Favourable surgical outcomes for either second primary lung cancer or intrapulmonary metastasis after resection of non-small-cell lung cancer

OBJECTIVES

Metachronous lung cancer arising after resection of non-small-cell lung cancer is either a second primary lung cancer (SPLC) or intrapulmonary metastasis (IPM) of the initial lung cancer; however, differential diagnosis is difficult. We evaluated the surgical outcomes of metachronous lung cancer in a combined population of patients with SPLC and IPM.

METHODS

A retrospective study of 3534 consecutive patients with resected non-small-cell lung cancer between 1992 and 2016 was conducted at 4 institutions.

RESULTS

A total of 105 patients (66 males; median age, 70 years) who underwent a second pulmonary resection for metachronous lung cancer were included. Most patients (81%) underwent sublobar resection, and there was no 30-day mortality. All metachronous lung cancers were cN0, 5 were pN1-2. The postoperative comprehensive histologic assessment revealed SPLC (n = 77) and IPM (n = 28). The 5-year overall survival rate after the second resection was 70.6% (median follow-up: 69.7 months). A multivariable analysis showed that age >70 years at the second resection (P = 0.013), male sex (P = 0.003), lymph node involvement in metachronous cancer (P < 0.001), pathological invasive size of metachronous cancer >15 mm (P < 0.001) and overlapping squamous cell carcinoma histology of the initial and metachronous cancers (P = 0.003) were significant prognostic factors for poor survival after the second resection, whereas histological IPM was not (P = 0.065).

CONCLUSIONS

Surgery for cN0 metachronous lung cancer is safe and shows good outcomes. There were no statistically significant differences in the SPLC and IPM results. Caution should be exercised when operating on patients with overlapping squamous cell carcinoma.

Effect of Recent Antirheumatic Drug on Features of Rheumatoid Arthritis-Associated Lymphoproliferative Disorders

OBJECTIVE

In this study, we examine how advancements in novel antirheumatic drugs affect the clinicopathologic features of lymphoproliferative disorder (LPD) in patients with rheumatoid arthritis (RA).

METHODS

In this multicenter study across 53 hospitals in Japan, we characterized patients with RA who developed LPDs and visited the hospitals between January 1999 and March 2021. The statistical tools used included Fisher's exact test, the Mann-Whitney U-test, the log-rank test, logistic regression analysis, and Cox proportional hazards models.

RESULTS

Overall, 752 patients with RA-associated LPD (RA-LPD) and 770 with sporadic LPD were included in the study. We observed significant differences in the clinicopathologic features between patients with RA-LPD and those with sporadic LPD. Histopathological analysis revealed a high frequency of LPD-associated immunosuppressive conditions. Furthermore, patients with RA-LPD were evaluated based on the antirheumatic drugs administered. The methotrexate (MTX) plus tacrolimus and MTX plus tumor necrosis factor inhibitor (TNFi) groups had different affected site frequencies and histologic subtypes than the MTX-only group. Moreover, MTX and TNFi may synergistically affect susceptibility to Epstein-Barr virus infection. In case of antirheumatic drugs administered after LPD onset, tocilizumab (TCZ)-only therapy was associated with lower frequency of regrowth after spontaneous regression than other regimens.

CONCLUSION

Antirheumatic drugs administered before LPD onset may influence the clinicopathologic features of RA-LPD, with patterns changing over time. Furthermore, TCZ-only regimens are recommended after LPD onset.

Breast carcinoma with spontaneous regression after needle biopsy: a case report and literature review

Background

Spontaneous regression (SR) of cancer is a rare condition in which the cancer partially or completely disappears without treatment. We report a case of breast cancer with tumor regression and spontaneously induced T-cell-mediated immunological responses in a surgical specimen obtained after core needle biopsy (CNB).

Case Description

A 52-year-old woman presented with a mass in the right breast. Mammography showed a high-density mass with fine serrated margins in the right lower outer quadrant. Breast ultrasonography showed an irregular hypoechoic mass with a maximum diameter of 22 mm. CNB was performed and revealed an invasive ductal carcinoma with negative estrogen receptors, positive progesterone receptors, and negative HER2 (1+). The Ki67 index was 70% to 80%. Luminal B cT2N1M0 stage IIB right breast cancer was diagnosed. Although preoperative chemotherapy was considered, surgery was selected because of her history of schizophrenia. She underwent right mastectomy and axillary lymph node dissection. A postoperative pathological analysis revealed a 20 mm × 10 mm × 10 mm mass. However, most areas of the mass regressed and appeared as necrotic tissue with no obvious invasive areas. Only intraductal extension was observed in one glandular duct. Axillary lymph node metastases were not observed. These results suggest that the tumor may have spontaneously regressed, possibly because of the CNB procedure. Follow-up without treatment was performed, and no recurrence occurred during 2 years after surgery.

Conclusions

Invasive ductal carcinoma may spontaneously regress after preoperative CNB.

[A Case of Laparoscopic Total Gastrectomy for Juvenile Polyposis of Stomach with Synchronous Multiple Intramucosal Carcinomas]

The patient was a 57-year-old woman. She was referred to our hospital because severe anemia. Upper gastrointestinal endoscopy revealed polyposis throughout the stomach and lobulated polyps in cardia, greater curve of middle body of the stomach, and angulus. Colonoscopy and small bowel endoscopy showed no obvious abnormal findings. Based on these findings, a laparoscopic total gastrectomy with D1 lymph node dissection was performed for suspected juvenile polyposis of stomach with severe anemia. The gross examination of the resection specimen revealed diffuse polyposis throughout the stomach, and histopathological examination revealed hyperplasia of the orbital epithelium throughout the stomach and lack of edema in lamina propria of mucous and eosinophil leukocytic infiltration, leading to the diagnosis of juvenile polyposis of stomach. Two well differentiated adenocarcinomas were found in 2 locations, which remained within the mucosa. We report a case of laparoscopic total gastrectomy for juvenile polyposis of the stomach with gastric cancer, with some discussion of the literature.

Malignant pleural mesothelioma in situ

Although the diagnosis of malignant pleural mesothelioma at an in situ stage was traditionally challenging, it is now possible owing to advances in molecular biological methods such as P16 fluorescence in situ hybridization or BRCA1-associated protein 1 immunohistochemistry. Here, we report the first case, to our knowledge, of total parietal pleurectomy for mesothelioma in situ. Future follow-up and accumulation of cases are necessary to determine whether total parietal pleurectomy could be applied as a treatment for mesothelioma in situ or not.

