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Biomedical subjects

K Seki

Publications and source records attributed to K Seki.

At least 181 records · Page 10Linked to original sources
PubMed1996

[Aortic root replacement employing Cabrol and Piehler techniques].

Between February, 1982, and September, 1994, 24 patients underwent aortic root replacement using a valve-bearing composite graft and coronary perfusion grafts. The indications for surgery were annulo-aortic ectasia in 21 patients, and aortic dissection associated with significant aortic regurgitation in 3 patients. Aortic root was reconstructed employing the techniques described by Cabrol and colleagues (Cabrol operation) in 16, and by Piehler and Pluth (Piehler operation) in 8. Two of 16 patients who underwent Cabrol operation required concomitant procedures. Four patients (25.0%) who underwent Cabrol operation had technical troubles relating to coronary reattachements (kinking and torsion of coronary grafts in 2, obstruction of left limb of coronary graft in 1, and coronary graft compression by aortic wall wrapping in 1), while one patient (12.5%) having Piehler operation had coronary graft compression by partial wrapping of aortic root. The hospital deaths occurred in 4 patients undergone Cabrol operation, with the hospital mortality rate being 16.7%. Three patients including 2 with concomitant procedures died of low cardiac output and one died of rupture of residual dissecting aneurysm of the aortic arch. No pseudoaneurysm nor anastomotic stenosis was observed in any hospital survivors. Late deaths occurred in 5 patients, in whom there was no late complication relating to coronary reconstruction. However, late obstruction of left ostial stenosis developed in one patient who underwent Piehler operation, which required coronary artery bypass. We conclude that aortic root replacement using coronary perfusion grafts provides sound coronary anastomoses without late pseudoanurysm. Coronary reattachments is facilitated by use of Piehler technique, preventing coronary graft kinking or torsion. Late coronary ostial stenosis should be considered as a possible cause of fatal myocardial infarction and sudden death, and careful follow-up is required for patients having these kinds of operation for the prevention of late cardiac events.

Adult↗
PubMed1996

[A new quantitative assay of heat shock protein 70 by based on an enzyme-linked immunosorbent assay method].

Heat Shock Protein 70 (HSP70) was very important stress protein. HSP70 had been detected by immunoblotting or mRNA of HSP70. Our purpose is to develop an easy quantitative assay of HSP70 and utilize clinical samples, cells, tissues etc. We examined a new quantitative assay of HSP70 that was based on an enzyme-linked immunosorbent assay (ELISA). This quantitative assay showed reproducible standard curve, high reproducibility (CV : 7.1, 6.8%) and recovery (93 approximately 116%). The determination of HSP70 in human umbilical vein endothelial cells (HUVEC) by heat stress was assayed using this method. HSP70 in HUVEC increased according to the heat temperature. It is concluded that the quantity of HSP70 might be possible even in cells and tissues by this method.

Endothelium, Vascular↗
PubMed1996

Lung cancer-reacting human recombinant antibody AE6F4: potential usefulness in the sputum cytodiagnosis.

Human monoclonal antibody (hMAb) AE6F4 has been shown to be potentially useful for immunocytological detection of lung cancer cells in sputum. By recombinant DNA technology, IgM type hMAb AE6F4 was switched to lgG. The IgG mimic recombinant AE6F4 antibody expression plasmid was assembled using the antibody heavy chain gene, which ligated the gene encoding VH and CH1(mu) domains of hMAb AE6F4 heavy chain to the gene encoding CH2(gamma 1) and CH3(gamma 1) domains of human IgG heavy chain, and the antibody light chain gene of hMAb AE6F4. The recombinant antibody expressed by baby hamster kidney (BHK)-21 cells showed molecular size equivalence to IgG, and consisted of human mu-gamma hybrid heavy and kappa light chains. The immunological specificity of the recombinant antibody was the same as that of hMAb AE6F4 by immunoblotting analysis to the 14-3-3 protein, the putative antigen of hMAb AE6F4, and by immunohistochemical and immunocytological analyses using tissue sections and sputa of lung cancer patients. The transfected BHK-21 cells produced the recombinant antibody persistently and the productivity was greater than 20 times that by human-human hybridoma producing hMAb AE6F4.

14-3-3 Proteins↗
PubMed1996

Neuromagnetic evidence that the P100 component of the pattern reversal visual evoked response originates in the bottom of the calcarine fissure.

