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Biomedical subjects

Y Yoshimoto

Publications and source records attributed to Y Yoshimoto.

At least 163 records · Page 9Linked to original sources
PubMed1986

[Obstetric factors associated with intracranial hemorrhage (ICH) in premature infants and antenatal prediction of ICH].

Obstetric factors associated with intracranial hemorrhage (ICH) were evaluated in 98 inborn premature infants of less than 1,500 gm birth weight or less than 32 weeks of gestation. ICH was detected in 25 (25.5%) of these infants by ultrasound sonography and/or computed tomography. No association of obstetric factors such as maternal age, parity, gravidity, premature rupture of the membrane, toxemia, placenta previa, fetal position, mode of delivery or fetal sex with ICH was noted. But the ICH group showed a higher incidence of placental abruption, infarction, infection and incompetent cervix than the non-ICH group. In addition, gestational ages and birth weights were less in the ICH group than in the non-ICH group, although differences were not significant except for the group with incompetent cervix (p less than 0.05). However, Apgar scores and FHR scores according to Krebs et al. for the ICH group were significantly lower than those for the non-ICH group. The two groups were distinguished by multivariable discriminant analysis of FHR scores, birth weights and gestational ages (discriminant efficiency, 3.74: F-value, 20.6: true positive ratio, 81.3%). These results suggested that antenatal prediction of ICH in premature infants was possible, but further studies are needed to elucidate the reliability of its prediction.

Adult↗
PubMed1985

Additive effects of parathyroid hormone and calcitonin on adenosine 3',5'-monophosphate release in newly established perfusion system of rat femur.

A new perfusion system of isolated rat femora was established, and the effect of PTH or calcitonin (CT) on cAMP release from the adult bone was examined. Stimulation of cAMP release from the isolated perfused bone peaked rapidly between 5 and 10 min after human PTH (hPTH)-(1-34) or eel CT injection, respectively, and declined gradually toward the preinjection level. However CT exhibited a longer lived effect than PTH. Release of cAMP was still significantly greater than control at 60 min after a bolus injection of CT. The rate of cAMP release was directly related to the dose of PTH or CT. H2O2-oxidized PTH (biologically inactive) caused no increase in cAMP release. hPTH-(1-34) was markedly more potent than hPTH-(1-84) in stimulating cAMP release from the perfused bone on an equimolar basis. Simultaneous administration of 5 micrograms PTH and 5 micrograms CT at maximal stimulatory doses produced additive effects, indicating the presence of separate receptor sites for PTH and CT in the bone. In conclusion, this system provides us a means by which hormone actions on adult bone with integrity of the organ can be evaluated and therefore makes possible systemic investigation of the osteoblast-osteoclast function.

Animals↗
PubMed1985

Cleavage in a saponin model of the sea urchin egg.

A cell model, in which cleavage could be induced, was obtained from fertilized sea urchin eggs by putting eggs that were in the first cleavage into a solution containing 3 X 10(-5) g/ml saponin and suitable amounts of ATP and Ca2+. The cell membrane became freely permeable to ATP and Ca2+ within 1 minute. The respective optimal concentrations of ATP and Ca2+ that advanced the cleavage furrow in this model were 2 mM and 10(-8) M. With the optimal ATP and Ca2+ concentrations, the cleavage furrow of the model advanced at a rate that differed little from that in living eggs. The cleavage furrow soon receded, however, when the concentration of ATP was decreased to less than 1 mM or increased to more than 3 mM, as well as when the concentration of Ca2+ was increased to more than 10(-7) M.

Adenosine Triphosphate↗
PubMed1985

[Stimulatory effect of a traditional herbal medicine, Unkeito on LH-RH release].

In order to study the effect of Unkeito (Chinese name, Wen-Jan-Tang), a traditional Chinese herbal medicine and its components on luteinizing hormone-releasing hormone (LH-RH) and LH release, the mediobasal hypothalamus (MBH) alone or the pituitary alone or the pituitary in sequence with the MBH from normal female rats in diestrus was perifused in a sequential double-chamber perifusion system. LH-RH release from MBH increased significantly (p less than 0.05) by 50-100% of the basal level 30-90 min after the beginning of Unkeito administration. Unkeito at 5 micrograms/ml induced significant LH release (60-95% increase) from the pituitary in series with the MBH, but had no effect on LH release from the pituitary perifused alone. One of Unkeito's components Botanpi induced significant LH release, although other five components had no effect on LH release. These data suggest that Unkeito induces LH release from the pituitary through hypothalamic LH-RH, and can be used for the treatment of patients with hypothalamic amenorrhea.

