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Biomedical subjects

M Horimoto

Publications and source records attributed to M Horimoto.

At least 73 records · Page 4Linked to original sources
PubMed1993

Coronary spasm as a cause of coronary thrombosis and myocardial infarction.

A 63-year-old man with an acute anterior myocardial infarction demonstrated an intracoronary nonocclusive thrombus distal to the organic stenosis of the left anterior descending coronary artery. One month after the infarction the thrombus was completely dissolved, and spontaneous and provoked spasm occurred overlying the organic stenosis of the coronary artery. Thus coronary spasm superimposed on the atherosclerotic stenosis was suggested as a cause of the thrombus formation that led to myocardial infarction.

Coronary Angiography↗
PubMed1993

[Electrocardiographic ST-segment deviation in acute inferoposterior myocardial infarction caused by obstruction of the left circumflex coronary artery].

Electrocardiographic ST-segment deviation was evaluated as a method for identifying the occlusive site of the coronary artery in acute inferoposterior myocardial infarction. ST-segment elevation in 2 or more of the inferior leads (II, III, aVF) occurred in 11 of 22 patients (50%) with left circumflex coronary artery occlusion, and in 24 of 27 patients (88.9%) with right coronary artery occlusion. The ST-segment elevation in the inferior leads was 3.8 +/- 2.6 mm (mean +/- SD) in left circumflex coronary artery occlusion and 8.5 +/- 4.9 mm in right coronary artery occlusion (p < 0.01). Two millimeters or greater ST-segment elevation in any 2 or more of the inferior leads was observed in 81.5% of the patients with right coronary artery occlusion, but in only 13.6% of the patients with left circumflex coronary artery occlusion (p < 0.01). ST-segment elevation in the inferior leads was found in 8 of 10 patients (80%) with distal left circumflex coronary artery (segment 13) occlusion, but in only 2 of 9 patients (22.2%) with proximal left circumflex coronary artery (segment 11) occlusion (p < 0.05). These findings suggest that identification of the site of coronary artery occlusion, left circumflex coronary artery or right coronary artery, in patients with acute inferoposterior myocardial infarction can be indicated by the location, summation and intensity of the ST-segment elevation in the inferior leads.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Involvement of endothelin and prostanoids in coronary vasospasm].

The involvement of endothelin, an important endogenous vascular constrictor, and prostanoids in coronary vasospasm was evaluated in 14 patients with and 12 patients without coronary vasospasm who had normal coronary angiograms. Coronary vasospasm was defined as a total or subtotal occlusion or diffuse and intense constriction of the left coronary artery provoked by intracoronary acetylcholine administration and associated with electrocardiographic ischemic ST-segment shifts. Blood samples were taken from the left coronary ostium and the coronary sinus before and during coronary spasm. The blood concentrations of endothelin, 6-keto-PGF1 alpha, and thromboxane B2 were measured. Patients with and without coronary vasospasm demonstrated no significant changes in endothelin and thromboxane B2 concentrations in the coronary sinus blood, or in the difference between left coronary ostium and coronary sinus blood. Patients with coronary vasospasm had 6-keto-PGF1 alpha concentrations in the coronary sinus before and during coronary vasospasm of 133.6 +/- 32.5 and 179.4 +/- 46.7 pg/ml, respectively (p < 0.05), and the differences between coronary sinus and coronary ostium concentrations were -25.7 +/- 29.5 and 41.6 +/- 22.6 pg/ml, respectively (p < 0.05). Patients without coronary vasospasm showed no significant changes in 6-keto-PGF1 alpha concentration. Endothelin and thromboxane A2 are not involved in coronary vasospasm, while prostacyclin concentration rises during coronary vasospasm provoked by acetylcholine.

Acetylcholine↗
PubMed1993

[Vitreous surgery for mycotic endophthalmitis].

We treated eight eyes of five patients with mycotic endophthalmitis. Intraocular inflammatory changes in one of these eyes improved only by antifungal therapy with 21-day administration of miconazole and fluconazole. The other seven eyes underwent vitrectomy, and the preoperative periods between the onset of ocular complications and the operation ranged from one and a half months to three months, during which time fungi were isolated only in one case. Dense vitreous opacities caused by the colonies of the fungi were found in the all vitrectomized eyes. Vitrectomy in the three cases showing no retinal detachment was effective for the improvement of either visual acuity or ophthalmoscopic findings, whereas vitrectomy was not effective in the other two cases with the occurrence of the pre-retinal membrane causing traction retinal detachment. The present investigations suggest that persistent endophthalmitis and the appearance of total retinal detachment made the improvement of retinal changes difficult because of the inflammatory and fibrotic processes between the retina and the vitreous body. It, therefore, is shown that anti-fungal therapy should be initiated when mycotic endophthalmitis is suspected, but in cases without response to the drug, vitrectomy should be performed before retinal detachment occurs.

