Biomedical subjects

S Oda

Publications and source records attributed to S Oda.

At least 37 records · Page 2Linked to original sources

PubMed2001

The instability within: problems in current analyses of microsatellite instability.

Microsatellite instability is regarded as one of the phenotypes of defective DNA mismatch repair and, consequently, as a marker of high risk for cancer. Despite numerous studies, the reported rates for positive microsatellite instability differ widely in each human malignancy. These discrepancies may relate to problems in the methods used. To establish a methodology for an accurate microsatellite instability analysis, technical requirements for a precise assay and biological conditions required for positive microsatellite instability were discussed. First, to describe microsatellite changes in detail, a sensitive detection system with linear detection characteristics and electrophoresis with standardised migration and minimised migration errors are considered to be necessary. Therefore, systems using fluorescent labelling and laser scanning are recommended. For reproducible polymerase chain reactions, it is essential to control the terminal deoxynucleotidyl transferase activity in Taq polymerase. Second, as a biological condition for positive microsatellite instability, feasible selection and combination of microsatellite markers, mutations in specific DNA mismatch repair genes and existence of monoclonal populations enriched sufficiently in a sample are essential. Finally, one possible diagnostic criterion for positive microsatellite instability is proposed, that is the existence of one of the patterns shown in the panel (see Fig. 6) at one or more loci in a set of more than five microsatellite markers.

DNA Repair↗

PubMed2001

Intravenous immunoglobulin therapy for Guillain-Barré syndrome with IgG anti-GM1 antibody.

To compare the effects of intravenous immunoglobulin (IVIg) therapy and plasmapheresis for the IgG anti-GM1-positive subtype of Guillain-Barré syndrome (GBS), clinical and electrophysiological recoveries were analyzed in 24 patients treated with IVIg (n = 10) or plasmapheresis (n = 14). At entry, there were no significant differences between the two patient groups in age, sex, clinical severity (Hughes grade), sum scores of distally evoked amplitudes of compound muscle action potentials (CMAPs), and frequency of Campylobacter jejuni infection. The patients treated with IVIg had significantly lower Hughes grade scores 1, 3, and 6 months after onset (P = 0.03), and a higher probability to regain independent locomotion at 6 months [P(logrank) = 0.044]. In the IVIg group, markedly rapid recovery (improvement by two or more Hughes grade scores within 4 weeks) was more frequent (6 of 10 vs. 3 of 14, P = 0. 03), and delayed recovery (unable to walk independently at 6 months) was less frequent (0 of 10 vs. 4 of 14, P = 0.06). CMAP sum score at 6 months tended to be greater for the IVIg group (P = 0.07). For the IgG anti-GM1-positive subgroup of GBS patients, IVIg therapy may be a more efficacious treatment than plasmapheresis.

Action Potentials↗

PubMed2001

Phylogenetic position of Eulipotyphla inferred from the cDNA sequences of pepsinogens A and C.

Although to date the phylogenetic position of the provisional order Eulipotyphla has been assessed by various molecular markers, it has not been conclusively clarified due to low statistical supporting values and inconsistent results. To clarify the phylogenetic position of Eulipotyphla, we cloned cDNAs for pepsinogens A and C from five mammalian species belonging to four different orders and determined their nucleotide sequences. Molecular phylogenetic analysis based on the 1st and 2nd codon positions of the protein-coding region of cDNA sequences strongly supported the close relationship between Eulipotyphla and Chiroptera. Carnivora was found to be a sister group to these two orders. The monophyly of the order Rodentia and that of the cohort Glires (Rodentia and Lagomorpha) was also shown by the present phylogenetic trees of pepsinogens.

Amino Acid Sequence↗

PubMed2001

Prognostic value of p53 protein expression in breast cancer; an immunohistochemical analysis of frozen sections in 514 Japanese women.

