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Biomedical subjects

T Kamada

Publications and source records attributed to T Kamada.

At least 883 records · Page 49Linked to original sources
PubMedDate not supplied

MRI of mucosal malignant melanoma of the head and neck.

PURPOSE: The objective of this study was to determine the characteristic MR findings for mucosal malignant melanomas of the head and neck. METHOD: We retrospectively analyzed the MR images for six patients with this entity. T1-weighted SE images with and without gadolinium and T2-weighted fast SE images were obtained. MR images were analyzed qualitatively and quantitatively by comparing the signal intensity of the melanoma with that of muscle. RESULTS: On T1-weighted images, five melanomas were hyperintense and one was isointense. On T2-weighted images, five were of mixed intensity and one showed isointensity. The mean signal intensity ratio of the primary melanoma to muscle was 1.51 and 1.39 on T1-weighted images with and without gadolinium, respectively. These values were not statistically significant. CONCLUSION: Hyperintensity on T1-weighted images is characteristic of this entity, but not universal.

Adipose Tissue↗
PubMedDate not supplied

Power spectral analysis of heart rate variability in Type As and Type Bs during mental workload.

Recently several studies have suggested that there are differences in autonomic balance between Type As and Type Bs. This study evaluates a sympathovagal interaction in Type A (n = 8) and Type B (n = 11) male students during a mental arithmetic task by power spectral analysis of heart rate variability. The low-frequency component to high-frequency component ratio was significantly greater in Type As than in Type Bs during a resting period. No significant differences were found in heart rate changes and blood pressure between the two kinds of subject groups. The present findings indicate that there was a significant difference in sympathovagal balance between Type As and Bs. Type As showed dominant sympathetic activity.

Adult↗
PubMedDate not supplied

Effects of loxoprofen sodium, a newly synthesized non-steroidal anti-inflammatory drug, and indomethacin on gastric mucosal haemodynamics in the human.

Non-steroidal anti-inflammatory drugs (NSAID) are, and have been, frequently used for alleviation of pain in patients; however, they are known to cause gastric mucosal injury in experimental animals and in humans. A decrease in the gastric mucosal blood flow also plays an important role in the aetiology of acute gastric mucosal injury, as we previously reported. This study investigated the effect of a newly synthesized NSAID, loxoprofen sodium (sodium 2[p-2 oxocyclopentylmethyl) phenyl]propionate dihydrate, on gastric mucosal haemodynamics using a reflectance spectrophotometry system. Both single and cross-over methods were used in five volunteer subjects. Loxoprofen sodium 60 mg (one tablet) or indomethacin 25 mg (one tablet), was diluted in 10 mL water at 25 degrees C and sprayed on the gastric mucosa via a polyethylene tube inserted into the biopsy channel of an endoscope. After drug administration, reflectance spectra were taken every 5 min for 30 min. The indices of mucosal haemoglobin content (IHb) and oxygen saturation of haemoglobin (ISO2) were determined by the method previously reported by the authors. Indomethacin administration produced a significant decrease in both IHb and ISO2 values, indication ischaemia. Loxoprofen sodium, however, showed no significant differences in either of the parameters. Haemorrhagic erosions were evident after indomethacin administration, but none were found after loxoprofen sodium administration. The conclusion reached on the basis of this evidence is that one-time topical application of loxoprofen sodium is safer than indomethacin.

Administration, Oral↗
PubMedDate not supplied

Epithelial-myoepithelial carcinoma of the nasopharynx.

We present a patient with a rare epithelial-myoepithelial carcinoma of the nasopharynx with a typical biphasic histopathologic pattern. Immunohistochemical findings support the concept that the inner cells differentiate to ductal epithelium and the outer cells to myoepithelium. In this patient complete excision of the tumor and reconstruction with a pedicled sternocleidomastoid myocutaneous flap were performed. A DNA diploid pattern from flow cytometric study indicates a favorable prognosis. There was no recurrence nor metastasis for 55 months.

Aged↗
PubMedDate not supplied

A new approach to antithrombotic therapy--evaluation of combined therapy of thromboxane synthetase inhibitor and very low dose of aspirin.

