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Biomedical subjects

H Ando

Publications and source records attributed to H Ando.

At least 253 records · Page 14Linked to original sources
PubMed1995

[Endoscopic treatment of colorectal cancer].

Endoscopic polypectomy should be applied only for early colorectal carcinomas. Intramucosal carcinoma do not have a risk of lymph node metastases. However, there is an about 10% risk of lymph node metastases among carcinomas showing submucosal invasion (sm carcinoma). When risk factors revealed to be positive after polypectomy, subsequent surgical resection of the large bowel with lymph nodes dissection is needed, because these sm carcinomas are considered to have a high risk of lymph node metastases. Therefore, accurate diagnosis of depth of invasion is essential to prevent subsequent surgical resection following endoscopic polypectomy. Endoscopy, barium enema and endoscopic ultrasonography (EUS) are all considered to be effective for an accurate diagnosis of depth of invasion. Endoscopic polypectomy includes hot biopsy, snare polypectomy and endoscopic mucosal resection (EMR). Appropriate maneuver must be chosen, considering the characteristics of the lesion. Major complications after endoscopic polypectomy are bleeding and perforation of the large bowel. Including an establishment of a new risk factors, further efforts must be made to prevent unnecessary additional surgical resection of the large bowel following endoscopic polypectomy.

Aged↗
PubMed1994

Protein synthesis is required for the generation of oscillatory current responses in Xenopus oocyte.

In Xenopus oocyte, direct activation of G-proteins by AIF4- or injection of inositol 1, 4, 5-trisphosphate evoked Ca(2+)-gated Cl-current responses. The current responses were smooth and not oscillatory when tested immediately after the oocyte was isolated. After hours of incubation, the response became oscillatory. This change was prevented by cycloheximide, a protein synthesis inhibitor. Results indicate that the characteristics of Ca2+ signaling system have changed from not oscillatory to oscillatory with time and protein synthesis was required for this change.

Acetylcholine↗
PubMed1994

Mutagenesis of cysteine residues in the human gonadotropin alpha subunit. Roles of individual disulfide bonds in secretion, assembly, and biologic activity.

Human chorionic gonadotropin (hCG) is a member of a family of heterodimeric glycoprotein hormones that contain a common alpha subunit but differ in their hormone-specific beta subunits. Site-directed mutagenesis was used to examine the role of the five disulfide bonds in the alpha subunit on the folding, assembly with the hCG beta subunit, and in cases where dimer formation occurred, receptor binding and signal transduction. Cysteine residues in the disulfide bonds formed by cysteines 7-31, 10-60, 28-82, 59-87, and 32-84 (Lapthorn, A., Harris, D. Littlejohn, A., Lustbader, J. Canfield, R., Machin, K., Morgan, F., and Isaacs, N. (1994) Nature 369, 455-461) were converted to alanine, and these mutants were transfected alone or together with the wild-type hCG beta gene into Chinese hamster ovary cells. The alpha Cys-10, 28, 60, 82, and 84 mutants were not secreted and in most cases were degraded at a faster rate than the native subunit. In addition, these mutants failed to assemble with the hCG beta subunit. Mutants with alterations at alpha Cys-7, 31, 32, 59, or 87 were secreted and combined with the beta subunit. Heterodimers containing a 7-31 double mutant bound to human lutropin-chorionic gonadotropin receptor expressed in transfected human fetal kidney cells, and stimulated cAMP comparable to wild-type hCG. Dimers containing the beta subunit with either single mutant alpha 59, alpha 87, alpha 32, or the alpha 59-87 double mutant showed much lower affinity for the receptor than wild-type hCG. These results suggest that disulfide bonds associated with alpha 7, alpha 31, alpha 59, alpha 87, and alpha 32 are not essential for the alpha subunit to fold into a form that will combine with the hCG beta subunit and to produce a biologically active dimer. This contrasts with observations of the hCG beta subunit where all the disulfide bonds are required for efficient combination and folding (Suganuma, N., Matzuk, M., and Boime, I. (1989) J. Biol. Chem. 264, 19302-19307). In addition, the lack of secretion of some mutants reflects previous observations that proteins which do not fold correctly are rapidly degraded. Thus, alpha subunit mutants which fold properly are secreted and can form heterodimers.

Animals↗
PubMed1994

Direct measurement of increased myocardial cellular 23Na NMR signals in perfused guinea-pig heart induced by dihydroouabain and grayanotoxin-I.

