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M Ohkawa

Publications and source records attributed to M Ohkawa.

At least 19 recordsLinked to original sources
PubMed2000

Colocalization of GP125/CD98 with tropomyosin isoforms at the cell-cell adhesion boundary.

Two monoclonal antibodies designated as 1F6 and 4B10 were obtained on screening for reactivities to CD98-associated molecules by sandwich-type enzyme-linked immunosorbent assaying using hybridoma culture supernatants as the solid phase, cell lysates as an antigen source, and a mixture of biotinylated antibodies to CD98HC as a detector. Flow cytometric analysis with microspheres in combination with 1F6, 4B10, and anti-CD98HC also indicated the association of antibody-defined antigen(s) with CD98. 1F6 and 4B10, stained fibrillate components in fixed and permeated cells but were not reactive with unfixed live cells, suggesting that epitopes reside in the cytoskeleton-associated structure in the intracellular region. Two-color immunostaining followed by confocal microscopy revealed the colocalization of the antigen with CD98 at the cell-cell adhesion boundary of HeLa cells. 1F6 detected proteins with relative molecular masses of 33,000 to 43,000 on immunoblotting analysis involving cell lysates of human and rat cell lines. Analysis with a purified tropomyosin specimen from rabbit skeletal muscle demonstrated that 1F6 and 4B10 recognize tropomyosin. Two-dimensional gel electrophoresis followed by immunoblotting analysis revealed that 1F6 recognizes various tropomyosin isoforms. These results indicated that CD98 physically associates directly or indirectly with tropomyosin, and that this association is closely related to the cell-cell interaction.

Actins↗
PubMed2000

Comparative evaluation of Tc-99m MIBI and Tl-201 chloride SPECT in non-small-cell lung cancer mediastinal lymph node metastases.

PURPOSE: To compare the utility of Tc-99m MIBI SPECT and Tl-201 chloride SPECT for presurgical assessment of lung cancer mediastinal lymph node metastases. METHODS: Forty-one patients with non-small-cell lung cancer underwent dual-isotope imaging with Tl-201 chloride and Tc-99m MIBI and were evaluated for mediastinal lymph node involvement. RESULTS: The sensitivity rates of early and delayed Tc-99m MIBI SPECT and of early and delayed Tl-201 chloride SPECT for detecting mediastinal nodal metastases were 69%, 69%, 92%, and 92%, respectively. The corresponding specificity rates were 96%, 96%, 93%, and 96%. CONCLUSION: Tl-201 chloride SPECT is superior to Tc-99m MIBI SPECT when used to detect mediastinal lymph node metastases in patients with non-small-cell lung cancer.

Adult↗
PubMed2000

Diagnostic value of TI-201 and three-phase bone scintigraphy for bone and soft-tissue tumors.

PURPOSE: Although TI-201 is highly sensitive for detecting bone and soft-tissue tumors, its uptake is not specific for malignant lesions. This study assessed the differentiation of malignant and benign lesions and evaluated the sensitivity, specificity, and accuracy of TI-201 imaging and three-phase bone scans. MATERIALS AND METHODS: Forty bone and soft-tissue tumors (16 malignant and 24 benign) were evaluated. TI-201 static images were acquired 10 minutes (early) and 2 hours (delayed) after injection of the radionuclide. Within 14 days, three-phase bone scintigraphy was performed using Tc-99m HMDP with the patient in the same position. The count ratio of the lesion compared with the normal contralateral or adjacent site (L:N ratio) was measured. RESULTS: With TI-201 scintigraphy, mean (+/- SD) values of early and delayed L:N ratios were 3.36 +/- 1.25 and 2.88 +/- 1.20, respectively, in malignant lesions; and 1.88 +/- 1.14 and 1.48 +/- 0.76, respectively, in benign lesions. TI-201 accumulation in benign lesions was significantly less than that of malignancies on early and delayed images. However, an overlap of both ratios between malignant and benign lesions was seen. No such significance was detected on three-phase bone scintigraphy (L:N ratios of malignant and benign tumors were 2.57 +/- 1.22 and 2.24 +/- 2.11, respectively, for blood flow imaging; 2.41 +/- 0.78 and 2.26 +/- 1.54, respectively, for blood pool imaging; and 2.80 +/- 2.10 and 2.89 +/- 4.55, respectively, for bone imaging). When we assumed that the tumor was malignant when the delayed TI-201 L:N ratio exceeded the blood pool phase L:N ratio with bone scintigraphy, the sensitivity rate was 81%, specificity rate was 100%, and accuracy rate was 93%. CONCLUSIONS: TI-201 imaging for bone and soft-tissue tumors was better than three-phase bone scintigraphy alone but was not good enough to clearly differentiate malignant lesions from benign ones. TI-201 scintigraphy, performed in combination with three-phase bone scintigraphy, may be superior to either one of the two imaging procedures alone for bone and soft-tissue tumor diagnosis.

