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Biomedical subjects

Hiroyuki Fukuda

Publications and source records attributed to Hiroyuki Fukuda.

At least 55 records · Page 3Linked to original sources
PubMed2004

Electronic videoendoscopic laryngostroboscopy.

Color images obtained using electronic videoendoscopic laryngostroboscopy (EVLS) were presented and the utility of this technique for the diagnosis of dysphonia was discussed in this paper. Stroboscopic evaluations of laryngeal lesions were performed using a rhinolaryngeal electronic videoendoscope system employing a single-plate simultaneous color charge-coupled device (CCD) chip method. Twenty patients underwent electronic videoendoscopic laryngostroboscopy. A Karl Storz laryngostroboscope Pulsar was connected to this system and laryngeal lesions were assessed. The potentialities of laryngostroboscopy using this system were evaluated. Clear stroboscopic images were obtained in all patients. Multiple still images during vocal fold vibration were acquired using an optional function. The laryngostroboscope is not compatible with conventional systems employing a single-plate red, green, and blue (RGB) surface scanning method. However, the system used was successfully connected to a laryngostroboscope. EVLS appears to be a powerful new tool for the diagnosis of dysphonia.

Adult↗
PubMed2004

Excitatory neurotoxic properties of pontamine sky blue make it a useful tool for examining the functions of focal brain parts.

Pontamine sky blue (PSB) is used in brain studies to mark the position of microelectrode and micropipette tips. However, few studies have been made on the effects of PSB on neurons; therefore we examined these effects. When puffed on isolated sensory ganglion cells of rats, PSB increased membrane conductance, depolarized membrane potential, and reduced the amplitude of action potentials. When dripped on frog sympathetic ganglion, much like hexamethonium, PSB decreased the amplitude of compound action potentials of the postganglionic strand. A bath application of PSB to sartorius muscle fibers that had been treated with tetrodotoxin depolarized the membrane potential and increased the frequency and amplitude of miniature end-plate potentials. All these effects were reversible. When injected into the rat's pontine part corresponding to the location of the canine pontine defecation reflex center, PSB produced repetitive colorectal contractions and irreversibly abolished them in response to anal-canal stimulation. The excitatory and blocking effects of PSB and its staining ability make it a useful tool for examining the functions of focal brain parts.

Action Potentials↗
PubMed2003

Analysis of the non-covalent interaction between metal ions and the cysteine-rich domain of protein kinase C eta by electrospray ionization mass spectrometry.

Effect of zinc and other metal ions on the folding of the protein kinase C (PKC) surrogate peptide (PKCeta-C1B) was analyzed intact under neutral conditions by electrospray ionization mass spectrometry (ESI-MS). ESI-MS spectrum of 64ZnCl(2)-folded PKCeta-C1B clearly showed that PKCeta-C1B coordinates specifically two atoms of zinc, and that the two thiol protons are lost in each zinc ion coordinate center. 113CdCl(2)-folded PKCeta-C1B also showed stoichiometry of two cadmium atoms that was proved by addition of EDTA. The dissociation constants of zinc- and cadmium-folded PKCeta-C1B in the phorbol 12,13-dibutyrate binding (PDBu) were similar (0.66 and 0.81 nM) with different B(max) values (46.4 and 71.4%). The difference would reflect higher coordination potency of cadmium ion that was demonstrated by ESI-MS when PKCeta-C1B was folded by 1:1 mixture of zinc and cadmium ions. In contrast, 63CuCl(2)-treated PKCeta-C1B did not show any copper-coordinated peak, instead a molecular mass less than 6 mass units smaller than that of apo-PKCeta-C1B was observed. The multiple charge mass envelope of copper-treated PKCeta-C1B shifted to that of the lower mass charge state like zinc-treated PKCeta-C1B. These data suggest that the copper treatment formed three intramolecular S-S bonds to abolish the PDBu binding of PKCeta-C1B.

Cysteine↗
PubMed2003

Adenoviral GDNF gene transfer prevents motoneuron loss in the nucleus ambiguus.

