Biomedical subjects

S Hamano

Publications and source records attributed to S Hamano.

At least 73 records · Page 4Linked to original sources

PubMed1997

Possible involvement of intracellular Ca2+ in hyposmosis-evoked catecholamine release from adrenal chromaffin cells.

The influence of hyposmotic conditions on catecholamine release was studied using cultured adrenal chromaffin cells. Incubation of the cells in hyposmotic solution led to the enhancement of catecholamine release in a manner dependent on the reduction of osmolarity. Hyposmosis-evoked catecholamine release was similarly observed in the presence or absence of extracellular Ca2+, and was not significantly affected by organic and inorganic Ca2+ entry blockers. These results indicated that the hyposmosis-evoked release might be associated with a rise in the intracellular Ca2+ concentration. Further studies showed that neither ryanodine nor thapsigargin caused any significant effect on hyposmosis-evoked catecholamine release, whereas pretreatment of chromaffin cells with carbonyl cyanide m-chlorophenyl hydrazone significantly enhanced the hyposmosis-evoked release. Catecholamine release evoked by exposure to hyposmotic medium is therefore thought to be mediated through intracellular Ca2+, which may be mainly sequestered by the mitochondrial pools. Neither caffeine- nor inositol 1,4,5-trisphosphate-sensitive Ca2+ pools seems likely to be involved in hyposmosis-evoked catecholamine release, although the Ca2+ pools that contribute to the elevation of intracellular Ca2+ observed under hyposmotic conditions are not yet completely identified.

Adrenal Medulla↗

PubMed1997

The characterization of testicular cell (TC)-specific T-cell clones induced by intratesticular Listeria monocytogenes infection: TC-specific T cells with atypical cytokine profile transfer orchitis.

A unilateral infection of Listeria monocytogenes into the testis of mice induces not only Listeria-specific T cells but also autoreactive T cells that can transfer experimental autoimmune orchitis (EAO) into naive mice. To investigate the characteristics of the autoreactive T cells, we established six testicular cell (TC)-specific T-cell clones from the spleen of the intratesticularly infected mice. All the clones expressed CD4 and T-cell receptor (TCR) alpha beta, and four of the six clones expressed V beta 8. They showed proliferative response to TC in the presence of syngeneic spleen antigen-presenting cells, but did not cross-react to Listeria antigen (Ag). They produced interferon-gamma (IFN-gamma) when stimulated with TC, but interleukin-2 (IL-2), IL-4 and IL-10 were undetectable. IL-2 production was not detected even when they were restimulated with TC after a 10-day resting culture without Ag and IL-2, although they proliferated in the restimulation culture. Even in the presence of anti-IL-2 mAb, the TC-specific T-cell clones showed proliferative response against TC. The observations indicate that the TC-specific IFN-gamma-producing T cells proliferate in the absence of autocrine. Both intravenous and intratesticular injection of these clones transferred EAO in syngeneic naive mice. These results suggest that L. monocytogenes infection in the testis induces autoreactive orchitogenic CD4+ T cells without cross-reactivity to bacterial Ag. Furthermore, these data demonstrate that CD4+ T cells with an atypical cytokine profile can efficiently cause EAO.

Adoptive Transfer↗

PubMed1997

Macrophages activated by Listeria monocytogenes induce organ-specific autoimmunity.

We have previously reported an experimental autoimmune model induced by the local infection of Listeria monocytogenes. The unilateral inoculation of virulent Listeria into a testis of a normal mouse induced a delayed-type hypersensitivity response against testicular antigen and caused autoimmune orchitis in the contralateral testis. The orchitis was transferred to naive mice by T cells from the intratesticularly infected mice. In this paper, we demonstrated that avirulent Listeria, which lacks the expression of listeriolysin O, failed to induce any anti-testicular responses or contralateral orchitis even when it was inoculated at a high dose into the testis. Furthermore, the intraperitoneal inoculation of virulent Listeria with testicular antigen induced the anti-testicular responses and orchitis although intraperitoneal inoculation of testicular antigen with avirulent Listeria failed to induce them. The difference between virulent and avirulent Listeria in the induction of anti-testicular responses was supposed to be dependent on the difference in macrophage activation by the two bacterial strains because, first, the anti-testicular responses were elicited in normal mice when macrophages from virulent Listeria-infected mice were intraperitoneally transferred with testicular antigen although no viable bacteria were detected from the macrophages, and secondly, in contrast, the intraperitoneal co-inoculation of macrophages from avirulent Listeria-infected mice and testicular antigen failed to elicit any anti-testicular responses. Finally, we found that the virulent Listeria-induced macrophages expressed a higher level of CD80 (B7-1) and CD86 (B7-2) molecules than did the avirulent Listeria-induced macrophages and naive peritoneal macrophages. These results thus suggest that virulent Listeria activates macrophages to induce autoreactive T cells while avirulent Listeria does not. The up-regulation of B7 molecules by virulent Listeria infection is a candidate of the mechanism for the activation of autoreactive T cells.