BACKGROUND: Although the prognostic value of p53 protein has been extensively studied in breast cancer, there have so far been few immunohistochemical studies of p53 protein using frozen sections in a large series of Japanese women with breast cancer. PATIENTS AND METHODS: Immunohistochemical staining for p53 protein was performed on frozen sections from 514 Japanese patients with breast cancer with a mean follow-up duration of 31 months. RESULTS: Two hundred and eight (40.5%) of 514 cases showed nuclear accumulation of p53 protein. There was a significant inverse correlation between p53 protein and estrogen receptor (ER) status. The patients who were positive for p53 protein had a significantly worse outcome in terms of both disease free survival (DFS) (p<0.0001) and overall survival (OS) (p=0.0411) than those negative for p53 protein. The same effect on DFS was seen in subgroups divided either by nodal status or ER status. Multivariate analyses indicated that nodal status, ER and p53 protein were all independent prognostic factors for DFS. The nodal status, ER and tumor size were independent prognostic factors for OS, and p53 protein status was still an independent prognostic factor for DFS in subgroups divided either by nodal status or ER status. CONCLUSION: Our findings demonstrated the prognostic value of p53 protein expression for the early recurrence of breast cancer, and the prognostic value of p53 protein expression was independent from that of both the nodal status and ER status in breast cancer.

Adult↗

PubMed2001

Prognostic value of DNA ploidy in 653 Japanese women with node-negative breast cancer.

BACKGROUND: The prognostic value of DNA ploidy has been extensively studied in breast cancer; however, the results remain controversial. Flow cytometry (FCM) studies of DNA ploidy on frozen sections have not yet been performed in a large series of Japanese women with node-negative breast cancer. METHODS: An FCM analysis of DNA ploidy was performed on frozen sections of node-negative breast cancer from 653 Japanese women, with a mean follow-up duration of 46 months. RESULTS: Three hundred and twenty-four (49.6%) patients showed a diploid tumor, while 329 (50.4%) showed an aneuploid tumor. There was a significant correlation between DNA ploidy and estrogen receptor (ER) status. Patients with an aneuploid tumor had a significantly worse outcome in terms of both disease-free survival (DFS; P = 0.0116) and overall survival (OS: P = 0.0492) than those with a diploid tumor, while the same effect, in terms of DFS, was also seen in ER-positive breast cancer. Multivariate analyses indicated DNA ploidy to be an independent prognostic factor for DFS, while DNA ploidy and tumor size were found to be independent prognostic factors for OS. DNA ploidy was also shown to be an independent prognostic factor for DFS in ER-positive breast cancer. CONCLUSION: Our findings demonstrated DNA ploidy, based on FCM, to have an important prognostic value in Japanese women with node-negative breast cancer.

Adult↗

PubMed2001

MRimaging findings after ventricular puncture in patients with SAH.

OBJECT: Using magnetic resonance (MR) imaging, we studied brain injury from ventricular puncture performed during craniotomy in the acute stage of subarachnoid hemorrhage (SAH). METHODS: 80 patients underwent craniotomy for aneurysm obliteration within 48 hr after SAH, ventricular puncture for drainage of cerebrospinal fluid (CSF) was performed to reduce intracranial pressure. MR imaging was performed within 3 days following surgery to measure the size of the lesion, and was repeated on postoperative days 14 and 30. CONCLUSIONS: Of the 80 patients with ventricular puncture preceding craniotomy, 65 (81%) showed MR evidence of brain injury from the puncture. Overall, 149 lesions were detected. According to coronal images, cortical injuries (54 cases), penetrating injury to tracts along the ventricular tube (55 cases), caudate injury (25 cases), and corpus callosum injury (15 cases). Brain injuries from ventricular puncture did not correlate significantly to patient outcome. While ventricular puncture and drainage of CSF can readily be performed to decrease brain volume at the time of craniotomy in acute-stage SAH, neurosurgeons should be aware of a surprisingly high incidence of brain injury complicating puncture.

Acute Disease↗

PubMed2001

Mechanisms underlying increased release of endothelin-1 from aorta in diabetic rats.

