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Biomedical subjects

Y Hamamoto

Publications and source records attributed to Y Hamamoto.

At least 19 recordsLinked to original sources
PubMed2001

Regressive effect of intralesional injection of a moderate dose of recombinant interleukin-2 on carcinoma erysipeloides from gastric carcinoma.

Cutaneous metastatic diseases remain nearly incurable and a major medical challenge. It has been shown that interleukin-2 (IL-2) has potential as a therapeutic agent for various neoplastic diseases such as melanoma, renal cell carcinoma and myeloid leukaemia. However, IL-2 therapy for metastatic skin lesions has not been established yet. In the present study, we investigated the effect of recombinant IL-2 in a 79-year-old Japanese man with carcinoma erysipeloides, a rare type of cutaneous metastasis from gastric cancer. He was treated with an intralesional injection of rIL-2 (200 000 JRU) daily. Ten days after treatment, an erythematous plaque was eliminated almost completely leaving light brown pigmentation. A skin biopsy from the pigmented area revealed the absence of obvious tumour cells. These findings suggest that this cytokine should be considered for the clinical treatment of several inoperative metastatic cutaneous diseases, including gastric cancer.

Adenocarcinoma↗
PubMed2001

Fixed drug eruption due to clarithromycin.

Clarithromycin is one of the macrolide antibiotics used for cutaneous and respiratory system infections. Only a few cases of adverse cutaneous reactions to this drug have been reported. Here we report a rare case of clarithromycin-induced fixed drug eruption which could be reproduced by a peroral provocation test, whereas patch tests on both unaffected and residual pigmented skin yielded negative results. All cutaneous lesions that recurred due to the challenge test developed the same pigmentation after a short course of intravenous corticosteroid.

Aged↗
PubMed2000

The insulinotropic mechanism of the novel hypoglycaemic agent JTT-608: direct enhancement of Ca(2+) efficacy and increase of Ca(2+) influx by phosphodiesterase inhibition.

We examined the effects of the novel hypoglycaemic agent JTT-608 [trans-4-(4-methylcyclohexyl)-4-oxobutyric acid] on insulin secretion using rat pancreatic islets, and analysed the mechanism of its effect. JTT-608 augmented 8.3 mM glucose-induced insulin secretion dose-dependently, and there was a stimulatory effect of 100 microM JTT-608 at both moderate and high concentrations (8.3, 11. 1 and 16.7 mM) of glucose, but not at low concentrations (3.3 and 5. 5 mM). In perifusion experiments, both phases of insulin release were enhanced, and the effect was eliminated 10 min after withdrawal of the agent. In the presence of 200 microM diazoxide and a depolarizing concentration (30 mM) of K(+), there was an augmentation of insulin secretion by 100 microM JTT-608, not only under high levels of glucose but also under low levels, and the effects were abolished by 10 microM nitrendipine. JTT-608 augmented insulin secretion from electrically permeabilized islets in the presence of stimulatory concentrations (0.3 and 1.0 microM) of Ca(2+), and the intracellular Ca(2+) concentration ([Ca(2+)](i)) response under 16.7 mM glucose, 200 microM diazoxide, and 30 mM K(+) was also increased. The cyclic AMP content in the islets was increased by 100 microM JTT-608, and an additive effect to 1 microM forskolin was observed, but not to 50 microM 3-isobutyl-1-methylxanthine (IBMX). JTT-608 inhibited phosphodiesterase (PDE) activity dose-dependently. We conclude that JTT-608 augments insulin secretion by enhancing Ca(2+) efficacy and by increasing Ca(2+) influx. This appears to be a result of the increased intracellular cyclic AMP concentration due to PDE inhibition.

Animals↗
PubMed2000

Melanotic neuroectodermal tumor of infancy in the mandible: report of a case.

A case of melanotic neuroectodermal tumor of infancy occurring in the mandible is described. The patient was a 1-month-old boy with a rapidly growing tumor of the mandible. Computed tomography showed 2 well-defined osteolytic lesions in the right mandible. Histopathologic diagnosis of a biopsy specimen was melanotic neuroectodermal tumor of infancy. The tumor was excised with removal of the surrounding bone, but 1(1/2) months later it recurred, and segmental mandibulectomy and reconstruction of the defect with a titanium miniplate was performed. Retrospectively, evidence of recurrence was noted on computed tomography taken on the tenth postoperative day. The recurrence was caused by incomplete removal of the tumor. Histopathologically, the tumor cells of the recurrent lesion were dispersed extensively in the bone marrow, and bone remodeling was active. The surgical procedure may have stimulated tumor cell proliferation and reactive bone formation. The patient was followed for 2 years with no evidence of recurrence or metastasis.

