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Biomedical subjects

K Hamamoto

Publications and source records attributed to K Hamamoto.

At least 91 records · Page 5Linked to original sources

Assessment of systolic thickening with thallium-201 ECG-gated single-photon emission computed tomography: a parameter for local left ventricular function.

We measured left ventricular (LV) systolic thickening expressed as a systolic thickening ratio in 28 patients, using 201Tl ECG-gated SPECT. Five normals, 15 patients with prior myocardial infarction, 5 with hypertrophic cardiomyopathy, and 3 with dilated cardiomyopathy were studied. The systolic thickening ratio was calculated as [(end-systolic--end-diastolic pixel counts) divided by end-diastolic pixel counts], using the circumferential profile technique of both end-diastolic and end-systolic short axial images. Functional images of the systolic thickening ratio were also displayed with the "bull's-eye" method. The mean systolic thickening ratio thus calculated were as follows: normals, 0.53 +/- 0.05 (mean +/- 1 s.d.); non-transmural prior myocardial infarction, 0.33 +/- 0.09; transmural prior myocardial infarction, 0.14 +/- 0.05; hypertrophic cardiomyopathy in relatively nonhypertrophied areas, 0.56 +/- 0.11; hypertrophic cardiomyopathy in hypertrophied areas, 0.23 +/- 0.07; and dilated cardiomyopathy, 0.19 +/- 0.02. The systolic thickening ratio analysis by gated thallium SPECT offers a unique approach for assessing LV function.

Cardiomyopathy, Dilated↗

[A case of radiation-induced mucoepidermoid carcinoma of the lung following radiotherapy for pulmonary metastasis of Wilms' tumor].

Radiotherapy is one of the main therapeutic methods for malignant tumors, but on the other hand it can also induce new malignant tumors. Recently, we experienced a case of a 22-year-old woman with triple cancers (Wilms' tumor, thyroid cancer and mucoepidermoid carcinoma of the lung). She had been treated repeatedly for right-sided pulmonary metastases from the Wilms' tumor. The last cancer arose from a different organ in the field irradiated to treat the first cancer, after a latent period of about 20 years. Therefore, this case is classified as highly probable radiation-induced cancer (A-1 group) by the diagnostic criteria for radiation-induced cancer proposed by Sakai et al. Second cancers (radiation-induced cancers) mainly consist of soft tissue sarcomas, leukemias, skin cancers, urinary bladder cancers, large bowel cancers and other tumors. The occurrence of mucoepidermoid carcinoma of the lung as a radiation-induced tumor had not been reported. This patient also showed poor growth of the right breast and marked deformity of the right side of the thorax as late damage from irradiation. We must make efforts to decrease late damage from radiotherapy for pediatric cancers.

Adult↗

Tumor-antigen 4. Its immunohistochemical distribution and tissue and serum concentrations in squamous cell carcinoma of the lung and esophagus.

The immunohistochemical distribution and concentrations of tumor-antigen 4 (TA-4) in tissues and serum were determined in patients with benign and malignant diseases, including 27 patients with squamous cell carcinoma (SCC; 15 in the lung and 12 in the esophagus). Tumor-antigen 4 immunoreactivity was present in the cytoplasm of many SCC tissues, especially in the hyperparakeratotic region, and in the cytoplasm of differentiated squamous cells of the intermediate layer of normal epithelia of various organs, but not in those of other types of lung cancers or benign pulmonary diseases. Consistent with the results of immunostaining, the TA-4 concentrations in SCC tissues of the lung, esophagus, and normal squamous epithelia were much higher than in those of lung cancer other than SCC, benign pulmonary diseases, normal lung, and submandibular gland tissues. The TA-4 concentration in SCC tissue tended to increase with increasing grades of differentiation. Serum TA-4 was elevated in 15 of 27 patients with SCC but in no patients with other types of lung cancer or benign diseases. These results indicate that TA-4 is an antigen related to the differentiation of squamous cells and that tumor cells of SCC can release a large amount of TA-4 into circulation whereas normal squamous epithelia cannot.

Aged↗

[Radiation therapy for unresected gastric lymphoma].