To clarify the mechanism underlying increased endothelin-1 release in diabetic rats, we examined its release from thoracic aortas obtained from streptozotocin-induced diabetic rats. The methoxamine-induced contraction was significantly inhibited by BQ-123 plus BQ-788 (specific antagonists for ET(A) and ET(B) receptors) in diabetic, but not control rats. Preincubation with phosphoramidon also inhibited the methoxamine-induced contraction in diabetic but not control rats. The expression of prepro endothelin-1 mRNA was significantly enhanced in aortas from streptozotocin-induced diabetic rats. These results suggest that the increases in the basal and alpha-agonist-induced release of endothelin-1 in the diabetic state may be due to an overexpression of the mRNA for prepro endothelin-1.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed2001

Neuromuscular fatigue during maximal concurrent hand grip and elbow flexion or extension.

The objective was to investigate muscle fatigue measuring changes in force output and force tremor and electromyographic activity (EMG) during two sustained maximal isometric contractions for 60s: (1) concurrent hand grip and elbow flexion (HG and EF); or (2) hand grip and elbow extension (HG and EE). Each force tremor amplitude was decomposed into four frequency bands (1-3, 4-10, 11-20, and 21-50Hz). Surface EMGs were recorded from the flexor digitorum superficialis (FDS), extensor digitorum (ED), biceps brachii (BB) and lateral head of triceps brachii (TB). The HG and EF forces for the HG and EF and the HG force for the HG and EE declined rapidly, whereas the EE force remained almost constant near to the initial value for the first 40s and then declined. The decrease in EMG amplitude was observed not for the FDS muscle but for the ED muscle. The HG tremor amplitude for each frequency band showed similar decreasing rate, whereas the decreases in EF and EE tremor amplitudes for the lower band (below 10Hz) were slower than those for the higher band (above 11Hz). The neuromuscular mechanisms underlying muscle fatigue during sustained maximal concurrent contractions of hand grip and elbow flexion or extension are discussed.

Adult↗

PubMed2001

The effects of recreational underwater exercise in early evening on sleep for physically untrained male subjects.

The present study investigated the effects of recreational underwater exercise (UWE; 28.9-31.5 degrees C, 16:00-16:50, 36.2 +/- 5.2 %HRres) on thermal response and nocturnal sleep. Rectal temperature (Trec) and sleep parameters of eight physically untrained male subjects were measured in both non-exercise (NE) and UWE days. Underwater exercise consisted of aerobic exercises with various kinds of movements. During UWE, Trec raised slightly in most subjects, but declined in one subject. We could not observe a rapid decline in Trec before sleep on a UWE day. The polysomnographic and subjective sleep parameters showed no significant differences between NE and UWE nights. The quality of sleep did not improve on the night when UWE was performed, and thermal changes might be related to the results.

Adult↗

PubMed2001

Current topics on cytokine removal technologies.

It has been widely accepted that cytokines play important roles in the development of organ failure in various pathophysiological conditions of critically ill patients. Various new technologies, including continuous renal replacement therapy, have been developed for the removal of causative humoral mediators in sepsis or other critical conditions. Nonselective blood purification technologies, such as hemofiltration and plasma exchange, are applied in cytokine removal technology. However, the more selective blood purification technologies, such as adsorption, and the combination of those technologies, should be considered in future applications. Only through a prospective randomized controlled study can it be elucidated whether or not these technologies have efficacy in the treatment of sepsis and critically ill patients with hypercytokinemia. We should join and discuss the design of future clinical trials with a standardized strategy for the evaluation of the technologies.

Adsorption↗

PubMed2001

Analysis of Mn(2+)/Ca(2+) influx and release during Ca(2+) oscillations in mouse eggs injected with sperm extract.

