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Y Tajima

Publications and source records attributed to Y Tajima.

At least 19 recordsLinked to original sources
PubMed2006

The thyroid gland in bottlenose dolphins (Tursiops truncatus) from the Texas coast of the Gulf of Mexico: normal structure and pathological changes.

Fresh thyroid glands (n=60) from Atlantic bottlenose dolphins that died after stranding along the Texas coast between 1991 and 2005 were examined. Organ weight ranged from 11 g in a neonate (length 109 cm) to 58 g in a large (249 cm) male. More typical weights were 25-45 g (mean=30.6 g). Glands tended to be larger in pregnant and lactating females (mean 37.4 g; n=5) than in non-pregnant animals of comparable size. In infancy, the gland tended to be compact, relatively homogeneous, and sometimes partly lobular, but with advancing age it became more lobular, the lobules being defined by fibrous bands. In one 8-year-old female (233 cm), and in a large male (295 cm) aged>25 years the gland was represented by a cluster of lobules. Lobulation was not necessarily accompanied by increased weight, distinguishing it from hyperplasia. With age, variation in follicle size and colloid density tended to increase. Two animals (3%) had adenomas and five (8%) had discrete hyperplastic nodules, not to be confused with lobulation. Five (8%) had macroscopically identifiable colloid-filled cysts (1-4 mm in diameter). Nine animals (15%) had squamous cysts (4-15 mm) containing creamy white fluid. Other abnormalities included patchy or diffuse interstitial fibrosis (six cases, 10%) amyloidosis (two cases), thyroiditis (one case) and vasculitis (one case). No malignant neoplasms were found. Cells presumed to be C cells (light cells, parafollicular cells) were identified immunohistochemically with synaptophysin antibody.

Adenoma↗
PubMed2005

Experimental study on pathogenesis and histomorphology of early carcinoma of the extrahepatic bile duct in the Syrian hamster.

To elucidate the pathogenesis of carcinomas in the extrahepatic bile duct, we investigated the histomorphological characteristics of adenomas and early carcinomas induced in the extrahepatic bile duct of hamsters. Syrian hamsters underwent a cholecystoduodenostomy along with a dissection of the common duct, while also being administered N-nitrosobis(2-oxopropyl)amine (BOP). The tumors that arose from the extrahepatic bile duct included 10 adenomas and 55 early carcinomas in 56 of the 156 hamsters sacrificed. All the adenomas were found to be polypoid in shape. The early carcinomas, which were restricted within the mucosal layer of the bile duct, showed the following three different growth patterns: (1) protruding type in 41 (75%), consisting of 27 polypoid and 14 papillary tumors; (2) superficial spreading type in 9 (16%); and (3) periductal glandular type in 5 (9%). There were no depressed tumors observed. Carcinomas existing either alone or associated with adenomas were evident in 12 (22%) tumors, and 11 of these were polypoid. Atypical papillary hyperplasia within the tumor mass was noted in 22 early carcinomas (40%) and was particularly prominent in papillary type tumors. These results support the concept of an adenoma-carcinoma sequence in the majority of polypoid tumors of the extrahepatic bile duct. Atypical papillary hyperplasia might also be premalignant, and these precursor lesions should reflect the growth patterns of tumors, at least in the early stage of tumorigenesis.

Adenoma↗
PubMed2004

Gastric and intestinal phenotypic marker expression in gastric carcinomas and recurrence pattern after surgery-immunohistochemical analysis of 213 lesions.

