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Biomedical subjects

R Saito

Publications and source records attributed to R Saito.

At least 127 records · Page 7Linked to original sources
PubMed1998

Recovery from complete atrioventricular block caused by idiopathic giant cell myocarditis after corticosteroid therapy.

Giant cell myocarditis (GCM) is a rapidly progressive disease that leads to ventricular tachycardia or high-grade atrioventricular (A-V) block, frequently requiring a pacemaker. A 64-year-old woman developed syncope as a result of idiopathic GCM with A-V block. She required both a temporary and a permanent pacemaker. Two-dimensional echocardiography showed severely reduced wall motion. There was no histologic or clinical evidence to suggest sarcoidosis. Despite treatment with diuretics and an angiotensin-converting enzyme inhibitor, exertional dyspnea persisted. She received prednisolone 4 months after the onset of complete A-V block in the late phase of GCM. Prednisolone improved A-V nodal conduction in spite of the fact that there was no influence from LV wall motion, and sinus rhythm has continued for more than 2 years. In this patient, prednisolone was effective in the treatment of GCM.

Anti-Inflammatory Agents↗
PubMed1998

[Effects of arginine-vasopressin on neuronal interaction from the area postrema to the nucleus tractus solitarii in rat brain slices].

The effects of vasopressin (AVP) on area postrema (AP) neurons and the neuronal connection between the AP and nucleus tractus solitarii (NTS) were investigated electrophysiologically in slices preparation of the medulla oblongata of rats. In the AP, 27.9% of 129 neurons were excited by AVP and 20.5% were inhibited. The excitation was blocked by a V1 receptor antagonist. Synaptic transmission of the AP to the NTS was mainly mediated by non-NMDA receptors. Local application of AVP to the AP activated the NTS neurons. This activation was blocked by an NMDA antagonist. These results suggest that the excitation originating in the AP is conveyed to the NTS via non-NMDA receptors and modified by NMDA receptor activation secondly. These processes may be important in regulation of the arterial baroreceptor reflex.

Animals↗
PubMed1998

[A clinical comparison of orthodox myringoplasty and a simple method with fibrin glue].

Orthodox myringoplasty was clinically compared with a simple method with fibrin glue which rapidly came into wide use after the report of Yuasa in 1989. In Okayama Saiseikai General Hospital, orthodox myringoplasty was performed in 109 ears from September 1988 to November 1995, and the simple method with fibrin glue was performed in 84 ears from May 1991 to November 1995. The results showed that 90.8% of all eardrum perforations treated by orthodox myringoplasty and 79.8% of all eardrum perforations treated by the simple fibrin glue method were successfully closed. The rate of closure with each method was low in patients with large perforations. Generally speaking the hearing prognosis with each method, hearing improvement was observed right after the operation, and the improved hearing became stable about six months later. The difference in hearing prognosis was investigated in patients with small or large perforations. In patients with large perforations, the improved hearing slightly worsened a year after treatment by orthodox myringoplasty. These results show that the simple method with fibrin glue had the advantage of good hearing prognosis over orthodox myringoplasty, while it was inferior in the rate of closure of large eardrum perforations. It was considered that a simple fibrin glue method should be devised to prevent reperforation and should be used for patients with large perforations.

Adolescent↗
PubMed1998

[Subcapsular hematoma of the liver after extracorporeal shock wave lithotripsy].

We experienced a case of a hepatic subcapsular hematoma after extracorporeal shock wave lithotripsy (ESWL) for a right renal stone. To our knowledge this presentation is the second case in the Japanese literature. A 63-year-old female with a right renal stone received 2,800 shots of 14.0 kilo-volts shockwave with Sonolith 3,000. Preoperative examination of the blood disclosed no abnormalities in the coagulating system except slight reduction of platelet count and slight impairment of liver function. Postoperative routine ultrasound echograms revealed a hepatic subcapsular hematoma although she had no symptom. The size of the hematoma measured 11.0 x 5.0 cm in computed tomograms (CT). She was carefully observed without any treatments because the hematoma did not increase in size. CT scans 6 months after the ESWL treatment demonstrated neither hematoma nor masses in the liver. As a complication of ESWL for urolithiasis a hepatic subcapsular hematoma is very rare. We herein presented the case and discussed the complications of ESWL briefly in the literature.

