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Biomedical subjects

H Ikuta

Publications and source records attributed to H Ikuta.

At least 19 recordsLinked to original sources
PubMed2006

Evidence of two dimensionality in quasi-one-dimensional cobalt oxides.

The quasi-one-dimensional (Q1D) cobalt oxides A(N + 2)Co(n + 1)O(3n + 3) (A = Ca, Sr, and Ba, n = 1 - infinity) were investigated by muon-spin spectroscopy under applied pressures of up to 1.1 GPa. The relationship between the onset Néel temperature T(on)(N) and the interchain distance (d(ic)), which increases monotonically with n, is well fitted by the formula T(N)/T(N,0) = (1 - d(ic)/d(ic,o)(beta), here for T(on)(N) approximately 100 K for Ca(3)Co(2)O(6) (n = 1) and approximately 15 for BaCoCoO(3) (n = infinity at ambient P. The T(on)(N) - d(ic) curve also predicts a large dependence of Y(N) for the compounds with n > or = 5, i.e., in the vicinity of , while the compounds show only a very small effect. Indeed, our high-pressure mu(+) results show that of BaCoO(3) is enhanced by with a slope of 2.2 K(Gpa), whereas no detectable changes by P for both Ca(3)Co(2)O(6) and Sr(4)Co(3)O(9) (n = 2). This clearly confirms the role of the 2D-antiferromagnetic interaction on T(on)(N) in the Q1D cobalt oxides.

Journal Article↗
PubMed2002

Three-dimensional fermi-liquid ground state in the quasi-one-dimensional cuprate PrBa(2)Cu(4)O(8).

The interchain resistivity of PrBa(2)Cu(4)O(8) has been measured in high magnetic fields up to 30 T. Co-herent interchain transport at low temperatures is destroyed by a large magnetic field applied perpendicular to the CuO chains. Comparisons with quasiclassical transport theory provide strong experimental support for a three-dimensional Fermi-liquid ground state in PrBa(2)Cu(4)O(8), despite extreme anisotropy in its electronic properties and the presence of strong electron correlations.

Journal Article↗
PubMed2001

Squalene synthase inhibitors reduce plasma triglyceride through a low-density lipoprotein receptor-independent mechanism.

Inhibitors of squalene synthase are considered to be candidate drugs to reduce both plasma cholesterol and triglyceride. However, little is known about the mechanism of squalene synthase inhibitor-specific effect on plasma triglyceride. In this study, we confirmed the triglyceride-lowering effect of ER-27856, a potent squalene synthase inhibitor prodrug, in rhesus monkeys. To determine the role of low-density lipoprotein (LDL) receptor in the triglyceride-lowering effect of squalene synthase inhibitors, we intravenously administered ER-28448, the active form of ER-27856, to Watanabe heritable hyperlipidemic (WHHL) rabbits for 4 days. In heterozygotes, ER-28448 reduced plasma cholesterol and triglyceride by 52% and 37%, respectively. In homozygous rabbits, in contrast, ER-28448 lowered plasma triglyceride by 40% but did not lower plasma cholesterol. Orally administered ER-27856 reduced plasma triglyceride in homozygous animals but atorvastatin and bezafibrate did not. In hepatocytes isolated from homozygous WHHL rabbits, squalene synthase inhibitors but not atorvastatin reduced triglyceride biosynthesis. These data demonstrate that squalene synthase inhibitors reduced plasma triglyceride through an LDL receptor-independent mechanism, which was distinct from that of the triglyceride-lowering action of atorvastatin or bezafibrate. The reduction of hepatic triglyceride biosynthesis may play an important role in the hypotrigyceridemic action of squalene synthase inhibitors.

Animals↗
PubMed2001

Improved glucose tolerance via enhanced glucose-dependent insulin secretion in dipeptidyl peptidase IV-deficient Fischer rats.

