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Biomedical subjects

K Kaku

Publications and source records attributed to K Kaku.

At least 109 records · Page 6Linked to original sources
PubMed1990

Experimental complete right heart bypass. Proposal of a new model and acute hemodynamic assessment with vasoactive drugs in dogs.

A new model of complete right heart bypass was devised in dogs. All systemic venous blood was directly led to the bilateral pulmonary arteries by end-to-side superior vena cava-right pulmonary anastomosis, diverting the inferior vena caval blood to the superior vena cava with a graft, ligating the inferior vena cava at its end and the pulmonary artery at its trunk, and shunting the coronary venous return from the right-ventricle to the left atrium. Nine consecutive dogs tolerated the procedures, and acute hemodynamic characteristics and responses to vasoactive drugs were observed for 5 hours throughout the following full studies. Cardiac output ranged from 66 to 102 ml/min/kg at a central venous pressure of 15 to 26 mm Hg. Norepinephrine, isoproterenol, and phentolamine were administered with the central venous pressure maintained constant at 18 mm Hg. Isoproterenol and phentolamine increased cardiac output while reducing pulmonary and/or systemic vascular resistance, with a possible concomitant inotropic effect in the former. Norepinephrine was detrimental, causing an increase in both pulmonary and systemic vascular resistance.

Animals↗
PubMed1989

Genetic analysis of obesity-induced diabetes associated with a limited capacity to synthesize insulin in C57BL/KS mice: evidence for polygenic control.

Expression of obesity-induced diabetes associated with the diabetes or db mutation in mice varies in inbred strains. This study utilized a genetic analysis to evaluate the number of genes responsible for the difference in diabetes responses between mice of the susceptible C57BL/KsJ (BL/Ks) and resistant 129/J inbred strains. BL/Ks (db/+) males and 129/J (+/+) females were bred to generate F1 hybrids, and the F1 females (db/+ and +/+, distinguished by progeny testing) were backcrossed to BL/Ks (db/+) males. A total of 252 backcrossed males were obtained, of which 31 were db/db and obese. While the plasma glucose of all the fed backcrossed mice was greater than 22 mmol/l, the expression of diabetes varied considerably, as measured by fasting plasma glucose, fed plasma insulin, and pancreatic insulin and proinsulin mRNA content. That proinsulin mRNA content was a good indicator of diabetes severity and islet dysfunction was seen in the inverse correlation between proinsulin mRNA content and fasting plasma glucose (r = 0.69, p less than 0.001), and a direct correlation between proinsulin mRNA and plasma insulin (r = 0.86, p less than 0.001), and pancreatic insulin content (r = 0.61, p less than 0.01). If a single gene were responsible for severe islet dysfunction, one-half of the backcrossed mice would develop low proinsulin mRNA levels like the BL/Ks parent, and one-half would be resistant to islet destruction. Statistical evaluation (SKUMIX) of the distribution of these parameters in backcrossed mice rejected with a high degree of probability a bimodal distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

A single major gene controls most of the difference in susceptibility to streptozotocin-induced diabetes between C57BL/6J and C3H/HeJ mice.

To assess genetic factors determining sensitivity to streptozotocin-induced diabetes in inbred strains of mice, a genetic analysis of streptozotocin-sensitive C57BL/6J and streptozotocin-resistant C3H/HeJ mice was performed. One week after a single dose of streptozotocin (200 mg/kg body weight), differences in plasma glucose concentration were marked between male mice of the C57BL/6J and C3H/HeJ strains (p less than 0.001). To determine the number of genes responsible for the difference, F1 male progeny of a cross between parental strains were produced, and found to be streptozotocin resistant like C3H/HeJ parents. F1 mice were, therefore, backcrossed with streptozotocin-sensitive C57BL/6J mice (Backcross: F1 female female X C57BL/6J male male). The plasma glucoses of backcrossed male mice (n = 41) following streptozotocin treatment appeared to segregate into two populations, half like the C57BL/6J parent, and half like the F1 parent. Statistical analysis of the data revealed that the data fit a model with two distributions better than one with a single distribution, suggesting a single major gene responsible for the difference in streptozotocin susceptibility. This hypothesis was also supported by the observation that streptozotocin sensitivity in 12 recombinant inbred strains of C57BL/6J and C3H/HeJ mice appeared to segregate into two classes. Resistance to streptozotocin induced diabetes in F1 mice suggested that the expression of this gene is recessive, although X-chromosome linked inheritance could not be excluded. Efforts to map the streptozotocin-sensitivity gene revealed lack of right linkage to several loci including the H-2 locus.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1989

