Electron microscopic observations on the islet alpha cells of the domestic fowl pancreas.
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Animals↗
Biomedical subjects
H Sakuma
Publications and source records attributed to H Sakuma.
Serial P-31 MR spectroscopy after fructose infusion in patients with chronic hepatitis.
Serial changes in phosphorus metabolites after intravenous administration of fructose were compared between five healthy volunteers and five patients with chronic hepatitis by means of phosphorus-31 magnetic resonance (MR) spectroscopy. P-31 spectra were obtained every 5 minutes after intravenous drip infusion of 20% fructose at a dose of 0.5 g/kg of body weight. In the healthy volunteers, phosphomonoesters (PME) increased to 338% +/- 76% of the preadministration value at 15-20 minutes. Inorganic phosphate (Pi) was depleted in the first 15 minutes, then rebounded to 260% +/- 67% of the initial value. beta-adenosine triphosphate decreased to less than 50% of its initial value and then gradually recovered. In patients with chronic hepatitis, the increase of PME at 15-20 minutes (151% +/- 49% of the preadministration value) was significantly less than that in healthy volunteers (P less than .05). In addition, the rebound of Pi at 35-40 minutes (126% +/- 42%) was significantly less than that in healthy volunteers (P less than .05). In conclusion, P-31 MR spectroscopy with fructose administration is valuable in the functional evaluation of diffuse liver diseases.
Adenosine Triphosphate↗
First-pass contrast-enhanced inversion recovery and driven equilibrium fast GRE imaging studies: detection of acute myocardial ischemia.
The purpose of this study was (1) to monitor the dynamic effects of T1-enhancing and magnetic susceptibility contrast material on normal canine myocardium using inversion recovery (IR)- and driven equilibrium (DE)-prepared fast gradient-recalled echo (GRE) sequences and (2) to determine the relative value of T1-enhancing and magnetic susceptibility contrast material in detecting regions of ischemia in the same animal. Normal dogs (n = 5) and dogs with acute occlusion of the left anterior descending (LAD) coronary artery (n = 11) were studied using a 1.5-T MR imager. ECG-gated fast IR-prepared GRE images were acquired using TI/TR/TE of 700/7.0/2.9 msec and a flip angle of 7 degrees. Fast DE-prepared GRE images were obtained using a flip angle of 12 degrees and a DE delay/TR/TE of 60/10.2/4.2 msec. Sequential images were acquired to monitor transit of 0.05 mmol/kg gadodiamide injection and 0.2 and 0.4 mmol/kg sprodiamide injection. On slice-nonselective IR fast GRE images, gadodiamide caused significant enhancement of the normal myocardium and the left ventricular (LV) chamber blood. In dogs with LAD occlusion, the ischemic region was defined as an area of low signal intensity (SI). On DE-prepared GRE sequences, administration of sprodiamide resulted in a substantial decrease in signal from normal myocardium and LV chamber blood in normal dogs. In animals subjected to LAD occlusion, this contrast medium produced a transient decrease in SI from normal myocardium (P < .05) and no significant change in SI from ischemic myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of Variance↗
Cardiovascular applications of magnetic resonance flow and velocity measurements.
With recent developments of MR techniques for blood flow measurements, qualitative and quantitative information on both flow volume and flow velocity in the major vessels can be obtained. MR flow quantitation uses the phase, rather than the amplitude of the MR signal, to reconstruct the images. Previous validation studies have demonstrated the accuracy of the phase shift techniques for measuring flow velocities. This technique is now being applied successfully in the cardiovascular system to quantify global and regional ventricular function, valvular heart disease, pulmonary artery disease, thoracic aortic disease, congenital heart disease, and ischemic heart disease.
Blood Flow Velocity↗
Improved reproducibility in measuring LV volumes and mass using multicoil breath-hold cine MR imaging.
There is a generally recognized need for improvement in quality of fast cardiac MR images. Consequently, breath-hold cine MR images were obtained with multiple surface coils connected to phased array receivers, and C/N, intra-observer and inter-observer variabilities for LV volumes and mass were evaluated. Two sets of short-axis images of the LV, one with multiple surface coils and another with a body coil, were acquired in eight subjects with a fast cine MR sequence using k-space segmentation (TR/TE = 7/2.2 msec, temporal resolution = 56 msec). C/N with multicoil imaging was 32.2 +/- 7.6 (mean +/- SD), significantly higher than that with a body coil (11.0 +/- 3.3, P < .01). The mean percentage differences in intra-observer and inter-observer measurements with multicoil imaging were significantly better than those with a body coil. In conclusion, multicoil imaging provides significant gain in C/N on breath-hold cine MRI of the heart. In addition, intra-observer and inter-observer reproducibilities are improved with multicoil imaging.
