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Biomedical subjects

Y Hama

Publications and source records attributed to Y Hama.

At least 55 records · Page 3Linked to original sources
PubMed1999

Quantitative anhydrous mercaptolysis of algal galactans followed by HPLC of component sugars.

This paper describes a new HPLC method for the sugar analysis of algal galactans containing 3,6-anhydrogalactose, which is readily destroyed during usual acid hydrolysis and methanolysis. By anhydrous mercaptolysis of galactans at 60 degreesC for 6 h with the newly developed solvent system, 0.5 N HCl/[ethanethiol:methanol (2:1, v/v)], component sugars, including 3,6-anhydrogalactose, were liberated quantitatively as their diethyl dithioacetals. The resultant sugar diethyl dithioacetals were found to have strong UV-absorption (absorption maximum of 3,6-anhydrogalactose diethyl dithioacetal in water, 191-192 nm; molar extinction coefficient, 4,400). The sugar diethyl dithioacetals were then resolved simultaneously within 15 min by reversed phase HPLC with 30% acetonitrile as the eluent and detected by UV-absorption at 215 nm. Amounts of sugar diethyl dithioacetals less than 50 pmol can be determined without further derivatization.

Absorption↗
PubMed1999

Pseudogout attack associated with chronic thyroiditis and Sjögren's syndrome.

A 66-year-old woman, diagnosed with chronic thyroiditis at age 63, presented with anorexia and fatigue. Therapy for the chronic thyroiditis consisted of levothyroxine sodium (100 microg/day). Her symptoms were attributed to the insufficient supply of levothyroxine sodium. Following a dosage increase to 150 microg/day, she suffered from an acute attack of pseudogout. Clinical features were complicated by Sjögren's syndrome, which appeared after treatment onset. Pseudogout was effectively treated by colchicine after administration of diclofenac sodium failed to alleviate the symptoms. Pseudogout is a recognized complication of thyroid replacement therapy, but association with Sjögren's syndrome has not been previously reported.

Aged↗
PubMed1999

Transcatheter embolization of a superior mesenteric artery pseudoaneurysm. A case report.

A 61-year-old man, with pseudoaneurysm of the superior mesenteric artery presenting with gastrointestinal bleeding, was successfully treated by transcatheter embolization using interlocking detachable coils. During the following observation time of 10 months, the patient had no sign of gastrointestinal bleeding. We underline the importance and feasibility of transcatheter embolization as the first-line treatment in such pseudoaneurysms.

Aneurysm, False↗
PubMed1998

A gas chromatographic method for the sugar analysis of 3,6-anhydrogalactose-containing algal galactans.

This paper describes a new gas chromatographic method for the compositional analysis of algal galactans containing 3,6-anhydrogalactose, which is readily destroyed in usual acid hydrolysis and methanolysis. Mercaptolysis of galactans was carried out under an anhydrous condition using the newly developed solvent system, an ethanethiolic HCl solution which had been prepared by blowing dry HCl gas into ethanethiol. By heating galactans in 0.5 N HCl/ethanethiol at 60 degrees C for 12 h, component sugars including 3,6-anhydrogalactose were released quantitatively as their diethyl mercaptals. The monosaccharide diethyl mercaptals were trimethylsilylated and analyzed by gas-liquid chromatography. Each component monosaccharide was detected as a single peak since neither anomeric nor structural isomers can be produced by mercaptolysis. Furthermore, the solvent system was improved by the addition of methanol in a ratio (2/1, v/v) of ethanethiol to methanol. Heating of galactans at 60 degrees C in 0.5 N HCl/[ethanethiol:methanol (2/1, v/v)] released more rapidly and quantitatively monosaccharide diethyl mercaptals without any formation of monosaccharide methyl glycosides. The present method was applicable to not only algal galactans but also algal powders.

Carbohydrate Sequence↗
PubMed1998

Novel V184E MEN1 germline mutation in a Japanese kindred with familial hyperparathyroidism.

We studied the MEN1 gene in a kindred where three patients (the proposita and two of her sons) were affected with hyperparathyroidism. By polymerase chain reaction (PCR)-based direct sequencing of 10 exons of MEN1, a novel germline mutation was identified in the proposita. This mutation, a T-to-A transition at codon 184 in exon 3, predicts an amino acid change from valine to glutamine (V184E). PCR-single-strand conformational polymorphism (PCR-SSCP) analysis of exon 3 followed by sequencing showed the same mutation in the two sons, and in two clinically normal granddaughters of an affected son. Since the T-to-A substitution segregated with the disorder in the kindred except for the granddaughters and it was not detected in 100 alleles from 50 normal individuals, the change observed in MEN1 is not a polymorphism, but causes familial hyperparathyroidism. Thus the two grandchildren with the mutation were diagnosed as presymptomatic carriers.