We examined neuroprotective effects of an adenoviral vector encoding glial cell line-derived neurotrophic factor (AxCAhGDNF) on the lesioned adult rat motoneurons in the nucleus ambiguus. After vagal nerve avulsion, AxCAhGDNF, AxCALacZ (adenovirus encoding beta-galactosidase gene) or PBS was inoculated into the jugular foramen. Four days after the avulsion and treatment with AxCALacZ, the animals expressed beta-galactosidase activity in the lesioned motoneurons in the nucleus ambiguus. The animals avulsed and inoculated with AxCAhGDNF showed immunolabeling for GDNF in the nucleus ambiguus on the treated side and expression of virus-induced human GDNF mRNA transcripts in the brainstem tissue that contained the nucleus ambiguus of the treated side. The treatment with AxCAhGDNF after avulsion prevented the loss of lesioned motoneurons in the nucleus ambiguus, ameliorated the choline acetyltransferase immunoreactivity, and also suppressed the activity of nitric oxide synthase in these neurons. These results indicate that adenovirus-mediated GDNF gene transfer may prevent the degeneration of motoneurons in humans after either vagal nerve injury or recurrent laryngeal nerve injury.

Adenoviridae↗
PubMed2003

Assessment of cancer cell differentiation in small hepatocellular carcinoma by computed tomography and magnetic resonance imaging.

AIM: To study whether cancer cell differentiation in small hepatocellular carcinoma (HCC) can be assessed by computed tomography (CT) and magnetic resonance (MR) imaging. METHODS: We retrospectively evaluated the relationship between cancer cell differentiation in 127 HCC 3 cm or less in diameter (113 patients) and CT and MR images. Images were reviewed in a consensus conference by three authors (SA, TY, and ME). Histopathological diagnosis of HCC was made from liver specimens obtained by sonographically guided biopsy. RESULTS: The degree of histological differentiation of cancer cells was significantly different between HCC that were isodense with liver parenchyma in both artery-dominant and equilibrium phases in contrast-enhanced CT and tumors that were hyperdense in the artery-dominant phase and iso- or hypodense in the equilibrium phase (P = 0.0054), as well as tumors that were iso- or hypodense artery-dominant and hypodense equilibrium (P = 0.0002). Histological differentiation of lesions that were hyperintense in T1-weighted images and hypointense in T2-weighted images differed significantly from those with the opposite MR characteristics (P = 0.0122). In T1-weighted fat-suppression images and T2-weighted images, respectively, the degree of histological differentiation was significant between the hypointense/hyperintense and the hyperintense/hypointense patterns (P < 0.0001), as well as the hyperintense/isointense (P = 0.0296), the hyperintense/hyperintense (P = 0.0434), and the isointense/hyperintense (P = 0.0171). Using these differences an equation was developed that could determine with 76% accuracy whether the tumors were well or less-well differentiated. CONCLUSION: CT and MR imaging patterns were useful in predicting the degree of histological differentiation of cancer cells in HCC.

Adult↗
PubMed2003

Metal contents in the liver of patients with chronic liver disease caused by hepatitis C virus. Reference to hepatocellular carcinoma.

BACKGROUND/AIMS: The aim of this study was to investigate the relationship between trace metals and the prevalence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or hepatic cirrhosis caused by hepatitis C virus (HCV). METHODS: We measured the contents of copper, iron, and zinc in HCC tissue (n = 112), dysplastic nodules (n = 7), and liver parenchyma in patients with (n = 112) and without (n = 12; 7 with grade F3 fibrosis, 5 with grade F4 fibrosis) HCC. Metals were quantified in thin-needle biopsy specimens using the particle-induced X-ray emission method (PIXE). RESULTS: Copper level in liver parenchyma was higher in patients with HCC than in those without HCC (p < 0.01), while there was no such difference in hepatic iron. In patients with grade F4 fibrosis, copper content in the liver parenchyma was higher in the presence of HCC than in its absence (p < 0.05). Multiple regression analysis showed that the only factor significantly associated with the coexistence of HCC in HCV-positive patients with chronic liver disease was the copper level in the liver parenchyma. CONCLUSIONS: Hepatic copper overload may contribute to the development of HCC in HCV-positive patients with chronic hepatitis or cirrhosis.

Adult↗
PubMed2003

Cervical emphysema secondary to pneumomediastinum as a complication of childbirth.

Pneumomediastinum and cervical emphysema usually occur following esophageal or chest trauma. Rarely do they occur as a complication of childbirth, and only approximately 200 such cases have been reported in the literature worldwide. We describe a new case, and we review the clinical picture, pathophysiology, and management of these conditions. In view of the head and neck symptoms of pneumomediastinum and cervical emphysema during labor--which include dyspnea, cough, sore throat, pain on swallowing, and dysphagia--otolaryngologists might be consulted and should therefore be aware of these conditions in order to recognize and treat them.