Aged↗
PubMed1993

[Expression of the protein kinase C genes during liver regeneration].

Protein kinase C (PKC) plays an important role in intracellular signaling. PKC consists of a family of at least eight distinct enzymes. How PKC can be responded to liver regeneration and growth is largely unknown. In an in vivo experiment, regenerating liver after partial hepatectomy (Hx) and carbon tetrachloride (CCl4) administration, expression of the PKC alpha-type was increased, with a single peak, after Hx and CCl4 administration. On the other hand, the PKC epsilon-type gene was activated with biphasic peaks following Hx but was elevated with a single peak after the CCl4 administration. In an in vitro experiment using primary cultured hepatocytes, both of the PKC alpha-type and epsilon-type genes could be induced only by combination of insulin and serum. These results demonstrate that both isoforms of PKC are identically regulated by extra- and intracellular stimuli, thereby influencing growth control of hepatocytes.

Animals↗
PubMed1992

Human chorionic gonadotropin induces c-myc mRNA expression via TSH receptor in FRTL-5 rat thyroid cells.

To elucidate the gene regulation of the thyroid-cell growth-promoting activity by human chorionic gonadotropin (hCG), we investigated the effect of hCG on c-myc proto-oncogene expression in cultured rat FRTL-5 cells by the Northern blot method. hCG induced c-myc mRNA expression, which peaked at 60-120 min. A dose-dependent increase in c-myc mRNA levels was also ascertained. In the presence of crude immunoglobulin G (IgG) from 2 patients with primary hypothyroidism who had blocking type TSH-receptor antibody, c-myc mRNA expressions induced by hCG were decreased to 82% and 62%, compared with that in the presence of normal IgG. The present results suggest that the expression of c-myc mRNA is a part of the molecular mechanism through which hCG regulates the proliferation of thyroid cells, and that hCG-induced c-myc mRNA expression is presumed to be mediated in part by TSH receptors.

Adenoma↗
PubMed1992

Microvascular geometry of the rat heart. Arteriolar and venular capillary regions.

The importance of realistic data regarding microvascular geometry for the understanding of oxygen transport to tissue cannot be underestimated. The purpose of the present investigation was therefore to determine the pattern of capillarization in rat myocardium. The histochemical method used in this study was novel in that it allowed for the discrimination of arteriolar capillary (AC) and venular capillary (VC) regions on the basis of color. Our preeminent finding was that systematic differences exist in microvascular geometry from arteriolar to venular capillary regions in normal rat myocardium. Specifically, VC regions are characterized by greater capillary density; more uniform capillary spacing; shorter segment lengths; and increased capillary diameter. These differences translate to significantly greater capillary length, surface and volume densities on the venular side of the capillary bed. In the face of lower PO2 values towards venules, this distinctive geometry would serve to provide advantageous geometric conditions for oxygen diffusion.

Animals↗
PubMed1992

Production and characterisation of a human monoclonal thyroid peroxidase autoantibody.

A human-mouse hybridoma has been produced by fusion of Hashimoto thyroid lymphocytes with the mouse myeloma line X63-Ag8.653. The cloned hybridoma secreted 2.5 micrograms per 10(6) cells per day of an IgG kappa thyroid peroxidase (TPO) autoantibody (2G4) with high affinity (2.5 x 10(9) molar-1) and specificity for human TPO. 2G4 did not react with lactoperoxidase, horseradish peroxidase or human myeloperoxidase or with porcine TPO or with human thyroglobulin. Plastic tubes coated with 2G4 bound about 50% of 125I-labelled human TPO added and the binding was inhibited by IgGs prepared from 18/18 TPO autoantibody-positive sera. This indicated that all 18 sera contained autoantibodies which recognised the same (or closely related) epitope as 2G4. Plastic tubes coated with IgGs from different TPO autoantibody-positive patient sera also bound 125I-labelled TPO but inhibition by 2G4 in this system was not complete. This suggested that the sera contained at least 2 types of TPO autoantibodies, with only one type of autoantibody reactive with the same epitope as 2G4.

Animals↗
PubMed1992

[A case of painless myocardial injury probably caused by coronary artery spasm].