The effect of a selective thromboxane (TX) synthetase inhibitor (OKY-046), alone and in combination with a very low dose of aspirin, on the platelet function was studied in healthy and diseased subjects. A single dose of 100 mg OKY-046 was orally administered to patients with ischemic cerebrovascular disease (CVD) and healthy volunteers. TXB2 generation and platelet aggregation were measured before and at 1, 4, 6 and 8hr after dosing. In addition, after the administration of a very low dose of aspirin (0.1-0.25 mg/kg/day) for at least one month, a single dose of OKY-046 was given to CVD patients. TXB2 generation and platelet aggregation were measured in the same manner as OKY-046 alone. The effect of OKY-046 on platelet aggregation induced by arachidonic acid (AA) was different in each subject whereas platelet TXB2 generation was almost completely inhibited in all of the patients and healthy volunteers. OKY-046 had a slight inhibitory effect on collagen induced aggregation. A combination of OKY-046 with a very low dose of aspirin, on the other hand, produced additional inhibition of the platelet aggregation induced by both AA and collagen. The present results suggest that the accumulation and metabolism of cyclooxygenase products that accumulate when TX synthetase is blocked, differ in each subject, additional inhibition is caused by the combined use of TX synthetase inhibitor and a very low dose of aspirin because the very low dose of aspirin partially reduces the proaggregatory cyclooxygenase products that accumulate when TX synthetase is blocked.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylates↗
PubMedDate not supplied

The effect of the calcium antagonist nimodipine on the gerbil model of experimental cerebral ischemia.

The gerbil model was used to assess the therapeutic effects of the calcium antagonist nimodipine on cerebral ischemia. Transient cerebral ischemia was produced in each gerbil by bilateral common carotid occlusion of 10-, 15- or 20-min duration. Nimodipine (0.01 or 0.1 mg/kg) was administered intraperitoneally just before the carotid occlusion or 10-30 min after the removal of the arterial clips. Morbidity of each animal was evaluated using the stroke index, and the sum of stroke indices was calculated for evaluating the overall morbidity during a particular period of reperfusion. Mortality was observed for 24 hours after clip removal. Although, depending on the timing of the drug administration, the low-dose (0.01 mg/kg) nimodipine worsened the morbidity in the gerbils with 10-min ischemia, the high-dose (0.1 mg/kg) of the drug had a clear beneficial effect on the mortality associated with cerebral ischemia. These results are considered worthwhile for further trials to assess the usefulness of nimodipine as a therapeutic agent in the management of the acute ischemic stroke.

Animals↗
PubMedDate not supplied

Effect of aspirin and ticlopidine on platelet deposition in carotid atherosclerosis: assessment by indium-111 platelet scintigraphy.

The antiplatelet effects of aspirin and ticlopidine were studied by a dual-tracer method, using indium-111 labeled platelets and technetium-99m human serum albumin, in a group of 12 patients with suspected ischemic cerebrovascular disease. The magnitude of platelet accumulation at the carotid bifurcation was expressed as the ratio of radioactivity of indium-111 platelets deposited on the vascular wall to those circulating in the blood-pool (PAI, platelet accumulation index), 48 hr after injection of labeled platelets. PAI values were measured before (baseline studies) and after the antithrombotic therapies (aspirin studies: 325 mg bid for 22.3 +/- 1.3 days, ticlopidine studies: 100 mg tid for 21.8 +/- 2.1 days). At the baseline, the mean PAI value at 24 carotid bifurcations in the patient group was 15.7 +/- 15.3% (mean +/- S.D.) compared to -4.3 +/- 9.1 at 24 carotid bifurcations in 12 normal subjects (p less than 0.01). We defined the upper limit for a normal PAI (%) value to be +13.9, namely the mean PAI plus 2 SD for the carotid bifurcation in normal subjects and used this value for semiquantitative analysis. At the baseline, significant elevation of PAI (more than 13.9%; positive scintigram) was observed at 12 of 24 vessels, while 12 other regions were negative (less than 13.9%). In the lesions with positive scintigraphic results at the baseline, the mean PAI (%) value from the baseline, aspirin and ticlopidine studies was 29.5 +/- 7.0, 11.2 +/- 8.5 (p less than 0.01 versus baseline) and 21.4 +/- 21.3 (not significant from baseline), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Manifestations of temporary symptoms during endoscopic variceal sclerotherapy using thrombin as a sclerosant.

