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Biomedical subjects

Y Seki

Publications and source records attributed to Y Seki.

At least 91 records · Page 5Linked to original sources
PubMed1995

Vasorelaxant effect of PACAP-27 on canine cerebral arteries and rat intracerebral arterioles.

The vasorelaxant effects of pituitary adenylate cyclase activating polypeptide (PACAP)-27 were examined and compared with those of PACAP-38 and vasoactive intestinal polypeptide (VIP) on isolated canine cerebral arteries and rat intracerebral arterioles in vitro. The addition of PACAP-27, PACAP-38 or VIP resulted in similar concentration-dependent relaxations in both canine basilar arteries and rat intracerebral arterioles. There were regional differences in the PACAP-27-induced relaxations measured in canine cerebral arteries. The maximum relaxation induced by PACAP-27 was significantly lower in the basilar arteries (23.0 +/- 5.6%) than in the rostrally located arteries (proximal middle cerebral arteries: 45.4 +/- 5.7%, anterior cerebral arteries: 55.2 +/- 5.8%). The maximum relaxation induced by PACAP-27 in the basilar arteries was significantly enhanced by mechanical removal of the endothelium (16.4 +/- 4.5% vs. 32.7 +/- 5.8%) as well as by pretreatment with indomethacin or aspirin (12.9 +/- 4.1% vs. 48.7 +/- 6.1% and 46.5 +/- 9.2%, respectively). Incubation of canine cerebral arteries with PACAP-27 in vitro resulted in an increased release of prostaglandin F2 alpha in the buffer from 14.5 +/- 2.1 pg/min/1 mg vessel to 31.1 +/- 4.2 pg/min/1 mg vessel, while other cyclooxygenase cascade metabolites such as prostaglandin E2, thromboxane B2 and 6-keto prostaglandin F1 alpha did not change. These data suggest that the PACAP-27-induced relaxation of canine basilar arteries may be associated with prostaglandin F2 alpha or its precursor, prostaglandin H2.

Animals↗
PubMed1995

Failure of copper incorporation into ceruloplasmin in the Golgi apparatus of LEC rat hepatocytes.

Copper incorporation into ceruloplasmin during ceruloplasmin synthesis was studied by comparing LEC and control rats. Major 132 and 136 kDa ceruloplasmins were found in microsomes and the Golgi apparatus, respectively, isolated from liver homogenates of LEC and control rats. Copper analysis showed that no copper was detected in the ceruloplasmin in the microsomes of either rat. Copper was present in ceruloplasmin in the Golgi apparatus and serum of controls, while it was not detected in ceruloplasmin in the Golgi apparatus and serum of the LEC rat. These results indicate that copper is incorporated into ceruloplasmin in the Golgi apparatus of normal hepatocytes. LEC rats fail to incorporate copper into ceruloplasmin in the Golgi apparatus.

Animals↗
PubMed1995

The effects of pituitary adenylate cyclase-activating polypeptide on cerebral arteries and vertebral artery blood flow in anesthetized dogs.

We investigated and compared the effects of pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) on cerebral circulation in anesthetized dogs. The intracisternal administration of PACAP-27, PACAP-38, and VIP dilated canine cerebral arteries in a dose-dependent manner. A 10 nmol dose of PACAP-27, PACAP-38, and VIP dilated the basilar artery by 23 +/- 3, 27 +/- 3 and 30 +/- 3%, respectively. Rostrally located arteries tended to be more responsive to PACAP-27. Pretreatment with NG-monomethyl-L-arginine did not affect PACAP-27-induced vasodilation. Vertebral artery blood flow was also affected by intra-arterial injection of these peptides in a dose-dependent manner. A 100 pmol dose of PACAP-27, PACAP-38, and VIP increased the vertebral artery blood flow by 42 +/- 10, 29 +/- 4, and 62 +/- 11%, respectively. The VIP receptor antagonist, [Lys1,Pro2,5,Arg3,4,Tyr6]VIP, inhibited both the VIP- and PACAP-38-induced increase in vertebral artery blood flow. These findings suggest that PACAP plays a role in the regulation of cerebral circulation.