Glucagon-like peptide-1 (GLP-1) is an incretin, which induces glucose-dependent insulin secretion. GLP-1 is rapidly degraded by dipeptidyl peptidase IV (DPPIV) after its release. We investigated whether DPPIV-deficient F344/DuCrj rats show improved glucose tolerance when compared with DPPIV-positive F344/Jcl rats. Oral glucose tolerance test indicated improved glucose tolerance in F344/DuCrj rats, but blood glucose levels of the two strains were almost the same 120 min after the glucose bolus. Valine-pyrrolidide, a DPPIV inhibitor, had no effect on the glucose tolerance of F344/DuCrj rats, but improved that of F344/Jcl rats. Enhanced insulin secretion and high plasma active GLP-1 levels were detected in an intraduodenal glucose tolerance test. Glucose tolerance is improved in DPPIV-deficient F344/DuCrj rats via enhanced insulin release mediated by high active GLP-1 levels. Our results suggest that DPPIV inhibition is a rational strategy to treat diabetic patients by improving glucose tolerance with low risk of hypoglycemia.

Animals↗
PubMed2001

Combined trisomy 9P and Shprintzen syndrome resulting from a paternal t(9;22).

The authors report on a female infant with partial trisomy 9 (pter-->q12) together with partial monosomy 22 (pter-->q11.23) that included DiGeorge critical region (DGCR), as a result of adjacent-2 disjunction. In addition to the clinical features characteristic of trisomy 9p syndrome, the patient had Truncus arteriosus type A2, bilateral hydronephrosis, palatal anomaly, retrognathia, and laryngeal hypotonia, which are likely to be attributed to 22q11.2 deletion. This patient appears to be the first reported case with such unbalanced translocation resulting from a paternal reciprocal translocation. For live birth, the risk for male carrier is 8.7-17.4%. It is important to consider this higher risk when counseling. Precise study concerning the presence of the DGCR can facilitate in the better understanding of the condition.

Abnormalities, Multiple↗
PubMed2000

Anisotropic optical spectra of PrBa2Cu4O8: possible Tomonaga-Luttinger liquid response of the quasi-one-dimensional metallic CuO double chains.

The optical spectra of PrBa2Cu4O8 show large in-plane anisotropy. For the a polarization (E perpendicular chain), the spectrum is characterized by a gap of 1.4 eV, indicating the charge-transfer insulating nature of the CuO2 planes. For the metallic chain direction (E // b), the spectrum deviates from a simple Drude response; reflectivity R(b)(omega) shows a sharp edge at approximately 1 eV but it also shows a dip at approximately 15 meV, which splits the conductivity spectrum into two parts--a zero-energy mode with small weight and a pronounced 40 meV mode. These features are discussed in terms of a Tomonaga-Luttinger liquid in a doped 1D Mott insulator and compared with 1D Bechgaard salts.

Journal Article↗
PubMed1999

Complete agenesis of the dorsal pancreas.

Pancreatic anomalies are occasionally reported, but complete agenesis of the dorsal pancreas is extremely rare. We report a 47-year-old woman with complete agenesis of the dorsal pancreas. This patient initially presented with jaundice. Computed tomography did not reveal the pancreatic corpus or tail. Endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography did not visualize the dorsal pancreatic duct. Choledochojejunostomy was performed because she had obstructive jaundice. At laparotomy, there was an enlarged pancreatic head, but no distal pancreas was seen. Histological examination of the pancreatic biopsy specimen showed scattered islets of Langerhans in diffuse fibrosis, with destruction of the glandular parenchyma. This case was diagnosed as complete agenesis of the dorsal pancreas.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1999

Experimental study on paratumoral injection of cisplatin-loaded microspheres for gastric cancer.

Microspheres from glycolide-L-lactide copolymers incorporating cisplatin (CDDP-MS) were prepared to evaluate the sustained release and anticancer effect by paratumoral injection on the gastric cancer with regional lymphnode metastases induced by VX2 tumor in rabbits. In the first set of experiment, the rabbits were divided into three groups subjected to treatment and compared the tissue cisplatin distribution. In the first group (CDDP-MS pt group), 1 mg/kg of cisplatin was administered by the method of paratumoral injection in the form of CDDP-MS. In the second group (CDDP solution pt group), the same dose was given in the form of CDDP aqueous solution in the same way and in the third group (CDDP solution i.v. group), the same dose was intravenously administered. In the second set of experiment, after twice of each therapy the anticancer effects were compared between CDDP-MS pt and CDDP solution i.v. groups. In results, the platinum concentrations of the tumor and regional lymphnodes were 3.14 +/- 6.22, 0.65 +/- 0.79 micrograms/g in the first group, 0.43 +/- 0.39, 0.16 +/- 0.16 microgram/g in the second group and 0.03 +/- 0.01, 0.07 +/- 0.05 microgram/g in the third group, respectively.

