Biomedical subjects

N Shikama

Publications and source records attributed to N Shikama.

29 records · Page 2Linked to original sources

PubMed1998

Relationship of 31P MR spectroscopy to the histopathological grading of chronic hepatitis and response to therapy.

PURPOSE: In vivo phosphorus-31 MR spectroscopy (31P MRS) was performed in the human liver in order to investigate the relation between: the ratios of phosphorus metabolites in the liver; the histopathological grading of chronic hepatitis; and the response to therapy. MATERIAL AND METHODS: Hepatic 31P MRS using the DRESS method (depth-resolved surface-coil spectroscopy) was carried out in 45 patients with chronic viral hepatitis or autoimmune hepatitis, and in 16 control subjects. We measured the ratios of the peak areas of phosphomonoesters (PME), inorganic phosphate (Pi), or phosphodiesters (PDE) to the peak area of beta-adenosine triphosphate (ATP). RESULTS: The PDE/ATP ratio of patients with chronic hepatitis or liver cirrhosis was lower than that of control subjects (liver cirrhosis = 0.74; chronic active hepatitis = 1.13-1.21; normal = 1.43); only a small difference was found in the PME/ATP and Pi/ATP ratios. There was no correlation between the spectra and histopathological grading or response to therapy, but the response to therapy was poor when a reduced PDE/ATP ratio was present. CONCLUSION: The PDE/ATP ratio measured by 31P MRS makes it possible to identify the transition of chronic active hepatitis into liver cirrhosis with a poor response to therapy.

Adenosine Triphosphate↗

PubMed1997

Treatment for non-Hodgkin's lymphoma (stage I, II) of the elderly: usefulness of local and regional irradiation and reduced dose chemotherapy.

PURPOSE: To examine the usefulness and safety of a new treatment regimen consisting of irradiation to the involved area and adjacent lymph node area, and reduced dose chemotherapy for elderly patients with non-Hodgkin's lymphoma. METHODS AND MATERIALS: The core of this study was 38 elderly patients older than 65 years old with intermediate or high grade non-Hodgkin's lymphoma, and concomitantly suffering from some other geriatric disease. They received involved area irradiation (40 Gy), adjacent lymph node irradiation (30 Gy), and reduced dose chemotherapy (two cycles of 50-70% ACOP: Doxorubicin, Cyclosphosphamide, Vincristine, Prednisone or 70% MACOP-B: Doxorubicin, Cyclophosphamide, Vincristine, Methotrexate, Bleomycin, Prednisone for 4 weeks). RESULTS: The completion rate of the treatment regimen was 100%. The 5-year local control rate was 98%. The 5-year disease-free survival rate and the 5-year cause-specific survival rate for all patients were 70 and 82%, respectively. No treatment deaths were observed, and the rate of serious complications arising from the treatment was 3%. CONCLUSIONS: The newly conducted treatment regimen proved to be safe and useful for elderly patients with non-Hodgkin's lymphoma concomitantly suffering from some other geriatric disease.

Aged↗

PubMed1997

Clinical stage IE primary lymphoma of the nasal cavity: radiation therapy and chemotherapy.

PURPOSE: To determine the appropriate radiation therapy and chemotherapy for primary lymphoma of the nasal cavity to improve the local control and survival rates. MATERIALS AND METHODS: Of the 25 adult patients with stage IE nasal lymphoma, nine underwent local radiation therapy alone and 16 underwent radiation therapy and chemotherapy (intravenous infusion). Radiation doses to the involved area were 22-54 Gy (median dose, 49 Gy). RESULTS: The 5- and 10-year cause-specific survival rates were 91% and 73%, respectively. The 5- and 10-year disease-free survival rates were 83% and 59%, respectively. Eight patients developed recurrent disease: six at the local site, one in the cervical nodes, and one in the small intestine. Five of the six patients with local recurrence received less than 50 Gy. Four of the six patients developed recurrent disease in the treated area; the other two patients developed marginal recurrences. Prognostic factors such as age, sex, maximum tumor size, and lactate dehydrogenase level were of limited value. CONCLUSION: The most common recurrence site was the local site. To improve the local control rate, the involved area should be treated with high-dose radiation therapy. The clinical results did not demonstrate the usefulness of combination chemotherapy for stage IE nasal lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Changes in the expression of genes involved in protein synthesis during Drosophila aging.