Female↗
PubMed1998

Comprehensive Sequence Analyses of 5' Flanking Regions of Primate Alu Elements.

Retrotransposons have been generally known to integrate randomly into host genomes. Jurka (Proc. Natl. Acad. Sci. USA 94: 1872-1877, 1977), however, showed consensus sequence patterns at integration sites of certain mammalian retrotransposons, and suggested involvement of sequence specific enzymes that mediate integration. We have conducted comprehensive sequence analyses of 5' flanking regions of primate Alu elements. In contrast to the small but clean data set Jurka (1977) used, (1) larger number of samples were used, (2) wider region of 5' end of Alu elements was analyzed, and (3) comparisons were made among different subfamilies for comprehensive analyses in order to identify characteristic sequence pattern(s) preceding 5' end of Alu elements. The nucleotide occurrences at each position within 500 bases of 5' end of Alus were counted to obtain profiles. Information content at each nucleotide position in the same region was, then, computed. Distinctive difference in the nucleotide composition and information content values that divides the region into two was observed. The region between -20 and 5' end of Alu elements is found to be highly adenine-rich and shows significantly higher information content values compared to the rest of the region, implying the existence of certain characteristic sequence pattern in this region. Also, younger subfamilies of Alu elements show higher information content values than older subfamilies. This implies that certain characteristic sequence pattern already existed in the region between -20 and 5' end of Alu elements at the time of Alu integration, and accumulation of mutation in the course of time resulted in the less distinctive sequence pattern in older sequences. Frequencies of all possible triplets (total of 64) were measured in the same region in order to identify characteristic sequence pattern(s). Observation that frequencies of triplets aaa, taa and tta in the 5' flanking sequences were high is consistent with Jurka (1977). Frequencies of some other triplets such as gaa, caa, aac, ctt, gtt, atg, etc. which do not comprise the primary candidates for the nick site in Jurka (1977) also show significantly high frequencies.

Journal Article↗
PubMed1998

[An experience of video-assisted thoracoscopic surgery for an intrapulmonary needle under CT-guided marking].

A 46-year-old female visited a near hospital, complaining of repeating skin eruption with spontaneous remission. A chest X-ray and CT examinations revealed a needle in the left S6, about 5 mm in length, which was suspected of causing the eruption. She was admitted to our hospital for operation. After CT-guided marking, video-assisted thoracoscopic surgery was performed. Because the needle was too small to be palpable, we decided to respect of it with the lung surrounding the marker and clamped the lung, followed by finding the needle finally. The analysis of the removed needle showed that it contained lead and tin besides iron, nickel and chromium, which are components of stainless steel. Although dermatological examination could not reveal the relation between the needle and the eruption, it has never recurred since the operation. It is thought that CT-guided marking is very useful for resection of an intrapulmonary needle and that a foreign body should be removed for the possibility of being harmful.

Endoscopy↗
PubMed1998

[Epidemiology of acute coronary syndrome].

We reviewed the epidemiology of ischemic heart disease (IHD) focusing on acute myocardial infarction (AMI) in Japan. The age-adjusted mortality from IHD and the age-adjusted incidence of AMI in Japan were nearly the lowest in the world. Vital statistics of Japan showed that the age-adjusted mortality from IHD and AMI had been decreasing since the 1970's until 1993. Rates of new patients of AMI per day have been stable since the early 1980's according to "patient survey". Several population-based studies reported the unchanged age-adjusted incidence of AMI since the late 1950's. In conclusion, the mortality from IHD and the incidence of AMI are very low in Japan, and there is no epidemiological evidence showing an increase in either one.

