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Biomedical subjects

N Hirata

Publications and source records attributed to N Hirata.

At least 109 records · Page 6Linked to original sources
PubMed1993

[A study on markers of bone metabolism in patients with non hypercalciuric calcium stone--measurement of gamma-carboxyglutamic acid and hydroxyproline].

Thirty-one patients (26 male and 5 female patients) of non-hypercalciuric Ca stone formers were studied concerning their bone metabolism. We measured plasma free gamma-carboxyglutamic acid, plasma hydroxyproline, urinary free gamma-carboxyglutamic acid and urinary hydroxyproline as markers of bone metabolism. Plasma free gamma-carboxyglutamic acid level showed significantly higher in stone formers than normal controls (1.01 +/- 0.37 nmol/ml vs 0.39 +/- 0.13 nmol/ml). But no significant difference were observed in plasma hydroxyproline level (1.99 +/- 0.73 micrograms/ml vs 2.27 +/- 0.92 micrograms/ml), urinary free gamma-carboxyglutamic acid (52.0 +/- 17.6 nmol/mg.Cr vs 45.7 +/- 9.8 nmol/mg.Cr), and urinary hydroxyproline (3.87 +/- 2.02 micrograms/mg.Cr vs 3.33 +/- 1.63 micrograms/mg.Cr). In conclusion, these results suggest that abnormality of bone metabolism may be not a primary event in causing stone formation in these patients.

1-Carboxyglutamic Acid↗
PubMed1993

[Treatment for cardiac rupture following acute myocardial infarction].

We experienced thirty-three patients with cardiac free wall rupture following acute myocardial infarction (AMI). Twelve patients received reperfusion therapy. Surgical closure of cardiac rupture was performed in twelve patients under cardiopulmonary bypass (CPB). Two of these patients were placed on percutaneous cardiopulmonary support system (PCPS) immediately after the onset of blow out rupture. Cardiac rupture occurred in 19 patients within 3 days from the onset of AMI (early rupture) and in 14 patients 4 days after the onset (delayed rupture). All five patients with successful reperfusion were in the early rupture group, while there were no patients with successful reperfusion in the delayed rupture group. In 12 surgical patients, 7 patients had blow out rupture and 5 patients had oozing rupture. In 7 patients with blow out rupture, four patients could not be disconnected from CPB and 2 patients had cerebral death. One patient received PCPS support showed no mental disturbance after surgery, but he died of renal failure 6 days after surgery. Three out of 5 patients with oozing rupture survived. The interval from the onset of hypotension to establishment of cardiopulmonary support was 5 minutes and 60 minutes in two patients using PCPS. However it averaged 94 minutes in 5 patients using usual CPB. It is suggested that early reperfusion therapy may prevent delayed cardiac rupture following AMI, and surgical therapy using PCPS may be useful for the treatment of cardiac blow out rupture.

Adult↗
PubMed1993

[Antireflux operation for vesicoureteral reflux in spina bifida patients].

A series of 32 patients with spina bifida, representing 50 renal units with vesicoureteral reflux (VUR), was treated with antireflux operation. All but one patient underwent ureteral reimplantation with Cohen's technique. Another patient was treated with bilateral Politano-Leadbetter's technique. The overall success rates were 92.0% by renal unit and 87.5% by case, with a mean follow-up period of 42.5 months. These results were comparable to those in the recent literature. Failure included recurrence of VUR in 3 patients. Another patient who had undergone unilateral reimplantation developed new occurrence of reflux in the contralateral ureter. Possible masking of contralateral VUR should be taken into consideration in patients with unilateral high grade VUR. We also emphasize the importance of continuing clean intermittent catheterization in a proper manner to be free of VUR postoperatively.

Adolescent↗
PubMed1993

[Unresolved issues concerning the operative indication of augmentation cystoplasty in spina bifida patients: a report of two cases].

