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Biomedical subjects

K Nojima

Publications and source records attributed to K Nojima.

At least 55 records · Page 3Linked to original sources
PubMed1993

[A large vertebrobasilar junction aneurysm grown at the proximal end of basilar artery fenestration--usefulness of balloon occlusion test with 99mTc-HMPAO SPECT under induced hypotension and consideration in therapeutic strategies].

A 48-year-old lady suffered a transient loss of consciousness. CT and MRI revealed a large vascular lesion compressing the left lower pons. Angiography revealed a large aneurysm at vertebro-basilar junction, dome of which projected anteriorly and left to midline. Her previous vertebral angiogram taken 10 years ago when she suffered a subarachnoid hemorrhage from the left MCA aneurysm, had showed a fenestration of lower basilar artery without apparent aneurysm. Bilateral super-selective vertebral angiograms revealed that the aneurysm arose at the proximal end of the fenestration, and vertebrobasilar junction was incorporated into the aneurysm indicating broad neck aneurysm. The left posterior communicating artery was well developed. Balloon test occlusion (BTO) of bilateral vertebral artery was performed under normotension and induced hypotension. 99mHM-PAO SPECT was used to examine cerebral blood flow (CBF) during hypotensive BTO. The patient tolerated the test and CBF imaging showed insignificant sight decrease in bilateral cerebellar hemispheres. Exploration of the aneurysm was carried out by the right far lateral suboccipital approach. Bilateral vertebral arteries and the right segment of the basilar artery fenestration were identified. Neck clipping of the aneurysm with reconstruction of the parent vessels were tried with fenestrate clip. However, narrow operative field and large dome of the aneurysm made it hard to identify the left segment of the fenestration. Neck clipping was given up and clipping of bilateral vertebral arteries were performed distal to posterior inferior cerebellar artery with three body clippings. The patient showed moderate postoperative left lower nerve palsy, which was gradually improved in several weeks. Follow-up angiography revealed no opacification of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Basilar Artery↗
PubMed1992

[An experience of rapid, two-stage arterial switch operation for transposition of the great arteries and intact ventricular septum beyond the neonatal period].

A 2-month-old girl with transposition of the great arteries and intact ventricular septum was successfully repaired by rapid, two-stage arterial switch operation. Balloon atrioseptostomy and ligation of the ductus arteriosus was done elsewhere on 14th and 29th day after birth. On her first admission to our hospital at 2 months of age, left ventricular-right ventricular pressure ratio (LVp/RVp) was almost 0.5 and left ventricular posterior wall thickness (LVPWT) by echo cardiography was 3.5 mm. Because of these date, we selected rapid, two-stage arterial switch operation. On 74 days, the first-stage preparatory operation (pulmonary arterial banding and right modified Blalock-Taussig shunt) was undergone with the resultant LVp/RVp of 0.97. During a few days after the first-stage operation, left ventricular ejection fraction (LVEF) by echocardiography was reduced to nearly 30%. But after this phase left ventricular function recovered rapidly and LVp/RVp, LVPWT and LVEF was 1.18, 6.3 mm and 66% on the 7th day. On the 9th day, the second-stage arterial switch operation was undergone as usual as in neonatal period without hard adhesion. Her postoperative course was uneventful.

Cardiac Surgical Procedures↗
PubMed1991

A quantitative analysis of hemodynamic effects of the right ventricle included in the circulation of the Fontan procedure.

