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Biomedical subjects

H Eguchi

Publications and source records attributed to H Eguchi.

At least 163 records · Page 9Linked to original sources
PubMed1992

Sandwich immunoassay for intact human osteocalcin.

To overcome the problems of limited-region specificity associated with conventional radioimmunoassay (RIA), we developed a sandwich enzyme immunoassay (EIA) for intact human osteocalcin (hOC). For this EIA we used antibodies to the N- and C-terminal regions of hOC that were raised against an N-terminal 20-residue peptide and a C-terminal 7-residue peptide, both synthetic. Immunoassay profiles of tryptic digests of hOC and serum from patients with renal failure, fractionated by reversed-phase HPLC, facilitated direct demonstration of the region specificity of this method. A preliminary study of serum osteocalcin concentrations in patients with renal failure further confirmed this specificity, showing lower positive rates obtained by this method than by conventional RIA. The cross-reactivity data of hOC with bovine and rat osteocalcins by the sandwich method indicated its species specificity. These studies demonstrate the superior specificity of this sandwich EIA compared with conventional RIA and thus confirm its potential diagnostic superiority.

Adult↗
PubMed1991

Gene structure and expression of the rat cytochrome P450IIC13, a polymorphic, male-specific cytochrome in the P450IIC subfamily.

The male-specific CYP2C13 gene has been isolated from two independent rat genomic libraries. This gene spans more than 50 kb and contains eight introns which are subject to the GT-AG rule. Two allelic forms of the CYP2C13 gene were identified. Determination of the exonic sequences revealed that one of them encodes cytochrome P450(+g) and the other encodes cytochrome P450(-g). Using allele-specific restriction enzyme sites, a good correlation between the genotype and the phenotype of CYP2C13 was shown. Nucleotide substitutions between the (+g) and the (-g) genes exist not only in the exons but also in the introns and the 5'-flanking region. Although five nucleotide differences were identified within 287 base pairs of the (+g) and (-g) 5'-flanking regions, the transcription initiation sites were identical. In addition to a canonical TATA box located 31 base pairs upstream of the start site of transcription, putative binding sites for the liver-enriched and liver-specific transcription factors HNF1/LF-B1/APF, HNF3, HNF4/AF-1, C/EBP, LAP, and eH-TF/TGT3 and the ubiquitous factors NF-1 and OTF-1 were identified.

Animals↗
PubMed1991

Isotopic study of the effects of platelets on development of intimal thickening in autologous vein grafts in dogs.

The effects of platelets on the development of intimal thickening of arterially transplanted autologous vein grafts was investigated using canine poor run-off models. A new apparatus consisting of a shielding lead block to measure in vivo platelet adherence only on the intima of the vein graft was developed. In 23 dogs, 51Cr-labelled platelets (20 microCi/kg) were injected and isotope emission over the grafts was counted. Platelet adherence was expressed as the thrombocyte accumulation index (TAI), i.e. the ratio of counts over the graft under an abnormal flow condition in the poor run-off model to those over the graft under normal flow conditions of the contralateral leg. The TAI of the total graft (TTAI) was significantly high immediately and on the first and third days after implantation. The TAIs of the proximal (PTAI) and distal (DTAI) portions of the vein graft were also high at these same times. At 7, 10, 14 and 21 days, the TAI was almost equal to 1.0, a time at which endothelial regeneration was complete as confirmed by scanning electron microscopy. Thus, the prominent intimal thickening of arterially transplanted autologous vein grafts in dogs, induced under an abnormal flow condition, correlates well with the enhanced platelet adherence on the intima of the vein grafts in an early period after implantation.

Animals↗
PubMed1991

Significance of the endothelial lining in prevention of intimal thickening of autogenous vein grafts in dogs.

To better comprehend the role of the endothelial lining in occurrence and development of intimal thickening in arterially implanted autogenous vein grafts, two models of canine femoral arteries were prepared. In the Group I model, the implanted autogenous vein graft was kept under a normal flow condition for 2 to 4 weeks after implantation, then was exposed to an abnormal flow (poor run-off). In case of a 3- to 4-week normal flow, intimal thickening was practically nil. Scanning electron microscopic studies showed that this 3- to 4-week period corresponded to that of re-endothelialization of the autogenous vein grafts. Immunohistochemical studies of fibrinogen distribution in the autogenous vein graft wall in the Group II model revealed that the permeation of fibrinogen was enhanced in case of an abnormal flow condition for about 2 weeks after the implantation. We interpret these observations to mean that intimal thickening was induced by an accelerated permeability in the presence of abnormal flow conditions until full re-endothelialization after the implantation.