[Influence of ischemic heart disease on early and late mortality after aortic reconstruction for abdominal aortic aneurysm and aortoiliac occlusive disease].

A retrospective study was undertaken to assess the influence of ischemic heart disease (IHD) on the early and late mortality of patients undergoing elective repair of an abdominal aortic aneurysms (AAA) or aortoiliac occlusive disease (AIOD). The patients were divided into IHD and non-IHD groups on routine clinical grounds. Among 157 patients with AAA, postoperative myocardial infarction occurred in 12.8% of the IHD group compared with 0.9% of the non-IHD group (P less than 0.05). The late mortality rate in the IHD group was higher than in the non-IHD group (p less than 0.05), and the mortality rate from myocardial infarction was 30% in the IHD group compared with 13% in the non-IHD group. Among 119 patients with AIOD, clinical evidence of IHD was found in 24 patients and extra-anatomical bypass was performed in 54% of these patients, compared with 35% of the patients in the non-IHD group. There was no occurrence of postoperative myocardial infarction. This study shows that an aggressive diagnostic approach should be taken for patients with AAA who have clinical evidence of IHD and that reevaluation of IHD should be performed in patients with AIOD after aortic reconstructive surgery.

Adult↗
PubMed1989

[Clinical experience of chemotherapy with cefmetazole for severe infections accompanying malignant hematological disorders].

We made an attempt to treat with cefmetazole (CMZ) 25 patients who developed severe infectious diseases while suffering with granulocytopenia associated with the treatment of malignant hematological disorders. 1. Determination of bacteriological efficacy While 20 strains were isolated and identified from 15 patients, no significant bacteria were detected in 9 patients. Isolates obtained were: 5 strains of Enterococcus faecalis, 3 strains of Haemophilus influenzae, 2 strains of Staphylococcus epidermidis, 2 strains of Klebsiella oxytoca, 2 strains of Staphylococcus aureus, and 1 strain each of Neisseria sp., Pseudomonas maltophilia, Enterobacter sp., alpha-Streptococcus, beta-Streptococcus and Gram-positive cocci. Causative organisms were eradicated or markedly in 7 of the 15 patients from whom bacteria were isolated. Clinical findings, including fever, revealed that none of the patients, in whom bacteriological efficacy was determined to be poor, exhibited sufficient clinical response. E. faecalis was isolated from 4 of 6 patients bacteriologically determined to have no response. 2. As for 23 patients, who were found to be evaluable among the 25 patients, 8 (34.8%), 4 (17.4%), 4 (17.4%), and 7 (30.4%) demonstrated excellent, good, fair and poor responses, respectively, showing a 69.6% efficacy rate which indicates a sum of percentages of patients with excellent, good and fair responses. 3. While an efficacy rate of 100% was obtained for 3 patients with number of peripheral neutrophils less than 500/mm3 before the beginning of CMZ administration, only an efficacy rate of 66.7% was obtained for 15 patients with neutrophils more than 500/mm3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Fecal fat excretion rate in patients with Crohn's disease--comparison of a diet containing 50 g/day of fat with elemental diet with an addition of 50 g/day butter fat].

