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Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 397 records · Page 22Linked to original sources
PubMed1997

Doppler echocardiographic evaluation of ventricular diastolic filling in fetuses with ductal constriction.

To assess ventricular diastolic filling in fetuses with constriction of ducts arterious, 43 fetuses of pregnant women receiving indomethacin (100 to 150 mg/day) were examined with Doppler echocardiography. Ductal constriction occurred in 21 fetuses, defined as maximal systolic velocity > 140 cm/s and diastolic flow velocity > 30 cm/s. The variables measured to assess diastolic function were peak velocity during early diastole (peak E wave), peak velocity during atrial contraction (peak A wave), and the velocity ratio (peak E/A ratio); these were compared to maximal ductal flow velocity during systole and diastole. The mitral peak E wave, peak A wave, and peak E/A ratio in fetuses with ductal constriction showed no significant difference from those in fetuses without ductal constriction. In fetuses with ductal constriction, the tricuspid A wave increased significantly without changes in the peak E wave (57 +/- 9 vs 50 +/- 6 cm/s, p < 0.01) and the peak E/A ratio was significantly lower than in fetuses without ductal constriction (0.57 +/- 0.10 vs 0.65 +/- 0.08, p < 0.05). In 9 fetuses with ductal constriction, we compared the Doppler tricuspid E wave, A wave, and E/A ratio during indomethacin administration with those after withdrawal of the drug for a mean of 24 hours. Both systolic and diastolic ductal flow velocities in the fetuses returned to normal range after discontinuation of indomethacin. The tricuspid peak A wave decreased (59 +/- 9 vs 50 +/- 11 cm/s) and the E/ A ratio increased significantly (0.56 +/- 0.07 vs 0.69 +/- 0.07) (both p < 0.01) without any significant change in peak E wave after discontinuation of indomethacin. This study suggests that ductal constriction influences Doppler patterns of right ventricular diastolic filling. These changes could be related to the increased afterload presented to the right ventricle which might affect diastolic function.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Induction of cyclin-dependent kinase inhibitor, p21WAF1, by treatment with 3,4-dihydro-6-[4-(3,4)-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinoline (vesnarinone) in a human salivary cancer cell line with mutant p53 gene.

It has been found by PCR-SSCP analysis and direct DNA sequencing that a human salivary adenosquamous carcinoma-forming cell line, TYS, has a mutant p53 gene at codon 281Asp-->His. When TYS cells were treated with a differentiation-inducing agent, vesnarinone, cellular proliferation was significantly inhibited on the basis of MTT assay. In addition, it has been found by Northern blotting and/or immunoblotting that expression of p21WAF1 and transforming growth factor-beta (TGF-beta) is up-regulated by treating TYS cells with vesnarinone. TGF-beta 1 alone also induced p21WAF1 expression in TYS cells. Moreover, it has been shown by ELISA that the treatment of TYS cells with vesnarinone results in the enhanced generation of latent TGF-beta 1. The expression of TGF-beta receptor (T beta R), including T beta R-I, T beta R-II and T beta R-III, on TYS cells was detected by affinity cross-linking using 125I-TGF-beta 1 and addition of active TGF-beta 1 into serum-free culture medium inhibited the growth of TYS cells in a concentration-dependent manner. These findings suggest that vesnarinone might directly induce expression of p21WAF1 gene in TYS cells, the product of which may be associated with the inhibition of cell growth and induce differentiation.

Antineoplastic Agents↗
PubMed1997

Gestational age- and growth-related alterations in fetal right and left ventricular diastolic filling patterns.