Humans↗
PubMed2000

Benign symmetrical lipomatosis of the hands.

Benign symmetrical lipomatosis (BSL) is a disease characterized by massively symmetrical fat deposits predominantly in the neck and shoulder girdle area. The disease is frequently associated with alcoholism, hepatopathy, glucose intolerance, hyperuricemia, and malignant tumors. We describe a patient with BSL of the dorsal surfaces of both hands.

Diagnosis, Differential↗
PubMed2000

Augmentation of basal insulin release from rat islets by preexposure to a high concentration of glucose.

We have found that preexposure to an elevated concentration of glucose reversibly induces an enhancement of basal insulin release from rat pancreatic islets dependent on glucose metabolism. This basal insulin release augmented by priming was not suppressed by reduction of the intracellular ATP or Ca(2+) concentration, because even in the absence of ATP at low Ca(2+), the augmentation was not abolished from primed electrically permeabilized islets. Moreover, it was not inhibited by an alpha-adrenergic antagonist, clonidine. A threshold level of GTP is required to induce these effects, because together with adenine, mycophenolic acid, a cytosolic GTP synthesis inhibitor, completely abolished the enhancement of basal insulin release due to the glucose-induced priming without affecting the glucose-induced increment in ATP content and ATP-to-ADP ratio. In addition, a GDP analog significantly suppressed the enhanced insulin release due to priming from permeabilized islets in the absence of ATP at low Ca(2+), suggesting that the GTP-sensitive site may play a role in the augmentation of basal insulin release due to the glucose-induced priming effect.

Adenosine Triphosphate↗
PubMed2000

An immunohistochemical study of cytokeratins in skin-limited amyloidosis.

The frequency of amyloid deposits in cases of seborrheic keratosis was investigated In addition, the origin of amyloid protein(s) in lichen amyloidosis, macular amyloidosis and seborrheic keratosis was studied by immunohistochemical staining using a panel of anti-cytokeratin (CK) monoclonal antibodies. Amyloid deposits were found in 41 of 327 specimens (12.5%) from 301 cases of seborrheic keratosis. Amyloid deposits in seborrheic keratosis reacted with 6 of 12 CK antibodies and in lichen and macular amyloidosis (20 specimens) reacted with 5 of 12 CK antibodies. In seborrheic keratosis, antibody DE-K10 (labeling CK10) reacted with amyloid in 17 of 36 cases, antibody 34betaE12 (labeling CK1, 5, 10, 14) reacted in 33 of 39 cases, and antibody MNF116 (labeling CK5, 6, 8, 17) reacted in 32 of 35 cases. Among 20 specimens from lichen and macular amyloidosis, the three antibodies reacted with amyloid in the following rates: 1 with antibody DE-K10, all 20 with antibody 34betaE12, and 6 with antibody MNF116. These results suggest that amyloid deposits in seborrheic keratosis and lichen and macular amyloidosis may derive from epidermal cytokeratins.

Adult↗
PubMed2000

Hyperreactivity of pseudoxanthoma elasticum-affected dermis to vitamin D3.

A 68-year-old woman with pseudoxanthoma elasticum (PXE) was treated with oral vitamin D(3). After 2 weeks, new papules developed on the pre-existing plaques. Biopsy specimens of a fresh papule showed more abundant calcium deposition than before therapy. Electron microscopy revealed electron-lucent areas, which suggested unusual mineralization. From these findings, we propose that in patients with PXE, certain cutaneous tissues are highly sensitive to vitamin D(3), resulting in microdeposition of calcium salts.

Aged↗
PubMed2000

[A case of traumatic priapism].

We report a case of high flow priapism secondary to arteriovenous fistula produced by perineal trauma in a 43-year-old patient. Diagnosis was based on the result of gasometry in cavernous blood and color doppler sonography. Superselective embolization of the deep artery of the penis was performed with good results. After 6 months of treatment, erection and sexual function were normal. Our case demonstrates that this procedure is a safe and effective therapy for high flow priapism.

