Biomedical subjects

H Sugimoto

Publications and source records attributed to H Sugimoto.

445 records · Page 25Linked to original sources

PubMedDate not supplied

Chemical shift and the double-line sign in MRI of early femoral avascular necrosis.

The double-line sign (DLS) on T2-weighted images in femoral avascular necrosis (AVN) is formed by a high-intensity rim at the reactive interface inside a low-intensity margin. A hypothesis has been advanced that the sign may be seen in early AVN whether or not there is bony sclerosis. On change of direction of the frequency-encoding axis, the high-intensity area rimmed with low-intensity margin was generated on the side where chemical shift misregistration artifact was seen. Transposition of frequency-encoding and phase-encoding axes yielded the same results. The thickness of the low-density rim was almost equal to the amount of expected offset distance due to chemical shift misregistration. Therefore, chemical shift misregistration artifact is the most reasonable explanation for the DLS observed in early femoral AVN.

Artifacts↗

PubMedDate not supplied

Effect of water fraction in selection of optimal TI value for STIR sequences.

OBJECTIVE: This article describes the effect of the water fraction in the selection of the optimal TI value in a STIR sequence. This effect has been given little consideration in previous studies. MATERIALS AND METHODS: Therefore, using both STIR combined with the Dixon method (opposed-phase STIR) and conventional STIR (in-phase STIR), we have investigated the effect of the water fraction in the selection of an optimal TI value for the STIR sequence. RESULTS: Our findings have indicated that the water protons rather than the olefinic protons (-CH = CH-) play a major role in the opposed-phase effect in vivo. CONCLUSION: Thus, it has been concluded that the most effective fat suppression can be achieved when the intravoxel phase cancellation effect between the water and lipid protons is maximal, rather than when the longitudinal magnetization of the lipid protons is minimal.

Adipose Tissue↗

PubMedDate not supplied

Surface strains in the anterior leaflet of the functioning mitral valve.

Abstract-The mitral valve (MV) is a complex anatomical structure whose function involves a delicate force balance and synchronized function of each of its components. Elucidation of the role of each component and their interactions is critical to improving our understanding of MV function, and to form the basis for rational surgical repair. In the present study, we present the first known detailed study of the surface strains in the anterior leaflet in the functioning MV. The three-dimensional spatial positions of markers placed in the central region of the MV anterior leaflet in a left ventricle-simulating flow loop over the cardiac cycle were determined. The resulting two-dimensional in-surface strain tensor was computed from the marker positions using a C0 Lagrangian quadratic finite element. Results demonstrated that during valve closure the anterior leaflet experienced large, anisotropic strains with peak stretch rates of 500%-1,000%/s. This rapid stretching was followed by a plateau phase characterized by relatively constant strain state. We hypothesized that the presence of this plateau phase was a result of full straightening of the leaflet collagen fibers upon valve closure. This hypothesis suggests that the MV collagen fibers are designed to allow leaflet coaptation followed by a dramatic increase in stiffness to prevent further leaflet deformation, which would lead to valvular regurgitation. These studies represent a first step in improving our understanding of normal MV function and to help establish the principles for repair and replacement.

Animals↗

PubMedDate not supplied

Middle ear imaging using virtual endoscopy and its application in patients with ossicular chain anomaly.

Virtual endoscopy (VE) is a recently developed technique to provide a realistic surface rendering of various organs, which can be applied to the use of three-dimensional (3D) studies of several lesions. However, its advantages in otological disease have not been well investigated. In this study, we evaluated the application of VE in patients with ossicular chain anomalies. Virtual middle ear endoscopy was a time-saving method, however, we needed the appropriate technical procedures of algorithm and reconstruction spacing to generate accurate 3D images of ossicles. We obtained virtual surgical views of middle ear structures and related anomalies, and confirmed by intraoperative findings that these images were mostly compatible with the actual lesions of ossicles. VE allowed an identification of the anatomy of the ossicles and adjacent structures simultaneously. The elements of the stapedial crura were clearly visualized with VE images in 93.3% of normal ears. Pathological ossicular chain findings such as malleus or incus fixation, dislocation and disruption, except footplate fixation were investigated successfully. One possible procedure, using alterable CT value in the obtained VE images on the monitor, is proposed for further detection of fine lesions of the ossicles. These observations suggest that virtual middle ear simulations accurately represent major intraoperative findings. This technique may have an important role in preoperative planning, surgical training, and/or postoperative evaluation in otology.

