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Biomedical subjects

K Tamura

Publications and source records attributed to K Tamura.

At least 937 records · Page 52Linked to original sources
PubMed1991

Pharmacological studies with the alpha 2-adrenoceptor antagonist midaglizole. Part I: Respiratory and cardiovascular systems.

Respiratory and cardiovascular effects of midaglizole (DG-5128, CAS 66529-17-7) were investigated in comparison with yohimbine, idazoxan and tolbutamide. 1. Respiration: Midaglizole had little or no effect on respiration of anesthetized dogs. Yohimbine and idazoxan augmented respiration at low dose. Tolbutamide depressed respiratory rate and depth at high dose. 2. Blood pressure and heart rate: Midaglizole produced dose-related hypotension and bradycardia in anesthetized dogs which had laparotomy, whereas it had little or no effect on blood pressure and heart rate of dogs which had no laparotomy (unlaparotomized dogs). Tendency of slight hypertension was observed after high dose of tolbutamide in laparotomized dogs, and transient hypotension was induced in unlaparotomized dogs. Yohimbine and idazoxan increased blood pressure at low dose in unlaparotomized dogs. In laparotomized dogs, yohimbine produced hypertension and hypotension at low and high doses, respectively. In isolated guinea pig atria, midaglizole produced bradycardia which was not observed after yohimbine. Tolbutamide decreased the pulse rate at high concentration. 3. Cardiac contractility: Midaglizole produced increase in cardiac contractility of anesthetized dogs. Yohimbine and idazoxan, at low dose, showed similar inotropic activity. Prazosin also produced a positive inotropic effect, whereas tolbutamide lacked the activity. The inotropic effects of midaglizole and yohimbine were antagonized by pretreatment with propranolol or hexamethonium, whereas a similar effect of prazosin was not influenced by both blockers. In isolated guinea pig atria, midaglizole showed slight inotropic activity. Yohimbine was without any effect, whereas tolbutamide reduced the contractile force. 4. Femoral blood flow: Midaglizole produced a transient increase in femoral blood flow and a decrease in femoral arterial resistance of anesthetized dogs. Yohimbine and idazoxan, at low dose, showed similar vasodilator activity. Prazosin also produced a vasodilator effect, whereas tolbutamide lacked the activity. The vasodilator effects of midaglizole and yohimbine were not affected with propranolol, but inhibited after hexamethonium. 5. Mesenteric blood flow: Midaglizole significantly decreased mesenteric blood flow and increased the arterial resistance of anesthetized dogs in a dose dependent manner. Tolbutamide induced a decrease in blood flow and an increase in arterial resistance only at the highest dose used. Yohimbine increased mesenteric blood flow at low dose and decreased it at high dose. 6. Renal blood flow: Midaglizole dose-relatedly decreased renal blood flow of anesthetized dogs. Tolbutamide and yohimbine at high dose produced a long-lasting decrease of the blood flow. Midaglizole produced a slight transient reduction of renal arterial resistance which was followed by a slight increase. Tolbutamide increased the arterial resistance at high dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1991

Identity determinants of E. coli tRNAs.

Identity determinants of E. coli tRNA(Val) and three class II tRNAs, tRNA(Ser), tRNA(Tyr) and tRNA(Leu), are studied by using various variants of tRNA transcripts. Anticodon, discriminator base and acceptor stem are involved in the identity elements for tRNA(Val). Discrimination among class II tRNAs are considered to be dependent on the bases at positions 2, 71 and 73 as well as their different tertiary structures including the long variable arm.

Codon↗
PubMed1991

[Exercise induced precordial T wave normalization associated with U wave inversion in detection of left anterior descending artery stenosis].

