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Biomedical subjects

N Maeda

Publications and source records attributed to N Maeda.

At least 523 records · Page 29Linked to original sources
PubMed1988

Effect of pH on the velocity of erythrocyte aggregation.

The effect of pH on the velocity of aggregation of human erythrocytes was quantitatively examined with a rheoscope combined with a video-camera, an image analyzer and a computer, in relation to the morphological changes of erythrocytes and their aggregates. (i) With increasing pH of the medium, the velocity of erythrocyte aggregation increased. (ii) The rouleaux formed at high pH were longer in shape and more stable against the increase of shear rate than those formed at low pH. (iii) With increasing pH, the diameter of erythrocyte increased, the (maximum) thickness decreased, and the cell volume decreased. The pH dependency of erythrocyte aggregation may be mainly due to the morphological change of erythrocytes, and partly due to the changes of erythrocyte deformability and of interaction with macromolecules.

Erythrocyte Aggregation↗
PubMed1988

Effects of fine-grained diet on annulospiral endings of muscle spindles in the masseter muscle in developing and adult mice.

In the masticatory muscles, neuromuscular spindles have a very important role in controlling the jaw movement since they act as stretch receptors in skeletal muscles. The continuous intake of fine-grained diet which is easily chewable leads to degeneration of the sensory endings of Ia fibers in many muscle spindles of the mouse masseter muscle in only 120 d after birth.

Animals↗
PubMed1988

Effects of the infraorbital nerve-transection on the formation of Ia fibers in muscle spindles of the masseter muscle in developing mice.

The effect of the transection of the infraorbital nerve on d 20 after birth on the formation of the annulospiral ending of Ia fibers of muscle spindles in the masseter muscle was investigated in developing mice. On the 20th d after the operation, there were significant differences between control and treated animals in the ratio of muscle spindles with non-coiled endings to all muscle spindles, and the ratios of muscle spindles with non-coiled endings in the masseter muscle on the operated and sham-operated sides were about equal to each other. On the 30th d after the operation, the ratio for the masseter muscle on the operated side was approximately twice that for the one on the sham-operated side. The ratio for the operated side was about equal to that for 15-d-old control mice, and about twice that for 20-d-old control animals. Thus, the present results indicate that disorder of sensory inputs following the transection of the infraorbital nerve leads to degeneration and/or inhibition of the formation of annulospiral endings in muscle spindles of the masseter muscle, and suggest that disorder of the masticatory mechanism may be caused by the degeneration and/or inhibition of the formation of the endings in many muscle spindles of the masseter muscle.

Animals↗
PubMed1988

Cystatin superfamily. Evidence that family II cystatin genes are evolutionarily related to family III cystatin genes.

Human saliva contains at least three molecular species of cystatin S-type cysteine proteinase inhibitor (cystatin S, cystatin SN and cystatin SA), which have similar but distinct amino-acid sequences. The nucleotide sequences of the CST 1 gene for cystatin SN and the CST 2 gene for cystatin SA are highly homologous to each other and to the corresponding regions of the cDNA for cystatin C and the EcoRI-PstI fragment from the cystatin C gene. Three cystatin-like domains in the kininogen gene and the salivary cystatin genes share the same gene organizations. These data demonstrate that family II cystatin genes are evolutionarily related to family III cystatin genes.

Amino Acid Sequence↗
PubMed1988

Postnatal development of the annulospiral endings of Ia fibers in muscle spindles of the mouse temporal muscle.

The formation of the annulospiral endings of Ia fibers in muscle spindles was investigated in the temporal muscle of developing mice. From 15 to 20 d after birth, there were only a few spindles with "++" sensory endings. With growth of mice, the primary endings of the Ia fiber began to develop its spiral endings. And by the 30th postnatal day (that is, after weaning), almost all of the Ia fibers had completely coiled endings though the formation was still continuing in some spindles at this time. Formation of the annulospiral endings of the Ia fibers of muscle spindles in the temporal muscle was completed earlier than that of fibers in the spindles in the masseter muscle.

Animals↗
PubMed1988

Primary structure comparison of the proposed low density lipoprotein (LDL) receptor binding domain of human and pig apolipoprotein B: implications for LDL-receptor interactions.

Apolipoprotein B (apoB) is the predominant protein in low density lipoprotein (LDL) and is responsible for LDL binding to the LDL receptor. Although the primary amino acid sequence of human apoB has been determined, little is known about the structural domains involved in mediating apoB binding to the LDL receptor. Amino acid sequence comparisons across species lines provide a means of defining structures that are essential for function. We have sequenced a l.l kb fragment of pig apoB genomic DNA, corresponding to a 363 amino acid segment proposed to mediate human apoB binding to the LDL receptor. In human apoB this domain contains two regions enriched in positively charged amino acids flanking two disulfide-linked cysteine residues. The pig amino acid sequence shared 72% identity with the human sequence. However, there were differences that have significant structural and functional implications. Human apoB arginine-3,359 corresponds to a critical arginine (position 142) residue in the apoE LDL receptor binding domain. In the pig, this arginine residue was not conserved. Also, the two disulfide-linked cysteine residues found near the proposed apoB binding domain were not conserved in the pig. Despite these differences, pig LDL had a higher affinity than human LDL for both the pig and human LDL receptor. Thus, these features are not required for high affinity binding of pig LDL to the LDL receptor, and may not be necessary for the binding of human LDL to the LDL receptor.

