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Biomedical subjects

I Ito

Publications and source records attributed to I Ito.

At least 109 records · Page 6Linked to original sources
PubMed1991

Crystal-storing histiocytosis and crystalline tissue deposition in multiple myeloma.

Systemic distribution of crystal-storing histiocytes, increasing in number, and widespread crystalline tissue deposition were found in a 75-year-old man with a 5-year history of IgG-kappa-type multiple myeloma associated with corneal opacity and chronic renal failure. Characteristic crystalline inclusions were present not only in myeloma cells but also in cornea, epithelial cells of glomeruli, tubuli, Bowman's capsules, and choroid plexus. Histiocytes had particularly infiltrated the renal interstitium. These inclusions were positive by immunofluorescence for kappa light and gamma heavy chains. By electron microscopy, the inclusions were filled with fine crystalline hexagonal columns, each possessing a core structure. Of various factors generally considered responsible for renal failure in multiple myeloma, marked infiltration of histiocytes and the nephrotoxic effects of light chain appeared most relevant in the present case.

Aged↗
PubMed1990

Mechanisms of stress-induced ST elevation and negative T-wave normalization studied by serial cardiokymogram in patients with a previous myocardial infarction.

Seventeen patients with a previous myocardial infarction were studied during pacing to characterize the clinical correlates of ST elevation, to analyze the relation between ST elevation and negative T-wave normalization and to investigate the mechanism of these electrocardiographic changes. Myocardial ischemia was evaluated by measurement of blood lactate, and wall motion was analyzed using cardiokymographs concurrently and serially. Results show that ST elevation and negative T-wave normalization were most marked in leads containing abnormal Q waves, that ST elevation greater than or equal to 1 mm during pacing was associated with a significant increase in left ventricular end-diastolic pressure and deterioration of left ventricular wall motion and that the magnitude of ST elevation and negative T-wave normalization was significantly correlated, but the latter appeared earlier and more markedly. In addition, there was no significant correlation between the extent of either ST elevation or negative T-wave normalization and myocardial lactate production. Thus, ST elevation and negative T-wave normalization are caused by abnormal left ventricular wall motion rather than myocardial ischemia. Negative T-wave normalization is a more sensitive marker of abnormal wall motion than ST elevation in patients with a previous myocardial infarction.

Cardiac Pacing, Artificial↗
PubMed1990

Cardiac determinants of regression of left ventricular hypertrophy in essential hypertension with antihypertensive treatment.

To study the cardiac determinants of regression of left ventricular hypertrophy in hypertension, left ventricular mass, fractional shortening and end-systolic wall stress were measured echocardiographically in 36 patients with essential hypertension and left ventricular hypertrophy. The patients were classified into two groups. Group I consisted of 15 patients with subnormal end-systolic wall stress, and Group II consisted of 21 patients with normal end-systolic wall stress. There were no significant differences between groups in systolic or diastolic blood pressure. After treatment for 4.4 +/- 1.7 years, echocardiographic studies were repeated. There were no significant differences between groups in the duration of the follow-up period and the kinds of antihypertensive drugs. After treatment, blood pressure decreased significantly in both groups (p less than 0.001 for both), with no significant difference between groups. Left ventricular mass increased significantly in Group I (from 331 +/- 7 to 363 +/- 24 g, mean +/- SEM, p less than 0.05), whereas it decreased significantly in Group II (from 318 +/- 16 to 268 +/- 17 g, p less than 0.001). Myocardial contractility (the relation between end-systolic wall stress and fractional shortening) remained almost the same as before treatment. In conclusion, in patients with hypertensive ventricular hypertrophy with subnormal end-systolic wall stress (inappropriate hypertrophy, probably induced by a neurohumoral factor), a decrease in blood pressure with antihypertensive treatment does not lead to regression of left ventricular hypertrophy, but rather to an increase in left ventricular mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗
PubMed1990

Diurnal change of giant negative T wave in patients with hypertrophic cardiomyopathy.

