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Biomedical subjects

F Ishibashi

Publications and source records attributed to F Ishibashi.

At least 19 recordsLinked to original sources
PubMed1999

Outcome of target sites escaping high-grade (>70%) restenosis after percutaneous transluminal coronary angioplasty.

This study examined the fate of target sites that escaped high-grade restenosis (> or = 70% diameter narrowing) after percutaneous transluminal coronary angioplasty. Although favorable long-term prognosis after successful percutaneous transluminal coronary angioplasty is well documented, little is known about the stability of target sites. Long-term follow-up (mean 6.5 years, range 1.0 to 12.0) was performed in 693 patients with 948 narrowings (stenosis <70% in diameter at follow-up coronary angiography). Among them, 249 patients (36%) with 303 target sites received late follow-up coronary angiography. The relation of target sites to the culprit lesions for coronary events or newly developed angina was angiographically reviewed and progression/regression was also examined, focusing on the target sites. Regression was observed in 16 of 255 target sites in subjects with <50% stenosis and in 21 of 48 sites in the group with midgrade stenosis of 50% to 69% luminal narrowing (16 of 255, 6.3% vs 21 of 48, 43.8%, p <0.001). Progression was observed in 33 and 4 sites (33 of 255, 12.9% vs 4 of 48, 8.3%; p = NS) in each group, respectively. The rest remained within the same range of stenosis. Culprit lesions for 2 acute myocardial infarctions, 7 unstable anginas, and 17 newly developed anginas were related to the original target sites. Three lesions developed in the midgrade stenosis group. Those 26 lesions were a component of 8.6% of 303 angiographically confirmed sites and 2.7% of total target sites. Target sites that escape high-grade restenosis frequently regress and become stable plaques and rarely trigger coronary events.

Aged↗
PubMed1999

Contribution of human hepatic cytochrome P450s and steroidogenic CYP17 to the N-demethylation of aminopyrine.

1. Aminopyrine N-demethylase activity was determined for 11 forms of human hepatic cytochrome P450s (P450s) expressed in yeast Saccharomyces cerevisiae and for human steroidogenic CYP17 expressed in Escherichia coli. 2. Among the hepatic P450s, the N-demethylation of aminopyrine was catalysed most efficiently by CYP2C19, followed by CYP2C8, 2D6, 2C18 and 1A2, whereas the activity with CYP2E1 was negligible. The kinetics of the N-demethylation process by CYP1A2, 2C8, 2C19 and 2D6 were studied by fitting to Michaelis-Menten kinetics by Lineweaver-Burk plots. CYP2C19 exhibited the highest affinity and a high capacity for the aminopyrine N-demethylation. CYP2C8 showed the highest Vmax, followed by CYP2C19, 2D6 and 1A2, whereas the Km for CYP2C8, 2D6 and 1A2 were 10-17 times higher than that for CYP2C19. Accordingly, the Vmax/Km for CYP2C19 was more than nine times higher than that of other P450s. 3. Human steroidogenic CYP17 also catalysed aminopyrine N-demethylation and the activity was comparable with that for CYP3A4 which is a dominant P450 in human liver. The activity was increased 1.5-fold by the addition of cytochrome b5, whereas the activity was not affected by the addition of Mg2+. 4. These results suggest that several human hepatic P450s, especially CYP2C19, and steroidogenic CYP17 exhibit aminopyrine N-demethylase activity.

Aminopyrine↗
PubMed1999

[Statistical evaluation of chronic granulomatous disease in Japan and basic studies for gene therapy for CGD patients].

Chronic granulomatous disease (CGD) is an inherited immune deficiency caused by mutations in any of the following four phox genes encoding subunits of the superoxide generating phagocyte NADPH oxidase. It consists of membranous cytochrome b558 composed of gp91-phox and p22-phox, and four cytosolic components, p47-phox, p67-phox, rac p21 and p40-phox, which translocate to the membrane upon activation. In our group study, more than 220 CGD patients has been enrolled. The incidence of CGD patients was estimated as 1 out of 250,000 births. The expected life span of the CGD patients is 25 to 30 years old by the Kaplan Meier analysis. Comparing with the ratio of CGD subtype in US and Europe, that with p47-phox deficiency is lower (less than 10% vs. 23%) and that of gp91-phox deficiency is higher (more than 75% vs. 60%). Prophylactic administration of ST antibiotics and IFN-gamma and bone marrow transplantation have been successfully employed in our therapeutic strategy. However, it is necessary to develop the gene therapy technology for CGD patients as more promising treatment. In the current study we constructed two retrovirus vectors; MFGS-gp91/293 SPA which contains only the therapeutic gp91-phox gene, a bicistronic retrovims pHa-MDR-IRES-gp91/PA317 which carries a multi drug resistant gene (MDR1) and the gp91-phox gene connected with an internal ribosome entry site (IRES). We demonstrate high efficiency transduction of gp91-phox to CGD EB virus established cell line with high levels of functional correction of the oxidase by MFGS-gp91 and by pHa-MDR-IRES-gp91, respectively. We also demonstrate sufficient transduction of gp91-phox to CD34+ haematopoietic stem cell from the patients with gp91-phox deficiency by MFGS-gp91/293 SPA. Our current studies suggest that the combination of the 293-SPA packaging system and the bicistronic retrovirus system inserted MDR1 gene make our CGD gene therapy more feasible for clinical application.

