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Biomedical subjects

T Tsutsui

Publications and source records attributed to T Tsutsui.

At least 307 records · Page 17Linked to original sources
PubMed1986

[The effect of brain-stem vasomotor centers on the neurogenic control of cerebrovascular tonus--Part 3. The effects of destruction and stimulation of the brain-stem on intracranial pressure in acute subarachnoid hemorrhage].

The purpose of the present study is to clarify the effects of destruction and stimulation of the brain-stem on intracranial pressure (ICP) in experimentally induced subarachnoid hemorrhage (SAH). Using 23 cats, blood pressure (BP), ICP and local cerebral blood volume (CBV) were continuously measured. Acute SAH was produced by injection of autogenous blood (3 to 7 ml) into the cisterna magna. The animals were divided into two groups. Group A: those in which hypothalamic dorsomedial nucleus (DM) and reticular formation of the midbrain (MBRF) were coagulated bilaterally one hour after SAH and Group B: in addition to the procedure of Group A, reticular formation of the medulla oblongata (MORF) was electrically stimulated bilaterally. In 19 out of 23 cats of both groups, transient small increases in ICP and CBV were observed during coagulation and/or stimulation of DM, MBRF and MORF respectively in the animals whose ICP remained approximately 20 mmHg or below and progressive increase in ICP was never evoked. In 3 animals of Group A whose ICPs remained high at more than 20 mmHg, sequential destruction of DM and MBRF induced stepwise increase in ICP to 40 to 80 mmHg and consequently resulted in acute brain swelling. In 1 animal of Group B whose ICP fluctuated around 20 to 40 mmHg, biphasic increase in ICP to 100 mmHg was repeatedly evoked by stimulation of MORF. It is concluded that in the condition of increased ICP produced by SAH, lesions in the DM and MBRF and stimulating condition of MBRF may result in acute brain swelling.

Acute Disease↗
PubMed1985

Ultrasonic aspiration in coronary artery surgery.

With the aid of an ultrasonically powered aspiration device, the coronary artery to undergo distal anastomosis during aortocoronary bypass grafting can be exposed in the beating heart prior to institution of cardiopulmonary bypass and systemic administration of heparin. The thick adipose tissue and bridging muscles of the superficial layer are removed with almost no bleeding, leaving the vascular elements intact. The optimal site for anastomosis of the coronary artery is readily exposed and confirmed, and aortic cross-clamp time is minimized.

Coronary Vessels↗
PubMed1985

Local cerebral glucose utilization during nitrous oxide and pentobarbital anesthesia in rats.

Local cerebral glucose utilization was measured in rats during nitrous oxide and pentobarbital anesthesia, using the 2-[14C]-deoxyglucose method. During nitrous oxide anesthesia, 67%, marked heterogeneity of glucose utilization was observed. During pentobarbital anesthesia (30 mg/kg), glucose utilization decreased, the decrease being pronounced in the structures where glucose utilization was high during nitrous oxide anesthesia. During combined use of nitrous oxide and pentobarbital (30 mg/kg), with an electroencephalogram (EEG) consisting of 4-6 Hz wave super-imposed by 10-15 Hz wave, glucose utilization was higher in many brain structures, including the midbrain reticular formation, than that observed during pentobarbital (30 mg/kg) anesthesia alone. With pentobarbital, 125 mg/kg, the EEG became nearly flat and a dose-related decrease in glucose utilization was observed in the cerebral cortices and inferior colliculus but not observed in any other structures. During the combined use of nitrous oxide and pentobarbital (125 mg/kg), the EEG was nearly flat, and no statistically significant differences in glucose utilization were observed as compared with those during pentobarbital (125 mg/kg) anesthesia in any of the structures examined. The results suggest that nitrous oxide and pentobarbital affect local cerebral glucose metabolism differently and that nitrous oxide acts as cerebral metabolic stimulant in the presence of cortical function during pentobarbital anesthesia.

Animals↗
PubMed1985

Acute but intermittent sticking of a Björk-Shiley mitral valve in closed position.

