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Biomedical subjects

S Hiraga

Publications and source records attributed to S Hiraga.

At least 181 records · Page 10Linked to original sources
PubMed1986

A clinical trial of removal of bilirubin in blood by Evaflux-2A.

We performed both free and albumin-bound bilirubin removal therapy using the Evaflux-2A and evaluated its clinical effects. The removal rates of total bilirubin in the first and second sessions were 31.4%, and 31.0%, respectively. Our clinical data suggested that plasma exchange using Evaflux-2A and an albumin-added electrolyte solution as the substitute fluid was useful in the treatment of hyperbilirubinemia.

Bilirubin↗
PubMed1985

Mechanisms essential for stable inheritance of mini-F plasmid.

The F plasmid has its own partition mechanism and ccd mechanism (coupled cell division), besides its own replication mechanism, in order to be stably inherited into daughter cells through cell division. These 3 mechanisms are independent of one another. Therefore, when a DNA segment essential and sufficient for a mechanism is jointed to other heterologous plasmids, the segment is also functional. Most of natural low copy number plasmids might also have their own replication, partition, and ccd mechanisms. These 3 mechanisms may be fundamental to ensure stable inheritance for low copy-number replicons in prokaryotes.

Bacteriophage lambda↗
PubMed1985

Negative control of oriC plasmid replication by transcription of the oriC region.

We have demonstrated that the replication of the oriC plasmid, carrying the replication origin of the Escherichia coli chromosome, is inhibited by transcriptional readthrough from an oriC flanking region of the plasmid. This was drawn from an examination of the replication of an oriC plasmid, pKZ4, which bears the lacOP segment at the right-hand side of oriC (the asnA side) in such an orientation that transcription from the lac promoter proceeds towards oriC. Replication of pKZ4 was found to be drastically inhibited by inducing transcription from the lac promoter with IPTG, an inducer of the lactose operon. When trp transcription attenuator termination sequences were inserted near the right-hand end of the oriC region of pKZ4, the replication of the plasmid became considerably insensitive to the inhibitory effect of IPTG. This indicates that the inhibition is due to the frequent leftward transcription, which initiates at the lac promoter and proceeds into the oriC region. Since IPTG inhibits the replication of pKZ4, but not that of another coexisting oriC plasmid which is devoid of the lacOP segment, the replication inhibition is judged to act only in cis. Transcription from the promoter of the chloramphenicol resistance gene also caused the inhibition of oriC plasmid replication.

Base Sequence↗
PubMed1985

Effects of the ccd function of the F plasmid on bacterial growth.

The ccd segment of the mini F plasmid containing the ccdA and ccdB genes controls the coordination between plasmid proliferation and cell physiology and fate. When the DNA replication of a thermosensitive-replication plasmid carrying the ccd segment of mini F is blocked, plasmid DNA molecules are progressively diluted through cell division until the copy number reaches 1 per cell. From this time on, there is little increase in the number of viable cells, although cells continue to divide, resulting in a mixed population of viable cells (mostly plasmid containing), nonviable but residually dividing cells, and nonviable nondividing cells. Results are presented suggesting that plasmid-containing cells are viable and continue to divide, whereas plasmid-free segregants are nonviable and form filaments after a few residual divisions, with DNA synthesis reduced or arrested in the filaments. Although the ccd functions are known to induce the SOS response when plasmid replication is blocked, the production of nonviable plasmid-free segregants is independent of the SOS cell division inhibition mechanism determined by the sfiA and sfiC genes.

Cell Division↗
PubMed1984

Prophage lambda induction caused by mini-F plasmid genes.

When bacterial cells harboring a temperature-sensitive replication plasmid, which carries the particular ccd segment (coupled cell division) containing the ccdA and ccdB genes of a mini-F plasmid, are transferred to 42 degrees C, cell division is inhibited after incubation for an appropriate time. The inhibition occurs, when the copy number of the plasmid decreases to become critically low, about one per cell (Ogura and Hiraga 1983b). In lambda phage lysogens carrying this type of plasmid, the prophage is induced in a small portion of the cell population under the same conditions, in addition to the inhibition of cell division in most of cells. The prophage induction, but not the inhibition of normal cell division, depends on normal recA function. Both induction of prophage and inhibition of cell division are suppressed by the simultaneous presence of a replication proficient plasmid carrying the ccdA gene. We discuss molecular mechanisms of the ccd function that couples host cell division to plasmid proliferation and induces the prophage. Additionally, we propose a hypothesis that the ccd mechanism of F plasmid contributes to indirect induction of prophage lambda by an F plasmid damaged by UV-irradiation and then introduced into a lysogen via conjugation.

Bacteriophage lambda↗
PubMed1984

Molecular cloning of the phosphoenolpyruvate carboxylase gene, ppc, of Escherichia coli.

The ColE1 hybrid plasmid, pLC20-10, carrying the ppc gene and the argECBH gene cluster of Escherichia coli K-12, was characterized. The ppc gene coding for phosphoenolpyruvate carboxylase (EC 4.1.1.31), was subcloned into the plasmid pBR322 to give the plasmids pS2 and pS3. These plasmids carried a 4.4-kb SalI segment containing the ppc gene, in both orientations. The specific activity of the enzyme was increased approx. 20-fold by these plasmids. Experiments with maxicells harboring pS2 showed that the 90-kDal enzyme subunit was encoded by the plasmid. The location of the ppc gene in pS2 and the direction of transcription of the gene were determined. In DNA-DNA hybridization experiments using pS2 as a probe, significant hybridizations were observed with DNAs from E. coli strains K-12 and W, and from Salmonella typhimurium, but not with those from Chlorella regularis, Anacystis nidulans, Rhodospirillum rubrum, and Pseudomonas AM-1.