Paraneoplastic Cerebellar Degeneration With P/Q-VGCC vs Yo Autoantibodies

BACKGROUND AND OBJECTIVES

Paraneoplastic cerebellar degeneration (PCD) is characterized by a widespread loss of Purkinje cells (PCs) and may be associated with autoantibodies against intracellular antigens such as Yo or cell surface neuronal antigens such as the P/Q-type voltage-gated calcium channel (P/Q-VGCC). Although the intracellular location of the target antigen in anti-Yo-PCD supports a T cell-mediated pathology, the immune mechanisms in anti-P/Q-VGCC-PCD remain unclear. In this study, we compare neuropathologic characteristics of PCD with anti-P/Q-VGCC and anti-Yo autoantibodies in an archival autopsy cohort.

METHODS

We performed neuropathology, immunohistochemistry, and multiplex immunofluorescence on formalin-fixed and paraffin-embedded brain tissue of 1 anti-P/Q-VGCC, 2 anti-Yo-PCD autopsy cases and controls.

RESULTS

Anti-Yo-PCD revealed a diffuse and widespread PC loss together with microglial nodules with pSTAT1+ and CD8+granzymeB+ T cells and neuronal upregulation of major histocompatibility complex (MHC) Class I molecules. Some neurons showed a cytoplasmic immunoglobulin G (IgG) staining. In contrast, PC loss in anti-P/Q-VGCC-PCD was focal and predominantly affected the upper vermis, whereas caudal regions and lateral hemispheres were spared. Inflammation was characterized by scattered CD8+ T cells, single CD20+/CD79a+ B/plasma cells, and an IgG staining of the neuropil in the molecular layer of the cerebellar cortex and neuronal cytoplasms. No complement deposition or MHC-I upregulation was detected. Moreover, synaptophysin was reduced, and neuronal P/Q-VGCC was downregulated. In affected areas, axonal spheroids and the accumulation of amyloid precursor protein and glucose-regulated protein 78 in PCs indicate endoplasmatic reticulum stress and impairment of axonal transport. In both PCD types, calbindin expression was reduced or lost in the remaining PCs.

DISCUSSION

Anti-Yo-PCD showed characteristic features of a T cell-mediated pathology, whereas this was not observed in 1 case of anti-P/Q-VGCC-PCD. Our findings support a pathogenic role of anti-P/Q-VGCC autoantibodies in causing neuronal dysfunction, probably due to altered synaptic transmission resulting in calcium dysregulation and subsequent PC death. Because disease progression may lead to irreversible PC loss, anti-P/Q-VGCC-PCD patients could benefit from early oncologic and immunologic therapies.

[A Rare Case of Primary Splenic Malignant Lymphoma Associated with Esophagogastric Junction Neuroendocrine Carcinoma(NEC)]

A 75-year-old man was showed wall thickening just below esophagogastric junction(EGJ)by gastroscopy(GS). Biopsy indicated mucinous carcinoma. He was referred to our hospital. Computed tomography(CT), PET-CT showed EGJ cancer and splenic tumor. EGJ cancer was diagnosed GE, Siewert Type Ⅱ, GrePostAnt, Type 1, cT2, cN0, cM0, cStage Ⅰ. The patient underwent total gastrectomy, lower esophagectomy, D2+ #19, 20, 110, 111, 112 lymph nodes dissection, Rou-en- Y reconstruction, distal pancreatectomy, splenectomy, cholecystectomy, and enterostomy. Postoperative complication was pancreatic fistula(Grade Ⅱ). Pathological diagnosis was esophagogastric junction cancer, neuroendocrine carcinoma(NEC), GE, Siewert Type Ⅱ, GrePostAnt, Type 1, pT2(MP), pN1, pM0, pStage ⅡA. Splenic tumor was diagnosed splenic malignant lymphoma, large B-cell, diffuse(DLBCL), NOS, low-immediate risk. Patient was discharged 15 days after the operation and underwent adjuvant chemotherapy with S-1. In this case, he started taking S-1 because the prognosis of NEC is poorer than PSML. There was no evidence of recurrence after 5 months from gastrectomy. As a result of searching for"neuroendocrine tumor"and"malignant lymphoma"in the JAMAS, there was no report of NEC associated with malignant lymphoma. We experienced the rare case of primary splenic malignant lymphoma associated with EGJ NEC. In the case of gastric cancer with splenic tumor, malignant lymphoma of spleen should be concerned.

[A Case of Gastric Cancer Treated with Resection and Adjuvant Chemotherapy in Japan after FOLFOX Neoadjuvant Chemotherapy in USA]

A 73‒year‒old man, living in the United States since 1985, visited the University of Minnesota Medical Center with a complaint of upper abdominal pain in December 2019. Gastroendoscopy revealed a depressed lesion in the U area of the stomach, and the biopsy results indicated a diagnosis of por/sig. On further examination, the condition was diagnosed as gastric cancer of cStage II/III. A gastrectomy procedure was planned after treatment with neoadjuvant chemotherapy(NAC). After 1 course of mFOLFOX6, the patient decided to undergo treatment in Japan. He travelled to Japan in February and visited our hospital. In March, he underwent total gastrectomy plus D2 dissection plus Roux‒en‒Y reconstruction. The final diagnosis was gastric cancer, U, Less, ypType 2, ypT3(ss), ypN1, sM0, yfStage IIB, and the therapeutic effect was Grade 2. DS therapy was started as adjuvant chemotherapy in April. After 8 courses, he returned to the United States. After moving to the United States, he personally imported S‒1 and continued adjuvant chemotherapy at the University of Minnesota Hospital. The guidelines in Japan do not recommend NAC. Given that Grade 2 therapeutic effect was obtained even with 1 course of the treatment, FOLFOX therapy could be effective as preoperative chemotherapy for advanced gastric cancer cases.

