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Biomedical subjects

M Abe

Publications and source records attributed to M Abe.

At least 415 records · Page 23Linked to original sources
PubMed1997

Identification of MAPKAPK homolog (MAPKAPK-4) as a myosin II regulatory light-chain kinase in sea urchin egg extracts.

We identified and cloned a homolog of mammalian mitogen-activated protein kinase-activated protein kinase (MAPKAPK)-2 and -3 from sea urchin, Hemicentrotus pulcherrimus. The obtained cDNA clone was composed of 350 amino acid residues which contain MAPK phosphorylation sites and the bipartite nuclear localization signal sites in its C-terminal domain. The clone showed 65.4 and 66.7% amino acid residue identity to human MAPKAPK-2 and -3, respectively. Phylogenetic analysis revealed that the homolog can be classified into a distinct group of MAPKAPK and, therefore, the identified homolog was designated as MAPKAPK-4. Biochemical characterization was performed using recombinant glutathione S-transferase (GST)-MAPKAPK-4 fusion protein. The protein kinase activity of GST-MAPKAPK-4 was activated by MAPK and this enabled the kinase to phosphorylate both glycogen synthase N-terminal peptide and the regulatory light chain of myosin II in vitro. Northern blot analysis showed that MAPKAPK-4 was expressed throughout the development of sea urchin embryos. These observations suggest that MAPKAPK-4 may play an important role in the regulation of myosin II activity during the development of sea urchin.

Amino Acid Sequence↗
PubMed1997

A Novel Numerical Analysis on Surface Charge Densities of an Amphoteric O/W-Type Microemulsion in the Presence of CaCl2 and/or AlCl3

The effect of pH on the surface charge density of the O/W-type microemulsion formed in solutions of an amphoteric surfactant, (N alpha , N alpha -dimethyl-N epsilon -lauroyllysine, DMLL)/n -octane/1-pentanol/CaCl2 or AlCl3 , has been investigated. A novel equation for the surface charge densities in the presence of a multivalent cation (Ca2+ and/or Al3+ ) has been derived taking account of the number of DMLL molecules bound to a multivalent cation (q ). By applying a numerical analysis of this equation, it is possible to determine the intrinsic binding constants (K ) of the multivalent cation and the monovalent anion to the hydrophilic groups of DMLL and the adsorption density (N ) of DMLL molecules on the oil/water interface. Furthermore, N has been found to show pH dependence. N has a maximum value around the isoelectric region (in particular, pH 5-7) of DMLL molecules in the presence of CaCl2 , whereas N increases with increasing pH in the presence of AlCl3 . The surfactant (DMLL) numbers per O/W-type microemulsion droplet, i.e., the aggregation numbers, are successfully obtained as a function of pH in the presence of CaCl2 and/or AlCl3 .

Journal Article↗
PubMed1997

Postoperative production of anti-donor antibody and chronic rejection in renal transplantation.

To study the relevance of anti-donor antibody (ADA) to chronic rejection in kidney transplantation, we retrospectively examined the long-term kinetics of ADA by flow cytometric analysis. Among 537 recipients who underwent living-donor kidney transplantation between 1986 and 1994, 29 patients with chronic rejection (CR group) and 33 patients with stable graft function (ST group) were randomly selected for analysis. Patient serum taken 1 or 2 days before transplantation, serum taken 1 month after transplantation, and the most current serum were analyzed for the presence of ADA to donor T and B cells. In the CR group, IgG antibody to donor B cells of the most current serum was positive in 25 of 29 patients, whereas it was positive in only 5 patients in the ST group P<0.001. The mean fluorescent intensity of the antibody was also significantly higher in the CR group than that in ST group P<0.01. In contrast, IgG antibody to donor T cells of the most current serum was positive in only five patients in the CR group. No significant difference was observed in the pretransplant and 1-month posttransplant sera between the CR and ST groups. We conclude that the posttransplant production of IgG antibody to donor B cells seemed to be highly relevant to chronic rejection.

Adolescent↗
PubMed1997

Clinical results of radiofrequency hyperthermia for malignant liver tumors.

