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Biomedical subjects

I Ohashi

Publications and source records attributed to I Ohashi.

At least 19 recordsLinked to original sources
PubMed2002

MR detection of iliac bone marrow involvement by malignant lymphoma with various MR sequences including diffusion-weighted echo-planar imaging.

OBJECTIVE: To assess the diagnostic accuracy of MR imaging for detecting bone marrow infiltration by malignant lymphoma. PATIENTS AND DESIGN: Fifty-three patients with malignant lymphoma underwent MR imaging and bone marrow biopsy. In 80 iliac crests of the 53 patients (13 positive specimens in 9 patients and 67 negative specimens in 44 patients), biopsy results and the signal intensity characteristics were compared. MR sequences included T1-weighted SE, T2-weighted FSE with fat suppression, FSE STIR, and diffusion-weighted EPI with fat suppression at 1.5 T. RESULTS AND CONCLUSIONS: To detect lymphoma infiltration, T1-weighted SE had the highest sensitivity (92%) and diffusion-weighted EPI with fat suppression and FSE STIR had the highest specificity (92.5% and 92%, respectively). A combination of T1-weighted SE and FSE STIR yielded the highest sensitivity and specificity (85% and 97%, respectively). A combination of T1-weighted SE and FSE STIR sequences seems to be the current choice of imaging protocol for detecting bone marrow infiltration by malignant lymphoma.

Biopsy↗
PubMed2001

Relationship between bone marrow cellularity and apparent diffusion coefficient.

This study was performed to determine if there is a relationship between apparent diffusion coefficient (ADC) and cellularity of bone marrow of the posterior ilium. Four groups of various marrow cellularity underwent diffusion-weighted echo-planar imaging: 1) adults with normal hypocellularity (21 patients); 2) adults with normal normocellularity (13 patients); 3) young children with normal hypercellularity (5 patients); and 4) adults with lymphoma-related hypercellularity (3 patients). In all adults, marrow cellularity was confirmed by uni-or bilateral bone marrow biopsies. In children, the iliac marrow was presumed hypercellular because of their ages. A total of 66 ADC values of bone marrow calculated from diffusion-weighted images with b-values of 30 and 300 seconds/mm(2) was evaluated. Hypercellular marrow (normal and lymphoma-related) showed the highest mean ADC, and hypocellular the lowest ADC. Statistically significant differences were found between three groups of normal marrow: hypocellular, normocellular, and hypercellular. There is a positive correlation between ADC and cellularity of bone marrow. J. Magn. Reson. Imaging 2001;13:757-760.

Adult↗
PubMed2001

Functional evaluation with intravoxel incoherent motion echo-planar MRI in irradiated salivary glands: a correlative study with salivary gland scintigraphy.

The purpose of this study was to determine the relationship between the apparent diffusion coefficient (ADC) measured on intravoxel incoherent motion (IVIM) echo-planar magnetic resonance imaging (MRI) and salivary gland function. Twenty-one patients with head and neck malignancies underwent MRI and salivary gland scintigraphy before and after radiotherapy. Based on the scintigraphic results, each major salivary gland was classified into two groups (dysfunctional and functional) and ADCs measured on IVIM MRI were compared between the two groups. Furthermore, the relationship of ADC to scintigraphic parameters, maximum accumulation (MA), and the uptake ratio (UR), were analyzed. ADCs of the dysfunctional group decreased significantly after radiotherapy (P <.01), whereas those of the functional group showed no significant change. Furthermore, positive correlations were found between the ADC ratio and both MA (P <.005) and UR (P <.001). ADC measurement on IVIM echo-planar MRI is a potentially useful means of evaluating salivary gland function.

Adult↗
PubMed2001

Simple and low-cost tele-nuclear medicine conference system with the e-mail protocol.