Visual evoked magnetic fields due to pattern reversal stimuli were measured in 5 normal subjects using a helmet-shaped 66 channel magnetoencephalography system linked to MRI. The magnetic topography of the prominent 100 ms response (P100m) evoked by fullfield visual showed a double-dipole pattern in the occipital areas of all subjects. Right or left half-field stimuli and upper or lower quadrant-field stimuli evoked a single-dipole pattern in the contralateral occipital area. The P100m sources were then localized using a current dipole model and superimposed on MRI images of each subject. The visual cortex was morphologically variable among the subjects, but the P100m dipoles were all localized at the lateral bottom of the calcarine fissure. Moreover, these P100m dipoles had similar orientations for both half-or quadrant-field stimuli. These results suggest that the P100m is located in a smaller part of the striate cortex than previously reported.

Adult↗
PubMed1996

Clinical application of visual evoked fields using an MRI-linked whole head MEG system.

We have demonstrated anatomo-functional correlation of the brain visual function using an MRI-linked whole-head magnetoencephalography system. Visual evoked magnetic fields (VEFs) due to pattern reversal stimuli were measured in seven healthy subjects and 13 patients with intracranial structural lesions. Full-field stimuli evoked the most prominent peak around 100 ms latency (P100m) as a two-dipole pattern over the occipital area in all of the normal subjects and four patients with mild and partial hemianopsia. In five patients with homonymous hemianopsia due to unilateral occipital lesion, a single-dipole pattern of the P100m appeared over the normal occipital area only. In four patients with bitemporal hemianopsia due to pituitary tumors, a single-dipole pattern of the P100m appeared only over the ipsilateral occipital area to the stimulated eye. Using current dipole models, P100m sources were localized at the lateral bottom of the calcarine fissures. Although human occipital lobes are known to be morphologically variable, our results indicate excellent correlation of the cortical anatomy and human visual function. Full-field stimuli, requiring no strict visual fixation, are especially useful for clinical application. A clear two-dipole pattern in the normal VEFs enables us to compare two hemispheric activities.

Adult↗
PubMed1995

Prognostic implication of the p53 protein and Ki-67 antigen immunohistochemistry in malignant fibrous histiocytoma.

BACKGROUND: Mounting evidence indicates that p53 regulates cell growth and abnormal p53 immunophenotypic expression is associated with an unfavorable prognosis for patients with some types of carcinoma. The prognostic significance of p53 overexpression in malignant fibrous histiocytomas (MFHs) of soft tissue has not yet been elucidated. METHODS: Expressions of p53 protein and Ki-67 antigen in 54 primary MFHs of soft tissue were investigated immunohistochemically and indexed quantitatively by counting the number of immunoreactive nuclei versus the total neoplastic nuclei in the representative fields of each tumor to evaluate their prognostic implications and interrelations with other clinicopathologic parameters. RESULTS: The percentages (labeling indices [LIs]) of p53 and Ki-67-immunoreactive nuclei versus the total neoplastic nuclei were 0.1-93.2% (mean +/- standard deviation [SD], 40.6% +/- 21.8%) and 5.3-90.8% (mean +/- SD, 42.7% +/- 29.4%), respectively. The Ki-67 LI correlated with histologic grade (P = 0.01498), primary tumor size (P = 0.04985), disease free interval (reverse correlation, P = 0.00776), and recurrence and metastasis (P = 0.00360). The p53 LI correlated with primary tumor size (P = 0.00431) but did not show any significant correlation with histologic grade, Ki-67 LI, primary tumor size, disease free interval, or recurrence and metastasis. Other significant correlations included histologic grade and disease free interval (P = 0.00010), primary tumor size and disease free interval (reverse correlation, P = 0.00869), histologic grade and recurrence (P = 0.02714), and primary tumor size and primary tumor location (P = 0.00028). In the grouped survival analysis, patients with recurrence or metastasis or with tumors of larger size (> or = 7 cm), high histologic grade, or higher Ki-67 LI (> or = 25%) had a significantly reduced survival (P < 0.05). The different p53 immunohistochemical expression and the different histologic types did not reflect different cumulative survival (P > 0.05). Regression analysis revealed that the primary tumor size and histologic grade, but not Ki-67 or p53 LIs, were independent statistical variables for prognostication. CONCLUSIONS: These results indicate that (1) primary tumor size and histologic grade are two important prognostic factors, (2) Ki-67 LI should be used in adjunct with other main prognostic factors for patients with MFHs, and (3) nuclear p53 overexpression in MFHs of soft tissue is a comparatively common event that has no prognostic implication.