Neuropathology of SCA34 showing widespread oligodendroglial pathology with vacuolar white matter degeneration: a case study

Spinocerebellar ataxia type 34 (SCA34) is an autosomal dominant inherited ataxia due to mutations in ELOVL4, which encodes one of the very long-chain fatty acid elongases. SCA38, another spinocerebellar ataxia, is caused by mutations in ELOVL5, a gene encoding another elongase. However, there have been no previous studies describing the neuropathology of either SCA34 or 38. This report describes the neuropathological findings of an 83-year-old man with SCA34 carrying a pathological ELOVL4 mutation (NM_022726, c.736T>G, p.W246G). Macroscopic findings include atrophies in the pontine base, cerebellum, and cerebral cortices. Microscopically, marked neuronal and pontocerebellar fiber loss was observed in the pontine base. In addition, in the pontine base, accumulation of CD68-positive macrophages laden with periodic acid-Schiff (PAS)-positive material was observed. Many vacuolar lesions were found in the white matter of the cerebral hemispheres and, to a lesser extent, in the brainstem and spinal cord white matter. Immunohistological examination and ultrastructural observations with an electron microscope suggest that these vacuolar lesions are remnants of degenerated oligodendrocytes. Electron microscopy also revealed myelin sheath destruction. Unexpectedly, aggregation of the four-repeat tau was observed in a spatial pattern reminiscent of progressive supranuclear palsy. The tau lesions included glial fibrillary tangles resembling tuft-shaped astrocytes and neurofibrillary tangles and pretangles. This is the first report to illustrate that a heterozygous missense mutation in ELOVL4 leads to neuronal loss accompanied by macrophages laden with PAS-positive material in the pontine base and oligodendroglial degeneration leading to widespread vacuoles in the white matter in SCA34.

A Novel LMX1B Variant Identified in a Patient Presenting with Severe Renal Involvement and Thin Glomerular Basement Membrane

We report a case of nail-patella syndrome (NPS) with unusual thinning of the glomerular basement membrane (GBM) associated with a novel heterozygous variant in the LMX1B gene. A 43-year-old female patient with a previous diagnosis of NPS, referred to our hospital for persistent proteinuria, underwent a renal biopsy, which revealed minor glomerular abnormalities. She underwent a second renal biopsy at the age of 56 owing to the presence of persistent proteinuria and decline in serum albumin, meeting the diagnostic criteria for nephrotic syndrome. Light microscopy demonstrated glomerulosclerosis and cystic dilatation of the renal tubules. Notably, electron microscopy revealed unusual thinning of the GBM, which is quite different from typical biopsy findings observed in patients with NPS, characterized by thick GBM with fibrillary material and electron-lucent structures. Comprehensive genetic screening for 168 known genes responsible for inherited kidney diseases using a next-generation sequencing panel identified a novel heterozygous in-frame deletion-insertion (c.723_729delinsCAAC: p.[Ser242_Lys243delinsAsn]) in exon 4 of the LMX1B gene, which may account for the disrupted GBM structure. Further studies are warranted to elucidate the complex genotype-phenotype relationship between LMX1B and proper GBM morphogenesis.

Membranous nephropathy in a patient with pulmonary tuberculosis infection and lung adenocarcinoma: a case report

We report a case of membranous nephropathy (MN) in a patient with tuberculosis infection and lung adenocarcinoma. A 50-year-old Filipino woman underwent a renal biopsy for the evaluation of proteinuria and hematuria. Immunofluorescence analysis revealed positive staining of IgG in the glomerular basement membrane and mesangial matrices, while electron microscopy demonstrated the presence of sub-epithelial deposits, suggesting MN. To screen for secondary causes of MN, we conducted a computed tomography (CT) scan of the chest and abdomen, which revealed a ground-glass opacity in the middle lobe of the right lung and an enlarged paraaortic lymph node. A T-SPOT test was positive, suggesting the possibility of a latent tuberculosis infection, as she was asymptomatic. A follow-up chest CT scan showed persistent presence of the ground-glass opacities, suggesting a non-infectious cause. Video-assisted thoracoscopic resection of the middle right lobe and partial resection of the lower right lobe were performed because the possibility of lung cancer could not be excluded. Notably, pathological analysis of the lung revealed adenocarcinoma in the middle lobe and epithelioid granuloma in the lower lobe, suggesting an active tuberculosis infection. One month after surgery, anti-tuberculosis treatment was initiated. Thereafter, her proteinuria, which had increased to 6 g/gCre preoperatively, began to decrease. Five months after surgery, the patient achieved complete remission. The speed of remission suggests that tuberculosis likely played a primary role in the etiology of MN. Our case underscores the importance of screening tests for infections and malignancies in patients with MN, even if suggestive symptoms are absent.

Immunotactoid glomerulonephritis in a patient with cold agglutinins: causal association or mere coincidence?

We report a case of immunotactoid glomerulonephritis (ITG) in a patient with cold agglutinins. An 86-year-old Japanese male with a history of hypertension, dyslipidemia, and gastric malignancy presented to our hospital for the evaluation of proteinuria and hematuria. He had an elevated blood pressure of 200/77 mmHg and edema of the lower extremities. Initial blood test results revealed an impaired renal function (creatinine, 1.37 mg/dL) and hypoalbuminemia (albumin, 2.6 g/dL). His estimated daily urinary protein was 5.89 g/g creatinine, meeting the diagnostic criteria for nephrotic syndrome. The selectivity index for proteinuria indicated low selectivity (0.329). We conducted a renal biopsy to identify the cause of nephrotic syndrome. Immunofluorescence microscopy demonstrated positive staining of IgM, C4, and C1q. Electron microscopy exhibited mesangial expansion with inflammatory cells and a lobular structure, suggesting membranoproliferative glomerulonephritis. Subendothelial deposits containing microtubular structures with a diameter of approximately 30-200 nm were found, concurrent with the criteria for the diagnosis of ITG. Screening for lymphoproliferative diseases and immunological abnormalities revealed a positive direct Coombs test result and the presence of cold agglutinins. Paraproteinemia was absent. The similarities between cold agglutinin disease and ITG, including the production of autoantibodies and involvement of complement pathways, raise the possibility that cold agglutinins played a role in the development of ITG; however, we were unable to prove it due to difficulties in detecting cold agglutinins on renal histology. We discuss the possible implications for pathogenesis considering prior reports on nephrotic syndrome being potentially associated with cold agglutinins.

Ruptured infected aneurysm of the thoracic aorta associated with tunneled dialysis catheter-related methicillin-resistant Staphylococcus aureus bacteremia in a hemodialysis patient

Patients with an indwelling tunneled dialysis catheter (TDC) for hemodialysis access are at a high risk of developing methicillin-resistant Staphylococcus aureus (MRSA) infection. MRSA bacteremia complications rarely include infected aneurysm. Here, we report the first case of an infected thoracic aneurysm associated with TDC-related MRSA bacteremia. An 86-year-old Japanese male with a TDC for hemodialysis access developed TDC-related MRSA bacteremia. Intravenous vancomycin was initiated, and the TDC was removed on day 3. Despite removal of the catheter and initiation of vancomycin treatment, MRSA bacteremia persisted. Chest computed tomography (CT) showed no aneurysm; however, calcification of the thoracic aorta was detected on admission. The patient subsequently developed hemosputum. CT revealed a thoracic aneurysm, which turned out to be caused by MRSA bacteremia. The patient eventually died because of the rupture of the infected aneurysm, as confirmed by autopsy. This report demonstrates TDC management in a patient with TDC-related MRSA bacteremia and the importance of investigating a metastatic infection to a calcified artery if bacteremia persists.

