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Biomedical subjects

M Tanabe

Publications and source records attributed to M Tanabe.

At least 109 records · Page 6Linked to original sources
PubMed1998

Iodine-131 MIBG imaging in multiple endocrine neoplasia type 2B.

A 16-year-old boy had a swollen neck that was a result of multiple endocrine neoplasia Type 2B (MEN 2B). CT revealed bilateral thyroid tumors, swelling of right cervical lymph nodes, and slight enlargement of the right adrenal gland. I-131 metaiodobenzylguanidine (MIBG) scintigraphy demonstrated increased uptake in the right adrenal gland and the left thyroid tumor, but no abnormal uptake in the right thyroid tumor and the right cervical lymph nodes. Postoperative pathologic findings were consistent with the diagnosis of right adrenal medullary hyperplasia, which is a precursor of pheochromocytoma. In patients with MEN 2B, I-131 MIBG scintigraphy in conjunction with CT of the adrenal glands should be performed to determine the disease stage of the adrenal medullae. In the cervical region, the diagnosis was medullary thyroid carcinoma (MTC) in both thyroid tumors and metastases in the right cervical lymph nodes. The right MTC was more aggressive than the left MTC. It is interesting that not all sites of known MTC take up I-131 MIBG to the same degree.

3-Iodobenzylguanidine↗
PubMed1998

Usefulness of Technetium-99m human serum albumin lymphoscintigraphy in chyluria.

Chyluria is a urologic manifestation of a lymphatic system disease abnormality and leads to nutritional deficiency. The case of a patient with chyluria is presented, and the results of lymphoscintigraphy with those of contrast lymphangiography are compared. Lymphoscintigraphy very clearly showed the site of the fistulae and was as precise as lymphangiography. Follow-up lymphoscintigraphy 2 months after therapy revealed no radionuclide accumulation. Lymphoscintigraphy is a useful, noninvasive, safe, and simple technique for the diagnosis and follow-up of chyluria.

Aged↗
PubMed1998

Iodine-123 BMIPP and Ga-67 scintigraphy in liposarcoma.

A patient with recurrent retroperitoneal liposarcoma had multiple suspected metastases. I-123 BMIPP imaging showed areas of increased uptake due to accumulation in the myxoid components of the liposarcoma. Ga-67 showed accumulation in the undifferentiated components. The well-differentiated components showed little accumulation of either I-123 BMIPP or Ga-67. Differences in the accumulation of these radionuclides may reflect differences in cell densities, fatty acid metabolism, and the degree of malignancy. I-123 BMIPP and Ga-67 scintigraphy may be useful in determining the prognosis of liposarcoma.

Abdomen↗
PubMed1998

Influence of the gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases.

To investigate the influence of gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases, the authors examined the mastoid pneumatization among patients with sniffing habit using computed tomography, and also examined the change of negative middle ear pressure induced by sniffing using tympanogram. In 20 ears with cholesteatoma or adhesive otitis media, the areas of mastoid cavity measured at the level of the lateral semicircular canal were significantly smaller than those in 26 ears with otitis media with effusion (OME) or attic retraction and in eight normal ears with sniffing habit (P < .01 and P < .0001, respectively). In 26 ears with OME or attic retraction, the areas of mastoid cavity were significantly smaller than those in eight normal ears with sniffing habit (P < .0001). By contrast, in the four ears with sniff-induced middle ear disease, the recovery of negative middle ear pressure in 5 minutes without swallowing was less than 10 mm H2O, whereas in all seven ears with normal eardrum, negative middle ear pressure recovered by more than 20 mm H2O in 5 minutes. These findings suggested that impairment of gas exchange function through the middle ear mucosa, as well as eustachian tube dysfunction, might be closely related to the development of sniff-induced middle ear diseases.

Adolescent↗
PubMed1998

Expression of MRP and cMOAT in childhood neuroblastomas and malignant liver tumors and its relevance to clinical behavior.

Advanced neuroblastoma and malignant liver tumor are representative childhood cancers for which combined chemotherapy including cisplatin and doxorubicin is routinely performed. The prognosis of patients with tumors which develop multiple drug resistance (MDR) is unfavorable. To elucidate the role of multidrug resistance-associated protein (MRP) and canalicular multispecific organic anion transporter (cMOAT) in the clinical behavior of the tumors, we examined 42 neuroblastomas and 10 malignant liver tumors for the expressions of MRP and cMOAT by quantitative RNA-polymerase chain reaction (PCR). The amplification and expression of N-myc oncogene in the neuroblastomas were also investigated. We found a close association between MRP and N-myc expression in each neuroblastoma sample but no significant relationship between MRP expression and the patients' outcome. The forced expression of N-myc failed to enhance the expression of MRP in N-myc transfected neuroblastoma cell lines. cMOAT was rarely expressed in the neuroblastomas, but was frequently expressed in the malignant liver tumors. The expression of MRP and cMOAT in the childhood liver tumors was more common and higher, especially in advanced cases with a poor outcome, than that observed in normal liver or in 9 hepatocellular carcinomas from adult patients. The enhanced expression of these genes might be characteristic of childhood malignant liver tumors and related to their clinical chemoresistance.