Adult↗
Breath-hold MR measurements of blood flow velocity in internal mammary arteries and coronary artery bypass grafts.
Breath-hold velocity-encoded cine MR (VENC-MR) imaging is a feasible method for measuring phasic blood flow velocity in small vessels that move during respiration. The purposes of the current study are to compare breathhold VENC-MR measurements of flow velocities in the internal mammary arteries (IMA) with nonbreath-hold measurements and to characterize the systolic and diastolic flow velocity curves in a cardiac cycle in native IMA and IMA grafts. Flow velocity in 30 native IMA and 8 IMA grafts were evaluated with a breath-hold VENC-MR sequence with K-space segmentation and view-sharing reconstruction (TR/TE = 16/9 msec, VENC = 100 cm/s). In 10 native IMA, nonbreath-hold VENC-MR images were acquired as well for comparison. Breath-hold VENC-MR imaging showed significantly higher systolic and diastolic peak velocities in native IMA (43.1 cm/second +/- 15.0 and 10.0 cm/second +/- 4.8), in comparison to those of nonbreath-hold VENC-MR imaging (27.6 cm/second +/- 10.2 and 7.3 cm/second +/- 3.9, P < .05). The diastolic/systolic peak velocity ratio in the IMA grafts (.88 +/- .41) was significantly higher than that in native IMA (.24 +/- .08, P < .01). Interobserver variability in the flow velocity measurement was less than 4%. Breath-hold VENC-MR imaging demonstrated higher peak flow velocity in the IMA than nonbreath-hold VENC-MR imaging. This technique is a rapid and effective method for the noninvasive assessment of blood flow velocity in IMA grafts.
Adult↗
MR imaging characterization of postischemic myocardial dysfunction ("stunned myocardium"): relationship between functional and perfusion abnormalities.
Stunned myocardium has been detected in patients treated successfully with thrombolytic agents. The hypothesis of this study was that fast gradient echo (GRE) imaging could be used to characterize the regional functional and perfusion abnormalities that are indicative of myocardial stunning. This study was designed to monitor and correlate the extent of wall thickness and perfusion abnormalities as determined by fast (segmented k space) cine and contrast enhanced GRE imaging, respectively. Dogs were subjected to left circumflex (LCX) coronary artery occlusion (15 min) followed by 30-minute reperfusion (n = 8). Perivascular flow probes were used to continuously measure flow in left anterior descending (LAD) and LCX coronary arteries. Short-axis inversion recovery prepared fast GRE and cine images were acquired at baseline, at occlusion, and at 1, 10, and 30 minutes of reflow. Regional signal intensity and percent systolic wall thickening were determined at 26 equally spaced circumferential positions to compare the extent of functional and perfusion abnormalities. During occlusion and reperfusion, the ischemic region was demonstrated on contrast-enhanced images as a hypointense and hyperintense region, respectively. During occlusion, the extent of the perfusion defect (32% +/- 2% of the circumference of the equatorial slice) correlated closely (r = .74) with the extent of contractile dysfunction (35% +/- 2%). After reperfusion, there was transient recovery in the percent wall thickening (26% +/- 4% vs 36% +/- 4% normal), coinciding with the reactive hyperemic response, but this was followed by a significant decline in wall thickening at 10 minutes (19% +/- 4%) and 30 minutes (12% +/- 2%). Fast MR imaging may be useful to monitor postischemic myocardial abnormalities after thrombolytic therapy and the response to pharmacologic interventions.
Animals↗
Comparison of breath-hold multishot echo-planar and respiratory triggered fast-spin-echo sequences for T2-weighted MRI of liver lesions.
The purpose of this study was to evaluate the usefulness of multishot echo-planar imaging in detecting liver tumors in comparison with respiratory triggered T2-weighted fast-spin-echo (FSE) imaging. Thirty-two patients with 70 focal liver lesions were imaged using a 1.5-T high speed MR imager. Eight-shot echo-planar images covering the whole liver were acquired during a single breath-hold period. FSE images were acquired with respiratory triggering in approximately 4 minutes. Lesion detectability and image quality of the two pulse sequences were analyzed qualitatively. Quantitative analysis was performed by means of signal-to-noise and tumor-liver contrast-to-noise analysis. Lesion detectability was comparable in both solid (86.3% vs 90.2%: .3 < P < .5) and nonsolid lesions (89.5% vs 100%: .3 < P < .5) between echo-planar and FSE images. Echo-planar imaging provided significantly reduced image artifact, better lesion conspicuity, and anatomic detail compared with FSE imaging. The signal-to-noise and contrast-to-noise ratios of echo-planar images were significantly higher than those of FSE images. Breath-hold eight-shot echo-planar imaging can be an alternative to T2-weighted FSE imaging because it can provide comparable image quality in a substantially decreased acquisition time.
