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Biomedical subjects

Y Miwa

Publications and source records attributed to Y Miwa.

At least 145 records · Page 8Linked to original sources

Primitive erythropoiesis of mouse teratocarcinoma stem cells PCC3/A/1 in serum-free medium.

Mouse teratocarcinoma stem cells PCC3/A/1 differentiated into various types of cells, such as red cells, when they were grown in serum-free medium containing transferrin and bovine serum albumin on a KCF cell feeder layer. These red cells were stained well with 2,7-diaminofluorene (DAF), and therefore were erythroid cells. They were nucleated and contained embryonic globin chains, immunologically identified with antiembryonic hemoglobin antisera after acid urea Triton X-100 polyacrylamide gel electrophoresis (UT-PAGE). The addition of erythropoietin to the culture medium enhanced the production of both embryonic and adult globin chains. The addition of interleukin-3 also enhanced the production of embryonic globin chains, but not the production of adult globin chains. These results indicated that primitive erythropoiesis of PCC3/A/1 teratocarcinoma cells did not require exogenous addition of any hematopoietic factor such as erythropoietin or interleukin-3. This culture system will be a new model system for investigating the factors regulating the primitive erythropoiesis in yolk sac blood islands.

Animals↗

Intraoperative radiation therapy for malignant glioma.

Intraoperative radiation therapy (IORT) was used as part of the initial therapy for malignant glioma in 32 of 73 patients with histologically verified anaplastic astrocytoma (grade III astrocytoma) and glioblastoma multiforme. The initial treatment for all cases was subtotal or total tumor resection combined with external irradiation and chemotherapy. IORT was performed 1 week after tumor resection, with doses of 10-50 Gy (mean 26.7 Gy) in one session. Fourteen of 32 cases had IORT two times because of tumor recurrence. The IORT patients had survival rates at 24 and 36 months after initial treatment of 57.1 and 33.5% (median survival 26.2 months). The other 41 patients had 23.6 and 13.1% survivals (median survival 20.7 months), which were significantly lower (p less than 0.01). Tumor recurrence within the original lesion site was suspected because of clinical condition, computed tomography, and magnetic resonance imaging studies in 65.6% of the IORT group (21 cases) 12 months after initial treatment. Twenty cases of death in the IORT group, including five autopsy cases, demonstrated regional tumor recurrence with a high incidence of intraventricular tumor invasion. The authors consider IORT is beneficial for selected malignant glioma patients, including tumor recurrence, because of prolonged survival.

Adolescent↗

[Thymidylate synthase inhibition and concentration of 5-fluorouracil after administration of UFT in human uroepithelial carcinomas].

Inhibition of thymidylate synthase (TS) and the concentration of tegafur, 5-FU and uracil in the tumor and the non-tumor tissues were compared in 18 uroepithelial cancer patients who had been administered UFT (600 mg/day) for seven days before operation. 5-FU and uracil levels in the tumor tissue were increased to 5.1 and 3.6 fold, respectively, compared those in the normal tissue, although there was no difference in tegafur levels between normal and tumor tissue. The mean inhibition rate of TS activity in the tumor tissue was significantly higher (36%) than that in the normal tissue (21%). However, no correlation between 5-FU level and inhibition rate of TS activity was found in either tissue. Not only the higher tumor concentration of 5-FU but also the higher inhibition of TS activity in the tumor tissue suggests that UFT is likely a useful drug for the treatment of uroepithelial carcinomas.

Adenocarcinoma, Mucinous↗

Determination of the cis sequence involved in catabolite repression of the Bacillus subtilis gnt operon; implication of a consensus sequence in catabolite repression in the genus Bacillus.

The mechanism underlying catabolite repression in Bacillus species remains unsolved. The gluconate (gnt) operon of Bacillus subtilis is one of the catabolic operons which is under catabolite repression. To identify the cis sequence involved in catabolite repression of the gnt operon, we performed deletion analysis of a DNA fragment carrying the gnt promoter and the gntR gene, which had been cloned into the promoter probe vector, pWP19. Deletion of the region upstream of the gnt promoter did not affect catabolite repression. Further deletion analysis of the gnt promoter and gntR coding region was carried out after restoration of promoter activity through the insertion of internal constitutive promoters of the gnt operon before the gntR gene (P2 and P3). These deletions revealed that the cis sequence involved in catabolite repression of the gnt operon is located between nucleotide positions +137 and +148. This DNA segment contains a sequence, ATTGAAAG, which may be implicated as a consensus sequence involved in catabolite repression in the genus Bacillus.

Bacillus subtilis↗

Evidence for posttranscriptional regulation of synthesis of the Bacillus subtilis Gnt repressor.

Transcription of the Bacillus subtilis gnt operon results in a polycistronic mRNA that encodes from the 5' end the Gnt repressor, gluconate kinase and permease. The RNA is drastically induced through inactivation of the Gnt repressor by gluconate. The results of deletion analysis of the gnt promoter region upstream of the repressor gene indicated that no other promoter except the gnt promoter was present for expression of the gluconate kinase gene. In contrast to the synthesis of gluconate kinase and permease, which was markedly induced by gluconate, the results of a radioimmunoassay for the Gnt repressor indicated that synthesis of the Gnt repressor from the induced mRNA was posttranscriptionally repressed.