BACKGROUND: Right heart hemodynamics were analyzed with a catheter-mounted velocity meter in seven patients after direct atrioventricular anastomosis for Fontan procedure (RV group) and were compared with those obtained in eight patients after direct atriopulmonary anastomosis (RA group). METHODS AND RESULTS: In the RV group, cardiac output was 2.7 +/- 0.6 l/min/m2; mean right atrial and pulmonary artery pressures were both 13 +/- 3 mm Hg; mean pulmonary artery wedge pressure was 7 +/- 5 mm Hg; left ventricular end-diastolic volume, determined angiographically, was 129 +/- 40% of normal; and its ejection fraction was 0.50 +/- 0.09. In the RA group, data were similar to those of the RV group except that right heart pressure were lower in the RV group, which was related to the preoperative condition of the pulmonary circulation. In the RV group, the fraction of ventricular forward flow of the total forward flow in the main pulmonary artery ranged from 0.21 to 0.46 and was not correlated with cardiac output or with any other parameter. The backward flow into the inferior vena cava at ventricular systole was greater than the atrial flow in two patients in whom cardiac output was less than 2.2 l/min/m2, whereas caval backward flow at atrial contraction was greater than ventricular flow in the other five patients, of whom four had a cardiac output greater than 3.1 l/min/m2. CONCLUSIONS: We conclude that the inclusion of right ventricle in the circulation of the Fontan procedure does not necessarily improve overall hemodynamics in most patients.

Adult↗
PubMed1991

[Absent pulmonary valve syndrome: surgical approach for the worst group included in symptomatic neonates].

Absent pulmonary valve syndrome (APVS) has been classified to two groups. One is severely symptomatic infant group and the other no or slightly symptomatic. But we think that severely symptomatic group should be divided into the worst neonate group and the other. This worst group, that contains neonates who can not be weaned from the respirator after surgical intervention including corrective surgery because of severe bronchomalacia and/or peripheral bronchial stenosis, has already severe respiratory distress and needs ventilatory support while high pulmonary vascular resistance is maintained. Three patients of this group were operated on at 2, 13 and 2 days of age and there were two late hospital death. The last patient underwent ligation of main pulmonary artery (mPA) and left modified Blalock-Taussig shunt (MBTS) with phi 4 mm polytetrafluoroethylene graft and was extubated on the next day. The management of this group should aim at controlling the pulmonary regurgitation as early as possible to decrease the progressive airway obstruction and minimize pulmonary tissue damage. Ligation of mPA and MBTS can be performed without cardiopulmonary bypass and eliminates pulmonary regurgitation and controls the pulmonary blood flow less than the total correction. In the point of protecting bronchi and lung and reducing the risk of surgical intervention in critical neonatal period, ligation of mPA and MBTS can be safer and more effective operation for the worst APVS neonate than the total correction with insertion of artificial valve.

Blood Vessel Prosthesis↗
PubMed1990

Influence of dorsal hippocampal stimulation and dorsal fornix lesions on hepatic glucose metabolism in rabbits.

We examined the effects of stimulation of the dorsal hippocampus and lesions of the dorsal fornix on glucose metabolism in liver slices of rabbits. Hippocampal stimulation decreased the 14C transfer rates from 14C-glucose into CO2, ketone bodies, cholesterol ester and free fatty acids, but increased the rates into triglyceride, phospholipids and glycogen. Fornix lesions had various effects on glucose metabolism, and the effects of hippocampal stimulation on glucose metabolism were abolished by fornix lesions. These observations support the hypothesis that the hippocampus is an integral part of the brain regulator system in the hepatic glucose metabolism.

Animals↗
PubMed1989

Inotropic effect of phenylephrine and myocardial alpha-adrenergic receptor in newborn and adult animals.

Developmental changes in the myocardial alpha-receptor density were studied using rabbit, rat and dog hearts. In all species studied, alpha-receptor density in the newborn was greater than in the adult. The inotropic effect of phenylephrine was measured using the isolated arterially perfused heart preparation of rabbit and rat. The heart was stimulated electrically at 40/min. In the presence of propranolol, phenylephrine caused a significant positive inotropic effect which was significantly less in the newborn than in the adult. Since alpha-adrenergic stimulation activates protein kinase C, the inotropic effect of protein kinase C activation was studied in the rabbit and rat using phorbol myristate acetate (PMA). PMA caused a negative inotropic effect and the decrease in contractile function in the newborn was greater than in the adult. These data suggest that myocardial alpha-receptor density decreases and the positive inotropic effect of alpha-agonist increases with development. The reasons for this discrepancy remain unclear but there may be developmental differences in the signal transduction processes of alpha-stimulation. The greater negative inotropy of protein kinase C activation in the premature heart may be one of the mechanisms of the reduced inotropy of alpha-agonist in this age group.