A 53-year-old male was admitted to the hospital due to electrocardiographic ST-segment elevation in V1-4 with ST-segment depression in the inferior leads, which suggested acute myocardial infarction. He had a cough and a slight fever without chest pain. Serum creatine kinase and its myocardial band were slightly elevated but creatine kinase value did not exceed twice the normal upper limit. Emergent coronary arteriography (CAG) revealed intact coronary arteries. The CAG in a chronic stage again revealed intact coronary arteries. Intracoronary administration of acetylcholine of 100 micrograms to the left coronary artery and 50 micrograms to the right coronary artery provoked diffuse spasm in the right and left coronary arteries. The electrocardiogram (ECG) during the right coronary artery spasm revealed ST-segment depression in the inferior leads with ST-segment elevation in V2 and V3, which resembled the ECG finding at the time of the patient's admission. With intracoronary isosorbide dinitrate, the spasm and ST-segment elevation were resolved. These findings strongly suggest that coronary spasm can cause myocardial injury indicated by a slight elevation of serum creatine kinase value.

Coronary Angiography↗
PubMed1992

[A case of hypereosinophilic syndrome exhibiting left ventricular systolic dysfunction].

A 16-year-old woman suffering from bronchial asthma since 2 years previously was admitted to the hospital because of high grade fever, dyspnea, skin eruption and arthralgia. Laboratory data revealed pronounced eosinophilia with elevated immunoglobulin E value. A chest X-ray film showed cardiomegaly with pulmonary congestion. Left ventriculograms showed diffusely reduced motion of the left ventricle (LV). Various clinical symptoms and laboratory data were resolved shortly after the administration of corticosteroids, but the LV dysfunction persisted for at least three months. Left ventriculograms 2 years later disclosed a marked improvement of the LV wall motion. In both the acute and the chronic phase, endomyocardial biopsy of both ventricles revealed non-specific histological findings comprising disarrangement of myocytes and interstitial fibrosis, suggesting post-myocarditis. This case was characterized by LV dysfunction possibly due to eosinophilic myocarditis associated with hypereosinophilic syndrome, and by its functional improvement with long-term corticosteroid therapy.

Adolescent↗
PubMed1992

[Coronary spasm-induced acute myocardial infarction associated with intracoronary thrombosis].

A 63-year-old man was admitted with an acute anteroseptal myocardial infarction. Coronary angiography performed 3 hours after the onset of chest pain revealed 99% stenosis of the proximal left anterior descending coronary artery (LAD) with delayed filling and intraluminal thrombus distal to the stenosis. After the intracoronary injection of isosorbide dinitrate, the delayed filling disappeared and a subsequent intracoronary urokinase partially dissolved the thrombus. Repeat coronary angiography in the chronic phase disclosed 75% stenosis of the LAD and disappearance of the thrombus. Intracoronary acetylcholine provoked a coronary spasm at the stenotic site of the LAD, concomitantly with chest pain and ST-segment elevation in the anterior leads. The present case demonstrated that coronary spasm plays an important role in thrombus formation and acute myocardial infarction. To date, the concept has been postulated that a dynamic interaction between atherosclerosis, platelet aggregation and spasm may work to cause coronary thrombosis and subsequently lead to acute myocardial infarction. Our report shed light on the importance of coronary spasm in the pathogenesis of myocardial infarction.

Acetylcholine↗
PubMed1992

[Hypertrophic cardiomyopathy with rapid development of giant negative T-wave within a year: a case report].

A 61-year-old female was admitted to our hospital, presenting hypertension and giant negative T-wave (GNT) on an electrocardiogram (ECG). The ECG taken one year prior to the admission showed left ventricular hypertrophy (LVH) without GNT. Hypertension had been poorly treated during the year previous to her admission. These had been almost no administration of antihypertensive drugs. Echocardiograms, left ventriculograms and magnetic resonance imaging revealed concentric and diffuse LVH. Endomyocardial biopsy of bilateral ventricles disclosed a degeneration of myocytes and their bizarre hypertrophy with disorganization. This pathologic finding was compatible with that of hypertrophic cardiomyopathy (HCM). Although GNT has frequently been noted in apical type of HCM, the alteration from normal T-wave to GNT within a year has rarely been reported. The present case exhibited GNT on an ECG which showed no apical hypertrophy. Since GNT had developed within a year while hypertension was poorly treated, the rapid development of GNT might have been precipitated by hypertension, which possibly altered the hypertrophic pattern of the left ventricle.

Cardiomyopathy, Hypertrophic↗
PubMed1991

Coronary vasospasm as a potential cause of myocardial infarction and paroxysmal atrial fibrillation in a relatively young woman.