Amino Acid Sequence↗

Structure and hypotensive activity relationships of tetrandrine derivatives in stroke-prone spontaneously hypertensive rats.

1. Structure and hypotensive activity relationships of tetrandrine (TD), an alkaloid isolated from the Chinese herb Radix stephaniae tetrandrae and its derivatives were investigated in conscious stroke-prone spontaneously hypertensive rats (SHRSP). 2. Derivatives substituted at the 7-O position with various types of alkyl group produced varying degrees of hypotensive effect. 3. While the demethylated derivative, fangchinoline (FC), and its acetylated compound had no effect on blood pressure, 7-O-methyl FC (TD), and 7-O-ethyl and 7-O-isopropyl FC at oral doses of 25 and 50 mg/kg produced a gradual and sustained hypotensive effect without any significant effects on heart rate and plasma renin concentration. 4. Substitution at the 7-O position with longer side chains such as n-propyl, n-butyl and n-pentyl groups reduced both the degree and duration of hypotensive activity. 5. Substitution of N-methyl groups at the 2 and 2' positions with quaternary ammonium or N-oxide attenuated the hypotensive activity. 6. The results of this study suggest a possibility that 7-O-ethyl and 7-O-isopropyl derivatives as well as TD can be considered as potential antihypertensive drugs because of the gradual onset and long duration of their hypotensive action in SHRSP.

Alkaloids↗

A chondrogenic cell line derived from a differentiating culture of AT805 teratocarcinoma cells.

A cell line, ATDC5, isolated from a differentiating culture of AT805 teratocarcinoma expressed a fibroblastic cell phenotype in a growing phase. With the addition of 10 micrograms/ml insulin to the medium, cells continued to grow even in a postconfluent phase, formed cartilage nodule-like cell aggregates, were stained with Alcian blue and produced cartilage-specific proteoglycan and type II collagen, typical marker molecules for chondrogenesis. Since ATDC5 cells also differentiated into unidentifiable pigmented cells, they are apparently composed of undetermined cells. ATDC5, therefore, provides a good model system with which to understand chondrogenic differentiation.

Animals↗

Tumors at the trigone of the lateral ventricle--clinical analysis of eight cases.

Tumors at the trigone of the lateral ventricles are relatively rare. The authors have operated on eight cases with trigonal tumors during a 10-year period. Four cases were true intraventricular tumors arising from the ventricular walls, consisting of two meningiomas, one cavernous angioma, and one choroid plexus papilloma. On the other hand, the remaining four cases were paraventricular tumors originating in the adjacent brain and consisted of three astrocytomas and one glioblastoma multiforme. Although these trigonal tumors were readily detected with computed tomographic (CT) scanning, differential diagnosis was difficult because of their similar appearances on CT scans. The initial symptoms were headache in seven, and the neurological examination revealed personality changes, choked disc, visual field defects, hemiparesis, etc., in four, and no deficits in the remaining four cases. All cases were operated on via superior or middle temporal gyrus incision, and the surgical results were good except for one case who died of postoperative brain edema. In the four cases with tumors located in the dominant hemisphere, two were left with sensory aphasia, dyslexia, dyscalculia, and hemianopsia which improved within 6 months. In these two cases, postoperative CT scans revealed cerebrospinal fluid retention with severe edema along the surgical route which disappeared spontaneously within 3 months. We consider that the temporal gyrus incision was the safest approach, even though the tumor was located in the dominant side.

Adolescent↗

[Treatment of nausea and vomiting induced by a 24-hour i.v. infusion of cisplatin].

Nine advanced gastric cancer patients were given 17 courses of cisplatin administrations by means of a 24-hour intravenous infusion at a dose of 100 mg/m2. For an anti-emetic, 40 mg of metoclopramide was administered 5 times at 6-hour intervals, along with a 500 mg hydrocortisone administration at the start of the cisplatin infusion. Despite this preventative treatment, nausea and/or vomiting occurred in over one-third of all the courses. Thus, to combat this nausea and/or vomiting, a combination of lorazepam (1.5 mg/day, divided into 3 p.o.), dexamethasone (20, 10 and 10 mg by i.v. at 3, 8, and 24 hours, respectively, after start of the cisplatin infusion), and a 60 mg intravenous administration of metoclopramide (5 times at 6-hour intervals) was given, and it was found that this new method (Method IV) prevented both nausea and vomiting.

Antineoplastic Combined Chemotherapy Protocols↗

[Effect of endothelin on gastric mucosal lesion in rats].

Gastric mucosal blood flow and gastric mucosal prostaglandin E2 (PGE2) and prostacyclin (PGI2) were investigated in male Wistar rats intraarterially injected with endothelin (ET), an endothelium-derived vasoconstrictor peptide. Immediately following ET (4 nmol/kg) administration, gastric mucosal blood flow decreased. Then 30 min later, the blood flow reached the minimum, but PGE2 and PGI2 showed the highest value. PGE2 showed a tendency to decrease 90 min later, while PGI2 continued to show high value. There were redness and hemorrhagic damage in the gastric mucosa. Endogenous PGs were presumed to be relate to the regulation of the development of the mucosal damage owing to decrease in the blood flow after ET administration.