Animals↗
PubMed1988

Determination of 17-hydroxyprogesterone in plasma by gas chromatography-mass spectrometry with high-resolution selected-ion monitoring.

A method for determining 17-hydroxyprogesterone in plasma by isotope dilution-mass spectrometry is described. For the internal standard 17-hydroxy [2H4]progesterone is used. Extraction of plasma is followed by conversion into the 3,20-dienol,17-tristrimethylsilyl ether derivative and analysis by capillary gas chromatography-mass spectrometry with selected-ion monitoring, at a resolution of 6000. The lower limit of quantitation was 1 pg, judged from a criterion of a signal-to-noise ratio of 10. The precision and accuracy of the method were satisfactory.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Influence of microinjection of corticosterone into hippocampus on hepatic acetate metabolism in rabbits.

Corticosterone was injected directly into the hippocampus of rabbits, and changes in hepatic acetate metabolism were studied. The microinjection of corticosterone with seasame oil into hippocampus decreased the rates of 14C transfer from 14C-1-acetate into CO2 and free cholesterol, and increased 14C transfer into glucose, ketone bodies, triglyceride, free fatty acids and phospholipids. But after microinjection of corticosterone into the hippocampus of rabbits with lesions of dorsal fornix, hepatic acetate metabolism did not differ from that of control rabbits, which received injection of seasame oil into the same brain region. From these results it might be suggested that the hippocampus is a part of corticosterone-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1988

Criteria for two-staged arterial switch operation for simple transposition of great arteries.

We analyzed hemodynamic variables in patients with transposition of the great arteries with intact ventricular septum (simple transposition) after pulmonary artery banding and Blalock-Taussig anastomosis to establish the criteria for two-staged arterial switch operation. The study included 35 patients who underwent the switch operation after banding and anastomosis; two died shortly after surgery, and one died of tachycardia 31 days after the operation. The left-to-right ventricular pressure ratio was above 0.83 in all surviving patients, 0.68 and 0.63 in the two operative deaths, and 0.84 in the other death. In the 32 surviving patients, angiographically determined left ventricular (LV) end-diastolic volume and ejection fraction averaged 147 +/- 46(SD)% of normal and 0.64 +/- 0.12, respectively. We also measured LV mass using angiographic LV semiaxes and end-diastolic LV posterior wall thickness obtained from an echocardiogram. These variables of the patients who died were not different from those of the surviving patients. The wall thickness was greater than 4 mm in the surviving patients, while it was 3.5 mm in the two patients who died early and 5 mm in the patient who died later. From the semiaxes, the wall thickness, and aortic diastolic pressure, all of which were obtained before the anatomic repair, we calculated the predictive LV wall stress. This wall stress would indicate the LV wall stress at the time of aortic valve opening immediately after the arterial switch operation. Predictive wall stress was less than 120 x 10(3) dynes/cm2 in all but one of the surviving patients, whereas it was 151, 153, and 186 x 10(3) dynes/cm2 in the three patients who died.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1987

Lateral hypothalamic region excites the activity of vasopressin neurons in the supraoptic nucleus through subfornical organ neurons.

In urethane-anesthetized male rats, microinjection of angiotensin II into the lateral hypothalamic area excited the activity of about half (N = 7) of subfornical organ neurons (N = 15) antidromically identified as projecting to the hypothalamic supraoptic nucleus. Microinjection of angiotensin II also excited the activity of approximately one-quarter (N = 8) of putative vasopressin-secreting neurons (N = 28) in the hypothalamic supraoptic nucleus and these excitatory responses of putative vasopressin-secreting neurons were blocked (N = 3) or attenuated (N = 3) by pretreatment with the angiotensin II antagonist saralasin, but not by isotonic saline (N = 2), in the subfornical organ.

Action Potentials↗
PubMed1987

Flow dynamics in the main pulmonary artery after the Fontan procedure in patients with tricuspid atresia or single ventricle.