A characteristic feature of aging organisms is their loss in homeostatic functions, including the ability of protein synthesis and turnover. It has been proposed that in senescent Drosophila melanogaster the peptide synthesis elongation factor (EF) EF-1 alpha may become limiting and be responsible for the age-related decline in protein synthesis. We have determined the expression levels of EF genes in Drosophila and have compared them with the expression of several other genes involved in the protein synthesis pathway. Steady-state levels of mRNAs for EF-1 alpha F1 and F2, of mRNAs for four ribosomal proteins, of total poly A+ RNA, rRNA, and tRNA were measured. We show that most RNAs studied decrease immediately after eclosion. There is no evidence for EF-1 alpha mRNA becoming limiting in old flies. Our data suggest that down-regulation of RNA polymerase I-, II-, and III-mediated transcription may contribute to an age-related decrease in protein synthesis or other homeostatic functions.

Aging↗

PubMed1996

Effect of the duration of fasting on myocardial fluorine-18-fluorodeoxyglucose positron emission tomography images in normal males.

To evaluate the effect of the duration of fasting on myocardial fluorine-18-fluorodeoxyglucose (FDG) uptake and distribution, 16 FDG-positron emission tomography (PET) studies were performed in 7 normal volunteers under three different conditions: glucose loading, 6 h fasting and overnight fasting. In the glucose-loaded condition, all subjects had good image quality, and myocardial metabolic rates of glucose (MRGlc) were significantly higher than those in the other two conditions. In the 6 h and overnight fasting conditions, image qualities varied according to MRGlc. Although there were visually distinct regional differences with MRGlc ranging from 0.05 to 0.15 mumol/min per g, these differences were not impressive by a quantitative analysis. The ranges of MRGlc in these two fasted conditions overlapped each other. There was a significant negative linear correlation between MRGlc and serum free fatty acid levels. Thus, MRGlc and image quality in fasted normal subjects varied with the extent of the fed-to-starved transition under clinical fasting conditions (6 h to overnight), and this transition does not depend solely on the duration of fasting. These findings may explain the heterogeneity in FDG studies under fasting conditions.

Adult↗

PubMed1995

Simplified PET quantitation of myocardial glucose utilization.

UNLABELLED: The purpose of this study was to validate experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using 14C-deoxyglucose and assess its clinical feasibility for myocardial PET. METHODS: To validate the BRI method, glucose utilization in myocardial and skeletal muscle was studied in rats with 14C-deoxyglucose after increasing doses of oral glucose loading. To assess clinical feasibility of the method, the BRI was applied to nine patients undergoing myocardial PET and compared to rMGU measured by the deoxyglucose model of Sokoloff et al. and by Patlak graphical analysis. The normal range of myocardial FDG uptake expressed as the BRI was estimated with four normal volunteers. RESULTS: In skeletal muscle, a dose-dependent increase of glucose utilization was observed during oral glucose loading with doses up to 4 mg/g. In the myocardium, glucose utilization increased with a glucose loading dose of up to 1 mg/g without increasing further at greater glucose doses. Ratios of maximal glucose utilization in glucose-loaded rats to 19-hr fasted rats (controls), expressed as the BRI for left and right ventricular myocardium and skeletal muscle were 4.16, 3.74 and 7.39, respectively. Glucose utilization of right ventricular myocardium was approximately 70% of left ventricular myocardium for all glucose-loaded conditions. For patients, the BRI correlated with rMGU; four of these patients had a constant plasma glucose concentration. CONCLUSION: Myocardial BRI is a sensitive indicator of rMGU that does not require dynamic data acquisition or constant plasma glucose concentrations.

Animals↗

PubMed1994

Protein synthesis elongation factor EF-1 alpha expression and longevity in Drosophila melanogaster.

