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Biomedical subjects

S Akamatsu

Publications and source records attributed to S Akamatsu.

At least 55 records · Page 3Linked to original sources
PubMed1996

Alpha 2-->3sialyltransferase associated with the synthesis of CA 19-9 in colorectal tumors.

BACKGROUND: A novel assay method specific for alpha 2-->3sialyltransferase that seems to be responsible for the synthesis of CA 19-9 antigen was developed and the levels of the enzyme in colorectal tumor tissues were measured and compared with the levels of alpha 1-->4fucosyltransferase and the CA 19-9 antigen. METHODS: Lacto-N-biose I (Gal beta 1-->3GlcNAc beta, Lewis(c) [Le(c)]) and 6-O-methyl-Le(c) (Gal beta 1-->3[6OMe]GlcNAc beta) were synthesized and covalently attached to bovine serum albumin (BSA). These two substrates were incubated with extracts from colorectal tissues in the presence of cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NeuAc) and their resulting products were detected by a sequential use of anti-BSA monoclonal antibody-coated beads and 125I-labelled anti-sialylated Le(c) antibody. Levels of alpha 2-->3sialyltransferase and alpha 1-->4fucosyltranferase activities and CA 19-9 antigen were measured in the extracts from colorectal tumors and their adjacent normal tissues. RESULTS: 6-O-Methyl-Le(c)-BSA showed a strong acceptor activity compared with Le(c)-BSA and was used as a specific acceptor for alpha 2-->3sialyltransferase. Similar elevation patterns alpha 2-->3sialyltransferase activities and CA 19-9 antigen levels were observed in tumor extracts but no clear correlation was present between the level of alpha 1-->4fucosyltransferase activities and CA 19-9 antigen levels were observed in tumor extracts but no clear correlation was present between the level of alpha 1-->4fucosyltransferase activities and CA 19-9 antigen levels in the same extracts. CONCLUSIONS: The accumulation of CA 19-9 antigen in colorectal tumors might be caused mainly by the activation of alpha 2-->3sialyltransferase but not by that of alpha 1-->fucosyltransferase.

Acetylglucosamine↗
PubMed1996

Elevation of an alpha(1,3)fucosyltransferase activity correlated with apoptosis in the human colon adenocarcinoma cell line, HT-29.

We studied changes in the carbohydrate expression following apoptotic cell death induced by treatment with interferon (IFN)-gamma and anti-Fas antibody using human colon adenocarcinoma HT-29 cells. An apoptotic cell death of HT-29 accompanied with typical DNA fragmentation was observed when the cells, were cultured sequentially with IFN-gamma and anti-Fas antibody. In flow cytometric analyses, the expression of Le(x) and Le(y) antigen was strongly and slightly enhanced, respectively, on the cell surface in accordance with the apoptosis. When the fucosyltransferase (Fuc-T) activities of the lysates from the treated cells were examined relative to those from untreated cells, a 2.5-fold increase of alpha(1,3)-Fuc-T activities and a slight increase of alpha(1,2)-Fuc-T activities were observed, but little or no increase of alpha(1,4)-Fuc-T activity was detected. In Northern blot analyses using probes for Fuc-T III, IV, V, VI and VII genes, strong RNA messages for Fuc-T III, V and/or VI and a weak RNA message for Fuc-T IV were detected in the untreated HT-29 cells. On the other hand, in the treated cells, the messages for Fuc-T III, V and/or VI were found to almost disappear and the 2.3 kb message for Fuc-T IV was observed to elevate 2.8-fold. Therefore, we suggest that the strongly increased expression of Le(x) antigen found on the HT-29 cell surface might be involved in the process of apoptosis, and that the enhancement of the antigen expression seems to result from the increased activity of alpha(1,3)-Fuc-T encoded mainly by the Fuc-T IV gene.

Adenocarcinoma↗
PubMed1996

Histo-blood group Lewis genotyping from human hairs and blood.

The expression of histo-blood group Lewis antigens is determined by the Lewis-type alpha 1-->3/4fucosyltransferase (Le enzyme) encoded by Fuc-TIII gene (Le gene). The genotyping of Le genes by the PCR-RFLP methods established recently and partly modified in this study was found to be useful not only for determining the genuine Lewis blood types of samples such as human hairs and blood stains but also for distinguishing non-genuine Lewis-negative phenotypes frequently observed in pregnant women from genuine ones. The availability of the present PCR-RFLP methods for the paternity tests was also discussed.