Adult↗

PubMedDate not supplied

Effect of ketone bodies on hyperglycemia and lactic acidemia in hemorrhagic stress.

BACKGROUND: To investigate the effect of hyperketonemia on altered glucose metabolism under stress conditions, we infused sodium D-3-hydroxybutyrate (3-OHB) into rats in hemorrhagic hypotension and evaluated the plasma concentration of substrates related to glucose metabolism. METHODS: Three groups of anesthetized rats (weight, 280 g to 320 g) were bled acutely, and their mean arterial pressures were maintained at 40 mm Hg. From 1 hour before hemorrhage to the end of the experiment, rats in the first group (n = 10) were infused with 3-OHB at a rate of 30 mumol/kg.min (3-OHB group), those in the second group (n = 10) received glucose and sodium bicarbonate (glucose group), and the remaining 10 rats received only sodium bicarbonate and no energy substrates (control group). Sodium bicarbonate was used to control the alkalizing effect of 3-OHB. RESULTS: Hyperketonemia (1158 +/- 30 mumol/L - 1618 +/- 154 mumol/L) occurred only in the 3-OHB group. Hyperglycemia and lactic acidemia during hemorrhagic shock were suppressed significantly compared with the control group. Plasma concentration of alanine was also lower compared with the control group. In the glucose group, although plasma lactate concentration was lower, plasma glucose concentration was not suppressed, and plasma alanine concentration was higher in comparison with the control group during hemorrhagic shock. There was no significant difference in plasma insulin concentration among the three groups. CONCLUSIONS: These results suggest that administered 3-OHB may suppress glycolysis during hemorrhagic shock.

3-Hydroxybutyric Acid↗

PubMedDate not supplied

The dimer and trimer of 3-hydroxybutyrate oligomer as a precursor of ketone bodies for nutritional care.

BACKGROUND: Ketone bodies have been considered as a means of providing energy because of their good penetration and rapid diffusion in peripheral tissues. However, because the currently available form of 3-hydroxybu-tyrate is the sodium salt, the sodium load is problematic. To avoid it, a mixture of dimer and trimer has been prepared as a precursor of D-3-hydroxybutyrate. The purpose of this study was to investigate whether and how the solution would be converted to monomers. METHODS: The plasma concentration of 3-hydroxybutyrate monomer was measured in 10 rats during infusion of dimer and trimer. Stepwise dilutions of the solution were incubated with serum and liver homogenates from five rats, serum samples from five volunteers, and a liver sample from one patient with liver injury. The solution also was incubated with carboxylesterase and triacylglycerol lipase. The concentration of monomer in the medium was measured after incubation. RESULTS: The plasma concentration of 3-hydroxybutyrate monomer reached 572 +/- 11 micromol/L 15 minutes after beginning infusion of the mixture at a rate of 25 micromol x kg(-1) x min(-1) and 270 +/- 40 micromol/L at a rate of 12.5 micromol x kg(-1) min(-1). The solution was converted completely to monomers when incubated with rat serum or liver homogenate for 10 minutes. The mixture also was hydrolyzed by human liver homogenate but not by serum. CONCLUSIONS: The dimer and trimer of 3-hydroxybutyrate can be converted rapidly to monomer in rat and human tissues. 3-Hydroxybutyrate oligomers could be an energy substrate for injured patients.

3-Hydroxybutyric Acid↗

PubMedDate not supplied

Drug effects on exercise-induced late asthmatic responses.

