Search PubMed⌕ Search

Biomedical subjects

T Doi

Publications and source records attributed to T Doi.

At least 253 records · Page 14Linked to original sources
PubMed1995

Effects of class IA antiarrhythmic drugs on the reentrant circuit in common human atrial flutter.

In 9 patients with the common type of atrial flutter (AF), a zone of slow conduction was observed proximal to the coronary sinus orifice. Class IA antiarrhythmic drugs were administrated intravenously in all 9 patients. AF was converted to sinus rhythm in only 1 patient. In the remaining 8 patients, although IA drugs suppressed conduction velocity, this effect was not preferential with regard to the zone of slow conduction. Conversion of AF to sinus rhythm by rapid pacing was achieved in these 8 patients. At a critical pacing cycle length, AF was interrupted just after conduction block developed in the zone of slow conduction. A progressive decrease in conduction velocity was observed in the zone of slow conduction for several beats just before the onset of conduction block. In conclusion, class IA drugs facilitate the interruption of AF by rapid atrial pacing by inducing conduction block in the zone of slow conduction.

Adult↗
PubMed1995

Direct enantiomeric separation of platelet-activating factor receptor antagonist SM-10661 by ligand-exchange high-performance liquid chromatography with a copper (II) N,S-dioctyl-D-penicillamine complex.

The enantiomeric separation of SM-10661, a platelet activating factor receptor antagonist, was investigated by HPLC using ligand-exchange chiral stationary phases. The stereoisomers of SM-10661 could all be separated by ligand-exchange HPLC with a Cu(II) N,S-dioctyl-D-penicillamine complex (Sumichiral OA-5000). The mechanism for the resolution includes the involvement of hydrophobic interactions between SM-10661 and Cu(II) D-penicillamine.

Cations↗
PubMed1995

Effect of motilin on colonic motor activity in the interdigestive state in conscious dogs.

The aim of the present study was to investigate the effect of motilin at various doses on colonic motility in the interdigestive state. Colonic motility was investigated in five dogs equipped with strain gauge force transducers on the gastric antrum, and on the proximal, middle, and distal colon. Exogenously infused motilin (0.2, 0.5, 1.0 and 2.0 micrograms/kg-hr) dose-dependently increased colonic motility, but the doses of motilin that significantly enhanced colonic motility were 1.0 and 2.0 micrograms/kg-hr in all areas of the colon. Motilin at 0.2 microgram/kg-hr increased the plasma motilin concentration to almost equal to the physiological peak values. The excitatory effect of motilin (2.0 microgram/kg-hr) was abolished by atropine but was not affected by hexamethonium. These results indicate that exogenously infused motilin, which increased plasma motilin concentration to above the physiological peak level, stimulated colonic motility by affecting postsynaptic cholinergic neurons.

Animals↗
PubMed1995

Effect of chronic pancreatic juice diversion on enteroglucagon secretion and intestinal mucosal growth in dogs.

We developed a new canine model of chronic pancreatic juice diversion from duodenum to distal ileum in order to investigate the effect of pancreatic juice on the secretion of enteroglucagon, and the growth of intestinal mucosa. In seven adult mongrel dogs, the minor pancreatic duct was ligated and excised. Then, 3 cm of duodenal segment including the pancreatic duct was transformed into a small pouch which was anastomosed to the distal ileum. Butter ingestion tests were performed before and after surgery to evaluate the effect of surgery on enteroglucagon secretion. In addition, intestinal mucosal thickness was measured, using specimens taken both at the time of surgery and during autopsy at the end of the study. We observed significant hypersecretion of enteroglucagon and mucosal growth throughout the whole small intestine. However, extent or grade of mucosal growth was not related to the mucosal contact of pancreatic juice. These results suggested that chronic pancreatic juice diversion from duodenum to the distal ileum induced mucosal growth of the whole small intestine and hypersecretion of enteroglucagon may play a important role in this growth.

Amylases↗
PubMed1995

Three-dimensional MRI reconstructions of musculoskeletal tumors. A preliminary evaluation of 2 cases.

