Subserosal Layer and/or Pancreatic Invasion Based on Anatomical Features as a Novel Prognostic Indicator in Patients with Distal Cholangiocarcinoma

The American Joint Committee on Cancer (AJCC) 8th edition T-staging system for distal cholangiocarcinoma (DCC) proposes classification according to the depth of invasion (DOI); nevertheless, DOI measurement is complex and irreproducible. This study focused on the fibromuscular layer and evaluated whether the presence or absence of penetrating fibromuscular invasion of DCC contributes to recurrence and prognosis. In total, 55 patients pathologically diagnosed with DCC who underwent surgical resection from 2002 to 2022 were clinicopathologically examined. Subserosal layer and/or pancreatic (SS/Panc) invasion, defined as penetration of the fibromuscular layer and invasion of the subserosal layer or pancreas by the cancer, was assessed with other clinicopathological prognostic factors to investigate recurrence and prognostic factors. According to the AJCC 8th edition, there were 11 T1, 28 T2, and 16 T3 cases, with 44 (80%) cases of SS/Panc invasion. The DOI was not significantly different for both recurrence and prognostic factors. In the multivariate analysis, only SS/Panc was identified as an independent factor for prognosis (hazard ratio: 16.1; 95% confidence interval: 2.1-118.8, p = 0.006). In conclusion, while the determination of DOI in DCC does not accurately reflect recurrence and prognosis, the presence of SS/Panc invasion may contribute to the T-staging system.

Endovascular treatment of postoperative hemorrhage after pancreatectomy: a retrospective study

BACKGROUND

Ruptured aneurysm is a serious complication of distal pancreatectomy (DP) or pancreatoduodenectomy (PD) that can be life-threatening if not treated promptly. This study aimed to examine the efficacy of a Viabahn stent graft for stopping bleeding after pancreatectomy.

METHODS

Between April 2016 and June 2022, we performed 245 pancreatectomies in our institution. Six patients experienced postoperative bleeding and underwent endovascular treatment.

RESULTS

All six cases of bleeding occurred post-PD (3.7%). The bleeding was from gastroduodenal artery (GDA) pseudoaneurysms in three patients, and Viabahn stent grafts were inserted. All three patients did not show liver function abnormalities or hepatic blood flow disorders. One patient with a Viabahn stent graft experienced rebleeding, which required further management to obtain hemostasis. Of the six cases in which there was hemorrhage, one case of bleeding from the native hepatic artery could not be managed.

CONCLUSIONS

Using the Viabahn stent graft is an effective treatment option for postoperative bleeding from GDA pseudoaneurysms following PD. In most cases, using this device resulted in successful hemostasis, without observed abnormalities in hepatic function or blood flow.

Factors contributing to nonalcoholic fatty liver disease (NAFLD) and fat deposition after pancreaticoduodenectomy: A retrospective analysis

Aim

Nonalcoholic fatty liver disease (NAFLD) can occur due to various reasons after pancreaticoduodenectomy (PD). This study examined the risk and perioperative determinants of NAFLD and fat deposition after PD.

Methods

A total of 101 patients who had undergone computed tomography 6 months after PD were included. We compared perioperative factors between patients who developed NAFLD and those who developed fatty deposits after PD.

Results

In the NAFLD group, pancreatic cancer was significantly more prevalent among patients who developed postoperative NAFLD (p = 0.024) and had a lower postoperative body mass index (BMI; p = 0.008). Multivariate analysis revealed that pancreatic carcinoma (hazard ratio [HR] 4.42, 95% confidence interval [CI] 1.118-17.442, p = 0.034) and lower postoperative BMI (HR 0.51, 95% CI 0.274-0.954, p = 0.0355) were risk factors for fatty liver. Pancreatic leakage (p = 0.024) and postoperative BMI (p = 0.002) were significantly lower in the fat deposition group than those in the NAFLD group. Multivariate analysis also revealed that a lower postoperative BMI was a risk factor for fat deposition (HR 0.56, 95% CI 0.523-0.982, p = 0.042). Moreover, multivariate analysis revealed that the fat deposition group had significantly lower pancreatic leakage than the NAFLD group (HR 7.944, 95% CI 1.993-63.562, p = 0.049).

Conclusion

The findings of this study suggest that postoperative BMI and pancreatic cancer are associated with a higher risk of NAFLD after PD, possibly because of pancreatic exocrine insufficiency and impaired fat absorption.

