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Biomedical subjects

K Iwatsuki

Publications and source records attributed to K Iwatsuki.

At least 199 records · Page 11Linked to original sources
PubMed1984

Inhibitory action of thyrotropin-releasing hormone on serum amylase activity and its mechanism.

The effect of im administration of 500 micrograms TRH on serum amylase activity was studied in 34 normal women, 6 women with primary hypothyroidism, 1 woman with anorexia nervosa, 6 women with hyperthyroidism due to Graves' disease, and 5 women with renal failure on chronic hemodialysis. Serum amylase activity decreased significantly in 31 of 34 normal subjects 60 to 120 min after administration of TRH. However, amylase isoenzymes were not significantly affected after administration of TRH, suggesting that TRH equally affects pancreatic and salivary amylase activity. TRH was also effective in patients on chronic hemodialysis, indicating that TRH does not reduce serum amylase activity by increasing urinary excretion of amylase. Since TRH reduced serum amylase activity in hyperthyroid patients in whom TRH failed to stimulate TSH secretion, TRH does not reduce serum amylase activity through increased secretion of TSH. The action of TRH was not mediated by serum thyroid hormone levels since TRH was similarly effective in patients with hypothyroidism or hyperthyroidism. TRH did not inhibit or interfere with amylase determination when added in vitro to heparinized blood. Perfusion of the dog pancreas with TRH reduced amylase activity in pancreatic juice and pancreatic venous blood. The magnitude of the decrease was related to the dose of TRH used. Since decrease in amylase activity of the pancreatic juice preceded that in pancreatic venous blood, TRH probably directly acts on the pancreas to reduce amylase secretion. As a result, serum amylase activity decreased after administration of TRH.

Amylases↗
PubMed1984

Pustulosis vegetans.

Sterile pustules and crusted vegetative plaques on the trunk and limbs developed in a 24-year-old man. They left cribriform scars after healing. Histologically, the lesions showed epidermal proliferation and pustulosis resembling that found in "pyoderma vegetans" and pemphigus vegetans. The lesions were effectively suppressed in two months by the topical application of methoxsalen followed by UV-A irradiation. Studies revealed that the chemotactic activity of polymorphonuclear leukocytes (PMNs) in the patient's peripheral blood was enhanced and that an extract of lesional crusty scales showed the presence of a PMN chemotactic factor. This factor had a molecular weight near 12,500 daltons similar to that reported in psoriasis scales. We speculate that tissue destruction due to complement activation, possibly induced by immune complex-mediated reactions in the dermis, provoked a process of transepithelial elimination of the inflammatory products.

Adult↗
PubMed1984

Unilateral ashy dermatosis occurring in a child.

An unusual case of ashy dermatosis of Ramirez occurred in a 5-year-old-girl who had ash-colored hyperpigmented macules and plaques on the left leg and the left side of the trunk. These unilateral lesions showed histopathologic changes of a lichenoid tissue reaction. Although the exact cause of ashy dermatosis remains unknown, the positive test result for serum rheumatoid factor and the granular deposition of IgM at the dermoepidermal junction found in our case has immunologic implications.

Child, Preschool↗
PubMed1983

Effects of dopamine on exocrine secretion and cyclic nucleotide concentration in the dog pancreas.

The effects of intravenous injection of dopamine on pancreatic exocrine secretion and on pancreatic cyclic AMP and cyclic GMP concentrations of mongrel dogs were compared with the effects of secretin and pancreozymin. Dopamine (1--10 micrograms/kg), secretin (0.03--0.3 units/kg) and pancreozymin (0.1--1 units/kg) increased exocrine secretion dose dependently, Sulpiride (0.3--1 mg/kg) and yohimbine (0.3--1 mg/kg), D2-receptor antagonists, inhibited the dopamine-induced exocrine secretion dose-dependently but did not inhibit the secretin- or pancreozymin-induced secretion. Secretin (0.3 units/kg) increased cyclic AMp concentration by about 50% but did not affect cyclic GMP concentration. Pancreozymin (1 unit/kg) slightly increased cyclic AMp concentration but markedly increased cyclic GMP concentration by about 50%. However, dopamine (10 micrograms/kg) increased neither cyclic AMP nor cyclic GMP concentration. These results suggest that dopamine causes exocrine secretion from the dog pancreas through D2-receptors which are not linked to adenylate cyclase.

