Biomedical subjects

N Maeda

Publications and source records attributed to N Maeda.

At least 721 records · Page 40Linked to original sources

PubMedDate not supplied

Transient focal cortical hypometabolism in idiopathic West syndrome.

Positron emission tomography (PET) using 18F-labeled 2-deoxy-D-glucose was performed serially in 5 infants with idiopathic West syndrome. While tonic spasms persisted, 2 infants had hypometabolism in the bilateral temporo-parieto-occipital regions, which disappeared after cessation of spasms. In 2 other infants, PET revealed focal hypometabolism in the temporal region a few months after the disappearance of tonic spasms, but subsequent PET studies were normal. PET can detect transient metabolic abnormalities of the cerebral cortex which may be associated with the pathophysiology of West syndrome.

Blood Glucose↗

PubMedDate not supplied

Electrostatic repulsion among erythrocytes in tube flow, demonstrated by the thickness of marginal cell-free layer.

Electrostatic repulsion among erythrocytes in flow was evaluated through measurement of the thickness of the marginal cell-free layer in narrow glass tubes of 20-50 microns in inner diameter. To reduce the electrostatic repulsive force, due mainly to sialic acid of the membrane glycoproteins, human erythrocytes were treated with neuraminidase. The surface negative charge of the erythrocytes, as determined from the electrophoretic mobility using free-flow electrophoresis, was found to be proportional to the sialic acid content. When erythrocytes with decreased sialic acid content flowed through narrow tubes, the thickness of cell-free layer determined using an image processor increased even in the absence of erythrocyte aggregation in the suspension. The effect was more pronounced at acidic pH. The addition of Dextran T-70 (70,400 Mol. Wt.) further increased the cell-free layer thickness due to erythrocyte aggregation. Thus, reducing the negative charge density on the erythrocyte surface by itself accelerates the axial accumulation of erythrocytes in flow due to the decreased electrostatic repulsive force between the cells, even in the absence of erythrocyte aggregation.

Blood Flow Velocity↗

PubMedDate not supplied

Videokeratography for quantitative surface analysis of used soft contact lenses.

The greater utilization of soft contact lenses calls for the development of new and objective methods of evaluating the optical performance of the different lens types, in situ. We used videokeratography to examine the surface topography of soft contact lenses that had been worn for more than 1 year on 27 eyes of 23 patients, and compared the resulting color-coded maps and topographic indices as well as contact lens-corrected visual acuities, with those obtained with new replacement lenses on the same eyes. Visual inspection of the color-coded maps revealed differences in the surface characteristics of the used and new lenses. Comparison of quantitative indices including the SAI (Surface Asymmetry Index), IAI (Irregular Astigmatism Index), SRI (Surface Regularity Index), and SDP (Standard Deviation of Powers) showed that asymmetry, surface irregularity, potential visual acuity (derived from the SRI), and corneal power distribution were significantly poorer with the used lenses than with the new (P = 0.0001). The videokeratoscope is useful for evaluating the soft contact lens surface in situ, as an indicator of optical quality; it also permits the objective evaluation of lens cleaning techniques.

Adolescent↗

PubMedDate not supplied

Use of dynamic and colored stereogram to measure stereopsis in strabismic patients.

The effectiveness of movement or color has not been well studied in assessing stereopsis in patients with strabismus. We developed a new stereotest equipped with both a monochromatic dynamic random dot stereogram (DRDS) and a static-colored stereogram (SCS) and examined the stereopsis of patients with strabismus. Three-dimensional (3D) images were displayed on a liquid crystal display equipped with a parallax barrier system, allowing 3D images to be seen independently by each eye without glasses. A DRDS with maximum disparity of 3200 seconds of arc was displayed having front-rear movement. An SCS displaying cartoon characters with disparities of 400 seconds of arc was also tested and compared with the Titmus stereotest. A total of 52 strabismic patients were tested. The DRDS showed a significantly higher (P = 0.02) detection rate of stereopsis (39/52, 75%) as compared with the Titmus fly test (28/52, 54%). The SCS did not show any difference in the stereopsis detection rate (24/521, 46%) when compared with the Titmus animal test (20/52, 38%). Thus, the DRDS was useful in detecting stereopsis in patients without stereopsis on the conventional Titmus fly test, while the SCS did not show any difference when compared with the Titmus animal test. The DRDS may examine a different aspect of stereopsis from the static stereopsis measured by the Titmus stereotest or SCS.

Adolescent↗

PubMedDate not supplied

Corneal changes in spondyloepiphyseal dysplasia tarda.