Adolescent↗
PubMed2000

Effect of olprinone, phosphodiesterase III inhibitor, on cerebral blood flow assessed with technetium-99m-ECD SPECT.

Few clinical reports exist regarding the effects of phosphodiesterase III inhibitors on cerebral arteries. Therefore we used a [99mTc]-ECD brain SPECT and an ultrasound method to quantitatively evaluate cerebral and systemic flow dynamics after the administration of olprinone, a phosphodiesterase III inhibitor. In 15 patients (65 +/- 8 years, M/F = 13/2) with no abnormalities on a brain computed tomography (CT), cerebral blood flow and cardiac output were measured using [99mTc]-ECD brain SPECT and Doppler echocardiography, respectively. Measurements were repeated at baseline and after the administration of olprinone. Significant increases in cerebral blood flow (p = 0.0007) and cardiac output (p = 0.001) were observed, and systolic blood pressure (p = 0.02) and systemic vascular resistance (p = 0.002) significantly decreased. No significant correlation between the increase in cerebral blood flow and the increase in cardiac output was observed. The data indicate that olprinone has a direct vasodilator effect on the cerebral artery, which was little related to the increase in cardiac output in patients who had not experienced stroke.

Aged↗
PubMed2000

Visualization of the motor activation area using SPECT in neurosurgical patients with lesions near the central sulcus.

UNLABELLED: The purpose of this study was to visualize the motor area related to finger movement and a fist-making task using SPECT in patients with lesions near the central sulcus. METHODS: Eleven patients (9 with a brain tumor, 1 with cerebral infarction, and 1 with an arteriovenous malformation) were investigated. The first intravenous injection of 99mTc-ethyl cysteinate dimer (ECD) for the motor activation SPECT images was administered 2 min after completion of the fist-making task with the hand contralateral to the brain lesion. The movement was stopped 2 min after injection, and activation SPECT was performed. After the scan, the second dose of 99mTc-ECD was injected into resting patients, and a second set of SPECT images was acquired. The first set of images was subtracted from the second set to obtain control images. Regions of interest were set bilaterally on the sensorimotor hand area; the supplementary motor area; the frontal, temporal, and occipital lobes; and the cerebellar hemispheres. The results of activation SPECT were expressed as positive or negative for a high-count area, and the regional percentage change for activation images relative to resting images was calculated. RESULTS: Visual assessment of activation images was positive in 9 patients for the sensorimotor hand area and 7 patients for the supplementary motor area. The regional percentage change between activation and resting images for the high-count areas was 19.7% for the sensorimotor hand area and 18.2% for the supplementary motor area. Both values were significantly higher than those for other areas (P<0.05). CONCLUSION: Motor activation SPECT using a 99mTc-ECD split-dose method is easy to perform and may be helpful for presurgical visualization and identification of the sensorimotor hand area or the supplementary motor area.

Brain Mapping↗
PubMed1999

Re-evaluation of sexual dimorphism in human corpus callosum.

