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Biomedical subjects

H Sekiguchi

Publications and source records attributed to H Sekiguchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

Aneurysmal dilatation of the pulmonary trunk with mild pulmonic stenosis.

We present the unusual case of a 72-year-old woman whose chest X-ray showed an abnormal left hilar shadow. A pulmonary angiogram revealed an aneurysm in the pulmonary artery with a diameter of 55 mm that extended from the main pulmonary trunk to its bifurcation. Mild pulmonic stenosis with a systolic pressure gradient of 18 mmHg across the pulmonic valve was recognized. Mild dilatation of the ascending aorta was also present. The pressure gradient across the pulmonic valve was lower than is typical for an aneurysmal dilatation, suggesting that this patient represented a case of idiopathic pulmonary artery dilatation. We suspected the presence of a congenital structural alteration common to the pulmonary artery and the ascending aorta.

Aged↗
PubMed1995

[Augmentation by succinylcholine of the neuromuscular blocking effect of vecuronium in children].

To evaluate the influence of succinylcholine (Scc) on the neuromuscular blocking effect of subsequently administered vecuronium in children, 30 patients aged 2-14 years scheduled for elective surgery were studied after obtaining the informed consent from the parents. Anesthesia was induced with inhalation of sevoflurane, nitrous oxide and oxygen. T1 of the adductor pollicis muscle to ulnar nerve stimulation elicited by train of four stimulation at 2 Hz was monitored continuously by an acceleration transducer. The patients were divided into two groups; group V (16 patients) received vecuronium (0.03 mg.kg-1) and group SV (14 patients) received vecuronium (0.03 mg.kg-1) after 100% recovery of twitch from neuromuscular blockade induced with Scc (1.0 mg.kg-1). Short onset of action and potentiation of maximal block were demonstrated in group SV. After vecuronium administration, a complete suppression of T1 was observed in 8 patients of group SV and only 1 patient of group V. The present study demonstrates that the neuromuscular blockade of vecuronium can be potentiated with the prior administration of Scc in pediatric patients.

Adolescent↗
PubMed1995

[Precipitation of pH-adjusted local anesthetics with sodium bicarbonate].

Sodium bicarbonate has been added to various local anesthetics for shortening the onset time. We often noticed the precipitate in the pH-adjusted local anesthetics several minutes after adding the bicarbonate. We confirmed that this drug interaction was caused by large changes in pH. We have analyzed the precipitates by mass spectrometry and infrared absorption spectrum and have revealed it as unionized base forms of local anesthetics. Since these forms tend to be insoluble, we must limit the amount of 7% sodium bicarbonate. This study proposes a guideline for adding 7% sodium bicarbonate to the various local anesthetics. The amount of 7% sodium bicarbonate which can be added to bupivacaine without precipitation is below 0.02 ml. In cases of mepivacaine and lidocaine, allowable amount of 7% sodium bicarbonate is 0.5 ml. It is not known whether this lower dose of 7% sodium bicarbonate compared with the recent reports is effective or not. Further clinical investigation may be necessary.

Anesthetics, Local↗
PubMed1994

Multicystic aneurysmal dilatation of bilateral coronary artery fistula.

Bilateral coronary artery fistula constitutes an uncommon subgroup of coronary artery fistulas that may have a distinct embryologic origin. Coronary artery fistulas usually show a tortuous arrangement upon coronary angiography, but aneurysmal dilatation is rare. We report here an extremely rare case of coronary artery fistula originating from both coronary arteries, which showed multicystic aneurysmal dilatation.

Aged↗
PubMed1994

Noninvasive evaluation of the influence of aortic wave reflection on left ventricular ejection during auxotonic contraction.

