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Biomedical subjects

Y Asai

Publications and source records attributed to Y Asai.

At least 145 records · Page 8Linked to original sources
PubMed1996

[A patient with lung metastasis of medulloblastoma].

A 15-year-old boy had metastasis to the spinal cord and then to the lung after an operation to remove a primary medulloblastoma. A medulloblastoma developed at the age of 10 years. The tumor was completely resected and the brain and spinal cord were irradiated. At the age of 13 years, metastasis to the sacral spinal cord developed and was treated with radiotherapy and intramedullary injection of methotrexate. At the age of 15 years, metastasis to the lung developed and was treated with chemotherapy (CBDCA, VP-16) followed by radiotherapy. Three months after the end of that therapy, the disease recurred but another course of radiotherapy and chemotherapy (VCR) was successful. Chemotherapy and radiotherapy were effective against metastatic lesions of medulloblastoma. With improvement in the survival rate among patients with medulloblastoma, we can expect incidence of extraneural metastases to increase. In addition to recurrence of the primary lesion and intramedullary dissemination, these metastatic lesions also require attention.

Adolescent↗
PubMed1995

Isolation of promoters from Brevibacterium flavum strain MJ233C and comparison of their gene expression levels in B. flavum and Escherichia coli.

A promoter probe shuttle vector suitable for the isolation of promoter elements from coryneform bacteria was constructed. This vector carried the neomycin phosphotransferase (NPTII) gene from transposon Tn5 as a reporter gene, and was capable of replication in both Escherichia coli and Brevibacterium flavum. The vector was used in the construction of a B. flavum library of 899 independently isolated promoter clones. Promoters with a wide range of activities in B. flavum, including some very strong promoter elements, were isolated. Comparative analysis suggests that significant differences between B. flavum and E. coli may exist in the determinants of promoter strength.

Base Sequence↗
PubMed1995

Cloning and sequence determination of the aspartase-encoding gene from Brevibacterium flavum MJ233.

A 2.5-kb EcoRI fragment containing the aspartase-encoding gene (aspA) of Brevibacterium flavum MJ233 was cloned into plasmid pUC18 using Southern hybridization with the Escherichia coli aspA gene as a probe. The complete nucleotide (nt) sequence of the cloned DNA indicated that the deduced gene product of the Br. flavum aspA is composed of 526 amino acids (aa). Comparison of the aa sequence to the corresponding sequences from E. coli, Bacillus subtilis and Pseudomonas fluorescens revealed 63, 47 and 57% homology, respectively. The aspA product was determined to have a size of approx. 57 kDa by SDS-PAGE.

Amino Acid Sequence↗
PubMed1995

Inhibition by beraprost sodium of thrombin-induced increase in endothelial macromolecular permeability.

Effect of beraprost sodium (BPS), a long-acting and orally active stable analogue of PGI2, on the macromolecular permeability of cultured vascular endothelial cells (HUVEC) was detected by the transport of FITC-albumin. Thrombin treatment resulted in induction of FITC-albumin transport across the endothelial cell monolayer. The albumin transport induced by thrombin was not accompanied by any damage to the cells. BPS had no effect on the permeability of resting endothelial monolayers, while BPS inhibited the thrombin-induced increase in the albumin permeability in a dose-dependent manner (30-1000 nM). Treatment of the cells with PGI2 or dibutyryl cAMP caused a significant inhibition of the thrombin-induced increase in the albumin permeability. These results strongly suggested that BPS suppressed the thrombin-induced macromolecular permeability in HUVEC through the elevation of its intracellular cAMP, and that BPS was a suppressor against inflammatory vascular changes such as exudation.

Biological Transport↗
PubMed1995

Time course of appearance of ofloxacin in human scalp hair after oral administration.

The time course of appearance of antimicrobial ofloxacin (OFLX) in human scalp hair was monitored in three healthy male volunteers after the oral administration of 100 mg OFLX three times daily for 2 consecutive days. Hair samples were collected from each subject by plucking several strands of frontal hair every day from 1 till 16 days after administration. A single hair was dissolved in 1 M NaOH to extract OFLX by chloroform, and the drug was measured by high-performance liquid chromatography and fluorescence detection. OFLX started to appear in the hair 1 to 3 days after administration and reached the maximal level approximately 4 to 9 days, remaining at almost the same level thereafter. This finding suggests the slow transfer of OFLX from hair follicle cells to hair matrix may be due to the slow dissociation of OFLX from bound melanin.

Administration, Oral↗
PubMed1995

Role of transforming growth factor-beta 1 on platelet-induced enhancement of endothelin-1 production in cultured vascular endothelial cells.