Primary amelanotic malignant melanoma of the male urethra with inguinal lymph node metastasis successfully controlled by nivolumab: A case report

We report a rare case of primary amelanotic malignant melanoma of the male urethra. A 65-year-old man with a urethral mass was referred to our hospital. A pathological diagnosis of a biopsy specimen revealed malignant melanoma. Thereafter, the patient underwent partial penectomy. The histopathological diagnosis was amelanotic malignant melanoma of the urethra. The patient had received DAV-Feron in an adjuvant setting; however, PET-CT revealed multiple metastasis. After receiving more than 10 cycles of nivolumab, the accumulation of FDG was no longer observed on PET-CT. The patient is currently free from recurrence at 20 months after nivolumab treatment.

Female Urethral Diverticulum Carcinoma: A Case Report and Literature Review

A 48-year-old woman with a history of voiding difficulty visited our hospital. Magnetic resonance imaging revealed a periurethral tumor, which was pathologically diagnosed as an adenocarcinoma via transperineal needle biopsy. Radical cystectomy and urethrectomy were performed, and the urinary tract was reconstructed using an ileal conduit. Pathological examination of a resected specimen confirmed adenocarcinoma of the urethral diverticulum. The patient received adjuvant gemcitabine and cisplatin chemotherapy. She is alive at 5 months since the operation.

HEG1 is a novel mucin-like membrane protein that serves as a diagnostic and therapeutic target for malignant mesothelioma

The absence of highly specific markers for malignant mesothelioma (MM) has served an obstacle for its diagnosis and development of molecular-targeting therapy against MM. Here, we show that a novel mucin-like membrane protein, sialylated protein HEG homolog 1 (HEG1), is a highly specific marker for MM. A monoclonal antibody against sialylated HEG1, SKM9-2, can detect even sarcomatoid and desmoplastic MM. The specificity and sensitivity of SKM9-2 to MM reached 99% and 92%, respectively; this antibody did not react with normal tissues. This accurate discrimination by SKM9-2 was due to the recognition of a sialylated O-linked glycan with HEG1 peptide. We also found that gene silencing of HEG1 significantly suppressed the survival and proliferation of mesothelioma cells; this result suggests that HEG1 may be a worthwhile target for function-inhibition drugs. Taken together, our results indicate that sialylated HEG1 may be useful as a diagnostic and therapeutic target for MM.

[A Case of Synchronous Malignant Pheochromocytomas in Bilateral Adrenal Glands]

We present a case of synchronous malignant pheochromocytoma in bilateral adrenal glands. A 73- year-old man presented to our hospital with bilateral adrenal masses incidentally found during abdominal ultrasonography examination for an unrelated issue. The patient had a 30-year history of hypertension and paroxysmal atrial fibrillation. Computed tomography and magnetic resonance imaging showed heterogeneous tumors in bilateral adrenal glands and an enlarged para-aortic lymph node. Hormonal examinations revealed a high value of urinary catecholamines. Metaiodobenzylguanidine (MIBG) scintigraphy showed increased uptake in bilateral adrenal glands and the lymph node. Both adrenal tumors and the node were surgically removed. Pathological examination revealed histologically distinct tissue between the two adrenal tumors. The patient received five cycles of adjuvant chemotherapy, consisting of cyclophosphamide, vincristine, and dacarbazine. The patient has been in remission for 32 months following surgical treatment.

Chronic Hepatitis E Infection in a Persistently Immunosuppressed Patient Unable to Be Eliminated after Ribavirin Therapy

Recent case reports have shown that hepatitis E virus (HEV) infection can cause chronic hepatitis in immunosuppressed or immunocompromised patients. A 37-year-old woman suffered from prolonged elevation of aminotransferases after chemotherapy for Burkitt's lymphoma and was diagnosed with chronic hepatitis E due to a transfusion during chemotherapy. After an 8-month administration of ribavirin, complete HEV clearance was not achieved, likely due to prolonged hypogammaglobulinemia. This case indicates that HEV infection should be ruled out during liver dysfunction in immunosuppressed or immunocompromised patients and suggests that an alternative therapeutic strategy for such patients will be needed.

[Undifferentiated carcinoma of the jejunum producing granulocyte colony-stimulating factor]

An 80-year-old man presented with abdominal fullness and vomiting. Laboratory data revealed severe anemia, an inflammatory response, and elevated white blood cell counts. Abdominal computed tomography indicated ileus caused by a jejunal tumor measuring 8cm in diameter. Although small-bowel endoscopy enabled visualization of the tumor, adequate biopsy specimens could not be obtained for accurate diagnosis. The patient's condition rapidly deteriorated, because of which surgical treatment could not be initiated. The patient died approximately 3 weeks after admission. High serum granulocyte colony-stimulating factor (G-CSF) levels were detected at autopsy. Immunohistochemical staining of the autopsy specimen indicated positive G-CSF levels in the jejunal tumor. On the basis of these findings, a final diagnosis of undifferentiated carcinoma of the jejunum producing G-CSF was made.

Sarcoidosis in a chronic dialysis patient diagnosed by sarcoidosis-related hypercalcemia with no common systemic clinical manifestations: a case report and review of the literature

Sarcoidosis is a systemic granulomatous disease of unknown origin. We herein report a case of sarcoidosis in a chronic dialysis patient diagnosed by hypercalcemia without any common clinical manifestations. The onset of sarcoidosis in chronic dialysis patients is rare; to the best of our knowledge, only 23 cases have been reported. Evaluation of the 23 previously published cases revealed that a diagnosis of sarcoidosis was often achieved by the presence of sarcoidosis-related hypercalcemia without any common clinical presentations, as in the present case. This characteristic may arise from a specific immune deficiency and the unique physiology of 1,25-dihydroxyvitamin D3, a main cause of sarcoidosis-related hypercalcemia, in chronic dialysis patients. These clinical features may be useful to understand the pathogenesis of sarcoidosis.