To examine the diurnal change of negative T wave (deeper than 10 mm in precordial leads) in apical hypertrophic cardiomyopathy and the mechanism of giant negative T wave, 24-h ambulatory electrocardiographic monitoring was performed in 8 patients with apical hypertrophic cardiomyopathy, and effect of atropine on electrocardiogram was studied. The mean depth of negative T wave at 1, 2, and 3 P.M. was 9.3 +/- 3.0 mm, and that at 1, 2, and 3 A.M. was 12.6 +/- 4.8 mm. The mean R-R interval at 1, 2, and 3 P.M. was 792 +/- 113 ms and that at 1, 2, and 3 A.M. was 1055 +/- 94 ms. In seven patients (88%), negative T wave was deeper during the night than during the daytime. There was a positive correlation between R-R interval and depth of negative T wave in 6 patients (75%). Despite significant shortening of R-R interval (879 +/- 116 to 804 +/- 110 ms, p less than 0.05), atropine did not significantly change the depth of negative T wave (14 +/- 5 to 14 +/- 5 mm). In conclusion, negative T wave is not fixed, but is variable, diurnally, probably due to the change of sympathetic tone.

Aged↗
PubMed1990

Sequence analysis and HLA-DR genotyping of a novel HLA-DRw14 allele.

Analysis of a Japanese population by oligonucleotide genotyping revealed that one Japanese HLA-DRw14 allele had a DRB1 genotype different from that of the known HLA-DRw14-related alleles, DRB1*1401 (DRw14-Dw9) and DRB1*1402 (DRw14-Dw16). The second exon of the DRB1 gene of the novel DRw14 allele (designated DRB1-14c) was amplified enzymatically and sequenced after cloning into a plasmid vector. The amino acid sequence of the first domain in the DR beta 1 chain encoded in the DRB1-14c allele was more similar to that of the DRB1*1401 allele (three amino acid substitutions) than to that of the DRB1*1402 allele (six amino acid substitutions). No polymorphic amino acid residue that could explain the common serologic HLA-DRw14 specificity was identified among the sequences of the three DRw14-related alleles. Sequence-specific oligonucleotides (SSOs) were synthesized on the basis of the DRB1-14c nucleotide sequence and used for genotyping of the Japanese population. These SSOs served as useful probes for identifying the DRB1-14c allele in a wide range of donors.

Alleles↗
PubMed1990

Alterations in Fc receptor activity in sinusoidal endothelial cells and Kupffer cells during D-galactosamine (GalN)-induced liver injury in rats. A histological study.

Fc receptors in sinusoidal cells and immune complex uptake were studied histologically in D-galactosamine HCl (GalN)-induced liver injury in rats. Kupffer cells and monocytes were distinguished from sinusoidal endothelial cells and from each other by endogenous peroxidase staining. Fc receptors were found along the sinusoidal endothelium throughout the lobules in normal livers. In acute injury caused by 300 or 750 mg/kg of GalN, Fc receptors were preserved within necrotic foci until the foci were infiltrated by inflammatory cells. The endothelial Fc receptor activity altered, as demonstrated by their capacity to bind immune complexes, after GalN injection. The activity decreased from 24 h after injection in the periportal areas in both dose groups, and increased transiently with dose-dependence in the remaining areas. Kupffer cell numbers also showed a transient dose-dependent increase, except in the periphery of lobules where they generally decreased. In chronic injury with 400 mg/kg, Fc receptors were lost and Kupffer cells decreased in the periportal areas. Circulating immune complexes were ingested by Kupffer cells and endothelial cells in normal and injured livers, showing the the same distribution as that of Fc receptors except that the complexes decreased gradually towards the centrilobular zones.

Animals↗
PubMed1990

Defect of sinusoidal Fc receptors and immune complex uptake in CCl4-induced liver cirrhosis in rats.