Adult↗
PubMed1995

Dephosphorylation of protein kinase C substrates, neurogranin, neuromodulin, and MARCKS, by calcineurin and protein phosphatases 1 and 2A.

Neurogranin, neuromodulin, and MARCKS are among the most prominent substrates of protein kinase C (PKC) in the mammalian brain. These phosphoproteins were dephosphorylated by three isoforms of rat brain calcineurin, also known as calmodulin (CaM)-dependent protein phosphatase (CaMPP). The three CaMPP isozymes dephosphorylate neurogranin, the most favorable substrate among the three tested, with subtle differences in their responses to divalent metal ions, Mn2+ and Ni2+. Dephosphorylation of neurogranin by all three CaMPP isozymes, CaMPP-1, -2, and -3, were stimulated to a higher extent by Mn2+ than by Ni2+ in the presence of CaM and Ca2+. The Km values of neurogranin in the presence of Mn2+ were lower than those in the presence of Ni2+ for CaMPP-1 and -2, but that for CaMPP-3 was comparable with either divalent metal ion. The Vmax values were higher in the presence of Mn2+ than those of Ni2+ for all three isozymes. Neurogranin and neuromodulin, both phosphorylated by PKC at a single site, were dephosphorylated completely by CaMPP; however, MARCKS, phosphorylated by PKC at three sites, was partially dephosphorylated by this phosphatase. A higher extent of dephosphorylation of MARCKS could be achieved by the combination of CaMPP and protein phosphatase 2A and a complete dephosphorylation of this protein was observed with protein phosphatase 1. Protein phosphatase 1 and 2A were also effective in a complete dephosphorylation of neurogranin and neuromodulin. Amino acid sequence analysis of the tryptic phosphopeptides derived from MARCKS dephosphorylated by CaMPP and protein phosphatase 2A revealed that the former preferentially dephosphorylated Ser155 and the latter Ser162 of rat brain MARCKS. Both phosphatases dephosphorylated poorly of Ser151. Because of the high concentration of CaMPP in the brain and the colocalization of this phosphatase with major PKC substrates in the various brain regions, it is likely that CaMPP is a phosphatase with potential to reverse the action of PKC.

Amino Acid Sequence↗
PubMed1995

Fine structural study of interstitial cells associated with the deep muscular plexus of the rat small intestine, with special reference to the intestinal pacemaker cells.

Two types of interstitial cells have been demonstrated in close association in the deep muscular plexus of rat small intestine, by electron microscopy. Cells of the first type are characterized by a fibroblastic ultrastructure, i.e. a well-developed granular endoplasmic reticulum, Golgi apparatus and absence of the basal lamina. They form a few small gap junctions with the circular muscle cells and show close contact with axon terminals containing many synaptic vesicles. They may play a role in conducting electrical signals in the muscle tissue. Cells of the second type are characterized by many large gap junctions that interconnect with each other and with the circular muscle cells. Their cytoplasm is rich in cell organelles, including mitochondria, granular endoplasmic reticulum and Golgi apparatus. They show some resemblance to the smooth muscle cells and have an incomplete basal lamina, caveolae and subsurface cisterns. However, they do not contain an organized contractile apparatus, although many intermediate filaments are present in their processes. They also show close contacts with axon terminals containing synaptic vesicles. These gap-junction-rich cells may be regular components of the intestinal tract and may be involved in the pacemaking activity of intestinal movement.

Animals↗
PubMed1995

Effect of arm cranking exercise on skin blood flow of lower limb in people with injuries to the spinal cord.

The purpose of this study was to examine whether arm cranking exercise induces changes in skin blood flow in the paralyzed lower limbs of people with injuries to the spinal cord (PISC). Ten PISC with lesions located between Th5 and L5 and six control subjects performed arm cranking exercise for 6 min at three intensities, 10, 30 and 50 W, at a room temperature of 25 degrees C. Oxygen uptake (Vo2) and heart rate (HR) were measured for the last 2 min of each exercise period. The skin blood flow at the anterior thigh (BFsk,t) was continuously monitored using laser Doppler flowmetry for the whole 6-min period and for the first 10 min of recovery following exercise. During exercise, the PISC showed lower Vo2 and greater HR than the control subjects. No increase in BFsk,t was found in six of the PISC with lesions at or above Th12, irrespective of the exercise intensity. On the other hand, in PISC with lesions at L1 or below, BFsk,t increased significantly (P < 0.05) with an increase in Vo2 and HR, although the BFsk,t at a given Vo2 and HR was lower than that in the control subjects. These results would suggest that arm exercise can promote the blood circulation in the skin of the lower limbs if the injury level is below L1.

