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Biomedical subjects

K Hirata

Publications and source records attributed to K Hirata.

At least 271 records · Page 15Linked to original sources
PubMed1999

The 301 to 314 amino acid residue of beta-tubulin is not a target epitope for serum IgM antibodies in chronic inflammatory demyelinating polyneuropathy.

Connolly et al. [Neurology 48 (1997) 243] reported that IgM M-proteins from three patients selectively binds to an epitope on beta-tubulin that consists of amino acids 301 to 314. We therefore investigated whether these 14 amino acid residues beta301-314 are the target epitope for serum IgMs in sera from 67 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 50 with Guillain-Barré syndrome, 50 with motor neuron diseases, and 50 normal controls. IgM anti-beta301-314 antibodies were not restricted to nor were selectively associated with CIDP. We conclude that beta301-314 is not a target epitope for serum IgMs in CIDP.

Autoantibodies↗
PubMed1999

Substituted 7H-pyrido[4,3-c]carbazoles with potent anti-HIV activity.

Several substituted 7H-pyrido[4,3-c]carbazoles were synthesized from the natural product mukonal and tested for inhibition of HIV replication in H9 lymphocytes. 5-Methoxy-7-methyl-7H-pyrido[4,3-c]carbazole (7) had an EC50 value of 0.0054 microgram/mL and the highest therapeutic index (TI = 503) in the series.

Anti-HIV Agents↗
PubMed1999

L-selectin and its ligands mediate infiltration of mononuclear cells into kidney interstitium after ureteric obstruction.

It was previously reported that the L-selectin ligands detected by a rat L-selectin and human IgG chimeric molecule (rLEC-IgG) are expressed in the distal tubules of the kidney, where no leukocyte traffic is seen under physiological conditions. In the present study, the role of L-selectin ligands in leukocyte infiltration into the kidney interstitium was investigated using a rat ureteric obstruction model. After ligation of the ureter, ligands for L-selectin rapidly disappeared from tubular epithelial cells and were relocated to the interstitium and peritubular capillary walls, where infiltration of monocytes and CD8(+) T cells subsequently occurred. Mononuclear cell infiltration was significantly inhibited by intravenous injection of a neutralizing monoclonal antibody (MAb) against L-selectin, indicating the possible involvement of an L-selectin-mediated pathway. Interestingly, immunohistochemical studies with a MAb against sulphatide showed that the distribution of sulphatide, known to be one of the candidates of L-selectin ligand, was almost indistinguishable from the staining pattern of rLEC-IgG in both normal and ureteric obstructed kidneys, suggesting that sulphatide and/or related molecule(s) relocated to the renal interstitium were recognized by leukocyte L-selectin, leading to interstitial leukocyte infiltration. In line with this notion, intravenous injection of sulphatide markedly inhibited leukocyte infiltration, suggesting that L-selectin-sulphatide interaction may play a pivotal role in interstitial leukocyte infiltration in the kidney following ureteric obstruction.

Animals↗
PubMed1999

Identification of segments VI and VII of the liver based on the ramification patterns of the intrahepatic portal and hepatic veins.

We describe the pattern of intrahepatic vessel ramification in the right posterior hepatic sector in a population of 197 adults. Each specimen was dissected from its visceral (inferior) surface in order to demonstrate variations in the distribution of the portal vein branches to the hepatic segments of the right lobe, especially to segments VI (S6) and VII (S7) as described by Couinaud. We also examine whether three hepatic veins, i.e., the right hepatic vein (RHV), middle hepatic vein (MHV), and the short hepatic vein (SHV), aid the identification of segmental portal branches in the lower posterior sector. Four major patterns of branching of the posterior sectorial trunk of the portal vein system are described. In group A (32.0%) a single posterior trunk formed an arch-like pattern sending multiple branches to S6 and S7 (P6 and P7). We named the multiple branches to the apparent S6 the inferoposterior portal branches. It was difficult to identify which of these branches were equivalent to P6. In group B (27.9%), the posterior sectorial trunk bifurcated to form P6 and P7. In most of the specimens in this group, therefore, we were able clearly to identify both S6 and S7 based on the portal vein system. In group C (6.6%), the trunk trifurcated to form P6, P7, and an intermediate branch, which supplied both segments or a gray zone between them. Group D (33.5%) included variations of the anterior segmental branches, and in specimens of this group, the anteromedial border of the sector was difficult to identify. Notably, the three-dimensional interdigitating topographical relationship of the hepatic veins and the portal branches was not evident in the lower posterior sector, since tributaries of the RHV and the portal branches followed similar courses and paralleled each other in the region and since the territory of the SHV was usually restricted to the superficial parenchyma near the inferior surface. In group A, tributaries of the RHV/SHV (>3 mm in diameter) passed between the inferoposterior portal branches in only 22.2%/14.3% of the specimens. Thus the hepatic veins often did not reveal which of the multiple inferoposterior branches was P6. Moreover, in the subset of Group B in which the segments were identified based on the portal vein ramification, tributaries of the RHV/SHV (>3 mm in diameter) showed the intersegmental interdigitating arrangement in only 32.0%/6.0% of the specimens. In addition, a thick tributary of the MHV, sometimes arising from S6, did not run along, but penetrated the S5/S6 border plane from the lateral to the medial side. Therefore, the three hepatic veins (RHV, SHV, MHV) often did not aid the identification of the liver segments in the region. Consequently, the less than ideal combinations of irregular configurations of the portal and hepatic venous systems suggest that the right posterior segments cannot be conclusively identified anatomically in 30-40% of cases. Other means of identification, such as the conventional proportional manner (the upper and lower halves of the posterior sector roughly correspond to S6 and S7) may be required.