Animals↗
PubMed1984

[Urinary phosphate and cyclic adenosine monophosphate response to intravenous administration of synthetic human parathyroid hormone-(1-34) in idiopathic hypoparathyroidism, pseudohypoparathyroidism, pseudopseudohypoparathyroidism and normal subjects].

The response to exogenous parathyroid hormone (PTH) with urinary excretion of phosphate and cyclic adenosine monophosphate (cAMP) was tested by the use of synthetic human parathyroid hormone (1-34) [hPTH-(1-34)] on 59 patients with hypocalcemia and normal or high serum inorganic phosphorus and normal renal function without a history of parathyroidectomy for differentiation between idiopathic hypoparathyroidism (IHP), pseudohypoparathyroidism (PHP) and related diseases along with 18 normal subjects. A positive phosphaturic response to exogenous PTH was defined as the increment of 2 hours phosphate excretion (delta P) of more than 35 mg. A positive urinary cAMP response to exogenous PTH was defined as the increment by more than 1 mumole per one hour (delta cAMP) and the increase of 1 hour excretion by more than 10 times. Increments of 2 hours urinary phosphate excretion in response to hPTH-(1-34) 100 units were 60.5 +/- 7.7 mg (mean +/- SEM) in 27 patients with IHP, 23.5 +/- 5.9 mg in 21 patients with PHP type I and 24.9 +/- 4.0 mg in 17 normal subjects. Increments of 1 hour urinary cAMP excretion in response to hPTH-(1-34) 100 units were 12.0 +/- 1.5 mumole in 27 patients with IHP, 0.33 +/- 0.10 mumole in patients with PHP type I and 23.6 +/- 5.8 mumole in 15 normal subjects. Ratios of 1 hour urinary cAMP excretion were 97 +/- 10 in 27 patients with IHP, 3.6 +/- 0.5 in 21 patients with PHP type I and 54 +/- 14 in 15 normal subjects. Positive phosphaturic and negative urinary cAMP response was encountered in 3 out of 21 patients with PHP type I in response to hPTH-(1-34). This exaggerated phosphaturic response should be considered as due to the influence of treatment with Ca or vitamin D derivatives.

Adolescent↗
PubMed1984

Calcium transport in perfused duodena from normal chicks: enhancement within fourteen minutes of exposure to 1,25-dihydroxyvitamin D3.

The effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3) on calcium transport was studied in vascularly perfused duodena of normal, vitamin D-replete chicks. Addition of 130 pM 1,25(OH)2D3 to the perfusate resulted in a significant increase in 45Ca transport from the lumen to the vascular effluent within 14 min; the transport rate rose to 140% of levels in comparable preparations exposed for 40 min to vehicle. No effects of 1,25(OH)2D3 were noted on the back flux or transfer of 45Ca from the vascular effluent to the lumen. Vascular perfusion with 100 microM colchicine, an antimicrotubular agent, abolished the rapid lumen-to-vascular effluent effect of 1,25(OH)2D3 on 45Ca transport, relative to preparations exposed to the secosteroid and 100 microM lumicolchicine, (a light inactivated analog of colchicine). Colchicine did not, however, alter basal 45Ca transport rates. Addition of 130 pM 1,25(OH)2D3 to the lumenal compartment of normal chicks or vascular perfusion of duodena from vitamin D-deficient birds failed to increase 45Ca transport above control levels. Perfusion of duodena from normal chicks with 650 pM 1,25(OH)2D3 further increased calcium transport to 170% of levels observed in preparations treated with 130 pM steroid, and 210% of levels in controls. Although 15 nM vitamin D3 had no effect, in one series of experiments 125 nM 25-hydroxyvitamin D3 elicited vascular calcium levels that were 185% of controls at 40 min. These results suggest that 1,25(OH)2D3 can act in vitamin D-replete animals to produce rapid unidirectional calcium transport responses (through unknown mechanisms), as well as by interaction with intestinal nuclear receptors in D-deficient animals to promote induction of protein(s) that support long acting calcium transport responses.