Augmentation cystoplasty is evolving into a common method of surgical treatment for a low capacity and/or low compliance neurogenic bladder. Although an increasing number of successful results have been recently reported, the operative indication of augmentation cystoplasty is yet to be established. Herein, we report two cases of neurogenic bladder due to spina bifida which required abandonment of augmentation cystoplasty. The first case was in a 23-year-old female with a severely deformed bladder and right vesicoureteral reflux (VUR). She refused to undergo ileocystoplasty because we could not assure her of postoperative conception which she eagerly anticipated. The second case was in a 19-year-old male with a severely deformed bladder and right VUR. He experienced recurrent episodes of ventriculoperitoneal shunt (V-P shunt) difficulty which required exchanging the shunt tube each time, and each exchange proved to be very difficult or nearly impossible. Based on lengthy neurosurgical consultation, we came to the conclusion that ileocystoplasty was not a preferable treatment of choice for the correction of his disease due to the possibility of V-P shunt infection, which could be fatal. Alternatively, both cases were treated with Cohen's ureteral reimplantation, which resulted in the recurrence of VUR. These cases presented still unresolved issues concerning the operative indication of augmentation cystoplasty in spina bifida patients.

Adult↗
PubMed1992

Studies on the synthesis of sesquiterpene lactones, 14. Syntheses of (-)-arbusclin D and (+)-4-EPI-arbusclin D: the stereochemical assignment of arbusclin D.

Efficient syntheses of (-)-arbusclin D and (+)-4-epi-arbusclin D are reported. By these syntheses the C-4 stereochemistry of arbusclin D and the absolute configuration of (-)-arbusclin D have been determined to be a s shown in structure 1. The biological activities, such as cytotoxic activity toward P-388 lymphocytic leukemia, plant growth regulating activity, and antimicrobial activity of compounds 1, 3, 7, 9, 12, and 14 were also studied.

Animals↗
PubMed1992

Salmonella colitis: assessment with double-contrast barium enema examination in seven patients.

To completely rule out the possibility of ulcerative colitis, Crohn disease, and other diseases, the authors analyzed the radiographic findings at double-contrast barium enema examination performed in seven patients with colitis caused by Salmonella organisms. In all patients, bacteriologic confirmation of nontyphoid Salmonella infection and radiographs of the upper gastrointestinal tract were obtained. Total colonoscopy was performed in five patients and sigmoidoscopy in one patient. In all patients, the radiographic findings were retrospectively analyzed. The descending colon and sigmoid colon were affected in six patients, whereas the rectum was affected in none. The findings included fine mucosal granularity (seven patients), loss of haustration (six patients), many fine ulcerations (five patients), and multiple ulcers (two patients). The radiographic features simulated those of ulcerative colitis, except for absence of rectal abnormality. It is concluded that double-contrast barium enema examination is useful for detection of fine mucosal changes.

Adolescent↗
PubMed1992

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis.

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.

Adult↗
PubMed1992

Assessment of regional and transmural myocardial perfusion by means of intraoperative myocardial contrast echocardiography during coronary artery bypass grafting.

By using intraoperative myocardial contrast echocardiography, we assessed regional myocardial perfusion and transmural blood flow distribution immediately after myocardial revascularization. A total of 62 revascularized myocardial areas were studied in 31 patients undergoing coronary artery bypass grafting. The revascularized areas were divided into three different areas: S area, supplied by significantly stenosed coronary arteries (43 areas); C area, supplied by coronary collateral situation associated with totally occluded coronary arteries (12 areas); MI area, preexisting transmural myocardial infarction (7 areas). Myocardial contrast echocardiography was obtained by direct injection of 2 ml of sonicated 5% human albumin into the saphenous vein grafts at rest and during atrial pacing. Each area was divided into two layers of endocardial and epicardial halves, and myocardial enhancement of peak intensity was measured for each half and endocardial/epicardial gray level ratio was calculated: (1) The peak intensity of myocardial enhancement in S area and C area was significantly higher than that in MI area at rest as well as during pacing after myocardial revascularization. There was no significant difference in the peak intensity between S area and C area both at rest and during pacing. In S area the peak intensity significantly increased during pacing (p < 0.01), whereas it did not change in C area and MI area. (2) S area demonstrated no significant change in endocardial/epicardial intensity ratio during pacing. In contrast, the ratio in C area significantly decreased during pacing. (3) In S area with preoperative percent increase of segmental wall thickening lower than 25%, there was a significant correlation (r = 0.84, p < 0.001) between the peak intensity of myocardial enhancement and the postoperative changes of percent increase of segmental wall thickening in the revascularized areas. Thus, immediately after myocardial revascularization, intraoperative myocardial contrast echocardiography could provide a quantitative assessment of regional myocardial perfusion as well as blood flow distribution in the areas with myocardial infarction and with coronary collateral situation and in the areas supplied by stenosed coronary arteries.

