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S Okada

Publications and source records attributed to S Okada.

At least 361 records · Page 20Linked to original sources
PubMed1998

Isolated lissencephaly sequence with balanced chromosome translocation involving 17p13.3.

We describe a patient with isolated lissencephaly sequence (ILS) who had a de novo balanced translocation with breakpoint at 8p11.23 and 17p13.3. She developed infantile spasms and had severe developmental delay. There was no apparent deletion of 17p13.3 on fluorescence in situ hybridization (FISH) analysis. The breakpoint was located centromeric to the Miller-Dieker syndrome (MDS) marker (D17S379), and telomeric to the marker D17S1566, which is located centromeric to the LIS1 gene. This is the second reported case of ILS with balanced translocation. It is suspected that the breakpoint of 17p13.3 in this patient is located in the responsible gene for ILS.

Brain↗
PubMed1998

A case of giant axonal neuropathy showing focal aggregation and hypophosphorylation of intermediate filaments.

We report here the clinicopathological features of a typical case of giant axonal neuropathy (GAN). Scanning electron microscopy of the hair of this case revealed an extraordinarily irregular cuticle. Focal accumulation of intermediate filaments in axons, Schwann cells, muscle fibers and skin fibroblasts were also found under an electron microscopy. When examined immunocytochemically, muscle fibers exhibited local disruption of the filamentous network in the subsarcolemmal space and in the central cytoplasm accompanied by focal accumulation of desmin. The intracellular network of vimentin was also disrupted, exhibiting global accumulation in some of the cultured skin fibroblasts. Decreased interneurofilament spacing was found in enlarged axons, suggesting the presence of hypophosphorylation of neurofilaments in this patient. These findings suggest general disorganization, abnormal distribution and possible defective phosphorylation of intermediate filaments in GAN.

Axons↗
PubMed1998

Cupric nitrilotriacetate induces oxidative DNA damage and apoptosis in human leukemia HL-60 cells.

Recent reports have implicated a possible role of reactive oxygen species (ROS) in the induction and mediation of apoptosis and DNA damage. Oxidative DNA base modification induced by cupric nitrilotriacetate (Cu-NTA) and the following apoptosis were observed in human promyelocytic leukemia HL-60 cells. We measured the level of ROS in the cells by using a fluorescence probe, 2',7'-dichlorofluorescein diacetate (DCFH-DA), and the amount of a modified DNA base, 8-hydroxydeoxyguanosine (8-OHdG) by HPLC-ECD. It was found that Cu-NTA exposure significantly enhanced ROS and 8-OHdG formation in the cells. Meanwhile, we observed both DNA fragmentation and morphological changes characteristic of apoptosis, which was also determined quantitatively by flow cytometry and showed dose- and time-dependent manners. Furthermore, several antioxidants such as dimethyl sulfoxide (DMSO), superoxide dismutase (SOD), and catalase were used to detect whether the apoptosis could be blocked. Only DMSO protected against this form of cell death. To elucidate molecular events in the apoptosis, expressions of Bcl-2 protein family members, such as Bcl-2, Bcl-X and Bax, and heat shock protein 70 (HSP-70) were measured by western blotting using specific antibodies. The levels of Bax and Bcl-Xs remained largely unchanged, but the Bcl-2 and Bcl-XL expression showed down-regulation. After 24 h incubation in the presence of copper, the levels of Bcl-2 and Bcl-XL reduced about 33.8% and 51.1% compared with untreated cells, respectively. Furthermore, after 16 h incubation, the level of HSP-70 expression was about 3.4-fold greater than that in untreated cells, suggesting that HSP-70 is important in increasing resistance to oxidative stress induced by Cu-NTA. But overexpression of HSP-70 failed to protect HL-60 cells from apoptosis induced by Cu-NTA. We inferred that Cu-NTA may induce oxidative DNA damage through free radical injuries, which may turn on the apoptosis in HL-60 cells.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1998

Interfacial catalysis by phospholipases at conjugated lipid vesicles: colorimetric detection and NMR spectroscopy.