Lung metastases from intraductal papillary neoplasm of the bile duct: a case report

Background

Intraductal papillary neoplasm of the bile duct (IPNB) is considered a pre-cancerous biliary lesion and/or an early cancer lesion, although its classification remains unclear. The 2019 revised edition of the World Health Organization Classification of Tumors of the Digestive System proposed type 1 and type 2 as new classification categories, and meta-analyses and/or multi-center cohort studies are beginning to be reported. However, treatment for IPNB recurrence and metastasis remains unclear.

Case presentation

A 60-year-old man who was referred to our hospital after a suspected liver tumor was diagnosed using abdominal ultrasonography. Imaging findings revealed an irregularly shaped tumor in segment 5 (S5) of the liver (size 20 mm). The S5 lesion was suspected as IPNB, and segmentectomy was performed. The pathological findings revealed invasive carcinoma derived from IPNB, and immunohistochemistry revealed positive expression of MUC1, MUC5AC, and MUC6, but negative expression of CDX2 and MUC2. At 9 months after the surgery, computed tomography revealed a tumor in the right bile duct, which was diagnosed as liver recurrence of IPNB, and right hepatectomy was performed. The histopathological findings were the same as for the first resected specimen (i.e., IPNB). At 45 months after the second surgery, computed tomography revealed nodules in both lungs, which were diagnosed as lung metastases from IPNB and resected in two separate procedures. The pathological findings were metastatic carcinoma from IPNB for both lung lesions. The patient is currently alive and undergoing adjuvant chemotherapy (S-1), which was initiated 64 months after the first resection and 12 months after resection of the lung metastases.

Conclusion

We encountered a rare case of lung metastases from IPNB, which were diagnosed immunohistologically. Because IPNB is generally a slow-growing tumor, resection may be feasible for IPNB recurrence and/or metastasis, which may be detected during long-term follow-up. Thus, even if resection is performed for primary IPNB, additional surgical treatment may be feasible in this setting.

P0668UNILATERAL URETER OBSTRUCTION (UUO)-INDUCED RENAL FIBROSIS IS ATTENUATED BY SUPPRESSION OF INDOXYL SULFATE (IS) ACCUMULATION IN SULFOTRANSFERASE (SULT)1A1-DEFICIENT MICE

Background and Aims

Obstructive nephropathy is the result of functional or anatomic lesions located in the urinary tract, and renal interstitial fibrosis is a common finding associated with long-term nephropathy. Many factors are suggested to be involved in the pathogenesis of renal fibrosis, such as infiltration of macrophages, growth factors, oxidative stress and cytokines. Indoxyl sulfate (IS), a typical sulfate-conjugated uremic solute, accumulates markedly in serum and renal tissue of cisplatin- or ischemia/reperfusion-induced acute kidney injury model animals, thereby inducing generation of oxidative stress. However, the relationship between IS and obstructive nephropathy or renal fibrosis remains unclear. IS is produced in the liver by CYP2A6/2E1-dependent oxidative metabolism of dietary protein-derived indole, followed by sulfotransferase 1a1 (SULT1A1)-mediated sulfate conjugation of indoxyl. IS in the blood circulation is efficiently taken up by renal proximal tubules via basolateral membrane-localized organic anion transporters, OAT1 and OAT3, and excreted into urine via unidentified apical membrane-located transporter. Thus, we established SULT1A1 gene-deficient (SULTKO) mice and developed UUO mice to investigate the pathological role of IS in UUO-induced renal fibrosis.

Method

The left ureter of C57BL/6J mice (wild type (WT), 8 weeks-old) and SULTKO mice (8 weeks-old) were obstructed last for 2 weeks. IS concentration in serum and kidney was determined by LC-MS/MS. Changes in histology and interstitial fibrosis were examined with PAS staining and Sirius red staining, respectively. Quantitative PCR was applied for determining expression levels of col1a1 encoding the major component of type I collagen, fibronectin, plasminogen activator inhibitor (PAI)-1, the activator of plasminogen and hence fibrinolysis, pro-inflammatory cytokine interleukin 6 (IL-6), Wnt4 encoding one protein of Wnt and Sfrp5, a gene that codes for antagonist of Wnt pathway. Renal fibrosis also evaluated through the expression of alpha smooth muscle actin (SMA) by Western blotting.