We and other investigators obtained evidence that platelets stimulate endothelin-1 (ET-1) production at both message and protein levels in vascular endothelial cells (ECs), and that platelet-derived transforming growth factor-beta 1 (TGF-beta 1) is responsible for this stimulation. In the present study, we examined the effects of acidification or heat treatment, known to activate latent TGF-beta 1, on the platelet supernatant-induced ET-1 production in cultured porcine aortic ECs. Supernatant of platelets (6.0 x 10(8) platelets/ml) aggregated by adenosine diphosphate contained large amounts of TGF-beta 1, but were almost in a latent form, and the proportion of active TGF-beta 1 in the supernatant was increased markedly in the case of acidification or heat treatment. These treatments also significantly potentiated the supernatant-induced stimulation of prepro ET-1 mRNA expression and the ET-1 release in ECs. Purified TGF-beta 1 also enhanced ET-1 release, dose-dependently, but the enhancement declined at the higher concentrations. Thus, powerful stimulation of ET-1 production by platelet supernatant after acidification or heat treatment cannot be explained only by increments in active TGF-beta 1. The supernatant-induced stimulation of ET-1 synthesis was significantly inhibited by concomitant treatment of TGF-beta 1 neutralizing antibody, but this inhibition was incomplete even at a concentration that abolished TGF-beta 1-induced maximal stimulation. These results suggest that platelet-induced stimulation and subsequent acidification and heat treatment-induced potentiation on endothelial ET-1 production depend closely on release and activation of TGF-beta 1 derived from platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Long-term mechanical ventilation in Japan, with special reference to home mechanical ventilation].

Some patients in respiratory care units are difficult to wean from mechanical ventilation, and may be candidates for home mechanical ventilation (HMV). HMV may improve these patients' quality of life and decrease medical expenses. Since 1987, six nationwide questionnaire surveys were done to study the status of long-term mechanical ventilation (defined as mechanical ventilation for at least 90 days) and HMV in Japan. In 1994, an additional questionnaire regarding opinions about HMV was sent to physicians, patients undergoing HMV, their families, and people in companies that deal with home ventilators. From 1987 to 1994, the number of patients who had been mechanically ventilated for at least 90 days increased from 368 to 956. According to the 1994 survey, 565 of those patients were not candidates for HMV, 235 of them were candidates for HMV but could not be shifted (reasons are given below), and 156 were shifted to HMV. The reasons that some patients who were considered to be candidates for HMV could not be shifted included a lack of caregivers at home (58.1%), the cost of a ventilator (44.5%), lack of proper health insurance (39.8%), problems with ventilator maintenance and delays in obtaining repairs (37.7%), and inadequacies in the system for providing medical care in the home (33.1%). Despite the problems entailed in shifting to HMV, many patients undergoing HMV (77.8%) and members of their families (83.3%) expressed a desire to continue this therapy. Many physicians (94.0%) said they believed that HMV improves the quality of life of patients with chronic respiratory failure. Some companies intend to begin renting ventilators for HMV. The use and development of HMV in Japan would be promoted if the national health insurance covered the costs of this therapy.

Chronic Disease↗
PubMed1994

Transposon mutagenesis of coryneform bacteria.

The Corynebacterium glutamicum insertion sequence IS31831 was used to construct two artificial transposons: Tn31831 and miniTn31831. The transposition vectors were based on a gram-negative replication origin and do not replicate in coryneform bacteria. Strain Brevibacterium flavum MJ233C was mutagenized by miniTn31831 at an efficiency of 4.3 x 10(4) mutants per microgram DNA. Transposon insertions occurred at different locations on the chromosome and produced a variety of mutants. Auxotrophs could be recovered at a frequency of approximately 0.2%. Transposition of IS31831 derivatives led not only to simple insertion, but also to cointegrate formation (5%). No multiple insertions were observed. Chromosomal loci of B. flavum corresponding to auxotrophic and pigmentation mutants could be rescued in Escherichia coli, demonstrating that these transposable elements are useful genetic tools for studying the biology of coryneform bacteria.

Base Sequence↗
PubMed1994

Cloning and sequencing of the secY homolog from Coryneform bacteria.

A conserved domain of the secY genes from Bacillus subtilis, Mycoplasma capricolum and Escherichia coli was used to design degenerate oligodeoxyribonucleotides. These synthetic DNA sequences were used to screen a lambda library of Brevibacterium flavum MJ233. A 1.5-kb KpnI fragment of a recombinant lambda phage containing the secY homology from Br. flavum MJ233 was subsequently subcloned into plasmid pUC118. The complete nucleotide (nt) sequence of the cloned fragment indicated that the deduced gene product of the Br. flavum secY homolog is composed of 440 amino acids (aa) with a deduced M(r) of 47,871. Comparison of this aa sequence to the corresponding sequences from E. coli and B. subtilis revealed a high degree of conservation, and suggested that the Br. flavum secY homolog is a membrane protein containing ten transmembrane segments. In addition, we could identify, downstream from secY, a putative coding sequence of the enzyme adenylate kinase. This gene organization is identical to that observed in the B. subtilis genome.

Actinomycetales↗
PubMed1994

Computed tomography of the temporal bone in tuberculous otitis media.

