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Biomedical subjects

N Minami

Publications and source records attributed to N Minami.

At least 127 records · Page 7Linked to original sources
PubMed1992

Plasma cytokine levels in thrombotic thrombocytopenic purpura.

Plasma cytokine levels were examined in 13 patients with thrombotic thrombocytopenic purpura (TTP). Auto-antibodies, platelet-associated immunoglobulin G, and platelet aggregating factor were detected in many of these patients and high-molecular-weight bands of von Willebrand factor multimers were reduced in 9 of 10 patients examined. Complete remission (CR) was attained in 7 of the 13 patients, but 6 died. Tumor necrosis factor (TNF), Interleukin (IL)-1 beta, IL-6, and soluble IL-2 receptor showed marked increases at onset and decreased at CR. The prognosis tended to be poor in patients with increased IL-6 and soluble IL-2 receptor levels. These findings suggest that immunological mechanisms, such as the activation of macrophage, are involved in the pathogenesis of TTP and are reflected in the plasma cytokine levels.

Adolescent↗
PubMed1992

A role for protein kinase C in the growth of human erythroid progenitor cells.

We searched for a possible role for protein kinase C in the growth of human erythroid progenitor cells, using pharmacologic approaches. Two protein kinase C inhibitors, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) and staurosporine, dose-dependently inhibited the growth of immature erythroid progenitor cells (BFU-E) induced by interleukin 3 (IL-3) plus erythropoietin (Ep) or granulocyte macrophage colony-stimulating factor (GM-CSF) plus Ep whereas a weaker analog of H-7, N-(2-guanidinoethyl)-5-isoquinoline sulfonamide (HA-1004), had no effect on the number of BFU-E. These three compounds had no effect on the growth of mature erythroid progenitor cells (CFU-E) stimulated by Ep. The culture of accessory cell-depleted bone marrow demonstrated that the effects of these compounds on colony formation do not appear to be mediated by accessory cells. The potential of these compounds to inhibit the GM-CSF-dependent growth of KG-1 cells correlated well with the extent of their inhibitor of protein kinase C activities from KG-1 cells. Thus, the protein kinase C system is apparently involved in the growth of BFU-E, supported by IL-3 or GM-CSF. The growth signal for CFU-E transduced by Ep may be achieved through other systems.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Involvement of Ca2+ entry and inositol trisphosphate-induced internal Ca2+ mobilization in muscarinic receptor-mediated catecholamine release in dog adrenal chromaffin cells.

Catecholamine (CA) release from adrenal medulla evoked by muscarinic receptor stimulation has been studied using isolated perfused adrenal gland and cultured chromaffin cells from dogs. Muscarine and oxotremorine (1-100 microM), and bethanechol (0.1-1 mM) dose-dependently stimulated CA release. Muscarine-evoked CA release was antagonized with M1-antagonist, pirenzepine and, to a lesser extent, with atropine; and was reduced either by removal of extracellular Ca2+ or treatment with Ca2+ channel blockers. Muscarine caused an increase of 45Ca uptake and 22Na uptake. Tetrodotoxin (TTX) did not affect muscarine-evoked increase of 22Na uptake and CA release. Under the absence of extracellular Ca2+, muscarine stimulated a 45Ca efflux. Muscarine-induced CA release was attenuated by treating the cells with 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate-HCl (TMB-8) which blocks Ca2+ release from the intracellular store. A phospholipase C inhibitor, neomycin, markedly reduced muscarine-induced CA release but not nicotine- and high K(+)-evoked release. Cinnarizine, a Ca2+ channel blocker, attenuated muscarine-evoked but not caffeine-induced CA release and 45Ca efflux in the absence of extracellular Ca2+. Muscarine caused an increase in intracellular free Ca2+ concentration ([Ca2+]i) in the presence of extracellular Ca2+. It caused a similar increase, but to a lesser extent, in the absence of extracellular Ca2+. The increase of [Ca2+]i induced by muscarine without extracellular Ca2+ was reduced by neomycin and cinnarizine. Polymixin B and retinal, which reduced 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced CA release, had little effect on muscarine-induced CA release. Muscarine increased cellular Ins(1,4,5)P3 production, and atropine inhibited this increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1992

The accuracy and performance of the A&D TM 2421, a new ambulatory blood pressure monitoring device based on the cuff-oscillometric method and the Korotkoff sound technique.

