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Biomedical subjects

K Sakamoto

Publications and source records attributed to K Sakamoto.

At least 829 records · Page 46Linked to original sources
PubMed1988

Bone marrow transplantation in miniature swine. III. Graft-versus-host disease and the effect of T cell depletion of marrow.

Graft-versus-host disease (GVHD) has been evaluated in partially inbred miniature swine in order to study this complication of allogeneic bone marrow transplantation (BMT) in a major histocompatibility complex (MHC) genetically defined large animal model. Bone marrow from MHC homozygous ("parental") swine was injected into irradiated (900 rads total-body irradiation) MHC heterozygous ("F1") swine that shared one haplotype with the donor. All 18 animals successfully engrafted with donor bone marrow, and 17 of these developed skin rash of varying intensity depending on the extent of T cell depletion of infused marrow. Of 18 animals, 8 received undepleted bone marrow from exsanguinated donors and 2 also received additional peripheral blood lymphocytes (PBL) as a source of mature T cells. All 8 showed a moderate-to-severe rash, and the 2 pigs that received additional donor PBL developed the most severe rash. The cutaneous eruption seen in this model clinically, histologically, and immunologically resembled human GVHD. Two protocols of T cell depletion of donor bone marrow by antiporcine T cell monoclonal antibodies plus complement were tested for their effect on development of GVHD. The combination of two monoclonal antibodies, 74-12-4 (PT4) and 76-2-11 (PT8), had a marginal effect on the subsequent development of cutaneous manifestations of GVHD. However, treatment of the donor marrow by a combination of three monoclonal antibodies--PT4, PT8, and MSA4 (PT11)--effectively decreased the severity of the GVHD skin rash. These results indicate that (1) the GVHD associated with allogeneic bone marrow transplantation in swine is dependent on T cells in the marrow; (2) effective T cell depletion of donor marrow by monoclonal antibodies and complement does not prevent engraftment; and (3) this swine GVHD model, which allows study with F1 and homozygous parental combinations in an MHC genetically defined large animal, is particularly useful for the understanding of GVHD pathogenesis, prevention, and treatment.

Animals↗
PubMed1988

[Long-term maintenance of human gall-bladder epithelia as xenografts following explant organ culture].

The purpose of present study is to establish a method that should enable us to keep a human gall-bladder epithelial tissue alive for a period long enough to observe morphological change after an exposure to a certain carcinogenic agents. Human gall-bladder epithelia obtained from surgically resected specimen were kept as an explant organ culture in vitro for the first 2 weeks. They were, then, xenotransplanted to the subcutaneous (S.C.) space of the athymic nude mice. The gall-bladder tissues obtained from 7 cases of cholecystolithiasis and 1 case of cholecysto-choledocholithiasis were used as materials in the present study. And the longest survivor among them in the nude mice was extensively studied in the present paper. After an interval of 4 to 27 weeks, the xenografts were recovered from the recipient mice and studied by light microscopy and histochemistry. The morphological changes of the explant epithelia during the organ culture were also studied. Parts of the explants were implanted in 6 nude mice. Each of the mice received 3 pieces of explants on the s.c. space in both of their flanks. All xenografts showed subcutaneous cyst formation. The cyst obtained 4 weeks after the implantation was consisted of a monolayer of cuboidal epithelial cells and those recovered from the recipient mice 24 and 27 weeks after the implantation were consisted of well growing columnar and cuboidal epithelial cells. In addition, sinus-like structures were observed beneath the cystic epithelia. The viability of the cells was excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Verapamil enhancement of antitumor effect of cis-diamminedichloroplatinum(II) in nude mouse-grown human neuroblastoma.

The antitumor effect of combined use of cis-diamminedichloroplatinum(II) (CDDP) and verapamil, a calcium influx blocker, was examined in neuroblastoma transplanted to BALB/c athymic mice. The response of the tumor to CDDP was related to the dose administered. Regression of the tumor was observed when CDDP was administered at 4.2 mg/kg/injection. The retardation of tumor growth was observed in the group to which CDDP was administered at 2.1 mg/kg/injection. When verapamil was administered with CDDP, regression of the tumor was observed in the group treated with CDDP at 2.1 mg/kg/injection, and the retardation of tumor growth was observed in the group treated with CDDP at 1.4 mg/kg/injection. These results indicate that verapamil enhances the antitumor effect of CDDP against transplanted neuroblastoma in BALB/c athymic mice.

Animals↗
PubMed1987

Electrical measurement of fluid distribution in legs and arms.