Adolescent↗
PubMed1998

Bilateral Synchronous Spindle Cell, Apocrine and Scirrhous Carcinoma Breast Cancer in a Case of Malignant Lymphoma.

An unusual case of synchronous bilateral breast cancer occurring during combination chemotherapy and radiation to the outside of the breast for malignant lymphoma is reported. Two histologically rare carcinomas, spindle cell carcinoma and apocrine carcinoma, were observed in this case. A 77-year-old woman, who had been treated for stage IIIA non-Hodgkin's lymphoma, developed bilateral breast tumors. Aspiration biopsy cytology findings of the tumor in the left breast showed several clusters of adenocarcinoma cells and some large atypical spindle shaped cells, which suggested spindle cell carcinoma. The cytologic findings of the right breast tumor were highly suggestive of scirrhous carcinoma. A modified radical mastectomy was performed on both breasts. Pathological examination disclosed two separate cancer lesions in the left breast. The lesion which had been detected before the operation, was a spindle cell carcinoma. Another lesion, detected for the first time by pathological examination, was an apocrine carcinoma. The lesion in the right breast was a scirrhous carcinoma. Since non-invasive fociwere detected in these three cancer lesions, each lesion was thought to be a primary cancer. All dissected bilateral axillary lymph nodes showed malignant lymphoma. Immuno-histochemistry of the spindle cell carcinoma revealed positive immunoreactivity for cytokeratin, which suggested the epithelial as well as mesenchymal nature of this tumor. Synchronous existence of malignant lymphoma and three independent breast cancers including spindle cell carcinoma and apocrine carcinoma is very rare.

Journal Article↗
PubMed1998

Changes in thyroid function and immunological parameters long after subtotal thyroidectomy for Graves' disease.

OBJECTIVE: To find out whether subtotal thyroidectomy results in long term stable functional and immunological remission in patients with Graves' disease. DESIGN: Retrospective study. SETTING: Teaching hospital, Japan. SUBJECTS: 176 patients who underwent subtotal thyroidectomy for Graves' disease, 1970-79. INTERVENTION: Follow up surveys in 1984 and 1992. MAIN OUTCOME MEASURES: Changes in thyroid function, antibody titres, and lymphocyte subsets. RESULTS: 29/79 patients (39%) who were euthyroid in 1984 had evidence of thyroid dysfunction in 1992. Of the 8 patients with latent hypothyroidism in 1984, 3 (38%) had become euthyroid by 1992, and none required treatment. Of the 29 patients who were hypothyroid in 1984, 5 had latent hypothyroidism and 1 was euthyroid in 1992, and of the 18 patients with recurrent hyperthyroidism in 1984, 1 had become euthyroid by 1992. The number of positive titres to TSH-binding inhibitory immunoglobulin was significantly higher in the recurrence group (31/36, 86%) compared with the hypothyroid (7/26, 27%), latent hypothyroidism (8/37, 22%), and euthyroid (22/77, 29%) groups (p < 0.01). There were also significant differences in the mean (SD) number of Leu HLA DR subsets between the control (17 (3), n = 18) and recurrence (21 (6), n = 38), hypothyroid (22 (6), n = 35), latent hypothyroidism (22 (6), n = 22), and euthyroid (22 (9), n = 64) groups (p < 0.002). There were no differences in the number of T cell subsets among the groups. CONCLUSION: Treatment of Graves' disease by subtotal thyroidectomy does not necessarily result in stable late functional or immunological remission. Long term follow up of such patients may be necessary.

Antigens, CD↗
PubMed1998

Effectiveness of preoperative radioactive iodine (131I) therapy for locally advanced papillary thyroid cancer: a case report.