Adult↗
Assessment of hepatic portal perfusion using T2 measurements of Gd-DTPA.
Recently, perfusion imaging has been of increasing interest in MRI. We applied this method for semiquantitative evaluation of hepatic parenchymal portal blood flow in patients with diffuse liver damage. Twenty patients with diffuse hepatic damage were divided according to the Child's Classification and studied. Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was administered into the superior mesenteric artery (SMA), and a dynamic series of T2*-weighted fast low angle shot (FLASH) images was obtained. We evaluated relative regional portal blood volume (rrPBV), mean transit time (MTT), and relative regional portal blood flow (rrPBF). The relationship between the rrPBV, rrPBF, and plasma indocyanine green retention rate test at 15 minutes (ICGR15 was also evaluated in 12 patients. Both rrPBF and rrPBV are significantly decreased in Child B & C patients compared with Child A patients. On the other hand, the MTT is significantly prolonged in Child B & C patients compared with Child A patients. Significant correlations were also noted between rrPBV and ICGR15 and between rrPBF and ICGR15. By means of selective catheterization into the SMA, we were able to estimate rrPBV, rrPBF, and MTT. This method may play a clinical role for assessment of regional portal perfusion in various diseases with diffuse liver damage.
Adult↗
Treatment of chronic type B aortic dissection with endovascular stent-graft placement.
A 74-year-old man with chronic aortic dissection was treated with an endovascular stent graft, fabricated from expanded polytetrafluoroethylene and a Z-stent. It was placed in the true lumen to close an entry tear. Closure was obtained immediately and thrombosis of the false lumen at the descending thoracic aorta was observed on computed tomography (CT) obtained 1 week later. No procedure-related complications developed. The patient is doing well with no adverse events including aortic rupture or aortic branch ischemia.
Aged↗
Plus/minus screening of rabbit corneal endothelial cDNA library.
Plus/minus screening of the rabbit corneal cDNA library was performed using corneal and iris RNA as probes. Thirteen clones were isolated: three ferritin H-chains, a NADH-ubiquinone oxidoreductase B22 subunit, an alpha 1 type VIII collagen, a 25 KDa FKBP-506 binding protein (FKBP25), a thrombospondin 2, and six unknown clones. Although proteins translocated from these isolated mRNA are not corneal specific, they play an important role in the cornea. None of the isolated known mRNAs maps to chromosome 1, 16, or 20. These clones, thrombospondin excepted, were not observed in the high frequency clones in the profile of the aortic endothelial cDNA library.
Amino Acid Sequence↗
Fast 3D dynamic MR imaging of the liver with MR SmartPrep: comparison with helical CT in detecting hypervascular hepatocellular carcinoma.
Dynamic magnetic resonance (MR) imaging with SmartPrep was compared with dynamic enhanced helical computed tomography (CT) for the detection of hepatocellular carcinoma (HCC). Thirty patients with 49 HCCs were studied. Arterial-phase MR images using with SmartPrep were significantly superior to arterial-phase CT in detecting small lesions (< or = 2 cm) (85.3% vs. 67.6%, P < .05). In addition, in six recurrent tumors after arterial chemoembolization, dynamic MR imaging with MR SmartPrep technique was superior to helical CT in detecting of recurrent tumors.
Adult↗
Evaluation of thoracic aortic dissection using breath-holding cine MRI.
OBJECTIVE: Our goal was to determine if breath-hold cine MRI in transaxial planes can be used for the evaluation of thoracic aortic dissection instead of conventional cine MRI since rapid imaging is required in this clinical setting. MATERIALS AND METHODS: Twelve patients with thoracic aortic dissection were imaged using a 1.5 T imager. Breath-hold images were acquired with fast cine MR sequence (TR/TE = 9/2.8, 20 degrees flip angle) using segmented k-space data acquisition. Conventional non-breath-hold cine MR images (TR/TE = 22/7.5, 35 degrees flip angle, 2 averages) were taken with flow and respiratory compensation. RESULTS: Sharpness of edges of the vessels on fast cine MR images was better than that on conventional cine MR images in 34 (57%) of 60 images. Inhomogeneous blood signal in aortic lumen due to motion artifacts was found in 2 (3%) of fast cine MR images and in 15 (25%) of conventional cine MR images. The contrast-to-noise ratios of fast cine MR images were significantly better than those of conventional cine MR images (26.4 +/- 9.1 vs. 18.5 +/- 10.1; p < 0.05) when the region of interest for noise was placed to include ghosting artifacts. CONCLUSION: Breath-hold cine MRI is a rapid technique that gives high quality images of thoracic aortic dissection and can provide a diagnosis in < 10 min of imaging time.