We analyzed the flow velocity pattern in the main pulmonary artery after Fontan operation in patients with tricuspid atresia (n = 10) or with single ventricle (n = 10) by means of a catheter-mounted velocity probe. The area underneath the velocity signal of the forward flow was integrated, and ratios of the portions during atrial systole and during the diastolic phase to the total area (Fa and Fd) were calculated. The Fa was 0.54 +/- 0.09 in patients with tricuspid atresia and 0.45 +/- 0.05 in those with single ventricle (p less than .01). Cardiac output, obtained by the thermodilution method, was 2.45 +/- 0.48 liters/min/m2 in patients with tricuspid atresia and 2.75 +/- 0.72 liters/min/m2 in those with single ventricle. The forward flow during atrial contraction, calculated by multiplying Fa by cardiac output, was 1.32 +/- 0.35 liters/min/m2 in patients with tricuspid atresia and 1.23 +/- 0.33 liters/min/m2 in those with single ventricle. The diastolic forward flow, calculated from Fd and cardiac output, was 0.99 +/- 0.25 liter/min/m2 in patients with tricuspid atresia and 1.52 +/- 0.45 liters/min/m2 in those with single ventricle (p less than 0.005). The sum of cross-sectional areas of the right and left pulmonary arteries normalized by body surface area (PA index) was 282 +/- 85 cm2/m2 in patients with tricuspid atresia and 462 +/- 65 cm2/m2 in those with single ventricle (p less than .005). The Fa was inversely correlated with the PA index in the whole group (r = -.69) and also in the tricuspid atresia group alone (r = -.87).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1986

The applicability of noninvasive His bundle electrogram to assessing the effect of digitalis on atrioventricular conduction.

His bundle electrograms were recorded by a signal averaging technique using the Takayasu vectorial lead system, and effects of ouabain on the atrioventricular conduction were investigated using Wistar rats. Ouabain was given intraperitoneally at 30 min intervals in doses of 1-40 mg/kg. When ouabain dosage was increased to 20 mg/kg, the prolongation of PQ interval became prominent and P waves were hidden on the preceding T waves. Dose-related prolongation of PQ and AH intervals was observed in the 1-15 mg/kg dosages. Ouabain-induced ventricular arrhythmias occurred in the 30 mg/kg dosage. Dose-related prolongation of QRS duration and HV interval was observed in the 1-25 mg/kg dosages. These prolongations were significant by the analysis of variance (p less than 0.01). Prolongation of PQ and AH intervals is probably due to a digitalis-induced increase in parasympathetic nerve activity. However, the reason for the prolongation of HV interval and QRS duration was uncertain. Direct effects of ouabain on the conduction system, or central nervous system effects of ouabain on cardiovascular function were speculated. These results suggest the applicability of the noninvasive record of His bundle electrogram to assessing the digitalis effect even on the human atrioventricular conduction.

Animals↗
PubMed1986

Clinical characteristics of myocardial infarction following Kawasaki disease: report of 11 cases.

Between 1979 and 1984, 11 patients with myocardial infarction following Kawasaki disease were seen in our hospital. There were seven boys and four girls, aged from 3 months to 6 years. This cardiovascular complication developed in the early stage, from 19 days to 6 months of illness, in all but three patients. Significant clinical symptoms were recognized in only five patients. Two patients died, the conditions of two are well controlled with anticongestive therapy, and the remaining patients are asymptomatic. The diagnosis of myocardial infarction was confirmed by the following clinical findings: typical ECG patterns (10/11), abnormality of the left ventricular wall movement by serial two-dimensional echocardiography (9/10), elevated value of cardiac enzymes (6/6), perfusion defect by thallium 201 myocardial scintigraphy (6/8), and coronary artery occlusion or ventricular aneurysm by angiocardiography (9/9). All patients had markedly dilated and multiple coronary aneurysms during the course of the illness. Because myocardial infarction is frequently associated with the rapidly dilating coronary artery during the acute stage, ECG monitoring, preparation of resuscitation equipment, and use of antithrombotic agents are recommended for those high-risk patients. When a myocardial infarction has been diagnosed, measures including cardiac monitoring, use of vasodilators, inotropic agents, and urokinase may be valuable.