Six consecutive patients with unresected gastric lymphoma which were treated by radiation therapy between November, 1976 and March 1989 were reviewed. Radiation therapy was performed using involved fields, total radiation dosages of which ranged from 25.2 to 36 Gy (mean, 29.3 Gy). Five out of the 6 patients were treated with chemotherapy combined with radiation. Regimen of the chemotherapy was CHOP (cyclophosphamide, adriamycin, vincristine and prednisone) in most cases. Three out of the 6 underwent probe laparotomy, but the tumors were diagnosed as unresectable due to locally invading the adjacent structures. They were treated by chemo-radiotherapy and 2 of them are surviving as of the present study (40 and 116 months). The other 3 patients were diagnosed as with clinical stage IV disease and 2 of them were successfully treated with chemo-radiotherapy (21 and 66 months, surviving). These data suggest that unresected gastric lymphomas, which are locally advanced or stage IV disease, are treated by chemoradiotherapy with high curability without any serious complications.

Adult↗

[The role of gallium-67 citrate scintigraphy in gastro-intestinal malignant lymphoma].

To evaluate the clinical usefulness of gallium-67 scintigraphy in the detection of the gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, gallium-67 scintigraphy was reviewed on 24 cases (25 lesions; stomach in 20, ileum in 2, and terminal ileum and/or cecum in 3). Twenty-three out of the 25 lesions (92.0%) were detected by gallium-67 scintigraphy, while barium study could detect all of the 25 lesions. The sizes of the gallium-67 negative 2 lesions were the smallest of all (2.5 and 3.0 cm). The tumor size was considered to the most important factor in the detection by gallium-67 scintigraphy, while the histological classification and the location of the tumor were not related to its detectability. Findings in follow-up gallium-67 scintigraphy after therapy on 10 cases were correlated well with the therapeutic effects. These data suggest that gallium-67 scintigraphy is useful for the detection of GI involvement of NHL and for the assessment of therapeutic effects.

Adult↗

High density culture of hybridoma cells using a perfusion culture vessel with an external centrifuge.

The influence of centrifugal force on the growth of cells was examined by exposing the cells of the mouse-human hybridoma X87 line to centrifugal force (100-500 G) for ten minutes twice a day and comparing the static culture with that of unexposed cells. In this experiment, both cell proliferation and specific antibody productivity were independent of the centrifugal effect, and gave the same results as in the case of no exposure to centrifugal force. High density cultivation of the mouse-human hybridoma X87 line was obtained by a perfusion system where the cells were separated from the culture medium by continuous centrifugation. In the serum-free culture, the maximum viable cell density exceeded 10(7) cells/ml, and monoclonal antibody was stably produced for 37 days. The results in this culture were equivalent to those obtained by intermittent centrifugal cell separation from the culture medium, and separation by gravitational settlement.

Animals↗

The role of gallium 67 imaging in non-Hodgkin's lymphoma of the gastrointestinal tract.

To evaluate the clinical usefulness of gallium 67 imaging in the detection of gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, images were reviewed in 24 cases (25 lesions: stomach, 20; ileum, 2; and terminal ileum and or cecum, 3) and were compared using barium studies and, in 16 cases, computerized tomography (CT). In all, 23 (92.0%) of the 25 lesions were detected by 67Ga citrate imaging, the barium studies detected all 25, and CT detected 15 of 16 lesions (93.8%). The two lesions not identified by imaging and the one not found by CT were the smallest of all. In 2 (8.7%) of the 23 lesions positively identified by 67Ga-citrate imaging, both CT and imaging revealed the extent of the tumor more accurately than did the barium studies. In all but one of the patients, a close correlation existed between the imaging results and the therapeutic effects. These data suggest that 67Ga imaging is useful in conjunction with CT and barium studies for the detection of GI NHL and for the assessment of both the spatial extent of disease and the therapeutic effects, although a lack of 67Ga uptake after therapy does not always indicate a good therapeutic effect.

Barium Sulfate↗

Single photon emission computed tomography (SPECT) using N-isopropyl-p-(123I) iodoamphetamine (IMP) in the evaluation of patients with epileptic seizures.