We have developed a new method for three-dimensional (3D) reconstruction of malignant bone and soft-tissue tumors from MRI. Data from transverse images of T2-weighted images were transferred into a personal computer. The contours of tumors, major vessels, major nerves and bones were outlined, whereupon the 3D data were processed into a 3D display, using a solid model. The determination of tumor volume both before and after preoperative adjuvant therapy was quantified. The 3D images allowed a better understanding of the relationship between the tumor and the major vessels and nerves, thereby aiding in preoperative planning. The images also provided a quantitative, reproducible measurement of the effect of adjuvant therapy.

Adolescent↗
PubMed1995

[Clinical efficacy of the Porges Urospiral, a reversible intraprostatic spiral stent, in patients with benign prostatic hypertrophy].

The Porges Urospiral, a urethral spiral stent made of stainless steel wire, is designed for patients with benign prostatic hypertrophy. To evaluate the safety and efficacy of the stent, a prospective uncontrolled study was performed on 60 patients who complained of urinary retention (48 patients) or severe dysuria (12 patients) due to prostatic hypertrophy. Four patients had neurogenic disorders resulting in bladder dysfunction. The average age of the patients was 77.4 years old, ranging from 61 to 91 years old. In 48 patients, the stent was used instead of transurethral resection of the prostate (TUR-P) because of the patients poor general conditions, while in 12 patients the stent was transiently used until TUR-P. Subjective symptoms, according to an original scoring system, and objective signs, uroflowmetry measurements and residual urine volume, before and 3 months after stent insertion were compared. The stent was indwelt for more than 3 months in 40 of the 57 patients in whom the stent could be inserted. Out of 37 evaluable patients, subjective symptoms improved in all the patients and objective symptoms improved in 26 patients (70.3%). Complications included urinary incontinence, urination pain, urethral pain, gross hematuria or migration of the stent. Although these complications disappeared in a few days after the insertion of the stent in a majority of the patients, the stent was removed in 17 patients due to complications within 3 months after insertion. The overall clinical efficacy of this stent was 56% in 50 evaluable patients who had no neurogenic disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Efficacy of interferon alfa therapy in chronic hepatitis C patients depends primarily on hepatitis C virus RNA level.

To clarify the viral factors that may predict the therapeutic effect of interferon (IFN) in chronic hepatitis C (CHC) patients, we investigated the quantitative serum hepatitis C virus (HCV) RNA level, genotype, and liver biopsy histological features in 60 patients who were treated with 360 x 10(6) U of natural IFN-alpha for 36 to 48 weeks and for more than 12 months after therapy. A branched DNA (bDNA) assay was used to measure HCV RNA levels. All responders, defined as those individuals with normal alanine transaminase (ALT) levels at 48 weeks after therapy, had less than 2 x 10(6) HCV RNA Eq/mL before administration of IFN. Of 39 patients with RNA levels (less than 2 x 10(6) Eq/L) 23 (59.0%) were responders. The genotype was determined for each patient using type-specific polymerase chain reaction (PCR) primers. There was a significant difference in rate of response between subtype 1b and subtypes 2a and 2b (P < .0002); however, all responders had less than 2 x 10(6) Eq/L independent of genotype. In a multivariate analysis, RNA level was the most statistically significant factor affecting response to IFN. Although disease severity, as defined by histological features, was not statistically correlated with nonresponse, patients that responded to IFN tended to have less severe disease.

Adult↗
PubMed1995

Geographic differences in seasonal variation of mean birth weight in Japan.

Seasonal variation of mean birth weight (MBW), mean gestational period (MGP), and MBW at 40 weeks of gestation (MBW40) in the 15 different prefectures of Japan were analyzed using vital statistics from 1974 to 1983. MBW generally shows a bimodal pattern with two peaks in spring and autumn and two troughs in summer and winter. Seasonality exhibits a general geographic trend: The autumn peak loses its height and the spring peak increases its amplitude as one moves from north to south. This trend suggests that environmental factors are associated with the creation of seasonality in MBW. For MGP the pattern is relatively unimodal with a deep trough in winter; however, a late summer small dip is observed in most cases. According to an analysis of coincidence between the two time series (MBW and MGP) and correlation analysis, the seasonal variation in birth weight basically depends on the gestational period. For MBW40, which represents the fetal growth rate, the seasonality shows a pattern similar to that of MBW. A statistically significant coincidence and a correlation are observed between the time series of MBW and MBW40. These results suggest that the two processes of fetal growth (gestational period and fetal growth rate) are associated with the creation of seasonality in MBW.

