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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 415 records · Page 23Linked to original sources
PubMed1985

The mechanism of dNTP-unbalanced cell death induced by 5-fluorouracil and its derivatives.

The mechanism of 5-fluorouracil (5-FU) and 5-fluorodeoxyuridine (FdUR)-induced death of mouse mammary tumor FM3A cells was studied. When the cells were exposed to 5-FU or FdUR, an unbalance of intracellular dNTP pool resulted. The unbalance was followed by breakage of mature DNA. DNA double strand breaks were observed in the FdUR (1 microM) treated cells 16 hrs after the administration. We assume that the double strand breaks play an important role in the mechanism of the FdUR-mediated cell death. In addition, the activity that can induce DNA double strand breaks was detected in the lysate of FdUR treated FM3A cells. Since intracellular dNTP pool unbalance seems to be the trigger of these events, this phenomenon may be termed as dNTP-unbalanced cell death.

Animals↗
PubMed1985

[Intraoperative visualization of coronary arteries using two-dimensional echocardiography].

We attempted intraoperative ultrasonic visualization of the coronary arteries of animal models and of patients who underwent coronary artery bypass surgery. Ultrasonic visualization of coronary vessels using a high frequency wide band micro-transducer (3.5-9.0 MHz) was first attempted in three open-chest dogs. The coronary arteries were well visualized from the epicardium with and without contrast perfusion, and the experimentally-occluded portion was well imaged. Subsequently, this technique was clinically applied in two patients undergoing cardiac surgery for valvular and congenital heart diseases, and in nine patients undergoing coronary artery bypass surgery. Gas-sterilized probes were placed directly over the cardiac surface. Ultrasonic imaging of the coronary artery was performed to detect the coronary arteries beneath the fat tissue; image the lesions in coronary vessels, especially those not visualized by angiography; determine the site of bypass grafting and evaluate the graft-ability to the distal branch (the latter was poorly visualized via collateral circulation or not visualized angiographically because of total occlusion at a proximal site); and observe the effects of bypass grafting and intraoperative angioplasty of coronary arteries after these procedures. This ultrasonic technique was found to be useful for the intraoperative evaluation of coronary vessels for coronary artery bypass surgery.

Animals↗
PubMed1985

[Randomized controlled study of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU) in comparison with busulfan for chronic myelogenous leukemia].

UNLABELLED: In a randomized controlled study, the efficacy of MCNU was compared with that of Busulfan in 95 patients with chronic myelogenous leukemia. Of the patients studied, 95 were entered among whom 77 were evaluable. These comprised 40 for an MCNU group (M) and 37 for a Busulfan group (B). No significant difference was found statistically between the two groups with regard to background factors, i.e., male-to-female ratio, age, white blood cell counts, platelet counts, splenomegaly or Ph1 chromosome. RESULTS: CR rate was 83% for M and 68% for B, and the number of days to CR was 88 for M and 155 for B. Blastic crisis was noted in 31% of M patients and 33% of B patients and the number of days to blastic crisis was 542.6 and 581.9, respectively for the two groups. Deaths accounted for 28% and 29% for each of M and B. Side effects were observed in 31% of M cases and 15% of B cases. A significant difference was observed only in the period to CR. MCNU showed almost equal efficacy to that of Busulfan but was superior to Busulfan in patients who required rapid response. Side effects were mild and transient. Despite its delivery by intravenous injection, the administration of MCNU is deemed convenient, considering the long interval possible between treatments, being comparable in this respect with oral Busulfan. MCNU therefore seems a very effective drug for chronic myelogenous leukemia.

Adult↗
PubMed1984

Mechanisms of compensation and decompensation in dilated cardiomyopathy.

Left ventricular (LV) function was evaluated in 32 patients with dilated cardiomyopathy (DC) who underwent cardiac catheterization during the past 6 years (group 4), and the results were compared with the data of 30 normal subjects (group 1). The patients were divided into mildly (group 2, 12 patients) and severely symptomatic subgroups (group 3, 20 patients). DC was characterized by dilated and poorly contracting left ventricle with increased muscle mass, reduced cardiac output and elevated systemic vascular resistance. LV volume was larger, ejection fraction was lower, and end-diastolic and end-systolic stresses were higher in group 3 than in groups 1 and 2. No significant differences were seen in LV muscle mass and wall thickness between groups 2 and 3. A significant inverse correlation was seen between ejection fraction and end-systolic stress in patients with DC (Y = -0.05x + 48.7, r = 0.57, p less than 0.01). The slope of the correlation line between end-systolic stress and volume in DC (Y = 1.20x + 135, r = 0.52, p less than 0.02) was less steep than that of normal subjects (Y = 3.68x + 40, r = 0.64, p less than 0.001). These observations indicate that the primary problem of DC is depressed contractility.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Improvement in left ventricular diastolic function during intravenous and oral diltiazem therapy in patients with hypertrophic cardiomyopathy: an echocardiographic study.