Animals↗
PubMed1984

ATP- and calcium-controlled contraction in a saponin model of Physarum polycephalum.

Saponin models of the plasmodial strand of Physarum polycephalum were constructed to study how Ca2+ and ATP regulate the generation of tension. ATP-induced isometric tension in a saponin model increased with an increase in ATP concentration until maximum tension (0.3-1.7 mg) was reached at about 1 mM. The sensitivity of the model to ATP was heightened three to five times in a basic solution containing an ATP-regenerating system, the maximum tension (0.3-0.6 mg) being reached at 0.2 to 0.3 mM ATP. Contraction of the model also depended on the Ca2+ concentration irrespective of the presence or absence of the ATP-regenerating system. The optimal pCa was 7.0, and tension decreased with a Ca2+ concentration above or below this value. These results indicate that the tension generated in the plasmodial strand of Physarum in vivo may be regulated by ATP and/or Ca2+.

Adenosine Triphosphate↗
PubMed1983

Basic and clinical evaluation of the measurement of bone resonant frequency.

A new computerized apparatus was constructed to measure the resonant frequency of human ulna in vivo with high sensitivity and reproducibility. Experimental studies using aluminum bar and dried human bone revealed the importance of the ulna being positioned parallel to the radius, approximately 90 degree flexion of the elbow joint, and minimal muscle activity in order to demonstrate maximum resonant frequency of ulna. Measurement of bone resonance in monkeys in vivo and after removal of the bone in vitro showed good agreement. Product of F (maximum resonant frequency in Hz) and L (ulnar length in cm), FL, indicating the speed of propagation of sound wave through the ulna, showed a significant positive correlation with bone mineral content/bone width (BM/BW) measured by Norland-Cameron apparatus and age-bound decline in both sexes. Patients with osteomalacia and primary hyperparathyroid bone disease tended to have higher FL values than expected from BM/BW. Two-dimensional display of FL and BM/BW thus appears to be useful in distinguishing osteoporosis from osteomalacia better than the use of BM/BW alone.

Adolescent↗
PubMed1983

Relationship of cigarette smoking and radiation exposure to cancer mortality in Hiroshima and Nagasaki.

Cancer mortality among 40,498 Hiroshima and Nagasaki residents was examined in relation to cigarette smoking habits and estimated atomic bomb radiation exposure level. Relative risk (RR) models that are either multiplicative or additive in the two exposures were emphasized. Most analyses were directed toward all nonhematologic (ANH) cancer, stomach cancer, lung cancer, or digestive tract cancer other than stomach cancer, for which there were, respectively, 1,725, 658, 281, and 338 deaths in the follow-up period for this study. Persons heavily exposed to both cigarette smoke and radiation were found to have significantly lower cancer mortality than multiplicative RR models would suggest for ANH cancer, stomach cancer, and digestive tract cancer other than stomach cancer. Surprisingly, the RR function appeared not only to be submultiplicative for some of these cancer site categories but also may be subadditive. The lung cancer RR function could not be distinguished from either a multiplicative or an additive form. The number of deaths was sufficient to permit some more detailed study of ANH cancer mortality: RR functions appeared to be consistent between males and females, though a paucity of heavy smoking females limits the precision of this comparison. The submultiplicative nature of the RR function mentioned above was particularly pronounced among persons who were relatively young (less than or equal to 30 yr of age) at the time of radiation exposure. The RR function for these younger subjects depends strongly on both radiation and cigarette smoke exposure levels. Even light smoking (approximately 5 cigarettes/day) for an extended period of time was associated with a large estimated RR. Implications of these findings are discussed in relation to human carcinogenesis models. As a byproduct, cancer mortality of several sites is significantly related to radiation exposure in this population, after accommodation for the possible confounding effects of cigarette smoking.

Adult↗
PubMed1982

A case of multiple endocrine neoplasia type II b: endocrinological evaluation and family screening.

