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Biomedical subjects

Y Yamane

Publications and source records attributed to Y Yamane.

At least 199 records · Page 11Linked to original sources
PubMed1989

The thallium-201 time activity curve in thyroid cancer: a role for the detection of metastases.

The Tl-201 Cl time activity curves were evaluated in 17 patients with histologically proven benign nodules and papillary carcinoma of the thyroid gland. In the dynamic studies, the uptake at the region of interest was counted every 10 sec for 20 min after the intravenous injection of 2mCi Tl-201 Cl. The curves from frame 21 to 100 were transformed to linear plots for clinical evaluation. Papillary carcinoma could not be differentiated from benign lesions by means of the values of the washout rate. However, the "relative washout rate" in papillary carcinoma was lower than that of benign lesions (P less than 0.05). Although the average values of the "relative extrapolated uptake" in papillary carcinoma appeared to be greater than those in benign lesions, the difference was not statistically significant. The difference in the washout rates between lymph node metastases and local recurrences, and pulmonary metastases of the papillary carcinoma was significant (P less than 0.05).

Adenoma↗
PubMed1989

In vitro study on the corrosion behavior of three commercial Ag-Pd-Cu-Au alloys in Ringer's and 0.1%Na2S solutions.

The corrosion resistance of three commercial Ag-Pd-Cu-Au alloys was estimated in Ringer's and 0.1% Na2S solutions by electrochemical techniques and surface analyses. In Ringer's solution, the three alloys showed high corrosion resistance and there was no significant difference in the anodic polarization characteristics of the three alloys. In the 0.1% Na2S solution, the Alloy A which had the lowest noble metal content (Au + Pd) exhibited the highest anodic reactivity with the largest amount of corrosion product on the alloy surface. It was determined that the Ag-rich phase of Ag-Pd-Cu-Au alloy was preferentially attacked to form Ag2S corrosion product. The polarization resistance data showed that the corrosion rate for Alloy A in 0.1% Na2S solution was determined to be 500 times higher than that in Ringer's solution. The corrosion rate of the alloy in the freely corroded condition can be estimated quantitatively and precisely by measuring the polarization resistance.

Copper↗
PubMed1989

Platelet vasopressin receptor in patients with chronic renal failure.

The vasopressin binding to intact platelet from patients with chronic renal failure (CRF) was investigated in relation to the abnormalities in platelet aggregation. The immunoreactive arginine vasopressin (AVP) in platelet-free plasma (PFP) but not in platelets was significantly higher in non-dialyzed patients with CRF than in normal subjects. Binding studies using [3H]AVP demonstrated a decreased number of binding sites (Bmax) on platelets from patients with CRF compared to normal controls with no significant difference in affinity (Ka). A significant diminution of the maximal percentage aggregation with AVP was found in patients with CRF. An inverse relation between Bmax and the PFP AVP levels and a highly significant relation between Bmax and the maximal percentage aggregation with AVP in patients with CRF and normal controls were observed. At 4 weeks after the introduction of hemodialysis in patients with CRF, the PFP AVP levels decreased and Bmax increased significantly, and the maximal percentage aggregation tended to increase. The present findings suggest that a reduced number of AVP receptors on platelets might account for decreased platelet aggregation with AVP, and the elevated plasma AVP levels might induce a down-regulation of the AVP receptor number on platelets in patients with CRF.

Adult↗
PubMed1989

[Porphyria cutanea tarda in a chronic hemodialysis patient].

About 3 years after commencing hemodialysis for chronic renal failure, a 39-year-old man developed cutaneous lesions of the face and hands which were compatible with porphyria cutanea tarda (PCT) clinically and histologically. There was no evidence of familial PCT, excessive alcohol consumption, iron overload, chronic liver disease. It was impossible to measure urinary porphyrins because of anuria. Fecal and erythrocytic porphyrins were within normal limits. Plasma porphyrins, however, were markedly elevated, and in an assay using high performance liquid chromatography, uroporphyrin accounted for 72% and 7-carboxyl porphyrin for 24%. Review of past reports of PCT associated with hemodialysis revealed that the most characteristic feature was a significant increase of plasma porphyrins, mainly uroporphyrin. This increase is difficult to explain by accumulation due to failure of adequate clearance. Participation of factors affecting uroporphyrinogen decarboxylase activity seems likely.

Adult↗
PubMed1989

Prognostic potential of serum CA125 and pregnant markers in threatened abortion.