BACKGROUND: Self-assembled conjugated polymers are rapidly finding biological and biotechnological applications. This work describes a synthetic membrane system based on self-assembled polydiacetylenes, which are responsive to the enzymatic activity of phospholipases - a ubiquitous class of enzymes that catalyze the hydrolysis of phospholipid molecules embedded in cell membranes. RESULTS: We show that phospholipases are active at bilayer vesicles composed of the natural enzyme substrate, dimyristoylphosphatidylcholine (DMPC), and a synthetic pi-conjugated polymerized lipid based on polydiacetylene (PDA). In addition, the enzymatic reaction induces an optical transition in the surrounding PDA matrix, visible to the naked eye. Nuclear magnetic resonance spectroscopy confirms the occurrence of enzymatic catalysis and reveals the fate of the cleavage products. CONCLUSIONS: The results indicate that the structural and color changes of the PDA matrix are directly related to interfacial catalysis by phospholipase. This novel biocatalytic method of inducing optical transitions in conjugated polymers might lead to new approaches towards rapidly screening new enzyme inhibitor compounds.

Acetylene↗
PubMed1998

Elevated serum level of thioredoxin in patients with hepatocellular carcinoma.

Thioredoxin (TRX) is known to contain an active site with a redox-active disulfide and has various biological activities. The objective of the present study was to investigate whether circulating TRX levels are elevated in patients with chronic hepatitis (CH) or liver cirrhosis (LC) and hepatocellular carcinoma (HCC). An anti-TRX monoclonal antibody and polyclonal antibodies that specifically recognize TRX, were generated and used for the development of an ELISA system to measure TRX levels in human serum. The geometric mean and its 95% confidence interval of serum level of TRX in healthy volunteers was 81.75 ng/ml (74.60-89.59 ng/ml). The serum level of TRX in LC/CH patients without HCC was 80.87 ng/ml (69.66-93.88 ng/ml). The value was not statistically different from that in serum from normal volunteers (p=0.69). In contrast, the serum level of TRX in patients with HCC was 147.35 ng/ml (125.53-172.96 ng/ml), which was significantly higher when compared with the level in serum of normal volunteers (p<0.001) and in serum of LC/CH patients without HCC (p<0.001). In four patients with HCC, the initially high level of serum TRX (>150 ng/ml) decreased below 150 ng/ml after surgical removal of the tumor. The data reported herein revealed that patients with HCC had a significantly elevated serum level of TRX, suggesting that measurement of serum of TRX might be a useful clinical parameter when HCC is suspected.

Adult↗
PubMed1998

Past exposure to hepatitis B virus as a risk factor for hepatocellular carcinoma in patients with chronic liver disease.

The aim of the study was to determine whether past exposure to hepatitis B virus (HBV) influences the risk of the development of hepatocellular carcinoma (HCC) in Japanese patients with chronic liver disease (CLD). We conducted a hospital-based case-control study of 141 HCC patients with CLD and 151 controls with CLD but without HCC. Past exposure to HBV was assessed by antibody to hepatitis B core antigen (anti-HBc) positivity. Ninety-two patients (65%) with HCC were anti-HBc positive compared with 65 patients (43%) with CLD alone (P < 0.01). A multivariate analysis using logistic regression modelling revealed that anti-HBc positivity significantly increased the risk of the development of HCC [odds ratio (OR) 2.0, P = 0.01]. In the anti-HBc-positive patients, a significantly increased risk of HCC was seen among the patients positive for anti-HBc alone (OR, 2.6; P < 0.01). However, a significant OR was not obtained among the patients with a transient HBV infection implied by positivity for both antibody to hepatitis B surface antigen and anti-HBc (OR, 1.5; P = 0.48). These results indicate that past exposure to HBV is a risk factor for HCC in Japanese CLD patients, especially when they have no serological evidence of immunity to HBV.

Adult↗
PubMed1998

Allogeneic peripheral stem cell transplantation using positively selected CD34+ cells from HLA-mismatched donors.

