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Biomedical subjects

J Iwai

Publications and source records attributed to J Iwai.

At least 37 records · Page 2Linked to original sources
PubMed1997

The role of ERCP in biliary atresia.

BACKGROUND: It is not easy to discriminate between infantile hepatitis and biliary atresia in spite of several diagnostic tests including laboratory analyses, ultrasound, and hepatobiliary scans. ERCP is the most useful procedure for visualization of the extrahepatic biliary system, but ERCP is still an uncommon procedure in children. METHODS: ERCP examination was performed in 52 infants with biliary atresia (10 with infantile hepatitis, 5 with congenital biliary dilatation, 3 with paucity of intrahepatic bile duct, 2 with duodenal atresia, and 1 with postoperative jaundice of hepatoblastoma) aged from 8 days to 300 days (mean, 71 days). RESULTS: ERCP was successful in 47 with biliary atresia, in 9 with infantile hepatitis, and 10 with another disease. Liver biopsy was performed in 1 infant with hepatitis in whom the cannulation failed; in 9 with hepatitis in whom the cannulation was successful, exploratory laparotomy could be avoided. The ERCP findings in 46 patients with biliary atresia (excluding 1 in whom evaluation could not be performed because of poor x-ray quality) were classified into four patterns. CONCLUSIONS: A success rate of ERCP examinations in infants was 88%, so ERCP is recommended to make a correct decision regarding the need for surgery in cholestatic disorders.

Biliary Atresia↗
PubMed1997

Detection of tumor thrombus in children using color Doppler ultrasonography.

Color Doppler ultrasonography (CDUS), which provides information regarding both the tissue and the blood flow simultaneously in real time, is a relatively new and noninvasive technique for the evaluation of organ perfusion. The authors investigated the usefulness of CDUS in the detection of tumor thrombus in 34 children who had malignant tumor (21 neuroblastomas, 2 Wilms' tumors, 5 hepatoblastomas, 2 rhabdomyosarcomas, and 4 others) who underwent CDUS between April 1992 and March 1995 in our department. The CDUS showed tumor thrombus in four patients (11.8%). Three thrombi (in one patient each with neuroblastoma, Wilms' tumor, and hepatoblastoma) were situated in the inferior vena cava, and one (in a patient who had hepatoblastoma) in the portal vein. Each tumor thrombus was monitored and followed up using CDUS every month during the entire clinical course; two of the four thrombi remained despite intensive treatments. The authors have found CDUS to afford rapid and noninvasive detection of tumor thrombus, and it proved useful not only in the detection of tumor thrombus but also in its follow-up in these children who had malignant tumor.

Child, Preschool↗
PubMed1997

Endoscopic variceal ligation using a clipping apparatus in children with portal hypertension.

BACKGROUND AND STUDY AIMS: Endoscopic variceal sclerotherapy (EVS) is a procedure frequently used to control bleeding from esophageal varices in adults. The use of EVS has been restricted in children due to the associated risks. The present paper describes the safety and efficacy of a new apparatus for endoscopic variceal ligation with clipping (EVLC). PATIENTS AND METHODS: Endoscopic variceal ligation using a clipping apparatus (HX-3 L, Olympus, Tokyo, Japan), was carried out in 12 children with portal hypertension (four with extrahepatic portal vein obstruction and eight with congenital biliary atresia; four boys and eight girls, age range 2-14 years). A total of 417 variceal clipping procedures were carried out in 56 separate EVLC sessions; 118 esophageal varices and 65 gastric fundic varices were ligated using 417 clips. Initially, the EVLC sessions were repeated at approximately monthly intervals until the varices were eradicated, but the interval was gradually extended to twice a year or once a year. RESULTS: Varices were successfully ligated at the first attempt in 414 (99.3%) of the 417 clipping procedures. The esophageal varices were initially eradicated in all patients. The follow-up period ranged from nine to 48 months, and complete variceal eradication or reduction of the grade of the varices was obtained in 11 of the 12 patients after initial eradication during this period. CONCLUSIONS: These data indicate that EVLC offers advantages in the treatment of patients with esophageal varices combined with gastric fundic varices.

Adolescent↗
PubMed1997

Endoscopic retrograde cholangiopancreatography (ERCP) in biliary tract disease of infants less than one year old.