Cardiac Pacing, Artificial↗
PubMed1992

Global left ventricular performance and regional systolic function after suture annuloplasty for chronic mitral regurgitation.

BACKGROUND: In surgery for chronic mitral regurgitation, the mitral subvalvular apparatus, including annulus, may play an important role in preserving left ventricular (LV) performance. The suture annuloplasty for mitral regurgitation allows annular contraction of the mitral valve. The potential effects of suture annuloplasty on the postoperative LV performance have not been fully defined. METHODS AND RESULTS: Global and regional LV function in 12 patients with suture annuloplasty were compared with 12 patients with conventional mitral valve replacement (MVR). Cineangiography and echocardiography were obtained before and 10.8 months after surgery. End-diastolic volume index and end-systolic volume index decreased significantly in both groups after surgery (p < 0.01). Ejection fraction remained unchanged in the suture annuloplasty group, whereas it decreased significantly in the MVR group after surgery (p < 0.01). There was a significant inverse relation between ejection fraction and end-systolic wall stress in the two groups after surgery (suture annuloplasty group, r = -0.69, p = 0.01; MVR group, r = -0.60, p = 0.04). The intercept on the y axis was significantly (p < 0.005) higher in the suture annuloplasty group than in the MVR group. In the suture annuloplasty group, cross-sectional area ejection fraction at the mitral valve level and at the papillary muscle level by LV two-dimensional echocardiography remained unchanged after surgery. In the MVR group, they decreased significantly after surgery (p < 0.01). There was a significant correlation between the cross-sectional area ejection fraction and the global ejection fraction at both levels after surgery. Therefore, the improvement of the regional wall motion can be attributed to the improvement of the global LV performance after suture annuloplasty. CONCLUSIONS: These data suggest that suture annuloplasty can provide more desirable postoperative LV systolic performance than conventional MVR by preserving both the contraction of the mitral annulus and the mitral valvular-ventricular interaction.

Echocardiography↗
PubMed1992

[The effects of oxygen and vasodilators on pulmonary hemodynamics and blood gases in chronic lung disease].

The effects of oxygen inhalation, nitroglycerin (NTG) and prostaglandin E1 (PGE1) on pulmonary hemodynamics and blood gases were studied in 15 patients with chronic lung disease (CLD). Cardiac catheterization was performed with Swan-Ganz catheter, and pulmonary hemodynamics and cardiac output were measured. After baseline hemodynamics and blood gas measurements were made, 15 patients inhaled oxygen for 15 minutes and the same measurements were repeated. Twenty minutes later, oxygen inhalation was stopped. Then the 15 patients were divided into two groups; one group was administered sublingual NTG (7 patients) and the other was administered PGE1 by continuous intravenous infusion (8 patients). Pulmonary hemodynamics and blood gas measurements were then performed. Oxygen inhalation significantly reduced mean pulmonary artery pressure (from 22.2 +/- 8.8 to 20.0 +/- 6.4 mmHg; p < 0.01) and heart rate (from 78.1 +/- 12.0 to 75.5 +/- 12.5 beats/min; p < 0.05). With respect to oxygenation, oxygen inhalation significantly increased PaO2 (from 68.6 +/- 10.7 to 113.4 +/- 31.4 mmHg; p < 0.01), PvO2 (from 35.1 +/- 3.7 to 38.0 +/- 3.3 mmHg; p < 0.01). Therefore, oxygen inhalation was thought to be useful in patients with chronic lung disease with pulmonary hypertension. Sublingual administration of NTG significantly reduced mean pulmonary artery pressure (from 24.1 +/- 0.2 to 17.6 +/- 6.8 mmHg; p < 0.01), C.I. (from 2.9 +/- 0.2 to 2.3 +/- 0.2 ml/min/m; p < 0.01), O2-transport (from 589.1 +/- 168.4 to 457.0 +/- 105.8 ml/min; p < 0.01), and had a tendency to decrease PvO2 (from 34.3 +/- 3.0 to 32.1 +/- 1.8 mmHg; p < 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Emergency coronary artery bypass grafting in patients with severe pump failure complicating acute myocardial infarction].