The purpose of this paper is to provide a histopathologic basis for abnormalities in immune-complex clearance in liver disease. Fc receptors in CCl4-induced liver cirrhosis in rats were studied by applying peroxidase-antiperoxidase immunoglobulin G complex as a ligand to the frozen sections. Intravenous injection of bovine serum albumin-antibovine serum albumin complexes or colloidal carbon was combined with histological staining for endogenous peroxidase, fibronectin, laminin, or a lectin, Bandeiraea simplicifolia agglutinin I. In the cirrhotic process, sinusoidal Fc receptors showed a weakened reactivity to the ligand with focal absence, and the length of the Fc receptor-positive portion of the sinusoids in unit area decreased to about 50% of the normal value in the advanced cirrhosis. Fibronectin and the lectin showed the presence of sinusoids where Fc receptors were absent. The endothelium in Fc receptor-negative areas did not take up either immune complexes or carbon, and Kupffer cells were absent in these areas. A disturbed immune-complex metabolism was thus suggested to occur in association with the defect of sinusoidal Fc receptors in liver cirrhosis. These abnormalities appeared to not be directly related to perisinusoidal laminin deposition, i.e., capillarization of the sinusoid.

Animals↗
PubMed1990

The immunosuppressant FK-506 prevents progression of diabetes in nonobese diabetic mice.

A novel immunosuppressive compound, FK-506, isolated from Streptomyces has potent immunosuppressive activities. To investigate the effect of FK-506 on the course of diabetes in nonobese diabetic (NOD) mice, we gave this drug to these animals, from the age of 8 weeks, intraperitoneally, in doses of 0.1 mg (2.5 mg/kg/day) or 0.01 mg (0.25 mg/kg/day) three times a week. Overt diabetes were observed in 75.5% of control mice by the age of 20 weeks. In contrast, no diabetes occurred in mice given 0.1 mg of FK-506. Sixteen percent of mice treated with 0.01 mg of the drug became diabetic. Administration of this drug prevented the progression of insulitis in NOD mice. The mice given 0.1 mg of FK-506 lost weight, but this was reversible.

Animals↗
PubMed1990

Pre-junctional inhibitory action of prostaglandin E2 on excitatory neuro-effector transmission in the human bronchus.

The effects of prostaglandin E2 (PGE2) and indomethacin on excitatory neuro-effector transmission in the human bronchus were investigated by tension recording and microelectrode methods. PGE2 (10(-10)-10(-9)M) suppressed the amplitude of twitch contractions and excitatory junction potentials (e.j.ps) evoked by field stimulation at a steady level of basal tension obtained by the combined application of indomethacin (10(-5) M) and FPL55712 (10(-6) M). In doses over 10(-8)M, PGE2 reduced the muscle tone and dose-dependently suppressed the amplitude of twitch contractions. Indomethacin (10(-5) or 5 x 10(-5) M) reduced the muscle tone and enhanced the amplitude of twitch contractions and e.j.ps evoked by field stimulation in the presence of FPL55712. PGE2 (10(-9) M) had no effect on the post-junctional response of smooth muscle cells to exogenously applied acetylcholine (ACh) (4 x 10(-7) M). However, indomethacin (10(-5) M) significantly enhanced the ACh-induced contraction of the human bronchus. These results indicate that PGE2 in low concentrations has a pre-junctional action to inhibit excitatory neuro-effector transmission in addition to a post-junctional action, presumably by suppressing transmitter release from the vagus nerve terminals in the human bronchial tissues.

Bronchi↗
PubMed1990

Sequence analysis and oligonucleotide genotyping of HLA-DR"JX6", a DR"blank" haplotype found in the Japanese population.