Although normalization of inverted T wave is not an uncommon finding during exercise tests, it's clinical significance is still unclear. Exercise 12-lead electrocardiograms (ECGs) were recorded by using Master's 2-step or ergometer. T wave normalization in the anterior chest leads was found in 20 patients with, and 14 patients without coronary artery disease (CAD). Coronary angiography and/or exercise Tl-201 myocardial imaging were also performed in every patient. Exercise-induced T wave normalization was defined as "inverted T wave at rest becoming upright during exercise". ST segment, T and U wave amplitudes were measured before and immediately after exercise. 1) All of the 20 patients (100%) with CAD demonstrated critical stenosis of the left anterior descending artery (LAD). 2) ST deviation was noted in none of the 14 patients (0%) without CAD, and in only 4 of the 20 patients (20%) with CAD. 3) T wave amplitude increased equally in patients both with and without CAD. 4) Exercise-induced U wave inversion was found in 16 of the 20 patients (80%) with CAD, whereas it was found in only 1 of the 14 patients (7%) without CAD. 5) The sensitivity of "U wave inversion" in detection of LAD stenosis was 80%, and the specificity was 93%. We conclude that exercise-induced T wave normalization associated with U wave inversion in anterior chest leads is highly indicative of the specific presence of critical LAD stenosis.

Adult↗
PubMed1991

[The influence of left atrial cuff rejection on pulmonary hemodynamics after canine lung allotransplantation].

Several factors influence pulmonary hemodynamics after lung transplantation: reimplantation response, lung rejection reaction and imperfect anastomosis technique. In this experiment, five cases presented marked elevation of mean pulmonary artery pressure at the time or right pulmonary artery occlusion test performed two weeks postoperatively. Left atrial cuff rejection reaction arose in one case in which edema and stenosis of the pulmonary vein outflow tract were evidenced. This finding demonstrated that the changes in pulmonary hemodynamics after transplant suggest the possibility of inducement by left atrial cuff rejection reaction.

Animals↗
PubMed1991

[The role of surgeon in treatment of chronic respiratory failure after pulmonary tuberculosis operations].

We analyzed pulmonary functions and rib cage-phrenic motions on 296 cases of chronic empyema patients who had surgical treatment. Pulmonary functions were better preserved in patients with a single step than in those with multi-step operations, and in those who had more than five operations the impairment was inevitable. Both %VC and rib cage-phrenic motions improved by decortication, and by air-plombage, but in those who developed multi-rib fractures after the latter procedure, ipsilateral chest wall motion almost disappeared. Since some restriction of rib cage-phrenic motion is inevitable after the surgery, we have developed a cuirass respirator which can synchronize with the respiration to assist the movement of the chest wall. The results attained so far are satisfactory.

Aged↗
PubMed1991

[Pulmonary inhalation scintigraphy using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) aerosol].

N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) is lipophilic substance and permeates through the alveolar epithelium via intracellular transport, whereas 99mTc-DTPA is water-soluble substance and permeates through the alveolar epithelium via paracellular transport. We performed inhalation lung imaging using 123I-IMP and 99mTc-DTPA in order to assess alveolar epithelial permeability in 4 patients with restrictive ventilatory impairment, and 5 volunteers including one smoker. The time-activity (T/A) curves of 123I-IMP were well fitted into two compartments, first and slow, by least-squares fit technique, in contrast to 99mTc-DTPA fitted well with one compartment. In 4 normal volunteers, the T/A curves of the lower pulmonary fields declined faster than those of other pulmonary fields. In 99mTc-DTPA studies, the Kep values of patients with restrictive ventilatory impairment (n = 4) were higher than those of normal volunteers (n = 4) (2.14 +/- 0.30 x 10(-4) vs 1.48 +/- 0.41 x 10(-4), p less than 0.005). On the other hand, in 123I-IMP studies, the Kep values of the patients were much lower than those of normal volunteers (6.79 +/- 0.55 x 10(-5) vs 1.52 +/- 0.45 x 10(-3), p less than 0.005).

Administration, Inhalation↗
PubMed1991

[A case of tuberculous osteomyelitis resembling metastatic cancer on bone scintigraphy].

