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Biomedical subjects

Y Hatanaka

Publications and source records attributed to Y Hatanaka.

At least 91 records · Page 5Linked to original sources
PubMed1995

Adnexal masses: accuracy of characterization with transvaginal US and precontrast and postcontrast MR imaging.

PURPOSE: To determine the accuracy of transvaginal ultrasound (TVUS) and of precontrast and contrast material-enhanced magnetic resonance (MR) imaging in the differentiation of adnexal masses. MATERIALS AND METHODS: Five blinded readers analyzed images of 80 masses in 72 patients. MR and TVUS images were interpreted in separate sessions. Findings were confirmed at surgery or laparoscopy. RESULTS: Higher diagnostic accuracy was attained with MR imaging in mature cystic teratomas and endometriomas. However, better accuracy was achieved with contrast-enhanced MR imaging and TVUS in simple cysts, cystadenomas, and malignant tumors because internal details could be visualized. Receiver operating characteristic study indicated that observer confidence was significantly higher with contrast-enhanced MR imaging than with precontrast MR imaging (P = .011) or TVUS (P = .002) in the differentiation of benign and malignant masses. CONCLUSION: Contrast-enhanced MR imaging is superior to precontrast MR and TVUS imaging in the characterization and differentiation of adnexal masses.

Adnexal Diseases↗
PubMed1995

Hepatocellular carcinoma in cirrhotic livers: detection with unenhanced and iron oxide-enhanced MR imaging.

PURPOSE: To evaluate diagnostic accuracy with unenhanced and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for detection of hepatocellular carcinoma (HCC) in cirrhotic livers. MATERIALS AND METHODS: Fifteen patients with 26 histologically proved HCCs associated with liver cirrhosis underwent imaging with T1-, T2-, and proton-density-weighted spin-echo (SE) and fast low-angle shot (FLASH) sequences. Lesion-to-liver contrast-to-noise ratios were measured in all sequences. Diagnostic performance of the imaging techniques was assessed by using receiver operating characteristic analysis. RESULTS: Enhanced SE and FLASH sequences were significantly more accurate (P < .005) for the detection of small HCCs. Among the unenhanced pulse sequences, the accuracy of tumor localization was highest with the T2-weighted SE sequences; however, 25% of the lesions were located incorrectly. Compared with unenhanced images, lesions were correctly located more often when SPIO-enhanced SE and FLASH sequences were used. CONCLUSION: SPIO-enhanced MR imaging with proton-density-weighted or FLASH sequences was more accurate in the detection of small HCCs in cirrhotic livers.

Biopsy↗
PubMed1995

Unresectable hepatocellular carcinoma: analysis of prognostic factors in transcatheter management.

PURPOSE: To evaluate the effect of transcatheter management of hepatocellular carcinoma (HCC) on survival. MATERIALS AND METHODS: A prospective trial of transcatheter arterial embolization (TAE) was performed in patients with unresectable HCC. Three hundred twenty-two patients (265 men, 57 women; age range, 30-83 years) underwent TAE alone: 60 patients underwent TAE with gelatin sponge (GS) that contained anticancer agents (protocol 1); 78, TAE with GS and iodized oil mixed with anticancer agents (protocol 2); and 159, TAE with iodized oil with anticancer agents (protocol 3). A Cox proportional hazard model was used to analyze prognostic factors. RESULTS: In the randomized group (n = 272), survival rates for protocols 1, 2, and 3 were 80.4%, 86.3%, and 65.9%, respectively, at 1 year. Findings of analysis of prognostic factors showed that extrahepatic metastases, ascites, tumor extension, and icterus were the important factors. CONCLUSION: TAE with GS was superior to TAE without GS. Patient characteristics were important factors for survival.

Adult↗
PubMed1995

US-guided liver biopsy: predicting the effect of interventional treatment of hepatocellular carcinoma.