Both gastric and intestinal phenotypic markers are known to be expressed in gastric carcinomas, irrespective of their histologic type. In the present study, the relation between gastric and intestinal phenotypic marker expression in gastric carcinomas and the recurrence pattern after surgery was examined. The phenotypic marker expression of the tumour was determined by examining the expression of human gastric mucin (HGM), MUC6, MUC2 and CD10 in 213 advanced gastric carcinomas in 213 patients who had undergone a curative resection (97 died from recurrent gastric carcinoma and 116 were alive without recurrence at the end of the follow-up period). Tumours were classified into gastric (G), gastric and intestinal mixed (GI), intestinal (I) or unclassified (UC) phenotypes according to the immunopositivity of HGM, MUC6, MUC2 and CD10 stainings. The incidence of HGM-positive tumours and MUC2-negative tumours was significantly higher in tumours with peritoneal recurrence than in tumours without recurrence (73.3%, 44 out of 60 cases vs 54.3%, 63 out of 116 (P=0.022); and 70.0%, 42 out of 60 vs 38.8%, 45 out of 116 (P=0.0002), respectively). The incidence of G-phenotype tumours was also significantly higher in tumours with peritoneal recurrence than in tumours without recurrence (58.3%, 35 out of 60 cases vs 28.4%, 33 out of 116 (P=0.0002)). The incidence of MUC2-negative tumours and CD10-positive tumours was significantly higher in tumours with haematogenous recurrence than in tumours without recurrence (62.5%, 20 out of 32 cases vs 38.8%, 45 out of 116 (P=0.028); and 43.8%, 14 out of 32 vs 23.3%, 27 out of 116 (P=0.039); respectively). Our present findings show that the gastric and intestinal phenotypic marker expression of the tumour, determined by immunohistochemical staining for HGM, MUC6, MUC2 and CD10, can be used to predict the pattern of gastric carcinoma recurrence after curative resection.

Aged↗
PubMed2004

An intraductal papillary component is associated with prolonged survival after hepatic resection for intrahepatic cholangiocarcinoma.

BACKGROUND: The outcome after surgery for intrahepatic cholangiocarcinoma (ICC) is dismal and data on long-term survival are not available. This study evaluated prognostic indicators and characteristic features of long-term survivors after hepatic resection for ICC. METHODS: Thirty-one patients who had undergone hepatic resection for ICC were studied. Univariate and multivariate survival analyses of clinicopathological data included an intraductal papillary carcinoma component (IDPCC) in the tumour, which was defined as the histological demonstration of cancer cells growing in a papillary fashion into the lumen of the large bile duct. RESULTS: The overall cumulative survival rate after hepatic resection for ICC was 51.2 per cent at 1 year and 24.5 per cent at 5 years, with a mean(s.d.) survival time of 11(4) months. The presence of IDPCC (P = 0.003), curative resection (P = 0.009) and the absence of perineural invasion (P = 0.040) were identified as favourable independent prognostic factors in multivariate analysis. Eight patients with IDPCC had a 5-year survival rate of 87.5 per cent and a mean(s.d.) survival time of 69(13) months. All seven patients who survived for more than 5 years after surgery had IDPCC, regardless of the gross appearance of the tumour. CONCLUSION: An IDPCC in the tumour resulted in long-term survival after hepatic resection for ICC.

Adult↗
PubMed2004

Use of the time-signal intensity curve from dynamic magnetic resonance imaging to evaluate remnant pancreatic fibrosis after pancreaticojejunostomy in patients undergoing pancreaticoduodenectomy.

BACKGROUND: This study assessed the value of the time-signal intensity curve (TIC) obtained from dynamic magnetic resonance imaging (MRI) in the evaluation of remnant pancreatic fibrosis after pancreaticojejunostomy in patients undergoing pancreaticoduodenectomy. METHODS: Two modes of pancreaticojejunostomy-duct-to-mucosa anastomosis (DMA; 24 patients) and pancreatojejunoserosal anastomosis (PJSA; 22 patients)-were used in 46 consecutive patients undergoing pancreaticoduodenectomy. All patients underwent dynamic contrast-enhanced MRI of the pancreas before pancreaticoduodenectomy. Retrospective review of the pancreatic magnetic resonance images and histological examination of the pancreas were performed, and the patterns of TICs from dynamic MRI were compared with the degree of pancreatic fibrosis. Dynamic MRI of the residual pancreas was carried out for 1-3 years after pancreaticoduodenectomy in 26 patients (14 DMA, 12 PJSA) who had a histologically verified normal pancreas with no fibrosis at the time of pancreaticoduodenectomy. RESULTS: Evaluation of preoperative dynamic magnetic resonance images showed that a pancreatic TIC with a rapid rise to a peak followed by a rapid decline (type I) was characteristic of a normal pancreas without fibrosis. Pancreatic TICs with a slow rise to a peak followed by a slow decline or a plateau (types II and III) indicated a fibrotic pancreas. Postoperative pancreatic MRI demonstrated that six of 12 patients with a PJSA had a type II TIC, whereas 12 of 14 patients with a DMA had a type I curve (P = 0.046). CONCLUSION: The TIC obtained from dynamic MRI is a reliable indicator of fibrosis in the remnant pancreas after pancreaticoduodenectomy. Use of a DMA was associated with a lower risk of pancreatic fibrosis 1-3 years after surgery than a PJSA.

