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Biomedical subjects

T Okamura

Publications and source records attributed to T Okamura.

At least 199 records · Page 11Linked to original sources

Autoreactive antibodies following autologous peripheral blood stem cell transplantation.

A 35-year-old woman diagnosed with multiple myeloma (IgG, lambda type, stage IIIA) received an autologous peripheral blood stem cell transplant (PBSCT). She was euthyroid without autoreactive antibodies prior to the transplant. The patient complained of malaise, weight loss and low grade fever 1 month after transplant, despite rapid haematopoietic recovery. Thyroid function tests on day 34 revealed hyperthyroidism associated with anti-thyroid peroxidase antibody. Antinuclear antibody was also detected, and platelet-associated immunoglobulin was increased. These findings disappeared spontaneously by day 62 without treatment. Autoimmune diseases may occur transiently after autologous PBSCT.

Adult↗

High frequency of fusion transcripts of exon 11 and exon 4/5 in AF-4 gene is observed in cord blood, as well as leukemic cells from infant leukemia patients with t(4;11)(q21;q23).

The MLL gene located on chromosome 11q23 and its translocation to the AF-4 gene located on chromosome 4q21 play a pivotal role in leukemogenesis in infancy. Studies of identical leukemic twins have provided evidence of the MLL rearrangement as a fetal event during pregnancy. We analyzed the presence and frequency of the MLL/AF-4 rearrangement in normal cord blood. Although no chimeric mRNA of MLL or AF-4 was detected in 65 cord blood samples, in-frame fusion transcripts of exon 11 and exon 4 or 5 of the AF-4 gene were detected in three of the samples by a nested polymerase chain reaction. When primers of exon 11 and exon 5 of the AF-4 gene were used, two forms of fusion transcripts (AF-4 exon 11/4 or exon 11/5) were detected in 20 of the 65 cord blood samples (31%) and also four of six leukemic cell samples with t(4;11) (67%), whereas such transcripts were not observed in any of 21 peripheral blood samples nor in fetal fibroblasts. These findings suggest that the in-frame fusion of exon 11 and exon 4 or 5 of the AF-4 gene frequently occurs in hematopoietic cells during the intrauterine period, even in a healthy fetus. Although it is unknown whether the proteins of the AF-4 fusion transcripts have some functions, the instability of the AF-4 gene may be associated with the leukemogenesis of infant leukemia.

Chromosomes, Human, Pair 11↗

Effect of thrombopoietin on proliferation of blasts from CD7-positive acute myelogenous leukaemia.

We investigated the effect of thrombopoietin (TPO) on the growth of leukaemic blasts from 30 acute myelogenous leukaemia (AML) patients according to the surface expression of CD7 and CD34: 10 patients were CD7 positive (CD7+), nine were CD7 negative/CD34+ (CD7-/CD34+) and the remaining 11 were CD7-/CD34-. Significant growth response of leukaemic blasts to TPO was observed in 10/10 CD7+, 5/9 CD7-/CD34+ and 2/11 CD7-/CD34- AML cases using 3H-thymidine incorporation. Synergistic stimulatory effects of TPO with stem cell factor (SCF), interleukin-3 (IL-3), granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor were observed in both TPO-responding cases (9/17) and TPO-non-responding cases (8/13). In a leukaemic blast colony assay. significant growth response to TPO was observed in 5/6 CD7+ and 4/17 CD7-AML cases examined. However, the effect of TPO on the growth of CD7+ leukaemic blasts was not so potent as that of IL-3 and SCF, both of which support the proliferation of primitive haemopoietic progenitors. Expression of c-mpl (TPO receptor) was significantly higher in CD7+ AML cases than in CD7- cases, suggesting a relationship between expression of c-mpl and proliferative response to TPO. These data indicate that CD7+ leukaemic blasts express functional TPO receptors and proliferate in response to TPO. These observations also imply that CD7 expression on AML blasts may indicate involvement of leukaemic progenitors at an early stage of multipotent haemopoietic stem cells.

Adolescent↗

Fluorine-18 fluorodeoxyglucose positron emission tomography imaging of parotid mass lesions.

Using X-ray CT or magnetic resonance imaging (MRI), fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies were performed in 28 patients with parotid lesions. All lesions except two showed higher accumulation of FDG than normal parotid gland. High accumulation was found in all of 5 carcinomas, all of 6 Warthin's tumors, and 8 of 12 pleomorphic adenomas, with standardized uptake values (SUVs) over 3.0. The mean SUVs of carcinomas, Warthin's tumors, and pleomorphic adenomas were 5.92 +/- 2.05, 7.03 +/- 2.49, and 4.07 +/- 1.55, respectively. On the other hand, all 5 inflammatory lesions demonstrated low accumulation, with mean SUVs of 1.66 +/- 0.89. It is thus difficult to differentiate malignant from benign parotid lesions by SUV on FDG-PET.

