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O Yamamoto

Publications and source records attributed to O Yamamoto.

At least 109 records · Page 6Linked to original sources
PubMed1993

A unique case of apocrine carcinoma on the male pubic skin: histopathologic and ultrastructural observations.

We report a case of cutaneous adenocarcinoma on the pubic region of a 56-year-old male. The exophytic tumor showed solid, ductal, and glandular patterns with decapitation secretion and mucinous carcinoma-like nests. Despite the exophytic nature of the lesion, an invasive growth pattern into the deep dermis and subcutaneous fat was seen. An additional characteristic of this tumor was the presence of Paget's phenomenon. From these findings, we conclude that this tumor is an apocrine adenocarcinoma having an unusual clinical appearance and unique histopathological features which have some similarities to apocrine carcinoma of the breast and some to syringocystadenoma papilliferum and nipple adenomatosis.

Adenocarcinoma↗
PubMed1993

Formation of 2,5-diamino-4-hydroxy-6-(2'-deoxyribosyl)-formamidopyrimidine from 2'-deoxyguanosine in aqueous solution irradiated with 60Co gamma-rays.

2'-Deoxyguanosine in aqueous solution (5 x 10(-4) mol/dm3) was irradiated with 60Co gamma-rays under N2O. Products were separated by gel chromatography (Cellulofine GC-15-m) and high performance liquid chromatography (Inertsil ODS-2). 2-Amino-4-hydroxy-5-formamido-6-(2'-deoxyribosyl)-aminopyrimidine was one of the main radiolytic products. The formation of 2,5-diamino-4- hydroxy-6-(2'-deoxyribosyl)-formamidopyrimidine was detected, this compound being verified by measuring its ultraviolet absorption spectrum and analyzing its trimethylsilylated derivative by gas chromato-mass spectrometry. Its yield in terms of 2-amino-4-hydroxy-5-formamido-6-(2'-deoxyribosyl)- aminopyrimidine was 1:3.

Chromatography, Gel↗
PubMed1993

[New surgical strategy for secondary hyperparathyroidism].

Extopic parathyroid glands and rudimentary glands which are not detected during initial parathyroidectomy may develop hyperplasia in the future, causing recurrence of hyperthyroidism. We have devised an improved surgical strategy to prevent the recurrence of hyperparathyroidism. The strategy is to dissect all central lymph nodes and fatty tissue according to the procedure of the dissection of thyroid cancer. The upper level of the dissection area is the upper edge of the thyroid cartilage and the lateral level of the dissection includes the lateral edge of the bilateral carotid sheath. Bilateral transcervical thymectomy is always included in this strategy. Upon confirming that more than 4 glands have been removed by intraoperative stamp cytology, total parathyroidectomy is terminated and 80 mg of glands is autotransplanted to the muscle of one forearm. We have performed this operation on 30 patients since 1987. More than 4 glands could be extirpated in every case, and supernumerary glands were detected in 6 cases (7 glands in 1 case and 5 glands in 4 cases). We have had no operative side effects in this series of 30 patients, and we have not experienced any persistent or recurrent hyperparathyroidism after any of these operations.

Adult↗
PubMed1993

[Transcatheter arterial chemoembolization to hepatic metastases from colorectal cancer].

