Biomedical subjects

K Ito

Publications and source records attributed to K Ito.

At least 199 records · Page 11Linked to original sources

PubMed2001

Negative regulation of expression and function of Fc gamma RIII by CD3 zeta in murine NK cells.

Fc gamma RIII is involved in Ab-dependent cell-mediated cytotoxicity (ADCC) and cytokine production by NK cells. Signaling and expression of Fc gamma RIII are dependent on FcR gamma. Although NK cells express not only FcR gamma but also CD3 zeta, the role of CD3 zeta in NK cell function remains unclear. Here, we found that the expression of Fc gamma RIII on NK cells from CD3 zeta-deficient mice is unexpectedly up-regulated compared with that on cells from normal mice. Furthermore, ADCC and IFN-gamma production upon Fc gamma RIII-cross-linking by NK cells from CD3 zeta-deficient mice were also up-regulated. Up-regulation of the surface expression of Fc gamma RIII on CD3 zeta-deficient NK cells is not mediated by transcriptional augmentation of either Fc gamma RIII or FcR gamma gene because there was no significant difference in the expression of mRNA for Fc gamma RIII and FcR gamma. Transfection of CD3 zeta into a cell line expressing Fc gamma RIII and FcR gamma induced a decrease in the cell surface expression of Fc gamma RIII. These findings reveal a negative regulatory role of CD3 zeta in Fc gamma RIII-mediated function of murine NK cells.

3T3 Cells↗

PubMed2001

Narrow internal auditory meatus: an idiopathic case confirming the origin and pathway of vestibular evoked myogenic potentials in humans.

OBJECTIVE: To confirm the origin and pathway of vestibular evoked myogenic potentials (VEMPs) in humans. DESIGN: Case study. SETTING: University hospital. PATIENT: A patient with a narrow internal auditory meatus (IAM). MAIN OUTCOME MEASURES: Imaging studies and functional studies concerning the seventh and eighth cranial nerves. RESULTS: Of the 4 nerves in the IAM, all but the cochlear nerve had normal function and normal courses, despite the pronounced narrowing of the IAM. The facial nerve had a normal diameter, but the vestibular nerves were thinner. Imaging revealed that the cochlear nerve was absent or extremely thinned. Both the cochlea and the cochlear nerve showed no function in the affected ear, although the VEMPs were evoked normally. CONCLUSION: Our results definitively support the vestibular origin of VEMPs in humans.

Adult↗

PubMed2001

Inferior phrenic arteries: depiction with thin-section three-dimensional contrast-enhanced dynamic MR imaging with fat suppression.

The purpose of this study was to evaluate visibility of the inferior phrenic arteries in normal subjects at thin-section, multiphasic, three-dimensional (3D) contrast-enhanced dynamic magnetic resonance (MR) imaging with fat suppression, and to compare the appearances and frequencies of MR visualization of these vessels between normal and cirrhotic patients. This study included 95 patients (44 normal and 51 cirrhotic patients) who underwent 3D contrast-enhanced dynamic imaging on a high-performance gradient (25 mT/m) system as a part of abdominal MR examinations. The right and left inferior phrenic arteries were visible in 84% and 73% of the normal subjects, respectively. The averaged rating for visibility in the right inferior phrenic artery was significantly greater in the cirrhotic patients than in the normal subjects (2.1 +/- 0.1 vs. 1.7 +/- 0.2; P = 0.040). Mean diameters of the right inferior phrenic artery in the cirrhotic patients (1.7 +/- 0.1 mm) were significantly larger (P = 0.002) than those in the normal subjects (1.3 +/- 0.1 mm). No significant difference was noted in the mean diameters and the visibility of the left inferior phrenic artery between the two groups. The inferior phrenic arteries can frequently be identified on thin-section, 3D contrast-enhanced arterial-phase dynamic MR images with fat-suppression techniques. Dilatation of the right inferior phrenic artery depicted by this technique may be a nonspecific but an additional secondary finding suggestive of cirrhosis.

Adult↗

PubMed2001

In vitro/in vivo scaling of alprazolam metabolism by CYP3A4 and CYP3A5 in humans.