Adult↗

Comparison of the effects of pancuronium and vecuronium in canine coronary and renal arteries.

BACKGROUND: Pancuronium has sympathomimetic actions but does not change or lowers systemic blood pressure in some studies of anesthetized humans and dogs. The present study was done to determine the actions and mechanisms of action of pancuronium on coronary and renal arteries other than those as a sympathomimetic agent. METHODS: Helical strips of coronary and renal arteries from mongrel dogs were suspended in oxygenated, warmed Ringer-Locke solution, and changes in the isometric tension were recorded. In some strips, transmural electrical stimulation (5 Hz for 40 s) was applied to activate perivascular adrenergic nerves. RESULTS: Pancuronium (10[-7] to 10[-5] M) caused dose-dependent relaxation in coronary and renal arteries contracted with prostaglandin (PG) F2alpha, whereas no significant response was induced with vecuronium. The relaxation was endothelium independent and abolished by indomethacin or tranylcypromine, a PGI2 synthase inhibitor. Transmural electrical stimulation caused coronary arterial relaxation, which was augmented by pancuronium and vecuronium. Desipramine also increased the response, and additional potentiation of the response was not elicited by pancuronium and vecuronium. In renal arteries, electrical stimulation caused contraction, which was also augmented by pancuronium and vecuronium. With desipramine treatment, these muscle relaxants did not potentiate the response. Endothelium-dependent coronary arterial relaxation caused by bradykinin was not affected by pancuronium. CONCLUSIONS: Pancuronium-induced relaxations in canine coronary and renal arteries appear to be mediated by PGI2 released from subendothelial tissues. Potentiations by pancuronium and vecuronium of the response to adrenergic nerve stimulation are expected to be due to an inhibition of the norepinephrine uptake but not to facilitated release of the amine.

Animals↗

Mechanisms underlying the neurogenic relaxation in dog isolated hepatic arteries.

In canine hepatic arterial strips responding to nicotine with contraction, prazosin abolished the response or reversed it to a relaxation. Mechanisms underlying the relaxation were analyzed in hepatic and coronary arterial strips denuded of the endothelium and treated with prazosin and indomethacin. In the hepatic arterial strips precontracted with prostaglandin (PG) F2alpha, nicotine-induced relaxations were not influenced by atropine but were inhibited by timolol and abolished by hexamethonium. Treatment with [8-37] calcitonin gene-related peptide ([8-37] CGRP), a selective CGRP1-receptor antagonist, also attenuated the nicotine-induced relaxation, but a vasoactive intestinal polypeptide antagonist was without effect. Combined treatment with timolol and [8-37] CGRP depressed the response to a greater extent than either antagonist alone. The slight relaxation remaining under the combined treatment was abolished by NG-nitro-L-arginine (L-NA) and restored by L-arginine. In coronary arterial strips precontracted with PGF2alpha, nicotine produced a moderate relaxation, which was abolished or markedly inhibited by treatment with hexamethonium or timolol but was unaffected by L-NA. It is concluded that the nicotine-induced relaxation is mediated by norepinephrine, CGRP, and NO released from perivascular nerves in dog hepatic arterial strips; the responses associated with activations of beta-adrenoceptors and CGRP1 receptors are predominant over those to NO. The coronary arterial relaxation seems to be mediated by neurogenic norepinephrine but not by NO.

Animals↗

Renal adenoma associated with renal cyst formation.

We report a renal adenoma associated with renal cyst formation in a 49-year-old male. A small renal mass inside a right renal cyst was discovered incidentally by ultrasonography. A right nephrectomy was performed. A pathologic examination revealed a well-differentiated, benign papillary tumor which was composed of slightly eosinophilic cells. We therefore diagnosed this patient as having a renal adenoma with hemorrhage.

Adenoma↗

[Detection of intrathoracic infectious lesions using In-diethylenetriamine pentaacetic bicyclic anhydride-IgG (111In-DTPA-IgG) scintigraphy].