We examined five children who underwent allogeneic peripheral stem cell transplantation (PSCT) using positively selected CD34+ cells from three or two loci-mismatched donors. CD34+ cells mobilized from peripheral blood were separated by immunomagnetic beads. CD34+ cells at 2.2-6.2 x 10(6)/kg were transplanted into three patients with refractory leukemia, a patient with relapsed medulloblastoma and a patient with Fanconi's anemia following a conditioning regimen which included irradiation, alkylating agents and antithymocyte globulin treatment. The number of infused CD3+ cells included in grafts was 2.3-22.7 x 10(4)/kg. Four patients achieved engraftment and hematopoietic reconstitution (> 5 x 10(8)/l of neutrophils on day 10 or 11). Graft rejection was observed in the patient with Fanconi's anemia, but a rapid engraftment was obtained after second PSCT. Although no prophylactic agents other than ATG (included in the conditioning regimen) were used, greater than grade I acute GVHD was not observed, but limited chronic GVHD was observed in two patients. The two patients with leukemia relapsed on days 103 and 210, respectively, and the patient with medulloblastoma died of disease on day 159. The patient with Fanconi's anemia died of fungal infection. CMV and HHV-6 diseases developed in four and two patients, respectively. Thus, although SCT using positively selected peripheral CD34+ cells may be an alternative approach for overcoming graft rejection and GVHD from HLA- mismatched donors, persistent immune deficiency attributing to extremely low numbers of T cells in grafts can potentially lead to reactivation of herpes viruses.

Adolescent↗
PubMed1998

Double-conditioning regimens consisting of thiotepa, melphalan and busulfan with stem cell rescue for the treatment of pediatric solid tumors.

Major dose-limiting factors of high-dose thiotepa (TEPA) and melphalan are life-threatening mucositis and neurotoxicity. To administer a maximum dose of these drugs safely and to obtain a maximum anti-cancer effect, a double-conditioning regimen with a single grafting, two cycles of administration of a combination of TEPA (300-600 mg/m2) plus melphalan (70-150 mg/m2) with a 1-week interval was attempted in 20 patients with pediatric advanced or chemotherapy-resistant solid tumors (seven rhabdomyosarcoma, four hepatoblastoma, three neuroblastoma and four other malignancy). Combinations of TEPA plus melphalan/busulfan (Bu) (8-10 mg/kg) and TEPA plus Bu were given to four and two patients with brain tumors, respectively. In an additional two patients, three cycles of drug administration were performed. According to the results of the dose-escalating study, the maximum tolerable doses of TEPA and melphalan for children aged 2 years old or older were 1000 mg/m2 and 280 mg/m2, respectively. Mucositis was dose-limiting. Renal toxicity was also dose-limiting in young children (<2 years old). There were two treatment-related deaths (7%) (fungal pneumonia and renal tubular acidosis). Among 13 patients who received high-dose chemotherapy during CR, 10 are alive with no evidence of disease (15-59 months, median: 35 months) and in 13 evaluable patients without CR, six are alive without regrowth of the disease (14-59 months, median: 39 months). Thus, these novel conditioning regimens allowed us to increase the dose intensity to nearly the maximum for each drug and seemed to reduce adverse effects compared to previously reported regimens with these drugs. With regard to the effect on outcome, the results of this study seem to be encouraging, but a further study on a larger number of patients is required.

Adolescent↗
PubMed1998

Depressive disorders as psychiatric complications after obesity surgery.

Three case reports of morbidly obese patients (two women and a man) who underwent vertical banded gastroplasty and who subsequently fell into depression, are presented here. The psychiatric diagnosis according to DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised), the eating pattern before obesity surgery, the past history of mental disorder, social adaptation before surgery, psychological gain from their obese state, and the presence of unrealistic expectations of obesity surgery were investigated. Case 1 was diagnosed postoperatively as having a major depressive episode without a personality disorder. Case 2 was diagnosed post-operatively as having a major depressive episode. Case 3 had a depressive disorder not otherwise specified. Cases 2 and 3 had a social phobia with comorbidity of personality disorders. Binge eating disorder was confirmed in all patients before obesity surgery. There were differences between case 1 and cases 2 and 3 based on the presence of personality disorder and the time of onset of depression. When some psychiatric characteristics are confirmed in obese patients, obesity surgery should be undertaken more prudently because the patients may manifest depression postoperatively. The pre-operative psychiatric assessment is essential for a decision on indication of obesity surgery.

Adult↗
PubMed1998

Dysembryoplastic neuroepithelial tumor in the insular cortex. Three dimensional magnetoencephalographic localization of epileptic discharges.

A case of dysembryoplastic neuroepithelial tumor in the left insular cortex manifesting with intractable seizures is presented. The multichannel magnetoencephalography (MEG) localized equivalent current dipoles of epileptic discharges at the cerebral cortex adjacent to the tumor. The total removal of the tumor resulted in complete disappearance of seizures. This case demonstrated that multichannel MEG was useful in the three-dimensional localization of irritative zone in the concealed cortices such as inside the sylvian fissure.

