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Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 343 records · Page 19Linked to original sources
PubMed1996

Detection of ret homodimers in MEN 2A-associated pheochromocytomas.

Using transfection of NIH 3T3 cells, we have recently demonstrated that multiple endocrine neoplasia (MEN) 2A mutations activate the c-Ret protein by inducing its disulfide-linked homodimerization on the cell surface. To investigate whether the homodimers are present in original tumors, the expression of the c-Ret protein was analyzed in eight sporadic and two MEN 2A-associated pheochromocytomas, the latter two of which contained mutations in cysteine 618 or 634 of Ret. The c-Ret protein was expressed at variable levels in all pheochromocytomas examined. By labeling the c-Ret protein immunoprecipitated from tumor tissues with [gamma-32P]ATP in vitro, its homodimers were detected in pheochromocytomas from MEN 2A patients but not in a sporadic tumor. This result represents the first demonstration of Ret homodimers in original tumors.

Drosophila Proteins↗
PubMed1996

Suppressive effect of iodine on DMBA-induced breast tumor growth in the rat.

Concerning the suppressive effect of inorganic iodine on the growth of 7,12-dimethyl-benz(a)anthracene (DMBA)-induced breast tumor in female Sprague-Dawley (SD) rats, we previously reported that although iodine itself had a suppressive effect on the tumor growth, its effect was not as strong as that of MPA (medroxy-progesterone acetate). However, the combined medication of iodine at a low concentration + MPA showed a stronger effect than MPA alone. The purpose of the present study is to elucidate this mechanism of action by determining the uptake of the administered iodine into breast tumor tissue. Breast tumors were induced with DMBA in female SD rats, and these animals were treated with MPA + inorganic iodine at various concentrations for 4 weeks to determine tumor growth and tumor iodine content. In the comparison of tissue iodine content in growth-suppressive tumors with that in nonsuppressive tumors, the former showed a much higher iodine content. This suggests that direct uptake of inorganic iodine by breast tumors led to the suppression of tumor growth.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1996

Different metastatic potentials of ras- and src-transformed BALB/c 3T3 A31 variant cells.

The metastatic phenotype of tumor cells is thought to be induced by an aberrant signaling cascade or cascades that are different from those required for tumorigenicity. Oncogene-transfected cells with different tumorigenicities and metastatic potentials have been used to identify such pathways and responsible molecules. However, oncogenes that can induce tumorigenicity in recipient cells also frequently induce the metastatic phenotype at the same time. The difficulty in obtaining cell lines that are tumorigenic but not metastatic has hampered such studies. In this report, we transfected the activated c-Ha-ras oncogene into BALB/c 3T3 A31 variant cells and found that the transfectants were tumorigenic but they did not form metastatic lung modules in the experimental metastasis assay. The phenotype was very stable and was maintained during cultivation. On the other hand, the metastatic potentials of either the transfected cells or the original variant cells could be induced by transfection of the v-src oncogene. The src transfectants formed extensive nodules in lung when injected into the tail veins of congeneric mice. The cell motility of the metastatic src transfectants on Matrigel-coated dishes was greater than that of the ras transfectants. The src transfectants were also invasive in Matrigel when analyzed on a filter. These variant cells transformed by the ras and src oncogenes will be a useful system for identifying the signaling cascades responsible for the metastatic potential of tumors.

3T3 Cells↗
PubMed1996

Interrelationship of day length and temperature on the control of gonadal development, body mass, and fat score in white-crowned sparrows, Zonotrichia leucophrys gambelii.