M-mode echocardiography was used to evaluate the acute effect of intravenously administered diltiazem, 10 mg, and the chronic effects of oral diltiazem, 180 mg/day, and propranolol, 60 to 120 mg/day, administered for 2 weeks on left ventricular (LV) systolic and diastolic function in 13 patients with hypertrophic cardiomyopathy. Intravenous injection of diltiazem reduced isovolumic relaxation time from 114 +/- 26 to 99 +/- 21 ms (p less than 0.01) and the time to peak rate of LV dimensional lengthening from 166 +/- 17 to 133 +/- 10 ms (p less than 0.01), without significant changes of LV dimensions or fractional shortening. No significant changes were observed in LV dimensions or fractional shortening, but a significant increase in peak rate of LV dimensional lengthening (from 4.1 +/- 1.5 to 4.8 +/- 1.6/s, p less than 0.05) and a reduction in isovolumic relaxation time (from 105 +/- 26 to 77 +/- 23 ms, p less than 0.01) and the time to peak rate of LV dimensional lengthening (from 156 +/- 23 to 124 +/- 20 ms, p less than 0.01) occurred during the oral administration of diltiazem. In contrast, propranolol caused no significant changes in these values. Thus, diltiazem improves LV relaxation and diastolic filling without altering LV systolic function in patients with hypertrophic cardiomyopathy.

Administration, Oral↗
PubMed1984

[A long-term follow-up study of patients with chronic lymphocytic thyroiditis--with special reference to histological findings].

It is generally believed that in the long-term observation of chronic thyroiditis, the goiter decreases in size with thyroid hormone therapy and the thyroid function drops gradually. On the other hand, the histological changes in so-called Hashimoto's thyroiditis have been recognized to show progressive loss of epithelium and increased fibrosis. In this study, goiter size, thyroid function, thyroid microsomal and thyroglobulin antibodies and histology in needle biopsy were investigated in 75 patients with chronic thyroiditis during an interval of more than ten years. Among 75 cases, 8 (11%) were hypothyroid at the first medical examination. Among 21 cases who received no treatment, 7 (33%) became hypothyroid during the period of more than ten years. Among 54 cases with thyroid hormone therapy, 16 (30%) showed a remarkable reduction in size of goiter, but among 21 cases without thyroid hormone therapy only 3 (14%) showed a remarkable reduction. This paper discusses changes in titers of thyroidal antibodies in 47 cases. Among these 47 cases, 21 increased titer of thyroglobulin antibody during the period of more than ten years. 10 (48%) out of these 21 cases showed a remarkable reduction in size of goiter. But among 11 cases with a decrease of titer of thyroglobulin antibody, only one (9%) showed a remarkable reduction in size of goiter. On the other hand, titer of thyroid microsomal antibody increased in 33 cases. 9 (27%) out of these 33 cases showed a remarkable reduction in size of goiter. Only one (13%) of 8 cases, which decreased titer of thyroid microsomal antibody, showed a remarkable reduction in size of goiter.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1984

A randomized trial of chemoimmunotherapy of acute nonlymphocytic leukemia in adults using a protein-bound polysaccharide preparation.

The effect of immunotherapy with a protein-bound polysaccharide preparation termed PSK on remission duration and survival of adults with acute nonlymphocytic leukemia (ANLL) was studied in a prospective randomized cooperative trial. After having achieved complete remission and receiving a consolidation therapy, 73 patients were randomized either to maintenance chemotherapy or to maintenance chemotherapy plus immunotherapy with PSK. Ultimately 36 patients in the chemotherapy group and 31 in the chemoimmunotherapy group were evaluable. Six months after the last entry, immunotherapy with PSK showed a borderline beneficial effect on remission duration (P = 0.089) and on duration of survival (P = 0.062). When the data were analyzed 12, 18, and 24 months after the last entry there were no significant differences in duration of remission and survival between the two groups. However, analysis of the data of patients who had maintained complete remission for more than 270 days revealed that immunotherapy had a suggestive beneficial effect (P = 0.105), prolonging the 50% remission period by 418 days (885 vs 467 days). Thus, immunotherapy with PSK seems to be active in the treatment of adult ANLL when used for maintenance therapy in combination with chemotherapy, especially in patients with a good prognosis.

Adolescent↗
PubMed1984

Overlapping of the coding regions for alpha and gamma components of penicillin-binding protein 1 b in Escherichia coli.