We attempted to predict the in vivo metabolic clearance of alprazolam from in vitro metabolic studies using human liver microsomes and human CYP recombinants. Good correlations were observed between the intrinsic clearance (CL(int)) for 4-hydroxylation and CYP3A4 content and between the CL(int) for alpha-hydroxylation and CYP3A5 content in ten human liver microsomal samples. Using the recombinant CYP isoforms expressed in insect cells, the CL(int) for CYP3A4 was about 2-fold higher than the CL(int) for CYP3A5 in the case of 4-hydroxylation. However, the CL(int) for CYP3A5 was about 3-fold higher than the CL(int) for CYP3A4 in the case of alpha-hydroxylation. The metabolic rates for 4- and alpha-hydroxylation increased as the added amount of cytochrome b(5) increased, and their maximum values were 3- to 4-fold higher than those without cytochrome b(5). The values of CL(int), in vivo predicted from in vitro studies using human liver microsomes and CYP3A4 and CYP3A5 recombinants were within 2.5 times of the observed value calculated from literature data. The average CL(int) value (sum of 4- and alpha-hydroxylation) obtained using three human liver microsomal samples was 4-fold higher than that obtained using three small intestinal microsomal samples from the same donors, indicating the minor contribution of intestinal metabolism to alprazolam disposition. The area under the plasma concentration-time curve (AUC) of alprazolam is reported to increase following co-administration of ketoconazole and the magnitude of the increase predicted from the in vitro K(i) values and reported pharmacokinetic parameters of ketoconazole was 2.30-2.45, which is close to the value observed in vivo (3.19). A quantitative prediction of the AUC increase by cimetidine was also successful (1.73-1.79 vs 1.58-1.64), considering the active transport of cimetidine into the liver. In conclusion, we have succeeded in carrying out an in vitro/in vivo scaling of alprazolam metabolism using human liver microsomes and human CYP3A4 and CYP3A5 recombinants.

Adult↗

PubMed2001

Activation reduction in anterior temporal cortices during repeated recognition of faces of personal acquaintances.

Repeated recognition of the face of a familiar individual is known to show semantic repetition priming effect. In this study, normal subjects were repeatedly presented faces of their colleagues, and the effect of repetition on the regional cerebral blood flow change was measured using positron emission tomography. They repeated a set of three tasks: the familiar-face detection (F) task, the facial direction discrimination (D) task, and the perceptual control (C) task. During five repetitions of the F task, familiar faces were presented six times from different views in a pseudorandom order. Activation reduction through the repetition of the F tasks was observed in the bilateral anterior (anterolateral to the polar region) temporal cortices which are suggested to be involved in the access to the long-term memory concerning people. The bilateral amygdala, the hypothalamus, and the medial frontal cortices, were constantly activated during the F tasks, and considered to be associated with the behavioral significance of the presented familiar faces. Constant activation was also observed in the bilateral occipitotemporal regions and fusiform gyri and the right medial temporal regions during perception of the faces, and in the left medial temporal regions during the facial familiarity detection task, which are consistent with the results of previous functional brain imaging studies. The results have provided further information about the functional segregation of the anterior temporal regions in face recognition and long-term memory.

Adult↗

PubMed2001

A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years.

A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

Aged↗

PubMed2001

Dynamic changes in cardiac fatty acid metabolism in the stunned human myocardium.

BACKGROUND: The chronological changes or mechanisms in cardiac fatty acid metabolism under clinical conditions of hypoxia and ischemia have not been fully elucidated. 123-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) can be used with single photon emission computed tomography (SPECT) to evaluate myocardial fatty acid metabolism. We investigated chronological changes in energy metabolism in the stunned human myocardium by means of 123I-BMIPP myocardial SPECT. METHODS AND RESULTS: We conducted 123I-BMIPP myocardial SPECT in 10 patients with stunned myocardium during the acute, subacute and chronic phases after onset. The left ventricle was divided into 9 regions on SPECT, and the degree of abnormalities in each region was scored in four grades from normal (0) to defect (4). We also examined wash-out rates on BMIPP images. The scores on early BMIPP images in the acute, subacute and chronic phases were 5.6 +/- 1.8, 13.4 +/- 3.5 and 2.5 +/- 1.1, respectively, and the score was highest in the subacute phase (p < 0.001). Similarly, scores on the late images were 2.3 +/- 1.7, 18.3 +/- 4.5 and 4.7 +/- 2.6, respectively, and highest in the subacute phase (p < 0.001). The wash-out rates (normal: 18.2 +/- 2.1%) in the acute, subacute and chronic phases were 12.1 +/- 4.8%, 44.9 +/- 10.0% and 23.1 +/- 4.6%, respectively, with the value being lowest during the acute phase (p < 0.05), and highest during the subacute phase (p < 0.001). CONCLUSION: These results suggested that fatty acid metabolism in the stunned human myocardium changes dynamically over time.

