Search PubMed⌕ Search

Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 379 records · Page 21Linked to original sources
PubMed1993

Molecular cloning of a unique complementary DNA of rat myosin regulatory light chain and its elevated expression in v-src-transformed rat culture cell lines.

We have isolated a complementary DNA (cDNA) clone, termed N14, from a cDNA library derived from normal rat fibroblast 3Y1 cells using a differential screening procedure. N14 cDNA was 1115 nucleotides in length and contained an open reading frame of 172 amino acid residues. The expression of N14 gene was significantly increased in Rous sarcoma virus-transformed 3Y1 cells (SR-3Y1) compared with that in parental 3Y1 cells. The high level of N14 gene expression was reduced by treatment with herbimycin A, indicating that the expression was dependent upon the activity of pp60v-src tyrosine kinase. A homology search revealed that the nucleotide sequence of N14 cDNA was nearly identical to that of the rat nonsarcomeric myosin regulatory light chain cDNA (RLC-B), with the exception of a 250-nucleotide insertion which is present between C at position +483 and G at position +484 in the RLC-B cDNA. Southern blot analysis indicated that N14 gene was present as a single copy in the rat genome. Therefore, these two mRNAs might be generated through the alternative splicing mechanism. However, a RNase protection assay revealed that RLC-B mRNA was not expressed in SR-3Y1 cells. In addition, the amount of N14 mRNA was also increased in other types of transformed cells, including v-mos-, simian virus 40-, and v-Ha-ras-transformed 3Y1 cells.

Alternative Splicing↗
PubMed1993

[Serum thrombomodulin levels in patients receiving allogeneic bone marrow transplantation].

It has been reported that serum levels of thrombomodulin (TM) reflect endothelial damages in various diseases. We measured serum TM levels between day-10 and day 100 in 6 patients receiving allogeneic bone marrow transplantation. Serum TM levels were increased when patients had transplant related complications including graft versus host disease, hemorrhagic cystitis and interstitial pneumonitis. In patient without complications, serum TM levels were within normal limits. These results suggest that the serum TM level serves as a useful marker of treatment related toxicity and a predictor of complications after BMT.

Adult↗
PubMed1993

[One stage operation for dead space of pyogenic and tuberculous osteomyelitis].

Pyogenic and tuberculous osteomyelitis is known to have difficult surgical problems. Complete surgical excision of dead and grossly infected soft tissues and osseous structures frequently results in large defects. Hydroxyapatite filler has been used to pack osteomyelitic defects. Between 1984 and 1991 we have treated 6 foci in 6 patients: 4 males aged 61, 54, 47 and 26 and; 2 females aged 59 and 36 years. There were 3 cases of chronic osteomyelitis, and one each of acute osteomyelitis, tuberculous osteomyelitis, and Brodie's abscess. All were reviewed within a period of between 21 to 94 months postoperatively. The pathogens cultivated were Mycobacterium tuberculosis in case 2 and Staphylococcus aureus in case 3 and case 6. In other cases, cultures revealed no pathogens. The hydroxyapatite fillers were mixed with an antibiotic. In addition, in the last four cases the fibrin sealant and CaCl2-thrombin solution were mixed. The excavated bone defect was packed with this composite biomaterial. Neither closed irrigation/suction using antibiotic solution nor a cast was used. Antimicrobial therapy directed specifically to the deep tissue specimens, was administered to all patients. On examination, all of the foci had completely healed by the end of the follow-up period. The cure of pyogenic and tuberculous osteomyelitis is obtained from obliterating dead spaces, which prevent the survival of organisms. Hydroxyapatite is the biomaterial most compatible with human bone and is also suitable for obliterating dead space. The advantages of the fibrin sealant system are that defects can be packed without gaps. Thus, postoperative hematomas can be avoided. In addition, the antibiotic incorporated into the fibrin sealant is released more slowly from the concentrated fibrin than from hematomas. As a result, pathogens multiply more slowly in fibrin. From these findings, we believe that this new method is simple, can be performed safely in one stage, and offers satisfactory results.

Adult↗
PubMed1993

[Cyclosporine-induced graft-versus-host disease in a syngeneic bone marrow transplantation].