The effects of the cardiac glycoside dihydroouabain (DHO), and the ericaceous toxin grayanotoxin-I (GTX-I) on myocardial cellular sodium (Nai) concentrations were investigated using sodium-23 nuclear magnetic resonance (23Na NMR) spectroscopy at 30 degrees C in isolated perfused guinea-pig hearts. The Nai NMR signals from perfused Langendorff heart preparations were obtained by the modified inversion recovery (IR) method based on the previous observation that the spin-lattice relaxation time (T1) of the Nai (25 or 34 msec at 8.46 Tesla (T)) is much faster than that of extracellular sodium (64 msec at 9.4 T). Nai was estimated from the calibration curve of the frequency area of the 23Na NMR FT spectra plotted against the standard Na concentration. The Nai concentration of the heart increased concomitantly with the positive inotropic effects (PIE) of DHO, GTX-I and monensin (MON). The cumulative sequential addition of DHO (5 x 10(-6) M), GTX-I (7 x 10(-8) M) and MON (5 x 10(-6) M), each of which alone induced no appreciable PIE, produced a 22% elevation in Nai concentration relative to that of the control (100%) accompanying a PIE of 44%. The mechanism of this Nai elevation induced by combinational addition of DHO, GTX-I and MON may be mediated as follows: GTX-I increases the net Na-influx via Na+ channels; DHO inhibits the pumping out of Na+ from the cell; and MON transports external Na+ into the cell, acting as a sodium ionophore. Consequently, these drugs act synergistically to increase the Nai, thereby increasing the intracellular Ca2+ concentration via Na(+)-Ca2+. exchange.

Animals↗
PubMed1994

Molecular cloning of complementary deoxyribonucleic acids for the pituitary glycoprotein hormone alpha-subunit and luteinizing hormone beta-subunit precursor molecules of Japanese quail (Coturnix coturnix japonica).

Complementary DNAs encoding precursor molecules of the pituitary glycoprotein hormone (PGH) alpha- and luteinizing hormone (LH) beta-subunits of Japanese quail were isolated from a quail adenohypophyseal cDNA library using corresponding chicken cDNAs as hybridization probes. The isolated cDNAs had a length of 695 and 724 bp, respectively, and contained sequences of 5' and 3' untranslated regions and an entire coding region of the precursor molecules. Two series of incompletely repeating and partially overlapping nucleotide sequences were observed over a part near the 3' end of the apoprotein coding region and the 3'-untranslated region in the beta-subunit cDNA. One of them consisted of two repeated sets of 71 bases and the other consisted of six repeated sets of 30 bases or less. The predicted amino acid sequence showed that signal peptide and apoprotein of the alpha-subunit consisted of 24 and 96 amino acid residues, respectively, and those of the beta-subunit consisted of 47 and 119 amino acid residues, respectively. Hybridization of the quail PGH alpha- and LH beta-subunit cDNAs to adenohypophyseal RNA showed that sizes of PGH alpha- and LH beta-subunit precursor mRNAs were about 1.1 and 0.9 kb, respectively. Amounts of both mRNAs were increased three to four times by castration in male quail. A comparison of the amino acid sequences of each of the PGH alpha- and LH beta-subunit precursors of the quail and other vertebrates indicated that the apoprotein, especially that of the alpha-subunit, was conserved (59 to 85% and 34 to 55% homology in the alpha- and beta-subunits, respectively), while the signal peptide was diversified (4 to 75% and 4 to 45% homology in the alpha- and beta-subunits, respectively). In the LH beta-subunit apoprotein, interclass homology values varied in a narrow range and did not show a clear relation with the phylogenic distance, while interclass homology values in the alpha-subunit apoprotein and both signal peptides reflected the phylogenic distance. This characteristic feature of the LH beta apoprotein can be explained by assuming that the variable portion of the LH beta apoprotein molecule evolved with a higher speed than that of the other peptides, and consequently no sequence common with other classes remained. This highly variable sequence may be responsible for the high animal-class specificity of the interaction between LH and its receptor.

Amino Acid Sequence↗
PubMed1994

The value of Doppler ultrasound in the diagnosis and management of twin-to-twin transfusion syndrome.