To study the sexual dimorphism of human corpus cauosum (CC), we analyzed the midsaggital magnetic resonance imaging (MRI) morphometry in 67 adults aged (mean+/-s.d.) 36.82+/-9.35 years. Four specific angles of the CC were determined. All four angles in 34 females and 33 age-matched males showed a significant difference between females and males. These morphometric findings confirm a gender difference in the orientation of corpus callosum.

Adult↗
PubMed1999

Accumulation of technetium-99m pertechnetate in a patient with metastases of thyroid carcinoma.

Accumulation of both Tc-99m pertechnetate and radioiodine upon scintigraphy in thyroid carcinoma and/or in its metastases is a rare occurrence. In this paper we describe a patient who was taken to surgery for left lobectomy of the thyroid with follicular adenocarcinoma and who had accumulation of both I-131 and Tc-99m pertechnetate in lung metastases. The accumulation of I-131 was less than that of Tc-99m pertechnetate. The use of Tc-99m pertechnetate for imaging for diagnosis of functioning thyroid metastases is discussed.

Adenocarcinoma, Follicular↗
PubMed1999

Tc-99m Technegas scintigraphy to evaluate the lung ventilation in patients with oral corticosteroid-dependent bronchial asthma.

Bronchial asthma is a clinical syndrome characterized by the reversibility of airway obstruction. Recently it has been suggested that remodeling of the airway causes irreversible airway obstruction which may be responsible for the patient's symptoms. With this background, the purpose of the present study was to assess patients with corticosteroid-dependent asthma by Tc-99m Technegas scintigraphy (Technegas) in both planar and SPECT images. Twelve patients (7 females and 5 males aged 36-72 years with a median age of 60 years: 4 smokers and 8 non-smokers) with oral corticosteroid-dependent asthma were enrolled in this study. Lung ventilation scanning with Technegas in both planar and SPECT images, high-resolution computed tomography, and pulmonary function tests were performed in all patients. The results of Technegas scanning were graded and correlations with other clinical parameters were evaluated. Significant abnormalities were detected by ventilation scintigraphy with Technegas in patients with corticosteroid-dependent bronchial asthma even during remission. Our data demonstrate that airflow obstruction took place in patients with corticosteroid-dependent asthma even during remission. Technegas scanning appears to be a useful radiopharmaceutical for demonstrating airflow obstruction in patients with bronchial asthma.

Adrenal Cortex Hormones↗
PubMed1999

Visualization of esophageal non-Hodgkin's lymphoma with Ga-67 scintigraphy.

Although non-Hodgkin's lymphoma of the gastrointestinal tract is common, primary esophageal lymphomas represent less than 1% of all gastrointestinal tumors. We report a case of primary non-Hodgkin's lymphoma of the esophagus. Ga-67 scintigraphy showed characteristic intense accumulation in the esophageal wall. The histopathology belonged to the category of mucosa-associated lymphoid tissue lymphoma.

Citrates↗
PubMed1999

Glutathione depletion causes an uncoupling effect on retinal horizontal cells through oxidative stress.

To investigate a physiological role of glutathione in the horizontal cells of carp retina, the gap junctional intercellular communication between horizontal cells was studied using the techniques of intracellular recording of light-induced responses and coupling of the fluorescence dye Lucifer Yellow. Intravitreal injection of 2.5 micromol L-buthionine sulfoximine, an inhibitor of glutathione synthesis, induced a dramatic reduction (20% of control) of retinal glutathione level two days after treatment. The low level of glutathione continued for a further four to five days, and thereafter gradually recovered to about 40% (20 days after injection) and 70% (50 days after injection) of the control level. The spatial properties of the photopic L-type horizontal cell response were examined by enlarging the diameter of the central spot and peripheral annulus over the recording point. In normal retinas, the response amplitude of horizontal cells was monotonically enhanced as the diameter of the spot increased (0.5-4.0 mm) and correspondingly the dye diffusion area was wide, as the injected Lucifer Yellow normally diffused to several neighboring cells. Treatment with L-buthionine sulfoximine significantly altered the spatial properties of horizontal cells by increasing the response amplitude to central spots and slightly decreasing that to peripheral annuli, which were observed by four days after injection. It also restricted intracellular Lucifer Yellow to one or two cells. Accompanying the recovery of the cellular level of glutathione, the spatial properties and dye coupling of horizontal cells were restored to normal. A time lag (two days) of initiation in retinal glutathione depletion and alteration of spatial or dye coupling properties of horizontal cells is discussed, together with reactive oxygen species accumulation.

