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Biomedical subjects

T Yashiro

Publications and source records attributed to T Yashiro.

At least 55 records · Page 3Linked to original sources
PubMed1991

Use of the o-phenylenediamine fluorescence system in the enzymatic assay of serum uric acid.

A manual enzymatic method is described for sensitive fluorometric determination of uric acid in human serum. This method is based on an enzymatic reaction with uricase to form hydrogen peroxide from uric acid and the following oxidation of o-phenylenediamine with peroxidase and hydrogen peroxide for the production of a fluorescence compound. The specificity and the selectivity in the method are due to the uricase reaction and the fluorometry, respectively. The formed fluorescence in the reaction mixture is measured at 410 nm (an excitation) and 550 nm (an emission). This enzymatic method can determine uric acid at 30-1000 microM, with a between-assay relative standard deviation of 4.35% or less. A good correlation is obtained between the present method and the colorimetric kit method.

Ascorbate Oxidase↗
PubMed1991

Prevalence of chondrocalcinosis in patients with primary hyperparathyroidism in Japan.

One hundred and thirty-two consecutive patients with primary hyperparathyroidism were studied preoperatively for the presence of chondrocalcinosis, the roentgenographic marker of calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, by obtaining radiographs of knees, wrists and pelvis. Chondrocalcinosis was found in 8 patients (6.1%), each of whom was over 50 years of age. In 72 of the patients over 50 years of age, the prevalence of chondrocalcinosis in the hyperparathyroid patients (11.1%) was greater than that found in 72 control patients (2.8%) with thyroid nodular disease who were exactly matched for age and sex, but the difference was not significant. The prevalence of chondrocalcinosis in the hyperparathyroid patients sharply increased with age. In the group in their 50's it was 4.4%, rising to 15.8% in patients in their 60's and reaching 37.5% for those over 70 years of age. Patients with chondrocalcinosis were significantly older than those without this finding (p < 0.005). Those with chondrocalcinosis also had significantly higher preoperative serum calcium levels than those without it (p < 0.05). While chondrocalcinosis was detected by taking joint radiographs in all patients with primary hyperparathyroidism, acute arthritis (pseudogout attack) occurred in only 2 of the 132 patients (1.5%) after parathyroidectomy, but this represents 25% (2 of 8) of those who had chondrocalcinosis. An attack of pseudogout may therefore be one of the most common postoperative complications of parathyroid surgery in the elderly. Considering the low incidence of pseudogout attack following parathyroidectomy, preoperative radiological studies of the knee joints are sufficient to screen for chondrocalcinosis and are recommended for patients over 60 years old in Japan.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Intercellular communication within the rat anterior pituitary gland. I. Postnatal development and changes after injection of luteinizing hormone-releasing hormone (LH-RH) or testosterone.

The postnatal development of gap junction formation and cell-to-cell communication were investigated in male rats from 10 through 40 days of age. These junctions initially appeared between adjacent folliculo-stellate cells on day 20. Their numbers increased until the animals reached the age of 40 days, when their frequency reached a level that resembled that found in adults. The ontogeny of these junctions was examined in rats treated with luteinizing hormone releasing hormone (LH-RH) or testosterone. The two hormones were injected for 1 week into rats aged 3, 13, 23, or 33 days. The appearance of gap junctions was accelerated in a similar fashion by LH-RH and testosterone, with their formation and numbers being advanced by 10 days over that observed in the untreated controls. The results suggest a role for the gonadal steroid hormones in the formation of gap junctions in the rat hypophysis.

Animals↗
PubMed1990

Mid-mediastinal parathyroid lesions: preoperative localization and surgical approach in two cases.