The utility of 111In-DTPA-IgG imaging for the detection of intrathoracic lesions was evaluated in 10 patients with the suspicion of inflammatory or infectious diseases. They were intravenously administered 40 or 80 MBq of 111In-DTPA-IgG, and scanned after 24 or 48 hours. Of these, 8 cases, consisted of 4 cases with pneumonia and 2 cases with lung abscess and one case of pulmonary tuberculosis and one of a tuberculous pleuritis, showed true positive results. Others were one false negative case of pneumonia and one true negative case of lung cancer. Overall sensitivity and specificity were 88.9% and 100%, respectively. There were no cases which showed side effects or abnormal laboratory findings caused by the radiopharmaceuticals administered. Thus, 111In-DTPA-IgG imaging is a useful tool for the detection of intrathoracic infectious lesions.

Adenocarcinoma, Papillary↗

Monkey corpus cavernosum relaxation mediated by NO and other relaxing factor derived from nerves.

Isolated monkey corpus cavernosum muscle strips contracted with prostaglandin F2 alpha and treated with prazosin responded to transmural electrical stimulation with frequency-related relaxations that were abolished by tetrodotoxin. The nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine (L-NNA) significantly attenuated but did not abolish the response; L-arginine reversed the inhibition. The neurogenic relaxation was not influenced in the strips treated with atropine or calcitonin gene-related peptide (CGRP)-(8-37), a CGRP-receptor antagonist, and those desensitized to vasoactive intestinal polypeptide (VIP) or pituitary adenylate cyclase-activating polypeptide (PACAP). Nerve fibers containing NADPH diaphorase were histochemically demonstrated in cavernous tissues. The relaxant response resistant to the NO synthase inhibitor was abolished by high K+ and tetrabutylammonium but was unaffected by glibenclamide, charybdotoxin, apamin, ouabain, SKF-525a, a cytochrome P-450 inhibitor, and oxyhemoglobin. It is concluded that neurogenic relaxations of monkey corpus cavernosum muscle is associated partly with NO released as a neurotransmitter and that other relaxing factor(s) possibly responsible for K+ channel opening also participates; however, the type of K+ channel involved is not determined. Acetylcholine, VIP, CGRP, PACAP, and the Na+ pump do not seem to be involved in the neurogenic relaxation.

Animals↗

Cholinergic nerve function in monkey ciliary arteries innervated by nitroxidergic nerve.

We sought to determine the control of ciliary arterial tone by neurogenic acetylcholine (ACh) acting directly on smooth muscle and in conjunction with vasodilator nerves. Isolated posterior ciliary arteries from monkeys responded to ACh (10(-8)-10(-5) M) with dose-related contractions, which were endothelium independent. The response was not affected by cyclooxygenase inhibitors but was abolished by atropine. Relaxations induced at 10(-4) M ACh in the atropine-treated arterial strips were abolished by hexamethonium and NG-nitro-L-arginine (L-NNA), and L-arginine (L-Arg) reversed the response suppressed by L-NNA. Similar results were also obtained on the nicotine (10(-4) M)-induced relaxation. Contractions due to transmural electrical stimulation in the endothelium-denuded strips treated with L-NNA were potentiated by physostigmine and depressed by atropine; the remaining contraction in the presence of atropine was abolished by prazosin. Relaxations associated with electrical stimulation, sensitive to tetrodotoxin, were abolished or reversed to contractions by L-NNA and restored by L-Arg. Stimulation-induced relaxation was attenuated by exogenous ACh and physostigmine and was potentiated by atropine. ACh did not affect the relaxation caused by nitric oxide (NO). Nerve fibers and bundles containing NADPH diaphorase and acetylcholinesterase were histologically demonstrated in the adventitia of ciliary arteries. We conclude that 1) endogenous and exogenous ACh contracts monkey ciliary arteries by acting on muscarinic receptors in smooth muscle cell membranes, 2) vasodilatation elicited by nerve stimulation with electrical pulses or nicotine is mediated by NO synthesized from L-Arg, 3) neurogenic ACh seems to interfere with the nitroxidergic nerve function by acting on prejunctional muscarinic receptors, and 4) high concentrations of ACh stimulate nicotinic receptors in vasodilator nerve terminals and promote the synthesis and/or release of NO.

Acetylcholine↗

Asymptomatic intrarenal arteriovenous fistula accompanying severe renal vein dilatation detected 30 years after percutaneous renal biopsy.

We report on a patient with asymptomatic intrarenal arteriovenous fistula (AVF) accompanying severe renal vein dilatation detected 30 years after percutaneous renal biopsy. The patient was found to have microscopic hematuria. Three-dimensional computerized tomography confirmed the presence of an AVF, and arterial embolization was performed. Three-dimensional computerized tomography is very useful and effective to image the physiology of vascular lesions for the diagnosis of a renal AVF.