A 48-year-old male was referred to our division, on the suspicion of lung cancer with bone metastasis. Chest radiography showed a mass shadow and bone scintigram demonstrated multiple scattered regions of increased uptake. However bronchial and bone biopsy specimens revealed granuloma with epithelial cells and giant cells. A diagnosis of tuberculous osteomyelitis was made, and antituberculous therapy was begun. Chest radiography and bone scintigrams one year later showed marked improvement.

Antitubercular Agents↗
PubMed1991

[Clinical observations and the planning of therapy for sacrococcygeal tumors].

Amongst sacrococcygeal tumors, teratoma is seen often while other histologic types are rare. It is apparent that the less obvious intrapelvic tumors can cause obstructive symptoms and are usually diagnosed late. Twenty cases of sacrococcygeal tumor, including 14 teratomas (9 benign, 5 malignant) and 6 others (3 benign, 3 malignant) were treated at Tokyo Medical College and Shizuoka Children's Hospital over the last 23 years. The majority of the benign tumors were readily excised, but one case of benign teratoma was difficult to excise and died of bleeding. The resectability of malignant tumors was low, but aggressive multiagent chemotherapy, radiotherapy and second look operation made it possible to increase the survival. One case is alive and has been disease free for 11 years. Recently combined therapy by chemotherapy and surgery has improved the survival rate although some problems still remain.

Child, Preschool↗
PubMed1991

[In vitro chemosensitivity test with several antitumor agents against eight malignant brain tumor cell-lines].

We performed an in vitro chemosensitivity test with 8 malignant brain tumor cell lines, which were established in our Department. It was shown that ACNU was moderately tumoricidal against only one cell (ONS-86) line. IFN-beta (interferon-beta) was more active against 4 cell (ONS-6, -20, -76, and -81) lines. VCR (vincristine), MTX (methotrexate), and Ara-C (cytosine arabinoside) and FK 973 were most effective against all 8 cell lines. There were some difference in the drug sensitivities among the tumors with the same pathological diagnosis. Since IFN-beta was tumoricidal against to the cells, co-culture of IFN-beta and one of other antitumor agents seemed to induce more antitumor effects. With regard to the side effects of IFN-beta, the combined therapy with IFN-beta and other drugs induced more antitumor effects against malignant brain tumor cells and seemed to reduce the side effects.

Antineoplastic Agents↗
PubMed1991

[Bloodless open heart surgery using membrane oxygenator--the efficacy of ultrafiltration].

The efficacy of ultrafiltration (UF) in the attempt of total bloodless open heart surgery using membrane oxygenator (MO) was investigated in two groups. Group I (GI) consisted of 6 ASD operations between Dec. 1983 and Feb. 1987, which cardiopulmonary bypass (CPB) were performed without UF and with non-hemic priming of Capiox II MO. (Age; 18 +/- 2 (SD) years old, Body Weight; 53 +/- 6 kg, CPB; 77 +/- 24 min.) Group II (GII) consisted of 11 cases (4ASD, 1VSD, 4MS/MR (2MVR), 2AR (2AVR] between Mar. 1987 and Sep. 1988, which CPB were performed with UF in 9 cases and with non-hemic priming of CML/VPCML MO. (Age; 34 +/- 20 yo, Body Weight; 52 +/- 12 kg, CPB; 112 +/- 54 min). Total bloodless surgery were successful in 9 cases (82%) of GII against in only one case (17%) of GI (p less than 0.05). The hematocrit values of successful 9 cases in GII were 40 +/- 2% before operations, more than 19 +/- 3% during CPB, 33 +/- 4% just after operations, and more than 29 +/- 3% through the postoperative course. Blood loss during operations were 1013 +/- 586 ml in GI, and 659 +/- 388 ml in GII (NS). Blood loss after operations were 696 +/- 283 ml in GI and 478 +/- 284 ml in GII (NS). In successful 9 cases of GII, blood loss after operations were 387 +/- 215 ml, significantly less than that in GI (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Antitumor activity of FK973 for malignant gliomas and its assessment for normal brain cells].