Recovery of renal function in a dialysis-dependent patient with microscopic polyangiitis and both myeloperoxidase anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane antibodies

A 40-year-old man with microscopic polyangiitis developed both myeloperoxidase anti-neutrophil cytoplasmic antibodies (90 EU) and anti-glomerular basement membrane antibodies (134 EU)-positive rapidly progressive glomerulonephritis and heparin-induced thrombocytopenia. Although the patient initially showed no signs of improvement, persistent therapy including 1 g/day intravenous methylprednisolone, 50 mg/day oral prednisolone, plasma exchange, and 900 mg/day intravenous cyclophosphamide resulted in the normalization of both titers, recovery of renal function, and discontinuation of dialysis. Though previous studies showed poor outcomes in such "double-positive" patients, aggressive immunosuppression in younger patients may result in the recovery of renal function, even in those with severe renal dysfunction.

[Pancreatic metastasis from renal cell carcinoma 25 years after radical nephrectomy]

We report a case of pancreatic metastasis from renal cell carcinoma detected 25 years after radical nephrectomy. A 74-year-old man, who had undergone radical nephrectomy for renal cell carcinoma at age 49, was found by computed tomography to have a strongly enhanced mass on the pancreatic head. The patient underwent pancreaticoduodenectomy and the pathological diagnosis was metastatic renal cell carcinoma. This was evidently a slow growing tumor because the metastatic pancreas tumor was well demarcated and the metastasis was found 25 years after the primary operation. Aggressive surgical treatment of isolated metastatic lesions offers a chance of long-term survival. Patients with a history of RCC should undergo a long-term follow-up to detect and evaluate metastasis to pancreas as well as other organs.

Secretion of intelectin-1 from malignant pleural mesothelioma into pleural effusion

Background:

Malignant pleural mesothelioma (MPM) is a rare but fatal tumour. Although most MPM patients show pleural effusion at even the early stage, it is hard to diagnose as MPM at the early stage because a sensitive and reliable diagnostic marker for MPM has not been found in plasma or pleural effusion.

Methods:

In this study, we investigated whether intelectin-1 was specifically contained in MPM cells and the pleural effusion of MPM patient by immunohistochemistry, western blotting, and enzyme-linked immunosorbent assay.

Results:

Malignant pleural mesothelioma cell lines, but not lung adenocarcinoma cell lines, secreted intelectin-1. In immunohistochemistry, epithelioid-type MPMs, but neither pleura-invading lung adenocarcinomas nor reactive mesothelial cells near the lung adenocarcinomas, were stained with anti-intelectin antibodies. Pleural effusion of MPM patients contained a higher concentration of intelectin-1 than that of lung cancer patients.

Conclusion:

These results suggest that detection of intelectin-1 may be useful for a differential diagnosis of epithelioid-type MPM in immunohistochemistry and that a high concentration of intelectin-1 in pleural effusion can be used as a new marker for clinical diagnosis of MPM.

[A case of giant retroperitoneal paraganglioma]

Paraganglioma is a rare neuroendocrine tumor which arises from extra adrenal paraganglionic cells of the autonomic nervous system. We report a case of a giant retroperitoneal paraganglioma. A 43-year-old man referred to our hospital for further examination of a retroperitoneal mass. The patient had neither familial nor past medical history. The blood and urine test, laboratory examinations including cathecolamines, were unremarkable. Abdominal computed tomography showed an enhancing solid mass 13 cm in diameter on the left kidney. The invasion to the left kidney was suspected. Angiography showed the left renal, splenic, middle suprarenal and left inferior diaphragmatic artery feeding the tumor. The splenic and left inferior diaphragmatic artery were embolized before surgical treatment. The tumor, left kidney, adrenal gland and spleen were surgically resected. Histological examination revealed extra-adrenal paraganglioma, and there was no invasion of the tumor to the left kidney, adrenal gland and spleen. The patient has now survived more than 10 months following the surgery without tumor recurrence.

[Verrucous carcinoma of penis: a case report]

We report a case of verrucous carcinoma of the penis. A 62-year-old man, who presented with penile swelling and pain, was referred to our hospital. Although, penile tumor biopsy revealed no evidence of malignancy, the patient presented with penile swelling and discharge. The penis was surgically resected and urinary diversion was performed. The pathological examination of the resected glans revealed verrucous carcinoma of penis. Furthermore, in situ hybridization revealed human papilloma virus (HPV) infection. This clearly showed that the verrucous carcinoma of the penis resulted from the HPV infection. The patient has survived for 14 months after surgery without local recurrence or metastasis.

Sight-threatening optic neuropathy is associated with paranasal lymphoma

Malignant lymphoma around the orbit is very rare. We present a rare case of optic neuropathy caused by lymphoma. A 61-year-old Japanese woman was referred to our hospital for evaluation of idiopathic optic neuropathy affecting her right eye. The patient was treated with steroid pulse therapy (methyl-predonisolone 1 g daily for 3 days) with a presumed diagnosis of idiopathic optic neuritis. After she had been switched to oral steroid therapy, endoscopic sinus surgery had been performed, which revealed diffuse large B cell lymphoma of the ethmoidal sinus. Although R-CHOP therapy was immediately started, prolonged optic nerve compression resulted in irreversible blindness. Accordingly, patients with suspected idiopathic optic neuritis should be carefully assessed when they show a poor response, and imaging of the orbits and brain should always be done for initial diagnosis because they may have compression by a tumor.

[Metanephric adenoma: report of two cases]

We report 2 cases of metanephric adenoma a rare form of adenoma. One case occurred in a 54-year-old male preoperatively diagnosed with renal cell carcinoma who underwent left partial nephrectomy for a tumor 2 cm in size. Histology revealed a tumor with papillotubular structures consisting of small, uniform tumor cells. In immunohistochemical staining, tumor cells were positive for CD57 and WT-1. Thus, the patient was diagnosed with metanephric adenoma. The other case occurred in a 40-year-old male who underwent left nephroureterectomy for carcinoma of the renal pelvis. Carcinoma of the left renal pelvis was diagnosed as pT3N0M0. Incidental micronodules 2 mm in size and consisting of immature tubular structures were noted in the renal cortex. In immunohistochemical staining, tumor cells were positive for CD57 and WT-1, and the patient was diagnosed with metanephric adenoma. The aforementioned tumors frequently occur in middle-aged women and are often well-defined tumors that project from the renal surface outwards. On angiography, they have a hypovascular pattern and resemble papillary renal carcinoma. Preoperative differentiation of renal cell carcinoma and nephroblastoma is difficult. Mistaking such tumors for malignant tumors and subjecting patients to unnecessary adjuvant therapy must be avoided.