Animals↗
PubMed1999

Fast and slow recovery phases of goldfish behavior after transection of the optic nerve revealed by a computer image processing system.

As the goldfish is a common experimental animal for vision research, including psychophysical behavior, it is very important to quantitatively score fish behavior. We have previously developed a computer image processing system which can acquire the positional coordinates of goldfish moving freely in an aquarium and determine turning directions (go straight, right or left turn). In the present study, an algorithm to determine tilting angles of moving goldfish was constructed. We also made histograms for quantifying the interaction between pairs of goldfish (two-point distance). By using these histograms, we estimated the time-course of behavioral regeneration after optic nerve transection in goldfish. Control goldfish showed an equal percentage of right or left turns and maintained an upright position in a dorsoventral axis. When the optic nerve of a goldfish was unilaterally sectioned, the goldfish showed predominant turning and slight tilting toward the intact eye. The abnormal turning and tilting behaviors lasted for 10-14 days and then gradually decreased, returning to control behaviors by one month after the unilateral transection. When the optic nerve of a single goldfish was bilaterally sectioned, it did not show any preferential turning and tilting behavior, which is similar to what was observed in control goldfish. However, the trace maps showed that, after bilateral sectioning, fish preferred to cross the center of the tank, which was unlike control fish. In control pairs, one goldfish chased the other with a fixed small range of two-point distances. However, in pairs of goldfish with bilateral transection of the optic nerve, the blind goldfish behaved independently of each other, with a long two-point distance. The long two-point distance of the blind goldfish lasted for at least two months and then slowly returned to control two-point distance by four months after bilateral transection. Such fast and slow recovery in goldfish behaviors evoked after unilateral and bilateral transection of the optic nerve is discussed with respect to reconnection of regenerating optic nerves in the fish central nervous system. This computer image processing system is a useful tool with which we can quickly and easily quantify fish behavior.

Algorithms↗
PubMed1999

Assessment of hepatic functional reserve in cirrhotic patients by computed tomography of the caudate lobe.

In order to investigate whether the size of the caudate lobe of the cirrhotic liver is related to the hepatic functional reserve, the morphometric analysis of the caudate lobe was preformed retrospectively using computed tomography in 106 consecutive patients of whom 67 had compensated (group 1), and 39 uncompensated (group 2) liver cirrhosis. In 51 patients, hepatic measurements were repeated in follow-up. Age- and gender-matched controls were studied. The size of the caudate lobe and the ratio of the caudate to right lobe were correlated with liver function. The caudate lobe was larger in the study patients than in the controls, and larger in group 1 than in group 2 (P<0.01). The caudate to right lobe ratios were also greater in the study patients especially in group 1 (P<0.01). In follow-up, the regression coefficient for the caudate to right lobe ratio was positive in group 1 and negative in group 2 (P<0.05). Even though the caudate lobe of patients with uncompensated liver cirrhosis was larger than that of the controls, patients with compensated liver cirrhosis had a larger caudate lobe and higher caudate to right lobe ratio compared to the patients with uncompensated liver cirrhosis. The caudate lobe may have played an important role in maintaining proper liver function in these patients.

Chronic Disease↗
PubMed1999

Recurrence factors for chronic subdural hematomas after burr-hole craniostomy and closed system drainage.