Animals↗
PubMed1983

Profile of anti-stratum corneum autoantibodies in psoriatic patients.

Using autologous normal skin and freshly separated sera, the titers of circulating anti-stratum corneum (SC) IgG autoantibodies, which were predominantly demonstrated by ordinary indirect immuno-fluorescence (IF), and those of complement-fixing anti-SC autoantibodies were compared in 16 psoriatic patients with active lesions, 16 patients with nonpsoriatic inflammatory dermatoses, and 11 normal subjects. As in patients with other inflammatory dermatoses, the titers of IgG anti-SC autoantibodies in psoriatic patients were not specifically higher than in normal controls but were more variable, indicating that their circulating levels are dependent on a delicate balance between consumption at inflammatory sites and a secondary increase due to SC-antigen release following inflammation. The titers of complement-fixing anti-SC autoantibodies were much higher than those of IgG autoantibodies in most cases but they were not particularly high in psoriatic patients. From these findings, we think that if these autoantibodies are really involved in complement activation in inducing the transepidermal leukocyte migration of psoriatic lesions, a local factor of psoriatic epidermis, which may facilitate the permeation of these antibodies toward the SC, plays a more important role than the actual circulating antibody levels.

Adult↗
PubMed1983

Subcorneal pustular dermatosis with vesiculo-bullous eruption. Demonstration of subcorneal IgA deposits and a leukocyte chemotactic factor.

We report an unusual case of subcorneal pustular dermatosis with widespread vesiculobullous lesions. Reduction of the oral prednisone dosage provoked a severe exacerbation, with erythroderma associated with massive pustule formation. This was effectively controlled by topical PUVA. Subsequent recurrence of skin lesions responded well to oral etretinate. Investigation revealed intercellular IgA deposits at the upper epidermis of the paralesional skin, but no circulating antibodies were detected. Characterization of the chemotactic activity of the soluble components of the scales revealed the presence of a 12,000 molecular weight leukotactic factor resembling that found in psoriasis. Furthermore, the vesicle fluid showed only this chemotactic factor, indicating that it may be a major factor in the pathogenesis of subcorneal pustules.

Chemotactic Factors↗
PubMed1983

Cardiovascular effects of dobutamine, dopamine and isoproterenol on the whole animal and isolated cross-perfused atrium in dogs.

The right atrium of the dog was isolated and cross-perfused with arterial blood of another (donor) dog anesthetized with pentobarbital. When dobutamine, dopamine or isoproterenol was administered intravenously to the donor dog, the following changes were elicited in them: Dobutamine caused slight biphasic changes in heart rate. Dopamine induced biphasic changes in blood pressure and heart rate. Isoproterenol produced a decrease in blood pressure and a marked increase in heart rate. All these 3 catecholamines, however, induced positive chronotropic and inotropic effects in a similar fashion on the isolated atrium cross-perfused with blood of the donor dog. When injected into the cannulated sinus node artery of the isolated dog atrium, dobutamine, dopamine or isoproterenol induced monophasic positive chronotropic and inotropic effects in a dose-related manner, although the potency of each of the drugs was different. Dobutamine-induced effects were abolished by propranolol, but not modified by imipramine which suppressed significantly tyramine- and dopamine-induced effects. The difference in dobutamine-induced chronotropic effect between the whole animal and the isolated atrium may be due mainly to modification by extracardiac factors in the whole animal.

Animals↗
PubMed1983

Effect of acebutolol on plasma catecholamine concentrations in anesthetized dogs with ouabain-induced arrhythmias and its direct actions in vitro on the adrenal medulla.