Bacteria↗
PubMed1984

[Perineal testis: report of two cases].

Perineal testis is a very rare congenital anomaly. Since the first case of the disease reported by John Hunter in 1786, more than 113 cases have been reported in the English literature, and 13 cases have been reported in the Japanese literature. The 14th and 15th cases are presented herein. Case 1 was a 38-year-old man who came to our clinic with the chief complaint of discomfort of the perineum. Physical examination revealed emptiness of the left scrotal contents and there was a small hen's-egg growth mass corresponding to the normal testis at the left side of the perineum. Excretory urogram showed no abnormality. Orchiopexy to the left scrotum was performed. On surgical exploration the gubernaculum testis was found obviously fixed to the perineum. Histologic examination of the biopsied ectopic testis revealed mild hypospermatogenesis. Case 2 was a 2-year-old boy who was referred to our clinic with the chief complaint of emptiness of the right scrotal contents. Physical examination revealed a bean-sized mass corresponding to the normal testis at the right side of the perineum. Orchiopexy to the right scrotum was performed. On surgical exploration the gubernaculum testis was found to be fixed to the perineum.

Adult↗
PubMed1984

[Cirsoid intrarenal arteriovenous malformation. Report of 2 cases, with special reference to review of 74 cases in Japan].

Two cases of cirsoid intrarenal arteriovenous malformation, in a female aged 67 and in a male aged 18, are reported and 74 cases of the same disease collected from the Japanese literature are reviewed. Several classifications have been proposed for the so-called congenital renal arteriovenous fistula. A truly congenital form of the lesion, however, is considered to be cirsoid type and we collected only this type of arteriovenous malformation. The number of reported cases has been increasing annually. The age distribution ranged from 10 to 84 years old (mean: 38.1 years old); 49 were female and 19 male. Gross hematuria, bladder tamponade and flank pain, which can be called the triad of cirsoid intrarenal arteriovenous malformation accounted for 84.0% of the clinical symptoms, whereas cardiovascular signs and symptoms accounted for only 7.8%. The right kidney was most frequently diseased and the intrarenal lesions showed about the same distribution in the upper pole, in the middle region and in the lower pole. Pathogenetic and pathophysiologic aspects of the renal arteriovenous malformation were discussed. Renal angiography is the most helpful method for obtaining a definite diagnosis, while such findings on the intravenous pyelogram as the so-called cobble stone deformity are thought to be characteristics of the X-ray. For the treatment of cirsoid arteriovenous malformations, conservative therapies including administration of styptics were carried out in 13%, selective transcatheter embolization in 17% and surgical procedures in 70%. The recent number of transcatheter embolization has been increased to establish it as one of the distinct therapeutic methods for this disease. Among the operative methods, partial nephrectomy is now being used more than nephrectomy and 4 cases of ex vivo surgery have been reported recently in Japan.

Adolescent↗
PubMed1984

[Stones of the seminal vesicles and ejaculatory duct in infant: report of a case].

A 7-year-old boy was brought to our clinic with the chief complaint of terminal pain on urination. Rectal examination revealed a prostate of almost normal size and consistency, but seminal vesicles were palpated to be hard and in a painful mass. Plain x-ray and urethrogram demonstrated several small stones in the posterior urethra and in seminal vesicles. In the first operation, the stones located in the posterior urethra were removed through the transvesical approach, and the seminal vesicular stones were extirpated in the next operation. The stones were found to consist of magnesium ammonium phosphate by infrared rays spectrum analysis. The histopathological findings of the partially resected seminal vesicles showed no inflammatory or tuberculous changes. Twenty cases of stones in seminal vesicle, in seminal canal, or in ejaculatory duct have been reported in the Japanese literature. Etiology, pathology, clinical problems and therapy of the stones of seminal tract are discussed in relation to the cases reported in Japan including the present case.

Calculi↗
PubMed1983

Novel form of DNA polymerase alpha associated with DNA primase activity of vertebrates. Detection with mouse stimulating factor.

With a specific stimulating factor of mouse DNA replicase for its detection, a novel form of DNA polymerase alpha (DNA replicase) associated with DNA primase activity was partially purified from several vertebrates, i.e. the cherry salmon Oncorhyncus masou, the frog Xenopus laevis, the chick, and human (HeLa cells). Activity similar to DNA replicase was also partially purified from embryos of the sea urchin Anthocidaris crassispina. In all vertebrates examined, two forms of DNA polymerase alpha were separated by chromatography on ion-exchange columns; one form (DNA replicase) was associated with DNA primase activity and could utilize unprimed single-stranded DNAs as template, and the other could not utilize unprimed single-stranded DNAs. The sedimentation coefficient of the former, the novel form, obtained from each vertebrate in a glycerol gradient at high ionic strength was slightly larger than that of the other form which had no primase activity, except in the case of chick embryos where the sedimentation coefficients of the two forms were almost the same. The initiator RNA synthesized with the DNA primase activity associated with DNA replicase obtained from salmon, chick, HeLa cells, and sea urchin was 8 to 10 nucleotides long. The stimulating factor obtained from Ehrlich ascites cells has been found to stimulate both the activities of DNA primase and DNA polymerase in DNA replicase obtained from all the vertebrates examined, when unprimed single-stranded DNA was used as template, while the factor failed to stimulate both the activities of the enzyme of sea urchin embryos. This factor thus should be an effective tool in studies on the mechanism of vertebrate DNA replication.

Animals↗