We performed 93 sclerotherapy sessions on liver cirrhosis patients with recurrent variceal bleedings. In each session, hypertonic glucose, thrombin and 1% polidocanol were consecutively injected into the varices, and changes in the hemostatic system were examined in relation to the symptoms observed during the treatment. Patients underwent sclerotherapy with no complaints in 62 (67%) sessions, and complained of slight symptoms of general fatigue and headache in 19 (20%). In the other 12 (13%) sessions, the procedure was discontinued due to marked manifestations of these symptoms. All symptoms were temporary and disappeared completely after the procedure. These temporary symptoms were closely related to changes in coagulation tests similar to those of disseminated intravascular coagulation, which were observed just after the treatment. Possible activation of the renal kallikrein-kinin system following injection sclerotherapy was also demonstrated.

Endoscopy↗
PubMedDate not supplied

Fasting plus prandial insulin supplements improve insulin secretory ability in NIDDM subjects.

To examine how insulin secretory ability is modified by strict glycemic control in non-insulin-dependent diabetes mellitus (NIDDM) subjects, basal and/or prandial insulin was supplemented for 4 wk in 24 diabetic subjects who were secondary failures to sulfonylurea treatment. One intermediate-acting insulin injection a day (n = 7) failed to suppress the rise in plasma C-peptide after meals and did not improve plasma C-peptide responses during a posttreatment oral glucose challenge. Continuous subcutaneous insulin infusion with a premeal bolus (n = 8) suppressed both fasting and meal-related rises in C-peptide and improved C-peptide response during the posttreatment oral glucose challenge. Daily insulin requirements during the 4 wk of treatment were reduced significantly by 52%. A short-acting insulin injection before each meal (n = 9) without basal supplementation suppressed the prandial rise in C-peptide and was associated with a significant reduction in daily insulin requirements during 4 wk of treatment by 28%. Diabetic subjects whose fasting and prandial hyperglycemia were less than 140 and less than 200 mg/dl, respectively, showed a significantly higher C-peptide response during oral glucose challenge after treatment than those whose insulin treatment only normalized (less than 200 mg/dl) prandial but not basal hyperglycemia (greater than 140 mg/dl). These results suggest that a short-term period of meal-related insulin treatment (which normalized prandial glycemia) increases residual beta-cell function in NIDDM subjects who failed long-term sulfonylurea administration. A basal insulin supplement alone was not effective. The effectiveness of a prandial insulin supplement may have been further improved by a combined basal and meal-related treatment program.

Acetohexamide↗
PubMedDate not supplied

Superoxide dismutase enhances both adenosine release and coronary hyperemic flow through protection of 5'-nucleotidase against its degradation during reperfusion following ischemia in dogs.

Oxygen-derived free radicals are thought to inactivate ectosolic enzymes that regulate myocardial cellular functions. One such enzyme is ecto-5'-nucleotidase, which is responsible for adenosine production during coronary hyperemic flow. In the present study, we measured both reactive and hyperemic flow and adenosine release during reperfusion with and without superoxide dismutase. In 10 open chest dogs, the left anterior descending coronary artery was perfused through an extracorporeal bypass tube from the carotid artery. In the control hearts, a five-minute occlusion of the coronary artery caused the hyperemic flow with increased release of adenosine. In the superoxide dismutase-treated hearts, although administration of superoxide dismutase altered neither adenosine release nor coronary blood flow in the baseline, it augmented both peak coronary blood flow and repayment, and adenosine release during reperfusion. Therefore, we hypothesized that superoxide dismutase reduces generation of oxygen-derived free radicals during ischemia and reperfusion and attenuates the degradation of ecto-5'-nucleotidase. The administration of superoxide dismutase enhanced the increase in ecto-5'-nucleotidase activity at 10 minutes after reperfusion over the untreated group. Thus, we conclude that superoxide dismutase enhances reactive hyperemic flow and adenosine release during reperfusion following ischemia, which may be attributable to the protection of ecto-5'-nucleotidase by superoxide dismutase during ischemia and reperfusion.

5'-Nucleotidase↗
PubMedDate not supplied

Reduction in the incidence of Helicobacter pylori-associated carcinoma in Japanese young adults.

