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Biomedical subjects

S Kikuchi

Publications and source records attributed to S Kikuchi.

At least 307 records · Page 17Linked to original sources
PubMed1994

[A successful surgical treatment for type IA cor triatriatum with an unroofed coronary sinus].

The combination of type IA cor triatriatum (Lucas-Schmidt's classification) and unroofed coronary sinus is very rare in congenital heart diseases. We have presented the first successful surgical treatment for an infant who had this combination. The patient was 10-month-old infant who admitted with cardiac murmur and short stature. Echocardiography revealed that an abnormal septum in the left atrium and dilated coronary sinus. Under cardiopulmonary bypass she underwent surgical treatment which consisted of a resection of the intra-left-atrial diaphragma, closure of ASD with an equine pericardial patch. During operation, unroofed coronary sinus (partially unroofed terminal portion of the coronary sinus) was revealed. Her postoperative course was uneventful.

Cor Triatriatum↗
PubMed1993

Glutamate neurotoxicity in mesencephalic dopaminergic neurons in culture.

The neurotoxic effect of glutamate in cultured mouse mesencephalic dopaminergic neurons was investigated. Neuron-rich cell cultures were prepared from 13-14-day-old fetal mouse ventral mesencephalic tissue. Cultures were exposed to glutamate for 10 min and evaluated for glutamate neurotoxicity (GNT) 18-24 hr later by tyrosine hydroxylase (TH) immunostaining, microtubule associated protein-2 (MAP2) immunostaining, and radiolabeled dopamine uptake assay. In glutamate-exposed cultures, the number of TH-positive neurons and the level of dopamine uptake were reduced to 40% (35-45%) and 50% (47-52%), respectively, of control cultures. The number of MAP2-positive neurons was also reduced to 47%, indicating that the GNT was not restricted or selective to dopaminergic neurons. It is concluded that GNT was mediated by the N-methyl-D-aspartic acid (NMDA) receptor from the following observations: 1) GNT was completely blocked by MK-801, an NMDA receptor antagonist; 2) NMDA itself was as toxic as glutamate; 3) 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), an antagonist of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainate (AMPA/KA) receptor, did not block GNT; 4) kainate did not show neurotoxicity at a low concentration; and 5) two modulators of the NMDA receptor, 7-chlorokynurenic acid and magnesium, were effective in blocking GNT. Protective effects of phorbol myristate acetate, a tumor promoter, and gangliosides (GM1 and GT1b) on GNT were also demonstrated. Possible interactions between GNT and several protein kinase cascades were also investigated. Forskolin, an activator of adenyl cyclase and protein kinase A, showed some protective effect on GNT. But okadaic acid, an inhibitor of phosphatases, and genistein, a tyrosine kinase inhibitor, did not show any protective effect. These results suggest that 1) glutamate is capable of causing neuronal death in the substantia nigra; 2) GNT on dopaminergic neurons is mainly mediated by the NMDA receptor under the conditions of our study; 3) protein kinase C translocation is a key mechanism of GNT; and 4) there is an interplay of a signal transduction system in the pathomechanism of GNT.

Amino Acids↗
PubMed1993

The natural history of radiographic instability of the lumbar spine.

The natural history of radiographic instability of the lumbar spine was determined by reexamination of 50 patients who had been diagnosed with this condition at least 10 years previously and correlation of these findings with changes in the clinical condition. The initial diagnosis and follow-up examination was performed by dynamic radiography, and the following observations were made: 1) radiographic instability resolved spontaneously in 20% of cases; 2) radiographic instability due to isolated posterior opening (asymmetric anterior collapse of the intervertebral disc in flexion) usually was self-limited; and 3) combined posterior opening and forward translation in flexion was associated with chronic instability and debilitating symptoms. The functional prognosis, whether or not symptoms are improved, in patients with radiographic lumbar instability depends primarily on developmental narrowing of the spinal canal, rather than on the existence or type of radiographic instability.