A case of lymphoepithelioma-like carcinoma of the colon with ulcerative colitis

Follow-up colonoscopy of a 25-year-old Japanese man with ulcerative colitis (UC) who had undergone endoscopic mucosal resection twice for early colon cancers revealed the presence of a new 1.5-cm-diameter tumor in the sigmoid colon. It was diagnosed by preoperative biopsy as a poorly differentiated adenocarcinoma. Sigmoidectomy was performed, and the pathological findings revealed lymphoepithelioma-like carcinoma (LEC). In situ hybridization to detect Epstein-Barr virus (EBV)-encoded small RNAs showed positive signals in stromal lymphocytes, but weak signals in the tumor cells. The association between EBV and LEC was obscure in this case. Unlike typical UC-mediated colon cancers, the lesion was poorly differentiated, and negative for p53 signals immunohistochemically. These findings may hint at a novel mechanism of carcinogenesis in UC-mediated colorectal cancer.

Renal oncocytosis

Renal oncocytosis is a rare disorder in which numerous oncocytic nodules develop in the kidney. An additional case is reported here. The patient was a 51-year-old woman who had received hemodialysis for 27 years. Nineteen years previously she had developed a tumorous lesion in the right kidney, which had been diagnosed as oncocytoma with laparotomic biopsy. Recently the kidney was removed because of enlargement of the tumor. The renal parenchyma was entirely replaced with numerous brownish nodules. Histologically, the nodules were composed of nests of uniform oncocytic cells. Ultrastructurally, the oncocytic cells contained numerous mitochondria. Immunohistochemical features of the nodules were identical to those of sporadic oncocytomas, that is, immunophenotypes similar to the distal nephron and reactivity with antimitochondrial antigen. Based on these findings, the lesion was diagnosed as renal oncocytosis. It was not possible to determine whether the larger nodules should be diagnosed as oncocytoma or a part of oncocytosis. Additionally, the germ line mutation of the Birt-Hogg-Dubé (BHD) syndrome gene was examined using the genomic DNA obtained from the peripheral lymphocytes, which failed to show any gene alteration. Despite the rare occurrence pathologists and urologists should be aware of renal oncocytosis, as a precursor lesion of renal oncocytoma and chromophobe renal cell carcinoma.

Objective definition and measurement method of ground-glass opacity for planning limited resection in patients with clinical stage IA adenocarcinoma of the lung1

OBJECTIVE

The standard operation for patients with stage IA lung adenocarcinoma is considered to be a lobectomy. Recently, some researchers have reported that patients with tumors showing greater proportions of ground-glass opacity (GGO) at computed tomography (CT) could be candidates for limited resection, because of its less aggressive nature. However, the lack of a precise definition or standard measuring method of GGO prevents its general use as an index for planning limited resection. Therefore, we attempted to define GGO based on CT number and measured it more objectively.

METHODS

Between 1998 and 2001, 90 patients with clinical stage IA adenocarcinoma, who underwent standard or intentional limited resection and whose images of chest high-resolution CT were preserved in Digital Imaging and Communications in Medicine (DICOM) format, constituted the study population. The tumor shadow seen on the solid window (WL, -160HU; WW, 2HU) was regarded as the central solid area of the tumor seen on the lung window, and GGO was defined as the whole tumor area with the exception of the central solid area. Each area was measured using Scion Image (Scion Corp., Frederick, MD). We analyzed the relationship between the proportion of GGO and both of pathologic findings and recurrence.

RESULTS

Among the 90 tumors, 31 (34.4%) were calculated to have a GGO area greater than or equal to 50%. Of these, 27 (87%) tumors were bronchioloalveolar carcinoma. Lymphatic and vascular invasions, or nodal involvement were found only in patients with a smaller proportion of GGO (<50%) (P < 0.05). During the follow-up period (median 36 months), recurrences occurred in eight patients who were diagnosed as having tumors showing smaller proportion of GGO (<50%).

CONCLUSIONS

Tumors with a greater proportion of GGO measured by our method are thought to have a less invasive nature. Our objective measuring method of GGO could be useful for future multicenter trials to elucidate the value of limited resection for clinical stage IA adenocarcinoma based on the proportion of GGO.

Proportion of ground-glass opacity on high-resolution computed tomography in clinical T1 N0 M0 adenocarcinoma of the lung: A predictor of lymph node metastasis

OBJECTIVE

In patients with clinical T1 N0 M0 lung adenocarcinoma, we investigated whether the proportion of ground-glass opacity area measured on high-resolution computed tomography was valuable for predicting the existence of lymph node metastasis, lymphatic invasion, or vascular invasion.

METHODS

Between 1994 and 1999, 111 patients with clinical stage IA adenocarcinoma underwent surgical resection of the lung at our hospital. Of these, 96 patients received high-resolution computed tomography of the chest, and they constituted the study population. The tumors were semiquantitatively classified into 5 groups on the basis of the proportion of ground-glass opacity area to whole tumor shadow on high-resolution computed tomography: group I, 0%; group II, 1% to 25%; group III, 26% to 50%; group IV, 51% to 75%; and group V, 76% to 100%. Correlations of computed tomographic findings, pathologic results of lymph node metastasis and lymphatic and vascular invasion, and the histologic subtype according to the new World Health Organization classification were examined. We also investigated the characteristics of the patients with ground-glass opacity areas on high-resolution computed tomography and their value for predicting lymph node metastasis.

RESULTS

Among the 96 patients, 15 (15.6%) had mediastinal lymph node metastases, and 3 (3.1%) had hilar node metastases. Regarding the proportion of the ground-glass opacity area of the tumors, 15 (15.6%) tumors were classified as group V, 11 (11.5%) as group IV, 9 (9.3%) as group III, 22 (22.9%) as group II, and 39 (40.6%) as group I, respectively. Of the 18 patients with lymph node metastases, no patients were found in groups IV and V, 2 (22.2%) were found in group III, 4 (18.2%) were found in group II, and 12 (30.8%) were found in group I (trend P =. 003), respectively. Twenty-six patients classified into groups IV and V also showed neither lymphatic invasion nor recurrence. All the smaller tumors (< or =2.0 cm) in group IV or V were histologically proved to be bronchioloalveolar carcinoma. Adjusted for smoking status and other characteristics, patients without ground-glass opacity on high-resolution computed tomography had a significantly increased risk of concurrent lymph node metastasis compared with those with ground-glass opacity.

CONCLUSION

In patients with clinical T1 N0 M0 adenocarcinoma, the proportion of ground-glass opacity area on thin-section computed tomography scans was a strong predictor for tumor aggressiveness and thus could be a useful index for planning limited surgical resection for these patients.