To predict the outcome of patients with threatened abortion at an early stage of gestation is clinically important. CA125 and nine hormones associated with pregnancy were measured from 4 to 12 weeks of gestation in 256 pregnant women with threatened abortion. The nine hormones were: serum human chorionic gonadotropin beta-subunit, serum progesterone, serum cortisol, serum human placental lactogen, serum estrone, serum estradiol, serum estriol, urine human chorionic gonadotropin and urine estrogen. Ultrasonographic examination was also performed from 6 to 12 weeks of gestation. Of the 256 patients, 90 aborted and 166 carried to term. We found that changes in CA125 in patients with threatened abortion differed from those of the nine hormones. At 4 to 8 weeks of gestation the mean value for serum CA125 in patients with successful outcome was significantly higher than that in patients who aborted. Although ultrasonographic examination is effective after 8 weeks of gestation, serum CA125 measurement is useful in predicting early abortion.

Abortion, Threatened↗
PubMed1989

[A human infection of the cestode, Diphyllobothrium nihonkaiense Yamane et al., 1986].

A mature cestode, obtained from a 49-year-old man in Fukuoka, southern Japan, was examined. The worm was about 70 cm in length without scolex. The largest segment was 1.8 x 0.8 cm. Cirrus sac lay at an obtuse angle (about 150 degrees) to seminal vesicle. The eggs were 62.06 +/- 9.40 x 43.33 +/- 6.43 microns and the shell thickness 1.0-1.5 microns, with round, shallow and sparsely distributed surface pits ranging 0.8-2.0 microns in diameter. The above features suggested that this worm was identified as the cestode, Diphyllobothrium nihonkaiense.

Animals↗
PubMed1988

Heart with circulatory failure secretes and processes atrial natriuretic peptide in a manner different from normal heart.

The role of catecholamine in atrial natriuretic peptide (ANP) secretion and its secretory mechanism in normal humans is not well defined; therefore, we studied the relationship among ANP, catecholamine, and atrial pressures in 25 patients without cardiovascular disease and in 35 patients with chronic congestive heart failure (CHF, 20 in mitral valve disease and 15 in dilated cardiomyopathy). In patients without cardiovascular disease, right atrial pressure at rest showed a positive correlation (r = 0.80, p less than 0.001) with ANP concentration, whereas left atrial pressure did not. The relation narrowed (r = 0.82) when the bicycle ergometer exercise in the supine position was conducted. Neither adrenalin nor noradrenalin significantly correlated with ANP concentration. In patients with mitral valve disease and dilated cardiomyopathy, the significant relations (r = 0.56 p less than 0.001, r = 0.85 p less than 0.001, respectively) between left atrial pressures and ANP concentrations at rest were observed, and following exercise, induced more significant relations. Right atrial pressures did not correlate positively with ANP concentrations. The increments of ANP concentrations induced by exercise load were markedly reduced compared with those of patients without cardiovascular disease. Although concentrations of both noradrenalin and adrenalin in patients with mitral valve disease and dilated cardiomyopathy at rest were much higher than those without cardiovascular disease, only noradrenalin had a highly positive correlation with ANP concentrations (r = 0.88 p less than 0.001, r = 0.78 p less than 0.001, respectively). Furthermore, the circulating ANP molecular weight forms in all patients studied were analyzed by gel chromatography coupled with radioimmunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Early development of four Diphyllobothrium species in the final host.

The early development of four Diphyllobothrium species, D. latum, D. dendriticum, D. ditremum, and D. vogeli, are described. D. latum sheds the entire larval body easily and shows a high shedding rate of 82.1% on average. On the other hand, D. dendriticum exhibits a different developmental pattern, with a low shedding rate of 8.7% in the hamster and a high shedding rate of 34.9% in the rat. D. ditremum is difficult to recover from hamsters but shows a high shedding rate of 42.9%. D. vogeli shows a constant recovery rate of 38.3% without shedding. The species specificity of these four diphyllobothriids is discussed briefly in relation to the early developmental pattern and the growth rate.

Animals↗
PubMed1988

Protective effect of sodium molybdate on the acute toxicity of mercuric chloride. V. Enhancement of renal regeneration after exposure to HgCl2.