Adolescent↗
PubMed1998

Evidence that immature rat liver is capable of participating in steroidogenesis by expressing 17alpha-hydroxylase/17,20-lyase P450c17.

Steroid hydroxylase cytochrome P450c17 has been previously purified from microsomal fractions of immature rat livers. In this study, we investigated the expression of P450c17 in rat livers to understand a role of steroidogenesis in the extrasteroidogenic tissue. Upon immunoblot analysis utilizing liver microsomes from rats, P450c17 was detected in 1 and 3 week old rats but not in adult rats. Data from immunohistochemical studies also showed a similar age-dependent expression of P450c17 and indicated that P450c17 detected in immature rat livers is localized in cells surrounding interlobular veins. This age-dependent expression of P450c17 in rat livers was observed in both sexes. Upon enzymatic analysis utilizing microsomal fractions from livers, levels of 17alpha-hydroxylase and 17,20-lyase activity for pregnenolone and progesterone increased by 3 weeks and dramatically reduced at 7 weeks, which is consistent with the expression level of P450c17. These data clearly indicate that P450c17 is expressed in immature rat liver to produce 17alpha-hydroxysteroids and C19-steroids. Based upon immunoblot analysis, the expression level of P450c17 in immature rat livers was approximately one third of that in testis. Compared expression level of P450c17 and total volume of organs between liver and testis, the total amount of steroid metabolites produced by liver P450c17 could be greater than that produced by gonadal P450c17. Because of the absence of P450c17 in rat adrenal glands, rat liver could be the major site for producing 17alpha-hydroxysteroids and C19-steroids in this particular period of life. Although physiological products formed by P450c17 in liver and their roles remain to be elucidated, this study suggests a large capacity of prepubertal rat liver for participating the production of steroid hormones and a putative importance of 17alpha-hydroxysteroids and C19-steroids, such as cortisol and androstendione, which are generally believed to be minor components of steroid hormones in rodents.

Animals↗
PubMed1998

Contribution of human hepatic cytochrome P450 isoforms to regioselective hydroxylation of steroid hormones.

1. Hydroxylation activities toward steroid hormones were determined for eleven forms of human hepatic cytochrome P450s expressed in yeast Saccharomyces cerevisiae cells. Microsomes were prepared from the yeast cells and assayed for their regioselectivity of hydroxylation toward progesterone, pregnenolone, dehydroepiandrosterone (DHEA) and oestrone. 2. 6 beta-Hydroxylation of progesterone was catalysed most efficiently by CYP3A4, followed by CYP2D6. CYP3A4 showed the highest progesterone 16 alpha-hydroxylation activity, followed by CYP1A1 and CYP2D6. 16 alpha-Hydroxylation of pregnenolone was catalysed efficiently by CYP1A1 and CYP3A4. Only CYP3A4 exhibited 16 alpha-hydroxylase activities toward DHEA and oestrone. 3. Addition of nifedipine, a typical substrate of CYP3A4, inhibited the 6 beta- and 16 alpha-hydroxylation of progesterone by CYP3A4. 4. These results suggest that CYP3A4 and CYP1A1 are responsible for the hydroxylation of these endogenous steroids, as well as xenobiotics, in human liver.

Aryl Hydrocarbon Hydroxylases↗
PubMed1997

[A case of mitral valve prolapse diagnosed by transesophageal echocardiography during emergency laparotomy].