Although hyperfunctioning mediastinal parathyroid lesions that require median sternotomy or thoracotomy for removal are occasionally present, the majority are located in the anterior mediastinum closely associated with the thymus. Only eight cases of ectopic hyperfunctioning parathyroid tumors in the middle mediastinum have been reported. We experienced two cases of either persistent or recurrent hyperparathyroidism in which abnormal parathyroid tissue was located in the aorticopulmonary window. One of the patients had a parathyroid adenoma and the other had metastatic lesions of parathyroid carcinoma. In both cases, thallium scanning proved useful in identifying the lesions while computed tomography scan was effective for mediastinal three-dimensional localization. In one case, single photon emission computed tomography imaging with thallium proved beneficial for both identification and localization of the middle mediastinal lesion. The surgical approach used in both cases was different. In one case, left thoracotomy was performed, after which the ligamentum arteriosum was divided, and an adenoma anterior to the left main bronchus and posterior to the left pulmonary artery removed. In the other case, two metastatic tumors of parathyroid carcinoma anterior to the right main bronchus and posterior to the right pulmonary artery were resected through a median sternotomy and opening of the pericardium.

Adenoma↗
PubMed1990

Cervical thymic cyst as a cause of acute suppurative thyroiditis.

A case of acute suppurative thyroiditis following a perithyroidal abscess, which was thought to have resulted from infection of a cervical thymic cyst, is reported herein. The patient was an 8 year old asthmatic Japanese boy who originally presented with tender swelling of the left anterior neck in July, 1986. Although pharyngography could not clearly demonstrate the pyriform sinus fistula, a hypoechoic area around the left lobe of the thyroid gland was noted on ultrasonography. Incisional drainage revealed Streptococcus milleri. A diagnosis of acute suppurative thyroiditis was established, and a cystic tubular mass was surgically resected from the left perithyroidal space some time later. Histopathological examination of the specimen revealed partly cystic thymic tissue along with parathyroid tissue. These observations suggested that acute suppurative thyroiditis in this case was caused by a perithyroidal abscess and that a perithyroidal abscess may also result from infection of a cervical thymic cyst.

Acute Disease↗
PubMed1990

[The behavior of 1,4-benzodiazepine drugs in acidic media. XVI. Estimation of cis/trans isomer ratio of benzodiazepinooxazoles using nuclear magnetic resonance shift reagent].

The ratio of cis/trans isomers (referring to 11b-substituent and 2- or 3-substituent) of benzodiazepinooxazoles was estimated by using the lanthanide shift reagent (Eu(fod)3-d27) for nuclear magnetic resonance (NMR) spectroscopy. The amide carbonyl oxygen at 6-position is considered to coordinate with the reagent, because the largest downfield shifts were observed at the amide carbonyl carbon (C-6) in 13C-NMR and the amide hydrogen (H-7) in 1H-NMR. The ratios depend largely on the substituents at 11b-, 2-, and 3-positions. The cis isomer for compounds having 11b-hydrogen increases with an increase in the bulkiness of the substituents at 2-position. The cis isomer for compounds having 3-methyl group decreases with change from 11b-2'-chlorophenyl group (mexazolam) to 11b-hydrogen.

Benzodiazepines↗
PubMed1989

[Graves' disease with unusual histological findings].

We reported three cases of Graves' disease which showed unusual histological findings featuring solid follicles, multinucleated giant cells and diffuse infiltration of histiocytes as well as lymphocytes in the whole section of the resected thyroid. Characteristics of these three cases were as follows: (1) Clinically, longer duration of the disease and exophthalmos were their prevailing findings. (2) On laboratory data, antimicrosomal antibody showed extremely high titers with 100,000 to 400,000. (3) Their operative findings were different from ordinary Graves' goiters in that colors of the goiter were yellow-red or gray-red, surface was rough and coarse, consistency was firm, and adhesions with the adjacent connective tissue were noted. (4) Postoperative clinical outcome was quite similar to that of ordinary Graves' patients. From these findings, these three cases were considered to be different from either so-called Hashitoxicosis or silent thyroiditis or Graves' disease with granulomatous foci, and it was suggested that these three cases might be a subgroup of Graves' disease or another hyperthyroidism than ordinary Graves' disease. Further accumulation and analysis of such cases will be necessary in order to answer this question.

Adolescent↗
PubMed1989

Granulated 'marginal cell layer' in the rat anterior pituitary gland.