Vasospasm-related myocardial infarction in young women with normal coronary arteries has infrequently been reported and vasospasm-related paroxysmal atrial fibrillation (PAF) has rarely been described. We present a 33-year-old woman with old inferior myocardial infarction and postinfarction angina at rest; the angina was accompanied by PAF and electrocardiographic ST-segment elevation in the inferior leads. Coronary angiography revealed normal coronary arteries and intracoronary acetylcholine provoked an intense and diffuse spasm of the right and left coronary artery. The spasm of the right coronary artery was associated with PAF and ST-segment elevation in the inferior leads. Frequently documented PAF, accompanied by chest discomfort and ST-segment elevation in the inferior leads, was more effectively removed with isosorbide dinitrate than with disopyramide. These data suggest that coronary vasospasm is a likely cause of myocardial infarction and even PAF, although the precise mechanism leading to PAF remains unknown.

Acetylcholine↗
PubMed1991

Unilateral diffuse pulmonary artery involvement in Takayasu's arteritis associated with coronary-pulmonary artery fistula and bronchial-pulmonary artery fistula: a case report.

Diffuse involvement of the right pulmonary artery associated with fistulas between the pulmonary artery and systemic artery is reported in a woman with Takayasu's arteritis. The most proximal portion of the abdominal aorta was pronouncedly narrowed and the aortic wall was markedly calcified. Both the celiac artery and the superior mesenteric artery were totally occluded and drained by the meandering artery arising from the inferior mesenteric artery. The proximal right pulmonary artery was focally narrowed and the middle lobe artery was occluded. All other branches of the right pulmonary artery were diffusely narrowed with sparse distributions of their distal branches. Fistulas were identified between the right coronary artery and the right pulmonary artery and between the right bronchial artery and the right pulmonary artery. This is the first English report of Takayasu's arteritis presenting with a coronary-pulmonary artery fistula that is secondary to a diffuse unilateral involvement of the pulmonary artery.

Aorta, Abdominal↗
PubMed1991

Mechanism of thyroid stimulation by human chorionic gonadotropin in sera of normal pregnant women.

To elucidate the mechanism of thyrotropic activity of human chorionic gonadotropin in sera of normal pregnant women, we examined the effect of blockade of the TSH receptor on the serum-induced cAMP accumulation and the effect of hCG on the TSH binding to FRTL-5 cells. In the presence of crude immunoglobulin fractions in sera from patients with primary hypothyroidism, cAMP accumulation induced by both crude and purified hCG, and normal pregnant women serum were significantly inhibited compared with that in the presence of normal IgGs. The mode of inhibition of these IgGs on the cAMP accumulation was similar for TSH and hCG when analysed by Lineweaver-Burk plots. Moreover, binding of [125I]bTSH to the TSH receptor in porcine thyroid cell membrane was apparently inhibited by adding 4 x 10(6) IU/l of purified hCG. Binding studies of TSH in FRTL-5 cells also indicated the dose-dependent displacements of [125I]TSH by hCG. Although half-maximal inhibitory concentration of hCG was about 20 times as high as that of TSH on a molar basis, displacement of [125I]TSH was observed at a concentration of hCG of 10(5)IU/l or more, which could be a physiological concentration of hCG in sera of normal pregnant women. These results suggest that thyrotropic activity of hCG in sera of normal pregnant women is, at least in a part, mediated by TSH receptors.

Animals↗
PubMed1991

Human monoclonal thyroglobulin autoantibodies of high affinity. II. Interaction between thyroglobulin and thyroglobulin autoantibodies of different IgG subclasses.

The interaction of human thyroglobulin (Tg) autoantibodies of different IgG subclasses with Tg was investigated using four high affinity human monoclonal thyroglobulin (Tg) autoantibodies, secreted by human-mouse hybridomas, of subclasses IgG1 (kappa and lambda) and IgG2 (kappa and lambda) and an IgG4 kappa serum monoclonal Tg antibody. With exception of a low level of interference in binding between one IgG1 lambda Tg antibody and one IgG2 kappa Tg antibody (27% decrease), binding by human monoclonal Tg antibodies of one IgG subclass was unaffected by pre-incubation of 125-I Tg (or Tg on an ELISA plate) with a human monoclonal Tg antibody of a different IgG subclass. Furthermore, preincubation of Tg-coated ELISA plates with an IgG1 human monoclonal Tg antibody had little effect on binding to Tg by IgG2, IgG3 and IgG4 Tg antibodies present in the sera of 6 Hashimoto patients. Comparable observations were made using an IgG2 monoclonal Tg antibody and serum Tg antibodies of subclasses IgG1, IgG3 and IgG4. Binding of an IgG1 kappa Tg antibody was inhibited (> 80%) by pre-incubation of Tg with an IgG1 lambda Tg antibody derived by fusion of lymphocytes from the same Hashimoto patient. In contrast, pre-incubation of Tg with an IgG2 kappa Tg antibody had little effect on subsequent binding by an IgG2 lambda Tg antibody derived from lymphocytes of a different Hashimoto patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