A 33-year-old woman with AML (M4) resistant to chemotherapy received syngeneic marrow graft from her identical twin following high dose busulfan and etoposide. However, the relapse was confirmed on the 60th day after the procedure. Since she failed to achieve remission despite intensive chemotherapy, a second BMT from the same donor was performed following total body irradiation and high dose etoposide on the 126th day after the initial BMT. At this time, cyclosporine (1 mg/kg/day) was administered to induce graft-versus-host disease (GVHD). Skin rash appeared on the 18th day after the 2nd BMT, and biopsy from the rash on the 23rd day showed a typical picture of cutaneous GVHD (grade 2) and there was no evidence of viral infection. On the 36th day after the 2nd BMT, the patient died of veno-occlusive disease. Although graft-versus-leukemia effect in this patient could not be evaluated because of early death, the induction of GVHD with cyclosporine might be effective to reduce the relapse rate after syngeneic or autologous BMT. Further studies are required to confirm this effect.

Adult↗
PubMed1993

Surgical repair of type A aortic dissection by the circulatory arrest-graft inclusion technique in sixty-six patients.

During an 8-year period (1984 to 1991) 66 patients (mean age 59 years, range 26 to 84 years) with type A aortic dissection (60 ascending aorta tears, 6 arch tears; 35 acute, 31 chronic) had surgical repair by a continuous suture-graft inclusion technique. Hypothermic circulatory arrest (16 degrees C) was used in 58 patients (35/35 acute, 23/31 chronic; mean arrest time 26 minutes, range 10 to 55 minutes). Fifty-two patients had hemiarch repair and 6 had total arch replacement. Aortic valve disease necessitated treatment in 38 patients (1 valved conduit, 20 valve replacements, 17 valve repairs). Recently 11 patients had valve repair by reconstruction of the native aortic root, by means of techniques similar to those used for homograft valve insertion. Operative mortality was 9% (14% acute, 3% chronic). Stroke occurred in 2 patients (3%) and was fatal in both. Variables suggestive of increased operative risk by univariate analysis were acuteness (p = 0.12), visceral ischemia (p = 0.12), and preoperative shock (p = 0.13). No variable was significant by multivariate analysis. Overall actuarial survival at 48 months was 77%, with 3 late deaths from a ruptured distal aneurysm. Late computed tomography or magnetic resonance imaging scan was done in 28 patients at a mean interval of 33 months. These studies identified 1 patient with a pseudoaneurysm requiring reoperation and 3 patients with contained flow between the graft and the wrap. Three patients required late operation: 1 for pseudoaneurysm, 1 for arch dissection, and 1 for repair of a distal aneurysm.

Actuarial Analysis↗
PubMed1993

[Albumin and fibronectin dynamics in an experimental adult respiratory distress syndrome model].

We produced an experimental adult respiratory distress syndrome model by intravenous administration of oleic acid (OA) in 30 dogs (Group I: 10 normal dogs; Group II: 10 dogs with 0.02 ml/kg of OA; Group III: 10 dogs with 0.04 ml/kg of OA; Group IV: 10 dogs with 0.08 ml/kg of OA). Changes in albumin (AL) and fibronectin (FN) in serum and BALF of these dogs were examined. The following results were obtained: 1) Serum values of AL and FN were significantly decreased after OA injection as compared with the baseline values. These changes were not correlated with the severity of pulmonary edema. 2) BALF values of AL and FN were significantly increased after OA injection as compared with the baseline values. Significant linear correlations were found between the BALF value of AL and ELWV, and between BALF value of AL and delta ELWV, [r = -0.682, 0.573 (p < 0.01)]. Significant linear correlations were also found between the BALF value of FN and ELWV, and the BALF value of FN and delta ELWV, [r = 0.722, 0.650 (p < 0.01)]. BALF value of AL increased significantly even with the low OA dose (0.02 ml/kg). Thus in comparison with BALF value of AL after OA injection, BALF value of FN was significantly higher than that in the normal group even when pulmonary edema were severe (Groups III and IV). We concluded that we could estimate the severity of pulmonary edema by measuring BALF value of AL and FN simultaneously.

Animals↗
PubMed1992

Detection of human papillomavirus DNA in carcinomas of the nasal cavities and paranasal sinuses by polymerase chain reaction.