We report here the effectiveness of preoperative radioactive iodine-131 (131I) therapy for locally advanced thyroid cancer. A 57-year-old woman demonstrated a hard neck tumor that markedly invaded the surrounding organs. The cytological diagnosis of the tumor using fine-needle aspiration biopsy was papillary carcinoma. Because curative resection of the tumor appeared difficult at her first visit, 131I therapy was performed prior to surgery and was more useful than expected. After 3 131I treatments, the tumor size was greatly reduced, and the patient underwent a curative operation. Histopathological diagnosis was well differentiated papillary carcinoma, pT4 and pN1b. The postoperative clinical course was uneventful. There have been no definitive reports using 131I as preoperative treatment for inoperable thyroid cancer. We suggest that 131I therapy may also be beneficial as neoadjuvant therapy for locally advanced thyroid carcinoma.

Biopsy, Needle↗
PubMed1998

Spectroscopic investigation on the interaction of NCA0424, a potent antitumor indoloquinoxaline derivative, with DNA.

NCA0424 (1), an indoloquinoxaline derivative, has a potent antitumor activity against in vitro and in vivo tumor models. To elucidate its structure-activity relationship, the interactions with various B-form DNAs were investigated by thermal denaturation, viscosity and circular dichroism (CD) measurements. The thermal stability of the DNA duplex was increased by the interaction with 1, and preferable binding for alternative purine-pyrimidine base sequence was suggested. Comparative viscometric measurements with ethidium bromide (an intercalator) and distamycin (a minor groove binder) suggested that 1 is an intercalator. The interaction of DNA with 1 revealed a new CD band at 340-390 nm. Taking advantage of this induced CD band, the equilibrium binding constants were determined for various DNAs, and the binding preference of 1 for the alternative purine-pyrimidine base sequence, especially for the case of guanine as purine base, was indicated. The appearance of the induced CD band implies the importance of 1 side chain for the effective and/or stable intercalation of the aromatic ring into the DNA base pair.

Antineoplastic Agents↗
PubMed1998

Expression of fibroblast growth factor-2 and fibroblast growth factor receptor-1 in thyroid diseases: difference between neoplasms and hyperplastic lesions.

We studied the expression of both fibroblast growth factor-2 (FGF-2) and FGF receptor-1 (FGFR-1) in various histological types of human thyroid neoplastic and hyperplastic tissues to clarify the biological behavior of FGF-2. A total of 37 malignant tumors (24 papillary carcinomas, 10 follicular carcinomas, 3 anaplastic carcinomas), 8 follicular adenomas, and 12 adenomatous goiters were examined by immunohistochemical methods. With immunohistochemical staining, both FGF-2 and FGFR-1 were frequently detected in human thyroid carcinoma (79.2 to 100% and 80 to 100%, respectively). In thyroid hyperplastic lesions such as adenomatous goiter, the FGF-2 immunoreactivity in follicular cells was detected in 2 of 12 adenomatous goiters (16.7%). In contrast, FGFR-1 immunoreactivity was detected in 66.7% of cases of this disease. The endothelial cells of microvessels in the stroma adjacent to the neoplasms and hyperplastic lesions also showed cytoplasmic FGF-2 immunoreactivity. The difference between FGF-2 and FGFR-1 expression in adenomatous goiters was statistically significant (P<0.05). Furthermore, the difference in FGF-2 immunoreactivity between carcinoma and adenomatous goiter was statistically significant (P=0.0001). The present investigation demonstrated the possibility of an autocrine mechanism of action of FGF-2 in human thyroid carcinoma. Moreover, in thyroid hyperplastic lesions, FGF-2 derived from the stroma might be involved in the formation of nodular and/or diffuse goiters.

Adenocarcinoma, Follicular↗
PubMed1998

Clinical significance of the increased multidrug resistance-associated protein (MRP) gene expression in patients with primary breast cancer.

The efficacy of cancer treatment is limited by either intrinsic or acquired resistance to various chemotherapeutic agents. To evaluate the clinically important factors related to prognosis in primary breast cancer retrospectively, we investigated the expression of the following genes involving acquirement of drug resistance: multidrug resistance 1 (MDRl), multidrug resistance-associated protein (MRP), and topoisomerase (Topo) I, II alpha, and II beta. Using an RT-PCR method, we semiquantified the gene expression level in untreated stage II breast cancer tissue (n = 27) and noncancerous breast tissue (n = 10). Among the 27 cancer patients, who were all treated by adjuvant chemoendocrine therapy after surgery, 10 patients showed relapse within the following 10 years whereas 17 patients did not. The gene expression levels of MDRl, MRP, and Topo I, II alpha, and II beta were normalized to the level of the beta 2-microglobulin RT-PCR product. MRP mRNA expression was detected in 70% of the breast cancer tissues and its expression levels were significantly increased in the cancer group compared with the noncancerous breast tissues. Furthermore, the MRP level was much higher in the relapsed patient group. On the other hand, there were no significant differences in the MDRl mRNA levels between the noncancerous and cancer groups. Although Topo II alpha mRNA was not detected in noncancerous breast tissues, it was detected in 52% of the breast cancer tissues. In cancer patients, no significant difference in Topo II alpha mRNA levels was observed between the relapsed and nonrelapsed groups. These findings suggest that MRP might be used as one of the markers for poor prognosis in patients with breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Interaction of GM2 activator protein with glycosphingolipids.