Animals↗

PubMed1997

Rapid enlargement of cardiac rhabdomyoma during corticotropin therapy for infantile spasms.

OBJECTIVE: To investigate the influence of corticotropin therapy on cardiac rhabdomyoma. DESIGN: Analysis of data from echocardiography performed on in-patients. PATIENTS: Six patients with rhabdomyoma who were admitted to the authors' medical centre with either convulsion (five cases) or prematurity (one case) between 1985 and 1995. Five had tuberous sclerosis. INTERVENTION: Size of cardiac tumours of each patient was measured by echocardiography, and volume index was calculated as the ratio of the tumour volume to its initial volume. MAIN RESULT: Increase in size of some of the tumours was found during corticotropin therapy on follow-up echocardiography. Maximum volume indexes of tumours in the case of patients (n = 4) who did not receive corticotropin therapy was 1.2 to 3.7, whereas those of patients (n = 2) who received therapy was 9.1 to 12; one of the latter patients died. CONCLUSION: Corticotropin may contribute to the enlargement of cardiac rhabdomyoma. The size of cardiac rhabdomyomas must be carefully followed when patients are treated with corticotropin.

Adrenocorticotropic Hormone↗

PubMed1997

[Effect of estramustine phosphate on hormone refractory prostate cancer].

Clinical effects of estramustine phosphate (EMT) on hormone refractory prostate cancer were studied. Prostate cancer relapsed in 70 of the 259 patients with stage C and D diseases who had initially responded to endocrine therapy. After cancer relapse, endocrine therapy was changed to oral administration of EMT in 21 patients, while initial endocrine therapy was continued in 14 and additional radiation therapy was given in 35. A partial response or no change was observed in 11 of the 21 patients (52%) given EMT therapy, the mean duration of the response being 14.2 months. The 21 patients given EMT therapy survived significantly longer than the 14 patients with continued on endocrine therapy, and those responding to EMT therapy tended to have a better survival than those unresponsive. Side effects of EMT included loss of appetite in 2 patients and edema of the lower limb in 1, but they were not severe enough to require discontinuation of the drug. EMT may be a useful drug for patients with advanced prostate cancer with relapse after endocrine therapy.

Administration, Oral↗

PubMed1997

[A case of PEHO (progressive encephalopathy with edema, hypsarrhythmia and optic atrophy) syndrome: changes in clinical and neuroradiological findings].

We reported serial clinical, radiological, and neurophysiological findings of a patient with PEHO (progressive encephalopathy with edema, hypsarrhythmia and optic atrophy) syndrome. The case was a 4-year-and-8-month-old boy. He had no apparent problems during pregnancy, but after his birth severe hypotonia and developmental delay were evident. Infantile spasms appeared at 3 months of age, and progressive opisthotonic posture and loss of his visual acuity at 8 months. Eye fixation was lost, and optic atrophy was observed. Seizures and progressive atrophy of the cerebellum and brainstem developed during the same period. These findings of our case support the hypothesis that brainstem lesions are related to infantile spasms.

Brain Diseases↗

PubMed1997

[Fulminant subacute sclerosing panencephalitis: clinical and neuropathological observations].

We describe a 3-year-old boy with subacute sclerosing panencephalitis (SSPE) who died 4 months after its onset. His initial symptoms were drowsiness and left hemiplegia. He became comatose in 10 days, and developed a decortical posture after 45 days. He suffered from multiple cerebral hemorrhage and infarction 3 months later. Oligodendrocytes were positively stained by immunocytochemical stain with a complement-fixing measles antibody. Light microscopy revealed glial nodules, perivascular cuffing and reactive gliosis. Small arteries showed intimal thickening with resultant occlusion and occasional recanalization. These findings suggested vascular involvement in SSPE. This case illustrates the difference between the fulminant and chronic forms of SSPE.

Brain↗

PubMed1996

Tranilast suppresses the vascular intimal hyperplasia after balloon injury in rabbits fed on a high-cholesterol diet.