Results

By UUO treatment, the concentration of IS in serum, kidney and liver were elevated, which were suppressed in SULTKO mice. Ureter dilation was obviously observed in the obstructed kidney of WT mice, which was slightly prevented in SULTKO mice with UUO. Sirius red staining revealed that severe collagen deposition was found in the interstitium of WT kidney with UUO, but it was partly prevented in the kidney of KO mice with UUO along with the decrease in IS accumulation. The high expression of SMA, col1a1 and fibronectin in the kidney of WT mice with UUO were significantly suppressed in the kidney of SULTKO mice, 2.3-fold, 1.4-fold and 2.3-fold, respectively, suggesting that renal fibrotic responses were ameliorated in SULTKO mice. The expression of PAI-1, which was upregulated in WT mice with UUO, was also suppressed (1.8-fold) in SULTKO mice with UUO. The elevated expression of IL-6 in the kidney of WT mice with UUO was inhibited (1.8-fold) in SULTKO mice with UUO, indicating the possibility that inflammation-related signalling pathway also participated in the IS-exacerbated renal fibrosis. The enhanced expression of Wnt4 in the kidney of WT mice with UUO was suppressed (1.8-fold) in SULTKO mice with UUO, and the gene of Sfrp5 exhibited a higher expression level (3.2-fold) in the kidney of SULTKO mice with UUO compared with WT UUO mice.

Conclusion

Sult1a1-deficient mice showed the suppressed accumulation of IS in the kidney with UUO. Renal IS accumulation during pathological progression of obstructive nephropathy could enhance interstitial fibrosis through the activation of Wnt signalling pathway. Hepatic SULT1A1 could be a therapeutic target for preventing the progression of renal interstitial fibrosis by suppressing IS production during obstructive nephropathy.

Role of blood ribosomal protein S19 in coagulum resorption: a study using Gln137Glu-ribosomal protein S19 gene knock-in mouse

Sera of human, guinea pig or mouse contain a strong monocyte chemoattractant capacity that is attributed to the ribosomal protein S19 (RP S19) oligomers generated during blood coagulation. In contrast, sera prepared from Gln137Glu-RP S19 gene knock-in mice contained negligible chemoattractant capacity. When coagula that had been pre-formed from the blood of both the wild type and knock-in mice were intraperitoneally inserted into host mice, after 3 days of recovery, the knock-in mouse coagula remained larger than the wild type mouse coagula. The wild type mouse coagula were covered by multiple macrophage layers at the surface and were infiltrated inside by macrophages. Knock-in mouse coagula exhibited less macrophage involvement. When coagula of knock-in mice and coagula of knock-in mice containing C5a/RP S19, an artificial substitute of the RP S19 oligomers, were intraperitoneally inserted as pairs, the C5a/RP S19 containing coagulum was more rapidly absorbed, concomitant with increased macrophage involvement. Finally, when the knock-in mouse and wild type mouse coagula pairs were inserted into mice in which macrophages had been depleted using clodronate liposome, the size difference of recovered coagula was reversed. These results indicate the importance of the RP S19 oligomer-induced macrophage recruitment in coagulum resorption.

Weight lifting can facilitate appreciative comprehension for museum exhibits

Appreciation of exhibits in a museum can be equated to a virtual experience of lives in the contexts originally surrounding the exhibits. Here we focus on the importance of weight information, and hence tested whether experiencing a weight during museum exhibit appreciation affects the beholders' satisfaction and recognition memory for the exhibits. An experiment was performed at a museum exhibiting skeletal preparations of animals. We used nine preparations and prepared four weight stimuli as weight cues in accordance with the actual weight of four of the preparations: Remaining five preparations was displayed without weight stimuli. In the cued condition, participants were asked to lift up the weight stimuli during their observation of the four exhibits. In the uncued condition, participants observed the exhibits without touching the weight stimuli. After observation of the exhibits, the participants responded to a questionnaire that measured their impressions of the exhibits and the museum, and performed a recognition test on the exhibits. Results showed that memory performance was better and viewing duration was longer with weight lifting instruction than without instruction. A factor analysis on the questionnaires revealed four factors (likeability, contentment, value, and quality). A path analysis showed indirect effects of viewing duration on memory performance and willingness-to-pay (WTP) for the museum appreciation through the impression factors. Our findings provide insight into a new interactive exhibition that enables long appreciation producing positive effects on visitors' impression, memory, and value estimation for exhibits.