Animals↗
PubMed1998

Clinicopathological features of esophageal cancer simultaneously associated with gastric cancer.

BACKGROUND AND OBJECTIVES: We usually use the stomach for esophageal substitution in the surgical treatment of esophageal cancer, although it is often associated with gastric cancer. In order to improve the likelihood of safe and curative surgery of esophageal cancer, we investigated the clinicopathological characteristics of synchronous esophageal and gastric cancer. METHODS: Among 288 patients with primary esophageal cancer who had undergone esophageal resection, this cancer was associated with gastric cancer in 11 cases, and 1,416 gastric cancer patients operated on during the same period, were analyzed. The clinicopathological characteristics and surgical procedures of the 11 patients were compared with those of the other esophageal cancer patients and with those with the gastric cancer only. RESULTS: There were significant differences between the synchronous double cancer and the gastric cancer only in sex (P < 0.01) and location of the gastric cancer (P < 0.05). All of the patients with the synchronous double cancer were men, and the incidence of patients with cardiac cancer was high. CONCLUSIONS: Our findings suggest that, in cases of synchronous esophageal and gastric cancer, an adequate surgical procedure must be chosen in terms of the stage, location, and operative burden.

Adenocarcinoma↗
PubMed1997

Surgical treatment of patients with psychiatric disorders: a review of 21 patients.

Between January 1985 and September 1994, 21 patients with psychiatric disorders underwent various forms of surgery at our hospital. There were 12 men and 9 women with an average age of 57.6 years. The coexisting psychiatric disorders were schizophrenia in 15 patients, depression in 2, dementia in 2, mental retardation with epilepsy in 1, and Parkinson's disease in 1. All the patients had been receiving neuroleptic medications for a long period. The indications for surgery were: cholelithiasis in 6 patients, acute appendicitis in 4, perforation of the small intestine in 3, incarceration of an inguinal hernia in 2, and esophageal cancer, stomach cancer, bleeding from a gastric ulcer, perforation of a duodenal ulcer, strangulating ileus, and burns in 1 patient each, respectively. All of the patients who underwent elective surgery were given epidural anesthesia with or without general anesthesia. Antipsychotic medications were given until just prior to surgery and recommenced concurrent with the first meal. Abnormal behavior was observed in 11 patients (52.4%) postoperatively, but all the patients were discharged in accordance with recovery from their surgical disorder. Intra- and postoperative hypotension resistant to intravenous catecholamine administration was recognized in 9 patients (42.9%), and this peculiar complication should be borne in mind when patients with psychiatric disorders require surgical management.

Adult↗
PubMed1997

A case of esophagectomy for corrosive esophageal stricture caused by swallowing strong alkali. A case report.

We report herein the case of a 22-year old woman who underwent esophagectomy for corrosive esophageal stricture. This patient with mental disturbance swallowed a strong alkali in a suicide attempt and suffered from esophageal stenosis instead of steroid therapy. Because the stiffness and stricture of the esophagus proved to be refractory, transhiatal esophagectomy by blunt finger with gastroesophagostomy was performed four months after injury. Operative findings revealed severe stiffness and inflammation of the esophagus which had spread to the adjacent organs, especially the carina. As for pathological findings, most of the esophageal mucosa showed defects resulting from infiltration of inflammatory cells and capillary vascularization from the lamina propria to the extra-esophageal wall. The postoperative course was uneventful and perioperative psychological state had been stable leading to a decrease in tranquilizer dosage. This experience indicates that esophagectomy is the treatment of choice for such mental disturbed patients with severe stenosis.

Adult↗
PubMed1996

Bone scintigraphy in detection of bone invasion by oral carcinoma.

