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Biomedical subjects

S Sakuma

Publications and source records attributed to S Sakuma.

At least 271 records · Page 15Linked to original sources

Study on the function of the bent DNA within adenovirus type 2 EIA enhancer: analysis using an in vitro transcription system.

The role of the bent DNA within human adenovirus type 2 (Ad2) enhancer in transcriptional activation of E1A gene has been investigated. The bent region of the enhancer was substituted by a straight DNA fragment or by a bent DNA fragment of 194 bp from origin region of phage lambda replication. Employing an in vitro transcription system using HeLa cell extract, effects of mutant enhancers on E1A gene transcription were analyzed. The results obtained showed that the amount of transcripts is affected by changes in local conformation in and around the enhancer.

Adenovirus Early Proteins↗

Inhibition of paraquat accumulation in rabbit kidney cortex slices by ascorbic acid.

Effects of ascorbic acid and Fe2+ on the accumulation of paraquat into rabbit kidney cortical slices were studied. Ascorbic acid showed dose-dependent inhibition of paraquat accumulation. Fe2+ had a more powerful stimulatory effect on the lipid peroxidation of cortical slices than ascorbic acid, but it did not reduce paraquat accumulation. These results suggest that ascorbic acid is able to inhibit the accumulation of paraquat independent of its peroxidative action, and that ascorbic acid may serve as an antidote for the toxicity of paraquat.

Animals↗

[Radioimmunodetection of colorectal cancer, using anti-CEA monoclonal antibodies].

Aiming at radioimmunodetection of colorectal cancer, anti-CEA monoclonal antibodies (CEA102) were produced by immunization with purified CEA. CEA102 showed high specificity with colorectal cancer by mixed hemadsorption assay and immunoperoxidase technique. The antigen detected by CEA102 was confirmed to be carcinoembryonic antigen (CEA) and its molecular weight was estimated to be ca. 180,000 by biochemical analysis. The in vivo study using nude mice grafted a human colorectal cancer or a human malignant melanoma showed greater accumulation of 125I-labeled CEA102 in CEA-positive colorectal cancer than in nude mouse tissues and CEA-negative malignant melanoma. Moreover we successfully obtained scans with good localization of the grafted colorectal cancer on FCR (Fuji Computed Radiography). Using 131I-labeled CEA102 liver metastasis in the patient with colorectal cancer was successfully detected by external scanning with gamma-camera. These results suggest that radiolabeled CEA102 is useful for the detection of colorectal cancer.

Aged↗

[Radiological assessment of pulmonary function by computed radiography with imaging plates].

The usefulness of computed radiography with imaging plates (CR) for radiological assessment of pulmonary function was studied. Visibility of intrathoracic structures on CR images was compared with that on screen-film images. Intrathoracic structures included right intermediate arterial trunk, midzonal vessels, peripheral zonal vessels, the trachea at the level of the aortic arch, and lateral margin of the spine on posteroanterior radiographs. On lateral radiographs, the pulmonary apex, upper border of the aortic arch, anterior border of the heart, anterior margin of the ascending aorta, and trachea were included. Forty-six posteroanterior and 40 lateral radiographs taken by CR and screen-film radiography were reviewed. CR was often superior in identifying intrathoracic structures. Marked superiority of CR to screen-film radiography in visualizing intrathoracic structures was found in 48% of peripheral zonal vessels, 63% of tracheas on posteroanterior images, 46% of lateral margins of the spine, and 60% of pulmonary apexes. The superiority of CR is due to the wide dynamic range of imaging plates and image-processing procedures. CR will make it easier to identify multiple intrathoracic structures for radiographic measurements. In a second experiment chest radiographs were taken in both deep inspiration and expiration phase with one-shot dual-energy subtraction technique using the CR system in five patients with chronic pulmonary emphysema showing abnormal pulmonary function and 5 patients without any airway obstruction diseases. Original CR plain chest images and bone-subtracted chest images were displayed on a CRT (TDF-500AS, Toshiba Medical, Tokyo) and X-ray densitometry was attempted utilizing digital values.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

Evaluation of thyroid calcification using computed radiography with image plate.

The value of lateral magnification soft x-ray roentgenography using a Computed Radiography (CR) system was studied. ROC curve analysis revealed that a CR system has virtually the same, or a better ability than a screen-film system for detecting thyroid calcification. According to our criteria the CR system an accuracy rate of 77.1% in malignant/benign diagnosis was obtained.

Calcinosis↗

[Study on liver uptake changes in serial 67Ga scintigraphy].

