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Biomedical subjects

C Yoshida

Publications and source records attributed to C Yoshida.

At least 55 records · Page 3Linked to original sources
PubMed1990

Neutralization of hemorrhagic snake venoms by sera of Trimeresurus flavoviridis (Habu), Herpestes edwardsii (mongoose) and Dinodon semicarinatus (Akamata).

The sera of T. flavoviridis (Habu), H. edwardsii (mongoose) and D. semicarinatus (Akamata, non-venomous snake) were tested for their capacity to neutralize 28 species of hemorrhagic snake venoms in vitro. The sera of these animals neutralized a variety of hemorrhagic venoms, suggesting a common structure for a hemorrhagic factor and a similar mechanism of neutralization for the antihemorrhagic factor in the sera. The serum of T. flavoviridis neutralized the lethal toxicity of the T. flavoviridis venom but could not neutralize those of the other hemorrhagic venoms at all. The sera of H. edwardsii and D. semicarinatus did not inhibit the activity of all hemorrhagic venoms.

Animals↗
PubMed1990

Reversal of azidothymidine-induced bone marrow suppression by 2',3'-dideoxythymidine as studied by hemopoietic clonal culture.

The hematological toxicity of the antiviral drug azidothymidine (AZT) was studied in vitro by measuring the cell growth of hematopoietic progenitor cells obtained from normal bone marrow. AZT inhibited the growth of granulocyte-macrophage (CFU-GM) and early and late erythroid (BFU-E and CFU-E) progenitors in a dose-dependent manner. The hemopoietic inhibition of AZT was significantly reduced by the addition of 2',3'-dideoxythymidine (2',3'-ddT). The results suggest that 2',3'-ddT may be of potential value in reducing AZT toxicity.

Bone Marrow↗
PubMed1990

[A metastatic Merkel cell carcinoma successfully treated with chemotherapy].

A 68-year-old man referred to the hospital because of a swelling of his bilateral cervical, left supraclavicular, and left axillary lymph nodes, and an ulcerated tumor in the right palatine tonsil. Three years previously, he had undergone a local excision in the left forearm of a skin tumor that had been pathologically diagnosed as a Merkel cell tumor. CT scan demonstrated an abdominal mass and his serum neurospecific-enolase (NSE) was found to be 20.3 ng/ml. Following biopsies of the lymph nodes and the tumor in the right tonsil, a metastatic Merkel cell carcinoma was diagnosed. Systemic chemotherapy thus was begun with doses of cyclophosphamide, doxorubicin and vincristine. After three cycles were completed, tumor were no longer present and his NSE returned to normal. Three months after the discontinuance of chemotherapy, he remains disease-free.

Aged↗
PubMed1989

Prognostic implication of sequential bone marrow cultures in the myelodysplastic syndromes.

Twenty-five patients with newly-diagnosed myelodysplastic syndromes were studied by the clonal culture method at least three times during the clinical course. Clinical outcomes of the patients were classified into: a stable disease (ten patients); subsequent leukemic transformation (eight patients) and nonleukemic death (seven patients). The growth of the marrow granulocyte-macrophage progenitors (CFU-GM) at the time of diagnosis was significantly related to the survival. In addition, sequential changes in the CFU-GM growth patterns correlated with the different clinical outcome of myelodysplastic syndromes patients.

Aged↗
PubMed1988

Improvement of a procedure for preparing single smooth muscle cells from guinea pig tenia coli by purified collagenase and papain.

Procedures for isolating single smooth muscle cells from tenia coli of guinea pigs have been developed. The cells were isolated with a combination of highly purified collagenase and a small amount of strong peptidase, papain, in the presence of Ca. This combination resulted in approximately a 100-fold yield of the single cells as compared with the ordinary method in which only collagenase preparations contaminated with various peptidases were used. More than 95% of the single cells were viable when examined by the trypan blue exclusion technique. In addition, this combination greatly increased the responsiveness to agonists such as carbachol (CCh). A concentration of CCh for the half maximum response for this preparation was about one five-hundredth that of cells prepared by the ordinary method. This value was approximately one-quarter that of intact tissue. This preparation can be used to investigate the physiology, pharmacology, and biochemistry of smooth muscle.

Animals↗
PubMed1987

Preparation of single smooth muscle cells from guinea pig taenia coli by combinations of purified collagenase and papain.