An acute, intermittent sticking of a Björk-Shiley valve placed in the mitral position is described. It occurred shortly after the valve replacement, but 9 hours later, this 10-year-old female patient recovered from the accident without reoperation. Fluid infusion, left atrial compression, a sharp precordial blow or atrioventricular sequential pacing were effective for unlocking or prevention of the stuck valve. The mechanism was suspected to be impingement of remnant chordae tendinea.

Blood Pressure↗
PubMed1984

Patterns of relapse of squamous cell carcinoma of the maxillary sinus.

Ninety-five M0 patients with squamous cell carcinoma of the maxillary sinus were treated mainly with combined surgery, radiation and chemotherapy. They were staged surgically according to the American Joint Committee TNM classification: 3 were T2N0, 55 T3N0, 27 T4N0 and 10 T3-4N1-3 patients. Relapse developed in 66 patients (69%): one (33%), 35 (64%), 22 (81%) and 8 (80%), respectively. All patients experienced relapse within 2 years after diagnosis. Local recurrence developed during the course of disease in 52 (79%) of the 66 patients who relapsed. Three patients with cervical relapse and one with local recurrence were successfully salvaged with rescue surgery. Local control achieved in 39 (41%) of the 95 patients: 2 (67%), 28 (51%), 7 (26%) and 3 (30%) in T2N0, T3N0, T4N0 and T3-4N1-3 patients, respectively. Autopsy findings of 17 patients are presented. An impact of computed tomography on staging of maxillary sinus tumors is discussed.

Adult↗
PubMed1984

Dependence of lethality induced by a direct DNA perturbation of synchronized human diploid fibroblasts on different periods of the DNA synthetic period (S phase).

The cytotoxic effect of a direct perturbation of DNA during various portions of the DNA synthetic period (S phase) of cultured human diploid fibroblasts was examined. The cells were synchronized by a period of growth in low serum with a subsequent blockage of the cells at the G1/S boundary by hydroxyurea. This method resulted in over 90% synchrony, although approximately 20% of the cells were noncycling. Synchronized cells were treated for each of four 2-hour periods during the S phase with 5-bromodeoxyuridine (0.1-10 microM), followed by irradiation with near-UV (5-10 min). The 5-bromodeoxyuridine-plus-irradiation treatment was cytotoxic, while treatment with 5-bromodeoxyuridine alone or irradiation alone was not cytotoxic. The cytotoxicity was dependent upon the periods of S phase during which treatment was administered. The highest lethality was observed for treatment in early to middle S phase, particularly in the first 2 hours of S phase, whereas scarce lethality was observed in late S phase. The extent of substitution of 5-bromodeoxyuridine for thymidine in newly synthesized DNA was similar in every period of the S phase. Furthermore, no specific period during S phase was significantly more sensitive to treatment with respect to DNA damage, as determined by an induction of unscheduled DNA synthesis. These results suggest that a certain region or regions in the DNA of human diploid fibroblasts, as designated by their specific temporal relationship in the S phase, may be more sensitive to the DNA perturbation by 5-bromodeoxyuridine treatment plus near-UV irradiation for cell survival.

Bromodeoxyuridine↗
PubMed1984

Characterization of an unscheduled DNA synthesis assay with Syrian hamster embryo cells.

The Syrian hamster embryo cell transformation assay is widely used for studies of carcinogenesis. The characterization of an unscheduled DNA synthesis (UDS) assay for these cells is reported. Benzo[a]pyrene, aflatoxin B1 and UV light induced UDS in the cells in a dose-dependent manner without exogenous metabolic activity. Nitrosopiperidine induced UDS as well as gene mutations and cell transformation only in the presence of an exogenous metabolic activation system. The utility of this UDS assay with these cells is discussed.

Aflatoxins↗
PubMed1984

Induction of unscheduled DNA synthesis in cultured human oral keratinocytes by sodium fluoride.