ATP-Binding Cassette Transporters↗
PubMed1998

L-Type Ca2+ channels mediate the slow Ca2+-dependent afterhyperpolarization current in rat CA3 pyramidal cells in vitro.

Single-electrode voltage-clamp recordings were obtained from CA3 pyramidal cells in rat hippocampal organotypic slice cultures, and the slow Ca2+-dependent K+ current or afterhyperpolarization current (IAHP) was elicited with brief depolarizing voltage jumps. The slow IAHP was suppressed by the selective L-type Ca2+ channel antagonists isradipine (2 microM) or nifedipine (10 microM). In contrast, neither omega-conotoxin MVIIA (1 microM) nor omega-agatoxin IVA (200 nM), N-type and P/Q-type Ca2+ channel antagonists, respectively, attenuated this slow outward current. The slow IAHP was significantly reduced by thapsigargin (10 microM), a Ca2+ ATPase inhibitor that depletes intracellular Ca2+ stores, and by ryanodine (10-100 microM), which blocks Ca2+-induced Ca2+ release from intracellular compartments. At this concentration thapsigargin did not modify high-threshold Ca2+ current, which was, however, blocked by isradipine. Thus, in hippocampal CA3 pyramidal cells, Ca2+ influx through L-type Ca2+ channels is necessary to trigger the slow IAHP. Furthermore, intracellular Ca2+-activated Ca2+ stores represent a critical component in the transduction pathway leading to the generation of the slow IAHP.

Animals↗
PubMed1998

Inhibitory effects of apple polyphenol on induced histamine release from RBL-2H3 cells and rat mast cells.

The anti-allergic activities of polyphenol fractions extracted from immature fruits of apple (Rosaceae, Malus sp.) were evaluated by in vitro assays. A crude apple polyphenol (CAP) fraction, which had been obtained from the juice of immature apples by reverse-phase column chromatography, was further purified by LH-20 column chromatography to obtain an apple condensed tannin (ACT) fraction consisting of linear oligomeric epicatechins from the dimer to pentadecamer. ACT strongly inhibited the release of histamine from rat basophilic leukemia (RBL-2H3) cells stimulated by the antigen-stimulation and from rat peritoneal mast cells stimulated by compound 48/80. The IC50 values for histamine release were 30 micrograms/ml and 25 micrograms/ml, respectively. ACT also inhibited hyaluronidase activity and the increase in intracellular free calcium concentration in RBL-2H3 cells stimulated with the antigen. These results suggest that ACT affected early signal transduction including the calcium influx.

Animals↗
PubMed1998

The usefulness of 99mTc-Technegas scintigraphy for diagnosing pulmonary impairment caused by pulmonary emphysema.

X-ray computed tomography (CT) has been used for diagnosis of pulmonary emphysema because it can reveal the morphology of low attenuation areas. Recently, 99mTc-Technegas imaging, one of several types of scintigraphic techniques, has been used for ventilation scintigraphy. Technegas scintigraphy was performed on 15 patients with pulmonary emphysema, and we compared the extent and degree of abnormal findings on Technegas scintigraphy with the extent of low attenuation areas shown by CT. We classified the findings of Technegas imaging into three grades, from mild to severe, according to the extent of peripheral irregularity and central hot spot formation. We also classified the findings of CT as centrilobular emphysema into three grades from mild to severe according to the extent of low attention areas in the peripheral lung fields. In 5 cases, CT and Technegas assessment resulted in equivalent diagnoses. In eight cases, Technegas images showed more detailed findings than CT images. In the two remaining cases, which were diagnosed as panlobular emphysema on CT, Technegas images showed the severe stage. Technegas scintigraphy was useful for diagnostic assessment of pulmonary emphysema, especially for panlobular emphysema, which is difficult to distinguish from the normal lung condition by CT assessment.

Adult↗
PubMed1998

Impaired tumorigenicity of IL-4-producing murine neuroblastoma cells in immunodeficient nude mice.