Adult↗
PubMed2001

Expression of glycoconjugates bearing the Lewis X epitope during neural differentiation of P19 EC cells.

The Lewis X (Le(x)) bearing glycolipids were noticeably increased in amounts during the course of neural differentiation of P19 EC cells induced by retinoic acid (RA, all-trans form). Applying neoglycolipid technology and in situ TLC-LSIMS, the oligosaccharide chains of these scarce Le(x) bearing glycolipids were partially characterized after released by endoglycoceramidase and subsequent conversion into neoglycolipids. In order to understand the enzymatic basis for the expression of Le(x) bearing glycolipids, we measured glycolipid, glycoprotein and oligosaccharide fucosyltransferase (Fuc-T) activities using appropriate substrates in P19 EC cells with or without RA treatment. All three Fuc-Ts were increased after RA treatment and the highest activity was in the differentiated neural cells. We then investigated the two possible Fuc-T genes that might be responsible for these changes using RT-PCR analysis. Mouse Fuc-TIX (mFuc-TIX) transcript was detected in all cell types but it was only strongly expressed in RA-induced aggregates and neural cells. In the case of mouse Fuc-TIV (mFuc-TIV) gene, its transcript was only detectable in RA-induced aggregates and not found in either undifferentiated or RA-induced neural cells. These results strongly support that RA induces only a transient expression of the mFuc-TIV gene in cell aggregates but a more persistent expression of the mFuc-TIX gene at the transcription level throughout neural cell differentiation. The mFuc-TIX gene is probably the main cause for the increased expression of Le(x) glycoconjugates during neural differentiation of P19 EC cells.

Animals↗
PubMed2001

Peripheral ameloblastoma with potentially malignant features: report of a case with special regard to its keratin profile.

A peripheral ameloblastoma with atypical features occurring on the left maxillary alveolar ridge of 40-year-old man is described, along with an immunohistochemical profile of its cytokeratin (CK). The lesion apparently originated from the surface gingival epithelium. The tumor nests or strands were highly cellular with a variable degree of squamous differentiation and microcyst formation. Occasional mitotic figures and dystrophic calcification, both of which are not seen in conventional ameloblastomas, were also observed. The tumor infiltrated deep into the alveolar mucosa, including the periodontal ligament, and showed histological and topographical evidence of atypism, resulting in resorption of the underlying alveolar bone. On the CK immunohistochemistry, CK19 was demonstrated in all the types of neoplastic epithelia, including microcyst-forming cells, densely packed round or spindle cells within the tumor nests, cells with squamous metaplasia, and peripheral tall columnar cells. The CK immunohistochemical findings suggest the lesion's cell of odontogenic origin; they may reflect an immature phenotypic expression of cell differentiation in the odontogenic epithelia during the tumor growth in the gingival mucosa.

Adult↗
PubMed2001

Malignant adenomyoepithelioma of the breast: a non-tubular and matrix-producing variant.

Two women, aged 82 and 58 years old, cases 1 and 2, respectively, with the non-tubular and matrix-producing variant of malignant adenomyoepithelioma (MAM) of the breast are described. The tumors were 20 and 35 mm in diameter, respectively, and had cut surfaces with a tan-white-colored appearance and vague lobulation. Although both tumors showed marked central necrosis and a high level of mitoses, the tumor cells had relatively monomorphous nuclei and exhibited only mild atypia. The invasive component was predominantly trabecular and lobular, and the intraductal component demonstrated a focal-comedo pattern. The cytoplasm of the tumor cells was rather scanty, vacuolar or pale with ill-defined borders. The tumor in case 2 contained intermingled spindle-shaped cells. The stroma of both tumors resembled that of pleomorphic adenoma, containing a myxoid and chondroid matrix and, in case 2, cartilage and mature bone. Immunohistochemical and ultrastructural analyses of both tumors revealed dual cytological differentiation, predominantly of myoepithelial cells with secretory epithelial cells intermingled haphazardly. Although these tumors resembled metaplastic carcinomas, particularly matrix-producing carcinomas, they showed marked myoepithelial differentiation without overt tubular differentiation, a pattern quite different from matrix-producing carcinomas and from the adenomyoepitheliomas reported so far. MAM of the breast, non-tubular and matrix-producing variant, resembles epithelioid myoepithelial carcinoma of the salivary gland and has not been reported previously in the English literature.

