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Biomedical subjects

Y Okajima

Publications and source records attributed to Y Okajima.

At least 37 records · Page 2Linked to original sources
PubMed1998

Decreased nitric oxide-mediated natural killer cell activation in chronic fatigue syndrome.

BACKGROUND: L-Arginine (L-Arg), one of the essential amino acids, has been reported to have an immunomodulatory effect. The precise mechanism of the L-Arg-induced natural killer (NK) cell activation remains unresolved,and the effect of L-Arg on NK cells in chronic fatigue syndrome (CFS) patients has not been estimated. METHODS: NK cell function was evaluated in 20 subjects with CFS and compared with that in 21 healthy individuals. RESULTS: In healthy control subjects, NK activity was significantly increased after treatment with L-Arg, an NK function enhancer, for 24 h, whereas the same treatment failed to enhance NK activity in the CFS patients. We thus focused on L-Arg metabolism, which involves nitric oxide (NO) production through NO synthase (NOS). The expression of inducible NO synthase (iNOS) transcripts in peripheral blood mononuclear cells was not significantly different between healthy control subjects and CFS patients. The L-Arg-mediated NK cell activation was abolished by addition of NG-monomethyl-L-arginine, an inhibitor for iNOS. Furthermore, incubation with S-nitroso-N-acetyl-penicillamine, an NO donor, stimulated NK activity in healthy control subjects but not in CFS patients. CONCLUSION: These results demonstrate that the L-Arg-induced activation of NK activity is mediated by NO and that a possible dysfunction exists in the NO-mediated NK cell activation in CFS patients.

Adjuvants, Immunologic↗
PubMed1998

P3a of event-related potential in chronic methamphetamine dependence.

To investigate the psychophysiological features of methamphetamine (MAP) dependence, we recorded auditory event-related potentials (ERPs) in 15 patients with MAP dependence and in 15 age-matched normal controls. ERPs were recorded during a standard oddball task and a read task similar to those employed by Squires et al. (Squires NK, Squires KC, Hillyard SA [1975] Two varieties of long-latency positive waves evoked by unpredictable auditory stimuli in man. Electroenceph Clin Neurophysiol 38:387-401). The patients with MAP dependence showed reduced P3a amplitude and area in the read task and delayed P3b latency with normal P3b amplitude and area in the oddball task. These results suggest that central noradrenergic dysregulation may persist after the remission of acute psychotic symptoms in MAP psychosis and that chronic MAP dependence would produce impairment of the frontal cortex.

Acoustic Stimulation↗
PubMed1998

Vertical transmission of hepatitis C virus: risk factors and infantile prognosis.

OBJECTIVES: To clarify the incidence and risk factors of the vertical transmission of hepatitis C virus (HCV) and to determine the prognosis of the carrier infants. METHODS: At our hospital, 1,941 non-pathological (non-HIV carriers) Japanese pregnant women were screened for anti-HCV antibodies. Sera of the antibody-positive women were examined by the reverse transcription polymerase chain reaction (RT-PCR) method, and the positive women and their infants were followed by testing HCV-related markers. RESULTS: The HCV carrier rate among the pregnant women was 3.5% (68/1,941). Four among the 65 infants (6.2%) who were successfully followed for more than 6 months developed the HCV carrier-state. Of all the risk factors examined, only the elevation (> or = 110 IU/l) of maternal serum alanine aminotransferase (ALT) was found to be significant for HCV vertical transmission. Seventy-five and 50% of the carrier infants manifested chemical hepatitis and seroconverted to an HCV-RNA-negative status, respectively, during the follow-up period. CONCLUSIONS: The frequency of HCV vertical transmission was 6.2%. Half of the carrier infants became seronegative for HCV-RNA. HCV vertical transmission was significantly affected by the maternal serum ALT level prior to delivery.

Adolescent↗
PubMed1998

A follow up study of myocardial involvement in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

OBJECTIVE: To investigate cardiac function in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) and clarify the clinical features of cardiomyopathy in MELAS. PATIENTS: 11 consecutive patients with MELAS (mean age at initial examination 11.3 years, range 4 to 16 years) were enrolled in the study. Six were followed for more than five years. RESULTS: On echocardiographic examination, three patients showed increased left ventricular end diastolic posterior wall thickness (LVPWTd), exceeding 140% of the normal value. Four patients, including these three, had an ejection fraction of less than 50%, and two also had increased left ventricular end diastolic volume (LVEDV) exceeding 140% of the normal value (%N). The LVPWTd%N was correlated positively with the LVEDV%N (R = 0.669, p < 0.05) and negatively with the ejection fraction (R = -0.6701, p < 0.05). One patient died of heart failure aged 22 years. CONCLUSIONS: The cardiomyopathy in MELAS is characterised by an abnormally thick left ventricular wall with progressive dilatation and poor left ventricular contraction developing over several years, indicating hypertrophic cardiomyopathy advancing to dilated cardiomyopathy.

