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Biomedical subjects

M Hirokawa

Publications and source records attributed to M Hirokawa.

At least 73 records · Page 4Linked to original sources
PubMed2000

[A case of retroperitoneal teratoma difficult to distinguish from adrenal myelolipoma].

A 59-year-old man presented to our hospital suspected of having cholelithiasis. Computed tomography (CT) scan revealed a left retroperitoneal solid tumor cephalad to the kidney, 7 x 8 x 9 cm in size with mostly a fatty density area and focal calcification. Magnetic resonance imaging (MRI) on T1 and T2 weighted images showed a high intensity mass. Angiography revealed the hypovascular tumor. Although we had suspected it to be an adrenal myelolipoma, tumorectomy was performed because of its size. Pathological diagnosis was mature teratoma. Although retroperitoneal teratoma contains fas, cyst, soft tissue and calcification, the proportion of fat in the tumor is usually less than that of adrenal myelolipoma. In our case, the tumor contained more fat than the 'typical' retroperitoneal teratoma, which led to the misdiagnosis.

Adrenal Gland Neoplasms↗
PubMed2000

[Fournier's gangrene in a patient with malignant lymphoma: a case report].

We report a case of Fournier's gangrene. An 83-year-old man underwent biopsy of left inguinal tumor as an outpatient. Pathological diagnosis was malignant lymphoma (diffuse large cell type). Three weeks later, he developed reddened scrotal swelling accompanied with high fever (> 39 degrees C). On admission, antibiotic chemotherapy was initiated. Although his general condition was improved, scrotal necrosis had developed. A computed tomography scan demonstrated thickened subcutaneous tissue over the left lumbar region. Excision of necrotic tissue and sequential irrigation using povidone iodine liquid were effective. The patient then underwent chemotherapy for malignant lymphoma at the internal department. Nine months after the operation, the scrotal skin had completely recovered.

Aged↗
PubMed1999

Defective apoptotic signal transduction pathway downstream of caspase-3 in human B-lymphoma cells: A novel mechanism of nuclear apoptosis resistance.

Mitochondria play a central role in controlling apoptosis, and activation of the caspase cascade appears to be crucial event during the apoptotic process. Human B lymphoma Raji cells are resistant to nuclear apoptosis induced by various stimuli. Using this cell line, we have asked whether reduction of the mitochondrial transmembrane potential and activation of caspase-3 are sufficient to induce DNA fragmentation during the apoptotic process. After stimulation with cell-permeable C2-ceramide or mitochondrial permeability transition (PT) inducers, not only apoptosis-sensitive cell lines (HL-60, Jurkat, and Daudi cells), but also Raji cells showed reduction of the mitochondrial transmembrane potential (triangle uppsim), activation of caspase-3, and loss of clonogenic potential. However, Raji cells did not show detectable levels of nuclear apoptosis (DNA degradation). In a cell-free system, cell lysates from tetra-butylhydroperoxide (t-BHP)-treated HL-60 cells induced DNA degradation of Raji nuclei, whereas cell lysates from t-BHP-treated Raji cells failed to induce DNA degradation in either apoptosis-sensitive cell lines or apoptosis-resistant Raji cells. Cleavage of DFF-45, which is a downstream target molecule for caspase-3, was observed in Raji cells as well as in apoptosis-sensitive Daudi cells. These results indicate that there is a defective apoptotic pathway in the cytoplasm downstream of caspase-3 in Raji cells.

Alkylating Agents↗
PubMed1999

Clonal expansion of gammadelta-T lymphocytes in an HTLV-I carrier, associated with chronic neutropenia and rheumatoid arthritis.