Gelatin beads as platforms for targeting molecule and anti-Fas antibody: two major properties of cytotoxic T lymphocytes

OBJECTIVE

Cytotoxic T lymphocytes (CTL) initially recognize target cells using the T-cell receptor (TCR), then strongly adhere to these cells by accessory molecules, and finally induce apoptosis by Fas ligand (FasL)/Fas or lyse by the granzyme/perforin system. We describe the development of gelatin beads carrying anti-tumor monoclonal antibody (mAb) and anti-Fas mAb mimicking the TCR and FasL, respectively. We hypothesized that these antibody-coated beads can be therapeutically utilized for the elimination of tumor cells.

MATERIALS AND METHODS

We evaluated the cytotoxic activity of gelatin beads bearing CH11 (anti-Fas mAb) after incubation with several human leukemia cell lines. Cytotoxic activities were measured using colorimetric DNA fragmentation assay and lactate dehydrogenase (LDH) release assay.

RESULTS

We demonstrated that the cytotoxic effects of anti-Fas mAb were markedly enhanced by fixation on gelatin beads. Microscopic examination showed that the beads attached to the target cells and induced their apoptosis. These effects were enhanced further by adding tumor-specific mAb. These in vitro properties of the beads were well reconstituted in the peritoneal cavity of mice.

CONCLUSION

Although antibody-coated gelatin beads lack several important properties of natural CTL, such as differentiation, proliferation, and the functions of adhesion molecules, they mimic well the targeting and cytotoxic functions of natural CTL. Our findings suggest that antibody-carrying gelatin beads may be the first step toward the development of artificial CTL and can be applied, for example, to artificial dendritic and stroma cells for the development of novel biotherapeutic approaches.

[Case of stage IVb gastric cancer in which favorable anti-tumor effect and good QOL were observed due to UFTP therapy after low-dose CDDP-tegafur therapy]

A patient with stage IVb advanced gastric cancer, who was Group 4 lymph node metastasis positive, underwent two postoperative courses of low-dose CDDP-tegafur therapy (800 mg/body/day of tegafur + 5 mg/body/5 administrations, 2 days of rest, of cisplatin). UFTP therapy (400 mg/body/day of UFT + 5 mg/body/twice weekly of cisplatin) was thereafter given on an outpatient basis. The patient has now been receiving this therapy for one year and six months. The anti-tumor effect has been maintained and the tumor has been reduced in size by 89% without any adverse reactions. A good QOL has been observed. The present therapy can be performed safely at home and appears to be a favorable treatment from the viewpoint of QOL.

Development of a gelatin particle agglutination reagent for measles antibody assay

A new agglutination test that utilizes gelatin particles as the carrier of measles antigen was developed and used to evaluate immune status to measles virus infection. The particle agglutination (PA) reagent reacted with monoclonal antibodies against two major proteins of measles virus, the hemagglutinin (H) and fusion (F) proteins. Children were followed individually for ten years for measles antibody. Results showed that the PA test was as sensitive and specific as the plaque neutralization test. The procedure is simple and rapid. No prior treatment of specimens is needed, and the test is completed in a single reaction. The PA test therefore can be used for diagnoses and epidemiologic surveys of measles virus infection.

Development and usefulness of the gelatin-particle-agglutination test for titration of antibodies against diphtheria, pertussis and tetanus toxins

The gelatin-particle-agglutination (PA) test for titrating antibodies against diphtheria, pertussis and tetanus toxins was developed and used for assaying 65 sera from healthy children to assess the antitoxin acquisition in relation to the administration of adsorbed diphtheria-purified pertussis-tetanus (DPT) combined vaccine. The antitoxin titers obtained by the PA test and the conventional methods were correlated well; the correlation coefficient of the diphtheria antitoxin titers between the PA test and the cell culture method was 0.908, that of the tetanus antitoxin titers between the PA test and the passive hemagglutination test 0.968, and that of anti-pertussis toxin titers between the PA test and polystyrene-ball ELISA 0.885. The PA test was shown to be useful in both developed and developing countries, since it is simple to perform, sensitive and specific, and the three antitoxins can be titrated by the same procedure.

