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Biomedical subjects

K Goto

Publications and source records attributed to K Goto.

At least 235 records · Page 13Linked to original sources
PubMed1998

Reaction of alpha-tocopherol in heated bulk phase in the presence of methyl linoleate (13S)-hydroperoxide or methyl linoleate.

alpha-Tocopherol and methyl (9Z,11E)-(S)-13-hydroperoxy-9,11-octadecadienoate (13-MeLOOH) were allowed to stand at 100 degrees C in bulk phase. The products were isolated and identified as methyl 13-hydroxyoctadecadienoate (1), stereoisomers of methyl 9,11,13-octadecatrienoate (2), methyl 13-oxo-9,11-octadecadienoate (3), epoxy dimers of methyl linoleate with an ether bond (4), a mixture of methyl (E)-12,13-epoxy-9-(alpha-tocopheroxy)-10-octadecenoates and methyl (E)-12,13-epoxy-11-(alpha-tocopheroxy)-9-octadecenoates (5), a mixture of methyl 9-(alpha-tocopheroxy)-10,12-octadecadienoates and methyl 13-(alpha-tocopheroxy)-9,11-octadecadienoates (6), alpha-tocopherol spirodiene dimer (7), and alpha-tocopherol trimer (8). alpha-Tocopherol and 13-MeLOOH were dissolved in methyl myristate, and the thermal decomposition rate and the distributions of reaction products formed from alpha-tocopherol and 13-MeLOOH were analyzed. alpha-Tocopherol disappeared during the first 20 min, and the main products of alpha-tocopherol were 5 and 6 with the accumulation of 1-4 which were the products of 13-MeLOOH. The results indicate that the alkyl and alkoxyl radicals from the thermal decomposition of 13-MeLOOH could be trapped by alpha-tocopherol to produce 5 and 6. The reaction products of alpha-tocopherol during the thermal oxidation of methyl linoleate were compounds 6 and 7. Since the radical flux during the autoxidation might be low, the excess alpha-tocopheroxyl radical reacted with each other to form 7.

Chromatography, High Pressure Liquid↗
PubMed1998

Association between MICA gene A4 allele and acute anterior uveitis in white patients with and without HLA-B27.

PURPOSE: Acute anterior uveitis is strongly associated with the HLA-B27 antigen and triggered by the involvement of some external factors. However, it is uncertain whether HLA-B27 itself or other gene(s) near the HLA-B region in a linkage disequilibrium with HLA-B27 predispose to this uveitis. We therefore investigated microsatellite polymorphism in the transmembrane region of the major histocompatibility complex class I chain-related gene A (MICA), located 47 kilobases (kb) on the centromeric side of the HLA-B gene on the short arm of chromosome 6 within 6p21.3. METHODS: We examined the following patients for MICA gene polymorphism by means of polymerase chain reaction and subsequent automated fragment detection by fluorescent-based technology: 64 (37 HLA-B27-positive and 27 HLA-B27-negative) whites with acute anterior uveitis, 74 (67 HLA-B27-negative and 7 HLA-B27-positive) ethnically matched random controls, and 36 HLA-B27-positive healthy controls. RESULTS: The microsatellite allele consisting of four repetitions of GCT/AGC (designated A4 allele) was present at the significantly higher phenotype frequency (71.9%) in the patient group than in the ethnically matched random control group (13.5%) (P < .0000001, corrected P < .0000001). The A4 allele was strongly linked to HLA-B27 in a white population. However, the A4 allele was also found at the significantly higher phenotype frequency (37.0%) even in the HLA-B27-negative patient group than in the ethnically matched HLA-B27-negative control group (4.5%) (P = .0086, corrected P = .043). CONCLUSIONS: These results suggest that the MICA gene itself or other nearby gene(s) linked to the MICA A4 allele may be involved in the development of acute anterior uveitis in a white population.

Acute Disease↗
PubMed1998

Bilateral lung volume reduction surgery via median sternotomy for severe pulmonary emphysema.