Helicobacter pylori (Hp) is a major risk factor for gastric carcinogenesis. In Japan, the incidence of Hp infection in young adults has declined markedly. The purpose of this study was to clarify this trend in the incidence of Hp-associated gastric carcinoma (GCa) in young (under 30 years of age) Japanese patients. We enrolled 53 such patients who underwent surgical resection of GCa in one of 18 hospitals in the Hiroshima prefecture between 1976 and 1999. The patients were classified into groups based on three 8-year periods (1976-83, 1984-91, and 1992-1999) in which their cases occurred. We compared the numbers of patients and estimated the histology of carcinomas, grades of gastritis and Hp infection histologically. Of the 53 patients, 49 (92%) showed Hp infection. The frequency of GCa in young adults has decreased gradually (21, 18, and 14 patients in 1976-83, 1984-91 and 1992-99, respectively). The numbers of Hp-positive carcinomas decreased radically (21, 17 and 11 patients, respectively). This trend was associated with improvement in the degree of gastritis in non-neoplastic mucosa. Of the four Hp-negative patients, three had signet ring cell carcinoma. Moreover, the numbers of patients with non-signet ring cell carcinoma also decreased (18, 12 and 7 patients in each period, respectively). These results suggest that Hp-associated carcinoma has declined gradually in young Japanese.

Adolescent↗
PubMedDate not supplied

The phase I/II clinical study of carbon ion therapy for cancer of the uterine cervix.

PURPOSE: The phase I/II clinical study of carbon beam therapy was undertaken for 31 cases of advanced cervical cancer of stages IIIB and IVA from June 1995 to November 1997. The main purpose was to determine clinically useful fraction doses without severe acute reaction of normal tissues and to assess tumor control dose levels achievable without significant normal tissue toxicity. PATIENTS AND METHODS: The treatment was given with four fixed fractions per week (24 fractions over 6 weeks) and was initiated with a fraction dose of 2.2 Gray equivalent (GyE), and the dose was increased as 2.4 GyE, 2.6 GyE, 2.8 GyE, and 3.0 GyE. Consequently, the total dose initiated was 52.8 GyE, to increase up to 72.0 GyE in 4.8-GyE increments in the dose-escalation fashion. Thirty patients with eligible advanced cervical cancers consisting of 27 squamous cell carcinomas and three adenocarcinomas were analyzed. RESULTS: Acute response of normal tissues was less than with photon treatment until fraction doses of 2.8 GyE were administered, and patients finished treatment with comfortable conditions. Severe late complications occurred in the two patients who received more than 67.2 GyE. The 2-year cumulative survival rate and the local control rate of 27 patients with squamous cell carcinoma were 61.5% and 59.3%, respectively. According to stages, the 2-year survival rates of stage IIIB and IVA patients were 54.4% and 75.0%, respectively. The 2-year local control rates of stage IIIB and IVA patients were 52.6% and 75.0%, respectively. DISCUSSION: These results indicated that the disease control seems to be relatively better for very advanced disease and with dose escalation treatment. Local control was not significantly correlated with total dose and tumor volume. The results of the present study, despite small numbers and short observation, suggest that an adequate fraction dose for pelvis fields is 2.8 to 3.0 GyE and that the carbon beam therapy might be advantageous for advanced cervical cancer.

Adult↗
PubMedDate not supplied

Results of prophylactic adjuvant chemotherapy for early stage non-Hodgkin's lymphoma of the head and neck.

Results were reviewed in 46 patients who had stage I and II head and neck non-Hodgkin's lymphoma, and received five to six cycles of CVP chemotherapy after regional irradiation. Disease-free survival, pattern of relapse, and time of relapse were compared with those of 64 patients, who received regional irradiation alone. Adjuvant, post irradiation CVP significantly improved five-year survival in stage I (and IE) disease, 49.6% to 81.9% (p less than 0.05), but was less successful in patients with heavier tumor burden, such as stage II disease or advanced loco regional disease in Waldeyer's ring (48.3% to 63.7%; p greater than 0.10 in stage II patients). In addition, in those who relapsed, the time and pattern of relapse were not altered by adjuvant CVP chemotherapy. This easily tolerated, mild adjuvant chemotherapy, we conclude, failed to prove significant in preventing relapse, especially in patients with heavier tumor burden.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

An experience with slit beam rotation therapy (SBRT).