Fecal fat excretion rate was determined by the method of Van de Kamer in 31 patients with Crohn's disease and six healthy controls, when fed by the diet containing 50 g/day of fat. Patients with jejuno-ileitis and those with partial and extensive resection showed a significantly greater excretion rate compared with patients with ileitis and healthy controls, however, there was no significant difference between patients with ileitis and healthy controls. In this study, the fecal excretion rate was less than 10 g/day in non-operated cases. Our results seems to be smaller than those in previous studies from the western countries. Fecal fat excretion rate was determined in 12 patients with non-operated Crohn's disease and six healthy controls, when fed by the additional 50 g/day butter fat during the elemental diet. With ingestion of the additional 50 g/day butter fat during elemental diet, fecal fat excretion rate was significantly increased in the patients with non-operated Crohn's disease than the results of the diet containing 50 g/day fat, but not significantly changed in the healthy controls. This result suggest that determination of fecal fat excretion rate with fed by the additional 50 g/day butter fat during elemental diet is a useful test for detecting a mild fat malabsorption in non-operated Crohn's disease.

Adolescent↗
PubMed1988

Electrophoretic determination of fructose 6-phosphate,2-kinase.

An electrophoretic determination of fructose 6-phosphate,2-kinase activity has been devised. The enzymes partially purified from bovine liver and heart were subjected to polyacrylamide gel electrophoresis and the production of fructose 2,6-bisphosphate, coupled to the activation of potato PPi:phosphofructokinase, was detected as the dark band due to the disappearance of the fluorescence evoked by NADH consumption. The enzyme from bovine heart showed slower electrophoretic mobility than that from bovine liver, strongly suggesting the possibility that they may be distinct enzyme forms. Rat liver enzyme also gave a mobility different from that of both bovine liver and heart enzymes. Our present procedure will provide a new tool for understanding fructose-6-phosphate,2-kinase/fructose 2,6-bisphosphatase system in various tissues.

Animals↗
PubMed1988

Prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in apparently healthy subjects: a prospective study in the general population.

The prevalence of left ventricular false tendons, premature ventricular complexes and their coexistence was evaluated prospectively in 187 healthy company workers aged 21 to 50 (mean 36) years. False tendons were demonstrated echocardiographically in 133 (71%). Eight subjects were withdrawn from the study because of silent mitral valve prolapse. In these 179 healthy subjects, false tendons were detected in 127 (71%) and premature ventricular complexes in 48 (27%). Their coexistence was observed in 40, which showed a significant correlation (p less than 0.05) of false tendons and premature ventricular complexes. In seven of the eight subjects without false tendons, premature ventricular complexes were uniform and infrequent (mean 3 beats/24 h). In the 40 subjects with false tendons, premature ventricular complexes were uniform in 29, multiform in 6 and repetitive in 5, and the mean frequency was 96 beats/24 h. Correlation of premature ventricular complexes with the type of false tendons showed that premature ventricular complexes were significantly associated with thick (greater than or equal to 2 mm) and longitudinal tendons (p less than 0.005). Although it is not certain that left ventricular false tendons are arrhythmogenic, the prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in the general population, and the special relation between the frequency and the form of premature ventricular complexes and the type of false tendons, suggests that false tendons may play an etiologic role in the genesis of premature ventricular complexes in apparently healthy subjects.

Adult↗
PubMed1988

Depressed myocardial contractility in mitral stenosis--an analysis by force-length and stress-shortening relationships.