Procedures for isolation of single smooth muscle cells from taenia coli of guinea pigs have been developed. The preparation was performed with a combination of highly purified collagenase prepared by Amano Pharmaceutical Co. (Japan) and papain obtained from Sigma Chemical Co. (Type III). This combination resulted in very high yield of the single cells (39.2 +/- 4.5 X 10(3) cells/mg tissue wet wt) and less cell debris. In the ordinary procedure, commercially available collagenase preparations contaminated with various peptidases have been used. With these enzyme preparations, however, the yield of single cells was dependent on the batch of the preparations, and a large amount of cell debris was contaminated. Combination of the highly purified collagenase and papain resulted in higher yields constantly. Cells, isolated with these enzymes in a medium consisting of 140 mM KCl, 1.0 mM MgCl2, 4.2 mM Hepes, and 5.6 mM glucose (pH 7.4), were spindle shaped. The length of the cells was 185.9 +/- 5.2 micron (n = 90) and the diameter was approximately 12.6 micron. The diameter was not dependent on the cell length. More than 80% of the single cells were viable when examined by trypan blue exclusion technique. Under the depolarized condition, cells remained viable longer because of lower energy consumption, and these cells were contracted by Ca dose dependently. The dose-response relationship was similar to that obtained with intact tissue. Because the cells are constantly available with higher yield, the preparation might be applicable for biochemical research such as ion flux. Details of cell properties under the physiological conditions are under investigation.

Animals↗
PubMed1987

Ultrastructure of single smooth muscle cells contracted by carbachol and calcium ion.

The ultrastructural changes of single smooth muscle cells of guinea pig taenia coli during contraction evoked by Ca2+ (Ca) and carbachol (CCh) were investigated by transmission and scanning electron microscopy. Cells, prepared in the presence of a high concentration (140 mM) of KCl, without addition of Ca, exhibited smooth surfaced contour. The contraction of these cells were dose dependent upon Ca. With the increase in Ca concentration, the contraction was accompanied with formation of processes (0.15 micron thick and 1 micron long), membrane evaginations of various sizes and shapes and cores densely packed with filaments at the bottoms of all evaginations. Cells, prepared in the presence of 0.18 mM Ca and at a physiological concentration (2.7 mM) of KCl, had two populations: One had shallow invaginations of the cell membrane and the other had spinous processes. Cells of both types were responsive to CCh and the spinous processes disappeared during contraction but evagination did not appear. Differences in ultrastructural changes during contractions between single smooth muscle cells and intact tissues may be due to the fact that single cells are mechanically free from adjacent cells and connective tissues. It is also possible that membrane properties change during isolation, particularly when cells are isolated in Ca free medium.

Animals↗
PubMed1987

Studies on isolated smooth muscle cells. IX. Application of papain for isolation of single smooth muscle cells from guinea-pig taenia coli.

To prepare single smooth muscle cells from the taenia coli of guinea pig, the application of papain to the enzymatic solution was examined under two conditions: 1) the isolation in a modified Tyrode solution (containing 0.18 mM Ca2+: 0.18 mM Ca2+-Tyrode solution) and 2) the isolation in a high-K+ Tyrode solution (Na+ was replaced by K+, and Ca2+ was not added: high-K+ Tyrode solution). The presence of papain during collagenase digestion reduced contamination of broken cells and cell debris. In the case of the high-K+ Tyrode solution, papain increased the yield of single cells significantly. The cells were contracted in a dose-dependent manner by Ca2+ in the high-K+ Tyrode solution and by carbachol in 0.18 mM Ca2+-Tyrode solution; furthermore, the contractions were antagonized by verapamil and atropine, respectively. Treatment with papain did not affect cell sensitivity to the stimulants. Therefore, our results suggest that the addition of papain is useful for the isolation of single cells to investigate the physiological and pharmacological characteristics of smooth muscle.

Animals↗
PubMed1986

Studies on monocyclic beta-lactam antibiotics. IV. Synthesis and antibacterial activity of (3S,4R)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-(O-substituted oxyimino)acetamido]-4-methyl-1- (1H-tetrazol-5-yl)-2-azetidinones.

The synthesis and in vitro activity of the 3-(O-substituted oxyiminoacetamido)-2-azetidinones (IV) possessing a tetrazole moiety at N-1 position are described. The introduction of lipophilic functions into the oxyimino moiety gave in some good activity against staphylococci, but decreased activity against Gram-negative bacteria. In contrast, the introduction of hydrophilic functions such as carboxycyclobutane resulted in strong activity against Gram-negative bacteria including Pseudomonas aeruginosa, and no or very small activity against the staphylococci.

