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Biomedical subjects

S Sawaki

Publications and source records attributed to S Sawaki.

At least 19 recordsLinked to original sources
PubMed2005

[Primary cardiac angiosarcoma in the left atrium with adrenal metastasis; report of a case].

We encountered a 61-year-old woman with primary cardiac angiosarcoma in the left atrium. On echocardiography, the tumor extended into the atrial septum and mitral valve, and mitral valve stenosis and regurgitation were significant. We resected the tumor protruding into left atrium, and affecting mitral valve. The surgical procedure was not radical, but on postoperative echocardiography, function of the mitral valve was improved. Three months later, elevation of her right diaphragma was observed on chest X-ray and a giant adrenal tumor was detected by magnetic resonance imaging. Tumor biopsy indicated that this tumor was adrenal metastasis from cardiac angiosarcoma. In addition, echocardiography showed the recurrence of angiosarcoma in the left atrium and the presence of mitral stenosis and regurgitation. She died of heart failure 185 days postoperatively.

Adrenal Gland Neoplasms↗
PubMed2005

[Repair of tetralogy of Fallot with obstruction of right pulmonary artery; report of a case].

Patients with tetralogy of Fallot showing unilateral obstruction of a pulmonary artery, especially the right pulmonary artery, are a high-risk group for pulmonary hypertension after repair. This case of tetralogy of Fallot with the obstruction of the right pulmonary artery received a Blalock-Taussig shunt at 7 months old, and the occluded right pulmonary artery caused empyema after surgery. At 2 years old, a cardiac catheter study showed a pulmonary artery index of 193.6 mm2/m2, so we undertook intracardiac repair. After the repair, she showed a relativery favorable clinical course. Systolic pulmonary artery pressure and right ventricular pressure were about 30 and 50 mmHg, respectively. We considered that tetralogy of Fallot with obstruction of right pulmonary artery could be repaired, as long as the pulmonary artery index was within the limits of indication and the left ventricle was well-developed.

Arterial Occlusive Diseases↗
PubMed2000

Insertion of bacteriophage phiFSW into the chromosome of Lactobacillus casei strain Shirota (S-1): characterization of the attachment sites and the integrase gene.

The integrase gene (int) on the genome of φFSW, which is a temperate bacteriophage of Lactobacillus casei strain Shirota (formerly denoted as S-1), and the four attachment sites on the genomes of the phage and its host were characterized by sequencing. The φFSW integrase was found to belong to the integrase family of site-specific tyrosine recombinase. The attachment sites shared a 40bp common core within which an integrative site-specific recombination occurs. The common core was flanked on one side by an additional segment of high sequence similarity. An integration plasmid, consisting of int, the phage attachment site (attP), and a selectable marker, inserted stably into the bacterial attachment site (attB) within the common core, as did the complete prophage genome at a frequency of more than 10(3)/microg of plasmid DNA. This plasmid was used as a test system for a preliminary mutational analysis of int and attP. The attB common core was located within and near the end of an open reading frame that appears to encode a homolog to glucose 6-phosphate isomerase, an enzyme of the glycolytic pathway. It is unlikely that the prophage integration inactivates this protein, since a change of only the C-terminal amino acid is predicted because of the sequence similarity between attP and attB.

Amino Acid Sequence↗
PubMed1998

Right ventricular responses to vagus stimulation of fibers to discrete cardiac regions in dog hearts.