To evaluate the efficiency of the Doppler examination of umbilical arterial blood flow for the antenatal diagnosis and the monitoring of fetal condition during intrauterine treatment of twin-to-twin transfusion syndrome (TTTS), we studied 33 pairs of twins including 5 TTTS cases. In all cases umbilical arterial blood flow was examined by Doppler ultrasound and pulsatility index (PI) was calculated as umbilical arterial impedance. In twins with TTTS, PI of the recipient was outside the normal range and the difference of PI was greater than +0.5. In discordant twins without TTTS and concordant twins, the PI was within the normal range and the difference of PI ranged from -0.5 to +0.5. In 2 cases these findings were found before the appearance of fetal hydrops. In 2 TTTS cases transmaternal digitalization prevented the development of hydrops in the recipient. The difference of PI decreased with improvement in the fetal condition, and vice versa. Our data suggested that, in cases with TTTS, Doppler examination of umbilical arterial blood flow was effective in predicting fetal hydrops. Doppler was also very useful for monitoring the fetal condition during intrauterine treatment.

Adult↗
PubMed1994

Molecular genetic studies of HLA class II alleles in sarcoidosis.

Previous HLA serological studies showed positive associations of the DR52 antigen, the DR52-associated antigens (DR3, DR5 and DR6) and the DR8 antigen with sarcoidosis. To investigate the HLA alleles that may contribute to the genetic susceptibility to sarcoidosis at the DNA level, HLA-DRB1, -DRB3, -DQA1 and DQB1 genotyping using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was performed in 63 Japanese patients with sarcoidosis. The frequencies of the DR52-associated DRB1 alleles (DRB1*11, DRB1*12 and DRB1*14 except DRB1*1302), DRB1*08, DRB3*0101, DQA1*0501 and DQB1*0301 were significantly increased in patients compared with healthy controls. The significant increase of DRB3*0101, DQA1*0501 and DQB1*0301 could be explained by linkage disequilibrium with the DR52-associated DRB1 alleles. It must be noted that the DR8 haplotype, which does not possess the DRB3 gene, also showed a significant increase in sarcoidosis. These results suggest that the HLA-alleles responsible for the susceptibility to sarcoidosis are located at the HLA-DRB1 locus rather than the HLA-DRB3, -DQA1 and -DQB1 loci. In contrast, DRB1*1302 may confer resistance to the disease.

HLA-DQ Antigens↗
PubMed1994

Evaluation of the correlation between in vivo and in vitro release. Effect of the force of contraction and food on drug release.

The effects of the force of contraction in the gastrointestinal (GI) tract and of food on drug release were investigated. Two dosage forms were administered orally to beagle dogs. Dosage form A was a matrix in which drug release was affected by the force of contraction in the GI tract, and dosage form B was not affected by the contraction force. The in vitro dissolution curves from dosage forms A and b using the paddle-beads method were similar to in vivo drug release, with the respective release of up to at least 50%. The in vitro release by means of the paddle-beads method was characterized by the in vivo drug release. The in vivo drug release profile from dosage form A was affected by food. A 1:1 relationship between in vivo and in vitro release was observed up to 6 h in those dogs under the fed condition, but only up to 2.5 h in those under the fasted condition. In the earlier stage of oral administration there was no difference in drug release profile between dogs of the fed and fasted conditions; however, the drug release rate in the fed condition was faster than that in the fasted condition 2-4 h after administration. It was thus assumed that in the fed condition, drug release from dosage form A was affected by gastro-duodenal transit time or by the different environment in the distal parts of the GI tract rather than by the force of contraction.

Administration, Oral↗
PubMed1994

Collateral development induced by repetitive brief coronary occlusion relates to the functional state of pre-existing collaterals.

The effects of pre-existing collaterals (PC) and the perfusion size (PS) on the ischemia-induced collateral development were studied in a canine model. Under aseptic conditions, the dogs were instrumented with pairs of ultrasonic crystals to measure regional wall motion in the territory of the left circumflex (LCX) and left anterior descending coronary artery. A micromanometer was used to measure left ventricular (LV) pressure. Two to 3 weeks after surgery, 2 min coronary occlusion (CO) of LCX was repeated every 32 min consecutively day and night using a remote control, motor-driven hydraulic cuff occluder. Regional wall motion and LV pressure were monitored via a telemetry system in 23 dogs. The functional state of PC was estimated by the level of % reduction of regional wall motion at the end of the first 2 min CO, which ranged from -11 to -141%. PS of LCX area at risk determined by the post mortem angiograms ranged from 35 to 54% (mean +/- SEM; 44 +/- 1%) of LV. Number of CO needed for collateral development ranged from 8 to 628, and was exponentially related to the functional state of PC (r = -0.77, n = 23, p < 0.01), but not to PS (r = 0.43, n = 19, p = 0.07). These results suggest that the functional maturity of pre-existing collaterals is one of the major determinants of collateral development related to ischemic stimuli.