Brain Neoplasms↗
PubMed1998

Prognosis of advanced pancreatic cancer patients with reference to calorie intake.

Progressive weight loss and nutritional deterioration are commonly found in patients with advanced pancreatic cancer. There have been few studies of whether nutritional support improves survival for these patients. We retrospectively investigated the relationship between calorie intake and survival in 50 patients who died from cancer. The survival period was calculated from the day when their serum albumin level measured < 3.0 mg/dl. Total calorie intake was calculated on the basis of diet and parenteral nutrition for the week before the day when serum albumin levels fell to < 3.0 mg/dl. Patients were divided into a low- and a high-calorie intake group using the median of calorie intake per predictive basal metabolism. The survival period was significantly longer for the high- than for the low-calorie intake group (median 50 vs. 32 days, p = 0.02). We also investigated the relationships between calories of parenteral nutrition and survival. High-calorie parenteral nutrition subgroups tended to survive longer than low-calorie parenteral nutrition subgroups irrespective of enteral nutrition. Sufficient calorie intake may have the potential to prolong survival for patients with advanced pancreatic cancer.

Adult↗
PubMed1998

Monitoring of human cytomegalovirus infections in pediatric bone marrow transplant recipients by nucleic acid sequence-based amplification.

In the diagnosis of human cytomegalovirus (HCMV) infection, it is very important to distinguish symptomatic from asymptomatic infection. The nucleic acid sequence-based amplification (NASBA) technique was compared with single and nested polymerase chainreaction (PCR) methods. For NASBA detection, the beta2.7 transcript was chosen as a target because of its abundant active HCMV-specific expression. Of 20 pediatric bone marrow transplant (BMT) recipients, 8 developed HCMV-related clinical symptoms. The clinical sensitivities and specificities were 50% and 100% for single PCR, 100% and 67% for nested PCR, and 100% and 83% for NASBA, respectively. Follow-up of HCMV infections in pediatric BMT recipients showed that NASBA could both detect viral transcript prior to the onset of clinical symptoms and reflect clinical improvement due to antiviral therapy. These data suggest that NASBA should be useful for both predicting HCMV disease development and monitoring the effect of antiviral therapy.

Adolescent↗
PubMed1998

Sex differences in oxidative damage in ddY mouse kidney treated with a renal carcinogen, iron nitrilotriacetate.

Iron-induced free radical injuries in male and female ddY mice, especially the sex difference and its mechanisms, were studied after an i.p. injection of a renal carcinogen, ferric nitrilotriacetate. Male mice were much more susceptible to iron-induced free radical injuries than female mice. Oxidative modification of proteins and DNA occurred more strongly in males than in females, as measured by protein carbonyl content and 8-hydroxydeoxyguanosine, respectively. Histochemical detection of 4-hydroxy-2-nonenal-modified proteins using an antibody and DNA fragmentation as detected by the TUNEL method also showed that males are more severely damaged than females, especially in the proximal convoluted tubules. These results could not be explained by the difference in iron status between male and female mice. In fact, the toxic so-called 'free' iron in serum and kidney were not different between male and female mice and storage iron, such as ferritin and hemosiderin, was also comparable in both kidneys. In previous studies we proposed the glutathione cycling hypothesis to explain the sex differences. The half-life of glutathione in the kidney was significantly shorter in males (29 min) than in females (57 min), as determined by the glutathione decrease after buthionine sulfoximine treatment, a specific inhibitor of glutathione synthesis. The specific activity of gamma-glutamyltranspeptidase (EC 2.3.2.2) in female mice was 73% of that in male mice. These results suggest that the faster glutathione turnover in males could account for the higher susceptibility to oxidative injury by supplying the reducing equivalent that reduces Fe(III) to Fe(II), thereby facilitating iron-catalyzed free radical reactions.

Animals↗
PubMed1998

Elevated serum interleukin-6 levels in patients with pancreatic cancer.

