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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 595 records · Page 33Linked to original sources
PubMed1989

Carcinoma arising in fibroadenoma of the breast--a case report and review of the literature.

A 47 year old woman with two isolated lumps in her right breast underwent an excisional biopsy and the histological findings of both lesions revealed fibroadenoma with an in situ lobular carcinoma. Patey's modified radical mastectomy was performed after which careful follow-up was continued. To date, a total 161 cases of carcinoma arising in a fibroadenoma have been reported in the world literature and a review of these literature is given following the case report.

Adenofibroma↗
PubMed1989

Corrosive gastritis mimicking linitis plastica carcinoma.

A 59-year-old female with depressive tendencies was admitted suffering from hematemesis and abdominal pain, two hours after ingestion of an unknown amount of toilet bowl cleaner (hydrochloric acid, pH 1.0). A barium study 24 days after ingestion revealed rigid narrowing and granulation of the entire stomach. The esophagus and duodenum were normal. The radiographic results were similar to those obtained for linitis plastica carcinoma of the stomach, but biopsy specimens of the stomach revealed no cancer cells. A total gastrectomy was performed about two months after ingestion to relieve the persistent feeling of nausea. Specimens revealed a rigid and thickening lining and a denuded mucosal surface of the stomach. The cut surface of the specimen showed a remarkable fibrous thickening of the submucosal layer. Microscopic examination failed to reveal a normal mucosal layer except in a narrow area of the fornix, and remarkable fibrosis of the submucosal lining was noted. No cancer cells were found. Corrosive gastritis has a linitis plastica appearance with a predilection for the antrum. Radiological examination revealed the very rare manifestation of a rigid narrowing of the whole stomach mimicking linitis plastica type cancer.

Adenocarcinoma, Scirrhous↗
PubMed1989

Corrosion properties of soldered joints. Part I: Electrochemical action of dental solder and dental nickel-chromium alloy.

The corrosion properties of contact between six Ni-Cr alloys and two dental solders were evaluated. Ni-Cr alloys with low Cr content coupled with silver solder induced continuous galvanic current, whereas Ni-Cr alloys with high Cr and some Mo content coupled with silver or gold solder induced galvanic current for a short time. Six Ni-Cr alloys were divided into two groups according to the dissolution of Ni, one with low resistance and the other with high resistance. The initial equilibrium was induced between high resistance Ni-Cr alloys and both solders by less current density, which implies a smaller degree of corrosive current than that in low-resistance alloys. Corrosion was observed in the silver solder coupled with high-resistance Ni-Cr alloy, but was not found in the gold solder coupled with both alloys. In soldering Ni-Cr alloy, it is better to use a gold solder and a high-resistance Ni-Cr alloy for corrosion resistance.

Chromium↗
PubMed1989

Evaluation of the methods for dislodging the impression tray affecting the dimensional accuracy of the abutments in a complete dental arch cast.

The dimensional accuracy of dies was evaluated in complete dental arch casts made by three different methods of dislodging the impression tray. By one method, the impression tray was dislodged parallel to the long axis of the abutment and by the other two the trays were inclined with the fulcrum at either the posterior or anterior region of the complete dental arch. The dimensional changes of the molar-die were significantly affected by the dislodging method in the inclined way but not those of the incisor-die. The anteriorly inclined method showed fewer dimensional changes than the posteriorly inclined method. On the other hand, the dimensional changes of the incisor-die were not significant by any dislodging method, but were observed when some impression material was used. If the impression tray is removed by the inclined way, the fulcrum should be chosen at a region remote from the abutment instead of at the proximal region.

Calcium Sulfate↗
PubMed1989

Clinical study of primary carcinoma of the fallopian tube: experience with 15 cases.

Between 1950 and 1986, fifteen cases of primary carcinoma of the fallopian tube were diagnosed and treated at the Cancer Institute Hospital, Tokyo. These cases constituted 0.14% of the total number of gynecologic malignancies at the hospital during that period. The average age of the 15 patients was 55.7 years. The most frequent symptom was atypical genital bleeding, seen in 12 cases (80%). Massive watery discharge was seen in 4 cases (27%). In preoperative cytologic examination, 6 cases (40%) were positive for cancer. All cases underwent operation as therapy. Postoperative irradiation, adjuvant chemotherapy, and/or second- or third-look operations were also performed. Histopathologically, all materials were found to be adenocarcinoma. Four cases were well differentiated, eight were moderately differentiated, and three were poorly differentiated. As for the prognosis, 7 patients were followed more than 5 years postoperatively. The 5-year survival rate was 57% (4/7). In stage I cancers, the 5-year survival rate was 80% (4/5). The prognosis of stage I cancer patients was estimated to be rather good.

