the success of surgery for primary hyperparathyroidism (HPT). In HPT patients undergoing repeat surgery, the use of localization studies improved the ability to identify the remaining abnormal parathyroid tissue. This study investigated the roles of preoperative localization techniques for initial surgery for primary HPT. From 1985 through 1997, two noninvasive localization procedures, ultrasonography (US) and 201thallium chloride-99mtechnetium pertechnetate subtraction scanning (Tl-Tc), were used prior to initial exploration for primary HPT in 76 patients. Their accuracy was determined on the basis of surgical and pathologic results. The surgical success rate was 96% (73/76). The sensitivities of US and Tl-Tc were 71% and 49%, respectively. The sensitivity of Tl-Tc was higher for the lower parathyroid glands. In 21 of 26 patients who underwent fine-needle aspiration (FNA) of the suspected enlarged parathyroid gland, the diagnosis of parathyroid adenoma was confirmed preoperatively. We conclude that the concomitant use of US and FNA is a safe and convenient method for preoperative localization of the parathyroid glands prior to initial surgical exploration in patients with primary HPT. Bilateral neck exploration by an experienced surgeon should be the routine procedure. US and Tl-Tc alone offer limited localization information, and unilateral exploration should be reserved for selected cases in which the results of these two imaging studies are consistent with one another.

Distribution of the cadherin-catenin complex in normal human thyroid epithelium and a thyroid carcinoma cell line

E-cadherin is the major cell-cell adhesion molecule expressed by epithelial cells. Cadherins form a complex with three cytoplasmic proteins, alpha-, beta-, and gamma-catenin, and the interaction between them is crucial for anchoring the actin cytoskeleton to the intercellular adherens junctions. The invasive behavior of cancer cells has been attributed to a dysfunction of these molecules. In this study, we examined the distribution of the cadherin-catenin complex in a Chinese human thyroid cancer cell line, CGTH W-2, compared with that in normal human thyroid epithelial cells. In the normal cells, using immunofluorescence staining, E-cadherin and alpha-, beta-, and gammm-catenin were found to be localized at the intercellular junction and appeared as 135, 102, 90, and 80 kD proteins on Western blots. In CGTH W-2 cells, no E-cadherin and gamma-catenin immunoreactivity was detected by immunofluorescence or Western blotting; alpha- and beta-catenin were detected as 102 and 90 kD proteins on blots but gave a diffuse cytoplasmic immunofluorescence staining pattern in most cells, while beta-catenin was also distributed throughout the cytoplasm in most cells but was found at the cell junction in some, where it colocalized with alpha-actinin. The present data indicate that the loss of cell adhesiveness in these cancer cells may be due to incomplete assembly of the cadherin-catenin complex at the cell junction. However, this defect did not affect the linkage of actin bundles to vinculin-enriched intercellular junctions.

Zinc, copper, and superoxide dismutase in hepatocellular carcinoma

Superoxide dismutase (Cu/Zn), a metalloenzyme, activity was found to be significantly lower in the human hepatocellular carcinoma (hepatoma tissue) (0.78 +/- 0.33 U/microg protein) compared with that seen in the surrounding "normal" or cirrhotic tissue (1.40 +/- 0.48 U/microg; 1.27 +/- 0.64 U/microg). The SOD activity of "normal" appearing liver cells adjacent to the tumor or cirrhotic tissue is still lower than that level observed in the normal liver from the subjects without known liver disease (1.40 +/- 0.48 U/microg vs 2.94 +/- 1.53 U/microg). We have also observed that the trace elements of zinc and copper, which are essential in expressing the enzyme activity are also significantly lower in the hepatoma (22.54 +/- 6.73 microg and 2.83 +/- 1.16 microg per gram of tissue) compared with those in the surrounding "normal" hepatic tissue (Zn2+, 64.36 +/- 9.17 microg/g; Cu2+, 11.43 +/- 4.74 microg/g). The difference in the zinc content between the "normal" and the cirrhotic tissue is also significant (64.36 +/- 9.17 microg/g vs 42.37 +/- 10.97 microg/g). However, the copper content in the cirrhotic tissue is higher but not statistically different from that level in the "normal" tissue (15.53 +/- 5.90 microg/g vs 11.43 +/- 4.74 microg/g). Furthermore, the plasma zinc level is significantly lower among the patients who have suffered from hepatoma compared with those subjects without known liver disease (631.73 +/- 52.43 microg/L vs 845.53 +/- 68.13 microg/L). Our data suggest that the superoxide dismutase activity is impaired in the hepatoma tissue. The lower concentration of trace elements (Zn2+ and Cu2+) found in the hepatoma tissue may contribute to cause the difference in the observed enzymic activities.