Base Sequence↗
PubMed1996

Isolation of group B porcine rotavirus in cell culture.

While group A and C rotaviruses have been grown in cell culture, group B rotavirus has never been cultured. In this study we successfully isolated porcine group B rotavirus in swine kidney cells. Pancreatin treatment is essential for the propagation of group B rotavirus.

Animals↗
PubMed1996

[Perioperative managements of a mentally retarded child with obstructive sleep apnea syndrome for adeno-tonsillectomy].

We describe a mentally retarded child with obstructive sleep apnea syndrome (OSAS) in whom it was difficult to maintain upper airway in the perioperative period. The child underwent awake intubation, because the preanesthetic evaluation of the airway with a direct fiberoptic visualization revealed a very narrow airway. Also we considered that if we used an anesthetic agent, a perioperative airway management would be very troublesome. Postoperatively we continuously monitored for apnea and arrhythmias. When the child was sleeping, we found frequently that her thoratic movements were getting weak and percutaneous oxygen saturation went down to about 70 percent. The preoperative direct fiberoptic visualization of the upper airway is effective for the evaluation of the degree of airway obstruction in this child. We also recommend the continuous intensive postoperative monitorings including pulse oximetry, ECG, and apnea monitor which are very important to avoid life-threatening complications such as upper airway obstruction and serious arrhythmias in patients with obstructive sleep apnea syndrome.

Adenoidectomy↗
PubMed1996

[Anesthetic management of a patient with renal cell carcinoma extending into the right atrium].

A 60-year-old man with renal cell carcinoma extending through inferior vena cava into the right atrium was scheduled for the removal of the right kidney under general anesthesia and the cardiopulmonary bypass technique. In order to obtain a clear operative field and to minimize the risk for pulmonary embolism of necrotizing tumor, total circulatory arrest under profound hypothermia (20 degrees C) was performed. Anesthesia was maintained with high doses of fentanyl (62 micrograms.kg-1), midazolam and supplemented with enflurane. We attempted to prevent circulatory collapse due to acute pulmonary embolism by tumor fragments during operation. The body temperature of the patient was decreased down to 20 degrees C for protecting central nervous system with the minimal damage. No complications occurred during anesthesia and the post-operative period. For the safe anesthetic management of the patient such as our case, adequate monitoring of circulation and protection of central nervous system are essential.

Anesthesia, General↗
PubMed1996

[Prostaglandin E1 at low-doses improved right ventricular ejection fraction in anesthetic management for CABG].

A 52-year-old male for CABG developed a severe right heart failure, because of the direct injury to the right ventricular wall, after cardiopulmonary bypass. The volume loading therapy could not improve the cardiac function, then we used an infusion of low-dose prostaglandin E1 (0.02-0.04 micrograms.kg-1.min-1) for the acute right heart failure with increased pulmonary vascular resistance. After continuous infusion of this dose, the pulmonary vascular resistance decreased quickly, the right ventricular ejection fraction increased, and the stroke volume index also improved. These hemodynamic changes are the result of the potent vasodilating effect of PGE1, that especially could decrease selectively the pulmonary vascular resistance, and increase the preload of the left ventricle. This dose of PGE1, did not cause a severe systemic hypertension that is a serious complication during vasodilating therapy with any vasoactive drugs. In the present case, we speculated that the low-dose PGE1, is effective to improve the right ventricular function during the acute right heart failure which resulted from the intrinsic right ventricular dysfunction.

Alprostadil↗
PubMed1995

Perceiving the sex and race of faces: the role of shape and colour.

Theories of object recognition have emphasized the information conveyed by shape information, whereas theories of face recognition have emphasized properties of superficial features. In the experiments reported here we used novel technology to investigate the relative contributions of shape and superficial colour information to simple categorization decisions about the sex and 'race' of faces. The results show that both shape and colour provide useful information for these decisions; shape information was particularly useful for race decisions while colour dominated sex decisions. When both sources of information were combined, the dominant source depended on viewpoint, with angled views emphasizing the contribution of shape and the full-face view colour. The results are discussed within the context of theories of face recognition and their implications for telecommunication applications are considered.

Adult↗
PubMed1995

Increased plasma alpha (1 --> 3)-L-fucosyltransferase activities in patients with hepatocellular carcinoma.