Adenocarcinoma↗
PubMed1989

Use of angio computed tomography to evaluate extent of endometrial carcinoma.

Patients with endometrial carcinoma underwent angio computed tomography (CT) prior to surgery to evaluate the extent of the carcinoma. The subjects of the study were 87 patients operated on at the Cancer Institute Hospital during the period 1983 to 1986. After preoperative bilateral internal iliac angiography, angio CT was performed using the already inserted catheters. Although the intact uterine wall was enhanced by the angio CT, the cancerous lesion was not, which permitted easy recognition of the cancerous lesion as a low-density area. To evaluate the degree of myometrial invasion, the minimal thickness of intact uterine wall was measured in the CT image, and was compared later with findings from the operative materials. The comparison showed that for all the patients, the minimal thickness of the intact uterine wall as shown in the CT image was comparable to the actual minimal thickness of the operative materials. Because depth of myometrial invasion is known as an important prognostic factor, measurement of the minimal thickness of the intact uterine wall as shown in the CT image is useful as an objective prognostic factor. Angio CT facilitates recognition of myometrial invasion preoperatively.

Contrast Media↗
PubMed1989

Discriminative stimulus properties of the mixed agonist-antagonist pentazocine in the rat using two-choice discrete-trial avoidance paradigm.

The discriminative stimulus effects of pentazocine were evaluated in the rat trained to discriminate 3.0 mg/kg of pentazocine from vehicle in a two-choice discrete-trial avoidance paradigm. The rats used could discriminate 3.0 mg/kg of pentazocine from vehicle within 20 sessions after the start of discrimination training. The stimulus effects lasted 30 to 90 min and disappeared thereafter except for one rat in which the discriminative effects lasted 30 to 150 min. Pentazocine produced dose-dependent stimulus effects at 0.3 to 3.0 mg/kg doses. The stimulus effects of pentazocine were fully reversed by higher doses of naltrexone. Butorphanol, nalorphine, morphine, levorphanol, SKF 10,047, and methamphetamine generalized to pentazocine cue. However, ethylketocyclazocine, dextrorphan or pentobarbital did not produce stimulus effects in common with pentazocine. These results suggest that the discriminative stimulus effects of pentazocine (3.0 mg/kg) are mediated through an opioid but non-mu and nonspecific mechanism.

Animals↗
PubMed1989

Apocrine hidrocystoma--a report of five cases and review of the Japanese literature.

Five cases of apocrine hidrocystoma are reported. One is multiple and the others are solitary lesions. There are more than 60 cases reported in the Japanese literature. Apocrine hidrocystomas usually occur as a solitary lesion. Only two cases of multiple apocrine hidrocystoma have been described so far in Japan. We reviewed the literature and discussed the clinicopathologic nature of this tumor. Apocrine hidrocystomas are usually composed of a cystic cavity lined by columnar epithelium, showing apocrine type secretion. Peripheral to this, myoepithelial cells are usually seen; however, they were absent from all of the present cases. Change in hue of the tumor is another characteristic feature. About half of the reported Japanese cases exhibited distinctive coloration, variously light brown, red-brown, or bluish. In contrast, non-Japanese cases tended to have darker coloration.

Adult↗
PubMed1989

The subbasement membrane distribution of type IV collagen in normal human skin.

Samples of normal human skin were obtained from 48 sites in 26 subjects ranging in age from 2 to 85 years. The samples were examined by indirect immunofluorescence and immunoelectron microscopy using anti-human type IV collagen antibodies produced by immunizing rabbits with type IV collagen extracted from human placenta. Fluorescence was observed as granular or fine fibrous patterns, not only in the basement membrane at the dermo-epidermal junction, around the vessels, and the accessory organs of the skin, but also in the dermal regions in the vicinity of the basement membranes. This suggests the presence of type IV collagen in the dermis deep to the basement membrane. Ultrastructurally, the extrabasal lamina distribution of type IV collagen was noted as a partial distribution around the fibroblasts that existed close to the basal lamina. These findings are considered to be important in examining the function of this collagen in the dermis and the dynamics and metabolism of the basement membrane under normal and abnormal conditions.