BACKGROUND: A new type of corneal opacity with prominent corneal nerve fibers as an ocular complication of spondyloepiphyseal dysplasia tarda (SEDT). CASE: A 58-year-old woman, diagnosed with SEDT at 5 years of age, underwent a complete ophthalmological examination. OBSERVATIONS: The patient had no complaints and no history of eye disease. No relatives were reported to have suffered from SEDT. Slit-lamp examination disclosed a diffuse opacity in the central cornea in both eyes, which was localized in the middle to deep stroma. Dot opacities in the central and paracentral cornea were located in the middle of the stroma in both eyes. Optically clear regions were observed in the peripheral cornea of both eyes. More interestingly, corneal nerve fibers were visible passing from the limbus to the central cornea in both eyes. RESULTS: The etiology of the corneal opacities of this patient with SEDT is unknown. However, collagen and proteoglycan abnormalities in the skin of patients with SEDT have been reported. Therefore, such abnormalities may also be present in the cornea and these alterations may lead to corneal complications.

Blinking↗

PubMedDate not supplied

Detection and classification of mild irregular astigmatism in patients with good visual acuity.

Videokeratography has been available for a decade, and this test is essential for determining the presence and type of irregular corneal astigmatism. Three eyes diagnosed with myopic astigmatism and considered good candidates for refractive surgery with conventional examination were studied. Color-coded maps with videokeratography showed regular astigmatism in one eye and the existence of irregular astigmatism in two eyes. Videokeratography showed that one of these eyes had a keratoconus suspect pattern and the second showed a pattern consistent with pellucid marginal degeneration. Videokeratography can detect and classify irregular astigmatism in cases where routine examination shows no abnormal findings.

Adolescent↗

PubMedDate not supplied

Cis-acting human ApoE tissue expression element is associated with human pattern of intraneuronal ApoE in transgenic mice.

Apolipoprotein E polymorphic variants (ApoE-epsilon2, epsilon3, and epsilon4) are associated with the age of onset distribution and risk of Alzheimer disease. The question of whether ApoE is expressed at a comparatively low level in human neurons compared to astrocytes, or whether ApoE enters neuronal cytoplasm via altered endosomal metabolism is important to understanding potential pathogenic roles for ApoE as a susceptibility gene in Alzheimer disease. ApoE deficient ("knock-out") mice received large human genomic DNA fragment transgenes for each of the three common apoE alleles. All transgenic mice demonstrated glial/astrocytic (normal rodent pattern), as well as cortical intraneuronal ApoE immunoreactivity with all three human isoforms and at multiple ApoE human allele doses (Xu et al. (32)). To test whether ApoE intraneuronal immunoreactivity was due to ApoE gene sequences between mouse and human, we examined another set of mice constructed using targeted replacement so that the human ApoE gene was placed under mouse gene promoters. Current analyses show that targeted replacement recombinant mice show normal rodent glial expression pattern, but no ApoE neuronal immunoreactivity through six months of age compared to large human genomic DNA fragment transgenic mice, which show neuronal content of ApoE throughout adult life. We conclude that cis-acting DNA sequences, rather than the specific sequence of the ApoE gene, may be responsible for low levels of transcription activity in cortical neurons.

Alleles↗

PubMedDate not supplied

Duplication within the haptoglobin Hp2 gene.

DNA sequencing shows that the intragenic duplication within the human haptoglobin Hp2 allele was formed by a non-homologous, probably random, crossing-over within different introns of two Hp1 genes, probably in an Hp1F / Hp1S heterozygote.

Alleles↗

PubMedDate not supplied

Inequality in mutation rates of the two strands of DNA.

As the mechanisms for replicating the two strands of duplex DNA differ it is, in principle, possible for the mutation rates to differ depending on which strand is being copied. In the absence of selection this would lead to a difference in the measured rate of a particular base substitution, such as T to C, depending on which DNA strand was analysed to determine the rate. Thus a change such as T to C on one DNA strand results from either a direct T-to-C mutation on that strand or an A-to-G mutation on the complementary strand; for the other strand the situation is reversed, and it can be seen that different processes are responsible for the two cases, allowing for asymmetry in substitution rate. We have tested whether such asymmetry indeed occurs by studying equivalent sequences from the beta-globin complexes of six species of primate. Our results reveal an asymmetry in substitution rates consistent with predictions based on strand-inequalities in mutation rates. Our sequence comparisons also allow us to make predictions about the positions of replication origins and the replication error rates of one strand relative to the other.

