Biomedical subjects

S Tabata

Publications and source records attributed to S Tabata.

At least 235 records · Page 13Linked to original sources

PubMed1984

Replication and nicking of zygotene DNA sequences. Control by a meiosis-specific protein.

A protein having a molecular weight of 73,000 daltons has been purified from the nuclear membranes of preleptotene, leptotene, and zygotene cells. It has been named the leptotene protein (L-protein) because of its role in suppressing the replication of zygotene DNA sequences through leptotene until the initiation of zygotene DNA synthesis. The protein has been found to be highly specific in its inhibitory activity. S-phase replication in somatic nuclei and in microspore nuclei are unaffected by the protein. Only zygotene DNA sequences appear to be affected. L-protein binds specifically to zygotene DNA. The binding is limited to a relatively short DNA segment, probably no longer than 90 base pairs (bp). Chloroplast and mitochondrial DNA do not bind to the protein, but a low level of binding is displayed by DNA from several other eukaryotic species. The L-protein also has the capacity to nick the bound DNA in the presence of ATP. Nicking does not occur in the absence of binding. Using supercoiled plasmids with zygotene DNA inserts as substrates, the nicking has been found to be confined to a small region of the plasmid and to occur in only one of the strands. The L-protein is considered to be one of the principal factors responsible for the irreversible commitment of cells to meiosis at the end of the preleptotene S-phase. It is also proposed that its endonucleolytic activity plays a role in the initiation of synapsis.

Cell Cycle Proteins↗

PubMed1984

[Experience of renal autotransplantation].

We present 2 cases with renovascular hypertension treated by renal autotransplantation and 3 cases with extensive renal calculi treated by renal bench surgery and autotransplantation. The cases with renovascular hypertension were due to fibromuscular dysplasia in the trunk of renal artery, and return to normotension and improvement of renal function were obtained within a few days after the operation. In 2 of the cases with extensive renal calculi, the contralateral kidney was contracted. In all cases, the stones were removed completely and urinary tract infection persisting before operation was eradicated. The postoperative renal function was well preserved and no recurrence of renal calculi was observed throughout the follow up period. The indication of renal bench surgery and autotransplantation was discussed both for renal calculi and renovascular hypertension.

Adult↗

PubMed1984

[Central nervous system irradiation for children with leukemia].

Between 1972 and 1981, 247 patients with acute lymphoblastic leukemia were treated with prophylactic CNS irradiation. Cranial irradiation (2400 rad) plus intrathecal methotrexate was the prophylactic CNS therapy of choice. At 5 years, the overall, relapse-free and CNS relapse-free survival rates were 51%, 47% and 79%, respectively. Our findings suggest that more attention should be paid to the inferior border of the radiation field, since the anterior and middle cranial fossae were sometimes not included and the second spine was almost always excluded.

Adolescent↗

PubMed1984

[A clinical observation on pyeloplasty in obstruction of the ureteropelvic junction. Special consideration on Anderson-Hynes pyeloplasty].

Thirty-three patients (thirty-five kidneys) underwent pyeloplasty for hydronephrosis due to obstruction of ureteropelvic junction between 1963 and 1982 in our department. Renal function was judged to have improved in 68 and 67% of the patients from the radiogram and radioisotope renogram, respectively, Anderson-Hynes pyeloplasty was performed on 27 kidneys. In these kidneys, the improvement of renal function as judged from the radiogram and radioisotope renogram was 74 and 71%, respectively. Postoperative results were compared according to age, preoperative urinary tract infection (UTI), indwelling periods of nephrostomy and splint catheter, and duration of postoperative UTI. In addition the relationship between indwelling periods of nephrostomy catheter and the duration of postoperative UTI are discussed. Infants under 10 years old had the best improvement. Preoperative UTI and indwelling periods of nephrostomy and splint catheter were not directly related with post operative results. The cases with nephrostomy catheter which could be removed within the 16th day after operation had excellent improvement on UTI and also in renal function.

Adolescent↗

PubMed1984

[Clinical study of lumbar spinal canal stenosis on 70 operated cases --clinical symptoms, pathogenesis, operative method, postoperative results].