To develop a noninvasive method for evaluating the influence of aortic wave reflection on left ventricular ejection, the carotid pulse wave and the pulsed Doppler wave in the left ventricular outflow tract were evaluated in 35 patients. Agreement between the pulsed Doppler waveform and the aortic flow velocity contour (obtained invasively) was verified by Fourier analysis. The carotid augmentation index was used to determine the magnitude of the aortic pressure wave reflection. A Doppler index named "DR1/3" was defined as the ratio of deceleration at the first one-third in the deceleration phase to the peak flow velocity of the pulsed Doppler. This index was validated by close correlation with the carotid augmentation index (n = 48, r = 0.70, P < 0.01). Both nitrates and nifedipine induced a significant decrease in DR1/3 (indicating an increase in left ventricular ejection flow) in relation to a reduction of the reflected pressure wave. The new noninvasive index, DR1/3, is useful in evaluating the influence of aortic wave reflection as part of the left ventricular afterload and in assessing the benefit of treatment aimed at reducing wave reflection.

Aorta↗
PubMed1994

Effects of sevoflurane, isoflurane, enflurane, and halothane on left ventricular diastolic performance in dogs.

The effects of volatile anesthetics on active (ventricular relaxation) and passive (chamber stiffness) indices of diastolic function and on left ventricular filling rates in dogs were studied to determine how these agents affect left ventricular diastolic performance. Thirty-five mongrel dogs were randomly assigned to receive sevoflurane, isoflurane, enflurane, or halothane. Left ventricular pressure waveforms, phonocardiograms, and echocardiograms were recorded after administering the anesthetics at concentrations of 0% (control), 1%, 2%, and 3%. Ventricular relaxation was defined as the time constant of the decline in left ventricular pressure. Chamber stiffness was derived from the ventricular pressure-volume relationship during passive filling. Rapid filling rate, slow filling rate, and atrial filling rate were obtained from echocardiograms and phonocardiograms. No change in the time constant or in chamber stiffness was observed at any concentration of sevoflurane or isoflurane. However, the highest studied concentration of enflurane and halothane produced a significant increase in the time constant and in chamber stiffness. Rapid filling rate as well as atrial filling rate decreased significantly with the volatile anesthetics, especially with enflurane and halothane. Sevoflurane and isoflurane did not alter ventricular relaxation or chamber stiffness, but did affect diastolic function as manifested by their alteration of filling rates. In contrast, enflurane and halothane each prolonged ventricular relaxation and increased chamber stiffness. With the administration of the volatile anesthetics, the rapid filling rate decreased with the deterioration of diastolic function; in addition, atrial filling rates decreased and did not compensate for the reduction in early ventricular filling.

Anesthetics, Inhalation↗
PubMed1994

A new protocol and criteria for quantitative determination of sensitization potencies of chemicals by guinea pig maximization test.

This paper presents precise sensitization test data of 15 chemicals with a wide spectrum of sensitization potencies, and proposes a new protocol and criteria for quantitative evaluation of sensitization potencies of chemicals. The tests were performed according to the design of Magnusson and Kligman, changing the application concentrations for induction as well as for challenge phases. 3-dimensional relationships between mean response (or sensitization rate), induction and challenge concentrations were found in all chemicals tested. The following 2 values are proposed as a quantitative measure of sensitization potency: (a) the minimum induction concentration that induces a positive response; (b) the challenge concentration that induces a mean response approximately equal to 1.0 among the animals applied with the highest concentration for induction. Both values coincided with each other within the range of 1 order of magnitude in every compound except 2. The values varied by 5 orders or more of magnitude among the compounds, showing a wide variation of sensitization potencies among chemicals. A good correlation was found for every chemical between the value of sensitization potency thus obtained and the residual levels in causative products in human cases of allergic contact dermatitis. A new experimental protocol for obtaining values (a) and (b) is proposed.

Allergens↗
PubMed1994

Irreversible cardiomyopathy due to thyrotoxicosis.

We report 4 adult patients with thyrotoxicosis accompanied by irreversible low-output heart failure. Each patient showed elevated plasma levels of thyroid hormone and prolonged low-output heart failure even after thyroid function returned to normal. Specimens of the right ventricular myocardium stained with anti-beta myosin heavy-chain MAb showed a normal staining pattern with a predominance of the beta-form. Our observations suggest that thyrotoxicosis may be one possible cause of irreversible cardiomyopathy.

Aged↗
PubMed1994

Endothelin production in pulmonary circulation of patients with mitral stenosis.