Pretreatment with Na2MoO4 protected rats from HgCl2-induced decreases in the renal concentration of amino acids, RNA, DNA, ATP and dry matter. It also reduced the mercury-induced increases in renal water, Ca and serum creatinine. Ma2MoO4 considerably elevated the RNA/DNA ratio in the renal cortex after treatment with HgCl2. In addition, subcellular distribution of mercury was markedly altered by pretreatment with Na2MoO4, specifically Na2MoO4 pretreatment decreased the mercury content in the particulate fractions such as the nuclei and mitochondria while increasing the mercury content of the cytosol. Sephadex G-75 gel filtration showed that the increase in mercury content in the cytosol of Na2MoO4-pretreated rats is due to an increase in the metal content of a metallothionein-like fraction. These results suggest that Na2MoO4-pretreatment protects against HgCl2 renal toxicity by stimulating mercury-mediated metallothionein induction in the renal cortex and renal regenerative processes.

Adenosine Triphosphate↗
PubMed1988

Platelet vasopressin receptor in essential hypertension.

The specific vasopressin receptor of V1 vascular subtype, which mediates platelet aggregation, has been found on human platelets. We investigated the binding characteristics using tritiated arginine vasopressin [3H]-AVP and platelet aggregation with AVP turbidometrically in normal subjects, patients with WHO class II essential hypertension and patients with malignant-phase hypertension. In essential hypertensives Bmax was significantly higher than that in normal subjects, but there were no differences in affinity and the maximal percentage aggregation between them. In malignant-phase hypertensives Bmax and maximal percentage aggregation were significantly lower than those in normals and essential hypertensives, although there was no difference in the affinity between them. With radio-immunoassay, the mean platelet-free plasma AVP level was significantly higher in malignant-phase hypertensives than those in normals and essential hypertensives, whereas there was no difference in mean platelet AVP levels between them. In essential hypertensives Bmax and maximal percentage aggregation did not change, but in malignant-phase hypertensives Bmax increased significantly and maximal percentage aggregation tended to normalize after treatment.

Arginine Vasopressin↗
PubMed1988

Characterization of human platelet vasopressin receptor and the relation between vasopressin-induced platelet aggregation and vasopressin binding to platelets.

Immunoreactive AVP was found to be much higher in platelets than in platelet-free plasma (PFP) in normal subjects (12.8 +/- 6.3 versus 1.7 +/- 0.8 fmol/ml). AVP levels in PFP were appreciably elevated in parallel with the elevation of plasma osmolality induced by the acute osmotic stimulation, while the AVP levels in platelets did not change before and after the stimulation. Binding studies on intact platelets demonstrated specific binding sites for [3H]AVP. The specific binding was time, temperature and concentration-dependent, saturable and reversible, with the maximal binding capacity (Bmax) of 169.9 +/- 14.4 sites/platelet and affinity of 4.84 +/- 1.15 x 10(8)M-1. The affinity constants for unlabelled AVP, lysine vasopressin (LVP), oxytocin (OT) and dDAVP were 9.0, 8.5, 7.4 and 6.6, respectively, and the inhibition constant for d(CH2)5Tyr(Me)AVP (V1-antagonist) was 7.7. There was a highly significant correlation between the affinity constants of AVP analogues and their relative vasopressor activities in vivo, whereas no such correlation was found between the affinity constants and antidiuretic activities. AVP caused platelet aggregation with the maximal aggregation of 48.0 +/- 25.1% at 230 nM of AVP. A significant correlation was observed between the maximal percentage aggregation and Bmax of [3H]AVP to intact platelets. These results suggest that the platelet vasopressin receptor belongs to the V1 vascular subtype and mediates platelet aggregation.

Adult↗
PubMed1988

Role of calcium and protein kinase C in ANP secretion by cultured rat cardiocytes.

The secretory mechanism of rat atrial natriuretic peptide (rANP) was studied in vitro with the use of primary culture of atrial myocytes from neonatal rats. Norepinephrine, phenylephrine, and carbamylcholine stimulated immunoreactive (IR) rANP secretion, whereas neither angiotensin II, arginine vasopressin, nor isoproterenol affected its secretion. The stimulatory effects of carbamylcholine and phenylephrine were blocked by atropine and prazosin, respectively. 12-O-tetradecanoylphorbol-beta-acetate (TPA), protein kinase C activator, induced a dose-dependent increase in IR rANP secretion, and TPA combined with Ca2+ ionophore ionomycin produced a synergistic effect. Ca2+-channel agonist BAY K 8644 also stimulated IR rANP secretion, the effect of which was blocked by Ca2+-channel antagonist nifedipine. These data suggest that alpha 1-adrenergic and muscarinic cholinergic agonists have direct action on rat cardiocytes to stimulate ANP secretion that involves receptor-mediated mobilization of intracellular Ca2+ and activation of protein kinase C.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