In surgical treatment of lumbar spinal canal stenosis, the stenotic area related to the clinical symptoms was determined and the stenotic form and stenotic factors in this stenotic area were estimated before operation. The most appropriate decompression of the stenotic area was performed taking the stenotic form into consideration and retaining the spinous process and interspinous ligament. In cases of stenosis of the spinal canal, posterolateral decompression of the dural sheath was performed by means of resection of the medial edge of the bilateral inferior articular processes and the yellow ligaments. In cases of stenosis of the spinal canal associated with stenosis of the lateral recess, the root was decompressed by unroofing the lateral recess in addition to posterolateral decompression of the dural sheath. And in cases with stenosis of the lateral recess, the root in an affected area was decompressed. Neither operation on the intervertebral disc nor incision of the dural sheath was performed. After operation as described above, symptoms, operative findings and postoperative results were investigated in 70 cases which could be directly examined. In this paper we discuss the relationship between the symptoms and the stenotic area, stenotic forms and stenotic factors. When our postoperative results were compared with those of cases with extensive laminectomy, it was seen that none of the patients we treated had low back pain nor recurrence of intermittent claudication and that lessening of paralysis was sufficient.

Adult↗

PubMed1984

Rapid induction of carcinoma in situ in dog urinary bladder by sequential treatment with N-methyl-N'-nitrosourea and N-butyl-N-(4-hydroxybutyl)-nitrosamine.

A highly atypical intraepithelial proliferation, which was interpreted as carcinoma in situ, developed in the urinary bladder of 2 beagle dogs after repeated intravesical instillations of N-methyl-N'-nitrosourea followed by oral administration of N-butyl-N-(4-hydroxybutyl)nitrosamine. The latent period was 37 weeks. The technique may provide a useful model to study the natural history of bladder cancer, particularly carcinoma in situ.

Animals↗

PubMed1983

The 245 base-pair oriC sequence of the E. coli chromosome directs bidirectional replication at an adjacent region.

The replication origin of the E. coli K-12 chromosome has been isolated as autonomously replicating molecules(oriC plasmid), and the DNA region essential for replicating function(oriC) has been localized to a sequence of 232-245 base-pairs(bp) by deletion analysis. In this report, the functional role of oriC was analysed by using an in vitro replication system and various OriC+ and OriC- plasmids previously constructed. The results obtained were summarized as follows: (1) The oriC sequence contained information enough to direct bidirectional replication. (2) The actual DNA replication began at a region near, but outside, oriC and progressed bidirectionally. (3) Initiation of DNA synthesis at the specific region required the dnaA-complementing fraction from cells harboring a dnaA-carrying plasmid.

Base Sequence↗

PubMed1983

[Epidemiological and therapeutic studies of gonorrheal infections (I)--clinical efficacy of long acting amoxicillin (L-AMPC)].

During the period from October of 1981 through March of 1982, our research group in Sapporo treated 178 patients (158 males and 20 females) for gonorrheal infections. We performed epidemiological and therapeutic studies on these patients. The youngest of the 158 male patients with acute gonorrheal urethritis was 15 years old. The age distribution was 32 patients (20.3%) under 20 years, 46 patients (29.1%) aged 20 to 24, 34 patients (21.5%) aged 25 to 29, 22 patients (13.9%) aged 30 to 34, 10 patients (6.3%) aged 35 to 39, and 14 patients (8.9%) aged 40 to 54. The fact that 20% of gonorrheal urethritis occurred in youths under 20 years of age, is especially noteworthy. The infection in the teenage boys was found to be picked up mostly from girls met at discos , etc., On the other hand, the patients in their 20s, were infected more frequently by contact with hostesses at massage parlors and bars, these sources making up the majority of male patients who were 25 years or older. These findings are quite interesting because they reflect the socio-economic status of the patients. In addition, the fact that hostesses working at massage parlors are a frequent source of gonorrheal urethritis infections can represent a considerable problem in terms of public hygiene. The 20 female patients with gonorrheal infections were all found to be cases of cervicitis, except for a 1-year-old girl with gonorrheal infection of external genitals. The fact that about half of these female patients were teenagers, aged 16 to 19 years is worth special note. The duration of the latent period was less than 5 days in 83 male patients (58.9%) with urethritis, 6 approximately 10 days in 39 patients (27.7%), 11 approximately 20 days in 13 patients (9.2%), 21 approximately 30 days in 4 patients (2.8%), and over 30 days in 2 patients (1.4%), It can thus be said that the number of cases showing a long incubation period is increasing. The MICs of 154 gonococci strains isolated from the urethral or vaginal discharge were determined. Thirteen (8.4%) of these clinically isolated strains were found to be beta-lactamase producers. When a bacterial inoculation level of 10(6) cells/ml was used in the in vitro MIC determination, the MIC was 1.56 micrograms/ml or higher for 12 of these beta-lactamase-producing strains; the MIC of the 13th strain was 0.78 microgram/ml. At the same time, the MICs of these beta-lactamase-producing strains to doxycycline were also high; 1.56 micrograms/ml or higher.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1981

Nucleotide sequences of the 5S ribosomal RNA genes and their adjacent regions in Schizosaccharomyces pombe.