Adult↗
PubMed1995

Effects of cueing on visuospatial processing in unilateral spatial neglect.

Patients with typical left unilateral spatial neglect bisected lines after cueing to the left end-point, the fixation point being monitored with an eye camera. They persisted with the point of initial fixation made after cueing and placed the mark there without searching leftwards again. The rightward shift of fixation to the initial point of fixation thus determined the location of the subjective midpoint. We consider that rightward attentional bias increased the amplitude of this shift that was planned on the basis of the perception of the whole line while cueing. This hypothesis may explain smaller but obvious rightward bisection errors found in the cueing condition.

Aged↗
PubMed1995

Regional diastolic function in effort angina pectoris: assessment with biplane left ventriculography.

To investigate left ventricular (LV) regional diastolic function in effort angina pectoris (AP), we performed left ventriculography in 14 patients with AP and isolated left anterior descending artery disease and in 9 normal subjects (N). LV volume (V), regional area (S) [anterior, apex, and inferior], and the first derivative of V and S (dV/dt, dS/dt) were derived from analysis of the left ventriculogram. Normalized peak filling rate (nPFR) and peak atrial filling rate (nPAFR) were derived from dV/dt. The ratio of filling volume to stroke volume during rapid filling and atrial contraction were defined as rapid filling fraction (RFF) and atrial filling fraction (AFF). Similarly, peak area changing rate (PACR), peak area changing rate during atrial contraction (PACRac), rapid area changing fraction (RACF), and atrial area changing fraction (AACF) were derived from S and dS/dt. We also calculated the time constant of LV relaxation (T), and LV global and regional compliance during atrial contraction [(dV/VdP)ac, (dS/SdP)ac]. The LV global diastolic function (T increases, nPFR decreases) was impaired in the angina patients. LV regional diastolic function (nPACR decreases, RACF decreases) was also impaired in the affected region of the AP group. While their rapid filling was impaired, nPACRac was maintained and AACF was increased in the affected region. Furthermore, nPACR and RACF each showed a significant inverse correlation with AACF in the anterior region [r = -0.57 (P < 0.01), r = -0.92 (P < 0.001)]. In the affected region of the patients with AP, (dS/SdP)ac was increased, but not significantly. Thus, LV global and regional diastolic functions were simultaneously impaired in patients with isolated left anterior descending artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effect of anaesthetic agents on the phagocytic function of human polymorphonuclear leukocytes through analysis with a phagocytic plaque method.

We examined the effects of the intravenous anaesthetic agents, thiamylal and ketamine, on the phagocytic function of polymorphonuclear leukocytes (PMN) in heparinized peripheral blood from healthy individuals using the phagocytic plaque method. Subclinical doses of thiamylal caused enhancement of the phagocytic activity of PMN and super-clinical doses of thiamylal inhibited phagocytic activity of PMN. Ketamine did not adversely affect phagocytic function at relevant therapeutic concentrations. The results presented in this manuscript indicate the phagocytic plaque method can provide a quantitative assessment of the phagocytic function of leukocytes. This method may prove useful in determining whether anaesthetic agents and other drugs adversely affect leukocyte function and hence help prevent the increased susceptibility to infection which can occur in anaesthetized patients. Conversely, the phagocytic plaque method may prove useful in the search for immune-enhancing drugs.

Adult↗
PubMed1995

Dacron coronary graft obstruction after composite graft replacement of aortic root.

Obstruction of the left coronary ostial anastomosis is a rare late complication after composite graft replacement of the ascending aorta and the aortic valve with separate Dacron coronary grafts. Intimal proliferation caused by the turbulent blood flow at this site may be the cause of the obstruction, which is considered a possible cause of late cardiac events such as sudden death and global myocardial infarction. We describe a case of tight stenosis at the left coronary ostial anastomosis in a 38-year-old woman with Marfan's syndrome who had undergone a composite graft replacement that employed separate Dacron coronary grafts.

Adult↗