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Y Osamura

Publications and source records attributed to Y Osamura.

At least 19 recordsLinked to original sources
PubMed1997

The role of histamine in ethanol-induced gastric mucosal injury in the rat.

It has been suggested that changes in the micro circulatory system are related to the early production of acute gastric mucosal injury and inflammatory factors such as prostaglandins, histamine, etc., have been considered as contributing to the development of the injury. We assessed the permeability of the gastric mucosa in rats with ethanol-induced acute mucosal injury by measuring the leakage rate of 51chronium-ethylene-diamine-tetraacetic acid (51Cr-EDTA) into the gastric juice. Histamine concentrations in the gastric mucosa was measured by high performance liquid chromatography. The enterochromaffin-like (ECL) cell counts in the gastric mucosa was performed following histamine staining with an enzyme-labeled antibody, and the histamine released due to degranulation was observed. We also investigated the kinetics of endogenous histamine in the gastric mucosa. Five minutes after the administration of ethanol, an increase in permeability, an increase in histamine concentration, and a decrease in ECL cell count were found in the gastric mucosa. These results suggest that endogenous histamine in the gastric mucosa is closely related to the early development of acute gastric mucosal injury.

Animals↗
PubMed1996

Myofibroblastoma of the breast: report of a case.

We report herein the case of a 36-year-old woman in whom a breast mass was diagnosed histologically and immunohistochemically as myofibroblastoma (MFB). The patient initially presented with a breast mass measuring 1.0 x 1.5 cm which was demonstrated by mammography as a well-circumscribed, round tumor with two coarse calcifications. On ultrasonography, the tumor showed slight shadowy internal echoes. Histological examination of an excisional biopsy specimen demonstrated a tumor consisting of spindle-shaped cells and broad bands of hyalinized collagen with cartilaginous and osseous components, but no epithelial components were observed. Immunohistochemically, the tumor cells were diffusely positive for alpha smooth muscle actin, and a diagnosis of MFB was made. A wide excision of the breast was performed as a secondary procedure, and the patient is well and free from recurrence 1 year after her operation. We present this case to stress the need for breast surgeons to be aware of the existence of MFB when considering the differential diagnosis of stromal lesions of the breast to avoid performing unnecessarily extensive procedures.

Adult↗
PubMed1996

A case of pituitary somatotroph adenoma with concomitant secretion of growth hormone, prolactin, and adrenocorticotropic hormone--an adenoma derived from primordial stem cell, studied by immunohistochemistry, in situ hybridization, and cell culture.

Somatotroph adenomas often secrete prolactin (PRL) besides growth hormone (GH) and are sometimes immunostained for other anterior pituitary hormones or their subunits, such as thyroid-stimulating hormone (TSH) beta-subunit and glycoprotein hormone alpha-subunit (alpha SU). However, somatotroph adenomas showing hypersecretion of adrenocorticotropic hormone (ACTH) are extremely rare. There have been, to our knowledge, only five published reports on somatotroph adenomas accompanied by excessive ACTH secretion. Here we report a case of intracavernously invading somatotroph macro-adenoma with high serum GH, PRL, and ACTH levels. We examined the case using immunohistochemistry (IHC), in situ hybridization (ISH), and cell culture, and confirmed GH, PRL, and ACTH, as well as alpha SU, production, and the expression of Pit-1 protein by the adenoma, which is known as a transcriptional factor for GH, PRL, and TSH, not for ACTH. Therefore, the presence of unknown transcriptional factor other than Pit-1, common to GH, PRL, and ACTH, may be speculated to be expressed in this adenoma. In our previous study, we had found plurihormonal mRNA expression, especially for ACTH, the beta-subunit of follicle-stimulating hormone and luteinizing hormone in some somatotroph adenomas, using non-radio-isotopic ISH, and suggested that these adenomas might be derived from plurihormonal primordial stem cells. Our present case is significant from the viewpoint of histogenesis of pituitary adenomas, because it further supports the cell origin of somatotroph adenomas from plurihormonal primordial stem cells, and moreover it suggests the presence of unknown transcriptional factor other than Pit-1, common to GH, PRL, and ACTH.