PURPOSE: Because of the recent innovative growth in computer technology, digital imaging, and the Internet, we can take advantage of these facilities for education and clinical work in nuclear medicine. We developed a tele-nuclear medicine conference system with electronic mail (e-mail) on the Internet. METHODS: Twenty-one physicians (20 radiologists, 1 neurologist), 6 technologists and 2 medical students in six university hospitals (Japan 5, Canada 1), 5 local hospitals in Japan participated in this project. We used digital still cameras (330 k pixels) equipped with a floppy disk drive and 10 x optical zoom to digitize images with JPEG compression (640 x 480 matrix). The images were attached to e-mail messages (containing a brief description of each case). The mail was sent simultaneously to all members on the mailing list. Scintigram and SPECT images as well as other radiological images were sent by e-mail. Reply mails about each case were sent to all members via the mailing list. RESULTS: During a period of 6 months, 18 cases (tumor/infection: 7, bone: 6, cardiovascular: 1, neurology; 3, endocrine: 1) with 144 e-mails (average 5.6/case) were submitted to the conference. The average period of discussion was 15.6 days. The number of attached images was 1 to 9 (average, 4.2/e-mails). JPEG compression rate was 1/10 to 1/20. The quality of the images was good enough for discussion. Some cases required additional images for further discussion. CONCLUSION: Our tele-nuclear medicine conference with an electronic mailing list and digital camera was simple and low-cost. The conference system was useful for education and clinical work.

Canada↗
PubMed2000

Anisotropic diffusion in kidney: apparent diffusion coefficient measurements for clinical use.

The purpose of this study was to evaluate anisotropy of the kidney by measurements of the apparent diffusion coefficient (ADC) using commercially available magnetic resonance (MR) imaging. Fifty-one consecutive patients underwent diffusion-weighted echoplanar MR imaging of the upper abdomen with five different strengths of motion probing gradients (b = 1.51, 55.3, 36.6, 317, and 932 sec/mm2) applied along the z-axis. Four ADC values for the upper pole and central portion of the kidney were calculated from four different b-value ranges and compared. The ADCs for the kidney calculated in the lower b-value ranges were significantly higher than those in the higher ranges. The ADCs for the upper pole portion were significantly higher than those for the central portion except for one in the highest b-value range. Diffusion in the kidney is anisotropic, probably due to the kidney's radially oriented structures such as renal vessels and tubules.

Anisotropy↗
PubMed1998

Human slow cortical potential in association with voluntary jaw movements.

The distribution of a readiness potential (RP), i.e., a negative-going slow cortical potential (SCP) preceding the onset of voluntary movements, was studied in association with self-paced voluntary jaw-closing and jaw-opening movements in 4 healthy human subjects. A negative-going SCP starting at ca.1.5-2.0 s preceding the onset of the self-paced jaw-opening and jaw-closing movements was found at all the recorded sites of Fz, Cz, Pz, F3, F4, F7, F8, C3, C4, T3 and T4. The RP was maximum in amplitude at Cz (ca.8microV), although there was no significant difference between Cz and either C3 or C4; it was smaller at T3 and T4 than at any of Fz, Cz, Pz, C3, and C4. The polarity, amplitude, and time course of the RP in association with jaw movements was virtually the same as those associated with voluntary unilateral extension of the middle finger, except for a contralaterally-dominant side asymmetry between C3 and C4 in the latter. There was neither rapidly increasing negative potential (NS') in the RP recorded from any site, nor bilateral difference in the RPs coinciding with unilateral biting of a gauze pad. It is suggested that the motor cortex would be activated bilaterally in coordination even in the case of unilateral biting.

Adult↗
PubMed1996

Localization of unique functional determinants in the calmodulin lobes to individual EF hands.

We have investigated the functional interchangeability of EF hands I and III or II and IV, which occupy structurally analogous positions in the native I-II and III-IV EF hand pairs of calmodulin. Our approach was to functionally characterize four engineered proteins, made by replacing in turn each EF hand in one pair by a duplicate of its structural analog in the other. In this way functional determinants we define as unique were localized to the component EF hands in each pair. Replacement of EF hand I by III reduces calmodulin-dependent activation of cerebellar nitric oxide synthase activity by 50%. Replacement of EF hand IV by II reduces by 60% activation of skeletal muscle myosin light chain kinase activity. There appear to be no major unique determinants for activation of these enzyme activities in the other EF hands. Replacement of EF hand III by I or IV by II reduces by 50-80% activation of smooth muscle myosin light chain kinase activity, and replacement of EF hand I by III or II by IV reduces by 90% activation of this enzyme activity. Thus, calmodulin-dependent activation of each of the enzyme activities examined, even the closely related kinases, is dependent upon a distinct pattern of unique determinants in the four EF hands of calmodulin. All the engineered proteins examined bind four Ca2+ ions with high affinity. Comparison of the Ca2+-binding properties of native and engineered CaMs indicates that the Ca2+-binding affinity of an engineered I-IV EF hand pair and a native I-II pair are similar, but an engineered III-II EF hand pair is intermediate in affinity to the native III-IV and I-II pairs, minimally suggesting that EF hands I and III contain unique determinants for the formation and function of EF hand pairs. The residues directly coordinating Ca2+ ion appear to play little or no role in establishing the different Ca2+-binding properties of the EF hand pairs in calmodulin.