Activities of Daily Living↗
PubMed1993

Intramedullary spinal cord sarcoidosis. Report of two cases.

Two cases of intramedullary spinal cord sarcoidosis are reported. These lesions could not be differentiated from neoplastic spinal cord tumors by clinical findings or imaging studies. In magnetic resonance imaging, the lesions were enhanced around the gray matter with gadlinium diethylene triamine pentaacetic acid (Gd-DTPA). The true diagnosis was established only by histologic examination of the surgical specimen. The possibility of intramedullary sarcoidosis presenting as a tumor should be included in the differential diagnosis of mass lesions of the spinal cord.

Aged↗
PubMed1993

Midkine, a novel neurotrophic factor, promotes survival of mesencephalic neurons in culture.

Midkine (MK), a retinoic acid responsive gene product, is a novel neurotrophic factor with a molecular weight of 14,000. MK at the optimal concentration of 10 ng/ml promoted the survival of mouse mesencephalic neurons in culture as demonstrated by the increased number of microtubule-associated protein-2 (MAP2) immunostaining-positive and tyrosine hydroxylase immunostaining-positive neurons and an elevated uptake of radiolabeled dopamine. These results suggest that MK has ubiquitous neurotrophic activity towards mesencephalic neurons which contain a large number of dopaminergic neurons.

Animals↗
PubMed1993

Retinoic acid responsive gene product, midkine, has neurotrophic functions for mouse spinal cord and dorsal root ganglion neurons in culture.

Midkine (MK) is the product of a retinoic acid responsive gene and is a member of a new family of heparin-binding growth factors. Neurotrophic effects of MK were examined using cultured spinal cord and dorsal root ganglion (DRG) neurons derived from fetal mouse. MK, which was added to the culture medium at concentrations of 1-100 ng/ml, promoted survival of both types of neurons approximately 5-fold after 7 days in culture. For spinal cord neurons, the increased survival was reflected in an increase of choline acetyltransferase activity. MK also promoted neurite extension in spinal cord (2-fold) and DRG (1.7-fold) neurons. The survival-promoting activity of MK to these neurons was comparable to that of basic fibroblast growth factor (bFGF) and leukemia inhibitory factor (LIF). In spite of its significant effects on fetal neurons, MK was ineffective in sustaining survival of DRG neurons derived from postnatal mice. From these results, we conclude that MK is a neurotrophic factor to embryonic spinal cord and DRG neurons, and we propose that MK plays a significant role in embryogenesis of the nervous system.

Animals↗
PubMed1993

Kinetic study of free-radical-scavenging action of biological hydroquinones (reduced forms of ubiquinone, vitamin K and tocopherol quinone) in solution.

Kinetic study of free-radical-scavenging (FRS) action of eight kinds of biologically important hydroquinones (HQ's) (ubiquinol-10 (UQ10H2 1), ubiquinol-0 (UQ0H2 2), vitamin K1 HQ (VK1H2 3), vitamin K3 HQ (VK3H2 4), alpha-, beta-, gamma-tocopherol HQ's (alpha-, beta-, gamma-TQH2 5, 6, 7), and 2,3,5-trimethyl-1,4-HQ (TMQH2 8)) has been performed. The second-order rate constants, k3, for the reaction of HQ's 1-8 with substituted phenoxyl radical (PhO.) in ethanol, diethyl ether, benzene, and n-hexane have been measured with a stopped-flow spectrophotometer, as a model reaction of HQ's with unstable free radicals (LOO., LO., and HO.) in biological systems. The rate constant of UQ10H2 1 is similar to that of alpha-tocopherol in ethanol. The HQ's 3-8 showed higher reactivity than alpha-tocopherol in ethanol. Especially, the rate constants of VK1H2 3 and VK3H2 4 were found to be 31- and 21-fold larger than that of alpha-tocopherol, respectively, which has the highest reactivity among natural tocopherols. The rate constant of these HQ's increased by decreasing the polarity of solvents. The approximate order of magnitude of k3 value was (i) VK1H2 and VK3H2 > (ii) alpha-, beta-, and gamma-TQH2's and TMQH2 > (iii) alpha-tocopherol > (iv) UQ10H2 and UQ0H2 in solution. The result suggests that these biological HQ's also scavenge the active oxygen free radicals and prevent lipid peroxidation in various tissues and membranes. On the other hand, the reaction between substituted phenoxyl and biological quinones has not been observed.

