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Biomedical subjects

S Tajima

Publications and source records attributed to S Tajima.

At least 325 records · Page 18Linked to original sources
PubMed1992

Site-directed mutagenesis of an apolipoprotein E mutant, apo E5(Glu3----Lys) and its binding to low density lipoprotein receptors.

Apo E5(Glu3----Lys) is a naturally occurring apolipoprotein E (apo E) mutant found in patients with hyperlipoproteinemia and atherosclerosis. It has been shown to have a high affinity for low density lipoprotein (LDL) receptors. In this study, mutant apo E5 was produced by Chinese hamster ovary cells by means of an in vitro site-directed mutagenesis technique, and its LDL receptor binding activity was assessed. The apo E5 obtained from gene expression bound more readily to the LDL receptor than did plasma apo E3. The concentrations required for 50% competitive binding of 125I-labeled LDL to the LDL receptors were 58.9 ng/ml for plasma apo E3 and 25.7 ng/ml for the expressed apo E5. The expressed apo E5 displayed 229% normal binding. This result is highly consistent with that obtained with plasma apo E5, which showed 217% normal binding. Although the experimental apo E isoproteins contained more sialic acid than plasma apo E, the extent of sialylation had no effect on the receptor binding of apo E.

Animals↗
PubMed1992

Competitive protein binding assay for activin A/EDF using follistatin determination of activin levels in human plasma.

A sensitive and specific protein binding assay for activin A/EDF (activin) was developed using follistatin as a binding protein and [125I] labelled activin as a tracer. As 50% acetonitrile (CH3CN) separated free and follistatin-bound activin, plasma pretreated with an equal volume of CH3CN was used as the assay sample and B/F separation was also done with 50% CH3CN. The recovery of the assay was 85.0% and its sensitivity was 0.5 ng/ml. Crossreactivity with inhibin A was 1.8%. The mean plasma level of follistatin-free activin in normal subjects was 1.3 +/- 0.7%. (M +/- SD) ng/ml. Plasma free activin levels were generally elevated in patients with chronic renal failure or hematological diseases associated with anemia.

Activins↗
PubMed1992

Ascorbic acid and transforming growth factor-beta 1 increase collagen biosynthesis via different mechanisms: coordinate regulation of pro alpha 1(I) and Pro alpha 1(III) collagens.

The specific mechanisms of collagen induction in human dermal fibroblasts by ascorbic acid and transforming growth factor-beta 1 (TGF-beta 1) and their effect in combination are uncertain. Collagen synthesis and steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen RNA were examined in human dermal fibroblasts treated with 100 microM ascorbic acid, 2.5 ng/ml TGF-beta 1, or both. Within 72 h ascorbic acid and TGF-beta 1 had increased collagen synthesis by 2.55 +/- 0.32- and 1.98 +/- 0.13-fold, respectively; in the presence of both, collagen synthesis increased 4.51 +/- 0.74-fold, appearing additive. Ascorbic acid acts specifically by increasing relative collagen synthesis whereas TGF-beta 1 increases overall protein synthesis. Steady-state levels of the pro alpha 1(I) collagen (5.8 and 4.8 kb) and pro alpha 1(III) collagen (5.4 and 4.8 kb) mRNAs were examined independently. Under each condition the steady-state levels of the longer transcripts for pro alpha 1(I) and pro alpha 1(III) collagens appeared coordinately and preferentially elevated. In the presence of both ascorbic acid and TGF-beta 1 the steady-state RNA levels did not increase in an additive manner, suggesting that the additive increase in collagen synthesis results from additional post-transcriptional mechanisms.

Ascorbic Acid↗
PubMed1992

A new method for correction of Stahl's ear.

Stahl's ear is characterized by a third crus, a flat helix, hypoplasia or total absence of the superior crus, and deformity of the scaphoid fossa. There are various methods for the correction of Stahl's ear, but the surgical correction of this deformity is more difficult than it appears. We recently devised a new surgical method of our own. During the past 4 years, we treated 5 patients with Stahl's ear with this procedure. Our procedure can be used in every kind of deformity of Stahl's ear and can get satisfactory results.