Factors affecting thyroid function after thyroidectomy for Graves' disease

A series of 108 patients with surgically treated Graves' disease were analyzed retrospectively in an attempt to determine factors that could affect postoperative thyroid function. Univariate analysis showed that remnant size, resected thyroid weight, antithyroid microsomal antibody and antithyroglobulin antibody titers were all significantly related to the postoperative outcome. Remnant size outweighed the other factors in prediction of thyroid status following subtotal thyroidectomy. When all the potential prognostic factors were individually adjusted by remnant size, only the degree of lymphocytic infiltration and antithyroid microsomal antibody titer were significantly associated with the postoperative outcome. Within the range of optimal remnant size, the higher the antithyroid microsomal antibody titer and the degree of lymphocytic infiltration, the greater the likelihood of postoperative hypothyroidism and the lower the chance of recurrence. Further stepwise discriminant analysis revealed that remnant size can be planned according to the known preoperative antithyroid microsomal antibody titer to achieve the greatest likelihood of a postoperative euthyroid state. The model suggested that when the antibody titer is < or = 640, the remnant size should be 3 to 5 cm3; if the antibody titer is 1,280 to 2,560, then the remnant size should be 4 to 5 cm3; and if the antibody titer is > or = 5,120, then the remnant size should be around 5 cm3.

Management of thyroid cancers diagnosed histologically after surgery

Thirty-three patients with thyroid cancer diagnosed histologically after surgery from 1960 to 1987 were reviewed to delineate an acceptable treatment policy. The first group of 17 patients did not undergo a second operation, and five of these patients (29%) experienced local recurrence, metastasis and death during follow-up (minimum of 15 years). A second group of 16 patients underwent a second operation, and all remained healthy during the mean follow-up period of eight years. In 56% of the specimens obtained during the second operation, a histologic examination revealed residual cancerous foci in the remnant thyroid tissue or lymph node. This present study indicates that age, tumor grade, extent and size (AGES score), and the operative strategy used in the initial procedure are important factors affecting the prognosis. We suggest that patients whose tumors lose capsular integrity, show evidence of intraglandular metastases or have an AGES score of 3.1 or more should be considered as candidates for a second operation.

Effect of a taurine-supplemented diet on conjugated bile acids in biliary surgical patients

The effect of a taurine-supplemented diet on the level of conjugated bile acids in postoperative patients was investigated during two consecutive 5-day period. Eighteen hepatobiliary patients with choledochostomies and a specific T-tube insertion were collected and divided randomly into two groups. In group 1, an ordinary postoperative soft diet was prescribed for the first 5 postoperative days and then followed with a taurine-supplemented soft diet (40 mumol/kg per day) for 5 consecutive days. In group 2, the taurine-supplemented diet was prescribed in reverse. At the end of the two periods, on days 5 and 10, bile was collected via a T-tube with an inflatable balloon and low-pressure motor suction. Analysis of conjugated bile acids was done by high-performance liquid chromatography. The results showed that a taurine-supplemented diet increased the concentration of taurocholic acid, glycocholic acid, taurochenodeoxycholic acid, glycochenodeoxycholic acid, and total bile acid from 0.5, 1.9, 0.3, 1.4, and 4.7 mg/mL (on day 5) to 1.1, 3.5, 1.0, 2.6, and 8.9 mg/mL, respectively, on day 10 in group 1. Similar findings were noted in group 2. These results indicate that a taurine-supplemented diet may enhance the conjugation and secretion of bile acid in hepatobiliary patients.