Anti-Bacterial Agents↗
PubMed1986

Studies on monocyclic beta-lactam antibiotics. V. Synthesis and antibacterial activity of 3-[2-(2-aminothiazol-4-yl)-(Z)-2-(O-substituted oxyimino)-acetamido]-1-(1H-tetrazol-5-yl)-2-azetidinones having various functional groups at C-4 position of beta-lactam.

The synthesis and antibacterial activity of the 3-[2-(2-aminothiazol-4-yl)-(Z)-2-(O-substituted oxyimino)acetamido]-1-(1H-tetrazol-5-yl)-2-azetidinones++ + having various functional groups at C-4 position of beta-lactam are described. These compounds exhibited a strong activity against a variety of Gram-negative bacteria including beta-lactamase-producing strains. Among various C-4 substituents explored, the fluoromethyl and carbamoyloxymethyl moiety were found to increase the activity.

Anti-Bacterial Agents↗
PubMed1985

[Pharmacological studies on schizandra fruits. III. Effects of wuweizisu C, a lignan component of schizandra fruits, on experimental liver injuries in rats].

The effects of wuweizisu C, a lignan component of schizandra fruits, on liver injuries induced by carbon tetrachloride (CCl4), d-galactosamine and dl-ethionine were investigated by means of serum-biochemical and histopathological examinations in rats. Pretreatment or combined administration of wuweizisu C dose-dependently reduced the elevation of serum transaminase activity and histological changes such as fatty degeneration, cell necrosis, inflammatory cell infiltration, etc., which were caused by the single administration of 1 ml/kg, p.o., or the repeated administration of 0.2 ml/kg, s.c., daily for 4 days of CCl4, respectively. The effects of wuweizisu C on the liver injuries induced by a low dose (200 mg/kg, i.p.) and a high dose (400 mg/kg, i.p.) of d-galactosamine were compared with those of uridine. Wuweizisu C significantly lowered the rise of serum transaminase activity after the administration of a low dose of d-galactosamine in the serum-biochemical analysis. A tendency was also shown to inhibit cell necrosis and inflammatory cell infiltration caused by both doses of d-galactosamine in the histopathological examination. On the other hand, uridine markedly repaired the serum-biochemical and histopathological changes after the administrations of both doses of d-galactosamine. Also wuweizisu C cured the liver injury by the repeated administration of 150 mg/kg, i.p., daily for 4 days of d-galactosamine. After the repeated administration of 250 mg/kg, s.c., daily for 4 days of ethionine, liver cell atrophy, diffuse fatty degeneration and decrease of serum triglyceride were observed, but not cell necrosis. Wuweizisu C dose-dependently inhibited fatty degeneration and decrease of serum triglyceride. These findings suggest that wuweizisu C can be protective and/or therapeutic on hepatocellular phenomena such as cell necrosis, fatty degeneration, inflammatory cell infiltration, etc., in human hepatitis.

Animals↗
PubMed1985

Studies on monocyclic beta-lactam antibiotics. II. Synthesis and antibacterial activity of 3-acylamino-2-azetidinone-1-oxysulfonic acids.

The synthesis and in vitro antibacterial and beta-lactamase inhibitory activity of the 2-azetidinone-1-oxysulfonic acids having a substituent at C-4 position of the beta-lactam ring are described. The influence of C-4 substituents on the antibacterial activity was examined for the compounds having alpha-ureidoacetyl or alpha-oxyiminoacetyl group as acyl side chain at C-3 position. The antibacterial activity is correlated with the C-4 substituents and acyl side chain. Especially, 4(R)-methyl substituted derivatives exhibited excellent activity against Gram-negative bacteria and 4-dimethyl substituted derivatives exhibited strong activity against resistant Gram-negative bacteria except for Pseudomonas aeruginosa. 39 and 40 showed strong inhibitory activity against cephalosporinase of Enterobacter cloacae H-27.

Anti-Bacterial Agents↗
PubMed1984

Toxicological studies on a new macrolide antibiotic, midecamycin acetate (miocamycin). Part VI-1. Acute toxicity in infant mice in comparison with young adult mice.

Sutherland and Weiss et al. reported cases of newborn human deaths or Gray syndrome after overdosage of chloramphenicol. In general, it has been reported that the acute toxicities of drugs are enhanced in immature animals compared with adult animals. The objective of this study was to determine the LD50 values in infant (5-day-old) and young adult (5-week-old) male and female mice after single subcutaneous and oral administration of MOM, non-crystalline solid and to estimate the toxicity ratio of those LD50 values. LD50 values of MOM, non-crystalline solid, were more than 5,000 mg/kg and the lethal toxicity was the same in infant and adult mice. Toxicity ratios were not obtained.

Age Factors↗