The effect of treatment of cultured human oral keratinocytes with sodium fluoride (NaF) has been investigated with respect to induction of unscheduled DNA synthesis (UDS). Oral keratinocytes were isolated from excised buccal mucosa of normal individuals by trypsinization at 4 degrees C overnight, followed by separation of the epithelium of mucosa from lamina propria mucosae with forceps. Isolated cells were cultured in vitro and all experiments were performed with secondary cultures. For detection of UDS, the keratinocytes were cultivated with medium containing 1% fetal calf serum (FCS) for 2 days and then treated with 100-300 micrograms/ml NaF for 4 h in medium containing 1% FCS and 10 mM hydroxyurea (1% FCS-HU medium). Following treatment with NaF, UDS was measured by direct scintillation counting of [3H]thymidine incorporated into DNA of the cells in 1% FCS-HU medium. Significant levels of UDS were induced in a dose-related fashion by NaF treatment. The results suggest that NaF causes DNA damage in cultured human oral keratinocytes.

Cells, Cultured↗
PubMed1984

Amitrole-induced cell transformation and gene mutations in Syrian hamster embryo cells in culture.

Amitrole, a widely used herbicide, is an animal carcinogen and an inducer of cell transformation. However, it is inactive as a mutagen in bacterial test systems. Thus, it has been suggested that amitrole is a non-mutagenic carcinogen. Over the dose range that induces morphological transformation of Syrian hamster embryo cells in culture, amitrole induced gene mutations at the Na+/K+ ATPase and hypoxanthine phosphoribosyl transferase loci measured concomitantly in the same cells. These results indicate that amitrole may act via a mutational mechanism.

Amitrole↗
PubMed1984

Cytotoxicity, chromosome aberrations and unscheduled DNA synthesis in cultured human diploid fibroblasts induced by sodium fluoride.

The effects of exposure of cultured human diploid fibroblasts (JHU-1 cells) to sodium fluoride have been studied with respect to cytotoxicity and induction of chromosome aberrations and unscheduled DNA synthesis (UDS) Cytotoxicity of NaF on JHU-1 cells, as determined by a decrease in colony-forming ability, linearly increased with increasing dose of NaF (50-150 micrograms/ml) or exposure time (1-24 h). Treatment of the cells with 50 micrograms/ml NaF for 24 h resulted in a lethality (approximately 70%) similar to that obtained with 100 micrograms/ml for 12 h. A linear increase in cytotoxicity was observed as a fraction of the product of NaF treatment time and dose. JHU-1 cells treated with 20-50 micrograms/ml NaF for 12 or 24 h were analyzed for chromosome aberrations. A significant increase in the frequency of chromosome aberrations at the chromatid level was observed in treated cells in a dose-dependent manner. For detection of UDS, confluent JHU-1 cells were cultured with medium containing low serum and then exposed to NaF in the presence of 10 mM hydroxyurea. Treatment with 100-400 micrograms NaF/ml for 4-24 h reproducibly elicited UDS in a dose-related fashion as determined by direct scintillation counting of [3H]thymidine incorporated into DNA during repair synthesis. These results suggest that NaF causes DNA damage in human diploid fibroblasts in culture.

Cell Survival↗
PubMed1984

Colcemid-induced neoplastic transformation and aneuploidy in Syrian hamster embryo cells.

Treatment of Syrian hamster embryo cells in culture with 0.01-0.1 micrograms/ml of colcemid for 48 h resulted in morphological and neoplastic transformation of the cells. Cell transformation was observed with doses which were non-cytotoxic and did not cause mitotic inhibition of the cells. Higher dose of colcemid (greater than 0.1 microgram/ml) resulted in mitotic inhibition of the cells and a significant loss of colony forming ability, but no increase in the frequency of morphological transformation. Treatment of the cells with transforming doses of colcemid did not result in any measurable induction of gene mutations or structural chromosome aberrations; however, numerical chromosome changes in the treated cells were observed. A 14-fold increase in the number of aneuploid cells with a near diploid chromosome complement was found in cultures treated with 0.1 micrograms/ml colcemid and both chromosome loss and gain were induced. The dose response curves for colcemid induced morphological transformation and aneuploidy were similar. These results are consistent with a role of carcinogen-induced chromosome non-disjunction in carcinogenesis.

Aneuploidy↗