Angiography↗

Gelatinous bone marrow transformation complicated by self-induced malnutrition.

A 48-year-old woman with a history of anorexia nervosa was admitted to our hospital because of malaise, anorexia and edema in the face and legs. She was diagnosed with gelatinous bone marrow and iron deficiency anemia due to severe malnutrition. She was intravenously treated by saccharated ferric oxide and her anemia was improved, but her bone marrow still showed much gelatinous material.

Anorexia Nervosa↗

Cerebral vasodilators.

The vascular tone, vascular resistance and blood flow in the brain are regulated by neural and humoral factors in quite a different way from those of peripheral organs and tissues. In contrast to the dominant vasoconstrictor control in the periphery, the intracranial vascular tone is predominantly influenced by vasodilator mediators over vasoconstrictor ones. Recent studies have revealed that nitroxidergic vasodilator nerve and endothelium-derived hyperpolarizing factor (EDHF) or K+ channel opening substance appear to play important roles in the regulation of cerebral arterial and arteriolar tone in primate and subprimate mammals, in addition to the accepted information concerning the crucial contribution of endothelium-derived relaxing factor (EDRF) or nitric oxide (NO), polypeptides, prostanoids, etc. This article summarizes characteristic properties of vasodilator factors in controlling the cerebral arterial and arteriolar tone that undoubtedly contribute to circulatory homeostasis. The content includes vasodilator nerve, endogenous vasodilator substances, and vasodilator interventions such as hypoxia, hypercapnia and hyperosmolarity.

Animals↗

Functional studies on blockade by neosurugatoxin of nicotinic receptors in nitroxidergic and sensory nerve terminals and intramural ganglionic cells.

In isolated canine cerebral and cutaneous arteries and duodenum, effects of neosurugatoxin (NSTX) on the response to nicotine were compared. Nicotine-induced relaxations are mediated by nitric oxide (NO) from vasodilator nerves in cerebral arteries and by calcitonin gene-related peptide (CGRP) in cutaneous arteries treated with NO synthase inhibitors. Duodenal relaxation to nicotine is mediated by NO from inhibitory nerves. Cerebral arterial strips without endothelium responded to nicotine with relaxations that were inhibited by NSTX (3 x 10(-10) to 3 x 10(-9) M) concentration-dependently. Relaxations to nicotine of duodenal strips were attenuated by NSTX and abolished by tetrodotoxin, whereas those induced by K+ and electrical stimulation were not influenced. In cutaneous arteries treated with N(G)-nitro-L-arginine, nicotine-induced relaxations were attenuated by NSTX as low as 10(-10) M, but unaffected by tetrodotoxin. The inhibitory potency of NSTX was in the order of cutaneous artery > duodenum > cerebral artery. It is concluded that NSTX selectively antagonizes actions on nicotinic receptors in nitroxidergic nerves of cerebral arteries, CGRP-mediated sensory nerves of cutaneous artery and ganglionic cells of the duodenum, but the affinity of this toxin to nicotinic receptors in sensory nerves is the highest.

Animals↗

Decrease in glomerular filtration rate in Japanese patients with type 2 diabetes is linked to atherosclerosis.

OBJECTIVE: We assessed the effects of atherosclerosis on the glomerular filtration rate (GFR) in patients with type 2 diabetes and who had micro- or normoalbuminuria. RESEARCH DESIGN AND METHODS: A total of 61 Japanese patients with type 2 diabetes were recruited from inpatients of Osaka City University Hospital. They ranged in age from 40 to 69 years (28 men and 33 women). Each subject collected a 24-h urine sample for quantitative analysis of albumin. Absence of albuminuria was defined as a urinary albumin excretion level of <30 mg/24 h (n = 36) and microalbuminuria as a level of 30-300 mg/24 h. The GFR was estimated using 99mTc diethylenetriamine pentaacetic renogram method. As indexes of atherosclerosis, we measured the intimal-medial thickness (IMT) and distensibility of the carotid artery using high-resolution B-mode ultrasonagraphy and an echo-tracking system. We measured the resistance index (RI) of the renal interlobar arteries by pulsed Doppler sonography. RESULTS: The clinical characteristics of type 2 diabetic patients with and without microalbuminuria did not differ except for duration of diabetes, which was longer in the patients with microalbuminuria. GFR also did not differ between the patients with and without microalbuminuria. GFR was significantly correlated with the patient's age (r = -0.256, P < 0.05), carotid IMT (r = -0.326, P < 0.05), carotid stiffness beta (r = -0.449, P < 0.001), and renal arterial RI (r = -0.365, P < 0.05). In multiple regression analysis, independent factors associated with GFR were carotid IMT (R2 = 0.108, P = 0.0102), carotid stiffness beta (R2 = 0.208, P = 0.0003), and renal artery RI (R2 = 0.130, P = 0.0043). CONCLUSIONS: The decline in GFR in type 2 diabetic patients in the early stages of nephropathy may be due in part to atherosclerosis.