Aged↗
MR assessment of normal brain development in neonates and infants: comparative study of T1- and diffusion-weighted images.
PURPOSE: This study was designed to compare the sensitivity of T1- and diffusion-weighted images for the assessment of brain maturation in human brains. METHODS: T1- and diffusion-weighted images were obtained in 32 children without neurological abnormalities or growth retardation. The ages at which signal intensity changes of white matter on T1-weighted images and diffusional anisotropy appeared were compared. RESULTS: In the optic radiation, diffusional anisotropy was observed in neonates < 1 month old, whereas signal intensity became high after 1 month old. In the frontal lobe, diffusional anisotropy began to appear after 1 month of age, but signal intensity became high after 6 months of age. These visual findings were confirmed statistically by quantitative analysis using signal intensity ratios and anisotropic ratios. Similar findings were observed in the external capsule and the genu of the corpus callosum. CONCLUSION: In conclusion, diffusional anisotropy is a sensitive indicator of brain maturation in neonates and infants and precedes signal intensity change on T1-weighted images.
Brain↗
Clinicopathological and immunophenotypic studies on 12 cases with B cell chronic lymphocytic leukemia.
To clarify the histogenesis of B cell chronic lymphocytic leukemia (BCLL), clinicopathological and immunophenotypic studies were performed using a large panel of monoclonal antibodies on 12 cases with BCLL including three cases with prolymphocytic/chronic lymphocytic leukemia (CLL/PL). Immunophenotypically, CD19 and CD20 were positive for all cases of this series and CD5, CD21, CD22, CD23, CD25, CD38, Leu-8, KB-61, and bcl-2 protein were expressed in variable proportion from case to case. CD10, however, did not react. No alkaline phosphatase (ALP) positive cases were found. The phenotype of BCLL was similar to that of B cells of the mantle zone (MZ) of secondary follicle in the lymph node. It is therefore postulated that the neoplastic cells of BCLL in these cases might be derived from B cells of the MZ. Moreover, the cells possibly originated from the lymphocytes located in the inner layer of the MZ, since ALP+ B cells are usually observed in the outer layer of the MZ. The pseudofollicular (PF) pattern was observed in four biopsied lymph nodes among five cases tested, but no such a pattern in an aspiration clot of bone marrow. These four cases consisted of three cases with CLL and a case with CLL/PL. The immunohistochemical study showed that there were many proliferating cells showing Ki-67+ in the PF area of the lymph nodes. In these cases, leukemic cells might have developed from the PF area of the lymph node.
Aged↗
Multiple pulmonary nodules caused by zygomycosis in a patient without predisposing factors.
We report a case of a 61-year-old male without any predisposing factors. His X-ray film showed multiple nodular lesions in bilateral lung fields. Open lung biopsy revealed Zygomycetes in the granuloma. The patient was treated with amphotericin B and miconazole, and remains alive more than 32 months later.
Amphotericin B↗
Reduced response of cardiac norepinephrine release to isometric handgrip exercise in heart failure.
In order to evaluate the relation of cardiac norepinephrine (NE) release to left ventricular function, blood was taken simultaneously from the coronary sinus (CS) and the aorta (A) in 19 patients with heart diseases, at rest and during isometric handgrip exercise (IHG) at 30% of their maximal contraction. Plasma NE was analyzed by Renzini's THI method. The concentrations of plasma NE at rest were 397 +/- 66 (S.E.M.) ng/liter in CS and 292 +/- 50 in A. IHG significantly increased NE to 578 +/- 88 in CS and to 462 +/- 85 in A (p less than 0.001). Estimated NE release from the heart (deltaNE = NECS - NEA) correlated inversely to left ventricular end-diastolic pressure at rest (r = -0.520, p less than 0.05) and during IHG (r= -0.689, p less than 0.01). The changes in deltaNE induced by IHG correlated to the slope of the left ventricular function curve (r=0.618, p less than 0.01). It is concluded that the response of cardiac NE release to exercise is reduced in patients with depressed cardiac function.
Blood Pressure↗