To determine whether low ejection fraction (EF) in mitral stenosis (MS) is the result of depressed contractility or is mediated by other factors, left ventricular (LV) function was analyzed by force-length and stress-shortening relationships. Thirty patients without heart disease served as normal controls (Group 1). Forty-three patients with MS were divided into 2 subgroups: Group 2 (n = 19) had EF within one standard deviation of the mean of Group 1, and Group 3 (n = 24) had EF below it. Normal EF (Group 2) was associated with low preload (end-diastolic stress) and low afterload (end-systolic stress), and preload and afterload were in the normal range in patients with low EF (Group 3). A significant negative correlation was observed in the whole group of patients with MS between EF and end-systolic stress (Y = -0.14X + 72.8, r = -0.61, p less than 0.001), and a positive correlation between end-systolic stress and volume (Y = 1.39X + 65.4, r = 0.45, p less than 0.01). These observations suggest that systolic shortening and end-systolic volume of the left ventricle are in part governed by afterload in this disease. It is concluded that low EF of MS is not mediated by reduced preload or inappropriately elevated afterload, and contractility of the ventricle is mildly depressed in MS.

Adult↗
PubMed1988

Genetic analysis of glucose tolerance in inbred mouse strains. Evidence for polygenic control.

To determine genetic factors involved in diabetes susceptibility in inbred strains of mice, we initially evaluated differences in fed plasma glucose and insulin concentrations among six strains (AKR/J, C3H/HeJ, C57BL/6J, C57L/J, DBA/2J, and SWR/J). There was considerable variation in fed plasma glucose concentration, with C3H/HeJ mice the most glucose tolerant (174 +/- 7 mg/dl) and C57BL/6J mice the least glucose tolerant (252 +/- 7 mg/dl, P less than .0001 vs. C3H/HeJ mice). Glycosylated hemoglobin of C57BL/6J mice (4.0 +/- 0.06%) was also higher than that of C3H/HeJ mice (3.52 +/- 0.06%, P less than .0001). The fed plasma insulin concentration did not differ between these two strains. Glucose tolerance was further evaluated in overnight-fasted C3H/HeJ and C57BL/6J mice by an intraperitoneal glucose tolerance test (IPGTT). Although fasting plasma glucose did not differ, the most remarkable difference in plasma glucose during IPGTT between C57BL/6J and C3H/HeJ mice was noted at 30 min (489 +/- 29 vs. 227 +/- 20 mg/dl, P less than .001). To determine the number of genes involved in the phenotypic difference in glucose tolerance, C57BL/6J males were crossed with C3H/HeJ females (F1, C3H/HeJ X C57BL/6J), and the F1 hybrid females were backcrossed with C57BL/6J males (backcrossed, F1 X C57BL/6J). Plasma glucose after 30 min on IPGTT was 219 +/- 8 (n = 21), 456 +/- 18 (n = 23), and 292 +/- 13 (n = 23) mg/dl for C3H/HeJ, C57BL/6J, and F1 mice, respectively (P less than .001 for all comparisons).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

Optimal timing for valve replacement in chronic aortic regurgitation: analysis based on the myocardial contractility and postoperative prognosis.

Left ventricular (LV) function was evaluated considering force-velocity and stress-shortening relationships in 14 asymptomatic (Group 1), 18 symptomatic patients (Group 2), and 53 normal subjects (Group 3) to determine the optimal time for valve replacement in patients with chronic aortic regurgitation (AR). Valve replacement was recommended for all Group 2 patients and for one patient in Group 1, who had sustained ventricular tachycardia. There was one operative death and five deaths remote from surgery; one patient in Group 1 died suddenly of undetermined cause, and four patients in Group 2 died of congestive heart failure (CHF). The LV end-systolic volume index (ESVI) was greater than 100 ml/m2 in the five patients whose death was unrelated to surgery (remote deaths). ESVI was less than 50 ml/m2 in all but two patients in Group 1, and more than 40 ml/m2 in all cases in Group 2. The index of preload, end-diastolic stress (sigma ed), was increased in Groups 1 and 2 as compared with Group 3. A significant positive correlation was observed between end-systolic stress (sigma es) and ESVI (r = 0.71, p less than 0.001) in patients with AR, and this linear line was not as steep as that of Group 3. Afterload (sigma es) and ejection fraction (EF) in Group 1 were within normal range, afterload was normal but EF was reduced in mildly symptomatic patients in Group 2, and severely symptomatic patients had markedly reduced EF and elevated afterload. There was a close correlation between ESVI and end-diastolic volume index (EDVI), and this was expressed as an exponential curve (Y = 21.69e0.006x, r = 0.88, p less than 0.001). This indicates that the rate of shortening of the muscle fiber deteriorates exponentially with enlargement of the ventricle. These observations suggest that in AR patients: 1) afterload and contractility of the ventricle remain normal in the majority of asymptomatic patients by means of compensatory hypertrophy and preload elevation (preload reserve), 2) deterioration of contractility seems to be the factor initiating CHF, and 3) progression of CHF is due to further deterioration of contractility in addition to elevation of afterload (afterload mismatch). It is concluded that careful observations are necessary when ESVI exceeds 50 ml/m2 in asymptomatic patients. Valve replacement is recommended when such patients develop symptoms of CHF, or either when EF falls to less than 50% or ESVI exceeds 100 ml/m2, even if patients remain asymptomatic.

