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Biomedical subjects

S Mitsudo

Publications and source records attributed to S Mitsudo.

At least 19 recordsLinked to original sources
PubMed2005

Experimental observation of the 1/3 magnetization plateau in the diamond-chain compound Cu3(CO3)2(OH)2.

The magnetic susceptibility, high field magnetization, and specific heat measurements of Cu3(CO3)2(OH)2, which is a model substance for the frustrating diamond spin chain model, have been performed using single crystals. Two broad peaks are observed at around 20 and 5 K in both magnetic susceptibility and specific heat results. The magnetization curve has a clear plateau at one third of the saturation magnetization. The experimental results are examined in terms of theoretical expectations based on exact diagonalization and density matrix renormalization group methods. An origin of magnetic anisotropy is also discussed.

Journal Article↗
PubMed2003

Small cells in hepatoblastoma lack "oval" cell phenotype.

Hepatoblastoma, a childhood tumor of the liver, is composed of epithelial and mesenchymal elements in varying proportions and at various stages of differentiation. The epithelial element recapitulates the stages of hepatocyte development from the primitive blastema through embryonal hepatocytes to fetal hepatocytes. The blastemal or undifferentiated cells have been postulated to represent neoplastic hepatocyte progenitor cells. In this study, we examine the immunophenotype of the various epithelial cells of hepatoblastoma with special emphasis on the small undifferentiated cell component and compare it with that of adult hepatocytes and hepatic stem (oval) cells. Putative stem cells in the liver can express all of the following markers: alpha-feto protein, CK19 (OV-6), chromogranin A, Bcl-2, HepPar-1, and alpha1 microglobulin. The latter, like alpha-feto protein, is a plasma protein synthesized by hepatocytes. Both alpha1 microglobulin and HepPar-1 are expressed in fetal liver cells as early as 7 weeks of intrauterine life. They are also expressed in hepatocellular carcinoma and in hepatocytic cell lines derived from normal fetal or adult liver. Formalin-fixed, paraffin-embedded archival tissues from 10 predominantly epithelial hepatoblastomas were immunostained with antibodies directed against CD 34, alpha1 microglobulin, Bcl-2, HepPar 1, and CK19 using the avidin-biotin-peroxidase method. The undifferentiated small cell component did not express any of the markers studied, namely, Bcl-2, HepPar-1, alpha(1) microglobulin, CD34, or CK19. Hepatocyte-like cells were alpha1 microglobulin- and HepPar-1-positive, with the intensity of staining correlating with the degree of hepatocytic differentiation. Bcl-2 expression was restricted to areas of ductular differentiation. CK19 was detected in foci that showed duct formation. The small cells of hepatoblastoma did not express HepPar-1, Bcl-2, CK19, alpha1 microglobulin, or CD34, markers that characterize the immunophenotype of hepatic stem cells ("oval" cells). Thus, this observation raises the following questions: (1) is "hepatoblastoma" a misnomer? (2) is the expression of tumor antigens dysregulated in hepatoblastoma? (3) does the liver have two different types of progenitor cells, oval cells and blastemal cells, with differing immunophenotypes? and (4) do the blastemal cells, rather than oval cells, represent the more primitive progenitor cells of the liver?

Cell Differentiation↗
PubMed1998

Comparison of sonograms and liver histologic findings in patients with chronic hepatitis C virus infection.

Gray scale ultrasonographic images of the liver were correlated with histologic findings in patients with chronic hepatitis C virus infection. The gray scale patterns of 64 livers with chronic hepatitis C virus infection were categorized as normal, fatty, fibrofatty, fibrotic, or inflammatory and were graded as mild, moderate, or severe. Liver biopsy specimens also were analyzed for the presence of fat, inflammation, and fibrosis and graded similarly. No correlation was found between fatty and fibrofatty sonographic findings with any of the three histologic patterns. Correlations were found between fibrotic sonographic findings and both fibrotic and inflammatory histologic findings (r = 0.27; P = 0.03). Although some pathologic features of liver disease were detected by ultrasonography, no useful correlation was noted between results of sonography and histologic examination.