To evaluate the effects of gestational age on left and right ventricular diastolic filling in human fetuses, we retrospectively reviewed the diastolic flow velocity patterns through mitral and tricuspid valves in 307 normal fetuses aged 17 to 39 weeks' gestation. The subjects were divided into 3 age groups; 17 to 24 weeks, 25 to 31 weeks, and 32 to 39 weeks. The variables measured were peak flow velocities of early diastole (peak E wave), of atrial contraction (peak A wave), and the velocity ratio (peak E/A ratio). As a whole, the transmitral peak E wave and peak E/A ratio correlated with age using a second-order polynomial curve fit. The strength of the linear correlation between age and transmitral peak E wave and peak E/A ratio and the slope of the relation were greater in the group aged 32 to 39 weeks than in group aged 25 to 31 weeks. Similar temporal change was observed in the relation between age, transtricuspid peak E wave, and peak E/A ratio. The peak A wave for both atrioventricular valves showed little change with gestational age. Contrary to the accepted concept that fetal peak E wave and peak E/A ratio increases linearly with aging, this study shows that early diastolic filling increases mainly after 25 weeks' gestation. We speculate that the maturational changes in ventricular properties in human fetuses accelerate after midgestation.

Atrial Function↗
PubMed1997

Possible contribution of active MMP2 to lymph-node metastasis and secreted cathepsin L to bone invasion of newly established human oral-squamous-cancer cell lines.

We have established human oral-squamous-cancer cell lines, BHY and HN, derived from non-metastatic cancer and metastatic cancer respectively. We examined the expression of matrix-degrading enzymes and their inhibitors in these cell lines. Both cell lines expressed pro-matrix metalloproteinase (MMP)1, proMMP2, proMMP9, membrane-type MMP and urokinase-type plasminogen activator. In addition to these enzymes, BHY cells secreted proMMP7 and procathepsin L, while HN cells secreted a large amount of active MMP2. BHY cells secreted a tissue inhibitor of matrix metalloproteinase, TIMP2, but only a trace level of TIMP1. Contrary to BHY cells, HN cells secreted TIMP1, but only a trace level of TIMP2. When we inoculated these cells into the masseter muscle of nude mice, both types of cell formed solid tumors, whose microscopic appearance was identical to that of the original tumors. BHY tumors were highly differentiated squamous-cell carcinomas, and invasive to the masseter muscle and the mandibular bone. Despite their local aggressiveness, BHY tumors did not metastasize to any distant organs. HN tumors were poorly differentiated squamous-cell carcinomas, weakly invasive to the muscle, but not to the mandibular bone. However, HN tumors frequently metastasized to cervical lymph nodes. These results suggest that the net activity of MMP2 (active MMP2/TIMP2) and cathepsin L secreted from cancer cells may contribute respectively to lymph-node metastasis and to bone invasion by oral cancer cells.

Animals↗
PubMed1997

Identification and estimation of microcystins in freshwater mussels.

Accumulation of microcystins mainly produced by cyanobacteria Microcystis was investigated for freshwater mussels and fishes collected from a lake where heavy blooms of Microcystis occurred every year. The identification of microcystins was performed by HPLC equipped with a frit FAB mass spectrometer. Microcystins LR and RR were identified in the mussels Unio douglasiae and Anadonta woodiana, whereas no microcystin was identified by the present method in fishes, such as Cyprinus carpio, Carassius carassius, and Hypomesius transpacificus.

Animals↗
PubMed1997

In situ nucleic acid hybridization of pyruvate dehydrogenase complex-E2 in primary biliary cirrhosis: pyruvate dehydrogenase complex-E2 messenger RNA is expressed in hepatocytes but not in biliary epithelium.