Aged↗
PubMed2001

Clinicopathological study of early adenocarcinoma of the gastric cardia: comparison with early adenocarcinoma of the distal stomach and esophagus.

To clarify the clinicopathological characteristics of adenocarcinoma of the gastric cardia (AGC), including its association with Barrett's esophagus and intestinal metaplasia, 49 surgically resected early AGCs (EAGCs) were examined clinicopathologically, histopathologically, histochemically, and immunohistochemically. The clinicopathological characteristics of the patients with EAGC were compared with those of 293 patients with early adenocarcinoma of the distal stomach (EADS) and 7 patients with early adenocarcinoma of the esophagus (EAE). Histochemical staining with paradoxical concanavalin A (ConA) and immunohistochemical staining with monoclonal antibodies 45M1, Ccp58, and 56C6 were performed to investigate the differentiation phenotype of the tumor. ConA and 45M1 were used for markers of the gastric phenotype, and Ccp58 and 56C6 were used for markers of the intestinal phenotype. EAGC was associated with a higher mean age (p < 0.0001), a higher male-to-female ratio (p < 0.05), a higher incidence of elevated-type tumors (p < 0.0001), a higher incidence of differentiated-type tumors (p < 0.0001), and greater depth of invasion (p < 0.05) compared with EADS. EAE was associated with a higher incidence of elevated-type tumors (p < 0.001), a higher incidence of differentiated-type tumors (p < 0.05), and larger tumor size (p < 0.05) compared with EADS. The prevalence of Barrett's esophagus in patients with EAGC was significantly lower than in patients with EAE (10.2%, 5/49 patients vs. 100%, 7/7; p < 0.0001). The prevalence of intestinal (Barrett's) metaplasia in surrounding non-neoplastic mucosa in patients with EAGC was significantly lower than in patients with EADS or EAE (36.7%, 18/49 patients vs. 72.0%, 211/293 and 85.7%, 6/7; p < 0.0001 and p < 0.05, respectively). EAGC was associated with a higher incidence of tumors that reacted positively for gastric phenotype markers alone than EADS (32.7%, 16/49 cases vs. 17.1%, 50/293; p < 0.05) and a lower incidence of tumors that reacted positively for both gastric and intestinal markers than EADS or EAE (40.8%, 20/49 cases vs. 59.7%, 175/293 and 85.7%, 6/7; p < 0.05, respectively). Our findings indicate that AGC forms a specific category different from both adenocarcinoma of the distal stomach and esophagus in terms of association with Barrett's esophagus or intestinal metaplasia, and the differentiation phenotype of the tumor.

Adenocarcinoma↗
PubMed2001

Gastric and intestinal phenotypic marker expression in gastric carcinomas and its prognostic significance: immunohistochemical analysis of 136 lesions.

OBJECTIVE: It is well known that both gastric and intestinal phenotypic cell markers are expressed in gastric carcinomas, irrespective of their histologic type. However, the clinicopathologic significance of these expressions has not yet been clarified. METHODS: We analyzed the correlations among gastric and intestinal phenotypic marker expression patterns of the tumor, clinicopathologic findings and the patient's outcome in 136 advanced gastric carcinomas. RESULTS: Phenotypic marker expression was immunohistochemically evaluated using the monoclonal antibodies 45M1 (anti-human gastric mucin; HGM), CLH5 (anti-MUC6), Ccp58 (anti-MUC2) and 56C6 (anti-CD10). All tumors were classified as gastric (G), gastric and intestinal mixed (GI), intestinal (I) or unclassified (UC) phenotype. Of the 136 gastric carcinomas, 50 (36.8%), 56 (41.2%), 21 (15.4%) and 9 (6.6%) were classified as G, GI, I and UC phenotype, respectively. The G-phenotype tumors were associated with a higher rate of undifferentiated-type and infiltrative histology as compared with the I-phenotype tumors (p < 0.05 and p < 0.001, respectively). Furthermore, both univariate and multivariate analysis of survival revealed the G-phenotype tumor to be associated with a significantly poorer outcome than the I-phenotype tumor (p < 0.05). CONCLUSION: Our present results indicate that the gastric and intestinal phenotypic marker expression pattern of tumors, determined by the combination of HGM, MUC6, MUC2 and CD10 expression, is prognostically useful for patients with gastric carcinoma.