Adenoma↗
PubMed1996

Cyclic Cushing's disease in long-term remission with a daily low dose of bromocriptine.

A 56-year-old male patient with cyclic Cushing's disease remained in a state of remission for more than one year with a relatively low dose of bromocriptine (2.5-3.75 mg/day). It has been reported that bromocriptine treatment for cyclic Cushing's disease induces only a transient remission; in the most effective cases, a relatively high dose (40 mg/day) was necessary. In the hypercortisolemic state, plasma adrenocorticotropic hormone (ACTH) and serum cortisol were not suppressed by dexamethasone and did not respond to corticotropin-releasing factor (CRF). An antehypophysectomy was not effective, even though the resected tissue contained ACTH-positive microadenomas. The present observations thus indicate the effectiveness of bromocriptine for some patients with this rare disorder.

Adenoma↗
PubMed1996

[Intermediate filaments].

The antibodies for intermediate filaments, including keratin, vimentin, desmin, GFAP and neurofilaments, have been much useful in routinely-processed immunohistochemical study for identifying characteristics of tumor cells or making the definite diagnosis. In general, when neoplastic transformation has taken place, the affected cells would reveal to some extent alterated immunolocalization of intermediate filaments in the cytoplasm. Whether the tumor cells are of epithelial or non-epithelial origin is significant from diagnostic points of view when utilizing those intermediate filaments as tumor markers. But there are many "exceptional" cases of epithelial tumors with expression of vimentin, or those of non-epithelial tumors with expression of keratin, indicating some "variants". Immunohistochemical application of the intermediate filaments is indispensable not only as "a diagnostic tool for surgical pathologists", but also a method for analyzing relationship between morphological changes and functional aspects of the tumor cells.

Humans↗
PubMed1996

Endoscopic screening for esophageal cancer in 788 patients with head and neck cancers.

Esophageal cancer has a poor prognosis because it is difficult to detect in its early stages and, even if an operation is possible, the postoperative quality of life is much impaired. An early diagnosis can lead to a good prognosis and enables treatment by endoscopic mucosal resection (EEMR), contributing to a postoperative good quality of life. As head and neck cancers are known to have a high risk of concomitant esophageal cancer, endoscopic screening with iodine staining was performed on 788 patients with head and neck cancers. Among them, 93 cases of esophageal cancers (11.8%) and 23 cases of gastric cancers (2.9%) were detected. Seventy-two cases (77.4%) of the 93 esophageal cancers were superficial cancers limited to the submucosal layer. Twenty cases, treated by EEMR, had a good postoperative course without local recurrence. We suggest that endoscopic screening for esophageal cancer should be performed on all patients with head and neck cancers, because it allows early detection and a good prognosis, and the treatment can be completed by endoscopic maneuver.

Aged↗
PubMed1995

Immunohistochemical localization of carcinoembryonic antigen as a predictor of lymph node status in submucosa-invasive colorectal carcinoma.

PURPOSE: Submucosa-invasive colorectal carcinoma is a colorectal carcinoma extending only into the submucosal layer. To clarify the metastatic potential of submucosa-invasive colorectal carcinoma, we studied the relationship between the immunohistochemical staining pattern of carcinoembryonic antigen (CEA) and that of lymphatic invasion/lymph node metastasis. METHODS: We investigated 49 submucosa-invasive colorectal carcinomas resected surgically or endoscopically. CEA distribution patterns of the neoplastic tissues were divided into three patterns: Pattern 1 = luminal type; Pattern 2 = apical cytoplasmic type; and Pattern 3 = diffuse cytoplasmic type. We also observed the submucosal stromal staining of CEA. RESULTS: Lymphatic invasion and lymph node metastasis were found in 48.8 percent (21/43) and 11.6 percent (5/43) of the Pattern 2/Pattern 3 cases, whereas these were seen in none (0/6) of Pattern 1 cases. Lymphatic invasion and lymph node metastasis were found in 63.3 percent (19/30) (chi-squared = 21.94; P < 0.001) and 16.7 percent (5/30) of the positive stromal CEA cases, whereas these were seen in 10.5 percent (2/19) and none (0/14) of the negative stromal CEA cases, respectively. CONCLUSION: Pattern 2/Pattern 3 and stromal CEA can be predictors of the lymph node metastasis with 11.6 percent and 16.7 percent risks.