Cartilage↗
PubMed1992

Biochemical study on the process of skin graft take.

Investigations on the process of skin graft take have been performed by many investigators and it has been shown that skin grafts become viable after revascularization from the graft bed after passing through a certain period of circulatory interruption. However, there are some disagreements between researchers regarding the role played by serum and the onset time of revascularization. We have investigated the changes in adenosine 5'-triphosphate (ATP) and glucose levels of skin grafts in rats to understand the biochemical process of skin graft take. A total of 250 male Wistar rats were used, and 450-microns split-thickness skin grafts were cut from their backs using a dermatome. In Group 1, the skin graft was grafted onto the dorsal fascia of the same rat. In Group 2, a 191-microns-thick Millipore filter with 1.5-microns pores was interposed between the graft and the dorsal fascia to inhibit revascularization. In Group 3, the skin graft was enveloped in a piece of gauze containing physiological saline solution and incubated at 37 degrees C. Skin grafts were removed at 6, 12, and 24 hours as well as on days 2, 3, 4, 5, 6, and 7 after grafting. The ATP and glucose levels were extracted from the grafts and quantitated using high-performance liquid chromatography. In Group 1, the ATP and glucose levels in the graft decreased rapidly after grafting; the ATP level fell to approximately 30% of that before grafting and glucose to about 20%, on days 2 and 3, respectively. Thereafter, these levels increased gradually.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

The metabolism of skin grafts stored with excess carbon dioxide.

In Japan, the long-term storage of cereals and foods in the presence of excess carbon dioxide is already a practical reality. The present study was conducted to assess the metabolic changes in skin grafts during storage in the presence and absence of excess carbon dioxide, with the aim of seeking a simple and effective method to prolong skin-graft viability during storage. In experiment 1, 120 male Wistar rats weighing 250 to 300 gm were used. A split-thickness skin graft 450 microns in thickness was harvested from the back of each rat with a dermatome and was divided into two pieces for separate storage. One piece was stored in normal air at 4 degrees C (control grafts), and the other was stored in a gas mixture composed of 20% O2, 20% CO2, and 60% N2 at 4 degrees C (CO2 grafts). Metabolic changes in the skin grafts during storage were investigated by ATP and glucose assays. In experiment 2, 60 male Wistar rats were used. Collection and storage of the split-thickness skin grafts were performed as in experiment 1. In both groups, skin grafts were stored for 1, 2, or 3 weeks, and the oxygen consumption rate of each graft was determined. Experiment 3 used 80 male Wistar rats and the same procedure as in experiment 1; split-thickness skin grafts were harvested, divided into two pieces, and stored for 1, 2, or 3 weeks. In both groups, the stored skin grafts were regrafted onto the backs of the same donor rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

Progressive facial hemiatrophy: report of five cases and biochemical analysis of connective tissue.

Five cases of progressive facial hemiatrophy (PFH) are reported. A nonindurated depression on normal-colored skin was observed in the cheeks of 3 subjects, and 2 patients showed indurated, pigmented atrophic lesions associated with linear scleroderma or generalized morphea. Lipoatrophy with mild subcutaneous fibrosis was observed histologically in the patients with nonindurated depressions. In contrast, the patients with indurated lesions exhibited a marked dermal fibrosis and the disappearance of appendices in the dermis. When compared with unaffected skin used as a control, collagen and glycosaminoglycan contents were not different in diseased areas. However, the dermatan sulfate/hyaluronic acid ratio was increased 1.5- to 3.2-fold in PFH patients regardless of their clinical and histological differences. These results suggest that both types of PFH may be based on a similar connective tissue disorder.

Adolescent↗
PubMed1992

Localization of elastic fibers and elastin mRNA in the uvea of chick embryo.