We described a case of severe mitral valve prolapse diagnosed and successfully managed with transesophageal echocardiography (TEE) during emergency laparotomy for obstructive ileus. As the nature of the surgical procedure and the condition of the patient did not allow us to spend time to perform full cardiac examination preoperatively, we decided to use intraoperative TEE for the determination of cardiac pathology and for the monitoring of ventricular function. We discussed the indication of TEE during noncardiac surgery in patients having cardiac complications. The anesthesiologists should be able to utilize TEE to make correct decision in the hemodynamic management, especially when the preoperative cardiac evaluation is insufficient or lacking.

Aged↗
PubMed1996

Microalbuminuria in NIDDM is caused by increased excretion of unmodified albumin.

After an intravenous infusion Of L-arginine to inhibit tubular reabsorption of albumin, glomerular clearance, renal clearance, and tubular reabsorption of unmodified albumin (UMA) and glycated albumin (GA) were determined in 72 patients with NIDDM without (NIDDM-I; n = 47) or with microalbuminuria (NIDDM-II; n = 25) and in 24 healthy control subjects. Samples of serum albumin and dialyzed urine obtained 60 min before and during L-arginine infusion were applied to an affinity column to separate GA from UMA, and their albumin contents were assayed. The serum level of GA in NIDDM patients was higher than that in control subjects (P < 0.0001). Both UMA and GA were excreted in excess in NIDDM-II as compared with the other two groups (P < 0.0001), and UMA comprised 80% of total albumin excretion. In NIDDM-II, the glomerular clearance of UMA (2.5 +/- 0.16 > NIDDM-I [1.8 +/- 0.1] > control subjects [1.3 +/- 0.1 microliter/min], P < 0.001) and of GA (1.7 +/- 0.13 > NIDDM-I = control subjects [1.1 +/- 0.1 microliter/min], P < 0.001) were enhanced, as compared with the other two groups. Renal clearance of UMA (1.3 +/- 0.13 microliter/min) and GA (0.89 +/- 0.09 microliter/min) in NIDDM-II was greater than that in control subjects (0.27 +/- 0.03, 0.19 +/- 0.02 microliter/min) or in NIDDM-I (0.30 +/- 0.03, 0.11 +/- 0.01 microliter/min). Tubular reabsorption of UMA, as assessed by the difference between glomerular and renal clearances of albumin, in NIDDM-II (1.1 +/- 0.1 microliter/min) was less than in NIDDM-I (1.50 +/- 0.09 microliter/min), and that of GA in NIDDM-II was lower than that in the other two groups, despite exaggerated glomerular clearance of GA and UMA in NIDDM-II. In summary, microalbuminuria in NIDDM is caused by increased excretion of UMA resulting from the decompensated ability of tubular reabsorption, which is exceeded by increased glomerular clearance of UMA.

Adult↗
PubMed1996

Cytochrome P450s of isolated rat hepatocytes in spheroid and monolayer cultures.

The maintenance of cytochrome P450s (P450s) and NADPH-cytochrome P450 reductase (P450 reductase) in the monolayer and spheroid cultures of hepatocytes from male rats was examined. The content of total P450 in monolayer culture decreased to almost none after 144 hr, whereas the level in spheroid culture remained within 6-13% of initial values during an incubation period of 144-192 hr. P450 2C11, a major P450 in male rat, in monolayer cells rapidly decreased in 144 hr, while the level in spheroid cells after 144 hr and 192 hr maintained 25% and 15%, respectively, of initial level. On the other hand, P450 2A1 and P450 2E1 in both monolayer and spheroid cells rapidly decreased. P450 reductase in both cells showed a gradual decline reaching a level of 43-44% of the initial level at 96 hr, and remained within 16-17% of the initial value during an incubation period of 192 hr. These results indicate that P450 2C11 in spheroid cells maintained more stable than in the monolayer cells, and that P450 reductase in both cultures declined only moderately, compared with P450s.

Animals↗
PubMed1995

Perirenal mass of Langerhans cell histiocytosis.

A 15-month-old girl with Langerhans cell histiocytosis (LCH), Letterer-Siwe disease, was referred to our hospital in 1984. Whilst on treatment with cytotoxic drugs, a perirenal mass was detected and hydronephrosis became evident when she was 29 months old. Percutaneous nephrostomy tubes were placed in the pelvis, bilaterally and replaced every 6 months. The mass was not completely controlled and chronic pyelonephritis continued. Biopsy of the mass convoluted kidney hilus revealed histiocytic invasion. Although multiple organ systems are involved in LCH and abdominal malignant tumours may be accompanied by hydronephrosis, to our knowledge, this is the first case report of abdominal LCH and the ensuing hydronephrosis. Percutaneous nephrostomy tubes proved useful, but more convenient, less painful and infection-limited approaches need to be designed.

