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Biomedical subjects

J Fukushige

Publications and source records attributed to J Fukushige.

At least 37 records · Page 2Linked to original sources

The mechanism of lack of hypocholesterolemic effects of pravastatin sodium, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, in rats.

In order to clarify the reason why pravastatin, a 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor, did not show hypocholesterolemic effects in rats, the changes of various parameters affecting the serum cholesterol levels by pravastatin were determined in rats and rabbits, as a comparison. In rabbits, pravastatin administration at 50 mg/kg for 14 days decreased serum and liver cholesterol by 40% and 8%, respectively. The hepatic LDL receptor activity was increased 1.7-fold, and VLDL cholesterol secretion was decreased. Cholesterol 7 alpha-hydroxylase activity was not changed. In contrast, in rats, serum cholesterol was increased by 14% at 50 mg/kg and 27% at 250 mg/kg for 7 days, respectively. At 250 mg/kg, liver cholesterol was significantly increased by 11%. Under these conditions, neither the hepatic LDL receptor activity nor cholesterol 7 alpha-hydroxylase was changed, and VLDL cholesterol secretion was increased. At 250 mg/kg, net cholesterol synthesis in rat liver was increased after 7 days of consecutive administration. These results imply that in rats, stimulated net cholesterol synthesis caused the increase of liver cholesterol followed by the increase of VLDL cholesterol secretion, and resulted in the raise of plasma cholesterol. Although hepatic HMG-CoA reductase was induced almost the same fold in both animals at 50 mg/kg, the induced HMG-CoA reductase activity in rats might overcome the inhibitory capability of pravastatin, resulting in an increase of net cholesterol synthesis, but not in rabbits. This over response to pravastatin in rats might cause the lack of hypocholesterolemic effects of this drug.

Animals↗

Patent ductus venosus associated with a hyperintense globus pallidum on T1-weighted magnetic resonance imaging and pulmonary hypertension.

UNLABELLED: We report the case of a 13-year-old Japanese boy with a patent ductus venosus. He experienced mild disorientation and hallucination at age 8 years. Hyperammonaemia was discovered at age 12 years. Brain MRI demonstrated multiple intracranial hyperintense lesions, mainly in the globus pallidum, which suggested portosystemic encephalopathy. Patent ductus venosus was demonstrated by abdominal ultrasonography and angiography. Cardiopulmonary investigation revealed pulmonary hypertension. An intracranial hyperintense lesion observed on T1-weighted MRI may be an initial clue for discovering a patent ductus venosus in asymptomatic patients. CONCLUSION: When patent ductus venosus is disclosed, pulmonary hypertension should be sought, as in cases with other portosystemic shunts.

Adolescent↗

Histiocytic haemophagocytosis in a patient with Kawasaki disease: changes in the hypercytokinaemic state.

UNLABELLED: A 32-month-old Japanese boy exhibited haemophagocytic syndrome (HPS) during the recurrent course of Kawasaki disease. Despite repeated gamma-globulin therapy, he developed cytopenia with marked hepatomegaly and evidence of histiocytic haemophagocytosis in the bone marrow. Serum levels of interferon-gamma and tumour necrosis factor, but not of interleukin-1 beta, increased in parallel with his symptoms. No confirmation was obtained of the association of toxic reactions to the used drugs. No coronary lesions remained as sequelae. CONCLUSION: Cytopenia in Kawasaki disease could herald HPS, and the hypercytokinaemia involved in the two febrile syndromes might be of distinct nature.

Child, Preschool↗

Occlusion of the right coronary artery as sequelae of Kawasaki disease: the clinical features of 9 cases.

Among the 302 children with Kawasaki disease (KD) who were evaluated by angiography from 1973 through 1992, 9 (3.0%) had either an occlusion (OC) or segmental stenosis (SS) of the right coronary artery. The interval from the onset of KD to the recognition of OC or SS ranged from 0.5 to 7.7 years (median 4.0 years). Left coronary arterial lesions were also present in 8 of 9 patients. In spite of severe sequelae, children or young adolescents with cardiovascular system-related symptoms were unexpectedly rare. Asymptomatic patients, however, are also at risk of developing myocardial infarction since they have been shown to have a high rate of abnormalities on myocardial scintigraphy. A close observation and careful follow-up are thus considered to be indispensable.

Adolescent↗

Incidence of structural cardiac disorders in neonates: an evaluation by color Doppler echocardiography and the results of a 1-year follow-up.