Birth Weight↗
PubMed1995

[Effect of antiarrhythmic therapy on late potentials].

The purpose of this paper is to review the presently available information on the effect of antiarrhythmic therapy (medical treatment, catheter ablation and surgery) on ventricular late potentials (LP). Therapeutic efficacy of sustained ventricular tachycardia (SVT) is thought to be prevention of it or changing to hemodynamical stable SVT due to prolongation of cycle length of SVT. No significant correlation between LP and inducibility or suppression of SVT was observed. Prolongation of cycle length of SVT is thought to be related to increase of LP. Correlation between LP and efficacy of catheter ablation is thought to be controversial. LP is thought to be diminished after successful antiarrhythmic surgery.

Anti-Arrhythmia Agents↗
PubMed1995

[A case of renal capsular liposarcoma].

A 53-year-old woman was admitted to the Department of Internal Medicine at our hospital with the primary complaint of pyrexia. Abdominal echography and computed tomography (CT) detected a right renal tumor, and the patient was transferred to our department. Angiography revealed a hypovascular tumor. The main nutrient vessels supplying the tumor were the superior and inferior capsular arteries, which arose from the renal artery. A right renal capsular tumor was suspected from these findings, and radical nephrectomy was performed. Histopathological examination revealed a pleomorphic liposarcoma. Therefore, the patient was given 50 Gy of radiation postoperatively. This is the 14th case of a primary liposarcoma of the renal capsule reported in Japan.

Female↗
PubMed1995

[Suppressed increase of C3 receptors on polymorphonuclear leukocytes by stimulation with C5a in diabetes mellitus].

This study was undertaken to clarify the susceptibility to infection of patients with diabetes mellitus. The complement system is activated through the classical and/or the alternative pathways to produce many kinds of anaphylatoxins in the inflammatory process. One of the anaphylatoxins, C5a, possesses both the strong biological activity of a chemotactic factor and the increasing effect of CR1 and CR3 expression on polymorphonuclear leukocytes (PMNs). It is well known that the complement receptors, CR1 and CR3, on PMNs play important roles in the phagocytosis. We studied the changes of the expression of these receptors on PMNs in non-insulin dependent diabetes mellitus after the stimulation with recombinant human C5a. PMNs from 11 patients with non-insulin dependent diabetes mellitus and 11 normal controls were tested. There was no significant difference of CR1 and CR3 expression on PMNs after the addition of 10 ng/ml C5a between patients with diabetes mellitus and normal controls. However, by the stimulation with 50 ng/ml C5a, the increase of the CR3 expression on PMNs of patients with diabetes mellitus was significantly smaller than normal controls (p < 0.02). The increase of the expression of CR1 on PMNs was not significantly different the two groups. It is suggested that the small increase of the CR3 expression on PMNs by the stimulation with C5a is one of the factors of the susceptibility to infection in patients with diabetes mellitus.

Adult↗
PubMed1995

Malignant transformation of leukoplakia three times in period of 11-years--case report.

Leukoplakia is a commonly occurring precancerous lesion. The following case report describes a patient who had multiple leukoplakia in this mouth. He had three sites of leukoplakia, the left hard palate, the gum of the right maxilla and the gum of the left mandible, all of which underwent malignant transformation during the period of 11-years after diagnosis.

Adult↗
PubMed1994

The histidine interruption of an alpha-helical coiled coil allosterically mediates a pH-dependent ligand dissociation from macrophage scavenger receptors.

Macrophage scavenger receptors uptake modified low density lipoproteins (LDLs) through receptor-mediated endocytosis. In the alpha-helical coiled coil domain, 2 histidines (His168 and His260) disrupt leucine or isoleucine heptad repeats. Substitution of His168 or/and His260 to leucine had no effect on AcLDL binding activities. However, the His260-replaced receptors had their ligand degradation activities diminished. Cell surface ligand release experiments under acidic pH clarified that His260 mutants lost their ligand dissociation activities at 37 degrees C. Furthermore, immunoelectron microscopic experiments using anti-scavenger receptor antibody showed that the His260 replaced receptors were not able to release gold-labeled AcLDL in endosomes. Here we propose an allosterical ligand dissociation mechanism by His260 in macrophage scavenger receptors.