Pyruvate dehydrogenase-E2, or a cross-reactive molecule, has been shown by a variety of immunohistochemical methods to be present in increased amounts in biliary epithelial cells (BEC) in primary biliary cirrhosis (PBC). In this study, to further understand the nature of the immunoreactive molecule in BEC, we examined the expression of pyruvate dehydrogenase complex-E2 (PDC-E2) messenger RNA (mRNA) and PDC-E2 protein in sections of livers from patients and controls to help identify the molecule found in BEC. We performed in situ hybridization using an antisense probe against the major epitope of PDC-E2. The data were very striking and suggested that there was no increased production of PDC-E2 in BEC. For example, in livers from patients with PBC, PDC-E2 mRNA was found in periportal hepatocytes in 16 of 17 cases (94%). In contrast, interlobular bile ducts and septal bile ducts had detectable levels of PDC-E2 mRNA in only 1 of 17 (6%) and 3 of 8 (38%) cases, respectively. Interestingly, proliferating bile ductules contained detectable levels of mRNA in 12 of 15 cases (80%). In control liver, periportal hepatocytes were positive in 15 of 17 cases (88%). Interlobular bile ducts, septal bile ducts, and proliferating bile ductules expressed mRNA signals in 4 of 17 (24%), 2 of 10 (20%), and 14 of 16 (88%), respectively. When formalin-fixed, paraffin-embedded sections were examined by immunohistochemical staining with anti-PDC-E2 monoclonal antibody (mAb) C355.1, the interlobular bile ducts showed typical aberrant apical staining in all 10 PBC cases, but 0 of 9 liver controls. Periportal hepatocytes, proliferating bile ductules and infiltrating mononuclear cells stained with C355.1 but in a characteristic mitochondrial staining pattern. The presence of a PDC-E2-like molecule recognized by C355.1 is not reflected by the expression levels of PDC-E2 mRNA in the BEC of patients with PBC.

Bile Ducts↗
PubMed1997

In situ nucleic acid hybridization of cytokines in primary biliary cirrhosis: predominance of the Th1 subset.

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by destruction of the intrahepatic bile ducts. It is generally believed that cellular immune mechanisms, particularly involving T cells, result in this bile duct damage. The relative strength of Th1 and Th2 responses has recently been proposed to be an important factor in the pathophysiology of various autoimmune diseases. In this study, we have attempted to identify the Th subset balance in PBC, by detection of cytokines specific to the two T-cell subsets, i.e., interferon gamma (IFN-gamma) for Th1 cells and interleukin-4 (IL-4) for Th2 cells. We analyzed IFN-gamma and IL-4 messenger RNA (mRNA) positive cells in liver sections from 18 patients with PBC and 35 disease controls including chronic active hepatitis C, extrahepatic biliary obstruction (EBO), and normal liver, using nonisotopic in situ hybridization and immunohistochemistry. Mononuclear cells expressing IFN-gamma and IL-4 mRNA were aggregated in inflamed portal tracts in PBC livers, but were rarely present in extrahepatic biliary obstruction, alcoholic fibrosis, or normal liver sections. The IFN-gamma and IL-4 mRNA positive cells in PBC livers were detected in significantly higher numbers than in control livers (P < .01). Moreover, IFN-gamma mRNA expression was more commonly detected than IL-4 expression in PBC livers, and the levels of IFN-gamma mRNA expression were highly correlated with the degree of portal inflammatory activity. IFN-gamma mRNA-positive cells were detected primarily around damaged bile ducts that were surrounded by lymphoid aggregates. The data indicate that Th1 cells are the more prominent T-cell subset in the lymphoid infiltrates in PBC.

Actins↗
PubMed1997

Enhanced apoptosis relates to bile duct loss in primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is characterized by an immune-mediated destruction of intrahepatic small bile ducts. Apoptosis, a unique pattern of cell death, has been suggested to be responsible for the biliary destruction in PBC. To address this issue, we attempted to detect the apoptosis of biliary epithelial cells by in situ nick-end labeling and by the expression of apoptosis-related proteins using immunohistochemistry in patients with various hepatobiliary diseases, including PBC. The data was noteworthy for several reasons. First, apoptosis was occasionally detected on biliary cells in all liver specimens; however, the positive rate was high in PBC and relatively low in other livers. Strong expression of CD95 was frequently observed in the epithelial cells of the injured bile ducts of PBC, which accompanied high intensity CD95 ligand-expressing mononuclear cells. Perforin and granzyme B immunoreactivities were occasionally found on the bile ducts in control liver diseases as well as PBC, but granzyme B-positive biliary cells were prominent in PBC. In contrast, Lewis Y expression, as detected using BM-1 antibody, was consistently present in the injured bile ducts of PBC. These data suggest that apoptosis, via the perforin/granzyme B pathway, may be associated with the degrading fraction of cell cycle regulation in the small-sized biliary tree under physiological and pathological liver conditions. Moreover, enhanced apoptosis, mediated by CD95/CD95 ligand interaction, may contribute to the bile duct injury and loss observed in PBC.