Thirty patients with severe pump failure (Killip's degree III or more) complicating acute myocardial infarction (MI) underwent emergency coronary bypass grafting (CABG). Average age was 66 years old and CABG was performed 2.6 days after the onset of MI. The patients were divided into two groups according to the mechanisms that can bring about severe pump failure: 19 patients had large MI alone (G-I). The other 11 patients had severe ischemia occurring either at areas distant from the site of coronary occlusion or in the previous area at risk (G-II). To estimate the ventricular wall motion quantitatively, the left ventricular wall was divided into 17 segments. Each segment was graded on a four-point scale: akinesis, 3; severe hypokinesis, 2; hypokinesis, 1; normal 0. Wall motion score was estimated by summing the number of asynergic segments score. In G-I, Cardiac index (CI (l/min/m2)) increased from 2.03 +/- 0.91 to 2.68 +/- 0.73 and pulmonary wedge pressure (PCWP (mmHg)) decreased from 28 +/- 5 to 15 +/- 5, 72 hours after the surgery (p < 0.01). In G-II, CI increased from 2.17 +/- 0.78 to 3.17 +/- 1.01 and PCWP decreased from 29 +/- 6 to 13 +/- 5 after the surgery (p < 0.01). There was no difference in preoperative and postoperative hemodynamics between two groups. The wall motion score at the risk area did not change postoperatively (from 16 +/- 7 to 17 +/- 9 in G-I, from 15 +/- 8 to 11 +/- 5 in G-II).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Assessment of the size and distribution of the coronary artery selected for bypass grafting using myocardial contrast echocardiography during coronary artery bypass surgery].

We assessed the size and distribution of the native coronary artery selected for bypass grafting, using myocardial contrast echocardiography by injection of sonicated agents into a saphenous vein graft, during surgical revascularization. A total of 69 saphenous vein grafts (LAD, 16; D1, 10; OM, 13; PL, 13; RCA, 17) were performed in 36 patients with right dominant system at preoperative coronary angiogram. The size of the area of revascularized myocardium was quantified with the ratio of its circumference to a full circle depicted on the left ventricular short-axis view at the mid-papillary level. The extents of the revascularized area to LAD stenosing at the proximal portion was 28 +/- 6% and stenosing at the intermediate portion was 23 +/- 6%. D1, 10 +/- 2%; OM, 17 +/- 3%; PL, 22 +/- 6%, RCA, 17 +/- 5%. The extent of the areas perfused by the totally occluded coronary arteries with collateral vessels was similar to those perfused by the partially occluded coronary arteries. In conclusion, myocardial contrast echocardiography enabled the intraoperative assessment of the geometry of regional myocardial perfusion, and was very useful for the intraoperative evaluation of the effectiveness of the indicated surgical procedure.

Arteries↗
PubMed1992

[A successful surgical repair of acute postinfarction mitral papillary muscle rupture].

We reviewed a case who underwent early operation for acute postinfarction papillary muscle rupture. The patient was a 75-year-old male who was admitted to our hospital with cardiogenic shock required endotracheal intubation and intraaortic balloon support. The period to operation was 6 days from the onset of inferior myocardial infarction, and 2 days from the onset of postinfarction papillary muscle rupture. The posterior papillary muscle of mitral valve was totally ruptured and the mitral valve was replaced with a mechanical prosthesis (SJM 27 mm). Postoperative clinical course was not smooth, but the patient was going well. We believe to get good results for early operations of postinfarction papillary muscle rupture unless operative chances were lost.

Aged↗
PubMed1992

[The long-term prognosis of coronary artery bypass surgery--the influence of preoperative left ventricular volume on the prognosis of cardiac death].