Intra- and extra-cellular fluid distribution is very important to know the physiological and clinical state of living subjects. However, it is quite difficult to measure the distribution in vivo. Electrical impedance of living tissue is mainly affected by extra-cellular fluid at an applied frequency lower than the beta-dispersion frequency, and is affected by both extra- and intra-cellular fluid at higher applied frequencies than that. In this paper, we discuss the problems of measurement of intra- and extra-cellular fluid distribution in living tissues by means of electrical impedance. The intra- and extra-cellular fluid distribution is related to some physiological parameters, such as blood circulation, metabolism of tissues, and the electrolytic concentration of intra- and extra-cellular fluids. Therefore, the information about the distribution of fluids in tissues is quite useful for the diagnosis of various diseases, the monitoring of seriously ill patients, and in medical treatments such as artificial dialysis. We discuss the method of measurement and the results of experiments.

Arm↗
PubMed1987

Distinguishing the antigen specificities of pemphigus vulgaris and pemphigus foliaceus using the biotin-avidin immunofluorescence method.

To compare the specificities of autoantibodies in sera from patients with pemphigus vulgaris (PV) and those with pemphigus foliaceus (PF), blocking-immunofluorescence studies were carried out using the biotin-avidin immunofluorescence technique. First cryostat sections of bovine muzzle epidermis were incubated with one of either the unlabeled PV or PF serum samples for 2 h at room temperature, then rinsed and overlayered for 30 min with serially diluted corresponding or other biotin-labeled PV (or PF) IgG fractions containing their autoantibodies. The sections were then incubated for 30 min in fluorescein-labeled avidin. The blocking abilities of PV (or PF) sera for the reaction of labeled PV (or PF) IgG on the membranous part of keratinocytes were compared. The following results were obtained: the titers of biotin-labeled PF IgG decreased considerably more in sections preincubated with PF sera than sections preincubated with PV or normal sera. The titers of biotin-labeled PV IgG decreased considerably more in sections preincubated with PV sera than sections preincubated with PF or normal sera. These results suggest that there may be a distinction in antigenic specificities between PV and PF sera.

Autoantibodies↗
PubMed1987

Analysis of estrogen receptors in human breast cancer by assays using monoclonal antibodies and by the dextran-coated charcoal method.

Estrogen receptors (ER) were analyzed in 63 human breast cancers by immunocytochemical assay, and by enzyme-immunoassay, using monoclonal antibodies against human ER protein, and also by the dextran-coated charcoal method. The specific staining was observed only in the nucleus of cancer cells by the immunocytochemical assay, and the presence of nuclear staining by this assay was closely associated with the estimation of the cytosolic ER content by both the dextran-coated charcoal method and the enzyme-immunoassay. In the latter, the cytosolic ER content correspondingly increased with the nuclear ER content. Both the cytosolic and nuclear ER contents correlated well with those obtained by the dextran-coated charcoal method. Furthermore, the cytosolic ER contents obtained by the enzyme-immunoassay and the dextran-coated charcoal method correlated significantly with the age of the patient, but not with the nuclear ER contents. These above mentioned results suggest that ER is present mainly in the nucleus of breast cancer cells and that the cytosolic ER obtained by these two assays is the unoccupied one released from the nucleus.

Antibodies, Monoclonal↗
PubMed1987

Colorectal carcinoma in young adults.

Charts of 570 patients with colorectal carcinoma surgically treated in one institution during a 13 year period were retrospectively reviewed to evaluate clinicopathologic patterns and surgical results of those 39 years of age or under. Of the 570 patients, 57 (10 percent) were 39 years of age or under, and this group included more female patients than the older control group. Mucinous carcinoma was frequently found on histologic examination, with significantly high incidences of lymph node involvement, peritoneal dissemination, and advanced tumor stages by Dukes' classification in the young patients. The overall cumulative 5 year survival rate in the younger group was significantly lower than that in the control group (41 percent and 55.9 percent, respectively), whereas the difference in rates among the two groups for curative resection was not statistically significant (71.6 percent and 76.3 percent, respectively). Early diagnosis and attempts at curative resection are of utmost importance in the treatment of young patients with colorectal carcinoma.

Adenocarcinoma↗
PubMed1987

Effect of anticonvulsants on pentylenetetrazol-induced power spectrum changes in electroencephalograms in rats.