Aged↗
PubMed1997

High-performance liquid chromatographic separation of microcystins derivatized with a highly fluorescent dienophile.

Microcystins are potent hepatotoxins produced by cyanobacteria, and are also tumor promoters as well as potent inhibitors of the catalytic subunits of protein phosphatases 1 and 2A. In order to establish a physicochemical method for individual detection and determination of trace amounts of microcystins, we developed a derivatization method for fluorescence (FL) and chemiluminescence (CL) detection, in which a highly fluorescent dienophile, DMEQ-TAD (4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl) ethyl]-1,2,4-triazoline-3,5-dione), was used as the labeling reagent. DMEQ-TAD reacted smoothly with the conjugated diene of the Adda moiety to give 2 stereoisomers of the adducts. As a result of the extensive experiments, the following reaction conditions were optimized for the labeling: sample amount, 10 micrograms; reaction solvent, DMF:acetonitrile (1:1); reaction time, 15 minutes; reaction temperature, 70 degrees C; amount of DMEQ-TAD used relative to that of microcystin, 80 equivalent. The resulting 6 adducts from microcystins-LR, -YR, and -RR can be separated from one another using the following reversed phase HPLC conditions in combination with a clean-up using ODS silica gel: column, Cosmosil 5C18-AR (150 x 4.6 I.D. mm); mobile phase, methanol:0.05M phosphate buffer (pH 3) (1:1); flow rate, 1.0 ml/min; detection, FL lambda ex 370 nm, lambda em 440 nm. The detection limits of the DMEQ-TAD derivatives were estimated to be 100 and 500 pg for LR, and 65 and 2,500 pg for RR using FL and CL detections, respectively; and the detection behavior was different from that of the Dns-Cys derivatives, which were more sensitive to CL than FL.

Bacterial Toxins↗
PubMed1997

Chylothorax in a polysplenia infant with cor triatriatum, pulmonary stenosis and sick sinus syndrome.

An infant with chylothorax and polysplenia is described. Her chylothorax was refractory and related to right-sided heart failure derived from pulmonary stenosis, cor triatriatum, and sick sinus syndrome. In addition to Brock operation and cardiac pacing, thoracic duct ligation was performed, but it resulted in an only transient amelioration of the chylothorax. Eventually, the chylothorax resolved when total cardiac repair was performed for cor triatriatum. We propose that, in a patient with chylothorax and right-sided heart failure caused by compound cardiac malformations, as in this patient early surgical treatment for the underlying disease of right-sided heart failure should be considered.

Chylothorax↗
PubMed1997

Effects of submucosal administration of endothelin-3 on rat gastric mucosa.

