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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 109 records · Page 6Linked to original sources
PubMed2001

Pigmented Paget's disease of the male breast: report of a case.

An 83-year-old man with pigmented Paget's disease of the breast is reported. He had a blackish swollen right nipple with bloody discharge that lasted for 8 months. Histopathology of the lesion disclosed intraepidermal and dermal atypical cells forming small clusters and underlying intraductal carcinoma. Melanocytes were dispersed in the epidermis. Dermal melanophages were also detected. The atypical cells were positive for carcinoembryonic antigen, human-milk fat globule protein and a recently described new antigen, RCAS-1, but negative for S-100 or HMB-45. We diagnosed this case as Paget's disease of the male breast. Paget's disease of the breast is usually nonpigmented and occurs almost exclusively in women. Pigmented Paget's disease of the male breast is extremely rare, and only a few cases have been reported. Albeit rare, pigmented Paget's disease has to be included in the differential diagnosis of pigmented lesions of the nipple.

Aged↗
PubMed2001

Neuromuscular blocking effects of the aminoglycoside antibiotics arbekacin, astromicin, isepamicin and netilmicin on the diaphragm and limb muscles in the rabbit.

Aminoglycoside antibiotics are known to produce a depression of neuromuscular function which may cause prolonged paralysis of respiratory muscles. However, differences in the effects of aminoglycoside antibiotics on diaphragm and limb muscles have not been investigated. We determined the neuromuscular blocking effects of the aminoglycoside antibiotics arbekacin sulfate, astromicin sulfate, isepamicin sulfate and netilmicin sulfate on the diaphragm, tibialis anterior and soleus muscles in anesthetized rabbit nerve-muscle preparations. Neuromuscular block was assessed by mechanical response with single twitch stimulation. Cumulative drug dose-response curves were obtained for three different muscles in 24 rabbits. The mean ED(50) and ED(95) of the antibiotics in diaphragm, tibialis anterior and soleus muscles were calculated. The neuromuscular blocking effects of all the aminoglycosides on ED(50) and ED(95) values were in the order of soleus > tibialis anterior > diaphragm, and soleus > diaphragm > tibialis anterior, respectively. The ED(50) ratios for the tibialis anterior and soleus muscles were approximately 1.5 and 2.7 times greater than that for the diaphragm.

Aminoglycosides↗
PubMed2001

Effect of experimental renal dysfunction on bioavailability of ajmaline in rats.

The effect of renal dysfunction on the bioavailability of ajmaline has been investigated in rats, where experimental renal dysfunction was induced by subcutaneous injection of uranyl nitrate (10 mg kg(-1)). Renal dysfunction did not cause any change in the blood ajmaline concentration after intravenous administration (2 mg kg(-1)), but it increased the blood ajmaline concentration by approximately 2.8-fold after intraduodenal administration (10 mg kg(-1)). The availability of ajmaline in control rats was 16.7%, whereas the availability was increased to 41.1% in rats with renal dysfunction. The unbound fraction in the blood and the metabolic activity in the liver, was assessed with the 10000-g supernatant fraction and with isolated hepatocytes, respectively. The values were found to be similar in both groups. The blood concentration following intraportal infusion was only slightly increased in rats with renal dysfunction, but the hepatic first-pass extraction was infusion rate-dependent and saturable. The initial absorption rate of ajmaline from the small intestine in rats with renal dysfunction was significantly greater compared with control rats. These results indicated that the increased availability of ajmaline in renal dysfunction was mainly a result of partially saturated extraction in the liver, which was caused by an increased absorption rate in the intestine and non-linear extraction in the liver.

Absorption↗
PubMed2001

Thermostability of doubly glycosylated recombinant lysozyme.

We prepared a lysozyme mutant (Q41S/R61S) introducing Asn-type glycosylation signal sites by yeast expression system. On purification by cation exchange column at pH 7, three fractions were obtained. Peptide mapping and mass-spectrometry showed the fractions were the derivatives glycosylated at both Asn39 and Asn59, at only Asn39, and not glycosylated. It was revealed that the processing of Asn-linked oligosaccharide at Asn39 and Asn59 occurred independently in yeast cells. The denaturation temperatures of these derivatives by differential scanning calorimetry were 76.0, 68.8, and 67.5 degrees C at pH 3, respectively. The stabilization of glycosylated lysozyme depends on the degree of glycosylation. We concluded that stabilized proteins can be constructed by glycosylation at proper sites. Thermodynamic stabilization by the artificial double glycosylations on a protein has not yet been reported.