GM2 activator protein is a protein cofactor that has been shown to stimulate the enzymatic hydrolysis of both GalNAc and NeuAc from GM2 (Wu, Y. Y., Lockyer, J. M., Sugiyama, E., Pavlova, N.V., Li, Y.-T., and Li, S.-C. (1994) J. Biol. Chem. 269, 16276-16283). To understand the mechanism by which GM2 activator stimulates the hydrolysis of GM2, we examined the interaction of this activator protein with GM2 as well as with other glycosphingolipids by TLC overlay and Sephacryl S-200 gel filtration. The TLC overlay analysis unveiled the binding specificity of GM2 activator, which was not previously revealed. Under the conditions optimal for the activator protein to stimulate the hydrolysis of GM2 by beta-hexosaminidase A, GM2 activator was found to bind avidly to acidic glycosphingolipids, including gangliosides and sulfated glycosphingolipids, but not to neutral glycosphingolipids. The gangliosides devoid of sialic acids, such as asialo-GM1 and asialo-GM2, and the GM2 derivatives whose carboxyl function in the NeuAc had been modified by methyl esterification or reduction, were only very weakly bound to GM2 activator. These results indicate that the negatively charged sugar residue or sulfate group in gangliosides is one of the important sites recognized by GM2 activator. For comparison, we also studied in parallel the complex formation between glycosphingolipids and saposin B, a separate activator protein with broad specificity to stimulate the hydrolysis of various glycosphingolipids. We found that saposin B bound to neutral glycosphingolipids and gangliosides equally well, and there was an exceptionally strong binding to sulfatide. In contrast to previous reports, we found that GM2 activator formed complexes with GM2 and other gangliosides in different proportions depending on the ratio between the activator protein and the ganglioside in the incubation mixture prior to gel filtration. We were not able to detect the specific binding of GM2 activator to GM2 when GM2 was mixed with GM1 or GM3. Thus, the specificity or the mode of action of GM2 activator cannot be simply explained by its interaction with glycosphingolipids based on complex formation. The binding of GM2 activator to a wide variety of negatively charged glycosphingolipids may indicate that this activator protein has functions other than assisting the enzymatic hydrolysis of GM2.

Brain Chemistry↗
PubMed1997

Squamous cell carcinoma arising from thyroglossal duct remnants: report of a case and results of immunohistochemical studies.

We report on the case of a 57-year-old male found to have squamous cell carcinoma (SCC) arising from thyroglossal duct remnants. The patient presented with an asymptomatic tumor in his anterior neck which was immovable on palpation. Aspiration biopsy cytology revealed class V malignancy with many atypical clusters and marked keratinization. After preoperative radiation, a radical operation employing Sistrunk's procedure with bilateral neck dissection was performed. Histopathological examination confirmed a diagnosis of moderately differentiated SCC, but revealed ciliated columnar epithelium in the walls of the cyst without a normal layer of squamous cells. Furthermore, immunohistochemical studies demonstrated the tumor to be negative for thyroglobulin staining, but positive for cytokeratin and carcinoembryonic antigen. These histopathological findings proved attributable to squamous metaplasia occurring in the ciliated columnar epithelium of the thyroglossal duct. Thus, SCC might originate in the metaplastic portion of the thyroglossal duct remnants. Although the prognosis associated with SCC in the thyroglossal duct is not as optimistic as that associated with papillary carcinoma, no evidence of recurrence has been observed in this patient in the 7 years since his operation. This suggests the effectiveness of our therapeutic approach for this unusual disease.

Carcinoma, Squamous Cell↗
PubMed1997

Postoperative outcome of insufficient surgery for small differentiated thyroid carcinoma.