Animals↗

[Cerebellar infarction: analysis of 33 cases].

During the past 9 years and 2 months we have encountered 33 cases with cerebellar infarction. These patients were classified into 3 types according to their clinical course. Type 1 (18 cases); The course was benign, and symptoms and signs improved without surgical treatment. Type 2 (11 cases); The course was progressive with deterioration of consciousness between 24-72 hours after the onset. Type 3 (4 cases); The course was rapid resulting in lapse into coma within a few hours. Also, its prognosis was fatal due to coexisting brain-stem infarction regardless of any treatment. Surgical intervention was required for Type 2 in which the lesion included the region of the vermis or occupied more than one-third of the cerebellar hemisphere, and had subsequently compressed the brain-stem and caused obstructive hydrocephalus. In 9 cases out of Type 2, ventricular drainage alone was performed and prompt improvement of consciousness level was detected except in one case. We consider that ventricular drainage is not so invasive a method, and it is beneficial. However, in 2 cases of Type 1 and 4 cases of Type 2, hemorrhagic infarction occurred. Thus, one should be aware of the possibility of hemorrhagic infarction, even though it may be asymptomatic infarction. If prompt improvement of consciousness is not detected after ventricular drainage, suboccipital craniectomy should be recommended.

Adult↗

[Ultrasonographic assessment of intravesical urine volume].

The assessment of intravesical urine volume is very important in the management of the patients with lower urinary tract obstruction or incontinence. As the non-invasive method for measuring residual urine volume, accuracy and usefulness of ultrasonographic measurement was evaluated in a total of 116 occasions in comparison with the conventional catheter technique. The values of the maximum transverse (W), cranio-caudal (H) and antero-posterior distance (D) of the inflated bladder were obtained by trans-abdominal scanning. These parameters were used for the ellipsoid formula (pi/6 x W x H x D). The ultrasonographic measurement of urine volume showed a high coefficiency against the conventional catheterized volume (r = 0.9543). Although a mean standard error was 56.3% of the actual volume, the amount of residual urine at the target of 50 ml and 100 ml could be accurately assessed by ultrasound with an accuracy of 90.5%. The method was also valid in follow-up study to monitor the changes of residual urine volume. The ultrasonographic assessment of intravesical urine volume is, thus, a non-invasive, useful tool in the management of the patients with voiding disturbance.

Evaluation Studies as Topic↗

Treatment of chronic granulocytic leukemia in the accelerated phase by transfusion of autologous buffy-coat cells--a case report.

We treated a patient with chronic granulocytic leukemia (CGL), in the accelerated phase by intensive chemotherapy followed by the infusion of cryopreserved peripheral blood buffy-coat cells. The cells had been stored for 32 months. The chemotherapy consisted of daunorubicin 40 mg X 2 days, vincristine 2 mg X 1 day, cytosine arabinoside (Ara-C) 200 mg X 6 days and prednisolone 30 mg X 7 days in the first week, then Ara-C 3 g/m2 X 3 days and cyclophosphamide 60 mg/kg X 2 days in the second week, but reversion to the chronic phase was not achieved. Therefore, total body irradiation (TBI) was added to repeated intensive chemotherapy followed by infusion of the remaining cells. Marrow recovery was good. The patient is currently alive and has been in the chronic phase for 22 months. This preliminary result indicates that this therapy may be tried soon after transformation in CGL and that TBI is an important part of therapy in BMT in the accelerated or blastic phase of CGL.

Adult↗

Identification of an operator sequence for the Bacillus subtilis gnt operon.

Expression of the Bacillus subtilis gluconate (gnt) operon is negatively regulated by the gnt repressor which is antagonized by D-gluconate or D-glucono-delta-lactone. The repressor specifically binds to a gnt operator near the gnt promoter. From the results of gel retardation assaying of the gnt repressor and various restriction enzyme digests of a fragment carrying the gnt promoter and the gntR gene, the gnt operator was found to be located within a 141-base pair region containing the gnt promoter. Deoxyribonuclease I protection experiments revealed that the gnt repressor protected a gnt promoter region, between -10 and +15, which contains a region showing dyad symmetry with a sequence showing half-symmetry, ATACTTGTA. A 35-base pair synthetic duplex DNA containing this region showing dyad symmetry specifically bound to the gnt repressor. Through cleavage at two AccI sites in the protected region an 8-base pair deletion was introduced into the region showing dyad symmetry, which made expression of the gnt promoter constitutive. A DNA fragment carrying this deletion did not bind to the repressor. These results clearly indicated that the gnt operator sequence is a sequence containing the region showing dyad symmetry located at the transcription initiation site of the gnt operon. It was also suggested that the gnt operon contains only one operator. The similarity in the recognition between the repressor-operator interaction of the gnt operon and those of Escherichia coli TrpR and its operators was discussed.

Amino Acid Sequence↗