A novel magnetic particle agglutination in microtiter plates for rapid detection of human T-lymphotropic virus type I antibody

We have developed a novel magnetic particle agglutination (MPA) method for rapid detection of antibody to human T-lymphotropic virus type I (HTLV-I). This method is suitable for screening determination. The assay uses purified viral antigen coated on magnetic particles, which are novel artificial particles made of gelatin, arabic gum, and ferrite. MPA uses a special magnet and inclined plate holder. In MPA, the specimen is incubated with magnetic particles in the well; magnetic particles are then magnetically attracted to the bottom of the well. Then the plate is inclined and read by the naked eye. In a positive specimen, agglutination particles stay at the bottom of the well. On the other hand, non-agglutination particles with negative sample run down the side of the well. The total assay time of MPA was estimated at 8 min/microtiter-plate. The results obtained by correlating MPA for the detection of HTLV-I antibody with other method emphasized the precision of MPA.

Improvement of simultaneous detection of antibodies to Gag and envelope antigens of human T-lymphotropic virus type I by western immunoblot assay

To determine seropositivity for human T-lymphotropic virus type I (HTLV-I), we attempted to improve the detection system that uses antibody to HTLV-I Env in Western immunoblotting (WB) by adding an envelope glycoprotein (gp46) purified from the culture fluid of HTLV-I-producing cells by immunoaffinity chromatography and gel chromatography. In this WB, 177 of 179 serum samples showing seropositivity in an indirect immunofluorescence assay showed positive reactions to the gp46 envelope antigen as well as to p19, p24, and p53 Gag antigens. The remaining two samples showed negative reactions to p24. False-positive results were not found for 533 indirect immunofluorescence assay-negative serum samples, although one band to p19 or p24 was observed in 46 of the 533 samples. These 46 samples did not react to p53 and gp46, suggesting that these samples belonged to the indeterminate group in accordance with the criteria proposed by the World Health Organization. Therefore, this improved WB can be used for the confirmation of seropositivity.

Improvement of gelatin particle agglutination test for detection of anti-HTLV-I antibody

Partial modifications of antigen components were made to improve the gelatin particle agglutination (PA) test for the detection of antibodies against human T cell leukemia virus type-I. Envelope glycoproteins prepared by lentil lectin affinity chromatography were further added to the purified viral antigens to be coated on the gelatin particles. Comparative studies with a conventional PA test kit (Serodia ATLA) and indirect immunofluorescence assay showed that the specificity and sensitivity of the new PA test were increased and that abnormal agglutination such as the prozone phenomenon was abolished by this improvement.

[Clinical observations with cefteram pivoxil granules in field of pediatrics]

A new oral cephem antibiotic, cefteram pivoxil (CFTM-PI, T-2588), was studied for clinical efficacy in the field of pediatrics. CFTM-PI was given orally to 23 patients with the following acute bacterial infections: 6 cases of acute tonsillitis, 8 of acute bronchitis, 2 of scarlet fever, 4 of bronchopneumonia, 1 of acute otitis media with sinusitis and 2 of urinary tract infections. Clinical results were "excellent" in 8, "good" in 14, "poor" in 1: the efficacy rate was 95.7%. As an adverse reaction, diarrhea was observed in 1 patient. From the above clinical results, it appears that CFTM-PI is a useful antibiotic for the treatment of pediatric patients with various bacterial infections.

Patterns of migration indicate sexual transmission of HTLV-I infection in non-pregnant women in Papua New Guinea

The prevalence of infection with human T-cell leukaemia virus (HTLV-I) was studied in Madang Province on the north coast of Papua New Guinea. Serum specimens collected from non-pregnant women in 17 villages were tested for anti-HTLV-I by gelatin particle agglutination screening and confirmed by immunofluorescence and Western blotting. Overall, 13.9% of subjects were antibody-positive, with the prevalence of antibodies varying from less than 10% to 30% in villages situated less than 10 km apart. Two groups of migrant women were identified, and in both a parity-related increase in antibody prevalence which occurred only after marriage suggested that the predominant mode of transmission in migrant women was sexual. There was no parity-associated increase in anti-HTLV-I in indigenous women, and in contrast to migrant women, nulliparous indigenous women had a high prevalence of antibody (16.8% vs. 0%; p = 0.005). Vertical transmission cannot be excluded in indigenous women. No correlation was detected between the prevalence of anti-HTLV-I and a variety of indices of malarial infection.