To investigate the role on the right ventricular function of the parasympathetic nerves in discrete cardiac regions, we studied the effects of stimulation of the intracardiac parasympathetic nerves to the atrioventricular (AV) nodal area (AVPS) or sinoatrial (SA) nodal area (SAPS), and stimulation of the cervical vagus nerves (CVS) on the right atrial and ventricular function in the autonomically decentralized heart of the anesthetized dog. AVPS prolonged AV conduction time (AVCT) and decreased the ventricular rate without changes in atrial rate, right atrial 'a' wave pressure (RAP), its first derivative (RAd P/dt), right ventricular pressure (RVP) and its first derivative (RVd P/dt) in the spontaneously beating heart. On the other hand, AVPS prolonged the AVCT in the atrium paced electrically and further decreased the ventricular rate with decreases in ventricular pressure responses but not atrial responses. SAPS decreased atrial and ventricular rates without AVCT changes and attenuated the right atrial and ventricular pressure responses. In the atrial paced heart, SAPS decreased the ventricular responses less than those responses in the spontaneously beating heart with similar decreases in the atrial pressure responses, but it changed neither the AVCT nor ventricular rate. On the other hand, CVS decreased the atrial and ventricular rate or pressure responses, and increased the AVCT. CVS in the paced heart also decreased the atrial and ventricular pressure responses with the prolongation of AVCT. The cardiac responses to parasympathetic stimulations were abolished by atropine. These results suggest that AVPS decreases ventricular rate without direct right ventricular pressure effects but the negative chronotropic effects of AVPS and SAPS decrease the ventricular pressure responses rate-dependently in the dog heart.

Animals↗
PubMed1995

Zatebradine attenuates cyclic AMP-related positive chronotropic but not inotropic responses in isolated, perfused right atria of the dog.

1. Inhibition of I(f) or ICa by zatebradine has been reported in mammalian SA nodal cells. We thus investigated whether zatebradine differentially attenuates the positive chronotropic and inotropic responses to norepinephrine, isoproterenol, NKH 477 (an adenylyl cyclase activator), 3-isobutyl-1-methylxanthine (IBMX) and Bay k 8644 (a calcium channel agonist) in the isolated, blood-perfused dog atrium. 2. When zatebradine (0.03-1 mumol) decreased sinus rate from 104 +/- 4.5 to 73 +/- 4.9 beats/min dose-dependently, it selectively attenuated the positive chronotropic but not inotropic responses to norepinephrine in a dose-related manner. Zatebradine decreased the norepinephrine-induced tachycardia (by approximately 80% from the control) more effectively than the spontaneous sinus rate (by approximately 30% from the control). 3. Zatebradine similarly attenuated the positive chronotropic but not inotropic responses to isoproterenol, NKH 477 and IBMX. Fifty per cent inhibition doses of zatebradine (0.10-0.18 mumol) for the chronotropic responses to each substance were not significantly different. 4. On the other hand, zatebradine attenuated neither positive chronotropic nor inotropic responses to Bay k 8644. 5. We therefore suggest that zatebradine selectively attenuates the positive chronotropic but not inotropic responses to cyclic AMP-related substances due to inhibition of I(f) but not ICa in the dog heart.

1-Methyl-3-isobutylxanthine↗
PubMed1995

[A study of ceftriaxone concentration in serum and tissue of patients with chronic sinusitis].

After an intravenous drip infusion of 1 g or 2 g of ceftriaxone (CTRX), its concentrations in serum and tissue were determined using the bioassay for 18 surgical patients with chronic paranasal sinusitis. 1. The serum levels observed at 75-105, 135-165, 195-225 minutes after an intravenous drip infusion of 1 g, averaged 98 +/- 38, 92 +/- 13 and 73 +/- 13 micrograms/ml, respectively. 2. The tissue levels at 75-105, 135-165, 195-225 minutes after an intravenous drip infusion of 1 g, averaged 27 +/- 13, 27 +/- 7 and 25 +/- 9 micrograms/g. 3. CTRX appears to be a useful drug for the treatment of chronic paranasal sinusitis.

Adult↗
PubMed1995

Are negative chronotropic and inotropic responses to adenosine differentiated at the receptor or postreceptor levels in isolated dog hearts?

