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Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 361 records · Page 20Linked to original sources
PubMed1994

[Decreased theophylline clearance in children with acute asthma with concurrent febrile respiratory infection].

Elevated serum levels of theophylline, a first-line anti-asthma drug, are sometimes associated with febrile respiratory infection (FRI). Although it seems to be wellknown, conflicting reports still appear in journals. We studied retrospectively theophylline clearance (th-cl) in 74 episodes of acute asthma (44 with and 30 without FRI, in patients aged 12-mos.-13-yrs.) and tried to reveal the effect of fever or pathogens on th-cl. Th-cl was estimated by a single sample technique during intravenous drip infusion of aminophylline. The results were as follows: 1) Forty four episodes with FRI included 20 viral, 10 bacterial and 2 Mycoplasma pneumoniae infections (Table 2). 2) Th-cl in 44 episodes with FRI was significantly lower than in 30 without FRI (p < 0.001). 3) Decreased tendency of th-cl in episodes with viral infection was observed, but statistically it was not significant (p < 0.1). However, the differences of th-cl among 9 pair-cases with and without viral infection were quite clear (p < 0.01). 4) Th-cl in episodes with 10 bacterial and 2 Mycoplasma infections was reduced significantly (p < 0.01). 5) There was no difference in th-cl between episodes with viral, and bacterial or Mycoplasma infections (p < 0.1). As a result, it is suggested that fever, regardless of its origin, may decrease th-cl in acute asthma with FRI.

Acute Disease↗
PubMed1993

Localization of trkB mRNA in postnatal brain development.

We investigated the localization of trkB mRNA, which encodes a putative component of high-affinity brain-derived neurotrophic factor (BDNF) or the neurotrophin-3 (NT-3) receptor, in the postnatal rat brain by in situ hybridization histochemistry. At birth, trkB mRNA was strongly expressed in various regions with the thalamus and cerebral cortex showing the strongest expression. As the rat grows, expression generally persisted or declined in most regions with the exception of the hippocampus where trkB mRNA expression increased during postnatal development. In the adult brain, trkB mRNA was detected in the olfactory system, cerebral cortex, hippocampal formation, amygdala, and cerebellar cortex. These findings, together with the developmental profiles of BDNF and NT-3 mRNA expressions, suggest that trkB product (gp145trkB) mainly transduces NT-3 signals early in the postnatal period, and BDNF signals later in the period.

Aging↗
PubMed1993

Homologous recombination-dependent initiation of DNA replication from DNA damage-inducible origins in Escherichia coli.

Escherichia coli cells induced for the SOS response express inducible stable DNA replication (iSDR) as an SOS function. Initiation of iSDR is independent of transcription, translation and DnaA protein, which are essential for initiation of DNA replication from oriC. We found that a recA mutant that is defective in recombination but proficient in SOS induction could not elicit iSDR. In contrast, iSDR was enhanced by recD and recJ mutations that inactivate the exonuclease V activity of the RecBCD enzyme and the RecJ exonuclease activity, respectively. A mutation in the ruvC gene that blocks the resolution of recombination intermediates (i.e. Holliday structures) also enhanced iSDR. Furthermore, inhibition of branch migration by recG or ruvAB mutations dramatically increased the iSDR activity. recBC mutants are defective in iSDR induction but the defect was suppressed by a mutation in the sbcA gene. The major product of minichromosomes replicated by iSDR was covalently closed circular monomers. We propose that recombination intermediates (i.e. D-loop structures) created by the action of RecA recombinase and RecBC(D) helicase play a central role in initiation of iSDR.

Bacterial Proteins↗
PubMed1993

Increased levels of tumor necrosis factor and interleukin 1 in bronchoalveolar lavage fluids from pigs infected with Mycoplasma hyopneumoniae.

We examined the levels of tumor necrosis factor (TNF)-alpha and interleukin-1 (IL-1) in bronchoalveolar lavage fluids (BALF) from pigs experimentally infected with Mycoplasma hyopneumoniae using biological assays with WEHI-164 cells and D10.G4.1 cells, respectively. Increased TNF-alpha and IL-1 in BALF were found in infected pigs with gross and/or microscopic lesions. A time-course study suggested TNF-alpha and IL-1 to be persistently elevated in infected pigs. Their presence in BALF would thus appear to be associated with the development of pneumonic lesions in M. hyopneumoniae infected pigs.

