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T Maeno

Publications and source records attributed to T Maeno.

122 records · Page 7Linked to original sources
PubMed1966

Analysis of sodium and potassium conductances in the procaine end-plate potential.

1. The effect of procaine on neuromuscular transmission was studied on the sartorius muscle of the frog, Rana pipiens, with intracellular microelectrodes.2. Mean quantal content of the e.p.p. in high Mg Ringer was little affected by procaine.3. The short circuit effect of the e.p.p. on the action potential, which was an indication of change in potassium conductance (Deltag(K)) during the e.p.p., was investigated on the muscle fibre immobilized in hypertonic Ringer. It was found that procaine had little effect on Deltag(K).4. The equilibrium potential of the e.p.p. (E(e.p.p.)) was measured in hypertonic Ringer. E(e.p.p.) was 12 mV in control experiment and was decreased to 3.1 mV in 10(-4) procaine. The ratio Deltag(Na)/Deltag(K) was calculated to be 2.75 in control and 2.11 in 10(-4) procaine.5. E.p.p.s were recorded extracellularly to study changes in the time course of Deltag(Na) in procaine. Procaine reduced the peak magnitude of Deltag(Na); following the peak, Deltag(Na) fell quickly to a lower level, which decayed much more slowly.6. An end-plate model with separate sodium and potassium pathways is proposed to explain the procaine e.p.p. Procaine is assumed to affect the time course of Deltag(Na).7. E.p.p.s simulated from the proposed end-plate model with theoretical Deltag(Na) and Deltag(K) agreed satisfactorily with actual procaine e.p.p.

Animals↗
PubMedDate not supplied

Survival of allografted pancreatic islets in the subretinal space in rats.

The purpose of this study was to determine whether the subretinal space would provide immune privilege for pancreatic islet transplantation. Islets from outbred Sprague Dawley (SD) rats were isolated by collagenase digestion, and about 200 handpicked islets were transplanted into the subretinal space of SD rats. Similar grafts were transplanted into the subconjunctival space of SD rats as controls. Transplanted eyes were enucleated after 2 to 60 days, fixed and embedded in paraffin for immunoperoxidase staining of insulin, glucagon, and CD8+ lymphocytes. Clinical examination of rat eyes revealed minimal or no inflammation in the anterior chamber or vitreous at any time point. Fifteen of 19 subretinal allografts survived up to 60 days. Few CD8+ lymphocytes were present in the subretinal grafts and the endocrine cells stained intensely for insulin and glucagon at all time points. In contrast, CD8+ lymphocytes were present in subconjunctival grafts in rats by day 14 and all grafts were destroyed by day 21. These results suggest that the subretinal space provides immune privilege for islet allotransplantation by preventing massive lymphocyte infiltration.

Animals↗
PubMedDate not supplied

Expression cloning and signal transduction pathway of P2U receptor in mammary tumor cells.

Extracellularly applied ATP, UTP and UDP induce a transient increase in the intracellular Ca2+ concentration of mammary cells via a P2U receptor. The P2U receptor in the mammary tumor cell line MMT060562 was cloned and expressed in the human leukemia cell line K-562. The deduced amino acid sequence of the mammary tumor cell P2U receptor was 98% homologous with that of mouse NG108-15 cells. It was a member of the superfamily of GTP-binding-protein-coupled receptors. ATP and UTP induced the increase in the intracellular concentrations of Ca2+ and inositol-1,4,5-trisphosphate in both mammary tumor cells and P2U-receptor-expressed K562 cells. Dose-response curves on the production of inositol-1,4,5-trisphosphate and Ca2+ by ATP and UTP were consistently similar. Injection of GTP enhanced the ATP-induced outward current and injection of GTP gamma S induced a repetitive outward current. Both pertussis and cholera toxins did not affect ATP-induced calcium increase. It was suggested that the P2U receptor coupled with pertussis- and cholera-toxin-insensitive GTP-binding proteins and activated phosphoinositide turnover.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Does earlier detection of lung cancer on mass screening improve outcome in younger and middle-age patients?

In order to demonstrate clinicopathological features, especially in relation to the detection of lung cancer in younger (<40 years) and middle-aged patients, a total of 850 patients with lung cancer were analyzed with reference to their basis for detection. Asymptomatic patients in their forties and fifties diagnosed on mass screening had higher prevalence rate of surgically resectable disease and better three-year survival compared with patients who required medical attention because of symptoms. Our results suggest that mass screening for patients under the age of 50 years does not change the outcome, however, patients in the age group 50-59 years receive some benefit in our screening system.

Adenocarcinoma↗
PubMedDate not supplied

Patterns of pancreatic metastasis from lung cancer.

BACKGROUND: Metastatic involvement of the pancrease is not an uncommon autopsy finding, however, pancreatic metastasis is an infrequent clinical condition and the pattern of the metastases have not been studied. We conducted a retrospective study in order to evaluate the pattern of the metastasis from lung cancer. PATIENTS: From 1976 to 1997, 26 patients with pancreatic metastasis were identified by searching the medical records of 850 patients with lung cancer. RESULTS: The usual pattern of pancreatic metastasis involved a solitary nodule in 19 patients (73.1%); multiple nodules in 3(11.5%), and diffuse swelling in 4(15.4%). Nineteen(73.1%) and 18(69.2%) of 26 patients had liver and adrenal gland metastases, respectively. CONCLUSIONS: Pancreatic metastasis represents a common site of extrathoracic spread of disease for the small number of patients with advanced lung cancer, especially in small cell lung cancer. The usual pattern of the metastasis is a solitary nodule. In order to diagnose exactly, abdominal CT scan would be helpful in such metastasis.

Adult↗