Adult↗

Aspartate dehydrogenase in vitamin B12-producing Klebsiella pneumoniae IFO 13541.

We found a new reaction of aspartic acid dehydrogenation, catalyzed by NADP(+)-dependent aspartate dehydrogenase, in vitamin B12-producing Klebsiella pneumoniae IFO 13541. The enzyme, which was purified from a crude extract of K.pneumoniae IFO 13541, catalyzes the oxidative deamination of aspartic acid to form oxaloacetic acid. This enzyme had a molecular mass of about 124 kDa consisting of two identical subunits. L-Aspartic acid was a substrate, although D-aspartic acid and L-glutamic acid were inactive. The enzyme showed maximal activity at about pH 7.0-8.0 for the oxidative deamination of L-aspartic acid, and it required NADP+ as a coenzyme, while NAD+ was inactive.

Amino Acid Oxidoreductases↗

[Pneumoperitoneum with systemic sclerosis].

We report a case of systemic sclerosis (SSc) complicated with benign pneumoperitoneum without apparent pneumatosis cystoides intestinalis (PCI). A 43-year-old woman was admitted to our hospital because of prominent abdominal distension in April 1997. Raynaud's phenomenon has been detected since 1991. She was suffering from recurrent diarrhea, constipation, and subileus. The diagnosis of SSc was made in 1996 based on the sclerosis in her face, forearms, and chest, and hypomotility of the esophagus. On admission, she presented no signs of peritoneal irritation. The laboratory data revealed that white blood cell count was 7,400/mm3 and C-reactive protein was 0.1 mg/dl. Chest and abdominal roentgenograms showed massive free air under the diaphragm, dilatation of small and large intestine, and air-fluid level. PCI was not apparent. Pneumoperitoneum was improved after four weeks with intravenous hyperalimentation. But she presented recurrent severe diarrhea and high fever whenever she tried to take food orally. Klebsiella pneumoniae was proved in her jejunal juice by bacteriologic examination. Intravenous prostaglandin F2 alpha and oral fosfomycin calcium intake made her condition better. Benign pneumoperitoneum without PCI is rarely reported in the patients with SSc. In her condition, weakness of intestinal wall, hypomotility of intestine, unusual bacterial overgrowth, and elevated intraluminal pressure made intraluminal gas go through the wall of the fragile intestine of SSc. As operation of intestine of SSc usually cause miserable outcome, pneumoperitoneum accompanied with SSc even if PCI is apparent or not must be treated with conventional manner while there is no signs of peritoneal irritation.

Adult↗

[A comparative study of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET: visual and quantitative evaluation].

UNLABELLED: We compared the results of visual and quantitative evaluation of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET in the 7 non-myocardial infarction (non-MI) and 42 myocardial infarction (MI) patients. On the 201Tl-SPECT and 13NH3-PET imaging, the degree of accumulation of each radioisotope (RI) was visually classified into four grades of defect score. The percentage of uptake was also quantitatively evaluated. RESULTS: In the 7 non-MI patients, NH3% uptake in the lateral wall was significantly lower than in the septum, and in the lateral wall NH3% uptake was significantly lower than Tl% uptake. For the 42 MI patients, segmental defect scores (DS) on 201Tl-SPECT were compared with those on 13NH3-PET, and a high degree of concordance in DS was found for all territories of the left ventricle, antero-septum MI and inferior MI territories. Average Tl% uptake/NH3% uptake was near 1, a highly positive correlation was found between Tl% uptake and NH3% uptake in all territories of the left ventricle and antero-septum MI territories, and Tl% uptake/NH3% uptake was larger than 1, but, a significant positive correlation existed between Tl% uptake and NH3% uptake in the territory with inferior MI. CONCLUSION: These findings indicate that results of 201Tl-SPECT imaging were similar to those of 13NH3-PET in evaluation of myocardial perfusion in the antero-septum and inferior. However, a difference in distribution was observed between 201TlCl and 13NH3 in the lateral wall, indicating that particular attention should be paid to the results of imaging of myocardial perfusion in the lateral wall.

Aged↗