Aged↗

PubMed2001

Assessment of ampulla (Takotsubo) cardiomyopathy with coronary angiography, two-dimensional echocardiography and 99mTc-tetrofosmin myocardial single photon emission computed tomography.

UNLABELLED: We studied the causative mechanism of ampulla (Takotsubo) cardiomyopathy. METHODS: We examined 7 patients with ampulla cardiomyopathy by means of coronary angiography, two-dimensional echocardiography and 99Tc-tetrofosmin myocardial SPECT at the time of emergency admission (acute phase), at 3 to 5 days after the attack (subacute phase) and at 1 month after the attack (chronic phase). The left ventricle was divided into 9 regions on two-dimensional echocardiograms and 99mTc-tetrofosmin myocardial SPECT images, then the degree of abnormalities in each region was scored in four grades from normal (0) to severely abnormal (3). We injected nicorandil into the coronary arteries and determined the elevation in the ST segment before and after administration. RESULTS: Coronary angiography did not show stenotic lesions in any patient. The acute, subacute and chronic phase myocardial perfusion scores on 99mTc-tetrofosmin myocardial SPECT were 11.2 +/- 3.4, 2.7 +/- 2.3 and 0.4 +/- 0.5, respectively, and wall motion scores on echocardiograms were 13.0 +/- 3.6, 4.4 +/- 2.2 and 0.6 +/- 0.6, respectively, indicating improvement in all scores during the subacute phase (p < 0.01). The elevation in the ST segment (mm) on the electrocardiogram was improved from 8.3 +/- 2.7 to 4.9 +/- 1.9 after the administration of nicorandil (p < 0.05). CONCLUSION: These findings indicated that coronary microvascular spasm is one causative mechanism of ampulla cardiomyopathy.

Acute Disease↗

PubMed2001

High- and moderately high-methionine uptake demonstrated by PET in a patient with a subacute cerebral infarction.

In patients with cerebral tumors, high accumulations of L-methyl-11C-methionine (11C-Met) have been reported in some cases of cerebral ischemic disease, but no high accumulations of 11C-Met in areas where only transient arterial occlusions are most likely to occur have been reported. Herein we present a case of a high accumulation of 11C-Met in an area of frontal interhemispheric cerebral infarction and a moderately high accumulation with an unclear margin in a distant frontal convexity area. A craniotomy revealed a subacute stage of cerebral infarction in the interhemispheric lesion, and an ischemic change in the distant convexity area. Sixteen months after onset, CT scans demonstrated an infarction area in the interhemispheric lesion only, and no atrophic changes were observed in the distant convexity area indicating that no serious tissue damage had occurred.

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↗

PubMed2001

Hürthle cell tumor of the thyroid: analysis of 188 cases.

We reviewed 188 cases of Hürthle cell tumor of the thyroid (HCT) between 1982 and 1996. There were 160 women and 28 men with a mean age of 51.8 years. Thirty-one of the patients had cancer, and the others had adenoma. Age, size of the primary tumor, and preoperative thyroglobulin level were not significantly different in the cancer and adenoma patients. The gender ratio, however, was significantly different (p < 0.05). Recurrent HCT was observed in three patients with adenoma. Two patients had subcutaneous recurrence (suspected implantation), and the other patient had recurrence in the residual thyroid gland. All patients with recurrence of adenoma underwent partial lobectomy at the initial operation. Three cancer patients had recurrent disease. Locoregional recurrence was observed in one patient and distant metastases in two patients (lung in one, lung and bone in one). One of the patients with distant metastasis died from the disease, and the other is alive with the disease. Tumor implantation was observed in patients with adenoma, so intraoperative handling of the tumor requires care. It also means that this tumor, even though benign, is aggressive in terms of proliferative activity. All patients with Hürthle cell tumor should be treated by total lobectomy at least. The outcome of the cancer patients was not as poor as in previous reports.

Adenoma, Oxyphilic↗

PubMed2001

Dynamic measurement of the flow rate in cerebrospinal fluid shunts in hydrocephalic patients.