Disodium cromoglycate, prednisolone, beclomethasone and salbutamol were administered prior to the cycle ergometer exercise task separately to different groups of children with exercise-induced dual asthmatic reaction. Pre-treatment with disodium cromoglycate of ten asthmatics totally inhibited the dual reaction. Prednisolone treatment of eleven asthmatics and beclomethasone treatment of five asthmatics did not inhibit the early response but only the late response. Salbutamol treatment of ten asthmatics mainly inhibited the early phase reaction. Changes in neutrophil chemotactic activity correlated with airflow limitation in the disodium cromoglycate and prednisolone study, however, there were some discrepancies between the changes in FEV1 and neutrophil chemotactic activity in the beclomethasone and salbutamol studies. These findings suggest that exercise-induced dual asthmatic reaction are modified by disodium cromoglycate, prednisolone, beclomethasone or salbutamol in a mechanism which may be different in each drug and that there are similarities in the inflammatory responses in antigen- and exercise-induced dual asthmatic responses.

Albuterol↗

PubMedDate not supplied

PIVKA-II during perioperative period in patients with hepato-biliary-pancreatic diseases.

BACKGROUND/AIMS: In this study, we examined the influence of clinical treatments in the perioperative period upon PIVKA-II (plasma levels of protein induced by vitamin K absence or antagonist-II) in patients with hepatocellular carcinoma and pancreatobiliary diseases. METHODOLOGY: During a perioperative period, plasma PIVKA-II levels were measured in 144 patients with various hepatobiliary and pancreatic diseases by two types of EIA kit, using the conventional monoclonal antibody MU-3 and the new monoclonal antibody 19B7; Thrombotests were given at the same time. RESULTS: PIVKA-II of hepatocellular carcinoma patients showed higher reactivity with MU-3 than with 19B7. On the other hand, PIVKA-II of pancreatobiliary malignancies showed higher reactivity to 19B7 than it did to MU-3. In hepatocellular carcinoma patients, there was no correlation between PIVKA-II and Thrombotest levels; however, a significant correlation was found in patients with obstructive jaundice due to pancreatobiliary cancer. PIVKA-II levels decreased gradually to normal range within about 2 weeks after the curative operation. PIVKA-II levels in the patients receiving antibiotics containing N-methyl-thiotetrazole without administration of vitamin K remained high as long as the antibiotics were administered, but decreased to normal range as soon as the administration was finished. CONCLUSIONS: PIVKA-II which is produced by hepatocellular carcinoma may be different from that produced by obstructive jaundice due to pancreatobiliary malignancies. The clinical treatments in perioperative period, such as the administration of antibiotics containing N-methyl-thiotetrazole or vitamin K, readily influence PIVKA-II levels. Therefore, abnormal PIVKA-II levels must be carefully interpreted in the diagnosis of hepatocellular carcinoma and pancreatobiliary malignancies.

Adult↗

PubMedDate not supplied

Intraoperative diagnosis of pancreatic cancer extension using IVUS.

BACKGROUND/AIMS: Pancreatic cancer easily invades retroperitoneal tissue, especially the portal vein and extrapancreatic nerve plexus. We evaluated the diagnostic accuracy of intraportal endovascular ultrasonography in portal vein and extrapancreatic nerve plexus invasion. METHODOLOGY: Intraportal endovascular ultrasonography was performed in 78 cases of pancreatic cancer (head 67, body 8, total 3). Intraportal endovascular ultrasonography was performed intraoperatively from the superior mesenteric vein with an 8-French, 20-MHz intravascular ultrasound catheter. Three-dimensional intraportal endovascular ultrasonography was constructed by volume rendering. RESULTS: Intraportal endovascular ultrasonography visualized the portal vein as an echogenic band with a thickness of 0.5 mm to 1.0 mm. The diagnostic criterion of portal vein invasion was obliteration of this echogenic band. Intraportal endovascular ultrasonography visualized segment II of the extrapancreatic nerve plexus as the high-echoic area around the inferior pancreaticoduodenal artery. The diagnostic criterion of extrapancreatic nerve plexus invasion was low-echoic infiltration around the inferior pancreaticoduodenal artery. The sensitivity, specificity, and overall accuracy of intraportal endovascular ultrasonography for diagnosis of portal vein invasion was, respectively, 97.4%, 92.5%, and 94.9%. The values for diagnosis of extrapancreatic nerve plexus invasion, respectively, were 94.4%, 97.1%, and 96.2%. Three-dimensional intraportal endovascular ultrasonography depicted the invasion area as a defect of the portal vein wall. CONCLUSIONS: Intraportal endovascular ultrasonography detected subtle portal invasion and provided accurate portal invasion area which was useful for portal vein an reconstruction. Intraportal endovascular ultrasonography could also diagnose the extrapancreatic nerve plexus invasion of segment II.