Expression of c-kit protein in proliferative lesions of human breast: sexual difference and close association with phosphotyrosine status

PURPOSE

The c-kit gene which codes transmembrane tyrosine kinase receptor protein plays an important role in several types of normal and/or neoplastic human tissues. We examined the expression patterns of c-kit protein in proliferative lesions of human breast tissues in both sexes.

METHODS

The localization of c-kit protein was examined immunohistochemically in human breast, consisting of 366 normal tissue, 156 benign lesions (fibroadenoma, fibrocystic change, intraductal papilloma, benign phyllodes tumor, and gynecomastia), 13 borderline diseases (atypical ductal hyperplasia, atypical lobular hyperplasia, and borderline malignant phyllodes tumor), and 197 malignant lesions (non-invasive and/or invasive ductal carcinoma and malignant phyllodes tumor).

RESULTS

In normal tissues and benign proliferative lesions, c-kit product was consistently detected on epithelial cell membranes and/or cytoplasms regardless of gender difference. In contrast, we failed to find c-kit product in female borderline epithelial lesions, including atypical lobular hyperplasia, or in female malignant lesions, except for two carcinomas. In situ hybridization analysis of c-kit mRNA in female tissues gave results comparable to those obtained by immunohistochemistry. On the other hand, c-kit product was consistently detected in male benign and malignant proliferative lesions. Apart from the female breast carcinomas which lacked c-kit, c-kit expression was almost always accompanied by positivity for phosphotyrosine in the breast tissues examined, suggesting possible phosphorylation of tyrosine residues of the c-kit receptor protein.

CONCLUSIONS

Loss of c-kit product was related to malignant transformation in female breast, but not in the case of male breast. We suggest that the oncogenesis pathway of breast epithelium is different between males and females in terms of c-kit expression.

Recovery of function and mass of endogenous beta-cells in streptozotocin-induced diabetic rats treated with islet transplantation

Islet transplantation corrects chronic hyperglycemia by augmentation of insulin supply from the graft tissue, but the role of endogenous beta-cells after transplantation is not clear. In the present study, we examined endogenous beta-cell function after glucose homeostasis had been reestablished by islet graft in streptozotocin (STZ)-induced diabetic rats. Fed plasma glucose levels in diabetic rats transplanted with a large number of islets (2500 islets) into the left kidney capsule soon became lower (139.8 +/- 8.2 mg/dl) and close to the level in controls (129.7 +/- 11.3 mg/dl), and IPGTT exhibited a pattern of plasma glucose response almost identical to control. The insulin and DNA contents, islet area, and the distribution of beta-cells that were markedly deteriorated in islets of STZ rats were significantly restored in transplanted rats. The insulin release in response to glucose or alpha-ketoisocaproate was less in STZ rats, while in islets of transplanted rats the secretion recovered to levels similar to controls. On the other hand, arginine-induced insulin release was conversely hyperresponsive in STZ rats, but in transplanted rats, the response was decreased similar to controls. Thus, as the plasma glucose level normalizes, residual beta-cells show a recovery of function that cannot be accounted for by the increase in mass alone.

Heat shock restores insulin secretion after injury by nitric oxide by maintaining glucokinase activity in rat islets

Heat shock protein (hsp), including hsp70, has been reported to restore the glucose-induced insulin release suppressed by nitric oxide (NO). However, the mechanism underlying this recovery remains unclear. In the present study, we examine the effects, in rat islets, of heat shock on insulin secretion inhibited by a small amount of NO and also on glucose metabolism, the crucial factor in insulin release. Exposure to a higher dose (15 U/ml) of interleukin-1beta (IL-1beta) abolished the insulin release by stimulation of glucose or KCl in both control and heat shocked islets. In rat islets exposed to a lower dose (1.5 U/ml) of IL-1beta, insulin secretion in response to glucose, but not to glyceraldehydes (GA), ketoisocaproate (KIC), or KCl, was selectively impaired, concomitantly with lower ATP concentrations in the presence of 16.7 mM glucose, while such suppression of insulin secretion and ATP content was not observed in heat shock-treated islets. NO production in islets exposed to 1.5 U/ml IL-1beta was significantly, but only partly, decreased by heat shock treatment. The glucose utilization rate measurement using [5-3H]-glucose and [2-3H]-glucose and the glucokinase activity in vitro were reduced in islets treated with 1.5 U/ml IL-1beta. In heat shock-treated islets, glucose utilization and glucokinase activity were not affected by 1.5 U/ml IL-1beta. These data suggest that heat shock restores glucose-induced insulin release inhibited by NO by maintaining glucokinase activity and the glucose utilization rate in islets in addition to reducing endogenous NO production.

Distinct effect of diazoxide on insulin secretion stimulated by protein kinase A and protein kinase C in rat pancreatic islets

Protein kinase activation is known to stimulate glucose-induced insulin secretion in the presence of diazoxide. Diazoxide opens the ATP-sensitive K(+) channel and inhibits FAD-linked glycerophosphate dehydrogenase activity in a concentration-dependent manner. In the present study, we examined the effect of lower (100 microM) and higher (250 microM) concentrations of diazoxide on insulin release by protein kinase A (PKA) and protein kinase C (PKC) activation. Forced depolarization by a high potassium concentration, augmented the intracellular Ca(2+) concentration ([Ca(2+)](i)) similarly in the presence of both concentrations of diazoxide. Under this condition, 250 microM diazoxide inhibited insulin release enhanced by PKA activation but not that by PKC. Under a basal concentration of [Ca(2+)](i), PKC activation elicited glucose-induced insulin secretion at 100 and 250 microM diazoxide, while PKA activation did so only at 100 microM. These augmentations were completely inhibited by mannoheptulose, a glucokinase inhibitor. Glyceraldehyde, in place of glucose, enhanced insulin secretion by PKC activation under both concentrations of diazoxide. On the other hand, it did not affect PKA-stimulated insulin release under either conditions, but in the case of 100 microM, glucose augmented the insulin secretion in the presence of glyceraldehyde and db-cAMP concentration-dependently. These data suggest that insulin release stimulated by PKA and PKC activation under diazoxide is dependent on glucose metabolism, and that a signal derived from proximal steps in glycolysis may be necessary for the secretion by PKA activation.

Genomic variation in pancreatic ion channel genes in Japanese type 2 diabetic patients

BACKGROUND

Many genetic diseases are caused by mutations in ion channel genes. Because type 2 diabetes is characterized by pancreatic beta-cell insensitivity to glucose, the genes responsible for glucose metabolism and calcium signaling in pancreatic beta-cells are candidate type 2 diabetes susceptibility genes.