Animals↗
PubMed1993

Differential expression of two members of FGF receptor gene family, FGFR-1 and FGFR-2 mRNA, in the adult rat central nervous system.

The fibroblast growth factor (FGF) receptor gene family now contains four members that encode homologous receptor-tyrosine kinases (RTKs) to each other. We have demonstrated that one of the members, FGFR-1 (also termed as flg), is expressed in the widespread but specific neuronal populations in the adult rat central nervous system (CNS). In the present study, we examined the expression pattern of another member, FGFR-2 (also termed as bek) and compared it with that of FGFR-1. In contrast with FGFR-1, we detected FGFR-2 expression primarily in the fiber tracts of the adult rat CNS, suggesting that the oligodendrocytes are the main sites of the FGFR-2 expression. These findings indicate that FGF may regulate neurons and glial cells through different subtypes of its cognate receptor.

Animals↗
PubMed1993

Requirement of homologous recombination functions for viability of the Escherichia coli cell that lacks RNase HI and exonuclease V activities.

rnhA224 and rnhA339::cat mutants which lack RNase HI activity were found to constitutively express the sfiA::lacZ operon fusion in a recA+ lexA(+)-dependent manner. The sfiA::lacZ expression (indicating SOS induction) in rnhA mutants was increased to higher levels by the introduction of the recD1903 or recB21 mutation. The SOS induction in these cells was further enhanced by nutritional shift up from casamino acid medium to Luria broth. Although the extent by which the recD and recB mutations increased the sfiA expression in rnhA mutants was similar, the rnhA224 recB21 double mutant had plating efficiencies that were 25-fold lower on casamino acid plates and 5 x 10(5)-fold lower on Luria broth plates than the respective plating efficiencies of either rnhA224 recD or rnhA::cat recD double mutants. Whereas the recD mutation inactivates the exonuclease activity of the RecBCD (Exo V) enzyme without reducing the recombination proficiency of the mutant, the recB21 mutation abolishes both the exonuclease activity and recombination capability. Therefore, in the absence of both RNase HI and Exo V activities, homologous recombination functions become crucial for viability, particularly in Luria broth. Introduction of mutations in recA, recJ and recN exacerbated the phenotypes. It is proposed that R-loops which persist due to the lack of RNase HI activity can be removed by two alternative routes of DNA repair: one involving Exo V, Exo I and DNA polymerase I, and the other involving both the RecBCD and RecF pathways of homologous recombination activities. The isolation of RNA polymerase mutants that constitutively express the SOS response at high levels and exhibit remarkable broth-sensitivity lend strong support to the contention that increased amounts of the persisting R-loop in rnhA mutants growing in Luria broth give rise to a stronger SOS response.

DNA Helicases↗
PubMed1993

The distance between the grille of the laryngeal mask airway and the vocal cords. Is conventional intubation through the laryngeal mask safe?

The distance between the grille of the laryngeal mask airway and the vocal cords was measured with a fibreoptic bronchoscope in 30 male and 30 female patients. The mean distance was 3.6 cm (SD 0.5 cm; range 2.5-4.7 cm) in males and 3.1 cm (SD 0.5 cm; range 2.0-4.2 cm) in females. These results suggest that the cuff of an uncut 6.0 mm tracheal tube would often lie between the vocal cords when the tube is fully inserted through a laryngeal mask airway. To avoid this complication, the tracheal tube must protrude more than 9.5 cm beyond the grille of the laryngeal mask airway. When either neck extension or flexion is required, the laryngeal mask airway should be removed as the margin of safety is small.

Adult↗
PubMed1993

[Effect of erythromycin on neutrophil adhesion molecules].

The mechanisms of erythromycin (EM) in chronic lower respiratory tract diseases including diffuse panbronchiolitis (DPB) has been reported. In this study we investigated the effect of EM on peripheral neutrophil adhesion molecules such as LFA-1 and Mac-1 obtained from six healthy subjects. Pretreatment of neutrophils with each concentration (10 ng/ml approximately 100 micrograms/ml) of EM resulted in no significant reduction in the expression of LFA-1 alpha, beta and Mac-1. Moreover, EM had no capability of reducing these expressions even when neutrophils were pretreated with 1 microgram/ml of EM at time from 0 to 60 min. These findings indicate that EM does not directly reduce the expression of LFA-1 alpha, beta and Mac-1 on peripheral neutrophil obtained from healthy subjects.