Aged↗

PubMedDate not supplied

Changes in hepatic lobe volume in hepatocellular carcinoma after transcatheter arterial and percutaneous transhepatic portal embolization.

BACKGROUND/AIMS: Determining changes in liver volume after preoperative percutaneous transhepatic portal embolization (PTPE) for hepatocellular carcinoma (HCC) is essential in managing the operation safely. We evaluated the alterations in liver volume by means of ultrasonography (US) and computed tomography (CT). METHODOLOGY: We studied 12 patients scheduled for hepatectomy with HCC. Transcatheter arterial embolization (TAE) and PTPE of the right portal vein were performed preoperatively. Liver volume was evaluated before and after PTPE. RESULTS: The volume of the right lobe measured by CT significantly decreased from 709+/-266 cm3 before PTPE to 589+/-209 cm3 18 days after PTPE (P=0.0021). The volume of the left lobe significantly increased from 382+/-97 cm3 to 477+/-84 cm3 (P=0.0008). US volume measurement of the left lateral segment revealed a temporary volume increase 2 days after PTPE and a significant linear correlation between the hypertrophy ratios from 2 to 18 days after PTPE (r=0.946, P<0.0001). CONCLUSIONS: Preoperative PTPE allowed a compensatory volume increase in the remnant liver. A sonographic estimation is useful in confirming the dynamic alteration of liver hypertrophy. Care must be taken for appropriate timing of a CT scan for volume measurements, considering the drawbacks associated with irradiation.

Adult↗

PubMedDate not supplied

Purification and characterization of human fibroblast derived differentiation inducing factor for human monoblastic leukemia cells identical to interleukin-6.

A differentiation inducing factor for human monocytic leukemia cells was purified to homogeneity from conditioned medium of WI-26VA4, a human fibroblast cell line. The purification scheme consisted of micro bead silica gel chromatography, hydroxyapatite chromatography, gel filtration chromatography, chromatofocusing and reverse phase high performance liquid chromatography. The purified protein was almost homogeneous when determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal sequence analysis. The protein has a molecular weight of approximately 27,000 and an isoelectric point of 5.4. The sequence of the first 13 N-terminal amino acid residues was consistent with that of B-cell stimulatory factor 2 (interleukin-6) except for the absence of the N-terminal proline. The purified factor induced differentiation of human monocytic leukemia U-937 cells into a monocyte/macrophage pathway.

Amino Acid Sequence↗

PubMedDate not supplied

Common pulmonary vein atresia: a successfully corrected case.

Common pulmonary vein atresia is a rare congenital cardiac anomaly in which there is no communication between the confluence of the pulmonary veins and the heart or the major systemic venous system. We successfully treated this disease in a 5-day-old boy by performing an anastomosis of the left atrium to the common pulmonary vein. Only one patient with this lesion who survived this procedure has been reported in the literature. Early recognition of this lesion and immediate surgical intervention are the only way to save the patient's life.

Echocardiography↗

PubMedDate not supplied

Reversible MR findings of hemolytic uremic syndrome with mild encephalopathy.

We report the reversible MR findings in a 7-year-old girl with hemolytic uremic syndrome and mild encephalopathy. The splenium of the corpus callosum showed isointense to low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, representing local edema. These findings returned to near normal on MR images obtained 1 week later. The patient recovered without CNS impairment.

Brain↗