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Biomedical subjects

H Amano

Publications and source records attributed to H Amano.

At least 235 records · Page 13Linked to original sources
PubMed1985

Involvement of central catecholamines in mediation of pressor responses of the rat to carotid occlusion.

Carotid occlusion evoked a pressor response in rats after transection of the spinal cord. Intraventricular pretreatment with 6-hydroxydopamine inhibited the pressor response. The pressor response to occlusion was also diminished by the intraventricular but not by the intravenous injection of guanethidine. Intravenous atropine or mecamylamine, or intraventricular captopril did not affect the pressor response. Thus, it appears that central catecholaminergic mechanisms are involved in the mediation of the pressor response to carotid occlusion.

Animals↗
PubMed1985

Caudal ventrolateral medulla. A region responsible for the mediation of vasopressin-induced pressor responses.

We localized glutamate-sensitive sites in the ventrolateral medulla of the rat with the spinal cord cut at C. When unilaterally injected into a circumscribed region of the caudal ventrolateral medulla, L-glutamate (30-300 ng) elicited a dose-dependent increase in arterial pressure. The pressor response was accounted for by an increased release of vasopressin because it was abolished by the intravenous injection of a vasopressin antagonist. Bilateral microinjections of kainic acid (50 ng) into the ventrolateral glutamate-sensitive area markedly reduced a vasopressin-induced pressor response to kainic acid (30 ng), injected bilaterally into the nucleus tractus solitarii. It is concluded that the glutamate-sensitive neurons in the caudal ventrolateral medulla are involved in mediation of the vasopressin-induced pressor response arising from the nucleus tractus solitarii.

Animals↗
PubMed1985

Pancreatic sphincterotomy and pancreatic endoprosthesis.

Recently, endoscopic sphincterotomy (EST), developed as a treatment of bile duct stone or papillary stenosis, has been used for transpapillary biliary drainage in cases of extrahepatic biliary stenosis. For the nonoperative treatment of chronic pancreatitis, we have developed this procedure into a technique for opening the pancreatic duct orifice. Pancreatic sphincterotomy was performed successfully in 10 out of 13 cases with chronic pancreatitis and improved the clinical symptoms in 9 cases. Moreover, in 3 cases we succeeded in inspecting the intrapancreatic duct by peroral pancreatoscopy, and in removing stones from the main pancreatic duct in 2 cases in this series, using the basket. Also through the opened pancreatic orifice, a pancreatic endoprosthesis was placed endoscopically into the main pancreatic duct in 3 cases to improve pancreatic drainage. This report discusses method, evaluation, and complications of pancreatic sphincterotomy in the endoscopic treatment of chronic pancreatitis, and describes successful cases of the basket removal of pancreatic stones and the placement of pancreatic endoprosthesis through the opening of the pancreatic orifice.

Adult↗
PubMed1985

Therapeutic effect of a new antibacterial substance ofloxacin (DL8280) on pulmonary tuberculosis.

A new antibacterial substance, ofloxacin (DL8280), was used in the treatment of pulmonary tuberculosis. The agent was given to 19 patients with chronic cavitary lung tuberculosis as single doses of 300 mg daily for 6 to 8 months. A decrease in the amount of tubercle bacilli in the sputum was observed in almost all patients, and negative conversion occurred in 5. Resistance of tubercle bacilli to the agent appeared in patients who did not show negative conversion. No side effects were observed during the administration period. The agent was considered useful in lung tuberculosis therapy.

Adult↗
PubMed1985

Further studies on vasopressin-induced pressor responses to kainic acid injected into the nucleus tractus solitarii of the rat.

Kainic acid, an analogue of L-glutamate, was microinjected into the nucleus tractus solitarii of cordotomized rats. Kainic acid (30 ng) injected bilaterally into the nucleus elicited hypertension. The pressor response to kainic acid was restricted to sites in the intermediate one-third of the nucleus tractus solitarii. Plasma vasopressin levels were markedly increased during the kainic acid-induced pressor response. Intravenous injection of atropine sulphate or mecamylamine, or intraventricular injection of captopril did not affect the pressor response. It is concluded that in cordotomized rats the pressor response to kainic acid injected into the nucleus tractus solitarii is mainly mediated via increased release of vasopressin. It seems unlikely that the central cholinergic and angiotensin mechanisms are mainly responsible for the response to kainic acid.

Animals↗
PubMed1985

[Antiemetic combination of metoclopramide and methylprednisolone for cisplatin-induced vomiting].