Nine cases of tuberculous otitis media were treated by us over the past 10 years. Six patients presenting with large tympanic membrane perforations were treated for suppurative otitis media at various ENT clinics. The remaining three patients presented without perforation. Intractable otorrhoea, aggravation of hearing loss, dizziness, and in one case facial palsy, resulted in eventual referral to us. Histological examination revealed a tuberculous granulation, confirming the diagnosis in most cases. CT in four cases with profound sensorineural hearing loss showed bone destruction of the otic capsule around the oval window and the promontory. Changes noted included a notch in one case, disappearance of the bony contour around the hook in two cases, and a distinct fistula in the final case. A cochlear fistula seemed to be characteristic of advanced tuberculous otitis media.

Aged↗
PubMed1994

[Application of urine sediment for diagnosis of gonococcal urethritis by enzyme immunoassay].

We evaluated the usefulness of urine sediment from male gonorrhea patients for detecting gonococcal antigens by enzyme immunoassay, Gonozyme (Abbott Laboratories). Experiments for dilution rate of urine sediment with buffer provided in a kit indicated that dilution of sediment at 1:4-6 would be practical in performing Gonozyme. All urine sediment specimens from 18 gonorrhea patients showed positive by Gonozyme, and 68, except for 3, culture-negative control urine sediments, including 8 sediments from patients with chlamydial urethlitis, were negative. Based on comparing results of Gonozyme with those of culture, sensitivities and specificity were 88.9-100% and 95.6%, respectively. During storage of urine sediment at 5 degrees C for 7 days, absorbance values were stable. Therefore, urine sediment could be preserved or transported. We conclude that urine sediment is useful for diagnosis of gonococcal urethritis in males by Gonozyme.

Antigens, Bacterial↗
PubMed1994

[Transurethral hyperthermic treatment in patients with benign prostatic hypertrophy].

Transurethral hyperthermic treatment was performed on 30 patients with benign prostatic hypertrophy (BPH). Two patients had a urethral catheter because of urinary retention. The prostate was heated transurethrally. The treatment consisted of 3-8 sessions of 60 min. each. To evaluate this treatment, the following parameters were determined before and 1-5 weeks after the last hyperthermia session; subjective symptoms score, and as objective data residual urine volume and uroflowmetry. The symptoms score improved in 25 (83%) patients. Of 2 patients with a catheter, the catheter could be removed from 1 patient. Although there was no change in prostatic volume, significant decreases in residual urine volume, and increases of maximum flow rate and mean flow rate were observed. No adverse reactions were seen. Judging from the above results, this treatment is considered to be useful for patients with BPH.

Aged↗
PubMed1994

[Bladder hernia: report of two cases].

Case 1. A 55-year-old male visited our hospital complaining of dysuria and two-staged micturition. Physical examination revealed a fist sized, elastic soft mass in the left inguinal region. Upright drip infusion pyelography (DIP) showed left inguinal hernia of the bladder. Retrograde urethrography showed bladder neck contracture and a diverticulum. Cystoscopy revealed a indentation in the left bladder wall. Urodynamic studies demonstrated organic obstruction in the lower urinary tract. From these findings, diagnosis was made as bladder hernia and bladder neck contracture. Resection of thin portion of the bladder wall and hernia repair, accompanied by prostatectomy, was performed. Case 2. A 37-year-old male visited our hospital with the history of ureteral stone and chronic prostatitis. Upright DIP incidentally revealed the small right inguinal bladder hernia. Because he had no complaint of dysuria and two-staged micturition, he was observed without surgical treatment.

Adult↗
PubMed1993

Regulation of hsp70 induction in thermotolerant HeLa cells.

Upon exposure to heat shock, non-thermotolerant (NT) HeLa cells transiently synthesize a large amount of 70-kDa heat-shock protein (hsp70), whereas thermotolerant (TT) cells synthesize a small amount of hsp70. When the hsp70 mRNA of HeLa cells was analyzed, it became apparent that hsp70 mRNA in TT cells did not increase following heat shock, whereas hsp70 mRNA in NT cells did increase dramatically. A further analysis of the activation of the heat-shock transcription factor (HSF) showed that significant activation of HSF was observed immediately after heat shock in both NT and TT cells. However, activated HSF was rapidly repressed in the TT cells, but not in the NT cells. Thus, the decreased induction of hsp70 synthesis observed in the TT HeLa cells may be due to the immediate repression of activated cellular HSF, which probably results in the reduced induction of hsp70 mRNA. The hsp70 content in the TT cells was usually higher than in the NT cells. However, after heat-shock treatment, the hsp70 content of the NT cells increased to nearly the level of the TT cells concomitant with the repression of hsp70 synthesis. The association of activated HSF with hsp70 was observed in both NT and TT cells, and the amount of HSF-hsp70 complex within the cell increased in proportion to the increase in hsp70 in the cells. These findings strongly suggest that the activity of HSF is negatively regulated by the intracellular content of hsp70 in these cells. Furthermore, in vitro experiments on the activation of HSF suggest that HSFs of NT and TT cells may have different properties, or an unknown factor may exist which regulates HSF activation in these cells.

Base Sequence↗