BACKGROUND: Lung volume reduction surgery either via sternotomy or by thoracoscopy has been demonstrated to be effective for selected emphysema patients in North America and Europe. The present study summarizes short-term results of bilateral lung volume reduction performed via median sternotomy for the first consecutive 39 patients with severe diffuse emphysema in Okayama, Japan, from July 1995 to February 1997. METHODS: There were 35 men and 4 women, and the age range was 54 to 74 years with a mean age of 65 years. All were former heavy smokers and none of them had alpha1-antitrypsin deficiency. Only 9 patients (23%) showed a bilateral upper lobe pattern of emphysema. The operation was done through a median sternotomy, and the most emphysematous portions were excised bilaterally with a linear stapling device fitted with strips of bovine pericardium to prevent air leakage. RESULTS: No operative death was encountered. The first 33 patients completed 3-month follow-up assessment, and their mean forced expiratory volume in 1 second had improved by 41% from 735 mL to 1,037 mL. Other parameters of pulmonary function tests, arterial blood gas analysis, 6-minute walking distance, and dyspnea scale also had improved significantly. These improvements lasted for at least a year. CONCLUSIONS: Bilateral lung volume reduction surgery via median sternotomy is a safe and effective procedure for selected severe emphysema patients. Although the pattern of emphysema might be different between countries, the results in Japanese patients were similar to those previously reported in North American and European patients.

Aged↗
PubMed1998

Down-regulation of ET(B) receptor, but not ET(A) receptor, in congestive lung secondary to heart failure. Are marked increases in circulating endothelin-1 partly attributable to decreases in lung ET(B) receptor-mediated clearance of endothelin-1?

Receptors for endothelin (ET)-1, a potent vasoconstrictor peptide, have two isoforms, i.e. ET(A) receptors and ET(B) receptors. We previously reported that an ET(A) receptor antagonist greatly ameliorated pulmonary hypertension due to congestive heart failure (CHF) in rats. In the present study of rats with pulmonary congestion secondary to CHF, we determined not only ET(A) receptor mRNA expression but also ET(B) receptor mRNA expression in the congestive lung because lung ET(B) receptors are reported to be important for the clearance of circulating ET-1. We also measured lung ET-1 and circulating ET-1 levels. The expression of ET(B) receptor mRNA in the lung was significantly lower in rats with CHF than in age-matched control rats, while the expression of ET(A) receptor mRNA did not differ between the two groups. The protein level of ET(B) receptor, determined by Western blot, in the lung was lower in the rats with CHF than in the control rats, while the protein level of ET(A) receptor did not differ between the two groups. The lung ET-1 level and plasma ET-1 level were significantly higher in the rats with CHF than in the controls by 1.4-fold and 5.3-fold, respectively. Thus, in the rats with CHF, ET-1 was increased to a much greater extent in plasma than in the lung. The present findings suggest that selective down-regulation of ET(B) receptor, but not ET(A) receptor, occurs in the congestive lung. Since lung ET(B) receptors play a role in the clearance of circulating ET-1, we propose that down-regulation of lung ET(B) receptors partly contributes to marked increases in circulating ET-1 and that increased ET-1 in the circulating plasma as well as in the lung is involved in the progression of pulmonary hypertension in CHF.

Animals↗
PubMed1998

Phosphoramidon, an inhibitor of endothelin-converting enzyme, prevents indomethacin-induced gastric mucosal damage in rats.

Endothelin-1 (ET-1) is produced from inactive precursor big ET-1 by endothelin-converting enzyme-1 (ECE-1), a membrane-bound metalloprotease, structurally similar to another metalloprotease, neutral endopeptidase 24.11 (NEP). Although both phosphoramidon and thiorphan are metalloprotease inhibitors, the ECE activity is inhibited by phosphoramidon but not by thiorphan, a specific inhibitor of NEP. Therefore, to investigate whether an ECE inhibitor can prevent indomethacin-induced gastric mucosal damage in rats, we compared the effects between the two metalloprotease inhibitors on both gastric mucosal integrity and the levels of ET-1 and big ET-1 in gastric tissue. Phosphoramidon significantly decreased ET-1 levels, causing a concomitant big ET-1 increase and dose-dependently attenuated indomethacin-induced gastric mucosal damage. By contrast, thiorphan neither changed the ratio of ET-1/big ET-1 nor attenuated the damage. In conclusion, the prevention of gastric mucosal damage by an ECE inhibitor indicates that endogenous ET-1 may play an important role in the pathogenesis of indomethacin-induced gastric mucosal damage.

Animals↗
PubMed1998

Analgesic effect of mofezolac, a non-steroidal anti-inflammatory drug, against phenylquinone-induced acute pain in mice.