Adolescent↗
PubMed1998

Event-related potentials during a selective attention task with short interstimulus intervals in patients with schizophrenia.

OBJECTIVE: To study selective attention in schizophrenia by examining event-related potentials during a dichotic listening task with short interstimulus intervals (ISIs). DESIGN: Prospective study. PARTICIPANTS: Twelve patients with schizophrenia in remission and 12 age-matched controls with no history of psychiatric or neurological illness. INTERVENTIONS: Participants were asked to push a button in response to target stimuli in either ear. OUTCOME MEASURES: Reaction time, correct response rate and results of electroencephalography recorded at 3 regions: mean segmental amplitudes between 0 and 200 ms and between 200 and 400 ms after stimuli and processing negativity (Nd), measured by the negative area during these periods. RESULTS: Distinct slow-positive potentials for unattended stimuli, which were elicited in a task with long ISIs in a previous report, did not emerge in either group in this study. Although the 2 groups did not differ significantly in terms of Nd area, in the controls the mean segmental amplitude for attended standard stimuli was significantly greater than that in the patients with schizophrenia. CONCLUSIONS: Impairment of selective attention in patients with schizophrenia is related to a lack of ability to focus attention on attended task-relevant stimuli during a selective attention task with short ISI.

Adult↗
PubMed1998

[Color M-mode Doppler analysis of left ventricular inflow in pediatric patients].

This study evaluated the clinical usefulness of analyzing left ventricular (LV) filling by color M-mode Doppler echocardiography in pediatric patients. The LV-filling patterns of color M-mode Doppler echocardiography were obtained by LV inflow in the apical 4-chamber or long-axis view, and the time difference between the occurrence of peak velocity at the mitral tip and in the apical region (M-AP) was calculated. The peak velocity at each depth was determined by adequate selection of the Nyquist limit by shifting the zero point after freezing the color M-mode. LV volume and posterior wall motion velocity were obtained simultaneously. The catheter-derived data were compared with echo-derived data in 7 patients (mean age 12.0 years). The M-AP correlated positively with the time constant of LV relaxation (tau; r = 0.83, p < 0.05), pulmonary capillary wedge pressure (r = 0.83, p < 0.05), and negatively with peak diastolic posterior wall motion velocity (r = -0.78, p < 0.05). The M-AP was compared with other echo-derived data between Group N (35 children with normal cardiac function, mean age 4.3 years) and Group F (12 children with LV ejection fraction less than 40%, mean age 9.5 years). The M-AP was significantly longer in Group F (53.3 +/- 14.0 vs 116.5 +/- 30.5 msec; p < 0.001), but there was no significant difference in the E/A or deceleration time of E between the 2 groups. In Group N, the E/A correlated to LV end-diastolic volume and heart rate, but the M-AP showed no correlation. In Group F, the M-AP correlated with the percentages of normal LV end-diastolic volume (r = 0.76, p < 0.01) and LV ejection fraction (r = -0.58, p < 0.05). The M-AP was not influenced by LV size or heart rate and could easily differentiate normal heart from failing heart, and thus this is a useful parameter for evaluating diastolic function in pediatric patients.

Adolescent↗
PubMed1998

[Remarkable increase of CD8+ CD11a+ and CD8+ CD57- T cells in patients with post-transfusion graft-versus-host disease].

We analyzed the distribution of two T cell subsets, CD8+ CD11a+ (CD8+ cytotoxic effector population) and CD8+ CD57- cells, in the peripheral lymphocytes of 3 post-operative patients with post-transfusion graft-versus-host disease (PT-GVHD) and 5 post-operative patients without PT-GVHD. The percentage of CD8+ CD11a+ cells in the PT-GVHD-negative control was 19 +/- 4%, and in the 3 patients with PT-GVHD, 69%, 66%, and 59%, respectively. The percentage of CD8+ CD57- cells in the PT-GVHD-negative control was 19 +/- 6%, and in the 3 PT-GVHD patients, 59%, 58%, and 55%, respectively. Significantly higher proportions of the two T cell subsets were consistently observed in the patients with PT-GVHD than in the PT-GVHD-negative control. These results suggest that the analysis of CD8+ T cell subsets may be useful for the simple and rapid laboratory diagnosis of PT-GVHD.