Adult↗
PubMed2002

Isoaspartate formation at position 23 of amyloid beta peptide enhanced fibril formation and deposited onto senile plaques and vascular amyloids in Alzheimer's disease.

Senile plaques and amyloid-bearing vessels consisting of fibrillar amyloid beta peptides (A beta) are characteristic neuropathological features of Alzheimer's disease (AD). A beta undergo spontaneous post-translational modifications, such as isomerization and racemization, at their aspartyl residues in AD brains. Here we present evidence that A beta isomerized at position 23 are deposited on plaques and vascular amyloids using an anti-isomerized A beta antibody. In vitro experiments showed that isomerization at position 23, but not position 7, enhanced aggregation. Furthermore, A beta with the Dutch mutation, but not the Flemish mutation, also showed greatly enhanced aggregation. These results suggest that mutations or modifications at positions Glu 22 and Asp 23 have a pathogenic role in the deposition of A beta. The development and progression of sporadic AD may be accelerated by spontaneous isomerization at position 23 of A beta.

Aged↗
PubMed2002

Automated column-switching high-performance liquid chromatography system for quantifying N-methyl-D- and -L-aspartate.

The occurrence and biological significance of the D-amino acids, N-methyl-D-aspartate (NMDA) and N-methyl-L-aspartate (NMLA), have been recently studied in a variety of living organisms. In this study, we established a highly sensitive and reliable fluorometric HPLC system for determining levels of N-methyl-aspartate (NMA). The system comprises fluorescent derivatization of NMA with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and two chromatographic steps: one that separates NMA from other primary amino acids in reverse-phase mode and another that enantioseparates NMDA and NMLA in a normal-phase mode. These two steps are linked by an automated column-switching system. A simple pretreatment step with o-phthalaldehyde to remove primary amino acids that can interfere with sensitivity is also described. The detection limit for NMDA is as low as 5fmol and the correlation between peak heights and concentrations between 5fmol and 1pmol is satisfactory (r=0.999). Following sample preparation and separation using the column-switching HPLC system, more than 80% of NMDA was recovered from rat liver homogenates spiked with NMDA. This method was employed to determine the levels of NMDA in tissues from bivalves and the results obtained were consistent with the values reported previously.

4-Chloro-7-nitrobenzofurazan↗
PubMed2002

Small hepatocellular carcinoma: assessment with T1-weighted spin-echo magnetic resonance imaging with and without fat suppression.

OBJECTIVE: We examined the detectability of small hepatocellular carcinomas (HCCs) and the factors that affect hyperintensity of small HCC on T1-weighted images (T1W) by using T1-weighted fat-suppressed images (T1FS). METHODS: Thirty-nine HCCs (29 patients) measuring 30 mm or less were enrolled. The mean size of HCCs was 21.0+/-4.9 mm. Spin-echo T1W, T2-weighted images (T2W), and T1FS were obtained using a 1.5 T system. We evaluated the detectability in each sequence by receiver-operating-characteristic (ROC) analysis and the tumor-to-hepatic parenchyma contrast-to-noise ratio (CNR), the variance in the detectability among all interpreters with each sequence, and the presence or absence of improvement in the detectability by interpreting T1FS in addition to conventional T1W plus T2W. The contents of fat, copper, and iron in histologically diagnosed HCCs showing hyperintensity on both T1W and T1FS were measured. For determination of heavy metals, we used a particle induced X-ray emission analytical instrument. RESULTS: ROC analyses revealed that T1FS were superior to T1W and T2W in detecting small HCCs (0.900+/-0.017 for T1FS, 0.859+/-0.019 for T1W, and 0.745+/-0.030 for T2W). The detectability by interpreting T1FS in addition to conventional T1W plus T2W was improved (0.931+/-0.013 for the conventional images and 0.973+/-0.008 for the conventional images plus T1FS, P<0.001). The detected lesions on T1FS demonstrated favorable CNR values. The copper content in the cancer and the ratio of the copper content in the cancer to that in the non-cancerous tissue were 275.4+/-219.0 microg/g dry weight, 6.9+/-5.5 in HCCs showing hyperintensity on both T1W and T1FS. Both were significantly higher (P<0.05). CONCLUSION: T1FS showed excellent sensitivity and specificity in detecting small HCCS irrespective of the experience of interpreters. The use of T1FS suggested the involvement of copper might be one of the factors in hyperintensity of HCCs on T1W.

Adipose Tissue↗
PubMed2002

Diagnosis of gallstone composition in magnetic resonance imaging: in vitro analysis.