We report on an HTLV-I carrier showing clonal proliferation of gammadelta-T lymphocytes associated with chronic neutropenia and rheumatoid arthritis (RA). A 75-year-old Japanese woman had a 20-year history of RA and was found to have neutropenia and lymphocytosis by routine examinations. Her white cell count was 5,800/microl with 89% lymphocytes. The proliferating gammadelta-lymphocytes did not show the typical morphology of large granular lymphocytes (LGL) and were positive for CD3, TCRdelta1, and HLA-DR but negative for CD4, CD8, and deltaTCS1. Clonally rearranged TCRgamma-chain (Jgamma) and TCRbeta-chain (Cbeta1) genes were detected by Southern blot analysis. Clonality of these proliferating gammadelta-T cells was confirmed by CDR3 size analysis for the TCRdelta-chain. Anti-HTLV-I antibody was positive and the pX region of HTLV-I proviral DNA was detected by PCR analysis, but clonal integration of HTLV-I proviral DNA was not detected by Southern blotting analysis. The patient's clinical course has been stable, except for infrequent infectious episodes. The association of HTLV-I/II infection with T-LGL leukemia has been reported by several groups, although most cases exhibit TCRalphabeta+ type T cells. Analysis of the junctional sequence of TCR on T-LGL leukemia cells may clarify the role of HTLV-I/II infection in clonal T-cell proliferation.

Aged↗
PubMed1999

Tall cell variant of papillary thyroid carcinoma with foci of columnar cell component.

We report a case of the tall call variant of papillary thyroid carcinoma with foci of columnar cell component in a 67-year-old Japanese man. Tall cell variant occupied more than 70% of the tumour, and columnar cell component was of two types in representative sections. One showed striking stratification of nuclei with scanty cytoplasm, and the other appeared clear. Characteristic nuclear features of papillary carcinoma were also observed in the area of the tall cell variant. The patient died of the thyroid cancer with aspiration pneumonia 10 years and 6 months after operation. Although autopsy was not performed, metastatic lymph nodes of the neck removed during life also showed papillary carcinoma with both tall cell and columnar cell components. Our case indicates that tall cell and columnar cell variants may coexist in the same tumour although the pathogenesis remains unclear.

Aged↗
PubMed1999

Parasitic nodule of the thyroid in a patient with Graves' disease.

We report a case of a parasitic nodule of the thyroid in a patient with Graves' disease, which mimicked a lymph node metastasis from a primary occult thyroid carcinoma. The patient was a 67-year-old Japanese woman with a past history of subtotal thyroidectomy for Graves' disease, who was referred to our hospital because of a right cervical mass. A lymph node-like lesion measuring 1.5 cm in diameter was palpable, distinct from the remnant of the right thyroid lobe. Thyroid scintigraphy using 123I-Na revealed a hot lesion at the upper lateral portion of the right thyroid lobe, and this was resected. Microscopically, the mass showed thyroid follicles with lymphocytic infiltration and lymphoid follicles. Clear ground glass nuclei, nuclear grooving and intranuclear inclusions were not observed. No morphological evidence of the lymph node was found in the mass by reticulin staining. Parasitic nodules of the thyroid in patients with Graves' disease may mimic a metastatic carcinoma of the thyroid.

Aged↗
PubMed1999

Solid-pseudopapillary carcinoma of the pancreas.

A case of solid-pseudopapillary carcinoma (SPC) of the pancreas in a 34-year-old Japanese woman is presented. An abdominal ultrasonography revealed a mass, which measured 10 cm in diameter, in the body and tail of the pancreas. The tumor was resected and it was originally diagnosed as a non-functioning islet cell tumor. One year and five months later, the patient was re-admitted to hospital, and liver metastasis was confirmed by ultrasonography. The patient died 6 days after the second transcatheter arterial embolization (TAE) required for the metastasis. The autopsy showed small foci of liver metastasis. A retrospective examination of the tumor suggested the diagnosis of SPC because of its characteristic solid and pseudopapillary structures, immunohistochemical findings, and liver metastasis. This case suggests that capsular invasion, specifically found at the surgical margin of the peritoneal side, may be an important pathological finding that is suggestive of malignant potential in solid-pseudopapillary tumor. If there is such a finding in a surgical specimen, an intensive follow up should be advised to the clinician.

Adult↗
PubMed1999

Enteral infusion of sodium 2-ketoisocaproate in endotoxic rats.