PURPOSE: To analyze the results of ultrasound (US)-guided biopsy as a predictor of the outcome of interventional treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: US-guided biopsy was performed in 125 lesions in 102 high-risk patients, before transcatheter arterial embolization (TAE) (82 lesions) or before percutaneous ethanol injection (PEI) therapy (25 lesions, including 14 lesions previously treated with TAE). Pathologic results were correlated with treatment effects. RESULTS: Results of biopsy confirmed 107 HCCs, which were classified as early (n = 17), frank (n = 67), sclerosing (n = 12), or poorly differentiated or undifferentiated (n = 11). Hypervascularity was observed in most frank HCCs, with a good response to TAE. Tumor vascularity in early or sclerosing HCCs was slight and did not respond to TAE. Sclerosing and poorly differentiated or undifferentiated HCCs enlarged after treatment, whereas early HCCs did not. Early HCCs were treated successfully with PEI therapy; sclerosing HCCs responded poorly to PEI therapy. CONCLUSION: Evaluation of histologic subtype of HCC by means of US-guided biopsy is essential, because subtype may affect treatment planning.

Adult↗
PubMed1995

Insulin resistance associated with decreased levels of insulin-receptor messenger ribonucleic acid: evidence of a de novo mutation in the maternal allele.

Mutations in the insulin receptor gene may lead to insulin resistance and diabetes mellitus in some patients. We have studied an insulin-resistant patient with leprechaunism. Insulin binding to the patient's fibroblasts was markedly decreased. Determination of the nucleotide sequence of the patient's insulin receptor gene revealed heterozygosity for a 2-basepair deletion in exon 15. If the premessenger ribonucleic acid (pre-mRNA) is spliced normally, it causes a replacement of codon 970 in the beta-subunit with a premature chain termination codon, thereby deleting most of the intracellular domain of the receptor. The mRNA transcribed from the allele with a 2-base-pair deletion is likely to be unstable because mRNA transcripts from this allele could not be detected by complementary DNA sequencing. Northern blot analysis showed that the patient's insulin receptor mRNA was decreased by 90% compared with that of a control subject, thus suggesting that the patient is a compound heterozygote for two mutations that decrease levels of insulin receptor mRNA. This deletion mutation in exon 15 seems to be a de novo mutation, because it was not detected in either parent. Investigation of the inheritance of a silent sequence polymorphism in exon 17 provided that the deletion occurred in the maternal allele. Furthermore, linkage analysis suggests that the second mutation is derived from the patient's father, although we could not directly identify it by sequencing the coding region of the insulin receptor gene. Therefore, it is possible that this mutation is present in a regulatory domain of the insulin receptor gene, acting in cis-dominant fashion to reduce the levels of insulin receptor mRNA. Analyses of the hypervariable region in the myoglobin and pMCT118 loci were consistent with the assumption that the father and mother studied here are indeed the biological parents of the diseased patient. We hereby conclude that the patient is a compound heterozygote for two mutant alleles, both of which are responsible for the reduced levels of insulin receptor mRNA and insulin binding.

Adult↗
PubMed1995

Studies on metabolites of mycoparasitic fungi. IV. Minor peptaibols of Trichoderma koningii.

Three minor peptaibols, trichokonins (TKs)-Ia, Ib, and IX, were obtained from the culture broth of Trichoderma koningii Oudemans. Primary structures of these peptaibols were elucidated by ion-spray ionization mass spectrometry (ISI-MS) including the collision-induced dissociation (CID) technique together with two-dimensional nuclear Overhauser enhancement spectroscopy (NOESY).

Alamethicin↗
PubMed1995

Magnetic resonance characteristics of intrapelvic haematomas.