Inhibition by zatebradine, a specific bradycardic agent, of the negative inotropic but not chronotropic responses to adenosine has been briefly reported in the isolated, perfused dog heart. We therefore investigated whether subtypes of adenosine receptors or postreceptor transduction mechanisms differentiated the negative chronotropic and inotropic responses to adenosine in the isolated, blood-perfused atrial and ventricular preparations of the dog. Adenosine (1-3000 nmol), adenosine A1 receptor agonists, 2-chloroadenosine (CAD, 0.1-300 nmol) and N6-cyclohexyladenosine (CHA, 1-300 nmol) and a nonselective adenosine receptor agonist, 5'-N-ethyl-carboxamidoadenosine (NECA, 0.1-100 nmol), induced the negative chronotropic and inotropic responses. The potency order was NECA > CAD > adenosine > or = CHA. An adenosine A1 receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10-300 nmol), dose-dependently inhibited the negative chronotropic and inotropic responses to adenosine, CAD and NECA in the isolated, perfused right atrium. DPCPX also blocked the negative inotropic responses to adenosine, CAD and NECA in the isolated left ventricle. However, an adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX, 300 nmol), did not affect the negative cardiac responses to adenosine and NECA. Although the negative inotropic but not chronotropic responses to CAD and adenosine were dose-dependently inhibited by zatebradine, K+ channel inhibitors 4-aminopyridine and E-4031 did not modify the cardiac responses to adenosine and CAD. These results suggest that the negative cardiac responses to adenosine are mediated by adenosine A1 receptors and the negative chronotropic and inotropic responses to adenosine are differentiated at the postreceptor transduction level(s) in the dog heart.

2-Chloroadenosine↗
PubMed1994

Parasympathetic control of right atrial pressure in anesthetized dogs.

We investigated whether the intracardiac parasympathetic ganglia for sinoatrial (SA) nodal pacemaker cells control the right atrial contractility selectively and totally in the autonomically decentralized heart of the open-chest anesthetized dog. Stimulation of the intracardiac parasympathetic nerves to the SA nodal area (SAP Stim) decreased the right atrial pressure (a wave pressure) and its first pressure derivative (dP/dt) as well as the atrial rate but did not change the atrioventricular (AV) conduction time. Stimulation of right and left cervical vagosympathetic complexes (CV Stim) decreased the a wave pressure, dP/dt, and atrial rate and prolonged the AV conduction time. When SAP and CV Stim decreased the atrial rate similarly, the decreases in a wave pressure and dP/dt in response to SAP Stim were less than those to CV Stim in unpaced and paced hearts. When treatment with hexamethonium bromide or tetrodotoxin into the SAP Stim locus abolished the decreases in atrial rate evoked by SAP and CV Stim, each treatment abolished the decrease in a wave pressure response to SAP Stim but only slightly attenuated the pressure response to CV Stim. These results demonstrate that right atrial pressure is modified by efferent parasympathetic neurons, which are located in a region that differs from that of efferent parasympathetic neurons controlling heart rate.

Animals↗
PubMed1993

Selective inhibition by E4080, a novel bradycardic agent, of positive chronotropic responses to norepinephrine in isolated dog hearts.

E4080, a novel bradycardic agent acts on various ionic currents including the hyperpolarization-activated inward current (I(f)), L-type Ca2+ current (ICa) and ATP-sensitive K+ (K+ATP) current in mammalian heart and vascular tissues. We thus investigated the chronotropic and inotropic effects of E4080 and its interaction with the positive cardiac responses to norepinephrine, 3-isobutyl-1-methyl-xanthine (IBMX) and Bay k 8644 in the isolated, blood-perfused dog right atria and left ventricles. E4080 (0.01-1 mumol) decreased the sinus rate and atrial and ventricular contractile forces in a dose-related manner. Glibenclamide (3 mumol) partly blocked the decrease in atrial force but not the decreases in sinus rate and ventricular force induced by E4080. Atropine (10 nmol) did not affect the negative cardiac responses to E4080. E4080 (0.01-1 mumol) inhibited the positive chronotropic responses to norepinephrine and IBMX dose dependently, but did not inhibit the positive inotropic ones in isolated atria. E4080 affected neither positive chronotropic nor inotropic responses to Bay k 8644. These results suggest that (1) the activation of K+ATP channels by E4080 is partly related to the decrease in atrial force but not the decreases in sinus rate and ventricular force, and (2) the selective inhibition of E4080 of the cyclic AMP-dependent positive chronotropic responses but not inotropic ones is probably due to the inhibition of I(f) rather than other properties, e.g., activation of K+ATP channels and inhibition of ICa in the dog heart.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Positive chronotropic and inotropic responses to BRL 37344, a beta 3-adrenoceptor agonist in isolated, blood-perfused dog atria.

