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Biomedical subjects

S Tajima

Publications and source records attributed to S Tajima.

At least 433 records · Page 24Linked to original sources
PubMed1981

Homozygous familial hypercholesterolemia mutant with a defect in internalization of low density lipoprotein.

During studies on binding of low density lipoprotein (LDL) to fibroblasts from patients with the homozygous form of familial hypercholesterolemia (FH), a unique line was derived from subject M.N. This line could bind as much LDL as normal cells, or even more. However, like fibroblasts from other patients with the homozygous form of FH, it failed to show regulation of cholesterol synthesis. Analyses of the LDL receptors showed that this line could not mediate internalization of receptor-bound LDL. Studies on the fibroblasts of the parents of this subject showed that the inability to internalize LDL was hereditary and that the subject was a pure homozygote for this defect. The plausibility of this finding was supported by the fact that her parents were first cousins. The possible existence of a homozygous state of this defect was predicted by Goldstein et al. [Goldstein, J. L., Brown, M. S. & Stone, N. J. (1977) Cell 12, 629-41], but an actual case of the internalization defect in a pure homozygous form had not been found. There were no differences from normal cells in the nature of the LDL binding activity of this line, such as in its specificity, affinity, or Ca2+ requirement.

Adult↗
PubMed1981

Collagen synthesis by human skin fibroblasts in culture: studies of fibroblasts explanted from papillary and reticular dermis.

Matched human skin fibroblast cultures were established from papillary and reticular dermis. Papillary dermal fibroblasts exhibited increased plating efficiency, exponential growth, and confluent density when compared with their matched reticular dermal cultures. Collagen synthesis by these cells, however, was essentially similar regardless of their origin. Relative collagen synthesis was similar at confluent densities. No differences in type specific collagen synthesis could be detected; relative amounts of types I and III collagens in culture media and types I, III, and AB collagens in the cellular pellet were similar. Type I pC collagen was consistently elevated in culture media from reticular dermal fibroblasts when compared to papillary dermal fibroblasts. The significance of this difference in procollagen processing is unknown.

Adult↗
PubMed1981

[Electromyographic feedback for cerebral children (adults): on the residual tension of muscle (author's transl)].

In order to investigate the residual tension of muscle in cerebral palsied (CP) children (adults) and the effect of EMG feedback on its relaxation processes, 5 normal children and 15 CP children, including one adult, were asked to flex their elbows gradually, then increase the tension with full flexion, and finally relax as quickly as possible under three conditions: pre-feedback, feedback, and post-feedback. Under the feedback condition, a meter display was provided. Results were as follows: (1) All except one in the CP group showed more residual tension than the normals at the pre-feedback condition. (2) Under the feedback condition, the time to relax was shortened significantly in the CP group. (3) The CPs could be classified into following four types by the influence of EMG feedback. (a) Type A (N = 2) showed no change. (b) Type B (N = 9) improved. (c) Type C (N = 1) improved in the latter half of the feedback condition, though it increased tension in the first half. (d) Type D (N = 2) increased conversely under the feedback condition.

Adolescent↗
PubMed1980

Temporal double inversion method in reshaping the temporal bulging in a case of Apert's syndrome.

A case is reported of Apert's syndrome with severe bilateral balloonings of the temporal region in addition to other typical craniofacial deformities. He had had three previous strip craniectomies. His mentality and intelligence were normal. In order to improve his deformities, the following steps were carried out: 1. 1.5 cm frontal advancement with reshaping the horizontal arc of the supraorbital ridge by out-fracturing. 2. Bilateral temporal double turnover method with internal decompression of the temporal lobe by resection of the sphenoid wing abnormally roofing the temporal lobe. 3. Reduction of the height of the cranial vault. The result was gratifying.

Acrocephalosyndactylia↗
PubMed1980

Topological studies of the membrane-binding segment of cytochrome b5 embedded in phosphatidylcholine vesicles.