OBJECTIVE: In view of our previous finding that the intravenous infusion of 2-ketoisocaproate (KIC) improved survival in septic rats, we endeavored to determine whether the enteral infusion of KIC improves survival in endotoxic rats, and, if so, the mechanism of this effect. SUBJECTS: Eighty-five rats were given 15 mg/kg of Escherichia coli lipopolysaccharide (026:B6). INTERVENTIONS: KIC, sodium pyruvate (PYR), or sodium bicarbonate (HCO3) was infused continuously intragastrically at 18.75 mmol/kg/day. MEASUREMENTS AND MAIN RESULTS: KIC administration increased circulating concentrations of KIC and ketone bodies. Survival rates were: KIC 17/32; PYR 2/22; and HCO3 8/31. The significant improvement in survival with KIC, in contrast with HCO3 (p<.04) or PYR (p<.002), points to an effect specific to KIC rather than to ketoacids generally, and argues against an antioxidant mechanism to explain improved survival with enteral administration. To determine whether altered nitric oxide production was responsible, plasma nitrite plus nitrate concentrations were measured sequentially in rats given a lower dose of lipopolysaccharide plus continuous intragastric KIC, PYR, or HCO3. All rats exhibited pronounced increases in plasma nitrite plus nitrate concentrations, peaking at 8 hrs, but both KIC and PYR caused greater increases than HCO3. Thus, differences in nitric oxide production cannot account for the different effects of PYR and KIC on survival. However, KIC infusion for 8 hrs substantially increased ketone bodies in blood and liver, in comparison with the infusion of HCO3 or PYR. CONCLUSION: Continuous enteral infusion of KIC improves survival in endotoxemia, probably by its conversion to ketone bodies, which serve as an alternative energy substrate.

Animals↗
PubMed1999

Basaloid type adenoid cystic carcinoma of the breast.

We report a case of adenoid cystic carcinoma (ACC) of the breast with a prominent basaloid feature. The patient was a 62-year-old Japanese woman with a right breast mass, measuring 1.5 cm in diameter. Histologically, the tumor was composed of basal cell-like tumor cells, and it was originally diagnosed as invasive ductal carcinoma. The presence of PAS-positive basement membrane material around the tumor cell nests may be a diagnostic clue to ACC. The prognosis of ACC of the breast is considered to be favorable. However, basaloid type ACC may represent a poor prognosis, since our case revealed an aggressive behavior in spite of its small size.

Breast Neoplasms↗
PubMed1999

Bamboo-joint-like appearance of the stomach: a histopathological study.

A bamboo joint-like (BJL) appearance is an endoscopic finding characterized by swollen longitudinal folds transversed by erosive fissures or linear furrows, and it seems to be associated with Crohn's disease (CD). We performed gastroduodenoscopy in 1781 patients, and found BJL lesions in 15 (65.2%) of 23 CD patients and 20 (1.1%) of 1758 non-CD patients. Histological examination of the biopsy specimens showed sharp, fissure-like erosion or mucosal cleft in 7 (50%) out of 14 CD patients and one (20%) out of 5 non-CD patients. All cases with fissure-like erosion or, mucosal cleft revealed lymphoid aggregates, eosinophilic infiltration and edema in the superficial portion of the surrounding lamina propria. Epithelioid granuloma was seen at the base of the fissure-like erosion in two cases with CD. Our results indicated that fissure-like erosion or mucosal cleft in gastric biopsy specimens reflects the BJL appearance, and that such findings may provide a diagnostic clue to CD.

Adult↗
PubMed1999

Intraosseous epithelioid malignant peripheral nerve sheath tumor of the phalanx. Case report.

We report the first case of intraosseous epithelioid malignant peripheral nerve sheath tumor (MPNST) occurring in the phalanx. The patient was a 50-year-old Japanese man with an intramedullary lytic lesion of the proximal phalanx. Microscopically, the tumor was composed of epithelioid cells or polygonal cells, forming large cell nests with central necrosis. Most tumor cells were diffusely and strongly immunopositive for S-100 protein and vimentin, and negative for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, alpha-smooth muscle actin, and HMB-45. Laminin-positive material was discontinuously demonstrated between the individual tumor cells. Electron microscopy showed prominent external lamina. Our case indicated that laminin is useful for differentiating epithelioid MPNST from metastatic carcinoma and malignant melanoma.