We performed a total of 75 examinations with endoscopic retrograde chlangiopancreatography (ERCP) in 73 infants aged from 8 days to 300 days (mean 71 days) between 1977 and 1995. ERCP examination was performed with a prototype duodenoscope and was successful in 47 of 52 examinations in biliary atresia, 9 of 11 in neonatal hepatitis, all 4 in paucity of intra-hepatic bile duct, 4 of 5 in congenital biliary dilatation, 1 of 2 in duodenal stricture, and 1 case of in postoperative jaundice of hepatoblastoma. In 46 infants with biliary atresia, excluding one in whom the findings could not be evaluated due to poor x-ray image quality, we distinguished the following four patterns of ERCP findings: Pattern 1, only the pancreatic duct could be demonstrated and no bile duct was visualized (76%); Pattern 2, only a part of the distal common bile duct with the pancreatic duct was visualized (2%); Pattern 3, the entire length of the common bile duct with the pancreatic duct was visualized without the gallbladder and the common hepatic duct (4%); and Pattern 4, the common bile duct and the gallbladder with the pancreatic duct were visualized without the common hepatic duct (18%). In all of these 46 patients, laparotomy, an operative cholangiogram, and histological evaluation of the biliary duct were performed. In 9 neonates with neonatal hepatitis, the biliary tract was opacified and biliary atresia was excluded. Laparotomy was thus avoided in these neonates. There was no complication caused by either ERCP or by anesthesia.

Anesthesia↗
PubMed1996

Renal impairment after surgical resection of neuroblastoma.

Postoperative renal impairment was observed in 6 of 58 patients with neuroblastoma treated between November 1982 and March 1994. To clarify the clinical characteristics of these patients (renal-impairment group), they were compared with 26 patients treated during the same period who did not have renal impairment (no-impairment group). The incidence of primary retroperitoneal tumor and invasion of the hilum renalis was clearly higher in the renal-impairment group than in the group with no impairment. However, no significant difference was observed with respect to age, tumor laterality, or stage of disease. The results of postoperative biochemical examinations showed that the serum concentrations of lactic dehydrogenase were significantly higher in the renal-impairment group. In the group with renal impairment, the mean maximal body temperatures on the first, second, and third postoperative days were 38.7 degrees C, 38.6 degrees C, and 38.1 degrees C, respectively. These were higher than those of the no-impairment group. For patients with these risk factors, intraoperative prophylactic measures and early postoperative renal blood flow evaluation (in anticipation of postoperative renal impairment) are considered necessary.

Adrenal Gland Neoplasms↗
PubMed1995

Bone marrow metastasis of neuroblastoma analyzed by MRI and its influence on prognosis.

Bone marrow metastases (BM mets) of neuroblastoma were analyzed by magnetic resonance imaging (MRI). BM mets were demonstrated in 45 femurs of 23 patients with neuroblastoma by MRI. They were classified into two patterns, nodular (N) type and diffuse (D) type, on MRI, with an incidence of 16% (7/45) and 84% (38/45), respectively. No bone metastases (B mets) were accompanied by N type BM mets, whereas all of them were accompanied by D type BM mets. The rate of disappearance of N type BM mets after chemotherapy was 100% (7/7) and was significantly higher than that (26%, 10/38) of D type BM mets. The rate of disappearance (58%, 11/19) of BM mets in bones without associated B mets was also significantly higher than that (23%, 6/26) of BM mets in bones with associated B mets. BM mets present in bones with B mets tended to persist after chemotherapy. The survival rate of patients with residual BM mets after chemotherapy was significantly lower than that of patients without residual BM mets. This suggests that powerful systematic chemotherapy and additional targeted therapy to lesions remaining after chemotherapy are needed to improve the cure rate of patients with advanced neuroblastoma.