Recurrence of chronic subdural hematoma after burr-hole craniostomy and closed system drainage is not uncommon. We sought to identify risk factors for recurrence. In 121 patients, various factors including age, initial neurologic status, hematoma thickness, computed tomographic density of the hematoma, midline shift, multiplicity, systemic disease, and drainage volume were compared retrospectively between nonrecurring cases and recurring cases. Recurrence was noted in 10 cases (8.3%). In recurring cases, the drainage volume was significantly larger than in nonrecurring cases, and the recurrence rate increased in proportion to drainage volume. Other factors significantly influencing recurrence were hematoma thickness and associated diabetes mellitus. Drainage contents mainly derived from either exudate within the subdural membrane or cerebrospinal fluid leakage. Entry of cerebrospinal fluid into the hematoma cavity or continuing leakage of serum components through opened endothelial gap junctions are considered to be major causes of increased drainage volume, leading in turn to recurrence of the hematoma.

Adult↗
PubMed1999

Differentiation of small solitary pulmonary nodules using Tc-99m MIBI and Tl-201 SPECT

The authors evaluated the ability of dual SPECT with Tc-99m MIBI and Tl-201 chloride to differentiate malignant and benign solitary pulmonary nodules smaller than 3 cm in diameter. Forty-three patients had solitary pulmonary nodules smaller than 3 cm in diameter based on the findings of chest CT. All patients underwent dual-isotope SPECT with Tc-99m MIBI and Tl-201 chloride. Regions of interest were placed over the tumors (T) and contralateral normal lung tissue (N) on one coronal SPECT view, and T:N ratios and retention indices were calculated. The sensitivities of early and delayed Tc-99m MIBI SPECT and early and delayed Tl-201 chloride SPECT for differentiating malignant and benign lesions were 44%, 48%, 56%, and 52%, respectively. The corresponding specificity rates were 44%, 56%, 25%, and 31%, respectively, and corresponding accuracy rates were 44%, 51%, 44%, and 44%, respectively. There were no statistically significant differences between malignant and benign lesions in the early and delayed T:N ratios for Tc-99m MIBI and Tl-201 chloride and the retention index for Tc-99m MIBI. However, the retention index using Tl-201 chloride in malignant lesions was significantly higher (P < 0.01) than that in benign lesions. Analysis of semiquantitative parameters of the T:N ratio and retention index from Tc-99m MIBI SPECT appears to have little or no value for differentiating malignant from benign solitary pulmonary nodules smaller than 3 cm in diameter. However, the retention index using Tl-201 chloride seems to be a better parameter for differentiating between these malignant and benign lesions.

Journal Article↗
PubMed1999

[A case report of urinary tract infection and meningitis caused by methicillin-resistant Staphylococcus aureus (MRSA) after transurethral resection of the prostate].

We present a case of meningitis that developed following a urinary tract infection caused by methicillin-resistant Staphylococcus aureus (MRSA) after transurethral resection of the prostate. The patient, a 69-year-old man with diabetes mellitis, underwent transurethral resection of the prostate following a diagnosis of benign prostatic hypertrophy. On the 4 th day after surgery, high fever occurred immediately after the removal of the indwelling urethral catheter. Cultures of urine and blood revealed MRSA. On the 6 th day after surgery, severe lumbago was evident and MRSA was isolated from cerebrospinal fluid. Separate administration of arbekacin or vancomycin, to which the isolated MRSA was sensitive, was not effective. Combined therapy with fosfomycin, vancomycin and human immunoglobulin effectively relieved the inflammation. Although it is generally reported that the pathogenicity of MRSA is low in the urinary tract, this case suggests that a urinary tract infection caused by MRSA can advance to sepsis and meningitis.

Aged↗
PubMed1999

[Quantitative study of 99mTc-Technegas SPECT for ventilatory impairment in pulmonary emphysema].

99mTc-Technegas scintigraphy is used to evaluate ventilation abnormalities in patients with pulmonary emphysema. Although abnormalities of ventilation distribution are easy to find, no objective index exits. Evaluation is subjective and differs with each radiologist. Thus, it is difficult to compare cases and the clinical course in the same case. The present study for quantitative evaluation demonstrated an excellent correlations between mean voxel values of the lung and stage classification. Furthermore, a correlation was observed between the mean and FEV1.0%. These findings indicate that the quantitative analysis of SPECT data is useful for classifying clinical stage and comparing cases.

Humans↗