Adult↗
PubMed1999

Usefulness of newly designed pigtail catheter with multiple side holes by reducing incidence of ventricular ectopy.

This study was designed to determine whether a newly designed 5 Fr pigtail catheter of Jet Balance with multiple side holes reduces the incidence of ventricular ectopy during left ventriculography. To examine the catheter movement in vitro, we injected a colored glycerin solution by an injector through 5 Fr Jet Balance catheter and 6 Fr conventional pigtail catheter suspended in a water filled, glass container. A recoil of the catheter caused by injection was observed for a 6 Fr conventional catheter; however, no catheter movement was observed when a 5 Fr Jet Balance was used. To evaluate clinical usefulness of the 5 Fr Jet Balance, we compared the number of incidence of ventricular ectopy during left ventriculography between 5 Fr Jet Balance and 6 Fr conventional pigtail catheters. In 104 consecutive patients who underwent left ventriculography, a 5 Fr Jet Balance was used in 55 patients (5 Fr Jet Balance group), and a 6 Fr conventional pigtail in 49 patients (6 Fr conventional pigtail group). The 5 Fr Jet Balance group had a significantly lower incidence of VPB (21.8% vs. 42.9%, P = 0.02), ventricular tachycardia (1.9% vs. 14.3%, P = 0.02), and multiple VPB (9.0% vs. 34.7%, P = 0.001), respectively, than the 6 Fr conventional pigtail group. In conclusion, a 5 Fr Jet Balance pigtail catheter is useful and safe as regard to the incidence of ventricular ectopy during left ventriculography. Cathet. Cardiovasc. Intervent. 48:220-225, 1999.

Aged↗
PubMed1999

Establishment and characterization of human pancreatic carcinoma lines with a high metastatic potential in the liver of nude mice.

To investigate of human pancreatic cancer metastasis to the liver, a pancreatic carcinoma line, HPC-3, was injected into the spleens of nude mice. The cells from a few liver metastatic foci of the mice injected with HPC-3 were expanded in vitro and subsequently injected into the spleens of nude mice. By repeating these procedures, we were able to obtain a cell line, designated HPC-3H4. The mice were observed to have liver metastasis in 6 of 6 (100%) cases injected with HPC-3H4, whereas the rate was 0% at 3 weeks after the intrasplenic injection of HPC-3. The tumorigenicity of HPC-3H4 was more rapid than that of HPC-3. The motile activity of HPC-3H4 was also stronger than that of HPC-3, and the adhesion to the extracellular matrix of HPC-3H4 was stronger than that of HPC-3. We also analyzed the cell surface expression of the metastasis-related adhesion molecules. As a result, no substantial changes were observed in the expression level of adhesion molecules. These results suggest that HPC-3H4 is useful for studies aimed at the prevention of liver metastasis.

Animals↗
PubMed1999

Nipple discharge disorders: current diagnostic management and the role of fiber-ductoscopy.