During the past 3 years and 6 months, serial 67Ga-citrate scintigraphy have studied in 113 patients. 22 patients of these showed absent liver uptake. All cases had malignant tumors. 41% in malignant lymphoma and 20% in lung cancer showed absent liver uptake scintigraphy in their progress. This ratio is more frequent than reported ratio. There was significant relationship between therapy with antineoplastic agents and absent or increased liver uptake scintigraphy. 4 cases, treated by irradiation, showed absent liver uptake scintigraphy. In 3 cases, elevated liver uptake, one was administered renal toxic agent and all were given 5-FU. Mild change of accumulation in liver may be beyond reported ratio. 67Ga-citrate scintigraphy is repeatedly used in course of malignant patients. We must know given agents and past history of treatment when 67Ga scintigraphy is evaluated.

Adult↗

Quantification of leg muscle perfusion using thallium-201 single photon emission computed tomography.

The purpose of this study is to quantify leg muscle perfusion with 201Tl single photon emission computed tomography (SPECT). Six normal controls and 21 patients with peripheral arterial disease underwent this examination. Thallium-201 leg SPECT of both stress and redistribution was performed using a dual-headed digital gamma camera. Each slice of transverse images was normalized with pixels and whole-body counts. In normal controls, the activity of posterior tibial muscle components was significantly higher than that of anterior tibial muscle components (p less than 0.001). In 14 components, where patients had insignificant lesions, profile curves were normal in 10 (71%). In 62 components, where patients had arteriographically significant lesions, stress profile curves were abnormal in 57 (92%) compared with normal controls. Approximately, in half (28/62) components which had significant lesions, profile curves showed redistribution after 3 hr compared with normal redistribution curves. In three patients who underwent successful bypass graftings, the activity of each muscle component returned to a normal range.

Adult↗

[A very rare autopsy case of metastatic brain tumor originating from ureteral cancer].

We report here a very rare case of metastatic brain tumor originating from ureteral cancer which was verified at autopsy. An 88-year-old elderly woman was admitted to our department because of recurrent convulsions which started in March, 1987. Following this episode, right hemiparesis and speech disturbance appeared on June 6, 1987. Neurological examinations at admission on August 12, 1987 showed slightly disturbed consciousness, motor dominant aphasia, and dysphasia. Enhanced CT scan demonstrated a large tumor in the left frontal lobe with perifocal edema, and a small mass in the right frontal lobe (Fig. 1). Left carotid angiogram showed downward displacement of the middle cerebral artery complex at the Sylvian portion. After admission, she developed marked distention of the abdomen, with occurrence of hematuria followed by aggravation of respiration and consciousness. She died on September 2, 1987. Removal of metastatic brain tumor had not been performed due to the poor general condition of the patient. An autopsy was permitted. A coronal section of the cerebrum clearly demonstrated a large tumor in the left frontal lobe with small mass in the right frontal lobe (Fig. 2). Kidney and the ureter at the right side showed hydronephrosis and hydroureter because of the presence of ipsilateral ureteral tumor at the distal end (Fig. 3). Microscopical findings verified that the metastatic brain tumor was a transitional cell carcinoma, which was, histologically, completely the same as the ureteral tumor (Fig. 4, 5). No case of metastatic brain tumor originating from ureteral cancer has yet been reported, as far as the authors know.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Three Epstein-Barr virus (EBV)-determined nuclear antigens induced by the BamHI E region of EBV DNA.

In our previous study (Takada et al., 1986a), we showed that the BamHI E fragment of Epstein-Barr virus (EBV) DNA induces a nuclear antigen that is detected by human antisera against EBV-determined nuclear antigen (EBNA), when transfected into baby hamster kidney (BHK) cells. The present study shows that the sub-fragment containing the central open reading frame BERF2b of the BamHI E fragment (Baer et al., 1984) is responsible for nuclear antigen induction. In addition, 2 fragments corresponding to 2 other open reading frames of the BamHI E, BERFI and BERF4 also induce nuclear antigens upon transfection into BHK cells. These 3 antigens, designated RF2b, RFI and RF4 antigens, were serologically classified as EBNA and antigenically distinct. In immunoblotting analysis of latently EBV-infected BJ-B95-8 cells, 3 high-molecular-weight polypeptides (136, 142 and 147 kDa) were identified by anti-EBNA sera. Immunoblotting analysis of transfected BHK cells indicated that the RF2b antigen is 145 kDa in its native form and antigenically related to the 147-kDa protein of BJ-B95-8 cells. Although RFI and RF4 antigens were not detected by immunoblotting, reactivities of sera with RFI and RF4 antigens in the immunofluorescence test were correlated with those of sera with the 136- and 142-kDa polypeptides of BJ-B95-8 cells, respectively. The results suggest that 3 high-molecular-weight proteins of latently EBV-infected cells are encoded by 3 open reading frames of the BamHI E DNA fragment.