We analyzed one of the HLA-DR"blank" haplotypes found in the Japanese population using serologic studies, sequence determination, and genotyping with sequence-specific oligonucleotide (SSO) probes. The DR"blank" haplotype, designated DR"JX6", segregated in a family in association with the DRw52 and the DQw7 specificities. The cDNA and genomic DNA of the DRB1 gene originating from the DR"JX6" haplotype were amplified enzymatically and sequenced after cloning into a plasmid vector. The amino acid sequence of the first domain in the DR beta 1 chain of the DR"JX6" haplotype was different from those of other DR haplotypes sequenced so far, but in the first hypervariable region, the sequence was identical to those of the DRw11, DRw13, DRw14, and DRw17 haplotypes. SSO probes were synthesized on the basis of the DR"JX6" haplotype sequence as well as known sequences of the DRB1, DRB3, and DRB4 genes of other DR haplotypes. These SSO probes were used for the genotyping of Japanese donors whose DRB genes were amplified enzymatically and found to show a hybridization profile that was consistent with the results of serologic studies on the DR"JX6" haplotype.

Amino Acid Sequence↗
PubMed1990

Effects of acutely impaired regional function on remote myocardial wall motion and blood flow in the canine left ventricle studied by coronary occlusion and hypoxic perfusion.

STUDY OBJECTIVE: The aim was to examine whether regional myocardial dysfunction has a significant effect on the wall motion and blood flow in remote non-ischaemic regions. DESIGN: Two different severities of regional dysfunction were produced by occluding the left anterior descending coronary artery and perfusing it with a hypoxic solution. Haemodynamic variables were otherwise identical in the two conditions. The relationship of regional dysfunction in the left anterior descending artery region to regional wall motion and regional myocardial blood flow in the left circumflex artery region were examined. EXPERIMENTAL MATERIAL: 22 anaesthetised mongrel dogs, 9-16 kg, were used for the studies: 14 for the regional wall motion studies, and eight for the regional myocardial blood flow studies. MEASUREMENTS AND MAIN RESULTS: Segment shortening in the left anterior descending artery region was impaired differently in the two conditions: arterial occlusion caused a bulge, while hypoxic perfusion caused only mild hypokinesis. Segment shortening and the myocardial blood flow in the left circumflex artery region were augmented similarly in the two conditions. Left ventricular end diastolic pressure and end diastolic segment length in the left circumflex region were increased and aortic pressure was slightly decreased by left anterior descending artery occlusion and hypoxic perfusion, but there was no significant difference between the two conditions. Heart rate was not affected. CONCLUSION: The augmentation of wall motion and blood flow of the remote myocardium does not depend on the magnitude of acutely induced regional dysfunction per se. The augmented wall motion in the remote region is unlikely to be due to mechanical unloading of the remote myocardium due to an intraventricular regional interaction, but rather to the Frank-Starling mechanism and left ventricular afterload reduction following acute ischaemia.

Animals↗
PubMed1990

Allosteric potentiation of quisqualate receptors by a nootropic drug aniracetam.

1. Allosteric potentiation of the ionotropic quisqualate (iQA) receptor by a nootropic drug aniracetam (1-p-anisoyl-2-pyrrolidinone) was investigated using Xenopus oocytes injected with rat brain mRNA and rat hippocampal slices. 2. Aniracetam potentiates the iQA responses induced in Xenopus oocytes by rat brain mRNA in a reversible manner. This effect was observed above the concentrations of 0.1 mM. Kainate. N-methyl-D-aspartate and gamma-aminobutyric acid responses induced in the same oocytes were not affected. 3. The specific potentiation of iQA responses was accompanied by an increase in the conductance change of iQA and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) responses, but the affinity of receptors for agonist and the ion-selectivity of the channels (reversal potentials) were not changed. 4. Aniracetam reversibly potentiated the iQA responses recorded intracellularly from the pyramidal cells in the CA1 region of rat hippocampal slices. The excitatory postsynaptic potentials (EPSPs) in Schaffer collateral-commissural-CA1 synapses were also potentiated by aniracetam. 5. Population EPSPs recorded in the mossy fibre-CA3 synapses as well as Schaffer-commissural synapses were also potentiated by aniracetam. The amplitudes of the potentiation were not changed by the formation of long-term potentiation.

