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Biomedical subjects

H Sakuma

Publications and source records attributed to H Sakuma.

At least 55 records · Page 3Linked to original sources
PubMed1999

Influence of felodipine on left ventricular hypertrophy and systolic function in orthotopic heart transplant recipients: possible interaction with cyclosporine medication.

BACKGROUND: Concentric left ventricular (LV) hypertrophy develops early in orthotopic heart transplant (OHT) recipients. To compare the effects of a calcium channel blocker, felodipine, versus diuretics on LV hypertrophy and LV systolic function repeated magnetic resonance imaging studies were performed in OHT recipients. Cyclosporine levels and neurohormones were also measured to explore potential interactions with treatment. METHODS: Twenty-two patients were randomized at baseline (2 months after OHT) to receive felodipine or diuretic treatment. Before and after 4 months of treatment (n = 19), LV dimensions and LV mass (Simpson's rule) were measured. The relationship between circumferential fiber shortening (two-shell cylindrical model) and end-systolic wall stress was used as a measure of load-independent LV contractility. Neurohormones were measured at the beginning and end of the treatment period, and cyclosporine levels and blood pressures were additionally measured during treatment. RESULTS: At baseline, the felodipine and diuretic groups did not differ in LV mass, wall stress, and fiber shortening. During felodipine treatment LV mass decreased (p < 0.01) and tended to increase during diuretics treatment (p = 0.06). Afterload-corrected fiber shortening did not change during felodipine treatment, but decreased (p < 0.01) with diuretics. Changes in LV mass were positively correlated with cyclosporine levels (r = 0.70) in the diuretics group, but not in the felodipine group. CONCLUSIONS: In OHT recipients during diuretic treatment, progression of LV hypertrophy occurs in relation to cyclosporine plasma levels and is accompanied by impairment of systolic contractile function. Felodipine induces regression of LV hypertrophy, while systolic contractile function is preserved. During felodipine treatment, regression of LV hypertrophy is unrelated to cyclosporine levels. Thus, felodipine seems to attenuate the hypertrophic effect of cyclosporine on transplanted hearts.

Analysis of Variance↗
PubMed1999

Large-scale sequencing of the rabbit corneal endothelial cDNA library.

PURPOSE: This study sought to identify novel or active genes in corneal endothelial cells with description of the gene-expression profile. METHODS: We performed the single-pass sequencing of 1,000 clones from a rabbit corneal endothelial cDNA library. Inserts of the library were amplified by polymerase chain reaction (PCR), sequenced, and compared with several databases. We used four database similarity search programs: FASTA, BLASTN, TBLASTX, and BLASTX. RESULTS: Of the sequences generated, 618 (61.8%) showed sequence homology with known genes, whereas 192 (19.2%) matched previous reported expression sequence tags (ESTs) and 174 (17.4%) showed no sequence similarity. Among the homologous clones to known genes are collagen type VIII, secreted protein acidic and rich in cysteine (SPARC), lysyl oxidase, phosphatidylcholine-2-acylhydrolase, and thrombospondin. Several matched ESTs, and no matched clones that showed high frequency were also detected. CONCLUSION: Large-scale sequencing can be useful in obtaining a profile of the active genes. Several ESTs showed relatively frequent expression, suggesting that these genes may have important functions in the corneal endothelium.

Animals↗
PubMed1999

Three-dimensional coronary magnetic resonance angiography with injection of extracellular contrast medium.

RATIONALE AND OBJECTIVES: To evaluate serial changes of the signal intensity and the contrast-to-noise ratios of the coronary arteries on three-dimensional (3D) coronary magnetic resonance angiography (MRA) after an injection of extracellular contrast medium, and to demonstrate the feasibility of this method for the diagnosis of coronary artery abnormalities. METHODS: Five healthy volunteers and two patients with Kawasaki disease and an anomalous coronary artery were studied. Coronary MRAs of the left anterior descending artery and the right coronary artery were obtained using a fat-suppressed 3D MRA sequence before and 0 to 5, 10 to 15, 20 to 25, and 30 to 35 minutes after administration of Gd-DTPA-BMA. RESULTS: Administration of the contrast agent provided a significant increase in the signal intensity and contrast-to-noise ratio. Aneurysm of the left anterior descending artery in Kawasaki disease and the proximal course of the anomalous right coronary artery, which were not well depicted on precontrast 3D MRA, were clearly demonstrated after contrast injection. CONCLUSIONS: The current study demonstrated that the use of an extracellular gadolinium contrast agent can significantly improve the clinical usefulness of 3D coronary MRA.