Aortic Valve↗
PubMed1987

Evaluation of left ventricular contractility in hypertrophic cardiomyopathy from end-systolic pressure-volume relation.

To evaluate myocardial contractility in hypertrophic cardiomyopathy (HC), we obtained the end-systolic pressure-volume relation (ESPVR) and the end-systolic stress-volume relation (ESSVR) by changing loading conditions with Angiotensin II. The left ventricular (LV) stress-shortening relation was also analyzed in order to assess myocardial contractility. LV end-systolic pressure, end-systolic volume, end-systolic stress, and ejection fraction were obtained at rest and during Angiotensin II infusion with simultaneous recordings of pressure and volume in 9 patients with hypertrophic cardiomyopathy and 9 normal subjects (N). The slopes of ESPVR, Emax, showed no significant difference (HC: 3.1 +/- 2.3 vs N: 2.6 +/- 1.4 mmHg/ml, ns). The slopes of ESSVR were statistically similar (HC: 5.2 +/- 2.1 vs N: 6.0 +/- 2.8 g/cm2 ml, ns). The slopes of end-systolic stress-ejection fraction relation were also in the same range in both groups (HC: -0.09 +/- 0.05 vs N: -0.10 +/- 0.05, ns). From these two different analyses of LV contractility, we conclude that myocardial contractility is normal in hypertrophic cardiomyopathy and not supernormal, at both chamber and muscle levels. Considering the increased muscle mass in hypertrophic cardiomyopathy (HC: 134 +/- 46 vs N: 74 +/- 19 g/m2, p less than 0.01), the presence of increased numbers of contractile units does not result in enhanced overall chamber contractility.

Adult↗
PubMed1987

[Relationship between clinical efficiency of cefoperazone and the value of area under the time concentration curve in infectious diseases].

Clinical efficiency and side effects of cefoperazone (CPZ) against 40 infectious diseases in the field of internal medicine were studied. In addition, relationship between clinical efficiency and the value of area under the time concentration curve (AUC) was evaluated. It was possible to evaluate clinical responses in 36 cases of 40 infections; Responses were excellent in 15, good in 16, fair in 3 and poor in 2. An overall efficacy rate was 86.1%. A high dose of CPZ (2 g X 2/day) produced a higher efficacy rate than a low dose of the drug (1 g X 2/day) [95.8% (23/24 cases) vs. 66.7% (8/12 cases)] but the difference was not statistically significant. It was possible to evaluate bacteriological efficacy in 32 cases. Bacteria were eradicated in 29 (90.6%) and decreased in 3. The value of AUC in the high dose group was significantly higher than that in the low dose group. Values of AUC in cases of excellent or good clinical responses tended to be higher than values in cases of fair or poor responses. Side effects were noted in 4 cases, but they were not serious and improvements were observed without withdrawal of the drug except 1 case.

Adolescent↗