Bone Marrow↗
PubMed1995

Effect of green tea rich in gamma-aminobutyric acid on blood pressure of Dahl salt-sensitive rats.

gamma-Aminobutyric acid (GABA) is known to be involved in the regulation of blood pressure by modulating the neurotransmitter release in the central and peripheral sympathetic nervous systems. This study investigated the antihypertensive effect of green tea rich in GABA (GABA-rich tea) in young and old Dahl salt-sensitive (S) rats. GABA-rich tea was made by fermenting fresh green tea leaves under nitrogen gas. In experiment 1, 21 11-month-old rats, fed a 4% NaCl diet for 3 weeks, were given water (group W), an ordinary tea solution (group T), or a GABA-rich tea solution (group G) for 4 weeks. The average GABA intake was 4.0 mg/rat per day. After 4 weeks of the treatment, blood pressure was significantly decreased in group G (176 +/- 4; P < .01) compared with group W (207 +/- 9) or group T (193 +/- 5 mm Hg). Plasma GABA levels were more elevated in group G (111 +/- 54) than in group W (not detectable) or group T (14 +/- 8 ng/mL; P < .01 v G). In experiment 2, 21 5-week-old rats, fed a 4% NaCl diet, were divided into groups W, T, and G. The average GABA intake was 1.8 mg/rat per day. Body weight or chow and beverage consumption did not differ significantly among the three groups. After 4 weeks of the treatment, although blood pressure was comparable in groups W and T (165 +/- 3 v 164 +/- 5 mm Hg, mean +/- SE), it was significantly lower in group G (142 +/- 3 mm Hg) than in the other groups (P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Blood pressure regulates platelet-derived growth factor A-chain gene expression in vascular smooth muscle cells in vivo. An autocrine mechanism promoting hypertensive vascular hypertrophy.

To clarify the role of PDGF A-chain in hypertensive vascular hypertrophy of spontaneously hypertensive rats (SHRs), we studied levels of PDGF A-chain gene expression and transcription factors related to the gene in vascular smooth muscle cells (VSMCs) of SHRs in vivo. RNase protection assay and in situ hybridization showed that PDGF A-chain mRNA levels in VSMCs of SHRs were twofold higher than in those of normotensive Wistar-Kyoto rats. Gel retardation assays showed that levels of Sp1 and AP-2 in VSMCs of SHRs were twofold more abundant than in those of Wistar-Kyoto rats. Treatment with four pharmacologically different species of antihypertensive drugs for 2 wk decreased the levels of both PDGF A-chain mRNA and Sp1, but not AP-2 level in VSMCs of SHRs with regression of aortic hypertrophy, indicating that increases in levels of both PDGF A-chain mRNA and Sp1 in VSMCs of SHRs were associated with high blood pressure. These results suggest that high blood pressure is a stimulus which upregulates PDGF A-chain gene expression in VSMCs of SHRs, resulting in an autocrine enhancement in hypertensive vascular hypertrophy, and that the activation of the gene may be mediated through increases in Sp1 in these cells.

Animals↗
PubMed1994

Angiotensin-converting enzyme inhibitor increases angiotensin type 1A receptor gene expression in aortic smooth muscle cells of spontaneously hypertensive rats.

To examine the regulation of angiotensin receptors in vascular smooth muscle cells, we studied the effects of antihypertensive drugs on angiotensin type 1A (AT1A) receptor gene expression in aortic smooth muscle cells (ASMCs) from spontaneously hypertensive rats (SHRs) using both ribonuclease protection assay and reverse-transcription polymerase chain reaction. An increase in AT1A receptor gene expression in ASMCs of SHRs was induced by treatment with an angiotensin converting enzyme inhibitor (enalapril) for 2 weeks and 4 weeks, but not by other types of antihypertensive drugs such as alpha-blocker (doxazosin), alpha, beta-blocker (arotinolol), Ca antagonist (nicardipine) or vascular smooth muscle relaxant (hydralazine). Since all antihypertensive drugs lowered the blood pressure of the rats almost equally, our results suggest that AT1A receptor gene expression in ASMCs of SHRs may be regulated by the vascular renin-angiotensin system.

Animals↗
PubMed1994

Enhancement of hypertension and renal injury by salt-loading during chronic nitric oxide inhibition. Effects of TCV-116, a novel angiotensin II receptor antagonist.