Adolescent↗
PubMed1999

REM sleep components predict the response to initial treatment of infantile spasms.

PURPOSE: The phasic inhibition index (PII) is the rate of the simultaneous occurrence of rapid eye movement bursts (RBs) and phasic chin muscle activity (PCMA) during rapid eye movement sleep (REMS). PII is low insofar as physiologically occurring REM-related phasic inhibition acts on chin muscles. Previously we found that PII was significantly higher in patients with infantile spasms (ISs) who had a recurrence of convulsions than in patients with ISs who exhibited no recurrence. We aimed to predict the response of patients with ISs to conventional anticonvulsants (AEDs) by means of REMS components including PII, expecting to facilitate avoidance of potentially hazardous hormonal therapy. METHODS: REMS, recorded before the beginning of any medication, was retrospectively examined in 15 patients with ISs. The patients were classified into two groups according to the response to initial treatment with conventional AEDs. Conventional AEDs were enough to control the spasms in six good responders (GRs), whereas further hormonal therapy was required in nine poor responders (PRs) to control the spasms. RESULTS: The amount of REMS was significantly lower in patients with ISs than in controls. GRs had less REMS than did PRs, although no significant difference was observed. Although the frequencies of RB and PCMA showed no significant differences among GRs, PRs, and controls, the average PII value in PRs (12.6+/-3.4; mean+/-SD) was significantly (p < 0.001) higher than that in GRs (6.1+/-1.7). CONCLUSIONS: PII is a useful parameter for differentiating GRs from PRs.

Anticonvulsants↗
PubMed1999

[A case received pre-exposure immunization against rabies by intradermal injection of rabies vaccine because of allergic reaction to the component of the vaccine].

A female, 25 years of age, came to our clinic to receive pre-exposure immunization against rabies. In another hospital she was tested to find out whether she was allergic to the components of rabies vaccine (PCEC) manufactured by the Chemo-Sero-Theraptic Research Institute (Kaketsuken) by cutaneous reaction using a 2,000-fold diluted PCEC. She showed a positive reaction. In our clinic she was again examined by skin test using 0.1 ml of 10-fold diluted PCEC. She showed wheal and flare reaction. Further we tested using 0.05 ml and 0.1 ml of non-diluted PCEC. Her skin reaction did not increase by several mm in diameter. So we decided to immunized her against rabies with intradermal injections of PCEC instead of subcutaneous injections that is indicated by the manufacturer. The second intradermal injections were done to right and left forearms a week later. Then the third shot was given 4 weeks after the second. At 2 weeks after the third injection her blood sample was taken to measure anti-rabies antibody titer by ELISA method with Platelia rabies kit (Diagnostic Pasteur, France). She had 6.7 U/ml of anti-rabies ELISA antibody that was much higher than the protective level (0.5 IU/ml) officially recognized by WHO. Therefore, it is concluded that she had produced sufficiently high level of anti-rabies antibody with intradermal injection of PCEC. It is reasonably recommended to investigate further if the intradermal injection of PCEC will be an effective method as a pre-exposure immunization against rabies.

Adult↗
PubMed1999

Hypertrophic cardiomyopathy: MR measurement of coronary blood flow and vasodilator flow reserve in patients and healthy subjects.