Correlation between sonography and pathology in thyroid diseases

Ultrasonography was performed on the thyroid glands of 47 patients with various thyroid diseases, in a fresh state, immediately following operation. The thyroid glands were then sectioned along the plane of the most significant sonographic changes. The pathologic changes of the sectioned plane were observed and compared with the sonographic changes. In nodular goiter, the sonographic changes were usually heterogeneous. The margin was either well-defined or ill-defined, and cystic changes might play a minor or major part in the thyroid nodules. In follicular adenoma, the changes were isoechoic in adenoma with embryonal type follicles and hyperechoic in adenoma with colloid type follicles. In adenoma of the oxyphilic cells, the echogenicity was somewhat greater in the hemorrhagic part compared to the area with oncocytic change only. In papillary carcinoma, the lesions usually manifested as well-limited, heterogeneous, hypoechoic nodules. Cystic degenerations were frequently noted. There were discrete particles corresponding to microcalcification in 4 out of 6 cases. In follicular carcinoma, the sonographic changes also showed well-limited nodules. However, the echogenicity was not decreased as much as in papillary carcinoma, and it could be either homogeneous and isoechoic, or hypoechoic. Relatively large particles with an acoustic sign, which corresponded to calcification, were noted in 2 out of 4 cases. In medullary carcinoma, the lesion was well-limited and hypoechoic. The particles present in sonography corresponded to calcification in the amyloid. In Graves' disease, the main sonographic change was a diffusely homogeneous, isoechoic or hypoechoic lesion. Cystic change was rarely present. Dispersed particles were rarely present and corresponded to fibrosis in the thyroid tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Subpopulations of intrathyroidal lymphocytes in Graves' disease

Subsets of T- and B-lymphocytes were immunophenotyped in frozen thyroid tissues from 20 patients with Graves' disease by using the avidin-biotin-complex peroxidase method. A panel of B- and T-cell monoclonal antibodies were employed to detect the subsets of T cells, activated T cells, natural killer cells and B cells. Serum thyroglobulin and microsomal antibodies were also measured simultaneously from both the thyroid vein and the peripheral vein in 9 patients. The quantitative results found that an almost equal ratio of lymphocytes stained positively for Leu 3a (CD4) and T8 (CD8) in almost all specimens. Activated lymphocytes expressing T9, T10, and Tac (CD25) were sporadically noted in the interstitial areas. The lymphoid aggregates and follicles were B cell clusters. Natural killer cells appear to play an insignificant role in Graves' disease. The thyroid epithelial cells expressed HLA-DR (Ia+) and HLA-ABC, suggesting a possible localized immune reaction between antigen-presenting thyroid epithelial cells and lymphocytes. The titers of serum thyroglobulin and microsomal antibodies from either the thyroid vein or the peripheral vein showed no definite correlation with the lymphoid distribution of the thyroid tissues, implying that the in situ or local immunologic reaction may not reflect the status of systemic antibody production. The immunologic mechanism and pathogenesis of Graves' disease is reviewed and discussed.

Anaplastic thyroid carcinoma: review of 24 cases, with emphasis on cytodiagnosis and leukocytosis

Twenty-four cases of anaplastic thyroid carcinoma seen in the National Taiwan University Hospital from 1980 to 1988 were reviewed. The median age was 61.5 years. The ratio of men to women was 1:1.4. A preceding history of long-standing goiter could be obtained in 14 patients (58.3%) with a median duration of 20 years. Twenty patients (83.3%) presented with a rapid-growing neck mass with a median duration of 1.3 months. Nine out of 19 patients (47.4%) had white blood cell (WBC) counts over 10,000/microliters, which were closely related to the presence of fever (p less than 0.02). Serial follow-up showed that WBC and platelets gradually increased but red blood cells and hemoglobin decreased. Fever was noted at the time of diagnosis in 8 out of 24 patients (33.3%), and was closely related to the presence of abundant neutrophils in the cytologic smears of thyroid aspirates (p less than 0.01). Fever was not due to bacterial infection. Three out of 10 patients (30.0%) had calcification in the thyroid shown on neck X ray, and 7 out of 18 patients (38.9%) had lung metastasis shown on chest X ray. The ultrasonographic images of thyroid anaplastic carcinoma done in 6 patients were heterogeneous and hypoechoic. Fine-needle aspiration cytology was done in 20 patients. Anaplastic thyroid carcinoma was easily diagnosed in 18 patients (90.0%). One was misdiagnosed as acute thyroiditis. Another one was diagnosed as papillary carcinoma cytologically, which combined with anaplastic carcinoma shown on histology. The median survival was 2.2 months, ranging from 0.2 to 25.3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of injury and total parenteral nutrition on water and electrolytes of RBC, serum, muscle and liver tissue