The distribution of elastic fibers and elastin mRNA was studied in the uvea of 19-day-old chick embryos by light and electron microscopy and in situ hybridization techniques using a 35S-labeled RNA probe. Light and electron microscopic examination revealed that elastic fibers were present in the uveal portion of the ciliary body, but not in the posterior choroid. Electron microscopically, elastic fibers were also found in Bruch's membrane. Abundant amounts of elastin mRNA were strictly localized in the fibroblasts in the uveal portion of the ciliary body, and no elastin mRNA was found in any of the cells in the posterior choroid by in situ hybridization. Cultured uveal tissue obtained from the ciliary body was found to produce large amounts of tropoelastin as compared with cultured posterior choroid. Using V8 protease peptide mapping and Northern blot analysis, the tropoelastin and its mRNA produced by the ciliary body were identical to those produced by the smooth muscle cells in the aorta. The results suggest that elastin is synthesized in the ciliary body, acting as a supporting substance in this area.

Animals↗
PubMed1992

Siblings with normal LDL receptor activity and severe hypercholesterolemia.

We report about a brother and sister having clinical symptoms similar to those of homozygous familial hypercholesterolemia (FH) but surprisingly who have normal low density lipoprotein (LDL) receptor activities (M. Harada-Shiba et al, J Jpn Atheroscler Soc 1991; 19:227-242). The LDL receptor activities in the cultured fibroblasts of the patients were compared with those of FH heterozygotes and homozygotes for the LDL receptor mutation. The LDL receptor activities in the cultured fibroblasts of the patients were in the normal range, but their plasma cholesterol concentrations were similar to patients with homozygous FH. After the plasma LDL was removed by plasmapheresis in both patients, plasma cholesterol levels started to increase. The "rebound" of plasma cholesterol was compared with those for heterozygous and homozygous FH. The plasma cholesterol levels of the patients, which were greater than 410 mg/dl 2 weeks after plasmapheresis, were much higher than those of FH heterozygotes (232-311 mg/dl) but similar to those of FH homozygotes (345-464 mg/dl). The urinary mevalonate excretion rate, which reflects the rate of whole-body cholesterol synthesis, was higher for the brother (patient 1, 32.6 nmol/kg.day-1) than for the normal subjects (17.7 +/- 4.1 nmol/kg.day-1) but was similar to those of FH homozygotes (31.2 +/- 4.3 nmol/kg.day-1) and heterozygotes (29.8 +/- 10.9 nmol/kg.day-1). To estimate the catabolic and production rates of cholesterol in the brother, the time course for the increment in the total cholesterol level after plasmapheresis was analyzed by the two-compartment model.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[A new operative mode for sphenoclival regions; trans Le Fort I approach].

Tumors in the sphenoclival region have conventionally been approached transseptally (transsphenoidally) or transorally; however, the following disadvantages have not allowed wide application of these approaches; 1) limited operative field, especially at the lateral side, 2) unsatisfactory repair for the dural defects. We have applied Le Fort I osteotomy for lesions in this region, and we called the operative technique, by which we approached via the space that was obtained by moving the osteomized maxillary bone to the mandibular bone, trans Le Fort I approach. We have applied this approach in 5 patients and obtained a substantially wider operative field than that obtained by the conventional approach, with successful results. Three out of 5 patients were operated on via this trans Le Fort I approach, and the other 2 via this approach combined with mandibular midsplitting, which was performed to make a median osteotomy of the mandibular bone to accommodate osteomized maxillary bone (this technique is referred to as trans Le Fort I with mandibular midsplitting). The tumor was totally resected in 4 cases, and subtotally in 1 case with wide dural incision. One case was temporarily complicated with diabetes insipidus after the operation, but there were no complications in the remaining cases. Prognoses in patients were good in 2, fair in 1, and poor in 2 due to tumor progression. Although tracheostomy is inevitable with this approach, we think this technique is beneficial in operations of the skull base because, compared with conventional techniques, a somewhat wider operative field can be expected with this technique.

Adult↗