Animals↗
PubMed1991

Tumor necrosis factor in the cerebrospinal fluid of children with central nervous system leukemia.

To clarify the role of cytokines in cerebrospinal fluid (CSF) in the pathogenesis of central nervous system (CNS) leukemia, three cytokine activities, interleukin 1 (IL-1)-beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma, and their correlations with other laboratory studies of the CSF were analysed in 23 children with acute leukemia. These patients were classified into three groups: group A (n = 8)--patients with overt CNS leukemia, group B (n = 5)--patients with CNS leukemia in remission, group C (n = 10)--patients without CNS disease. IFN-gamma in the CSF was undetectable in these 23 patients. There was no difference in IL-1-beta levels among the three groups. However, TNF-alpha levels were significantly higher in group A than in group B, and higher in group B than in group C. By Kendall's rank sum test, high TNF levels in CSF correlated with high CSF leukemic cell counts and low sugar levels. In two patients with overt CNS leukemia, the TNF level in the CSF decreased gradually with intrathecal chemotherapy. These results indicate that TNF released from stimulated cells in the cerebrospinal space may induce CNS leukemia-related symptoms or alter laboratory parameters measured in the CSF. TNF levels in CSF may also prove useful in diagnosing early CNS involvement in children with acute leukemia.

Acute Disease↗
PubMed1991

Association of neonatal thrombocytopenia and maternal anti-HLA antibodies.

In order to evaluate the influence of maternal anti-HLA antibody on neonatal thrombocytopenia, clinical features and maternal anti-HLA antibody of three groups of infants (19 thrombocytopenic and low birth weight, 27 nonthrombocytopenic and low birth weight, and 80 healthy full-term) were investigated. The incidence of positive maternal anti-HLA antibodies in the three groups was 73.7%, 29.6% and 27.5%, respectively. Thrombocytopenia in small-for-gestational-age (SGA) infants was closely related to the presence of maternal anti-HLA antibodies. Among 20 SGA infants (11 thrombocytopenic, 9 non-thrombocytopenic), anti-HLA antibody was detected in 10 mothers (90.9%) of thrombocytopenic SGA infants, while it was positive in only one mother (11.1%) of nonthrombocytopenic SGA infants. Investigation of the SGA infants revealed that in those whose mothers were sensitized to HLA antigen, not only the platelet count but also the leukocyte and lymphocyte counts in the first week of life were significantly lower than in infants whose mothers were not sensitized. The results suggest that the presence of maternal anti-HLA antibody is a cause of neonatal thrombocytopenia especially in SGA infants.

Antibodies↗
PubMed1991

Surfactant apoprotein A (SP-A) in tracheal aspirates of newborn infants with RDS.

Human pulmonary surfactant contains four groups of apoproteins, SP-A, B, C and D. We determined the concentration of SP-A in the tracheal aspirate of newborn infants by a two-site simultaneous immunoassay with monoclonal antibodies, and used this assay to assess changes in surfactant in various clinical situations. SP-A concentrations were standardized per milligram of albumin in the aspirate. The ratio of SP-A/albumin (micrograms/mg) in tracheal aspirates of 18 preterm infants with respiratory distress syndrome (RDS), in which samples were obtained within 12 hours of birth, was significantly lower (0.2 +/- 0.1 microgram/mg, mean +/- S.D.) compared to a group of 20 non-RDS preterm infants of similar gestational age (15.8 +/- 7.4 micrograms/mg) (p less than 0.05). None of the RDS infants had a SP-A/albumin ratio above 1 microgram/mg within 12 hours of birth, but the ratio exceeded 5 micrograms/mg in all samples from non-RDS infants. The SP-A/albumin ratio significantly increased, however, at 48 to 72 hours after birth in infants with RDS (15.7 +/- 9.5 micrograms/mg). During the recovery phase of RDS, no difference was evident in the SP-A/albumin ratio in babies treated with artificial surfactant compared to those not treated.

Albumins↗
PubMed1991

Hyperglycaemia but not hyperinsulinaemia prevents the secretion of glucagon-like peptide-1 (7-36 amide) stimulated by fat ingestion.

