Search PubMed⌕ Search

Biomedical subjects

M Katoh

Publications and source records attributed to M Katoh.

At least 343 records · Page 19Linked to original sources
PubMed1985

Monoclonal antibodies against rabbit mammary prolactin receptors. Specific antibodies to the hormone binding domain.

Three monoclonal antibodies (M110, A82, and A917) were obtained by fusing myeloma cells and spleen cells from mice immunized with partially purified rabbit mammary gland prolactin (PRL) receptors. All 3 antibodies were capable of complete inhibition of 125I-ovine prolactin (oPRL) binding to rabbit mammary PRL receptors in either particulate or soluble form. M110 showed slightly greater potency than oPRL in competing for 125I-oPRL binding. These antibodies also inhibited PRL binding to microsomal fractions from rabbit liver, kidney, adrenal, ovary, and pig mammary gland, although A82 showed poor inhibition in pig mammary gland. There was no cross-reaction of any of the 3 monoclonal antibodies (mAbs) for the other species tested: human (T-47D breast cancer cells) and rat (liver, ovary). In order to confirm that these antibodies are specific to the binding domain, antibodies were purified, iodinated, and binding characteristics were investigated. 125I-M110 and 125I-A82 binding was completely inhibited by lactogenic hormones, whereas nonlactogenic hormones did not cross-react. Competition of 125I-M110 by oPRL (ID50 = 0.44 nM) was comparable to that of 125I-oPRL by unlabeled oPRL (ID50 = 0.35 nM), while 125I-A917 binding was only partially competed (30-60%) by lactogenic hormones. Tissue and species specificity of labeled antibody binding paralleled results of binding inhibition experiments using 125I-oPRL. In addition, A82 and A917 completely inhibited 125I-M110 binding. In contrast, 125I-A82 binding was stimulated by A917 and 125I-A917 binding was stimulated by A82. These findings indicate that monoclonal antibodies can be readily prepared from partially purified PRL receptors from rabbit mammary gland; two antibodies (M110 and A82) are hormone binding site specific while the other (A917) binds a domain partially but not entirely distinct from the hormone binding site, and that all three antibodies have strong species specificity.

Animals↗
PubMed1985

Biological activities of binding site specific monoclonal antibodies to prolactin receptors of rabbit mammary gland.

The biological activity of three monoclonal antibodies (mAbs) against the rabbit mammary prolactin (PRL) receptor (M110, A82, and A917) were investigated using explants of rabbit mammary gland. The three mAbs which were all able to inhibit the binding of 125I-ovine prolactin to its receptor had different biological activities. Two mAbs (M110 and A82) were able to prevent the stimulating effect of PRL on casein synthesis when the molar ratio between the mAb and PRL was 100. At a lower concentration, M110 moved the PRL dose-response curve to the right by a factor of 2.4. This mAb was also effective in vivo, reducing milk production in a lactating rabbit, in a similar fashion to the prolactin lowering drug, CB-154. One mAb (A917) was able to mimic the action of PRL on both casein and DNA ([3H]thymidine incorporation) synthesis, whereas the other two mAbs were without any stimulatory effect. For this stimulatory effect to be observed, bivalency of the antibody was essential, since monovalent fragments, which were able to inhibit PRL binding, had no agonistic activity. The ability of the mAbs to induce a down-regulation of receptors was also studied. M110, which was equipotent to PRL in occupation of receptors, induced no down-regulation, while A917, which had full biological activity, induced only a small degree of down-regulation. These studies suggest that the binding domain of the receptor might be relatively complex, since only a part of this domain recognized by the antibody with PRL-like activity was able to induce hormonal action. Alternatively, only those antibodies able to microaggregate the receptors may possess PRL-like activity.

Animals↗
PubMed1985

Prolactin receptor: identification of the binding unit by affinity labelling and characterization of poly- and monoclonal antibodies.

The prolactin receptor localized in rabbit mammary gland membranes has been identified by affinity labelling using covalent cross-linking agents such as a unique protein chain of approximately 32,000 daltons. After partial purification (5,000-fold) of these receptors from mammary gland homogenate, polyclonal antibodies, which specifically and completely inhibit prolactin binding in all organs and in all species studied, were raised. These antibodies possessed prolactin-like biological activity (casein synthesis) on rabbit mammary gland explants. Monoclonal antibodies specifically directed against the binding domain of the receptor were also obtained. These antibodies were more species-specific than the polyclonal antibodies. The most potent (M110) possessed higher affinity than prolactin for the receptor and could be a very effective tool to elucidate the structure of the receptor and its immunological detection.

Animals↗
PubMed1985

Prolactin-binding components in rabbit mammary gland: characterization by partial purification and affinity labeling.