Allosteric Regulation↗
PubMed1994

Hypothalamic neuronal histamine regulates feeding circadian rhythm in rats.

To clarify involvement of hypothalamic neuronal histamine in feeding circadian rhythm, we analyzed rat behavioral patterns using chemical probes which affect endogenous histaminergic activity. Sustained infusion of alpha-fluoromethylhistidine (FMH), a specific suicide inhibitor of a histamine-synthesizing enzyme, into the rat third cerebral ventricle disrupted light-dark cycles of feeding, drinking, and ambulatory behavior. Food and water intake and ambulatory activity during the 12-h light period increased, and those during the 12-h dark period decreased after the infusion. The ratio of the light period to the 24-h total period (L/T ratio) increased in all behavioral parameters. Assessed by 3-h cumulative analysis, amplitudes of circadian rhythmicity decreased in all behavioral parameters, whereas only the acrophase of ambulatory activity shifted forward after FMH infusion. Chlorpheniramine, an H1-antagonist, selectively increased food intake during the light and decreased it during the dark period. Consequently, the antagonist increased the L/T ratio in food intake, but did not affect the ratio in water intake or ambulatory activity. Famotidine, an H2-antagonist, did not affect the ratio in any parameter. Thioperamide, an antagonist of auto-inhibitory effects on histamine synthesis and release at presynaptic H3-receptor sites, decreased food intake during the dark, but did not affect the L/T ratio in any parameter. These findings indicate that neuronal histamine may regulate feeding circadian rhythm through the hypothalamic histamine H1-receptor in rats.

Animals↗
PubMed1994

[Main household occupation and mean birth weight in Japan 1984].

By using the 1984 vital statistics released on magnet tapes by the Japanese government, we observed in the present study how the mean birth weight (MBW) varies from one group of mothers who fall under the same category of "main household job" to another. In so doing, we compared the MBWs among different job categories in terms of mother's age, baby's sex, and parity. The obtained results are summarized as follows: 1) The MBW of primiparae and male babies was found to be significantly different among the job categories in the age range of 20-39. In the group of multiparae and male babies, however, all the age ranges older that twenty showed significant differences in the MBW among the job categories. In the group of female babies, the significant difference was found in the age range of 20-39 and all the ranges older than twenty for primiparae and multiparae, respectively. 2) The above results were considered to be caused mainly by the low MBW in the category of "other" for primiparae, and by the high MBW in "part-time farming" and the low MBW in "other" for multiparae.

Adolescent↗
PubMed1994

Nuclear magnetic resonance study of the interaction of T4 endonuclease V with DNA.

T4 endonuclease V catalyzes the DNA strand cleavage in the vicinity of a thymine dimer. In order to obtain insight into the specific recognition mechanism of this enzyme with a thymine photodimer within DNA, the conformations of five different DNA duplexes, [sequence: see text] with which the enzyme can interact, were studied by 1H NMR. DNA I, DNA IV, and DNA V do not contain the TT sequence or a thymine dimer and hence, are expected to bind the enzyme only in a nonspecific manner. DNA II includes a single TT sequence which does not form a thymine dimer. Only DNA III is expected to bind specifically to the enzyme through a thymine photodimer. The NMR spectra of these five DNA duplexes in the absence of the enzyme clearly show that the formation of a thymine dimer within the DNA induces only a minor distortion in the structure and that the overall structure of B-type DNA is retained. The photodimer formation is found to cause a large change in chemical shifts at the GC7 base pair, which is located at the 3'-side of the thymine dimer, accompanied by the major conformational change at the thymine dimer site. The effects of T4 endonuclease V binding on these DNA duplexes were also investigated by 1H NMR. The binding of this enzyme to DNA I, DNA IV, and DNA V causes no alteration in chemical shift values of the imino proton resonances, but the binding to DNA II induces a small downfield shift in the imino proton resonance of GC7.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Composition↗