Amino Acid Sequence↗
PubMed1996

Isoflurane preserves adenosine triphosphate levels in anoxic isolated rat hepatocytes by stimulating glycolytic adenosine triphosphate formation.

The hypothesis that general anesthetics protect energy reserves by decreasing energy demand is widely accepted but poorly substantiated. Isoflurane at clinical doses preserved adenosine triphosphate (ATP) levels in anoxic isolated hepatocytes. Specific inhibitors were used to block mitochondrial and/or glycolytic ATP formation to ascertain whether pathways of energy supply or demand, or both, were involved in ATP preservation by isoflurane. Hepatocytes were isolated from fed adult male rats after perfusing livers with Krebs buffer containing collagenase. Cells were incubated in Krebs buffer for 0-30 min at 25 degrees C under N2/CO2 (95%/5%) +/- isoflurane 0.63 mM in liquid phase. Oligomycin, iodoacetate, or fasting were used to block mitochondrial and glycolytic ATP formation. Under anoxia alone, ATP levels declined more slowly in the presence than in the absence of isoflurane, confirming the ATP-protective effect of isoflurane reported previously. With oligomycin plus iodoacetate blocking all ATP formation, ATP decline (representing pure ATP consumption) was not slowed by isoflurane. Isoflurane's protective effect recurred when glycolytic ATP supply was restored by incubating with oligomycin only. The protective effect was accompanied by increased lactate accumulation, and both effects-ATP preservation and lactate formation-were similarly dependent on isoflurane concentration. We conclude that the protective effect of isoflurane on energy status in anoxic isolated hepatocytes was not associated with reduced ATP demand but with enhanced ATP supply via stimulation of glycolysis.

Adenosine Triphosphate↗
PubMed1996

Segmental anatomy of the liver under the right diaphragmatic dome: evaluation with axial CT.

PURPOSE: To evaluate the segmental anatomy of the liver under the right side of the diaphragm with axial computed tomography (CT). MATERIALS AND METHODS: Forty-six patients underwent CT arteriography with selective catheterization of the right hepatic artery in 25 cases, the left hepatic artery in 12, the anterior branch of the right hepatic artery in six, the posterior branch of the right hepatic artery in five, the superior anterior branch of the right hepatic artery in 10, and the superior posterior branch of the right hepatic artery in eight. RESULTS: The boundary between the right and left lobes shifted by 16.2 degrees +/- 16.8 anteriorly, and the boundary between the anterior and posterior segments shifted by 43.9 degrees +/- 14.0 posteriorly to the line through the middle or right hepatic vein from the inferior vena cava. The top of the liver consisted of both lobes in 22 patients, only the right lobe in 17, and only the left lobe in two. Participation of segment 7 in the top was not demonstrated. CONCLUSION: The line that extends beyond the middle or right hepatic vein from the inferior vena cava does not coincide with the main or right longitudinal scissura on axial images of the upper portion of the liver.

Angiography↗
PubMed1996

[Effects of craniofacial pain on jaw jerk in man].