Action Potentials↗
PubMed1990

Involvement of endothelin in the regulation of human vascular tonus. Potent vasoconstrictor effect and existence in endothelial cells.

Endothelin, a recently discovered endothelium-derived peptide, has been reported to produce potent vasoconstriction in various vessels of experimental animals. To study the involvement of endothelin in the regulation of vascular tonus in humans, isolated human mesenteric arteries were investigated by both pharmacological and immunohistochemical methods. The vasoconstrictor action of endothelin-1 was examined on ring segments of human mesenteric arteries. Endothelin-1 induced a slowly developing and sustained contraction, with an EC50 value (half-maximal effective concentration) of 2.9 x 10(-9) M, two orders of magnitude smaller than that of norepinephrine (EC50 of 3.9 x 10(-7) M), indicating that the vasoconstrictor action of endothelin-1 is about 100 times more potent than that of norepinephrine. The contractile effect of endothelin-1 was affected neither by adrenergic, cholinergic, histaminergic, nor serotonergic antagonists, nor by inhibitors of arachidonic acid metabolism. The vasoconstrictor response to endothelin-1 was effectively antagonized by nicardipine, a dihydropyridine Ca2+ channel blocker. Endothelin-1 profoundly augmented contractile response to Ca2+ in partially depolarized tissues. Immunohistochemical studies revealed for the first time that endothelin-like immunoreactivity was localized in endothelial cells of human mesenteric artery. The results of the present study indicate that endothelin-1 is one of the most potent vasoconstrictors in the human mesenteric artery and that it induces vasoconstriction via an ultimately accelerating Ca2+ influx through voltage-dependent Ca2+ channels. Since endothelin-1 can be located in human endothelial cells, it may play an important physiological or pathophysiological role.

Adult↗
PubMed1990

Clinical characteristics of cardiomyopathy with mild dilatation.

The clinical features of 20 patients with mildly dilated cardiomyopathy (MDCM) were investigated by electrocardiography and echocardiography. MDCM was defined as conditions with: 1) left ventricular end-diastolic dimension between 55 and 65 mm and 2) left ventricular fractional shortening between 10 and 25%. Nine patients (45%) had no histories of congestive heart failure. Eight patients had atrial fibrillation, and the other 12 patients were in regular sinus rhythm. Two patients had supraventricular premature contractions and five patients had ventricular premature contractions. One patient had paroxysmal atrial tachycardia. During the 40-months' span of this echocardiographic study, left ventricular end-diastolic dimension (60.8 +/- 3.8 mm to 57.3 +/- 4.6 mm) and left ventricular fractional shortening (17.2 +/- 4.6% to 22.7 +/- 7.1%) did not change significantly. One patient died suddenly. These results suggest that 1) some patients with MDCM have neither definite histories nor symptoms to suggest heart failure; 2) the hemodynamic conditions of patients with MDCM do not always deteriorate, but rather stabilize, and even improve during follow-up periods; 3) several types of arrhythmias can be observed, even in standard resting electrocardiograms; and 4) patients with MDCM may die suddenly.

Adolescent↗
PubMed1990

[Mitral valve function after open mitral commissurotomy: assessment by Doppler echocardiography].