Endothelium-derived nitric oxide (EDNO) and angiotensin II play a role in the regulation of vascular tone and sodium handling. The objective of this study was to determine the role played by angiotensin II in mediating the arterial pressure and renal response to increments in sodium intake during chronic EDNO inhibition. Six groups of Wistar rats were studied; they were fed either a normal sodium diet (groups I, II, and III) or a high sodium diet (groups IV, V and VI). Rats in groups II, III, V and VI were placed on oral L-N-nitroarginine-methyl ester (L-NAME) for 4 weeks. In groups III and VI, the angiotensin II receptor antagonist, TCV-116, was administered. A significant increase in blood pressure was observed in group V compared with group II at the end of the experimental period. TCV-116 attenuated the L-NAME-induced hypertension in both group III and group VI. Urinary protein excretion and the glomerular sclerotic injury score in group V were greater than in group II. TCV-116 attenuated the proteinuria and glomerular injury induced by chronic EDNO inhibition in the groups with normal (group III) and high sodium intake (group IV). Systemic hypertension and glomerular injury were enhanced by salt loading during EDNO inhibition, and the angiotensin II receptor antagonist, TCV-116, attenuated this salt-induced increase in blood pressure and renal injury, suggesting that EDNO may counteract the renal effects of angiotensin II.

Angiotensin Receptor Antagonists↗
PubMed1994

Identification of human DAN gene, mapping to the putative neuroblastoma tumor suppressor locus.

The expression of DAN gene (previously designated as N03 gene) is significantly reduced in a variety of transformed rat fibroblasts, including v-src- (SR-3Y1), SV40- and v-mos-transformed 3Y1 cells, compared with that in parental 3Y1 cells. Recently, DAN gene has been shown to possess a tumor suppressive activity when it is overexpressed in SR-3Y1 cells (Ozaki & Sakiyama, 1994). To assess the involvement of DAN gene with human neoplasms, we have isolated human DAN counterpart from a normal lung cDNA library by using rat DAN cDNA as a probe, and determined its chromosomal location. Human DAN gene mapped to chromosome 1p36.11-p36.13, which is well known to show highly significant linkage with the genesis and/or progression of human neuroblastoma. Southern blot analysis on tumor DNA from 26 patients with neuroblastoma has detected three patients showing genomic rearrangement or deletion within or closely linked to the DAN gene locus. Collectively, we propose that human DAN gene is a possible candidate for a tumor suppressor gene of human neuroblastoma.

Amino Acid Sequence↗
PubMed1993

Increased endothelial gene expression of angiotensin AT1A receptor in cyclosporine induced hypertensive rats.

We examined the gene expression of angiotensin AT1A receptors in aortic endothelial cells of cyclosporine induced hypertensive rats using reverse transcribed polymerase chain reaction method. The gene expression of angiotensin AT1A receptors in aortic endothelial cells of cyclosporine induced hypertensive rats showed a two-fold increase when compared with that in normotensive control rats. These results raise a possibility that the up-regulation of endothelial angiotensin AT1A receptors participates in the pathogenesis of cyclosporine induced hypertension.

Angiotensin I↗
PubMed1993

Evaluation of bone marrow metastasis of neuroblastoma and changes after chemotherapy by MRI.

To evaluate the usefulness of MRI for diagnosing bone marrow metastasis of neuroblastoma, we compared MRI findings with histological findings. MRI was performed 26 times in 20 patients with neuroblastoma to detect metastasis to the bone marrow of the femur and tibia. Abnormal areas observed by MRI were histologically examined. The lesion visualized by MRI as a low-intensity area on T1-weighted images and as a high-intensity area on T2-weighted images was histologically confirmed to be neuroblastoma in 81% (17/21). The percentage varied according to the treatment state: 89% (8/9) by MRI imaging performed before the initiation of chemotherapy, 67% (6/9) within 3 weeks after cessation of chemotherapy (during chemotherapy), and 100% (3/3) in recurrent cases 1 year or more after chemotherapy. During the follow-up period after chemotherapy, tissue with signal intensities similar to that of bone marrow was observed in a speckled pattern in the intramedullary space on T1- and T2-weighted images. This tissue was histologically demonstrated to be normal bone marrow and was considered to be bone marrow remaining after chemotherapy. In this small series, histological findings supported the results of MRI, confirming the usefulness of MRI for diagnosing bone marrow metastasis of neuroblastoma. However, bone marrow metastasis after chemotherapy was difficult to evaluate by comparing signal intensities alone.

Adolescent↗
PubMed1993

Imaging of neuroblastoma in patients identified by mass screening using urinary catecholamine metabolites.