BACKGROUND: Although plasma endothelin concentrations are elevated in patients with pulmonary hypertension, the precise sites of endothelin production have not been defined. We investigated the endothelin production in the pulmonary circulation of patients with mitral stenosis and its effects on pulmonary vascular tone. METHODS AND RESULTS: We measured plasma concentrations of endothelin-1, angiotensin II, and thrombomodulin in blood samples obtained from the right and left atria of 10 consecutive patients with rheumatic mitral stenosis (mean age, 55 years; range, 39 to 68) who were undergoing percutaneous mitral valvuloplasty. Plasma levels of endothelin-1 were significantly higher in the left atrium than in the right atrium (3.25 +/- 0.45 versus 2.53 +/- 0.36 pg/mL, mean +/- SE, P < .001). The increased plasma endothelin-1 level in the left atrium, which reflected endothelin-1 production in the pulmonary circulation, was correlated with mean pulmonary artery pressure (r = .65, P = .04), mean pulmonary arterial wedge pressure (r = .67, P = .03), total pulmonary resistance (r = .68, P = .03), and 1/mitral valve area (r = .85, P = .002) but not with pulmonary vascular resistance (r = .04, P = .91). There were no significant differences in plasma levels of angiotensin II and thrombomodulin between the right and left atria (angiotensin II, 16.40 +/- 3.08 versus 15.50 +/- 4.85 pg/mL; thrombomodulin, 2.96 +/- 0.34 versus 2.85 +/- 0.37 ng/mL). CONCLUSIONS: Endothelin-1 production is increased in the pulmonary circulation of patients with mitral stenosis in response to increased pulmonary artery pressure but is not directly related to increased pulmonary vascular tone in this disorder.

Angiotensin II↗
PubMed1994

Polysplenia accompanied by major cardiovascular anomalies with prolonged survival.

A 52-year-old female with polysplenia accompanied by major cardiovascular anomalies (a ventricular septal defect, atrial septal defect, persistent left superior vena cava, absent inferior vena cava with a hemiazygos connection and visceral heterotaxia) is reported. She underwent successful surgical treatment and showed prolonged survival.

Abnormalities, Multiple↗
PubMed1994

The clinical course of acquired aplastic anemia in childhood; a retrospective study.

We reviewed the clinical courses of 38 children with acquired aplastic anemia (AA). The patients were classified according to the severity criteria by the Japanese Ministry of Health and Welfare (JMHW) Study Group (22 severe, 15 moderate, 1 mild). Early death was observed only in severe cases. Eight of the non-severe cases progressed to severe in 0.5-125 months, and the long-term survival rate of non-severe AA did not differ from that of severe AA. The frequency of lymphocytes in the bone marrow was significantly higher, and the peripheral blood neutrophil count was lower in patients who died within a year, and these patients should be treated as very severe. These findings suggest that the JMHW Study Group criteria are useful for identifying AA patients with a poor prognosis, but even non-severe cases should be repeatedly evaluated. Sixteen of the 33 patients treated with corticosteroids and/or anabolic steroids (AS) showed hematological recovery. Bolus methylprednisolone (mPSL) therapy was effective in one of the 8 patients. Allogenic marrow transplant (BMT) was performed on 3 patients. One died from sepsis and engraftment was not achieved in the other two. Trilineage recovery was obtained in 3 of 6 patients treated with rhG-CSF and rhEPO with or without AS, and hemopoiesis has been maintained 6-12 months after discontinuation in 2 cases. In the other 3 patients, the neutrophil count showed transient increase. Therefore, the treatment for severe AA patients, who have no sibling donor for BMT, should be started with the combination therapy including these cytokines.

Adolescent↗
PubMed1994

[Anesthetic management of a patient with mild hypothyroidism].

A patient with mild hypothyroidism underwent a repair of abdominal aortic aneurysm. Although the serum TSH level of this patient was very high and T4, free T4 levels were low, T3 level remained within normal ranges. Inhalation anesthesia with continuous epidural block was selected and there was no complication such as hypotension or hypothermia during perioperative period. Recently, several reports demonstrate that the preoperative supplemental therapy of the thyroid hormone should not be necessary in the case of mild hypothyroidism. Moreover, the biological potency of T3 is higher than that of T4. Thus, in patients whose T3 level is kept within normal ranges even if serum T4 level is low and serum TSH level is high, we may say that they are in euthyroid state. We think these patients can be anesthetized safely.