The authors retrospectively searched for human papillomavirus (HPV) types 16 and 18 in 60 cases of carcinoma arising from the nasal cavities (NC) and paranasal sinuses (PS) by using the polymerase chain reaction (PCR) on DNA extracted from formalin-fixed, paraffin-embedded tissues. In cases of SCC (n = 49), the authors also compared the clinical features of patients with HPV-positive and HPV-negative results to determine the clinical significance of HPV. HPV 16 and 18 were detected in 7 of the 49 cases (14%) of SCC. In the other histologic types of carcinoma (n = 11), neither HPV 16 nor HPV 18 was detected. No significant differences in the clinical features were observed between patients with SCC with HPV-positive and HPV-negative results. The results suggest that HPV 16 and 18 are implicated in the pathogenesis of SCC arising from the NC and PS. However, the presence of HPV is not related to local progression, occurrence of metastases, or the prognosis of the patients.

Adult↗
PubMed1992

Clinical significance of the epidermal growth factor receptor gene in squamous cell carcinomas of the nasal cavities and paranasal sinuses.

The authors retrospectively analyzed epidermal growth factor receptor (EGFR) gene amplification in 49 cases of squamous cell carcinoma (SCC) arising from the nasal cavities (NC) and paranasal sinuses (PS) by using slot-blot analysis of DNA extracted from formalin-fixed, paraffin-embedded tissues. Also, the relationship between the results of gene analysis and the clinical features of the patients was studied to investigate the clinical significance of the EGFR in SCC of the NC and PS. Amplification of the EGFR gene was detected in 5 of the 49 cases (10%). No significant difference was observed between EGFR gene amplification and the presence of lymph node metastases, local recurrence, or prognosis. This suggests that EGFR gene amplification is not related to the local progression or metastasis of the SCC in the NC and PS. In addition, it appears that amplification of the EGFR gene is not a prognostic indicator for SCC in the NC and PS.

Adult↗
PubMed1992

T cell receptor V beta repertoire of double-negative alpha/beta T cells in patients with systemic sclerosis.

OBJECTIVE: To analyze the T cell receptor V beta gene on double-negative (DN) alpha/beta T cells, which are increased in number, on peripheral blood lymphocytes (PBL) from patients with systemic sclerosis (SSc). METHODS: The DN alpha/beta T cells were sorted by flow cytometry from PBL obtained from 3 patients with SSc. The V beta repertoire was analyzed by polymerase chain reaction. RESULTS: Only 1 or 2 V beta genes (V beta 5/7, 5, or 17) were predominantly expressed on DN alpha/beta T cells from these 3 patients. CONCLUSION: The V beta repertoire on DN alpha/beta T cells in PBL from patients with SSc is rather restricted.

Base Sequence↗
PubMed1992

DNA damage-inducible origins of DNA replication in Escherichia coli.

Upon induction of the SOS response in Escherichia coli, the mode of initiation of DNA replication is altered such that it can occur in the absence of normally required protein synthesis. This type of DNA replication has been termed induced stable DNA replication (iSDR). We examined the origin usage during iSDR and found that the initiation of iSDR occurs primarily in the oriC and terC regions of the chromosome in a manner completely independent of transcription, translation and DnaA protein. Minichromosomes (oriC plasmids) pOC23 and pOC81 were induced to replicate in the absence of DnaA protein and transcription after SOS induction. The results localized one of the iSDR origin activities in a 596 bp region which includes the minimal oriC.

Bacterial Proteins↗
PubMed1992

Transcription in vivo within the replication origin of the Escherichia coli chromosome: a mechanism for activating initiation of replication.

Within the replication origin, oriC, of the Escherichia coli chromosome, novel in vivo transcripts were detected which proceeded rightward and whose production was activated by DnaA protein. In contrast, DnaA protein repressed the previously described ori-L leftward transcription. The former should introduce negative supercoiling, and the latter positive supercoiling, into the 13-mers. The effects of transcription on the initiation of replication were also investigated by making constructs with promoters placed near oriC. Transcription was found to enhance the origin activity only when it was oriented in such a way as to introduce negative supercoiling into the 13-mers. From these results, we propose that transcription within oriC regulates replication initiation by altering the topology of the 13-mer region.