Intimal hyperplasia is a serious problem after percutaneous transluminal coronary angioplasty. In this study, we assessed the effect of tranilast on vascular intimal hyperplasia after balloon injury in rabbits fed on a high-cholesterol diet. In this animal model, intimal hyperplasia more severe than that in rabbits fed on a normal diet was observed. In addition, medial thickening and lipid deposits in both media and intima were also noted. These findings indicate that balloon injury caused intimal and medial hyperplasia and that this hyperplasia was accelerated by the high cholesterol load. Tranilast (300 mg/kg) significantly decreased the intimal area, medial area, and stenosis ratio, and increased the luminal/total area ratio, in the cholesterol-fed rabbits. These results suggest that tranilast may be useful for prevention of restenosis after percutaneous transluminal coronary angioplasty of patients, including those with a clinical risk of hypercholesterolemia.

Animals↗

PubMed1996

Effect of B-mercaptoethanol on the viability of IVM/IVF/IVC bovine embryos during long-distance transportation in plastic straws.

Experiments were conducted to assess the effect of beta-mercaptoethanol (beta-ME) on the quality and viability of bovine blastocysts derived from in-vitro culture (IVC) of in-vitro matured and fertilized (TVM-IVF) oocytes during their transport between 2 distant places. Follicular oocytes were collected from ovaries obtained at a slaughterhouse and were cultured for 20 to 21 h in modified TCM-199. The IVM oocytes were fertilized in vitro with frozen-thawed spermatozoa. Fertilized oocytes were cultured for 7 d, and embryos that developed to the blastocyst stage were used for the experiments. The blastocysts, packed in straws with transportation medium that consisted of modified TCM-199 with HEPES equilibrated in air and supplemented with 20 % calf serum and 0, 10, 50, 100 or 150 microM beta-ME, were transported at 37 degrees C from Tokyo to Sapporo by air (18.3 h). The quality of blastocysts was assessed and ranked as excellent (A), good (B), fair (C) or poor (D) after transportation. The percentages of blastocysts ranked as A or B were significantly higher (P < 0.05) when the embryos were transported in beta-ME supplemented medium (80 to 100%) than when transported without beta-ME (54 %). Blastocysts ranked as A or B after transportation in medium with or without 150 microM beta-ME were nonsurgically transferred to synchronous recipients; 60 d after embryo transfer, 21/36 and 19/35 cows, respectively, were diagnosed as pregnant by palpation per rectum. These results indicate that beta-ME maintains the quality of bovine blastocysts in plastic straws for several hours without control of CO2 and that the concentration of beta-ME used in this experiment is not detrimental to the blastocysts.

Journal Article↗

PubMed1996

Interstitial duplication 8q22-q24: report of a case proven by FISH with mapped cosmid probes.

We report on a 6-month-old malformed female infant with a de novo interstitial duplication of an 8q22-q24 segment. She had an excess dark-band on the 8q distal region by GTG-banded chromosome analysis, which was likely to be 8q23. We performed FISH analysis using cosmid probes mapped to 8q23 and proved that the patient had an 8q duplication including the 8q23 region.

Chromosome Banding↗

PubMed1996

Tranilast antagonizes angiotensin II and inhibits its biological effects in vascular smooth muscle cells.

Recent studies have been reported indicating that angiotensin II may potentiate neointimal formation. In the present study, we examined the antagonistic effect of tranilast on angiotensin II. Losartan was used as the reference compound. First, tranilast inhibited the angiotensin II-induced contraction of rabbit aortic strips in a noncompetitive manner (pD'(2) = 3.7), whereas it had little effect on the contraction induced by noradrenaline or endothelin-l. Second, tranilast inhibited the binding of (125)I-labeled angiotensin II to angiotensin AT1 receptors in rat liver membranes with an IC(50) value of 289 mu M. Finally, functional antagonism of tranilast (100 and 300 mu M) was demonstrated by its blockade of angiotensin II (10(-8)M)-induced (45)Ca(2+) -efflux from human vascular smooth muscle cells (VSMC). However, tranilast (30-300 mu M) exerted no influence on PDGF-induced formation of inositol triphosphates which cause an increase in [Ca(2+)]i in human VSMC. The antagonistic activity of tranilast towards angiotensin II may be involved in part in preventing restenosis after percutaneous transluminal coronary angioplasty (PTCA).

Angiotensin II↗

PubMed1996

IL-3 derived from CD4+ T cells is essential for the in vitro expansion of mast cells from the normal adult mouse spleen.