Detecting osseous involvement is clinically important in the management of oral carcinoma. Thirty-one patients with osseous involvement due to oral carcinoma who underwent panoramic radiography and bone scintigraphy were evaluated retrospectively. Bone scintigraphy confirmed osseous involvement in all 31 (100%) of these patients. In 27 (87%) of 31 patients with osseous involvement, both the panoramic radiogram and bone scintigram were positive. In the remaining four patients (13%), bone scintigram was positive for mandibular or maxillary invasion, while panoramic radiogram was negative. There were no instances of an abnormal radiogram with a normal bone scintigram. These findings strongly suggest that bone scintigraphy is more sensitive than panoramic radiography in detecting osseous involvement of the mandible and maxilla due to oral carcinoma. Furthermore, bone scintigraphy was a critical pre-surgical in determining the extent of the osseous involvement.

Carcinoma, Squamous Cell↗
PubMed1996

Lenńox-Gastaut syndrome associated with leukoencephalopathy.

We report a 13-year-old boy with Lennox-Gastaut syndrome (LGS) associated with leukoencephalopathy. He was diagnosed with unclassified acute lymphocytic leukemia at the age of 3 years. After initial chemotherapy, he received intravenous methotrexate (total dosage 1,035 mg), intrathecal methotrexate (total dosage 221 mg), and whole brain irradiation (2,400 cGy). From about the age of 8 years, he developed slurred speech, hyperactivity, and mental deterioration. Cranial CT revealed calcification of the subcortical white matter. At age 9 years, he exhibited tonic seizures and atonic seizures. EEG showed diffuse slow spike-wave discharges, which are characteristic of LGS. Although multiple antiepileptic drugs have been prescribed, the frequency of seizures remains unchanged and his mental state is becoming progressively worse.

Adolescent↗
PubMed1996

A study of patients having survived curative operation for esophageal cancer for five years or more.

In order to analyze the prognostic factors for curatively resected esophageal cancer, 42 patients who had survived their operation more than 5 years (long-term survivors) were compared for clinicopathologic items with 30 recurrent patients who had died within 5 years postoperatively (recurrent cases). Moreover, to estimate the prognosis for the current survivors, we investigated the cause of death of long-term survivors who had died. This comparison showed that the rate of lymphatic invasion was 36.4% and of blood vessel invasion 19.4% for the survivors, much lower than those of the recurrent cases which were respectively 62.1% and 31.0%. It was found that the significantly unfavorable prognosis-determinant factors was lymphatic invasion (p < 0.05). Ten out of 12 n (+) survivors (83.3%) had single metastasing region, one in the neck, three in the mediastinum and six in the abdomen. This was not significantly different from the recurrent cases, of whom, ten out of 14 n (+) cases had a single metastasing region, six in in the mediastinum and four in the abdomen. As for the number of metastatic lymph nodes, nine out of 12 n (+) survivors (75%) had only one matastatic lymph node, and none of them had more than three. On the other hand, two of the recurrent cases had more than three. Of the 42 long-term survivors, 21 patients are still alive (current survivors' average age: 70.1 +/- 7.9) and 21 have died. The cause of death was recurrence in six cases, metachronous primary malignant tumor in three, other disease in six and unknown in six. The average age of death was 62.1 +/- 10.3 in cases of recurrence or double cancer, and 71.8 +/- 9.5 in others. The former were thus significantly younger than the latter (p < 0.05).

Cause of Death↗
PubMed1995

[A case of gastric cancer with multiple liver metastasis responding to combined therapy with UFT and mitomycin C].

A 66-year-old female was admitted to our hospital with the complaint of anorexia and epigastric pain. Examination of the gastrointestinal tract revealed Borrmann III type gastric carcinoma, 5 cm x 5 cm in size, in the lesser curvature of the stomach. Multiple liver metastases were detected on abdominal computed tomography. In January 1993, she underwent subtotal gastrectomy as a palliative therapy. Pathological diagnosis of the resected specimen was poorly differentiated adenocarcinoma. Two weeks after operation, administration of UFT (300-450 mg/day, orally) and mitomycin C (12 mg/three months, intravenously) was started. This chemotherapy had to be discontinued within six months because of its severe side effects, such as leukopenia and acral erythema. However, a marked reduction in the size of the metastatic liver tumors was observed on abdominal computed tomogram, and the patient is now (15 months after operation) alive without local recurrence or re-growth of liver metastatic tumors.

Adenocarcinoma↗