Electrophoresis, Polyacrylamide Gel↗
PubMed2001

Thymidine phosphorylase inhibitors with a homophthalimide skeleton.

Several N-phenylhomophthalimide derivatives were prepared and their inhibitory activity on thymidine phosphorylase/ platelet-derived endothelial cell growth factor (TP/PD-ECGF) was assessed. Among them, 2-(2,6-diethylphenyl)-7-nitro-1,2,3,4-tetrahydroisoquinoline-1,3-dione (9) was found to be a more potent inhibitor than the classical inhibitor, 5-nitrouracil (1). Lineweaver-Burk plot analysis indicated that 9 shows mixed-type competitive inhibition of TP/PD-ECGF, while 1 is a competitive inhibitor.

Endothelial Growth Factors↗
PubMed2001

Asymmetric synthesis of a 3-acyltetronic acid derivative, RK-682, and formation of its calcium salt during silica gel column chromatography.

RK-682 was reported to be a potent protein tyrosine phosphatase inhibitor. We found that (R)-3-hexadecanoyl-5-hydroxymethyltetronic acid (1) was easily converted to its calcium salt during column chromatography on Silica gel 60, and this calcium salt was identical to RK-682 originally isolated from a natural source. Here we report details of the asymmetric synthesis of (R)-1 and its conversion to the calcium salt. Fast atom bombardment mass spectrometric (FAB-MS) analysis of the free and calcium salt forms of RK-682 is also reported.

Calcium↗
PubMed2001

Novel retinoidal tropolone derivatives. Bioisosteric relationship of tropolone ring with benzoic acid moiety in retinoid structure.

Several tropolone derivatives (4-7) were designed as novel retinoids on the assumption that the tropolone ring may mimic the benzoic acid moiety in retinoid structures, such as Am80 (2). Among the synthesized compounds, 5-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)ethynyl]tropolone (7a) showed moderate potency as a differentiation-inducer of HL-60 cells. The activities of the tropolones were greatly enhanced in the presence of HX630, an RXR agonist (retinoid synergist).

Benzoates↗
PubMed2001

Alpha-glucosidase inhibitors with a 4,5,6,7-tetrachlorophthalimide skeleton pendanted with a cycloalkyl or dicarba-closo-dodecaborane group.

Previous studies of alpha-glucosidase inhibitors derived from thalidomide revealed that 4,5,6,7-tetrachloro-N-alkylphthalimide derivatives are superior lead compounds. Structure-activity relationship studies indicated that a hydrophobic group at the N(2) position is mandatory for potent activity. Accordingly, we have designed and synthesized some 4,5,6,7-tetrachloro-N-cycloalkylphthalimide and 4,5,6,7-tetrachloro-N-dicarba-closo-dodecaborane derivatives. The prepared compounds exhibited potent alpha-glucosidase-inhibitory activity. Among them, 4,5,6,7-tetrachloro-N-cycloheptylphthalimide (9) showed the most potent activity, being approximately 30 times more active than the classical inhibitor, 1-deoxynojirimycin (1).

Boranes↗
PubMed2001

Combination of N-methyl-1-deoxynojirimycin and ischemic preconditioning markedly reduces the size of myocardial infarcts in rabbits.