The present study was carried out to examine the effects of submucosal administration of endothelin on gastric mucosal integrity in rats. Injection of endothelin-3 into the submucosal space of the stomach induced gastric mucosal damage dose-dependently and site-specifically. The gastric injury was localized only at the injected site and the mucosal damage was associated with hemorrhage. Macroscopic and microscopic examinations revealed that mucosal injury had developed 15 min after endothelin application. Submucosal injection of either adrenalin or noradrenalin also induced gastric mucosal damage, but produced multiple gastric mucosal lesions; i.e., the macroscopic appearance of endothelin-induced gastric lesions differed from those produced by catecholamines. The endothelin-induced mucosal lesions were significantly inhibited by pretreatment with either atropine, pirenzepine, or ranitidine; or by vagotomy. In addition, NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, significantly enhanced the formation of gastric mucosal lesions. Thus, it appears that nitric oxide synthesis, possibly induced by endothelin, may play a role as an antiulcer mechanism in endothelin-induced gastric mucosal damage. Vagotomy and anti-cholinergic or anti-secretory treatment significantly attenuated the severity of the mucosal lesions, suggesting that vagal cholinergic pathways and acid secretion may influence the development of the gastric mucosal damage induced by endothelin-3. These results suggest that endothelin-3 may play an important role in the development of gastric ulceration; the submucosal application of endothelin-3 in the gastric mucosa may be a useful experimental model for investigating acute gastric mucosal ulceration.

Animals↗
PubMed1997

Expression of pancreatic digestive enzymes in normal and pathologic epithelial cells of the human gastrointestinal system.

Pancreatic digestive enzymes have rarely been reported in human nonpancreatic organs. We examined their expression in the epithelial cells of the nonpancreatic gastrointestinal organs, looking for pancreatic alpha-amylase, trypsin, chymotrypsin and pancreatic lipase. Western blotting, enzyme assay and pancreatic alpha-amylase mRNA were also used in selected specimens. In normal tissues, immunoreactivity of one or more of these enzymes was frequently noted in cells of the salivary glands, stomach, duodenum, large pancreatic ducts, extrahepatic bile ducts and gall bladder. The epithelium of the normal oesophagus, small intestine and colon were consistently negative for these enzymes. In pathologic tissues, immunoreactivity for one or more enzymes was present in epithelial cells of pleomorphic adenomas of the salivary glands, oesophageal squamous cell carcinoma, gastric adenoma and adenocarcinoma, pancreatic adenocarcinoma, cholecystitis, adenocarcinoma of the gall bladder and extrahepatic bile duct, and colon adenoma and adenocarcinoma. Western blotting showed a specific band of each enzyme in some specimens of normal stomach. In situ hybridization for pancreatic alpha-amylase mRNA showed specific signals in the normal stomach, but not in the normal colon. Reverse transcriptase polymerase chain reaction analysis for pancreatic alpha-amylase mRNA revealed specific signals in the normal stomach. Enzyme assay revealed that the stomach and gall bladder showed these activities. The data suggest that pancreatic digestive enzymes are produced by several epithelial cell types of the nonpancreatic gastrointestinal organs, that the organs positive for pancreatic enzyme have a common cell lineage, and that neoplasms continue to express or neoexpress these enzymes after neoplastic transformation.

Adult↗
PubMed1997

Genetic analysis of a clinical isolate of human cytomegalovirus exhibiting resistance against both ganciclovir and cidofovir.

Both ganciclovir-sensitive and -resistant human cytomegaloviruses (HCMV) were isolated from a patient with aplastic anemia complicated with CMV retinitis and encephalitis. Ganciclovir-resistant clinical isolate, 93-1R, also showed cross-resistance against (s)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine (cidofovir). Molecular analysis of plaque-cloned strains revealed that a single nucleotide substitution at 2160 (C to T) resulted in amino acid substitution at codon 501 from leucine to phenylalanine in the DNA polymerase gene. This mutation at codon 501 was easily identified by means of AluI digestion of the selected PCR product. The same mutation existed in the DNA fragment amplified from the patient's brain, suggesting that cross-resistant mutant 93-1R caused encephalitis. Furthermore, ganciclovir-resistant 93-1R-3 replicated much faster and was released more efficiently into the culture medium than ganciclovir-sensitive 91-7S-1.

Antiviral Agents↗
PubMed1997

Cancellation of motion artifact in MRI due to 2D rigid translational motion.