Free Radical Scavengers↗
PubMed1993

[Reappraisal of the clinical usefulness of transabdominal ultrasonography for advanced colon cancer--a study of tumor detection].

We evaluated the detectability of colon cancer by using transabdominal ultrasonography (US). Fifty-three cases of proven advanced colon cancer were examined in this study. Screening by US was carried out in 27 of 53 cases and US was performed in all cases after the definite diagnosis. Lesions of the colon were examined by using a 3.5 MHz convex and 5 MHz or 7.5 MHz linear probe (Yokogawa RT-2800, RT-4600). Localized hypertrophy of the irregular wall of more than 10 mm or massive tumor without the normal layered structure was defined as colon cancer on US. The rate of detection by screening test was 52%. The detection rate by US after definite diagnosis was 75%. A high detection rate was obtained in cases with a tumor diameter of more than 4 cm. Eight of 13 cases which were not detected by the screening test were visualized by US after definite diagnosis. US examination is useful for the detection of certain extended lesions of colon cancer. With technical improvements of the examination method, it is considered that cancer in the gastrointestinal tract may be discovered early on screening tests using US.

Adult↗
PubMed1993

An electrocochleographic study of acute low-tone sensorineural hearing loss.

Twenty-four patients with acute low-tone sensorineural hearing loss (ALHL) were examined using electrocochleography. The negative summating potential (SP) amplitude and the summating potential/action potential (AP) ratio were significantly greater in the ALHL patients than in normals. The SP/AP ratio was smaller in the ALHL patients than in patients with known Meniere's disease and moderate hearing loss, although the SP amplitude was somewhat greater in the former. An abnormal increase in the SP amplitude following click stimuli was found in 54% of the ALHL patients, while the SP/AP ratio was increased abnormally in 63% of these patients. These findings suggest that the pathophysiology of ALHL may be similar to that for endolymphatic hydrops.

Acoustic Stimulation↗
PubMed1993

Is an isthmus block a prerequisite for the development of an attic retraction cholesteatoma?

Computed tomography (CT) was used to investigate whether an isthmus block was present in 57 cases with attic retraction cholesteatomas. A ventilation route between the mesotympanum and attic was considered to exist in 30% of the cases and occurred predominantly in those ears with a cholesteatoma that did not extend into the antrum. Four cases were also found to have this ventilation route in CT scans taken before and after the development of cholesteatoma. These findings suggest that an isthmus block is not a prerequisite for the development of an attic retraction cholesteatoma.

Cholesteatoma↗
PubMed1993

Production and characterization of antibodies to the beta-(1-->6)-galactotetraosyl group and their interaction with arabinogalactan-proteins.

