Search PubMed⌕ Search

Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 703 records · Page 39Linked to original sources
PubMed1995

Expression of monocyte chemoattractant protein-1 in vascular tissue.

We investigated monocyte chemoattractant protein-1 (MCP-1) mRNA expression in rat vascular smooth muscle cells (VSMC) and in human atherosclerotic arteries to test the involvement of MCP-1 in the pathogenesis of atherosclerosis. In Northern blot analysis, MCP-1 mRNA expression was not observed in unstimulated cultured rat vascular smooth muscle cells (VSMC), but its expression was clearly observed by exposure to tumour necrosis factor-alpha (100 U/ml) for 2-6 h. Mitogen-activated protein kinase activity in VSMC incubated in serum-free culture medium was increased by exposure to 0.5% fetal bovine serum, while the effect was significantly suppressed in the presence of MCP-1 (100 ng/ml). We then evaluated MCP-1 mRNA expression in atherosclerotic arteries obtained from 12 patients undergoing bypass revascularization through reverse transcription-polymerase chain reaction analysis and observed MCP-1 mRNA expression in all atherosclerotic arteries studied. These results support the premise that MCP-1 is secreted by VSMC in atherosclerotic plaques as well as by endothelial cells and macrophages and contributes to the pathogenesis of atherosclerosis.

Animals↗
PubMed1995

Regionalized gene expression of prolactin and growth hormone in the chicken anterior pituitary gland.

Messenger ribonucleic acid (mRNA) levels of PRL and GH in perifused cephalic and caudal lobes of the anterior pituitary gland of the chicken were determined by Northern blot analysis and are related to hypothalamic peptide perifusion. Perifusion of vasoactive intestinal peptide (VIP, 10 and 100 nM) significantly increased both PRL secretion and levels of PRL mRNA in the cephalic lobe, whereas no effects of VIP were observed in the caudal lobe. In contrast, growth hormone-releasing factor (GRF) (1-100 nM) did not induce an increase in either GH secretion or levels of GH mRNA in the cephalic lobe but did increase GH secretion and levels of GH mRNA in the caudal lobe. In addition, forskolin perifusion increased secretion and levels of PRL and GH mRNA in both cephalic and caudal lobes, respectively. These results indicate that gene expression of PRL and GH in response to VIP and GRF, respectively, is localized to specific lobes of the anterior pituitary gland, but that they may share, in part, a common second messenger pathway, namely, cAMP.

Animals↗
PubMed1995

Effects of presence of an egg and calcium deposition in the shell gland on levels of messenger ribonucleic acid of CaBP-D28K and of vitamin D3 receptor in the shell gland of the laying hen.

Levels of calbindin-D28K (CaBP-D28K) mRNA and vitamin D3, 1 alpha, 25(OH)2D3, receptor (VDR) mRNA in the intestine and shell gland were measured in the laying hen during the ovulatory cycle by Northern and slot blot analyses. In addition, effects of presence of an egg and calcium deposition in the shell gland on the levels of both mRNAs were studied either by delay in oviposition (retaining the egg in the shell gland beyond the expected time of oviposition) or premature oviposition (emptying the shell gland and arrest of calcium deposition). During the ovulatory cycle mRNA levels of CaBP-D28K and of VDR remained relatively constant in the intestine. In contrast, both mRNA levels of the shell gland were low when there was an egg in the infundibulum, magnum, and isthmus, but significantly increased when there was an egg in the shell gland during shell formation. The im injection of indomethacin 3 hr before expected ovulation delayed oviposition but increased neither shell thickness nor mRNA levels of CaBP-D28K and of VDR. On the other hand, premature oviposition reduced mRNA levels of both CaBP-D28K and VDR in the shell gland. These results suggest that the presence of an egg and calcium deposition in the shell gland may be a stimulatory factor for synthesis and accumulation of CaBP-D28K mRNA and VDR mRNA in association with calcification.

Animals↗
PubMed1995

Activated (HLA-DR+) T-lymphocyte subsets in early epithelial ovarian cancer and malignant ovarian germ cell tumors.