Although haematomas in the female pelvis are not rare, their magnetic resonance (MR) appearance has not been well characterized. Accordingly, we analysed the MR appearances of various stages of haematomas in the female pelvis. A retrospective analysis of 35 haematomas in 28 patients sequentially imaged with a 1.5 T MR unit was performed. The time interval between the insult and MR imaging was determined and the appearances of the haematoma were evaluated. The results were compared with those in the central nervous system. The evolution of haematomas in the pelvis appeared similar to that of haematomas in the brain, and four stages (acute, early subacute, late subacute and chronic) were identified according to the signal intensity pattern on T1 and T2 weighted images. Pelvic haematomas differed from intracranial haematomas in the following features: (1) The speed of evolving pelvic haematomas was gradual. (2) In the centre of acute haematomas, slightly hyperintense areas were seen on both sequences, suggesting residual oxyhaemoglobin. (3) Haematomas evaluated in the early subacute stage had complex appearances. (4) In older haematomas, central intermediate signal intensity areas, presumably due to diamagnetic hemichromes, became predominant on T1 weighted images. In conclusion, although the evolution of a pelvic haematoma is similar to that of a brain haematoma, its speed is gradual and MR appearances are somewhat different due to environmental differences.

Adolescent↗
PubMed1995

Binding of pig sperm receptor in the zona pellucida to the boar sperm acrosome.

Pig zona pellucida (ZP) contains three families of glycoproteins: PZP2, PZP3 alpha and PZP3 beta. PZP3 alpha mediates the binding of the ZP to spermatozoa. In this study, the binding site of pig ZP on boar spermatozoa and the zona-binding proteins of boar spermatozoa were studied using chemically modified zona glycoproteins or anti-pig ZP antiserum. Endo-beta-galactosidase-digested PZP3 alpha (E beta G-PZP3 alpha), which is deficient in sulfated N-acetylpolyactosamine, as well as solubilized ZP, bound to the acrosomal region of acrosome-damaged or partially acrosome-reacted spermatozoa. However, they did not bind to acrosome-intact or fully acrosome-reacted spermatozoa. Solubilized ZP did bind to the acrosomal cap released upon acrosome reaction. In western blot analyses, E beta G-PZP3 alpha bound to the sperm proteins with molecular masses similar to proacrosin-acrosin and the binding was inhibited by fucoidan and anti-pig acrosin antiserum. These results suggest that the binding site of solubilized pig ZP and E beta G-PZP3 alpha on spermatozoa is located mainly in the acrosomal matrix and on the membranous compartments in the acrosome and suggest that E beta G-PZP3 alpha binds to proacrosin-acrosin. The binding of E beta G-PZP3 alpha to proacrosin-acrosin may be involved in the binding of the ZP to the acrosome of partially acrosome-reacted spermatozoa.

Acrosome↗
PubMed1994

Intracortical regionality represented by specific transcription for a novel protein, latexin.

The monoclonal antibody (mAb) PC3.1 recognizes a subset of neurons distributed in the infragranular layers of the lateral neocortex of the rat. Immunoaffinity chromatography with mAb PC3.1 showed that this antibody specifically binds a peptide epitope on a 29 kDa protein named latexin. To study the molecular details of the protein, we isolated four independent cDNA clones for latexin from cDNA libraries of the rat cerebral cortex and whole brain using the amino acid sequences of latexin fragments. Analysis of these cDNA clones showed that the predicted primary structure of latexin consists of 223 amino acids, and has no strict homology to any sequences so far known. Western and Northern blots demonstrated that the latexin and its mRNA were expressed predominantly in neural tissues with some expression in non-neural tissues. The gene that encodes latexin in the rat appeared to have homologues in other mammalian species and in the chick. In situ hybridization showed that latexin mRNA is synthesized in a subset of neurons in the lateral but not the dorsal neocortex, and that the distribution profile of these neurons is quite similar to that of neurons expressing latexin. These results indicate that latexin is a novel class of neuronal protein which represents intracortical regionality, and suggest that the regional specification of the neocortex involves selective parcellation of neurons which express a particular gene.

Amino Acid Sequence↗
PubMed1994

A novel biotinylated heterobifunctional cross-linking reagent bearing an aromatic diazirine.

