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Biomedical subjects

A Nishio

Publications and source records attributed to A Nishio.

At least 145 records · Page 8Linked to original sources
PubMed1989

Multiple types of voltage-dependent Ca channels in mammalian intestinal smooth muscle cells.

(1) Whole-cell and single channel recording techniques have been applied to smooth muscle cells isolated from guinea-pig taenia coli to examine whether multiple types of Ca channels exist. (2) Whole-cell recordings under physiological Ca concentration (1.8 mM) revealed two current components with fast and slow inactivating kinetics. The fast inactivating component was present when cells were held at very negative potentials (-80 mV). It was insensitive to the dihydropyridine (DHP) derivative, nifedipine. In contrast, the slow inactivating component was present at less negative holding potentials. It was blocked by nifedipine. (3) The two current components were found to have closely similar voltage dependencies for activation. (4) These results suggest that the fast inactivating decay of the Ca current was mediated not only by the entry of Ca into the cell but also by a voltage-dependent process via a different type of Ca channel with fast inactivating kinetics. (5) Recordings from cell-attached membrane patches with 100 mM external Ba clearly showed the existence of multiple types of Ca channels with different conductances. (6) The large conductance channels (30 pS) activated at more positive potentials (0 mV) and their averaged current decayed much more slowly. The DHP Ca antagonist, nifedipine, inhibited the large conductance channels increasing the proportion of blank sweeps and reducing the averaged current. On the other hand, the DHP Ca-agonist, BayK 8644, increased the average current by increasing the mean open-times of the large conductance channels. The presence of micromolar Cd in the patch pipettes produced a flickering block of the large conductance channels.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Surgical treatment and radiological consideration of supergiant cerebral aneurysms.

We have collected four cases of supergiant cerebral aneurysm, each greater than 6.0 cm in diameter. Two of these cases were saccular aneurysms of the anterior communicating artery and middle cerebral artery, of which the necks were clipped with resection of the aneurysms. Another patient had a fusiform aneurysm of the middle cerebral artery, which was resected accompanied by a reconstructive procedure of cerebral blood flow. The last patient had a fusiform aneurysm of the internal carotid artery. Following internal carotid artery occlusion surgery with superficial temporal artery-middle cerebral artery anastomosis, the aneurysm completely disappeared radiologically within several months.

Adolescent↗
PubMed1989

Lateral situated sinus pericranii. Case report.

We hereby report a case of a laterally situated sinus pericranii, which is rare. According to the articles regarding this kind of lesion, carotid angiograms revealed no pathological findings, and venograms taken with direct injection of contrast medium into the mass were useful. It should be stressed that the lesion could be demonstrated in the late phase of carotid angiograms, and digital subtraction angiography was especially useful for diagnosis. The literature is also reviewed.

Angiography, Digital Subtraction↗
PubMed1989

[T cell receptor delta chain gene rearrangement in acute unclassified leukemia].

A 31 year-old male who was treated with radiation under the diagnosis of malignant lymphoma was admitted to our hospital because of systemic erythema and tumor of bilateral upper arms in October, 1987. Leucocyte count of peripheral blood showed 4,400/microliters with 36% leukemic cells and bone marrow was hypercellular with 85.6% leukemic cells. Leukemic cells were negative for peroxidase reaction and lineage specific monoclonal antibodies such as CD3, CD4, CD8, CD10, CD19 and CD20. T cell receptor (TCR) delta gene was rearranged but TCR beta, TCR gamma and immunoglobulin (Ig) genes were in germline configuration. He was treated with combination regimen of doxorubicin, vindesine, prednisolone and L-asparaginase, and complete remission was obtained. These observations suggest that TCR delta gene rearrangement is useful for determination of clonality in cases without rearrangements of the other TCR and Ig genes.

Acute Disease↗
PubMed1989

Enhanced contractile response to noradrenaline and calcium influx in thoracic aorta isolated from dietary magnesium deficient rats.

Dependency on extracellular calcium influx in contractile response to noradrenaline has been investigated in the thoracic aorta isolated from dietary magnesium (Mg) deficient rats. Adult male Wistar rats were fed with a Mg deficient diet (0.001% Mg) for 30 days, together with control groups (0.07% Mg). The contractile response to noradrenaline in the thoracic aortas from Mg deficient rats was significantly greater than that in the controls. However, there were no significant differences between control and Mg deficient rats in the contractile response to high potassium. The rate of 45Ca uptake induced by noradrenaline was greater in Mg deficient rat aortas than in the controls, but that induced by high potassium showed no significant differences between control and Mg deficient rats. Calcium entry blockers (verapamil and nifedipine) caused a concentration-dependent depression of the noradrenaline-induced contraction. The aortas from Mg deficient rats were more sensitive to these drugs than were those from the controls. These results suggest that the noradrenaline-induced contraction depends much more on extracellular calcium influx in Mg deficient rats than in the controls.