Acute Disease↗
PubMed1997

Remodeling of glycoconjugates on CD44 enhances cell adhesion to hyaluronate, tumor growth and metastasis in B16 melanoma cells expressing beta1,4-N-acetylglucosaminyltransferase III.

Beta1-4 N-acetylglucosaminyltransferase III (GnT-III) synthesizes bisecting N-acetylglucosamine structures on asparagine-linked oligosaccharides. Using B16-hm mouse melanoma cells stably expressing GnT-III activity as positive transfectants, the effect of bisecting N-acetylglucosamine on the function of CD44 was analyzed in association with adhesion to hyaluronate and tumor spread in mice. Transfection of GnT-III caused increased affinity of immunoprecipitated CD44 to erythro-agglutinating phytohemagglutinin, that preferentially recognizes bisecting N-acetylglucosamine, without affecting the surface CD44 amount, indicating an increase in bisecting N-acetylglucosamine residues on CD44 in positive transfectants. CD44-mediated adhesion to immobilized hyaluronate and the binding of fluorescence-labeled hyaluronate to the cell surface were increased in positive transfectants. The enhanced adhesion in positive transfectants was suppressed by the treatment with beta-N-acetylhexosaminidase, indicating that N-acetylglucosamine residues were responsible for the enhanced adhesion. Positive transfectants showed promoted CD44-mediated tumor growth and metastatic development in the spleen after subcutaneous inoculation into mice. These results indicate that glycosylation of CD44 due to GnT-III causes enhanced adhesion to hyaluronate, local tumor growth and metastatic growth in spleen, suggesting that the CD44-mediated adhesion and tumor spread can be modified through introduction of a glycosyltransferase gene.

Acetylglucosamine↗
PubMed1997

Auditory event-related potentials in panic disorder.

To investigate the psychophysiological features of panic disorder (PD), we recorded auditory event-related potentials (ERPs) in 12 patients with PD meeting the DSM-IV criteria and in 12 age-matched normal controls. The ERPs were recorded during a standard two-tone discrimination task (oddball task). The probabilities of the rare target (1200 Hz) and frequent non-target tones (1000 Hz) were 15 and 85%, respectively. The subjects were required to press a button in response to the rare target tones. Scalp electroencephalograms were recorded from Fz, Cz, Pz, C3, and C4. The State-Trait Anxiety Inventory and Manifest Anxiety Scale scores were assessed for clinical evaluation. Analysis of variance revealed that the N1 and N2 amplitudes for target tones and the N1 amplitude for non-target tones were significantly larger in the PD patients than those in the controls. The two groups did not differ significantly in P3 latency and amplitude. The larger N1 and N2 amplitudes in the PD patients are suggestive of alteration of early information processing in PD.

Adult↗
PubMed1997

Maternal-infant transmission of hepatitis G virus.

By a reverse transcriptase-polymerase chain reaction assay, we studied the risk of hepatitis G virus vertical infection in seven infants born to women positive for hepatitis G virus ribonucleic acid and hepatitis C virus antibody. Of these, three (42.9%) tested positive for hepatitis G virus ribonucleic acid and two (28.6%) had a carrier state. Intrauterine or birth canal infection seemed much more significant than the infection by breast-feeding.

Breast Feeding↗
PubMed1997

[Right atrial flap method for repair of partial anomalous pulmonary venous drainage into the high superior vena cava--case report].

We report an alternative method of repairing partial anomalous pulmonary venous return (PAPVR) wherein anomalous veins drain into the high portion of superior vena cava (SVC). A six year old girl, weighing 19 kg underwent cardiac catheterization for cardiomegaly. The study showed sinus venous defect and pulmonary veins anomalously drained from the right upper and middle lobe into the high SVC. Under cardiopulmonary bypass with aortic and bicaval direct cannulation, a 2-cm-wide pedicled flap made from the middle part of the right atrium (RA), was pulled into the SVC. The atrial flap divided the SVC from the ostium of the uppermost pulmonary vein (PV) to the ASD. This posterior tunnel drained anomalous PV blood into the left atrium. Postoperative echocardiogram and magnetic resonance imaging showed adequate space in the SVC and the PV channel. The patient maintained normal sinus rhythm after surgery. The advantage of this method is to minimize the risk of injuring the sinus node or sinus node artery, and to easily reconstruct both the SVC and PV channel without using prosthetic materials, even in patients with small RA.

Child↗
PubMed1997

[Repair of D-transposition of the great arteries associated with double aortic arch].

