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Biomedical subjects

H Fukuda

Publications and source records attributed to H Fukuda.

At least 1,207 records · Page 67Linked to original sources
PubMed1978

Comparison of pituitary-thyroid maturation in the fetuses of rats fed an iodine-deficient or normal diet.

From the earliest detectable development of fetal pituitary-thyroid function (day 18-19 of gestation) through the first postnatal day, there was a higher degree of stimulation of the pituitary-thyroid axis in the fetuses of rats fed a low iodine diet (LID) than in those of rats fed a high iodine diet (HID). Significant differences between the two groups were consistently observed in relative thyroid size, plasma TSH, 4-h thyroid radioiodine uptake, and the labeled iodoamino acid composition of thyroid digests. Plasma T4 concentration was lower in both LID and HID fetuses and pups than in the HID mothers. Plasma T3 was not detectable (less than 20 ng/dl) in the fetuses of either group, nor was labeled T3 in the thyroid digests. Body weight, plasma T4, and pituitary TSH content were usually lower in the LID than the HID animals of comparable age; however, these differences were not consistently statistically significant (P less than 0.05). We conclude that iodine deficiency causes a marked stimulation of TSH secretion and, consequently, of thyroid growth and metabolism from the earliest development of fetal pituitary-thyroid function.

Animals↗
PubMed1978

Alterations in spontaneous activity of the isolated frog spinal cord in Calcium-free environment.

Spontaneous electrical activity of the isolated frog spinal cord was examined in Ca2+-free environment. Spontaneous discharges from the ventral root altered in four distinguishable steps. The first step was an immediate increase in the rate of spontaneous discharges and the second was a gradual decrease. The third was the occurrence of rhythmical bursts, and the last, the appearance of continuous firing. The rhythmical bursts could be depressed by the addition of metabolic inhibitors (ouabain or dinitrophenol in a concentration of 5 x 10(-5) M) as well as of Ca2+-chelating agents (EDTA or EGTA in a concentration of 10(-3) M). Our results suggest that the occurrence of the rhythmical bursts requires a metabolic pumping process to redistribute Na+ and K+ across the membrane and a small amount of Ca2+ for transmitter secretion.

Animals↗
PubMed1978

Effect of active and passive immunization with TRH on plasma TSH response to propylthiouracil.

The role of thyrotropin-releasing hormone (TRH) in the secretion of TSH from the anterior pituitary was investigated in rats by active and passive immunization with TRH. The plasma TSH response to propylthiouracil (PTU) in TRH-bovine serum albumin (BSA)-immunized rats was significantly lower than that of BSA-immunized or non-immunized rats. Similarly, the increased plasma TSH level following PTU treatment was significantly suppressed after iv injection of antiserum to TRH. However, the decline in plasma TSH levels was not complete. The results of the present study indicate, at least in part, the physiological significance of endogenous TRH in the regulation of pituitary TSH secretion.

Animals↗
PubMed1978

Semiquantitative 67Ga scanning of lung cancer by scintiscoring: its usefulness in diagnosis of localization, therapeutic effectiveness, radiation pneumo-mediastinitis and recurrence.

Attempts were made to attain a semiquantitative evaluation of therapeutic effectiveness of lung cancer by scintiscoring of the liver as well as the tumor lesion. A relative counting ratio of tumor to liver was computed, and this was found useful: in areas of active tumorous growth, higher ratios were obtained. The ratios returned to the control levels following irradiation with or without an anti-inflammatory regimen including prednine. The technic is simple, and yet invaluable especially when the tumor locates in the mediastinum escaping from radiological detection. Satisfactorily frequent repetition would be competent enough in early diagnosis of developing radiation pneumo-mediastinitis and regrowths in the mediastinum and fibrotic abnormal shadows as well. The principle would be best rewarded by use of a whole-body scanner equipped with a digital computer.

Evaluation Studies as Topic↗
PubMed1977

Action of 5-(2-thienyl)valeric acid as a biotin antagonist.

5-(2-Thienyl)valeric acid (TVA), a biotin analogue which can be easily prepared through chemical process, inhibited the growth of a biotin synthesizing Rhodotorula glutinis. The growth inhibition was reversed by the addition of biotin. Among biotin intermediates, dethiobiotin and 7,8-diaminopelargonic acid reversed the inhibition by TVA, while 7-keto-8-amino-pelargonic acid and pimelic acid did not. From these results, it was concluded that TVA is a biotin antagonist which probably acts as an inhibitor of biotin biosynthesis.

Biotin↗
PubMed1977

Effects of beta-(p-chlorophenyl)-GABA (baclofen) on spinal synaptic activity.

In the isolated perfused spinal cord of the bullfrog, baclofen caused a reduction in the rate of spontaneous discharges in the ventral root at lower concentrations than GABA. The inhibitory effect of baclofen was fully present in a chloride-free medium, whereas that of GABA was markedly reduced. In contrast to GABA, which depolarized the dorsal root, baclofen produced a hyperpolarization in the dorsal root. Moreover, baclofen produced a hyperpolarization in the ventral roots. In the rat, the development of spinal reflex inhibition by baclofen was slow and the effect was long-lasting. Baclofen decreased dorsal root reflexes, suggesting a decreased excitability of presynaptic fibres. Baclofen produced a more pronounced and faster inhibitory effect on monosynaptic reflexes than on polysynaptic reflexes. In the monoamine depleted rat, the effect of baclofen on both types of reflexes was markedly reduced. It appears that catecholamines are involved in the effects produced by baclofen.

Action Potentials↗
PubMed1977

Permissive role of thyrotropin on thyroid radioiodine uptake during the recovery phase of subacute thyroiditis.

Serial measurements of serum triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH), and 4-hr thyroidal 131I uptake were carried out in nine patients with subacute thyroiditis. In the acute phase, suppressed TSH and 131I uptake were observed simultaneously with the elevations of T3 and T4. Thyrotropin-releasing hormone (TRH) failed to increase TSH in all patients studied. The mean value of an increment in serum TSH was only 1.8 muU/ml during the recovery phase when 131I uptake was normal or hypernormal. In addition, an elevated 131I uptake was not necessarily associated with an immediate increase in the serum T3 and T4. These observations suggest that the resumption of the iodide pump may be more important than an increment in TSH in producing normal or hypernormal 131I uptake during the recovery phase. There appears to be a dissociation between the reestablishment of 131I uptake and the resumption of the mechanism of hormonal synthesis and secretion in the thyroid.

Adult↗