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Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 487 records · Page 27Linked to original sources
PubMed1987

Possible regulation mechanism of potent nucleoside triphosphate hydrolase in Toxoplasma gondii.

A dormant enzyme, nucleoside triphosphate hydrolase (EC 3.6.1.3) purified from the tachyzoite of Toxoplasma gondii, was activated by the treatment with dithiothreitol. The catalytic activity remained after exclusion of dithiothreitol from the enzyme solution with a Sephadex G-25 column. This activity was completely blocked by the additional treatment with N-ethylmaleimide. It was concluded that the activation occurred through the reductive cleavage of disulfide bond on the enzyme. The reduced type of thioredoxin, partially purified from mouse liver, could replace the effect of dithiothreitol. These results strongly suggest that the enzyme activity is regulated by the oxido-reduction change in the enzyme molecule.

Adenosine Triphosphate↗
PubMed1987

Detection of nucleoside triphosphate hydrolase as a circulating antigen in sera of mice infected with Toxoplasma gondii.

The nucleoside triphosphate hydrolase, which is present in the tachyzoite form of Toxoplasma gondii, was detected as a circulating antigen in sera of mice infected with a virulent (RH) or an avirulent (Beverly) strain of T. gondii. The enzyme was detected with a monoclonal antibody incorporated into an enzyme-linked immunosorbent assay. The lower limit of sensitivity of the assay was about 0.3 ng/ml, and standard assays provided a linear plot of nucleoside triphosphate hydrolase concentration over a range of 0.3 to 12 ng/ml. In mice inoculated intraperitoneally with tachyzoites of the RH strain, nucleoside triphosphate hydrolase emerged in the serum 1 day after injection, and then the concentration increased and reached a value of 30 micrograms/ml on day 5. In mice inoculated intraperitoneally with cysts of the Beverly strain, nucleoside triphosphate hydrolase was detected at day 3 after injection, and a peak concentration of 89 ng/ml was seen on day 10. The concentration of enzyme decreased thereafter, and the enzyme disappeared from the circulation on day 56.

Animals↗
PubMed1987

A case of amputation neuroma presenting proptosis.

A case of amputation neuroma, presenting incidious proptosis, was reported in a 44-year-old man. To the best of our knowledge the case seems to be the first report of amputation neuroma caused by trauma in the orbita.

Adult↗
PubMed1987

Study on congenital complete heart block in children by 24-hour ambulatory electrocardiographic monitoring.

Ambulatory electrocardiographic monitoring was performed in 18 children with a congenital complete heart block (CCHB). They had no cardiac structural anomalies. These patients could be divided into 3 groups according to the pattern of fluctuations in beat-to-beat ventricular rates. Type 1 patients showed rapid and transient fluctuations and demonstrated a high correlation between atrial and ventricular rates. Type 3 patients showed a constant ventricular rate and little variation through the 24 hour period and there was no appreciable correlation between atrial and ventricular rates. Twelve of 18 patients had additional arrhythmias. A few sporadic ventricular premature contractions (VPCs) were found in 9 patients, and bigeminy of VPCs or ventricular tachycardias were seen in 2 patients during exercise. Frequent and sudden prolongation of RR intervals was found during sleep in 3 patients. The longest intervals of ventricular asystoles were 7.2, 3.2 and 3.2 sec, respectively. The mechanism of this phenomenon appeared to be not only an exit block, but also arrest or a lack of automaticity of a subsidiary pacemaker. One of these patients developed frequent Stokes-Adams attacks. Type 3 patients with sudden prolongation of RR intervals and/or frequent ventricular arrhythmias should be under careful observation. Ambulatory electrocardiographic monitoring is recommended for children with CCHB for evaluation of potential risk factors for Stokes-Adams attacks.

Adolescent↗
PubMed1987

Splenic rupture in acute megakaryoblastic leukemia.

A 43-year-old man with pancytopenia and circulating blast cells was found to have acute megakaryoblastic leukemia. Bone marrow biopsy disclosed reticulin fibrosis with infiltration of blast cells. Cytogenic study showed 48,XY,+15,+18. The megakaryocytic origin of blast cells was confirmed by platelet peroxidase reaction at ultrastructural level. The spleen which had not been felt on admission increased in size rapidly and ruptured abruptly. This appears to be the first reported case of a splenic rupture associated with acute megakaryoblastic leukemia.

Acute Disease↗
PubMed1987

[A personal point of view to EC-IC bypass surgery in completed stroke after the co-operative study].

The role of EC-IC bypass surgery has become a very controversial issue recently. EC-IC anastomosis was performed in 132 patients of stroke in our institute. Thirty six of them which could be followed up completely had a completed stroke and ten of these showed a significant clinical improvement by the next day of surgery. We studied the angiograms, CT scans and dynamic CT studies of all 36 patients to determine the common factors responsible for a significant clinical improvement in these ten patients. It was found that patients with occlusion of middle cerebral arteries and with good collateral circulation fared better than those with other lesions and good cross circulation. Site of low density on CT revealed patient with watershed low density did well. Characteristic of low density area was found to be a significant factors. If the low density area was homogeneous and well defined in an arterial territory, it was invariably associated with no improvement after surgery. Patients showing an improvement had scattered or irregular low density areas. Dynamic CT studies were not found to be significant.

Brain↗
PubMed1987

[Total femur replacement in osteogenic sarcoma of the femur].

A 14-year-old girl was admitted with a diagnosis of osteogenic sarcoma of the distal femur. Pre-operative chemotherapy was effective, and sclerosis of the lesion made clear the presence of a proximal femoral and pulmonary metastasis. Total femur and knee joint replacement with titanium alloy was made after a total resection of the femur. Her post-operative clinical course was excellent without local recurrence. Now, 14 months after the operation, she can walk without crutches. We wish to emphasize that the presence of a pulmonary metastasis is not absolutely a contraindication as long as the tumor appears surgically resectable and responsive to per-operative chemotherapy.

Adolescent↗