Anesthesia↗
PubMed1995

Sustained activation of blood coagulation in patients with cerebral thrombosis.

Recent progress in the measurements of the hemostatic markers enables us to assess the detailed profiles of hemostatic activation in various diseases. To evaluate the degree of hemostatic system activation in patients with cerebral thrombosis, detailed coagulation studies were performed in 28 patients with acute-phase cerebral thrombosis and in 36 with chronic-phase cerebral thrombosis, together with 6 with chronic-phase cerebral hemorrhage and 37 age-matched healthy volunteers. In both acute-phase and chronic-phase cerebral thrombosis, plasma levels of thrombin-antithrombin III complex, plasmin-alpha 2-plasmin inhibitor complex and D-dimer were significantly higher, and antithrombin III and protein C were significantly lower than those in the normal group. Plasma fibrinogen concentration was significantly higher in chronic-phase cerebral thrombosis than that in chronic-phase cerebral hemorrhage. No significant difference was found in these variables between acute-phase and chronic-phase cerebral thrombosis. In addition, there was no difference in these parameters between chronic phase cerebral hemorrhage and normal subjects. These findings indicate that a sustained activation of coagulation and fibrinolysis is present in cerebral thrombosis, and it might contribute to the pathogenesis of cerebral thrombosis.

Acute Disease↗
PubMed1995

Lighted mirror for microneurosurgery.

We describe a newly developed, lighted mirror that provides enough luminous intensity to obtain a clear image in deep operative fields under high magnification. Through the initial neurosurgical procedures in which it was tested, the mirror proved particularly useful for inspecting the ventral aspect of the fifth nerve in a microvascular decompression for trigeminal neuralgia, and for observing the fundus of the internal auditory meatus after removal of an acoustic neuroma to ensure no residual tumor.

Humans↗
PubMed1995

Myofibroma of the mandible. Clinicopathologic study and review of the literature.

A case of mandibular myofibroma in a 2-month-old boy is presented. Including this case, 24 pediatric and 11 adult patients with maxillofacial myofibroma have been reported since 1981. Of the 24 pediatric patients, 15 (62.5%) had lesions affecting the mandible. The adult cases had no mandibular involvement. Histologic evaluation of the tissue specimen revealed an interlacing pattern of spindle-shaped cells with long oval nuclei. Tissue immunohistochemical staining found it to be reactive for antibodies directed against vimentin and alpha-smooth muscle actin, but not desmin, S-100 protein, neuron-specific enolase, or myoglobin. Electron microscopy examination revealed the following cells: myofibroblast-like cells, fibroblast-like cells, and intermediate cells that were similar to the fibroblast-like cells except for the presence of a few microfilaments. Myoblast-like cells were not seen.

Actin Cytoskeleton↗
PubMed1995

Effects of adrenomedullin, calcitonin gene-related peptide, and amylin on cerebral circulation in dogs.

The effect of human adrenomedullin on cerebral circulation was investigated in dogs in vivo and in vitro. Bolus administration of adrenomedullin or its homologous peptides, calcitonin gene-related peptide (CGRP) and amylin, into the vertebral artery induced a dose-dependent increase in vertebral blood flow. The potencies of adrenomedullin and CGRP were similar and approximately 100 times more than that of amylin. The effects of adrenomedullin and CGRP were inhibited by CGRP8-37, an antagonist of CGRP. In contrast to substance P, adrenomedullin did not induce an increase in blood flow after prior administration of CGRP. Pretreatment with either NG-nitro-L-arginine methyl ester or indomethacin did not affect the adrenomedullin-induced increase in blood flow. Intracisternal administration of adrenomedullin induced dilation of the basilar and other major cerebral arteries in a dose-dependent manner, accompanied by an increase in the concentration of cyclic AMP in the cerebrospinal fluid. Adrenomedullin also induced relaxation of isolated basilar and middle cerebral arterial rings. These data suggest that adrenomedullin induces vasodilation of cerebral arteries and an increase in vertebral blood by acting at CGRP receptors positively coupled to adenylate cyclase, and that these effects are not dependent on nitric oxide or prostaglandin formation.

