Biomedical subjects

S Oda

Publications and source records attributed to S Oda.

At least 37 records · Page 2Linked to original sources

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↗

PubMed2001

Coupling of fermentation and esterification: microbial esterification of decanoic acid with ethanol produced via fermentation.

Two different kinds of bioprocess, ethanol fermentation and subsequent microbial esterification, were coupled using Issatchenkia terricola IFO 0933 in an interface bioreactor. The strain produced ethyl decanoate (Et-DA) by esterification of exogenous decanoic acid (DA) with ethanol produced via fermentation. The efficiency of the new coupling system depended on the concentration of glucose in a carrier and DA in an organic phase (decane) in an agar plate interface bioreactor. Optimum glucose content and DA concentration were 4% and 29 mM, respectively.

Decanoic Acids↗

PubMed2001

A new double coupling system: synthesis of citronellyl acetate via transacetylation to citronellol from acetyl coenzyme A produced from glucose and free fatty acids.

A double coupling system, which couples metabolism of glucose and transacetylation, is a unique procedure for the production of acetic esters. In the novel coupling system described in this article, acetyl coenzyme A (acetyl-CoA) was supplied via metabolism of both glucose and exogenous saturated fatty acids. While short and middle chain fatty acids having C4-8 were very biotoxic, myristic acid (C14) was effectively used as a source of acetyl-CoA.

Acetyl Coenzyme A↗

PubMed2001

A case of aldosterone-producing adrenocortical adenoma associated with preclinical Cushing's syndrome and hypersecretion of parathyroid hormone.

A rare case of aldosterone-producing adrenocortical adenoma with preclinical Cushing's syndrome and hypersecretion of parathyroid hormone (PTH) is described. A 64-year-old male patient had a history of hypertension for two decades and hypokalemia for 4 years. He suffered from left hemiparesis and aphasia due to cerebral hemorrhage, but his appearance was not Cushingoid. His plasma renin activity was below the normal range, while plasma aldosterone concentration was high. They did not respond to furosemide-upright test. His plasma cortisol level in the morning was at the upper limit of the normal range, but it did not show a diurnal rhythm nor was it suppressed by 1 mg and 8 mg of dexamethasone. Computed tomography showed a low density tumor in the right adrenal gland. An adrenal scintigram under dexamethasone treatment revealed an uptake of the tracer on the right side, and plasma aldosterone and cortisol concentrations in the adrenal vein were higher on the right side than on the opposite. The diagnosis of right aldosterone-producing adrenal adenoma with an autonomous production of cortisol was confirmed by right adrenalectomy. Histological findings showed an adenoma consisting mostly of clear cells, but that the nests of compact cells were scattered. Analysis of an extract from the adenoma revealed that the adenoma contained an excess amount of aldosterone and that the cortisol/corticosterone ratio was higher than that of aldosterone-producing adenoma. Both serum calcium and PTH levels remained high one year after adrenalectomy. Ultrasonography revealed the swelling of a parathyroid gland on the left side, indicating the coexistence of an autonomous hyperparathyroidism.

Adenoma↗

PubMed2001

Histological characteristics of the pelage skin of rough fur mice (C3H/HeJ- ruf/ruf).

Pelage skin of C3H/HeJ mice homozygous at an autosomal recessive mutant locus, rough fur (ruf) which is located on chromosome 9, was histologically analyzed. Sebaceous glands synthesizing lipids were larger in the mutant mice than in controls in an examination by Sudan IV staining. Electron microscopic analysis of the sebaceous gland showed that lipid droplets were denser in mutant mice than in control mice, and that they were irregular in shape in ruf mice while those of controls were round. Our results suggested that rough fur (ruf) mice might be an animal model for hyperlipogenesis of the pelage skin.

Animals↗

PubMed2001

A new mouse model with cochleo-saccular type inner ear defects.

We found a new inner ear mutant exhibiting abnormal behavior, such as circling and head shaking, in a breeding stock of SJL/J mice. The traits are inherited in a simple autosomal-recessive fashion. Animals homozygous for the responsible gene, designated cosa, show no startle response to sounds and an inability to swim. In the inner ears of cosa/cosa homozygous, but not +/cosa heterozygous adults, histopathological features of severe damage that are typical for 'cochleo-saccular' or 'spotting' mutants have been demonstrated. We suggest here that the abnormal mice carry a mutation of a gene that is developmentally switched on in the early stages of development and is involved in endolymph homeostasis.

Animals↗

PubMed2001

Central and peripheral visual reaction time of soccer players and nonathletes.

Visual Reaction Time (RT) was measured by presenting three different sizes of stimulus to the central and peripheral fields of vision in 6 soccer players and 6 nonathletes. An electromyogram was recorded from the flexor digitorum superficialis muscle of the responding forearm. Peripheral visual RT was longer in comparison to central visual RT due to an increment in Premotor Time. The soccer players showed shorter Premotor Times during central and peripheral visual RT tasks than nonathletes, suggesting that the soccer players are better able to respond quickly to a stimulus presented to peripheral as well as central positions.

Adult↗

PubMed2001

Efficacy of the novel selective platelet-derived growth factor receptor antagonist CT52923 on cellular proliferation, migration, and suppression of neointima following vascular injury.

