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Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 325 records · Page 18Linked to original sources

Endogenous adenosine inhibits P-selectin-dependent formation of coronary thromboemboli during hypoperfusion in dogs.

The activation of platelets and the formation of neutrophil- platelet conjugates may lead to the development of thromboemboli. We studied whether blockade of adenosine receptors during coronary hypoperfusion may cause thromboemboli via P-selectin-dependent mechanisms in 30 open-chest dogs. When coronary blood flow was reduced to 20% of the control, it was stable at low levels with increases in adenosine levels. When 8-p-sulfophenyltheophylline, an adenosine receptor antagonist, was infused during coronary hypoperfusion, coronary blood flow decreased gradually and approached almost zero 20 min after its administration. Histological examination revealed thromboemboli in the small coronary vessels. During hypoperfusion in the presence of 8-p-sulfophenyltheophylline, the mAb against P-selectin attenuated both the reduction in coronary blood flow and the formation of thromboemboli, and improved contractile and metabolic dysfunction of the myocardium. Flow cytometric analysis indicated that the expression of P-selectin on platelet and neutrophil-platelet adhesion were increased during coronary hypoperfusion, and that both were further augmented by 8-p-sulfophenyltheophylline. Immunohistochemical examination showed no staining of P-selectin in the ischemic myocardium. Adenosine inhibited the thrombin-induced expression of P-selectin on platelet and neutrophil- platelet adhesion via adenosine A2 receptors. Adenosine appears to inhibit the formation of thromboemboli during coronary hypoperfusion by suppressing the expression of P-selectin on platelets and neutrophil-platelet adhesion.

Adenosine↗

Adrenomedullin increases intracellular Ca2+ and inositol 1,4,5-trisphosphate in human oligodendroglial cell line KG-1C.

The effects of adrenomedullin (AM), a hypotensive peptide, were investigated in cultured human oligodendroglial cell line KG-1C. Human AM increased the intracellular Ca2+ concentration ([Ca2+]i) at concentrations greater than 10(-7) M. Human calcitonin gene-related peptide (CGRP), a peptide structurally related to AM, also increased [Ca2+]i with a potency similar to that of AM. AM increased [Ca2+]i in the absence of extracellular Ca2+. Further, AM increased inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) level in a concentration-dependent manner similar to that of AM-induced [Ca2+]i, suggesting that AM-induced elevation of [Ca2+]i is due to Ca2+ release from Ins(1,4,5)P3-sensitive stores. AM (10(-9) to 10(-6) M) increased cAMP in a concentration-dependent manner. Forskolin also increased cAMP, but did not mimic the [Ca2+]i-raising effect of AM. These findings suggest that functional AM receptors are present in oligodendroglial KG-1C cells and that AM increases [Ca2+]i through a mechanism independent of cAMP.

Adrenomedullin↗

Activation of inwardly rectifying K+ channels by GABA-B receptors expressed in Xenopus oocytes.

In Xenopus oocytes coinjected with poly(A)+ RNA derived from the rat cerebellum and cRNAs for the cloned G protein-gated inwardly rectifying K+ channel (GIRK), GIRK1 and GIRK2, the GABA-B agonist baclofen elicited inwardly rectifying K+ currents. The inward K+ currents elicited by baclofen were inhibited by the selective GABA-B antagonists 2-OH saclofen and CGP 35348, and by the GIRK inhibitor Ba2+. In contrast, baclofen caused no currents in oocytes injected with the cerebellar poly(A)+ RNA alone, the poly(A)+ RNA and cRNA for GIRK1 or GIRK2, or only cRNAs for GIRK1 and GIRK2. These findings indicate that GABA-B receptors in the rat cerebellum were functionally expressed in Xenopus oocytes and activated the cloned GIRKs composed of GIRK1 and GIRK2 as heteromultimers.

Animals↗

ESR spectroscopy for analysis of hippocampal elimination of a nitroxide radical during kainic acid-induced seizure in rats.