PURPOSE: To evaluate thermometry and the clinical results of radiofrequency (RF) hyperthermia for advanced malignant liver tumors. METHODS AND MATERIALS: One hundred seventy-three patients with malignant liver tumors treated between 1983 and 1995 underwent hyperthermia. The 173 tumors consisted of 114 hepatocellular carcinomas (HCCs) and 59 non-HCCs (47 metastatic liver tumors and 12 cholangiocarcinomas). Eight-megahertz RF capacitive heating equipment was used for the hyperthermia. Two opposing 25-cm electrodes were generally used for heating the liver tumors. Our standard protocol was to administer hyperthermia 40-50 min twice a week for a total of eight sessions. The liver tumor temperature was measured by microthermocouples when possible. Transcatheter arterial embolization, radiotherapy, immunotherapy, and chemotherapy were combined with hyperthermia treatment in accordance with each patient's liver function. RESULTS: One hundred forty (81%) of the 173 patients who underwent more than four sessions of hyperthermia were evaluated in this study. Thermometry was performed in 77 (55%) of these 140 patients. The maximum tumor temperature, average tumor temperature, and minimum tumor temperature in the HCC were (mean +/- standard error) 41.2 +/- 0.2 degrees C, 40.3 +/- 1.3 degrees C, and 40.1 +/- 0.2 degrees C, respectively. The same thermometry results for non-HCC were 42.3 +/- 0.2 degrees C, 41.2 +/- 0.2 degrees C, and 40.9 +/- 0.2 degrees C, respectively. The maximum and minimum temperatures (41.8 +/- 0.2 degrees C and 40.3 +/- 0.4 degrees C) in the patients with a complete or partial response (CR or PR) were higher than those in the patients with no response or progressive disease (NR or PD) (41.3 +/- 0.5 degrees C and 39.8 +/- 0.4 degrees C), but the difference was not significant. Of the 73 cases with HCC who were evaluated by computed tomography (CT), CR was achieved in 7 (10%), PR in 15 (21%), NR in 37 (51%), and PD in 14 (19%). Of the 45 cases involving liver metastases evaluated by CT, CR was achieved in 3 (7%), PR in 17 (38%), NR in 12 (27%), and PD in 13 (29%). The 1-year cumulative survival rate for HCC patients was 30.0%, and the 5-year survival rate was 17.5%. The 1-year survival of non-HCC patients was 32.5%, and the longest survival was 30 months. The sequelae of hyperthermia included focal fat necrosis in 20 patients (12%), gastric ulceration in 4 (2%), and liver necrosis in 1 (1%). The sequelae of thermometry were severe peritoneal pain in seven patients (11%), intraperitoneal hematoma in one (1%), and pneumothorax in one (1%). CONCLUSION: Even though the thermometry results for liver tumors were not satisfactory, the treatment results are promising. Further clinical trials of RF capacitive hyperthermia for the treatment of advanced liver tumors should be encouraged.

Bile Duct Neoplasms↗
PubMed1997

The anti-human tumor effect and generation of human cytotoxic T cells in SCID mice given human peripheral blood lymphocytes by the in vivo transfer of the Interleukin-6 gene using adenovirus vector.