Animals↗

PubMedDate not supplied

Targetted correction of a mutant HPRT gene in mouse embryonic stem cells.

Two recent developments suggest a route to predetermined alterations in mammalian germlines. These are, first, the characterization of mouse embryonic stem (ES) cells that can still enter the germline after genetic manipulation in culture and second, the demonstration that homologous recombination between a native target chromosomal gene and exogenous DAN can be used in culture to modify specifically the target locus. We here use gene targetting functionally to correct the mutant hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene in the ES cell line which has previously been isolated and used to produce an HPRT-deficient mouse. This modification of a chosen gene in pluripotent ES cells demonstrates the feasibility of this route to manipulating mammalian genomes in predetermined ways.

Animals↗

PubMedDate not supplied

Effects of soy protein diet on the expression of adipose genes and plasma adiponectin.

Many studies have reported the cholesterol-lowering, anti-lipogenic, anti-obesity and anti-hypertensive effects of soy protein. Adipose tissue-specific plasma protein, adiponectin, has anti-atherogenic and anti-insulin-resistance properties. Here, we investigated the effects of soy protein diet on body fat composition, plasma glucose, lipid and adiponectin levels and expression of genes involved in glucose and fatty acid metabolism in obese KK-A y mice. Body weights and adipose tissue weights of mesenteric, epididymal, and brown fat were lower in mice on calorie-restricted diet containing soy protein isolate. Plasma cholesterol, triglyceride, free fatty acid, and glucose levels were also decreased by this diet. Body fat content and plasma glucose levels in mice on a soy protein isolate diet were still lower than those treated with an isocaloric casein-protein-diet. Among the genes related to glucose and fatty acid metabolism, adiponectin mRNA levels in adipose tissue and adiponectin plasma concentrations were elevated in mice on a calorie-restricted diet, although there were no significant differences between soy protein and casein protein groups. Our results indicate that that soy protein diet decreased body fat content and plasma glucose levels more effectively than isocaloric casein-protein diet in obese mice.

Adiponectin↗

PubMedDate not supplied

Mass screening for hepatocellular carcinoma: experience in Hokkaido, Japan.

Mass screening for liver cancer based mainly on abdominal ultrasound was begun in major cities of Hokkaido, Japan, in November 1981, to enable early detection and treatment of hepatocellular carcinoma (HCC). Serum alpha-fetoprotein levels were also measured to minimize false negative studies. Examinees included those who sought liver disease screening as well as high risk individuals: hepatitis B surface antigen carriers and those with a past or current liver disease, history of blood transfusion, family history of liver cancer, and more recently those with positive anti-hepatitis C antibodies. The examination was carried out on each Saturday and Sunday as one round, and by February 1992 48 rounds had been performed. A total of 8090 individuals were investigated, and HCC was detected in 91 with a detection rate of 1.12%. This rate was 1.6% among 5684 individuals who were selected for high risk. Cumulative rates of survival among these patients were 79.0% at 1 year, 43.8% at 3 years, 19.3% at 5 years and 15.4% at 7 years. These survival rates were comparable with those for the patients with HCC diagnosed during follow-up of chronic liver disease and treated at our hospital. The cost for detecting one HCC patient in this programme was 2,660,000 yen (approximately US$25,000), which was less than those for some other types of cancer in a similar setting. Considering the high detection rate in this programme, we feel that similar programmes should be encouraged and supported.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Differential expression of the alpha1 type VIII collagen gene by smooth muscle cells from atherosclerotic plaques of apolipoprotein-E-deficient mice.

We have investigated the morphology, growth and gene expression of smooth muscle cell (SMC) cultures derived from advanced atherosclerotic plaques and from non-plaque-containing aorta of individual apolipoprotein-E-deficient mice. The initial outgrowth of cells was faster from plaques (P) than from non-plaque segments (NP), but the cells in P cultures divided more slowly than NP cells in subcultures. By the 6th passage, the general growth pattern, morphology, ploidy and response to mitogenic factors of the cells were no longer consistently different in P and NP cultures. However, by the use of differential display, several transcripts were identified that were differentially expressed in three independent pairs of P and NP cultures. One of the transcripts, from a type VIII collagen gene, was elevated in all the P cultures compared to their NP counterparts even at the 40th passage. The alpha1 type VIII collagen transcripts were also readily detectable by RT-PCR in freshly dissected plaques, but not in the normal parts of aortas from the apolipoprotein-E-deficient mice. In situ hybridization showed that the transcripts were limited to the fibrous cap of plaques. Thus, SMCs from atherosclerotic plaques produce type VIII collagen and this differential expression continues when the cells are maintained in tissue culture.