Animals↗
PubMed1994

A case of gastrointestinal bleeding associated with calcific aortic stenosis.

Gastrointestinal bleeding is not rare in patients with calcific aortic stenosis (AS) in Western countries, which has suggested an association between the two conditions. However, there has been no previous report of this association in Japan. In this report we describe a patient with AS who had recurrent gastrointestinal bleeding. An 84-year-old female who had been followed for severe AS presented with recurrent rectal bleeding, but the site of bleeding could not be detected despite various examinations, including endoscopy. She died of progressive heart failure during hospitalization. Postmortem examination disclosed severe left ventricular hypertrophy with calcific aortic stenosis. Microscopically, angiodysplastic lesions were observed in the submucosa throughout the gastrointestinal tract.

Aged↗
PubMed1994

Telescience testbed experiments of intracellular recordings in the Xenopus oocyte.

The feasibility of intracellular recordings under constraints for experimental conditions in outer space were tested at a telescience testbed of the National Space Development Agency of Japan. We attempted to study the dose-response relationship of adenosine-induced potential changes in the Xenopus oocyte. The testbed simulated the distance from a ground control room to oocytes in an orbital laboratory; signals were delayed and compressed from one "station" to other. A microelectrode was inserted into the oocyte using remote control on the manipulator and on the xyz-planes of the platform with stereoscopic pictures observed through a head mounted display. When the transfer rate of the visual signals was decreased from 1.5 Mbps to 128 Kbps, insertion of the electrode became almost impossible because of reduced picture quality. Once the electrode was inserted, however, dose-dependent adenosine responses could be observed with little trouble.

Adenosine↗
PubMed1994

[Analysis of susceptibility genes in sarcoidosis].

In order to investigate immunogenetic mechanisms in the pathogenesis of sarcoidosis, sixty-three patients with sarcoidosis, who were diagnosed histologically, were tested for HLA antigens. Controls consisted of 120 healthy subjects. A lymphocyte cytotoxicity test was used for typing HLA-A, -B, -C, -DQ and -DR antigens. HLA-DP genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The frequencies of HLA-DR52 and its associated antigens (HLA-DR5, -DR6 and -DR8) were significantly increased in the patients as compared to the control subjects. On the contrary, the frequencies of HLA-DR53, -DR1, and -DR4 were significantly decreased in the patients. The frequency of HLA-DPB1*0402 was significantly lower in the patients. No significant differences were observed in HLA-DQ antigens. These results suggest that HLA-DR52 associated antigens contribute to the susceptibility to sarcoidosis in Japanese.

Adolescent↗
PubMed1994

[Feasibility of DNA analysis for prognostic evaluations of colorectal cancer using touch preparations and image cytometry].

The purpose of this study is to demonstrate the applicability of DNA ploidy analysis by using touch preparations obtained from fresh and frozen tissues on the prognostic evaluations of colorectal cancer, especially the development of hepatic metastases. The specimens obtained from surgically resected colorectal carcinomas (32), and hepatic metastases (4), were lightly touched with the slide glasses. Among the 32 patients with colorectal cancers, 7 had synchronous liver metastases, and 5 metastases developed metachronously. After formalin-fixation and Feulgen staining, the DNA analysis was performed by image cytometer (ICM, CAS200R). The data were expressed as the ploidy patterns and DNA indices (p-DNAI: peak DNA index, m-DNAI: mean DNA index), and were correlated very well with those obtained from cytophotometry. The DNA ploidy pattern among the 32 colorectal cancer specimens were Aneuploid(A) in 16, Polyploid (P) in 7, Diploid (D) in 4 and D+P in 5. The cases with synchronous or metachronous liver metastases had a higher m-DNAI (1.74 +/- 0.28) and were Aneuploid in 8, P in 3, and D+P in 1 case. Aneuploidy or Polyploidy predominated among the cases with metachronous liver metastases (4 in 5 cases), with m-DNAI higher than 1.5. Thus, "m-DNA > 1.5" could be a useful prognostic indicator of the high risk group of liver metastases. The liver metastases specimens had Aneuploid and Polyploid patterns in 2 cases each, with m-DNAI ranging from 1.88 to 2.31. DNA ploidy pattern analysis using touch preparations with image cytometry may be useful in determining the prognosis for colorectal cancer.

Adult↗