We compared clinical outcomes in hydrocephalic patients and observed variation in the rate of flow in ventriculoperitoneal shunts with changes in posture in 231 separate examinations of shunt flow in 148 patients. A small cadmium telluride detector was placed over the shunt reservoir, and clearance of radioisotope injected into the reservoir was recorded as a measure of flow. Flow rate tended to increase during head elevation. Four patterns of radioisotope clearance were seen: type I, no flow; type II, adequate flow with moderate opening pressure; type III, adequate flow with low opening pressure; and type IV, excessive flow. This categorisation reflected clinical shunt function. Our method effectively assesses flow rate with the patient in a variety of postures or during movement, yielding useful information for adjustment of shunt valve pressure.

Adolescent↗

PubMed2001

Pharmacodynamics induced by direct electric current for the treatment of 5-fluorouracil resistant tumor: an animal experiment.

The repeated use of chemotherapy to treat patients with colorectal carcinoma may be limited by the fact it creates resistance cells. However, we have observed a remarkable decrease in certain types of drug resistance in patients treated with direct electric current. Experimental studies were therefore performed in animals to determine the differences in pharmacodynamics between chemotherapy with and that without electric treatment. Tumors were created in BALB/c mice by intradermal injection of 0.25 ml 4 x 10(6) Colon 26 cells/ml in the abdomen. Seven days later the mice were divided into two groups: controls and those that underwent electric treatment. Direct electric current (1,000 V, 0.2-0.8 microA) was passed between a platinum electrode inserted intradermally and the earth during and for 1 h after a single intravenous injection of 5-fluorouracil (5-FU; 12.5 mg ml(-1) kg(-1)). Peripheral blood samples were collected before and 5, 10, 20, 30, 45, and 60 min after the injection of 5-FU. Concentrations of 5-FU in the sera and tissues were measured by HPLC. The intratumoral concentrations of 5-FU in the electric treatment group were higher than those in the controls (P<0.05, two-factor analysis of variance), but the serum concentrations were not statistically different between the two groups. Pharmacodynamic changes were thus observed as a result of electrostatic treatment during chemotherapy. This elevated 5-FU concentration in the tumor tissue is considered one of the reasons for the effective inhibition of 5-FU resistance in clinical cases.

Animals↗

PubMed2001

Fungal mastoiditis in an immunocompetent adult.

Manifest fungal infection of the middle ear, fungal mastoiditis, is a very rare entity, which is almost exclusively seen in immunocompromised patients. The authors present a case of fungal mastoiditis in a 52-year-old woman without immunocompromise. The patient presented with acutely progressing symptoms of hearing loss and dysequilibrium. Bony fistula of the semicircular canal was noted on CT scans and a marginal perforation of the tympanic membrane was also seen. Her hearing recovered following the surgery, which revealed massive granulations and proliferation of fungi but no cholesteatoma in the mastoid cavity. Fungal infection of the middle ear is rare, but can cause serious complications. The possibility should be considered even in immunocompetent patients.

Aspergillosis↗

PubMed2001

Identification of genes required for growth under ethanol stress using transposon mutagenesis in Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae exhibits high ethanol tolerance compared with other microorganisms. The mechanism of ethanol tolerance in yeast is thought to be regulated by many genes. To identify some of these genes, we screened for ethanol-sensitive S. cerevisiae strains among a collection of mutants obtained using transposon mutagenesis. Five ethanol-sensitive (ets) mutants were isolated from approximately 7,000 mutants created by transforming yeast cells with a transposon (mTn-lacZ/LEU2)-mutagenized genomic library. Although these mutants grew normally in a rich medium, they could not grow in the same medium containing 6% ethanol. Sequence analysis of the ets mutants revealed that the transposon was inserted in the coding regions of BEM2, PAT1, ROM2, VPS34 and ADA2. We constructed deletion mutants for these genes by a PCR-directed disruption method and confirmed that the disruptants, like the ets mutants, were ethanol sensitive. Thus, these five genes are indeed required for growth under ethanol stress. These mutants were also more sensitive than normal cells to Calcofluor white, a drug that affects cell wall architecture, and Zymolyase, a yeast lytic enzyme containing mainly beta-1,3- glucanase, indicating that the integrity of the cell wall plays an important role in ethanol tolerance in S. cerevisiae.