Response of transcatheter arterial chemoembolization (TAE) and transcatheter arterial infusion chemotherapy to hepatic metastases was reported in 25 cases of colorectal cancer. The severity of liver metastases was H1 in 12 cases, H2 in 9 cases, and H3 in 4 cases. Liver metastases were found during surgery in 12 of these patients, and 13 showed metastases or recurrence in the liver after resections of primary lesions. Catheters were inserted selectively to the proper hepatic artery by Seldinger's method, followed by injection of embolizing agents (gelfoam particles of Lipiodol) with adriamycin or 5-FU + leucovorin in most cases. Response was assessed by blood CEA levels, diagnostic imaging, and period of survival. In 5 cases in whom liver resections were performed following TAE, response was assessed by histopathological findings of the resected specimens. Two patients showed partial response (PR), 12 no change (NC) and 11 progressive disease (PD) by diagnostic imaging. Blood CEA levels fell to less than 50% of pre-treatment levels in 26% of cases. Histological changes by TAE were confirmed in 4 of 5 cases after liver resections, but viable cancer cells were observed in all cases. A case of mucinous cancer showed no change histologically. As the other case of mucinous cancer showed PD by diagnostic imaging, TAE was not suggested to be suitable to treat cases of mucinous cancer. More improvements in the dosage, drugs and times of treatment were suggested to yield a better response rate in TAE therapy for liver metastases from colorectal cancer.

Adult↗
PubMed1992

Morphological development of the rat fetal pancreas.

Rat fetal pancreata of days 12 to 19 of gestation and those of neonates were examined with light and electron microscopes. The pancreas arose from the primitive epithelium of the foregut as two primordia (dorsal and ventral pancreatic primordia) of epithelial cell nests surrounded with abundant fetal mesenchymal tissue between days 11 and 12. Primitive pancreatic islets, which mainly consisted of the endocrine cells with A cell type secretory granules, also appeared in the primordia at this age. The epithelial cell nests elongated gradually and had a branching cord-like arrangement. Two pancreatic primordia fused together on day 15, and an apparent ductular structure was observed on days 15 to 17. An acinar configuration of exocrine cells with zymogen granules gradually formed between days 17, 18 and 19. After birth, the volume of pancreatic parenchyma markedly increased and that of mesenchymal tissue prominently decreased. Ultrastructurally, the pancreatic primordia in the early stage showed immature epithelial features with the surrounding basement membrane and inconspicuous intercellular junctions. This might imply a plasticity in cellular differentiation of protodifferentiated pancreatic epithelial cells toward a ductular structure of immature exocrine pancreas which appeared later. In addition to the basement membrane, abundant fetal mesenchymal tissue was considered to play a possible role in the early morphogenesis in pancreatic development.

Animals↗
PubMed1992

Antitumor effect of triphenylethylene derivative (TAT-59) against human breast carcinoma xenografts in nude mice.

The antitumor activity of a newly synthesized triphenylethylene derivative [(E)-4-[1-[4-[2-(dimethylamino)ethoxy-phenyl]-2-(4-isopropyl)phenyl-1- butenyl] phenyl monophosphate] (TAT-59) was investigated against human breast carcinoma xenografts in nude mice with reference to the changes of hormone receptors. Five strains (MCF-7, Br-10, R-27, ZR-75-1, and T-61) used for the experiments possessed cytosol estrogen receptor (ER), and their growth was estradiol dependent. Five mg of TAT-59 and tamoxifen citrate (TAM) per kg were administered p.o. daily except Sunday. TAT-59 showed a positive antitumor effect against MCF-7 and R-27, whereas TAM was effective on MCF-7, and their adverse effects detected by mortality rate, body weight loss, and spleen weight loss were similar to each other. The reduction of ER and production of progesterone receptor (PgR) after the treatment with TAT-59 were more potent than after TAM, suggesting that TAT-59 exerts its antitumor effect through binding to ER. These findings suggest that TAT-59 might merit use in clinical trials with breast cancers.

Animals↗
PubMed1992

A histopathological and ultrastructural study of eccrine porocarcinoma with special reference to its subtypes.

Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononuclear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.

Adenoma, Sweat Gland↗
PubMed1992

Iron(II) sulphate (Fricke solution) oxidation yields for 8.9 and 13.6 keV X-rays from synchrotron radiation.

