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Biomedical subjects

S Yoshioka

Publications and source records attributed to S Yoshioka.

At least 145 records · Page 8Linked to original sources
PubMed1996

[A case of central pain observed in medical medullary infarction].

A 45-year-old man had typical features of the left medial medullar syndrome which were left tongue paralysis, right hemiparesis, and right disturbance of touch and deep sensation sparing the face. He complained of hyperpathia, numbness and pain of the right body and limb sparing the face. MRI disclosed left upper medial medullary infarction, and cerebral angiography revealed occlusion of the left vertebral artery before the posterior inferior cerebellar artery. In general, the touch and deep sensation are carried through the medial lemniscus located in the medial medulla, therefore central pain is not considered to be induced by the medial medullary lesion. But tingling and numb sensation were sensory symptoms in our patient and the cases previously reported. If spinocervicothalamic tract related to touch and pain sensation has been well developed, it is suspected that central pain is induced by disturbance of the tract.

Cerebral Infarction↗
PubMed1996

[Analysis of contributing factors with high renal uptake of 99mTc-MDP after anti-cancer chemotherapy including cisplatin].

We studied the effect of anti-cancer chemotherapy including cis-platin (CDDP) on renal high uptake of 99mTc-MDP using renal accumulation index (RAI) which was defined as a ratio of the densities between kidneys and lumbar bodies. We analyzed 21 cases who received bone scintigraphy within 30 days after chemotherapy. High RAIs were observed in 15 cases (71.4%). We compared the relationship between the RAI and time interval of CDDP administration and bone scintigraphy, total dose of CDDP, BUN and age. High RAIs were inversely related to the time interval and no patient showed high RAI when bone scintigraphy were studied later than 17 days after chemotherapy. BUN level were related to RAI. But, dose of CDDP and ages were unlikely responsible for the RAI values in this study. We summarized that high renal uptake of 99mTc-MDP was likely to be due to short time interval after chemotherapy.

Adult↗
PubMed1996

[Development of a new statistical evaluation method for brain SPECT images].

The purpose of this study was to develop a new statistical evaluation method for Brain SPECT images. First, we made normal brain image databases using 99mTc-ECD and SPECT in 10 normal subjects as described previously. Each SPECT images were globally normalized and anatomically standardized to the standard brain shape using Human Brain Atlas (HBA) of Roland et al. and each subject's X-CT. Then, mean and SD images were calculated voxel by voxel. For the next step, 99mTc-ECD SPECT images of a patient were obtained, and global normalizing and anatomical standardization were performed as the same way. Then, a statistical map was calculated as following voxel by voxel; (P-Mean)/SD x 10 + 50, where P, Mean and SD indicate voxel value of patient, mean and SD images of normal databases, respectively. We found this statistical map was helpful for clinical diagnosis of brain SPECT studies.

Brain↗
PubMed1996

[Shelf-life estimation of pharmaceutical products by matrixing].

The shelf-life estimates of pharmaceutical products obtained by matrixing are compared with those obtained by ordinary analysis, using stability data generated by the Monte Carlo method. The effect of the variation in stability due to different packaging and formulations on the shelf-life estimates is described. Analysis of variance is proposed for the evaluation of shelf-life estimates obtained by matrixing. The relationship between the power of the test and the significance level is discussed as well as the effect of assay error on the power of test.

Analysis of Variance↗
PubMed1995

Activity in the human primary motor cortex related to arm and finger movements.

With the purpose of mapping representations of the finger and proximal arm in the human primary motor cortex (MI), we measured regional cerebral blood flow (rCBF) in eight right-handed normal volunteers during self-paced finger and proximal arm movements. Each movement activated two different fields in MI, one located deep in the anterior lip of the central sulcus and the other relatively close to the surface of the precentral gyrus. Arm fields were located higher than finger fields. A superficial arm field and a deep finger field partially, overlapped. The results indicate that there are two spatially separate motor representations of the finger and proximal arm in the human MI.

Adult↗
PubMed1995

Water mobility in poly(ethylene glycol)-, poly(vinylpyrrolidone)-, and gelatin-water systems, as indicated by dielectric relaxation time, spin-lattice relaxation time, and water activity.