We have performed studies on blood hormone dynamics following intravenous administration of acebutolol, a newly synthesized beta-blocker, and its direct action on the adrenal medulla in vitro. Intravenous injection of acebutolol into anesthetized dogs almost doubled the plasma adrenaline and noradrenaline concentrations within 5 to 15 minutes, while renin activity was reduced to approximately two-thirds of the pre-administration level. When arrhythmia was induced in dogs with ouabain, the plasma adrenaline and noradrenaline levels increased to 220 +/- 109 and 392 +/- 84 pg/ml, respectively, from the basal levels of 44 +/- 24 and 140 +/- 43 pg/ml. The restoration of sinus rhythm following the administration of acebutolol was accompanied by a further increase in the plasma adrenaline and noradrenaline levels to 797 +/- 364 and 1226 +/- 263 pg/ml, respectively. A perifusion experiment indicated that acebutolol directly accelerated catecholamine release from the adrenal medulla in pigs.

Acebutolol↗
PubMed1983

Induction of leukocyte adherence at the basement membrane zone with subsequent activation of their metabolic pathway by pemphigoid antibodies and complement.

We observed in our in vitro studies that human leukocytes were attached by their complement receptors to the basement membrane zone (BMZ) of the skin specimens pretreated with pemphigoid antibodies and complement. The resultant histologic feature was very similar to that of an early stage of the inflammatory reactions observable in the lesions of bullous pemphigoid. Eosinophils were also attracted to the BMZ in proportion to their number in cell suspensions, but the adhesion of eosinophils occurred neither selectively nor excessively. The nitroblue tetrazolium (NBT) test, which was carried out after the leukocyte attachment test, demonstrated that only those leukocytes bound specifically to the BMZ incorporated NBT dye complexes vigorously to form formazan crystals in their cytoplasms. The present studies showed that complement-fixing anti-BMZ antibodies induce enhancement of leukocyte activities as well as immune adherence to the BMZ, indicating that the enhanced leukocyte function plays a role in the separation between epidermis and dermis in bullous pemphigoid.

Antibodies↗
PubMed1983

Pemphigus antibodies mediate the development of an inflammatory change in the epidermis. A possible mechanism underlying the feature of eosinophilic spongiosis.

The interaction between complement-fixing pemphigus antibodies and leukocytes was investigated by the in vitro leukocyte attachment test. Attachment of eosinophils as well as neutrophils was induced by pemphigus antibodies at the intercellular space of epidermis in the presence of complement. This phenomenon was found to be produced by 7 out of 10 pemphigus sera in the indirect method using non-lesional skin as a substrate, and in 2 out of 7 biopsy specimens taken from perilesional skin without addition of any sera by the direct method. Those leukocytes bound specifically to the epidermis showed an enhanced function. i.e., vigorous incorporation of nitroblue tetrazolium dye complexes and formation of formazan crystals in the cytoplasms. The results of the present studies suggest that complement-fixing pemphigus antibodies mediate the development of an inflammatory change by inducing an infiltration of polymorphs in the epidermis, which is noted as eosinophilic spongiosis histologically.

Antibodies↗
PubMed1983

Reduction of blood pressure and vascular collagen in the spontaneously hypertensive rat by elastase.

The effects of elastase on collagen biosynthesis and deposition in the aorta, heart and liver were investigated in spontaneously hypertensive rats (SHR). Prolyl hydroxylase activity (EC 1.14. 11.2; proline, 2-oxoglutarate dioxygenase) was significantly increased in the aorta of SHR compared with that of control. When elastase (10 mg/kg, i.p.) was given daily to the SHR for 9-weeks, the blood pressure was 175 +/- 6.0 mm Hg (n = 6), whereas the blood pressure of the untreated SHR was increased to 209 +/- 6.4 mm Hg (n = 6). In contrast, elastase did not influence changes in the blood pressure of normotensive rats (WKY). Prolyl hydroxylase activity and hydroxyproline content in the aorta were significantly smaller than those in non-treated SHR. Urinary excretion of hydroxyproline in SHR was increased by treatment with elastase. However, markers of collagen biosynthesis and deposition in the heart and liver in either SHR or WKY were not modified by treatment with elastase. These results suggest that the lowering of blood pressure in SHR treated with elastase may be related to the decrease of vascular collagen biosynthesis and deposition.