Adult↗
PubMed1995

Lymphocytic hypophysitis: case report.

We report a rare case of lymphocytic hypophysitis in a 52-year-old man who presented with a combination of hypopituitarism and diabetes insipidus. Magnetic resonance imaging with a contrast medium revealed an expanding sellar mass and thickening of the pituitary stalk with homogeneous enhancement. These findings may be useful in differentiating lymphocytic hypophysitis from pituitary adenoma. The unique clinical and radiological features of this case are discussed.

Diabetes Insipidus↗
PubMed1995

Acute gastric mucosal lesions associated with cytomegalovirus infection in a non-immunocompromised host.

A 75-year-old woman with epigastric pain and tarry stool was admitted to our hospital, where upper gastrointestinal endoscopic study revealed multiple gastric ulcers. The endoscopic biopsy specimens obtained on the seventh hospital day disclosed a few typical intranuclear cytomegalovirus inclusions. Cytomegalovirus-DNA was detected using polymerase chain reaction in a biopsy specimen. No immunologic abnormalities were demonstrated by any laboratory tests. While only a few cases of cytomegalovirus-associated gastric ulcer in non-immunocompromised hosts have been reported, this entity may be more frequently detected when careful histological examination is performed in the active stage rather than postponed until after healing of the ulcer.

Acute Disease↗
PubMed1995

Acromegaly, diabetes insipidus, and visual loss caused by metastatic growth hormone-releasing hormone-producing malignant pancreatic endocrine tumor in the pituitary gland. Case report.

The case of a 52-year-old woman with acromegaly, diabetes insipidus, and visual impairment caused by a metastatic growth hormone-releasing hormone (GRH)-produced pancreatic tumor is reported. Serum growth hormone (GH) and somatomedin C levels were elevated to 14 ng/ml (normal < 5 ng/ml), and 3.20 U/ml (normal < 1.88 U/ml), respectively. Paradoxical increases were observed in GH levels after glucose tolerance and thyrotropin-releasing hormone-stimulation tests. Biopsy of a pituitary tumor observed on computerized tomography scans and magnetic resonance studies revealed a metastatic cancer. When circulating GRH levels were measured, a marked increase in plasma GRH (1145 pg/ml; normal < 4-1 pg/ml) was observed. The patient died of cachexia due to metastases. Postmortem examination revealed that a primary tumor, a malignant endocrine lesion, was present in the pancreas, with metastatic tumors in the pituitary, lung, liver, and adrenal glands. Synthesis and production of GRH by the tumor was demonstrated by Northern blotting and immunohistochemical analysis. The pituitary gland showed hyperplastic, but not adenomatous changes. The authors stress the importance of both exploration for an ectopic source of GRH and the search for a GH-producing pituitary adenoma when unusual signs and symptoms are seen in patients with acromegaly.

Acromegaly↗
PubMed1994

Effect of conformation of the substrate on enzymatic decarboxylation of alpha-arylmalonic acid.

The configuration and conformation of a compound are critical factors that determine whether it can be accepted by an enzyme as a substrate or not. We have examined enzyme-catalyzed decarboxylation of some alpha-substituted malonic acids and proposed that the syn-periplanar conformation is required for the substrates to be bound to the active site of the enzyme. Theoretical calculation of potential energy surfaces also supports the conclusion from experimental results.