METHODS

We have examined genomic variations in two ion channel genes relevant to the molecular pathology of diabetes mellitus, the Kir6.2 subunit of the ATP-sensitive potassium channel gene and alpha(1D) subunit of the voltage-dependent calcium channel (VDCC) gene among Japanese type 2 diabetic patients.

RESULTS

There are two alleles in the Kir6.2 gene: EI, glutamic acid at codon 23 and isoleucine at codon 337 and KV, lysine at codon 23 and valine at codon 337. The allelic frequencies of these polymorphisms are similar in type 2 diabetic patients and normal subjects. We also detected trinucleotide repeat polymorphisms in the amino terminus and the carboxyl terminal region of the alpha(1D) gene. Expansion of the ATG trinucleotide repeat from seven to eight was detected only in type 2 diabetic patients, but the frequency was low and was similar in type 2 diabetic patients and normal subjects.

CONCLUSIONS

Although variations of the Kir6.2 and alpha(1D) genes are not associated with the development of common type 2 diabetes, further studies may determine the role of these genomic variations, especially those in the alpha(1D) VDCC gene, in the pathogenesis of certain subsets of type 2 diabetes, or as a co-factor in the polygenic disorder generally.

A novel glucokinase regulator in pancreatic beta cells: precursor of propionyl-CoA carboxylase beta subunit interacts with glucokinase and augments its activity

A glucokinase regulatory protein has been reported to exist in the liver, which suppresses enzyme activity in a complex with fructose 6-phosphate, whereas no corresponding protein has been found in pancreatic beta cells. To search for such a protein in pancreatic beta cells, we screened for a cDNA library of the HIT-T15 cell line with the cDNA of glucokinase from rat islet by the yeast two hybrid system. We detected a cDNA encoding the precursor of propionyl-CoA carboxylase beta subunit (pbetaPCCase), and glutathione S-transferase pull-down assay illustrated that pbetaPCCase interacted with recombinant rat islet glucokinase and with glucokinase in rat liver and islet extracts. Functional analysis indicated that pbetaPCCase decreased the K(m) value of recombinant islet glucokinase for glucose by 18% and increased V(max) value by 23%. We concluded that pbetaPCCase might be a novel activator of glucokinase in pancreatic beta cells.

Augmentation of basal insulin release from rat islets by preexposure to a high concentration of glucose

We have found that preexposure to an elevated concentration of glucose reversibly induces an enhancement of basal insulin release from rat pancreatic islets dependent on glucose metabolism. This basal insulin release augmented by priming was not suppressed by reduction of the intracellular ATP or Ca(2+) concentration, because even in the absence of ATP at low Ca(2+), the augmentation was not abolished from primed electrically permeabilized islets. Moreover, it was not inhibited by an alpha-adrenergic antagonist, clonidine. A threshold level of GTP is required to induce these effects, because together with adenine, mycophenolic acid, a cytosolic GTP synthesis inhibitor, completely abolished the enhancement of basal insulin release due to the glucose-induced priming without affecting the glucose-induced increment in ATP content and ATP-to-ADP ratio. In addition, a GDP analog significantly suppressed the enhanced insulin release due to priming from permeabilized islets in the absence of ATP at low Ca(2+), suggesting that the GTP-sensitive site may play a role in the augmentation of basal insulin release due to the glucose-induced priming effect.

An insulinotropic effect of vitamin D analog with increasing intracellular Ca2+ concentration in pancreatic beta-cells through nongenomic signal transduction

The effect of 1alpha,25-dihydroxylumisterol3 (1alpha,25(OH)2lumisterol3) on insulin release from rat pancreatic beta-cells was measured to investigate the nongenomic action of vitamin D via the putative membrane vitamin D receptor (mVDR). 1Alpha,25(OH)2lumisterol3, a specific agonist of mVDR, dose-dependently augmented 16.7 mM glucose-induced insulin release from rat pancreatic islets and increased the intracellular Ca2+ concentration ([Ca2+]i), though not increasing Ca2+ efficacy in the exocytotic system. These effects were completely abolished by an antagonist of mVDR, 1beta,25-dihydroxyvitamin D3 (1beta,25(OH)2D3), or by a blocker of voltage-dependent Ca2+ channels, nitrendipine. Moreover, both [Ca2+]i elevation, caused by membrane depolarization, and sufficient intracellular glucose metabolism are required for the expression of these effects. 1Alpha,25(OH)2lumisterol3, therefore, has a rapid insulinotropic effect, through nongenomic signal transduction via mVDR, that would be dependent on the augmentation of Ca2+ influx through voltage-dependent Ca2+ channels on the plasma membrane, being also linked to metabolic signals derived from glucose in pancreatic beta-cells. However, further investigations will be needed to discuss physiologically the meaning of insulinotropic effects of vitamin D through mVDR.

Regulation of intracellular ATP concentration under conditions of reduced ATP consumption in pancreatic islets

ATP is the most important factor in glucose-induced insulin secretion in pancreatic beta-cells, but examination of intracellular differences in ATP concentration is difficult because ATP production and consumption occur simultaneously. In the present study, we measured the ATP concentration under the condition of a reduced ATP requirement by omitting extracellular Ca(2+) and inhibiting Na-K ATPase. The ATP concentration in islets incubated with 16.7 mM glucose in the absence of Ca(2+) for 30 min was increased by about 1. 9-fold more than in the presence of Ca(2+). The increment was extracellular Ca(2+)-dependent, and was completely abolished by the metabolic inhibitors dinitrophenol and iodoacetic acid. The Ca channel blockers including nitrendipine and Ni(2+) did not affect the ATP concentration in islets incubated with 16.7 mM glucose in the presence of Ca(2+). However, when thapsigargin and suramin, inhibitors of Ca-ATPase at the endoplasmic reticulum, were added to Ca channel blockers in the presence of ambient Ca(2+), the intraislet ATP content was increased, similarly to that under Ca-free conditions. But thapsigargin did not further augment the ATP concentration in the islet with 16.7 mM glucose in the absence of Ca(2+). On the other hand, the suppression of Na-K ATPase by ouabain rather reduced the ATP concentration augmented by omission of extracellular Ca(2+). In addition, vanadate, a blocker of Ca-ATPase at the plasma membrane, failed to increase the ATP concentration in the islets. These data suggest that the increment of ATP concentration in the absence of Ca(2+) is attributable to the reduced ATP requirement due to stopping of the Ca-ATPase activity at the endoplasmic reticulum, and that the intracellular ATP concentration is differently regulated by Na-K ATPase at plasma membrane and by Ca-ATPase at endoplasmic reticulum.