Animals↗
PubMed1989

[Triploid clone observed at blastic crisis in chronic myelogenous leukemia with complex Ph1 translocation (9; 22; 12)].

A 56-year-old female, who was diagnosed as CML in 1983 and had been well controlled with busulfan, was admitted to our hospital because of fever and iliac bone pain. Peripheral blood showed leukocytosis (WBC 70,000/microliters and bone marrow was normocellular with 53% leukemic cells, suggesting that she was in the blastic crisis. Chromosomal analysis of bone marrow cells at that time revealed t (9; 22; 12) and some additional abnormalities. The number of chromosomes ranged from 44 to 131 and the mode of chromosome number was 65. She was treated with combination regimen consisting of vincristine, 6-mercaptopurine and prednisolone and right iliac tumor was irradiated. Three months after admission, she died of DIC and pulmonary insufficiency due to leukemic infiltration.

Blast Crisis↗
PubMed1988

Whole-cell and unitary Ca channel currents in mammalian intestinal smooth muscle cells: evidence for the existence of two types of Ca channels.

Whole-cell and single Ca channel currents were recorded in smooth muscle cells isolated from guinea-pig taenia coli to examine whether multiple types of Ca channels exist. Two different types of voltage-dependent Ca channels with different conductances and inactivation kinetics were identified from cell-attached patch clamp recordings using 50 mM Ba in the patch pipettes. One type of channel, with a large conductance of 25 pS, had a threshold of activation near -40 mV and the mean current reconstructed by averaging individual current responses inactivated slowly. A second type of channel, with a small conductance of 12 pS, had a similar threshold value to that of the 25 pS channel, but the averaged current inactivated rapidly. The steady state inactivation of the 12 pS channel was complete at a holding potential of -40 mV. We concluded that both channel types represent fast and slow inactivating voltage-dependent Ca channels which have been found in many excitable cells.

Animals↗
PubMed1988

Translocations t(15;17) and t(9;14)(q34;q22) in a case of acute promyelocytic leukemia with increased number of basophils.

A patient with a variant form of acute promyelocytic leukemia (M3 variant) associated with an increased number of basophils was found to present a reciprocal translocation, t(9;14)(q34;q22) in addition to t(15;17)(q22;q12). Although several cases of acute nonlymphocytic leukemia with increased bone marrow and peripheral blood basophils have been reported, this is the first case in which both the t(9;14) and basophilia were observed in a patient with M3. Our findings support the hypothesis that 9q34 may be associated with the chromosomal location of genes regulating the production and maturation of basophils.

Adult↗
PubMed1988

Calcium channel modulation by the dihydropyridine derivative Bay K 8644 in mammalian visceral smooth muscle cells.

1. Modulation of Ca channels by the dihydropyridine Ca agonist Bay K 8644 in guinea-pig taenia coli smooth muscle cells was investigated using the patch clamp technique. 2. Single Ca channel activity was obtained from cell-attached patch recordings with the use of pipettes filled with 50 mM Ba. Bath application of the drug markedly increased the opening probability of Ca channels. 3. The effect was found to be due to an increase in the mean opening times of Ca channels. Due to this increase, the mean current reconstructed by averaging individual current trace responses was markedly increased in the presence of Bay K 8644.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1988

Histamine metabolism and pinnal hyperaemia during magnesium deficiency in rats.

The relation between histamine metabolism and an appearance of pinnal hyperaemia during magnesium (Mg) deficiency, and the effects of some factors on these were studied in 3-week-old Wistar rats. On a Mg-deficient diet (Mg 0.001%), the histamine concentrations in plasma and urine increased after 4-5 d, and reached a maximum after 6-12 d. Pinnal hyperaemia appeared during the same time course. The hyperaemia was reduced by the administration of antihistamines (cimetidine and diphenhydramine). These results indicate that pinnal hyperaemia during Mg deficiency is mediated by histamine. The administration of oestradiol benzoate (0.08 mg/100g body weight subcutaneously once a day for 8 d) and/or gamma-ray irradiation (600 rad/d before experiments) reduced the appearance of pinnal hyperaemia and the increment in the urinary histamine during Mg deficiency. The histamine content increased in the spleen and some tissues after 8 d, but not in the skin, with increasing the activity of histamine synthesis. The treatments mentioned above depressed the increment of histamine content. These results suggest that the pinnal hyperaemia and the increment of the urinary histamine in the Mg-deficient rat are related to the increment of both the histamine synthesis and release.