Animals↗

Type II collagen-induced murine arthritis. I. Induction and perpetuation of arthritis require synergy between humoral and cell-mediated immunity.

Immunization of DBA/1 mice with type II collagen resulted in typical and progressive arthritis, which is associated with the production of high titer of anti-collagen antibody and the induction of cell-mediated immunity as exemplified by delayed type hypersensitivity response as well as lymphokine production. In contrast, administration of heat-denatured collagen into DBA/1 mice failed to induce the arthritis. These mice produced only marginal antibody, whereas they developed comparable cell-mediated immunity to that induced by immunization with native collagen, and therefore the inoculation of heat-denatured collagen provided the regimen capable of inducing preferentially cell-mediated immunity without the generation of high level of antibody. Inasmuch as administration of antibody induced only marginal and transient joint swelling not associated with typical histologic lesion, the synergistic effect of humoral and cell-mediated immunities was investigated using antibody preparation and the regimen to induce selectively cell-mediated immunity. The results demonstrate that administration of antibody into DBA/1 mice pre-sensitized with heat-denatured collagen resulted in potent and progressive arthritis. Such synergy was further confirmed by the induction of arthritis in T cell-depleted DBA/1 mice that had been adoptively transferred with antibody and lymphoid cells from heat-denatured collagen-sensitized mice. Moreover, it was revealed that the nature of cells capable of transferring cell-mediated immunity was of Thy-1+ and L3T4+ Lyt-2-. These results indicate that anti-collagen antibody and L3T4+ T cell-mediated cellular immunity are crucially required for the perpetuated development of type II collagen-induced arthritis.

Animals↗

An acyclovir-resistant strain of herpes simplex virus type 2 which is highly virulent for mice.

Herpes simplex virus type 2 (HSV-2), strain YS-4 C-1, isolated by plaque cloning from a clinical isolate was found to be resistant to acyclovir (ACV; acycloguanosine) in vitro. It was sensitive to phosphonoacetic acid and 9-beta-D-arabinofuranosyladenine. Thymidine kinase (TK) activity of YS-4 C-1 was less than 1% of that of other strains from the same clinical source. However, thymidine plaque autoradiography showed that YS-4 C-1 was not completely deficient in TK activity. YS-4 C-1 showed high virulence for mice like other HSV-2 strains which were sensitive to ACV. YS-4 C-1 was able to establish latent infection in mice. Virus isolated from the brain of a mouse died after being inoculated with YS-4 C-1 was also resistant to ACV. ACV was not effective in mice inoculated with YS-4 C-1. This study shows that not all ACV-resistant strains are avirulent for mice.

Acyclovir↗

Herpes simplex virus type 1 infection in mice with severe combined immunodeficiency (SCID).

Herpes simplex virus type 1 (HSV-1) infection in mutant mice with severe combined immunodeficiency (SCID mice), i.e., mice in which the differentiation of both T and B lymphocytes is severely impaired, was studied. All control (infected and not treated with antibodies or with immune spleen cells) SCID mice were dead by 17 days after intracutaneous injection in the right midflank with 1 x 10(5) PFU of a virulent HSV-1 strain, Hayashida. Immunization with an avirulent strain of HSV-1 (SKa) did not protect them from death or prolong the survival time. Tissue virus titration of infected mice killed at various times after inoculation detected infectious virus in various organs, dorsal root ganglia, spinal cord, brain, kidney and adrenal gland in addition to the inoculation site of the skin in SCID mice, whereas virus could be detected only in the inoculation site and the nervous tissues in euthymic BALB/c mice, and in the adrenal gland from only one out of 17 nude mice. Human gamma globulin containing neutralizing antibody against HSV-1 prolonged the survival time but did not protect SCID mice from death. Transfer of spleen cells from immunized BALB/c mice protected the infected SCID mice from death. Treatment of spleen cells with anti-Thy 1.2 monoclonal antibody and complement abolished the protection.

Animals↗

Human papillomavirus DNA in condylomata acuminata from Japanese males.

We examined condylomata acuminata from Japanese males for the presence of human papillomavirus (HPV) genomes by Southern blot hybridization. HPV 6/11-related DNA was found in 91% (32/35) of the condylomata. HPV 6a DNA was found in 40% (14/35), HPV 6c DNA in 6% (2/35), and HPV 11a DNA in 37% (13/35). HPV 6-related DNA, which had an unusual PstI-cleavage pattern, was detected in one sample. Types and subtypes of HPV DNA in the samples studied (HPV 6a, 6c, and HPV 11a DNA) were not correlated with the patients' ages nor outcomes of the disease. HPV 16 DNA was not detected in any condyloma acuminatum.

Adult↗