Base Sequence↗
PubMed1992

Electrophysiological properties of neurones following mild and acute retinal ischaemia.

Early electrophysiological changes following acute retinal ischaemia were studied by recording single or multiunit retinal ganglion cells and the electroretinogram (ERG) in barbiturate anaesthetized cats. Retinal ischaemia was initiated photochemically by platelet aggregation in retinal vessels which had been irradiated with monochromatic green light following an intravenous injection of Rose Bengal dye. No physiologically active ganglion cells were found within, or close to, the irradiated sites with chorioretinal oedema. On the other hand, in the areas 5-20 degrees away from the irradiation sites, ganglion cells had abnormally raised spontaneous (background) firing which obscured visually driven firing. The retinal areas where no physiologically active ganglion cells were found showed histopathological changes which are similar to those described for glutamate-induced retinal damage. Retinal areas where depolarized retinal ganglion cells were located, however, showed only minor vacuolation of the ganglion cell fibre layer. Early global electrophysiological changes following photochemically induced retinal vascular lesion were consistent with those predicted from the findings in the single cell study. Vascular lesions produced with high irradiation energy (10-30 J), which promote extensive chorioretinal oedema, resulted in gradual loss of visually responsive ganglion cells. Lesions produced by low-energy irradiation (2 J), causing slight narrowing of the blood columns in the vessels, on the other hand, resulted in significant increases in the amplitude and the implicit time of the ERG b-wave and the background firing of multiunit retinal ganglion cells. Electrophysiological changes associated with mild retinal ischaemia are analogous to physiological effects associated with exogenous glutamate or blockade of glutamate uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1992

Studies on phosphoribosylpyrophosphate synthetase from Giardia intestinalis.

A substantial degree of purification, up to 3200-fold, with recoveries of 8-11% of phosphoribosylpyrophosphate (P-Rib-PP) synthetase from Giardia intestinalis extracts was achieved by the high resolution techniques of anion exchange chromatography and chromatofocusing columns on a fast protein liquid chromatography system. A Mono P chromatofocusing column gave rise to an enzyme peak eluting from the column at pH 4.5, indicating that the enzyme has an isoelectric point (pI) at approximately this value. The molecular weight of the enzyme was found to be 150,000 from a Sephacryl S-200 column. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the purified enzyme gave a single protein band with a subunit molecular weight of 38,000, indicating that the enzyme existed as a tetramer. The properties of G. intestinalis P-Rib-PP synthetase in terms of pH optimum, isoelectric point, subunit structure, phosphate requirement, metal and nucleotide specificity, appear to be very similar to those of the enzyme from other sources.

Animals↗
PubMed1992

Functional changes in thalamic relay neurons after focal cerebral infarct: a study of unit recordings from VPL neurons after MCA occlusion in rats.

We evaluated neuronal and histological changes of thalamic neurons 1, 4, 7, and 14 days after middle cerebral artery (MCA) occlusion in rats. After the somatosensory evoked potentials (SEPs) were measured from the cerebral cortex, the thalamic relay neuronal activities were recorded with a glass microelectrode following repetitive electrical stimulation of the contralateral forepaw at frequencies ranging from 1 to 50 Hz. In approximately 95% of the occluded rats, the ipsilateral somatosensory cortex and/or the subcortical somatosensory pathway developed infarct, resulting in SEP loss. We evaluated unit data from rats with abolished SEPs. The average firing rate of the nucleus ventralis posterolateralis (VPL) neurons in response to 25 stimulations at 30 Hz was significantly reduced to 0.1 spike/stimulus 1 day after MCA occlusion. In sham-operated rats, the same stimulation produced 0.7 spike/stimulus. The firing rate recovered to 0.4 spike/stimulus at 30-Hz stimulation 4 and 7 days after occlusion. This was followed by resuppression (0.1 spike/stimulus) 14 days after occlusion. Histological study revealed some abnormal neurons in the ipsilateral thalamus 7 days after occlusion. We were unable to find normal-shaped neurons in the VPL 14 days after occlusion. The present study demonstrates that cortical infarct produces functional and morphologic changes that gradually and progressively affect the ipsilateral thalamus, although incomplete transient recovery of somatosensory transmission may occur.

Animals↗