We examined peripheral blood T-lymphocyte subsets before initiation of therapy in 79 healthy controls, 3 patients with endometriosis, 95 patients with common epithelial tumors of the ovary, 15 patients with ovarian germ cell tumors, and 3 patients with ovarian sex cord-stromal tumors. In stage Ia/Ib patients with epithelial ovarian cancer, the percentages of activated CD4+ (CD4+HLA-DR+) T cells and activated CD4+ T cells in the CD4+ T-cell subsets were significantly higher than those of healthy controls and patients with benign or borderline epithelial tumors of the ovary. These immunologic parameters were subsequently decreased in patients in stage Ic and more advanced stages. In malignant ovarian germ cell tumors, a similar increase in the CD4+ T-cell subsets was observed. Moreover, the percentage of activated CD8+ T cells in the CD8+ T-cell subsets in stage Ia/Ib patients increased significantly compared with those in healthy controls and patients with benign tumors. Our findings indicate that activated T lymphocytes may play some roles in oncogenesis and progression of both epithelial ovarian cancer and malignant ovarian germ cell tumors.

CD4-Positive T-Lymphocytes↗
PubMed1995

KatG sequence deletion is not the major cause of isoniazid resistance in Japanese and Yemeni Mycobacterium tuberculosis isolates.

One of the mechanisms of isoniazid resistance to Mycobacterium tuberculosis has been proved to be the chromosomal deletion of katG. Based on this finding, 22 isoniazid-resistant isolates of M. tuberculosis obtained in Japan and Yemen were analysed for katG by polymerase chain reaction and catalase activity. Only six (27%) of the 22 isolates were compatible with the mechanism (lack of amplification of katG and loss of catalase activity). In contrast, eight isolates (36%) were katG positive but catalase activity-negative and eight (36%) were positive for both factors, indicating that isoniazid resistance is multifactorial and the deletion of katG was not the major cause of resistance in the isolates examined in this study.

Bacterial Proteins↗
PubMed1995

Cardiac electrophysiologic effects of parathyroid hormone in the guinea pig.

The cardiac electrophysiologic effects of parathyroid hormone (PTH) were studied in three different experimental models. Purified synthetic human parathyroid hormone (hPTH 1-84), at a dose of 30 ng/g body weight (BW), prolonged the QT interval of surface ECGs in intact guinea pigs. To further clarify the mechanisms of the QT prolongation caused by hPTH, the action potentials of guinea pig papillary muscle were recorded by conventional microelectrode techniques. hPTH (10(-7)M) prolonged the action potential duration without changing the action potential amplitude, resting potential, maximal upstroke velocity of the action potential, or maximal repolarization rate. hPTH affected only the plateau phase, in a concentration-dependent fashion. The half-maximum concentration was 6.8 x 10(-8)M for action potential duration at 30% repolarization (APD30), 3.2 x 10(-8)M for APD50, and 2.1 x 10(-8)M for APD90. In isolated single guinea pig ventricular cells, the patch clamp method was used to record the slow inward calcium current (ICa) and delayed rectifier potassium current (IK) responsible for the action potential plateau phase. hPTH increased the peak amplitude of ICa at + 10mV by an average of 42%, and increased IK at + 10mV by 85%. These results indicate that, in ventricular muscle, hPTH prolongs the action potential duration and QT interval by the balance of the prolongation effect on APD by enhancing the slow inward calcium current and the shortening effect on APD by enhancing the delayed rectifier potassium current.

Action Potentials↗
PubMed1995

Gender differences of disturbed hemostasis related to fasting insulin level in healthy very elderly Japanese aged > or = 75 years.

We investigated the relationship between fasting insulin level and various hemostatic factors, including fibrinolytic factors (active plasminogen activator inhibitor-1 (PAI-1), tissue type plasminogen activator (tPA)-PAI-1 complex, plasmin-alpha 2-plasmin inhibitor (PIC), and D-dimer), coagulation factors (activated factor VII, factor VII coagulant activity and antigen, factor VIII, factor X, and fibrinogen), coagulation inhibitors (antithrombin III, heparin cofactor II, and protein C), and an acute phase marker (sialic acid) in 102 healthy individuals aged > or = 75 years (46 men and 56 women). Active PAI-1 levels had a significant negative correlation with PIC levels (r = -0.342, P = 0.0006), indicating that PAI-1 influences in vivo fibrinolytic activity in the very elderly. Gender differences were found in the relationship between insulin and hemostatic abnormalities, with the insulin level being positively correlated with coagulation factors in men (factor VIII activity: r = 0.422, P < 0.01; factor VII activity: r = 0.386, P < 0.01) and with hypofibrinolysis in women (active PAI-1: r = 0.549, P < 0.0001). Insulin levels were positively correlated with the levels of factor VII antigen and factor VII activity in men (P < 0.01), but there was no correlation with activated factor VII levels. The fasting insulin level was also correlated with the levels of heparin cofactor II and sialic acid in men (P < 0.05). However, other hemostatic factors were not related to the insulin level in either sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Expression of cytokine-induced neutrophil chemoattractant in rat cardiac myocytes.