Nipple discharge disorders is a field in which there has been both increasing awareness on the part of patients and advances in management. Today secretion from nipples can be classified according to its color, cellularity and biology. To be significant a discharge should be true, spontaneous, persistent and non-lactational. Moreover there are methods to differentiate patients who require surgical intervention from those who do not. Surgically significant nipple discharges are watery, serous (yellow), serosanguineous and bloody. Cytology smears of discharge material have helped to classify the cellular material, providing information about normality, atypia and malignancy and also about papillary formation of the exfoliated cells. Tests such as Hemoccult help to discover occult blood in the secreted fluid. Modern immunological tests can be performed on cytology smears where occurrence of high levels of carcinoembryonic antigen could indicate a latent malignancy. Galactography investigation is today the state-of-the-art approach to investigate patients with nipple discharge disorders and this examination can demonstrate the size, location and extent of an intraductal abnormality. Modern high-resolution ultrasound techniques are helpful in visualizing intraductal disorders and are becoming a good complementary approach if not an alternative to traditional radiology techniques. Recently even MR galactography has been shown to be of diagnostic value, but not as informative as regular galactography. The most sophisticated investigation method, which can also be used therapeutically, is fiber-ductoscopy of the concerned duct in a breast. This technique, although expensive and in its infancy, is a fascinating and promising approach for inspecting the intraductal lumina. In this article the background, current investigation methods and possibilities of the technique are described, as well as the most sophisticated ways to deal with nipple discharge disorders in human breasts.

Breast Diseases↗
PubMed1999

Vascular anatomy of the pancreaticoduodenal region: A review.

Vascular anatomy of the pancreaticoduodenal region has been the subject of numerous studies. However, several essential areas of confusion remain in interpretation of the vascular configuration. We note and discuss three key points in relation to this confusion: (1) a missing vascular arcade, (2) a rearrangement of the arcade by collateral and/or transverse vessels, and (3) a solitary vessel without an accompanying comites vein or artery. In addition, we consider that different interpretations as well as varying reported incidences depend on different "thresholds" when observations are made. Consideration of new aspects of vascular anatomy of the pancreaticoduodenal region is required for further improvement of surgical procedures. In terms of the selection of lymph node resection procedure, we discuss mainly the inferior arterial origin. Special attention should be paid to the ligation of inferior arteries because of the high incidence of the common trunk formation of the upper jejunal and inferior pancreaticoduodenal arteries. With regard to duodenum-preserving pancreatic head resection for benign tumors, our observations are introduced in view of either arterial or venous configuration. First, a communicating artery between the anterior and posterior arterial arcades is noted because of its possible critical role in blood supply to the papilla of Vater. Second, a venous drainage route from the duodenum to the retroperitoneal space in "normal" specimens is described.

Dissection↗
PubMed1999

Adult onset limb-girdle type mitochondrial myopathy with a mitochondrial DNA np8291 A-to-G substitution.

We analyzed mitochondrial DNA (mtDNA) from 7 patients in four families with adult onset limb-girdle type mitochondrial myopathy to clarify their genetic background. The patients, 2 men and 5 women, showed common clinical features, characterized by isolated skeletal myopathy, high serum creatine kinase level, ragged-red fibers and cytochrome c oxidase-defective fibers. Analysis of muscle biopsy specimens indicated that cytochrome c oxidase activity was decreased relative to that of citrate synthase in 5 of the 7 patients. Southern blotting and direct sequence analyses showed an A-to-G homoplasmic transition at np8291 and intergenic COII/tRNA (Lys) 9bp deletion in all patients. This substitution was detected in only 2 of 600 control individuals including healthy subjects and patients with other neuromuscular disorders; these 2 individuals had diabetes mellitus and myotonic dystrophy, respectively. Consequently, the mtDNA transition at np8291 was a rare polymorphism. However, the 7 patients we studied had identical clinical, pathological, biochemical, and genetic features. Therefore, limb-girdle type mitochondrial myopathy with this rare polymorphism may form a subgroup of adult onset mitochondrial myopathy.

Adult↗
PubMed1999

Identification of mRNA for 5-HT1 and 5-HT2 receptor subtypes in human coronary arteries.

OBJECTIVE: Although pharmacological studies have indicated that serotonin (5-HT)-evoked contraction of the human coronary artery is mediated by 5-HT1-like and 5-HT2 receptors, the gene expression of 5-HT receptors is still unclear. We examined mRNA expression of 5-HT1 and 5-HT2 receptor subtypes in human coronary arteries. METHODS: Total RNA was extracted from human coronary arteries of 14 patients at autopsy by the guanidine method. Reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assays were performed to identify 5-HT1 and 5-HT2 receptor mRNA expression in human coronary artery. RESULTS: By RT-PCR, 5-HT1b, 5-HT2A and 5-HT2B mRNAs were detected in all of the 14 patients. 5-HT1A, 5-HT1D, and 5-HT1E mRNAs were detected in only some patients. However, neither 5-HT1F mRNA nor 5-HT2C mRNA was detected in any patient. By ribonuclease protection assay, 5-HT1B and 5-HT2A signals were detected in all patients examined, but neither 5-HT1A, 5-HT1D nor 5-HT2B signal was detected in any patient. CONCLUSIONS: Of 5-HT1/2 receptor subtypes, 5-HT1B and 5-HT2A receptor mRNAs were predominantly expressed in human coronary arteries. Our finding provides molecular evidence that the 5-HT1B receptor may be the 5-HT1-like receptor which mediates constriction of human coronary arteries.