The accuracy and performance of the A&D TM 2421, a new ambulatory blood pressure (BP) monitoring device using both the cuff-oscillometric method (O) and the Korotkoff sound method (K) were evaluated. The device was tested for accuracy under static and dynamic conditions by simultaneous comparison with two observers using a standard mercury column sphygmomanometer (standard method) and by the objective recording method (ORM). The performance of the device was also evaluated under ordinary ambulatory conditions. The mean differences in BP of standard method from K-method were -1.2 +/- 4.7 mm Hg systole and 1.3 +/- 4.7 mm Hg diastole (n = 323, mean +/- SD) and those of standard method from O-method were -0.4 +/- 5.3 mm Hg systole and 1.4 +/- 5.1 mm Hg diastole (n = 323). The agreement between each of the two methods of the device and the standard method was within 10 mm Hg for more than 90% of both systolic and diastolic readings. During bicycle exercise, the mean differences in BP of standard method from K-method were -3.4 +/- 4.8 mm Hg systole and 1.8 +/- 5.2 mm Hg diastole (n = 71) and those of standard method from O-method were -1.1 +/- 7.3 mm Hg systole and 1.7 +/- 7.8 mm Hg diastole (n = 67). There was a greater scatter in the individual comparisons of the device and the standard method during exercise, especially in diastolic BP. The relation between the device and ORM was almost similar to that between the device and the standard method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Synthesis and antiarrhythmic activity of 2,2-dialkyl-1'-(N-substituted aminoalkyl)-spiro-(chroman-4,4'-imidazolidine)-2',5'-diones.

A novel series of 2,2-dialkyl-1'-(N-substituted aminoalkyl)-spiro-[chroman-4,4' -imidazolidine]-2',5'-diones was synthesized and evaluated for antiarrhythmic activity in chloroform- or/and aconitine-induced ventricular arrhythmia in mice. Among these compounds, (-)-6-chloro-2,2-dimethyl-1'-[3-(4-hydroxypiperidino)propyl] -spiro-[chroman-4,4'-imidazolidine]-2',5' -dione was found to be more effective than reference agents and was selected for further development.

Animals↗
PubMed1992

Synthesis and cardiovascular activity of phenylalkylamine derivatives. I. Potential specific bradycardic agents.

A series of acyclic amide derivatives of N-(omega-aminoalkyl)-N-methylhomoveratrylamine was synthesized and evaluated for their bradycardic activity in isolated guinea pig right atria. Among these compounds, (E)-N-[3-[N'-[2-(3,4-dimethoxyphenyl)ethyl]-N'-methylamino]propyl]- 4-[3,4-(methylenedioxy)phenyl]-3-butenamide (35) was the most potent in vitro and was also found to show dose-dependent bradycardia without remarkable reduction of left ventricular dp/dtmax or mean aortic pressure in anesthetized dogs.

Animals↗
PubMed1992

Effects of low molecular weight oviductal factors on the development of mouse one-cell embryos in vitro.

The relationship between the oviduct and embryo development in the mouse was investigated and the period at which the influence of oviduct can be concerned in the development of mouse embryos in vitro was identified. In addition, the relative molecular weight of oviductal factors that promote embryo development was demonstrated. Mouse zygotes developed to the blastocyst stage when co-cultured with ampulla. The period of embryo co-culture significantly affected the further development of the embryos. Fewer one-cell embryos co-cultured with dissected ampullae for less than 24 h developed to blastocysts than those co-cultured for more than 28 h (P < 0.001). A high percentage of embryos co-cultured with ampullae after 24 h of culture in vitro developed to the blastocyst stage, which suggests that the influences of ampulla on the development of mouse embryos are restricted to a specific period at the two-cell stage (about 55-56 h after hCG injection) in vitro. Mouse ova that were cultured in media conditioned by ampullae could also develop to the blastocyst stage. The fractionated medium that contained low molecular weight fractions was more effective (P < 0.001) on the development of embryos to the blastocyst stage than that containing high molecular weight fractions. These results suggest that the low molecular weight oviductal factors play an important role in the development of mouse embryos at a certain critical age in vitro.

Animals↗
PubMed1992

Circadian blood pressure variation in patients with renovascular hypertension or primary aldosteronism.