Adolescent↗
PubMed1996

Paecilomyces sinusitis in an immunocompromised adult patient: case report and review.

A case of fungal sinusitis caused by Paecilomyces lilacinus that was unresponsive to amphotericin B and involved a patient with acute myeloid leukemia is described. Histologic examination of sinus tissue and periorbital bone demonstrated invasion by a fungus with septate hyphae, which was identified in culture as P. lilacinus. The isolate was resistant to amphotericin B but susceptible to itraconazole. The patient responded clinically when itraconazole was added to the treatment regimen. Invasive aspergilar infections are frequently diagnosed by histology. Other fungi such as Fusarium, Pseudallescheria, and Paecilomyces species also produce hyphae in tissue and can be confused with Aspergillus species. However, these pathogens may be resistant to amphotericin B. Since alternative therapy is now available for infections with some of the amphotericin B-resistant fungi, such as P. lilacinus, every effort should be made to recover the fungal pathogen so that effective treatment can be administered.

Acute Disease↗
PubMed1993

Detection of a deep lipoblastoma by MRI and ultrasound.

Lipoblastoma is a rare benign tumor of the soft tissue occurring predominantly during the first two years of life. We report here the application of MRI and ultrasound to the detection of a soft tissue lipoblastoma. By MRI and ultrasound, we precisely evaluated the extent of the tumor, the presence of atypical areas of cystic and mucoid degeneration within the tumor, and its lack of vascularity. Our patient's lipoblastoma did not demonstrate the signal characteristics of a fatty tumor on MRI.

Humans↗
PubMed1992

Pathology of intestinal ischemia.

Intestinal ischemia produces a spectrum of gross and microscopic pathologic changes that range from transmural necrosis to reversible mucosal injury. Depending on the stage at which tissue is examined, findings may reflect the acute injury or reparative changes. This article reviews the diagnosis of the pathologic findings in differential intestinal ischemia.

Diagnosis, Differential↗
PubMed1991

Colonic ischemia complicating immunotherapy with interleukin-2 and interferon-alpha.

Colonic ischemia (CI) is a rare complication of high-dose interleukin-2 (IL-2) immunotherapy. This complication occurred in three of 141 patients (2.1%) with metastatic cancer treated with high-dose IL-2 therapy; CI only developed in patients receiving interferon-alpha (IFN) with IL-2 (three of 21, 14%) compared with none of 120 in those patients receiving IL-2 alone (P equals 0.0009). Severe diarrhea (greater than or equal to 7 bowel movements/day) also was significantly more common in patients receiving IFN with IL-2 (six of 21, 29%) than in those receiving IL-2 alone (three of 120, 2.5%, P equals 0.001) and preceded the clinical diagnosis of CI in all three patients. Three of nine patients with severe diarrhea had CI. Hematochezia occurred in four patients, all of whom received IFN with IL-2; three had CI, and the other patient had nonspecific colitis. Differences in vasopressor use did not explain the increased risk of CI in patients receiving IFN; those receiving IFN with IL-2 required phenylephrine less often than patients receiving IL-2 alone (P equals 0.01). The administration of lymphokine-activated killer (LAK) cells had no significant effect on the incidence of CI, severe diarrhea, peritonitis, or vasopressor use; two of three patients with CI, however, had their ischemic episode within 24 hours after the last of three LAK cell infusions. In conclusion, CI is an unusual complication of high-dose IL-2 and IFN immunotherapy. In patients receiving such combination therapy, severe diarrhea is a risk factor for the subsequent occurrence of CI.

Carcinoma, Renal Cell↗
PubMed1991

Complete remission in refractory anaplastic adult Wilms' tumor treated with cisplatin and etoposide.

A 61-year-old woman underwent a left radical nephrectomy for Stage II anaplastic Wilm's tumor. She received no adjuvant therapy. One year later computerized tomography (CT) of the abdomen revealed a mass in the left renal fossa and retroperitoneal adenopathy. A CT-guided needle biopsy was nondiagnostic. The patient had progressive disease after treatment with dactinomycin, doxorubicin, and vincristine, but achieved a complete response after treatment with cisplatin and etoposide. The therapy of Wilms' tumor in adults is discussed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Natural killer cell activity in a rat model of amiodarone-induced interstitial lung disease.