To analyze the balance between free radical production and elimination during seizure, techniques were developed to monitor the sequential changes in the level of an exogenous free radical by ESR in the brains of freely moving rats given kainic acid (KA) to induce seizures (n = 6) and control rats given saline (n = 6). The hippocampus of each rat was perfused with a nitroxide radical solution for 120 min by in vivo microdialysis. Then an intraperitoneal injection of KA or the physiological saline was given to each rat, and the perfusate was changed to Ringer's solution. ESR analysis of sequential samples of dialysate taken after injection revealed an exponential decay in signal amplitude. The median half-life of the nitroxide radical was significantly longer in the KA-treated group than in the control group (P < 0.01). This finding demonstrates a decreased capacity of the hippocampus to eliminate the nitroxide radical from the extracellular space during seizure and may help clarify the mechanism of neuronal cell vulnerability to free radicals during insult or degeneration.

Animals↗

Amygdalar injection of FeCl3 causes spontaneous recurrent seizures.

Rats were microinjected with a 100 mM aqueous solution of ferric chloride into the left amygdaloid body. Behavior was observed and depth electroencephalograms were recorded over the 30 days following injection. All of the FeCl3-injected rats developed isolated epileptiform discharges from the ipsilateral amygdala soon after injection. Within 5 days epileptiform discharges were arising as well from the contralateral amygdala and behavioral seizures were observed. These spontaneous seizures occurred in a pattern associated with stage 4 kindling, with rearing and bilateral forelimb clonus. Seizures persisted during the 30 days of the experiment. Recording from chronically implanted depth electrodes showed development of spike discharges, with recurrent seizures arising from amygdalar regions with propagation into both hippocampi. Aqueous iron is known to initiate lipid peroxidation by free radical mechanisms. Our observations suggest that epileptogenesis followed by chronic, spontaneous seizures could be initiated by deposition of iron-containing compounds into limbic structures of the rat.

Amygdala↗

Inhibition of angiotensin-converting enzyme increases the nitric oxide levels in canine ischemic myocardium.

Since angiotensin-converting enzyme (ACE) produces angiotensin II in the heart, ACE inhibitors may prevent coronary vasoconstriction and increase coronary blood flow. On the other hand, since ACE inhibitors also inhibit kininase II which results in reduced degradation of bradykinin, ACE inhibitors may increase cardiac nitric oxide (NO) levels via stimulation of bradykinin receptors. This study was undertaken to test whether ACE inhibitors increase the cardiac NO levels and coronary blood flow in the ischemic myocardium. In 34 open-chest dogs, the left anterior descending coronary artery was perfused through an extracorporeal bypass tube from the left carotid artery. When either imidaprilat or cilazaprilat of 3 microg/kg/min was infused into the bypass tube for 10 min after reduction of coronary blood flow due to partial occlusion of the bypass tube, coronary blood flow increased from 31 +/- 1 to either 45 +/- 5 or 43 +/- 4 ml/100 g/min despite no changes in coronary perfusion pressure (43 +/- 2 mmHg). During an infusion of either imidaprilat or cilazaprilat, bradykinin and the end-products of NO (nitrate + nitrite) concentrations of coronary venous blood were markedly increased, which were attenuated by either HOE-140 (an inhibitor of bradykinin receptors) or by N(omega)-nitro-L-arginine methyl ester (an inhibitor of NO synthase). We also observed increases in cardiac bradykinin and NO levels due to either imidaprilat or cilazaprilat in the low constant coronary blood flow condition. It is concluded that ACE inhibitors can increase cardiac NO levels via the accumulation of bradykinin in the ischemic myocardium.

Angiotensin-Converting Enzyme Inhibitors↗

A case report of immunotherapy on a patient with advanced gastric cancer by adoptive transfer of OK-432-reactive HLA-matched allogeneic lymphocytes.

Adoptive immunotherapy (AIT) for non-hematological malignancies, using HLA-matched donor lymphocytes, has been rarely reported. For a 35-year-old male patient with peritoneal disseminated advanced gastric cancer, we performed AIT using lymphocytes from his HLA-matched 37-year-old brother and a streptococcal preparation, OK-432, as an antigen. After the donor had been immunized by intradermal administration of OK-432, OK-432-reactive lymphocytes were induced in vitro and transferred to the patient intravenously with OK-432. Low-dose systemic immunochemotherapy, using interleukin-2, 5-fluorouracil and cyclophosphamide, was concurrently administered with AIT. As a result, the Schnitzler metastasis in the patient reduced in size without any significant graft-versus-host-related complications. One of the effector mechanisms of therapeutic benefit was suggested to be cytokine release from the transferred OK-432-reactive lymphocytes. Our findings suggest the safety and efficacy of AIT using lymphocytes from an HLA-matched sibling and OK-432 as an antigen. Further studies to investigate the use of tumor-associated antigen and an HLA-matched sibling's lymphocytes for AIT of advanced cancer are warranted.