PURPOSE: To evaluate coronary blood flow per gram of myocardial mass and vasodilator flow reserve in patients with hypertrophic cardiomyopathy (HCM) and in healthy subjects by using breath-hold velocity-encoded cine (VEC) magnetic resonance (MR) imaging. MATERIALS AND METHODS: Twenty-nine patients with HCM and nine healthy volunteers were examined. Fast VEC MR images were obtained in an oblique imaging plane perpendicular to the coronary sinus before and after intravenous injection of dipyridamole (0.56 mg/kg). The products of mean velocity and cross-sectional area of the vessel were integrated to measure blood flow. Breath-hold cine MR images encompassing the entire left ventricle were acquired to quantify the left ventricular mass. RESULTS: In the basal state, the coronary blood flow per gram of myocardial mass was 0.74 mL/min/g +/- 0.23 in healthy subjects and 0.62 mL/min/g +/- 0.27 in patients with HCM. After administration of dipyridamole, coronary blood flow in patients with HCM increased to a level significantly less than that in healthy subjects (1.03 mL/min/g +/- 0.40 vs 2.14 mL/min/g +/- 0.51; P < .01), resulting in a severely depressed flow reserve ratio in patients with HCM compared with that in healthy subjects (1.72 +/- 0.49 vs 3.01 +/- 0.75; P < .01). CONCLUSION: Breath-hold VEC MR imaging is a noninvasive technique for evaluating coronary flow per gram of myocardial mass and coronary flow reserve.

Blood Flow Velocity↗
PubMed1999

A case of traumatic high thoracic myelopathy presenting dissociated impairment of rostral sympathetic innervations and isolated segmental sweating on otherwise anhidrotic trunk.

A 3 year-old boy developed flaccid paraplegia, anesthesia below T3 and impaired vesical control immediately after a car accident. Three months later, the pupils and their pharmacological reactions were normal. Thermal sweating was markedly reduced on the right side of the face, neck, and shoulder and on the bilateral upper limbs, and was absent below T3 except for band like faint sweating on T7 sensory dermatome. The left side of the face, neck and shoulder showed compensatory hyperhidrosis. Facial skin temperature was higher on the sweating left side. Cervico-thoracic MRI suggested almost complete transection of the cord at the levels of T2 and T3 segments. We discussed the pathophysiology of the dissociated impairment of rostral sympathetic innervations and isolated segmental sweating on otherwise anhidrotic trunk.

Accidents, Traffic↗
PubMed1999

Cytophagic histiocytic panniculitis improved by combined CHOP and cyclosporin A treatment.

In a 31-year-old Japanese man with cytophagic histiocytic panniculitis (CHP) remission was achieved by a combination of combined chemotherapy CHOP and cyclosporin A treatment. He was admitted to our hospital in January 1994 with recurrent high fever of 40.2 degrees C and tender and violaceous subcutaneous nodules on his trunk, arms and legs. He developed pancytopenia, hemorrhagic diathesis, liver dysfunction. Histological examination of the biopsied subcutaneous nodule revealed a lobular panniculitis with fat necrosis and a massive infiltration of histiocytes phagocytosing nuclear debris. He was treated initially with 40 mg/day prednisolone. However, following a reduction in prednisolone dosage, his symptoms reappeared. CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) therapy was then initiated. Three courses of CHOP treatment alleviated his symptoms and cyclosporin A was used to maintain his condition for 15 months. His medication was then discontinued and he has been in complete remission for 10 months. Combined treatment of cyclosporin A and CHOP combined chemotherapy was shown to be effective for this patient with severe CHP.

Adult↗
PubMed1998

Isolation and characterization of the human X-arrestin gene.

Arrestins are signal transduction modulators that quench the activated state of receptors. X-arrestin (ARRX) is specifically expressed in the red-, green-, and blue-sensitive cone photoreceptors, and is most likely a modulator of cone phototransduction. The human gene for X-arrestin at Xcen-Xq22 has been shown to be approximately 20kb in size and to consist of 17 exons and 16 introns. The exons are generally small, including exon 16 of 10bp, and are clustered into three groups, separated by the two largest introns. This gene structure is generally similar to that of S-antigen, the rod photoreceptor arrestin. There is remarkable similarity, however, among the individual exons between the two genes in that 10 of the exons are identical in size. The 5' upstream region of the X-arrestin gene contains TATA and CAAT boxes, typical of genes expressed in a tissue-specific manner, in contrast to the S-antigen gene, which lacks these promoter sequences. The promoter elements, common to both the X-arrestin and S-antigen genes, include the Ret-1/PCE-1 (PCE-1-like in X-arrestin), CRX, and the thyroid hormone/retinoic acid-responsive sequences, the former two being present in a number of photoreceptor-expressed genes. Three CRX-binding elements, 15bp apart, are present in a cluster. The common promoter elements between the cone-expressed genes, X-arrestin and color opsins, include the TATA box, PCE-1, and CRX-binding sequences, the combination of which might be important for directing cone-specific expression.