Aged↗
PubMed1999

Gene for hereditary motor and sensory neuropathy (proximal dominant form) mapped to 3q13.1.

Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) has been reported as a new type of HMSN with the disease gene locus in the 3p14.1-q13 region. To further narrow down the gene locus, we performed fine linkage mapping using the linkage disequilibrium method. Analysis of DNA marker haplotypes and genetic cross-over sites showed the disease gene locus to be in the 3.1 cM interval bracketed by D3S1591 and D3S1281. Linkage disequilibrium analysis with DISMULT using 9 marker loci jointly in this region showed a lod score of 4.93 (P < 0.00000095). Consequently, the HMSN-P gene almost certainly lies on chromosome 3q13.1 and shows evidence of linkage disequilibrium.

Chromosome Mapping↗
PubMed1999

Rapid method for detection and detoxification of heavy metal ions in water environments using phytochelation.

Phytochelatins (PCs, (gammaGlu-Cys)n-Gly (n = 2-11)) are produced by higher plants, algae, and some fungi in response to heavy metal ion exposure. A rapid and convenient method for quantifying heavy metal ion concentrations in water environments was developed using a chemically synthesized PC as a mediator. The chelating ability of the PC and quantification of the thiol group were utilized to measure heavy metal ions at low concentrations. The method requires only ten minutes for measurement and only 1 ml of a liquid sample. A range of homogeneous PCs (n = 4-7) were chemically synthesized using a peptide synthesizer. These, especially PC7, exhibited higher sensitivity and consistency of measurement than the native PC from Silene cucubalus, which produced a mixture of PC2, PC3, and PC4. Detoxification of heavy metal ions in vitro by PC was also investigated. Using the paper disc method, the cell growth inhibition zone caused by cadmium ion against Salmonella typhimurium TA1538 was significantly decreased by addition of PC. Furthermore, at the minimum inhibitory concentration of cadmium ion (200 microM) in a nutrient broth culture of S. typhimurium, cell growth was almost completely recovered by addition of PC to the medium.

Journal Article↗
PubMed1999

Catharanthine oxidation in flavin mononucleotide-mediated catharanthine-vindoline coupling reaction for synthesis of dimeric indole alkaloids under near-ultraviolet light.

A reaction model for the flavin mononucleotide-mediated coupling of catharanthine (C) and vindoline (V) under near-ultraviolet light was established based on the results of experiments on the effects of various physical and chemical factors on the disappearance of C and V, and the synthesis of the product, a dihydropyridinium intermediate (IM). The following events were deduced to occur. (i) C is oxidized in the presence of FMN and oxygen under near-ultraviolet light (C(OX1)). (ii) C(OX1) then couples with V to form IM. Degradation of C occurs simultaneously with its specific oxidation, as a result of which a part of the C is converted into the product (C*) which is incapable of coupling with V. When a reaction in which C(OX1) is further oxidized to another form (C(OX2)) is added and the counterpart for the coupling with V is changed to C(OX2) from C(OX1), the reaction model more appropriately describes the exponential increase in the product, IM, that occurs in the early stage of the coupling reaction. (iii) The degradation rate of IM is much greater after C has been consumed than before its disappearance. Using this reaction model, the coupling reactions under basal and optimized conditions were simulated and the results showed a good fit with the experimental values under both conditions. The kinetic study suggests that manganese ion (Mn2+) stimulates the binding of C(OX2) with V in addition to suppressing the degradation of C, resulting in an increased yield of IM. Mn2+ thus appears to be an important factor in the coupling reaction, in which it plays two different roles.

Journal Article↗
PubMed1999

Photoproduction of hydrogen from raw starch using a halophilic bacterial community.