A new algorithm for cancelling MRI artifact due to translational motion in the image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is proposed. In the previous approach, the motions in the readout(x-) direction and the phase encoding(y-) direction are estimated simultaneously. However, the feature of the each x- and y-directional motion is different. Based on the analysis of their features, each x- and y-directional motion is cancelled by different algorithms in two steps. First, we notice that the x-directional motion corresponds to a shift of the x-directional spectrum of the MRI signal, so the x-directional motion can be cancelled by shifting the spectrum in inverse direction. Next, the y-directional motion is cancelled using a new constraint, with which the motion component and the true image component can be separated. The algorithm is shown to be effective by simulations.

Algorithms↗
PubMed1997

Apoptotic cell death in atherosclerotic plaques of hyperlipidemic knockout mice.

In an attempt to understand the roles of apoptosis in the development of atherosclerosis, we classified lesions developed in the aortas of apo E- and LDL receptor-deficient mice, murine models of atherosclerosis, and determined frequency, spatial distribution and cell types of apoptotic cells in each lesion. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and nuclear staining with propidium iodide were used to demonstrate apoptotic cells. Mean frequencies of TUNEL-positive cells were as follows: 0%, in Type I, 0.3% in Type II, 0.05% in Type III, 0.06% in Type IV and 0.06% in Type V lesions. Most of the TUNEL-positive cells were filled with fat and distributed in close proximity to lipid pools. The TUNEL-positive cells in the intimal side of the lipid cores were macrophages, while some of those in the adventitial side were smooth muscle cells. In conclusion, apoptosis is involved in the active turn-over of foam cells of both macrophage- and smooth muscle cell-lineage especially in the early atherosclerotic lesions of the hyperlipidemic mice.

Age Factors↗
PubMed1997

Hepatic necrosis in aged mice by oral administration of microcystin-LR.

Aged mice (32 weeks) were orally administered microcystin-LR at 500 micrograms/kg, and injuries of the liver were estimated by microscopy 2 hr after treatment. Sixty-two per cent of aged mice proved to be sensitive to microcystin-LR, whereas such changes in the liver were not found in young mice (5 weeks). Uptake of the toxin into the liver was confirmed by high-performance liquid chromatography and frit-fast atom bombardment liquid chromatograph/mass spectrometry after clean-up with an immunoaffinity column. To verify the difference in sensitivity to microcystin-LR between aged and young mice, non-treated mice were examined, and among them aged mice were confirmed to have a rough surface of the stomach and small intestinal mucosa. These results suggested that the hepatotoxicity by oral administration of microcystin-LR is deeply related to aging, and particularly to conditions in the small intestine such as the permeability of capillaries in the villi.

Administration, Oral↗
PubMed1997

Stability of microcystins from cyanobacteria--IV. Effect of chlorination on decomposition.

Microcystins, the cyclic heptapeptide toxins produced by cyanobacteria such as Microcystis, show tumor-promoting activity through inhibition of protein phosphatases 1 and 2A. They potentially threaten human health, and are increasing the world-wide interest in the health risk associated with cyanobacterial toxins. In this study, the effect of chlorination on the decomposition of microcystins-LR and -RR was examined. The toxins were easily decomposed by chlorination with sodium hypochlorite, and the decomposition depended on the free chlorine dose. In this operation, many reaction products were formed, one of which was determined to be dihydroxymicrocystin formed through the chloronium ion at the conjugated diene of Adda [3-amino-9-methoxy-10-phenyl-2,6,8-trimethyl-deca-4(E), 6(E)-dienoic acid], followed by hydrolysis. Other products may be its stereoisomers and/or regioismers. No noxious products were detected from the chlorination process of microcystin-LR. Although these results suggested that chlorination at an adequate chlorine dose is very effective for the removal of microcystin in raw water, preoxidation of the cell itself with chlorine must be avoided, because it frequently causes toxin release from algae and produce trihalomethanes during water treatment.

Animals↗