Carboxypeptidase Y (CPY) digestion of cytochrome b5 incorporated into single-walled liposomes of egg phosphatidylcholine (PC) resulted in the release of 25 amino acid residues form each molecule of the cytochrome and concomitant detachment of the cytochrome from the vesicles. This finding suggests that the COOH-terminus of the incorporated cytochrome is exposed to the outer surface of the liposomal membrane, since the cytochrome-carrying vesicles were shown to be impermeable to macromolecules such as dextran T-40 by isopycnic centrifugation studies. The possibility that CPY had attacked a small amount of free cytochrome b5 which was in equilibrium with the liposome-bound cytochrome could be excluded by the finding that transfer of the bound cytochrome to the unbound state was a much slower process than CPY-induced detachment of cytochrome b5. CPY could also attack the COOH-terminus of cytochrome b5 embedded in dipalmitoyl-PC liposomes even below the phase transition temperature of the synthetic phospholipid. Moreover, the tyrosine residue(s) near the COOH-terminus of the PC vesicle-bound cytochrome could be readily iodinated by the action of lactoperoxidase added externally. These observations indicate that the COOH-terminus of the liposome-bound cytochrome, like its heme-containing, hydrophilic domain, is exposed to the outer surface of the vesicular membrane. The cytochrome detached from the vesicles by CPY digestion could neither rebind to the liposomes nor form an oligomeric aggregate, suggesting that CPY had removed all the amino acid residues which are required for the protein to bind to membranes. The mechanism of CPY-induced detachment of cytochrome b5 from liposomes and the size of the peptide segment which is directly involved in the interaction of the cytochrome with the lipid bilayer membranes are discussed.

Amino Acid Sequence↗
PubMed1980

Nasal septum osteotome.

A new chisel for nasal septum osteotomy in craniofacial surgery is reported. With the aid of a guide wire, the cranial base is completely protected from inadvertent penetration. The direction of osteotomy can be changed because of the chisel's central fenestration, even if placed incorrectly at the beginning.

Animals↗
PubMed1980

Allergenicity of major component proteins of soybean.

Allergenic activities of major component proteins of soybean 11S-, 7S- and 2S-globulins were examined by the radioallergosorbent test (RAST) and by RAST inhibition experiments with the sera from soybean-sensitive patients. The reactivity with specific IgE antibody was found in all fractions. There was considerable cross-reactivity among three fractions, and 2S-globulin had the highest allergen potency to inhibit the RAST against 11S, 7S- and 2S-globulin. When the fractions were heat-treated at 80, 100 and 120 degrees C for 30 min, the RAST reactivity of 2S-globulin heated at 80 degrees C for 30 min was slightly enhanced, while that of others was reduced to 39--75% of that of the native globulin. IgE antibody could be produced in BALB/c mice only with one of the three fractions, i. e. 2S-globulin, and the produced IgE antibody lacked reactivity with 11S- and 7S-globulin.

Allergens↗
PubMed1980

Isolation and partial characterization of collagen fibrils, fibers and fiber-bundles from insoluble calf dermis.

Collagen fibrils, fibers and fiber bundles have been isolated from insoluble calf skin chips by disaggregation with a neutral salt buffer followed by differential centrifugation. The ratio of type I collagen/type III collagen was relatively constant, regardless of the size of the fibrous materials. On the other hand, the ratios of glycosaminoglycans/collagen and non-collagenous glycoproteins/collagen were significantly higher in the thinner fiber fractions. However, the ratio of hyaluronic acid to dermatan sulfate was unchanged. The role of the non-collanenous constituents in collagen fibrillogenesis in vivo is discussed.

Amino Acids↗
PubMed1980

Distribution of macromolecular components in calf dermal connective tissue.

Distribution of type I and type III collagens, glycosaminoglycans and non-collagenous glycoprotein(s) in calf skin has been investigated in five horizontally sliced layers of 250 microns thickness from the surface to the bottom. The upper dermis (the top three layers) consisting of fine collagen fibers had a higher ratio of hyaluronic acid/dermatan sulfate than the lower layers where coarse collagen fibers are mainly located. The ratios of total glycosaminoglycans/collagen and glycoprotein(s) collagen were higher in the upper dermis, while dermatan sulfate/collagen remained constant throughout the dermis. Relative content of type III collagen/total collagen (type I + III collagens) was also higher in the upper dermis. Possible involvement of these macromolecular constituents in collagen fibrillogenesis in vivo is also discussed.

Amino Acids↗
PubMed1980

The treatment of fractures involving the frontobasal region.