The mobility of water molecules present in poly(ethylene glycol) (PEG)-, poly(vinylpyrrolidone) (PVP)-, and gelatin-water systems was determined by dielectric relaxation and 17O NMR spectroscopy. Water activity was also measured. Dielectric relaxation spectra indicate that all the polymer systems studied contained water exhibiting a dispersion at a frequency > 10(9) Hz; in other words, water with high mobility close to that of bulk water. The dielectric relaxation time of the highly mobile water increased as polymer concentration increased. The PVP- and gelatin-water systems also contained water exhibiting a dispersion at a frequency < 10(9) Hz, which can be considered to be "bound water" with a restricted mobility because of its association with polymer molecules. Dielectric relaxation spectroscopy was used to determine water mobility separately for the populations of highly mobile water and bound water, whereas NMR relaxation spectroscopy was used to determine the average mobility of both populations. The spin-lattice relaxation time of water in these polymer-water systems showed a deviation from the isotropic two-state model. Dielectric relaxation data indicate that this deviation can be ascribed to variations in the relaxation time of highly mobile water caused by a change in polymer concentration. The dielectric relaxation time of highly mobile water in the gelatin system did not change with a change in polymer concentration to the extent that it did in the PEG and PVP systems. This result is consistent with a slight change in water activity of the gelatin system with increasing polymer concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1995

Error analysis of table look-up method for cerebral blood flow measurement by 123I-IMP brain SPECT: comparison with conventional microsphere model method.

While N-isopropyl-p-[123I]iodoamphetamine (IMP) is commonly used as a flow tracer, significant clearance from the brain causes underestimation of CBF as compared with true CBF when conventional microsphere model analysis is applied. We previously reported a simple "table look-up" method for CBF measurement using IMP taking into account this clearance effect. The method is based on a two-compartment model, the K1 (corresponding to CBF) and k2 constants being obtained from a table from the ratio of the 1st SPECT (40 min) to the 2nd SPECT (180 min) counts. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, this approach was compared with conventional microsphere model analysis. For 30 subjects, the latter method entailed 8 min continuous arterial blood sampling after IMP infusion and the use of SPECT data at the end of this period, calibrated by a count ratio of 8 min/40 min planar images of whole brains. A good correlation was observed between the two methods (r = 0.88), but an overestimation of table look-up method CBF as compared with microsphere model CBF was observed contrary to theoretical predictions. Limitations in the estimation of SPECT data at 8 min, obtained with SPECT data at 40 min for calibration of the count ratio of 8 min/40 min whole brain planar images, might be responsible for this.

Amphetamines↗
PubMed1995

Suppression of hepatic gluconeogenesis in long-term Troglitazone treated diabetic KK and C57BL/KsJ-db/db mice.

The orally effective antidiabetic agent Troglitazone (CS-045) exerts hypoglycemic effects in various insulin-resistant obese and/or diabetic animals. Since increased hepatic gluconeogenesis is a major cause of hyperglycemia in these diabetic animals, we evaluated the effect of long-term Troglitazone treatment on hepatic gluconeogenesis. Troglitazone was administered for 7 days to normal ddY mice, diabetic KK mice, diabetic C57BL/KsJ-db/db mice, and its heterozygote, db/+ mice, as a 0.1% or 0.2% food admixture. Troglitazone significantly decreased plasma glucose in diabetic KK and db/db mice, but not in normal ddY and db/+ mice. 14C incorporation into blood glucose from NaH14CO3 was measured to assess hepatic gluconeogenesis in diabetic KK and normal ddY mice. Hepatic gluconeogenesis was significantly increased in diabetic KK mice (P < .01) as compared with normal mice, and was significantly suppressed (P < .05) after 7 days of Troglitazone treatment (approximately 200 mg/kg/d). Glucose-6-phosphate (G6P) and fructose-6-phosphate (F6P) were significantly decreased but fructose-1,6-bisphosphate (FBP) was not significantly increased in the liver of diabetic db/db mice treated with Troglitazone for 7 days (approximately 80 mg/kg/d) as compared with control db/db mice. These changes in G6P, F6P, and FBP corresponded with the activity of fructose-1,6-bisphosphatase (Fru-1,6P2ase) and 6-phosphofructo-1-kinase (6-PF-1K), which determined the content of F6P and FBP. Namely, Fru-1,6P2ase was significantly decreased in Troglitazone-treated db/db mice as compared with control mice, whereas 6-PF-1K activity was not affected by Troglitazone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Increased stabilizing effects of amphiphilic excipients on freeze-drying of lactate dehydrogenase (LDH) by dispersion into sugar matrices.