Abdominal Neoplasms↗
PubMed1994

Glomerular clearance and tubular reabsorption of transferrin in microtransferrinuric patients with non-insulin-dependent diabetes.

Our objective was to determine the role of increased glomerular clearance (GC) or reduced tubular reabsorption (TR) of transferrin in producing microtransferrinuria. An infusion of L-arginine was used to inhibit TR of transferrin, permitting the determination of both GC and TR of transferrin in 64 patients with non-insulin-dependent diabetes mellitus (NIDDM), with or without microtransferrinuria. Thirty-one healthy volunteers served as control subjects. The GC of transferrin in NIDDM patients with microtransferrinuria did not differ significantly from that in healthy controls or in NIDDM patients with normal transferrin excretion rates (TfER). No correlation was found between TfER and GC of transferrin in any group of the subjects. However, the TR of transferrin was inversely correlated with TfER in healthy controls and in the NIDDM patients, with or without microtransferrinuria. When transferrin absorption was plotted against the filtered load of transferrin, the regression lines for the three subject groups were parallel. The regression line for NIDDM patients with microtransferrinuria was shifted to the right of those for healthy controls and NIDDM patients with a normal TfER. These findings suggest that microtransferrinuria in patients with NIDDM is caused by the impaired tubular reabsorption of transferrin.

Adult↗
PubMed1993

Higher serum insulin level due to greater total body fat mass in offspring of patients with essential hypertension.

To determine whether the offspring of hypertensive patients (OHP) might have a higher serum insulin level than offspring of normotensive parents, we studied 152 girls in junior high school, 21 of whom had at least one hypertensive parent. The remaining 131 girls had normotensive parents and served as the controls. After an overnight fast, we measured the subjects' height, body weight, blood pressure and body fat mass, and collected blood for assay of serum immunoreactive insulin (IRI), lipids and apolipoproteins. Despite a similar body mass index, the OHP had a significantly greater body fat mass (P < 0.05) and % fat mass (P < 0.05) than the controls. The OHP exhibited a significantly higher serum IRI level than the controls (P < 0.05), but no differences in blood pressure or serum lipids. In the OHP, % body fat mass was significantly correlated with systolic blood pressure (P < 0.05), triglyceride (P < 0.01) and apolipoprotein B (P < 0.01), not observed in controls. The serum IRI of the OHP, but not that of controls, was significantly correlated with systolic blood pressure (P < 0.05), serum triglyceride (P < 0.02) and apolipoprotein B (P < 0.05). Thus, a higher serum IRI level due to an increase in total body fat mass appears to be an inherited trait that contributes to the development of hypertension and dyslipidemia.

Adipose Tissue↗
PubMed1992

Thoracic extramedullary hematopoiesis associated with hereditary spherocytosis.

A 54-year-old man was diagnosed with hereditary spherocytosis. An X-ray of the chest disclosed bilateral round masses in the upper and lower posterior mediastinum. CT showed homogeneous round masses of soft tissue density in the posterior mediastinum. A needle biopsy of the mass showed hyperplastic erythroid bone marrow. Fatty metamorphosis of the masses was observed in CT 2 years after splenectomy but showed no change in size.

Hematopoiesis, Extramedullary↗
PubMed1992

[An autopsied case of progressive systemic sclerosis with anti Wa antibody who showed a rapid progression].

An anti Wa antibody was reported as a new t-RNA related protein antibody in 1986. This autoantibody is now considered specific for the diagnosis of progressive systemic sclerosis (PSS). Up to date only 5 cases with anti Wa antibody have been identified. We report here an autopsied case of PSS with this antibody. A 53 years old female was admitted to our hospital because of dry cough and dyspnea in Sep 1987. There were fine crackles and chest X ray revealed interstitial pneumonia. The progressive respiratory failure was treated by steroid pulse therapy effectively. Sclerotic skin changes of hand began to appear in Sep 1988 and rapidly progressed to arms, chest and forehead by Dec 1988. A skin biopsy confirmed PSS changes. An anti Wa antibody was detected by double immunodiffusion and the protein antigen was associated with t-RNA when immunoprecipitation was conducted. She died of heart failure in July 1989. An autopsy revealed the diffuse fibrotic change of the heart and the lung. Cases with anti Wa antibody were shortly reviewed from the literature.

Autoantibodies↗