The effect of insulin and glucose on fat-induced gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (7-36 amide) (GLP-1 (7-36 amide)) was studied in five healthy subjects during continuous glucose infusion (Protocol 1) and during hyperinsulinaemic euglycaemic blood glucose clamp (Protocol 2). In Protocol 1, 50 g fat was orally ingested and glucose was infused at a rate of 0.7 g/kg/h for 2 h continuously from the time of fat ingestion. Either glucose infusion alone or fat ingestion alone was carried out in the same subjects as the control. The release of GIP and GLP-1 (7-36 amide) was suppressed in the hyperglycaemic hyperinsulinaemic state. In protocol 2, 50 g of fat was ingested and insulin was infused at a rate of 0.1 U/kg/h with an artificial pancreas system to obtain the normoglycaemic hyperinsulinaemic state. The release of GIP was significantly suppressed in the normoglycaemic hyperinsulinaemic state as well as in the hyperglycaemic hyperinsulinaemic state. However, the release of GLP-1 (7-36 amide) was suppressed in the hyperglycaemic hyperinsulinaemic state but not in the euglycaemic hyperinsulinaemic state. Thus, it is concluded that insulin inhibits fat-induced GIP, but not GLP-1 (7-36 amide), secretion and that glucose is likely to inhibit GLP-1 (7-36 amide) secretion.

Adult↗
PubMed1991

Kupffer cell activity and hepatic microvascular events after acute ethanol ingestion in mice.

After acute ethanol ingestion in C57Bl/6 mice, phagocytic activity of Kupffer cells and hepatic microcirculation were examined by in vivo and electron microscopy. A ratio of Kupffer cells that phagocytosed 0.8 micron fluorescent latex particles to sinusoids containing blood flow (number of Kupffer cells/number of sinusoids containing blood flow) was used as a measure of Kupffer cell phagocytic activity. Three hours after ingestion of 1 gm/kg ethanol, number of Kupffer cells/number of sinusoids containing blood flow increased in both periportal and centrilobular regions by 62% and 66%, respectively, and blood ethanol was no longer detectable. Ultrastructurally, activation of KC was evidenced by the presence of many pseudopodia and filopodia. Numbers of swollen endothelial cells were increased in both regions by 249% and 174%. Interruption of sinusoidal blood flow by leukocytes was aggravated in both regions by 127% and 167%. Thirty minutes and 3 hr after ingestion of 4 gm/kg ethanol, no significant increase in number of Kupffer cells/number of sinusoids containing blood flow was seen, although number of Kupffer cells were also activated as seen with electron microscopy. An increased number of swollen endothelial cells was observed in both regions by 100% and 71% by 30 min and by 200% and 384% by 3 hr. The interruption of sinusoidal blood flow by leukocytes was also increased (periportal = 161%, centrilobular = 196%) as were sticking or plugging leukocytes in sinusoids (periportal = 320%, centrilobular = 120%) by 3 hr. The diameter of centrilobular sinusoids was decreased by 3 hr. Latex particles and platelets were attached to the sinusoidal wall after both low and high dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1990

Effect of ethanol on hepatic oxygenation: evidence of hepatic hypoxia.

The effects of low (1 g/kg body wt) and high doses (4 g/kg body wt) of ethanol on hepatic oxygenation in rats was investigated employing an in vivo microscopic and spectrophotometric system and also a micro oxygen electrode. The low dose of ethanol increased sinusoidal blood hemoglobin oxygenation (ISO2) at periportal regions in the liver lobule. The high dose of ethanol increased ISO2 at periportal regions, but decreased ISO2 at pericentral regions. The low dose of ethanol increased hepatic surface tissue PO2, but the high dose decreased this PO2. From these data it is concluded that the increase of hepatic blood flow, after administration of a low dose of ethanol, compensated for the increase of oxygen demand in hepatocytes but that administration of a high dose of ethanol reduced hepatic tissue oxygenation via an imbalance between delivery and demand of oxygen in pericentral regions of the liver lobule, resulting in local hypoxia in surface hepatic tissue.

Animals↗
PubMed1990

Enzyme immunosensors based on electropolymerized polytyramine modified electrodes.

Highly sensitive amperometric enzyme immunosensors for human immunoglobulin G (IgG) were prepared on the basis of electrogenerated polytyramine (PTy, tyramine = p-(2-aminoethyl)-phenol) modified electrodes. Properties of PTy films changed depending on electrolysis conditions. On the basis of the found properties of the films, an effective IgG sensor was prepared: a PTy film was formed first from an acid solution on a Pt electrode, and the surface was further covered with a PTy film from an alkaline methanol solution to give a PTy doubly coated electrode on which anti-IgG was then immobilized. This electrode provided a large surface area with little non-specific adsorption of proteins. By means of the competitive enzyme immunoassay technique using glucose oxidase (GOD) labeled IgG conjugates, IgG was determined in the concentration range of c. 10 pg/ml-1 mg/ml from the oxidation current of H2O2 generated by the enzyme (GOD) reaction using the above IgG sensor. Also, an anti-IgG immobilized electrode, prepared by using a Pt electrode singly covered with a PTy film from an alkaline methanol solution, acted as an effective IgG sensor with a detection limit for IgG of c. 100 pg/ml.