Exaggerated or inappropriate signaling by the platelet-derived growth factor receptor (PDGFR) tyrosine kinase has been implicated in a wide variety of diseases. Thus, a series of piperazinyl quinazoline compounds were identified as potent antagonists of the PDGFR by screening chemical libraries. An optimized analog, CT52923, was shown to be an ATP-competitive inhibitor that exhibited remarkable specificity when tested against other kinases, including all members of the closely related PDGFR family. The PDGFRs and stem cell factor receptor were inhibited with an IC(50) of 100 to 200 nM, while 45- to >200-fold higher concentrations of CT52923 were required to inhibit fms-like tyrosine kinase-3 and colony-stimulating factor-1 receptor, respectively. Other receptor tyrosine kinases, cytoplasmic tyrosine kinases, serine/threonine kinases, or members of the mitogen-activated protein kinase pathway were not significantly inhibited at 100- to 1000-fold higher concentrations. In addition, this compound also demonstrated specificity for inhibition of cellular responses. Platelet-derived growth factor-induced smooth muscle cell migration or fibroblast proliferation was found to be blocked by CT52923 with an IC(50) of 64 and 280 nM, respectively, whereas 50- to 100-fold higher concentrations were required to inhibit these responses when induced with fibroblast growth factor. To investigate the effect of CT52923 on PDGFR signaling, in vivo studies demonstrated that CT52923 could significantly inhibit neointima formation following carotid artery injury by oral administration in the rat. Therefore, PDGFR antagonism by CT52923 could be a viable strategy for the prevention of clinical restenosis or the treatment of other human diseases involving PDGFR signaling.

Angioplasty, Balloon↗

PubMed2001

[A study of the relation between providing healthcare information and behavior changes of people in Japan. Parental behavior changes after receiving information about the sudden infant death syndrome].

OBJECTIVE: Considering the lack of evidence concerning the relationship between providing healthcare information and behavior of people in Japan, we utilized a questionnaire to survey the parents of infants to evaluate behavior change after receiving information about the Sudden Infant Death Syndrome (SIDS). METHODS: A questionnaire about SIDS information was administered in 234 municipalities in Niigata, Gifu, Shizuoka, and Hiroshima Prefectures and in Yokohama City in November and December of 1999 to 14,879 parents who visited for the 18-month health examination of their children. The questionnaire did not ask for the participants' names. Logistic regression analysis was used to study the connection between behavior change and SIDS information sources. RESULTS: 10,900 parents returned the questionnaire to give a 73.3% response rate, 19.0% of these receiving information about SIDS risk factors from hospitals or clinics, 3.7% from public health centers, and 9.2% from their friends. More received information from the mass media such as TV programs, which provided the main source for 71.1% of the parents. The degree of behavior change was evaluated after adjustment for variables concerning a variety of information sources and other appropriate factors such as the age and sex of parents and the number of their children. We found that receiving information from hospitals or clinics significantly influences behavior changes for all kinds of risk factors. Information from public health centers, baby-care groups, and friends influenced behavior changes relevant to the risk factors for feeding methods, sleeping position, and parents' smoking. There was no relation between receiving information from the mass media and behavior change of parents. CONCLUSIONS: The mass media provide far more information than do medical facilities, public health centers, baby-care groups and personal contacts but the latter played much more effective roles in making parents change their baby care behavior. These results point to an obvious discrepancy between efficiency in providing information and the degree of behavior change elicited. We should thus take the source of information and the target population into consideration when we examine the best way to provide healthcare information for people in the future.

Adult↗

PubMed2000

NAD(P)+-NAD(P)H models. 90. Stereoselection controlled by electronic effect of a carbonyl group in oxidation of NAD(P)H analog.

4-Monodeuterated NAD(P)H model compounds (1,4,6,7-tetrahydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]az epin; 11Me-MMPAH) have been oxidized with a series of p-benzoquinone and its derivatives in the presence of Mg2+. The models have an axial chirality with respect to the orientation of carbonyl dipole, the dihedral angle of which is larger than 55 degrees out of the plane of dihydropyridine ring. Without Mg2+, the anti- (with respect to the carbonyl dipole) hydrogen is 3 to 32 times more reactive than the corresponding syn-hydrogen, whereas, when Mg2+ is present in the system, the selectivity is shifted toward the syn-preferency. Mg2+ plays the role of a Lewis acid catalyst to control the stereochemistry at the same time as it catalyzes the reaction.

Catalysis↗

PubMed2000

Synthesis and applications of [1-(15)N]-labeled 4,6-dimethyl-4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide as a useful tool for mechanistic investigations.

[1-(15)N]-Labeled 4,6-dimethyl-4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide (1-(15)N1) was easily prepared by nitration of commercially available 6-amino-1,3-dimethyl-1H-pyrimidine-2,4-dione using 15N-enriched nitric acid followed by an intramolecular oxidative cyclization with iodosylbenzene diacetate under mild conditions. On the basis of the experimental results using 1-(15)N1, the formation of 8-phenyltheophylline (3), the 1,3-dimethylalloxazines (4: n = 0, 1), and 1,3,7,9-tetramethyl-1H,9H-pyrimido[5,4-g]pteridine-2,4,6,8-tetraone++ + (5) in the thermal reaction of the N-oxide 1 with benzylamine, aniline, or piperidine, and the generation of NO or NO-related species in the reaction with N-acetylcysteamine were reasonably explained by considering the initial attack of the employed nucleophiles on the 3a-position of 1.

Aniline Compounds↗