N-methyl-1-deoxynojirimycin (NMDN), an a-glucosidase inhibitor, reduces myocardial infarct size by reducing the glycogenolytic rate through inhibition of the alpha-1,6-glucosidase of glycogen-debranching enzyme in the heart, in addition to possessing an antihyperglycemic action by blocking alpha-1,4-glucosidase in the intestine. Ischemic preconditioning (PC), which markedly reduces the size of the myocardial infarct, is known to reduce the activity of phosphorylase and reduce the glycogenolytic rate. Therefore, it was hypothesized that a combination of pharmacological inhibition of glycogenolysis by an alpha-1,6-glucosidase inhibitor, NMDN, and PC could markedly reduce myocardial infarct size more than NMDN or PC alone. Japanese white rabbits without collateral circulation were subjected to a 30-min coronary occlusion followed by 48-h reperfusion. The infarct sizes as a percentage of area at risk were significantly reduced by pre-ischemic treatment with either 100mg/kg of NMDN or PC of 5 min ischemia and 5 min reperfusion alone (15.9+/-2.0%, n=8, and 10.3+/-1.2%, n=8, respectively) as compared with the control (43.9+/-2.2%, n=8). However, the combination of 100mg/kg of NMDN and PC significantly reduced the infarct size (4.9+/-1.2, n=8) compared with NMDN or PC alone. Another 40 rabbits, also given 100mg of NMDN, PC, NMDN+PC or saline before ischemia (n=10 in each group), were killed for biochemical analysis after 30 min of ischemia. NMDN and PC preserved the glycogen content and attenuated the lactate accumulation, respectively, as compared with the control. However, the combination of NMDN and PC preserved significantly more glycogen and significantly reduced lactate accumulation than either NMDN or PC alone. The combination of NMDN and PC markedly reduced the myocardial infarct size more than either process alone. The marked preservation of glycogen and marked attenuation of lactate accumulation by the combination of NMDN and PC suggest that the mechanism for this effect of NMDN+PC is related to the inhibition of glycogenolysis.

1-Deoxynojirimycin↗
PubMed2001

Reduction by phytate-reduced soybean beta-conglycinin of plasma triglyceride level of young and adult rats.

This study examined the effects of soybean beta-conglycinin, from which phytate was mostly removed, on the plasma lipids in young and adult rats. Male Wistar young (6 week-old) and adult (21 week-old) rats were fed high cholesterol diets containing 20% casein, soy protein isolate (SPI), or soybean beta-conglycinin for 10 days. In young rats, although the food intake of the beta-conglycinin group was higher than those of the casein and SPI groups, the weight gain was significantly lower than those of the other groups. However, in adult rats, the weight gain was not different among the groups. In young and adult rats, relative liver weights of SPI and beta-conglycinin groups were significantly lower than that of the casein group, and the degree of the reduction was more marked in the beta-conglycinin group than in the SPI group. In young rats, the plasma triglyceride level was significantly lower in the SPI and beta-conglycinin groups than that in the casein group. In addition, the plasma triglyceride level of the beta-conglycinin group was significantly lower than that of the SPI group. Plasma total cholesterol levels of the SPI and beta-conglycinin groups were significantly lower than that of the casein group. However, there was little difference in the lowering effect between SPI and beta-conglycinin. These results indicate that soybean beta-conglycinin may have lowering functions not only on plasma total cholesterol level, but also on plasma triglyceride level.

Aging↗
PubMed2001

Susac's syndrome: beneficial effects of corticosteroid therapy in a Japanese case.

Susac's syndrome is a rare disorder characterized by the triad of microangiopathy of the brain and retina with hearing loss. More than 50 affected individuals have been reported worldwide, all Caucasians. We herein identify the first Japanese patient with Susac's syndrome. A 36-year-old man developed recurrent subacute encephalopathy, bi- a lateral sensorineural hearing loss, and retinal arteriolar occlusions, caused by microangiopathy from a year previously. T2-weighted MRI showed multiple high-signal lesions ti predominantly in the periventricular white matter. During the exacerbated phase both high-dose intravenous methyl-prednisolone and oral prednisone therapy produced beneficial effects. He showed definite remission within 2 years from the disease onset.

Adult↗
PubMed2001

Transesophageal echocardiography for detection of cardiac diseases in patients with retinal artery occlusion.

OBJECTIVE: We analyzed the usefulness of transesophageal echocardiography (TEE) for detection of cardiac diseases in patients with retinal artery occlusion (RAO). PATIENTS AND METHODS: We retrospectively reviewed the charts of 22 consecutive patients with acute RAO. The patients had been evaluated by conventional studies, including transthoracic echocardiography (TTE) and TEE. RESULTS: TEE findings were abnormal in 13 (59%) of the 22 patients. The findings revealed a decrease of flow velocity in the left atrial appendage (n=7), atrial septal aneurysm (n=4), patent foramen ovale (n=2), spontaneous echo contrast (n=1), ascending aortic plaque (n=1) and left atrial thrombus (n=1). Evaluations, including TEE, disclosed cardiac abnormalities in 16 (73%) of these 22 patients. However, excluding the analysis by TEE, cardiac abnormalities were revealed in only 6 (27%) patients. CONCLUSION: In patients with RAO, TEE may be a useful examination for detecting potential cardiac diseases.