Interleukin-6 (IL-6) was found to function as a late-acting killer helper factor in the differentiation of CTLs. In the model of tumor-bearing mice, the systemic administration of recombinant IL-6 was found to mediate the antitumor effect on the immunogenic murine tumors via the in vivo induction of murine CTLs but not on the poorly immunogenic murine tumors in our previous study. However, an in vivo experimental model capable of analyzing the anti-human tumor effect via the in vivo induction of human CTLs has not yet been established. Therefore, in the present study, severe combined immunodeficient mice were given human peripheral blood lymphocytes (SCID-PBL/hu), and thereafter human tumor cells were administered i.p. into these SCID-PBL/hu mice as a model of human patients with cancer. When these SCID-PBL/hu mice bearing allogeneic human CESS B blastoid tumor cells were treated in vivo with recombinant adenovirus vector expressing IL-6 cDNA, both the induction of CD8+ human CTLs against CESS cells in the spleen cells and peritoneal exudate cells and a prolongation in the survival of these mice were observed. Furthermore, SCID-PBL/hu mice were given peripheral blood lymphocytes from patients with cancer (gastric or rectal cancers) and autologous human tumor cells. The in vivo administration of recombinant adenovirus vector expressing IL-6 cDNA induced CD8+ human CTLs specific for autologous human tumor cells from human precursor T cells. The in vivo injection of the IL-6 gene also inhibited growth and metastasis in autologous human cancers. Based on the above findings, the experimental model using SCID-PBL/hu mice and the IL-6 gene delivered in vivo by an adenovirus vector might therefore provide a new strategy capable of analyzing an anti-human tumor effect and the in vivo induction of human CTLs by cytokine gene therapy without using the human body.

Adenoviridae↗
PubMed1997

Nonsense mutation at Tyr-4046 in the DNA-dependent protein kinase catalytic subunit of severe combined immune deficiency mice.

The severe combined immune deficiency (SCID) mouse was reported as an animal model for human immune deficiency. Through the course of several studies, the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) gene came to be considered a candidate for the SCID-responsible gene. We isolated an ORF of the murine DNA-PKcs gene from SCID mice and their parent strain C.B-17 mice and determined the DNA sequences. The ORF of the murine DNA-PKcs gene contained 4128-aa residues and had 78.9% homology with the human DNA-PKcs gene. A particularly important finding is that a T to A transversion results in the substitution of termination codon in SCID mice for the Tyr-4046 in C.B-17 mice. No other mutation was detected in the ORF of the gene. The generality of this transversion was confirmed using four individual SCID and wild-type mice. The substitution took place in the phosphatidylinositol 3-kinase domain, and the mutated gene encodes the truncated products missing 83 residues of wild-type DNA-PKcs products. Furthermore, the quantity of DNA-PKcs transcript in wild-type and SCID cells was almost equal. These observations indicate that the DNA-PKcs gene is the SCID-responsible gene itself and that the detected mutation leads to the SCID aberration.

Amino Acid Sequence↗
PubMed1997

Evaluation of left atrial appendage function by measurement of changes in flow velocity patterns after electrical cardioversion in patients with isolated atrial fibrillation.

We investigated temporary changes in left atrial appendage (LAA) flow velocity patterns in patients undergoing electrical cardioversion for chronic isolated atrial fibrillation, and evaluated the role of active LAA contraction in directing blood flow to the left atrial main chamber and left ventricle. The study consisted of 26 patients with chronic isolated atrial fibrillation treated with electrical cardioversion and 20 normal controls in sinus rhythm. Using transthoracic and transesophageal Doppler echocardiography, we recorded transmitral, pulmonary venous, and LAA flow velocity patterns before, 24 hours, and 1 week after cardioversion in all subjects. In the 15 patients who underwent successful cardioversion, the maximal LAA area 24 hours after cardioversion was smaller than the area before cardioversion, whereas LAA ejection fraction during atrial systole and peak atrial systolic emptying velocity of the LAA flow were lower 24 hours after cardioversion than those in the control group. One week after cardioversion, maximal LAA area and LAA peak atrial systolic emptying velocity were restored to levels approximately equivalent to those in the control group, although LAA ejection fraction was lower than in the control group. Maximal LAA area and LAA peak atrial systolic emptying velocity correlated negatively and positively with LAA ejection fraction, respectively, 24 hours and 1 week after cardioversion. These results suggest that LAA and the left atrial main chamber show stunning 24 hours after cardioversion, and the atrial systolic emptying wave of LAA flow is generated by active LAA contraction.

Adult↗
PubMed1997

Mapping of a gene for the increased susceptibility of B1 cells to Mott cell formation in murine autoimmune disease.