Aneurysm↗
PubMed1985

Repeated quantitative angiograms in coronary arterial aneurysm in Kawasaki disease.

Accurate evaluation of the extent of coronary artery lesions complicating Kawasaki disease is clinically important in patient management. Based on a total of 188 coronary angiograms and retrospective follow-up observations, the condition of coronary aneurysms was quantitatively graded as: 0 (normal)--no significant enlargement in any portion of the coronary artery; I (mild)--aneurysmal dilatation of the coronary artery evident but localized, with a maximal diameter of less than 4.0 mm; II (moderate)--maximal diameter of coronary aneurysms between 4.0 and 8.0 mm, regardless of body size; III (severe)--giant aneurysms, with the maximal diameter greater than 8.0 mm. Most mild coronary aneurysms regressed to normal within a short time, and the patient's prognosis was good. The course of grade II aneurysms varied, depending on initial angiographic coronary diameter, but all were eventually reduced in coronary size. In contrast, grade III aneurysms usually progressed to become obstructive or stenotic coronary lesions, or the large aneurysm persisted. Follow-up observations revealed that the course of coronary artery disease depended on the size and distribution of aneurysms at initial angiography. This grading of the severity of coronary lesions may provide useful criteria for predicting the prognosis of patients with Kawasaki disease.

Aneurysm↗
PubMed1985

Noninvasive recording of His bundle electrograms using vectorial leads system.

His bundle electrograms were recorded in 8 rats by a signal averaging technique using the Takayasu vectorial lead system. Animals were anesthetized and placed in the prone position. The polarity of three orthogonal leads were: the X axis, from right to left; the Y axis, from top to bottom; the Z axis, from back to front. Potentials from the X, Y, and Z leads were amplified by 20,000 with high-pass 12 dB/octave filtering at 80 Hz, and signal averaging of 2000 beats was performed at a sampling interval of 100 microseconds. The His bundle potential could be clearly defined in all 8 rats. The mean amplitude of the His potential was larger in the X-axis (23.6 +/- 9.2 mu V) or the Y-axis (28.4 +/- 14.5 mu V) than the Z-axis lead (11.5 +/- 8.6 mu V). Directions of the His potential vectors were to the left in 5 of 8 rats (62.5%), to the caudal in 4 of 6 rats (66.7%), and to the dorsal site in 6 of 8 rats (75.0%). This vectorial lead system, devised in accordance with McFee and Johnston's theory on lead field, was useful for recording His bundle electrograms.

Animals↗
PubMed1985

Left ventricular systolic function in children with coronary arterial lesion following Kawasaki disease.

Seventy-five children with Kawasaki disease underwent quantitative left ventricular cineangiography, and angiographic measurements were made to obtain left ventricular ejection fraction (LVEF) and mean velocity of circumferential fiber shortening (mVcf). In addition, left ventricular pressure and echocardiograms were taken simultaneously before and after nitroprusside infusion using a micromanometer. In the present study, the slope of the line describing end-systolic pressure-diameter relations (Emax) was calculated. The 75 children with Kawasaki disease were classified into five groups according to the severity or condition of associated coronary lesions: Grade 0 group (normal--no significant enlargement of the coronary artery is seen), grade 1 group (mild state of lesion--the maximum diameter of the coronary artery is 4.0 mm or less), grade 2 group (moderate state of lesion--the maximum diameter of the coronary artery is 4.0-8.0 mm), grade 3 group (serious state of lesion--the maximum diameter of the coronary artery is 8.0 mm or over, i.e., giant aneurysm), and stenotic lesion (SL) group (myocardial infarction or various other stenotic lesions are involved). Each group was investigated for each index of left ventricular function. In the grade 2 group, the averaged value of LVEF was slightly smaller than those for the grade 0 and 1 groups, while in the grade 3 and SL groups, the averaged values of LVEF were markedly smaller than those for all other groups. Grade 3 and SL groups showed averaged mVcf values that were smaller than those for other groups, while grade 2-3 and SL groups showed averaged values of Emax that were markedly smaller than those for the remaining groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneurysm↗