Adrenomedullin↗
PubMed1995

Central cardiovascular effects induced by intracisternal PACAP in dogs.

The cardiovascular responses to intracisternally administered pituitary adenylate cyclase-activating polypeptide (PACAP) were investigated and compared with those of vasoactive intestinal peptide (VIP) in anesthetized dogs. Intracisternal administration of 10 nmol of PACAP-27 increased mean arterial blood pressure (MABP) significantly with a simultaneous increase of plasma arginine vasopressin and epinephrine concentrations. Intracisternal administration of VIP increased plasma arginine vasopressin concentration significantly but caused no appreciable change in MABP. Systemic infusion of the nonpeptide vasopressin V1 receptor antagonist OPC-21268 did not inhibit the PACAP-27-induced increase in MABP, whereas phentolamine, an alpha-adrenoceptor blocker, reversed the increase. Intracisternal pretreatment with the vasopressin V1 receptor antagonist [Pmp1, Tyr(Me)2]Arg8-vasopressin also inhibited the increase. These findings suggest that PACAP has a central pressor action by increasing sympathetic outflow, which is probably mediated by the vasopressinergic neural network. PACAP seems to play important roles in hormonal and neural control of systemic circulation.

Adrenergic alpha-Antagonists↗
PubMed1995

[Persistent discrepancy between FDP and D-dimer in a patient with acute leukemia].

In a patient with acute myeloblastic leukemia, serum fibrinogen/fibrin degradation products (FDP) were markedly elevated to 54.91 micrograms/ml, but plasma D-dimer was only slightly elevated (1.44 micrograms/ml). FDP in plasma measured by a method using monoclonal antibody specific to FDP was less than 5 micrograms/ml. Gradual reduction of blastic cells was obtained with the therapy of low-dose cytarabine, G-CSF and etoposide. The serum FDP increased up to 71.74 micrograms/ml accompanied with a transient elevation of D-dimer, and subsequently declined without any anticoagulant therapy. However, a discrepancy between serum FDP and plasma D-dimer lasted for a long time. In this case persistent acceleration of coagulation and fibrinolysis which may result in the elevation of serum FDP was not observed, suggesting that the greater part of increased FDP didn't reflect the true FDP formed by plasmin. There were possibilities that elevated serum FDP values were also caused by the presence of soluble fibrin, unclottable fibrinogen and the degradation products by nonplasmic proteinases. Simultaneous measurements of FDP and D-dimer are useful for a more accurate evaluation of hyperfibrinolytic states and to avoid possible misinterpretations due to falsely positive FDP.

Aged↗
PubMed1995

[Lead].

Explore the source record for details and available documents.

Humans↗
PubMed1994

Tissue factor in plasma of patients with disseminated intravascular coagulation.

Recently it has been shown that tissue factor (TF), an important trigger for initiating blood coagulation, is present in the circulating plasma. In order to assess the clinical implications of TF in plasma, plasma concentration of TF was quantitated in 65 patients with disseminated intravascular coagulation (DIC). The mean concentration of plasma TF was elevated in patients with DIC at presentation as compared with healthy subjects (446 +/- SD 536 pg/ml vs. 138 +/- 51 pg/ml, P < 0.001). Abnormally high levels were found only in 46.2% of the patients, predominantly in patients with non-hematological solid tumors and acute leukemia. Plasma TF did not correlate with hemostatic markers of DIC such as thrombin-antithrombin III complex, prothrombin fragment 1 + 2, plasma-alpha 2-plasmin inhibitor complex, FDP, D-dimer, or fibrinogen. Serial determinations of plasma TF demonstrated that plasma TF changes roughly in parallel with the course of DIC in most patients with elevated TF at presentation of DIC. These findings suggest that plasma TF is potentially valuable for monitoring the progress of DIC in a limited population of patients.

Disseminated Intravascular Coagulation↗
PubMed1994

Dural arteriovenous malformations in the anterior cranial fossa.