Mott cells, a pathologic state of plasma cells containing intracellular inclusions of Igs (Russell bodies), are frequent in lymphoid tissues of murine and human autoimmune diseases. However, neither the genesis nor the significance of Mott cells in autoimmune diseases is well understood. We found that B1, but not B2, cells were induced in vitro to form Mott cells in the presence of LPS or IL-5, but not other stimulants, in a much higher frequency in autoimmune New Zealand Black (NZB) and NZB x New Zealand White (NZB/W) F1 than in non-autoimmune disease-prone mice and notably athymic nude NZB/W F1 mice. Cell surface phenotypes of Mott cells were B220+ CD5+ CD43+ CD11b(dull), while those of peritoneal macrophages were B220- CD5- CD43(dull) CD11b+. We mapped a locus (provisionally designated Mott-1) controlling Mott cell formation that was tightly linked to microsatellite marker loci, D4 Mit70 and D4 Mit48, of autoimmune NZB mice, which is in close proximity to our recently mapped locus Imh-1 for hypergammaglobulinemia. This region contains candidate genes that may be relevant to the aberrant B cell activation and differentiation. We suggest that while the Mott cell by itself is not the effector for autoimmune disease, the genetically determined aberrant maturational process of B1 cells that underlies the pathogenesis of autoimmune disease forms the basis for Mott cell formation in a T cell-dependent manner.

Animals↗
PubMed1997

Transesophageal pulsed Doppler echocardiographic evaluation of left atrial systolic performance in hypertrophic cardiomyopathy: combined analysis of transmitral and pulmonary venous flow velocities.

BACKGROUND: Hypertrophic cardiomyopathy (HC) is characterized by impaired left ventricular (LV) diastolic function due to an increase in LV wall thickness. The severity of this disease varies depending on the localization and extent of the hypertrophied myocardium and the presence and extent of myocardial disarray or fibrosis. HYPOTHESIS: The purpose of this study was to examine the background of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole in patients with HC using pulsed Doppler echocardiography. METHODS: Hemodynamic abnormalities between the left atrium and left ventricle during atrial systole were evaluated in patients with HC using transmitral flow (TMF) and pulmonary venous flow (PVF) velocities obtained by transesophageal pulsed Doppler echocardiography. The study population included 50 patients with HC, including 39 with asymmetric septal hypertrophy and 11 with apical hypertrophy, and showing fractional shortening of the left ventricle > or = 30%. They were classified into three groups: (1) Group A (n = 11): the ratio of the late to early TMF velocity < 1, and peak atrial systolic PVF velocity (PVA) < 25 mm/s; (2) Group B (n = 13): their ratio < 1, and PVA > or = 25 mm/s; and (3) Group C (n = 26): their ratio > or = 1. The mean age of patients in Group A was lower than that in Groups B and C. RESULTS: Left atrial dimension in Group B was significantly greater than that in the other HC groups and the control group. Furthermore, left atrial volume changes during atrial systole in Group B were significantly smaller than those in the other HC groups and the control group. Peak atrial systolic PVF velocity in Group B was significantly higher than that in the control group and in Group C. The duration of the atrial systolic waves of the TMF and PVF in Group B was significantly shorter and longer, respectively, than that in Group A. Left ventricular end-diastolic pressure (LVEDP) decreased in descending order with Group B > Group C > Group A. In all patients there was a significant positive correlation between the LVEDP and peak atrial systolic PVF velocity or the difference in duration between the atrial systolic waves of PVF and TMF. Plots of these values shifted toward the left and inferiorly in Group A, and toward the right and superiorly in Group B. CONCLUSION: Peak velocity and duration of TMF and PVF during atrial systole by transesophageal pulsed Doppler echocardiography are useful indices of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole, particularly a forceful atrial contraction mismatched to the left atrial afterload and severity of LV diastolic dysfunction, in HC.

Adult↗
PubMed1997

Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects.