The oxidation yields (G) for 8.86 and 13.55 keV X-rays produced by synchrotron radiation were measured using an iron(II) sulphate (Fricke) solution. Monoenergetic X-rays were produced using a silicon crystal monochromator. The X-rays were absorbed in 0.4 M sulphuric acid-iron(II) sulphate solution and FeIII ion yields were measured and corrected for escape fractions resulting from scattering using Monte Carlo calculations. Doses in the solution were determined using a thin window, parallel plate chamber calibrated against a primary standard free-air chamber at the Electrotechnical Laboratory (Osaka, Japan). Yields (G) of 1.50 +/- 0.06 and 1.43 +/- 0.06 mumol J-1 were obtained for 8.86 and 13.55 keV X-rays respectively.

Oxidation-Reduction↗
PubMed1992

Sweat gland carcinoma with mucinous and infiltrating duct-like patterns.

We report a rare case of mucinous carcinoma of the skin with mammary infiltrating carcinoma-like patterns. An 82-year-old Japanese male had a gourd-shaped tumor on his scalp. Histopathologically, the posterior portion of the tumor showed small lobules of cuboidal tumor cells with no atypia floating in mucinous lakes. In the anterior portion, there were solid lobules, cords, and strands of anaplastic tumor cells infiltrating into the surrounding stroma. Enzyme- and immunohistochemistry and electron microscopy confirmed the eccrine origin of this tumor. It is suggested that mucinous carcinoma of the skin can occur in association with diverse histological patterns, analogous to mucinous carcinoma of the breast.

Acid Phosphatase↗
PubMed1992

An aged patient with Henoch-Schönlein purpura nephritis: a case report and review of the literature.

A 63-year-old patient with Henoch-Schönlein purpura (HSP) nephritis showed progressive proteinuria. Purpura was observed in the extremities as well as in the trunk without any preceding upper respiratory tract infections or drugs, and it disappeared after corticosteroid therapy although mild proteinuria continued throughout the therapy. Renal biopsy specimens showed mesangial IgA deposits in the glomeruli, but no IgA deposits were observed in the dermal vessels or in the intrarenal extraglomerular capillaries. Progressive proteinuria was improved with 37.5 mg/day of captopril. Severity of HSP nephritis in middle-aged to aged patients in the literature was reviewed. It was suggested that careful observation is required in aged patients with HSP nephritis.

Aged↗
PubMed1992

An ultrastructural comparison of sinusoids in hepatocellular carcinoma, adenomatous hyperplasia, and fetal liver.

Transmission and scanning electron microscopic examinations were performed to evaluate the fine-structural differences in sinusoids of hepatocellular carcinoma, adenomatous hyperplasia of the liver, and fetal livers. In cancerous sinusoids, thickened endothelial cells with loss of sieve plates were conspicuous features. In the sinusoids of adenomatous hyperplasia, scanning electron microscopy showed apparent sieve plates, and basement membrane formation (capillarization) was less conspicuous than in carcinoma. In fetal livers, occasional large gaps as well as small fenestrations in the endothelium were noted. Basement membrane materials were not seen. It was concluded that the sinusoids of hepatocellular carcinoma lost the fine-structural nature of normal sinusoids and showed much more prominent capillarizations than the sinusoids of adenomatous hyperplasia, and that the fine structures of cancerous sinusoids were also different from those of the sinusoids in fetal livers.

Adenoma↗
PubMed1992

[A case of advanced breast cancer responding to low-dose 5'-DFUR].

A 69-year-old female patient with locally advanced breast cancer with multiple bone metastases (T4cN2-M1) was treated with 5'-DFUR after failure of tamoxifen treatment. The 5'-DFUR dose was limited to 600 mg per day, half the usual dose, because of its gastroenterological side effects. The primary tumor and metastatic axillary lymph nodes regressed three months after the start of treatment, and the complete remission of lesions was obtained in 16 months. Reduction of bone metastasis was confirmed by the disappearance of osteolytic lesion in the skull roentgenogram and the decrease of abnormal accumulation on the bone scintigram. Serum levels of CEA and ST-439 markedly reduced during the treatment as the disease regressed.