Amino Acid Sequence↗
PubMed1998

Dynamic contrast-enhanced MR imaging of the entire breast with spectral-selective inversion fast three dimensional sequence.

Dynamic contrast-enhanced images with high spatial and temporal resolutions were acquired with a fast 3D spoiled gradient echo (SPGR) sequence using spectral selective inversion recovery (IR) pulse. Five healthy volunteers and 12 patients with 14 pathologically proven breast lesions were studied. Fat suppressed volume image data covering the entire breast were obtained with a sufficient spatial resolution (0.9 x 1.5 x 3.0 mm3) and an imaging time of 57 s. By using the criteria including peripheral enhancement and presence of spiculation, sensitivity, specificity, and accuracy in detecting malignant lesions were 88.9, 80.0 and 85.7%, respectively. Although the C/N and S/N ratios were approximately 30% less than those of the conventional fat suppressed 3D technique, fast 3D SPGR imaging with spectral IR method demonstrated sufficient image quality for both time intensity analysis and morphological evaluation of the breast lesions with a data acquisition time less than half of the conventional method. This technique can substantially improve spatial and temporal resolutions of dynamic MR images of the breast and will be useful in evaluating malignant and benign breast lesions.

Adipose Tissue↗
PubMed1998

Value of blood pool contrast agents in magnetic resonance angiography of the pelvis and lower extremities.

Our objective was: (1) to determine the appropriate dose of new ultrasmall superparamagnetic iron oxide particles for magnetic resonance angiography (MRA). This agent comprised of a single iron oxide crystal stabilized with a carbohydrate-polyethylene glycol coat (PEG-Ferron/NC 100150 injection); (2) to determine the proper flip angle for PEG-Ferron-enhanced 3 D time-of-flight (TOF) MRA sequence; and (3) to compare the enhancement of peripheral vessels following PEG-Ferron and GdDTPA-BMA. MRA parameters were: TR/TE = 50/2.1 ms, NEX = 1, FOV = 30 x 30 x 1.8 cm, and matrix = 256 x 128 x 64. In anesthetized beagle dogs (n = 10), the effects of PEG-Ferron and GdDTPA-BMA on regional signal were monitored for 45 min and compared. The lowest dose of PEG-Ferron (0.05 mmol/kg) produced the best enhancement of primary, secondary and tertiary vessels. The flip angle 60 degrees provided better enhancement than 20 degrees on contrast enhanced images. Unlike GdDTPA-BMA, PEG-Ferron allowed prolonged delineation (> 45 min) of the pelvis and lower extremities circulation. PEG-Ferron provided greater Contrast-to-noise ratio CNR (80.2 +/- 6.2, P < 0.05) than GdDTPA-BMA (63.5 +/- 2.5). It may be possible for blood pool contrast-enhanced 3 D TOF MRA to provide valuable information for visualization of vascular tree including guiding interventions.

Animals↗
PubMed1998

Normal bladder wall morphology in Gd-DTPA-enhanced clinical MR imaging using an endorectal surface coil and histological assessment of submucosal linear enhancement using [14C]Gd-DOTA autoradiography in an animal model.