Non-biased 502 consecutive neonates were examined by sectorial and color Doppler flow imaging at a mean age of 1.0 day (SD 0.4). Patent foramen ovale was present in 266 (53%) and transient patent ductus arteriosus in 104 (21%). Cardiac disorders were recognized in 19 (3.8%); ventricular septal defect (VSD) in 10; atrial septal defect (ASD) in 4; pulmonary stenosis in 2; aortic stenosis, endocardial cushion defect and tricuspid regurgitation in 1 each. With a spontaneous closure of 8 VSDs and 4 ASDs during the first 12 months, the incidences of cardiac malformation were, consequently, 3.2% at 1 month, 1.4% at 6 months and 1.0% at 12 months.

Birth Weight↗

Reduction of serum cholesterol levels alters lesional composition of atherosclerotic plaques. Effect of pravastatin sodium on atherosclerosis in mature WHHL rabbits.

We examined whether serum cholesterol reduction alters the lesional composition of atherosclerotic plaques. To reduce serum cholesterol levels, we gave pravastatin sodium, a 3-hydroxy-3-methylglutaryl Coenzyme A reductase inhibitor, to mature Watanabe heritable hyperlipidemic rabbits, an LDL receptor-deficient animal model, for 48 weeks. Atherosclerotic lesions were immunohistochemically and conventionally stained and each lesional component area was measured by a color image analyzer. Compared with those of a placebo group, serum LDL cholesterol levels were reduced by 22% (P<.05). Data for atherosclerosis indicated a significant decrease in percent of surface lesion area (26% reduction) and in intimal thickening (30% reduction) in the abdominal aorta, as well as in coronary stenosis (29% reduction). Data for lesional composition indicated a significant decrease in the percent area of macrophage plus extracellular lipid deposits in aortic lesions (32% reduction) and coronary lesions (45% reduction). A significant increase was observed in the percent area of collagen in aortic lesions and in the percent area of smooth muscle cells in coronary lesions. The plaques seemed to become stable lesions as a result of pravastatin treatment. In conclusion, a long-term reduction of serum LDL cholesterol reduced lipid-related lesional components, in addition to suppressing the progression of established atherosclerosis.

Animals↗

Blood pressure levels in school-age Japanese children: the Hisayama Study.

Blood pressure (BP) measurements were obtained on a total of 6325 children (3294 boys and 3031 girls), aged 6-14 years, in Hisayama, Japan. All BPs were recorded in a sitting position by trained observers in a standardised manner. Standard mercury sphygmomanometers were used with commercially available cuffs, selected according to the arm circumference. Cuff size no. 3 (bladder width 9 cm, length 23 cm) was the one most commonly selected in 84% of elementary schoolers aged 6-11 years and in 35% of junior high schoolers aged 12-14 years. Mean systolic BPs (SBPs) increased from 89 mm Hg at age 6 years to 108 mm Hg at 14 years (a 21% increase) for boys and from 88 mm Hg to 102 mm Hg (a 16% increase) for girls. Diastolic BP (DBPs, Korotkoff phase IV, KIV) increased from ages 6 to 14 years to the same degree, from 58 mm Hg to 72 mm Hg (a 24% increase) for boys and from 58 mm Hg to 70 mm Hg (a 21% increase) for girls. The increase in DBP (Korotkoff phase V, KV) was greater, from 48 mm Hg to 63 mm Hg (a 30% increase) for boys and from 48 mm Hg to 61 mm Hg (a 28% increase) for girls. The increase in mean SBP for adolescent boys was greater compared with that of girls; however, separation of age-specific values by sex was not observed for mean DBP (KIV) and DBP (KV). The cross-sectional relation between age and mean SBP levels was not linear.

Adolescent↗

Influence of upright activity on plasma renin activity and aldosterone concentration in children.

Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in 156 healthy infants and children under basal conditions of normal diet and recumbency. PRA and PAC were also evaluated during and after stimulation of the renin-angiotension-aldosterone system by postural change. Basal values of PRA significantly declined with increasing age. Postural change by standing up resulted in an increase of PRA and PAC in all age groups. The increment of PRA but not of PAC was greater in older than in younger children. Neither the basal nor the stimulated levels of PRA and PAC were influenced by sex, body weight, body surface area, serum sodium, serum potassium, creatinine, and 24-h urine secretion of sodium and potassium. Both PRA and PAC returned to the basal levels within 60 min after resuming recumbent posture.

