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Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 1,027 records · Page 57Linked to original sources
PubMed1986

Characteristic distribution density of organelles in the cytoplasm of respective kinds of cell lineages of ascidian embryos.

In the early embryos of the ascidian (Halocynthia roretzi), regional cytoplasmic differences arise just after fertilization. We successively studied the characteristic features of the cytoplasm of those regions in the embryonic cells during the entire ontogenic process from the unfertilized egg to the tadpole larva. The embryos and larvae were fixed in a mixture of osmium and glutaraldehyde, and the distribution of the organelles in the entire cytoplasm was observed with light and electron microscopy. According to the analysis of the distribution density of the organelles which occupied a given area of the cytoplasm on the section, we introduced the "organelle region" in the cytoplasm and further calculated the approximate area ratios of the "organelle regions" in the cytoplasm of each cell lineage. As a result, it was demonstrated that the characteristic distribution mode was already present in the cytoplasm of the cell lineages of the 8-cell-stage embryos. The features of the cytoplasm in each embryonic cell lineage, moreover, reflected those of the corresponding larval tissue. Our results not only demonstrate that the structural tissue specificity is expressed at an extremely early stage during the ascidian embryogenesis but also suggest that the corresponding functional differentiation among the cell lineages occurs early.

Animals↗
PubMed1986

Ultrastructural features of the cytoplasm of respective kinds of cell lineages of cleavage-arrested ascidian embryo.

We observed the ultrastructural features of the cytoplasm in the cell lineages of the cleavage-arrested embryos of the ascidian, Halocynthia roretzi, and compared them with those of the cytoplasm in the corresponding cell lineages of the normal embryos or in the corresponding tissues of the normal larva, in order to examine the presence or the degree of the cellular differentiation without the cleavage. The cleavage of the embryos was arrested by the cytochalasin B at the 16-cell and the embryos were cultured in sea water containing cytochalasin B until the developmental time equivalent to the hatching of the control larva. As a result, the cytoplasmic components in the cleavage-arrested 16-cell embryos resembled those observed in the corresponding tissues of the normal larvae, especially in the b5.3 and b5.4 blastomers (epidermal lineage cells) and in the B5.1 blastomeres (which give rise to the endodermal, mesenchymal and muscle cells) but they were less uniformly organized and their polarity or orientation was very random and irregular, compared with those in the normal larvae. These results demonstrated that the morphological differentiation similar to the larval tissue differentiation could proceed even in the cleavage-arrested embryos to a certain extent.

Acetylcholinesterase↗
PubMed1986

[In vitro susceptibilities of BRL 25000 (clavulanic acid-amoxicillin) against causative organisms in the field of obstetrics and gynecology].

The in vitro susceptibilities of various causative organisms recently isolated from patients with genital infections to BRL 25000 (a formulation with 2 parts of amoxicillin and 1 part of potassium clavulanate), amoxicillin (AMPC), cefaclor (CCL), cephalexin (CEX), cefadroxil (CDX) and cefroxadine (CXD) were determined. beta-Lactamase-producing strains were detected by the nitrocefin disc method. Frequencies of isolation of beta-lactamase producing strains of E. coli, K. pneumoniae and B. fragilis were 36%, 96% and 100%, respectively. The activity of BRL 25000 against S. agalactiae and anaerobic GPC (anaerobic Streptococci, Peptostreptococcus spp.) was slightly less than that of AMPC but was 2- to 4-fold higher than CCL and 8- to 16-fold higher than CEX, CDX and CXD. Against E. coli and K. pneumoniae, the activity of BRL 25000 was superior to that of AMPC and approximately equal to CEX, CDX and CXD but 2-fold less than CCL. Against the B. fragilis group, BRL 25000 was much more active than AMPC or any of the cephalosporins tested, clearly demonstrating the beta-lactamase inhibitory properties of the clavulanic acid in BRL 25000. At inocula of 10(6) CFU/ml, MIC values of BRL 25000 were 12.5-50 micrograms/ml against some strains of E. coli, K. pneumoniae and B. fragilis. A mechanism of resistance other than beta-lactamase production is obviously prevalent in these strains. It is speculated that the resistance may be due to a low affinity of the drug to target proteins. Mixed infections of B. fragilis and E. coli or K. pneumoniae are commonly found in the obstetric and gynecological patients. BRL 25000 shows activity against these strains and also against both aerobic and anaerobic GPC. Therefore, BRL 25000 is considered useful for the treatment of genital infections.