A granulated 'marginal layer cell' was observed in the lining of Rathke's residual pouch of 5 and 10 day-old rat anterior pituitary glands. Immunohistochemistry was not employed to identify the precise function of these cells. However, the cytological characteristics of nearly all of the cells indicated that they resembled GH-secreting cells, with a few displaying morphological features of corticotrophs. In pituitary glands of 5-20 day-old rats, both ends of Rathke's residual pouch extended into the pars distalis at the site of transitional zone of this lobe and of the pars intermedia. The cells within the 'invading' residual pouch contained numerous microvilli. In the middle portion of the residual pouch, cavities lined by 'marginal layer cells' had numerous microvilli and were adjoined by junctional complexes. In the adult rat pituitary gland, there were no granulated cells in the 'marginal cell layer' and no invasion of the residual pouch into the anterior lobe. From these data the possible source of the follicle and of the folliculo-stellate cells in the anterior pituitary of the rat is proposed.

Animals↗
PubMed1989

Determination of acetaldehyde in human blood by high-performance liquid chromatography using fluorometry.

A method was developed for the measurement of acetaldehyde in human blood by high-performance liquid chromatography (HPLC). The method was based on a pre-column reaction; a fluorescent substance was formed by a coupling reaction between 2 mol of cyclohexan-1,3-dione and 1 mol of acetaldehyde with ammonium acetate. The coupling compound was analyzed by HPLC and the concentration of acetaldehyde was obtained from the calibration curve drawn from the results using standard solutions. The determination was sensitive and reproducible with a range of 0.2-10 microM and a precision (coefficient of variation) of 2.43%.

Acetaldehyde↗
PubMed1989

Expression of insulin-like growth factor receptors in primary human thyroid neoplasms.

The presence of IGF-I receptors was demonstrated in normal and neoplastic tissues of human thyroid. Binding of (125I)IGF-I to thyroid membranes was dependent on time and temperature of incubation, and maximal binding was achieved at 4 degree C and 18 h of incubation. (125I)IGI-I binding was dose-dependently displaced by unlabelled IGF-I; half-maximal inhibition occurred at concentrations of 10-20 milligrams. IGF-II and insulin had relative potencies of 5 and 1% compared with IGF-I. Scatchard analysis of binding data revealed a single class of IGF-I receptors with high affinity (Ka: 1.2-8.6 x 10(9) 1/mol) in normal thyroid tissues. Affinity cross-linking and autoradiography demonstrated the type IIGF receptors. Specific binding of (125I)IGF-1 in thyroid cancer tissues (9.69 +/- 2.07% per 200 micrograms protein; mean +/- SEM, N = 8) was significantly (p less than 0.05) higher than that in the surrounding normal tissues (3.03 +/- 0.35%, N = 8). In contrast there was no difference in the binding between adenoma tissues (4.19 +/- 0.53%, N = 5) and the adjacent normal tissues (2.94 +/- 0.24%, N = 5). The higher IGF-I binding in cancer tissues was due to an increase in the binding capacity without any change in the affinity. The presence of IGF-I receptors suggests a possible role of IGF-I and its receptors in the growth of thyroid cancer cells.

Adenoma↗
PubMed1989

[Diagnosis and treatment of the precancer state in hereditary medullary thyroid carcinoma].

We attempted to elucidate the diagnosis and treatment in 11 patients with hereditary medullary thyroid carcinoma which were inherited as autosomal dominant traits. The oncogens are thought to be supported by the two-mutational event theory; the C cell hyperplasia, the first step, is the expression of the genetic mutation, which requires a subsequent somatic mutation to transform the initially mutated cell into a cancer cell. The C-cell hyperplasia was thought to be precancer state. The definitive diagnosis was established by measurement of calcitonin and CEA levels in sera. In patients with normal levels of calcitonin and CEA, the provocative test (Ca-gluconate plus pentagastrin) was useful such as in pt. no. 11,K.N.). The principle of surgery is total thyroidectomy because of multicentric occurrence in both lobes. Two patients (pt nos. 10, 11) with normal postoperative levels of provocative test underwent total thyroidectomy.