We have examined antitumor effect of murine neuroblastoma cells (C1300) retrovirally transduced with interleukin-4 (IL-4) gene in syngeneic A/J and nude mice. Although in vitro proliferation of IL-4-secreting C1300 cells (C1300/IL-4) was not different from that of wild-type cells, the in vivo tumor growth of C1300/IL-4 cells subcutaneously inoculated into immunocompetent A/J mice was retarded compared with that of wild-type cells and consequently, the survival of the A/J mice which received C1300/IL-4 cells was prolonged. In immunodeficient nude mice we observed accelerated growth rate of wild-type tumors in comparison with the tumors developed in A/J mice. In contrast, the tumor growth of C1300/IL-4 cells in nude mice was significantly suppressed and the growth was much slower than that of C1300/IL-4 cells inoculated in A/J mice. Thus, the secretion of IL-4 from tumor cells produced antitumor effect more efficiently in mature T cell-defective hosts than in immunocompetent mice. Our results suggest a possible clinical application of IL-4 expression in tumor cells via genetic manipulations especially in immunocompromised cancer patients.

Animals↗
PubMed1998

Antitumor vaccine effect of irradiated murine neuroblastoma cells producing interleukin-2 or granulocyte macrophage-colony stimulating factor.

We have examined vaccination effects of cytokine-producing murine neuroblastoma cells (C1300). C1300 cells retrovirally transduced with interleukin-2 (IL-2) or granulocyte macrophage-colony stimulation factor (GM-CSF) gene were established. Their in vitro proliferation rates and the class I expression of major histocompatibility complex were not different from those of wild-type cells. Five-Gy irradiation of the respective cytokine producers slightly reduced the in vitro cell growth but treatment with 15 Gy significantly impaired the proliferation. In contrast, the secretion of both cytokines from the respective transduced cells was retained compared with the cell growth. We immunized syngeneic mice with irradiated wild-type cells as a control or cytokine-producing cells and challenged the mice with unirradiated wild-type cells. The control mice developed tumors of the challenged wild-type cells, on the contrary, the mice which had received irradiated IL-2 or GM-CSF producers did not. Thus, IL-2- or GM-CSF-expressing syngeneic tumor cells can be potentially used as a tumor vaccine by inducing protective immunity against low immunogenic neuroblastomas in the inoculated hosts.

Animals↗
PubMed1998

Cause of posterior canal wall retraction after surgery from the viewpoint of mastoid conditions.

OBJECTIVE: To determine the relationship between preservation of the mastoid mucosa during ear surgery and retraction of the attic or posterior wall of the external auditory canal (EAC) and mastoid aeration after surgery. METHODS AND DESIGN: Retraction of the posterior EAC wall and mastoid aeration were evaluated after surgery in 48 individuals (50 ears) with cholesteatoma, adhesive otitis media, or chronic suppurative otitis media, in whom the posterior bony EAC walls were removed with or without preservation of mucosa and reconstructed with soft tissues alone (EAC skin and temporal fascia) during surgery. RESULTS: Postoperative computed tomography showed that in ears with notable retraction of the posterior EAC wall appearing like an open mastoid cavity, there was no air in the mastoid, whereas in ears with no or only slight retraction there was computed tomographic evidence of mastoid aeration. Second, notable retraction of the posterior EAC wall occurred in a significantly smaller percentage of ears in which at least the epitympanic mucosa had been able to be preserved during surgery than in those that had undergone removal of all mucosa (mastoidectomy). CONCLUSIONS: These results indicate that 1) preservation of epitympanic mucosa during surgery is an important factor for prevention of retraction of the posterior EAC wall and for reaeration of the mastoid after surgery, and 2) the intact canal wall technique seems to be indicated whenever at least the epitympanic mucosa can be preserved, and when no mucosa can be preserved the canal wall down procedure seems to be indicated.

Adult↗
PubMed1998

Comparative study of technetium-99m-sestamibi and thallium-201 SPECT in predicting chemotherapeutic response in small cell lung cancer.

UNLABELLED: The purpose of this study was to evaluate the relationship between 99mTc-sestamibi (MIBI) accumulation by tumor and response to chemotherapy in small cell lung cancer patients compared with 201TI-chloride. METHODS: There were 19 patients with small cell lung cancer just before chemotherapy initiation. The patients were classified by a follow-up CT into complete remission, partial remission and no change groups. All patients underwent dual-isotope imaging with 201TI-chloride and 99mTc-MIBI. Regions of interest were placed over the tumors and contralateral normal lung tissue on one coronal view with a clearly defined lesion, and the tumor-to-normal (T/N) ratio and retention index were calculated. RESULTS: Early and delayed T/N ratios for 99mTc-MIBI in complete remission and partial remission groups were significantly higher (p < 0.05) than in the no change group. There was no significant correlation between T/N ratio and tumor response using 201TI-chloride. There were no significant differences in the retention index with respect to the tumor response in both 201TI-chloride and 99mTc-MIBI SPECT images. CONCLUSION: Technetium-99m-MIBI SPECT may be more effective than 201TI-chloride SPECT for evaluating response to chemotherapy in patients with small cell lung cancer.