Repetitive Ca(2+) release from the endoplasmic reticulum (ER) is necessary for activation of mammalian eggs. Influx and release of Mn(2+) and Ca(2+) during Ca(2+) oscillations induced by injection of sperm extract (SE) into mouse eggs were investigated by Mn(2+)-quenching of intracellular Fura-2 after adding Mn(2+) to external medium. Mn(2+)/Ca(2+) influx was detected at the resting state. A marked Mn(2+)/Ca(2+) influx occurred during the first Ca(2+) release upon SE injection, and persistently facilitated Mn(2+)/Ca(2+) influx was observed during steady Ca(2+) oscillations. As intracellular Mn(2+) concentration ([Mn(2+)](i)) increased progressively, periodic [Mn(2+)](i) rises appeared, corresponding to each Ca(2+)transient but taking a slower time course. A numerical simulation based on continuous Mn(2+)/Ca(2+) influx-extrusion across the plasma membrane and release-uptake across the ER membrane in a competitive manner mimicked well the Mn(2+) oscillations calculated from experimental data, strongly suggesting that repetitive Mn(2+) release develops after Mn(2+) entry and uptake into the ER. In other experiments, a marked Mn(2+) influx occurred upon Mn(2+) addition to Ca(2+)-free medium after depletion of the ER using an ER Ca(2+) pump inhibitor plus repeated injection of inositol 1,4,5-trisphosphate (InsP(3)). No significant increase in Mn(2+) influx was induced by injection of SE, InsP(3), or Ca(2+), when Ca(2+) release was prevented by pre-injection of an antibody against the InsP(3) receptor. We concluded that Ca(2+) influx is activated during the initial large Ca(2+)release possibly by a capacitative mechanism and kept facilitated during steady Ca(2+) oscillations. The finding that repetitive Mn(2+) release is caused by continuous Mn(2+) entry suggests that continuous Ca(2+) influx may play a critical role in refilling the ER and, thereby, maintaining Ca(2+)oscillations in mammalian fertilization.

Animals↗

PubMed2001

Preoperative evaluation of submucosal invasive colorectal cancer using a 15-MHz ultrasound miniprobe.

BACKGROUND AND STUDY AIMS: Recently, it was reported that focal submucosal invasive colorectal cancer could be treated by polypectomy or endoscopic mucosal resection (EMR) because of the rarity of lymph-node metastasis. Our objective was to examine the accuracy and efficacy of a 15-MHz ultrasound miniprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer. PATIENTS AND METHODS: A total of 35 patients with submucosal invasive colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings in resected specimens. RESULTS: Although the accuracy of the miniprobe in categorizing submucosal invasion into three subclasses (SM1, invasion limited to the upper third; SM2, limited to the middle third; SM3, limited to the lower third) was low (37.1%; 13/35), the accuracy in differentiation between < or = SMI (M and SMI) and > or = SM2 (SM2, SM3, MP, and S) was 85.7 % (30/35). CONCLUSIONS: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.

Adult↗

PubMed2001

Expression of a green fluorescent protein variant in mouse oocytes by injection of RNA with an added long poly(A) tail.

In oocytes, cytoplasmic 3' polyadenylation regulates translational activation of dormant mRNA during meiotic maturation. Thus exogenous proteins are hardly expressed after injection of conventional RNA. To circumvent this, we synthesized a long polyadenylated (approximately 250 A) tail to encode RNA with an enhanced yellow fluorescent protein targeted to mitochondria (EYFP-mito), and injected it into mouse oocytes at the germinal vesicle (GV) stage. From this transcript, EYFP-mito was clearly expressed in approximately 80% of oocytes, while scarce expression from a transcript with only 30 A was observed. In strongly expressing oocytes, fluorescence was detected within 1-3 h after RNA injection, increased linearly up to 12 h, and reached a maximum at 12-15 h. The distribution of EYFP-mito matched the staining of mitochondria in these oocytes. About 80% of these oocytes underwent GV breakdown and 60% matured in vitro, comparable to non-expressing or non-RNA-injected oocytes. Some of the oocytes which strongly expressed EYFP-mito remained at the GV stage. Thus, the expression was not always accompanied by meiotic maturation, nor did it suppress the maturation process. Mature oocytes expressing EYFP-mito possessed normal fertilizability associated with intracellular Ca(2+) oscillations, and developed into 2-cell embryos. Thus, polyadenylated RNA is a useful tool applicable to the expression of EYFP-fused functional proteins or of indicator protein probes for studies of mammalian fertilization.

Animals↗

PubMed2001

Activity of a sperm-borne oocyte-activating factor in spermatozoa and spermatogenic cells from cynomolgus monkeys and its localization after oocyte activation.