OBJECTIVE: To elucidate the cause of the signal intensity of gallstones on magnetic resonance (MR) images and to determine whether MR imaging would enable the prediction of the composition of gallstones. MATERIALS AND METHODS: 50 gallstones removed by cholecystectomy from 50 patients were used for in vitro study. All 50 gallstones were examined by MR imaging using a body phantom. After imaging, all gallstones were cut into two pieces, and the MR appearances were compared with their cross-sections. Chemical analysis was subsequently performed on 32 gallstones. RESULTS: On T2-weighted (T2W) images, 24 of 50 gallstones showed high signal intensities only in their center. These central high intensities seen on T2W images corresponded to the clefts filled with fluid within gallstones. In 45 of 50 gallstones there were high signal intensity areas in central and/or peripheral regions on T1-weighted (T1W) images. On T1W images, not only the clefts within gallstones but also other regions were seen as high intensity, and these regions had a brown to black color, coarse structure, and contained much copper. CONCLUSION: MR imaging can visualize the structures and compositions of gallstones in detail.

Calcium Carbonate↗
PubMed2002

New visualization technique with a three-dimensional video-assisted stereoendoscopic system: application of the BVHIS display method during endolaryngeal surgery.

A three-dimensional video-assisted stereoendoscopic system (3D video system) developed by the Shinko Optical Company, Ltd. (Tokyo, Japan), and referred to as the binocular vision by horizontal image shifting display method (BVHIS display method), has been developed to digitally process ordinary video signals obtained with a video camera connected to a direct videolaryngoscope. The three-dimensional video system provides the surgeon with stereoendoscopic video images and enhances the ability of the surgeon to perform delicate endoscopic procedures. The three-dimensional video-assisted stereoendoscopic laryngosurgical procedure and its underlying principles are described in this paper. A total of 12 patients with laryngeal lesions causing dysphonia underwent three-dimensional video-assisted stereoendoscopic laryngosurgery. Although the video image obtained with the BVHIS display method is only pseudo-three-dimensional, this method enables the surgeon to perceive both depth perception and realism. We describe a surgical procedure using this new visualizing technique and the underlying principles of the technique. Preoperative and postoperative evaluations of the patients' vocal functions are also described. This system is a useful tool for the treatment of laryngeal lesions causing dysphonia.

Adult↗
PubMed2002

Increased metabolizing activities of the tricarboxylic acid cycle and decreased drug metabolism in hepatocellular carcinoma.

The aim of this study was to determine the metabolizing activities in the liver of patients with hepatocellular carcinoma (HCC). Thin-layer chromatography autoradioluminography was used to measure metabolizing activities. Succinate-producing activity (SPA) was used as an indicator of metabolizing activity of the tricarboxylic acid (TCA) cycle in mitochondria, and diazepam-N-demethylating activity (DZ-DA), diazepam-3-hydroxylating activity (DZ-HA) and tolbutamide-methyl-hydroxylating activity (TB-HA) as indicators of drug metabolizing activities by P-450. SPA and drug-metabolizing activity of HepG2 cells were examined to compare with those of human liver specimens. Liver biopsy specimens of 30 patients and surgical specimens of eight patients with HCC were studied. SPA of HepG2 cells was as high as that of human tumor tissue, and DZ-DA, DZ-HA and TB-HA were undetectable in HepG2 cells. SPA and DZ-HA of non-tumor tissue in biopsy samples were significantly higher than those in resected liver specimens (P < 0.05). In biopsy specimens, SPA was significantly higher in tumor tissue than in non-tumor tissue (P < 0.05), and DZ-DA, DZ-HA and TB-HA were significantly lower in tumor tissue (P < 0.01). SPA was significantly higher in large tumors (>/=30 mm) than in small tumors <30 mm (P < 0.05), and TB-HA was significantly lower in large tumors than in small tumors (P < 0.01). DZ-DA and TB-HA significantly decreased with the progression of the tumor differentiation (P < 0.05). In conclusion, HCC has increased metabolizing activities of the TCA cycle and decreased drug-metabolizing activities.

Carcinoma, Hepatocellular↗
PubMed2002

Digital image processing of laryngeal lesions by electronic videoendoscopy.