Adolescent↗

Incidence and clinical features of incomplete Kawasaki disease.

During the nine-year period from 1983 to 1991, a total of 242 patients (142 males and 100 females) presenting with Kawasaki disease were seen at one hospital. Among them, 25 (10%) patients demonstrated incomplete Kawasaki disease and 17 of these 25 (68%) lacked two of the six principal symptoms of Kawasaki disease, with the most frequently missing symptoms being cervical lymphadenopathy and polymorphous exanthema. The typical laboratory features of Kawasaki disease, such as elevated erythrocyte sedimentation rate, leukocytosis, anemia, positive C-reactive protein and thrombocytosis were also seen in the incomplete cases. None of the 25 patients underwent iv gamma-globulin therapy while in 1 (4%), transient dilatation of the coronary artery was recognized. Incomplete Kawasaki disease may therefore be characterized by a less frequent association of rash, cervical lymphadenopathy and coronary involvement.

Child, Preschool↗

Discordance between thallium-201 scintigraphy and coronary angiography in patients with Kawasaki disease: myocardial ischemia with normal coronary angiogram.

To assess the usefulness of radionuclide tests in detecting coronary occlusive lesions in children with Kawasaki disease, we compared the results of stress thallium-201 myocardial single photon emission computed tomography with dipyridamole infusion and coronary angiography in 34 patients (19 males and 15 females). Perfusion defects on the stress image only were categorized as transient and were attributed to coronary vascular disease in the presence of redistribution on the delayed image. Others were classified as persistent, due to myocardial damage. Five of the seven children (71%) with severe stenosis on coronary angiography showed persistent and/or transient perfusion defects. However, six of the 11 children (55%) with aneurysms but no obvious stenosis, and four of the 16 children (25%) with normal angiography, showed persistent and/or transient defects. After analyzing 20 individual segments of perfusion defects in the 15 children, six segments (30%) were attributed to the stenosis of supplying coronary arteries, six segments (30%) were related to the coronary aneurysms, and eight segments (40%) were unrelated to any abnormalities on angiography. Thus, significant discordance between the radionuclide and angiographic studies was demonstrated. These results suggest that coronary lesions, as conventionally defined by angiography and supplemented by echocardiography, may not completely identify all Kawasaki patients who may develop myocardial ischemia in the future or who had ischemia in the past.

Adolescent↗

Effects of HMG-CoA reductase inhibitors on skeletal muscles of rabbits.

This study was undertaken to evaluate the potential of HMG-CoA reductase inhibitors, pravastatin sodium (hereafter abbreviated to pravastatin) and simvastatin, for induction of myopathy and influence on the ubiquinone content of skeletal and cardiac muscles and other tissues in the rabbit. Both drugs were administered orally to New Zealand White rabbits (n = 5) at the dose of 50 mg/kg per day for 14 days. Serum cholesterol levels in the pravastatin- and simvastatin-treated groups were reduced significantly by 47% an 58% on day 14 (P < 0.05), respectively, as compared with the control group, but the difference between the two treatment groups was not significant. In animals of the simvastatin-treated group, abnormal elevations of creatine kinase (CK) and lactate dehydrogenase (LDH) levels were observed, in association with severe lesions in skeletal muscles, but not cardiac muscle. The ubiquinone content in skeletal muscle in this treatment group was not affected, even in the muscles that had severe lesions, whereas that in liver and cardiac muscle was significantly reduced compared with the control group. The results suggest that there is no direct correlation between myopathy and the decrease of ubiquinone content in skeletal muscles. In contrast, the animals in the pravastatin-treated group did not show any changes in CK and LDH levels, ubiquinone content in liver and muscles, or in histopathological features of muscle fibers. The difference between the adverse effects seen with the two drugs could be attributed to physicochemical properties: simvastatin permeates the plasma membrane because of its hydrophobic nature, whereas pravastatin does not, because it is hydrophilic.

Administration, Oral↗

Anomalous origin of the left coronary artery from the right pulmonary artery: report of a case.