We have assessed the long-term prognosis about cardiac death of isolated coronary artery bypass surgery from 1972 to 1988 in 361 consecutive patients. The duration of follow-up were from 0.4 years to 14.6 (mean 5.7) years. Of the 361 study patients, the operative morality was 4.7% (17 patients) and 29 patients (8.0%) died during follow-up, 11 (3.0%) of which were from cardiac causes. Actuarial survival rate was 85.2% at 10 years after surgery. The 10 year-survival rate was similar for patients with single, double, triple vessel disease, and left main trunk disease (94.5%, 83.7%, 75.1% and 89.1%, respectively). For patients with and without old myocardial infarction, the 10 year-survival rate was significantly different (75.4% and 93.3%, respectively) (p less than 0.005). In order to detect which factors of preoperative cardiac function among cardiac index, LV end-diastolic pressure, LV end-diastolic volume index, LV end-systolic volume index, and LV ejection fraction influenced the long-term prognosis, multivariant regression analysis was performed. Only LV end-systolic volume index was a significant factor, and the discriminative point was 50 ml/m2. For patients with LV end-systolic volume index less than 50 ml/m2 and greater than or equal to 50 ml/m2, the 10 year-survival rate was significantly different (88.3% and 32.9%, respectively) (p less than 0.005). In conclusion, the most significant factor influencing longterm prognosis after coronary artery bypass surgery was left ventricular end-systolic volume, indicating the importance of preventing preoperative dilatation of left ventricle.

Actuarial Analysis↗
PubMed1991

Relation between myocardial beta-adrenergic receptor and left ventricular function in patients with left ventricular volume overload due to chronic mitral regurgitation with or without aortic regurgitation.

The relation between myocardial beta-adrenergic receptor and left ventricular (LV) function was studied in 10 patients, aged 41 to 61 years (average 51), with LV volume overload mainly due to chronic mitral regurgitation. Beta-adrenergic receptors were examined using crude membrane in LV papillary muscle obtained at mitral valve replacement. Cardiac function was evaluated at preoperative cardiac catheterization with the interval to surgery of 1 to 33 months (average 7). Beta-adrenergic receptor density in 7 patients with New York Heart Association class II or III congestive heart failure was higher than that in 3 patients with class IV heart failure (59 +/- 19 vs 37 +/- 3 fmol/mg protein, p less than 0.05). Beta-adrenergic receptor density showed a positive correlation with end-systolic stress/end-systolic volume index ratio, the index for contractile function (p less than 0.005). Other parameters such as cardiac index, pulmonary artery wedge pressure and LV ejection fraction had no significant correlation to beta-adrenergic receptor. The results demonstrated that increases in symptom and LV dysfunction, particularly of the contractile state, was associated with decreased myocardial beta-adrenergic receptor density from possible down-regulation in patients with chronic mitral regurgitation with or without aortic regurgitation.

Adult↗
PubMed1991

A new angled transducer for intraoperative epicardial echocardiography.

We tested a new angled transducer developed for intraoperative epicardial echocardiography in 42 patients. This small transducer, 70 x 20 x 15 mm in size, demonstrated superior operability and provided adequate two- or four-chamber imaging from the apical approach, which may lead to high-quality assessment with two-dimensional Doppler flow imaging.

Adolescent↗
PubMed1991

Evaluation of right ventricular function using gated equilibrium blood pool radionuclide ventriculography in patients with congenital volume and pressure overload late after surgical repair.

The effects of congenital right ventricular pressure and volume overload were studied in 3 patients with pulmonary stenosis, 7 with atrial septal defect and 6 with atrial septal defect plus pulmonary stenosis late after successful surgical correction. Gated equilibrium blood pool radionuclide ventriculography was used to measure right ventricular function at rest and during exercise and to compare it with eight normal subjects. Right ventricular ejection fractions at rest and during exercise were measured to be 61 +/- 9% and 66 +/- 13%, respectively, in the group with pulmonary stenosis, 49 +/- 7% and 54 +/- 8% in the group with atrial septal defect, and 65 +/- 13% and 69 +/- 13% in the group with atrial septal defect plus pulmonary stenosis. The values in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis were significantly higher than the control subjects (45 +/- 5% and 51 +/- 5%, p less than 0.01). The peak filling rate at rest and during exercise was also significantly higher in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis than in controls (at rest, 2.72 +/- 0.72, 2.53 +/- 0.94 vs. 1.64 +/- 0.24 p less than 0.05; during exercise, 4.38 +/- 1.23, 4.13 +/- 1.18 vs. 2.52 +/- 0.62, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