The synthesis of a p-[(3-trifluoromethyl)diazirine-3-yl]benzoic acid derivative is described as a new carbene generating heterobifunctional cross-linking reagent. The cross-linker carries a biotin moiety in order to make use of avidin-biotin technology for specific manipulation of cross-linked components. To evaluate the ability of this reagent, the inter-subunit cross-linking of egg-white avidin tetramer was investigated. As a typical application of avidin-biotin technology for cross-linking experiments, a chemiluminescent detection method was examined to identify photobiotinylated components. A cross-linked dimeric product with an apparent molecular mass of 38 kDa was clearly visualized by the combined use of a horseradish peroxidase-streptavidin conjugate and a luminol-based chemiluminescent system.

Avidin↗
PubMed1994

pH-sensitive dissociation and association of beta-N-acetylhexosaminidase from boar sperm acrosome.

beta-N-Acetylhexosaminidase (beta-Hex, EC, 3.2.1.52) was released from cauda epididymal boar sperm by treatment with ionophore A23187, indicating that this enzyme is localized in the acrosome. beta-Hex was extracted on a large scale, with 2% acetic acid containing 0.2% Brij 35, from washed ejaculated sperm. By gel filtration chromatography, beta-Hex was separated into a high-molecular-weight fraction (beta-Hex I) and a low-molecular-weight fraction (beta-Hex I). beta-Hex I, which is predominant under acidic conditions (pH 6.5), dissociated into beta-Hex II under alkaline conditions (pH 7.4). beta-Hex II, converted from beta-Hex I, associated again to form beta-Hex I under acidic conditions. By sequential chromatography on ion-exchange, lectin, gel filtration, and ion-exchange HPLC columns, beta-Hex I and II were purified 1200-fold and 4000-fold, respectively, with a combined recovery of 23% as measured with synthetic substrate. An inhibitor of beta-Hex, O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino N-phenyl-carbamate (PUGNAC), reduced the in vitro fertilization rate in porcine cumulus-enclosed eggs, but barely changed the rate when cumulus-free eggs were used. beta-Hex I was shown to possess cumulus dispersion activity, suggesting that beta-Hex plays a role in the passing by sperm through cumulus cells before they bind to the zona pellucida.

Acetylglucosamine↗
PubMed1994

Value of phase-shift gradient-echo MR imaging in the differentiation of pelvic lesions with high signal intensity at T1-weighted imaging.

PURPOSE: To assess the value of phase-shift gradient-echo magnetic resonance (MR) imaging with the fast low-angle shot (FLASH) technique in the differentiation of hemorrhagic tumors and teratomas. MATERIALS AND METHODS: T1- and T2-weighted spin-echo imaging and phase-shift MR imaging were performed in 60 patients. On T1-weighted images, the signal intensity of lesions was compared with that of intraperitoneal fat. Findings at MR imaging were compared with the surgical findings. The diagnostic performance of each pulse sequence was analyzed with receiver operating characteristic curves. RESULTS: Sixty high-signal-intensity lesions were identified in 45 patients at T1-weighted imaging. Hemorrhagic lesions and teratomas had similar signal intensities on both T1- and T2-weighted images. Lesions were detected more decisively with FLASH imaging than with T1- and T2-weighted imaging. CONCLUSIONS: Phase-shift gradient-echo imaging is a readily available method for the differential diagnosis of lesions with high signal intensity at T1-weighted MR imaging.

Adolescent↗
PubMed1994

Differential diagnosis of focal liver lesions: role of spin-echo and contrast-enhanced dynamic MR imaging.

PURPOSE: To evaluate the role of spin-echo (SE) and contrast material-enhanced dynamic magnetic resonance (MR) imaging in the differential diagnosis of focal liver lesions. MATERIALS AND METHODS: Conventional T1- and T2-weighted SE and fast low-angle shot dynamic MR imaging were performed in 300 focal liver lesions on a 1.5-T MR imager. Findings at both SE and dynamic imaging were analyzed by means of univariate and multivariate analysis. RESULTS: Although considerable overlap existed, signal intensity on T2-weighted images, tumor margin, and internal architecture were significant factors for SE imaging. For dynamic imaging, the hemodynamics and pattern of enhancement were significant factors. A logistic regression analysis revealed 86% of lesions were correctly categorized with these parameters. CONCLUSION: A specific diagnosis of liver lesions can be obtained in most cases by combining parameters obtained from SE and dynamic MR images.