It has been proposed that the decline in protein synthesis observed in aging organisms may result from a decrease in elongation factor EF-1 alpha. Transgenic Drosophila melanogaster flies carrying an additional copy of the EF-1 alpha gene under control of a heat-inducible promoter have an extended lifespan, further indicating that the EF-1 alpha gene may play an important role in determining longevity. To test this hypothesis, we have quantitated EF-1 alpha mRNA, EF-1 alpha protein, and the EF-1 alpha complex-formation activity in these transgenic flies. Furthermore, we have tested whether the transgene construct is functional--i.e., whether transgenic mRNA is induced when flies are grown at higher temperature. The results show that although there is a clear difference in mean lifespan between the EF-1 alpha transgenic (E) flies and the control transgenic (C) flies, E flies do not express more EF-1 alpha protein or mRNA than C flies kept at the same experimental conditions. Although the transgene can be induced when E flies are heat-shocked at 37 degrees C, transgenic mRNA is not detectable in E flies aged at 29 degrees C. In both lines, the loss in catalytic activity with age is the same. We conclude that the E flies examined here do not live longer because of overexpressing the EF-1 alpha gene.

Animals↗

PubMed1992

[Radiation therapy of intracranial germinoma].

The appropriate radiation dose and field for the treatment of intracranial germinoma were investigated in 33 patients. Recurrences were observed in 4 cases treated with local field irradiation only, and all of them were recognized at the margin of the radiation field or under the dose (less than 25 Gy) area. This suggests that whole cranial irradiation (dose of 25 to 30 Gy) should be added even if the tumor is solitary. The effective dose for cerebrospinal dissemination appears to be 25-35 Gy, but prophylactic CNS irradiation seems unnecessary for patients who have not undergone surgical procedures. Changes in mental status were seen in 5 patients (26.3%). Doses of over 59 Gy may be related to this complication.

Adolescent↗

PubMed1992

Immunochemical studies and complete amino acid sequence of the streptokinase from Streptococcus pyogenes (group A) M type 12 strain A374.

The complete amino acid sequence of the streptokinase (SKase) of Streptococcus pyogenes M type 12 strain A374, isolated from a patient with poststreptococcal glomerulonephritis (PSGN), was determined. The epitope domain for the monoclonal antibody N-59, which cross-reacts with SKases of both the PSGN-associated strain and S. equisimilis H46A (a non-PSGN-associated strain), was predicted to be localized in residues 370 to 374. The epitope domain specific for monoclonal antibody RU-1, which reacts only with the PSGN-associated SKase, was localized to residues 164 to 236.

Amino Acid Sequence↗

PubMed1989

Sensitization of Edman amino acid derivatives using the fluorescent reagent, 4-aminofluorescein.

The ability to analyze amino acid derivatives at the femtomole level is one of the most interesting challenges in the field of protein microsequencing. 2-Anilino-5-thiazolinone amino acids, obtained by Edman degradation, were quantitatively derivatized with fluorescent primary amines. The most fluorescent reagent tested was 4-aminofluorescein. The amino acid derivatives sensitized with this reagent were separated using reversed-phase high-performance liquid chromatography and identified at the 100 attomole level. Incorporation of this method into the operation of a conventional automated sequencer is also described.

Amino Acid Sequence↗

PubMedDate not supplied

Computed tomography of neck lymph nodes involved with malignant lymphoma: comparison with ultrasound.

CT images of 24 patients with head and neck lymphoma were retrospectively reviewed, compared with ultrasonograms, and compared with CT images of 13 patients with lymph node metastases. In nine (38%) of 24 patients, some lymph nodes with lymphomatous involvement showed a spotty or linear pattern of contrast enhancement. In two of these nine patients, a dendritic pattern of contrast enhancement between multiple enlarged lymph nodes was observed. The same pattern appeared as spotty, linear, or dendritic hyperechoic areas on the ultrasonogram. None of 13 patients with lymph node metastases showed a spotty, linear, or dendritic pattern of contrast enhancement. Ten of 13 (77%) showed ring-like contrast enhancement on CE-CT images. The spotty or linear contrast enhancement in enlarged lymph nodes and the dendritic contrast enhancement in confluent lymph nodes could be useful CT findings in diagnosing nodal involvement with malignant lymphoma.

Adult↗