An antiemetic combination of metoclopramide and methylprednisolone was administered to 16 lung cancer patients receiving cisplatin (80 cmg/m2) alone or in combination with other drugs. Metoclopramide was administered four times intravenously at a dose of 1.5 mg/kg. Methylprednisolone was administered three times intravenously at a dose of 125 mg. Sixteen patients received a total of 34 chemotherapy courses. No vomiting occurred in 70% of 34 chemotherapy courses and mild emesis (one or two vomiting episodes) occurred in 18% of chemotherapy courses. Side effects were minimal and included mild sleepiness (nine patients), diarrhea (three patients), and hiccups (three patients). It is concluded that a combination of metoclopramide and methylprednisolone is very effective in preventing cisplatin-induced vomiting.

Aged↗
PubMed1984

Vasopressin-induced pressor responses to carotid occlusion in the rat.

We studied the effect of carotid occlusion on blood pressure in cordotomized rats. Occlusion of both common carotid arteries resulted in an increase in blood pressure. This response was unaffected by denervation of the sinus and aortic nerves, and vagi. The response to occlusion was blocked by intravenous administration of a vasopressin antagonist, d(CH2)5Tyr(Me)arginine-vasopressin, but not by intravenous administration of hexamethonium or captopril. Further, microinjection of procaine into the paraventricular nuclei abolished the pressor response to occlusion. Thus, it appears that in cordotomized rats carotid occlusion causes release of vasopressin and this in turn results in an elevation of blood pressure. The arterial baroreceptors are not essential for the pressor response.

Animals↗
PubMed1984

Opioid activity of enkephalin analogues containing the kyotorphin-related structure in the N-terminus.

The pharmacological activity of eight analogues of enkephalin containing L-Arg or D-Arg in position 2 were examined. All peptides showed weaker inhibitory effects than those of naturally-occurring enkephalins on the isolated guinea-pig ileal longitudinal muscle and the mouse vas deferens. On the contrary, these eight peptides were more potent than enkephalins in the analgesic test involving intracisternal administration to mice. By the intravenous route, only D- Arg2 -Met5-enkephalin, which induced a most potent analgesia by intracisternal injection, was effective. D- Arg2 -Met5-enkephalin showed a similar binding affinity to that of Met5-enkephalin in the opioid mu-receptor binding assay, but had a lower delta-receptor binding affinity than did Leu5-enkephalin. Administration of thiorphan , an enkephalin dipeptidyl carboxypeptidase inhibitor, did not potentiate the analgesic effect of D- Arg2 -Met5-enkephalin, whereas it dramatically enhanced the effect of D-Ala2-Met5-enkephalin, when both drugs were administered concomitantly into the cisterna magna of mice.

Analgesics↗
PubMed1984

New development of peroral cholangioscopy--evaluation of double-angle, oblique viewing cholangioscope.

Seven years have passed since the first report on peroral cholangioscopy by Takekoshi and Takagi (1) in Japan. Recently, several types of peroral cholangioscope with a forceps channel have been made for this treatment. However, the success rate of insertion of these instruments into the common bile duct was less than 50%. Therefore, in cooperation with Fuji-Photo-Optical Co. Ltd., we have made a new scope with the aim of facilitating insertion into the bile duct. Using this new scope, called a double-angle, oblique viewing cholangioscope, we obtain good orientation in the duodenum in en-face view and close inspection of the duodenal papilla, which makes possible easier insertion into the common bile duct. This new scope proved useful in basket removal of bile duct stone, or differential diagnosis between stones and carcinoma of the biliary tract.

Adult↗
PubMed1984

Pathogenesis of experimental endolymphatic hydrops.

The protein content and the d.c. potential of the endolymph differs in the various parts of the endolymphatic space (cochlea, utricle, semicircular canals and endolymphatic sac) as also does the ion composition (chloride, potassium, sodium). 12 months after obliteration of the endolymphatic sac and duct in guinea pigs the d.c. potential falls, whereas, the sodium activity increases. The endolymphatic hydrops is not caused by an increased colloid osmotic pressure. The increased water-binding capacity of the cochlear endolymph is correlated with the increased Na+ activity.

Animals↗
PubMed1984

Autonomic nervous system in human palatine tonsil.

The autonomic nervous system in the human palatine tonsil was studied systematically as follows: 1) Using the radio binding assay method, the presence of beta-adrenergic receptors and muscarinic-cholinergic receptors was demonstrated in the tonsil. 2) Using high performance liquid chromatography, the quantity of catecholamines in the tonsillar tissue was determined for the first time. 3) The distributions of sympathetic and parasympathetic nerves in the tonsillar tissue were demonstrated by fluorescence- or enzyme-histochemistry. 4) Cases of habitual tonsillitis were compared with cases of simple tonsillitis concerning the quantities of beta-adrenergic receptors and catecholamines. As a result, the difference in quantity of beta-adrenergic receptors between the two was insignificant, but the quantity of catecholamine was greater in the former.

Adrenergic Fibers↗