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Biomedical subjects

H Iida

Publications and source records attributed to H Iida.

At least 505 records · Page 28Linked to original sources
PubMed1986

Rhizoxin, a macrocyclic lactone antibiotic, as a new antitumor agent against human and murine tumor cells and their vincristine-resistant sublines.

Rhizoxin, isolated from a plant pathogenic fungus which causes rice seedling blight, inhibits the mitosis of the tumor cells in a manner similar to that of Vinca alkaloids as revealed by morphological study and flow cytometry analysis. This new 16-membered macrocyclic lactone showed similar chemotherapeutic effects to those of vincristine against L1210 and P388 leukemia-bearing mice. The drug is also effective against B16 melanoma inoculated i.p. or s.c. Rhizoxin, in contrast to the ansamacrolide, maytansine, was effective against human and murine tumor cells resistant to vincristine and Adriamycin in vitro and in vivo. A maximum 60% increase in life span was obtained in mice inoculated with P388 leukemia resistant to vincristine. Rhizoxin showed greater cytotoxicity in cultured tumor cells than did vincristine. Rhizoxin seems to bear consideration for further development as a new chemotherapeutic agent.

Animals↗
PubMed1985

Potentiation of antitumor agents by calcium channel blockers with special reference to cross-resistance patterns.

The calcium channel blockers verapamil, diltiazem, nicardipine, and niludipine potentiated the antitumor activities of mitotic poison antitumor agents, such as vincristine, vinblastine, vindesine, VP16-213, and taxol in P388 leukemia cells resistant to vincristine. The potentiating effect was generally dependent on the extent of cross-resistance seen in the cell line for these drugs. Calcium channel blockers also potentiate the antitumor activities of several DNA-interacting drugs, such as adriamycin, THP-adriamycin, daunomycin, aclacinomycin A, mitomycin C, actinomycin D, mitoxantrone, and nogalamycin derivatives in P388 leukemia resistant to adriamycin. Greater potentiation was observed for those antitumor agents to which the ADM-resistant cell line had become markedly cross-resistant, with the exception of the nogalamycin derivatives. Only a two-fold enhancement was observed for mitomycin C and aclacinomycin, as the cell line was only weakly cross-resistant to these agents. These results suggest the potential for therapeutic gain through the use of calcium channel blockers in combination with classic chemotherapeutic agents.

Animals↗
PubMed1985

Inhibition of spontaneous and experimental tumor metastasis by the calcium antagonist verapamil.

Verapamil, a calcium antagonist, inhibited both experimental (IV inoculation of tumor cells) and spontaneous metastasis (SC inoculation) of the highly metastatic B16 melanoma and colon adenocarcinoma 26 cell lines. Verapamil treatment resulted in a maximum 80% inhibition of metastases, the degree of inhibition varying among the different metastatic systems. Verapamil inhibited platelet aggregation induced by these tumor cell lines, the patterns of inhibition being different for B16 melanoma and colon adenocarcinoma. The inhibition of platelet aggregation induced by tumor cells is proposed as a mechanism by which the calcium antagonist exerts its antimetastatic effect. These results, together with our previous findings that calcium antagonists can increase the cytotoxicity of drugs in tumor cells with induced or inherent drug resistance by inhibiting outward transport of the drug, indicate that calcium antagonists have potential as a new class of adjuvant agents in the field of cancer chemotherapy.

Animals↗
PubMed1985

The structural relation between the antigenic determinants to monoclonal antibodies and binding sites to rat brain synaptosomes and GT1b ganglioside in Clostridium botulinum type C neurotoxin.

The inhibition of the binding of 125I-labeled Clostridium botulinum type C neurotoxin to synaptosomes by unlabeled toxin indicated that there were two kinds of receptors on the synaptosomal membrane. The dissociation constants (Kd) were calculated as 79 pM and 35 nM from the concentration of unlabeled toxin that induced half-displacement of bound 125I-toxin. These values agree satisfactorily with the values obtained from direct binding experiments (Agui, T, Syuto, B., Oguma, K., Iida, H., & Kubo, S. (1983) J. Biochem. 94, 521-527). The inhibition of the binding of 125I-toxin to synaptosomes and N-acetylneuraminyl(alpha 2-3)galactosyl(beta 1-3)N-acetylgalactosaminyl(beta 1-4) [N-acetylneuraminyl(alpha 2-8) N-acetylneuraminyl(alpha 2-3)]galactosyl(beta 1-4)glucosyl(beta 1-1)ceramide (GT1b) by unlabeled heavy chain indicated that heavy chain facilitates the binding of toxin to synaptosomes and GT1b. The synaptosomal and heavy chain complex Kd values were estimated as 12 nM and 24 microM. Monoclonal antibodies C-9 and CA-12 recognized the binding sites to GT1b and synaptosomes, respectively. Antigenic determinants against the two antibodies are presumably partially overlapping, and the overlapping area seems to be essential to the reaction between toxin and C-9 antibody.