Amoxicillin↗
PubMed1986

A Raman spectroscopic study on the sequence dependent conformations of DNA oligomers.

Eighteen kinds of oligodeoxyribonucleic acids have been examined to reveal their structures in aqueous solutions at different ionic strengths by Raman spectroscopy. The structures in solutions were found to be very polymorphic depending on their sequences as well as on the salt concentrations. At a low salt condition a DNA oligomer assumes a unique B form within a B family, for examples Ba, Bh, B', or Bn form. Amongst these DNA oligomers, d(CGCG)2 showed a salt induced Ba-Z transition, while d(GGGGCCCC)2 showed a salt induced Bh-A transition. DNA oligomers with AA/TT sequences were found to prefer B' form even at high salt condition. From comparing the structures of DNA oligomers in solutions with their crystal structures, it is safe to say that the crystal structure of a DNA oligomer is very similar to the structure in the high salt solution.

Base Sequence↗
PubMed1986

[Midecamycin acetate-susceptibility of clinical isolates from dental and oral surgical infections].

To investigate the clinical and bacteriological usefulness of orally administered midecamycin acetate (MOM), the susceptibility of clinical isolates to MOM, Mb-12 (the main metabolite of MOM), josamycin (JM), ampicillin (ABPC) and cephalexin (CEX) was determined. The results are summarized as follows. Antibacterial activities of MOM against aerobic Gram-positive cocci, B. catarrhalis, and anaerobic bacteria were inferior to those of JM by 2-fold, but superior to those of CEX. Activities of MOM against S. aureus, Bacteroides spp., Fusobacterium spp., Veillonella spp. were superior to those of ABPC and CEX. Since serum and tissue concentrations of Mb-12 after 200 mg administration in humans have been reported to be 1-2 micrograms/ml, it can be presumed that the causative bacteria would be eradicated by a usual dosage of MOM used in the present study. From these considerations, it is speculated that MOM may be successfully used in the treatment of dental and oral surgical infections.

Ampicillin↗
PubMed1986

[Study of concentrations of clindamycin phosphate in bone marrow blood and tissue].

Clindamycin phosphate (CLDM) was administered to 33 surgical cases in orthopedics to treat or prevent infection (600 mg in 15 cases and 1,200 mg in 18 cases by intravenous drip infusion over 60 minutes) and the concentrations of CLDM in the bone marrow blood and tissue of the operative field as well as in venous blood were determined with the cup plate method of bioassay by collecting specimens immediately after completion of infusion or 30 or 60 minutes later. The concentration of CLDM in bone marrow blood averaged 104.3 approximately 105.5% of the corresponding concentration in venous blood in the cases receiving 600 mg and 101.3% in those receiving 1,200 mg. The concentration of CLDM in bone marrow tissue averaged 154.0 approximately 163.7% of the corresponding concentration in venous blood in the group receiving 600 mg but 78.8 approximately 86.2% in the group receiving 1,200 mg. This difference between the 2 groups was considered to reflect largely the difference in specimens collected. Thus, the concentration of CLDM in bone marrow tissue was interpreted as the amount of drug penetrating and remaining in bone marrow tissue and its adjacent area. The MIC75 of CLDM for clinical isolates were 0.20 micrograms/ml for S. aureus, 0.78 micrograms/ml for B. fragilis and 0.20 micrograms/ml for Peptostreptococcus spp. The concentrations of CLDM attained in bone marrow blood and tissue and its adjacent area after administration of 600 mg or 1,200 mg were thus sufficient to eliminate these organisms. The above results indicate that CLDM is a useful antibiotic for treatment and prevention of infection in orthopedics.

Adolescent↗
PubMed1986

[Studies on antimicrobial concentration of clindamycin phosphate in serum, pelvic dead space exudate, and pelvic organs/tissues].