The treatment of frontobasal fractures has been reported with special reference to involvement of the upper paranasal sinuses. The importance of primary reconstruction of nasal, orbital, and cranial cavities by bone grafts after thorough debridement is stressed.

Adolescent↗
PubMed1979

Inhibition of the binding of cytochrome b5 to phosphatidylcholine vesicles by cholesterol.

The binding of cytochrome b5 to single-walled liposomes of egg phosphatidylcholine was inhibited by the presence of cholesterol in the lipid bilayer under conditions where a limited amount of liposomes was incubated with the cytochrome. Since similar conditions seem to apply for the binding of cytochrome b5 to erythrocyte ghosts, this observation supports the conclusion of Enomoto and Sato (Enomoto, K. and Sato, R. (1977) Biochim. Biophys. Acta 466, 136--147) that the localization of cholesterol on the outer surface of the ghost membrane prevents the binding of cytochrome b5 to this surface. The finding reported by Roseman et al. (Roseann, M.A., Holloway, P.W. and Calabro, M.A. (1978) Biochmi. Biophys. Acta 507, 552--556) that cholesterol did not prevent the cytochrome binding to phosphatidylcholine liposomes in the presence of a large excess of liposomes could be confirmed in the present study, but this does not contradict the abovementioned conclusion.

Cholesterol↗
PubMed1979

Primary structure of the membrane-binding segment of rabbit cytochrome b5.

The primary structure of the membrane-binding segment of rabbit cytochrome b5 has been determined. This segment, prepared by trypsin digestion of the intact protein, consists of 43 amino acid residues and corresponds to the COOH-terminal end (residues 91-133) of the parent molecule. Deduction of the primary structure was based on automated sequence analysis of the whole segment as well as manual and dansyl-Edman degradations of peptide fragments produced by CNBr cleavage and partial acid hydrolysis. The sequence obtained is: Leu-Ser-Lys-Pro-Met-Glu-Thr-Leu-Ile-Thr-Thr-Val-Asn-Ser-Asn-Ser-Ser-Trp-Trp-Thr-Asn-Trp-Val-Ile-Pro-Ala-Ile-Ser-Ala-Leu-Ile-Val-Ala-Leu-Met-Tyr-Arg-Leu-Tyr-Met-Ala-Asp-Asp. This sequence is 63 to 81% homologous with respect to those determined for the membrane-binding segments of equine, porcine and bovine cytochrome b5. The interaction of this segment with phospholipid bilayer membranes is discussed, and a prediction of its secondary structure is also presented.

Amino Acid Sequence↗
PubMed1978

Nature of tryptic attack on cytochrome b5 and further evidence for the two-domain structure of the cytochrome molecule.

Rabbit cytochrome b5 was incorporated into single-walled phosphatidylcholine liposomes, and the cytochrome b5-liposome complex thus formed was digested with trypsin. Protein chemical characterization indicated that the main products formed were 1) a hydrophilic (heme-containing) fragment of the cytochrome corresponding to the sequence consisting of the masked NH2-terminus through residue 88, 2) a hydrophobic peptide which spans residue 91 to the COOH-terminus (residue 133), and 3) a dipeptide, seryl-lysine, derived from residues 89 and 90. The hydrophobic peptide was obtained in the form of its complex with liposomes. It was concluded that trypsin cleaved rather specifically the peptide bonds between residues 88 and 89 (Arg-Ser) and between residues 90 and 91 (Lys-Leu). Tryptic digestion of free, unbound cytochrome b5 also resulted in the cleavage of the same peptide bonds. These results are not consistent with the proposal of Visser et al. (Visser, L., Robinson, N.C., & Tanford, C. (1975) Biochemistry 14, 1194-1199) that the hydrophilic and hydrophobic domains of cytochrome b5 are connected to each other by a link peptide consisting of some 15 amino acid residues and that this link peptide can be cut out by the action of trypsin. The circular dichroism spectrum of intact cytochrome b5 or its complex with liposomes in the far-ultraviolet region was closely similar to the sum of the spectra of the hydrophilic fragment and the hydrophobic peptide (or its complex with liposomes). This indicates that the tryptic cleavage of the cytochrome molecule does not induce any significant changes in the conformations of the hydrophilic and hydrophobic moieties of the molecule and thus provides further evidence that the three-dimensional structures of the two domains are independent of each other.

Amino Acids↗