Search PubMed⌕ Search

Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 1,009 records · Page 56Linked to original sources
PubMed1986

Chemical modification of calcium release from the sarcoplasmic reticulum of mechanically skinned skeletal bullfrog muscle fibers.

Several types of reagents that react with amino acid side chains induced repetitive phasic contracture of skinned skeletal muscle from frogs. The presence of 10 mM procaine or 5 mM magnesium in the medium or disruption of the sarcoplasmic reticulum (SR) eliminated this contracture, indicating that the calcium-induced calcium-release mechanism of SR is involved in the contraction. Dithiothreitol inhibited the contracture induced by chloramine T, N-acetylimidazole, or p-chloromercuriphenylsulfonic acid (pCMPS) but not in the case of carbodiimide, phenylglyoxal, trinitrobenzenesulfonic acid, diethylpyrocarbonate (DEP), or N-chlorosuccinimide (NCS). Therefore, modification of groups other than the sulfhydryl ones seems to induce contractures under such conditions. The amplitude of the caffeine-induced contracture decreased after treatment with pCMPS, DEP, or NCS. NCS shifted the pCa-tension curve toward low pCa in the SR-disrupted fibers. This shift would explain the decrease in the caffeine contracture. It is tentatively concluded that pCMPS and DEP release a large amount of calcium from SR.

Animals↗
PubMed1986

Morphological aspects of the surfactant system in human lungs. A freeze-fracture study.

We examined alveolar type II cells and extracellular surfactant (tubular myelin) of human lungs and compared them with those of experimental animals (mouse, rat and dog) using a freeze-fracture technique for electron microscopy. Lamellar bodies (intracellular surfactant) in alveolar type II cells of human lung showed features different from those of the experimental animal lungs. Namely, multicentric foci of lamellae, an amorphous portion with some degree of lattice-like structure in the mature bodies, unpaired split membranes of lamellae and also our previously reported connection of the lamellar bodies to the endoplasmic reticulum (Am. Rev. resp. Dis. 127: 1983) were found in alveolar type II cells of human lungs but not in type II cells of experimental animal lungs. On the other hand, there were no differences noted in extracellular surfactant between human and experimental animal lungs. These findings indicate the possibility that a mode of surfactant production and/or storage in alveolar type II cells exists in human lung which is different from that in experimental animal lungs.

Aged↗
PubMed1986

[Pulsed Doppler echocardiographic evaluation of hemodynamics in premature ventricular contractions].

To investigate hemodynamic changes in ventricular premature contractions (VPCs), the blood flow velocities at the left ventricular (LV) outflow and inflow tracts were analyzed by pulsed Doppler echocardiography in 23 patients with VPCs and in two patients with ventricular parasystoles. Percent LV stroke volume of the ectopic and the postectopic sinus beats to the other sinus beats and %LV inflow volume of the sinus beats preceding ectopic beats to the other sinus beats were calculated from the time integral of the blood flow velocity. The following results were obtained. The %LV stroke volume of VPCs or %LV inflow volume of the preceding sinus beats correlated positively with the coupling interval of VPCs (r = 0.69, p less than 0.001 and r = 0.67, p less than 0.001, respectively). The %LV stroke volume of VPCs correlated positively with %LV inflow volume of the preceding sinus beats (r = 0.84, p less than 0.001). In some patients with VPCs of the RBBB pattern and in one patient with VPCs of the LBBB pattern associated with abnormal right axis deviation, the %LV stroke volume of VPC was much more reduced. In patients with depressed rapid filling and increased atrial filling, %LV stroke volume of the VPC or %LV inflow volume of the preceding sinus beat was smaller than in the other patients with the same coupling interval of VPCs. In VPCs of right ventricular (RV) origin, deterioration of RV hemodynamics was more prominent than in those of LV origin, and vice versa. Increased LV stroke volume was observed in postextrasystolic sinus beats, related to the coupling intervals of VPCs. However, the sum of %LV stroke volume of VPC and the postextrasystolic sinus beat decreased as the coupling intervals of VPC shortened. These results suggest that not only the coupling interval and the origin of VPCs but the LV diastolic behavior, as well, are important factors determining the hemodynamics in VPCs. They also suggest that the increment of stroke volume in postextrasystolic beats is more prominent in VPCs with shorter coupling intervals, but the LV performance as a whole is more depressed in VPCs with a shorter coupling intervals. In conclusion, pulsed Doppler echocardiography proved a useful noninvasive technique for evaluating the hemodynamics of VPCs.

Cardiac Complexes, Premature↗
PubMed1986

[AIDS--a further development].

It has been recently established that AIDS is a virus infectious disease. HTLV-I essentially makes T4 lymphocytes malignant and induces their abnormal proliferation. However, on the way, when HTLV-I induces a decrease in the function of T4 lymphocytes, the symptoms of ARC or AIDS take place on occasion. HTLV-III/LAV possesses a central function to destroy T4 lymphocytes, but, when this function is blocked, it increases T4 lymphocyte proliferation. Accordingly, the concept of carriers of the AIDS virus and patients with AIDS-related complex or AIDS has been clarified. Simultaneously, it has been discovered that a multiplicity of amino acids exists on the envelope of isolated AIDS viruses, resulting in a variety of viral envelope antigenicities. This may support the presence of antigenic modulation, which might make the development of a vaccine more difficult. Therapy has been approached from the following points of view; blockers of reverse transcriptase, drugs for destroying the virus itself through the viral envelope, vaccination, replacement of patient's T4 lymphocytes with healthy bone marrow, and use of immunopotentiators.

Acquired Immunodeficiency Syndrome↗
PubMed1986

[The features of liver metastasis of breast cancer on imaging and its response to arterial infusion chemotherapy].

Arterial infusion chemotherapy was performed in 21 patients with liver metastasis of breast cancer, which was suspected to be the limiting factor of the prognosis, and the relationship between the morphological types of liver metastases, percentage of the liver involved, their angiographic features and chemotherapeutic response was discussed. Four morphological types of liver metastases could be classified; solitary mass type, multiple nodular type, diffuse small nodular type, and mixed type. In most cases, metastatic lesions were detected as a hypoechoic area on US and as a low-density area on pre-enhanced CT scan. In their angiographic features, these lesions were revealed as hypervascular tumors in most cases. Enlargement of the common or proper hepatic artery and obstruction of the 1st or 2nd branch of the portal vein were seen in over 50% of cases. In 13 evaluable cases, the response rate was 84.6% (PR 11, NC 1, PD 1), and the 50% survival time was 13.5 months in responders and 11.0 months for all cases. With regard to the morphological type, 1, 2 and 4-type cases revealed partial response, but NC or PD cases belonged to morphological type 3. No relation between obstruction of the portal vein and the chemotherapeutic response was observed. Arterial infusion chemotherapy was thus shown to be an effective treatment for liver metastasis of breast cancer, but that the response to the treatment differed for each morphological type.

Adult↗
PubMed1986

[Two cases of testicular torsion diagnosed by the ultrasonic Doppler method].

Two cases of testicular torsion diagnosed with ultrasonic Doppler method are reported. Case 1. A 17-year-old male noticed pain and swelling of the right intrascrotal contents during sleeping and visited our clinic. A Doppler signal was obtained from the normal testicle, but not from the affected one. Bilateral orchiopexy was therefore done under the diagnosis of right testicular torsion. Case 2. A 20-year-old male visited our clinic with complaints of pain and swelling of the right intrascrotal contents. The ultrasonic Doppler method revealed no blood flow to the right testicle. After manual detorsion, pain improved and Doppler sound was audible. Bilateral prophylactic orchiopexy was performed later.

Adolescent↗