In women undergoing radical and total abdominal hysterectomy, clindamycin phosphate (CLDM-P) in a dose of 1,200 mg was administered by intravenous drip infusion over 1 hour and the drug concentrations in serum and pelvic dead space exudate, as well as pelvic organs/tissues, were determined over time. The following results were obtained: The serum concentration of clindamycin (CLDM) after intravenous infusion showed the peak value of 24.54 +/- 7.02 micrograms/ml at the end of infusion and then gradually decreased to 3.87 +/- 0.70 micrograms/ml in 6 hours. Concentration in pelvic dead space exudate, which was 2.82 +/- 3.90 micrograms/ml at the end of intravenous infusion, gradually increased to the peak value of 13.49 +/- 6.62 micrograms/ml in 1 hour. Two hours after infusion, the level of 12.43 +/- 5.56 micrograms/ml outstripped serum concentration. Continuously in excess of serum concentration, the exudate concentration gradually decreased to 6.65 +/- 2.27 micrograms/ml at 6 hours after infusion. Cubital venous serum concentration (16.36 +/- 3.68 micrograms/ml) was almost equal to uterine arterial serum concentration (16.36 +/- 4.05 micrograms/ml) of CLDM at uterine removal. In the pelvic organ/tissue concentrations, 15.71 +/- 3.86 micrograms/g in endometrium was highest, followed by 15.19 +/- 3.80 micrograms/g in oviduct, 14.80 +/- 3.52 micrograms/g in myometrium, 14.74 +/- 4.02 micrograms/g in ovary, 14.09 +/- 2.90 micrograms/g in portio vaginalis. The concentration was lowest (11.49 +/- 1.44 micrograms/g) in cervix uteri. Clinically, combined treatment with CLDM-P and ceftizoxime was excellently effective for endometritis induced by P. asaccharolyticus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Clinical evaluation of thermoradiotherapy for deep-seated tumors].

Between October 1981 and February 1985, RF capacitive heating with frequencies of 8 and 13.56 MHz was combined with radiotherapy in the treatment of 28 deep-seated tumors that were previously considered incurable by conventional radiotherapy alone. Intra-tumor temperatures of higher than 42 degrees C were achieved in 69% of overall heat sessions. Clinical evaluation was made by calculating the percentage of tumor regression from pre- and post-treatment CT films. As for the criteria of clinical evaluation, complete regression (CR) was defined as clinical disappearance of any measurable tumor, partial regression a and b (PRa and PRb) as regressions of 80% or more and 50 to less than 80%, respectively, and no response (NR) as less than 50% regression. Of 28 deep-seated tumors, 4 (14%) achieved CR, 5 (18%) PRa, 11 (39%) PRb and 8 (29%) NR. In some NR and PRb tumors, however, CT scan revealed remarkable increases in low density areas that suggested necrosis of tumor tissues. This was proved by subsequent histological examination. Clinical tumor response appeared to decrease as the initial size of the tumor increased and to be independent of any TDF factor for radiotherapy and the number of heat sessions.

Combined Modality Therapy↗
PubMed1986

[Radiation-induced cancers following radiotherapy of benign diseases: the second mail survey in Japan].

On a second mail survey (in 1984) concerning radiation-induced cancer following radiotherapy for benign diseases, 86 cases were collected from 95 hospitals in Japan. Adding these to 150 cases collected in the previous survey in 1979, 236 cases were accumulated. This is a report on the analysis of the 236 cases from a clinicopathological viewpoint. Underlying diseases consisted of cervical tuberculous lymphadenitis (125 cases), skin diseases (41 cases), benign thyroid diseases (19 cases), hemangioma (18 cases) and others (33 cases). Radiation-induced cancers, which were defined as cancers originating in the radiation field, including leukemia, consisted of hypopharyngeal cancer (68 cases), skin cancer (61 cases), laryngeal cancer (26 cases), esophageal cancer (23 cases), thyroid cancer (23 cases), salivary gland tumor (8 cases) and others (27 cases). Multiple primary cancers in the radiation field were observed in 7 cases. Average latent period was 28.9 years. It was demonstrated that the older the age at irradiation the shorter the latent period. Based on the population irradiated for benign diseases before 1977, which was collected in the first mail survey, incidence of radiation-induced cancers was estimated to be about 0.9%. The incidence varied with the period of radiotherapy; 1.9% for the period of radiotherapy before 1955, 0.4% for 1956-1965, 0.1% for 1966-1977. Although radiotherapy is now rarely indicated for benign diseases, it was shown in the first mail survey that more than 15,000 cases of benign diseases had been irradiated after 1956. It seems to be reasonable to consider that radiation-induced cancers after radiotherapy for benign diseases may continue to be discovered for several years in the future.