A new rotation therapy technique using slit beams of 10 Mev X-rays (3.3 mm X 50 mm at isocenter FCD 100 cm) was developed. The dose distribution of a 360-degree rotation of the slit beam described above is similar to that of a 137-Cs needle. The axes of a 360-degree rotation of the slit beam were arranged to cover the target volume to produce a dose distribution similar to interstitial irradiation. This technique was named as the slit beam rotation therapy. Twenty patients who had radioresistant tumors or were difficult to control by conventional therapy have been treated with this technique, combined with or without conventional external beam irradiation, since 1982. Eight out of ten extracranial lesions showed good regression and a palliative effect was obtained without severe morbidity. A one year survival rate of 67% in six patients with glioblastoma multiforme was achieved by this method. Although the feasibility study is still in progress, this new treatment technique looks highly promising.

Brachytherapy↗
PubMedDate not supplied

CT-aided volumetry and prognosis in cervical carcinoma.

Since January 1981, 128 CT evaluations were systematically applied to 85 patients of histologically proven squamous cell carcinoma of the cervix uteri before and after external irradiation (i.e., at the beginning of intracavitary therapy). CT-measured cervical mass volume and mass-pelvic wall distance were analyzed in relation to prognosis, namely, local control at one year after irradiation and three-year survival. Regardless of clinical stage, CT-measured volume and mass-pelvic wall distance were revealed to be closely related to prognosis. In 46 patients whose cervical mass volume regressed to less than 48 cm3 after external irradiation, 44 (95.6%) were locally controlled for more than a year, and the three-year actuarial survival of this group was 71.6 + 6.2%. On the contrary, in those whose volume was over 48 cm3 at the end of external irradiation, only 3 out of 18 were locally controlled, and the three-year survival was 7.4 + 6.0. Mass-pelvic wall distance was also related to tumor control. CT was found to provide fairly objective, reproducible information for detecting the high-risk subgroup in cervical carcinoma under uniform treatment conditions.

Brachytherapy↗
PubMedDate not supplied

A "supralethal dose phenomenon" revealed by cancer of the maxillary sinus.

In this paper a so-called "supralethal dose phenomenon" is reported. Two groups of patients, all of whom were carrying proved squamous cell carcinoma of the same clinical stage in their maxillary sinuses, were compared after radiotherapy in our department. The radiotherapies applied to the two groups were very similar in terms of fraction number, treatment period, dose distribution and immobilization technique, but differed in dose, i.e., 5,500 cGy for one group of 9 patients and 5,750 cGy for the other group of 20 patients. The five-year survival rates of the two groups were 8/9 and 10/20, respectively, and the difference was statistically significant (p less than 0.05). All patients were observed for at least five years. Except for tumor stage, the status of the patients in the two groups, including primary site of the tumor in the sinus, patients' age and cause of death for the failed cases, are also discussed in detail.

Adult↗
PubMedDate not supplied

Coronary atherosclerosis reduced in patients with familial hypercholesterolemia after intensive cholesterol lowering with low-density lipoprotein-apheresis: 1-year follow-up study. The Osaka LDL-Apheresis Multicenter Trial Group.

To test the hypothesis that aggressive cholesterol lowering results in a rapid regression of coronary atherosclerosis, the effect of low-density lipoprotein (LDL)-apheresis for 1 year on coronary artery diameters was studied in patients with heterozygous familial hypercholesterolemia. LDL-apheresis was performed every 2 weeks in 13 patients with LDL-cholesterol levels > or = 200 mg/dL despite treatment with conventional dietary and drug therapies. Coronary arteriography was performed before and 1 year after the initiation of treatment. The LDL-cholesterol level was decreased by an average of 71% immediately after the initial LDL-apheresis and by 30% before the second apheresis. Such phasic changes were observed throughout the trial. Computer-assisted automated quantitative arteriograms analyzed 101 proximal coronary segments. The mean lumen diameter of angiographically normal sections of each segment was slightly but significantly increased from 2.93 +/- 0.89 mm at baseline to 3.05 +/- 0.93 mm at the follow-up arteriogram (P < 0.05); 54 of the 101 segments showed a lesion stenosed by 20% or more in diameter. The minimal diameter of individual lesions was also significantly increased from 2.17 +/- 0.67 mm to 2.36 +/- 0.76 mm (P < 0.05), and thus the diameter stenosis was significantly reduced from 32.3 +/- 10.5% to 28.2 +/- 12.1% (P < 0.05). It is concluded that 1 year of aggressive cholesterol lowering, using LDL-apheresis, can significantly reduce coronary atherosclerosis in patients with familial hypercholesterolemia.

Adult↗