A null cell line (SCM1) was established by a culture of spleen cells (SC) from normal adult C57B1/6 mice with complete medium alone for 10 days and followed by weekly cultures with a 25% WEHI-3 cell culture supernatant. Phenotype analysis showed that the SCM1 cells were negative for CD3, Thy1.2, B220, Mac-1, Gr-1, NK1.1 and MHC class II, but were positive for MHC class I, Fc gamma RII/ III, Fc epsilon RI, c-kit and the receptor against wheat germ agglutinin. These findings suggested that the SCM1 cells were mast cells. In an in vitro proliferation assay. SCM1 cells proliferated in the presence of either IL-3 or stem cell factor (SCF), but not in the presence of IL-4, whereas IL-4 showed an augmenting effect on their proliferation in the presence of either IL-3 or SCF. In analysing the mechanism by which such mast cells could be expanded from normal adult mouse SC, the addition of anti-IL-3 MoAb, but not anti-SCF MoAb, into the initial culture inhibited the subsequent expansion of either IL-3-or SCF-responding cells. The prior depletion of CD4+ T cells abrogated the capacity of the SC to enhance the expansion of SCF-responding cells, and this inability was restored by the addition of IL-3. Moreover, the culture supernatant of normal adult SC alone contained considerable levels of IL-3. Taken together, our findings suggest that, in an in vitro culture, CD4+ T cell-derived IL-3 therefore enhances the expansion of mast cells from the normal adult mouse spleen.

Aging↗

PubMed1996

Antiproliferative and c-myc mRNA suppressive effect of tranilast on newborn human vascular smooth muscle cells in culture.

1. Newborn human vascular smooth muscle cells (VSMCs) proliferated faster and were more sensitive to platelet-derived growth factor-BB (PDGF-BB) than those from adults. In this study, we investigated mechanism of the inhibitory effect of tranilast on PDGF-BB-induced proliferation of VSMCs from newborns. 2. Tranilast (30-300 microM) concentration-dependently inhibited the VSMC proliferation in randomly growing cultures stimulated with PDGF-BB. 3. Tranilast (30-300 microM) concentration-dependently inhibited the [3H]-thymidine incorporation into DNA in VSMCs that had been synchronized by 48 h serum depletion and then stimulated by addition of PDGF-BB. However, tranilast had little influence on unscheduled DNA synthesis in quiescent cells or on RNA and protein synthesis, unlike aphidicolin, actimomycin D, and cycloheximide. 4. In synchronized VSMC cultures, tranilast still inhibited the PDGF-BB-induced DNA synthesis even when added 18 h after stimulation of the quiescent cells. The mode of the antiproliferative action of tranilast was different from that of NiCl2, genistein, or staurosporin. In addition, flow cytometry of synchronized VSMCs treated with tranilast revealed a blockade of PDGF-inducible cell-cycle progression at the G1/S checkpoint. 5. Northern blotting showed that tranilast (30-300 microM) concentration-dependently suppressed constitutive c-myc mRNA expression even when added 18 h after PDGF-BB-stimulation of quiescent VSMCs. Tranilast still had an inhibitory effect on the induction of c-myc mRNA when de novo protein synthesis was inhibited by cycloheximide and did not shorten the degradation of c-myc mRNA at the post-transcriptional level, demonstrating that tranilast directly inhibited c-myc mRNA expression at the transcriptional level. 6. These results suggest that the inhibitory effect of tranilast on PDGF-BB-induced proliferation is due to S-phase blockade and may be, at least in part, involved in the direct suppression of c-myc gene expression. Tranilast did not cause cell toxicity and may therefore hold promising potential for the prevention of vascular proliferative diseases.

Adult↗

PubMed1996

Tranilast suppresses intimal hyperplasia in the balloon injury model and cuff treatment model in rabbits.

Intimal hyperplasia is a serious problem after percutaneous transluminal coronary angioplasty (PTCA). In this study, we investigated the effects of tranilast on intimal hyperplasia in both in vivo and in vitro experiments. For the in vivo experiments, we used the balloon injury model and the cuff treatment model of rabbits fed regular chow. In the balloon injury model, tranilast decreased intimal area, intima/media ratio, stenosis ratio and vascular DNA content after endothelial injury. Also in the cuff treatment model, tranilast suppressed the intimal hyperplasia. In the in vitro experiments, we assessed the effects of tranilast on platelet-derived growth factor-induced rabbit vascular smooth muscle cell (VSMC) migration and proliferation and on collagen synthesis by VSMCs. Tranilast inhibited VSMC migration, proliferation and collagen synthesis. These results suggest that tranilast has a suppressive effect on intimal hyperplasia after a vascular injury such as PTCA.

Angioplasty, Balloon, Coronary↗

PubMed1996

A rapid- and short-acting hypoglycemic agent KAD-1229 improves post-prandial hyperglycemia and diabetic complications in streptozotocin-induced non-insulin-dependent diabetes mellitus rats.