The vast majority of pancreatic cancer patients have advanced disease at the time of diagnosis and they eventually become so emaciated that death primarily occurs from cancer cachexia. Cancer cachexia may be mediated by certain cytokines such as interleukin-6. In this study, we measured serum interleukin-6 levels in 55 patients with histologically proven pancreatic cancer and investigated their relationships to the clinical status of pancreatic cancer. A control population of 20 normal healthy adults and 25 chronic pancreatitis patients with comparable gender and age distribution characteristics was also studied. Serum interleukin-6 levels were measured using a quantitative sandwich enzyme-linked immunosorbent assay. Thirty pancreatic cancer patients (54.5%) had detectable levels, although interleukin-6 levels were detectable in only one healthy control and in two chronic pancreatitis patients. The specificity of serum interleukin-6 in this population was 93.3%, resulting in high diagnostic accuracy (72.0%). Among the pancreatic cancer patients, the detection rates of serum interleukin-6 levels increased significantly with the disease extent (p < 0.01). Moreover, a significant difference was also found in the detection rates between the 30 pancreatic cancer patients with body weight loss (76.7%) and the remaining 25 patients without weight loss (28.0%, p < 0.01). These results may provide new insight into both diagnosis and treatment of pancreatic cancer, because the diagnostic accuracy of serum interleukin-6 was high and because anti-interleukin-6 therapeutics could improve symptoms in pancreatic cancer patients with high interleukin-6 levels.

Adult↗
PubMed1998

Undifferentiated carcinoma of the liver with neuroendocrine features: a case report.

Undifferentiated carcinoma of the liver is very rare. A 54-year-old man was admitted to our hospital for a detailed examination of multiple liver tumors. These tumors were high or low echoic on ultrasonography, but not enhanced by contrast medium in dynamic computed tomography. A fine-needle aspiration biopsy specimen of the tumor showed undifferentiated carcinoma. The serum level of neuron-specific enolase was high (357 ng/ml) and the immunohistochemical stain of the biopsy specimen was positive for synaptophysin. We diagnosed the patient as having undifferentiated carcinoma of the liver with neuroendocrine features. The patient was treated with combined systemic chemotherapy: etoposide 100 mg/m2/day for three days plus cisplatin 80 mg/m2/day on day one. He achieved a partial response, the duration of which was 7+ months. The serum neuron-specific enolase levels were decreased to the normal range after chemotherapy. Primary liver carcinoma with neuroendocrine features is extremely rare, but in a suspicious case it is important to measure the serum levels of neuroendocrine markers and make a histological confirmation, because chemotherapy may be effective for this disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Pancreatic cancer: medical aspects.

Although pancreatic cancer (PC) continues to be a formidable disease, numerous treatment strategies are evolving that we hope will result in improved patient survival. To prolong the survival of patients with PC, it is essential to detect PC at the earliest stage possible and to develop effective nonsurgical treatments for this disease. The current strategies for the early diagnosis of PC include the development of diagnostic modalities and screening programs for the early detection of PC and the determination of high-risk groups for PC. K-ras mutations in pancreatic juice obtained endoscopically have been studied recently in association with the early diagnosis of PC, although the interpretation of the presence of a mutated K-ras gene requires caution. The role of the current nonsurgical treatments for PC has been limited. Identification of an effective new chemotherapeutic agent is a high priority, and the enrollment of patients with PC with metastatic disease into well-designed clinical trials is essential. New targets for therapy based on the understanding of the molecular biology of PC may provide avenues for future trials. We must continue to search actively for more accurate methods of diagnosis and more effective methods of treatment for PC.

Genes, ras↗
PubMed1998

Follow-up study of hypervariable region sequences of the hepatitis C virus (HCV) genome in an infant with delayed anti-HCV antibody responses.

An infant born prematurely and infected with hepatitis C virus (HCV) one month after birth was followed for 4.5 years. The patient did not produce detectable anti-HCV antibodies until two years after the onset of hepatitis. Before seroconversion, a single clone of HCV, as determined by quasispecies of the hypervariable region (HVR) of the HCV genome, was almost exclusively found in the serum. After seroconversion, however, another distinct lineage of HCV clones replaced it within half a year. As HCV infection persisted further in the presence of anti-HCV antibodies, many derivatives of both sequence lineages emerged to exhibit the typical quasispecies feature of HVR sequences. Neither seroconversion nor the changes in HVR sequences influenced the serum aminotransferase titers.

Aging↗