Anesthesia, Epidural↗
PubMed1994

[Vaporizer malfunction--a cause of high concentration halothane vapor delivery].

Excessively high concentration of halothane vapor was delivered to the inspiratory gas mixture due to the vaporizer malfunction (Fluotec 4). After disassembling the vaporizer, corrosion was observed on the internal components. This was considered as the reason for the high halothane output. Proper regular check up, use of appropriate monitoring devices, and a preuse equipment checklist may help improve the quality of patient care and decrease the morbidity and mortality associated with anesthesia equipment. Anesthesia machines should receive regular check up at least once a year and anesthesia providers should routinely use an equipment checklist. It is also important to realize that anesthesiologist's senses of sight, hearing, touch, and smell are exceedingly reliable monitors for decreasing the incidence of anesthesia mishaps.

Anesthesia, Inhalation↗
PubMed1993

[Dermatological evaluation of a flame retardant, hexabromocyclododecane (HBCD) on guinea pig by using the primary irritation, sensitization, phototoxicity and photosensitization of skin].

As one of the projects in the safety evaluation of chemical constituents in common house-hold products, effects of hexabromocyclododecane (HBCD) were evaluated by primary skin irritation, skin sensitization, phototoxicity and photosensitization using guinea pigs. Primary skin irritation was not observed in HBCD emulsified in distilled water by the Draize test method. Skin sensitization test was carried out according to the maximization test method of Magnusson and Kligman. For this test, HBCD was dissolved in olive oil to give 5, 0.5 and 0.05%. When induction of sensitization occurred, challenged doses of 0.005, 0.05, 0.5 and 5% of HBCD (dissolved in acetone) were applied to its respective sensitized groups. The results showed that the induction dose of greater than 0.5% and the challenge dose of greater than 0.05% elicited a positive response. The increase in the concentration of induction and challenge doses did not further increase the percentage of positive response or the intensity of skin response. Phototoxicity test was carried out with 0, 0.5 and 5% of HBCD dissolved in acetone. Phototoxicity was not observed at all HBCD concentration tested. Photosensitization test was performed according to the Sato's adjuvant-strip method. The skin sensitization and challenge reaction doses were 5 and 0.5% and 0 and 0.5% HBCD (dissolved in acetone), respectively, and no positive reaction was observed. It is clear from the foregoing results that HBCD is a mild skin allergen.

Animals↗
PubMed1993

Pharmacological profiles of the new histamine H2-receptor antagonist N-ethyl-N'-[3-[3-(piperidinomethyl)phenoxy] propyl] urea.

The histamine H2-receptor antagonistic activity and antisecretory effects of KU-1257 (N-ethyl-N'-[3-[3-(piperidinomethyl) phenoxy]propyl]urea, CAS 120958-90-9) were studied. The Ki values of KU-1257, roxatidine acetate, famotidine and cimetidine for the inhibition of [3H]-tiotidine binding to guinea-pig cerebral cortex were 0.040, 0.13, 0.016 and 0.40 mumol/l, respectively. The KB values of KU-1257, roxatidine acetate, famotidine and cimetidine for the antagonism against histamine-induced positive chronotropic response of isolated guinea-pig right atrium were 0.041, 0.14, 0.031 and 0.51 mumol/l, respectively. In pylorus-ligated rats, KU-1257, roxatidine acetate and famotidine inhibited gastric acid secretion with respective intraduodenal ID50 values of 12.3, 18.5 and 0.45 mg/kg. In dogs with Heidenhain pouch, the ID50 values of KU-1257 for the inhibition of acid output stimulated by histamine, tetragastrin and meat meal were 0.08, 0.39 and 0.15 mg/kg p.o., respectively. KU-1257 was 2-3 times more potent than roxatidine acetate regardless of secretagogues and twice less than famotidine in meat meal stimulation. These results indicate that KU-1257 is a potent and competitive histamine H2-receptor antagonist.

Animals↗