Accumulation and adhesion of leukocytes to cardiac myocytes play important roles in the pathogenesis of inflammation-mediated myocardial injury such as ischaemia/reperfusion and myocarditis. The involvement of leukocyte chemotactic factors has been speculated in these processes. We investigated the expression of cytokine-induced neutrophil chemoattractant (CINC) in rat cardiac myocytes. CINC is a rat equivalent of human interleukin-8. On exposure to interleukin-1 alpha (IL-1 alpha), cultured neonatal rat cardiac myocytes released appreciable levels of CINC both dose- and time-dependently. Tumor necrosis factor-alpha and lipopolysaccharide also significantly increased CINC accumulation in the culture supernatant. CINC mRNA expression was not observed in unstimulated myocytes, however, the expression was markedly induced by exposure to IL-1 alpha with a peak elevation at 3 h. Potent chemotactic activity for neutrophils was detected in the supernatant of cultured rat cardiac myocytes by stimulation with IL-1 alpha. This IL-1 alpha-induced chemotactic activity was significantly inhibited by polyclonal anti-CINC antiserum. Addition of dexamethasone, genistein, actinomycin D or cycloheximide significantly suppressed the IL-1 alpha-induced CINC accumulation. Under hypoxia (95%N2 + 5%CO2), CINC accumulation was increased in a time-dependent manner, and reoxygenation after hypoxia further intensified CINC accumulation. This hypoxia reoxygenation-induced CINC expression was significantly inhibited by pretreatment with dexamethasone. In conclusion, inflammatory stimuli induce the expression of CINC in rat cardiac myocytes, which may lead to myocardial injury via accumulation and activation of neutrophils.

Animals↗
PubMed1995

Kissing aneurysms of distal anterior cerebral arteries demonstrated by magnetic resonance angiography.

BACKGROUND Multiple aneurysms, associated with distal anterior cerebral artery (ACA) aneurysm, are not rare; therefore, it is important to examine multiplicity of the aneurysms preoperatively. CASE REPORT A case of ruptured distal ACA aneurysm, associated with another one in a mirror position, is reported. A 43-year-old woman suffered subarachnoid hemorrhage. Conventional angiography demonstrated a saccular aneurysm on the bifurcation of the right or left distal ACA; however, magnetic resonance angiography (MRA) revealed two mirror-image aneurysms on both bifurcations. CONCLUSION MRA was useful for preoperative diagnosis of kissing aneurysms on distal ACAs.

Adult↗
PubMed1995

Localization of N-cadherin in the normal and regenerating nerve fibers of the chicken peripheral nervous system.

The localization of N-cadherin in the normal, and regenerating nerve fibers was investigated by immunocytochemistry in the chicken sciatic nerve. The normal unmyelinated fibers exhibited N-cadherin immunoreactivity on the plasma membranes of axons and Schwann cells where they were in contact with each other, while myelinated fibers displayed no immunoreactivity except at the mesaxon where Schwann cell plasma membranes were attached to each other. In the regenerating nerves, intense immunoreactivity was demonstrated on the surface of plasma membranes of axons and Schwann cells where axon-axon and axon-Schwann cell contacts were made. No immunoreactivity was observed on the plasma membranes where regenerating axons or Schwann cells were in touch with the basal lamina. In addition, it was revealed that some vesicles in the growth cones had distinct N-cadherin immunoreactivity at the inner limiting membrane surface. These findings indicate that N-cadherin may be involved in the axon-axon and axon-Schwann cell adhesion in the normal unmyelinated as well as regenerating nerve fibers, and also in the attachment of Schwann cell processes at the mesaxon of myelinated fibers. In addition, these findings suggest that N-cadherin might be, at least in part, supplied by fusion of growth cone vesicles with the surface plasma membranes in growing axons.