We tested the effects of naturally relevant environmental temperatures on long day-induced reproductive development in male and female white-crowned sparrows, Zonotrichia leucophrys gambelii. Transfer from short days (8L 16D) to long days (20L 4D) resulted in rapid testicular development and partial ovarian development as has been reported many times previously. Exposure of experimental groups to low (5 degrees), moderate (20 degrees), and high (30 degrees) temperature during photostimulation had only subtle effects on plasma levels of follicle-stimulating hormone and luteinizing hormone over time and no effects on the size of testes, cloacal protuberance, ovaries, or brood patch at Day 30 of treatment. Long days resulted in the well known increase in body mass and fat score, indicative of preparations for migration. In females, treatment with low temperature resulted in a reduction in the premigratory increase in fat and body mass when transferred to long days. This was accompanied by an increase in plasma levels of corticosterone during the early stages of photostimulation at low temperature. Temperature regimes had no effects on fattening or body mass in males, despite an early increase in plasma corticosterone at low temperature. Circulating levels of thyroxine (T4) and triiodothyronine (T3) increased to varying degrees following photostimulation. Temperature treatment had no effect on plasma levels of thyroid hormones in males, but low temperature did inhibit thyroid hormone secretion (particularly T4) in females. Although reproductive development appears to be resistant to naturally relevant temperature extremes in both sexes, low environmental temperature impaired preparations for migration in females but not males. This effect may be mediated through glucocorticosteroids and not thyroid hormones. Reasons for the sexual dimorphism in this response are unknown, but may be related to sexual selection for males to arrive on the breeding grounds ahead of females regardless of local weather conditions.

Adipose Tissue↗
PubMed1996

Integrative transformation of the zygomycete Rhizomucor pusillus by homologous recombination.

For development of a homologous transformation system for the zygomycete fungus, Rhizomucor pusillus, the isopropylmalate isomerase (leuA) gene was cloned from R. pusillus IFO 4578 by the DNA-probing method with the leuA sequence of Mucor circinelloides as probe. The nucleotide sequence revealed that leuA of R. pusillus encoded a 755-amino-acid protein of 82.5 kDa with no intron. The leuA gene on pUC19 (plasmid pRPLeu10) was introduced by polyethyleneglycol-assisted transformation into protoplasts of a leuA- mutant of R. pusillus that was obtained by UV mutagenesis. Transformation under optimal conditions yielded 20 Leu+ transformants (micrograms pRPLeu10 DNA)-1 (1 x 10(6) viable protoplasts)-1. Blot analysis of DNA from the transformants showed that the pRPLeu10 sequence was integrated into the genome by homologous recombination at the leuA locus.

Amino Acid Sequence↗
PubMed1996

Adrenalectomy for treatment of Cushing syndrome: results in 122 patients and long-term follow-up studies.

Patients with Cushing syndrome (n = 122) who underwent adrenalectomy from 1957 through 1993 were reviewed for survival and complications. Of the 122 patients, 70 had adrenocortical adenoma, 30 Cushing's disease, 6 primary pigmented nodular adrenocortical disease (PPNAD), 7 other types of primary nodular hyperplasia, 5 adrenocortical carcinoma, and 4 ectopic ACTH syndrome. Sixty-five patients with adrenocortical adenoma are alive, and the survival rate was equal to the age-matched control population, when patients who died of the postoperative complication were excluded. Of the patients with Cushing's disease, 20 are alive; and 10 of 16 patients (63%) who were followed-up and evaluated had skin pigmentation. Four of sixteen patients (25%) developed Nelson's syndrome. Four PPNAD patients and five with other types of nodular hyperplasia are alive. Most of these patients underwent bilateral total adrenalectomy, but some patients remitted after unilateral adrenalectomy. All of five adrenocortical carcinoma patients and four with ectopic ACTH syndrome died within 2 years after operation. The prognosis for patients with adrenocortical adenoma after unilateral adrenalectomy is excellent, though it is important to avoid operative complications. The rapid cure of signs and symptoms of glucocorticoid excess after total adrenalectomy is ensured, and prognosis is satisfactory under careful glucocorticoid replacement, making total adrenalectomy an alternative treatment for Cushing's disease.

ACTH Syndrome, Ectopic↗
PubMed1996

Development of relative power contribution ratio of the EEG in normal children: a multivariate autoregressive modeling approach.

