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Biomedical subjects

J Sakamoto

Publications and source records attributed to J Sakamoto.

At least 181 records · Page 10Linked to original sources
PubMed1985

Basal cell carcinoma with lung metastasis.

A forty-seven year-old man had a small ulceration on his left cheek. The ulcer had a repeated crust formation following removal, for ten years. The patient found a hard tumor in the deep site of the ulcer and the tumor was resected. The pathological diagnosis was basal cell carcinoma. The metastases to the regional lymph nodes developed one year later and these lymph nodes were resected. The histological picture was the same as seen in the primary tumor. Lung metastasis occurred three years later. The tumor was resected and the pathological diagnosis was basal cell carcinoma. Multiple lung metastases developed one year later and massive hemoptysis led to a sudden death two years after the thoracotomy. Thirty-seven cases of basal cell carcinoma with lung metastases were reported in the literature. This case is the thirty-eighth case and the third occurrence in a Japanese.

Basal Cell Carcinoma↗
PubMed1984

Analysis of the expression of H, Lewis, X, Y and precursor blood group determinants in saliva and red cells using a panel of mouse monoclonal antibodies.

Salivary glycoproteins from 33 normal individuals were analyzed with a panel of mouse monoclonal antibodies to H-1, H-2, Lea, Leb, X, Y and precursor blood group determinants. Samples from 19/33 individuals co-expressed Leb and Y-determinants (secretors) and 6/33 co-expressed Lea and X-determinants (non-secretors). Erythrocytes of these individuals were typed Le (a-b+) and Le (a + b-), respectively. In seven other salivas, only one specificity, either Lea, Leb, X or Y, was expressed and in one sample none of these determinants could be detected. Only one saliva sample expressed H-1 specificity and none expressed H-2 or type 1 precursor determinants. The absence of H-1 and H-2 structures in secretors and the resulting expression of difucosylated Leb and Y-structures is probably a tissue-specific trait of salivary gland secretions. The strict co-expression of Leb with Y and Lea with X supports the conclusion that only one 2-O-fucosyl-galactose transferase, which can fucosylate both type 1 and type 2 chains, exists in salivary glands. The finding that a number of individuals expressed neither X- nor Y-specificities was unexpected in view of previous work showing that the 3-O-fucosyl N-acetylglucosamine transferase involved in forming this structure is a ubiquitous enzyme. The individualistic expression of blood group phenotypes in tissues should be considered when the altered expression of blood groups in malignancy and other diseases is studied.

ABO Blood-Group System↗
PubMed1984

Identification of the nucleotide-binding site for ATP synthesis and hydrolysis in mitochondrial soluble F1-ATPase.

The binding of ADP to mitochondrial soluble F1-ATPase was studied by a membrane filtration method. One mol of F1, which contained about 1 mol of tightly bound adenine nucleotide, bound 4 mol of [alpha-32P]ADP at a saturating concentration of [alpha-32P]ADP. Two mol of the bound [alpha-32P]ADP was readily exchanged with medium nonradioactive ADP while the remaining 2 mol of the bound [alpha-32P] ADP was hardly exchanged (tightly bound [alpha-32P]ADP). F1 catalyzed the synthesis of [alpha-32P]ATP from the medium [alpha-32P]ADP and Pi. However, when exchangeably bound [alpha-32P]ADP was replaced by nonradioactive ADP, no [alpha-32P] ATP formation was observed. Furthermore, tightly bound [alpha-32P]ADP was not released from F1 during ATP hydrolysis catalyzed by the enzyme. These results indicate that both ATP synthesis and hydrolysis catalyzed by F1 occur at the exchangeable binding site and not at the tight binding site on the enzyme.

Adenosine Diphosphate↗
PubMed1984

Effect of dimethylsulfoxide on ATP synthesis by mitochondrial soluble F1-ATPase.

F1-ATPase isolated from bovine heart mitochondria catalyzes the synthesis of enzyme-bound ATP from externally added ADP and Pi in the presence of dimethylsulfoxide (DMSO) (Sakamoto, J. & Tonomura, Y. (1983) J. Biochem. 93, 1601-1614). When the concentration of DMSO in the reaction medium was decreased from 40% to 10% (w/v), the maximal amount of ATP formed decreased from 0.50 to 0.14 mol/mol F1 and the Pi concentration required for the half-maximal amount of ATP formed increased from 0.7 to 11 mM. On the other hand, the ADP concentration required for the half-maximal value and the rate of ATP formation were unaffected by the decrease in the DMSO concentration. These results suggest that DMSO increases the affinity of F1 and Pi and shifts the equilibrium from the enzyme-ADP-Pi complex to the enzyme-ATP complex during the ATP synthesis.