Animals↗
PubMed1995

Coagulation activity is increased in the left atrium of patients with mitral stenosis.

OBJECTIVES: This study investigated the hemostatic status of the right and left atria in patients with mitral stenosis. BACKGROUND: Systemic thromboembolism is a serious major complication in patients with mitral stenosis. However, the pathogenesis of thromboembolism in mitral stenosis is not fully understood. METHODS: We determined the plasma levels of biochemical markers for platelet activity (platelet factor 4 and beta-thromboglobulin) and status of thrombin generation (fibrinopeptide A and thrombin-antithrombin III complex) and fibrinolysis (D-dimer and plasmin-alpha 2-plasmin inhibitor complex) in specimens of blood obtained from the peripheral vein and right and left atria of 12 consecutive patients with mitral stenosis who were undergoing percutaneous mitral valvuloplasty. RESULTS: Plasma levels of platelet factor 4, beta-thromboglobulin, D-dimer and plasmin-alpha 2-plasmin inhibitor complex in the patients did not differ significantly between the right and left atria, whereas levels of fibrinopeptide A and thrombin-antithrombin III complex in the left atrium were significantly higher than those in the right atrium (fibrinopeptide A in the left and right atria 19.35 +/- 4.64 and 6.31 +/- 0.75 ng/ml [mean +/- SE], respectively, p < 0.02; thrombin-antithrombin III complex in the left and right atria 11.45 +/- 2.29 and 3.98 +/- 0.60 ng/ml, respectively, p < 0.01). Levels of fibrinopeptide A and thrombin-antithrombin III complex in the left atrium did not correlate with mean transmitral gradient, dimension of the left atrium or reciprocal of the mitral valve area. Peripheral blood plasma levels of von Willebrand factor antigen were significantly higher in the patients than in an age-matched control group of normal subjects (168 +/- 25% and 99 +/- 7%, respectively, p < 0.05) but showed no difference in the peripheral blood and right and left atria of the patients. CONCLUSIONS: The coagulation system is activated in the left atrium of patients with mitral stenosis even during anticoagulation.

Adult↗
PubMed1995

The coagulation system is activated in idiopathic cardiomyopathy.

OBJECTIVES: We investigated the plasma levels of molecular markers for platelet activity and the thrombotic and fibrinolytic status in patients with hypertrophic cardiomyopathy and dilated cardiomyopathy to determine the activating site of coagulation in these disorders. BACKGROUND: A thromboembolic event is a serious complication in patients with idiopathic cardiomyopathy. However, the activating site of the coagulation system in idiopathic cardiomyopathy has not been fully investigated. METHODS: We determined the plasma levels of molecular markers for platelet activity (platelet factor 4 and beta-thromboglobulin), thrombotic status (fibrinopeptide A and thrombin-antithrombin III complex) and fibrinolytic status (D-dimer and plasmin-alpha 2-plasmin inhibitor complex) in 13 patients with hypertrophic cardiomyopathy, 17 patients with dilated cardiomyopathy and 20 normal subjects. RESULTS: Plasma levels of platelet factor 4, beta-thromboglobulin and plasmin-alpha 2-plasmin inhibitor complex did not differ significantly among the three groups, whereas plasma levels of fibrinopeptide A and thrombin-antithrombin III complex in both patient groups were significantly higher than those in normal subjects. Plasma levels of D-dimer in patients with dilated cardiomyopathy were significantly higher than those in patients with hypertrophic cardiomyopathy and normal groups. In patients with hypertrophic cardiomyopathy, both fibrinopeptide A and thrombin-antithrombin III complex levels were significantly correlated with left atrial diameter. In patients with dilated cardiomyopathy, fibrinopeptide A and thrombin-antithrombin III complex levels showed a positive correlation with left ventricular end-diastolic volume and a negative correlation with fractional shortening of the left ventricle. CONCLUSIONS: The activated coagulation system in patients with hypertrophic and dilated cardiomyopathy may be triggered by left atrial dilation in hypertrophic cardiomyopathy and left ventricular enlargement and dysfunction in dilated cardiomyopathy.

Antifibrinolytic Agents↗
PubMed1995

A survey on surgeons' attitudes and practices in the care of HIV-infected patients in Japan.