The relative power contribution ratio using a multivariate autoregressive model was applied to determine the spread of delta, theta, alpha and beta activity over the scalp in childhood. EEGs of 264 normal healthy subjects from 3 to 26 years were recorded from Fp1, Fp2, C3, C4, O1 and O2 with linked ears during the resting relaxed state with eyes closed. After selecting the epoch to remove artifacts, the relative power contribution ratio at each frequency band was calculated from the digitized EEG. The most noticeable developmental change was seen in the alpha frequency, where the relative power contribution ratio from its own area decreased significantly with age, and ratios from the other areas increased significantly. The change was larger at the frontal and smaller at the occipital region. Consequently, the occipital alpha wave was stable after 3 years of age. Developmental change at beta frequency was similar to alpha activity, but the number of components with significant change was smaller at delta and theta frequencies. Thus the relative power contribution of the EEG enabled us to observe how relationships among each location of EEG matured.

Adolescent↗
PubMed1996

Changes in striatal dopamine release in stress-induced conditioned suppression of motility in rats.

Rats received a footshock for 10 min in a chamber with a metallic grid floor, and then placed into the chamber for 30 min after 6 days. The motility of the shocked rats showed a significant decrease (conditioned suppression of motility). In addition, the extracellular dopamine (DA) levels in the striatum were also reduced significantly in in vivo microdialysis study. Thus, dysfunction in the striatal DAergic neuronal systems is responsible for mental stress responses such as conditioned fear stress.

Animals↗
PubMed1996

Subcloning of three osteoblastic cell lines with distinct differentiation phenotypes from the mouse osteoblastic cell line KS-4.

Three distinct osteoblastic cell lines (KS418, KS460, and KS483) were subcloned from the mouse osteoblastic KS-4 cells, which possessed the abilities not only to differentiate into mature osteoblasts, but also to support osteoclast differentiation in coculture with spleen cells. The order of the magnitude of the basal alkaline phosphatase (ALP) activity was KS483 > KS418 > KS460. KS483 cells were also more differentiated than KS418 and KS460 in terms of ALP activity and osteocalcin production, when cultured in growth medium containing 10% fetal bovine serum. In long-term culture, KS418 and KS483 apparently differentiated into mature osteoblasts and formed calcified nodules without addition of beta-glycerophosphate. Electron microscopic analysis demonstrated that calcification occurring in the nodules was initiated in the matrix vesicles as observed in bone formation in vivo. Nodule formation and mineral deposition occurred simultaneously in the presence of beta-glycerophosphate, but the former always preceded the latter without addition of beta-glycerophosphate. In contrast, KS460 cells did not show time-dependent increases of ALP activity, type I collagen expression and osteocalcin production, which were induced by treatment with recombinant osteogenic protein-1 (OP-1). The three cell lines similarly supported osteoclast differentiation in coculture with spleen cells in response to 1,25-dihydroxyvitamin D3. These results indicate that the three cell lines subcloned from the original KS-4 cells represent phenotypically distinct osteoblasts during osteoblast differentiation, but are equipped similarly with the capacity to support osteoclast differentiation. The subcloned cells of the KS-4 series may provide useful systems in which to study osteoblast differentiation and function.

Actins↗
PubMed1996

Knee laxity in patients with osteoarthritis and rheumatoid arthritis.

Thirty-four patients with osteoarthritis (OA) and 32 patients with rheumatoid arthritis (RA) were studied to determine the effects of OA and RA on the laxity of the knee joints. Laxity was measured with the Genucom Knee Analysis System. The antero-posterior laxity of the OA and RA knees was greater than the control, normal knees in the early stage, and decreased with the severity of disease in OA, but not in RA. Severe OA and RA were associated with a restricted internal-external rotation at the knee joint compared with the control. Internal-external rotation decreased with worsening of both diseases. Varus-valgus laxity tended to increase slightly with the severity of disease. While the morphological changes of the cruciate ligaments in advanced OA and RA were not statistically different, the laxity of OA-afflicted knees was affected slightly by the severity of the damage to the cruciate ligaments.

Adult↗
PubMed1996

Overexpression of multidrug resistance protein gene in human cancer cell lines selected for drug resistance to epipodophyllotoxins.