Bone Neoplasms↗
PubMed1999

[The thyroid--cytologic findings in connection with histopathology].

Numerous reviews support the use of fine needle aspiration cytology of the thyroid as a simple, accurate, fast, economic, as well as safe method to diagnose thyroid disorders. When aspiration cytology preparations of the thyroid are examined, knowledge of the histopathology is needed. It is also important that the diagnostic criteria of aspiration cytology are different from those of exfoliative cytology. I herein discuss methods to identify aspiration cytological findings of the thyroid, in connection with histopathology.

Biopsy, Needle↗
PubMed1999

[Utilization of the Internet in cytology].

As no standards for morphologic diagnosis exist, it is difficult to establish quality assurance. We discuss utilization of the internet in cytology, including participation in mailing lists, home pages, internet slide conference and data base use. The newest information concerning cytology can be obtained using the internet.

Cytodiagnosis↗
PubMed1999

Late recurrence of acinic cell carcinoma of the parotid gland.

Acinic cell carcinoma of the salivary glands is a rare cancer representing a low grade malignancy. The recurrence of a tumor is sometimes encountered, usually within 5 years of initial operation. We describe an unusual recurrence after a long interval following primary surgery. In 1987, a 60-year-old woman underwent excision of a mass in the superficial lobe of the right parotid gland under the preoperative diagnosis of a benign tumor. A histologic diagnosis of acinic cell carcinoma was made by examining sections from the resected mass. The patient noted several small nodules in the right parotid region in 1995, but she did not visit our clinic until 1998 when tenderness developed. A locally recurrent tumor and cervical lymph nodes containing metastases were resected and postoperative radiotherapy was given 11 years after the first operation. At least 10 years of follow-up may be necessary for patients with acinic cell carcinoma because of slow-tumor growth.

Carcinoma, Acinar Cell↗
PubMed1998

Generation of an inhibitory circuit involving CD8+ T cells, IL-2, and NK cell-derived TGF-beta: contrasting effects of anti-CD2 and anti-CD3.

Although the phenomenon of immunosuppression is well established, the mechanisms involved in the generation of lymphocytes with down-regulatory activity are poorly understood. Unlike anti-CD3 antibodies, mitogenic combinations of anti-CD2 antibodies do not stimulate human PBL to produce IgM or IgG. In determining the reason for this difference, we have found that anti-CD2 triggers an inhibitory circuit facilitated by TGF-beta provided by NK cells. Stimulation of PBL with anti-CD2, but not anti-CD3, generated substantial amounts of active TGF-beta. NK cells were found to be a significant source of TGF-beta and were the only lymphocyte population that constitutively produced this cytokine. Anti-CD2 enhanced the production of active TGF-beta by purified NK cells. TGF-beta. After the removal of NK cells or the addition of anti-TGF-beta, anti-CD2 could stimulate Ig production. Anti-TGF-beta had to be added within the first 24 h for a maximal effect. Moreover, a short, overnight exposure of CD8+ T cells to TGF-beta could prime them for suppressor activity provided that IL-2 was also present. Thus, the presence of active TGF-beta coincident with CD8+ T cell activation can condition these cells to mediate down-regulatory activity, and NK cells can serve as the source of this cytokine.

Adult↗
PubMed1998

Invasive pulmonary mucormycosis with rupture of the thoracic aorta.

We report an acute myelogenous leukemia patient with mucormycosis who died of massive hemoptysis during antifungal therapy. The diagnosis was made postmortem and autopsy revealed that the pulmonary nodule consisting of mucorales protruded over the luminal surface of the aorta. Microscopic examination showed the invasion of mucor hyphae into the wall of the aortic arch. Surgical treatment may be indicated for patients with pulmonary mucormycosis refractory to amphotericin B therapy.

Aorta, Thoracic↗