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Biomedical subjects

T Hiraki

Publications and source records attributed to T Hiraki.

At least 37 records · Page 2Linked to original sources
PubMed1994

Tumour affinity of 203Pb-chloride: comparison with 67Ga-citrate and 201Tl-chloride.

The radionuclide 203Pb decays completely by electron capture to stable 203Tl with a half-life of 52 h. The primary radiation from the decay is gamma-ray radiation 280 keV (80%). 203Pb is produced easily from the natural metal thallium by the method described below. 203Pb-chloride is a promising imaging agent for tumour scanning because of the large retention value for tumour tissue and the small value for normal organs, but the large value for the kidney and bone is a shortcoming when considering it as an imaging agent. The retention value of 203Pb in tumour tissue is larger than that of 201Tl and smaller than that of 67Ga. The tumour/inflammatory lesion retention ratio for 203Pb is very large in comparison with those for 67Ga and 201Tl. 203Pb accumulates to a large extent in viable tumour tissue, and less in necrotic tumour tissue and in inflammatory lesion. Therefore, 203Pb-chloride is far better for visualization of viable tumour tissue than 67Ga and 201Tl if the large retention values for the kidney and bone were reduced.

Animals↗
PubMed1994

[A new neuromuscular transmission monitor (TOF Guard): the rationale behind the method and its clinical usefulness].

TOF Guard is one of the latest developments in the field of neuromuscular monitoring equipment. This system uses a miniature acceleration transducer (a piezo-electric ceramic wafer is used), simply fastened to the thumb with tape. The rationale behind the method is Newton's second law, stating that the acceleration is directly proportional to the force. In this study, authors assessed the accuracy of this system in clinical use, comparing with the force transducer method (Myograph 2000). The result showed that there was a very close positive correlation between the values of T1, TOF ratio and posttetanic count simultaneously measured by both methods. The coefficient of correlation was 0.96, and its significance level was P < 0.001. From the clinical view point, it is concluded that TOF Guard is very useful because of its accuracy and because the equipment is easy to handle, compact and of low price as a neuromuscular monitoring system for routine anesthesia.

Adult↗
PubMed1990

Mechanism of gallium 67 accumulation in inflammatory tissue.

The present study was undertaken to elucidate the accumulation mechanism of gallium 67 in inflammatory tissue. 67Ga accumulation in inflammatory tissue was observed by macro- and microautoradiogram. Permeability indices were calculated for serum albumin from blood vessels into inflammatory and normal tissue. Neutrophils and macrophages did not play a major role in 67Ga accumulation in the inflammatory tissue because 67Ga could hardly be detected in the sites in which neutrophils were crowded; the accumulation was concentrated in the intercellular space around these cells in the tissue. Permeability indices for inflammatory tissue were much greater than those for normal tissues. It is thought from the present study and previously reported results that 67Ga, together with plasma from permeable blood vessels, readily penetrates the inflammatory tissue and stays there by binding to the acid mucopolysaccharide present in the tissue.

Animals↗
PubMed1990

[A cephalometric, electromyographic and kinesiographic appraisal of a patient with mandibular prognathism and anterior openbite malocclusion before and after surgical orthodontic therapy: a case report].

A 19-year-old female patient with skeletal 3 and anterior openbite malocclusions was treated by a surgical orthodontic approach. A glossectomy was also performed. Cephalometric, electromyographic and kinesiographic records were taken before and after the treatment. The treatment results were as follows: 1. Esthetic improvement in facial profile and static alignment and intercuspation of teeth was obtained. 2. The dimension of the tongue with respect to that of the oral cavity proper measured on the lateral cephalograms revealed a value similar to that determined for the control data after the active treatment. 3. The proportion of reversed strokes with respect to the total chewing strokes increased at the completion of the active treatment both for the right- and the left-sided chewings, but it decreased during the retentive period. 4. At the initial stage, an earlier onset of the masseter muscle activity relative to the temporal muscle group was determined, while the temporalis muscles showed an earlier onset of activity in the postoperative phase. 5. The durations of chewing strokes became shortened in a postoperative phase both on the working and the balancing sides. This observation was particularly significant for the opening and the closing phases. In addition, the proportion of the duration of significant temporalis muscle activity with respect to that of the concomitant chewing stroke increased. 6. Anterior temporalis muscle and masseter muscle activity during clenching performance revealed a value similar to the control data. In summary, the current case suggests that the patients who receive surgical orthodontic treatment require sufficient time to obtain functional readaptation during the retentive period.