We report a case of D-transposition of the great arteries associated with double aortic arch. An aortic root angiogram revealed that the left-sided aortic arch was anterior and smaller than the right one and the descending thoracic aorta located on the left side of the spine. Balloon atrial septostomy was performed at one day of age. The patient underwent a simultaneous arterial switch procedure and division of the vascular ring at the isthmus of the left aortic arch through a median sternotomy incision at the age of 16 days. There was persistent postoperative difficulty in weaning the patient from the ventilator. Magnetic resonance images showed re-formation of pseudovascular ring by the connective tissue grown around the divided arch. At the age of 23 days, resection of the remnant of left aortic arch including the left subclavian artery and the diverticulum concomitant with vascular suspension procedure was performed through a left lateral thoracotomy. The patient was subsequently extubated without difficulty and was discharged from the hospital. It is though that a vascular suspension procedure and resection of the subclavian artery are necessary to avoid respiratory obstruction when the great arteries are in an anteroposterior position and Lecompte procedure is performed.

Aorta, Thoracic↗
PubMed1997

[A successful Konno's operation for subaortic stenosis progressed after total correction of partial atrioventricular septal defect associated with polysplenia].

Konno's operation was successfully performed on a small infant, weighing 3.8 kg. She underwent pulmonary artery banding on the 29th day of life under the diagnosis of partial atrioventricular septal defect with a small left ventricle, associated with polysplenia. Intracardiac repair was subsequently performed on the 45th day of life, which included atrial partition and mitral valvuloplasty. Eleven months after the second operation, wedge resection on the narrow subaortic fibrous lesion was done concomitant with mitral revalvuloplasty. However, repeated echocardiac study disclosed progression of subaortic stenosis. Cardiac catheterization performed at 2 years of age showed the pressure gradinet of 90 mmHg between the aorta and the LV. The aortic annulus and the subaortic lesion measured 10 mm and 4 mm in diameter respectively. Severe subaortic stenosis was created by protrusion of abnormal mitral tissue to the LV outflow, in addition by secondary circumferential fibrous tissue growth and hypertrophy of the ventricular septum. Konno's operation using on 18A Carbomedics valve was chosen for the certain relief of the subaortic stenosis. Although the operation required extensive ventriculotomy and septostomy because of the small aortic annulus, the postoperative course was uneventful. Two months after the operation echocardiography showed good LV function and low RV pressure of about 40 mmHg.

Aortic Valve Stenosis↗
PubMed1997

[A case of modified Fontan operation for corrected transposition of great arteries (I.D.D.) with atrial septal defect, ventricular septal defect, pulmonary stenosis, mitral atresia and hypoplastic left ventricle].

A 14-year-old boy with corrected transposition of the great arteries (I.D.D.), atrial septal defect, ventricular septal defect, pulmonary stenosis, mitral atresia and hypoplastic left ventricle was successfully operated. He had undergone modified Blalock-Taussig shunt at the age of two. After atrial septal defect was closed with bovine pericardial patch, small ventricular septal defects were closed directly through left ventricular incision. Then the incisional line on the left ventricle was extended to pulmonary artery. The stenotic and thickened pulmonary valve was excised. The upper part of the incisional line on the right atrium and that on the left ventricle were anastomosed. Consequently the connection between the right atrium and the pulmonary artery was able to be made through hypoplastic left ventricle. This case is extremely rare type in terms of mitral atresia and is classified as Group II, type B according to Eliot's classification. This type of repair is similar to Björk's method, however, we could not make use of left ventricular contraction because it was weak. The merit of this procedure was to be able to reconstruct blood tract without using artificial conduits.

Adolescent↗
PubMed1997

[An experience of the modified Norwood's operation for hypoplastic left heart syndrome with aberrant origin of right subclavian artery and persistent left superior vena cava--the procedure without total circulatory arrest and cardiac arrest].

We reported a successful case of the modified Norwood operation for a 21-day-old neonate with hypoplastic left heart syndrome (MS and AS) associated with an aberrant right subclavian artery and a persistent left superior vena cava. The modified Norwood operation was performed without total circulatory arrest and Cardiac arrest. A 4 mm Gore-Tex graft, which was anastomosed between the right carotid artery and the right pulmonary artery for systemic-pulmonary shunt, was used for cerebral perfusion during aortic arch reconstruction. Coronary perfusion was performed with a small cannula placed on the relatively large ascending aorta during anastomosis between the main pulmonary artery and the ascending aorta. Equine pericardial patch was used for aortic arch reconstruction and the ascending aorta was directly anastomosed to a part of the main PA. Postoperative course was uneventful and postoperative MRI revealed no stenosis of the aortic arch and the pulmonary artery.

Aorta, Thoracic↗