OBJECTIVE: The purpose of this study was to investigate normal bladder wall morphology in gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging using an endorectal surface coil and to perform histological assessment of submucosal linear enhancement with experimental [14C]-gadolinium-tetraazacyclododecane-tetraacetic acid (Gd-DOTA) autoradiography. METHODS AND MATERIAL: MR imaging of the bladder was performed using an endorectal coil in 13 consecutive patients with bladder carcinoma and T1-, T2-, and Gd-DTPA-enhanced spin-echo images of the bladder wall were compared. After injection of [14C]Gd-DOTA into a hamster, autoradiograms of the bladder wall were obtained and compared with serial histological sections. RESULTS: The normal bladder wall appeared as a homogeneous layer of intermediate intensity on T1-weighted images. After administration of Gd-DTPA, the bladder wall was visualized as three layers: an inner thin layer of low intensity, a middle layer of marked enhancement, and a thick outer layer of intermediate intensity. The autoradiograms demonstrated dense accumulation of [14C]Gd-DOTA in the submucosal layer. Thus, the inner, middle, and outer layers corresponded to the mucosa, submucosa, and muscularis propria, respectively. The thickness of the bladder wall demonstrated on T2-weighted images was almost equal to that of the outer layer on enhanced T1-weighted images. Thus, T2-weighted images revealed only the muscle layer as an intermediate-intensity band. In the preliminary clinical study, MR imaging invariably showed accurate stages of the bladder carcinoma in 13 patients. CONCLUSION: In MR imaging of the normal bladder wall, the submucosa was strikingly enhanced after Gd-DTPA administration, separating the bladder wall into three layers. This may have a potential role in the staging of bladder tumors.

Animals↗
PubMed1998

Evaluation of altered myocardial high energy phosphate metabolism in patients on maintenance dialysis using phosphorus-31 magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES: Assessment of left ventricular metabolism and function is important in patients on maintenance dialysis because congestive heart failure occurs quite frequently and has a poor prognosis. The purpose of this study was to evaluate the changes of myocardial high energy metabolism in dialysis patients by using phosphorus-31 (31P) magnetic resonance (MR) spectroscopy. METHODS: Phosphorus-31 spectra were obtained from anteroseptal wall of the heart in six normal subjects (mean age, 24 +/- 1 years) and 14 dialysis patients (mean age, 52 +/- 11 years), using a 1.5-tesla clinical MR system. Four patients had previous history of heart failure. Echocardiography was performed in all patients to evaluate left ventricular (LV) hypertrophy and LV function. RESULTS: The averaged ratio of phosphocreatine (PCr)/beta-adenosine triphosphate (beta-ATP) in dialysis patients (1.15 +/- 0.25 mean +/- standard deviation), was significantly lower than that in healthy subjects (1.63 +/- 0.21; P < 0.01). There was no significant difference in PCr/beta-ATP ratios between the non-LV hypertrophy group (1.21 +/- 0.24; n = 7) and the LV hypertrophy group (1.09 +/- 0.24; n = 7). The averaged PCr/beta-ATP ratio in four patients with history of heart failure (0.96 +/- 0.18) was significantly lower than that of the 10 patients without history of heart failure (1.22 +/- 0.23; P < 0.05). CONCLUSIONS: These results indicate that patients on maintenance dialysis have decreased PCr/beta-ATP ratio and 31P MR spectroscopy can provide noninvasive assessment of altered high energy phosphate metabolism.

Adenosine Triphosphate↗
PubMed1998

Familial amyotrophic lateral sclerosis with widespread vacuolation and hyaline inclusions.

This report presents a familial amyotrophic lateral sclerosis (FALS) patient with widespread vacuoles and hyaline inclusions strongly immunostained with the anti-superoxide dismutase (SOD1) antibody. The overall pathologic similarity between our non-SOD1-linked FALS patient and transgenic mice expressing a mutated human SOD1 gene suggests that common pathogenetic mechanisms other than an SOD1 mutation exist in the development of these diseases.

Aged↗
PubMed1998

[Regional variations of the cytokeratin expression along the guinea pig cochlear turn].

Expression of cytokeratin (Ck) proteins in the guinea pig cochlea was examined using a recently developed immunohistochemical method for celloidin section. This method has allowed us to observe a whole cochlea with excellent morphological preservation in a visual field under the light microscope. Anti-Ck antibodies FIL-7 (AE-1, Signet Lab.) and NCL-CK19 (Novocastra Lab.) stained all supporting cells of the organ of Corti, in which pillar cells, Deiters' cells, Hensen's cells, and Boettcher's cells showed a strong reaction. The histochemical labeling of pillar and Deiter's cells showed a gradual increment from the base to the apex. The immunohistochemically stained area in Hensen's cells increased toward the apex, which was attributed mainly to the increase in both the number and size of Hensen's cells from the base to the apex. In an electron-microscopic examination, changes in histochemical labeling of Hensen's cells did not appear from the base to the apex. Close examination revealed that reaction precipitates were distributed along a filament structure which seemed to correspond to the cytokeratin filaments. These results suggest that the Ck filaments give elasticity and flexibility to the supporting cells in the organ of Corti and provide mechanical strength to the organ of Corti at the upper turns, which vibrate with larger amplitudes, and that the Ck filaments in the supporting cell must be of considerable importance as a tuning mechanism. Immunohistochemical labeling for Ck was also observed in the spiral prominence cells, outer sulcus cells, interdental cells, and Reissner's membrane. The positively stained area in the outer sulcus increased from the apex to the base.