The oral administration of mofezolac, [3,4-di(4-methoxyphenyl)-5-isoxazolyl]acetic acid, resulted in the suppression of writhing induced by the intraperitoneal injection of phenyl-p-benzoquinone (phenylquinone, PQ) in mice. The analgesic activity of mofezolac was almost as potent as that of indomethacin, and more potent than that of sodium diclofenac, zaltoprofen, NS-398, and etodolac when their 50% effective doses were compared. The in vitro inhibitory activity of mofezolac against ovine cyclooxygenase (COX)-1 was also more potent than that of any other non-steroidal anti-inflammatory drugs (NSAIDs) tested, whereas the activity of mofezolac against COX-2 was relatively weak. A Western analysis revealed COX-1 to be constitutively expressed, whereas COX-2 was hardly expressed until 30 min after the PQ-injection in the peritoneal cells. Because the writhing terminated within 30 min after PQ-injection, the prostaglandins involved in the induction of writhing seem to be derived from COX-1. These data thus indicate that potent analgesic activity of mofezolac against the present model to be more closely related to its potent inhibitory activity against COX-1 but not against COX-2.

Analgesics↗
PubMed1998

Enhanced depressor and hyperemic responses to calcitonin gene-related peptide in spontaneously hypertensive rats.

Intravenous (i.v.) bolus injection of calcitonin gene-related peptide (CGRP) caused a depressor response, which was significantly larger in 12-week-old spontaneously hypertensive rats (SHR) than in Wistar-Kyoto rats (WKY). CGRP also caused decreases in carotid and hindquarter vascular resistance, the magnitude of which was larger in the carotid than the hindquarter. In both regions, the vasodilator response to CGRP was significantly larger in SHR than WKY. Plasma CGRP level was significantly lower in SHR than WKY. These results suggest that depressor and vasodilator responses to CGRP are enhanced in SHR and that decreased plasma CGRP level in SHR may contribute to the enhanced responses.

Age Factors↗
PubMed1998

Microsatellite polymorphism within the MICB gene among Japanese patients with Behçet's disease.

Behçet's disease (BD) is known to be associated with HLA-B51. In order to investigate the influence of the MICB gene, located about 120 kb centromeric of the HLA-B gene, on the susceptibility to BD, (CA/TG) dinucleotide repeat microsatellite polymorphism in intron 1 of the MICB gene was investigated among 77 Japanese patients with BD, 60 randomly selected controls and 28 HLA-B51-positive unrelated healthy controls. There was no significant difference in the phenotype frequency of the microsatellite polymorphism between the BD patients and controls. This result suggests that the MICB gene itself is not responsible for the development of BD, and that the candidate gene(s) for BD is located between the MICA and HLA-C genes.

Behcet Syndrome↗
PubMed1998

Impaired blood-brain barrier function in angiotensinogen-deficient mice.

Astrocytes in the central nervous system have physiologically important roles in the response to brain injury. Brain damage results in disruption of the blood-brain barrier (BBB), producing detachment of astrocyte endfeet from endothelial cells. The resultant leakage of serum proteins from loosened tight junctions between endothelial cells produces brain edema. At the same time, reactive astrocytes migrate to the injured area, where they proliferate and produce extracellular matrix, thereby reconstituting the BBB. As astrocytes are known to express angiotensinogen, which is the precursor of angiotensins (AI to AIV), we have investigated a possible functional contribution of angiotensinogen or one of its metabolites to BBB reconstitution. The astrocytes of angiotensinogen knockout mice had very attenuated expression of glial fibrially acidic protein and decreased laminin production in response to cold injury, and ultimately incomplete reconstitution of impaired BBB function. Although these abnormalities were rescued by administration of AII or AIV, the restoration of BBB function was not inhibited by AII type 1 and 2 receptor antagonists. These findings provide evidence that astrocytes with angiotensins are required for functional maintenance of the BBB.

Angiotensin II↗
PubMed1998

Fatal obstructive lung disease after haploidentical sibling cord blood transplantation.

We report the case of a patient with fatal obstructive lung disease after an HLA-haploidentical sibling cord blood transplant (CBT), with severe acute GVHD. A 2-year-old girl developed expiratory air trapping gradually with acute and chronic GVHD after CBT for the treatment of ALL. Anti-CMV and immunosuppressive therapy were ineffective, and the patient died of progressive respiratory acidosis. Necropsy of the lung revealed severe bronchiolitis obliterans with cytomegalic inclusion cells in the granulation tissues of the bronchiolitis. Thus, immunologic and GVHD problems can occur even in CBT.

Bronchiolitis Obliterans↗
PubMed1998

Two cases of chromosome 4q35-linked early onset facioscapulohumeral muscular dystrophy with mental retardation and epilepsy.