Animals↗

PubMedDate not supplied

Flow behavior of erythrocytes in microvessels and glass capillaries: effects of erythrocyte deformation and erythrocyte aggregation.

Flow behavior of erythrocytes in microvessels and glass capillaries with an inner diameter of 10-50 microns was compared in relation to erythrocyte deformation and erythrocyte aggregation. This study was focused on the formation of a marginal cell-free layer, and the thickness was determined using an image processor. Human erythrocytes were perfused through a part of microvascular networks isolated from rabbit mesentery and through glass capillaries. Erythrocyte deformability was modified by treating erythrocytes with diamide, diazene-dicarboxylic acid bis[N,N-dimethylamide], and erythrocyte aggregation was accelerated by adding dextran (with a molecular weight of 70,400) to the perfusion medium. The thickness of the cell-free layer increased with an increase of the inner diameter of flow channel, with lowering the hematocrit, and with increasing the flow velocity of erythrocytes, in both microvessels and glass capillaries. Furthermore, the thickness of cell-free layer decreased with decreasing erythrocyte deformability, while it increased with accelerating erythrocyte aggregation. However, the alteration of the cell-free layer in response to the changes of these hemorheological conditions was more sensitive in microvessels than in glass capillaries. The present study concludes that flow behavior of erythrocytes in microvessels is qualitatively similar to, but quantitatively different from those in glass capillaries, as far as evaluated by the change of the thickness of the marginal cell-free layer.

Animals↗

PubMedDate not supplied

A spontaneous testicular teratoma in an ICR mouse.

A spontaneous teratoma was detected in the left testis of a 7-wk-old male ICR (Crj:CD-1) mouse. The tumor was composed of a variety of well-differentiated tissue elements from all 3 germ layers including neuronal tissue and stratified epithelium as ectoderm-derived tissues, bone, cartilage, striated muscle, and adipose tissue as mesodermal tissues, and respiratory columnar epithelium as endoderm-originated tissue. No tumor metastasis was detected. It may be of congenital origin as in strain 129 mice. To the best of our knowledge, this is the first report concerning spontaneous testicular teratoma in a strain ICR mouse.

Animals↗

PubMedDate not supplied

Immunoglobulin binding factor in human seminal plasma: immunological function.

Human seminal plasma contains a protein with an estimated molecular weight of 16 kd that binds serum immunoglobulin gamma (IgG) and is named IgG binding factor (IgBF). Purified IgBF specifically suppressed pokeweed mitogen-induced lymphocyte blastogenesis, having little or no effect on lymphocyte blastogenesis stimulated with phytohemagglutinin or Concanavalin A; antibody-dependent cell-mediated cytotoxicity; natural killer cell activity; or complement-dependent cytotoxicity of antibodies against sperm. It would appear that IgBF may suppress activation of B cells in the male and female genital tract.

Antibody-Dependent Cell Cytotoxicity↗

PubMedDate not supplied

Colocalization of immunoglobulin binding factor and prostate specific antigen in human prostate gland.

Immunoglobulin binding factor (IgBF) produced in the prostate is a useful marker for the diagnosis of prostatic tumor. IgBF was localized in the majority of epithelial cells of benign prostatic hypertrophy by an immunohistochemical technique. Prostate specific antigen (PSA), a known marker for prostatic cancer, was localized to all epithelial cells. Double immunolabeling of IgBF and PSA using fluorescent methods revealed that all epithelial cells producing IgBF were also immunopositive for PSA and some cells were positive only for PSA. The present findings suggest that the prostatic glands consist of two types of epithelial cells, one producing both IgBF and PSA and the other producing PSA alone.

Humans↗

PubMedDate not supplied

Presence of immunoglobulin binding factor on human sperm surface as sperm coating antigen.

The presence of IgBF as a sperm-coating antigen was demonstrated by showing that anti-IgBF antibodies agglutinate and immobilize human sperm and by localizing IgBF on sperm surface by immunofluorescence staining. Several components interacting with sperm immobilizing antibodies, known to be involved in infertility, are sperm-coating antigens. Anti-IgBF antibody in vitro did not block the ability of human sperm to penetrate human zona pellucida and zona-free hamster egg. Anti-IgBF activity of sera obtained from infertile women did not correlate with the titers of anti-sperm antibodies measured by the sperm immobilization test. IgBF is a sperm-coating antigen and may play a role in suppressing antibody production against alloantigenic sperm in the female reproductive tract.

Animals↗