Jaw jerk was evoked in 12 normal subjects (N group) and 12 patients with unilateral craniofacial pain who had neither mandibular deviation nor organic changes in the temporomandibular joint (P group), about every ca. 2 sec by tapping the center of the chin with a reflex hammer, in which a microswitch was embedded to indicate the time of its contact with the chin. The surface electromyogram of the masseter muscle was recorded bilaterally. It was found that (1) in the N group, there was no difference in the onset latency between the right (6.30 +/- 1.06 ms; n = 192) and left (6.32 +/- 1.04 ms; n = 192) sides (P > 0.05); (2) in the P group, the latency was shorter on the painful side than on the pain-free side; and (3) after pain was relieved by treatment, the bilateral difference in the latency of jaw jerk disappeared, and the latencies fell to that in normal subjects. It was concluded that the bilateral difference of the latency of jaw jerk can be used as an investigative criterion for the existence of pain.

Electromyography↗
PubMed1995

Inhibitory effect of a synthetic protease inhibitor (gabexate mesilate) on the respiratory burst oxidase in human neutrophils.

We investigated the mechanism by which the synthetic protease inhibitor gabexate mesilate inhibits the production of the superoxide anion by human neutrophils. We found that gabexate mesilate suppressed SOD-inhibitable cytochrome c reduction in a dose-dependent manner in intact neutrophils activated with phorbol ester. Gabexate mesilate slightly scavenged the superoxide anion in the pyrogallol assay. The reagent also inhibited superoxide anion production in a dose-dependent manner in a cell-free oxidase-activating system. Translocation of the cytosolic respiratory burst oxidase components, the 47- and 65-kDa proteins, to membranes was suppressed by the reagent in intact cells stimulated with phorbol ester. Gabexate mesilate also reduced arachidonic acid-induced translocation of the components to the membrane fraction in the cell-free system. These results demonstrate that gabexate mesilate suppresses superoxide anion production by reducing the translocation of the 47- and 65-kDa proteins to the plasma membrane.

Cell Membrane↗
PubMed1995

Hepatic pseudolesion in the left lobe around the falciform ligament at helical CT.

PURPOSE: To determine the prevalence and possible cause of pseudolesions in the left hepatic lobe around the falciform ligament at hepatic helical computed tomography (CT). MATERIALS AND METHODS: Portal venous-dominant CT scans of 472 consecutive patients were reviewed. CT of the left hepatic lobe was performed after injection of contrast material into the portal vein in 73 patients, the hepatic artery in 32, and the internal thoracic artery in four. The scans were compared with those obtained at helical CT, and the findings were analyzed. RESULTS: Pseudolesions were seen on 64 (14%) of 472 helical CT scans and correlated well (accuracy, 96%) with portal perfusion defects. They were not more enhanced than the surrounding liver parenchyma at CT arteriography with hepatic artery injection but were enhanced in two patients at CT arteriography with internal thoracic artery injection. CONCLUSION: Pseudolesions are caused by portal perfusion defects and may receive an aberrant blood supply.

Adolescent↗
PubMed1995

Hepatic hemangioma: findings with two-phase CT.

PURPOSE: To characterize the appearance of hemagiomas at two-phase dynamic incremental computed tomography (CT) and to determine the cause of contrast material enhancement of adjacent parenchyma in the first series. MATERIALS AND METHODS: Contrast-enhanced CT images of 51 hemangiomas in 20 patients were reviewed. Enhancement patterns of hemangiomas in the first series were classified as homogeneous high, peripheral high, and low attenuation; in the second series, as homogeneous high, peripheral high, iso-, and low attenuation. Correlations between arterioportal shunts and early parenchymal enhancement were evaluated in 45 hemangiomas in the 17 patients who underwent angiography. RESULTS: Thirty-two hemangiomas progressively became enhanced. Four had low and eight had homogeneous high attenuation in both series. Seven changed from homogeneous high to isoattenuation. Early parenchymal enhancement was well correlated with presence of arterioportal shunt. CONCLUSION: Low-attenuation hemangiomas and those that changed from homogeneous high to isoattenuation are atypical and difficult to differentiate from other neoplasms. Most early parenchymal enhancement is caused by associated arterioportal shunts.

Angiography↗
PubMed1995

Changes in serum granulocyte colony-stimulating factor (G-CSF) and interleukin 6 (IL-6) after surgical intervention.