To evaluate the clinical usefulness of IMP SPECT in the diagnosis of epilepsy, 6 normals and 52 patients in the interictal phase were studied. Thirty min after an intravenous injection of 111 MBq IMP, SPECT was performed using a rotating gamma camera. Of 21 patients with simple partial seizures, a localized decrease of uptake was shown in 16, and an increase in 3. Topologically, these findings corresponded well to the ictal symptoms. Nine of 13 patients with localized epileptic EEG had a good correspondence between the findings on EEG and IMP SPECT. In 20 of 23 with complex partial seizures, the coronal images showed laterality of uptake in the temporal lobes, whereas the CT was normal in 14. However, these findings on IMP SPECT agreed with the EEG in the temporal leads in only 5 cases. Of 8 patients with primary generalized seizures, a diffuse cerebral decrease was shown in 3 of 4 patients with convulsive seizures (grand mal), and a normal uptake in 3 of 4 patients with non-convulsive seizures (petit mal). However, 2 patients showed a localized decrease, therefore, we determined that they suffered from partial seizures evolving to secondarily generalization. From these data, we concluded that IMP SPECT could be a useful method in the diagnosis of epilepsy.

Adolescent↗

Methods for measuring the renal uptake rate of 99mTc-dimercaptosuccinic acid (DMSA): a comparative study.

A comparative study of the renal uptake rate of 99mTc-dimercaptosuccinic acid (DMSA) was performed using a phantom study and clinical data from 100 patients (200 kidneys) with a variety of renal diseases. The measurement methods for renal uptake rate studied here include a posterior-view method, a conjugate-view method, and a method using single photon emission computed tomography (SPECT). The renal uptake rates obtained by the posterior-view method significantly (P less than 0.001) depended on kidney depth correction. With the SPECT method, the cut-off level for delineating the kidney was changed according to the background count ratio using the results of the phantom study. The renal uptake rates obtained by the SPECT method correlated significantly (P less than 0.001) with those obtained by other methods, and there were no significant differences as compared with those obtained by the conjugate-view method. An analysis of error with the above methods indicated that the error relating to the sensitivity to body thickness was smallest for the SPECT method and greatest for the posterior-view method. In terms of measurement of renal uptake rate only, the conjugate-view method is considered the most useful because it needs no kidney depth correction and requires very little additional effort or examination time.

Female↗

An immunoradiometric assay of tumour-antigen 4 (TA-4): a comparison with conventional radioimmunoassay.

The serum level of tumour-antigen 4 (TA-4) was measured in 181 patients with squamous cell carcinoma (SCC) of various organs (71 lung, 24 uterus, 16 oesophagus, 64 head and neck and six skin), 34 patients with other types of lung cancer and 35 patients with benign diseases. To compare the results with those obtained by the conventional competitive radioimmunoassay (RIA) using a polyclonal antibody, a new immunoradiometric assay (IRMA) method was used which has recently been developed using two monoclonal antibodies raised to different epitopes of TA-4. Both methods provided essentially the same results: the serum TA-4 levels were high in patients with SCC of various organs when compared with those of healthy controls and patients with other types of lung cancer or benign diseases. However, the positive ratios assessed as the percentage of patients with elevated serum TA-4 levels were higher with the IRMA method than with the RIA method in SCC of all organs, as much as 2-3 times higher in SCC of the larynx, tongue and pharynx. In contrast, in patients with benign diseases or other types of lung cancer, there was no difference in the positive ratios between the two methods. This was largely due to the improvement in sensitivity and accuracy of assay with the new method, which resulted in a decrease in the normal value in healthy controls. It was concluded that with the new IRMA method using monoclonal antibodies, the diagnostic detectability of serum TA-4 is enhanced in SCC of all organs.

Antigens, Neoplasm↗

Serum CA125 level is a good prognostic indicator in lung cancer.

The serum CA125 level was determined by a one-step immunoradiometric assay method in patients with lung cancer. Increased serum CA125 levels were observed in 37.8% of patients with squamous cell cancer, in 30.0% of those with adenocarcinoma and in 60.0% of those with small call cancer. Most patients with increased serum CA125 levels were in stages 3 or 4. Patients with pleural effusions or ascites showed high serum CA125 levels. The survival time was significantly shorter in patients with increased serum CA125 levels than in those within normal limits. Among patients with advanced disease (stages 3 and 4), an increased serum CA125 level was again a poor prognostic factor (P less than 0.01). The existence of a pleural effusion did not correlate with the survival time. We conclude that CA125 is a good indicator of disease extent and serum levels correlate to the length of survival.

Adult↗

A method for computing the derivative of noisy time-activity curves and its application to radioisotope dynamic analysis.