FK973, a novel antitumor antibiotic, was obtained as a fermentation product of Streptomyces sandaensis. FK973 had excellent cytotoxic effects against in vitro cultured human glioblastomas, medulloblastomas, and murine glioma (203 glioma) cells. The antitumor effects were also well observed against ACNU resistant glioma cells. FK973 did not go through the blood-brain barrier. The median survival time (MST) of MG models treated with FK973 was 21 days. On the other hand, the MST of the control group was 15 days. In the in vitro assessment against neural disturbance, FK973 showed a little disturbance of murine brain cells but less toxic than ADM. In the in vivo neurotoxicity examination, FK973 showed no clear damage to the neural cells and myelin sheaths.

Animals↗
PubMed1990

A phase I study of a new cisplatin derivative for hematologic malignancies.

DWA2114R (DWA) is a new derivative of platin compounds that is currently being used in Phase II studies of solid tumors in Japan. The dose-limiting factor is myelotoxicity with mild extramedullary toxicity. This Phase I study consisted of adult patients with relapsed hematologic malignancies. Eight patients received a total of 15 treatment courses of DWA. The starting dose was 800 mg/m2 over 24 hours by continuous infusion. The dose was first increased to 1200 mg/m2 and then to 1600 mg/m2. Clinical toxicity and urinary excretion studies of DWA suggested that 1200 mg/m2/d for successive days would be the best type of administration. When 1200 mg/m2/d was given for 5 days, Grade 2 to 3 diarrhea and nausea and vomiting were encountered requiring parenteral fluids and nutritional support. This suggested that the dose-limiting factor with this schedule was gastrointestinal toxicity. Myelotoxicity was severe, as expected, but tolerable. One of the five patients with acute nonlymphocytic leukemia (ANLL) entered into complete remission and one patient with chronic myelogenous leukemia (CML) in crisis returned to the chronic phase. A Phase II trial of DWA is warranted for hematologic malignancies, especially in myeloid diseases.

Adult↗
PubMed1990

Ethanol induces interdigitated gel phase (L beta I) between lamellar gel phase (L beta') and ripple phase (P beta') in phosphatidylcholine membranes: a scanning density meter study.

Effects of ethanol on dipalmitoylphosphatidylcholine (DPPC) and distearoylphosphatidylcholine (DSPC) dispersions were investigated with an automated scanning density meter and a differential scanning calorimeter (DSC). The temperature-dependent profile of specific volume measured by the density meter clearly exhibited phase transitions of the DPPC and the DSPC dispersions as drastic changes in the thermal expansion coefficients. On increasing the ethanol concentration in the DPPC dispersions, the pretransition temperature was reduced faster than the main transition temperature was. An interdigitated gel phase (L beta I) appeared as a region of lower specific volume at the pretransition temperature when the ethanol concentration reached 40 mg/ml. The L beta I phase spread both its ends in an ethanol-dependent fashion, and the high-temperature end merged to the main transition at 50 mg/ml of ethanol. The temperature-ethanol phase diagram has been determined for DPPC. The transitions L beta' to L beta I and from L beta I to P beta' were also observed on the thermograms of DSC measurements. In the DSPC dispersions, the L beta I phase was induced between the L beta' and the P beta' phases by a lower ethanol concentration (about 20 mg/ml).

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

[CT and US findings of gauzeoma].

We described the CT and US findings of gauzeoma in 7 patients, in which the masses were histologically proved. In the wide range of the CT findings, whirl-like spongiform pattern and the wavy striped high density area were characteristic of gauzeomas. The typical US features of gauzeomas were a cystic mass with the distinct internal echoes and strong acoustic shadows. The internal echo were occasionally curve-linear in shape. Gauzeomas are not common disease. However, when the findings described above are seen in the patients who have previously had an abdominal surgery, gauzeomas should be suspected.

Abdomen↗