Adolescent↗
PubMed1986

[Effects of pentobarbital on brain lipid metabolism during global ischemia].

It is known that pentobarbital, which has been used for severe brain infarct or head injury as a brain protective drug, inhibits the increase of free fatty acids (FFAs) liberated from membrane phospholipids during ischemia. However, the mechanisms of FFA liberation from phospholipids and the mode of action of pentobarbital are still unclear. Therefore we have investigated the effects of induction of global ischemia and pentobarbital pretreatment upon lipid metabolism in rat brain. Brain ischemia was evoked by rat decapitation and pentobarbital (60 mg/kg) was administered i.p. for 15 min prior to decapitation. Removed brains were incubated for 1, 5, 15 or 30 min at 37 degrees C and then quickly frozen in liquid nitrogen. After extraction of lipids from the brains, neutral lipid and phospholipid compositions were analyzed by thin-layer and gas-liquid chromatography. The results demonstrated that FFAs, either unsaturated or saturated, were rapidly accumulated in the brain during early period of ischemia, but attenuated significantly by pentobarbital pretreatment. Pentobarbital attenuated the accumulations of stearic and arachidonic acids, with little effect on palmitic and oleic acids. Diacylglycerol (DG), which is considered to be as a plausible candidate for the source of FFA, was also produced in the ischemic brain, and its acyl chain composition was similar to that of liberated FFAs. Furthermore, the increase of DG was inhibited significantly by pentobarbital anesthesia. In particular, pentobarbital attenuated the accumulation of DG enriched in arachidonic and stearic acids. This fatty acyl composition resembled the principal composition of phosphatidylinositol (PI) in rat brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[A family of hereditary communicating hydrocephalus with trigonocephaly].

We studied a family of hereditary hydrocephalus with trigonocephaly, affecting eight members (four males and four females) across two generations. A proband in this family was 51 year old man, who complained of nonprogressive gait disturbance after the age of 20 years. He was admitted to our hospital because of non-neurological disease. Accidentally urinary incontinence appeared and then CT scan was performed, which revealed marked dilatation of the lateral ventricles. He was short stature and showed trigonocephalic forehead, but his head circumference was 56 cm. Mild dementia, spastic gait and hyperreflexia were observed on neurological examinations. A lumbar puncture disclosed that cerebrospinal fluid pressure was 115 mm H2O and sugar, protein and cells were normal. His skull X-ray film demonstrated temporal buldging of the calvarium, but its breadth length and height were within normal limits. Sagittal, coronal and lomboid sutures were not fused. However, skull bones were thinned and the top of dorsum sellae was erosive. A marked symmetrical dilatation of lateral, third and fourth ventricles were found in CT scan, to the contrary, bilateral Sylvian fissures and cortical sulci were slightly widened. On R.I. cisternography, ventricular reflux was noted during 3 to 72 hours after the injection. No accumulation of R. I. was observed in the parasagital region. In the arterial phase of the right carotid angiography, slight displacement was noted in Sylvian branches of bilateral middle cerebral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[A study of concentration of ampicillin into middle ear effusion after administration of bacampicillin].

We studied the concentration of ampicillin (ABPC) into middle ear effusions after administration of bacampicillin (BAPC). Nine patients with acute purulent otitis media were given orally single doses of the drug at a level of 10 mg/kg, and concentrations of ABPC which is the active antibiotic metabolite of BAPC were determined in middle ear effusions periodically after the administration. Bacteria present in effusions were identified, and their ability to produce beta-lactamase was also determined. ABPC concentrations in middle ear effusions were inversely related to the ability of bacteria detected from the intratympanic cavity to produce beta-lactamase. ABPC concentrations in middle ear effusions from which only beta-lactamase negative organisms were detected were higher by 5.2- and 2.3- fold at 60 and 120 minutes after the administration of BAPC, respectively, than those in effusions from which beta-lactamase positive organisms were detected. ABPC concentrations achieved in middle ear effusions in cases where only beta-lactamase negative organisms were detected exceeded MIC80's of the drug against main causative bacteria of acute purulent otitis media such as Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae. Because only 10% or less of these species produces beta-lactamase, BAPC appears to be one of the highly effective drugs in the treatment of this disease.

Acute Disease↗