Base Sequence↗

PubMed2001

Paired tumor marker of soluble E-selectin and its ligand sialyl Lewis A in colorectal cancer.

BACKGROUND: Better diagnosis of metastatic disease has been pursued by oncologists: however, many of the tumor markers have been still controversial. Our purpose was to estimate the usefulness of soluble E-selectin and its ligand sialyl Lewis A for more accurate diagnosis as a combined tumor marker for metastases in colorectal cancer. METHODS: E-selectin and sialyl Lewis A, collected from preoperative blood, were measured of its levels in 54 patients with colorectal cancer classified according to Dukes' stage. E-selectin was assayed by enzyme-linked immunosorbent assay, whereas sialyl Lewis A was quantified by enzyme immunoassay using immunoclone kit. RESULTS: The elevation in the level of E-selectin was significantly higher in Dukes' D group than that of healthy volunteers (P < 0.001, Fisher's procedure of least significance test), Dukes' A (P = 0.01), B (P = 0.025) and C (P < 0.01). Significantly higher level of sialyl Lewis A was shown in the group of metastases than that of non-metastases (P < 0.0068. Student's t-test). Paired elevation of E-selectin and sialyl Lewis A was significantly higher in the hematogenous metastases than non-metastases (P < 0.001, Fisher exact test). CONCLUSIONS: These results suggest that E-selectin could play some role in the progress of hematogenous metastases. The elevation of E-selectin alone or both E-selectin and sialyl Lewis A may be one of the useful indexes for more precise diagnosis of hematogenous metastases of human colorectal cancer.

Adult↗

PubMed2001

Differential diagnosis of large-sized pedunculated polypoid lesions of the gallbladder by endoscopic ultrasonography: a prospective study.

PURPOSE: We have previously reported the effectiveness of endoscopic ultrasonography (EUS) for the differential diagnosis of pedunculated polypoid lesions of the gallbladder, based on retrospective studies using resected specimens. We proposed the following diagnostic criteria for EUS findings: when the contour of a lesion is nodular or smooth, the lesion is diagnosed as a neoplasm, and when a lesion has a granular contour, it is diagnosed as a nonneoplasm. The present study was designed to verify the clinical utility of our EUS ctiteria prospectively. METHODS: Forty-six consecutive patients with pedunculated polypoid lesions of the gallbladder 10mm or greater in size diagnosed as nonneoplasms at the initial EUS, all of whom underwent follow-up examinations, were enrolled in this study. The occurrence of changes in these lesions during the observation period was examined. RESULTS: No evident changes in lesions were observed in 43 of the 46 patients. Spontaneous self-detachment of lesions was recognized during the observation period in the other 3 patients. CONCLUSIONS: EUS is useful for determining treatment indications for pedunculated polypoid lesions of the gallbladder, even when the lesions are large, and contributes to avoiding unnecessary surgery.

Adenomatous Polyps↗

PubMed2001

Adenovirus-mediated transduction of Escherichia coli uracil phosphoribosyltransferase gene increases the sensitivity of esophageal cancer cells to 5-fluorouracil.

Esophageal cancer is associated with the poorest prognosis among the digestive tract cancers, and chemotherapy is the treatment of choice for many patients. In this study, we experimentally introduced an Escherichia coli-derived uracil phosphoribosyltransferase (UPRT) gene to cultured esophageal cancer cell lines to potentiate the antitumor effects of a representative anticancer drug, 5-fluorouacil (5-FU). UPRT is a pyrimidine salvage enzyme that catalyzes the synthesis of uridine monophosphate from uracil and PRPP. The UPRT gene was transduced into five cultured esophageal cancer cell lines, TE1, TE2, TE3, NUEC1, and T.T, using an adenovirus vector. It was confirmed that the sensitivities of all cultured cell lines to 5-FU were increased in vitro. Subsequently, the T.T line was subcutaneously inoculated into nude mice to induce tumors, after which 5-FU was administered intraperitoneally. When a UPRT gene-recombinant adenovirus vector was directly injected into the tumors, tumor proliferation was markedly inhibited compared with that in the group treated with 5-FU alone, suggesting potentiation of 5-FU sensitivity by UPRT gene transduction in vivo. Therefore, we potentiated the effects of commercially available anticancer drugs by gene transduction. Our method may prove useful as a new form of cancer gene therapy in the future.

Adenoviridae↗