Amine Oxidase (Copper-Containing)↗
PubMed1988

Ex vivo study of the vascular reactivity to some vaso-active agents in isolated thoracic aorta from dietary magnesium-deficient rats.

We have reported that dietary magnesium (Mg) deficiency induced both histaminaemia and hypomagnesaemia in rats. In this study, the effects of dietary Mg deficiency on the reactivity of the isolated thoracic aorta to some vaso-active amines were studied ex vivo. Adult male Wistar rats were fed on a Mg-deficient diet (Mg 0.001%) and a control diet (Mg 0.07%) for 30 d. Sensitivity to KCl and adrenaline showed no significant change during Mg deficiency. In Mg-deficient rats, the sensitivity to noradrenaline was higher than in the control group. Removal of calcium ions from the medium in the tissue bath resulted in a greater decay of noradrenaline-induced contraction in Mg-deficient rats than in the control rats. Endothelium-dependent relaxation was also examined in isolated aortic strips precontracted with noradrenaline. In rats which were fed with the Mg-deficient diet for 15 days, histamine produced less relaxation than in the control group, but acetylcholine produced the same degree of relaxation as in the controls. These results showed that hypomagnesaemia and histaminaemia might influence the reactivity of the aorta in vivo.

Acetylcholine↗
PubMed1988

Comparative effects of magnesium salts on reactivity of arterioles and venules to constrictor agents: an in situ study on microcirculation.

The influence of different magnesium salts (i.e., MgCl2, MgSO4, Mg aspartate HCl and Mg acetate) on reactivity of rat mesenteric arterioles (10-25 micron I.D.) and venules (15-30 micron I.D.) to standard constrictor doses of epinephrine and BaCl2 was examined utilizing perivascular, i.a. and i.v. administration of each Mg salt. Perivascular application (0.1, 1.0 and 10 mumol) of the four Mg salts on the microvessels attenuated the vasoconstrictor actions of both epinephrine and BaCl2, dose-dependently. With respect to arterioles, the vasoconstriction induced by BaCl2 was inhibited more potently by each Mg salt than that induced by epinephrine; the reverse was observed with respect to the venules. MgCl2 displayed the most potent antagonism to the constriction induced by BaCl2 in arterioles as well as by epinephrine in venules. Infusion of each Mg salt in very low doses (e.g., 0.1 mumol/min i.a.) resulted in significant attenuation of the arteriolar constrictions induced by both stimulants. However, the difference in the degree of attenuation on i.a. infusion of each Mg salt was significantly less than that observed by perivascular pretreatment. Arteriolar constrictions induced by epinephrine and BaCl2 were also attenuated by systemic i.v. infusion of each Mg salt, except for MgSO4, when low doses (e.g., 0.1 and 1.0 mumol/min.) were given; surprisingly, high dose i.v. infusion (10 and 20 mumol/min) often potentiated arteriolar constrictions induced by both stimulants, but the magnitude of this potentiation depended on the Mg salt utilized.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1987

Mg2+-Ca2+ interaction in contractility of vascular smooth muscle: Mg2+ versus organic calcium channel blockers on myogenic tone and agonist-induced responsiveness of blood vessels.

Contractility of all types of invertebrate and vertebrate muscle is dependent upon the actions and interactions of two divalent cations, viz, calcium (Ca2+) and magnesium (Mg2+) ions. The data presented and reviewed herein contrast the actions of several organic Ca2+ channel blockers with the natural, physiologic (inorganic) Ca2+ antagonist, Mg2+, on microvascular and macrovascular smooth muscles. Both direct in vivo studies on microscopic arteriolar and venular smooth muscles and in vitro studies on different types of blood vessels are presented. It is clear from the studies done so far that of all Ca2+ antagonists examined, only Mg2+ has the capability to inhibit myogenic, basal, and hormonal-induced vascular tone in all types of vascular smooth muscle. Data obtained with verapamil, nimopidine, nitrendipine, and nisoldipine on the microvasculature are suggestive of the probability that a heterogeneity of Ca2+ channels, and of Ca2+ binding sites, exists in different microvascular smooth muscles; although some appear to be voltage operated and others, receptor operated, they are probably heterogeneous in composition from one vascular region to another. Mg2+ appears to act on voltage-, receptor-, and leak-operated membrane channels in vascular smooth muscle. The organic Ca2+ channel blockers do not have this uniform capability; they demonstrate a selectivity when compared with Mg2+. Mg2+ appears to be a special kind of Ca2+ channel antagonist in vascular smooth muscle. At vascular membranes it can (i) block Ca2+ entry and exit, (ii) lower peripheral and cerebral vascular resistance, (iii) relieve cerebral, coronary, and peripheral vasospasm, and (iv) lower arterial blood pressure. At micromolar concentrations (i.e., 10-100 microM). Mg2+ can cause significant vasodilatation of intact arterioles and venules in all regional vasculatures so far examined. Although Mg2+ is three to five orders of magnitude less potent than the organic Ca2+ channel blockers, it possesses unique and potentially useful Ca2+ antagonistic properties.