Alpha (1 --> 3)-L-fucosyltransferase (alpha 1,3FT) activity was determined in plasma of patients with chronic liver diseases, namely, chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC), The plasma alpha 1,3FT activity was significantly higher (p < 0.01) in chronic liver diseases than that in normal controls. The enzyme activity in plasma of patients with HCC was also significantly higher than that in LC (p < 0.05) or that in CH (p < 0.01). However, no significant difference was observed in the enzyme activity between LC and CH. Plasma alpha 1,3FT activity in patients with HCC was not significantly changed before and after transcatheter arterial embolization. In addition, the enzyme activity in the homogenate of the cirrhotic liver tissue was higher than that in the preparation of the hepatoma tissue in the same patient. These results suggest that the increased plasma alpha 1,3FT activity in patients with HCC reflects mainly the enzyme activity of cirrhotic liver tissue, not that of hepatoma tissue. The significance of the elevated levels of plasma alpha 1,3FT and its decreased hepatoma tissue activity in patients with HCC, compared with that in LC, remains to be clarified.

Aged↗
PubMed1995

[Detection of K-ras mutation from malignant cells in sputum with mutant-allele specific amplification (MASA) method].

Sputum cells from 44 lung cancer patients (22 adenocarcinoma, 19 squamous cell carcinoma and 3 small cell carcinoma cases) were examined to contain mutant K-ras genes. The mutant-allele-specific amplification (MASA) method was used for detection of K-ras point mutations. The reaction was designed to amplify only mutant codons with polymerase chain reaction (PCR). Codons 12, 13 and 61 were studied with synthesized primers. Two cases (primary adenocarcinoma of the lung and pancreas adenocarcinoma with lung metastasis) were positive for point mutations at codon 12. The mutation of GGT to GTT was found in the first case and to GAT in the second one. Further experiments with colony hybridization revealed the mutations were found in 1% of alleles in both cases. There were no point mutations found at codon 13 nor 61. Our experiments showed it is possible to detect K-ras mutation in sputum cells from lung cancer patients, with MASA method.

Adenocarcinoma↗
PubMed1995

[Calcitonin gene-related peptide and human atrial natriuretic hormone levels in response to cardiac operation under high dose fentanyl anesthesia].

To elucidate a role of calcitonin gene-related peptide (CGRP) in anesthesia and surgery with cardiopulmonary bypass (CPB), we measured CGRP which is reported to be a marker for fluid overload, simultaneously with HANP (human atrial natriuretic hormone) in 12 patients during high dose fentanyl anesthesia (50-70 microgram. kg-1). Plasma concentration of CGRP increased to 3 times of the value during preanesthetic phase at 30 min after initiation of CPB. A 3-fold increase compared with control in CGRP occurred 30 min after initiation of CPB. A 3-fold increase in HANP also occurred just before termination of CPB. But, there was no correlation between plasma levels of CGRP and HANP. The changes in CGRP did not relate with those of pulmonary capillary wedge pressure. The results of the present study suggest that the mechanism for the increase is unclear, and CGRP could be influenced during cardiac or coronary artery surgery using CPB.

Adult↗
PubMed1994

Molecular genetic analysis of the human Lewis histo-blood group system.

The expression of Lewis histo-blood group antigen is determined by the Lewis type alpha(1,3/1,4) fucosyltransferase encoded in Fuc-TIII gene (Le gene) on chromosome 19. Weak hemagglutination reactions are often observed in the Lewis blood typing to cause false-negative reactions. The level of CA19-9 tumor marker, defined as sialylated Le(a) (sLe(a)), is influenced by the Lewis blood phenotype. The sLe(a) antigen is also considered to play a role in hematogenous metastasis of tumor cells. The accurate genotyping of Fuc-TIII gene would be, therefore, necessary for solving above questions. In addition to the two missense mutations previously reported by us, i.e. the T59G and the G508A, further sequence analyses revealed a new single base substitution, the T1067A, changing the Ile356 to Lys in the catalytic region. Polymerase chain reaction-restriction fragment length polymorphism methods were developed for the detection of these three missense mutations and applied in 15 Lewis negative (le/le) and 65 Lewis positive individuals (Le/Le or Le/le). These methods were found to be useful for genetic diagnosis for the Lewis histo-blood typing. All le alleles had the T59G mutation, whereas none of the Le alleles did. The le alleles were divided in two types, le1, having the G508A mutation, and le2, having the T1067A mutation. The T1067A mutation reduced the enzyme activity less than 10%, whereas the G508A mutation in the catalytic domain made the enzyme completely inactive. The frequency of occurrence of Le, le1, and le2 in the Japanese population by random sampling study was found to be 66, 30, and 4%, respectively.

