Search PubMed⌕ Search

Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 1,045 records · Page 58Linked to original sources
PubMed1985

[Mechanism of systolic anterior motion and left ventricular outflow obstruction in hypertrophic obstructive cardiomyopathy].

Two-dimensional echocardiographic studies were performed for 22 patients with asymmetric septal hypertrophy and systolic anterior motion (SAM) of the mitral valve to clarify the mechanism of SAM and left ventricular outflow obstruction. The long-axis view of the left ventricle showed that a distal portion of the anterior mitral leaflet became surplus when the mitral valve was closed in 15 of 16 patients with SAM-septal contact and in four of six patients without it. In these patients, the mitral leaflet coaptation was displaced anteriorly, and/or the anterior leaflet was elongated, showing an anterior motion. In an unusual patient with SAM-septal contact, a distal portion of the long posterior mitral leaflet was surplus. The remaining two patients without SAM-septal contact had a rather widely coapted portion of the mitral leaflets. The distal surplus portion and the coapted portion of the mitral valve were displaced anteriorly prior to the onset of ejection, and moved forward and protruded into the outflow tract more rapidly and more excessively than the papillary muscles during early to mid systole in all patients. Then, the distal mitral valve and the chordae tendineae adopted the configuration of an inverted V in mid systole. The tip of the surplus leaflet contacted the interventricular septum in patients with SAM-septal contacts. In the short-axis view of the left ventricle, the central portion of the distal mitral valve moved forward excessively and bent like an inverted U during early to mid systole. Therefore, SAM of the distal mitral valve is thought to be caused by the hydrodynamic force generated by the ejection flow. This force is supposed to be not only due to the Venturi effect, but is more properly understood as a "pushing force". Left ventricular outflow obstruction is considered to be formed by the protruding distal mitral valve and the hypertrophied septum.

Adolescent↗
PubMed1985

[Echocardiographic features of small heart].

To clarify the clinical significance of a small heart; i.e., a small cardiac silhouette on chest radiography, an echocardiographic study was performed. Sixty persons with small heart according to cardiothoracic ratios less than or equal to 40%, and 23 age- and sex-matched normal controls (42% less than cardiothoracic ratio less than or equal to 50%) received two-dimensional and M-mode echocardiography. The body weights and body surface areas (BSA) in the small heart group were significantly less than those in the control group. On the lateral chest radiographs, numerous cases with small heart had straight spines and chests with decreased anteroposterior diameters. More than half of the small heart group had a variety of cardiovascular complaints, including chest pain, palpitation, dyspnea, and dizziness. Echocardiographic measurements were performed and hemodynamic indices were calculated. The results were as follows: Left ventricular dimension at end-diastole (LVDd), left ventricular dimension at end-systole (LVDs), left atrial dimension (LAD), and left ventricular mass (LV mass) of the small heart group were significantly less than those of the control group. There were, however, no differences in the values corrected by BSA (LVDd/BSA, LVDs/BSA, LAD/BSA and LV mass/BSA) between the two groups. We found no differences in hemodynamic indices (heart rate, stroke volume, ejection fraction, and cardiac output) at rest between the small heart and control groups. Nineteen cases (32%) had mitral valve prolapse (MVP) on echocardiography in the small heart group. Characteristic phonocardiographic findings were found in 11 cases with MVP (systolic click in four, mitral regurgitant murmur in three, and both in four).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Coronary sinus type atrial septal defect diagnosed by two-dimensional color Doppler echocardiography: a case report].

This is a case report of coronary sinus type atrial septal defect (ASD) diagnosed preoperatively by two-dimensional color Doppler echocardiography. A 22-year-old asymptomatic woman was admitted for preoperative cardiac evaluation. A cardiac murmur and cardiomegaly had been noted at a routine examination which included electrocardiography and chest radiography, and M-mode echocardiography suggested the presence of a secundum type ASD. Color Doppler echocardiography revealed a left to right atrial shunt flow through the coronary sinus ostium into the right atrium. By peripheral contrast echocardiography, a negative contrast echo from the coronary sinus ostium was observed within the right atrium and persistent left superior vena cava was excluded. At operation, a 2 X 3 cm defect was demonstrated at the interatrial septum in the vicinity of the coronary sinus ostium. This is the first reported case of a coronary sinus type ASD diagnosed preoperatively by color Doppler echocardiography.

Adult↗
PubMed1985

[The effects of aorto-coronary bypass grafting to totally occluded coronary arteries on left ventricular contractility].