Animals↗
PubMed1998

Increased lung uptake of iodine-123-MIBG in diabetics with sympathetic nervous dysfunction.

UNLABELLED: Scintigraphy with 123I-MIBG and 201TI was compared in patients with various diseases including diabetes mellitus, with and without sympathetic nervous dysfunction. This study was done to assess lung uptake of these tracers semiquantitatively. METHODS: Thirty-eight patients with diabetes mellitus, seven patients with dilated cardiomyopathy (DCM), 12 patients with hypertrophic cardiomyopathy (HCM) and eight healthy subjects were studied. Sympathetic nervous dysfunction was observed in 13 of the 38 diabetic patients. Simultaneous imaging with 123I-MIBG and 201TI was performed. The ratio of lung to total injected dose count and washout rate in the lung were calculated from dynamic images acquired in the initial 2 min and static images acquired at 15 min and at 4 hr after injection of the tracers. RESULTS: Lung uptake of 123I-MIBG at 4 hr was significantly increased in the diabetic group as compared with those in the other groups. In diabetic patients with sympathetic nervous dysfunction, the lung uptake ratio of 123I-MIBG at 4 hr was significantly higher than that in the diabetic patients without sympathetic nervous dysfunction, due to decreased clearance of 123I-MIBG from the lung. On the other hand, increased lung uptake of 201TI was observed in DCM patients at both 15 min and 4 hr. There was no significant difference between lung uptake of 201TI in diabetic patients and that in healthy subjects. CONCLUSION: Lung uptake of 123I-MIBG was increased and lung washout of 123I-MIBG was decreased in diabetic patients with sympathetic nervous dysfunction, while lung uptake of 201TI was not altered. lodine-123-MIBG scintigraphy of the lung may provide information on sympathetic nervous activity in diabetic patients. It is a promising method for studying the kinetics of norepinephrine in the lung because MIBG is taken up in the lung by the same mechanism as norepinephrine.

3-Iodobenzylguanidine↗
PubMed1998

[Polyclonal B-cell lymphocytosis with clinical and hematological features resembling hairy cell leukemia].

A 49-year-old man was admitted to our hospital for investigation of splenomegaly and lymphocytosis. He had no significant past history and was not a smoker. Physical examination revealed massive splenomegaly and no palpable superficial lymph nodes. Hematological examination showed a hemoglobin concentration of 10.5g/dl, a platelet count of 9.8 x 10(4)/microliter, and a leukocyte count of 21.2 x 10(3)/microliter with 70% abnormal lymphocytes. In May-Giemsa stained blood films, the abnormal lymphocytes had round nuclei, abundant, pale cytoplasm, and slightly serrated edges. Phase-contrast microscopic and scanning electron microscopic examinations revealed many long surface villi. Tartrate-resistant acid phosphatase activity in these cells was negative. The abnormal lymphocytes had a CD5-, CD10-, CD11a+, CD11c+, CD19+, CD20+, CD22+ phenotype. These features were similar to those described for a variant form of hairy cell leukemia (HCL-Japanese variant). However, studies of Ig gene rearrangement and expression of sIg revealed a polyclonal proliferation of B cells. On the basis of these findings, this case was diagnosed as hairy B-cell lymphoproliferative disorder, a recently described condition characterized by polyclonal B-cell lymphocytosis and features resembling HCL-Japanese variant. Serological assays for antibodies against Epstein-Barr virus suggested a past infection. Splenectomy alleviated the anemia and thrombocytopenia, but not the lymphocytosis.

Antigens, CD↗