BACKGROUND: It has become evident that mitral regurgitation (MR) is not uncommon in healthy subjects, and Doppler color flow mapping is a technique that imparts important information relevant to its detection. HYPOTHESIS: Using transthoracic echocardiography, this study evaluated the mechanism of physiologic MR in young normal subjects using transthoracic echocardiography. METHODS: The study population consisted of 48 young normal subjects (mean 21 +/- 5 years) with MR (physiologic MR group), 40 age-matched young normal subjects (mean 20 +/- 5 years) without MR (control group), 45 patients (mean 41 +/- 15 years) with mitral valve prolapse with MR (MVP group), and 27 patients (mean 59 +/- 13 years) with ruptured chordae tendineae (rupture group). RESULTS: Men were predominant in the rupture group, whereas there were no significant gender differences in the other three groups. Left ventricular end-diastolic dimension and left atrial systolic dimension were slightly smaller in the physiologic MR group than in the control group, but were significantly smaller than those in the MVP and rupture groups. The ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography and the ratio of the short- to long-axis diameter of the left ventricular cavity at end diastole, determined from two-dimensional short-axis echocardiogram, were significantly lower in the physiologic MR group than in the other three groups. Mitral regurgitation occurred more frequently at the posteromedial commissural site in the physiologic MR and MVP groups, whereas there was no preference for location in the rupture group. Early systolic MR was often observed in the physiologic MR group, whereas pansystolic MR was common in the MVP and rupture groups. CONCLUSION: As a causal mechanism for physiologic MR detected in young normal subjects, "flattening" of the thorax during growth may cause morphologic abnormalities of the left atrial and ventricular cavities, resulting in spatial imbalance of the mitral complex and resulting in malcoaptation of the valve.

Adult↗
PubMed1997

Surgical removal of cavernous angioma in the medulla oblongata. A case report.

Recent advances in neuroradiology have enabled us to approach cavernous angioma in the medulla oblongata, rather rare vascular lesion in the central nervous system. We describe a such surgical case without additional neurological symptoms and discuss surgical indications in this paper. A 61-year-old woman presented with vertigo and swallowing disturbance. T1-weighted magnetic resonance image (MRI) showed a low intensity mass in the dorsolateral portion of the medulla oblongata, and T2-weighted imaging revealed a hemosiderin rim surrounding the lesion. Angiography showed no abnormalities. Surgery using far lateral approach achieved complete removal of the mass and hematoma. Histological examination of the surgical specimen disclosed cavernous angioma. This case suggests that direct surgery can be recommended for cavernous angioma located in the dorsal or lateral medulla oblongata to remove the hematoma and angioma if bleeding clearly provokes neurological symptoms.

Brain Neoplasms↗
PubMed1997

Dissecting aneurysms of the anterior cerebral artery and accessory middle cerebral artery. Case report.

A 66-year-old woman presented with dissecting aneurysms of the anterior cerebral artery (ACA) and accessory middle cerebral artery (MCA) manifesting as subarachnoid hemorrhage but without radiological evidence of the dissecting aneurysms. Intraoperative observation revealed that the vessel walls were dark purple in color, a typical finding of dissecting aneurysm. The abnormal A1 segment was trapped and the dissecting aneurysm of the accessory MCA was wrapped. In the case of SAH of unknown origin, dissecting aneurysm should always be kept in mind even if the angiogram does not show any abnormal finding. This is the first reported case of dissecting aneurysm of the accessory MCA.

Aged↗
PubMed1997

A convenient method for genotyping of human O6-methylguanine-DNA methyltransferase polymorphism.

O6-methylguanine-DNA methyltransferase (MGMT) is one of the DNA repair enzymes in mammals. We previously screened the variant alleles for the MGMT gene in the general population, and found three variants (V1, V2, V3), two of which caused amino acid substitutions (Leu84Phe for V1, and Trp65Cys for V2). In order to accelerate the ecogenetic and pharmacogenetic studies on MGMT polymorphism, we therefore developed a new PCR-based RFLP method for genotyping. The present method has some advantages over the initial PCR-single strand conformation polymorphism (SSCP) method, particularly regarding its simplicity, rapidity and specificity.

Alleles↗
PubMed1997

Macroscopic and stereomicroscopic diagnosis of superficial flat-type early carcinomas of the gallbladder.