Two cases of early onset facioscapulohumeral muscular dystrophy (FSHD) with mental retardation and epilepsy are reported. They were sporadic, unrelated, severely affected females. In both cases, Southern blot analysis of the EcoRI-digested genomic DNA, using probes p13E-11 and pFR-1, detected the shortest 10 kb EcoRI fragments reported to date. Patient 1 showed infantile spasms at the age of 4 months and localization-related epilepsy at the age of 2.5 years. Muscular atrophy in the face, shoulder girdle and upper arms was observed from the age of 4 years. In Patient 2, lack of facial expression was noticed since the age of 1 year, and at 4 years she was noted to have a loss of bilateral upward gaze. She developed localization-related epilepsy at the age of 9 years. From the age of 10 years, weakness of the lower limbs progressed and she became wheelchair-bound at the age of 14 years and 8 months. She had moderate sensorineural hearing loss, a loss of bilateral upward gaze and tongue atrophy. Their IQs were 33 and 45, respectively. The two patients suggest that mental retardation and epilepsy may be part of the clinical spectrum of FSHD, especially in very early onset patients with large deletions.

Adolescent↗
PubMed1998

Development of a huge varix following endovascular embolization for cerebellar arteriovenous malformation. A case report.

We report on the case of a huge varix that developed after the endovascular embolization of a cerebellar arteriovenous malformation (AVM) with a single drainer. A 21-year-old male presented with trigeminal neuralgia which was caused by the dilated drainer of the AVM. A varix was found at the basal vein of Rosenthal 2 months after an initial stage of embolization with polyvinyl alcohol particles; it diminished after the surgical extirpation of the AVM. The varix formation might have been facilitated by the stenosis in the vein of Galen and by the dynamic changes that followed the embolization. This rare complication should be kept in mind when embolization is performed for AVMs with impaired venous outlets.

Adult↗
PubMed1998

Influence of acidosis on cardiotonic effects of milrinone.

BACKGROUND: The present study was designed to determine whether augmentation of cardiac performance by milrinone is affected by acidosis in in vivo canine and in vitro guinea pig preparations, and to elucidate a mechanism in relation to the cyclic adenosine monophosphate (cAMP) formation. METHODS: Halothane-anesthetized, ventilated dogs were randomly assigned to a control group (arterial pH [pHa] approximately 7.4, base excess [BE] > -2 mM; n = 7), mild acidosis group (pHa approximately 7.2, BE < -9 mM; n = 7); or severe acidosis group (pHa < 7, BE < -20 mM; n = 6). Arterial blood pressure, left ventricular pressure (including maximum rate of increase, LV dP/dtmax), and pulmonary blood flow (PBF) were measured. Acidosis was induced by transient hypoxia and maintained with hydrogen chloride infusion. Hemodynamic responses to milrinone infusions at 2 and 5 microg x kg(-1) x min(-1) were then studied. In addition, left atria and right ventricular strips were dissected from guinea pig hearts and suspended in HEPES-Tyrode solution, with pH values adjusted to 7.4, 7, or 6.6. The concentration-response relation of isometric contractions for milrinone (10(-7) to 10(-4) M) and 8-bromo-cAMP (10(-4) to 10(-3) M) were determined. RESULTS: In the control group of dogs, significant increases in LV dP/dtmax (2,674 +/- 822 to 3,999 +/- 1,016 mmHg/s [means +/- SD]) and PBF (2.04 +/- 0.98 to 2.44 +/- 0.96 l/min [means +/- SD]) were seen with a milrinone infusion of 5 microg x kg(-1) x min(-1). In the mild acidosis group, 5 microg x kg(-1) x min(-1) milrinone also increased LV dP/dtmax and PBF. However, neither LV dP/dtmax nor PBF changed in the severe acidosis group. In in vitro experiments, milrinone exerted a positive inotropic effect in a concentration-dependent manner on the right ventricular preparations at pH 7.4, but not at pH 7 and 6.6, whereas no significant difference was observed in inotropic responses to 8-bromo-cAMP at pH values of 6.6, 7, and 7.4 on the right ventricular strips. In the right ventricular in vitro preparation, 10(-4) M milrinone was accompanied by a significant increase in intracellular cAMP content at apH of 7.4 but not 7. CONCLUSIONS: These results indicate that the inotropic effect of milrinone is attenuated by acidosis due, at least in part, to decreased cAMP formation in acidotic muscle.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1998

Cloning of hamster preproendothelin-1 cDNA and its expression in the heart.