To evaluate the physiological role of G-CSF following surgery, we measured the serum levels of immunoreactive IL-6 and G-CSF sequentially in nine patients after major elective thoracoabdominal surgery for esophageal carcinoma. Both G-CSF and IL-6 levels reached their maxima at the first postoperative day and decreased thereafter. There was a significant correlation between serum G-CSF (y) and IL-6 (x) levels (y = 3.273x + 3.991; r = 0.787, n = 78, p < 0.001). In the case that developed aspiration pneumonia and ARDS at the second postoperative day, the measured G-CSF level was less than half the predicted value. The relationship between serum G-CSF and IL-6 levels supports the central role of G-CSF as the host defense response modifier and, thus, low G-CSF levels in the circulation is one reason for the immunodeficient state after major surgery.

Aged↗
PubMed1994

Effect of granulocyte-macrophage colony-stimulating factor on sepsis-induced organ injury in rats.

The administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) to patients with severe active infections has been questioned because activation of neutrophils may cause tissue injury. To identify the effect of GM-CSF administration on severe sepsis, we examined the survival rate and pathologic changes in vital organs using the rat lethal sepsis model. Rats received 20 micrograms of recombinant murine GM-CSF (rmGM-CSF) 3 hours after the onset of peritonitis induced by cecal ligation and puncture. After 48 hours, the survival rate did not improve, and earlier deaths than in the control group were observed. In addition, the inhibition of early leuko-sequestration in the peritoneal cavity was seen in animals treated with GM-CSF. These results suggested that the administration of rmGM-CSF after the onset of sepsis was not beneficial; thus, we concluded that care should be taken in the clinical use of GM-CSF in severe infection.

Animals↗
PubMed1994

The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy.

BACKGROUND: Male patients with oral and oropharyngeal cancer are known to have high risk of concomitant esophageal cancer developing. Thus, mass screening programs are pursued to detect such esophageal cancer early, and in a mass screening trial of patients with early oral and oropharyngeal cancer, the efficacy of Lugol dye endoscopy for detecting concomitant esophageal cancers has been evaluated. METHODS: Lugol dye was used in an endoscopic screening of 101 patients with oral cancer and 26 with oropharyngeal cancer; all of the patients were men. RESULTS: Among these 127 patients, eight (6.3%) clinical asymptomatic concomitant esophageal cancers were detected, and four of these eight cancers were found in the patients with oropharyngeal cancer. Five of these eight superficial lesions could not be detected by ordinary endoscopy or barium study. CONCLUSION: Our results show that Lugol dye endoscopy is indispensable for monitoring male patients with oral or oropharyngeal cancer to detect an early concomitant esophageal cancer. In addition, a higher frequency of concomitant esophageal cancer was seen in the patients with oropharyngeal cancer than in the patients with oral cancer.

Adult↗
PubMed1994

The prognostic significance of surgical margin in liver resection of patients with hepatocellular carcinoma.

OBJECTIVE: To evaluate the prognostic significance of surgical margin in liver resection of patients with hepatocellular carcinoma. DESIGN: Retrospective study. SETTING: The Center for Adult Diseases, Osaka, Japan, between 1980 and 1989. PATIENTS: One hundred eighty-five patients with hepatocellular carcinoma who underwent liver resection with complete extirpation. MAIN OUTCOME MEASURE: Cumulative survival rate. RESULTS: The patients were divided into a wide surgical margin group, in which the lesion was excised with a margin of 1.0 cm or more, and a narrow surgical margin group, in which the margin was less than 1.0 cm. No significant differences could be detected in survival rates for 3 years or longer. Mean +/- SE tumor sizes were 3.4 +/- 0.4 cm and 4.4 +/- 0.3 cm, respectively, in the wide and narrow surgical margin groups. The patients were divided into three groups according to tumor size: group 1, 2.0 cm or less in diameter; group 2, greater than 2.0 cm but 5.0 cm or less in diameter; and group 3, greater than 5.0 cm in diameter. In groups 2 and 3, no significant differences in survival rates were found between the wide and narrow surgical margin groups. In group 1, the survival rate was significantly higher in the wide surgical margin group than in the narrow surgical margin group (P < .05). CONCLUSIONS: Small hepatocellular carcinomas of 2.0 cm or less in diameter should be resected with an adequate surgical margin. However, surgical margin was not a significant factor in the resection of hepatocellular carcinomas larger than 2.0 cm.

Adult↗