Adult↗
PubMed1999

Distinctions between microglial cells and peripheral macrophages with regard to adhesive activities and morphology.

Activated microglial cells and peripheral macrophages are hardly distinguishable from the viewpoints of morphology and function. There are various immunological markers common to both microglial cells and peripheral macrophages. In the present study, however, we found that microglial cells have distinct characters in terms of adhesion and morphology. By using a "rheoscope," that is an apparatus to rheologically measure the strength of cell adhesion to substrates, rat microglial cells were found to attach to polystyrene dishes much more weakly than alveolar and peritoneal macrophages. Interferon-gamma (IFNgamma) strengthened the adhesion of alveolar and peritoneal macrophages, whereas it weakened that of microglial cells. Morphological changes of microglial cells induced by IFNgamma were also different from those of peripheral macrophages. Furthermore, alveolar and peritoneal macrophages produced NO in response to IFNgamma, while microglial cells did not. When cultured on astrocyte-derived extracellular matrix (AsECM) in serum-free medium, only microglial cells extended multiple ramified processes. Conversely, alveolar and peritoneal macrophages on AsECM shrunk their ruffling membrane and rounded up. These distinctions between microglial cells and macrophages may reflect differences in cell lineages as well as environments in which individual cells reside.

Animals↗
PubMed1999

Nisoldipine improves the impaired erythrocyte deformability correlating with elevated intracellular free calcium-ion concentration and poor glycaemic control in NIDDM.

AIMS: To explore the mechanisms underlying the impaired erythrocyte deformability (RBC-df) in diabetic patients, the relationship between erythrocyte intracellular free calcium-ion concentration ([Ca2+]i) and RBC-df, and the effects of Ca2+-channel blocker on [Ca2+]i and RBC-df were evaluated. METHODS: Forty-eight patients with NIDDM and 24 control subjects were enrolled in this study. [Ca2+]i was determined using fura-2, and RBC-df by filtration method expressed as Deformability Index (DI). Erythrocytes were treated with nisoldipine to evaluate the effects of a Ca2+-channel blocker. RESULTS: [Ca2+]i was significantly higher (82.6 (78.0-87.2) vs 76.6 (74.3-81.2) nmol lRBC-1, P<0.001), and DI was significantly lower (0. 14 (0.09-0.28) vs 0.22 (0.16-0.28), P<0.01) in NIDDM than in controls. There was a significant correlation between HbA1c and [Ca2+]i (r=0.38, P<0.01), between HbA1c and DI (r=-0.51, P<0.01), and between [Ca2+]i and DI (r=-0.42, P<0.01). Stepwise multiple regression analysis revealed HbA1c and [Ca2+]i as independent determinants for the impaired RBC-df. Nisoldipine treatment in vitro significantly decreased [Ca2+]i, and significantly improved RBC-df. CONCLUSIONS: These data indicate that the impaired RBC-df in NIDDM may at least partly be attributed to the elevated [Ca2+]i and poor glycaemic control. In addition, favorable effects of a Ca2+-channel blocker on both [Ca2+]i and RBC-df have been demonstrated.

Adult↗
PubMed1999

Comparative study of assays for prostate-specific antigen molecular forms.

BACKGROUND: The detection of prostate-specific antigen (PSA) molecular forms such as free PSA and PSA-ACT and the use of PSA molecular ratios, especially the percentage of free to total PSA, have been reported to improve the diagnostic accuracy of prostate cancer in the patients with slightly elevated serum PSA values. However, the correlation among the values of serum free PSA or PSA-ACT obtained in various assays remains unclear. METHODS: Serum free PSA and PSA-ACT values were detected with the following assays: Hybritech, DPC, EIKEN, Abbott, Roche and Can-Ag for free PSA and Dainippon, Chugai, EIKEN and Bayer for PSA-ACT. The data obtained with each assay were compared with Hybritech (free PSA) and Dainippon (PSA-ACT) as standards. RESULTS: The free PSA data obtained with the Hybritech, EIKEN, Abbott and Can-Ag kits were similar. The values obtained with the DPC and Roche kits showed a linear regression of y = ax + b with those obtained with the Hybritech, with a b value of zero and an a value of 1.20 and 1.57, respectively. The serum PSA-ACT values detected with the Dainippon and Chugai kits were identical. The equation for converting the data obtained with the EIKEN kits to the Dainippon value was 0.7636 x (EIKEN) + 0.1381. CONCLUSIONS: Serum free PSA and PSA-ACT values obtained with various assays were not necessarily the same. Some kits for the assay of free PSA and PSA-ACT gave the same serum values. The free PSA values obtained with the other kits could be converted using appropriate equations. The gamma-Sm values showed wide variations and were not considered suitable as a measurement of free PSA.