Adenosine Triphosphate↗
PubMed1982

Anemia and porphyria caused by N,N'-methylene-bis-acrylamide (MBA) in mice and rats.

The effects of N,N'-methylene-bis-acrylamide (MBA), a cross-linking agent, on blood and bone marrow after repeated oral doses, were studied in mice and rats. Body weight, three major elements of the blood - erythrocytes, leucocytes and platelets -, reticulocytes and bone marrow cells, were all reduced in either or both animals, especially in mice. Phenobarbital (PB) treatment did not greatly modify the effects of MBA in mice. An increase in free erythrocyte porphyrins and a decrease in ALA-D activity were observed in both animals. Urinary porphyrins were elevated in rats after MBA-dosing. PB-treatment did not significantly affect the elevation of porphyrins. After cessation of the MBA-dosing, all these changes were inclined to be restored to normal levels. Amounts of liver total porphyrins and microsomal P-450, and red cell fragility were within normal ranges in mice.

Acrylamides↗
PubMed1981

Neurotoxicity of acrylamide and related compounds and their effects on male gonads in mice.

Neurotoxicity of acrylamide and related compounds and their effects on the testis after repeated oral doses were studied in mice. Of fourteen analogues tested, five produced neuropathy. In decreasing order of potency as assessed by the rotated performance test, these were as follows: acrylamide greater than N-isopropylacrylamide greater than N-methylacrylamide = methacrylamide greater than N-hydroxymethylacrylamide. The development of neurotoxicity was either greatly reduced or delayed by phenobarbital treatment. Acrylamide, N-hydroxymethylacrylamide, N-isopropylacrylamide, N-methylacrylamide and N,N'-methylene-bis-acrylamide produced testicular atrophy. Atrophy was either prevented by phenobarbital treatment, as in the cases of acrylamide and N-isopropylacrylamide, or reduced, as in the case of N-hydroxymethylacrylamide. Histological changes in the testis produced by the active compounds were degenerations of the epithelial cells of the seminiferous tubules, with the interstitial cells being normal.

Acrylamides↗
PubMed1981

Effect of alternating administration of PS-K and carbazilquinone in tumor-bearing mice.

In order to establish procedure for immunochemotherapy, the delayed hypersensitivity reaction (DHR) was investigated in tumor-bearing mice treated with an immunopotentiator, basidiomycetes polysaccharide (PS-K). DHR in the group given continuous administration of immunopotentiator was initially much stronger than that in the untreated group; however, the reactions were the same by the 4th week. The tumor-bearing group give intermittent administration of immunopotentiator retained strong DHR throughout the course, even though prolonged continuous administration failed to maintain such elevated immunoresponses. Alternating treatment with PS-K and carbazilquinone induced much higher DHR and much longer survival. The experimental results showed that continuous administration of an immunopotentiator led to decreasing immune responses in tumor-bearing mice. Intermittent administration of immunopotentiator was proved to be effective in restoring tumor suppression.

Adjuvants, Immunologic↗
PubMed1980

Esophageal cyst, a case report and a review of the literature.

The esophageal cyst is a rare disease only 20 cases of which have been reported in the literature in Japan. We recently treated such a patient and at thoracotomy, we found the cyst to be located the submucosal layer of the esophagus. The cyst could be easily extirpated and the patient made an uneventful recovery. Gross findings revealed thick, yellow and mucus-like contents inside the cyst. Microscopically, the cyst was lined with ciliated columnar epithelium and there was no evidence of cartilage. The 21st such occurrence in Japan is reported herein and a discussion is made of related literature.

Aged↗
PubMed1980

Order of release of ADP and Pi from phosphoenzyme with bound ADP of Ca2+-dependent ATPase from sarcoplasmic reticulum and of Na+, K+-dependent ATPase studied by ADP-inhibition patterns.