Rabbit antisera were raised against beta-(1-->6)-galactotetraose coupled to bovine serum albumin (Gal4-BSA). The antisera reacted with arabinogalactan-proteins (AGPs) isolated from seeds, roots, or leaves of radish (Raphanus sativus L.) as revealed by immunodiffusion analysis. Extensive removal of alpha-L-arabinofuranosyl residues from these AGPs enhanced the formation of precipitin with the antisera. The antisera did not react with such other polysaccharides as soybean arabinan-4-galactan, beta-(1-->4)-galactan, and beta-(1-->3)-galactan, indicating their high specificity toward the consecutive beta-(1-->6)-galactosyl side chains of AGPs. The antibodies were purified by affinity chromatography on a column of immunobilized beta-(1-->6)-galactotetraose as ligand. The specificity of the antibodies toward consecutive (1-->6)-linked beta-galactosyl residues was confirmed by enzyme-linked immunosorbent assay for hapten inhibition against Gal4-BSA as antigen, which revealed that beta-(1-->6)-galactotriose and -tetraose were potent inhibitors, while beta-(1-->3)- or beta-(1-->4)-galactobioses and -trioses were essentially unreactive. Electron-microscopic observation of immunogold-stained tissues demonstrated that AGPs were localized in the middle lamella as well as at the plasma membrane of primary roots of radish. Agglutination of protoplasts prepared from cotyledons occurred with the antibodies, supporting the evidence for localization of AGPs in the plasma membrane. The antibody-mediated agglutination was inhibited by addition of AGPs or beta-(1-->6)-galactotetraose.

Agglutination↗
PubMed1993

High degree of genetic polymorphism in apolipoprotein(a) associated with plasma lipoprotein(a) levels in Japanese and Chinese populations.

We have developed a sensitive, high-resolutin method for the analysis of the apolipoprotein(a) [apo(a)] isoforms using sodium dodecyl sulfate (SDS)-agarose/gradient polyacrylamide gel electrophoresis. In an analysis of the genetic polymorphism of apo(a) isoforms and their relationship with plasma lipoprotein(a) [Lp(a)] levels in Japanese and Chinese, this method identified 25 different apo(a) isoforms and detected one or two apo(a) isoforms in more than 99.5% of the individuals tested. The apparent molecular weights of the apo(a) isoforms ranged from 370 kDa to 950 kDa, and 22 of the 25 different apo(a) isoforms had a higher molecular weight than of apo B-100. Studies on Japanese families confirmed the autosomal codominant segregation of apo(a) isoforms and the existence of a null allele at the apo(a) locus. The observed frequency distribution of apo(a) isoform phenotypes fit the expectations of the Hardy-Weinberg equilibrium in both the Japanese and Chinese populations. Our data indicate the existence of at least 26 alleles, including a null allele, at the apo(a) locus. The frequency distribution patterns of the apo(a) isoform alleles in Japanese and Chinese were similar to each other and also similar to that of apo(a) gene sizes reported in Caucasian American individuals. The average heterozygosity at the apo(a) locus was 92% in Japanese and 93% in Chinese. A highly significant inverse correlation was observed between plasma Lp(a) levels and the size of apo(a) isoforms in both the Japanese (r = 0.677, P = 0.0001) and the Chinese (r = -0.703, P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1993

Frequent occurrence of familial aggregations of high lipoprotein(a) levels associated with small apolipoprotein(a) isoforms.

School-age children with high lipoprotein(a) [Lp(a)] levels were screened and family studies were conducted to examine the relationship between high Lp(a) levels and apolipoprotein(a) [apo(a)] isoforms in families. All the probands from 17 families had one of the A2 to A12 apo(a) isoforms, which are the smaller apo(a) isoforms of the 25 different isoforms thus far detected. The ratio of subjects with high plasma Lp(a) levels was 0.47 among the first-degree relatives. All 15 relatives with high plasma Lp(a) levels shared one of the small apo(a) isoforms with the proband in each family, while 16 of 17 relatives with normal Lp(a) levels did not. These data indicate the frequent occurrence of familial aggregations of high Lp(a) levels associated with one of the small apo(a) isoforms.

Alleles↗
PubMed1993

Nasal neurinoma: case report and review of literature.

We report a rare case of nasal neurinoma. The patient was a 21-year-old man, who complained of nasal obstruction. The tumor was successfully excised, and was found to be a benign Schwannoma (neurinoma). The patient had an uneventful course with no signs of recurrence. Reports in the world literatures of neurinomas in the nasal cavity and the paranasal sinuses are reviewed.

Adult↗
PubMed1993

An analysis of bone destruction in cholesteatomas by high resolution computed tomography.