Superficial flat early carcinomas of the gallbladder are rarely detected clinically. We previously reported that these carcinomas display granular, flat, or gastric area-like surface mucosal patterns. However, these patterns are also seen in some non-neoplastic conditions. To more definitively differentiate carcinomas from non-neoplastic lesions, we analyzed the stereomicroscopic structure of macroscopically granular, flat, or gastric area-like mucosal lesions with a methylene-blue contrast technique. Sixteen superficial flat early carcinomas and 65 non-neoplastic flat lesions from surgically resected gallbladders were studied by stereomicroscopy. The fine mucosal structures were classified into three patterns: grooved, pitted, or papillary, each of which was further subdivided into regular and irregular. The frequency of the grooved (52.2%) and papillary (52.2%) patterns was significantly higher in the carcinomas than in the non-neoplastic lesions (24.7% and 1.3%, respectively). The pitted pattern was present in 69.6% of the carcinomas and in 53.2% of the non-neoplastic lesions (the difference was not significant). In the grooved and pitted patterns, the irregular subtypes predominated in the carcinomas (100% and 81.3%, respectively), while the regular subtypes were more frequent in the non-neoplastic lesions (84.2% and 97.6%, respectively). Stereomicroscopic examination of the fine mucosal structures of flat lesions of the gallbladder is very useful in differentiating carcinomas from non-neoplastic lesions.

Adenocarcinoma↗
PubMed1997

Comparative strengths of metal framework structures for removable partial dentures.

STATEMENT OF PROBLEM: The framework of removable partial dentures often breaks where the metal retention for the resin denture base attaches to the clasp and major connector. PURPOSE: To study these failure factors, various types of three-dimensional simulated denture frameworks were designed to measure their ultimate strengths and stiffnesses under static load. This study also sought to determine which could be recommended for long-term clinical service. MATERIAL AND METHODS: Three groups of three-dimensional frameworks (double, T-shaped, and trussed structure) were designed, and two groups of classic framework designs (uniform and nonuniform skeleton) were used with an acrylic resin block as a control (n = 5 per group). Fatigue strength, stiffness and amount of strain, and free-end displacement under dynamic loads were measured for each framework. The fatigue strength was determined with a constant-loading fatigue test by counting the number of loading cycles required to induce catastrophic failure. RESULTS: With 20 kgf of load, four T-shaped samples and three trussed structure samples failed at 30,000 to 60,000 loading cycles. No samples of double structure group failed until 100,000 loading cycles. CONCLUSIONS: Three-dimensional frameworks, especially the double structure, have significant differences in fatigue strength and can provide long-term clinical service.

Chromium Alloys↗
PubMed1997

Increased cartilage and bone formation in spontaneously hypercholesterolemic rats.

Spontaneously hypercholesterolemic (SHC) rats are known to exhibit accelerated bone resorption. We compared endochondral bone formation induced by implantation of demineralized bone matrix (DBM) to 4-week-old SHC rats with that of age-matched Sprague-Dawley (SD) rats. When DBM prepared from adult SD rats was implanted, the cartilageous area enlarged, and C-propeptide of type II procollagen content on day 7 was higher in SHC rats. Alkaline phosphatase activity and calcium content on day 12 and tartrate-resistant acid phosphatase activity on day 19 were higher in SHC rats. These results suggest active chondrogenesis, with a subsequent increase in osteogenesis, and stimulated osteoclastic bone resorption in SHC rats. When DBM from 10-week-old SHC rats was implanted into SD or SHC rats, the levels of bone forming parameters on day 12 were reduced to one-third, suggesting inhibiting factor(s) for bone induction in bone matrix of SHC rats. In contrast, when DBM from 6-month-old SHC rats was implanted, although bone forming parameters in SD rats were comparable to the case of implantation of DBM from SD rats, the accelerated bone formation detected in SHC rats was blocked, indicating resistance to systemic bone inducing factor(s) of SHC rats in aged bone matrix. These results suggest that age-related decrease in responses to some systemic bone inducing factor may lead to the bone loss with advancing age.

Acid Phosphatase↗