OBJECTIVES: To present electronic videoendoscopy of the larynx with digital image processing and to discuss this endoscopic technique from the standpoint of diagnostic usefulness of laryngeal lesions. STUDY DESIGN: Electronic videoendoscopic evaluation of laryngeal lesions with digital image processing. METHODS: Seventy patients underwent electronic videoendoscopy without digital image processing and, subsequently, with the digital image processing function. Of these, 15 patients with white lesion of the vocal fold and laryngeal neoplasms were assessed in the study. Clinical assessments made before enhancement of digital image processing function were compared with those after enhancement in 15 patients. RESULTS: Of the 15 patients observed, the clinical diagnoses of two patients were changed after enhancement. Both patients underwent endolaryngeal microsurgery with histopathological examination of the removed lesions, which confirmed the definitive diagnosis. The clinical diagnoses of both patients after enhancement were compatible with histopathological diagnoses. CONCLUSIONS: The enhanced color images provided by this system are superior in both quality and resolution to those obtained by conventional flexible fiberoptic endoscopy with a video camera. This system should be a valuable tool for the diagnosis of laryngeal lesions.

Aged↗
PubMed2002

Irregularity of parenchymal echo patterns of liver analyzed with a neural network and risk of hepatocellular carcinoma in liver cirrhosis.

OBJECTIVE: In this study, we scored the hepatic parenchymal echo patterns as the coarse score (CS) analyzed with a neural network in cirrhosis patients and calculated the variations in CS as the coefficient of variation, and evaluate their usefulness as predictor of the development of hepatocellular carcinoma (HCC). METHODS: The relationship between the degree of variation in CS and histopathological findings was assessed in 10 autopsied livers fixed in formalin. The degree of intrahepatic variation in CS was calculated as the coefficient of variation of CS (CVCS). Irregular regeneration of liver cells in autopsied livers was classified into two categories, slight and severe. A total of 56 cirrhosis patients were prospectively followed to evaluate the predictors of HCC. RESULTS: A significant positive correlation was observed between CVCS and the coefficient of variation of the diameter of the regenerative nodules. Coefficient variation of nodule diameter and CVCS in patients in whom irregular regeneration was severe were significantly higher than those in patients in whom irregular regeneration was mild (p < 0.05). Concerning the relationship between hepatitis virus markers and CS or CVCS, CVCS was significantly higher in those who were hepatitis C virus antibody positive and those who were hepatitis B surface antigen negative (p < 0.01). Using a combination of CS and CVCS, the incidence of HCC, as determined by the Kaplan-Meier method, was significantly higher in patients whose CS was > or = 1.5 and CVCS was > or = 15%, as compared with that in patients whose CS was <1.5 and CVCS was <15% (p < 0.01) and whose CS was > or = 1.5 and CVCS was <15% (p < 0.05). Multivariate analysis of the predictors for HCC using the Cox's proportional hazards model showed a significant correlation between the risk of development of HCC and CVCS, CS and serum alpha-fetoprotein level. CONCLUSIONS: CVCS and CS can be calculated from liver echo patterns and are useful for identifying a high-risk group for HCC.

Alanine Transaminase↗
PubMed2002

A new diagnostic method for chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma based on serum metallothionein, copper, and zinc levels.

Serum metal levels and their ratios are frequently reported to be good signals for diagnosing various diseases. These parameters are not always specific to the disease, however, it is necessary to use other serum parameters for an exact diagnosis. We examined whether the monitoring of these serum parameters such as metallothionein, copper, and zinc levels are useful in diagnosing hepatic disorders. Metallothionein levels of patients with liver cirrhosis and hepatocellular carcinoma were found to be significantly lower than those of patients with chronic hepatitis and those of controls. In contrast, copper levels of the patients with liver cirrhosis and hepatocellular carcinoma were significantly higher than those with chronic hepatitis and controls. Zinc levels of the patients with chronic hepatitis and hepatocellular carcinoma were lower than those of controls. Using these three parameters, we are introducing a new parameter, (Cu/Zn)/MT, by which we can discriminate between patients in the [control+miscellaneous diseases+chronic hepatitis] group and those in the [liver cirrhosis+hepatocellular carcinomal group. The new parameter does not, however, allow us to clearly distinguish between the liver cirrhosis and hepatocellular carcinoma groups. Multivariate discriminant analysis was found to be very useful, with combinations of two discriminant functions having been designed to discriminate both between chronic hepatitis and liver cirrhosis and between liver cirrhosis and hepatocellular carcinoma. This method recognizes the differences between hepatic disorder, including chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma groups. On the basis of these results, we propose here that the diagnosis of hepatic disorders should be made based on a combination of three serum levels such as those of metallothionein, copper, and zinc.

Carcinoma, Hepatocellular↗