Contrast Media↗
PubMed1994

Mature cystic teratomas of the ovary without fat in the cystic cavity: MR features in 12 cases.

OBJECTIVE: The diagnosis of mature cystic teratoma may be overlooked in the small number of cases that do not contain fat in the lumen of the cyst. The purpose of this study was to evaluate the MR appearance of mature cystic teratomas containing little or no fat and to determine the value of gradient-echo MR imaging for detection of small amounts of fat. MATERIALS AND METHODS: In a review of pathologic specimens of 78 mature cystic teratomas, we found 12 tumors without fatty fluid (sebum) in their cystic cavity. Histologically, a small amount of fat was present in the wall of the cyst in each case. We retrospectively reviewed MR images of these tumors. In seven tumors with small amounts of hyperintense tissue on T1-weighted MR images, opposed-phase and in-phase gradient-echo MR images were obtained in order to verify the presence of fat. RESULTS: All 12 lesions were hypointense on T1-weighted MR images and markedly hyperintense on T2-weighted images, indicating that the cystic cavity contained aqueous fluid. Fatty tissue was not identified in the lumen or wall of the cyst on MR images in five of the 12 tumors. In seven tumors, MR images showed small hyperintense areas in the walls of the cysts. These hyperintense signals were canceled on opposed-phase gradient-echo images. Characteristic MR findings for mature cystic teratoma, such as reversed chemical-shift artifact, gravity-dependent layering, or dermoid plug, were not observed in any of the lesions. CONCLUSION: MR images in some cases of mature cystic teratomas may show aqueous fluid within the lumen of the cyst. In such cases, detection of fat in the cyst wall, especially with gradient-echo MR imaging, may help to establish the diagnosis.

Adipose Tissue↗
PubMed1993

[Infusion therapy for acute superior mesenteric artery occlusion].

We performed transcatheter fibrolytic therapy using a coaxial microcatheter in two cases of acute superior mesenteric artery occlusion in the early stage. The tip of the microcatheter was introduced into the clot of the superior mesenteric artery. Urokinase was infused at a rate of 10,000 IU/min. The clots dissolved immediately after the infusion of 240,000 IU and 480,000 IU, respectively, without any complications. This infusion technique is promising for the treatment of acute superior mesenteric artery occlusion.

Aged↗
PubMed1993

Clinico-pathological studies on a transitional type between extrahepatic biliary atresia and paucity of the interlobular bile ducts.

Among the neonatal and infantile cases of obstructive jaundice seen at Niigata and Yamagata University Hospitals between 1976 and 1990, extrahepatic bile ducts were visualized in 19 cases by either preoperative endoscopic retrograde cholangiopancreaticography (ERCP) or intraoperative cholangiography. Neonatal hepatitis was diagnosed in 3 of these cases by clear images of the bile duct system extending from the common bile duct to the intrahepatic bile duct. In 7 cases, the common bile duct was able to be seen, while the common hepatic duct was only slightly visualized. Four of these 7 cases were consistent with paucity of the interlobular bile ducts (PILBD) based on hepatic histology, while the remaining 3 showed fibrosis, bile ductular proliferation, and many bile plugs in the bile ductuli of the portal areas, concurrent with histological changes in extrahepatic biliary atresia (EHBA), not PILBD. In 9 cases, only the common bile duct was visualized while the common hepatic duct was not seen, 7 of these 9 cases being consistent with type III-a1 EHBA. In 2 cases, neither fibrosis nor proliferation of the bile ductuli was observed in the portal areas, and portal areas without any bile ductuli were also seen, in accordance with findings for PILBD. Three cases which showed similar hepatic histological findings to EHBA despite the presence of patent extrahepatic bile ducts, and 2 cases which had obstructed extrahepatic bile ducts and hepatic histological findings similar to PILBD, were thought to be of a transitional type between EHBA and PILBD.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile Duct Diseases↗