Adenocarcinoma, Scirrhous↗

Islet-cell hyperplasia causing hyperinsulinemic hypoglycemia in an adult.

We report a patient, a 23-year-old man, who had clinical and laboratory findings suggestive of insulinoma. Although imaging studies did not reveal any tumors in the pancreas, distal pancreatectomy was performed because the possibility of small insulinoma could not be completely excluded. Grossly, the surgically removed pancreas did not reveal any tumors. Microscopically, the pancreas exhibited islet cell hyperplasia and nesidioblastosis. To our knowledge, this is the first authentic reported case of islet-cell hyperplasia occurring in a Japanese adult.

Adult↗

Two-stage repair for aortic regurgitation with interrupted aortic arch.

We performed two-stage repair for a rare adult case of interrupted aortic arch with aortic regurgitation and sinus of Valsalva aneurysm. A lateroisthmic bypass was established with minimal thoracotomy and partial clamping of the descending aorta to preserve collateral circulation. This was followed by aortic root reconstruction with a prosthetic graft and valve for aortic regurgitation with sinus of Valsalva aneurysm. This less invasive two-stage repair for such a rare pathology may facilitate smooth recovery of the patient.

Adult↗

Laparoscopic splenopexy for pediatric wandering spleen.

Wandering spleen is an uncommon condition, showing a splenic hypermobility that results from laxity or maldevelopment of its suspensory ligament. This condition results in constant danger of splenic torsion and infarction. Wandering spleen was diagnosed in a 2-year-old girl who complained of intermittent abdominal pain, and viability of the spleen was confirmed by doppler ultrasound scan. Elective laparoscopic splenopexy was performed by anchoring the spleen wrapped in absorbable mesh. To our knowledge, this is the first reported case of laparoscopic splenopexy for wandering spleen. The authors believe that this approach is a safe and effective procedure for wandering spleen with the advantage of minimally invasive surgery.

Child, Preschool↗

Median raphe (parameatal) cysts of the penis.

PURPOSE: Although median raphe cysts of the penis have been widely reported the pathogenesis is obscure. We describe the microstructural detection of 3 cases of median raphe to study the true pathogenesis. MATERIALS AND METHODS: Three patients presented to our clinic of plastic surgery complaining of abnormal shape of the penis or mass recurrence. High magnification light microscopy and electron microscopy were performed. RESULTS: Microstructural study revealed that all 3 cases had similar findings to those of the common urethral mucosa. CONCLUSIONS: Median raphe cysts are derived from the external paraurethral ducts and contain features that to our knowledge have not been previously reported.

Adolescent↗

Significance of chromosomal alterations and mutations of the N-RAS and TP53 genes in relation to leukemogenesis of acute myeloid leukemia.

We examined chromosomes and mutations of the N-RAS and TP53 genes in 73 patients with acute myeloid leukemia (AML). Twenty-six patients showed a reciprocal chromosomal translocation or an inversion, and 34 patients showed only unbalanced aberrations. Balanced aberrations were predominantly detected in the AML patients who did not have myelodysplasia, preceding myelodysplastic syndrome, and a history of chemotherapy or radiation therapy. In contrast, unbalanced aberrations were more frequently seen in the patients with AML with trilineage myelodysplasia, AML transformed from MDS, and therapy-related AML. Twenty-two mutations of the N-RAS and TP53 genes were detected, and these mutations were frequently associated with unbalanced chromosomal aberrations. Furthermore, the spectrum of mutations was suggestive of an exposure to alkylating chemicals.

Acute Disease↗

Glutamate receptors: brain function and signal transduction.