Adult↗
PubMed2001

Hodgkin's disease preceded by unique neurological symptoms.

This is the first case report of Hodgkin's disease (HD) which showed both remission and exacerbation of neurological signs before a confirmed diagnosis of HD. The episodes occurred three times and multiple lesions were involved. Immunoabsorption plasmapheresis and double filtration plasmapheresis were effective for the first episode, whereas, corticosteroids partly improved the second and third episodes. Fever and lymph node swelling were apparent afterward and she was diagnosed as having HD from a supraclavicular lymph node biopsy. The remaining neurologic deficits responded to chemotherapy and radiotherapy. The neurological symptoms were considered as a paraneoplastic syndrome of HD.

Adult↗
PubMed2001

Glycosylative inactivation of chalcomycin and tylosin by a clinically isolated Nocardia asteroides strain.

Studies on the susceptibility of pathogenic Nocardia to macrolide antibiotics, chalcomycin and tylosin, showed that most of the Nocardia species examined were highly resistant to both antibiotics, although N. nova was moderately susceptible. N. asteroides IFM 0339 converted these macrolides into inactive metabolites by glycosylation at 2'-OH or glycosylation and reduction of the 20-formyl group. The structures of the metabolites were determined from NMR and MS data to be 2'-[O-(beta-D-glucopyranosyl)]chalcomycin (2), 2'-[O-(beta-D-glucopyranosyl)]tylosin (5) and 20-dihydro-2'-[O-(beta-D-glucopyranosyl)]tylosin (4).

Anti-Bacterial Agents↗
PubMed2001

[Evaluation of off-pump coronary artery bypass grafting based on systemic inflammatory response syndrome].

Assessment of the less-invasiveness of off-pump coronary artery bypass grafting (OP-CAB) was made by the view point of systemic inflammatory response syndrome (SIRS). Single vessel OP-CAB with median sternotomy (MS(+)OP-CAB group, n = 13), single vessel OP-CAB without median sternotomy (MS(-)OP-CAB group, n = 9), two vessels conventional coronary artery bypass grafting (C-CAB) by normothermic extra corporeal circulation with steroid (methylprednisolone) (s(+)C-CAB group, n = 13), and two vessels C-CAB without steroid (s(-)C-CAB group, n = 13) were compared with each other. The criteria for SIRS was two or more of the following conditions: (1) temperature > 38.0 degrees C, (2) respiratory rate > 20 breaths/min, (3) heart rate > 90 beats/min, (4) white blood cells > 12,000 cells/mm3. Patients' date such as age, sex, risk factors, ejection fraction, operation time, aortic or LAD clamping time, frequency of SIRS, duration of SIRS, total application number of SIRS, mean application number of SIRS, hospitalization period, rate of renal or liver dysfunction were compared, and the following results were obtained. 1) MS(+)OP-CAB group had less-invasiveness than s(-)C-CAB group. The invasiveness of extra corporeal circulation was clear. 2) s(+)C-CAB group had equal invasiveness to MS(+)OP-CAB group. The anti-SIRS effect and organ protect effect of steroid was suggested. 3) MS(-)OP-CAB group had equal invasiveness to MS(+)OP-CAB group. The invasiveness of median full sternotomy was not so strong.

Aged↗
PubMed2001

[Treatment for recurrent paradoxical brain embolism through the patent foramen ovale].

We report here two patients with recurrent paradoxical brain embolism through the patent foramen ovale(PFO). The TIAs, which occurred frequently under antiplatelet therapy, resolved soon after commencing the anticoagulation therapy. Case 1, a 57-year-old woman, was diagnosed as having lacunar brain infarction and was treated with ticlopidine hydrochloride. Eleven months later, she suffered from frequent TIAs. Anticoagulation therapy was started after the presence of PFO was documented on transesophageal echocardiography(TEE). Thereafter, her TIA disappeared. Case 2 was a 67-year-old man with a history of lacunar brain infarction. Although he was treated with aspirin for 9 months, he showed transient monoplegia in his right leg. His TEE study also revealed the presence of PFO. After the anticoagulation therapy reached the proper level(PT-NR = 2), he never experienced the recurrence of TIA. If the antiplatelet therapy failed to prevent the recurrence of TIA, it is recommended to find out the presence of PFO which is a potential source of paradoxical brain embolism. In such a case, anticoagulation therapy should be instituted.

Aged↗