Adolescent↗
PubMed1989

Farber's lipogranulomatosis in siblings: light and electron microscopic studies.

Two cases of Farber's lipogranulomatosis in siblings are reported. The clinical features included contractures of the limbs with swelling of the joints and subcutaneous nodules and erythematous infiltrated plaques. On histology there were many large foam cells in the dermis, and electron microscopy showed numerous large cells with round cytoplasmic lamellar and microtubular bodies.

Child, Preschool↗
PubMed1989

Diffuse pleural rhabdomyosarcoma with persistent pleural effusion.

A unique case of embryonal rhabdomyosarcoma arising at the left pleura of a 7-year-old Japanese girl is reported. The present case was characterized by persistent pleural effusion, and the malignant cells incidentally found in it were the first diagnostic clue. The tumor showed a rare growth pattern involving diffuse thickening of the parietal pleura. Biopsy of the thickened parietal pleura upon thoracotomy revealed embryonal rhabdomyosarcoma largely composed of immature mesenchymal cells. Immunohistochemical demonstration of creatinine phosphokinase-MM was most helpful among several types of immunostain for the histopathological diagnosis. Ultrastructurally, thin filaments with primitive Z bands could be seen in some tumor cells. Intensive clinical examination revealed only diffuse thickening of the parietal pleura, which was reduced by chemotherapy. This is the first documented case of rhabdomyosarcoma arising at the pleura. Previous reports of rhabdomyosarcoma arising at unusual sites are reviewed and the histogenesis of this tumor is briefly discussed.

Child↗
PubMed1989

Congenital cytomegalovirus infection associated with fetal ascites and intrahepatic calcifications.

A fetus at 20 weeks' gestation was shown by ultrasonography to have ascites and intrahepatic calcifications. We aspirated the fetal ascites at 29 and 30 weeks' gestation to decompress the fetal lungs due to the progression of the ascites and the concomitant compression in the fetal lungs. The newborn had neither hypoplasia of the lungs nor any respiratory complication, though congenital cytomegalovirus infection was present. This is the first report of such congenital cytomegalovirus infection associated with fetal ascites and intrahepatic calcifications. Careful monitoring and early intervention is necessary for a good prognosis.

Adult↗
PubMed1989

Pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1, 4-diazepin-1-yl)-1H-benzimidazole difumarate (KG-2413) after oral administration: interspecies differences in rats, guinea pigs and dogs.

The pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1, 4-diazepin-1-yl)-1H-benzimidazole difumarate (KG-2413) after oral administration were studied in rats, guinea pigs and dogs. Maximum plasma level (Cmax) appeared at 23, 32 and 51 min after dosing in rats, guinea pigs and dogs, respectively. Plasma half-lives of the terminal phase were comparable to those after intravenous administration in each animal species. Pronounced interspecies differences were observed in the Cmax/dose and area under the plasma concentration-time curve (AUC)/dose, namely, these values were high in guinea pigs and low in rats and dogs. The extents of bioavailability were 0.036 in rats (20 mg/kg), 0.50 in guinea pigs (2 mg/kg) and 0.052 in dogs (2 mg/kg). These variations in the pharmacokinetic parameters in the animals were assumed to be mostly due to the species difference in the hepatic intrinsic clearance.

Administration, Oral↗
PubMed1989

Interspecies differences in pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1,4-diazepin-1-yl) benzimidazole difumarate (KG-2413) after intravenous administration to rats, guinea pigs and dogs.

Interspecies differences in the pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1,4-diazepin-1-yl)benzimid azole difumarate (KG-2413) after intravenous administration were investigated in rats, guinea pigs and dogs. The disappearance of unchanged KG-2413 base was described by biexponential curves in all three animal species. The areas under the plasma concentration-time curves (AUC) in rats, guinea pigs and dogs were 218, 421 and 369 ng.h/ml, respectively, at a dose of 2 mg/kg. The volume of distribution in rats was comparable to that in dogs, and was about three times greater than that in guinea pigs. This might be due to the difference in the unbound fractions of KG-2413 base in plasma (fu), that is, the values of fu in rats, dogs and guinea pigs were 0.607, 0.603 and 0.189, respectively. The first-order elimination rate constant from the central compartment (kcl) in dogs were smaller than those in rats and guinea pigs. Total body clearances (CLtot) of KG-2413 base in rats and guinea pigs were comparable to the hepatic blood flow rate (Q) of each animal. Assuming that KG-2413 base is only eliminated in the liver, relatively rapid metabolism of KG-2413 base occurred in the liver of rats and guinea pigs. In dogs, extrahepatic elimination was suggested because the value of CLtot seemed to be greater than that of Q.