The effects of aorto-coronary bypass grafting (ACBG) on totally occluded coronary arteries (TOCA), postocclusion vessels of which were demonstrated angiographically through collaterals and left ventricular contractility were studied in eleven patients consisted of nine with transmural myocardial infarction (TMMI) on ECG in the area perfused by TOCA and without TMMI. Of eleven ACBG consisting of eight left anterior descending coronary arteries (LAD) and three right coronary arteries (RCA), all eight grafts to LAD were patent, whereas two of three to RCA were obstructed on the postoperative angiogram. The following evaluations were undertaken in the cases with patent grafts. In seven cases with TMMI (six LAD, one RCA), left ventricular ejection fraction (EF) increased from 0.56 +/- 0.08 (Mean +/- SD) to 0.65 +/- 0.07 (p less than 0.01). PLVSP/LVESV slightly increased, but not significantly. Mean Vcf increased from 1.07 +/- 0.33 to 1.83 +/- 0.88 circ/sec (p less than 0.02). Left ventricular segmental wall motion also improved from 23.1 +/- 6.8 to 29.5 +/- 7.2% (p less than 0.01), markedly in the anterior and apical segment. In two cases without TMMI, all of EF, PLVSP/LVESV, Mean Vcf and segmental wall motion improved much more than the cases with TMMI. In conclusion, it was suggested that ACBG to TOCA, especially LAD visualized angiographically through collaterals resulted in the excellent graft patency rate and the significant improvement of left ventricular contractility, even in the cases with TMMI.

Adult↗
PubMed1985

[Prolonged action preparation of cefaclor].

This study was conducted to develop a prolonged action preparation of cefaclor (CCL) which can offer, with the twice-a-day administration, as much effectiveness as its conventional preparation (Kefral capsule) with the 3 times-a-day administration. Absorption site of CCL in gastrointestinal tract, preparation form (enteric coated granules) which slowly release CCL, dissolution property of the form, and mixed ratio of the form and rapid release form (nonenteric coated granules) were studied and complex granules consisting of 40% of nonenteric coated granules and 60% of enteric coated granules which dissolve at pH 6 were chosen as a prolonged action preparation of CCL. Bactericidal activity of the prolonged action preparation (S6472) was confirmed to be the same as that of the conventional preparation by comparative viable cell count study in which concentrations of CCL simulated to plasma concentrations following the administration of S6472 at the dosage of 375 mg b.i.d. and the conventional preparation at the dosage of 250 mg t.i.d. were used. From the above, S6472 is considered to be a prolonged action preparation of CCL which serve our purpose. Since S6472 can be given with the twice-a-day administration, its daytime administration is not necessary. Therefore, S6472 is considered to be much useful preparation for the patients.

Adult↗
PubMed1985

Distribution of neurotensin in the canine gastrointestinal tract.

The distribution of immunoreactive neurotensin in the canine gastrointestinal tract from the esophagus to the rectum, as well as in the pancreas, was determined by a specific neurotensin radioimmunoassay. Immunoreactive neurotensin was found throughout the gastrointestinal tract and in the pancreas. The highest concentrations of immunoreactive neurotensin were found in the mucosal extracts of the jejunum (422 +/- 68 ng/gm) and ileum (3025 +/- 289 ng/gm). Small but substantial amounts of immunoreactive neurotensin were found in the esophagus, fundus (includes fundus and corpus), antrum, duodenum, colon, and pancreas. The concentrations of neurotensin in the mucosal extracts of the jejunum and ileum increased in a graded fashion from the proximal jejunum to the distal ileum. The neurotensin concentration in extracts of the seromuscular layers of jejunum (73 +/- 14 ng/gm) and ileum (187 +/- 38 ng/gm) were statistically higher in comparison with other gut loci.

Animals↗
PubMed1985

[Some practical problems and several methodological trials in continuous intracranial pressure monitoring].

The continuous intracranial pressure monitoring has been widely applied in intensive or critical care, but there are various kinds of methods for its monitoring at present. One hundred and forty-one cases mostly with severe head injury were subject to the intracranial pressure recordings in the critical care ward in Department of Emergency Medicine, University of Tokyo Hospital, from October, 1980 through May, 1983, and in Neurosurgical Unit, Showa General Hospital, in April and May, 1984. The authors made several methodological trials for the monitorings in them and compared with one another from the aspect of clinical practice. The subarachnoid catheter was inserted into the subarachnoid or sometimes into the subdural spaces by way of the burr hole in 112 cases and proved not to demonstrate in some cases the intracranial pressure waves clearly due to so called damping phenomenon but to indicate the reliable values, or trustworthy mean pressures in all the cases except for impending brain dead patients with swollen hemispheres and least cerebrospinal fluid remained in intracranial subarachnoid spaces. The ventricular fluid pressure was monitored in nine cases and was most dependable as well as the subarachnoid pressure. The ventricular cannulation and its maintenance were, however, difficult when the ventricles were compressed or deviated, which were often experienced in acute severe head injury and also in impending brain death just because of the same above mentioned reasons. These demerits were attempted to be conqured with epidural pressure monitorings such as the fiberoptic sensor (Ladd) in 17 cases, the intracranial catheter tip pressure transducer (Gaeltec) in nine cases and the sensor of bioimplantable polymer (Plastimed) in three cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Importance of the ileum in neurotensin released by fat.