Alteration in activities of Na,K, ATPase, sugar transport, and insulin receptors in erythrocytes from hyperthyroid patients

To investigate the selectivity of the reduction in Na,K, ATPase activity in erythrocytes from patients with hyperthyroidism, we have assessed cytochalasin B-sensitive galactose uptake and insulin receptors as well as Na,K, ATPase-mediated rubidium uptake in erythrocytes from 11 patients with hyperthyroidism, 5 patients after treatment and 11 normal controls. There was a significant reduction in the Vmax values for rubidium uptake and the number of insulin receptors (23% and 20% below control, respectively), whereas there was a significant increase in the Vmax and Km values for galactose uptake (49% and 30% above control) and also in the average affinity of insulin receptors. The alterations both in rubidium and galactose transport activities were reversible with effective treatment of hyperthyroidism. The magnitude of alterations in the Vmax for rubidium uptake correlated inversely (r = -0.537 P less than 0.01, n = 16) and the Vmax and Km for galactose uptake correlated positively (r = 0.597 P less than 0.02 and r = 0.553 P less than 0.05, respectively) with serum T4 level. No correlation was found between the number of insulin receptors and serum IRI or T4 levels. These results suggest that the reduction in Na,K, ATPase activity observed in erythrocytes from hyperthyroid patients is not selective to this enzyme, but rather a reflection of widespread alterations of erythrocyte cell-surface proteins.

A new agglutination test for serum antibodies to adult T-cell leukemia virus

A new gelatin particle agglutination test was developed for assay of natural antibodies to adult T-cell leukemia virus (ATLV/HTLV-I). Partially purified viral antigen from culture fluid of a virus-producer cell line was coated on artificial gelatin particle carriers. A high correlation was observed between the titers of antibodies determined by the agglutination test and by indirect immunofluorescence assay. The agglutination test is simple, sensitive and specific, and should be useful for mass screening of human sera for viral antibodies.

[A case of extramedullary plasmacytoma of the stomach]

A 51-year-old man with extramedullary plasmacytoma of the stomach is presented. He complained of epigastralgia. Barium meal revealed 2 submucosal tumors in the gastric body. Laboratory investigations showed neither hypergammaglobulinemia nor proteinuria. Bone X-ray examinations were not remarkable. There was tumor invasion to the pancreas and metastasis to the perigastric lymph nodes. Proximal gastrectomy was performed, and the patient died 5.5 years after the operation. Histologically, the proliferation of atypical plasma cells with eccentric nuclei was seen. Those cells invaded all layers of the stomach. The tumor cells were pyroninophilic and contained Russel bodies. Immunohistochemical study using the immunoperoxidase technique demonstrated IgG and lambda-light chains in the tumor cells.

[Changes in responsivity to TRH test and T3-suppression test after surgical treatment of hyperthyroidism (author's transl)]

TRH test and T3 suppression test were performed on patients with Graves' disease who underwent subtotal thyroidectomy after treatment with antithyroid drugs for 2.5 approximately 5 months. On 43 or the patients, TRH test was performed before, 1 week after and 1 approximately 2 months after surgery and T3 suppression test was also performed in 1 approximately 2 months post-operative period. For other 3 groups of the patients TRH test was performed at 2 approximatley 6 months, 6 approximately 12 months, 12 approximately 24 months and 24 approximately 41 months after surgery, and T3 suppression test was also performed just after each TRH test. As to TRH test, the response was defined as positive when basal TSH value was less than 2.0 muU/ml and peak value was more than 6.2 muU/ml or the difference between basal TSH and peak TSH value was over 5 muU/ml following TRH (500 mug) injection. T3 suppression test was perfomed by measuring the 24-hr thyroidal uptake of radioiodine after daily administration of 75 mug of T3 for 8 days. The response was defined as positive when the value for 24-hr uptake after T3 administration was less than half of the control value. The results were as follows; (1) In 11 of 43 patients, response to TRH test already changed to positive 1 week after operation and in 21 of 43 patients TRH test changes to positive 1 approximately 2 months after operation. (2) In general, response to TRH test changed to positive earlier than response to T3 suppression test. (3) T3 suppression test in 1 approximately 2 months after operation was useful to evaluate prognosis. (4) A half of the positive respondents to TRH test showed exaggerated response. (5) Basal TSH value of positive respondents to TRH test was 9.27 +/- 1.81 muU/ml (mean +/- SE) which exceeded the normal range. (6) Some patients showed negative response to conventional T3 suppression test despite of their high basal TSH value. This might be due to the insufficient dose of T3 to suppress TSH. (7) Concerning patients whose serum T3-RU, T4, T3 and TSH were within normal limit after subtotal thyroidectomy, 80% of them showed correspondance in the results of TRH test and T3 suppression test.