We investigated the chronotropic and inotropic responses to BRL 37344 (a beta 3-adrenoceptor agonist) and isoproterenol in isolated, blood-perfused dog atria. BRL 37344 (0.1-30 nmol) or isoproterenol (0.001-0.3 nmol) increased the sinus rate and contractile force dose dependently. BRL 37344 was 290 times less potent than isoproterenol to increase sinus rate and 140 times less potent to increase atrial force. Both propranolol and bisoprolol similarly inhibited the positive chronotropic and inotropic responses to BRL 37344 and isoproterenol dose dependently. ICI 118,551 (0.1 and 1 nmol) did not significantly affect the positive cardiac responses to BRL 37344 or isoproterenol. Neither imipramine nor tetrodotoxin significantly affected the positive cardiac responses to BRL 37344. These results suggest that the positive chronotropic and inotropic responses to BRL 37344 are mediated mainly by beta 1-adrenoceptors in the dog heart. It is unlikely that beta 3-adrenoceptors, as previously reported in adipose tissue or gastrointestinal smooth muscle, mediate chronotropic and inotropic responses in the normal dog heart.

Adrenergic beta-Agonists↗
PubMed1993

A trial of individual dose intensity and relative performance factors in tegafur maintenance chemotherapy for head and neck cancer.

Tegafur (Sunfural-S), as masked compound of a 5-fluorouracil derivative, was administered orally as a maintenance chemotherapeutic agent at a dose of 600 mg/day in 98 cases of head and neck epithelial cancer. The effectiveness of the drug was evaluated by a statistical method involving two formulae: individual dose intensity (IDI) and relative performance (RP). When comparing patients rated above a reference IDI value of 1.0 with those rated below 1.0, it was not possible to predict patient survival or tumor-free rates. In contrast, the value of the RP did show such a correlation. These findings support the effectiveness of Tegafur as a maintenance chemotherapeutic treatment for head and neck cancer patients.

Aged↗
PubMed1993

Chemotherapy for recurrent adeno- and adenoidcystic carcinomas in the head and neck.

We have investigated the effectiveness of chemotherapy for patients with recurrent adeno- and adenoidcystic carcinomas in the head and neck. Fourteen cases received a monthly combination chemotherapy regimen of cyclophosphamide, pirarubicin and cisplatin (CAP therapy). A response rate of 36% (5/14) was achieved. There was one complete response and four partial responses. The median duration of response was 37 months in the complete response case and 16 months (range, 6 to 20) in the partial response cases. The toxicity of this chemotherapy was acceptable. The result demonstrates that CAP therapy is an effective regimen for adeno- and adenoidcystic carcinomas. It may also be available as induction or adjuvant chemotherapy for patients with advanced tumors of these cancers.

Adenocarcinoma↗
PubMed1993

Suppressed cellular immunity in patients with nasopharyngeal carcinoma.

The subsets and functions of lymphocytes were investigated in patients with nasopharyngeal carcinoma (NPC). The patients were divided into two groups comprising tumor-bearing patients and those in remission. There was no difference in the proportion of T cells among tumor-bearing, remission and healthy control groups. The percentages of inducer/helper T cells and natural killer cells were smaller in the tumor-bearing group than in the control group whereas the percentage of suppressor T cells was greater in the tumor-bearing group. Phytohemagglutinin-stimulated blastogenesis was markedly suppressed in the tumor-bearing group. The responsiveness to interleukin-2 of blastogenesis and of natural killer and lymphokine-activated killer activities was lowered in the tumor-bearing group. These parameters in the remission group were intermediate between those of the tumor-bearing and control groups. These results suggest that cellular immunity is suppressed in patients with NPC and that the suppressed condition still remains even in remission. Immunotherapy is considered to be indispensable for the proper treatment of NPC.

Adult↗
PubMed1993

Clinical application of recombinant human erythropoietin for treatments in patients with head and neck cancer.