A method for computing the slope or the derivative of time-activity curves containing statistical fluctuations is described. The algorithm presented employs digital differentiation as a digital filter. In designing an effective differentiating filter the Chebyshev-type min-max method and Remez exchange algorithm are used to minimise the weighted Chebyshev error. The validity of this method has been investigated using computer-based Monte Carlo simulation. Renogram curve analysis is presented as an example of an application of this method to radioisotope dynamic analysis. The ratio of the bilateral slopes of the renogram's second segments estimated using this method correlated well with the renal plasma flow ratio (r = 0.97, n = 16). The functional images of the slope of the renogram's second segments have been constructed and ascertained to be clinically useful. This method is considered to provide a powerful tool for extraction of quantitative information both in research and in routine nuclear medicine clinical work, and may be useful in various other fields.

Algorithms↗

Pharmacokinetic data of bromofenofos in calves.

Bromofenofos (BF) was administered orally to six calves at a dose of 12 mg/kg and the concentrations of BF and its metabolite dephosphate bromofenofos (DBF) in plasma were determined using a high-performance liquid chromatographic method. DBF reached maximum concentration of 45.9 +/- 16.3 micrograms/ml, which occurred at 1.3 +/- 0.4 days. The elimination half life was calculated to be 1.8 +/- 0.3 days and the area under the plasma concentration versus time curve was 185.1 +/- 49.4 micrograms.day/ml. The ultrafiltrate of plasma samples revealed no free metabolite, indicating a binding of greater than 99% to plasma protein. DBF disappeared from plasma in all calves 21 days after administration. No BF was detected in plasma at any time.

Administration, Oral↗

Fetal uptake of intraamniotic digoxin in sheep.

To explore the possibility that intraamniotic administration of digoxin is an effective treatment regimen for fetal tachyarrhythmia, we injected digoxin into the amniotic fluid cavity of pregnant sheep and examined the time course of digoxin distribution to the fetal and maternal plasma compartments. Animals were studied in two groups according to digoxin dosage: 0.7-1.8 nmol/kg fetal body wt in the high-dose group (n = 6) and 0.1-0.6 nmol/kg fetal body wt in the low-dose group (n = 14). Within 1 h, plasma digoxin concentrations in the high-dose and low-dose groups were 18.2 +/- 15.0 nmol/L and 2.7 +/- 0.8 nmol/L, respectively (values are expressed as mean +/- SD). At 6 h digoxin concentrations were 13.8 +/- 7.0 and 3.1 +/- 0.9 nmol/L, and at 24 h they were 2.3 nmol/L (n = 1) and 1.8 +/- 1.2 nmol/L, respectively. Peak maternal digoxin levels were about one-tenth fetal values in the high-dose group and undetectable in the low-dose group. Fetal digoxin concentrations were significantly greater in the descending aorta than in the umbilical vein (p less than 0.02). Fetal arterial blood pressure and heart rate were not significantly different from control at any time after digoxin administration. These results demonstrate that digoxin is rapidly taken up into the fetal circulation from the maternal amniotic cavity. The exact mechanism whereby this occurs is unknown, but transplacental transfer from the maternal circulation is not involved. Our findings suggest that intraamniotic administration of digoxin may be an alternative treatment for fetal tachyarrhythmias when direct administration of antiarrhythmic agents is ineffective or produces maternal toxicity.

Amnion↗

Diffuse gallium-67 uptake in radiation pneumonitis.

To evaluate the clinical usefulness of Ga-67 imaging for the assessment of radiation pneumonitis, 12 patients who had developed radiation pneumonitis after receiving radiotherapy alone for non-small-cell lung cancer from 1979 through 1988 were reviewed. Diffuse bilateral Ga-67 uptake occurred in 5 out of the 12 cases; in the other 7 cases, Ga-67 uptake was confined to the irradiation lung. Conversely, chest radiography showed infiltrates only in the irradiated lung. Histopathology of the lung in four out of the five cases that showed diffuse Ga-67 uptake in the lung, however, revealed that the lung outside the radiation field with Ga-67 uptake was consistent with interstitial pneumonitis induced by radiation. These results suggest that radiation pneumonitis could extend beyond the irradiated lung and that Ga-67 imaging is more useful than chest radiography for the assessment of the spatial extent of radiography pneumonitis.

Aged↗