Two cases of dural arteriovenous malformation (DAVM) fed by the anterior ethmoidal artery in the anterior cranial fossa are reported, one of them examined by magnet resonance imaging (MRI). Only one other case with MRI findings so far has been published. Fourty-eight previously reported cases are reviewed. One of our patients presented with subdural haematoma (SDH) without subarachnoid or intracerebral haemorrhage. The other patient had a nasal bleed without any neurological manifestations. In comparison with previously reported cases, the clinical manifestation of our cases is infrequent (1 patient with nasal bleed, and 2 patients with pure SDH that is 2 and 4%, respectively, in the literature). Feeder was the anterior ethmoidal artery either unilateral or bilateral. Drainage of DAVMs was through a markedly dilated vascular sac into the superior sagittal sinus (SSS). The high incidence of haemorrhage from DAVM in the anterior fossa is related to this vascular sac. Magnetic resonance imaging (MRI) showed a flow void area in the left frontal region on T 1-weighted images in one case. These cases were treated by surgical excision of the malformation with good results. Aetiology, clinical presentation, and treatment of these rare DAVMs in the anterior cranial fossa is discussed.

Cerebral Angiography↗
PubMed1994

Immaturity of the myenteric plexus is the aetiology of meconium ileus without mucoviscidosis: a histopathologic study.

The most common aetiology of meconium ileus is a deficiency in trypsin activity caused by cystic fibrosis. The pathogenesis of meconium ileus without mucoviscidosis is less well understood, although a number of causative factors have been suggested. The symptoms and clinical course of nine patients with meconium ileus without mucoviscidosis were reviewed, and the myenteric plexus of a surgical specimen of intestine was examined histologically and cytometrically. The nuclei of the intramural ganglion cells were much smaller than were seen in normal newborn infants. The nuclear areas resembled those seen in fetuses of 5-6 months gestational age, but the number of ganglion cells approached normal. This immaturity of the ganglia was observed both in the contracted distal ileum and dilated proximal ileum. Patients with an ileostomy passed solid faeces for about 1 to 2 months postoperatively, after which time the faeces became watery. The intramural ganglia were mature at the time of ileostomy closure. We conclude that immaturity of the myenteric plexus in the ileum and colon seems to be the main aetiologic factor in meconium ileus without mucoviscidosis.

Cytodiagnosis↗
PubMed1994

Extensive dissection at the porta hepatis for biliary atresia.

Dissection at the porta hepatis is the crucial step in surgery for biliary atresia. The authors describe their procedure for extensively dissecting the porta hepatis. The technique is based on an anatomic cast corrosion of the human liver, and the portal vein serves as the landmark for dissection. Lateral dissection at the hepatic hilus is critical to the procedure. On the right side, the anterior portal branches are dissected to the bifurcation of the S5 and S7 segmental portal branches, over the bifurcation of the anterior and posterior portal branches. On the left side, the liver parenchyma, which bridges the umbilical point, is sectioned, and the left portal branch is dissected to the umbilical point over the pars transversalis and taped. The fibrous mass that lies within the confines of the portal branches, including the dorsal aspect, is transected completely. This procedure was performed in 16 infants; the jaundice cleared in 93.7%.

Biliary Atresia↗
PubMed1994

Bilateral periorbital eccrine hidrocystoma.

We saw four patients showing identical features as cystic lesions on the bilateral external canthi. Histological examination showed cystic cavities in the dermis. Histological and enzyme histochemical findings suggest that these cystic tumors are of eccrine origin. Thus we diagnosed these cystic tumors as eccrine hidrocystoma with characteristic clinical feature. The recognition of this feature would help to correctly diagnose these eccrine hidrocystoma.

Adult↗
PubMed1994

Cough variant asthma: a case study with antigen, histamine and methacholine inhalation challenge tests.

This paper presents a 7 year old girl with cough variant asthma, in which house dust challenge test provoked fine crackles on auscultation without any changes of lung function test. Pretreatment with DL-chlorpheniramine maleate for 7 days inhibited the appearance of fine crackles. On histamine inhalation test, fine crackles and rhonchi appeared on auscultation without bronchoconstriction (% fall of one-second forced expiratory volume < 10%). These data suggest that the cause of cough variant asthma is mainly an immunoglobulin E-mediated allergic reaction in the mucus secreting system.

Asthma↗