Aging↗
PubMed1983

Effects of nitroglycerin on pancreatic exocrine secretion and cyclic nucleotide concentrations of the dog pancreas.

The effects of nitroglycerin on the secretion of pancreatic juice and on the intracellular levels of cyclic nucleotides were investigated in preparations of the isolated, blood-perfused dog pancreas. Nitroglycerin (10-30 micrograms) injected intra-arterially caused a dose-dependent increase in the secretion of pancreatic juice within 30 sec. The concentration of protein in the pancreatic juice induced by nitroglycerin was increased. However, bicarbonate concentration was increased slightly. Nitroglycerin-induced secretion was not modified by pretreatment with phentolamine, propranolol, atropine, metiamide and sulpiride. Nitroglycerin increased cyclic GMP concentration in the pancreatic tissue within 2 min associated with the secretion of pancreatic juice. On the other hand, cyclic AMP concentration was not influenced significantly throughout 30 min after the administration of nitroglycerin. From these results, it is concluded that nitroglycerin may produce an increase in pancreatic secretion mediated through an increase of intracellular cyclic GMP concentration.

Acetylcholine↗
PubMed1983

Effects of hydergine on pancreatic exocrine secretion in the isolated, blood-perfused pancreas of the dog.

The effects of hydergine on the secretion of pancreatic juice in the dog were investigated in preparations of the isolated, blood-perfused pancreas, and compared with those of secretin and dopamine. Hydergine (30-300 micrograms) injected intra-arterially caused dose-dependent increases in the secretion of pancreatic juice after a delay of a few min. The secretory activity of 300 micrograms of hydergine was approximately equal to that of 0.05 units of secretin and 2 micrograms of dopamine. Secretory responses to hydergine were inhibited by treatment with sulpiride, but not inhibited by phentolamine, propranolol, atropine or metiamide. The concentration of bicarbonate in the pancreatic juice induced by hydergine was increased in a dose-dependent manner. However, the protein concentration was scarcely changed. These secretory actions were analogous to those of dopamine. From these results, it is concluded that hydergine mainly stimulates pancreatic secretion by acting on dopaminergic receptors of the dog pancreas.

Animals↗
PubMed1982

Effects of nitroprusside on pancreatic juice secretion in the blood-perfused canine pancreas.

The effects of nitroprusside on the secretion of pancreatic juice were investigated in preparations of isolated and blood-perfused canine pancreas. Nitroprusside (10-30 micrograms/kg) injected intravenously elicited a dose-dependent increase in pancreatic secretion accompanied by a decrease in blood pressure. Intra-arterial administration of nitroprusside (3-300 micrograms) into the perfused pancreas also elicited an increased secretion in preparations of both constant pressure and constant flow perfusion system. The results suggest that nitroprusside-induced pancreatic secretion may not result from the peripheral vasodilatation caused by nitroprusside. The effect of 100 micrograms of intra-arterial nitroprusside corresponded roughly to that of 0.1 units of secretin or 0.3 units of pancreozymin. Nitroprusside-induced secretion was inhibited by the infusion of ethacrynic acid (1 mg/min), but was not modified by phentolamine, propranolol, atropine, haloperidol, tetrodotoxin and metiamide. Nitroprusside produced a dose-dependent increase in the bicarbonate and protein concentrations in the juice, but had little effect on chloride concentration. This action was different from that of secretin or pancreozymin. It is concluded that nitroprusside may produce an increase in pancreatic secretion by acting directly on pancreatic cells, and that this action may be mediated at least in part through the increase of intracellular cyclic GMP concentration.

Animals↗