The case of a 27 year-old woman with typical manifestations of multiple endocrine neoplasia type II b is reported. Medullary carcinoma of the thyroid was detected on the occasion of an operation for goiter when she was 22 years of age. Constipation due to megacolon caused by intestinal neuroma had persisted since childhood. Neuroma of the tongue and lips, hypertrophic corneal nerve and Marfanoid habitus were also found. The presence of pheochromocytoma was suggested in view of the positive cold pressor and results of glucagon loading tests, but this remains inconclusive. There was prolonged and exaggerated response of growth hormone and luteinizing hormone after provocative tests for anterior pituitary gland, in spite of normal basal levels. Screening of her family members for medullary carcinoma of the thyroid was carried out by measurement of immunoreactive calcitonin. Two siblings were shown to be hypercalcitoninemic, presumably due to occult medullary carcinoma of the thyroid. This case appeared to be the first in Japan showing multiple endocrine neoplasia type II b accompanied by familial hypercalcitoninemia.

Adrenal Gland Neoplasms↗
PubMed1982

Specific binding sites for epidermal growth factor and its effect on human chorionic gonadotrophin secretion by cultured tumour cell lines: comparison between trophoblastic and non-trophoblastic cells.

Using human trophoblastic (SCH) and nontrophoblastic (HeLa S3) tumour cell lines, specific binding sites for epidermal growth factor (EGF), a potent stimulator of growth in many tissues, and its effect on secretion of human chorionic gonadotrophin (hCG) and/or its subunits were compared between these two tumour cells. Both SCH and HeLa S3 cells possessed two populations of specific binding sites for 125I-labelled EGF: the high affinity (Kd approximately 10(-10) M) and the low affinity (Kd approximately 7 x 10(-10) M) system. Tetradecanoyl phorbol acetate (TPA), a tumour promotor, showed a potent competitor of labelled tracer binding to its receptor sites in both cell lines. EGF stimulated both hCG-alpha and hCG and/or hCG-beta secretion in a dose-responsive manner from SCH cells, whereas it had no effect on hCG-alpha secretion from HeLa S3 cells. In contrast, dibutyryl cyclic AMP plus theophylline, a phosphodiesterase inhibitor, enhanced hCG-alpha secretion from both cells, while TPA had no effect in either cells. These data suggest that EGF may play a physiological role in hCG secretion from trophoblastic tissues and that the mechanism by which hCG and/or its subunits are secreted may differ between trophoblastic and non-trophoblastic tumour cells.

Bucladesine↗
PubMed1982

[Fundamental and clinical studies of cefotaxime during the perinatal period in pregnant women].

Fundamental and clinical studies of cefotaxime (CTX) were carried out in pregnant women. The following results were obtained. CTX was more rapidly eliminated from the serum of pregnant women than that of adult males. Urinary excretion of CTX in pregnant women was comparable to that in nonpregnant women and adult males. Passage of CTX to the embryo, fetus and fetal appendages was minimal. Peak amniotic fluid concentration (9.8 mcg/ml) was attained at 3.5 hours after administration of CTX and gradually declined thereafter. This amniotic fluid concentration was sufficiently higher than reported MIC90 of CTX against E. coli strains. CTX was used in the treatment of 6 pregnant patients with acute pyelonephritis and 2 with puerperal infections. The bacteriological and clinical responses were both 100%. Since passage of CX into the amniotic fluid is favorable, CTX can be expected to be effective for the prophylaxis of intrauterine amniotic infection associated with early rupture of the membrane. CTX was used in the treatment of a neonate with purulent meningitis. The clinical response was effective. CTX did not cause any noteworthy adverse reactions or laboratory data abnormalities in our patients or neonates.

Adult↗
PubMed1981

Simultaneous oscillations of Ca2+ efflux and tension generation in the permealized plasmodial strand of Physarum.

Calcium is now generally thought to play a key role in regulating a variety of cellular movements. When the plasmodium of Physarum polycephalum was treated with the calcium-ionophore A23187 or the quasi-ionophore amphotericin B, Ca2+ leaked out. Ca2+ efflux into the ambient solution from the plasmodial strand segment was measured by the luminescence of a photoprotein aequorin, and the tensile force production was recorded simultaneously. Ca2+ efflux oscillated with the same period as the cycle of tension generation in the strand, but the phase of cyclic changes in Ca2+ efflux was opposite to that of tension generation. That is, Ca2+ efflux fell in the increasing tension phase and rose in the decreasing tension phase. Cyclic changes in efflux of Ca2+ are provisionally interpreted as reflecting corresponding changes in concentrations of free Ca2+ in the cytoplasm.

Calcimycin↗