Aged↗
PubMed1992

[Intra-arterial chemotherapy of local recurrence and non-curative case of colorectal cancer].

Twelve colorectal cancer patients, including 9 with local recurrent cancer and 3 with remnant cancer after surgery, were treated with intraarterial chemotherapy. Three cases were treated with MMC injection alone, 1 case with MMC combined with irradiation (MMC-R) and 8 cases with ADM combined with irradiation (ADM-R). In 7 evaluable patients, the response rate was 28.6% with 1 CR case, 1 PR case and 5 NC cases. The 2 cases treated with ADM-R were successful. Six of 8 patients treated with ADM-R survived more than 1 year, while all 4 patients treated with MMC or MMC-R died within 8 months. The cumulative survival rate after ADM-R treatment was 44% at 24 months. It is suggested that the combination of intra-arterial chemotherapy and radiation therapy is an effective treatment for local recurrence and non-curative cases of colorectal cancer.

Chemotherapy, Adjuvant↗
PubMed1992

[A case of dermatomyositis associated with thymic abnormalities].

A case of dermatomyositis (DM) associated with thymic cyst with lymphoid follicle formations has been reported. A 57-year-old man developed polyarthralgia, muscle weakness, heliotrope rash and Gottron's sign. Laboratory findings showed elevated values of creatine-phosphokinase, aldolase and transaminase. He was diagnosed as DM and was treated with prednisolone 50 mg/day. Muscle weakness was improved immediately, although rash persisted unchangeably. He was examined for coexistence of malignant tumor which had been reported frequently as associated with DM. Enlargement of thymus was found by computer tomography and then thymectomy was performed. In his thymus, lymphoid follicle formations, which are as often encountered in other autoimmune diseases, were found. So far, the beneficial effect of thymectomy on the improvement of immunological abnormalities not only in patients with myasthenia gravis but also in patients with other autoimmune diseases has been recognized. In this case, intractable rash in DM improved after thymectomy. Further study needs to clarify the relationships between DM and thymic abnormalities.

Dermatomyositis↗
PubMed1991

cDNA clones of Japanese hepatitis C virus genomes derived from a single patient show sequence heterogeneity.

Twelve cDNA clones of Japanese hepatitis C virus (HCV) have been isolated from liver tissue of a single non-A, non-B hepatitis patient. These clones represented the non-structural domains of HCV. The degree of substitution in the nucleotide sequences and deduced amino acid sequences between these clones was 9.5 and 7.7%, respectively. This high level of substitution suggested that repeated infections of different HCVs may have occurred in the patient.

Amino Acid Sequence↗
PubMed1991

Control of specific absorption rate distribution using capacitive electrodes and inductive aperture-type applicators: implications for radiofrequency hyperthermia.

A method of controlling the specific absorption rate (SAR) distribution in radiofrequency hyperthermia is proposed. The superposition of the current density associated with capacitively coupled electrodes and that associated with H-field coupled inductive aperture-type applicators modifies the actual current distribution in the heating material. Using a two-dimensional finite element method, we have shown that "focusing" is possible such that the SAR at the center of a phantom can be adjusted to be approximately twice that in superficial regions, even though the wavelength is considerably greater than the dimensions of the phantom.

Electric Conductivity↗
PubMed1991

Medusa head-like granules in squamous cell carcinoma with differentiation toward a hair follicle structure.

A case of squamous cell carcinoma (SCC) with regional lymph node metastasis in a 69-year-old Japanese man is reported. The tumor was characterized by the proliferation of peripheral basaloid, inner squamoid, and glycogen-rich cells, the presence of trichilemmal keratinization, and the presence of ladder-like, membrane-coating granules. These findings suggested that this tumor differentiates toward a hair-follicle structure. The most interesting feature of this tumor was the presence of medusa head-like granules in the cytoplasm of the clear squamoid cells adjacent to the keratinized cells. We have been unable to find any other studies of these granules in squamous cell carcinoma.

Aged↗