The mode of biosynthesis of penicillin-binding protein(PBP)-1b in Escherichia coli was investigated by use of the plasmid carrying the ponB(PBP-1b) gene region. Analyses of the products synthesized in minicells and in vitro showed that PBP-1b was synthesized as two molecular species corresponding to the alpha and gamma components of PBP-1b. The coding regions for the alpha and gamma components were located within the ca. 3.7 kb MluI-HincII fragment and transcribed in the direction from the HincII to the MluI site. The capacity for producing the alpha component was abolished by a deletion extending to the MluI site ca. 0.7 kb inward from the HincII end of the ca. 3.7 kb fragment; the remaining 3.0 kb region with the MluI site at both ends directed the production of the gamma component alone. The production of the gamma component was enough to correct all the known defects caused by a ponB mutation. In addition to these results, the analyses for cross-reacting materials produced in correspondence to the various deletions indicated that the coding regions for the alpha and gamma components overlapped and that the N-terminal portion was responsible for the difference between the two components. The distal region about 0.7 kb long inward from the MluI end of the MluI-HincII fragment was dispensable for producing the functional PBP-1b, although the PBP-1b produced was curtailed. By a larger distal deletion reaching almost to the middle of the MluI-HincII fragment, the polypeptide produced for PBP-1b lost the ability to bind penicillin and still retained a low but significant activity for glycan synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acyltransferases↗
PubMed1984

Incidence of the coexistence of left ventricular false tendons and premature ventricular contractions in apparently healthy subjects.

The incidence of the coexistence of left ventricular false tendons and premature ventricular contractions (PVCs) was evaluated prospectively. Over 14 months, left ventricular false tendons were found in 71 (6.4%) of 1117 consecutive patients examined echocardiographically. Two types of false tendons were observed: longitudinal, from the ventricular septum to the posteroapical wall (n = 62), and transverse, between the septum and the lateral wall (n = 9). Among 62 patients with PVCs and no underlying heart disease, false tendons were detected in 35 (56%); 28 had unifocal and seven had bifocal PVCs. Episodes of ventricular tachycardia were documented in one of the 28 patients with unifocal PVCs and in one of the seven patients with bifocal PVCs. These PVCs were poorly controlled by antiarrhythmic drugs but easily suppressed by exercise. Left ventricular false tendons were detected in 36 patients on routine echocardiographic examinations performed in the other 1055 subjects, and 10 of these patients were judged to have no underlying heart disease. PVCs were detected in two (20%) of these 10 patients. Although a definite conclusion that left ventricular false tendons are arrhythmogenic cannot be derived from these results, the unexpectedly high incidence of the coexistence suggests that left ventricular false tendons may be an etiologic factor in the development of PVCs, especially the rate-dependent and medically uncontrollable PVCs seen in apparently healthy individuals.

Adolescent↗
PubMed1984

Effect on exercise tolerance and pharmacokinetics of conventional and sustained release preparations of propranolol in patients with angina pectoris--a double-blind cross-over study.

Ten patients with effort angina were studied in a randomized double-blind cross-over trial in order to investigate the effect of sustained release propranolol (LA) and conventional propranolol (Prop) formulations on exercise tolerance. LA was given once daily and Prop three times daily. Treadmill exercise tests were performed using the Bruce protocol and the plasma propranolol levels were measured. The following results were obtained: LA proved to have an anti-anginal effect similar to Prop. No adverse reactions were observed after administration of either of the drugs. Similar suppressive effect of the heart rate, blood pressure and double product at rest and on exercise was seen after LA and Prop while the exercise capacity was increased. The plasma level of propranolol was higher at 2 hours after Prop than LA administration, but there was no difference between LA and Prop at 4 and 24 hours after administration. The plasma propranolol level at 4 hours after LA correlated with the percent reduction in exercise heart rate and with the percent reduction in the double product. Our study suggested that once-a-day administration of LA could improve patients' compliance and adds another choice to the list of clinically useful beta-blockers for the treatment of angina pectoris on effort.

Aged↗
PubMed1984

Sequential changes of left ventricular function after cineangiography in normal heart and coronary artery disease.

To evaluate the effect of contrast material on left ventricular (LV) function, LV pressure and its first derivative were continuously monitored during and after LV cineangiography with Mikro-tip angiocatheters in 15 normal subjects (Group 1) and patients with coronary artery disease (CAD) without LV asynergy (Group 2, n = 10), with mild asynergy (Group 3, n = 12) and severe asynergy (Group 4, n = 13). In all 4 groups, systolic hypotension, decrease of negative dP/dt, and prolonged time constant of LV pressure fall (T) were observed in 30 seconds after dye injection, and all these parameters returned to the control value in 2 minutes. LV end-diastolic pressure (EDP) began to elevate at one minute, reached its peak at 2 minutes, and stayed elevated for 7 minutes. Although significant decrease in LV systolic pressure was seen, indexes of LV contractility, peak positive dP/dt and (dP/dt)/DP40, showed increase in all groups. No different directional changes of these parameters were observed among 4 groups. The degree of LVEDP elevation was parallel to the diastolic elastic stiffness constant (K) in Group 1 (r = 0.64, (p less than 0.05). It is concluded that systolic hypotension and prolonged relaxation are only transient, and elevation of LVEDP after the contrast material injection seems to be the effect of only acute volume overload.

Adult↗