The role of lymphocytes in the pathogenesis of amiodarone-induced lung disease is controversial. Increases in the percentages of lymphocytes in bronchoalveolar fluid of both patients and animals with amiodarone pulmonary toxicity have been reported. To assess whether these lymphocytes are functionally activated, we measured natural killer cell activity in the lungs and blood of rats with amiodarone-induced pulmonary toxicity. Amiodarone treated rats exhibited pathologic evidence of amiodarone-induced lung disease after one week of treatment and this injury was sustained and more extensive during the remainder of the study period. Control rats had histologically normal lungs. Blood NK activity was equally present in both amiodarone-treated and control groups and was not significantly different over the course of the study (16 +/- 3 percent and 13 +/- 2 percent, respectively; p greater than 0.05). Thus, NK cells were activated only in the lungs of rats treated with amiodarone, suggesting a local immune response in the lung. These data support the concept that lymphocytes play an important role in the pathogenesis of amiodarone-induced lung disease.

Amiodarone↗
PubMed1989

Lung lymphocytes in bleomycin-induced pulmonary disease.

Previous studies have not clearly defined the role of cell-mediated immunity in bleomycin-induced lung injury. In this report the functional activity of T lymphocytes obtained from minced lung preparations, bronchoalveolar lavage, and blood of rabbits treated with bleomycin was examined in cell proliferation and cell-mediated cytotoxicity assays. Four days after instillation of bleomycin (10 units/kg) into the right lung, histologic examination revealed mononuclear cell interstitial infiltrates and alveolar exudates. Right lung bronchoalveolar lavage (BAL) cell counts were similar in both groups, but the percentage of lymphocytes and neutrophils was elevated in bleomycin-treated groups (25% vs. 7% and 35% vs. 0% respectively; p less than 0.05). Spontaneous proliferation of cultured BAL and blood lymphocytes was similar in bleomycin-treated rabbits and controls. After 24 h of incubation with interleukin-2 (IL-2), BAL lymphocytes from bleomycin-treated rabbits had nearly a 4-fold greater proliferative response than lymphocytes from untreated rabbits. Concanavalin-A-dependent cell-mediated cytotoxicity (CDCMC) assays were performed to evaluate cytolytic lymphocyte activity. Spontaneous CDCMC activity was not detected in BAL fluid or in blood lymphocytes from either treated or control animals. After 24 h of incubation with IL-2, significant CDCMC activity was detected in lung lymphocytes from bleomycin-treated animals, but not in lung lymphocytes from control animals. These results indicate that stimulated lymphocytes are present in the lungs of rabbits 4 days after exposure to bleomycin.

Animals↗
PubMed1989

Posterior septal and right free-wall Kent pathways visualized in situ and removed at operation.

This article describes the first posterior septal and first and second right free-wall pathways identified at operation for Wolff-Parkinson-White syndrome and confirmed histologically. All pathways were found in the areas of preexcitation identified by pre and intraoperative mapping. They bridged the atrium and ventricle, and postoperative electrophysiological testing confirmed division of the pathways. Kent bundles may be identified at the time of surgery but they appear to be gossamer structures usually destroyed during surgical manipulation of the coronary sulcus. Visualization of the suspected bypass tract should not alter or limit the extent of surgical dissection.

Biopsy↗
PubMed1989

Central nervous system pathology in pediatric AIDS: an autopsy study.