PURPOSE: The stabilizing effect of amphiphilic excipients and sugars against protein inactivation during freeze-drying was studied in relation to their physical states in freeze-dried cakes. METHODS: Physical states of amphiphilic excipients were studied by powder X-ray diffractometry and differential scanning calorimetry (DSC). Stabilizing effects of excipients were studied using lactate dehydrogenase (LDH) as a model protein. RESULTS: Although poly(ethylene glycols) (PEGs) 1000 to 2000 crystallized when freeze-dried alone, the addition of sugars decreased their crystallinity by dispersing PEG into sugar-dominant matrices. Sugars species, molecular weight of PEGs, and buffer concentration also affected the crystallinity of PEGs. Sugars also dispersed some of other amphiphilic excipients, which tended to crystallize or become "microscopically liquid" when freeze-dried without sugar. Only the amphiphilic excipients that remained amorphous solid state protected the enzyme during freeze-drying in the absence of sugars. However, combinations of sucrose and all the amphiphilic excipients studied increased the stabilizing effects markedly. The remaining activities were greater than the sum of their individual ones. CONCLUSIONS: Various amphiphilic excipients are good stabilizers for freeze-drying of proteins when dispersed into sugar-dominant matrices.

Dose-Response Relationship, Drug↗
PubMed1995

Pulmonary nodules in patients with a history of radical nephrectomy for renal cell carcinoma.

BACKGROUND: Nine patients with a history of radical nephrectomy for renal cell carcinoma underwent surgical removal of newly detected pulmonary nodules at the Hiroshima University Hospital. Six patients had metastatic lung tumors two patients had bronchogenic primary carcinomas and one had a granulomatous infection. METHODS: To determine if any characteristics can distinguish a new primary carcinoma from metastatic renal cell carcinoma, we reviewed the nine patients described above. The patients with pulmonary metastases and those with new primary lung cancers did not differ in age, sex, history of smoking, clinical stage and pathological findings of the renal primary site, on the location and size of the pulmonary nodules. RESULTS: Only the interval between the nephrectomy and the appearance of the new pulmonary lesion may be a predictive factor. This interval was 48 and 51 months for the patients with new primary lung cancers but varied from 0 to 39 months for the patients with metastatic renal cell carcinoma. A solitary nodule had an equal chance of being metastatic or primary. CONCLUSIONS: These results indicate that a solitary nodule that is detected at a longer interval after radical nephrectomy may be a new primary lung cancer. Once new pulmonary nodules are identified in a patient with a history of radical nephrectomy for renal cell carcinoma, surgical excision is required for a final diagnosis before initiating therapy for metastases.

Adult↗
PubMed1995

Mass screening and age-specific incidence of neuroblastoma in Saitama Prefecture, Japan.

PURPOSE: To provide the population-based incidence rate of neuroblastoma and to determine the effect of mass screening on the annual age-specific incidence of the tumor in Saitama Prefecture, Japan, from 1981 to 1992. METHODS: Data on screened infants and patients detected by the screening were obtained from the records of the Prefectural Screening Center. Data on neuroblastomas in this area were obtained from the Children's Cancer Registry of the Saitama Prefectural Government (Prefectural Registry) and from the Japan Children's Cancer Registry (National Registry). Population data were obtained from the Prefectural Census. Mass screening for 6-month-old infants was performed by qualitative assessment of urinary vanillylmandelic acid (VMA) from June 1981 to September 1989 and by quantitative measurement of VMA/creatinine (Cre) and homovanillic acid (HVA)/Cre from October 1989 to December 1992. RESULTS: Between 1981 and 1992, 199 cases of neuroblastoma, which include 74 cases detected by mass screening, were identified in Saitama Prefecture. The incidence rate for children under 15 years of age increased from 6.4/10(6) to 20.1/10(6), that for children 0 to 4 years of age increased from 17.0/10(6) to 64.1/10(6), and that for infants under 1 year of age increased from 27.9/10(6) to 260.4/10(6) during these 12 years. No significant reduction in the incidence rate was observed for children over 1 year of age. CONCLUSION: The incidence rate for children under 15 years of age increased with mass screening. The rate for infants was sharply increased, with no corresponding decrease in the rate for children at older ages. These data suggest that there is a subset of neuroblastoma that can be detected by mass screening at 6 months of age but would not be diagnosed later clinically.

Adolescent↗
PubMed1995

[Amygdaloid kindling in variously aged infant rats and rekindling after maturation: epileptogenesis and its persistence].