Trauma is associated with an increased rate of tissue catabolism which can lead to a heightened cellular requirement for regeneration of adenosine triphosphate (ATP) and to decreased activities of adenosine triphosphatases. The effect of severe trauma and total parenteral nutrition (TPN) on water and electrolyte levels in red cells, serum, muscle and liver was investigated. In this study, 16 subjects formed the normal control (control group). The injured group consisted of 8 subjects who suffered from severe trauma and/or post-operative complications with or without infection. The TPN group consisted of 8 subjects in a severe catabolic period who underwent TPN treatment. Blood, muscle and liver samples were obtained during surgical procedures. In red cells and serum, all measured electrolyte levels were within normal limits except the serum of the injured group which showed decreased calcium and increased magnesium levels. Muscle and liver tissue analyses for the injured group showed an increase in water content and sodium and chloride levels, but calcium, potassium and phosphate levels in muscle were decreased. Hepatic potassium and calcium levels, however, were both increased in the same group. In the TPN regimen, cell mass was restored, primarily in muscle, with a contraction of the water content. The restoration of electrolyte levels, especially potassium levels, in muscle during TPN reflected an increase in muscle cell mass.

Cell kinetics, DNA content and TSH receptor-adenylate cyclase system in differentiated thyroid cancer

The purpose of this study was to elucidate the changes of the TSH receptor-adenylate cyclase system in differentiated thyroid carcinomas, and their relationships with nuclear DNA content, cell kinetics and clinical stage. The results showed that the papillary carcinomas had an impaired TSH receptor-adenylate cyclase system. The production of cAMP stimulated by TSH was decreased when compared with non-cancerous tissue and high-affinity TSH receptors were reduced in number or even completely lost (nine in 24 cases). Follicular carcinomas also showed a reduction in, or even complete loss, of high-affinity TSH receptor (one in five cases). However, the responses to the stimulation of TSH, Gpp (NH)p and forskolin were not different from those in non-cancerous tissue. Papillary and follicular cancer cells showed more proliferative activity than those in non-cancerous tissue. Follicular carcinomas contained more hyperploid cells (DNA content greater than 2.5 C) than papillary carcinomas. There were no differences in cell kinetics, DNA content or the effects of Gpp (NH)p or forskolin on adenylate cyclase activity between those papillary carcinomas with high-affinity TSH receptor and those without. However, the presence of high-affinity TSH receptors had higher cAMP generation stimulated by TSH. The patients having papillary carcinomas in the absence of high-affinity TSH receptors were all in clinical stage III. These studies suggest that TSH receptors are the major sites influenced in the TSH receptor-adenylate cyclase system in papillary carcinomas. The TSH receptor-adenylate cyclase system of papillary carcinomas differs more from normal than does that of follicular carcinomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of severe injury and critical illness on high-energy phosphates in human liver and muscle

Changes in hepatic and muscle high-energy phosphates in varying degrees of resting hypermetabolism were studied. Fourteen severely injured and five critically ill patients with normal blood pressure were investigated: the results were compared with 14 normal controls. ATP and ADP levels in the muscle were significantly changed in acutely severe injury: lactate and pyruvate levels in the liver and muscle increased; glycogen level in the liver decreased. Meanwhile, high-energy phosphates in both liver and muscle were not significantly changed in ongoing severe injury. Lactate level increased and glycogen level decreased in both tissues. In critical illness, hepatic and muscle ATP and ADP decreased significantly. The energy charge potential dropped. AMP, lactate, and the lactate-to-pyruvate ratio increased. Hepatic, but not muscle, glycogen dropped markedly. The correlation coefficient between hepatic and muscle ATP was 0.61; between hepatic ATP and hepatic glycogen was 0.60. Alteration in the ATP-ADP-AMP system in the liver and muscle suggests a low-energy charge in acute, severe injury and critical illness. This indicates a decreased capacity for biosynthetic reactions and production of storage compounds. The changes in high-energy phosphate in the liver always paralleled similar changes in muscle.