Amino Acid Sequence↗
PubMed1988

[Clinical implication of serum antibody to Thomsen-Friedenreich antigen in patients with gynecological malignancies].

Thomsen-Friedenreich antigen (T-antigen) is a carbohydrate antigen that is expressed in a variety of cancer tissues. T-antigen is thought to have an antigenicity because circulating T antibodies can be detected as natural antibodies in humans. In this study, we examined the serum T antibody titers in patients with gynecological cancer using the hemagglutination test, and studied the relationship between the expression of T-antigen in cancer tissues and serum TA-4 levels and serum T antibody titers. Serum T antibody titers in patients with gynecological cancer were lower than those in normal controls, especially in endometrial and ovarian cancer (p less than 0.05) in which T-antigen was strongly expressed. Furthermore, the low antibody titers correlated with the expression of T-antigen in cancer tissues. T antibody titers significantly increased (p less than 0.01) after operation and the inverse relationship was found with the levels of circulating TA-4 in cervical cancer patients. These findings suggests that patients with gynecological cancer immunologically responded to T-antigen and the measurement of circulating T antibodies may be useful as an indicator of the progression of cancer in tissues.

Antibodies↗
PubMed1988

Postnatal development of the mouse temporal muscle and effects of a fine-grained diet on the muscle spindle.

The postnatal development of the mouse temporal muscle and effects of a fine-grained diet on muscle spindles were investigated. On d 25 after birth, 3 types of extrafusal muscle fibers could be distinguished on the basis of SDH activity, but not on the basis of their diameters. And in 50-d-old mice, 3 types of the muscle fibers had different diameters each other. In intrafusal muscle fibers, the postnatal changes of the SDH activity were similar to those of extrafusal muscle fibers, but the diameter distribution showed unimodal statistical distribution from 10th to 50th postnatal day. On the other hand, in control 180-d-old mice, 80 percent of muscle spindles in the temporal muscle had complete annulospiral endings, but the ratio of muscle spindles with complete annulospiral endings was decreased significantly in mice fed a fine-grained diet. The diet also decreased the diameter of the endings significantly. These results suggest that the main changes in the morphological and functional properties of the mouse temporal muscle occur in during and early after weaning period, and that normal mastication is needed to maintain the homeostatic condition of the mouse temporal muscle.

Animals↗
PubMed1988

Distribution of erythrocyte in a model vessel exposed to inhomogeneous magnetic fields.

In order to investigate magnetic field effects on blood flow, changes in the flow of erythrocytes in a model branched vessel were observed in an inhomogeneous magnetic field. The magnetic field was applied perpendicular to the straight vessel before branching. When the suspension containing paramagnetic erythrocytes with high spin methemoglobin or deoxygenated hemoglobin flowed in the model vessel, the erythrocytes were attracted towards the stronger magnetic field (i.e. to the side branch) and an excess flow of erythrocytes to the side branch was detected. This excess flow of erythrocytes to the side branch was the highest at a hematocrit of about 5% for the suspension containing erythrocytes with high spin methemoglobin. In the case of mixed suspensions containing erythrocytes with high spin methemoglobin and oxygenated erythrocytes, the excess flow of erythrocytes to the side branch reached its maximum at the "partial hematocrit" for the paramagnetic erythrocyte of around 5% and remained nearly constant with a further increase of the "partial hematocrit." The effect of magnetic field decreased as the flow velocity increased. These results are explained with the paramagnetism of erythrocytes and with the assumption of a hydrodynamic interaction among erythrocytes which are pulled in the direction of the magnetic field. It is suggested that a strong inhomogeneous magnetic field is not totally negligible to the blood circulation.

Blood Circulation↗
PubMed1987

Effect of temperature on the velocity of erythrocyte aggregation.

The velocity of the aggregation of human erythrocytes was examined in the range of 5-43 degrees C with a rheoscope combined with a video camera, an image analyzer and a computer. (1) With increasing temperature, the velocity of erythrocyte aggregation induced by fibrinogen, immunoglobulin G and artificial macromolecules (dextran of 70 kDa and poly(glutamic acid) of 50 kDa) increased. However, the relationship between the velocity of erythrocyte aggregation and the temperature was different among these macromolecules. (2) In 70% autologous plasma, the velocity of erythrocyte aggregation was minimum at 15-18 degrees C, and increased at both higher and lower temperatures. (3) The shape of erythrocyte aggregates in 12 mumol/l fibrinogen (containing 770 mumol/l albumin) and in 70% autologous plasma was dependent on temperature: three-dimensional below 15-18 degrees C and one-dimensional (mainly rouleaux) above 15-18 degrees C. However, the shape of aggregates in 27 mumol/l immunoglobulin G (containing 770 mumol/l albumin) was three-dimensional in all temperature ranges. (4) The temperature dependency of erythrocyte aggregation was discussed in terms of the changes of medium viscosity, of erythrocyte properties and of bridging macromolecules.

Adult↗