Glutamate receptors are important in neural plasticity, neural development and neurodegeneration. N-methyl-d-aspartate (NMDA) receptors and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptors act as glutamate-gated cation channels, whereas metabotropic receptors (mGluRs) modulate the production of second messengers via G proteins. Molecular studies from our and other laboratories indicated that NMDA receptors and mGluRs exist as multiple subunits (NMDAR1 and NMDAR2A-2D) and multiple subtypes (mGluR1-mGluR8). In light of the molecular diversity of glutamate receptors, we explored the function and intracellular signaling mechanisms of different members of glutamate receptors. In the visual system, retinal bipolar cells receive glutamate transmission from photoreceptors and contribute to segregating visual signals into ON and OFF pathways. The molecularly cloned mGluR6 is restrictedly expressed at the postsynaptic site of ON-bipolar cells in both rod and cone systems. Gene targeting of mGluR6 results in a loss of ON responses without changing OFF responses and severely impairs detecting visual contrasts. Since AMPA receptors mediate OFF responses in OFF-bipolar cells, two distinct types of glutamate receptors effectively operate for ON and OFF responses. mGluR1 and mGluR5 are both coupled to inositol triphosphate (IP3)/calcium signal transduction with an identical agonist selectivity. Single-cell intracellular calcium ([Ca2+]i) recordings indicated that glutamate evokes a non-oscillatory and oscillatory [Ca2+]i response in mGluR1-expressing and mGluR5-expressing cells, respectively. This difference results from a single amino acid substitution, aspartate of mGluR1 or threonine of mGluR5, at the G protein-interacting carboxy-terminal domains. Protein kinase C phosphorylation of the threonine of mGluR5 is responsible for inducing [Ca2+]i oscillations in mGluR5-expressing cells and cultured glial cells. Thus, the two closely related mGluR subtypes mediate diverging intracellular signaling in glutamate transmission.

Animals↗

A case of leptomeningeal metastasis from lung adenocarcinoma diagnosed by reverse transcriptase-polymerase chain reaction for carcinoembryonic antigen.

A case of leptomeningeal metastasis from lung adenocarcinoma is reported. In this case, we evaluated the feasibility of reverse transcriptased polymerase chain reaction (RT-PCR) methods to detect cancer cells in cerebrospinal fluids (CSF). Messenger RNA of carcinoembryonic antigen (CEA) was clearly demonstrated in CSF by reverse RT-PCR methods. An immunohistochemical study also demonstrated that tumor cells were stained positive with anti-CEA antibody. This case suggests that RT-PCR for CEA was a sensitive and useful method to diagnose leptomeningeal metastasis from lung adenocarcinoma.

Adenocarcinoma↗

Immunization with the "immunogenic peptide" of TSH receptor induces oligoclonal antibodies with various biological activities.

Balb/c mice were immunized with a synthetic peptide (P354-14) corresponding to "the immunogenic peptide" of human thyrotropin receptor (hTSH-R). Through screening for binding to the peptide, we obtained several monoclonal antibodies with various biological activities: thyroid stimulation (SAb), inhibition of TSH stimulation (BAb) and no significant effect on cAMP production. One of the stimulatory clones was further studied. This clone enhanced cAMP production in Cos-7 cells transformed with the truncated TSH-R cDNA deleting the immunogenic peptide. These results indicated that the immunogenic peptide of the TSH-R induces oligoclonal anti-TSH-R antibodies, although the region is not essential for the functional epitope.

Animals↗

Severe heat stroke associated with high plasma levels of plasminogen activator inhibitor 1.

In a 38-year-old man, severe heat stroke caused disseminated intravascular coagulation (DIC) associated with significantly elevated plasma plasminogen activator inhibitor 1 levels. Investigation of the effects of hyperthermia on coagulation and fibrinolysis showed, in apparent conflict with previous reports, a time lag between the initial hypercoagulable and hyperfibrinolytic response (within 24 hr) and hypofibrinolysis shown by a disproportionate increase of PAI-1 (after 24 h), which possibly occurs in correspondence with the recovery of vascular endothelial integrity. The patient was discharged without sequelae although computed tomography (CT) scans indicated the likelihood of venous infarction or posterior inferior cerebellar artery area infarction secondary to DIC.

Adult↗