Animals↗
PubMed1989

[Selective and sensitive determination of an antiallergic agent, emedastine difumarate (KG-2413), in human plasma by the radioreceptor assay combined with a high-performance liquid chromatography].

The selective and sensitive method for the determination of a new antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H-b enzimidazole difumarate (emedastine difumarate, KG-2413), in the human plasma has been developed. Emedastine was determined by the receptor assay after the separation from its metabolites by the use of high-performance liquid chromatography (HPLC). This combined method (HPLC-radioreceptor assay (RRA) method) allowed us the quantification only of 0.3 ng/ml of emedastine in the human plasma. The intra-assay coefficients of variation for the determination were below 12%. Furthermore, the total pharmacologically active metabolites, including unchanged emedastine, was determined by the extraction of the unconjugated metabolites in the human plasma with chloroform followed by the receptor assay (RRA method). The human plasma concentrations measured by the HPLC-RRA method were in good agreement with those by the RRA method. These results suggested that in human pharmacological activities occurred by unchanged emedastine itself.

Adult↗
PubMed1989

[Identification of the metabolites of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepine-1-yl)-1H- benzimidazole difumarate (KG-2413), in rats].

The urinary and biliary metabolites of a new antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepine-1-yl)-1H-b enzimidazole difumarate (KG-2413) in rats were identified by using a 14C-labelled drug and instrumental analyses, e.g., high performance liquid chromatography, gas chromatography (GC), 1H nuclear magnetic resonance, mass spectrometry (MS) and GC/MS. A slight amount of KG-2413 free base was detected only in the unconjugated fraction of urine. The main pathways of biotransformation of KG-2413 in rats were: (a) aromatic hydroxylation in the benzimidazole ring, (b) N-oxidation and N-demethylation in the 1,4-diazepine ring, (c) alpha-carbon oxidation (lactam formation) in the 1,4-diazepine ring (d) O-deethylation in the N-ethoxyethyl side chain. Regioselectivity was observed for aromatic hydroxylation, as only two of the four possible monohydroxylated metabolites could be detected. Furthermore, N-oxidation and lactam formation reactions were found to be regiospecific, that is, the former took place only at the position of 4-N atom and the latter at 5-C atom, respectively.

Animals↗
PubMed1989

[Cross-reactivities of active metabolites in the radioreceptor assay of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)- 1H-benzimidazole difumarate (KG-2413)].

A new antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H- benzimidazole difumarate (KG-2413), was orally administered to guinea pigs at a dose of 2 mg/kg. The drug levels in the plasma measured by the radioreceptor assay (RRA) method were significantly higher by 7% than those by the gas chromatographic (GC) method which was selective for the intact drug. Among the metabolites of KG-2413, 1-(2-ethoxyethyl)-2-(hexahydro-1H-1,4-diazepin-1-yl)- 1H-benzimidazole (desmethyl metabolite) and 1-(2-ethoxyethyl)-5-hydroxy-2-(hexahydro-4-methyl-1H-1,4-diazepin- 1-yl)-1H- benzimidazole (5-hydroxy metabolite) had relatively high cross-reactivities of 29% and 21%, respectively, on the RRA method. However, the 5-hydroxy metabolite was not extracted with benzene under strongly basic conditions on the extraction procedure carried out prior to the receptor assay. Therefore, it was suggested that the desmethyl metabolite might affect the RRA method. In order to determine the amount of the desmethyl metabolite in the plasma, a high-performance liquid chromatographic method was established to determine the dansyl derivative of the desmethyl metabolite. By using this method, it was found that the desmethyl metabolite corresponding to 21-32% of the intact drug was present in the plasma after oral administration of KG-2413 at a dose of 2 mg/kg. Taking account of the cross-reactivity (29%) and extraction ratio (83%) of the desmethyl metabolite, this active metabolite affects the RRA method to give 5.1-7.7% overestimation of the intact drug concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