It is widely accepted that mature mammalian oocytes are induced to resume meiosis by a sperm-borne oocyte-activating factor(s) (sperm factor, SF) immediately after normal fertilization or intracytoplasmic sperm injection. The SF is most likely a soluble factor that is localized within the cytoplasm of mature spermatozoa, but the exact stage at which it appears during spermatogenesis and its localization after oocyte activation is not fully understood, except in the mouse. First, we injected mature spermatozoa and spermatogenic cells from cynomolgus monkeys into mouse oocytes to assess their oocyte-activating capacity. More than 90% of mouse oocytes were activated after injection of monkey spermatozoa. Round spermatids and primary spermatocytes (late pachytene to diplotene) also activated oocytes (93% and 79%, respectively). Injection of monkey spermatozoa and spermatids induces intracellular Ca(2+) oscillations in a pattern similar to that seen following normal fertilization. Most spermatocytes did not produce typical intracellular Ca(2+) oscillations. Second, we transferred pronuclei or cytoplasts from mouse oocytes that had been activated by monkey spermatozoa or spermatids into intact mature mouse oocytes by electrofusion in order to examine the localization of the SF after pronuclear formation. Some of the SF was localized within the pronuclei, but some stayed in the ooplasm. This study demonstrated that spermatogenic cells of cynomolgus monkeys acquire oocyte-activating capacity at much earlier stages than those of mice, and that the monkey SF has a pronucleus-directing nature, although to a lesser extent than the mouse SF.

Animals↗

PubMed2001

Usefulness of plasma exchange plus continuous hemodiafiltration to reduce adverse effects associated with plasma exchange in patients with acute liver failure.

OBJECTIVE: To efficiently remove middle-molecular-weight substances such as hepatic toxins and minimize adverse effects associated with plasma exchange implementation, we have performed plasma exchange slowly in combination with continuous hemodiafiltration. This study was designed to determine the usefulness of plasma exchange with continuous hemodiafiltration in reducing the adverse effects associated with implementation of plasma exchange alone. DESIGN: A retrospective clinical study. SETTING: University teaching hospital. PATIENTS: The study involved 90 patients with liver failure who had been treated with plasma exchange in our department over the past 12 yrs. We examined these patients by dividing them into two groups (48 patients treated with plasma exchange alone and 42 patients treated with plasma exchange plus continuous hemodiafiltration at the time of plasma exchange implementation). MEASUREMENTS AND MAIN RESULTS: Baseline blood Na+ concentration, HCO3- concentration, and colloid osmotic pressure were followed after implementation of plasma exchange to compare the frequency of development of three adverse effects (hypernatremia, metabolic alkalosis, and sharp decrease in colloid osmotic pressure) in the two groups. Hypernatremia was found in 26.7% of treatments in the group with plasma exchange alone and 3.3% in the group of plasma exchange plus continuous hemodiafiltration, and metabolic alkalosis was found in 30.6% of treatments in the group with plasma exchange alone and 4.9% in the group of plasma exchange plus continuous hemodiafiltration; both percentages were significantly higher in the group with plasma exchange alone (p <.001). A sharp decrease in colloid osmotic pressure occurred in 13.3% of treatments in the group with plasma exchange alone but was not observed at all in the patients treated with plasma exchange plus continuous hemodiafiltration. CONCLUSIONS: We conclude that adverse effects associated with plasma exchange for artificial liver support for liver failure can be alleviated with use of plasma exchange plus continuous hemodiafiltration instead of plasma exchange alone.

Adolescent↗

PubMed2001

Asymptomatic versus symptomatic infarcts from vasospasm in patients with subarachnoid hemorrhage: serial magnetic resonance imaging.