Overexpression of either the multidrug resistance 1 (MDR1) gene or multidrug resistance protein (MRP) gene is involved in acquisition of multidrug-resistant phenotypes in human cancer cells. In this study we examined whether selection for resistance to the epipodophyllotoxins, etoposide/teniposide (VP16/VM26), could induce overexpression of MDR1 or MRP. We have previously isolated two VP16/VM26-resistant KB cell lines. Two VP16/VM26-resistant KB cell lines, KB/VM-1 and KB/ VM-4, which were selected by stepwise exposure to VM26 had decreased accumulation of [3H]VP16 and increased levels of MRP, but no apparent expression of MDR1 gene was observed. Another VP16/VM26-resistant KB cell line, KB/VP-4, which was further isolated from a VP16-resistant KB cell line, KB/VP-2, had decreased accumulation of [3H]VP16 and showed overexpression of MRP gene, but not that of MDR1 gene. We also isolated a VP16-resistant cell line, IN157/VP-1, from a human glioma cell line IN157. IN157/VP-1 cells showed decreased accumulation of [3H]VP16 and overexpression of MRP gene, but not of MDR1. These findings suggest that selection for resistance to VP16/VM26, preferentially induces overexpression of MRP gene.

ATP-Binding Cassette Transporters↗
PubMed1996

Expression of hybrid isomyosins in human skeletal muscle.

Myosin of human skeletal muscles was analyzed by means of several electrophoretic techniques. Myosin heavy chain (HC)-IIa-and HC-IIb-based isomyosins were identified by pyrophosphate-polyacrylamide gel electrophoresis (PP-PAGE). The electrophoretic mobilities of these fast-twitch muscle isomyosins differed in the order HC-IIa triplets < HC-IIb triplets. To determine the subunit composition of myosin molecules that function in intact muscle, two-dimensional electrophoresis in which the first and second dimensions were PP-PAGE and sodium dodecyl sulfate-PAGE, respectively, was also performed. Slow-twitch muscle isomyosin contained, in addition to slow-twitch light chain (LC) and HC-I isoforms, appreciable amounts of LC-2f, HC-IIa, and HC-IIb isoforms, and fast-twitch muscle isomyosin consisted of LC-2s and HC-I isoforms as well as fast-twitch LC and HC isoforms. Without consideration of HC- and slow-twitch alkali LC heterodimers, at least 31 possible isomyosins are derived from these findings on the subunit composition of isomyosins in human skeletal muscle.

Diphosphates↗
PubMed1996

Immunohistochemical localization of activin A and follistatin in human tissues.

We immunohistochemically investigated the localization of activin A and follistatin in various human tissues with specific antibodies to recombinant human (rh-) activin A and rh-follistatin. Specific immunostaining of activin A was detected in Leydig and Sertoli cells of the testis. In the ovary, granulosa cells of mature follicle and luteal cells of the corpus luteum stained for activin A. Immunoreactive activin A was present in somatotrophs of the pituitary gland and insulin-positive B cells of the pancreatic islets. Immunoreactivity for activin A was also found in thyroid follicular cells, adrenocortical cells, neuronal cells of the cerebrum and monocytoid cells in the bone marrow. Follistatin, an activin-binding protein, was immunostained in the same tissues as activin A. These findings indicated that activin A and follistatin are widely distributed in human tissues, suggesting that activin plays important roles as a common regulator in various tissues under the control of co-existing follistatin.

Activins↗
PubMed1996

A case report of an elderly patient with acromegaly.

We encountered a 91-year-old patient with acromegalic features. The serum levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I) were increased to 23.3 ng/ml and to 268 ng/ml, respectively. Both thyrotropin-releasing hormone and luteinizing hormone-releasing hormone tests demonstrated a 2-3 fold increase in the serum GH level. Magnetic resonance imaging disclosed a pituitary mass in the enlarged sella. The patient was diagnosed as having acromegaly due to overproduction of GH from a pituitary tumor. She manifested cardiac hypertrophy with severe aortic stenosis and mild hypertension, but without diabetes mellitus. After the administration of octreotide subcutaneously at a dose of 25 to 50 micrograms daily for 20 days, the serum GH level increased transiently but decreased rapidly to approximately half the initial level, and suppression of the GH level persisted thereafter for over 2.5 months. This patient seems to be the oldest patient with acromegaly among those reported in Japan.