The inhibition of Ca2+-dependent ATPase from SR [EC 3.6.1.3] by ADP was of mixed type under both low Ca2+ and high Mg2+ concentration and high Ca2+ and low Mg2+ concentrations. On the other hand, the inhibition of Na+, K+-dependent ATPase [EC 3.6.1.3] by ADP was of competitive type in the presence of low and high K+ concentrations. These results suggest that ADP is released before Pi from the phosphoenzyme with bound ADP (EPADP) in the case of Ca2+-ATPase, but that Pi is released before ADP in the case of Na+, K+-ATPase.

Adenosine Diphosphate↗
PubMed1979

The effect of intravenous hyperalimentation on cell mediated immunity.

The effect of intravenous hyperalimentation (IVH) on cell mediated immunity was examined in 22 patients. Each patient received PHA and PPD skin tests before and after the performance of IVH. In this study both PHA and PPD skin reactivity showed significant increase after IVH, and serum albumin levels had positive correlation with the PPD skin reaction changes. Absence of the established delayed hypersensitivity in the surgical patient, especially those with malignant diseases, is probably secondary to generalized malnutrition, and established cell mediated immunity can be restored by proper nutritional repletion.

Adult↗
PubMedDate not supplied

Reduction of regional contractile function by preconditioning ischemia does not play a permissive role in the infarct size-limitation by the preconditioning.

Although previous studies have shown that preconditioning cannot be explained by concurrent myocardial stunning alone, it remains unclear whether reduction of contractile function by preconditioning ischemia is required for its cardioprotective effect. The present study examined whether preconditioning occurs in the absence of regional contractile dysfunction. In the first series of experiments, rabbits received two cycles of 2-min coronary occlusion separated by 5-min reperfusion, with or without dobutamine infusion (10 micrograms/kg/min, i.v.) commencing before the onset of ischemia. Regional thickening fraction measured by epicardial Doppler sensor was 72.8 +/- 4.7% of baseline (mean +/- SEM) in the untreated group and 102.9 +/- 3.1% in the dobutamine group at the end of the second cycle of ischemia/reperfusion. In the second series of the study, four groups of rabbits underwent 30-min coronary occlusion and reperfusion. The control group was untreated, and the PC group was preconditioned with two cycles of 2-min ischemia/5-min reperfusion before the 30-min ischemia. The PC-DOB group received both preconditioning and dobutamine infusion (10 micrograms/kg/min, i.v.), which was started 5 min before the preconditioning and continued for 19 min. The DOB group was given dobutamine infusion like the PC-DOB group, but was not preconditioned. After 72-h reperfusion, infarct size and area at risk were determined by histology and fluorescent particles, respectively. Infarct sizes in the PC and PC-DOB groups (25.0 +/- 3.4% and 22.7 +/- 3.3% of area at risk, respectively) were significantly smaller than that in the control group (48.2 +/- 2.6%). In the DOB groups, infarct size (43.5 +/- 4.0%) was similar to the control value. Infusion of dobutamine at a dose sufficient to abolish the contractile dysfunction which would have been induced by ischemic preconditioning did not attenuate the infarct size-limiting effect of preconditioning. Thus, it is unlikely that reduction of contractile function plays a permissive role in the appearance of the cardioprotective effect of preconditioning.

Animals↗
PubMedDate not supplied

Suppression of reperfusion arrhythmia by ischemic preconditioning in the rat: is it mediated by the adenosine receptor, prostaglandin, or bradykinin receptor?

The mechanism for the suppression of reperfusion arrhythmia by preconditioning (PC) remains unknown. This study aimed to examine the roles of the adenosine receptor, prostaglandin (PG), and bradykinin (BK) receptor in PC. Under pentobarbital anesthesia, the coronary artery of the rat was occluded for 5 min and then reperfused. In untreated controls, this protocol induced ventricular tachycardia (VT) in 100% of the rats and ventricular fibrillation (VF) in 60%. PC with 2 min ischemia/5 min reperfusion prior to the 5 min coronary occlusion significantly reduced the incidence of reperfusion VT and VF to 30% and 0%, respectively. This antiarrhythmic effect of the PC was not blocked when rats were pretreated with 8-phenyltheophylline (8-PT, 10 mg/kg), aspirin-DL-lysin (18 mg/kg), or a specific BK receptor antagonist, Hoe140 (20 nmol/kg). None of these agents alone significantly modified the incidence of reperfusion VT or VF. These results suggest that neither the adenosine receptor, endogenous PG, nor BK receptor play a major role in the mechanism of suppression of perfusion arrhythmias by PC in the rat heart.

Adrenergic beta-Antagonists↗