Circadian blood pressure (BP) variation were studied in patients with renovascular hypertension (RVH) and primary aldosteronism (PA). Ambulatory BP (ABP) was monitored every 5 min for 24 hrs in a ward setting in 23 patients with PA and 17 patients with RVH (13 patients with unilateral renal arterial stenosis and 4 with bilateral stenosis). In patients with RVH, ABP was monitored before and after treatment with a converting enzyme inhibitor or percutaneous transluminal angioplasty. Plasma renin activity (PRA) was high before percutaneous transluminal angioplasty in almost all patients with RVH and low in those with PA. Ordinary circadian BP variation, i.e. nocturnal fall and diurnal rise in BP, was confirmed in the patients with unilateral or bilateral renal artery stenosis. Percutaneous transluminal angioplasty successfully normalized both BP and PRA in those with RVH. Normal circadian BP variation was observed in those with RVH before the treatment with a converting enzyme inhibitor or percutaneous transluminal angioplasty as well as during treatment with the former and after treatment with the latter. Circadian BP variation in the patients with RVH was affected by the pathogenesis of renal artery stenosis alone, i.e, fibromuscular hyperplasia and atherosclerosis; with fibromuscular hyperplasia normal circadian BP variation was observed, while with atherosclerosis, nocturnal BP fall was restricted or eliminated. Circadian BP variation in those with PA before and after excision of adrenal adenoma was essentially similar to that in normal subjects and essential hypertensive patients. From these it seems that in patients with RVH or PA, circadian BP variation is not affected by hypertension per se or by pathogenesis of hypertension.

Adenoma↗
PubMed1992

Endothelin-1 of canine basilar artery in vasospasm.

Cerebral vasospasm was induced in adult mongrel dogs by a two-hemorrhage method. The basilar arteries were quickly frozen after careful removal of surrounding blood clot and their level of immunoreactive endothelin-1, a strong vasoconstrictor produced by the endothelial and vascular smooth-muscle cells, was measured by sandwich-enzyme immunoassay. The levels of immunoreactive endothelin-1 (mean +/- standard deviation) were 112.9 +/- 7.0 pg/mg protein prior to vasospasm, 180.4 +/- 24.7 pg/mg protein on Day 2 after vasospasm, and 115.0 +/- 24.0 pg/mg protein on Day 7, showing a significant increase (p less than 0.01) in immunoreactive endothelin-1 only on Day 2. In addition, vasospasm was moderately reversed by the topical application of monoclonal antibody against endothelin-1 on Day 2 but rather resistant to topical monoclonal antibody on Day 7. It is suggested that endothelin-1 could act as a trigger in the early stages of cerebral vasospasm, but that the maintenance of cerebral vasospasm at later stages might be independent of endothelin-1.

Animals↗
PubMed1992

Effects of inhibitors of protein kinase C and calpain in experimental delayed cerebral vasospasm.

Vasospasm was produced in adult mongrel dogs by a two-hemorrhage method, and the spastic basilar arteries were exposed via the transclival route on Day 7. Tonic contraction was produced in the normal canine basilar arteries by a local application of KCl or serotonin after transclival exposure. The exposed spastic and tonic basilar arteries then received a topical application of the following: 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H-7), a potent inhibitor of protein kinase C acting at the catalytic domain; calphostin C, a specific inhibitor of protein kinase C acting at the regulatory domain; or calpeptin, a selective inhibitor of calpain. Both spastic and tonic basilar arteries were effectively dilated by H-7. Calphostin C caused only slight dilation of spastic basilar arteries but moderate dilation of tonic basilar arteries. Dilation in response to calpeptin was remarkable in the spastic basilar arteries but slight in the tonic basilar arteries. The doses of calphostin C and calpeptin required to obtain maximum effect were markedly lower in the tonic model than in the spastic model. The spastic and tonic models had a similar dose-dependent response to H-7 but quite a different response to calphostin C or calpeptin, suggesting a difference in the function of protein kinase C and calpain in the two models. Furthermore, the effect of calphostin C on the reversal of vasospasm was increased significantly after topical treatment with calpeptin. It is suggested that the majority of the catalytic domain of protein kinase C is dissociated from the regulatory domain, probably by a limited proteolysis with calpain, and is markedly activated in vasospasm.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Effect of slow release nifedipine tablets in patients with essential hypertension.