Animals↗
PubMed1985

Glomerular deposition of IgA in experimental hepatic cirrhosis.

Wistar rats rendered cirrhotic with carbon tetrachloride excreted significant proteinuria and hematuria. Serum levels of IgA and IgG were significantly elevated in cirrhotic animals. They showed mild mesangial proliferation and immunofluorescent studies revealed deposits of IgA and IgG predominantly in mesangial areas and along capillary walls. These findings were very similar to those seen in patients with hepatic cirrhosis or IgA nephropathy. The deposits of IgA were also found in hepatic tissue from cirrhotic animals. The intensity and distribution of glomerular IgA deposits were not diminished after treatment with acid buffer. These results suggest that glomerular IgA are IgA polymers and decreased hepatic clearance of hepatic IgA polymers may be responsible for the glomerular deposition of IgA.

Animals↗
PubMed1985

Benign hemangioendothelioma of the pancreas with obstructive jaundice.

A 3-year-old boy with benign hemangioendothelioma of the pancreas is reported. He showed the presenting sign of obstructive jaundice. The boy was treated with temporary choledochojejunal bypass without additional treatment. In a 16-month follow-up the child has been well and asymptomatic. Laboratory data showed no abnormality. Biopsied specimen of pancreatic head showed hemangiomatous pattern histologically. Immunohistochemical studies of the biopsy revealed positive reaction to factor VIII-related antigen (FVIII-RAG), and endothelial cell marker, supporting an endothelial origin. Hemangioendothelioma has a favorable prognosis and spontaneous regression can be expected. So the first treatment of the tumor should be conservative.

Child, Preschool↗
PubMed1985

Membranous glomerulonephritis associated with enterococcal endocarditis.

An autopsy case of membranous glomerulonephritis associated with enterococcal endocarditis was reported. Although enterococcal antigen was not identified in glomerular deposits, the eluate from the patient's renal tissue was shown to specifically recombine with cells of the enterococcus isolated from his own ante mortem blood. Hypocomplementemia, circulating immune complexes and antienterococcal antibodies were also observed. These findings suggest that enterococcus-related immune complexes played a role in the pathogenesis of glomerulonephritis associated with enterococcal endocarditis in this patient.

Aged↗
PubMed1985

Acute interstitial nephritis with bone marrow granulomas and uveitis.

A case of interstitial nephritis with bone marrow granulomas and uveitis was presented. A 53-year-old woman was found to be uremic in the course of rheumatoid arthritis. The renal biopsy revealed acute interstitial nephritis with eosinophilic infiltration. She also had bone marrow granulomas and uveitis. These findings were compatible with those of the syndrome described by Dobrin et al. The etiology and the pathogenesis of this syndrome remain unknown. However, the elevation of the erythrocyte sedimentation rate, raised levels of serum immunoglobulins, presence of circulating immune complexes and decreased T-cell population observed in this patient suggest the involvement of immunological disorders.

Acute Disease↗
PubMed1985

Clinical disorders observed in a beagle breeding colony.

Disorders in a beagle breeding colony were discussed, based on 472 clinical charts made in 1974-1983. In 201 neonates less than a week old, hypothermia associated with pneumonia was mostly seen. In 31 puppies from one week to two months old and in 46 young dogs from two months to a year old, pneumonia, canine parvovirus infection, dermal abscess and dermatosis were mostly found. In 91 dogs aged from one to five, trauma, intervertebral disc protrusion, dermal abscess, dystocia, claudication and otohematoma were frequently noted. In 103 animals over five years old, intervertebral disc protrusion, tumors, abscess, trauma and otohematoma were observed most often.

Age Factors↗