The bacterial community designated BC1, which originates from night soil treatment sludge, exhibited a strong ability to produce H2 from raw starch in the light in the presence of 3% NaC1. Three halophilic or halotolerant bacterial species, Vibrio fluvialis, Rhodobium marinum, and Proteus vulgaris, were isolated from BC1 and identified. The level of H2 production from starch by coculture of V. fluvialis and R. marinum was nearly equal to that by BC1, indicating that these two strains play roles in starch degradation and H2 production from the degraded products in BC1, respectively. Acetic acid and ethanol, which were detected as the major products of degradation of starch by V. fluvialis in pure culture, seemed to be mainly utilized for H2 production by R. marinum in BC1 and the coculture. However, R. marinum in pure culture could not produce H2 from a synthetic medium containing acetic acid and ethanol, suggesting that V. fluvialis supplied not only substrates but also some unknown factors capable of inducing H2 production from these substrates by R. marinum. A study using the starch-rich microalgae, Chlamydomonas reinhardtii and Dunaliella tertiolecta, demonstrated that the above coculture could be applied to the production of H2 at high yield from raw starch in an algal biomass.

Journal Article↗
PubMed1999

Differential response of macrophage subpopulations to myelin degradation in the injured rat sciatic nerve.

Molecular mechanisms of myelin removal by macrophages were explored by examining the immunophenotypes of macrophages following injury of rat sciatic nerve, using a combined method of immunohistochemistry and confocal laser microscopy. In the crush injury model, the involvement in myelin clearance of a cytoplasmic antigen specific for monocytes/macrophages, ED1, was evident. The obvious recruitment of ED1-immunoreactive (-ir) cells was detected first at the crush injury site and then in the distal stump within which Wallerian degeneration had occurred. Double labelling revealed that the ED1-ir cells, except for monocyte-like round cells, always phagocytosed myelin basic protein-ir myelin debris. On the other hand, the expression of ED2, a surface antigen specific for resident macrophages, was significantly different; ED2-ir cells also increased while myelin removal was progressing from day 3 to day 7, but only some of the cells were engaged in myelin phagocytosis. The poor capacity of myelin phagocytosis by ED2-ir cells was supported by the transection model, in which the proximal stump was ligated to suppress regeneration. ED2 may be involved in events other than myelin removal, providing a local environment conducive to axonal regeneration. Our findings thus seem to suggest that ED1 is one of the most reliable markers for cells carrying out myelin phagocytosis, whereas ED2 may participate in entirely different functions. The expression of complement receptor type 3, OX42, was similar to that of ED1 in terms of the swift recruitment of immunopositive cells, their distribution with close association to myelin debris and their high phagocytotic capacity. This supports previously reported in vitro evidence that myelin phagocytosis by macrophages may be complement-mediated.

Animals↗
PubMed1999

Relationship between skin blood flow and sweating rate in prepubertal boys and young men.

We sought the mechanisms in the maturation-related change of skin blood flow to heat stress. Eight prepubertal boys (7-11 years) and 11 young men (21-25 years) were exposed to a mild passive heating [by placing the lower legs and feet in a 42 degrees C water bath for 60 min while sitting in a neutral air condition (25 degrees C, 45% relative humidity)]. No age-related differences were observed for the increase in rectal temperature [0.61 +/- 0.05 (SEM) vs. 0.62 +/- 0.09 degrees C in the boys and men at the end of the passive heating, respectively], mean skin temperature (34.51 +/- 0.28 vs. 34.81 +/- 0.27 degrees C) or metabolic heat production (68 +/- 4 vs. 60 +/- 3 W m-2) during the passive heating. During the heating age-related differences in skin blood flow by laser Doppler flowmetry (LDF) and local sweating rate (m(sw)) varied by site; the boys had greater LDF on the chest and back, similar LDF on the forearm and thigh, lower m(sw) on the chest and thigh, similar (m)sw on the back, and greater m(sw) on the forearm, compared with the men. The relationship between LDF and m(sw) during the heat exposure was divided into three temporal phases: (a) an increase of LDF without an increase in m(sw), (b) an increase of m(sw)without the secondary increase of LDF, (c) a proportional increase of LDF and m(sw) increase of LDF in phase (a) and the slopes of the regression lines between the LDF and m(sw) in phase (c) were significantly greater on the chest and back for the boys (P < 0.05), compared with the men, but not on the forearm and thigh. These results suggest that the greater LDF observed on the trunk in the boys may be owing to a greater withdrawal of vasoconstrictor tone and a greater active vasodilation. Regional differences may exist in the maturation-related alterations in vasoconstriction and vasodilation.

Adult↗