Alleles↗
PubMed1994

Mechanisms of vasodilation of cerebral vessels induced by the potassium channel opener nicorandil in canine in vivo experiments.

BACKGROUND AND PURPOSE: Nicorandil, a potent antianginal agent characterized as a potassium channel opener, could produce cerebrovascular dilation in in vitro studies. Our aim was to investigate the pharmacologic response to the topical application of nicorandil on the vasomotor tone of pial vessels in vivo. To elucidate its mechanism, we also studied the inhibitory action of methylene blue and glibenclamide against nicorandil-induced vasodilation. METHODS: In 14 dogs prepared with a parietal cranial window, we administered five different concentrations of nicorandil solution (10(-7), 10(-6), 10(-5), 10(-4), and 10(-3) mol/L) under the window and measured pial arterial and venular diameters. After pretreating pial vessels with either 10(-5) mol/L methylene blue or 10(-5) mol/L glibenclamide, we examined inhibitory action after the application of 10(-5) mol/L nicorandil. In additional experiments with 9 dogs, we evaluated the effects of nitroglycerin and cromakalim on pial vessels in the absence or presence of 10(-5) mol/L methylene blue and 10(-5) mol/L glibenclamide, respectively. RESULTS: Nicorandil produced significant, concentration-dependent dilation of pial vessels (P < .05). Methylene blue blocked nicorandil-induced dilation, whereas glibenclamide only attenuated such action of nicorandil. Nitroglycerin and cromakalim also produced a concentration-dependent increase in pial arteriolar and venular diameters (P < .05), and those effects were blocked in the presence of methylene blue or glibenclamide, respectively. CONCLUSIONS: Our in vivo study demonstrates that topical application of nicorandil dilates both pial arterioles and venules in a concentration-dependent manner and suggests that the mechanisms of such actions are most likely due to both cyclic GMP-mediated vascular smooth muscle dilation and the regulation of K+ flux.

Administration, Topical↗
PubMed1994

[The concentration effects of isoflurane-N2O anesthesia on cardiovascular responses to skin incision].

To investigate the concentration effects of isoflurane-nitrous oxide anesthesia on cardiovascular responses to skin incision, we studied 24 non-premedicated patients undergoing lower abdominal operation. Anesthesia was induced with inhalation of 70% nitrous oxide and isoflurane, and maintained with 70% nitrous oxide and three different concentrations of isoflurane (1.25, 1.6, 1.95 MAC). Blood pressure and heart rate were recorded continuously before and after skin incision. Because more than half the patients with 1.95 MAC became hypotensive with systolic blood pressure of less than 80 mmHg just before the skin incision, it was difficult to define the values of MAC BAR (blocking adrenergic responses) in the present study. Cardiovascular responses at skin incision were not completely suppressed at 1.6 MAC isoflurane-N2O anesthesia and no further blocking effects were obtained at 1.95 MAC isoflurane-N2O anesthesia. These results suggest that higher concentration of isoflurane does not guarantee stronger protective effects on stimulation like skin incision.

Abdomen↗
PubMed1993

Transesophageal Doppler echocardiographic assessment of pulmonary venous flow pattern in subjects without cardiovascular disease.

This study was designed to assess pulmonary venous flow dynamics using transesophageal Doppler echocardiography. Under general anesthesia, we studied 54 surgical patients with no history or physical evidence of cardiac disorders. In all patients pulmonary venous flow was easily identified by transesophageal color flow mapping. Pulmonary venous flow pattern, which was obtained clearly in 85% (4654) of patients by transesophageal pulsed Doppler echocardiography, was tri- or quadriphasic. The first wave, which was often biphasic in elderly patients, occurred during ventricular systole (S wave). The second wave occurred in diastole during the early ventricular filling phase of mitral flow (D wave). The third wave was reverse flow toward the pulmonary vein during atrial contraction (A wave). The following variables were measured: the peak flow velocities of each wave (PFVs, PFVd, PFVa), and the ratio of PFVs to PFVd (PFV(S/D)). The PFVd correlated with age (r = -0.56, P < 0.001), indicating age-related decrease. The PFV(S/D) correlated with age (r = 0.61, p < 0.001), indicating age-related increase. These results would indicate that the contribution of pulmonary venous flow during diastole to total pulmonary venous flow decreases with age. Our data suggest that age-related diastolic dysfunction of the left ventricle would affect pulmonary venous flow dynamics and that left atrial storage volume during ventricular systole would increase with age.

Adolescent↗