Acute Disease↗
PubMed1997

Modulation of the arterial baroreceptor reflex by the vasopressin receptor in the area postrema of the hypertensive rats.

The role of arginine8-vasopressin (AVP) in regulation of the baroreceptor reflex in the area postrema was examined in anesthetized hypertensive rats. The sensitivity of the baroreceptor reflex in a one-kidney one clip (1K1C) hypertensive rats was increased in only the initial stage (2 weeks), in association with increase in blood pressure, and then returned to the normal level. This increase in the sensitivity of the baroreceptor reflex in the initial stage was reversed by microinjection of a V1 or V2 antagonist (1 microg) into the area postrema. AVP V2 receptor mRNA was expressed temporarily in the area postrema in this period. These results suggest that vasopressin receptors in the area postrema is important in regulating the sensitivity of the baroreceptor reflex.

Animals↗
PubMed1997

YSK1, a novel mammalian protein kinase structurally related to Ste20 and SPS1, but is not involved in the known MAPK pathways.

To clarify the upstream regulatory mechanism of mitogen-activated protein kinase (MAPK), we performed the reverse transcriptase-based polymerase chain reaction (RT-PCR) with degenerate primers synthesized based on sequences conserved among the kinase domains of yeast MAPK kinase kinases (MAPKKKs), Stell, Bck1, and Byr2. We isolated several mammalian cDNA fragments that encode kinase subdomains sharing significant sequence homology with yeast MAPKKKs. Subsequent screening of a HeLa cell cDNA library using one of these cDNA fragments as a probe resulted in the isolation of a full-length cDNA that encodes a novel protein kinase. The catalytic domain sequence of this gene product is closely related to those of budding yeast Sps1 and Ste20 protein kinases. Thus, we call this protein YSK1 (Yeast Sps1/Ste20-related Kinase 1). The transcript of YSK1 was detected in a wide range of tissues and cells. Immunoprecipitated YSK1 shows protein kinase activity. Although YSK1 is significantly similar in its kinase domain to kinases of the yeast and mammalian MAPK pathways, the overexpression of YSK1 did not lead to the activation of the ERK (extracellular signal-regulated kinase) pathway, JNK (c-Jun NH2-terminal kinase)/SAPK (stress-activated protein kinase) pathway, or p38/Mpk2 pathway. These results suggest that YSK1 may be involved in the regulation of a novel intracellular signaling pathway.

Amino Acid Sequence↗
PubMed1997

Hierarchical Structure of Lattices in Film Formation of Core-Shell Type Polymer Microspheres

By adding polystyrene homopolymer in the solid state, super-lattice structures of poly(4-vinyl pyridine) core-polystyrene shell type polymer microspheres were hierarchically changed from a disordered state to a face-centered cubic via a body-centered cubic. The transition of the lattice structures was investigated from the view point of the excluded volume of the microsphere, which was controlled by a changing of the molecular weights and blend tarios of polystyrene homopolymers.

Journal Article↗
PubMed1997

Epithelial hyperplasia of the larynx a clinical follow-up study.

In this retrospective study, the records of 40 patients with epithelial hyperplasia of the larynx, seen between 1980-1991, were reviewed to determine the incidence of malignant transformation during long term follow-up. The mean follow-up time was 58.6 months. The initial pathological diagnoses were hyperkeratosis in one case, parakeratosis in one, dyskeratosis in 12 and dysplasia in 26. During follow up, nine patients developed carcinoma in situ and/or invasive carcinoma. Of these, two patients had been diagnosed with dyskeratosis without dysplastic cells at the initial biopsy. It is therefore important to follow up patients with epithelial hyperplasia of the larynx even when no dysplastic cells are found at the time of diagnosis.

Adult↗
PubMed1997

Reduction of infarct volume by halothane: effect on cerebral blood flow or perifocal spreading depression-like depolarizations.