Antibodies, Anti-Idiotypic↗
PubMed1989

A highly stable NADP-dependent isocitrate dehydrogenase from Thermus thermophilus HB8: purification and general properties.

NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42) was purified to electrophoretic homogeneity from an extremely thermophilic bacterium, Thermus thermophilus HB8, and shown to be a dimeric protein of molecular weight 115,000, with a pI of 5.5. The amino acid composition of the present enzyme was similar to that reported for other bacterial counterparts, except for a high Arg/Lys ratio and a low Cys content. Divalent cations, such as Mn2+ and Mg2+, were essential for activity. The optimal pH was 7.8 at 55 degrees C. The Km values for NADP and D-isocitrate were 6.3 and 8.8 microM, respectively, with a Vmax of 77.6 mumol/min per mg at 55 degrees C. NAD was able to replace NADP with low efficiency. Backward reaction at 40 degrees C indicated that the Km value for 2-oxoglutarate was 63 microM with a Vmax of 4% that of the forward reaction at that temperature. The enzyme was highly stable against high temperature and denaturing reagents.

Amino Acids↗
PubMed1989

Venous reconstruction for iliofemoral venous occlusion facilitated by temporary arteriovenous shunt. Long-term results in nine patients.

In nine patients with iliofemoral venous occlusion, venous reconstructions using a temporary arteriovenous shunt were performed by open thromboendvenectomy with autogenous vein patch angioplasty in four, expanded polytetrafluoroethylene (ePTFE) bypass grafts (including two with external ring-supported ePTFE) in four, and Palma's procedure in one patient. There was an adequate function in the reconstructed venous segments in two of four who underwent thromboendvenectomy and in all four with ePTFE bypass grafting for nine months to 13 years after surgery. In those with a temporary arteriovenous shunt, prepared to maintain patency of the reconstructed venous segments, blood flow through the shunt exceeded 100 mL/min, determined by an electromagnetic flowmeter. Postoperative shunt closure was readily facilitated, using a looping technique and a 2-0 nylon. The increased blood flow through the graft made feasible by the temporary arteriovenous shunt enhanced the patency of the reconstructed venous graft and hence there was an improvement in the affected limb.

Adolescent↗
PubMed1989

Quantitative analysis of transpiration stream dynamics in an intact cucumber stem by a heat flux control method.

Water flux of transpiration stream in an intact stem of the 10 leaf stage cucumber plant (Cucumis sativus L. cv. Chojitsu-Ochiai) was measured by a novel system of heat flux control method with a resolution of 1 x 10(-3) grams per second and a time constant of 1 minute; two heat flux control sensors were attached to the seventh internode and the stem base. The transpiration stream responded clearly to leaf transpiration and root water absorption when the plant was exposed to light, and the water flux at the stem base corresponded to the transpiration rate per plant in steady state. Root water absorption lagged about 10 minutes behind leaf transpiration. Dynamics of water fluxes were affected by the lag of water absorption in roots, and temporary water loss caused by rapid increase in leaf transpiration was buffered by about 5% of the water content in the stem.

Journal Article↗
PubMed1989

Characterization of hepatic hemodynamics in cirrhotics and non-cirrhotics. Effect of glucagon infusion.

The effect of glucagon on hepatic regional hemodynamics was investigated in patients with chronic liver disease during peritoneoscopy with reflectance spectrophotometry. When glucagon was infused intravenously in patients with a non-cirrhotic liver, the regional hepatic tissue oxygen consumption, as estimated spectrophotometrically, increased significantly, whereas the index of hepatic tissue blood volume did not change appreciably, and consequently, the oxygen saturation of hemoglobin in the hepatic tissue blood decreased. In contrast, the administration of glucagon in patients with liver cirrhosis resulted in a significant increase in the index of hepatic tissue blood volume and produced a minor increase in hepatic tissue oxygen consumption. The oxygen saturation of hepatic blood hemoglobin tended to increase in the cirrhotics. The result suggests the presence of functional vasoconstriction at the presinusoidal and/or sinusoidal vessels in the cirrhotic liver, possibly due to a decreased vasomotor activity and/or an abnormal regulatory function of vasoactive substances, which are released by glucagon.

Adult↗