To evaluate mitral valve function and its long-term outcome after open mitral commissurotomy (OMC), we examined 39 patients using Doppler echocardiography. There were 13 males and 26 females; who were examined a total of 83 times after the surgery at about one year intervals (seven to 240 months, averaging 78 months). We measured the velocity of transmitral blood flow using the continuous wave Doppler method (CWD), and the transmitral pressure half time (PHT), mean velocity (m V) and peak velocity (pV) were calculated. The presence and severity of mitral regurgitation (MR) were assessed by color flow mapping. 1. PHT gradually increased and significantly correlated (r = 0.63, p less than 0.001) with the months passed after OMC. The regression line of PHT in postoperative months was "PHT = 0.70 x PMo + 83" (PMo = postoperative months). The mV and pV tended to increase gradually, but did not significantly correlate with the months passed after the surgery. 2. Among the 39 patients, 28 (72%) had MR, and their severity was classified as 1+ in two, 2+ in 19, 3+ in six and 4+ in one. Among 21 patients who had no MR before OMC, MR appeared in 12 (57%), and its severity was classified as 1+ in one, 2+ in nine and 3+ in two. All five patients with preoperative MR had MR postoperatively, and their severity was classified as 1+ in one, 2+ in two and 3+ in two. The presence of the preoperative MR of the remaining 13 patients was unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Diastolic properties of hypertrophied hearts in essential hypertension: classification by left ventricular wall stress.

Hypertensive cardiac hypertrophy of 20 patients was classified as inappropriate hypertrophy (HH-I) and appropriate hypertrophy (HH-II) according to their end-systolic wall stress, as measured by echocardiography. The differences in systolic and diastolic performances among the HH-I and HH-II subjects and 10 normal controls (NC) before and during isoproterenol infusion were investigated. Eight patients had subnormal end-systolic wall stress (inappropriate hypertrophy) and 12, normal end-systolic wall stress (appropriate hypertrophy). Before isoproterenol infusion, normalized peak rate of a change in left ventricular diameter during systole was significantly greater in HH-I (3.5 +/- 0.8/s) than in NC (2.3 +/- 0.5/s) and HH-II (2.6 +/- 0.6/s) (p less than 0.01 and p less than 0.005), but there was no significant difference between HH-II and NC. There was no significant difference in normalized peak rate of a change of left ventricular diameter during the rapid filling phase among the three groups (4.5 +/- 1.2/s in HH-I, 4.0 +/- 1.6/s in HH-II, and 4.2 +/- 0.8/s in NC). During isoproterenol infusion, normalized peak rate of a change of left ventricular diameter during systole was significantly greater in HH-I (7.0 +/- 1.9/s) than in HH-II (4.8 +/- 1.7/s) and NC (4.8 +/- 0.8/s) (p less than 0.05 and p less than 0.01, respectively), but there was no significant difference between HH-II and NC. Normalized peak rate of a change of left ventricular diameter during rapid filling was significantly less in HH-II (4.8 +/- 1.7/s) than in HH-I (7.3 +/- 1.3/s) and NC (6.5 +/- 0.8/s) (p less than 0.005 and p less than 0.005, respectively), but there was no significant difference between HH-I and NC. These results suggest that hypertensive patients with inappropriate hypertrophy have relatively diminished diastolic velocity (supernormal systolic velocity and normal diastolic velocity) before and during isoproterenol infusion, and that hypertensive patients with appropriate hypertrophy have absolutely diminished diastolic velocity during isoproterenol infusion, in spite of normal diastolic velocity before the infusion.

Adult↗
PubMed1990

[A case of mitral valve prolapse associated with unusual posterior wall motion of the left ventricle: where has the myocardial theory gone?].

A case with mitral valve prolapse was reported in which unusual movement of the posterior left ventricular wall was observed. The patient was a 45-year-old woman. Physical examination revealed loud multiple clicks at the apex. An electrocardiogram revealed T wave inversion in leads 2, 3 and aVF. Two-dimensional and M-mode echocardiography disclosed mid-systolic buckling of the mitral valve and late systolic 'dip' in the posterior wall of the left ventricle. An exaggerated excursion of the posterior wall during early diastole was also recorded by M-mode echocardiography. Pulsed and M-mode color Doppler echocardiography detected unusual anterograde flow near the mitral valve. This flow coincided well in timing with the early diastolic exaggerated excursion of the posterior wall. A discussion was made on the relation between abnormal left ventricular wall motion and mitral valve prolapse.

Echocardiography, Doppler↗