To elucidate the pathophysiologic roles of endothelin-1 (ET-1) in the heart, we first cloned and sequenced a part of hamster preproET-1 cDNA from the heart of the CHF146 hamsters. The amino acid sequence has 89% homology to that of rat preproET-1 in the cloned part. The deduced hamster 21-residue mature ET-1 is identical to human, rat, canine, and mouse ET-1. In the next step we investigated the expression of preproET-1 mRNA in the failing heart of CHF146 hamsters. For this purpose, we used 46-week-old CHF146 hamsters and age-matched control healthy hamsters. Left ventricular (LV) + dP/dtmax was significantly lower in CHF146 hamsters than in control hamsters. LV end-diastolic pressure was significantly higher in CHF146 hamsters than in control hamsters, as was central venous pressure. These results suggested that the CHF146 hamsters developed congestive heart failure. The expression of preproET-1 mRNA was greatly enhanced in the LV of the CHF146 hamsters. Because it has been reported that ET-1 induces cardiac hypertrophy and injury to cardiac myocytes in addition to its potent positive inotropic and chronotropic actions, the present findings suggest that endogenous ET-1 plays pathophysiologic roles in the failing heart of CHF146 hamsters.

Amino Acid Sequence↗
PubMed1998

Altered expression of isoforms of myosin heavy chain mRNA in the failing rat heart is ameliorated by chronic treatment with an endothelin receptor antagonist.

We have reported that the production of endothelin (ET)-1 is markedly increased in the failing heart of rats with chronic heart failure (CHF) and that the long-term (3-month) treatment with the ETA receptor antagonist BQ-123 markedly ameliorated the long-term survival and hemodynamic parameters in rats with CHF. In this study we investigated whether this therapy affects the alteration of the mRNA expression of cardiac myosin heavy chain (MHC) isoforms in the hearts of rats with CHF. The change from alpha-MHC to beta-MHC is regarded as a molecular marker for heart failure. The expression of beta-MHC mRNA was dominant in the left ventricle (LV) of CHF rats treated with saline, whereas that of alpha-MHC was dominant in the LV of sham-operated rats treated with saline. Therefore, in the failing rat heart, a change from alpha-MHC to beta-MHC occurred. In the LV of CHF rats treated with BQ-123, this treatment effectively prevents the switching of MHC isoforms. These findings suggest that long-term BQ-123 treatment inhibits the change in MHC isoforms and suggest that this treatment ameliorates heart failure in CHF rats at the molecular level.

Animals↗
PubMed1998

Endothelin-1 in the heart during exercise.

In addition to its potent vasocontractile effects, endothelin-1 (ET-1) has potent positive inotropic and chronotropic effects on isolated heart muscles in vitro. However, it is not known whether the production of ET-1 in the heart is altered by exercise. In this study we investigated the production of ET-1 in the heart during exercise. Rats performed treadmill running of 45-min duration. Sedentary rats served as controls. Immediately after exercise, the heart was quickly removed. The peptide level of ET-1 in the heart was measured by a sandwich-enzyme immunoassay. The peptide level of ET-1 in the heart was significantly higher in the exercise group than in the control sedentary group. Therefore, we have demonstrated that production of ET-1 in the heart is increased by exercise. The present study suggests that myocardial ET-1 participates in the modulation of cardiac function during exercise.

Animals↗
PubMed1998

Abnormal neurohumoral responses to exercise in patients with heart disease: inhibition of an increase in endothelin-1 production during exercise.

We have reported that the plasma endothelin-1 (ET-1) level is significantly increased by exercise in healthy athletes and that it is elevated in the circulation of the non-working leg but not the working leg, suggesting that ET-1 plays an important role in redistribution of blood during exercise. This study was designed to compare alterations of neurohumoral substances by exercise in normal subjects and patients with heart disease. Study patients comprised three groups: eight patients with congestive heart failure (CHF) due to Ebstein's anomaly or single-ventricle heart after Fontan operation; six patients with complete transposition of the great arteries (TGA) after an anatomic surgical correction who may be candidates for ischemic heart disease; and five age-matched normal subjects. All patients were in New York Heart Association functional class I. All subjects performed symptom-limited treadmill exercise. It is suggested that patients with CHF or TGA have a manifest or latent exercise intolerance, respectively. In failed to increase plasma ET-1 level, although it caused a greater increase in norepinephrine, angiotensin II, and arginine vasopressin than in the controls. Exercise also caused a delay in the increased response of plasma ET-1 levels in patients with TGA after an anatomic surgical repair. On the other hand, plasma brain natriuretic peptide (BNP) level was augmented by exercise in patients with CHF and patients with TGA but not in the controls. The present results suggest that an increase in ET-1 production during exercise is absent in patients with heart disease. The mechanisms of inhibition of ET-1 production during exercise in patients with heart disease remain to be elucidated. However, the present study suggests that ET-1 plays an important role in redistribution of blood during exercise, and proposes the possibility that failure of an increase in ET-1 production results in exercise intolerance in patients with heart disease.

Child↗