We performed conservative surgery for small differentiated thyroid carcinoma, but also inadvertently carried out minimal insufficient surgery, such as enucleation (Ex) or partial lobectomy (pLx) without regional node dissection for malignant thyroid nodules. In this study, the long-term postoperative outcome after such insufficient surgical treatment was evaluated. Of 348 patients with differentiated thyroid carcinoma who underwent initial surgery between 1953 and 1976, 84 underwent either Ex or pLx and their records are herein reviewed. The frequency of recurrence from the remnant gland or regional lymph nodes was examined in relation to the tumor diameter (< or = 1.0 cm, tis; 1.0 cm-2.0 cm, t1; > 2.0 cm, t2). After Ex/pLx, the recurrence rate in the tis group was 13.3% and not significantly different from that (13.6%) in the t1 group. The recurrence rate was notably increased in the t2 group. Moreover, there was no significant difference between the recurrence rate in the tis and t1 groups after Ex/pLx and that after lobectomy with nodal dissection. These results suggest that a reoperative procedure with a more extensive thyroidectomy and neck dissection might not necessarily be required immediately after minimal insufficient surgery is inadvertently carried out in patients with small differentiated thyroid carcinoma measuring 2.0 cm in diameter or less.

Adolescent↗
PubMed1997

Germline mutations of the APC gene in two Japanese adenomatous polyposis patients.

Germline mutations of the adenomatous polyposis coli (APC) gene have been reported in patients with familial adenomatous polyposis (FAP) and are believed to be an early event in colorectal carcinoma. We report the results of screening for germline mutations of the APC gene in 4 cases of 2 kindreds using non-radioactive PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) analysis. The mutation in kindred 1 was a 4 bp deletion at codon 849 in exon 15, resulting in a frameshift leading to truncation of the APC gene product. In kindred 2, a transversion of C to G at codon 2038 was observed, resulting in an amino acid change from leucine to valine. In this case, it is possible to screen presymptomatic diagnosis easily and quickly by digestion with restriction enzyme EcoNI.

Adenomatous Polyposis Coli↗
PubMed1997

Therapeutic efficacy of the angiogenesis inhibitor O-(chloroacetyl-carbamoyl) fumagillol (TNP-470; AGM-1470) for human anaplastic thyroid carcinoma in nude mice.

TNP-470 (AGM-1470), a synthetic analog of fumagillin (6-chloroacetyl-carbamoyloxy-4-(1,2-epoxy-1,5-dimethyl- 4-hexenyl)-5-methoxy-1-oxaspiro [2,5] octane 1, has been reported to reduce the supply of nutrients to experimental tumors by inhibiting angiogenesis. In this study, we investigated anti-tumor activity of TNP-470 against human thyroid anaplastic carcinoma with a view to developing a new treatment for this thyroid tumor. A transplantable tumor was established from thyroid anaplastic carcinoma of a 78-year-old woman, as a xenograft in nude mice (BALB/c, nu/nu, male). This transplantable tumor, with chromosomal abnormality was shown to be non-functional in excretory hormones and to preserve morphological characteristics of the original anaplastic tumor tissue. TNP-470 was given at a dose of 50 mg/kg b.w. to nude mice transplanted with human thyroid anaplastic carcinoma by different routes of administration: intratumoral, peritumoral, subcutaneous and intraperitoneal. Intratumoral and peritumoral administration were effective, and especially the TNP-470 administered by the former route completely inhibited tumor growth. Immunohistochemical analysis using anti-factor VIII antibody revealed the density of microvessels to be significantly decreased by local administration of TNP-470 (intratumoral administration, 7.8 +/- 2.9/mm2, control, 27.0 +/- 6.3/mm2; peritumoral administration, 9.7 +/- 2.6/mm2, control, 21.1 +/- 5.1/mm2). Our findings suggested the possibility of clinical application of TNP-470 to control the growth of human anaplastic thyroid carcinoma.

Aged↗
PubMed1997

Development of Graves' disease after surgical treatment for thyroid nodules: report of four cases.

We report herein rare cases who developed hyperthyroid Graves' disease after surgical treatments for thyroid nodules. We have seen only 4 such cases in the course of 1680 consecutive cases (0.24%) of thyroidectomies in which partial thyroidectomy was carried out from 1966 to 1993. It is of interest that because 2 of these three cases (67%) were associated with positive TGHA and/or MCHA at the time of surgery, the presence of autoimmune thyroiditis may predispose to Graves' disease, but surgical treatment of the thyroid glands may not be related to the development of Graves' disease, because the hyperthyroid symptoms appeared 2 to 27 years (mean: 12 years) after the surgery.

Adult↗