Alcaligenes↗
PubMed1994

Incidental pituitary lesions in 1,000 unselected autopsy specimens.

PURPOSE: To elucidate the frequency of false-positive results in imaging diagnoses of a functioning pituitary microadenoma, the authors studied various kinds of incidental lesions greater than 2 mm in diameter from a larger series of pituitary glands. MATERIALS AND METHODS: One thousand pituitary glands were studied in a nonselected autopsy series. Most causes of death were acute diseases or accidents. Each gland was fixed in 10% formalin and was then cut horizontally into three or four pieces, which were prepared for usual light microscopy. RESULTS: Of 178 glands found to have incidental lesions, 61 (34%) lesions were larger than 2 mm. Included were adenomas and hyperplasias (n = 20), Rathke cysts (n = 37), infarctions (n = 2), and hemorrhages (n = 2). Seventeen (74%) of 23 laterally localized lesions were adenomas, and 33 (87%) of 38 medially situated lesions were Rathke cleft cysts. These lesions were found in 5.8%-8.3% of subjects in every generation aged 30 years or older. CONCLUSION: Incidental lesions should be considered a cause of false-positive findings (6.1%) when an imaging diagnosis is made of a functioning pituitary microadenoma.

Adenoma↗
PubMed1994

Isolated adrenocorticotrophin deficiency associated with anti-pituitary antibodies, pituitary cyst, sphenoidal cyst and pineal tumor.

This paper reports a rare case of isolated ACTH deficiency associated with anti-pituitary antibodies, pituitary cyst, sphenoidal cyst and pineal tumor. A 68-year-old man consulted our clinic for general fatigue. Laboratory data showed low plasma adrenocorticotrophin (ACTH) and cortisol levels with blunted responses to insulin-induced hypoglycemia and corticotrophin releasing factor (CRF). Urinary 17-OHCS was low but responded to ACTH-Z administration. No other pituitary functions were impaired. Antibodies to the cytoplasm of rat pituitary and the surface of GH3 cells were detected in the serum. The magnetic resonance imaging (MRI) showed a high signal intensity mass in the anterior pituitary and in the sphenoidal sinus in both T1 and T2 weighted images as well as a low signal intensity mass in a T1 weighted image of the pineal region. Transsphenoidal surgery was performed to resect the mass in the sphenoid sinus and in the pituitary. Pathological studies showed a benign cyst in the sphenoid sinus, and fibrous degeneration and decreased basophils in the pituitary. No infiltrative mononuclear cells were detected in the pituitary. Immunohistochemical studies revealed a decrease in the number of ACTH-producing cells in the pituitary. The patient was well maintained by glucocorticoid replacement without any growth of a possibly benign pineal tumor.

Adrenocorticotropic Hormone↗
PubMed1994

Follow-up laparoscopy in patients with ovarian cancer.

Between 1982 and 1990, two hundred and fourteen consecutive laparoscopies were performed on 75 patients with epithelial ovarian cancer when the disease appeared to be clinically in complete remission according to simultaneous CT scan or ultrasonography. Evaluation were based on macroscopic findings through the laparoscope, by cytologic examination of ascitic and peritoneal washings and by intraperitoneal biopsy. The results were positive in 34 laparoscopies for 19 patients, suspicious in 15 laparoscopies for 13 patients and negative in 164 laparoscopies. the intraperitoneal recurrence rate after negative second-look laparoscopy was 14.0% as a whole, and 4.5% in cases with more than two consecutive negative evaluations. Serum CA-125 levels exhibited and elevation in 28 of 34 positive laparoscopies before treatment and remained within the normal range in 22 (78.6%) of the 28 cases after treatment despite positive follow-up laparoscopies. The repeated laparoscopies offer the advantage of lowering the false negative rate. This will enable early detection of intraperitoneal recurrence, better prognoses and reduction of unnecessary laparotomies.

Female↗