Effect of injury, sepsis, and parenteral nutrition on high-energy phosphates in human liver and muscle

This study examined the effect of varying degrees of resting hypermetabolism and total parenteral nutrition on muscle and hepatic high-energy phosphates. Twelve severely injured patients, five critically ill patients with normal blood pressure, and six severely ill patients on 1 wk of total parenteral nutrition were investigated, and the results were compared with those in 14 normal controls. High-energy phosphates were not significantly changed in liver and muscle after severe injury; lactate and pyruvate levels in both tissues were increased; glycogen levels in the liver were decreased. In critical illness, muscle and hepatic adenosine triphosphate as well as adenosine diphosphate were decreased significantly; energy charge potential dropped; adenosine monophosphate, lactate, and the ratio of lactate to pyruvate were increased. Liver glycogen, but not muscle glycogen, dropped remarkably. The correlation coefficient between hepatic and muscle adenosine triphosphate was 0.61. In patients on 1 wk of total parenteral nutrition, hepatic and muscle high-energy phosphates were not significantly changed before or during total parenteral nutrition. Alterations in the adenosine triphosphate-adenosine diphosphate-adenosine monophosphate system in liver and muscle suggest a low-energy charge in severe injury and critical illness. This would indicate a decreased capacity for biosynthetic reactions and production of storage compounds. The changes of high-energy phosphates in liver are always parallel to changes in muscle.

Effect of postoperative nutrition on muscle high energy phosphates

This study examines the effect of hypocaloric nutritional regimens on muscle high energy phosphates in normal subjects and patients following total hip replacement. Eighteen patients undergoing total hip replacement and 11 normal subjects on a four-day period of bedrest were studied. The patients were randomly assigned to receive either: (1) 90 gms/day glucose; (2) 70 gms/day amino acids; or (3) 90 gms/day glucose + 70 gms/day amino acids. A percutaneous muscle biopsy was performed before operation and on the morning of the fourth day after operation. Samples were analyzed for adenine triphosphate (ATP), adenine diphosphate (ADP), adenine monophosphate (AMP), phosphocreatine (PC), free creatine (CR), lactate, and pyruvate. Normal subjects were assigned to receive either: (1) 90 gms/day glucose; (2) 70 gms/day amino acids; or (3) no caloric intake. The patients receiving amino acid alone demonstrated a decrease in ATP, ADP, and PC, while AMP and free creatine rose. No significant changes were seen in patients who received 90 gms/day glucose either with, or without, amino acids. There were also no significant changes in any of the normal subjects. These results suggest that a series of metabolic changes occur in skeletal muscle following injury such that small amounts of glucose are important for maintenance of cellular energy levels.

Effect of injury and sepsis on high-energy phosphates in muscle and red cells

Changes in muscle high-energy phosphates in varying degrees of resting hypermetabolism were studied. Eleven patients were investigated before and 4 days after total hip replacement. The postoperative results were compared with those seen in major traumas and sepsis. High-energy phosphates were not significantly changed in muscle after total hip replacement or moderate injury; muscle lactate and pyruvate increased. Increased degrees of hypermetabolism such as severe trauma and sepsis were associated with reduction of muscle ATP and PC; AMP, free CR, lactate, and pyruvate rose. Simultaneously determined levels of high-energy phosphates in red blood cells did not reflect muscle changes, confirming the need for continued direct tissue measurements. Alterations in the ATP--ADP--AMP system in the muscle cell suggest a low-energy charge following severe trauma especially if accompanied by sepsis. This would indicate a decreased capcity for biosynthetic reactions and production of storage compounds. Tissue high-energy phosphates and cellular energy levels thus may be the cellular expression of the catabolic state.

Impaired cell-mediated immunity function in thyroid cancer

Immunological parameters were studied in 31 patients with thyroid cancer. Serum immunoglobulin levels, T and B cell percentages in peripheral blood, showed no significant difference as compared with those of control group. The blastogenesis with phytohemagglutinin P (PHA) was significantly reduced, especially, in those having larger tumor size or metastasis or in those over age 60. The positive rate of skin test with purified-protein-derivative (PPD) and Streptokinase-Streptodornase (SK-SD) was also markedly reduced. The impaired blastogenesis of lymphocyte and reduced positive rate of skin test in those cancer patients suggested that the cell-mediated immunity function, in spite of adequate count of T-cells, was impaired.

Thyroid cancer after irradiation

Nine patients with thyroid cancer who had received irradiation on the thyroid region (four for breast cancer with deep x-ray or Co60, one for a skin lesion with deep x-ray and four for hyperthyroidism with I131) have been discussed. These cases might be within the range of statistical coicidence, but the potential carcinogenic effect of irradiation could not be ruled out completely. The need for detailed examination of the thyroid gland before and for many years after irradiation and early removal of thyroid gland nodules which develop after I131 treatment are emphasized.