The neuropathologic findings of brains and spinal cords removed at autopsy from 26 infants and children with AIDS is described; in two cases, only the spinal cords were available. The most common finding in the brains was dystrophic calcification of blood vessels of all calibers in the basal ganglia and deep cerebral white matter (21 og 24 cases). The next most frequent finding was subacute encephalitis (SE) (15 of 24 cases) with microglial nodules and multinulceated giant cells. Immunocytochemical and in situ hybridization studies showed HIV antigen or genetic sequences only in the brains of cases with SE. Multinucleated giants cells (MGC) were the most frequent cells with reaction products. MGC were labeled with ricinus lectin (RCA), but not with leukocyte common antigen (LCA) or glial fibrillary acidic protein. Many cells in microglial nodules were labeled with RCA, but not LCA; cells in the perivascular compartment were labeled with LCA, but not RCA. Corticospinal tract degeneration was noted in 15 of 20 spinal cords. In six cases tract degeneration was consistent with delayed myelination, and the remaining cases had axonal injury consistent with Wallerian degeneration. Opportunistic infections were rare (three cases). Central nervous system lymphoma occurred in three children and was the most common mass lesion. In two cases lymphoma occurred in the setting of a systemic polyclonal immunoproliferation possibly related to Epstein-Barr virus infection. Cerebrovascular accidents were noted in seven cases. Two cases had hemorrhage associated with immune thrombocytopenia; one hemorrhage was catastrophic. Two children had large vessel arteriopathy with multiple encephalomalacias. Two children had a necrotizing encephalopathy with encephalomalacia and vascular changes suggestive of a mitochondrial cytopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1987

Nasopharyngeal teratoma in the neonate.

Nasopharyngeal teratomas are rare neoplasms, often presenting as neonatal airway obstruction. A case is presented of a full-term neonate with a mass which filled the oropharynx, nasopharynx and the entire left nasal cavity and extended through the left nares. Airway obstruction necessitated orotracheal intubation immediately after delivery. Cerebrospinal fluid rhinorrhea was suggested and computerized tomography was initially interpreted as a nasoethmoidal encephalocele. After a craniotomy failed to reveal a dural defect, the mass was completely removed via the nose and nasopharynx. The infant was extubated and had an uneventful recovery. This case illustrates the problem of confusing a teratoma for an encephalocele and demonstrates a pitfall in the interpretation of computerized tomography of these lesions.

Diagnosis, Differential↗
PubMed1986

Cytomegalovirus colitis in acquired immune deficiency syndrome: radiologic spectrum.

Six cases of cytomegalovirus (CMV) colitis are described. The radiographic manifestations of this colitis are nonspecific and usually mimic the findings of ulcerative colitis with diffuse mucosal ulceration or granulomatous colitis with aphthous ulceration and skip areas. Terminal ileal involvement was noted in 1 patient. Nonspecific edema was present in 2 other cases. One patient demonstrated unusual cecal and ascending colonic nodularity due to pseudomembranes and, in another, large, flat discrete ulcerations were identified. Angiography, in 1 case, demonstrated marked hypervascularity and identified a site of hemorrhage in the ascending colon. With the radiographic identification of colitis in an immunocompromised patient, particularly a patient with acquired immunodeficiency syndrome (AIDS), CMV colitis must be strongly considered in the differential diagnosis. Endoscopic biopsy is the most effective method of establishing the diagnosis.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Simulation of colonic carcinoma by ischemia.

Nine cases of colonic ischemia are presented in which an initial diagnosis of carcinoma was made from roentgenographic, endoscopic, or intraoperative appearance of the lesion. The clinical features were insufficient to differentiate colonic ischemia from carcinoma. In 7 patients a barium enema was interpreted as, or consistent with, carcinoma. In 3 of these patients colonoscopy also suggested malignancy. In 2 patients, endoscopy suggested a neoplasm but no barium enema was performed. Endoscopic biopsies when performed were negative for malignancy. Three patients were considered to have cancer from the gross appearance of the lesion at laparotomy. Routine use of both barium enema and colonoscopy in patients with suspected colonic neoplasms will usually identify the ischemic nature of lesions incorrectly diagnosed by one technique or the other. In the uncommon patient in whom both studies suggest a neoplasm, but biopsy specimens are negative for tumor, repeat studies 7-10 days later may identify the evolving nature of ischemic lesions and obviate the need for surgery. When no changes are seen, prompt laparotomy is indicated.

Aged↗