Using sectional images of high resolution computed tomography, a quantitative analysis of bone destruction has been undertaken in 73 adult cases with cholesteatoma, 52 having a pars flaccida cholesteatoma (PFC) and 21, a pars tensa cholesteatoma (PTC). These cholesteatomas were further classified into two subtypes: an extended type (cholesteatomas that had extended into the antrum) and a non-extended type (cholesteatomas without an antral extension). Similarly analyzed were 60 cases manifesting chronic otitis media with a central perforation (COM) comparatively. This analysis was performed by means of two-dimensional images and by linear measurement, taken at specific locations in each middle ear cavity. The results revealed that the width of the attic was significantly greater in both the PFC and PTC cases than in the COM cases. Further, a significantly greater distance between the malleus and the lateral wall of the attic was seen in the PFC cases than in the COM cases. In contrast, the distance between the malleus and the medial wall of the attic was significantly greater in the PTC cases than in the COM cases. The extended-type cases had significantly greater distances than did the COM cases with regard to the width of the aditus ad antrum, and the width and anterior-posterior diameter of the antrum. These distances, however, did not significantly differ between the non-extended-type cases and the COM cases. It thus appears that these distances, caused by bone destruction, appear to parallel the extension of the cholesteatoma into the antrum.

Cholesteatoma↗
PubMed1993

Melano-macrophage centre-like structure in the heart of the medaka, Oryzias latipes.

Endocardial lining cells in the heart of certain teleosts are phagocytic against foreign materials. In the medaka Oryzias latipes, in addition to the endocardial lining cells, cells in the subendocardial spaces are also phagocytic. Most subendocardial cells contain yellowish-brown pigments and are often aggregated to form nodules resembling splenic and kidney melano-macrophage centres. Subendocardial cells are positive to PAS and Schmorl's reaction. Macrophages containing large heterogeneous inclusions together with lymphocytes, were observed with the TEM. The definitive characteristics of reticular cells, including the cell sheaths, were not observed. Because of these two characteristics they were regarded as more primitive aggregates of macrophages than the ordinary melano-macrophage centres. The possible analogy between these structures and MMCs is discussed.

Animals↗
PubMed1993

Apolipoprotein(a) phenotypes and serum lipoprotein(a) levels in maintenance hemodialysis patients with/without diabetes mellitus.

We studied the quantitative and qualitative characteristics of lipoprotein(a) [Lp(a)] as a function of apolipoprotein(a) [apo(a)] phenotypes in 152 patients (123 males, 29 females) undergoing maintenance hemodialysis (HD) with or without diabetes mellitus (DM), in 101 patients with diabetes mellitus without hemodialysis (58 males, 43 females), and in 421 normal controls (333 males, 88 females). Serum Lp(a) levels were significantly (P < 0.01) higher in patients than in controls (26.2 +/- 18.3 mg/dl in HD with DM, 26.4 +/- 22.0 mg/dl in HD without DM, 27.1 +/- 27.3 mg/dl in DM without HD, and 14.9 +/- 13.7 mg/dl in controls, respectively). Apo(a) phenotyping was performed by a sensitive, high resolution technique using SDS-agarose/gradient (3 to 6%) PAGE. In normal controls, the molecular weights of apo(a) isoforms were inversely correlated with plasma Lp(a) levels, and the same tendency was found in patients who were undergoing hemodialysis and/or who had diabetes mellitus. We assumed the differences in apo(a) phenotypes detectable with our method reflected consecutive differences in molecular weights of apo(a). The results of an analysis of covariance and a least square means comparison indicated that the regression lines between serum Lp(a) levels [log Lp(a)] and apo(a) phenotypes in patient groups were significantly (P < 0.01) elevated for every apo(a) phenotype, as compared to the regression line of the control group. Even after the low molecular weight apo(a) phenotypes (A1-A8) were omitted, the same tendency was observed. However, no differences were observed between the patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