Animals↗
PubMed1987

[Effects of magnesium deficiency on dermal mast cells in rats].

The effects of dietary magnesium (Mg) deficiency on dermal mast cells were studied in young Wistar rats weighing about 50 g. The rats fed with a Mg-deficient diet (0.001% Mg) showed hyperemia on the 3rd or the 4th day after they were fed the diet. The dermal mast cells of the control rats were filled with granules, while the cells of rats fed the Mg-deficient diet for 4 days contained less granules than the controls, but contained extensively dilated rough surfaced endoplasmic reticulum, well-developed Golgi complexes, many mitochondria and ribosomes. These data suggest that hypomagnesemia could induce a release of histamine from dermal mast cells. So, the effect of a low Mg medium on the release of histamine was studied using peritoneal mast cells in vitro. A low Mg medium (0.2 mM Mg) induced much more histamine release than control medium (1 mM Mg) from the peritoneal mast cells obtained from both control and Mg-deficient rats fed with the Mg-deficient diet for 2 days. The peritoneal mast cells obtained on the 8th day of Mg-deficiency released much more histamine than controls in 1 mM Mg medium. These results suggest that hyperemia observed in Mg-deficient rats depends partly on histamine released from dermal mast cells.

Animals↗
PubMed1987

[Studies on histamine containing cells in the spleen of the magnesium-deficient rats].

When young Wistar rats (body wt. 50 g) were maintained on a magnesium-deficient diet (0.001% Mg) for eight days, the splenic weight and histamine content increased about 2-fold and 30-fold, respectively, compared with those of the control rats. There was no significant difference in the number of splenic mast cells between the magnesium-deficient and control rats. More neutrophilic, eosinophilic and basophilic granular cells were found in the spleen cells isolated from the magnesium-deficient rats than in those from the control rats. Of the isolated cells from magnesium-deficient rats, 7.6% were basophilic granular cells; however, no basophilic granular cells were observed in the spleen cells isolated from the control rats. In the cytochemical study, the yellowish fluorochrome formed by the interaction of o-phthalaldehyde and histamine was found in basophilic granular cells. These results suggest that the increase in the histamine content of the spleen of magnesium-deficient rats is related to the increased number of basophilic granular cells.

Animals↗
PubMed1987

Specific change of histamine metabolism in acute magnesium-deficient young rats.

The effects of dietary magnesium (Mg) deficiency on histamine metabolism were studied. Young Wistar rats were fed a Mg-deficient diet (0.001% Mg diet) ad libitum for 8 days with control groups (0.07% Mg diet), food-restricted groups (0.21% Mg diet, but restricted to 5 g/rat/day), and refeeding groups (0.001% Mg diet for 6 days ad libitum, after that fed with a 0.21% Mg diet ad libitum for 2 days). Compared to the other groups, the plasma Mg level was markedly lower in the Mg-deficient group. A return from the lower Mg level to the controls took place after feeding them a 0.21% Mg diet for 2 days. Urinary histamine level increased rapidly after 4 days and reached a maximum on the eighth day of Mg deficiency. The high urinary histamine level in Mg-deficient rats decreased rapidly after feeding them a 0.21% Mg diet for 2 days. Histamine contents in some tissues increased on the eighth day of Mg deficiency. Other groups showed no significant change. The increased histamine content in Mg-deficient rats showed a tendency to return to control levels after feeding them a 0.21% Mg diet for 2 days. Histidine decarboxylase (HDC) activity in some tissues of Mg-deficient rats increased markedly. The increased HDC activity dropped nearly to control levels after feeding them a 0.21% Mg diet for 2 days. Diamine oxidase (DAO) activity in the duodenum was high in control rats. Duodenal DAO activity decreased gradually and reached half the value of controls on the eighth day of Mg deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Amine Oxidase (Copper-Containing)↗