The molecular characteristics of the PRL receptor isolated from rabbit mammary gland microsomes were investigated. Two approaches were employed: 1) affinity purification of PRL receptors and direct electrophoretic analysis, and 2) affinity cross-linking of microsomal receptors with [125I]ovine PRL [( 125I]oPRL). PRL receptors were solubilized from mammary microsomes with 3-[( 3-cholamidopropyl)dimethylammonio]1-propane sulfonate and purified using an oPRL agarose affinity column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining of the gel revealed at least nine bands, including a 32,000 mol wt band which was most intensively labeled with 125I using the chloramine-T method. Covalent labeling of PRL receptors with [125I]oPRL was performed using N-hydroxysuccinimidyl-4-azido benzoate, disuccinimidyl suberate, or ethylene glycol bis (succinimidyl succinate). A single band of 59,000 mol wt was produced by all three cross-linkers when sodium dodecylsulfate-polyacrylamide gel electrophoresis was performed under reducing conditions. Assuming 1:1 binding of hormone and binding subunit and by subtracting the mol wt of [125I]oPRL, which was estimated from the migration distance on the gel, the mol wt of the binding subunit was calculated as 32,000. In the absence of dithiothreitol during electrophoresis, only one major hormone-receptor complex band was observed. The same mol wt binding components were also detected in microsomal fractions of rabbit kidney, ovary, and adrenal. A slightly higher mol wt binding subunit was observed in rat liver microsomes. Rabbit liver microsomes revealed five [125I]oPRL-binding components, three of which were considered to be those of a GH receptor. Moreover, affinity labeling of detergent-solubilized and affinity purified mammary PRL receptors showed a similar major binding subunit. From these observations, we conclude that this predominant 32,000 mol wt component is a major binding subunit of the PRL receptor molecule and does not aggregate with itself or with other subunits through S-S linkages.

Affinity Labels↗
PubMed1985

Mutagenicity testing of ST-film with the Ames test, chromosome test in vitro and micronucleus test in female mice.

The mutagenicity of ST-film and its components polyoxyethylenenonylether (NP-10) and polyvinylalcohol (PVAL) were studied by a reverse mutation test in S. typhimurium (Ames test), a chromosome test in cultured Chinese hamster V 79 cells and a micronucleus test in female mice. The results obtained from these test systems were all negative. Thus, it may be concluded that ST-film is not mutagenic either in vitro or in vivo mutagenicity testing systems.

Animals↗
PubMed1985

Protective effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on carbon tetrachloride-induced liver injury in mice and rats.

The protective effect of malotilate was studied on the liver injury induced by carbon tetrachloride (CCl4) in mice and rats. Plasma GOT and GPT activities were used as indices for the liver injury, and the liver was histopathologically examined. A remarkable suppressing effect on the liver injury was observed when malotilate was orally given 6 hr prior to oral administration of CCl4 in mice and 3, 6 or 12 hr in rats. Malotilate was also effective in preventing the liver injury caused by intraperitoneal injection of CCl4, indicating that the protective effect is not derived from the decreased CCl4 absorption. The liver injury was suppressed even when malotilate was given 12 or 24 hr prior to oral administration of CCl4 in mice and 24, 48 or 72 hr in rats. It may be the characteristic of malotilate that the protective effect lasts for a long period. It is supposed that the effect is due not only to the inhibition of the metabolic activation of CCl4 but also the other action(s) of malotilate.

Administration, Oral↗
PubMed1985

Antiarrhythmic effect of diltiazem during halothane anesthesia in dogs and in humans.

The antiarrhythmic effects of diltiazem (DL), a slow channel inhibitor, were evaluated in the presence of epinephrine-halothane-induced arrhythmias in dogs, of premature ventricular contractions (PVCs) during anesthesia in patients (n = 10), and of tachyarrhythmias with associated atrial fibrillation (AF) during anesthesia in patients (n = 9). The arrhythmogenic dose of epinephrine (ADE) during one MAC of halothane in dogs was increased from 1.13 +/- 0.21 to 3.14 +/- 0.89 microgram X kg-1 X min-1 by the administration of 0.3 mg/kg of DL. This suggests that DL significantly increases the threshold for the induction of arrhythmias associated with epinephrine and halothane. In 10 patients, PVCs that appeared spontaneously during halothane anesthesia were eliminated by the intravenous administration of DL (0.1 mg/kg). With an additional nine patients who had had AF preoperatively and suffered tachyarrhythmias during anesthesia, the intraoperative intravenous administration of DL significantly decreased heart rate (to less than 100 beats/min) within 10-15 min. Diltiazem is an effective means for the treatment of PVCs and AF-mediated tachyarrhythmias during anesthesia. Because of the pharmacologic properties of DL (e.g., depressing sinus and atrioventricular (AV) node function), DL should be used with caution in patients with a sick sinus syndrome or an AV block, or in the presence of beta-adrenergic antagonists.

Adolescent↗
PubMed1985

[Trigeminal neurinoma presenting abducens nerve palsy as initial symptom: a report of two cases].

Two cases of trigeminal neurinoma presenting abducens nerve palsy as initial symptom are reported. Case 1. A 33-year-old female was admitted because of double vision of two months duration. Neurological examination revealed left abducens nerve palsy. CT scan disclosed a left parasellar tumor with a homogeneous enhancement effect. The tumor was subtotally resected by left extradural subtemporal approach, and diagnosed as trigeminal neurinoma. Case 2. A 18-year-old female was admitted because of double vision of one month duration. Neurological examination revealed left mydriasis and left abducens nerve palsy. CT scan disclosed a low density mass in the left cerebellopontine angle region and enhanced parasellar mass. The cystic mass located at the posterior fossa was removed by left retromastoid suboccipital approach, and diagnosed as trigeminal neurinoma. In these two cases, the abducens nerve palsy disappeared within two months postoperatively. The trigeminal neurinoma presenting abducens nerve palsy as initial symptoms is rare. We were able to collect six similar cases from the literature. All of them, including present two cases, were classified as ganglion type. It was suspected that the abducens nerve was compressed by the trigeminal neurinoma at the cavernous sinus, the petrous apex or the posterior fossa.

Abducens Nerve↗