OBJECTIVE: By use of serial magnetic resonance imaging (MRI), we prospectively investigated the incidence of and the risk factors associated with infarction caused by vasospasm with or without a delayed ischemic neurological deficit (DIND) in patients with subarachnoid hemorrhage (SAH). METHODS: In 125 patients who underwent surgery for early aneurysms, postoperative MRI scans were obtained at four time points. We defined an infarct from vasospasm as a new lesion not present on the initial MRI within 3 days after SAH and therefore not attributable to primary brain damage or surgical complications. RESULTS: Overall, symptoms of infarction (i.e., DIND) occurred in 38% of patients (48 of 125); DIND with a new infarct on MRI was evident in 34% (43 patients), whereas 4% (5 patients) showed no new lesion but had a DIND. However, 29 patients (23%) showed a new infarct but no DIND on MRI studies (asymptomatic infarction). Asymptomatic ischemic lesions due to vasospasm tended to involve noneloquent brain areas in the territory of intraparenchymal perforators. Multivariate analysis identified variables associated with symptomatic infarction to be of poor SAH grade, advanced age of the patient, angiographic findings of vasospasm, multiple cortical infarcts on MRI studies consistent with vasospasm, and chronic hydrocephalus. CONCLUSION: Analysis of the data confirmed the occurrence of asymptomatic infarcts due to vasospasm. These infarcts often developed in noneloquent areas representing perforator territory. MRI investigation of vasospastic lesions referable to intraparenchymal vessels such as perforators complements the study of extraparenchymal major vessel vasospasm in patients with SAH by computed tomographic angiography.

Adult↗

PubMed2001

Tumor growth patterns and biological characteristics of early gastric carcinoma.

Gastric cancer is a major malignant disease. The development of new diagnostic techniques and mass screening have led to increased detection rates of patients with early-stage gastric cancer in Japan. However, after curative resection of early gastric cancer, there are various types of recurrences, and residual occult disease and distant micrometastasis precede death. The growth and metastatic potential of cancer cells are closely related to the postoperative outcome, and patients at risk for cancer-related death after surgery have to be closely monitored to prevent tumor recurrence. The biological behavior of cancer cells should be determined in patients with early gastric cancer and with a less favorable prognosis to detect potential early recurrences in the liver. Two types of growth patterns have been found in early gastric cancer: the superficially spreading (Super) type and the penetrating (Pen) type, and the clinicopathological and biological characteristics of each type have been extensively determined. A subtype of the Pen-type gastric cancer, which is progressing expansively with complete destruction of the muscularis mucosae (Pen A type) has a less favorable prognosis due to early recurrences in the liver. These clinical cancer types are closely related to chromosomal instability in DNA aneuploidy and p53 overexpression, and vascular endothelial growth factor activation induced tumor angiogenesis, vascular invasion and hematogenous metastasis. Thus, patients with Pen-A-type cancer showing expansive tumor growth had a poorer postoperative outcome and a hematogenous-related recurrence of the cancer. Antiangiogenic approaches in a postoperative setting may prove to be effective in preventing tumor recurrence and improving the prognosis for these patients.

Adenocarcinoma↗

PubMed2001

Features of microsatellite instability in colorectal cancer: comparison between colon and rectum.

In one third of colorectal cancer patients, tumours occur in the rectum. Unique aetiologies may underlie the increased carcinogenesis in this region of the colorectum. Microsatellite instability (MSI) was analysed in specimens obtained from 121 colorectal carcinoma patients, using five dinucleotide markers and a new fluorescent system. The incidence of microsatellite alterations in the proximal colon, the distal colon and the rectum was 44.4% (16/36), 37.2% (16/43) and 23.8% (10/42), respectively. Patterns of microsatellite alterations could be classified into two subtypes, one showing relatively small changes within 6 bases (type A) and the other exhibiting drastic changes over 8 bases (type B). All the changes observed in tumours in the rectum were type A, and no type B mutation was noted. There was a close correlation between type B mutations and high-frequency MSI (> or =2 markers), MSI-H, and between type A mutations and low-frequency MSI (1 marker), MSI-L. The type B/MSI-H phenotype significantly correlated with the proximal localisation of tumours. In the rectum, there was no tumour with the type B/MSI-H phenotype. These findings suggest that cancers occurring in the colon and the rectum have a differential molecular background for carcinogenesis.

Adenocarcinoma↗