Between April 1983 and August 1991, mass screening in Chiba Prefecture found 25 infants to be positive for neuroblastoma based on elevated urinary levels of catecholamine metabolites. Ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), bone scintigraphy (BS), and 67Ga scintigraphy (GS) detected neuroblastomas in 12 of the 25 infants. The primary site of tumor was the mediastinum in 1 patient, the adrenal gland in 7, retroperitoneum in 3, and pelvis in 1. To determine the accuracy of each imaging technique, the percent sensitivity (SE), percent specificity (SP), and percent accuracy (AC) were determined for each technique from surgical findings and a follow-up study. MRI showed the highest diagnostic accuracy (100% for SE, SP, and AC), followed by CT (100%, 92%, 96%), US (82%, 92%, 88%), BS (58%, 100%, 80%), and GS (42%, 85%, 64%) in that order. MRI is most suitable for the imaging of individuals judged to be positive in the mass screening for neuroblastoma because of the advantages of visualization of the spread of tumor and the relationship of tumor to the great blood vessels, important determinants of resectability and therapy.

Adrenal Gland Neoplasms↗
PubMed1993

Possible radical scavenging properties of cicletanine and renal protection in Dahl salt sensitive rats.

Much interest in cicletanine, a novel antihypertensive drug, has grown because it uniquely stimulates prostacyclin (PGI2) production and may, thereby, provide further cardiovascular protection. We postulated that cicletanine may be an antioxidant, and assessed its ability to protect the kidney in Dahl salt-sensitive (Dahl S) rats on a high salt diet. Cicletanine eradicated in vitro a stable radical, DPPH, and decreased the lipid peroxidation both in rat brain homogenate and in a xanthine-xanthine oxidase (X-XOD) superoxide generating system. Furthermore, cicletanine attenuated the inhibition of PGI2 synthase activity by 15HPETE. However, cicletanine did not exhibit superoxide dismutase-like activity in X-XOD system, suggesting that it behaves primarily as a hydroxy radical scavenger. A 6 week cicletanine treatment reduced blood pressure in Dahl S rats fed a high salt diet, and ameliorated functional and morphological injury to the kidney. This attenuation of glomerular sclerosis correlated with the attenuation of lipid peroxidation in the kidney homogenate. These data indicate that cicletanine is an antioxidant that protects the kidney from salt-induced hypertension in Dahl salt-sensitive strain rats.

Animals↗
PubMed1993

Oxygen radical scavengers and renal protection by indapamide diuretic in salt-induced hypertension of Dahl strain rats.

In addition to the hemodynamic components, the roles of various humoral factors have been emphasized in the progression of vascular and renal injury in hypertension. Radical scavenging properties have attracted much attention in this field. This article discusses the implication of antioxidant properties of the antihypertensive diuretic indapamide on renal injury in Dahl salt-sensitive (Dahl S) rats. Hydroxyl radicals, oxygen radicals toxic to cellular membranes, are eradicated by indapamide in different assay systems, e.g., reduction of alpha-alpha-diphenyl-beta-picrylhydrazyl, rat brain homogenate, or xanthine-xanthine oxidase systems. Such antioxidant effects of indapamide are primarily due to inhibition of lipid peroxidation induced by hydroxyl radicals, and this mechanism may stimulate prostacyclin generation through activation of prostacyclin synthase. In fact, the antioxidant properties of indapamide are well expressed in vivo as well; indapamide treatment reduced oxygen radicals in the kidney of Dahl S rats with hypertension. This was accompanied by a functional improvement of the kidney; decreases in urinary protein and n-acetylglucosaminidase excretion and an increase in glomerular filtration rate were observed. In addition, indapamide morphologically ameliorated the renal injury, and decreased glomerular sclerosis score, arterial injury, and renal tubular injury. Trichloromethiazide reduces blood pressure similar to that produced by indapamide. However, trichloromethiazide did not lead to reduction of oxygen radicals in the kidney, and did not improve the functional disturbance or morphological injury seen in Dahl S rats. These results indicate that indapamide has antioxidant properties, and in addition to blood pressure reduction, such radical scavenging effects may contribute to its beneficial effects on renal function in vivo.

Animals↗