To study amygdaloid kindling in variously aged infant rats and rekindling development after their maturation, 34 male Wistar rats were subjected to initial kindling 13 days after birth (13-day-old group, 9 rats), 16 days after birth (16-day-old group, 9 rats), 18 days after birth (18-day-old group, 7 rats), or 26 days after birth (26-day-old group, 9 rats). Each group received reoperation on the 70th day, and was subjected to rekindling 5 days after operation. Also, a control group of mature rats was initially kindled at the age of 75 days and rekindled after 2 months (75-day-old group, 11 rats). The obtained results are summarized as follows. I. Results of initial kindling: (1) a significant positive correlation was found between the age of the 4 groups of rats and the after-discharge threshold of infant rats (p < 0.05), (2) significant correlations were not found between the age of the 4 groups of infant rats and the stimulation numbers inducing C0-2 and C0-4 stage symptoms, (3) a significant positive correlation was found between the age of the 4 groups of infant rats and the stimulation number inducing C3-4 symptoms (p < 0.05). II. Results of rekindling: (1) significant negative correlations were found between the age of the 4 groups at initial kindling and the stimulation numbers inducing C0-2, C3-4 and C0-4 symptoms (p < 0.05-0.0001). III. Ratio of initial kindling and rekindling: (1) significant negative correlations were found between the age at initial kindling and the C0-2 and C0-4 stimulation number ratios (p < 0.00001), (2) a negative but not significant correlation was found between the C3-4 stimulation number ratio and age at initial kindling. These results suggest that in infant rats amygdaloid excitability is stronger, when the younger the rat, and that the later in the infant period the epileptogenesis is acquired, the stronger is it preserved even after maturation as high amygdaloid excitability.

Aging↗
PubMed1995

[A new 3-dimensional head fixation device for brain imaging].

We have developed a new head fixation device for studies of brain function. This device was designed to immobilize subject's heads during image scanning and to precisely reproduce the head position for two different imaging modalities such as MRI and PET. The device consists of a plastic frame, a pillow filled with beads of styrene foam, and a face mask of thermoplastic resin which was originally intended for application in radiotherapy. A bridge for biting was incorporated into the mask for stable fixation. The device enables immobilization of subject's heads with good reproducibility of position at the practical level. Our results indicate that this head fixation system is useful for fixation of head during activation studies using PET.

Brain↗
PubMed1995

[Normal cerebral perfusion of 99mTc-HMPAO brain SPECT--evaluation by ananatomical standardization technique].

Single photon labeled tracer 99mTc-hexamethylpropylene amine oxime (HMPAO) has been used for rCBF studies by SPECT. However, normal perfusion pattern of this agent still remains unclear. The purpose of this study was to investigate normal 99mTc-HMPAO SPECT image voxel by voxel. Eighteen male subjects without any prior or present history of medical illness participated in this study. All SPECT images were globally normalized to 100 count/voxel. Each subject had an X-ray CT scan at the same day of SPECT measurement. All subjects had normal X-ray CT scans. The standard anatomical structures of the computerized brain atlas of Roland et al. were fitted to X-ray CT images of a subject by linear and non-linear parameters. These parameters were subsequently used to transform SPECT images of the subject. After the anatomical standardization, mean and SD images of eight standardized images were calculated voxel-by-voxel basis. In the mean image, following structures showed relatively higher radioactivity; the putamen, the cerebellum, and the frontal lobe. In addition, the occipital lobe, parietal lobe, frontal lobe, and the putamen showed large degree of SD. Anatomical standardization of SPECT images may be useful as a reference to diagnose and evaluate various brain disorders.

Adult↗
PubMed1994

Functional anatomy of taste perception in the human brain studied with positron emission tomography.

Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) in 10 normal volunteers with the purpose of measuring rCBF changes related to taste physiology. Discrimination of 0.18% saline from pure water was associated with significantly increased rCBF values in the thalamus, the insular cortex, the anterior cingulate gyrus, the parahippocampal gyrus, the lingual gyrus, the caudate nucleus, and the temporal gyri. The results indicate that rCBF changes in these structures may reflect oral exposure to salt.

Adolescent↗
PubMed1994

[Preliminary clinical applications of asymmetric screen-film systems in chest radiography].

The physical imaging properties of asymmetric systems and a conventional system were evaluated by measuring characteristic curves, resolution properties and noise Wiener spectra. The potential clinical application of asymmetric screen-film systems was studied by evaluating the visibility of the anatomical structures and various types of abnormalities in comparison with those of a conventional screen-film system. The asymmetric systems showed a wider dynamic range than the conventional system. The resolution properties of asymmetric systems depend on the combination of front and back screens used. Chest radiographs obtained with asymmetric systems improved the visibility of the mediastinal area. The visibility of the lung field in the asymmetric systems was slightly inferior to that with the conventional system when the same tube potential was used. However, the image quality and visibility of various abnormalities showed greater improvement with the asymmetric systems when a lower tube potential was applied. We conclude that the selection of radiographic techniques and combination of screens are important for the clinical use of asymmetric systems.

Humans↗