Adaptation, Physiological↗
PubMed1989

Determination of the lysosomal role in tumor accumulation of 67Ga by dual-tracer studies.

The lysosomal role in tumor accumulation of 67Ga was determined by dual-tracer (67Ga and 46Sc) studies. It became clear that 67Ga essentially did not accumulate in the tumor lysosome, and that the lysosome did not play a major role in tumor accumulation of 67Ga. In addition, it was revealed that tumor lysosome was hardly disrupted at all in some phases of fractionation procedures.

Animals↗
PubMed1989

Relation between the location of elements in the periodic table and various organ-uptake rates.

Fifty four elements and 65 radioactive compounds were examined to determine the organ uptake rates for rats 3, 24 and 48 h after i.v. injection of these compounds. They were prepared as carrier free nuclides, or containing a small amount of stable nuclide. Generally speaking, behaviors of K, Rb, Cs and Tl in all the organs were very similar to one another, but they differed from that of Na. Bivalent hard acids were avidly taken up into bone; therefore, uptake rates in soft tissues were very small. Hard acids of tri-, quadri- and pentavalence which were taken up into the soft tissue organs decreased more slowly from these organs than other ions. Soft acids such as Hg2+ were bound very firmly to the component in the kidney. Anions (with few exceptions), GeCl4 and SbCl3 were rapidly excreted in urine, so that the uptake rates in organs were low.

Animals↗
PubMed1989

[Levels for discharge to home and return to general ward of patients who received therapeutic dose of 131I based on external exposure dose].

This paper describes levels for discharge from hospital and return to general ward of patients treated with 131I. The level was determined by comparing the possible exposure dose to those individuals whom the patients are in daily contact with the annual dose limit for the public. The external exposure dose was calculated by using the data on the distance between the patient and individuals, length of the time spent at each distance, and each individual's age. The following levels were obtained: (1) For the patient to be discharged from the hospital, the maximum residual radioactivity should be less than 0.51 GBq if the distance from the patient in bedroom is 50 cm or more and the ages of her children are all over one year. No restriction is needed for the patient with residual radioactivity of 0.20 GBq. (2) For the patient to be returned to the general ward, the maximum residual radioactivities should be 28 MBq and 41 MBq, corresponding to the distance from the patient of 2.0 m and 2.5 m respectively. We established a method to analyze the factors affecting the level.

Adolescent↗
PubMed1988

Biodistributions of radioactive alkaline metals in tumor bearing animals: comparison with 201Tl.

The retention values for 42K, 86Rb and 134Cs in the tissues and blood were quite similar to those for 201Tl, but were very different from those for 22Na. In an experiment for subcellular fractionation of tumors, most of these nuclides were localized in the supernatant fraction, with small amounts in other fractions. The concentration ratios for these nuclides in each fraction were approximately constant regardless of the time after administration. Radioactive alkaline metals in the supernatant fraction of the tumor homogenate existed mostly as free ions and were bound to protein in other fractions of tumor tissue. These results were essentially the same as those for 201Tl. Ouabain suppression studies indicated that 201Tl is taken up into the tumor cells partly through Na+, K+-ATPase of their membranes. Ionic radii of alkaline metals and thallium were related to their blood and tumor retention values. This relationship suggested that monovalent cations whose ionic radii exceed 0.133 nm, and which exist as free ions in the tissue fluids, behave like the potassium ion. Potassium and K analogs (Tl, Rb, Cs) are avidly taken up into viable tumor cells whose Na+, K+-ATPase activity is elevated. Therefore, suitable radionuclides of K and K analogs can be excellent agents for visualization of viable tumor tissues.

Animals↗
PubMed1988

Distribution of 67Ga-citrate in abscess-induced rat by quantitative whole body autoradiography.

Distribution of 67Ga-citrate in inflammatory tissues was determined, and correlation between the 67Ga-uptake and capillary permeability of plasma from blood vessels in the inflammatory tissue was elucidated, by quantitative whole body autoradiography and double tracer autoradiography. The distribution of 67Ga in inflammatory tissue was similar to that of 131I-HSA and 99mTc-HSA, which were applied as an index to the plasma element. These results showed that the capillary permeability of plasma from blood vessels in the inflammatory tissue increases, and this causes the 67Ga-uptake.

Abscess↗
PubMed1988

Distribution of 103Ru-chloride in tumor-bearing animals and the mechanism for accumulation in tumor and liver.