The antihypertensive effect of slow release nifedipine (CAS 21829-25-4) tablets (20 mg, Adalat) administered once or twice daily was studied in patients with essential hypertension of WHO stage I or II. Ambulatory blood pressure was monitored by a finger volume oscillometric device every 5 min for 24 h before and during the treatment with nifedipine. Whether administered once or twice daily, nifedipine tablets dit not change the pattern of circadian blood pressure variation; i.e. diurnal rise and nocturnal fall. Twice daily administration induced a significant downward shift in the blood pressure pattern. In other words, further hypotensive effect was observed during the night when the blood pressure was already low. On the other hand, administration once daily in the morning lowered daytime blood pressure without affecting blood pressure during the night. The duration of action of nifedipine tablets administered once daily was 12 h or more. In the acute experiment using 20 mg tablets of nifedipine, plasma concentration of nifedipine was well correlated with the percentage change in mean blood pressure. The minimal effective plasma concentration of nifedipine was estimated to be 13.4 ng/ml. However, in chronic treatment, nifedipine lowered blood pressure at the plasma concentration of 10 ng/ml. The results indicate that nifedipine tablets administered once daily provide an effective antihypertensive regimen for controlling daytime hypertension with minimal antihypertensive effect during the night.

Adult↗
PubMed1992

[Idiopathic thrombocytopenic purpura associated with pregnancy].

We examined 14 patients (18 cases) with idiopathic thrombocytopenic purpura (ITP) during pregnancy at our department. ITP, which had improved, recurred during pregnancy in 4 cases while it developed for the first time during pregnancy in 10 cases. In the other 4 cases, pregnancy occurred in the course of ITP. Although a normal infant was born in 14 cases, 3 stillbirth and a premature infant was observed in 4 cases. Six deliveries had some toxemia of pregnancy. A transient decrease in neonatal platelets was observed in 4 of 14 cases and mother's platelets count was less than 40 X 10(3)/microliters in the 4 cases. Although antinuclear antibody, Coomb's test and antiphospholipid antibody were positive in some cases, these were not markedly related to clinical course or neonatal platelets count. Eleven cases were treated with glucocorticoids, high dose gamma globulin or platelets transfusion, but 11 cases were not treated. Since ITP is frequently observed during pregnancy and may be some risk factor for pregnancy, treatment of ITP is important during pregnancy.

Adult↗
PubMed1992

[Plasma interleukin-6 in patients with disseminated intravascular coagulation].

Plasma Interleukin-6 (IL-6) level was measured in 60 patients with disseminated intravascular coagulation (DIC). Plasma IL-6 level was high in patients with DIC, and was particularly high in patients with multiple organ failure (MOF) or poor prognosis. Plasma IL-6 level correlated positively with C-reactive protein in patients without DIC, but not in those with DIC. The increased plasma IL-6 level observed in DIC patients suggests that activation of the immune system is involved in the progression of DIC and in the pathology of organ failure.

Adult↗
PubMed1991

Immunohistochemistry of leukotriene C4 in experimental cerebral vasospasm.

Experimental cerebral vasospasm was produced in a "two-hemorrhage" canine model and examined by immunohistochemistry for leukotriene C4 (LTC4). The immunostain for LTC4 showed a strong positivity in intima and adventitia and a scattered reaction in media of normal basilar artery. The immunoreactivity after subarachnoid hemorrhage (SAH) was little changed in intima and media. Inflammatory cells which were characterized histochemically as neutrophils and macrophages, were shown to infiltrate from the adventitia of basilar artery to the periphery of blood clot after SAH and were markedly immunoreactive for LTC4. Also the neutrophils increased in number with the lapse of time after SAH. Thus, it would be reasonable to conclude that the LTC4 responsible for the development of vasospasm would most likely be produced from the infiltrating neutrophils and macrophages. In addition, neurons in hypothalamus, median eminence, and pons, as well as ependymal and arachnoid cells were immunoreactive for LTC4 both in the control and after SAH, whereas astrocytes and oligodendrocytes were not immunoreactive for LTC4 in either case.

Animals↗
PubMed1991

Purification and tissue distribution of rat epidermal growth factor.

1. Two forms of rat epidermal growth factor, EGF-I and EGF-II, were purified to homogeneity from male rat submandibular glands. 2. The mol. wts of EGF-I and -II were estimated to be 5200 and 5400, respectively, both of them having an apparent biological activity. 3. The antiserum against EGF-II strongly cross-reacted with EGF-I; however, it did so only slightly with mouse or human EGF. 4. EGF was detected by radioimmunoassay in various tissues of male and female rats, and the concentrations of rat EGF in the submandibular gland, parotid gland, sublingual gland, and liver were significantly higher in the male than in the female.

Animals↗