Adult↗
PubMed1993

Chemiluminescence of neutrophils in patients with myeloproliferative or myelodysplastic hematologic diseases--relation to neutrophil alkaline phosphatase activity.

In hematological diseases such as myeloproliferative disorders (MPD) or myelodysplastic syndromes (MDS), some abnormalities in the chemiluminescence of neutrophils are observed. There are two groups; one includes chronic myelogenous leukemia (CML), essential thrombocythemia (ET) and MDS, which all have decreased chemiluminescence of neutrophils. The other group includes polycythemia vera (PV) which has increased neutrophil chemiluminescence. We studied the neutrophil function by analyzing the chemiluminescence in 35 patients with hematological diseases. In most of these cases the defects in chemiluminescence in 35 patients with hematological diseases. In most of these cases the defects in chemiluminescence in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) were correlated with those in response to phorbol 12-myristate 13-acetate (PMA). But there were exceptional cases in which the maximal light emission of chemiluminescence (Max CL) in response to FMLP was obviously lower than controls despite the fact that the Max CL in response to PMA was the same as the controls. These facts suggest a heterogenicity of the defect site in these diseases. There was a correlation between the level of chemiluminescence and the neutrophil alkaline phosphatase (NAP) activity in these patients. In vitro culture of CML neutrophils with granulocyte colony-stimulating factor (G-CSF) showed a correlation between the increase in the level of chemiluminescence and NAP activity. These results suggest that NAP may take part in the control of neutrophil function.

Alkaline Phosphatase↗
PubMed1993

Unusual meningeal tuberculoma--case report.

A 60-year-old male presented with bilateral papilledema. Neuroimaging showed a densely enhanced flat tumor within the interhemispheric region in the frontal and parietal lobes with sulcal obliteration and enhancement. There was no history of tuberculous infection. Histological examination of the excised tissue from the flat tumor within the interhemispheric region was consistent with tuberculoma. Multiple antituberculous agent therapy resolved the papilledema and reduced the tumor.

Diagnosis, Differential↗
PubMed1993

The treatment of intracapsular hip fractures with total hip arthroplasty in rheumatoid arthritis.

Total hip arthroplasty was performed on 41 patients with rheumatoid arthritis for 43 intracapsular hip fractures from 1971 to 1989. Followup, observation of clinical signs, and radiographs were conducted between one to ten years. Of the 41 patients, 25 had died by the end of the study. Total hip arthroplasty was found to be effective in relieving joint pain, and the walking ability of patients generally recovered to pre-injury status following the operation. Some patients experienced deterioration of the knee and ankle joints due to rheumatoid arthritis, and in such cases there was progressive loss of walking ability. Nevertheless, the function of the hip joint was well preserved, and most patients reported that pain had disappeared and the joint range of motion had returned to normal. In only one case was revision surgery necessary. There was little overall loosening of prostheses, and there were no problems concerning the durability of the artificial joint. The presence, therefore, of femoral neck fractures in patients with rheumatoid arthritis, who are to be encouraged to get out of bed and begin walking as soon as possible, is a strong indication for total hip arthroplasty.

Aged↗
PubMed1993

New approaches in the treatment of hypertensive intracerebral hemorrhage.

A comparison of the long-term outcome after surgical and nonsurgical treatment of hypertensive putaminal hemorrhage was performed in Japan over the last 15 years to determine the appropriate role of surgery. The overall results show a poor response to surgical treatment, but neurosurgeons also know that hematoma evacuation may bring about a dramatic result in some cases. In addition, experimental studies have shown that hematoma evacuation improves neuronal function at the penumbra. The discrepancy between the results of this study and the neurosurgeon's clinical impression is probably a reflection of the following. In the past, the decision to operate was determined mainly by the location of the hemorrhage as determined by computed tomography and/or magnetic resonance imaging. However, this method of deciding surgical indications is probably not correct. We are trying to change the method of determining the surgical indications from morphological to physiological criteria as follows: All patients are initially treated with hyperbaric oxygen, and those who show improvement of their symptoms are clearly indicated for surgery. If the somatosensory evoked potential or auditory brain stem response shows an improvement after administration of mannitol or glycerol, this is also an indication that surgery should be performed.

Animals↗