Acromegaly↗
PubMed1996

Incidentally discovered adrenocortical adenomas are not fully nonfunctioning: immunohistochemical and dispersed adrenocortical cell study.

To clarify the precise function of incidentally discovered adrenocortical adenoma, immunohistochemical and dispersed adrenal cell studies were performed. We have recently seen five patients with so-called nonfunctioning adrenocortical adenoma. Diurnal variation in plasma cortisol and suppression of plasma cortisol and urine 17-hydroxycorticosteroids in response to dexamethasone administration revealed adrenocortical function within normal limits in all cases, and no signs or symptoms of adrenal steroid hormone excess were evident. Since a high uptake of iodomethylnorcholesterol was recognized in each adrenal mass, it was supposed that these adrenal tumors produced steroid hormone to a certain extent, and each patient received unilateral adrenalectomy. P450c17, a key enzyme involved in cortisol production, was expressed in the tumor region in all cases in an immunohistochemical study. Upon in vitro steroidogenesis with dispersed adrenal cells in two cases, all steroid hormones measured except for aldosterone (progesterone, 17 alpha-hydroxyprogesterone, pregnenolone, 17 alpha-hydroxypregnenolone, 11-deoxycortisol, cortisol, 11-deoxycorticosterone, corticosterone, 18-hydroxydeoxycorticosterone, dehydroepiandrosterone and androstenedione) were produced in a culture medium. The results indicated that these tumors possessed the capacity for cortisol production, which was in agreement with the results of an iodomethyl-norcholesterol scintigraphy. All patients with mild hypertension or diabetes mellitus had no signs or symptoms of steroid hormone excess, but they could potentially develop a steroid excess syndrome such as Cushing's syndrome in the future.

17-Hydroxycorticosteroids↗
PubMed1996

Magnetic resonance imaging of brain death.

Fifteen patients with clinical diagnosis of brain death were examined by magnetic resonance (MR) imaging. Aortography with intraarterial digital subtraction angiography (IADSA) was also performed in nine patients. MR imaging indications of the flow void phenomenon were evaluated in the cavernous portion of internal carotid artery (ICA) and the middle or anterior cerebral artery, and compared with the IADSA findings. The relative intensities of gray and white matters were also measured. MR imaging showed that flow voids were absent in the ICA in all eight patients in whom non-filling was confirmed by IADSA. In one patient, IADSA demonstrated intracranial flow despite the diagnosis of brain death and the flow void pattern was normal. Serial MR imaging showed disappearance or abnormality of flow voids after brain death in six patients and absence before brain death in one. Spotty flow voids became visible in the unilateral ICA of one case after brain death. Partial residual flow voids may be caused by to-and-fro blood movement which was demonstrated by transcranial Doppler sonography. The normal flow void pattern was seen in none of these patients, therefore absence of flow voids indicates cessation of intracranial blood flow. Proton density and T2-weighted MR images showed dissociated intensity changes between white and gray matters, which were thought to be characteristic of brain death. In conclusion, MR imaging can achieve non-invasive diagnosis of the non-filling phenomenon in patients with brain death.

Adult↗
PubMed1996

Treatment of large radicular cysts by modified marsupialization.

We describe the enucleation of large radicular cysts to the maximum extent, and their treatment based on the concept of marsupialization and drainage after apicoectomy. Marsupialization requires a long period for healing, imposing a burden on the patient with regard to postoperative management. Considering this, together with the difficulty involved in the clinical diagnosis of radicular cysts, curettage of the cyst wall and drainage may be more effective for facilitating the healing process than use of marsupialization alone.

Adult↗