Humans↗
PubMed1999

[A case of spontaneous pyeloduodenal fistula].

A 61-year-old woman visited our hospital complaining of right flank pain and fever. The radiograph demonstrated multiple renal calculi. Radio renography showed no uptake in the right kidney. Therefore, we diagnosed her with pyonephrosis, and recommended open nephrectomy. However, she selected the conservative treatment with extra corporeal shockwave lithotripsy (ESWL). In spite of disappearance of multiple calculi, pyuria continued for 3 months after ESWL. Retrograde pyelography showed a fistula from the right pelvis into the duodenum. The patient was successfully treated by nephrectomy and duodeno-fistelectomy.

Duodenal Diseases↗
PubMed1999

[Bacillus Calmette-Guerin intravesical instillation treatment for carcinoma in situ of the bladder. Gifu BCG Instillation Therapy Research Group].

We performed a retrospective long-term study to evaluate the efficacy of intravesical instillation of Tokyo 172 strain Bacillus Calmette-Guerin (BCG) on carcinoma in situ (CIS) of the bladder. Between 1989 and 1998, 42 patients with CIS of bladder underwent intravesical instillation of BCG. In the follow-up period from 6 to 116 months (mean: 37.3 months), the efficacy rate of intravesical BCG instillation for CIS of the bladder was 81.0%. Two patients died from the bladder cancer. The non-recurrence rate in patients with grade 2 carcinoma (19 cases) was not significantly different from that in those with grade 3 carcinoma (23 cases). However, the recurrence rate in patients with secondary CIS (15 cases) was significantly higher than in those with primary CIS (27 cases). The recurrence of CIS was observed in 7 of 42 cases. In 6 of 7 patients, CIS recurred within one year after treatment. Total cystectomy was performed in 10 of 42 patients, and pathological findings of muscle layer invasion were detected in 8 patients. Although side effects occurred in 33 patients (77.5%), no clinically significant side effects were observed. Our results suggest that intravesical BCG therapy may be useful for the treatment of CIS of the bladder.

Adjuvants, Immunologic↗
PubMed1999

[Pheochromocytoma of the urinary bladder: a case report].

A 49-year-old man was hospitalized with the chief complaint of coagulation in urine. The patient was not hypertensive. Cystoscopic examination showed a submucosal tumor in the left lateral wall of the bladder. A transurethral sonogram revealed a low echoic nodule. Transurethral resection of the tumor in the urinary bladder was performed. The histopathological diagnosis indicated pheochromocytoma. Blood pressure was stable. After operation, the patient's course was uneventful, and there has been no recurrence for one year after surgery. This patient is the 52nd patient with pheochromocytoma of the urinary bladder reported in the Japanese literature.

Follow-Up Studies↗
PubMed1998

Morphological changes of epithelial rests of Malassez in rat molars induced by local administration of N-methylnitrosourea.

The objective was to examine the possibility that epithelial rests of Malassez can give origin to odontogenic tumours. A mixture of N-methylnitrosourea (MNU) and alginate impression material for dental use was injected onto the periosteum of the buccal side of the left mandible of 5-week-old, male Wistar rats (300 mg/kg body wt). The mixture was left at the site for several months. The rats were killed 1, 3, 5, and 8 months after the injection. After 5 and 8 months, the epithelial rests of Malassez in the cervical and bifurcational regions of the first, second, and third left mandibular molars were significantly enlarged and the alveolar bone around the lesion was resorbed by multinucleated cells in all rats. The epithelial masses were characterized by enamel organ-like structures, deposition of eosinophilic amorphous material, duct-like structures, and squamous metaplasia. In addition to these masses in the molar regions, odontogenic tumours were induced in the incisal region and carcinomas and sarcomas in the buccal region, knee, bladder, and skin. Local administration of a mixture of MNU and alginate impression material can induce odontogenic tumours from the epithelial rests of Malassez at high incidence.

Alginates↗