Neurotensin is a potent stimulant of pancreatic exocrine secretion. Ileal mucosa is the storage site for about 90% of total neurotensin. Release occurs rapidly after a fatty meal and during perfusion of the duodenum and jejunum with fat but not during perfusion of the ileum with fat. To determine the origin of neurotensin released after fat stimulation, we studied the pattern of release of neurotensin before and after resection of the distal two thirds of the small bowel. Six dogs with gastric and duodenal fistulas were studied on different days. All dogs received infusions (in random order) of intraduodenal corn oil (Lipomul) (3 ml/kg/hr) and intravenous calcium chloride (0.36 mmol/kg intravenous bolus, followed by 0.36 mmol/kg/hr infusion) before and 6 weeks after resection of the distal two thirds of the small bowel with preservation of the ileocecal valve. Plasma levels of neurotensin were measured by specific radioimmunoassay. We found that release of neurotensin, in response to both intraduodenal Lipomul and intravenous calcium chloride stimulation, was abolished by resection of the distal small bowel. Before surgery, Lipomul-stimulated release of neurotensin rose to a peak concentration of 51 +/- 17 pg/ml at 30 minutes. After surgery there was no release (the levels were unchanged from basal). Before surgery, intravenous calcium chloride produced a peak release of neurotensin (52 +/- 15 pg/ml) 2 minutes after bolus injection. After surgery, neurotensin was not released by intravenous calcium. We conclude that the source of neurotensin released by perfusion of the proximal gut and by intravenous calcium infusion is the ileum. The release of neurotensin from the distal gut appears to be dependent on a signal from proximal to distal gut. The identity of the signal is unknown but is either a nerve reflex or a peptide agent.

Animals↗
PubMed1985

[Chloride and lactate composition of hypertonic sodium solution for fluid resuscitation of burn injury].

This study was performed to determine the appropriate anion composition of hypertonic sodium solution for fluid therapy of severely burned patients. Two different solutions with equal sodium concentration (Na 300 mEq/1) were prepared. The first one, low chloride solution (C1 88 mEq/1), was used for ten patients (group I); the second, high chloride solution (C1 244 mEq/1), for other ten patients (group II). Two groups had the same severity of burn injury. The infusion rate was controlled to achieve an adequate urine output (1.0 ml/kg/hour). The observation period was eight hours after injury and water and sodium intake and renal function were measured. Ccr and FENa were identical in two groups. Although both had same urine output, CH2O of group I increased. Water and sodium intake of group I were lower than those of group II. Water diuresis was related with limited chloride intake in group I and this suggested the relation between urine concentration and chloride loading in kidney. conclusively, hypertonic sodium solution with low chloride concentration requires less volume for resuscitation and may be preferred to high chloride solution in the initial therapy of burn injury.

Acid-Base Equilibrium↗
PubMed1985

[Pulsed Doppler echocardiography and pharmacodynamic phonocardiography in the diagnosis of silent aortic regurgitation: a correlative study].

To determine the usefulness of pulsed Doppler echocardiography (PDE) in diagnosing aortic regurgitation (AR), the following two studies were performed. PDE and phonocardiography (PCG) were evaluated for the diagnosis of AR in 36 patients for whom angiography was performed. In 24 patients with grade 2 to 4 by Sellers' classification, all PDE studies were positive for AR (sensitivity of 100%) and PCG studies were positive in 21 patients (sensitivity of 88%). Among 10 patients of grade 1, PDE studies were positive for eight (sensitivity of 80%) and PCG studies were positive for seven (sensitivity of 70%). Angiography was negative for AR in two PCG-proven cases, and PDE also proved AR in one of these. Thus, in all patients, the sensitivity of PDE and PCG were 94 and 82%, respectively. These results indicate that AR may be missed during auscultation, or even when using the latest type PCG. The ability of detecting silent AR was studied in 160 consecutive patients with AR. PDE was positive for AR in 156 of 160 consecutive patients who were diagnosed as having AR by PDE or PCG. In the remaining four patients, three were diagnosed by PCG alone and one by pharmacodynamic phonocardiography using methoxamine (ME-PCG). On the other hand, in 137 of 160, Ar was proven by PCG, and the remaining 23 were so-called "silent AR". ME-PCG was performed for 11 cases of silent AR, but an unequivocal AR murmur was detected in only five. Therefore, the sensitivity of PDE in diagnosing silent AR was 96 percent, while that of ME-PCG was only 45 percent. Thus, compared to PCG and even pharmacodynamic PCG, PDE is a much more sensitive method of diagnosing AR. However, in mild AR cases, angiography, PDE and PCG, all have some limitations in diagnosing AR.

Adult↗