A 1-year-old boy was referred to our hospital for further investigation of mitral regurgitation. Color-Doppler echocardiography revealed the site of the anomalous origin of the left coronary artery which was confirmed by a cineangiographic study. This case is interesting for several reasons: the first is that the anomalous left coronary artery originated from the right pulmonary artery; the second is that two-dimensional echocardiographic findings can be misleading, i.e., a vessel-like structure which seemed to be the left coronary artery arising normally from the aorta was visualized; and the last is that a two-dimensional color-Doppler echocardiogram was useful in the diagnosis of the anomalous origin of the left coronary artery. The patient underwent implantation of the anomalous left coronary artery as well as Kay's plasty of the mitral valve, and has been doing well since then.

Coronary Vessel Anomalies↗

Effect of increase in heart rate on interatrial shunt in atrial septal defect.

The effect of increases in heart rate by atrial pacing was investigated in 20 children [mean 9 +/- 4 (SD) years] with atrial septal defect. Systemic blood flow increased by 13 +/- 10 and 27 +/- 22% with a 25 and 50% increase in heart rate, respectively. Pulmonary blood flow, however, remained unaltered. Thus, rapid pacing decreased the pulmonary to systemic blood flow ratio significantly (-15 +/- 10 and -22 +/- 13%, respectively). This hemodynamic alteration was attributed to the difference in diastolic distensibility (compliance) between the left and right ventricles, and the ratio of right ventricular to left ventricular compliance (defined by dV/dP) near the end-diastolic pressure was estimated to be 6.5 +/- 4.2. It is suspected that the increase in heart rate may contribute to the lowering of pulmonary to systemic flow ratio during exercise in children with atrial septal defect.

Adolescent↗

Effects of pravastatin sodium alone and in combination with cholestyramine on hepatic, intestinal and adrenal low density lipoprotein receptors in homozygous Watanabe heritable hyperlipidemic rabbits.

Pravastatin sodium (pravastatin), a tissue-selective inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, was administered alone (50 mg/kg) or in combination with cholestyramine, a bile acid sequestrant resin, at the level of 2% in the diet to homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits for 4 weeks. The low density lipoprotein (LDL)-cholesterol levels were reduced by 29% and 56% with pravastatin alone and the combination treatment, respectively. Hepatic LDL receptor activity was increased by 11.2- and 13.9-fold with pravastatin alone and the combination treatment, respectively. The LDL receptor activity in the untreated homozygous WHHL rabbits was only 2.5% of that in the normal rabbits. mRNA for the LDL receptor in the liver was also increased by 2.1- and 3.4-fold with pravastatin alone and the combination treatment, respectively. On the other hand, mRNA for the LDL receptor in the adrenal gland was not affected by pravastatin and the combination treatment, whereas the mRNA in the intestine was increased in both groups. These results suggest the following: 1) the induction of hepatic LDL receptor activity by the treatment of pravastatin alone or in combination with cholestyramine is the main cause of the reduction of serum cholesterol levels by these treatments even in LDL receptor-deficient animals. 2) The induction of the mRNA for the LDL receptor in the liver and intestine, but not that in the adrenal gland, might be a reflection of the tissue-selective inhibition of cholesterol synthesis by pravastatin.

Adrenal Glands↗

The effects of R-75,317 on antiglomerular basement membrane glomerulonephritis in rats.

Platelet-activating factor (PAF) is a potent inflammatory mediator which is released by various inflammatory cells and produced by certain tissues, including the kidney. PAF has been shown to increase glomerular permeability to protein and to decrease glomerular filtration rate (GFR) by contracting mesangium. On the basis of these observations, it has been suspected that PAF may play a role as mediator of glomerular damage in glomerular nephritis. To examine this possibility, we studied the effects of a specific PAF antagonist, R-75,317, on the development of an experimental model of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. Glomerulonephritis was initiated by injecting rabbit anti-rat GBM serum into rats. Proteinuria gradually developed after serum injection, plateaued at week 2, and remained at the high level of week 2 throughout the experimental period (6 wk). Chronic treatment with R-75,317 (10 mg/kg/day i.p.) tended to delay the onset of proteinuria and significantly accelerated the recovery phase. Creatinine clearance (Ccr) fell to 40% at week 3. R-75,317 treatment completely prevented this decline of Ccr. Histological changes in this model (glomerular hypertrophy, proliferation of mesangial matrix and interstitial fibrosis) were also ameliorated by the R-75,317 treatment. The results suggest that PAF may play a role in the development of glomerulonephritis and that PAF antagonists could be used in the treatment of human renal disease.

Acetylglucosaminidase↗