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Biomedical subjects

T Ishigami

Publications and source records attributed to T Ishigami.

103 records · Page 6Linked to original sources
PubMed1983

Differences in prostaglandin E2, prostaglandin F2 alpha and prostacyclin contents and their response to thyrotrophin stimulation and in prostaglandin-stimulated cyclic AMP response in normal and Grave's thyroid slices.

The human thyroid contained prostaglandin (PG) E2, PGF2 alpha and 6-oxo-PGF1 alpha, an end-metabolite of prostacyclin (PGI2), the 6-oxo-PGF1 alpha content being the highest of these prostaglandins. Graves's thyroid contained a significantly higher amount of PGF2 alpha and lower amounts of PGE2 and 6-oxo-PGF1 alpha than the normal thyroid. Thyrotrophin acutely augmented the thyroid contents of PGE2, PGF2 alpha and 6-oxo-PGF1 alpha. The TSH-stimulated increases in PGE2 and 6-oxo-PGF1 alpha were lower but the TSH-stimulated increase in PGF2 alpha was significantly higher in Graves's thyroid than in the normal thyroid. Prostaglandin E2 and PGI2 stimulated human thyroid cyclic AMP synthesis, with the magnitudes of PGE2- and PGI2-stimulated increases in cyclic AMP being equal in normal and Graves's thyroid. Prostaglandin F2 alpha did not stimulate cyclic AMP synthesis significantly. These results provide evidence that prostaglandins play important roles in thyroid physiology and the pathophysiology of Graves's disease.

6-Ketoprostaglandin F1 alpha↗
PubMed1976

[Efficiency of microbe filtration of air filter for rearing germfree animals (author's transl)].

Filtration efficiency of 3 types of air filter frame and cylinder (Fig. 1) was examined by culture of the air obtained from the operating isolators at intervals of 3 to 21 days. The air of isolator was bubled in 30 ml of nutrient broth for 30 or 120 minutes (4approximately15 l/min.) and each of 1 ml of the broth was inoculated into thioglycollate medium (TGC), cooked meat medium (CMM), heart infustion broth (HIB) and glucose peptone water (GPW). The media were incubated for 7 to 14 days at 30 or 25 degrees C. As seen in Table 1, microbes could be effectively removed through all types of filter for over 10 months, though there were a very few positive cases suggesting technically acidental contamination at sampling.

Air Microbiology↗
PubMedDate not supplied

Postnatal ontogeny of catecholamine and somatostatin neuron systems in the median eminence of the rat as revealed by a colocalization technique.

The ontogenetic development of catecholamine (CA) and somatostatin containing nerve terminals in the rostral, central and caudal median eminence (ME) of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. Somatostatin terminals were detected earlier in development than CA terminals and had already appeared in the lateral part of the external layer of the central ME by the 1st postnatal day. CA nerve terminals were first observed in the same region of the ME on the 7th postnatal day. At about this stage both types of terminals seemed to show early signs of a correlation in their distribution which became progressively closer as maturation proceeded. Their distribution reached a stable condition in density and pattern on the 21st postnatal day when the majority were found in the lateral part of the external layer of the central ME, in the basal part of the brain just dorsal to the tuberoinfundibular sulcus and in the upper and lower labia of the tuberoinfundibular stalk. They subsequently matured to the adult pattern of stabilized distribution and anatomical relationship. It was also established that on the 28th postnatal day the somatostatin immunoreactive terminals reached a greater concentration than at any other stage of development including that of the adult.

Aging↗
PubMedDate not supplied

An important effect of TSH on prostacyclin concentration in porcine thyroid cells.

Fresh thyroid slices obtained from normal pigs contained prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha) and prostacyclin (PGI2, measured as the end metabolite, 6-keto PGF1 alpha), but the concentrations of PGI2 exceeded those of PGE2 and PGF2 alpha. A preferential increase of PGI2 was produced when the slices were exposed to a large dose of TSH (thyroid-stimulating hormone). When thyroid cells were isolated and cultured in the absence of TSH, thyroidal concentrations of PGI2, PGE2 and PGF2 alpha were about equal. When the cells were acutely exposed to a large dose of TSH, intrathyroidal concentration of prostaglandin increased significantly, but the relative concentrations of prostaglandins were not markedly altered. When thyroid cells were cultured in the presence of a small dose of TSH, relative concentrations of thyroidal prostaglandins were comparable to those of fresh thyroid slices, as a result of a preferential increase of PGI2 and decreases of PGE2 and PGF2 alpha. Further increase of PGI2 was induced when the cells cultured with TSH were acutely exposed to a large dose of TSH. It is concluded that although cells contain PGE2, PGF2 alpha and PGI2, a preferential accumulation of PGI2 is found only when thyroid cells are chronically stimulated by TSH.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Angiotensin II receptors in cardiac left ventricles of Dahl rats.

1. Dahl Iwai salt-sensitive (DS) rats have been reported as becoming hypertensive with left ventricular hypertrophy (LVH) and heart failure when on a high-salt diet. Their circulating renin-angiotensin system (RAS) has been reported to be suppressed. To evaluate the role of angiotensin II (AngII) type 1 and type 2 receptors (AT1 and AT2, respectively) in LVH, we compared cardiac AT1 and AT2 receptors in 10-week-old DS rats and Dahl Iwai salt-resistant (DR) rats. 2. Seven pairs of 6-week-old male DS and DR rats were fed either a low- or high-salt diet (0.3 or 8% NaCl, respectively) for 4 weeks. Left ventricular AngII receptors were measured by radioligand binding assays using [125I]-[Sar1,Ile8]-AngII in plasma membrane fractions from these four groups. The AT1 and AT2 receptors were distinguished using their specific antagonists CV 11974 and PD 123319, respectively. 3. The high-salt diet increased blood pressure and the left ventricle:bodyweight ratio in DS rats. However, neither Bmax for AT1 and AT2 receptors nor Kd for [125I]-[Sar1,Ile8]-AngII differed between the groups. These results are different from those of other reports of pressure-overload LVH, such as spontaneously hypertensive rats or renovascular hypertension rats, in which AT1 and AT2 receptors were reported to be up-regulated.

Animals↗