Halothane is a strong inhibitor of potassium evoked spreading depression (SD) in cats. In the current study, we investigate halothane effects on induction of perifocal SD-like depolarizations, CBF, and infarct evolution in focal ischemia. Calomel and platinum electrodes measured cortical direct current potential and CBF in ectosylvian, suprasylvian, and marginal gyri. Left middle cerebral artery occlusion (MCAO) induced permanent focal ischemia for 16 hours in artificially ventilated cats (30% oxygen, 70% nitrous oxide) under halothane (0.75%, n = 8) or alpha-chloralose anesthesia (60 mg/kg intravenously, n = 7). Under alpha-chloralose, MCAO induced severe ischemia in ectosylvian and suprasylvian gyri(mean CBF < 10 mL/100 g/min), and direct current potentials turned immediately into terminal depolarization. In marginal gyri, CBF reduction was mild (more than 20 mL/100 g/min), and in six of seven animals, frequent SD-like depolarizations turned into terminal depolarization at a later stage of the experiments. Under halothane, MCAO induced severe ischemia (less than 10 mL/100 g/min) and immediate terminal depolarization only in ectosylvian gyrus. In suprasylvian gyrus, residual CBF remained significantly higher (more than 10 mL/100 g/min) than under alpha-chloralose, whereas in marginal gyri, CBF did not differ between groups. Compared with chloralose, the number of transient depolarizations was significantly reduced in marginal gyrus, and in suprasylvian gyrus transient but significantly longer depolarizations than in marginal gyrus were recorded. Except for one animal, transient depolarizations did not turn into terminal depolarization under halothane, and infarct volume reduction was particularly seen in suprasylvian gyrus. We conclude that halothane, the most commonly used anesthetic in studies of experimental brain ischemia, has protective properties, which may depend on both cerebrovascular and electrophysiologic influences.

Anesthetics, Inhalation↗
PubMed1997

[Retroperitoneal malignant Schwannoma in the pelvis: a case report].

We report a case of malignant Schwannoma in the retroperitoneal space and discuss the clinical features briefly. A 77-year-old male visited our hospital in August, 1994 with the chief complaint of bloody stool. Digital rectal examination disclosed a large, elastic and soft mass in the prostatic region, presented identically by ultrasonography and computed tomography. Histological examination of the mass by transperineal biopsy revealed benign cellular Schwannoma. The patient underwent radical prostatectomy including the tumor because the tumor and the prostate could not be separated. Histological examination of this specimen also revealed benign Schwannoma with normal prostatic tissue. However, 2 months after the operation an abdominal CT scan revealed multiple metastasis in the liver, which was later diagnosed as malignant Schwannoma histologically. He is still alive with hepatic metastasis 15 months postoperatively.

Aged↗
PubMed1996

Antidiuretic action of tachykinin NK-3 receptor in the rat paraventricular nucleus.

Studies were performed on the central antidiuretic actions via the tachykinin NK-3 receptor in the rat hypothalamic paraventricular nucleus (PVN). Microinjections of the selective tachykinin NK-3 receptor agonist senktide (2-200 pmol) into the PVN resulted in prolonged inhibition of urine output in water-loaded rats, its effect being dose-dependent. The antidiuretic action of senktide was blocked by pretreatment with the vasopressin V2 receptor antagonist OPC-31260 (1 mg/kg, i.v.), but not by microinjection of the angiotensin II AT-1 receptor antagonist losartan (1 nmol) into the PVN. NK-3 receptor mRNA was strongly detected in the magnocellular part of the PVN and the supraoptic nucleus (SON) of the hypothalamus as detected by in situ hybridization histochemistry. Moreover, [3H]senktide binding sites were also detected in the PVN and the SON by receptor autoradiography. These findings suggest that NK-3 receptors in the PVN may be involved in water regulation by stimulation of vasopressin secretion from the posterior pituitary gland, and that vasopressin caused water reabsorbtion via the kidney V2 receptor.

Angiotensin Receptor Antagonists↗