The organization of 5S ribosomal RNA (rRNA) genes in the genome of Schizosaccharomyces pombe has been investigated by restriction and hybridization analyses. The 5S rRNA genes were not linked to the other three species of rRNA genes which formed a repeating unit of 6.9 megadaltons, but located in other regions surrounded by heterogeneous sequences. The 5S rRNA gene organization in S. pombe is therefore different from those in other yeasts; Saccharomyces cerevisiae and Torulopsis utilis. Four restriction segments of different sizes each containing a single 5S rRNA gene were cloned on a bacterial plasmid, and the sequences in and around the RNA coding regions were determined. In the RNA coding regions, the sequences in four clones were identical with an exception that one residue has been substituted in one clone. In the flanking regions, the sequences were extremely rich in the AT-content and highly heterogeneous. The sequences were also markedly different from those in the corresponding regions of the other two yeasts. THe presence of T-clusters in the regions immediately after the RNA coding sequences was only notable homology among the four clones and the other two yeasts.

Ascomycota↗

PubMed1980

Structure of the 5-S ribosomal RNA gene and its adjacent regions in Torulopsis utilis.

A DNA segment spanning one repeating unit of ribosomal RNA(rRNA) genes in a yeast strain, Torulopsis utilis, has been cloned on a bacterial plasmid pBR322. The size of the cloned segment was about Mr = 8.0 x 10(6). All of the genes for the four species of rRNA were linked on it, and there was a long spacer between the 5-S and 18-S rRNA coding regions. The nucleotide sequences of the regions flanking the 5-S rRNA gene were determined and compared with those in the corresponding regions of Sacharomyces cerevisiae [Valenzuela, P., Bell, G. I., Masiarz, F. R., DeGennaro, L. J., and Rutter, W. J. (1977) Nature, 267, 641-643; Maxam A. M., Tizard, R., Skryabin, K. G., and Gilbert, W. (1977) Nature, 267, 643-645]. The sequence of the T. utilis 5-S rRNA is identical with that of S. cerevisiae except for two residues at positions 18 and 61. However, its upstream region contained a quite different sequence, and a sequence which showed some homology was only found at positions -21 to -28. The sequences were d(T-G-T-A-A-C-C-T) in T. utilis and d(T-A-T-C-A-C-C-T) in S. cerevisiae. Although the presence of various repeat sequences having the same or opposite directions was noted, these repeats occurred at different positions in the two yeast species. In the downstream region, the common sequence was only seven dT deoxynucleotides, which occurred immediately after the 5-S rRNA coding sequence. Significant direct and inverted repeat sequences were found in T. utilis, but such repeats are not seen in S. cerevisiae.

Base Sequence↗

PubMed1979

The clustered and scrambled arrangement of moderately repetitive elements in Drosophila DNA.

An examination of cloned Drosophila DNA has revealed large clusters of densely spaced, short (less than or equal to 1 kb), moderately repetitive elements. Different clusters have many of the same repetitive elements, but these elements are arranged differently in each cluster. It is improbable that this clustered arrangement can be detected by conventional reassociation kinetic and electron microscopic techniques, but it can be detected and features of its fine structure can be determined by a two-dimensional version of Southern's blotting technique. The genomic organization of these clustered repetitive elements was investigated by hybridizing restriction fragments of cloned DNA to polytene chromosomes, to filter-bound recombinant DNA clones and to Southern blots of total Drosophila DNA. These studies demonstrated that clusters occur in euchromatic regions of the chromosomes and that at least one of the clusters has the same repetitive element organization in cloned and in chromosomal DNA. These studies also demonstrated that copies of the elements from one cluster are scattered in at least 1000 chromosomal regions. These regions appear to have differing concentrations of repetitive DNA, but together they account for a large fraction of Drosophila's moderately repetitive DNA. Aside from indicating the genomic organization of cluster elements, this work has identified cluster elements throughout a 9 kb region neighboring one of the heat shock genes, throughout the intron of the major rDNA repeat and within the apparently transposable element, 412.

Animals↗

PubMed1973