Adenocarcinoma↗
PubMed2001

Early pancreatic cancer.

The results of surgical treatment for ordinary carcinoma of the pancreas, even now considered the only means for cure, have been dismal. In order to define early pancreatic cancer, aiming amelioration of surgical results, early pancreatic cancer has been seeked. It may be readily conceivable that the smaller the tumor size, the earlier the lesion. The relationship between tumor size and surgical results was reviewed from the literature, some of which included articles written in Japanese. Tumor size < or = 2 cm in diameter is not always an early cancer. Tumor < 1 cm could be an early cancer but does not definitely reveal long-term survival. An increase of pancreatic cancer in Japan may be strongly related with the increased elderly population. Small cystic lesions which develop in elderly persons seem to indicate carcinogenesis of ordinary ductal cancer of the pancreas. Carcinoma in situ may be an early pancreatic cancer. Early pancreatic cancer is defined as an intraductal adenocarcinoma without any invasion or with minimal invasion to the stroma, regardless of size or extent of the lesion.

Adenocarcinoma, Papillary↗
PubMed2001

Lacunary-substituted undecatungstosilicates sensitize methicillin-resistant Staphylococcus aureus to beta-lactams.

Some Keggin-structural (hetero)polyoxotungstates with a lacunary hole, such as undecatungstosilicate ([SiW11O39]8-, SiW11), greatly sensitize methicillin-resistant Staphylococcus aureus (MRSA) to beta-lactams. In this study, the effects of lacunary-substituted derivatives of SiW11 were tested to determine if the lacunary hole is required for the sensitizing effect. Initially, it was supposed that the hole functioned as a binding site that interacts with some bacterial components. However, most of the lacunary-substituted species had stronger effects than SiW11, indicating that the hole is not essential for the sensitizing effect. Undecatungsto(ferri)ferrosilicate ([SiW11O39Fe](6/5-)) was the most potent compound tested, but undecatungstocobaltosilicate ([SiW11O39Co]6-) gave better results according to the fractional inhibitory concentration index. Small lipophilic cations enhanced the sensitizing effect, but bulky cations inhibited it. This suggests that a charge interaction between the tungsten compounds and some unknown materials in the culture medium or bacterial cells plays an important role in the sensitizing effect.

Aminoglycosides↗
PubMed2001

[Two adult cases of nemaline myopathy presenting different clinical symptoms and CT findings].

We report herein two cases of nemaline myopathy which showed peculiar muscle involvement and clinical symptoms. Case 1: A 44-year-old woman had developed gradual woresening of muscle weakness. Neurologically, only flexion of her neck was found to be weak. Her muscular CT revealed mild atrophy of four extremities and the sternocleidomastoid muscles. Histological examinations with Gomori-trichrome staining revealed tiny structures whose form was compatible with nemaline rods. Moreover, electronmicroscopic examination demonstrated the lattice pattern of electron-dense structures, and they also appeared to possess structural continuity with the Z-band. Case 2: A 56-year-old woman visited our department because of neck pulsations. Neurological examinations revealed bilateral hearing disturbance, marked atrophy of neck muscles, muscle weakness in four extremities and hypoactive deep tendon reflexes. She also exhibited steppage and waddling gaits. Her muscular CT demonstrated degenerative processes in the neck muscles(splenius muscles and semispinal muscles), trapezius muscles, para-spinal muscles, deltoid muscles and gluteal muscles. Among them, the para-spinal muscles and extensor muscles of the lower limbs showed marked degeneration and had been partly replaced by fatty tissues. A muscle biopsy was performed, and the presence of nemaline rods was confirmed by Gomori-trichrome staining. Although these two cases could be diagnosed as nemaline myopathy, the clinical symptoms and muscular CT findings were not quite the same. Whether these differences might simply indicate different clinical phases during the disease progression or be of further pathogenic significance still remains unclear. Additionally, since long-term follow-up studies of nemaline myopathy are quite rare, further follow-up examinations of these cases are necessary in order to understand the clinical and pathological alterations of nemaline myopathy.

Adult↗