Tumor uptake rates of 103Ru-chloride were smaller than those for 67Ga-citrate. In three tumors and liver, 103Ru in the mitochondrial fraction containing lysosome increased with time after the administration of 103Ru-chloride. The concentration of 103Ru was more dominant in connective tissue (especially inflammatory tissue) than in viable tumor tissue or in necrotic tissue. Quite large amounts of 103Ru in the tumor and liver were bound to the acid mucopolysaccharide whose molecular masses exceeded 40,000. Behavior of this nuclide was essentially similar to that of 67Ga.

Animals↗
PubMed1988

Unoperated adult cleft lip and palate: changes in form and function after operation.

This report describes the occlusion and craniofacial morphology--together with changes in tongue activity during swallowing before and after surgical correction--in a 26-year-old female patient with unilateral cleft lip and palate. Cross-bites were not observed before or after repair. Lateral cephalometric findings revealed a convex profile with a normal anterior cranial base length, a flat mandibular plane, and a short lower-anterior face height. Preoperative cineradiographic appraisal showed atypical tongue activity during swallowing. The dorsum of the tongue remained high to seal the cleft. The bolus was kept on the floor of the mouth and passed along the lateral margins of the tongue. The swallow duration, as determined by EMG of the tongue, was extremely long when compared with infant-operated cleft lip and palate patients and to noncleft subjects. Postoperatively, tongue function was similar to that in both cleft patients in whom closure was performed in infancy and to noncleft controls.

Adult↗
PubMed1987

67Ga accumulation in inflammatory lesion and its mechanism: comparison with malignant tumor.

The accumulation of 67Ga in inflammatory lesions increased with time after injection of turpentine oil and reached a plateau 5 days later. At that time the uptake in the lesions was larger than any other tissue, after ten days the lesion uptake decreased. In experiments using rats which had been kept for 5 days after subcutaneous injection of turpentine oil, the accumulation of 67Ga in inflammatory lesions increased with time until six days after administration of 67Ga-citrate. It is clear from this study that 67Ga is avidly accumulated in areas where the subcutaneous tissue is infiltrated with neutrophils and macrophages, that it is not accumulated at the sites in which neutrophils are crowded, that nuclear material, mitochondria, lysosomes and microsomes do not play a major role in 67Ga accumulation in the lesion and that the main binding acid mucopolysaccharide in the lesion is a acid mucopolysaccharide which is none of the following: keratan sulfate, heparan sulfate, heparin, or chondroitin sulfate A, B or C. It is presumed that the main 67Ga binding acid mucopolysaccharide is keratan polysulfate (or other oversulfated acid mucopolysaccharides).

Animals↗
PubMed1987

Biodistributions of 201Tl in tumor bearing animals and inflammatory lesion induced animals.

The accumulation of 201Tl in tumor and inflammatory tissues were small. However, this nuclide showed a high concentration in viable tumor tissue, less in connective tissue (containing inflammatory tissue), and was not seen in necrotic tumor tissue regardless of the time after administration of 201Tl(I)-chloride. In inflammatory lesions, 201Tl accumulated in subcutaneous tissue infiltrated with neutrophils and macrophages, and quite large amounts of this nuclide were accumulated in subcutaneous tissue and sites where neutrophils were crowded. Most 201Tl existed in a free form in the fluid of tumor and inflammatory tissues regardless of the time after administration. A small amount of this nuclide was localized in the nuclear, mitochondrial and microsomal fractions in these tissues, and the nuclide was bound to protein in these fractions. The distribution of 201Tl(III)-chloride in tumor bearing animals was essentially the same as that of 201Tl(I)-chloride.

Animals↗
PubMed1987

Distribution of 46Sc and 51Cr in tumor-bearing animals and the mechanism for accumulation in tumor and liver.

Tumor uptake rates, concentrations in mitochondrial fraction (containing lysosome) of liver and tumors, avid accumulations in connective tissue (especially inflammatory tissue) and binding substances in these tissues for 46Sc3+ and 51Cr3+ were essentially similar to those for 67Ga3+, 111In3+, 169Yb3+, 167Tm3+, 95Zr4+ and 181Hf4+. However, the main binding substance of 46Sc3+ and 51Cr3+ in tumor and liver was the acid mucopolysaccharide (as described concerning 95Zr and 181Hf) whose molecular weight exceeded 40,000, although the main binding substance of 67Ga3+, 111In3+, 169Yb3+ and 167Tm3+ was the acid mucopolysaccharide with a molecular weight of about 10,000.

Animals↗