We investigated therapeutic effects of a rapid- and short-acting non-sulfonylurea hypoglycemic agent, calcium (2S)-2-benzyl-3-(cis-hexahydro-2-isoindolinylcarbonyl)propionate dihydrate (KAD-1229), on streptozotocin (STZ)-induced non-insulin-dependent diabetes mellitus (NIDDM) rats. The effects exerted by KAD-1229 on the post-prandial plasma glucose rise in STZ-induced mild NIDDM (mNIDDM) rats were different from those of sulfonylureas. When KAD-1229 with liquid meal (10 kcal/kg) was given to the mNIDDM rats, the plasma glucose migration was similar to that of normal healthy rats. On the contrary, glibenclamide had little or no effect on the plasma glucose rise 0.5-1 hr after oral administration, and its effect was only evident 2-5 hr after dosing. Tolbutamide showed similar hypoglycemia to that induced by glibenclamide at 2-5 hr with insufficient efficacy at 0.5 hr. Gliclazide sufficiently suppressed the level of post-prandial plasma glucose. However, its complete inhibition of post-prandial plasma glucose was associated with the extra-hypoglycemia 1-5 hr after oral administration. We also tested the efficacy of KAD-1229 in more severe STZ-induced NIDDM (sNIDDM) rats to elucidate the effects of the drug on the long-term glycemic controls and diabetic complications. When the sNIDDM rats were treated with 10 mg/kg KAD-1229 twice a day for about 17 weeks, increases in fasting plasma glucose and hemoglobin A1c were inhibited. Furthermore, treatment with KAD-1229 suppressed the development of microalbuminuria and cortical cataract. We conclude that the rapid- and short-acting insulinotropic agent KAD-1229 is able to improve the deterioration in the glycemic controls and inhibit the development of diabetic complications in STZ-induced NIDDM rats.

Albuminuria↗

PubMed1996

Multiple burr-hole operation for adult moyamoya disease.

Excellent results from multiple burr-hole operations for adult moyamoya disease are reported in this study. Ten patients had between one and four burr holes (mean 2.1) drilled in each hemisphere. In four patients new burr holes were added on the opposite side after depression of cerebral blood flow (CBF) was detected by follow-up single-photon emission computerized tomography imaging of the brain with N-isopropyl-p-[123I]iodoamphetamine. The postoperative follow-up period ranged from 6 to 62 months (mean 34.7 months). Beginning at 6 months postsurgery, angiograms disclosed rich neovascularization at 41 of 43 burr holes, first from the middle meningeal artery, then from the superficial temporal artery. Neovascularization did not occur at two burr holes at which there was subdural effusion and local cerebral atrophy, respectively. Progression of stenosis of the major vessels was seen in six patients. Moyamoya vessels were decreased at six sites in four patients. The CBF study revealed that the reactivity to acetazolamide improved in all six patients tested. Transient ischemic attacks disappeared in all six patients presenting with this symptom, and preoperative symptoms improved in both of the patients who presented with cerebral infarction and in both patients with intraventricular hemorrhage. There was no mortality or morbidity, and no new neurological deficits or rebleeding developed during the follow-up period. The authors strongly recommend the multiple burr- hole operation as the surgical treatment of choice for adult moyamoya disease because of its safety and effectiveness.

Adult↗

PubMed1996

[MRI findings of anterior spinal artery syndrome in childhood].

We reported two cases of anterior spinal artery syndrome in childhood evaluated by MRI of the spinal cord. The T2-weighted MRI revealed high signal intensity in the anterior region of spinal cord in both cases. These findings might be related with edema of the ischemic region. Several years later, the regions of the spinal cord showed atrophic changes. The high signal intensity on the T2-weighted MRI was characteristic of the anterior spinal artery syndrome.

Arteries↗

PubMed1996

[Vesico-acetabular fistula occurring 10 years after total hip replacement].

An 85-year-old female, who had had a total hip replacement for osteoarthritis in 1985, presented with gross hematuria in June 1995. Cystoscopy revealed a non-papillary sessile tumor in the right side wall of the urinary bladder with a crateriform opening on the top. Computed tomographic (CT) scan and excretory urography demonstrated a fistulous communication between the bladder and the acetabular bed filled with cement. The biopsy of the mass lesion suggested inflammatory granuloma with powdered cement. Since the lesion was composed of internal fistula, and was not accompanied with infection, the patient was treated conservatively. No external fistula had formed during the 5 months of observation.

Acetabulum↗