We conducted a survey to learn surgeons' attitudes and practices concerning HIV-infected patients in Japan. We mailed questionnaires to 174 general hospitals and received responses from 126 (72.6%). Concerning preoperative HIV testing, 41% of the hospitals had never performed it. Twenty-nine percent had operated on at least one HIV-infected patient and 144 HIV-infected patients have received surgery under spinal, epidural or general anesthesia. During surgery, 6 accidental needlesticks occurred, but fortunately no seroconversion has been reported since the accidents. Therefore widerspread use of barrier precautions should be undertaken during surgical intervention. This survey revealed that 40-60% of the hospitals coped inadequately with such surgery. Therefore it is important to arrange a system in Japan so that HIV-infected patients will be able to receive necessary surgical treatment. For that purpose, a medical educational program for health care professionals is needed, because not only surgeons but all health care professionals in hospitals should be able to take part in the treatment of HIV-infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Tandem immunoaffinity chromatography for plasma 1 alpha,25-dihydroxyvitamin D3 utilizing two antibodies having different specificities: a novel and powerful pretreatment tool for 1 alpha,25-dihydroxyvitamin D3 radioreceptor assays.

We report here a novel and powerful pretreatment method for radioreceptor assays (RRAs) for human plasma 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) based on "Tandem" immunoaffinity chromatography (Tandem IAC). Two antibodies having different specificities were each immobilized on agarose gel with cyanogen bromide to produce immunosorbents which were stable and repeatedly usable. An ethyl ether extract of plasma was applied to the first affinity column, from which 1,25(OH)2D3 could be preferentially eluted and separated from 1 alpha-deoxy type metabolites. The effluent was then submitted to the second column, and the 1,25(OH)2D3 retained was eluted after non- or weakly-absorbed interfering substances were washed out. This procedure allowed efficient purification without careful handling or strict time-management in the entire operation and enabled avoiding preparative high-performance liquid chromatography (HPLC) from RRA even with a conventional chick intestinal vitamin D receptor. Mean (+/- SD) plasma 1,25(OH)2D3 values of 56 normal subjects and 10 patients with chronic renal failure, obtained with this Tandem IAC/RRA system, were 36.4 (8.7) and 11.2 (4.0) pg/ml, respectively. The Tandem IAC will also be useful for developing immunoassays or gas chromatography-mass spectrometry of 1,25(OH)2D3.

Adult↗
PubMed1995

Sequential MRI studies in patients with cervical cord injury but without bony injury.

Sequential magnetic resonance imaging (MRI) of 23 patients who suffered cervical spinal cord injury without bony injury was performed prospectively. The major cord injury detected by MRI was at the C3-4 disc level in 16 patients (70%). Three patterns of signal changes were observed. Enhancement of the injured cord was observed on Gd-DTPA-enhanced MRI in 10 patients and the palsy of these patients was more severe than that of those without enhancement. Enhancement was recognized about 2 weeks earlier than the signal change (from isointense to low intensity) on T1-weighted images. This enhancement might represent necrosis, absorption, and reorganisation of the spinal cord, and appears to be a sign of a poor prognosis or an indication that damage is permanent. Another characteristic imaging finding was a vague high intensity signal in the dorsal column of the spinal cord extending rostrally from the main lesion, which appeared 2-3 months after injury and disappeared around 6 months. This finding represents Wallerian degeneration of the corticospinal tract in the cervical cord. Rigidity of the legs and sensory changes of the fingers became more prominent during this period.

Adult↗
PubMed1995

Separation and characterization of 25-hydroxyvitamin D3 3-sulfate in human plasma by high-performance liquid chromatography.

The separation and characterization of 25-hydroxyvitamin D3 3-sulfate in human plasma are carried out by high-performance liquid chromatography. The vitamin D sulfate fraction is obtained from a plasma specimen (three volunteers) by the combined use of a Sep-Pak C18 cartridge, for solid-phase extraction, and a lipophilic gel (piperidinohydroxypropyl Sephadex LH-20), for ion-exchange chromatography. 25-Hydroxyvitamin D3 3-sulfate is identified in the examined three specimens in two ways: its chromatographic behavior and that of its fluorescent labeled derivative using 4-[4-(6-methoxy-2-benzoxazolyl)phenyl]-1,2,4-triazoline-3,5- dione; and data obtained from the solvolysis reaction.

Calcifediol↗