The therapeutic effects of intravenous recombinant human erythropoietin (r-hEPO) administration on anemia induced by radiation therapy (3 cases), chemotherapy (18 cases) and combined therapies (5 cases) in patients with head and neck malignancies were examined. The effectiveness was evaluated by the changes in the hemoglobin concentration examined before and after the r-hEPO administration. The r-hEPO administration combined with anticancer therapies improved anemia induced by all three treatments. The therapeutic effectiveness of r-hEPO injection was also noted on anemia induced by all of four different chemotherapeutic regimens that have been ordinarily used for head and neck malignancies. Furthermore, the efficacy of the different dose schedules, 3000 IU (12 cases) or 6000 IU (14 cases), three times a week, was compared. Both of the r-hEPO dose schedules were effective for anemia, but the efficacy of 6000 IU was superior to that of 3000 IU. No significant changes were observed in the number of white blood cells and platelets and the results of biochemical examinations after the r-hEPO injection. There were no objective side-effects related to the r-hEPO administration. These results suggest that anemia induced by chemotherapy and/or radiotherapy could be prevented by r-hEPO administration. The addition of r-hEPO to anticancer therapies would make it possible to pursue the planned therapeutic schedules, prevent the decrease of immunity after allogeneic blood transfusion and bring about an-improvement in the prognosis of patients with malignancies.

Adult↗
PubMed1993

Extramedullary plasmacytoma of the larynx.

A case of IgD myeloma in a 54-year-old male with a long-standing history of extramedullary plasmacytoma involving the larynx is reported. The patient was treated with radiation therapy and laryngectomy. Twelve years later, he complained of nasal bleeding. On examination he was found to have large masses in the left nasal cavity and in the left supraclavicular region. Histological examination of both lesions showed plasmacytoma. Serum immunoglobulin studies revealed an IgD monoclonal spike of the lambda type. Bence-Jones protein was present. Using the immunoperoxidase staining technique, cytoplasmic monoclonal IgD was detected.

Bone Neoplasms↗
PubMed1993

Tumours metastasizing to the head and neck--a report of seven cases.

Metastatic tumours involving the head and neck region are rare. Over the past 18 years, seven such cases were treated at our clinic. Of those, four were in one of the paranasal sinuses, three had arisen from a primary hepatocellular carcinoma and one from an osteogenic fibrosarcoma of the leg. In the remaining three cases, metastases to the larynx, the tonsil, and the parotid gland arose from a primary renal cell carcinoma, a thyroid carcinoma, and a breast carcinoma, respectively. In metastatic tumours, the primary site can often be identified by the histopathological features. Accordingly, when malignant head and neck tumours are suspected of being metastatic in character, it is important to search carefully for the primary site.

Adult↗
PubMed1993

Inhibition by omega-conotoxin GVIA of the chronotropic responses to sympathetic and parasympathetic nerve stimulation in the isolated, blood-perfused atrium of the dog.

1. We investigated the effects of omega-conotoxin GVIA (omega-CgTX), a blocker of N-type voltage-operated calcium channels, on the chronotropic response to stimulation of the intracardiac sympathetic and parasympathetic nerves in the isolated, blood-perfused right atrium of the dog. 2. omega-CgTX (0.3-3 nmol) itself did not affect the sinus rate significantly, but it inhibited the negative followed by positive chronotropic response to simultaneous stimulation of sympathetic and parasympathetic nerves in a dose-dependent manner. 3. omega-CgTX at higher doses (1-3 nmol) inhibited the positive response to sympathetic stimulation more strongly than the negative response to parasympathetic stimulation. omega-CgTX (3 nmol) abolished the positive chronotropic response to sympathetic nerve stimulation in the atrium treated with atropine, but did not abolish the negative response to selective parasympathetic stimulation. Neither the chronotropic response to noradrenaline nor the response to acetylcholine was affected by omega-CgTX. 4. These results indicate that omega-CgTX inhibits not only the response to sympathetic stimulation but also the response to parasympathetic stimulation in the dog heart and it inhibits the positive chronotropic response to sympathetic stimulation more strongly than the negative chronotropic response to parasympathetic stimulation.

Acetylcholine↗