Adult↗
PubMed1997

Efficacy of intraportal infusion of prostaglandin E1 to improve the hepatic blood flow and graft viability in porcine liver transplantation.

BACKGROUND: Prostaglandin E1 (PGE1) has been reported to have a protective effect in experimental and clinical models of liver damage. The aim of this study was to elucidate the effects of the intraportal infusion of PGE1 on hepatic blood flow and graft viability after orthotopic liver transplantation in pigs. METHODS: First, the hepatic arterial flow (HAF), portal venous flow (PVF), and liver tissue blood flow (LTBF) were measured during the continuous intravenous or intraportal infusion of PGE1. Second, two groups of pigs underwent orthotopic liver transplantation: group A, untreated controls; and group B, animals that received intraportal PGE1 for 2 hr after vascular reconstruction of the allograft. Changes in HAF, PVF, LTBF, and hepatic function were measured. RESULTS: The intraportal infusion of PGE1 significantly increased HAF and had no effect on blood pressure, PVF, or LTBF. In group B, HAF and LTBF increased significantly with time. In group A, HAF remained unchanged and a decrease in LTBF was observed. Group B exhibited a higher arterial ketone body ratio and a greater bile flow compared with group A. A significant elevation in serum glutamic oxaloacetic transaminase concentration was observed in group A, but not in group B. CONCLUSIONS: This study demonstrates that the intraportal infusion of PGE1 improves hepatic allograft blood flow, predominantly through an effect on HAF, and may improve graft viability after orthotopic liver transplantation.

Alprostadil↗
PubMed1997

Different thresholds in the responses of two heat shock transcription factors, HSF1 and HSF3.

Avian cells express three HSF genes encoding a unique factor, HSF3, as well as homologues of mammalian HSF1 and HSF2. HSF1 is the major factor that mediates the heat shock signal in mammalian cells. We reported previously that cHSF3, as well as cHSF1, is activated by heat shock in chicken cells. In this study, we examined the functional differences between cHSF1 and cHSF3. Comparison of the heat-inducible DNA binding activity of cHSF1 with cHSF3 at various temperatures revealed that the latter was activated at higher temperatures than the former. At a mild heat shock, such as 41 degrees C, only cHSF1 was activated, whereas both cHSF1 and cHSF3 were activated following a severe heat shock at 45 degrees C. Heat-inducible nuclear translocation and trimerization were accompanied by DNA binding activity. We also observed that cHSF3 was activated by treating cells with higher concentrations of sodium arsenite compared to cHSF1. The DNA binding activity of cHSF3 by severe heat shock lasted for a longer period than that of cHSF1. Interestingly, the total amount of cHSF3 increased only upon severe heat shock, whereas that of HSF1 decreased. Substantial amounts of cHSF3 remained in the soluble fraction under severe heat shock, whereas cHSF1 rapidly moved to the insoluble fractions in that conditions. Comparison of transcriptional activity of the activation domains of cHSF1 and cHSF3 revealed that the activity of cHSF3 was as strong as that of cHSF1. These findings indicate that there are different thresholds for cHSF1 and cHSF3 and that cHSF3 is involved in the persistent and burst activation of stress genes upon severe stress in chicken cells. Pretreatment of cycloheximide elevated the threshold concentrations of arsenite of both factors. This suggests that denaturation of nascent polypeptides could be the first trigger for the activation of both factors, and the pathways for activation of cHSF1 and cHSF3 may be identical, or at least share some common mechanisms.

Animals↗
PubMed1997

Gas exchange function of the middle ear in patients with otitis media with effusion.

Gas exchange function through the middle ear mucosa was assessed using nitrous oxide (N2O) in patients with otitis media with effusion (OME), as well as in normal ears during elective surgery for unrelated disorders. In all normal ears except one (n = 43), an increase in pressure was observed after N2O inhalation. In 42 of 84 ears with OME, a pressure increase was observed, but not in the remaining 42 ears (50%), indicating that the gas exchange function in these latter ears was impaired. In 21 of the 42 ears showing no middle ear pressure increase following N2O inhalation, the middle ear pressure was again monitored after myringotomy and aspiration of the effusion A pressure increase was found in 16 ears, indicating that the impairment in gas exchange function in ears with OME may be reversible in most cases. Computed tomography of the mastoid was examined preoperatively in 66 ears, with the presence or absence of a middle ear pressure change well correlated in 57 ears with the presence or absence of mastoid aeration.

Adolescent↗