The effect of anticonvulsants on pentylenetetrazol (PTZ)-induced EEG power spectrum changes was examined. When the minimum dose of PTZ (15 mg/kg) was administered intravenously twice, with an interval of 80 min, a clear EEG power spectrum change was observed after the second PTZ administration, irrespective of whether or not the first PTZ administration evoked marked EEG changes. We defined the values F/N, S/N and S/F. The value F/N, obtained by dividing the power spectrum area after the first PTZ administration by the normal power spectrum area, was 1.06 +/- 0.05 (mean +/- S.E.). The value S/N, obtained by dividing the power spectrum area after the second PTZ administration by the normal power spectrum area, was 2.00 +/- 0.21. The value S/F, obtained by dividing S/N by F/N, was 1.86 +/- 0.16. The S/F value was almost constant regardless of whether or not the first PTZ administration could evoke marked EEG changes. The effect of anticonvulsants was examined by S/F value changes, and 100 mg/kg of PHT completely inhibited the double PTZ effect. Phenobarbital, ethosuximide and sodium valproate also inhibited the double PTZ effect. Using the S/F value of the EEG power spectrum with minimum dose double PTZ administration, quantitative evaluation is possible for anticonvulsant drugs.

Animals↗
PubMed1987

Some physical results from an impedance camera.

We discuss some physical results from an impedance camera. We placed agar blocks of various resistivities and sizes in saline. We showed that when the agar block was small or close in resistivity to the saline solution, we were unable to reconstruct it. We attempted to reconstruct an image of a fist, but were unable to achieve this due to current flowing in the arm. We concluded that three-dimensional analysis may be needed, along with more sensitive reconstruction algorithms and measurements.

Agar↗
PubMed1987

Beneficial effects of exercise on growth of rats during intermittent fasting.

An 8-wk trial was conducted to compare the effects of exercise and intermittent fasting, either singly or combined, on growth responses of rats. Four-week-old male Wistar rats, 85-110 g each, were assigned to one of four groups (n = 9): control, exercise on a motor-driven treadmill, fasting every other day (EOD) and fasting EOD and exercise combined. At the end of the trial, the exercised rats had consumed 7% less feed, had gained 7% less weight and had 36% less carcass fat than the control rats. Fasting on alternate days markedly reduced the growth rate of the young rats. Fasted-EOD rats weighed less than half as much as the control rats, had 64% less carcass fat and 51% less lean mass and had smaller livers, kidneys, hearts, tibias and tibialis anterior muscles. The addition of exercise to the fasting EOD regimen improved the growth of the animals. When the fasted-EOD rats were also exercised, they gained 29% more weight, consumed 11% more feed and had carcasses that contained 29% more lean mass and 18% less fat than the fasted-EOD rats. The data suggest that exercise may be beneficial where feed restriction is episodic, allowing some capacity for catch-up growth.

Animals↗
PubMed1987

Studies of the effects of FK506 on renal allografting in the beagle dog.

The immunosuppressive activities of a newly discovered macrolide extracted from Streptomyces tsukubaensis, FK506, were examined using 38 renal allografts in the beagle dog. The median survival time was 15.5 days in dogs without treatment, 61 days with a dose of 0.08 mg/kg/day and 176 days with a dose of 0.16 mg/kg/day of intramuscularly administered FK506. Prolongation of survival was statistically significant when compared with controls (P = 0.02, 0.0044, respectively). None of 6 recipient dogs receiving the agent at a dose of 0.16 mg/kg/day encountered rejection during the treatment course. Three of them survived over 200 days. Oral administration of FK506 at a dose of 0.32 mg/kg/day did not prolong the median survival time (20.5 days) compared with the placebo treated control (16.5 days), but oral treatment with 1.0 mg/kg/day resulted in all of the recipient dogs surviving over 130 days. Histological studies of 7 kidney graft biopsy specimens of the dogs surviving over 3 months revealed no cell infiltration or only some degree of reversible interstitial cell infiltration, but vascular and glomerular changes were not observed in any of the specimens. Irregularity of nuclear shape and cytoplasmic vacuolation of the pars recta of the proximal tubules were observed in one dog each. Liver biopsy specimens showed no consistent evidence of hepatocellular damage. Three dogs died of intussusception 2-3 weeks posttransplant. The dogs treated intramuscularly with 0.32 mg/kg/day suffered from anorexia. Two dogs receiving oral treatment at a dose of 1.0 mg/kg developed papilloma of the skin around day 60, but the tumors disappeared by day 120. We conclude that FK506 is a powerful immunosuppressant in the dog with tolerable side effects.

Administration, Oral↗