Adult↗
PubMed1988

Fine-structural and immunohistochemical study of anterior pituitary cells of Snell dwarf mice.

Snell dwarf mice display remarkable retardation of growth after birth and are known to lack prolactin (PRL), thyroid stimulating hormone (TSH) and growth hormone (GH). The aim of this study was to determine the reason for these hormonal deficiencies. We examined the fine structure of the gland and its immunohistochemical staining pattern with respect to antisera raised against PRL, TSH, GH, adrenocorticotrophic hormone (ACTH) and luteinizing hormone (LH). The gland of control mice reacted immunohistochemically against all antisera used, whereas only ACTH-producing cells (ACTH cells) and LH-producing cells (LH cells) were distinguished in the dwarf mice. ACTH cells in dwarf mice varied in cell shape, although they were similar in size to those of controls. The distribution of secretory granules in the cytoplasm varied from cell to cell. LH cells in the dwarf mice showed immature features, having poorly developed rough endoplasmic reticulum and Golgi apparatus. The cells were about half the size of controls, and secretory granules were smaller. In dwarf mice, non-granulated cells were encountered in addition to granulated ACTH and LH cells. Some of them formed small clusters, characteristic cell junctions being found between the cells; they thus appeared to be follicular cells. The above results suggest that hormone deficiency in Snell dwarf mice is a result of a defect in the hormone-producing cells in the gland.

Animals↗
PubMed1988

Gallium-67 imaging in the evaluation of thyroid malignancy.

One hundred thirty-six patients with suspected thyroid malignancy were studied prospectively with Ga-67 imaging of the thyroid and whole body. All patients subsequently had diagnoses proven by biopsy or surgical resection. Patients with malignant tumors (anaplastic carcinoma, malignant lymphoma, adenocarcinoma, medullary carcinoma, adenocarcinoma with squamous cell transformation, and metastases to the thyroid from other tumors) were examined serially after appropriate therapy. The authors draw on their own experience and a literature review to propose the following indications for Ga-67 imaging in patients with thyroid disease: 1) suspected anaplastic carcinoma or malignant lymphoma of the thyroid gland, 2) detection of distant metastases of anaplastic thyroid carcinoma and malignant lymphoma, 3) evaluation of efficacy of therapy, 4) suspected metastases to the thyroid gland from other malignancies, and 5) differentiation of malignant lymphoma from chronic thyroiditis. The strengths, limitations, and potential pit-falls of the technique are discussed.

Adult↗
PubMed1988

IgG-kappa-producing primary plasmacytoma of the thyroid gland with preoperative serum M protein.

A case of primary plasmacytoma of the thyroid gland which occurred in a 63-year-old woman is reported. Histologic and ultramicroscopic examination revealed that the excised thyroid tumor was plasmacytoma superimposed on lymphocytic thyroiditis. Immunohistological study showed that the tumor cells produced intracytoplasmic immunoglobulin (IgG-kappa). Electrophoretic and immunoelectrophoretic studies disclosed the presence of monoclonal immunoglobulin (IgG-kappa) in samples of the patient's serum which had been obtained preoperatively. After completion of irradiation therapy to the neck following tumor removal, the serum monoclonal immunoglobulin disappeared. The patient is currently alive and well without any evidence of the tumor three years after surgery.

Blood Proteins↗
PubMed1988

Pseudogout associated with primary hyperparathyroidism: management in the immediate postoperative period for prevention of acute pseudogout attack.

Three cases of pseudogout associated with primary hyperparathyroidism are reported. Preoperative radiological studies revealed association of pseudogout. Considering the frequent development of acute pseudogout attack following parathyroidectomy, prevention of a sudden decrease in the serum calcium concentration was attempted using calcium supplement therapy starting on the first postoperative day in all three cases. Serum calcium slowly decreased to the normal range, and the postoperative courses were uneventful. From these experiences, we advocate that calcium supplement therapy is worth trying for the prevention of acute pseudogout attack following parathyroidectomy.

Aged↗